Matching spatial property rights fisheries with scales of fish dispersal.

PubMed

White, Crow; Costello, Christopher

2011-03-01

Regulation of fisheries using spatial property rights can alleviate competition for high-value patches that hinders economic efficiency in quota-based, rights-based, and open-access management programs. However, efficiency gains erode when delineation of spatial rights constitutes incomplete ownership of the resource, thereby degrading its local value and promoting overexploitation. Incomplete ownership may be particularly prevalent in the spatial management of mobile fishery species. We developed a game-theoretic bioeconomic model of spatial property rights representing territorial user rights fisheries (TURF) management of nearshore marine fish and invertebrate species with mobile adult and larval life history stages. Strategic responses by fisheries in neighboring management units result in overexploitation of the stock and reduced yields for each fishery compared with those attainable without resource mobility or with coordination or sole control in fishing effort. High dispersal potential of the larval stage, a common trait among nearshore fishery species, coupled with scaling of management units to only capture adult mobility, a common characteristic of many nearshore TURF programs, in particular substantially reduced stock levels and yields. In a case study of hypothetical TURF programs of nearshore fish and invertebrate species, management units needed to be tens of kilometers in alongshore length to minimize larval export and generate reasonable returns to fisheries. Cooperation and quota regulations represent solutions to the problem that need to be quantified in cost and integrated into the determination of the acceptability of spatial property rights management of fisheries.

Wave climate and nearshore lakebed response, Illinois Beach State Park, Lake Michigan

USGS Publications Warehouse

Booth, J.S.

1994-01-01

Only under these major storm conditions is there a realistic potential for wave-lakebed interaction (and associated wind-driven currents) to cause a significant net modification to the outer nearshore lakebed which, in turn, may promulgate change in the inner nearshore (surf) zone. Analysis of bathymetric and sediment grain-size data, used in conjuction with published wave hindcast data, wave propagation modeling, and previous studies in the area, indicates that this potential occurs, most likely, on a scale of years. -from Author

Application of autonomous robotized systems for the collection of nearshore topographic changing and hydrodynamic measurements

NASA Astrophysics Data System (ADS)

Belyakov, Vladimir; Makarov, Vladimir; Zezyulin, Denis; Kurkin, Andrey; Pelinovsky, Efim

2015-04-01

Hazardous phenomena in the coastal zone lead to the topographic changing which are difficulty inspected by traditional methods. It is why those autonomous robots are used for collection of nearshore topographic and hydrodynamic measurements. The robot RTS-Hanna is well-known (Wubbold, F., Hentschel, M., Vousdoukas, M., and Wagner, B. Application of an autonomous robot for the collection of nearshore topographic and hydrodynamic measurements. Coastal Engineering Proceedings, 2012, vol. 33, Paper 53). We describe here several constructions of mobile systems developed in Laboratory "Transported Machines and Transported Complexes", Nizhny Novgorod State Technical University. They can be used in the field surveys and monitoring of wave regimes nearshore.

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

Schultz, A.L.

The Lopez Field was discovered June 27, 1936, by the Mills Bennett Production Co.'s Jesus Lopez No. 1 near the middle of the west half of Sect. 73 (Tract 10) in Webb County, Texas. Over 380 wells have been drilled in the Lopez Field and over 180 of these were in what is now the South Lopez Unit. In 1959, water injection commenced and since then the field has been under some type of secondary recovery program. The first Mirando sand is an eocene lenticular sand composed of 2 units separated by a limy sand permeability barrier. The upper unitmore » appears to have been associated with a transgressive nearshore environment and the lower unit has been deposited in the Delta Plain facies of the high-constructive Delta. The abundance of lignite seen in cores in various wells places the deposition of both units very nearshore.« less

Late Pleistocene sediments and fossils near the mouth of Mad River, Humboldt County, California: Facies analysis, sequence development, and possible age correlation

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

Harvey, E.W.

Study of late Pleistocene-age sediments near the mouth of the Mad River revealed a sequence of nearshore marine and shallow bay deposits. This sequence, bounded by unconformities, is informally named the Mouth of Mad unit. The Mouth of mad unit can be divided into four distinct depositional facies at the study site. The lowest facies are the Nearshore Sand and Estuarine Mud, which lie unconformably on a paleosol. The sand facies grades upward into a high-energy, interbedded Nearshore Sand and Gravel facies containing storm and rip-channel deposits. Above the sand and gravel is a Strand-Plain Sand facies. This sand ismore » overlain by a laterally variable sequence of shell-rich Bay facies. The bay deposits can be further divided into five subfacies: (1) a Bioturbated Sand; (2) a Lower Tidal Flat Mud; (3) a Mixed Sand and Mud; (4) an oyster-rich Bay Mud; and (5) an Upper Tidal Flat Mud. The bay sequence is overlain unconformably by younger late Pleistocene-age marine terrace deposits. The depositional environments represented by these facies progress from a shoreline estuary to nearshore deposits, above storm wave base, and slowly back to shoreline and finally shallow bay conditions. The Mouth of Mad unit represents a transgressive-regressive sequence, involving the development of a protective spit. The uppermost mud within the Mouth of Mad unit has been dated, using thermoluminescence age estimation, at 176 [+-] 33 ka, placing it in the late Pleistocene. The Mouth of Mad unit appears to be younger than the fossiliferous deposits at Elk Head, Crannell Junction, Trinidad Head, Moonstone Beach, and the Falor Formation near Maple Creek, and possibly time equivalent with gravel deposits exposed at the western end of School Road in McKinleyville.« less

Morphologic Response and Sediment Redistribution of the Beach and Nearshore Sand Bars due to Extratropical and Tropical Storm Forcing: a Spatial and Temporal Analysis

NASA Astrophysics Data System (ADS)

Miselis, J. L.; McNinch, J. E.

2005-05-01

Shore-oblique bars and associated exposures of an underlying geologic stratum in the nearshore have been documented along the US East Coast and have been linked to shoreline erosional hotspots. While earlier studies acknowledged that the bedforms responded to extratropical and tropical storms, neither quantified the extent of sediment redistribution after the events. An approach that encompasses actual volume measurements across the nearshore-beach down to a non-sandy stratum and quantifies the response of the beach and the nearshore to the same hydrodynamic forcing will enable a better understanding of the exchange of sediment between the two regions. Total nearshore sediment volume has been shown to be a first-order contributor to the behavior of the shoreline. This volumetric approach is employed in the analysis of morphological changes and the redistribution of sediment in the nearshore and beach following storms. A regional survey from 2002 provides the initial, fair-weather morphologic state of the nearshore (1.5-15m water depth) spanning 40 km of the North Carolina Outer Banks. Four small-scale surveys were conducted in subsequent years, focusing on four 1-km2 regions within the initial 2002 survey area. The smaller regions were selected on the basis of the morphological state observed during the 2002 survey and historical shoreline behavior. Data were collected in March 2003 following a Northeaster; in May 2003 following an extended period of fair weather conditions; in November 2003 following Hurricane Isabel; and finally, in June 2004 after another period of fair weather. A swath bathymetry system was used to collect bathymetry and side scan sonar (acoustic backscatter) and a high-resolution chirp sub-bottom profiler imaged the shallow sub-surface geology of the nearshore. In addition, RTK-GPS was used to map the sub-aerial beach at each 1-km2 site from the toe of the dune to the water line for the May 2003, November 2003, and June 2004 sampling periods. This sampling regime and data set offers a unique opportunity 1) to compare the simultaneous response of the beach and the nearshore to storms and 2) to investigate how the response of the beach and the nearshore varies depending on sandbar morphology and differences in the geologic framework. Three-dimensional maps of the beach and nearshore, from the toe of the dune to the 15m isobath, are used to demonstrate changes in total shoreface volume after storms and during recovery. Understanding the redistribution of sediment in the context of volumetric change enables the quantification of the exchange of sediment between the beach and the nearshore during large-scale forcing events.

Data on nearshore wave process and surficial beach deposits, central Tamil Nadu coast, India.

PubMed

Joevivek, V; Chandrasekar, N

2017-08-01

The chronicles of nearshore morphology and surficial beach deposits provide valuable information about the nature of the beach condition and the depositional environment. It imparts an understanding about the spatial and temporal relationship of nearshore waves and its influence over the distribution of beach sediments. This article contains data about wave and sediment dynamics of the ten sandy beaches along the central Tamil Nadu coast, India. This present dataset comprises nearshore wave parameters, breaker wave type, beach morphodynamic state, grain size distribution and weight percentage of heavy and light mineral distribution. The dataset will figure out the beach morphology and hydrodynamic condition with respect to the different monsoonal season. This will act as a field reference to realize the coastal dynamics in an open sea condition. The nearshore entities were obtained from the intensive field survey between January 2011 and December 2011, while characteristics of beach sediments are examined by the chemical process in the laboratory environment.

Exxon Valdez oil spill. State/federal natural resource damage assessment. Impact of the oil spill on juvenile pink and chum salmon and their prey in critical nearshore habitats. Fish/shellfish study number 4. Final report

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

NONE

1994-01-01

The objective of the study was to determine the impact of the Exxon Valdez oil spill on juvenile pink and chum salmon during their initial period of residency in nearshore marine habitats of western Prince William Sound. In oiled locations, both pink and chum salmon fry in the nearshore marine environment observations and laboratory experiments indicated that ingestion of whole oil or oil-contaminated prey was an important route of contamination.

GEO-CAPE Coastal Ocean Ecosystem Dynamics White Paper ...

EPA Pesticide Factsheets

The Clean Water Act protects all navigable waters in the United States (CWA, 1988). The objective of the CWA is to "restore and maintain the chemical, physical, and biological integrity of the Nation's waters." This Federal mandate authorizes states, tribes, and U.S. territories, with guidance and oversight from the U.S. Environmental Protection Agency (EPA), to develop and implement water quality standards to protect the human and aquatic life uses of the Nation’s waterways. Water quality standards include designated uses, defined as the services that a water body supports such as drinking water, aquatic life, harvestable species, and recreation. These standards under the CWA Section 304(a) are applicable within state waters, defined as less than 3 nautical miles from shore. Therefore, a majority of research by the EPA addresses near-shore coastal waters within 3 nautical miles, estuaries and lakes where applicable water quality regulation could be implemented. Policy makers and environmental managers in EPA’s program and regional offices need tools enabling them to assess the sustainability of watershed ecosystems, and the services they provide, under current and future land use practices. The typical 1km resolution and current Case 1 algorithms of SeaWiFS, MODIS, and VIIRS provide limited assessments of near-shore coastal waters, estuaries and lakes. It has proven difficult to adequately resolve and derive products in smaller estuaries or waters in proxim

Dynamics of Nearshore Sand Bars and Infra-gravity Waves: The Optimal Theory Point of View

NASA Astrophysics Data System (ADS)

Bouchette, F.; Mohammadi, B.

2016-12-01

It is well known that the dynamics of near-shore sand bars are partly controlled by the features (location of nodes, amplitude, length, period) of the so-called infra-gravity waves. Reciprocally, changes in the location, size and shape of near-shore sand bars can control wave/wave interactions which in their turn alter the infra-gravity content of the near-shore wave energy spectrum. The coupling infra-gravity / near-shore bar is thus definitely two ways. Regarding numerical modelling, several approaches have already been considered to analyze such coupled dynamics. Most of them are based on the following strategy: 1) define an energy spectrum including infra-gravity, 2) tentatively compute the radiation stresses driven by this energy spectrum, 3) compute sediment transport and changes in the seabottom elevation including sand bars, 4) loop on the computation of infra-gravity taking into account the morphological changes. In this work, we consider an alternative approach named Nearshore Optimal Theory, which is a kind of breakdown point of view for the modeling of near-shore hydro-morphodynamics and wave/ wave/ seabottom interactions. Optimal theory applied to near-shore hydro-morphodynamics arose with the design of solid coastal defense structures by shape optimization methods, and is being now extended in order to model dynamics of any near-shore system combining waves and sand. The basics are the following: the near-shore system state is through a functional J representative of the energy of the system in some way. This J is computed from a model embedding the physics to be studied only (here hydrodynamics forced by simple infra-gravity). Then the paradigm is to say that the system will evolve so that the energy J tends to minimize. No really matter the complexity of wave propagation nor wave/bottom interactions. As soon as J embeds the physics to be explored, the method does not require a comprehensive modeling. Near-shore Optimal Theory has already given promising results for the generation of near-shore sand bar from scratch and their growth when forced by fair-weather waves. Here, we use it to explore the coupling between a very simple infra-gravity content and the nucleation of near-shore sand-bars. It is shown that even a very poor infra-gravity content strongly improves the generation of sand bars.

Wave energy converter effects on wave propagation: A sensitivity study in Monterey Bay, CA

NASA Astrophysics Data System (ADS)

Chang, G.; Jones, C. A.; Roberts, J.; Magalen, J.; Ruehl, K.; Chartrand, C.

2014-12-01

The development of renewable offshore energy in the United States is growing rapidly and wave energy is one of the largest resources currently being evaluated. The deployment of wave energy converter (WEC) arrays required to harness this resource could feasibly number in the hundreds of individual devices. The WEC arrays have the potential to alter nearshore wave propagation and circulation patterns and ecosystem processes. As the industry progresses from pilot- to commercial-scale it is important to understand and quantify the effects of WECs on the natural nearshore processes that support a local, healthy ecosystem. To help accelerate the realization of commercial-scale wave power, predictive modeling tools have been developed and utilized to evaluate the likelihood of environmental impact. At present, direct measurements of the effects of different types of WEC arrays on nearshore wave propagation are not available; therefore wave model simulations provide the groundwork for investigations of the sensitivity of model results to prescribed WEC characteristics over a range of anticipated wave conditions. The present study incorporates a modified version of an industry standard wave modeling tool, SWAN (Simulating WAves Nearshore), to simulate wave propagation through a hypothetical WEC array deployment site on the California coast. The modified SWAN, referred to as SNL-SWAN, incorporates device-specific WEC power take-off characteristics to more accurately evaluate a WEC device's effects on wave propagation. The primary objectives were to investigate the effects of a range of WEC devices and device and array characteristics (e.g., device spacing, number of WECs in an array) on nearshore wave propagation using SNL-SWAN model simulations. Results showed that significant wave height was most sensitive to variations in WEC device type and size and the number of WEC devices in an array. Locations in the lee centerline of the arrays in each modeled scenario showed the largest potential changes in wave height. The SNL-SWAN model simulations for various WEC devices provide the basis for a solid model understanding, giving the confidence necessary for future WEC evaluations.

Dioctyl sulfosuccinate analysis in near-shore Gulf of Mexico water by direct-injection liquid chromatography-tandem mass spectrometry.

PubMed

Mathew, Johnson; Schroeder, David L; Zintek, Lawrence B; Schupp, Caitlin R; Kosempa, Michael G; Zachary, Adam M; Schupp, George C; Wesolowski, Dennis J

2012-03-30

Dioctyl sulfosuccinate (DOSS) was a major component of the dispersants most used in the 2010 Deepwater Horizon Oil Spill incident response. This analytical method quantifies salt water DOSS concentrations to a reporting limit of 20 μg/L, which was below the United States Environmental Protection Agency's (U.S. EPA) 40 μg/L DOSS Aquatic Life Benchmark. DOSS in Gulf of Mexico water samples were analyzed by direct-injection reversed-phase liquid chromatography-tandem mass spectrometry (LC-MS/MS). Sample preparation with 50% acetonitrile (ACN) enabled quantitative transfer of DOSS and increased DOSS response 20-fold by reducing aggregation. This increased sensitivity enabled the detection of a confirmatory transition over the calibration range of 10-200 μg/L. U.S. EPA Region 5 and Region 6 laboratories analyzed hundreds of near-shore surface Gulf of Mexico water samples, none contained more than the 20 ppb reporting limit. The matrix spike DOSS/deuterated surrogate (DOSS-D34) correlation of determination varied with mobile phase modifier (ammonium formate R(2)=0.95 and formic acid R(2)=0.27). Using ammonium formate, DOSS-D34 accurately measured DOSS matrix effect. The near-shore sodium concentrations varied more than 10,000-fold, but were not strongly correlated with DOSS recovery. DOSS detection by LC-MS/MS enabled rapid analysis which was valuable in guiding incident response. Published by Elsevier B.V.

An evaluation of effects of groundwater exchange on nearshore habitats and water quality of western Lake Erie

USGS Publications Warehouse

Haack, Sheridan K.; Neff, Brian P.; Rosenberry, Donald O.; Savino, Jacqueline F.; Lundstrom, Scott C.

2005-01-01

Historically, the high potentiometric surface of groundwater in the Silurian/Devonian carbonate aquifer in Monroe County, MI resulted in discharge of highly mineralized, SO4-rich groundwater to the Lake Erie shoreline near both Erie State Game Area (ESGA) and Pointe Mouillee State Game Area (PMSGA). Recently, regional groundwater levels near PMSGA have been drawn down as much as 45 m below lake level in apparent response to quarry dewatering. From August to November of 2003, we conducted preliminary studies of groundwater flow dynamics and chemistry, shallow lake water chemistry, and fish and invertebrate communities at both sites. Consistent with regional observations, groundwater flow direction in the nearshore at ESGA was upward, or toward Lake Erie, and shallow nearshore groundwater chemistry was influenced by regional groundwater chemistry. In contrast, at PMSGA, the groundwater flow potential was downward and lake water, influenced by quarry discharge seeping downward into nearshore sediments, produced a different lake and shallow groundwater chemistry than at ESGA. Although the invertebrate and young fish community was similar at the two sites, taxonomic groups tolerant of degraded water quality were more prevalent at PMSGA. Sensitive taxa were more prevalent at ESGA. We propose a conceptual model, based on well-described models of groundwater/seawater interaction along coastal margins, to describe the interconnection among geologic, hydrologic, chemical, and biological processes in the different nearshore habitats of Lake Erie, and we identify processes that warrant further detailed study in the Great Lakes.

The Performance of Nearshore Dredge Disposal at Ocean Beach, San Francisco, California, 2005-2007

USGS Publications Warehouse

Barnard, Patrick L.; Erikson, Li H.; Hansen, Jeff E.; Elias, Edwin

2009-01-01

Ocean Beach, California, contains an erosion hot spot in the shadow of the San Francisco ebb tidal delta that threatens valuable public infrastructure as well as the safe recreational use of the beach. In an effort to reduce the erosion at this location a new plan for the management of sediment dredged annually from the main shipping channel at the mouth of San Francisco Bay was implemented in May 2005 by the United States Army Corps of Engineers, San Francisco District (USACE). The USACE designated a temporary nearshore dredge disposal site for the annual disposal of about 230,000 m3 (300,000 yd3) of sand about 750 m offshore and slightly south of the erosion hot spot, in depths between approximately 9 and 14 m. The site has now been used three times for a total sediment disposal of about 690,000 m3 (about 900,000 yds3). The disposal site was chosen because it is in a location where strong tidal currents and open-ocean waves can potentially feed sediment toward the littoral zone in the reach of the beach that is experiencing critical erosion, as well as prevent further scour on an exposed outfall pipe. The onshore migration of sediment from the target disposal location might feed the primary longshore bar or the nearshore zone, and provide a buffer to erosion that peaks during winter months when large waves impact the region. The United States Geological Survey (USGS) has been monitoring and modeling the bathymetric evolution of the test dredge disposal site and the adjacent coastal region since inception in May 2005. This paper reports on the first 2.5 years of this monitoring program effort (May 2005 to December 2007) and assesses the short-term coastal response. Here are the key findings of this report: *Approximately half of the sediment that has been placed in the nearshore dredge-disposal site during the 2.5 years of this study remains within the dredge focus area. *In the winter of 2006-7, large waves transported the dredge-mound material onshore. *High rates of seasonal cross-shore sediment transport mask any potential profile change in the Coastal Profiling System data due to dredge placement. *Pockets of accretion have been recorded by topographic surveying adjacent to the dredge site, but it is unclear if the accretion is linked to the nourishment. *Cross-shore profile modeling suggests that dredge material must be placed in water depths no greater than 5 m to drive a positive shoreline response. *Area modeling demonstrates that the new dredge site increases wave dissipation and modifies local sediment-transport patterns, although the effect on the nearshore morphology is largely negligible. *Any increase in beach width or wave energy-dissipation related to the nourishment is likely to be realized only in the vicinity directly onshore of the nourishment site, which is several hundred meters south of the area of critical erosion. *Larger waves from the northwest and smaller waves from the west or southwest contribute most to the sediment transport from the dredge mound onshore.

California State Waters Map Series: Drakes Bay and vicinity, California

USGS Publications Warehouse

Watt, Janet T.; Dartnell, Peter; Golden, Nadine E.; Greene, H. Gary; Erdey, Mercedes D.; Cochrane, Guy R.; Johnson, Samuel Y.; Hartwell, Stephen R.; Kvitek, Rikk G.; Manson, Michael W.; Endris, Charles A.; Dieter, Bryan E.; Sliter, Ray W.; Krigsman, Lisa M.; Lowe, Erik N.; Chinn, John L.; Watt, Janet T.; Cochran, Susan A.

2015-01-01

Sediment transport in the map area largely is controlled by surface waves and tidal currents in the nearshore and, at depths greater than 20 to 30 m, by tidal and subtidal currents. In the map area, nearshore littoral drift of sand and coarse sediment is to the south, owing to the dominant west-northwest swell direction, and scour from large waves and tidal currents removes and redistributes sediment over large areas of the inner shelf. Tidal currents are particularly strong over the shelf in the map area, and they dominate the current regime in the nearshore. Further offshore, bottom currents generally flow to the northwest, distributing finer grained sediment accordingly.

Estimating the Risk of Tropical Cyclone Characteristics Along the United States Gulf of Mexico Coastline Using Different Statistical Approaches

NASA Astrophysics Data System (ADS)

Trepanier, J. C.; Ellis, K.; Jagger, T.; Needham, H.; Yuan, J.

2017-12-01

Tropical cyclones, with their high wind speeds, high rainfall totals and deep storm surges, frequently strike the United States Gulf of Mexico coastline influencing millions of people and disrupting off shore economic activities. Events, such as Hurricane Katrina in 2005 and Hurricane Isaac in 2012, can be physically different but still provide detrimental effects due to their locations of influence. There are a wide variety of ways to estimate the risk of occurrence of extreme tropical cyclones. Here, the combined risk of tropical cyclone storm surge and nearshore wind speed using a statistical copula is provided for 22 Gulf of Mexico coastal cities. Of the cities considered, Bay St. Louis, Mississippi has the shortest return period for a tropical cyclone with at least a 50 m s-1 nearshore wind speed and a three meter surge (19.5 years, 17.1-23.5). Additionally, a multivariate regression model is provided estimating the compound effects of tropical cyclone tracks, landfall central pressure, the amount of accumulated precipitation, and storm surge for five locations around Lake Pontchartrain in Louisiana. It is shown the most intense tropical cyclones typically approach from the south and a small change in the amount of rainfall or landfall central pressure leads to a large change in the final storm surge depth. Data are used from the National Hurricane Center, U-Surge, SURGEDAT, and Cooperative Observer Program. The differences in the two statistical approaches are discussed, along with the advantages and limitations to each. The goal of combining the results of the two studies is to gain a better understanding of the most appropriate risk estimation technique for a given area.

Blinded by the light? Nearshore energy pathway coupling and relative predator biomass increase with reduced water transparency across lakes.

PubMed

Tunney, Tyler D; McCann, Kevin S; Jarvis, Lauren; Lester, Nigel P; Shuter, Brian J

2018-04-01

Habitat coupling is a concept that refers to consumer integration of resources derived from different habitats. This coupling unites fundamental food web pathways (e.g., cross-habitat trophic linkages) that mediate key ecological processes such as biomass flows, nutrient cycling, and stability. We consider the influence of water transparency, an important environmental driver in aquatic ecosystems, on habitat coupling by a light-sensitive predator, walleye (Sander vitreus), and its prey in 33 Canadian lakes. Our large-scale, across-lake study shows that the contribution of nearshore carbon (δ 13 C) relative to offshore carbon (δ 13 C) to walleye is higher in less transparent lakes. To a lesser degree, the contribution of nearshore carbon increased with a greater proportion of prey in nearshore compared to offshore habitats. Interestingly, water transparency and habitat coupling predict among-lake variation in walleye relative biomass. These findings support the idea that predator responses to changing conditions (e.g., water transparency) can fundamentally alter carbon pathways, and predator biomass, in aquatic ecosystems. Identifying environmental factors that influence habitat coupling is an important step toward understanding spatial food web structure in a changing world.

Molecular-based approaches to characterize coastal microbial community and their potential relation to the trophic state of Red Sea

PubMed Central

Ansari, Mohd Ikram; Harb, Moustapha; Jones, Burton; Hong, Pei-Ying

2015-01-01

Molecular-based approaches were used to characterize the coastal microbiota and to elucidate the trophic state of Red Sea. Nutrient content and enterococci numbers were monitored, and used to correlate with the abundance of microbial markers. Microbial source tracking revealed the presence of >1 human-associated Bacteroides spp. at some of the near-shore sampling sites and at a heavily frequented beach. Water samples collected from the beaches had occasional exceedances in enterococci numbers, higher total organic carbon (TOC, 1.48–2.18 mg/L) and nitrogen (TN, 0.15–0.27 mg/L) than that detected in the near-shore waters. Enterococci abundances obtained from next-generation sequencing did not correlate well with the cultured enterococci numbers. The abundance of certain genera, for example Arcobacter, Pseudomonas and unclassified Campylobacterales, was observed to exhibit slight correlation with TOC and TN. Low abundance of functional genes accounting for up to 41 copies/L of each Pseudomonas aeruginosa and Campylobacter coli were detected. Arcobacter butzleri was also detected in abundance ranging from 111 to 238 copies/L. Operational taxonomic units (OTUs) associated with cyanobacteria, Prochlorococcus, Ostreococcus spp. and Gramella were more prevalent in waters that were likely impacted by urban runoffs and recreational activities. These OTUs could potentially serve as quantifiable markers indicative of the water quality. PMID:25758166

A High Resolution Hydrodynamic Model of Puget Sound to Support Nearshore Restoration Feasibility Analysis and Design

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

Khangaonkar, Tarang; Yang, Zhaoqing

2011-01-01

Estuarine and coastal hydrodynamic processes are sometimes neglected in the design and planning of nearshore restoration actions. Despite best intentions, efforts to restore nearshore habitats can result in poor outcomes if circulation and transport which also affect freshwater-saltwater interactions are not properly addressed. Limitations due to current land use can lead to selection of sub-optimal restoration alternatives that may result in undesirable consequences, such as flooding, deterioration of water quality, and erosion, requiring immediate remedies and costly repairs. Uncertainty with achieving restoration goals, such as recovery of tidal exchange, supply of sediment and nutrients, and establishment of fish migration pathways,more » may be minimized by using numerical models designed for application to the nearshore environment. A high resolution circulation and transport model of the Puget Sound, in the state of Washington, was developed to assist with nearshore habitat restoration design and analysis, and to answer the question “can we achieve beneficial restoration outcomes at small local scale, as well as at a large estuary-wide scale?” The Puget Sound model is based on an unstructured grid framework to define the complex Puget Sound shoreline using a finite volume coastal ocean model (FVCOM). The capability of the model for simulating the important nearshore processes, such as circulation in complex multiple tidal channels, wetting and drying of tide flats, and water quality and sediment transport as part of restoration feasibility, are illustrated through examples of restoration projects in Puget Sound.« less

Use of a Land-Based, Dual-Parameter Analyzer for Tracking Ocean Acidification in Nearshore Coastal Habitats

NASA Astrophysics Data System (ADS)

Shea, M.; Alin, S. R.; Evans, W.; Sutton, A.; Hales, B. R.; Newton, J.; Feely, R. A.

2016-12-01

In 2007 to 2008, U.S. Pacific Northwest shellfish hatcheries experienced unprecedented larval mortality, attributed to upwelling along the Washington-Oregon coast that brought seawater enriched in anthropogenic CO2 and undersaturated with respect to aragonite to the surface. In response, several hatcheries have been outfitted with land-based analyzers to measure CO2 partial pressure (pCO2) and total dissolved CO2 (TCO2) through U.S. IOOS and NOAA OAP funding. This analyzer, developed at Oregon State University and known as the `Burke-O-Lator,' allows users to track CO2 system parameters in real-time. The data are available in near real-time on the IOOS Pacific Region Ocean Acidification (IPACOA) data portal, which feeds to the Global Ocean Acidification Observing Network (GOA-ON). Here, we explore the broader use of this system as an environmental monitoring tool. Most of the high-quality OA time-series locations in GOA-ON are in the open and coastal ocean, yet many areas of biological interest—such as shellfish hatcheries, shellfish farms, and coastal laboratories—are in the nearshore area of the coastal zone. A truly globally integrated assessment of OA must include nearshore conditions, which have been shown to be quite different in terms of variability, drivers, and range. We evaluated two pCO2 time-series from the coastal nearshore: the Taylor Shellfish Hatchery Burke-O-Lator system on the shore of Dabob Bay in Puget Sound, WA, and the nearby but offshore Dabob ORCA buoy MAPCO2 system within the bay. Preliminary comparison of three years of data reveals similar patterns despite differences in location and seawater intake depth, highlighting the opportunity for the addition of coupled nearshore biology and biogeochemistry measurements in GOA-ON. In addition, the well-calibrated, dual-parameter nature of the system is important for constraining nearshore chemistry, as biology, groundwater, and river inputs can lead to strong variability in carbonate chemistry and the potential for decoupled pH and aragonite saturation state dynamics. With the increasing threat of corrosive conditions due to ocean acidification, continued work on integrating the now seven Burke-O-Lator sites into GOA-ON will improve our ability to understand, monitor, mitigate, and adapt to nearshore carbonate chemistry.

Multi-scale modeling of Puget Sound using an unstructured-grid coastal ocean model: from tide flats to estuaries and coastal waters

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

Yang, Zhaoqing; Khangaonkar, Tarang

2010-11-19

Water circulation in Puget Sound, a large complex estuary system in the Pacific Northwest coastal ocean of the United States, is governed by multiple spatially and temporally varying forcings from tides, atmosphere (wind, heating/cooling, precipitation/evaporation, pressure), and river inflows. In addition, the hydrodynamic response is affected strongly by geomorphic features, such as fjord-like bathymetry and complex shoreline features, resulting in many distinguishing characteristics in its main and sub-basins. To better understand the details of circulation features in Puget Sound and to assist with proposed nearshore restoration actions for improving water quality and the ecological health of Puget Sound, a high-resolutionmore » (around 50 m in estuaries and tide flats) hydrodynamic model for the entire Puget Sound was needed. Here, a threedimensional circulation model of Puget Sound using an unstructured-grid finite volume coastal ocean model is presented. The model was constructed with sufficient resolution in the nearshore region to address the complex coastline, multi-tidal channels, and tide flats. Model open boundaries were extended to the entrance of the Strait of Juan de Fuca and the northern end of the Strait of Georgia to account for the influences of ocean water intrusion from the Strait of Juan de Fuca and the Fraser River plume from the Strait of Georgia, respectively. Comparisons of model results, observed data, and associated error statistics for tidal elevation, velocity, temperature, and salinity indicate that the model is capable of simulating the general circulation patterns on the scale of a large estuarine system as well as detailed hydrodynamics in the nearshore tide flats. Tidal characteristics, temperature/salinity stratification, mean circulation, and river plumes in estuaries with tide flats are discussed.« less

Shallow stratigraphy of the Skagit River Delta, Washington, derived from sediment cores

USGS Publications Warehouse

Grossman, Eric E.; George, Douglas A.; Lam, Angela

2011-01-01

Sedimentologic analyses of 21 sediment cores, ranging from 0.4 to 9.6 m in length, reveal that the shallow geologic framework of the Skagit River Delta, western Washington, United States, has changed significantly since 1850. The cores collected from elevations of 3.94 to -2.41 m (relative to mean lower low water) along four cross-shore transects between the emergent marsh and delta front show relatively similar environmental changes across an area spanning ~75 km2. Offshore of the present North Fork Skagit River and South Fork Skagit River mouths where river discharge is focused by diked channels through the delta, the entire 5–7-km-wide tidal flats are covered with 1–2 m of cross-bedded medium-to-coarse sands. The bottoms of cores, collected in these areas are composed of mud. A sharp transition from mud to a cross-bedded sand unit indicates that the tidal flats changed abruptly from a calm environment to an energetic one. This is in stark contrast to the Martha's Bay tidal flats north of the Skagit Bay jetty that was completed in the 1940s to protect the newly constructed Swinomish Channel from flooding and sedimentation. North of the jetty, mud ranging from 1 to 2 m thick drapes a previously silt- and sand-rich tidal flat. The silty sand is a sediment facies that would be expected there where North Fork Skagit River sedimentation occurred prior to jetty emplacement. This report describes the compositional and textural properties of the sediment cores by using geophysical, photographic, x-radiography, and standard sediment grain-size and carbon-analytical methods. The findings help to characterize benthic habitat structure and sediment transport processes and the environmental changes that have occurred across the nearshore of the Skagit River Delta. The findings will be useful for quantifying changes to nearshore marine resources, including impacts resulting from diking, river-delta channelization, shoreline development, and natural variations in fluvial-sediment inputs. These results also provide important quantitative data on the amount of sediment delivered to the nearshore from the Skagit River for use in calculating sediment budgets for application to watershed planning and wetland and coastal-ecosystem restoration.

Nearshore sediment monitoring for the Stormwater Action Monitoring (SAM) Program, Puget Sound, western Washington

USGS Publications Warehouse

Black, Robert W.; Barnes, Abby; Elliot, Colin; Lanksbury, Jennifer

2018-06-26

Chemicals such as metals and organics (polychlorinated biphenyl [PCBs], polybrominated diphenyl ethers [PBDEs], polycyclic aromatic hydrocarbons [PAHs], and phthalates) continue to enter Puget Sound, western Washington, from point sources (such as industrial and municipal outfalls) and combined sewer outfalls and non-point sources (such as stormwater runoff). Runoff during storm events has been identified as a major source of contamination entering Puget Sound and has been implicated in the degradation of nearshore habitats and biota. Metals, organic chemicals, and other pollutants are known to accumulate in sediments such as those present along the shoreline of Puget Sound. In addition to chemical contaminants, small plastic particles (known as microplastics), found in marine waters of Puget Sound and suspected of being in aquatic sediments, are a potential concern because they can be ingested by animals and are suspected of transporting sorbed chemicals such as PCBs and metals.The Stormwater Work Group of Puget Sound (SWG) (composed of State and municipal stormwater permittees, and other stakeholders) developed a strategy to address sediment conditions in the nearshore environment of Puget Sound. As part of this strategy, the SWG developed a regional stormwater monitoring strategy designed to inform monitoring requirements in National Pollutant Discharge Elimination System (NPDES) stormwater permits issued by the Washington State Department of Ecology (Ecology). The monitoring program is referred to as the Stormwater Action Monitoring (SAM).The overall focus of the work described in this report is to address one of the goals of SAM, which is to characterize the status, spatial extent, and quality of Puget Sound sediment chemicals in the nearshore urban areas. The nearshore urban areas are defined as areas parallel to established Urban Growth Areas (UGAs) using a spatially balanced probabilistic Generalized Random Tessellation Stratified (GRTS) sampling design. One of the benefits of the GRTS sampling design used for this study is that it allows one to efficiently extrapolate from a relatively small number of sampled nearshore sites to the entire nearshore shoreline within the 2011 defined UGA boundaries of Puget Sound. In addition to characterizing nearshore sediment chemical concentrations, this study also characterized the abundance of microplastics in the nearshore sediment.A total of 41 randomly selected sites were sampled throughout Puget Sound in summer and early autumn of 2016. All sampling sites were located at 6 feet below the Mean Lower Low Water line. The top 2–3 centimeters of sediment were collected using a boat-mounted, pre-cleaned stainless-steel box corer. All chemical samples were sieved to 2 millimeters and placed in appropriate containers for chemical analysis for PCBs, PBDEs, PAHs, phthalates, metals, total organic carbon, and grain size. Pre-sieved sediment samples were stored in glass containers for microplastic analysis. Nearshore sediment chemical concentrations were summarized using numerous statistical approaches to examine the minimum, mean, and maximum concentrations for each of the compounds analyzed and to compare the results to criteria and other nearshore and marine sediment studies. The GRTS sampling design also allowed the authors to assess the percentage of the UGA nearshore environment that did not meet established standards or criteria for each chemical analyzed. Additionally, regression and machine learning statistical analyses were used to examine relations between measured chemical concentrations, and land cover and geologic features at multiple scales within the watersheds adjacent to sampling sites. The influence of marine hydrodynamic factors on nearshore sediment chemical concentrations was statistically evaluated with nonparametric methods by assigning each sampling site to one of five nearshore drift cell types based on its location. The Puget Sound shoreline can be divided into segments, referred to as drift cells, based on the movement of sediment along the shore by waves. Each drift cell type has a unique influence on nearshore sediment transport.The nearshore sediment chemical concentrations for organics and metals generally were low, and in most cases less than Washington State criteria. The concentrations of some PAHs were greater than the criteria, but these exceedances were limited to one or two sites. The results of the probabilistic study design determined that, for the PAHs examined, 96 percent or more of the 1,344 km of shoreline represented by this study had concentrations less than any established criteria. For the remaining organics (PCBs and PBDEs), the probabilistic study design indicates that more than 98 percent of shoreline examined had concentrations less than criteria or proposed standards. For the metals, the results of the study indicate that 100 percent of the nearshore sediment had concentrations less than the criteria. The relations between sediment organic and metal concentrations, and adjacent watershed land cover and the particle size of the samples, were determined to be weakly related. Although weakly related, the particle size of the sediment in a sample typically explained more of the variation in metal concentrations than organics. While the measured watershed attributes adjacent to the sampling sites and sediment size of the samples were weakly related to chemical concentrations, they were significantly related to unique drift cells along the shoreline of Puget Sound known as drift cells. Each drift cell represents a long-term directional transport of sediment from its source to its depositional zone. Sediment chemical concentrations were significantly higher in drift cells with limited sediment movement compared to those with higher sediment transport energy.Microplastics in the nearshore sediment ranged from 0.02 to 0.65 pieces per gram of sediment, with a mean of 0.19 pieces per gram of sediment, and were dominated by small fibers (355–1,000 micrometers). Like chemical concentrations, microplastics concentrations in the nearshore sediment were poorly related to watershed land cover. Although not significantly different, microplastics concentrations generally were higher in the low energy drift cells compared to the high energy drift cells.The results of this study provide a statistically valid status assessment of current nearshore sediment chemical conditions throughout Puget Sound in those areas adjacent to defined UGAs. In addition to the study findings of relatively low concentrations of PCBs, PBDEs, PAHs, phthalates, and metals, the study design provides a statistically valid tool for evaluating changes in these compounds over time if future nearshore sediment assessments are done. Furthermore, the assessment of microplastic abundance represents the first study of its kind that can be used as a benchmark for future evaluations. The results of this study will help inform Ecology in the implementation of monitoring requirements as part of its NPDES stormwater permitting process.

Mississippi Sound Remote Sensing Study

NASA Technical Reports Server (NTRS)

Atwell, B. H.

1973-01-01

The Mississippi Sound Remote Sensing Study was initiated as part of the research program of the NASA Earth Resources Laboratory. The objective of this study is development of remote sensing techniques to study near-shore marine waters. Included within this general objective are the following: (1) evaluate existing techniques and instruments used for remote measurement of parameters of interest within these waters; (2) develop methods for interpretation of state-of-the-art remote sensing data which are most meaningful to an understanding of processes taking place within near-shore waters; (3) define hardware development requirements and/or system specifications; (4) develop a system combining data from remote and surface measurements which will most efficiently assess conditions in near-shore waters; (5) conduct projects in coordination with appropriate operating agencies to demonstrate applicability of this research to environmental and economic problems.

USGS capabilities for interdisciplinary investigations in coastal and nearshore ecosystems of the Great Lakes

USGS Publications Warehouse

Myers, Donna N.

2002-01-01

People choose to reside, work, and vacation in coastal areas of the Great Lakes because of the lakes' scenic beauty and their historic and cultural features. Great Lakes nearshore areas also constitute a valuable economic resource. Two million anglers added \\$1 billion to the region's economy in 1996. More than 300 million tons of goods were transported out of major Great Lakes ports at a value of \\$3 billion in 1996. A 1998 survey of Lake Erie beaches estimated contributions of $5 million per year to each local economy with a public beach. More than 70 million people yearly visit national, state and provincial parks in the Great Lakes area. Uncontrolled land development, recreational development, invasive species, climate change, water availability, and water-level changes and fluctuations lead a long list of current and potential issues in coastal and nearshore areas. To be effectively addressed, these complex issues require an interdisciplinary approach.

50 CFR 226.223 - Critical habitat for the Northwest Atlantic Ocean Distinct Population Segment of the loggerhead...

Code of Federal Regulations, 2014 CFR

2014-10-01

...) LOGG-N-15—Northern Boundary of River to Sea Preserve at Marineland to Granada Blvd., Flagler and... unit are nearshore areas from the north boundary of River to Sea Preserve at Marineland to Granada...

A Nested Nearshore Nutrient Model (N&Sup3;M) for Nearshore Condition Assessment and Management

EPA Science Inventory

Nearshore conditions drive phenomena like harmful algal blooms (HABs), and the nearshore and coastal margin are the parts of the Great Lakes most used by humans. To assess conditions, optimize monitoring, and evaluate management options, a model of nearshore nutrient transport an...

Nonlinear Mechanisms for the Generation of Nearshore Wave Phenomena.

DTIC Science & Technology

1988-04-01

Kadomtsev - Petviashvili equation . Numerical solutions of this equation indicate that steady state is reached only if dispersion is negative; otherwise...leads to a forced Kadomtsev - Petviashvili equation . Numerical solutions of this equation indicate that steady state is reached only if dispersion is

U.S. Geological Survey (USGS) Western Region: Alaska Coastal and Ocean Science

USGS Publications Warehouse

Holland-Bartels, Leslie

2009-01-01

The U.S. Geological Survey (USGS), a bureau of the Department of the Interior (DOI), is the Nation's largest water, earth, and biological science and mapping agency. The bureau's science strategy 'Facing Tomorrow's Challenges - U.S. Geological Survey Science in the Decade 2007-2017' describes the USGS vision for its science in six integrated areas of societal concern: Understanding Ecosystems and Predicting Ecosystem Change; Climate Variability and Change; Energy and Minerals; Hazards, Risk, and Resilience; Environment and Wildlife in Human Health; and Water Census of the United States. USGS has three Regions that encompass nine geographic Areas. This fact sheet describes examples of USGS science conducted in coastal, nearshore terrestrial, and ocean environments in the Alaska Area.

Coupling urban growth scenarios with nearshore biophysical change models to inform coastal restoration planning in Puget Sound, Washington

NASA Astrophysics Data System (ADS)

Byrd, K. B.; Kreitler, J.; Labiosa, W.

2010-12-01

A scenario represents an account of a plausible future given logical assumptions about how conditions change over discrete bounds of space and time. Development of multiple scenarios provides a means to identify alternative directions of urban growth that account for a range of uncertainty in human behavior. Interactions between human and natural processes may be studied by coupling urban growth scenario outputs with biophysical change models; if growth scenarios encompass a sufficient range of alternative futures, scenario assumptions serve to constrain the uncertainty of biophysical models. Spatially explicit urban growth models (map-based) produce output such as distributions and densities of residential or commercial development in a GIS format that can serve as input to other models. Successful fusion of growth model outputs with other model inputs requires that both models strategically address questions of interest, incorporate ecological feedbacks, and minimize error. The U.S. Geological Survey (USGS) Puget Sound Ecosystem Portfolio Model (PSEPM) is a decision-support tool that supports land use and restoration planning in Puget Sound, Washington, a 35,500 sq. km region. The PSEPM couples future scenarios of urban growth with statistical, process-based and rule-based models of nearshore biophysical changes and ecosystem services. By using a multi-criteria approach, the PSEPM identifies cross-system and cumulative threats to the nearshore environment plus opportunities for conservation and restoration. Sub-models that predict changes in nearshore biophysical condition were developed and existing models were integrated to evaluate three growth scenarios: 1) Status Quo, 2) Managed Growth, and 3) Unconstrained Growth. These decadal scenarios were developed and projected out to 2060 at Oregon State University using the GIS-based ENVISION model. Given land management decisions and policies under each growth scenario, the sub-models predicted changes in 1) fecal coliform in shellfish growing areas, 2) sediment supply to beaches, 3) State beach recreational visits, 4) eelgrass habitat suitability, 5) forage fish habitat suitability, and 6) nutrient loadings. In some cases thousands of shoreline units were evaluated with multiple predictive models, creating a need for streamlined and consistent database development and data processing. Model development over multiple disciplines demonstrated the challenge of merging data types from multiple sources that were inconsistent in spatial and temporal resolution, classification schemes, and topology. Misalignment of data in space and time created potential for error and misinterpretation of results. This effort revealed that the fusion of growth scenarios and biophysical models requires an up-front iterative adjustment of both scenarios and models so that growth model outputs provide the needed input data in the correct format. Successful design of data flow across models that includes feedbacks between human and ecological systems was found to enhance the use of the final data product for decision making.

Great Lakes Nearshore Assessment: What Would Goldilocks Do?

EPA Science Inventory

Concerns with the nearshore water quality of the Great Lakes, such as excessive eutrophication and harmful algal blooms, called for establishing a nearshore monitoring program to gain a better understanding of the watershed-nearshore link. This is challenging, as sporadic runoff ...

Estimating nearshore coral reef-associated fisheries production from the main Hawaiian Islands.

PubMed

McCoy, Kaylyn S; Williams, Ivor D; Friedlander, Alan M; Ma, Hongguang; Teneva, Lida; Kittinger, John N

2018-01-01

Currently, information on nearshore reef-associated fisheries is frequently disparate or incomplete, creating a challenge for effective management. This study utilized an existing non-commercial fishery dataset from Hawai'i, covering the period 2004-13, to estimate a variety of fundamental fishery parameters, including participation, effort, gear use, and catch per unit effort. We then used those data to reconstruct total catches per island. Non-commercial fisheries in this case comprise recreational, subsistence, and cultural harvest, which may be exchanged, but are not sold. By combining those data with reported commercial catch data, we estimated annual catch of nearshore reef-associated fisheries in the main Hawaiian Islands over the study period to be 1,167,758 ± 43,059 kg year-1 (mean ± standard error). Average annual commercial reef fish catch over the same time period-184,911 kg year-1-was 16% of the total catch, but that proportion varied greatly among islands, ranging from 23% on O'ahu to 5% on Moloka'i. These results emphasize the importance of reef fishing in Hawai'i for reasons beyond commerce, such as food security and cultural practice, and highlight the large differences in fishing practices across the Hawaiian Islands.

Evaluation of rockfish conservation area networks in the United States and Canada relative to the dispersal distance for black rockfish (Sebastes melanops)

PubMed Central

Lotterhos, Katie E; Dick, Stefan J; Haggarty, Dana R

2014-01-01

Marine reserves networks are implemented as a way to mitigate the impact of fishing on marine ecosystems. Theory suggests that a reserve network will function synergistically when connected by dispersal, but the scale of dispersal is often unknown. On the Pacific coast of the United States and Canada, both countries have recently implemented a number of rockfish conservation areas (RCAs) to protect exploited rockfish species, but no study has evaluated the connectivity within networks in each country or between the two countries. We used isolation-by-distance theory to estimate the scale of dispersal from microsatellite data in the black rockfish, Sebastes melanops, and compared this estimate with the distance between RCAs that would protect this species. Within each country, we found that the distance between RCAs was generally within the confidence intervals of mean dispersal per generation. The distance between these two RCA networks, however, was greater than the average dispersal per generation. The data were also consistent with a genetic break between southern Oregon and central Oregon. We discuss whether additional nearshore RCAs in southern Oregon and Washington would help promote connectivity between RCA's for shallow-water rockfishes. PMID:24567745

Watershed Influences on Nearshore Waters Across the Entire US Great Lakes Coastal Region

EPA Science Inventory

We have combined three elements of observation to enable a comprehensive characterization of the Great Lakes nearshore that links nearshore conditions with their adjacent coastal watersheds. The three elements are: 1) a shore-parallel, high-resolution survey of the nearshore usin...

Nearshore Phytoplankton Production on the Louisiana Continental Shelf

NASA Astrophysics Data System (ADS)

Fung, M.; Lehrter, J. C.

2017-12-01

Net heterotrophy has been observed across much of the Louisiana continental shelf (LCS) where hypoxic conditions occur. Recent studies suggest that cross-shelf transport of nearshore organic matter derived from phytoplankton production subsidizes this heterotrophy. To investigate this theory, we conducted two cruises in spring and summer of 2017 to assess the spatial and temporal patterns of primary production (PP) and respiration (R). We focused on nearshore waters across the area of the shelf where hypoxia is most frequently observed. Overall, PP rates were highest (median = 35 mmol O2 m-3 d-1) in nearshore surface waters (sites with <15 m depth and riverine plume locations), but temporal and spatial differences were seen in both the magnitude of PP and R. Nearshore waters in spring had the highest production rates (median = 52.3 mmol O2 m-3 d-1) and were an order of magnitude greater than production in offshore waters (>15 m depth), while summer production rates in the nearshore and offshore areas were comparable. Similarly, spring nearshore respiration rates (11.2 mmol O2 m-3 d-1) were an order of magnitude larger than offshore, and summer respiration rates in the nearshore and offshore areas were comparable. P/R was greatest nearshore in the spring (4.7) and lowest offshore in the summer (0.9). These results suggest that nearshore production is potentially a significant source of organic matter for the observed heterotrophy over most of the LCS, supporting the theory that shelf-wide hypoxia may be largely driven by nearshore production.

Beach and dune building processes: Linking nearshore to backshore and events to decades

NASA Astrophysics Data System (ADS)

Ruggiero, P.; Cohn, N.; Hacker, S.; Moore, L. J.; Duran Vinent, O.; de Vries, S.

2016-12-01

Due to the wide range of complex processes in the active coastal zone, individual studies have tended to focus on specific time scales (e.g., event-scale erosion) and/or specific morphological units, (e.g., the nearshore bar zone). As a result, the wet and dry portions of the beach have typically been studied independently. In nature, however, the nearshore and the backshore are highly interdependent and understanding the linkages between these units is critical to characterizing coastal evolution. For example, during periods of intense storm conditions (e.g., major El Niños on the U.S. West Coast), elevated water levels and large waves commonly lead to the scarping, or even destruction, of wind formed dunes. Given that dunes act as a form of green infrastructure and are a major asset to the coastal zone, it is critical to be able to forecast backshore evolution. Existing models for backshore recovery, however, are typically based on local historical trends rather than a mechanistic understanding including onshore sediment transport, dune growth, and the role of ecomorphodynamic feedbacks. Therefore, most likely as a result of the historical academic separation of wave and wind driven processes, geomorphology and ecology, and short- and long-term processes, our understanding of beach and dune building is still in its infancy. Here we describe SEDEX2, the Sandbar-aEolian-Dune EXchange Experiment, a comprehensive summer 2016 field campaign in which measurements of waves, currents, wind, dune ecology, subaqueous and aeolian sediment transport, and subsequent morphological changes were collected along the Long Beach Peninsula, WA. The data collected during the six-week experiment are contextualized by nearly two decades of focused research on the seasonal-centennial scale evolution of this rapidly prograding system. The findings of this study, actively bridging across disciplines, morphometric units, and temporal scales are informing conceptual and numerical models of beach-dune interaction and helping to improve management of vital backshore resources.

Coastal and lower Elwha River, Washington, prior to dam removal--history, status, and defining characteristics: Chapter 1 in Coastal habitats of the Elwha River, Washington--biological and physical patterns and processes prior to dam removal

USGS Publications Warehouse

Duda, Jeffrey J.; Warrick, Jonathan A.; Magirl, Christopher S.; Duda, Jeffrey J.; Warrick, Jonathan A.; Magirl, Christopher S.

2011-01-01

Characterizing the physical and biological characteristics of the lower Elwha River, its estuary, and adjacent nearshore habitats prior to dam removal is essential to monitor changes to these areas during and following the historic dam-removal project set to begin in September 2011. Based on the size of the two hydroelectric projects and the amount of sediment that will be released, the Elwha River in Washington State will be home to the largest river restoration through dam removal attempted in the United States. Built in 1912 and 1927, respectively, the Elwha and Glines Canyon Dams have altered key physical and biological characteristics of the Elwha River. Once abundant salmon populations, consisting of all five species of Pacific salmon, are restricted to the lower 7.8 river kilometers downstream of Elwha Dam and are currently in low numbers. Dam removal will reopen access to more than 140 km of mainstem, flood plain, and tributary habitat, most of which is protected within Olympic National Park. The high capture rate of river-borne sediments by the two reservoirs has changed the geomorphology of the riverbed downstream of the dams. Mobilization and downstream transport of these accumulated reservoir sediments during and following dam removal will significantly change downstream river reaches, the estuary complex, and the nearshore environment. To introduce the more detailed studies that follow in this report, we summarize many of the key aspects of the Elwha River ecosystem including a regional and historical context for this unprecedented project.

Tectonic controls on nearshore sediment accumulation and submarine canyon morphology offshore La Jolla, Southern California

USGS Publications Warehouse

Le Dantec, Nicolas; Hogarth, Leah J.; Driscoll, Neal W.; Babcock, Jeffrey M.; Barnhardt, Walter A.; Schwab, William C.

2010-01-01

CHIRP seismic and swath bathymetry data acquired offshore La Jolla, California provide an unprecedented three-dimensional view of the La Jolla and Scripps submarine canyons. Shore-parallel patterns of tectonic deformation appear to control nearshore sediment thickness and distribution around the canyons. These shore-parallel patterns allow the impact of local tectonic deformation to be separated from the influence of eustatic sea-level fluctuations. Based on stratal geometry and acoustic character, we identify a prominent angular unconformity inferred to be the transgressive surface and three sedimentary sequences: an acoustically laminated estuarine unit deposited during early transgression, an infilling or “healing-phase” unit formed during the transgression, and an upper transparent unit. Beneath the transgressive surface, steeply dipping reflectors with several dip reversals record faulting and folding along the La Jolla margin. Scripps Canyon is located at the crest of an antiform, where the rocks are fractured and more susceptible to erosion. La Jolla Canyon is located along the northern strand of the Rose Canyon Fault Zone, which separates Cretaceous lithified rocks to the south from poorly cemented Eocene sands and gravels to the north. Isopach and structure contour maps of the three sedimentary units reveal how their thicknesses and spatial distributions relate to regional tectonic deformation. For example, the estuarine unit is predominantly deposited along the edges of the canyons in paleotopographic lows that may have been inlets along barrier beaches during the Holocene sea-level rise. The distribution of the infilling unit is controlled by pre-existing relief that records tectonic deformation and erosional processes. The thickness and distribution of the upper transparent unit are controlled by long-wavelength, tectonically induced relief on the transgressive surface and hydrodynamics.

Nearshore Birds in Puget Sound

DTIC Science & Technology

2006-05-01

Published by Seattle District, U.S. Army Corps of Engineers, Seattle, Washington. Kriete, B. 2007. Orcas in Puget Sound . Puget Sound Near- shore...Technical Report 2006-05 Puget Sound Nearshore Partnership I Nearshore Birds in Puget Sound Prepared in...support of the Puget Sound Nearshore Partnership Joseph B. Buchanan Washington Department of Fish and Wildlife Technical Report 2006-05 ii

Invasive lionfish reduce native fish abundance on a regional scale

NASA Astrophysics Data System (ADS)

Ballew, Nicholas G.; Bacheler, Nathan M.; Kellison, G. Todd; Schueller, Amy M.

2016-08-01

Invasive lionfish pose an unprecedented threat to biodiversity and fisheries throughout Atlantic waters off of the southeastern United States, the Caribbean, and the Gulf of Mexico. Here, we employ a spatially replicated Before-After-Control-Impact analysis with temporal pairing to quantify for the first time the impact of the lionfish invasion on native fish abundance across a broad regional scale and over the entire duration of the lionfish invasion (1990-2014). Our results suggest that 1) lionfish-impacted areas off of the southeastern United States are most prevalent off-shore near the continental shelf-break but are also common near-shore and 2) in impacted areas, lionfish have reduced tomtate (a native forage fish) abundance by 45% since the invasion began. Tomtate served as a model native fish species in our analysis, and as such, it is likely that the lionfish invasion has had similar impacts on other species, some of which may be of economic importance. Barring the development of a control strategy that reverses the lionfish invasion, the abundance of lionfish in the Atlantic, Caribbean, and Gulf of Mexico will likely remain at or above current levels. Consequently, the effect of lionfish on native fish abundance will likely continue for the foreseeable future.

Invasive lionfish reduce native fish abundance on a regional scale.

PubMed

Ballew, Nicholas G; Bacheler, Nathan M; Kellison, G Todd; Schueller, Amy M

2016-08-31

Invasive lionfish pose an unprecedented threat to biodiversity and fisheries throughout Atlantic waters off of the southeastern United States, the Caribbean, and the Gulf of Mexico. Here, we employ a spatially replicated Before-After-Control-Impact analysis with temporal pairing to quantify for the first time the impact of the lionfish invasion on native fish abundance across a broad regional scale and over the entire duration of the lionfish invasion (1990-2014). Our results suggest that 1) lionfish-impacted areas off of the southeastern United States are most prevalent off-shore near the continental shelf-break but are also common near-shore and 2) in impacted areas, lionfish have reduced tomtate (a native forage fish) abundance by 45% since the invasion began. Tomtate served as a model native fish species in our analysis, and as such, it is likely that the lionfish invasion has had similar impacts on other species, some of which may be of economic importance. Barring the development of a control strategy that reverses the lionfish invasion, the abundance of lionfish in the Atlantic, Caribbean, and Gulf of Mexico will likely remain at or above current levels. Consequently, the effect of lionfish on native fish abundance will likely continue for the foreseeable future.

Invasive lionfish reduce native fish abundance on a regional scale

PubMed Central

Ballew, Nicholas G.; Bacheler, Nathan M.; Kellison, G. Todd; Schueller, Amy M.

2016-01-01

Invasive lionfish pose an unprecedented threat to biodiversity and fisheries throughout Atlantic waters off of the southeastern United States, the Caribbean, and the Gulf of Mexico. Here, we employ a spatially replicated Before-After-Control-Impact analysis with temporal pairing to quantify for the first time the impact of the lionfish invasion on native fish abundance across a broad regional scale and over the entire duration of the lionfish invasion (1990–2014). Our results suggest that 1) lionfish-impacted areas off of the southeastern United States are most prevalent off-shore near the continental shelf-break but are also common near-shore and 2) in impacted areas, lionfish have reduced tomtate (a native forage fish) abundance by 45% since the invasion began. Tomtate served as a model native fish species in our analysis, and as such, it is likely that the lionfish invasion has had similar impacts on other species, some of which may be of economic importance. Barring the development of a control strategy that reverses the lionfish invasion, the abundance of lionfish in the Atlantic, Caribbean, and Gulf of Mexico will likely remain at or above current levels. Consequently, the effect of lionfish on native fish abundance will likely continue for the foreseeable future. PMID:27578096

The Influence of Submarine Groundwater Discharge on Nearshore Marine Dissolved Organic Carbon Reactivity, Concentration Dynamics, and Offshore Export

NASA Astrophysics Data System (ADS)

Goodridge, B.

2017-12-01

Dissolved organic carbon (DOC) is the largest pool of reduced carbon in the oceans, with a reservoir equivalent to atmospheric CO2. In nearshore marine regions, DOC sources include primary production, terrestrial DOC delivered by river discharge, and/or terrestrial and marine DOC delivered via submarine groundwater discharge (SGD). While the importance of SGD to coastal carbon cycling has been implicated, the actual influence of this process on nearshore carbon dynamics and offshore export has not been explicitly identified. This study, conducted at a predominantly marine-influenced intertidal beach-nearshore ocean system along the Santa Barbara, California coastline, aimed to address this knowledge gap. I coupled dark, temperature-controlled laboratory incubations, radioisotopic (Rn-222) SGD estimates, and a DOC box model to identify the influence of pore water mixing with seawater on nearshore DOC reactivity, concentration dynamics, and offshore export. Even with a relatively low volumetric contribution, SGD pore water mixing altered nearshore DOC reactivity, and elevated the nearshore DOC concentration by 0.9 to 5.6 µmol L-1 over nearshore seawater residence times ranging from 1 to 6 days. These elevated DOC concentrations were equivalent to 1.2 to 7.5% of the mean offshore DOC concentration taken during the summer months in the Santa Barbara Channel, when the coastal water column is highly thermally stratified. Despite the challenge of assessing carbon dynamics in physically and biogeochemically complex nearshore marine regions, this study demonstrates the need for future investigations to assess and account for SGD as a non-trivial component of coastal marine carbon cycles.

Nearshore Survey System Evaluation

DTIC Science & Technology

2017-12-01

ER D C/ CH L TR -1 7- 19 Coastal Field Data Collection Program Nearshore Survey System Evaluation Co as ta l a nd H yd ra ul ic s La...Collection Program ERDC/CHL TR-17-19 December 2017 Nearshore Survey System Evaluation Michael F. Forte, William A. Birkemeier, and J. Robert Mitchell...No. 462585 ERDC/CHL TR-17-19 ii Abstract This report evaluates the accuracy of two systems for surveying the beach and nearshore zone. The 10

Sources of fecal indicator bacteria to groundwater, Malibu Lagoon and the near-shore ocean, Malibu, California, USA

USGS Publications Warehouse

Izbicki, John A.; Swarzenski, Peter W.; Burton, Carmen A.; Van De Werfhorst, Laurie; Holden, Patricia A.; Dubinsky, Eric A.

2012-01-01

Onsite wastewater treatment systems (OWTS) used to treat residential and commercial sewage near Malibu, California have been implicated as a possible source of fecal indicator bacteria (FIB) to Malibu Lagoon and the near-shore ocean. For this to occur, treated wastewater must first move through groundwater before discharging to the Lagoon or ocean. In July 2009 and April 2010, δ18O and δD data showed that some samples from water-table wells contained as much as 70% wastewater; at that time FIB concentrations in those samples were generally less than the detection limit of 1 Most Probable Number (MPN) per 100 milliliters (mL). In contrast, Malibu Lagoon had total coliform, Escherichia coli, and enterococci concentrations as high as 650,000, 130,000, and 5,500 MPN per 100 mL, respectively, and as many as 12% of samples from nearby ocean beaches exceeded the U.S. Environmental Protection Agency single sample enterococci standard for marine recreational water of 104 MPN per 100 mL. Human-associated Bacteroidales, an indicator of human-fecal contamination, were not detected in water from wells, Malibu Lagoon, or the near-shore ocean. Similarly, microarray (PhyloChip) data show Bacteroidales and Fimicutes Operational Taxanomic Units (OTUs) present in OWTS were largely absent in groundwater; in contrast, 50% of Bacteroidales and Fimicutes OTUs present in the near-shore ocean were also present in gull feces. Terminal-Restriction Length Fragment Polymorphism (T-RFLP) and phospholipid fatty acid (PLFA) data showed that microbial communities in groundwater were different and less abundant than communities in OWTS, Malibu Lagoon, or the near-shore ocean. However, organic compounds indicative of wastewater (such as fecal sterols, bisphenol-A and cosmetics) were present in groundwater having a high percentage of wastewater and were present in groundwater discharging to the ocean. FIB in the near-shore ocean varied with tides, ocean swells, and waves. Movement of water from Malibu Lagoon through the sand berm at the mouth of the Lagoon contributed FIB to the adjacent beach at low tide. Similar increases in FIB concentrations did not occur at beaches adjacent to unsewered residential development, although wastewater indicator compounds and radon-222 (indicative of groundwater discharge) were present. High FIB concentrations at high tide were not related to groundwater discharge, but may be related to FIB associated with debris accumulated along the high-tide line.

Mapping and Mitigating the International Rip Current Health Hazard

NASA Astrophysics Data System (ADS)

Trimble, S. M.; Houser, C.

2016-12-01

Rip currents are concentrated seaward flows of water originating in the surf zones of beaches. Rips cause hundreds of international drownings each year. Calculating exact numbers is barred by logistical difficulties in obtaining accurate incident reports, but annual rip current fatalities are estimated at 100, 53 and 21 in the United States (US), Costa Rica, and Australia respectively. Notably, Australia's lifeguards rescue 17,600 swimmers from rips each year. This project addresses the geophysical, social, and systematic causes of fatalities in hopes of decreasing the global number of rip-related deaths. We demonstrate a novel method for mapping bathymetry in the surf zone (20m deep or less), specifically within rip channels (topographic low spots in the nearshore that result from feedback amongst waves, substrate, and antecedent bathymetry). We calculate bathymetry using 8-band multispectral imagery from the Digital Globe WorldView2 (WV2) satellite and field measurements of depth, generating maps of the changing nearshore at two embayed, rip-prone beaches: Playa Cocles, Costa Rica, and Bondi Beach, Australia. WV2 has a 1.1 day pass-over rate with 1.84m ground pixel resolution of 8 bands, including `yellow' (585-625 nm) and `coastal blue' (400-450 nm). Methods are tested for consistency amongst dates and locations. Previous research shows drownings result from a combination of the physical environment with personal and group behaviors; for this reason we build on rip-detection by evaluating tourists' and locals' knowledge and understanding of their beach's rip behavior. By combining the geomorphologic maps developed from WV2 with interview data, we evaluate how the physical environment dictates the exposure of certain swimmers. Controls include rip channel location, beach access points, and environmental factors favored by swimmers. The project serves as an evaluation of the landscape's creation of a physical feature that becomes a hazard when vulnerable humans swim into it. Results are meant to inform policy makers so that they may implement the methods: developing frequent nearshore maps to observe rip channel behavior, designing beach access controls informed by morphology, posting informative signs in ideal locations, and funding lifeguard programs.

2013 status of the Lake Ontario lower trophic levels

USGS Publications Warehouse

Holeck, Kristen T.; Rudstam, Lars G.; Hotaling, Christopher; McCullough, Russ D.; Lemon, Dave; Pearsall, Web; Lantry, Jana R.; Connerton, Michael J.; LaPan, Steve; Trometer, Betsy; Lantry, Brian F.; Walsh, Maureen; Weidel, Brian C.

2014-01-01

Phosphorus showed high variation across nearshore (10 m depth) sites but was more stable at offshore (20 m and deeper) stations. In June and July, sites at the mouth of the Niagara River and at Oak Orchard had high phosphorus concentrations (20 – 46 μg/L). Epilimnetic average April-Oct total phosphorus (TP) ranged between 6.9 and 19.9 μg/L in the nearshore and between 5.8 and 10.2 μg/L in the offshore. Average April-Oct soluble reactive phosphorus (SRP) ranged from 0.9 to 7.3 μg/L in the nearshore and 0.8 to 1.4 μg/L in the offshore. TP and SRP were significantly higher in the nearshore than in the offshore.Spring TP has declined in the longer data series (since 1981), but not since 1995. It averaged 8.4 μg/L in the nearshore and 5.0 μg/L in the offshore in 2013—below the 10 μg/L target set by the Great Lakes Water Quality Agreement of 1978 for offshore waters of Lake Ontario.Offshore summer chlorophyll-a declined significantly in both the short- (1995-2013) and long-term (1981-2013) time series at a rate of 3-4% per year. Nearshore chlorophyll-a increased after 2003 but then declined again after 2009. Epilimnetic chlorophyll-aaveraged between 0.5 and 1.3 μg/L across sites with no difference between nearshore and offshore habitats. Average seasonal Secchi disk depth ranged from 4.5 m to 10.6 m and was higher in the offshore (average 8.1 m) than nearshore stations (6.3 m). These values are indicative of oligotrophic conditions in both habitats.In 2013, Apr/May - Oct epilimnetic zooplankton size and total biomass were significantly higher in the offshore than the nearshore. However, with the exception of Limnocalanus (higher in offshore), there were no differences between habitats for any of the zooplankton groups.Most of the zooplankton biomass was in the metalimnion and hypolimnion during the day in 2013. Between 65 and 98% of zooplankton biomass was found below the thermocline throughout the year.The predatory cladoceran Cercopagis continued to be abundant in the summer, peaking at ~7 mg/m3in the offshore. Bythotrephes peaked in October (~0.7 mg/m3), but Bythotrephes biomass was at its lowest biomass in both offshore and nearshore stations since 2005.Summer nearshore zooplankton density and biomass have declined significantly since 1995 at rates of 9-10% per year. Nearshore epilimnetic zooplankton density and biomass have remained stable since 2005 at low levels relative to previous years.Summer offshore zooplankton density and biomass in the epilimnion of Lake Ontario have also declined since 1995 at rates of 10-14% per year, but those declines are marginally significant; density declined significantly in the long-term (since 1981) but has remained at a lower stable level since 2005.Bosminid and cyclopoid copepod biomass declined significantly in nearshore waters. The same pattern occurred in the offshore but declines were significant for bosminids and marginally significant for cyclopoid copepods. Daphnid biomass has also declined significantly in the nearshore.The decline in Daphnid biomass nearshore and Bythotrephes biomass offshore and nearshore is indicative of increased planktivory by alewife. Significant declines in Bosminid and cyclopoid copepod biomass is indicative of increased invertebrate predation by Cercopagis and Bythotrephes in recent years.

Variability within nearshore ecosystems of the Gulf of Alaska

USGS Publications Warehouse

Ballachey, Brenda E.; Bodkin, James L.; Coletti, Heather A.; Dean, Thomas A; Esler, Daniel N.; Esslinger, George G.; Iken, Katrin; Kloecker, Kimberly A.; Konar, Brenda; Lindeberg, Mandy; Monson, Daniel; Shepherd, Marnie; Weitzman, Ben P.

2015-01-01

Nearshore marine habitats, which represent the interface among air, land and sea, form a critical component of the Gulf of Alaska (GOA) ecosystem. As an interface, the nearshore facilitates transfer of water, nutrients and biota between terrestrial and oceanic systems, creating zones of high productivity. The nearshore provides a variety of ecosystem services, including (1) nursery grounds for a wide variety of marine invertebrates and fishes (e.g., crabs, salmon, and herring), (2) nesting and pupping habitats for many pelagic marine predators (e.g., sea bird nesting colonies and pinniped rookeries), (3) important feeding habitats for high trophic level pelagic predators (e.g., killer whales), (4) habitat for resident nearshore species (including sea otters, harbor seals, shorebirds, sea ducks, nearshore fishes, and marine invertebrates), many of which are important sources of commercial and subsistence harvests, and (5) recreational, commercial and subsistence opportunities for human populations (Figure 1-1). The canopy forming kelps and eel grass beds found in the nearshore provide primary production and structure to nursery habitats, and also can dissipate wave energy thus reducing coastal erosion, and serve as a carbon “sink” capable of storing substantial amounts of atmospheric CO2 (Wilmers et al. 2012).

Nearshore Sea Clutter Measurements from a Fixed Platform

DTIC Science & Technology

2012-04-01

Water (MLL W) datum. 7. GPS Two differential GPS units, Magellan ProMark 3.0, were utilized to determine precise differences in position between the...8 Figure 8. (a) Trihedral configuration on the small boat and position of the GPS and IMU sensors. (b) Profile view of...SIO Miniature Directional Wave Buoys The Scripps Institution of Oceanography designs and manufactures GPS -based miniature directional wave buoys

Lake Michigan nearshore: How modeling scenarios can improve dialog between modelers and ecologists

EPA Science Inventory

The nearshore of Lake Michigan, similarly to the other Great Lakes, experiences environmental concerns due to excessive eutrophication. Assessing the nearshore is challenging because fluctuating nutrient loads, and ever-changing currents cause this area to exhibit large spatial a...

Extension of 239+240Pu sediment geochronology to coarse-grained marine sediments

USGS Publications Warehouse

Kuehl, Steven A.; Ketterer, Michael E.; Miselis, Jennifer L.

2012-01-01

Sediment geochronology of coastal sedimentary environments dominated by sand has been extremely limited because concentrations of natural and bomb-fallout radionuclides are often below the limit of measurement using standard techniques. ICP-MS analyses of 239+240Pu from two sites representative of traditionally challenging (i.e., low concentration) environments provide a "proof of concept" and demonstrate a new application for bomb-fallout radiotracers in the study of sandy shelf-seabed dynamics. A kasten core from the New Zealand shelf in the Southern Hemisphere (low fallout), and a vibracore from the sandy nearshore of North Carolina (low particle surface area) both reveal measurable 239+240Pu activities at depth. In the case of the New Zealand site, independently verified steady-state sedimentation results in a 239+240Pu profile that mimics the expected atmospheric fallout. The depth profile of 239+240Pu in the North Carolina core is more uniform, indicating significant sediment resuspension, which would be expected in this energetic nearshore environment. This study, for the first time, demonstrates the utility of 239+240Pu in the study of sandy environments, significantly extending the application of bomb-fallout isotopes to coarse-grained sediments, which compose the majority of nearshore regions.

Large sand waves on the Atlantic Outer Continental Shelf around Wilmington Canyon, off Eastern United States

USGS Publications Warehouse

Knebel, H.J.; Folger, D.W.

1976-01-01

New seismic-reflection data show that large sand waves near the head of Wilmington Canyon on the Atlantic Outer Continental Shelf have a spacing of 100-650 m and a relief of 2-9 m. The bedforms trend northwest and are asymmetrical, the steeper slopes being toward the south or west. Vibracore sediments indicate that the waves apparently have formed on a substrate of relict nearshore sediments. Although the age of the original bedforms is unknown, the asymmetry is consistent with the dominant westerly to southerly drift in this area which has been determined by other methods; the asymmetry, therefore, is probably modern. Observations in the sand-wave area from a submersible during August 1975, revealed weak bottom currents, sediment bioturbation, unrippled microtopography, and lack of scour. Thus, the asymmetry may be maintained by periodic water motion, possibly associated with storms or perhaps with flow in the canyon head. ?? 1976.

USGS science for the Nation's changing coasts: shoreline change research

USGS Publications Warehouse

Hapke, Cheryl J.; Thieler, E. Robert

2011-01-01

The demands of increasing human population in the coastal zone create competition with coastal habitat preservation and with recreational and commercial uses of the coast and nearshore waters. As climate changes over the coming century, these problems facing coastal communities will likely worsen. Good management and policy decision-making require baseline information on the rates, trends, and scientific understanding of the processes of coastal change on a regional to national scale. To address this need, the U.S. Geological Survey (USGS) is engaged in a research project of national scope to measure, report, and interpret historical shoreline change along open-ocean coasts of the United States. One of the primary goals of this project is to understand shoreline change hazards using methods that are comparable from one area of the country to another and that will allow for future, repeatable analyses of shoreline movement, coastal erosion, and land loss.

Lake Ontario: Nearshore Conditions and Variability in Water Quality Parameters

EPA Science Inventory

Interest in recent years has increased regarding conditions in the nearshore of the Great Lakes. We conducted a high-resolution survey of the Lake Ontario nearshore along the 20 m contour using towed electronic instrumentation. The 720 km survey was conducted September 6-10, 20...

Lake Michigan: Nearshore variability and a nearshore-offshore distinction in water quality

EPA Science Inventory

We conducted a high-resolution survey of the Lake Michigan nearshore using towed electronic instrumentation and fixed station sampling (1049 km at the approximate 20-m depth contour and grab samples at 15 sites). The principal variability in the alongshore reach was generally re...

An Integrated Set of Observations to Link Conditions of Great Lakes Nearshore Waters to their Coastal Watersheds

EPA Science Inventory

We combine three elements for a comprehensive characterization that links nearshore conditions with coastal watershed disturbance metrics. The three elements are: 1) a shore-parallel, high-resolution nearshore survey using continuous in situ towed sensors; 2) a spatially-balanc...

Detecting Land-based Signals in the Near-shore Zone of Lake Erie During Summer 2009

EPA Science Inventory

We conducted two styles of nearshore surveys in Lake Erie during August to mid-September 2009. The first used a spatially-balanced probability survey (SBS) design to establish discrete stations within a GIS-defined target populationthe nearshore zone extending approximately 5 km...

Great Lakes nearshore-offshore: Distinct water quality regions

EPA Science Inventory

We compared water quality of nearshore regions in the Laurentian Great Lakes to water quality in offshore regions. Sample sites for the nearshore region were from the US EPA National Coastal Condition Assessment and based on a criteria or sample-frame of within the 30-m depth co...

Eelgrass habitat near Liberty Bay: Chapter 5

USGS Publications Warehouse

Dinicola, Richard S.; Takesue, Renee K.

2015-01-01

Seagrasses are a widespread type of marine flowering plants that grow in nearshore intertidal and subtidal zones. Seagrass beds are ecologically important because they affect physical, biological, and chemical characteristics of nearshore habitat, and they are sensitive to changes in coastal water quality (Stevenson and others, 1993; Koch, 2001; Martinez-Crego and others, 2008). Zostera marina, commonly known as eelgrass, is protected by a no-net-loss policy in Washington State where it may be used as spawning habitat by herring, a key prey species for salmon, seabirds, and marine mammals (Bargmann, 1998). Eelgrass forms broad meadows in shallow embayments or narrow fringes on open shorelines (Berry and others, 2003). Anthropogenic activities that increase turbidity, nutrient loading, and physical disturbance at the coast can result in dramatic seagrass decline (Ralph and others, 2006).

Coupling alongshore variations in wave energy to beach morphologic change using the SWAN wave model at Ocean Beach, San Francisco, CA

USGS Publications Warehouse

Eshleman, Jodi L.; Barnard, Patrick L.; Erikson, Li H.; Hanes, Daniel M.

2007-01-01

Coastal managers have faced increasing pressure to manage their resources wisely over the last century as a result of heightened development and changing environmental forcing. It is crucial to understand seasonal changes in beach volume and shape in order to identify areas vulnerable to accelerated erosion. Shepard (1950) was among the first to quantify seasonal beach cycles. Sonu and Van Beek (1971) and Wright et al. (1985) described commonly occurring beach states. Most studies utilize widest spaced 2-D cross shore profiles or shorelines extracted from aerial photographs (e.g. Winant et al. 1975; Aubrey, 1979, Aubrey and Ross, 1985; Larson and Kraus, 1994; Jimenez et al., 1977; Lacey and Peck, 1998; Guillen et al., 1999; Norcorss et al., 2002) to analyzed systematic changes in beach evolution. But with the exception of established field stations, such as Duck, NC (Birkemeier and Mason, 1984), ans Hazaki Oceanographical Research Station (HORS) in Japan (Katoh, 1997), there are very few beach change data sets with high temporal and spatial resolutions (e.g. Dail et al., 2000; Ruggiero et al., 2005; Yates et al., in press). Comprehensive sets of nearshore morphological data and local in situ measurements outside of these field stations are very rare and virtually non-existent high-energy coasts. Studied that have attempted to relate wave statistics to beach morphology change require some knowledge of the nearshore wave climate, and have had limited success using offshore measurement (Sonu and Van Beek, 1971; Dail et al., 2000). The primary objective of this study is to qualitatively compare spatially variable nearshore wave predictions to beach change measurements in order to understand the processes responsible for a persistent erosion 'hotspot' at Ocean Beach, San Francisco, CA. Local wave measurements are used to calibrate and validate a wave model that provides nearshore wave prediction along the beach. The model is run for thousands of binned offshore wave conditions to help isolate the effects of offshore wave direction and period on nearshore wave predictions. Alongshore varying average beach change statistics are computed at specific profile locations from topographic beach surveys and lidar data. The study area is located in the San Francisco Bight in central California. Ocean Beach is a seven kilometer long north-south trending sandy coastline located just south of the entrance to the San Francisco Bay Estuary (Figure 1). It contains an erosion hotspot in the southern part of the beach which has resulted in damage to local infrastructure and is the cause of continued concern. A wide range of field data collection and numerical modeling efforts have been focused here as part of the United States Geological Survey's (USGS) San Francisco Bight Coastal Processes Study, which began in October 2003 and represents the first comprehensive study of coastal processes at the mouth of San Francisco Bay. Ocean Beach is exposed to very strong tidal flows, with measured currents often in excess of 1 m/s at the north end of the beach. Current profiler measurements indicate that current magnitudes are greater in the northern portion of the beach, while wave energy is greater in the southern portion where erosion problems are greatest (Barnard et al., 2007). The sub-aerial beach volume fluctuates seasonally over a maximum envelope of 400,000 m3 for the seven kilometer stretch (Barnard et al, 2007). The wave climate in the region is dominated by an abundance of low frequency energy (greater than 20 s period) and prevailing northwest incident wave angles. The application of a wave model to the region is further complicated by the presence of the Farallon Islands 40 kilometers west, and a massive ebb tidal delta at the mouth of San Francisco Bay (~150 km2), which creates complicated refraction patterns as wave energy moves from offshore Ocean Beach; however the cost and threat of the energetic nearshore environment have limited the temporal and spatial resolution of these measurements. Applying numerical models to predict wave and current patterns along the beach can help supplement the filed data that exists and provide opportunities to make prediction about the impacts of changing environmental forcing.

Millennial-scale climate variability during the Last Glacial period in the tropical Andes

NASA Astrophysics Data System (ADS)

Fritz, S. C.; Baker, P. A.; Ekdahl, E.; Seltzer, G. O.; Stevens, L. R.

2010-04-01

Millennial-scale climate variation during the Last Glacial period is evident in many locations worldwide, but it is unclear if such variation occurred in the interior of tropical South America, and, if so, how the low-latitude variation was related to its high-latitude counterpart. A high-resolution record, derived from the deep drilling of sediments on the floor of Lake Titicaca in the southern tropical Andes, is presented that shows clear evidence of millennial-scale climate variation between ˜60 and 20 ka BP. This variation is manifested by alternations of two interbedded sedimentary units. The two units have distinctive sedimentary, geochemical, and paleobiotic properties that are controlled by the relative abundance of terrigenous or nearshore components versus pelagic components. The sediments of more terrigenous or nearshore nature likely were deposited during regionally wetter climates when river transport of water and sediment was higher, whereas the sediments of more pelagic character were deposited during somewhat drier climates regionally. The majority of the wet periods inferred from the Lake Titicaca sediment record are correlated with the cold events in the Greenland ice cores and North Atlantic sediment cores, indicating that increased intensity of the South American summer monsoon was part of near-global scale climate excursions.

Customizing WRF-Hydro for the Laurentian Great Lakes Basin

NASA Astrophysics Data System (ADS)

Gronewold, A.; Pei, L.; Gochis, D.; Mason, L.; Sampson, K. M.; Dugger, A. L.; Read, L.; McCreight, J. L.; Xiao, C.; Lofgren, B. M.; Anderson, E. J.; Chu, P. Y.

2017-12-01

To advance the state of the art in regional hydrological forecasting, and to align with operational deployment of the National Water Model, a team of scientists has been customizing WRF-Hydro (the Weather Research and Forecasting model - Hydrological modeling extension package) to the entirety (including binational land and lake surfaces) of the Laurentian Great Lakes basin. Objectives of this customization project include opererational simulation and forecasting of the Great Lakes water balance and, in the short-term, research-oriented insights into modeling one- and two-way coupled lake-atmosphere and near-shore processes. Initial steps in this project have focused on overcoming inconsistencies in land surface hydrographic datasets between the United States and Canada. Improvements in the model's current representation of lake physics and stream routing are also critical components of this effort. Here, we present an update on the status of this project, including a synthesis of offline tests with WRF-Hydro based on the newly developed Great Lakes hydrographic data, and an assessment of the model's ability to simulate seasonal and multi-decadal hydrological response across the Great Lakes.

78 FR 26319 - Deepwater Horizon Oil Spill; Proposal of Future Early Restoration Projects and Environmental Reviews

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-06

... participate in Trustee decision-making. U.S. Environmental Protection Agency (USEPA); State of Louisiana Coastal Protection and Restoration Authority, Oil Spill Coordinator's Office, Department of Environmental... important species and their nearshore and offshore habitats in the Gulf of Mexico and along the coastal...

Nonlinear Dynamics of the Nearshore Boundary Layer of a Large Lake (Lake Geneva)

NASA Astrophysics Data System (ADS)

Cimatoribus, Andrea A.; Lemmin, U.; Bouffard, D.; Barry, D. A.

2018-02-01

We examine nearshore and pelagic current variability in Lake Geneva, a large and deep lake in western Europe, using observations from several measurement locations and a three-dimensional numerical model for the period 2014-2016. Linear internal seiche modes excited by wind forcing clearly appear as peaks in the energy spectra for measurements in offshore locations. In contrast, spectra from the nearshore data, where currents interact with the lake bed, reveal a negligible contribution of internal seiches to the total kinetic energy. A similar contrast is seen in the spectra obtained from the numerical model at the same locations. Comparing the contribution of the different terms in the vertically averaged momentum equation from the modeling results shows that the nonlinear advective term dominates in the nearshore boundary layer. Its contribution decays with distance from shore. The width of this nearshore boundary layer, which may extend for several kilometers, seems to be mainly determined by local topography. Both field measurements and modeling results indicate that nonlinear dynamics are of primary importance in the nearshore boundary layer.

Spatio-temporal variations in the siphonophore community of the northern South China Sea

NASA Astrophysics Data System (ADS)

Li, Kaizhi; Yin, Jianqiang; Huang, Liangmin; Lian, Shumin; Zhang, Jianlin

2013-03-01

To understand how hydrological and biological factors affect near- to off-shore variations in the siphonophore community, we sampled zooplankton at 82 stations in the northern South China Sea during summer, winter, and spring. Forty-one species of siphonophore were collected by vertical trawling. The species richness of siphonophores increased from the nearshore to offshore regions in all three seasons of investigation, with maximum richness in summer and minimum richness in winter. The abundance of siphonophores was also higher in summer than in spring and winter, concentrated in the nearshore region in the warm season and scattered in the offshore region in the cold season. Four siphonophore groups were classified according to the frequency of occurrence: nearshore, near-offshore, offshore, and tropical pelagic. Among them, the nearshore group had higher abundance nearshore compared with the offshore. The tropical pelagic group had higher species number offshore than nearshore. Spatial and temporal fluctuations in taxonomic composition and abundance of siphonophores were due to the influence of the coastal upwelling and surface ocean currents of the South China Sea, driven by the East Asia monsoonal system.

Development of multi-year land cover data to assess wildfire impacts to coastal watersheds and the nearshore environment

NASA Astrophysics Data System (ADS)

Morrison, Katherine D.

In the Mediterranean ecosystems of coastal California, wildfire is a common disturbance that can significantly alter vegetation in watersheds that transport sediment and nutrients to the adjacent nearshore oceanic environment. We assess the impact of two wildfires that burned in 2008 on land cover and to the nearshore environment along the Big Sur coast in central California. We created a multi-year land cover dataset to assess changes to coastal watersheds as a result of fire. This land cover dataset was then used to model changes in nonpoint source pollutants transported to the nearshore environment. Results indicate post-fire increases in percent export compared to pre-fire years and also link wildfire severity to the specific land cover changes that subsequently increase exports of pollutants and sediment to the nearshore environment. This approach is a replicable across watersheds and also provides a framework for including the nearshore environment as a value at risk terrestrial land management revolving around wildfire, including suppression, thinning, and other activities that change land cover at a landscape scale.

Evaluating Carbonate System Algorithms in a Nearshore System: Does Total Alkalinity Matter?

PubMed Central

Sweet, Julia; Brzezinski, Mark A.; McNair, Heather M.; Passow, Uta

2016-01-01

Ocean acidification is a threat to many marine organisms, especially those that use calcium carbonate to form their shells and skeletons. The ability to accurately measure the carbonate system is the first step in characterizing the drivers behind this threat. Due to logistical realities, regular carbonate system sampling is not possible in many nearshore ocean habitats, particularly in remote, difficult-to-access locations. The ability to autonomously measure the carbonate system in situ relieves many of the logistical challenges; however, it is not always possible to measure the two required carbonate parameters autonomously. Observed relationships between sea surface salinity and total alkalinity can frequently provide a second carbonate parameter thus allowing for the calculation of the entire carbonate system. Here, we assessed the rigor of estimating total alkalinity from salinity at a depth <15 m by routinely sampling water from a pier in southern California for several carbonate system parameters. Carbonate system parameters based on measured values were compared with those based on estimated TA values. Total alkalinity was not predictable from salinity or from a combination of salinity and temperature at this site. However, dissolved inorganic carbon and the calcium carbonate saturation state of these nearshore surface waters could both be estimated within on average 5% of measured values using measured pH and salinity-derived or regionally averaged total alkalinity. Thus we find that the autonomous measurement of pH and salinity can be used to monitor trends in coastal changes in DIC and saturation state and be a useful method for high-frequency, long-term monitoring of ocean acidification. PMID:27893739

Evaluating Carbonate System Algorithms in a Nearshore System: Does Total Alkalinity Matter?

PubMed

Jones, Jonathan M; Sweet, Julia; Brzezinski, Mark A; McNair, Heather M; Passow, Uta

2016-01-01

Ocean acidification is a threat to many marine organisms, especially those that use calcium carbonate to form their shells and skeletons. The ability to accurately measure the carbonate system is the first step in characterizing the drivers behind this threat. Due to logistical realities, regular carbonate system sampling is not possible in many nearshore ocean habitats, particularly in remote, difficult-to-access locations. The ability to autonomously measure the carbonate system in situ relieves many of the logistical challenges; however, it is not always possible to measure the two required carbonate parameters autonomously. Observed relationships between sea surface salinity and total alkalinity can frequently provide a second carbonate parameter thus allowing for the calculation of the entire carbonate system. Here, we assessed the rigor of estimating total alkalinity from salinity at a depth <15 m by routinely sampling water from a pier in southern California for several carbonate system parameters. Carbonate system parameters based on measured values were compared with those based on estimated TA values. Total alkalinity was not predictable from salinity or from a combination of salinity and temperature at this site. However, dissolved inorganic carbon and the calcium carbonate saturation state of these nearshore surface waters could both be estimated within on average 5% of measured values using measured pH and salinity-derived or regionally averaged total alkalinity. Thus we find that the autonomous measurement of pH and salinity can be used to monitor trends in coastal changes in DIC and saturation state and be a useful method for high-frequency, long-term monitoring of ocean acidification.

Larval fish variability in response to oceanographic features in a nearshore nursery area.

PubMed

Pattrick, P; Strydom, N A

2014-09-01

The influence of oceanographic features on ichthyoplankton assemblages in the warm temperate nearshore region of Algoa Bay, South Africa, was assessed. The nearshore ichthyoplankton comprised 88 taxa from 34 families. Samples were collected at six stations between August 2010 and July 2012 using a plankton ring net of 750 mm diameter and 500 µm mesh aperture. The majority of larvae collected were in a preflexion stage, indicating the potential importance of the nearshore for newly hatched larvae. Engraulidae dominated the catch (38·4%), followed by Cynoglossidae (28·1%) and Sparidae (8·4%). Larval fish abundance was highest during austral spring and summer (September to February). Unique patterns in responses of each dominant fish species to oceanographic features in the nearshore indicate the sensitivity of the early developmental stage to environmental variables. Using generalized linear models, ichthyoplankton abundance responded positively to upwelling and when warm water plumes originating from an Agulhas Current meander entered Algoa Bay. Highest abundances of Engraulis encrasicolus and Sardinops sagax were observed during Agulhas Plume intrusions into Algoa Bay. When a mixed and stratified water column persisted in the nearshore region of Algoa Bay, larval fish abundance decreased. The nearshore region of Algoa Bay appears to serve as a favourable environment for the accumulation of ichthyoplankton. © 2014 The Fisheries Society of the British Isles.

Development of a wave-induced forcing threshold for nearshore impact of Wave Energy Converter arrays

NASA Astrophysics Data System (ADS)

O'Dea, A.; Haller, M. C.; Ozkan-Haller, H. T.

2016-02-01

Wave-induced forcing is a function of spatial gradients in the wave radiation stresses and is the main driver of alongshore currents, rip currents, and nearshore sediment transport. The installation of nearshore Wave Energy Converter (WEC) arrays may cause significant changes in the surf zone radiation stresses and could therefore impact nearshore littoral processes. In the first part of this study, a new threshold for nearshore hydrodynamic impact due to the presence of WEC devices is established based on changes in the alongshore radiation stress gradients shoreward of WEC arrays. The threshold is defined based on the relationship between nearshore radiation stresses and alongshore currents as observed in field data. Next, we perform a parametric study of the nearshore impact of WEC arrays using the SWAN wave model. Trials are conducted on an idealized, alongshore-uniform beach with a range of WEC array configurations, locations, and incident wave conditions, and conditions that generate radiation stress gradients above the impact threshold are identified. Finally, the same methodology is applied to two wave energy test sites off the coast of Newport, OR with more complicated bathymetries. Although the trends at the field sites are similar to those seen in the parametric study, the location and extent of the changes in the alongshore radiation stress gradients appear to be heavily influenced by the local bathymetry.

2015 status of the Lake Ontario lower trophic levels

USGS Publications Warehouse

Holeck, Kristen T.; Rudstam, Lars G.; Hotaling, Christopher; McCullough, Russ D.; Lemon, Dave; Pearsall, Web; Lantry, Jana; Connerton, Michael J.; LaPan, Steve; Biesinger, Zy; Lantry, Brian F.; Walsh, Maureen; Weidel, Brian C.

2016-01-01

Offshore spring total phosphorus (TP) in 2015 was 4.2 μ g/L, the same as in 2014; this is lower than 2001 - 2013, but there is no significant time trend 2001 - 2015. Offshore soluble reactive phosphorus (SRP) was very low in 2015; Apr/May - Oct mean values were <1 μ g/L at most sites. SRP has been stable in nearshore and offshore habitats since 1998 (range, 0.4 – 3.3 μ g/L). TP concentrations were low at both nearshore and offshore locations (range 4.2 - 8.1 μ g/L), and TP and SRP concentrations were significantly higher in the nearshore as compared to the offshore (6.8 μ g/L vs 4.8 μ g/L, TP; 1.1 μ g/L vs 0.7 μ g/L, SRP).Chlorophyll-a and Secchi depth values are indicative of oligotrophic conditions in nearshore and offshore habitats. Offshore summer chlorophyll- a declined significantly 2000 - 2015. Nearshore chlorophyll- a increased 1995 - 2004 but then declined 2005 - 2015. Epilimnetic chlorophyll-a averaged between 0.9 and 1.9 1 μg/L across sites, and offshore concentrations (1.4 1 μg/L) were significantly higher than nearshore (1.1 μg/L). Summer Secchi depth increased significantly in the offshore 2000 -2015 and showed no trend in the nearshore, 1995 - 2015. Apr/May - Oct Secchi depth ranged from 5.0 m to 13.0 m at individual sites and was higher in the offshore (9.5 m) than nearshore (6.2 m).In 2015, Apr/May - Oct epilimnetic zooplankton density, size, and biomass were not different between the offshore and the nearshore, but cyclopoid biomass was higher in the offshore (8.3 mg/m 3 vs 2.0 mg/m3) and Bythotrephes biomass was higher in the nearshore (0.17 mg/m3 vs 0.04 mg/m3).Zooplankton density and biomass peaked in September, an atypical pattern. This coincided with peaks in calanoid copepod, daphnid, and Holopedium Holopedium biomass in the nearshore has increased significantly since 1995.The predatory cladoceran Cercopagis continued to be abundant in summer in the nearshore (3.4 μ g/L) but not in the offshore (0.8 μ g/L). Bythotrephes biomass was very low (<0.3 μ g/L) in both nearshore and offshore habitats. Combined biomass of these predatory cladocerans in the offshore was the lowest recorded since 2001.Summer nearshore zooplankton density and biomass declined significantly 1995 - 2004 and then increased significantly 2005 – 2015. The decline was due to reductions in bosminids and cyclopoids and the increase was due mostly to a rebound in bosminids.Summer offshore zooplankton density and biomass increased significantly 2005 - 2015. The increase was due to an increase in bosminids and cyclopoids. In 2015, offshore summer epilimnetic zooplankton biomass was 52 mg/m3 (2005 - 2014 mean=18 mg/m3).Most zooplankton biomass was found in the metalimnion in July and in the hypolimnion in September. Cyclopoids and Limnocalanus dominated the metalimnion and Limnocalanus dominated the hypolimnion. Whole water column samples taken show a stable zooplankton biomass but changing community composition since 2010. Cyclopoids increased 2013 - 2015 and daphnids declined 2014 - 2015.

Cross-shore transport of nearshore sediment by river plume frontal pumping

NASA Astrophysics Data System (ADS)

Horner-Devine, Alexander R.; Pietrzak, Julie D.; Souza, Alejandro J.; McKeon, Margaret A.; Meirelles, Saulo; Henriquez, Martijn; Flores, Raúl P.; Rijnsburger, Sabine

2017-06-01

We present a new mechanism for cross-shore transport of fine sediment from the nearshore to the inner shelf resulting from the onshore propagation of river plume fronts. Onshore frontal propagation is observed in moorings and radar images, which show that fronts penetrate onshore through the nearshore and surf zone, almost to the waterline. During frontal passage a two-layer counterrotating velocity field characteristic of tidal straining is immediately set up, generating a net offshore flow beneath the plume. The seaward flow at depth carries with it high suspended sediment concentrations, which appear to have been generated by wave resuspension in the nearshore region. These observations describe a mechanism by which vertical density stratification can drive exchange of material between the nearshore region and the inner shelf. To our knowledge these are the first observations of this frontal pumping mechanism, which is expected to play an important role in sediment transport near river mouths.

Nearshore thermal gradients of the Colorado River near the Little Colorado River confluence, Grand Canyon National Park, Arizona, 2010

USGS Publications Warehouse

Ross, Rob; Grams, Paul E.

2013-01-01

Construction and operation of Glen Canyon Dam has dramatically impacted the flow of the Colorado River through Glen, Marble, and Grand Canyons. Extremes in both streamflow and water temperature have been suppressed by controlled releases from the dam. Trapping of sediment in Lake Powell, the reservoir formed by Glen Canyon Dam, has also dramatically reduced the supply of suspended sediment entering the system. These changes have altered the riverine ecosystem and the habitat of native species, including fish such as the endangered humpback chub (Gila cypha). Most native fish are adapted to seasonally warm water, and the continuous relatively cold water released by the dam is one of the factors that is believed to limit humpback chub growth and survival. While average mainstem temperatures in the Colorado River are well documented, there is limited understanding of temperatures in the nearshore environments that fish typically occupy. Four nearshore geomorphic unit types were studied between the confluence of the Colorado and Little Colorado Rivers and Lava Canyon in the summer and fall of 2010, for study periods of 10 to 27 days. Five to seven sites were studied during each interval. Persistent thermal gradients greater than the 0.2 °C accuracy of the instruments were not observed in any of the sampled shoreline environments. Temperature gradients between the shoreline and mainstem on the order of 4 °C, believed to be important to the habitat-seeking behavior of native or nonnative fishes, were not detected.

Long Wavelength Ripples in the Nearshore

NASA Astrophysics Data System (ADS)

Alcinov, T.; Hay, A. E.

2008-12-01

Sediment bedforms are ubiquitous in the nearshore environment, and their characteristics and evolution have a direct effect on the hydrodynamics and the rate of sediment transport. The focus of this study is long wavelength ripples (LWR) observed at two locations in the nearshore at roughly 3m water depth under combined current and wave conditions in Duck, North Carolina. LWR are straight-crested bedforms with wavelengths in the range of 20-200cm, and steepness of about 0.1. They occur in the build up and decay of storms, in a broader range of values of the flow parameters compared to other ripple types. The main goal of the study is to test the maximum gross bedform-normal transport (mGBNT) hypothesis, which states that the orientation of ripples in directionally varying flows is such that the gross sediment transport normal to the ripple crest is maximized. Ripple wavelengths and orientation are measured from rotary fanbeam images and current and wave conditions are obtained from electromagnetic (EM) flowmeters and an offshore pressure gauge array. Preliminary tests in which transport direction is estimated from the combined flow velocity vectors indicate that the mGBNT is not a good predictor of LWR orientation. Results from tests of the mGBNT hypothesis using a sediment transport model will be presented.

Influence of Wave Energetics on Nearshore Storms and Adjacent Shoreline Morphology

NASA Astrophysics Data System (ADS)

Wadman, H. M.; McNinch, J. E.; Hanson, J.

2008-12-01

Large-scale climatic forcings (such as NAO and ENSO) are known to induce fluctuations in regional storm frequency and intensity. Morphology-based studies have traditionally focused on individual storms and their influence on the nearshore coastal wave regime and shoreline response. Few studies have attempted to link long-term observed changes in shoreline position, beach, and nearshore morphology with large-scale climatic forcings that influence regional storm patterns. In order to predict the response of coastlines to future sea level rise and climate change, we need to understand how changes in the frequency of storms affecting nearshore regions (nearshore storms) may influence trends in shoreline position and nearshore morphology. Nearly 30 years of wave data (deep and shallow) collected off of Duck, NC are examined for trends in storm frequency and/or intensity. Changes in shoreline position and shoreface elevation, as observed from monthly beach transects over the same period, are also investigated in light of the observed trends in hydrodynamic forcings. Our preliminary analysis was unable to identify any consistent linear trends (increases or decreases) in frequency or intensity over the ~30-year time period in either the offshore wave heights or the nearshore storm record. These data might suggest that previous observations of recent increases in storm intensity and frequency, speculated to be due to climate change, might be spatially limited. Future analyses will partition the contributions from individual wind sea and swell events in order to better identify long-term trends in wave energetics from the various wave generation regions in the Atlantic. At this location, offshore wave height and the nearshore storm record are dominated by seasonal fluctuations and a strong interdecadal- to decadal periodicity. Previous research in Duck, NC has suggested that changes in shoreline position and shoreface elevations are related both to seasonal trends as well as "storm groupiness". Our analyses support these findings, but also identify interdecadal- to decadal trends in the nearshore morphology. Despite these fluctuations, the overall position of the shoreline and elevation of the shoreface shows little net change over the 30 years investigated. We hypothesize that the interdecadal- to decadal periodicity in the morphology is driven largely by the influences of large-scale climatic forcings on the nearshore wave regime as reflected in the storm record. We also explore the relationship between morphological periodicity, storm and wave height periodicity, and climatic fluctuations.

The future of nearshore processes research

USGS Publications Warehouse

Elko, Nicole A.; Feddersen, Falk; Foster, Diane; Hapke, Cheryl J.; McNinch, Jesse E.; Mulligan, Ryan P.; Tuba Ӧzkan-Haller, H.; Plant, Nathaniel G.; Raubenheimer, Britt

2014-01-01

The nearshore is the transition region between land and the continental shelf including (from onshore to offshore) coastal plains, wetlands, estuaries, coastal cliffs, dunes, beaches, surf zones (regions of wave breaking), and the inner shelf (Figure ES-1). Nearshore regions are vital to the national economy, security, commerce, and recreation. The nearshore is dynamically evolving, is often densely populated, and is under increasing threat from sea level rise, long-term erosion, extreme storms, and anthropogenic influences. Worldwide, almost one billion people live at elevations within 10 m of present sea level. Long-term erosion threatens communities, infrastructure, ecosystems, and habitat. Extreme storms can cause billions of dollars of damage. Degraded water quality impacts ecosystem and human health. Nearshore processes, the complex interactions between water, sediment, biota, and humans, must be understood and predicted to manage this often highly developed yet vulnerable nearshore environment. Over the past three decades, the understanding of nearshore processes has improved. However, societal needs are growing with increased coastal urbanization and threats of future climate change, and significant scientific challenges remain. To address these challenges, members of academia, industry, and federal agencies (USGS, USACE, NPS, NOAA, FEMA, ONR) met at the “The Past and Future of Nearshore Processes Research: Reflections on the Sallenger Years and a New Vision for the Future” workshop to develop a nearshore processes research vision where societal needs and science challenges intersect. The resulting vision is comprised of three broad research themes: Long-term coastal evolution due to natural and anthropogenic processes: As global climate change alters the rates of sea level rise and potentially storm patterns and coastal urbanization increases over the coming decades, an understanding of coastal evolution is critical. Improved knowledge of long-term morphological, ecological, and societal processes and their interactions will result in an improved ability to simulate coastal change. This will enable proactive solutions for resilient coasts and better guidance for reducing coastal vulnerability.Extreme Events: Flooding, erosion, and the subsequent recovery: Hurricane Sandy caused flooding and erosion along hundreds of miles of shoreline, flooded New York City, and impacted communities and infrastructure. Overall U.S. coastal extreme event related economic losses have increased substantially. Furthermore, climate change may cause an increase in coastal extreme events and rising sea levels could increase the occurrence of extreme events. Addressing this research theme will result in an improved understanding of the physical processes during extreme events, leading to improved models of flooding, erosion, and recovery. The resulting societal benefit will be more resilient coastal communities.The physical, biological and chemical processes impacting human and ecosystem health: Nearshore regions are used for recreation, tourism, and human habitation, and provide habitat and valuable ecosystem services. These areas must be sustained for future generations, however overall coastal water quality is declining due to microbial pathogens, fertilizers, pesticides, and heavy metal contamination, threatening ecosystem and human health. To ensure sustainable nearshore regions, predictive real-time water- and sediment-based based pollutant modeling capabilities must be developed, which requires expanding our knowledge of the physics, chemistry, and biology of the nearshore. The resulting societal benefits will include better beach safety, healthier ecosystems, and improved mitigation and regulatory policies.The scientists and engineers of the U.S. nearshore community are poised to make significant progress on these research themes, which have significant societal impact. The U.S. nearshore community, including academic, government, and industry colleagues, recommends multi-agency investment into a coordinated development of observational and modeling research infrastructure to address these themes, as discussed in the whitepaper. The observational infrastructure should include development of new sensors and methods, focused observational programs, and expanded nearshore observing systems. The modeling infrastructure should include improved process representation, better model coupling, incorporation of data assimilation techniques, and testing of real-time models. The observations will provide test beds to compare and improve models.

Nearshore Placement Techniques in Southern Lake Michigan

DTIC Science & Technology

2018-03-01

ER D C /C HL T R- 18 -3 Regional Sediment Management (RSM) Program Nearshore Placement Techniques in Southern Lake Michigan Co as ta...online library at http://acwc.sdp.sirsi.net/client/default. Regional Sediment Management (RSM) Program ERDC/CHL TR-18-3 March 2018 Nearshore...This study was conducted for Headquarters, U.S. Army Corps of Engineers (HQUSACE), Washington, DC, under the USACE Regional Sediment Management

Impact of Varying Wave Conditions on the Mobility of Arsenic in a Nearshore Aquifer on the Great Lakes

NASA Astrophysics Data System (ADS)

Rakhimbekova, S.; O'Carroll, D. M.; Robinson, C. E.

2017-12-01

Groundwater-coastal water interactions play an important role in controlling the behavior of inorganic chemicals in nearshore aquifers and the subsequent flux of these chemicals to receiving coastal waters. Previous studies have shown that dynamic groundwater flows and water exchange across the sediment-water interface can set up strong geochemical gradients and an important reaction zone in a nearshore aquifer that affect the fate of reactive chemicals. There is limited understanding of the impact of transient coastal forcing such as wave conditions on groundwater dynamics and geochemistry in a nearshore aquifer. The goal of this study was to assess the impact of intensified wave conditions on the behavior of arsenic in a nearshore aquifer and to determine the hydrological and geochemical factors controlling its fate and ultimate delivery to receiving coastal waters. Field investigations were conducted over the period of intensified wave conditions on a freshwater beach on Lake Erie, Canada. High spatial resolution aqueous and sediment sampling was conducted to characterize the subsurface distribution of inorganic species in the nearshore aquifer. Numerical groundwater flow and transport simulations were conducted to evaluate wave-induced perturbations in the flow dynamics including characterizing changes in the groundwater flow recirculations in the nearshore aquifer. The combination of field data and numerical simulations reveal that varying wave conditions alter groundwater flows and set up geochemical transition zones within the aquifer resulting in the release and sequestration of arsenic. Interactions between oxic surface water, mildly reducing shallow groundwater, and reducing sulfur- and iron-rich deep groundwater promote dynamic iron, sulfur and manganese cycling which control the mobility of arsenic in the aquifer. The findings of this study have potential implications for the fate and transport of other reactive chemicals (e.g. phosphorus, mercury) in nearshore marine and freshwater aquifers exposed to transient coastal forcing. Understanding the fate of chemicals and the dynamics of the reaction zone in nearshore aquifers is critical for evaluating the importance of groundwater as a pathway for delivering pollutants to coastal waters.

Storm Observations of Persistent Three-Dimensional Shoreline Morphology and Bathymetry Along a Geologically Influenced Shoreface Using X-Band Radar (BASIR)

NASA Astrophysics Data System (ADS)

Brodie, K. L.; McNinch, J. E.

2008-12-01

Accurate predictions of shoreline response to storms are contingent upon coastal-morphodynamic models effectively synthesizing the complex evolving relationships between beach topography, sandbar morphology, nearshore bathymetry, underlying geology, and the nearshore wave-field during storm events. Analysis of "pre" and "post" storm data sets have led to a common theory for event response of the nearshore system: pre-storm three-dimensional bar and shoreline configurations shift to two-dimensional, linear forms post- storm. A lack of data during storms has unfortunately left a gap in our knowledge of how the system explicitly changes during the storm event. This work presents daily observations of the beach and nearshore during high-energy storm events over a spatially extensive field site (order of magnitude: 10 km) using Bar and Swash Imaging Radar (BASIR), a mobile x-band radar system. The field site contains a complexity of features including shore-oblique bars and troughs, heterogeneous sediment, and an erosional hotspot. BASIR data provide observations of the evolution of shoreline and bar morphology, as well as nearshore bathymetry, throughout the storm events. Nearshore bathymetry is calculated using a bathymetry inversion from radar- derived wave celerity measurements. Preliminary results show a relatively stable but non-linear shore-parallel bar and a non-linear shoreline with megacusp and embayment features (order of magnitude: 1 km) that are enhanced during the wave events. Both the shoreline and shore-parallel bar undulate at a similar spatial frequency to the nearshore shore- oblique bar-field. Large-scale shore-oblique bars and troughs remain relatively static in position and morphology throughout the storm events. The persistence of a three-dimensional shoreline, shore-parallel bar, and large-scale shore-oblique bars and troughs, contradicts the idea of event-driven shifts to two- dimensional morphology and suggests that beach and nearshore response to storms may be location specific. We hypothesize that the influence of underlying geology, defined by (1) the introduction of heterogeneous sediment and (2) the possible creation of shore-oblique bars and troughs in the nearshore, may be responsible for the persistence of three-dimensional forms and the associated shoreline hotspots during storm events.

Conservation status and spatial patterns of AGRRA vitality indices in Southwestern Atlantic reefs.

PubMed

Kikuchi, Ruy K P; Leão, Zelinda M A N; Oliveira, Marília D M

2010-05-01

Coral reefs along the Eastern Brazilian coast extend for a distance of 800 km from 12 degrees to 18 degrees S. They are the largest and the richest reefs of Brazil coasts, and represent the Southernmost coral reefs of the Southwestern Atlantic Ocean. Few reef surveys were performed in the 90's in reef areas of Bahia State, particularly in the Abrolhos reef complex, in the Southernmost side of the state. A monitoring program applying the Atlantic and Gulf Rapid Reef Assessment (AGRRA) protocol was initiated in 2000, in the Abrolhos National Marine Park, after the creation of the South Tropical America (STA) Regional Node of the Global Coral Reef Monitoring Network (GCRMN) by the end of 1999. From that time up to 2005, nine reef surveys were conducted along the coast of the State of Bahia, including 26 reefs, with 95 benthic sites, 280 benthic transects, 2025 quadrats and 3537 stony corals. Eighteen of the 26 investigated reefs were assessed once and eight reefs of Abrolhos were surveyed twice to four times. The MDS ordination, analysis of similarity (ANOSIM, one way and two-way nested layouts) and similarity percentages (SIMPER) tests were applied to investigate the spatial and temporal patterns of reef vitality. Four indicators of the coral vitality: live coral cover, the density of the larger corals (colonics > 20cm per reef site) and of the coral recruits (colonies < 2cm per square meter), and the percentage of macroalgae indicate that the nearshore reefs, which are located less than 5 km from the coast, are in poorer condition than the reefs located more than 5 km off the coast. A higher density of coral colonies, lower macroalgal index, higher relative percent of turf algae and higher density of coral recruits in offshore reefs compared to the nearshore reefs are the conditions that contribute more than 80% to the dissimilarity between them. The offshore reefs are in better vital condition than the nearshore reefs and have a set of vitality indices more closely related to the Northwestern Atlantic reefs than the nearshore reef. These have been most severely impacted by the effects of direct human activities such as cuthrophic waters associated with sewage pollution, higher sedimentation rates and water turbidity, inadequate use of the reefs and over exploitation of their resources. The implementation of a more effective coral reef monitoring program in Bahia is mandatory, in order to improve the strategies for protection and management efforts of the reefs.

California coast nearshore processes study

NASA Technical Reports Server (NTRS)

Pirie, D. M. (Principal Investigator); Steller, D. D.

1973-01-01

The author has identified the following significant results. Remote sensor aircraft flights took place simultaneously with ERTS-1 overpasses at the San Francisco, Monterey Bay, and Santa Barbara test cells. The cameras and scanners used were configured for detecting suspended sediment and for maximum water penetration. The Ektachrome/Wratten 12 photographs which were intentionally overexposed 1-1/2 stops were found to show the most extensive sediment transport detail. Minus blue/K 2 photographs illustrate nearshore underwater bottom detail including the head of the Mugu submarine canyon. The EMSIDE 9 channel scanner was employed to classify and differentiate suspended sediment, oil, kelp, and other materials found in the nearshore area. Processing of bulk ERTS-1 computer compatible tapes was utilized to enhance and analyze nearshore sediments. This technique was most successful in enhancing subtle nearshore features found to be faint or invisible on prints made from the supplied negatives. In addition to this continuing computer process, an effort was initiated to interface density values from the bulk tapes into contouring and mapping software.

Severe impacts of brown tides caused by Sargassum spp. on near-shore Caribbean seagrass communities.

PubMed

van Tussenbroek, Brigitta I; Hernández Arana, Héctor A; Rodríguez-Martínez, Rosa E; Espinoza-Avalos, Julio; Canizales-Flores, Hazel M; González-Godoy, Carlos E; Barba-Santos, M Guadalupe; Vega-Zepeda, Alejandro; Collado-Vides, Ligia

2017-09-15

From mid-2014 until the end of 2015, the Mexican Caribbean coast experienced a massive influx of drifting Sargassum spp. that accumulated on the shores, resulting in build-up of decaying beach-cast material and near-shore murky brown waters (Sargassum-brown-tides, Sbt). The effects of Sbt on four near-shore waters included reduction in light, oxygen (hypoxia or anoxia) and pH. The monthly influx of nitrogen, and phosphorus by drifting Sargassum spp. was estimated at 6150 and 61kgkm -1 respectively, resulting in eutrophication. Near-shore seagrass meadows dominated by Thalassia testudinum were replaced by a community dominated by calcareous rhizophytic algae and drifting algae and/or epiphytes, resulting in 61.6-99.5% loss of below-ground biomass. Near-shore corals suffered total or partial mortality. Recovery of affected seagrass meadows may take years or even decades, or changes could be permanent if massive influxes of Sargassum spp. recur. Copyright © 2017. Published by Elsevier Ltd.

Detection of pharmaceuticals and personal care products (PPCPs) in near-shore habitats of southern Lake Michigan.

PubMed

Ferguson, Patrick J; Bernot, Melody J; Doll, Jason C; Lauer, Thomas E

2013-08-01

Pharmaceuticals and personal care products (PPCPs) have been documented throughout the United States freshwaters but research has focused largely on lotic systems. Because PPCPs are designed to have a physiological effect, it is likely that they may also influence aquatic organisms. Thus, PPCPs may negatively impact aquatic ecosystems. The objectives of this research were to quantify PPCP abundance in near-shore habitats of southern Lake Michigan and identify factors related to PPCP abundance. Stratified sampling was conducted seasonally at four southern Lake Michigan sites. All sites and depths had measurable PPCP concentrations, with mean individual compound concentrations of acetaminophen (5.36 ng/L), caffeine (31.0 ng/L), carbamazepine (2.23 ng/L), cotinine (4.03 ng/L), gemfibrozil (7.03 ng/L), ibuprofen (7.88 ng/L), lincomycin (4.28 ng/L), naproxen (6.32 ng/L), paraxanthine (1,7-dimethylxanthine; 46.2 ng/L), sulfadimethoxine (0.94 ng/L), sulfamerazine (0.92 ng/L), sulfamethazine (0.92 ng/L), sulfamethoxazole (26.0 ng/L), sulfathiazole (0.92 ng/L), triclocarban (5.72 ng/L), trimethoprim (5.15 ng/L), and tylosin (3.75 ng/L). Concentrations of PPCPs varied significantly among sampling times and locations (river mouth vs offshore), with statistical interactions between the main effects of site and time as well as time and location. Concentrations of PPCPs did not differ with site or depth. Temperature, total carbon, total dissolved solids, dissolved oxygen, and ammonium concentrations were related to total pharmaceutical concentrations. These data indicate that PPCPs are ubiquitous and persistent in southern Lake Michigan, potentially posing harmful effects to aquatic organisms. Copyright © 2013 Elsevier B.V. All rights reserved.

Satellite Observations of Coastal Processes from a Geostationary Orbit: Application to estuarine, coastal, and ocean resource management

NASA Astrophysics Data System (ADS)

Tzortziou, M.; Mannino, A.; Schaeffer, B. A.

2016-02-01

Coastal areas are among the most vulnerable yet economically valuable ecosystems on Earth. Estuaries and coastal oceans are critically important as essential habitat for marine life, as highly productive ecosystems and a rich source of food for human consumption, as a strong economic driver for coastal communities, and as a highly dynamic interface between land and ocean carbon and nutrient cycles. Still, our present capabilities to remotely observe coastal ocean processes from space are limited in their temporal, spatial, and spectral resolution. These limitations, in turn, constrain our ability to observe and understand biogeochemical processes in highly dynamic coastal ecosystems, or predict their response and resilience to current and future pressures including sea level rise, coastal urbanization, and anthropogenic pollution.On a geostationary orbit, and with high spatial resolution and hyper-spectral capabilities, NASA's Decadal Survey mission GEO-CAPE (GEO-stationary for Coastal and Air Pollution Events) will provide, for the first time, a satellite view of the short-term changes and evolution of processes along the economically invaluable but, simultaneously, particularly vulnerable near-shore waters of the United States. GEO-CAPE will observe U.S. lakes, estuaries, and coastal regions at sufficient temporal and spatial scales to resolve near-shore processes, tides, coastal fronts, and eddies, track sediments and pollutants, capture diurnal biogeochemical processes and rates of transformation, monitor harmful algal blooms and large oil spills, observe episodic events and coastal hazards. Here we discuss the GEO-CAPE applications program and the new capabilities afforded by this future satellite mission, to identify potential user communities, incorporate end-user needs into future mission planning, and allow integration of science and management at the coastal interface.

Satellite Observations of Coastal Processes from a Geostationary Orbit: Application to estuarine, coastal, and ocean resource management

NASA Astrophysics Data System (ADS)

Tzortziou, M.; Mannino, A.; Schaeffer, B. A.

2016-12-01

Coastal areas are among the most vulnerable yet economically valuable ecosystems on Earth. Estuaries and coastal oceans are critically important as essential habitat for marine life, as highly productive ecosystems and a rich source of food for human consumption, as a strong economic driver for coastal communities, and as a highly dynamic interface between land and ocean carbon and nutrient cycles. Still, our present capabilities to remotely observe coastal ocean processes from space are limited in their temporal, spatial, and spectral resolution. These limitations, in turn, constrain our ability to observe and understand biogeochemical processes in highly dynamic coastal ecosystems, or predict their response and resilience to current and future pressures including sea level rise, coastal urbanization, and anthropogenic pollution.On a geostationary orbit, and with high spatial resolution and hyper-spectral capabilities, NASA's Decadal Survey mission GEO-CAPE (GEO-stationary for Coastal and Air Pollution Events) will provide, for the first time, a satellite view of the short-term changes and evolution of processes along the economically invaluable but, simultaneously, particularly vulnerable near-shore waters of the United States. GEO-CAPE will observe U.S. lakes, estuaries, and coastal regions at sufficient temporal and spatial scales to resolve near-shore processes, tides, coastal fronts, and eddies, track sediments and pollutants, capture diurnal biogeochemical processes and rates of transformation, monitor harmful algal blooms and large oil spills, observe episodic events and coastal hazards. Here we discuss the GEO-CAPE applications program and the new capabilities afforded by this future satellite mission, to identify potential user communities, incorporate end-user needs into future mission planning, and allow integration of science and management at the coastal interface.

Mapping bathymetry in an active surf zone with the WorldView2 multispectral satellite

NASA Astrophysics Data System (ADS)

Trimble, S. M.; Houser, C.; Brander, R.; Chirico, P.

2015-12-01

Rip currents are strong, narrow seaward flows of water that originate in the surf zones of many global beaches. They are related to hundreds of international drownings each year, but exact numbers are difficult to calculate due to logistical difficulties in obtaining accurate incident reports. Annual average rip current fatalities are estimated to be ~100, 53 and 21 in the United States (US), Costa Rica, and Australia respectively. Current warning systems (e.g. National Weather Service) do not account for fine resolution nearshore bathymetry because it is difficult to capture. The method shown here could provide frequent, high resolution maps of nearshore bathymetry at a scale required for improved rip prediction and warning. This study demonstrates a method for mapping bathymetry in the surf zone (20m deep and less), specifically within rip channels, because rips form at topographically low spots in the bathymetry as a result of feedback amongst waves, substrate, and antecedent bathymetry. The methods employ the Digital Globe WorldView2 (WV2) multispectral satellite and field measurements of depth to generate maps of the changing bathymetry at two embayed, rip-prone beaches: Playa Cocles, Puerto Viejo de Talamanca, Costa Rica, and Bondi Beach, Sydney, Australia. WV2 has a 1.1 day pass-over rate with 1.84m ground pixel resolution of 8 bands, including 'yellow' (585-625 nm) and 'coastal blue' (400-450 nm). The data is used to classify bottom type and to map depth to the return in multiple bands. The methodology is tested at each site for algorithm consistency between dates, and again for applicability between sites.

Archive of bathymetry and backscatter data collected in 2014 nearshore Breton and Gosier Islands, Breton National Wildlife Refuge, Louisiana

USGS Publications Warehouse

DeWitt, Nancy T.; Fredericks, Jake J.; Flocks, James G.; Miselis, Jennifer L.; Locker, Stanley D.; Kindinger, Jack G.; Bernier, Julie C.; Kelso, Kyle W.; Reynolds, Billy J.; Wiese, Dana S.; Browning, Trevor

2016-08-01

As part of the Barrier Island Monitoring Project, scientists from the U.S. Geological Survey (USGS) St. Petersburg Coastal and Marine Science Center conducted nearshore geophysical surveys off Breton and Gosier Islands, Louisiana, in July and August of 2014. To assist the United States Fish and Wildlife Service (USFWS) with restoration planning efforts, the USGS was tasked with answering fundamental questions about the physical environment of the southern Chandeleur Islands, including the geology, morphology, and oceanography. Baseline data needed to answer these questions were either insufficient or missing. The USGS conducted a comprehensive geologic investigation in the summer of 2014, collecting geophysical and sedimentological data.Breton Island, located at the southern end of the Chandeleur Island chain in southeastern Louisiana, was recognized as a natural, globally significant nesting sanctuary for several bird species and was established as the Breton National Wildlife Refuge (NWR) in 1904. The areal extent of Breton Island has diminished 90 percent since 1920. Land loss is attributed to ongoing relative sea-level rise, diminished sediment supply, and storm impacts. The bird population on Breton Island has also declined over the years, most notably after Hurricane George in 1998 and after Hurricane Katrina in 2015; the latter completely submerged the island. Despite decreasing habitable acreage, migratory seabirds continue to return and nest on Breton Island. To prevent the island from being submerged in the future, and to protect, stabilize, and provide more nesting and foraging areas for the bird population, the USFWS proposed a restoration effort to rebuild Breton Island to its pre-Katrina footprint.This data series serves as an archive of processed interferometric swath and single-beam bathymetry data, and side-scan sonar data, collected in the nearshore of Breton and Gosier Islands, NWR, Louisiana. The data were collected during two USGS cruises (USGS Field Activity Numbers 2014-314-FA and 2014-317-FA) in July and August 2014. Geographic information system data products include a 100-meter-cell-size interpolated bathymetry grid, trackline maps, and point data files. Additional files include error analysis maps, Field Activity Collection System logs, and formal Federal Geographic Data Committee metadata.NOTE: These data are scientific in nature and are not to be used for navigation. Any use of trade names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

A Variational Assimilation System for Nearshore Wave Modeling

DTIC Science & Technology

2013-05-01

shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number ...5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 6. AUTHOR(S) 7...PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10

Nearshore energy subsidies support Lake Michigan fishes and invertebrates following major changes in food web structure

USGS Publications Warehouse

Turschak, Benjamin A; Bunnell, David B.; Czesny, Sergiusz J.; Höök, Tomas O.; Janssen, John; Warner, David M.; Bootsma, Harvey A

2014-01-01

Aquatic food webs that incorporate multiple energy channels (e.g. nearshore benthic or pelagic) with varying productivity and turnover rates convey stability to biological communities by providing multiple independent energy sources. Within the Lake Michigan food web, invasive dreissenid mussels have caused rapid changes to food web structure and potentially altered the channels through which consumers acquire energy. We used stable C and N isotopes to determine how Lake Michigan food web structure has changed in the past decade, coincident with the expansion of dreissenid mussels, decreased pelagic phytoplankton production and increased nearshore benthic algal production. Fish and invertebrate samples collected from sites around Lake Michigan were analyzed to determine taxa-specific 13C:12C (delta 13C) and 15N:14N (delta 15N) ratios. Sampling took place during two distinct periods, 2002-2003 and 2010-2012, that spanned the period of dreissenid expansion, and included nearshore, pelagic and profundal fish and invertebrate taxa. Magnitude and direction of the 13C shift indicated significantly greater reliance upon nearshore benthic energy sources among nearly all fish taxa as well as profundal invertebrates. Although the mechanisms underlying this 13C shift likely varied among species, possible causes include the transport of benthic algal production to offshore waters and an increased reliance on nearshore prey items. Delta 15N shifts were more variable and of smaller magnitude across taxa although declines in delta 15N among some pelagic fishes may indicate a shift to alternative prey resources. Lake Michigan fishes and invertebrates appear to have responded to dreissenid induced changes in nutrient and energy pathways by switching from pelagic to alternative nearshore energy subsidies. Although large shifts in energy allocation (i.e. pelagic to nearshore benthic) resulting from invasive species appear to have affected total production at upper trophic levels, changes in trophic structure and utilization of novel energy pathways may help to stabilize food webs following species invasions.

The Future of Nearshore Processes Research: U.S. Integrated Coastal Research Program

NASA Astrophysics Data System (ADS)

Elko, N.; Feddersen, F.; Foster, D. L.; Hapke, C. J.; Holman, R. A.; McNinch, J.; Mulligan, R. P.; Ozkan-Haller, H. T.; Plant, N. G.; Raubenheimer, B.

2016-02-01

The authors, representing the acting Nearshore Advisory Council, have developed an implementation plan for a U.S. Nearshore Research Program based on the 2015 Future of Nearshore Processes report that was authored by the nearshore community. The objectives of the plan are to link research programs across federal agencies, NGOs, industry, and academia into an integrated national program and to increase academic and NGO participation in federal agency nearshore processes research. A primary recommendation is interagency collaboration to build a research program that will coordinate and fund U.S. nearshore processes research across three broad research themes: 1) long-term coastal evolution due to natural and anthropogenic processes; 2) extreme events; and 3) physical, biological and chemical processes impacting human and ecosystem health. The plan calls for a new program to be developed by an executive committee of federal agency leaders, NGOs, and an academic representative, created similarly to the existing NOPP program. This leadership will be established prior to the 2016 Ocean Sciences meeting and will have agreed on responsibilities and a schedule for development of the research program. To begin to understand the scope of today's U.S. coastal research investment, a survey was distributed to ten federal agency R&D program heads. Six of the ten agencies indicated that they fund coastal research, with a combined annual coastal research budget of nearly 100 million (NSF has not responded). The priority of the three research themes were ranked nearly equally and potential research support ranged from 15-19 million for each theme, with approximately 12 million as direct contribution to academic research. Beyond addressing our fundamental science questions, it is critical that the nearshore community stay organized to represent academic interests on the new executive committee. The program goal is the integration of academic, NGO, and federal agencies.

Remote sensing and the pelagic fisheries environment off Oregon

NASA Technical Reports Server (NTRS)

Pearcy, W. G.

1970-01-01

Remote sensing oceanography at Oregon State University is part of a multidisciplinary research program: (1) to learn more about nearshore oceanographic processes and how they affect the production of marine life and the availability of albacore tuna; and (2) to provide fishermen with information in near real time that will be useful in scouting for albacore concentrations.

2014 status of the Lake Ontario lower trophic levels

USGS Publications Warehouse

Holeck, Kristen T.; Rudstam, Lars G.; Hotaling, Christopher; McCullough, Russ D.; Lemon, Dave; Pearsall, Web; Lantry, Jana; Connerton, Michael J.; LaPan, Steve; Biesinger, Zy; Lantry, Brian F.; Walsh, Maureen; Weidel, Brian C.

2015-01-01

Soluble reactive phosphorus (SRP) concentrations have been stable in nearshore and offshore habitats since 1998 (0.4 – 3.3 μg/L). SRP concentrations were low in 2014; Apr/May – Oct mean values were <1 μg/L at most sites. Spring TP concentrations at individual sites exceeded 10 μg/L on occasion, but spring means were below the 10 μg/L target set by the Great Lakes Water Quality Agreement of 1978 for offshore waters of Lake Ontario. TP concentrations were low at both nearshore and offshore locations; Apr/May – Oct mean values from individual sites ranged from 4.6 – 9.1 μg/L. Spring TP has declined significantly in the longer data series (since 1981), but not since 1995 indicating stable nutrient loading into Lake Ontario for nearly two decades. It averaged 7.8 μg/L in the nearshore and 5.6 μg/L in the offshore in 2014.Chlorophyll-a and secchi depth values are indicative of oligotrophic conditions in nearshore and offshore habitats. Offshore summer chlorophyll-a declined significantly in both the short- (2000-2014) and long-term (1981-2014) time series at a rate of 4-6% per year. Nearshore chlorophyll-a increased after 2003 but then declined again after 2009. Epilimnetic chlorophyll-a averaged between 0.6 and 1.6 μg/L across sites with no difference between nearshore and offshore habitats. Apr/May – Oct Secchi depth ranged from 4.0 m to 10.8 m at individual sites and was higher in the offshore (average 9.1 m) than nearshore (5.9 m).In 2014, Apr/May – Oct epilimnetic zooplankton density, size, and biomass were not different between the offshore and the nearshore, and there were no differences in epilimnetic biomass between offshore and nearshore areas for any of the zooplankton groups.Zooplankton density and biomass peaked in September, an atypical pattern. This coincided with peaks in calanoid copepod, daphnid, and Holopedium biomass. Holopedium biomass in the nearshore increased significantly since 1995.The predatory cladoceran Cercopagis continued to be abundant in the summer, peaking at ~10 mg/m3in the offshore. Bythotrephes biomass was at its lowest level since 2005 in both offshore and nearshore habitats.Summer nearshore zooplankton density and biomass have declined significantly since 1995 at rates of 9-10% per year but have remained stable since 2005. However, bosminids and daphnids increased in 2013 and 2014.Summer offshore zooplankton density and biomass declined significantly in the long-term (since 1981), but remained at a lower stable level 2000 – 2014. A positive change point in 2013 is due to increases in bosminids, cyclopoid copepods, and daphnids.The observed decline in zooplankton biomass may be due in part to redistribution of zooplankton throughout the water column. Most of the zooplankton biomass was in the metalimnion and hypolimnion during the stratified period in 2014. By October, the bulk of the biomass was in the epilimnion.

Thatcher Bay, Washington, Nearshore Restoration Assessment

USGS Publications Warehouse

Breems, Joel; Wyllie-Echeverria, Sandy; Grossman, Eric E.; Elliott, Joel

2009-01-01

The San Juan Archipelago, located at the confluence of the Puget Sound, the Straits of Juan de Fuca in Washington State, and the Straits of Georgia, British Columbia, Canada, provides essential nearshore habitat for diverse salmonid, forage fish, and bird populations. With 408 miles of coastline, the San Juan Islands provide a significant portion of the available nearshore habitat for the greater Puget Sound and are an essential part of the regional efforts to restore Puget Sound (Puget Sound Shared Strategy 2005). The nearshore areas of the San Juan Islands provide a critical link between the terrestrial and marine environments. For this reason the focus on restoration and conservation of nearshore habitat in the San Juan Islands is of paramount importance. Wood-waste was a common by-product of historical lumber-milling operations. To date, relatively little attention has been given to the impact of historical lumber-milling operations in the San Juan Archipelago. Thatcher Bay, on Blakely Island, located near the east edge of the archipelago, is presented here as a case study on the restoration potential for a wood-waste contaminated nearshore area. Case study components include (1) a brief discussion of the history of milling operations. (2) an estimate of the location and amount of the current distribution of wood-waste at the site, (3) a preliminary examination of the impacts of wood-waste on benthic flora and fauna at the site, and (4) the presentation of several restoration alternatives for the site. The history of milling activity in Thatcher Bay began in 1879 with the construction of a mill in the southeastern part of the bay. Milling activity continued for more than 60 years, until the mill closed in 1942. Currently, the primary evidence of the historical milling operations is the presence of approximately 5,000 yd3 of wood-waste contaminated sediments. The distribution and thickness of residual wood-waste at the site was determined by using sediment coring and GIS-based interpolation techniques. Additionally, pilot studies were conducted to characterize in place sediment redox, organic composition, and sulfide impacts to nearshore flora and fauna. We found that the presence of wood-waste in Thatcher Bay may alter the quality of the benthic habitat by contributing to elevated levels of total organic composition (TOC) of the sediment. Increased TOC favors anaerobic respiration in marine sediments, and sulfide, a toxic by-product of this process, was found at levels as high as 17.5 mg L-1 in Thatcher Bay. The Thatcher Bay sulfide levels are several orders of magnitude higher than those known to impact benthic invertebrates. Eelgrass, Zostera marina, located on the western margin of Thatcher Bay, was surveyed by using underwater video surveys. This baseline distribution will in part be used to measure the impact of any future remediation efforts. Additionally, the distribution and survey data can provide an estimate of propagule source for future colonization of restored sediment. Three restoration alternatives were considered, and a ranking matrix was developed to score each alternative against site-specific and regional criteria. The process identified the removal of wood-waste from a water-based platform as the preferred alternative. Our multidisciplinary investigation identified the location, thickness, and potential impacts of wood-waste that has persisted in the nearshore environment of Thatcher Bay since at least 1942. We also provide a process to efficiently evaluate alternatives to remediate the impact of this historical disturbance and to potentially contribute to an increase of nearshore diversity and productivity at this site. Elements of this approach could inform restoration planning at similarly impacted sites throughout the region.

Physical characteristics of dungeness crab and halibut habitats in Glacier Bay

USGS Publications Warehouse

Cochrane, Guy R.; Carlson, Paul R.; Denny, Jane F.; Boyle, Michael E.; Taggart, S. James; Hooge, Philip N.

1998-01-01

In Glacier Bay National Park, Alaska there are ongoing studies of Dungeness Crab (Cancer magister) and Pacific Halibut (Hippoglosus stenolepis). Scientists of the United States Geological Survey (USGS) are attempting to ascertain life history, distribution, and abundance, and to determine the effects of commercial fishing in the park (Carlson et al., 1998). Statistical sampling studies suggest that seafloor characteristics and bathymetry affect the distribution, abundance and behavior of benthic species. Examples include the distribution of Dungeness crab which varies from 78 to 2012 crabs/ha in nearshore areas to depths of 18 m (O'Clair et al., 1995), and changes in halibut foraging behavior according to bottom type (Chilton et al., 1995). This report discusses geophysical data collected in six areas within the park in 1998. The geophysical surveying done in this and previous studies will be combined with existing population and sonic-tracking data sets as well as future sediment sampling, scuba, submersible, and bottom video camera observations to better understand Dungeness crab and Pacific halibut habitat relationships.

Physical characteristics of dungeness crab and halibut habitats in Whidbey Passage, Alaska

USGS Publications Warehouse

Cochrane, Guy R.; Carlson, Paul R.; Boyle, Michael E.; Gabel, Gregory L.; Hooge, Philip N.

2000-01-01

In Glacier Bay National Park, Alaska there are ongoing studies of Dungeness Crab (Cancer magister) and Pacific Halibut (Hippoglosus stenolepis). Scientists of the United States Geological Survey (USGS) are attempting to ascertain life history, distribution, and abundance, and to determine the effects of commercial fishing in the park (Carlson et al., 1998). Statistical sampling studies suggest that seafloor characteristics and bathymetry affect the distribution, abundance and behavior of benthic species. Examples include the distribution of Dungeness crab which varies from 78 to 2012 crabs/ha in nearshore areas to depths of 18 m (O'Clair et al., 1995), and changes in halibut foraging behavior according to bottom type (Chilton et al., 1995). This report discusses geophysical data collected within the park in 1998. The geophysical surveying done in this and previous studies will be combined with existing population and sonic-tracking data sets as well as future sediment sampling, scuba, submersible, and bottom video camera observations to better understand Dungeness crab and Pacific halibut habitat relationships.

The Horseshoe Crab of the Genus Limulus: Living Fossil or Stabilomorph?

PubMed Central

Błażejowski, Błażej

2014-01-01

A new horseshoe crab species, Limulus darwini, is described from the uppermost Jurassic (ca. 148 Ma) near-shore sediments of the Kcynia Formation, central Poland. The only extant species Limulus polyphemus (Linnaeus) inhabits brackish-marine, shallow water environments of the east coast of the United States. Here it is shown that there are no important morphological differences between the Kcynia Formation specimens and extant juvenile representatives of the genus Limulus. The palaeoecological setting inhabited by the new species and the trophic relationships of extant horseshoe crabs are discussed in an attempt to determine the potential range of food items ingested by these Mesozoic xiphosurans. In this paper we propose the adoption of a new term stabilomorphism, this being: an effect of a specific formula of adaptative strategy among organisms whose taxonomic status does not exceed genus-level. A high effectiveness of adaptation significantly reduces the need for differentiated phenotypic variants in response to environmental changes and provides for long-term evolutionary success. PMID:25275563

The use of ERTS-1 to more fully utilize and apply marine station data to the study and productivity along the eastern shelf waters of the United States

NASA Technical Reports Server (NTRS)

Marshall, H. G. (Principal Investigator); Bowker, D. E.; Witte, W. G.

1976-01-01

The author has identified the following significant results. Sea truth data were obtained during two ERTS overpasses in waters near the entrance of the Chesapeake Bay. Correlations were made between total phytoplankton and chlorophyll values in these waters to radiance detected by ERTS in an effort to map areas of similar productivity levels. Band 4 radiance had the highest correlation to all parameters with bands 5 and 6 showing decreasing correlations in each case. The radiance values were apparently influenced by one or more factors, most likely including the sediment content of the water. Data have shown that ERTS MSS is not suitable for monitoring chlorophyll in near-shore waters where sediment loads are high. It is suggested that in more seaward or pelagic locations, that ERTS MSS would be more efficient in monitoring surface chlorophyll values and establishing direct relationships to phytoplankton concentrations.

Coastal processes study at Ocean Beach, San Francisco, CA: summary of data collection 2004-2006

USGS Publications Warehouse

Barnard, Patrick L.; Eshleman, Jodi; Erikson, Li H.; Hanes, Daniel M.

2007-01-01

Ocean Beach in San Francisco, California, contains a persistent erosional section in the shadow of the San Francisco ebb tidal delta and south of Sloat Boulevard that threatens valuable public infrastructure as well as the safe recreational use of the beach. Coastal managers have been discussing potential mediation measures for over a decade, with little scientific research available to aid in decision making. The United States Geological Survey (USGS) initiated the Ocean Beach Coastal Processes Study in April 2004 to provide the scientific knowledge necessary for coastal managers to make informed management decisions. This study integrates a wide range of field data collection and numerical modeling techniques to document nearshore sediment transport processes at the mouth of San Francisco Bay, with emphasis on how these processes relate to erosion at Ocean Beach. The Ocean Beach Coastal Processes Study is the first comprehensive study of coastal processes at the mouth of San Francisco Bay.

Evaluating commercial marine emissions and their role in air quality policy using observations and the CMAQ model

NASA Astrophysics Data System (ADS)

Ring, Allison M.; Canty, Timothy P.; Anderson, Daniel C.; Vinciguerra, Timothy P.; He, Hao; Goldberg, Daniel L.; Ehrman, Sheryl H.; Dickerson, Russell R.; Salawitch, Ross J.

2018-01-01

We investigate the representation of emissions from the largest (Class 3) commercial marine vessels (c3 Marine) within the Community Multiscale Air Quality (CMAQ) model. In present emissions inventories developed by the United States Environmental Protection Agency (EPA), c3 Marine emissions are divided into off-shore and near-shore files. Off-shore c3 Marine emissions are vertically distributed within the atmospheric column, reflecting stack-height and plume rise. Near-shore c3 Marine emissions, located close to the US shoreline, are erroneously assumed to occur only at the surface. We adjust the near-shore c3 Marine emissions inventory by vertically distributing these emissions to be consistent with the off-shore c3 Marine inventory. Additionally, we remove near-shore c3 Marine emissions that overlap with off-shore c3 Marine emissions within the EPA files. The CMAQ model generally overestimates surface ozone (O3) compared to Air Quality System (AQS) site observations, with the largest discrepancies occurring near coastal waterways. We compare modeled O3 from two CMAQ simulations for June, July, and August (JJA) 2011 to surface O3 observations from AQS sites to examine the efficacy of the c3 Marine emissions improvements. Model results at AQS sites show average maximum 8-hr surface O3 decreases up to ∼6.5 ppb along the Chesapeake Bay, and increases ∼3-4 ppb around Long Island Sound, when the adjusted c3 Marine emissions are used. Along with the c3 Marine emissions adjustments, we reduce on-road mobile NOX emissions by 50%, motivated by work from Anderson et al. 2014, and reduce the lifetime of the alkyl nitrate species group from ∼10 days to ∼1 day based on work by Canty et al. 2015, to develop the ;c3 Science; model scenario. Simulations with these adjustments further improve model representation of the atmosphere. We calculate the ratio of column formaldehyde (HCHO) and tropospheric column nitrogen dioxide (NO2) using observations from the Ozone Monitoring Instrument and CMAQ model output to investigate the photochemical O3 production regime (VOC or NOX-limited) of the observed and modeled atmosphere. Compared to the baseline, the c3 Science model scenario more closely simulates the HCHO/NO2 ratio calculated from OMI data. Model simulations for JJA 2018 using the c3 Science scenario show a reduction of surface O3 by as much as ∼13 ppb for areas around the Chesapeake Bay and ∼2-3 ppb at locations in NY and CT downwind of New York City. These reductions are larger in 2018 than in 2011 due to a change in the photochemical O3 production regime in the Long Island Sound region and the projected decline of other (non-c3 Marine) sources of O3 precursors, highlighting the importance of proper representation of c3 Marine emissions in future modeling scenarios.

Influence of Cladophora-Quagga Mussel Assemblages on Nearshore Methylmercury Production in Lake Michigan.

PubMed

Lepak, Ryan F; Krabbenhoft, David P; Ogorek, Jacob M; Tate, Michael T; Bootsma, Harvey A; Hurley, James P

2015-07-07

Recent spread of invasive mussels in Lake Michigan has altered primary productivity in the nearshore zone, resulting in proliferation of filamentous benthic green algae (Cladophora glomerata). In areas of dense Cladophora and quagga mussel (Dreissena bugensis) assemblages, as well as in regions where sloughed Cladophora accumulates, methylmercury (MeHg) production is enhanced. A shoreline transect from a river mouth through waters overlying Cladophora/quagga-rich zones showed that aqueous MeHg concentrations increased, despite river dilution. Cladophora, as primary producers, ranged from 0.6 to 7.5 ng g(-1) MeHg [4-47% of total mercury (Hg) as MeHg], and were higher than MeHg concentrations in offshore-collected seston. Concentrations of MeHg in decaying Cladophora accumulated onshore ranged from 2.6 to 18.0 ng g(-1) MeHg (18-41% as MeHg) and from 0.1 to 3.0 ng g(-1) MeHg (2-21% as MeHg) in deposits of recently sloughed and accumulated Cladophora in a nearshore topographical depression. Relative to offshore open waters, interstitial waters within decaying Cladophora from onshore and nearshore deposits were elevated in MeHg concentration, 1000- and 10-fold, respectively. Percent Hg as MeHg was also elevated (65-75% and 9-19%, respectively for onshore interstitial water and nearshore interstitial water, compared to 0.2-3.3% as MeHg for open water). Quagga mussels collected within growing Cladophora beds in the nearshore zone were significantly higher in MeHg than offshore counterparts. Our combined results suggest that recent changes in nearshore primary production contributes to MeHg production and bioaccumulation in Lake Michigan.

Trace fossils and hummocky cross-stratification, upper Cretaceous of Utah

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

Frey, R.W.

The Spring Canyon Member of the Blackhawk Formation in Coal Creek Canyon, Utah, consists of four regressive nearshore-to-offshore sequences punctuated locally by hummocky cross-stratification. Collectively, nonstorm bedding units span lower offshore to middle shoreface lithofacies. Associated ichnofaunas tend to be diverse, distinctive, and diagnostic of original depositional gradients. Nevertheless, all resident ichnofaunas are referable to the Cruziana ichnocoenose. Ichnofaunas of hummocky beds, in contrast, mainly represent either a Skolithos ichnocoenose or a mixed Skolithos-Cruziana ichnocoenose. These post-storm ichnocoenoses evidently correspond to a sere of opportunistic pioneers or ensuing seres of resilient resident populations, although distal biocoenoses may have remained essentiallymore » beyond reach of prevalant nearshore opportunists. The predominance of domichnia over fodinichnia in initial post-storm ichnocoenoses probably reflects original larval settlement patterns tempered by gradients in hydraulic energy. Differences in ichnofaunas also are related to differences in rates of post-storm deposition: the slower the rate of sediment accumulation, the greater the degree of overprinting by burrows of subsequent seres or equilibrium communities.« less

Performance Monitoring of a Nearshore Berm at Ft. Myers Beach, Florida

DTIC Science & Technology

2013-08-01

prototype designs. Coastal Zone ’93, American Society of Civil Engineers, pp. 2938 -2950. Andrassy, C . J. 1991. Monitoring of a nearshore disposal mound at...ER D C / CH L TR -1 3 -1 1 Performance Monitoring of a Nearshore Berm at Ft. Myers Beach, Florida: Final Report C oa st al a n d H yd...122  Appendix C : USF-CRL Survey Data: morphologic evolution during the first 2 years post construction

Simulating Radionuclide Migrations of Low-level Wastes in Nearshore Environment

NASA Astrophysics Data System (ADS)

Lu, C. C.; Li, M. H.; Chen, J. S.; Yeh, G. T.

2016-12-01

Tunnel disposal into nearshore mountains was tentatively selected as one of final disposal sites for low-level wastes in Taiwan. Safety assessment on radionuclide migrations in far-filed may involve geosphere processes under coastal environments and into nearshore ocean. In this study the 3-D HYDROFEOCHE5.6 numerical model was used to perform simulations of groundwater flow and radionuclide transport with decay chains. Domain of interest on the surface includes nearby watersheds delineated by digital elevation models and nearshore seabed. As deep as 800 m below the surface and 400 m below sea bed were considered for simulations. The disposal site was located at 200m below the surface. Release rates of radionuclides from near-field was estimated by analytical solutions of radionuclide diffusion with decay out of engineered barriers. Far-field safety assessments were performed starting from the release of radionuclides out of engineered barriers to a time scale of 10,000 years. Sensitivity analyses of geosphere and transport parameters were performed to improve our understanding of safety on final disposal of low-level waste in nearshore environments.

Breakpoint-forced and bound long waves in the nearshore: A model comparison

USGS Publications Warehouse

List, Jeffrey H.; ,

1993-01-01

A finite-difference model is used to compare long wave amplitudes arising from two-group forced generation mechanisms in the nearshore: long waves generated at a time-varying breakpoint and the shallow-water extension of the bound long wave. Plane beach results demonstrate that the strong frequency selection in the outgoing wave predicted by the breakpoint-forcing mechanism may not be observable in field data due to this wave's relatively small size and its predicted phase relation with the bound wave. Over a bar/trough nearshore, it is shown that a strong frequency selection in shoreline amplitudes is not a unique result of the time-varying breakpoint model, but a general result of the interaction between topography and any broad-banded forcing of nearshore long waves.

Coastal nutrification and coral health at Porto Seguro reefs, Brazil

NASA Astrophysics Data System (ADS)

Costa, O.; Attrill, M.; Nimmo, M.

2003-04-01

Human activities have substantially increased the natural flux of nutrients to coastal systems worldwide. In Brazilian reefs, all major stresses (sedimentation, overfishing, tourism-related activities and nutrification) are human induced. To assess nutrification levels in Brazilian coastal reefs, measurements of the distribution patterns of nutrients and chlorophyll concentrations were conducted in three nearshore and offshore reefs with distinct nutrient inputs along the south coast of Bahia State. Seawater and porewater samples were analysed for soluble reactive phosphorus, total oxidised nitrogen and reactive silica. Benthic surveys were performed at all sites to investigate the relationships between benthic community composition and nutrient and chlorophyll concentrations. Sampling was undertaken in dry and rainy seasons. Results of both seawater and porewater nutrient measurements revealed the occurrence of consistent spatial and temporal patterns. An inshore-offshore gradient reflects the occurrence of land-based point sources, with significant amount of nutrients being delivered by human activities on the coast (untreated sewage and groundwater seepage). Another spatial gradient is related to distance from a localized source of pollution (an urban settlement without sewerage treatment) with two nearshore reefs presenting distinct nutrient and chlorophyll concentrations. Seasonal variations suggest that submarine groundwater discharge (SGD) is the primary source of nutrients for the coastal reefs during rainy season. The data also suggests that the SGD effect is not restricted to nearshore reefs, and may be an important factor controlling the differences between landward and seaward sides on the offshore reef. Benthic community assessment revealed that turf alga is the dominant group in all studied reefs and that zoanthids are the organisms most adapted to take advantage of nutrient increase in coastal areas. At nearshore reefs, there was a negative correlation between zoanthids and algal abundance and a positive correlation with the amount of available space for settlement. On the offshore reef, correlation of algal cover with both zoanthids and available space were negative, suggesting that hard substrate may be the primary limiting factor for algal settlement and growth in the nearshore reefs. Highly variable physical disturbances (like wave energy and low tide exposure) between landward and seaward reef sides appear to be the factors controlling algal distribution in the offshore reef. Highly spatial variability in coral cover ultimately reflects the patchy distribution of stony corals over the reefs.

Western Fisheries Research Center--Forage fish studies in Puget Sound

USGS Publications Warehouse

Liedtke, Theresa L.

2012-01-01

Researchers at the Western Fisheries Research Center are working with other U.S. Geological Survey (USGS) Centers to better understand the interconnected roles of forage fishes throughout the ecosystem of Puget Sound, Washington. Support for these studies primarily is from the USGS Coastal Habitats in Puget Sound (CHIPS) program, which supports studies of the nearshore areas of Puget Sound. Human perturbations in the nearshore area such as shoreline armoring or urban development can affect the nearshore habitats critical to forage fish.

Observing Migration and Burial of Unexploded Ordnance in the Nearshore Environment with Instrumented Surrogates

NASA Astrophysics Data System (ADS)

Bruder, B. L.; Cristaudo, D.; Puleo, J. A.

2016-12-01

Prior to 1972, it was legal and common practice to unload unexploded ordnance (UXO) into the ocean. Only 60-100 miles off the US coast alone there are 72 dumping sites where it is estimated 31 million pounds of UXO lie. As recently as 2015, UXO have been found not only in the nearshore environment, but on populated beaches. Thus, understanding the migration and burial of these objects is not only of oceanographic interest, but a matter of public safety. The presented project evaluates the efficacy of instrumented UXO surrogates for observing munition migration and burial. Instrumented surrogates were exposed to near prototype scale wave conditions over a mobile bed at the Littoral Warfare Environment at Aberdeen Test Center, MD. Surrogates were deployed in the swash zone, inner and outer surf zones. Dependent on munition size, surrogates housed multiple suites of self-logging sensors. Sensor suites included different combinations of inertial motion units, ultra-wideband tracking tags, pressure transducers, shock recorders, and photocells. Preliminary results show sensor suites can resolve various types of surrogate movement. Pressure transducers accurately record ambient wave conditions as well as changes in mean depth due to surrogate migration. Inertial motion units resolve munition accelerations for rolling and translational motion. Inertial motion unit data is used to estimate trajectory as well when coupled with mean depth and bathymetric data. Photocells, which measure ambient light, resolve munition burial as well as serve as proxies for surrounding environmental conditions such as suspended sediment and water depth. The presented project will continue to utilize and couple surrogate sensor data to resolve munition movement and burial under different conditions. Knowledge of munition migration helps focus UXO detection and recovery, conserving US military and coastal resources.

The Future of Nearshore Processes Research

NASA Astrophysics Data System (ADS)

Elko, N.; Feddersen, F.; Foster, D. L.; Holman, R. A.; McNinch, J.; Ozkan-Haller, H. T.; Plant, N. G.; Raubenheimer, B.; Elgar, S.; Hay, A. E.; Holland, K. T.; Kirby, J. T., Jr.; Lippmann, T. C.; Miller, J. K.; Stockdon, H. F.; Ashton, A. D.; Boehm, A. B.; Clark, D.; Cowen, E.; Dalyander, S.; Gelfenbaum, G. R.; Hapke, C. J.; MacMahan, J.; McNamara, D.; Mulligan, R. P.; Palmsten, M. L.; Ruggiero, P.; Sherwood, C. R.; Hsu, T. J.

2014-12-01

Over 70 members of the nearshore coastal processes research community convened in April 2014 to discuss a vision for the future of nearshore science while celebrating the memories and contributions of our recently departed colleague, Abby Sallenger. The participants reviewed community accomplishments over the past four decades. Federal agencies, including FEMA, NOAA, NPS, USGS, USACE, and NRL discussed the most pressing societal needs within the coastal zone. The group engaged in a retrospective of the last four decades of progress, assessed the current status and limitations of nearshore processes research, and developed a vision for the future that focuses on societally relevant problems. The top research topics identified included: Long-term Coastal Impacts: Meaningfully improve our understanding and prediction of the long-term coastal effects of sea level rise and changes in storminess patterns and associated efforts to protect coastal infrastructure. Extreme Events: Coastal flooding, overland flow, and concurrent morphological evolution during extreme events including the subsequent process of coastal recovery. Human and Ecosystem Health: Linkages between physical coastal processes (transport and mixing) and land-based pollution (pathogens, nutrients, toxic contaminants). Critical for addressing these research questions is enabling infrastructure, such as new observational tools and data sets, models, and nearshore-community communication and collaboration. Idea and concepts developed during the meeting (to be published in Shore and Beach) will be presented to foster collaboration and advocacy amongst the wider nearshore community. Meeting materials are available at: https://scripps.ucsd.edu/centers/nearshorefuture/.

Patterns in artisanal coral reef fisheries revealed through local monitoring efforts

PubMed Central

Teneva, Lida T.; Ogawa, Tom; Friedlander, Alan M.

2017-01-01

Sustainable fisheries management is key to restoring and maintaining ecological function and benefits to people, but it requires accurate information about patterns of resource use, particularly fishing pressure. In most coral reef fisheries and other data-poor contexts, obtaining such information is challenging and remains an impediment to effective management. We developed the most comprehensive regional view of shore-based fishing effort and catch published to date, to show detailed fishing patterns from across the main Hawaiian Islands (MHI). We reveal these regional patterns through fisher “creel” surveys conducted by local communities, state agencies, academics, and/or environmental organizations, at 18 sites, comprising >10,000 h of monitoring across a range of habitats and human influences throughout the MHI. All creel surveys included in this study except for one were previously published in some form (peer-reviewed articles or gray literature reports). Here, we synthesize these studies to document spatial patterns in nearshore fisheries catch, effort, catch rates (i.e., catch-per-unit-effort (CPUE)), and catch disposition (i.e., use of fish after catch is landed). This effort provides for a description of general regional patterns based on these location-specific studies. Line fishing was by far the dominant gear type employed. The most efficient gear (i.e., highest CPUE) was spear (0.64 kg h−1), followed closely by net (0.61 kg h−1), with CPUE for line (0.16 kg h−1) substantially lower than the other two methods. Creel surveys also documented illegal fishing activity across the studied locations, although these activities were not consistent across sites. Overall, most of the catch was not sold, but rather retained for home consumption or given away to extended family, which suggests that cultural practices and food security may be stronger drivers of fishing effort than commercial exploitation for coral reef fisheries in Hawai‘i. Increased monitoring of spatial patterns in nearshore fisheries can inform targeted management, and can help communities develop a more informed understanding of the drivers of marine resource harvest and the state of the resources, in order to maintain these fisheries for food security, cultural practices, and ecological value. PMID:29226033

Long-term nutrient reductions lead to the unprecedented recovery of a temperate coastal region.

PubMed

Lefcheck, Jonathan S; Orth, Robert J; Dennison, William C; Wilcox, David J; Murphy, Rebecca R; Keisman, Jennifer; Gurbisz, Cassie; Hannam, Michael; Landry, J Brooke; Moore, Kenneth A; Patrick, Christopher J; Testa, Jeremy; Weller, Donald E; Batiuk, Richard A

2018-04-03

Humans strongly impact the dynamics of coastal systems, yet surprisingly few studies mechanistically link management of anthropogenic stressors and successful restoration of nearshore habitats over large spatial and temporal scales. Such examples are sorely needed to ensure the success of ecosystem restoration efforts worldwide. Here, we unite 30 consecutive years of watershed modeling, biogeochemical data, and comprehensive aerial surveys of Chesapeake Bay, United States to quantify the cascading effects of anthropogenic impacts on submersed aquatic vegetation (SAV), an ecologically and economically valuable habitat. We employ structural equation models to link land use change to higher nutrient loads, which in turn reduce SAV cover through multiple, independent pathways. We also show through our models that high biodiversity of SAV consistently promotes cover, an unexpected finding that corroborates emerging evidence from other terrestrial and marine systems. Due to sustained management actions that have reduced nitrogen concentrations in Chesapeake Bay by 23% since 1984, SAV has regained 17,000 ha to achieve its highest cover in almost half a century. Our study empirically demonstrates that nutrient reductions and biodiversity conservation are effective strategies to aid the successful recovery of degraded systems at regional scales, a finding which is highly relevant to the utility of environmental management programs worldwide.

Efficient Data Assimilation Algorithms for Bathymetry Applications

NASA Astrophysics Data System (ADS)

Ghorbanidehno, H.; Kokkinaki, A.; Lee, J. H.; Farthing, M.; Hesser, T.; Kitanidis, P. K.; Darve, E. F.

2016-12-01

Information on the evolving state of the nearshore zone bathymetry is crucial to shoreline management, recreational safety, and naval operations. The high cost and complex logistics of using ship-based surveys for bathymetry estimation have encouraged the use of remote sensing monitoring. Data assimilation methods combine monitoring data and models of nearshore dynamics to estimate the unknown bathymetry and the corresponding uncertainties. Existing applications have been limited to the basic Kalman Filter (KF) and the Ensemble Kalman Filter (EnKF). The former can only be applied to low-dimensional problems due to its computational cost; the latter often suffers from ensemble collapse and uncertainty underestimation. This work explores the use of different variants of the Kalman Filter for bathymetry applications. In particular, we compare the performance of the EnKF to the Unscented Kalman Filter and the Hierarchical Kalman Filter, both of which are KF variants for non-linear problems. The objective is to identify which method can better handle the nonlinearities of nearshore physics, while also having a reasonable computational cost. We present two applications; first, the bathymetry of a synthetic one-dimensional cross section normal to the shore is estimated from wave speed measurements. Second, real remote measurements with unknown error statistics are used and compared to in situ bathymetric survey data collected at the USACE Field Research Facility in Duck, NC. We evaluate the information content of different data sets and explore the impact of measurement error and nonlinearities.

The Role of Nearshore Ecosystems as Fish and Shellfish Nurseries

EPA Pesticide Factsheets

The module provides a link to an article that is part of a series of articles in Issues in Ecology. This article provides information on the necessity to protect nearshore habitats that serve as nurseries.

The Fate and Impact of Internal Waves in Nearshore Ecosystems

NASA Astrophysics Data System (ADS)

Woodson, C. B.

2018-01-01

Internal waves are widespread features of global oceans that play critical roles in mixing and thermohaline circulation. Similarly to surface waves, internal waves can travel long distances, ultimately breaking along continental margins. These breaking waves can transport deep ocean water and associated constituents (nutrients, larvae, and acidic low-oxygen waters) onto the shelf and locally enhance turbulence and mixing, with important effects on nearshore ecosystems. We are only beginning to understand the role internal waves play in shaping nearshore ecosystems. Here, I review the physics of internal waves in shallow waters and identify two commonalities among internal waves in the nearshore: exposure to deep offshore waters and enhanced turbulence and mixing. I relate these phenomena to important ecosystem processes ranging from extreme events to fertilization success to draw general conclusions about the influence of internal waves on ecosystems and the effects of internal waves in a changing climate.

A nearshore processes field experiment at Cape Hatteras, North Carolina, U.S.A.

USGS Publications Warehouse

List, Jeffrey H.; Warner, John C.; Thieler, E. Robert; Haas, Kevin; Voulgaris, George; McNinch, Jesse E.; Brodie, Katherine L.; Rosati, Julie D.; Wang, Ping; Roberts, Tiffany M.

2011-01-01

A month-long field experiment focused on the nearshore hydrodynamics of Diamond Shoals adjacent to Cape Hatteras Point, North Carolina, was conducted in February 2010. The objectives of this multi-institutional experiment were to test hypotheses related to Diamond Shoals as a sink in the regional sediment budget and to provide data for evaluating numerical models. The experiment included in-situ instrumentation for measuring waves and currents; a video camera system for measuring surface currents at a nearshore transect; a radar system for measuring regional surface currents over Diamond Shoals and the adjacent coast; a vehicle-based scanning lidar and radar system for mapping beach topography, nearshore wave breaking intensity, bathymetry (through wave celerity inversion), and wave direction; and an amphibious vehicle system for surveying single-beam bathymetry. Preliminary results from wave and current measurements suggest that shoal-building processes were active during the experiment.

The Fate and Impact of Internal Waves in Nearshore Ecosystems.

PubMed

Woodson, C B

2018-01-03

Internal waves are widespread features of global oceans that play critical roles in mixing and thermohaline circulation. Similarly to surface waves, internal waves can travel long distances, ultimately breaking along continental margins. These breaking waves can transport deep ocean water and associated constituents (nutrients, larvae, and acidic low-oxygen waters) onto the shelf and locally enhance turbulence and mixing, with important effects on nearshore ecosystems. We are only beginning to understand the role internal waves play in shaping nearshore ecosystems. Here, I review the physics of internal waves in shallow waters and identify two commonalities among internal waves in the nearshore: exposure to deep offshore waters and enhanced turbulence and mixing. I relate these phenomena to important ecosystem processes ranging from extreme events to fertilization success to draw general conclusions about the influence of internal waves on ecosystems and the effects of internal waves in a changing climate.

Remote sensing of Qatar nearshore habitats with perspectives for coastal management.

PubMed

Warren, Christopher; Dupont, Jennifer; Abdel-Moati, Mohamed; Hobeichi, Sanaa; Palandro, David; Purkis, Sam

2016-04-30

A framework is proposed for utilizing remote sensing and ground-truthing field data to map benthic habitats in the State of Qatar, with potential application across the Arabian Gulf. Ideally the methodology can be applied to optimize the efficiency and effectiveness of mapping the nearshore environment to identify sensitive habitats, monitor for change, and assist in management decisions. The framework is applied to a case study for northeastern Qatar with a key focus on identifying high sensitivity coral habitat. The study helps confirm the presence of known coral and provides detail on a region in the area of interest where corals have not been previously mapped. Challenges for the remote sensing methodology associated with natural heterogeneity of the physical and biological environment are addressed. Recommendations on the application of this approach to coastal environmental risk assessment and management planning are discussed as well as future opportunities for improvement of the framework. Copyright © 2015 Elsevier Ltd. All rights reserved.

Modeling the impacts of wildfire on runoff and pollutant transport from coastal watersheds to the nearshore environment.

PubMed

Morrison, Katherine D; Kolden, Crystal A

2015-03-15

Wildfire is a common disturbance that can significantly alter vegetation in watersheds and affect the rate of sediment and nutrient transport to adjacent nearshore oceanic environments. Changes in runoff resulting from heterogeneous wildfire effects are not well-understood due to both limitations in the field measurement of runoff and temporally-limited spatial data available to parameterize runoff models. We apply replicable, scalable methods for modeling wildfire impacts on sediment and nonpoint source pollutant export into the nearshore environment, and assess relationships between wildfire severity and runoff. Nonpoint source pollutants were modeled using a GIS-based empirical deterministic model parameterized with multi-year land cover data to quantify fire-induced increases in transport to the nearshore environment. Results indicate post-fire concentration increases in phosphorus by 161 percent, sediments by 350 percent and total suspended solids (TSS) by 53 percent above pre-fire years. Higher wildfire severity was associated with the greater increase in exports of pollutants and sediment to the nearshore environment, primarily resulting from the conversion of forest and shrubland to grassland. This suggests that increasing wildfire severity with climate change will increase potential negative impacts to adjacent marine ecosystems. The approach used is replicable and can be utilized to assess the effects of other types of land cover change at landscape scales. It also provides a planning and prioritization framework for management activities associated with wildfire, including suppression, thinning, and post-fire rehabilitation, allowing for quantification of potential negative impacts to the nearshore environment in coastal basins. Copyright © 2014 Elsevier Ltd. All rights reserved.

Predictive Modelling to Identify Near-Shore, Fine-Scale Seabird Distributions during the Breeding Season

PubMed Central

Warwick-Evans, Victoria C.; Atkinson, Philip W.; Robinson, Leonie A.; Green, Jonathan A.

2016-01-01

During the breeding season seabirds are constrained to coastal areas and are restricted in their movements, spending much of their time in near-shore waters either loafing or foraging. However, in using these areas they may be threatened by anthropogenic activities such as fishing, watersports and coastal developments including marine renewable energy installations. Although many studies describe large scale interactions between seabirds and the environment, the drivers behind near-shore, fine-scale distributions are not well understood. For example, Alderney is an important breeding ground for many species of seabird and has a diversity of human uses of the marine environment, thus providing an ideal location to investigate the near-shore fine-scale interactions between seabirds and the environment. We used vantage point observations of seabird distribution, collected during the 2013 breeding season in order to identify and quantify some of the environmental variables affecting the near-shore, fine-scale distribution of seabirds in Alderney’s coastal waters. We validate the models with observation data collected in 2014 and show that water depth, distance to the intertidal zone, and distance to the nearest seabird nest are key predictors in the distribution of Alderney’s seabirds. AUC values for each species suggest that these models perform well, although the model for shags performed better than those for auks and gulls. While further unexplained underlying localised variation in the environmental conditions will undoubtedly effect the fine-scale distribution of seabirds in near-shore waters we demonstrate the potential of this approach in marine planning and decision making. PMID:27031616

Strongly-sheared wind-forced currents in the nearshore regions of the central Southern California Bight

USGS Publications Warehouse

Noble, Marlene A.; Rosenberger, Kurt; Robertson, George L.

2015-01-01

Contrary to many previous reports, winds do drive currents along the shelf in the central portion of the Southern California Bight (SCB). Winds off Huntington Beach CA are the dominant forcing for currents over the nearshore region of the shelf (water depths less than 20 m). Winds control about 50–70% of the energy in nearshore alongshelf surface currents. The wind-driven current amplitudes are also anomalously high. For a relatively weak 1 dyne/cm2 wind stress, the alongshelf surface current amplitudes in this region can reach 80 cm/s or more. Mid-depth current amplitudes for the same wind stress are around 30–40 cm/s. These wind-driven surface current amplitudes are much larger than previously measured over other nearshore shelf regions, perhaps because this program is one of the few that measured currents within a meter of the surface. The near-bed cross-shelf currents over the nearshore region of the Huntington Beach shelf have an Ekman response to winds in that they upwell (downwell) for down (up) coast winds. This response disappears further offshore. Hence, there is upwelling in the SCB, but it does not occur across the entire shelf. Subthermocline water in the nearshore region that may contain nutrients and plankton move onshore when winds are southeastward, but subthermocline water over the shelf break is not transported to the beach. The currents over the outer shelf are not predominately controlled by winds, consistent with previous reports. Instead, they are mainly driven by cross-shelf pressure gradients that are independent of local wind stress.

Tools and methods for evaluating and refining alternative futures for coastal ecosystem management—the Puget Sound Ecosystem Portfolio Model

USGS Publications Warehouse

Byrd, Kristin B.; Kreitler, Jason R.; Labiosa, William B.

2011-01-01

The U.S. Geological Survey Puget Sound Ecosystem Portfolio Model (PSEPM) is a decision-support tool that uses scenarios to evaluate where, when, and to what extent future population growth, urban growth, and shoreline development may threaten the Puget Sound nearshore environment. This tool was designed to be used iteratively in a workshop setting in which experts, stakeholders, and decisionmakers discuss consequences to the Puget Sound nearshore within an alternative-futures framework. The PSEPM presents three possible futures of the nearshore by analyzing three growth scenarios developed out to 2060: Status Quo—continuation of current trends; Managed Growth—adoption of an aggressive set of land-use management policies; and Unconstrained Growth—relaxation of land-use restrictions. The PSEPM focuses on nearshore environments associated with barrier and bluff-backed beaches—the most dominant shoreforms in Puget Sound—which represent 50 percent of Puget Sound shorelines by length. This report provides detailed methodologies for development of three submodels within the PSEPM—the Shellfish Pollution Model, the Beach Armoring Index, and the Recreation Visits Model. Results from the PSEPM identify where and when future changes to nearshore ecosystems and ecosystem services will likely occur within the three growth scenarios. Model outputs include maps that highlight shoreline sections where nearshore resources may be at greater risk from upland land-use changes. The background discussed in this report serves to document and supplement model results displayed on the PSEPM Web site located at http://geography.wr.usgs.gov/pugetSound/.

Nearshore sediment thickness, Fire Island, New York

USGS Publications Warehouse

Locker, Stanley D.; Miselis, Jennifer L.; Buster, Noreen A.; Hapke, Cheryl J.; Wadman, Heidi M.; McNinch, Jesse E.; Forde, Arnell S.; Stalk, Chelsea A.

2017-04-03

Investigations of coastal change at Fire Island, New York (N.Y.), sought to characterize sediment budgets and determine geologic framework controls on coastal processes. Nearshore sediment thickness is critical for assessing coastal system sediment availability, but it is largely unquantified due to the difficulty of conducting geological or geophysical surveys across the nearshore. This study used an amphibious vessel to acquire chirp subbottom profiles. These profiles were used to characterize nearshore geology and provide an assessment of nearshore sediment volume. Two resulting sediment-thickness maps are provided: total Holocene sediment thickness and the thickness of the active shoreface. The Holocene sediment section represents deposition above the maximum flooding surface that is related to the most recent marine transgression. The active shoreface section is the uppermost Holocene sediment, which is interpreted to represent the portion of the shoreface thought to contribute to present and future coastal behavior. The sediment distribution patterns correspond to previously defined zones of erosion, accretion, and stability along the island, demonstrating the importance of sediment availability in the coastal response to storms and seasonal variability. The eastern zone has a thin nearshore sediment thickness, except for an ebb-tidal deposit at the wilderness breach caused by Hurricane Sandy. Thicker sediment is found along a central zone that includes shoreface-attached sand ridges, which is consistent with a stable or accretional coastline in this area. The thickest overall Holocene section is found in the western zone of the study, where a thicker lower section of Holocene sediment appears related to the westward migration of Fire Island Inlet over several hundred years.

Internal structures of the nieuwpoort bank (southern north sea)

NASA Astrophysics Data System (ADS)

de Maeyer, P.; Wartel, S.; de Moor, G.

The subbottom survey of the Nieuwpoort Banks allows recognition of 4 successive stages underlain by leper Clay: (1) The bank rests upon a sedimentary unit, at least 2 to 5 m thick, having a subhorizontal or wedge-like interior stratification. (2) This unit is cut by a subhorizontal erosive surface. (3) On top of this a first ridge, still recognizable on its interior structure and with shoreward-dipping foreset beds, developed. (4) On top of this former ridge the present-day bank was formed with shoreward-dipping foreset beds. Since the same structures are observed in the Stroom Bank, it seems likely that the above mentioned scheme can be generalized for all near-shore ridges close to the Belgian coast.

Plants as indicators of focused ground water discharge to a northern Minnesota lake

USGS Publications Warehouse

Rosenberry, D.O.; Striegl, Robert G.; Hudson, D.C.

2000-01-01

Determining the discharge of ground water to Shingobee Lake (66 ha), north-central Minnesota, is complicated by the presence of numerous springs situated adjacent to the lake and in the shallow portion of the lakebed. Springs first had to be located before these areas of more rapid discharge could be quantified. Two methods that rely on the distribution of aquatic plants are useful for locating springs. One method identifies areas of the near-shore lakebed where floating-leaf and emergent aquatic vegetation are absent. The second method uses the distribution of marsh marigold (Caltha palustris L.) to locate springs that discharge on land near the shoreline of the lake. Marsh marigold produces large (2 to 4 cm diameter) yellow flowers that provide a ready marker for locating ground water springs. Twice as many springs (38) were identified using this method as were identified using the lack of near-shore vegetation. A portable weir was used to measure discharge from onshore springs, and seepage meters were used to measure discharge from near-shore springs. Of the total 56.7 L s-1 that enters the lake from ground water, approximately 30% comes from onshore and near-shore springs.Determining the discharge of ground water to Shingobee Lake (66 ha), north-central Minnesota, is complicated by the presence of numerous springs situated adjacent to the lake and in the shallow portion of the lakebed. Springs first had to be located before these areas of more rapid discharge could be quantified. Two methods that rely on the distribution of aquatic plants are useful for locating springs. One method identifies areas of the near-shore lakebed where floating-leaf and emergent aquatic vegetation are absent. The second method uses the distribution of marsh marigold (Caltha palustris L.) to locate springs that discharge on land near the shoreline of the lake. Marsh marigold produces large (2 to 4 cm diameter) yellow flowers that provide a ready marker for locating ground water springs. Twice as many springs (38) were identified using this method as were identified using the lack of near-shore vegetation. A portable weir was used to measure discharge from onshore springs, and seepage meters were used to measure discharge from near-shore springs. Of the total 56.7 L s-1 that enters the lake from ground water, approximately 30% comes from onshore and near-shore springs.

Lake Ontario: Nearshore Variability

EPA Science Inventory

We conducted a high-resolution survey with towed electronic instrumentation along the Lake Ontario nearshore (720 km) at a 20 meter contour. The survey was conducted September 6-10, 2008 with a shorter 300 km survey conducted August 14-15 for comparing of temporal variability. ...

Biogeography of Nearshore Subtidal Invertebrates in the Gulf of Maine

EPA Science Inventory

The biogeography of nearshore benthic invertebrates in the Gulf of Maine was studied to compare recent data with historical biogeographic studies, define physical-chemical factors affecting species distributions, and provide information needed to calibrate benthic indices of envi...

DEEPWATER AND NEARSHORE FOOD WEB CHARACTERIZATIONS IN LAKE SUPERIOR

EPA Science Inventory

Due to the difficulty associated with sampling deep aquatic systems, food web relationships among deepwater fauna are often poorly known. We are characterizing nearshore versus offshore habitats in the Great Lakes and investigating food web linkages among profundal, pelagic, and ...

Land-use planning for nearshore ecosystem services—the Puget Sound Ecosystem Portfolio Model

USGS Publications Warehouse

Byrd, Kristin

2011-01-01

The 2,500 miles of shoreline and nearshore areas of Puget Sound, Washington, provide multiple benefits to people—"ecosystem services"—including important fishing, shellfishing, and recreation industries. To help resource managers plan for expected growth in coming decades, the U.S. Geological Survey Western Geographic Science Center has developed the Puget Sound Ecosystem Portfolio Model (PSEPM). Scenarios of urban growth and shoreline modifications serve as model inputs to develop alternative futures of important nearshore features such as water quality and beach habitats. Model results will support regional long-term planning decisions for the Puget Sound region.

Winds and the distribution of nearshore phytoplankton in a stratified lake.

PubMed

Cyr, Hélène

2017-10-01

The distribution of phytoplankton in lakes is notoriously patchy and dynamic, but wind-driven currents and algal buoyancy/motility are thought to determine where algae accumulate. In this study, nearshore phytoplankton were sampled from different parts of a lake basin twice a day for 4-5 consecutive days, in the spring and in late summer, to test whether short-term changes in phytoplankton biomass and community composition can be predicted from wind-driven currents. On windy days, phytoplankton biomass was higher at downwind than at upwind nearshore sites, and the magnitude of this difference increased linearly with increasing wind speed. However, contrary to the generally assumed downwind phytoplankton aggregations, these differences were mostly due to upwelling activity and the dilution of phytoplankton at upwind nearshore sites. The distribution of individual taxa was also related to wind speed, but only during late stratification (except for cryptophytes), and these relationships were consistent with the buoyancy and motility of each group. On windy days, large diatoms and cyanobacteria concentrated upwind, neutrally buoyant taxa (green algae, small diatoms) were homogeneously distributed, and motile taxa (cryptophytes, chrysophytes, dinoflagellates) concentrated downwind. Predictable differences in the biomass and composition of phytoplankton communities could affect the efficiency of trophic transfers in nearshore areas. Copyright © 2017 Elsevier Ltd. All rights reserved.

A Nested Nearshore Nutrient Model (N&Sup3;M) for ...

EPA Pesticide Factsheets

Nearshore conditions drive phenomena like harmful algal blooms (HABs), and the nearshore and coastal margin are the parts of the Great Lakes most used by humans. To assess conditions, optimize monitoring, and evaluate management options, a model of nearshore nutrient transport and algal dynamics is being developed. The model targets a “regional” spatial scale, similar to the Great Lakes Aquatic Habitat Framework's sub-basins, which divide the nearshore into 30 regions. Model runs are 365 days, a whole season temporal scale, reporting at 3 hour intervals. N³M uses output from existing hydrodynamic models and simple transport kinetics. The nutrient transport component of this model is largely complete, and is being tested with various hydrodynamic data sets. The first test case covers a 200 km² area between two major tributaries to Lake Michigan, the Grand and Muskegon. N³M currently simulates phosphorous and chloride, selected for their distinct in-lake transport dynamics; nitrogen will be added. Initial results for 2003, 2010, and 2015 show encouraging correlations with field measurements. Initially implemented in MatLab, the model is currently implemented in Python and leverages multi-processor computation. The 4D in-browser visualizer Cesium is used to view model output, time varying satellite imagery, and field observations. not applicable

Near-shore Antarctic pH variability has implications for the design of ocean acidification experiments

PubMed Central

Kapsenberg, Lydia; Kelley, Amanda L.; Shaw, Emily C.; Martz, Todd R.; Hofmann, Gretchen E.

2015-01-01

Understanding how declining seawater pH caused by anthropogenic carbon emissions, or ocean acidification, impacts Southern Ocean biota is limited by a paucity of pH time-series. Here, we present the first high-frequency in-situ pH time-series in near-shore Antarctica from spring to winter under annual sea ice. Observations from autonomous pH sensors revealed a seasonal increase of 0.3 pH units. The summer season was marked by an increase in temporal pH variability relative to spring and early winter, matching coastal pH variability observed at lower latitudes. Using our data, simulations of ocean acidification show a future period of deleterious wintertime pH levels potentially expanding to 7–11 months annually by 2100. Given the presence of (sub)seasonal pH variability, Antarctica marine species have an existing physiological tolerance of temporal pH change that may influence adaptation to future acidification. Yet, pH-induced ecosystem changes remain difficult to characterize in the absence of sufficient physiological data on present-day tolerances. It is therefore essential to incorporate natural and projected temporal pH variability in the design of experiments intended to study ocean acidification biology.

Occurrence of flow parallel and flow transverse bedforms in Fehmarn Belt (SW Baltic Sea) related to the local palaeomorphology

NASA Astrophysics Data System (ADS)

Feldens, P.; Diesing, M.; Schwarzer, K.; Heinrich, C.; Schlenz, B.

2015-02-01

This study describes the spatial distribution of flow-parallel sand ribbons and flow-transverse large and very large subaqueous dunes in the south-western Baltic Sea offshore Fehmarn Island between 13 m and 20 m water depth, based on hydroacoustic and grain size data. The system of sand ribbons and dunes is intermittently active due to currents induced during major inflows of the North Sea water into the Baltic Sea. The sand ribbons are located on a lag deposit on top of glacial till, while the dunes rest on top of drowned Holocene nearshore deposits. The sand ribbons reach heights between 0.4 m and 0.6 m, with widths varying between 60 m and several hundreds of metres. The observed dunes have heights between 0.09 m and 2.35 m, while their wavelengths range from 17 m to 120 m. Offshore Fehmarn Island, the transition from sand ribbons to dunes is most likely linked to a contrast in sediment supply, as reworked drowned nearshore deposits provide sediment available for transport in significantly larger amounts than glacial till. Similar to an earlier approach for river bed states, the dimensionless thickness of sediment available for transport is able to differentiate between the bed states.

Lake Michigan: Nearshore Variability

EPA Science Inventory

We conducted a high-resolution survey in the nearshore of Lake Michigan at a 20 meter contour using towed electronic instrumentation. The nearly 1200 km survey was conducted Sep 8-15, 2010. We also conducted six cross-contour tows. Along the survey tracks we sampled fixed stat...

Moderate-Resolution Sea Surface Temperature Data for the Nearshore North Pacific

EPA Science Inventory

Coastal sea surface temperature (SST) is an important environmental characteristic defining habitat suitability for nearshore marine and estuarine organisms. The purpose of this publication is to provide access to an easy-to-use coastal SST dataset for ecologists, biogeographers...

Synthesis study of an erosion hot spot, Ocean Beach, California

USGS Publications Warehouse

Barnard, Patrick L.; Hansen, Jeff E.; Erikson, Li H.

2012-01-01

A synthesis of multiple coastal morphodynamic research efforts is presented to identify the processes responsible for persistent erosion along a 1-km segment of 7-km-long Ocean Beach in San Francisco, California. The beach is situated adjacent to a major tidal inlet and in the shadow of the ebb-tidal delta at the mouth of San Francisco Bay. Ocean Beach is exposed to a high-energy wave climate and significant alongshore variability in forcing introduced by varying nearshore bathymetry, tidal forcing, and beach morphology (e.g., beach variably backed by seawall, dunes, and bluffs). In addition, significant regional anthropogenic factors have influenced sediment supply and tidal current strength. A variety of techniques were employed to investigate the erosion at Ocean Beach, including historical shoreline and bathymetric analysis, monthly beach topographic surveys, nearshore and regional bathymetric surveys, beach and nearshore grain size analysis, two surf-zone hydrodynamic experiments, four sets of nearshore wave and current experiments, and several numerical modeling approaches. Here, we synthesize the results of 7 years of data collection to lay out the causes of persistent erosion, demonstrating the effectiveness of integrating an array of data sets covering a huge range of spatial scales. The key findings are as follows: anthropogenic influences have reduced sediment supply from San Francisco Bay, leading to pervasive contraction (i.e., both volume and area loss) of the ebb-tidal delta, which in turn reduced the regional grain size and modified wave focusing patterns along Ocean Beach, altering nearshore circulation and sediment transport patterns. In addition, scour associated with an exposed sewage outfall pipe causes a local depression in wave heights, significantly modifying nearshore circulation patterns that have been shown through modeling to be key drivers of persistent erosion in that area.

Monitoring in the nearshore: A process for making reasoned decisions

USGS Publications Warehouse

Bodkin, James L.; Dean, T.A.

2003-01-01

Over the past several years, a conceptual framework for the GEM nearshore monitoring program has been developed through a series of workshops. However, details of the proposed monitoring program, e.g. what to sample, where to sample, when to sample and at how many sites, have yet to be determined. In FY 03 we were funded under Project 03687 to outline a process whereby specific alternatives to monitoring are developed and presented to the EVOS Trustee Council for consideration. As part of this process, two key elements are required before reasoned decisions can be made. These are: 1) a comprehensive historical perspective of locations and types of past studies conducted in the nearshore marine communities within Gulf of Alaska, and 2) estimates of costs for each element of a proposed monitoring program. We have developed a GIS database that details available information from past studies of selected nearshore habitats and species in the Gulf of Alaska and provide a visual means of selecting sites based (in part) on the locations for which historical data of interest are available. We also provide cost estimates for specific monitoring plan alternatives and outline several alternative plans that can be accomplished within reasonable budgetary constraints. The products that we will provide are: 1) A GIS database and maps showing the location and types of information available from the nearshore in the Gulf of Alaska; 2) A list of several specific monitoring alternatives that can be conducted within reasonable budgetary constraints; and 3) Cost estimates for proposed tasks to be conducted as part of the nearshore program. Because data compilation and management will not be completed until late in FY03 we are requesting support for close-out of this project in FY 04.

Palaeoecological records of coral community development on a turbid, nearshore reef complex: baselines for assessing ecological change

NASA Astrophysics Data System (ADS)

Johnson, J. A.; Perry, C. T.; Smithers, S. G.; Morgan, K. M.; Santodomingo, N.; Johnson, K. G.

2017-09-01

Understanding past coral community development and reef growth is crucial for placing contemporary ecological and environmental change within appropriate reef-building timescales. On Australia's Great Barrier Reef (GBR), coral reefs situated within coastal inner-shelf zones are a particular priority. This is due to their close proximity to river point sources, and therefore susceptibility to reduced water quality discharged from coastal catchments, many of which have been modified following European settlement (ca. 1850 AD). However, the extent of water-quality decline and its impacts on the GBR's inner-shelf reefs remain contentious. In this study, palaeoecological coral assemblage records were developed for five proximal coral reefs situated within a nearshore turbid-zone reef complex on the central GBR. A total of 29 genera of Scleractinia were identified from the palaeoecological inventory of the reef complex, with key contributions to reef-building made by Acropora, Montipora, and Turbinaria. Discrete intervals pre- and post-dating European settlement, but associated with equivalent water depths, were identified using Bayesian age-depth modelling, enabling investigation of competing ideas of the main drivers of nearshore coral assemblage change. Specifically, we tested the hypotheses that changes in the composition of nearshore coral assemblages are: (1) intrinsically driven and linked to vertical reef development towards sea level, and (2) the result of changes in water quality associated with coastal river catchment modification. Our records found no discernible evidence of change in the generic composition of coral assemblages relative to European settlement. Instead, two distinctive depth-stratified assemblages were identified. This study demonstrates the robust nature of nearshore coral communities under reported water-quality decline and provides a useful context for the monitoring and assessment of ecological change on reefs located within the most nearshore turbid-zone environments of the central GBR.

Sources of land-derived runoff to a coral reef-fringed embayment identified using geochemical tracers in nearshore sediment traps

USGS Publications Warehouse

Takesue, Renee K.; Bothner, Michael H.; Reynolds, Richard L.

2009-01-01

Geochemical tracers, including Ba, Co, Th, 7Be, 137Cs and 210Pb, and magnetic properties were used to characterize terrestrial runoff collected in nearshore time-series sediment traps in Hanalei Bay, Kauai, during flood and dry conditions in summer 2006, and to fingerprint possible runoff sources in the lower watershed. In combination, the tracers indicate that runoff during a flood in August could have come from cultivated taro fields bordering the lower reach of the river. Land-based runoff associated with summer floods may have a greater impact on coral reef communities in Hanalei Bay than in winter because sediment persists for several months. During dry periods, sediment carried by the Hanalei River appears to have been mobilized primarily by undercutting of low 7Be, low 137Cs riverbanks composed of soil weathered from tholeiitic basalt with low Ba and Co concentrations. Following a moderate rainfall event in September, high 7Be sediment carried by the Hanalei River was probably mobilized by overland flow in the upper watershed. Ba-desorption in low-salinity coastal water limited its use to a qualitative runoff tracer in nearshore sediment. 210Pb had limited usefulness as a terrestrial tracer in the nearshore due to a large dissolved oceanic source and scavenging onto resuspended bottom sediment. 210Pb-scavenging does, however, illustrate the role resuspension could play in the accumulation of particle-reactive contaminants in nearshore sediment. Co and 137Cs were not affected by desorption or geochemical scavenging and showed the greatest potential as quantitative sediment provenance indicators in material collected in nearshore sediment traps.

Benthic foraminifera baseline assemblages from a coastal nearshore reef complex on the central Great Barrier Reef

NASA Astrophysics Data System (ADS)

Johnson, Jamie; Perry, Chris; Smithers, Scott; Morgan, Kyle

2016-04-01

Declining water quality due to river catchment modification since European settlement (c. 1850 A.D.) represents a major threat to the health of coral reefs on Australia's Great Barrier Reef (GBR), particularly for those located in the coastal waters of the GBR's inner-shelf. These nearshore reefs are widely perceived to be most susceptible to declining water quality owing to their close proximity to river point sources. Despite this, nearshore reefs have been relatively poorly studied with the impacts and magnitudes of environmental degradation still remaining unclear. This is largely due to ongoing debates concerning the significance of increased sediment yields against naturally high background sedimentary regimes. Benthic foraminifera are increasingly used as tools for monitoring environmental and ecological change on coral reefs. On the GBR, the majority of studies have focussed on the spatial distributions of contemporary benthic foraminiferal assemblages. While baseline assemblages from other environments (e.g. inshore reefs and mangroves) have been described, very few records exist for nearshore reefs. Here, we present preliminary results from the first palaeoecological study of foraminiferal assemblages of nearshore reefs on the central GBR. Cores were recovered from the nearshore reef complex at Paluma Shoals using percussion techniques. Recovery was 100%, capturing the entire Holocene reef sequence of the selected reef structures. Radiocarbon dating and subsequent age-depth modelling techniques were used to identify reef sequences pre-dating European settlement. Benthic foraminifera assemblages were reconstructed from the identified sequences to establish pre-European ecological baselines with the aim of providing a record of foraminiferal distribution during vertical reef accretion and against which contemporary ecological change may be assessed.

Inland and Near-Shore Water Profiles Derived from the High-Altitude Multiple Altimeter Beam Experimental Lidar (MABEL)

NASA Technical Reports Server (NTRS)

Jasinski, Michael F.; Stoll, Jeremy D.; Cook, William B.; Ondrusek, Michael; Stengel, Eric; Brunt, Kelly

2016-01-01

The Advanced Topographic Laser Altimeter System (ATLAS) on the Ice, Cloud, and Land Elevation Satellite (ICESat-2) mission is a six beam, low energy, high repetition rate, 532-nanometer laser transmitter with photon counting detectors. Although designed primarily for detecting height changes in ice caps, sea ice, and vegetation, the polar-orbiting satellite will observe global surface water during its designed three-year life span, including inland waterbodies, coasts, and open oceans. In preparation for the mission, an ICESat-2 prototype, the Multiple Altimeter Beam Experimental Lidar (MABEL), was built and flown on high-altitude aircraft experiments over a range of inland and near-shore targets. The purpose was to test the ATLAS concept and to provide a database for developing an algorithm that detects along track surface water height and light penetration under a range of atmospheric and water conditions. The current analysis examines the data sets of three MABEL transects observed from 20 kilometers above ground of coastal and inland waters conducted in 2012 and 2013. Transects ranged from about 2 to 12 kilometers in length and included the middle Chesapeake Bay, the near-shore Atlantic coast at Virginia Beach, and Lake Mead. Results indicate MABEL's high capability for retrieving surface water height statistics with a mean height precision ofapproximately 5-7 centimeters per 100-meter segment length. Profiles of attenuated subsurface backscatter, characterized using a Signal to Background Ratio written in Log10 base, or LSBR (sub 0), were observed over a range of 1.3 to 9.3 meters, depending on water clarity and atmospheric background. Results indicate that observable penetration depth, although primarily dependent on water properties, was greatest when the solar background rate was low. Near-shore bottom reflectance was detected only at the Lake Mead site down to a maximum of 10 meters under a clear night sky and low turbidity of approximately 1.6 Nephelometric Turbidity Units (NTU). The overall results suggest that the feasibility of retrieving operational surface water height statistics from space-based photon counting systems such as ATLAS is very high for resolutions down to about 100 meters, even in partly cloudy conditions. The capability to observe subsurface backscatterprofiles is achievable but requires much longer transects of several hundreds of meters.

Support of Coastal Fishes by Nearshore and Coastal Wetland Habitats

EPA Science Inventory

Hydrologic linkages among Great Lakes nearshore and coastal wetlands free coastal fish to move among the habitats, which has led to a variety of habitat use patterns. Fine-scale microchemical analyses of yellow perch otoliths have revealed life-history categories that include per...

Spatial Patterns of Subtidal Benthic Invertebrates and Environmental Factors in the Nearshore Gulf of Maine

EPA Science Inventory

The spatial patterns of subtidal benthic invertebrates and physical-chemical variables in the nearshore Gulf of Maine (Acadian Biogeographic Province) were studied to provide information needed to calibrate benthic indices of environmental condition, determine physical-chemical f...

Phytoplankton community composition in nearshore coastal waters of Louisiana

EPA Science Inventory

Phytoplankton community compositions within near-shore coastal and estuarine waters of Louisiana were characterized by relative abundance, biovolume, and taxonomic identification to genus and species when possible. The range of total nitrogen was 0.5 to 1.3 mg L-1 and total phos...

Monitoring landscape influence on nearshore condition

EPA Science Inventory

A major source of stress to the Great Lakes comes from tributary and landscape run-off. The large number of watersheds and the disparate landuse within them create variability in the tributary input along the extent of the nearshore. Identifying the local or regional response t...

Nutrients and the Great Lakes Nearshore, Circa 2002-2007

EPA Science Inventory

Nearshore nutrient impressions were largely limited to observations of local spatial trends from a few site-specific studies and some temporal trends at a set of Canadian water intake locations (later summarized in Nicholls et al. 1999). Lacking a systematic information base fo...

Practical use of video imagery in nearshore oceanographic field studies

USGS Publications Warehouse

Holland, K.T.; Holman, R.A.; Lippmann, T.C.; Stanley, J.; Plant, N.

1997-01-01

An approach was developed for using video imagery to quantify, in terms of both spatial and temporal dimensions, a number of naturally occurring (nearshore) physical processes. The complete method is presented, including the derivation of the geometrical relationships relating image and ground coordinates, principles to be considered when working with video imagery and the two-step strategy for calibration of the camera model. The techniques are founded on the principles of photogrammetry, account for difficulties inherent in the use of video signals, and have been adapted to allow for flexibility of use in field studies. Examples from field experiments indicate that this approach is both accurate and applicable under the conditions typically experienced when sampling in coastal regions. Several applications of the camera model are discussed, including the measurement of nearshore fluid processes, sand bar length scales, foreshore topography, and drifter motions. Although we have applied this method to the measurement of nearshore processes and morphologic features, these same techniques are transferable to studies in other geophysical settings.

Comparison of fishes in nearshore areas of the St. Lawrence River, New York over 35 years

USGS Publications Warehouse

Carlson, Douglas M.; McKenna, James E.

2014-01-01

Fishes of the nearshore waters of the St. Lawrence River provide forage for valuable sport fisheries and are important biological indicators of condition and change. This fish community differs slightly among various reaches of the St. Lawrence River from New York to Quebec (Carlson et al. 2006, Eckert and Hanlon 1977, Kapuscinski 2011, LaViolette et al. 2003, Mandrak et al. 2006, McKenna et al. 2005). Nearshore habitat has been described by McKenna et al. (2012), and others have suggested that there were changes over the last few decades (Clapsadl 1993, Kapuscinski and Farrell 2013). More definitive work needs to be completed on submerged aquatic vegetation habitats. In this paper, changes in the nearshore fish species composition for the New York reach from Cape Vincent to Moses-Saunders Dam are examined through comparison of results from 2009-2010 (McKenna et al. 2012) and 1976 surveys (Eckert and Hanlon 1977).

Status and trends in the Lake Superior fish community, 2015

USGS Publications Warehouse

Vinson, Mark; Evrard, Lori M.; Gorman, Owen T.; Yule, Daniel L.

2016-01-01

In 2015, the Lake Superior fish community was sampled with daytime bottom trawls at 76 nearshore and 33 offshore stations. Spring and summer water temperatures in 2015 were colder than average, but warmer than that observed in 2014. In the nearshore zone, a total of 11,882 individuals from 22 species or morphotypes were collected. Nearshore lakewide mean biomass was 1.8 kg/ha, which was near the lowest biomass on record for this survey since it began in 1978. In the offshore zone, a total 12,433 individuals from 8 species or morphotypes were collected lakewide. Offshore lakewide mean biomass was 5.9 kg/ha. The mean of the four previous years was 7.1 kg/ha. The abundance of age-1 Cisco was 14.3 fish/ha which was similar to that measured in 2009. We collected larval Coregonus in surface trawls at 94 locations and estimated a nearshore lakewide average density of 1,459 fish/ha which was nearly twice that measured in 2014.

The history of dinosaur footprint discoveries in Wyoming with emphasis on the Bighorn Basin

USGS Publications Warehouse

Kvale, Erik P.; Mickelson, Debra L.; Hasiotis, Stephen T; Johnson, Gary D.

2003-01-01

Dinosaur traces are well known from the western United States in the Colorado Plateau region (Utah, Colorado, New Mexico, and Arizona). Utah contains the greatest abundance of known and documented dinosaur footprints and trackways. Far less well known, however, is the occurrence and distribution of dinosaur footprint-bearing horizons in Wyoming. Scientific studies over the past 10 years have shown that three of the four Middle and Upper Jurassic formations in northern Wyoming contain dinosaur footprints. Two of the footprint-bearing horizons are located in geologic intervals that were once thought to have been deposited in offshore to nearshore marine settings and represent rare North American examples of Middle Jurassic (Bajocian and Bathonian) dinosaur remains. Some of these new Wyoming sites can be correlated to known dinosaur footprint-bearing horizons or intervals in Utah. Wyoming has a great potential for additional discoveries of new dinosaur footprint-bearing horizons, and further prospecting and study is warranted and will ultimately lead to a much better understanding of the geographic distribution and behavior of the potential footprint-makers.

Analyzing the Impacts of Land Use Land Change on Near Shore Coastal Habitat

NASA Astrophysics Data System (ADS)

Lehman, R. D.; Ta, E.; Boyle, C.; Alwood, B.

2017-12-01

The natural beauty of the United States Virgin Islands (USVI) has continued to attract visitors and residents, which overtime has increased human development and impact. The resulting land use change increases sediment loads and the flow of pollutants into surrounding nearshore environments such as coral reefs, mangroves, and seagrass beds. Compounded with regional climate-related processes such as rising ocean temperatures and acidification, future land-use change poses a formidable threat to coral reefs and other susceptible marine environments. Without a healthy environment, the USVI economy also becomes endangered because it is mainly supported by tourism and recreation. Using Google Earth Engine, we created a tool to composite yearly Landsat 5 TM, Landsat 8 OLI/TIRS and Sentinel-2 MSI images identify changes from 1985 to present day. Using these land cover change maps we then analyzed trends at a watershed scale using hydrological data. We found there is a spatial relationship between development intensity and the health of coral reefs. Our work supports the existing knowledge of the link between land use and coastal ecosystem health.

Development of a Hydrodynamic Model of Puget Sound and Northwest Straits

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

Yang, Zhaoqing; Khangaonkar, Tarang P.

2007-12-10

The hydrodynamic model used in this study is the Finite Volume Coastal Ocean Model (FVCOM) developed by the University of Massachusetts at Dartmouth. The unstructured grid and finite volume framework, as well as the capability of wetting/drying simulation and baroclinic simulation, makes FVCOM a good fit to the modeling needs for nearshore restoration in Puget Sound. The model domain covers the entire Puget Sound, Strait of Juan de Fuca, San Juan Passages, and Georgia Strait at the United States-Canada Border. The model is driven by tide, freshwater discharge, and surface wind. Preliminary model validation was conducted for tides at variousmore » locations in the straits and Puget Sound using National Oceanic and Atmospheric Administration (NOAA) tide data. The hydrodynamic model was successfully linked to the NOAA oil spill model General NOAA Operational Modeling Environment model (GNOME) to predict particle trajectories at various locations in Puget Sound. Model results demonstrated that the Puget Sound GNOME model is a useful tool to obtain first-hand information for emergency response such as oil spill and fish migration pathways.« less

Dissolved organic matter properties in arctic coastal waters are strongly influenced by degrading permafrost coasts and by local meteorology.

NASA Astrophysics Data System (ADS)

Fritz, M.; Tanski, G.; Goncalves-Araujo, R.; Heim, B.; Koch, B.; Lantuit, H.

2016-12-01

Organic carbon and nutrients are increasingly mobilized from permafrost coasts due to accelerated coastal erosion in response to Arctic warming. The nearshore zone plays a crucial role in Arctic biogeochemical cycling, as here the released material is destined to be (1) mineralized into greenhouse gases, (2) incorporated into marine primary production, (3) buried in nearshore sediments or (4) transported offshore. We present dissolved organic matter (DOM) quantities in surface water in the nearshore zone of the southern Beaufort Sea from three consecutive summer seasons under different meteorological conditions. Colored and fluorescent dissolved organic matter (cDOM, fDOM) properties are used to differentiate the terrestrial from the marine DOM component. Dissolved organic carbon (DOC) concentrations in the nearshore zone of the southern Beaufort Sea vary between about 1.5 and 5 mg C L-1. In low salinity conditions between 8 and 15, high DOC concentrations of 3.5 to 5 mg C L-1prevail. Storm events can lead to strongly decreased DOC concentration and increasing salinity (14 to 28) in surface water, probably due to upwelling. In windy and wavy conditions throughout the season, the water column is well-mixed and DOC-poor because saline waters are transported from the offshore to the nearshore. We recognized a significant negative correlation between DOC and salinity, independent from varying meteorological conditions. This suggests conservative mixing between DOC derived from permafrost coasts and marine primary production. Stable stratification in the nearshore zone and calm weather conditions will increase the influence of terrestrial-derived DOM and the potential turnover time for biogeochemical cycling in coastal ecosystems. The strength of the terrestrial influence can be estimated by salinity and stable water isotope measures as they directly correlate with DOC concentrations; the lower the salinity the stronger the terrestrial influence. We conclude that the terrestrial footprint of coastal erosion on DOM concentrations in the nearshore zone is significant and may increase with future climate warming. Meteorological conditions play a major role for the strength of the terrestrial DOM signal, which can vary on short timescales.

Perfluorinated compounds in fish from U.S. urban rivers and the Great Lakes.

PubMed

Stahl, Leanne L; Snyder, Blaine D; Olsen, Anthony R; Kincaid, Thomas M; Wathen, John B; McCarty, Harry B

2014-11-15

Perfluorinated compounds (PFCs) have recently received scientific and regulatory attention due to their broad environmental distribution, persistence, bioaccumulative potential, and toxicity. Studies suggest that fish consumption may be a source of human exposure to perfluorooctane sulfonate (PFOS) or long-chain perfluorocarboxylic acids. Most PFC fish tissue literature focuses on marine fish and waters outside of the United States (U.S.). To broaden assessments in U.S. fish, a characterization of PFCs in freshwater fish was initiated on a national scale using an unequal probability design during the U.S. Environmental Protection Agency's (EPA's) 2008-2009 National Rivers and Streams Assessment (NRSA) and the Great Lakes Human Health Fish Tissue Study component of the 2010 EPA National Coastal Condition Assessment (NCCA/GL). Fish were collected from randomly selected locations--164 urban river sites and 157 nearshore Great Lake sites. The probability design allowed extrapolation to the sampled population of 17,059 km in urban rivers and a nearshore area of 11,091 km(2) in the Great Lakes. Fillets were analyzed for 13 PFCs using high-performance liquid chromatography tandem mass spectrometry. Results showed that PFOS dominated in frequency of occurrence, followed by three other longer-chain PFCs (perfluorodecanoic acid, perfluoroundecanoic acid, and perfluorododecanoic acid). Maximum PFOS concentrations were 127 and 80 ng/g in urban river samples and Great Lakes samples, respectively. The range of NRSA PFOS detections was similar to literature accounts from targeted riverine fish sampling. NCCA/GL PFOS levels were lower than those reported by other Great Lakes researchers, but generally higher than values in targeted inland lake studies. The probability design allowed development of cumulative distribution functions (CDFs) to quantify PFOS concentrations versus the sampled population, and the application of fish consumption advisory guidance to the CDFs resulted in an estimation of the proportion of urban rivers and the Great Lakes that exceed human health protection thresholds. Copyright © 2014. Published by Elsevier B.V.

Optical Polarization in the Nearshore

NASA Astrophysics Data System (ADS)

Holman, R.

2008-12-01

A recent addition to the suite of optical remote sensing methods that have been used to study nearshore processes is the use of imaging polarimetric cameras. Both the degree of polarization and the azimuth of polarized light contain information about the imaged surfaces from which light has been reflected or scattered. In 2007, a polarimetric Argus camera was installed atop the tower at Duck, NC. This talk will examine the various polarization signatures that can be exploited, including the potential for measuring the sea surface slope spectrum of nearshore surf zone waves, the slope of the foreshore beach, water content of foreshore sediments and bubble signatures of dissipating waves.

California nearshore processes - ERTS 1. [coastal currents and sediments

NASA Technical Reports Server (NTRS)

Steller, D. D.; Pirie, D. M.

1974-01-01

The detectability of many nearshore processes from ERTS is made possible due to the suspended sediment present in the coastal waters. From viewing and analyzing the California coastal imagery collected during the last year and a half, the overall current patterns and their changes have become evident. It is now possible to map monthly and seasonal changes that occur throughout the year. The original objectives of detecting currents, sediment transport, estuaries and river discharge have now been expanded to include the use of ERTS information in operational problems of the U.S. Army Corps of Engineers. This incorporates the detected nearshore features into planning and organizing shore protection facilities.

What models can teach us about watershed-nearshore relationships that observational studies cannot

EPA Science Inventory

The nearshore waters of the Laurentian Great Lakes are a valuable resource for drinking water, recreation, fishing, wildlife and industrial usage. However, environmental concerns such as eutrophication and the colonization of invasive species have resulted in the call for an over...

Ecology of Lake Superior: Linking Landscape to Nearshore Condition

EPA Science Inventory

High spatial variation is well known to exist in water quality parameters of the Great Lakes nearshore, however strong patterns for extended reaches are also observed and found to be robust across a seasonal time frame. Less is known about robustness of inter-annual variation wi...

Analysis of near-shore sea surface temperatures in the Northern Pacific

EPA Science Inventory

Recent studies report a warming trend in Pacific Ocean temperatures over the last 50 years. However, much less is known about temperature change in the near-coastal environment, which is particularly sensitive to climatic change. In near-shore regions in situ sea surface temper...

Nearshore marine benthic invertebrates moving north along the U.S. Atlantic coast

EPA Science Inventory

Numerous species have shifted their ranges north in response to global warming. We examined 21 years (1990-2010) of marine benthic invertebrate data from the National Coastal Assessment’s monitoring of nearshore waters along the US Atlantic coast. Data came from three bioge...

Lake Michigan Green Bay: Nearshore Variability

EPA Science Inventory

We conducted a high-resolution survey in the nearshore of Lake Michigan’s Green Bay at a 15 meter contour using towed electronic instrumentation. The 365 km survey was conducted Aug 18-21, 2010. We also conducted four cross-contour tows. Along the survey tracks we sampled fixe...

Eutrophication monitoring for Lake Superior’s Chequamegon Bay before and after large summer storms

EPA Science Inventory

A priority for the Lake Superior CSMI was to identify susceptible nearshore eutrophication areas. We developed an integrated sampling design to collect baseline data for Lake Superior’s Chequamegon Bay to understand how nearshore physical processes and tributary loading rel...

Lake Superior: Nearshore Variability and a Landscape Driver Concept

EPA Science Inventory

High spatial variation is well known to exist in water quality parameters of the Great Lakes nearshore, however strong patterns for extended reaches are also observed and found to be robust across a seasonal time frame. Less is known about robustness of inter-annual variation wi...

FINDING AND READING ECOLOGICAL SIGNALS IN THE NEARSHORE OF THE GREAT LAKES

EPA Science Inventory

Adjunct UMD faculty make annual presentations on research interest to IBS graduate students and faculty. Talks engage students in research and application to environmental problems. This presentation discusses the ecology of the nearshore areas of the Great Lakes, and ways to fi...

Shoreline migration and beach-nearshore sand balance over the last 200 years in Haifa Bay (SE Mediterranean)

NASA Astrophysics Data System (ADS)

Zviely, Dov; Kit, Eliezer; Rosen, Baruch; Galili, Ehud; Klein, Micha

2009-04-01

Several researchers have investigated morphological changes on the south-eastern Mediterranean coast during the late Holocene. However, very few of these studies include quantitative data covering the last 200 years. In this study, topographical maps, nautical charts and aerial photographs are used to estimate the shoreline migrations and beach-nearshore sand balance over the last 200 years in Haifa Bay, Israel, the northernmost final depositional sink of the Nile littoral cell. The findings reflect two main periods. During the first period, between 1799 and 1928, human intervention along the bay's coast was negligible, a significant coastal expansion of ˜50 to 150 m (averages of 0.4-1.2 m/year) was measured, and sand accumulation was estimated at ˜70,000 m3 annually in the beach-nearshore area. A dramatic change in the sedimentological pattern was observed during the second period, between 1928 and 2006, following the completion of Haifa Port's main breakwater (1929-1933). During this period, most of the bay's coast was in a steady state, with seasonal fluctuations of less than about ±20 m, and slight erosion of ˜7,000 m3 annually. These findings are consistent with previous studies which conclude that from approximately 4,000 years ago until the construction of Haifa Port, sea level remained relatively stable, and a continuous accumulation of Nile-derived sand dried up the Zevulun Plain and shifted the Haifa Bay shoreline westwards to its present location. This long-term trend ceased after completion of the Haifa Port main breakwater.

Observations of nearshore groundwater discharge: Kahekili Beach Park submarine springs, Maui, Hawaii

USGS Publications Warehouse

Swarzenski, Peter W.; Dulai, H.; Kroeger, K.D.; Smith, C.G.; Dimova, N.; Storlazzi, C. D.; Prouty, N.G.; Gingerich, S.B.; Glenn, C. R.

2016-01-01

Study regionThe study region encompasses the nearshore, coastal waters off west Maui, Hawaii. Here abundant groundwater—that carries with it a strong land-based fingerprint—discharges into the coastal waters and over a coral reef.Study focusCoastal groundwater discharge is a ubiquitous hydrologic feature that has been shown to impact nearshore ecosystems and material budgets. A unique combined geochemical tracer and oceanographic time-series study addressed rates and oceanic forcings of submarine groundwater discharge at a submarine spring site off west Maui, Hawaii.New hydrological insights for the regionEstimates of submarine groundwater discharge were derived for a primary vent site and surrounding coastal waters off west Maui, Hawaii using an excess 222Rn (t1/2 = 3.8 d) mass balance model. Such estimates were complemented with a novel thoron (220Rn,t1/2 = 56 s) groundwater discharge tracer application, as well as oceanographic time series and thermal infrared imagery analyses. In combination, this suite of techniques provides new insight into the connectivity of the coastal aquifer with the near-shore ocean and examines the physical drivers of submarine groundwater discharge. Lastly, submarine groundwater discharge derived constituent concentrations were tabulated and compared to surrounding seawater concentrations. Such work has implications for the management of coastal aquifers and downstream nearshore ecosystems that respond to sustained constituent loadings via this submarine route.

Depositional response to seagrass mortality along a low-energy, barrier-island coast: west-central Florida

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

Evans, M.W.; Hine, A.C.; David, R.A.

1985-01-01

Analysis of aerial photographs and surficial sediment samples from the northern islands of the west-central barrier system of Florida indicates that: (1) seagrass beds in the nearshore zone have controlled onshore/longshore sand transport, and (2) resulting sedimentary accumulations within nearshore seagrass beds make differentiation of nearshore and backbarrier facies difficult. Between 1957 and 1973, an extensive seagrass community occupying the nearshore zone off Anclote Key disappeared, thus allowing the sudden and rapid onshore and longshore transport of sand. The 1000 year old barrier island lengthened 30% by recurved spit growth in this very short period of time. Although there aremore » not direct observations, four possible causes of seagrass mortality have been postulated, and of these overgrazing as a result of the accelerated population growth of sea urchins (Lytechinus variegatus) seems to be the most likely cause. Because of the ability of seagrasses to trap fine-grained sediments, contribute organic matter, and provide for low-energy, sheltered, molluscan biocoenosis, there is little depositional difference between these nearshore and backbarrier/lagoonal facies. This work indicates that the development and destruction of benthic floral communities should be considered as a process that generates or accentuates episodicity/cyclicity in the sedimentary record. Additionally, such changes in these communities should be expected to present a blurred distinction between certain types of coastal sedimentary facies.« less

Evidence of extensive reef development and high coral cover in nearshore environments: implications for understanding coral adaptation in turbid settings

PubMed Central

Morgan, Kyle M.; Perry, Chris T.; Smithers, Scott G.; Johnson, Jamie A.; Daniell, James J.

2016-01-01

Mean coral cover has reportedly declined by over 15% during the last 30 years across the central Great Barrier Reef (GBR). Here, we present new data that documents widespread reef development within the more poorly studied turbid nearshore areas (<10 m depth), and show that coral cover on these reefs averages 38% (twice that reported on mid- and outer-shelf reefs). Of the surveyed seafloor area, 11% had distinct reef or coral community cover. Although the survey area represents a small subset of the nearshore zone (15.5 km2), this reef density is comparable to that measured across the wider GBR shelf (9%). We also show that cross-shelf coral cover declines with distance from the coast (R2 = 0.596). Identified coral taxa (21 genera) exhibited clear depth-stratification, corresponding closely to light attenuation and seafloor topography, with reefal development restricted to submarine antecedent bedforms. Data from this first assessment of nearshore reef occurrence and ecology measured across meaningful spatial scales suggests that these coral communities may exhibit an unexpected capacity to tolerate documented declines in water quality. Indeed, these shallow-water nearshore reefs may share many characteristics with their deep-water (>30 m) mesophotic equivalents and may have similar potential as refugia from large-scale disturbances. PMID:27432782

The effect of ship scrapping industry and its associated wastes on the biomass production and biodiversity of biota in in situ condition at Alang.

PubMed

Tewari, A; Joshi, H V; Trivedi, R H; Sravankumar, V G; Raghunathan, C; Khambhaty, Y; Kotiwar, O S; Mandal, S K

2001-06-01

The main pollutants for the ship scrapping industry and its associated wastes at Alang are heavy metals, petroleum hydrocarbon and bacterial contaminations. The concentration of iron, manganese, cobalt, copper, zinc, lead, cadmium, nickel and mercury were 25 to 15,500% more at nearshore station of Alang as compared to control site at Piram. The concentration of heavy metals in the nearshore station of Alang was always higher than its concentration at 10 km away. The concentration of petroleum hydrocarbon was 16,973 and 53,900% more at the nearshore and 10 km away respectively at Alang as compared to controls. The concentration of chlorophyll-a and phaeophytin were in non-detectable range (< 0.2 and < 0.1 mg m3) or much lower concentration at both the stations of Alang as compared to controls. The total viable count, total coliform, Escherichia coli, Vibrio cholerae, Vibrio parahaemolyticus and other Vibrio, Streptococcus faecalis, Shigella, Salmonella, Proteus, and Klebsiella were always higher (17%-605%) at the nearshore station of Alang as compared to control. Similar trend was observed at 10 km away from Alang. Bacteria in sediment also showed the same pattern of variation. Phytoplankton counts at the nearshore station and 10 km away from Alang were only slightly raised. In contrast to phytoplankton, the zooplankton showed considerable reduction of growth (-10 to -66%) at Alang.

Evidence of extensive reef development and high coral cover in nearshore environments: implications for understanding coral adaptation in turbid settings.

PubMed

Morgan, Kyle M; Perry, Chris T; Smithers, Scott G; Johnson, Jamie A; Daniell, James J

2016-07-19

Mean coral cover has reportedly declined by over 15% during the last 30 years across the central Great Barrier Reef (GBR). Here, we present new data that documents widespread reef development within the more poorly studied turbid nearshore areas (<10 m depth), and show that coral cover on these reefs averages 38% (twice that reported on mid- and outer-shelf reefs). Of the surveyed seafloor area, 11% had distinct reef or coral community cover. Although the survey area represents a small subset of the nearshore zone (15.5 km(2)), this reef density is comparable to that measured across the wider GBR shelf (9%). We also show that cross-shelf coral cover declines with distance from the coast (R(2) = 0.596). Identified coral taxa (21 genera) exhibited clear depth-stratification, corresponding closely to light attenuation and seafloor topography, with reefal development restricted to submarine antecedent bedforms. Data from this first assessment of nearshore reef occurrence and ecology measured across meaningful spatial scales suggests that these coral communities may exhibit an unexpected capacity to tolerate documented declines in water quality. Indeed, these shallow-water nearshore reefs may share many characteristics with their deep-water (>30 m) mesophotic equivalents and may have similar potential as refugia from large-scale disturbances.

California State Waters Map Series: offshore of Pacifica, California

USGS Publications Warehouse

Edwards, Brian D.; Phillips, Eleyne L.; Dartnell, Peter; Greene, H. Gary; Bretz, Carrie K.; Kvitek, Rikk G.; Hartwell, Stephen R.; Johnson, Samuel Y.; Cochrane, Guy R.; Dieter, Bryan E.; Sliter, Ray W.; Ross, Stephanie L.; Golden, Nadine E.; Watt, Janet Tilden; Chinn, John L.; Erdey, Mercedes D.; Krigsman, Lisa M.; Manson, Michael W.; Endris, Charles A.; Cochran, Susan A.; Edwards, Brian D.

2015-01-01

The continental shelf in the map area is about 40 km wide, with water depths at the shelf break that range from about 80 to 120 m. Within California’s State Waters, the midshelf to inner shelf areas are characterized by a relatively flat, shallow (water depths of as much as 44 m) seafloor that dips gently (about 0.2° to 0.3°) westward. The seafloor is composed primarily of unconsolidated Holocene sediment (marine deposits), as well as some nearshore bedrock outcrops that consist primarily of rocks of the Tertiary Purisima Formation and also Cretaceous plutonic rocks (granite or granodiorite).

VARIABILITY, PATTERN, AND SENSITIVITY OF ECOLOGICAL INDICAORS FOR NEARSHORE REGIONS OF THE GREAT LAKES

EPA Science Inventory

Associated with the Great Lakes Environmental Indicators (GLEI) project of the EaGLe program, we are evaluating a suite of indicators of ecological condition for the nearshore region of U.S. shorelines of the Great Lakes. The evaluation includes sampling conducted at limited fix...

Reconstructing fish movements between coastal wetland and nearshore habitats of the Great Lakes

EPA Science Inventory

The use of resources from multiple habitats has been shown to be important to the production of aquatic consumers. To quantify the support of Great Lakes coastal wetland (WL) and nearshore (NS) habitats to yellow perch, we used otolith microchemistry to trace movements between th...

What happens to near-shore habitat when lake and reservoir water levels decline?

EPA Science Inventory

Water management and drought can lead to increased fluctuation and declines in lake and reservoir water levels. These changes can affect near-shore physical habitat and the biotic assemblages that depend upon it. Structural complexity at the land-water interface of lakes promote...

50 CFR 697.20 - Size, harvesting and landing requirements.

Code of Federal Regulations, 2011 CFR

2011-10-01

... length. (1) The minimum carapace length for all American lobsters harvested in or from the EEZ Nearshore... length for all American lobsters landed, harvested, or possessed by vessels issued a Federal limited access American lobster permit fishing in or electing to fish in the Nearshore Management Area 1 or the...

50 CFR 697.20 - Size, harvesting and landing requirements.

Code of Federal Regulations, 2010 CFR

2010-10-01

... length. (1) The minimum carapace length for all American lobsters harvested in or from the EEZ Nearshore... length for all American lobsters landed, harvested, or possessed by vessels issued a Federal limited access American lobster permit fishing in or electing to fish in the Nearshore Management Area 1 or the...

Preliminary Results from a Benthic Video Survey of the Lake Huron Nearshore

EPA Science Inventory

We used down looking and oblique videography to examine benthic conditions in the Nearshore of Lake Huron in August 2017. Video was collected at multiple stations clustered at 8 general locations in Lake Huron: off the Thessalon River and the Spanish River in the North Channel; o...

Evaluating a Lake Tahoe nearshore assessment strategy: A circumnavigation survey, August 2011

EPA Science Inventory

We had the opportunity to apply a high-resolution nearshore sampling strategy, developed in the US/Canadian Laurentian Great Lakes, to Lake Tahoe. The strategy uses towed in situ sensors (physico-chemistry and biology) oscillated from near surface to near bottom while a vessel i...

Lake Superior: Nearshore Variability and a Landscape Driver Concept (journal article)

EPA Science Inventory

Spatial variation is well known to exist in water quality parameters of the Great Lakes nearshore, however strong patterns for extended reaches also have been observed and found to be robust across seasonal time frames. Less is known about robustness of inter-annual variation wi...

78 FR 35217 - Atlantic Coastal Fisheries Cooperative Management Act Provisions; American Lobster Fishery

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-12

.... 080219213-3470-01] RIN 0648-AT31 Atlantic Coastal Fisheries Cooperative Management Act Provisions; American... lobster trap fishery in Lobster Conservation Management Area 2 (Federal nearshore waters in Southern New England; Area 2), and in the Outer Cape Cod Lobster Conservation Management Area (Federal nearshore waters...

Using National Coastal Condition Assessment Underwater Video to Investigate Nearshore Substrate Type

EPA Science Inventory

A comprehensive method for describing bottom types in Great Lakes nearshore regions (<30 m deep and <5 km from shore) would enhance our ability to target monitoring efforts. Dredges are ineffective at sampling hard bottoms (bedrock/boulder/cobble) and other habitat features. We a...

A Curvilinear Version of a Quasi-3D Nearshore Circulation Model

DTIC Science & Technology

2002-01-01

Warsi, 1998), in comparison to the Cartesian component method (see, for example, Häuser et al., 1985, 1986; Raghunath et al., 1987; Borthwick and Barber...1999. Three-dimensional dispersion of momentum in wave-induced nearshore currents. Eur. J. Mech., 83–101. Raghunath , R., Sengupta, S., Häuser, J., 1987

Principal sources and dispersal patterns of suspended particulate matter in nearshore surface waters of the northeast Pacific Ocean and the Hawaiian Islands

NASA Technical Reports Server (NTRS)

Carlson, P. R. (Principal Investigator); Conomos, T. J.; Janda, R. J.; Peterson, D. H.

1973-01-01

The author has identified the following significant results. ERTS-1 multispectral scanner imagery of the nearshore surface waters of the Northeast Pacific Ocean is proving to be a useful tool for determining source and dispersal of suspended particulate matter. The principal sources of the turbid water, seen best on the green and red bands, are river and stream effluents and actively eroding coastlines; secondary sources are waste effluents and production of planktonic organisms, but these may sometimes be masked by the very turbid plumes of suspended sediment being discharged into the nearshore zone during times of high river discharge. The configuration and distribution of the plumes of turbid water also can be used to infer near-surface current directions. Comparison of imagery of the nearshore water off the northern California coast from October 1972 and January 1973 shows a reversal of the near-surface currents, from predominantly south-setting in the fall (California Current) to north-setting in the winter (Davidson Current).

Factors associated with the deposition of Cladophora on Lake Michigan beaches in 2012

USGS Publications Warehouse

Riley, Stephen C.; Tucker, Taaja R.; Adams, Jean V.; Fogarty, Lisa R.; Lafrancois, Brenda Moraska

2015-01-01

Deposition of the macroalgae Cladophora spp. was monitored on 18 beaches around Lake Michigan during 2012 at a high temporal frequency. We observed a high degree of spatial variability in Cladophora deposition among beaches on Lake Michigan, even within local regions, with no clear regional pattern in the intensity of Cladophora deposition. A strong seasonal pattern in Cladophora deposition was observed, with the heaviest deposition occurring during mid-summer. Several beaches exhibited high temporal variability in Cladophora deposition over short time scales, suggesting that drifting algal mats may be extremely dynamic in nearshore environments of the Great Lakes. Cladophora deposition on Lake Michigan beaches was primarily related to the presence of nearshore structures, local population density, and nearshore bathymetry. There was relatively little evidence that waves, winds, or currents were associated with Cladophora deposition on beaches, but this may be due to the relatively poor resolution of existing nearshore hydrodynamic data. Developing a predictive understanding of beach-cast Cladophora dynamics in Great Lakes environments may require both intensive Cladophora monitoring and fine-scale local hydrodynamic modeling efforts.

Status and trends in the Lake Superior fish community, 2016

USGS Publications Warehouse

Vinson, Mark; Evrard, Lori M.; Gorman, Owen T.; Yule, Daniel

2017-01-01

In 2016, the Lake Superior fish community was sampled with daytime bottom trawls at 76 nearshore and 35 offshore stations. Spring and summer water temperatures in 2016 were warmer than average and considerably warmer than observed in 2014 and 2015. In the nearshore zone, a total of 17,449 individuals from 20 species or morphotypes were collected. Nearshore lakewide mean biomass was 2.2 kg/ha, which was near the lowest biomass on record for this survey since it began in 1978. In the offshore zone, a total 8,487 individuals from 16 species or morphotypes were collected lakewide. Offshore lakewide mean biomass was 4.5 kg/ha, which was the lowest biomass recorded since the offshore survey began in 2011. The density of age-1 Cisco was 5.0 fish/ha, which was 35% of that measured in 2015. Larval Coregonus were collected in surface trawls at 144 locations lakewide from May to July. The average nearshore lakewide larval Coregonus density estimate was 1,630 fish/ha, which was similar to that estimated in 2015.

How Does Variability in Aragonite Saturation Proxies Impact Our Estimates of the Intensity and Duration of Exposure to Aragonite Corrosive Conditions in a Coastal Upwelling System?

NASA Astrophysics Data System (ADS)

Abell, J. T.; Jacobsen, J.; Bjorkstedt, E.

2016-02-01

Determining aragonite saturation state (Ω) in seawater requires measurement of two parameters of the carbonate system: most commonly dissolved inorganic carbon (DIC) and total alkalinity (TA). The routine measurement of DIC and TA is not always possible on frequently repeated hydrographic lines or at moored-time series that collect hydrographic data at short time intervals. In such cases a proxy can be developed that relates the saturation state as derived from one time or infrequent DIC and TA measurements (Ωmeas) to more frequently measured parameters such as dissolved oxygen (DO) and temperature (Temp). These proxies are generally based on best-fit parameterizations that utilize references values of DO and Temp and adjust linear coefficients until the error between the proxy-derived saturation state (Ωproxy) and Ωmeas is minimized. Proxies have been used to infer Ω from moored hydrographic sensors and gliders which routinely collect DO and Temp data but do not include carbonate parameter measurements. Proxies can also calculate Ω in regional oceanographic models which do not explicitly include carbonate parameters. Here we examine the variability and accuracy of Ωproxy along a near-shore hydrographic line and a moored-time series stations at Trinidad Head, CA. The saturation state is determined using proxies from different coastal regions of the California Current Large Marine Ecosystem and from different years of sampling along the hydrographic line. We then calculate the variability and error associated with the use of different proxy coefficients, the sensitivity to reference values and the inclusion of additional variables. We demonstrate how this variability affects estimates of the intensity and duration of exposure to aragonite corrosive conditions on the near-shore shelf and in the water column.

Exxon Valdez Oil Spill Restoration Project final report: Monitoring for evaluation of recovery and restoration of injured nearshore resources

USGS Publications Warehouse

Ballachey, Brenda E.; Bodkin, James L.; Kloecker, Kimberly A.; Dean, Tom; Colettie, Heather A

2015-01-01

In 2012, we completed three consecutive years of full field sampling in WPWS for EVOS Restoration Project 10100750. Nearshore monitoring was conducted in collaboration with the NPS SWAN I&M program and, beginning in 2012, as part of the EVOSTC GWA program. Data collection was done in accordance with standard operating procedures set forth to monitor marine water chemistry and quality, marine intertidal invertebrates, kelps and seagrasses, marine birds, black oystercatchers, and sea otters. Summer sampling in 2012 represented the fourth year of sampling in WPWS (an initial year of sampling was done in WPWS in 2007; EVOS Restoration Project 070750). Based on our monitoring of nearshore species in WPWS, and comparisons of data from WPWS and other areas within the Gulf of Alaska, we have no evidence of continued injury to biological resources at the spatial scales we are monitoring. A key finding is that recovery of the sea otter population is no longer constrained by exposure to lingering oil; this is consistent with related EVOSTC studies on harlequin ducks (Restoration Project 12120114-Q). We anticipate continued annual nearshore monitoring in WPWS and at KATM and KEFJ under GWA, with data summaries and analyses including all three areas to provide a larger spatial and temporal context to the understanding of processes and patterns in nearshore ecosystems of the GOA which were impacted by the EVOS of 1989.

Pressure-gradient-driven nearshore circulation on a beach influenced by a large inlet-tidal shoal system

USGS Publications Warehouse

Shi, F.; Hanes, D.M.; Kirby, J.T.; Erikson, L.; Barnard, P.; Eshleman, J.

2011-01-01

The nearshore circulation induced by a focused pattern of surface gravity waves is studied at a beach adjacent to a major inlet with a large ebb tidal shoal. Using a coupled wave and wave-averaged nearshore circulation model, it is found that the nearshore circulation is significantly affected by the heterogeneous wave patterns caused by wave refraction over the ebb tidal shoal. The model is used to predict waves and currents during field experiments conducted near the mouth of San Francisco Bay and nearby Ocean Beach. The field measurements indicate strong spatial variations in current magnitude and direction and in wave height and direction along Ocean Beach and across the ebb tidal shoal. Numerical simulations suggest that wave refraction over the ebb tidal shoal causes wave focusing toward a narrow region at Ocean Beach. Due to the resulting spatial variation in nearshore wave height, wave-induced setup exhibits a strong alongshore nonuniformity, resulting in a dramatic change in the pressure field compared to a simulation with only tidal forcing. The analysis of momentum balances inside the surf zone shows that, under wave conditions with intensive wave focusing, the alongshore pressure gradient associated with alongshore nonuniform wave setup can be a dominant force driving circulation, inducing heterogeneous alongshore currents. Pressure-gradient- forced alongshore currents can exhibit flow reversals and flow convergence or divergence, in contrast to the uniform alongshore currents typically caused by tides or homogeneous waves.

Variations of Morphologic Changes induced by Tropical Storm Debby along Three Barrier Island, West-Central Florida, USA

NASA Astrophysics Data System (ADS)

Wang, P.; Roberts, T.

2012-12-01

Tropical Storm Debby generated sustained high waves and elevated water levels for nearly three days from June 24th to 26th, 2012, inducing substantial changes in beach and nearshore morphology. In addition, the storm winds and high waves approached the coast from a highly oblique angle from the south, driving substantial northward longshore sand transport, opposite to the regional net annual southward transport. A total of 145 beach and nearshore profiles along 3 adjacent barrier islands were surveyed 2 weeks before and one week after the storm impact. Overall, dune, beach, intertidal, and immediate subtidal areas suffered erosion, while deposition was measured over the nearshore bar. Beach recovery in the form of ridge and runnel development occurred as the storm energy subsided. Substantial longshore variations of storm-induced beach changes were measured, including both severe dune/beach/berm erosion and storm berm accretion, and both onshore and offshore migration of nearshore bar. Factors controlling these longshore variations include: 1) the oblique approaching of the storm forcing, 2) pre-storm beach morphology and chronic erosional or accretional trends, 3) sediment supply, and 4) tidal inlet and beach interactions. Wide spreading dune scarping occurred along the 30-km studied coast. Based on the pre- and post-storm survey data, a balanced sediment budget is obtained accounting for sand volume loss from dune, beach, intertidal, and subtidal zones, and sand gains over the nearshore bar and along the northern sections of the beach.

Modeling nearshore-offshore exchange in Lake Superior

PubMed Central

Tokos, Kathy S.; Matsumoto, Katsumi

2018-01-01

Lake Superior′s ecosystem includes distinct nearshore and offshore food webs linked by hydrodynamic processes that transport water and tracers along and across shore. The scales over which these processes occur and their sensitivity to increasing summer surface temperatures are not well understood. This study investigated horizontal mixing between nearshore and offshore areas of Lake Superior over the 10-year period from 2003 to 2012 using a realistically forced three-dimensional numerical model and virtual tracers. An age tracer was used to characterize the time scales of horizontal mixing between nearshore areas of the lake where water depth is less than 100 m and deeper areas. The age of water in nearshore areas increased and decreased in an annual cycle corresponding to the lake′s dimictic cycle of vertical mixing and stratification. Interannual variability of mixing in the isothermal period was significantly correlated to average springtime wind speed, whereas variability during the stratified season was correlated to the average summer surface temperature. Dispersal of a passive tracer released from nine locations around the model lake’s perimeter was more extensive in late summer when stratification was established lakewide than in early summer. The distribution of eddies resolved in the model reflected differences between the early and late summer dispersal patterns. In the eastern part of the lake dispersal was primarily alongshore, reflecting counterclockwise coastal circulation. In the western part of the lake, cross-shore mixing was enhanced by cross-basin currents. PMID:29447286

Formation, Fate, and Impacts of Microscopic and Macroscopic Oil-Sediment Residues in Nearshore Marine Environments: A Critical Review

NASA Astrophysics Data System (ADS)

Gustitus, Sarah A.; Clement, T. Prabhakar

2017-12-01

Crude oil that is spilled in marine environments often interacts with suspended sediments to form residues that can impact the recovery of the affected nearshore ecosystems. When spilled oil and sediment interact, they can form either small microscopic aggregates, commonly referred to as oil-particle aggregates, or large macroscopic agglomerates, referred to as sediment-oil agglomerates or sediment-oil mats. Although these different sized oil-sediment residues have similar compositions, they are formed under different conditions and have different fates in nearshore environments; the goal of this review is to synthesize our current understanding of these two types of residues. We believe that researchers who focus solely on studying either microscopic aggregates or macroscopic agglomerates could benefit from understanding the research findings available in the other field. In this study, we compare and contrast various processes that control the formation, fate, and impacts of these two types of residues in nearshore environments and point out some of the knowledge gaps in this field. Additionally, these residues have been referred to by many names in the past, leading to confusion and misconceptions at times. In this effort, we recommend a uniform nomenclature to distinguish them based on their physical size. Our overall aim is to bridge the gap between microscopic and macroscopic oil-sediment residue literature to foster a robust exchange of ideas, which we believe can lead to the development of efficient strategies for managing oil spills that affect nearshore environments.

Potential Regional Sediment Management (RSM) Projects in the Haleiwa Region, Oahu, Hawaii

DTIC Science & Technology

2014-05-01

relic stream channels on wave -induced flow patterns. Wave breaking and energy dissipation over the reefs result in return currents (from nearshore to...long), (c) a stub breakwater (80 ft long), and (d) a wave absorber (140 ft long). The non-federal sponsor for the harbor is the State of Hawaii...Coastal Inlets Research Program (CIRP) Coastal Modeling System (CMS) numerical models CMS- Wave and CMS- Flow (Sanchez et al. 2011) were implemented to

Species Profiles. Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Pacific Northwest). Pacific Herring

DTIC Science & Technology

1989-12-01

concluded that the or processing capacity usually limited catches growth rate of juvenile Pacific herring was (Hourston 1980). From about a decade after...and Brett 1988; Hay et al. 1988). processing capacity, most State or Provincial governments now manage these nearshore Herring for human consumption...item (Hart 1973). As the small larvae (mean notochord length, NL, = herring mature, copepods may be superseded by 10.3 mm). Assimilation efficiency

Variability of the carbonate chemistry in a shallow, seagrass-dominated ecosystem: implications for ocean acidification experiments

USGS Publications Warehouse

Challener, Roberta; Robbins, Lisa L.; Mcclintock, James B.

2016-01-01

Open ocean observations have shown that increasing levels of anthropogenically derived atmospheric CO2 are causing acidification of the world's oceans. Yet little is known about coastal acidification and studies are just beginning to characterise the carbonate chemistry of shallow, nearshore zones where many ecologically and economically important organisms occur. We characterised the carbonate chemistry of seawater within an area dominated by seagrass beds (Saint Joseph Bay, Florida) to determine the extent of variation in pH and pCO2 over monthly and daily timescales. Distinct diel and seasonal fluctuations were observed at daily and monthly timescales respectively, indicating the influence of photosynthetic and respiratory processes on the local carbonate chemistry. Over the course of a year, the range in monthly values of pH (7.36-8.28), aragonite saturation state (0.65-5.63), and calculated pCO2 (195-2537 μatm) were significant. When sampled on a daily basis the range in pH (7.70-8.06), aragonite saturation state (1.86-3.85), and calculated pCO2 (379-1019 μatm) also exhibited significant range and indicated variation between timescales. The results of this study have significant implications for the design of ocean acidification experiments where nearshore species are utilised and indicate that coastal species are experiencing far greater fluctuations in carbonate chemistry than previously thought.

Efficient data assimilation algorithm for bathymetry application

NASA Astrophysics Data System (ADS)

Ghorbanidehno, H.; Lee, J. H.; Farthing, M.; Hesser, T.; Kitanidis, P. K.; Darve, E. F.

2017-12-01

Information on the evolving state of the nearshore zone bathymetry is crucial to shoreline management, recreational safety, and naval operations. The high cost and complex logistics of using ship-based surveys for bathymetry estimation have encouraged the use of remote sensing techniques. Data assimilation methods combine the remote sensing data and nearshore hydrodynamic models to estimate the unknown bathymetry and the corresponding uncertainties. In particular, several recent efforts have combined Kalman Filter-based techniques such as ensembled-based Kalman filters with indirect video-based observations to address the bathymetry inversion problem. However, these methods often suffer from ensemble collapse and uncertainty underestimation. Here, the Compressed State Kalman Filter (CSKF) method is used to estimate the bathymetry based on observed wave celerity. In order to demonstrate the accuracy and robustness of the CSKF method, we consider twin tests with synthetic observations of wave celerity, while the bathymetry profiles are chosen based on surveys taken by the U.S. Army Corps of Engineer Field Research Facility (FRF) in Duck, NC. The first test case is a bathymetry estimation problem for a spatially smooth and temporally constant bathymetry profile. The second test case is a bathymetry estimation problem for a temporally evolving bathymetry from a smooth to a non-smooth profile. For both problems, we compare the results of CSKF with those obtained by the local ensemble transform Kalman filter (LETKF), which is a popular ensemble-based Kalman filter method.

Follow that fish: Uncovering the hidden blue economy in coral reef fisheries.

PubMed

Grafeld, Shanna; Oleson, Kirsten L L; Teneva, Lida; Kittinger, John N

2017-01-01

Despite their importance for human well-being, nearshore fisheries are often data poor, undervalued, and underappreciated in policy and development programs. We assess the value chain for nearshore Hawaiian coral reef fisheries, mapping post-catch distribution and disposition, and quantifying associated monetary, food security, and cultural values. We estimate that the total annual value of the nearshore fishery in Hawai'i is $10.3-$16.4 million, composed of non-commercial ($7.2-$12.9 million) and commercial ($2.97 million licensed + $148,500-$445,500 unlicensed) catch. Hawaii's nearshore fisheries provide >7 million meals annually, with most (>5 million) from the non-commercial sector. Over a third (36%) of meals were planktivores, 26% piscivores, 21% primary consumers, and 18% secondary consumers. Only 62% of licensed commercial catch is accounted for in purchase reports, leaving 38% of landings unreported in sales. Value chains are complex, with major buyers for the commercial fishery including grocery stores (66%), retailers (19%), wholesalers (14%), and restaurants (<1%), who also trade and sell amongst themselves. The bulk of total nearshore catch (72-74%) follows a short value chain, with non-commercial fishers keeping catch for household consumption or community sharing. A small amount (~37,000kg) of reef fish-the equivalent of 1.8% of local catch-is imported annually into Hawai'i, 23,000kg of which arrives as passenger luggage on commercial flights from Micronesia. Evidence of exports to the US mainland exists, but is unquantifiable given existing data. Hawaiian nearshore fisheries support fundamental cultural values including subsistence, activity, traditional knowledge, and social cohesion. These small-scale coral reef fisheries provide large-scale benefits to the economy, food security, and cultural practices of Hawai'i, underscoring the need for sustainable management. This research highlights the value of information on the value chain for small-scale production systems, making the hidden economy of these fisheries visible and illuminating a range of conservation interventions applicable to Hawai'i and beyond.

Temporal and geographic variation in fish communities of lower Cook Inlet, Alaska

USGS Publications Warehouse

Robards, Martin D.; Piatt, John F.; Kettle, Arthur B.; Abookire, Alisa A.

1999-01-01

Nearshore and shelf fish communities were studied in three areas of lower Cook Inlet, Alaska: the Barren Islands (oceanic and well-mixed waters), Kachemak Bay (mixed oceanic waters with significant freshwater runoff), and Chisik Island (estuarine waters). Fish were sampled with beach seines (n=413 sets) and midwater trawls (n=39 sets). We found that lower Cook Inlet supported a diverse nearshore fish community of at least 52 species. Fifty of these species were caught in Kachemak Bay, 24 at Chisik Island, and 12 at the Barren Islands. Pacific sand lance dominated Barren Islands and Kachemak Bay nearshore habitats, comprising 99% and 71% of total individuals, respectively. The nearshore Chisik Island fish community was not dominated by any one species; instead it exhibited higher diversity. These spatial differences appeared linked to local oceanographic regimes and sediment influx. Analysis of historical data revealed that the nearshore Kachemak Bay fish community changed significantly between 1976 and 1996, showing increased diversity and abundance in several taxa, notably gadids, salmonids, pleuronectids, and sculpins. Decadal differences appeared to be related to large-scale climate changes in the North Pacific. Catches of most taxa peaked in May-August, and were low during other months of the year. Several species were present for only part of the summer. Species composition of seine catches differed significantly between consecutive high and low tides, but not between consecutive sets or years. Midwater trawls took 26 species, 14 of which were present in Kachemak Bay, 19 near Chisik Island, and 7 at the Barren Islands. Community structures in shelf and nearshore waters were similar: diversity was high and abundance low at Chisik Island, whereas a few abundant species dominated at both Kachemak Bay and the Barren Islands. In addition, the low fish abundance near Chisik Island appeared to be related to declining seabird numbers at this colony.

Effect of transient wave forcing on the behavior of arsenic in a sandy nearshore aquifer

NASA Astrophysics Data System (ADS)

Rakhimbekova, S.; O'Carroll, D. M.; Robinson, C. E.

2016-12-01

Waves cause large quantities of coastal water to recirculate across the groundwater-coastal water interface in addition to inducing complex groundwater flows in the nearshore aquifer. Due to the distinct chemical composition of recirculating coastal water compared with discharging terrestrial groundwater, wave-induced recirculations and flows can alter geochemical gradients in the nearshore aquifer which may subsequently affect the mobilization and transport of reactive pollutants (e.g., arsenic). The impact of seasonal geochemical and hydrological variability on the occurrence and mobility of arsenic near the groundwater-surface water interface has been shown previously in riverine settings, however, the impact of high frequency geochemical variations (e.g., varying wave conditions) on arsenic mobility in groundwater-surface water environments is unclear. The objective of the study was to assess the impact of intensified wave conditions on the behavior of arsenic in a nearshore aquifer to determine the factors regulating its mobility and transport to receiving coastal waters. Field investigations were conducted at a permeable beach on the Great Lakes during a period of intensified wave conditions (wave event). High spatial resolution pore water sampling captured the geochemical conditions in the nearshore aquifer prior to the wave event, immediately after the wave event and over a recovery period of 3 weeks following the wave event. Shifts in pH and redox potential (ORP) gradients in response to varying wave conditions caused shifts in the iron and arsenic distributions in the aquifer. Sediment analysis was combined with the pore water distributions to assess the release of sediment-bound arsenic in response to the varying wave conditions. Insight into the effect of transient forcing on arsenic mobility and transport in groundwater-surface water environments is important for evaluating the potential risks associated with this toxic metalloid. The findings of this study also have significant implications for the fate of other reactive constituents (heavy metals, nutrients) discharging through nearshore aquifers to coastal waters.

Collapsing permafrost coasts in the Arctic

NASA Astrophysics Data System (ADS)

Fritz, Michael; Lantuit, Hugues

2017-04-01

Arctic warming is exposing permafrost coastlines, which account for 34% of the Earth's coasts, to rapid thaw and erosion. Coastal erosion rates as high as 25 m yr-1 together with the large amount of organic matter frozen in permafrost are resulting in an annual release of 14.0 Tg (1012 gram) particulate organic carbon into the nearshore zone. The nearshore zone is the primary recipient of higher fluxes of carbon and nutrients from thawing permafrost. We highlight the crucial role the nearshore zone plays in Arctic biogeochemical cycling, as here the fate of the released material is determined to: (1) degrade into greenhouse gases, (2) fuel marine primary production, (3) be buried in nearshore sediments or (4) be transported offshore. With Arctic warming, coastal erosion fluxes have the potential to increase by an order of magnitude until 2100. Such increases would result in drastic impacts on global carbon fluxes and their climate feedbacks, on nearshore food webs and on local communities, whose survival still relies on marine biological resources. Quantifying the potential impacts of increasing erosion on coastal ecosystems is crucial for food security of northern residents living in Arctic coastal communities. We need to know how the traditional hunting and fishing grounds might be impacted by high loads of sediment and nutrients released from eroding coasts, and to what extent coastal retreat will lead to a loss of natural habitat. Quantifying fluxes of organic carbon and nutrients is required, both in nearshore deposits and in the water column by sediment coring and systematic oceanographic monitoring. Ultimately, this will allow us to assess the transport and degradation pathways of sediment and organic matter derived from erosion. We need to follow the complete pathway, which is multi-directional including atmospheric release, lateral transport, transitional retention in the food web, and ultimate burial in seafloor sediments. We present numbers of multi-year dissolved organic matter (DOM) fluxes from coastal erosion into the nearshore zone of the southern Canadian Beaufort Sea. We further explore removal and degradation patterns of DOM based on oceanographic monitoring of coastal waters. Ultimately, we present accumulation rates and biogeochemical properties of marine sediment sequences drilled off the Yukon coast to track the pathways of the eroded material.

Submarine Groundwater Discharge and Fate Along the Coast of Kaloko-Honokohau National Historical Park, Island of Hawai`i; Part 3, Spatial and Temporal Patterns in Nearshore Waters and Coastal Groundwater Plumes, December 2003-April 2006

USGS Publications Warehouse

Grossman, Eric E.; Logan, Joshua B.; Presto, M. Katherine; Storlazzi, Curt D.

2010-01-01

During seven surveys between December 2003 and April 2006, 1,045 depth profiles of surface water temperature and salinity were collected to examine variability in water column properties and the influence of submarine groundwater discharge (SGD) on the nearshore waters and coral reef complex of Kaloko-Honokohau National Historical Park, Island of Hawai`i. This effort was made to characterize the variability in nearshore water properties with seasonality and hydrodynamic forcing (tides, winds, and waves) and to determine the spatial and vertical extent of influence of SGD plumes on the Park's marine biological resources. The results of this study reveal that nearshore waters of the Park were persistently influenced by plumes of submarine groundwater discharge that are generally colder, less saline, and more concentrated in nutrients than the surrounding seawater. These plumes extended between 100 and 1,000 m offshore to depths ranging between 1 and 5 m and often contained several million to hundreds of millions of gallons of brackish water. In essence, the Park's nearshore, like much of the arid west coast of Hawai`i, is estuarine. Although the groundwater plumes were persistent over the years studied, their spatial extent and volume varied tidally, seasonally, and annually. In one season, April 2004, an inverse relation of decreasing salinity with increasing temperature was found in the upper 5 m of the water column, unlike the other seasons, when surface water temperature and salinity were positively correlated. These data provide the first comprehensive record of nearshore water column properties within the Park boundaries and a baseline for detecting and assessing future conditions. Various resort, industrial, and municipal developments, either planned or under construction around the Park, will require significant groundwater supplies and will likely alter groundwater quantity and quality. The flux and quality of groundwater through the National Park are critical to the rare anchialine (brackish) pool ecosystems and various ecosystem functions of the nearshore waters and coral reefs. Changes in groundwater discharge are expected to have significant impacts to the area's coastal ecosystems, including decreased freshwater outflow to the brackish anchialine pools and coral reefs and increased nutrient and contaminant concentrations. In conjunction with two complementary studies of this series (Parts 1 and 2), these data provide insight into the patterns of influence and fate of SGD in the Park's coastal waters. This information is important for determining water-resource management strategies that balance the needs of the ecosystem with those of human livelihood. This report describes the data, presents the general findings, and gives representative examples of seasonal and tidal variability in water column properties and SGD-fed plumes across the Park's nearshore waters.

Use of radon-222 to evaluate the influence of groundwater discharge on fecal indicator bacteria concentrations in the near-shore ocean, Malibu, California

NASA Astrophysics Data System (ADS)

Izbicki, J. A.; Burton, C.; Swarzenski, P. W.

2011-12-01

To protect beach-goers from waterborne disease, California requires water-quality monitoring for fecal indicator bacteria (FIB) at beaches having more than 50,000 visits annually. The source(s) of FIB in ocean beaches in excess of marine recreational water standards is often not known, or may be incorrectly identified. Onsite wastewater treatment systems (OWTS) used to treat residential and commercial sewage have been implicated by regulatory agencies as a possible source of FIB to recreational ocean beaches, near Malibu, California. For this to occur, treated wastewater must first move through groundwater prior to discharge at the ocean. Groundwater discharge to the ocean near Malibu Lagoon (the estuary of Malibu Creek) is complicated by seasonally changing water levels in the lagoon. The lagoon is isolated from the ocean by a sand berm that develops across the mouth of the lagoon during the dry season. Higher water levels in the lagoon during the dry season, and lower water-levels during the wet season, cause seasonal changes in the direction of groundwater flow and the magnitude of discharge from the adjacent small (3,400 hectare), alluvial aquifer. Radon-222, an indicator of groundwater discharge, was measured in Malibu Lagoon, in the near-shore ocean adjacent to the lagoon, and in the near-shore ocean adjacent to unsewered residential development to determine the timing and magnitude of groundwater discharge. During the dry season, when the berm of the lagoon was closed and the lagoon was isolated from the ocean, radon-222 concentrations in the near-shore ocean during low tide increased as water discharged from the lagoon through the berm. Enterococcus concentrations in the near-shore ocean increased to almost 600 Most Probable Number (MPN) per 100 milliliter at this time. Radon-222 concentrations also increased at low tide as groundwater discharged to the ocean from the adjacent alluvial aquifer underlying the unsewered residential development, but there was no corresponding increase in FIB concentrations. In contrast, during the wet season when the berm of the lagoon was open, radon-222 data show groundwater discharge from the alluvial aquifer was primarily into the lagoon at low tide. The water in the lagoon was subsequently discharged directly to the near-shore ocean as a result of tidally driven circulation through the open berm. Radon-222 data showed little, if any, groundwater discharge to the near-shore ocean adjacent to the unsewered residential development at this time, implying that FIB in the near-shore ocean would not be derived from OWTS in the unsewered residential areas. The absence of FIB in recreational beaches adjacent to unsewered residential development at low tide suggests that mechanisms other than groundwater discharge may be responsible for high FIB concentrations in this area. For example, microbial communities sampled in the near-shore ocean were genetically similar to those present in kelp and different from OWTS samples-suggesting that high FIB concentrations, especially at high tide, may result from wave action on the beach releasing FIB entrained in kelp that was derived from birds and other non-human sources.

FINDING THE SCALES OF ECOLOGICAL RESPONSE TO LANDSCAPE CHARACTER AND TRIBUTARY INPUTS TO OPEN NEARSHORE WATERS, A GREAT LAKES COAST-WIDE EXPERIENCE

EPA Science Inventory

In 2002 we sampled over 40 stretches of open coastline across the US portion of the Great Lakes with an equal effort planned for 2003. Sites were selected to represent an intended gradient of landscape disturbance in watersheds hydrologically-connected to nearshore waters. Half t...

ASSESSING COASTAL WATERS OF AMERICAN SAMOA: TERRITORY-WIDE WATER QUALITY DATA PROVIDE A CRITICAL 'BIG-PICTURE' VIEW FOR THIS TROPICAL ARCHIPELAGO

EPA Science Inventory

The coastal waters of American Samoa’s 5 high islands (Tutuila, Aunu’u, Ofu, Olosega,and Ta’u) were surveyed in 2004 using a probabilistic design. Water quality data were collected from the near-shore coastal habitat, defined as all near-shore coastal waters including embayments,...

Development of DNA-based Identification methods to track the species composition of fish larvae within nearshore areas of the Great Lakes

EPA Science Inventory

The ability to track the identity and abundance of larval fish, which are ubiquitous during spawning season, may lead to a greater understanding of fish species distributions in Great Lakes nearshore areas including early-detection of invasive fish species before they become esta...

Is Littoral Habitat Affected by Residential Development and Land Use in Watersheds of Wisconsin Lakes?

Treesearch

Martin J. Jennings; Edward E. Emmons; Gene R. Hatzenbeler; Clayton Edwards; Michael A. Bozek

2003-01-01

We measured differences in nearshore littoral zone habitat among lakes with different amounts of residential development and different patterns of watershed land use. Sampling stations were located at randomly selected sites within the nearshore littoral zone of limnologically similar lakes. An index of development density (based on counts of residential structures)...

Shoreface response and recovery to Hurricane Sandy: Fire Island, NY

USGS Publications Warehouse

Nelson, Timothy R.; Hapke, Cheryl J.; Wang, Ping; Rosati, Julie D.; Cheng, Jun

2015-01-01

The shoreface of Fire Island was extensively modified by Hurricane Sandy and subsequent storms in the following winter months. The changes were evaluated using various morphometrics of the shoreface from four bathymetric surveys, one prior to Hurricane Sandy, and three over the course of twenty months following Sandy. The datasets show that the nearshore bar system moved offshore to deeper water depths following Hurricane Sandy with volume lost from the subaerial beach and surfzone. Following the offshore shift, the nearshore bar system increased in size, the trough deepened, and there has been gradual landward movement of the nearshore bar. The steepening of the upper shoreface, landward translation of the profile, and loss of sediment is indicative of barrier island transgression.

Impacts of a North Pacific Predator on Nearshore Seawater Mercury Cycling via Top-Down Contamination

NASA Astrophysics Data System (ADS)

Cossaboon, J. M.; Ganguli, P. M.; Flegal, A. R., Jr.

2015-12-01

Marine mammals are common sentinel species for studying marine pollution, however their potential role as vectors of contaminants to local ecosystems has rarely been addressed. Organic methylmercury, or MeHg, is a potent neurotoxin that biomagnifies approximately one to ten million-fold in aquatic carnivores such as the Northern elephant seal (Mirounga angustirostris), whose excreta and molted pelage, in turn, constitute a source of environmental MeHg contamination at the base of marine food chains. This recycling of MeHg was evidenced by comparing total mercury (HgT) and MeHg concentrations in seawater at the Año Nuevo State Reserve pinniped rookery to those of neighboring coastal sites in Central California. The observed 17-fold enrichment of MeHg in seawater at Año Nuevo during the M. angustirostris molting season (0.28—9.5 pM) was remarkable, and exceeded the range of surface water MeHg concentrations observed in the highly urbanized San Francisco Bay estuary (<0.05—2.3 pM). The importance of MeHg inputs to Año Nuevo waters from Northern elephant seals was confirmed by the HgT concentrations in molted pelage samples (average = 3.6 μg g-1 dry wt.), which presumably contained >80% MeHg. This equates to an annual per-capita emission factor of 0.05 g MeHg per adult elephant seal. Based on this estimate, we calculate that approximately 0.2 kg of organic Hg entered the nearshore environment of Año Nuevo during that molting season. This elevated methylmercury (MeHg) in seawater adjacent to the rookery may become bioavailable to lower trophic levels, demonstrating that marine mammal colonization can substantially influence nearshore mercury cycling and potentially threaten ecosystem health.

Migratory corridors of adult female Kemp’s ridley turtles in the Gulf of Mexico

USGS Publications Warehouse

Shaver, Donna J.; Hart, Kristen M.; Fujisaki, Ikuko; Rubio, Cynthia; Sartain-Iverson, Autumn R.; Pena, Jaime; Gamez, Daniel Gomez; Gonzales Diaz Miron, Raul de Jesus; Burchfield, Patrick M.; Martinez, Hector J.; Ortiz, Jaime

2016-01-01

For many marine species, locations of migratory pathways are not well defined. We used satellite telemetry and switching state-space modeling (SSM) to define the migratory corridor used by Kemp's ridley turtles (Lepidochelys kempii) in the Gulf of Mexico. The turtles were tagged after nesting at Padre Island National Seashore, Texas, USA from 1997 to 2014 (PAIS; n = 80); Rancho Nuevo, Tamaulipas, Mexico from 2010 to 2011 (RN; n = 14); Tecolutla, Veracruz, Mexico from 2012 to 2013 (VC; n = 13); and Gulf Shores, Alabama, USA during 2012 (GS; n = 1). The migratory corridor lies in nearshore Gulf of Mexico waters in the USA and Mexico with mean water depth of 26 m and a mean distance of 20 km from the nearest mainland coast. Migration from the nesting beach is a short phenomenon that occurs from late-May through August, with a peak in June. There was spatial similarity of post-nesting migratory pathways for different turtles over a 16 year period. Thus, our results indicate that these nearshore Gulf waters represent a critical migratory habitat for this species. However, there is a gap in our understanding of the migratory pathways used by this and other species to return from foraging grounds to nesting beaches. Therefore, our results highlight the need for tracking reproductive individuals from foraging grounds to nesting beaches. Continued tracking of adult females from PAIS, RN, and VC nesting beaches will allow further study of environmental and bathymetric components of migratory habitat and threats occurring within our defined corridor. Furthermore, the existence of this migratory corridor in nearshore waters of both the USA and Mexico demonstrates that international cooperation is necessary to protect essential migratory habitat for this imperiled species.

Inter-nesting movements and habitat-use of adult female Kemp’s ridley turtles in the Gulf of Mexico

USGS Publications Warehouse

Shaver, Donna J.; Hart, Kristen M.; Fujisaki, Ikuko; Bucklin, David N.; Iverson, Autumn; Rubio, Cynthia; Backof, Thomas F.; Burchfield, Patrick M.; Gonzales Diaz Miron, Raul de Jesus; Dutton, Peter H.; Frey, Amy; Peña, Jaime; Gamez, Daniel Gomez; Martinez, Hector J.; Ortiz, Jaime

2017-01-01

Species vulnerability is increased when individuals congregate in restricted areas for breeding; yet, breeding habitats are not well defined for many marine species. Identification and quantification of these breeding habitats are essential to effective conservation. Satellite telemetry and switching state-space modeling (SSM) were used to define inter-nesting habitat of endangered Kemp’s ridley turtles (Lepidochelys kempii) in the Gulf of Mexico. Turtles were outfitted with satellite transmitters after nesting at Padre Island National Seashore, Texas, USA, from 1998 through 2013 (n = 60); Rancho Nuevo, Tamaulipas, Mexico, during 2010 and 2011 (n = 11); and Tecolutla, Veracruz, Mexico, during 2012 and 2013 (n = 11). These sites span the range of nearly all nesting by this species. Inter-nesting habitat lies in a narrow band of nearshore western Gulf of Mexico waters in the USA and Mexico, with mean water depth of 14 to 19 m within a mean distance to shore of 6 to 11 km as estimated by 50% kernel density estimate, α-Hull, and minimum convex polygon methodologies. Turtles tracked during the inter-nesting period moved, on average, 17.5 km/day and a mean total distance of 398 km. Mean home ranges occupied were 725 to 2948 km2. Our results indicate that these nearshore western Gulf waters represent critical inter-nesting habitat for this species, where threats such as shrimp trawling and oil and gas platforms also occur. Up to half of all adult female Kemp’s ridleys occupy this habitat for weeks to months during each nesting season. Because inter-nesting habitat for this species is concentrated in nearshore waters of the western Gulf of Mexico in both Mexico and the USA, international collaboration is needed to protect this essential habitat and the turtles occurring within it.

Inter-nesting movements and habitat-use of adult female Kemp's ridley turtles in the Gulf of Mexico.

PubMed

Shaver, Donna J; Hart, Kristen M; Fujisaki, Ikuko; Bucklin, David; Iverson, Autumn R; Rubio, Cynthia; Backof, Thomas F; Burchfield, Patrick M; de Jesus Gonzales Diaz Miron, Raul; Dutton, Peter H; Frey, Amy; Peña, Jaime; Gomez Gamez, Daniel; Martinez, Hector J; Ortiz, Jaime

2017-01-01

Species vulnerability is increased when individuals congregate in restricted areas for breeding; yet, breeding habitats are not well defined for many marine species. Identification and quantification of these breeding habitats are essential to effective conservation. Satellite telemetry and switching state-space modeling (SSM) were used to define inter-nesting habitat of endangered Kemp's ridley turtles (Lepidochelys kempii) in the Gulf of Mexico. Turtles were outfitted with satellite transmitters after nesting at Padre Island National Seashore, Texas, USA, from 1998 through 2013 (n = 60); Rancho Nuevo, Tamaulipas, Mexico, during 2010 and 2011 (n = 11); and Tecolutla, Veracruz, Mexico, during 2012 and 2013 (n = 11). These sites span the range of nearly all nesting by this species. Inter-nesting habitat lies in a narrow band of nearshore western Gulf of Mexico waters in the USA and Mexico, with mean water depth of 14 to 19 m within a mean distance to shore of 6 to 11 km as estimated by 50% kernel density estimate, α-Hull, and minimum convex polygon methodologies. Turtles tracked during the inter-nesting period moved, on average, 17.5 km/day and a mean total distance of 398 km. Mean home ranges occupied were 725 to 2948 km2. Our results indicate that these nearshore western Gulf waters represent critical inter-nesting habitat for this species, where threats such as shrimp trawling and oil and gas platforms also occur. Up to half of all adult female Kemp's ridleys occupy this habitat for weeks to months during each nesting season. Because inter-nesting habitat for this species is concentrated in nearshore waters of the western Gulf of Mexico in both Mexico and the USA, international collaboration is needed to protect this essential habitat and the turtles occurring within it.

Dynamic groundwater flows and geochemistry in a sandy nearshore aquifer over a wave event

NASA Astrophysics Data System (ADS)

Malott, Spencer; O'Carroll, Denis M.; Robinson, Clare E.

2016-07-01

Dynamic coastal forcing influences the transport of pollutants in nearshore aquifers and their ultimate flux to coastal waters. In this study, field data are presented that show, for the first time, the influence of a period of intensified wave conditions (wave event) on nearshore groundwater flows and geochemistry in a sandy beach. Field measurements at a freshwater beach allow wave effects to be quantified without other complex forcing that are present along marine shorelines (e.g., tides). Pressure transducer data obtained over an isolated wave event reveal the development of transient groundwater flow recirculations. The groundwater flows were simulated in FEFLOW using a phase-averaged wave setup approach to represent waves acting on the sediment-water interface. Comparison of measured and simulated data indicates that consideration of wave setup alone is able to adequately capture wave-induced perturbations in groundwater flows. While prior studies have shown sharp pH and redox spatial zonations in nearshore aquifers, this study reveals rapid temporal variations in conductivity, pH, and redox (ORP) in shallow sediments (up to 0.5 m depth) in response to varying wave conditions. Comparison of head gradients with calculated conductivity and pH mixing ratios indicates the controlling effect of the wave-induced water exchange and flows in driving the observed geochemical dynamics. While we are not able to conclusively determine the extent to which temporal variations are caused by conservative mixing versus reactive processes, the pH and ORP variations observed will have significant implications for the fate of reactive pollutants discharging through sandy nearshore aquifers.

Nearshore Satellite Data as Relative Indicators of Intertidal Organism Physiological Stress

NASA Astrophysics Data System (ADS)

Matzelle, A.; Helmuth, B.; Lakshmi, V.

2011-12-01

The physiological performance of intertidal and shallow subtidal invertebrates and algae is significantly affected by water temperature, and so the ability to measure and model onshore water temperatures is critical for ecological and biogeographic studies. Because of the localized influences of processes such as upwelling, mixing, and surface heating from solar radiation, nearshore water temperatures can differ from those measured directly offshore by buoys and satellites. It remains an open question what the magnitude of the differences in these temperatures are, and whether "large pixel" measurements can serve as an effective proxy for onshore processes, particularly when extrapolating from laboratory physiological studies to field conditions. We compared 9 years of nearshore (~10km) MODIS (Terra and Aqua overpasses) SST data against in situ measurements of water temperature conducted at two intertidal sites in central Oregon- Boiler Bay and Strawberry Hill. We collapsed data into increasingly longer temporal averages to address the correlation and absolute differences between onshore and nearshore temperatures over daily, weekly and monthly timescales. Results indicate that nearshore SST is a reasonable proxy for onshore water temperature, and that the strength of the correlation increases with decreasing temporal resolution. Correlations between differences in maxima are highest, followed by average and minima, and were lower at a site with regular upwelling. While average differences ranged from ~0.199-1.353°C, absolute differences across time scales were ~0.446-6.906°C, and were highest for cold temperatures. The results suggest that, at least at these two sites, SST can be used as a relative proxy for general trends only, especially over longer time scales.

Living Rocks in Connecticut River Headwaters: Ferromanganese Stromatolites

NASA Astrophysics Data System (ADS)

Asikainen, C. A.

2006-12-01

Fossil microbialites abound from the Archean Eon (>3.5 x 102 years before present) until the Holocene and provide a major source of information about early life on Earth; living examples available to study are rare. Such structures are known from both marine and lacustrine environments world-wide and are composed of microbially-mediated deposition of iron and manganese oxide minerals. We discovered ferromanganese nodules with stromatolitic growth patterns in the western near-shore portion of Second Connecticut Lake, New Hampshire, United States. One of the three headwater lakes of the Connecticut River that extends from the United States/Canadian border to Long Island Sound, Second Connecticut Lake is located in the northern woods region of New Hampshire and covers an area of 5,204 km2. These three lakes were formed during the retreat of the Laurentide Ice sheet nearly 12,000 years ago, following the Last Glacial Maximum. The ferromanganese nodules found in Second Connecticut Lake form irregular but concentric rings around a central "nucleus" such as a pebble or cobble. Although similar structures are described in freshwater systems (e.g. Lake Oneida, New York and Lake Vermillion, Minnesota) the others lack the variety of morphologies, range of size distribution and continuous pavement coverage of those in the Second Connecticut Lake; and none has been reported from any of the six New England States. The most conspicuous and abundant of the four distinct morphotypes are a convex plate-like structure that forms concentric rings around a central nucleus such as a stone. They are supplemented by pavement-type, lattice-type, and tiny (<2 cm) variously shaped nodule structures. Comparable freshwater structures range from 5 to 20 cm in diameter whereas our individual nodules measure up to 43 cm and cover an area of 9.8 km2. Thus, these Second Connecticut Lake structures represent the most extensive living fresh water nodule deposit reported.

Key challenges of offshore wind power: Three essays addressing public acceptance, stakeholder conflict, and wildlife impacts

NASA Astrophysics Data System (ADS)

Bates, Alison Waterbury

Society is facing a pressing need to reduce greenhouse gas emissions to limit anthropogenic climate change, which has far reaching implications for humans and the environment. Transforming the energy infrastructure to carbon-free sources is one solution to curb greenhouse gas emissions, but this transformation has been slow to materialize in many places, such as the United States (U.S.). Offshore wind energy is one of the most promising renewable energy sources available, which can be deployed in large-scale developments in many parts of the world. Yet, offshore wind has faced many challenges, which are more social and regulatory than technical. This dissertation addresses social and regulatory issues surrounding offshore wind development through three stand-alone essays, which, in combination, address a decision-making framework of where to locate offshore wind turbines, by minimizing effects on people and wildlife. The challenges to offshore wind that are addressed by this dissertation include (1) understanding underlying factors that drive support for or opposition to offshore wind energy; (2) conflict with existing ocean uses and users; and (3) public concern and regulatory processes related to wildlife impacts. The first paper identifies unique factors that drive public opinion of proposed offshore wind projects in nearby coastal communities. Wind energy development on land has faced local opposition for reasons such as effects on cultural landscapes and wildlife, which can be instrumental in whether or not and the speed with which a project moves ahead toward completion. Factors leading to support for, or opposition to, offshore wind energy are not well known, particularly for developments that are near-shore and in-view of coastal communities. Results are presented from a survey of 699 residents (35.5% response rate) completed in 2013 in greater Atlantic City, New Jersey and coastal Delaware, United States, where near-shore wind demonstration projects had been proposed. The essay examines how the public considers the societal tradeoffs that are made to develop small-scale, in-view demonstration wind projects instead of larger facilities farther offshore. Results indicate that a strong majority of the public supports near-shore demonstration wind projects in both states. Primary reasons for support include benefits to wildlife, cost of electricity, and job creation, while the primary reasons for opposition include wildlife impacts, aesthetics, tourism, and user conflicts. These factors differ between coastal Delaware and greater Atlantic City and highlight the importance of local, community engagement in the early stages of development. The second essay examines the interaction of a new proposed use of the ocean---offshore wind---and a key existing ocean user group---commercial fishers. A key component of offshore wind planning includes consideration of existing uses of the marine environment in order to optimally site wind projects while minimizing conflicts. Commercial fisheries comprise an important stakeholder group, and may be one of the most impacted stakeholders from offshore renewable energy development. Concern of the fishing industry stems from possible interference with productive fishing grounds and access within wind developments resulting in costs from increased effort or reduction in catch. Success of offshore wind development may in part depend on the acceptance of commercial fishers, who are concerned about loss of access to fishing grounds. Using a quantitative, marine spatial planning approach in the siting of offshore wind projects with respect to commercial fishing in the mid-Atlantic, U.S., this essay develops a spatially explicit representation of potential conflicts and compatibilities between these two industries in the mid-Atlantic region of the United States. Areas that are highly valuable to the wind industry are determined through a spatial suitability model using variable cost per unit energy. Areas that are highly valuable to the fishing industry are determined by examining fishing effort in three high-value fishing sectors (sea scallops, clam fisheries, and high-value mobile fisheries). Ultimately, the results identify locations where the industries are conflicting and where they are compatible. This quantitative analysis of the potential tradeoffs between the commercial fishing industry and offshore wind development benefits wind developers, states, and federal regulators by helping advance offshore wind power to meet national priorities. Finally, the third essay addresses wildlife impacts through a comprehensive review of the impacts to marine mammals and the regulatory context to manage these impacts. Regulators, scientists, and stakeholders are interested in the potential impacts from pre-construction surveys, turbine installation, operation and maintenance, and decommissioning of offshore wind sites. This article reviews both commissioned reports and peer-reviewed literature to provide a comprehensive overview of the expected impacts of offshore wind energy to marine mammals. Impacts include noise, which is generated during three stages of development: investigation/construction, operation, and decommissioning. Additional potential effects arise from electromagnetic fields, changes in prey abundance and distribution, and the creation of artificial reefs and 'de-facto' marine protected areas. Because offshore wind power may also deliver substantial long-term benefits to wildlife and humans in the form of reduced CO2 emissions, implementation of mitigation measures to reduce negative impacts to marine mammals may be a plausible option to help this industry advance. An overview of mitigation options is reviewed, as well as the legal framework protecting marine mammals from anthropogenic impacts. Finally, the essay makes several recommendations where government and wind developers can improve research and regulatory processes to increase efficiency and streamline the application and review process.

Covariance Function for Nearshore Wave Assimilation Systems

DTIC Science & Technology

2018-01-30

covariance can be modeled by a parameterized Gaussian function, for nearshore wave assimilation applications, the covariance function depends primarily on...case of missing values at the compiled time series, the gaps were filled by weighted interpolation. The weights depend on the number of the...averaging, in order to create the continuous time series, filters out the dependency on the instantaneous meteorological and oceanographic conditions

Application of remote sensing to study nearshore circulation. [and the continental shelf

NASA Technical Reports Server (NTRS)

Zeigler, J.; Lobecker, R.; Stauble, D.; Welch, C.; Haas, L.; Fang, C. S.

1974-01-01

The research to use remote sensing techniques for studying the continental shelf is reported. The studies reported include: (1) nearshore circulation in the vincinity of a natural tidal inlet; (2) identification of indicators of biological activity; (3) remote navigation system for tracking free drifting buoys; (4) experimental design of an estuaring tidal circulation; and (5) Skylab support work.

50 CFR 697.26 - EEZ Nearshore Management Area 5 Trap Waiver.

Code of Federal Regulations, 2013 CFR

2013-10-01

... permit under this section may engage in trap fishing for black sea bass in EEZ Nearshore Management Area... applicable to lobster and black sea bass fishing. (1) A vessel issued a permit under this section may retain... sea bass permits under § 648.4(a)(7)(i) of this chapter may request an Area 5 Trap Waiver Permit...

50 CFR 697.26 - EEZ Nearshore Management Area 5 Trap Waiver.

Code of Federal Regulations, 2014 CFR

2014-10-01

... permit under this section may engage in trap fishing for black sea bass in EEZ Nearshore Management Area... applicable to lobster and black sea bass fishing. (1) A vessel issued a permit under this section may retain... sea bass permits under § 648.4(a)(7)(i) of this chapter may request an Area 5 Trap Waiver Permit...

50 CFR 697.26 - EEZ Nearshore Management Area 5 Trap Waiver.

Code of Federal Regulations, 2012 CFR

2012-10-01

... permit under this section may engage in trap fishing for black sea bass in EEZ Nearshore Management Area... applicable to lobster and black sea bass fishing. (1) A vessel issued a permit under this section may retain... sea bass permits under § 648.4(a)(7)(i) of this chapter may request an Area 5 Trap Waiver Permit...

Coastal habitats in Puget Sound: A research plan in support of the Puget Sound Nearshore Partnership

USGS Publications Warehouse

Gelfenbaum, Guy; Mumford, Tom; Brennan , Jim; Case, Harvey; Dethier, Megan; Fresh, Kurt; Goetz, Fred; van Heeswijk, Marijke; Leschine, Thomas M.; Logsdon, Miles; Myers, Doug; Newton, Jan; Shipman, Hugh; Simenstad, Charles A.; Tanner, Curtis; Woodson, David

2006-01-01

The purpose of this research plan is to identify high-priority research goals and objectives and delineate the critical questions and information gaps that need to be addressed to provide natural-resource managers and policy- and decisionmakers with tools to effectively undertake restoration planning and adaptive management of the nearshore ecosystems of Puget Sound.

Spatiotemporal Variation of Arctic Nearshore Fish Communities in Barrow, AK

NASA Astrophysics Data System (ADS)

Boswell, K. M.; Barton, M. B.; Lemoine, N. P.; Heintz, R.; Vollenweider, J.; Norcross, B.; Sousa, L.

2016-02-01

Climate change, oil and gas development, and increased transportation opportunities associated with retreating sea ice cover are likely to affect the processes underlying community development. Unfortunately, there is a paucity of information that prohibits establishing a baseline from which to examine biological and ecological changes. To address these concerns, we developed an intensive field sampling program using weekly beach seining for the six weeks following land-fast ice break-up during the summers of 2013-2015 (183 beach seine hauls totaling 37,303 fish) in three distinct water masses near Pt. Barrow, Alaska to examine how fish communities develop in the Arctic nearshore. Preliminary analyses indicate that inter-annual variability in temperature and salinity influence species composition observed in late summer, but it is unclear which factors operate on smaller temporal scales. We applied multivariate variance partitioning to quantify variation in community structure on multiple spatial and temporal scales during the summer season and identified several physicochemical parameters as important spatiotemporal drivers in structuring nearshore fish communities. Understanding how these drivers affect nearshore communities on the seasonal scale is an integral step to predict how these ecologically important ecosystems may shift in the face of Arctic climate change and continued development.

Terrestrial organic matter as subsidies that aid in the recovery of macroinvertebrates in industrially damaged lakes.

PubMed

Szkokan-Emilson, E J; Wesolek, B E; Gunn, J M

2011-09-01

The importance of allochthonous carbon to the productivity of stream ecosystems in temperate ecozones is well understood, but this relationship is less established in oligotrophic lakes. The nearshore littoral zones, at the interface of terrestrial and aquatic systems, are areas where the influence of terrestrial subsidies is likely greatest. We investigated the response of nearshore communities to variation in the quantity and composition of allochthonous materials, determined the landscape characteristics that regulate the variation of this subsidy, and explored the potential for terrestrial restoration practices to influence the export of organic matter to lakes. Stepwise multiple regressions revealed that diversity of nearshore macroinvertebrate families increased with the amount of fine particulate organic matter (FPOM) captured in sediment traps. The quantity of FPOM (g) increased with forest cover, and the relative amount of FPOM (percentage of total particulate material) in the traps increased with surface area of wetland in the catchments. These models suggest that terrestrially derived subsidies are important in smelter-impacted watersheds, and that the restoration of forests and wetlands will speed the return of nearshore consumer community diversity in industrially damaged lakes.

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

Davis, R.J.; Johnson, C.A.; Gilreath, J.A.

Depositional systems in the Medina Group (Lower Silurian) of western New York have been studied using stratigraphic dipmeter data. Results of this study indicate a nearshore-deltaic-interdeltaic depositional environment. Only minor deltaic episodes are preserved in the study area. This fits the generally arid climate with seasonal wet periods suggested by C.D. Laughrey. Facies recognized include: longshore-current sand waves in a shoreface environment, distributary mouth bars, distributary channels, tidal inlets, flood deltas, beaches, sandy tidal flats on which beach ridges were formed, and possible upper delta-plain sediments. Once the depositional sequences are recognized, paleocurrents within key sand units can be interpretedmore » to determine favorable directions for successfully locating offset wells.« less

Map showing distribution of small-scale deformation structures in a part of the upper coastal plain of South Carolina and adjacent Georgia

USGS Publications Warehouse

McDowell, R.C.; Houser, B.B.

1983-01-01

Fieldwork was done principally by vehicle along roads, but also included railroad cuts and excavation sites, such as quarries and landfills. Natural exposures are rare and provided no examples of deformation structures for this study. The geologic units exposed in the area are chiefly clastic sediments deposited in nearshore marine to continental environments. They include semi-consolidated sand, silt, clay, and rare thin impure limestone beds of Late Cretaceous to Eocene age (fig. 2). These sedimentary beds generally have a gentle regional dip to the southeast (Faye and Prowell, 1982, p. 6).

Song recorded near a super-group of humpback whales on a mid-latitude feeding ground off South Africa.

PubMed

Gridley, T; Silva, M F P; Wilkinson, C; Seakamela, S M; Elwen, S H

2018-04-01

Humpback whales (Megaptera novaeangliae) are well known for their complex song which is culturally transmitted and produced by males. However, the function of singing behavior remains poorly understood. Song was observed from 57 min of acoustic recording in the presence of feeding humpback whales aggregated in the near-shore waters on the west coast of South Africa. The structural organization of the song components, lack of overlap between song units, and consistency in relative received level suggest the song was produced by one "singer." The unusual timing and location of song production adds further evidence of plasticity in song production.

Species profiles: life histories and environmental requirements of coastal fishes and invertebrates (South Atlantic) - Atlantic sturgeon

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

Van Den Avyle, M.J.

1984-07-01

The Atlantic sturgeon, Acipenser oxyrhynchus oxyrhynchus, is an anadromous species that occupies rivers, estuaries, and nearshore waters along the entire Atlantic coast of the United States. The species once supported significant commercial fisheries throughout its range, but stocks have declined because of overfishing, deterioration of water quality, and damming of rivers. Atlantic sturgeon spawn in rivers and the young remain in freshwater for several years prior to emigration to the ocean. Little is known about spawning areas and associated environmental factors. Females typically do not mature until age X and the age at first spawning ranges from 5 to 13more » years for males and 7 to 19 years for females. Longevity may frequently exceed 25 years. Immature and adult sturgeons are bottom feeders and consume a variety of mollusks, crustaceans, worms, and other small bottom-dwelling invertebrates and fishes. Little is know about competitors, predators, or effects of environmental factors on recruitment. The long period required to reach maturity, possibly irregular spawning thereafter, and prolonged reliance on river systems make juvenile and adult Atlantic sturgeon highly susceptible to habitat alterations, pollution, and over exploitation. 49 references, 2 figures, 4 tables.« less

78 FR 43005 - Endangered and Threatened Species: Designation of Critical Habitat for the Northwest Atlantic...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-18

...We, the National Marine Fisheries Service (NMFS), propose critical habitat for the Northwest Atlantic Ocean loggerhead sea turtle Distinct Population Segment (DPS) (Caretta caretta) within the Atlantic Ocean and the Gulf of Mexico. Specific areas proposed for designation include 36 occupied marine areas within the range of the Northwest Atlantic Ocean DPS. These areas contain one or a combination of nearshore reproductive habitat, winter area, breeding areas, and migratory corridors. We are also asking for comment on whether to include as critical habitat in the final rule some areas that contain foraging habitat and two large areas that contain Sargassum habitat. The U.S. Fish and Wildlife Service addressed terrestrial areas (nesting beaches) in a separate document. No marine areas meeting the definition of critical habitat were identified within the jurisdiction of the United States for the North Pacific Ocean DPS, and therefore we are not proposing to designate critical habitat for that DPS. We are soliciting comments from the public on all aspects of the proposal, including information on the economic, national security, and other relevant impacts. We will consider additional information received prior to making a final designation.

Habitat associations of marbled murrelets during the nesting season in nearshore waters along the Washington to California coast

Treesearch

Martin G. Raphael; Andrew J. Shirk; Gary A. Falxa; Scott F. Pearson

2015-01-01

The marbled murrelet (Brachyramphus marmoratus) is a seabird in the family Alcidae that forages in nearshore waters of the Pacific Northwest, and nests in adjacent older-forest conifers within 80 km offshore. The species is of conservation concern due to habitat loss and declining numbers, and is listed as Threatened in British Columbia, Canada and...

Follow that fish: Uncovering the hidden blue economy in coral reef fisheries

PubMed Central

Teneva, Lida; Kittinger, John N.

2017-01-01

Despite their importance for human well-being, nearshore fisheries are often data poor, undervalued, and underappreciated in policy and development programs. We assess the value chain for nearshore Hawaiian coral reef fisheries, mapping post-catch distribution and disposition, and quantifying associated monetary, food security, and cultural values. We estimate that the total annual value of the nearshore fishery in Hawaiʻi is $10.3-$16.4 million, composed of non-commercial ($7.2-$12.9 million) and commercial ($2.97 million licensed + $148,500-$445,500 unlicensed) catch. Hawaii’s nearshore fisheries provide >7 million meals annually, with most (>5 million) from the non-commercial sector. Over a third (36%) of meals were planktivores, 26% piscivores, 21% primary consumers, and 18% secondary consumers. Only 62% of licensed commercial catch is accounted for in purchase reports, leaving 38% of landings unreported in sales. Value chains are complex, with major buyers for the commercial fishery including grocery stores (66%), retailers (19%), wholesalers (14%), and restaurants (<1%), who also trade and sell amongst themselves. The bulk of total nearshore catch (72–74%) follows a short value chain, with non-commercial fishers keeping catch for household consumption or community sharing. A small amount (~37,000kg) of reef fish—the equivalent of 1.8% of local catch—is imported annually into Hawaiʻi, 23,000kg of which arrives as passenger luggage on commercial flights from Micronesia. Evidence of exports to the US mainland exists, but is unquantifiable given existing data. Hawaiian nearshore fisheries support fundamental cultural values including subsistence, activity, traditional knowledge, and social cohesion. These small-scale coral reef fisheries provide large-scale benefits to the economy, food security, and cultural practices of Hawaiʻi, underscoring the need for sustainable management. This research highlights the value of information on the value chain for small-scale production systems, making the hidden economy of these fisheries visible and illuminating a range of conservation interventions applicable to Hawaiʻi and beyond. PMID:28771508

Do rivermouths alter nutrient and seston delivery to the nearshore?

USGS Publications Warehouse

Larson, James H.; Frost, Paul C.; Vallazza, Jon M.; Nelson, John; Richardson, William B.

2016-01-01

Tributary inputs to lakes and seas are often measured at riverine gages, upstream of lentic influence. Between these riverine gages and the nearshore zones of large waterbodies lie rivermouths, which may retain, transform and contribute materials to the nearshore zone. However, the magnitude and timing of these rivermouth effects have rarely been measured.During the summer of 2011, 23 tributary systems of the Laurentian Great Lakes were sampled from river to nearshore for dissolved and particulate carbon (C), nitrogen (N) and phosphorus (P) concentrations, as well as bulk seston and chlorophyll a concentrations. Three locations per system were sampled: in the upstream river, in the nearshore zone and at the outflow from the rivermouth to the lake. Using stable oxygen isotopes, a water-mixing model was developed to estimate the nutrient concentration that would occur at the rivermouth if mixing was strictly conservative (i.e. if no processing occurred within the rivermouth). Deviations between these conservative mixing estimates and measured nutrient concentrations were identified as rivermouth effects on nutrient concentrations.Rivermouths had higher concentration of C and P than nearshore areas and more chlorophyll athan upstream river waters. Compared to the conservative mixing model, rivermouths as a class appeared to be summer-time sources of N, P and chlorophyll a. Substantial among rivermouth variation occurred both in the effect size and direction for all constituents.Using principal component analysis, two groups of rivermouths were identified: rivermouths that had a large effect on most constituents and those that had very little effect on any of the measured constituents. ‘High-effect’ rivermouths had more abundant upstream croplands, which were presumably the sources of inorganic nutrients. Cross-validated models built using characteristics of the rivermouth were not good predictors of variation in rivermouth effects on most constituents.For consumers feeding on seston and microbes and vascular autotrophs directly taking up dissolved nutrients, rivermouths are more resource-rich than upstream riverine or nearby Great Lakes waters. Given declines over time in open-lake productivity within the Great Lakes, rivermouths may contribute more productivity than their size would suggest to the Great Lakes food web.

Practitioners' views of science needs for the Great Lakes coastal ecosystem

USGS Publications Warehouse

Pebbles, Victoria; Lillard, Elizabath C.; Seelbach, Paul W.; Fogarty, Lisa Reynolds

2015-01-01

In 2014, the U.S. Geological Survey Great Lake Science Center (USGS-GLSC) and the USGS-Michigan Water Science Center partnered with the Great Lakes Commission (GLC) to conduct a series of four workshops with coastal practitioners and managers across the Great Lakes basin to highlight the need for, and get input on, a Great Lakes regional coastal science strategy. To this end, this report is intended to help guide USGS coastal and nearshore science priorities, but may also help guide other science agencies. The USGS-GLSC partnership on this effort was part of a broader five-year Memorandum of Understanding between the USGS-GLSC and the GLC to enhance communications between coastal science and management communities within the Great Lakes region. This report presents a summary and analysis of participant feedback from the four workshops held in 2014. Participant feedback included participant worksheets as well as interactive drawing sessions, individual notes and group flip chart notes from each workshop. The results are presented as a series of findings that can be used to guide USGS coastal/nearshore science priorities in support of management needs at local, state and regional scales.

Nearshore hydrodynamics at pocket beaches with contrasting wave exposure in southern Portugal

NASA Astrophysics Data System (ADS)

Horta, João; Oliveira, Sónia; Moura, Delminda; Ferreira, Óscar

2018-05-01

Pocket beaches on rocky coasts with headlands that control hydro-sedimentary processes are considered to be constrained sedimentary systems, generally with limited sediment inputs. Pocket beaches face severe changes over time. Under worst-case scenarios, these changes can result in the loss of the beach, causing waves to directly attack adjacent cliffs. Studies of nearshore hydrodynamics can help to understand such changes and optimise sediment nourishment procedures. The present work contributes to the knowledge of hydrodynamic forcing mechanisms at pocket beaches by providing a comprehensive description of the nearshore circulation at two beaches with contrasting wave exposures. Two pocket beaches in southern Portugal were studied by combining field measurements of waves and currents with numerical models (STWAVE and BOUSS-2D). The aim of this analysis was to evaluate nearshore hydrodynamics under different wave exposure forcing conditions (e.g. variable wave heights/directions and different tidal levels). The results show that the beach circulation can rapidly shift from longshore-to rip-dominated depending on changes in both the offshore wave direction and tidal levels. Waves with higher obliquity (for both low and moderate wave energy conditions) tend to generate longshore circulation in all considered tidal stages, while waves with lower obliquity tend to produce rip flow with higher-velocity rip currents during low to intermediate tidal stages. The results indicate that the location and intensity of rip currents strongly depend on geomorphological constraints, that is, the control exerted by shore platforms. A larger morphological control is observed at mean sea level because most platforms are submerged/exposed during high/low tide and therefore exert less control on nearshore circulation.

Modeling long period swell in Southern California: Practical boundary conditions from buoy observations and global wave model predictions

NASA Astrophysics Data System (ADS)

Crosby, S. C.; O'Reilly, W. C.; Guza, R. T.

2016-02-01

Accurate, unbiased, high-resolution (in space and time) nearshore wave predictions are needed to drive models of beach erosion, coastal flooding, and alongshore transport of sediment, biota and pollutants. On highly sheltered shorelines, wave predictions are sensitive to the directions of onshore propagating waves, and nearshore model prediction error is often dominated by uncertainty in offshore boundary conditions. Offshore islands and shoals, and coastline curvature, create complex sheltering patterns over the 250km span of southern California (SC) shoreline. Here, regional wave model skill in SC was compared for different offshore boundary conditions created using offshore buoy observations and global wave model hindcasts (National Oceanographic and Atmospheric Administration Wave Watch 3, WW3). Spectral ray-tracing methods were used to transform incident offshore swell (0.04-0.09Hz) energy at high directional resolution (1-deg). Model skill is assessed for predictions (wave height, direction, and alongshore radiation stress) at 16 nearshore buoy sites between 2000 and 2009. Model skill using buoy-derived boundary conditions is higher than with WW3-derived boundary conditions. Buoy-driven nearshore model results are similar with various assumptions about the true offshore directional distribution (maximum entropy, Bayesian direct, and 2nd derivative smoothness). Two methods combining offshore buoy observations with WW3 predictions in the offshore boundary condition did not improve nearshore skill above buoy-only methods. A case example at Oceanside harbor shows strong sensitivity of alongshore sediment transport predictions to different offshore boundary conditions. Despite this uncertainty in alongshore transport magnitude, alongshore gradients in transport (e.g. the location of model accretion and erosion zones) are determined by the local bathymetry, and are similar for all predictions.

Verifying mapping, monitoring and modeling of fine sediment pollution sources in West Maui, Hawai'i, USA

NASA Astrophysics Data System (ADS)

Cerovski-Darriau, C.; Stock, J. D.

2017-12-01

Coral reef ecosystems, and the fishing and tourism industries they support, depend on clean waters. Fine sediment pollution from nearshore watersheds threatens these enterprises in West Maui, Hawai'i. To effectively mitigate sediment pollution, we first have to know where the sediment is coming from, and how fast it erodes. In West Maui, we know that nearshore sediment plumes originate from erosion of fine sand- to silt-sized air fall deposits where they are exposed by grazing, agriculture, or other disturbances. We identified and located these sediment sources by mapping watershed geomorphological processes using field traverses, historic air photos, and modern orthophotos. We estimated bank lowering rates using erosion pins, and other surface erosion rates were extrapolated from data collected elsewhere on the Hawaiian Islands. These measurements and mapping led to a reconnaissance sediment budget which showed that annual loads are dominated by bank erosion of legacy terraces. Field observations during small storms confirm that nearshore sediment plumes are sourced from bank erosion of in-stream, legacy agricultural deposits. To further verify this sediment budget, we used geochemical fingerprinting to uniquely identify each potential source (e.g. stream banks, agricultural fields, roads, other human modified soils, and hillslopes) from the Wahikuli watershed (10 km2) and analyzed the fine fraction using ICP-MS for elemental geochemistry. We propose to apply this the fingerprinting results to nearshore suspended sediment samples taken during storms to identify the proportion of sediment coming from each source. By combining traditional geomorphic mapping, monitoring and geochemistry, we hope to provide a powerful tool to verify the primary source of sediment reaching the nearshore.

Bacterial communities in Great Barrier Reef calcareous sediments: Contrasting 16S rDNA libraries from nearshore and outer shelf reefs

NASA Astrophysics Data System (ADS)

Uthicke, S.; McGuire, K.

2007-03-01

Bacterial communities in eight 16S rDNA clone libraries from calcareous sediments were investigated to provide an assessment of the bacterial diversity on sediments of the Great Barrier Reef (GBR) and to investigate differences due to decreased water quality. Sample effort was spread across two locations on each of four coral reefs, with two reefs located nearshore and two reefs on the outer shelf to allow robust statistical comparison of nearshore reefs (subjected to enhanced runoff) and outer shelf reefs (pristine conditions). Out of 221 non-chimeric sequences, 189 (85.5%) were unique and only one sequence occurred in more than one library. Rarefaction analyses and coverage calculations indicated that only a small fraction of the diversity was sampled. Cluster analyses and comparison to published sequences indicated that sequences retrieved belonged to the α, γ and δ subdivision of the Proteobacteria (6.8, 29.4 and 13.6% of the total, respectively), Cytophaga-Flavobacteria-Bacteroidetes (CFB) group (20.4%), Cyanobacteria (5.4%), Planctomycetaceae (7.7%), Verrucomicrobiaceae (6.8%), Acidobacteriaceae (2.7%). Analysis of Similarity (ANOSIM, based on grouping all retrieved sequences into 9 phylogenetic groups) indicated that subtle differences do exist in the community composition between nearshore and outer shelf reefs. Similarity percentage analysis (SIMPER) indicated that Acidobacteriaceae and Cyanobacteriaceae were the main contributors to the dissimilarity. A significant difference between bacteria on nearshore and outer shelf reefs also existed on the molecular level ( FST = 0.008, p = 0.007 for all samples, 0.006, p = 0.022 when repeated sequences within libraries were removed). Thus, bacterial communities on carbonate sediments investigated were highly diverse and differences in community composition may provide important leads for the search for indicator species or communities for water quality differences.

Contrasting Impact of Future CO2 Emission Scenarios on the Extent of CaCO3 Mineral Undersaturation in the Humboldt Current System

NASA Astrophysics Data System (ADS)

Franco, A. C.; Gruber, N.; Frölicher, T. L.; Kropuenske Artman, L.

2018-03-01

The eastern boundary upwelling systems are among those regions that are most vulnerable to an ocean acidification-induced transition toward undersaturated conditions with respect to mineral CaCO3, but no assessment exists yet for the Humboldt Current System. Here we use a high-resolution (˜7.5 km) regional ocean model to investigate past and future changes in ocean pH and CaCO3 saturation state in this system. We find that within the next few decades, the nearshore waters off Peru are projected to become corrosive year round with regard to aragonite, the more soluble form of CaCO3. The volume of aragonite undersaturated water off Peru will continue to increase in the future irrespective of the amount of CO2 emitted to the atmosphere. In contrast, the development of the saturation state with regard to calcite, a less soluble form of carbonate, depends strongly on the scenario followed. By 2050, calcite undersaturation appears in the nearshore waters off Peru occasionally, but by 2090 in a high-emission scenario (RCP8.5), ˜60% of the water in the euphotic zone will become permanently calcite undersaturated. Most of this calcite undersaturation off Peru can likely be avoided if a low emission scenario (RCP2.6) consistent with the Paris Agreement is followed. The progression of ocean acidification off Chile follows a similar pattern, except that the saturation states are overall higher. But also here, calcite undersaturated waters will become common in the subsurface waters under the RCP8.5 scenario by the end of this century, while this can be avoided under the RCP2.6 scenario.

Shell architecture: a novel proxy for paleotemperature reconstructions?

NASA Astrophysics Data System (ADS)

Milano, Stefania; Nehrke, Gernot; Wanamaker, Alan D., Jr.; Witbaard, Rob; Schöne, Bernd R.

2017-04-01

Mollusk shells are unique high-resolution paleoenvironmental archives. Their geochemical properties, such as oxygen isotope composition (δ18Oshell) and element-to-calcium ratios, are routinely used to estimate past environmental conditions. However, the existing proxies have certain drawbacks that can affect paleoreconstruction robustness. For instance, the estimation of water temperature of brackish and near-shore environments can be biased by the interdependency of δ18Oshell from multiple environmental variables (water temperature and δ18Owater). Likely, the environmental signature can be masked by physiological processes responsible for the incorporation of trace elements into the shell. The present study evaluated the use of shell structural properties as alternative environmental proxies. The sensitivity of shell architecture at µm and nm-scale to the environment was tested. In particular, the relationship between water temperature and microstructure formation was investigated. To enable the detection of potential structural changes, the shells of the marine bivalves Cerastoderma edule and Arctica islandica were analyzed with Scanning Electron Microscopy (SEM), nanoindentation and Confocal Raman Microscopy (CRM). These techniques allow a quantitative approach to the microstructural analysis. Our results show that water temperature induces a clear response in shell microstructure. A significant alteration in the morphometric characteristics and crystallographic orientation of the structural units was observed. Our pilot study suggests that shell architecture records environmental information and it has potential to be used as novel temperature proxy in near-shore and open ocean habitats.

Use of Spatial Sampling and Microbial Source-Tracking Tools for Understanding Fecal Contamination at Two Lake Erie Beaches

USGS Publications Warehouse

Francy, Donna S.; Bertke, Erin E.; Finnegan, Dennis P.; Kephart, Christopher M.; Sheets, Rodney A.; Rhoades, John; Stumpe, Lester

2006-01-01

Source-tracking tools were used to identify potential sources of fecal contamination at two Lake Erie bathing beaches: an urban beach (Edgewater in Cleveland, Ohio) and a beach in a small city (Lakeshore in Ashtabula, Ohio). These tools included identifying spatial patterns of Escherichia coli (E. coli) concentrations in each area, determining weather patterns that caused elevated E. coli, and applying microbial source tracking (MST) techniques to specific sites. Three MST methods were used during this study: multiple antibiotic resistance (MAR) indexing of E. coli isolates and the presence of human-specific genetic markers within two types of bacteria, the genus Bacteroides and the species Enterococcus faecium. At Edgewater, sampling for E. coli was done during 2003-05 at bathing-area sites, at nearshore lake sites, and in shallow ground water in foreshore and backshore areas. Spatial sampling at nearshore lake sites showed that fecal contamination was most likely of local origin; E. coli concentrations near the mouths of rivers and outfalls remote to the beach were elevated (greater than 235 colony-forming units per 100 milliliters (CFU/100 mL)) but decreased along transport pathways to the beach. In addition, E. coli concentrations were generally highest in bathing-area samples collected at 1- and 2-foot water depths, midrange at 3-foot depths, and lowest in nearshore lake samples typically collected 150 feet from the shoreline. Elevated E. coli concentrations at bathing-area sites were generally associated with increased wave heights and rainfall, but not always. E. coli concentrations were often elevated in shallow ground-water samples, especially in samples collected less than 10 feet from the edge of water (near foreshore area). The interaction of shallow ground water and waves may be a mechanism of E. coli storage and accumulation in foreshore sands. Infiltration of bird feces through sand with surface water from rainfall and high waves may be concentrating E. coli in shallow ground water in foreshore and backshore sands. At Lakeshore, sampling for E. coli was done at bathing-area, nearshore lake, and parking-lot sites during 2004-05. Low concentrations of E. coli at nearshore lake sites furthest from the shoreline indicated that fecal contamination was most likely of local origin. High concentrations of E. coli in water and bed sediments at several nearshore lake sites showed that contamination was emanating from several points along the shoreline during wet and dry weather, including the boat ramp, an area near the pond drainage, and parking-lot sediments. Physical evidence confirmed that runoff from the parking lot leads to degradation of water quality at the beach. MST samples were collected to help interpret spatial findings and determine whether sources of fecal contamination were from wastewater or bird feces and if a human-specific marker was present. MAR indices were useful in distinguishing between bird feces and wastewater sources because they were about 10 times higher in the latter. The results from MAR indices agreed with results from the two human-specific markers in some but not all of the samples tested. Bacteroides and enterococci human-specific markers were found on one day at Edgewater and two days at Lakeshore. On three days at Edgewater and two days at Lakeshore, the MAR index indicated a mixed source, but neither marker was found in bathing-water samples; this may be because bacterial indicator concentrations were too low to detect a marker. Multiple tools are needed to help identify sources of fecal contamination at coastal beaches. Spatial sampling identified patterns in E. coli concentrations and yielded information on the physical pathways of contamination. MST methods provided information on whether the source was likely of human or nonhuman origin only; however, MST did not provide information on the pathways of contamination.

The first US National Coastal Condition Assessment survey in the Great Lakes: Development of the GIS frame and exploration of spatial variation in nearshore water quality results

EPA Science Inventory

A comprehensive approach to assess conditions in the Great Lakes nearshore zone has been lacking for decades. We had the opportunity to conduct a pilot survey in Lake Erie (45 sites) in summer 2009 and to develop a full survey across the 5 lakes (~400 sites) as part of the US N...

Methodology for prediction of rip currents using a three-dimensional numerical, coupled, wave current model

USGS Publications Warehouse

Voulgaris, George; Kumar, Nirnimesh; Warner, John C.; Leatherman, Stephen; Fletemeyer, John

2011-01-01

Rip current currents constitute one of the most common hazards in the nearshore that threaten the lives of the unaware public that makes recreational use of the coastal zone. Society responds to this danger through a number of measures that include: (a) the deployment of trained lifeguards; (b) public education related to the hidden hazards of the nearshore; and (c) establishment of warning systems.

Optical Imaging of the Nearshore

DTIC Science & Technology

2010-09-30

understand the dynamics of the nearshore system that we measure. APPROACH We exploit a number of approaches in our work. Our observational...resolution, time domain data of optical radiance at a number of focus research sites. Recently, we have collaborated with Dr. Merrick Haller of OSU to...not display a currently valid OMB control number . 1. REPORT DATE 2011 2. REPORT TYPE N/A 3. DATES COVERED - 4. TITLE AND SUBTITLE Optical

Thirty Years of Nearshore Research

NASA Astrophysics Data System (ADS)

Stanton, T. P.

2006-12-01

An assessment of Ed Thornton's contributions to nearshore wave, current and morphology research on the eve of his retirement reveals his ability to identify important unresolved processes, and to participate in multidisciplinary research programs that address those issues. While doing this, he has consistently helped foster the new generations of field scientists both by supervising strong masters and PhD students from around the world, and through working with successful postdoctoral students, many of whom will present talks in this session. This presentation will summarize the major field programs that he has very actively participated in starting from my first field work with him as a colleague/helper in the NSTS Blacks Beach and Santa Barbara experiments. In reviewing these experiments it is interesting to see the evolution of our understanding of the surf zone from simplified 2D wave breaking processes to the 3D wave/current/sediment transport problems seen in morphologically controlled rip currents, both through our ability to measure these processes, but also in the sophistication of numerical models of the nearshore. This review also shows how the consistent and well directed basic research funding from the Coastal Geosciences program at ONR has greatly benefited the Navy and the community at large. I know the nearshore community looks forward to continued associations with him during his very active retirement.

An exploratory investigation of the landscape-lake interface: Land cover controls over consumer N and C isotopic composition in Lake Michigan rivermouths

USGS Publications Warehouse

Larson, James H.; Richardson, William B.; Vallazza, Jonathan M.; Nelson, J. C.

2012-01-01

Rivermouth ecosystems are areas where tributary waters mix with lentic near-shore waters and provide habitat for many Laurentian Great Lakes fish and wildlife species. Rivermouths are the interface between terrestrial activities that influence rivers and the ecologically important nearshore. Stable isotopes of nitrogen (N) and carbon (C) in consumers were measured from a range of rivermouths systems to address two questions: 1) What is the effect of rivermouth ecosystems and land cover on the isotopic composition of N available to rivermouth consumers? 2) Are rivermouth consumers composed of lake-like or river-like C? For question 1, data suggest that strong relationships between watershed agriculture and consumer N are weakened or eliminated at the rivermouth, in favor of stronger relationships between consumer N and depositional areas that may favor denitrification. For question 2, despite apparently large riverine inputs, consumers only occasionally appear river-like. More often consumers seem to incorporate large amounts of C from either the nearshore or primary production within the rivermouth itself. Rivermouths appear to be active C and N processing environments, thus necessitating their explicit incorporation into models estimating nearshore loading and possibly contributing to their importance to Great Lakes biota.

The contribution of nearshore fish aggregating devices (FADs) to food security and livelihoods in Solomon Islands.

PubMed

Albert, Joelle A; Beare, Doug; Schwarz, Anne-Maree; Albert, Simon; Warren, Regon; Teri, James; Siota, Faye; Andrew, Neil L

2014-01-01

Fish aggregating devices, or FADs, are used widely in developing countries to concentrate pelagic fish, making them easier to catch. Nearshore FADs anchored close to the coast allow access for rural communities, but despite their popularity among policy makers, there is a dearth of empirical analysis of their contributions to the supply of fish and to fisheries management. In this paper we demonstrate that nearshore FADs increased the supply of fish to four communities in Solomon Islands. Estimated total annual fish catch ranged from 4300 to 12,000 kg across the study villages, with nearshore FADs contributing up to 45% of the catch. While it is clear that FADs increased the supply of fish, FAD catch rates were not consistently higher than other fishing grounds. Villages with limited access to diverse or productive fishing grounds seemingly utilized FADs to better effect. Villagers believed FADs increased household income and nutrition, as well as providing a source of fish for community events. FADs were also perceived to increase intra-household conflict and reduce fishers' participation in community activities. FADs need to be placed within a broader rural development context and treated as another component in the diversified livelihoods of rural people; as with other livelihood options they bring trade-offs and risks.

Variability In Long-Wave Runup as a Function of Nearshore Bathymetric Features

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

Dunkin, Lauren McNeill

Beaches and barrier islands are vulnerable to extreme storm events, such as hurricanes, that can cause severe erosion and overwash to the system. Having dunes and a wide beach in front of coastal infrastructure can provide protection during a storm, but the influence that nearshore bathymetric features have in protecting the beach and barrier island system is not completely understood. The spatial variation in nearshore features, such as sand bars and beach cusps, can alter nearshore hydrodynamics, including wave setup and runup. The influence of bathymetric features on long-wave runup can be used in evaluating the vulnerability of coastal regionsmore » to erosion and dune overtopping, evaluating the changing morphology, and implementing plans to protect infrastructure. In this thesis, long-wave runup variation due to changing bathymetric features as determined with the numerical model XBeach is quantified (eXtreme Beach behavior model). Wave heights are analyzed to determine the energy through the surfzone. XBeach assumes that coastal erosion at the land-sea interface is dominated by bound long-wave processes. Several hydrodynamic conditions are used to force the numerical model. The XBeach simulation results suggest that bathymetric irregularity induces significant changes in the extreme long-wave runup at the beach and the energy indicator through the surfzone.« less

[Characteristics of particle size structure of plankton community in turbidity zone of near-shore waters, Liaoning Province of Northeast China].

PubMed

Song, Lun; Wang, Nian-bin; Song, Yong-Gang; Li, Nan

2013-04-01

Estuary and nearshore waters have complicated environment, where plankton community has a frequent feedback regulation and a very unstable particle size structure. In this paper, an investigation was made on the particle size structure of plankton in the turbidity zone of nearshore and port area waters in Liaoning Province of Northeast China. In the waters with high concentration inorganic nitrogen, phytoplankton biomass was mainly of small particle sizes, with the equivalent sphere diameter (ESD) being primarily 20-100 micro m, while in low nutrient waters, the phytoplankton biomass was mainly of larger size particles, with the ESD>100 micro m, indicating that the phytoplankton feedback regulation caused the phytoplankton community to be comprised of small sized organisms as part of the biological responses to high concentration suspended solids, which reduced the individual number of larger organisms such as Coscinodiscus. sp. and other species, and in turn, directly affected the fisheries resources, including a variety of fish and shrimp larvae fed on phytoplankton. A normalized biomass size spectrum with the characteristics of nearshore shallow aquatic oceanic ecosystems exhibiting eutrophication was constructed. The spectrum slope indicated that the plankton community biomass would gradually increase in size. The feasibility of using dinoflagellates and cladocerans as the bio-indicators for eutrophication was discussed.

The Contribution of Nearshore Fish Aggregating Devices (FADs) to Food Security and Livelihoods in Solomon Islands

PubMed Central

Albert, Joelle A.; Beare, Doug; Schwarz, Anne-Maree; Albert, Simon; Warren, Regon; Teri, James; Siota, Faye; Andrew, Neil L.

2014-01-01

Fish aggregating devices, or FADs, are used widely in developing countries to concentrate pelagic fish, making them easier to catch. Nearshore FADs anchored close to the coast allow access for rural communities, but despite their popularity among policy makers, there is a dearth of empirical analysis of their contributions to the supply of fish and to fisheries management. In this paper we demonstrate that nearshore FADs increased the supply of fish to four communities in Solomon Islands. Estimated total annual fish catch ranged from 4300 to 12 000 kg across the study villages, with nearshore FADs contributing up to 45% of the catch. While it is clear that FADs increased the supply of fish, FAD catch rates were not consistently higher than other fishing grounds. Villages with limited access to diverse or productive fishing grounds seemingly utilized FADs to better effect. Villagers believed FADs increased household income and nutrition, as well as providing a source of fish for community events. FADs were also perceived to increase intra-household conflict and reduce fishers' participation in community activities. FADs need to be placed within a broader rural development context and treated as another component in the diversified livelihoods of rural people; as with other livelihood options they bring trade-offs and risks. PMID:25513808

Volume and surface area size distribution, water mass and model fitting of GCE/CASE/WATOX marine aerosols

NASA Astrophysics Data System (ADS)

Kim, Y.; Sievering, H.; Boatman, J.

1990-06-01

As a part of the Global Change Expedition/Coordinated Air-Sea Experiment/Western Atlantic Ocean Experiment (GCE/CASE/WATOX), size distributions of marine aerosols were measured at two altitudes of about 2750 and 150 m above sea level (asl) over the size range 0.1 ˜ 32 μm. Lognormal fitting was applied to the corrected aerosol size spectra to determine the volume and surface area size distributions of the CASE-WATOX marine aerosols. Each aerosol size distribution was fitted with three lognormal distributions representing fine-, large-, and giant-particle modes. Water volume fraction and dry particle size of each aerosol size distribution were also calculated using empirical formulas for particle size as a function of relative humidity and particle type. Because of the increased influence from anthropogenic sources in the continental United States, higher aerosol volume concentrations were observed in the fine-particle mode near-shore off the east coast; 2.11 and 3.63 μm3 cm-3 for free troposphere (FT) and marine boundary layer (MBL), compared with the open-sea Bermuda area values; 0.13 and 0.74 μm3 cm-3 for FT and MBL. The large-particle mode exhibits the least variations in volume distributions between the east coast and open-sea Bermuda area, having a volume geometric median diameter (VGMD) between 1.4 and 1.6 μm and a geometric standard deviation between 1.57 and 1.68. For the giant-particle mode, larger VGMD and volume concentrations were observed for marine aerosols nearshore off the east coast than in the open-sea Bermuda area because of higher relative humidity and higher surface wind speed conditions. Wet VGMD and aerosol water volume concentrations at 15 m asl ship level were determined by extrapolating from those obtained by analysis of the CASE-WATOX aircraft aerosol data. Abundance of aerosol water in the MBL serves as an important pathway for heterogeneous conversion of SO2 in sea salt aerosol particles.

Early Permian post-glacial bivalve faunas of the Itararé Group, Paraná Basin, Brazil: Paleoecology and biocorrelations with South American intraplate basins

NASA Astrophysics Data System (ADS)

Neves, Jacqueline Peixoto; Anelli, Luiz Eduardo; Simões, Marcello Guimarães

2014-07-01

The uppermost portion of the Taciba Formation, Itararé Group, Paraná Basin, Brazil, records a succession of depositional environments tied to the demise of late Paleozoic glaciation. In the study area, Teixeira Soares county, state of Paraná, the unit is dominated by massive to laminated diamictites with inclusions of sandstones and other coarse-grained lithotypes, representing re-sedimented material in proximal areas. These are succeeded by fine to medium-grained sandstones with tabular cross-stratification and pectinid-rich shell pavements, interpreted as nearshore deposits. Above this, laminated and intensely bioturbated siltstones with closed articulated bivalve shells are recorded, probably deposited in inner shelf settings. Fine to very fine sandstones/siltstones with hummocky cross-stratification and intercalated mudstones, including infaunal in situ shells, are interpreted as stacked storm deposits, generated in distal shoreface environments. These are succeeded by fossil-poor, massive to laminated siltstones/mudstones or gray shales (=Passinho shale) that are inferred to be outer shelf deposits, generated in organic-rich, oxygen-deficient muddy bottoms. In this sedimentary succession dropstones or ice-rafted debris are missing and locally the Passinho shale marks the maximum flooding surface of the Itararé succession. These are capped by the fluvio-deltaic deposits of the Rio Bonito Formation (Sakmarian-Artinskian). Six facies-controlled, bivalve-dominated assemblages are recognized, representing faunal associations that thrived in aerobic to extreme dysaerobic bottoms along a nearshore-offshore trend. Within these assemblages, nineteen bivalve species (three of them new) were recorded and described in detail. The presence of Myonia argentinensis (Harrington), Atomodesma (Aphanaia) orbirugata (Harrington) and Heteropecten paranaensis Neves et al. suggests correlation with bivalve assemblages of the Eurydesma-bearing Bonete Formation, Pillahuincó Group, Sauce Grande-Colorado Basin (Buenos Aires Province), Argentina, indicating a possible Asselian age for this diverse post-glacial bivalve fauna. Despite that, typical members of the icehouse-style Eurydesma-Trigonotreta biota (stricto sensu) have not yet been found in the studied bivalve assemblages.

Measuring Bathymetry, Runup, and Beach Volume Change during Storms: New Methodology Quantifies Substantial Changes in Cross-Shore Sediment Flux

NASA Astrophysics Data System (ADS)

Brodie, K. L.; McNinch, J. E.

2009-12-01

Accurate predictions of beach change during storms are contingent upon a correct understanding of wave-driven sediment exchange between the beach and nearshore during high energy conditions. Conventional storm data sets use “pre” (often weeks to months prior) and “post” (often many days after the storm in calm conditions) collections of beach topography and nearshore bathymetry to characterize the effects of the storm. These data have led to a common theory for wave-driven event response of the nearshore system, wherein bars and shorelines are smoothed and straightened by strong alongshore currents into two-dimensional, linear forms. Post-storm, the shoreline accretes, bars migrate onshore, and three-dimensional shapes begin to build as low-energy swell returns. Unfortunately, these approaches have left us with a knowledge gap of the extent and timing of erosion and accretion during storms, arguably the most important information both for scientists trying to model storm damage or inundation, and homeowners trying to manage their properties. This work presents the first spatially extensive (10 km alongshore) and temporally high-resolution (dt = 12 hours) quantitative data set of beach volume and nearshore bathymetry evolution during a Nor’easter on North Carolina’s Outer Banks. During the Nor’easter, significant wave height peaked at 3.4 m, and was greater than 2 m for 37 hours, as measured by the Duck FRF 8 m array. Data were collected using CLARIS: Coastal Lidar and Radar Imaging System, a mobile system that couples simultaneous observations of beach topography from a Riegl laser scanner and nearshore bathymetry (out to ~1 km offshore) from X-Band radar-derived celerity measurements (BASIR). The merging of foreshore lidar elevations with 6-min averages of radar-derived swash runup also enables mapping of maximum-runup elevations alongshore during the surveys. Results show that during the storm, neither the shoreline nor nearshore bathymetry returned to a linear system, as shoreline megacusps/embayments and nearshore shore-oblique bars/troughs both persisted and remained aligned throughout the storm. Analysis of beach volume change above the MHW line showed that all of the erosion occurred during the first 24 hours of the storm, as the 8-m significant wave height grew from 1 to 3.5 m at the peak of the storm and wave period increased from 6 to 14 s. In the 12 hours immediately following the storm peak, as long-period swell fell only 1 m, at least 50% of the eroded upper-beach volume returned along the entire study site, with 100% and greater returning along half the study site. This erosion and accretion would be completely unobserved using traditional pre- and post-storm data sets. Maximum runup varied by as much as 2 m alongshore, showing a weak positive correlation with foreshore slope. Maximum runup is the sum of regional tide and surge (pressure and wind-driven) water levels as well as localized wave-driven setup and swash, and thus may have complex alongshore variations where irregular nearshore bathymetry significantly influences shoreline wave-setup.

Carolinas Coastal Change Processes Project data report for nearshore observations at Cape Hatteras, North Carolina

USGS Publications Warehouse

Armstrong, Brandy N.; Warner, John C.; Voulgaris, George; List, Jeffrey H.; Thieler, Robert; Martini, Marinna A.; Montgomery, Ellyn T.; McNinch, Jesse E.; Book, Jeffrey W.; Haas, Kevin

2013-01-01

An oceanographic field study conducted in February 2010 investigated processes that control nearshore flow and sediment transport dynamics at Cape Hatteras, North Carolina. This report describes the project background, field program, instrumentation setup, and locations of the sensor deployments. The data collected, and supporting meteorological and streamflow observations, are presented as time-series plots for data visualization. Additionally, the data are available as part of this report.

Strategic Placement of Mixed Sediment in the Form of a Nearshore Berm along Fort Myers Beach, Florida

DTIC Science & Technology

2017-03-28

reusable and sustainable placement site. 6. The nearshore berm will allow increased shore protection from large waves breaking and attenuating on the berm...maintenance in 1986, 1996, and 2001 (Florida Department of Environmental Protection 2009). In the past, as part of regional sediment management, sediment...Environmental Protection 2009). Figure 1. Study area and survey line locations. Sanibel Island (to the northwest of Estero Island) shelters Fort

Superduck Marine Meteorological Experiment Data Summary: Mean Values and Turbulence Parameters.

DTIC Science & Technology

1988-08-01

number) This report summarizes the Mean values and turbulence parameters Of Meteorological measurements made during an experiment at Duck, NC, during...Sept-Oct 1986. The measure- ments wore made to Calculate wind stress in the nearshore area. Wind stress is a primary forcing function for nearshore waves...measure. Only in recent years has technology made it possible to accurately measure its fluctuations. The krypton hygrometer is a recent development

Nearshore Measurements From a Small UAV.

NASA Astrophysics Data System (ADS)

Holman, R. A.; Brodie, K. L.; Spore, N.

2016-02-01

Traditional measurements of nearshore hydrodynamics and evolving bathymetry are expensive and dangerous and must be frequently repeated to track the rapid changes of typical ocean beaches. However, extensive research into remote sensing methods using cameras or radars mounted on fixed towers has resulted in increasingly mature algorithms for estimating bathymetry, currents and wave characteristics. This naturally raises questions about how easily and effectively these algorithms can be applied to optical data from low-cost, easily-available UAV platforms. This paper will address the characteristics and quality of data taken from a small, low-cost UAV, the DJI Phantom. In particular, we will study the stability of imagery from a vehicle `parked' at 300 feet altitude, methods to stabilize remaining wander, and the quality of nearshore bathymetry estimates from the resulting image time series, computed using the cBathy algorithm. Estimates will be compared to ground truth surveys collected at the Field Research Facility at Duck, NC.

Controls of multi-modal wave conditions in a complex coastal setting

USGS Publications Warehouse

Hegermiller, Christie; Rueda, Ana C.; Erikson, Li H.; Barnard, Patrick L.; Antolinez, J.A.A.; Mendez, Fernando J.

2017-01-01

Coastal hazards emerge from the combined effect of wave conditions and sea level anomalies associated with storms or low-frequency atmosphere-ocean oscillations. Rigorous characterization of wave climate is limited by the availability of spectral wave observations, the computational cost of dynamical simulations, and the ability to link wave-generating atmospheric patterns with coastal conditions. We present a hybrid statistical-dynamical approach to simulating nearshore wave climate in complex coastal settings, demonstrated in the Southern California Bight, where waves arriving from distant, disparate locations are refracted over complex bathymetry and shadowed by offshore islands. Contributions of wave families and large-scale atmospheric drivers to nearshore wave energy flux are analyzed. Results highlight the variability of influences controlling wave conditions along neighboring coastlines. The universal method demonstrated here can be applied to complex coastal settings worldwide, facilitating analysis of the effects of climate change on nearshore wave climate.

Controls of Multimodal Wave Conditions in a Complex Coastal Setting

NASA Astrophysics Data System (ADS)

Hegermiller, C. A.; Rueda, A.; Erikson, L. H.; Barnard, P. L.; Antolinez, J. A. A.; Mendez, F. J.

2017-12-01

Coastal hazards emerge from the combined effect of wave conditions and sea level anomalies associated with storms or low-frequency atmosphere-ocean oscillations. Rigorous characterization of wave climate is limited by the availability of spectral wave observations, the computational cost of dynamical simulations, and the ability to link wave-generating atmospheric patterns with coastal conditions. We present a hybrid statistical-dynamical approach to simulating nearshore wave climate in complex coastal settings, demonstrated in the Southern California Bight, where waves arriving from distant, disparate locations are refracted over complex bathymetry and shadowed by offshore islands. Contributions of wave families and large-scale atmospheric drivers to nearshore wave energy flux are analyzed. Results highlight the variability of influences controlling wave conditions along neighboring coastlines. The universal method demonstrated here can be applied to complex coastal settings worldwide, facilitating analysis of the effects of climate change on nearshore wave climate.

Status and trends in the Lake Superior fish community, 2014

USGS Publications Warehouse

Vinson, Mark; Evrard, Lori M.; Gorman, Owen T.; Yule, Daniel

2015-01-01

In 2014, the Lake Superior fish community was sampled with daytime bottom trawls at 73 nearshore and 30 offshore stations. Spring and summer water temperatures were the coldest measured for the period of records for the surveys. In the nearshore zone, a total of 15,372 individuals from 28 species or morphotypes were collected. Nearshore lakewide mean biomass was 6.9 kg/ha, which was higher than that observed in the past few years, but below the long-term average of 9.2 kg/ha. In the offshore zone, a total 12,462 individuals from 11 species were collected lakewide. Offshore lakewide mean biomass was 6.6 kg/ha. The mean of the three previous years was 8.6 kg/ha. We collected larval Coregonus in surface trawls at 94 locations and estimated a lakewide average density of 577 fish/ha with a total lakewide population estimate of 14.2 billion (standard error + 30 million).

Hazardous geology zoning and influence factorsin the near-shore shallow strata and seabed surfaceof the modern Yellow River Delta, China

NASA Astrophysics Data System (ADS)

Li, P.

2016-12-01

In this study, on the basis of 3,200 km shallow stratigraphic section and sidescan sonar data of the coastal area of the Yellow River Delta, we delineated and interpreted a total of seven types of typical hazardous geologies, including the hazardous geology in the shallow strata (buried ancient channel and strata disturbance) and hazardous geology in the seabed surface strata (pit, erosive residual body, sand patch, sand wave and scour channel). We selected eight parameters representing the development scale of the hazardous geology as the zoning indexes, including the number of hazardous geology types, pit depth, height of erosive residual body, length of scour channel, area of sand patch, length of sand wave, width of the buried ancient channel and depth of strata disturbance, and implemented the grid processing of the research area to calculate the arithmetic sum of the zoning indexes of each unit grid one by one. We then adopted the clustering analysis method to divide the near-shore waters of the Yellow River Delta into five hazardous geology areas, namely the serious erosion disaster area controlled by Diaokou lobe waves, hazardous geology area of multi-disasters under the combined action of the Shenxiangou lobe river wave flow, accumulation type hazardous geology area controlled by the current estuary river, hazardous geology area of single disaster in the deep water area and potential hazardous geology area of the Chengdao Oilfield. All four of the main factors affecting the development of hazardous geology, namely the diffusion and movement of sediment flux of the Yellow River water entering the sea, seabed stability, bottom sediment type and distribution, as well as the marine hydrodynamic characteristics, show significant regional differentiation characteristics and laws. These characteristics and laws are consistent with the above-mentioned zoning results, in which the distribution, scale and genetic mechanism of hazardous geology are considered comprehensively. This indicates that the hazardous geology zoning based on the cluster analysis is a new attempt in research regarding the hazardous geology zoning of the near-shore waters of the modern Yellow River Delta and that this type of zoning has a high level of reasonability.

Contribution of sea ice microbial production to Antarctic benthic communities is driven by sea ice dynamics and composition of functional guilds.

PubMed

Wing, Stephen R; Leichter, James J; Wing, Lucy C; Stokes, Dale; Genovese, Sal J; McMullin, Rebecca M; Shatova, Olya A

2018-04-28

Organic matter produced by the sea ice microbial community (SIMCo) is an important link between sea ice dynamics and secondary production in near-shore food webs of Antarctica. Sea ice conditions in McMurdo Sound were quantified from time series of MODIS satellite images for Sept. 1 through Feb. 28 of 2007-2015. A predictable sea ice persistence gradient along the length of the Sound and evidence for a distinct change in sea ice dynamics in 2011 were observed. We used stable isotope analysis (δ 13 C and δ 15 N) of SIMCo, suspended particulate organic matter (SPOM) and shallow water (10-20 m) macroinvertebrates to reveal patterns in trophic structure of, and incorporation of organic matter from SIMCo into, benthic communities at eight sites distributed along the sea ice persistence gradient. Mass-balance analysis revealed distinct trophic architecture among communities and large fluxes of SIMCo into the near-shore food web, with the estimates ranging from 2 to 84% of organic matter derived from SIMCo for individual species. Analysis of patterns in density, and biomass of macroinvertebrate communities among sites allowed us to model net incorporation of organic matter from SIMCo, in terms of biomass per unit area (g/m 2 ), into benthic communities. Here, organic matter derived from SIMCo supported 39 to 71 per cent of total biomass. Furthermore, for six species, we observed declines in contribution of SIMCo between years with persistent sea ice (2008-2009) and years with extensive sea ice breakout (2012-2015). Our data demonstrate the vital role of SIMCo in ecosystem function in Antarctica and strong linkages between sea ice dynamics and near-shore secondary productivity. These results have important implications for our understanding of how benthic communities will respond to changes in sea ice dynamics associated with climate change and highlight the important role of shallow water macroinvertebrate communities as sentinels of change for the Antarctic marine ecosystem. © 2018 John Wiley & Sons Ltd.

Glacial Lake Lind, Wisconsin and Minnesota

USGS Publications Warehouse

Johnson, M.D.; Addis, K.L.; Ferber, L.R.; Hemstad, C.B.; Meyer, G.N.; Komai, L.T.

1999-01-01

Glacial Lake Lind developed in the pre-late Wisconsinan St. Croix River valley, Minnesota and Wisconsin, and lasted more than 1000 yr during the retreat of the Superior lobe at the end of the Wisconsinan glaciation. Lake Lind sediment consists primarily of red varved silt and clay, but also includes mud-flow deposits, nearshore silt (penecontemporaneously deformed in places), nearshore rippled sand, and deltaic sand. Lake Lind varved red clay is not part of glacial Lake Grantsburg, as suggested by earlier authors, because the red varves are separated from overlying glacial Lake Grantsburg silt and clay by a unit of deltaic and fluvial sand. Furthermore, varve correlations indicate that the base of the red varves is younger to the north, showing that the basin expanded as the Superior lobe retreated and was not a lake basin dammed to the southwest by the advancing Grantsburg sublobe. Varve correlations indicate that the Superior lobe retreated at a rate of about 200 m/yr. Uniform winter-clay thickness throughout most of the varve couplets suggests thermal stratification in the lake with clay trapped in the epilimnion; some clay would exit the lake at the outlet prior to winter freeze. Zones of thicker winter-clay layers, in places associated with mud-flow layers, indicate outlet incision, lake-level fall, and shoreline erosion and resuspension of lake clay. The most likely outlet for glacial Lake Lind was in the southwest part of the lake near the present site of Minneapolis, Minnesota. Nearshore sediment indicates that the lake level of glacial Lake Lind was around 280 m. The elevation of the base of the Lake Lind sediments indicates water depth was 20 to 55 m. Evidence in the southern part of the lake basin suggests that the Superior lobe readvanced at least once during the early stages of glacial Lake Lind. Lake Lind ended not by drainage but by being filled in by prograding deltas and outwash plains composed of sand derived from the retreating Superior lobe. It was upon this fluvial surface that the Grantsburg sublobe advanced, depositing till and forming glacial Lake Grantsburg.

Spectral Characterization of the Wave Energy Resource for Puerto Rico (PR) and the United States Virgin Islands (USVI)

NASA Astrophysics Data System (ADS)

Garcia, C. G.; Canals, M.; Irizarry, A. A.

2016-02-01

Nowadays a significant amount of wave energy assessments have taken place due to the development of the ocean energy markets worldwide. Energy contained in surface gravity waves is scattered along frequency components that can be described using wave spectra. Correspondingly, characterization and quantification of harvestable wave energy is inherently dictated by the nature of the two-dimensional wave spectrum. The present study uses spectral wave data from the operational SWAN-based CariCOOS Nearshore Wave Model to evaluate the capture efficiency of multiple wave energy converters (WEC). This study revolves around accurately estimating available wave energy as a function of varying spectral distributions, effectively providing a detailed insight concerning local wave conditions for PR and USVI and the resulting available-energy to generated-power ratio. Results in particular, provide a comprehensive characterization of three years' worth of SWAN-based datasets by outlining where higher concentrations of wave energy are localized in the spectrum. Subsequently, the aforementioned datasets were processed to quantify the amount of energy incident on two proposed sites located in PR and USVI. Results were largely influenced by local trade wind activity, which drive predominant sea states, and the amount of North-Atlantic swells that propagate towards the region. Each wave event was numerically analyzed in the frequency domain to evaluate the capacity of a WEC to perform under different spectral distribution scenarios, allowing for a correlation between electrical power output and spectral energy distribution to be established.

The Coastal Dynamics of Heterogeneous Sedimentary Environments: Numerical Modeling of Nearshore Hydrodynamics and Sediment Transport

DTIC Science & Technology

2010-05-10

supplied boundary data for Hurricane Katrina (Keen, Furukawa et al. 2006; Keen, Slingerland et al. 2010). The numerical models discussed in this report...explicitly. NCOM can be nested to a coarse-grid model to supply boundary conditions at the open boundary of the domain. NCOM has been validated at global...circulation study of Mississippi Sound (Keen 2002), which supplied steady currents for the nearshore erosion problem discussed in this report

Recolonization of the intertidal and shallow subtidal community following the 2008 eruption of Alaska’s Kasatochi Volcano

USGS Publications Warehouse

Jewett, S.C.; Drew, Gary S.

2014-01-01

The intertidal and nearshore benthic communities of Kasatochi Island are described following a catastrophic volcanic eruption in 2008. Prior to the eruption, the island was surrounded by a dense bed of canopy-forming dragon kelp Eualaria fistulosa which supported a productive nearshore community. The eruption extended the coastline of the island approximately 400 m offshore to roughly the 20 m isobath. One year following the eruption a reconnaissance survey found the intertidal zone devoid of life. Subtidally, the canopy kelp, as well as limited understory algal species and associated benthic fauna on the hard substratum, were buried by debris from the eruption. The resulting substrate was comprised almost entirely of medium and coarse sands with a depauperate benthic community. Comparisons of habitat and biological communities with other nearby Aleutian Islands and the Icelandic submarine volcanic eruption of Surtsey confirm dramatic reductions in flora and fauna consistent with the initial stages of recovery from a large-scale disturbance event. Four and five years following the eruption brief visits revealed dramatic intertidal and subtidal recolonization of the flora and fauna in some areas. Signs of nesting and fledging of young pigeon guillemots Cepphus columba suggest that the recovery of the nearshore biota may have begun affecting higher trophic levels. Recolonization or lack thereof was tied to bathymetric changes from coastal and nearshore erosion over the study period.

Spatial Distribution and Effects of Sewage in Coastal Hawaiian Waters

NASA Astrophysics Data System (ADS)

Abaya, L.; Wiegner, T. N.; Colbert, S.; Lindsey, K.; Beets, J.

2016-02-01

Sewage pollution is a worldwide threat to marine ecosystems and human health through the release of pathogens and nutrients into nearshore waters. Goals of this study were to document hydrological connections between cesspools and nearshore waters, detect the presence of sewage through biological and chemical tracers, and determine the spatial extent of sewage offshore. Puakō, located on Hawaíi Island, was the focus of this study as most homes have cesspools. Fluorescein dye injected into cesspools was detected at the shoreline in as little as three days. Elevated δ 15N signatures in macroalgae and high Enterococcus counts further confirmed presence of sewage in nearshore waters. Offshore sampling revealed significant differences among distances from shore for fecal indicator bacteria and δ 15N signatures in macroalgae. Results indicated distance from shore and stations are important factors of variability. Additionally, nutrient concentrations and macroalgal cover were higher in areas with high groundwater discharge. Surprisingly, δ15N macroalgal signatures and Enterococcus were not correlated with salinity. These results suggest that possibly the location of cesspools, subsurface geology, and/or nearshore circulation may affect sewage transport to the coastline and offshore. Spatial analysis techniques helped visualize potential hot spots of sewage pollution using δ15N macroalgal and Enterococcus data. The combination of tools used here to document sewage pollution presence may be useful for communities facing similar environmental problems.

Recolonization of the intertidal and shallow subtidal community following the 2008 eruption of Alaska's Kasatochi Volcano

NASA Astrophysics Data System (ADS)

Jewett, S. C.; Drew, G. S.

2014-03-01

The intertidal and nearshore benthic communities of Kasatochi Island are described following a catastrophic volcanic eruption in 2008. Prior to the eruption, the island was surrounded by a dense bed of canopy-forming dragon kelp Eualaria fistulosa which supported a productive nearshore community. The eruption extended the coastline of the island approximately 400 m offshore to roughly the 20 m isobath. One year following the eruption a reconnaissance survey found the intertidal zone devoid of life. Subtidally, the canopy kelp, as well as limited understory algal species and associated benthic fauna on the hard substratum, were buried by debris from the eruption. The resulting substrate was comprised almost entirely of medium and coarse sands with a depauperate benthic community. Comparisons of habitat and biological communities with other nearby Aleutian Islands and the Icelandic submarine volcanic eruption of Surtsey confirm dramatic reductions in flora and fauna consistent with the initial stages of recovery from a large-scale disturbance event. Four and five years following the eruption brief visits revealed dramatic intertidal and subtidal recolonization of the flora and fauna in some areas. Signs of nesting and fledging of young pigeon guillemots Cepphus columba suggest that the recovery of the nearshore biota may have begun affecting higher trophic levels. Recolonization or lack thereof was tied to bathymetric changes from coastal and nearshore erosion over the study period.

Use of nearshore and estuarine areas by gray whales (Eschrichtius robustus) in the eastern Bering Sea

USGS Publications Warehouse

Gill, Robert E.; Hall, John D.

1983-01-01

During spring aerial surveys of the coast of the southeastern Bering Sea significant numbers of gray whales were seen in nearshore waters along the north side of the Alaska Peninsula. Many (50-80%) of these animals were observed surfacing with mud trails or lying on their sides, characteristics both associated with feeding. A migration route close to shore (within 1-2 km) was used until whales neared Egegik Bay, where they began to head west 5-8 km offshore, across northern Bristol Bay. Smaller numbers of gray whales were present throughout summer in nearshore waters and estuaries along the north side of the Alaska Peninsula. At Nelson Lagoon gray whales normally used the lagoon in spring, were absent during early summer, returned in mid-summer, and then were present until late November when they departed for the wintering grounds. Gray whales were present in the lagoon most often during periods of peak tidal flow; those that appeared to be feeding were oriented into the current. Three behaviors that appeared to be associated with feeding were observed: side-feeding from a stationary position within shallow waters of lagoon channels, diving within the lagoon and in nearshore waters, and elliptical side-feeding in the surf zone along the outer coast. Large crustaceans of the genus Crangon were available to and probably eaten by gray whales at Nelson Lagoon.

Operational prediction of rip currents using numerical model and nearshore bathymetry from video images

NASA Astrophysics Data System (ADS)

Sembiring, L.; Van Ormondt, M.; Van Dongeren, A. R.; Roelvink, J. A.

2017-07-01

Rip currents are one of the most dangerous coastal hazards for swimmers. In order to minimize the risk, a coastal operational-process based-model system can be utilized in order to provide forecast of nearshore waves and currents that may endanger beach goers. In this paper, an operational model for rip current prediction by utilizing nearshore bathymetry obtained from video image technique is demonstrated. For the nearshore scale model, XBeach1 is used with which tidal currents, wave induced currents (including the effect of the wave groups) can be simulated simultaneously. Up-to-date bathymetry will be obtained using video images technique, cBathy 2. The system will be tested for the Egmond aan Zee beach, located in the northern part of the Dutch coastline. This paper will test the applicability of bathymetry obtained from video technique to be used as input for the numerical modelling system by comparing simulation results using surveyed bathymetry and model results using video bathymetry. Results show that the video technique is able to produce bathymetry converging towards the ground truth observations. This bathymetry validation will be followed by an example of operational forecasting type of simulation on predicting rip currents. Rip currents flow fields simulated over measured and modeled bathymetries are compared in order to assess the performance of the proposed forecast system.

High Temporal Resolution Characterization of the Carbonate Chemistry and the Relative Influence of Community Metabolic Processes on Controlling Coral Reef Dynamics at La Parguera, Puerto Rico

NASA Astrophysics Data System (ADS)

Melendez, M.; Salisbury, J.; Gledhill, D. K.; Musielewicz, S.; Morell, J. M.; Manzello, D.

2016-02-01

Diverse metabolic processes in conjunction with thermodynamic, physical and benthic related processes modulate seawater carbonate chemistry in near-shore environments. Such processes operate at different time scales. In the open ocean, dynamics and trends in carbonate chemistry are reasonably well constrained and often characterized based on TA-salinity and pCO2-temperature relationships. However, in near-shore environments benthic and coastal processes can convolute these relationships and careful direct measurement of the carbonate system (e.g. through alkalinity and dissolved inorganic carbon) is needed. To this end, we characterized seasonal and inter-annual carbonate dynamics from 2009 to 2014 at the Class III fixed climate station of La Parguera Marine Reserve, Puerto Rico. This high-temporal resolution chemical monitoring at Enrique reef facilitated an examination of what local processes might prove dominant, and how changes in community-scale metabolic performance might alter the dynamics of the carbonate system within the near-shore reef waters. Changes in pCO2,sw at Enrique reef are strongly associated with both community inorganic and organic carbon production processes. Enrique reef is a persistent source of CO2 to the atmosphere (1.8 mmol CO2 m-2 d-1, SE = 0.04) with at maximum peak during the summer and fall seasons. During the same time, carbonate mineral saturation state are generally lower along the fore-reef relative to offshore waters and dominantly controlled by short-term pCO2,sw dynamics primarily driven by benthic community organic matter productivity, temperature and salinity seasonal changes. At this time, high temperatures coincide with intense local rainfall and the influx of the low-salinity Amazon and Orinoco River plumes into the eastern Caribbean. One benefit of such measurements is that they provide data for a more accurate determination of TA-salinity relationships for our region and site-specific algorithms for first order derivations of other carbonate system parameters.

Inter-nesting movements and habitat-use of adult female Kemp’s ridley turtles in the Gulf of Mexico

PubMed Central

Hart, Kristen M.; Fujisaki, Ikuko; Bucklin, David; Iverson, Autumn R.; Rubio, Cynthia; Backof, Thomas F.; Burchfield, Patrick M.; de Jesus Gonzales Diaz Miron, Raul; Dutton, Peter H.; Frey, Amy; Peña, Jaime; Gomez Gamez, Daniel; Martinez, Hector J.; Ortiz, Jaime

2017-01-01

Species vulnerability is increased when individuals congregate in restricted areas for breeding; yet, breeding habitats are not well defined for many marine species. Identification and quantification of these breeding habitats are essential to effective conservation. Satellite telemetry and switching state-space modeling (SSM) were used to define inter-nesting habitat of endangered Kemp’s ridley turtles (Lepidochelys kempii) in the Gulf of Mexico. Turtles were outfitted with satellite transmitters after nesting at Padre Island National Seashore, Texas, USA, from 1998 through 2013 (n = 60); Rancho Nuevo, Tamaulipas, Mexico, during 2010 and 2011 (n = 11); and Tecolutla, Veracruz, Mexico, during 2012 and 2013 (n = 11). These sites span the range of nearly all nesting by this species. Inter-nesting habitat lies in a narrow band of nearshore western Gulf of Mexico waters in the USA and Mexico, with mean water depth of 14 to 19 m within a mean distance to shore of 6 to 11 km as estimated by 50% kernel density estimate, α-Hull, and minimum convex polygon methodologies. Turtles tracked during the inter-nesting period moved, on average, 17.5 km/day and a mean total distance of 398 km. Mean home ranges occupied were 725 to 2948 km2. Our results indicate that these nearshore western Gulf waters represent critical inter-nesting habitat for this species, where threats such as shrimp trawling and oil and gas platforms also occur. Up to half of all adult female Kemp’s ridleys occupy this habitat for weeks to months during each nesting season. Because inter-nesting habitat for this species is concentrated in nearshore waters of the western Gulf of Mexico in both Mexico and the USA, international collaboration is needed to protect this essential habitat and the turtles occurring within it. PMID:28319178

Paleo-environmental interpretation of Paleocene Sepultura Formation in type locality, Mesa La sepultura, Baja California, Mexico

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

Arzate-Hernandez, L.; Tellezduarte, M.

1988-03-01

The Sepultura Formation in its type locality consists of two major lithostratigraphic units. The basal A unit overlies the Cretaceous Rosario Formation. It consists predominantly of fine-grained, poorly consolidated sandstones; some conglomerates; and thin beds of well-consolidated lenticular fossiliferous sandstones, which show some cyclic sedimentation. The poorly consolidated sandstones contain glauconitic layers; abundant shark teeth, benthic forams, and ostracods; and sparse mollusks, brachiopods, and Ophiomorpha-like trace fossils. These faunas indicate deposition in nearshore shallow waters. The interbedded consolidated lenticular sandstones probably indicate storm-induced deposition below wave base. This mechanism is assumed to be responsible for the high concentration of fossilsmore » consisting predominantly of unworn molluscan shells, scaphopods, echinoid spines, corals, and forams. In places, the elongated shells of Turritella pachecoensis show a preferential orientation to the southwest. At the top of the unit, a poorly fossiliferous red conglomerate indicates deltaic conditions. Overlying the conglomerate is unit B which shows a change in the sedimentary environment. It consists of a calcareous shallowing upward sequence of nodular to massive algal limestone with caliche at top. The microfossils of this unit show glauconitization in places, and consist, in addition to algal fragments, of forams, microscopic mollusks, and some ostracods and calcispherules from shallow waters (less than 30 m deep).« less

Southwest Washington littoral drift restoration—Beach and nearshore morphological monitoring

USGS Publications Warehouse

Stevens, Andrew W.; Gelfenbaum, Guy; Ruggiero, Peter; Kaminsky, George M.

2012-01-01

A morphological monitoring program has documented the placement and initial dispersal of beach nourishment material (280,000 m3) placed between the Mouth of the Columbia River (MCR) North Jetty and North Head, at the southern end of the Long Beach Peninsula in southwestern Washington State. A total of 21 topographic surveys and 8 nearshore bathymetric surveys were performed between July 11, 2010, and November 4, 2011. During placement, southerly alongshore transport resulted in movement of nourishment material to the south towards the MCR North Jetty. Moderate wave conditions (significant wave height around 4 m) following the completion of the nourishment resulted in cross-shore sediment transport, with most of the nourishment material transported into the nearshore bars. The nourishment acted as a buffer to the more severe erosion, including dune overtopping and retreat, that was observed at the northern end of the study area throughout the winter. One year after placement of the nourishment, onshore transport and beach recovery were most pronounced within the permit area and to the south toward the MCR North Jetty. This suggests that there is some long-term benefit of the nourishment for reducing erosion rates locally, although the enhanced recovery also could be due to natural gradients in alongshore transport causing net movement of the sediment from north to south. Measurements made during the morphological monitoring program documented the seasonal movement and decay of nearshore sand bars. Low-energy conditions in late summer resulted in onshore bar migration early in the monitoring program. Moderate wave conditions in the autumn resulted in offshore movement of the middle bar and continued onshore migration of the outer bar. High-energy wave conditions early in the winter resulted in strong cross-shore transport and creation of a 3-bar system along portions of the coast. More southerly wave events occurred later in the winter and early spring and coincided with the complete loss of the outer bar and net loss of sediment from the study area. These data suggest that bar decay may be an important mechanism for exporting sediment from Benson Beach north to the Long Beach Peninsula. The measurements presented in this report represent one component of a broader monitoring program designed to track the movement of nourishment material on the beach and shoreface at this location, including continuous video monitoring (Argus), in situu measurements of hydrodynamics, and a physical tracer experiment. Field data from the monitoring program will be used to test numerical models of hydrodynamics and sediment transport and to improve the capability of numerical models to support regional sediment management.

Influence of basin- and local-scale environmental conditions on nearshore production in the northeast Pacific Ocean

USGS Publications Warehouse

von Biela, Vanessa R.; Zimmerman, Christian E.; Kruse, Gordon H.; Mueter, Franz J.; Black, Bryan A.; Douglas, David C.; Bodkin, James L.

2016-01-01

Nearshore marine habitats are productive and vulnerable owing to their connections to pelagic and terrestrial landscapes. To understand how ocean basin- and local-scale conditions may influence nearshore species, we developed an annual index of nearshore production (spanning the period 1972–2010) from growth increments recorded in otoliths of representative pelagic-feeding (Black Rockfish Sebastes melanops) and benthic-feeding (Kelp Greenling Hexagrammos decagrammus) nearshore-resident fishes at nine sites in the California Current and Alaska Coastal Current systems. We explored the influence of basin- and local-scale conditions across all seasons at lags of up to 2 years to represent changes in prey quantity (1- or 2-year time lags) and quality (within-year relationships). Relationships linking fish growth to basin-scale (Pacific Decadal Oscillation, North Pacific Gyre Oscillation, and multivariate El Niño–Southern Oscillation index) and local-scale (sea surface temperature, sea surface height anomalies, upwelling index, photosynthetically active radiation, and freshwater discharge) environmental conditions varied by species and current system. Growth of Black Rockfish increased with cool basin-scale conditions in the California Current and warm local-scale conditions in the Alaska Coastal Current, consistent with existing hypotheses linking climate to pelagic production on continental shelves in the respective regions. Relationships for Kelp Greenlings in the California Current were complex, with faster growth related to within-year warm conditions and lagged-year cool conditions. These opposing, lag-dependent relationships may reflect differences in conditions that promote quantity versus quality of benthic invertebrate prey in the California Current. Thus, we hypothesize that benthic production is maximized by alternating cool and warm years, as benthic invertebrate recruitment is food limited during warm years while growth is temperature limited by cool years in the California Current. On the other hand, Kelp Greenlings grew faster during and subsequent to warm conditions at basin and local scales in the Alaska Coastal Current.

Nearshore circulation on a sea breeze dominated beach during intense wind events

NASA Astrophysics Data System (ADS)

Torres-Freyermuth, Alec; Puleo, Jack A.; DiCosmo, Nick; Allende-Arandía, Ma. Eugenia; Chardón-Maldonado, Patricia; López, José; Figueroa-Espinoza, Bernardo; de Alegria-Arzaburu, Amaia Ruiz; Figlus, Jens; Roberts Briggs, Tiffany M.; de la Roza, Jacobo; Candela, Julio

2017-12-01

A field experiment was conducted on the northern Yucatan coast from April 1 to April 12, 2014 to investigate the role of intense wind events on coastal circulation from the inner shelf to the swash zone. The study area is characterized by a micro-tidal environment, low-energy wave conditions, and a wide and shallow continental shelf. Furthermore, easterly trade winds, local breezes, and synoptic-scale events, associated with the passage of cold-fronts known as Nortes, are ubiquitous in this region. Currents were measured concurrently at different cross-shore locations during both local and synoptic-scale intense wind events to investigate the influence of different forcing mechanisms (i.e., large-scale currents, winds, tides, and waves) on the nearshore circulation. Field observations revealed that nearshore circulation across the shelf is predominantly alongshore-directed (westward) during intense winds. However, the mechanisms responsible for driving instantaneous spatial and temporal current variability depend on the weather conditions and the across-shelf location. During local strong sea breeze events (W > 10 m s-1 from the NE) occurring during spring tide, westward circulation is controlled by the tides, wind, and waves at the inner-shelf, shallow waters, and inside the surf/swash zone, respectively. The nearshore circulation is relaxed during intense land breeze events (W ≈ 9 m s-1 from the SE) associated with the low atmospheric pressure system that preceded a Norte event. During the Norte event (Wmax≈ 15 m s-1 from the NNW), westward circulation dominated outside the surf zone and was correlated to the Yucatan Current, whereas wave breaking forces eastward currents inside the surf/swash zone. The latter finding implies the existence of large alongshore velocity shear at the offshore edge of the surf zone during the Norte event, which enhances mixing between the surf zone and the inner shelf. These findings suggest that both sea breezes and Nortes play an important role in sediment and pollutant transport along/across the nearshore of the Yucatan shelf.

Water temperatures in select nearshore environments of the Colorado River in Grand Canyon, Arizona, during the Low Steady Summer Flow experiment of 2000

USGS Publications Warehouse

Vernieu, William S.; Anderson, Craig R.

2013-01-01

Water releases from Glen Canyon Dam, Arizona, are the primary determinant of streamflow, sediment transport, water quality, and aquatic and riparian habitat availability in the Colorado River downstream of the dam in Grand Canyon. The presence and operation of the dam have transformed the seasonally warm Colorado River into a consistently cold river because of hypolimnetic, or deep-water, releases from the penstock withdrawal structures on the dam. These releases have substantially altered the thermal regime of the downstream riverine environment. This, in turn, has affected the biota of the river corridor, particularly native and nonnative fish communities and the aquatic food web. In the spring and summer of 2000, a Low Steady Summer Flow experiment was conducted by the U.S. Geological Survey and the Bureau of Reclamation to evaluate the effects of the experimental flow on physical and biological resources of the Colorado River ecosystem downstream from Glen Canyon Dam to Lake Mead on the Arizona-Nevada border. This report describes the water temperatures collected during the experimental flow from 14 nearshore sites in the river corridor in Grand Canyon to assess the effects of steady releases on the thermal dynamics of nearshore environments. These nearshore areas are characterized by low-velocity flows with some degree of isolation from the higher velocity flows in the main channel and are hypothesized to be important rearing environments for young native fish. Water-temperature measurements were made at 14 sites, ranging from backwater to open-channel environments. Warming during daylight hours, relative to main-channel temperatures, was measured at all sites in relation to the amount of isolation from the main-channel current. Boat traffic, amount of direct solar radiation, and degree of isolation from the main-channel current appear to be the primary factors affecting the differential warming of the nearshore environment.

Nitrogen Isotopic Study of Benthic Macroalgae and Seawater in Biscayne Bay, Florida

NASA Astrophysics Data System (ADS)

Drayer, C. L.; Lamb, K. A.; Swart, P. K.; Altabet, M. A.; Anderson, W. T.; Bellmund, S.

2006-12-01

Biscayne Bay, Florida is a complex coastal environment with many possible natural and anthropogenic sources of nitrogen. Such sources include precipitation, N fixation, nutrient regeneration/recycling, landfill soil leaching, groundwater and agricultural runoff, septic tank leakage, and treated waste water effluent. In order to understand the relative importance of these various inputs, benthic macroalgae, seagrasses, and seawater samples were collected from Biscayne Bay transecting from canals through nearshore bay to offshore reef sites Macroalgae was identified by species, decarbonated, and analyzed for δ15N and δ13C. The mean δ15N and δ13C for the algal tissue were +5.4 (±0.3‰) and -15.1 (±0.1‰), respectively. Measured nearshore algal samples differed greatly from offshore samples and had a high δ15N value of +12.0 (±0.1‰) and a mean of +8.6 (±3.0‰), in comparison to offshore samples that averaged +4.7 (±2.5‰). Despite the variation in δ15N, the δ13C values for both nearshore and offshore samples fell within the accepted parameters for algal communities. Seawater was analyzed for δ15N in DIN (dissolved inorganic nitrogen) and DON (dissolved organic nitrogen) through the cadmium reduction method (Mcllvin and Altabet, 2005). The mean δ15N for the DIN was +4.5 (±3.9‰) and the DON was +5.8 (±3.3‰). Canal DON δ15N values contained the heaviest measured values at ~+18‰, while nearshore and offshore DON values were lighter, 4.9 (±1.6‰). DIN values were more spatially variable with canal and nearshore sites ranging from ~+10‰ through ~-4.5‰. This study will continue over the next two years to examine possible temporal C and N isotope variations and will expand to include a larger geographic region focusing on areas with high nutrient levels and harmful algae blooms (HABs).

The Effect of Regional Tectonics on Faults in Bonaire and the Bonaire Basin: A Seismic Reflection Study

NASA Astrophysics Data System (ADS)

Brandl, C.; Reece, R.; Bayer, J.; Bales, M. K.

2016-12-01

Bonaire is located on the Bonaire microplate between the Caribbean and South American plates, and is part of the Netherlands Leeward Antilles as well as the ABC Islands along with Aruba and Curacao. As the major tectonic plates move they stress the microplate, which causes deformation as faulting. This study utilizes legacy seismic reflection data combined with a recent nearshore survey to study tectonic deformation in the basins surrounding Bonaire. Our legacy data covers a large portion of the ABC Islands; one dataset is a 1981 multichannel seismic (MCS) WesternGeco survey and the other is a 1971 USGS survey that we converted from print to SEGY. The modern dataset (2013) is a high-resolution MCS survey acquired off the western coast of Bonaire. We will use the legacy datasets to validate previous interpretations in the nearshore environment and extend these interpretations to the deepwater basins. Faults influenced by regional tectonics are more evident in deepwater basins because of their lateral continuity, and offset of thick sedimentary strata. A recent study of nearshore Bonaire utilizing the high-resolution seismic dataset interpreted several NE-SW dipping normal faults, which may correspond to regional extension. However, the influence is not clear, perhaps due to a lack of data or the nearshore nature of the dataset. Analysis of the legacy datasets show several areas in the surrounding basins with faults dipping NE-SW. Further analysis may reinforce observations made in the nearshore environment. Studying the tectonics of Bonaire can provide insight about the evolution of the region and help better define the effect of regional tectonic forces on the microplate. This study also shows the benefit of legacy seismic datasets that are publically available but stored as print or film in conjunction with modern data. They can provide value to a modern study by expanding the scope of available data as well as increasing the number of questions a study can address.

Latitudinal discontinuity in thermal conditions along the nearshore of central-northern Chile.

PubMed

Tapia, Fabian J; Largier, John L; Castillo, Manuel; Wieters, Evie A; Navarrete, Sergio A

2014-01-01

Over the past decade, evidence of abrupt latitudinal changes in the dynamics, structure and genetic variability of intertidal and subtidal benthic communities along central-northern Chile has been found consistently at 30-32°S. Changes in the advective and thermal environment in nearshore waters have been inferred from ecological patterns, since analyses of in situ physical data have thus far been missing. Here we analyze a unique set of shoreline temperature data, gathered over 4-10 years at 15 sites between 28-35°S, and combine it with satellite-derived winds and sea surface temperatures to investigate the latitudinal transition in nearshore oceanographic conditions suggested by recent ecological studies. Our results show a marked transition in thermal conditions at 30-31°S, superimposed on a broad latitudinal trend, and small-scale structures associated with cape-and-bay topography. The seasonal cycle dominated temperature variability throughout the region, but its relative importance decreased abruptly south of 30-31°S, as variability at synoptic and intra-seasonal scales became more important. The response of shoreline temperatures to meridional wind stress also changed abruptly at the transition, leading to a sharp drop in the occurrence of low-temperature waters at northern sites, and a concurrent decrease in corticated algal biomass. Together, these results suggest a limitation of nitrate availability in nearshore waters north of the transition. The localized alongshore change results from the interaction of latitudinal trends (e.g., wind stress, surface warming, inertial period) with a major headland-bay system (Punta Lengua de Vaca at 30.25°S), which juxtaposes a southern stretch of coast characterized by upwelling with a northern stretch of coast characterized by warm surface waters and stratification. This transition likely generates a number of latitude-dependent controls on ecological processes in the nearshore that can explain species-specific effects, and add strength to the suggestion of an oceanography-driven, major spatial transition in coastal communities at 30-31°S.

First quantification of subtidal community structure at Tristan da Cunha Islands in the remote South Atlantic: from kelp forests to the deep sea

PubMed Central

Hamilton, Scott L.; Davis, Kathryn; Thompson, Christopher D. H.; Turchik, Alan; Jenkinson, Ryan; Simpson, Doug; Sala, Enric

2018-01-01

Tristan da Cunha Islands, an archipelago of four rocky volcanic islands situated in the South Atlantic Ocean and part of the United Kingdom Overseas Territories (UKOTs), present a rare example of a relatively unimpacted temperate marine ecosystem. We conducted the first quantitative surveys of nearshore kelp forests, offshore pelagic waters and deep sea habitats. Kelp forests had very low biodiversity and species richness, but high biomass and abundance of those species present. Spatial variation in assemblage structure for both nearshore fish and invertebrates/algae was greatest between the three northern islands and the southern island of Gough, where sea temperatures were on average 3-4o colder. Despite a lobster fishery that provides the bulk of the income to the Tristan islands, lobster abundance and biomass are comparable to or greater than many Marine Protected Areas in other parts of the world. Pelagic camera surveys documented a rich biodiversity offshore, including large numbers of juvenile blue sharks, Prionace glauca. Species richness and abundance in the deep sea is positively related to hard rocky substrate and biogenic habitats such as sea pens, crinoids, whip corals, and gorgonians were present at 40% of the deep camera deployments. We observed distinct differences in the deep fish community above and below ~750 m depth. Concurrent oceanographic sampling showed a discontinuity in temperature and salinity at this depth. While currently healthy, Tristan’s marine ecosystem is not without potential threats: shipping traffic leading to wrecks and species introductions, pressure to increase fishing effort beyond sustainable levels and the impacts of climate change all could potentially increase in the coming years. The United Kingdom has committed to protection of marine environments across the UKOTs, including Tristan da Cunha and these results can be used to inform future management decisions as well as provide a baseline against which future monitoring can be based. PMID:29596484

First quantification of subtidal community structure at Tristan da Cunha Islands in the remote South Atlantic: from kelp forests to the deep sea.

PubMed

Caselle, Jennifer E; Hamilton, Scott L; Davis, Kathryn; Thompson, Christopher D H; Turchik, Alan; Jenkinson, Ryan; Simpson, Doug; Sala, Enric

2018-01-01

Tristan da Cunha Islands, an archipelago of four rocky volcanic islands situated in the South Atlantic Ocean and part of the United Kingdom Overseas Territories (UKOTs), present a rare example of a relatively unimpacted temperate marine ecosystem. We conducted the first quantitative surveys of nearshore kelp forests, offshore pelagic waters and deep sea habitats. Kelp forests had very low biodiversity and species richness, but high biomass and abundance of those species present. Spatial variation in assemblage structure for both nearshore fish and invertebrates/algae was greatest between the three northern islands and the southern island of Gough, where sea temperatures were on average 3-4o colder. Despite a lobster fishery that provides the bulk of the income to the Tristan islands, lobster abundance and biomass are comparable to or greater than many Marine Protected Areas in other parts of the world. Pelagic camera surveys documented a rich biodiversity offshore, including large numbers of juvenile blue sharks, Prionace glauca. Species richness and abundance in the deep sea is positively related to hard rocky substrate and biogenic habitats such as sea pens, crinoids, whip corals, and gorgonians were present at 40% of the deep camera deployments. We observed distinct differences in the deep fish community above and below ~750 m depth. Concurrent oceanographic sampling showed a discontinuity in temperature and salinity at this depth. While currently healthy, Tristan's marine ecosystem is not without potential threats: shipping traffic leading to wrecks and species introductions, pressure to increase fishing effort beyond sustainable levels and the impacts of climate change all could potentially increase in the coming years. The United Kingdom has committed to protection of marine environments across the UKOTs, including Tristan da Cunha and these results can be used to inform future management decisions as well as provide a baseline against which future monitoring can be based.

Research on numerical method for multiple pollution source discharge and optimal reduction program

NASA Astrophysics Data System (ADS)

Li, Mingchang; Dai, Mingxin; Zhou, Bin; Zou, Bin

2018-03-01

In this paper, the optimal method for reduction program is proposed by the nonlinear optimal algorithms named that genetic algorithm. The four main rivers in Jiangsu province, China are selected for reducing the environmental pollution in nearshore district. Dissolved inorganic nitrogen (DIN) is studied as the only pollutant. The environmental status and standard in the nearshore district is used to reduce the discharge of multiple river pollutant. The research results of reduction program are the basis of marine environmental management.

Radar Remote Sensing of Waves and Currents in the Nearshore Zone

DTIC Science & Technology

2006-01-01

and application of novel microwave, acoustic, and optical remote sensing techniques. The objectives of this effort are to determine the extent to which...Doppler radar techniques are useful for nearshore remote sensing applications. Of particular interest are estimates of surf zone location and extent...surface currents, waves, and bathymetry. To date, optical (video) techniques have been the primary remote sensing technology used for these applications. A key advantage of the radar is its all weather day-night operability.

Social-ecological network analysis of scale mismatches in estuary watershed restoration.

PubMed

Sayles, Jesse S; Baggio, Jacopo A

2017-03-07

Resource management boundaries seldom align with environmental systems, which can lead to social and ecological problems. Mapping and analyzing how resource management organizations in different areas collaborate can provide vital information to help overcome such misalignment. Few quantitative approaches exist, however, to analyze social collaborations alongside environmental patterns, especially among local and regional organizations (i.e., in multilevel governance settings). This paper develops and applies such an approach using social-ecological network analysis (SENA), which considers relationships among and between social and ecological units. The framework and methods are shown using an estuary restoration case from Puget Sound, United States. Collaboration patterns and quality are analyzed among local and regional organizations working in hydrologically connected areas. These patterns are correlated with restoration practitioners' assessments of the productivity of their collaborations to inform network theories for natural resource governance. The SENA is also combined with existing ecological data to jointly consider social and ecological restoration concerns. Results show potentially problematic areas in nearshore environments, where collaboration networks measured by density (percentage of possible network connections) and productivity are weakest. Many areas also have high centralization (a few nodes hold the network together), making network cohesion dependent on key organizations. Although centralization and productivity are inversely related, no clear relationship between density and productivity is observed. This research can help practitioners to identify where governance capacity needs strengthening and jointly consider social and ecological concerns. It advances SENA by developing a multilevel approach to assess social-ecological (or social-environmental) misalignments, also known as scale mismatches.

Social–ecological network analysis of scale mismatches in estuary watershed restoration

PubMed Central

Sayles, Jesse S.

2017-01-01

Resource management boundaries seldom align with environmental systems, which can lead to social and ecological problems. Mapping and analyzing how resource management organizations in different areas collaborate can provide vital information to help overcome such misalignment. Few quantitative approaches exist, however, to analyze social collaborations alongside environmental patterns, especially among local and regional organizations (i.e., in multilevel governance settings). This paper develops and applies such an approach using social–ecological network analysis (SENA), which considers relationships among and between social and ecological units. The framework and methods are shown using an estuary restoration case from Puget Sound, United States. Collaboration patterns and quality are analyzed among local and regional organizations working in hydrologically connected areas. These patterns are correlated with restoration practitioners’ assessments of the productivity of their collaborations to inform network theories for natural resource governance. The SENA is also combined with existing ecological data to jointly consider social and ecological restoration concerns. Results show potentially problematic areas in nearshore environments, where collaboration networks measured by density (percentage of possible network connections) and productivity are weakest. Many areas also have high centralization (a few nodes hold the network together), making network cohesion dependent on key organizations. Although centralization and productivity are inversely related, no clear relationship between density and productivity is observed. This research can help practitioners to identify where governance capacity needs strengthening and jointly consider social and ecological concerns. It advances SENA by developing a multilevel approach to assess social–ecological (or social–environmental) misalignments, also known as scale mismatches. PMID:28223529

Patterns in Stable Isotope Values of Nitrogen and Carbon in ...

EPA Pesticide Factsheets

Stable isotope measurements of nitrogen and carbon (15N, 13ddC) are often used to characterize estuarine, nearshore, and open ocean ecosystems. Reliable information about the spatial distribution of base-level stable isotope values, often represented by primary producers, is critical to interpreting values in these ecosystems. While base-level isotope data are generally readily available for estuaries, nearshore coastal waters, and the open ocean, the continental shelf is less studied. To address this, and as a first step toward developing a surrogate for base-level isotopic signature in this region, we collected surface and deep water samples from the United States’ eastern continental shelf in the Western Atlantic Ocean, from the Gulf of Maine to Cape Hatteras, periodically between 2000 and 2013. During the study, particulate matter 15dN values ranged from 0.8 to 17.4‰, and 13dC values from −26.4 to −15.6‰over the region. We used spatial autocorrelation analysis and random forest modeling to examine the spatial trends and potential environmental drivers of the stable isotope values. We observed general trends toward lower values for both nitrogen and carbon isotopes at the seaward edge of the shelf. Conversely, higher 15dN and 13dC values were observed on the landward edge of the shelf, in particular in the southern portion of the sampling area. Across all sites, the magnitude of the difference between the 15dN of subsurface and surface particulate m

Population structure of Cladophora-borne Escherichia coli in nearshore water of Lake Michigan.

PubMed

Byappanahalli, Muruleedhara N; Whitman, Richard L; Shively, Dawn A; Ferguson, John; Ishii, Satoshi; Sadowsky, Michael J

2007-08-01

We previously reported that the macrophytic green alga Cladophora harbors high densities (up to 10(6) colony-forming units/g dry weight) of the fecal indicator bacteria, Escherichia coli and enterococci, in shoreline waters of Lake Michigan. However, the population structure and genetic relatedness of Cladophora-borne indicator bacteria remain poorly understood. In this study, 835 E. coli isolates were collected from Cladophora tufts (mats) growing on rocks from a breakwater located within the Indiana Dunes National Lakeshore in northwest Indiana. The horizontal fluorophore enhanced rep-PCR (HFERP) DNA fingerprinting technique was used to determine the genetic relatedness of the isolates to each other and to those in a library of E. coli DNA fingerprints. While the E. coli isolates from Cladophora showed a high degree of genetic relatedness (92% similarity), in most cases, however, the isolates were genetically distinct. The Shannon diversity index for the population was very high (5.39). Both spatial and temporal influences contributed to the genetic diversity. There was a strong association of isolate genotypes by location (79% and 80% for lake- and ditch-side samplings, respectively), and isolates collected from 2002 were distinctly different from those obtained in 2003. Cladophora-borne E. coli isolates represented a unique group, which was distinct from other E. coli isolates in the DNA fingerprint library tested. Taken together, these results indicate that E. coli strains associated with Cladophora may be a recurring source of indicator bacteria to the nearshore beach.

Rapid water quality change in the Elwha River estuary complex during dam removal

USGS Publications Warehouse

Foley, Melissa M.; Duda, Jeffrey J.; Beirne, Matthew M.; Paradis, Rebecca; Ritchie, Andrew; Warrick, Jonathan A.

2015-01-01

Dam removal in the United States is increasing as a result of structural concerns, sedimentation of reservoirs, and declining riverine ecosystem conditions. The removal of the 32 m Elwha and 64 m Glines Canyon dams from the Elwha River in Washington, U.S.A., was the largest dam removal project in North American history. During the 3 yr of dam removal—from September 2011 to August 2014—more than ten million cubic meters of sediment was eroded from the former reservoirs, transported downstream, and deposited throughout the lower river, river delta, and nearshore waters of the Strait of Juan de Fuca. Water quality data collected in the estuary complex at the mouth of the Elwha River document how conditions in the estuary changed as a result of sediment deposition over the 3 yr the dams were removed. Rapid and large-scale changes in estuary conditions—including salinity, depth, and turbidity—occurred 1 yr into the dam removal process. Tidal propagation into the estuary ceased following a large sediment deposition event that began in October 2013, resulting in decreased salinity, and increased depth and turbidity in the estuary complex. These changes have persisted in the system through dam removal, significantly altering the structure and functioning of the Elwha River estuary ecosystem.

Sources and sinks of microplastics in Canadian Lake Ontario nearshore, tributary and beach sediments.

PubMed

Ballent, Anika; Corcoran, Patricia L; Madden, Odile; Helm, Paul A; Longstaffe, Fred J

2016-09-15

Microplastics contamination of Lake Ontario sediments is investigated with the aim of identifying distribution patterns and hotspots in nearshore, tributary and beach depositional environments. Microplastics are concentrated in nearshore sediments in the vicinity of urban and industrial regions. In Humber Bay and Toronto Harbour microplastic concentrations were consistently >500 particles per kg dry sediment. Maximum concentrations of ~28,000 particles per kg dry sediment were determined in Etobicoke Creek. The microplastic particles were primarily fibres and fragments <2mm in size. Both low- and high-density plastics were identified using Raman spectroscopy. We provide a baseline for future monitoring and discuss potential sources of microplastics in terms of how and where to implement preventative measures to reduce the contaminant influx. Although the impacts of microplastics contamination on ecosystem health and functioning is uncertain, understanding, monitoring and preventing further microplastics contamination in Lake Ontario and the other Great Lakes is crucial. Copyright © 2016 Elsevier Ltd. All rights reserved.

On tridimensional rip current modeling

NASA Astrophysics Data System (ADS)

Marchesiello, Patrick; Benshila, Rachid; Almar, Rafael; Uchiyama, Yusuke; McWilliams, James C.; Shchepetkin, Alexander

2015-12-01

Do lateral shear instabilities of nearshore circulation account for a substantial part of Very Low-Frequency (VLF) variability? If yes, it would promote stirring and mixing of coastal waters and surf-shelf exchanges. Another question is whether tridimensional transient processes are important for instability generation. An innovative modeling system with tridimensional wave-current interactions was designed to investigate transient nearshore currents and interactions between nearshore and innershelf circulations. We present here some validation of rip current modeling for the Aquitanian coast of France, using in-situ and remote video sensing. We then proceed to show the benefits of 3D versus 2D (depth-mean flow) modeling of rip currents and their low-frequency variability. It appears that a large part of VLF motions is due to intrinsic variability of the tridimensional flow. 3D models may thus provide a valuable, only marginally more expensive alternative to conventional 2D approaches that miss the vertical flow structure and its nonlinear interaction with the depth-averaged flow.

Human impacts on large benthic foraminifers near a densely populated area of Majuro Atoll, Marshall Islands.

PubMed

Osawa, Yoko; Fujita, Kazuhiko; Umezawa, Yu; Kayanne, Hajime; Ide, Yoichi; Nagaoka, Tatsutoshi; Miyajima, Toshihiro; Yamano, Hiroya

2010-08-01

Human impacts on sand-producing, large benthic foraminifers were investigated on ocean reef flats at the northeast Majuro Atoll, Marshall Islands, along a human population gradient. The densities of dominant foraminifers Calcarina and Amphistegina declined with distance from densely populated islands. Macrophyte composition on ocean reef flats differed between locations near sparsely or densely populated islands. Nutrient concentrations in reef-flat seawater and groundwater were high near or on densely populated islands. delta(15)N values in macroalgal tissues indicated that macroalgae in nearshore lagoons assimilate wastewater-derived nitrogen, whereas those on nearshore ocean reef flats assimilate nitrogen from other sources. These results suggest that increases in the human population result in high nutrient loading in groundwater and possibly into nearshore waters. High nutrient inputs into ambient seawater may have both direct and indirect negative effects on sand-producing foraminifers through habitat changes and/or the collapse of algal symbiosis. Copyright 2010 Elsevier Ltd. All rights reserved.

California coast nearshore processes study. [nearshore currents, sediment transport, estuaries, and river discharge

NASA Technical Reports Server (NTRS)

Pirie, D. M.; Steller, D. D. (Principal Investigator)

1973-01-01

The author has identified the following significant results. Large scale sediment plumes from intermittent streams and rivers form detectable seasonal patterns on ERTS-1 imagery. The ocean current systems, as plotted from three California coast ERTS mosaics, were identified. Offshore patterns of sediment in areas such as the Santa Barbara Channel are traceable. These patterns extend offshore to heretofore unanticipated ranges as shown on the ERTS-1 imagery. Flying spot scanner enhancements of NASA tapes resulted in details of subtle and often invisible (to the eye) nearshore features. The suspended sediments off San Francisco and in Monterey Bay are emphasized in detail. These are areas of extremely changeable offshore sediment transport patterns. Computer generated contouring of radiance levels resulted in maps that can be used in determining surface and nearsurface suspended sediment distribution. Tentative calibrations of ERTS-1 spectral brightness against sediment load have been made using shipboard measurements. Information from the combined enhancement and interpretation techniques is applicable to operational coastal engineering programs.

Toward the Application of the Implicit Particle Filter to Real Data in a Shallow Water Model of the Nearshore Ocean

NASA Astrophysics Data System (ADS)

Miller, R.

2015-12-01

Following the success of the implicit particle filter in twin experiments with a shallow water model of the nearshore environment, the planned next step is application to the intensive Sandy Duck data set, gathered at Duck, NC. Adaptation of the present system to the Sandy Duck data set will require construction and evaluation of error models for both the model and the data, as well as significant modification of the system to allow for the properties of the data set. Successful implementation of the particle filter promises to shed light on the details of the capabilities and limitations of shallow water models of the nearshore ocean relative to more detailed models. Since the shallow water model admits distinct dynamical regimes, reliable parameter estimation will be important. Previous work by other groups give cause for optimism. In this talk I will describe my progress toward implementation of the new system, including problems solved, pitfalls remaining and preliminary results

Trace metal pollution assessment in the surface sediments of nearshore area, off Calicut, southwest coast of India.

PubMed

Srinivas, Reji; Shynu, R; Sreeraj, M K; Ramachandran, K K

2017-07-15

Metal concentrations (Al, Cr, Ni, Cu, Zn, and Pb), grain size, and total organic carbon content in 29 surface sediment samples from the nearshore area off Calicut were analyzed to determine their distribution and pollution status. Surface sediments were dominantly silts with low percentage of clay and sand at nearshore and offshore areas. The mean metal concentrations were in the following order: Cr>Ni>Zn>Pb>Cu. The enrichment factor and geo-accumulation index of metals suggest that the surface sediments were not polluted by Zn and moderately polluted by Cu and Ni. By contrast, Cr and Pb showed significant enrichment levels. Results from a multivariate statistical analysis suggested that the spatial enrichment of these heavy metals was related to sediment type. Thus, the sediment distribution and their metal enrichment were mainly controlled by local hydrodynamic conditions that caused the winnowing of fine-grained sediments. Copyright © 2017. Published by Elsevier Ltd.

Using Stable Isotopes to Assess Connectivity: the Importance ...

EPA Pesticide Factsheets

Estuaries located at the interface of terrestrial and oceanic ecosystems receive nutrients from both ecosystems. Stable isotopes of primary producers and consumers are often used as an indicator of nutrient sources. We assembled natural abundance nitrogen stable isotope (δ15N) data for dissolved inorganic nitrate, green macroalgae, seagrass (Zostera marina) and mussels in the nearshore and in estuaries along the west coast of North America to assess the relative importance of terrestrial and oceanic nutrient sources in these systems. We found a latitudinal gradient in nearshore δ15N of nitrate of -0.2 ‰ per degree latitude from Mexico to British Columbia with more depleted isotope ratio to the north. Primary producers (green macroalgae and Zostera marina) located in the nearshore and the marine dominated portion of Pacific Coast estuaries exhibited a similar latitudinal gradient in δ15N of -0.3 ‰ per degree latitude. This latitudinal gradient is similar to δ15N observed for intertidal mussels (Mytilus californianus), which are known to reflect the isotope ratio of the phytoplankton they feed on. The consistent latitudinal gradient for multiple primary producers and a consumer, and the agreement with the gradient in nearshore δ15N of nitrate, suggests that it is a result of oceanic source waters. On the watershed side, there is a gradient in the δ15N of nitrate with southern California systems receiving nitrate with a δ15N-NO3 of about +12 ‰,

Factors affecting the accumulation of phytoplankton biomass in Irish estuaries and nearshore coastal waters: A conceptual model

NASA Astrophysics Data System (ADS)

O'Boyle, Shane; Wilkes, Robert; McDermott, Georgina; Ní Longphuirt, Sorcha; Murray, Clare

2015-03-01

A multivariate statistical approach was used to investigate the response of phytoplankton in Irish estuaries and nearshore coastal waters to nutrient enrichment and to examine the factors which modulate this response. The analysis suggests that while many estuaries are nutrient-enriched, relatively few display phytoplankton-related symptoms of eutrophication as the response to nutrients is primarily affected by insufficient retention time, in some by inadequate light availability, and only rarely by both factors acting together. Nearshore coastal waters are nitrogen (N) and silica (Si) limited in summer, but in some nearshore waters along the south coast, where N is elevated, phosphorus (P) is potentially limiting. The reduction in P loadings to estuarine waters is likely to lead to an improvement in the eutrophication status of these mainly P-limited waters. The disproportionate reduction in loadings of P compared to N (52% versus 24%, since the early 1990s), and the potential weakening of the estuarine N filter, as eutrophication symptoms lessen, may result in the downstream movement of nitrogen to N-limited coastal waters. These findings support the view that an integrated dual-nutrient reduction strategy is required to address eutrophication along the freshwater-marine continuum. The outcome of the analysis is a conceptual model which is of direct value and use to water managers in determining the relative susceptibility of these waters to nutrient enrichment. This understanding can in turn be used to develop informed programmes of measures which are targeted and ultimately cost effective.

The importance of groundwater discharge to the methane budgets of nearshore and continental shelf waters of the northeastern Gulf of Mexico

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

Bugna, G.C.; Chanton, J.P.; Cable, P.H.

1996-12-01

Methane concentrations in groundwater (wells, sinkholes, and springs) averaged 61 {+-} 9 {mu}M, while concentrations in nearshore and continental shelf waters within the study area averaged 62 {+-} 7 nM and 27 {+-} 5 nM, respectively. We tested the hypothesis that the three orders of magnitude difference between groundwater and seawater concentration would make CH{sub 4} an indicator of submarine groundwater discharge to surficial waters. Methane budgets for nearshore and continental shelf water columns were consistent with the hypothesis that groundwater seepage or seawater recirculation through the seabed is the dominant source of CH{sub 4} relative to benthic diffusive flux,more » riverine flux, and in situ water column production. Seepage/recirculation appears to account for approximately 83-99% of the total CH{sub 4} input into the water column within the study area. Utilizing measured porewater CH{sub 4} concentrations, the calculated amounts of seepage required to support the observed benthic fluxes were comparable to seepage rates measured in the field. Nearshore seepage meter transacts showed a strong and direct correlation between the integrated quantity of groundwater seepage along a shoreline and the inventory of CH{sub 4} in those waters. Our study further showed a similar correlation between {sup 222}Rn (another potential groundwater tracer) and CH{sub 4} in offshore waters supporting the hypothesis of a common benthic source for these constituents. 67 refs., 10 figs., 2 tabs.« less

Forcing and variability of nonstationary rip currents

USGS Publications Warehouse

Long, Joseph W.; H.T. Özkan-Haller,

2016-01-01

Surface wave transformation and the resulting nearshore circulation along a section of coast with strong alongshore bathymetric gradients outside the surf zone are modeled for a consecutive 4 week time period. The modeled hydrodynamics are compared to in situ measurements of waves and currents collected during the Nearshore Canyon Experiment and indicate that for the entire range of observed conditions, the model performance is similar to other studies along this stretch of coast. Strong alongshore wave height gradients generate rip currents that are observed by remote sensing data and predicted qualitatively well by the numerical model. Previous studies at this site have used idealized scenarios to link the rip current locations to undulations in the offshore bathymetry but do not explain the dichotomy between permanent offshore bathymetric features and intermittent rip current development. Model results from the month‐long simulation are used to track the formation and location of rip currents using hourly statistics, and results show that the direction of the incoming wave energy strongly controls whether rip currents form. In particular, most of the offshore wave spectra were bimodal and we find that the ratio of energy contained in each mode dictates rip current development, and the alongshore rip current position is controlled by the incident wave period. Additionally, model simulations performed with and without updating the nearshore morphology yield no significant change in the accuracy of the predicted surf zone hydrodyanmics indicating that the large‐scale offshore features (e.g., submarine canyon) predominately control the nearshore wave‐circulation system.

Exploring the hidden shallows: extensive reef development and resilience within the turbid nearshore Great Barrier Reef

NASA Astrophysics Data System (ADS)

Morgan, Kyle; Perry, Chris; Smithers, Scott; Johnson, Jamie; Daniell, James

2016-04-01

Mean coral cover on Australia's Great Barrier Reef (GBR) has reportedly declined by over 15% during the last 30 years. Climate change events and outbreaks of coral disease have been major drivers of degradation, often exacerbating the stresses caused by localised human activities (e.g. elevated sediment and nutrient inputs). Here, however, in the first assessment of nearshore reef occurrence and ecology across meaningful spatial scales (15.5 sq km), we show that areas of the GBR shelf have exhibited strong intra-regional variability in coral resilience to declining water quality. Specifically, within the highly-turbid "mesophotic" nearshore (<10 m depth) of the central GBR, where terrigenous seafloor sediments are persistently resuspended by wave processes, coral cover averages 38% (twice that reported on mid- and outer-shelf reefs). Of the mapped area, 11% of the seafloor has distinct reef or coral community cover, a density comparable to that measured across the entire GBR shelf (9%). Identified coral taxa (21 genera) exhibited clear depth-stratification corresponding closely to light attenuation and seafloor topography. Reefs have accreted relatively rapidly during the late-Holocene (1.8-3.0 mm y-1) with rates of vertical reef growth influenced by intrinsic shifts in coral assemblages associated with reef development. Indeed, these shallow-water reefs may have similar potential as refugia from large-scale disturbance as their deep-water (>30 m) "mesophotic" equivalents, and also provide a basis from which to model future trajectories of reef growth within nearshore areas.

Terrestrial and marine trophic pathways support young-of-year growth in a nearshore Arctic fish

USGS Publications Warehouse

von Biela, Vanessa R.; Zimmerman, Christian E.; Cohn, Brian R.; Welker, Jeffrey M.

2013-01-01

River discharge supplies nearshore communities with a terrestrial carbon source that is often reflected in invertebrate and fish consumers. Recent studies in the Beaufort Sea have documented widespread terrestrial carbon use among invertebrates, but only limited use among nearshore fish consumers. Here, we examine the carbon source and diet of rapidly growing young-of-year Arctic cisco (Coregonus autumnalis) using stable isotope values (δ13C and δ15N) from muscle and diet analysis (stomach contents) during a critical and previously unsampled life stage. Stable isotope values (δ15N and δ13C) may differentiate between terrestrial and marine sources and integrate over longer time frames (weeks). Diet analysis provides species-specific information, but only from recent foraging (days). Average δ13C for all individuals was −25.7 ‰, with the smallest individuals possessing significantly depleted δ13C values indicative of a stronger reliance of terrestrial carbon sources as compared to larger individuals. Average δ15N for all individuals was 10.4 ‰, with little variation among individuals. As fish length increased, the proportion of offshore Calanus prey and neritic Mysis prey increased. Rapid young-of-year growth in Arctic cisco appears to use terrestrial carbon sources obtained by consuming a mixture of neritic and offshore zooplankton. Shifts in the magnitude or phenology of river discharge and the delivery of terrestrial carbon may alter the ecology of nearshore fish consumers.

A description of the nearshore fish communities in the Huron-Erie Corridor using multiple gear types

USGS Publications Warehouse

Francis, James T.; Chiotti, Justin A.; Boase, James C.; Thomas, Mike V.; Manny, Bruce A.; Roseman, Edward F.

2013-01-01

Great Lakes coastal wetlands provide a critical habitat for many fish species throughout their life cycles. Once home to one of the largest wetland complexes in the Great Lakes, coastal wetlands in the Huron–Erie Corridor (HEC) have decreased dramatically since the early 1900s. We characterized the nearshore fish communities at three different wetland complexes in the HEC using electrofishing, seines, and fyke nets. Species richness was highest in the Detroit River (63), followed by the St. Clair Delta (56), and Western Lake Erie (47). The nearshore fish communities in the Detroit River and St. Clair Delta consisted primarily of shiners, bluntnose minnow, centrarchids, and brook silverside, while the Western Lake Erie sites consisted of high proportions of non-native taxa including common carp, gizzard shad, goldfish, and white perch. Species richness estimates using individual-based rarefaction curves were higher when using electrofishing data compared to fyke nets or seine hauls at each wetland. Twelve fish species were captured exclusively during electrofishing assessments, while one species was captured exclusively in fyke nets, and none exclusively during seine hauls. Western Lake Erie wetlands were more indicative of degraded systems with lower species richness, lower proportion of turbidity intolerant species, and increased abundance of non-native taxa. This work highlights the importance of coastal wetlands in the HEC by capturing 69 different fish species utilizing these wetlands to fulfill life history requirements and provides insight when selecting gears to sample nearshore littoral areas.

Geology and total petroleum systems of the Paradox Basin, Utah, Colorado, New Mexico, and Arizona

USGS Publications Warehouse

Whidden, Katherine J.; Lillis, Paul G.; Anna, Lawrence O.; Pearson, Krystal M.; Dubiel, Russell F.

2014-01-01

The most studied source intervals are the Pennsylvanian black shales that were deposited during relative high stands in an otherwise evaporitic basin. These black shales are the source for most of the discovered hydrocarbons in the Paradox Basin. A second oil type can be traced to either a Mississippian or Permian source rock to the west, and therefore requires long-distance migration to explain its presence in the basin. Upper Cretaceous continental to nearshore-marine sandstones are interbedded with coal beds that have recognized coalbed methane potential. Precambrian and Devonian TPSs are considered hypothetical, as both are known to have organic-rich intervals, but no discovered hydrocarbons have been definitively typed back to either of these units.

Data-Driven Boundary Correction and Optimization of a Nearshore Wave and Hydrodynamic Model to Enable Rapid Environmental Assessment

DTIC Science & Technology

2011-09-30

Number : N00014 N00014-09-1-0503 http://ceprofs.civil.tamu.edu/jkaihatu/research/proj.html LONG-TERM GOALS The present project is part of a... number . 1. REPORT DATE 30 SEP 2011 2. REPORT TYPE 3. DATES COVERED 00-00-2011 to 00-00-2011 4. TITLE AND SUBTITLE Data-Driven Boundary...Correction and Optimization of a Nearshore Wave and Hydrodynamic Model to Enable Rapid Environmental Assessment 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c

Historical bathymetry and bathymetric change in the Mississippi-Alabama coastal region, 1847-2009

USGS Publications Warehouse

Buster, Noreen A.; Morton, Robert A.

2011-01-01

Land loss and seafloor change around the Mississippi and Alabama (MS-AL) barrier islands are of great concern to the public and to local, state, and federal agencies. The islands provide wildlife protected areas and recreational land, and they serve as a natural first line of defense for the mainland against storm activity (index map on poster). Principal physical conditions that drive morphological seafloor and coastal change in this area include decreased sediment supply, sea-level rise, storms, and human activities (Otvos, 1970; Byrnes and others, 1991; Morton and others, 2004; Morton, 2008). Seafloor responses to the same processes can also affect the entire coastal zone. Sediment eroded from the barrier islands is entrained in the littoral system, where it is redistributed by alongshore currents. Wave and current activity is partially controlled by the profile of the seafloor, and this interdependency along with natural and anthropogenic influences has significant effects on nearshore environments. When a coastal system is altered by human activity such as dredging, as is the case of the MS-AL coastal region, the natural state and processes are altered, and alongshore sediment transport can be disrupted. As a result of deeply dredged channels, adjacent island migration is blocked, nearshore environments downdrift in the littoral system become sediment starved, and sedimentation around the channels is modified. Sediment deposition and erosion are reflected through seafloor evolution. In a rapidly changing coastal environment, understanding historically where and why changes are occurring is essential. To better assess the comprehensive dynamics of the MS-AL coastal zone, a 160-year evaluation of the bathymetry and bathymetric change of the region was conducted.

Declining Coral Skeletal Extension for Forereef Colonies of Siderastrea siderea on the Mesoamerican Barrier Reef System, Southern Belize

PubMed Central

Castillo, Karl D.; Ries, Justin B.; Weiss, Jack M.

2011-01-01

Background Natural and anthropogenic stressors are predicted to have increasingly negative impacts on coral reefs. Understanding how these environmental stressors have impacted coral skeletal growth should improve our ability to predict how they may affect coral reefs in the future. We investigated century-scale variations in skeletal extension for the slow-growing massive scleractinian coral Siderastrea siderea inhabiting the forereef, backreef, and nearshore reefs of the Mesoamerican Barrier Reef System (MBRS) in the western Caribbean Sea. Methodology/Principal Findings Thirteen S. siderea cores were extracted, slabbed, and X-rayed. Annual skeletal extension was estimated from adjacent low- and high-density growth bands. Since the early 1900s, forereef S. siderea colonies have shifted from exhibiting the fastest to the slowest average annual skeletal extension, while values for backreef and nearshore colonies have remained relatively constant. The rates of change in annual skeletal extension were −0.020±0.005, 0.011±0.006, and −0.008±0.006 mm yr−1 per year [mean±SE] for forereef, backreef, and nearshore colonies respectively. These values for forereef and nearshore S. siderea were significantly lower by 0.031±0.008 and by 0.019±0.009 mm yr−1 per year, respectively, than for backreef colonies. However, only forereef S. siderea exhibited a statistically significant decline in annual skeletal extension over the last century. Conclusions/Significance Our results suggest that forereef S. siderea colonies are more susceptible to environmental stress than backreef and nearshore counterparts, which may have historically been exposed to higher natural baseline stressors. Alternatively, sediment plumes, nutrients, and pollution originating from watersheds of Guatemala and Honduras may disproportionately impact the forereef environment of the MBRS. We are presently reconstructing the history of environmental stressors that have impacted the MBRS to constrain the cause(s) of the observed reductions in coral skeletal growth. This should improve our ability to predict and potentially mitigate the effects of future environmental stressors on coral reef ecosystems. PMID:21359203

Vertical Distribution of Radiation Stress for Non-linear Shoaling Waves

NASA Astrophysics Data System (ADS)

Webb, B. M.; Slinn, D. N.

2004-12-01

The flux of momentum directed shoreward by an incident wave field, commonly referred to as the radiation stress, plays a significant role in nearshore circulation and, therefore, has a profound impact on the transport of pollutants, biota, and sediment in nearshore systems. Having received much attention since the seminal work of Longuet-Higgins and Stewart in the early 1960's, use of the radiation stress concept continues to be refined and evidence of its utility is widespread in literature pertaining to coastal and ocean science. A number of investigations, both numerical and analytical in nature, have used the concept of the radiation stress to derive appropriate forcing mechanisms that initiate cross-shore and longshore circulation, but typically in a depth-averaged sense due to a lack of information concerning the vertical distribution of the wave stresses. While depth-averaged nearshore circulation models are still widely used today, advancements in technology have permitted the adaptation of three-dimensional (3D) modeling techniques to study flow properties of complex nearshore circulation systems. It has been shown that the resulting circulation in these 3D models is very sensitive to the vertical distribution of the nearshore forcing, which have often been implemented as either depth-uniform or depth-linear distributions. Recently, analytical expressions describing the vertical structure of radiation stress components have appeared in the literature (see Mellor, 2003; Xia et al., 2004) but do not fully describe the magnitude and structure in the region bound by the trough and crest of non-linear, propagating waves. Utilizing a three-dimensional, non-linear, numerical model that resolves the time-dependent free surface, we present mean flow properties resulting from a simulation of Visser's (1984, 1991) laboratory experiment on uniform longshore currents. More specifically, we provide information regarding the vertical distribution of radiation stress components (Sxx and Sxy) resulting from obliquely incident, non-linear shoaling waves. Vertical profiles of the radiation stress components predicted by the numerical model are compared with published analytical solutions, expressions given by linear theory, and observations from an investigation employing second-order cnoidal wave theory.

Nearshore habitat and fish community associations of coaster brook trout in Isle Royale, Lake Superior

USGS Publications Warehouse

Gorman, O.T.; Moore, S.A.; Carlson, A.J.; Quinlan, H.R.

2008-01-01

We characterized the nearshore habitat and fish community composition of approximately 300 km of shoreline within and adjacent to the major embayments of Isle Royale, Lake Superior. Sampling yielded 17 species, of which 12 were widespread and represented a common element of the Lake Superior fish community, including cisco Coregonus artedi, lake whitefish C. clupeaformis, round whitefish Prosopium cylindraceum, lake trout Salvelinus namaycush, rainbow smelt Osmerus mordax, lake chub Couesius plumbeus, longnose sucker Catostomus catostomus, white sucker C. commersonii, trout-perch Percopsis omiscomaycus, ninespine stickleback Pungitius pungitius, burbot Lota lota, and slimy sculpin Cottus cognatus. The presence of brook trout S. fontinalis in an embayment was associated with the common species of the Isle Royale nearshore fish community, particularly cisco, longnose sucker, and round whitefish. However, brook trout were present in only five embayments and were common only in Tobin Harbor. Most Isle Royale embayments had broadly overlapping ranges of nearshore habitats. Within embayments, fish were distributed along a habitat gradient from less-protected rocky habitat near the mouth to highly protected habitat with mixed and finer substrates at the head. Embayments with brook trout had greater mean protection from the open lake, greater variation in depth, greater mean cover, and higher mean frequencies of large substrates (cobble, boulder, and bedrock). Within those embayments, brook trout were associated with habitat patches with higher mean frequencies of small substrates (particularly sand and coarse gravel). Within Tobin Harbor, brook trout were associated with midembayment habitat and species assemblages, especially those locations with a mixture of sand, gravel, and cobble substrates, an absence of bedrock, and the presence of round whitefish, white sucker, and trout-perch. Comparison of embayments with the model, Tobin Harbor, showed that six embayments without brook trout had very similar arrays of habitat. However, four embayments with brook trout had relatively different arrays of habitat from Tobin Harbor. These results suggest that there is potential for further recovery of brook trout populations across Isle Royale nearshore habitats. ?? Copyright by the American Fisheries Society 2008.

Latitudinal Discontinuity in Thermal Conditions along the Nearshore of Central-Northern Chile

PubMed Central

Tapia, Fabian J.; Largier, John L.; Castillo, Manuel; Wieters, Evie A.; Navarrete, Sergio A.

2014-01-01

Over the past decade, evidence of abrupt latitudinal changes in the dynamics, structure and genetic variability of intertidal and subtidal benthic communities along central-northern Chile has been found consistently at 30–32°S. Changes in the advective and thermal environment in nearshore waters have been inferred from ecological patterns, since analyses of in situ physical data have thus far been missing. Here we analyze a unique set of shoreline temperature data, gathered over 4–10 years at 15 sites between 28–35°S, and combine it with satellite-derived winds and sea surface temperatures to investigate the latitudinal transition in nearshore oceanographic conditions suggested by recent ecological studies. Our results show a marked transition in thermal conditions at 30–31°S, superimposed on a broad latitudinal trend, and small-scale structures associated with cape-and-bay topography. The seasonal cycle dominated temperature variability throughout the region, but its relative importance decreased abruptly south of 30–31°S, as variability at synoptic and intra-seasonal scales became more important. The response of shoreline temperatures to meridional wind stress also changed abruptly at the transition, leading to a sharp drop in the occurrence of low-temperature waters at northern sites, and a concurrent decrease in corticated algal biomass. Together, these results suggest a limitation of nitrate availability in nearshore waters north of the transition. The localized alongshore change results from the interaction of latitudinal trends (e.g., wind stress, surface warming, inertial period) with a major headland-bay system (Punta Lengua de Vaca at 30.25°S), which juxtaposes a southern stretch of coast characterized by upwelling with a northern stretch of coast characterized by warm surface waters and stratification. This transition likely generates a number of latitude-dependent controls on ecological processes in the nearshore that can explain species-specific effects, and add strength to the suggestion of an oceanography-driven, major spatial transition in coastal communities at 30–31°S. PMID:25334020

Geological evidence and sediment transport modelling for the 1946 and 1960 tsunamis in Shinmachi, Hilo, Hawaii

NASA Astrophysics Data System (ADS)

Chagué, Catherine; Sugawara, Daisuke; Goto, Kazuhisa; Goff, James; Dudley, Walter; Gadd, Patricia

2018-02-01

The Japanese community of Shinmachi, established on low-lying land between downtown Hilo and Waiakea, Hawaii, was obliterated by the 1946 Aleutian tsunami but was rebuilt, only to be destroyed again by the 1960 Chilean tsunami. The aim of this study was to find out if any geological evidence of these well documented events had been preserved in the sedimentary record in Wailoa River State Park, which replaced Shinmachi after the 1960 tsunami. This was achieved by collecting cores in the park and performing sedimentological, chronological and geochemical analyses, the latter also processed by principal component analysis. Sediment transport modelling was carried out for both tsunamis, to infer the source of the sediment and areas of deposition on land. The field survey revealed two distinct units within peat and soil, a thin lower unit composed of weathered basalt fragments within mud (Unit 1) and an upper unit dominated by fine volcanic sand within fine silt exhibiting subtle upward fining and coarsening (Unit 2, consisting of Unit 2A and Unit 2B), although these two anomalous units only occur on the western shore of Waiakea Mill Pond. Analysis with an ITRAX core scanner shows that Unit 1 is characterised by high Mn, Fe, Rb, La and Ce counts, combined with elevated magnetic susceptibility. Based on its chemical and sedimentological characteristics, Unit 1 is attributed to a flood event in Wailoa River that occurred around 1520-1660 CE, most probably as a result of a tropical storm. The sharp lower contact of Unit 2 coincides with the appearance of arsenic, contemporaneous with an increase in Ca, Sr, Si, Ti, K, Zr, Mn, Fe, La and Ce. In this study, As is used as a chronological and source material marker, as it is known to have been released into Wailoa River Estuary and Waiakea Mill Pond by the Canec factory between 1932 and 1963. Thus, not only the chemical and sedimentological evidence but also sediment transport modelling, corroborating the historical record, suggest that Unit 2A was deposited by the 1946 tsunami, and the sediment most likely originated from Wailoa River Estuary, beach and nearshore seafloor. The upper part of this unit, Unit 2B, is believed to have been deposited by the 1960 tsunami, as suggested by sediment transport modelling, although limited accommodation space is likely to have resulted in the thin deposit (3 cm thickness) present at that site. Limited accommodation space on the island of Hawaii has led to only rare locations where tsunami deposits are preserved, despite the repeated occurrence of tsunamis affecting the island.

Using science to strengthen our Nation's resilience to tomorrow's challenges: understanding and preparing for coastal impacts

USGS Publications Warehouse

Simmons, Dale L.; Andersen, Matthew E.; Dean, Teresa A.; Focazio, Michael J.; Fulton, John W.; Haines, John W.; Mason, Jr., Robert R.; Tihansky, Ann B.; Young, John A.

2014-01-01

Hurricane Sandy caused unprecedented damage across some of the most densely populated coastal areas of the northeastern United States. The costly, landscape-altering destruction left in the wake of this storm is a stark reminder of our Nation’s need to become more resilient as we inevitably face future coastal hazards. As our Nation recovers from this devastating natural disaster, it is clear that accurate scientific information is essential as we seek to identify and develop strategies to address trends in coastal landscape change and reduce our future vulnerability to major storm events. To address this need, the U.S. Geological Survey (USGS) received $43.2 million in supplemental appropriations from the Department of the Interior (DOI) to conduct the scientific research needed to guide response, recovery, and rebuilding activities and to develop effective strategies for protecting coastal communities and resources in the future. This fact sheet describes how the USGS is combining interdisciplinary science with state-of-the-art technologies to achieve a comprehensive understanding of coastal change caused by Hurricane Sandy. By assessing coastal change impacts through research and by developing tools that enhance our science capabilities, support coastal stakeholders, and facilitate effective decision making, we continue to build a greater understanding of the processes at work across our Nation’s complex coastal environment—from wetlands, estuaries, barrier islands, and nearshore marine areas to infrastructure and human communities. This improved understanding will increase our resilience as we prepare for future short-term, extreme events as well as long-term coastal change.

Observation of wave celerity evolution in the nearshore using digital video imagery

NASA Astrophysics Data System (ADS)

Yoo, J.; Fritz, H. M.; Haas, K. A.; Work, P. A.; Barnes, C. F.; Cho, Y.

2008-12-01

Celerity of incident waves in the nearshore is observed from oblique video imagery collected at Myrtle Beach, S.C.. The video camera covers the field view of length scales O(100) m. Celerity of waves propagating in shallow water including the surf zone is estimated by applying advanced image processing and analysis methods to the individual video images sampled at 3 Hz. Original image sequences are processed through video image frame differencing, directional low-pass image filtering to reduce the noise arising from foam in the surf zone. The breaking wave celerity is computed along a cross-shore transect from the wave crest tracks extracted by a Radon transform-based line detection method. The observed celerity from the nearshore video imagery is larger than the linear wave celerity computed from the measured water depths over the entire surf zone. Compared to the nonlinear shallow water wave equation (NSWE)-based celerity computed using the measured depths and wave heights, in general, the video-based celerity shows good agreements over the surf zone except the regions across the incipient wave breaking locations. In the regions across the breaker points, the observed wave celerity is even larger than the NSWE-based celerity due to the transition of wave crest shapes. The observed celerity using the video imagery can be used to monitor the nearshore geometry through depth inversion based on the nonlinear wave celerity theories. For this purpose, the exceeding celerity across the breaker points needs to be corrected accordingly compared to a nonlinear wave celerity theory applied.

Habitat coupling in a large lake system: delivery of an energy subsidy by an offshore planktivore to the nearshore zone of Lake Superior

USGS Publications Warehouse

Stockwell, Jason D.; Yule, Daniel L.; Hrabik, Thomas R.; Sierszen, Michael E.; Isaac, Edmund J.

2014-01-01

1. We hypothesised that the autumn spawning migration of Lake Superior cisco (Coregonus artedi) provides a resource subsidy, in the form of energy-rich cisco eggs, from the offshore pelagic to the nearshore benthic community over winter, when alternate prey production is likely to be low. 2. We tested this hypothesis using fish and macroinvertebrate surveys, fish population demographics, diet and stable isotope analyses, and bioenergetics modelling. 3. The benthic, congeneric lake whitefish (C. clupeaformis) was a clear beneficiary of cisco spawning. Cisco eggs represented 16% of lake whitefish annual consumption in terms of biomass, but 34% of energy (because of their high energy density: >10 kJ g wet mass−1). Stable isotope analyses were consistent with these results and suggest that other nearshore fish species may also rely on cisco eggs. 4. The lipid content of lake whitefish liver almost doubled from 26 to 49% between November and March, while that of muscle increased from 14 to 26% over the same period, suggesting lake whitefish were building, rather than depleting, lipid reserves during winter. 5. In the other Laurentian Great Lakes, where cisco populations remain very low and rehabilitation efforts are underway, the offshore-to-nearshore ecological link apparent in Lake Superior has been replaced by non-native planktivorous species. These non-native species spawn in spring have smaller eggs and shorter incubation periods. The rehabilitation of cisco in these systems should reinstate the onshore subsidy as it has in Lake Superior.

Granulometry and mineralogy of some northeastern Florida placers: a consequence of heavy mineral concentration in nearshore bars

NASA Astrophysics Data System (ADS)

Elsner, Harald

1992-03-01

Heavy mineral placer deposits of Pleistocene age in northeastern Florida were examined sedimentologically. Neither general setting, nor granulometric or mineralogic results are in agreement with a concentration of the heavy minerals in a beach, eolian or fluvial environment. Granulometric moment parameters of the ore sands seem to be distinctive. They include moderate sorting, high positive skewness, high kurtosis and a distinctive fine tail. Similarities of grain size curves of the placer sands with nearshore-offshore sands exist. Mineralogically the samples are more variable but always impoverished in epidote. This scarcity of epidote is atypical for eolian sediments in the study area, and the lack of garnet and the fineness of ore sands are uncommon for beach placers of northeast Florida. Underlain by dune ridges, which acted as obstacles on the shallow sea floor during the Penholoway transgression (1.3 ± 0.1 Ma B.P.), heavy minerals in the Boulogne and Green Cove Springs main ore body must have been concentrated in bars by the interplay of longshore and transverse bottom currents. Lighter heavy minerals were deposited in smaller nearshore bars closer to the former coast (Green Cove Springs small ore body) or in dunes of barrier islands (Green Cove Springs western ore body). As is true today, layers of noteworthy concentrations of economic minerals in the swash zone of Florida beaches were formed only rarely during storms, contrary to the coasts of Australia or India, where higher energetic conditions prevail. The proposed model of concentration of heavy minerals in certain outer nearshore bars has long been assumed but never been proven.

Effect of surficial disturbance on exchange between groundwater and surface water in nearshore margins

USGS Publications Warehouse

Rosenberry, Donald O.; Toran, Laura; Nyquist, Jonathan E.

2010-01-01

Low‐permeability sediments situated at or near the sediment‐water interface can influence seepage in nearshore margins, particularly where wave energy or currents are minimal. Seepage meters were used to quantify flow across the sediment‐water interface at two lakes where flow was from surface water to groundwater. Disturbance of the sediment bed substantially increased seepage through the sandy sediments of both lakes. Seepage increased by factors of 2.6 to 7.7 following bed disturbance at seven of eight measurement locations at Mirror Lake, New Hampshire, where the sediment representing the greatest restriction to flow was situated at the sediment‐water interface. Although the veneer of low‐permeability sediment was very thin and easily disturbed, accumulation on the bed surface was aided by a physical setting that minimized wind‐generated waves and current. At Lake Belle Taine, Minnesota, where pre‐disturbance downward seepage was smaller than at Mirror Lake, but hydraulic gradients were very large, disturbance of a 20 to 30 cm thick medium sand layer resulted in increases in seepage of 2 to 3 orders of magnitude. Exceptionally large seepage rates, some exceeding 25,000 cm/d, were recorded following bed disturbance. Since it is common practice to walk on the bed while installing or making seepage measurements, disruption of natural seepage rates may be a common occurrence in nearshore seepage studies. Disturbance of the bed should be avoided or minimized when utilizing seepage meters in shallow, nearshore settings, particularly where waves or currents are infrequent or minimal.

Contrasting effect of Saharan dust and UVR on autotrophic picoplankton in nearshore versus offshore waters of Mediterranean Sea

NASA Astrophysics Data System (ADS)

González-Olalla, J. M.; Medina-Sánchez, J. M.; Cabrerizo, M. J.; Villar-Argáiz, Manuel; Sánchez-Castillo, Pedro M.; Carrillo, Presentación

2017-08-01

Autotrophic picoplankton (APP) is responsible for the vast majority of primary production in oligotrophic marine areas, such as the Alboran Sea. The increase in atmospheric dust deposition (e.g., from Sahara Desert) associated with global warming, together with the high UV radiation (UVR) on these ecosystems, may generate effects on APP hitherto unknown. We performed an observational study across the Alboran Sea to establish which factors control the abundance and distribution of APP, and we made a microcosm experiment in two distinct areas, nearshore and offshore, to predict the joint UVR × dust impact on APP at midterm scales. Our observational study showed that temperature (T) was the main factor explaining the APP distribution whereas total dissolved nitrogen positively correlated with APP abundance. Our experimental study revealed that Saharan dust inputs reduced or inverted the UVR damage on the photosynthetic quantum yield (ΦPSII) and picoplanktonic primary production (PPP) in the nearshore area but accentuated it in the offshore. This contrasting effect is partially explained by the nonphotochemical quenching, acting as a photorepair mechanism. Picoeukaryotes reflected the observed effects on the physiological and metabolic variables, and Synechococcus was the only picoprokaryotic group that showed a positive response under UVR × dust conditions. Our study highlights a dual sensitivity of nearshore versus offshore picoplankton to dust inputs and UVR fluxes, just at the time in which these two global-change factors show their highest intensities and may recreate a potential future response of the microbial food web under global-change conditions.

Persistent shoreline shape induced from offshore geologic framework: Effects of shoreface connected ridges

USGS Publications Warehouse

Safak, Ilgar; List, Jeffrey; Warner, John C.; Schwab, William C.

2017-01-01

Mechanisms relating offshore geologic framework to shoreline evolution are determined through geologic investigations, oceanographic deployments, and numerical modeling. Analysis of shoreline positions from the past 50 years along Fire Island, New York, a 50 km long barrier island, demonstrates a persistent undulating shape along the western half of the island. The shelf offshore of these persistent undulations is characterized with shoreface-connected sand ridges (SFCR) of a similar alongshore length scale, leading to a hypothesis that the ridges control the shoreline shape through the modification of flow. To evaluate this, a hydrodynamic model was configured to start with the US East Coast and scale down to resolve the Fire Island nearshore. The model was validated using observations along western Fire Island and buoy data, and used to compute waves, currents and sediment fluxes. To isolate the influence of the SFCR on the generation of the persistent shoreline shape, simulations were performed with a linearized nearshore bathymetry to remove alongshore transport gradients associated with shoreline shape. The model accurately predicts the scale and variation of the alongshore transport that would generate the persistent shoreline undulations. In one location, however, the ridge crest connects to the nearshore and leads to an offshore-directed transport that produces a difference in the shoreline shape. This qualitatively supports the hypothesized effect of cross-shore fluxes on coastal evolution. Alongshore flows in the nearshore during a representative storm are driven by wave breaking, vortex force, advection and pressure gradient, all of which are affected by the SFCR.

Evaluating the importance of abiotic and biotic drivers on Bythotrephes biomass in Lakes Superior and Michigan

USGS Publications Warehouse

Keeler, Kevin M.; Bunnell, David B.; Diana, James S.; Adams, Jean V.; Mychek-Londer, Justin G.; Warner, David M.; Yule, Daniel; Vinson, Mark

2015-01-01

The ability of planktivorous fishes to exert top-down control on Bythotrephes potentially has far-reaching impacts on aquatic food-webs, given previously described effects of Bythotrephes on zooplankton communities. We estimated consumption of Bythotrephes by planktivorous and benthivorous fishes, using bioenergetics and daily ration models at nearshore (18 m), intermediate (46 m), and offshore (110 m) depths along one western Lake Superior transect (April, and September-November) and two northern Lake Michigan transects (April, July, September). In Lake Superior, consumption (primarily by cisco Coregonus artedi) exceeded Bythotrephes production at all offshore sites in September-November (up to 396% of production consumed) and at the intermediate site in November (842%) with no evidence of consumption nearshore. By comparing Bythotrephes biomass following months of excessive consumption, we conservatively concluded that top-down control was evident only at the offshore site during September-October. In Lake Michigan, consumption by fishes (primarily alewife Alosa pseudoharengus) exceeded production at nearshore sites (up to 178%), but not in deeper sites (< 15%). Evidence for top-down control in the nearshore was not supported, however, as Bythotrephes never subsequently declined. Using generalized additive models, temperature, and not fish consumption, not zooplankton prey density, best explained variability in Bythotrephes biomass. The non-linear pattern revealed Bythotrephes to increase with temperature up to 16 °C, and then decline between 16 and 23 °C. We discuss how temperature likely has direct negative impacts on Bythotrephes when temperatures near 23 °C, but speculate that predation also contributes to declining biomass when temperatures exceed 16 °C.

Seabird use of discards from a nearshore shrimp fishery in the South Atlantic Bight, USA

USGS Publications Warehouse

Jodice, Patrick G.R.; Wickliffe, Lisa C.; Sachs, Elena B.

2011-01-01

Shrimp trawling is common throughout the southeastern and Gulf of Mexico coasts of the USA and is the primary contributor to fisheries discards in these regions. Tens of thousands of nearshore seabirds nest near shrimp trawling grounds in the USA, but to date, there has been no assessment of the relationship between seabirds and shrimp trawlers. We examined the taxonomic composition of bycatch, rate at which seabirds scavenged bycatch, and energy density of discarded bycatch in a nearshore commercial shrimp fishery. Bycatch was primarily comprised of demersal fish that are not typically accessible to the plunge-diving and surface-feeding seabirds that occur in the area. Hence, seabird diets in the region appear to be broadened taxonomically by the availability of discards. Results from discard experiments indicated that 70% of the nearly 5,500 items discarded by hand were scavenged by seabirds and that the fate of a discarded item was most strongly predicted by its taxonomic order. Laughing gulls scavenged the greatest proportion of discards, although brown pelicans were the only species to scavenge more discards than predicted based upon their abundance. Because this is the first such study in the region, it is difficult to ascertain the extent or intensity of the impact that discards have on nearshore seabirds. Nonetheless, our results suggest that it will be difficult for managers to clearly understand fluctuations in local seabird population dynamics without first understanding the extent to which these species rely upon discards. This may be especially problematic in situations where seabird populations are recovering following natural or anthropogenic stressors.

Shrimp trawlers as a local attractor of seabirds in nearshore waters of South Carolina, USA

USGS Publications Warehouse

Jodice, Patrick G.R.; Wickliffe, Lisa C.; Sachs, Elena B.

2011-01-01

Shrimp trawling is common throughout the southeastern and Gulf of Mexico coasts of the USA and is the primary contributor to fisheries discards in these regions. Tens of thousands of nearshore seabirds nest near shrimp trawling grounds in the USA, but to date, there has been no assessment of the relationship between seabirds and shrimp trawlers. We examined the taxonomic composition of bycatch, rate at which seabirds scavenged bycatch, and energy density of discarded bycatch in a nearshore commercial shrimp fishery. Bycatch was primarily comprised of demersal fish that are not typically accessible to the plunge-diving and surface-feeding seabirds that occur in the area. Hence, seabird diets in the region appear to be broadened taxonomically by the availability of discards. Results from discard experiments indicated that 70% of the nearly 5,500 items discarded by hand were scavenged by seabirds and that the fate of a discarded item was most strongly predicted by its taxonomic order. Laughing gulls scavenged the greatest proportion of discards, although brown pelicans were the only species to scavenge more discards than predicted based upon their abundance. Because this is the first such study in the region, it is difficult to ascertain the extent or intensity of the impact that discards have on nearshore seabirds. Nonetheless, our results suggest that it will be difficult for managers to clearly understand fluctuations in local seabird population dynamics without first understanding the extent to which these species rely upon discards. This may be especially problematic in situations where seabird populations are recovering following natural or anthropogenic stressors.

Alongshore momentum transfer to the nearshore zone from energetic ocean waves generated by passing hurricanes

NASA Astrophysics Data System (ADS)

Mulligan, Ryan P.; Hanson, Jeffrey L.

2016-06-01

Wave and current measurements from a cross-shore array of nearshore sensors in Duck, NC, are used to elucidate the balance of alongshore momentum under energetic wave conditions with wide surf zones, generated by passing hurricanes that are close to and far from to the coast. The observations indicate that a distant storm (Hurricane Bill, 2009) with large waves has low variability in directional wave characteristics resulting in alongshore currents that are driven mainly by the changes in wave energy. A storm close to the coast (Hurricane Earl, 2010), with strong local wind stress and combined sea and swell components in wave energy spectra, has high variability in wave direction and wave period that influence wave breaking and nearshore circulation as the storm passes. During both large wave events, the horizontal current shear is strong and radiation stress gradients, bottom stress, wind stress, horizontal mixing, and cross-shore advection contribute to alongshore momentum at different spatial locations across the nearshore region. Horizontal mixing during Hurricane Earl, estimated from rotational velocities, was particularly strong suggesting that intense eddies were generated by the high horizontal shear from opposing wind-driven and wave-driven currents. The results provide insight into the cross-shore distribution of the alongshore current and the connection between flows inside and outside the surf zone during major storms, indicating that the current shear and mixing at the interface between the surf zone and shallow inner shelf is strongly dependent on the distance from the storm center to the coast.

Evidence of bottom-up limitations in nearshore marine systems based on otolith proxies of fish growth

USGS Publications Warehouse

von Biela, Vanessa R.; Kruse, Gordon H.; Mueter, Franz J.; Black, Bryan A.; Douglas, David C.; Helser, Thomas E.; Zimmerman, Christian E.

2015-01-01

Fish otolith growth increments were used as indices of annual production at nine nearshore sites within the Alaska Coastal Current (downwelling region) and California Current (upwelling region) systems (~36–60°N). Black rockfish (Sebastes melanops) and kelp greenling (Hexagrammos decagrammus) were identified as useful indicators in pelagic and benthic nearshore food webs, respectively. To examine the support for bottom-up limitations, common oceanographic indices of production [sea surface temperature (SST), upwelling, and chlorophyll-a concentration] during summer (April–September) were compared to spatial and temporal differences in fish growth using linear mixed models. The relationship between pelagic black rockfish growth and SST was positive in the cooler Alaska Coastal Current and negative in the warmer California Current. These contrasting growth responses to SST among current systems are consistent with the optimal stability window hypothesis in which pelagic production is maximized at intermediate levels of water column stability. Increased growth rates of black rockfish were associated with higher chlorophyll concentrations in the California Current only, but black rockfish growth was unrelated to the upwelling index in either current system. Benthic kelp greenling growth rates were positively associated with warmer temperatures and relaxation of downwelling (upwelling index near zero) in the Alaska Coastal Current, while none of the oceanographic indices were related to their growth in the California Current. Overall, our results are consistent with bottom-up forcing of nearshore marine ecosystems—light and nutrients constrain primary production in pelagic food webs, and temperature constrains benthic food webs.

In-situ Geotechnical Investigation of Arctic Nearshore Zone Sediments, Herschel Island, Yukon

NASA Astrophysics Data System (ADS)

Stark, N.; Quinn, B.; Radosavljevic, B.; Lantuit, H.

2016-02-01

The Arctic is currently undergoing rapid changes with regard to ice coverage, permafrost retreat and coastal erosion. In addition to hydrodynamic processes, the sediments in the Arctic nearshore zone are affected by potential variations in freeze-thaw cycles, as well as an increase of abundant suspended sediment introduced by active retrogressive thaw slumps and increased river discharge. During the YUKON14 expedition to Herschel Island, Yukon, in-situ geotechnical testing of nearshore zone sediments was conducted using a portable free fall penetrometer. The research goals were mapping of sediment types, identification of surficial sediment stratification related to recent sediment remobilization or deposition processes, and the investigation of the soil mechanical characteristics of the uppermost seabed surface in the nearshore zone. Approximately 200 sites were tested using the portable free fall penetrometer, and five different geotechnical signatures identified and grouped. Most locations were characterized by a soft sediment top layer that exhibited a noticeably lower sediment strength than the underlying sediment. The results were correlated to existing sediment grain size records and a sediment type interpretation based on side scan sonar backscatter information. Strong spatial variations in sediment type and stiffness were observed, as well as in abundance and thickness of a top layer of very soft and loose sediment. It was attempted to relate the geotechnical signature to site-specific hydrodynamic energy, morphology, and vicinity to thaw slumps. The results will contribute to a detailed investigation of Arctic coastal erosion in the region, and the investigation of the role of geotechnical parameters for Arctic coastal erosion.

Nutrients, phytoplankton, zooplankton, and macrobenthos

USGS Publications Warehouse

Rudstam, Lars G.; Holeck, Kristen T.; Watkins, James M.; Hotaling, Christopher; Lantry, Jana R.; Bowen, Kelly L.; Munawar, Mohi; Weidel, Brian C.; Barbiero, Richard; Luckey, Frederick J.; Dove, Alice; Johnson, Timothy B.; Biesinger, Zy

2017-01-01

Lower trophic levels support the prey fish on which most sport fish depend. Therefore, understanding the production potential of lower trophic levels is integral to the management of Lake Ontario’s fishery resources. Lower trophic-level productivity differs among offshore and nearshore waters. In the offshore, there is concern about the ability of the lake to support Alewife (Table 1) production due to a perceived decline in productivity of phytoplankton and zooplankton whereas, in the nearshore, there is a concern about excessive attached algal production (e.g., Cladophora) associated with higher nutrient concentrations—the oligotrophication of the offshore and the eutrophication of the nearshore (Mills et al. 2003; Holeck et al. 2008; Dove 2009; Koops et al. 2015; Stewart et al. 2016). Even though the collapse of the Alewife population in Lake Huron in 2003 (and the associated decline in the Chinook Salmon fishery) may have been precipitated by a cold winter (Dunlop and Riley 2013), Alewife had not returned to high abundances in Lake Huron as of 2014 (Roseman et al. 2015). Failure of the Alewife population to recover from collapse has been attributed to declines in lower trophic-level production (Barbiero et al. 2011; Bunnell et al. 2014; but see He et al. 2015). In Lake Michigan, concerns of a similar Alewife collapse led to a decrease in the number of Chinook Salmon stocked. If lower trophic-level production declines in Lake Ontario, a similar management action could be considered. On the other hand, in Lake Erie, which supplies most of the water in Lake Ontario, eutrophication is increasing and so are harmful algal blooms. Thus, there is also a concern that nutrient levels and algal blooms could increase in Lake Ontario, especially in the nearshore. Solutions to the two processes of concern—eutrophication in the nearshore and oligotrophication in the offshore—may be mutually exclusive. In either circumstance, fisheries management needs information on the productivity of lower trophic levels in Lake Ontario. In this chapter, we review the status of lower trophic levels in Lake Ontario with special attention to the current (2008-2013) and previous (2003-2007) reporting periods. During the two reporting periods, three whole-lake surveys of lower trophic levels were conducted: the Lower Trophic Level Assessment (LOLA) in 2003 and 2008 (Makarewicz and Howell 2012; Munawar et al. 2015b) and the Cooperative Science and Management Initiative (CSMI) in 2013. Analyses of the CSMI data are ongoing. In addition to the three one-year sources of information on lower trophic levels, several multi-year sources of information are available, including data from the surveillance program conducted since 1965 by Environment Canada (EC) (Dove 2009), monitoring conducted since 1980 by the U.S. Environmental Protection Agency’s (EPA) Great Lakes National Program Office (GLNPO) (Barbiero et al. 2014; Reavie et al. 2014), sampling for a Bioindex Program at two stations, one offshore and one in the Eastern Basin, assessments of Mysis diluviana (formerly Mysis relicta) conducted since 1980 by Fisheries and Oceans Canada (Johannsson et al. 1998, 2011) and the Ontario Ministry of Natural Resources and Forestry (OMNRF), and monitoring conducted since 1995 by the Biomonitoring Program (BMP) on the New York side of the lake (Holeck et al. 2015b). The BMP is a collaboration of the New York State Department of Environmental Conservation (DEC), U.S. Fish and Wildlife Service, U.S. Geological Survey (USGS), and Cornell University.

Trophic connections in Lake Superior Part II: the nearshore fish community

USGS Publications Warehouse

Gamble, A.E.; Hrabik, T.R.; Yule, D.L.; Stockwell, J.D.

2011-01-01

We use detailed diet analyses of the predominant planktivorous, benthivorous and piscivorous fish species from Lake Superior to create a nearshore (bathymetric depths Mysis diluviana and Diporeia spp). Although the piscivorous fishes like lean lake trout (Salvelinus namaycush) fed to a lesser extent on Diporeia and Mysis, they were still strongly connected to these macroinvertebrates, which were consumed by their primary prey species (sculpin spp., rainbow smelt Osmerus mordax, and coregonines). The addition of Bythotrephes to summer/fall cisco and lake whitefish diets, and the decrease in rainbow smelt in lean lake trout diets (replaced by coregonines) were the largest observed differences relative to historic Lake Superior diet studies. Although the offshore food web of Lake Superior was simpler than nearshore in terms of number of fish species present, the two areas had remarkably similar food web structures, and both fish communities were primarily supported by Mysis and Diporeia. We conclude that declines in Mysis or Diporeia populations would have a significant impact on energy flow in Lake Superior. The food web information we generated can be used to better identify management strategies for Lake Superior.

Monitoring and modeling nearshore dredge disposal for indirect beach nourishment, Ocean Beach, San Francisco

USGS Publications Warehouse

Barnard, Patrick L.; Hanes, Daniel M.; Lescinski, Jamie; Elias, Edwin

2007-01-01

Nearshore dredge disposal was performed during the summer of 2005 at Ocean Beach, San Francisco, CA, a high energy tidal and wave environment. This trial run was an attempt to provide a buffer to a reach of coastline where wave attack during the winter months has had a severe impact on existing sewage infrastructure. Although the subsequent beach response was inconclusive, after one year the peak of the disposal mound had migrated ~100 m toward the shore, providing evidence that annual dredge disposal at this site could be beneficial over the long-term by at the very least providing: 1) additional wave dissipation during storms 2) compatible sediment to feed nearshore bars, 3) sediment cover on an exposed sewage outfall pipe, and 4) a viable alternative to the shoaling offshore disposal site. Numerical modeling suggests that despite the strong tidal currents in the region, wave forcing is the dominant factor moving the sediment slowly toward shore, and placing sediment at just slightly shallower depths (e.g. 9 m) in the future would have a more immediate impact.

An Ephemeral Dinoflagellate Bloom during Summer Season in Nearshore Water of Puri, East Coast of India

NASA Astrophysics Data System (ADS)

Baliarsingh, Sanjiba Kumar; Dwivedi, Rashmin; Lotliker, Aneesh A.; Jayashankar, Reeta; Sahu, Biraja Kumar; Srichandan, Suchismita; Samanta, Alakes; Parida, Chandanlal; Srinivasakumar, Tummala; Sahu, Kali Charan

2018-03-01

The present paper reports on the phenomenon of pinkish-red discoloration of the nearshore water of Puri, Odisha on 12th May 2016. Many local newspapers covered this event, as Puri city is a major tourist and pilgrimage place on the east coast of India. Field observations were carried out in order to provide a scientific basis to the event and to elicit possible causes of this discoloration. Taxonomic analysis of the phytoplankton samples revealed the dominance of red colored dinoflagellate species Gonyaulax polygramma, contributing 90% to total phytoplankton population. The localized concentration of G. polygramma was responsible for the pinkish-red discoloration of nearshore water. The exact factor that lay behind the genesis of this bloom could not be delineated due to the short period of its persistence. But two factors - upwelling and anthropogenic nutrient influx - can be viewed as the main cause for this ephemeral bloom. Non-hypoxic conditions in the coastal water following the ephemeral bloom event indicated no significant risk of ecological deterioration to the ambient medium.

Spatial and temporal correlation between beach and wave processes: implications for bar-berm sediment transition

NASA Astrophysics Data System (ADS)

Joevivek, V.; Chandrasekar, N.; Saravanan, S.; Anandakumar, H.; Thanushkodi, K.; Suguna, N.; Jaya, J.

2018-06-01

Investigation of a beach and its wave conditions is highly requisite for understanding the physical processes in a coast. This study composes spatial and temporal correlation between beach and nearshore processes along the extensive sandy beach of Nagapattinam coast, southeast peninsular India. The data collection includes beach profile, wave data, and intertidal sediment samples for 2 years from January 2011 to January 2013. The field data revealed significant variability in beach and wave morphology during the northeast (NE) and southwest (SW) monsoon. However, the beach has been stabilized by the reworking of sediment distribution during the calm period. The changes in grain sorting and longshore sediment transport serve as a clear evidence of the sediment migration that persevered between foreshore and nearshore regions. The Empirical Orthogonal Function (EOF) analysis and Canonical Correlation Analysis (CCA) were utilized to investigate the spatial and temporal linkages between beach and nearshore criterions. The outcome of the multivariate analysis unveiled that the seasonal variations in the wave climate tends to influence the bar-berm sediment transition that is discerned in the coast.

Ichnologic evidence of a Cambrian age in the southern Amazon Craton: Implications for the onset of the Western Gondwana history

NASA Astrophysics Data System (ADS)

Santos, Hudson P.; Mángano, M. Gabriela; Soares, Joelson L.; Nogueira, Afonso C. R.; Bandeira, José; Rudnitzki, Isaac D.

2017-07-01

Colonization of the infaunal ecospace by burrowing bilaterians is one of the most important behavioral innovations during the Ediacaran-Cambrian transition. The establishment of vertical burrows by suspension feeders in high-energy nearshore settings during Cambrian Age 2 is reflected by the appearance of the Skolithos Ichnofacies. For the first time, unquestionable vertical burrows typical of the Skolithos Ichnofacies, such as Skolithos linearis, Diplocraterion parallelum and Arenicolites isp., are recorded from nearshore siliciclastic deposits of the Raizama Formation, southeastern Amazon Craton, Brazil. Integration of ichnologic and sedimentologic datasets suggests that these trace fossils record colonization of high-energy and well-oxygenated nearshore sandy environments. Chronostratigraphically, the presence of these vertical burrows indicates an age not older than early Cambrian for the Raizama Formation, which traditionally has been regarded as Ediacaran. Therefore, the Raizama ichnofauna illustrates the advent of modern Phanerozoic ecology marked by the Agronomic Revolution. The discovery of the Skolithos Ichnofacies in these shallow-marine strata suggests possible connections between some central Western Gondwana basins.

Influence of PAHs among other coastal environmental variables on total and PAH-degrading bacterial communities.

PubMed

Sauret, Caroline; Tedetti, Marc; Guigue, Catherine; Dumas, Chloé; Lami, Raphaël; Pujo-Pay, Mireille; Conan, Pascal; Goutx, Madeleine; Ghiglione, Jean-François

2016-03-01

We evaluated the relative impact of anthropogenic polycyclic aromatic hydrocarbons (PAHs) among biogeochemical variables on total, metabolically active, and PAH bacterial communities in summer and winter in surface microlayer (SML) and subsurface seawaters (SSW) across short transects along the NW Mediterranean coast from three harbors, one wastewater effluent, and one nearshore observatory reference site. At both seasons, significant correlations were found between dissolved total PAH concentrations and PAH-degrading bacteria that formed a gradient from the shore to nearshore waters. Accumulation of PAH degraders was particularly high in the SML, where PAHs accumulated. Harbors and wastewater outfalls influenced drastically and in a different way the total and active bacterial community structure, but they only impacted the communities from the nearshore zone (<2 km from the shore). By using direct multivariate statistical analysis, we confirmed the significant effect of PAH concentrations on the spatial and temporal dynamic of total and active communities in this area, but this effect was putted in perspective by the importance of other biogeochemical variables.

Tsunami Inundation Mapping for the Upper East Coast of the United States

NASA Astrophysics Data System (ADS)

Tehranirad, B.; Kirby, J. T., Jr.; Callahan, J. A.; Shi, F.; Banihashemi, S.; Grilli, S. T.; Grilli, A. R.; Tajalli Bakhsh, T. S.; O'Reilly, C.

2014-12-01

We describe the modeling of tsunami inundation for the Upper US East Coast (USEC) from Ocean City, MD up to Nantucket, MA. and the development of inundation maps for use in emergency management and hazard analysis. Seven tsunami sources were used as initial conditions in order to develop inundation maps based on a Probable Maximum Tsunami approach. Of the seven, two coseismic sources were used; the first being a large earthquake in the Puerto Rico Trench, in the well-known Caribbean Subduction Zone, and the second, an earthquake close to the Azores Gibraltar plate boundary known as the source of the biggest tsunami recorded in the North Atlantic Basin. In addition, four Submarine Mass Failure (SMF) sources located at different locations on the edge of the shelf break were simulated. Finally, the Cumbre Vieja Volcanic (CVV) collapse, located in the Canary Islands, was studied. For this presentation, we discuss modeling results for nearshore tsunami propagation and onshore inundation. A fully nonlinear Boussinesq model (FUNWAVE-TVD) is used to capture the characteristics of tsunami propagation, both nearshore and inland. In addition to the inundation line as the main result of this work, other tsunami quantities such as inundation depth and maximum velocities will be discussed for the whole USEC area. Moreover, a discussion of most vulnerable areas to a possible tsunami in the USEC will be provided. For example, during the inundation simulation process, it was observed that coastal environments with barrier islands are among the hot spots to be significantly impacted by a tsunami. As a result, areas like western Long Island, NY and Atlantic City, NJ are some of the locations that will get extremely affected in case of a tsunami occurrence in the Atlantic Ocean. Finally, the differences between various tsunami sources modeled here will be presented. Although inundation lines for different sources usually follow a similar pattern, there are clear distinctions between the inundation depth and other tsunami features in different areas. Figure below shows the inundation depth for surrounding area of the Ocean City, MD. Figure (a) and (b) are the envelope inundation depth for SMF and coseismic sources. Figure (C) shows the inundation depth for CVV source, which clearly has the largest magnitude amongst the sources studied for this work.

Coastal groundwater/surface-water interactions: a Great Lakes case study

USGS Publications Warehouse

Neff, Brian P.; Haack, Sheridan K.; Rosenberry, Donald O.; Savino, Jacqueline F.; Lundstrom, Scott C.

2006-01-01

Key similarities exist between marine and Great Lakes coastal environments. Water and nutrient fluxes across lakebeds in the Great Lakes are influenced by seiche and wind set-up and set-down, analogous to tidal influence in marine settings. Groundwater/surface-water interactions also commonly involve a saline-fresh water interface, although in the Great-Lakes cases, it is groundwater that is commonly saline and surface water that is fresh. Evapotranspiration also affects nearshore hydrology in both settings. Interactions between groundwater and surface water have recently been identified as an important component of ecological processes in the Great Lakes. Water withdrawals and the reversal of the groundwater/surface water seepage gradient are also common to many coastal areas around the Great Lakes. As compared to surface water, regional groundwater that discharges to western Lake Erie from Michigan is highly mineralized. Studies conducted by the U.S. Geological Survey at Erie State Game Area in southeastern Michigan, describe groundwater flow dynamics and chemistry, shallow lake-water chemistry, and fish and invertebrate communities. Results presented here provide an overview of recent progress of ongoing interdisciplinary studies of Great Lakes nearshore systems and describe a conceptual model that identifies relations among geologic, hydrologic, chemical, and biological processes in the coastal habitats of Lake Erie. This conceptual model is based on analysis of hydraulic head in piezometers at the study site and chemical analysis of deep and shallow coastal groundwater.

The Effect of the Leeuwin Current on Offshore Surface Gravity Waves in Southwest Western Australia

NASA Astrophysics Data System (ADS)

Wandres, Moritz; Wijeratne, E. M. S.; Cosoli, Simone; Pattiaratchi, Charitha

2017-11-01

The knowledge of regional wave regimes is critical for coastal zone planning, protection, and management. In this study, the influence of the offshore current regime on surface gravity waves on the southwest Western Australian (SWWA) continental shelf was examined. This was achieved by coupling the three dimensional, free surface, terrain-following hydrodynamic Regional Ocean Modelling System (ROMS) and the third generation wave model Simulating WAves Nearshore (SWAN) using the Coupled Ocean-Atmosphere-WaveSediment Transport (COAWST) model. Different representative states of the Leeuwin Current (LC), a strong pole-ward flowing boundary current with a persistent eddy field along the SWWA shelf edge were simulated and used to investigate their influence on different large wave events. The coupled wave-current simulations were compared to wave only simulations, which represented scenarios in the absence of a background current field. Results showed that the LC and the eddy field significantly impact SWWA waves. Significant wave heights increased (decreased) when currents were opposing (aligning with) the incoming wave directions. During a fully developed LC system significant wave heights were altered by up to ±25% and wave directions by up to ±20°. The change in wave direction indicates that the LC may modify nearshore wave dynamics and consequently alter sediment patterns. Operational regional wave forecasts and hindcasts may give flawed predictions if wave-current interaction is not properly accounted for.

Nearshore Fish Distributions in an Alaskan Estuary in Relation to Stratification, Temperature and Salinity

NASA Astrophysics Data System (ADS)

Abookire, A. A.; Piatt, J. F.; Robards, M. D.

2000-07-01

Fish were sampled with beach seines and small-meshed beam trawls in nearshore (<1 km) and shallow (<25 m) habitats on the southern coast of Kachemak Bay, Cook Inlet, Alaska, from June to August, 1996-1998. Fish distributions among habitats were analysed for species composition, catch-per-unit-effort (CPUE) and frequency of occurrence. Two oceanographically distinct areas of Kachemak Bay were sampled and compared: the Outer Bay and the Inner Bay. Outer Kachemak Bay is exposed and receives oceanic, upwelled water from the Gulf of Alaska, whereas the Inner Bay is more estuarine. Thermohaline properties of bottom water in the Outer and Inner Bay were essentially the same, whereas the Inner Bay water-column was stratified with warmer, less saline waters near the surface. Distribution and abundance of pelagic schooling fish corresponded with area differences in stratification, temperature and salinity. The Inner Bay supported more species and higher densities of schooling and demersal fish than the Outer Bay. Schooling fish communities sampled by beach seine differed between the Outer and Inner Bays. Juvenile and adult Pacific sand lance ( Ammodytes hexapterus), Pacific herring ( Clupea harengus pallasi), osmerids (Osmeridae) and sculpins (Cottidae) were all more abundant in the Inner Bay. Gadids (Gadidae) were the only schooling fish taxa more abundant in the Outer Bay. Thermohaline characteristics of bottom water were similar throughout Kachemak Bay. Correspondingly, bottom fish communities were similar in all areas. Relative abundances (CPUE) were not significantly different between areas for any of the five demersal fish groups: flatfishes (Pleuronectidae), ronquils (Bathymasteridae), sculpins (Cottidae), gadids (Gadidae) and pricklebacks (Stichaeidae).

Nearshore fish distributions in an Alaskan estuary in relation to stratification, temperature, and salinity

USGS Publications Warehouse

Abookire, Alisa A.; Piatt, John F.; Robards, Martin D.

2000-01-01

Fish were sampled with beach seines and small-meshed beam trawls in nearshore ( < 1 km) and shallow ( < 25 m) habitats on the southern coast of Kachemak Bay, Cook Inlet, Alaska, from June to August, 1996-1998. Fish distributions among habitats were analysed for species composition, catch-per-unit-effort (CPUE) and frequency of occurrence. Two oceanographically distinct areas of Kachemak Bay were sampled and compared: the Outer Bay and the Inner Bay. Outer Kachemak Bay is exposed and receives oceanic, upwelled water from the Gulf of Alaska, whereas the Inner Bay is more estuarine. Thermohaline properties of bottom water in the Outer and Inner Bay were essentially the same, whereas the Inner Bay water-column was stratified with warmer, less saline waters near the surface. Distribution and abundance of pelagic schooling fish corresponded with area differences in stratification, temperature and salinity. The Inner Bay supported more species and higher densities of schooling and demersal fish than the Outer Bay. Schooling fish communities sampled by beach seine differed between the Outer and Inner Bays. Juvenile and adult Pacific sand lance (Ammodytes hexapterus), Pacific herring (Clupea harengus pallasi), osmerids (Osmeridae) and sculpins (Cottidae) were all more abundant in the Inner Bay. Gadids (Gadidae) were the only schooling fish taxa more abundant in the Outer Bay. Thermohaline characteristics of bottom water were similar throughout Kachemak Bay. Correspondingly, bottom fish communities were similar in all areas. Relative abundances (CPUE) were not significantly different between areas for any of the five demersal fish groups: flatfishes (Pleuronectidae), ronquils (Bathymasteridae), sculpins (Cottidae), gadids (Gadidae) and pricklebacks (Stichaeidae).

Population structure of Cladophora-borne Escherichia coli in nearshore water of Lake Michigan

USGS Publications Warehouse

Byappanahalli, M.N.; Whitman, R.L.; Shively, D.A.; Ferguson, J.; Ishii, S.; Sadowsky, M.J.

2007-01-01

We previously reported that the macrophytic green alga Cladophora harbors high densities (up to 106 colony-forming units/g dry weight) of the fecal indicator bacteria,Escherichia coli and enterococci, in shoreline waters of Lake Michigan. However, the population structure and genetic relatedness of Cladophora-borne indicator bacteria remain poorly understood. In this study, 835 E. coli isolates were collected fromCladophora tufts (mats) growing on rocks from a breakwater located within the Indiana Dunes National Lakeshore in northwest Indiana. The horizontal fluorophore enhanced rep-PCR (HFERP) DNA fingerprinting technique was used to determine the genetic relatedness of the isolates to each other and to those in a library of E. coli DNA fingerprints. While the E. coli isolates from Cladophora showed a high degree of genetic relatedness (⩾92% similarity), in most cases, however, the isolates were genetically distinct. The Shannon diversity index for the population was very high (5.39). Both spatial and temporal influences contributed to the genetic diversity. There was a strong association of isolate genotypes by location (79% and 80% for lake- and ditch-side samplings, respectively), and isolates collected from 2002 were distinctly different from those obtained in 2003. Cladophora-borne E. coli isolates represented a unique group, which was distinct from other E. coli isolates in the DNA fingerprint library tested. Taken together, these results indicate that E. coli strains associated with Cladophora may be a recurring source of indicator bacteria to the nearshore beach.

Storm impacts on a high energy sandy beach system, northwest Ireland: short (event) to long term (decadal) behaviour

NASA Astrophysics Data System (ADS)

Guisado-Pintado, Emilia; Jackson, Derek; Cooper, Andrew; O'Connor, Marianne

2017-04-01

Long-term monitoring of beach dynamics is an important element in risk prevention and management of both natural and human resources at the coast. The predicted intensification in storminess (frequency, duration and magnitude), partly associated with climate change, represents a pressing concern for coastal communities globally and has undoubtedly led to an improvement in available techniques and technologies for observation and analysis. Here we examine a high energy Atlantic beach system at Five Fingers strand (NW Ireland) to help understand hydrodynamic forcing on beach response under various wave energy scenarios. The system, which has been modally attuned to a large swell wave environment, periodically undergoes significant morphological changes over various spatial and temporal scales manifest in the development and movements of dynamic nearshore bars and a nearshore ebb-tide delta. A combination of field and laboratory techniques (GPS, Terrestrial Laser Scanning (TLS) Instrumentation, Drone surveys) implemented from the shoreface to the beach, captures the response and evolution of the system over the short (event), medium (weeks to months) and long-term (multiyear) timescale. Numerical modelling of nearshore wave hydrodynamics (using SWAN wave simulation model) helps understanding wave forcing across shoreface area and is ran under a number of iterative time intervals. Here, we investigate the role of infrequent and sometimes extreme events in the system to understand the importance of clustering of storminess and the occurrence of single high-magnitude storm events that perturb the inlet-beach system and thus induce key morphodynamic changes. Preliminary results show that ultimately the configuration of the ebb-tide channel influences the geomorphic response of the system. In the short term, a storm induced erosion of the shoreface is observed, which also appears to lead to changes in the ebb-tide channel, and ultimately the welding of a nearshore bar system at the northern part of the site over the medium to long term. We also observe that modal conditions favour intertidal beach recovery in the short and medium term, with a resulting southerly drift of sediment with an offshore return of sediment via the ebb-channel (multi-year response). This work demonstrates that coastal hazard analysis, approached at an appropriate site-specific scale and with suitable numerical modelling and field techniques, must include capturing data on nearshore forcing parameters that are driving shoreline response over various timescales. Understanding of these nearshore and intertidal morphodynamics is an important prelude to examining how a sandy shoreline behaves in response to high energy forcing. We advocate that morphodynamic self-adjustment of the beach system to a set of varying climatic conditions associated with increases in storminess, will have important implications for future coastline response.

The origin and distribution of subbottom sediments in southern Lake Champlain.

USGS Publications Warehouse

Freeman-Lynde, R. P.; Hutchinson, D.R.; Folger, D.W.; Wiley, B.H.; Hewett, M.J.

1980-01-01

3 units, correlatable with recent Lake Champlain, late-glacial marine Champlain Sea, and proglacial Lake Vermont sediments, have been identified from seismic reflection profiles and 8 piston cores. Lake Vermont deposits are nonfossiliferous and range from thin to absent nearshore and on bedrock highs to more than 126 m thick near Split Rock Point. Champlain Sea sediments contain marine foraminifers and ostracodes and are fairly uniform in thickness (20-30 m). Recent Lake Champlain sediments range in thickness from 0 to 25 m. Average sedimentation rates for Lake Vermont are considerably higher (4-8 cm/yr) than those for the Champlain Sea (0.8-1.2 cm/yr) and Lake Champlain (0.14-0.15 cm/yr). Bedrock, till, and deltaic and alluvial deposits were also identified.- from Authors

Coastal circulation and water-column properties in the National Park of American Samoa, February–July 2015

USGS Publications Warehouse

Storlazzi, Curt; Cheriton, Olivia; Rosenberger, Kurt; Logan, Joshua; Clark, Timothy B.

2017-06-06

There is little information on the oceanography in the National Park of American Samoa (NPSA). The transport pathways for potentially harmful constituents of land-derived runoff, as well as larvae and other planktonic organisms, are driven by nearshore circulation patterns. To evaluate the processes affecting coral reef ecosystem health, it is first necessary to understand the oceanographic processes driving nearshore circulation, residence times, exposure rates, and transport pathways. Information on how the NPSA’s natural resources may be affected by anthropogenic sources of pollution, sediment runoff, larval transport, or modifications to the marine protected areas is critical to NPSA resource managers for understanding and ultimately managing coastal and marine resources. To address this need, U.S. Geological Survey and U.S. National Park Service researchers conducted a collaborative study in 2015 to determine coastal circulation patterns and water-column properties along north-central Tutuila, American Samoa, in an area focused on NPSA’s Tutuila Unit and its coral reef ecosystem. The continuous measurements of waves, currents, tides, and water-column properties from these instrument deployments over 150 days, coupled with available meteorological measurements of wind and rainfall, provide information on nearshore circulation and the variability in these hydrodynamic properties for NPSA’s Tutuila Unit. In general, circulation was strongly driven by regional winds at longer (greater than day) timescales and by tides at shorter (less than day) timescales. Flows were primarily directed along shore, with current speeds faster offshore to the north and slower closer to shore, especially in embayments. Water-column properties exhibit strong seasonality coupled to the shift from non-trade wind season to trade wind season. During the non-trade wind season that was characterized by variable winds and larger waves in the NPSA, waters were warmer, slightly more saline, relatively less optically clear, and more stratified. When winds shifted to a more consistent trade wind pattern in the austral fall, the waters cooled and became less stratified because of decreased insolation. There are consistent spatial patterns in water column characteristics—Waters were warmer and less saline near the surface and closer to shore, especially in embayments, which tended to be more turbid, less clear, and characterized by higher chlorophyll than waters offshore. Water residence times were shorter farther offshore and longer closer to shore and in embayments, but varied spatially because of different forcing. Warmer, lower salinity, higher chlorophyll, and more turbid waters in embayments tend to reside in those locations for much greater durations, resulting in greater exposure of embayment ecosystems to those waters. This is in contrast with waters farther offshore, where the combination of shorter residence times and cooler, higher salinity water results in less exposure to land runoff. Understanding coastal circulation patterns and water-column properties in NPSA’s waters along north-central Tutuila may help to better understand how meteorological and oceanographic processes, at the regional and local scale, affect coral reef health and sustainability in this region.

Ordovician conodonts and stratigraphy of the ST. Peter sandstone and glen wood shale, central United States

USGS Publications Warehouse

Witzke, B.J.; Metzger, R.A.

2005-01-01

The age of the St. Peter Sandstone in the central and northern Midcontinent has long been considered equivocal because of the general absence of biostratigraphically useful fossils. Conodonts recovered from the St. Peter Sandstone in Iowa, Minnesota, Nebraska, and Kansas for this study help place some age constraints on this renowned formation in its northern and western extent. Faunas from the lower St. Peter include Phragmodus flexuosus, Cahabagnathus sp., and Leptochirognathus sp., and a late Whiterockian (Chazyan) correlation is indicated. Juvenile or immature elements of P. flexuosus from these collections show morphologies trending toward P. cognitus and P. inflexus, and paedomorphic derivation of these latter species is proposed. Diverse assemblages of hyaline forms also occur in the St. Peter strata (Erismodus spp., Erraticodon sp., Curtognathus sp., Coleodus sp., Archeognathus sp., Stereoconus sp., others) along with various albid elements (Plectodina sp., Eoplacognathus sp., others). The overlying Glenwood Shale contains abundant conodonts dominated by Phragmodus cognitus, Erismodus sp., and Chirognathus duodactylus, and the fauna is interpreted as an early Mohawkian (Blackriveran) association. Certain thin shale units in the St. Peter-Glenwood succession represent condensed intervals, in part reflected by their exceptionally high conodont abundances. Some organic-rich phosphatic shale units in the lower St. Peter of western Iowa have produced equivalent yields of tens of thousands of conodonts per kilogram, and many Glenwood Shale samples yield thousands of conodonts per kilogram. Previous depositional models have proposed that the St. Peter is primarily a succession of littoral and nearshore facies forming a broadly diachronous transgressive sheet sand. However, broad-scale diachroneity cannot be demonstrated with available biostratigraphic control. The recognition of condensed marine shale units, phosphorites, ironstones, and pyritic hardgrounds in the western facies tract of the St. Peter Sandstone has necessitated a re-evaluation of previous regional models of St. Peter deposition. The St. Peter is interpreted to be a composite stratigraphic interval deposited during a succession of transgressive-regressive sedimentary cycles. Transgressive episodes in some cycles were marked by offshore sediment condensation or starvation within a stratified seaway.

Habitat use by fishes of Lake Superior. II. Consequences of diel habitat use for habitat linkages and habitat coupling in nearshore and offshore waters

USGS Publications Warehouse

Gorman, Owen T.; Yule, Daniel L.; Stockwell, Jason D.

2012-01-01

Diel migration patterns of fishes in nearshore (15–80 m depth) and offshore (>80 m) waters of Lake Superior were examined to assess the potential for diel migration to link benthic and pelagic, and nearshore and offshore habitats. In our companion article, we described three types of diel migration: diel vertical migration (DVM), diel bank migration (DBM), and no diel migration. DVM was expressed by fishes migrating from benthopelagic to pelagic positions and DBM was expressed by fishes migrating horizontally from deep to shallow waters at night. Fishes not exhibiting diel migration typically showed increased activity by moving from benthic to benthopelagic positions within demersal habitat. The distribution and biomass of fishes in Lake Superior was characterized by examining 704 bottom trawl samples collected between 2001 and 2008 from four depth zones: ≤40, 41–80, 81–160, and >160 m. Diel migration behaviors of fishes described in our companion article were applied to estimates of areal biomass (kg ha−1) for each species by depth zone. The relative strength of diel migrations were assessed by applying lake area to areal biomass estimates for each species by depth zone to yield estimates of lake-wide biomass (metric tonnes). Overall, species expressing DVM accounted for 83%, DBM 6%, and non-migration 11% of the total lake-wide community biomass. In nearshore waters, species expressing DVM represented 74% of the biomass, DBM 25%, and non-migration 1%. In offshore waters, species expressing DVM represented 85%, DBM 1%, and non-migration 14% of the biomass. Of species expressing DVM, 83% of total biomass occurred in offshore waters. Similarly, 97% of biomass of non-migrators occurred in offshore waters while 83% of biomass of species expressing DBM occurred in nearshore waters. A high correlation (R2 = 0.996) between lake area and community biomass by depth zone resulted in 81% of the lake-wide biomass occurring in offshore waters. Accentuating this nearshore-offshore trend was one of increasing estimated total areal biomass of the fish community with depth zone, which ranged from 13.71 kg ha−1 at depths ≤40 m to 18.81 kg ha−1 at depths >160 m, emphasizing the importance of the offshore fish community to the lake ecosystem. The prevalence of diel migration expressed by Lake Superior fishes increases the potential of fish to link benthic and pelagic and shallow and deepwater habitats. These linkages enhance the potential for habitat coupling, a condition where habitats become interconnected and interdependent through transfers of energy and nutrients. Habitat coupling facilitates energy and nutrient flow through a lake ecosystem, thereby increasing productivity, especially in large lakes where benthic and pelagic, and nearshore and offshore habitats are often well separated. We propose that the application of biomass estimates to patterns of diel migration in fishes can serve as a useful metric for assessing the potential for habitat linkages and habitat coupling in lake ecosystems, and provide an important indicator of ecosystem health and function. The decline of native Lake Trout and ciscoes and recent declines in exotic Alewife and Rainbow Smelt populations in other Great Lakes have likely reduced the capacity for benthic-pelagic coupling in these systems compared to Lake Superior. We recommend comparing the levels and temporal changes in diel migration in other Great Lakes as a means to assess changes in the relative health and function of these ecosystems.

Widespread kelp-derived carbon in pelagic and benthic nearshore fishes

USGS Publications Warehouse

von Biela, Vanessa R.; Newsome, Seth D.; Bodkin, James L.; Kruse, Gordon H.; Zimmerman, Christian E.

2016-01-01

Kelp forests provide habitat for diverse and abundant fish assemblages, but the extent to which kelp provides a source of energy to fish and other predators is unclear. To examine the use of kelp-derived energy by fishes we estimated the contribution of kelp- and phytoplankton-derived carbon using carbon (δ13C) and nitrogen (δ15N) isotopes measured in muscle tissue. Benthic-foraging kelp greenling (Hexagrammos decagrammus) and pelagic-foraging black rockfish (Sebastes melanops) were collected at eight sites spanning ∼35 to 60°N from the California Current (upwelling) to Alaska Coastal Current (downwelling) in the northeast Pacific Ocean. Muscle δ13C values were expected to be higher for fish tissue primarily derived from kelp, a benthic macroalgae, and lower for tissue primarily derived from phytoplankton, pelagic microalgae. Muscle δ13C values were higher in benthic-feeding kelp greenling than in pelagic-feeding black rockfish at seven of eight sites, indicating more kelp-derived carbon in greenling as expected. Estimates of kelp carbon contributions ranged from 36 to 89% in kelp greenling and 32 to 65% in black rockfish using carbon isotope mixing models. Isotopic evidence suggests that these two nearshore fishes routinely derive energy from kelp and phytoplankton, across coastal upwelling and downwelling systems. Thus, the foraging mode of nearshore predators has a small influence on their ultimate energy source as energy produced by benthic macroalgae and pelagic microalgae were incorporated in fish tissue regardless of feeding mode and suggest strong and widespread benthic-pelagic coupling. Widespread kelp contributions to benthic- and pelagic-feeding fishes suggests that kelp energy provides a benefit to nearshore fishes and highlights the potential for kelp and fish production to be linked.

Temporal-spatial variations and influencing factors of nitrogen in the shallow groundwater of the nearshore vegetable field of Erhai Lake, China.

PubMed

Chen, Anqiang; Lei, Baokun; Hu, Wanli; Wang, Hongyuan; Zhai, Limei; Mao, Yanting; Fu, Bin; Zhang, Dan

2018-02-01

Nitrogen export from the nearshore vegetable field of Erhai Lake seriously threatens the water quality of Erhai Lake, which is the second largest highland freshwater lake in Yunnan Province, China. Among the nitrogen flows into Erhai Lake, shallow groundwater migration is a major pathway. The nitrogen variation and influencing factors in the shallow groundwater of the nearshore vegetable field of Erhai Lake are not well documented. A 2-year field experiment was conducted to determine the concentrations of nitrogen species in the shallow groundwater and their influencing factors in the nearshore vegetable field of Erhai Lake. The results showed that concentrations of TN, NO 3 - -N, and NO 2 - -N gradually increased with increasing elevation and distance from Erhai Lake, but the opposite was observed for NH 4 + -N in the shallow groundwater. The concentrations of nitrogen species in the rainy season were greater than those in the dry season. NO 3 - -N accounted for more than 79% of total nitrogen in shallow groundwater. Redundancy analysis showed that more than 70% of the temporal and spatial variations of nitrogen concentrations in the shallow groundwater were explained by shallow groundwater depth, and only approximately 10% of variation was explained by the factors of soil porosity, silt clay content of soil, and NH 4 + -N and NO 3 - -N concentrations of soil (p < 0.05). The shallow groundwater depth had more notable effects on nitrogen concentrations in the shallow groundwater than other factors. This result will strongly support the need for further research regarding the management practices for reducing nitrogen concentrations in shallow groundwater.

Alongshore Variation in the Depth of Activation: Implications of Oil Residence Time

NASA Astrophysics Data System (ADS)

Flores, P.; Houser, C.

2016-12-01

In 2010 the Deepwater Horizon Oil Spill released approximately 5 million barrels of oil into the Gulf of Mexico just as the nearshore and beach profile were recovering from winter storms. As a consequence, oil mats and tar balls were trapped at depth within the beach and nearshore profile. Excavation of this buried oil during subsequent storms creates the potential for the contamination of adjacent beaches and the degradation of marine ecosystems, which can in turn negatively impact local economies that depend on fisheries and tourism. The potential for oil burial and persistence is dependent on four things: the physio-chemical nature of the oil as it reaches the nearshore environment, the pre-existing morphology of the beach and nearshore, and the evolution of that morphology after the oil is deposited. The depth at which the oil is buried is also dependent on the beach profile during the time of the spill. The purpose of this study is to characterize the alongshore variation in depth of activation on a Deepwater Horizon impacted section of Pensacola Beach, Florida with regards to the implications of oil residence time. Ground- Penetrating Radar (GPR) surveys were conducted along two parallel 1-km transects adjacent to the swash zone and the dune. Additional cross- shore transects were completed every 150 m from the base of the dune to the top of the swash zone. Sediments cores were taken at the crossing points of the alongshore and cross-shore transects, to calibrate the GPR surveys and complete an elemental analysis for the identification of storm layers. The cores were also analyzed for the presence of buried oil.

Detailed Characterization of Nearshore Processes During NCEX

NASA Astrophysics Data System (ADS)

Holland, K.; Kaihatu, J. M.; Plant, N.

2004-12-01

Recent technology advances have allowed the coupling of remote sensing methods with advanced wave and circulation models to yield detailed characterizations of nearshore processes. This methodology was demonstrated as part of the Nearshore Canyon EXperiment (NCEX) in La Jolla, CA during Fall 2003. An array of high-resolution, color digital cameras was installed to monitor an alongshore distance of nearly 2 km out to depths of 25 m. This digital imagery was analyzed over the three-month period through an automated process to produce hourly estimates of wave period, wave direction, breaker height, shoreline position, sandbar location, and bathymetry at numerous locations during daylight hours. Interesting wave propagation patterns in the vicinity of the canyons were observed. In addition, directional wave spectra and swash / surf flow velocities were estimated using more computationally intensive methods. These measurements were used to provide forcing and boundary conditions for the Delft3D wave and circulation model, giving additional estimates of nearshore processes such as dissipation and rip currents. An optimal approach for coupling these remotely sensed observations to the numerical model was selected to yield accurate, but also timely characterizations. This involved assimilation of directional spectral estimates near the offshore boundary to mimic forcing conditions achieved under traditional approaches involving nested domains. Measurements of breaker heights and flow speeds were also used to adaptively tune model parameters to provide enhanced accuracy. Comparisons of model predictions and video observations show significant correlation. As compared to nesting within larger-scale and coarser resolution models, the advantages of providing boundary conditions data using remote sensing is much improved resolution and fidelity. For example, rip current development was both modeled and observed. These results indicate that this approach to data-model coupling is tenable and may be useful in near-real-time characterizations required by many applied scenarios.

Understanding Coral's Short-term Adaptive Ability to Changing Environment

NASA Astrophysics Data System (ADS)

Tisthammer, K.; Richmond, R. H.

2016-02-01

Corals in Maunalua Bay, Hawaii are under chronic pressures from sedimentation and terrestrial runoffs containing multiple pollutants as a result of large scale urbanization that has taken place in the last 100 years. However, some individual corals thrive despite the prolonged exposure to these environmental stressors, which suggests that these individuals may have adapted to withstand such stressors. A recent survey showed that the lobe coral Porites lobata from the `high-stress' nearshore site had an elevated level of stress ixnduced proteins, compared to those from the `low-stress,' less polluted offshore site. To understand the genetic basis for the observed differential stress responses between the nearshore and offshore P. lobata populations, an analysis of the lineage-scale population genetic structure, as well as a reciprocal transplant experiment were conducted. The result of the genetic analysis revealed a clear genetic differentiation between P. lobata from the nearshore site and the offshore site. Following the 30- day reciprocal transplant experiment, protein expression profiles and other stress-related physiological characteristics were compared between the two populations. The experimental results suggest that the nearshore genotype can cope better with sedimentation/pollutants than the offshore genotype. This indicates that the observed genetic differentiation is due to selection for tolerance to these environmental stressors. Understanding the little-known, linage-scale genetic variation in corals offers a critical insight into their short-term adaptive ability, which is indispensable for protecting corals from impending environmental and climate change. The results of this study also offer a valuable tool for resource managers to make effective decisions on coral reef conservation, such as designing marine protected areas that incorporate and maintain such genetic diversity, and establishing acceptable pollution run-off levels.

Ocean acidification changes the structure of an Antarctic coastal protistan community

NASA Astrophysics Data System (ADS)

Hancock, Alyce M.; Davidson, Andrew T.; McKinlay, John; McMinn, Andrew; Schulz, Kai G.; van den Enden, Rick L.

2018-04-01

Antarctic near-shore waters are amongst the most sensitive in the world to ocean acidification. Microbes occupying these waters are critical drivers of ecosystem productivity, elemental cycling and ocean biogeochemistry, yet little is known about their sensitivity to ocean acidification. A six-level, dose-response experiment was conducted using 650 L incubation tanks (minicosms) adjusted to a gradient in fugacity of carbon dioxide (fCO2) from 343 to 1641 µatm. The six minicosms were filled with near-shore water from Prydz Bay, East Antarctica, and the protistan composition and abundance was determined by microscopy during 18 days of incubation. No CO2-related change in the protistan community composition was observed during the initial 8 day acclimation period under low light. Thereafter, the response of both autotrophic and heterotrophic protists to fCO2 was species-specific. The response of diatoms was mainly cell size related; microplanktonic diatoms ( > 20 µm) increased in abundance with low to moderate fCO2 (343-634 µatm) but decreased at fCO2 ≥ 953 µatm. Similarly, the abundance of Phaeocystis antarctica increased with increasing fCO2 peaking at 634 µatm. Above this threshold the abundance of micro-sized diatoms and P. antarctica fell dramatically, and nanoplanktonic diatoms ( ≤ 20 µm) dominated, therefore culminating in a significant change in the protistan community composition. Comparisons of these results with previous experiments conducted at this site show that the fCO2 thresholds are similar, despite seasonal and interannual differences in the physical and biotic environment. This suggests that near-shore microbial communities are likely to change significantly near the end of this century if anthropogenic CO2 release continues unabated, with profound ramifications for near-shore Antarctic ecosystem food webs and biogeochemical cycling.

Wave-induced mass transport affects daily Escherichia coli fluctuations in nearshore water.

PubMed

Ge, Zhongfu; Whitman, Richard L; Nevers, Meredith B; Phanikumar, Mantha S

2012-02-21

Characterization of diel variability of fecal indicator bacteria concentration in nearshore waters is of particular importance for development of water sampling standards and protection of public health. Significant nighttime increase in Escherichia coli (E. coli) concentration in beach water, previously observed at marine sites, has also been identified in summer 2000 from fixed locations in waist- and knee-deep waters at Chicago 63rd Street Beach, an embayed, tideless, freshwater beach with low currents at night (approximately 0.015 m s(-1)). A theoretical model using wave-induced mass transport velocity for advection was developed to assess the contribution of surface waves to the observed nighttime E. coli replenishment in the nearshore water. Using average wave conditions for the summer season of year 2000, the model predicted an amount of E. coli transported from water of intermediate depth, where sediment resuspension occurred intermittently, that would be sufficient to have elevated E. coli concentration in the surf and swash zones as observed. The nighttime replenishment of E. coli in the surf and swash zones revealed here is an important phase in the cycle of diel variations of E. coli concentration in nearshore water. According to previous findings in Ge et al. (Environ. Sci. Technol. 2010, 44, 6731-6737), enhanced current circulation in the embayment during the day tends to displace and deposit material offshore, which partially sets up the system by the early evening for a new period of nighttime onshore movement. This wave-induced mass transport effect, although facilitating a significant base supply of material shoreward, can be perturbed or significantly influenced by high currents (orders of magnitude larger than a typical wave-induced mass transport velocity), current-induced turbulence, and tidal forcing.

A conceptual framework for Lake Michigan coastal/nearshore ecosystems, with application to Lake Michigan Lakewide Management Plan (LaMP) objectives

USGS Publications Warehouse

Seelbach, Paul W.; Fogarty, Lisa R.; Bunnell, David Bo; Haack, Sheridan K.; Rogers, Mark W.

2013-01-01

The Lakewide Management Plans (LaMPs) within the Great Lakes region are examples of broad-scale, collaborative resource-management efforts that require a sound ecosystems approach. Yet, the LaMP process is lacking a holistic framework that allows these individual actions to be planned and understood within the broader context of the Great Lakes ecosystem. In this paper we (1) introduce a conceptual framework that unifies ideas and language among Great Lakes managers and scientists, whose focus areas range from tributary watersheds to open-lake waters, and (2) illustrate how the framework can be used to outline the geomorphic, hydrologic biological, and societal processes that underlie several goals of the Lake Michigan LaMP, thus providing a holistic and fairly comprehensive roadmap for tackling these challenges. For each selected goal, we developed a matrix that identifies the key ecosystem processes within the cell for each lake zone and each discipline; we then provide one example where a process is poorly understood and a second where a process is understood, but its impact or importance is unclear. Implicit in these objectives was our intention to highlight the importance of the Great Lakes coastal/nearshore zone. Although the coastal/nearshore zone is the important linkage zone between the watershed and open-lake zones—and is the zone where most LaMP issues are focused--scientists and managers have a relatively poor understanding of how the coastal/nearshore zone functions. We envision follow-up steps including (1) collaborative development of a more detailed and more complete conceptual model of how (and where) identified processes are thought to function, and (2) a subsequent gap analysis of science and monitoring priorities.

Widespread kelp-derived carbon in pelagic and benthic nearshore fishes suggested by stable isotope analysis

NASA Astrophysics Data System (ADS)

von Biela, Vanessa R.; Newsome, Seth D.; Bodkin, James L.; Kruse, Gordon H.; Zimmerman, Christian E.

2016-11-01

Kelp forests provide habitat for diverse and abundant fish assemblages, but the extent to which kelp provides a source of energy to fish and other predators is unclear. To examine the use of kelp-derived energy by fishes we estimated the contribution of kelp- and phytoplankton-derived carbon using carbon (δ13C) and nitrogen (δ15N) isotopes measured in muscle tissue. Benthic-foraging kelp greenling (Hexagrammos decagrammus) and pelagic-foraging black rockfish (Sebastes melanops) were collected at eight sites spanning ∼35 to 60°N from the California Current (upwelling) to Alaska Coastal Current (downwelling) in the northeast Pacific Ocean. Muscle δ13C values were expected to be higher for fish tissue primarily derived from kelp, a benthic macroalgae, and lower for tissue primarily derived from phytoplankton, pelagic microalgae. Muscle δ13C values were higher in benthic-feeding kelp greenling than in pelagic-feeding black rockfish at seven of eight sites, indicating more kelp-derived carbon in greenling as expected. Estimates of kelp carbon contributions ranged from 36 to 89% in kelp greenling and 32 to 65% in black rockfish using carbon isotope mixing models. Isotopic evidence suggests that these two nearshore fishes routinely derive energy from kelp and phytoplankton, across coastal upwelling and downwelling systems. Thus, the foraging mode of nearshore predators has a small influence on their ultimate energy source as energy produced by benthic macroalgae and pelagic microalgae were incorporated in fish tissue regardless of feeding mode and suggest strong and widespread benthic-pelagic coupling. Widespread kelp contributions to benthic- and pelagic-feeding fishes suggests that kelp energy provides a benefit to nearshore fishes and highlights the potential for kelp and fish production to be linked.

Sources of Nutrients to Nearshore Areas of a Eutrophic Estuary: Implications for Nutrient-Enhanced Acidification in Puget Sound

NASA Astrophysics Data System (ADS)

Pacella, S. R.

2016-02-01

Ocean acidification has recently been highlighted as a major stressor for coastal organisms. Further work is needed to assess the role of anthropogenic nutrient additions in eutrophied systems on local biological processes, and how this interacts with CO2 emission-driven acidification. This study sought to distinguish changes in pH caused by natural versus anthropogenically affected processes. We quantified the variability in water column pH attributable to primary production and respiration fueled by anthropogenically derived nitrogen in a shallow nearshore area. Two study sites were located in shallow subtidal areas of the Snohomish River estuary, a eutrophic system located in central Puget Sound, Washington. These sites were chosen due to the presence of heavy agricultural activity, urbanized areas with associated waste water treatment, as well as influence from deep, high CO2 marine waters transported through the Strait of Juan de Fuca and upwelled into the area during spring and summer. Data was collected from July-December 2015 utilizing continuous moorings and discrete water column sampling. Analysis of stable isotopes, δ15N, δ18O-NO3, δ15N-NH4, was used to estimate the relative contributions of anthropogenic versus upwelled marine nitrogen sources. Continuous monitoring of pH, dissolved oxygen, temperature, and salinity was conducted at both study sites to link changes in nutrient source and availability with changes in pH. We predicted that isotope data would indicate greater contributions of nitrogen from agriculture and wastewater rather than upwelling in the shallow, nearshore study sites. This study seeks to distinguish the relative magnitude of pH change stimulated by anthropogenic versus natural sources of nitrogen to inform public policy decisions in critically important nearshore ecosystems.

Wave-induced mass transport affects daily Escherichia coli fluctuations in nearshore water

USGS Publications Warehouse

Ge, Zhongfu; Whitman, Richard L.; Nevers, Meredith B.; Phanikumar, Mantha S.

2012-01-01

Characterization of diel variability of fecal indicator bacteria concentration in nearshore waters is of particular importance for development of water sampling standards and protection of public health. Significant nighttime increase in Escherichia coli (E. coli) concentration in beach water, previously observed at marine sites, has also been identified in summer 2000 from fixed locations in waist- and knee-deep waters at Chicago 63rd Street Beach, an embayed, tideless, freshwater beach with low currents at night (approximately 0.015 m s–1). A theoretical model using wave-induced mass transport velocity for advection was developed to assess the contribution of surface waves to the observed nighttime E. coli replenishment in the nearshore water. Using average wave conditions for the summer season of year 2000, the model predicted an amount of E. coli transported from water of intermediate depth, where sediment resuspension occurred intermittently, that would be sufficient to have elevated E. coli concentration in the surf and swash zones as observed. The nighttime replenishment of E. coli in the surf and swash zones revealed here is an important phase in the cycle of diel variations of E. coli concentration in nearshore water. According to previous findings in Ge et al. (Environ. Sci. Technol. 2010, 44, 6731–6737), enhanced current circulation in the embayment during the day tends to displace and deposit material offshore, which partially sets up the system by the early evening for a new period of nighttime onshore movement. This wave-induced mass transport effect, although facilitating a significant base supply of material shoreward, can be perturbed or significantly influenced by high currents (orders of magnitude larger than a typical wave-induced mass transport velocity), current-induced turbulence, and tidal forcing.

Dynamics of fecal indicator bacteria, bacterial pathogen genes, and organic wastewater contaminants in the Little Calumet River: Portage Burns Waterway, Indiana

USGS Publications Warehouse

Haack, Sheridan K.; Duris, Joseph W.

2013-01-01

Little information exists on the co-occurrence of fecal indicator bacteria (FIB), bacterial pathogens, and organic wastewater-associated chemicals (OWCs) within Great Lakes tributaries. Fifteen watershed sites and one beach site adjacent to the Little Calumet River–Portage Burns Waterway (LCRPBW) on Lake Michigan were tested on four dates for pH, dissolved oxygen, specific conductance, chloride, color, ammonia- and nitrate-nitrogen, soluble phosphorus, sulfate, turbidity, and atrazine; for concentrations of FIB; and for genes indicating the presence of human-pathogenic enterococci (ENT) and of Shiga-toxin producing Escherichia coli (EC) from various animal sources. Nineteen samples were also tested for 60 OWCs. Half of the watershed samples met EC recreational water quality standards; none met ENT standards. Human-wastewater-associated OWC detections were correlated with human-influence indicators such as population/km2, chloride concentrations, and the presence of WWTP effluents, but EC and ENT concentrations were not. Bacterial pathogen genes indicated rural human and several potential animal sources. OWCs of human or ecosystem health concern (musk fragrances AHTN and HHCB, alkylphenols, carbamazepine) and 3 bacterial pathogen genes were detected at the mouth of the LCRPBW, but no such OWCs and only 1 pathogen gene were detected at the beach. The LCRPBW has significant potential to deliver FIB, potential bacterial pathogens, and OWCs of human or ecosystem health concern to the nearshore of Lake Michigan, under conditions enhancing nearshore transport of the river plume. Nearshore mixing of lake and river water, and the lack of relationship between OWCs and FIB or pathogen genes, pose numerous challenges for watershed and nearshore assessment and remediation.

Paleontology and geochronology of the Long Beach core sites and monitoring wells, Long Beach, California

USGS Publications Warehouse

McDougall, Kristin; Hillhouse, John; Powell, Charles; Mahan, Shannon; Wan, Elmira; Sarna-Wojcicki, Andrei M.

2012-01-01

The U.S. Geological Survey's Focus on Quaternary Stratigraphy in Los Angeles (FOQUS-LA) project was a cooperative coring program between Federal, State, and local agencies. It was designed to provide a better understanding of earthquake potentials and to develop a stratigraphic model of the western Los Angeles Basin in California. The biostratigraphic, geochronologic, and paleoecologic analyses of eight wells drilled during the FOQUS-LA project are presented. These analyses are based on microfossils (benthic and planktic foraminifers), macrofossils, paleomagnetic stratigraphy, optically stimulated luminescence, thermoluminescence, radiocarbon dating, and tephrochronology. A geochronologic framework (incorporating paleomagnetism, luminescence, and tephrochronology) was used to calibrate the sequence stratigraphic units in the FOQUS-LA wells and also was used to calibrate the ages of the microfossil stage and zonal boundaries. The results of this study show that (1) the offshore California margin zones can be used in a nearshore setting, and (2) the California margin zonal scheme refines the chronostratigraphic resolution of the benthic foraminiferal biostratigraphic framework for the Pacific Coast. Benthic foraminiferal stages are modified by the recognition of an early Hallian substage, which is a faunal change recognized throughout the Los Angeles Basin. Although no detailed macrofossil zonations exist for the Quaternary of southern California, several species, whose distribution is regulated by the climatic conditions, are useful as secondary marker species in the shallower water deposits of the Los Angeles Basin.

Phylogenetics, systematics, paleoecology, and evolution of the trilobite genera Paladin and Kaskia from the United States

USGS Publications Warehouse

Brezinski, D.K.

2008-01-01

Late Mississippian and earliest Pennsylvanian trilobite faunas of North America are dominated by the Paladin and Kaskia clades. Phylogenetic analysis of middle Carboniferous species of these clades demonstrates the close ancestral relationship between these groups. The Kaskia clade consists of eight species: K. chesterensis Weller, 1936, K. osagensis (Cisne, 1967), K. longispina (Strong, 1872), K. wilsoni (Walter, 1924), K. genevievensis (Walter, 1924), K. rosei (Cisne, 1967), K. gersnai n. sp., and K. rollinsi n. sp. Kaskia Weller, 1936 ranges from late Osagean to middle Chesterian (early Visean-early Serpukhovian) and is restricted to cyclothemic shelf and nearshore deposits. Species of Kaskia appear to have evolved in areas of shallow water and high environmental stress. The Paladin clade consists of 12 species including previously named species P. morrowensis (Mather, 1915), P. girtyianus Hahn and Hahn, 1970, P. rarus Whittington, 1954, P. helmsensis Whittington, 1954, and P. moorei (Branson, 1937). New species belonging to this clade are Paladin moorefieldensis n. sp., P. pleisiomorphus n. sp., P. imoensis n. sp., P. mangeri n. sp., and P. wapanukaensis n. sp. This group ranges from the early Chesterian to early Morrowan (late Viseanlate Bashkirian). Species of Paladin appear to be confined to outer shelf shelf-edge and off-shelf facies where presumably deeper water environments existed. This is manifested in their paleogeographic distribution, which is paleoenvironmentally controlled. Copyright ?? 2008, The Paleontological Society.

Eolian deposits in the Neoproterozoic Big Bear Group, San Bernardino Mountains, California, USA

NASA Astrophysics Data System (ADS)

Stewart, John H.

2005-12-01

Strata interpreted to be eolian are recognized in the Neoproterozoic Big Bear Group in the San Bernardino Mountains of southern California, USA. The strata consist of medium- to large-scale (30 cm to > 6 m) cross-stratified quartzite considered to be eolian dune deposits and interstratified thinly laminated quartzite that are problematically interpreted as either eolian translatent climbing ripple laminae, or as tidal-flat deposits. High index ripples and adhesion structures considered to be eolian are associated with the thinly laminated and cross-stratified strata. The eolian strata are in a succession that is characterized by flaser bedding, aqueous ripple marks, mudcracks, and interstratified small-scale cross-strata that are suggestive of a tidal environment containing local fluvial deposits. The eolian strata may have formed in a near-shore environment inland of a tidal flat. The Neoproterozoic Big Bear Group is unusual in the western United States and may represent a remnant of strata that were originally more widespread and part of the hypothetical Neoproterozoic supercontinent of Rodinia. The Big Bear Group perhaps is preserved only in blocks that were downdropped along Neoproterozoic extensional faults. The eolian deposits of the Big Bear Group may have been deposited during arid conditions that preceded worldwide glacial events in the late Neoproterozoic. Possibly similar pre-glacial arid events are recognized in northern Mexico, northeast Washington, Australia, and northwest Canada.

AN INNOVATIVE APPROACH FOR CONSTRUCTING AN IN-SITU BARRIER FOR STRONTIUM-90 AT THE HANFORD SITE WASHINGTON

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

FABRE RJ

2008-12-08

Efforts to reduce the flux of Sr-90 to the Columbia River from Hanford Site 100-N Area past-practice liquid waste disposal sites have been underway since the early 1990s. Termination of all liquid discharges to the ground in 1993 was a major step toward meeting this goal. However, Sr-90 adsorbed on aquifer solids beneath liquid waste disposal sites and extending beneath the near-shore riverbed remains a continuing contaminant source to groundwater and the Columbia River. The initial pump-and-treat system proved to be ineffective as a long-term solution because of the geochemical characteristics of Sr-90. Following an evaluation of potential Sr-90 treatmentmore » technologies and their applicability under 100-NR-2 Operable Unit hydrogeologic conditions, the U.S. Department of Energy and the Washington State Department of Ecology agreed to evaluate apatite sequestration as the primary remedial technology, combined with a secondary polishing step utilizing phytoextraction if necessary. Aqueous injection was initiated in July 2005 to assess the efficacy of in-situ apatite along the 100 m of shoreline where Sr-90 concentrations are highest. The remedial technology is being developed by Pacific Northwest National Laboratory. CH2M Hill Plateau Remediation Company is implementing this technology in the field with support from PNNL.« less

An Innovative Approach for Constructing an In-Situ Barrier for Strontium-90 at the Hanford Site, Washington - 9325

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

Thompson, K. M.; Fabre, Russel J.; Vermeul, Vincent R.

2008-12-10

Efforts to reduce the flux of Sr-90 to the Columbia River from Hanford Site 100-N Area past-practice liquid waste disposal sites have been underway since the early 1990s. Termination of all liquid discharges to the ground in 1993 was a major step toward meeting this goal. However, Sr 90 adsorbed on aquifer solids beneath liquid waste disposal sites and extending beneath the near-shore riverbed remains a continuing contaminant source to groundwater and the Columbia River. The initial pump-and treat system proved to be ineffective as a long-term solution because of the geochemical characteristics of Sr-90. Following an evaluation of potentialmore » Sr-90 treatment technologies and their applicability under 100 NR-2 Operable Unit hydrogeologic conditions, the U.S. Department of Energy and the Washington State Department of Ecology agreed to evaluate apatite sequestration as the primary remedial technology, combined with a secondary polishing step utilizing phytoextraction if necessary. Aqueous injection was initiated in July 2005 to assess the efficacy of in-situ apatite along the 100 m of shoreline where Sr-90 concentrations are highest. The remedial technology is being developed by Pacific Northwest National Laboratory. CH2M Hill Plateau Remediation Company is implementing this technology in the field with support from PNNL.« less

Eolian deposits in the Neoproterozoic Big Bear Group, San Bernardino Mountains, California, USA

USGS Publications Warehouse

Stewart, John H.

2005-01-01

Strata interpreted to be eolian are recognized in the Neoproterozoic Big Bear Group in the San Bernardino Mountains of southern California, USA. The strata consist of medium- to large-scale (30 cm to > 6 m) cross-stratified quartzite considered to be eolian dune deposits and interstratified thinly laminated quartzite that are problematically interpreted as either eolian translatent climbing ripple laminae, or as tidal-flat deposits. High index ripples and adhesion structures considered to be eolian are associated with the thinly laminated and cross-stratified strata. The eolian strata are in a succession that is characterized by flaser bedding, aqueous ripple marks, mudcracks, and interstratified small-scale cross-strata that are suggestive of a tidal environment containing local fluvial deposits. The eolian strata may have formed in a near-shore environment inland of a tidal flat. The Neoproterozoic Big Bear Group is unusual in the western United States and may represent a remnant of strata that were originally more widespread and part of the hypothetical Neoproterozoic supercontinent of Rodinia. The Big Bear Group perhaps is preserved only in blocks that were downdropped along Neoproterozoic extensional faults. The eolian deposits of the Big Bear Group may have been deposited during arid conditions that preceded worldwide glacial events in the late Neoproterozoic. Possibly similar pre-glacial arid events are recognized in northern Mexico, northeast Washington, Australia, and northwest Canada.

Distribution of living larger benthic foraminifera in littoral environments of the United Arab Emirates

NASA Astrophysics Data System (ADS)

Fiorini, Flavia; Lokier, Stephen W.

2015-04-01

The distribution of larger benthic foraminifera in Recent littoral environment of the United Arab Emirates (Abu Dhabi and Western regions) was investigated with the aim of understanding the response of those foraminifera to an increase in water salinity. For this purpose, 100 sediment samples from nearshore shelf, beach-front, channel, lagoon, and intertidal environment were collected. Sampling was undertaken at a water depth shallower than 15 m in water with a temperature of 22 to 35˚C, a salinity ranging from 40 to 60‰ and a pH of 8. Samples were stained with rose Bengal at the moment of sample collection in order to identify living specimens. The most abundant epiphytic larger benthic foraminifera in the studied area were Peneroplis pertusus and P. planatus with less common Spirolina areatina, S. aciculate and Sorites marginalis. The living specimens of the above mentioned species with normal test growing were particularly abundant in the nearshore shelf and lagoonal samples collected on seaweed. Dead specimens were concentrated in the coarser sediments of the beach-front, probably transported from nearby environments. Shallow coastal ponds are located in the upper intertidal zone and have a maximum salinity of 60‰ and contain abundant detached seagrass. Samples collected from these ponds possess a living foraminifera assemblage dominated by Peneroplis pertusus and P. planatus. High percentages (up to 50% of the stained assemblage) of Peneroplis presented abnormality in test growth, such as the presence of multiple apertures with reduced size, deformation in the general shape of the test, irregular suture lines and abnormal coiling. The high percentage of abnormal tests reflects natural environmental stress mainly caused by high and variable salinity. The unique presence of living epiphytic species, suggests that epiphytic foraminifera may be transported into the pond together with seagrass and continued to live in the pond. This hypothesis is supported by the fact that all of the foraminifera with abnormal test growth were adults and exhibiting a normal proloculus and normal growth of the earlier chambers.

Late Pleistocene mammoth remains from Coastal Maine, USA

USGS Publications Warehouse

Hoyle, B.G.; Fisher, D.C.; Borns, H.W.; Churchill-Dickson, L. L.; Dorion, C.C.; Weddle, T.K.

2004-01-01

Remains identified as those of a woolly mammoth ( Mammuthus primigenius ) dated at 12,200 ?? 55 14C yr B.P. were recovered while excavating in a complex sequence of glaciomarine sediments in Scarborough, Maine, USA. The mammoth was found in the top meter of a fossiliferous unit of mud and sand laminites. These sediments were deposited during a marine regressive phase following the transgression that accompanied northward retreat of the margin of the Laurentide ice sheet. A Portlandia arctica valve from the underlying transgressive unit provides a minimum age of 14,820 ?? 105 14C yr B.P. for local deglaciation. The mammoth, an adult female, died in midwinter with no evidence of human involvement. Tusk growth rates and oxygen-isotope variation over the last few years of life record low seasonality. The mammoth was transported to the site as a partial carcass by the late-glacial proto-Saco River. It sank in a near-shore setting, was subjected to additional disarticulation and scattering of elements, and was finally buried in sediments reworked by the shallowing sea. ?? 2004 University of Washington. All rights reserved.

Micromorphologic evidence for paleosol development in the Endicott group, Siksikpuk formation, Kingak(?) shale, and Ipewik formation, western Brooks range, Alaska

USGS Publications Warehouse

Dumoulin, Julie A.; White, Tim

2005-01-01

Micromorphologic evidence indicates the presence of paleosols in drill-core samples from four sedimentary units in the Red Dog area, western Brooks Range. Well-developed sepic-plasmic fabrics and siderite spherules occur in claystones of the Upper Devonian through Lower Mississippian(?) Kanayut Conglomerate (Endicott Group), the Pennsylvanian through Permian Siksikpuk Formation (Etivluk Group), the Jurassic through Lower Cretaceous Kingak(?) Shale, and the Lower Cretaceous Ipewik Formation. Although exposure surfaces have been previously recognized in the Endicott Group and Kingak Shale on the basis of outcrop features, our study is the first microscopic analysis of paleosols from these units, and it provides the first evidence of subaerial exposure in the Siksikpuk and Ipewik Formations. Regional stratigraphic relations and geochemical data support our interpretations. Paleosols in the Siksikpuk, Kingak, and Ipewik Formations likely formed in nearshore coastal-plain environments, with pore waters subjected to inundation by the updip migration of slightly brackish ground water, whereas paleosols in the Kanayut Conglomerate probably formed in a more distal setting relative to a marine basin.

Patterns and processes of population change in selected nearshore vertebrate predators

USGS Publications Warehouse

Bodkin, James L.; Ballachey, Brenda E.; Dean, T.A.; Esler, Daniel N.

2003-01-01

Sea otters and harlequin ducks have not fully recovered from the oil spill. This project will explore links between oil exposure and the lack of population recovery, with the intent of understanding constraints to recovery of these species and the nearshore environment. In FY 02, sea otter work will include aerial surveys of distribution and abundance and estimates of age-specific survival rates. Harlequin duck field studies will examine the relationship between survival and CYP1A. Captive experiments on harlequin ducks will examine the relationships between oil exposure and CYP1A induction, and metabolic and behavioral consequences of exposure.

Numerical modeling of the effects of wave energy converter characteristics on nearshore wave conditions

DOE PAGES

Chang, G.; Ruehl, K.; Jones, C. A.; ...

2015-12-24

Modeled nearshore wave propagation was investigated downstream of simulated wave energy converters (WECs) to evaluate overall near- and far-field effects of WEC arrays. Model sensitivity to WEC characteristics and WEC array deployment scenarios was evaluated using a modified version of an industry standard wave model, Simulating WAves Nearshore (SWAN), which allows the incorporation of device-specific WEC characteristics to specify obstacle transmission. The sensitivity study illustrated that WEC device type and subsequently its size directly resulted in wave height variations in the lee of the WEC array. Wave heights decreased up to 30% between modeled scenarios with and without WECs formore » large arrays (100 devices) of relatively sizable devices (26 m in diameter) with peak power generation near to the modeled incident wave height. Other WEC types resulted in less than 15% differences in modeled wave height with and without WECs, with lesser influence for WECs less than 10 m in diameter. Wave directions and periods were largely insensitive to changes in parameters. Furthermore, additional model parameterization and analysis are required to fully explore the model sensitivity of peak wave period and mean wave direction to the varying of the parameters.« less

The genus Krithe (Ostracoda) from the Campanian and Maastrichtian (Upper Cretaceous) of the northern US Gulf Coastal Plain

USGS Publications Warehouse

Puckett, T.M.

1997-01-01

The ostracode genus Krithe is one of the most common genera in the Upper Cretaceous (late Santonian to Maastrichtian) deposits of the northern Gulf Coastal Plain of North America. Although it is never abundant, the genus occurs in sediments that were deposited under a wide range of palaeoenvironments, including nearshore sandy marls to offshore, nearly pure, chalk. The taxonomy of this taxon has been problematical, and what is herein considered to be a single species, K. cushmani, has been referred to in the literature under five different names. Two morphotypes were observed: relatively large individuals with 'mushroom'-shaped vestibules collected from chalk, and smaller individuals with pocket-shaped vestibules collected from nearshore deposits. Species of Krithe have been hypothesized to be useful in estimating dissolved oxygen concentration in ancient ocean floors, based on details of their morphology. Whereas the relationship between size and environment corroborates with previous predictions (larger individuals live in deeper water), the morphology of the vestibules contradicts predictions (the larger vestibules occur in the nearshore deposits and the smaller, more constricted vestibules occur in the chalk). A causal relationship between environment and morphology is discussed.

Eutrophication monitoring for Lake Superior's Chequamegon ...

EPA Pesticide Factsheets

A priority for the Lake Superior CSMI was to identify susceptible nearshore eutrophication areas. We developed an integrated sampling design to collect baseline data for Lake Superior’s Chequamegon Bay to understand how nearshore physical processes and tributary loading relate to observed chlorophyll concentrations. Sampling included ship-based water samples combined with vertical CTD casts, continuous in situ towing and data collected from an autonomous underwater glider. Sampling was conducted during June, July and September. The glider collected regional data as part of three extended missions in Lake Superior over the same periods. During the study, two significant storm events impacted the western end of Lake Superior; the first occurred during July 11-12, with 8-10 inches of rain in 24hrs, and the second on July 21 with winds in excess of 161 km/h. Using GIS software, we organized these diverse temporal data sets along a continuous time line with temporally coincident Modis Satellite data to visualize surface sediment plumes in relation to water quality measurements. Preliminary results suggest that both events impacted regional water quality, and that nearshore physical forces (upwelling and currents) influenced the spatial variability. Results comparing in situ measures with remotely sensed images will be discussed. not applicable

Coral Skeletons Provide Historical Evidence of Phosphorus Runoff on the Great Barrier Reef

PubMed Central

Mallela, Jennie; Lewis, Stephen E.; Croke, Barry

2013-01-01

Recently, the inshore reefs of the Great Barrier Reef have declined rapidly because of deteriorating water quality. Increased catchment runoff is one potential culprit. The impacts of land-use on coral growth and reef health however are largely circumstantial due to limited long-term data on water quality and reef health. Here we use a 60 year coral core record to show that phosphorus contained in the skeletons (P/Ca) of long-lived, near-shore Porites corals on the Great Barrier Reef correlates with annual records of fertiliser application and particulate phosphorus loads in the adjacent catchment. Skeletal P/Ca also correlates with Ba/Ca, a proxy for fluvial sediment loading, again linking near-shore phosphorus records with river runoff. Coral core records suggest that phosphorus levels increased 8 fold between 1949 and 2008 with the greatest levels coinciding with periods of high fertiliser-phosphorus use. Periods of high P/Ca correspond with intense agricultural activity and increased fertiliser application in the river catchment following agricultural expansion and replanting after cyclone damage. Our results demonstrate how coral P/Ca records can be used to assess terrestrial nutrient loading of vulnerable near-shore reefs. PMID:24086606

Nearshore Dynamics Around Outer Sebastián Vizcaíno Bay

NASA Astrophysics Data System (ADS)

Alnajjar, M.; Woodson, C. B.; Monismith, S. G.; Boch, C. A.; Micheli, F.; Vazquez, W. L.

2016-02-01

We present results from our long-term observational study (Mar 2013 - Sept 2015) along the Pacific coast of Baja California peninsula. The presented field data examines the physical hydrodynamics of nearshore processes at Isla San Jeronímo, Isla Natividad, and Isla Magdalena in Baja California, MX. One objective of the study was to understand the potential effects of climate change on that region. The data shows high variation in current magnitude and water temperature that appear related to the presence, or lack thereof, of kelp in the region. Isla Natividad and Isla San Jeronímo, are both upwelling regions within the California Current System, while Isla Magdalena is subtropical. Isla Natividad exhibits large spatial and temporal variability, partially attributed to its unique location in a transitional region between temperate and subtropical waters. The variability of nearshore signal frequency on different sides of Isla Natividad is as large as the difference between Isla San Jeronímo and Isla Magdalena, 420 miles away. Different exposure regimes observed at Isla Natividad led to the coherence between Isla San Jeronímo and Isla Natividad, being larger than that found on either side of Isla Natividad.

Adjoint-Based Sensitivity Maps for the Nearshore

NASA Astrophysics Data System (ADS)

Orzech, Mark; Veeramony, Jay; Ngodock, Hans

2013-04-01

The wave model SWAN (Booij et al., 1999) solves the spectral action balance equation to produce nearshore wave forecasts and climatologies. It is widely used by the coastal modeling community and is part of a variety of coupled ocean-wave-atmosphere model systems. A variational data assimilation system (Orzech et al., 2013) has recently been developed for SWAN and is presently being transitioned to operational use by the U.S. Naval Oceanographic Office. This system is built around a numerical adjoint to the fully nonlinear, nonstationary SWAN code. When provided with measured or artificial "observed" spectral wave data at a location of interest on a given nearshore bathymetry, the adjoint can compute the degree to which spectral energy levels at other locations are correlated with - or "sensitive" to - variations in the observed spectrum. Adjoint output may be used to construct a sensitivity map for the entire domain, tracking correlations of spectral energy throughout the grid. When access is denied to the actual locations of interest, sensitivity maps can be used to determine optimal alternate locations for data collection by identifying regions of greatest sensitivity in the mapped domain. The present study investigates the properties of adjoint-generated sensitivity maps for nearshore wave spectra. The adjoint and forward SWAN models are first used in an idealized test case at Duck, NC, USA, to demonstrate the system's effectiveness at optimizing forecasts of shallow water wave spectra for an inaccessible surf-zone location. Then a series of simulations is conducted for a variety of different initializing conditions, to examine the effects of seasonal changes in wave climate, errors in bathymetry, and variations in size and shape of the inaccessible region of interest. Model skill is quantified using two methods: (1) a more traditional correlation of observed and modeled spectral statistics such as significant wave height, and (2) a recently developed RMS spectral skill score summed over all frequency-directional bins. The relative advantages and disadvantages of these two methods are considered. References: Booij, N., R.C. Ris, and L.H. Holthuijsen, 1999: A third-generation wave model for coastal regions: 1. Model description and validation. J. Geophys. Res. 104 (C4), 7649-7666. Orzech, M.D., J. Veeramony, and H.E. Ngodock, 2013: A variational assimilation system for nearshore wave modeling. J. Atm. & Oc. Tech., in press.

Projected changes of the southwest Australian wave climate under two atmospheric greenhouse gas concentration pathways

NASA Astrophysics Data System (ADS)

Wandres, Moritz; Pattiaratchi, Charitha; Hemer, Mark A.

2017-09-01

Incident wave energy flux is responsible for sediment transport and coastal erosion in wave-dominated regions such as the southwestern Australian (SWA) coastal zone. To evaluate future wave climates under increased greenhouse gas concentration scenarios, past studies have forced global wave simulations with wind data sourced from global climate model (GCM) simulations. However, due to the generally coarse spatial resolution of global climate and wave simulations, the effects of changing offshore wave conditions and sea level rise on the nearshore wave climate are still relatively unknown. To address this gap of knowledge, we investigated the projected SWA offshore, shelf, and nearshore wave climate under two potential future greenhouse gas concentration trajectories (representative concentration pathways RCP4.5 and RCP8.5). This was achieved by downscaling an ensemble of global wave simulations, forced with winds from GCMs participating in the Coupled Model Inter-comparison Project (CMIP5), into two regional domains, using the Simulating WAves Nearshore (SWAN) wave model. The wave climate is modeled for a historical 20-year time slice (1986-2005) and a projected future 20-year time-slice (2081-2100) for both scenarios. Furthermore, we compare these scenarios to the effects of considering sea-level rise (SLR) alone (stationary wave climate), and to the effects of combined SLR and projected wind-wave change. Results indicated that the SWA shelf and nearshore wave climate is more sensitive to changes in offshore mean wave direction than offshore wave heights. Nearshore, wave energy flux was projected to increase by ∼10% in exposed areas and decrease by ∼10% in sheltered areas under both climate scenarios due to a change in wave directions, compared to an overall increase of 2-4% in offshore wave heights. With SLR, the annual mean wave energy flux was projected to increase by up to 20% in shallow water (< 30 m) as a result of decreased wave dissipation. In winter months, the longshore wave energy flux, which is responsible for littoral drift, is expected to increase by up to 39% (62%) under the RCP4.5 (RCP8.5) greenhouse gas concentration pathway with SLR. The study highlights the importance of using high-resolution wave simulations to evaluate future regional wave climates, since the coastal wave climate is more responsive to changes in wave direction and sea level than offshore wave heights.

Franz Josef Land: extreme northern outpost for Arctic fishes

PubMed Central

Chernova, Natalia V.; Turchik, Alan; Sala, Enric

2014-01-01

The remote Franz Josef Land (FJL) Archipelago is the most northerly land in Eurasia and its fish fauna, particularly in nearshore habitats, has been poorly studied. An interdisciplinary expedition to FJL in summer 2013 used scuba, seines, and plankton nets to comprehensively study the nearshore fish fauna of the archipelago. We present some of the first underwater images for many of these species in their natural habitats. In addition, deep water drop cameras were deployed between 32 and 392 m to document the fish fauna and their associated habitats at deeper depths. Due to its high latitude (79°–82°N), extensive ice cover, and low water temperatures (<0 °C much of the year), the fish diversity at FJL is low compared to other areas of the Barents Sea. Sixteen species of fishes from seven families were documented on the expedition, including two species previously unknown to the region. One Greenland shark, Somniosus microcephalus (Somniosidae), ca. 2 m in length, was recorded by drop camera near Hayes Island at 211 m, and Esipov’s pout, Gymnelus esipovi (Zoarcidae), was collected at Wilton Island at 15 m in a kelp forest. Including the tape-body pout, Gymnelus taeniatus, described earlier from the sub-littoral zone of Kuhn Island, 17 fish species are now known from FJL’s nearshore waters. Species endemic to the Arctic accounted for 75% of the nearshore species observed, followed by species with wider ranges. A total of 43 species from 15 families are known from FJL with the majority of the records from offshore trawl surveys between 110 and 620 m. Resident species have mainly high Arctic distributions, while transient species visit the archipelago to feed (e.g., Greenland shark), and others are brought by currents as larvae and later migrate to spawn grounds in the south (e.g., Atlantic cod Gadus morhua, Capelin Mallotus villosus, Beaked redfish Sebastes mentella). Another species group includes warmer-water fishes that are rare waifs (e.g., Glacier lanternfish Benthosema glaciale, White barracudina Arctozenus rissoi). The rapid warming of the Arctic will likely result in significant changes to the entire ecosystem and this study therefore serves as an important baseline for the nearshore fish assemblages in this unique and fragile region. PMID:25538869

Nearshore Circulation and Storm Surge Along the Mackenzie Delta Coast

NASA Astrophysics Data System (ADS)

Perrie, W.; Mulligan, R. P.; Solomon, S. M.; Hoque, A.; Zhang, L.

2008-12-01

The Mackenzie Delta is a 150 km long section of coastline characterized by muddy sediments where the Mackenzie River outflow, dispersed over 20 distributary channels, discharges into the southern Beaufort Sea. The marine environment in this region is an important and integral part of the lives of Canadian Northerners. The area is also undergoing hydrocarbon exploration with potential development within the next decade. Changes to Arctic climate, such as increasing ice-free western Arctic Ocean and intensifying storm activity, may endanger the coastal settlements and marine environment in the Mackenzie Delta region. The low gradient of the delta and the adjacent inner shelf makes it very susceptible to flooding during storms. Field observations in the nearshore zone collected in August of 2007 and 2008 indicate strong gradients in temperature and salinity in shallow water of 2-6 m. The fluctuations are associated with the movements of warm and fresh river plumes and wind-driven upwelling of cold and saline water below the thermocline. The observations are in agreement with 3D model simulations of the nearshore delta region using Delft3D, which includes wind, tidal, storm surge, buoyancy and river forcing. The results validate the model and indicate that it can be used to hindcast the nearshore oceanographic conditions during severe Arctic storms. As a case study we present preliminary model results for an Arctic storm from late 1999 that caused extensive vegetation die-off in the outer delta. This cyclone was a mesoscale Arctic storm that developed over the NE Pacific and western Bering Sea, intensified explosively in the Gulf of Alaska and developed into a meteorological bomb. The storm made landfall at Cape Newenham, Alaska, crossed the Rocky Mountains to the Yukon and Northwest Territories and re-intensified over a zone of high sea surface temperature gradients in the southern Beaufort Sea. Using the Canadian Mesoscale Compressible Community (MC2) atmospheric model, simulations of the storm pattern, track and intensity are in very good agreement with the NCEP re-analysis. This is model coupled to the Princeton Ocean Model (POM) and Hibler Ice Model, which are used to provide basin-scale driver fields and define the boundary conditions of the nearshore Delft3D model for the Mackenzie Delta region. Coastal damage was predominately caused by storm surge, and the high salinity flood waters that flowed over the surface of the outer delta.

Franz Josef Land: extreme northern outpost for Arctic fishes.

PubMed

Chernova, Natalia V; Friedlander, Alan M; Turchik, Alan; Sala, Enric

2014-01-01

The remote Franz Josef Land (FJL) Archipelago is the most northerly land in Eurasia and its fish fauna, particularly in nearshore habitats, has been poorly studied. An interdisciplinary expedition to FJL in summer 2013 used scuba, seines, and plankton nets to comprehensively study the nearshore fish fauna of the archipelago. We present some of the first underwater images for many of these species in their natural habitats. In addition, deep water drop cameras were deployed between 32 and 392 m to document the fish fauna and their associated habitats at deeper depths. Due to its high latitude (79°-82°N), extensive ice cover, and low water temperatures (<0 °C much of the year), the fish diversity at FJL is low compared to other areas of the Barents Sea. Sixteen species of fishes from seven families were documented on the expedition, including two species previously unknown to the region. One Greenland shark, Somniosus microcephalus (Somniosidae), ca. 2 m in length, was recorded by drop camera near Hayes Island at 211 m, and Esipov's pout, Gymnelus esipovi (Zoarcidae), was collected at Wilton Island at 15 m in a kelp forest. Including the tape-body pout, Gymnelus taeniatus, described earlier from the sub-littoral zone of Kuhn Island, 17 fish species are now known from FJL's nearshore waters. Species endemic to the Arctic accounted for 75% of the nearshore species observed, followed by species with wider ranges. A total of 43 species from 15 families are known from FJL with the majority of the records from offshore trawl surveys between 110 and 620 m. Resident species have mainly high Arctic distributions, while transient species visit the archipelago to feed (e.g., Greenland shark), and others are brought by currents as larvae and later migrate to spawn grounds in the south (e.g., Atlantic cod Gadus morhua, Capelin Mallotus villosus, Beaked redfish Sebastes mentella). Another species group includes warmer-water fishes that are rare waifs (e.g., Glacier lanternfish Benthosema glaciale, White barracudina Arctozenus rissoi). The rapid warming of the Arctic will likely result in significant changes to the entire ecosystem and this study therefore serves as an important baseline for the nearshore fish assemblages in this unique and fragile region.

Nearshore drift dynamics of natural versus artificial seagrass wrack

NASA Astrophysics Data System (ADS)

Baring, Ryan J.; Fairweather, Peter G.; Lester, Rebecca E.

2018-03-01

Drifting macrophytes such as seagrass and macroalgae are commonly found washed ashore on sandy beaches but few studies have investigated the drift trajectories of macrophytes whilst near to the coast. This is the first study to investigate the surface drifting of small clumps of seagrass released at various distances from shore, across multiple days with contrasting wind and tidal conditions, in a large gulf in southern Australia. Natural and artificial radio-tagged seagrass units generally travelled in the same directions as tides but trajectories were variable across sampling days and when tagged units were released at different distances from shore. Natural and artificial units diverged from each other particularly on days when wind speeds increased but generally drifted in the same direction and ended up within close proximity to each other at the 6-h endpoint. During calm conditions, tagged seagrass units drifted with tides for 0.25-5 km and, during one sampling day when wind speeds increased, drifted for >5 km over the 6-h time period. Only tagged units that were released closest to shore stranded on sandy beaches within the six hours of observation, so it would be difficult to predict the eventual stranding location on shorelines for macrophytes released further offshore. This study provides evidence of the variability of macrophyte drift dynamics near to coastlines. Acknowledging this variability is essential for further understanding of the ecological significance of allochthonous material arriving at shorelines, which should be integrated into future research and management of sandy-beach ecosystems.

Coastal monitoring of the May 2005 dredge disposal offshore of Ocean Beach, San Francisco, Calif.

USGS Publications Warehouse

Barnard, Patrick L.; Hanes, Daniel M.

2006-01-01

Ocean Beach, California, contains an erosion hot spot in the shadow of the San Francisco ebb tidal delta south of Sloat Boulevard that threatens valuable public infrastructure as well as the safe recreational use of the beach. In an effort to reduce the erosion at this location and avoid hazardous navigation conditions at the current disposal site (SF-8), a new plan for the management of sediment dredged annually from the main shipping channel at the mouth of Francisco Bay was implemented in May 2005 by the United States Army Corps of Engineers, San Francisco District (COE). The objective for COE was to perform a test dredge disposal of ~230,000 m3 (300,000 yd3) of sand just offshore of the erosion hot spot, in depths between approximately 9 and 14 m. This disposal site was chosen because it is in a location where the strong tidal currents associated with the mouth of San Francisco Bay and waves can potentially feed sediment toward the littoral zone in the reach of the beach that is experiencing critical erosion. The onshore migration of sediment from the target disposal location might feed the primary longshore bar or the nearshore zone, and provide a buffer to erosion that peaks during winter months when large waves impact the region. The U.S. Geological Survey (USGS), in collaboration with the Sea Floor Mapping Lab (SFML) of California State University, Monterey Bay, monitored the initial bathymetric evolution of the test dredge disposal site and the adjacent coastal region from May 2005 to November 2005. This paper reports on this monitoring effort and assesses the short-term coastal response.

Understanding the scale of Marine protection in Hawai'i: from community-based management to the remote Northwestern Hawaiian Islands.

PubMed

Friedlander, Alan M; Stamoulis, Kostantinos A; Kittinger, John N; Drazen, Jeffrey C; Tissot, Brian N

2014-01-01

Ancient Hawaiians developed a sophisticated natural resource management system that included various forms of spatial management. Today there exists in Hawai'i a variety of spatial marine management strategies along a range of scales, with varying degrees of effectiveness. State-managed no-take areas make up less than 0.4% of nearshore waters, resulting in limited ecological and social benefits. There is increasing interest among communities and coastal stakeholders in integrating aspects of customary Hawaiian knowledge into contemporary co-management. A network of no-take reserves for aquarium fish on Hawai'i Island is a stakeholder-driven, adaptive management strategy that has been successful in achieving ecological objectives and economic benefits. A network of large-scale no-take areas for deepwater (100-400m) bottomfishes suffered from a lack of adequate data during their initiation; however, better technology, more ecological data, and stakeholder input have resulted in improvements and the ecological benefits are becoming clear. Finally, the Papahānaumokuākea Marine National Monument (PMNM) is currently the single largest conservation area in the United States, and one of the largest in the world. It is considered an unqualified success and is managed under a new model of collaborative governance. These case studies allow an examination of the effects of scale on spatial marine management in Hawai'i and beyond that illustrate the advantages and shortcomings of different management strategies. Ultimately a marine spatial planning framework should be applied that incorporates existing marine managed areas to create a holistic, regional, multi-use zoning plan engaging stakeholders at all levels in order to maximize resilience of ecosystems and communities.

Coastal retreat and shoreface profile variations in the Canadian Beaufort Sea

USGS Publications Warehouse

Hequette, A.; Barnes, P.W.

1990-01-01

The coastline of the southern Canadian Beaufort Sea consists primarily of unconsolidated bluffs. Although the sea is ice-free for 3 months of the year and wave energy is restricted by pack ice, the coast is undergoing regional retreat with erosion rates as high as 10 m a-1 in some locations. Simple and multiple regression analyses were carried out to determine the degree of correlation between the mean retreat rate measured at various locations and the different parameters that may control shoreline recession. Sediment texture, ground-ice content, cliff height, wave energy and shoreface gradient revealed medium to poor correlation with erosion rates, showing that the recessive evolution of the coastline can not be explained solely by wave-induced and subaerial processes. The comparison of nearshore echo-sounding records from 1987 with bathymetry from 1971 showed substantial erosion (up to 1 m) of the submarine profile between 12 and 15 m of water. There is strong evidence that this erosion has been caused by sea ice gouging on the seafloor. From depths of 5 to 9 m, accretion has taken place, possibly induced by ice-push processes, and inshore of the 5 m isobath wave and current erosion of the shoreface has occurred. These results suggest that the erosion of the inner shelf by ice gouging drives the erosion observed inshore on the coastal bluffs and nearshore zone as the shoreface profile strives for a state of dynamic equilibrium. ?? 1990.

Morphological evolution of the southwestern Black Sea coast of Turkey since the early 2000s: medium- vs. short-term changes

NASA Astrophysics Data System (ADS)

LiBassi, Nick; Özener, Haluk; Otay, Emre; Doğru, Aslı

2018-06-01

Coastal zones are in a state of continual flux worldwide, due in part to seasonal factors and in part to influences operating over longer periods of time. Discerning changes on different timescales remains a challenge. This study compares shoreline position and nearshore bathymetry over a time interval of 16 years in order to determine the extent of medium-term changes in comparison with short-term changes along the southwestern Black Sea coast of Turkey near Kilyos. For this purpose the results of surveys completed in 2001 and 2002 are compared with data collected in December 2015, September 2016, and March 2017 at the same location using a differential global positioning system (DGPS) in real-time kinematic (RTK) configuration combined with echo-sounder profiling. Average shoreline recession over the 16-year period (medium term) has been estimated at 3-4 cm/year as opposed to an average of 9.5 m in the 12-month period from June 2001 to June 2002 (short term). The medium-term nearshore sediment loss has been approx. 100-125 m3/m shoreline since the early 2000s. Over the same period a prominent offshore bar has moved seaward at a maximum rate of 1 m/year since 2002. Considering the large discrepancy in the shoreline recession rates recorded in the short and medium term, this aspect must be taken into account in any integrated coastal zone management strategy.

Trophic Ecology and Movement Patters of Tiger Sharks (Galeocerdo Cuvier) off the Western North Atlantic Coastal and Continental Shelf Waters

NASA Astrophysics Data System (ADS)

Sancho, G.; Edman, R.; Frazier, B.; Bubley, W.

2016-02-01

Understanding the trophic dynamics and habitat utilization of apex predators is central to inferring their influence on different marine landscapes and to help design effective management plans for these animals. Tiger sharks (Galeocerdo cuvier) are abundant in shelf and offshore Gulf Stream waters of the western North Atlantic Ocean, and based on movements from individuals captured in Florida and Bahamas, seem to avoid coastal and shelf waters off South Carolina and Georgia. This contradicts reports of tiger sharks regularly being caught nearshore by anglers in these states, indicating that separate sub-populations may exist in the western North Atlantic. In the present study we captured Tiger Sharks in coastal waters off South Carolina in 2014 and 2015 in order to describe their movement patterns through acoustic and satellite tagging, and trophic dynamics through stable isotope analyses. Movement data show that these tiger sharks repeatedly visit particular inshore areas and mainly travel over the continental shelf, but rarely venture offshore beyond the continental shelf edge. Ongoing C and N stable isotope analyses of muscle, blood and skin tissues from adult and juvenile tiger sharks, as well as from potential prey species and primary producers, will help determine if their diets are based on inshore, shelf or offshore based food webs. Tiger sharks exploiting nearshore environments and shelf waters have much higher probabilities of interacting with humans than individuals occupying far offshore Gulf Stream habitats.

Morphological evolution of the southwestern Black Sea coast of Turkey since the early 2000s: medium- vs. short-term changes

NASA Astrophysics Data System (ADS)

LiBassi, Nick; Özener, Haluk; Otay, Emre; Doğru, Aslı

2017-12-01

Coastal zones are in a state of continual flux worldwide, due in part to seasonal factors and in part to influences operating over longer periods of time. Discerning changes on different timescales remains a challenge. This study compares shoreline position and nearshore bathymetry over a time interval of 16 years in order to determine the extent of medium-term changes in comparison with short-term changes along the southwestern Black Sea coast of Turkey near Kilyos. For this purpose the results of surveys completed in 2001 and 2002 are compared with data collected in December 2015, September 2016, and March 2017 at the same location using a differential global positioning system (DGPS) in real-time kinematic (RTK) configuration combined with echo-sounder profiling. Average shoreline recession over the 16-year period (medium term) has been estimated at 3-4 cm/year as opposed to an average of 9.5 m in the 12-month period from June 2001 to June 2002 (short term). The medium-term nearshore sediment loss has been approx. 100-125 m3/m shoreline since the early 2000s. Over the same period a prominent offshore bar has moved seaward at a maximum rate of 1 m/year since 2002. Considering the large discrepancy in the shoreline recession rates recorded in the short and medium term, this aspect must be taken into account in any integrated coastal zone management strategy.

The emerging role of lidar remote sensing in coastal research and resource management

USGS Publications Warehouse

Brock, J.C.; Purkis, S.J.

2009-01-01

Knowledge of coastal elevation is an essential requirement for resource management and scientific research. Recognizing the vast potential of lidar remote sensing in coastal studies, this Special Issue includes a collection of articles intended to represent the state-of-the-art for lidar investigations of nearshore submerged and emergent ecosystems, coastal morphodynamics, and hazards due to sea-level rise and severe storms. Some current applications for lidar remote sensing described in this Special Issue include bluegreen wavelength lidar used for submarine coastal benthic environments such as coral reef ecosystems, airborne lidar used for shoreline mapping and coastal change detection, and temporal waveform-resolving lidar used for vegetation mapping. ?? 2009 Coastal Education and Research Foundation.

The emerging role of lidar remote sensing in coastal research and resource management

USGS Publications Warehouse

Brock, John C.; Purkis, Samuel J.

2009-01-01

Knowledge of coastal elevation is an essential requirement for resource management and scientific research. Recognizing the vast potential of lidar remote sensing in coastal studies, this Special Issue includes a collection of articles intended to represent the state-of-the-art for lidar investigations of nearshore submerged and emergent ecosystems, coastal morphodynamics, and hazards due to sea-level rise and severe storms. Some current applications for lidar remote sensing described in this Special Issue include bluegreen wavelength lidar used for submarine coastal benthic environments such as coral reef ecosystems, airborne lidar used for shoreline mapping and coastal change detection, and temporal waveform-resolving lidar used for vegetation mapping.

Bathymetry and Acoustic Backscatter: Northern Santa Barbara Channel, Southern California

USGS Publications Warehouse

Dartnell, Pete; Finlayson, David; Conrad, Jamie; Cochrane, Guy; Johnson, Samuel

2010-01-01

In the summer of 2008, as part of the California Seafloor Mapping Program (CSMP) the U.S. Geological Survey, Coastal and Marine Geology mapped a nearshore region of the northern Santa Barbara Channel in Southern California (fig 1). The CSMP is a cooperative partnership between Federal and State agencies, Universities, and Industry to create a comprehensive coastal/marine geologic and habitat basemap series to support the Marine Life Protection Act (MLPA) inititive. The program is supported by the California Ocean Protection Council and the California Coastal Conservancy. The 2008 mapping collected high resolution bathymetry and acoustic backscatter data using a bathymetric side scan system within State waters from about the 10-m isobath out over 3-nautical miles. This Open-File Report provides these data in a number of different formats, as well as a summary of the mapping mission, maps of bathymetry and backscatter, and FGDC metadata.

Mechanisms controlling the complete accretionary beach state sequence

NASA Astrophysics Data System (ADS)

Dubarbier, Benjamin; Castelle, Bruno; Ruessink, Gerben; Marieu, Vincent

2017-06-01

Accretionary downstate beach sequence is a key element of observed nearshore morphological variability along sandy coasts. We present and analyze the first numerical simulation of such a sequence using a process-based morphodynamic model that solves the coupling between waves, depth-integrated currents, and sediment transport. The simulation evolves from an alongshore uniform barred beach (storm profile) to an almost featureless shore-welded terrace (summer profile) through the highly alongshore variable detached crescentic bar and transverse bar/rip system states. A global analysis of the full sequence allows determining the varying contributions of the different hydro-sedimentary processes. Sediment transport driven by orbital velocity skewness is critical to the overall onshore sandbar migration, while gravitational downslope sediment transport acts as a damping term inhibiting further channel growth enforced by rip flow circulation. Accurate morphological diffusivity and inclusion of orbital velocity skewness opens new perspectives in terms of morphodynamic modeling of real beaches.

Evaluation of beach grooming techniques on Escherichia coli density in foreshore sand at North Beach, Racine, WI

USGS Publications Warehouse

Kinzelman, Julie L.; Whitman, Richard L.; Byappanahalli, Muruleedhara N.; Jackson, Emma; Bagley, Robert C.

2003-01-01

Elevated levels of Escherichia coli(E. coli) in bathing waters at North Beach, a popular recreational site in Racine, Wisconsin, have been a persistent problem often resulting in the issuance of poor water quality advisories. Moreover, waterfowl (mostly Larus delawarensis and L. argentatus) in nearshore and offshore areas are common and may serve as non-point sources for bacterial contamination of recreational waters. Current beach management practice involves daily mechanical grooming of the nearshore sand for aesthetics and removal of hazardous debris. However, this practice has not been evaluated in terms of its effects on E. coli loading to beach sand and potential introduction to contiguous swimming water. In this study, we tested E. coli responses to three treatments: mechanical groomer, daily and twice weekly hand raking, and a control (no raking/grooming). A randomized block design consisted of replicated treatments and one control (10 each), for a total of 40 blocks sampled daily for 10 days. Foreshore sand samples were collected by hand coring to an average depth of 10 cm. Median E. colirecovered were 73 (mechanically groomed), 27 (hand-raked daily), 32 (hand-raked twice weekly), and 22 (control) colony-forming units (CFU) per gram dry weight sand. E. colicounts in sand that was groomed were significantly higher than hand rakings and control (p <0.0001), and there was no significant difference between control and raking treatments (p<0.01). This study demonstrates the beach management implications related to grooming efficacy and the importance of understanding non-point sources of bacterial contamination.

Maps showing estimated sediment yield from coastal landslides and active slope distribution along the Big Sur coast, Monterey and San Luis Obispo Counties, California

USGS Publications Warehouse

Hapke, Cheryl J.; Green, Krystal R.; Dallas, Kate

2004-01-01

The 1982-83 and 1997-98 El Ni?os brought very high precipitation to California?s central coast; this precipitation resulted in raised groundwater levels, coastal flooding, and destabilized slopes throughout the region. Large landslides in the coastal mountains of Big Sur in Monterey and San Luis Obispo Counties blocked sections of California State Route 1, closing the road for months at a time. Large landslides such as these occur frequently in the winter months along the Big Sur coast due to the steep topography and weak bedrock. A large landslide in 1983 resulted in the closure of Highway 1 for over a year to repair the road and stabilize the slope. Resulting work from the 1983 landslide cost over $7 million and generated 30 million cubic yards of debris from landslide removal and excavations to re-establish the highway along the Big Sur coast. Before establishment of the Monterey Bay National Marine Sanctuary (MBNMS) in 1992, typical road opening measures involved disposal of some landslide material and excess material generated from slope stabilization onto the seaward side of the highway. It is likely that some or most of this disposed material, either directly or indirectly through subsequent erosion, was eventually transported downslope into the ocean. In addition to the landslides that initiate above the road, natural slope failures sometimes occur on the steep slopes below the road and thus deliver material to the base of the coastal mountains where it is eroded and dispersed by waves and nearshore currents. Any coastal-slope landslide, generated through natural or anthropogenic processes, can result in sediment entering the nearshore zone. The waters offshore of the Big Sur coast are part of the MBNMS. Since it was established in 1992, landslide-disposal practices came under question for two reasons. The U.S. Code of Federal Regulations, Title 15, Section 922.132 prohibits discharging or depositing, from beyond the boundary of the Sanctuary, any material or other matter that subsequently enters the Sanctuary and injures a Sanctuary resource or quality. The landslide-disposal practices previously used had the potential to alter nearshore zone habitat by converting marine habitats from rocky substrate to soft bottom. In addition, the disposal practices had the potential to increase concentrations of suspended sediment in the nearshore zone, and thereby possibly impact coastal biological communities. On the other hand, natural mass-wasting processes, including coastal cliff erosion coastal and landslides, as well as streams deliver sediment to the coast in unknown quantities and thus provide nutrients as well as source material for beaches. Current road maintenance and repair practices along the Coast Highway 1 corridor that restrict disposal of material within the MBNMS may actually reduce sediment input relative to natural processes.

Marine geology and bathymetry of nearshore shelf of Chukchi Sea, Ogotoruk Creek area, northwest Alaska

USGS Publications Warehouse

Scholl, D. W.; Sainsbury, C.L.

1960-01-01

During July and August 1958 the U.S. Geological Survey conducted a study in behalf of the Atomic Energy Commission of the oceanography, bathymetry, and marine geology of the nearshore shelf of the Chukchi Sea off the Ogotoruk Creek area, northwest Alaska. Ogotoruk Creek enters the Chukchi Sea about 32 miles southeast of the large cuapate spit of Point Hope at long 165 degrees 4446 W. and lat 68 degrees 0551 N. The Ogotoruk Creek area extends approximately 10 miles west and 7 miles east of the creek mouth. Knowledge of the marine geology and oceanography is confined primarily to the nearshore shelf, which includes about 70 square miles of the shelf and is defined as the sea floor lying shoreward of the 50-foot submarine contour. The 50-foot contour generally lies from 2 to 4 miles from shore. Submarine topography was studied to a distance of 15 miles from shore over an area of approximately 340 square miles. A northwest coastal current flows past the Ogotoruk Creek area and during July and August averaged 0.5 mile per hour. Persistent northerly winds cause general upwelling near shore and at times of pronounced upwelling the coastal current was reversed or appreciably reduced in speed. Longshore currents shoreward of the breaker zone averaged 0.3 mile per hour and moved to the east for the greater part of the time of the study. The overall seaward slope of the inner 15 miles of the Chukchi shelf from a depth of 40 to 135 feet is approximately 0 degrees 04, or about 6 feet per mile. Slopes near shore to depths of 15-20 feet are steep and average 2 degrees 30. Beyond these depths they increase gradually out to a depth of 40-45 feet. Seaward of this point the shelf is flattest and slopes are as low as 0 degree 01. This terrace or flat part of the nearshore shelf is about 2 miles wide and descends to a depth of 50-55 feet beyond which the gradient increases to about 0 degree 06. At depths greater than 85 feet the submarine declivity gradually decreases to 0 degree 03 at a distance of 15 miles from shore. A flat-bottomed trough, Ogotoruk Seavalley, heads about a quarter of a mile from shore off the mouth of Ogotoruk Creek. The shallow seavalley averages only 6 feet in relief and extends 15 miles from shore to a depth of 135 feet. A number of smaller channels also indent the gentle sloping inner Chukchi shelf east of the seavalley and nearshore west of it. Many outcrops of Paleozoic and Mesozoic formations on the nearshore shelf indicate that it is a wave-planed platform. Wave planation is thought to have taken place primarily in Sangamon and rpre-Sangamon time (approximately 100,000 to 1,000,000 years ago). Ogotoruk Seavalley is believed to be a drowned subaerial valley which was excavated by Ogotoruk Creek during periods of glacially depressed sea level. Unconsolidated sediments overlying the nearshore shelf are chiefly slightly rounded residual gravel which have been derived from submerged outcrops. Detrital sand and silt, contributed from the nearby coastal area during Recent time, overlie the shelf near shore and at depth as much as 50 feet seaward of segments of the coast underlain by fine-grained clastic rocks of Mesozoic age. Owing to a small volume of detrital clasts contributed by the coastal area detrital sedimentation is not prominent over the nearshore shelf. Beaches fronting the Ogotoruk Creek area are 30-260 feet wide, range from less than 10 to about 25 feet thick, and are composed of sandy gravel having a median diameter of about 10 mm. Rounded clasts of greywacke, siltstone, limestone, and chert are the principal constituents of the gravel. Longshore currents accompanying moderate storms transport gravel and sand parallel to shore at rates of 5 cubic yards per hour. Sediment transported by longshore currents accumulates as spits at stream mouths and as areas of new beach below rocky headlands.

Minor-element composition and organic carbon content of marine and nonmarine shales of Late Cretaceous age in the western interior of the United States

USGS Publications Warehouse

Tourtelot, H.A.

1964-01-01

The composition of nonmarine shales of Cretaceous age that contain less than 1 per cent organic carbon is assumed to represent the inherited minor-element composition of clayey sediments delivered to the Cretaceous sea that occupied the western interior region of North America. Differences in minor-element content between these samples and samples of 1. (a) nonmarine carbonaceous shales (1 to 17 per cent organic carbon), 2. (b) nearshore marine shales (less than 1 per cent organic carbon), and 3. (c) offshore marine shales (as much as 8 per cent organic carbon), all of the same age, reveal certain aspects of the role played by clay minerals and organic materials in affecting the minor-element composition of the rocks. The organic carbon in the nonmarine rocks occurs in disseminated coaly plant remains. The organic carbon in the marine rocks occurs predominantly in humic material derived from terrestrial plants. The close similarity in composition between the organic isolates from the marine samples and low-rank coal suggests that the amount of marine organic material in these rocks is small. The minor-element content of the two kinds of nonmarine shales is the same despite the relatively large amount of organic carbon in the carbonaceous shales. The nearshore marine shales, however, contain larger median amounts of arsenic, boron, chromium, vanadium and zinc than do the nonmarine rocks; and the offshore marine shales contain even larger amounts of these elements. Cobalt, molybdenum, lead and zirconium show insignificant differences in median content between the nonmarine and marine rocks, although as much as 25 ppm molybdenum is present in some offshore marine samples. The gallium content is lower in the marine than in the nonmarine samples. Copper and selenium contents of the two kinds of nonmarine rocks and the nearshore marine samples are the same, but those of the offshore samples are larger. In general, arsenic, chromium, copper, molybdenum, selenium, vanadium and zinc are concentrated in those offshore marine samples having the largest amounts of organic carbon, but samples with equal amounts of vanadium, for instance, may differ by a factor of 3 in their amount of organic carbon. Arsenic and molybdenum occur in some samples chiefly in syngenetic pyrite but also are present in relatively large amounts in samples that contain little pyrite. The data on nonmarine carbonaceous shales indicate that organic matter of terrestrial origin in marine shales contributes little to the minor-element content of such rocks. It is possible that marine organic matter, even though seemingly small in amount in marine shales, contributes to the minor-element composition of the shales. In addition to any such contribution, however, the great effectiveness in sorption processes of humic materials in conjunction with clay minerals suggests that such processes must have played an important role as these materials moved from the relatively dilute solutions of the nonmarine environment to the relatively concentrated solution of sea water. The volumes of sea water sufficient to supply for sorption the amounts of most minor elements in the offshore marine samples are insignificant compared to the volumes of water with which the clay and organic matter were in contact during their transportation and sedimentation. Consequently, the chemical characteristics of the environment in which the clay minerals and organic matter accumulated and underwent diagenesis probably were the most important factors in controlling the degree to which sorption processes and the formation of syngenetic minerals affected the final composition of the rocks. ?? 1969.

Nearshore temperature findings for the Colorado River in Grand Canyon, Arizona: possible implications for native fish

USGS Publications Warehouse

Ross, Robert P.; Vernieu, William S.

2013-01-01

Since the completion of Glen Canyon Dam, Arizona, in 1963, downstream water temperatures in the main channel of the Colorado River in Glen, Marble, and Grand Canyons are much colder in summer. This has negatively affected humpback chub (Gila cypha) and other native fish adapted to seasonally warm water, reducing main-channel spawning activity and impeding the growth and development of larval and juvenile fish. Recently published studies by U.S. Geological Survey scientists found that under certain conditions some isolated nearshore environments in Grand Canyon allow water to become separated from the main-channel current and to warm, providing refuge areas for the development of larval and juvenile fish.

Diatom evidence for the onset of Pliocene cooling from AND-1B, McMurdo Sound, Antarctica

USGS Publications Warehouse

Riesselman, Christina; Dunbar, R. B.

2013-01-01

The late Pliocene, ~ 3.3–3.0 Ma, is the most recent interval of sustained global warmth in the geologic past. This window is the focus of climate reconstruction efforts by the U.S. Geological Survey's Pliocene Research, Interpretation, and Synoptic Mapping (PRISM) Data/Model Cooperative, and may provide a useful climate analog for the coming century. Reconstructions of past surface ocean conditions proximal to the Antarctic continent are essential to understanding the sensitivity of the cryosphere to this key interval in Earth's climate evolution. An exceptional marine sediment core collected from the southwestern Ross Sea (78° S), Antarctica, during ANDRILL's McMurdo Ice Shelf Project preserves evidence of dramatic fluctuations between grounded ice and productive, open ocean conditions during the late Pliocene, reflecting orbitally-paced glacial/interglacial cycling. In this near-shore record, diatom-rich sediments are recovered from interglacial intervals; two of these diatomites, from ~ 3.2 Ma and 3.03 Ma, are within the PRISM chronologic window. The diatom assemblages identified in PRISM-age late Pliocene diatom-rich sediments are distinct from those in mid-Pliocene and later Pliocene/Pleistocene intervals recovered from AND-1B, and comprise both extant taxa with well-constrained ecological preferences and a diverse extinct flora, some members of which are previously undescribed from Antarctic sediments. Both units are dominated by Chaetoceros resting spores, an indicator of high productivity and stratification that is present at much lower abundance in materials both older and younger than the PRISM-age sediments. Newly described species of the genus Fragilariopsis, which first appear in the AND-1B record at 3.2 Ma, are the most abundant extinct members of the PRISM-age assemblages. Other extant species with established environmental affinities, such as Fragilariopsis sublinearis, F. curta, Stellarima microtrias, and Thalassiothrix antarctica, are present at lower abundances. Environmental inferences drawn from extant diatom assemblages are in good agreement with those from Chaetoceros resting spores and the Fragilariopsis radiation. All three lines of evidence indicate the onset of late Pliocene cooling in the Ross Sea near-shore environment at 3.2 Ma, with intensification and possible regional persistence of summer sea ice by 3.03 Ma. An important implication of this research is the indication that the Ross Ice Shelf fluctuated dramatically on orbital timescales at a time when nearshore Antarctic conditions were only modestly warmer than present.

Spatial and temporal trends in Precambrian nitrogen cycling: A Mesoproterozoic offshore nitrate minimum

NASA Astrophysics Data System (ADS)

Koehler, Matthew C.; Stüeken, Eva E.; Kipp, Michael A.; Buick, Roger; Knoll, Andrew H.

2017-02-01

Fixed nitrogen is an essential nutrient for eukaryotes. As N2 fixation and assimilation of nitrate are catalyzed by metalloenzymes, it has been hypothesized that in Mesoproterozoic oceans nitrate was limited in offshore environments by low trace metal concentrations and high rates of denitrification in anoxic and episodically euxinic deep water masses, restricting eukaryotes to near-shore environments and limiting their evolutionary innovation. To date this hypothesis has only been tested in the Belt Supergroup (∼1.4 Ga), with results that support an onshore-offshore nitrate gradient as a potential control on eukaryote ecology. Here we present bulk nitrogen and organic carbon isotopic data from non-isochronous cross-basinal facies across the Bangemall (∼1.5 Ga) and the Roper (∼1.4-1.5 Ga) basins to better understand the extent and variability of onshore-offshore nitrogen isotope gradients in the Mesoproterozoic. Both basins show an average ∼1-2‰ enrichment in δ15Nbulk from deep to shallow facies, with a maximum range from -1‰ offshore to +7.5‰ onshore. Unlike the Belt basin, the Bangemall and Roper basins show some offshore δ15Nbulk values that are enriched beyond the isotopic range associated with biological N2 fixation alone. This suggests a mixture of aerobic and anaerobic metabolisms offshore. In shallow waters, where δ15Nbulk enrichment peaks, an aerobic nitrogen cycle was evidently operating. Even though isotopic signatures of aerobic nitrogen cycling are seen in all parts of the Bangemall and Roper basins, our data are consistent with a lateral gradient in nitrate availability within the photic zone, with higher concentrations in near-shore environments than offshore. The variability in δ15Nbulk values in each depositional environment and the consistently low δ15Nbulk values from Mesoproterozoic units compared to the Paleoproterozoic and Neoproterozoic suggest that nitrate concentrations in the global ocean were likely low. This trend is now seen in all three Mesoproterozoic basins so far examined, and contrasts with the Paleoproterozoic and Neoproterozoic where nearly all δ15Nbulk data plot above the N2 fixation window. Thus, we propose that the Mesoproterozoic ocean was characterized by a nitrate minimum, with the lowest concentrations in offshore environments. This inference is consistent with a Mesoproterozoic O2 decline following a temporary Paleoproterozoic O2 peak, and it further supports the idea that nitrate limitation offshore may have contributed to the restriction of photosynthetic eukaryotes to near-shore environments, delaying their rise to ecological dominance until the Neoproterozoic Era.

Nearshore distribution and abundance of Dungeness crabs in Glacier Bay National Park, Alaska

USGS Publications Warehouse

O'Clair, Charles E.; Freese, J. Lincoln; Stone, Robert P.; Shirley, Thomas C.; Leder, Erica H.; Taggart, S. James; Kruse, Gordon H.; Engstrom, Daniel R.

1995-01-01

As part of an ongoing, multi-agency study to determine the effects of closure of the commercial fishery for Dungeness crabs, Cancer magister, on crab population structure we examined patterns of distribution and abundance of crabs in nearshore habitats at five locations in and near Glacier Bay National Park. Sampling was conducted in April and September 1992 and April 1993 prior to the anticipated closure of the fishery in the park. Divers censused crabs by sex and reproductive state (ovigerous/nonovigerous females) along belt transects (2m x 100m) laid perpendicular to shore in the depth range 0 m (mean lower low water) to 18 m.Preliminary results from the first three sampling periods revealed that the average densities of Dungeness crabs at the five locations ranged from 78 to 2012 crabs/ha. Crab densities differed between populations depending on sex, reproductive state of females and sampling period. Male crabs showed reduced densities at Gustavus Flats in April 1992 (P<0.01) and 1993 (P<0.001). Ovigerous females had greater density at Bartlett Cove in April 1993 (P<0.001). Sex ratios were frequently skewed toward females. At Bartlett Cove and Gustavus Flats females outnumbered males in April 1992 and 1993 (P<0.001). Most of the females at Bartlett Cove and Gustavus Flats in April 1992 and 1993 were ovigerous (P-0.001). Males tended to occupy greater depths than females in April 1992 (P<0.05) but not April 1993 (P-005). The mean depth of males shifted from deeper to shallower water between April and September 1992 (P<0.001). The depth distribution of ovigerous crabs did not differ from that of nonovigerous female crabs. Future research prior to the anticipated closure of the commercial Dungeness crab fishery in Glacier Bay will include a tagging study to determine the extent of crab movement and further study of the temporal as well as the spatial variability observed in the structure of these populations.

Effects of warming, acidification, and reef-zone on the calcification of four Caribbean scleractinian corals of the Belize Barrier Reef System

NASA Astrophysics Data System (ADS)

Bove, C. B.; Ries, J. B.; Davies, S. W.; Westfield, I. T.; Castillo, K.

2016-02-01

Rising atmospheric carbon dioxide (pCO2) has caused ocean temperature to increase and ocean pH to decrease, raising concerns about the health of marine organisms. Previous studies have shown that corals are particularly vulnerable to these stressors, most likely due to their narrow thermal tolerance and use of carbonate ions in calcification, although response patterns vary across taxa. We conducted laboratory experiments for 95 days to investigate the independent and interactive effects of ocean warming (28, 31 °C) and acidification on the calcification rate and skeletal properties of four abundant and ubiquitously distributed Caribbean coral species (Pseudodiploria strigosa, Siderastrea siderea, Porites astreoides, Undaria tenuifolia) collected from nearshore and forereef environments of the Belize Barrier Reef. Aragonite saturation states of 3.9, 3.2, 2.2, and 0.7, constrained by total alkalinity measured via closed-cell potentiometric titration and dissolved inorganic carbon measured via coulometry, were attained by sparging natural seawater with air-CO2 mixtures formulated at 280, 400, 700, and 2800 ppmv pCO2, respectively. Temperature and pCO2 were fully crossed (N=3 tanks per treatment) and corals were gradually exposed to treatment conditions over a 30-day period, followed by an additional 30-day acclimation. Rates of linear skeletal extension were measured relative to a calcein spike emplaced in the coral skeletons at the start of the experiment, and net calcification rates were determined from coral buoyant weights obtained every 30 days. Initial results show that corals in all treatments continued to calcify on a net basis, however, the effect of warming on net calcification rates of P. asteroids and U. tenuifolia became more negative at lower saturation states. In addition, nearshore U. tenuifolia calcified faster than forereef conspecifics in all treatments.

Pumping Iron and Silica Bodybuilding

NASA Astrophysics Data System (ADS)

Mcnair, H.; Brzezinski, M. A.; Krause, J. W.; Parker, C.; Brown, M.; Coale, T.; Bruland, K. W.

2016-02-01

The availability of dissolved iron influences the stoichiometry of nutrient uptake by diatoms. Under nutrient replete conditions diatoms consume silicic acid and nitrate in a 1:1 ratio, this ratio increases under iron stress. Using the tracers 32Si and PDMPO, the total community and group-specific silica production rates were measured along a gradient of dissolved iron in an upwelling plume off the California coast. At each station, a control (ambient silicic acid) and +20 µM silicic acid treatment were conducted with each tracer to determine whether silicic acid limitation controlled the rate of silica production. Dissolved iron was 1.3 nmol kg-1 nearshore and decreased to 0.15 nmol kg-1 offshore. Silicic acid decreased more rapidly than nitrate, it was nearly 9 µM higher in the nearshore and 7 µM lower than nitrate in the middle of the transect where the iron concentration had decreased. The rate of diatom silica production decreased in tandem with silicic acid concentration, and silica production limitation by low silicic acid was most pronounced when iron concentrations were >0.4 nmol kg-1. The composition of the diatom assemblage shifted from Chaetoceros spp. dominated nearshore to a more sparse pennate-dominated assemblage offshore. Changes in taxa-specific silica production rates will be reported based on examination of PDMPO labeled cells using confocal microscopy.

The effect of bathymetric filtering on nearshore process model results

USGS Publications Warehouse

Plant, N.G.; Edwards, K.L.; Kaihatu, J.M.; Veeramony, J.; Hsu, L.; Holland, K.T.

2009-01-01

Nearshore wave and flow model results are shown to exhibit a strong sensitivity to the resolution of the input bathymetry. In this analysis, bathymetric resolution was varied by applying smoothing filters to high-resolution survey data to produce a number of bathymetric grid surfaces. We demonstrate that the sensitivity of model-predicted wave height and flow to variations in bathymetric resolution had different characteristics. Wave height predictions were most sensitive to resolution of cross-shore variability associated with the structure of nearshore sandbars. Flow predictions were most sensitive to the resolution of intermediate scale alongshore variability associated with the prominent sandbar rhythmicity. Flow sensitivity increased in cases where a sandbar was closer to shore and shallower. Perhaps the most surprising implication of these results is that the interpolation and smoothing of bathymetric data could be optimized differently for the wave and flow models. We show that errors between observed and modeled flow and wave heights are well predicted by comparing model simulation results using progressively filtered bathymetry to results from the highest resolution simulation. The damage done by over smoothing or inadequate sampling can therefore be estimated using model simulations. We conclude that the ability to quantify prediction errors will be useful for supporting future data assimilation efforts that require this information.

A system for measuring bottom profile, waves and currents in the high-energy nearshore environment

USGS Publications Warehouse

Sallenger, A.H.; Howard, P.C.; Fletcher, C. H.; Howd, P.A.

1983-01-01

A new data-acquisition system capable of measuring waves, currents and the nearshore profile in breaking waves as high as 5 m has been developed and successfully field-tested. Components of the mechanical system are a sled carrying a vertical mast, a double-drum winch placed landward of the beach, and a line that runs from one drum of the winch around three blocks, which are the corners of a right triangle, to the other drum of the winch. The sled is attached to the shore-normal side of the triangular line arrangement and is pulled offshore by one drum of the winch and onshore by the other. The profile is measured as the sled is towed along the shore-normal transect using an infrared rangefinder mounted landward of the winch and optical prisms mounted on top of the sled's mast. A pressure sensor and two-axis electromagnetic current meter are mounted on the frame of the sled. These data are encoded on the sled and telemetered to a receiving/recording station onshore. Preliminary results suggest that near-bottom offshore-flowing currents during periods of high-energy swell are important in forcing changes to the configuration of the nearshore profile. ?? 1983.

Abundance and Genetic Diversity of Aerobic Anoxygenic Phototrophic Bacteria of Coastal Regions of the Pacific Ocean

PubMed Central

Ritchie, Anna E.

2012-01-01

Aerobic anoxygenic phototrophic (AAP) bacteria are photoheterotrophic microbes that are found in a broad range of aquatic environments. Although potentially significant to the microbial ecology and biogeochemistry of marine ecosystems, their abundance and genetic diversity and the environmental variables that regulate these properties are poorly understood. Using samples along nearshore/offshore transects from five disparate islands in the Pacific Ocean (Oahu, Molokai, Futuna, Aniwa, and Lord Howe) and off California, we show that AAP bacteria, as quantified by the pufM gene biomarker, are most abundant near shore and in areas with high chlorophyll or Synechococcus abundance. These AAP bacterial populations are genetically diverse, with most members belonging to the alpha- or gammaproteobacterial groups and with subclades that are associated with specific environmental variables. The genetic diversity of AAP bacteria is structured along the nearshore/offshore transects in relation to environmental variables, and uncultured pufM gene libraries suggest that nearshore communities are distinct from those offshore. AAP bacterial communities are also genetically distinct between islands, such that the stations that are most distantly separated are the most genetically distinct. Together, these results demonstrate that environmental variables regulate both the abundance and diversity of AAP bacteria but that endemism may also be a contributing factor in structuring these communities. PMID:22307290

Application of the marine Ex-Bz transient system for delineating near shore resistive targets

NASA Astrophysics Data System (ADS)

Levi, Eldad; Goldman, Mark

2017-09-01

Under certain conditions, multidimensional coastal effect significantly enhances relative target response of the broadside transient marine Ex-Bz system. The effect is caused by a redistribution of the induced currents between the resistive target and the sea bottom compared to that existing in a 1-D geometry. As a result, the effect strongly depends on specific geoelectric conditions in the near-shore environment. The first study of the effect in the Mediterranean coast of central Israel was addressing shallow groundwater problem under specific geoelectric, hydrogeological and geomorphological conditions. Under different conditions (e.g. deep targets and sharp near-shore bathymetry), the influence of the effect on target response might be significantly different. More general analysis carried out in this study comprises various geoelectric scenarios that include both shallow and deep resistive targets at different distances from the shore line as well as various geometries of the target and the near-shore bathymetry. The study includes three major exploration aspects of the system, namely signal detectability, lateral and vertical resolution. Taking into account poor lateral resolution of the classical frequency domain CSEM and the limited application in shallow sea, the described broadside transient Ex-Bz system might represent a desired alternative for delineating shallow and deep resistive targets in transition zone.

Development of MODIS data-based algorithm for retrieving sea surface temperature in coastal waters.

PubMed

Wang, Jiao; Deng, Zhiqiang

2017-06-01

A new algorithm was developed for retrieving sea surface temperature (SST) in coastal waters using satellite remote sensing data from Moderate Resolution Imaging Spectroradiometer (MODIS) aboard Aqua platform. The new SST algorithm was trained using the Artificial Neural Network (ANN) method and tested using 8 years of remote sensing data from MODIS Aqua sensor and in situ sensing data from the US coastal waters in Louisiana, Texas, Florida, California, and New Jersey. The ANN algorithm could be utilized to map SST in both deep offshore and particularly shallow nearshore waters at the high spatial resolution of 1 km, greatly expanding the coverage of remote sensing-based SST data from offshore waters to nearshore waters. Applications of the ANN algorithm require only the remotely sensed reflectance values from the two MODIS Aqua thermal bands 31 and 32 as input data. Application results indicated that the ANN algorithm was able to explaining 82-90% variations in observed SST in US coastal waters. While the algorithm is generally applicable to the retrieval of SST, it works best for nearshore waters where important coastal resources are located and existing algorithms are either not applicable or do not work well, making the new ANN-based SST algorithm unique and particularly useful to coastal resource management.

Large-Scale Spatial Distribution Patterns of Echinoderms in Nearshore Rocky Habitats

PubMed Central

Iken, Katrin; Konar, Brenda; Benedetti-Cecchi, Lisandro; Cruz-Motta, Juan José; Knowlton, Ann; Pohle, Gerhard; Mead, Angela; Miloslavich, Patricia; Wong, Melisa; Trott, Thomas; Mieszkowska, Nova; Riosmena-Rodriguez, Rafael; Airoldi, Laura; Kimani, Edward; Shirayama, Yoshihisa; Fraschetti, Simonetta; Ortiz-Touzet, Manuel; Silva, Angelica

2010-01-01

This study examined echinoderm assemblages from nearshore rocky habitats for large-scale distribution patterns with specific emphasis on identifying latitudinal trends and large regional hotspots. Echinoderms were sampled from 76 globally-distributed sites within 12 ecoregions, following the standardized sampling protocol of the Census of Marine Life NaGISA project (www.nagisa.coml.org). Sample-based species richness was overall low (<1–5 species per site), with a total of 32 asteroid, 18 echinoid, 21 ophiuroid, and 15 holothuroid species. Abundance and species richness in intertidal assemblages sampled with visual methods (organisms >2 cm in 1 m2 quadrats) was highest in the Caribbean ecoregions and echinoids dominated these assemblages with an average of 5 ind m−2. In contrast, intertidal echinoderm assemblages collected from clearings of 0.0625 m2 quadrats had the highest abundance and richness in the Northeast Pacific ecoregions where asteroids and holothurians dominated with an average of 14 ind 0.0625 m−2. Distinct latitudinal trends existed for abundance and richness in intertidal assemblages with declines from peaks at high northern latitudes. No latitudinal trends were found for subtidal echinoderm assemblages with either sampling technique. Latitudinal gradients appear to be superseded by regional diversity hotspots. In these hotspots echinoderm assemblages may be driven by local and regional processes, such as overall productivity and evolutionary history. We also tested a set of 14 environmental variables (six natural and eight anthropogenic) as potential drivers of echinoderm assemblages by ecoregions. The natural variables of salinity, sea-surface temperature, chlorophyll a, and primary productivity were strongly correlated with echinoderm assemblages; the anthropogenic variables of inorganic pollution and nutrient contamination also contributed to correlations. Our results indicate that nearshore echinoderm assemblages appear to be shaped by a network of environmental and ecological processes, and by the differing responses of various echinoderm taxa, making generalizations about the patterns of nearshore rocky habitat echinoderm assemblages difficult. PMID:21079760

Large-scale spatial distribution patterns of echinoderms in nearshore rocky habitats.

PubMed

Iken, Katrin; Konar, Brenda; Benedetti-Cecchi, Lisandro; Cruz-Motta, Juan José; Knowlton, Ann; Pohle, Gerhard; Mead, Angela; Miloslavich, Patricia; Wong, Melisa; Trott, Thomas; Mieszkowska, Nova; Riosmena-Rodriguez, Rafael; Airoldi, Laura; Kimani, Edward; Shirayama, Yoshihisa; Fraschetti, Simonetta; Ortiz-Touzet, Manuel; Silva, Angelica

2010-11-05

This study examined echinoderm assemblages from nearshore rocky habitats for large-scale distribution patterns with specific emphasis on identifying latitudinal trends and large regional hotspots. Echinoderms were sampled from 76 globally-distributed sites within 12 ecoregions, following the standardized sampling protocol of the Census of Marine Life NaGISA project (www.nagisa.coml.org). Sample-based species richness was overall low (<1-5 species per site), with a total of 32 asteroid, 18 echinoid, 21 ophiuroid, and 15 holothuroid species. Abundance and species richness in intertidal assemblages sampled with visual methods (organisms >2 cm in 1 m(2) quadrats) was highest in the Caribbean ecoregions and echinoids dominated these assemblages with an average of 5 ind m(-2). In contrast, intertidal echinoderm assemblages collected from clearings of 0.0625 m(2) quadrats had the highest abundance and richness in the Northeast Pacific ecoregions where asteroids and holothurians dominated with an average of 14 ind 0.0625 m(-2). Distinct latitudinal trends existed for abundance and richness in intertidal assemblages with declines from peaks at high northern latitudes. No latitudinal trends were found for subtidal echinoderm assemblages with either sampling technique. Latitudinal gradients appear to be superseded by regional diversity hotspots. In these hotspots echinoderm assemblages may be driven by local and regional processes, such as overall productivity and evolutionary history. We also tested a set of 14 environmental variables (six natural and eight anthropogenic) as potential drivers of echinoderm assemblages by ecoregions. The natural variables of salinity, sea-surface temperature, chlorophyll a, and primary productivity were strongly correlated with echinoderm assemblages; the anthropogenic variables of inorganic pollution and nutrient contamination also contributed to correlations. Our results indicate that nearshore echinoderm assemblages appear to be shaped by a network of environmental and ecological processes, and by the differing responses of various echinoderm taxa, making generalizations about the patterns of nearshore rocky habitat echinoderm assemblages difficult.

Numerical experiments on breaking waves on contrasting beaches using a two-phase flow approach

NASA Astrophysics Data System (ADS)

Bakhtyar, R.; Barry, D. A.; Kees, C. E.

2012-11-01

A mechanistic understanding of beach environments needs to account for interactions of oceanic forcing and beach materials, in particular the role of waves on the evolution of the beach profile. A fully coupled two-phase flow model was used to simulate nearshore fluid-sediment turbulent flow in the cross-shore direction. It includes the Reynolds-Averaged Navier-Stokes equations and turbulent stress closures for each phase, and accounts for inter-granular stresses. The model has previously been validated using laboratory-scale data, so the results are likely more reliable for that scale. It was used to simulate wave breaking and the ensuing hydrodynamics and sediment transport processes in the surf/swash zones. Numerical experiments were conducted to investigate the effects of varying beach and wave characteristics (e.g., beach slope, sediment grain size, wave periods and heights) on the foreshore profile changes. Spilling and plunging breakers occur on dissipative and intermediate beaches, respectively. The impact of these wave/beach types on nearshore zone hydrodynamics and beach morphology was determined. The numerical results showed that turbulent kinetic energy, sediment concentrations and transport rate are greater on intermediate than on dissipative beaches. The results confirmed that wave energy, beach grain size and bed slope are main factors for sediment transport and beach morphodynamics. The location of the maximum sediment transport is near the breaking point for both beach types. Coarse- and fine-sand beaches differ significantly in their erosive characteristics (e.g., foreshore profile evolutions are erosive and accretionary on the fine and coarse sand beaches, respectively). In addition, a new parameter (based on main driving factors) is proposed that can characterize the sediment transport in the surf and swash zones. The results are consistent with existing physical observations, suggesting that the two-phase flow model is suitable for the simulation of hyper-concentrated mixed water-sediment flows in the nearshore. The model thus has potential as a useful tool for investigating interactions between nearshore hydrodynamics and beach morphology.

Analysis of the impacts of Wave Energy Converter arrays on the nearshore wave climate in the Pacific Northwest

NASA Astrophysics Data System (ADS)

O'Dea, A.; Haller, M. C.

2013-12-01

As concerns over the use of fossil fuels increase, more and more effort is being put into the search for renewable and reliable sources of energy. Developments in ocean technologies have made the extraction of wave energy a promising alternative. Commercial exploitation of wave energy would require the deployment of arrays of Wave Energy Converters (WECs) that include several to hundreds of individual devices. Interactions between WECs and ocean waves result in both near-field and far-field changes in the incident wave field, including a significant decrease in wave height and a redirection of waves in the lee of the array, referred to as the wave shadow. Nearshore wave height and direction are directly related to the wave radiation stresses that drive longshore currents, rip currents and nearshore sediment transport, which suggests that significant far-field changes in the wave field due to WEC arrays could have an impact on littoral processes. The goal of this study is to investigate the changes in nearshore wave conditions and radiation stress forcing as a result of an offshore array of point-absorber type WECs using a nested SWAN model, and to determine how array size, configuration, spacing and distance from shore influence these changes. The two sites of interest are the Northwest National Marine Renewable Energy Center (NNMREC) test sites off the coast of Newport Oregon, the North Energy Test Site (NETS) and the South Energy Test Site (SETS). NETS and SETS are permitted wave energy test sites located approximately 4 km and 10 km offshore, respectively. Twenty array configurations are simulated, including 5, 10, 25, 50 and 100 devices in two and three staggered rows in both closely spaced (three times the WEC diameter) and widely spaced (ten times the WEC diameter) arrays. Daily offshore wave spectra are obtained from a regional WAVEWATCH III hindcast for 2011, which are then propagated across the continental shelf using SWAN. Arrays are represented in SWAN through the external modification of the wave spectra at the device locations, based on a new experimentally determined Power Transfer Function established in an earlier WEC-array laboratory study. Changes in nearshore forcing conditions for each array size and configuration are compared in order to determine the scale of the far-field effects of WEC arrays and which array sizes and configurations could have the most significant impacts on coastal processes.

Spatial variations in δ13C and δ15N values of primary consumers in a coastal lagoon

NASA Astrophysics Data System (ADS)

Como, S.; Magni, P.; Van Der Velde, G.; Blok, F. S.; Van De Steeg, M. F. M.

2012-12-01

The analysis of the contribution of a food source to a consumer's diet or the trophic position of a consumer is highly sensitive to the variability of the isotopic values used as input data. However, little is known in coastal lagoons about the spatial variations in the isotopic values of primary consumers considered 'end members' in the isotope mixing models for quantifying the diet of secondary consumers or as a baseline for estimating the trophic position of consumers higher up in the food web. We studied the spatial variations in the δ13C and δ15N values of primary consumers and sedimentary organic matter (SOM) within a selected area of the Cabras lagoon (Sardinia, Italy). Our aim was to assess how much of the spatial variation in isotopic values of primary consumers was due to the spatial variability between sites and how much was due to differences in short distances from the shore. Samples were collected at four stations (50-100 m apart) selected randomly at two sites (1.5-2 km apart) chosen randomly at two distances from the shore (i.e. in proximity of the shore -Nearshore - and about 200 m away from the shore -Offshore). The sampling was repeated in March, May and August 2006 using new sites at the two chosen distances from the shore on each date. The isotopic values of size-fractionated seston and macrophytes were also analyzed as a complementary characterization of the study area. While δ15N did not show any spatial variations, the δ13C values of deposit feeders, Alitta (=Neanthes) succinea, Lekanesphaera hookeri, Hydrobia acuta and Gammarus aequicauda, were more depleted Offshore than Nearshore. For these species, there were significant effects of distance or distance × dates in the mean δ13C values, irrespective of the intrinsic variation between sites. SOM showed similar spatial variations in δ13C values, with Nearshore-Offshore differences up to 6‰. This indicates that the spatial isotopic changes are transferred from the food sources to the deposit feeders studied. In contrast, δ13C and δ15N values of suspension feeders, Ficopomatus enigmaticus and Amphibalanus amphitrite, did not show major variations, either between sites, or between Nearshore and Offshore. These different patterns between deposit feeders and suspension feeders are probably due to a weaker trophic link of the latter with SOM. We suggest that the Nearshore-Offshore gradient might be an important source of isotopic variation that needs to be considered in future web studies in coastal lagoons.

Influence of the sea-ice edge on the Arctic nearshore environment

NASA Astrophysics Data System (ADS)

Barnhart, K. R.; Overeem, I.; Anderson, R. S.

2013-12-01

Coasts form the dynamic interface of the terrestrial and oceanic systems. In the Arctic, and in much of the world, the coast is a zone of relatively high population, infrastructure, biodiversity, and ecosystem services. A significant difference between Arctic and temperate coasts is the presence of sea ice. Sea ice influences Arctic coasts in two main ways: (1) the length of the sea ice-free season controls the length of time over which nearshore water can interact with the land, and (2) the sea ice edge controls the fetch over which storm winds can blow over open water, resulting in changes in nearshore water level and wave field. The resulting nearshore hydrodynamic environment impacts all aspects of the coastal system. Here, we use satellite records of sea ice along with a simple model for wind-driven storm surge and waves to document how changes in the length and character of the sea ice-free season have impacted the nearshore hydrodynamic environment. For our sea ice analysis we primarily use the Bootstrap Sea Ice Concentrations from Nimbus-7 SMMR and DMSP SSM/I-SSMIS. We make whole-Arctic maps of sea ice change in the coastal zone. In addition to evaluating changes in length of the sea ice-free season at the coast, we look at changes segmented by azimuth. This allows us to consider changes in the sea ice in the context of the wind field. For our storm surge and wave field analysis we focus on the Beaufort Sea region. This region has experienced some of the greatest changes in both sea ice cover and coastal erosion rates in the Arctic and is anticipated to experience significant change in the future. In addition, the NOAA ESRL GMD has observed the wind field at Barrow since extends to 1977. In our past work on the rapid and accelerating coastal erosion, we have shown that one may model storm surge with a 2D numerical bathystrophic model, and that waves are well represented by the Shore Protection Manual methods for shallow-water fetch-limited waves. We use these models to explore the effect of increasing fetch on water level set up and wave generation. As increasing the fetch is one of the main effects of the changing sea ice cover, this allows us to connect changes in the sea ice cover to changes in the nearshore hydrodynamic environment. The long wind record allows for us to investigate changes in extreme wind and associated storm events. Preliminary analysis of Barrow and Drew Point indicate that at Drew Point the sea ice-free season has expanded by ˜17 days/decade while at Barrow it has expanded by ˜22 days/decade. We find the increase in the number of days when the sea ice edge is far away from the coast makes up a large proportion of the total increase in the duration of the sea ice-free season. For these days the sea ice edge does not provide a limit on the fetch over which water level set up and waves are generated.

Carbonate-shelf depositional environments of the Ordovician Viola formation in South-Central Kansas

USGS Publications Warehouse

Newell, K.D.

2000-01-01

The Upper Ordovician Viola Formation, an important petroleum reservoir in the Midcontinent, is a carbonate unit present over much of the subsurface in Kansas. The Viola is composed of two fining-upward sedimentary packages that are separated from each other by a minor karstic surface representing a brief period of exposure. Each package represents a third-order sedimentary cycle and consists of an echinoderm-rich packstone overlain by a thicker lime mudstone. The echinoderm-rich packstone was deposited nearshore in agitated waters, but subsequently was bioturbated. The overlying lime mudstone was deposited in deeper, quiet waters, and locally contains storm-deposited carbonate sands. Subtle growth of the Central Kansas Arch and Pratt Anticline (structures transecting the depositional shelf) is indicated by packstones and grainstones being thicker over these arches, whereas finer grained lithologies dominate in basinal areas on the arch flanks. Structureless lime mudstones, probably intensely bioturbated, grade into laminated lime mudstones farther basinward.

Multiscale analysis of restoration priorities for marine shoreline planning.

PubMed

Diefenderfer, Heida L; Sobocinski, Kathryn L; Thom, Ronald M; May, Christopher W; Borde, Amy B; Southard, Susan L; Vavrinec, John; Sather, Nichole K

2009-10-01

Planners are being called on to prioritize marine shorelines for conservation status and restoration action. This study documents an approach to determining the management strategy most likely to succeed based on current conditions at local and landscape scales. The conceptual framework based in restoration ecology pairs appropriate restoration strategies with sites based on the likelihood of producing long-term resilience given the condition of ecosystem structures and processes at three scales: the shorezone unit (site), the drift cell reach (nearshore marine landscape), and the watershed (terrestrial landscape). The analysis is structured by a conceptual ecosystem model that identifies anthropogenic impacts on targeted ecosystem functions. A scoring system, weighted by geomorphic class, is applied to available spatial data for indicators of stress and function using geographic information systems. This planning tool augments other approaches to prioritizing restoration, including historical conditions and change analysis and ecosystem valuation.

Proposed 10 MWe OTEC pilot plant for the Commonwealth of the Northern Mariana Islands

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

Dunbar, L.E.; Chan, G.L.

1981-01-01

A preliminary conceptual design of a 10 MWe OTEC pilot plant has been proposed for the island of Saipan in the Commonwealth of the Northern Mariana Islands. This unique small OTEC plant is intended as a prototype for commercial plants in the small Pacific Island territories and nations. The system concept minimizes local construction to accommodate a lack of local skilled labor and facilities. The baseline design is a concrete barge-mounted plant built in Portland, Oregon, towed to Saipan, and permanently anchored in near-shore shallow water. Details of key subsystem design features are provided including a bottom-mounted cold water pipe,more » modular power subsystem, and wave shield for storm protection. The results of economic analyses are presented to illustrate the cost competitiveness of electricity from the OTEC plant compared to the current oil-fired diesel units in Saipan.« less

Proposed 10 MWe OTEC pilot plant for the Commonwealth of the Northern Mariana Islands

NASA Astrophysics Data System (ADS)

Dunbar, L. E.; Chan, G. L.

1981-12-01

A preliminary conceptual design of a 10 MWe OTEC pilot plant has been proposed for the island of Saipan in the Commonwealth of the Northern Mariana Islands. This unique small OTEC plant is intended as a prototype for commercial plants in the small Pacific Island territories and nations. The system concept minimizes local construction to accommodate a lack of local skilled labor and facilities. The baseline design is a concrete barge-mounted plant built in Portland, Oregon, towed to Saipan, and permanently anchored in near-shore shallow water. Details of key subsystem design features are provided including a bottom-mounted cold water pipe, modular power subsystem, and wave shield for storm protection. The results of economic analyses are presented to illustrate the cost competitiveness of electricity from the OTEC plant compared to the current oil-fired diesel units in Saipan.

California coast nearshore processes study

NASA Technical Reports Server (NTRS)

Pirie, D. M. (Principal Investigator)

1972-01-01

The author has identified the following significant results. In the Santa Barbara Channel the effect of the California and the Anacapa Currents are clearly seen in image 1109-18073M. The large triangular shaped lobe of suspended particulate matter that stretches almost to Anacapa Island from the Ventura River area is disrupted approximately midchannel by the east-moving Anacapa Current. In the Point Conception area a lobe of suspended material approximately 20 miles long can be seen moving eastward as a result of the California Current. In the San Francisco Bay area the major results include the detection and delineation of the San Francisco Bay, the location and vector of suspended sediment in the San Francisco Bay, and the ability to differentiate morphologic units within the San Francisco Bay tidelands. Several densitometer line traces seaward of the Golden Gate Bridge on image 1075-18173-4 outline the San Francisco Bay and give evidence of good water penetration.

The epiphytic microbiota of the globally widespread macroalga Cladophora glomerata (Chlorophyta, Cladophorales).

PubMed

Zulkifly, Shahrizim; Hanshew, Alissa; Young, Erica B; Lee, Philip; Graham, Melissa E; Graham, Michael E; Piotrowski, Michael; Graham, Linda E

2012-09-01

The filamentous chlorophyte Cladophora produces abundant nearshore populations in marine and freshwaters worldwide, often dominating periphyton communities and producing nuisance growths under eutrophic conditions. High surface area and environmental persistence foster such high functional and taxonomic diversity of epiphytic microfauna and microalgae that Cladophora has been labeled an ecological engineer. We tested the hypotheses that (1) Cladophora supports a structurally and functionally diverse epiphytic prokaryotic microbiota that influences materials cycling and (2) mutualistic host-microbe interactions occur. Because previous molecular sequencing-based analyses of the microbiota of C. glomerata found as western Lake Michigan beach drift had identified pathogenic associates such as Escherichia coli, we also asked if actively growing lentic C. glomerata harbors known pathogens. We used 16S rRNA gene amplicon pyrosequencing to examine the microbiota of C. glomerata of Lake Mendota, Dane, Wisconsin, United States, during the growing season of 2011, at the genus- or species-level to infer functional phenotypes. We used correlative scanning electron and fluorescence microscopy to describe major prokaryotic morphotypes. We found microscopic evidence for diverse bacterial morphotypes, and molecular evidence for ca. 100 distinct sequence types classifiable to genus at the 80% confidence level or species at the 96-97% level within nine bacterial phyla, but not E. coli or related human pathogens. We inferred that bacterial epiphytes of lentic C. glomerata have diverse functions in materials cycling, with traits that indicate the occurrence of mutualistic interactions with the algal host.

Introduction to "northern Gulf of Mexico ecosystem change and hazards susceptibility"

USGS Publications Warehouse

Brock, J.C.; Lavoie, D.L.; Poore, R.Z.

2009-01-01

The northern Gulf of Mexico and its diverse natural resources are threatened by population and development pressure, and by the impacts of rising sea level and severe storms. In the wake of the devastating 2005 hurricane season, and in response to the complex management issues facing the region, the U.S. Geological Survey organized the multidisciplinary "Northern Gulf of Mexico Ecosystem Change and Hazards Susceptibility" project. This special issue of Geo-Marine Letters hosts a few of the early results in the form of 11 papers covering three themes: (1) the control exerted by the underlying geologic framework on geomorphology and nearshore processes and features; (2) impact of human activities on nearshore water quality; and (3) hurricanes and associated effects. ?? 2009 US Government.

LANDSAT survey of near-shore ice conditions along the Arctic coast of Alaska

NASA Technical Reports Server (NTRS)

Stringer, W. J. (Principal Investigator); Barrett, S. A.

1978-01-01

The author has identified the following significant results. Winter and spring near-shore ice conditions were analyzed for the Beaufort Sea 1973-77, and the Chukchi Sea 1973-76. LANDSAT imagery was utilized to map major ice features related to regional ice morphology. Significant features from individual LANDSAT image maps were combined to yield regional maps of major ice ridge systems for each year of study and maps of flaw lead systems for representative seasons during each year. These regional maps were, in turn, used to prepare seasonal ice morphology maps. These maps showed, in terms of a zonal analysis, regions of statistically uniform ice behavior. The behavioral characteristics of each zone were described in terms of coastal processes and bathymetric configuration.

Historic and current use of Lower Cook Inlet, Alaska, by Belugas, Delphinapterus leucas

USGS Publications Warehouse

Speckman, Suzann G.; Piatt, John F.

2000-01-01

Dedicated at-sea surveys for marine birds and mammals conducted in lower Cook Inlet in late July and early August from 1995–99 failed to locate any belugas, Delphinapterus leucas. Surveys covered a total of 6,249 linear km and were conducted in both nearshore and offshore habitats. Sightings included 791 individual marine mammals of 10 species. Both historical data and local knowledge indicate that belugas were regularly seen in summer in nearshore and offshore areas of lower Cook Inlet up until the early 1990’s. Diminished presence of belugas in lower Cook Inlet may be a direct function of reduced numbers but may also indicate changes in habitat quality that may inhibit recovery.

California State Waters Map Series: offshore of Refugio Beach, California

USGS Publications Warehouse

Johnson, Samuel Y.; Dartnell, Peter; Cochrane, Guy R.; Golden, Nadine E.; Phillips, Eleyne L.; Ritchie, Andrew C.; Krigsman, Lisa M.; Dieter, Bryan E.; Conrad, James E.; Greene, H. Gary; Seitz, Gordon G.; Endris, Charles A.; Sliter, Ray W.; Wong, Florence L.; Erdey, Mercedes D.; Gutierrez, Carlos I.; Yoklavich, Mary M.; East, Amy E.; Hart, Patrick E.; Johnson, Samuel Y.; Cochran, Susan A.

2015-01-01

Seafloor habitats in the broad Santa Barbara Channel region consist of significant amounts of soft, unconsolidated sediment interspersed with isolated areas of rocky habitat that support kelp-forest communities nearshore and rocky-reef communities in deep water. The potential marine benthic habitat types mapped in the Offshore of Refugio Beach map area are directly related to its Quaternary geologic history, geomorphology, and active sedimentary processes. These potential habitats, which lie primarily within the Shelf (continental shelf) but also partly within the Flank (basin flank or continental slope) megahabitats, primarily are composed of soft sediment interrupted by a few carbonate mounds. This homogeneous seafloor of sediment and low-relief bedrock provides promising habitat for groundfish, crabs, shrimp, and other marine benthic organisms.

Review of information bearing upon the conservation and protection of humpback whales in hawaii. Final report

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

Tinney, R.T.

1988-03-01

Humpback whales wintering in Hawaii may be affected by human activities in the nearshore waters apparently favored by the whales. The report reviews available information on the number, age/sex composition, reproductive status, distribution, movements, and essential habitats of the whales in Hawaii. It then identifies human activities that may be affecting the whales or their habitats and describes their nature, magnitude, and significance. This is followed by: a review of existing local, state, and Federal laws and regulations and their adequacy for avoiding or mitigating the effects of human activities on the whales; an identification of critical information gaps regardingmore » the whales and the human activities.« less

Parallel Evolution of Two Clades of an Atlantic-Endemic Pathogenic Lineage of Vibrio parahaemolyticus by Independent Acquisition of Related Pathogenicity Islands

PubMed Central

Xu, Feng; Drees, Kevin P.; Sebra, Robert P.; Jones, Stephen H.

2017-01-01

ABSTRACT Shellfish-transmitted Vibrio parahaemolyticus infections have recently increased from locations with historically low disease incidence, such as the Northeast United States. This change coincided with a bacterial population shift toward human-pathogenic variants occurring in part through the introduction of several Pacific native lineages (ST36, ST43, and ST636) to nearshore areas off the Atlantic coast of the Northeast United States. Concomitantly, ST631 emerged as a major endemic pathogen. Phylogenetic trees of clinical and environmental isolates indicated that two clades diverged from a common ST631 ancestor, and in each of these clades, a human-pathogenic variant evolved independently through acquisition of distinct Vibrio pathogenicity islands (VPaI). These VPaI differ from each other and bear little resemblance to hemolysin-containing VPaI from isolates of the pandemic clonal complex. Clade I ST631 isolates either harbored no hemolysins or contained a chromosome I-inserted island we call VPaIβ that encodes a type 3 secretion system (T3SS2β) typical of Trh hemolysin producers. The more clinically prevalent and clonal ST631 clade II had an island we call VPaIγ that encodes both tdh and trh and that was inserted in chromosome II. VPaIγ was derived from VPaIβ but with some additional acquired elements in common with VPaI carried by pandemic isolates, exemplifying the mosaic nature of pathogenicity islands. Genomics comparisons and amplicon assays identified VPaIγ-type islands containing tdh inserted adjacent to the ure cluster in the three introduced Pacific and most other emergent lineages that collectively cause 67% of infections in the Northeast United States as of 2016. IMPORTANCE The availability of three different hemolysin genotypes in the ST631 lineage provided a unique opportunity to employ genome comparisons to further our understanding of the processes underlying pathogen evolution. The fact that two different pathogenic clades arose in parallel from the same potentially benign lineage by independent VPaI acquisition is surprising considering the historically low prevalence of community members harboring VPaI in waters along the Northeast U.S. coast that could serve as the source of this material. This illustrates a possible predisposition of some lineages to not only acquire foreign DNA but also become human pathogens. Whereas the underlying cause for the expansion of V. parahaemolyticus lineages harboring VPaIγ along the U.S. Atlantic coast and spread of this element to multiple lineages that underlies disease emergence is not known, this work underscores the need to define the environment factors that favor bacteria harboring VPaI in locations of emergent disease. PMID:28687650

Multi-Disciplinary Approach to Trace Contamination of Streams and Beaches

USGS Publications Warehouse

Nickles, James

2008-01-01

Concentrations of fecal-indicator bacteria in urban streams and ocean beaches in and around Santa Barbara occasionally can exceed public-health standards for recreation. The U.S. Geological Survey (USGS), working with the City of Santa Barbara, has used multi-disciplinary science to trace the sources of the bacteria. This research is helping local agencies take steps to improve recreational water quality. The USGS used an approach that combined traditional hydrologic and microbiological data, with state-of-the-art genetic, molecular, and chemical tracer analysis. This research integrated physical data on streamflow, ground water, and near-shore oceanography, and made extensive use of modern geophysical and isotopic techniques. Using those techniques, the USGS was able to evaluate the movement of water and the exchange of ground water with near-shore ocean water. The USGS has found that most fecal bacteria in the urban streams came from storm-drain discharges, with the highest concentrations occurring during storm flow. During low streamflow, the concentrations varied as much as three-fold, owing to variable contribution of non-point sources such as outdoor water use and urban runoff to streamflow. Fecal indicator bacteria along ocean beaches were from both stream discharge to the ocean and from non-point sources such as bird fecal material that accumulates in kelp and sand at the high-tide line. Low levels of human-specific Bacteroides, suggesting fecal material from a human source, were consistently detected on area beaches. One potential source, a local sewer line buried beneath the beach, was found not to be responsible for the fecal bacteria.

Occurrence of Escherichia coli and Enterococci in Cladophora (Chlorophyta) in Nearshore Water and Beach Sand of Lake Michigan†

PubMed Central

Whitman, Richard L.; Shively, Dawn A.; Pawlik, Heather; Nevers, Meredith B.; Byappanahalli, Muruleedhara N.

2003-01-01

Each summer, the nuisance green alga Cladophora (mostly Cladophora glomerata) amasses along Lake Michigan beaches, creating nearshore anoxia and unsightly, malodorous mats that can attract problem animals and detract from visitor enjoyment. Traditionally, elevated counts of Escherichia coli are presumed to indicate the presence of sewage, mostly derived from nearby point sources. The relationship between fecal indicator bacteria and Cladophora remains essentially unstudied. This investigation describes the local and regional density of Escherichia coli and enterococci in Cladophora mats along beaches in the four states (Wisconsin, Illinois, Indiana, and Michigan) bordering Lake Michigan. Samples of Cladophora strands collected from 10 beaches (n = 41) were assayed for concentrations of E. coli and enterococci during the summer of 2002. Both E. coli and enterococci were ubiquitous (up to 97% occurrence), with overall log mean densities (± standard errors) of 5.3 (± 4.8) and 4.8 (± 4.5) per g (dry weight). E. coli and enterococci were strongly correlated in southern Lake Michigan beaches (P < 0.001, R2 = 0.73, n = 17) but not in northern beaches (P = 0.892, n = 16). Both E. coli and enterococci survived for over 6 months in sun-dried Cladophora mats stored at 4°C; the residual bacteria in the dried alga readily grew upon rehydration. These findings suggest that Cladophora amassing along the beaches of Lake Michigan may be an important environmental source of indicator bacteria and call into question the reliability of E. coli and enterococci as indicators of water quality for freshwater recreational beaches. PMID:12902262

Occurrence of Escherichia coli and enterococci in Cladophora (Chlorophyta) in nearshore water and beach sand of Lake Michigan.

PubMed

Whitman, Richard L; Shively, Dawn A; Pawlik, Heather; Nevers, Meredith B; Byappanahalli, Muruleedhara N

2003-08-01

Each summer, the nuisance green alga Cladophora (mostly Cladophora glomerata) amasses along Lake Michigan beaches, creating nearshore anoxia and unsightly, malodorous mats that can attract problem animals and detract from visitor enjoyment. Traditionally, elevated counts of Escherichia coli are presumed to indicate the presence of sewage, mostly derived from nearby point sources. The relationship between fecal indicator bacteria and Cladophora remains essentially unstudied. This investigation describes the local and regional density of Escherichia coli and enterococci in Cladophora mats along beaches in the four states (Wisconsin, Illinois, Indiana, and Michigan) bordering Lake Michigan. Samples of Cladophora strands collected from 10 beaches (n = 41) were assayed for concentrations of E. coli and enterococci during the summer of 2002. Both E. coli and enterococci were ubiquitous (up to 97% occurrence), with overall log mean densities (+/- standard errors) of 5.3 (+/- 4.8) and 4.8 (+/- 4.5) per g (dry weight). E. coli and enterococci were strongly correlated in southern Lake Michigan beaches (P < 0.001, R(2) = 0.73, n = 17) but not in northern beaches (P = 0.892, n = 16). Both E. coli and enterococci survived for over 6 months in sun-dried Cladophora mats stored at 4 degrees C; the residual bacteria in the dried alga readily grew upon rehydration. These findings suggest that Cladophora amassing along the beaches of Lake Michigan may be an important environmental source of indicator bacteria and call into question the reliability of E. coli and enterococci as indicators of water quality for freshwater recreational beaches.

Occurrence of Escherichia coli and enterococci in Cladophora (Clorophyta) in nearshore water and beach sand of Lake Michigan

USGS Publications Warehouse

Whitman, Richard L.; Shively, Dawn A.; Pawlik, Heather; Nevers, Meredith B.; Byappanahalli, Muruleedhara N.

2003-01-01

Each summer, the nuisance green alga Cladophora (mostly Cladophora glomerata) amasses along Lake Michigan beaches, creating nearshore anoxia and unsightly, malodorous mats that can attract problem animals and detract from visitor enjoyment. Traditionally, elevated counts of Escherichia coli are presumed to indicate the presence of sewage, mostly derived from nearby point sources. The relationship between fecal indicator bacteria and Cladophora remains essentially unstudied. This investigation describes the local and regional density of Escherichia coli and enterococci in Cladophora mats along beaches in the four states (Wisconsin, Illinois, Indiana, and Michigan) bordering Lake Michigan. Samples of Cladophora strands collected from 10 beaches (n = 41) were assayed for concentrations of E. coli and enterococci during the summer of 2002. Both E. coli and enterococci were ubiquitous (up to 97% occurrence), with overall log mean densities (± standard errors) of 5.3 (± 4.8) and 4.8 (± 4.5) per g (dry weight). E. coli and enterococci were strongly correlated in southern Lake Michigan beaches (P R2 = 0.73, n = 17) but not in northern beaches (P = 0.892, n = 16). Both E. coli and enterococci survived for over 6 months in sun-dried Cladophora mats stored at 4°C; the residual bacteria in the dried alga readily grew upon rehydration. These findings suggest that Cladophora amassing along the beaches of Lake Michigan may be an important environmental source of indicator bacteria and call into question the reliability of E. coli and enterococci as indicators of water quality for freshwater recreational beaches.

The Manciano Sandstone: a shoreface deposit of Miocene basins of the Northern Apennines, Italy

NASA Astrophysics Data System (ADS)

Martini, I. P.; Cascella, A.; Rau, A.

1995-09-01

Well exposed, diamond-line cut, quarry-exposures of the Manciano Sandstone allow a detailed analysis of sandy, fossiliferous, nearshore deposits of the shelf of the Northern Apennines. The Manciano Sandstone is characterized by medium to very coarse, washed, fairly well sorted, lithic sandstone, with thin interlayers of sandy conglomerates. It displays two principal, rhythmically alternating sandy facies: (a) slightly burrowed (mostly Macaronichnus, Ophiomorpha, Skolithos) units, trough cross-bedded, locally showing possible tidal bundles with few whole Scutella (echinoid) shells reworked on foresets, or occasional large-scale (approximately 2 m) planar cross-bedded, bar-accretion units; and (b) slightly finer, darker-coloured reddish-brown sandstone units, heavily bioturbated ( Cruziana-Skolithos) ichnofauna) representing slightly more sheltered settings. Large oysters are present in near-living position in a few thin layers and, more commonly, as reworked, comminuted fragments in sandy layers. Many calcareous pebbles and oyster fragments are bored. Other fossils consist of echinoids ( Scutella), some balanids and reworked foraminifera and bryozoa. The Manciano sands were deposited primarily in a wave-dominated shoreface, containing migrating bars/ridges and affected by wave-induced, possibly tidal-enhanced currents. This tidal influence confirms the opening of the Miocene Apenninic Sea to oceans, both the developing Atlantic Ocean to the west and, through a long, narrow seaway, the Asian portion of the Tethys Sea to the east.

Towards the Adriatic meteotsunami early warning system: modelling strategy and validation

NASA Astrophysics Data System (ADS)

Denamiel, Clea; Šepić, Jadranka; Vilibić, Ivica

2017-04-01

Destructive meteotsunamis are known to occur along the eastern Adriatic coastal areas and islands (Vilibić and Šepić, 2009). The temporal lag between the offshore generation of meteotsunamis due to specific atmospheric conditions and the arrival of a dangerous nearshore propagating wave at known locations is of the order of tens of minutes to a couple of hours. In order to reduce the coastal risk for the coastal communities, an early warning system must rely on the ability to detect these extreme storms offshore with in-situ measurements and to predict the hydrodynamic response nearshore via numerical models within this short time lag. However, the numerical modelling of meteotsunamis requires both temporal and spatial high-resolution atmospheric and ocean models which are highly demanding concerning time and computer resources. Furthermore, both a multi-model approach and an ensemble modelling strategy should be used to better forecast the distribution of the nearshore impact of meteotsunamis. The modelling strategy used in this study thus rely on the development of an operational atmosphere-ocean model of the Adriatic Sea at 1km spatial resolution based on the state-of-the-art fully coupled COAWST model (Warner et al., 2010). The model allows for generation of meteotsunamis offshore, while various high-resolution (up to 5m) nearshore hydrodynamic models (such as ADCIRC - Luettich and Westerink, 1991; SELFE - Zhang et al., 2008 and GeoClaw - LeVeque, 2012) are setup to properly reproduce meteotsunami dynamics of the entire Croatian coastal areas, which are characterized by a great number of islands, channels and bays. The implementation and validation of each component of this modelling system is first undertaken for the well documented meteotsunami event (Šepić et al., 2016), which was recorded along the Croatian Adriatic coast on the 25th and the 26th of June 2014. The validation of the modelling strategy as well as the model results is presented and discussed in this study. LeVeque, R.J., 2002. Finite Volume Methods for Hyperbolic Problems. Cambridge University Press. Luettich, R.A., and Westerink, J.J., 1991. A solution for the vertical variation of stress, rather than velocity, in a three-dimensional circulation model. International Journal for Numerical Methods in Fluids, 12, 911-928. Šepić, J., Međogorac, I., Janeković, I., Dunić, N., and Vilibić, I., 2016. Multi-Meteotsunami Event in the Adriatic Sea Generated by Atmospheric Disturbances of 25-26 June 2014. Pure and Applied Geophysics, DOI 10.1007/s00024-016-1249-4. Vilibić, I., Šepić, J., 2009. Destructive meteotsunamis along the eastern Adriatic coast: overview. Physics and Chemistry of the Earth, 34, 904-917. Warner, J.C., Armstrong, B., He, R.Y., and Zambon, J.B., 2010. Development of a coupled ocean-atmosphere-wave-sediment transport (COAWST) modeling System. Ocean Modelling, 35(3), 230-244. Zhang, Y.J., and Baptista, A.M., 2008. SELFE: A semi-implicit Eulerian-Langrangian finite-element model for cross-scale ocean circulation. Ocean Modelling, 21, 71-96.

Forcing a three-dimensional, hydrostatic, primitive-equation model for application in the surf zone: 2. Application to DUCK94

NASA Astrophysics Data System (ADS)

Newberger, P. A.; Allen, J. S.

2007-08-01

A three-dimensional primitive-equation model for application to the nearshore surf zone has been developed. This model, an extension of the Princeton Ocean Model (POM), predicts the wave-averaged circulation forced by breaking waves. All of the features of the original POM are retained in the extended model so that applications can be made to regions where breaking waves, stratification, rotation, and wind stress make significant contributions to the flow behavior. In this study we examine the effects of breaking waves and wind stress. The nearshore POM circulation model is embedded within the NearCom community model and is coupled with a wave model. This combined modeling system is applied to the nearshore surf zone off Duck, North Carolina, during the DUCK94 field experiment of October 1994. Model results are compared to observations from this experiment, and the effects of parameter choices are examined. A process study examining the effects of tidal depth variation on depth-dependent wave-averaged currents is carried out. With identical offshore wave conditions and model parameters, the strength and spatial structure of the undertow and of the alongshore current vary systematically with water depth. Some three-dimensional solutions show the development of shear instabilities of the alongshore current. Inclusion of wave-current interactions makes an appreciable difference in the characteristics of the instability.

Wave Dissipation over Nearshore Beach Morphology: Insights from High-Resolution LIDAR Observations and the SWASH Wave Model

NASA Astrophysics Data System (ADS)

Mulligan, R. P.; Gomes, E.; McNinch, J.; Brodie, K. L.

2016-02-01

Numerical modelling of the nearshore zone can be computationally intensive due to the complexity of wave breaking, and the need for high temporal and spatial resolution. In this study we apply the SWASH non-hydrostatic wave-flow model that phase-resolves the free surface and fluid motions in the water column at high resolution. The model is forced using observed directional energy spectra, and results are compared to wave observations during moderate storm events. Observations are collected outside the surf zone using acoustic wave and currents sensors, and inside the surf zone over a 100 m transect using high-resolution LIDAR measurements of the sea surface from a sensor mounted on a tower on the beach dune at the Field Research Facility in Duck, NC. The model is applied to four cases with different wave conditions and bathymetry, and used to predict the spatial variability in wave breaking, and correlation between energy dissipation and morphologic features. Model results compare well with observations of spectral evolution outside the surf zone, and with the remotely sensed observations of wave transformation inside the surf zone. The results indicate the importance of nearshore bars, rip-channels, and larger features (major scour depression under the pier following large waves from Hurricane Irene) on the location of wave breaking and alongshore variability in wave energy dissipation.

Principal sources and dispersal patterns of suspended particulate matter in nearshore surface waters of the northeast Pacific Ocean. [California coastal waters

NASA Technical Reports Server (NTRS)

Carlson, P. R. (Principal Investigator); Janda, R. J.

1973-01-01

The author has identified the following significant results. Release-recovery paths of drift cards released in conjunction with ERTS-1 overflight show that nearshore surface currents along the central and northern California coast flowed southward at an average rate in excess of 10 cm/sec (8.5 km/day) during August and September 1973 (California Current). By the middle of October 1973, the nearshore surface currents had reversed and the dominant flow velocity was northward at an average rate in excess of 20 cm/sec (17 km/ day) (Davidson Current). The August-September data suggested the presence of counterclockwise gyres in Monterey Bay and the Gulf of the Farallones, but by the middle of October, the gyres were no longer evident. Imagery of April 1973 showed well developed plumes of suspended sediment in Monterey Bay from the Salinas River and in the Gulf of the Farallones from San Francisco Bay. ERTS-1 imagery provides an effective means of monitoring timber harvest in the redwood forest along the northern California coast. ERTS-1 imagery also clearly portrays contrasting topographic belts characterized by fluvial erosion and by mass movement. The most visually apparent and most persistent river mouth suspended sediment plumes are associated with those rivers that drain belts of topography that appear to have been eroded primarily by mass movement.

Distribution and abundance of larval fish in the nearshore waters of western Lake Huron

USGS Publications Warehouse

O'Gorman, Robert

1983-01-01

Ichthyoplankton was collected at 17 nearshore (bottom depth ≥5 m but ≤10 m) sites in western Lake Huron during 1973–75 with a 0.5-m net of 351-micron mesh towed at 99 m/min. Larvae of rainbow smelt (Osmerus mordax) dominated late spring and early summer catches and larvae of alewives (Alosa pseudoharengus) the midsummer catches. Larval yellow perch (Perca flavescens) were caught in early summer but were rarely the dominant species. The time of spawning and hatching, and thus occurrence of larvae, differed between areas but was less variable for alewives than for yellow perch. The appearance of larvae in Saginaw Bay was followed successively by their appearance in southern, central, and northern Lake Huron. Rainbow smelt were most abundant in northern Lake Huron and yellow perch and alewives in inner Saginaw Bay. Densities of either rainbow smelt or alewives occasionally exceeded 1/m3, whereas those of yellow perch never exceeded 0.1/m3. Abundance of alewives was usually highest 1 to 3 m beneath the surface and that of rainbow smelt 2 to at least 6 m beneath the surface. Important nursery areas of rainbow smelt were in bays and off irregular coastlines and those of yellow perch were in bays. All nearshore waters seemed equally important as nursery areas of alewives.

Spatial patterns in PCB concentrations of Lake Michigan lake trout

USGS Publications Warehouse

Madenjian, Charles P.; DeSorcie, Timothy J.; Stedman, Ralph M.; Brown, Edward H.; Eck, Gary W.; Schmidt, Larry J.; Hesselberg, Robert J.; Chernyak, Sergei M.; Passino-Reader, Dora R.

1999-01-01

Most of the PCB body burden in lake trout (Salvelinus namaycush) of the Great Lakes is from their food. PCB concentrations were determined in lake trout from three different locations in Lake Michigan during 1994–1995, and lake trout diets were analyzed at all three locations. The PCB concentrations were also determined in alewife (Alosa pseudoharengus), rainbow smelt (Osmerus mordax), bloater (Coregonus hoyi), slimy sculpin (Cottus cognatus), and deepwater sculpin (Myoxocephalus thompsoni), five species of prey fish eaten by lake trout in Lake Michigan, at three nearshore sites in the lake. Despite the lack of significant differences in the PCB concentrations of alewife, rainbow smelt, bloater, slimy sculpin, and deepwater sculpin from the southeastern nearshore site near Saugatuck (Michigan) compared with the corresponding PCB concentrations from the northwestern nearshore site near Sturgeon Bay (Wisconsin), PCB concentrations in lake trout at Saugatuck were significantly higher than those at Sturgeon Bay. The difference in the lake trout PCB concentrations between Saugatuck and Sturgeon Bay could be explained by diet differences. The diet of lake trout at Saugatuck was more concentrated in PCBs than the diet of Sturgeon Bay lake trout, and therefore lake trout at Saugatuck were more contaminated in PCBs than Sturgeon Bay lake trout. These findings were useful in interpreting the long-term monitoring series for contaminants in lake trout at both Saugatuck and the Wisconsin side of the lake.

Changes in forage fish community indicated by the diet of the Brandt's cormorant (Phalacrocorax penicillatus) in the central California Current

NASA Astrophysics Data System (ADS)

Elliott, Meredith L.; Bradley, Russell W.; Robinette, Dan P.; Jahncke, Jaime

2015-06-01

The population, productivity and diet of two Brandt's cormorant (Phalacrocorax penicillatus) colonies located in the central California Current were compared. The offshore colony on Southeast Farallon Island has experienced a declining population over time and anomalously low productivity in recent years. The nearshore colony near Point Arguello has been increasing and its productivity has remained stable. The diets of cormorants at the two colonies elucidated by analysis of regurgitated pellets, while different, have shown similar decreases in the consumption of northern anchovy (Engraulis mordax) since 2008, followed by increased consumption of rockfish (Sebastes spp.) and flatfish (order Pleuronectiformes). By using the diet results from another seabird nesting in central California, the rhinoceros auklet (Cerorhinca monocerata), and one from which whole fish can be obtained, we found that the rockfish species assemblage has changed with offshore rockfish species decreasing while nearshore ones have increased. This change in the rockfish species has negatively impacted Brandt's cormorants at the offshore colony by forcing them to make longer foraging trips to meet energy needs of themselves and their chicks; this has led to low breeding success and a declining population at this site. On the other hand, the nearshore colony has abundant nearby food resources, and it has prospered. These results underscore the value of using seabird data from multiple colonies to better understand changes occurring in the marine environment.

Molecular typing of Escherichia coli strains associated with threatened sea ducks and near-shore marine habitats of south-west Alaska

USGS Publications Warehouse

Hollmén, Tuula E.; DebRoy, Chitrita; Flint, Paul L.; Safine, David E.; Schamber, Jason L.; Riddle, Ann E.; Trust, Kimberly A.

2011-01-01

In Alaska, sea ducks winter in coastal habitats at remote, non-industrialized areas, as well as in proximity to human communities and industrial activity. We evaluated prevalence and characteristics of Escherichia coli strains in faecal samples of Steller's eiders (Polysticta stelleri; n = 122) and harlequin ducks (Histrionicus histrionicus; n = 21) at an industrialized site and Steller's eiders (n = 48) at a reference site, and compared these strains with those isolated from water samples from near-shore habitats of ducks. The overall prevalence of E. coli was 16% and 67% in Steller's eiders and harlequin ducks, respectively, at the industrialized study site, and 2% in Steller's eiders at the reference site. Based on O and H antigen subtyping and genetic characterization by enterobacterial repetitive intergenic consensus polymerase chain reaction and pulsed-field gel electrophoresis, we found evidence of avian pathogenic E. coli (APEC) strains associated with both species and detected E. coli strains carrying virulence genes associated with mammals in harlequin ducks. Steller's eiders that carried APEC had lower serum total protein and albumin concentrations, providing further evidence of pathogenicity. The genetic profile of two E. coli strains from water matched an isolate from a Steller's eider providing evidence of transmission between near-shore habitats and birds.

The biological assessment of flora and fauna as standards for changes in the near-shore ocean environment: a study of Barbers Point Harbor.

PubMed

Hokama, Y; Wachi, K M; Shiraki, A; Goo, C; Ebesu, J S

2001-02-01

The biological assessments of the flora and fauna in the near-shore ocean environment, specifically Barbers Point Harbor (BPH), demonstrate the usefulness of these biological analyses for evaluation of the changes occurring following man-made excavation for expansion of the harbor. The study included identification and enumeration of macroalgae and dinoflagellates and analyses of herbivores and carnivores in four areas within the perimeter of the harbor and the north and south entrances into the harbor. Numbers of macroalgae varied between 1994 and 1999 surveys, with significant decrease in numbers in stations C, D and E. Stations A and B were similar between 1994 and 1999 with a slight increase in 1999. The significant differences were shown with the appearance of Gambierdiscus toxicus (G toxicus) in 1999 among the algae in stations A and B. Assessment of herbivores and carnivores with the immunological membrane immunobead assay using monoclonal antibody to ciguatoxin and related polyethers demonstrated an increase in fish toxicity among the herbivore from 1994-1999 (22% increase) with a decrease (22%) in non-toxic fish. This was also demonstrated in the carnivores, but to a lesser degree. It is suggested that the biological analyses of the flora and the fauna of the near-shore ocean environment are appropriate to assess the changes that occur from natural and man-made alterations.

Molecular typing of Escherichia coli strains associated with threatened sea ducks and near-shore marine habitats of south-west Alaska.

PubMed

Hollmén, Tuula E; Debroy, Chitrita; Flint, Paul L; Safine, David E; Schamber, Jason L; Riddle, Ann E; Trust, Kimberly A

2011-04-01

In Alaska, sea ducks winter in coastal habitats at remote, non-industrialized areas, as well as in proximity to human communities and industrial activity. We evaluated prevalence and characteristics of Escherichia coli strains in faecal samples of Steller's eiders (Polysticta stelleri; n = 122) and harlequin ducks (Histrionicus histrionicus; n = 21) at an industrialized site and Steller's eiders (n = 48) at a reference site, and compared these strains with those isolated from water samples from near-shore habitats of ducks. The overall prevalence of E. coli was 16% and 67% in Steller's eiders and harlequin ducks, respectively, at the industrialized study site, and 2% in Steller's eiders at the reference site. Based on O and H antigen subtyping and genetic characterization by enterobacterial repetitive intergenic consensus polymerase chain reaction and pulsed-field gel electrophoresis, we found evidence of avian pathogenic E. coli (APEC) strains associated with both species and detected E. coli strains carrying virulence genes associated with mammals in harlequin ducks. Steller's eiders that carried APEC had lower serum total protein and albumin concentrations, providing further evidence of pathogenicity. The genetic profile of two E. coli strains from water matched an isolate from a Steller's eider providing evidence of transmission between near-shore habitats and birds. © 2010 Society for Applied Microbiology and Blackwell Publishing Ltd.

Beach boundary layer: a framework for addressing recreational water quality impairment at enclosed beaches.

PubMed

Grant, Stanley B; Sanders, Brett F

2010-12-01

Nearshore waters in bays, harbors, and estuaries are frequently contaminated with human pathogens and fecal indicator bacteria. Tracking down and mitigating this contamination is complicated by the many point and nonpoint sources of fecal pollution that can degrade water quality along the shore. From a survey of the published literature, we propose a conceptual and mathematical framework, the "beach boundary layer model", for understanding and quantifying the relative impact of beach-side and bay-side sources of fecal pollution on nearshore water quality. In the model, bacterial concentration in ankle depth water C(ankle) [bacteria L(-3)] depends on the flux m'' [bacteria L(-2) T(-1)] of fecal bacteria from beach-side sources (bather shedding, bird and dog feces, tidal washing of sediments, decaying vegetation, runoff from small drains, and shallow groundwater discharge), a cross-shore mass transfer velocity k [L T(-1)] that accounts for the physics of nearshore transport and mixing, and a background concentration C(bay) [bacteria L(-3)] attributable to bay-side sources of pollution that impact water quality over large regions (sewage outfalls, creeks and rivers): C(ankle) = m''/k + C(bay). We demonstrate the utility of the model for identifying risk factors and pollution sources likely to impact shoreline water quality, and evaluate the model's underlying assumptions using computational fluid dynamic simulations of flow, turbulence, and mass transport in a trapezoidal channel.

Rivermouth alteration of agricultural impacts on consumer tissue δ15N

USGS Publications Warehouse

Larson, James H.; Richardson, William B.; Vallazza, Jonathan M.; Nelson, J. C.

2013-01-01

Terrestrial agricultural activities strongly influence riverine nitrogen (N) dynamics, which is reflected in the δ15N of riverine consumer tissues. However, processes within aquatic ecosystems also influence consumer tissue δ15N. As aquatic processes become more important terrestrial inputs may become a weaker predictor of consumer tissue δ15N. In a previous study, this terrestrial-consumer tissue δ15N connection was very strong at river sites, but was disrupted by processes occurring in rivermouths (the ‘rivermouth effect’). This suggested that watershed indicators of N loading might be accurate in riverine settings, but could be inaccurate when considering N loading to the nearshore of large lakes and oceans. In this study, the rivermouth effect was examined on twenty-five sites spread across the Laurentian Great Lakes. Relationships between agriculture and consumer tissue δ15N occurred in both upstream rivers and at the outlets where rivermouths connect to the nearshore zone, but agriculture explained less variation and had a weaker effect at the outlet. These results suggest that rivermouths may sometimes be significant sources or sinks of N, which would cause N loading estimates to the nearshore zone that are typically made at discharge gages further upstream to be inaccurate. Identifying definitively the controls over the rivermouth effect on N loading (and other nutrients) will require integration of biogeochemical and hydrologic models.

Mapping, classification, and spatial variation of hardbottom habitats in the northeastern Gulf of Mexico

NASA Astrophysics Data System (ADS)

Kingon, Kelly

This dissertation starts by evaluating the applicability of using a commercially available, cost-effective, sidescan sonar system to detect benthic habitats, in particular hardbottom habitats, in the nearshore northeastern Gulf of Mexico. To illustrate the capability of low-cost devices in mapping benthic habitats, I tested the Humminbird 997c SI unit marketed to fishermen at a cost of approximately 2,000. Methodological approaches to effectively capture and process the Humminbird sidescan imagery were developed. Humminbird sidescan data from three sites were compared to overlapping sidescan imagery acquired by the National Marine Fisheries Service using a standard, much more expensive (˜20,000) Marine Sonic system. This analysis verified that the classification results of sand and hardbottom habitats based on data collected using the Humminbird sidescan system were similar to those produced using the traditional and more expensive Marine Sonic sidescan equipment. Thirty-three sites in total were then mapped with the Humminbird system and sampled using dive surveys. Seascape pattern metrics were calculated from the classified Humminbird sidescan maps. The dive survey data included measurements of the geomorphology, physical attributes of the water column (e.g. temperature, depth, and visibility), and coverage and heights of the benthic biota. The coverage and heights of the biota were compared to the geomorphology, seascape, and water column variables to identify patterns in the distribution and community composition of the sessile organisms. Within the study area, visibility was found to vary with longitude. Sites in the east showed higher visibility than sites in the west and this may be driving the community patterns that were identified. Relationships were identified between the four most abundant taxa (sponges, hard corals, brown algae, and red algae) and the geomorphology, physical, and seascape variables. However, the relationships were often complicated and the biota did not strictly follow gradients or boundaries in substrate or geoform (physical feature or landform), even though these features are often used to classify habitats and biotopes. The percent cover of rock was a significant geomorphology variable for red algae and hard coral coverage while geoforms were related to the heights of sponges and brown algae. Seascape metrics also had significant effects on the sessile biota particularly related to patch edges, heterogeneity, core areas, nearest neighbor distances, and the percent cover of hardbottom. Despite the fact that sessile organisms do not move much, if at all following their planktonic larval stage, the surrounding seascape contributes to the patterns we see in their distribution, coverage, and heights. The third chapter focuses on applying a new classification standard to the benthic habitats in the nearshore northeastern Gulf of Mexico. The United States Geological Survey (USGS) has a standardized system for classifying terrestrial and aquatic habitats found across the U.S. which has been in place for almost 40 years. This classification standard does not include marine and most coastal habitats. Therefore, marine researchers developed a number of classification systems for coastal and marine habitats relevant to their local or regional studies in U.S. waters. A national standardized method for classifying marine and coastal habitats was not adopted until recently. The Coastal and Marine Ecological Classification Standard (CMECS) developed by the Federal Geographic Data Committee was approved last year and is intended to fill the gap in U.S. marine habitat classification standards. Since the classification standard is in its infancy, it has not been applied in many geographic areas. My third chapter is the first study to apply the CMECS to the benthic habitats in the nearshore northeastern Gulf of Mexico off the coast of northwest Florida. Hardbottom and sand habitats are characteristic of this area. In the previous chapter, the underwater surveys revealed that the dominant taxa at the sites within the study area were hard corals, sponges, and macroalgae. I used CMECS to broadly classify the sites where the surveys were completed. I found that habitat heterogeneity and a wide variety of environmental characteristics influenced the distribution of taxa at the local scale. This made applying CMECS at scales finer than the composite study area unfeasible without major modifications. CMECS worked well for classifying the broad scale in this region but was not appropriate for classifying complex fine-scale biotopes. (Abstract shortened by UMI.)

Process based modeling of total longshore sediment transport

USGS Publications Warehouse

Haas, K.A.; Hanes, D.M.

2004-01-01

Waves, currents, and longshore sand transport are calculated locally as a function of position in the nearshore region using process based numerical models. The resultant longshore sand transport is then integrated across the nearshore to provide predictions of the total longshore transport of sand due to waves and longshore currents. Model results are in close agreement with the I1-P1 correlation described by Komar and Inman (1970) and the CERC (1984) formula. Model results also indicate that the proportionality constant in the I1-P1 formula depends weakly upon the sediment size, the shape of the beach profile, and the particular local sediment flux formula that is employed. Model results indicate that the various effects and influences of sediment size tend to cancel out, resulting in little overall dependence on sediment size.

Influence of San Gabriel submarine canyon on narrow-shelf sediment dynamics, southern California

USGS Publications Warehouse

Karl, Herman A.

1980-01-01

A conceptual model attributes the PTC to modification of shelf circulation patterns by San Gabriel Canyon. Surface waves diverge over the canyon head resulting in differential wave set up at the shore face. This forces back turbid nearshore water for a distance of a few kilometers toward the canyon. At some point on the shelf, seaward nearshore flow overlaps offshore currents generated or modified by internal waves focused onto the shelf by the canyon and/or turbulent eddies produced by flow separation in currents moving across the canyon axis. At times, these subtle processes overprint tidal and wind-driven currents and thereby create the PTC. The model suggests that canyons heading several kilometers from shore can have a regulatory effect on narrow-shelf sediment dynamics.

Investigating Storm-Induced Total Water Levels on Complex Barred Beaches

NASA Astrophysics Data System (ADS)

Cohn, N.; Ruggiero, P.; Walstra, D.

2013-12-01

Water levels in coastal environments are not static, but rather vary from a range of factors including mean sea level, tides, storm surge, and wave runup. Cumulatively these superimposed factors determine the total water level (TWL), the extent of which has major implications for coastal erosion and inundation during periods of high energy. Storm-induced, super-elevated water levels pose a threat to low lying coastal regions, as clearly demonstrated by recent events such as Hurricanes Sandy and Katrina. For this reason, the ability to accurately predict the TWL is crucial for both emergency managers and coastal planners. While some components of TWL are well understood (e.g., tides) there is still significant uncertainty in predicting runup, a process that can be a major contributor to instantaneous TWLs. Traditionally, empirical relationships derived from observational field data have been used to estimate runup, including wave setup and both incident and infragravity swash (Stockdon et al., 2006). While these formulations have shown skill in predicting the runup extent on natural beaches, these equations consider only the most basic contributing factors - namely the mean foreshore beach slope, the offshore wave height, and offshore wave period. Not included in these empirical estimates is the role of nearshore morphology on TWLs. However, it has long been recognized that nearshore sandbars act as natural barriers to coastal erosion during storm events by dissipating wave energy far from the beach face. Nonetheless, the influence of nearshore morphology on inner surf zone processes, including wave runup, is poorly understood. Recent pioneering studies (eg., Soldini et al., 2013 and Stephens et al., 2011) have explored the role of simple nearshore features (single Gaussian bars) on swash processes. Many locations in the world, however, are characterized by more complex morphologies such as multiple barred systems. Further, in many such places, including Columbia River Littoral Cell (USA), Duck, NC (USA), Hasaki (Japan), and the Netherlands, a net offshore bar migration (NOM) cycle has been observed whereby bars migrate seaward across the surf zone and decay offshore on interannual cycles. Depending on the stage of the cycle, the number and configuration of the bars may differ widely. For example in the Columbia River Littoral Cell there are typically 2 to 4 nearshore bars. In 1999, the outermost bar crest was located in a water depth of 6.5 m (relative to MLLW) while in 2009 it was located only in 3 m of water. Such large differences in nearshore morphology clearly influence wave breaking patterns and have the potential for influencing the corresponding wave runup as well. Here we apply a numerical, short-wave averaged yet long-wave resolving, non-linear hydrodynamic model (XBeach) to investigate the role that real world (non-synthetic), complex morphologies exert on TWLs. Model simulations under moderate to extreme wave forcing conditions are being used to develop relationships between offshore wave conditions, bar configuration, and runup extent. Additionally, we are exploring how, under the same wave conditions, a particular location may be more vulnerable to flooding simply based on the stage of the NOM cycle. Comparisons with the Stockdon et al. (2006) runup equation will be made to assess traditional empirical approaches relative to model predictions.

Observations of storm morphodynamics using Coastal Lidar and Radar Imaging System (CLARIS): Importance of wave refraction and dissipation over complex surf-zone morphology at a shoreline erosional hotspot

NASA Astrophysics Data System (ADS)

Brodie, Katherine L.

Elevated water levels and large waves during storms cause beach erosion, overwash, and coastal flooding, particularly along barrier island coastlines. While predictions of storm tracks have greatly improved over the last decade, predictions of maximum water levels and variations in the extent of damage along a coastline need improvement. In particular, physics based models still cannot explain why some regions along a relatively straight coastline may experience significant erosion and overwash during a storm, while nearby locations remain seemingly unchanged. Correct predictions of both the timing of erosion and variations in the magnitude of erosion along the coast will be useful to both emergency managers and homeowners preparing for an approaching storm. Unfortunately, research on the impact of a storm to the beach has mainly been derived from "pre" and "post" storm surveys of beach topography and nearshore bathymetry during calm conditions. This has created a lack of data during storms from which to ground-truth model predictions and test hypotheses that explain variations in erosion along a coastline. We have developed Coastal Lidar and Radar Imaging System (CLARIS), a mobile system that combines a terrestrial scanning laser and an X-band marine radar system using precise motion and location information. CLARIS can operate during storms, measuring beach topography, nearshore bathymetry (from radar-derived wave speed measurements), surf-zone wave parameters, and maximum water levels remotely. In this dissertation, we present details on the development, design, and testing of CLARIS and then use CLARIS to observe a 10 km section of coastline in Kitty Hawk and Kill Devil Hills on the Outer Banks of North Carolina every 12 hours during a Nor'Easter (peak wave height in 8 m of water depth = 3.4 m). High decadal rates of shoreline change as well as heightened erosion during storms have previously been documented to occur within the field site. In addition, complex bathymetric features that traverse the surf-zone into the nearshore are present along the southern six kilometers of the field site. In addition to the CLARIS observations, we model wave propagation over the complex nearshore bathymetry for the same storm event. Data reveal that the complex nearshore bathymetry is mirrored by kilometer scale undulations in the shoreline, and that both morphologies persist during storms, contrary to common observations of shoreline and surf-zone linearization by large storm waves. We hypothesize that wave refraction over the complex nearshore bathymetry forces flow patterns which may enhance or stabilize the shoreline and surf-zone morphology during storms. In addition, our semi-daily surveys of the beach indicate that spatial and temporal patterns of erosion are strongly correlated to the steepness of the waves. Along more than half the study site, fifty percent or more of the erosion that occurred during the first 12 hours of the storm was recovered within 24 hours of the peak of the storm as waves remained large (>2.5 m), but transitioned to long period swell. In addition, spatial variations in the amount of beach volume change during the building portion of the storm were strongly correlated with observed wave dissipation within the inner surf zone, as opposed to predicted inundation elevations or alongshore variations in wave height.

White Lake AOC Habitat Restoration Project

EPA Pesticide Factsheets

The Muskegon Conservation District and the White Lake Public Advisory Council in 2012 completed the White Lake AOC Shoreline Habitat Restoration Project to address the loss of shoreline and nearshore habitat.

Evaluating the potential for near-shore bathymetry on the Majuro Atoll, Republic of the Marshall Islands, using Landsat 8 and WorldView-3 imagery

USGS Publications Warehouse

Poppenga, Sandra K.; Palaseanu-Lovejoy, Monica; Gesch, Dean B.; Danielson, Jeffrey J.; Tyler, Dean J.

2018-04-16

Satellite-derived near-shore bathymetry (SDB) is becoming an increasingly important method for assessing vulnerability to climate change and natural hazards in low-lying atolls of the northern tropical Pacific Ocean. Satellite imagery has become a cost-effective means for mapping near-shore bathymetry because ships cannot collect soundings safely while operating close to the shore. Also, green laser light detection and ranging (lidar) acquisitions are expensive in remote locations. Previous research has demonstrated that spectral band ratio-based techniques, commonly called the natural logarithm approach, may lead to more precise measurements and modeling of bathymetry because of the phenomenon that different substrates at the same depth have approximately equal ratio values. The goal of this research was to apply the band ratio technique to Landsat 8 at-sensor radiance imagery and WorldView-3 atmospherically corrected imagery in the coastal waters surrounding the Majuro Atoll, Republic of the Marshall Islands, to derive near-shore bathymetry that could be incorporated into a seamless topobathymetric digital elevation model of Majuro. Attenuation of light within the water column was characterized by measuring at-sensor radiance and reflectance at different depths and calculating an attenuation coefficient. Bathymetric lidar data, collected by the U.S. Naval Oceanographic Office in 2006, were used to calibrate the SDB results. The bathymetric lidar yielded a strong linear relation with water depths. The Landsat 8-derived SDB estimates derived from the blue/green band ratio exhibited a water attenuation extinction depth of 6 meters with a coefficient of determination R2=0.9324. Estimates derived from the coastal/red band ratio had an R2=0.9597. At the same extinction depth, SDB estimates derived from WorldView-3 imagery exhibited an R2=0.9574. Because highly dynamic coastal shorelines can be affected by erosion, wetland loss, hurricanes, sea-level rise, urban development, and population growth, consistent bathymetric data are needed to better understand sensitive coastal land/water interfaces in areas subject to coastal disasters.

Climate-driven variations in thermal forcing across a nearshore reef system during a marine heat wave and its potential impact on coral calcification

NASA Astrophysics Data System (ADS)

Falter, J.; Zhang, Z.; Lowe, R.; Foster, T.; McCulloch, M. T.

2016-02-01

We examined the oceanic and atmospheric forces driving seasonal and spatial variability in water temperature across backreef and lagoonal habitats at Coral Bay at Ningaloo Reef, Western Australia before, during, and after a historically unprecedented marine heat wave and resulting mass bleaching event in 2010-2011. Local deviations in the mean daily temperature of nearshore reef waters from offshore values were a linear function of the combined effect of net atmospheric heating and offshore wave height and period . While intra-annual variation in local heat exchange was driven mainly by seasonal changes in short-wave radiation; intra-annual variation in local cooling was driven mostly by changes in relative humidity (r2 = 0.60) and wind speed (r2 = 0.31) which exhibited no apparent seasonality. We demonstrate good agreement between nearshore reef temperatures modeled from offshore sea surface temperatures (SST), offshore wave forcing, and local atmospheric heat fluxes with observed temperatures using a simple linear model (r2 = 0.31 to 0.69, root-mean-square error = 0.4°C to 0.9°C). Using these modeled nearshore reef temperature records, we show that during the heat wave local thermal stresses across the reef reached as high as 18-34 °C-weeks and were being both intensified and accelerated by regional climate forcing when compared with offshore waters (12.6 °C-weeks max). Measurements of coral calcification made in Coral Bay following the bleaching event appear to lack any distinct seasonality; possibly due to the long-term effects of acute thermal stress. However, similarly minimal seasonality in calcification rates had also been observed in an Acropora-dominated community at Ningaloo years before the heat wave as well as more recently in coral from regions in WA that had avoided mass bleaching. These observations, in conjunction with observations that most of the bleached communities within Coral Bay had recovered their color within 3-6 months of the bleaching event, suggest that how reef building coral respond to a severe thermal stress event can be somewhat nuanced depending on the local and regional setting.

Nearshore currents on the southern Namaqua shelf of the Benguela upwelling system

NASA Astrophysics Data System (ADS)

Fawcett, A. L.; Pitcher, G. C.; Shillington, F. A.

2008-05-01

Nearshore currents of the southern Namaqua shelf were investigated using data from a mooring situated three and a half kilometres offshore of Lambert's Bay, downstream of the Cape Columbine upwelling cell, on the west coast of South Africa. This area is susceptible to harmful algal blooms (HABs) and wind-forced variations in currents and water column structure are critical in determining the development, transport and dissipation of blooms. Time series of local wind data, and current and temperature profile data are described for three periods, considered to be representative of the latter part of the upwelling season (27 January-22 February), winter conditions (5-29 May) and the early part of the upwelling season (10 November-12 December) in 2005. Differences observed in mean wind strength and direction between data sets are indicative of seasonal changes in synoptic meteorological conditions. These quasi-seasonal variations in wind forcing affect nearshore current flow, leading to mean northward flow in surface waters early in the upwelling season when equatorward, upwelling-favourable winds are persistent. Mean near-surface currents are southward during the latter part of the upwelling season, consistent with more prolonged periods of relaxation from equatorward winds, and under winter conditions when winds were predominantly poleward. Within these seasonal variations in mean near-surface current direction, two scales of current variability were evident within all data sets: strong inertial oscillations were driven by diurnal winds and introduced vertical shear into the water column enhancing mixing across the thermocline, while sub-inertial current variability was driven by north-south wind reversals at periods of 2-5 days. Sub-inertial currents were found to lag wind reversals by approximately 12 h, with a tendency for near-surface currents to flow poleward in the absence of wind forcing. Consistent with similar sites along the Californian and Iberian coasts, the headland at Cape Columbine is considered to influence currents and circulation patterns during periods of relaxation from upwelling-favourable winds, favouring the development of a nearshore poleward current, leading to poleward advection of warm water, the development of stratification, and the creation of potentially favourable conditions for HAB development.

A Quick Response Forecasting Model of Pathogen Transport and Inactivation in Near-shore Regions

NASA Astrophysics Data System (ADS)

Liu, L.; Fu, X.

2011-12-01

Modeling methods supporting water quality assessments play a critical role by facilitating people to understand and promptly predict the potential threat of waterborne bacterial pathogens pose to human health. A mathematical model to describe and predict bacterial levels can provide foundation for water managers in making decisions on whether a water system is safe to open to the public. The inactivation (decay or die-off) rate of bacteria is critical in a bacterial model by controlling bacterial concentration in waters and depends on numerous factors of hydrodynamics, meteorology, geology, chemistry and biology. Transport and fate of waterborne pathogens in fresh water systems is an essentially three-dimensional problem, which requires a coupling of hydrodynamic equations and transport equations that describe the pathogen and suspended sediment dynamics. However, such an approach could be very demanding and time consuming from a practical point of view due to excess computational efforts. Long computation time may lead people unintentionally drinking or swimming in the contaminated water during the period before the predictive results of water quality come out. Therefore, it is very necessary to find a quick-response model to forecast bacterial concentration instantly to protect human health without any delay. Nearshore regions are the most commonly and directly used area for people in a huge water system. The prior multi-dimensional investigations of E. Coli and Enterococci inactivation in literature indicate that along-shore current predominated the nearshore region. Consequently, the complex dynamic conditions may be potentially simplified to one-dimensional scenario. In this research, a one-dimensional model system coupling both hydrodynamic and bacterial transport modules is constructed considering different complex processes to simulate the transport and fate of pathogens in nearshore regions. The quick-response model mainly focuses on promptly forecasting purpose and will be verified and calibrated with the available data collected from southern Lake Michigan. The modeling results will be compared with those from prior multi-dimensional models. This model is specifically effective for the outfall-controlled waters, where pathogens are primarily predominated by loadings from nearby tributaries and tend to show wide variations in concentrations.

Taxonomic and numerical sufficiency in a Lower and Middle Miocene molluscan metacommunity of the Central Paratethys

NASA Astrophysics Data System (ADS)

Zuschin, Martin; Nawrot, Rafal; Harzhauser, Mathias; Mandic, Oleg

2015-04-01

Among the most important questions in quantitative palaeoecology is how taxonomic and numerical resolution affect the analysis of community and metacommunity patterns. A species-abundance data set (10 localities, 213 bulk samples, 478 species, > 49,000 shells) from Burdigalian, Langhian and Serravallian benthic marine molluscan assemblages of the Central Paratethys was studied for this purpose. Assemblages are from two nearshore habitats (estuarine and marine intertidal) and three subtidal habitats (estuarine, fully marine sandy, and fully marine pelitic), which represent four biozones and four 3rd order depositional sequences over more than three million years, and are developed along the same depth-related environmental gradient. Double-standardized data subsampled to 19 samples per habitat, each with a minimum of 50 specimens, were used to calculate R²-values from PERMANOVA as a measure of differences between habitats at three taxonomic levels (species, genera and families) and at five levels of data transformation (raw abundances, percentages, square-root transformed percentages, fourth-root transformed percentages, presence-absence data). Species discriminate better between habitats than genera and families, but the differences between taxonomic levels are much stronger in the subtidal, where genera and families have more species than than in the intertidal. When all habitats are compared percentages and square-root transformed percentages discriminate equally well and perform better than higher levels of data transformation. Among nearshore and among subtidal habitats, however, the ability to discriminate between habitats increases with the level of data transformation (i.e., it is best for fourth-root transformed percentages and presence-absence data). The impact of decreasing taxonomic resolution is of minor importance in nearshore habitats, which are characterized by similar assemblages showing strong dominance of few widely distributed species, and many families represented by only one species (77.9%). Consequently, the differentiation between nearshore habitats is much weaker compared to subtidal assemblages. The latter are characterized by more distinct, relatively even assemblages with comparatively few families represented by only one species (64.2%) and many rare taxa, whose importance is emphasized by higher levels of data transformation.

Intertidal Sandbar Welding as a Primary Source of Sediment for Dune Growth: Evidence from a Large Scale Field Experiment

NASA Astrophysics Data System (ADS)

Cohn, N.; Ruggiero, P.; de Vries, S.

2016-12-01

Dunes provide the first line of defense from elevated water levels in low-lying coastal systems, limiting potentially major flooding, economic damages, and loss of livelihood. Despite the well documented importance of healthy dunes, our predictive ability of dune growth, particularly following erosive storm events, remains poor - resulting in part from traditionally studying the wet and dry beach as separate entities. In fact, however, dune recovery and growth is closely tied to the subtidal morphology and the nearshore hydrodynamic conditions, necessitating treating the entire coastal zone from the shoreface to the backshore as an integrated system. In this context, to further improve our understanding of the physical processes allowing for beach and dune growth during fair weather conditions, a large field experiment, the Sandbar-aEolian Dune EXchange EXperiment, was performed in summer 2016 in southwestern Washington, USA. Measurements of nearshore and atmospheric hydrodynamics, in-situ sediment transport, and morphology change provide insight into the time and space scales of nearshore-beach-dune exchanges along a rapidly prograding stretch of coast over a 6 week period. As part of this experiment, the hypothesis that dune growth is limited by the welding of intertidal sandbars to the shoreline (Houser, 2009) was tested. Using laser particle counters, bed elevation sensors (sonar altimeters and Microsoft Kinect), continuously logging sediment traps, RGB and IR cameras, and repeat morphology surveys (terrestrial lidar, kite based structure from motion, and RTK GPS), spatial and temporal trends in aeolian sediment transport were assessed in relation to the synoptic onshore migration and welding of intertidal sandbars. Observations from this experiment demonstrate that (1) the intertidal zone is the primary source of sediment to the dunes during non-storm conditions, (2) rates of saltation increase during later stages of bar welding but equivalent wind conditions, and (3) alongshore variability in rates of backshore fluxes appear to be related to alongshore variability in intertidal morphology. These observations quantitatively support the Houser (2009) bar welding hypothesis and provide valuable new insights on nearshore-beach-dune sediment exchanges

Primary Production and Respiration in the Louisiana Coastal Current Drive Patterns of Metabolism and Oxygen on the Louisiana Shelf

NASA Astrophysics Data System (ADS)

Lehrter, J. C.; Fung, M.

2017-12-01

Nutrients loads delivered by the Mississippi River to the Louisiana continental shelf (LCS) stimulate phytoplankton production of organic matter and coupled community respiration. These processes ultimately consume oxygen in bottom waters and promote the development of hypoxia and anoxia on the LCS. Several recent studies have emphasized the importance of nearshore (<15 m depth) phytoplankton production and respiration as a principal driver of heterotrophy and oxygen concentration patterns across this shelf. However, no studies to date have measured these nearshore rates. Other studies have invoked a more classical pattern of surface water primary production fueling water-column and bottom water respiration directly beneath through vertical deposition of organic matter. Yet, patterns of heterotrophy that have been observed across most of the LCS do not seem to support this hypothesis. In this study, we investigated these two different ideas by measuring primary production and respiration rates in distinct water masses at stations spanning salinity and depth gradients on the LCS in spring and summer of 2017. Over the course of this study, we have consistently observed highest primary production and respiration rates in nearshore waters of the Louisiana Coastal Current. This narrow band of low salinity water deriving from the Mississippi and Atchafalaya rivers exhibits maximum production rates exceeding 200 mmol C m-3 d-1 and maximum P/R > 10. Other water masses investigated, which included: surface water at offshore locations (> 15 m depth), sub-surface chlorophylla maxima, mid-water O2 minima and maxima, and bottom water, had average production and respiration rates that were 4-10 fold lower than in the nearshore zone and P/R < 1. These results and a scaling analysis demonstrate the potential for organic matter subsidies from the Louisiana Coastal Current to fuel respiration across the wider shelf and downcoast of the river inputs. Further, the results support recent physical and modeling analyses indicating that mid-water O2 minima and maxima observed on the LCS are primarily derived from lateral advection as opposed to developing in place as a result of excess primary production, sinking, and respiration.

Laboratory Assessment of Potential Impacts to Dungeness Crabs from Disposal of Dredged Material from the Columbia River

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

Vavrinec, John; Pearson, Walter H.; Kohn, Nancy P.

2007-05-07

Dredging of the Columbia River navigation channel has raised concerns about dredging-related impacts on Dungeness crabs (Cancer magister) in the estuary, mouth of the estuary, and nearshore ocean areas adjacent to the Columbia River. The Portland District, U.S. Army Corps of Engineers engaged the Marine Sciences Laboratory (MSL) of the U.S. Department of Energy’s Pacific Northwest National Laboratory to review the state of knowledge and conduct studies concerning impacts on Dungeness crabs resulting from disposal during the Columbia River Channel Improvement Project and annual maintenance dredging in the mouth of the Columbia River. The present study concerns potential effects onmore » Dungeness crabs from dredged material disposal specific to the mouth of the Columbia River.« less

Activities and preliminary results of nearshore benthic habitat mapping in southern California, 1998

USGS Publications Warehouse

Cochrane, Guy R.; Lafferty, Kevin D.

2000-01-01

The nearshore benthic habitat of the Santa Barbara coast and Channel Islands supports a diversity of marine life that are commercially, recreationally, and intrinsically valuable. Some of these resources are known to be endangered including a variety of rockfish and the White Abalone. State and National agencies have been mandated to preserve and enhance these resources and require detailed habitat characterization in order to do so. This project will characterize and map the benthic habitat in areas that have been selected because they have been set aside as National Sanctuaries or State Preserves, or are areas of ongoing or planned fish population studies. Various management strategies are being developed to protect marine resources in the Santa Barbara Channel Islands Region. One approach under investigation is to implement no-take marine reserves (Agardy, T., 1997; Bohnsack, 1998; Roberts, 1997). One small reserve presently exists on Anacapa Island and there is a growing momentum to add additional reserves to form a reserve network (Lafferty et al., 2000). Reserves may provide relatively pristine marine communities in a wild state for study and appreciation. In addition, they may buffer some species from over-fishing. A key feature of marine reserve design is to protect a representation of the existing habitats in a region (Roberts, 1997). Unfortunately, the distribution of habitats is not well known in this area since the underwater equivalent of soils and vegetation maps that are widely available for terrestrial systems do not yet exist. Managers need habitat maps to help determine the most appropriate boundaries for reserves in a network in order to meet various criteria and goals (such as habitat representation, reserve size, habitat heterogeneity, reserve spacing, inclusion of sensitive habitats, etc.). Another use for habitat mapping is to better understand the distribution of those habitats that are particularly important to fished species or sensitive species. Combining habitat mapping with ongoing studies of egg and larval fish counts by the National Marine Fisheries Service (Russell Vetter), rockfish population studies by the California Department of Fish and Game (Dave VenTresca), and white abalone (Kevin Lafferty and others, USGS) will extend the ability to predict the distribution of these species and identify areas with appropriate habitat that might be suitable for restoration. Additional uses for habitat mapping include managing visitor use, kelp distribution, and archeological resources.

Otolith analysis of pre-restoration habitat use by Chinook salmon in the delta-flats and nearshore regions of the Nisqually River Estuary

USGS Publications Warehouse

Lind-Null, Angie; Larsen, Kim

2010-01-01

The Nisqually Fall Chinook population is one of 27 salmon stocks in the Puget Sound (Washington) evolutionarily significant unit listed as threatened under the federal Endangered Species Act (ESA). Extensive restoration of the Nisqually River delta ecosystem is currently taking place to assist in recovery of the stock as juvenile Fall Chinook salmon are dependent on the estuary. A pre-restoration baseline that includes the characterization of life history strategies, estuary residence times, growth rates, and habitat use is needed to evaluate the potential response of hatchery and natural origin Chinook salmon to restoration efforts and to determine restoration success. Otolith analysis was selected as a tool to examine Chinook salmon life history, growth, and residence in the Nisqually River estuary. Previously funded work on samples collected in 2004 (marked and unmarked) and 2005 (unmarked only) partially established a juvenile baseline on growth rates and length of residence associated with various habitats (freshwater, forested riverine tidal, emergent forested transition, estuarine emergent marsh, delta-flats and nearshore). However, residence times and growth rates for the delta-flats (DF) and nearshore (NS) habitats have been minimally documented due to small sample sizes. The purpose of the current study is to incorporate otolith microstructural analysis using otoliths from fish collected within the DF and NS habitats during sampling years 2004-08 to increase sample size and further evaluate between-year variation in otolith microstructure. Our results from this analysis indicated the delta-flats check (DFCK) on unmarked and marked Chinook samples in 2005-08 varied slightly in appearance from that seen on samples previously analyzed only from 2004. A fry migrant life history was observed on otoliths of unmarked Chinook collected in 2005, 2007, and 2008. Generally, freshwater mean increment width of unmarked fish, on average, was smaller compared to marked Chinook followed by tidal delta and DF/NS portions respectively. On average, the complete tidal delta growth rate was higher for marked Chinook compared to unmarked Chinook. The DF/NS growth rate was highest for unmarked and marked Chinook during 2008 compared to all other sampling years. The average DF/NS growth rate on unmarked Chinook was consistently lower than marked Chinook during all years; however, sample sizes were small during some years. Unmarked Chinook, on average, spent longer in the tidal delta compared to marked Chinook. Our results from this report suggest that otolith microstructural analysis can be a valuable tool in establishing baseline information on the utilization of Nisqually River estuary habitats by juvenile Chinook salmon prior to the newly funded restoration efforts.

Basic Investigations for Remote Sensing of Coastal Areas.

DTIC Science & Technology

for the delineation and analysis of bottom features in coastal areas. The focus is on the development of remote sensing techniques for delineating and classifying bottom features in the nearshore zone.

Influence of dreissenid mussels on catchability of benthic fishes in bottom trawls

USGS Publications Warehouse

Kocovsky, Patrick M.; Stapanian, Martin A.

2011-01-01

Inferring trends in true abundance of fish populations from catch per unit effort data requires either the knowledge of capture probability or the assumption that it is constant, both of which are unlikely contingencies. We developed and validated an index of catchability (a proxy measure for capture probability) from a long-term data set describing nearshore waters of western Lake Erie, and we used the index to test the hypothesis that catchability of four abundant benthic species captured in bottom trawls changed after the invasion of dreissenid mussels. We estimated daytime and nighttime catchability for 1972–1990 (predreissenid period) and 1991–2009 (dreissenid period); we then tested for differences between nighttime and daytime catchability in the predreissenid and dreissenid periods and the nighttime–daytime differential in catchability during the dreissenid period. We also tested relationships between Secchi depth and the catchability index via linear regression. Catchability indices for white perch Morone americana, yellow perch Perca flavescens, and trout-perch Percopsis omiscomaycus did not differ between daytime and nighttime during the predreissenid period. After establishment of dreissenids, all three of these species had lower daytime catchability than nighttime catchability and had positive nighttime–daytime differentials, indicating a shift toward higher nighttime catchability relative to daytime catchability. Changes in catchability indices for freshwater drum Aplodinotus grunniens were opposite the changes observed for the other three species, possibly because the freshwater drum is the only species that actively feeds on dreissenids. Catchability indices were negatively related to water clarity (Secchi depth) for three of the species. Our results are consistent with the hypothesis that catchability of the four most common benthic fish species captured in bottom trawls within nearshore waters of western Lake Erie changed after the dreissenid invasion because of increased water clarity and increased visibility, which led to greater daytime trawl avoidance.

Publications - GMC 407 | Alaska Division of Geological & Geophysical

Science.gov Websites

locations, and archive inventory for 32 near-shore marine sediment Vibracore samples, West Dock Causeway , Drilling procedures, sample descriptions, boring logs, borehole locations, and archive inventory for 32

National Weather Service Marine Text Forecasts

Science.gov Websites

Offshore NAVTEX Bay and Coastal Surf Zone Recreational Marine Weather Statements Special Marine Warnings Marine Weather Messages Alaska Bay and Coastal Great Lakes Open Lake Great Lakes Nearshore Great Lakes

Seasonal to interannual morphodynamics along a high-energy dissipative littoral cell

USGS Publications Warehouse

Ruggiero, P.; Kaminsky, G.M.; Gelfenbaum, G.; Voigt, B.

2005-01-01

A beach morphology monitoring program was initiated during summer 1997 along the Columbia River littoral cell (CRLC) on the coasts of northwest Oregon and southwest Washington, USA. This field program documents the seasonal through interannual morphological variability of these high-energy dissipative beaches over a variety of spatial scales. Following the installation of a dense network of geodetic control monuments, a nested sampling scheme consisting of cross-shore topographic beach profiles, three-dimensional topographic beach surface maps, nearshore bathymetric surveys, and sediment size distribution analyses was initiated. Beach monitoring is being conducted with state-of-the-art real-time kinematic differential global positioning system survey methods that combine both high accuracy and speed of measurement. Sampling methods resolve variability in beach morphology at alongshore length scales of approximately 10 meters to approximately 100 kilometers and cross-shore length scales of approximately 1 meter to approximately 2 kilometers. During the winter of 1997/1998, coastal change in the US Pacific Northwest was greatly influenced by one of the strongest El Nin??o events on record. Steeper than typical southerly wave angles resulted in alongshore sediment transport gradients and shoreline reorientation on a regional scale. The La Nin??a of 1998/1999, dominated by cross-shore processes associated with the largest recorded wave year in the region, resulted in net beach erosion along much of the littoral cell. The monitoring program successfully documented the morphological response to these interannual forcing anomalies as well as the subsequent beach recovery associated with three consecutive moderate wave years. These morphological observations within the CRLC can be generalized to explain overall system patterns; however, distinct differences in large-scale coastal behavior (e.g., foredune ridge morphology, sandbar morphometrics, and nearshore beach slopes) are not readily explained or understood.

Trends in developed land cover adjacent to habitat for threatened salmon in Puget Sound, Washington, USA.

PubMed

Bartz, Krista K; Ford, Michael J; Beechie, Timothy J; Fresh, Kurt L; Pess, George R; Kennedy, Robert E; Rowse, Melinda L; Sheer, Mindi

2015-01-01

For widely distributed species at risk, such as Pacific salmon (Oncorhynchus spp.), habitat monitoring is both essential and challenging. Only recently have widespread monitoring programs been implemented for salmon habitat in the Pacific Northwest. Remote sensing data, such as Landsat images, are therefore a useful way to evaluate trends prior to the advent of species-specific habitat monitoring programs. We used annual (1986-2008) land cover maps created from Landsat images via automated algorithms (LandTrendr) to evaluate trends in developed (50-100% impervious) land cover in areas adjacent to five types of habitat utilized by Chinook salmon (O. tshawytscha) in the Puget Sound region of Washington State, U.S.A. For the region as a whole, we found significant increases in developed land cover adjacent to each of the habitat types evaluated (nearshore, estuary, mainstem channel, tributary channel, and floodplain), but the increases were small (<1% total increase from 1986 to 2008). For each habitat type, the increasing trend changed during the time series. In nearshore, mainstem, and floodplain areas, the rate of increase in developed land cover slowed in the latter portion of the time series, while the opposite occurred in estuary and tributary areas. Watersheds that were already highly developed in 1986 tended to have higher rates of development than initially less developed watersheds. Overall, our results suggest that developed land cover in areas adjacent to Puget Sound salmon habitat has increased only slightly since 1986 and that the rate of change has slowed near some key habitat types, although this has occurred within the context of a degraded baseline condition.

Trends in Developed Land Cover Adjacent to Habitat for Threatened Salmon in Puget Sound, Washington, U.S.A.

PubMed Central

Bartz, Krista K.; Ford, Michael J.; Beechie, Timothy J.; Fresh, Kurt L.; Pess, George R.; Kennedy, Robert E.; Rowse, Melinda L.; Sheer, Mindi

2015-01-01

For widely distributed species at risk, such as Pacific salmon (Oncorhynchus spp.), habitat monitoring is both essential and challenging. Only recently have widespread monitoring programs been implemented for salmon habitat in the Pacific Northwest. Remote sensing data, such as Landsat images, are therefore a useful way to evaluate trends prior to the advent of species-specific habitat monitoring programs. We used annual (1986-2008) land cover maps created from Landsat images via automated algorithms (LandTrendr) to evaluate trends in developed (50-100% impervious) land cover in areas adjacent to five types of habitat utilized by Chinook salmon (O. tshawytscha) in the Puget Sound region of Washington State, U.S.A. For the region as a whole, we found significant increases in developed land cover adjacent to each of the habitat types evaluated (nearshore, estuary, mainstem channel, tributary channel, and floodplain), but the increases were small (<1% total increase from 1986 to 2008). For each habitat type, the increasing trend changed during the time series. In nearshore, mainstem, and floodplain areas, the rate of increase in developed land cover slowed in the latter portion of the time series, while the opposite occurred in estuary and tributary areas. Watersheds that were already highly developed in 1986 tended to have higher rates of development than initially less developed watersheds. Overall, our results suggest that developed land cover in areas adjacent to Puget Sound salmon habitat has increased only slightly since 1986 and that the rate of change has slowed near some key habitat types, although this has occurred within the context of a degraded baseline condition. PMID:25923327

Reducing risks of maintenance dredging on freshwater mussels (Unionidae) in the Big Sunflower River, Mississippi.

PubMed

Miller, Andrew C; Payne, Barry S

2004-11-01

In response to proposed dredging in a 122-km reach of the Big Sunflower River, Mississippi, we studied freshwater mussels (family: Unionidae) using qualitative, semi-quantitative, and quantitative (0.25 m(2) total substratum removal) methods in 1987, 1993, 1994, 2001, 2002, and 2003. Our objectives were to identify important mussel resources, to devise methods for minimizing dredging risks, and to identify habitat improvement features. Approximately 60% of the fauna was located on two high-density shoals characterized by extreme dominance of the commercially valuable threeridge (Amblema plicata). Shallow nearshore and main channel areas comprised approximately 10 and 88% of the aquatic habitat in the project area; however, these areas were of less importance for mussels and supported densities of approximately 5 and 0.5 individuals/m(2), respectively. Throughout the project area the mussel fauna exhibited little or no evidence of recent recruitment, dominance of relatively few species (either A. plicata, or the bank climber Plectomerus dombeyanus), and low species diversity (H') and evenness. No federally listed endangered or threatened mussels were found, although the pyramid pigtoe (Pleurobema pyramidatum), a species listed as endangered in Mississippi, was collected in and upstream of the project area. Two other state-listed species, Plethobasus cyphyus (sheepnose) and Quadrula cylindrica (rabbitsfoot), were only found on gravelly shoals upriver of the project area. Maintenance plans were redesigned to minimize environmental damage; a hydraulic cutterhead dredge will be used in most of the mainstem to reduce risk to nearshore habitats. High-density assemblages on four shoals will not be dredged and 150 and 100 m buffer zones will be left immediately up and downriver. Enhancements for aquatic biota will be created with gravel substratum and wing dams.

Coastal upwelling seasonality and variability of temperature and chlorophyll in a small coastal embayment

NASA Astrophysics Data System (ADS)

Walter, Ryan K.; Armenta, Kevin J.; Shearer, Brandon; Robbins, Ian; Steinbeck, John

2018-02-01

While the seasonality of wind-driven coastal upwelling in eastern boundary upwelling systems has long been established, many studies describe two distinct seasons (upwelling and non-upwelling), a generalized framework that does not capture details relevant to marine ecosystems. In this contribution, we present a more detailed description of the annual cycle and upwelling seasonality for an understudied location along the central California coast. Using both the mean monthly upwelling favorable wind stress and the monthly standard deviation, we define the following seasons (contiguous months) and a transitional period (non-contiguous months): "Winter Storms" season (Dec-Jan-Feb), "Upwelling Transition" period (Mar and Jun), "Peak Upwelling" season (Apr-May), "Upwelling Relaxation" season (Jul-Aug-Sep), and "Winter Transition" season (Oct-Nov). In order to describe the oceanic response to this upwelling wind seasonality, we take advantage of nearly a decade of full water-column measurements of temperature and chlorophyll made using an automated profiling system at the end of the California Polytechnic State University Pier in San Luis Obispo Bay, a small ( 2 km wide near study site) and shallow ( 10 m average bay depth) coastal embayment. Variability and average-year patterns are described inside the bay during the various upwelling seasons. Moreover, the role of the local coastline orientation and topography on bay dynamics is also assessed using long-term measurements collected outside of the bay. The formation of a seasonally variable upwelling shadow system and potential nearshore retention zone is discussed. The observations presented provide a framework on which to study interannual changes to the average-year seasonal cycle, assess the contribution of higher-frequency features to nearshore variability, and better predict dynamically and ecologically important events.

Occurrence of Escherichia coli and enterococci in Cladophora (Chlorophyta) in nearshore water and beach sand of Lake Michigan

USGS Publications Warehouse

Whitman, Richard L.; Shively, Dawn A.; Pawlik, Heather; Nevers, Meredith; Byappanahalli, Muruleedhara N.

2003-01-01

Each summer, the nuisance green alga Cladophora (mostly Cladophora glomerata) amasses along Lake Michigan beaches, creating nearshore anoxia and unsightly, malodorous mats that can attract problem animals and detract from visitor enjoyment. Traditionally, elevated counts of Escherichia coli are presumed to indicate the presence of sewage, mostly derived from nearby point sources. The relationship between fecal indicator bacteria and Cladophora remains essentially unstudied. This investigation describes the local and regional density ofEscherichia coli and enterococci in Cladophora mats along beaches in the four states (Wisconsin, Illinois, Indiana, and Michigan) bordering Lake Michigan. Samples of Cladophora strands collected from 10 beaches (n = 41) were assayed for concentrations of E. coli and enterococci during the summer of 2002. Both E. coli and enterococci were ubiquitous (up to 97% occurrence), with overall log mean densities (± standard errors) of 5.3 (± 4.8) and 4.8 (± 4.5) per g (dry weight). E. coli and enterococci were strongly correlated in southern Lake Michigan beaches (P< 0.001, R2 = 0.73, n = 17) but not in northern beaches (P = 0.892, n = 16). BothE. coli and enterococci survived for over 6 months in sun-dried Cladophora mats stored at 4°C; the residual bacteria in the dried alga readily grew upon rehydration. These findings suggest that Cladophora amassing along the beaches of Lake Michigan may be an important environmental source of indicator bacteria and call into question the reliability of E. coli and enterococci as indicators of water quality for freshwater recreational beaches.

Nearshore bars and the break-point hypothesis

USGS Publications Warehouse

Sallenger, A.H.; Howd, P.A.

1989-01-01

The set of hypotheses calling for bar formation at the break point was tested with field data. During two different experiments, waves were measured across the surf zone coincident with the development of a nearshore bar. We use a criterion, based on the wave height to depth ratio, to determine the offshore limit of the inner surf zone. During the first experiment, the bar became better developed and migrated offshore while remaining well within the inner surf zone. During the second experiment, the surf zone was narrower and we cannot rule out the possibility of break point processes contributing to bar development. We conclude that bars are not necessarily coupled with the break point and can become better developed and migrate offshore while being in the inner surf zone landward from initial wave breaking in the outer surf zone. ?? 1989.

ON PREDICTING INFRAGRAVITY ENERGY IN THE SURF ZONE.

USGS Publications Warehouse

Sallenger,, Asbury H.; Holman, Robert A.; Edge, Billy L.

1985-01-01

Flow data were obtained in the surf zone across a barred profile during a storm. RMS cross-shore velocities due to waves in the intragravity band (wave periods greater than 20 s) had maxima in excess of 0. 5 m/s over the bar crest. For comparison to measured spectra, synthetic spectra of cross-shore flow were computed using measured nearshore profiles. The structure, in the infragravity band, of these synthetic spectra corresponded reasonably well with the structure of the measured spectra. Total variances of measured cross-shore flow within the infragravity band were nondimensionalized by dividing by total infragravity variances of synthetic spectra. These nondimensional variances were independent of distance offshore and increased with the square of the breaker height. Thus, cross-shore flow due to infragravity waves can be estimated with knowledge of the nearshore profile and incident wave conditions. Refs.

Nearshore morphology and late Quaternary geologic framework of the northern Monterey Bay Marine Sanctuary, California

USGS Publications Warehouse

Anima, R.J.; Eittreim, S.L.; Edwards, B.D.; Stevenson, A.J.

2002-01-01

A combination of side-scanning sonar and high-resolution seismic reflection data image seafloor bedrock exposures and erosional features across the nearshore shelf. Sediment-filled troughs incise the inner shelf rock exposures and tie directly to modern coastal streams. The resulting bedrock geometry can be related to its resistance to erosion. Comparison of the depth of the transgressive erosional surface to recently developed sea level curves suggests a period of slow sea level rise during the early stages of post-interglacial marine transgression. The slow rise of sea level suggests an erosional episode that limited the preservation of buried paleo-channels beyond 70 m water depth. Seafloor features suggest that localized faulting in the area may have influenced the morphology of bedrock exposures and the coastline. ?? 2002 Elsevier Science B.V. All rights reserved.

Optimizing spectral wave estimates with adjoint-based sensitivity maps

NASA Astrophysics Data System (ADS)

Orzech, Mark; Veeramony, Jay; Flampouris, Stylianos

2014-04-01

A discrete numerical adjoint has recently been developed for the stochastic wave model SWAN. In the present study, this adjoint code is used to construct spectral sensitivity maps for two nearshore domains. The maps display the correlations of spectral energy levels throughout the domain with the observed energy levels at a selected location or region of interest (LOI/ROI), providing a full spectrum of values at all locations in the domain. We investigate the effectiveness of sensitivity maps based on significant wave height ( H s ) in determining alternate offshore instrument deployment sites when a chosen nearshore location or region is inaccessible. Wave and bathymetry datasets are employed from one shallower, small-scale domain (Duck, NC) and one deeper, larger-scale domain (San Diego, CA). The effects of seasonal changes in wave climate, errors in bathymetry, and multiple assimilation points on sensitivity map shapes and model performance are investigated. Model accuracy is evaluated by comparing spectral statistics as well as with an RMS skill score, which estimates a mean model-data error across all spectral bins. Results indicate that data assimilation from identified high-sensitivity alternate locations consistently improves model performance at nearshore LOIs, while assimilation from low-sensitivity locations results in lesser or no improvement. Use of sub-sampled or alongshore-averaged bathymetry has a domain-specific effect on model performance when assimilating from a high-sensitivity alternate location. When multiple alternate assimilation locations are used from areas of lower sensitivity, model performance may be worse than with a single, high-sensitivity assimilation point.

Using Integrated Ecosystem Observations from Gulf Watch Alaska to Assess the Effects of the 2014/2015 Pacific Warm Anomaly in the Northern Gulf of Alaska

NASA Astrophysics Data System (ADS)

Holderied, K.; Neher, T. H.; McCammon, M.; Hoffman, K.; Hopcroft, R. R.; Lindeberg, M.; Ballachey, B.; Coletti, H.; Esler, D.; Weingartner, T.

2016-02-01

The response of nearshore and coastal pelagic ecosystems in the northern Gulf of Alaska to the 2014-2015 Pacific Ocean warm anomaly is being assessed with multi-disciplinary observations of the Gulf Watch Alaska long-term ecosystem monitoring program. Gulf Watch Alaska is an integrated, multi-agency program, funded by the Exxon Valdez oil spill Trustee Council to track populations of nearshore and pelagic species injured by the 1989 oil spill, as well as the marine conditions that affect those species. While the primary program goals are to support management and sustained recovery of species injured directly and indirectly by the spill, the integration of oceanographic observations with monitoring of nearshore and pelagic food webs also facilitates detection and assessment of ecosystem changes. The initial 5-year phase of the Gulf Watch Alaska program was started in 2012 and has provided marine ecosystem observations through the transition in late 2013 from anomalously cool to anomalously warm ocean conditions in the Gulf of Alaska. We review results from and linkages between oceanographic, whale, seabird, intertidal, and plankton monitoring projects in Prince William Sound, Cook Inlet and the northern Gulf of Alaska shelf. We also assess the different ecosystem responses observed between the summers of 2014 and 2015, with the region experiencing unusual amounts of seabird and marine mammal mortalities and harmful algal bloom events in 2015.

Structure and Dynamics of the Shark Assemblage off Recife, Northeastern Brazil

PubMed Central

Afonso, André S.; Andrade, Humber A.; Hazin, Fábio H. V.

2014-01-01

Understanding the ecological factors that regulate elasmobranch abundance in nearshore waters is essential to effectively manage coastal ecosystems and promote conservation. However, little is known about elasmobranch populations in the western South Atlantic Ocean. An 8-year, standardized longline and drumline survey conducted in nearshore waters off Recife, northeastern Brazil, allowed us to describe the shark assemblage and to monitor abundance dynamics using zero-inflated generalized additive models. This region is mostly used by several carcharhinids and one ginglymostomid, but sphyrnids are also present. Blacknose sharks, Carcharhinus acronotus, were mostly mature individuals and declined in abundance throughout the survey, contrasting with nurse sharks, Ginglymostoma cirratum, which proliferated possibly due to this species being prohibited from all harvest since 2004 in this region. Tiger sharks, Galeocerdo cuvier, were mostly juveniles smaller than 200 cm and seem to use nearshore waters off Recife between January and September. No long-term trend in tiger shark abundance was discernible. Spatial distribution was similar in true coastal species (i.e. blacknose and nurse sharks) whereas tiger sharks were most abundant at the middle continental shelf. The sea surface temperature, tidal amplitude, wind direction, water turbidity, and pluviosity were all selected to predict shark abundance off Recife. Interspecific variability in abundance dynamics across spatiotemporal and environmental gradients suggest that the ecological processes regulating shark abundance are generally independent between species, which could add complexity to multi-species fisheries management frameworks. Yet, further research is warranted to ascertain trends at population levels in the South Atlantic Ocean. PMID:25010514

Structure and dynamics of the shark assemblage off Recife, Northeastern Brazil.

PubMed

Afonso, André S; Andrade, Humber A; Hazin, Fábio H V

2014-01-01

Understanding the ecological factors that regulate elasmobranch abundance in nearshore waters is essential to effectively manage coastal ecosystems and promote conservation. However, little is known about elasmobranch populations in the western South Atlantic Ocean. An 8-year, standardized longline and drumline survey conducted in nearshore waters off Recife, northeastern Brazil, allowed us to describe the shark assemblage and to monitor abundance dynamics using zero-inflated generalized additive models. This region is mostly used by several carcharhinids and one ginglymostomid, but sphyrnids are also present. Blacknose sharks, Carcharhinus acronotus, were mostly mature individuals and declined in abundance throughout the survey, contrasting with nurse sharks, Ginglymostoma cirratum, which proliferated possibly due to this species being prohibited from all harvest since 2004 in this region. Tiger sharks, Galeocerdo cuvier, were mostly juveniles smaller than 200 cm and seem to use nearshore waters off Recife between January and September. No long-term trend in tiger shark abundance was discernible. Spatial distribution was similar in true coastal species (i.e. blacknose and nurse sharks) whereas tiger sharks were most abundant at the middle continental shelf. The sea surface temperature, tidal amplitude, wind direction, water turbidity, and pluviosity were all selected to predict shark abundance off Recife. Interspecific variability in abundance dynamics across spatiotemporal and environmental gradients suggest that the ecological processes regulating shark abundance are generally independent between species, which could add complexity to multi-species fisheries management frameworks. Yet, further research is warranted to ascertain trends at population levels in the South Atlantic Ocean.

Spatial and seasonal patterns of ichthyoplankton assemblages in the Haizhou Bay and its adjacent waters of China

NASA Astrophysics Data System (ADS)

Li, Zengguang; Ye, Zhenjiang; Wan, Rong

2015-12-01

Surveys were conducted in five voyages in Haizhou Bay and its adjacent coastal area from March to December 2011 during full moon spring tides. The ichthyoplankton assemblages and the environmental factors that affect their spatial and seasonal patterns were determined. Totally 35 and 12 fish egg and larvae taxa were identified, respectively. Over the past several decades, the egg and larval species composition has significantly changed in Haizhou Bay and its adjacent waters, most likely corresponding with the alteration of fishery resources, which are strongly affected by anthropogenic activities and climate change. The Bray-Curtis dissimilarity index identified four assemblages: near-shore bay assemblage, middle bay assemblage and two closely related assemblages (near-shore/middle bay assemblage and middle/edge of bay assemblage). The primary species of each assemblage principally reflected the spawning strategies of adult fish. The near-shore bay assemblage generally occurred in near-shore bay, with depths measuring <20 m, and the middle bay assemblage generally occurred in the middle of bay, with depths measuring 20 to 40 m. Spatial and seasonal variations in ichthyoplankton in each assemblage were determined by interactions between biological behavioral traits and oceanographic features, particularly the variation of local conditions within the constraint of a general reproductive strategy. The results of Spearman's rank correlation analysis indicated that both fish egg and larval abundance were positively correlated with depth, which is critical to the oceanographic features in Haizhou Bay.

The influence of a rocky reef and giant kelp on the cross-shelf propagation of nearshore internal bores

NASA Astrophysics Data System (ADS)

Rainville, E. J.; Walter, R. K.; Leary, P.; Woodson, C. B.; Monismith, S. G.; Nickols, K. J.

2017-12-01

Kelp forests are one of the most vibrant and productive ecosystems in the California coastal ocean and the health of these ecosystems is heavily influenced by the local hydrodynamics. In southern Monterey Bay, the nearshore environment is characterized by large areas of rocky reef and giant kelp (Macrocystis pyrifera) forests. The physical environment at this location is dominated by nearshore internal bores, which produce transient stratification and mixing events associated with the delivery of subthermocline waters to shallow regions. During the spring of 2013, a large array of oceanographic moorings measuring temperature and velocity at an extremely high spatiotemporal resolution was deployed to investigate the role of rocky reefs and giant kelp forests on the cross-shelf propagation of shoaling internal waves and bores. We take advantage of a unique site location where a rocky reef with giant kelp was located adjacent to a large sandy channel to compare temperature dynamics and flow both inside and outside the kelp forest. Preliminary analysis suggests that the rocky reef and kelp forest act to limit the cross-shelf extent of the internal bore features and dampen temperature variance at higher frequencies when compared to the adjacent sand channel. Moreover, by defining an internal bore strength index, we will explore temperature and velocity dynamics with and without internal bore forcing along the two cross-shelf transects (i.e., rocky reef and sandy channel transects).

Prey selection by the Lake Superior fish community

USGS Publications Warehouse

Isaac, Edmund J.; Hrabik, Thomas R.; Stockwell, Jason D.; Gamble, Allison E.

2012-01-01

Mysis diluviana is an important prey item to the Lake Superior fish community as found through a recent diet study. We further evaluated this by relating the quantity of prey found in fish diets to the quantity of prey available to fish, providing insight into feeding behavior and prey preferences. We describe the seasonal prey selection of major fish species collected across 18 stations in Lake Superior in spring, summer, and fall of 2005. Of the major nearshore fish species, bloater (Coregonus hoyi), rainbow smelt (Osmerus mordax), and lake whitefish (Coregonus clupeaformis) consumed Mysis, and strongly selected Mysis over other prey items each season. However, lake whitefish also selected Bythotrephes in the fall when Bythotrephes were numerous. Cisco (Coregonus artedi), a major nearshore and offshore species, fed largely on calanoid copepods, and selected calanoid copepods (spring) and Bythotrephes (summer and fall). Cisco also targeted prey similarly across bathymetric depths. Other major offshore fish species such as kiyi (Coregonus kiyi) and deepwater sculpin (Myoxocephalus thompsoni) fed largely on Mysis, with kiyi targeting Mysis exclusively while deepwater sculpin did not prefer any single prey organism. The major offshore predator siscowet lake trout (Salvelinus namaycush siscowet) consumed deepwater sculpin and coregonines, but selected deepwater sculpin and Mysis each season, with juveniles having a higher selection for Mysis than adults. Our results suggest that Mysis is not only a commonly consumed prey item, but a highly preferred prey item for pelagic, benthic, and piscivorous fishes in nearshore and offshore waters of Lake Superior.

Moderate-resolution sea surface temperature data for the nearshore North Pacific

USGS Publications Warehouse

Payne, Meredith C.; Reusser, Deborah A.; Lee, Henry; Brown, Cheryl A.

2011-01-01

Coastal sea surface temperature (SST) is an important environmental characteristic in determining the suitability of habitat for nearshore marine and estuarine organisms. This publication describes and provides access to an easy-to-use coastal SST dataset for ecologists, biogeographers, oceanographers, and other scientists conducting research on nearshore marine habitats or processes. The data cover the Temperate Northern Pacific Ocean as defined by the 'Marine Ecosystems of the World' (MEOW) biogeographic schema developed by The Nature Conservancy. The spatial resolution of the SST data is 4-km grid cells within 20 km of the shore. The data span a 29-year period - from September 1981 to December 2009. These SST data were derived from Advanced Very High Resolution Radiometer (AVHRR) instrument measurements compiled into monthly means as part of the Pathfinder versions 5.0 and 5.1 (PFSST V50 and V51) Project. The processing methods used to transform the data from their native Hierarchical Data Format Scientific Data Set (HDF SDS) to georeferenced, spatial datasets capable of being read into geographic information systems (GIS) software are explained. In addition, links are provided to examples of scripts involved in the data processing steps. The scripts were written in the Python programming language, which is supported by ESRI's ArcGIS version 9 or later. The processed data files are also provided in text (.csv) and Access 2003 Database (.mdb) formats. All data except the raster files include attributes identifying realm, province, and ecoregion as defined by the MEOW classification schema.

Status and trends in the fish community of Lake Superior, 2012

USGS Publications Warehouse

Gorman, Owen T.; Evrard, Lori M.; Cholwek, Gary A.; Vinson, Mark

2012-01-01

Due to ship mechanical failures, nearshore sampling was delayed from mid-May to mid-June to mid-June to late August. The shift to summer sampling when the lake was stratified may have affected our estimates, thus our estimates of status and trends for the nearshore fish community in 2012 are tentative, pending results of future surveys. However, the results of the 2012 survey are comparable with those during 2009 and 2010 when lake-wide fish biomass declined to < 1.40 kg/ha. Declines in prey fish biomass since the late 1990s can be attributed to a combination of increased predation by recovered lake trout populations and infrequent and weak recruitment by the principal prey fishes, cisco and bloater. In turn declines in lake trout biomass since the mid-2000s are likely linked to declines in prey fish biomass. If lean and siscowet lake trout populations in nearshore waters continue to remain at current levels, predation mortality will likely maintain the relatively low prey fish biomass observed in recent years. Alternatively, if lake trout populations show a substantial decline in abundance in upcoming years, prey fish populations may rebound in a fashion reminiscent to what occurred in the late 1970s to mid-1980s. However, this scenario depends on substantial increases in harvest of lake trout, which seems unlikely given that levels of lake trout harvest have been flat or declining in many regions of Lake Superior since 2000.

Effects of episodic rainfall on a subterranean estuary

NASA Astrophysics Data System (ADS)

Yu, Xiayang; Xin, Pei; Lu, Chunhui; Robinson, Clare; Li, Ling; Barry, D. A.

2017-07-01

Numerical simulations were conducted to examine the effect of episodic rainfall on nearshore groundwater dynamics in a tidally influenced unconfined coastal aquifer, with a focus on both long-term (yearly) and short-term (daily) behavior of submarine groundwater discharge (SGD) and seawater intrusion (SWI). The results showed nonlinear interactions among the processes driven by rainfall, tides, and density gradients. Rainfall-induced infiltration increased the yearly averaged fresh groundwater discharge to the ocean but reduced the extents of the saltwater wedge and upper saline plume as well as the total rate of seawater circulation through both zones. Overall, the net effect of the interactions led to an increase of the SGD. The nearshore groundwater responded to individual rainfall events in a delayed and cumulative fashion, as evident in the variations of daily averaged SGD and salt stored in the saltwater wedge (quantifying the extent of SWI). A generalized linear model (GLM) along with a Gamma distribution function was developed to describe the delayed and prolonged effect of rainfall events on short-term groundwater behavior. This model validated with results of daily averaged SGD and SWI from the simulations of groundwater and solute transport using independent rainfall data sets, performed well in predicting the behavior of the nearshore groundwater system under the combined influence of episodic rainfall, tides, and density gradients. The findings and developed GLM form a basis for evaluating and predicting SGD, SWI, and associated mass fluxes from unconfined coastal aquifers under natural conditions, including episodic rainfall.

Humpback Dolphins (Genus Sousa) in India: An Overview of Status and Conservation Issues.

PubMed

Sutaria, Dipani; Panicker, Divya; Jog, Ketki; Sule, Mihir; Muralidharan, Rahul; Bopardikar, Isha

2015-01-01

This chapter aims to collate recent work done by different research teams along the Indian coast and presents research plans for the conservation and management of the genus Sousa in Indian waters. Humpback dolphins are the most common nearshore cetaceans found along the Indian coast. The taxonomy is confused, but two or more species of humpback dolphins may be present in India. Dedicated research on humpback dolphins and other cetaceans has been initiated only in the past few years and vast gaps in the ecology and conservation of the genus from the region remain. Dedicated and opportunistic research indicates that humpback dolphin presence is continuous along the west coast of India, owing to the contiguous favourable habitat of shallow nearshore waters, while along the east coast humpback dolphins are apparently found in pockets. Humpback dolphins are also the most numerous in incidental catch records from the coast, owing to the large overlap in space use with nearshore fisheries like small gillnets, trawls, shore seines and purse seines. Along many coastal sites, humpback dolphins are known to cause damage and depredation of fish catch of certain fishing gears, making them unpopular. At the same time, many fishers along the west coast have developed local dolphin-watching programmes as an alternate source of livelihood, providing positive impetus for conservation. However, research on the long-term effects of dolphin watching and its management is required. Some recommendations for more effective management of this species are made. © 2015 Elsevier Ltd All rights reserved.

Cross-shore variation of wind-driven flows on the inner shelf in Long Bay, South Carolina, United States

NASA Astrophysics Data System (ADS)

Gutierrez, Benjamin T.; Voulgaris, George; Work, Paul A.

2006-03-01

The cross-shore structure of subtidal flows on the inner shelf (7 to 12 m water depth) of Long Bay, South Carolina, a concave-shaped bay, is examined through the analysis of nearly 80 days of near-bed (1.7-2.2 m above bottom) current observations acquired during the spring and fall of 2001. In the spring and under northeastward winds (upwelling favorable) a two-layered flow was observed at depths greater than 10 m, while closer to the shore the currents were aligned with the wind. The two-layered flow is attributed to the presence of stratification, which has been observed under similar conditions in the South Atlantic Bight. When the wind stress was southwestward (downwelling favorable) and exceeded 0.1 N/m2, vertical mixing occurred, the two-layered flow pattern disappeared, and currents were directed alongshore with the wind at all sites and throughout the water column. In the fall, near-bed flows close to the shore (water depth <7 m) were often reduced compared to or opposed those measured farther offshore under southwestward winds. A simplified analysis of the depth-averaged, alongshore momentum balance illustrates that the alongshore pressure gradient approached or exceeded the magnitude of the alongshore wind stress at the same time that the nearshore alongshore current opposed the wind stress and alongshore currents farther offshore. In addition, the analysis suggests that the wind stress is reduced closer to shore so that the alongshore pressure gradient is large enough to drive the flow against the wind.

Mesozoic (Upper Jurassic-Lower Cretaceous) deep gas reservoir play, central and eastern Gulf coastal plain

USGS Publications Warehouse

Mancini, E.A.; Li, P.; Goddard, D.A.; Ramirez, V.O.; Talukdar, S.C.

2008-01-01

The Mesozoic (Upper Jurassic-Lower Cretaceous) deeply buried gas reservoir play in the central and eastern Gulf coastal plain of the United States has high potential for significant gas resources. Sequence-stratigraphic study, petroleum system analysis, and resource assessment were used to characterize this developing play and to identify areas in the North Louisiana and Mississippi Interior salt basins with potential for deeply buried gas reservoirs. These reservoir facies accumulated in Upper Jurassic to Lower Cretaceous Norphlet, Haynesville, Cotton Valley, and Hosston continental, coastal, and marine siliciclastic environments and Smackover and Sligo nearshore marine shelf, ramp, and reef carbonate environments. These Mesozoic strata are associated with transgressive and regressive systems tracts. In the North Louisiana salt basin, the estimate of secondary, nonassociated thermogenic gas generated from thermal cracking of oil to gas in the Upper Jurassic Smackover source rocks from depths below 3658 m (12,000 ft) is 4800 tcf of gas as determined using software applications. Assuming a gas expulsion, migration, and trapping efficiency of 2-3%, 96-144 tcf of gas is potentially available in this basin. With some 29 tcf of gas being produced from the North Louisiana salt basin, 67-115 tcf of in-place gas remains. Assuming a gas recovery factor of 65%, 44-75 tcf of gas is potentially recoverable. The expelled thermogenic gas migrated laterally and vertically from the southern part of this basin to the updip northern part into shallower reservoirs to depths of up to 610 m (2000 ft). Copyright ?? 2008. The American Association of Petroleum Geologists. All rights reserved.

Monitoring land use/cover changes on the Romanian Black Sea Coast

NASA Astrophysics Data System (ADS)

Zoran, L. F. V.; Dida, A. I.; Zoran, M. A.

2014-10-01

Remotely sensed satellite data are critical to understanding the coastal zones' physical and social systems interaction, complementing ground based methods and providing accurate wide range, objective and comparable, at widely-varying scales, synoptically data. For some environmental agreements remote sensing may provide the only viable means of compliance verification because the phenomena are monitored occurs over large and inaccessible geographic areas. The main aim of this paper was the assessment of coastal zone land cover/use changes based on fusion technique of satellite remote sensing imagery. The evaluation of coastal zone landscapes was based upon different sub-functions which refer to landscape features such as water, soil, land-use, buildings, groundwater, biotope types. A newly proposed sub-pixel mapping algorithm was applied to a set of multispectral and multitemporal satellite data for Danube Delta, Constantza and Black Sea coastal zone areas in Romania. A land cover classification and subsequent environmental quality analysis for change detection was done based on Landsat TM , Landsat ETM, QuickBird satellite images over 1990 to 2013 period of time. Spectral signatures of different terrain features have been used to separate and classify surface units of coastal zone and sub-coastal zone area.The change in the position of the coastline in Constantza area was examined in relation with the urban expansion. A distinction was made between landfill/sedimentation processes on the one hand and dredging/erosion processes on the other. We considered the Romanian Black Sea coastal zone dynamics in connection with the spatio-temporal variation of physical and biogeochemical processes and their influences on the environmental state in the near-shore area.

Longshore water-current velocity and the potential for transport of contaminants—A pilot study in Lake Erie from Walnut Creek to Presque Isle State Park beaches, Erie, Pennsylvania, June and August 2015

USGS Publications Warehouse

Hittle, Elizabeth A.

2017-04-20

Bacteria-driven restrictions and (or) advisories on swimming at beaches in Presque Isle State Park (PISP), Erie, Pennsylvania, can occur during the summer months. One of the suspected sources of bacteria is sediment. A terrestrial sediment source to the west of PISP is Walnut Creek, which discharges to Lake Erie about 8.5 kilometers southwest of PISP Beach 1. On June 24, June 25, August 18, and August 19, 2015, synoptic surveys were conducted by the U.S. Geological Survey, in cooperation with the Pennsylvania Sea Grant, in Lake Erie between Walnut Creek and PISP Beach 1 to characterize the water-current velocity and direction to determine whether sediment from Walnut Creek could be affecting the PISP beaches. Water-quality data (temperature, specific conductance, and turbidity) were collected in conjunction with the synoptic surveys in June. Water-quality data (Escherichia coli [E. coli] bacteria, temperature, and turbidity) were collected about a meter from the shore (nearshore) on June 24, August 19, and after a precipitation event on August 11, 2015. Additionally, suspended sediment was collected nearshore on June 24 and August 11, 2015. Samples collected near Walnut Creek during all three bacterial sampling events contained higher counts than other samples. Counts steadily decreased from west to east, then increased about 1–2 kilometers from PISP Beach 1; however, this study was not focused on examining other potential sources of bacteria.The Velocity Mapping Toolbox (VMT) was used to process the water-current synoptic surveys, and the results were visualized within ArcMap. For the survey accomplished on June 24, 2015, potential paths a particle could take between Walnut Creek and PSIP Beach 1 if conditions remained steady over a number of hours were visualized. However, the water-current velocity and direction were variable from one day to the other, indicating this was likely an unrealistic assumption for the study area. This analysis was not accomplished for the other surveys due to unsteady lake conditions encountered on June 25 and August 18, and reduced quality of the survey on August 19.

Early Restoration Public Meeting, Washington, DC | NOAA Gulf Spill

Science.gov Websites

benefit injured marshes, coastal dune and nearshore habitats, oysters, and human uses (on water recreation . Department of Commerce Herbert Hoover Building Auditorium 1401 Constitution Ave., NW Washington, D.C. 20230

An Archaean oxygen oasis

NASA Astrophysics Data System (ADS)

Gomes, Maya L.

2018-02-01

The first of two stepwise increases in atmospheric oxygen occurred at the end of the Archaean eon. Analyses of sulfur and iron isotopes in pyrite reveal a near-shore environment that hosted locally oxygenated conditions in the Mesoarchaean era.

Bodega Ocean Observing Node (BOON).

NASA Astrophysics Data System (ADS)

Largier, J. L.; Chow, V. I.; Williams, S. L.; Botsford, L. W.; Morgan, S. G.; Nyden, B.; Tustin, J. A.; McAfee, S.; Shideler, D.

2004-12-01

The Bodega Ocean Observing Node (BOON) is comprised of radar mapping of surface currents, a moored current profiler, and shoreline oceanographic and meteorological observations. Ongoing shoreline data on temperature and salinity date back to 1955, with continuous records of sealevel, wind, meteorology, and chlorophyll fluorescence starting more recently. Radar observations started in 2001 with deployment of two CODAR antennae. Together with a third CODAR unit deployed in 2002, these provide coverage from Pt Reyes north to the CODE line. Real-time ADCP data from the mooring started in late 2004. Plans include nearshore wave data, CTD/fluorescence data from the mooring, and deployment of a nutrient sensor at the shoreline. This coastal ocean observing node is part of the state-funded COCMP-NC program and the CeNCOOS regional association for central and northern California. Ancillary regional data are available on offshore winds (NDBC buoys), offshore waves (CDIP buoy), river flow, and satellite observations. The value of this suite of measurements is built on (1) detailed understanding of circulation, derived from WEST, CODE, and other prior studies of this region, including mesoscale atmosphere and ocean modeling, (2) active integration of circulation patterns in ongoing studies of planktonic and benthic ecology, and (3) direct interaction with local, state and federal agencies with interest in this region. To-date, the ongoing data series have shown potential for improved understanding and monitoring of fishery populations such as salmon and crab, as well as water quality concerns including oil spills and toxic pollutants. Through an active involvement in local studies and environmental management issues, BOON seeks to develop alternatives to supply-side thinking in the design of coastal ocean observing systems. BOON is based at the Bodega Marine Laboratory and thus provides invaluable support for academic study of more fundamental questions, such as carbon budgets in coastal upwelling systems and the importance of the spatial structure of coastal pelagic habitat.

Coral records of reef-water pH across the central Great Barrier Reef, Australia: assessing the influence of river runoff on inshore reefs

NASA Astrophysics Data System (ADS)

D'Olivo, J. P.; McCulloch, M. T.; Eggins, S. M.; Trotter, J.

2015-02-01

The boron isotopic (δ11Bcarb) compositions of long-lived Porites coral are used to reconstruct reef-water pH across the central Great Barrier Reef (GBR) and assess the impact of river runoff on inshore reefs. For the period from 1940 to 2009, corals from both inner- and mid-shelf sites exhibit the same overall decrease in δ11Bcarb of 0.086 ± 0.033‰ per decade, equivalent to a decline in seawater pH (pHsw) of ~0.017 ± 0.007 pH units per decade. This decline is consistent with the long-term effects of ocean acidification based on estimates of CO2 uptake by surface waters due to rising atmospheric levels. We also find that, compared to the mid-shelf corals, the δ11Bcarb compositions of inner-shelf corals subject to river discharge events have higher and more variable values, and hence higher inferred pHsw values. These higher δ11Bcarb values of inner-shelf corals are particularly evident during wet years, despite river waters having lower pH. The main effect of river discharge on reef-water carbonate chemistry thus appears to be from reduced aragonite saturation state and higher nutrients driving increased phytoplankton productivity, resulting in the drawdown of pCO2 and increase in pHsw. Increased primary production therefore has the potential to counter the more transient effects of low-pH river water (pHrw) discharged into near-shore environments. Importantly, however, inshore reefs also show a consistent pattern of sharply declining coral growth that coincides with periods of high river discharge. This occurs despite these reefs having higher pHsw, demonstrating the overriding importance of local reef-water quality and reduced aragonite saturation state on coral reef health.

Identification and evaluation of shark bycatch in Georgia’s commercial shrimp trawl fishery with implications for management

USGS Publications Warehouse

Belcher, C.N.; Jennings, Cecil A.

2011-01-01

Many US states have recreational and commercial fisheries that occur in nursery areas occupied by subadult sharks and can potentially affect their survival. Georgia is one of few US states without a directed commercial shark fishery, but the state has a large, nearshore penaeid shrimp trawl fishery in which small sharks occur as bycatch. During our 1995-1998 investigation of bycatch in fishery-dependent sampling events, 34% of 127 trawls contained sharks. This bycatch totalled 217 individuals from six species, with Atlantic sharpnose shark, Rhizoprionodon terraenovae (Richardson), the most common and finetooth shark, Carcharhinus isodon (Müller & Henle) and spinner shark, Carcharhinus brevipinna (Müller & Henle), the least common. The highest catch rates for sharks occurred during June and July and coincided with the peak months of the pupping season for many species. Trawl tow speed and tow time did not significantly influence catch rates for shark species. Gear configurations [net type, turtle excluder device (TED), bycatch reduction device] affected catch rates for shark species. Results of this study indicate gear restrictions, a delayed season opening, or reduced bar spacing on TEDs may reduce shark bycatch in this fishery.

Identification and evaluation of shark bycatch in Georgia's commercial shrimp trawl fishery with implications for management

USGS Publications Warehouse

Belcher, C.N.; Jennings, C.A.

2011-01-01

Many US states have recreational and commercial fisheries that occur in nursery areas occupied by subadult sharks and can potentially affect their survival. Georgia is one of few US states without a directed commercial shark fishery, but the state has a large, nearshore penaeid shrimp trawl fishery in which small sharks occur as bycatch. During our 1995–1998 investigation of bycatch in fishery-dependent sampling events, 34% of 127 trawls contained sharks. This bycatch totalled 217 individuals from six species, with Atlantic sharpnose shark, Rhizoprionodon terraenovae (Richardson), the most common and finetooth shark, Carcharhinus isodon (Müller & Henle) and spinner shark, Carcharhinus brevipinna (Müller & Henle), the least common. The highest catch rates for sharks occurred during June and July and coincided with the peak months of the pupping season for many species. Trawl tow speed and tow time did not significantly influence catch rates for shark species. Gear configurations [net type, turtle excluder device (TED), bycatch reduction device] affected catch rates for shark species. Results of this study indicate gear restrictions, a delayed season opening, or reduced bar spacing on TEDs may reduce shark bycatch in this fishery.

Baseline and Projected Future Carbon Stocks and Fluxes in the Hawaiian Islands

NASA Astrophysics Data System (ADS)

Selmants, P. C.; Sleeter, B. M.; Giardina, C. P.; Zhu, Z.; Asner, G. P.

2016-12-01

Hawaii is characterized by steep climatic gradients and heterogeneous land cover within a small geographic area, presenting a model tropical system to capture ecosystem carbon dynamics across a wide range of climate, soil, and land use conditions. However, ecosystem carbon balance is poorly understood on a statewide level, and the potential for climate and land use change to affect carbon dynamics in Hawaii has not been formally assessed. We estimated current baseline and projected future ecosystem carbon stocks and fluxes on the seven main Hawaiian Islands using a combination of remote sensing, published plot-level data, and simulation modeling. Total ecosystem carbon storage during the baseline period was estimated at 258 TgC, with 70% stored as soil organic carbon, 25% as live biomass and 5% as surface detritus, and gross primary production was estimated at 20 TgC y-1. Net ecosystem carbon balance, which incorporated carbon losses from freshwater aquatic fluxes to nearshore waters and wildland fire emissions, was estimated as 0.34 TgC y-1 during the baseline period, offsetting 7% of anthropogenic emissions. We used a state and transition simulation model to estimate the response of ecosystem carbon stocks and fluxes to potential changes in climate, land use, and wildfire over a 50-year projection period (2012-2061). Total ecosystem carbon storage was projected to increase by 5% by the year 2061, but net ecosystem carbon balance was projected to decline by 35% due to climate change induced reductions in statewide net primary production and increased carbon losses from land use and land cover change. Our analysis indicates that the State of Hawaii would remain a net carbon sink overall, primarily because of ecosystem carbon sequestration on Hawaii Island, but predicted changes in climate and land use on Kauai and Oahu would convert these islands to net carbon sources. The Hawaii carbon assessment is part of a larger effort by the U.S. Geological Survey to assess the carbon sequestration potential of ecosystems across the United States and should provide valuable information for setting research and policy priorities for sustainable carbon management strategies aimed at offsetting anthropogenic carbon emissions.