Effects of sea-level rise on salt water intrusion near a coastal well field in southeastern Florida

USGS Publications Warehouse

Langevin, Christian D.; Zygnerski, Michael

2013-01-01

A variable-density groundwater flow and dispersive solute transport model was developed for the shallow coastal aquifer system near a municipal supply well field in southeastern Florida. The model was calibrated for a 105-year period (1900 to 2005). An analysis with the model suggests that well-field withdrawals were the dominant cause of salt water intrusion near the well field, and that historical sea-level rise, which is similar to lower-bound projections of future sea-level rise, exacerbated the extent of salt water intrusion. Average 2005 hydrologic conditions were used for 100-year sensitivity simulations aimed at quantifying the effect of projected rises in sea level on fresh coastal groundwater resources near the well field. Use of average 2005 hydrologic conditions and a constant sea level result in total dissolved solids (TDS) concentration of the well field exceeding drinking water standards after 70 years. When sea-level rise is included in the simulations, drinking water standards are exceeded 10 to 21 years earlier, depending on the specified rate of sea-level rise.

Sea-level rise caused by climate change and its implications for society

PubMed Central

MIMURA, Nobuo

2013-01-01

Sea-level rise is a major effect of climate change. It has drawn international attention, because higher sea levels in the future would cause serious impacts in various parts of the world. There are questions associated with sea-level rise which science needs to answer. To what extent did climate change contribute to sea-level rise in the past? How much will global mean sea level increase in the future? How serious are the impacts of the anticipated sea-level rise likely to be, and can human society respond to them? This paper aims to answer these questions through a comprehensive review of the relevant literature. First, the present status of observed sea-level rise, analyses of its causes, and future projections are summarized. Then the impacts are examined along with other consequences of climate change, from both global and Japanese perspectives. Finally, responses to adverse impacts will be discussed in order to clarify the implications of the sea-level rise issue for human society. PMID:23883609

Determining the response of sea level to atmospheric pressure forcing using TOPEX/POSEIDON data

NASA Technical Reports Server (NTRS)

Fu, Lee-Lueng; Pihos, Greg

1994-01-01

The static response of sea level to the forcing of atmospheric pressure, the so-called inverted barometer (IB) effect, is investigated using TOPEX/POSEIDON data. This response, characterized by the rise and fall of sea level to compensate for the change of atmospheric pressure at a rate of -1 cm/mbar, is not associated with any ocean currents and hence is normally treated as an error to be removed from sea level observation. Linear regression and spectral transfer function analyses are applied to sea level and pressure to examine the validity of the IB effect. In regions outside the tropics, the regression coefficient is found to be consistently close to the theoretical value except for the regions of western boundary currents, where the mesoscale variability interferes with the IB effect. The spectral transfer function shows near IB response at periods of 30 degrees is -0.84 +/- 0.29 cm/mbar (1 standard deviation). The deviation from = 1 cm /mbar is shown to be caused primarily by the effect of wind forcing on sea level, based on multivariate linear regression model involving both pressure and wind forcing. The regression coefficient for pressure resulting from the multivariate analysis is -0.96 +/- 0.32 cm/mbar. In the tropics the multivariate analysis fails because sea level in the tropics is primarily responding to remote wind forcing. However, after removing from the data the wind-forced sea level estimated by a dynamic model of the tropical Pacific, the pressure regression coefficient improves from -1.22 +/- 0.69 cm/mbar to -0.99 +/- 0.46 cm/mbar, clearly revealing an IB response. The result of the study suggests that with a proper removal of the effect of wind forcing the IB effect is valid in most of the open ocean at periods longer than 20 days and spatial scales larger than 500 km.

Cardiovascular autonomic modulation and activity of carotid baroreceptors at altitude.

PubMed

Bernardi, L; Passino, C; Spadacini, G; Calciati, A; Robergs, R; Greene, R; Martignoni, E; Anand, I; Appenzeller, O

1998-11-01

1. To assess the effects of acute exposure to high altitude on baroreceptor function in man we evaluated the effects of baroreceptor activation on R-R interval and blood pressure control at high altitude. We measured the low-frequency (LF) and high-frequency (HF) components in R-R, non-invasive blood pressure and skin blood flow, and the effect of baroreceptor modulation by 0. 1-Hz sinusoidal neck suction. Ten healthy sea-level natives and three high-altitude native, long-term sea-level residents were evaluated at sea level, upon arrival at 4970 m and 1 week later.2. Compared with sea level, acute high altitude decreased R-R and increased blood pressure in all subjects [sea-level natives: R-R from 1002+/-45 to 775+/-57 ms, systolic blood pressure from 130+/-3 to 150+/-8 mmHg; high-altitude natives: R-R from 809+/-116 to 749+/-47 ms, systolic blood pressure from 110+/-12 to 125+/-11 mmHg (P<0.05 for all)]. One week later systolic blood pressure was similar to values at sea level in all subjects, whereas R-R remained elevated in sea-level natives. The low-frequency power in R-R and systolic blood pressure increased in sea-level natives [R-R-LF from 47+/-8 to 65+/-10% (P<0.05), systolic blood pressure-LF from 1.7+/-0. 3 to 2.6+/-0.4 ln-mmHg2 (P<0.05)], but not in high-altitude natives (R-R-LF from 32+/-13 to 38+/-19%, systolic blood pressure-LF from 1. 9+/-0.5 to 1.7+/-0.8 ln-mmHg2). The R-R-HF decreased in sea-level natives but not in high-altitude natives, and no changes occurred in systolic blood pressure-HF. These changes remained evident 1 week later. Skin blood flow variability and its spectral components decreased markedly at high altitude in sea-level natives but showed no changes in high-altitude natives. Neck suction significantly increased the R-R- and systolic blood pressure-LF in all subjects at both sea level and high altitude.3. High altitude induces sympathetic activation in sea-level natives which is partially counteracted by active baroreflex. Despite long-term acclimatization at sea level, high-altitude natives also maintain active baroreflex at high altitude but with lower sympathetic activation, indicating a persisting high-altitude adaptation which may be genetic or due to baroreflex activity not completely lost by at least 1 year's sea-level residence.

How effective is albedo modification (solar radiation management geoengineering) in preventing sea-level rise from the Greenland Ice Sheet?

NASA Astrophysics Data System (ADS)

Applegate, Patrick J.; Keller, Klaus

2015-08-01

Albedo modification (AM) is sometimes characterized as a potential means of avoiding climate threshold responses, including large-scale ice sheet mass loss. Previous work has investigated the effects of AM on total sea-level rise over the present century, as well as AM’s ability to reduce long-term (≫103 yr) contributions to sea-level rise from the Greenland Ice Sheet (GIS). These studies have broken new ground, but neglect important feedbacks in the GIS system, or are silent on AM’s effectiveness over the short time scales that may be most relevant for decision-making (<103 yr). Here, we assess AM’s ability to reduce GIS sea-level contributions over decades to centuries, using a simplified ice sheet model. We drive this model using a business-as-usual base temperature forcing scenario, as well as scenarios that reflect AM-induced temperature stabilization or temperature drawdown. Our model results suggest that (i) AM produces substantial near-term reductions in the rate of GIS-driven sea-level rise. However, (ii) sea-level rise contributions from the GIS continue after AM begins. These continued sea level rise contributions persist for decades to centuries after temperature stabilization and temperature drawdown begin, unless AM begins in the next few decades. Moreover, (iii) any regrowth of the GIS is delayed by decades or centuries after temperature drawdown begins, and is slow compared to pre-AM rates of mass loss. Combined with recent work that suggests AM would not prevent mass loss from the West Antarctic Ice Sheet, our results provide a nuanced picture of AM’s possible effects on future sea-level rise.

Contribution of vertical land motions to coastal sea level variations: a global synthesis of multisatellite altimetry, tide gauge and GPS measurements

NASA Astrophysics Data System (ADS)

Pfeffer, Julia; Allemand, Pascal

2016-04-01

Coastal sea level variations result from a complex mix of climatic, oceanic and geodynamical processes driven by natural and anthropogenic constraints. Combining data from multiple sources is one solution to identify particular processes and progress towards a better understanding of the sea level variations and the assessment of their impacts at coast. Here, we present a global database merging multisatellite altimetry with tide gauges and Global Positioning System (GPS) measurements. Vertical land motions and sea level variations are estimated simultaneously for a network of 886 ground stations with median errors lower than 1 mm/yr. The contribution of vertical land motions to relative sea level variations is explored to better understand the natural hazards associated with sea level rise in coastal areas. Worldwide, vertical land motions dominate 30 % of observed coastal trends. The role of the crust is highly heterogeneous: it can amplify, restrict or counter the effects of climate-induced sea level change. A set of 182 potential vulnerable localities are identified by large coastal subsidence which increases by several times the effects of sea level rise. Though regional behaviours exist, principally caused by GIA (Glacial Isostatic Adjustment), the local variability in vertical land motion prevails. An accurate determination of the vertical motions observed at the coast is fundamental to understand the local processes which contribute to sea level rise, to appraise its impacts on coastal populations and make future predictions.

Sea-level rise caused by climate change and its implications for society.

PubMed

Mimura, Nobuo

2013-01-01

Sea-level rise is a major effect of climate change. It has drawn international attention, because higher sea levels in the future would cause serious impacts in various parts of the world. There are questions associated with sea-level rise which science needs to answer. To what extent did climate change contribute to sea-level rise in the past? How much will global mean sea level increase in the future? How serious are the impacts of the anticipated sea-level rise likely to be, and can human society respond to them? This paper aims to answer these questions through a comprehensive review of the relevant literature. First, the present status of observed sea-level rise, analyses of its causes, and future projections are summarized. Then the impacts are examined along with other consequences of climate change, from both global and Japanese perspectives. Finally, responses to adverse impacts will be discussed in order to clarify the implications of the sea-level rise issue for human society.(Communicated by Kiyoshi HORIKAWA, M.J.A.).

Effect of sea-level rise on salt water intrusion near a coastal well field in southeastern Florida.

PubMed

Langevin, Christian D; Zygnerski, Michael

2013-01-01

A variable-density groundwater flow and dispersive solute transport model was developed for the shallow coastal aquifer system near a municipal supply well field in southeastern Florida. The model was calibrated for a 105-year period (1900 to 2005). An analysis with the model suggests that well-field withdrawals were the dominant cause of salt water intrusion near the well field, and that historical sea-level rise, which is similar to lower-bound projections of future sea-level rise, exacerbated the extent of salt water intrusion. Average 2005 hydrologic conditions were used for 100-year sensitivity simulations aimed at quantifying the effect of projected rises in sea level on fresh coastal groundwater resources near the well field. Use of average 2005 hydrologic conditions and a constant sea level result in total dissolved solids (TDS) concentration of the well field exceeding drinking water standards after 70 years. When sea-level rise is included in the simulations, drinking water standards are exceeded 10 to 21 years earlier, depending on the specified rate of sea-level rise. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.

Coastal vulnerability assessment of Olympic National Park to sea-level rise

USGS Publications Warehouse

Pendleton, Elizabeth A.; Hammar-Klose, Erika S.; Thieler, E. Robert; Williams, S. Jeffress

2004-01-01

A coastal vulnerability index (CVI) was used to map the relative vulnerability of the coast to future sea-level rise within Olympic National Park (OLYM), Washington. The CVI scores the following in terms of their physical contribution to sea-level rise-related coastal change: geomorphology, regional coastal slope, rate of relative sea-level rise, shoreline change rates, mean tidal range and mean wave height. The rankings for each variable were combined and an index value calculated for 1-minute grid cells covering the park. The CVI highlights those regions where the physical effects of sea-level rise might be the greatest. This approach combines the coastal system's susceptibility to change with its natural ability to adapt to changing environmental conditions, yielding a quantitative, although relative, measure of the park's natural vulnerability to the effects of sea-level rise. The CVI provides an objective technique for evaluation and long-term planning by scientists and park managers. The Olympic National Park coast consists of rocky headlands, pocket beaches, glacial-fluvial features, and sand and gravel beaches. The Olympic coastline that is most vulnerable to sea-level rise are beaches in gently sloping areas.

Consequences of sea level variability and sea level rise for Cuban territory

NASA Astrophysics Data System (ADS)

Hernández, M.; Martínez, C. A.; Marzo, O.

2015-03-01

The objective of the present paper was to determine a first approximation of coastal zone flooding by 2100, taking into account the more persistent processes of sea level variability and non-accelerated linear sea level rise estimation to assess the main impacts. The annual linear rate of mean sea level rise in the Cuban archipelago, obtained from the longest tide gauge records, has fluctuated between 0.005 cm/year at Casilda and 0.214 cm/year at Siboney. The main sea level rise effects for the Cuban coastal zone due to climate change and global warming are shown. Monthly and annual mean sea level anomalies, some of which are similar to or higher than the mean sea level rise estimated for halfway through the present century, reinforce the inland seawater penetration due to the semi-daily high tide. The combination of these different events will result in the loss of goods and services, and require expensive investments for adaption.

Population dynamics of Hawaiian seabird colonies vulnerable to sea-level rise.

PubMed

Hatfield, Jeff S; Reynolds, Michelle H; Seavy, Nathaniel E; Krause, Crystal M

2012-08-01

Globally, seabirds are vulnerable to anthropogenic threats both at sea and on land. Seabirds typically nest colonially and show strong fidelity to natal colonies, and such colonies on low-lying islands may be threatened by sea-level rise. We used French Frigate Shoals, the largest atoll in the Hawaiian Archipelago, as a case study to explore the population dynamics of seabird colonies and the potential effects sea-level rise may have on these rookeries. We compiled historic observations, a 30-year time series of seabird population abundance, lidar-derived elevations, and aerial imagery of all the islands of French Frigate Shoals. To estimate the population dynamics of 8 species of breeding seabirds on Tern Island from 1980 to 2009, we used a Gompertz model with a Bayesian approach to infer population growth rates, density dependence, process variation, and observation error. All species increased in abundance, in a pattern that provided evidence of density dependence. Great Frigatebirds (Fregata minor), Masked Boobies (Sula dactylatra), Red-tailed Tropicbirds (Phaethon rubricauda), Spectacled Terns (Onychoprion lunatus), and White Terns (Gygis alba) are likely at carrying capacity. Density dependence may exacerbate the effects of sea-level rise on seabirds because populations near carrying capacity on an island will be more negatively affected than populations with room for growth. We projected 12% of French Frigate Shoals will be inundated if sea level rises 1 m and 28% if sea level rises 2 m. Spectacled Terns and shrub-nesting species are especially vulnerable to sea-level rise, but seawalls and habitat restoration may mitigate the effects of sea-level rise. Losses of seabird nesting habitat may be substantial in the Hawaiian Islands by 2100 if sea levels rise 2 m. Restoration of higher-elevation seabird colonies represent a more enduring conservation solution for Pacific seabirds. Conservation Biology ©2012 Society for Conservation Biology. No claim to original US government works.

Rising tides, rising gates: The complex ecogeomorphic response of coastal wetlands to sea-level rise and human interventions

NASA Astrophysics Data System (ADS)

Sandi, Steven G.; Rodríguez, José F.; Saintilan, Neil; Riccardi, Gerardo; Saco, Patricia M.

2018-04-01

Coastal wetlands are vulnerable to submergence due to sea-level rise, as shown by predictions of up to 80% of global wetland loss by the end of the century. Coastal wetlands with mixed mangrove-saltmarsh vegetation are particularly vulnerable because sea-level rise can promote mangrove encroachment on saltmarsh, reducing overall wetland biodiversity. Here we use an ecogeomorphic framework that incorporates hydrodynamic effects, mangrove-saltmarsh dynamics, and soil accretion processes to assess the effects of control structures on wetland evolution. Migration and accretion patterns of mangrove and saltmarsh are heavily dependent on topography and control structures. We find that current management practices that incorporate a fixed gate for the control of mangrove encroachment are useful initially, but soon become ineffective due to sea-level rise. Raising the gate, to counteract the effects of sea level rise and promote suitable hydrodynamic conditions, excludes mangrove and maintains saltmarsh over the entire simulation period of 100 years

Estimates of twenty-first century sea-level changes for Norway

NASA Astrophysics Data System (ADS)

Simpson, Matthew J. R.; Breili, Kristian; Kierulf, Halfdan P.

2014-03-01

In this work we establish a framework for estimating future regional sea-level changes for Norway. Following recently published works, we consider how different physical processes drive non-uniform sea-level changes by accounting for spatial variations in (1) ocean density and circulation (2) ice and ocean mass changes and associated gravitational effects on sea level and (3) vertical land motion arising from past surface loading change and associated gravitational effects on sea level. An important component of past and present sea-level change in Norway is glacial isostatic adjustment. Central to our study, therefore, is a reassessment of vertical land motion using a far larger set of new observations from a permanent GNSS network. Our twenty-first century sea-level estimates are split into two parts. Firstly, we show regional projections largely based on findings from the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR4) and dependent on the emission scenarios A2, A1B and B1. These indicate that twenty-first century relative sea-level changes in Norway will vary between -0.2 to 0.3 m (1-sigma ± 0.13 m). Secondly, we explore a high-end scenario, in which a global atmospheric temperature rise of up to 6 °C and emerging collapse for some areas of the Antarctic ice sheets are assumed. Using this approach twenty-first century relative sea-level changes in Norway are found to vary between 0.25 and 0.85 m (min/max ± 0.45 m). We attach no likelihood to any of our projections owing to the lack of understanding of some of the processes that cause sea-level change.

Estimation of Sea Level variations with GPS/GLONASS-Reflectometry Technique: Case Study at Stationary Oceanographic Platform in the Black Sea

NASA Astrophysics Data System (ADS)

Kurbatov, G. A.; Padokhin, A. M.

2017-12-01

In the present work we study GNSS - reflectometry methods for estimation of sea level variations using a single GNSS-receiver, which are based on the multipath propagation effects (interference pattern in SNR of GNSS signals at small elevation angles) caused by the reflection of navigational signals from the sea surface. The measurements were carried out in the coastal zone of Black Sea at the Stationary Oceanographic Platform during one-week campaign in the summer 2017. GPS/GLONASS signals at two working frequencies of both systems were used to study sea level variations which almost doubled the amount of observations compared to GPS-only tide gauge. Moreover all the measurements were conducted with 4-antenna GNSS receiver providing the opportunity for different orientations of antennas including zenith and nadir looking ones as well as two horizontally oriented ones at different azimuths. As the reference we used data from co-located wire wave gauge which showed good correspondence of both datasets. Though tidal effects are not so pronounced for the Black Sea, the described experimental setup allowed to study the effects of sea surface roughness, driven by meteorological conditions (e.g. wind waves), as well as antenna directivity pattern effects on the observed interference patterns of GPS/GLONASS L1/L2 signals (relation of the main spectral peak to the noise power) and the quality of sea level estimations.

The contribution of sea-level rise to flooding in large river catchments

NASA Astrophysics Data System (ADS)

Thiele-Eich, I.; Hopson, T. M.; Gilleland, E.; Lamarque, J.; Hu, A.; Simmer, C.

2012-12-01

Climate change is expected to both impact sea level rise as well as flooding. Our study focuses on the combined effect of climate change on upper catchment precipitation as well as on sea-level rise at the river mouths and the impact this will have on river flooding both at the coast and further upstream. We concentrate on the eight catchments of the Amazonas, Congo, Orinoco, Ganges/Brahmaputra/Meghna, Mississippi, St. Lawrence, Danube and Niger rivers. To assess the impact of climate change, upper catchment precipitation as well as monthly mean thermosteric sea-level rise at the river mouth outflow are taken from the four CCSM4 1° 20th Century ensemble members as well as from six CCSM4 1° ensemble members for the RCP scenarios RCP8.5, 6.0, 4.5 and 2.6. Continuous daily time series for average catchment precipitation and discharge are available for each of the catchments. To arrive at a future discharge time series, we used these observations to develop a simple statistical hydrological model which can be applied to the modelled future upper catchment precipitation values. The analysis of this surrogate discharge time series alone already yields significant changes in flood return levels as well as flood duration. Using the geometry of the river channel, the backwater effect of sea-level rise is incorporated in our analysis of both flood frequencies and magnitudes by calculating the effective additional discharge due to the increase in water level at the river mouth outflow, as well as its tapering impact upstream. By combining these effects, our results focus on the merged impact of changes in extreme precipitation with increases in river height due to sea-level rise at the river mouths. Judging from our preliminary results, the increase in effective discharge due to sea-level rise cannot be neglected when discussing late 21st century flooding in the respective river basins. In particular, we find that especially in countries with low elevation gradient, flood characteristics are impacted by changes in sea-level rise as far inland as 150 kilometers. Therefore, a larger population than the coastal inhabitants alone are exposed to risks of further projected increases of sea-level rise. A prime example for a megacity greatly put at risk by this is Dhaka City in Bangladesh, with a population of roughly 14 million people.

Studying the impact of climate change on flooding in 12 river basins using CCSM4 output

NASA Astrophysics Data System (ADS)

Thiele-Eich, I.; Hopson, T. M.; Gilleland, E.; Lamarque, J.; Hu, A.

2011-12-01

The goal of this study is to analyze the impact of climate change on flood frequency changes in twelve large river basins by assessing the changes in upper catchment precipitation as well as the impact of sea-level rise at the river mouths. Using the recently released model output of the CCSM4 for upper catchment precipitation in twelve large river basins as well as the sea-level rise anomalies at the respective river mouths, we assess the impact of climate change on the return periods of flooding in the individual basins. Upper catchment precipitation, discharge as well as annual mean thermosteric sea-level rise are taken from the four CCSM4 1° 20th Century ensemble members as well as from six CCSM4 1° ensemble members for the RCP scenarios RCP8.5, 6.0, 4.5 and 2.6. In a next step, return levels are compared from both 20th century and future model simulations for time slices at 2030, 2050, 2070 and 2090. It can be seen that what is e.g. a 20 year flood in present-day climate has a return period of ~15/10 years (RCP 2.6/8.5) in 2070. This effect strengthens as time progresses in the 21st century. Especially in low-lying countries such as Bangladesh, changes in sea-level rise can be expected to influence present-day flood characteristics. Sea-level rise anomalies for the 21st century are taken from CCSM4 model output at each of the river mouths. The backwater effect of sea-level rise can be estimated by referring to the geometry of the river channel and calculating an effective additional discharge both at the river mouth and inland. Judging from our work, the increase in effective discharge due to sea-level rise cannot be neglected when discussing flooding in the respective river basins. Impact of sea-level rise on changes in return levels will be investigated further. To blend both precipitation and sea-level effects together, we use extreme-value theory to calculate how the tails of the current river discharge distribution in both the lower and middle reaches of the river basins will be impacted by changing climate.

Acceleration of Sea Level Rise Over Malaysian Seas from Satellite Altimeter

NASA Astrophysics Data System (ADS)

Hamid, A. I. A.; Din, A. H. M.; Khalid, N. F.; Omar, K. M.

2016-09-01

Sea level rise becomes our concern nowadays as a result of variously contribution of climate change that cause by the anthropogenic effects. Global sea levels have been rising through the past century and are projected to rise at an accelerated rate throughout the 21st century. Due to this change, sea level is now constantly rising and eventually will threaten many low-lying and unprotected coastal areas in many ways. This paper is proposing a significant effort to quantify the sea level trend over Malaysian seas based on the combination of multi-mission satellite altimeters over a period of 23 years. Eight altimeter missions are used to derive the absolute sea level from Radar Altimeter Database System (RADS). Data verification is then carried out to verify the satellite derived sea level rise data with tidal data. Eight selected tide gauge stations from Peninsular Malaysia, Sabah and Sarawak are chosen for this data verification. The pattern and correlation of both measurements of sea level anomalies (SLA) are evaluated over the same period in each area in order to produce comparable results. Afterwards, the time series of the sea level trend is quantified using robust fit regression analysis. The findings clearly show that the absolute sea level trend is rising and varying over the Malaysian seas with the rate of sea level varies and gradually increase from east to west of Malaysia. Highly confident and correlation level of the 23 years measurement data with an astonishing root mean square difference permits the absolute sea level trend of the Malaysian seas has raised at the rate 3.14 ± 0.12 mm yr-1 to 4.81 ± 0.15 mm yr-1 for the chosen sub-areas, with an overall mean of 4.09 ± 0.12 mm yr-1. This study hopefully offers a beneficial sea level information to be applied in a wide range of related environmental and climatology issue such as flood and global warming.

Modeling Tidal Wetland Resiliency in the Face of Predicted Accelerated Sea-Level Rise

NASA Astrophysics Data System (ADS)

Schile, L. M.; Callaway, J.; Morris, J. T.; Kelly, M.

2014-12-01

Tidal wetland ecosystems are dynamic coastal habitats that, in California, often occur at the complex nexus of aquatic environments, diked and leveed baylands, and modified upland habitat. Because of their prime location and rich peat soil, many wetlands have been reduced, degraded, and/or destroyed, and yet their important role in carbon sequestration, nutrient and sediment filtering, and as habitat requires us to further examine their sustainability in light of predicted climate change. Predictions of climate change effects for the San Francisco Bay Estuary present a future with reduced summer freshwater input and increased sea levels. We examined the applicability and accuracy of the Marsh Equilibrium Model (MEM), a zero-dimensional model that models organic and inorganic accretion rates under a given rate of sea-level rise. MEM was calibrated using data collected from salt and brackish marshes in the San Francisco Bay Estuary to examine wetland resiliency under a range of sea-level rise and suspended sediment concentration scenarios. At sea-level rise rates 100 cm/century and lower, wetlands remained vegetated. Once sea levels rise above 100 cm, marshes begin to lose ability to maintain elevation, and the presence of adjacent upland habitat becomes increasingly important for marsh migration. The negative effects of sea-level rise on elevations were compounded as suspended sediment concentrations decreased. Results from this study emphasize that the wetland landscape in the bay is threatened with rising sea levels, and there are a limited number of wetlands that will be able to migrate to higher ground as sea levels rise.

Importance of flexure in response to sedimentation and erosion along the US Atlantic passive margin in reconciling sea level change and paleoshorelines

NASA Astrophysics Data System (ADS)

Moucha, R.; Ruetenik, G.; de Boer, B.

2017-12-01

Reconciling elevations of paleoshorelines along the US Atlantic passive margin with estimates of eustatic sea level have long posed to be a challenge. Discrepancies between shoreline elevation and sea level have been attributed to combinations of tectonics, glacial isostatic adjustment, mantle convection, gravitation and/or errors, for example, in the inference of eustatic sea level from the marine 18O record. Herein we present a numerical model of landscape evolution combined with sea level change and solid Earth deformations to demonstrate the importance of flexural effects in response to erosion and sedimentation along the US Atlantic passive margin. We quantify these effects using two different temporal models. One reconciles the Orangeburg scarp, a well-documented 3.5 million-year-old mid-Pliocene shoreline, with a 15 m mid-Pliocene sea level above present-day (Moucha and Ruetenik, 2017). The other model focuses on the evolution of the South Carolina and northern Georgia margin since MIS 11 ( 400 Ka) using a fully coupled ice sheet, sea level and solid Earth model (de Boer et al, 2014) while relating our results to a series of enigmatic sea level high stand markers. de Boer, B., Stocci, P., and van de Wal, R. (2014). A fully coupled 3-d ice-sheet-sea-level model: algorithm and applications. Geoscientific Model Development, 7:2141-2156. Moucha, R. and Ruetenik, G. A. (2017). Interplay between dynamic topography and flexure along the US Atlantic passive margin: Insights from landscape evolution modeling. Global and Planetary Change, 149: 72-78

Keeping your seed head above water - EPA's research on the effects of sea level rise on sea grasses and emergent marshes in the Pacific Northwest

EPA Science Inventory

Global climate change, including sea-level rise (SLR), will have profound effects on estuarine fish, shellfish, and wildlife populations and their habitats. To develop an understanding of these potential impacts, the U.S. EPA at Newport, Oregon is participating in a joint researc...

75 FR 1803 - Lower Florida Keys Refuges, Monroe County, FL

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-13

... fully assessed and the effect of climate change (e.g., sea level rise) is not known. We would protect... (e.g., hurricanes, wildfire) and global climate change, particularly sea level rise. Current ongoing... evaluate the potential impacts of sea level rise on the ecology of wading birds. Since a primary purpose of...

Measurement of gravitational time dilation: An undergraduate research project

NASA Astrophysics Data System (ADS)

Burns, M. Shane; Leveille, Michael D.; Dominguez, Armand R.; Gebhard, Brian B.; Huestis, Samuel E.; Steele, Jeffrey; Patterson, Brian; Sell, Jerry F.; Serna, Mario; Gearba, M. Alina; Olesen, Robert; O'Shea, Patrick; Schiller, Jonathan

2017-10-01

General relativity predicts that clocks run more slowly near massive objects. The effect is small—a clock at sea level lags behind one 1000 m above sea level by only 9.4 ns/day. Here, we demonstrate that a measurement of this effect can be done by undergraduate students. Our paper describes an experiment conducted by undergraduate researchers at Colorado College and the United States Air Force Academy to measure gravitational time dilation. The measurement was done by comparing the signals generated by a GPS frequency standard (sea-level time) to a Cs-beam frequency standard at seven different altitudes above sea level. We found that our measurements are consistent with the predictions of general relativity.

Sea Level Changes: Determination and Effects

NASA Astrophysics Data System (ADS)

Woodworth, P. L.; Pugh, D. T.; DeRonde, J. G.; Warrick, R. G.; Hannah, J.

The measurement of sea level is of fundamental importance to a wide range of research in climatology, oceanography, geology and geodesy. This volume attempts to cover many aspects of the field. The volume opens with a description by Bolduc and Murty of one of the products stemming from the development of tide gauge networks in the northern and tropical Atlantic. This work is relevant to the growth of the Global Sea Level Observing System (GLOSS), the main goal of which is to provide the world with an efficient, coherent sea level monitoring system for océanographie and climatological research. The subsequent four papers present results from the analysis of existing tide gauge data, including those datasets available from the Permanent Service for Mean Sea Level and the TOGA Sea Level Center. Two of the four, by Wroblewski and by Pasaric and Orlic, are concerned with European sea level changes, while Yu Jiye et al. discuss inter-annual changes in the Pacific, and Wang Baocan et al. describe variability in the Changjiang estuary in China. The papers by El- Abd and A wad, on Red Sea levels, are the only contributions to the volume from the large research community of geologists concerned with sea level changes.

Effects of Sediment Loading in Northern Europe During the Last Glacial

NASA Astrophysics Data System (ADS)

van der Wal, W.; IJpelaar, M.

2014-12-01

Over the years the framework of GIA modelling has been subject to continuous improvements, e.g. the addition of time dependent coastal margins and rotational feedback. The latest addition to this framework is the incorporation of sediment as a time-varying surface load while accounting for sea-level variations associated with the sediment transport (Dalca et al., GJI 2013). The effects of sediment loading during a glacial cycle have not been extensively investigated even though it is known that large sediment transport took place, for example in the Barents Sea region and Fennoscandia. This study investigates the effect of sediment transport on relative sea level change and present-day rates of gravity and vertical deformation in those regions. While the ice sheet history during the last glacial period has been modelled extensively there are no full-scale models of paleo-erosion and -deposition rates for regions such as Fennoscandia. Here we create end-member paleo-sedimentary models by combining geological observations of continuous erosion and deposition and large scale failure events. These models, in combination with the ICE-5G ice sheet history, serve as an input for a GIA model for a spherically symmetric incompressible Earth with the full sea-level equation. The results from this model, i.e. (rates of) relative sea level change and crustal deformation, are obtained for different viscosity models fitting best with the local rheology of Fennoscandia. By comparing GPS measurements, GRACE observations and relative sea level records with these modelled predictions the effects of sedimentary isostasy in the Fennoscandian region are studied. The sediment load does not significantly affect the modelled relative sea level curves, nor vertical deformation rates at the location of GPS measurements. However, gravity rates over the Barents Sea region are influenced significantly

Coastal vulnerability assessment of Dry Tortugas National Park (DRTO) to sea-level rise

USGS Publications Warehouse

Pendleton, Elizabeth A.; Thieler, E. Robert; Williams, S. Jeffress

2005-01-01

A coastal vulnerability index (CVI) was used to map the relative vulnerability of the coast to future sea-level rise within Dry Tortugas National Park in Florida. The CVI ranks the following in terms of their physical contribution to sea-level rise-related coastal change: geomorphology, regional coastal slope, rate of relative sea-level rise, historical shoreline change rates, mean tidal range and mean significant wave height. The rankings for each input variable were combined and an index value calculated for 1-minute grid cells covering the park. The CVI highlights those regions where the physical effects of sea-level rise might be the greatest. This approach combines the coastal system's susceptibility to change with its natural ability to adapt to changing environmental conditions, yielding a quantitative, although relative, measure of the park's natural vulnerability to the effects of sea-level rise. The CVI provides an objective technique for evaluation and long-term planning by scientists and park managers. Dry Tortugas National Park (DRTO) consists of relatively stable to washover-dominated portions of carbonate beach and man-made fortification. The areas within Dry Tortugas that are likely to be most vulnerable to sea-level rise are those with the highest rates of shoreline erosion and the highest wave energy.

Coastal vulnerability assessment of Cape Hatteras National Seashore (CAHA) to sea-level rise

USGS Publications Warehouse

Pendleton, Elizabeth A.; Theiler, E. Robert; Williams, S. Jeffress

2005-01-01

A coastal vulnerability index (CVI) was used to map the relative vulnerability of the coast to future sea-level rise within Cape Hatteras National Seashore (CAHA) in North Carolina. The CVI ranks the following in terms of their physical contribution to sea-level rise-related coastal change: geomorphology, regional coastal slope, rate of relative sea-level rise, historical shoreline change rates, mean tidal range, and mean significant wave height. The rankings for each variable were combined and an index value was calculated for 1-minute grid cells covering the park. The CVI highlights those regions where the physical effects of sea-level rise might be the greatest. This approach combines the coastal system's susceptibility to change with its natural ability to adapt to changing environmental conditions, yielding a quantitative, although relative, measure of the park's natural vulnerability to the effects of sea-level rise. The CVI provides an objective technique for evaluation and long-term planning by scientists and park managers. Cape Hatteras National Seashore consists of stable and washover dominated segments of barrier beach backed by wetland and marsh. The areas within Cape Hatteras that are likely to be most vulnerable to sea-level rise are those with the highest occurrence of overwash and the highest rates of shoreline change.

Coastal Vulnerability Assessment of Padre Island National Seashore (PAIS) to Sea-Level Rise

USGS Publications Warehouse

Pendleton, Elizabeth A.; Thieler, E. Robert; Williams, S. Jeffress; Beavers, Rebecca S.

2004-01-01

A coastal vulnerability index (CVI) was used to map the relative vulnerability of the coast to future sea-level rise within Padre Island National Seashore in Texas. The CVI ranks the following in terms of their physical contribution to sea-level rise-related coastal change: geomorphology, regional coastal slope, rate of relative sea-level rise, shoreline change rates, mean tidal range and mean significant wave height. The rankings for each variable were combined and an index value calculated for 1-minute grid cells covering the park. The CVI highlights those regions where the physical effects of sea-level rise might be the greatest. This approach combines the coastal system's susceptibility to change with its natural ability to adapt to changing environmental conditions, yielding a quantitative, although relative, measure of the park's natural vulnerability to the effects of sea-level rise. The CVI provides an objective technique for evaluation and long-term planning by scientists and park managers. Padre Island National Seashore consists of stable to washover dominated portions of barrier beach backed by wetland, marsh, tidal flat, or grassland. The areas within Padre that are likely to be most vulnerable to sea-level rise are those with the highest occurrence of overwash and the highest rates of shoreline change.

Fingerprints of Sea Level Rise on Changing Tides in the Chesapeake and Delaware Bays

NASA Astrophysics Data System (ADS)

Ross, Andrew C.; Najjar, Raymond G.; Li, Ming; Lee, Serena Blyth; Zhang, Fan; Liu, Wei

2017-10-01

Secular tidal trends are present in many tide gauge records, but their causes are often unclear. This study examines trends in tides over the last century in the Chesapeake and Delaware Bays. Statistical models show negative M2 amplitude trends at the mouths of both bays, while some upstream locations have insignificant or positive trends. To determine whether sea level rise is responsible for these trends, we include a term for mean sea level in the statistical models and compare the results with predictions from numerical and analytical models. The observed and predicted sensitivities of M2 amplitude and phase to mean sea level are similar, although the numerical model amplitude is less sensitive to sea level. The sensitivity occurs as a result of strengthening and shifting of the amphidromic system in the Chesapeake Bay and decreasing frictional effects and increasing convergence in the Delaware Bay. After accounting for the effect of sea level, significant negative background M2 and S2 amplitude trends are present; these trends may be related to other factors such as dredging, tide gauge errors, or river discharge. Projected changes in tidal amplitudes due to sea level rise over the 21st century are substantial in some areas, but depend significantly on modeling assumptions.

Committed sea-level rise under the Paris Agreement and the legacy of delayed mitigation action.

PubMed

Mengel, Matthias; Nauels, Alexander; Rogelj, Joeri; Schleussner, Carl-Friedrich

2018-02-20

Sea-level rise is a major consequence of climate change that will continue long after emissions of greenhouse gases have stopped. The 2015 Paris Agreement aims at reducing climate-related risks by reducing greenhouse gas emissions to net zero and limiting global-mean temperature increase. Here we quantify the effect of these constraints on global sea-level rise until 2300, including Antarctic ice-sheet instabilities. We estimate median sea-level rise between 0.7 and 1.2 m, if net-zero greenhouse gas emissions are sustained until 2300, varying with the pathway of emissions during this century. Temperature stabilization below 2 °C is insufficient to hold median sea-level rise until 2300 below 1.5 m. We find that each 5-year delay in near-term peaking of CO 2 emissions increases median year 2300 sea-level rise estimates by ca. 0.2 m, and extreme sea-level rise estimates at the 95th percentile by up to 1 m. Our results underline the importance of near-term mitigation action for limiting long-term sea-level rise risks.

The sleep of elite athletes at sea level and high altitude: a comparison of sea-level natives and high-altitude natives (ISA3600)

PubMed Central

Roach, Gregory D; Schmidt, Walter F; Aughey, Robert J; Bourdon, Pitre C; Soria, Rudy; Claros, Jesus C Jimenez; Garvican-Lewis, Laura A; Buchheit, Martin; Simpson, Ben M; Hammond, Kristal; Kley, Marlen; Wachsmuth, Nadine; Gore, Christopher J; Sargent, Charli

2013-01-01

Background Altitude exposure causes acute sleep disruption in non-athletes, but little is known about its effects in elite athletes. The aim of this study was to examine the effects of altitude on two groups of elite athletes, that is, sea-level natives and high-altitude natives. Methods Sea-level natives were members of the Australian under-17 soccer team (n=14). High-altitude natives were members of a Bolivian under-20 club team (n=12). Teams participated in an 18-day (19 nights) training camp in Bolivia, with 6 nights at near sea level in Santa Cruz (430 m) and 13 nights at high altitude in La Paz (3600 m). Sleep was assessed on every day/night using activity monitors. Results The Australians’ sleep was shorter, and of poorer quality, on the first night at altitude compared with sea level. Sleep quality returned to normal by the end of the first week at altitude, but sleep quantity had still not stabilised at its normal level after 2 weeks. The quantity and quality of sleep obtained by the Bolivians was similar, or greater, on all nights at altitude compared with sea level. The Australians tended to obtain more sleep than the Bolivians at sea level and altitude, but the quality of the Bolivians’ sleep tended to be better than that of the Australians at altitude. Conclusions Exposure to high altitude causes acute and chronic disruption to the sleep of elite athletes who are sea-level natives, but it does not affect the sleep of elite athletes who are high-altitude natives. PMID:24282197

The sleep of elite athletes at sea level and high altitude: a comparison of sea-level natives and high-altitude natives (ISA3600).

PubMed

Roach, Gregory D; Schmidt, Walter F; Aughey, Robert J; Bourdon, Pitre C; Soria, Rudy; Claros, Jesus C Jimenez; Garvican-Lewis, Laura A; Buchheit, Martin; Simpson, Ben M; Hammond, Kristal; Kley, Marlen; Wachsmuth, Nadine; Gore, Christopher J; Sargent, Charli

2013-12-01

Altitude exposure causes acute sleep disruption in non-athletes, but little is known about its effects in elite athletes. The aim of this study was to examine the effects of altitude on two groups of elite athletes, that is, sea-level natives and high-altitude natives. Sea-level natives were members of the Australian under-17 soccer team (n=14). High-altitude natives were members of a Bolivian under-20 club team (n=12). Teams participated in an 18-day (19 nights) training camp in Bolivia, with 6 nights at near sea level in Santa Cruz (430 m) and 13 nights at high altitude in La Paz (3600 m). Sleep was assessed on every day/night using activity monitors. The Australians' sleep was shorter, and of poorer quality, on the first night at altitude compared with sea level. Sleep quality returned to normal by the end of the first week at altitude, but sleep quantity had still not stabilised at its normal level after 2 weeks. The quantity and quality of sleep obtained by the Bolivians was similar, or greater, on all nights at altitude compared with sea level. The Australians tended to obtain more sleep than the Bolivians at sea level and altitude, but the quality of the Bolivians' sleep tended to be better than that of the Australians at altitude. Exposure to high altitude causes acute and chronic disruption to the sleep of elite athletes who are sea-level natives, but it does not affect the sleep of elite athletes who are high-altitude natives.

Spatial Patterns of Sea Level Variability Associated with Natural Internal Climate Modes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Han, Weiqing; Meehl, Gerald A.; Stammer, Detlef

Sea level rise (SLR) can exert significant stress on highly populated coastal societies and low-lying island countries around the world. Because of this, there is huge societal demand for improved decadal predictions and future projections of SLR, particularly on a local scale along coastlines. Regionally, sea level variations can deviate considerably from the global mean due to various geophysical processes. These include changes of ocean circulations, which partially can be attributed to natural, internal modes of variability in the complex Earth’s climate system. Anthropogenic influence may also contribute to regional sea level variations. Separating the effects of natural climate modesmore » and anthropogenic forcing, however, remains a challenge and requires identification of the imprint of specific climate modes in observed sea level change patterns. In this article, we review our current state of knowledge about spatial patterns of sea level variability associated with natural climate modes on interannual-to-multidecadal timescales, with particular focus on decadal-to-multidecadal variability. Relevant climate modes and our current state of understanding their associated sea level patterns and driving mechanisms are elaborated separately for the Pacific, the Indian, the Atlantic, and the Arctic and Southern Oceans. We also discuss the issues, challenges and future outlooks for understanding the regional sea level patterns associated with climate modes. Effects of these internal modes have to be taken into account in order to achieve more reliable near-term predictions and future projections of regional SLR.« less

Spatial Patterns of Sea Level Variability Associated with Natural Internal Climate Modes

DOE PAGES

Han, Weiqing; Meehl, Gerald A.; Stammer, Detlef; ...

2016-10-04

Sea level rise (SLR) can exert significant stress on highly populated coastal societies and low-lying island countries around the world. Because of this, there is huge societal demand for improved decadal predictions and future projections of SLR, particularly on a local scale along coastlines. Regionally, sea level variations can deviate considerably from the global mean due to various geophysical processes. These include changes of ocean circulations, which partially can be attributed to natural, internal modes of variability in the complex Earth’s climate system. Anthropogenic influence may also contribute to regional sea level variations. Separating the effects of natural climate modesmore » and anthropogenic forcing, however, remains a challenge and requires identification of the imprint of specific climate modes in observed sea level change patterns. In this article, we review our current state of knowledge about spatial patterns of sea level variability associated with natural climate modes on interannual-to-multidecadal timescales, with particular focus on decadal-to-multidecadal variability. Relevant climate modes and our current state of understanding their associated sea level patterns and driving mechanisms are elaborated separately for the Pacific, the Indian, the Atlantic, and the Arctic and Southern Oceans. We also discuss the issues, challenges and future outlooks for understanding the regional sea level patterns associated with climate modes. Effects of these internal modes have to be taken into account in order to achieve more reliable near-term predictions and future projections of regional SLR.« less

Spatial Patterns of Sea Level Variability Associated with Natural Internal Climate Modes

NASA Astrophysics Data System (ADS)

Han, Weiqing; Meehl, Gerald A.; Stammer, Detlef; Hu, Aixue; Hamlington, Benjamin; Kenigson, Jessica; Palanisamy, Hindumathi; Thompson, Philip

2017-01-01

Sea level rise (SLR) can exert significant stress on highly populated coastal societies and low-lying island countries around the world. Because of this, there is huge societal demand for improved decadal predictions and future projections of SLR, particularly on a local scale along coastlines. Regionally, sea level variations can deviate considerably from the global mean due to various geophysical processes. These include changes of ocean circulations, which partially can be attributed to natural, internal modes of variability in the complex Earth's climate system. Anthropogenic influence may also contribute to regional sea level variations. Separating the effects of natural climate modes and anthropogenic forcing, however, remains a challenge and requires identification of the imprint of specific climate modes in observed sea level change patterns. In this paper, we review our current state of knowledge about spatial patterns of sea level variability associated with natural climate modes on interannual-to-multidecadal timescales, with particular focus on decadal-to-multidecadal variability. Relevant climate modes and our current state of understanding their associated sea level patterns and driving mechanisms are elaborated separately for the Pacific, the Indian, the Atlantic, and the Arctic and Southern Oceans. We also discuss the issues, challenges and future outlooks for understanding the regional sea level patterns associated with climate modes. Effects of these internal modes have to be taken into account in order to achieve more reliable near-term predictions and future projections of regional SLR.

Evaluating coastal landscape response to sea-level rise in the northeastern United States: approach and methods

USGS Publications Warehouse

Lentz, Erika E.; Stippa, Sawyer R.; Thieler, E. Robert; Plant, Nathaniel G.; Gesch, Dean B.; Horton, Radley M.

2014-02-13

The U.S. Geological Survey is examining effects of future sea-level rise on the coastal landscape from Maine to Virginia by producing spatially explicit, probabilistic predictions using sea-level projections, vertical land movement rates (due to isostacy), elevation data, and land-cover data. Sea-level-rise scenarios used as model inputs are generated by using multiple sources of information, including Coupled Model Intercomparison Project Phase 5 models following representative concentration pathways 4.5 and 8.5 in the Intergovernmental Panel on Climate Change Fifth Assessment Report. A Bayesian network is used to develop a predictive coastal response model that integrates the sea-level, elevation, and land-cover data with assigned probabilities that account for interactions with coastal geomorphology as well as the corresponding ecological and societal systems it supports. The effects of sea-level rise are presented as (1) level of landscape submergence and (2) coastal response type characterized as either static (that is, inundation) or dynamic (that is, landform or landscape change). Results are produced at a spatial scale of 30 meters for four decades (the 2020s, 2030s, 2050s, and 2080s). The probabilistic predictions can be applied to landscape management decisions based on sea-level-rise effects as well as on assessments of the prediction uncertainty and need for improved data or fundamental understanding. This report describes the methods used to produce predictions, including information on input datasets; the modeling approach; model outputs; data-quality-control procedures; and information on how to access the data and metadata online.

Evaluating Coastal Landscape Response to Sea-Level Rise in the Northeastern United States - Approach and Methods

NASA Technical Reports Server (NTRS)

Lentz, Erika E.; Stippa, Sawyer R.; Thieler, E. Robert; Plant, Nathaniel G.; Gesch, Dean B.; Horton, Radley M.

2015-01-01

The U.S. Geological Survey is examining effects of future sea-level rise on the coastal landscape from Maine to Virginia by producing spatially explicit, probabilistic predictions using sea-level projections, vertical land movement rates (due to isostacy), elevation data, and land-cover data. Sea-level-rise scenarios used as model inputs are generated by using multiple sources of information, including Coupled Model Intercomparison Project Phase 5 models following representative concentration pathways 4.5 and 8.5 in the Intergovernmental Panel on Climate Change Fifth Assessment Report. A Bayesian network is used to develop a predictive coastal response model that integrates the sea-level, elevation, and land-cover data with assigned probabilities that account for interactions with coastal geomorphology as well as the corresponding ecological and societal systems it supports. The effects of sea-level rise are presented as (1) level of landscape submergence and (2) coastal response type characterized as either static (that is, inundation) or dynamic (that is, landform or landscape change). Results are produced at a spatial scale of 30 meters for four decades (the 2020s, 2030s, 2050s, and 2080s). The probabilistic predictions can be applied to landscape management decisions based on sea-level-rise effects as well as on assessments of the prediction uncertainty and need for improved data or fundamental understanding. This report describes the methods used to produce predictions, including information on input datasets; the modeling approach; model outputs; data-quality-control procedures; and information on how to access the data and metadata online.

Tidal wetland stability in the face of human impacts and sea-level rise.

PubMed

Kirwan, Matthew L; Megonigal, J Patrick

2013-12-05

Coastal populations and wetlands have been intertwined for centuries, whereby humans both influence and depend on the extensive ecosystem services that wetlands provide. Although coastal wetlands have long been considered vulnerable to sea-level rise, recent work has identified fascinating feedbacks between plant growth and geomorphology that allow wetlands to actively resist the deleterious effects of sea-level rise. Humans alter the strength of these feedbacks by changing the climate, nutrient inputs, sediment delivery and subsidence rates. Whether wetlands continue to survive sea-level rise depends largely on how human impacts interact with rapid sea-level rise, and socio-economic factors that influence transgression into adjacent uplands.

Effects of sea-level rise and pumpage elimination on saltwater intrusion in the Hilton Head Island area, South Carolina, 2004-2104

USGS Publications Warehouse

Payne, Dorothy F.

2010-01-01

Saltwater intrusion of the Upper Floridan aquifer has been observed in the Hilton Head area, South Carolina since the late 1970s and currently affects freshwater supply. Rising sea level in the Hilton Head Island area may contribute to the occurrence of and affect the rate of saltwater intrusion into the Upper Floridan aquifer by increasing the hydraulic gradient and by inundating an increasing area with saltwater, which may then migrate downward into geologic units that presently contain freshwater. Rising sea level may offset any beneficial results from reductions in groundwater pumpage, and thus needs to be considered in groundwater-management decisions. A variable-density groundwater flow and transport model was modified from a previously existing model to simulate the effects of sea-level rise in the Hilton Head Island area. Specifically, the model was used to (1) simulate trends of saltwater intrusion from predevelopment to the present day (1885-2004) and evaluate the conceptual model, (2) project these trends from the present day into the future based on different potential rates of sea-level change, and (3) evaluate the relative influences of pumpage and sea-level rise on saltwater intrusion. Four scenarios were simulated for 2004-2104: (1) continuation of the estimated sea-level rise rate over the last century, (2) a doubling of the sea-level rise, (3) a cessation of sea-level rise, and (4) continuation of the rate over the last century coupled with an elimination of all pumpage. Results show that, if present-day (year 2004) pumping conditions are maintained, the extent of saltwater in the Upper Floridan aquifer will increase, whether or not sea level continues to rise. Furthermore, if all pumpage is eliminated and sea level continues to rise, the simulated saltwater extent in the Upper Floridan aquifer is reduced. These results indicate that pumpage is a strong driving force for simulated saltwater intrusion, more so than sea-level rise at current rates. However, results must be considered in light of limitations in the model, including, but not limited to uncertainty in field data, the conceptual model, the physical properties and representation of the hydrogeologic framework, and boundary and initial conditions, as well as uncertainty in future conditions, such as the rate of sea-level rise.

Paleocene-Eocene and Plio-Pleistocene sea-level changes as "species pumps" in Southeast Asia: Evidence from Althepus spiders.

PubMed

Li, Fengyuan; Li, Shuqiang

2018-05-17

Sea-level change has been viewed as a primary driver in the formation of biodiversity. Early studies confirmed that Plio-Pleistocene sea-level changes led to the isolation and subsequent genetic differentiation of Southeast (SE) Asian organisms over short geological timescales. However, long-time consequences of sea-level fluctuations remain unclear. Herein, we analyze the evolutionary history of Althepus (spiders) whose distribution encompasses Indo-Burma and the Sunda shelf islands to understand how sea-level changes over shallow and deep timescales effected their history. Our integrative analyses, including phylogeny, divergence times, ancestral area reconstruction and diversification dynamics, reveal an intricate pattern of diversification, probably triggered by sea-level fluctuations during the Paleocene-Eocene and Plio-Pleistocene. The timing of one early divergence between the Indo-Burmese and Sundaic species coincides with late Paleocene and early Eocene high global sea levels, which induced the formation of inland seaways in the Thai-Malay Peninsula. Subsequent lowered sea levels could have provided a land bridge for its dispersal colonization across the Isthmus of Kra. Analyses suggest that Plio-Pleistocene sea-level rises contributed to recent divergence of many species. Thus, our findings cannot reject the hypothesis that sea-level changes during the Paleocene-Eocene and Plio-Pleistocene played a major role in generating biodiversity in SE Asia; sea-level changes can act as "species pumps". Copyright © 2018 Elsevier Inc. All rights reserved.

Preparing for Sea-level Rise: Conflicts and Opportunities in Coastal Wetlands Coexisting with Infrastructure

NASA Astrophysics Data System (ADS)

Rodriguez, J. F.; Saco, P. M.; Sandi, S. G.; Saintilan, N.; Riccardi, G.

2017-12-01

Even though on a large scale the sustainability and resilience of coastal wetlands to sea-level rise depends on the slope of the landscape and a balance between the rates of soil accretion and the sea-level rise, local man-made flow disturbances can have comparable effects. Coastal infrastructure controlling flow in the wetlands can pose an additional constraint on the adaptive capacity of these ecosystems, but can also present opportunities for targeted flow management to increase their resilience. Coastal wetlands in SE Australia are heavily managed and typically present infrastructure including flow control devices. How these flow control structures are operated respond to different ecological conservation objectives (i.e. bird, frog or fish habitat) that can sometimes be mutually exclusive. For example, promoting mangrove establishment to enhance fish habitat results in saltmarsh decline thus affecting bird habitat. Moreover, sea-level rise will change hydraulic conditions in wetlands and may result in some flow control structures and strategies becoming obsolete or even counterproductive. In order to address these problems and in support of future management of flows in coastal wetlands, we have developed a predictive tool for long-term wetland evolution that incorporates the effects of infrastructure and other perturbations to the tidal flow within the wetland (i.e. vegetation resistance) and determines how these flow conditions affect vegetation establishment and survival. We use the model to support management and analyse different scenarios of sea-level rise and flow control measures aimed at preserving bird habitat. Our results show that sea-level rise affects the efficiency of management measures and in some cases may completely override their effect. It also shows the potential of targeted flow management to compensate for the effects of sea-level rise.

Intermittent sea-level acceleration

NASA Astrophysics Data System (ADS)

Olivieri, M.; Spada, G.

2013-10-01

Using instrumental observations from the Permanent Service for Mean Sea Level (PSMSL), we provide a new assessment of the global sea-level acceleration for the last ~ 2 centuries (1820-2010). Our results, obtained by a stack of tide gauge time series, confirm the existence of a global sea-level acceleration (GSLA) and, coherently with independent assessments so far, they point to a value close to 0.01 mm/yr2. However, differently from previous studies, we discuss how change points or abrupt inflections in individual sea-level time series have contributed to the GSLA. Our analysis, based on methods borrowed from econometrics, suggests the existence of two distinct driving mechanisms for the GSLA, both involving a minority of tide gauges globally. The first effectively implies a gradual increase in the rate of sea-level rise at individual tide gauges, while the second is manifest through a sequence of catastrophic variations of the sea-level trend. These occurred intermittently since the end of the 19th century and became more frequent during the last four decades.

How will coastal sea level respond to changes in natural and anthropogenic forcings by 2100?

NASA Astrophysics Data System (ADS)

Jevrejeva, S.; Moore, J.; Grinsted, A.

2010-12-01

Sea level rise is perhaps the most damaging repercussion of global warming, as 150 million people live less than one meter above current high tides .Using an inverse statistical model we examine potential response in coastal sea level to the changes in natural and anthropogenic forcings by 2100. With six IPCC radiative forcing scenarios we estimate sea level rise of 0.6-1.6 m, with confidence limits of 0.59 m and 1.8 m. Projected impacts of solar and volcanic radiative forcings account only for, at maximum, 5% of total sea level rise, with anthropogenic greenhouse gasses being the dominant forcing. As alternatives to the IPCC projections, even the most intense century of volcanic forcing from the past 1000 years would result in 10-15 cm potential reduction of sea level rise. Stratospheric injections of SO2 equivalent to a Pinatubo eruption every 4 years would effectively just delay sea level rise by 12 -20 years.

Protective effects of a novel sea buckthorn wine on oxidative stress and hypercholesterolemia.

PubMed

Negi, Bharti; Kaur, Rajdeep; Dey, Gargi

2013-02-01

We developed a novel sea buckthorn wine containing significant in vitro free radical-scavenging activity. High-performance liquid chromatographic analysis of the sea buckthorn wine revealed that it contains high rutin, myricetin and quercetin levels compared to Cabernet Shiraz wine. In this study, we evaluated the protective effects of sea buckthorn wine against phorone-induced oxidative stress and high-cholesterol diet induced hypercholesterolemia in male LACA mice. Oral administration of sea buckthorn wine increased the redox ratio accompanied by reduction of oxidized glutathione levels leading to attenuation of phorone-induced oxidative stress. Furthermore, the sea buckthorn wine supplementation reduced hepatic lipid peroxidation and increased the superoxide dismutase activity indicating improved resistance to oxidative stress. In addition, high-cholesterol-fed mice administered with sea buckthorn wine exhibited a 197% increase in the HDL-C/LDL-C ratio compared to high-cholesterol diet treated mice. These studies provide important evidence that sea buckthorn wine exerts protective effects against oxidative stress and hypercholesterolemia.

How Do River Meanders Change with Sea Level Rise and Fall?

NASA Astrophysics Data System (ADS)

Scamardo, J. E.; Kim, W.

2016-12-01

River meander patterns are controlled by numerous factors, including variations in water discharge, sediment input, and base level. However, the effect of sea level rise and fall on meandering rivers has not been thoroughly quantified. This study examines geomorphic changes to meandering rivers as a result of sea level rise and fall. Twenty experimental runs using coarse-grained walnut shell sediment (D50= 500 microns) in a flume tank (2.4m x 0.6m x 0.1m) tested the optimal initial conditions for creating meandering rivers in a laboratory setting as well as variations in base level rise and fall rates. Geomorphic changes were recorded by camera images every 20 seconds for a duration of 4 hours per experiment. Seventeen experiments tested the effects of changes in initial base levels, water discharge between 200 and 400 mL/min, and sediment to water input ratios between 1:1000 and 1:250 while measuring sinuosity, channel geometry, and the timescale of the channel to reach a stable form. Sinuosity and channel activity increased with increasing water discharge, initial base level, and the sediment to water ratio to a point after which the activity decreased with increasing sediment input. Base-level change experiments used initial conditions of 400 mL/min, a 1:750 sediment to water input ratio, and a 6 cm initial base-level to induce river meanders for the initial 2 hours before base-level change occurred. Three separate experiments investigated the effects of increasing rates of sea level change: 0.07 cm/min, 0.1 cm/min, and 0.2 cm/min. Experimental sea level was decreased constantly from a high-stand of 6 cm to a low-stand of 2 cm back to the high-stand base-level in each experiment. The rates of change in the experiments scale roughly from central to glacial cycles. In all three experiments, sea level fall induced meander cut-off while sea level rise prompted greater rates of meander bend erosion and meander growth. Sinuosity increased by 12%, 13.5%, and 24%, respectively in the three experiments, with most sinuosity changes occurring in the downstream reach of the channel. These experiments could provide insight into long term effects of sea level change on modern meandering fluvial systems as well as provide a key to interpreting past fluvial changes in the stratigraphic record.

Projecting Future Sea Level Rise for Water Resources Planning in California

NASA Astrophysics Data System (ADS)

Anderson, J.; Kao, K.; Chung, F.

2008-12-01

Sea level rise is one of the major concerns for the management of California's water resources. Higher water levels and salinity intrusion into the Sacramento-San Joaquin Delta could affect water supplies, water quality, levee stability, and aquatic and terrestrial flora and fauna species and their habitat. Over the 20th century, sea levels near San Francisco Bay increased by over 0.6ft. Some tidal gauge and satellite data indicate that rates of sea level rise are accelerating. Sea levels are expected to continue to rise due to increasing air temperatures causing thermal expansion of the ocean and melting of land-based ice such as ice on Greenland and in southeastern Alaska. For water planners, two related questions are raised on the uncertainty of future sea levels. First, what is the expected sea level at a specific point in time in the future, e.g., what is the expected sea level in 2050? Second, what is the expected point of time in the future when sea levels will exceed a certain height, e.g., what is the expected range of time when the sea level rises by one foot? To address these two types of questions, two factors are considered: (1) long term sea level rise trend, and (2) local extreme sea level fluctuations. A two-step approach will be used to develop sea level rise projection guidelines for decision making that takes both of these factors into account. The first step is developing global sea level rise probability distributions for the long term trends. The second step will extend the approach to take into account the effects of local astronomical tides, changes in atmospheric pressure, wind stress, floods, and the El Niño/Southern Oscillation. In this paper, the development of the first step approach is presented. To project the long term sea level rise trend, one option is to extend the current rate of sea level rise into the future. However, since recent data indicate rates of sea level rise are accelerating, methods for estimating sea level rise that account for this acceleration are needed. One such method is an empirical relationship between air temperatures and global sea levels. The air temperature-sea level rise relationship was applied to the 12 climate change projections selected by the California Climate Action Team to estimate future sea levels. The 95% confidence level developed from the historical data was extrapolated to estimate the uncertainties in the future projections. To create sea level rise trend probability distributions, a lognormal probability distribution and a generalized extreme value probability distribution are used. Parameter estimations for these distributions are subjective and inevitably involve uncertainties, which will be improved as more research is conducted in this area.

Influence of climate change and trophic coupling across four trophic levels in the Celtic Sea.

PubMed

Lauria, Valentina; Attrill, Martin J; Pinnegar, John K; Brown, Andrew; Edwards, Martin; Votier, Stephen C

2012-01-01

Climate change has had profound effects upon marine ecosystems, impacting across all trophic levels from plankton to apex predators. Determining the impacts of climate change on marine ecosystems requires understanding the direct effects on all trophic levels as well as indirect effects mediated by trophic coupling. The aim of this study was to investigate the effects of climate change on the pelagic food web in the Celtic Sea, a productive shelf region in the Northeast Atlantic. Using long-term data, we examined possible direct and indirect 'bottom-up' climate effects across four trophic levels: phytoplankton, zooplankton, mid-trophic level fish and seabirds. During the period 1986-2007, although there was no temporal trend in the North Atlantic Oscillation index (NAO), the decadal mean Sea Surface Temperature (SST) in the Celtic Sea increased by 0.66 ± 0.02 °C. Despite this, there was only a weak signal of climate change in the Celtic Sea food web. Changes in plankton community structure were found, however this was not related to SST or NAO. A negative relationship occurred between herring abundance (0- and 1-group) and spring SST (0-group: p = 0.02, slope = -0.305 ± 0.125; 1-group: p = 0.04, slope = -0.410 ± 0.193). Seabird demographics showed complex species-specific responses. There was evidence of direct effects of spring NAO (on black-legged kittiwake population growth rate: p = 0.03, slope = 0.0314 ± 0.014) as well as indirect bottom-up effects of lagged spring SST (on razorbill breeding success: p = 0.01, slope = -0.144 ± 0.05). Negative relationships between breeding success and population growth rate of razorbills and common guillemots may be explained by interactions between mid-trophic level fish. Our findings show that the impacts of climate change on the Celtic Sea ecosystem is not as marked as in nearby regions (e.g. the North Sea), emphasizing the need for more research at regional scales.

Sensitivity analysis of hydrogeological parameters affecting groundwater storage change caused by sea level rise

NASA Astrophysics Data System (ADS)

Shin, J.; Kim, K.-H.; Lee, K.-K.

2012-04-01

Sea level rise, which is one of the representative phenomena of climate changes caused by global warming, can affect groundwater system. The rising trend of the sea level caused by the global warming is reported to be about 3 mm/year for the most recent 10 year average (IPCC, 2007). The rate of sea level rise around the Korean peninsula is reported to be 2.30±2.22 mm/yr during the 1960-1999 period (Cho, 2002) and 2.16±1.77 mm/yr (Kim et al., 2009) during the 1968-2007 period. Both of these rates are faster than the 1.8±0.5 mm/yr global average for the similar 1961-2003 period (IPCC, 2007). In this study, we analyzed changes in the groundwater environment affected by the sea level rise by using an analytical methodology. We tried to find the most effective parameters of groundwater amount change in order to estimate the change in fresh water amount in coastal groundwater. A hypothetical island model of a cylindrical shape in considered. The groundwater storage change is bi-directional as the sea level rises according to the natural and hydrogeological conditions. Analysis of the computation results shows that topographic slope and hydraulic conductivity are the most sensitive factors. The contributions of the groundwater recharge rate and the thickness of aquifer below sea level are relatively less effective. In the island with steep seashore slopes larger than 1~2 degrees or so, the storage amount of fresh water in a coastal area increases as sea level rises. On the other hand, when sea level drops, the storage amount decreases. This is because the groundwater level also rises with the rising sea level in steep seashores. For relatively flat seashores, where the slope is smaller than around 1-2 degrees, the storage amount of coastal fresh water decreases when the sea level rises because the area flooded by the rising sea water is increased. The volume of aquifer fresh water in this circumstance is greatly reduced in proportion to the flooded area with the sea level rising. Since relatively flat seashores where the slope is less than 1-2 degrees are much more common in Korea, it is expected that the quantity of fresh groundwater storage in most of the coastal region in Korea will be greatly reduced with sea level rise. Acknowledgement: This study is financially supported by BK21.

The complex reality of sea-level rise in an atoll nation

NASA Astrophysics Data System (ADS)

Donner, S. D.

2012-12-01

Sea-level rise famously poses an existential threat to island nations like Kiribati, Tuvalu and the Maldives. Yet as the global mean sea-level rises, the response of any one location at any given time will depend on the natural variability in regional sea-level and other impact of local human activities on coastal processes. As with climate warming, the state of an individual shoreline or the extent of flooding on a given day is not proof of a sea-level trend, nor is a global sea-level trend a good predictor of individual flooding or erosion events. Failure to consider the effect of natural variability and local human activity on coastal processes often leads to misattribution of flooding events and even some long-term shoreline changes to global sea level rise. Moreover, unverified attribution of individual events or changes to specific islets to sea level rise can inflame or invite scepticism of the strong scientific evidence for an accelerating increase in the global sea level due to the impacts of human activity on the climate system. This is particularly important in developing nations like Kiribati, which are depending on international financial support to adapt to rising sea levels. In this presentation, I use gauge data and examples from seven years of field work in Tarawa Atoll, the densely populated capital of Kiribati, to examine the complexity of local sea level and shoreline change in one of the world's most vulnerable countries. First, I discuss how the combination of El Nino-driven variability in sea-level and the astronomical tidal cycle leads to flooding and erosion events which can be mistaken for evidence of sea-level rise. Second, I show that human modification to shorelines has redirected sediment supply, leading, in some cases, to expansion of islets despite rising sea levels. Taken together, the analysis demonstrates the challenge of attributing particular coastal events to global mean sea-level rise and the impact on decision-making. The presentation concludes with a discussion of the implications for attribution research, discourse about sea-level rise, and adaptation planning.

Steric and mass-induced Mediterranean sea level trends from 14 years of altimetry data

NASA Astrophysics Data System (ADS)

Criado-Aldeanueva, Francisco; Del Río Vera, Jorge; García-Lafuente, Jesús

2008-02-01

Long-term series of almost 14 years of altimetry data (1992-2005) have been analysed along with Sea Surface Temperature (SST) and temperature and salinity profiles to investigate sea level trends over the Mediterranean Sea. Although sea level variations are mainly driven by the steric contribution, the mass-induced component plays some role in modulating its oscillation. A spatially averaged positive trend of 2.1 ± 0.6 mm/year has been observed, but a change in sign in 2001 seems to appear. Steric effects (mainly on thermal origin) account for ˜ 55% of sea level trend. Although Mediterranean Sea is a semi-enclosed basin, this value is comparable to that reported for the global ocean. Sea level rise is particularly important in the Levantine basin south of Crete with values up to 10 ± 1 mm/year. Other areas of sea level rise are localised throughout the Levantine basin and in the Adriatic and Alboran Seas, with more moderate values. Sea level drop areas are localised in the Algerian basin, between the Balearic Islands and the African coasts and, particularly, in the Ionian basin. In this area, negative trends as high as - 10 ± 0.8 mm/year are detected mainly due to the mass-induced contribution, which suggests decadal changes of surface circulation. The inferred sea level trends have been correlated with North Atlantic Oscillation (NAO) indices and a low but significant correlation has been detected between sea level in the Levantine and Balearic basins and NAO index.

Effects of climate change on water quality in the Yaquina ...

EPA Pesticide Factsheets

As part of a larger study to examine the effect of climate change (CC) on estuarine resources, we simulated the effect of rising sea level, alterations in river discharge, and increasing atmospheric temperatures on water quality in the Yaquina Estuary. Due to uncertainty in the effects of climate change, initial model simulations were performed for different steady river discharge rates that span the historical range in inflow, and for a range of increases in sea level and atmospheric temperature. Model simulations suggest that in the central portion of the estuary (19 km from mouth), a 60-cm increase in sea level will result in a 2-3 psu change in salinity across a broad range of river discharges. For the oligohaline portion of the estuary, salinity increases associated with a rise in sea level of 60 cm are only apparent at low river discharge rates (< 50 m3 s-1). Simulations suggest that the water temperatures near the mouth of the estuary will decrease due to rising sea level, while water temperatures in upriver portions of the estuary will increase due to rising atmospheric temperatures. We present results which demonstrate how the interaction of changes in river discharge, rising sea level, and atmospheric temperature associated with climate change produce non-linear patterns in the response of estuarine salinity and temperature, which vary with location inside the estuary and season. We also will discuss the importance of presenting results in a mann

Sea level variability at the coast: is it dominated by waves even at interdecadal time scales?

NASA Astrophysics Data System (ADS)

Melet, Angelique; Almar, Rafael; Meyssignac, Benoit

2017-04-01

Tide gauge records and satellite altimetry indicate that global mean sea level has risen by 16±3 cm during the 20th century. This rise is essentially due to thermal expansion of the ocean and land ice loss from glaciers and ice sheets in response to anthropogenic emissions of greenhouse gases. It is projected to continue over the 21st century and raise concerns for coastal regions. But coastal sea level variations are influenced by other processes such as tides, atmospheric surges and wave induced run-up and set-up. Here we examine the relative importance of the processes causing sea level variations at the coast over the last 23 years from observational datasets and model reanalyses focusing on coastal sites distributed along the world's coastlines for which tide gauges records are available. We show that the long term wave signal can dampen or enhance the effect of the ocean thermal expansion and land ice loss at the coast, over all time scales from subannnual to multidecadal. We estimate that the effect of waves generally explains 60%±20% of the coastal sea level variations at interannual to multidecadal time scales. In the Eastern Pacific, the wave effect dominates the total budget and counterbalances the thermal expansion of the ocean and land ice loss signals. These results highlight that the wave effect has to be taken into account in sea level predictions and projections.

An Earth's Future Special Collection: Impacts of the coastal dynamics of sea level rise on low-gradient coastal landscapes

NASA Astrophysics Data System (ADS)

Kidwell, David M.; Dietrich, J. Casey; Hagen, Scott C.; Medeiros, Stephen C.

2017-01-01

Rising sea level represents a significant threat to coastal communities and ecosystems, including altered habitats and increased vulnerability to coastal storms and recurrent inundation. This threat is exemplified in the northern Gulf of Mexico, where low topography, marshes, and a prevalence of tropical storms have resulted in extensive coastal impacts. The ability to facilitate adaptation and mitigation measures relies, in part, on the development of robust predictive capabilities that incorporate complex biological processes with physical dynamics. Initiated in 2010, the 6-year Ecological Effects of Sea Level Rise—Northern Gulf of Mexico project applied a transdisciplinary science approach to develop a suite of integrated modeling platforms informed by empirical data that are capable of evaluating a range of climate change scenarios. This special issue highlights resultant integrated models focused on tidal hydrodynamics, shoreline morphology, oyster ecology, coastal wetland vulnerability, and storm surges that demonstrate the need for dynamic models to incorporate feedbacks among physical and biological processes in assessments of sea level rise effects on coastal systems. Effects are projected to be significant, spatially variable and nonlinear relative to sea level rise rates. Scenarios of higher sea level rise rates are projected to exceed thresholds of wetland sustainability, and many regions will experience enhanced storm surges. Influenced by an extensive collaborative stakeholder engagement process, these assessments on the coastal dynamics of sea level rise provide a strong foundation for resilience measures in the northern Gulf of Mexico and a transferable approach for application to other coastal regions throughout the world.

GIS analysis of effects of future Baltic sea level rise on the island of Gotland, Sweden

NASA Astrophysics Data System (ADS)

Ebert, Karin; Ekstedt, Karin; Jarsjö, Jerker

2016-07-01

Future sea level rise as a consequence of global warming will affect the world's coastal regions. Even though the pace of sea level rise is not clear, the consequences will be severe and global. Commonly the effects of future sea level rise are investigated for relatively vulnerable development countries; however, a whole range of varying regions needs to be considered in order to improve the understanding of global consequences. In this paper we investigate consequences of future sea level rise along the coast of the Baltic Sea island of Gotland, Sweden, with the aim to fill knowledge gaps regarding comparatively well-suited areas in developed countries. We study both the quantity of the loss of features of infrastructure, cultural, and natural value in the case of a 2 m sea level rise of the Baltic Sea and the effects of climate change on seawater intrusion in coastal aquifers, which indirectly cause saltwater intrusion in wells. We conduct a multi-criteria risk analysis by using lidar data on land elevation and GIS-vulnerability mapping, which gives the application of distance and elevation parameters formerly unimaginable precision. We find that in case of a 2 m sea level rise, 3 % of the land area of Gotland, corresponding to 99 km2, will be inundated. The features most strongly affected are items of touristic or nature value, including camping places, shore meadows, sea stack areas, and endangered plants and species habitats. In total, 231 out of 7354 wells will be directly inundated, and the number of wells in the high-risk zone for saltwater intrusion in wells will increase considerably. Some valuable features will be irreversibly lost due to, for example, inundation of sea stacks and the passing of tipping points for seawater intrusion into coastal aquifers; others might simply be moved further inland, but this requires considerable economic means and prioritization. With nature tourism being one of the main income sources of Gotland, monitoring and planning are required to meet the changes. Seeing Gotland in a global perspective, this island shows that holistic multi-feature studies of future consequences of sea level rise are required to identify overall consequences for individual regions.

Development of a Geographic Information System (GIS) tool for the preliminary assessment of the effects of predicted sea level and tidal change on transportation infrastructure : [summary].

DOT National Transportation Integrated Search

2013-01-01

The longest record of sea levels in the Western Hemisphere began in 1846 in Key West, Florida. It shows a steady and gradually accelerating sea level rise (SLR) nine inches since 1900. The increasing rate of recent years has implications for Flor...

Developing a Learning Progression for Sea Level Rise, a Major Impact of Climate Change

ERIC Educational Resources Information Center

Breslyn, Wayne; McGinnis, J. Randy; McDonald, R. Christopher; Hestness, Emily

2016-01-01

We present research from an investigation on developing a learning progression (LP) for sea level rise (SLR), a major effect of global climate change. We began our research by drafting a hypothetical LP for sea level rise, informed by extant knowledge of the topic in the scientific community, in science education literature, and in science…

Geologic effects and coastal vulnerability to sea-level rise, erosion, and storms

USGS Publications Warehouse

Williams, S.J.; Gutierrez, B.T.; Thieler, E.R.; Pendleton, E.

2008-01-01

A combination of natural and human factors are driving coastal change and making coastal regions and populations increasingly vulnerable. Sea level, a major agent of coastal erosion, has varied greatly from -120 m below present during glacial period low-stands to + 4 to 6 m above present during interglacial warm periods. Geologic and tide gauge data show that global sea level has risen about 12 to 15 cm during the past century with satellite measurements indicating an acceleration since the early 1990s due to thermal expansion and ice-sheet melting. Land subsidence due to tectonic forces and sediment compaction in regions like the mid-Atlantic and Louisiana increase the rate of relative sea-level rise to 40 cm to 100 cm per century. Sea- level rise is predicted to accelerate significantly in the near future due to climate change, resulting in pervasive impacts to coastal regions and putting populations increasingly at risk. The full implications of climate change for coastal systems need to be understood better and long-term plans are needed to manage coasts in order to protect natural resources and mitigate the effects of sea-level rise and increased storms on human infrastructure. 

Late Quaternary variations in relative sea level due to glacial cycle polar wander

USGS Publications Warehouse

Bills, B.G.; James, T.S.

1996-01-01

Growth and decay of continental ice sheets can excite significant motion of the Earth's rotation pole and cause a complex spatio-temporal pattern of changes in relative sea level. These two effects have generally been considered separately, but may interact in important ways. In particular, a simple model of the melting of the Laurentide ice sheet causes a uniform eustatic sea level rise of 55 m, and also induces a motion of the rotation pole by 0.1 to 1 degree, depending on viscosity structure in the mantle. This motion produces a secular pole tide, which is a spherical harmonic degree 2, order 1 component of the relative sea level pattern, with peak-to-peak amplitude of 20 to 40 m. The maximum effect is along the great circle passing through the path of the pole and at latitudes of ??45??. This secular pole tide has been ignored in most previous attempts to estimate ice sheet loading history and mantle viscosity from global patterns of relative sea level change. It has a large influence along the East coast of North America and the West coast of South America, and significantly contributes to present day rates of relative sea level change.

Impact of sea-level rise on earthquake and landslide triggering offshore the Alentejo margin (SW Iberia)

NASA Astrophysics Data System (ADS)

Neves, M. C.; Roque, C.; Luttrell, K. M.; Vázquez, J. T.; Alonso, B.

2016-12-01

Earthquakes and submarine landslides are recurrent and widespread manifestations of fault activity offshore SW Iberia. The present work tests the effects of sea-level rise on offshore fault systems using Coulomb stress change calculations across the Alentejo margin. Large-scale faults capable of generating large earthquakes and tsunamis in the region, especially NE-SW trending thrusts and WNW-ESE trending dextral strike-slip faults imaged at basement depths, are either blocked or unaffected by flexural effects related to sea-level changes. Large-magnitude earthquakes occurring along these structures may, therefore, be less frequent during periods of sea-level rise. In contrast, sea-level rise promotes shallow fault ruptures within the sedimentary sequence along the continental slope and upper rise within distances of <100 km from the coast. The results suggest that the occurrence of continental slope failures may either increase (if triggered by shallow fault ruptures) or decrease (if triggered by deep fault ruptures) as a result of sea-level rise. Moreover, observations of slope failures affecting the area of the Sines contourite drift highlight the role of sediment properties as preconditioning factors in this region.

The effects of time-varying observation errors on semi-empirical sea-level projections

DOE PAGES

Ruckert, Kelsey L.; Guan, Yawen; Bakker, Alexander M. R.; ...

2016-11-30

Sea-level rise is a key driver of projected flooding risks. The design of strategies to manage these risks often hinges on projections that inform decision-makers about the surrounding uncertainties. Producing semi-empirical sea-level projections is difficult, for example, due to the complexity of the error structure of the observations, such as time-varying (heteroskedastic) observation errors and autocorrelation of the data-model residuals. This raises the question of how neglecting the error structure impacts hindcasts and projections. Here, we quantify this effect on sea-level projections and parameter distributions by using a simple semi-empirical sea-level model. Specifically, we compare three model-fitting methods: a frequentistmore » bootstrap as well as a Bayesian inversion with and without considering heteroskedastic residuals. All methods produce comparable hindcasts, but the parametric distributions and projections differ considerably based on methodological choices. In conclusion, our results show that the differences based on the methodological choices are enhanced in the upper tail projections. For example, the Bayesian inversion accounting for heteroskedasticity increases the sea-level anomaly with a 1% probability of being equaled or exceeded in the year 2050 by about 34% and about 40% in the year 2100 compared to a frequentist bootstrap. These results indicate that neglecting known properties of the observation errors and the data-model residuals can lead to low-biased sea-level projections.« less

Water storage in marine sediment and implications for inferences of past global ice volume

NASA Astrophysics Data System (ADS)

Ferrier, K.; Li, Q.; Pico, T.; Austermann, J.

2017-12-01

Changes in past sea level are of wide interest because they provide information on the sensitivity of ice sheets to climate change, and thus inform predictions of future sea-level change. Sea level changes are influenced by many processes, including the storage of water in sedimentary pore space. Here we use a recent extension of gravitationally self-consistent sea-level models to explore the effects of marine sedimentary water storage on the global seawater balance and inferences of past global ice volume. Our analysis suggests that sedimentary water storage can be a significant component of the global seawater budget over the 105-year timescales associated with glacial-interglacial cycles, and an even larger component over longer timescales. Estimates of global sediment fluxes to the oceans suggest that neglecting marine sedimentary water storage may produce meter-scale errors in estimates of peak global mean sea level equivalent (GMSL) during the Last Interglacial (LIG). These calculations show that marine sedimentary water storage can be a significant contributor to the overall effects of sediment redistribution on sea-level change, and that neglecting sedimentary water storage can lead to substantial errors in inferences of global ice volume at past interglacials. This highlights the importance of accounting for the influences of sediment fluxes and sedimentary water storage on sea-level change over glacial-interglacial timescales.

The effects of time-varying observation errors on semi-empirical sea-level projections

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ruckert, Kelsey L.; Guan, Yawen; Bakker, Alexander M. R.

Sea-level rise is a key driver of projected flooding risks. The design of strategies to manage these risks often hinges on projections that inform decision-makers about the surrounding uncertainties. Producing semi-empirical sea-level projections is difficult, for example, due to the complexity of the error structure of the observations, such as time-varying (heteroskedastic) observation errors and autocorrelation of the data-model residuals. This raises the question of how neglecting the error structure impacts hindcasts and projections. Here, we quantify this effect on sea-level projections and parameter distributions by using a simple semi-empirical sea-level model. Specifically, we compare three model-fitting methods: a frequentistmore » bootstrap as well as a Bayesian inversion with and without considering heteroskedastic residuals. All methods produce comparable hindcasts, but the parametric distributions and projections differ considerably based on methodological choices. In conclusion, our results show that the differences based on the methodological choices are enhanced in the upper tail projections. For example, the Bayesian inversion accounting for heteroskedasticity increases the sea-level anomaly with a 1% probability of being equaled or exceeded in the year 2050 by about 34% and about 40% in the year 2100 compared to a frequentist bootstrap. These results indicate that neglecting known properties of the observation errors and the data-model residuals can lead to low-biased sea-level projections.« less

The role of atmospheric circulation patterns on short-term sea-level fluctuations along the eastern seaboard of the US

NASA Astrophysics Data System (ADS)

Sheridan, S. C.; Lee, C. C.; Pirhalla, D.; Ransi, V.

2017-12-01

Sea-level fluctuations over time are a product of short-term weather events, as well as long-term secular trends in sea-level rise. With sea-levl rise, these fluctuations increasingly have substantial impacts upon coastal ecosystems and impact society through coastal flooding events. In this research, we assess the impact of short-term events, combined with sea-level rise, through synoptic climatological analysis, exploring whether circulation pattern identification can be used to enhance probabilistic forecasts of flood likelihood. Self-organizing maps (SOMs) were created for two discrete atmospheric variables: 700-hPa geopotential height (700z) and sea-level pressure (SLP). For each variable, a SOM array of patterns was created based on data spanning 25°-50°N and 60°-90°W for the period 1979-2014. Sea-level values were derived from tidal gauges between Cape May, New Jersey and Charleston, South Carolina, along the mid-Atlantic coast of the US. Both anomalous sea-level values, as well as nuisance flood occurrence (defined using the local gauge threshold), were assessed. Results show the impacts of both the inverted barometer effect as well as surface wind forcing on sea levels. With SLP, higher sea levels are associated with either patterns that were indicative of on-shore flow or cyclones. At 700z, ridges situated along the east coast are associated with higher sea levels. As the SOM matrix arranges atmospheric patterns in a continuum, the nodes of each SOM show a clear spatial pattern in terms of anomalous sea level, including some significant sea-level anomalies associated with relatively ambiguous pressure patterns. Further, multi-day transitions are also analyzed, showing rapidly deepening cyclones, or persistent onshore flow, can be associated with the greatest likelihood of nuisance floods. Results are weaker with 700z than SLP; however, in some cases, it is clear that the mid-tropospheric circulation can modulate the connection between sea-level anomalies and surface circulation.

Mangrove dieback during fluctuating sea levels.

PubMed

Lovelock, Catherine E; Feller, Ilka C; Reef, Ruth; Hickey, Sharyn; Ball, Marilyn C

2017-05-10

Recent evidence indicates that climate change and intensification of the El Niño Southern Oscillation (ENSO) has increased variation in sea level. Although widespread impacts on intertidal ecosystems are anticipated to arise from the sea level seesaw associated with climate change, none have yet been demonstrated. Intertidal ecosystems, including mangrove forests are among those ecosystems that are highly vulnerable to sea level rise, but they may also be vulnerable to sea level variability and extreme low sea level events. During 16 years of monitoring of a mangrove forest in Mangrove Bay in north Western Australia, we documented two forest dieback events, the most recent one being coincident with the large-scale dieback of mangroves in the Gulf of Carpentaria in northern Australia. Diebacks in Mangrove Bay were coincident with periods of very low sea level, which were associated with increased soil salinization of 20-30% above pre-event levels, leading to canopy loss, reduced Normalized Difference Vegetation Index (NDVI) and reduced recruitment. Our study indicates that an intensification of ENSO will have negative effects on some mangrove forests in parts of the Indo-Pacific that will exacerbate other pressures.

Identifying Decadal to Multi-decadal Variability in the Pacific by Empirical Mode Decomposition

NASA Astrophysics Data System (ADS)

Sommers, L. A.; Hamlington, B.; Cheon, S. H.

2016-12-01

Large scale climate variability in the Pacific Ocean like that associated with ENSO and the Pacific Decadal Oscillation (PDO) has been shown to have a significant impact on climate and sea level across a range of timescales. The changes related to these climate signals have worldwide impacts on fisheries, weather, and precipitation patterns among others. Understanding these inter-annual to multi-decadal oscillations is imperative to longer term climate forecasts and understanding how climate will behave, and its effect on changes in sea level. With a 110-year reconstruction of sea level, we examine decadal to multi-decadal variability seen in the sea level fluctuations in the Pacific Ocean. Using empirical mode decomposition (EMD), we break down regional sea level into a series of intrinsic mode functions (IMFs) and attempt attribution of these IMFs to specific climate modes of variability. In particular, and not unexpectedly, we identify IMFs associated with the PDO, finding correlations between the PDO Index and IMFs in the Pacific Ocean upwards of 0.6-0.8 over the 110-year reconstructed record. Perhaps more significantly, we also find evidence of a longer multi-decadal signal ( 50-60 years) in the higher order IMFs. This lower frequency variability has been suggested in previous literature as influencing GMSL, but here we find a regional pattern associated with this multi-decadal signal. By identifying and separating these periodic climate signals, we can gain a better understanding of how the sea level variability associated with these modes can impact sea level on short timescales and serve to exacerbate the effects of long-term sea level change.

Two Sea-Level Challenges

NASA Astrophysics Data System (ADS)

Galvin, C.

2008-12-01

"No place on the sandy ocean shores of the world has been shown to be eroding because of sea level rise." This statement appeared nearly 19 years ago in bold print at the top of the page in a brief article published in Shore and Beach (Galvin,1990). The term "sea level rise" was defined in 1990 as follows: "In this statement, "sea level rise" has the meaning that the average person on the street usually attaches to that term. That is, sea level is rising; not, as in some places like the Mississippi River delta, land level is sinking." While still a subject of controversy, it is now (2008) increasingly plausible (Tornqvist et al,2008) that damage from Hurricane Katrina was significantly worse on the Mississippi River delta because floodwaters exploited wetlands and levees whose elevations had been lowered by decades of compaction in the underlying soil. (1) "Sea level" commonly appears in the literature as "relative sea level rise", occurring that way in 711 publications between 1980 and 2009 (GeoRef database on 8 Sep 08). "Relative sea level rise" does not appear in the 2005 AGI Glossary. The nearest Glossary term is "relative change in sea level", but that term occurs in only 12 publications between 1980 and 2009. The Glossary defines this term in a sequence stratigraphy sense, which infers that "relative sea level rise" is the sum of bottom subsidence and eustatic sea level rise. In plain English, "relative sea level rise" means "water depth increase". For present day coastal environments, "relative sea level rise" is commonly used where eustatic sea level rise is less than subsidence, that is, where the magnitude of actual sea level rise is smaller than the magnitude of subsidence. In that situation, "relative sea level rise" misleads both the average person and the scientist who is not a coastal geologist. Thus, the first challenge is to abandon "relative sea level rise" in favor of "water depth increase", in order that the words accurately descibe what happens. It would further clarify popular understanding if the term "actual sea level rise" were used in place of "eustatic sea level rise". (2)Geologists have approximated the the practice of paleontologists and biologists in establishing type examples of important geological features. This is a useful practice. A graduate geologist holds in mind clear conceptions of "beach cusps", "drumlin fields", "birdfoot deltas", and "igneous sills" based on seeing field examples accepted by professional geologists as representative of these features. However, although publications frequently report that sea level rise erodes a particular beach, no one identifies a type beach where that cause has been proven to produce the alleged effect. At the type beach, it is necessary to show that sea level is rising, and that the beach erodes primarily from this sea level rise, rather than from interrupted longshore transport. Thus, the second challenge is to identify a type ocean beach proven to erode because of sea level rise.

Coastal Storm Hazards from Virginia to Maine

DTIC Science & Technology

2015-11-01

study, storm surge, tide, waves, wind, atmospheric pressure, and currents were the dominant storm responses computed. The effect of sea level change on...coastal storm hazards and vulnerability nationally (USACE 2015). NACCS goals also included evaluating the effect of future sea level change (SLC) on...the computed high-fidelity responses included storm surge, astronomical tide, waves, wave effects on water levels, storm duration, wind, currents

A modeling study of coastal inundation induced by storm surge, sea-level rise, and subsidence in the Gulf of Mexico

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Zhaoqing; Wang, Taiping; Leung, Lai-Yung R.

The northern coasts of the Gulf of Mexico are highly vulnerable to the direct threats of climate change, such as hurricane-induced storm surge, and such risks can be potentially exacerbated by land subsidence and global sea level rise. This paper presents an application of a coastal storm surge model to study the coastal inundation process induced by tide and storm surge, and its response to the effects of land subsidence and sea level rise in the northern Gulf coast. An unstructured-grid Finite Volume Coastal Ocean Model was used to simulate tides and hurricane-induced storm surges in the Gulf of Mexico.more » Simulated distributions of co-amplitude and co-phase of semi-diurnal and diurnal tides are in good agreement with previous modeling studies. The storm surges induced by four historical hurricanes (Rita, Katrina, Ivan and Dolly) were simulated and compared to observed water levels at National Oceanic and Atmospheric Administration tide stations. Effects of coastal subsidence and future global sea level rise on coastal inundation in the Louisiana coast were evaluated using a parameter “change of inundation depth” through sensitivity simulations that were based on a projected future subsidence scenario and 1-m global sea level rise by the end of the century. Model results suggested that hurricane-induced storm surge height and coastal inundation could be exacerbated by future global sea level rise and subsidence, and that responses of storm surge and coastal inundation to the effects of sea level rise and subsidence are highly nonlinear and vary on temporal and spatial scales.« less

The study of the hydrological regime extreme effects of the Caspian Sea during the XX-XXI centuries

NASA Astrophysics Data System (ADS)

Yaitskaya, Natalia

2016-04-01

The Caspian Sea - the unique largest enclosed inland body of water on Earth. Significant periodic sea level fluctuations are a typical feature of the sea. In the XIX-XX centuries a number of comprehensive studies of the Caspian Sea was carried out. The results are published in the papers, monographs and climatic atlases. But a number of fundamental questions about the features of the hydrological regime of the Caspian Sea is still open: 1. How does the water circulation change during the level variations? 2. What is the effect of heterogeneity of evaporation from the water surface on the formation of the flow field in the conditions of long-term level changes? 3. How does the water salinity regime change depending on the sea level position, water circulation, river flow and different climatic influences? 4. What is the effect of extreme events (multi-hazards) (ice, storms, destruction of the coasts) on coastal infrastructure? In 2016, the project aims to study hydrological regime extreme effects of the Caspian Sea was supported by the Russian Foundation for Basic Research. Within this project all of the above problems will be solved. Geographic information system "Caspian Sea" for the storage and data processing, including a database of primary oceanographic information for the period of instrumental observations (1897-2013), cartographic database (1921-2011) and tools for multidimensional analysis of spatio-temporal information is the basis of the study. The scheme of interconnected hydrodynamic models (Caspian Sea MODel - Ocean Model - Wind wave model) was developed. The important factors are taken into account in the structure of the models: long-term and seasonal dynamics of the sea waves parameters, new long-term values of evaporation from the shallow waters areas of the Caspian Sea, water circulation. Schemes of general seasonal circulation of the Caspian Sea and the Northern Caspian at different positions of the sea level in XX-XXI centuries using interconnected models will be reconstructed. Forecast of seasonal water circulation for the most probable climate change scenarios in the future will be done. Conceptual scheme of calculations of the multi-hazards (ice storms, the destruction of the coasts) in the Caspian Sea was developed. The similar method of calculation was successfully applied to the prediction of natural hazards in the Sea of Azov. The reported study was funded by RFBR, according to the research project No.16-35-60046 mol_a_dk.

Salt marsh as a coastal filter for the oceans: changes in function with experimental increases in nitrogen loading and sea-level rise.

PubMed

Nelson, Joanna L; Zavaleta, Erika S

2012-01-01

Coastal salt marshes are among Earth's most productive ecosystems and provide a number of ecosystem services, including interception of watershed-derived nitrogen (N) before it reaches nearshore oceans. Nitrogen pollution and climate change are two dominant drivers of global-change impacts on ecosystems, yet their interacting effects at the land-sea interface are poorly understood. We addressed how sea-level rise and anthropogenic N additions affect the salt marsh ecosystem process of nitrogen uptake using a field-based, manipulative experiment. We crossed simulated sea-level change and ammonium-nitrate (NH(4)NO(3))-addition treatments in a fully factorial design to examine their potentially interacting effects on emergent marsh plants in a central California estuary. We measured above- and belowground biomass and tissue nutrient concentrations seasonally and found that N-addition had a significant, positive effect on a) aboveground biomass, b) plant tissue N concentrations, c) N stock sequestered in plants, and d) shoot:root ratios in summer. Relative sea-level rise did not significantly affect biomass, with the exception of the most extreme sea-level-rise simulation, in which all plants died by the summer of the second year. Although there was a strong response to N-addition treatments, salt marsh responses varied by season. Our results suggest that in our site at Coyote Marsh, Elkhorn Slough, coastal salt marsh plants serve as a robust N trap and coastal filter; this function is not saturated by high background annual N inputs from upstream agriculture. However, if the marsh is drowned by rising seas, as in our most extreme sea-level rise treatment, marsh plants will no longer provide the ecosystem service of buffering the coastal ocean from eutrophication.

Salt Marsh as a Coastal Filter for the Oceans: Changes in Function with Experimental Increases in Nitrogen Loading and Sea-Level Rise

PubMed Central

Nelson, Joanna L.; Zavaleta, Erika S.

2012-01-01

Coastal salt marshes are among Earth's most productive ecosystems and provide a number of ecosystem services, including interception of watershed-derived nitrogen (N) before it reaches nearshore oceans. Nitrogen pollution and climate change are two dominant drivers of global-change impacts on ecosystems, yet their interacting effects at the land-sea interface are poorly understood. We addressed how sea-level rise and anthropogenic N additions affect the salt marsh ecosystem process of nitrogen uptake using a field-based, manipulative experiment. We crossed simulated sea-level change and ammonium-nitrate (NH4NO3)-addition treatments in a fully factorial design to examine their potentially interacting effects on emergent marsh plants in a central California estuary. We measured above- and belowground biomass and tissue nutrient concentrations seasonally and found that N-addition had a significant, positive effect on a) aboveground biomass, b) plant tissue N concentrations, c) N stock sequestered in plants, and d) shoot:root ratios in summer. Relative sea-level rise did not significantly affect biomass, with the exception of the most extreme sea-level-rise simulation, in which all plants died by the summer of the second year. Although there was a strong response to N-addition treatments, salt marsh responses varied by season. Our results suggest that in our site at Coyote Marsh, Elkhorn Slough, coastal salt marsh plants serve as a robust N trap and coastal filter; this function is not saturated by high background annual N inputs from upstream agriculture. However, if the marsh is drowned by rising seas, as in our most extreme sea-level rise treatment, marsh plants will no longer provide the ecosystem service of buffering the coastal ocean from eutrophication. PMID:22879873

De-confounding of Relations Between Land-Level and Sea-Level Change, Humboldt Bay, Northern California: Uncertain Predictions of Magnitude and Timing of Tectonic and Eustatic Processes

NASA Astrophysics Data System (ADS)

Gilkerson, W.; Leroy, T. H.; Patton, J. R.; Williams, T. B.

2010-12-01

Humboldt Bay in Northern California provides a unique opportunity to investigate the effects of relative sea level change on both native flora and maritime aquiculture as influenced by both tectonic and eustatic sea-level changes. This combination of superposed influences makes quantitatively predicting relative sea-level more uncertain and consumption of the results for public planning purposes exceedingly difficult. Public digestion for practical purposes is confounded by the fact that the uncertainty for eustatic sea-level changes is a magnitude issue while the uncertainty associated with the tectonic land level changes is both a magnitude and timing problem. Secondly, the public is less well informed regarding how crustal deformation contributes to relative sea-level change. We model the superposed effects of eustatic sea-level rise and tectonically driven land-level changes on the spatial distribution of habitats suitable to native eelgrass (Zostera marina) and oyster mariculture operations in Humboldt Bay. While these intertidal organisms were chosen primarily because they have vertically restricted spatial distributions that can be successfully modeled, the public awareness of their ecologic and economic importance is also well developed. We employ easy to understand graphics depicting conceptual ideas along with maps generated from the modeling results to develop locally relevant estimates of future sea level rise over the next 100 years, a time frame consistent with local planning. We bracket these estimates based on the range of possible vertical deformation changes. These graphic displays can be used as a starting point to propose local outcomes from global and regional relative sea-level changes with respect to changes in the distribution of suitable habitat for ecologically and economically valuable species. Currently the largest sources of uncertainty for changes in relative sea-level in the Humboldt Bay area are 1) the rate and magnitude of tectonic deformation throughout the earthquake cycle and 2) the stability and reliability of the tide gauges and other benchmarks assumed to be stable in the Humboldt Bay region.

Sea Level Rise and Climate Change Effects on Marsh Plants Spartina Alterniflora and Typha Angustifolia Using Mesocosms

EPA Science Inventory

A four month experiment using greenhouse mesocosms was conducted to analyze the effect of sea level rise and climate change on salt marsh plants Spartina alterniflora (cordgrass) and Typha angustifolia (narrow-leaved cattail). Our goal was to examine the effects of three differen...

The Potential Effect of Sea Level Rise on Coastal Property Values

NASA Astrophysics Data System (ADS)

O'Donnell, J.

2015-12-01

It is well established that one consequence of increasing global sea level is that the frequency of flooding at low-lying coastal sites will increase. We review recent evidence that the effects coastal geometry will create substantial spatial variations in the changes in flooding frequency with scales of order 100km. Using a simple model of the evolution of coastal property values we demonstrate that a consequence of sea level rise is that the appreciation of coastal properties will peak, and then decline relative to higher properties. The time when the value reach a maximum is shown to depend upon the demand for the coastal property, and the local rate of change of flooding frequency due to sea level rise. The simple model is then extended to include, in an elementary manner, the effects on the value of adjacent but higher properties. We show that the effect of increased flooding frequency of the lower properties leads to an accelerated appreciation of the value of upland properties and an accelerated decline in the value of the coastal properties. We then provide some example calculations for selected sites. We conclude with a discussion of comparisons of the prediction of the analyses to recent data, and then comments on the impact of sea level rise on tax base of coastal communities.

Global mapping of nonseismic sea level oscillations at tsunami timescales.

PubMed

Vilibić, Ivica; Šepić, Jadranka

2017-01-18

Present investigations of sea level extremes are based on hourly data measured at coastal tide gauges. The use of hourly data restricts existing global and regional analyses to periods larger than 2 h. However, a number of processes occur at minute timescales, of which the most ruinous are tsunamis. Meteotsunamis, hazardous nonseismic waves that occur at tsunami timescales over limited regions, may also locally dominate sea level extremes. Here, we show that nonseismic sea level oscillations at tsunami timescales (<2 h) may substantially contribute to global sea level extremes, up to 50% in low-tidal basins. The intensity of these oscillations is zonally correlated with mid-tropospheric winds at the 99% significance level, with the variance doubling from the tropics and subtropics to the mid-latitudes. Specific atmospheric patterns are found during strong events at selected locations in the World Ocean, indicating a globally predominant generation mechanism. Our analysis suggests that these oscillations should be considered in sea level hazard assessment studies. Establishing a strong correlation between nonseismic sea level oscillations at tsunami timescales and atmospheric synoptic patterns would allow for forecasting of nonseismic sea level oscillations for operational use, as well as hindcasting and projection of their effects under past, present and future climates.

Global mapping of nonseismic sea level oscillations at tsunami timescales

PubMed Central

Vilibić, Ivica; Šepić, Jadranka

2017-01-01

Present investigations of sea level extremes are based on hourly data measured at coastal tide gauges. The use of hourly data restricts existing global and regional analyses to periods larger than 2 h. However, a number of processes occur at minute timescales, of which the most ruinous are tsunamis. Meteotsunamis, hazardous nonseismic waves that occur at tsunami timescales over limited regions, may also locally dominate sea level extremes. Here, we show that nonseismic sea level oscillations at tsunami timescales (<2 h) may substantially contribute to global sea level extremes, up to 50% in low-tidal basins. The intensity of these oscillations is zonally correlated with mid-tropospheric winds at the 99% significance level, with the variance doubling from the tropics and subtropics to the mid-latitudes. Specific atmospheric patterns are found during strong events at selected locations in the World Ocean, indicating a globally predominant generation mechanism. Our analysis suggests that these oscillations should be considered in sea level hazard assessment studies. Establishing a strong correlation between nonseismic sea level oscillations at tsunami timescales and atmospheric synoptic patterns would allow for forecasting of nonseismic sea level oscillations for operational use, as well as hindcasting and projection of their effects under past, present and future climates. PMID:28098195

Glacial Isostatic Adjustment and Contemporary Sea Level Rise: An Overview

NASA Astrophysics Data System (ADS)

Spada, Giorgio

2017-01-01

Glacial isostatic adjustment (GIA) encompasses a suite of geophysical phenomena accompanying the waxing and waning of continental-scale ice sheets. These involve the solid Earth, the oceans and the cryosphere both on short (decade to century) and on long (millennia) timescales. In the framework of contemporary sea-level change, the role of GIA is particular. In fact, among the processes significantly contributing to contemporary sea-level change, GIA is the only one for which deformational, gravitational and rotational effects are simultaneously operating, and for which the rheology of the solid Earth is essential. Here, I review the basic elements of the GIA theory, emphasizing the connections with current sea-level changes observed by tide gauges and altimetry. This purpose is met discussing the nature of the "sea-level equation" (SLE), which represents the basis for modeling the sea-level variations of glacial isostatic origin, also giving access to a full set of geodetic variations associated with GIA. Here, the SLE is employed to characterize the remarkable geographical variability of the GIA-induced sea-level variations, which are often expressed in terms of "fingerprints". Using harmonic analysis, the spatial variability of the GIA fingerprints is compared to that of other components of contemporary sea-level change. In closing, some attention is devoted to the importance of the "GIA corrections" in the context of modern sea-level observations, based on tide gauges or satellite altimeters.

Use of a Florida Gulf Coast Barrier Island by Spring Trans-Gulf Migrants and the Projected Effects of Sea Level Rise on Habitat Availability.

PubMed

Lester, Lori A; Gutierrez Ramirez, Mariamar; Kneidel, Alan H; Heckscher, Christopher M

2016-01-01

Barrier islands on the north coast of the Gulf of Mexico are an internationally important coastal resource. Each spring hundreds of thousands of Nearctic-Neotropical songbirds crossing the Gulf of Mexico during spring migration use these islands because they provide the first landfall for individuals following a trans-Gulf migratory route. The effects of climate change, particularly sea level rise, may negatively impact habitat availability for migrants on barrier islands. Our objectives were (1) to confirm the use of St. George Island, Florida by trans-Gulf migrants and (2) to determine whether forested stopover habitat will be available for migrants on St. George Island following sea level rise. We used avian transect data, geographic information systems, remote sensing, and simulation modelling to investigate the potential effects of three different sea level rise scenarios (0.28 m, 0.82 m, and 2 m) on habitat availability for trans-Gulf migrants. We found considerable use of the island by spring trans-Gulf migrants. Migrants were most abundant in areas with low elevation, high canopy height, and high coverage of forests and scrub/shrub. A substantial percentage of forest (44%) will be lost by 2100 assuming moderate sea level rise (0.82 m). Thus, as sea level rise progresses, less forests will be available for migrants during stopover. Many migratory bird species' populations are declining, and degradation of barrier island stopover habitat may further increase the cost of migration for many individuals. To preserve this coastal resource, conservation and wise management of migratory stopover areas, especially near ecological barriers like the Gulf of Mexico, will be essential as sea levels rise.

Use of a Florida Gulf Coast Barrier Island by Spring Trans-Gulf Migrants and the Projected Effects of Sea Level Rise on Habitat Availability

PubMed Central

Lester, Lori A.; Gutierrez Ramirez, Mariamar; Kneidel, Alan H.; Heckscher, Christopher M.

2016-01-01

Barrier islands on the north coast of the Gulf of Mexico are an internationally important coastal resource. Each spring hundreds of thousands of Nearctic-Neotropical songbirds crossing the Gulf of Mexico during spring migration use these islands because they provide the first landfall for individuals following a trans-Gulf migratory route. The effects of climate change, particularly sea level rise, may negatively impact habitat availability for migrants on barrier islands. Our objectives were (1) to confirm the use of St. George Island, Florida by trans-Gulf migrants and (2) to determine whether forested stopover habitat will be available for migrants on St. George Island following sea level rise. We used avian transect data, geographic information systems, remote sensing, and simulation modelling to investigate the potential effects of three different sea level rise scenarios (0.28 m, 0.82 m, and 2 m) on habitat availability for trans-Gulf migrants. We found considerable use of the island by spring trans-Gulf migrants. Migrants were most abundant in areas with low elevation, high canopy height, and high coverage of forests and scrub/shrub. A substantial percentage of forest (44%) will be lost by 2100 assuming moderate sea level rise (0.82 m). Thus, as sea level rise progresses, less forests will be available for migrants during stopover. Many migratory bird species’ populations are declining, and degradation of barrier island stopover habitat may further increase the cost of migration for many individuals. To preserve this coastal resource, conservation and wise management of migratory stopover areas, especially near ecological barriers like the Gulf of Mexico, will be essential as sea levels rise. PMID:26934343

Strain transients in the Gulf of Corinth (Greece)

NASA Astrophysics Data System (ADS)

Canitano, Alexandre; Bernard, Pascal; Linde, Alan; Sacks, Selwyn; Boudin, Frederick

2010-05-01

The Gulf of Corinth (Greece) is one of the most seismic regions in Europe, producing some earthquakes of magnitude greater than 5.8 in the last 35 years, 1 to 1.5 cm/yr of north-south extension, and frequent seismic swarms. This structure is a 110 km long, N110E oriented graben bounded by systems of very recent normal faults. This zone thus provides an ideal site for investigating in situ the physics of earthquake sources and for developing efficient seismic hazard reduction procedures. The Corinth Rift Laboratory (CRL) project is concentrated in the western part of the rift, around the city of Aigion, where instrumental seismicity and strain rate is highest. The CRL Network is made up about fifteen seismic stations as well as tiltmeters, strainmeters or GPS in order to study the local seismicity, and to observe and model the short and long term mechanics of the normal fault system. The instrumental seismicity in the Aigion zone clearly shows a strong concentration of small earthquakes between 5 and 10 km. In order to study slow transient deformation, two borehole strainmeters have been installed in the Gulf (Trizonia, Monasteraki). The strainmeter installed in the Trizonia island is continuously recording the horizontal strain at 150m depth with a resolution better than 10-9. The dominant signal is the earth and sea tidal effects (few 10-7 strain), this one is modulated by the mechanical effects of the free oscillations of the Gulf with periods between 8 and 40 min. The barometric pressure fluctuations acts in combination with the mean sea level variation at longer periods and both effects are not independant. The comparison between the strain data and the two forcing signals (sea-level, barometric pressure) shows clearly a non zero phase delay of the sea-level. The analysis of time correlations between the signals in differents frequency range exhibits that the sea level delay and the strainmeter/sea-level coupling coefficient are increasing with period (about 1/10 of a period for 10-40 hrs period range). This analysis allows us to estimate a transfert function for each forcing signal but the physical interpretation of the sea-level function is difficult. As the strainmeter is at 150m depth, below the shoreline, a sea water percolation on land would increase the effect of sea level fluctuation, and be more efficient at longer periods. This interpretation and the study of the mechanical effects on strainmeter allow us to accurate the sea level admittance and to remove the water effect from the strain data. This residual signals are studied in order to find slow transient signatures, especially during the reported seismic swarms.

Ice2sea - Estimating the future contribution of continental ice to sea-level rise - project summary

NASA Astrophysics Data System (ADS)

Ford, Elaina; Vaughan, David

2013-04-01

Ice2sea brings together the EU's scientific and operational expertise from 24 leading institutions across Europe and beyond. Improved projections of the contribution of ice to sea-level rise produced by this major European-funded programme will inform the fifth IPCC report (due in September 2013). In 2007, the fourth Intergovernmental Panel on Climate Change (IPCC) report highlighted ice-sheets as the most significant remaining uncertainty in projections of sea-level rise. Understanding about the crucial ice-sheet effects was "too limited to assess their likelihood or provide a best estimate of an upper bound for sea-level rise". Ice2sea was created to address these issues - the project started in 2009 and is now drawing to a close, with our final symposium in May 2013, and final publicity activities around the IPCC report release in autumn 2013. Here we present a summary of the overall and key outputs of the ice2sea project.

The land-ice contribution to 21st-century dynamic sea level rise

NASA Astrophysics Data System (ADS)

Howard, T.; Ridley, J.; Pardaens, A. K.; Hurkmans, R. T. W. L.; Payne, A. J.; Giesen, R. H.; Lowe, J. A.; Bamber, J. L.; Edwards, T. L.; Oerlemans, J.

2014-06-01

Climate change has the potential to influence global mean sea level through a number of processes including (but not limited to) thermal expansion of the oceans and enhanced land ice melt. In addition to their contribution to global mean sea level change, these two processes (among others) lead to local departures from the global mean sea level change, through a number of mechanisms including the effect on spatial variations in the change of water density and transport, usually termed dynamic sea level changes. In this study, we focus on the component of dynamic sea level change that might be given by additional freshwater inflow to the ocean under scenarios of 21st-century land-based ice melt. We present regional patterns of dynamic sea level change given by a global-coupled atmosphere-ocean climate model forced by spatially and temporally varying projected ice-melt fluxes from three sources: the Antarctic ice sheet, the Greenland Ice Sheet and small glaciers and ice caps. The largest ice melt flux we consider is equivalent to almost 0.7 m of global mean sea level rise over the 21st century. The temporal evolution of the dynamic sea level changes, in the presence of considerable variations in the ice melt flux, is also analysed. We find that the dynamic sea level change associated with the ice melt is small, with the largest changes occurring in the North Atlantic amounting to 3 cm above the global mean rise. Furthermore, the dynamic sea level change associated with the ice melt is similar regardless of whether the simulated ice fluxes are applied to a simulation with fixed CO2 or under a business-as-usual greenhouse gas warming scenario of increasing CO2.

Army Corps of Engineers: Efforts to Assess the Impact of Extreme Weather Events

DTIC Science & Technology

2015-07-01

evaluate the effects of projected future sea level change on its projects and what to consider when adapting projects to this projected change. In...vulnerability assessments for sea level rise on its coastal projects and has begun conducting such assessments at inland watersheds. U.S. Army Corps of...Army Corps of Engineers’ Hurricane Barrier Design Elevation Changes Due to Sea Level Rise 30 Contents

Effect of high altitude on sensitivity to the taste of phenylthiocarbamide

NASA Astrophysics Data System (ADS)

Singh, S. B.; Chatterjee, A.; Panjwani, U.; Yadav, D. K.; Selvamurthy, W.; Sharma, K. N.

Sensitivity to the taste of phenylthiocarbamide (PTC) was studied using the Harris-Kalmus method in healthy human volunteers at sea level and then subsequently at an altitude of 3500 m over a period of 3 weeks, after which they were brought back to sea level. Blood sugar, insulin and blood cortisol levels were estimated weekly. The results indicated that, out of 51 subjects studied, 26 (55%) were PTC tasters at sea level. Eight of those unable to taste PTC at sea level tested as tasters at high altitude, and 2 of them reverted to being non-tasters on return to sea level. In the blood, an increase in cortisol and blood insulin levels was seen without any significant change in sugar levels. All the changes recorded at high altitude tended to return to basal values after re-induction to sea level. The study suggests that high-altitude hypoxia in some way, possibly involving changes in hormonal profile among other factors, causes an alteration in sensitivity to the taste of PTC, resulting in some of the individuals shifting to lower PTC sensitivity.

Influence of potential sea level rise on societal vulnerability to hurricane storm-surge hazards, Sarasota County, Florida

USGS Publications Warehouse

Frazier, T.G.; Wood, N.; Yarnal, B.; Bauer, D.H.

2010-01-01

Although the potential for hurricanes under current climatic conditions continue to threaten coastal communities, there is concern that climate change, specifically potential increases in sea level, could influence the impacts of future hurricanes. To examine the potential effect of sea level rise on community vulnerability to future hurricanes, we assess variations in socioeconomic exposure in Sarasota County, FL, to contemporary hurricane storm-surge hazards and to storm-surge hazards enhanced by sea level rise scenarios. Analysis indicates that significant portions of the population, economic activity, and critical facilities are in contemporary and future hurricane storm-surge hazard zones. The addition of sea level rise to contemporary storm-surge hazard zones effectively causes population and asset (infrastructure, natural resources, etc) exposure to be equal to or greater than what is in the hazard zone of the next higher contemporary Saffir-Simpson hurricane category. There is variability among communities for this increased exposure, with greater increases in socioeconomic exposure due to the addition of sea level rise to storm-surge hazard zones as one progresses south along the shoreline. Analysis of the 2050 comprehensive land use plan suggests efforts to manage future growth in residential, economic and infrastructure development in Sarasota County may increase societal exposure to hurricane storm-surge hazards. ?? 2010 Elsevier Ltd.

Influence of potential sea level rise on societal vulnerability to hurricane storm-surge hazards, Sarasota County, Florida

USGS Publications Warehouse

Frazier, Tim G.; Wood, Nathan; Yarnal, Brent; Bauer, Denise H.

2010-01-01

Although the potential for hurricanes under current climatic conditions continue to threaten coastal communities, there is concern that climate change, specifically potential increases in sea level, could influence the impacts of future hurricanes. To examine the potential effect of sea level rise on community vulnerability to future hurricanes, we assess variations in socioeconomic exposure in Sarasota County, FL, to contemporary hurricane storm-surge hazards and to storm-surge hazards enhanced by sea level rise scenarios. Analysis indicates that significant portions of the population, economic activity, and critical facilities are in contemporary and future hurricane storm-surge hazard zones. The addition of sea level rise to contemporary storm-surge hazard zones effectively causes population and asset (infrastructure, natural resources, etc) exposure to be equal to or greater than what is in the hazard zone of the next higher contemporary Saffir–Simpson hurricane category. There is variability among communities for this increased exposure, with greater increases in socioeconomic exposure due to the addition of sea level rise to storm-surge hazard zones as one progresses south along the shoreline. Analysis of the 2050 comprehensive land use plan suggests efforts to manage future growth in residential, economic and infrastructure development in Sarasota County may increase societal exposure to hurricane storm-surge hazards.

Measuring the Rate of Change in Sea Level and Its Adherence to USACE Sea Level Rise Planning Scenarios Using Timeseries Metrics

NASA Astrophysics Data System (ADS)

White, K. D.; Huang, N.; Huber, M.; Veatch, W.; Moritz, H.; Obrien, P. S.; Friedman, D.

2017-12-01

In 2013, the United States Army Corps of Engineers (USACE) issued guidance for all Civil Works activities to incorporate the effects of sea level change as described in three distinct planning scenarios.[1] These planning scenarios provided a useful framework to incorporate these effects into Civil Works activities, but required the manual calculation of these scenarios for a given gage and set of datum. To address this need, USACE developed the Sea Level Change Curve Calculator (SLCCC) in 2014 which provided a "simple, web-based tool to provide repeatable analytical results."[2]USACE has been developing a successor to the SLCCC application which retains the same, intuitive functionality to calculate these planning scenarios, but it also allows the comparison of actual sea level change between 1992 and today against the projections, and builds on the user's ability to understand the rate of change using a variety of timeseries metrics (e.g. moving averages, trends) and related visualizations. These new metrics help both illustrate and measure the complexity and nuances of sea level change. [1] ER 1000-2-8162. http://www.publications.usace.army.mil/Portals/76/Publications/EngineerRegulations/ER_1100-2-8162.pdf. [2] SLCC Manual. http://www.corpsclimate.us/docs/SLC_Calculator_Manual_2014_88.pdf.

Impact of sea level rise on tide gate function.

PubMed

Walsh, Sean; Miskewitz, Robert

2013-01-01

Sea level rise resulting from climate change and land subsidence is expected to severely impact the duration and associated damage resulting from flooding events in tidal communities. These communities must continuously invest resources for the maintenance of existing structures and installation of new flood prevention infrastructure. Tide gates are a common flood prevention structure for low-lying communities in the tidal zone. Tide gates close during incoming tides to prevent inundation from downstream water propagating inland and open during outgoing tides to drain upland areas. Higher downstream mean sea level elevations reduce the effectiveness of tide gates by impacting the hydraulics of the system. This project developed a HEC-RAS and HEC-HMS model of an existing tide gate structure and its upland drainage area in the New Jersey Meadowlands to simulate the impact of rising mean sea level elevations on the tide gate's ability to prevent upstream flooding. Model predictions indicate that sea level rise will reduce the tide gate effectiveness resulting in longer lasting and deeper flood events. The results indicate that there is a critical point in the sea level elevation for this local area, beyond which flooding scenarios become dramatically worse and would have a significantly negative impact on the standard of living and ability to do business in one of the most densely populated areas of America.

Effect of different implementations of the same ice history in GIA modeling

NASA Astrophysics Data System (ADS)

Barletta, V. R.; Bordoni, A.

2013-11-01

This study shows the effect of changing the way ice histories are implemented in Glacial Isostatic Adjustment (GIA) codes to solve the sea level equation. The ice history models are being constantly improved and are provided in different formats. The overall algorithmic design of the sea-level equation solver often forces to implement the ice model in a representation that differs from the one originally provided. We show that using different representations of the same ice model gives important differences and artificial contributions to the sea level estimates, both at global and at regional scale. This study is not a speculative exercise. The ICE-5G model adopted in this work is widely used in present day sea-level analysis, but discrepancies between the results obtained by different groups for the same ice models still exist, and it was the effort to set a common reference for the sea-level community that inspired this work. Understanding this issue is important to be able to reduce the artefacts introduced by a non-suitable ice model representation. This is especially important when developing new GIA models, since neglecting this problem can easily lead to wrong alignment of the ice and sea-level histories, particularly close to the deglaciation areas, like Antarctica.

Under-estimated wave contribution to coastal sea-level rise

NASA Astrophysics Data System (ADS)

Melet, Angélique; Meyssignac, Benoit; Almar, Rafael; Le Cozannet, Gonéri

2018-03-01

Coastal communities are threatened by sea-level changes operating at various spatial scales; global to regional variations are associated with glacier and ice sheet loss and ocean thermal expansion, while smaller coastal-scale variations are also related to atmospheric surges, tides and waves. Here, using 23 years (1993-2015) of global coastal sea-level observations, we examine the contribution of these latter processes to long-term sea-level rise, which, to date, have been relatively less explored. It is found that wave contributions can strongly dampen or enhance the effects of thermal expansion and land ice loss on coastal water-level changes at interannual-to-multidecadal timescales. Along the US West Coast, for example, negative wave-induced trends dominate, leading to negative net water-level trends. Accurate estimates of past, present and future coastal sea-level rise therefore need to consider low-frequency contributions of wave set-up and swash.

Climate change impacts on tropical cyclones and extreme sea levels in the South Pacific — A regional assessment

NASA Astrophysics Data System (ADS)

Walsh, Kevin J. E.; McInnes, Kathleen L.; McBride, John L.

2012-01-01

This paper reviews the current understanding of the effect of climate change on extreme sea levels in the South Pacific region. This region contains many locations that are vulnerable to extreme sea levels in the current climate, and projections indicate that this vulnerability will increase in the future. The recent publication of authoritative statements on the relationship between global warming and global sea level rise, tropical cyclones and the El Niño-Southern Oscillation phenomenon has motivated this review. Confident predictions of global mean sea level rise are modified by regional differences in the steric (density-related) component of sea level rise and changing gravitational interactions between the ocean and the ice sheets which affect the regional distribution of the eustatic (mass-related) contribution to sea level rise. The most extreme sea levels in this region are generated by tropical cyclones. The intensity of the strongest tropical cyclones is likely to increase, but many climate models project a substantial decrease in tropical cyclone numbers in this region, which may lead to an overall decrease in the total number of intense tropical cyclones. This projection, however, needs to be better quantified using improved high-resolution climate model simulations of tropical cyclones. Future changes in ENSO may lead to large regional variations in tropical cyclone incidence and sea level rise, but these impacts are also not well constrained. While storm surges from tropical cyclones give the largest sea level extremes in the parts of this region where they occur, other more frequent high sea level events can arise from swell generated by distant storms. Changes in wave climate are projected for the tropical Pacific due to anthropogenically-forced changes in atmospheric circulation. Future changes in sea level extremes will be caused by a combination of changes in mean sea level, regional sea level trends, tropical cyclone incidence and wave climate. Recommendations are given for research to increase understanding of the response of these factors to climate change. Implications of the results for adaptation research are also discussed.

Sea level and turbidity controls on mangrove soil surface elevation change

USGS Publications Warehouse

Lovelock, Catherine E.; Fernanda Adame, Maria; Bennion, Vicki; Hayes, Matthew; Reef, Ruth; Santini, Nadia; Cahoon, Donald R.

2015-01-01

Increases in sea level are a threat to seaward fringing mangrove forests if levels of inundation exceed the physiological tolerance of the trees; however, tidal wetlands can keep pace with sea level rise if soil surface elevations can increase at the same pace as sea level rise. Sediment accretion on the soil surface and belowground production of roots are proposed to increase with increasing sea level, enabling intertidal habitats to maintain their position relative to mean sea level, but there are few tests of these predictions in mangrove forests. Here we used variation in sea level and the availability of sediments caused by seasonal and inter-annual variation in the intensity of La Nina-El Nino to assess the effects of increasing sea level on surface elevation gains and contributing processes (accretion on the surface, subsidence and root growth) in mangrove forests. We found that soil surface elevation increased with mean sea level (which varied over 250 mm during the study) and with turbidity at sites where fine sediment in the water column is abundant. In contrast, where sediments were sandy, rates of surface elevation gain were high, but not significantly related to variation in turbidity, and were likely to be influenced by other factors that deliver sand to the mangrove forest. Root growth was not linked to soil surface elevation gains, although it was associated with reduced shallow subsidence, and therefore may contribute to the capacity of mangroves to keep pace with sea level rise. Our results indicate both surface (sedimentation) and subsurface (root growth) processes can influence mangrove capacity to keep pace with sea level rise within the same geographic location, and that current models of tidal marsh responses to sea level rise capture the major feature of the response of mangroves where fine, but not coarse, sediments are abundant.

Extreme Sea Level Rise Event Linked to 2009-10 AMOC Downturn

NASA Astrophysics Data System (ADS)

Yin, J.

2016-02-01

The coastal sea levels along the Northeast Coast of North America show significant year-to-year fluctuations in a general upward trend. Our analysis of long-term tide gauge records along the North American east coast identified an extreme sea-level rise (SLR) event during 2009-2010. Within this relatively brief two-year period, coastal sea levels north of New York City jumped by 100 mm. This magnitude of inter-annual SLR is unprecedented in the century-long tide gauge records, with statistical methods suggesting that it was a 1-in-850 year event. We show that this extreme SLR event was a combined effect of two physical factors. First, it was partly due to an observed 30% downturn of the Atlantic meridional overturning circulation (AMOC) during 2009-2010. This AMOC slowdown caused a significant decline of the dynamic sea level gradient across the Gulf Stream and North Atlantic Current, thereby imparting a rise in coastal sea level. The second contributing factor to the extreme SLR event was due to a significant negative North Atlantic Oscillation (NAO) index. The associated easterly or northeasterly wind anomalies acted to push ocean waters towards the Northeast Coast through the Ekman transport, resulting in further rise in coastal sea levels. Sea level pressure anomalies also contributed to the extreme SLR event through the inverse barometer effect. To project future extreme sea levels along the east coast of North America during the 21st century, we make use of a suite of climate/Earth system models developed at GFDL and other modeling centers. These models included typical CMIP5-class models, as well as the newer climate models GFDL CM2.5 and CM2.6 with eddying oceans. In response to the increase in greenhouse-gas concentrations, each of these models show a reduction in the AMOC. Given the observed connection between AMOC reduction and extreme coastal sea levels, the models thus project an increase in extreme SLR frequency on interannual time scales along the Northeast Coast of North America.

Sea-level responses to sediment transport over the last ice age cycle

NASA Astrophysics Data System (ADS)

Ferrier, K.; Mitrovica, J. X.

2013-12-01

Sea-level changes over the last ice age cycle were instrumental in steering Earth's topographic evolution. These sea-level variations were driven by changes in surface mass loads, including not only ice and ocean mass variations but also the transfer of rock from eroding mountains to sedimentary deposits. Here we use an extended numerical model of ice age sea level (Dalca et al., 2013) to explore how sediment erosion and deposition affected global sea-level variations over the last ice age cycle. The model takes histories of ice and sediment loads as inputs, and it computes gravitationally self-consistent sea level responses by accounting for the deformational, gravitational, and rotational perturbations in the Earth's viscoelastic form. In these model simulations, we use published estimates of erosion rates, sedimentation rates, and ice sheet variations to constrain sediment and ice loading since the Last Interglacial. We explore sea-level responses to several erosional and depositional scenarios, and in each we quantify the relative contributions of crustal deformation and gravitational perturbation to the computed sea-level change. We also present a case study to illustrate the effects that sediment transfer can have on sea level at the regional scale. In particular, we focus on the region surrounding the Indus River, where fluvial sediment fluxes are among the highest on Earth. Preliminary model results suggest that sediment fluxes from Asia to the ocean are large enough to produce a significant response in sea level along the northeastern coast of the Arabian Sea. Moreover, they suggest that modeled sea-level histories are sensitive to the timing and spatial distribution of sediment erosion and deposition. For instance, sediment deposition along the continental shelf - which may have been the primary site of Indus River sediment deposition during the Holocene - produces a different sea-level response than sediment deposition on the deep-sea Indus Fan, where most of the Indus sediment may have been deposited during the glacial period preceding the Holocene. These simulations highlight the role that massive continent-to-ocean sediment fluxes can play in driving sea-level patterns over thousands of years. References: Dalca A.V., Ferrier K.L., Mitrovica J.X., Perron J.T., Milne G.A., Creveling J.R., 2013. On postglacial sea level - III: Incorporating sediment redistribution. Geophys. J. Int., doi: 10.1093/gji/ggt089.

Ice2sea - the future glacial contribution to sea-level rise

NASA Astrophysics Data System (ADS)

Vaughan, D. G.; Ice2sea Consortium

2009-04-01

The melting of continental ice (glaciers, ice caps and ice sheets) is a substantial source of current sea-level rise, and one that is accelerating more rapidly than was predicted even a few years ago. Indeed, the most recent report from Intergovernmental Panel on Climate Change highlighted that the uncertainty in projections of future sea-level rise is dominated by uncertainty concerning continental ice, and that understanding of the key processes that will lead to loss of continental ice must be improved before reliable projections of sea-level rise can be produced. Such projections are urgently required for effective sea-defence management and coastal adaptation planning. Ice2sea is a consortium of European institutes and international partners seeking European funding to support an integrated scientific programme to improve understanding concerning the future glacial contribution to sea-level rise. This includes improving understanding of the processes that control, past, current and future sea-level rise, and generation of improved estimates of the contribution of glacial components to sea-level rise over the next 200 years. The programme will include targeted studies of key processes in mountain glacier systems and ice caps (e.g. Svalbard), and in ice sheets in both polar regions (Greenland and Antarctica) to improve understanding of how these systems will respond to future climate change. It will include fieldwork and remote sensing studies, and develop a suite of new, cross-validated glacier and ice-sheet model. Ice2sea will deliver these results in forms accessible to scientists, policy-makers and the general public, which will include clear presentations of the sources of uncertainty. Our aim is both, to provide improved projections of the glacial contribution to sea-level rise, and to leave a legacy of improved tools and techniques that will form the basis of ongoing refinements in sea-level projection. Ice2sea will provide exciting opportunities for many early-career glaciologists and ice-modellers in a variety of host institutes.

Coastal Impact Underestimated From Rapid Sea Level Rise

NASA Astrophysics Data System (ADS)

Anderson, John; Milliken, Kristy; Wallace, Davin; Rodriguez, Antonio; Simms, Alexander

2010-06-01

A primary effect of global warming is accelerated sea level rise, which will eventually drown low-lying coastal areas, including some of the world's most populated cities. Predictions from the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) suggest that sea level may rise by as much as 0.6 meter by 2100 [Solomon et al., 2007]. However, uncertainty remains about how projected melting of the Greenland and Antarctic ice sheets will contribute to sea level rise. Further, considerable variability is introduced to these calculations due to coastal subsidence, especially along the northern Gulf of Mexico (see http://tidesandcurrents.noaa.gov/sltrends/sltrends.shtml).

Contribution of atmospheric circulation to recent off-shore sea-level variations in the Baltic Sea and the North Sea

NASA Astrophysics Data System (ADS)

Karabil, Sitar; Zorita, Eduardo; Hünicke, Birgit

2018-01-01

The main purpose of this study is to quantify the contribution of atmospheric factors to recent off-shore sea-level variability in the Baltic Sea and the North Sea on interannual timescales. For this purpose, we statistically analysed sea-level records from tide gauges and satellite altimetry and several climatic data sets covering the last century. Previous studies had concluded that the North Atlantic Oscillation (NAO) is the main pattern of atmospheric variability affecting sea level in the Baltic Sea and the North Sea in wintertime. However, we identify a different atmospheric circulation pattern that is more closely connected to sea-level variability than the NAO. This circulation pattern displays a link to sea level that remains stable through the 20th century, in contrast to the much more variable link between sea level and the NAO. We denote this atmospheric variability mode as the Baltic Sea and North Sea Oscillation (BANOS) index. The sea-level pressure (SLP) BANOS pattern displays an SLP dipole with centres of action located over (5° W, 45° N) and (20° E, 70° N) and this is distinct from the standard NAO SLP pattern in wintertime. In summertime, the discrepancy between the SLP BANOS and NAO patterns becomes clearer, with centres of action of the former located over (30° E, 45° N) and (20° E, 60° N). This index has a stronger connection to off-shore sea-level variability in the study area than the NAO in wintertime for the period 1993-2013, explaining locally up to 90 % of the interannual sea-level variance in winter and up to 79 % in summer. The eastern part of the Gulf of Finland is the area where the BANOS index is most sensitive to sea level in wintertime, whereas the Gulf of Riga is the most sensitive region in summertime. In the North Sea region, the maximum sea-level sensitivity to the BANOS pattern is located in the German Bight for both winter and summer seasons. We investigated, and when possible quantified, the contribution of several physical mechanisms which may explain the link between the sea-level variability and the atmospheric pattern described by the BANOS index. These mechanisms include the inverse barometer effect (IBE), freshwater balance, net energy surface flux and wind-induced water transport. We found that the most important mechanism is the IBE in both wintertime and summertime. Assuming a complete equilibration of seasonal sea level to the SLP gradients over this region, the IBE can explain up to 88 % of the sea-level variability attributed to the BANOS index in wintertime and 34 % in summertime. The net energy flux at the surface is found to be an important factor for the variation of sea level, explaining 35 % of sea-level variance in wintertime and a very small amount in summer. The freshwater flux could only explain 27 % of the variability in summertime and a negligible part in winter. In contrast to the NAO, the direct wind forcing associated with the SLP BANOS pattern does not lead to transport of water from the North Sea into the Baltic Sea in wintertime.

Precise mean sea level measurements using the Global Positioning System

NASA Technical Reports Server (NTRS)

Kelecy, Thomas M.; Born, George H.; Parke, Michael E.; Rocken, Christian

1994-01-01

This paper describes the results of a sea level measurement test conducted off La Jolla, California, in November of 1991. The purpose of this test was to determine accurate sea level measurements using a Global Positioning System (GPS) equipped buoy. These measurements were intended to be used as the sea level component for calibration of the ERS 1 satellite altimeter. Measurements were collected on November 25 and 28 when the ERS 1 satellite overflew the calibration area. Two different types of buoys were used. A waverider design was used on November 25 and a spar design on November 28. This provided the opportunity to examine how dynamic effects of the measurement platform might affect the sea level accuracy. The two buoys were deployed at locations approximately 1.2 km apart and about 15 km west of a reference GPS receiver located on the rooftop of the Institute of Geophysics and Planetary Physics at the Scripps Institute of Oceanography. GPS solutions were computed for 45 minutes on each day and used to produce two sea level time series. An estimate of the mean sea level at both locations was computed by subtracting tide gage data collected at the Scripps Pier from the GPS-determined sea level measurements and then filtering out the high-frequency components due to waves and buoy dynamics. In both cases the GPS estimate differed from Rapp's mean altimetric surface by 0.06 m. Thus, the gradient in the GPS measurements matched the gradient in Rapp's surface. These results suggest that accurate sea level can be determined using GPS on widely differing platforms as long as care is taken to determine the height of the GPS antenna phase center above water level. Application areas include measurement of absolute sea level, of temporal variations in sea level, and of sea level gradients (dominantly the geoid). Specific applications would include ocean altimeter calibration, monitoring of sea level in remote regions, and regional experiments requiring spatial and temporal resolution higher than that available from altimeter data.

Deep Sea Frontiers: Aid In Preparing a Book MS for Publication

DTIC Science & Technology

2001-09-30

about 200 m, are increasingly low levels of sunlight absorbed and scattered by the water column. As a result little or no photosynthetic...fish carcasses that reach the bottom from upper levels of the sea. To find this random, but crucial, manna, they must actively and effectively search...sea level , the thermodynamic p delta V element of the reaction kinetics is ignored because its contribution is nearly zero. But if metabolic

Model projections of rapid sea-level rise on the northeast coast of the United States

NASA Astrophysics Data System (ADS)

Yin, Jianjun; Schlesinger, Michael E.; Stouffer, Ronald J.

2009-04-01

Human-induced climate change could cause global sea-level rise. Through the dynamic adjustment of the sea surface in response to a possible slowdown of the Atlantic meridional overturning circulation, a warming climate could also affect regional sea levels, especially in the North Atlantic region, leading to high vulnerability for low-lying Florida and western Europe. Here we analyse climate projections from a set of state-of-the-art climate models for such regional changes, and find a rapid dynamical rise in sea level on the northeast coast of the United States during the twenty-first century. For New York City, the rise due to ocean circulation changes amounts to 15, 20 and 21cm for scenarios with low, medium and high rates of emissions respectively, at a similar magnitude to expected global thermal expansion. Analysing one of the climate models in detail, we find that a dynamic, regional rise in sea level is induced by a weakening meridional overturning circulation in the Atlantic Ocean, and superimposed on the global mean sea-level rise. We conclude that together, future changes in sea level and ocean circulation will have a greater effect on the heavily populated northeastern United States than estimated previously.

Model Projections of Rapid Sea-Level Rise on the Northeast Coast of the United States

NASA Astrophysics Data System (ADS)

Yin, J.; Schlesinger, M.; Stouffer, R. J.

2009-12-01

Human-induced climate change could cause global sea-level rise. Through the dynamic adjustment of the sea surface in response to a possible slowdown of the Atlantic meridional overturning circulation, a warming climate could also affect regional sea levels, especially in the North Atlantic region, leading to high vulnerability for low-lying Florida and western Europe. In the present study, we analyse climate projections from a set of state-of-the-art climate models for such regional changes, and find a rapid dynamical rise in sea level on the northeast coast of the United States during the twenty-first century. For New York City, the rise due to ocean circulation changes amounts to 15, 20 and 21 cm for scenarios with low, medium and high rates of emissions respectively, at a similar magnitude to expected global thermal expansion. Analysing one of the climate models in detail, we find that a dynamic, regional rise in sea level is induced by a weakening meridional overturning circulation in the Atlantic Ocean, and superimposed on the global mean sea level rise. We conclude that together, future changes in sea level and ocean circulation will have a greater effect on the heavily populated northeastern United States than estimated previously.

Modeling and Analysis of Sea-level Rise Impacts on Salinity in the Lower St. Johns River

NASA Astrophysics Data System (ADS)

Bacopoulos, P.

2015-12-01

There is deliberate attention being paid to studying sea-level rise impacts on the lower St. Johns River, a drowned coastal plain-type estuary with low topographic drive, located in northeastern Florida. One area of attention is salinity in the river, which influences the entire food web, including sea and marsh grasses, juvenile crustaceans and fishes, wading birds and migratory waterfowl, marine mammals and other predator animals. It is expected that elevated ocean levels will increase the salinity of the estuarine waters, leading to deleterious effects on dependent species of the river biology. The objective of the modeling and analysis was: 1) to establish baseline conditions of salinity for the lower St. Johns River; and 2) to examine future conditions of salinity, as impacted by sea-level rise. Establishing baseline conditions entailed validation of the model for present-day salinity in the lower St. Johns River via comparison to available data. Examining future conditions entailed application of the model for sea-level rise scenarios, with comparison to the baseline conditions, for evaluation of sea-level rise impacts on salinity. While the central focus was on the physics of sea-level rise impacts on salinity, some level of salinity-biological assessment was conducted to identify sea-level rise/salinity thresholds, as related to negatively impacting different species of the river biology.

Incorporating Infrastructure and Vegetation Effects on Sea Level Rise Predictions in Low-Gradient Coastal Landscapes

NASA Astrophysics Data System (ADS)

Rodriguez, J. F.; Sandi Rojas, S.; Trivisonno, F.; Saco, P. M.; Riccardi, G.

2015-12-01

At the regional and global scales, coastal management and planning for future sea level rise scenarios is typically supported by modelling tools that predict the expected inundation extent. These tools rely on a number of simplifying assumptions that, in some cases, may result in important overestimation or underestimation of the inundation extent. One of such cases is coastal wetlands, where vegetation strongly affects both the magnitude and the timing of inundation. Many coastal wetlands display other forms of flow restrictions due to, for example, infrastructure or drainage works, which also alters the inundation patterns. In this contribution we explore the effects of flow restrictions on inundation patterns under sea level rise conditions in coastal wetlands. We use a dynamic wetland evolution model that not only incorporates the effects of flow restrictions due to culverts, bridges and weirs as well as vegetation, but also considers that vegetation changes as a consequence of increasing inundation. We apply our model to a coastal wetland in Australia and compare predictions of our model to predictions using conventional approaches. We found that some restrictions accentuate detrimental effects of sea level rise while others moderate them. We also found that some management strategies based on flow redistribution that provide short term solution may result more damaging in the long term if sea level rise is considered.

Sea level variations during rapid changing Arctic Ocean from tide gauge and satellite altimetry

NASA Astrophysics Data System (ADS)

Du, Ling; Xu, Daohuan

2016-04-01

Sea level variations can introduce the useful information under the circumstance of the rapid changing Arctic. Based on tide gauge records and the satellite altimetry data in the Arctic Ocean, the sea level variations in the 20th century are analyzed with the stochastic dynamic method. The average secular trend of the sea level record is about 1 mm/yr, which is smaller than the global mean cited by the IPCC climate assessment report. The secular trend in the coastal region differs from that in the deep water. After the mid-1970s, a weak acceleration of sea level rise is found along the coasts of the Siberian and Aleutian Islands. Analysis of synchronous TOPEX/Poseidon altimetry data indicates that the amplitude of the seasonal variation is less than that of the inter-annual variation, whose periods vary from 4.7 to 6 years. This relationship is different from that in the mid-latitudes. The climate indices are the pre-cursors of the sea level variations on multi-temporal scales. The model results show that while steric effects contribute significantly to the seasonal variation, the influence of atmospheric wind forcing is an important factor of sea level during ice free region.

Relative sea-level rise as indicated by gage data along the Mississippi and Alabama Gulf Coasts

USGS Publications Warehouse

Van Wilson, K.

2004-01-01

Global warming, or the increasing of earth's temperatures, leads to rising sea level as polar ice caps and mountain glaciers melt and ocean water undergoes thermal expansion. Tidal records collected by the U.S. Army Corps of Engineers (COE), Mobile District, at Gulfport, Biloxi, and Pascagoula, Mississippi, and at Mobile, Alabama, indicate trends of water-surface elevations increasing with time (relative sea-level rise). The trends indicated by the COE data were compared to relative sea-level trends indicated by the National Ocean Survey gages in the Gulf of Mexico. The average global rate of sea level rise has been suggested to approach about 2 mm/yr (0.007 ft/yr). Some leading scientists have suggested rates of sea level rise that are greater than 2 mm/yr, when accounting for effects of greenhouse gas emissions. As the sea level rises and inundates the coastal plain, structures along the existing coast and structures located in the back bays of estuaries will be even more adversely affected by future flooding. Also, if the land surface adjacent to the water also sinks due to soil compaction and other geologic processes (collectively call subsidence), additional land will be inundated. Copyright ASCE 2004.

Intensification of decadal and multi-decadal sea level variability in the western tropical Pacific during recent decades

NASA Astrophysics Data System (ADS)

Han, Weiqing; Meehl, Gerald A.; Hu, Aixue; Alexander, Michael A.; Yamagata, Toshio; Yuan, Dongliang; Ishii, Masayoshi; Pegion, Philip; Zheng, Jian; Hamlington, Benjamin D.; Quan, Xiao-Wei; Leben, Robert R.

2014-09-01

Previous studies have linked the rapid sea level rise (SLR) in the western tropical Pacific (WTP) since the early 1990s to the Pacific decadal climate modes, notably the Pacific Decadal Oscillation in the north Pacific or Interdecadal Pacific Oscillation (IPO) considering its basin wide signature. Here, the authors investigate the changing patterns of decadal (10-20 years) and multidecadal (>20 years) sea level variability (global mean SLR removed) in the Pacific associated with the IPO, by analyzing satellite and in situ observations, together with reconstructed and reanalysis products, and performing ocean and atmosphere model experiments. Robust intensification is detected for both decadal and multidecadal sea level variability in the WTP since the early 1990s. The IPO intensity, however, did not increase and thus cannot explain the faster SLR. The observed, accelerated WTP SLR results from the combined effects of Indian Ocean and WTP warming and central-eastern tropical Pacific cooling associated with the IPO cold transition. The warm Indian Ocean acts in concert with the warm WTP and cold central-eastern tropical Pacific to drive intensified easterlies and negative Ekman pumping velocity in western-central tropical Pacific, thereby enhancing the western tropical Pacific SLR. On decadal timescales, the intensified sea level variability since the late 1980s or early 1990s results from the "out of phase" relationship of sea surface temperature anomalies between the Indian and central-eastern tropical Pacific since 1985, which produces "in phase" effects on the WTP sea level variability.

Estimation of sea level variations with GPS/GLONASS-reflectometry technique

NASA Astrophysics Data System (ADS)

Padokhin, A. M.; Kurbatov, G. A.; Andreeva, E. S.; Nesterov, I. A.; Nazarenko, M. O.; Berbeneva, N. A.; Karlysheva, A. V.

2017-11-01

In the present paper we study GNSS - reflectometry methods for estimation of sea level variations using a single GNSSreceiver, which are based on the multipath propagation effects caused by the reflection of navigational signals from the sea surface. Such multipath propagation results in the appearance of the interference pattern in the Signal-to-Noise Ratio (SNR) of GNSS signals at small satellite elevation angles, which parameters are determined by the wavelength of the navigational signal and height of the antenna phase center above the reflecting sea surface. In current work we used GPS and GLONASS signals and measurements at two working frequencies of both systems to study sea level variations which almost doubles the amount of observations compared to GPS-only tide gauge. For UNAVCO sc02 station and collocated Friday Harbor NOAA tide gauge we show good agreement between GNSS-reflectometry and traditional mareograph sea level data.

Soccer activity profile of altitude versus sea-level natives during acclimatisation to 3600 m (ISA3600)

PubMed Central

Aughey, Robert J; Hammond, Kristal; Varley, Matthew C; Schmidt, Walter F; Bourdon, Pitre C; Buchheit, Martin; Simpson, Ben; Garvican-Lewis, Laura A; Kley, Marlen; Soria, Rudy; Sargent, Charli; Roach, Gregory D; Claros, Jesus C Jimenez; Wachsmuth, Nadine; Gore, Christopher J

2013-01-01

Objectives We investigated the effect of high altitude on the match activity profile of elite youth high altitude and sea level residents. Methods Twenty Sea Level (Australian) and 19 Altitude-resident (Bolivian) soccer players played five games, two near sea level (430 m) and three in La Paz (3600 m). Match activity profile was quantified via global positioning system with the peak 5 min period for distance ((D5peak)) and high velocity running (>4.17 m/s, HIVR5peak); as well as the 5 min period immediately subsequent to the peak for both distance (D5sub) and high-velocity running (HIVR5sub) identified using a rolling 5 min epoch. The games at 3600 m were compared with the average of the two near sea-level games. Results The total distance per minute was reduced by a small magnitude in the first match at altitude in both teams, without any change in low-velocity running. There were variable changes in HiVR, D5peak and HiVR5peak from match to match for each team. There were within-team reductions in D5peak in each game at altitude compared with those at near sea level, and this reduction was greater by a small magnitude in Australians than Bolivians in game 4. The effect of altitude on HiVR5peak was moderately lower in Australians compared with Bolivians in game 3. There was no clear difference in the effect of altitude on maximal accelerations between teams. Conclusions High altitude reduces the distance covered by elite youth soccer players during matches. Neither 13 days of acclimatisation nor lifelong residence at high altitude protects against detrimental effects of altitude on match activity profile. PMID:24282196

Soccer activity profile of altitude versus sea-level natives during acclimatisation to 3600 m (ISA3600).

PubMed

Aughey, Robert J; Hammond, Kristal; Varley, Matthew C; Schmidt, Walter F; Bourdon, Pitre C; Buchheit, Martin; Simpson, Ben; Garvican-Lewis, Laura A; Kley, Marlen; Soria, Rudy; Sargent, Charli; Roach, Gregory D; Claros, Jesus C Jimenez; Wachsmuth, Nadine; Gore, Christopher J

2013-12-01

We investigated the effect of high altitude on the match activity profile of elite youth high altitude and sea level residents. Twenty Sea Level (Australian) and 19 Altitude-resident (Bolivian) soccer players played five games, two near sea level (430 m) and three in La Paz (3600 m). Match activity profile was quantified via global positioning system with the peak 5 min period for distance ((D₅(peak)) and high velocity running (>4.17 m/s, HIVR₅(peak)); as well as the 5 min period immediately subsequent to the peak for both distance (D₅(sub)) and high-velocity running (HIVR₅(sub)) identified using a rolling 5 min epoch. The games at 3600 m were compared with the average of the two near sea-level games. The total distance per minute was reduced by a small magnitude in the first match at altitude in both teams, without any change in low-velocity running. There were variable changes in HiVR, D₅(peak) and HiVR₅(peak) from match to match for each team. There were within-team reductions in D₅(peak) in each game at altitude compared with those at near sea level, and this reduction was greater by a small magnitude in Australians than Bolivians in game 4. The effect of altitude on HiVR₅(peak) was moderately lower in Australians compared with Bolivians in game 3. There was no clear difference in the effect of altitude on maximal accelerations between teams. High altitude reduces the distance covered by elite youth soccer players during matches. Neither 13 days of acclimatisation nor lifelong residence at high altitude protects against detrimental effects of altitude on match activity profile.

Concerns--High Sea Levels and Temperatures Seen Next Century.

ERIC Educational Resources Information Center

Ryan, Paul R.

1984-01-01

A National Research Council committee recently concluded that atmospheric carbon dioxide levels will "most likely" double by late in the next century, causing an increase in the earth's average temperature. Effects of the increase on sea levels, global climate, and other parameters are discussed. (JN)

Direct and indirect controls on organic matter decomposition in four coastal wetland communities along a landscape salinity gradient

USGS Publications Warehouse

Stagg, Camille L.; Baustian, Melissa M.; Perry, Carey L.; Carruthers, Tim J.B.; Hall, Courtney T.

2018-01-01

Coastal wetlands store more carbon than most ecosystems globally. As sea level rises, changes in flooding and salinity will potentially impact ecological functions, such as organic matter decomposition, that influence carbon storage. However, little is known about the mechanisms that control organic matter loss in coastal wetlands at the landscape scale. As sea level rises, how will the shift from fresh to salt-tolerant plant communities impact organic matter decomposition? Do long-term, plant-mediated, effects of sea-level rise differ from direct effects of elevated salinity and flooding?We identified internal and external factors that regulated indirect and direct pathways of sea-level rise impacts, respectively, along a landscape-scale salinity gradient that incorporated changes in wetland type (fresh, oligohaline, mesohaline and polyhaline marshes). We found that indirect and direct impacts of sea-level rise had opposing effects on organic matter decomposition.Salinity had an indirect effect on litter decomposition that was mediated through litter quality. Despite significant variation in environmental conditions along the landscape gradient, the best predictors of above- and below-ground litter decomposition were internal drivers, initial litter nitrogen content and initial litter lignin content respectively. Litter decay constants were greatest in the oligohaline marsh and declined with increasing salinity, and the fraction of litter remaining (asymptote) was greatest in the mesohaline marsh. In contrast, direct effects of salinity and flooding were positive. External drivers, salinity and flooding, stimulated cellulytic activity, which was highest in the polyhaline marsh.Synthesis. Our results indicate that as sea level rises, initial direct effects of salinity will stimulate decay of labile carbon, but over time as plant communities shift from fresh to polyhaline marsh, litter decay will decline, yielding greater potential for long-term carbon storage. These findings highlight the importance of quantifying carbon loss at multiple temporal scales, not only in coastal wetlands but also in other ecosystems where plant-mediated responses to climate change will have significant impacts on carbon cycling.

Mean age of oceanic lithosphere drives eustatic sea-level change since Pangea breakup

NASA Astrophysics Data System (ADS)

Cogné, Jean-Pascal; Humler, Eric; Courtillot, Vincent

2006-05-01

The Atlantic and Indian Oceans and the oceanic part of the Antarctic plate have formed at the expense of Panthalassa as a result of Pangea breakup over the last 180 Myr. This major plate reorganization has changed the age vs. surface distribution of oceanic lithosphere and has been a likely driver of sea-level change. Assuming that the age/surface structure of Panthalassa has remained similar to the present-day global distribution from 180 Ma to Present, and using the isochron patterns preserved in the newly formed oceans, we model resulting relative sea-level change. We find a first (slower) phase of sea-level rise (by 90 to 110 m), culminating between 120 and 50 Ma, followed by a (faster) phase of sea-level drop. We show that this result is not strongly sensitive to our hypothesis of constant mean age of Panthalassa, for which much of the information is now erased due to subduction. When the effects of oceanic plateau formation and ice cap development are added, the predicted sea-level curve fits remarkably well the first-order variations of observed sea-level change. We conclude that the changes in mean age of the oceanic lithosphere (varying between 56 and 62 ± 0.2 Myr), which are simply the expression of the Wilson cycle following Pangea breakup, are the main control, accounting for ˜ 70%, of first-order changes in sea-level.

Using simulations to forecast homeowner response to sea level rise in South Florida: Will they stay or will they go?

NASA Astrophysics Data System (ADS)

Treuer, G.

2017-12-01

Sea level rise threatens coastal communities around the world, including South Florida which may be the most financially vulnerable region in the world. Proactive investments in sea level rise adaptive flood protections could reduce South Florida's financial vulnerability. However, it is unclear if local governments and homeowners will be willing to make those investments before it is too late. Our research explores this issue by reporting the results of a novel online simulation that accelerates 348 South Florida homeowners thirty-five years into the future so that they can `live' the effects of sea level rise. The results contain a mix of optimism and caution for the prospects of future adaptation. On the positive side over 75% of participants indicated a willingness to support bond issues to pay for adaptation, even as the costs of the measures and effects of sea level rise increased over the years. Likewise, we find little evidence that politically conservative residents who normally have more skeptical views about climate change would be any less inclined to support adaptation, or only look to information sources that downplay the threat. On the negative side, homeowner interest in moving out of the region increases steadily over time as the sea level rises. This is driven by an increase in worry associated with viewing more information within the simulation.

Assessing coastal flood risk and sea level rise impacts at New York City area airports

NASA Astrophysics Data System (ADS)

Ohman, K. A.; Kimball, N.; Osler, M.; Eberbach, S.

2014-12-01

Flood risk and sea level rise impacts were assessed for the Port Authority of New York and New Jersey (PANYNJ) at four airports in the New York City area. These airports included John F. Kennedy International, LaGuardia, Newark International, and Teterboro Airports. Quantifying both present day and future flood risk due to climate change and developing flood mitigation alternatives is crucial for the continued operation of these airports. During Hurricane Sandy in October 2012 all four airports were forced to shut down, in part due to coastal flooding. Future climate change and sea level rise effects may result in more frequent shutdowns and disruptions in travel to and from these busy airports. The study examined the effects of the 1%-annual-chance coastal flooding event for present day existing conditions and six different sea level rise scenarios at each airport. Storm surge model outputs from the Federal Emergency Management Agency (FEMA) provided the present day storm surge conditions. 50th and 90thpercentile sea level rise projections from the New York Panel on Climate Change (NPCC) 2013 report were incorporated into storm surge results using linear superposition methods. These projections were evaluated for future years 2025, 2035, and 2055. In addition to the linear superposition approach for storm surge at airports where waves are a potential hazard, one dimensional wave modeling was performed to get the total water level results. Flood hazard and flood depth maps were created based on these results. In addition to assessing overall flooding at each airport, major at-risk infrastructure critical to the continued operation of the airport was identified and a detailed flood vulnerability assessment was performed. This assessment quantified flood impacts in terms of potential critical infrastructure inundation and developed mitigation alternatives to adapt to coastal flooding and future sea level changes. Results from this project are advancing the PANYNJ's understanding of the effects of sea level rise on coastal flooding at the airports and guiding decision-making in the selection of effective adaptation actions. Given the importance of these airports to transportation, this project is advancing security and continuity of national and international commerce well into the 21st century.

Tidal marsh plant responses to elevated CO2 , nitrogen fertilization, and sea level rise.

PubMed

Adam Langley, J; Mozdzer, Thomas J; Shepard, Katherine A; Hagerty, Shannon B; Patrick Megonigal, J

2013-05-01

Elevated CO2 and nitrogen (N) addition directly affect plant productivity and the mechanisms that allow tidal marshes to maintain a constant elevation relative to sea level, but it remains unknown how these global change drivers modify marsh plant response to sea level rise. Here we manipulated factorial combinations of CO2 concentration (two levels), N availability (two levels) and relative sea level (six levels) using in situ mesocosms containing a tidal marsh community composed of a sedge, Schoenoplectus americanus, and a grass, Spartina patens. Our objective is to determine, if elevated CO2 and N alter the growth and persistence of these plants in coastal ecosystems facing rising sea levels. After two growing seasons, we found that N addition enhanced plant growth particularly at sea levels where plants were most stressed by flooding (114% stimulation in the + 10 cm treatment), and N effects were generally larger in combination with elevated CO2 (288% stimulation). N fertilization shifted the optimal productivity of S. patens to a higher sea level, but did not confer S. patens an enhanced ability to tolerate sea level rise. S. americanus responded strongly to N only in the higher sea level treatments that excluded S. patens. Interestingly, addition of N, which has been suggested to accelerate marsh loss, may afford some marsh plants, such as the widespread sedge, S. americanus, the enhanced ability to tolerate inundation. However, if chronic N pollution reduces the availability of propagules of S. americanus or other flood-tolerant species on the landscape scale, this shift in species dominance could render tidal marshes more susceptible to marsh collapse. © 2013 Blackwell Publishing Ltd.

Long-memory and the sea level-temperature relationship: a fractional cointegration approach.

PubMed

Ventosa-Santaulària, Daniel; Heres, David R; Martínez-Hernández, L Catalina

2014-01-01

Through thermal expansion of oceans and melting of land-based ice, global warming is very likely contributing to the sea level rise observed during the 20th century. The amount by which further increases in global average temperature could affect sea level is only known with large uncertainties due to the limited capacity of physics-based models to predict sea levels from global surface temperatures. Semi-empirical approaches have been implemented to estimate the statistical relationship between these two variables providing an alternative measure on which to base potentially disrupting impacts on coastal communities and ecosystems. However, only a few of these semi-empirical applications had addressed the spurious inference that is likely to be drawn when one nonstationary process is regressed on another. Furthermore, it has been shown that spurious effects are not eliminated by stationary processes when these possess strong long memory. Our results indicate that both global temperature and sea level indeed present the characteristics of long memory processes. Nevertheless, we find that these variables are fractionally cointegrated when sea-ice extent is incorporated as an instrumental variable for temperature which in our estimations has a statistically significant positive impact on global sea level.

Analysis of the most recent data of Cascais Tide Gauge

NASA Astrophysics Data System (ADS)

Antunes, Carlos; Taborda, Rui; Mendes, Virgílio B.

2010-05-01

In order to meet international standards and to integrate sea level changes and tsunami monitoring networks, Cascais tide gauge, one of the oldest in the world, has been upgraded in 2003 with new acoustic equipment with digital data acquisition, temperature and air-pressure sensors, and internet connection for real time data. The new tide gauge is located very close to the old analogical gauge, which is still working. Datum links between both gauges and the permanent GPS station of Cascais were made and height differences between gauges and the GPS station have been monitored to verify site stability and to estimate the absolute vertical velocity of the site, and therefore, the absolute sea level changes. Tide gauge data from 2000 to 2009 has been analyzed and relative and absolute sea level rise rates have been estimated. The estimation of sea level rise rate with the short baseline of 10 years is made with the daily mean sea level data corrected from the inverse barometric effect. The relative sea level trend is obtained from a 60-day moving average run over the corrected daily mean sea level. The estimated rate has shown greater stability in contrast to the analysis of daily mean sea level raw data, which shows greater variability and uncertainty. Our results show a sea level rise rate of 2.6 mm/year (± 0.3 mm/year), higher than previous rates (2.1 mm/year for 1990 decade and 1.6 mm/year from 1920 to 2000), which is compatible with a sea level rise acceleration scenario. From the analysis of Cascais GPS data, for the period 1990.0 to 2010.0 we obtain an uplift rate of 0.3 mm/year leading to an absolute sea level rise of 2.9 mm/year for Cascais, under the assumption, as predicted by the ICE-5G model, that Cascais has no vertical displacement caused by the post-glacial isostatic adjustment.

Understanding Sea Level Changes

NASA Technical Reports Server (NTRS)

Chao, Benjamin F.

2004-01-01

Today more than 100 million people worldwide live on coastlines within one meter of mean sea level; any short-term or long-term sea level change relative to vertical ground motion is of great societal and economic concern. As palm-environment and historical data have clearly indicated the existence and prevalence of such changes in the past, new scientific information regarding to the nature and causes and a prediction capability are of utmost importance for the future. The 10-20 cm global sea-level rise recorded over the last century has been broadly attributed to two effects: (1) the steric effect (thermal expansion and salinity-density compensation of sea water) following global climate; (2) mass-budget changes due to a number of competing geophysical and hydrological processes in the Earth-atmosphere-hydrosphere-cryosphere system, including water exchange from polar ice sheets and mountain glaciers to the ocean, atmospheric water vapor and land hydrological variations, and anthropogenic effects such as water impoundment in artificial reservoirs and extraction of groundwater, all superimposed on the vertical motions of solid Earth due to tectonics, rebound of the mantle from past and present deglaciation, and other local ground motions. As remote-sensing tools, a number of space geodetic measurements of sea surface topography (e.g., TOPEX/Poseidon, Jason), ice mass (e.g., ICESat), time-variable gravity (e.g. GRACE), and ground motions (SLR, VLBI, GPS, InSAR, Laser altimetry, etc.) become directly relevant. Understanding sea level changes "anywhere, anytime" in a well-defined terrestrial reference frame in terms of climate change and interactions among ice masses, oceans, and the solid Earth, and being able to predict them, emerge as one of the scientific challenges in the Solid Earth Science Working Group (SESWG, 2003) conclusions.

Ten metre global sea-level change associated with South Atlantic Aptian salt deposition

NASA Technical Reports Server (NTRS)

Burke, Kevin; Sengor, A. M. Celal

1988-01-01

Catastrophic filling of the kind of subsea-level depression commonly formed during ocean opening and ocean closing is the only mechanism, other than glacial eustacy, capable of rapidly lowering sea level. Aptian evaporites overlying oceanic crust on both sides of the South Atlantic between the Walvis Ridge and the Niger Delta were deposited in such a basin by repeated spilling of ocean water. The final flooding of the South Atlantic north of the Walvis Ridge extracted about 14 x 10 to the 8th cu km of sea water from the world ocean and effected about 10 m of sea-level lowering. It is speculated that the middle Aptian unconformity, which is one of the more prominent world-wide unconformities, is associated with this sea-level drop of about 10 m. A corollary of this interpretation is that if the catastrophic sea-level lowerings during the Mesozoic era had amplitudes substantially greater than 10 m, then a glacial mechanism to explain them would seem inescapable although the stratigraphic record has not yet yielded any evidence of such glaciation.

Global increasing of mean sea level and erroneous treatment of a role of thermal factors

NASA Astrophysics Data System (ADS)

Barkin, Yu. V.

2009-04-01

Satellite methods of studies of the ocean surface - methods of altimetry - have been obtained intensive development in the last decades (since 1993). However, altimetry studies with the help of special satellites such as TOPEX-Poseidon not only have not cleared up understanding of the phenomenon of increase of sea level (SLR), but have even more confused and without that a complex question on the reasons of increase of sea level. Appeared, that classical determinations of average velocity of increase of sea level on coastal observations (1.4-1.7 mm / yr) approximately for 0.8-1.0 mm / yr it is less, rather than by modern satellite determinations of satellites TOPEX - Poseidon etc. (2.5 - 2.8 mm / yr). On the basis of the data of altimetry observations of TOPEX-Poseidon and Jason for the period 1993-2003 for geocentric velocity of increase of sea level (of global ocean) the value 2.8+/-0.4 mm / yr [1] has been obtained. In the given report the full answer is actually is given to a question put by leading experts on research of the sea level: "The TOPEX/Poseidon and Jason satellite altimeter missions provided a 12 year record of sea level change, which show increase of global mean sea level of 2.8+/-0.4 mm/yr, with considerable geographic variation. An important question for climate studies is to determine the cause of this change - specifically how much of the change is due to steric (heating) versus eustatic (runoff, melting ice, etc.) contribution?" [1]. There is, a big value of average velocity of increase of the sea level on the satellite data, it is possible to explain only by kinematical effect in data of observations. The motion of the satellite "is concerned" to the centre of mass of our planet, and its position is determined by a geocentric radius - vector. Therefore northern drift of the centre of mass in the Earth body [2] as though results in reduction of distances from the satellite up to the sea surface in the southern hemisphere and to their reduction in the northern hemisphere. At averaging of measurements over all ocean surface (mainly located in a southern hemisphere where it occupies about 80 % of the areas) there will be an effect of apparent additional increase of the sea level. Therefore this ("apparent") velocity of increase of the sea level accepts the greater value (about 2.4 mm / year) in comparison with coastal determinations of this velocity that is rather close to the data of satellite observations. The additional effect in increase of the sea level is brought by deformation of the ocean bottom. The both mentioned phenomena: the secular drift of the center of mass of the Earth and the secular expansion of southern hemisphere of the Earth have been predicted by author [2], [3] and have obtained confirmations by space geodesy methods. The offered explanation has the extremely - important value for studying a possible role of thermal and climatic factors which can not apply any more for a big component attributed to it in change of the sea level. The account of fictitious component of this velocity results practically in real value of variation of the average sea level about 1.3-1.6 mm / yr, that completely coordinate positions of researchers of ocean by coastal and altimetry (satellite) methods. Moreover, the given work opens a direct opportunity for an explanation of increase of the sea level as result of deformation of the ocean bottom. This deformation is a major factor of change of the average sea level. Water superseded in a southern hemisphere gives the significant contribution to observably value of velocity of sea level rise up to 0.8-1.2 mm / yr [3, 4]. The work fulfilled at financial support of Russian projects of RFBR: N 07-05-00939 and N 06-02-16665. This abstract (without what or changes) has been accepted to EGU GA 2008 Session IS48 "75th Anniversary of the PSML"(Convener: Woodworth P.) but was not included in its program. References. [1] Nerem R.S., Leuliette E.W., Chambers D.P. (2005) An Integrated Study of Sea Level Change Using Altimetry, Gravity, and In Situ Measurements. Geophys. Res. Abstr., Vol. 7, 09831, Sref-ID: 1607-7962/gra/EGU05-A-09831. [2] Barkin, Yu.V. (1995) About Geocenter Motion Due to Global Changes of Its Dynamical Structure and Tidal Deformations. Vestn. Mosk. Un-ta. Fiz., Astron., Vol. 36, № 5, pp. 99-101 (in Russian). [3] Barkin Yu.V. (2007) Mechanisms of increase of mean sea level and solution of "attribution problem". "Geology of seas and oceans: Materials of XVII International scientific conference (scool) on mariner geology". V. IV. M.: GEOS. 2007. p. 21-23. [4] Barkin Yu.V. (2007) Global increase of mean sea level and erroneous treatment of a role of thermal factors. "Geology of seas and oceans: Materials of XVII International scientific conference (scool) on mariner geology". V. IV. M.: GEOS. 2007. p. 18-20.

Sea Extremes: Integrated impact assessment in coastal climate adaptation

NASA Astrophysics Data System (ADS)

Sorensen, Carlo; Knudsen, Per; Broge, Niels; Molgaard, Mads; Andersen, Ole

2016-04-01

We investigate effects of sea level rise and a change in precipitation pattern on coastal flooding hazards. Historic and present in situ and satellite data of water and groundwater levels, precipitation, vertical ground motion, geology, and geotechnical soil properties are combined with flood protection measures, topography, and infrastructure to provide a more complete picture of the water-related impact from climate change at an exposed coastal location. Results show that future sea extremes evaluated from extreme value statistics may, indeed, have a large impact. The integrated effects from future storm surges and other geo- and hydro-parameters need to be considered in order to provide for the best protection and mitigation efforts, however. Based on the results we present and discuss a simple conceptual model setup that can e.g. be used for 'translation' of regional sea level rise evidence and projections to concrete impact measures. This may be used by potentially affected stakeholders -often working in different sectors and across levels of governance, in a common appraisal of the challenges faced ahead. The model may also enter dynamic tools to evaluate local impact as sea level research advances and projections for the future are updated.

Extreme Statistics of Storm Surges in the Baltic Sea

NASA Astrophysics Data System (ADS)

Kulikov, E. A.; Medvedev, I. P.

2017-11-01

Statistical analysis of the extreme values of the Baltic Sea level has been performed for a series of observations for 15-125 years at 13 tide gauge stations. It is shown that the empirical relation between value of extreme sea level rises or ebbs (caused by storm events) and its return period in the Baltic Sea can be well approximated by the Gumbel probability distribution. The maximum values of extreme floods/ebbs of the 100-year recurrence were observed in the Gulf of Finland and the Gulf of Riga. The two longest data series, observed in Stockholm and Vyborg over 125 years, have shown a significant deviation from the Gumbel distribution for the rarest events. Statistical analysis of the hourly sea level data series reveals some asymmetry in the variability of the Baltic Sea level. The probability of rises proved higher than that of ebbs. As for the magnitude of the 100-year recurrence surge, it considerably exceeded the magnitude of ebbs almost everywhere. This asymmetry effect can be attributed to the influence of low atmospheric pressure during storms. A statistical study of extreme values has also been applied to sea level series for Narva over the period of 1994-2000, which were simulated by the ROMS numerical model. Comparisons of the "simulated" and "observed" extreme sea level distributions show that the model reproduces quite satisfactorily extreme floods of "moderate" magnitude; however, it underestimates sea level changes for the most powerful storm surges.

Sensitivity of the sea ice concentration over the Kara-Barents Sea in autumn to the winter temperature variability over East Asia

NASA Astrophysics Data System (ADS)

Cho, K. H.; Chang, E. C.

2017-12-01

In this study, we performed sensitivity experiments by utilizing the Global/Regional Integrated Model system with different conditions of the sea ice concentration over the Kara-Barents (KB) Sea in autumn, which can affect winter temperature variability over East Asia. Prescribed sea ice conditions are 1) climatological autumn sea ice concentration obtained from 1982 to 2016, 2) reduced autumn sea ice concentration by 50% of the climatology, and 3) increased autumn sea ice concentration by 50% of climatology. Differently prescribed sea ice concentration changes surface albedo, which affects surface heat fluxes and near-surface air temperature. The reduced (increased) sea ice concentration over the KB sea increases (decreases) near-surface air temperature that leads the lower (higher) sea level pressure in autumn. These patterns are maintained from autumn to winter season. Furthermore, it is shown that the different sea ice concentration over the KB sea has remote effects on the sea level pressure patterns over the East Asian region. The lower (higher) sea level pressure over the KB sea by the locally decreased (increased) ice concentration is related to the higher (lower) pressure pattern over the Siberian region, which induces strengthened (weakened) cold advection over the East Asian region. From these sensitivity experiments it is clarified that the decreased (increased) sea ice concentration over the KB sea in autumn can lead the colder (warmer) surface air temperature over East Asia in winter.

Description and assessment of regional sea-level trends and variability from altimetry and tide gauges at the northern Australian coast

NASA Astrophysics Data System (ADS)

Gharineiat, Zahra; Deng, Xiaoli

2018-05-01

This paper aims at providing a descriptive view of the low-frequency sea-level changes around the northern Australian coastline. Twenty years of sea-level observations from multi-mission satellite altimetry and tide gauges are used to characterize sea-level trends and inter-annual variability over the study region. The results show that the interannual sea-level fingerprint in the northern Australian coastline is closely related to El Niño Southern Oscillation (ENSO) and Madden-Julian Oscillation (MJO) events, with the greatest influence on the Gulf Carpentaria, Arafura Sea, and the Timor Sea. The basin average of 14 tide-gauge time series is in strong agreement with the basin average of the altimeter data, with a root mean square difference of 18 mm and a correlation coefficient of 0.95. The rate of the sea-level trend over the altimetry period (6.3 ± 1.4 mm/yr) estimated from tide gauges is slightly higher than that (6.1 ± 1.3 mm/yr) from altimetry in the time interval 1993-2013, which can vary with the length of the time interval. Here we provide new insights into examining the significance of sea-level trends by applying the non-parametric Mann-Kendall test. This test is applied to assess if the trends are significant (upward or downward). Apart from a positive rate of sea-level trends are not statistically significant in this region due to the effects of natural variability. The findings suggest that altimetric trends are not significant along the coasts and some parts of the Gulf Carpentaria (14°S-8°S), where geophysical corrections (e.g., ocean tides) cannot be estimated accurately and altimeter measurements are contaminated by reflections from the land.

The contribution to future flood risk in the Severn Estuary from extreme sea level rise due to ice sheet mass loss

NASA Astrophysics Data System (ADS)

Quinn, N.; Bates, P. D.; Siddall, M.

2013-12-01

The rate at which sea levels will rise in the coming century is of great interest to decision makers tasked with developing mitigation policies to cope with the risk of coastal inundation. Accurate estimates of future sea levels are vital in the provision of effective policy. Recent reports from UK Climate Impacts Programme (UKCIP) suggest that mean sea levels in the UK may rise by as much as 80 cm by 2100; however, a great deal of uncertainty surrounds model predictions, particularly the contribution from ice sheets responding to climatic warming. For this reason, the application of semi-empirical modelling approaches for sea level rise predictions has increased of late, the results from which suggest that the rate of sea level rise may be greater than previously thought, exceeding 1 m by 2100. Furthermore, studies in the Red Sea indicate that rapid sea level rise beyond 1m per century has occurred in the past. In light of such research, the latest UKCIP assessment has included a H++ scenario for sea level rise in the UK of up to 1.9 m which is defined as improbable but, crucially, physically plausible. The significance of such low-probability sea level rise scenarios upon the estimation of future flood risk is assessed using the Somerset levels (UK) as a case study. A simple asymmetric probability distribution is constructed to include sea level rise scenarios of up to 1.9 m by 2100 which are added to a current 1:200 year event water level to force a two-dimensional hydrodynamic model of coastal inundation. From the resulting ensemble predictions an estimation of risk by 2100 is established. The results indicate that although the likelihood of extreme sea level rise due to rapid ice sheet mass loss is low, the resulting hazard can be large, resulting in a significant (27%) increase to the projected annual risk. Furthermore, current defence construction guidelines for the coming century in the UK are expected to account for 95% of the sea level rise distribution presented in this research, while the larger, low probability scenarios beyond this level are estimated to contribute a residual annual risk of approximately £0.45 million. These findings clearly demonstrate that uncertainty in future sea level rise is a vital component of coastal flood risk, and therefore, needs to be accounted for by decision makers when considering mitigation policies related to coastal flooding.

A joint analysis of sea-level and meteorological data over the past 19th and 20th century on the Charente-Maritime French Atlantic coast

NASA Astrophysics Data System (ADS)

Gouriou, Thomas; Wöppelmann, Guy

2010-05-01

A systematic survey of the historical French archives was initiated in 2004 to search for ancient sea level observations. Long term sea-level records are invaluable to study trends in sea level components in the context of climate change due to global warming. A large amount of records have been discovered, notably on the Charente-Maritime French Atlantic coast: fort Enet (1859-1873) and fort Boyard (1873-1909), a few kilometres apart. These two historical data sets include meteorological observations in addition to the sea-level heights: sea-level pressure, air temperature, wind direction and speed, and sometimes daily indications on the local climatic conditions. Sea-level heights were measured with a "Chazallon" type of float tide gauge and whereas the sea-level pressures were measured with a "Fortin" mercury barometer. The historical data sets are now in computer-accessible form. They were manually checked for consistency, and compared to nearby data sets (e.g. Brest, Hadley centre Sea Level Pressure data set HadSLP2). We will present the data sets, the composite time series that were built for the period 1859-1909, and the joint sea level and meteorological data analysis which proved worthwhile. The pressure data were indeed of particular interest (7 observations per day, from 6.00am to 9.00pm between 1859 and 1909). First, examining the inverse barometer (IB) effect was demonstrated to be a good means to check the sea-level data sets (Woodworth 2006). If the data sets were of poor quality, then the sea-level height and air pressure monthly mean time series would show low or no correlation. Conversely, if both data sets were of good quality, there would be a high negative correlation between the local sea-level heights and sea-level pressure changes. Second, a linear regression between the two parameters (sea level and atmospheric pressure) would be giving a regression coefficient of approximately -1 cm/mbar under static assumption. Any departure from this relationship is indicative of wind-driven dynamical processes. As will be shown, the Charente-Maritime French Atlantic coast is a particular environment subject to westward winds with a complex coastline and bathymetry (islands, shallow waters). Last but not least, our data archeology exercise will provide additional evidence to the intriguing relation that was first noted by Miller and Douglas (2007) between sea level on the eastern boundary of the North Atlantic and the strength of the gyre-scale circulation, as represented by air pressure in the centre of the gyre, on multi-decadal and century-timescales.

Uncertainties in Future Regional Sea Level Trends: How to Deal with the Internal Climate Variability?

NASA Astrophysics Data System (ADS)

Becker, M.; Karpytchev, M.; Hu, A.; Deser, C.; Lennartz-Sassinek, S.

2017-12-01

Today, the Climate models (CM) are the main tools for forecasting sea level rise (SLR) at global and regional scales. The CM forecasts are accompanied by inherent uncertainties. Understanding and reducing these uncertainties is becoming a matter of increasing urgency in order to provide robust estimates of SLR impact on coastal societies, which need sustainable choices of climate adaptation strategy. These CM uncertainties are linked to structural model formulation, initial conditions, emission scenario and internal variability. The internal variability is due to complex non-linear interactions within the Earth Climate System and can induce diverse quasi-periodic oscillatory modes and long-term persistences. To quantify the effects of internal variability, most studies used multi-model ensembles or sea level projections from a single model ran with perturbed initial conditions. However, large ensembles are not generally available, or too small, and computationally expensive. In this study, we use a power-law scaling of sea level fluctuations, as observed in many other geophysical signals and natural systems, which can be used to characterize the internal climate variability. From this specific statistical framework, we (1) use the pre-industrial control run of the National Center for Atmospheric Research Community Climate System Model (NCAR-CCSM) to test the robustness of the power-law scaling hypothesis; (2) employ the power-law statistics as a tool for assessing the spread of regional sea level projections due to the internal climate variability for the 21st century NCAR-CCSM; (3) compare the uncertainties in predicted sea level changes obtained from a NCAR-CCSM multi-member ensemble simulations with estimates derived for power-law processes, and (4) explore the sensitivity of spatial patterns of the internal variability and its effects on regional sea level projections.

Anomalous secular sea-level acceleration in the Baltic Sea caused by glacial isostatic adjustment

NASA Astrophysics Data System (ADS)

Spada, Giorgio; Galassi, Gaia; Olivieri, Marco

2014-05-01

Observations from the global array of tide gauges show that global sea-level has been rising at an average rate of 1.5-2 mm/yr during the last ˜ 150 years (Spada & Galassi, 2012). Although a global sea-level acceleration was initially ruled out, subsequent studies have coherently proposed values of ˜1 mm/year/century (Olivieri & Spada, 2012). More complex non-linear trends and abrupt sea-level variations have now also been recognized. Globally, they could manifest a regime shift between the late Holocene and the current rhythms of sea-level rise, while locally they result from ocean circulation anomalies, steric effects and wind stress (Bromirski et al. 2011). Although isostatic readjustment affects the local rates of secular sea-level change, a possible impact on regional acceleration have been so far discounted (Woodworth et al., 2009) since the process evolves on a millennium scale. Here we report a previously unnoticed anomaly in the long-term sea-level acceleration of the Baltic Sea tide gauge records, and we explain it by the classical post-glacial rebound theory and numerical modeling of glacial isostasy. Contrary to previous assumptions, our findings demonstrate that isostatic compensation plays a role in the regional secular sea-level acceleration. In response to glacial isostatic adjustment (GIA), tide gauge records located along the coasts of the Baltic Sea exhibit a small - but significant - long-term sea-level acceleration in excess to those in the far field of previously glaciated regions. The sign and the amplitude of the anomaly is consistent with the post-glacial rebound theory and with realistic numerical predictions of GIA models routinely employed to decontaminate the tide gauges observations from the GIA effects (Peltier, 2004). Model computations predict the existence of anomalies of similar amplitude in other regions of the globe where GIA is still particularly vigorous at present, but no long-term instrumental observations are available to support their existence. We confirm that a GIA correction for secular sea-level acceleration is not required in GSLA assessments because its average value is vanishingly small at the locations of the PSMSL tide gauges (Douglas, 1992). Nevertheless, GIA is contributing significantly on a regional scale, and therefore it should be recognized as one of the processes responsible for local, long-term sea-level acceleration. Reference: Bromirski, P.D., Miller, A.J., Flick, R.E. & Auad, G., 2011, J. Geoph. Res. 116, C07005; Douglas, B.C., 1992, J. Geoph. Res. 97, 12,699-12,706; Olivieri, M. & Spada, G., 2013, Global Planet. Change 109, 64-72; Peltier, W.R., 2004, Annu. Rev. Earth. Pl. Sc. 32, 111-149; Spada, G. & Galassi, G., 2012, Geophys. J. Int. 191, 1067-1094; Woodworth, P.L., White, N. J., Jevrejeva, S., Holgate, S. J., Church, J. A. & Gehrels, W. R., 2009, Int. J. Climatol. 29, 777-789.

Late Cretaceous to Miocene sea-level estimates from the New Jersey and Delaware coastal plain coreholes: An error analysis

USGS Publications Warehouse

Kominz, M.A.; Browning, J.V.; Miller, K.G.; Sugarman, P.J.; Mizintseva, S.; Scotese, C.R.

2008-01-01

Sea level has been estimated for the last 108 million years through backstripping of corehole data from the New Jersey and Delaware Coastal Plains. Inherent errors due to this method of calculating sea level are discussed, including uncertainties in ages, depth of deposition and the model used for tectonic subsidence. Problems arising from the two-dimensional aspects of subsidence and response to sediment loads are also addressed. The rates and magnitudes of sea-level change are consistent with at least ephemeral ice sheets throughout the studied interval. Million-year sea-level cycles are, for the most part, consistent within the study area suggesting that they may be eustatic in origin. This conclusion is corroborated by correlation between sequence boundaries and unconformities in New Zealand. The resulting long-term curve suggests that sea level ranged from about 75-110 m in the Late Cretaceous, reached a maximum of about 150 m in the Early Eocene and fell to zero in the Miocene. The Late Cretaceous long-term (107 years) magnitude is about 100-150 m less than sea level predicted from ocean volume. This discrepancy can be reconciled by assuming that dynamic topography in New Jersey was driven by North America overriding the subducted Farallon plate. However, geodynamic models of this effect do not resolve the problem in that they require Eocene sea level to be significantly higher in the New Jersey region than the global average. ?? 2008 The Authors. Journal compilation ?? 2008 Blackwell Publishing.

Effects of El Niño-Southern Oscillation on sea level anomalies along the Gulf of Mexico coast

NASA Astrophysics Data System (ADS)

Kennedy, Andrew J.; Griffin, Melissa L.; Morey, Steven L.; Smith, Shawn R.; O'Brien, James J.

2007-05-01

Analyses of daily sea level data show the impacts of El Niño-Southern Oscillation (ENSO) in the Gulf of Mexico (GOM). Data from three stations (St. Petersburg, Florida, Pensacola, Florida, and Galveston, Texas), all of which have at least 50 years of daily observations, are processed to identify the interannual signals. Although low frequency (interannual) signals in the sea level anomaly time series are not clearly evident, a low frequency modulation of the extreme anomaly events (upper 10% or lower 10% of the distributions) is identified. Results show that sea level variability is seasonally dependent at all stations, with maximum variability in the winter months. In the eastern GOM, low sea level events in the winter months are more frequent during El Niño (warm phase) conditions when compared to a neutral ENSO phase. This is consistent with ENSO-related changes in the location where extratropical atmospheric low pressure systems form and in the tracks of these weather systems. The impacts of tropical systems in the summer through early fall months on coastal sea level in the GOM are shown by infrequent extreme high and low anomalies coinciding with individual storms. However, the number of storms affecting the data record from a particular sea level station is too small to confirm ENSO-related variability. Statistical methods are employed to demonstrate a significant link between extreme sea level anomalies in the GOM and ENSO during the October to March period.

Sea Level Rise Impacts On Infrastructure Vulnerability

NASA Astrophysics Data System (ADS)

Pasqualini, D.; Mccown, A. W.; Backhaus, S.; Urban, N. M.

2015-12-01

Increase of global sea level is one of the potential consequences of climate change and represents a threat for the U.S.A coastal regions, which are highly populated and home of critical infrastructures. The potential danger caused by sea level rise may escalate if sea level rise is coupled with an increase in frequency and intensity of storms that may strike these regions. These coupled threats present a clear risk to population and critical infrastructure and are concerns for Federal, State, and particularly local response and recovery planners. Understanding the effect of sea level rise on the risk to critical infrastructure is crucial for long planning and for mitigating potential damages. In this work we quantify how infrastructure vulnerability to a range of storms changes due to an increase of sea level. Our study focuses on the Norfolk area of the U.S.A. We assess the direct damage of drinking water and wastewater facilities and the power sector caused by a distribution of synthetic hurricanes. In addition, our analysis estimates indirect consequences of these damages on population and economic activities accounting also for interdependencies across infrastructures. While projections unanimously indicate an increase in the rate of sea level rise, the scientific community does not agree on the size of this rate. Our risk assessment accounts for this uncertainty simulating a distribution of sea level rise for a specific climate scenario. Using our impact assessment results and assuming an increase of future hurricanes frequencies and intensities, we also estimate the expected benefits for critical infrastructure.

White Paper: Summary of the NOAA Workshop - Ecological Effect of Sea Level Rise in the Florida Panhandle and Coastal Alabama: Research and Modeling Needs

EPA Science Inventory

The Center for Sponsored Coastal Ocean Research (CSCOR) is addressing current and future impacts to ecological systems due to the long term effect of sea level rise due to climate change and subsidence on coastal ecosystems through the peer-reviewed research program, the Ecologic...

Rhode Island Salt Marshes: Elevation Capital and Resilience to Sea Level Rise

EPA Science Inventory

Tidal salt marsh is especially sensitive to deterioration due to the effects of accelerated sea level rise when combined with other anthropogenically linked stressors, including crab herbivory, changes in tidal hydrology, nutrient loading, dam construction, changes in temperature...

Infrastructure effects on estuarine wetlands increase their vulnerability to sea level rise

NASA Astrophysics Data System (ADS)

Rodriguez, Jose; Saco, Patricia; Sandi, Steven; Saintilan, Neil; Riccardi, Gerardo

2017-04-01

At the regional and global scales, coastal management and planning for future sea level rise scenarios is typically supported by modelling tools that predict the expected inundation extent. These tools rely on a number of simplifying assumptions that, in some cases, may result in important miscalculation of the inundation effects. One of such cases is estuarine wetlands, where vegetation strongly depends on both the magnitude and the timing of inundation. Many coastal wetlands display flow restrictions due to infrastructure or drainage works, which produce alterations to the inundation patterns that can not be captured by conventional models. In this contribution we explore the effects of flow restrictions on inundation patterns under sea level rise conditions in estuarine wetlands. We use a spatially-distributed dynamic wetland ecogeomorphological model that not only incorporates the effects of flow restrictions due to culverts, bridges and weirs as well as vegetation, but also considers that vegetation changes as a consequence of increasing inundation. We also consider the ability of vegetation to capture sediment and produce accretion. We apply our model to an estuarine wetland in Australia and show that our model predicts a much faster wetland loss due to sea level rise than conventional approaches.

Effects of wave-induced forcing on a circulation model of the North Sea

NASA Astrophysics Data System (ADS)

Staneva, Joanna; Alari, Victor; Breivik, Øyvind; Bidlot, Jean-Raymond; Mogensen, Kristian

2017-04-01

The effect of wind waves on water level and currents during two storms in the North Sea is investigated using a high-resolution NEMO model forced with fluxes and fields from a high-resolution wave model. The additional terms accounting for wave-current interaction that are considered in this study are the Stokes-Coriolis force and the sea-state dependent energy and momentum fluxes. The individual and collective role of these processes is quantified and the results are compared with a control run without wave effects as well as against current and water level measurements from coastal stations. We find a better agreement with observations when the circulation model is forced by sea-state dependent fluxes, especially in extreme events. The two extreme events, the storm Christian (25-27 October 2013), and about a month later, the storm Xaver (5-7 December 2013), induce different wave and surge conditions over the North Sea. Including the wave effects in the circulation model for the storm Xaver raises the modelled surge by more than 40 cm compared with the control run in the German Bight area. For the storm Christian, a difference of 20-30 cm in the surge level between the wave-forced and the stand-alone ocean model is found over the whole southern part of the North Sea. Moreover, the modelled vertical velocity profile fits the observations very well when the wave forcing is accounted for. The contribution of wave-induced forcing has been quantified indicating that this represents an important mechanism for improving water level and current predictions.

Effects of wave-induced forcing on a circulation model of the North Sea

NASA Astrophysics Data System (ADS)

Staneva, Joanna; Alari, Victor; Breivik, Øyvind; Bidlot, Jean-Raymond; Mogensen, Kristian

2017-01-01

The effect of wind waves on water level and currents during two storms in the North Sea is investigated using a high-resolution Nucleus for European Modelling of the Ocean (NEMO) model forced with fluxes and fields from a high-resolution wave model. The additional terms accounting for wave-current interaction that are considered in this study are the Stokes-Coriolis force, the sea-state-dependent energy and momentum fluxes. The individual and collective role of these processes is quantified and the results are compared with a control run without wave effects as well as against current and water-level measurements from coastal stations. We find a better agreement with observations when the circulation model is forced by sea-state-dependent fluxes, especially in extreme events. The two extreme events, the storm Christian (25-27 October 2013), and about a month later, the storm Xaver (5-7 December 2013), induce different wave and surge conditions over the North Sea. Including the wave effects in the circulation model for the storm Xaver raises the modelled surge by more than 40 cm compared with the control run in the German Bight area. For the storm Christian, a difference of 20-30 cm in the surge level between the wave-forced and the stand-alone ocean model is found over the whole southern part of the North Sea. Moreover, the modelled vertical velocity profile fits the observations very well when the wave forcing is accounted for. The contribution of wave-induced forcing has been quantified indicating that this represents an important mechanism for improving water-level and current predictions.

Rapid Settlement of Majuro Atoll, Central Pacific, Following its Emergence 2000 Years Ago

NASA Astrophysics Data System (ADS)

Kayanne, H.; Yamaguchi, T.; Yamano, H.; Yoneda, M.

2010-12-01

Atoll islands are areas of low, flat land, and the sustainability of habitable land in such environments is sensitive to even slight changes in sea level. The rise in sea level projected to occur during this century may lead to the submergence of atoll islands and the widespread loss of habitable land. However, the actual time sequence of past sea level change, island emergence events, and human settlement of newly emerged islands remain poorly constrained. Our excavation survey, combined with calibrated radiocarbon age dates, at Majuro Atoll, Marshall Islands, central Pacific, reveals that emergence of the island, triggered by a fall in sea level, was quickly followed by human settlement. The elevation of the central body of the island exceeded high water level at 2000 years ago, and the complete formation of the island occurred within an interval of 100 years. The island was colonized by people shortly after emergence, at 2000 years ago, prior to the establishment of dense vegetation, and has been continuously settled since that time. Habitable land was created by a fall in sea level, and any future rise in sea level will have a reverse effect, resulting in a loss of habitable land on atoll islands.

Late Pleistocene Sea level on the New Jersey Margin: Implications to eustasy and deep-sea temperature

USGS Publications Warehouse

Wright, J.D.; Sheridan, R.E.; Miller, K.G.; Uptegrove, J.; Cramer, B.S.; Browning, J.V.

2009-01-01

We assembled and dated a late Pleistocene sea-level record based on sequence stratigraphy from the New Jersey margin and compared it with published records from fossil uplifted coral reefs in New Guinea, Barbados, and Araki Island, as well as a composite sea-level estimate from scaling of Red Sea isotopic values. Radiocarbon dates, amino acid racemization data, and superposition constrain the ages of large (20-80??m) sea-level falls from New Jersey that correlate with Marine Isotope Chrons (MIC) 2, 3b, 4, 5b, and 6 (the past 130??kyr). The sea-level records for MIC 1, 2, 4, 5e, and 6 are similar to those reported from New Guinea, Barbados, Araki, and the Red Sea; some differences exist among records for MIC 3. Our record consistently provides the shallowest sea level estimates for MIC3 (??? 25-60??m below present); it agrees most closely with the New Guinea record of Chappell (2002; ??? 35-70??m), but contrasts with deeper estimates provided by Araki (??? 85-95??m) and the Red Sea (50-90??m). Comparison of eustatic estimates with benthic foraminiferal ??18O records shows that the deep sea cooled ??? 2.5????C between MIC 5e and 5d (??? 120-110??ka) and that near freezing conditions persisted until Termination 1a (14-15??ka). Sea-level variations between MIC 5b and 2 (ca. 90-20??ka) follow a well-accepted 0.1???/10??m linear variation predicted by ice-growth effects on foraminiferal ??18O values. The pattern of deep-sea cooling follows a previously established hysteresis loop between two stable modes of operation. Cold, near freezing deep-water conditions characterize most of the past 130??kyr punctuated only by two warm intervals (the Holocene/MIC 1 and MIC 5e). We link these variations to changes in Northern Component Water (NCW). ?? 2009 Elsevier B.V. All rights reserved.

Sea level during the Phanerozoic - what causes the fluctuations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harrison, C.G.A.

1985-01-01

All possible causes of sea level change have been analyzed in order to explain the fall of sea level since the Cretaceous. The most important effect is the decrease in volume of the ridge crests due to an overall decrease in the rate of spreading since the Cretaceous. Other factors in order of decreasing importance are the reduction of the thermal bulge which accompanied the episode of Pacific volcanism between 110 and 70 my bp, the production of continental ice, the effect of the collision of India with Asia, and cooling of the ocean water. Sedimentation variation in the deepmore » ocean has the effect of raising sea level a modest amount. The net variation in sea level during the past 80 million years has been a reduction by about 280 m after having allowed for isostatic adjustment of the ocean floor. This is considerably larger, than sea level calculated from the amount of continental flooding, and it is proposed that the discrepancy is due to a change in the continental hypsographic curve following the breakup of Pangea. This hypothesis is born out by studies of flooding during the Phanerozoic which reveal that flooding was very low at the beginning of the Mesozoic during a time of continental agglomeration, and high during much of the Paleozoic, which was a time of continental separation. In the Cambrian there is evidence for an increase in flooding with time, and at the beginning of the Cambrian flooding was not much greater than at the beginning of the Mesozoic, suggesting that it marked a time just subsequent to the break up of a super continent.« less

Respiratory function in pregnancy at sea level and at high altitude.

PubMed

McAuliffe, Fionnuala; Kametas, Nikos; Espinoza, Jimmy; Greenough, Anne; Nicolaides, Kypros

2004-04-01

To determine the effect of pregnancy on respiratory function in a non-Caucasian group and determine whether there was an interaction between pregnancy and altitude of residence. Prospective cross sectional study. Antenatal clinics in Peru, at sea level in Lima and at high altitude in Cerro de Pasco. Peruvian women with singleton pregnancies; 122 living at sea level and 192 living at 4300 m altitude in the Peruvian Andes. At each location, 19 non-pregnant women were also studied. Respiratory function was measured in pregnant and non-pregnant women living at sea level and at 4300 m. Forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), peak expiratory flow rate (PEFR), total lung capacity (TLC), inspiratory capacity (IC), residual volume (RV), expiratory residual volume (ERV) and functional residual capacity (FRC). At sea level, RV and TLC were higher in the third compared with the first trimester (P < 0.05). At high altitude, FEV1 (P < 0.01), ERV (P < 0.01) and FRC (P < 0.01) were lower in the third compared with the first trimester. Pregnant and non-pregnant women at high altitude were 4 cm shorter (P < 0.0001) and had larger lung volumes (P < 0.01); their total lung capacities were approximately 1 L greater than women living at sea level (P < 0.0001). These results suggest that the effect of pregnancy on the respiratory function of healthy women is influenced by altitude of residence.

High-resolution tide projections reveal extinction threshold in response to sea-level rise.

PubMed

Field, Christopher R; Bayard, Trina S; Gjerdrum, Carina; Hill, Jason M; Meiman, Susan; Elphick, Chris S

2017-05-01

Sea-level rise will affect coastal species worldwide, but models that aim to predict these effects are typically based on simple measures of sea level that do not capture its inherent complexity, especially variation over timescales shorter than 1 year. Coastal species might be most affected, however, by floods that exceed a critical threshold. The frequency and duration of such floods may be more important to population dynamics than mean measures of sea level. In particular, the potential for changes in the frequency and duration of flooding events to result in nonlinear population responses or biological thresholds merits further research, but may require that models incorporate greater resolution in sea level than is typically used. We created population simulations for a threatened songbird, the saltmarsh sparrow (Ammodramus caudacutus), in a region where sea level is predictable with high accuracy and precision. We show that incorporating the timing of semidiurnal high tide events throughout the breeding season, including how this timing is affected by mean sea-level rise, predicts a reproductive threshold that is likely to cause a rapid demographic shift. This shift is likely to threaten the persistence of saltmarsh sparrows beyond 2060 and could cause extinction as soon as 2035. Neither extinction date nor the population trajectory was sensitive to the emissions scenarios underlying sea-level projections, as most of the population decline occurred before scenarios diverge. Our results suggest that the variation and complexity of climate-driven variables could be important for understanding the potential responses of coastal species to sea-level rise, especially for species that rely on coastal areas for reproduction. © 2016 John Wiley & Sons Ltd.

Potential effects of sea-level rise on coastal wetlands in southeastern Louisiana

USGS Publications Warehouse

Glick, Patty; Clough, Jonathan; Polaczyk, Amy; Couvillion, Brady R.; Nunley, Brad

2013-01-01

Coastal Louisiana wetlands contain about 37% of the estuarine herbaceous marshes in the conterminous United States. The long-term stability of coastal wetlands is often a function of a wetland's ability to maintain elevation equilibrium with mean sea level through processes such as primary production and sediment accretion. However, Louisiana has sustained more coastal wetland loss than all other states in the continental United States combined due to a combination of natural and anthropogenic factors, including sea-level rise. This study investigates the potential impact of current and accelerating sea-level rise rates on key coastal wetland habitats in southeastern Louisiana using the Sea Level Affecting Marshes Model (SLAMM). Model calibration was conducted using a 1956–2007 observation period and hindcasting results predicted 35% versus observed 39% total marsh loss. Multiple sea-level-rise scenarios were then simulated for the period of 2007–2100. Results indicate a range of potential wetland losses by 2100, from an additional 2,188.97 km2 (218,897 ha, 9% of the 2007 wetland area) under the lowest sea-level-rise scenario (0.34 m), to a potential loss of 5,875.27 km2 (587,527 ha, 24% of the 2007 wetland area) in the highest sea-level-rise scenario (1.9 m). Model results suggest that one area of particular concern is the potential vulnerability of the region's baldcypress-water tupelo (Taxodium distichum-Nyssa aquatica) swamp habitat, much of which is projected to become permanently flooded (affecting regeneration) under all modeled scenarios for sea-level rise. These findings will aid in the development of ecosystem management plans that support the processes and conditions that result in sustainable coastal ecosystems.

Adapting to Rising Sea Level: A Florida Perspective

NASA Astrophysics Data System (ADS)

Parkinson, Randall W.

2009-07-01

Global climate change and concomitant rising sea level will have a profound impact on Florida's coastal and marine systems. Sea-level rise will increase erosion of beaches, cause saltwater intrusion into water supplies, inundate coastal marshes and other important habitats, and make coastal property more vulnerable to erosion and flooding. Yet most coastal areas are currently managed under the premise that sea-level rise is not significant and the shorelines are static or can be fixed in place by engineering structures. The new reality of sea-level rise and extreme weather due to climate change requires a new style of planning and management to protect resources and reduce risk to humans. Scientists must: (1) assess existing coastal vulnerability to address short term management issues and (2) model future landscape change and develop sustainable plans to address long term planning and management issues. Furthermore, this information must be effectively transferred to planners, managers, and elected officials to ensure their decisions are based upon the best available information. While there is still some uncertainty regarding the details of rising sea level and climate change, development decisions are being made today which commit public and private investment in real estate and associated infrastructure. With a design life of 30 yrs to 75 yrs or more, many of these investments are on a collision course with rising sea level and the resulting impacts will be significant. In the near term, the utilization of engineering structures may be required, but these are not sustainable and must ultimately yield to "managed withdrawal" programs if higher sea-level elevations or rates of rise are forthcoming. As an initial step towards successful adaptation, coastal management and planning documents (i.e., comprehensive plans) must be revised to include reference to climate change and rising sea-level.

The effect of sediment loading in Fennoscandia and the Barents Sea during the last glacial cycle on glacial isostatic adjustment observations

NASA Astrophysics Data System (ADS)

van der Wal, Wouter; IJpelaar, Thijs

2017-09-01

Models for glacial isostatic adjustment (GIA) routinely include the effects of meltwater redistribution and changes in topography and coastlines. Since the sediment transport related to the dynamics of ice sheets may be comparable to that of sea level rise in terms of surface pressure, the loading effect of sediment deposition could cause measurable ongoing viscous readjustment. Here, we study the loading effect of glacially induced sediment redistribution (GISR) related to the Weichselian ice sheet in Fennoscandia and the Barents Sea. The surface loading effect and its effect on the gravitational potential is modeled by including changes in sediment thickness in the sea level equation following the method of Dalca et al. (2013). Sediment displacement estimates are estimated in two different ways: (i) from a compilation of studies on local features (trough mouth fans, large-scale failures, and basin flux) and (ii) from output of a coupled ice-sediment model. To account for uncertainty in Earth's rheology, three viscosity profiles are used. It is found that sediment transport can lead to changes in relative sea level of up to 2 m in the last 6000 years and larger effects occurring earlier in the deglaciation. This magnitude is below the error level of most of the relative sea level data because those data are sparse and errors increase with length of time before present. The effect on present-day uplift rates reaches a few tenths of millimeters per year in large parts of Norway and Sweden, which is around the measurement error of long-term GNSS (global navigation satellite system) monitoring networks. The maximum effect on present-day gravity rates as measured by the GRACE (Gravity Recovery and Climate Experiment) satellite mission is up to tenths of microgal per year, which is larger than the measurement error but below other error sources. Since GISR causes systematic uplift in most of mainland Scandinavia, including GISR in GIA models would improve the interpretation of GNSS and GRACE observations there.

Assessing the impact of sea level rise due to climate change on seawater intrusion in Mekong Delta, Vietnam.

PubMed

Vu, D T; Yamada, T; Ishidaira, H

2018-03-01

In the context of climate change, salinity intrusion into rivers has been, and will be, one of the most important issues for coastal water resources management. A combination of changes, including increased temperature, change in regional rainfall, especially sea level rise (SLR) related to climate change, will have significant impacts on this phenomenon. This paper presents the outcomes of a study conducted in the Mekong Delta of Vietnam (MKD) for evaluating the effect of sea water intrusion under a new SLR scenario. Salinity intrusion was simulated by one-dimensional (1D) modeling. The relative sea level projection was constructed corresponding to the RCP 6.0 emission scenario for MKD based on the statistical downscaling method. The sea level in 2050 is projected to increase from 25 cm to 30 cm compared to the baseline period (in 2000). Furthermore, the simulated results suggested that salinity greater than 4 g/l, which affects rice yield, will intrude up to 50-60 km into the river. Approximately 30,000 ha of agricultural area will be affected if the sea level rise is 30 cm.

Predicting location-specific extreme coastal floods in the future climate by introducing a probabilistic method to calculate maximum elevation of the continuous water mass caused by a combination of water level variations and wind waves

NASA Astrophysics Data System (ADS)

Leijala, Ulpu; Björkqvist, Jan-Victor; Johansson, Milla M.; Pellikka, Havu

2017-04-01

Future coastal management continuously strives for more location-exact and precise methods to investigate possible extreme sea level events and to face flooding hazards in the most appropriate way. Evaluating future flooding risks by understanding the behaviour of the joint effect of sea level variations and wind waves is one of the means to make more comprehensive flooding hazard analysis, and may at first seem like a straightforward task to solve. Nevertheless, challenges and limitations such as availability of time series of the sea level and wave height components, the quality of data, significant locational variability of coastal wave height, as well as assumptions to be made depending on the study location, make the task more complicated. In this study, we present a statistical method for combining location-specific probability distributions of water level variations (including local sea level observations and global mean sea level rise) and wave run-up (based on wave buoy measurements). The goal of our method is to obtain a more accurate way to account for the waves when making flooding hazard analysis on the coast compared to the approach of adding a separate fixed wave action height on top of sea level -based flood risk estimates. As a result of our new method, we gain maximum elevation heights with different return periods of the continuous water mass caused by a combination of both phenomena, "the green water". We also introduce a sensitivity analysis to evaluate the properties and functioning of our method. The sensitivity test is based on using theoretical wave distributions representing different alternatives of wave behaviour in relation to sea level variations. As these wave distributions are merged with the sea level distribution, we get information on how the different wave height conditions and shape of the wave height distribution influence the joint results. Our method presented here can be used as an advanced tool to minimize over- and underestimation of the combined effect of sea level variations and wind waves, and to help coastal infrastructure planning and support smooth and safe operation of coastal cities in a changing climate.

Orthogonal stack of global tide gauge sea level data

NASA Technical Reports Server (NTRS)

Trupin, A.; Wahr, J.

1990-01-01

Yearly and monthly tide gauge sea level data from around the globe are fitted to numerically generated equilibrium tidal data to search for the 18.6 year lunar tide and 14 month pole tide. Both tides are clearly evident in the results, and their amplitudes and phases are found to be consistent with a global equilibrium response. Global, monthly sea level data from outside the Baltic sea and Gulf of Bothnia are fitted to global atmospheric pressure data to study the response of the ocean to pressure fluctuations. The response is found to be inverted barometer at periods greater than two months. Global averages of tide gauge data, after correcting for the effects of post glacial rebound on individual station records, reveal an increase in sea level over the last 80 years of between 1.1 mm/yr and 1.9 mm/yr.

Examining effects of sea level rise and marsh crabs on Spartina patens using mesocosms

EPA Science Inventory

Coastal salt marshes provide essential ecosystem services but face increasing threats from habitat loss, eutrophication, changing precipitation patterns, and accelerating rates of sea level rise (SLR). Recent studies have suggested that herbivory and burrowing by native salt mars...

Multiple stressors and the potential for synergistic loss of New England salt marshes

PubMed Central

Angelini, Christine; Bertness, Mark D.

2017-01-01

Climate change and other anthropogenic stressors are converging on coastal ecosystems worldwide. Understanding how these stressors interact to affect ecosystem structure and function has immediate implications for coastal planning, however few studies quantify stressor interactions. We examined past and potential future interactions between two leading stressors on New England salt marshes: sea-level rise and marsh crab (Sesarma reticulatum) grazing driven low marsh die-off. Geospatial analyses reveal that crab-driven die-off has led to an order of magnitude more marsh loss than sea-level rise between 2005 and 2013. However, field transplant experimental results suggest that sea-level rise will facilitate crab expansion into higher elevation marsh platforms by inundating and gradually softening now-tough high marsh peat, exposing large areas to crab-driven die-off. Taking interactive effects of marsh softening and concomitant overgrazing into account, we estimate that even modest levels of sea-level rise will lead to levels of salt marsh habitat loss that are 3x greater than the additive effects of sea-level rise and crab-driven die-off would predict. These findings highlight the importance of multiple stressor studies in enhancing mechanistic understanding of ecosystem vulnerabilities to future stress scenarios and encourage managers to focus on ameliorating local stressors to break detrimental synergisms, reduce future ecosystem loss, and enhance ecosystem resilience to global change. PMID:28859097

Multiple stressors and the potential for synergistic loss of New England salt marshes.

PubMed

Crotty, Sinead M; Angelini, Christine; Bertness, Mark D

2017-01-01

Climate change and other anthropogenic stressors are converging on coastal ecosystems worldwide. Understanding how these stressors interact to affect ecosystem structure and function has immediate implications for coastal planning, however few studies quantify stressor interactions. We examined past and potential future interactions between two leading stressors on New England salt marshes: sea-level rise and marsh crab (Sesarma reticulatum) grazing driven low marsh die-off. Geospatial analyses reveal that crab-driven die-off has led to an order of magnitude more marsh loss than sea-level rise between 2005 and 2013. However, field transplant experimental results suggest that sea-level rise will facilitate crab expansion into higher elevation marsh platforms by inundating and gradually softening now-tough high marsh peat, exposing large areas to crab-driven die-off. Taking interactive effects of marsh softening and concomitant overgrazing into account, we estimate that even modest levels of sea-level rise will lead to levels of salt marsh habitat loss that are 3x greater than the additive effects of sea-level rise and crab-driven die-off would predict. These findings highlight the importance of multiple stressor studies in enhancing mechanistic understanding of ecosystem vulnerabilities to future stress scenarios and encourage managers to focus on ameliorating local stressors to break detrimental synergisms, reduce future ecosystem loss, and enhance ecosystem resilience to global change.

The Impact of Sea Level Rise on Geodetic Vertical Datum of Peninsular Malaysia

NASA Astrophysics Data System (ADS)

Din, A. H. M.; Abazu, I. C.; Pa'suya, M. F.; Omar, K. M.; Hamid, A. I. A.

2016-09-01

Sea level rise is rapidly turning into major issues among our community and all levels of the government are working to develop responses to ensure these matters are given the uttermost attention in all facets of planning. It is more interesting to understand and investigate the present day sea level variation due its potential impact, particularly on our national geodetic vertical datum. To determine present day sea level variation, it is vital to consider both in-situ tide gauge and remote sensing measurements. This study presents an effort to quantify the sea level rise rate and magnitude over Peninsular Malaysia using tide gauge and multi-mission satellite altimeter. The time periods taken for both techniques are 32 years (from 1984 to 2015) for tidal data and 23 years (from 1993 to 2015) for altimetry data. Subsequently, the impact of sea level rise on Peninsular Malaysia Geodetic Vertical Datum (PMGVD) is evaluated in this study. the difference between MSL computed from 10 years (1984 - 1993) and 32 years (1984 - 2015) tidal data at Port Kelang showed that the increment of sea level is about 27mm. The computed magnitude showed an estimate of the long-term effect a change in MSL has on the geodetic vertical datum of Port Kelang tide gauge station. This will help give a new insight on the establishment of national geodetic vertical datum based on mean sea level data. Besides, this information can be used for a wide variety of climatic applications to study environmental issues related to flood and global warming in Malaysia.

Revisiting Tectonic Corrections Applied to Pleistocene Sea-Level Highstands

NASA Astrophysics Data System (ADS)

Creveling, J. R.; Mitrovica, J. X.; Hay, C.; Austermann, J.; Kopp, R. E.

2015-12-01

The robustness of stratigraphic- and geomorphic-based inferences of Quaternary peak interglacial sea levels — and equivalent minimum continental ice volumes — depends on the accuracy with which highstand markers can be corrected for vertical tectonic displacement. For sites that preserve a Marine Isotope Stage (MIS) 5e sea-level highstand marker, the customary method for estimating tectonic uplift/subsidence rate computes the difference between the local elevation of the highstand marker and a reference eustatic (i.e., global mean) MIS 5e sea-level height, typically assumed to be +6 m, and then divides this height difference by the age of the highstand marker. This rate is then applied to correct the elevation of other observed sea-level markers at that site for tectonic displacement. Subtracting a reference eustatic value from a local MIS 5e highstand marker elevation introduces two potentially significant errors. First, the commonly adopted peak eustatic MIS 5e sea-level value (i.e., +6 m) is likely too low; recent studies concluded that MIS 5e peak eustatic sea level was ~6-9 m. Second, local peak MIS 5e sea level was not globally uniform, but instead characterized by significant departures from eustasy due to glacial isostatic adjustment (GIA) in response to successive glacial-interglacial cycles and excess polar ice-sheet melt relative to present day. We present numerical models of GIA that incorporate both of these effects in order to quantify the plausible range in error of previous tectonic corrections. We demonstrate that, even far from melting ice sheets, local peak MIS 5e sea level may have departed from eustasy by 2-4 m, or more. Thus, adopting an assumed reference eustatic value to estimate tectonic displacement, rather than a site-specific GIA signal, can introduce significant error in estimates of peak eustatic sea level (and minimum ice volumes) during Quaternary highstands (e.g., MIS 11, MIS 5c and MIS 5a).

Revisiting sea level changes in the North Sea during the Anthropocene

NASA Astrophysics Data System (ADS)

Jensen, Jürgen; Dangendorf, Sönke; Wahl, Thomas; Niehüser, Sebastian

2016-04-01

The North Sea is one of the best instrumented ocean basins in the world. Here we revisit sea level changes in the North Sea region from tide gauges, satellite altimetry, hydrographic profiles and ocean reanalysis data from the beginning of the 19th century to present. This includes an overview of the sea level chapter of the North Sea Climate Change Assessment (NOSCCA) complemented by results from more recent investigations. The estimates of long-term changes from tide gauge records are significantly affected by vertical land motion (VLM), which is related to both the large-scale viscoelastic response of the solid earth to ice melting since the last deglaciation and local effects. Removing VLM (estimated from various data sources such as GPS, tide gauge minus altimetry and GIA) significantly reduces the spatial variability of long-term trends in the basin. VLM corrected tide gauge records suggest a transition from relatively moderate changes in the 19th century towards modern trends of roughly 1.5 mm/yr during the 20th century. Superimposed on the long-term changes there is a considerable inter-annual to multi-decadal variability. On inter-annual timescales this variability mainly reflects the barotropic response of the ocean to atmospheric forcing with the inverted barometer effect dominating along the UK and Norwegian coastlines and wind forcing controlling the southeastern part of the basin. The decadal variability is mostly remotely forced and dynamically linked to the North Atlantic via boundary waves in response to long-shore winds along the continental slope. These findings give valuable information about the required horizontal resolution of ocean models and the necessary boundary conditions and are therefore important for the dynamical downscaling of sea level projections for the North Sea coastlines.

Managing for No Net Loss of Ecological Services: An Approach for Quantifying Loss of Coastal Wetlands due to Sea Level Rise

NASA Astrophysics Data System (ADS)

Kassakian, Jennifer; Jones, Ann; Martinich, Jeremy; Hudgens, Daniel

2017-05-01

Sea level rise has the potential to substantially alter the extent and nature of coastal wetlands and the critical ecological services they provide. In making choices about how to respond to rising sea level, planners are challenged with weighing easily quantified risks (e.g., loss of property value due to inundation) against those that are more difficult to quantify (e.g., loss of primary production or carbon sequestration services provided by wetlands due to inundation). Our goal was to develop a cost-effective, appropriately-scaled, model-based approach that allows planners to predict, under various sea level rise and response scenarios, the economic cost of wetland loss—with the estimates proxied by the costs of future restoration required to maintain the existing level of wetland habitat services. Our approach applies the Sea Level Affecting Marshes Model to predict changes in wetland habitats over the next century, and then applies Habitat Equivalency Analysis to predict the cost of restoration projects required to maintain ecological services at their present, pre-sea level rise level. We demonstrate the application of this approach in the Delaware Bay estuary and in the Indian River Lagoon (Florida), and discuss how this approach can support future coastal decision-making.

Managing for No Net Loss of Ecological Services: An Approach for Quantifying Loss of Coastal Wetlands due to Sea Level Rise.

PubMed

Kassakian, Jennifer; Jones, Ann; Martinich, Jeremy; Hudgens, Daniel

2017-05-01

Sea level rise has the potential to substantially alter the extent and nature of coastal wetlands and the critical ecological services they provide. In making choices about how to respond to rising sea level, planners are challenged with weighing easily quantified risks (e.g., loss of property value due to inundation) against those that are more difficult to quantify (e.g., loss of primary production or carbon sequestration services provided by wetlands due to inundation). Our goal was to develop a cost-effective, appropriately-scaled, model-based approach that allows planners to predict, under various sea level rise and response scenarios, the economic cost of wetland loss-with the estimates proxied by the costs of future restoration required to maintain the existing level of wetland habitat services. Our approach applies the Sea Level Affecting Marshes Model to predict changes in wetland habitats over the next century, and then applies Habitat Equivalency Analysis to predict the cost of restoration projects required to maintain ecological services at their present, pre-sea level rise level. We demonstrate the application of this approach in the Delaware Bay estuary and in the Indian River Lagoon (Florida), and discuss how this approach can support future coastal decision-making.

Integrating spatial data and shorebird nesting locations to predict the potential future impact of global warming on coastal habitats: A case study on Farasan Islands, Saudi Arabia.

PubMed

Alrashidi, Monif; Shobrak, Mohammed; Al-Eissa, Mohammed S; Székely, Tamás

2012-07-01

One of the expected effects of the global warming is changing coastal habitats by accelerating the rate of sea level rise. Coastal habitats support large number of marine and wetland species including shorebirds (plovers, sandpipers and allies). In this study, we investigate how coastal habitats may be impacted by sea level rise in the Farasan Islands, Kingdom of Saudi Arabia. We use Kentish plover Charadrius alexandrinus - a common coastal breeding shorebird - as an ecological model species to predict the influence of sea level rise. We found that any rise of sea level is likely to inundate 11% of Kentish plover nests. In addition, 5% of the coastal areas of Farasan Islands, which support 26% of Kentish plover nests, will be flooded, if sea level rises by one metre. Our results are constrained by the availability of data on both elevation and bird populations. Therefore, we recommend follow-up studies to model the impacts of sea level rise using different elevation scenarios, and the establishment of a monitoring programme for breeding shorebirds and seabirds in Farasan Islands to assess the impact of climate change on their populations.

Sea-level records from the U.S. mid-Atlantic constrain Laurentide Ice Sheet extent during Marine Isotope Stage 3

PubMed Central

Pico, T; Creveling, J. R.; Mitrovica, J. X.

2017-01-01

The U.S. mid-Atlantic sea-level record is sensitive to the history of the Laurentide Ice Sheet as the coastline lies along the ice sheet's peripheral bulge. However, paleo sea-level markers on the present-day shoreline of Virginia and North Carolina dated to Marine Isotope Stage (MIS) 3, from 50 to 35 ka, are surprisingly high for this glacial interval, and remain unexplained by previous models of ice age adjustment or other local (for example, tectonic) effects. Here, we reconcile this sea-level record using a revised model of glacial isostatic adjustment characterized by a peak global mean sea level during MIS 3 of approximately −40 m, and far less ice volume within the eastern sector of the Laurentide Ice Sheet than traditional reconstructions for this interval. We conclude that the Laurentide Ice Sheet experienced a phase of very rapid growth in the 15 kyr leading into the Last Glacial Maximum, thus highlighting the potential of mid-field sea-level records to constrain areal extent of ice cover during glacial intervals with sparse geological observables. PMID:28555637

Return of the coral reef hypothesis - Basin to shelf partitioning of CaCO3 and its effect on atmospheric CO2

NASA Technical Reports Server (NTRS)

Opdyke, Bradley N.; Walker, James C. G.

1992-01-01

CaCO3 deposition rates in shallow water are assumed to vary in a sawtoothed manner about a long-term average deposition rate of 8 x 10 exp 12 mol/yr. It is proposed that rising sea level serves as the driving mechanism for changing the locus of CaCO3 deposition from deep sea to shallow shelf. Deposition on the shelves occurs when sea level is rising, while shelf carbonates dissolve when sea level is falling. It is shown that this mechanism alone can account for variations of atmospheric CO2 and can contribute to the pelagic carbonate dissolution cycles observed in the equatorial Pacific.

Heavy metals in fish from the Red Sea, Arabian Sea, and Indian Ocean: effect of origin, fish species and size and correlation among the metals.

PubMed

Obaidat, Mohammad M; Massadeh, Adnan M; Al-Athamneh, Ahmad M; Jaradat, Qasem M

2015-04-01

This study determined the levels of As, Cu, Pb, and Cd in fish from Red Sea, Arabian Sea, and Indian Ocean by graphite furnace atomic absorption spectrophotometry. Metal levels were compared with international standards. The levels among fish types and origin, the relationship among metals, and the correlation between the levels and fish size were statistically tested. Fish type and origin significantly affected the levels. None of the fish contained As, Cu, and Pb above the FAO and EU codes. However, Cd exceeded the Jordanian, FAO, and EC codes from the three origins. As and Cd positively correlated with each other in Arabian Sea fish. As and Pb correlated negatively, but Cu and Cd did not correlate with fish size. This study indicates that Cd is common in fish from the three origins regardless the fish size. This warrants continuous monitoring for heavy metals, especially Cd, in internationally traded fish.

Using Direct Policy Search to Identify Robust Strategies in Adapting to Uncertain Sea Level Rise and Storm Surge

NASA Astrophysics Data System (ADS)

Garner, G. G.; Keller, K.

2017-12-01

Sea-level rise poses considerable risks to coastal communities, ecosystems, and infrastructure. Decision makers are faced with deeply uncertain sea-level projections when designing a strategy for coastal adaptation. The traditional methods have provided tremendous insight into this decision problem, but are often silent on tradeoffs as well as the effects of tail-area events and of potential future learning. Here we reformulate a simple sea-level rise adaptation model to address these concerns. We show that Direct Policy Search yields improved solution quality, with respect to Pareto-dominance in the objectives, over the traditional approach under uncertain sea-level rise projections and storm surge. Additionally, the new formulation produces high quality solutions with less computational demands than the traditional approach. Our results illustrate the utility of multi-objective adaptive formulations for the example of coastal adaptation, the value of information provided by observations, and point to wider-ranging application in climate change adaptation decision problems.

A Bayesian network to predict vulnerability to sea-level rise: data report

USGS Publications Warehouse

Gutierrez, Benjamin T.; Plant, Nathaniel G.; Thieler, E. Robert

2011-01-01

During the 21st century, sea-level rise is projected to have a wide range of effects on coastal environments, development, and infrastructure. Consequently, there has been an increased focus on developing modeling or other analytical approaches to evaluate potential impacts to inform coastal management. This report provides the data that were used to develop and evaluate the performance of a Bayesian network designed to predict long-term shoreline change due to sea-level rise. The data include local rates of relative sea-level rise, wave height, tide range, geomorphic classification, coastal slope, and shoreline-change rate compiled as part of the U.S. Geological Survey Coastal Vulnerability Index for the U.S. Atlantic coast. In this project, the Bayesian network is used to define relationships among driving forces, geologic constraints, and coastal responses. Using this information, the Bayesian network is used to make probabilistic predictions of shoreline change in response to different future sea-level-rise scenarios.

Modeling Caspian Sea water level oscillations under different scenarios of increasing atmospheric carbon dioxide concentrations.

PubMed

Roshan, Gholamreza; Moghbel, Masumeh; Grab, Stefan

2012-12-12

The rapid rise of Caspian Sea water level (about 2.25 meters since 1978) has caused much concern to all five surrounding countries, primarily because flooding has destroyed or damaged buildings and other engineering structures, roads, beaches and farm lands in the coastal zone. Given that climate, and more specifically climate change, is a primary factor influencing oscillations in Caspian Sea water levels, the effect of different climate change scenarios on future Caspian Sea levels was simulated. Variations in environmental parameters such as temperature, precipitation, evaporation, atmospheric carbon dioxide and water level oscillations of the Caspian sea and surrounding regions, are considered for both past (1951-2006) and future (2025-2100) time frames. The output of the UKHADGEM general circulation model and five alternative scenarios including A1CAI, BIASF, BIMES WRE450 and WRE750 were extracted using the MAGICC SCENGEN Model software (version 5.3). The results suggest that the mean temperature of the Caspian Sea region (Bandar-E-Anzali monitoring site) has increased by ca. 0.17°C per decade under the impacts of atmospheric carbon dioxide changes (r=0.21). The Caspian Sea water level has increased by ca. +36cm per decade (r=0.82) between the years 1951-2006. Mean results from all modeled scenarios indicate that the temperature will increase by ca. 3.64°C and precipitation will decrease by ca. 10% (182 mm) over the Caspian Sea, whilst in the Volga river basin, temperatures are projected to increase by ca. 4.78°C and precipitation increase by ca. 12% (58 mm) by the year 2100. Finally, statistical modeling of the Caspian Sea water levels project future water level increases of between 86 cm and 163 cm by the years 2075 and 2100, respectively.

Modeling Caspian Sea water level oscillations under different scenarios of increasing atmospheric carbon dioxide concentrations

PubMed Central

2012-01-01

The rapid rise of Caspian Sea water level (about 2.25 meters since 1978) has caused much concern to all five surrounding countries, primarily because flooding has destroyed or damaged buildings and other engineering structures, roads, beaches and farm lands in the coastal zone. Given that climate, and more specifically climate change, is a primary factor influencing oscillations in Caspian Sea water levels, the effect of different climate change scenarios on future Caspian Sea levels was simulated. Variations in environmental parameters such as temperature, precipitation, evaporation, atmospheric carbon dioxide and water level oscillations of the Caspian sea and surrounding regions, are considered for both past (1951-2006) and future (2025-2100) time frames. The output of the UKHADGEM general circulation model and five alternative scenarios including A1CAI, BIASF, BIMES WRE450 and WRE750 were extracted using the MAGICC SCENGEN Model software (version 5.3). The results suggest that the mean temperature of the Caspian Sea region (Bandar-E-Anzali monitoring site) has increased by ca. 0.17°C per decade under the impacts of atmospheric carbon dioxide changes (r=0.21). The Caspian Sea water level has increased by ca. +36cm per decade (r=0.82) between the years 1951-2006. Mean results from all modeled scenarios indicate that the temperature will increase by ca. 3.64°C and precipitation will decrease by ca. 10% (182 mm) over the Caspian Sea, whilst in the Volga river basin, temperatures are projected to increase by ca. 4.78°C and precipitation increase by ca. 12% (58 mm) by the year 2100. Finally, statistical modeling of the Caspian Sea water levels project future water level increases of between 86 cm and 163 cm by the years 2075 and 2100, respectively. PMID:23369617

Sea Level Budget along the East Coast of North America

NASA Astrophysics Data System (ADS)

Pease, A. M.; Davis, J. L.; Vinogradova, N. T.

2016-12-01

We analyzed tide gauge data, taken from 1955 to 2015, from 29 locations along the east coast of North America. A well-documented period of sea-level acceleration began around 1990. The sea level rate (referenced to epoch 1985.0) and acceleration (post-1990) are spatially and temporally variable, due to various physical processes, each of which is also spatially and temporally variable. To determine the sea-level budgets for rate and acceleration, we considered a number of major contributors to sea level change: ocean density and dynamics, glacial isostatic adjustment (GIA), the inverted barometer effect, and mass change associated with the Greenland Ice Sheet (GIS) and the Antarctic Ice Sheet (AIS). The geographic variability in the budgets for sea-level rate is dominated by GIA. At some sites, GIA is the largest contributor to the rate. The geographic variability in the budgets for sea-level acceleration is dominated by ocean dynamics and density and GIS mass loss. The figure below shows budgets for sea-level rate (left) and acceleration (right) for Key West, Fla., (top) and The Battery in New York City (bottom). The blue represents values (with error bar shown) estimated from tide gauge observations, and the yellow represents the total values estimated from the individual model contributions (each in red, green, cyan, pink, and black). The estimated totals for rate and acceleration are good matches to the tide-gauge inferences. To achieve a reasonable fit, a scaling factor (admittance) for the combined contribution of ocean dynamics and density was estimated; this admittance may reflect the low spatial sampling of the GECCO2 model we used, or other problems in modeling coastal sea-level. The significant contributions of mass loss to the acceleration enable us to predict that, if such mass-loss continues or increases, the character of sea-level change on the North American east coast will change in the next 50-100 years. In particular, whereas GIA presently dominates the spatial variability of sea-level change, mass loss from Greenland and Antarctica will dominate it by 2050-2100. However, the long-term contribution of ocean dynamics and density remain more of a question.

GIS-based vulnerability assessment to sea level rise of Al Hoceima Bay (Moroccan Mediterranean): towards an integrated coastal zone management (ICZM)

NASA Astrophysics Data System (ADS)

Khouakhi, A.; Snoussi, M.

2013-12-01

In the context of coastal vulnerability to climate change and human impacts, integrated coastal zone management (ICZM) is an increasingly relevant process for the sustainable development of coastal areas, in which scientific input plays a vital role. In the Mediterranean Basin, projected increases in sea level rise and in the magnitude and frequency of extreme weather events pose a major challenge for the management of low-lying coastal ecosystems and human settlements. The bay of Al Hoceima is one of the least studied and largest low-lying coastal areas of the Moroccan Mediterranean coast, and is exposed to the effects of sea level rise and storms. The coast is also a touristic area and one of the most important economic assets in the region. Physical coastal vulnerability assessments, determination of setback lines, and evaluation of coastal aquifer vulnerability to sea level rise are among the principal tools used to help decision makers in such a context. Here we quantified, in the context of sea level rise: (1) the physical vulnerability of the coastline, by developing a standard index methodology based on the five most relevant physical indices for local-scale vulnerability analysis, for a total of 822 50m/50m coastal cells; (2) coastal setback lines, based on shoreline evolutionary trends adjusted to sea level rise scenarios using a digital shoreline Analysis System (DSAS); and (3) the vulnerability to sea water intrusion in the coastal aquifer, using a modified GALDIT index (ground water occurrence, aquifer hydraulic conductivity, depth to groundwater level above the sea; distance from the shore; impact of existing status of sea water intrusion in the area; and thickness of the aquifer), following an integrated GIS approach. We find that 41% of the studied coastline is highly vulnerable to the effects of sea level rise and extreme weather events; 60% of the coastline is in retreat (with rates varying between -2m and -0.2m/y), 30% is in dynamic equilibrium (rates of -0.2 to +0.2m/y), and 10% is gradually prograding (with accretion rates of +0.2 to +0.8m/y). Setback line analysis indicates a potential retreat of the coastline of up to -90m by 2050 in the most vulnerable sectors. We find that the aquifer is subject to a moderate to high risk for at least half of its total area, and that for an assumed sea level rise of 0.5 m, the vulnerable surface area will increase by up to two times. The assessment of coastal erosion under different scenarios of sea level rise showed that, if no action is taken, most of the beaches are likely to disappear from the coupled effects of erosion and inundation. These findings will have direct repercussions for coastal development programs over both the short and long terms. The final results aim to provide coastal managers with tools to help the implementation of ICZM.

Projecting future sea level

USGS Publications Warehouse

Cayan, Daniel R.; Bromirski, Peter; Hayhoe, Katharine; Tyree, Mary; Dettinger, Mike; Flick, Reinhard

2006-01-01

California’s coastal observations and global model projections indicate that California’s open coast and estuaries will experience increasing sea levels over the next century. Sea level rise has affected much of the coast of California, including the Southern California coast, the Central California open coast, and the San Francisco Bay and upper estuary. These trends, quantified from a small set of California tide gages, have ranged from 10–20 centimeters (cm) (3.9–7.9 inches) per century, quite similar to that estimated for global mean sea level. So far, there is little evidence that the rate of rise has accelerated, and the rate of rise at California tide gages has actually flattened since 1980, but projections suggest substantial sea level rise may occur over the next century. Climate change simulations project a substantial rate of global sea level rise over the next century due to thermal expansion as the oceans warm and runoff from melting land-based snow and ice accelerates. Sea level rise projected from the models increases with the amount of warming. Relative to sea levels in 2000, by the 2070–2099 period, sea level rise projections range from 11–54 cm (4.3–21 in) for simulations following the lower (B1) greenhouse gas (GHG) emissions scenario, from 14–61 cm (5.5–24 in) for the middle-upper (A2) emission scenario, and from 17–72 cm (6.7–28 in) for the highest (A1fi) scenario. In addition to relatively steady secular trends, sea levels along the California coast undergo shorter period variability above or below predicted tide levels and changes associated with long-term trends. These variations are caused by weather events and by seasonal to decadal climate fluctuations over the Pacific Ocean that in turn affect the Pacific coast. Highest coastal sea levels have occurred when winter storms and Pacific climate disturbances, such as El Niño, have coincided with high astronomical tides. This study considers a range of projected future global sea level rises in examining possible impacts at California coastal and estuarine stations. Two climate models and three scenarios considered in this scenarios study provide a set of possible future weather and short-period climate fluctuations, and a range of potential long-term sea level rise values. A range of mean sea level rise was considered in combination with weather and El Niño fluctuations extracted from two global climate models and two GHG emissions scenarios. The mean sea level rise values, determined from a survey of several climate models, range from approximately 10–80 cm (3.9–31 in) between 2000 and 2100. The middle to higher end of this range would substantially exceed the historical rate of sea level rise of 15–20 cm (5.9–7.9 in)per century observed at San Francisco and San Diego during the last 100 years. Gradual sea level rise progressively worsens the impacts of high tides and the surge and waves associated with storms. The potential for impacts of future sea level rise was assessed from the occurrence of hourly sea level extremes. The occurrence of extreme events follows a sharply escalating pattern as the magnitude of future sea level rise increases. The confluence of Low barometric pressures from storms and the presence large waves at the same time substantially increases the likelihood of high, damaging sea levels along the California coast. Similarly, astronomical tides and disturbances in sea level that are caused by weather and climate fluctuations are x transmitted into the San Francisco Bay and Delta, and on into the lower reaches of the Sacramento River. In addition to elevating Bay and Delta sea levels directly through inverse barometer and wind effects, storms may generate heavy precipitation and high fresh water runoff and cause floods in the Sacramento/San Joaquin Delta, increasing the potential for inundation of levees and other structures. There may also be increased risk of levee failure due to the hydraulics and geometry of these structures. Rising sea levels from climate change will increase the frequency and duration of extreme high water levels, causing historical coastal and San Francisco Bay/Delta structure design criteria to be exceeded.

Potential effects of sea-level rise on the depth to saturated sediments of the Sagamore and Monomoy flow lenses on Cape Cod, Massachusetts

USGS Publications Warehouse

Walter, Donald A.; McCobb, Timothy D.; Masterson, John P.; Fienen, Michael N.

2016-05-25

In 2014, the U.S. Geological Survey, in cooperation with the Association to Preserve Cape Cod, the Cape Cod Commission, and the Massachusetts Environmental Trust, began an evaluation of the potential effects of sea-level rise on water table altitudes and depths to water on central and western Cape Cod, Massachusetts. Increases in atmospheric and oceanic temperatures arising, in part, from the release of greenhouse gases likely will result in higher sea levels globally. Increasing water table altitudes in shallow, unconfined coastal aquifer systems could adversely affect infrastructure—roads, utilities, basements, and septic systems—particularly in low-lying urbanized areas. The Sagamore and Monomoy flow lenses on Cape Cod are the largest and most populous of the six flow lenses that comprise the region’s aquifer system, the Cape Cod glacial aquifer. The potential effects of sea-level rise on water table altitude and depths to water were evaluated by use of numerical models of the region. The Sagamore and Monomoy flow lenses have a number of large surface water drainages that receive a substantial amount of groundwater discharge, 47 and 29 percent of the total, respectively. The median increase in the simulated water table altitude following a 6-foot sea-level rise across both flow lenses was 2.11 feet, or 35 percent when expressed as a percentage of the total sea-level rise. The response is nearly the same as the sea-level rise (6 feet) in some coastal areas and less than 0.1 foot near some large inland streams. Median water table responses differ substantially between the Sagamore and Monomoy flow lenses—at 29 and 49 percent, respectively—because larger surface water discharge on the Sagamore flow lens results in increased dampening of the water table response than in the Monomoy flow lens. Surface waters dampen water table altitude increases because streams are fixed-altitude boundaries that cause hydraulic gradients and streamflow to increase as sea-level rises, partially fixing the local water table altitude.The region has a generally thick vadose zone with a mean of about 38 feet; areas with depths to water of 5 feet or less, as estimated from light detection and ranging (lidar) data from 2011 and simulated water table altitudes, currently [2011] occur over about 24.9 square miles, or about 8.4 percent of the total land area of the Sagamore and Monomoy flow lenses, generally in low-lying coastal areas and inland near ponds and streams. Excluding potentially submerged areas, an additional 4.5, 9.8, and 15.9 square miles would have shallow depths to water (5 feet or less) for projected sea-level rises of 2, 4, and 6 feet above levels in 2011. The additional areas with shallow depths to water generally occur in the same areas as the areas with current [2011] depths to water of 5 feet or less: low-lying coastal areas and near inland surface water features. Additional areas with shallow depths to water for the largest sea-level rise prediction (6 feet) account for about 5.7 percent of the total land area, excluding areas likely to be inundated by seawater. The numerous surface water drainages will dampen the response of the water table to sea-level rise. This dampening, combined with the region’s thick vadose zone, likely will mitigate the potential for groundwater inundation in most areas. The potential does exist for groundwater inundation in some areas, but the effects of sea-level rise on depths to water and infrastructure likely will not be substantial on a regional level.

Contrasting population histories of the deep-sea demersal fish, Lycodes matsubarai, in the Sea of Japan and the Sea of Okhotsk.

PubMed

Sakuma, Kay; Ueda, Yuji; Hamatsu, Tomonori; Kojima, Shigeaki

2014-06-01

Recent studies have revealed the impact of the drastic climate change during the last glacial period on coastal marine and anadromous species in the marginal seas of the northwestern Pacific Ocean; however, its influence on deep-sea species remains poorly understood. To compare the effects of the last glacial period on populations from the Sea of Japan and the Sea of Okhotsk, we examined the mitochondrial control region and cytochrome b gene sequences of Lycodes matsubarai, a deepsea demersal fish that inhabits these two seas. Our results showed clear genetic differentiation of populations between the two seas. The populations may have diverged during the last glacial period, probably as a result of vicariance due to the drastic sea level change. The population in the Sea of Okhotsk was larger than that in the Sea of Japan, but suddenly decreased after the last glacial period. However, the Sea of Japan population expanded after the last glacial period, coincident with high levels of oxygenation in deep-sea areas. These results elucidate regional-scale impacts of climate change on deep-sea organisms.

Sea-level variability over the Common Era

NASA Astrophysics Data System (ADS)

Kopp, Robert; Horton, Benjamin; Kemp, Andrew; Engelhart, Simon; Little, Chris

2017-04-01

The Common Era (CE) sea-level response to climate forcing, and its relationship to centennial-timescale climate variability such as the Medieval Climate Anomaly (MCA) and the Little Ice Age (LIA), is fragmentary relative to other proxy-derived climate records (e.g. atmospheric surface temperature). However, the Atlantic coast of North America provides a rich sedimentary record of CE relative sea level with sufficient spatial and temporal resolution to inform mechanisms underlying regional and global sea level variability and their relationship to other climate proxies. This coast has a small tidal range, improving the precision of sea-level reconstructions. Coastal subsidence (from glacial isostatic adjustment, GIA) creates accommodation space that is filled by salt-marsh peat and preserves accurate and precise sea-level indicators and abundant material for radiocarbon dating. In addition to longer term GIA induced land-level change from ongoing collapse of the Laurentide forebulge, these records are ideally situated to capture climate-driven sea level changes. The western North Atlantic Ocean sea level is sensitive to static equilibrium effects from melting of the Greenland Ice Sheet, as well as large-scale changes in ocean circulation and winds. Our reconstructions reveal two distinct patterns in sea-level during the CE along the United States Atlantic coast: (1) South of Cape Hatteras, North Carolina, to Florida sea-level rise is essentially flat, with the record dominated by long-term geological processes until the onset of historic rates of rise in the late 19th century; (2) North of Cape Hatteras to Connecticut, sea level rise to maximum around 1000CE, a sea-level minimum around 1500 CE, and a long-term sea-level rise through the second half of the second millennium. The northern-intensified sea-level fall beginning 1000 is coincident with shifts toward persistent positive NAO-like atmospheric states inferred from other proxy records and is consistent with climate model simulations forced with sustained NAO-like heat fluxes. Changes in the wind-driven ocean circulation may also contribute to alongshore sea level variability over the CE. To reveal global mean sea level variability, we combine the salt-marsh data from North American Atlantic coast with tide-gauge records and other high resolution proxies from the northern and southern hemispheres. All reconstructions are from coasts that are tectonically stable and are based on four types of proxy archives (archaeological indicators, coral microatolls, salt marsh sediments and vermetid [mollusk] bioconstructions) that are best capable of capturing submeter-scale RSL changes. The database consists of reconstructions from Australasia (n = 2), Europe (n=5), Greenland (n = 3), North America (n = 6), the northern Gulf of Mexico (n = 3), the Mediterranean (n = 1), South Africa (n = 2), South America (n =2) and the South Pacific (n =3). We apply a noisy-input Gaussian process spatio-temporal modeling framework, which identifies a long-term falling global mean sea-level, interrupted in the middle of the 19th century by an acceleration yielding a 20th century rate of rise extremely likely (probability P = 0:95) faster than any previous century in the CE.

Relative and Geocentric Sea Level Rise Along the U.S. West Coast

NASA Astrophysics Data System (ADS)

Burgette, R. J.; Watson, C. S.

2015-12-01

The rate of sea level change relative to the land along the West Coast of the U.S. varies over a range of +5 to -2 mm/yr, as observed across the set of long-running tide gauges. We analyze tide gauge data in a network approach that accounts for temporal and spatial correlations in the time series of water levels observed at the stations. This analysis yields a set of rate estimates and realistic uncertainties that are minimally affected by varying durations of observations. The analysis has the greatest impact for tide gauges with short records, as the adjusted rate uncertainties for 2 to 3 decade duration tide gauges approach those estimated from unadjusted century-scale time series. We explore the sources of the wide range of observed relative sea level rates through comparison with: 1) estimated vertical deformation rates derived from repeated leveling and GPS, 2) relative sea level change predicted from models of glacial isostatic adjustment, and 3) geocentric sea level rates estimated from satellite altimetry and century-scale reconstructions. Tectonic deformation is the dominant signal in the relative sea level rates along the Cascadia portion of the coast, and is consistent with along-strike variation in locking behavior on the plate interface. Rates of vertical motion are lower along the transform portion of the plate boundary and include anthropogenic effects, but there are significant tectonic signals, particularly in the western Transverse Ranges of California where the crust is shortening across reverse faults. Preliminary analysis of different strategies of estimating the magnitude of geocentric sea level rise suggest significant discrepancies between approaches. We will examine the implications of these discrepancies for understanding the process of regional geocentric sea level rise in the northeastern Pacific Ocean, and associated projected impacts.

A simple model to estimate the impact of sea-level rise on platform beaches

NASA Astrophysics Data System (ADS)

Taborda, Rui; Ribeiro, Mónica Afonso

2015-04-01

Estimates of future beach evolution in response to sea-level rise are needed to assess coastal vulnerability. A research gap is identified in providing adequate predictive methods to use for platform beaches. This work describes a simple model to evaluate the effects of sea-level rise on platform beaches that relies on the conservation of beach sand volume and assumes an invariant beach profile shape. In closed systems, when compared with the Inundation Model, results show larger retreats; the differences are higher for beaches with wide berms and when the shore platform develops at shallow depths. The application of the proposed model to Cascais (Portugal) beaches, using 21st century sea-level rise scenarios, shows that there will be a significant reduction in beach width.

Climate change and Sea level rise: Potential impact on the coast of the Edremit Plain, NW Turkey.

NASA Astrophysics Data System (ADS)

Curebal, Isa; Efe, Recep; Soykan, Abdullah; Sonmez, Suleyman

2015-04-01

Over the past century, most of the world's mountain glaciers and the ice sheets have lost mass due to global warming. When the temperature exceeds a particular level, glaciers and polar ice caps will continue to lose mass. Recent studies report that low-lying coastal areas will be seriously affected by sea level rise. Changes in the amount of natural and anthropogenic greenhouse gases and aerosols had a warming effect on the global climate during last century. Thus, the pace of melting of ice sheets increased, and, accordingly, sea level began to rise faster. Rise in sea level between 1961 and 2003 was equal to 1.8 mm/year while it was 3.1 mm/year between 1993 and 2003. The total rise in the 20th century is estimated to be between 17 and 19 cm. The models based on the sea level change indicate that the average global temperature at the end of the 21st century will increase by 0.3°C - 6.4°C. Global sea level is projected to rise 8-25 cm by 2030, relative to 2000 levels, 18-48 cm by 2050, and 50-140 cm by 20110. The Edremit Plain lies between Mount Madra and the Kaz Mountains on the coast of Aegean Sea in NW Turkey. It is lowland with an area of 141 km2. The widest part of the plain is 16 km along the E - W direction. The N - S direction amounts to a width of 15 km. The plain is covered with alluvial deposits that settled in the Quaternary Period. The elevation ranges from 0 to 50 m a.s.l. in the plain. This study aims to determine how the low-lying coastal land areas of the Edremit Plain may be affected by possible changes in sea level. Elevation dataset is based on the digital elevation model (DEM) of Landsat ETM + satellite images. To that end, satellite images were used to draw the current coastline. Curves of 2.5, 5, and 10 m were drawn through the use of maps with a scale of 1/25.000. Later on, the areas of the fields between these points were calculated. Current estimates show that 2.5 m rise in sea level will cause sea water to cover an area of 8.6 km2 (%14.0), 5 m to 28.4 km2 (%21.2), and 10 m to 58.3 km2 (%41.2) on the coastal land. In such cases, a +2.5 m change will trigger the current coastline to regress by 1.3 km while a +5 m change will lead to 3.4 km, and a +10 m change will cause 5.2 km. As a result, residential, agricultural, and wetlands on the coastal land of the plain will be submerged by rising sea levels, leading to significant habitat loss and changes in the ecosystem. The creation of detailed elevation may reveal more clear effects of the changes in sea level. Key Words: Climate change, coastline, Edremit plain, global warming, sea level rise.

Protective Effect of Proanthocyanidins from Sea Buckthorn (Hippophae Rhamnoides L.) Seed against Visible Light-Induced Retinal Degeneration in Vivo.

PubMed

Wang, Yong; Zhao, Liang; Huo, Yazhen; Zhou, Feng; Wu, Wei; Lu, Feng; Yang, Xue; Guo, Xiaoxuan; Chen, Peng; Deng, Qianchun; Ji, Baoping

2016-05-02

Dietary proanthocyanidins (PACs) as health-protective agents have become an important area of human nutrition research because of their potent bioactivities. We investigated the retinoprotective effects of PACs from sea buckthorn (Hippophae rhamnoides L.) seed against visible light-induced retinal degeneration in vivo. Pigmented rabbits were orally administered sea buckthorn seed PACs (50 and 100 mg/kg/day) for 14 consecutive days of pre-illumination and seven consecutive days of post-illumination. Retinal function was quantified via electroretinography 7 days after light exposure. Retinal damage was evaluated by measuring the thickness of the full-thickness retina and outer nuclear layer 7 days after light exposure. Sea buckthorn seed PACs significantly attenuated the destruction of electroretinograms and maintained the retinal structure. Increased retinal photooxidative damage was expressed by the depletion of glutathione peroxidase and catalase activities, the decrease of total antioxidant capacity level and the increase of malondialdehyde level. Light exposure induced a significant increase of inflammatory cytokines (IL-1β, TNF-α and IL-6) and angiogenesis (VEGF) levels in retina. Light exposure upregulated the expression of pro-apoptotic proteins Bax and caspase-3 and downregulated the expression of anti-apoptotic protein Bcl-2. However, sea buckthorn seed PACs ameliorated these changes induced by light exposure. Sea buckthorn seed PACs mediated the protective effect against light-induced retinal degeneration via antioxidant, anti-inflammatory and antiapoptotic mechanisms.

Protective Effect of Proanthocyanidins from Sea Buckthorn (Hippophae Rhamnoides L.) Seed against Visible Light-Induced Retinal Degeneration in Vivo

PubMed Central

Wang, Yong; Zhao, Liang; Huo, Yazhen; Zhou, Feng; Wu, Wei; Lu, Feng; Yang, Xue; Guo, Xiaoxuan; Chen, Peng; Deng, Qianchun; Ji, Baoping

2016-01-01

Dietary proanthocyanidins (PACs) as health-protective agents have become an important area of human nutrition research because of their potent bioactivities. We investigated the retinoprotective effects of PACs from sea buckthorn (Hippophae rhamnoides L.) seed against visible light-induced retinal degeneration in vivo. Pigmented rabbits were orally administered sea buckthorn seed PACs (50 and 100 mg/kg/day) for 14 consecutive days of pre-illumination and seven consecutive days of post-illumination. Retinal function was quantified via electroretinography 7 days after light exposure. Retinal damage was evaluated by measuring the thickness of the full-thickness retina and outer nuclear layer 7 days after light exposure. Sea buckthorn seed PACs significantly attenuated the destruction of electroretinograms and maintained the retinal structure. Increased retinal photooxidative damage was expressed by the depletion of glutathione peroxidase and catalase activities, the decrease of total antioxidant capacity level and the increase of malondialdehyde level. Light exposure induced a significant increase of inflammatory cytokines (IL-1β, TNF-α and IL-6) and angiogenesis (VEGF) levels in retina. Light exposure upregulated the expression of pro-apoptotic proteins Bax and caspase-3 and downregulated the expression of anti-apoptotic protein Bcl-2. However, sea buckthorn seed PACs ameliorated these changes induced by light exposure. Sea buckthorn seed PACs mediated the protective effect against light-induced retinal degeneration via antioxidant, anti-inflammatory and antiapoptotic mechanisms. PMID:27144578

Seismicity and strain transients in the Gulf of Corinth (Greece)

NASA Astrophysics Data System (ADS)

Canitano, A.; Bernard, P.; Linde, A. T.; Sacks, S. I.; Boudin, F.

2009-12-01

The Gulf of Corinth (Greece) is one of the most seismic regions in Europe, producing some earthquakes of magnitude greater than 5.8 in the last 35 years, 1 to 1.5 cm/yr of north-south extension, and frequent seismic swarms. This structure is a 110 km long, N110°E oriented graben bounded by systems of very recent normal faults. This zone thus provides an ideal site for investigating in situ the physics of earthquake sources and for developing efficient seismic hazard reduction procedures. The Corinth Rift Laboratory (CRL) project is concentrated in the western part of the rift, around the city of Aigion, where instrumental seismicity and strain rate is highest. The CRL Network is made up about fifteen seismic stations as well as tiltmeters, strainmeters or GPS in order to study the local seismicity, and to observe and model the short and long term mechanics of the normal fault system. The instrumental seismicity in the Aigion zone clearly shows a strong concentration of small earthquakes between 5 and 10 km. In order to study slow transient deformation, two borehole strainmeters have been installed in the Gulf (Trizonia, Monasteraki). The strainmeter installed in the Trizonia island is continuously recording the horizontal strain at 150m depth with a resolution better than 10-9. The dominant signal is the earth and sea tidal effects (few 10-7 strain), this one is modulated by the mechanical effects of the free oscillations of the Gulf with periods between 8 and 40 min. The barometric pressure fluctuations acts in combination with the mean sea level variation at longer periods and both effects are not independant. The comparison between the strain data and the two forcing signals (sea-level, barometric pressure) shows clearly a non zero phase delay of the sea-level. The analysis of time correlations between the signals in differents frequency range exhibits that the sea level delay and the strainmeter/sea-level coupling coefficient are increasing with period (about 1/10 of a period for 10-40 hrs period range). This analysis allows us to estimate a transfert function for each forcing signal but the physical interpretation of the sea-level function is still unclear. As the strainmeter is at 150m depth, below the shoreline, a sea water percolation on land would increase the effect of sea level fluctuation, and be more efficient at longer periods. This interpretation allow us to study accurately this external perturbations and to remove them from the strain signal. The residual signal is 8 times smaller than the original strain signal for 10mn-1hr period (RMS=0,27.10-9 strain and no sea-level signal delay) and 4 times for 30-40hr (RMS=0,63.10-9 strain). This residual signals are studied in order to find slow transient signatures, especially during the reported seismic swarms.

Changes in size and trends of North American sea duck populations associated with North Pacific oceanic regime shifts

USGS Publications Warehouse

Flint, Paul L.

2013-01-01

Broad-scale multi-species declines in populations of North American sea ducks for unknown reasons is cause for management concern. Oceanic regime shifts have been associated with rapid changes in ecosystem structure of the North Pacific and Bering Sea. However, relatively little is known about potential effects of these changes in oceanic conditions on marine bird populations at broad scales. I examined changes in North American breeding populations of sea ducks from 1957 to 2011 in relation to potential oceanic regime shifts in the North Pacific in 1977, 1989, and 1998. There was strong support for population-level effects of regime shifts in 1977 and 1989, but little support for an effect of the 1998 shift. The continental-level effects of these regime shifts differed across species groups and time. Based on patterns of sea duck population dynamics associated with regime shifts, it is unclear if the mechanism of change relates to survival or reproduction. Results of this analysis support the hypothesis that population size and trends of North American sea ducks are strongly influenced by oceanic conditions. The perceived population declines appear to have halted >20 years ago, and populations have been relatively stable or increasing since that time. Given these results, we should reasonably expect dramatic changes in sea duck population status and trends with future oceanic regime shifts.

A new phase in the production of quality-controlled sea level data

NASA Astrophysics Data System (ADS)

Quartly, Graham D.; Legeais, Jean-François; Ablain, Michaël; Zawadzki, Lionel; Joana Fernandes, M.; Rudenko, Sergei; Carrère, Loren; Nilo García, Pablo; Cipollini, Paolo; Andersen, Ole B.; Poisson, Jean-Christophe; Mbajon Njiche, Sabrina; Cazenave, Anny; Benveniste, Jérôme

2017-08-01

Sea level is an essential climate variable (ECV) that has a direct effect on many people through inundations of coastal areas, and it is also a clear indicator of climate changes due to external forcing factors and internal climate variability. Regional patterns of sea level change inform us on ocean circulation variations in response to natural climate modes such as El Niño and the Pacific Decadal Oscillation, and anthropogenic forcing. Comparing numerical climate models to a consistent set of observations enables us to assess the performance of these models and help us to understand and predict these phenomena, and thereby alleviate some of the environmental conditions associated with them. All such studies rely on the existence of long-term consistent high-accuracy datasets of sea level. The Climate Change Initiative (CCI) of the European Space Agency was established in 2010 to provide improved time series of some ECVs, including sea level, with the purpose of providing such data openly to all to enable the widest possible utilisation of such data. Now in its second phase, the Sea Level CCI project (SL_cci) merges data from nine different altimeter missions in a clear, consistent and well-documented manner, selecting the most appropriate satellite orbits and geophysical corrections in order to further reduce the error budget. This paper summarises the corrections required, the provenance of corrections and the evaluation of options that have been adopted for the recently released v2.0 dataset (https://doi.org/10.5270/esa-sea_level_cci-1993_2015-v_2.0-201612). This information enables scientists and other users to clearly understand which corrections have been applied and their effects on the sea level dataset. The overall result of these changes is that the rate of rise of global mean sea level (GMSL) still equates to ˜ 3.2 mm yr-1 during 1992-2015, but there is now greater confidence in this result as the errors associated with several of the corrections have been reduced. Compared with v1.1 of the SL_cci dataset, the new rate of change is 0.2 mm yr-1 less during 1993 to 2001 and 0.2 mm yr-1 higher during 2002 to 2014. Application of new correction models brought a reduction of altimeter crossover variances for most corrections.

Sea-level rise impacts on the tides of the European Shelf

NASA Astrophysics Data System (ADS)

Idier, Déborah; Paris, François; Cozannet, Gonéri Le; Boulahya, Faiza; Dumas, Franck

2017-04-01

Sea-level rise (SLR) can modify not only total water levels, but also tidal dynamics. Several studies have investigated the effects of SLR on the tides of the western European continental shelf (mainly the M2 component). We further investigate this issue using a modelling-based approach, considering uniform SLR scenarios from -0.25 m to +10 m above present-day sea level. Assuming that coastal defenses are constructed along present-day shorelines, the patterns of change in high tide levels (annual maximum water level) are spatially similar, regardless of the magnitude of sea-level rise (i.e., the sign of the change remains the same, regardless of the SLR scenario) over most of the area (70%). Notable increases in high tide levels occur especially in the northern Irish Sea, the southern part of the North Sea and the German Bight, and decreases occur mainly in the western English Channel. These changes are generally proportional to SLR, as long as SLR remains smaller than 2 m. Depending on the location, they can account for +/-15% of regional SLR. High tide levels and the M2 component exhibit slightly different patterns. Analysis of the 12 largest tidal components highlights the need to take into account at least the M2, S2, N2, M4, MS4 and MN4 components when investigating the effects of SLR on tides. Changes in high tide levels are much less proportional to SLR when flooding is allowed, in particular in the German Bight. However, some areas (e.g., the English Channel) are not very sensitive to this option, meaning that the effects of SLR would be predictable in these areas, even if future coastal defense strategies are ignored. Physically, SLR-induced tidal changes result from the competition between reductions in bed friction damping, changes in resonance properties and increased reflection at the coast, i.e., local and non-local processes. A preliminary estimate of tidal changes by 2100 under a plausible non-uniform SLR scenario (using the RCP4.5 scenario) is provided. Though the changes display similar patterns, the high water levels appear to be sensitive to the non-uniformity of SLR.

Sea breezes and advective effects in southwest James Bay

NASA Technical Reports Server (NTRS)

Mckendry, Ian; Roulet, Nigel

1994-01-01

Observations from a transect extending 100 km inland during the Northern Wetlands Study (NOWES) in 1990 show that the sea breeze develops on approximately 25% of days during summer and may penetrate up to 100 km inland on occasions. The sea breeze exhibits a marked diurnal clockwise rotation as a result of the Coriolis effect along the unobstructed coastline. The marine advective effect is shown to depend on gradient wind direction. With northwesterly upper level flow the sea breeze tends to be northeasterly in direction and is associated with decreased temperatures and vapor pressure deficits (VPD). With southwesterly upper level flow the sea breeze tends to have a southeasterly direction and less effect on temperatures and VPD. This is attributed to shorter residence times of air parcels over water. For two cases, Colorado State University mesoscale model simulations show good agreement with surface wind observations and suggest that under northwesterly gradient flow, Bowen ratios are increased in the onshore flow along western James Bay, while during southwesterly gradient flow these effects are negligible. These results have implications for the interpretation of local climate, ecology, and hydrology as well as land-based and airborne turbulent flux measurements made during NOWES.

75 FR 31368 - Proposed Flood Elevation Determinations

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-03

... referenced ground [caret] Communities affected elevation Elevation in meters (MSL) Effective Modified Santa.... Depth in feet above ground. [caret] Mean Sea Level, rounded to the nearest 0.1 meter. ** BFEs to be... Vertical Datum. Depth in feet above ground. [caret] Mean Sea Level, rounded to the nearest 0.1 meter...

Potential sea-level rise impacts on tidal wetlands in the Pacific Northwest: Declines in productivity and diversity?

EPA Science Inventory

Global climate change could alter sea-level and salinity dynamics in Pacific Northwest estuaries. We combined survey and experimental approaches to better understand potential climate change effects on the future of tidal wetland primary producers in the region. Surveys conducte...

The Response of Spartina Alterniflora to Multiple Stressors of Eutrophication, Precipitation Changes, and Sea Level Rise

EPA Science Inventory

A four month experiment using greenhouse mesocosms was conducted to analyze the effects of eutrophication, sea level rise, and precipitation changes on the salt marsh plant Spartina alterniflora. Pots containing plants were placed in six 600L tanks that received seawater pumped f...

Plant growth under salinity and inundation stress: implications for sea-level rise on tidal wetland function

EPA Science Inventory

Climate change and sea-level rise (SLR) may increase salinity or inundation duration for tidal wetland organisms. To test the effects of these stressors on wetland productivity, we transplanted seedlings of seven common plant species to polyhaline, mesohaline and oligohaline tida...

Fully reprocessed ERS-1 altimeter data from 1992 to 1995: Feasibility of the detection of long term sea level change

NASA Astrophysics Data System (ADS)

Anzenhofer, M.; Gruber, T.

1998-04-01

Global mean sea level observations are necessary to answer the urgent questions about climate changes and their impact on socio-economy. At GeoForschungsZentrum/Geman Processing and Archiving Facility ERS altimeter data is used to systematically generate geophysical products such as sea surface topography, high-resolution geoid and short- and long-period sea surface height models. On the basis of this experience, fully reprocessed ERS-1 altimeter data is used to generated a time series of monthly sea surface height models from April 1992 to April 1995. The reprocessing consists of improved satellite ephemerides, merging of Grenoble tidal model, and application of range corrections due to timing errors. With the new data set the TOPEX/POSEIDON prelaunch accuracy requirements are fulfilled. The 3-year time series is taken to estimate the rate of change of global mean sea level. A careful treatment of seasonal effects is considered. A masking of continents, sea ice, and suspect sea surface heights is chosen that is common for all sea surface height models. The obtained rate of change is compared to external results from tide gauge records and TOPEX/POSEIDON data. The relation of sea level changes and sea surface temperature variations is examined by means of global monthly sea surface temperature maps. Both global wind speed and wave height maps are investigated and correlated with sea surface heights and sea surface temperatures in order to find other indicators of climate variations. The obtained rate of changes of the various global maps is compared to an atmospheric CO2 anomaly record, which is highly correlated to El Niño events. The relatively short period of 3 years, however, does not allow definite conclusions with respect to possible long-term climate changes.

Trends and interannual variability of mass and steric sea level in the Tropical Asian Seas

NASA Astrophysics Data System (ADS)

Kleinherenbrink, Marcel; Riva, Riccardo; Frederikse, Thomas; Merrifield, Mark; Wada, Yoshihide

2017-08-01

The mass and steric components of sea level changes have been separated in the Tropical Asian Seas (TAS) using a statistically optimal combination of Jason satellite altimetry, GRACE satellite gravimetry, and ocean reanalyses. Using observational uncertainties, statistically optimally weighted time series for both components have been obtained in four regions within the TAS over the period January 2005 to December 2012. The mass and steric sea level variability is regressed with the first two principal components (PC1&2) of Pacific equatorial wind stress and the Dipole Mode Index (DMI). Sea level in the South China Sea is not affected by any of the indices. Steric variability in the TAS is largest in the deep Banda and Celebes seas and is affected by both PCs and the DMI. Mass variability is largest on the continental shelves, which is primarily controlled by PC1. We argue that a water flux from the Western Tropical Pacific Ocean is the cause for mass variability in the TAS. The steric trends are about 2 mm yr-1 larger than the mass trends in the TAS. A significant part of the mass trend can be explained by the aforementioned indices and the nodal cycle. Trends obtained from fingerprints of mass redistribution are statistically equal to mass trends after subtracting the nodal cycle and the indices. Ultimately, the effect of omitting the TAS in global sea level budgets is estimated to be 0.3 mm yr-1.

Sea level variation

NASA Technical Reports Server (NTRS)

Douglas, Bruce C.

1992-01-01

Published values for the long-term, global mean sea level rise determined from tide gauge records range from about one to three mm per year. The scatter of the estimates appears to arise largely from the use of data from gauges located at convergent tectonic plate boundaries where changes of land elevation give fictitious sea level trends, and the effects of large interdecadal and longer sea level variations on short (less than 50+ years) or sappy records. In addition, virtually all gauges undergo subsidence or uplift due to isostatic rebound from the last deglaciation at a rate comparable to or greater than the secular rise of sea level. Modeling rebound by the ICE-3G model of Tushingham and Peltier (1990) and avoiding tide gauge records in areas of converging tectonic plates produces a highly consistent set of long sea level records. A global set of 21 such stations in nine oceanic regions with an average record length of 76 years during the period 1880-1980 yields the global sea level rise value 1.8 mm/year +/- 0.1. Greenhouse warming scenarios commonly forecast an additional acceleration of global sea level in the next 5 or 6+ decades in the range 0.1-0.2 mm/yr2. Because of the large power at low frequencies in the sea level spectrum, very long tide gauge records (75 years minimum) have been examined for past apparent sea level acceleration. For the 80-year period 1905-1985, 23 essentially complete tide gauge records in 10 geographic groups are available for analysis. These yielded the apparent global acceleration -0.011 (+/- 0.012) mm/yr2. A larger, less uniform set of 37 records in the same 10 groups with 92 years average length covering the 141 years from 1850-1991 gave 0.001 (+/- 0.008) mm/yr2. Thus there is no evidence for an apparent acceleration in the past 100+ years that is significant either statistically, or in comparison to values associated with global warming. Unfortunately, the large interdecadal fluctuations of sea level severely affect estimates of global sea level acceleration for time spans of less than about 50 years. This means that tide gauges alone cannot serve as a reliable leading indicator of climate change in less than many decades. This time required can be significantly reduced if the interdecadal fluctuations of sea level can be understood in terms of their forcing mechanisms, and then removed from the tide gauge records.

Sea level, paleogeography, and archeology on California's Northern Channel Islands

NASA Astrophysics Data System (ADS)

Reeder-Myers, Leslie; Erlandson, Jon M.; Muhs, Daniel R.; Rick, Torben C.

2015-03-01

Sea-level rise during the late Pleistocene and early Holocene inundated nearshore areas in many parts of the world, producing drastic changes in local ecosystems and obscuring significant portions of the archeological record. Although global forces are at play, the effects of sea-level rise are highly localized due to variability in glacial isostatic adjustment (GIA) effects. Interpretations of coastal paleoecology and archeology require reliable estimates of ancient shorelines that account for GIA effects. Here we build on previous models for California's Northern Channel Islands, producing more accurate late Pleistocene and Holocene paleogeographic reconstructions adjusted for regional GIA variability. This region has contributed significantly to our understanding of early New World coastal foragers. Sea level that was about 80-85 m lower than present at the time of the first known human occupation brought about a landscape and ecology substantially different than today. During the late Pleistocene, large tracts of coastal lowlands were exposed, while a colder, wetter climate and fluctuating marine conditions interacted with rapidly evolving littoral environments. At the close of the Pleistocene and start of the Holocene, people in coastal California faced shrinking land, intertidal, and subtidal zones, with important implications for resource availability and distribution.

Sea level, paleogeography, and archeology on California's Northern Channel Islands

USGS Publications Warehouse

Reeder-Myers, Leslie; Erlandson, Jon M.; Muhs, Daniel R.; Rick, Torben C.

2015-01-01

Sea-level rise during the late Pleistocene and early Holocene inundated nearshore areas in many parts of the world, producing drastic changes in local ecosystems and obscuring significant portions of the archeological record. Although global forces are at play, the effects of sea-level rise are highly localized due to variability in glacial isostatic adjustment (GIA) effects. Interpretations of coastal paleoecology and archeology require reliable estimates of ancient shorelines that account for GIA effects. Here we build on previous models for California's Northern Channel Islands, producing more accurate late Pleistocene and Holocene paleogeographic reconstructions adjusted for regional GIA variability. This region has contributed significantly to our understanding of early New World coastal foragers. Sea level that was about 80–85 m lower than present at the time of the first known human occupation brought about a landscape and ecology substantially different than today. During the late Pleistocene, large tracts of coastal lowlands were exposed, while a colder, wetter climate and fluctuating marine conditions interacted with rapidly evolving littoral environments. At the close of the Pleistocene and start of the Holocene, people in coastal California faced shrinking land, intertidal, and subtidal zones, with important implications for resource availability and distribution.

Can sea level rise cause large submarine landslides on continental slopes?

NASA Astrophysics Data System (ADS)

Urlaub, Morelia

2014-05-01

Submarine landslides are one of the volumetrically most important sediment transport processes at continental margins. Moreover, these landslides are a major geohazard as they can cause damaging tsunamis and destroy seabed infrastructure. Due to their inaccessibility our understanding of what causes these landslides is limited and based on hypotheses that are difficult to test. Some of the largest submarine landslides, such as the Storegga Slide off Norway, occurred during times of eustatic sea level rise. It has been suggested that this global sea level rise was implicated in triggering of the landslides by causing an increase in excess pore pressure in the subseafloor. However, in a homogeneous slope a change in the thickness of the overlying water mass is not expected to affect its stability, as only the hydrostatic pressure component will change, whereas pore pressures in excess of hydrostatic will remain unaltered. Whether sufficiently rapid sea level rise, aided by rather impermeable sediment and complex layering, could cause excess pore pressures that may destabilise a continental slope is more difficult to answer and has not yet been tested. I use Finite Element Modelling to explore and quantify the direct effect of changes in the thickness of the overlying water mass on the stability of a generic sediment column with different stratigraphic conditions and hydro-mechanical properties. The results show that the direct effect of sea level rise on continental slope stability is minimal. Nevertheless, sea level rise may foster other processes, such as lithospheric stress changes resulting in increased seismicity, that could potentially cause large submarine landslides on continental slopes.

Will fluctuations in salt marsh–mangrove dominance alter vulnerability of a subtropical wetland to sea‐level rise?

USGS Publications Warehouse

Mckee, Karen L.; Vervaeke, William

2018-01-01

To avoid submergence during sea-level rise, coastal wetlands build soil surfaces vertically through accumulation of inorganic sediment and organic matter. At climatic boundaries where mangroves are expanding and replacing salt marsh, wetland capacity to respond to sea-level rise may change. To compare how well mangroves and salt marshes accommodate sea-level rise, we conducted a manipulative field experiment in a subtropical plant community in the subsiding Mississippi River Delta. Experimental plots were established in spatially equivalent positions along creek banks in monospecific stands of Spartina alterniflora (smooth cordgrass) or Avicennia germinans (black mangrove) and in mixed stands containing both species. To examine the effect of disturbance on elevation dynamics, vegetation in half of the plots was subjected to freezing (mangrove) or wrack burial (salt marsh), which caused shoot mortality. Vertical soil development was monitored for 6 years with the surface elevation table-marker horizon system. Comparison of land movement with relative sea-level rise showed that this plant community was experiencing an elevation deficit (i.e., sea level was rising faster than the wetland was building vertically) and was relying on elevation capital (i.e., relative position in the tidal frame) to survive. Although Avicennia plots had more elevation capital, suggesting longer survival, than Spartina or mixed plots, vegetation type had no effect on rates of accretion, vertical movement in root and sub-root zones, or net elevation change. Thus, these salt marsh and mangrove assemblages were accreting sediment and building vertically at equivalent rates. Small-scale disturbance of the plant canopy also had no effect on elevation trajectories—contrary to work in peat-forming wetlands showing elevation responses to changes in plant productivity. The findings indicate that in this deltaic setting with strong physical influences controlling elevation (sediment accretion, subsidence), mangrove replacement of salt marsh, with or without disturbance, will not necessarily alter vulnerability to sea-level rise.

Sea-level rise along the Emilia-Romagna coast (Northern Italy) in 2100: scenarios and impacts

NASA Astrophysics Data System (ADS)

Perini, Luisa; Calabrese, Lorenzo; Luciani, Paolo; Olivieri, Marco; Galassi, Gaia; Spada, Giorgio

2017-12-01

As a consequence of climate change and land subsidence, coastal zones are directly impacted by sea-level rise. In some particular areas, the effects on the ecosystem and urbanisation are particularly enhanced. We focus on the Emilia-Romagna (E-R) coastal plain in Northern Italy, bounded by the Po river mouth to the north and by the Apennines to the south. The plain is ˜ 130 km long and is characterised by wide areas below mean sea level, in part made up of reclaimed wetlands. In this context, several morphodynamic factors make the shore and back shore unstable. During next decades, the combined effects of land subsidence and of the sea-level rise as a result of climate change are expected to enhance the shoreline instability, leading to further retreat. The consequent loss of beaches would impact the economy of the region, which is tightly connected with tourism infrastructures. Furthermore, the loss of wetlands and dunes would threaten the ecosystem, which is crucial for the preservation of life and the environment. These specific conditions show the importance of a precise definition of the possible local impacts of the ongoing and future climate variations. The aim of this work is the characterisation of vulnerability in different sectors of the coastal plain and the recognition of the areas in which human intervention is urgently required. The Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5) sea-level scenarios are merged with new high-resolution terrain models, current data for local subsidence and predictions of the flooding model in_CoastFlood in order to develop different scenarios for the impact of sea-level rise projected to year 2100. First, the potential land loss due to the combined effect of subsidence and sea-level rise is extrapolated. Second, the increase in floodable areas as a result of storm surges is quantitatively determined. The results are expected to support the regional mitigation and adaptation strategies designed in response to climate change.

Effects of dietary n-3 highly unsaturated fatty acids (HUFAs) on growth, fatty acid profiles, antioxidant capacity and immunity of sea cucumber Apostichopus japonicus (Selenka).

PubMed

Yu, Haibo; Gao, Qinfeng; Dong, Shuanglin; Zhou, Jishu; Ye, Zhi; Lan, Ying

2016-07-01

The present study was conducted to understand the effects of dietary n-3 highly unsaturated fatty acids (HUFAs) on growth, fatty acid profiles, antioxidant capacity and the immunity of sea cucumber Apostichopus japonicus (Selenka). Five experimental diets were prepared, containing graded levels of n-3 HUFAs (0.46%, 0.85%, 1.25%, 1.61% and 1.95%, respectively), and the 0.46% group was used as control group. The specific growth rates, fatty acid profiles, activities and gene expression of antioxidative enzymes and lysozyme of the sea cucumbers that were fed with the 5 experimental diets were determined. The results showed that the specific growth rate of sea cucumbers in all the treatment groups significantly increased compared to the control group (P < 0.05), indicating the positive effects of n-3 HUFAs on the growth of sea cucumbers. The contents of eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3) in the body wall of the sea cucumbers gradually increased with the increasing levels of n-3 HUFAs in the diets. The suitable supplement of n-3 HUFAs in diets improved the activities of superoxide dismutase (SOD) and catalase (CAT) of sea cucumbers by up-regulating the expression of SOD and CAT mRNA in sea cucumbers. However, excess n-3 HUFAs in diets caused lipid peroxidation, inhibited the expression of lysozyme (LSZ) mRNA and decreased the activities of LSZ in sea cucumbers. In summary, the suitable supplement levels of n-3 HUFAs in diets of sea cucumbers A. japonicus were estimated between 0.85% and 1.25% considering the growth performance, cost and the indicators of antioxidant capacity and immunity. Copyright © 2016 Elsevier Ltd. All rights reserved.

Predicting impact of SLR on coastal flooding in Banda Aceh coastal defences

NASA Astrophysics Data System (ADS)

Al'ala, Musa; Syamsidik, Kato, Shigeru

2017-10-01

Banda Aceh is a low-lying city located at the northern tip of Sumatra Island and situated at the conjuncture of Malacca Strait and the Andaman Sea. A Sea Level Rise (SLR) rate at 7 mm/year has been observed around this region. In the next 50 years, this city will face a serious challenge to encounter impacts of the sea level rise, such as frequent coastal floodings. This study is aimed at estimating impacts of the sea level rise induced coastal floodings on several types of coastal structures and city drainage system. Numerical simulations of Delft3D were applied to investigate the influence of the gradual sea level rise in 50 years. The hydrodynamic process of coastal flooding and sediment transport were simulated by Delft3D-Flow. Topography and bathymetry data were collected from GEBCO and updated with the available nautical chart (DISHIDROS, JICA, and field measurements). Hydrodynamic process gains the flow process revealing the level of the sea water intrusion also observed in the model. Main rivers (Krueng Aceh, Krueng Neng, and Alue Naga Flood Canal) and the drainage system were observed to see the tides effects on coastal structures and drainage system. The impact on coastal community focusing on affected area, shoreline retreat, the rate of sea intrusion was analyzed with spatial tools. New coastal line, coastal flooding vulnerable area, and the community susceptibility properties map influenced by 50 years sea level rise is produced. This research found that the city needs to address strategies to anticipate the exacerbating impacts of the sea level rise by managing its coastal spatial planning and modify its drainage system, especially at the drainage outlets.

Strategic environmental assessment (SEA) for wind energy planning: Lessons from the United Kingdom and Germany

DOE Office of Scientific and Technical Information (OSTI.GOV)

Phylip-Jones, J., E-mail: jonesjp@liverpool.ac.uk; Fischer, T.B., E-mail: fischer@liv.ac.uk

This paper reports on SEA applied in the wind energy sector in the UK and Germany. Based on a review of 18 SEAs, it is found that the quality of SEA documentation is variable, with over a third of them being deemed unsatisfactory. Furthermore, SEA processes are conducted to varying degrees of effectiveness, with scoping a strength but impact prediction and mitigation weaknesses. Generally speaking, the influence of SEA on German wind energy plan making was found to be low and the influence of SEA on UK plans deemed to be moderate. The German plans had a low influence mainlymore » because of a perceived high environmental performance of the underlying plans in the first instance. Substantive outcomes of SEA are not always clear and the influence of SEA on decision making is said to be limited in many cases. Finally, a lack of effective tiering between SEA and project level EIA is also observed. In addition, our findings echo some of the weaknesses of SEA practice found in previous studies of SEA effectiveness, including poor impact prediction and significance sections and a lack of detailed monitoring programmes for post plan implementation.« less

Plant-Derived Polyphenols Interact with Staphylococcal Enterotoxin A and Inhibit Toxin Activity

PubMed Central

Shimamura, Yuko; Aoki, Natsumi; Sugiyama, Yuka; Tanaka, Takashi; Murata, Masatsune; Masuda, Shuichi

2016-01-01

This study was performed to investigate the inhibitory effects of 16 different plant-derived polyphenols on the toxicity of staphylococcal enterotoxin A (SEA). Plant-derived polyphenols were incubated with the cultured Staphylococcus aureus C-29 to investigate the effects of these samples on SEA produced from C-29 using Western blot analysis. Twelve polyphenols (0.1–0.5 mg/mL) inhibited the interaction between the anti-SEA antibody and SEA. We examined whether the polyphenols could directly interact with SEA after incubation of these test samples with SEA. As a result, 8 polyphenols (0.25 mg/mL) significantly decreased SEA protein levels. In addition, the polyphenols that interacted with SEA inactivated the toxin activity of splenocyte proliferation induced by SEA. Polyphenols that exerted inhibitory effects on SEA toxic activity had a tendency to interact with SEA. In particular, polyphenol compounds with 1 or 2 hexahydroxydiphenoyl groups and/or a galloyl group, such as eugeniin, castalagin, punicalagin, pedunculagin, corilagin and geraniin, strongly interacted with SEA and inhibited toxin activity at a low concentration. These polyphenols may be used to prevent S. aureus infection and staphylococcal food poisoning. PMID:27272505

Plant-Derived Polyphenols Interact with Staphylococcal Enterotoxin A and Inhibit Toxin Activity.

PubMed

Shimamura, Yuko; Aoki, Natsumi; Sugiyama, Yuka; Tanaka, Takashi; Murata, Masatsune; Masuda, Shuichi

2016-01-01

This study was performed to investigate the inhibitory effects of 16 different plant-derived polyphenols on the toxicity of staphylococcal enterotoxin A (SEA). Plant-derived polyphenols were incubated with the cultured Staphylococcus aureus C-29 to investigate the effects of these samples on SEA produced from C-29 using Western blot analysis. Twelve polyphenols (0.1-0.5 mg/mL) inhibited the interaction between the anti-SEA antibody and SEA. We examined whether the polyphenols could directly interact with SEA after incubation of these test samples with SEA. As a result, 8 polyphenols (0.25 mg/mL) significantly decreased SEA protein levels. In addition, the polyphenols that interacted with SEA inactivated the toxin activity of splenocyte proliferation induced by SEA. Polyphenols that exerted inhibitory effects on SEA toxic activity had a tendency to interact with SEA. In particular, polyphenol compounds with 1 or 2 hexahydroxydiphenoyl groups and/or a galloyl group, such as eugeniin, castalagin, punicalagin, pedunculagin, corilagin and geraniin, strongly interacted with SEA and inhibited toxin activity at a low concentration. These polyphenols may be used to prevent S. aureus infection and staphylococcal food poisoning.

Understanding Climate Change and Sea Level: A Case Study of Middle School Student Comprehension and An Evaluation of Tide Gauges off the Panama Canal in the Pacific Ocean and Caribbean Sea

NASA Astrophysics Data System (ADS)

Millan-Otoya, Juan C.

The present study had two main objectives. The first was to determine the degree of understanding of climate change, sea level and sea level rise among middle school students. Combining open-ended questions with likert-scaled questions, we identified student conceptions on these topics in 86 students from 7th and 8th grades during 2012 and 2013 before and after implementing a Curriculum Unit (CU). Additional information was obtained by adding drawings to the open-ended questions during the second year to gauge how student conceptions varied from a verbal and a visual perspective. Misconceptions were identified both pre- and post-CU among all the topics taught. Students commonly used climate and climate change as synonyms, sea level was often defined as water depth, and several students failed to understand the complexities that determine changes in sea level due to wind, tides, and changes in sea surface temperature. In general, 8th grade students demonstrated a better understanding of these topics, as reflected in fewer apparent misconceptions after the CU. No previous study had reported such improvement. This showed the value of implementing short lessons. Using Piaget's theories on cognitive development, the differences between 7th and 8th grade students reflect a transition to a more mature level which allowed students to comprehend more complex concepts that included multiple variables. The second objective was to determine if the frequency of sea level maxima not associated with tides over the last 100 years increased in two tide gauges located on the two extremes of the Panama canal, i.e. Balboa in the Pacific Ocean and Cristobal in the Caribbean Sea. These records were compared to time series of regional sea surface temperature, wind speed, atmospheric pressure, and El Nino-Southern Oscillation (ENSO), to determine if these played a role as physical drivers of sea level at either location. Neither record showed an increase in the frequency of sea level maxima events. No parameter analyzed explained variability in sea level maxima in Cristobal. There was a significant correlation between the zonal component of the wind and sea level at Balboa for the early record (r=0.153; p-value<0.05), but for the most part the p-values did not support the hypothesis of a correlation. Similarly, sea surface temperature had an effect on sea level at Balboa, but the null hypothesis that there is no correlation could not be rejected (p-value>0.05). There was a clear relationship between sea level maxima and ENSO. 70% of the years with higher counts of higher sea level events corresponded to El Nino years. A randomization test with 1000 iterations, shuffling the El Nino years, showed most of these randomizations grouped between 14-35% of the events occurring during a randomized El Nino year. In no iteration did the percentage of events that occurred during El Nino years rise above 65%. The correlation with zonal wind and the probable correlation with sea surface temperature can be linked via ENSO, since ENSO is associated with changes in the strength of the Trade Winds and positive anomalies in the sea surface temperature of the tropical Pacific Ocean.

Intraseasonal variability of sea level and circulation in the Gulf of Thailand: the role of the Madden-Julian Oscillation

NASA Astrophysics Data System (ADS)

Oliver, Eric C. J.

2014-01-01

Intraseasonal variability of the tropical Indo-Pacific ocean is strongly related to the Madden-Julian Oscillation (MJO). Shallow seas in this region, such as the Gulf of Thailand, act as amplifiers of the direct ocean response to surface wind forcing by efficient setup of sea level. Intraseasonal ocean variability in the Gulf of Thailand region is examined using statistical analysis of local tide gauge observations and surface winds. The tide gauges detect variability on intraseasonal time scales that is related to the MJO through its effect on local wind. The relationship between the MJO and the surface wind is strongly seasonal, being most vigorous during the monsoon, and direction-dependent. The observations are then supplemented with simulations of sea level and circulation from a fully nonlinear barotropic numerical ocean model (Princeton Ocean Model). The numerical model reproduces well the intraseasonal sea level variability in the Gulf of Thailand and its seasonal modulations. The model is then used to map the wind-driven response of sea level and circulation in the entire Gulf of Thailand. Finally, the predictability of the setup and setdown signal is discussed by relating it to the, potentially predictable, MJO index.

Combined effects of projected sea level rise, storm surge, and peak river flows on water levels in the Skagit Floodplain

USGS Publications Warehouse

Hamman, Josheph J; Hamlet, Alan F.; Fuller, Roger; Grossman, Eric E.

2016-01-01

Current understanding of the combined effects of sea level rise (SLR), storm surge, and changes in river flooding on near-coastal environments is very limited. This project uses a suite of numerical models to examine the combined effects of projected future climate change on flooding in the Skagit floodplain and estuary. Statistically and dynamically downscaled global climate model scenarios from the ECHAM-5 GCM were used as the climate forcings. Unregulated daily river flows were simulated using the VIC hydrology model, and regulated river flows were simulated using the SkagitSim reservoir operations model. Daily tidal anomalies (TA) were calculated using a regression approach based on ENSO and atmospheric pressure forcing simulated by the WRF regional climate model. A 2-D hydrodynamic model was used to estimate water surface elevations in the Skagit floodplain using resampled hourly hydrographs keyed to regulated daily flood flows produced by the reservoir simulation model, and tide predictions adjusted for SLR and TA. Combining peak annual TA with projected sea level rise, the historical (1970–1999) 100-yr peak high water level is exceeded essentially every year by the 2050s. The combination of projected sea level rise and larger floods by the 2080s yields both increased flood inundation area (+ 74%), and increased average water depth (+ 25 cm) in the Skagit floodplain during a 100-year flood. Adding sea level rise to the historical FEMA 100-year flood resulted in a 35% increase in inundation area by the 2040's, compared to a 57% increase when both SLR and projected changes in river flow were combined.

Sea Level Affecting Marshes Model (SLAMM) ‐ New functionality for predicting changes in distribution of submerged aquatic vegetation in response to sea level rise

USGS Publications Warehouse

Lee II, Henry; Reusser, Deborah A.; Frazier, Melanie R; McCoy, Lee M; Clinton, Patrick J.; Clough, Jonathan S.

2014-01-01

The “Sea‐Level Affecting Marshes Model” (SLAMM) is a moderate resolution model used to predict the effects of sea level rise on marsh habitats (Craft et al. 2009). SLAMM has been used extensively on both the west coast (e.g., Glick et al., 2007) and east coast (e.g., Geselbracht et al., 2011) of the United States to evaluate potential changes in the distribution and extent of tidal marsh habitats. However, a limitation of the current version of SLAMM, (Version 6.2) is that it lacks the ability to model distribution changes in seagrass habitat resulting from sea level rise. Because of the ecological importance of SAV habitats, U.S. EPA, USGS, and USDA partnered with Warren Pinnacle Consulting to enhance the SLAMM modeling software to include new functionality in order to predict changes in Zostera marina distribution within Pacific Northwest estuaries in response to sea level rise. Specifically, the objective was to develop a SAV model that used generally available GIS data and parameters that were predictive and that could be customized for other estuaries that have GIS layers of existing SAV distribution. This report describes the procedure used to develop the SAV model for the Yaquina Bay Estuary, Oregon, appends a statistical script based on the open source R software to generate a similar SAV model for other estuaries that have data layers of existing SAV, and describes how to incorporate the model coefficients from the site‐specific SAV model into SLAMM to predict the effects of sea level rise on Zostera marina distributions. To demonstrate the applicability of the R tools, we utilize them to develop model coefficients for Willapa Bay, Washington using site‐specific SAV data.

Analysis of Groundwater Anomalies Estimated by GRACE and GLDAS Satellite-based Hydrological Model in the Gulf of Mexico

NASA Astrophysics Data System (ADS)

Lotfata, A.; Ambinakudige, S.

2017-12-01

Coastal regions face a higher risk of flooding. A rise in sea-level increases flooding chances in low-lying areas. A major concern is the effect of sea-level rise on the depth of the fresh water/salt water interface in the aquifers of the coastal regions. A sea-level change rise impacts the hydrological system of the aquifers. Salt water intrusion into fresh water aquifers increase water table levels. Flooding prone areas in the coast are at a higher risk of salt water intrusion. The Gulf coast is one of the most vulnerable flood areas due to its natural weather patterns. There is not yet a local assessment of the relation between groundwater level and sea-level rising. This study investigates the projected sea-level rise models and the anomalous groundwater level during January 2002 to December 2016. We used the NASA Gravity Recovery and Climate Experiment (GRACE) and Global Land Data Assimilation System (GLDAS) satellite data in the analysis. We accounted the leakage error and the measurement error in GRACE data. GLDAS data was used to calculate the groundwater storage from the total water storage estimated using GRACE data (ΔGW=ΔTWS (soil moisture, surface water, groundwater, and canopy water) - ΔGLDAS (soil moisture, surface water, and canopy water)). The preliminary results indicate that the total water storage is increasing in parts of the Gulf of Mexico. GRACE data show high soil wetness and groundwater levels in Mississippi, Alabama and Texas coasts. Because sea-level rise increases the probability of flooding in the Gulf coast and affects the groundwater, we will analyze probable interactions between sea-level rise and groundwater in the study area. To understand regional sea-level rise patterns, we will investigate GRACE Ocean data along the Gulf coasts. We will quantify ocean total water storage, its salinity, and its relationship with the groundwater level variations in the Gulf coast.

Understanding sources of sea lice for salmon farms in Chile.

PubMed

Kristoffersen, A B; Rees, E E; Stryhn, H; Ibarra, R; Campisto, J-L; Revie, C W; St-Hilaire, S

2013-08-01

The decline of fisheries over recent decades and a growing human population has coincided with an increase in aquaculture production. As farmed fish densities increase, so have their rates of infectious diseases, as predicted by the theory of density-dependent disease transmission. One of the pathogen that has increased with the growth of salmon farming is sea lice. Effective management of this pathogen requires an understanding of the spatial scale of transmission. We used a two-part multi-scale model to account for the zero-inflated data observed in weekly sea lice abundance levels on rainbow trout and Atlantic salmon farms in Chile, and to assess internal (farm) and external (regional) sources of sea lice infection. We observed that the level of juvenile sea lice was higher on farms that were closer to processing plants with fish holding facilities. Further, evidence for sea lice exposure from the surrounding area was supported by a strong positive correlation between the level of juvenile sea lice on a farm and the number of gravid females on neighboring farms within 30 km two weeks prior. The relationship between external sources of sea lice from neighboring farms and juvenile sea lice on a farm was one of the strongest detected in our multivariable model. Our findings suggest that the management of sea lice should be coordinated between farms and should include all farms and processing plants with holding facilities within a relatively large geographic area. Understanding the contribution of pathogens on a farm from different sources is an important step in developing effective control strategies. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

Effect of Diets Supplemented with Different Sources of Astaxanthin on the Gonad of the Sea Urchin Anthocidaris crassispina

PubMed Central

Peng, Juan; Yuan, Jian-Ping; Wang, Jiang-Hai

2012-01-01

The effect of the microalgae Haematococcus pluvialis and Chorella zofingiensis, and synthetic astaxanthin on the gonad of the sea urchin Anthocidaris crassispina was studied. The basal diet was supplemented with H. pluvialis, C. zofingiensis, or synthetic astaxanthin, at two levels of astaxanthin (approximately 400 mg/kg and 100 mg/kg), to obtain the experimental diets HP1, HP2, CZ1, CZ2, AST1, and AST2, respectively, for two months of feeding experiment. The results showed that the concentrations of astaxanthin in the gonads of the sea urchins fed these experimental diets ranged from 0.15 to 3.01 mg/kg dry gonad weight. The higher astaxanthin levels (>2.90 mg/kg) were found in the gonads of the sea urchins fed the diets HP1 (containing 380 mg/kg of astaxanthins, mostly mono- and diesters) and AST1 (containing 385 mg/kg of synthetic astaxanthin). The lowest astaxanthin level (0.15 mg/kg) was detected in the gonads of the sea urchins fed the diet CZ2 (containing 98 mg/kg of astaxanthins, mostly diesters). Furthermore, the highest canthaxanthin level (7.48 mg/kg) was found in the gonads of the sea urchins fed the diet CZ1 (containing 387 mg/kg of astaxanthins and 142 mg/kg of canthaxanthin), suggesting that astaxanthins, especially astaxanthin esters, might not be assimilated as easily as canthaxanthin by the sea urchins. Our results show that sea urchins fed diets containing astaxanthin pigments show higher incorporation of these known antioxidant constituents, with the resultant seafood products therefore being of potential higher nutritive value. PMID:23016124

Sphingoid bases from sea cucumber induce apoptosis in human hepatoma HepG2 cells through p-AKT and DR5.

PubMed

Hossain, Zakir; Sugawara, Tatsuya; Hirata, Takashi

2013-03-01

Biofunctional marine compounds have recently received substantial attention for their nutraceutical characteristics. In this study, we investigated the apoptosis-inducing effects of sphingoid bases prepared from sea cucumber using human hepatoma HepG2 cells. Apoptotic effects were determined by cell viability assay, DNA fragmentation assay, caspase-3 and caspase-8 activities. The expression levels of apoptosis-inducing death receptor-5 (DR5) and p-AKT were assayed by western blot analysis, and mRNA expression of bax, GADD45 and PPARγ was assayed by quantitative RT-PCR analysis. Sphingoid bases from sea cucumber markedly reduced the cell viability of HepG2 cells. DNA fragmentation indicative of apoptosis was observed in a dose-dependent manner. The expression levels of the apoptosis inducer protein Bax were increased by the sphingoid bases from sea cucumber. GADD45, which plays an important role in apoptosis-inducing pathways, was markedly upregulated by sphingoid bases from sea cucumber. Upregulation of PPARγ mRNA was also observed during apoptosis induced by the sphingoid bases. The expression levels of DR5 and p-AKT proteins were increased and decreased, respectively, as a result of the effects of sphingoid bases from sea cucumber. The results indicate that sphingoid bases from sea cucumber induce apoptosis in HepG2 cells through upregulation of DR5, Bax, GADD45 and PPARγ and downregulation of p-AKT. Our results show for the first time the functional properties of marine sphingoid bases as inducers of apoptosis in HepG2 cells.

Improved simulation of Antarctic sea ice due to the radiative effects of falling snow

NASA Astrophysics Data System (ADS)

Li, J.-L. F.; Richardson, Mark; Hong, Yulan; Lee, Wei-Liang; Wang, Yi-Hui; Yu, Jia-Yuh; Fetzer, Eric; Stephens, Graeme; Liu, Yinghui

2017-08-01

Southern Ocean sea-ice cover exerts critical control on local albedo and Antarctic precipitation, but simulated Antarctic sea-ice concentration commonly disagrees with observations. Here we show that the radiative effects of precipitating ice (falling snow) contribute substantially to this discrepancy. Many models exclude these radiative effects, so they underestimate both shortwave albedo and downward longwave radiation. Using two simulations with the climate model CESM1, we show that including falling-snow radiative effects improves the simulations relative to cloud properties from CloudSat-CALIPSO, radiation from CERES-EBAF and sea-ice concentration from passive microwave sensors. From 50-70°S, the simulated sea-ice-area bias is reduced by 2.12 × 106 km2 (55%) in winter and by 1.17 × 106 km2 (39%) in summer, mainly because increased wintertime longwave heating restricts sea-ice growth and so reduces summer albedo. Improved Antarctic sea-ice simulations will increase confidence in projected Antarctic sea level contributions and changes in global warming driven by long-term changes in Southern Ocean feedbacks.

Effects of nonlethal sea lamprey attack on the blood chemistry of lake trout

USGS Publications Warehouse

Edsall, Carol Cotant; Swink, William D.

2001-01-01

A laboratory study examined changes in the blood chemistry of field-caught and hatchery-reared lake trout Salvelinus namaycush subjected to a nonlethal attack by sea lampreys Petromyzon marinus. We measured glucose, total protein, amylase, alkaline phosphatase (ALKP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatine kinase, calcium, magnesium, triglycerides, sodium, and potassium with a Kodak Ektachem DT60 Analyzer, Ektachem DTSC Module, and the DTE Module. Mean levels of total protein, AST, ALKP, hematocrit, calcium, magnesium, and sodium decreased significantly (Pa?? 0.05), and mean levels of ALT and potassium increased significantly (Pa?? 0.05) after sea lamprey feeding. Lake trout condition (K) and hematocrit levels also decreased significantly (Pa?? 0.05) after the sea lamprey attack. Frequency distributions of eight lake trout blood chemistry variables and the hematocrit were significantly different before and after a sea lamprey attack. A second study that used hatchery lake trout broodstock measured changes in hematocrit before and after a sea lamprey attack.

Influences of sediment redistribution on sea-level changes along the U.S. Atlantic margin since the mid-Pliocene

NASA Astrophysics Data System (ADS)

Li, Q.; Ferrier, K.; Austermann, J.; Mitrovica, J. X.

2017-12-01

The Orangeburg Scarp is a paleo-shoreline formed along the southeastern U.S. Atlantic coast during the mid-Pliocene warm period (MPWP; 3.3 - 2.9 Ma). The MPWP is a time of interest because it is often cited as an analog for modern climate and thus an important target for understanding sea-level responses to climate change. The present Orangeburg Scarp exhibits 40-meter variations in elevation along its length, implying that it has been warped since its formation, which complicates efforts to infer global ice volume at the MPWP. Previous studies have shown that the effects of glacial isostatic adjustment (GIA) and dynamic topography (DT) on sea level can explain a significant fraction of the observed variability in elevation along the Orangeburg Scarp. Here we build on these studies by using a gravitationally self-consistent ice age sea-level model to compute the effects of sediment loading and unloading on paleo-shoreline elevation since the mid-Pliocene. To constrain the sediment loading history in this region, we present a new compilation of erosion and deposition rates along the U.S. Atlantic margin, from which we generate a range of sediment redistribution scenarios since the MPWP. We simultaneously drive the sea-level model with these sediment redistribution histories and existing ice and dynamic topography histories. Our results show that sediment loading and unloading is capable of warping the elevation of this paleo-shoreline by 20 meters since its formation, similar in magnitude to the contributions from GIA and DT over the same time period. These results demonstrate that sediment redistribution can induce significant perturbations in sea-level markers from the MPWP, and thus accounting for its influence will improve reconstructions of sea level and global ice volume during the MPWP and perhaps other periods of relative ice age warmth.

Caribbean mangroves adjust to rising sea level through biotic controls on change in soil elevation

USGS Publications Warehouse

McKee, K.L.; Cahoon, D.R.; Feller, Ilka C.

2007-01-01

Aim The long-term stability of coastal ecosystems such as mangroves and salt marshes depends upon the maintenance of soil elevations within the intertidal habitat as sea level changes. We examined the rates and processes of peat formation by mangroves of the Caribbean Region to better understand biological controls on habitat stability. Location Mangrove-dominated islands on the Caribbean coasts of Belize, Honduras and Panama were selected as study sites. Methods Biological processes controlling mangrove peat formation were manipulated (in Belize) by the addition of nutrients (nitrogen or phosphorus) to Rhizophora mangle (red mangrove), and the effects on the dynamics of soil elevation were determined over a 3-year period using rod surface elevation tables (RSET) and marker horizons. Peat composition and geological accretion rates were determined at all sites using radiocarbon-dated cores. Results The addition of nutrients to mangroves caused significant changes in rates of mangrove root accumulation, which influenced both the rate and direction of change in elevation. Areas with low root input lost elevation and those with high rates gained elevation. These findings were consistent with peat analyses at multiple Caribbean sites showing that deposits (up to 10 m in depth) were composed primarily of mangrove root matter. Comparison of radiocarbon-dated cores at the study sites with a sea-level curve for the western Atlantic indicated a tight coupling between peat building in Caribbean mangroves and sea-level rise over the Holocene. Main conclusions Mangroves common to the Caribbean region have adjusted to changing sea level mainly through subsurface accumulation of refractory mangrove roots. Without root and other organic inputs, submergence of these tidal forests is inevitable due to peat decomposition, physical compaction and eustatic sea-level rise. These findings have relevance for predicting the effects of sea-level rise and biophysical processes on tropical mangrove ecosystems.

Coastal vulnerability assessment of the Northern Gulf of Mexico to sea-level rise and coastal change

USGS Publications Warehouse

Pendleton, E.A.; Barras, J.A.; Williams, S.J.; Twichell, D.C.

2010-01-01

A coastal vulnerability index (CVI) was used to map the relative vulnerability of the coast to future sea-level rise along the Northern Gulf of Mexico from Galveston, TX, to Panama City, FL. The CVI ranks the following in terms of their physical contribution to sea-level rise-related coastal change: geomorphology, regional coastal slope, rate of relative sea-level rise, historical shoreline change rate, mean tidal range, and mean significant wave height. The rankings for each variable are combined and an index value is calculated for 1-kilometer grid cells along the coast. The CVI highlights those regions where the physical effects of sea-level rise might be the greatest. The CVI assessment presented here builds on an earlier assessment conducted for the Gulf of Mexico. Recent higher resolution shoreline change, land loss, elevation, and subsidence data provide the foundation for a better assessment for the Northern Gulf of Mexico. The areas along the Northern Gulf of Mexico that are likely to be most vulnerable to sea-level rise are parts of the Louisiana Chenier Plain, Teche-Vermillion Basin, and the Mississippi barrier islands, as well as most of the Terrebonne and Barataria Bay region and the Chandeleur Islands. These very high vulnerability areas have the highest rates of relative sea-level rise and the highest rates of shoreline change or land area loss. The information provided by coastal vulnerability assessments can be used in long-term coastal management and policy decision making.

Adriatic storm surges and related cross-basin sea-level slope

NASA Astrophysics Data System (ADS)

Međugorac, Iva; Orlić, Mirko; Janeković, Ivica; Pasarić, Zoran; Pasarić, Miroslava

2018-05-01

Storm surges pose a severe threat to the northernmost cities of the Adriatic coast, with Venice being most prone to flooding. It has been noted that some flooding episodes cause significantly different effects along the eastern and western Adriatic coasts, with indications that the difference is related to cross-basin sea-level slope. The present study aims to determine specific atmospheric conditions under which the slope develops and to explore connection with increased sea level along the two coastlines. The analysis is based on sea-level time series recorded at Venice and Bakar over the 1984-2014 interval, from which 38 most intensive storm-surge episodes were selected, and their meteorological backgrounds (ERA-Interim) were studied. The obtained sea-level extremes were grouped into three categories according to their cross-basin sea-level slope: storm surges that slope strongly westward (W type), those that slope eastward (E type) and ordinary storm surges (O type). Results show that the slope is controlled by wind action only, specifically, by the wind component towards a particular coast and by the cross-basin shear of along-basin wind. Meteorological fields were used to force an oceanographic numerical model in order to confirm the empirically established connection between the atmospheric forcing and the slope. Finally, it has been found that the intensity of storm surges along a particular Adriatic coast is determined by an interplay of sea-level slopes in the along and cross-basin directions.

Extremely low genetic diversity across mangrove taxa reflects past sea level changes and hints at poor future responses.

PubMed

Guo, Zixiao; Li, Xinnian; He, Ziwen; Yang, Yuchen; Wang, Wenqing; Zhong, Cairong; Greenberg, Anthony J; Wu, Chung-I; Duke, Norman C; Shi, Suhua

2018-04-01

The projected increases in sea levels are expected to affect coastal ecosystems. Tropical communities, anchored by mangrove trees and having experienced frequent past sea level changes, appear to be vibrant at present. However, any optimism about the resilience of these ecosystems is premature because the impact of past climate events may not be reflected in the current abundance. To assess the impact of historical sea level changes, we conducted an extensive genetic diversity survey on the Indo-Malayan coast, a hotspot with a large global mangrove distribution. A survey of 26 populations in six species reveals extremely low genome-wide nucleotide diversity and hence very small effective population sizes (N e ) in all populations. Whole-genome sequencing of three mangrove species further shows the decline in N e to be strongly associated with the speed of past changes in sea level. We also used a recent series of flooding events in Yalong Bay, southern China, to test the robustness of mangroves to sea level changes in relation to their genetic diversity. The events resulted in the death of half of the mangrove trees in this area. Significantly, less genetically diverse mangrove species suffered much greater destruction. The dieback was accompanied by a drastic reduction in local invertebrate biodiversity. We thus predict that tropical coastal communities will be seriously endangered as the global sea level rises. Well-planned coastal development near mangrove forests will be essential to avert this crisis. © 2017 John Wiley & Sons Ltd.

Sea-Level Trend Uncertainty With Pacific Climatic Variability and Temporally-Correlated Noise

NASA Astrophysics Data System (ADS)

Royston, Sam; Watson, Christopher S.; Legrésy, Benoît; King, Matt A.; Church, John A.; Bos, Machiel S.

2018-03-01

Recent studies have identified climatic drivers of the east-west see-saw of Pacific Ocean satellite altimetry era sea level trends and a number of sea-level trend and acceleration assessments attempt to account for this. We investigate the effect of Pacific climate variability, together with temporally-correlated noise, on linear trend error estimates and determine new time-of-emergence (ToE) estimates across the Indian and Pacific Oceans. Sea-level trend studies often advocate the use of auto-regressive (AR) noise models to adequately assess formal uncertainties, yet sea level often exhibits colored but non-AR(1) noise. Standard error estimates are over- or under-estimated by an AR(1) model for much of the Indo-Pacific sea level. Allowing for PDO and ENSO variability in the trend estimate only reduces standard errors across the tropics and we find noise characteristics are largely unaffected. Of importance for trend and acceleration detection studies, formal error estimates remain on average up to 1.6 times those from an AR(1) model for long-duration tide gauge data. There is an even chance that the observed trend from the satellite altimetry era exceeds the noise in patches of the tropical Pacific and Indian Oceans and the south-west and north-east Pacific gyres. By including climate indices in the trend analysis, the time it takes for the observed linear sea-level trend to emerge from the noise reduces by up to 2 decades.

The Sea Level Fingerprints of Global Change

NASA Astrophysics Data System (ADS)

Mitrovica, J. X.; Hay, C.; Kopp, R. E., III; Morrow, E.

2014-12-01

It may be difficult to persuade those living in northern Europe that the sea level changes that their coastal communities face depends less on the total melting of polar ice sheets and glaciers than on the individual contributions to this total. In particular, melting of a specific ice sheet or mountain glacier drives deformational, gravitational and rotational perturbations to the Earth system that are manifest in a unique geometry, or fingerprint, of global sea level change. For example, melting from the Greenland Ice Sheet equivalent to 1 mm/yr of global mean sea level (GMSL) rise will lead to sea level rise of ~0 mm/yr in Dublin, ~0.2 mm/yr in Amsterdam, ~0.4 mm/yr in Boston and ~1.2 mm/yr in Cape Town. In contrast, if the same volume of ice melted from the West Antarctic Ice Sheet, all of the above sites would experience a sea level rise in the range 1.1-1.2 mm/yr. These fingerprints of modern ice melting, together with ocean thermal expansion and dynamic effects, and the ongoing signal from glacial isostatic adjustment in response to the last ice age, combine to produce a sea level field with significant geographic variability. In this talk I will highlight an analysis of global tide gauge records that takes full advantage of this variability to estimate both GMSL and the sources of meltwater over the last century, and to project GMSL to the end of the current century.

Sea-Level Allowances along the World Coastlines

NASA Astrophysics Data System (ADS)

Vandewal, R.; Tsitsikas, C.; Reerink, T.; Slangen, A.; de Winter, R.; Muis, S.; Hunter, J. R.

2017-12-01

Sea level changes as a result of climate change. For projections we take ocean mass changes and volume changes into account. Including gravitational and rotational fingerprints this provide regional sea level changes. Hence we can calculate sea-level rise patterns based on CMIP5 projections. In order to take the variability around the mean state, which follows from the climate models, into account we use the concept of allowances. The allowance indicates the height a coastal structure needs to be increased to maintain the likelihood of sea-level extremes. Here we use a global reanalysis of storm surges and extreme sea levels based on a global hydrodynamic model in order to calculate allowances. It is shown that the model compares in most regions favourably with tide gauge records from the GESLA data set. Combining the CMIP5 projections and the global hydrodynamical model we calculate sea-level allowances along the global coastlines and expand the number of points with a factor 50 relative to tide gauge based results. Results show that allowances increase gradually along continental margins with largest values near the equator. In general values are lower at midlatitudes both in Northern and Southern Hemisphere. Increased risk for extremes are typically 103-104 for the majority of the coastline under the RCP8.5 scenario at the end of the century. Finally we will show preliminary results of the effect of changing wave heights based on the coordinated ocean wave project.

Soil organic matter decomposition follows plant productivity response to sea-level rise

NASA Astrophysics Data System (ADS)

Mueller, Peter; Jensen, Kai; Megonigal, James Patrick

2015-04-01

The accumulation of soil organic matter (SOM) is an important mechanism for many tidal wetlands to keep pace with sea-level rise. SOM accumulation is governed by the rates of production and decomposition of organic matter. While plant productivity responses to sea-level rise are well understood, far less is known about the response of SOM decomposition to accelerated sea-level rise. Here we quantified the effects of sea-level rise on SOM decomposition by exposing planted and unplanted tidal marsh monoliths to experimentally manipulated flood duration. The study was performed in a field-based mesocosm facility at the Smithsonian Global Change Research Wetland, a micro tidal brackish marsh in Maryland, US. SOM decomposition was quantified as CO2 efflux, with plant- and SOM-derived CO2 separated using a stable carbon isotope approach. Despite the dogma that decomposition rates are inversely related to flooding, SOM mineralization was not sensitive to varying flood duration over a 35 cm range in surface elevation in unplanted mesocoms. In the presence of plants, decomposition rates were strongly and positively related to aboveground biomass (p≤0.01, R2≥0.59). We conclude that rates of soil carbon loss through decomposition are driven by plant responses to sea level in this intensively studied tidal marsh. If our result applies more generally to tidal wetlands, it has important implications for modeling carbon sequestration and marsh accretion in response to accelerated sea-level rise.

Meteorological conditions influencing the formation of level ice within the Baltic Sea

NASA Astrophysics Data System (ADS)

Mazur, A. K.; Krezel, A.

2012-12-01

The Baltic Sea is covered by ice every winter and on average, the ice-covered area is 45% of the total area of the Baltic Sea. The beginning of ice season usually starts in the end of November, ice extent is the largest between mid-February and mid-March and sea ice disappears completely in May. The ice covered areas during a typical winter are the Gulf of Bothnia, the Gulf of Finland and the Gulf of Riga. The studies of sea ice in the Baltic Sea are related to two aspects: climate and marine transport. Depending on the local weather conditions during the winter different types of sea ice can be formed. From the point of winter shipping it is important to locate level and deformed ice areas (rafted ice, ridged ice, and hummocked ice). Because of cloud and daylight independency as well as good spatial resolution, SAR data seems to be the most suitable source of data for sea ice observation in the comparatively small area of the Baltic Sea. We used ASAR Wide Swath Mode data with spatial resolution 150 m. We analyzed data from the three winter seasons which were examples of severe, typical and mild winters. To remove the speckle effect the data were resampled to 250 m pixel size and filtred using Frost filter 5x5. To detect edges we used Sobel filter. The data were also converted into grayscale. Sea ice classification was based on Object-Based Image Analysis (OBIA). Object-based methods are not a common tool in sea ice studies but they seem to accurately separate level ice within the ice pack. The data were segmented and classified using eCognition Developer software. Level ice were classified based on texture features defined by Haralick (Grey Level Co-Occurrence Matrix homogeneity, GLCM contrast, GLCM entropy and GLCM correlation). The long-term changes of the Baltic Sea ice conditions have been already studied. They include date of freezing, date of break-up, sea ice extent and some of work also ice thickness. There is a little knowledge about the relationship of short term changes in sea ice cover and meteorological conditions. In following studies we analyzed the formation of level sea ice depending on some weather conditions (temperature, humidity, pressure at sea level, 10 meter wind). It can be clearly seen that the most important factors influencing formation of level ice are the temperature and wind.

Sea-level feedback lowers projections of future Antarctic Ice-Sheet mass loss

PubMed Central

Gomez, Natalya; Pollard, David; Holland, David

2015-01-01

The stability of marine sectors of the Antarctic Ice Sheet (AIS) in a warming climate has been identified as the largest source of uncertainty in projections of future sea-level rise. Sea-level fall near the grounding line of a retreating marine ice sheet has a stabilizing influence on the ice sheets, and previous studies have established the importance of this feedback on ice age AIS evolution. Here we use a coupled ice sheet–sea-level model to investigate the impact of the feedback mechanism on future AIS retreat over centennial and millennial timescales for a range of emission scenarios. We show that the combination of bedrock uplift and sea-surface drop associated with ice-sheet retreat significantly reduces AIS mass loss relative to a simulation without these effects included. Sensitivity analyses show that the stabilization tends to be greatest for lower emission scenarios and Earth models characterized by a thin elastic lithosphere and low-viscosity upper mantle, as is the case for West Antarctica. PMID:26554381

Experimental investigation of channel avulsion frequency on river deltas under rising sea levels

NASA Astrophysics Data System (ADS)

Silvestre, J.; Chadwick, A. J.; Steele, S.; Lamb, M. P.

2017-12-01

River deltas are low-relief landscapes that are socioeconomically important; they are home to over half a billion people worldwide. Many deltas are built by cycles of lobe growth punctuated by abrupt channel shifts, or avulsions, which often reoccur at a similar location and with a regular frequency. Previous experimental work has investigated the effect of hydrodynamic backwater in controlling channel avulsion location and timing on deltas under constant sea level conditions, but it is unclear how sea-level rise impacts avulsion dynamics. We present results from a flume experiment designed to isolate the role of relative sea-level rise on the evolution of a backwater-influenced delta. The experiment was conducted in the river-ocean facility at Caltech, where a 7m long, 14cm wide alluvial river drains into a 6m by 3m "ocean" basin. The experimental delta grew under subcritical flow, a persistent backwater zone, and a range of sea level rise rates. Without sea level rise, lobe progradation produced in-channel aggradation and periodic avulsions every 3.6 ± 0.9 hours, which corresponded to when channels aggraded to approximately one-half of their flow depth. With a modest rate of sea-level rise (0.25 mm/hr), we observed enhanced aggradation in the backwater zone, causing channels to aggrade more quickly and avulse more frequently (every 2.1 ± 0.6 hours). In future work, we expect further increases in the rate of relative sea-level rise to cause avulsion frequency to decrease as the delta drowns and the backwater zone retreats upstream. Experimental results can serve as tests of numerical models that are needed for hazard mitigation and coastal sustainability efforts on drowning deltas.

A Bayesian network to predict coastal vulnerability to sea level rise

USGS Publications Warehouse

Gutierrez, B.T.; Plant, N.G.; Thieler, E.R.

2011-01-01

Sea level rise during the 21st century will have a wide range of effects on coastal environments, human development, and infrastructure in coastal areas. The broad range of complex factors influencing coastal systems contributes to large uncertainties in predicting long-term sea level rise impacts. Here we explore and demonstrate the capabilities of a Bayesian network (BN) to predict long-term shoreline change associated with sea level rise and make quantitative assessments of prediction uncertainty. A BN is used to define relationships between driving forces, geologic constraints, and coastal response for the U.S. Atlantic coast that include observations of local rates of relative sea level rise, wave height, tide range, geomorphic classification, coastal slope, and shoreline change rate. The BN is used to make probabilistic predictions of shoreline retreat in response to different future sea level rise rates. Results demonstrate that the probability of shoreline retreat increases with higher rates of sea level rise. Where more specific information is included, the probability of shoreline change increases in a number of cases, indicating more confident predictions. A hindcast evaluation of the BN indicates that the network correctly predicts 71% of the cases. Evaluation of the results using Brier skill and log likelihood ratio scores indicates that the network provides shoreline change predictions that are better than the prior probability. Shoreline change outcomes indicating stability (-1 1 m/yr) was not well predicted. We find that BNs can assimilate important factors contributing to coastal change in response to sea level rise and can make quantitative, probabilistic predictions that can be applied to coastal management decisions. Copyright ?? 2011 by the American Geophysical Union.

Changes in Sea Levels around the British Isles Revisited (Invited)

NASA Astrophysics Data System (ADS)

Teferle, F. N.; Hansen, D. N.; Bingley, R. M.; Williams, S. D.; Woodworth, P. L.; Gehrels, W. R.; Bradley, S. L.; Stocchi, P.

2009-12-01

Recently a number of new and/or updated sources for estimates of vertical land movements for the British Isles have become available allowing the relative and average changes in sea levels for this region to be revisited. The geodetic data set stems from a combination of re-processed continuous Global Positioning System (GPS) measurements from stations in the British Isles and from a global reference frame network, and absolute gravity (AG) measurements from two stations in the British Isles. The geologic data set of late Holocene sea level indicators has recently been updated, now applying corrections for the 20th century sea level rise, syphoning effect and late Holocene global ice melt, and expanded to Northern Ireland and Ireland. Several new model predictions of the glacial isostatic adjustment (GIA) process active in this region form the modelling data set of vertical land movements for the British Isles. Correcting the updated revised local reference (RLR) trends from the Permanent Service for Mean Sea Level (PSMSL) with these vertical land movement data sets, regional and averaged changes in sea levels around the British Isles have been investigated. Special focus is thereby also given to the coastal areas that have recently been identified within the UK Climate Projections 2009.

Temporal response of hydraulic head, temperature, and chloride concentrations to sea-level changes, Floridan aquifer system, USA

NASA Astrophysics Data System (ADS)

Hughes, J. D.; Vacher, H. L.; Sanford, Ward E.

2009-06-01

Three-dimensional density-dependent flow and transport modeling of the Floridan aquifer system, USA shows that current chloride concentrations are not in equilibrium with current sea level and, second, that the geometric configuration of the aquifer has a significant effect on system responses. The modeling shows that hydraulic head equilibrates first, followed by temperatures, and then by chloride concentrations. The model was constructed using a modified version of SUTRA capable of simulating multi-species heat and solute transport, and was compared to pre-development conditions using hydraulic heads, chloride concentrations, and temperatures from 315 observation wells. Three hypothetical, sinusoidal sea-level changes occurring over 100,000 years were used to evaluate how the simulated aquifer responds to sea-level changes. Model results show that hydraulic head responses lag behind sea-level changes only where the Miocene Hawthorn confining unit is thick and represents a significant restriction to flow. Temperatures equilibrate quickly except where the Hawthorn confining unit is thick and the duration of the sea-level event is long (exceeding 30,000 years). Response times for chloride concentrations to equilibrate are shortest near the coastline and where the aquifer is unconfined; in contrast, chloride concentrations do not change significantly over the 100,000-year simulation period where the Hawthorn confining unit is thick.

Rapid response of tidal channel networks to sea-level variations (Venice Lagoon, Italy)

NASA Astrophysics Data System (ADS)

Rizzetto, Federica; Tosi, Luigi

2012-07-01

The aim of the present paper is to examine the effects of long- and short-term sea-level fluctuations (i.e. relative sea-level rise and tides) on the geomorphologic evolution of modern tidal channels through the joint interpretation of channel modifications, the 1938-2010 yearly time series of relative sea-level rise, and the variations of strength and frequency of high tides which occurred in the same period. We analyzed a salt marsh area not particularly modified by human interventions, located in the northern Venice Lagoon, Italy. The availability of a long historical record of high-resolution aerial photographs provided us the opportunity to reconstruct in detail the evolution of the drainage patterns from 1938 to the present. Results from our analyses gave us information about the degree of control of long- and short-term sea-level fluctuations on planimetric development of tidal channels and provided demonstration of the rapid response of the drainage network to these oscillations. We found that both relative sea-level rise and high tide frequency greatly influenced salt marsh margin shift and meander evolution of tidal channels in the long term, but short-term sinuosity changes of creeks were often also closely related to tide variations. Channels nearer the marsh margin were more exposed to the action of the increasing tides.

Development of a Geographic Information System (GIS) tool for the preliminary assessment of the effects of predicted sea level and tidal change on transportation infrastructure.

DOT National Transportation Integrated Search

2013-09-01

In this project, researchers from the University of Florida developed a sketch planning tool that can be used to conduct statewide and regional assessments of transportation facilities potentially vulnerable to sea level change trends. Possible futur...

Nature, Humans, and the Coastal Zone.

ERIC Educational Resources Information Center

Walker, H. Jesse

1990-01-01

Considers the interface of humans and seacoasts over time. Explains how coastal zones are formed and human attempts to defend against sea level changes. Charts the percentage of major world cities that also are ports. Postulates how the greenhouse effect could influence sea level, examining potential human responses to changes in coastal zones.…

PROJECTING POPULATION-LEVEL RESPONSE OF PURPLE SEA URCHINS TO LEAD CONTAMINATION FOR AN ESTUARINE ECOLOGICAL RISK ASSESSMENT

EPA Science Inventory

As part of an ecological risk assessment case study at the Portsmouth naval Shipyard (PNS), Kittery, Maine, USA, the population level effects of lead exposure to purple sea urchin, Arbacia punctulata, were investigated using a stage-classified matrix population model. The model d...

HUFF, a One-Dimensional Hydrodynamics Code for Strong Shocks

DTIC Science & Technology

1978-12-01

results for two sample problems. The first problem discussed is a one-kiloton nuclear burst in infinite sea level air. The second problem is the one...of HUFF as an effective first order hydro- dynamic computer code. 1 KT Explosion The one-kiloton nuclear explosion in infinite sea level air was

Nutrient enrichment and precipitation changes do not enhance resiliency of salt marshes to sea level rise in the Northeastern U.S.

EPA Science Inventory

In the U.S. Northeast, salt marshes are exceptionally vulnerable to the effects of accelerated sea level rise as compensatory mechanisms relying on positive feedbacks between inundation and sediment deposition are insufficient to counter inundation increases in low turbidity tida...

Science Support for Climate Change Adaptation in South Florida

USGS Publications Warehouse

Early, Laura M.; Harvey, Rebecca G.

2010-01-01

Earth's changing climate is among the foremost conservation challenges of the 21st century, threatening to permanently alter entire ecosystems and contribute to extinctions of species. Lying only a few feet above sea level and already suffering effects of anthropogenic stressors, south Florida's ecosystems are particularly vulnerable to negative impacts of climate change. Recent research accounting for the gravitational effects of melting ice sheets predicts that sea level rise on U.S. coastlines will be much higher than global averages (Gomez et al. 2010), and the Miami-Dade Climate Change Advisory Task Force predicts that local sea level rise will be at least 3 to 5 ft. (0.9 m to 1.5 m) by 2100 (MDCCATF 2008). In a 5 ft. scenario, up to 873 additional square miles of the Everglades would be inundated with saltwater (see maps below). Accelerated sea level rise is likely to be accompanied by increasing temperatures (IPCC 2007a) and more intense tropical storms and hurricanes (Webster et al. 2005). In addition, changes in amount, timing, and distribution of rainfall in south Florida may lead to more severe droughts and floods (SFWMD 2009).

Potential increase in coastal wetland vulnerability to sea-level rise suggested by considering hydrodynamic attenuation effects

PubMed Central

Rodríguez, José F.; Saco, Patricia M.; Sandi, Steven; Saintilan, Neil; Riccardi, Gerardo

2017-01-01

The future of coastal wetlands and their ecological value depend on their capacity to adapt to the interacting effects of human impacts and sea-level rise. Even though extensive wetland loss due to submergence is a possible scenario, its magnitude is highly uncertain due to limited understanding of hydrodynamic and bio-geomorphic interactions over time. In particular, the effect of man-made drainage modifications on hydrodynamic attenuation and consequent wetland evolution is poorly understood. Predictions are further complicated by the presence of a number of vegetation types that change over time and also contribute to flow attenuation. Here, we show that flow attenuation affects wetland vegetation by modifying its wetting-drying regime and inundation depth, increasing its vulnerability to sea-level rise. Our simulations for an Australian subtropical wetland predict much faster wetland loss than commonly used models that do not consider flow attenuation. PMID:28703130

Potential increase in coastal wetland vulnerability to sea-level rise suggested by considering hydrodynamic attenuation effects

NASA Astrophysics Data System (ADS)

Rodríguez, José F.; Saco, Patricia M.; Sandi, Steven; Saintilan, Neil; Riccardi, Gerardo

2017-07-01

The future of coastal wetlands and their ecological value depend on their capacity to adapt to the interacting effects of human impacts and sea-level rise. Even though extensive wetland loss due to submergence is a possible scenario, its magnitude is highly uncertain due to limited understanding of hydrodynamic and bio-geomorphic interactions over time. In particular, the effect of man-made drainage modifications on hydrodynamic attenuation and consequent wetland evolution is poorly understood. Predictions are further complicated by the presence of a number of vegetation types that change over time and also contribute to flow attenuation. Here, we show that flow attenuation affects wetland vegetation by modifying its wetting-drying regime and inundation depth, increasing its vulnerability to sea-level rise. Our simulations for an Australian subtropical wetland predict much faster wetland loss than commonly used models that do not consider flow attenuation.

Inversion of Solid Earth's Varying Shape 2: Using Self-Consistency to Infer Static Ocean Topography

NASA Astrophysics Data System (ADS)

Blewitt, G.; Clarke, P. J.

2002-12-01

We have developed a spectral approach to invert for the redistribution of mass on the Earth's surface given precise global geodetic measurements of the solid Earth's geometrical shape. We used the elastic load Love number formalism to characterize the redistributed mass as a spherical harmonic expansion, truncated at some degree and order n. [Clarke and Blewitt, this meeting]. Here we incorporate the additional physical constraint that the sea surface in hydrostatic equilibrium corresponds to an equipotential surface, to infer the non-steric component of static ocean topography. Our model rigorously accounts for self-gravitation of the ocean, continental surface mass, and the deformed solid Earth, such that the sea surface adopts a new equipotential surface consistent with ocean-land mass exchange, deformation of the geoid, deformation of the sea floor, and the geographical configuration of the oceans and continents. We develop a self-consistent spectral inversion method to solve for the distribution of continental surface mass that would generate geographic variations in relative mean sea level such that the total (ocean plus continental) mass distribution agrees with the original geodetic estimates to degree and order n. We apply this theory to study the contribution of seasonal inter-hemispheric (degree-1) mass transfer to seasonal variation in static ocean topography, using a published empirical seasonal model for degree-1 surface loading derived using GPS coordinate time series from the global IGS network [Blewitt et al., Science 294, 2,342-2,345, 2001]. The resulting predictions of seasonal variations of relative sea level strongly depend on location, with peak variations ranging from 3 mm to 19 mm. The largest peak variations are predicted in mid-August around Antarctica and the southern hemisphere in general; the lowest variations are predicted in the northern hemisphere. Corresponding maximum continental loading occurs in Canada and Siberia at the water-equivalent level of 200 mm. The RMS spatial variability about global mean sea level at any given time is 20% for geocentric sea level (as measured by satellite altimetry) versus relative sea level, which is a consequence of degree-1 sea floor displacement in the center of figure frame. While land-ocean mass exchange governs global mean relative sea level, at any given point the contribution of geoid deformation to relative sea level can be of similar magnitude, and so can almost cancel or double the effect of change in global mean sea level.While the sea surface takes on the shape of the deformed geoid, the sea surface everywhere seasonally oscillates about the deformed geoid with annual amplitude 6.1 mm. This effect is due mainly to an 8.0+/- 0.7~mm contribution from land-ocean mass exchange, which is then reduced by a 1.9 mm seasonal variation in the mean geoid height above the sea floor (to which a mass-conserved ocean cannot respond). Of this, 0.4 mm is due to the mean geocentric height of the sea floor, and 1.5 mm is due to the mean geocentric height of the geoid over oceanic areas. The seasonal gradients predicted by our inversion might be misinterpreted as basin-scale dynamics. Also, the oceans amplify a land degree-1 load by 20--30%, which suggests that deformation (and models of geocenter displacements) would be sensitive to the accuracy of ocean bottom pressure, particularly in the southern hemisphere.

Supplementation of arachidonic acid rich oil in European sea bass juveniles (Dicentrarchus labrax) diets: Effects on leucocytes and plasma fatty acid profiles, selected immune parameters and circulating prostaglandins levels.

PubMed

Torrecillas, S; Román, L; Rivero-Ramírez, F; Caballero, M J; Pascual, C; Robaina, L; Izquierdo, M S; Acosta, F; Montero, D

2017-05-01

The main objective of this study was to assess the effects of graded levels of dietary arachidonic acid (ARA), supplemented from alternative sources, on fatty acid composition of plasma and head kidney leucocytes of European sea bass (Dicentrarchus labrax). For that purpose, sea bass juveniles were fed four diets containing graded levels of ARA as follows: 0.5% (ARA0.5), 1% (ARA1), 2% (ARA2) and 4% (ARA4) during 60 days. At the end of the feeding trial fatty acid profiles of plasma and head kidney leucocytes were analyzed. Besides, plasma prostaglandins levels, head kidney leucocytes respiratory burst activity; peroxidase activity and phagocytic index were assayed. Reducing dietary ARA levels below 1% markedly reduced European sea bass growth performance. However, fish fed diet ARA0.5 tried to compensate this dietary ARA deficiency by a selective deposition of ARA on plasma and head kidney leucocytes, reaching similar levels to those fish fed diet ARA1 after 60 days of feeding. Nevertheless, head kidney phagocytic capacity was reduced as dietary ARA content in relation not only to variations on membrane composition but also to changes on fish basal prostaglandins levels. Results obtained demonstrated the importance to supply the necessary quantity n-6 LC-PUFA, and not only n-3 LC-PUFA levels, in European sea bass diets, in relation to not only growth performance but also immune system function. Copyright © 2017 Elsevier Ltd. All rights reserved.

Preliminary investigation of the effects of sea-level rise on groundwater levels in New Haven, Connecticut

USGS Publications Warehouse

Bjerklie, David M.; Mullaney, John R.; Stone, Janet R.; Skinner, Brian J.; Ramlow, Matthew A.

2012-01-01

Global sea level rose about 0.56 feet (ft) (170 millimeters (mm)) during the 20th century. Since the 1960s, sea level has risen at Bridgeport, Connecticut, about 0.38 ft (115 mm), at a rate of 0.008 ft (2.56 mm + or - 0.58 mm) per year. With regional subsidence, and with predicted global climate change, sea level is expected to continue to rise along the northeast coast of the United States through the 21st century. Increasing sea levels will cause groundwater levels in coastal areas to rise in order to adjust to the new conditions. Some regional climate models predict wetter climate in the northeastern United States under some scenarios. Scenarios for the resulting higher groundwater levels have the potential to inundate underground infrastructure in lowlying coastal cities. New Haven is a coastal city in Connecticut surrounded and bisected by tidally affected waters. Monitoring of water levels in wells in New Haven from August 2009 to July 2010 indicates the complex effects of urban influence on groundwater levels. The response of groundwater levels to recharge and season varied considerably from well to well. Groundwater temperatures varied seasonally, but were warmer than what was typical for Connecticut, and they seem to reflect the influence of the urban setting, including the effects of conduits for underground utilities. Specific conductance was elevated in many of the wells, indicating the influence of urban activities or seawater in Long Island Sound. A preliminary steady-state model of groundwater flow for part of New Haven was constructed using MODFLOW to simulate current groundwater levels (2009-2010) and future groundwater levels based on scenarios with a rise of 3 ft (0.91 meters (m)) in sea level, which is predicted for the end of the 21st century. An additional simulation was run assuming a 3-ft rise in sea level combined with a 12-percent increase in groundwater recharge. The model was constructed from existing hydrogeologic information for the New Haven area and from new information on groundwater levels collected during October 2009-June 2010. For the scenario with a 3-ft rise in sea level and no increase in recharge, simulated groundwater levels near the coast rose 3 ft; this increased water level tapered off toward a discharge area at the only nontidal stream in the study area. Simulated stream discharge increased at the nontidal stream because of the increased gradient. Although groundwater levels rose, the simulated difference between the groundwater levels in the aquifer and the increased sea level declined, indicating that the depth to the interface between freshwater and saltwater may possibly decline. Simulated water levels were affected by rise in sea level even in areas where the water table was at 17-24 ft (5.2-7.3 m) above current (2011) sea level. For the scenario with increased recharge, simulated groundwater levels were as much as an additional foot higher at some locations in the study area. The results of this preliminary investigation indicate that groundwater levels in coastal areas can be expected to rise and may rise higher if groundwater recharge also increases. This finding has implications for the disposal of stormwater through infiltration, a low-impact development practice designed to improve water quality and reduce overland peak discharge. Other implications include increased risk of basement flooding and increased groundwater seepage into underground sewer pipes and utility corridors in some areas. These implications will present engineering challenges to New Haven and Yale University. The preliminary model developed for this study can be the starting point for further simulation of future alternative scenarios for sea-level rise and recharge. Further simulations could identify those areas of New Haven where infrastructure may be at greatest risk from rising levels of groundwater. The simulations described in this report have limitations due to the preliminary scope of the work. Approaches to improve simulations include but are not limited to incorporating: * The variable density of seawater into the model in order to understand the current and future location of the interface between freshwater and saltwater; * Collection of additional data in order to better resolve temporal and spatial patterns in water levels in the aquifer; * Improved estimates of recharge through direct and indirect measurements of freshwater discharge from the study area; and * Transient simulations for greater understanding of the amount of time required for water levels and the position of the interface between freshwater and saltwater to adjust to changes in sea level and recharge.

Sea level rise drives increased tidal flooding frequency at tide gauges along the U.S. East and Gulf Coasts: Projections for 2030 and 2045.

PubMed

Dahl, Kristina A; Fitzpatrick, Melanie F; Spanger-Siegfried, Erika

2017-01-01

Tidal flooding is among the most tangible present-day effects of global sea level rise. Here, we utilize a set of NOAA tide gauges along the U.S. East and Gulf Coasts to evaluate the potential impact of future sea level rise on the frequency and severity of tidal flooding. Using the 2001-2015 time period as a baseline, we first determine how often tidal flooding currently occurs. Using localized sea level rise projections based on the Intermediate-Low, Intermediate-High, and Highest projections from the U.S. National Climate Assessment, we then determine the frequency and extent of such flooding at these locations for two near-term time horizons: 2030 and 2045. We show that increases in tidal flooding will be substantial and nearly universal at the 52 locations included in our analysis. Long before areas are permanently inundated, the steady creep of sea level rise will force many communities to grapple with chronic high tide flooding in the next 15 to 30 years.

Sea level rise drives increased tidal flooding frequency at tide gauges along the U.S. East and Gulf Coasts: Projections for 2030 and 2045

PubMed Central

Fitzpatrick, Melanie F.; Spanger-Siegfried, Erika

2017-01-01

Tidal flooding is among the most tangible present-day effects of global sea level rise. Here, we utilize a set of NOAA tide gauges along the U.S. East and Gulf Coasts to evaluate the potential impact of future sea level rise on the frequency and severity of tidal flooding. Using the 2001–2015 time period as a baseline, we first determine how often tidal flooding currently occurs. Using localized sea level rise projections based on the Intermediate-Low, Intermediate-High, and Highest projections from the U.S. National Climate Assessment, we then determine the frequency and extent of such flooding at these locations for two near-term time horizons: 2030 and 2045. We show that increases in tidal flooding will be substantial and nearly universal at the 52 locations included in our analysis. Long before areas are permanently inundated, the steady creep of sea level rise will force many communities to grapple with chronic high tide flooding in the next 15 to 30 years. PMID:28158209

The Effects of Snow Depth Forcing on Southern Ocean Sea Ice Simulations

NASA Technical Reports Server (NTRS)

Powel, Dylan C.; Markus, Thorsten; Stoessel, Achim

2003-01-01

The spatial and temporal distribution of snow on sea ice is an important factor for sea ice and climate models. First, it acts as an efficient insulator between the ocean and the atmosphere, and second, snow is a source of fresh water for altering the already weak Southern Ocean stratification. For the Antarctic, where the ice thickness is relatively thin, snow can impact the ice thickness in two ways: a) As mentioned above snow on sea ice reduces the ocean-atmosphere heat flux and thus reduces freezing at the base of the ice flows; b) a heavy snow load can suppress the ice below sea level which causes flooding and, with subsequent freezing, a thickening of the sea ice (snow-to-ice conversion). In this paper, we compare different snow fall paramterizations (incl. the incorporation of satellite-derived snow depth) and study the effect on the sea ice using a sea ice model.

Studying the impact of climate change on flooding in large river basins

NASA Astrophysics Data System (ADS)

Thiele-Eich, I.; Hopson, T.; Gilleland, E.; Lamarque, J.-F.; Hu, A.; Simmer, C.

2012-04-01

Assessing the potential impact of global climate change on hydrological extremes becomes crucial for regions such as Bangladesh, where a high population density results in a large exposure to risks associated with extreme flooding. In addition, low-lying countries such as Bangladesh are especially vulnerable to sea-level rise and its influence on present-day flood characteristics. By combining the impact of climate change on upper catchment precipitation as well as on sea-level rise at the river mouths, we attempt to analyze the development of flood characteristics such as frequency and magnitude in large river basins. Since flood duration is also of great importance to people exposed to flooding, the development of the number of days with extreme flooding is evaluated for possible trends in the future. Data used includes historical observations from the Global Runoff Data Centre, while recently released model output for upper catchment precipitation and annual mean thermosteric sea-level rise is taken from the four CCSM4 1° 20th Century ensemble members, as well as from six CCSM4 1° ensemble members for the reference concentration pathway scenarios RCP8.5, 6.0, 4.5 and 2.6. A peak-over-threshold approach is used to quantify the expected future changes in flood return levels, where discharge exceedances over a certain threshold are fit to a Generalized Pareto Distribution. Return levels are compared from both 20th century and future model simulations for time slices at 2030, 2050, 2070 and 2090. It can be seen that return periods of flood events decrease as the 21st century progresses in all RCP scenarios, with this shift most pronounced in RCP 8.5. The evaluation of flood duration, or the number of days with discharges above a certain threshold, yields an increase. While the number of days with flooding increases in all RCP scenarios, with the largest increase seen at the end of the 21st century, this increase is only statistically significant for RCP 8.5. Finally, we study how sea-level rise governs the flooding behavior further upstream by calculating the effective additional discharge due to the backwater effect of sea-level rise. Sea-level rise anomalies for the 21st century are taken from CCSM4 model output at each of the river mouths. Judging from our work, the increase in effective discharge due to sea-level rise cannot be neglected when discussing flooding in the respective river basins. Impact of sea-level rise on changes in return levels will be investigated further by using extreme-value theory to calculate how the tails of the current river discharge distribution will be shifted by changing climate.

Evaluation of the effects of sea-level change and coastal canal management on saltwater intrusion in the Biscayne aquifer of south Florida, USA

NASA Astrophysics Data System (ADS)

Hughes, J. D.; Sifuentes, D. F.; White, J.

2015-12-01

Sea-level increases are expected to have an effect on the position of the freshwater-saltwater interface in the Biscayne aquifer in south Florida as a result of the low topographic relief of the area and high rates of groundwater withdrawal from the aquifer. To study the effects that future sea-level increases will have on saltwater intrusion in the Biscayne aquifer in Broward County, Florida, a three-dimensional, variable-density, groundwater-flow and transport model was developed. The model was calibrated to observed groundwater heads and chloride concentrations for a 62-year period that includes historic increases in sea level, development of a surface-water management system to control flooding, and increases in groundwater withdrawals as the area transitioned from agricultural to urban land uses. Sensitivity analyses indicate that downward leakage of saltwater from coastal canals and creeks was the primary source of saltwater to the Biscayne aquifer during the last 62-years in areas where the surface-water system is not actively managed and is tidally influenced. In areas removed from the coastal canals and creeks or under active surface-water management, historic groundwater withdrawals were the primary cause of saltwater intrusion into the aquifer. Simulation of future conditions suggests that possible increases in sea level will result in additional saltwater intrusion. Model scenarios suggest that additional saltwater intrusion will be greatest in areas where coastal canals and creeks were historically the primary source of seawater. Future saltwater intrusion in those areas, however, may be reduced by relocation of salinity-control structures.

Constraining Future Sea Level Rise Estimates from the Amundsen Sea Embayment, West Antarctica

NASA Astrophysics Data System (ADS)

Nias, I.; Cornford, S. L.; Edwards, T.; Gourmelen, N.; Payne, A. J.

2016-12-01

The Amundsen Sea Embayment (ASE) is the primary source of mass loss from the West Antarctic Ice Sheet. The catchment is particularly susceptible to grounding line retreat, because the ice sheet is grounded on bedrock that is below sea level and deepening towards its interior. Mass loss from the ASE ice streams, which include Pine Island, Thwaites and Smith glaciers, is a major uncertainty on future sea level rise, and understanding the dynamics of these ice streams is essential to constraining this uncertainty. The aim of this study is to construct a distribution of future ASE sea level contributions from an ensemble of ice sheet model simulations and observations of surface elevation change. A 284 member ensemble was performed using BISICLES, a vertically-integrated ice flow model with adaptive mesh refinement. Within the ensemble parameters associated with basal traction, ice rheology and sub-shelf melt rate were perturbed, and the effect of bed topography and sliding law were also investigated. Initially each configuration was run to 50 model years. Satellite observations of surface height change were then used within a Bayesian framework to assign likelihoods to each ensemble member. Simulations that better reproduced the current thinning patterns across the catchment were given a higher score. The resulting posterior distribution of sea level contributions is narrower than the prior distribution, although the central estimates of sea level rise are similar between the prior and posterior. The most extreme simulations were eliminated and the remaining ensemble members were extended to 200 years, using a simple melt rate forcing.

A nonstationary analysis for the Northern Adriatic extreme sea levels

NASA Astrophysics Data System (ADS)

Masina, Marinella; Lamberti, Alberto

2013-09-01

The historical data from the Trieste, Venice, Porto Corsini, and Rimini tide gauges have been used to investigate the spatial and temporal changes in extreme high water levels in the Northern Adriatic. A detailed analysis of annual mean sea level evolution at the three longest operating stations shows a coherent behavior both on a regional and global scale. A slight increase in magnitude of extreme water elevations, after the removal of the regularized annual mean sea level necessary to eliminate the effect of local subsidence and sea level rise, is found at the Venice and Porto Corsini stations. It seems to be mainly associated with a wind regime change occurred in the 1990s, due to an intensification of Bora wind events after their decrease in frequency and intensity during the second half of the 20th century. The extreme values, adjusted for the annual mean sea level trend, are modeled using a time-dependent GEV distribution. The inclusion of seasonality in the GEV parameters considerably improves the data fitting. The interannual fluctuations of the detrended monthly maxima exhibit a significant correlation with the variability of the large-scale atmospheric circulation represented by the North Atlantic Oscillation and Arctic Oscillation indices. The different coast exposure to the Bora and Sirocco winds and their seasonal character explain the various seasonal patterns of extreme sea levels observed at the tide gauges considered in the present analysis.

Correlated environmental corrections in TOPEX/POSEIDON, with a note on ionospheric accuracy

NASA Technical Reports Server (NTRS)

Zlotnicki, V.

1994-01-01

Estimates of the effectiveness of an altimetric correction, and interpretation of sea level variability as a response to atmospheric forcing, both depend upon assuming that residual errors in altimetric corrections are uncorrelated among themselves and with residual sea level, or knowing the correlations. Not surprisingly, many corrections are highly correlated since they involve atmospheric properties and the ocean surface's response to them. The full corrections (including their geographically varying time mean values), show correlations between electromagnetic bias (mostly the height of wind waves) and either atmospheric pressure or water vapor of -40%, and between atmospheric pressure and water vapor of 28%. In the more commonly used collinear differences (after removal of the geographically varying time mean), atmospheric pressure and wave height show a -30% correlation, atmospheric pressure and water vapor a -10% correlation, both pressure and water vapor a 7% correlation with residual sea level, and a bit surprisingly, ionospheric electron content and wave height a 15% correlation. Only the ocean tide is totally uncorrelated with other corrections or residual sea level. The effectiveness of three ionospheric corrections (TOPEX dual-frequency, a smoothed version of the TOPEX dual-frequency, and Doppler orbitography and radiopositioning integrated by satellite (DORIS) is also evaluated in terms of their reduction in variance of residual sea level. Smooth (90-200 km along-track) versions of the dual-frequency altimeter ionosphere perform best both globally and within 20 deg in latitude from the equator. The noise variance in the 1/s TOPEX inospheric samples is approximately (11 mm) squared, about the same as noise in the DORIS-based correction; however, the latter has its error over scales of order 10(exp 3) km. Within 20 deg of the equator, the DORIS-based correction adds (14 mm) squared to the residual sea level variance.

Sea-level changes in the Lopingian (late Permian) of the northwestern Tethys and their effects on the terrestrial palaeoenvironments, biota and fossil preservation

NASA Astrophysics Data System (ADS)

Kustatscher, Evelyn; Bernardi, Massimo; Petti, Fabio Massimo; Franz, Matthias; van Konijnenburg-van Cittert, Johanna H. A.; Kerp, Hans

2017-01-01

The Lopingian is characterised by an aridisation trend and substantial sea-level changes. Hence, the fossil record of this time interval is strongly affected by ecological and taphonomic factors inherent to these long-term processes. Integrated sedimentological and palaeontological studies in the Bletterbach Gorge (Dolomites, N-Italy) allow discrimination between biological signals and preservational bias, shedding light on the effect of sea-level changes on the preservation potential of terrestrial associations of plant remains and tetrapod footprints. Flora A, composed of more humid elements with larger leaf/shoot fragments, appears close to a sea-level highstand and is interpreted as a (par-)autochthonous assemblage of an intrazonal riparian vegetation. Flora B, dominated by xerophytic elements documented by smaller fragments, corresponds to an allochthonous assemblage of an azonal vegetation preserved in floodplain fines of a progradational fluvial plain associated with a sea-level lowstand. The distribution of vertebrate footprints mirrors that of the plant-bearing horizons and their abundance and morphological diversity strongly increases in correspondence with marine transgressions. This could be related to a more diverse fauna (more complex food-web related to more humid conditions) or more favourable taphonomic conditions. However, the most diversified fauna, recorded during the early phases of the regressive phase, is in our interpretation best explained by the rapid burial of footprints due to the increasing energy. Our study provides an explanation for the change in distribution and preservation of plant and animal fossils in the Bletterbach section and shows how the fossil content of continental successions is deeply influenced by sea-level changes.

Absolute Sea-level Changes Derived from Integrated Geodetic Datasets (1955-2016) in the Caribbean Sea

NASA Astrophysics Data System (ADS)

Yang, L.; Wang, G.; Liu, H.

2017-12-01

Rising sea level has important direct impacts on coastal and island regions such as the Caribbean where the influence of sea-level rise is becoming more apparent. The Caribbean Sea is a semi-enclosed sea adjacent to the landmasses of South and Central America to the south and west, and the Greater Antilles and the Lesser Antilles separate it from the Atlantic Ocean to the north and east. The work focus on studying the relative and absolute sea-level changes by integrating tide gauge, GPS, and satellite altimetry datasets (1955-2016) within the Caribbean Sea. Further, the two main components of absolute sea-level change, ocean mass and steric sea-level changes, are respectively studied using GRACE, temperature, and salinity datasets (1955-2016). According to the analysis conducted, the sea-level change rates have considerable temporal and spatial variations, and estimates may be subject to the techniques used and observation periods. The average absolute sea-level rise rate is 1.8±0.3 mm/year for the period from 1955 to 2015 according to the integrated tide gauge and GPS observations; the average absolute sea-level rise rate is 3.5±0.6 mm/year for the period from 1993 to 2016 according to the satellite altimetry observations. This study shows that the absolute sea-level change budget in the Caribbean Sea is closed in the periods from 1955 to 2016, in which ocean mass change dominates the absolute sea-level rise. The absolute sea-level change budget is also closed in the periods from 2004 to 2016, in which steric sea-level rise dominates the absolute sea-level rise.

Advanced Regional and Decadal Predictions of Coastal Inundation for the U.S. Atlantic and Gulf Coasts

NASA Astrophysics Data System (ADS)

Horton, B. P.; Donnelly, J. P.; Corbett, D. R.; Kemp, A.; Lindeman, K.; Mann, M. E.; Peltier, W. R.; Rahmstorf, S.

2012-12-01

Future inundation of the US Atlantic and Gulf coasts will depend upon both sea-level rise and the intensity and frequency of tropical cyclones, each of which will be affected by climate change. In this proposal, we will employ new interdisciplinary approaches to bring about a step change in the reliability of predictions of such inundation. The rate of sea-level rise along the US Atlantic and Gulf coasts has increased throughout the 20th century. Whilst there is widespread agreement that it continue to accelerate during the 21st century, great uncertainty surrounds its magnitude and geographic distribution. Key uncertainties include the role of continental ice sheets, mountain glaciers and ocean density changes. Insufficient understanding of these complex physical processes precludes accurate prediction of sea-level rise. New approaches using semi-empirical models that relate instrumental records of climate and sea-level rise have projected up to 2 m of sea-level rise by AD 2100. But the time span of instrumental sea-level records is insufficient to adequately constrain the climate:sea-level relationship. Here, we produce new high resolution proxy data of sea-level and temperature to provide crucial additional constraints to such semi-empirical models. Our dataset will span the alternation between the "Medieval Climate Anomaly" and "Little Ice Age". Before the models can provide appropriate data for coastal management and planning, they must be complemented with regional estimates of sea-level rise. Therefore, the proxy sea-level data has been collected from six study areas (Massachusetts, New Jersey, North Carolina, Georgia and Atlantic and Gulf coasts of Florida) to accommodate the required extent of regional variability. In the case of inundation arising from tropical cyclones, the historical and observational records are insufficient for predicting their nature and recurrence, because they are such extreme and rare events. Moreover, in the future, the resultant storm surges will be superimposed on background sea-level rise. To overcome these problems, we couple regional sea-level rise projections with hurricane simulations and storm surge models to map coastal inundation for the current climate and the best and worst case climate scenarios of the IPCC AR4. The products of this proposal will raise the bar for the scientific prediction of region-specific inundation probabilities in terms of coordinated semi-empirical proxy data, hindcast- and forecast-driven sea-level modeling and tropical cyclone forecasting. To optimize transfer of this often complex information for effective adaptive decision-making by managers and planners, we will systematically review >800 adaptation reports and consult early and often with primary endusers to identify their exact needs. We will produce high penetration print and web products for diverse audiences, specific to each region.

Observing and Studying Extreme Low Pressure Events with Altimetry

PubMed Central

Carrère, Loren; Mertz, Françoise; Dorandeu, Joel; Quilfen, Yves; Patoux, Jerome

2009-01-01

The ability of altimetry to detect extreme low pressure events and the relationship between sea level pressure and sea level anomalies during extra-tropical depressions have been investigated. Specific altimeter treatments have been developed for tropical cyclones and applied to obtain a relevant along-track sea surface height (SSH) signal: the case of tropical cyclone Isabel is presented here. The S- and C-band measurements are used because they are less impacted by rain than the Ku-band, and new sea state bias (SSB) and wet troposphere corrections are proposed. More accurate strong altimeter wind speeds are computed thanks to the Young algorithm. Ocean signals not related to atmospheric pressure can be removed with accuracy, even within a Near Real Time context, by removing the maps of sea level anomaly (SLA) provided by SSALTO/Duacs. In the case of Extra-Tropical Depressions, the classical altimeter processing can be used. Ocean signal not related to atmospheric pressure is along-track filtered. The sea level pressure (SLP)-SLA relationship is investigated for the North Atlantic, North Pacific and Indian oceans; three regression models are proposed allowing restoring an altimeter SLP with a mean error of 5 hPa if compared to ECMWF or buoys SLP. The analysis of barotropic simulation outputs points out the regional variability of the SLP/Model Sea Level relationship and the wind effects. PMID:22573955

Terrestrial Waters and Sea Level Variations on Interannual Time Scale

NASA Technical Reports Server (NTRS)

Llovel, W.; Becker, M.; Cazenave, A.; Jevrejeva, S.; Alkama, R.; Decharme, B.; Douville, H.; Ablain, M.; Beckley, B.

2011-01-01

On decadal to multi-decadal time scales, thermal expansion of sea waters and land ice loss are the main contributors to sea level variations. However, modification of the terrestrial water cycle due to climate variability and direct anthropogenic forcing may also affect sea level. For the past decades, variations in land water storage and corresponding effects on sea level cannot be directly estimated from observations because these are almost non-existent at global continental scale. However, global hydrological models developed for atmospheric and climatic studies can be used for estimating total water storage. For the recent years (since mid-2002), terrestrial water storage change can be directly estimated from observations of the GRACE space gravimetry mission. In this study, we analyse the interannual variability of total land water storage, and investigate its contribution to mean sea level variability at interannual time scale. We consider three different periods that, each, depend on data availability: (1) GRACE era (2003-2009), (2) 1993-2003 and (3) 1955-1995. For the GRACE era (period 1), change in land water storage is estimated using different GRACE products over the 33 largest river basins worldwide. For periods 2 and 3, we use outputs from the ISBA-TRIP (Interactions between Soil, Biosphere, and Atmosphere-Total Runoff Integrating Pathways) global hydrological model. For each time span, we compare change in land water storage (expressed in sea level equivalent) to observed mean sea level, either from satellite altimetry (periods 1 and 2) or tide gauge records (period 3). For each data set and each time span, a trend has been removed as we focus on the interannual variability. We show that whatever the period considered, interannual variability of the mean sea level is essentially explained by interannual fluctuations in land water storage, with the largest contributions arising from tropical river basins.

XXI century projections of wind-wave conditions and sea-level rise in the Black sea

NASA Astrophysics Data System (ADS)

Polonsky, A.; Garmashov, A.; Fomin, V.; Valchev, N.; Trifonova, E.

2012-04-01

Projection of regional climate changes for XXI century is one of the priorities of EC environmental programme. Potential worsening of the waves' statistics, sea level rise and extreme surges are the principal negative consequences of the climate change for marine environment. That is why the main purpose of this presentation is to discuss the above issue for the Black sea region (with a strong focus to the south-west subregion because the maximum heights of waves exceeding 10 m occur just here) using output of several global coupled models (GCM) for XXI century, wave simulation, long-term observations of sea level and statistical techniques. First of all we tried to choose the best coupled model (s) simulated the Black sea climate change and variability using the control experiments for 20 century (203). The principal result is as follows. There is not one model which is simulating adequately even one atmospheric parameter for all seasons. Therefore we considered (for the climate projection) different outputs form various models. When it was possible we calculated also the ensemble mean projection for the selected model (s) and emission scenarios. To calculate the wave projection we used the output of SWAN model forced by the GCM wind projection for 2010 to 2100. To estimate the sea level rise in XXI century and future surges statistics we extrapolate the observed sea level rise tendencies, statistical relation between wave heights and sea level and wave scenarios. Results show that in general, the climate change in XXI century doesn't lead to the catastrophic change of the Black sea wind-wave statistics including the extreme waves in the S-W Black sea. The typical atmospheric pattern leading to the intense storm in the S-W Black sea is characterized by the persistent anticyclonic area to the North of the Black sea and cyclonic conditions in the Southern Black sea region. Such pressure pattern causes persistent and strong eastern or north-eastern wind which generates the high waves in the S-E Black sea. The climate projections show that the frequency of such atmospheric pattern will not principally increase. The recent probability of the extreme wave height (exceeding 8 to10 m) in the S-W Black sea (~1 occurrence per 10 years) will not be much worse in XXI century. Similar conclusion is true for the storm surges along the Bulgarian coastline. Expected sea level rise in the Black sea basin for XXI century due to regional climate changes is about 2 mm per year (±50%). However, some Black sea subregions (such as Odessa and Varna bay) are characterized by fivefold sea level rise because of the local land subsidence. So, this geomorphologic effect is the most dangerous local consequence for the sustainable development and management of the coastal zone in such subregions. This study was supported by EC project "THESEUS".

Indicators' role: How do they influence Strategic Environmental Assessment and Sustainable Planning - The Chinese experience.

PubMed

Gao, Jingjing; Christensen, Per; Kørnøv, Lone

2017-08-15

As an information carrier and communication medium, indicators provide useful decision-making assistance in setting process goals and effectively reaching the goals. The main focus of this article is to investigate indicators' role in influencing planning through Strategic Environmental Assessment (SEA) especially related to Chinese experiences. From the perspective of planning and decision-making theory, the influence on planning is studied as influence of planning structure and influence of planning actors. Such a conceptual framework is applied in order to demonstrate how the use of indicators can influence planning through a SEA process. The study holds two empirical levels. On a general level, based on an online survey, this article investigates SEA practitioners' experiences in using indicators. On a case level, two urban plans are selected to provide more detailed experiences. The case level investigation is based on a documentary study and individual interviews with SEA practitioners/planners. By exploring how indicators influence planning through the structure of and the actors within SEA, this study tries to provide an overview of indicators' role in SEA. The results indicate that indicators are perceived as a useful tool in the Chinese SEA system. By improving and simplifying the procedures of SEA, the indicators exert more structural influence on SEA and on plan making. On the other hand, indicators are also shown to have more influence through political actors than found among technical actors. Copyright © 2017. Published by Elsevier B.V.

Regional sea level projections with observed gauge, altimeter and reconstructed data along China coast

NASA Astrophysics Data System (ADS)

Du, L.; Shi, H.; Zhang, S.

2017-12-01

Acting as the typical shelf seas in northwest Pacific Ocean, regional sea level along China coasts exhibits complicated and multiscale spatial-temporal characteristics under circumstance of global change. In this paper, sea level variability is investigated with tide gauges records, satellite altimetry data, reconstructed sea surface height, and CMIP simulation fields. Sea level exhibits the interannual variability imposing on a remarkable sea level rising in the China seas and coastal region, although its seasonal signals are significant as the results of global ocean. Sea level exhibits faster rising rate during the satellite altimetry era, nearly twice to the rate during the last sixty years. AVISO data and reconstructed sea surface heights illustrate good correlation coefficient, more than 0.8. Interannual sea level variation is mainly modulated by the low-frequency variability of wind fields over northern Pacific Ocean by local and remote processes. Meanwhile sea level varies obviously by the transport fluctuation and bimodality path of Kuroshio. Its variability possibly linked to internal variability of the ocean-atmosphere system influenced by ENSO oscillation. China Sea level have been rising during the 20th century, and are projected to continue to rise during this century. Sea level can reach the highest extreme level in latter half of 21st century. Modeled sea level including regional sea level projection combined with the IPCC climate scenarios play a significant role on coastal storm surge evolution. The vulnerable regions along the ECS coast will suffer from the increasing storm damage with sea level variations.

Changing Sea Levels

NASA Astrophysics Data System (ADS)

Pugh, David

2004-04-01

Flooding of coastal communities is one of the major causes of environmental disasters world-wide. This textbook explains how sea levels are affected by astronomical tides, weather effects, ocean circulation and climate trends. Based on courses taught by the author in the U.K. and the U.S., it is aimed at undergraduate students at all levels, with non-basic mathematics being confined to Appendices and a website http://publishing.cambridge.org/resources/0521532183/.

Extreme Storm Surges in the North Sea

NASA Astrophysics Data System (ADS)

Goennert, G.; Buß, Th.; Mueller, O.; Thumm, S.

2009-04-01

Extreme Storm Surges in the North Sea Gabriele Gönnert, Olaf Müller, Thomas Buß and Sigrid Thumm Climate Change will cause a rise of the sea level and probably more frequent and more violent storm surges. This has serious consequences for the safety of people as well as for their values and assets behind the dikes. It is therefore inevitable to first assess how sea level rise and an extreme storm surge event designes. In a second step it is possible to determine the risk for specific locations and develop strategies. The Project XtremRisk - Extreme Storm Surges at the North Sea Coast and in Estuaries. Risk calculation and risk strategies, funded by the German Federal Government will help answering these questions. The „Source-Pathway-Receptor" Concept will be used as a basis for risk analysis and development of new strategies. The Project offers methods to assess the development of extreme events under the conditions of today. Under conditions reflecting the climate change it will be tried to design an extreme event. For these three main points will be considered: a) Analysis and calculation of each factor, which produce a storm surge and its maximum level occurring in the last 100 years. These are: - maximum surge level: surge (due to the wind), - influence of the tide and the interaction between surge and tide, - influence of external surges , b) The hydrodynamics of a storm surge cause nonlinear effects in the interaction of the named factors. These factors and effects will both be taken into account to calculate the magnitude of the extreme storm surge. This step is very complex and need additional examination by numerical models. c) Analysis of the different scenarios to mean sea level rise and to the increase of wind speed due to the climate change. The presentation will introduce methods and show first results of the analysis of extreme events and the mean sea level rise.

The dynamic effects of sea level rise on low-gradient coastal landscapes: A review

USGS Publications Warehouse

Passeri, Davina L.; Hagen, Scott C.; Medeiros, Stephen C.; Bilskie, Matthew V.; Alizad, Karim; Wang, Dingbao

2015-01-01

Coastal responses to sea level rise (SLR) include inundation of wetlands, increased shoreline erosion, and increased flooding during storm events. Hydrodynamic parameters such as tidal ranges, tidal prisms, tidal asymmetries, increased flooding depths and inundation extents during storm events respond nonadditively to SLR. Coastal morphology continually adapts toward equilibrium as sea levels rise, inducing changes in the landscape. Marshes may struggle to keep pace with SLR and rely on sediment accumulation and the availability of suitable uplands for migration. Whether hydrodynamic, morphologic, or ecologic, the impacts of SLR are interrelated. To plan for changes under future sea levels, coastal managers need information and data regarding the potential effects of SLR to make informed decisions for managing human and natural communities. This review examines previous studies that have accounted for the dynamic, nonlinear responses of hydrodynamics, coastal morphology, and marsh ecology to SLR by implementing more complex approaches rather than the simplistic “bathtub” approach. These studies provide an improved understanding of the dynamic effects of SLR on coastal environments and contribute to an overall paradigm shift in how coastal scientists and engineers approach modeling the effects of SLR, transitioning away from implementing the “bathtub” approach. However, it is recommended that future studies implement a synergetic approach that integrates the dynamic interactions between physical and ecological environments to better predict the impacts of SLR on coastal systems.

Parcel-scale urban coastal flood mapping: Leveraging the multi-scale CoSMoS model for coastal flood forecasting

NASA Astrophysics Data System (ADS)

Gallien, T.; Barnard, P. L.; Sanders, B. F.

2011-12-01

California coastal sea levels are projected to rise 1-1.4 meters in the next century and evidence suggests mean tidal range, and consequently, mean high water (MHW) is increasing along portions of Southern California Bight. Furthermore, emerging research indicates wind stress patterns associated with the Pacific Decadal Oscillation (PDO) have suppressed sea level rise rates along the West Coast since 1980, and a reversal in this pattern would result in the resumption of regional sea level rise rates equivalent to or exceeding global mean sea level rise rates, thereby enhancing coastal flooding. Newport Beach is a highly developed, densely populated lowland along the Southern California coast currently subject to episodic flooding from coincident high tides and waves, and the frequency and intensity of flooding is expected to increase with projected future sea levels. Adaptation to elevated sea levels will require flood mapping and forecasting tools that are sensitive to the dominant factors affecting flooding including extreme high tides, waves and flood control infrastructure. Considerable effort has been focused on the development of nowcast and forecast systems including Scripps Institute of Oceanography's Coastal Data Information Program (CDIP) and the USGS Multi-hazard model, the Southern California Coastal Storm Modeling System (CoSMoS). However, fine scale local embayment dynamics and overtopping flows are needed to map unsteady flooding effects in coastal lowlands protected by dunes, levees and seawalls. Here, a recently developed two dimensional Godunov non-linear shallow water solver is coupled to water level and wave forecasts from the CoSMoS model to investigate the roles of tides, waves, sea level changes and flood control infrastructure in accurate flood mapping and forecasting. The results of this study highlight the important roles of topographic data, embayment hydrodynamics, water level uncertainties and critical flood processes required for meaningful prediction of sea level rise impacts and coastal flood forecasting.

Increased Flooding Risk - Accelerating Threat and Stakeholder Response

NASA Astrophysics Data System (ADS)

Atkinson, L. P.; Ezer, T.; De Young, R.; McShane, M. K.; McFarlane, B.

2012-12-01

Coastal cities have been adapting to coastal flooding for centuries. Now, with increased population along the coast combined with increased flooding because of sea level rise (SLR) the vulnerability of coastal cities has increased significantly. In this paper we will discuss the physical threat of accelerating sea level rise and the response of stakeholders. Sallenger et al (2012) stated "... we present evidence of recently accelerated SLR in a unique 1,000-km-long hotspot on the highly populated North American Atlantic coast north of Cape Hatteras and show that it is consistent with a modeled fingerprint of dynamic SLR." In the Northeast Hotspot (NEH) dynamic processes such as Gulf Stream transport can cause local sea level differences (Ezer, 2001). Sweet et al (2009) attributed the anomalously high sea level along the mid-Atlantic in 2009 to dynamic SLR. A recent paper (Ezer and Corlett, 2012 submitted), focused on Chesapeake Bay, confirms Sallenger et al. These accelerations suggest that the higher estimates of SLR in IPCC reports may be better estimates. The combination of local sea level rise and acceleration, even with average coastal storm surge, results in increased vulnerability and economic losses. We will use three examples of stakeholder response to this threat: shipbuilding, cities and insurance. Nuclear aircraft carrier drydock in Newport News, VA - The only drydock where nuclear powered aircraft carriers are built flooded during Hurricane Isabel. A study showed that with a 1 meter sea level rise and no change in storm severity they would have 'Major Flooding' every 4 months rather than every 27 years. Cities infrastructure - In a recent report on sea level rise, the Hampton Roads Planning District Commission (representing nearly 2m people) found that "sea level rise will be a major issue", "there is not yet official state or federal guidance for addressing sea level rise", "…the "…U.S. Army Corps of Engineers has developed guidance…" for their projects, and "…subsidence …. is not well-documented". Studies sponsored by the City of Norfolk for example suggest massive tidal barriers. Flood insurance - Flood insurance is available only from the National Flood Insurance Program (NFIP), not from private insurers. NFIP has a current deficit of about 18B, which is estimated to increase by about 2B annually. The rates are subsidized and do not reflect the true risk of coastal flooding and do not incorporate the likelihood of future sea-level rise. In effect, the subsidy promotes increased building on the coast, leading to increased deficits in the tax-payer financed program. Risk-based flood insurance pricing would lead to less coastal development, therefore decreasing the tax base of the community. Stakeholder needs - Planning for increased flooding due to sea level rise extends 50 to 100 years given the lifetime of infrastructure. Planners need guidance and error estimates. To make adequate predictions for users we must understand the various components of sea level rise including subsidence, global sea level rise and regional and local dynamic sea level rise. Predictions of regional sea level rise will be presented in the context of existing infrastructure such as NASA research facilities and the city of Norfolk, Virginia.

The Holocene palaeogeography and relative sea level for two tidal basins of the German North Sea coast

NASA Astrophysics Data System (ADS)

Bungenstock, Friederike; Wartenberg, Wolfram; Mauz, Barbara; Freund, Holger; Frechen, Manfred; Weerts, Henk J. T.; Berner, Heinrich

2014-05-01

The response of coasts to global sea-level rise is highly variable. Knowledge of driving coastal parameters alongside the regional sea-level history is therefore indispensable when the response to global sea-level rise is to be assessed. Here, we study the Holocene relative sea-level of the south coast of the North Sea which is controlled by a number of very local parameters, as well as by regional glacio-isostatic adjustments. It is therefore crucial to restrict the data acquisition and evaluation to small coastal sections, ideally to single tidal basins, to minimize the sources of uncertainties (Bungenstock & Weerts 2010, 2012). We present data from two tidal basins, Langeoog and Jade Bay. For Langeoog a database derived from 600 cores, 68 km of Boomer seismic data, 33 radiocarbon ages and 8 OSL dates is available. (Bungenstock & Schäfer 2009, Mauz & Bungenstock 2007). For the Jade bay, the database comprises sedimentary markers, pollen and macro remains derived from 68 cores. The sedentary chronology is based on 54 radiocarbon ages and pollen constraints (Wartenberg & Freund 2011, Wartenberg et al. 2013). For both tidal basins the sedimentological record was interpreted in terms of the local paleogeographical development since about 7000 cal BP and its influence on the local relative sea-level curve. While the trend of the relative sea level is similar for both tidal basins, it shows a different altitude. The timing of the main marine transgression within the Langeoog area takes place ~3000 cal. BP whereas the sedimentological record of the Jade Bay shows two prominent transgressions, one for ~5000 cal. BP and one for ~3000 cal. BP. The Langeoog palaeo-environment is continuously characterised by marine influence. Within the Jade Bay two different palaeo-environments could be identified, documenting that from the West to the centre the landscape development in the Jade Bay was drainage driven feeding the associated fen peat with minerogenic water but being autonomous from isochronic relative sea-level. This all shows the importance to understand the differences of local landscape and depositional developments for a reliable interpretation of sea-level data. References Bungenstock, F. & Schäfer, A. (2009): The Holocene relative sea-level curve for the tidal basin of the barrier island Langeoog, German Bight, Southern North Sea. - Global and Planetary Change 66: 34-51. Bungenstock, F. & Weerts, H.J.T. (2011): The high-resolution Holocene sea-level curve for Nothwest Germany: global signals, local effects or data-artefacts? - International Journal of Earth Sciences 99: 1687-1706. Bungenstock, F. & Weerts, H.J.T. (2012): Holocene relative sea-level curves for the German North Sea coast. International Journal of Earth Sciences. ? - International Journal of Earth Sciences 101:1083-1099. Mauz, B. & Bungenstock, F. (2007):. How to reconstruct trends of late Holocene relative sea level: A new approach using tidal flat clastic sediments and optical dating. Marine Geology 237: 225-237. Wartenberg, W. & Freund, H. (2011): Late Pleistocene and Holocene sedimentary record within the Jade Bay, Lower Saxony, Northwest Germany - New aspects for the palaeoecological record. - Quaternary International:1-11. Wartenberg, W., Vött, A., Freund, H. Hadler, H., Frechen, M., Willershäuser, T., Schnaidt, S., Fischer, P. & Obrocki, L. (2013): Evidence of isochronic transgressive surfaces within the Jade Bay tidal flfl at area, southern German North Sea coast - Holocene event horizons of regional interest. - Zeitschrift für Geomorphologi, Supplementary Issue. DOI: 10.1127/0372-8854/2013/S-00150

Understanding the Effects of Sea-Level Rise on Coastal Wetlands: The Human Dimension

NASA Astrophysics Data System (ADS)

Reed, Denise

2010-05-01

In the 21st century coastal systems are subject to the pressures of centuries of population growth and resource exploitation. In 2003, in the US approximately 153 million people (53 percent of the population) lived in coastal counties, an increase of 33 million people since 1980 and this is expected to increase by approximately 7 million by the year 2008. Eight of the world's top ten largest cities are located at the coast, 44 % of the world's population (more people than inhabited the entire globe in 1950) live within 150 km of the coast and in 2001 over half the world's population lived within 200 km of a coastline. . Increased population density at the coasts often brings pollution and habitat degradation - decreasing the value of many of the resources that initially attract the coastal development - and it also means the effect of sea-level rise on coastal geomorphic systems must be seen in the context of additional human pressures. For global sea-level debate centers on the magnitude and rate of the rise around most of the world; the exception being those areas still experiencing falling sea-levels due to isostatic rebound. Many coastal island states are clearly vulnerable. While the ‘lurid and misleading maps' of the 1980's used by many to indicate areas to be flooded by rising seas in the future, have been replaced by more considered discussion of the response of coastal dynamics to rising seas there is still considerable debate about the amount of sea-level rise shorelines will experience in the 21st century. For coastal wetlands four main sets of physical factors - fine sediment regime; tidal conditions; coastal configuration; and relative sea-level change - define the geomorphic context for coastal marsh development and survival during the 21st century. Each of these factors is influenced by changes in climate and human alterations to coastal and inshore environments. In turn changes in sediment dynamics are mediated by both physical forcing and biotic factors, and plant growth is an additional factor influencing the survival of more organic marshes. Salt marsh surfaces are frequently considered to be in an equilibrium relationship with local mean sea level but the projection of salt marsh sustainability under future climate scenarios is a complex issue and depends on: the relative importance of organic matter to marsh vertical development; the complexities governing organic matter accumulation during rising sea level; the importance of subsurface processes in determining surface elevation change; and the role of storm events and hydrologic changes in controlling sediment deposition, soil conditions and plant growth. The effects of global change, both climate and human induced, on coastal wetlands will be manifest differently among various geomorphic settings but their vulnerability to global change in the 21st century should be taken seriously by coastal managers and policy-makers alike.

Investigation on the antidepressant effect of sea buckthorn seed oil through the GC-MS-based metabolomics approach coupled with multivariate analysis.

PubMed

Tian, Jun-sheng; Liu, Cai-chun; Xiang, Huan; Zheng, Xiao-fen; Peng, Guo-jiang; Zhang, Xiang; Du, Guan-hua; Qin, Xue-mei

2015-11-01

Depression is one of the prevalent and serious mental disorders and the number of depressed patients has been on the rise globally during the recent decades. Sea buckthorn seed oil from traditional Chinese medicine (TCM) is edible and has been widely used for treatment of different diseases for a long time. However, there are few published reports on the antidepressant effect of sea buckthorn seed oil. With the objective of finding potential biomarkers of the therapeutic response of sea buckthorn seed oil in chronic unpredictable mild stress (CUMS) rats, urine metabolomics based on gas chromatography-mass spectrometry (GC-MS) coupled with multivariate analysis was applied. In this study, we discovered a higher level of pimelic acid as well as palmitic acid and a lower level of suberic acid, citrate, phthalic acid, cinnamic acid and Sumiki's acid in urine of rats exposed to CUMS procedures after sea buckthorn seed oil was administered. These changes of metabolites are involved in energy metabolism, fatty acid metabolism and other metabolic pathways as well as in the synthesis of neurotransmitters and it is helpful to facilitate the efficacy evaluation and mechanism elucidating the effect of sea buckthorn seed oil for depression management.

Correlation of sea level falls interpreted from atoll stratigraphy with turbidites in adjacent basins

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lincoln, J.M.

Past sea levels can be derived from any atoll subsurface sediments deposited at or near sea level by determining the ages of deposition and correcting the present depths to the sediments for subsidence of the underlying edifice since the times of deposition. A sea level curve constructed by this method consists of discontinuous segments, each corresponding to a period of rising relative sea level and deposition of a discrete sedimentary package. Discontinuities in the sea level curve derived by this method correspond to relative sea level falls and stratigraphic hiatuses in the atoll subsurface. During intervals of relative sea levelmore » fall an atoll emerges to become a high limestone island. Sea level may fluctuate several times during a period of atoll emergence to become a high limestone island. Sea level may fluctuate several times during a period of atoll emergence without depositing sediments on top of the atoll. Furthermore, subaerial erosion may remove a substantial part of the depositional record of previous sea level fluctuations. For these reasons the authors must look to the adjacent basins to complement the incomplete record of sea level change recorded beneath atolls. During lowstands of sea level, faunas originally deposited near sea level on an atoll may be eroded and redeposited as turbidites in deep adjacent basins. Three such turbidites penetrated during deep-sea drilling at Sites 462 and 315 in the central Pacific correlate well with a late Tertiary sea level curve based on biostratigraphic ages and {sup 87}Sr/{sup 86}Sr chronostratigraphy for core from Enewetak Atoll in the northern Marshall Islands. Further drilling of the archipelagic aprons adjacent to atolls will improve the sea level history that may be inferred from atoll stratigraphy.« less

Brief communication: The global signature of post-1900 land ice wastage on vertical land motion

NASA Astrophysics Data System (ADS)

Riva, Riccardo E. M.; Frederikse, Thomas; King, Matt A.; Marzeion, Ben; van den Broeke, Michiel R.

2017-06-01

Melting glaciers, ice caps and ice sheets have made an important contribution to sea-level rise through the last century. Self-attraction and loading effects driven by shrinking ice masses cause a spatially varying redistribution of ocean waters that affects reconstructions of past sea level from sparse observations. We model the solid-earth response to ice mass changes and find significant vertical deformation signals over large continental areas. We show how deformation rates have been strongly varying through the last century, which implies that they should be properly modelled before interpreting and extrapolating recent observations of vertical land motion and sea-level change.

Sedimentary, tectonic, and sea-level controls on submarine fan and slope-apron turbidite systems

USGS Publications Warehouse

Stow, D.A.V.; Howell, D.G.; Nelson, C.H.

1984-01-01

To help understand factors that influence submarine fan deposition, we outline some of the principal sedimentary, tectonic, and sea-level controls involved in deep-water sedimentation, give some data on the rates at which they operate, and evaluate their probable effects. Three depositional end-member systems, two submarine fan types (elongate and radial), and a third nonfan, slope-apron system result primarily from variations in sediment type and supply. Tectonic setting and local and global sea-level changes further modify the nature of fan growth, the distribution of facies, and the resulting vertical stratigraphic sequences. ?? 1984 Springer-Verlag New York Inc.

Assessment of total and organic vanadium levels and their bioaccumulation in edible sea cucumbers: tissues distribution, inter-species-specific, locational differences and seasonal variations.

PubMed

Liu, Yanjun; Zhou, Qingxin; Xu, Jie; Xue, Yong; Liu, Xiaofang; Wang, Jingfeng; Xue, Changhu

2016-02-01

The objective of this study is to investigate the levels, inter-species-specific, locational differences and seasonal variations of vanadium in sea cucumbers and to validate further several potential factors controlling the distribution of metals in sea cucumbers. Vanadium levels were evaluated in samples of edible sea cucumbers and were demonstrated exhibit differences in different seasons, species and sampling sites. High vanadium concentrations were measured in the sea cucumbers, and all of the vanadium detected was in an organic form. Mean vanadium concentrations were considerably higher in the blood (sea cucumber) than in the other studied tissues. The highest concentration of vanadium (2.56 μg g(-1)), as well as a higher degree of organic vanadium (85.5 %), was observed in the Holothuria scabra samples compared with all other samples. Vanadium levels in Apostichopus japonicus from Bohai Bay and Yellow Sea have marked seasonal variations. Average values of 1.09 μg g(-1) of total vanadium and 0.79 μg g(-1) of organic vanadium were obtained in various species of sea cucumbers. Significant positive correlations between vanadium in the seawater and V org in the sea cucumber (r = 81.67 %, p = 0.00), as well as between vanadium in the sediment and V org in the sea cucumber (r = 77.98 %, p = 0.00), were observed. Vanadium concentrations depend on the seasons (salinity, temperature), species, sampling sites and seawater environment (seawater, sediment). Given the adverse toxicological effects of inorganic vanadium and positive roles in controlling the development of diabetes in humans, a regular monitoring programme of vanadium content in edible sea cucumbers can be recommended.

Forecasting consequences of changing sea ice availability for Pacific walruses

USGS Publications Warehouse

Udevitz, Mark S.; Jay, Chadwick V.; Taylor, Rebecca; Fischbach, Anthony S.; Beatty, William S.; Noren, Shawn R.

2017-01-01

The accelerating rate of anthropogenic alteration and disturbance of environments has increased the need for forecasting effects of environmental change on fish and wildlife populations. Models linking projections of environmental change with behavioral responses and bioenergetic effects can provide a basis for these forecasts. There is particular interest in forecasting effects of projected reductions in sea ice availability on Pacific walruses (Odobenus rosmarus divergens). Declining extent of summer sea ice in the Chukchi Sea has caused Pacific walruses to increase use of coastal haulouts and decrease use of more productive offshore feeding areas. Such climate-induced changes in distribution and behavior could ultimately affect the status of the population. We developed behavioral models to relate changes in sea ice availability to adult female walrus movements and activity levels, and adapted previously developed bioenergetics models to relate those activity levels to energy requirements and the ability to meet those requirements. We then linked these models to general circulation model projections of future ice availability to forecast autumn body condition for female walruses during mid- and late-century time periods. Our results suggest that as sea ice becomes less available in the Chukchi Sea, female walruses will spend more time in the southwestern region of that sea, less time resting, and less time foraging. Median forecasted autumn body masses were 7–12% lower in future scenarios than during recent times, but posterior distributions broadly overlapped and median forecasted seasonal mass losses (15–34%) were comparable to seasonal mass losses routinely experienced by other pinnipeds. These seasonal reductions in body condition would be unlikely to result in demographic effects, but if walruses were unable to rebuild endogenous reserves while wintering in the Bering Sea, cumulative effects could have implications for reproduction and survival, ultimately affecting the status of the Pacific walrus population. Our approach provides a general framework for forecasting consequences of the broad range of environmental changes and anthropogenic disturbances that may affect bioenergetics through behavioral responses or changes in prey availability.

Sea-Level Rise and Flood Potential along the California Coast

NASA Astrophysics Data System (ADS)

Delepine, Q.; Leung, C.

2013-12-01

Sea-level rise is becoming an ever-increasing problem in California. Sea-level is expected to rise significantly in the next 100 years, which will raise flood elevations in coastal communities. This will be an issue for private homeowners, businesses, and the state. One study suggests that Venice Beach could lose a total of at least $440 million in tourism spending and tax dollars from flooding and beach erosion if sea level rises 1.4 m by 2100. In addition, several airports, such as San Francisco International Airport, are located in coastal regions that have flooded in the past and will likely be flooded again in the next 30 years, but sea-level rise is expected to worsen the effects of flooding in the coming decades It is vital for coastal communities to understand the risks associated with sea-level rise so that they can plan to adapt to it. By obtaining accurate LiDAR elevation data from the NOAA Digital Coast Website (http://csc.noaa.gov/dataviewer/?keyword=lidar#), we can create flood maps to simulate sea level rise and flooding. The data are uploaded to ArcGIS and contour lines are added for different elevations that represent future coastlines during 100-year flooding. The following variables are used to create the maps: 1. High-resolution land surface elevation data - obtained from NOAA 2. Local mean high water level - from USGS 3. Local 100-year flood water level - from the Pacific Institute 4. Sea-level rise projections for different future dates (2030, 2050, and 2100) - from the National Research Council The values from the last three categories are added to represent sea-level rise plus 100-year flooding. These values are used to make the contour lines that represent the projected flood elevations, which are then exported as KML files, which can be opened in Google Earth. Once these KML files are made available to the public, coastal communities will gain an improved understanding of how flooding and sea-level rise might affect them in the future. This would allow them to plan ahead to reduce the level of risk to homes, industry, and infrastructure San Francisco International Airport will be most likely be flooded in the next 30 years. Blue lines indicate current Mean High Water Levels. Yellow lines indicate the Mean High Water level combined with flood levels for 2030. Green, 2050, and Red lines, 2100

Long river profiles, tectonism, and eustasy: A guide to interpreting fluvial terraces

NASA Technical Reports Server (NTRS)

Merritts, Dorothy J.; Vincent, Kirk R.; Wohl, Ellen E.

1994-01-01

Along three rivers at the Mendocino triple junction, northern California, strath, cut, and fill terraces have formed in response to tectonic and eustatic processes. Detailed surveying and radiometric dating at multiple sites indicate that lower reaches of the rivers are dominated by the effects of oscillating sea level, primarily aggradation and formation of fill terraces during sea level high stands, alternating with deep incision during low stands. A eustasy-driven depositional wedge extends tens of kilometers upstream on all rivers (tapering to zero thickness). This distance is greater than expected from studies of the effects of check dams on much smaller streams elsewhere, due in part to the large size of these rivers. However, the change in gradient is nearly identical to other base level rise studies: the depositional gradient is about half that of the original channel. Middle to upper reaches of each river are dominated by the effects of long-term uplift, primarily lateral and vertical erosion and formation of steep, unpaired strath terraces exposed only upstream of the depositional wedge. Vertical incision at a rate similar to that of uplift has occurred even during the present sea level high stand along rivers with highest uplift rates. Strath terraces have steeper gradients than the modern channel bed and do not merge with marine terraces at the river mouth; consequently, they cannot be used to determine altitudes of sea level high stands. Strath formation is a continuous process of response to long-term uplift, and its occurrence varies spatially along a river depending on stream power, and hence position, upstream. Strath terraces are found only along certain parts of a coastal stream: upstream of the aggradational effects of oscillating sea level, and far enough downstream that stream power is in excess of that needed to transport the prevailing sediment load. For a given size river, the greater the uplift rate, the greater the rate of vertical incision and, consequently, the less the likelihood of strath terrace formation and preservation.

Relative Sea Level Trends Along the Coast of the Bay of Bengal

NASA Astrophysics Data System (ADS)

Becker, M.; Calmant, S.; Papa, F.; Delebecque, C.; Islam, A. S.; Shum, C. K.

2016-12-01

In the coastal belt of the Bay of Bengal, the sea level rise is one of a major threat, linked to climate change, which drastically affects the livelihoods of millions of people. A comprehensive understanding of sea level trends and its variability in this region is therefore crucial and should help to anticipate the impacts of climate change and implement adaptation strategies. This region is bordered mostly by Bangladesh, India, Malaysia, Myanmar, and Thailand. Here, we revisit the sea level changes in the Bay of Bengal region from tide gauges and satellite altimetry over the period 1993-2014. The 23 monthly mean tide gauge records, used in this study, are retrieved from PSMSL (15 records) and supplemented with Bangladeshi observations (8 records). We show that, over the satellite altimetry era, the sea level interannual/decadal variability is mainly due to ocean thermal expansion variability driven by IOD/ENSO events and their low frequency modulation. We focus on relative sea level rise at major coastal cities and try to separate the climatic signal (long term trend plus interannual/decadal variability) from local effects, in particular vertical land movements. Results from GPS are analysed where available. When no such data exist, vertical land movements are deduced from the combined use of tide gauge and altimetry data. While the analysis is performed over the whole region, a particular attention is given to the low-lyingBangladesh's coastal area.

Temporal response of hydraulic head, temperature, and chloride concentrations to sea-level changes, Floridan aquifer system, USA

USGS Publications Warehouse

Hughes, J.D.; Vacher, H. Leonard; Sanford, W.E.

2009-01-01

Three-dimensional density-dependent flow and transport modeling of the Floridan aquifer system, USA shows that current chloride concentrations are not in equilibrium with current sea level and, second, that the geometric configuration of the aquifer has a significant effect on system responses. The modeling shows that hydraulic head equilibrates first, followed by temperatures, and then by chloride concentrations. The model was constructed using a modified version of SUTRA capable of simulating multi-species heat and solute transport, and was compared to pre-development conditions using hydraulic heads, chloride concentrations, and temperatures from 315 observation wells. Three hypothetical, sinusoidal sea-level changes occurring over 100,000 years were used to evaluate how the simulated aquifer responds to sea-level changes. Model results show that hydraulic head responses lag behind sea-level changes only where the Miocene Hawthorn confining unit is thick and represents a significant restriction to flow. Temperatures equilibrate quickly except where the Hawthorn confining unit is thick and the duration of the sea-level event is long (exceeding 30,000 years). Response times for chloride concentrations to equilibrate are shortest near the coastline and where the aquifer is unconfined; in contrast, chloride concentrations do not change significantly over the 100,000-year simulation period where the Hawthorn confining unit is thick. ?? US Government 2008.

Wetland Responses to Sea Level Rise in the Northern Gulf of Mexico

NASA Astrophysics Data System (ADS)

Alizad, K.; Bilskie, M. V.; Hagen, S. C.; Medeiros, S. C.; Morris, J. T.

2016-12-01

Coastal regions are vulnerable to flood risk due to climate change, sea level rise, and wetland losses. The Northern Gulf of Mexico (NGOM) is a region in which extreme events are projected to be more intense under climate change and sea level rise scenarios [Wang et al., 2013; Bilskie et al., 2014]. Considering increased frequency and intensity of coastal flooding, wetlands are valuable natural resources that protect shorelines by dissipating waves and storm surges [Costanza et al., 2008]. Therefore, it is critical to investigate the response of salt marsh systems in different estuaries to sea level rise in the NGOM and their effects on storm surges to inform coastal managers to choose effective restoration plans. This research applies the coupled Hydro-MEM model [Alizad et al., 2016] to study three different estuarine systems in the NGOM. The model incorporates both sea level rise rate and feedbacks between physics and biology by coupling a hydrodynamic (ADCIRC) and salt marsh (MEM) model. The results of the model provide tidal hydrodynamics and biomass density change under four sea level rise projections during a 100-year period. The results are used to investigate marsh migration path in the estuarine systems. In addition, this study shows how marsh migration and biomass density change can impact storm surge modeling. The results imply the broader impacts of sea level rise on the estuarine systems in the NGOM. ReferencesAlizad, K., S. C. Hagen, J. T. Morris, P. Bacopoulos, M. V. Bilskie, J. Weishampel, and S. C. Medeiros (2016), A coupled, two-dimensional hydrodynamic-marsh model with biological feedback, Ecological Modeling, 327, 29-43. Bilskie, M. V., S. C. Hagen, S. C. Medeiros, and D. L. Passeri (2014), Dynamics of sea level rise and coastal flooding on a changing landscape, Geophysical Research Letters, 41(3), 927-934. Costanza, R., O. Pérez-Maqueo, M. L. Martinez, P. Sutton, S. J. Anderson, and K. Mulder (2008), The Value of Coastal Wetlands for Hurricane Protection, AMBIO: A Journal of the Human Environment, 37(4). Wang, D., S. C. Hagen, and K. Alizad (2013), Climate change impact and uncertainty analysis of extreme rainfall events in the Apalachicola River basin, Florida, Journal of Hydrology, 480(0), 125-135.

Effect of potential probiotic Rhodotorula benthica D30 on the growth performance, digestive enzyme activity and immunity in juvenile sea cucumber Apostichopus japonicus.

PubMed

Wang, Ji-hui; Zhao, Liu-qun; Liu, Jin-feng; Wang, Han; Xiao, Shan

2015-04-01

The effects of dietary addition of yeast Rhodotorula benthica (R. benthica) D30 which isolated from local sea mud at levels of 0 (control), 10(5), 10(6) and 10(7) CFU/g feed on the growth performance, digestive enzyme activity, immunity and disease resistance of juvenile sea cucumber Apostichopus japonicus were investigated. It was shown that dietary addition of R. benthica D30 significantly increased the growth rates of sea cucumbers (p < 0.05). The amylase activity, cellulase activity and alginase activity were increased for the animals from three probiotics treated groups. And with the supplemented concentration increased, the values of those digestive enzyme activities increased as well. Dietary addition of R. benthica D30 at the level of 10(7) CFU significantly increased the lysozyme, phagocytic and total nitric oxide synthase activity of A. japonicus (p < 0.05). While, the highest values of the phenoloxidase and alkaline phosphatase activity were found in sea cucumbers fed with R. benthica D30 at the level of 10(6) CFU. Whereas adding R. benthica D30 to diet had no significant effects on the total coelomocyte counts and acid phosphatase activity of A. japonicus (p > 0.05). It was observed that adding R. benthica D30 could significantly decrease the cumulative mortality of sea cucumbers. The present study demonstrated that dietary addition of R. benthica D30 could increase growth performance and some digestive enzyme activities, improve immunity and disease resistance of A. japonicus. And the medium (10(6) CFU) and high (10(7) CFU) additional levels showed better effects. It suggests that yeast R. benthica D30 could be a good probiotic for aquaculture. Copyright © 2015 Elsevier Ltd. All rights reserved.

Decadal-timescale estuarine geomorphic change under future scenarios of climate and sediment supply

USGS Publications Warehouse

Ganju, N.K.; Schoellhamer, D.H.

2010-01-01

Future estuarine geomorphic change, in response to climate change, sea-level rise, and watershed sediment supply, may govern ecological function, navigation, and water quality. We estimated geomorphic changes in Suisun Bay, CA, under four scenarios using a tidal-timescale hydrodynamic/sediment transport model. Computational expense and data needs were reduced using the morphological hydrograph concept and the morphological acceleration factor. The four scenarios included (1) present-day conditions; (2) sea-level rise and freshwater flow changes of 2030; (3) sea-level rise and decreased watershed sediment supply of 2030; and (4) sea-level rise, freshwater flow changes, and decreased watershed sediment supply of 2030. Sea-level rise increased water levels thereby reducing wave-induced bottom shear stress and sediment redistribution during the wind-wave season. Decreased watershed sediment supply reduced net deposition within the estuary, while minor changes in freshwater flow timing and magnitude induced the smallest overall effect. In all future scenarios, net deposition in the entire estuary and in the shallowest areas did not keep pace with sea-level rise, suggesting that intertidal and wetland areas may struggle to maintain elevation. Tidal-timescale simulations using future conditions were also used to infer changes in optical depth: though sea-level rise acts to decrease mean light irradiance, decreased suspended-sediment concentrations increase irradiance, yielding small changes in optical depth. The modeling results also assisted with the development of a dimensionless estuarine geomorphic number representing the ratio of potential sediment import forces to sediment export forces; we found the number to be linearly related to relative geomorphic change in Suisun Bay. The methods implemented here are widely applicable to evaluating future scenarios of estuarine change over decadal timescales. ?? The Author(s) 2009.

Simulated changes in salinity in the York and Chickahominy Rivers from projected sea-level rise in Chesapeake Bay

USGS Publications Warehouse

Rice, Karen C.; Bennett, Mark; Shen, Jian

2011-01-01

As a result of climate change and variability, sea level is rising throughout the world, but the rate along the east coast of the United States is higher than the global mean rate. The U.S. Geological Survey, in cooperation with the City of Newport News, Virginia, conducted a study to evaluate the effects of possible future sea-level rise on the salinity front in two tributaries to Chesapeake Bay, the York River, and the Chickahominy/James River estuaries. Numerical modeling was used to represent sea-level rise and the resulting hydrologic effects. Estuarine models for the two tributaries were developed and model simulations were made by use of the Three-Dimensional Hydrodynamic-Eutrophication Model (HEM-3D), developed by the Virginia Institute of Marine Science. HEM-3D was used to simulate tides, tidal currents, and salinity for Chesapeake Bay, the York River and the Chickahominy/James River. The three sea-level rise scenarios that were evaluated showed an increase of 30, 50, and 100 centimeters (cm). Model results for both estuaries indicated that high freshwater river flow was effective in pushing the salinity back toward Chesapeake Bay. Model results indicated that increases in mean salinity will greatly alter the existing water-quality gradients between brackish water and freshwater. This will be particularly important for the freshwater part of the Chickahominy River, where a drinking-water-supply intake for the City of Newport News is located. Significant changes in the salinity gradients for the York River and Chickahominy/James River estuaries were predicted for the three sea-level rise scenarios. When a 50-cm sea-level rise scenario on the York River during a typical year (2005) was used, the model simulation showed a salinity of 15 parts per thousand (ppt) at river kilometer (km) 39. During a dry year (2002), the same salinity (15 ppt) was simulated at river km 45, which means that saltwater was shown to migrate 6 km farther upstream during a dry year than a typical year. The same was true of the Chickahominy River for a 50-cm sea-level rise scenario but to a greater extent; a salinity of 4 ppt was simulated at river km 13 during a typical year and at river km 28 during a dry year, indicating that saltwater migrated 15 km farther upstream during a dry year. Near a drinking-water intake on the Chickahominy River, for a dry year, salinity is predicted to more than double for all three sea-level rise scenarios, relative to a typical year. During a typical year at this location, salinity is predicted to increase to 0.006, 0.07, and more than 2 ppt for the 30-, 50-, and 100-cm rise scenarios, respectively.

δ18O and Marion Plateau backstripping: Combining two approaches to constrain late middle Miocene eustatic amplitude

NASA Astrophysics Data System (ADS)

John, Cédric M.; Karner, Garry D.; Mutti, Maria

2004-09-01

δ18Obenthic values from Leg 194 Ocean Drilling Program Sites 1192 and 1195 (drilled on the Marion Plateau) were combined with deep-sea values to reconstruct the magnitude range of the late middle Miocene sea-level fall (13.6 11.4 Ma). In parallel, an estimate for the late middle Miocene sea-level fall was calculated from the stratigraphic relationship identified during Leg 194 and the structural relief of carbonate platforms that form the Marion Plateau. Corrections for thermal subsidence induced by Late Cretaceous rifting, flexural sediment loading, and sediment compaction were taken into account. The response of the lithosphere to sediment loading was considered for a range of effective elastic thicknesses (10 < Te < 40 km). By overlapping the sea-level range of both the deep-sea isotopes and the results from the backstripping analysis, we demonstrate that the amplitude of the late middle Miocene sea-level fall was 45 68 m (56.5 ± 11.5 m). Including an estimate for sea-level variation using the δ18Obenthic results from the subtropical Marion Plateau, the range of sea-level fall is tightly constrained between 45 and 55 m (50.0 ± 5.0 m). This result is the first precise quantitative estimate for the amplitude of the late middle Miocene eustatic fall that sidesteps the errors inherent in using benthic foraminifera assemblages to predict paleo water depth. The estimate also includes an error analysis for the flexural response of the lithosphere to both water and sediment loads. Our result implies that the extent of ice buildup in the Miocene was larger than previously estimated, and conversely that the amount of cooling associated with this event was less important.

Non-Linear Interactions Determine the Impact of Sea-Level Rise on Estuarine Benthic Biodiversity and Ecosystem Processes

PubMed Central

Yamanaka, Tsuyuko; Raffaelli, David; White, Piran C. L.

2013-01-01

Sea-level rise induced by climate change may have significant impacts on the ecosystem functions and ecosystem services provided by intertidal sediment ecosystems. Accelerated sea-level rise is expected to lead to steeper beach slopes, coarser particle sizes and increased wave exposure, with consequent impacts on intertidal ecosystems. We examined the relationships between abundance, biomass, and community metabolism of benthic fauna with beach slope, particle size and exposure, using samples across a range of conditions from three different locations in the UK, to determine the significance of sediment particle size beach slope and wave exposure in affecting benthic fauna and ecosystem function in different ecological contexts. Our results show that abundance, biomass and oxygen consumption of intertidal macrofauna and meiofauna are affected significantly by interactions among sediment particle size, beach slope and wave exposure. For macrofauna on less sloping beaches, the effect of these physical constraints is mediated by the local context, although for meiofauna and for macrofauna on intermediate and steeper beaches, the effects of physical constraints dominate. Steeper beach slopes, coarser particle sizes and increased wave exposure generally result in decreases in abundance, biomass and oxygen consumption, but these relationships are complex and non-linear. Sea-level rise is likely to lead to changes in ecosystem structure with generally negative impacts on ecosystem functions and ecosystem services. However, the impacts of sea-level rise will also be affected by local ecological context, especially for less sloping beaches. PMID:23861863

Non-linear interactions determine the impact of sea-level rise on estuarine benthic biodiversity and ecosystem processes.

PubMed

Yamanaka, Tsuyuko; Raffaelli, David; White, Piran C L

2013-01-01

Sea-level rise induced by climate change may have significant impacts on the ecosystem functions and ecosystem services provided by intertidal sediment ecosystems. Accelerated sea-level rise is expected to lead to steeper beach slopes, coarser particle sizes and increased wave exposure, with consequent impacts on intertidal ecosystems. We examined the relationships between abundance, biomass, and community metabolism of benthic fauna with beach slope, particle size and exposure, using samples across a range of conditions from three different locations in the UK, to determine the significance of sediment particle size beach slope and wave exposure in affecting benthic fauna and ecosystem function in different ecological contexts. Our results show that abundance, biomass and oxygen consumption of intertidal macrofauna and meiofauna are affected significantly by interactions among sediment particle size, beach slope and wave exposure. For macrofauna on less sloping beaches, the effect of these physical constraints is mediated by the local context, although for meiofauna and for macrofauna on intermediate and steeper beaches, the effects of physical constraints dominate. Steeper beach slopes, coarser particle sizes and increased wave exposure generally result in decreases in abundance, biomass and oxygen consumption, but these relationships are complex and non-linear. Sea-level rise is likely to lead to changes in ecosystem structure with generally negative impacts on ecosystem functions and ecosystem services. However, the impacts of sea-level rise will also be affected by local ecological context, especially for less sloping beaches.

Early-mid-Cretaceous evolution in Tethyan reef communities and sea level

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scott, R.W.

1988-01-01

The replacement of corals by rudists in Early Cretaceous reefal communities spanned a 30-m.y. period when sea level rose and drowned continental shelves. During this time corals formed communities in the deeper parts of reefs and rudists occupied the shallow, high-energy habitats. By Aptian time rudists dominated reefs that fringed interior shelf basins and corals formed reefs with rudists on the outer shelf margins. By late Albian coral communities had virtually disappeared, presumably because of complex environmental changes and cycles of organic productivity. Two important events of eustatic sea level rise are represented by unconformities separating carbonate depositional sequences onmore » the Arabian platform that correlate with sequence boundaries on the Gulf Coast platform. Graphic correlation techniques test the synchroneity of these events. A composite standard time scale dates these sea level rises at 115.8 Ma and 94.6 Ma; a third, intra-Albian event at 104.3 Ma is present in many places and may also be eustatic. Associated with these sea level rises were apparent changes in ocean water chemistry as evidenced by changes in isotopes and trace elements, where diagenetic effects can be discounted. During this time the climate became more humid and atmospheric CO/sub 2/ increased. The concomitant environmental changes in the oceanic conditions presumably stressed the deeper coral communities on reefs. The emergence of rudists as reef contributors had a profound effect on Late Cretaceous depositional conditions and the development of hydrocarbon reservoirs.« less

Early-mid-Cretaceous evolution in Tethyan reef communities and sea level

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scott, R.W.

1988-02-01

The replacement of corals by rudists in Early Cretaceous reefal communities spanned a 30-m.y. period when sea level rose and drowned continental shelves. During this time corals formed communities in the deeper parts of reefs and rudists occupied the shallow, high-energy habitats. By Aptian time rudists dominated reefs that fringed interior shelf basins and corals formed reefs with rudists on the outer shelf margins. By late Albian coral communities had virtually disappeared, presumably because of complex environmental changes and cycles of organic productivity. Two important events of eustatic sea level rise are represented by unconformities separating carbonate depositional sequences onmore » the Arabian platform that correlate with sequence boundaries on the Gulf Coast platform. Graphic correlation techniques test the synchroneity of these events. A composite standard time scale dates these sea level rises at 115.8 Ma and 94.6 Ma; a third, intra-Albian event at 104.3 Ma is present in many places and may also be eustatic. Associated with these sea level rises were apparent changes in ocean water chemistry as evidenced by changes in isotopes and trace elements, where diagenetic effects can be discounted. During this time the climate became more humid and atmospheric CO/sub 2/ increased. The concomitant environmental changes in the oceanic conditions presumably stressed the deeper coral communities on reefs. The emergence of rudists as reef contributors had a profound effect on Late Cretaceous depositional conditions and the development of hydrocarbon reservoirs.« less

Increasing the highest storm surge in Busan harbor

NASA Astrophysics Data System (ADS)

Oh, Sang Myeong; Moon, Il-Ju; Kwon, Suk Jae

2017-04-01

One of the most pronounced effects of climate change in coastal regions is sea level rise and storm surges. Busan in particular, the fifth largest container handling port in the world, has suffered from serious storm surges and experienced a remarkable mean sea level (MSL) rise. This study investigates a long-term variation of annual maximum surge height (AMSH) using sea level data observed in Busan over 53 years (1962 2014). The decomposition of astronomical tides and surge components shows that the AMSH has increased 18 cm over 53 years (i.e., 3.5 mm/year), which is much larger than the MSL trend (2.5 mm/year) in Busan. This significant increase in AMSH is mostly explained by the increased intensity of landfall typhoons over the Korean peninsula (KP), which is associated with the increase of sea surface temperature and the decrease of vertical wind shear at mid-latitudes of the western North Pacific. In a projected future warming environment, the combination of an increasing MSL and AMSH will accelerate the occurrence of record-breaking extreme sea levels, which will be a potential threat in Busan harbor.

Combining Geography, Math, and Science to Teach Climate Change and Sea Level Rise

ERIC Educational Resources Information Center

Oldakowski, Ray; Johnson, Ashley

2018-01-01

This study examines the effectiveness of integrating geography into existing math and science curriculum to teach climate change and sea level rise. The desired outcome is to improve student performance in all three subjects. A sample of 120 fifth graders from three schools were taught the integrated curriculum over a period of two to three weeks.…

An ecological model of the habitat mosaic in estuarine nursery areas: Part II – Projecting effects of sea level rise on fish production

EPA Science Inventory

Understanding the response of fish populations to habitat change mediated by sea level rise (SLR) is a key component of ecosystem-based management. Yet, no direct link has been established between habitat change due to SLR and fish population production. Here we take a coupled ...

Examining the potential for nutritional stress in young Steller sea lions: physiological effects of prey composition.

PubMed

Rosen, David A S; Trites, Andrew W

2005-05-01

The effects of high- and low-lipid prey on the body mass, body condition, and metabolic rates of young captive Steller sea lions (Eumetopias jubatus) were examined to better understand how changes in prey composition might impact the physiology and health of wild sea lions and contribute to their population decline. Results of three feeding experiments suggest that prey lipid content did not significantly affect body mass or relative body condition (lipid mass as a percent of total mass) when sea lions could consume sufficient prey to meet their energy needs. However, when energy intake was insufficient to meet daily requirements, sea lions lost more lipid mass (9.16+/-1.80 kg+/-SE) consuming low-lipid prey compared with eating high-lipid prey (6.52+/-1.65 kg). Similarly, the sea lions lost 2.7+/-0.9 kg of lipid mass while consuming oil-supplemented pollock at maintenance energy levels but gained 5.2+/-2.7 kg lipid mass while consuming identical energetic levels of herring. Contrary to expectations, there was a 9.7+/-1.8% increase in metabolism during mass loss on submaintenance diets. Relative body condition decreased only 3.7+/-3.8% during periods of imposed nutritional stress, despite a 10.4+/-4.8% decrease in body mass. These findings raise questions regarding the efficacy of measures of relative body condition to detect such changes in nutritional status among wild animals. The results of these three experiments suggest that prey composition can have additional effects on sea lion energy stores beyond the direct effects of insufficient energy intake.

Parental Effect of Long Acclimatization on Thermal Tolerance of Juvenile Sea Cucumber Apostichopus japonicus

PubMed Central

Dong, Yun-wei

2015-01-01

To evaluate the thermal resistance of marine invertebrates to elevated temperatures under scenarios of future climate change, it is crucial to understand parental effect of long acclimatization on thermal tolerance of offspring. To test whether there is parental effect of long acclimatization, adult sea cucumbers (Apostichopus japonicus) from the same broodstock were transplanted southward and acclimatized at high temperature in field mesocosms. Four groups of juvenile sea cucumbers whose parents experienced different durations of high temperature acclimatization were established. Upper thermal limits, oxygen consumption and levels of heat shock protein mRNA of juveniles was determined to compare thermal tolerance of individuals from different groups. Juvenile sea cucumbers whose parents experienced high temperature could acquire high thermal resistance. With the increase of parental exposure duration to high temperature, offspring became less sensitive to high temperature, as indicated by higher upper thermal limits (LT50), less seasonal variations of oxygen consumption, and stable oxygen consumption rates between chronic and acute thermal stress. The relatively high levels of constitutive expression of heat-shock proteins should contribute to the high thermal tolerance. Together, these results indicated that the existence of a parental effect of long acclimatization would increase thermal tolerance of juveniles and change the thermal sensitivity of sea cucumber to future climate change. PMID:26580550

Parental Effect of Long Acclimatization on Thermal Tolerance of Juvenile Sea Cucumber Apostichopus japonicus.

PubMed

Wang, Qing-Lin; Yu, Shan-Shan; Dong, Yun-Wei

2015-01-01

To evaluate the thermal resistance of marine invertebrates to elevated temperatures under scenarios of future climate change, it is crucial to understand parental effect of long acclimatization on thermal tolerance of offspring. To test whether there is parental effect of long acclimatization, adult sea cucumbers (Apostichopus japonicus) from the same broodstock were transplanted southward and acclimatized at high temperature in field mesocosms. Four groups of juvenile sea cucumbers whose parents experienced different durations of high temperature acclimatization were established. Upper thermal limits, oxygen consumption and levels of heat shock protein mRNA of juveniles was determined to compare thermal tolerance of individuals from different groups. Juvenile sea cucumbers whose parents experienced high temperature could acquire high thermal resistance. With the increase of parental exposure duration to high temperature, offspring became less sensitive to high temperature, as indicated by higher upper thermal limits (LT50), less seasonal variations of oxygen consumption, and stable oxygen consumption rates between chronic and acute thermal stress. The relatively high levels of constitutive expression of heat-shock proteins should contribute to the high thermal tolerance. Together, these results indicated that the existence of a parental effect of long acclimatization would increase thermal tolerance of juveniles and change the thermal sensitivity of sea cucumber to future climate change.

Biogeochemical alteration effects on U/Th geochronology of Pleistocene corals, Penguin Bank, Molokai, Hawai`i

NASA Astrophysics Data System (ADS)

Herries, K.; Rubin, K. H.; Hellebrand, E.

2017-12-01

Meltwater Pulse 1a (MWP-1a) is a large, relatively fast sea level rise event that occurred during the last deglaciation. Critical questions remain about the exact timing of MWP-1a and can be answered using high precision geochronology. Coral reefs are able to yield ideal records of sea level and ocean changes during and after deposition. Glacial far-field fossilized coral reefs, such as the well-preserved Penguin Bank reef near Molokai, Hawai'i, provide understandings to past sea level events that are relatively unaffected by local deglacial sea level effects. Using uranium-thorium dating of pristine corals, we are able date sea level events to an error of ±25-50 years. However, most Penguin Bank coral samples have been biogeochemically disturbed by other mesophotic organisms either during their lifetime or after their death. In these samples, the main disturbances observed in hand specimen are (1) overgrowth by coralline algae, (2) bioerosion from boring organisms, (3) living organisms, like sponges, inside coral skeletons, and (4) discoloration due to detrital materials. These disturbances are capable of disrupting the concentration of U in the coral and/or δ 234U measured. Seawater alteration-sensitive ratios, such as Sr/Ca and Mg/Ca, act as a proxy for potential diagenetic effects on U distribution in the corals. U and Th isotopic data acquired on both pristine and altered parts of the corals are being used to determine the impacts of alteration in the measured ages. With these new data, it may be possible to derive a more accurate timing of MWP-1a and provide a more general method of determining the suitability of coral specimens for dating of the last deglaciation and past climate change.

A Framework For Analysis Of Coastal Infrastructure Vunerabilty To Global Sea Level Rise

NASA Astrophysics Data System (ADS)

Obrien, P. S.; White, K. D.; Veatch, W.; Marzion, R.; Moritz, H.; Moritz, H. R.

2017-12-01

Recorded impacts of global sea rise on coastal water levels have been documented over the past 100 to 150 years. In the recent 40 years the assumption of hydrologic stationarity has been recognized as invalid. New coastal infrastructure designs must recognize the paradigm shift from hydrologic stationarity to non-stationarity in coastal hydrology. A framework for the evaluation of existing coastal infrastructure is proposed to effectively assess design vulnerability. Two data sets developed from existing structures are chosen to test a proposed framework for vunerabilty to global sea level rise, with the proposed name Climate Preparedness and Resilience Register (CPRR). The CPRR framework consists of four major elements; Datum Adjustment, Coastal Water Levels, Scenario Projections and Performance Thresholds.

Contemporary Arctic Sea Level

NASA Astrophysics Data System (ADS)

Cazenave, A. A.

2017-12-01

During recent decades, the Arctic region has warmed at a rate about twice the rest of the globe. Sea ice melting is increasing and the Greenland ice sheet is losing mass at an accelerated rate. Arctic warming, decrease in the sea ice cover and fresh water input to the Arctic ocean may eventually impact the Arctic sea level. In this presentation, we review our current knowledge of contemporary Arctic sea level changes. Until the beginning of the 1990s, Arctic sea level variations were essentially deduced from tide gauges located along the Russian and Norwegian coastlines. Since then, high inclination satellite altimetry missions have allowed measuring sea level over a large portion of the Arctic Ocean (up to 80 degree north). Measuring sea level in the Arctic by satellite altimetry is challenging because the presence of sea ice cover limits the full capacity of this technique. However adapted processing of raw altimetric measurements significantly increases the number of valid data, hence the data coverage, from which regional sea level variations can be extracted. Over the altimetry era, positive trend patterns are observed over the Beaufort Gyre and along the east coast of Greenland, while negative trends are reported along the Siberian shelf. On average over the Arctic region covered by satellite altimetry, the rate of sea level rise since 1992 is slightly less than the global mea sea level rate (of about 3 mm per year). On the other hand, the interannual variability is quite significant. Space gravimetry data from the GRACE mission and ocean reanalyses provide information on the mass and steric contributions to sea level, hence on the sea level budget. Budget studies show that regional sea level trends over the Beaufort Gyre and along the eastern coast of Greenland, are essentially due to salinity changes. However, in terms of regional average, the net steric component contributes little to the observed sea level trend. The sea level budget in the Arctic indicates a dominant mass contribution, especially in the Greenland, Norwegian, and Barents Seas sector.

The effects of sea level and palaeotopography on lithofacies distribution and geometries in heterozoan carbonates, south-eastern Spain

USGS Publications Warehouse

Johnson, C.L.; Franseen, E.K.; Goldstein, R.H.

2005-01-01

This study utilized three-dimensional exposures to evaluate how sea-level position and palaeotopography control the facies and geometries of heterozoan carbonates. Heterozoan carbonates were deposited on top of a Neogene volcanic substrate characterized by palaeotopographic highs, palaeovalleys, and straits that were formed by subaerial erosion, possibly original volcanic topography, and faults prior to carbonate deposition. The depositional sequence that is the focus of this study (DS1B) consists of 7-10 fining upward cycles that developed in response to relative sea-level fluctuations. A complete cycle has a basal erosion surface overlain by deposits of debrisflows and high-density turbidity currents, which formed during relative sea-level fall. Overlying tractive deposits most likely formed during the lowest relative position of sea level. Overlying these are debrites grading upward to high-density turbidites and low-density turbidites that formed during relative sea-level rise. The tops of the cycles consist of hemipelagic deposits that formed during the highest relative position of sea level. The cycles fine upward because upslope carbonate production decreased as relative sea level rose due to less surface area available for shallow-water carbonate production and partial drowning of substrates. The cycles are dominated by two end-member types of facies associations and stratal geometries that formed in response to fluctuating sea-level position over variable substrate palaeotopography. One end-member is termed 'flank flow cycle' because this type of cycle indicates dominant sediment transport down the flanks of palaeovalleys. Those cycles drape the substrate, have more debrites, high-density turbidites and erosion on palaeovalley flanks, and in general, the lithofacies fine down the palaeovalley flanks into the palaeovalley axes. The second end-member is termed 'axial flow cycle' because it indicates a dominance of sediment transport down the axes of palaeovalleys. Those cycles are characterized by debrites and high-density turbidites in palaeovalley axes, and lap out of strata against the flanks of palaeovalleys. Where and when an axial flow cycle or flank flow cycle developed appears to be related to the intersection of sea level with areas of gentle or steep substrate slopes, during an overall relative rise in sea level. Results from this study provide a model for similar systems that must combine carbonate principles for sediment production, palaeotopographic controls, and physical principles of sediment remobilization into deep water. ?? 2005 International Association of Sedimentologists.

Assessment of salinity intrusion in the James and Chickahominy Rivers as a result of simulated sea-level rise in Chesapeake Bay, East Coast, USA.

PubMed

Rice, Karen C; Hong, Bo; Shen, Jian

2012-11-30

Global sea level is rising, and the relative rate in the Chesapeake Bay region of the East Coast of the United States is greater than the worldwide rate. Sea-level rise can cause saline water to migrate upstream in estuaries and rivers, threatening freshwater habitat and drinking-water supplies. The effects of future sea-level rise on two tributaries of Chesapeake Bay, the James and Chickahominy (CHK) Rivers, were evaluated in order to quantify the salinity change with respect to the magnitude of sea-level rise. Such changes are critical to: 1) local floral and faunal habitats that have limited tolerance ranges to salinity; and 2) a drinking-water supply for the City of Newport News, Virginia. By using the three-dimensional Hydrodynamic-Eutrophication Model (HEM-3D), sea-level rise scenarios of 30, 50, and 100 cm, based on the U.S. Climate Change Science Program for the mid-Atlantic region for the 21st century, were evaluated. The model results indicate that salinity increases in the entire river as sea level rises and that the salinity increase in a dry year is greater than that in a typical year. In the James River, the salinity increase in the middle-to-upper river (from 25 to 50 km upstream of the mouth) is larger than that in the lower and upper parts of the river. The maximum mean salinity increase would be 2 and 4 ppt for a sea-level rise of 50 and 100 cm, respectively. The upstream movement of the 10 ppt isohaline is much larger than the 5 and 20 ppt isohalines. The volume of water with salinity between 10 and 20 ppt would increase greatly if sea level rises 100 cm. In the CHK River, with a sea-level rise of 100 cm, the mean salinity at the drinking-water intake 34 km upstream of the mouth would be about 3 ppt in a typical year and greater than 5 ppt in a dry year, both far in excess of the U.S. Environmental Protection Agency's secondary standard for total dissolved solids for drinking water. At the drinking-water intake, the number of days of salinity greater than 0.1 ppt increases with increasing sea-level rise; during a dry year, 0.1 ppt would be exceeded for more than 100 days with as small a rise as 30 cm. Copyright © 2012 Elsevier Ltd. All rights reserved.

Assessment of salinity intrusion in the James and Chickahominy Rivers as a result of simulated sea-level rise in Chesapeake Bay, East Coast, USA

USGS Publications Warehouse

Rice, Karen; Bo Hong,; Jian Shen,

2012-01-01

Global sea level is rising, and the relative rate in the Chesapeake Bay region of the East Coast of the United States is greater than the worldwide rate. Sea-level rise can cause saline water to migrate upstream in estuaries and rivers, threatening freshwater habitat and drinking-water supplies. The effects of future sea-level rise on two tributaries of Chesapeake Bay, the James and Chickahominy (CHK) Rivers, were evaluated in order to quantify the salinity change with respect to the magnitude of sea-level rise. Such changes are critical to: 1) local floral and faunal habitats that have limited tolerance ranges to salinity; and 2) a drinking-water supply for the City of Newport News, Virginia. By using the three-dimensional Hydrodynamic-Eutrophication Model (HEM-3D), sea-level rise scenarios of 30, 50, and 100 cm, based on the U.S. Climate Change Science Program for the mid-Atlantic region for the 21st century, were evaluated. The model results indicate that salinity increases in the entire river as sea level rises and that the salinity increase in a dry year is greater than that in a typical year. In the James River, the salinity increase in the middle-to-upper river (from 25 to 50 km upstream of the mouth) is larger than that in the lower and upper parts of the river. The maximum mean salinity increase would be 2 and 4 ppt for a sea-level rise of 50 and 100 cm, respectively. The upstream movement of the 10 ppt isohaline is much larger than the 5 and 20 ppt isohalines. The volume of water with salinity between 10 and 20 ppt would increase greatly if sea level rises 100 cm. In the CHK River, with a sea-level rise of 100 cm, the mean salinity at the drinking-water intake 34 km upstream of the mouth would be about 3 ppt in a typical year and greater than 5 ppt in a dry year, both far in excess of the U.S. Environmental Protection Agency's secondary standard for total dissolved solids for drinking water. At the drinking-water intake, the number of days of salinity greater than 0.1 ppt increases with increasing sea-level rise; during a dry year, 0.1 ppt would be exceeded for more than 100 days with as small a rise as 30 cm.

Guiding Users to Sea Level Change Data Through Content

NASA Astrophysics Data System (ADS)

Quach, N.; Abercrombie, S. P.; Boening, C.; Brennan, H. P.; Gill, K. M.; Greguska, F. R., III; Huang, T.; Jackson, R.; Larour, E. Y.; Shaftel, H.; Tenenbaum, L. F.; Zlotnicki, V.; Boeck, A.; Moore, B.; Moore, J.

2017-12-01

The NASA Sea Level Change Portal (https://sealevel.nasa.gov) is an immersive and innovative web portal for sea level change research that addresses the needs of diverse audiences, from scientists across disparate disciplines to the general public to policy makers and businesses. Since sea level change research involves vast amounts of data from multiple fields, it becomes increasingly important to come up with novel and effective ways to guide users to the data they need. News articles published on the portal contains links to relevant data. The Missions section highlights missions and projects as well as provide a logical grouping of the data. Tools available on the portal, such as the Data Analysis Tool, a data visualization and high-performance environment for sea level analysis, and the Virtual Earth System Laboratory, a 3D simulation application, describes and links to the source data. With over 30K Facebook followers and over 23K Twitter follower, the portal outreach team also leverages social media to guide users to relevant data. This presentation focuses on how the portal uses news articles, mission and project pages, tools, and social media to connect users to the data.

Nuisance Flooding and Relative Sea-Level Rise: the Importance of Present-Day Land Motion.

PubMed

Karegar, Makan A; Dixon, Timothy H; Malservisi, Rocco; Kusche, Jürgen; Engelhart, Simon E

2017-09-11

Sea-level rise is beginning to cause increased inundation of many low-lying coastal areas. While most of Earth's coastal areas are at risk, areas that will be affected first are characterized by several additional factors. These include regional oceanographic and meteorological effects and/or land subsidence that cause relative sea level to rise faster than the global average. For catastrophic coastal flooding, when wind-driven storm surge inundates large areas, the relative contribution of sea-level rise to the frequency of these events is difficult to evaluate. For small scale "nuisance flooding," often associated with high tides, recent increases in frequency are more clearly linked to sea-level rise and global warming. While both types of flooding are likely to increase in the future, only nuisance flooding is an early indicator of areas that will eventually experience increased catastrophic flooding and land loss. Here we assess the frequency and location of nuisance flooding along the eastern seaboard of North America. We show that vertical land motion induced by recent anthropogenic activity and glacial isostatic adjustment are contributing factors for increased nuisance flooding. Our results have implications for flood susceptibility, forecasting and mitigation, including management of groundwater extraction from coastal aquifers.

Identification of Transportation Infrastructure at Risk Due To Sea-Level Rise and Subsidence of Land In Coastal Louisiana

NASA Astrophysics Data System (ADS)

Tewari, S.; Palmer, W.; Manning, F.

2017-12-01

Climate change can affect coastal areas in a variety of ways. Coasts are sensitive to sea level rise, changes in the frequency/intensity of storms, increase in precipitation and storm surges. The resilience of transportation infrastructure located in Louisiana's coastal zone, against storm surges and climatic sea-level rise is critical. The net change in sea-level is affected by the increase in global sea level as well as land movement up or down. There are many places in coastal Louisiana that have a high subsidence rate. The subsidence could be related to excess extraction activities of oil and water, natural and/or human induced compaction, and tectonic movement. Where the land is sinking, the rate of relative sea level rise is larger than the global rate. Some of the fastest rates of relative sea level rise in the United States are occurring in areas where the land is sinking, including parts of the Gulf Coast. For example, coastal Louisiana has seen its relative sea level rise by eight inches or more in the last 50 years, which is about twice the global rate. Subsiding land in the Gulf area worsens the effects of relative sea level rise, increasing the risk of flooding in cities, inhabited islands, and tidal wetlands. The research team is investigating the trends for sea-level rise and land subsidence in coastal region of Louisiana. The variability in storm surges and its potential implication on the transportation infrastructure in the region is the focus of the study. The spatial maps will be created for spatial trends. This is extremely useful in being prepared for long-term natural hazards. The results of this study will be helpful to LADOTD and infrastructure managers and officials who are tasked with resiliency planning and management. Research results will also directly benefit university researchers in the state, Coastal Protection and Restoration Authority and LADOTD/LTRC through collaborative activity which will educate both professionals and the general public on issues related to transportation infrastructure in coastal areas while increasing overall public awareness. Also, the outcomes of the project will serve as an educational and research tool to convey to undergraduate and graduate students on how climate changes affect the transportation infrastructure safety/stability in the coastal region of the state.

Effect of Sea buckthorn on liver fibrosis: A clinical study

PubMed Central

Gao, Ze-Li; Gu, Xiao-Hong; Cheng, Feng-Tao; Jiang, Fo-Hu

2003-01-01

AIM: To appraise the effect of sea buckthorn (Hippophae rhamnoides) on cirrhotic patients. METHODS: Fifty cirrhotic patients of Child-Pugh grade A and B were randomly divided into two groups: Group A as the treated group (n = 30), taking orally the sea buckthorn extract, 15 g 3 times a day for 6 mo. Group B as the control group (n = 18), taking vitamin B complex one tablet, 3 times a day for 6 mo. The following tests were performed before and after the treatment in both groups to determine LN, HA, collagens types III and IV, cytokines IL-6 and TNFα, liver serum albumin, total bile acid, ALT, AST and prothrombin time. RESULTS: The serum levels of TNFα, IL-6, laminin and type IV collagen in group A were significantly higher than those in the control group. After a course of sea buckthorn treatment, the serum levels of LN, HA, collagen types III and IV, total bile acid (TBA) decreased significantly as compared with those before and after treatment in the control group. The sea buckthorn notably shortened the duration for normalization of aminotransferases. CONCLUSION: Sea buckthorn may be a hopeful drug for prevention and treatment of liver fibrosis. PMID:12854177

Short Lived Climate Pollutants cause a Long Lived Effect on Sea-level Rise: Analyzing climate metrics for sea-level rise

NASA Astrophysics Data System (ADS)

Sterner, E.; Johansson, D. J.

2013-12-01

Climate change depends on the increase of several different atmospheric pollutants. While long term global warming will be determined mainly by carbon dioxide, warming in the next few decades will depend to a large extent on short lived climate pollutants (SLCP). Reducing emissions of SLCPs could contribute to lower the global mean surface temperature by 0.5 °C already by 2050 (Shindell et al. 2012). Furthermore, the warming effect of one of the most potent SLCPs, black carbon (BC), may have been underestimated in the past. Bond et al. (2013) presents a new best estimate of the total BC radiative forcing (RF) of 1.1 W/m2 (90 % uncertainty bounds of 0.17 to 2.1 W/m2) since the beginning of the industrial era. BC is however never emitted alone and cooling aerosols from the same sources offset a majority of this RF. In the wake of calls for mitigation of SLCPs it is important to study other aspects of the climate effect of SLCPs. One key impact of climate change is sea-level rise (SLR). In a recent study, the effect of SLCP mitigation scenarios on SLR is examined. Hu et al (2013) find a substantial effect on SLR from mitigating SLCPs sharply, reducing SLR by 22-42% by 2100. We choose a different approach focusing on emission pulses and analyse a metric based on sea level rise so as to further enlighten the SLR consequences of SLCPs. We want in particular to understand the time dynamics of SLR impacts caused by SLCPs compared to other greenhouse gases. The most commonly used physical based metrics are GWP and GTP. We propose and evaluate an additional metric: The global sea-level rise potential (GSP). The GSP is defined as the sea level rise after a time horizon caused by an emissions pulse of a forcer to the sea level rise after a time horizon caused by an emissions pulse of a CO2. GSP is evaluated and compared to GWP and GTP using a set of climate forcers chosen to cover the whole scale of atmospheric perturbation life times (BC, CH4, N2O, CO2 and SF6). The study utilizes an upwelling diffusion energy balance model and focuses on the thermosteric part of sea-level rise. Example GSP results are 244, 15 and 278 for BC, CH4 and N2O for a time horizon of 100 years. Compare GWP and GTP values of 405, 24 and 288 as well as 62, 4.5 and 252. The main result of the study is that no climate forcer is in any absolute sense short lived when it comes to Sea Level impacts. All of the examined climate forcers have considerable influence on the thermosteric SLR, and the closely linked ocean heat content, on the time scale of centuries. The reason for this is that heat, once it has been induced by the climate drivers and warmed the surface ocean, is transported down into the slowly mixing oceans. References: Shindell, D. et al. Simultaneously mitigating near-term climate change and improving human health and food security. Science 335, 183-189 (2012). Bond, T. C. et al. Bounding the role of black carbon in the climate system: A scientific assessment. Journal of Geophysical Research: Atmospheres 118 5380-5552 (2013). Hu, A., Xu, Y., Tebaldi, C., Washington, W. M. & Ramanathan, V. Mitigation of short-lived climate pollutants slows sea-level rise. Nature Climate Change 3, 730-734 (2013).

A Comparison of Full and Empirical Bayes Techniques for Inferring Sea Level Changes from Tide Gauge Records

NASA Astrophysics Data System (ADS)

Piecuch, C. G.; Huybers, P. J.; Tingley, M.

2016-12-01

Sea level observations from coastal tide gauges are some of the longest instrumental records of the ocean. However, these data can be noisy, biased, and gappy, featuring missing values, and reflecting land motion and local effects. Coping with these issues in a formal manner is a challenging task. Some studies use Bayesian approaches to estimate sea level from tide gauge records, making inference probabilistically. Such methods are typically empirically Bayesian in nature: model parameters are treated as known and assigned point values. But, in reality, parameters are not perfectly known. Empirical Bayes methods thus neglect a potentially important source of uncertainty, and so may overestimate the precision (i.e., underestimate the uncertainty) of sea level estimates. We consider whether empirical Bayes methods underestimate uncertainty in sea level from tide gauge data, comparing to a full Bayes method that treats parameters as unknowns to be solved for along with the sea level field. We develop a hierarchical algorithm that we apply to tide gauge data on the North American northeast coast over 1893-2015. The algorithm is run in full Bayes mode, solving for the sea level process and parameters, and in empirical mode, solving only for the process using fixed parameter values. Error bars on sea level from the empirical method are smaller than from the full Bayes method, and the relative discrepancies increase with time; the 95% credible interval on sea level values from the empirical Bayes method in 1910 and 2010 is 23% and 56% narrower, respectively, than from the full Bayes approach. To evaluate the representativeness of the credible intervals, empirical Bayes and full Bayes methods are applied to corrupted data of a known surrogate field. Using rank histograms to evaluate the solutions, we find that the full Bayes method produces generally reliable error bars, whereas the empirical Bayes method gives too-narrow error bars, such that the 90% credible interval only encompasses 70% of true process values. Results demonstrate that parameter uncertainty is an important source of process uncertainty, and advocate for the fully Bayesian treatment of tide gauge records in ocean circulation and climate studies.

Probabilistic assessment of sea level during the last interglacial stage.

PubMed

Kopp, Robert E; Simons, Frederik J; Mitrovica, Jerry X; Maloof, Adam C; Oppenheimer, Michael

2009-12-17

With polar temperatures approximately 3-5 degrees C warmer than today, the last interglacial stage (approximately 125 kyr ago) serves as a partial analogue for 1-2 degrees C global warming scenarios. Geological records from several sites indicate that local sea levels during the last interglacial were higher than today, but because local sea levels differ from global sea level, accurately reconstructing past global sea level requires an integrated analysis of globally distributed data sets. Here we present an extensive compilation of local sea level indicators and a statistical approach for estimating global sea level, local sea levels, ice sheet volumes and their associated uncertainties. We find a 95% probability that global sea level peaked at least 6.6 m higher than today during the last interglacial; it is likely (67% probability) to have exceeded 8.0 m but is unlikely (33% probability) to have exceeded 9.4 m. When global sea level was close to its current level (>or=-10 m), the millennial average rate of global sea level rise is very likely to have exceeded 5.6 m kyr(-1) but is unlikely to have exceeded 9.2 m kyr(-1). Our analysis extends previous last interglacial sea level studies by integrating literature observations within a probabilistic framework that accounts for the physics of sea level change. The results highlight the long-term vulnerability of ice sheets to even relatively low levels of sustained global warming.

Influences of Relative Sea-Level Rise and Mississippi River Delta Plain Evolution on the Holocene Middle Amite River, Southeastern Louisiana

USGS Publications Warehouse

Autin, W.J.

1993-01-01

The Holocene geomorphic history of southeastern Louisiana's middle Amite River is recorded in the stratigraphy of three alloformations, identified in decreasing age as the Watson (WAT), Denham Springs (DS), and Magnolia Bridge (MAG). The WAT meander belt formed by at least 9000 yr B.P., when sea level was lower and the Amite River was tributary to a larger ancestral drainage basin. The DS became an active meander belt by at least 3000 yr B.P., in response to relative sea-level rise and eastward progradation of the Mississippi River delta plain. The MAG developed its meander belt, in part, during the European settlement of the drainage basin, and is now attempting to adjust to modern anthropogenic influences. Geomorphic influences on the middle Amite River floodplain have temporal and spatial components that induce regional- and local-scale effects. Regional extrinsic influences caused meander belt avulsion that produced alloformations. However, local influences produced intrinsic geomorphic thresholds that modified channel morphology within a meander belt but did not induce alloformation development. Base-level influences of the relative sea-level rise and the Mississippi River delta plain were so dominant that the effects of possible climate change were not recognized in the Holocene Amite River system.

Differential RNA regulation by staphylococcal enterotoxins A and B in murine macrophages

NASA Technical Reports Server (NTRS)

Chapes, S. K.; Beharka, A. A.; Hart, M. E.; Smeltzer, M. S.; Iandolo, J. J.; Spooner, B. S. (Principal Investigator)

1994-01-01

Staphylococcal enterotoxin A (SEA) is significantly better than enterotoxin B (SEB) in activating tumor necrosis factor (TNF) secretion by B6MP102 cells. Both toxins bound to B6MP102 cells; however, SEB competed less effectively with SEA than SEA competed with SEB. This suggested that receptors unique to SEA were present on B6MP102 cells. Signal transduction occurred in response to both toxins. Within 30 s after addition, SEA and SEB significantly increased the F-actin concentration in B6MP102 cells. However, only SEA induced increased TNF mRNA levels. B6MP102 cells incubated with interferon-gamma and SEB secreted TNF. However, enhanced mRNA expression was delayed and the concentration of TNF secreted was less than that of B6MP102 cells stimulated with SEA. Although these data suggest that receptors unique to SEA are present on B6MP102 cells, they also indicate that staphylococcal enterotoxins differentially regulate TNF at the RNA level, perhaps because of differences in binding to the plasma membrane.

Effect of fasting during the month of Ramadan on serum levels of luteinizing hormone and testosterone in people living in the below sea level environment in the Jordan Valley.

PubMed

El-Migdadi, Fayig; Shotar, Ali; El-Akawi, Zeyad; Banihani, Ibrahim; Abudheese, Rola

2004-01-01

To study a possible effect of Ramadan fasting on luteinizing hormone and testosterone in people of the Jordan Valley. A comparative study (n=40) of serum levels of luteinizing hormone (LH) and testosterone (T) between people living in the Jordan Valley (JV), n=20, 360 meters below sea level, and those living in Ramtha City (RC), n=20, 600 meters above sea level, was conducted in December, 1998. A similar study (n=40) was also done during January 1999 in fasting people during the month of Ramadan. Serum levels of LH in non-fasting people of the JV were statistically similar to those in people of RC. There was also no difference in serum levels of T between non-fasting people of the JV and those in RC. Serum levels of LH in fasting people of the JV were statistically indifferent from those fasting in RC. Serum T levels in fasting people of the JV, on the other hand, were higher than those in fasting people of RC (76+/-18.3 ng/ml compared to 62.7+/-24.2 ng/ml). It is probably the environmental factors such as the higher barometric pressure of the JV compared to that at above sea level that play a role in higher serum levels of T in people of the JV. Other factors, such as genetic background and/or the cultural and nutritional characteristics of the people of the JV, may also contribute to this difference in serum T levels.

[THE EFFECT OF 5 DAYS IMMERSION IN DEAD SEA WATER ON BLOOD GLUCOSE LEVELS IN TYPE 2 DIABETES MELLITUS PATIENTS].

PubMed

Brzezinski Sinai, Isaac; Lior, Yotam; Brzezinski Sinai, Noa; Harari, Marco; Liberty, Idit F

2016-02-01

Body immersion in plain water or mineral water induces significant and unique physiological changes in most body systems. In a previous pilot study, a significant reduction in blood glucose levels among diabetes mellitus (DM) patients was found following a single immersion in Dead Sea water but not after immersion in plain water. To study the immediate and long term effects of immersion in mineral water for five consecutive days on blood glucose in patients with type 2 DM. A total of 34 patients with type 2 DM were divided into 2 groups: The first immersed in a plain water pool and the second immersed in a Dead Sea water pool; both pools were warmed to a temperature of 35°C. Immersions for 20 minutes occurred twice daily: two hours after breakfast and before dinner. Seven samples of capillary blood glucose levels were taken: fasting, before and after every immersion, prior to lunch and before bedtime. Hemoglobin A1C (HbA1c) was taken prior to the study and a re-check was conducted during the 12 weeks following the study. Blood glucose levels significantly decreased immediately after immersion both in Dead Sea water and plain water compared to their values prior to immersion (p<0.001). No significant difference was noted between both types of water. A decrease in fasting glucose levels was observed only in the group immersed in Dead Sea water when compared to plain water (6.83±5.68 mg/dl versus 4.37±1.79 respectively and the difference was close to statistical significance (p=0.071. There were no changes in HbA1c levels. Immersion for 20 minutes in water (Dead Sea or plain water) at a temperature of 35°C induced an immediate reduction in glucose levels in patients with type 2 DM.

Evaluating the effect of synchronized sea lice treatments in Chile.

PubMed

Arriagada, G; Stryhn, H; Sanchez, J; Vanderstichel, R; Campistó, J L; Rees, E E; Ibarra, R; St-Hilaire, S

2017-01-01

The sea louse is considered an important ectoparasite that affects farmed salmonids around the world. Sea lice control relies heavily on pharmacological treatments in several salmon-producing countries, including Chile. Among options for drug administration, immersion treatments represent the majority of antiparasitic control strategies used in Chile. As a topical procedure, immersion treatments do not induce a long lasting effect; therefore, re-infestation from neighbouring farms may undermine their efficacy. Synchronization of treatments has been proposed as a strategy to improve immersion treatment performance, but it has not been evaluated so far. Using a repeated-measures linear mixed-effect model, we evaluated the impact of treatment synchronization of neighbouring farms (within 10km seaway distance) on the adult lice mean abundance from weeks 2 to 8 post-treatment on rainbow trout and Atlantic salmon farms in Chile, while controlling for external and internal sources of lice before the treatments, and also for environmental and fish-related variables. Results indicate that treatment synchronization was significantly associated with lower adult lice levels from weeks 5 to 7 after treatment. This relationship appeared to be linear, suggesting that higher levels of synchronization may result in lower adult sea lice levels during these weeks. These findings suggest that synchronization can improve the performance of immersion delousing treatments by keeping sea lice levels low for a longer period of time. Our results may be applicable to other regions of the world where immersion treatments are widely used. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Upper Cretaceous sequences and sea-level history, New Jersey Coastal Plain

USGS Publications Warehouse

Miller, K.G.; Sugarman, P.J.; Browning, J.V.; Kominz, M.A.; Olsson, R.K.; Feigenson, M.D.; Hernandez, J.C.

2004-01-01

We developed a Late Cretaceous sealevel estimate from Upper Cretaceous sequences at Bass River and Ancora, New Jersey (ODP [Ocean Drilling Program] Leg 174AX). We dated 11-14 sequences by integrating Sr isotope and biostratigraphy (age resolution ??0.5 m.y.) and then estimated paleoenvironmental changes within the sequences from lithofacies and biofacies analyses. Sequences generally shallow upsection from middle-neritic to inner-neritic paleodepths, as shown by the transition from thin basal glauconite shelf sands (transgressive systems tracts [TST]), to medial-prodelta silty clays (highstand systems tracts [HST]), and finally to upper-delta-front quartz sands (HST). Sea-level estimates obtained by backstripping (accounting for paleodepth variations, sediment loading, compaction, and basin subsidence) indicate that large (>25 m) and rapid (???1 m.y.) sea-level variations occurred during the Late Cretaceous greenhouse world. The fact that the timing of Upper Cretaceous sequence boundaries in New Jersey is similar to the sea-level lowering records of Exxon Production Research Company (EPR), northwest European sections, and Russian platform outcrops points to a global cause. Because backstripping, seismicity, seismic stratigraphic data, and sediment-distribution patterns all indicate minimal tectonic effects on the New Jersey Coastal Plain, we interpret that we have isolated a eustatic signature. The only known mechanism that can explain such global changes-glacio-eustasy-is consistent with foraminiferal ??18O data. Either continental ice sheets paced sea-level changes during the Late Cretaceous, or our understanding of causal mechanisms for global sea-level change is fundamentally flawed. Comparison of our eustatic history with published ice-sheet models and Milankovitch predictions suggests that small (5-10 ?? 106 km3), ephemeral, and areally restricted Antarctic ice sheets paced the Late Cretaceous global sea-level change. New Jersey and Russian eustatic estimates are typically one-half of the EPR amplitudes, though this difference varies through time, yielding markedly different eustatic curves. We conclude that New Jersey provides the best available estimate for Late Cretaceous sea-level variations. ?? 2004 Geological Society America.

Quantifying and Projecting Relative Sea-Level Rise in The Deltaic Regions

NASA Astrophysics Data System (ADS)

Shum, C. K.; Chung-Yen, K.; Calmant, S.; Yang, T. Y.; Guo, Q.; Jia, Y.; Ballu, V.; Guo, J.; Karptychev, M.; Krien, Y.; Kusche, J.; Tseng, K. H.; Wan, J.; Uebbing, B.

2017-12-01

Half of the world's population lives within 200 km of coastlines. Accelerated sea-level rise, compounded by effects of population growth, severe land subsidence due to fluvial sediment compaction/load, and anthropogenic oil and natural gas and ground water extraction, tectonic motion, and the increasing threat of more intense and more frequent cyclone-driven storm surges, have exacerbated the vulnerability of many of world's deltaic regions, including the Bangladesh and the Mississippi River Deltas. At present, understanding and quantifying the natural and anthropogenic processes governing these solid Earth vertical motion processes remain elusive to enable addressing coastal vulnerability due to current and future projection of relative sea-level rise for deltaic regions at the regional scales. Bangladesh, a low-lying and one of the most densely populated countries in the world located at the Bay of Bengal, is prone to transboundary monsoonal flooding, and is believed to be aggravated by more frequent and intensified cyclones resulting from anthropogenic climate change. The Mississippi River Deltaic region has been severely subsiding due primarily to fluvial sediment compaction and load during the last 10 centuries, oil/gas and groundwater extractions, and commercial developments, making it vulnerable to sea-level rise hazards. Here we present results of global geocentric sea-level rise, 1950-2016, separating vertical land motion at global tide gauge datum, by integrating tide gauge and radar altimeter records in a novel sea-level reconstruction scheme, focusing on the Mississippi River and the Bangladesh Deltas. We then integrate the resulting sea level estimates with historic imageries, GPS and InSAR data, as well as sediment isostatic and load model predicted present-day land subsidence, to constrain the 3D land motion to study the impacts of various scenarios of future relative sea level projections on the Bangladesh Delta to the end of the 21st Century and beyond.

Sea level controls on the textural characteristics and depositional architecture of the Hueneme and associated submarine fan systems, Santa Monica Basin, California

USGS Publications Warehouse

Normark, W.R.; Piper, D.J.W.; Hiscott, R.N.

1998-01-01

Hueneme and Dume submarine fans in Santa Monica Basin consist of sandy channel and muddy levee facies on the upper fan. lenticular sand sheets on the middle fan. and thinly bedded turbidite and hemipelagic facies elsewhere. Fifteen widely correlatable key seismic reflections in high-resolution airgun and deep-towed boomer profiles subdivide the fan and basin deposits into time-slices that show different thickness and seismic-facies distributions, inferred to result from changes in Quaternary sea level and sediment supply. At times of low sea level, highly efficient turbidity currents generated by hyperpycnal flows or sediment failures at river deltas carry sand well out onto the middle-fan area. Thick, muddy flows formed rapidly prograding high levees mainly on the western (right-hand) side of three valleys that fed Hueneme fan at different times: the most recently active of the lowstand fan valleys. Hueneme fan valley, now heads in Hueneme Canyon. At times of high sea level, fans receive sand from submarine canyons that intercept littoral-drift cells and mixed sediment from earthquake-triggered slumps. Turbidity currents are confined to 'underfit' talweg channels in fan valleys and to steep, small, basin-margin fans like Dume fan. Mud is effectively separated from sand at high sea level and moves basinward across the shelf in plumes and in storm-generated lutite flows, contributing to a basin-floor blanket that is locally thicker than contemporary fan deposits and that onlaps older fans at the basin margin. The infilling of Santa Monica Basin has involved both fan and basin-floor aggradation accompanied by landward and basinward facies shifts. Progradation was restricted to the downslope growth of high muddy levees and the periodic basinward advance of the toe of the steeper and sandier Dume fan. Although the region is tectonically active, major sedimentation changes can be related to eustatic sea-level changes. The primary controls on facies shifts and fan growth appear to be an interplay of texture of source sediment, the efficiency with which turbidity currents transport sand, and the effects of delta distributary switching, all of which reflect sea-level changes.

Scientific evidence of the therapeutic effects of dead sea treatments: a systematic review.

PubMed

Katz, Uriel; Shoenfeld, Yehuda; Zakin, Varda; Sherer, Yaniv; Sukenik, Shaul

2012-10-01

The Dead Sea, the deepest and most saline lake on earth, has been known from biblical times for its healing properties. The aim of this systematic review was to present critically the level of evidence for the claims of therapeutic effects of Dead Sea treatments in several rheumatologic diseases and psoriasis as well as to review these treatments' safety. All articles cited in MEDLINE under the query, "Dead Sea," were reviewed. We found bona fide evidence that Dead Sea treatments are especially effective in psoriasis due to both the special characteristics of solar ultraviolet radiation in the Dead Sea and the Dead Sea water balneotherapy. Dead Sea mud and Dead Sea balneotherapy have been found to be beneficial in rheumatologic diseases, including rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, and knee osteoarthritis. In the safety analysis, we found no evidence for an increase in skin neoplasia, although skin actinic damage seems to be increased in patients treated in the Dead Sea. Dead Sea treatments do not lead to worsening of blood pressure. Substantial ingestion of Dead Sea water (generally in unusual near-drowning cases) is toxic and can result in cardiac rhythm disturbances because of electrolyte concentration abnormalities. Laboratory analysis of Dead Sea mud did not reveal mineral concentrations that could represent a health concern for their intended use. Dead Sea treatments are beneficial in several rheumatologic diseases and psoriasis and have a good safety profile. Copyright © 2012 Elsevier Inc. All rights reserved.

What Causes the North Sea Level to Rise Faster over the Last Decade ?

NASA Astrophysics Data System (ADS)

Karpytchev, Mikhail; Letetrel, Camille

2013-04-01

We combined tide gauge records (PSMSL) and satellite altimetry data (TOPEX/POSEIDON-JASON 1-2) to reconstruct the mean level of the North Sea and the Norwegian Sea Shelf (NS-NSS) over 1950-2012. The reconstructed NS-NSS mean sea level fluctuations reveal a pronounced interannual variability and a strong sea level acceleration since the mid-1990's. In order to understand the causes of this acceleration, the NS-NSS mean sea level was cross-correlated with the North Atlantic Oscillation and Arctic Oscillation indices. While the interannual variability of the mean sea level correlates well with the NAO/AO indices, the observed acceleration in the NS-NSS mean level is not linked linearly to the NAO/AO fluctuations. On the other hand, the Empirical Orthogonal Functions (EOF) analysis of steric sea level variations in the eastern North Atlantic gives a dominant EOF pattern (55% of variance explained) that varies on a decadal scale very closely to the NS-NSS mean level flcutuations. Also, the amplification in the temporal amplitude of the dominant steric sea level EOF corresponds to the acceleration observed in the NS-NSS mean sea level signal. This suggests that decadal variations in the mean level of the North Sea - the Norwegian Sea Shelf reflect changes in the Subpolar Front currents (Rossby, 1996).

Influence of dietary probiotic Bacillus TC22 and Prebiotic fructooligosaccharide on growth, immune responses and disease resistance against Vibrio splendidus infection in sea cucumber Apostichopus japonicus

NASA Astrophysics Data System (ADS)

Zhao, Yancui; Mai, Kangsen; Xu, Wei; Zhang, Wenbing; Ai, Qinghui; Zhang, Yanjiao; Wang, Xiaojie; Liufu, Zhiguo

2011-09-01

The effects of probiotic Bacillus TC22 (isolated from intestine of infected sea cucumber) and prebiotic fructooligosaccharide (FOS) on growth, immunity and disease resistance in sea cucumber Apostichopus japonicus were studied. Six experimental diets were formulated with combinations of three levels of TC22 (0, 107 and 109 CFU g-1 diet) and two levels of FOS (0 and 0.5%) in a 3 × 2 factorial experiment. At the end of the 8-week feeding trial, animals were challenged by injecting Vibrio splendidus. The results revealed that the specific growth rates (SGR) of sea cucumbers were not affected by TC22 and FOS, or the interaction between TC22 and FOS ( P > 0.05). However, there were significant interactions between TC22 and FOS for immune response and disease resistance in sea cucumbers ( P < 0.05). When sea cucumbers were fed with TC22 at 109 CFU g-1 feed and 0.5% FOS alone or in combination, the phagocytosis, respiratory burst and phenoloxidase activity of sea cucumber coelomocytes were significantly enhanced; the disease resistance against V. splendidus infection was also increased significantly ( P < 0.05). However, dietary combination of TC22 at 109 CFU g-1 diet and 0.5% FOS did not yield significantly higher efficiency than either TC22 at 109 CFU g-1 diet or 0.5% FOS used alone ( P > 0.05). Therefore, further studies should examine the effects of combinations of other levels of FOS (> 0.5% or < 0.5%) and TC22 on the immunity and disease resistance of sea cucumbers.

Reconstruction of Local Sea Levels at South West Pacific Islands—A Multiple Linear Regression Approach (1988-2014)

NASA Astrophysics Data System (ADS)

Kumar, V.; Melet, A.; Meyssignac, B.; Ganachaud, A.; Kessler, W. S.; Singh, A.; Aucan, J.

2018-02-01

Rising sea levels are a critical concern in small island nations. The problem is especially serious in the western south Pacific, where the total sea level rise over the last 60 years has been up to 3 times the global average. In this study, we aim at reconstructing sea levels at selected sites in the region (Suva, Lautoka—Fiji, and Nouméa—New Caledonia) as a multilinear regression (MLR) of atmospheric and oceanic variables. We focus on sea level variability at interannual-to-interdecadal time scales, and trend over the 1988-2014 period. Local sea levels are first expressed as a sum of steric and mass changes. Then a dynamical approach is used based on wind stress curl as a proxy for the thermosteric component, as wind stress curl anomalies can modulate the thermocline depth and resultant sea levels via Rossby wave propagation. Statistically significant predictors among wind stress curl, halosteric sea level, zonal/meridional wind stress components, and sea surface temperature are used to construct a MLR model simulating local sea levels. Although we are focusing on the local scale, the global mean sea level needs to be adjusted for. Our reconstructions provide insights on key drivers of sea level variability at the selected sites, showing that while local dynamics and the global signal modulate sea level to a given extent, most of the variance is driven by regional factors. On average, the MLR model is able to reproduce 82% of the variance in island sea level, and could be used to derive local sea level projections via downscaling of climate models.

How Much Are Floridians Willing to Pay for Protecting Sea Turtles from Sea Level Rise?

NASA Astrophysics Data System (ADS)

Hamed, Ahmed; Madani, Kaveh; Von Holle, Betsy; Wright, James; Milon, J. Walter; Bossick, Matthew

2016-01-01

Sea level rise (SLR) is posing a great inundation risk to coastal areas. Some coastal nesting species, including sea turtle species, have experienced diminished habitat from SLR. Contingent valuation method (CVM) was used in an effort to assess the economic loss impacts of SLR on sea turtle nesting habitats for Florida coasts; and to elicit values of willingness to pay (WTP) of Central Florida residents to implement certain mitigation strategies, which would protect Florida's east coast sea turtle nesting areas. Using the open-ended and dichotomous choice CVM, we sampled residents of two Florida communities: Cocoa Beach and Oviedo. We estimated the WTP of households from these two cities to protect sea turtle habitat to be between 42 and 57 per year for 5 years. Additionally, we attempted to assess the impact of the both the respondents' demographics and their perception toward various situations on their WTP value. Findings include a negative correlation between the age of a respondent and the probability of an individual willing to pay the hypothetical WTP amount. We found that WTP of an individual was not dependent on prior knowledge of the effects of SLR on sea turtle habitat. The greatest indicators of whether or not an individual was willing to pay to protect sea turtle habitat were the respondents' perception regarding the trustworthiness and efficiency of the party which will implement the conservation measures and their confidence in the conservation methods used. Respondents who perceive sea turtles having an effect on their life were also more likely to pay.

How Much Are Floridians Willing to Pay for Protecting Sea Turtles from Sea Level Rise?

PubMed

Hamed, Ahmed; Madani, Kaveh; Von Holle, Betsy; Wright, James; Milon, J Walter; Bossick, Matthew

2016-01-01

Sea level rise (SLR) is posing a great inundation risk to coastal areas. Some coastal nesting species, including sea turtle species, have experienced diminished habitat from SLR. Contingent valuation method (CVM) was used in an effort to assess the economic loss impacts of SLR on sea turtle nesting habitats for Florida coasts; and to elicit values of willingness to pay (WTP) of Central Florida residents to implement certain mitigation strategies, which would protect Florida's east coast sea turtle nesting areas. Using the open-ended and dichotomous choice CVM, we sampled residents of two Florida communities: Cocoa Beach and Oviedo. We estimated the WTP of households from these two cities to protect sea turtle habitat to be between $42 and $57 per year for 5 years. Additionally, we attempted to assess the impact of the both the respondents' demographics and their perception toward various situations on their WTP value. Findings include a negative correlation between the age of a respondent and the probability of an individual willing to pay the hypothetical WTP amount. We found that WTP of an individual was not dependent on prior knowledge of the effects of SLR on sea turtle habitat. The greatest indicators of whether or not an individual was willing to pay to protect sea turtle habitat were the respondents' perception regarding the trustworthiness and efficiency of the party which will implement the conservation measures and their confidence in the conservation methods used. Respondents who perceive sea turtles having an effect on their life were also more likely to pay.

Effects of dietary cadmium on growth, antioxidants and bioaccumulation of sea cucumber (Apostichopus japonicus) and influence of dietary vitamin C supplementation.

PubMed

Wang, Jing; Ren, Tongjun; Wang, Fuqiang; Han, Yuzhe; Liao, Mingling; Jiang, Zhiqiang; Liu, Haiying

2016-07-01

The effects of dietary cadmium (Cd) supplementation on growth, antioxidant capacity and accumulation of Cd in tissues (body wall, digestive tracts, and respiratory tree) of sea cucumber, Apostichopus japonicus, exposed to sub-chronic concentrations (0, 10, 50, 100, and 500mg Cd/kg dry weight) of Cd were investigated. In addition, the potential protective effects of vitamin C (L-ascorbic acid, AsA) against the effects of Cd on sea cucumbers were investigated. Sea cucumbers were exposed to dietary Cd for 30 days, after which another group of healthy sea cucumbers was supplied diet supplemented with mixed Cd and AsA for another 30 days. Cd exposure for 30 days resulted in increased Cd accumulation in tissues of sea cucumbers with exposure time and concentration. The order of Cd accumulation in organs was digestive tracts>respiratory tree>body wall. On day 30, the body weight gain (BWG) and specific growth rate (SGR) decreased significantly (P<0.05) in the 500mg Cd/kg treatment. Superoxide dismutase (SOD) activity, glutathione peroxidase (GSH-Px) activity and catalase (CAT) activity in the coelomic fluid of sea cucumbers decreased with increasing dietary Cd concentration, but malondialdehyde (MDA) content in the coelomic fluid increased. Providing diet supplemented with Cd and AsA indicated that although sea cucumbers exhibited signs of Cd toxicity, no death occurred in response to 50mg Cd/kg for 30 days. Based on these findings, five treatments were provided: 50mg Cd/kg+0mg AsA/kg, 50mg Cd/kg+ 3000mg AsA/kg, 50mg Cd/kg+ 5000mg AsA/kg, 50mg Cd/kg+10,000mg AsA/kg, and 50mg Cd/kg+15,000mg AsA/kg. The BWG and SGR of sea cucumbers fed the AsA supplemented diet mixed with Cd increased. Additionally, MDA levels in coelomic fluid were negatively correlated with dietary AsA levels, while antioxidant capacities (SOD, GSH-Px and CAT) were positively correlated with dietary AsA levels. Moreover, Cd accumulation in tissues decreased in response to dietary AsA supplementation of treatments. Overall, antioxidant capacity and bioaccumulation in sea cucumber was found to decrease and be induced in response to Cd, but vitamin C mitigated these effects, with 5000mg AsA/kg providing the optimum protection against 50mg/kg Cd. Copyright © 2016 Elsevier Inc. All rights reserved.

New Constraints from the Seychelles on the Timing and Magnitude of Peak Global Mean Sea Level during the Last Interglacial

NASA Astrophysics Data System (ADS)

Vyverberg, K.; Dechnik, B.; Dutton, A.; Webster, J.; Zwartz, D.; Edwards, R. L.

2016-12-01

Projecting the rate of future sea-level rise remains a primary challenge associated with continued climate change. However, uncertainties remain in our understanding of the rate of polar ice sheet retreat in warmer-than-present climates. To address this issue, we present a new sea level reconstruction from the tectonically stable granitic Seychelles based on Last Interglacial coral ages and elevations within their sedimentary and stratigraphic context, including estimates of paleo-water depth based on newly defined coralgal assemblages. The reef facies analyzed here has a narrow and shallow paleowater depth range (<2 m) providing increased control on the absolute position of sea level during this time period. Corrected for local glacial isostatic adjustment effects including the fingerprint associated with polar ice sheet mass loss, corals found in primary growth position within in situ coralgal reef framework confirm that global mean sea level (GMSL) was nearly 6 m above present early in the interglacial period. Each coral was dated in triplicate and screened for anomalous U-series geochemistry parameters. The combination of age-elevation data with the sedimentary micro and macro facies and stratigraphic analysis reveals a sea-level rise over 5-6 thousand years that is punctuated by repeated episodes of reef disturbance. These episodes are marked stratigraphically by coral rubble layers or extensive lateral encrustations of Millepora sp. that are infested with coral-dwelling barnacles. These disturbance layers may have been generated through internal reef processes and/or external agents, including coral disease, bleaching, predation, hurricanes, or sub-aerial exposure. In total, these new observations provide improved constraints on the timing, magnitude, and rates of sea-level rise during the Last Interglacial.

Estuarine Response to River Flow and Sea-Level Rise under Future Climate Change and Human Development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Zhaoqing; Wang, Taiping; Voisin, Nathalie

Understanding the response of river flow and estuarine hydrodynamics to climate change, land-use/land-cover change (LULC), and sea-level rise is essential to managing water resources and stress on living organisms under these changing conditions. This paper presents a modeling study using a watershed hydrology model and an estuarine hydrodynamic model, in a one-way coupling, to investigate the estuarine hydrodynamic response to sea-level rise and change in river flow due to the effect of future climate and LULC changes in the Snohomish River estuary, Washington, USA. A set of hydrodynamic variables, including salinity intrusion points, average water depth, and salinity of themore » inundated area, were used to quantify the estuarine response to river flow and sea-level rise. Model results suggest that salinity intrusion points in the Snohomish River estuary and the average salinity of the inundated areas are a nonlinear function of river flow, although the average water depth in the inundated area is approximately linear with river flow. Future climate changes will shift salinity intrusion points further upstream under low flow conditions and further downstream under high flow conditions. In contrast, under the future LULC change scenario, the salinity intrusion point will shift downstream under both low and high flow conditions, compared to present conditions. The model results also suggest that the average water depth in the inundated areas increases linearly with sea-level rise but at a slower rate, and the average salinity in the inundated areas increases linearly with sea-level rise; however, the response of salinity intrusion points in the river to sea-level rise is strongly nonlinear.« less

Coupling landscapes to solid-Earth deformation over the ice-age

NASA Astrophysics Data System (ADS)

Pico, T.; Mitrovica, J. X.; Ferrier, K.; Braun, J.

2016-12-01

We present initial results of a coupled ice-age sea level - landscape evolution code. Deformation of the solid Earth in response to the growth and ablation of continental ice sheets produces spatially-variable patterns of sea-level change. Recent modeling has considered the impact of sedimentation and erosion on sea level predictions across the last glacial cycle, but these studies have imposed, a-priori, a record of sediment flux and erosion, rather than computing them from a physics-based model of landscape evolution in the presence of sea-level (topography) changes. These topography changes range from 1-10 m/kyr in the near and intermediate field of the Late Pleistocene ice cover, and are thus comparable to (or exceed) tectonic rates in such regions. Our simulations aim to address the following question: how does solid-Earth deformation influence the evolution of landscapes over glacial periods? To address this issue, we couple a highly-efficient landscape evolution code, Fastscape (Braun & Willett, 2013), to a global, gravitationally-self consistent sea-level theory. Fastscape adopts standard geomorphic laws governing incision and marine deposition, and the sea-level model is based on the canonical work of Farrell & Clark (1976), with extensions to include the effects of rotation and time varying shoreline geometries (Kendall et al., 2005), and sediment erosion and deposition (Dalca et al, 2013). We will present global results and focus on a few regional case studies where deposition rates from a dataset of sedimentary cores can be used as a check on the simulations. These predictions quantify the influence of sea-level change (including that associated with sedimentation and erosion) on geomorphic drivers of landscape evolution, and in turn, the solid Earth deformation caused by these surface processes over an ice age.

A Simple Model Framework to Explore the Deeply Uncertain, Local Sea Level Response to Climate Change. A Case Study on New Orleans, Louisiana

NASA Astrophysics Data System (ADS)

Bakker, Alexander; Louchard, Domitille; Keller, Klaus

2016-04-01

Sea-level rise threatens many coastal areas around the world. The integrated assessment of potential adaptation and mitigation strategies requires a sound understanding of the upper tails and the major drivers of the uncertainties. Global warming causes sea-level to rise, primarily due to thermal expansion of the oceans and mass loss of the major ice sheets, smaller ice caps and glaciers. These components show distinctly different responses to temperature changes with respect to response time, threshold behavior, and local fingerprints. Projections of these different components are deeply uncertain. Projected uncertainty ranges strongly depend on (necessary) pragmatic choices and assumptions; e.g. on the applied climate scenarios, which processes to include and how to parameterize them, and on error structure of the observations. Competing assumptions are very hard to objectively weigh. Hence, uncertainties of sea-level response are hard to grasp in a single distribution function. The deep uncertainty can be better understood by making clear the key assumptions. Here we demonstrate this approach using a relatively simple model framework. We present a mechanistically motivated, but simple model framework that is intended to efficiently explore the deeply uncertain sea-level response to anthropogenic climate change. The model consists of 'building blocks' that represent the major components of sea-level response and its uncertainties, including threshold behavior. The framework's simplicity enables the simulation of large ensembles allowing for an efficient exploration of parameter uncertainty and for the simulation of multiple combined adaptation and mitigation strategies. The model framework can skilfully reproduce earlier major sea level assessments, but due to the modular setup it can also be easily utilized to explore high-end scenarios and the effect of competing assumptions and parameterizations.

Plants Regulate Soil Organic Matter Decomposition in Response to Sea Level Rise

NASA Astrophysics Data System (ADS)

Megonigal, P.; Mueller, P.; Jensen, K.

2014-12-01

Tidal wetlands have a large capacity for producing and storing organic matter, making their role in the global carbon budget disproportionate to their land area. Most of the organic matter stored in these systems is in soils where it contributes 2-5 times more to surface accretion than an equal mass of minerals. Soil organic matter (SOM) sequestration is the primary process by which tidal wetlands become perched high in the tidal frame, decreasing their vulnerability to accelerated sea level rise. Plant growth responses to sea level rise are well understood and represented in century-scale forecast models of soil surface elevation change. We understand far less about the response of soil organic matter decomposition to rapid sea level rise. Here we quantified the effects of sea level on SOM decomposition rates by exposing planted and unplanted tidal marsh monoliths to experimentally manipulated flood duration. The study was performed in a field-based mesocosm facility at the Smithsonian's Global Change Research Wetland. SOM decomposition rate was quantified as CO2 efflux, with plant- and SOM-derived CO2 separated with a two end-member δ13C-CO2 model. Despite the dogma that decomposition rates are inversely related to flooding, SOM mineralization was not sensitive to flood duration over a 35 cm range in soil surface elevation. However, decomposition rates were strongly and positively related to aboveground biomass (R2≥0.59, p≤0.01). We conclude that soil carbon loss through decomposition is driven by plant responses to sea level in this intensively studied tidal marsh. If this result applies more generally to tidal wetlands, it has important implications for modeling soil organic matter and surface elevation change in response to accelerated sea level rise.

Formation and fate of sedimentary depocentres on Southeast Asia's Sunda Shelf over the past sea-level cycle and biogeographic implications

NASA Astrophysics Data System (ADS)

Hanebuth, Till J. J.; Voris, Harold K.; Yokoyama, Yusuke; Saito, Yoshiki; Okuno, Jun'ichi

2011-01-01

Sea-level variations are the major factor controlling sedimentation as well as the biogeographic patterns at continental margins over late Quaternary times. Fluctuations on millennial time-scales produce locally complex deposits in coasts and on shelves, associated with short-term influence on species development. This article reviews the sedimentary and biogeographic history of the tropical siliciclastic Sunda Shelf as an end-member of continental shelves regarding extreme width, an enormous sediment supply, and highest biodiversity in response to rapid sea-level fluctuations. We describe particular depositional segments as part of a genetic succession of zones from land to the deep sea based on literature data, field observations, and calculation of hydro-isostatic adjustment effects on changing relative sea level. These segments are characterized by individual sedimentary processes and deposits, and by a specific potential for material storage and re-mobilization. Long-term regressive intervals led to overall sigmoidal-promoting, extremely thick, and wide succeeding units. In contrast, rapid lateral shifts of defined depocentres over long distances took place in response to short-term sea level fluctuations. Fully isolated small-scale sediment bodies formed when sea level changed at exceptionally high rates. As a result of the high availability of organic-rich sediments, mangrove and freshwater peats formed frequently over late Quaternary times. The appearance of thick, massive and widespread peats is mainly linked to time intervals of a sea-level rise at slow rates, whilst organic matter appears much more dispersely in the sediments during episodes of rapidly changing sea level. The preservation potential of the regressive units is generally high due to highest initial sediment supply, stabilizing soil formation during exposure and rapid subsidence. Preservation of depositional elements from other periods is more exceptional and either restricted to local morphological depressions or to episodes of rapid sea level change. Besides complex channel incision, an overall lowering of the sediment surface related to erosion, as deep as 20 m or more, over wide areas took place mainly during sea level lowering. The final export of shelf material is documented by enormous mass-wasting packages on the associated continental slope. From a palaeogeographic perspective, the rapid formation or disappearance of special habitat zones, such as mangrove fringes and extended mud flats, led to species establishment or truncation in distribution. In addition, the opening or closure of ocean passages, as narrow bridges allowing limited species crossing or as fully colonized corridors, had severe impact on eco-fragmentation and the expansion or contraction of species. Independent of such particular conditions, sea-level changes have been too rapid over the past climatic cycle to allow full regeneration and mature development of coast-related ecosystems.

Estimating costs of sea lice control strategy in Norway.

PubMed

Liu, Yajie; Bjelland, Hans Vanhauwaer

2014-12-01

This paper explores the costs of sea lice control strategies associated with salmon aquaculture at a farm level in Norway. Diseases can cause reduction in growth, low feed efficiency and market prices, increasing mortality rates, and expenditures on prevention and treatment measures. Aquaculture farms suffer the most direct and immediate economic losses from diseases. The goal of a control strategy is to minimize the total disease costs, including biological losses, and treatment costs while to maximize overall profit. Prevention and control strategies are required to eliminate or minimize the disease, while cost-effective disease control strategies at the fish farm level are designed to reduce the losses, and to enhance productivity and profitability. Thus, the goal can be achieved by integrating models of fish growth, sea lice dynamics and economic factors. A production function is first constructed to incorporate the effects of sea lice on production at a farm level, followed by a detailed cost analysis of several prevention and treatment strategies associated with sea lice in Norway. The results reveal that treatments are costly and treatment costs are very sensitive to treatment types used and timing of the treatment conducted. Applying treatment at an early growth stage is more economical than at a later stage. Copyright © 2014 Elsevier B.V. All rights reserved.

A search for scale in sea-level studies

USGS Publications Warehouse

Larsen, C.E.; Clark, I.

2006-01-01

Many researchers assume a proportional relationship among the atmospheric CO2 concentration, temperature, and sea level. Thus, the rate of sea-level rise should increase in concert with the documented exponential increase in CO2. Although sea surface temperature has increased in places over the past century and short-term sea level rose abruptly during the 1990s, it is difficult to demonstrate a proportional relationship using existing geologic or historic records. Tide gauge records in the United States cover too short a time interval to verify acceleration in the rate of sea-level rise, although multicentury tide gauge and staff records from the Netherlands and Sweden suggest a mid-19th-century acceleration in sea-level rise. Reconstructions of sea-level changes for the past 1000 years derived using benthic foraminifer data from salt marshes along the East Coast of the United States suggest an increased rate of relative sea-level rise beginning in the 1600s. Geologic records of relative sea-level rise for the past 6000 years are available for several sites along the US East Coast from 14C-dated basal peat below salt marshes and estuarine sediments. When these three scales of sea-level variation are integrated, adjusted for postglacial isostatic movement, and replotted, the range of variation in sea level suggested by basal peat ages is within ??1 meter of the long-term trend. The reconstruction from Long Island Sound data shows a linear rise in sea level beginning in the mid-1600s at a rate consistent with the historic record of mean high water. Long-term tide gauge records from Europe and North America show similar trends since the mid-19th century. There is no clear proportional exponential increase in the rate of sea-level rise. If proportionality exists among sea level, atmospheric CO2, and temperature, there may be a significant time lag before an anthropogenic increase in the rate of sea-level rise occurs.

Variability and change of sea level and its components in the Indo-Pacific region during the altimetry era

NASA Astrophysics Data System (ADS)

Wu, Quran; Zhang, Xuebin; Church, John A.; Hu, Jianyu

2017-03-01

Previous studies have shown that regional sea level exhibits interannual and decadal variations associated with the modes of climate variability. A better understanding of those low-frequency sea level variations benefits the detection and attribution of climate change signals. Nonetheless, the contributions of thermosteric, halosteric, and mass sea level components to sea level variability and trend patterns remain unclear. By focusing on signals associated with dominant climate modes in the Indo-Pacific region, we estimate the interannual and decadal fingerprints and trend of each sea level component utilizing a multivariate linear regression of two adjoint-based ocean reanalyses. Sea level interannual, decadal, and trend patterns primarily come from thermosteric sea level (TSSL). Halosteric sea level (HSSL) is of regional importance in the Pacific Ocean on decadal time scale and dominates sea level trends in the northeast subtropical Pacific. The compensation between TSSL and HSSL is identified in their decadal variability and trends. The interannual and decadal variability of temperature generally peak at subsurface around 100 m but that of salinity tend to be surface-intensified. Decadal temperature and salinity signals extend deeper into the ocean in some regions than their interannual equivalents. Mass sea level (MassSL) is critical for the interannual and decadal variability of sea level over shelf seas. Inconsistencies exist in MassSL trend patterns among various estimates. This study highlights regions where multiple processes work together to control sea level variability and change. Further work is required to better understand the interaction of different processes in those regions.

Effects of sea-level rise on barrier island groundwater system dynamics: ecohydrological implications

USGS Publications Warehouse

Masterson, John P.; Fienen, Michael N.; Thieler, E. Robert; Gesch, Dean B.; Gutierrez, Benjamin T.; Plant, Nathaniel G.

2014-01-01

We used a numerical model to investigate how a barrier island groundwater system responds to increases of up to 60 cm in sea level. We found that a sea-level rise of 20 cm leads to substantial changes in the depth of the water table and the extent and depth of saltwater intrusion, which are key determinants in the establishment, distribution and succession of vegetation assemblages and habitat suitability in barrier islands ecosystems. In our simulations, increases in water-table height in areas with a shallow depth to water (or thin vadose zone) resulted in extensive groundwater inundation of land surface and a thinning of the underlying freshwater lens. We demonstrated the interdependence of the groundwater response to island morphology by evaluating changes at three sites. This interdependence can have a profound effect on ecosystem composition in these fragile coastal landscapes under long-term changing climatic conditions.

Heat increment of feeding in Steller sea lions, Eumetopias jubatus.

PubMed

Rosen, D A; Trites, A W

1997-11-01

The heat increment of feeding (HIF) was measured in six captive, juvenile Steller sea lions (Eumetopias jubatus), fed meals of either 2 or 4 kg of herring. HIF was calculated as the post-prandial increase in metabolism above baseline levels, and was measured using open-circuit (gas) respirometry. It averaged 12.4 +/- 0.9% (SE) of ingested energy intake for the 4-kg meal trials, and 9.9 +/- 0.9% for the 2-kg meal size. The effect lasted 8-10 hr for the larger meal size. Metabolism peaked 3.7 hr after feeding, and was 2.13 times higher than baseline levels. For the 2-kg meal size, the effect lasted 6-8 hr, with metabolism peaking 2.8 hr after ingestion at 1.76 times baseline levels. Our estimates of HIF for Steller sea lions are at the lower end of estimates for terrestrial mammals, and are consistent with estimates for other marine mammals.

Calculated effects of turbine rotor-blade cooling-air flow, altitude, and compressor bleed point on performance of a turbojet engine

NASA Technical Reports Server (NTRS)

Arne, Vernon L; Nachtigall, Alfred J

1951-01-01

Effects of air-cooling turbine rotor blades on performance of a turbojet engine were calculated for a range of altitudes from sea level to 40,000 feet and a range of coolant flows up to 3 percent of compressor air flow, for two conditions of coolant bleed from the compressor. Bleeding at required coolant pressure resulted in a sea-level thrust reduction approximately twice the percentage coolant flow and in an increase in specific fuel consumption approximately equal to percentage coolant flow. For any fixed value of coolant flow ratio the percentage thrust reduction and percentage increase in specific fuel consumption decreased with altitude. Bleeding coolant at the compressor discharge resulted in an additional 1 percent loss in performance at sea level and in smaller increase in loss of performance at higher altitudes.

Holocene sea-level changes in the Falkland Islands

NASA Astrophysics Data System (ADS)

Newton, Tom; Gehrels, Roland; Daley, Tim; Long, Antony; Bentley, Mike

2014-05-01

In many locations in the southern hemisphere, relative sea level (RSL) reached its maximum position during the middle Holocene. This highstand is used by models of glacial isostatic adjustment (GIA) to constrain the melt histories of the large ice sheets, particularly Antarctica. In this paper we present the first Holocene sea-level record from the Falkland Islands (Islas Malvinas), an archipelago located on the Patagonian continental shelf about 500 km east of mainland South America at a latitude of ca. 52 degrees. Unlike coastal locations in southernmost South America, Holocene sea-level data from the Falklands are not influenced by tectonics, local ice loading effects and large tidal ranges such that GIA and ice-ocean mass flux are the dominant drivers of RSL change. Our study site is a salt marsh located in Swan Inlet in East Falkland, around 50 km southwest of Stanley. This is the largest and best developed salt marsh in the Falkland Islands. Cores were collected in 2005 and 2013. Lithostratigraphic analyses were complemented by analyses of foraminifera, testate amoebae and diatoms to infer palaeoenvironments. The bedrock, a Permian black shale, is overlain by grey-brown organic salt-marsh clay, up to 90 cm thick, which, in a landward direction, is replaced by freshwater organic sediments. Overlying these units are medium-coarse sands with occasional pebbles, up to 115 cm thick, containing tidal flat foraminifera. The sandy unit is erosively overlain by a grey-brown organic salt-marsh peat which extends up to the present surface. Further away from the sea this unit is predominantly of freshwater origin. Based on 13 radiocarbon dates we infer that prior to ~9.5 ka sea level was several metres below present. Under rising sea levels a salt marsh developed which was suddenly drowned around 8.4 ka, synchronous with a sea-level jump known from northern hemisphere locations. Following the drowning, RSL rose to its maximum position around 7 ka, less than 0.5 m above present sea level. RSL then fell slowly during the middle and late Holocene, eroding the elevated tidal flat deposits in places, and allowing development of thin salt marsh deposits and encroachment of freshwater marsh. Our new sea-level index points are roughly in agreement with GIA model predictions but place tight constraints on the timing of early Holocene RSL rise and the height and timing of the maximum Holocene RSL position.

Analysis of present and future potential compound flooding risk along the European coast

NASA Astrophysics Data System (ADS)

Bevacqua, Emanuele; Maraun, Douglas; Voukouvalas, Evangelos; Vousdoukas, Michalis I.; Widmann, Martin; Manning, Colin; Vrac, Mathieu

2017-04-01

The coastal zone is the natural border between the sea and the mainland, and it is constantly under the influence of marine and land-based natural and human-induced pressure. Compound floods are extreme events occurring in coastal areas where the interaction of joint high sea level and large amount of precipitation causes extreme floodings. Typically the risk of flooding in coastal areas is defined analysing either sea level or precipitation driven floodings, however compound floods should be considered to avoid an underestimation of the risk. In the future, the human pressure at the coastal zone is expected to increase, urging for a comprehensive analysis of the compound flooding risk under different climate change scenarios. In this study we introduce the concept of "potential risk" as we investigate how often large amount of precipitation and high sea level may co-occur, and not the effective impact due to the interaction of these two hazards. The effective risk of compound flooding in a specific place depends also on the local orography and on the existing protections. The estimation of the potential risk of compound flooding is useful to individuate places where an effective risk of compound flooding may exist, and where further studies would be useful to get more precise information on the local risk. We estimate the potential risk of compound flooding along the European coastal zone incorporating the ERA-Interim meteorological reanalysis for the past and present state, and the future projections from two RCP scenarios (namely the RCP4.5 and RCP8.5 scenarios) as derived from 8 CMIP5 models of the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Sea level data are estimated by forcing the hydrodynamic model Delft3D-Flow with 6-hourly wind and atmospheric pressure fields. Based on sea level (storm surge and astronomical tide) and precipitation joint occurrence analysis, a map of the potential compound flooding risk along the European coast is proposed and critical places with high potential risk are identified. For these critical places, we plan to asses the potential compound flood risk driven by coinciding extreme values of sea level and river discharge. Finally, we analyse the atmospheric large scale processes that lead to compound floods and their variation under future climate change scenarios.

Absorption of flavonols derived from sea buckthorn (Hippophaë rhamnoides L.) and their effect on emerging risk factors for cardiovascular disease in humans.

PubMed

Suomela, Jukka-Pekka; Ahotupa, Markku; Yang, Baoru; Vasankari, Tommi; Kallio, Heikki

2006-09-20

Sea buckthorn (Hippophaë rhamnoides L.) is a rich source of flavonols, especially isorhamnetin. Most prospective cohort studies have indicated some degree of inverse association between flavonoid intake and coronary heart disease. Animal and human studies suggest that sea buckthorn flavonoids may scavenge free radicals, lower blood viscosity, and enhance cardiac function. The effects of flavonol aglycones derived from sea buckthorn on the risk factors of cardiovascular disease as well as their absorption were studied in humans. The flavonols, ingested with oatmeal porridge, did not have a significant effect on the levels of oxidized low-density lipoprotein, C-reactive protein, and homocysteine, on the plasma antioxidant potential, or on the paraoxonase activity. Flavonols at two dosages in oatmeal porridge were rapidly absorbed, and a relatively small amount of sea buckthorn oil added to the porridge seemed to have increased the bioavailability of sea buckthorn flavonols consumed at the higher dose.

Salinity of the Delaware Estuary

USGS Publications Warehouse

Cohen, Bernard; McCarthy, Leo T.

1962-01-01

The purpose of this investigation was to obtain data on and study the factors affecting the salinity of the Delaware River from Philadelphia, Pa., to the Appoquinimink River, Del. The general chemical quality of water in the estuary is described, including changes in salinity in the river cross section and profile, diurnal and seasonal changes, and the effects of rainfall, sea level, and winds on salinity. Relationships are established of the concentrations of chloride and dissolved solids to specific conductance. In addition to chloride profiles and isochlor plots, time series are plotted for salinity or some quantity representing salinity, fresh-water discharge, mean river level, and mean sea level. The two major variables which appear to have the greatest effect on the salinity of the estuary are the fresh-water flow of the river and sea level. The most favorable combination of these variables for salt-water encroachment occurs from August to early October and the least favorable combination occurs between December and May.

Stratigraphic controls on seawater intrusion and implications for groundwater management, Dominguez Gap area of Los Angeles, California, USA

USGS Publications Warehouse

Nishikawa, T.; Siade, A.J.; Reichard, E.G.; Ponti, D.J.; Canales, A.G.; Johnson, T.A.

2009-01-01

Groundwater pumping has led to extensive water-level declines and seawater intrusion in coastal Los Angeles, California (USA). A SUTRA-based solute-transport model was developed to test the hydraulic implications of a sequence-stratigraphic model of the Dominguez Gap area and to assess the effects of water-management scenarios. The model is two-dimensional, vertical and follows an approximate flow line extending from the Pacific Ocean through the Dominguez Gap area. Results indicate that a newly identified fault system can provide a pathway for transport of seawater and that a stratigraphic boundary located between the Bent Spring and Upper Wilmington sequences may control the vertical movement of seawater. Three 50-year water-management scenarios were considered: (1) no change in water-management practices; (2) installation of a slurry wall; and (3) raising inland water levels to 7.6 m above sea level. Scenario 3 was the most effective by reversing seawater intrusion. The effects of an instantaneous 1-m sea-level rise were also tested using water-management scenarios 1 and 3. Results from two 100-year simulations indicate that a 1-m sea-level rise may accelerate seawater intrusion for scenario 1; however, scenario 3 remains effective for controlling seawater intrusion. ?? Springer-Verlag 2009.

Sedimentation and belowground carbon accumulation rates in mangrove forests that differ in diversity and land use: a tale of two mangroves

Treesearch

Richard A. MacKenzie; Patra B. Foulk; J. Val Klump; Kimberly Weckerly; Joko Purbospito; Daniel Murdiyarso; Daniel C. Donato; Vien Ngoc Nam

2016-01-01

Increased sea level is the climate change effect expected to have the greatest impact on mangrove forest survival. Mangroves have survived extreme fluctuations in sea level in the past through sedimentation and belowground carbon (C) accumulation, yet it is unclear what factors may influence these two parameters. We measured sedimentation, vertical accretion, and...

Modelling the thermosteric contribution to global and regional sea-level rise during the last interglacial

NASA Astrophysics Data System (ADS)

Singarayer, Joy; Stone, Emma; Whipple, Matthew; Lunt, Dan; Bouttes, Nathaelle; Gregory, Jonathan

2014-05-01

Global sea level during the last interglacial is likely to have been between 5.5 and 9m above present (Dutton and Lambeck, 2012). Recent calculations, taking into account latest NEEM ice core information, suggest that Greenland would probably not have contributed more than 2.2m to this (Stone et al, 2013), implying a considerable contribution from Antarctica. Previous studies have suggested a significant loss from the West Antarctic ice-sheet (e.g. Holden et al, 2010), which could be initiated following a collapse of the Atlantic Meridional Overturning Circulation (AMOC) and resultant warming in the Southern Ocean. Here, model simulations with FAMOUS and HadCM3 have been performed of the last interglacial under various scenarios of reduced Greenland and Antarctic ice-sheet configurations, and with and without collapsed AMOC. Thermal expansion and changes in regional density structure (resulting from ocean circulation changes) can also influence sea level, in addition to ice mass effects discussed thus far. The HadCM3 and FAMOUS simulations will be used to estimate the contribution to global and regional sea level change in interglacials from the latter two factors using a similar methodology to the IPCC TAR/AR4 estimations of future sea level rise (Gregory and Lowe, 2000). The HadCM3 and FAMOUS both have a rigid lid in their ocean model, and consequently a fixed ocean volume. Thermal expansion can, however, be calculated as a volume change from in-situ density (a prognostic variable from the model). Relative sea surface topography will then be estimated from surface pressure gradients and changes in atmospheric pressure. Dutton A., and Lambeck K., 2013. Ice Volume and Sea Level During the Last Interglacial. Science, 337, 216-219 Gregory J.M. and Lowe J.A., 2000. Predictions of global and regional sea-level using AOGCMs with and without flux adjustment. GRL, 27, 3069-3072 Holden P. et al., 2010. Interhemispheric coupling, the West Antarctic Ice Sheet and warm Antarctic interglacials. Clim. Past, 6, 431-443 Stone E.J., et al., 2013. Quantification of the Greenland ice sheet contribution to Last Interglacial sea level rise. Clim. Past, 9, 621-639

Prediction and explanation of increases of mean sea levels in northern hemisphere, in southern hemisphere and all ocean of the Earth

NASA Astrophysics Data System (ADS)

Barkin, Yu. V.

2009-04-01

The phenomenon of contrast secular changes of sea levels in the southern and northern hemispheres, predicted on the basis of geodynamic model about the forced relative oscillations and displacements of the Earth shells, has obtained theoretical explanation. In northern hemisphere the mean sea level of ocean increases with velocity about 2.45±0.32 mm/yr, and in a southern hemisphere the mean sea level increases with velocity about 0.67±0.30 mm/yr. Theoretical values of velocity of increase of global mean sea level thus has been estimated in 1.61±0.36 mm/yr. 1 Introduction. The slow (secular) drift of the centre of mass of the Earth in the direction of North Pole with velocity about 12-20 mm/yr has been predicted by author in 1995, and now has confirmed with methods of space geodesy. The DORIS data in period 1999-2008 let us to estimate velocity of polar drift in 5.24 ± 0.29 mm/yr. To explain this fundamental planetary phenomenon it is possible only, having admitted, that similar northern drift tests the centre of mass of the liquid core relatively to the centre of mass of viscous-elastic and thermodynamically changeable mantle with velocity about 2-3 cm/yr [1]. Naturally, a drift of the core is accompanied by the global changes (deformations) of all layers of the mantle and the core, by inversion changes of their tension states when in one hemisphere the tension increases and opposite on the contrary - decreases. Also it is possible that thermodynamical mechanism actively works with inversion properties of molting and solidification of materials at core-mantle boundary in opposite (northern - southern) hemispheres. 2 Atmospheric and oceanic inversion tides. The gravitational attraction of superfluous mass of the drifting to the North core (in 17 masses of the Moon) causes a planetary inversion tide of air masses of the Earth and its oceanic masses, from the southern hemisphere - to the northern hemisphere [2, 3]. As consequence the phenomenon of increasing of bottom pressure in the northern ocean must be observed, and in the southern ocean - decreasing. By our theoretical estimations the mean atmospheric pressure in the northern hemisphere accrues with velocity about 0.17 mbar/yr and with similar negative velocity in southern hemisphere. The predicted phenomenon of a slow redistribution of air masses from the southern hemisphere in northern has already obtained a partially confirmation according to the meteorological observations [4]: 0.17-0.22 mbar/yr (northern hemisphere) and -0.18 mbar/yr (southern hemisphere). In the report the mechanisms of the revealed phenomena, their dynamic interrelation are discussed and an possible interpretation to the data of observations is given. 3 Contrast changes of mean sea levels in northern and southern hemispheres. The air masses slowly are transported from a southern hemisphere in northern. They form an original inversion secular atmospheric tide which existence proves to be true by the modern data of observations [4]. The gravitational attraction of the core which is displaced along a polar axis causes the similar tide of oceanic masses [2]. The barometric effect of influence of atmospheric tide will result in reduction of expected secular oceanic tide. Really, an increase of mean atmospheric pressure in the northern hemisphere results in replacement of oceanic masses in the southern hemisphere. Only for this reason the mean sea level in the northern hemisphere decreases with secular velocity -1.98 mm/yr. In turn a decrease of atmospheric pressure in the southern hemisphere results in an increase of the mean sea level in this hemisphere with velocity 1.43 mm/yr. Preliminary estimations have shown, that a oceanic inversion tide, caused by a gravitational attraction of the drifting core, gives the basic contribution to the phenomenon of secular variation of the mean sea level in N and S hemispheres (in northern hemisphere the mean sea level increases with velocity 3.01±0.17 mm/yr and in the southern hemisphere it decreases with velocity -2.18±0.12 mm/yr). Taking into account now both described phenomena, we come to a conclusion, that velocity of increase of the mean sea level in northern hemisphere makes 1.03 mm/yr. The velocity of decrease of the sea level in the southern hemisphere (because of influence of the specified two factors) is estimated in -0.75 mm/yr. On the sea level the slow deformation changes of a bottom of the ocean render the essential influence. This tectonic phenomenon is connected with global (planetary) changes of shapes of hemispheres of the Earth. The last have been predicted and described on the basis of developed geodynamic model and revealed by methods of space geodesy (Barkin, Jin, 2007). On the basis of these results the estimation of velocity of increase of the mean sea level because of deformations of ocean bottom in 0.55±0.26 mm/yr has been obtained. An analysis has shown that thermal factors play big role in secular change of sea level (global and in hemispheres). Here we will accept conclusions of the last years that due to a heating of ocean layers and their expansion and due to melting of glaciers and other contributions of water masses in ocean its mean sea level rises with velocity about 0.83 mm/yr. Summarizing now all considered factors of increase of the sea level, we come to the important conclusion. In northern hemisphere the mean sea level of ocean increases with velocity about 2.45±0.32 mm/yr, and in a southern hemisphere the mean sea level increases with velocity about 0.67±0.30 mm/yr. Theoretical values of velocity of increase of global mean sea level of ocean thus has been estimated in 1.61±0.36 mm/yr. Observations on the coastal guage stations confirm these theoretical values. 4 Explanation of altimetry observations. An altimetry mehod can not give obtained above values of velocities of increasing of mean sea levels in northern and in southern hemispheres and of course and real value for global change. The reason consists that altimetry determinations include additional effect, we shall name it is fictitious, which is caused by secular drift of the centre of mass of the Earth to the North with velocity 5.24±0.29 mm/yr. It is uneasy to show, that only one effect of drift of the centre of mass results in fictitious effect of decreasing of mean sea level in northern hemisphere with velocity -2.37±0.13 mm/yr and to increasing of the mean sea level in a southern hemisphere with velocity 2.66±0.15 mm/yr, and also to effect of increase of mean global sea level with velocity 0.54±0.03 mm/yr. And the specified effects would take a place in observations even if the real sea level would not vary at all. But we shall add real values of velocities obtained above to fictitious and we shall obtain, accordingly, the values of velocities which can be obtained by altimetry method at scope by observations of all latitudes of ocean areas: 0.08 mm/yr for northern hemisphere; 3.33±0.30 mm/yr for southern hemisphere and 2.15 ±0.39 mm/yr for a global level of ocean. But they have not any relation to real characteristics of change of sea levels in northern and southern hemispheres of the Earth and to its global secular change. Real values of N-S-G velocities of increase of mean sea levels in northern hemisphere, in a southern hemisphere and all ocean make: 2.45±0.32 mm/yr, 0.67±0.30 mm/yr and 1.61±0.36 mm/yr. The offered model and theoretical constructions allow to explain and to understand more deeply the most difficult effects in behavior of ocean in northern and southern hemispheres of the Earth. The obtained values of velocities of change of mean N-S-G sea levels have been obtained at set of simplifying assumptions concerning of a direction of drift of the centre of mass of the Earth and character of redistribution of atmospheric and oceanic masses and, naturally, in the future will be specified. The work was accepted by grants of RFBR: N 07-05-00939 and N 09-05-92507. References [1] Barkin Yu.V. (2002) An explanation of endogenous activity of planets and satellites and its cyclisity, Isvestia sekcii nauk o Zemle Rossiiskoi akademii ectestvennykh nauk, Vyp. 9, M., VINITI, 45-97. In Russian. [2] Barkin Yu.V. (2005) Oscillations of the Earth core, new oceanic tides and dynamical consequences. Materials of XI International Scientific Conference "Structure, geodynamics and mineral genetic processes in lithosphere" (September, 20-22 2005, Syktyvkar, Russia), Publisher of Geology Institute of Komi SC of Ural Section of RAS, Syktyvkar, pp. 26-28. In Russian. [3] Barkin Yu.V. (2007) Forced redistribution of air masses between southern and northern hemispheres of the Earth. Proceedings of IUGG XXIV General Assembly, Perugia, Italy 2007: Earth: Our Changing Planet (Perugia, Italy, July 2-13, 2007), (A)-IAGA, JAS008, p. 326. www. iugg2007perugia.it. [4] Burlutsky R.F. Determination of the global concentration of pair on the ground pressure. Materials of Sagitov's readings. M., SAI, MSU, 2007, www.sai.msu.ru.

Monitoring Sea Level in the Coastal Zone with Satellite Altimetry and Tide Gauges

NASA Astrophysics Data System (ADS)

Cipollini, Paolo; Calafat, Francisco M.; Jevrejeva, Svetlana; Melet, Angelique; Prandi, Pierre

2017-01-01

We examine the issue of sustained measurements of sea level in the coastal zone, first by summarizing the long-term observations from tide gauges, then showing how those are now complemented by improved satellite altimetry products in the coastal ocean. We present some of the progresses in coastal altimetry, both from dedicated reprocessing of the radar waveforms and from the development of improved corrections for the atmospheric effects. This trend towards better altimetric data at the coast comes also from technological innovations such as Ka-band altimetry and SAR altimetry, and we discuss the advantages deriving from the AltiKa Ka-band altimeter and the SIRAL altimeter on CryoSat-2 that can be operated in SAR mode. A case study along the UK coast demonstrates the good agreement between coastal altimetry and tide gauge observations, with root mean square differences as low as 4 cm at many stations, allowing the characterization of the annual cycle of sea level along the UK coasts. Finally, we examine the evolution of the sea level trend from the open to the coastal ocean along the western coast of Africa, comparing standard and coastally improved products. Different products give different sea level trend profiles, so the recommendation is that additional efforts are needed to study sea level trends in the coastal zone from past and present satellite altimeters. Further improvements are expected from more refined processing and screening of data, but in particular from the constant improvements in the geophysical corrections.

Current state and future perspectives on coupled ice-sheet - sea-level modelling

NASA Astrophysics Data System (ADS)

de Boer, Bas; Stocchi, Paolo; Whitehouse, Pippa L.; van de Wal, Roderik S. W.

2017-08-01

The interaction between ice-sheet growth and retreat and sea-level change has been an established field of research for many years. However, recent advances in numerical modelling have shed new light on the precise interaction of marine ice sheets with the change in near-field sea level, and the related stability of the grounding line position. Studies using fully coupled ice-sheet - sea-level models have shown that accounting for gravitationally self-consistent sea-level change will act to slow down the retreat and advance of marine ice-sheet grounding lines. Moreover, by simultaneously solving the 'sea-level equation' and modelling ice-sheet flow, coupled models provide a global field of relative sea-level change that is consistent with dynamic changes in ice-sheet extent. In this paper we present an overview of recent advances, possible caveats, methodologies and challenges involved in coupled ice-sheet - sea-level modelling. We conclude by presenting a first-order comparison between a suite of relative sea-level data and output from a coupled ice-sheet - sea-level model.

Robustness of observation-based decadal sea level variability in the Indo-Pacific Ocean

NASA Astrophysics Data System (ADS)

Nidheesh, A. G.; Lengaigne, M.; Vialard, J.; Izumo, T.; Unnikrishnan, A. S.; Meyssignac, B.; Hamlington, B.; de Boyer Montegut, C.

2017-07-01

We examine the consistency of Indo-Pacific decadal sea level variability in 10 gridded, observation-based sea level products for the 1960-2010 period. Decadal sea level variations are robust in the Pacific, with more than 50% of variance explained by decadal modulation of two flavors of El Niño-Southern Oscillation (classical ENSO and Modoki). Amplitude of decadal sea level variability is weaker in the Indian Ocean than in the Pacific. All data sets indicate a transmission of decadal sea level signals from the western Pacific to the northwest Australian coast through the Indonesian throughflow. The southern tropical Indian Ocean sea level variability is associated with decadal modulations of ENSO in reconstructions but not in reanalyses or in situ data set. The Pacific-independent Indian Ocean decadal sea level variability is not robust but tends to be maximum in the southwestern tropical Indian Ocean. The inconsistency of Indian Ocean decadal variability across the sea level products calls for caution in making definitive conclusions on decadal sea level variability in this basin.

New evidence for "far-field" Holocene sea level oscillations and links to global climate records

NASA Astrophysics Data System (ADS)

Leonard, N. D.; Welsh, K. J.; Clark, T. R.; Feng, Y.-x.; Pandolfi, J. M.; Zhao, J.-x.

2018-04-01

Rising sea level in the coming century is of significant concern, yet predicting relative sea level change in response to eustatic sea level variability is complex. Potential analogues are provided by the recent geological past but, until recently, many sea level reconstructions have been limited to millennial scale interpretations due to age uncertainties and paucity in proxy derived records. Here we present a sea level history for the tectonically stable "far-field" Great Barrier Reef, Australia, derived from 94 high precision uranium-thorium dates of sub-fossil coral microatolls. Our results provide evidence for at least two periods of relative sea level instability during the Holocene. These sea level oscillations are broadly synchronous with Indo-Pacific negative sea surface temperature anomalies, rapid global cooling events and glacial advances. We propose that the pace and magnitude of these oscillations are suggestive of eustatic/thermosteric processes operating in conjunction with regional climatic controls.

An extreme event of sea-level rise along the Northeast Coast of North America in 2009-2010.

PubMed

Goddard, Paul B; Yin, Jianjun; Griffies, Stephen M; Zhang, Shaoqing

2015-02-24

The coastal sea levels along the Northeast Coast of North America show significant year-to-year fluctuations in a general upward trend. The analysis of long-term tide gauge records identified an extreme sea-level rise (SLR) event during 2009-10. Within this 2-year period, the coastal sea level north of New York City jumped by 128 mm. This magnitude of interannual SLR is unprecedented (a 1-in-850 year event) during the entire history of the tide gauge records. Here we show that this extreme SLR event is a combined effect of two factors: an observed 30% downturn of the Atlantic meridional overturning circulation during 2009-10, and a significant negative North Atlantic Oscillation index. The extreme nature of the 2009-10 SLR event suggests that such a significant downturn of the Atlantic overturning circulation is very unusual. During the twenty-first century, climate models project an increase in magnitude and frequency of extreme interannual SLR events along this densely populated coast.

Sea-level rise induced amplification of coastal protection design heights.

PubMed

Arns, Arne; Dangendorf, Sönke; Jensen, Jürgen; Talke, Stefan; Bender, Jens; Pattiaratchi, Charitha

2017-01-06

Coastal protection design heights typically consider the superimposed effects of tides, surges, waves, and relative sea-level rise (SLR), neglecting non-linear feedbacks between these forcing factors. Here, we use hydrodynamic modelling and multivariate statistics to show that shallow coastal areas are extremely sensitive to changing non-linear interactions between individual components caused by SLR. As sea-level increases, the depth-limitation of waves relaxes, resulting in waves with larger periods, greater amplitudes, and higher run-up; moreover, depth and frictional changes affect tide, surge, and wave characteristics, altering the relative importance of other risk factors. Consequently, sea-level driven changes in wave characteristics, and to a lesser extent, tides, amplify the resulting design heights by an average of 48-56%, relative to design changes caused by SLR alone. Since many of the world's most vulnerable coastlines are impacted by depth-limited waves, our results suggest that the overall influence of SLR may be greatly underestimated in many regions.

Application of wet waste from shrimp ( Litopenaeus vannamei) with or without sea mud to feeding sea cucumber ( Stichopus monotuberculatus)

NASA Astrophysics Data System (ADS)

Chen, Yanfeng; Hu, Chaoqun; Ren, Chunhua

2015-02-01

In the present study, the applicability of the wet waste collected from shrimp ( Litopenaeus vannamei) to the culture of sea cucumber ( Stichopus monotuberculatus) was determined. The effects of dietary wet shrimp waste on the survival, specific growth rate (SGR), fecal production rate (FPR), ammonia- and nitrite-nitrogen productions of sea cucumber were studied. The total organic matter (TOM) level in the feces of sea cucumber was compared with that in corresponding feeds. Diet C (50% wet shrimp waste and 50% sea mud mash) made sea cucumber grow faster than other diets. Sea cucumber fed with either diet D (25% wet shrimp waste and 75% sea mud mash) or sole sea mud exhibited negative growth. The average lowest total FPR of sea cucumber occurred in diet A (wet shrimp waste), and there was no significant difference in total FPR between diet C and diet E (sea mud mash) ( P > 0.05). The average ammonia-nitrogen production of sea cucumber in different diet treatments decreased gradually with the decrease of crude protein content in different diets. The average highest nitrite-nitrogen production occurred in diet E treatment, and there was no significant difference in nitrite-nitrogen production among diet A, diet B (75% wet shrimp waste and 25% sea mud mash) and diet C treatments ( P > 0.05). In each diet treatment, the total organic matter (TOM) level in feces decreased to different extent compared with that in corresponding feeds.

Gulf Coast vulnerability assessment: Mangrove, tidal emergent marsh, barrier islands and oyster reef

USGS Publications Warehouse

Watson, Amanda; Reece, Joshua; Tirpak, Blair; Edwards, Cynthia Kallio; Geselbracht, Laura; Woodrey, Mark; LaPeyre, Megan K.; Dalyander, Patricia (Soupy)

2017-01-01

Climate, sea level rise, and urbanization are undergoing unprecedented levels of combined change and are expected to have large effects on natural resources—particularly along the Gulf of Mexico coastline (Gulf Coast). Management decisions to address these effects (i.e., adaptation) require an understanding of the relative vulnerability of various resources to these stressors. To meet this need, the four Landscape Conservation Cooperatives along the Gulf partnered with the Gulf of Mexico Alliance to conduct this Gulf Coast Vulnerability Assessment (GCVA). Vulnerability in this context incorporates exposure and sensitivity to threats (potential impact), coupled with the adaptive capacity to mitigate those threats. Potential impact and adaptive capacity reflect natural history features of target species and ecosystems. The GCVA used an expert opinion approach to qualitatively assess the vulnerability of four ecosystems: mangrove, oyster reef, tidal emergent marsh, and barrier islands, and a suite of wildlife species that depend on them. More than 50 individuals participated in the completion of the GCVA, facilitated via Ecosystem and Species Expert Teams. Of the species assessed, Kemp’s ridley sea turtle was identified as the most vulnerable species across the Gulf Coast. Experts identified the main threats as loss of nesting habitat to sea level rise, erosion, and urbanization. Kemp’s ridley also had an overall low adaptive capacity score due to their low genetic diversity, and higher nest site fidelity as compared to other assessed species. Tidal emergent marsh was the most vulnerable ecosystem, due in part to sea level rise and erosion. In general, avian species were more vulnerable than fish because of nesting habitat loss to sea level rise, erosion, and potential increases in storm surge. Assessors commonly indicated a lack of information regarding impacts due to projected changes in the disturbance regime, biotic interactions, and synergistic effects in both the species and habitat assessments. Many of the assessors who focused on species also identified data gaps regarding genetic information, phenotypic plasticity, life history, and species responses to past climate change and sea level rise. Regardless of information gaps, the results from the GCVA can be used to inform Gulf-wide adaptation plans. Given the scale of climatic impacts, coordinated efforts to address Gulf-wide threats to species and ecosystems will enhance the effectiveness of management actions and also have the potential to maximize the efficacy of limited funding.

The Gulf Coast Vulnerability Assessment: Mangrove, Tidal Emergent Marsh, Barrier Islands, and Oyster Reef

USGS Publications Warehouse

Watson, Amanda; Reece, Joshua S.; Tirpak, Blair; Edwards, Cynthia Kallio; Geselbracht, Laura; Woodrey, Mark; LaPeyre, Megan K.; Dalyander, P. Soupy

2015-01-01

Climate, sea level rise, and urbanization are undergoing unprecedented levels of combined change and are expected to have large effects on natural resources—particularly along the Gulf of Mexico coastline (Gulf Coast). Management decisions to address these effects (i.e., adaptation) require an understanding of the relative vulnerability of various resources to these stressors. To meet this need, the four Landscape Conservation Cooperatives along the Gulf partnered with the Gulf of Mexico Alliance to conduct this Gulf Coast Vulnerability Assessment (GCVA). Vulnerability in this context incorporates the aspects of exposure and sensitivity to threats, coupled with the adaptive capacity to mitigate those threats. Potential impact and adaptive capacity reflect natural history features of target species and ecosystems. The GCVA used an expert opinion approach to qualitatively assess the vulnerability of four ecosystems: mangrove, oyster reef, tidal emergent marsh, and barrier islands, and a suite of wildlife species that depend on them. More than 50 individuals participated in the completion of the GCVA, facilitated via Ecosystem and Species Expert Teams. Of the species assessed, Kemp’s ridley sea turtle was identified as the most vulnerable species across the Gulf Coast. Experts identified the main threats as loss of nesting habitat to sea level rise, erosion, and urbanization. Kemp’s ridley also had an overall low adaptive capacity score due to their low genetic diversity, and higher nest site fidelity as compared to other assessed species. Tidal emergent marsh was the most vulnerable ecosystem, due in part to sea level rise and erosion. In general, avian species were more vulnerable than fish because of nesting habitat loss to sea level rise, erosion, and potential increases in storm surge. Assessors commonly indicated a lack of information regarding impacts due to projected changes in the disturbance regime, biotic interactions, and synergistic effects in both the species and habitat assessments. Many of the assessors who focused on species also identified data gaps regarding genetic information, phenotypic plasticity, life history, and species responses to past climate change and sea level rise. Regardless of information gaps, the results from the GCVA can be used to inform Gulf-wide adaptation plans. Given the scale of climatic impacts, coordinated efforts to address Gulf-wide threats to species and ecosystems will enhance the effectiveness of management actions and also have the potential to maximize the efficacy of limited funding.

Were sea level changes during the Pleistocene in the South Atlantic Coastal Plain a driver of speciation in Petunia (Solanaceae)?

PubMed

Ramos-Fregonezi, Aline M C; Fregonezi, Jeferson N; Cybis, Gabriela B; Fagundes, Nelson J R; Bonatto, Sandro L; Freitas, Loreta B

2015-05-20

Quaternary climatic changes led to variations in sea level and these variations played a significant role in the generation of marine terrace deposits in the South Atlantic Coastal Plain. The main consequence of the increase in sea level was local extinction or population displacement, such that coastal species would be found around the new coastline. Our main goal was to investigate the effects of sea level changes on the geographical structure and variability of genetic lineages from a Petunia species endemic to the South Atlantic Coastal Plain. We employed a phylogeographic approach based on plastid sequences obtained from individuals collected from the complete geographic distribution of Petunia integrifolia ssp. depauperata and its sister group. We used population genetics tests to evaluate the degree of genetic variation and structure among and within populations, and we used haplotype network analysis and Bayesian phylogenetic methods to estimate divergence times and population growth. We observed three major genetic lineages whose geographical distribution may be related to different transgression/regression events that occurred in this region during the Pleistocene. The divergence time between the monophyletic group P. integrifolia ssp. depauperata and its sister group (P. integrifolia ssp. integrifolia) was compatible with geological estimates of the availability of the coastal plain. Similarly, the origin of each genetic lineage is congruent with geological estimates of habitat availability. Diversification of P. integrifolia ssp. depauperata possibly occurred as a consequence of the marine transgression/regression cycles during the Pleistocene. In periods of high sea level, plants were most likely restricted to a refuge area corresponding to fossil dunes and granitic hills, from which they colonized the coast once the sea level came down. The modern pattern of lineage geographical distribution and population variation was established by a range expansion with serial founder effects conditioned on soil availability.

Integrating Thematic Web Portal Capabilities into the NASA Earthdata Web Infrastructure

NASA Technical Reports Server (NTRS)

Wong, Minnie; Baynes, Kathleen E.; Huang, Thomas; McLaughlin, Brett

2015-01-01

This poster will present the process of integrating thematic web portal capabilities into the NASA Earth data web infrastructure, with examples from the Sea Level Change Portal. The Sea Level Change Portal will be a source of current NASA research, data and information regarding sea level change. The portal will provide sea level change information through articles, graphics, videos and animations, an interactive tool to view and access sea level change data and a dashboard showing sea level change indicators.

A new Arctic 25-year Altimetric Sea-level Record (1992-2016) and Initial look at Arctic Sea Level Budget Closure

NASA Astrophysics Data System (ADS)

Andersen, O. B.; Passaro, M.; Benveniste, J.; Piccioni, G.

2016-12-01

A new initiative within the ESA Sea Level Climate Change initiative (SL-cci) framework to improve the Arctic sea level record has been initiated as a combined effort to reprocess and retrack past altimetry to create a 25-year combined sea level record for sea level research studies. One of the objectives is to retracked ERS-2 dataset for the high latitudes based on the ALES retracking algorithm through adapting the ALES retracker for retracking of specular surfaces (leads). Secondly a reprocessing using tailored editing to Arctic Conditions will be carried out also focusing on the merging of the multi-mission data. Finally an effort is to combine physical and empirical retracked sea surface height information to derive an experimental spatio-temporal enhanced sea level product for high latitude. The first results in analysing Arctic Sea level variations on annual inter-annual scales for the 1992-2015 from a preliminar version of this dataset is presented. By including the GRACE water storage estimates and NOAA halo- and thermo-steric sea level variatios since 2002 a preliminary attempt to close the Arctic Sea level budget is presented here. Closing the Arctic sea level budget is by no mean trivial as both steric data and satellite altimetry is both sparse temporally and limited geographically.

The end-Permian regression in the western Tethys: sedimentological and geochemical evidence from offshore the Persian Gulf, Iran

NASA Astrophysics Data System (ADS)

Tavakoli, Vahid; Naderi-Khujin, Mehrangiz; Seyedmehdi, Zahra

2018-04-01

Detailed sedimentological and geochemical records across the Permian-Triassic boundary (PTB) in five offshore wells of the central Persian Gulf served to interpret the end-Permian sea-level change in this region. A decrease in sea level at the PTB was established by petrographical and geochemical study of the boundary. Thin sections showed that Upper Permian strata are composed of dolomite with minor anhydrite, changing into limestone in Lower Triassic sediments. Brine dilution toward the boundary supports sea-level fall in the Permian-Triassic transition, reflected by a decrease in anhydrite content and a shallowing-upward trend from lagoonal to peritidal facies. Isotopic changes at the boundary are in favor of sea-level fall. Changes in both carbon (from about 4 to -1‰) and oxygen (from 2 to -5‰) stable isotopes show negative excursions. The shift in carbon isotope values is a global phenomenon and is interpreted as resulting from carbonate sediment interaction with 12C-rich waters at the end-Permian sea-level fall. However, the oxygen isotope shift is attributed to the effect of meteoric waters with negative oxygen isotope values. The increase in strontium isotope ratios is also consistent with the high rate of terrestrial input at the boundary. The effect of meteoric conditions during diagenesis is evident from vuggy and moldic porosities below the PTB. The following transgression at the base of the Triassic is evident from the presence of reworked fossils and intraclasts resulting from deposition from agitated water.

Experimental Investigation of River Avulsion and Land-Loss on a Backwater-Influenced Delta Undergoing Sea Level Rise

NASA Astrophysics Data System (ADS)

Sikes, K.; Chadwick, A. J.; Lamb, M. P.; Fuller, B. M.

2016-12-01

Predicting the frequency of river channel avulsions and the rate of land-loss on deltas is important for hazard mitigation, ecological protection, and coastal sustainability, especially given modern rates of relative sea level rise. Previous work has investigated the effect of hydrodynamic backwater in mediating sedimentation patterns and channel avulsions on deltas, but the effect of sea-level rise on backwater-influenced deltas has yet to be explored in experiments. We will present preliminary results from a flume experiment designed to explore the role of sea-level rise on the evolution of a backwater-mediated delta. The experiment was conducted in the river-ocean facility at Caltech, where a 7m long, 14cm wide alluvial river drains into a 6m by 3m "ocean" basin under subcritical flow conditions. We used periodic flood events with different discharges to produce persistent non-uniform flow with a backwater length of 1m. Using a combination of image processing and topographic scans, we will characterize the frequency of backwater-mediated avulsions and the evolution of discrete deltaic lobes under a series of steady sea-level rise rates of different magnitude. We predict that, under moderate rise rates, enhanced aggradation will cause channels to avulse at an accelerated pace, replenishing inactive lobes more quickly and naturally acting to mitigate the extent of drowning along the delta shoreline. However, for higher rise rates, we hypothesize that rapid shoreline retreat may shift the backwater zone upstream, leading to the complete abandonment of deltaic lobes.

Red Maca (Lepidium meyenii), a Plant from the Peruvian Highlands, Promotes Skin Wound Healing at Sea Level and at High Altitude in Adult Male Mice.

PubMed

Nuñez, Denisse; Olavegoya, Paola; Gonzales, Gustavo F; Gonzales-Castañeda, Cynthia

2017-12-01

Nuñez, Denisse, Paola Olavegoya, Gustavo F. Gonzales, and Cynthia Gonzales-Castañeda. Red maca (Lepidium meyenii), a plant from the Peruvian highlands, promotes skin wound healing at sea level and at high altitude in adult male mice. High Alt Med Biol 18:373-383, 2017.-Wound healing consists of three simultaneous phases: inflammation, proliferation, and remodeling. Previous studies suggest that there is a delay in the healing process in high altitude, mainly due to alterations in the inflammatory phase. Maca (Lepidium meyenii) is a Peruvian plant with diverse biological properties, such as the ability to protect the skin from inflammatory lesions caused by ultraviolet radiation, as well as its antioxidant and immunomodulatory properties. The aim of this study was to determine the effect of high altitude on tissue repair and the effect of the topical administration of the spray-dried extract of red maca (RM) in tissue repair. Studies were conducted in male Balb/c mice at sea level and high altitude. Lesions were inflicted through a 10 mm-diameter excisional wound in the skin dorsal surface. Treatments consisted of either (1) spray-dried RM extract or (2) vehicle (VH). Animals wounded at high altitude had a delayed healing rate and an increased wound width compared with those at sea level. Moreover, wounding at high altitude was associated with an increase in inflammatory cells. Treatment with RM accelerated wound closure, decreased the level of epidermal hyperplasia, and decreased the number of inflammatory cells at the wound site. In conclusion, RM at high altitude generate a positive effect on wound healing, decreasing the number of neutrophils and increasing the number of macrophages in the wound healing at day 7 postwounding. This phenomenon is not observed at sea level.

Identification of Individual Efficiency for Barometric Pressure and Ocean Tide Load Simultaneously Acted on Deep Aquifers Adjacent to the West Pacific Ocean

NASA Astrophysics Data System (ADS)

Shih, David Ching-Fang

2018-06-01

Groundwater fluctuation usually reflects the property of aquifer in nature. Actually, water level change can be caused not only by barometric pressure changes resulted from atmospheric motion, but also by the tidal effect from nearby marine system or water body. In confined aquifer, an increase in barometric pressure usually will cause a decrease in water level in well to an amount described by the barometric efficiency. The barometric efficiency can be also used as a correction factor to remove barometric effects on water levels in wells during an aquifer test. With the rise of the tidal sea on the coastal aquifer, it indicates that there will be compensating increases of water pressure and stress in the skeleton of aquifer. External forcing on groundwater level in the coastal aquifer, such as barometric effect and tidal sea, usually affect the water level to fluctuate with different phases to some extent. An adaptive adjustment to remove the combination of barometric and oceanic tidal efficiency is presented in this study. This research suggests that the presented formula can simultaneously identify the individual efficiency for barometric effect and load of tidal sea considering their combined observation of groundwater level in aquifer system. An innovative application has been demonstrated for the deep aquifers adjacent to the West Pacific Ocean.

Coastal inundation risk assessment due to subsidence and sea level rise in a Mediterranean alluvial plain (Volturno coastal plain - southern Italy)

NASA Astrophysics Data System (ADS)

Ciro Aucelli, Pietro Patrizio; Di Paola, Gianluigi; Incontri, Pietro; Rizzo, Angela; Vilardo, Giuseppe; Benassai, Guido; Buonocore, Berardino; Pappone, Gerardo

2017-11-01

Interdisciplinary studies of the last years highlight that the Italian coasts are significantly subject to retreat and to inundation by sea ingression due to natural and anthropic causes. In this study, the effects of future relative sea level have been evaluated for the Volturno River Plain, one of the widest coastal plain in southern Italy. The plain is characterized by high economical and ecological value, for the presence of farm activities, tourist structures and wetland protected zones. The study area is potentially prone to coastal flooding due to its very low topography and because it is affected by a severe subsidence, which emphasize the local effect of sea level rise due to the ongoing climate changes. In accordance with the guidelines of the MEDFLOOD project, the areas prone to inundation in the years 2065 and 2100 have been evaluated by comparing the future topographical information and expected relative sea level scenarios. The local Vertical Ground Displacements have been derived by PS-InSAR processing data whilst the mean values of the scenarios RCP 2.6 and RCP 8.5 provided by the IPCC (2014) have been used as future sea level projections in 2065 and 2100. The PS-InSar data elaboration shows that the area affected by subsidence corresponds to 35% of the Volturno plain and that the annual rate of the phenomenon ranges between -1 and -25 mm/yr. The inundation analysis, based on the classification of the areas in four hazard classes, indicates that in 2065 the zones located below the sea level will increase approximately of 50% respect to the present conditions, while between 2065 and 2100 the increase can be at least of 60% (IPCC, RCP 8.5 scenarios). Considering the socio-economical and ecological exposure, evaluated following the EUROSION project guidelines, the coastal flooding risk maps have been produced. Almost 8.2 km2 and 14.4 km2 of the investigated area has to be considered subject to very high marine inundation risk in 2065 and 2100, respectively.

The SAVEMEDCOASTS Project

NASA Astrophysics Data System (ADS)

Anzidei, Marco; Patias, Petros; Forlenza, Giovanna; Trivigno, Maria Lucia; Michetti, Melania; Torresan, Silvia; Loizidou, Xenia; Petousis, Thanos; Doumaz, Fawzi; Lorito, Stefano; Brunori, Carlo Alberto; Pesci, Arianna; Carmisciano, Cosmo

2017-04-01

The SAVEMEDCOASTS Project (Sea Level Rise Scenarios along the Mediterranean Coasts), focuses on the Prevention Priority program of the European Commission ECHO A.5 "Civil protection policy, Prevention, Preparedness and Disaster Risk Reduction" and aims to respond to the need for people and assets prevention from natural disasters in Mediterranean coastal areas undergoing to increasing sea level rise and climate change impacts. The goals of the project are: i) to support civil protection at different levels and with different tools and methods to produce exhaustive risk assessments for different periods; ii) to improve governance and raise community awareness towards the impacts of sea level rise and related hazard; iii) to foster the cooperation amongst science, affected communities and civil protection organizations within and between targeted Mediterranean areas. Advanced methods are implied to develop multi-hazard assessments and existing databases for low-lying coastal areas already below or at less than 1 m above sea level, characterized by high economic and environmental value. The effects of sea level rise are assessed by mapping the multi-temporal scenarios of the inland extension of marine flooding and coastline position up to 2100, also temporarily increased during storms or tsunamis. They will result from i) the best available high resolution Digital Terrain Models (DTM); ii) known rates of land subsidence and iii) local sea level rise estimates. Finally, information is transferred to society, policy makers and stakeholders through an open web platform populated with collected information, videos and photo galleries, project results and guidelines. Here we show the strategy and goals of the SAVEMEDCOASTS Project.

Application of precise altimetry to the study of precise leveling of the sea surface, the Earth's gravity field, and the rotation of the Earth

NASA Technical Reports Server (NTRS)

Segawa, J.; Ganeko, Y.; Sasaki, M.; Mori, T.; Ooe, M.; Nakagawa, I.; Ishii, H.; Hagiwara, Y.

1991-01-01

Our program includes five research items: (1) determination of a precision geoid and gravity anomaly field; (2) precise leveling and detection of tidal changes of the sea surface and study of the role of the tide in the global energy exchange; (3) oceanic effect on the Earth's rotation and polar motion; (4) geological and geophysical interpretation of the altimetry gravity field; and (5) evaluation of the effectiveness of local tracking of TOPEX/POSEIDON by use of a laser tracker.

Late Holocene sea- and land-level change on the U.S. southeastern Atlantic Coast

USGS Publications Warehouse

Kemp, Andrew C.; Bernhardt, Christopher E.; Horton, Benjamin P.; Kopp, Robert E.; Vane, Christopher H.; Peltier, W. Richard; Hawkes, Andrea D.; Donnelly, Jeffrey P.; Parnell, Andrew C.; Cahill, Niamh

2015-01-01

Late Holocene relative sea-level (RSL) reconstructions can be used to estimate rates of land-level (subsidence or uplift) change and therefore to modify global sea-level projections for regional conditions. These reconstructions also provide the long-term benchmark against which modern trends are compared and an opportunity to understand the response of sea level to past climate variability. To address a spatial absence of late Holocene data in Florida and Georgia, we reconstructed ~ 1.3 m of RSL rise in northeastern Florida (USA) during the past ~ 2600 years using plant remains and foraminifera in a dated core of high salt-marsh sediment. The reconstruction was fused with tide-gauge data from nearby Fernandina Beach, which measured 1.91 ± 0.26 mm/year of RSL rise since 1900 CE. The average rate of RSL rise prior to 1800 CE was 0.41 ± 0.08 mm/year. Assuming negligible change in global mean sea level from meltwater input/removal and thermal expansion/contraction, this sea-level history approximates net land-level (subsidence and geoid) change, principally from glacio-isostatic adjustment. Historic rates of rise commenced at 1850–1890 CE and it is virtually certain (P = 0.99) that the average rate of 20th century RSL rise in northeastern Florida was faster than during any of the preceding 26 centuries. The linearity of RSL rise in Florida is in contrast to the variability reconstructed at sites further north on the U.S. Atlantic coast and may suggest a role for ocean dynamic effects in explaining these more variable RSL reconstructions. Comparison of the difference between reconstructed rates of late Holocene RSL rise and historic trends measured by tide gauges indicates that 20th century sea-level trends along the U.S. Atlantic coast were not dominated by the characteristic spatial fingerprint of melting of the Greenland Ice Sheet.

Assessing hydrological effects of human interventions on coastal systems: numerical applications to the Venice Lagoon

NASA Astrophysics Data System (ADS)

Ferrarin, C.; Ghezzo, M.; Umgiesser, G.; Tagliapietra, D.; Camatti, E.; Zaggia, L.; Sarretta, A.

2012-12-01

The hydrological consequences of historical, contemporary and future human activities on a coastal system were investigated by means of numerical models. The changes in the morphology of the Lagoon of Venice during the last century result from the sedimentological response to the combined effects of human interventions on the environment and global changes. This study focuses on changes from 1927 to 2012 and includes the changes planned for the protection of the city of Venice from storm surges and exceptional tides under future sea level rise scenarios. The application of a hydrodynamic model to simulate the circulation of water masses and the transport of a passive tracer enabled the analysis of the morphodynamic effects on the lagoon circulation and the interaction with the sea. The absolute values of the exchange between the lagoon and sea increased from 1927 to 2002 (from 3900 to 4600 m3 s-1), while the daily fraction of lagoon water volume exchanged decreased. At the same time, the water renewal time shortened from 11.9 to 10.8 days. Morphological changes during the last decade induced an increase of the basin-wide water renewal time (from 10.8 to 11.3 days). In the future, Venice Lagoon will evolve to a more restricted environment due to sea level rise and periodical closure of the lagoon from the sea during flooding events. Simulated scenarios of sea level rise showed that under fall-winter conditions the water renewal time will increased considerably especially in the central part of the lagoon. Furthermore, some considerations on the impact of the hydromorphological changes on the ecological dynamics are proposed.

Multi-linear regression of sea level in the south west Pacific as a first step towards local sea level projections

NASA Astrophysics Data System (ADS)

Kumar, Vandhna; Meyssignac, Benoit; Melet, Angélique; Ganachaud, Alexandre

2017-04-01

Rising sea levels are a critical concern in small island nations. The problem is especially serious in the western south Pacific, where the total sea level rise over the last 60 years is up to 3 times the global average. In this study, we attempt to reconstruct sea levels at selected sites in the region (Suva, Lautoka, Noumea - Fiji and New Caledonia) as a mutiple-linear regression of atmospheric and oceanic variables. We focus on interannual-to-decadal scale variability, and lower (including the global mean sea level rise) over the 1979-2014 period. Sea levels are taken from tide gauge records and the ORAS4 reanalysis dataset, and are expressed as a sum of steric and mass changes as a preliminary step. The key development in our methodology is using leading wind stress curl as a proxy for the thermosteric component. This is based on the knowledge that wind stress curl anomalies can modulate the thermocline depth and resultant sea levels via Rossby wave propagation. The analysis is primarily based on correlation between local sea level and selected predictors, the dominant one being wind stress curl. In the first step, proxy boxes for wind stress curl are determined via regions of highest correlation. The proportion of sea level explained via linear regression is then removed, leaving a residual. This residual is then correlated with other locally acting potential predictors: halosteric sea level, the zonal and meridional wind stress components, and sea surface temperature. The statistically significant predictors are used in a multi-linear regression function to simulate the observed sea level. The method is able to reproduce between 40 to 80% of the variance in observed sea level. Based on the skill of the model, it has high potential in sea level projection and downscaling studies.

Parasites in the Wadden Sea food web

NASA Astrophysics Data System (ADS)

Thieltges, David W.; Engelsma, Marc Y.; Wendling, Carolin C.; Wegner, K. Mathias

2013-09-01

While the free-living fauna of the Wadden Sea has received much interest, little is known on the distribution and effects of parasites in the Wadden Sea food web. However, recent studies on this special type of trophic interaction indicate a high diversity of parasites in the Wadden Sea and suggest a multitude of effects on the hosts. This also includes effects on specific predator-prey relationships and the general structure of the food web. Focussing on molluscs, a major group in the Wadden Sea in terms of biomass and abundance and an important link between primary producers and predators, we review existing studies and exemplify the ecological role of parasites in the Wadden Sea food web. First, we give a brief inventory of parasites occurring in the Wadden Sea, ranging from microparasites (e.g. protozoa, bacteria) to macroparasites (e.g. helminths, parasitic copepods) and discuss the effects of spatial scale on heterogeneities in infection levels. We then demonstrate how parasites can affect host population dynamics by acting as a strong mortality factor, causing mollusc mass mortalities. In addition, we will exemplify how parasites can mediate the interaction strength of predator-prey relationships and affect the topological structure of the Wadden Sea food web as a whole. Finally, we highlight some ongoing changes regarding parasitism in the Wadden Sea in the course of global change (e.g. species introduction, climate change) and identify important future research questions to entangle the role of parasites in the Wadden Sea food web.

Water levels in major artesian aquifers of the New Jersey Coastal Plain, 1983

USGS Publications Warehouse

Eckel, J.A.; Walker, R.L.

1986-01-01

Water levels and changes in water levels in the major aquifers of the New Jersey Coastal Plain are documented. Water levels in 1,071 wells were measured in 1983, and are compared with 827 water level measurements made in the same wells in 1978. Increased groundwater withdrawals from the major artesian aquifers that underlie the New Jersey Coastal Plain have caused large cones of depression in the artesian heads. These cones are delineated on detailed potentiometric surface maps based on water level data collected in the fall of 1983. Hydrographs from observation wells show trends of water levels for the 6-year period of 1978 through 1983. The Potomac-Raritan-Magothy aquifer system is divided into the lower, middle, and upper aquifers. The potentiometric surfaces in these aquifers form large cones of depression centered in the Camden and Middlesex-Monmouth County areas. Measured water levels declined as much as 23 ft in these areas for the period of study. The lowest levels are 96 ft below sea level in Camden County and 91 ft below sea level in the Middlesex-Monmouth County area. Deep cones of depression in coastal Monmouth and Ocean counties in both the Englishtown aquifer system and Wenonah-Mount Laurel aquifer are similar in location and shape. This is because of an effective hydraulic connection between these aquifers. Measured water levels declined as much as 29 ft in the Englishtown aquifer system and 21 ft in the Wenonah-Mount Laurel aquifer during the period of study. The lowest levels are 249 ft below sea level in the Englishtown aquifer system and 196 ft below sea level in the Wenonah-Mount Laurel aquifer. Water levels in the Piney Point aquifer are as low as 75 ft below sea level at Seaside Park, Ocean County and 35 ft below sea level in southern Cumberland County. Water levels in Cumberland County are affected by large withdrawals of groundwater in Kent County, Delaware. Water levels in the Atlantic City 800 ft sand of the Kirkwood Formation define an extensive elongated cone of depression. Water levels are as low as 76 ft below sea level near Margate and Ventnor, Atlantic County. Measured water levels declined as much as 9 ft in the coastal region between Cape May County and Ocean County for the period of study. (Author 's abstract)

The Adriatic Sea: A Long-Standing Laboratory for Sea Level Studies

NASA Astrophysics Data System (ADS)

Vilibić, Ivica; Šepić, Jadranka; Pasarić, Mira; Orlić, Mirko

2017-10-01

The paper provides a comprehensive review of all aspects of Adriatic Sea level research covered by the literature. It discusses changes occurring over millennial timescales and documented by a variety of natural and man-made proxies and post-glacial rebound models; mean sea level changes occurring over centennial to annual timescales and measured by modern instruments; and daily and higher-frequency changes (with periods ranging from minutes to a day) that are contributing to sea level extremes and are relevant for present-day flooding of coastal areas. Special tribute is paid to the historic sea level studies that shaped modern sea level research in the Adriatic, followed by a discussion of existing in situ and remote sensing observing systems operating in the Adriatic area, operational forecasting systems for Adriatic storm surges, as well as warning systems for tsunamis and meteotsunamis. Projections and predictions of sea level and related hazards are also included in the review. Based on this review, open issues and research gaps in the Adriatic Sea level studies are identified, as well as the additional research efforts needed to fill the gaps. The Adriatic Sea, thus, remains a laboratory for coastal sea level studies for semi-enclosed, coastal and marginal seas in the world ocean.

The impact of half-a-degree Celsius upon the spatial pattern of future sea-level change.

NASA Astrophysics Data System (ADS)

Jackson, Luke

2017-04-01

It has been shown that the global thermal expansion of sea level and ocean dynamics are linearly related to global temperature change. On this basis one can estimate the difference in local sea-level change between a 1.5°C and 2.0°C world. The mitigation scenario RCP 2.6 shows an end-of-century global temperature range of 0.9 to 2.3°C (median 1.6°C). Additional sea-level components, such as mass changes in ice sheets, glaciers and land-water storage have unique spatial patterns that contribute to sea-level change and will be indirectly affected by global temperature change. We project local sea-level change for RCP 2.6 using sub-sets of models in the CMIP5 archive that follow different global temperature pathways. The method used to calculate local sea-level change is probabilistic and combines the normalised spatial patterns of sea-level components with global average projections of individual sea-level components.

The Orinoco megadelta as a conservation target in the face of the ongoing and future sea level rise.

PubMed

Vegas-Vilarrúbia, T; Hernández, E; Rull, Valentí; Rull Vegas, Elisa

2015-05-15

Currently, risk assessments related to rising sea levels and the adoption of defensive or adaptive measures to counter these sea level increases are underway for densely populated deltas where economic losses might be important, especially in the developed world. However, many underpopulated deltas harbouring high biological and cultural diversity are also at risk but will most likely continue to be ignored as conservation targets. In this study, we explore the potential effects of erosion, inundation and salinisation on one of the world's comparatively underpopulated megadeltas, the Orinoco Delta. With a 1 m sea level rise expected to occur by 2100, several models predict a moderate erosion of the delta's shorelines, migration or loss of mangroves, general inundation of the delta with an accompanying submersion of wetlands, and an increase in the distance to which sea water intrudes into streams, resulting in harm to the freshwater biota and resources. The Warao people are the indigenous inhabitants of the Orinoco Delta and currently are subject to various socioeconomic stressors. Changes due to sea level rise will occur extremely rapidly and cause abrupt shifts in the Warao's traditional environments and resources, resulting in migrations and abandonment of their ancestral territories. However, evidence indicates that deltaic aggradation/accretion processes at the Orinoco delta due to allochthonous sediment input and vegetation growth could be elevating the surface of the land, keeping pace with the local sea level rise. Other underpopulated and large deltas of the world also may risk immeasurable biodiversity and cultural losses and should not be forgotten as important conservation targets. Copyright © 2015. Published by Elsevier B.V.

Gravity Field Changes due to Long-Term Sea Level Changes

NASA Astrophysics Data System (ADS)

Makarynskyy, O.; Kuhn, M.; Featherstone, W. E.

2004-12-01

Long-term sea level changes caused by climatic changes (e.g. global warming) will alter the system Earth. This includes the redistribution of ocean water masses due to the migration of cold fresh water from formerly ice-covered regions to the open oceans mainly caused by the deglaciation of polar ice caps. Consequently also a change in global ocean circulation patterns will occur. Over a longer timescale, such mass redistributions will be followed by isostatic rebound/depression due to the changed surface un/loading, resulting in variable sea level change around the world. These, in turn, will affect the gravity field, location of the geocentre, and the Earth's rotation vector. This presentation focuses mainly on gravity field changes induced by long-term (hundredths to many thousand years) sea level changes using an Earth System Climate Model (ESCM) of intermediate complexity. In this study, the coupled University of Victoria (Victoria, Canada) Earth System Climate Model (Uvic ESCM) was used, which embraces the primary thermodynamic and hydrological components of the climate system including sea and land-ice information. The model was implemented to estimate changes in global precipitation, ocean mass redistribution, seawater temperature and salinity on timescales from hundreds to thousands years under different greenhouse warming scenarios. The sea level change output of the model has been converted into real mass changes by removing the steric effect, computed from seawater temperature and salinity information at different layers also provided by Uvic ESCM. Finally the obtained mass changes have been converted into changes of the gravitational potential and subsequently of the geoid height using a spherical harmonic representation of the different data. Preliminary numerical results are provided for sea level change as well as change in geoid height.

A near uniform basin-wide sea level fluctuation over the Japan/East Sea: A semienclosed sea with multiple straits

NASA Astrophysics Data System (ADS)

Kim, Seung-Bum; Fukumori, Ichiro

2008-06-01

Sea level of the Japan/East Sea observed by the TOPEX/Poseidon (T/P) satellite altimeter is analyzed using a 1/4°-resolution ocean general circulation model. A significant fraction of the Japan/East Sea sea level variability is found to be spatially uniform with periods ranging from 20 d to a year. The model simulation is consistent with T/P records in terms of the basin-wide sea level fluctuation's spectral energy and coherence. The simulation indicates that the changes are barotropic in nature and controlled, notably at high frequencies, by the net mass transport through the straits of the Japan/East Sea driven by winds in the vicinity of the Korea/Tsushima and Soya Straits. A series of barotropic simulations suggest that the sea level fluctuations are the result of a dynamic balance at the straits among near-strait winds, friction, and geostrophic control. The basin-wide sea level response is a linear superposition of changes due to winds near the individual straits. In particular, a basin-wide sea level response can be established by winds near either one of the straits alone. For the specific geometry and winds, winds near the Soya Strait have a larger impact on the Japan/East Sea mean sea level than those near the Korea/Tsushima Strait.

Monitoring and Management of Coastal Zones Which are Under Flooding Risk with Remote Sensing and GIS

NASA Astrophysics Data System (ADS)

Direk, S.; Seker, D. Z.; Musaoglu, N.; Gazioglu, C.

2012-12-01

Coastal zone areas play an important role in value to the welfare of nations and provides natural, social, cultural and economic benefits and increased quality of life. A great majority of the earth population live in coastal zone areas and they are under flooding risk due to tsunamies, storm surge, typhoon, sea level rise, precipitation and dam destruction. Global warming from the grenhouse effect raises sea level by expanding seawater, melting water and causing ice sheets to melt. Based on a selection of nine long, high quality tide gauge records, Holgate analyzed that the Mean Sea Level (MSL) rise over the period of 1904-2003 was found to be 1.74 ± 0.16 mm/year. Consider the whole century showed that the high decadal rates of change in global MSL was observed during the last 20 years of the records. Based on 4 tide gauge records in Marmara Sea, Aegean Sea and Eastern Mediterranean, Yildiz analyzed that MSL rise during 1984-2002 was found to be 9.6 ± 0.9 mm/year, 5.1 ± 1 mm/year and 8.7 ± 0.8 mm/year respectively. By analyzing the whole recorded data, it is found that the annual MSL rise in eastern mediterranean was 4-7 mm/year which was higher than the global prediction. A rise in sea level would accelerate coastal erosion, aggravate flooding, threaten coastal area structures and inundate wetlands. The salinity of rivers and bays would increase. A 1 meter in sea level rise would enable a 15-20 year storm to flood many areas. Higher water levels would reduce coastal drainage which would cause an increase flooding by rain storms. Finally, a rise in sea level would raise water tables and would flood basements. Geographic Information System (GIS) is a state of art technology and operationally being used more frequently by commercial and scientific society. GIS system provides a stable platform for the integration of data from different sources, allows a large quantity of data to be stored and processed, provides a seamless geographical database and provides a great flexibility for the display and visualization of data to a wider audience. Today GIS, plays a key role in monitoring and management procedures and re-shaping the environment. The capability of GIS in handling spatial data, presented new opportunities for adaptation of more cost-effective and efficient procedures. By using remote sensing and GIS, coastal zone could be monitored and managed more easily. The map/chart of interested coastal areas could be done more accurately and rapidly. Maps/charts of areas before and after flooding could be done by using satellites or areal images and the effect of damage could be analyzed in a short time.

Effects of climate change on wave height at the coast

NASA Astrophysics Data System (ADS)

Wolf, J.

2003-04-01

To make progress towards the ultimate objective of predicting coastal vulnerability to climate change, we need to predict the probability of extreme values of sea level and wave height, and their likely variation with changing climate. There is evidence of changes in sea level and wave height on various time-scales. For example, the North Atlantic Oscillation appears to be responsible for increasing wave height in the North Atlantic over recent decades. The impact of changes in wave height in the North Atlantic at the coastline in the North Sea, the Hebrides/Malin Shelf and the English Channel will be quite different. Three different, and contrasting areas are examined The effect of changing sea levels, due to global warming and changes in tides and surge height and frequency, is combined with increases in offshore wave height. Coastal wave modelling, using the WAM and SWAN wave models, provides a useful tool for examining the possible impacts of climate change at the coast. This study is part of a Tyndall Centre project which is examining the vulnerability of the UK coast to changing wave climate and sea level. These changes are likely to be especially important in low-lying areas with coastal wetlands such as the north Norfolk coast, which has been selected as a detailed case study area. In this area there are offshore shallow banks and extensive inter-tidal areas. There are transitions from upper marsh to freshwater grazing marshes, sand dunes, shingle beaches, mudflats and sandflats. Many internationally important and varied habitats are threatened by rising sea levels and changes in storminess due to potential climate change effects. Likely changes in overtopping of coastal embankments, inundation of intertidal areas, sediment transport and coastal erosion are examined. Changes in low water level may be important as well as high water. The second area of study is Christchurch Bay in the English Channel. The English Channel is exposed to swell from the North Atlantic and a moderate tidal range. The coastline is quite developed with popular beaches. There are defended and undefended stretches of coastline. The waves reaching the coastline are modulated by the strong tidal streams in the Solent and shoal areas like Shingles Bank. The Sea of the Hebrides is an area important for fishing and tourism, but is the part of the UK exposed to the most severe waves, being most directly connected with the North Atlantic. The UK’s first wave power plant is in operation on Islay. Sea level changes are likely to be relatively unimportant but changes in wave climate could have a direct impact on local economic activity.

Statistical analysis of the extreme values of dynamic sea level by spatial interpolation for a beach of the Mediterranean French coast

NASA Astrophysics Data System (ADS)

Kergadallan, X.; Metzler, N., Sr.

2016-12-01

The knowledge of sea levels along the coastline is of the utmost importance for characterization of flood risks in coastal areas, with a particular interest devoted to extreme values because they may induce the most dramatic consequences.The Cerema is a new French public body in support of national and local authorities in the field of sustainable development. At the request of French authorities, the Cerema has studied with a statistical approach the extreme values of the dynamic sea levels for one beach of the Mediterranean coast in Southern France.The beach is located at Saint-Aygulf, between Toulon and Nice. This site is critical because it's a tourist place with some buildings closed to the sea.The dynamic sea level studied includes a predictive part, the tidal level with about 40 cm of tidal range, and a non predictive part due to meteorological effect (difference of atmospheric pressures, wind effect) and breaking wave (wave run-up).There is no data of sea level measurement or numerical simulation at Saint-Aygulf. The development of a model to compute numerical simulations is out of the scope of this study.The closest tide gauges are located at more 50 km from Saint-Aygulf, in Toulon and Nice, with more than 15 years of observations.The originality of this work is to transform data from Toulon and Nice, so that the estimations of the dynamic sea level with these transformed data are representative of Saint-Aygulf. The final result is a weighted mean of both estimations (weight inversely proportional of the distance).The wave run-up is computed with the Stockdon et al. [2006] formula. Wave data come from ANEMOC2 data base (hindcast simulations from Cerema and EDF R&D). The dependence between offshore sea-states and tide gauge measurement is modelled by a Gumbel copula. Data transformation of Toulon and Nice takes into account the specific conditions of wave climate at Saint-Aygulf (exposure and energy loss during the propagation).As specified by the theory, the dependence model (Gumbel copula) is defined if and only if values of wave and still water level (tide-gauge record) are simultaneously extreme. It's why we introduce a low and a high limit in order to border the final result.At the end we discuss about the limits of the method and we give some ideas to improve it.

Teaching of the subject "density difference caused by salinity", one of the reasons that plays role in the occurrence of currents in straits, seas and oceans by the use of a teaching material

NASA Astrophysics Data System (ADS)

Gumussoy, Verim

2015-04-01

Large masses of moving water in seas and oceans are called currents. Root causes of currents are steady winds that occur due to the global atmospheric system and the density differences caused by different heat and salinity levels of water masses. Different feeding and evaporation characteristics of seas and oceans result in salinity and density levels. As a result, subsurface currents occur in straits where seas with different salinity and density levels meet and in the nearby seas. The Bosporus in Istanbul where I live and the school I am working at is has these subsurface currents. In the Black Sea where the rivers the Danube, Dnieper, Don, Yesilirmak, Kizilirmak and Sakarya flow into and the evaporation level is less due to the latitude effect, salinity level is less compared to Marmara and Aegean Seas. As Marmara Sea has higher salt amount than Black Sea, there is a great density difference between these two seas. Marmara Sea has a higher concentration of salt and therefore a higher density than Black Sea. And this leads to occurrence of subsurface currents in the Bosporus. I get my students to carry out a small demonstration to help them understand the occurrence of ocean currents and currents in the seas and the Bosporus by the use of a material. We need very simple materials to carry out this demonstration. These are an aquarium, a bowl, water, salt, dye and a mixer. The demonstration is carried out as follows: we put water, salt and dye in the bowl and mix it well. The salt will increase the density of the water and the dye will help distinguish the salty water. Then we put tap water half way to the aquarium and pour the mixture in the bowl to the aquarium slowly. As a result, the colored salty water sinks down due to its higher density, setting an example of a subsurface current. Natural events occur in very long periods by great dynamic systems, making understanding of them difficult. It is important to use different kinds of materials that address to different senses in geography lessons to promote effective and fun learning. Thus, geography lessons should be based on teaching principles such as 'from concrete to abstract' and 'from near-to-far' principles. Also, teaching methods such as visualization, simulation and experiment should be applied during the lessons. The use of this material will help students comprehend how subsurface currents in the straits, seas and oceans occur. By this simple experiment, students will be able to see what kind of a movement takes place under the Bosporus on which they travel by ferry and they will have the opportunity to carry it out themselves, making the lesson more fun.

Cenozoic stratigraphy of the Sahara, Northern Africa

USGS Publications Warehouse

Swezey, Christopher S.

2009-01-01

This paper presents an overview of the Cenozoic stratigraphic record in the Sahara, and shows that the strata display some remarkably similar characteristics across much of the region. In fact, some lithologies of certain ages are exceptionally widespread and persistent, and many of the changes from one lithology to another appear to have been relatively synchronous across the Sahara. The general stratigraphic succession is that of a transition from early Cenozoic carbonate strata to late Cenozoic siliciclastic strata. This transition in lithology coincides with a long-term eustatic fall in sea level since the middle Cretaceous and with a global climate transition from a Late Cretaceous–Early Eocene “warm mode” to a Late Eocene–Quaternary “cool mode”. Much of the shorter-term stratigraphic variability in the Sahara (and even the regional unconformities) also can be correlated with specific changes in sea level, climate, and tectonic activity during the Cenozoic. Specifically, Paleocene and Eocene carbonate strata and phosphate are suggestive of a warm and humid climate, whereas latest Eocene evaporitic strata (and an end-Eocene regional unconformity) are correlated with a eustatic fall in sea level, the build-up of ice in Antarctica, and the appearance of relatively arid climates in the Sahara. The absence of Oligocene strata throughout much of the Sahara is attributed to the effects of generally low eustatic sea level during the Oligocene and tectonic uplift in certain areas during the Late Eocene and Oligocene. Miocene sandstone and conglomerate are attributed to the effects of continued tectonic uplift around the Sahara, generally low eustatic sea level, and enough rainfall to support the development of extensive fluvial systems. Middle–Upper Miocene carbonate strata accumulated in northern Libya in response to a eustatic rise in sea level, whereas Upper Miocene mudstone accumulated along the south side of the Atlas Mountains because uplift of the mountains blocked fluvial access to the Mediterranean Sea. Uppermost Miocene evaporites (and an end-Miocene regional unconformity) in the northern Sahara are correlated with the Messinian desiccation of the Mediterranean Sea. Abundant and widespread Pliocene paleosols are attributed to the onset of relatively arid climate conditions and (or) greater variability of climate conditions, and the appearance of persistent and widespread eolian sediments in the Sahara is coincident with the major glaciation in the northern hemisphere during the Pliocene.

Sea Level Trend and Variability in the Straits of Singapore and Malacca

NASA Astrophysics Data System (ADS)

Luu, Q.; Tkalich, P.

2013-12-01

The Straits of Singapore and Malacca (SSM) connect the Andaman Sea located northeast of the Indian Ocean to the South China Sea, the largest marginal sea situated in the tropical Pacific Ocean. Consequently, sea level in the SSM is assumed to be governed by various regional phenomena associated with the adjacent parts of Indian and Pacific Oceans. At annual scale sea level variability is dominant by the Asian monsoon. Interannual sea level signals are modulated by the El Niño-Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD). In the long term, regional sea level is driven by the global climate change. However, relative impacts of these multi-scale phenomena on regional sea level in the SSM are yet to be quantified. In present study, publicly available tide gauge records and satellite altimetry data are used to derive long-term sea level trend and variability in SSM. We used the data from research-quality stations, including four located in the Singapore Strait (Tanjong Pagar, Raffles Lighthouse, Sultan Shoal and Sembawang) and seven situated in the Malacca Strait (Kelang, Keling, Kukup, Langkawji, Lumut, Penang and Ko Taphao Noi), each one having 25-39 year data up to the year 2011. Harmonic analysis is performed to filter out astronomic tides from the tide gauge records when necessary; and missing data are reconstructed using identified relationships between sea level and the governing phenomena. The obtained sea level anomalies (SLAs) and reconstructed mean sea level are then validated against satellite altimetry data from AVISO. At multi-decadal scale, annual measured sea level in the SSM is varying with global mean sea level, rising for the period 1984-2009 at the rate 1.8-2.3 mm/year in the Singapore Strait and 1.1-2.8 mm/year in the Malacca Strait. Interannual regional sea level drops are associated with El Niño events, while the rises are correlated with La Niña episodes; both variations are in the range of ×5 cm with correlation coefficient of -0.7 (in correspondence with the Multivariate ENSO Index). The IOD modulates interannual sea level variability only in the Malacca Strait in the range of ×3 cm with a correlation coefficient of -0.6 (with respect to the Dipole Mode Index). At annual scale, SLAs in the SSM are mainly monsoon-driven; of the order of 20 cm. Mean sea level in the Singapore Strait reach the peak during northeast monsoon and trough during southwest monsoon; while these in the Malacca Strait are highest at middle of both monsoons and lowest during their transitional monsoonal seasons. Global and regional signals are quantitatively captured in the SSM. In comparison with the global sea level trends, SSM sea level rise are larger for recent decades 1984-2009. Taking into account the rough estimate of land subsidence rates in Singapore (2006-2011) and Peninsular Malaysia (1994-2004), the trend of absolute sea level rise in SSM follows regional tendency. At interannual scale, ENSO modulates sea level variabilities in the entire SSM region, while IOD affects the Malacca Strait only. At annual scale, sea level responds differently to the Asian monsoon: quasi-periodic cycles are observed twice a year in the Malacca Strait, but once a year in the Singapore Strait. Such behavior implies that the narrow channel constriction between the Singapore and Malacca Straits may be a reason of different variability of sea level in the domains.

Sea-level evaluation of digitally implemented turbojet engine control functions

NASA Technical Reports Server (NTRS)

Arpasi, D. J.; Cwynar, D. S.; Wallhagen, R. E.

1972-01-01

The standard hydromechanical control system of a turbojet engine was replaced with a digital control system that implemented the same control laws. A detailed discussion of the digital control system in use with the engine is presented. The engine was operated in a sea-level test stand. The effects of control update interval are defined, and a method for extending this interval by using digital compensation is discussed.

Clusters of community exposure to coastal flooding hazards based on storm and sea level rise scenarios—implications for adaptation networks in the San Francisco Bay region

USGS Publications Warehouse

Hummel, Michelle; Wood, Nathan J.; Schweikert, Amy; Stacey, Mark T.; Jones, Jeanne; Barnard, Patrick L.; Erikson, Li H.

2018-01-01

Sea level is projected to rise over the coming decades, further increasing the extent of flooding hazards in coastal communities. Efforts to address potential impacts from climate-driven coastal hazards have called for collaboration among communities to strengthen the application of best practices. However, communities currently lack practical tools for identifying potential partner communities based on similar hazard exposure characteristics. This study uses statistical cluster analysis to identify similarities in community exposure to flooding hazards for a suite of sea level rise and storm scenarios. We demonstrate this approach using 63 jurisdictions in the San Francisco Bay region of California (USA) and compare 21 distinct exposure variables related to residents, employees, and structures for six hazard scenario combinations of sea level rise and storms. Results indicate that cluster analysis can provide an effective mechanism for identifying community groupings. Cluster compositions changed based on the selected societal variables and sea level rise scenarios, suggesting that a community could participate in multiple networks to target specific issues or policy interventions. The proposed clustering approach can serve as a data-driven foundation to help communities identify other communities with similar adaptation challenges and to enhance regional efforts that aim to facilitate adaptation planning and investment prioritization.

Dietary supplementation of biofloc influences growth performance, physiological stress, antioxidant status and immune response of juvenile sea cucumber Apostichopus japonicus (Selenka).

PubMed

Chen, Jinghua; Ren, Yichao; Wang, Guodong; Xia, Bin; Li, Yuquan

2018-01-01

Bioflocs are rich in various probiotics and bioactive compounds, which play an important role in improving growth and health status of aquatic organisms. A 60-day experiment was conducted to investigate the effects of dietary supplementation of biofloc on growth performance, digestive enzyme activity, physiological stress, antioxidant status, expression of immune-related genes and disease resistance of sea cucumber Apostichopus japonicus. Juvenile sea cucumbers were fed five experimental diets containing graded levels of biofloc from 0% to 20% (referred as B0, B5, B10, B15 and B20, respectively). The results showed that the sea cucumbers at dietary supplementation levels of 10%-15% biofloc had significantly higher specific growth rate (SGR) compared to control group (diet B0). Digestive enzyme activity increased with the increasing of dietary biofloc level, while no significant difference was found between diets B15 and B20. Dietary supplementation of biofloc also had significant influences on physiological stress parameters except for lactate. There was no significant discrepancy in total coelomocytes counts (TCC) in coelomic fluid of sea cucumber between the treatments. Phagocytosis and respiratory burst of cellular immune at 15% and 20% biofloc levels were significantly higher than those of control group. Significant increases in superoxide dismutase (SOD), total nitric oxide synthase (T-NOS), lysozyme (LSZ), acid phosphatase (ACP) and alkaline phosphatase (AKP) activities of sea cucumber were found at highest dietary supplementation level of 20% biofloc. The expression patterns of immune-related genes (i.e., Hsp90, Hsp70, p105, Rel, NOS and LSZ) in tissues of sea cucumber were analyzed between the experimental diets, and a general trend of up-regulation was observed at higher biofloc levels. Furthermore, dietary 10%-20% biofloc significantly reduced cumulative mortality of sea cucumber after being challenged with Vibrio splendidus. In conclusion, dietary supplementation of biofloc could improve growth performance of A. japonicus, by increasing digestive enzyme activity, releasing physiological stress, enhancing immune response and disease resistance of sea cucumber. The suitable supplemental level of approximately 15% biofloc was recommended in the present study. Copyright © 2017 Elsevier Ltd. All rights reserved.

Probabilistic risk assessment of the effect of acidified seawater on development stages of sea urchin (Strongylocentrotus droebachiensis).

PubMed

Chen, Wei-Yu; Lin, Hsing-Chieh

2018-05-01

Growing evidence indicates that ocean acidification has a significant impact on calcifying marine organisms. However, there is a lack of exposure risk assessments for aquatic organisms under future environmentally relevant ocean acidification scenarios. The objective of this study was to investigate the probabilistic effects of acidified seawater on the life-stage response dynamics of fertilization, larvae growth, and larvae mortality of the green sea urchin (Strongylocentrotus droebachiensis). We incorporated the regulation of primary body cavity (PBC) pH in response to seawater pH into the assessment by constructing an explicit model to assess effective life-stage response dynamics to seawater or PBC pH levels. The likelihood of exposure to ocean acidification was also evaluated by addressing the uncertainties of the risk characterization. For unsuccessful fertilization, the estimated 50% effect level of seawater acidification (EC50 SW ) was 0.55 ± 0.014 (mean ± SE) pH units. This life stage was more sensitive than growth inhibition and mortality, for which the EC50 values were 1.13 and 1.03 pH units, respectively. The estimated 50% effect levels of PBC pH (EC50 PBC ) were 0.99 ± 0.05 and 0.88 ± 0.006 pH units for growth inhibition and mortality, respectively. We also predicted the probability distributions for seawater and PBC pH levels in 2100. The level of unsuccessful fertilization had 50 and 90% probability risks of 5.07-24.51 (95% CI) and 0-6.95%, respectively. We conclude that this probabilistic risk analysis model is parsimonious enough to quantify the multiple vulnerabilities of the green sea urchin while addressing the systemic effects of ocean acidification. This study found a high potential risk of acidification affecting the fertilization of the green sea urchin, whereas there was no evidence for adverse effects on growth and mortality resulting from exposure to the predicted acidified environment.

The flooding of the San Matías Gulf: The Northern Patagonia sea-level curve

NASA Astrophysics Data System (ADS)

Isla, Federico Ignacio

2013-12-01

Northern Patagonia is characterised by tectonic depressions below present sea level. Some of them are today flooded by the sea; others remain emerged although they are at altitudes of - 50 m (Bajo del Gualicho), - 35 m (Salinas Grandes) and - 7 m (Salina La Piedra). San Matías Gulf also was such an emerged depression below contemporary mean sea level during the Late Pleistocene. It flooded between 11,500 and 11,000 years ago, when the sea level surpassed the sill of the gulf (today 50 m below mean sea level) during postglacial sea-level rise. In those days, shrublands extended on the slopes of the tectonic depression. In-situ pieces of woods dredged from the bottom of the gulf at depths of 70 m gave a conventional age of 11,310 ± 150 years BP. We used the wood, together with dated shells from the continental shelf, and shells and organic matter dated from the San Blas, Negro and Chubut coastal plains to construct a sea-level curve. Sea level rise surpassed the present level somewhat before 6000 years BP, reaching a maximum stand of + 6 m. It has since gently diminished towards present sea level.

Health Impact Assessment practice and potential for integration within Environmental Impact and Strategic Environmental Assessments in Italy.

PubMed

Linzalone, Nunzia; Assennato, Giorgio; Ballarini, Adele; Cadum, Ennio; Cirillo, Mario; Cori, Liliana; De Maio, Francesca; Musmeci, Loredana; Natali, Marinella; Rieti, Sabrina; Soggiu, Maria Eleonora; Bianchi, Fabrizio

2014-12-01

Avoiding or minimizing potential environmental impact is the driving idea behind protecting a population's health via Environmental Impact Assessments (EIAs) and Strategic Environmental Assessments (SEAs). However, both are often carried out without any systematic approach. This paper describes the findings of a review of HIA, EIA andSEA experiences carried out by the authors, who act as institutional competent subjects at the national and regional levels in Italy. The analysis of how health is tackled in EIA and SEA procedures could support the definition of a protocol for the integration of HIA with EIA and SEA. Although EIA and SEA approaches include the aim of protecting health,significant technical and methodological gaps are present when assessing health systematically, and their basic principles regarding assessment are unsatisfactory for promoting and addressing healthcare concepts stated by the WHO. HIA is still poorly integrated into the decision-making process, screening and monitoring phases are only occasionally implemented, and operational details are not well-defined. The collaborative approach of institutions involved in environment and health is a core element in a systematic advancement toward supporting effective decisions and effective protection ofthe environment and health. At the Italian national level, the definition of guidelines and tools for HIA, also in relation with EIA and SEA, is of great interest.

Implications of sediment redistribution on modeled sea-level changes over millennial timescales

NASA Astrophysics Data System (ADS)

Ferrier, Ken

2016-04-01

Sea level is a critical link in feedbacks among topography, tectonics, and climate. Over millennial timescales, changes in sea level reshape river networks, regulate organic carbon burial, influence sediment deposition, and set moving boundary conditions for landscape evolution. Sea-level changes influence tectonics by regulating rates and patterns of erosion and deposition, which perturb the surface loads that drive geodynamic processes at depth. These interactions are complex because sea-level changes are influenced by the geomorphic processes that they themselves modify, since sediment redistribution deforms the gravitational and crustal elevation fields that define sea level. A recent advance in understanding the coupling between sea level, tectonics, and topography was the incorporation of sediment redistribution into a gravitationally self-consistent sea-level model, which permits the computation of sea-level responses to erosion and deposition (Dalca et al., 2013, Geophysical Journal International). Here I use this model to quantify changes in sea level resulting from the erosion of some of the most rapidly eroding sites on Earth and the deposition of sediment offshore. These model results show that the sea-level fingerprints of sediment redistribution are strongly variable in space, and that they can represent a significant component of the total sea level change since the last interglacial. This work provides a basis for understanding a fundamental driver of landscape evolution at some of Earth's most geomorphically dynamic sites, and thus aids investigation of the couplings among tectonics, climate, and topography. References Dalca A.V., Ferrier K.L., Mitrovica J.X., Perron J.T., Milne G.A., Creveling J.R., 2013. On postglacial sea level - III. Incorporating sediment redistribution. Geophysical Journal International, doi: 10.1093/gji/ggt089.

Steric sea level change in the Bay of Bengal: investigating the most variable component of sea level change

NASA Astrophysics Data System (ADS)

Uebbing, Bernd; Kusche, Jürgen; Rietbroek, Roelof; Shum, Ck

2015-04-01

Regional sea level change is influenced by contributions from mass sources, like melting of glaciers and the ice-sheets in Greenland and Antarctica, as well as steric contributions from changes in temperature and salinity of the oceans. Radar altimetry indicates a sea level trend in the Bay of Bengal of about 6 mm- yr over the time period of 2002-2014, which is significantly larger than the global mean trend. Here, we explain 80% of this rise by steric contributions and 20% by mass-related contributions. The increased rise of sea level in the Bay of Bengal threatens the coastal vulnerability of the surrounding countries like Bangladesh, where this effect is exacerbated in combination with land subsidence of the very low lying coastal areas. The BanD-AID (Bangladesh Delta: Assessment of the Causes of Sea-level Rise Hazards and Integrated Development of Predictive Modeling Towards Mitigation and Adaptation) project tries to assess the current and future sea level rise and its impacts on the people living in the threatened coastal areas. As a part of this, it is necessary to analyze the different mass and steric contributors to the total sea level rise to aid in the prediction of future risks. We use data from radar altimetry and the GRACE mission to separate the total sea level rise into contributions from mass sources and steric changes. In our approach, temporal GRACE gravity data and Jason-1 and -2 along track altimetry data are fitted to time invariant spatial patterns (fingerprints) to avoid problems with GRACE resolution, filtering, geocenter and related issues. Our results show that in the Bay of Bengal the steric component is influenced by annual and interannual phenomena and, at the same time, it is significantly larger compared to the individual mass contributions, which show a linear and relatively stable behavior over time. We validate the steric component of our inversion by comparing it to independent steric estimates from 4-D gridded temperature and salinity products from different ARGO processing facilities. We also compare to the classical approach of subtracting the mass component, estimated by GRACE, from the total sea level change, measured by altimetry. Furthermore, we assess the sensitivity of our inversion to the normalized steric fingerprints, which are either based on ARGO fields or derived from ocean modeling. While most steric changes are taking place in the upper 700 m of the ocean, our inversion also allows us to (indirectly) assess the influence from the deep ocean, which is not negligible for the total steric trend.

Spatial-temporal analysis of sea level changes in China seas and neighboring oceans by merged altimeter data

NASA Astrophysics Data System (ADS)

Xu, Yao; Zhou, Bin; Yu, Zhifeng; Lei, Hui; Sun, Jiamin; Zhu, Xingrui; Liu, Congjin

2017-01-01

The knowledge of sea level changes is critical important for social, economic and scientific development in coastal areas. Satellite altimeter makes it possible to observe long term and large scale dynamic changes in the ocean, contiguous shelf seas and coastal zone. In this paper, 1993-2015 altimeter data of Topex/Poseidon and its follow-on missions is used to get a time serious of continuous and homogeneous sea level anomaly gridding product. The sea level rising rate is 0.39 cm/yr in China Seas and the neighboring oceans, 0.37 cm/yr in the Bo and Yellow Sea, 0.29 cm/yr in the East China Sea and 0.40 cm/yr in the South China Sea. The mean sea level and its rising rate are spatial-temporal non-homogeneous. The mean sea level shows opposite characteristics in coastal seas versus open oceans. The Bo and Yellow Sea has the most significant seasonal variability. The results are consistent with in situ data observation by the Nation Ocean Agency of China. The coefficient of variability model is introduced to describe the spatial-temporal variability. Results show that the variability in coastal seas is stronger than that in open oceans, especially the seas off the entrance area of the river, indicating that the validation of altimeter data is less reasonable in these seas.

Understanding extreme sea levels for coastal impact and adaptation analysis

NASA Astrophysics Data System (ADS)

Wahl, T.; Haigh, I. D.; Nicholls, R. J.; Arns, A.; Hinkel, J.; Dangendorf, S.; Slangen, A.

2016-12-01

Coastal impact and adaptation assessments require detailed knowledge on extreme sea levels, because increasing damage due to extreme events, such as storm surges and tropical cyclones, is one of the major consequences of sea level rise and climate change. In fact, the IPCC has highlighted in its AR4 report that "societal impacts of sea level change primarily occur via the extreme levels rather than as a direct consequence of mean sea level changes". Over the last few decades, substantial research efforts have been directed towards improved understanding of past and future mean sea level; different scenarios were developed with process-based or semi-empirical models and used for coastal impact assessments at various spatial scales to guide coastal management and adaptation efforts. The uncertainties in future sea level rise are typically accounted for by analyzing the impacts associated with a range of scenarios leading to a vertical displacement of the distribution of extreme sea-levels. And indeed most regional and global studies find little or no evidence for changes in storminess with climate change, although there is still low confidence in the results. However, and much more importantly, there is still a limited understanding of present-day extreme sea-levels which is largely ignored in most impact and adaptation analyses. The two key uncertainties stem from: (1) numerical models that are used to generate long time series of extreme sea-levels. The bias of these models varies spatially and can reach values much larger than the expected sea level rise; but it can be accounted for in most regions making use of in-situ measurements; (2) Statistical models used for determining present-day extreme sea-level exceedance probabilities. There is no universally accepted approach to obtain such values for flood risk assessments and while substantial research has explored inter-model uncertainties for mean sea level, we explore here, for the first time, inter-model uncertainties for extreme sea-levels at large spatial scales and compare them to the uncertainties in mean sea level projections.

Predicting the persistence of coastal wetlands to global change stressors

USGS Publications Warehouse

Guntenspergen, G.; McKee, K.; Cahoon, D.; Grace, J.; Megonigal, P.

2006-01-01

Despite progress toward understanding the response of coastal wetlands to increases in relative sea-level rise and an improved understanding of the effect of elevated CO2 on plant species allocation patterns, we are limited in our ability to predict the response of coastal wetlands to the effects associated with global change. Static simulations of the response of coastal wetlands to sea-level rise using LIDAR and GIS lack the biological and physical feedback mechanisms present in such systems. Evidence from current research suggests that biotic processes are likely to have a major influence on marsh vulnerability to future accelerated rates of sea-level rise and the influence of biotic processes likely varies depending on hydrogeomorphic setting and external stressors. We have initiated a new research approach using a series of controlled mesocosm and field experiments, landscape scale studies, a comparative network of brackish coastal wetland monitoring sites and a suite of predictive models that address critical questions regarding the vulnerability of coastal brackish wetland systems to global change. Specifically, this research project evaluates the interaction of sea level rise and elevated CO2 concentrations with flooding, nutrient enrichment and disturbance effects. The study is organized in a hierarchical structure that links mesocosm, field, landscape and biogeographic levels so as to provide important new information that recognizes that coastal wetland systems respond to multiple interacting drivers and feedback effects controlling wetland surface elevation, habitat stability and ecosystem function. We also present a new statistical modelling technique (Structural Equation Modelling) that synthesizes and integrates our environmental and biotic measures in a predictive framework that forecasts ecosystem change and informs managers to consider adaptive shifts in strategies for the sustainable management of coastal wetlands.

A Poor Relationship Between Sea Level and Deep-Water Sand Delivery

NASA Astrophysics Data System (ADS)

Harris, Ashley D.; Baumgardner, Sarah E.; Sun, Tao; Granjeon, Didier

2018-08-01

The most commonly cited control on delivery of sand to deep water is the rate of relative sea-level fall. The rapid rate of accommodation loss on the shelf causes sedimentation to shift basinward. Field and experimental numerical modeling studies have shown that deep-water sand delivery can occur during any stage of relative sea level position and across a large range of values of rate of relative sea-level change. However, these studies did not investigate the impact of sediment transport efficiency on the relationship between rate of relative sea-level change and deep-water sand delivery rate. We explore this relationship using a deterministic nonlinear diffusion-based numerical stratigraphic forward model. We vary across three orders of magnitude the diffusion coefficient value for marine settings, which controls sediment transport efficiency. We find that the rate of relative sea-level change can explain no more than 1% of the variability in deep-water sand delivery rates, regardless of sediment transport efficiency. Model results show a better correlation with relative sea level, with up to 55% of the variability in deep water sand delivery rates explained. The results presented here are consistent with studies of natural settings which suggest stochastic processes such as avulsion and slope failure, and interactions among such processes, may explain the remaining variance. Relative sea level is a better predictor of deep-water sand delivery than rate of relative sea-level change because it is the sea-level fall itself which promotes sand delivery, not the rate of the fall. We conclude that the poor relationship between sea level and sand delivery is not an artifact of the modeling parameters but is instead due to the inadequacy of relative sea level and the rate of relative sea-level change to fully describe the dimensional space in which depositional systems reside. Subsequently, sea level itself is unable to account for the interaction of multiple processes that contribute to sand delivery to deep water.

Flooded! An Investigation of Sea-Level Rise in a Changing Climate

ERIC Educational Resources Information Center

Gillette, Brandon; Hamilton, Cheri

2011-01-01

Explore how melting ice sheets affect global sea levels. Sea-level rise (SLR) is a rise in the water level of the Earth's oceans. There are two major kinds of ice in the polar regions: sea ice and land ice. Land ice contributes to SLR and sea ice does not. This article explores the characteristics of sea ice and land ice and provides some hands-on…

Grain-size based sea-level reconstruction in the south Bohai Sea during the past 135 kyr

NASA Astrophysics Data System (ADS)

Yi, Liang; Chen, Yanping

2013-04-01

Future anthropogenic sea-level rise and its impact on coastal regions is an important issue facing human civilizations. Due to the short nature of the instrumental record of sea-level change, development of proxies for sea-level change prior to the advent of instrumental records is essential to reconstruct long-term background sea-level changes on local, regional and global scales. Two of the most widely used approaches for past sea-level changes are: (1) exploitation of dated geomorphologic features such as coastal sands (e.g. Mauz and Hassler, 2000), salt marsh (e.g. Madsen et al., 2007), terraces (e.g. Chappell et al., 1996), and other coastal sediments (e.g. Zong et al., 2003); and (2) sea-level transfer functions based on faunal assemblages such as testate amoebae (e.g. Charman et al., 2002), foraminifera (e.g. Chappell and Shackleton, 1986; Horton, 1997), and diatoms (e.g. Horton et al., 2006). While a variety of methods has been developed to reconstruct palaeo-changes in sea level, many regions, including the Bohai Sea, China, still lack detailed relative sea-level curves extending back to the Pleistocene (Yi et al., 2012). For example, coral terraces are absent in the Bohai Sea, and the poor preservation of faunal assemblages makes development of a transfer function for a relative sea-level reconstruction unfeasible. In contrast, frequent alternations between transgression and regression has presumably imprinted sea-level change on the grain size distribution of Bohai Sea sediments, which varies from medium silt to coarse sand during the late Quaternary (IOCAS, 1985). Advantages of grainsize-based relative sea-level transfer function approaches are that they require smaller sample sizes, allowing for replication, faster measurement and higher spatial or temporal resolution at a fraction of the cost of detail micro-palaeontological analysis (Yi et al., 2012). Here, we employ numerical methods to partition sediment grain size using a combined database of marine surface and core samples, and to quantitatively reconstruct sea-level variation since the late Pleistocene in the south Bohai Sea, China. New insights into regional relative sea-level changes since the late Pleistocene are obtained (Yi et al., 2012): (1) The grain size of surface and core samples can be mathematically partitioned using the Weibull distribution into four components. These four components with differing modal sizes and percentages could be interpreted as a long-term suspension component, which only settles under low turbulence conditions, sortable silt and very fine sand components transported by suspension during greater turbulence and bedload transport component, respectively. (2) Through regression and rigorous verification techniques, the reference water level could be reconstructed from sediment grain size. The reconstruction quantitatively extends the regional relative sea-level history to the late Pleistocene, providing a comparatively long dataset to evaluate regional sea-level variability. (3) We find no evidence of a sea-level high stand during MIS3 but rather a substantial regression during 70-30 cal kyr BP and potentially exposed land during 38-20 cal kyr BP. These results for the south Bohai Sea are in good agreement with published global sea-level records for the late Pleistocene, implying similarities between local and global sea-level patterns. Therefore, it is concluded that grain-size based sea-level reconstruction provide results that are comparable to other reconstruction methods and demonstrates great potential application for future works. (The data was shared on http://hurricane.ncdc.noaa.gov/) References Chappell, J., Omura, A., Esat, T., McCulloch, M., Pandolfi, J., Ota, Y., Pillans, B., 1996. Reconciliation of late Quaternary sea levels derived from coral terraces at Huon Peninsula with deep sea oxygen isotope records. Earth and Planetary Science Letters 141, 227-236. Chappell, J., Shackleton, N.J., 1986. Oxygen isotopes and sea level. Nature 324, 137-140. Charman, D.J., Roe, H.M., Roland Gehrels, W., 2002. Modern distribution of saltmarsh testate amoebae: regional variability of zonation and response to environmental variables. Journal of Quaternary Science 17, 387-409. Horton, B.P., 1997. Quantification of the indicative meaning of a range of Holocene sea-level index points from the western North Sea, Department of Geography. University of Durham, Durham City, UK, p. 509. Horton, B.P., Corbett, R., Culver, S.J., Edwards, R.J., Hillier, C., 2006. Modern saltmarsh diatom distributions of the Outer Banks, North Carolina, and the development of a transfer function for high resolution reconstructions of sea level. Estuarine, Coastal and Shelf Science 69, 381-394. IOCAS (Institute of Oceanology, Chinese Academy of Sciences), 1985. Bohai Sea Geology. Science Press, Beijing, China. Madsen, A.T., Murray, A.S., Andersen, T.J., Pejrup, M., 2007. Temporal changes of accretion rates on an estuarine salt marsh during the late Holocene -Reflection of local sea level changes? The Wadden Sea, Denmark. Marine Geology 242, 221-233. Mauz, B., Hassler, U., 2000. Luminescence chronology of Late Pleistocene raised beaches in southern Italy: new data of relative sea-level changes. Marine Geology 170, 187-203. Yi, L., Yu, H.J., Ortiz, J.D., Xu, X.Y., Qiang, X.K., Huang, H.J., Shi, X., Deng, C.L., 2012. A reconstruction of late Pleistocene relative sea level in the south Bohai Sea, China, based on sediment grain-size analysis. Sedimentary Geology 281, 88-100. Zong, Y., Shennan, I., Combellick, R.A., Hamilton, S.L., Rutherford, M.M., 2003. Microfossil evidence for land movements associated with the AD 1964 Alaska earthquake. The Holocene 13, 7-20.

Practical analysis of tide gauges records from Antarctica

NASA Astrophysics Data System (ADS)

Galassi, Gaia; Spada, Giorgio

2015-04-01

We have collected and analyzed in a basic way the currently available time series from tide gauges deployed along the coasts of Antarctica. The database of the Permanent Service for Mean Sea Level (PSMSL) holds relative sea level information for 17 stations, which are mostly concentrated in the Antarctic Peninsula (8 out of 17). For 7 of the PSMSL stations, Revised Local Reference (RLR) monthly and yearly observations are available, spanning from year 1957.79 (Almirante Brown) to 2013.95 (Argentine Islands). For the remaining 11 stations, only metric monthly data can be obtained during the time window 1957-2013. The record length of the available time series is not generally exceeding 20 years. Remarkable exceptions are the RLR station of Argentine Island, located in the Antarctic Peninsula (AP) (time span: 1958-2013, record length: 54 years, completeness=98%), and the metric station of Syowa in East Antarctica (1975-2012, 37 years, 92%). The general quality (geographical coverage and length of record) of the time series hinders a coherent geophysical interpretation of the relative sea-level data along the coasts of Antarctica. However, in an attempt to characterize the relative sea level signals available, we have stacked (i.e., averaged) the RLR time series for the AP and for the whole Antarctica. The so obtained time series have been analyzed using simple regression in order to estimate a trend and a possible sea-level acceleration. For the AP, the the trend is 1.8 ± 0.2 mm/yr and for the whole Antarctica it is 2.1 ± 0.1 mm/yr (both during 1957-2013). The modeled values of Glacial Isostatic Adjustment (GIA) obtained with ICE-5G(VM2) using program SELEN, range between -0.7 and -1.6 mm/yr, showing that the sea-level trend recorded by tide gauges is strongly influenced by GIA. Subtracting the average GIA contribution (-1.1 mm/yr) to observed sea-level trend from the two stacks, we obtain 3.2 and 2.9 mm/yr for Antarctica and AP respectively, which are interpreted as the effect of current ice melting and steric ocean contributions. By the Ensemble Empirical Mode Decomposition method, we have detected different oscillations embedded in the sea-level signals for Antarctica and AP. This confirms previously recognized connections between the sea-level variations in Antarctica and ocean modes like the ENSO.

The Impact of Sea Level Rise on Florida's Everglades

NASA Astrophysics Data System (ADS)

Senarath, S. U.

2005-12-01

Global warming and the resulting melting of polar ice sheets could increase global sea levels significantly. Some studies have predicted mean sea level increases in the order of six inches to one foot in the next 25 to 50 years. This could have severe irreversible impacts on low-lying areas of Florida's Everglades. The key objective of this study is to evaluate the effects of a one foot sea level rise on Cape Sable Seaside Sparrow (CSSS) nesting areas within the Everglades National Park (ENP). A regional-scale hydrologic model is used to assess the sensitivities of this sea-level rise scenario. Florida's Everglades supports a unique ecosystem. At present, about 50 percent of this unique ecosystem has been lost due to urbanization and farming. Today, the water flow in the remnant Everglades is also regulated to meet a variety of competing environmental, water-supply and flood-control needs. A 30-year, eight billion dollar (1999 estimate) project has been initiated to improve Everglades' water flows. The expected benefits of this restoration project will be short-lived if the predicted sea level rise causes severe impacts on the environmentally sensitive areas of the Everglades. Florida's Everglades is home to many threatened and endangered species of wildlife. The Cape Sable Seaside Sparrow population in the ENP is one such species that is currently listed as endangered. Since these birds build their nests close to the ground surface (the base of the nest is approximately six inches from the ground surface), they are directly affected by any sea level induced ponding depth, frequency or duration change. Therefore, the CSSS population serves as a good indicator species for evaluating the negative impacts of sea level rise on the Everglades' ecosystem. The impact of sea level rise on the CSSS habitat is evaluated using the Regional Simulation Model (RSM) developed by the South Florida Water Management District. The RSM is an implicit, finite-volume, continuous, distributed, and integrated surface-water and ground-water model. It can simulate one-dimensional canal/stream flow and two-dimensional overland and groundwater flow in arbitrarily shaped areas using a variable triangular mesh. The overland and groundwater flow components are fully coupled in the RSM for a more realistic representation of runoff generation.

Land Sea Level Difference Impacts on Socio-Hydrological System.

NASA Astrophysics Data System (ADS)

Sung, K.; Yu, D. J.; Oh, W. S.; Sangwan, N.

2016-12-01

Allowing moderate shocks can be a new solution that helps to build adaptive capacity in society is a rising issue. In Social-Ecological field, Carpenter et al. (2015) suggested that exposure to short-term variability leads to long term resilience by enlarging safe operating space (SOS). The SOS refers to the boundary of favorable state that ecosystem can maintain resilience without imposing certain conditions (Carpenter et al. 2015). Our work is motivated by defining SOS in socio-hydrological system(SHS) because it can be an alternative way for flood management beyond optimized or robust flood control. In this context, large flood events that make system to cross the SOS should be fully managed, but frequent small floods need to be allowed if the system is located in SOS. Especially, land sea level change is critical factor to change flood resilience since it is one of the most substantial disturbance that changes the entire boundary of SOS. In order to have broader perspective of vulnerability and resilience of the coastal region, it is crucial to understand the land sea level dynamics changed with human activities and natural variances.The risk of land sea level change has been researched , but most of these researches have focused on explain cause and effect of land sea level change, paying little attention to its dynamics interacts with human activities. Thus, an objective of this research is to study dynamics of human work, land sea level change and resilience to flood with SOS approach. Especially, we focus on the case in Ganges-Brahmaputra, Bangladesh where has high vulnerability to flood, and is faced with relatively rapid land sea level change problem. To acheive the goal, this study will develop a stylized model by extending the human - flood interaction model combined with relative sea level difference equation. The model describes the dynamics of flood protection system which is changed by SHS and land sea level chage. we will focus on the aggradation and human compaction which are highly chaged by human-flood interactions. Carpenter, S. R., W. A. Brock, C. Folke, E. H. van Nes, and M. Scheffer. 2015. Allowing variance may enlarge the safe operating space for exploited ecosystems. Proceedings of the National Academy of Sciences 112(46):14384-14389.

Climate related sea-level variations over the past two millennia

PubMed Central

Kemp, Andrew C.; Horton, Benjamin P.; Donnelly, Jeffrey P.; Mann, Michael E.; Vermeer, Martin; Rahmstorf, Stefan

2011-01-01

We present new sea-level reconstructions for the past 2100 y based on salt-marsh sedimentary sequences from the US Atlantic coast. The data from North Carolina reveal four phases of persistent sea-level change after correction for glacial isostatic adjustment. Sea level was stable from at least BC 100 until AD 950. Sea level then increased for 400 y at a rate of 0.6 mm/y, followed by a further period of stable, or slightly falling, sea level that persisted until the late 19th century. Since then, sea level has risen at an average rate of 2.1 mm/y, representing the steepest century-scale increase of the past two millennia. This rate was initiated between AD 1865 and 1892. Using an extended semiempirical modeling approach, we show that these sea-level changes are consistent with global temperature for at least the past millennium. PMID:21690367

Long-term sea level trends: Natural or anthropogenic?

NASA Astrophysics Data System (ADS)

Becker, M.; Karpytchev, M.; Lennartz-Sassinek, S.

2014-08-01

Detection and attribution of human influence on sea level rise are important topics that have not yet been explored in depth. We question whether the sea level changes (SLC) over the past century were natural in origin. SLC exhibit power law long-term correlations. By estimating Hurst exponent through Detrended Fluctuation Analysis and by applying statistics of Lennartz and Bunde, we search the lower bounds of statistically significant external sea level trends in longest tidal records worldwide. We provide statistical evidences that the observed SLC, at global and regional scales, is beyond its natural internal variability. The minimum anthropogenic sea level trend (MASLT) contributes to the observed sea level rise more than 50% in New York, Baltimore, San Diego, Marseille, and Mumbai. A MASLT is about 1 mm/yr in global sea level reconstructions that is more than half of the total observed sea level trend during the XXth century.

Quantitative analysis of Paratethys sea level change during the Messinian Salinity Crisis

NASA Astrophysics Data System (ADS)

de la Vara, Alba; Meijer, Paul; van Baak, Christiaan; Marzocchi, Alice; Grothe, Arjen

2016-04-01

At the time of the Messinian Salinity Crisis in the Mediterranean Sea (i.e., the Pontian stage of the Paratethys), the Paratethys sea level dropped also. Evidence found in the sedimentary record of the Black Sea and the Caspian Sea has been interpreted to indicate that a sea level fall occurred between 5.6 and 5.5 Ma. Estimates for the magnitude of the fall range between tens of meters to more than 1500 m. The purpose of this study is to provide quantitative insight into the sensitivity of the water level of the Black Sea and the Caspian Sea to the hydrologic budget, for the case that the Paratethys is disconnected from the Mediterranean. Using a Late Miocene bathymetry based on a palaeographic map by Popov et al. (2004) we quantify the fall in sea level, the mean salinity, and the time to reach equilibrium for a wide range of negative hydrologic budgets. By combining our results with (i) estimates derived from a recent global Late Miocene climate simulation and (ii) reconstructed basin salinities, we are able to rule out a drop in sea level of the order of 1000 m in the Caspian Sea during this time period. In the Black Sea, however, such a large sea level fall cannot be fully discarded.

Sea level budget in the Arctic during the satellite altimetry era

NASA Astrophysics Data System (ADS)

Carret, Alice; Cazenave, Anny; Meyssignac, Benoît; Prandi, Pierre; Ablain, Michael; Andersen, Ole; Blazquez, Alejandro

2016-04-01

Studying sea level variations in the Arctic region is challenging because of data scarcity. Here we present results of the sea level budget in the Arctic (up to 82°N) during the altimetry era. We first investigate closure of the sea level budget since 2002 using altimetry data from Envisat and Cryosat for estimating sea level, temperature and salinity data from the ORAP5 reanalysis and GRACE space gravimetry to estimate the steric and mass components. Two altimetry sea level data sets are considered (from DTU and CLS), based on Envisat waveforms retracking. Regional sea level trends seen in the altimetric map, in particular over the Beaufort Gyre and along the eastern coast of Greenland are of steric origin. However, in terms of regional average, the steric component contributes very little to the observed sea level trend, suggesting a dominant mass contribution in the Arctic region. This is confirmed by GRACE-based ocean mass time series that agree very well with the altimetry-based sea level time series. Direct estimate of the mass component is not possible prior to GRACE. Thus we estimated the mass contribution over the whole altimetry era from the difference between altimetry-based sea level and the ORAP5 steric component. Finally we compared altimetry-based coastal sea level with tide gauge records available along Norwegian, Greenland and Siberian coastlines and investigated whether the Arctic Oscillation that was the main driver of coastal sea level in the Arctic during the past decades still plays a dominant role or if other factors (e.g., of anthropogenic origin) become detectable.

Generalized Cauchy model of sea level fluctuations with long-range dependence

NASA Astrophysics Data System (ADS)

Li, Ming; Li, Jia-Yue

2017-10-01

This article suggests the contributions with two highlights. One is to propose a novel model of sea level fluctuations (sea level for short), which is called the generalized Cauchy (GC) process. It provides a new outlook for the description of local and global behaviors of sea level from a view of fractal in that the fractal dimension D that measures the local behavior of sea level and the Hurst parameter H which characterizes the global behavior of sea level are independent of each other. The other is to show that sea level appears multi-fractal in both spatial and time. Such a meaning of multi-fractal is new in the sense that a pair of fractal parameters (D, H) of sea level is varying with measurement sites and time. This research exhibits that the ranges of D and H of sea level, in general, are 1 ≤ D < 2 and 0 . 5 < H < 1, respectively but D is independent of H. With respect to the global behavior of sea level, we shall show that H > 0 . 96 for all data records at all measurement sites, implying that strong LRD may be a general phenomenon of sea level. On the other side, regarding with the local behavior, we will reveal that there appears D = 1 or D ≈ 1 for data records at a few stations and at some time, but D > 0 . 96 at most stations and at most time, meaning that sea level may appear highly local irregularity more frequently than weak local one.

Inception of a global atlas of Holocene sea levels

NASA Astrophysics Data System (ADS)

Khan, Nicole; Rovere, Alessio; Engelhart, Simon; Horton, Benjamin

2017-04-01

Determining the rates, mechanisms and geographic variability of sea-level change is a priority science question for the next decade of ocean research. To address these research priorities, the HOLocene SEA-level variability (HOLSEA) working group is developing the first standardized global synthesis of Holocene relative sea-level data to: (1) estimate the magnitudes and rates of global mean sea-level change during the Holocene; and (2) identify trends in spatial variability and decipher the processes responsible for geographic differences in relative sea-level change. Here we present the preliminary efforts of the working group to compile the database, which includes sea-level index points and limiting data from a range of different indicators across seven continents from the Last Glacial Maximum to present. We follow a standard protocol that incorporates full consideration of vertical and temporal uncertainty for each sea-level index point, including uncertainties associated with the relationship of each indicator to past sea-level and the methods used to date each indicator. We describe the composition of the global database, identify gaps in data availability, and highlight our effort to create an online platform to access the data. These data will be made available in a special issue of Quaternary Science Reviews and archived on NOAA's National Centers for Environmental Information (NCEI) in early 2018. We also invite researchers who collect or model Holocene sea-level data to participate. Long-term, this effort will enhance predictions of 21st century sea-level rise, and provide a vital contribution to the assessment of natural hazards with respect to sea-level rise and coastal response.

Global Climate Change Consequences Changing the Middle Sea Level in the Brazilian Coast: Impacts on Ceará State

NASA Astrophysics Data System (ADS)

Lacerda, E. G.; Pires, L. B. M.; Pinto, V. K. E.

2015-12-01

Since the Industrial Revolution, man started to generate increasing amounts of waste and pollutants, which on a large scale in the long term is causing a series of climate change consequences, both globally as well as locally. One of the many effects of these changes has been reflected in the ocean levels, depending on various factors. Thus, the population living in coastal areas suffers from the negative effects of the advancement of ocean waters. The coast of northeastern Brazil is an example of this, especially the state of Ceará coast. The state of Ceará has 573 km of coastline, a region that has suffered extensive erosion, in which the Middle Sea Level (MSL) changes exert a significant influence. The coastal plain is a strip of land of small extent, with an average width of 2.5 km, formed depending on the availability of high sediment stocks provided through the action of wind, marine, or river processes, individually in combination with each other. In many beaches it is observed that the strip of beach is narrow due to the presence of topographic elevations carved into sharp cliffs. Between periods of high tide and low tide, often rocky beach features are observed that have recently formed. The waves control the stretches of beach which are mostly sandy. This paper presents a survey about the evidence already apparent on the rise in the MSL and correlates it with the advance of the sea on the coast of Ceará, as well as assesses the possible consequences of this process. Therefore, a literature search was conducted in relevant scientific publications. The data used are from the station "Global Sea Level Observing System - GLOSS" which maintains a tide gauge installed in Ceará in Fortaleza. The analyses show that the phenomenon has caused a lot of inconvenience to the people, streets have disappeared, as well as several buildings located along the coast. The sea advances destroyed beaches and have promoted an accelerated level of erosion, changing the landscape of the region significantly. Data collected between 1996 and 2006 show that the sea height demonstrated a significant increase, especially from 2000. Keywords: Climate Change, Middle Sea Level, Ceará Coastline.Since the Industrial Revolution, man started to generate increasing amounts of waste and pollutants, which on a large scale in the long term is causing a series of climate change consequences, both globally as well as locally. One of the many effects of these changes has been reflected in the ocean levels, depending on various factors. Thus, the population living in coastal areas suffers from the negative effects of the advancement of ocean waters. The coast of northeastern Brazil is an example of this, especially the state of Ceará coast. The state of Ceará has 573 km of coastline, a region that has suffered extensive erosion, in which the Middle Sea Level (MSL) changes exert a significant influence. The coastal plain is a strip of land of small extent, with an average width of 2.5 km, formed depending on the availability of high sediment stocks provided through the action of wind, marine, or river processes, individually in combination with each other. In many beaches it is observed that the strip of beach is narrow due to the presence of topographic elevations carved into sharp cliffs. Between periods of high tide and low tide, often rocky beach features are observed that have recently formed. The waves control the stretches of beach which are mostly sandy. This paper presents a survey about the evidence already apparent on the rise in the MSL and correlates it with the advance of the sea on the coast of Ceará, as well as assesses the possible consequences of this process. Therefore, a literature search was conducted in relevant scientific publications. The data used are from the station "Global Sea Level Observing System - GLOSS" which maintains a tide gauge installed in Ceará in Fortaleza. The analyses show that the phenomenon has caused a lot of inconvenience to the people, streets have disappeared, as well as several buildings located along the coast. The sea advances destroyed beaches and have promoted an accelerated level of erosion, changing the landscape of the region significantly. Data collected between 1996 and 2006 show that the sea height demonstrated a significant increase, especially from 2000. Keywords: Climate Change, Middle Sea Level, Ceará Coastline.

Predicting habitat distribution to conserve seagrass threatened by sea level rise

NASA Astrophysics Data System (ADS)

Saunders, M. I.; Baldock, T.; Brown, C. J.; Callaghan, D. P.; Golshani, A.; Hamylton, S.; Hoegh-guldberg, O.; Leon, J. X.; Lovelock, C. E.; Lyons, M. B.; O'Brien, K.; Mumby, P.; Phinn, S. R.; Roelfsema, C. M.

2013-12-01

Sea level rise (SLR) over the 21st century will cause significant redistribution of valuable coastal habitats. Seagrasses form extensive and highly productive meadows in shallow coastal seas support high biodiversity, including economically valuable and threatened species. Predictive habitat models can inform local management actions that will be required to conserve seagrass faced with multiple stressors. We developed novel modelling approaches, based on extensive field data sets, to examine the effects of sea level rise and other stressors on two representative seagrass habitats in Australia. First, we modelled interactive effects of SLR, water clarity and adjacent land use on estuarine seagrass meadows in Moreton Bay, Southeast Queensland. The extent of suitable seagrass habitat was predicted to decline by 17% by 2100 due to SLR alone, but losses were predicted to be significantly reduced through improvements in water quality (Fig 1a) and by allowing space for seagrass migration with inundation. The rate of sedimentation in seagrass strongly affected the area of suitable habitat for seagrass in sea level rise scenarios (Fig 1b). Further research to understand spatial, temporal and environmental variability of sediment accretion in seagrass is required. Second, we modelled changes in wave energy distribution due to predicted SLR in a linked coral reef and seagrass ecosystem at Lizard Island, Great Barrier Reef. Scenarios where the water depth over the coral reef deepened due to SLR and minimal reef accretion, resulted in larger waves propagating shoreward, changing the existing hydrodynamic conditions sufficiently to reduce area of suitable habitat for seagrass. In a scenario where accretion of the coral reef was severely compromised (e.g. warming, acidification, overfishing), the probability of the presence of seagrass declined significantly. Management to maintain coral health will therefore also benefit seagrasses subject to SLR in reef environments. Further disentangling direct and indirect effects of climate change on seagrass will be necessary to inform management of these valuable coastal ecosystems. Models such as these will be important sources of information for management agencies, which require specific information on the likely impacts of sea level rise in coastal areas.

Sea-level and deep-sea-temperature variability over the past 5.3 million years.

PubMed

Rohling, E J; Foster, G L; Grant, K M; Marino, G; Roberts, A P; Tamisiea, M E; Williams, F

2014-04-24

Ice volume (and hence sea level) and deep-sea temperature are key measures of global climate change. Sea level has been documented using several independent methods over the past 0.5 million years (Myr). Older periods, however, lack such independent validation; all existing records are related to deep-sea oxygen isotope (δ(18)O) data that are influenced by processes unrelated to sea level. For deep-sea temperature, only one continuous high-resolution (Mg/Ca-based) record exists, with related sea-level estimates, spanning the past 1.5 Myr. Here we present a novel sea-level reconstruction, with associated estimates of deep-sea temperature, which independently validates the previous 0-1.5 Myr reconstruction and extends it back to 5.3 Myr ago. We find that deep-sea temperature and sea level generally decreased through time, but distinctly out of synchrony, which is remarkable given the importance of ice-albedo feedbacks on the radiative forcing of climate. In particular, we observe a large temporal offset during the onset of Plio-Pleistocene ice ages, between a marked cooling step at 2.73 Myr ago and the first major glaciation at 2.15 Myr ago. Last, we tentatively infer that ice sheets may have grown largest during glacials with more modest reductions in deep-sea temperature.

Potential adverse health effects of persistent organic pollutants on sea turtles: evidences from a cross-sectional study on Cape Verde loggerhead sea turtles.

PubMed

Camacho, María; Luzardo, Octavio P; Boada, Luis D; López Jurado, Luis F; Medina, María; Zumbado, Manuel; Orós, Jorge

2013-08-01

The Cape Verde nesting population of loggerhead sea turtles (Caretta caretta) is the third largest population of this species in the world. For conservation purposes, it is essential to determine how these reptiles respond to different types of anthropogenic contaminants. We evaluated the presence of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs) in the plasma of adult nesting loggerheads from Boa Vista Island, Cape Verde, and studied the effects of the contaminants on the health status of the turtles using hematological and biochemical parameters. All turtles had detectable levels of non-dioxin like PCBs, whereas dioxin-like congeners (DL-PCBs) were detected in only 30% of the turtles. Packed cell volume decreased with higher concentrations of PCBs, which suggests that PCB exposure could result in anemia in sea turtles. In addition, a negative association between some OCPs and white blood cells (WBC) and thrombocyte estimate was noted. The DDT-metabolite, p,p'-DDE was negatively correlated with the Na/K ratio and, additionally, a number of correlations between certain PAHs and electrolyte balances were found, which suggest that exposure to these environmental contaminants could affect the kidneys and salt glands in sea turtles. Additionally, several correlations were observed between these environmental pollutants (OCPs and PAHs) and enzyme activity (GGT, ALT, ALP and amylase) and serum protein levels, pointing to the possibility that these contaminants could induce adverse metabolic effects in sea turtles. Our results indicate that anthropogenic pollutants are present in the Cape Verde loggerhead turtle nesting population and could exert negative effects on several health parameters. Because of the importance of this loggerhead nesting population, protective regulations at national and international levels as well as international action are necessary for assuring the conservation of this population. Copyright © 2013 Elsevier B.V. All rights reserved.

Improving sea level simulation in Mediterranean regional climate models

NASA Astrophysics Data System (ADS)

Adloff, Fanny; Jordà, Gabriel; Somot, Samuel; Sevault, Florence; Arsouze, Thomas; Meyssignac, Benoit; Li, Laurent; Planton, Serge

2017-08-01

For now, the question about future sea level change in the Mediterranean remains a challenge. Previous climate modelling attempts to estimate future sea level change in the Mediterranean did not meet a consensus. The low resolution of CMIP-type models prevents an accurate representation of important small scales processes acting over the Mediterranean region. For this reason among others, the use of high resolution regional ocean modelling has been recommended in literature to address the question of ongoing and future Mediterranean sea level change in response to climate change or greenhouse gases emissions. Also, it has been shown that east Atlantic sea level variability is the dominant driver of the Mediterranean variability at interannual and interdecadal scales. However, up to now, long-term regional simulations of the Mediterranean Sea do not integrate the full sea level information from the Atlantic, which is a substantial shortcoming when analysing Mediterranean sea level response. In the present study we analyse different approaches followed by state-of-the-art regional climate models to simulate Mediterranean sea level variability. Additionally we present a new simulation which incorporates improved information of Atlantic sea level forcing at the lateral boundary. We evaluate the skills of the different simulations in the frame of long-term hindcast simulations spanning from 1980 to 2012 analysing sea level variability from seasonal to multidecadal scales. Results from the new simulation show a substantial improvement in the modelled Mediterranean sea level signal. This confirms that Mediterranean mean sea level is strongly influenced by the Atlantic conditions, and thus suggests that the quality of the information in the lateral boundary conditions (LBCs) is crucial for the good modelling of Mediterranean sea level. We also found that the regional differences inside the basin, that are induced by circulation changes, are model-dependent and thus not affected by the LBCs. Finally, we argue that a correct configuration of LBCs in the Atlantic should be used for future Mediterranean simulations, which cover hindcast period, but also for scenarios.

Wetland Accretion Rate Model of Ecosystem Resilience (WARMER) and its application to habitat sustainability for endangered species in the San Francisco Estuary

USGS Publications Warehouse

Swanson, Kathleen M.; Drexler, Judith Z.; Schoellhamer, David H.; Thorne, Karen M.; Casazza, Michael L.; Overton, Cory T.; Callaway, John C.; Takekawa, John Y.

2014-01-01

Salt marsh faunas are constrained by specific habitat requirements for marsh elevation relative to sea level and tidal range. As sea level rises, changes in relative elevation of the marsh plain will have differing impacts on the availability of habitat for marsh obligate species. The Wetland Accretion Rate Model for Ecosystem Resilience (WARMER) is a 1-D model of elevation that incorporates both biological and physical processes of vertical marsh accretion. Here, we use WARMER to evaluate changes in marsh surface elevation and the impact of these elevation changes on marsh habitat for specific species of concern. Model results were compared to elevation-based habitat criteria developed for marsh vegetation, the endangered California clapper rail (Rallus longirostris obsoletus), and the endangered salt marsh harvest mouse (Reithrodontomys raviventris) to determine the response of marsh habitat for each species to predicted >1-m sea-level rise by 2100. Feedback between vertical accretion mechanisms and elevation reduced the effect of initial elevation in the modeled scenarios. Elevation decreased nonlinearly with larger changes in elevation during the latter half of the century when the rate of sea-level rise increased. Model scenarios indicated that changes in elevation will degrade habitat quality within salt marshes in the San Francisco Estuary, and degradation will accelerate in the latter half of the century as the rate of sea-level rise accelerates. A sensitivity analysis of the model results showed that inorganic sediment accumulation and the rate of sea-level rise had the greatest influence over salt marsh sustainability.

Effects of Sea Level Rise on Groundwater Flow Paths in a Coastal Aquifer System

NASA Astrophysics Data System (ADS)

Morrissey, S. K.; Clark, J. F.; Bennett, M. W.; Richardson, E.; Stute, M.

2008-05-01

Changes in groundwater flow in the Floridan aquifer system, South Florida, from the rise in sea level at the end of the last glacial period may be indicative of changes coastal aquifers will experience with continued sea level rise. As sea level rises, the hydraulic head near the coast increases. Coastal aquifers can therefore experience decreased groundwater gradients (increased residence times) and seawater intrusion. Stable isotopes of water, dissolved noble gas temperatures, radiocarbon and He concentrations were analyzed in water collected from 68 wells in the Floridan aquifer system throughout South Florida. Near the recharge area, geochemical data along groundwater flow paths in the Upper Floridan aquifer show a transition from recently recharged groundwater to glacial-aged water. Down gradient from this transition, little variation is apparent in the stable isotopes and noble gas recharge temperatures, indicating that most of the Upper Floridan aquifer contains groundwater recharged during the last glacial period. The rapid 120-meter rise in sea level marking the end of the last glacial period increased the hydraulic head in the Floridan aquifer system near the coast, slowing the flow of groundwater from the recharge area to the ocean and trapping glacial-aged groundwater. The raised sea level also flooded half of the Florida platform and caused seawater to intrude into the Lower Floridan. This circulation of seawater in the Lower Floridan continues today as our data indicate that the groundwater is similar to modern seawater with a freshwater component entering vertically from the recharge area to the Upper Floridan.

Great Britain Storm Surge Modeling for a 10,000-Year Stochastic Catalog with the Effect of Sea Level Rise

NASA Astrophysics Data System (ADS)

Keshtpoor, M.; Carnacina, I.; Blair, A.; Yablonsky, R. M.

2017-12-01

Storm surge caused by Extratropical Cyclones (ETCs) has significantly impacted not only the life of private citizens but also the insurance and reinsurance industry in Great Britain. The storm surge risk assessment requires a larger dataset of storms than the limited recorded historical ETCs. Thus, historical ETCs were perturbed to generate a 10,000-year stochastic catalog that accounts for surge-generating ETCs in the study area with return periods from one year to 10,000 years. Delft3D-Flexible Mesh hydrodynamic model was used to numerically simulate the storm surge along the Great Britain coastline. A nested grid technique was used to increase the simulation grid resolution up to 200 m near the highly populated coastal areas. Coarse and fine mesh models were calibrated and validated using historical recorded water elevations. Then, numerical simulations were performed on a 10,000-year stochastic catalog. The 50-, 100-, and 500-year return period maps were generated for Great Britain coastal areas. The corresponding events with return periods of 50-, 100-, and 500-years in Humber Bay and Thames River coastal areas were identified, and simulated with the consideration of projected sea level rises to reveal the effect of rising sea levels on the inundation return period maps in two highly-populated coastal areas. Finally, the return period of Storm Xaver (2013) was determined with and without the effect of rising sea levels.

The Impact of Water Loading on Estimates of Postglacial Decay Times in Hudson Bay

NASA Astrophysics Data System (ADS)

Han, H. K.; Gomez, N. A.

2016-12-01

Ongoing glacial isostatic adjustment (GIA) due to surface loading (ice and water) variations since the Last Glacial Maximum (LGM) has been contributing to sea level changes globally throughout the Holocene, especially in regions like the Canada that were heavily glaciated during the LGM. The spatial and temporal distribution of GIA and relative sea level change are attributed to the ice history and the rheological structure of the solid Earth, both of which are uncertain. It has been shown that relative sea level curves in previously glaciated regions follow an exponential-like form, and the post glacial decay times associated with that form have weak sensitivity to the details of the ice loading history (Andrews 1970, Walcott 1980, Mitrovica & Peltier 1995). Post glacial decay time estimates may therefore be used to constrain the Earth's structure and improve GIA predictions. However, estimates of decay times in Hudson Bay in the literature differ significantly due to a number of sources of uncertainty and bias (Mitrovica et al. 2000). Previous decay time analyses have not considered the potential bias that surface loading associated with Holocene sea level changes can introduce in decay time estimates derived from nearby relative sea level observations. We explore the spatial patterns of post glacial decay time predictions in previously glaciated regions, and their sensitivity to ice and water loading history. We compute post glacial sea level changes over the last deglaciation from 21ka to the modern associated with the ICE5G (Peltier, 2004) and ICE6G (Argus et al. 2014, Peltier et al. 2015) ice history models. We fit exponential curves to the modeled relative sea level changes, and compute maps of post glacial decay time predictions across North America and the Arctic. In addition, we decompose the modeled relative sea level changes into contributions from water and ice loading effects, and compute the impact of water loading redistribution since the LGM on present day decay times. We show that Holocene water loading in the Hudson Bay may introduce significant bias in decay time estimates and we highlight locations where biases are minimized.

Glacio-isostasy and Glacial Ice Load at Law Dome, Wilkes Land, East Antarctica

NASA Astrophysics Data System (ADS)

Goodwin, Ian D.; Zweck, Christopher

2000-05-01

The Holocene sea-level high stand or "marine limit" in Wilkes Land, East Antarctica, reached ˜30 m above present sea level at a few dispersed sites. The most detailed marine limit data have been recorded for the Windmill Islands and Budd Coast at the margin of the Law Dome ice cap, a dome of the East Antarctic Ice Sheet (EAIS). Relative sea-level lowering of 30 m and the associated emergence of the Windmill Islands have occurred since 6900 14C (corr.) yr B.P. Numerical modeling of the Earth's rheology is used to determine the glacio-isostatic component of the observed relative sea-level lowering. Glaciological evidence suggests that most of EAIS thickening occurred around its margin, with expansion onto the continental shelf. Consequently, a regional ice history for the last glacial maximum (LGM) was applied in the glacio-isostatic modeling to test whether the observed relative sea-level lowering was primarily produced by regional ice-sheet changes. The results of the modeling indicate that the postglacial (13,000 to 8000 14C yr B.P) removal of an ice load of between 770 and 1000 m from around the margin of the Law Dome and adjacent EAIS have produced the observed relative sea-level lowering. Such an additional ice load would have been associated with a 40- to 65-km expansion of the Law Dome to near the continental shelf break, together with a few hundred meters of ice thickening on the adjoining coastal slope of the EAIS up to 2000 m elevation. Whereas the observed changes in relative sea level are shown to be strongly influenced by regional ice sheet changes, the glacio-isostatic response at the Windmill Islands results from a combination of regional and, to a lesser extent, Antarctic-wide effects. The correspondence between the Holocene relative sea-level lowering interpreted at the margin of the Law Dome and the lowering interpreted along the remainder of the Wilkes Land and Oates Land coasts (105°-160° E) suggests that a similar ice load of up to 1000 m existed along the EAIS margin between Wilkes Land and Oates Land.

Effect of specific pathways to 1.5°C global warming on the contribution of Greenland to sea level rise

NASA Astrophysics Data System (ADS)

Humbert, A.; Rückamp, M.; Falk, U.; Frieler, K.

2017-12-01

Sea level rise associated with changing climate is expected to pose a major challenge for societies. Here, we estimate the future contribution of the Greenland ice sheet (GrIS) to sea level change in terms of different emission scenarios. We investigate the effect of different pathways of global warming on the dynamics and mass balance of the GrIS with a focus on scenarios in line with limiting global warming to 2.0° or even 1.5° by the end of 2100 (Paris Agreement). We particularly address the issue of peak and decline scenarios temporarily exceeding a given temperature limit. This kind of overshooting might have strong effects on the evolution of the GrIS. Furthermore, we investigate the long-term effects of different levels of climate change to estimate the threshold for stabilizing the GrIS. For modeling the flow dynamics and future evolution of the GrIS, we apply the thermo-mechanical coupled Ice Sheet System Model (ISSM). The model is forced with anomalies for temperature and surface mass balance derived from different GCM data from the CMIP5 RCP2.6 scenario provided from the ISIMIP2b project. In order to obtain these anomalies from the GCM data, a surface energy balance model is applied.

Hydrologic conditions in urban Miami-Dade County, Florida, and the effect of groundwater pumpage and increased sea level on canal leakage and regional groundwater flow

USGS Publications Warehouse

Hughes, Joseph D.; White, Jeremy T.

2014-01-01

The model was designed specifically to evaluate the effect of groundwater pumpage on canal leakage at the surface-water-basin scale and thus may not be appropriate for (1) predictions that are dependent on data not included in the calibration process (for example, subdaily simulation of high-intensity events and travel times) and (or) (2) hydrologic conditions that are substantially different from those during the calibration and verification periods. The reliability of the model is limited by the conceptual model of the surface-water and groundwater system, the spatial distribution of physical properties, the scale and discretization of the system, and specified boundary conditions. Some of the model limitations are manifested in model errors. Despite these limitations, however, the model represents the complexities of the interconnected surface-water and groundwater systems that affect how the systems respond to groundwater pumpage, sea-level rise, and other hydrologic stresses. The model also quantifies the relative effects of groundwater pumpage and sea-level rise on the surface-water and groundwater systems.

Quantifying and Projecting Relative Sea-Level Rise At The Regional Scale: The Bangladesh Sea-Level Project (BanD-AID)

NASA Astrophysics Data System (ADS)

Shum, C. K.; Kuo, C. Y.; Guo, J.; Shang, K.; Tseng, K. H.; Wan, J.; Calmant, S.; Ballu, V.; Valty, P.; Kusche, J.; Hossain, F.; Khan, Z. H.; Rietbroek, R.; Uebbing, B.

2014-12-01

The potential for accelerated sea-level rise under anthropogenic warming is a significant societal problem, in particular in world's coastal deltaic regions where about half of the world's population resides. Quantifying geophysical sources of sea-level rise with the goal of improved projection at local scales remains a complex and challenging interdisciplinary research problem. These processes include ice-sheet/glacier ablations, steric sea-level, solid Earth uplift or subsidence due to GIA, tectonics, sediment loading or anthropogenic causes, hydrologic imbalance, and human processes including water retention in reservoirs and aquifer extraction. The 2013 IPCC AR5 concluded that the observed and explained geophysical causes of global geocentric sea-level rise, 1993-2010, is closer towards closure. However, the discrepancy reveals that circa 1.3→37.5% of the observed sea-level rise remains unexplained. This relatively large discrepancy is primarily attributable to the wide range of estimates of respective contributions of Greenland and Antarctic ice-sheets and mountain/peripheral glaciers to sea-level rise. Understanding and quantifying the natural and anthropogenic processes governing solid Earth (land, islands and sea-floor) uplift or subsidence at the regional and local scales remain elusive to enable addressing coastal vulnerability due to relative sea-level rise hazards, such as the Bangladesh Delta. This study focuses on addressing coastal vulnerability of Bangladesh, a Belmont Forum/IGFA project, BanD-AID (http://Belmont-SeaLevel.org). Sea-level rise, along with tectonic, sediment load and groundwater extraction induced land uplift/subsidence, have exacerbated Bangladesh's coastal vulnerability, affecting 150 million people in one of the world's most densely populated regions. Here we present preliminary results using space geodetic observations, including satellite radar and laser altimetry, GRACE gravity, tide gauge, hydrographic, and GPS/InSAR observed land subsidence, and via fingerprint sea-level adjustment and reconstructed sea-level approaches, for improved quantification of major contributions to, and the projection of relative sea-level rise at the Bangladesh delta, towards addressing its coastal vulnerability and sustainability.

Deciphering The Fall And Rise Of The Dead Sea In Relation To Solar Forcing

NASA Astrophysics Data System (ADS)

Yousef, Shahinaz M.

2005-03-01

Solar Forcing on closed seas and Lakes is space time dependent. The Cipher of the Dead Sea level variation since 1200 BC is solved in the context of millenium and Wolf-Gleissberg solar cycles time scales. It is found that the pattern of Dead Sea level variation follows the pattern of major millenium solar cycles. The 70 m rise of Dead Sea around 1AD is due to the forcing of the maximum millenium major solar cycle. Although the pattern of the Dead Sea level variation is almost identical to major solar cycles pattern between 1100 and 1980 AD, there is a dating problem of the Dead Sea time series around 1100-1300 AD that time. A discrepancy that should be corrected for the solar and Dead Sea series to fit. Detailed level variations of the Dead Sea level for the past 200 years are solved in terms of the 80-120 years solar Wolf-Gliessberg magnetic cycles. Solar induced climate changes do happen at the turning points of those cycles. Those end-start and maximum turning points are coincident with the change in the solar rotation rate due to the presence of weak solar cycles. Such weak cycles occur in series of few cycles between the end and start of those Wolf-Gleissberg cycles. Another one or two weak r solar cycle occur following the maximum of those Wolf-Gleissberg cycles. Weak cycles induce drop in the energy budget emitted from the sun and reaching the Earth thus causing solar induced climate change. An 8 meter sudden rise of Dead Sea occur prior 1900 AD due to positive solar forcing of the second cycle of the weak cycles series on the Dead Sea. The same second weak cycle induced negative solar forcing on Lake Chad. The first weak solar cycle forced Lake Victoria to rise abruptly in 1878. The maximum turning point of the solar Wolf-Gleissberg cycle induced negative forcing on both the Aral Sea and the Dead Sea causing their shrinkage to an alarming reduced area ever since. On the other hand, few years delayed positive forcing caused Lake Chad and the Equatorial African lakes to rise abruptly by several meters. Since the present solar cycle number 23 is the first weak cycle of a series, and since it caused 1.6 m sharp rise in Lake Victoria in 1997, then there is a high probability that the Dead Sea will rise by the beginning of the second weak cycle in few years time. And since both the Aral Sea and the Dead Sea are very much in coherence since the late 1950s, then it is rather likely that the Aral Sea will rise with God's wish in the near future. However it is also demanded that Israel should allow more water of the Jordan River to feed the Dead Sea before its real death. Plans for joining the Dead sea to the Red and or to the Mediterranean Seas should be cancelled owing the damaging harm it will cause the Dead Sea as a perfect indicator of solar induced climate change on one hand. On the other hand, the Dead Sea time series always show abrupt changes that can be as high as 70 m; if we add to this a planned artificial rise of the Dead Sea to its level of the thirties, then a damaging flooding effect will ruin the establishments and environment greatly.

Sea-level and climate forcing of the Sr isotope composition of marginal basins in the late Miocene Mediterranean Basin

NASA Astrophysics Data System (ADS)

Schildgen, T. F.; Cosentino, D.; Frijia, G.; Castorina, F.; Dudas, F. O.; Iadanza, A.; Cipollari, P.; Caruso, A.; Bowring, S. A.; Strecker, M. R.

2013-12-01

Sr isotope records from marginal marine basins track the mixing between sea water and local continental runoff. Because changes in sea level determine the amount of mixing between global marine and continental water, and climate affects the amount of continental runoff, both sea-level and climate changes can potentially be recorded in marine fossil Sr isotope composition. Our 128 new 87Sr/86Sr analyses on 73 oyster, foraminifera, and coral samples from eight late Miocene stratigraphic sections in southern Turkey, Crete, and Sicily show that 87Sr/86Sr in Mediterranean marginal basins started to depart from global ocean values several million years before the Messinian Salinity Crisis (MSC), with sub-basin 87Sr/86Sr commonly dropping 0.000100 below contemporaneous global ocean values. The marked departure coincided with tectonic uplift and basin shallowing along the margins of the Mediterranean Basin. In contrast, centrally-located basins within the Mediterranean (e.g., Cyprus, Sicily, Crete) only record departures during the MSC. Besides this general trend, our 57 new 87Sr/86Sr analyses from the astronomically tuned Lower Evaporite unit deposited during the MSC in the central Apennines (Italy) allow us to explore in detail the effect of sea-level and humidity changes on 87Sr/86Sr . Most of the variation in 87Sr/86Sr that we observe can be explained by changes in eustatic sea level, with greatest departures from global ocean values (with differences up to 0.000150) occurring during sea-level lowstands, which were characterized by relatively arid conditions in the Mediterranean. However, in a few cases, the greatest 87Sr/86Sr departures (up to 0.000300) occur during sea-level highstands, which are marked by more humid conditions. Because the correlations between peaks in Sr departures and highstands (humid conditions) occur only after episodes of prolonged aridity, variations of residence time of continental water (particularly groundwater) could have affected its Sr concentration, and hence the degree to which continental water could perturb 87Sr/86Sr in marine sub-basins. Although our results demonstrate that the forcing behind variations in Sr isotope composition in marginal marine basins is more complex than what is typically included in Sr isotope box models, they also imply that high-resolution records, particularly when combined with independent information on sea-level or climate changes, could offer unique insights into local tectonic, climatic, and sea-level variations.

Natural and human-induced driving factors in the evolution of tidal channels: case studies in the Venice Lagoon (Italy).

NASA Astrophysics Data System (ADS)

Rizzetto, Federica

2013-04-01

Coastal wetlands are largely affected by a complex variety of both natural and anthropogenic factors, which induce evident, often irreversible, geomorphological transformations. In particular, this research focuses on the main processes that influence the evolution of tidal channels in salt marshes and shows the results derived from the analysis of some case studies in the Venice Lagoon (northwestern Adriatic Sea, Italy). Here tidal network has been recognized as significantly sensitive to sea-level rise and tide oscillations (Rizzetto and Tosi, 2011; Rizzetto and Tosi, 2012), but it is also vulnerable to human impact. The sites were selected in areas characterized by low anthropogenic pressure to prevent strong human interferences from completely masking the effects of natural forces. The interpretation of a large number of high-resolution aerial photographs, taken since the mid 1930s, allowed identifying in detail tidal channel evolution, both in the long- and in the short-term. The observation of historical and recent topographic maps completed the study and provided other important data to define the modifications occurred in the past two centuries. The channel planform changes were determined through the morphometric analysis of the tidal network, carried out using a Geographic Information System software. These modifications were interpreted in the light of sea-level oscillations (i.e. relative sea-level rise and strength/frequency of high tides, which are increasing owing to climate changes), variations of sediment supply, and human activities occurred in the past century. The joint analysis of all the data allowed distinguishing the changes induced by both relative sea-level rise and high tides on planform pattern and evolution of tidal channels, and identifying the effects of human interferences, which magnified the impact of natural factors (e.g. groundwater exploitation responsible for high subsidence rates between 1950 and 1970 and, consequently, for an increase of relative sea-level rise in the same period) and/or produced other hydrodynamic, morphological, sedimentological modifications in the salt marshes, often resulting in erosion. References Rizzetto F., Tosi L., 2011. Aptitude of modern salt marshes to counteract relative sea-level rise, Venice Lagoon (Italy). Geology, 39 (8), 755-758. doi: 10.1130/G31736.1. Rizzetto F., Tosi L., 2012. Rapid response of tidal channel networks to sea-level variations (Venice Lagoon, Italy). Global and Planetary Change, 92-93, 191-197, doi: 10.1016/j.gloplacha.2012.05.022.

Assessing sea wave and spray effects on Marine Boundary Layer structure

NASA Astrophysics Data System (ADS)

Stathopoulos, Christos; Galanis, George; Patlakas, Platon; Kallos, George

2017-04-01

Air sea interface is characterized by several mechanical and thermodynamical processes. Heat, moisture and momentum exchanges increase the complexity in modeling the atmospheric-ocean system. Near surface atmospheric levels are subject to sea surface roughness and sea spray. Sea spray fluxes can affect atmospheric stability and induce microphysical processes such as sea salt particle formation and condensation/evaporation of water in the boundary layer. Moreover, presence of sea spray can alter stratification over the ocean surface with further insertion of water vapor. This can lead to modified stability conditions and to wind profiles that deviate significantly from the logarithmic approximation. To model these effects, we introduce a fully coupled system consisting of the mesoscale atmospheric model RAMS/ICLAMS and the wave model WAM. The system encompasses schemes for ocean surface roughness, sea salt aerosols and droplet thermodynamic processes and handles sea salt as predictive quantity. Numerical experiments using the developed atmospheric-ocean system are performed over the Atlantic and Mediterranean shoreline. Emphasis is given to the quantification of the improvement obtained in the description of the marine boundary layer, particularly in its lower part as well as in wave characteristics.

Elevated CO2 enhances biological contributions to elevation change in coastal wetlands by offsetting stressors associated with sea-level rise

USGS Publications Warehouse

Cherry, J.A.; McKee, K.L.; Grace, J.B.

2009-01-01

1. Sea-level rise, one indirect consequence of increasing atmospheric CO2, poses a major challenge to long-term stability of coastal wetlands. An important question is whether direct effects of elevated CO 2 on the capacity of marsh plants to accrete organic material and to maintain surface elevations outweigh indirect negative effects of stressors associated with sea-level rise (salinity and flooding). 2. In this study, we used a mesocosm approach to examine potential direct and indirect effects of atmospheric CO2 concentration, salinity and flooding on elevation change in a brackish marsh community dominated by a C3 species, Schoenoplectus americanus, and a C4 grass, Spartina patens. This experimental design permitted identification of mechanisms and their role in controlling elevation change, and the development of models that can be tested in the field. 3. To test hypotheses related to CO2 and sea-level rise, we used conventional anova procedures in conjunction with structural equation modelling (SEM). SEM explained 78% of the variability in elevation change and showed the direct, positive effect of S. americanus production on elevation. The SEM indicated that C3 plant response was influenced by interactive effects between CO2 and salinity on plant growth, not a direct CO2 fertilization effect. Elevated CO2 ameliorated negative effects of salinity on S. americanus and enhanced biomass contribution to elevation. 4. The positive relationship between S. americanus production and elevation change can be explained by shoot-base expansion under elevated CO 2 conditions, which led to vertical soil displacement. While the response of this species may differ under other environmental conditions, shoot-base expansion and the general contribution of C3 plant production to elevation change may be an important mechanism contributing to soil expansion and elevation gain in other coastal wetlands. 5. Synthesis. Our results revealed previously unrecognized interactions and mechanisms contributing to marsh elevation change, including amelioration of salt stress by elevated CO2 and the importance of plant production and shoot-base expansion for elevation gain. Identification of biological processes contributing to elevation change is an important first step in developing comprehensive models that permit more accurate predictions of whether coastal marshes will persist with continued sea-level rise or become submerged. ?? 2008 The Authors.

Effect of the New Insulation Liner on Noise Levels in the CH124B (Sea King) Aircraft

DTIC Science & Technology

2008-11-01

noise levels in the CH124B (Sea King) aircraft Bernadette Quémerais; DRDC Toronto TM 2008-182; R & D pour la défense Canada – Toronto; Novembre ... 13 vi DRDC Toronto TR 2008-182 List of figures Figure 1. Hoover, door closed, co...TR 2008-182 This page intentionally left blank. DRDC Toronto TR 2008-182 13 List of symbols/abbreviations/acronyms/initialisms

Glacial cycles drive variations in the production of oceanic crust

NASA Astrophysics Data System (ADS)

Crowley, J. W.; Katz, R. F.; Langmuir, C. H.; Huybers, P. J.

2013-12-01

Changes in sea level accompanying glacial cycles affect the static pressure within the asthenosphere; these variations could modulate melting rates beneath the mid-ocean ridge system as well as crustal thickness. These effects can be investigated and quantified using models of ridges based on conservation of mass, momentum, energy, and composition for two phases (magma & mantle) and two thermodynamic components (enriched & depleted). The models predict that the sensitivity of crustal thickness to oscillations in sea-level depends on the period of oscillation, the spreading rate of the ridge, and the assumed permeability scale of the melting regime. In contrast to previous studies (Huybers & Langmuir, 2009 and Lund & Asimow, 2011), the new results indicate that effects are larger for ridges with faster spreading rates. They also show that the dominant period of variations in crustal thickness changes with spreading rate and permeability. Sea-level variations with periods in the range of 10 ky - 100 ky can result in significant changes in crustal thickness that are orders of magnitude larger than the sea-level variations that drive them. Accurately modelling this process requires the inclusion of two previously unaccounted for processes: (1) determining the volume of the melting regime that is consistent with the ridge spreading rate and (2) properly treating the transport of melt. These enable us to capture the non-linear dependencies on spreading rate and other model parameters. Spectral analysis of bathymetry at two ridge segments that have a symmetric bathymetric signal and hence are undisturbed by off-axis volcanism or ridge jumps reveals the presence of variability at frequencies associated with precession, obliquity, and the 100 ky glacial/inter-glacial variability. Furthermore, the faster spreading ridge has larger amplitude responses to changes in sea level and shows a proportionately greater response at higher frequencies. These observations reinforce the possible links among climate cycles at the surface, mantle melting at depth and the crustal fabric of the sea floor.

Effects of Pleistocene sea-level fluctuations on mangrove population dynamics: a lesson from Sonneratia alba.

PubMed

Yang, Yuchen; Li, Jianfang; Yang, Shuhuan; Li, Xinnian; Fang, Lu; Zhong, Cairong; Duke, Norman C; Zhou, Renchao; Shi, Suhua

2017-01-18

A large-scale systematical investigation of the influence of Pleistocene climate oscillation on mangrove population dynamics could enrich our knowledge about the evolutionary history during times of historical climate change, which in turn may provide important information for their conservation. In this study, phylogeography of a mangrove tree Sonneratia alba was studied by sequencing three chloroplast fragments and seven nuclear genes. A low level of genetic diversity at the population level was detected across its range, especially at the range margins, which was mainly attributed to the steep sea-level drop and associated climate fluctuations during the Pleistocene glacial periods. Extremely small effective population size (Ne) was inferred in populations from both eastern and western Malay Peninsula (44 and 396, respectively), mirroring the fragility of mangrove plants and their paucity of robustness against future climate perturbations and human activity. Two major genetic lineages of high divergence were identified in the two mangrove biodiversity centres: the Indo-Malesia and Australasia regions. The estimated splitting time between these two lineages was 3.153 million year ago (MYA), suggesting a role for pre-Pleistocene events in shaping the major diversity patterns of mangrove species. Within the Indo-Malesia region, a subdivision was implicated between the South China Sea (SCS) and the remaining area with a divergence time of 1.874 MYA, corresponding to glacial vicariance when the emerged Sunda Shelf halted genetic exchange between the western and eastern coasts of the Malay Peninsula during Pleistocene sea-level drops. Notably, genetic admixture was observed in populations at the boundary regions, especially in the two populations near the Malacca Strait, indicating secondary contact between divergent lineages during interglacial periods. These interregional genetic exchanges provided ample opportunity for the re-use of standing genetic variation, which could facilitate mangrove establishment and adaptation in new habitats, especially in the context of global climate changes. Phylogeogrpahic analysis in this study reveal that Pleistocene sea-level fluctuations had profound influence on population differentiation of the mangrove tree S. alba. Our study highlights the fragility of mangrove plants and offers a guide for the conservation of coastal mangrove communities experiencing ongoing changes in sea-level.

Sea Level Rise, Rainfall and Coastal Flooding in Northeastern U.S. Cities Vivien Gornitz, Radley Horton, Philip Orton, Nickitas Georgas, Alan Blumberg, and Cynthia Rosenzweig

NASA Astrophysics Data System (ADS)

Gornitz, V.; Horton, R. M.; Orton, P. M.; Georgas, N.; Blumberg, A. F.; Rosenzweig, C.

2012-12-01

Populations and infrastructure along much of the northeastern coast of the United States will become increasingly vulnerable to the impacts of rising sea level and storm surges over the coming century. This vulnerability is amplified by regional land subsidence and likely also by shifts in ocean circulation. Building upon recent studies for the New York City Panel on Climate Change (NPCC), New York State ClimAid assessment, and the latest U.S. National Climate Assessment, we report new regional sea level rise projections based on the latest CMIP-5 global climate models (GCMs) and RCP emission scenarios, adjusted for revised glacial ice melt contributions, and other factors such as gravitational effects, land water storage, and changes in the Atlantic Meriodional Overturning Circulation (AMOC). Over the coming two years, GCM-derived sea level outputs for future decades will be utilized in risk assessments for coastal flooding in New York City, Boston, and Philadelphia, as part of the Consortium for Climate Risk in the Urban Northeast-RISA project. The Stevens Institute Estuarine and Coastal Ocean Model (sECOM) will be used to produce best estimates (including uncertainty ranges) of sea level rise impacts for a wide range of tropical and extra-tropical cyclones for the 2010s, 2050s, and 2080s. Major improvements over prior studies include (a) the use of a detailed, extensively validated ocean model, and (b) inclusion of rainfall and river flow influences on coastal flooding, which affect flood levels in enclosed tidal waterways (e.g., the Hudson and Delaware Rivers), and which are also likely important in coastal confluence zones of impermeable urbanized watersheds. In addition to the sea level rise results, we present initial model validation results for historical storms.

Sea-level change during the last 2500 years in New Jersey, USA

USGS Publications Warehouse

Kemp, Andrew C.; Horton, Benjamin P.; Vane, Christopher H.; Bernhardt, Christopher E.; Corbett, D. Reide; Engelhart, Simon E.; Anisfeld, Shimon C.; Parnell, Andrew C.; Cahill, Niamh

2013-01-01

Relative sea-level changes during the last ∼2500 years in New Jersey, USA were reconstructed to test if late Holocene sea level was stable or included persistent and distinctive phases of variability. Foraminifera and bulk-sediment δ13C values were combined to reconstruct paleomarsh elevation with decimeter precision from sequences of salt-marsh sediment at two sites using a multi-proxy approach. The additional paleoenvironmental information provided by bulk-sediment δ13C values reduced vertical uncertainty in the sea-level reconstruction by about one third of that estimated from foraminifera alone using a transfer function. The history of sediment deposition was constrained by a composite chronology. An age–depth model developed for each core enabled reconstruction of sea level with multi-decadal resolution. Following correction for land-level change (1.4 mm/yr), four successive and sustained (multi-centennial) sea-level trends were objectively identified and quantified (95% confidence interval) using error-in-variables change point analysis to account for age and sea-level uncertainties. From at least 500 BC to 250 AD, sea-level fell at 0.11 mm/yr. The second period saw sea-level rise at 0.62 mm/yr from 250 AD to 733 AD. Between 733 AD and 1850 AD, sea level fell at 0.12 mm/yr. The reconstructed rate of sea-level rise since ∼1850 AD was 3.1 mm/yr and represents the most rapid period of change for at least 2500 years. This trend began between 1830 AD and 1873 AD. Since this change point, reconstructed sea-level rise is in agreement with regional tide-gauge records and exceeds the global average estimate for the 20th century. These positive and negative departures from background rates demonstrate that the late Holocene sea level was not stable in New Jersey.

Recent Changes in High-Latitude Glaciers, Ice Caps, and Ice Sheets

NASA Technical Reports Server (NTRS)

Abdalati, Waleed

2006-01-01

The glaciers and ice sheets of the world contain enough ice to raise sea level by approximately 70 meters if they were to disappear entirely, and most of this ice is located in the climatically sensitive polar regions. Fortunately changes of this magnitude would probably take many thousands of years to occur, but recent discoveries indicate that these ice masses are responding to changes in today s climate more rapidly than previously thought. These responses are likely to be of great societal significance, primarily in terms of their implications for sea level, but also in terms of how their discharge of freshwater, through melting or calving, may impact ocean circulation. For millions of years, oceans have risen and fallen as the Earth has warmed and cooled, and ice on land has shrunk and grown. Today is no different in that respect, as sea levels have been rising at a rate of nearly 2 m per year during the last century (Miller and Douglas 2004), and 3 mm/yr in the last 12 years (Leuliette et al. 2004). What is different today, however, is that tens - perhaps hundreds - of millions of people live in coastal areas that are vulnerable to changes in sea level. Rising seas erode beaches, increase flood potential, and reduce the ability of barrier islands and coastal wetlands to mitigate the effects of major storms and hurricanes. The costs associated with a one-meter rise in sea level are estimated to be in the hundreds of billions of dollars in the United States alone. The worldwide costs in human terms would be far greater as some vulnerable low-lying coastal regions would become inundated, especially in poorer nations that do not have the resources to deal with such changes. Such considerations are particularly important in light of the fact that a one meter sea level rise is not significantly outside the 0.09 to 0.88 range of predictions for this century (IPCC 2001), and rises of this magnitude have occurred in the past in as little as 20 years (Fairbanks 1989). While the expansion of the warming oceans is estimated to be about a third of recent sea level rise, (Miller and Douglas 2004) the greatest potential for significantly increasing sea level lies in the Greenland and Antarctic ice sheets. For different reasons, each exhibits characteristics that suggest they are potentially unstable. In Antarctica, large portions of the ice cover rest on a soft bed that lies below sea level, making it vulnerable to runaway retreat. The Greenland ice sheet experiences considerable melt, which has the potential to rapidly accelerate the flow of ice toward the sea. While smaller ice masses, such as the Alaskan Glaciers and the Canadian ice caps, do not have anywhere near the same potential to impact sea level as the vast ice sheets do, many are melting rapidly, posing a significant near-term threat.

Forecasting the impact of storm waves and sea-level rise on Midway Atoll and Laysan Island within the Papahānaumokuākea Marine National Monument—a comparison of passive versus dynamic inundation models

USGS Publications Warehouse

Storlazzi, Curt D.; Berkowitz, Paul; Reynolds, Michelle H.; Logan, Joshua B.

2013-01-01

Two inundation events in 2011 underscored the potential for elevated water levels to damage infrastructure and affect terrestrial ecosystems on the low-lying Northwestern Hawaiian Islands in the Papahānaumokuākea Marine National Monument. The goal of this study was to compare passive "bathtub" inundation models based on geographic information systems (GIS) to those that include dynamic water levels caused by wave-induced set-up and run-up for two end-member island morphologies: Midway, a classic atoll with islands on the shallow (2-8 m) atoll rim and a deep, central lagoon; and Laysan, which is characterized by a deep (20-30 m) atoll rim and an island at the center of the atoll. Vulnerability to elevated water levels was assessed using hindcast wind and wave data to drive coupled physics-based numerical wave, current, and water-level models for the atolls. The resulting model data were then used to compute run-up elevations using a parametric run-up equation under both present conditions and future sea-level-rise scenarios. In both geomorphologies, wave heights and wavelengths adjacent to the island shorelines increased more than three times and four times, respectively, with increasing values of sea-level rise, as more deep-water wave energy could propagate over the atoll rim and larger wind-driven waves could develop on the atoll. Although these increases in water depth resulted in decreased set-up along the islands’ shorelines, the larger wave heights and longer wavelengths due to sea-level rise increased the resulting wave-induced run-up. Run-up values were spatially heterogeneous and dependent on the direction of incident wave direction, bathymetry, and island configuration. Island inundation was modeled to increase substantially when wave-driven effects were included, suggesting that inundation and impacts to infrastructure and terrestrial habitats will occur at lower values of predicted sea-level rise, and thus sooner in the 21st century, than suggested by passive GIS-based "bathtub" inundation models. Lastly, observations and the modeling results suggest that classic atolls with islands on a shallow atoll rim are more susceptible to the combined effects of sea-level rise and wave-driven inundation than atolls characterized by a deep atoll rim.

Examining global extreme sea level variations on the coast from in-situ and remote observations

NASA Astrophysics Data System (ADS)

Menendez, Melisa; Benkler, Anna S.

2017-04-01

The estimation of extreme water level values on the coast is a requirement for a wide range of engineering and coastal management applications. In addition, climate variations of extreme sea levels on the coastal area result from a complex interacting of oceanic, atmospheric and terrestrial processes across a wide range of spatial and temporal scales. In this study, variations of extreme sea level return values are investigated from two available sources of information: in-situ tide-gauge records and satellite altimetry data. Long time series of sea level from tide-gauge records are the most valuable observations since they directly measure water level in a specific coastal location. They have however a number of sources of in-homogeneities that may affect the climate description of extremes when this data source is used. Among others, the presence of gaps, historical time in-homogeneities and jumps in the mean sea level signal are factors that can provide uncertainty in the characterization of the extreme sea level behaviour. Moreover, long records from tide-gauges are sparse and there are many coastal areas worldwide without in-situ available information. On the other hand, with the accumulating altimeter records of several satellite missions from the 1990s, approaching 25 recorded years at the time of writing, it is becoming possible the analysis of extreme sea level events from this data source. Aside the well-known issue of altimeter measurements very close to the coast (mainly due to corruption by land, wet troposphere path delay errors and local tide effects on the coastal area), there are other aspects that have to be considered when sea surface height values estimated from satellite are going to be used in a statistical extreme model, such as the use of a multi-mission product to get long observed periods and the selection of the maxima sample, since altimeter observations do not provide values uniform in time and space. Here, we have compared the extreme values of 'still water level' and 'non-tidal-residual' of in-situ records from the GESLA2 dataset (Woodworth et al. 2016) against the novel coastal altimetry datasets (Cipollini et al. 2016). Seasonal patterns, inter-annual variability and long-term trends are analyzed. Then, a time-dependent extreme model (Menendez et al. 2009) is applied to characterize extreme sea level return values and their variability on the coastal area around the world.

Plants mediate soil organic matter decomposition in response to sea level rise.

PubMed

Mueller, Peter; Jensen, Kai; Megonigal, James Patrick

2016-01-01

Tidal marshes have a large capacity for producing and storing organic matter, making their role in the global carbon budget disproportionate to land area. Most of the organic matter stored in these systems is in soils where it contributes 2-5 times more to surface accretion than an equal mass of minerals. Soil organic matter (SOM) sequestration is the primary process by which tidal marshes become perched high in the tidal frame, decreasing their vulnerability to accelerated relative sea level rise (RSLR). Plant growth responses to RSLR are well understood and represented in century-scale forecast models of soil surface elevation change. We understand far less about the response of SOM decomposition to accelerated RSLR. Here we quantified the effects of flooding depth and duration on SOM decomposition by exposing planted and unplanted field-based mesocosms to experimentally manipulated relative sea level over two consecutive growing seasons. SOM decomposition was quantified as CO2 efflux, with plant- and SOM-derived CO2 separated via δ(13) CO2 . Despite the dominant paradigm that decomposition rates are inversely related to flooding, SOM decomposition in the absence of plants was not sensitive to flooding depth and duration. The presence of plants had a dramatic effect on SOM decomposition, increasing SOM-derived CO2 flux by up to 267% and 125% (in 2012 and 2013, respectively) compared to unplanted controls in the two growing seasons. Furthermore, plant stimulation of SOM decomposition was strongly and positively related to plant biomass and in particular aboveground biomass. We conclude that SOM decomposition rates are not directly driven by relative sea level and its effect on oxygen diffusion through soil, but indirectly by plant responses to relative sea level. If this result applies more generally to tidal wetlands, it has important implications for models of SOM accumulation and surface elevation change in response to accelerated RSLR. © 2015 John Wiley & Sons Ltd.

Ecological effects of full and partial protection in the crowded Mediterranean Sea: a regional meta-analysis.

PubMed

Giakoumi, Sylvaine; Scianna, Claudia; Plass-Johnson, Jeremiah; Micheli, Fiorenza; Grorud-Colvert, Kirsten; Thiriet, Pierre; Claudet, Joachim; Di Carlo, Giuseppe; Di Franco, Antonio; Gaines, Steven D; García-Charton, José A; Lubchenco, Jane; Reimer, Jessica; Sala, Enric; Guidetti, Paolo

2017-08-21

Marine protected areas (MPAs) are a cornerstone of marine conservation. Globally, the number and coverage of MPAs are increasing, but MPA implementation lags in many human-dominated regions. In areas with intense competition for space and resources, evaluation of the effects of MPAs is crucial to inform decisions. In the human-dominated Mediterranean Sea, fully protected areas occupy only 0.04% of its surface. We evaluated the impacts of full and partial protection on biomass and density of fish assemblages, some commercially important fishes, and sea urchins in 24 Mediterranean MPAs. We explored the relationships between the level of protection and MPA size, age, and enforcement. Results revealed significant positive effects of protection for fisheries target species and negative effects for urchins as their predators benefited from protection. Full protection provided stronger effects than partial protection. Benefits of full protection for fish biomass were only correlated with the level of MPA enforcement; fish density was higher in older, better enforced, and -interestingly- smaller MPAs. Our finding that even small, well-enforced, fully protected areas can have significant ecological effects is encouraging for "crowded" marine environments. However, more data are needed to evaluate sufficient MPA sizes for protecting populations of species with varying mobility levels.

Potentiometric surface and water-level difference maps of selected confined aquifers in Southern Maryland and Maryland’s Eastern Shore, 1975-2015

USGS Publications Warehouse

Curtin, Stephen E.; Staley, Andrew W.; Andreasen, David C.

2016-01-01

Key Results This report presents potentiometric-surface maps of the Aquia and Magothy aquifers and the Upper Patapsco, Lower Patapsco, and Patuxent aquifer systems using water levels measured during September 2015. Water-level difference maps are also presented for these aquifers. The water-level differences in the Aquia aquifer are shown using groundwater-level data from 1982 and 2015, while the water-level differences are shown for the Magothy aquifer using data from 1975 and 2015. Water-level difference maps for both the Upper Patapsco and Lower Patapsco aquifer systems are shown using data from 1990 and 2015. The water-level differences in the Patuxent aquifer system are shown using groundwater-level data from 2007 and 2015. The potentiometric surface maps show water levels ranging from 53 feet above sea level to 164 feet below sea level in the Aquia aquifer, from 86 feet above sea level to 106 feet below sea level in the Magothy aquifer, from 115 feet above sea level to 115 feet below sea level in the Upper Patapsco aquifer system, from 106 feet above sea level to 194 feet below sea level in the Lower Patapsco aquifer system, and from 165 feet above sea level to 171 feet below sea level in the Patuxent aquifer system. Water levels have declined by as much as 116 feet in the Aquia aquifer since 1982, 99 feet in the Magothy aquifer since 1975, 66 and 83 feet in the Upper Patapsco and Lower Patapsco aquifer systems, respectively, since 1990, and 80 feet in the Patuxent aquifer system since 2007.

Control of the sea lamprey (Petromyzon marinus) in Lake Superior, 1953-70

USGS Publications Warehouse

Smith, Bernard R.; Tibbles, J. James; Johnson, B.G.H.

1974-01-01

Although sea lamprey control and heavy plantings of hatchery-reared stock had restored lake trout abundance to prelamprey levels in many areas by 1970, the trout had not yet become self-sustaining. Additional effort will be required to further reduce the effects of lamprey predation.

Sea-Level Projections from the SeaRISE Initiative

NASA Technical Reports Server (NTRS)

Nowicki, Sophie; Bindschadler, Robert

2011-01-01

SeaRISE (Sea-level Response to Ice Sheet Evolution) is a community organized modeling effort, whose goal is to inform the fifth IPCC of the potential sea-level contribution from the Greenland and Antarctic ice sheets in the 21st and 22nd century. SeaRISE seeks to determine the most likely ice sheet response to imposed climatic forcing by initializing an ensemble of models with common datasets and applying the same forcing to each model. Sensitivity experiments were designed to quantify the sea-level rise associated with a change in: 1) surface mass balance, 2) basal lubrication, and 3) ocean induced basal melt. The range of responses, resulting from the multi-model approach, is interpreted as a proxy of uncertainty in our sea-level projections. http://websrv.cs .umt.edu/isis/index.php/SeaRISE_Assessment.

GRACE Mass Flux Measurements of Inland and Marginal Seas from Mascons: Analysis and Validation

NASA Astrophysics Data System (ADS)

Loomis, B.; Luthcke, S. B.; Sabaka, T. J.

2015-12-01

The latest GRACE time-variable gravity mascon solution from the NASA Goddard Space Flight Center (GSFC) applies an optimized set of models and constraints towards the direct measurement of 1-arc-degree global mass flux parameters each month. Separate mascon spatial constraint regions have been defined for the largest inland and marginal seas: Mediterranean Sea, Black Sea, Caspian Sea, Red Sea, and Hudson Bay. The mascon estimation approach, when applied with well-designed constraints, minimizes signal leakage across regional boundaries and eliminates the need for post-processing strategies. These post-processing techniques (e.g. smoothed averaging kernels) are necessary for computing regional mass change from the unconstrained spherical harmonics provided by the GRACE project to reduce the effect of noisy high degree and order terms, but introduce signal leakage into and out of the considered region. These mass signals are also difficult to obtain from altimetry measurements due to the comparatively sparse temperature and salinity data in these regions, which is needed to compute and remove the steric component of sea level variations. We provide new GSFC mascon measurements of these inland and marginal seas and compare to results obtained from kernel-averaged spherical harmonic solutions and steric-corrected altimetry measurements. The relative accuracy of the various solutions is determined by incorporating their output into the set of forward models applied in our processing of the GRACE Level-1B data and analyzing the effect on the inter-satellite range-rate residuals, where a reduction in residuals is a direct validation of improved solution quality.

Searching for Eustasy in Pliocene Sea-Level Records (Invited)

NASA Astrophysics Data System (ADS)

Raymo, M. E.; Hearty, P. J.; O'Leary, M.; Mitrovica, J.; Deconto, R.; Inglis, J. D.; Robinson, M. M.

2010-12-01

It is widely accepted that greenhouse gas-induced warming over the next few decades to centuries could lead to a rise in sea level due to melting ice caps. Yet despite the enormous social and economic consequences for society, our ability to predict the likelihood and location of future melting is hampered by an insufficient theoretical and historical understanding of ice sheet behavior in the past. Various lines of evidence suggest that CO2 levels in the mid-Pliocene were between 350-450 ppm, similar to today, and it is important that significant effort be made to confirm these estimates, especially in light of policy discussions that seek to determine a “safe” level of atmospheric CO2. Likewise, accurate estimates of mid-Pliocene sea levels are necessary if we are to better constrain Greenland and Antarctic ice sheet stability in a slightly warmer world. Current published estimates of mid-Pliocene sea level (during times of maximum insolation forcing) range from +5m to >+40m (relative to present) reflecting a huge range of uncertainty in the sensitivity of polar ice sheets, including the East Antarctic Ice Sheet, to a modest global warming. Accurate determination of the maximum mid-Pliocene sea level rise is needed if climate and ice sheet modelers are to better assess the robustness of models used to predict the effects of anthropogenic global warming. Pliocene ice volume/highstand estimates fall into two classes, those derived from geologic evidence of past high stands and those derived from geochemical proxies of ice-sensitive changes in ocean chemistry. Both methods have significant errors and uncertainties associated with them. Recent multidisciplinary work along the intra-plate continental margin of Roe Plain (~250 x 30 km) on the southern coastline of Western Australia provides additional constraints on sea level during the mid-Pliocene. Outcroppings of shore-proximal marine deposits are observed at two distinct elevations across the plain, +28 ± 2 m and +18 ± 2 m. Definitive sedimentary intertidal indications (e.g., concentrated concave down bivalves characteristic of a swash zone) and subtidal biofacies including articulated valves are found throughout the deposits and suggest the occurrence two distinct highstand events. Preliminary Sr-isotopes yield a broad range of mid to late Pliocene ages. These data will be discussed in light of possible ice volume, dynamic topography, and isostatic effects. Building on these data we present a strategy for improving the accuracy of mid Pliocene sea level estimates.

Effects of Climate Change on Exposure to Coastal Flooding in Latin America and the Caribbean

PubMed Central

Reguero, Borja G.; Losada, Iñigo J.; Díaz-Simal, Pedro; Méndez, Fernando J.; Beck, Michael W.

2015-01-01

This study considers and compares several of the most important factors contributing to coastal flooding in Latin American and the Caribbean (LAC) while accounting for the variations of these factors with location and time. The study assesses the populations, the land areas and the built capital exposed at present and at the middle and end of the 21st century for a set of scenarios that include both climatic and non-climatic drivers. Climatic drivers include global mean sea level, natural modes of climate variability such as El Niño, natural subsidence, and extreme sea levels resulting from the combination of projected local sea-level rise, storm surges and wave setup. Population is the only human-related driver accounted for in the future. Without adaptation, more than 4 million inhabitants will be exposed to flooding from relative sea-level rise by the end of the century, assuming the 8.5 W m−2 trajectory of the Representative Concentration Pathways (RCPs), or RCP8.5. However, the contributions from El Niño events substantially raise the threat in several Pacific-coast countries of the region and sooner than previously anticipated. At the tropical Pacific coastlines, the exposure by the mid-century for an event similar to El Niño 1998 would be comparable to that of the RCP4.5 relative sea-level rise by the end of the century. Furthermore, more than 7.5 million inhabitants, 42,600 km2 and built capital valued at 334 billion USD are currently situated at elevations below the 100-year extreme sea level. With sea levels rising and the population increasing, it is estimated that more than 9 million inhabitants will be exposed by the end of the century for either of the RCPs considered. The spatial distribution of exposure and the comparison of scenarios and timeframes can serve as a guide in future adaptation and risk reduction policies in the region. PMID:26177285

Spring fasting behavior in a marine apex predator provides an index of ecosystem productivity

USGS Publications Warehouse

Rode, Karyn D.; Wilson, Ryan R.; Douglas, David C.; Muhlenbruch, Vanessa L; Atwood, Todd C.; Regehr, Eric V.; Richardson, Evan; Pilfold, Nicholas; Derocher, Andrew E.; Durner, George M.; Stirling, Ian; Amstrup, Steven C.; St Martin, Michelle; Pagano, Anthony M.; Simac, Kristin

2018-01-01

The effects of declining Arctic sea ice on local ecosystem productivity are not well understood but have been shown to vary inter-specifically, spatially, and temporally. Because marine mammals occupy upper trophic levels in Arctic food webs, they may be useful indicators for understanding variation in ecosystem productivity. Polar bears (Ursus maritimus) are apex predators that primarily consume benthic and pelagic-feeding ice-associated seals. As such, their productivity integrates sea ice conditions and the ecosystem supporting them. Declining sea ice availability has been linked to negative population effects for polar bears but does not fully explain observed population changes. We examined relationships between spring foraging success of polar bears and sea ice conditions, prey productivity, and general patterns of ecosystem productivity in the Beaufort and Chukchi Seas (CSs). Fasting status (≥7 days) was estimated using serum urea and creatinine levels of 1,448 samples collected from 1,177 adult and subadult bears across three subpopulations. Fasting increased in the Beaufort Sea between 1983–1999 and 2000–2016 and was related to an index of ringed seal body condition. This change was concurrent with declines in body condition of polar bears and observed changes in the diet, condition and/or reproduction of four other vertebrate consumers within the food chain. In contrast, fasting declined in CS polar bears between periods and was less common than in the two Beaufort Sea subpopulations consistent with studies demonstrating higher primary productivity and maintenance or improved body condition in polar bears, ringed seals, and bearded seals despite recent sea ice loss in this region. Consistency between regional and temporal variation in spring polar bear fasting and food web productivity suggests that polar bears may be a useful indicator species. Furthermore, our results suggest that spatial and temporal ecological variation is important in affecting upper trophic-level productivity in these marine ecosystems.

Spring fasting behavior in a marine apex predator provides an index of ecosystem productivity.

PubMed

Rode, Karyn D; Wilson, Ryan R; Douglas, David C; Muhlenbruch, Vanessa; Atwood, Todd C; Regehr, Eric V; Richardson, Evan S; Pilfold, Nicholas W; Derocher, Andrew E; Durner, George M; Stirling, Ian; Amstrup, Steven C; St Martin, Michelle; Pagano, Anthony M; Simac, Kristin

2018-01-01

The effects of declining Arctic sea ice on local ecosystem productivity are not well understood but have been shown to vary inter-specifically, spatially, and temporally. Because marine mammals occupy upper trophic levels in Arctic food webs, they may be useful indicators for understanding variation in ecosystem productivity. Polar bears (Ursus maritimus) are apex predators that primarily consume benthic and pelagic-feeding ice-associated seals. As such, their productivity integrates sea ice conditions and the ecosystem supporting them. Declining sea ice availability has been linked to negative population effects for polar bears but does not fully explain observed population changes. We examined relationships between spring foraging success of polar bears and sea ice conditions, prey productivity, and general patterns of ecosystem productivity in the Beaufort and Chukchi Seas (CSs). Fasting status (≥7 days) was estimated using serum urea and creatinine levels of 1,448 samples collected from 1,177 adult and subadult bears across three subpopulations. Fasting increased in the Beaufort Sea between 1983-1999 and 2000-2016 and was related to an index of ringed seal body condition. This change was concurrent with declines in body condition of polar bears and observed changes in the diet, condition and/or reproduction of four other vertebrate consumers within the food chain. In contrast, fasting declined in CS polar bears between periods and was less common than in the two Beaufort Sea subpopulations consistent with studies demonstrating higher primary productivity and maintenance or improved body condition in polar bears, ringed seals, and bearded seals despite recent sea ice loss in this region. Consistency between regional and temporal variation in spring polar bear fasting and food web productivity suggests that polar bears may be a useful indicator species. Furthermore, our results suggest that spatial and temporal ecological variation is important in affecting upper trophic-level productivity in these marine ecosystems. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

An Ongoing Shift in Pacific Ocean Sea Level

NASA Astrophysics Data System (ADS)

Cheon, S. H.; Hamlington, B.; Thompson, P. R.; Merrifield, M. A.; Nerem, R. S.; Leben, R. R.; Kim, K. Y.

2016-12-01

According to the satellite altimeter data, local sea level trends have shown considerable diversity spatially as well as temporally. In particular, dramatic changes in sea level in the Pacific have been observed throughout the altimeter record, with high trends in the western tropical Pacific (WTP) and comparatively lower trends in the eastern Pacific. In recent years, however, a shift appears to be occurring, with falling trends in the (WTP) and rising trends in the eastern tropical and northeastern Pacific (ETP and NEP). From a planning perspective, it is important to figure out whether these sharp changes are part of a short-term shift or the beginning of a longer-term change in sea level. In this study, we distinguish the origins of the recent shift in Pacific Ocean sea level. Cyclostationary empirical orthogonal function (CSEOF) analysis is applied to separate the properties of the recent sea level change in the Pacific Ocean. From the CSEOF analysis results, we point out two dominant modes of sea level shift in the Pacific Ocean. The first mode is related to the biennial oscillation associated with El Nino-Southern Oscillation (ENSO) and the other is related to lower-frequency variability with a strong signal in the northern Pacific. Considering a relatively high correlation between recent sea level change and the low-frequency mode, we suggest that the low-frequency mode has played a dominant role in the sea level shift in the Pacific Ocean. Using a reconstructed sea level dataset, we examine the variability of this low-frequency mode in the past, and find similar periods of dramatic sea level change in the Pacific. Based on the sea level record of the last five years and according to the analysis, we conclude that in the coming decades, higher sea level trends off the U.S. West Coast should be expected, while reduced trends in the WTP will likely be observed.

A fractal analysis of quaternary, Cenozoic-Mesozoic, and Late Pennsylvanian sea level changes

NASA Technical Reports Server (NTRS)

Hsui, Albert T.; Rust, Kelly A.; Klein, George D.

1993-01-01

Sea level changes are related to both climatic variations and tectonic movements. The fractal dimensions of several sea level curves were compared to a modern climatic fractal dimension of 1.26 established for annual precipitation records. A similar fractal dimension (1.22) based on delta(O-18/O-16) in deep-sea sediments has been suggested to characterize climatic change during the past 2 m.y. Our analysis indicates that sea level changes over the past 150,000 to 250,000 years also exhibit comparable fractal dimensions. Sea level changes for periods longer than about 30 m.y. are found to produce fractal dimensions closer to unity and Missourian (Late Pennsylvanian) sea level changes yield a fractal dimension of 1.41. The fact that these sea level curves all possess fractal dimensions less than 1.5 indicates that sea level changes exhibit nonperiodic, long-run persistence. The different fractal dimensions calculated for the various time periods could be the result of a characteristic overprinting of the sediment recored by prevailing processes during deposition. For example, during the Quaternary, glacio-eustatic sea level changes correlate well with the present climatic signature. During the Missourian, however, mechanisms such as plate reorganization may have dominated, resulting in a significantly different fractal dimension.

Indo-Pacific sea level variability during recent decades

NASA Astrophysics Data System (ADS)

Yamanaka, G.; Tsujino, H.; Nakano, H.; Urakawa, S. L.; Sakamoto, K.

2016-12-01

Decadal variability of sea level in the Indo-Pacific region is investigated using a historical OGCM simulation. The OGCM driven by the atmospheric forcing removing long-term trends clearly exhibits decadal sea level variability in the Pacific Ocean, which is associated with eastern tropical Pacific thermal anomalies. During the period of 1977-1987, the sea level anomalies are positive in the eastern equatorial Pacific and show deviations from a north-south symmetric distribution, with strongly negative anomalies in the western tropical South Pacific. During the period of 1996-2006, in contrast, the sea level anomalies are negative in the eastern equatorial Pacific and show a nearly north-south symmetric pattern, with positive anomalies in both hemispheres. Concurrently, sea level anomalies in the south-eastern Indian Ocean vary with those in the western tropical Pacific. These sea level variations are closely related to large-scale wind fields. Indo-Pacific sea level distributions are basically determined by wind anomalies over the equatorial region as well as wind stress curl anomalies over the off-equatorial region.

Regional Sea Level Scenarios for Coastal Risk Management: Managing the Uncertainty of Future Sea Level Change and Extreme Water Levels for Department of Defense Coastal Sites Worldwide

DTIC Science & Technology

2016-04-01

SERDP NOAA USACE Ocean MANAGING THE UNCERTAINTY OF FUTURE SEA LEVEL CHANGE AND EXTREME WATER LEVELS FOR DEPARTMENT OF DEFENSE COASTAL SITES...WORLDWIDE APRIL 2016 REGIONAL SEA LEVEL SCENARIOS FOR COASTAL RISK MANAGEMENT: COVER PHOTOS, FROM LEFT TO RIGHT: - Overwash of the island of Roi-Namur on...J.A., S. Gill, J. Obeysekera, W. Sweet, K. Knuuti, and J. Marburger. 2016. Regional Sea Level Scenarios for Coastal Risk Management: Managing the

GGOS Focus Area 3: Understanding and Forecasting Sea-Level Rise and Variability

NASA Astrophysics Data System (ADS)

Schöne, Tilo; Shum, Ck; Tamisiea, Mark; Woodworth, Philip

2017-04-01

Sea level and its change have been measured for more than a century. Especially for coastal nations, deltaic regions, and coastal-oriented industries, observations of tides, tidal extremes, storm surges, and sea level rise at the interannual or longer scales have substantial impacts on coastal vulnerability towards resilience and sustainability of world's coastal regions. To date, the observed global sea level rise is largely associated with climate related changes. To find the patterns and fingerprints of those changes, and to e.g., separate the land motion from sea level signals, different monitoring techniques have been developed. Some of them are local, e.g., tide gauges, while others are global, e.g., satellite altimetry. It is well known that sea level change and land vertical motion varies regionally, and both signals need to be measured in order to quantify relative sea level at the local scale. The Global Geodetic Observing System (GGOS) and its services contribute in many ways to the monitoring of the sea level. These includes tide gauge observations, estimation of gravity changes, satellite altimetry, InSAR/Lidar, GNSS-control of tide gauges, providing ground truth sites for satellite altimetry, and importantly the maintenance of the International Reference Frame. Focus Area 3 (Understanding and Forecasting Sea-Level Rise and Variability) of GGOS establishes a platform and a forum for researchers and authorities dealing with estimating global and local sea level changes in a 10- to 30-year time span, and its project to the next century or beyond. It presents an excellent opportunity to emphasize the global, through to regional and local, importance of GGOS to a wide range of sea-level related science and practical applications. Focus Area 3 works trough demonstration projects to highlight the value of geodetic techniques to sea level science and applications. Contributions under a call for participation (http://www.ggos.org/Applications/theme3_SL.html) are welcome. The present status of GGOS Focus Area 3 will be highlighted. http://www.ggos-portal.org/lang_en/GGOS-Portal/EN/Themes/SeaLevel/seaLevel.html

Eustatic control of turbidites and winnowed turbidites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shanmugam, G.; Moiola, R.J.

1982-05-01

Global changes in sea level, primarily the results of tectonism and glaciation, control deep-sea sedimentation. During periods of low sea level the frequency of turbidity currents is greatly increased. Episodes of low sea level also cause vigorous contour currents, which winnow away the fines of turbidites. In the rock record, the occurrence of most turbidites and winnowed turbidities closely corresponds to global lowstands of paleo-sea level. This observation may be useful in predicting the occurrence of deep-sea reservoir facies in the geologic record.

Potentiometric Surface of the Lower Patapsco Aquifer in Southern Maryland, September 2007

USGS Publications Warehouse

Curtin, Stephen E.; Andreasen, David C.; Staley, Andrew W.

2009-01-01

This report presents a map showing the potentiometric surface of the lower Patapsco aquifer in the Patapsco Formation of Early Cretaceous age in Southern Maryland during September 2007. The map is based on water-level measurements in 65 wells. The highest measured water level was 111 feet above sea level near the northwestern boundary and outcrop area of the aquifer in northern Prince George's County. From this area, the potentiometric surface declined towards well fields at Severndale and Arnold. The measured ground-water levels were 87 feet below sea level at Severndale, and 42 feet below sea level at Arnold. There was also a cone of depression covering a large area in Charles County that includes Waldorf, La Plata, Indian Head, and the Morgantown power plant. The ground-water levels measured were as low as 219 feet below sea level at Waldorf, 187 feet below sea level at La Plata, 106 feet below sea level at Indian Head, and 89 feet below sea level at the Morgantown power plant.

Quantifying Population-Level Risks Using an Individual-Based Model: Sea Otters, Harlequin Ducks, and the Exxon Valdez Oil Spill

PubMed Central

Harwell, Mark A; Gentile, John H; Parker, Keith R

2012-01-01

Ecological risk assessments need to advance beyond evaluating risks to individuals that are largely based on toxicity studies conducted on a few species under laboratory conditions, to assessing population-level risks to the environment, including considerations of variability and uncertainty. Two individual-based models (IBMs), recently developed to assess current risks to sea otters and seaducks in Prince William Sound more than 2 decades after the Exxon Valdez oil spill (EVOS), are used to explore population-level risks. In each case, the models had previously shown that there were essentially no remaining risks to individuals from polycyclic aromatic hydrocarbons (PAHs) derived from the EVOS. New sensitivity analyses are reported here in which hypothetical environmental exposures to PAHs were heuristically increased until assimilated doses reached toxicity reference values (TRVs) derived at the no-observed-adverse-effects and lowest-observed-adverse-effects levels (NOAEL and LOAEL, respectively). For the sea otters, this was accomplished by artificially increasing the number of sea otter pits that would intersect remaining patches of subsurface oil residues by orders of magnitude over actual estimated rates. Similarly, in the seaduck assessment, the PAH concentrations in the constituents of diet, sediments, and seawater were increased in proportion to their relative contributions to the assimilated doses by orders of magnitude over measured environmental concentrations, to reach the NOAEL and LOAEL thresholds. The stochastic IBMs simulated millions of individuals. From these outputs, frequency distributions were derived of assimilated doses for populations of 500 000 sea otters or seaducks in each of 7 or 8 classes, respectively. Doses to several selected quantiles were analyzed, ranging from the 1-in-1000th most-exposed individuals (99.9% quantile) to the median-exposed individuals (50% quantile). The resulting families of quantile curves provide the basis for characterizing the environmental thresholds below which no population-level effects could be detected and above which population-level effects would be expected to become manifest. This approach provides risk managers an enhanced understanding of the risks to populations under various conditions and assumptions, whether under hypothetically increased exposure regimes, as demonstrated here, or in situations in which actual exposures are near toxic effects levels. This study shows that individual-based models are especially amenable and appropriate for conducting population-level risk assessments, and that they can readily be used to answer questions about the risks to individuals and populations across a variety of exposure conditions. Integr Environ Assess Manag 2012; 8: 503–522. © 2012 SETAC PMID:22275071

Quantifying population-level risks using an individual-based model: sea otters, Harlequin Ducks, and the Exxon Valdez oil spill.

PubMed

Harwell, Mark A; Gentile, John H; Parker, Keith R

2012-07-01

Ecological risk assessments need to advance beyond evaluating risks to individuals that are largely based on toxicity studies conducted on a few species under laboratory conditions, to assessing population-level risks to the environment, including considerations of variability and uncertainty. Two individual-based models (IBMs), recently developed to assess current risks to sea otters and seaducks in Prince William Sound more than 2 decades after the Exxon Valdez oil spill (EVOS), are used to explore population-level risks. In each case, the models had previously shown that there were essentially no remaining risks to individuals from polycyclic aromatic hydrocarbons (PAHs) derived from the EVOS. New sensitivity analyses are reported here in which hypothetical environmental exposures to PAHs were heuristically increased until assimilated doses reached toxicity reference values (TRVs) derived at the no-observed-adverse-effects and lowest-observed-adverse-effects levels (NOAEL and LOAEL, respectively). For the sea otters, this was accomplished by artificially increasing the number of sea otter pits that would intersect remaining patches of subsurface oil residues by orders of magnitude over actual estimated rates. Similarly, in the seaduck assessment, the PAH concentrations in the constituents of diet, sediments, and seawater were increased in proportion to their relative contributions to the assimilated doses by orders of magnitude over measured environmental concentrations, to reach the NOAEL and LOAEL thresholds. The stochastic IBMs simulated millions of individuals. From these outputs, frequency distributions were derived of assimilated doses for populations of 500,000 sea otters or seaducks in each of 7 or 8 classes, respectively. Doses to several selected quantiles were analyzed, ranging from the 1-in-1000th most-exposed individuals (99.9% quantile) to the median-exposed individuals (50% quantile). The resulting families of quantile curves provide the basis for characterizing the environmental thresholds below which no population-level effects could be detected and above which population-level effects would be expected to become manifest. This approach provides risk managers an enhanced understanding of the risks to populations under various conditions and assumptions, whether under hypothetically increased exposure regimes, as demonstrated here, or in situations in which actual exposures are near toxic effects levels. This study shows that individual-based models are especially amenable and appropriate for conducting population-level risk assessments, and that they can readily be used to answer questions about the risks to individuals and populations across a variety of exposure conditions. Copyright © 2012 SETAC.

Observed mean sea level changes around the North Sea coastline from 1800 to present

NASA Astrophysics Data System (ADS)

Wahl, T.; Haigh, I. D.; Woodworth, P. L.; Albrecht, F.; Dillingh, D.; Jensen, J.; Nicholls, R. J.; Weisse, R.; Wöppelmann, G.

2013-09-01

This paper assesses historic changes in mean sea level around the coastline of the North Sea, one of the most densely populated coasts in the world. Typically, such analyses have been conducted at a national level, and detailed geographically wider analyses have not been undertaken for about 20 years. We analyse long records (up to 200 years) from 30 tide gauge sites, which are reasonably uniformly distributed along the coastline, and: (1) calculate relative sea level trends; (2) examine the inter-annual and decadal variations; (3) estimate regional geocentric (sometimes also referred to as 'absolute') sea level rise throughout the 20th century; and (4) assess the evidence for regional acceleration of sea-level rise. Relative sea level changes are broadly consistent with known vertical land movement patterns. The inter-annual and decadal variability is partly coherent across the region, but with some differences between the Inner North Sea and the English Channel. Data sets from various sources are used to provide estimates of the geocentric sea level changes. The long-term geocentric mean sea level trend for the 1900 to 2011 period is estimated to be 1.5 ± 0.1 mm/yr for the entire North Sea region. The trend is slightly higher for the Inner North Sea (i.e. 1.6 ± 0.1 mm/yr), and smaller but not significantly different on the 95% confidence level for the English Channel (i.e. 1.2 ± 0.1 mm/yr). The uncertainties in the estimates of vertical land movement rates are still large, and the results from a broad range of approaches for determining these rates are not consistent. Periods of sea level rise acceleration are detected at different times throughout the last 200 years and are to some extent related to air pressure variations. The recent rates of sea level rise (i.e. over the last two to three decades) are high compared to the long-term average, but are comparable to those which have been observed at other times in the late 19th and 20th century.

Seasonal Sea-Level Variations in San Francisco Bay in Response to Atmospheric Forcing, 1980

USGS Publications Warehouse

Wang, Jingyuan; Cheng, R.T.; Smith, P.C.

1997-01-01

The seasonal response of sea level in San Francisco Bay (SFB) to atmospheric forcing during 1980 is investigated. The relations between sea-level data from the Northern Reach, Central Bay and South Bay, and forcing by local wind stresses, sea level pressure (SLP), runoff and the large scale sea level pressure field are examined in detail. The analyses show that the sea-level elevations and slopes respond to the along-shore wind stress T(V) at most times of the year, and to the cross-shore wind stress T(N) during two transition periods in spring and autumn. River runoff raises the sea-level elevation during winter. It is shown that winter precipitation in the SFB area is mainly attributed to the atmospheric circulation associated with the Alcutian Low, which transports the warm, moist air into the Bay area. A multiple linear regression model is employed to estimate the independent contributions of barometric pressure and wind stress to adjusted sea level. These calculations have a simple dynamical interpretation which confirms the importance of along-shore wind to both sea level and north-south slope within the Bay.

Coastal barrier stratigraphy for Holocene high-resolution sea-level reconstruction

PubMed Central

Costas, Susana; Ferreira, Óscar; Plomaritis, Theocharis A.; Leorri, Eduardo

2016-01-01

The uncertainties surrounding present and future sea-level rise have revived the debate around sea-level changes through the deglaciation and mid- to late Holocene, from which arises a need for high-quality reconstructions of regional sea level. Here, we explore the stratigraphy of a sandy barrier to identify the best sea-level indicators and provide a new sea-level reconstruction for the central Portuguese coast over the past 6.5 ka. The selected indicators represent morphological features extracted from coastal barrier stratigraphy, beach berm and dune-beach contact. These features were mapped from high-resolution ground penetrating radar images of the subsurface and transformed into sea-level indicators through comparison with modern analogs and a chronology based on optically stimulated luminescence ages. Our reconstructions document a continuous but slow sea-level rise after 6.5 ka with an accumulated change in elevation of about 2 m. In the context of SW Europe, our results show good agreement with previous studies, including the Tagus isostatic model, with minor discrepancies that demand further improvement of regional models. This work reinforces the potential of barrier indicators to accurately reconstruct high-resolution mid- to late Holocene sea-level changes through simple approaches. PMID:27929122

Separating decadal global water cycle variability from sea level rise.

PubMed

Hamlington, B D; Reager, J T; Lo, M-H; Karnauskas, K B; Leben, R R

2017-04-20

Under a warming climate, amplification of the water cycle and changes in precipitation patterns over land are expected to occur, subsequently impacting the terrestrial water balance. On global scales, such changes in terrestrial water storage (TWS) will be reflected in the water contained in the ocean and can manifest as global sea level variations. Naturally occurring climate-driven TWS variability can temporarily obscure the long-term trend in sea level rise, in addition to modulating the impacts of sea level rise through natural periodic undulation in regional and global sea level. The internal variability of the global water cycle, therefore, confounds both the detection and attribution of sea level rise. Here, we use a suite of observations to quantify and map the contribution of TWS variability to sea level variability on decadal timescales. In particular, we find that decadal sea level variability centered in the Pacific Ocean is closely tied to low frequency variability of TWS in key areas across the globe. The unambiguous identification and clean separation of this component of variability is the missing step in uncovering the anthropogenic trend in sea level and understanding the potential for low-frequency modulation of future TWS impacts including flooding and drought.

Coastal barrier stratigraphy for Holocene high-resolution sea-level reconstruction.

PubMed

Costas, Susana; Ferreira, Óscar; Plomaritis, Theocharis A; Leorri, Eduardo

2016-12-08

The uncertainties surrounding present and future sea-level rise have revived the debate around sea-level changes through the deglaciation and mid- to late Holocene, from which arises a need for high-quality reconstructions of regional sea level. Here, we explore the stratigraphy of a sandy barrier to identify the best sea-level indicators and provide a new sea-level reconstruction for the central Portuguese coast over the past 6.5 ka. The selected indicators represent morphological features extracted from coastal barrier stratigraphy, beach berm and dune-beach contact. These features were mapped from high-resolution ground penetrating radar images of the subsurface and transformed into sea-level indicators through comparison with modern analogs and a chronology based on optically stimulated luminescence ages. Our reconstructions document a continuous but slow sea-level rise after 6.5 ka with an accumulated change in elevation of about 2 m. In the context of SW Europe, our results show good agreement with previous studies, including the Tagus isostatic model, with minor discrepancies that demand further improvement of regional models. This work reinforces the potential of barrier indicators to accurately reconstruct high-resolution mid- to late Holocene sea-level changes through simple approaches.

An improved and homogeneous altimeter sea level record from the ESA Climate Change Initiative

NASA Astrophysics Data System (ADS)

Legeais, Jean-François; Ablain, Michaël; Zawadzki, Lionel; Zuo, Hao; Johannessen, Johnny A.; Scharffenberg, Martin G.; Fenoglio-Marc, Luciana; Joana Fernandes, M.; Baltazar Andersen, Ole; Rudenko, Sergei; Cipollini, Paolo; Quartly, Graham D.; Passaro, Marcello; Cazenave, Anny; Benveniste, Jérôme

2018-02-01

Sea level is a very sensitive index of climate change since it integrates the impacts of ocean warming and ice mass loss from glaciers and the ice sheets. Sea level has been listed as an essential climate variable (ECV) by the Global Climate Observing System (GCOS). During the past 25 years, the sea level ECV has been measured from space by different altimetry missions that have provided global and regional observations of sea level variations. As part of the Climate Change Initiative (CCI) program of the European Space Agency (ESA) (established in 2010), the Sea Level project (SL_cci) aimed to provide an accurate and homogeneous long-term satellite-based sea level record. At the end of the first phase of the project (2010-2013), an initial version (v1.1) of the sea level ECV was made available to users (Ablain et al., 2015). During the second phase of the project (2014-2017), improved altimeter standards were selected to produce new sea level products (called SL_cci v2.0) based on nine altimeter missions for the period 1993-2015 (https://doi.org/10.5270/esa-sea_level_cci-1993_2015-v_2.0-201612; Legeais and the ESA SL_cci team, 2016c). Corresponding orbit solutions, geophysical corrections and altimeter standards used in this v2.0 dataset are described in detail in Quartly et al. (2017). The present paper focuses on the description of the SL_cci v2.0 ECV and associated uncertainty and discusses how it has been validated. Various approaches have been used for the quality assessment such as internal validation, comparisons with sea level records from other groups and with in situ measurements, sea level budget closure analyses and comparisons with model outputs. Compared with the previous version of the sea level ECV, we show that use of improved geophysical corrections, careful bias reduction between missions and inclusion of new altimeter missions lead to improved sea level products with reduced uncertainties on different spatial and temporal scales. However, there is still room for improvement since the uncertainties remain larger than the GCOS requirements (GCOS, 2011). Perspectives on subsequent evolution are also discussed.

Intense sea-effect snowfall case on the western coast of Finland

NASA Astrophysics Data System (ADS)

Olsson, Taru; Perttula, Tuuli; Jylhä, Kirsti; Luomaranta, Anna

2017-07-01

A new national daily snowfall record was measured in Finland on 8 January 2016 when it snowed 73 cm (31 mm as liquid water) in less than a day in Merikarvia on the western coast of Finland. The area of the most intense snowfall was very small, which is common in convective precipitation. In this work we used hourly weather radar images to identify the sea-effect snowfall case and to qualitatively estimate the performance of HARMONIE, a non-hydrostatic convection-permitting weather prediction model, in simulating the spatial and temporal evolution of the snowbands. The model simulation, including data assimilation, was run at 2.5 km horizontal resolution and 65 levels in vertical. HARMONIE was found to capture the overall sea-effect snowfall situation quite well, as both the timing and the location of the most intense snowstorm were properly simulated. Based on our preliminary analysis, the snowband case was triggered by atmospheric instability above the mostly ice-free sea and a low-level convergence zone almost perpendicular to the coastline. The simulated convective available potential energy (CAPE) reached a value of 87 J kg-1 near the site of the observed snowfall record.

Cascading Effects of Ocean Acidification in a Rocky Subtidal Community

PubMed Central

Asnaghi, Valentina; Chiantore, Mariachiara; Mangialajo, Luisa; Gazeau, Frédéric; Francour, Patrice; Alliouane, Samir; Gattuso, Jean-Pierre

2013-01-01

Temperate marine rocky habitats may be alternatively characterized by well vegetated macroalgal assemblages or barren grounds, as a consequence of direct and indirect human impacts (e.g. overfishing) and grazing pressure by herbivorous organisms. In future scenarios of ocean acidification, calcifying organisms are expected to be less competitive: among these two key elements of the rocky subtidal food web, coralline algae and sea urchins. In order to highlight how the effects of increased pCO2 on individual calcifying species will be exacerbated by interactions with other trophic levels, we performed an experiment simultaneously testing ocean acidification effects on primary producers (calcifying and non-calcifying algae) and their grazers (sea urchins). Artificial communities, composed by juveniles of the sea urchin Paracentrotus lividus and calcifying (Corallina elongata) and non-calcifying (Cystoseira amentacea var stricta, Dictyota dichotoma) macroalgae, were subjected to pCO2 levels of 390, 550, 750 and 1000 µatm in the laboratory. Our study highlighted a direct pCO2 effect on coralline algae and on sea urchin defense from predation (test robustness). There was no direct effect on the non-calcifying macroalgae. More interestingly, we highlighted diet-mediated effects on test robustness and on the Aristotle's lantern size. In a future scenario of ocean acidification a decrease of sea urchins' density is expected, due to lower defense from predation, as a direct consequence of pH decrease, and to a reduced availability of calcifying macroalgae, important component of urchins' diet. The effects of ocean acidification may therefore be contrasting on well vegetated macroalgal assemblages and barren grounds: in the absence of other human impacts, a decrease of biodiversity can be predicted in vegetated macroalgal assemblages, whereas a lower density of sea urchin could help the recovery of shallow subtidal rocky areas affected by overfishing from barren grounds to assemblages dominated by fleshy macroalgae. PMID:23613994

Cascading effects of ocean acidification in a rocky subtidal community.

PubMed

Asnaghi, Valentina; Chiantore, Mariachiara; Mangialajo, Luisa; Gazeau, Frédéric; Francour, Patrice; Alliouane, Samir; Gattuso, Jean-Pierre

2013-01-01

Temperate marine rocky habitats may be alternatively characterized by well vegetated macroalgal assemblages or barren grounds, as a consequence of direct and indirect human impacts (e.g. overfishing) and grazing pressure by herbivorous organisms. In future scenarios of ocean acidification, calcifying organisms are expected to be less competitive: among these two key elements of the rocky subtidal food web, coralline algae and sea urchins. In order to highlight how the effects of increased pCO2 on individual calcifying species will be exacerbated by interactions with other trophic levels, we performed an experiment simultaneously testing ocean acidification effects on primary producers (calcifying and non-calcifying algae) and their grazers (sea urchins). Artificial communities, composed by juveniles of the sea urchin Paracentrotus lividus and calcifying (Corallina elongata) and non-calcifying (Cystoseira amentacea var stricta, Dictyota dichotoma) macroalgae, were subjected to pCO2 levels of 390, 550, 750 and 1000 µatm in the laboratory. Our study highlighted a direct pCO2 effect on coralline algae and on sea urchin defense from predation (test robustness). There was no direct effect on the non-calcifying macroalgae. More interestingly, we highlighted diet-mediated effects on test robustness and on the Aristotle's lantern size. In a future scenario of ocean acidification a decrease of sea urchins' density is expected, due to lower defense from predation, as a direct consequence of pH decrease, and to a reduced availability of calcifying macroalgae, important component of urchins' diet. The effects of ocean acidification may therefore be contrasting on well vegetated macroalgal assemblages and barren grounds: in the absence of other human impacts, a decrease of biodiversity can be predicted in vegetated macroalgal assemblages, whereas a lower density of sea urchin could help the recovery of shallow subtidal rocky areas affected by overfishing from barren grounds to assemblages dominated by fleshy macroalgae.

Contaminants still high in top-level carnivores in the Southern California Bight: levels of DDT and PCBs in resident and transient pinnipeds.

PubMed

Blasius, Mary Ellen; Goodmanlowe, Gwen D

2008-12-01

Highly industrialized areas, such as the Southern California Bight, often have high levels of contaminants in marine sediments, which can cause chronic exposure to organisms long after their use has ceased. tDDT and tPCB were analyzed in the blubber of 145 stranded pinnipeds that died at local marine mammal centers between 1994 and 2006. Resident species (California sea lion and Pacific harbor seal) had significantly higher concentrations of tDDT and tPCB than the transient species (northern elephant seal). Adult female California sea lions had significantly lower concentrations of tDDT and tPCB than pups, yearlings, and adult males. Concentrations of both tDDT and tPCB in California sea lions significantly declined over time, but did not change in northern elephant seals. Current concentrations of tDDT and tPCB in California sea lions and harbor seals are among the highest values reported worldwide for marine mammals and exceed those reported to cause adverse health effects.

Individual and molecular level effects of produced water contaminants on nauplii and adult females of Calanus finmarchicus.

PubMed

Jensen, Louise Kiel; Halvorsen, Elisabeth; Song, You; Hallanger, Ingeborg G; Hansen, Elisabeth Lindbo; Brooks, Steven J; Hansen, Bjørn Henrik; Tollefsen, Knut Erik

2016-01-01

In the Barents Sea region new petroleum fields are discovered yearly and extraction of petroleum products is expected to increase in the upcoming years. Despite enhanced technology and stricter governmental legislation, establishment of the petroleum industry in the Barents Sea may potentially introduce a new source of contamination to the area, as some discharges of produced water will be allowed. Whether the presence of produced water poses a risk to the Arctic marine life remains to be investigated. The aim of this study was to examine effects of exposure to several compounds found in produced water-a mixture of selected organic compounds (APW), radium-226 ((226)Ra), barium (Ba), and a scale inhibitor-on the copepod species Calanus finmarchicus. Experiments were performed using exposure concentrations at realistic levels based on those detected in the vicinity of known discharge points. The influence of lethal and sublethal effects on early life stages was determined and significantly lower survival in the APW exposure groups was found. In the Ba treatment the life stage development did not proceed to the same advanced stages as observed in the control (filtered sea water). The scale inhibitor and (226)Ra treatments showed no significant difference from control. In addition, adult females were exposed to APW, (226)Ra, and a mixture of the two. Both individual-level effects (egg production and feeding) and molecular-level effects (gene expression) were assessed. On the individual level endpoints, only treatments including APW produced an effect compared to control. However, on the molecular level the possibility that also (226)Ra induced toxicologically relevant effects cannot be ruled out.

Can human activities alter the drowning fate of barrier islands?

NASA Astrophysics Data System (ADS)

Lorenzo-Trueba, J.; Ashton, A. D.; Jin, D.; Hoagland, P.; Kite-Powell, H.

2012-12-01

Low-lying coastal barriers face an uncertain future over the coming century and beyond as sea levels rise, with many projections suggesting end-of-century rates of sea-level rise as high or higher than 1 cm/yr. Geologically, such rates of sea-level rise have been experienced several thousand years ago and we can use our understanding of geological processes and sedimentary evidence to help unravel the dynamics of natural barriers experiencing sea-level rise. Along many modern coastal barriers, however, anthropic change, such as beach nourishment, dune construction, and emplacement of hard structures, plays a dominant role in coastline dynamics. A fundamental question to be addressed is whether human activities intended to preserve infrastructure and beach recreation may make wholesale collapse, or 'drowning,' of barrier systems more likely. Here we present a numerical modeling tool that couples natural processes and the human responses to these changes (and the subsequent of human responses on natural processes). Recent theoretical model development suggests that barriers are intrinsically morphodynamic features, responding to sea-level rise in complex ways through the interactions of marine processes and barrier overwash. Undeveloped coastal barriers would therefore respond to an accelerated sea-level rise in complex, less predictable manners than suggested by existing long-term models. We have developed a model that examines non-equilibrium cross-shore evolution of barrier systems at decadal to centennial temporal scales, focusing on the interactions between processes of shoreface evolution and overwash deposition. Model responses demonstrate two means of barrier collapse during sea-level rise: 'height drowning', which occurs when overwash fluxes are insufficient to maintain the landward migration rate required to keep in pace with sea-level rise, and 'width drowning', which occurs when the shoreface response is insufficient to maintain the barrier geometry during landward migration. The model also demonstrates the potential for discontinuous shoreline retreat, with alternating periods of barrier stability and rapid migration, even for constant rates of sea-level rise. Anthropic activities can strongly interact with these behaviors. In particular, considering only cross-shore processes, beach nourishment activities widen the beach and can affect shoreface fluxes, and dune building, which curtails the overwash process, can potentially enhance barrier drowning by reducing overwash fluxes. Furthermore, coastal protection activities of adjacent communities or even individual property holders can be uncoordinated or coordinated, with their effects coupled along the coast through coastal reorientation and gradients in alongshore sediment transport. In the coordinated framework, owners act in concert to alter the barrier based upon community benefits, whereas in the non-coordinated framework owners alter only their own property. Another important role in management is the perception of future sea-level-rise-associated losses—communities manage their coast differently depending on their adopted forecast for sea-level rise. We find that coordinated behavior coupled with natural processes can substantially affect the drowning scenarios from the individual decision-making process.

Potentiometric Surface of the Lower Patapsco Aquifer in Southern Maryland, September 2009

USGS Publications Warehouse

Curtin, Stephen E.; Andreasin, David C.; Staley, Andrew W.

2010-01-01

This report presents a map showing the potentiometric surface of the lower Patapsco aquifer in the Patapsco Formation of Early Cretaceous age in Southern Maryland during September 2009. The map is based on water-level measurements in 64 wells. The highest measured water level was 110 feet above sea level near the northwestern boundary and outcrop area of the aquifer in northern Prince George's County. From this area, the potentiometric surface declined towards well fields at Severndale, Broad Creek, and Arnold. The measured groundwater levels were 99 feet below sea level at Severndale, 50 feet below sea level at Broad Creek, and 36 feet below sea level at Arnold. There was also a cone of depression in Charles County that includes Waldorf, La Plata, Indian Head, and the Morgantown power plant. The groundwater levels measured were as low as 215 feet below sea level at Waldorf, 149 feet below sea level at La Plata, 121 feet below sea level at Indian Head, and 96 feet below sea level at the Morgantown power plant. The map also shows well yield in gallons per day for 2008 at wells or well fields.

Sea level response to ENSO along the central California coast: How the 1997-1998 event compares with the historic record

USGS Publications Warehouse

Ryan, H.F.; Noble, M.

2002-01-01

Long-term monthly sea level and sea surface temperature (SST) anomalies from central California show that during winter months, positive anomalies are associated with El Nin??o events and the negative ones with La Nin??a events. There is no significant impact on monthly mean anomalies associated with Pacific decadal oscillations, although there is a tendency for more extreme events and greater variance during positive decadal oscillations. The very strong 1997-1998 El Nin??o was analyzed with respect to the long-term historic record to assess the forcing mechanisms for sea level and SST. Beginning in the spring of 1997, we observed several long-period (> 30days) fluctuations in daily sea level with amplitudes of over 10 cm at San Francisco, California. Fluctuations of poleward long-period alongshore wind stress anomalies (AWSA) are coherent with the sea level anomalies. However, the wind stress cannot entirely account for the observed sea level signals. The sea level fluctuations are also correlated with sea level fluctuations observed further south at Los Angeles and Tumaco, Columbia, which showed a poleward phase propagation of the sea level signal. We suggest that the sea level fluctuations were, to a greater degree, forced by the passage of remotely generated and coastally trapped waves that were generated along the equator and propagated to the north along the west coast of North America. However, both local and remote AWSA can significantly modulate the sea level signals. The arrival of coastally trapped waves began in the spring of 1997, which is earlier than previous strong El Nin??o events such as the 1982-1983 event. Published by Elsevier Science Ltd.

Brest sea level record: a time series construction back to the early eighteenth century

NASA Astrophysics Data System (ADS)

Wöppelmann, Guy; Pouvreau, Nicolas; Simon, Bernard

2006-12-01

The completeness and the accuracy of the Brest sea level time series dating from 1807 make it suitable for long-term sea level trend studies. New data sets were recently discovered in the form of handwritten tabulations, including several decades of the eighteenth century. Sea level observations have been made in Brest since 1679. This paper presents the historical data sets which have been assembled so far. These data sets span approximately 300 years and together constitute the longest, near-continuous set of sea level information in France. However, an important question arises: Can we relate the past and the present-day records? We partially provide an answer to this question by analysing the documents of several historical libraries with the tidal data using a ‘data archaeology’ approach advocated by Woodworth ( Geophys Res Lett 26:1589 1592, 1999b). A second question arises concerning the accuracy of such records. Careful editing was undertaken by examining the residuals between tidal predictions and observations. It proved useful to remove the worst effects of timing errors, in particular the sundial correction to be applied prior to August 1, 1714. A refined correction based on sundial literature [Savoie, La gnomique, Editions Les Belles Lettres, Paris, 2001] is proposed, which eliminates the systematic offsets seen in the discrepancies in timing of the sea level measurements. The tidal analysis has also shown that shallow-water tidal harmonics at Brest causes a systematic difference of 0.023 m between mean sea level (MSL) and mean tide level (MTL). Thus, MTL should not be mixed with the time series of MSL because of this systematic offset. The study of the trends in MTL and MSL however indicates that MTL can be used as a proxy for MSL. Three linear trend periods are distinguished in the Brest MTL time series over the period 1807 2004. Our results support the recent findings of Holgate and Woodworth ( Geophys Res Lett) of an enhanced coastal sea level rise during the last decade compared to the global estimations of about 1.8 mm/year over longer periods (Douglas, J Geophys Res 96:6981 6992, 1991). The onset of the relatively large global sea level trends observed in the twentieth century is an important question in the science of climate change. Our findings point out to an ‘inflexion point’ at around 1890, which is remarkably close to that in 1880 found in the Liverpool record by Woodworth ( Geophys Res Lett 26:1589 1592, 1999b).

Oxidative stress biomarkers and organochlorine pesticides in nesting female hawksbill turtles Eretmochelys imbricata from Mexican coast (Punta Xen, Mexico).

PubMed

Salvarani, Patricia I; Vieira, Luis R; Ku-Peralta, Wiliam; Morgado, Fernando; Osten, Jaime Rendón-von

2018-06-06

Because of their vulnerable population status, assessing exposure levels and impacts of toxicants on the health status of Gulf of Mexico marine turtle populations is essential, and this study was aimed to obtain baseline information on oxidative stress indicators in hawksbill sea turtle (Eretmochelys imbricata). In order to evaluate the health status of sea turtles and the effect of organochlorine compounds (OC) in the southern part of the Gulf of Mexico, we searched for relationships between carapace size and the activity of antioxidant enzymes in the blood of the hawksbill sea turtle. The level of oxidative stress biomarkers such as the enzymes catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GR), glutathione S-transferase (GST), and acetylcholinesterase (Ache) in the hawksbill sea turtle was analysed during nesting season in the years 2014-2015 at Punta Xen (Campeche, Mexico). The results of this study provide insight into data of antioxidant enzyme activities in relation to contaminant OCPs in hawksbill sea turtles and the possible health impacts of contaminant in sea turtles.

Coastal marsh response to historical and future sea-level acceleration

USGS Publications Warehouse

Kirwan, M.; Temmerman, S.

2009-01-01

We consider the response of marshland to accelerations in the rate of sea-level rise by utilizing two previously described numerical models of marsh elevation. In a model designed for the Scheldt Estuary (Belgium-SW Netherlands), a feedback between inundation depth and suspended sediment concentrations allows marshes to quickly adjust their elevation to a change in sea-level rise rate. In a model designed for the North Inlet Estuary (South Carolina), a feedback between inundation and vegetation growth allows similar adjustment. Although the models differ in their approach, we find that they predict surprisingly similar responses to sea-level change. Marsh elevations adjust to a step change in the rate of sea-level rise in about 100 years. In the case of a continuous acceleration in the rate of sea-level rise, modeled accretion rates lag behind sea-level rise rates by about 20 years, and never obtain equilibrium. Regardless of the style of acceleration, the models predict approximately 6-14 cm of marsh submergence in response to historical sea-level acceleration, and 3-4 cm of marsh submergence in response to a projected scenario of sea-level rise over the next century. While marshes already low in the tidal frame would be susceptible to these depth changes, our modeling results suggest that factors other than historical sea-level acceleration are more important for observations of degradation in most marshes today.

Linking micro- and macroevolutionary perspectives to evaluate the role of Quaternary sea-level oscillations in island diversification.

PubMed

Papadopoulou, Anna; Knowles, L Lacey

2017-12-01

With shifts in island area, isolation, and cycles of island fusion-fission, the role of Quaternary sea-level oscillations as drivers of diversification is complex and not well understood. Here, we conduct parallel comparisons of population and species divergence between two island areas of equivalent size that have been affected differently by sea-level oscillations, with the aim to understand the micro- and macroevolutionary dynamics associated with sea-level change. Using genome-wide datasets for a clade of seven Amphiacusta ground cricket species endemic to the Puerto Rico Bank (PRB), we found consistently deeper interspecific divergences and higher population differentiation across the unfragmented Western PRB, in comparison to the currently fragmented Eastern PRB that has experienced extreme changes in island area and connectivity during the Quaternary. We evaluate alternative hypotheses related to the microevolutionary processes (population splitting, extinction, and merging) that regulate the frequency of completed speciation across the PRB. Our results suggest that under certain combinations of archipelago characteristics and taxon traits, the repeated changes in island area and connectivity may create an opposite effect to the hypothesized "species pump" action of oscillating sea levels. Our study highlights how a microevolutionary perspective can complement current macroecological work on the Quaternary dynamics of island biodiversity. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

Sea-Level Rise and Land Subsidence in Deltas: Estimating Future Flood Risk Through Integrated Natural and Human System Modeling

NASA Astrophysics Data System (ADS)

Tessler, Z. D.; Vorosmarty, C. J.

2016-12-01

Deltas are highly sensitive to local human activities, land subsidence, regional water management, global sea-level rise, and climate extremes. We present a new delta flood exposure and risk framework for estimating the sensitivity of deltas to relative sea-level rise. We have applied this framework to a set of global environmental, geophysical, and social indicators over 48 major river deltas to quantify how contemporary risks vary across delta systems. The risk modeling framework incorporates upstream sediment flux and coastal land subsidence models, global empirical estimates of contemporary storm surge exposure, and population distribution and growth. Future scenarios are used to test the impacts on coastal flood risk of upstream dam construction, coastal population growth, accelerated sea-level rise, and enhanced storm surge. Results suggest a wide range of outcomes across different delta systems within each scenario. Deltas in highly engineered watersheds (Mississippi, Rhine) exhibit less sensitivity to increased dams due to saturation of sediment retention effects, though planned or under-construction dams are expected to have a substantial impact in the Yangtze, Irrawaddy, and Magdalena deltas. Population growth and sea-level rise are expected to be the dominant drivers of increased human risk in most deltas, with important exceptions in several countries, particularly China, where population are forecast to contract over the next several decades.

The response of Antarctic sea ice algae to changes in pH and CO2.

PubMed

McMinn, Andrew; Müller, Marius N; Martin, Andrew; Ryan, Ken G

2014-01-01

Ocean acidification substantially alters ocean carbon chemistry and hence pH but the effects on sea ice formation and the CO2 concentration in the enclosed brine channels are unknown. Microbial communities inhabiting sea ice ecosystems currently contribute 10-50% of the annual primary production of polar seas, supporting overwintering zooplankton species, especially Antarctic krill, and seeding spring phytoplankton blooms. Ocean acidification is occurring in all surface waters but the strongest effects will be experienced in polar ecosystems with significant effects on all trophic levels. Brine algae collected from McMurdo Sound (Antarctica) sea ice was incubated in situ under various carbonate chemistry conditions. The carbon chemistry was manipulated with acid, bicarbonate and bases to produce a pCO2 and pH range from 238 to 6066 µatm and 7.19 to 8.66, respectively. Elevated pCO2 positively affected the growth rate of the brine algal community, dominated by the unique ice dinoflagellate, Polarella glacialis. Growth rates were significantly reduced when pH dropped below 7.6. However, when the pH was held constant and the pCO2 increased, growth rates of the brine algae increased by more than 20% and showed no decline at pCO2 values more than five times current ambient levels. We suggest that projected increases in seawater pCO2, associated with OA, will not adversely impact brine algal communities.

Timescales for detecting a significant acceleration in sea level rise

PubMed Central

Haigh, Ivan D.; Wahl, Thomas; Rohling, Eelco J.; Price, René M.; Pattiaratchi, Charitha B.; Calafat, Francisco M.; Dangendorf, Sönke

2014-01-01

There is observational evidence that global sea level is rising and there is concern that the rate of rise will increase, significantly threatening coastal communities. However, considerable debate remains as to whether the rate of sea level rise is currently increasing and, if so, by how much. Here we provide new insights into sea level accelerations by applying the main methods that have been used previously to search for accelerations in historical data, to identify the timings (with uncertainties) at which accelerations might first be recognized in a statistically significant manner (if not apparent already) in sea level records that we have artificially extended to 2100. We find that the most important approach to earliest possible detection of a significant sea level acceleration lies in improved understanding (and subsequent removal) of interannual to multidecadal variability in sea level records. PMID:24728012

Reconciliation of late Quaternary sea levels derived from coral terraces at Huon Peninsula with deep sea oxygen isotope records

NASA Astrophysics Data System (ADS)

Chappell, John; Omura, Akio; Esat, Tezer; McCulloch, Malcolm; Pandolfi, John; Ota, Yoko; Pillans, Brad

1996-06-01

A major discrepancy between the Late Quaternary sea level changes derived from raised coral reef terraces at the Huon Peninsula in Papua New Guinea and from oxygen isotopes in deep sea cores is resolved. The two methods agree closely from 120 ka to 80 ka and from 20 ka to 0 ka (ka = 1000 yr before present), but between 70 and 30 ka the isotopic sea levels are 20-40 m lower than the Huon Peninsula sea levels derived in earlier studies. New, high precision U-series age measurements and revised stratigraphic data for Huon Peninsula terraces aged between 30 and 70 ka now give similar sea levels to those based on deep sea oxygen isotope data planktonic and benthic δ 18O data. Using the sea level and deep sea isotopic data, oxygen isotope ratios are calculated for the northern continental ice sheets through the last glacial cycle and are consistent with results from Greenland ice cores. The record of ice volume changes through the last glacial cycle now appears to be reasonably complete.

The global signature of post-1900 land ice wastage on vertical land motion

NASA Astrophysics Data System (ADS)

Riva, Riccardo; Frederikse, Thomas; King, Matt; Marzeion, Ben; van den Broeke, Michiel

2017-04-01

The amount of ice stored on land has strongly declined during the 20th century, and melt rates showed a significant acceleration over the last two decades. Land ice wastage is well known to be one of the main drivers of global mean sea-level rise, as widely discussed in the literature and reflected in the last assessment report of the IPCC. A less obvious effect of melting land ice is the response of the solid earth to mass redistribution on its surface, which, in the first approximation, results in land uplift where the load reduces (e.g., close to the meltwater sources) and land subsidence where the load increases (e.g., under the rising oceans). This effect is nowadays well known within the cryospheric and sea level communities. However, what is often not realized is that the solid earth response is a truly global effect: a localized mass change does cause a large deformation signal in its proximity, but also causes a change of the position of every other point on the Earth's surface. The theory of the Earth's elastic response to changing surface loads forms the basis of the 'sea-level equation', which allows sea-level fingerprints of continental mass change to be computed. In this paper, we provide the first dedicated analysis of global vertical land motion driven by land ice wastage. By means of established techniques to compute the solid earth elastic response to surface load changes and the most recent datasets of glacier and ice sheet mass change, we show that land ice loss currently leads to vertical deformation rates of several tenths of mm per year at mid-latitudes, especially over the Northern Hemisphere where most sources are located. In combination with the improved accuracy of space geodetic techniques (e.g., Global Navigation Satellite Systems), this means that the effect of ice melt is non-negligible over a large part of the continents. In particular, we show how deformation rates have been strongly varying through the last century, which implies that they should be properly modelled before interpreting and extrapolating recent observations of vertical land motion and sea level change.

Long term effect of a modified hydrodynamic at a lagoon inlet on the salt marsh ability to keep pace with sea level rise.

NASA Astrophysics Data System (ADS)

Carniello, L.; Nordio, G.; D'Alpaos, A.; Silvestri, S.

2016-12-01

In a context of global increase of mean sea level, the fate of salt marshes relates to their ability of keeping pace with relative sea level rise (SLR) and depends on the external sediment supply and organic soil production. Detecting the vertical sinking of salt marshes is a difficult task being the process characterized by time scales of tens to hundreds of years. Thanks to the availability of historical maps of the Venice lagoon, we reconstructed the reduction of salt mash areas that occurred in the northern part of the lagoon in the last two centuries. In this period, anthropic interventions played a crucial role in promoting the disappearance of vast marsh surfaces in the inner lagoon, while the marshes closer to the inlet remained fairly stable. Using a 2D numerical model we investigated the hydrodynamic behavior of different ancient lagoon configurations analyzing the effect of i) the construction of the jetties at the Lido inlet in 1882-1892 and ii) the removal of reed barriers that protected a fish farm area in the same period. Our results show that the deepening of the inlet induced by the construction of the jetties had a positive feedback on the vertical accretion of the salt marshes close to the inlet by lowering the local mean sea level and increasing the tidal amplitude. This effect contrasted the eustatic SLR for more than 30 years, allowing these marshes to increase their height with respect to the local mean sea level. On the contrary, the salt marshes far from the inlet could not take the same rapid advantage of this effect due to tidal wave dissipation characterizing tide propagation in shallow basins. Elevation of inner marshes is low due to the small tidal excursion, making these marshes extremely vulnerable to changes in sediment supply and SLR. We show that the removal of reed barriers used by ancient Venetians to create fish farms in the inner lagoon may have reduced the sediments available to the marshes thus contributing to their drowning.

Internet-based Modeling, Mapping, and Analysis for the Greater Everglades (IMMAGE; Version 1.0): web-based tools to assess the impact of sea level rise in south Florida

USGS Publications Warehouse

Hearn, Paul; Strong, David; Swain, Eric; Decker, Jeremy

2013-01-01

South Florida's Greater Everglades area is particularly vulnerable to sea level rise, due to its rich endowment of animal and plant species and its heavily populated urban areas along the coast. Rising sea levels are expected to have substantial impacts on inland flooding, the depth and extent of surge from coastal storms, the degradation of water supplies by saltwater intrusion, and the integrity of plant and animal habitats. Planners and managers responsible for mitigating these impacts require advanced tools to help them more effectively identify areas at risk. The U.S. Geological Survey's (USGS) Internet-based Modeling, Mapping, and Analysis for the Greater Everglades (IMMAGE) Web site has been developed to address these needs by providing more convenient access to projections from models that forecast the effects of sea level rise on surface water and groundwater, the extent of surge and resulting economic losses from coastal storms, and the distribution of habitats. IMMAGE not only provides an advanced geographic information system (GIS) interface to support decision making, but also includes topic-based modules that explain and illustrate key concepts for nontechnical users. The purpose of this report is to familiarize both technical and nontechnical users with the IMMAGE Web site and its various applications.

Health Impact Assessment Practice and Potential for Integration within Environmental Impact and Strategic Environmental Assessments in Italy

PubMed Central

Linzalone, Nunzia; Assennato, Giorgio; Ballarini, Adele; Cadum, Ennio; Cirillo, Mario; Cori, Liliana; De Maio, Francesca; Musmeci, Loredana; Natali, Marinella; Rieti, Sabrina; Soggiu, Maria Eleonora; Bianchi, Fabrizio

2014-01-01

Avoiding or minimizing potential environmental impact is the driving idea behind protecting a population’s health via Environmental Impact Assessments (EIAs) and Strategic Environmental Assessments (SEAs). However, both are often carried out without any systematic approach. This paper describes the findings of a review of HIA, EIA and SEA experiences carried out by the authors, who act as institutional competent subjects at the national and regional levels in Italy. The analysis of how health is tackled in EIA and SEA procedures could support the definition of a protocol for the integration of HIA with EIA and SEA. Although EIA and SEA approaches include the aim of protecting health, significant technical and methodological gaps are present when assessing health systematically, and their basic principles regarding assessment are unsatisfactory for promoting and addressing healthcare concepts stated by the WHO. HIA is still poorly integrated into the decision-making process, screening and monitoring phases are only occasionally implemented, and operational details are not well-defined. The collaborative approach of institutions involved in environment and health is a core element in a systematic advancement toward supporting effective decisions and effective protection of the environment and health. At the Italian national level, the definition of guidelines and tools for HIA, also in relation with EIA and SEA, is of great interest. PMID:25493391

Visioning the Future: Scenarios Modeling of the Florida Coastal Everglades

NASA Astrophysics Data System (ADS)

Flower, Hilary; Rains, Mark; Fitz, Carl

2017-11-01

In this paper, we provide screening-level analysis of plausible Everglades ecosystem response by 2060 to sea level rise (0.50 m) interacting with macroclimate change (1.5 °C warming, 7% increase in evapotranspiration, and rainfall that either increases or decreases by 10%). We used these climate scenarios as input to the Ecological Landscape Model to simulate changes to seven interactive hydro-ecological metrics. Mangrove forest and other marine influences migrated up to 15 km inland in both scenarios, delineated by the saltwater front. Freshwater habitat area decreased by 25-30% under our two climate change scenarios and was largely replaced by mangroves and, in the increased rainfall scenario, open water as well. Significant mangroves drowned along northern Florida Bay in both climate change scenarios due to sea level rise. Increased rainfall of 10% provided significant benefits to the spatial and temporal salinity regime within the marine-influenced zone, providing a more gradual and natural adjustment for at-risk flora and fauna. However, increased rainfall also increased the risk of open water, due to water depths that inhibited mangrove establishment and reduced peat accumulation rates. We infer that ecological effects related to sea level rise may occur in the extreme front-edge of saltwater intrusion, that topography will control the incursion of this zone as sea level rises, and that differences in freshwater availability will have ecologically significant effects on ecosystem resilience through the temporal and spatial pattern of salinity changes.

Visioning the Future: Scenarios Modeling of the Florida Coastal Everglades.

PubMed

Flower, Hilary; Rains, Mark; Fitz, Carl

2017-11-01

In this paper, we provide screening-level analysis of plausible Everglades ecosystem response by 2060 to sea level rise (0.50 m) interacting with macroclimate change (1.5 °C warming, 7% increase in evapotranspiration, and rainfall that either increases or decreases by 10%). We used these climate scenarios as input to the Ecological Landscape Model to simulate changes to seven interactive hydro-ecological metrics. Mangrove forest and other marine influences migrated up to 15 km inland in both scenarios, delineated by the saltwater front. Freshwater habitat area decreased by 25-30% under our two climate change scenarios and was largely replaced by mangroves and, in the increased rainfall scenario, open water as well. Significant mangroves drowned along northern Florida Bay in both climate change scenarios due to sea level rise. Increased rainfall of 10% provided significant benefits to the spatial and temporal salinity regime within the marine-influenced zone, providing a more gradual and natural adjustment for at-risk flora and fauna. However, increased rainfall also increased the risk of open water, due to water depths that inhibited mangrove establishment and reduced peat accumulation rates. We infer that ecological effects related to sea level rise may occur in the extreme front-edge of saltwater intrusion, that topography will control the incursion of this zone as sea level rises, and that differences in freshwater availability will have ecologically significant effects on ecosystem resilience through the temporal and spatial pattern of salinity changes.

Constraints on the thermosteric component of Last Interglacial sea level

NASA Astrophysics Data System (ADS)

Shackleton, S. A.; Severinghaus, J. P.; Petrenko, V. V.; Dyonisius, M.; Hmiel, B.

2016-12-01

With global temperatures 1 to 2°C above preindustrial, but sea level exceeding current levels by upwards of 8 meters, the Last Interglacial (LIG) period at 125 ka may provide valuable insight into Earth system constraints under future global warming. The relative contributions of thermal expansion and ice sheet loss to sea level rise over this period are of particular interest in seeking to improve sea level projections in the upcoming decades and beyond. Here we quantify this thermosteric component from a reconstruction of global ocean temperature over the LIG from atmospheric noble gases trapped in glacial ice. With no major sources or sinks outside of the ocean-atmosphere system, the relative changes in the atmospheric content of krypton, xenon, and nitrogen reflect changes in ocean gas storage. This storage is primarily governed by solubility and ocean temperature, making dKr/N2, dXe/N2­, and dXe/Kr unique tracers of globally integrated oceanic heat content. However, processes within the firn can fractionate these gases, and firn effects on these tracers must be removed to derive an ocean temperature. We present high precision measurements of these gas ratios along with isotopes of argon, krypton, and xenon in firn air withdrawn from the snowpack at Summit, Greenland. We use these isotopes to identify sources of fractionation within the firn and quantify their effects on the noble gas tracers, enabling a reconstruction of Last Interglacial ocean temperature.

Decadal sea level variability in the East China Sea linked to the North Pacific Gyre Oscillation

NASA Astrophysics Data System (ADS)

Moon, Jae-Hong; Song, Y. Tony

2017-07-01

In view of coastal community's need for adapting to sea level rise (SLR), understanding and predicting regional variability on decadal to longer time scales still remain a challenging issue in SLR research. Here, we have examined the low-frequency sea level signals in the East China Sea (ECS) from the 50-year hindcast of a non-Boussinesq ocean model in comparison with data sets from altimeters, tide-gauges, and steric sea level produced by in-situ profiles. It is shown that the mean sea levels in the ECS represent significant decadal fluctuations over the past 50 years, with a multi-decadal trend shift since the mid-1980s compared to the preceding 30 years. The decadal fluctuations in sea level are more closely linked to the North Pacific Gyre Oscillation (NPGO) rather than the Pacific Decadal Oscillation, which reflects the multi-decadal trend shift. A composite analysis indicates that wind patterns associated with the NPGO is shown to control the decadal variability of the western subtropical North Pacific. A positive NPGO corresponds to cyclonic wind stress curl anomaly in the western subtropical regions that results in a higher sea level in the ECS, particularly along the continental shelf, and lower sea levels off the ECS. The reverse occurs in years of negative NPGO.

Assessment of the impact of sea-level rise due to climate change on coastal groundwater discharge.

PubMed

Masciopinto, Costantino; Liso, Isabella Serena

2016-11-01

An assessment of sea intrusion into coastal aquifers as a consequence of local sea-level rise (LSLR) due to climate change was carried out at Murgia and Salento in southern Italy. The interpolation of sea-level measurements at three tide-gauge stations was performed during the period of 2000 to 2014. The best fit of measurements shows an increasing rate of LSLR ranging from 4.4mm/y to 8.8mm/y, which will result in a maximum LSLR of approximately 2m during the 22nd century. The local rate of sea-level rise matches recent 21st and 22nd century projections of mean global sea-level rise determined by other researchers, which include increased melting rates of the Greenland and Antarctic ice sheets, the effect of ocean thermal expansion, the melting of glaciers and ice caps, and changes in the quantity of stored land water. Subsequently, Ghyben-Herzberg's equation for the freshwater/saltwater interface was rewritten in order to determine the decrease in groundwater discharge due to the maximum LSLR. Groundwater flow simulations and ArcGIS elaborations of digital elevation models of the coast provided input data for the Ghyben-Herzberg calculation under the assumption of head-controlled systems. The progression of seawater intrusion due to LSLR suggests an impressive depletion of available groundwater discharge during the 22nd century, perhaps as much as 16.1% of current groundwater pumping for potable water in Salento. Copyright © 2016 Elsevier B.V. All rights reserved.

Anticipating Future Sea Level Rise and Coastal Storms in New York City (Invited)

NASA Astrophysics Data System (ADS)

Horton, R. M.; Gornitz, V.; Bader, D.; Little, C. M.; Oppenheimer, M.; Patrick, L.; Orton, P. M.; Rosenzweig, C.; Solecki, W.

2013-12-01

Hurricane Sandy caused 43 fatalities in New York City and 19 billion in damages. Mayor Michael Bloomberg responded by convening the second New York City Panel on Climate Change (NPCC2), to provide up-to-date climate information for the City's Special Initiative for Rebuilding and Resiliency (SIRR). The Mayor's proposed 20 billion plan aims to strengthen the City's resilience to coastal inundation. Accordingly, the NPCC2 scientific and technical support team generated a suite of temperature, precipitation, and sea level rise and extreme event projections through the 2050s. The NPCC2 sea level rise projections include contributions from ocean thermal expansion, dynamic changes in sea surface height, mass changes in glaciers, ice caps, and ice sheets, and land water storage. Local sea level changes induced by changes in ice mass include isostatic, gravitational, and rotational effects. Results are derived from CMIP5 model-based outputs, expert judgment, and literature surveys. Sea level at the Battery, lower Manhattan, is projected to rise by 7-31 in (17.8-78.7cm) by the 2050s relative to 2000-2004 (10 to 90 percentile). As a result, flood heights above NAVD88 for the 100-year storm (stillwater plus waves) would rise from 15.0 ft (0.71 m) in the 2000s to 15.6-17.6 ft (4.8-5.4 m) by the 2050s (10-90 percentile). The annual chance of today's 100-year flood would increase from 1 to 1.4-5.0 percent by the 2050s.

Effect of different simulated altitudes on repeat-sprint performance in team-sport athletes.

PubMed

Goods P, S R; Dawson, Brian T; Landers, Grant J; Gore, Christopher J; Peeling, Peter

2014-09-01

This study aimed to assess the impact of 3 heights of simulated altitude exposure on repeat-sprint performance in team-sport athletes. Ten trained male team-sport athletes completed 3 sets of repeated sprints (9 × 4 s) on a nonmotorized treadmill at sea level and at simulated altitudes of 2000, 3000, and 4000 m. Participants completed 4 trials in a random order over 4 wk, with mean power output (MPO), peak power output (PPO), blood lactate concentration (Bla), and oxygen saturation (SaO2) recorded after each set. Each increase in simulated altitude corresponded with a significant decrease in SaO2. Total work across all sets was highest at sea level and correspondingly lower at each successive altitude (P < .05; sea level < 2000 m < 3000 m < 4000 m). In the first set, MPO was reduced only at 4000 m, but for subsequent sets, decreases in MPO were observed at all altitudes (P < .05; 2000 m < 3000 m < 4000 m). PPO was maintained in all sets except for set 3 at 4000 m (P < .05; vs sea level and 2000 m). BLa levels were highest at 4000 m and significantly greater (P < .05) than at sea level after all sets. These results suggest that "higher may not be better," as a simulated altitude of 4000 m may potentially blunt absolute training quality. Therefore, it is recommended that a moderate simulated altitude (2000-3000 m) be employed when implementing intermittent hypoxic repeat-sprint training for team-sport athletes.

The effect of humidity on engine power at altitude

NASA Technical Reports Server (NTRS)

Brooks, D G; Garlock, E A

1933-01-01

From tests made in the altitude chamber of the Bureau of Standards, it was found that the effect of humidity on engine power is the same at altitudes up to 25,000 feet as at sea level. Earlier tests on automotive engines, made under sea-level conditions, showed that water vapor acts as an inert diluent, reducing engine power in proportion to the amount of vapor present. By combining the effects of atmospheric pressure, temperature, and humidity, it is shown that the indicated power obtainable from an engine is proportional to its mass rate of consumption of oxygen. This has led the National Advisory Committee for Aeronautics to adopt a standard basis for the correction of engine performance, in which the effect of humidity is included.

MIS 5e sea level: up to what point can we use literature reviews to answer the most pressing questions on the Last Interglacial ice sheets?

NASA Astrophysics Data System (ADS)

Rovere, A.; Raymo, M. E.

2014-12-01

During MIS 5e (between ~128 and 116 kyr BP) greenhouse gas concentrations were comparable to pre-industrial levels, summer insolation was higher by ~10% at high latitudes and polar temperatures in both hemispheres were about 3-5 °C warmer than today. Sea level (SL) at this time has been a subject of numerous studies (and some debate) with ~1000 sites with MIS 5e sea level markers recognized worldwide. Recently, Kopp et al. (Nature, 2009) and Dutton & Lambeck (Science, 2012) analyzed worldwide datasets of sea level markers pertaining to the last interglacial. After accounting for GIA, they reached similar conclusions that eustatic (i.e., globally averaged) sea level (ESL) was between +5 and +9.4 m above modern during MIS 5e. Furthermore, Kopp et al. (Nature, 2009; GJI, 2013) suggest that sea level was not uniform during the LIG, but instead underwent at least two rapid oscillations including a rapid late 5e rise first proposed by Hearty et al. (QSR, 2007) and later by O'Leary et al. (Nat. Geo., 2013). Investigating the temporal and geographic variability of MIS 5e sea level opens new lines of research, in particular the possibility to fingerprint (Hay et al., QSR, 2014) the source of the proposed rapid ice sheet collapse near the end of the Last Interglacial. In this presentation we ask: can we use a database of published sea level estimates for this purpose? To answer this question, we built a relative sea level (RSL) database using RSLcalc 2.0; this is a relational database specifically designed to review relative sea level data points while keeping all the relevant information contained in the original publications. RSlcalc allows to estimate the measurement error (on the actual elevation of the SL feature), the error on the indicative range (the elevation range occupied by a sea level indicator) as well as the reference water level (the relationship between the marker and the former sea level). We show that the majority of published data have an accuracy of few meters at best and, in most cases, are not precise enough for sea level fingerprinting. We conclude that the use of topographic-grade survey techniques is paramount in the study of paleo-sea levels and that revisiting known sites using such techniques is a priority for the understanding of polar ice volume and sea level changes during past interglacials

Coral mortality induced by the 2015-2016 El-Niño in Indonesia: the effect of rapid sea level fall

NASA Astrophysics Data System (ADS)

Elvan Ampou, Eghbert; Johan, Ofri; Menkes, Christophe E.; Niño, Fernando; Birol, Florence; Ouillon, Sylvain; Andréfouët, Serge

2017-02-01

The 2015-2016 El-Niño and related ocean warming has generated significant coral bleaching and mortality worldwide. In Indonesia, the first signs of bleaching were reported in April 2016. However, this El Niño has impacted Indonesian coral reefs since 2015 through a different process than temperature-induced bleaching. In September 2015, altimetry data show that sea level was at its lowest in the past 12 years, affecting corals living in the bathymetric range exposed to unusual emersion. In March 2016, Bunaken Island (North Sulawesi) displayed up to 85 % mortality on reef flats dominated by Porites, Heliopora and Goniastrea corals with differential mortality rates by coral genus. Almost all reef flats showed evidence of mortality, representing 30 % of Bunaken reefs. For reef flat communities which were living at a depth close to the pre-El Niño mean low sea level, the fall induced substantial mortality likely by higher daily aerial exposure, at least during low tide periods. Altimetry data were used to map sea level fall throughout Indonesia, suggesting that similar mortality could be widespread for shallow reef flat communities, which accounts for a vast percent of the total extent of coral reefs in Indonesia. The altimetry historical records also suggest that such an event was not unique in the past two decades, therefore rapid sea level fall could be more important in the dynamics and resilience of Indonesian reef flat communities than previously thought. The clear link between mortality and sea level fall also calls for a refinement of the hierarchy of El Niño impacts and their consequences on coral reefs.

Steric sea level variability (1993-2010) in an ensemble of ocean reanalyses and objective analyses

NASA Astrophysics Data System (ADS)

Storto, Andrea; Masina, Simona; Balmaseda, Magdalena; Guinehut, Stéphanie; Xue, Yan; Szekely, Tanguy; Fukumori, Ichiro; Forget, Gael; Chang, You-Soon; Good, Simon A.; Köhl, Armin; Vernieres, Guillaume; Ferry, Nicolas; Peterson, K. Andrew; Behringer, David; Ishii, Masayoshi; Masuda, Shuhei; Fujii, Yosuke; Toyoda, Takahiro; Yin, Yonghong; Valdivieso, Maria; Barnier, Bernard; Boyer, Tim; Lee, Tony; Gourrion, Jérome; Wang, Ou; Heimback, Patrick; Rosati, Anthony; Kovach, Robin; Hernandez, Fabrice; Martin, Matthew J.; Kamachi, Masafumi; Kuragano, Tsurane; Mogensen, Kristian; Alves, Oscar; Haines, Keith; Wang, Xiaochun

2017-08-01

Quantifying the effect of the seawater density changes on sea level variability is of crucial importance for climate change studies, as the sea level cumulative rise can be regarded as both an important climate change indicator and a possible danger for human activities in coastal areas. In this work, as part of the Ocean Reanalysis Intercomparison Project, the global and regional steric sea level changes are estimated and compared from an ensemble of 16 ocean reanalyses and 4 objective analyses. These estimates are initially compared with a satellite-derived (altimetry minus gravimetry) dataset for a short period (2003-2010). The ensemble mean exhibits a significant high correlation at both global and regional scale, and the ensemble of ocean reanalyses outperforms that of objective analyses, in particular in the Southern Ocean. The reanalysis ensemble mean thus represents a valuable tool for further analyses, although large uncertainties remain for the inter-annual trends. Within the extended intercomparison period that spans the altimetry era (1993-2010), we find that the ensemble of reanalyses and objective analyses are in good agreement, and both detect a trend of the global steric sea level of 1.0 and 1.1 ± 0.05 mm/year, respectively. However, the spread among the products of the halosteric component trend exceeds the mean trend itself, questioning the reliability of its estimate. This is related to the scarcity of salinity observations before the Argo era. Furthermore, the impact of deep ocean layers is non-negligible on the steric sea level variability (22 and 12 % for the layers below 700 and 1500 m of depth, respectively), although the small deep ocean trends are not significant with respect to the products spread.

Projections of tsunami inundation area coupled with impacts of sea level rise in Banda Aceh, Indonesia

NASA Astrophysics Data System (ADS)

Tursina, Syamsidik, Kato, Shigeru

2017-10-01

In a long term, sea level rise is anticipated to give devastating effects on Banda Aceh, as one of the coastal cities in the northern tip of Sumatra. The growth of the population and buildings in the city has come to the stage where the coastal area is vulnerable to any coastal hazard. Some public facilities and settlements have been constructed and keep expanding in the future. According to TOPEX/POSEIDON satellite images, 7 mm/year the sea level has been risen between 1992 and 2015 in this area. It is estimated that in the next 100 years, there will be 700 mm additional sea level rise which will give a setback more over to a rather flat area around the coast. This research is aim at investigating the influence of sea level rise toward the tsunami inundation on the land area particularly the impacts on Banda Aceh city. Cornell Multigrid Coupled Tsunami Model (COMCOT) simulation numerically generated tsunami propagation. Topography and bathymetry data were collected from GEBCO and updated with the available nautical chart (DISHIDROS, JICA, and field measurements). Geological movement of the underwater fault was generated using Piatanesi and Lorito of 9.15 Mw 2004 multi-fault scenario. The inundation area produced by COMCOT revealed that the inundation area was expanded to several hundred meters from the shoreline. To investigate the impacts of tsunami wave on Banda Aceh, the inundation area were digitized and analyzed with Quantum GIS spatial tools. The Quantum GIS analyzed inundations area affected by the projected tsunami. It will give a new tsunami-prone coastal area map induced by sea level rise in 100 years.

Assessment on vulnerability of coastal wetlands to sea level rise in the Yangtze Estuary, China

NASA Astrophysics Data System (ADS)

Cui, L.; Ge, Z.; Zhang, L.

2013-12-01

The Yangtze Delta in China is vital economic hubs in terms of settlement, industry, agriculture, trade and tourism as well as of great environmental significance. In recent decades, the prospect of climate change, in particular sea level rise and its effects on low lying coastal areas have generated worldwide attention to coastal ecosystems. Coastal wetlands, as important parts of coastal ecosystem, are particularly sensitive to sea level rise. To study the responses of coastal wetlands to climate change, assess the impacts of climate change on coastal wetlands and formulate feasible and practical mitigation strategies are the important prerequisites for securing the coastal zone ecosystems. In this study, taking the coastal wetlands in the Yangtze Estuary as a case study, the potential impacts of sea-level rise to coastal wetlands habitat were analyzed by the Source-Pathway-Receptor-Consequence (SPRC) model. The key indicators, such as the sea-level rise rate, subsidence rate, elevation, daily inundation duration of habitat and sedimentation rate, were selected to build a vulnerability assessment system according to the IPCC definition of vulnerability, i.e. the aspects of exposure, sensitivity and adaptation. A quantitatively spatial assessment method on the GIS platform was established by quantifying each indicator, calculating the vulnerability index and grading the vulnerability. The vulnerability assessment on the coastal wetlands in the Yangtze Estuary under the sea level rise rate of the present trend and IPCC A1F1 scenario were performed for three sets of projections of short-term (2030s), mid-term (2050s) and long-term (2100s). The results showed that at the present trend of sea level rise rate of 0.26 cm/a, 92.3 % of the coastal wetlands in the Yangtze Estuary was in the EVI score of 0 in 2030s, i.e. the impact of sea level rise on habitats/species of coastal wetlands was negligible. While 7.4 % and 0.3 % of the coastal wetlands were in the EVI score of 1(low vulnerability) and 2 (moderate vulnerability), respectively. In 2050s, 88.8 %, 10.7 % and 0.5 % of the coastal wetlands were in the EVI score of 0, 1 and 2, respectively. In 2100s, 85.7 %, 7.3 % , 2.0 % and 5.0 % of the coastal wetlands were in the EVI score of 0, 1, 2 and 3(high vulnerability), respectively. At the A1F1 scenario of sea level rise rate of 0.59 cm/a, 91.0 %, 8.7 % and 0.3 % of the coastal wetlands in 2030s were in the EVI score of 0, 1 and 2 , respectively. In 2050s, 86.9 %, 10.5 % , 2.4 % and 0.2 % of the coastal wetlands were in the EVI score of 0, 1, 2 and 3, respectively. In 2100s, 82.4 %, 7.1 % , 2.4 % and 8.1 % of the coastal wetlands were in the EVI score of 0, 1, 2 and 3, respectively. The spatiotemporal occurrences of vulnerability were mainly where the subsidence rate is relatively higher and the sedimentation rate is lower or even negative. The results from this study indicated that the combined effects of sea level rise, land subsidence, reducing sediment discharge could give rise to the high risk of a considerable decrease or even habitat loss of coastal wetland in the Yangtze Estuary (particularly in 2050s and 2100s). Therefore some mitigation measures should be considered in the future, including management of sedimentation, reducing land subsidence, recreating and extending wetland habitat, and controlling reclamation.

On the significance of incorporating shoreline changes for evaluating coastal hydrodynamics under sea level rise scenarios

NASA Astrophysics Data System (ADS)

Passeri, D.; Hagen, S. C.; Medeiros, S. C.

2013-12-01

Sea level rise (SLR) threatens coastal environments with loss of land, inundation of coastal wetlands, and increased flooding during extreme storm events. Research has shown that SLR is a major factor in the long-term, gradual retreat of shorelines (Fitzgerald et al., 2008). Along sandy shorelines, retreat has a more dynamic effect than just inundation due to rising water levels, including the physical process of erosion in which sand is removed from the shoreface and deposited offshore. This has the potential to affect ecological habitats as well as coastal communities. Although SLR induces seaward retreat of shorelines, many shorelines especially within the vicinity of inlets may experience accretion due to sediment trapping or beach replenishment (Aubrey and Giese, 1993, Browder and R.G., 1999). This study examines the influence of including projected shoreline changes under future sea states into hydrodynamic modeling within the Northern Gulf of Mexico (NGOM). The NGOM coastline is an economically and ecologically significant area, comprised of various bays, barrier islands and mainland beaches. Projected shorelines and nearshore morphology for the year 2050 are derived from the Coastal Vulnerability Index (CVI) shoreline change rates (Thieler and Hammer-Klose, 1999) and used in conjunction with the 'Bruun Rule effect'(Bruun, 1962). A large scale hydrodynamic model forced by astronomic tides and hurricane winds and pressures is used to simulate present conditions, a high projection of the 2050 sea state (18 in of SLR in accordance with Parris et al. (2012)) and the 2050 high sea state with 2050 shorelines to test the sensitivity of the system to the projected shoreline changes. Results show that shoreline changes coupled with sea level rise increases tidal inundation along shorelines, amplifies overtopping of barrier islands during storm surge events, and heightens inland storm surge inundation. It is critical to include estimates of shoreline and barrier island morphology when considering the hydrodynamics of extreme SLR projections. Aubrey, D. J. and G. S. Giese (1993). "Formation and Evolution of Multiple Tidal Inlets." Coastal Estuarine Stud. 44: 1-61. Browder, A. E. and D. R.G. (1999). "Pensacola Pass, FL Inlet Management Study". Coastal & Oceanographic Engineering Department, University of Florida, Prepared for Florida Department of Environmental Proection Bureau of Beaches and Coastal Systems. Bruun, P. (1962). "Sea-level rise as a cause of shore erosion." Proceedings of the American Society of Civil Engineers, Journal of the Waterways and Harbors Division 88: 117-130. Fitzgerald, D. M., M. S. Fenster, B. A. Argow and I. V. Buynevich (2008). "Coastal Impacts Due to Sea Level Rise." Annual Review Earth Planet Science 36: 601-647. Parris, A., P. Bromirski, V. Burkett, D. Cayan, M. Culver, J. Hall, R. Horton, K. Knuuti, R. Moss, J. Obeysekera, A. Sallenger and J. Weiss (2012). "Global Sea Level Rise Scenarios for the United States National Climate Assessment". NOAA Tech Memo OAR CPO-1: 37. Thieler, E. R. and E. S. Hammer-Klose (1999). "National Assessment of Coastal Vulnerability to Sea Level rise: Preliminary Results for the U.S. Atlantic Coast". Woods Hole, Massachusetts, US Geological Survey.

A 6,700 years sea-level record based on French Polynesian coral reefs

NASA Astrophysics Data System (ADS)

Hallmann, Nadine; Camoin, Gilbert; Eisenhauer, Anton; Vella, Claude; Samankassou, Elias; Botella, Albéric; Milne, Glenn; Fietzke, Jan; Dussouillez, Philippe

2015-04-01

Sea-level change during the Mid- to Late Holocene has a similar amplitude to the sea-level rise that is likely to occur before the end of the 21st century providing a unique opportunity to study the coastal response to sea-level change and to reveal an important baseline of natural climate variability prior to the industrial revolution. Mid- to Late Holocene relative sea-level change in French Polynesia was reconstructed using coral reef records from ten islands, which represent ideal settings for accurate sea-level studies because: 1) they can be regarded as tectonically stable during the relevant period (slow subsidence), 2) they are located far from former ice sheets (far-field), 3) they are characterized by a low tidal amplitude, and 4) they cover a wide range of latitudes which produces significantly improved constraints on GIA (Glacial Isostatic Adjustment) model parameters. Absolute U/Th dating of in situ coral colonies and their accurate positioning via GPS RTK (Real Time Kinematic) measurements is crucial for an accurate reconstruction of sea-level change. We focus mainly on the analysis of coral microatolls, which are sensitive low-tide recorders, as their vertical accretion is limited by the mean low water springs level. Growth pattern analysis allows the reconstruction of low-amplitude, high-frequency sea-level changes on centennial to sub-decadal time scales. A sea-level rise of less than 1 m is recorded between 6 and 3-3.5 ka, and is followed by a gradual fall in sea level that started around 2.5 ka and persisted until the past few centuries. The reconstructed sea-level curve therefore extends the Tahiti sea-level curve [Deschamps et al., 2012, Nature, 483, 559-564], and is in good agreement with a geophysical model tuned to fit far-field deglacial records [Bassett et al., 2005, Science, 309, 925-928].

Sea level history in Beringia during the past 250,000 years

USGS Publications Warehouse

Hopkins, D.M.

1973-01-01

This paper attempts to relate current knowledge of sea-level history in Beringia to the Broecker-van Donk "Termination" concept of climatic and sea-level history. The Einahnuhtan transgression is thought to represent Termination III, which according to Broecker and van Donk, took place about 225,000 y.a. The Kotzebuan transgression is thought to represent a positive fluctuation that modulated the generally falling sea level during the ensuing 100,000 yr. Sea level probably fell to about -135 m in the Bering Sea area during the maximum phase of the penultimate glaciation. The two Pelukian shorelines probably represent Termination II (about 125,000 yr BP in the Broecker-van Donk chronology) and one of the two positive fluctuations that modulated the generally falling sea level of early Wisconsinan time, about 105,000 and 80,000 y.a. according to Broecker and van Donk. Another positive modulation brought sea level to at least -20 m, about 30,000 y.a. Sea level evidently fell to between -90 and -100 m during the late Wisconsinan regression, but a substantial part of the outer Bering shelf remained submerged. Submerged shoreline features at -38m, -30 m, -24 to -20 m, and -12 to -10 m represent stillstands or slight regressions that modulated Termination I, the late Wisconsinan, and early Holocene recovery of sea level. ?? 1973.

How can climate change and engineered water conveyance affect sediment dynamics in the San Francisco Bay-Delta system?

USGS Publications Warehouse

Achete, Fernanda; Van der Wegen, Mick; Roelvink, Jan Adriaan; Jaffe, Bruce E.

2017-01-01

Suspended sediment concentration is an important estuarine health indicator. Estuarine ecosystems rely on the maintenance of habitat conditions, which are changing due to direct human impact and climate change. This study aims to evaluate the impact of climate change relative to engineering measures on estuarine fine sediment dynamics and sediment budgets. We use the highly engineered San Francisco Bay-Delta system as a case study. We apply a process-based modeling approach (Delft3D-FM) to assess the changes in hydrodynamics and sediment dynamics resulting from climate change and engineering scenarios. The scenarios consider a direct human impact (shift in water pumping location), climate change (sea level rise and suspended sediment concentration decrease), and abrupt disasters (island flooding, possibly as the results of an earthquake). Levee failure has the largest impact on the hydrodynamics of the system. Reduction in sediment input from the watershed has the greatest impact on turbidity levels, which are key to primary production and define habitat conditions for endemic species. Sea level rise leads to more sediment suspension and a net sediment export if little room for accommodation is left in the system due to continuous engineering works. Mitigation measures like levee reinforcement are effective for addressing direct human impacts, but less effective for a persistent, widespread, and increasing threat like sea level rise. Progressive adaptive mitigation measures to the changes in sediment and flow dynamics resulting from sea level rise may be a more effective strategy. Our approach shows that a validated process-based model is a useful tool to address long-term (decades to centuries) changes in sediment dynamics in highly engineered estuarine systems. In addition, our modeling approach provides a useful basis for long-term, process-based studies addressing ecosystem dynamics and health.

Evidence for the timing of sea-level events during MIS 3

NASA Astrophysics Data System (ADS)

Siddall, M.

2005-12-01

Four large sea-level peaks of millennial-scale duration occur during MIS 3. In addition smaller peaks may exist close to the sensitivity of existing methods to derive sea level during these periods. Millennial-scale changes in temperature during MIS 3 are well documented across much of the planet and are linked in some unknown, yet fundamental way to changes in ice volume / sea level. It is therefore highly likely that the timing of the sea level events during MIS 3 will prove to be a `Rosetta Stone' for understanding millennial scale climate variability. I will review observational and mechanistic arguments for the variation of sea level on Antarctic, Greenland and absolute time scales.

Polar ice-sheet contributions to sea level during past warm periods

NASA Astrophysics Data System (ADS)

Dutton, A.

2015-12-01

Recent sea-level rise has been dominated by thermal expansion and glacier loss, but the contribution from mass loss from the Greenland and Antarctic ice sheets is expected to exceed other contributions under future sustained warming. Due to limitations of existing ice sheet models and the lack of relevant analogues in the historical record, projecting the timing and magnitude of polar ice sheet mass loss in the future remains challenging. One approach to improving our understanding of how polar ice-sheet retreat will unfold is to integrate observations and models of sea level, ice sheets, and climate during past intervals of warmth when the polar ice sheets contributed to higher sea levels. A recent review evaluated the evidence of polar ice sheet mass loss during several warm periods, including interglacials during the mid-Pliocene warm period, Marine Isotope Stage (MIS) 11, 5e (Last Interglacial), and 1 (Holocene). Sea-level benchmarks of ice-sheet retreat during the first of these three periods, when global mean climate was ~1 to 3 deg. C warmer than preindustrial, are useful for understanding the long-term potential for future sea-level rise. Despite existing uncertainties in these reconstructions, it is clear that our present climate is warming to a level associated with significant polar ice-sheet loss in the past, resulting in a conservative estimate for a global mean sea-level rise of 6 meters above present (or more). This presentation will focus on identifying the approaches that have yielded significant advances in terms of past sea level and ice sheet reconstruction as well as outstanding challenges. A key element of recent advances in sea-level reconstructions is the ability to recognize and quantify the imprint of geophysical processes, such as glacial isostatic adjustment (GIA) and dynamic topography, that lead to significant spatial variability in sea level reconstructions. Identifying specific ice-sheet sources that contributed to higher sea levels is a challenge that is currently hindered by limited field evidence at high latitudes. Finally, I will explore the concept of how increasing the quantity and quality of paleo sea level and ice sheet reconstructions can lead to improved quantification of contemporary changes in ice sheets and sea level.

Anthropogenic sea level rise and adaptation in the Yangtze estuary

NASA Astrophysics Data System (ADS)

Cheng, H.; Chen, J.; Chen, Z.; Ruan, R.; Xu, G.; Zeng, G.; Zhu, J.; Dai, Z.; Gu, S.; Zhang, X.; Wang, H.

2016-02-01

Sea level rise is a major projected threat of climate change. There are regional variations in sea level changes, depending on both naturally the tectonic subsidence, geomorphology, naturally changing river inputs and anthropogenic driven forces as artificial reservoir water impoundment within the watershed and urban land subsidence driven by ground water depletion in the river delta. Little is known on regional sea level fall in response to the channel erosion due to the sediment discharge decline by reservoir interception in the upstream watershed, and water level rise driven by anthropogenic measures as the land reclamation, deep waterway regulation and fresh water reservoir construction to the sea level change in estuaries. Changing coastal cities are situated in the delta regions expected to be threatened in various degrees. Shanghai belongs to those cities. Here we show that the anthropogenic driven sea level rise in the Yangtze estuary from the point of view of the continuous hydrodynamic system consisted of river catchment, estuary and coastal sea. Land subsidence is cited as 4 mm/a (2011-2030). Scour depth of the estuarine channel by upstream engineering as Three Gauge Dam is estimated at 2-10 cm (2011-2030). The rise of water level by deep waterway and land reclamation is estimated at 8-10 cm (2011-2030). The relative sea level rise will be speculated about 10 -16 cm (2011-2030), which these anthropogenic sea level changes will be imposed into the absolute sea level rise 2 mm/a and tectonic subsidence 1 mm/a measured in 1990s. The action guideline to the sea level rise strategy in the Shanghai city have been proposed to the Shanghai government as (1) recent actions (2012-2015) to upgrade the city water supply and drainage engineering and protective engineering; (2) interim actions (2016-2020) to improve sea level monitoring and early warning system, and then the special, city, regional planning considering sea level rise; (3) long term actions (2021-2030) to implement both the safety and the transformation and development of the city.

Reconstructing Mid- to Late Holocene sea-level change from coral microatolls, French Polynesia

NASA Astrophysics Data System (ADS)

Hallmann, Nadine; Camoin, Gilbert; Eisenhauer, Anton; Botella, Alberic; Milne, Glenn; Vella, Claude; Samankassou, Elias; Pothin, Virginie; Dussouillez, Philippe; Fleury, Jules; Fietzke, Jan

2017-04-01

Coral microatolls are sensitive low-tide recorders, as their vertical accretion is limited by the mean low water springs level, and can be considered therefore as high-precision recorders of sea-level change. They are of pivotal importance to resolving the rates and amplitudes of millennial-to-century scale changes during periods of relative climate stability such as the Mid- to Late Holocene, which serves as an important baseline of natural variability prior to the industrial revolution. It provides therefore a unique opportunity to study coastal response to sea-level rise, even if the rates of sea-level rise during the Mid- to Late Holocene were lower than the current rates and those expected in the near future. Mid- to Late Holocene relative sea-level change in French Polynesia was reconstructed based on the coupling between absolute U/Th dating of in situ coral microatolls and their precise positioning via GPS RTK (Real Time Kinematic) measurements. The twelve studied islands represent ideal settings for accurate sea-level studies because: 1) they can be regarded as tectonically stable during the relevant period (slow subsidence), 2) they are located far from former ice sheets (far-field), 3) they are characterized by a low tidal amplitude, and 4) they cover a wide range of latitudes which produces significantly improved constraints on GIA (Glacial Isostatic Adjustment) model parameters. A step-like sea-level rise is evidenced between 6 and 3.9 ka leading to a short sea-level highstand of about a meter in amplitude between 3.9 and 3.6 ka. A sea-level fall, at an average rate of 0.3 mm.yr-1, is recorded between 3.6 and 1.2 ka when sea level approached its present position. In addition, growth pattern analysis of coral microatolls allows the reconstruction of low-amplitude, high-frequency sea-level change on centennial to sub-decadal time scales. The reconstructed sea-level curve extends the Tahiti last deglacial sea-level curve [Deschamps et al., 2012, Nature, 483, 559-564], and is in good agreement with a geophysical model tuned to fit far-field deglacial records [Bassett et al., 2005, Science, 309, 925-928].

A Quantitative Ecological Risk Assessment of the Toxicological Risks from Exxon Valdez Subsurface Oil Residues to Sea Otters at Northern Knight Island, Prince William Sound, Alaska

PubMed Central

Harwell, Mark A.; Gentile, John H.; Johnson, Charles B.; Garshelis, David L.; Parker, Keith R.

2010-01-01

A comprehensive, quantitative risk assessment is presented of the toxicological risks from buried Exxon Valdez subsurface oil residues (SSOR) to a subpopulation of sea otters (Enhydra lutris) at Northern Knight Island (NKI) in Prince William Sound, Alaska, as it has been asserted that this subpopulation of sea otters may be experiencing adverse effects from the SSOR. The central questions in this study are: could the risk to NKI sea otters from exposure to polycyclic aromatic hydrocarbons (PAHs) in SSOR, as characterized in 2001–2003, result in individual health effects, and, if so, could that exposure cause subpopulation-level effects? We follow the U.S. Environmental Protection Agency (USEPA) risk paradigm by: (a) identifying potential routes of exposure to PAHs from SSOR; (b) developing a quantitative simulation model of exposures using the best available scientific information; (c) developing scenarios based on calculated probabilities of sea otter exposures to SSOR; (d) simulating exposures for 500,000 modeled sea otters and extracting the 99.9% quantile most highly exposed individuals; and (e) comparing projected exposures to chronic toxicity reference values. Results indicate that, even under conservative assumptions in the model, maximum-exposed sea otters would not receive a dose of PAHs sufficient to cause any health effects; consequently, no plausible toxicological risk exists from SSOR to the sea otter subpopulation at NKI. PMID:20862194

Optical Modeling of Sea Salt Aerosols: The Effects of Nonsphericity and Inhomogeneity

NASA Astrophysics Data System (ADS)

Bi, Lei; Lin, Wushao; Wang, Zheng; Tang, Xiaoyun; Zhang, Xiaoyu; Yi, Bingqi

2018-01-01

The nonsphericity and inhomogeneity of marine aerosols (sea salts) have not been addressed in pertinent radiative transfer calculations and remote sensing studies. This study investigates the optical properties of nonspherical and inhomogeneous sea salts using invariant imbedding T-matrix simulations. Dry sea salt aerosols are modeled based on superellipsoidal geometries with a prescribed aspect ratio and roundness parameter. Wet sea salt particles are modeled as coated superellipsoids, as spherical particles with a superellipsoidal core, and as homogeneous spheres depending on the level of relative humidity. Aspect ratio and roundness parameters are found to be critical to interpreting the linear depolarization ratios (LDRs) of NaCl crystals from laboratory measurements. The optimal morphology parameters of NaCl necessary to reproduce the measurements are found to be consistent with data gleaned from an electron micrograph. The LDRs of wet sea salts are computed based on inhomogeneous models and compared with the measured data from ground-based LiDAR. The dependence of the LDR on relative humidity is explicitly considered. The increase in the LDR with relative humidity at the initial phase of deliquescence is attributed to both the size increase and the inhomogeneity effect. For large humidity values, the LDR substantially decreases because the overall particle shape becomes more spherical and the inhomogeneity effect in a particle on the LDR is suppressed for submicron sea salts. However, the effect of inhomogeneity on optical properties is pronounced for coarse-mode sea salts. These findings have important implications for atmospheric radiative transfer and remote sensing involving sea salt aerosols.