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Sample records for estuarine system southern

  1. Assessing estuarine biota in southern California

    Treesearch

    Kevin D. Lafferty

    2005-01-01

    In southern California, most estuarine wetlands are gone, and what little habitat remains is degraded. For this reason, it is often of interest to assess the condition of estuaries over time, such as when determining the success of a restoration project. To identify impacts or opportunities for restoration, we also may want to know how a particular estuary, or area...

  2. Chamber-Based Estimates of Methane Production in Coastal Estuarine Systems in Southern California

    NASA Astrophysics Data System (ADS)

    Brigham, B.; Lipson, D.; Lai, C.

    2008-12-01

    Wetland systems are believed to produce between 100 - 231 Tg CH4 yr-1 which is roughly 20% of global methane emissions. The uncertainty in methane emissions models stem from the lack of detailed information about methane gas production within regional wetland systems. The aim of this study is to report the range of methane fluxes observed along salinity gradients at two San Diego coastal wetland systems, the Tijuana Estuary (Tijuana River National Estuarine Research Reserve) and the Peñasquitos Lagoon (Torrey Pines State Park Reserve). Soil water samples are used to elucidate factors responsible for the observed variation in methane fluxes. Air samples were subsequently collected from the headspace of a static soil chamber and stored in pre- evacuated vials. Methane concentrations were analyzed within hours after collection by gas chromatography in the laboratory. The chemical and physical properties of the soil, including salinity, pH, redox potential and temperature are measured with a hand-held probe nearby soil collars. The biological properties of the soil, including dissolved organic carbon, nitrate, and ammonia levels are measured from soil water samples in the laboratory. We find that saline sites under direct tidal influence produced methane fluxes ranging from -3.10 to 9.10 (mean 2.18) mg CH4 m-2 day-1. We also find that brackish sites (0.6 to 3.2 ppt in salinity) with fresh water input from residential runoff at the Peñasquitos Lagoon produced methane fluxes ranging from 0.53 to 192.10 (mean 33.34) mg CH4 m-2 day-1. Sampling was done over the course of 5 weeks during August-September of 2008. We hypothesize that the contrasting methane fluxes found between the saline and the brackish sites is due primarily to the different salinity, and in turn sulfate levels found at the two sites. The reduction of sulfate to produce energy is more energetically favorable than the reduction of carbon dioxide to produce methane. Thus the presence of sulfate may act as

  3. Baseline levels of oxidative stress biomarkers in species from a subtropical estuarine system (Paranaguá Bay, southern Brazil).

    PubMed

    Sardi, Adriana E; Renaud, Paul E; da Cunha Lana, Paulo; Camus, Lionel

    2016-12-15

    Offshore petroleum exploration has increased the risks of oil spills in coastal tropical and subtropical habitats. Monitoring tools are needed to assess and protect environmental health. We determined baseline values of antioxidant biomarkers (CAT, SOD, GPx, GST, MDA) for five ecologically relevant species in a subtropical system in southern Brazil. Regional baseline levels are compared with literature data as a basis to eventually test their efficacy as post-spill monitoring tools. Differences in the antioxidant response among species, contamination, and seasons were tested using univariate and multivariate analyses. The bivalves Anomalocardia flexuosa and Crassostrea rhizophorae and the catfish Genidens genidens emerge as suitable sentinel species. Seasonality is the main factor accounting for biomarkers variability, and not background contamination level. However, interactions between season and contamination level are also significant, indicating that biomarkers respond to complex environmental settings, a fact that needs to be fully understood for designing proper monitoring programs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. 75 FR 59696 - National Estuarine Research Reserve System

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-28

    ... National Oceanic and Atmospheric Administration National Estuarine Research Reserve System AGENCY... Approval and Availability of Revised Management Plans for the following National Estuarine Research... management plans of the Arraigns Bay, RI National Estuarine Research Reserve and the Tijuana River, CA...

  5. 75 FR 49887 - National Estuarine Research Reserve System

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-16

    ... National Oceanic and Atmospheric Administration National Estuarine Research Reserve System AGENCY... Period for Revised Management Plans for the following National Estuarine Research Reserves: Narragansett... management plans of the Narragansett Bay, RI National Estuarine Research Reserve and the Tijuana, CA National...

  6. Low mercury levels in marine fish from estuarine and coastal environments in southern China.

    PubMed

    Pan, Ke; Chan, Heidi; Tam, Yin Ki; Wang, Wen-Xiong

    2014-02-01

    This study is the first comprehensive evaluation of total Hg and methylmercury (MeHg) concentrations in wild marine fish from an estuarine and a coastal ecosystem in southern China. A total of 571 fish from 54 different species were examined. Our results showed that the Hg levels were generally low in the fish, and the Hg levels were below 30 ng g(-1) (wet weight) for 82% of the samples, which may be related to the reduced size of the fish and altered food web structure due to overfishing. Decreased coastal wetland coverage and different carbon sources may be responsible for the habitat-specific Hg concentrations. The degree of biomagnification was relatively low in the two systems.

  7. High genetic connectivity among estuarine populations of the riverbream Acanthopagrus vagus along the southern African coast

    NASA Astrophysics Data System (ADS)

    Oosthuizen, Carel J.; Cowley, Paul D.; Kyle, Scotty R.; Bloomer, Paulette

    2016-12-01

    Physical and/or physiological constraints are assumed to isolate fish populations confined to or dependent on estuarine habitats. Strong isolation by distance is thus expected to affect connectivity. Such structuring has important implications for sustainable utilisation and replenishment of estuarine stocks that are heavily exploited. Here we present a preliminary investigation of the phylogenetic relationships of the riverbream (Acanthopagrus species) along the southern African coast and the geographic genetic structure of what appears to be a locally endemic species or lineage. Mitochondrial DNA (mtDNA) cytochrome b sequences support the notion that the species occurring along the southern African coast is A. vagus and not A. berda as previously thought. Yet, the taxonomy of this widespread Indo-West Pacific species or species-complex requires more in-depth investigation. No genetic differentiation was detected among estuarine populations of A. vagus based on the analyses of mtDNA ND2 gene sequences and 10 polymorphic nuclear microsatellite markers. The star-like genealogy and statistical analyses are consistent with a recent population expansion event. Spatial analyses of microsatellite genotypes fail to reject the null hypothesis of panmixia, indicative of a recent population expansion or ongoing gene flow between different estuaries. The northern localities were identified as containing most of the observed variation. This study not only provides insight into the phylogenetic relationship of A. vagus relative to other Acanthopagrus species but also sheds light on the demographic history and contemporary gene flow of the species.

  8. Estuarine infill and coastal progradation, southern van diemen gulf, northern Australia

    NASA Astrophysics Data System (ADS)

    Woodroffe, C. D.; Mulrennan, M. E.; Chappell, J.

    1993-03-01

    There are several estuaries associated with the pronouncedly seasonal rivers which drain northwards from the Middle Proterozoic sandstone Arnhem Land plateau, and the Tertiary Koolpinyah land surface, into the macrotidal van Diemen Gulf, in the Northern Territory of Australia. The Holocene development of these, investigated in greatest detail for the South Alligator River with an upland catchment of > 10,000 km 2. through drilling, palynology and radiocarbon dating, comprises both estuarine infill and coastal progradation. Three phases of estuarine infill can be recognised: (i) a transgressive phase (8000-6800 years B.P.) of marine incursion; (ii) a big swamp phase (6800-5300 years B.P.) of widespread mangrove forest development; and (iii) a sinuous/cuspate phase of floodplain development since 5300 years B.P., during which the tidal river has meandered and reworked earlier estuarine sediments. Since 6000 years B.P., the South Alligator coastal plain has prograded at a decelerating rate, with two phases of chenier ridge formation. A similar pattern of estuarine infill, and decelerating coastal plain progradation, is demonstrated for the Adelaide and Mary Rivers, both with catchments of > 6000 km 2. The southern shore of van Diemem Gulf appears to have changed its overall position little during the last 2000 years. The major source for the clay, silt and fine sands which have infilled the estuary and coastal plain has been from seaward. Dispite the similarity of development, coastal sediment build up has had different effects on the morphology of each tidal river. The Adelaide has undergone a major diversion and no longer flows directly into van Diemen Gulf, but occupies a former fluvial course, and the Mary has been blocked entirely, and its former estuarine palaeochannels have been infilled with tide-transported sediment.

  9. Paleoenvironmental setting and description of an estuarine oyster reef in the Eocene of Patagonia, southern Argentina

    NASA Astrophysics Data System (ADS)

    Raising, Martín Rodríguez; Casadío, Silvio; Pearson, Nadine; Mángano, Gabriela; Buatois, Luis; Griffin, Miguel

    2014-12-01

    A middle Eocene Crassostrea sp. reef near Río Turbio, southwestern Patagonia (Argentina), represents the earliest record of an oyster reef associated with estuarine facies in the southern hemisphere, and also one of the few known worldwide occurring in Paleogene rocks. The reef grew in an outer estuary environment subject to periodic changes in salinity and may have reached a maturing phase. The Río Turbio reef - by its dimensions, geometry, and substrate lithology- would have been located in a tidal channel convergence area. This reef provides new evidence suggesting that estuaries served as refuges for Crassostrea populations allowing them to disperse into fully marine environments many times throughout the Cenozoic.

  10. 75 FR 60720 - National Estuarine Research Reserve System

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-01

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Estuarine Research Reserve System Correction In notice document 2010-24341 appearing on page 59696 in the issue of Tuesday, September 28, 2010 make the...

  11. 15 CFR 921.3 - National Estuarine Research Reserve System biogeographic classification scheme and estuarine...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE OCEAN AND COASTAL RESOURCE MANAGEMENT NATIONAL ESTUARINE... classification scheme based on regional variations in the nation's coastal zone has been developed. The...

  12. 15 CFR 921.3 - National Estuarine Research Reserve System biogeographic classification scheme and estuarine...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE OCEAN AND COASTAL RESOURCE MANAGEMENT NATIONAL ESTUARINE... classification scheme based on regional variations in the nation's coastal zone has been developed. The...

  13. 15 CFR 921.3 - National Estuarine Research Reserve System biogeographic classification scheme and estuarine...

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE OCEAN AND COASTAL RESOURCE MANAGEMENT NATIONAL ESTUARINE... classification scheme based on regional variations in the nation's coastal zone has been developed. The...

  14. 15 CFR 921.3 - National Estuarine Research Reserve System biogeographic classification scheme and estuarine...

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE OCEAN AND COASTAL RESOURCE MANAGEMENT NATIONAL ESTUARINE... classification scheme based on regional variations in the nation's coastal zone has been developed. The...

  15. 15 CFR 921.3 - National Estuarine Research Reserve System biogeographic classification scheme and estuarine...

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE OCEAN AND COASTAL RESOURCE MANAGEMENT NATIONAL ESTUARINE... classification scheme based on regional variations in the nation's coastal zone has been developed. The...

  16. Benthic infaunal community structuring in an acidified tropical estuarine system

    PubMed Central

    2014-01-01

    Background Recent studies suggest that increasing ocean acidification (OA) should have strong direct and indirect influences on marine invertebrates. While most theory and application for OA is based on relatively physically-stable oceanic ecological systems, less is known about the effects of acidification on nearshore and estuarine systems. Here, we investigated the structuring of a benthic infaunal community in a tropical estuarine system, along a steep salinity and pH gradient, arising largely from acid-sulphate groundwater inflows (Sungai Brunei Estuary, Borneo, July 2011- June 2012). Results Preliminary data indicate that sediment pore-water salinity (range: 8.07 - 29.6 psu) declined towards the mainland in correspondence with the above-sediment estuarine water salinity (range: 3.58 – 31.2 psu), whereas the pore-water pH (range: 6.47- 7.72) was generally lower and less variable than the estuarine water pH (range: 5.78- 8.3), along the estuary. Of the thirty six species (taxa) recorded, the polychaetes Neanthes sp., Onuphis conchylega, Nereididae sp. and the amphipod Corophiidae sp., were numerically dominant. Calcified microcrustaceans (e.g., Cyclopoida sp. and Corophiidae sp.) were abundant at all stations and there was no clear distinction in distribution pattern along the estuarine between calcified and non-calcified groups. Species richness increased seawards, though abundance (density) showed no distinct directional trend. Diversity indices were generally positively correlated (Spearman’s rank correlation) with salinity and pH (p <0.05) and negatively with clay and organic matter, except for evenness values (p >0.05). Three faunistic assemblages were distinguished: (1) nereid-cyclopoid-sabellid, (2) corophiid-capitellid and (3) onuphid- nereid-capitellid. These respectively associated with lower salinity/pH and a muddy bottom, low salinity/pH and a sandy bottom, and high salinity/pH and a sandy bottom. However, CCA suggested that species distribution

  17. Evidence of El Niño driven desiccation cycles in a shallow estuarine lake: The evolution and fate of Africa's largest estuarine system, Lake St Lucia

    NASA Astrophysics Data System (ADS)

    Humphries, M. S.; Green, A. N.; Finch, J. M.

    2016-12-01

    Projections of an increase in drought frequency and intensity over the next century are expected to have severe implications for a number of globally important coastal ecosystems. In this paper, we present geochemical data from three sediment cores extracted from the main depositional basins of Lake St Lucia, Africa's largest estuarine system. Lake St Lucia is subject to extreme natural variations in salinity. The sedimentary record documents the evolution of the system from a relatively deep-water, open lagoon to a confined, shallow estuarine lake that today is highly sensitive to changes in freshwater supply. This is particularly evident in the northern portions of the system, where the presence of distinct halite-enriched horizons document episodes of prolonged drought. The lateral persistence of these halite layers, as revealed by seismic profiling, point to a system-wide onset of desiccation associated with a major shift in the regional hydroclimate. The most severe drought events identified, which may have lasted several years, occur at 1100 and 1750 cal year BP, and are associated with known peaks in El Niño frequency and intensity. Our analyses suggest that past cycles of desiccation and hyper-salinity have been controlled by climatic changes related to ENSO intensification. This study provides a valuable new record from a key ENSO-sensitive region of the Southern Hemisphere. Our findings have important relevance for understanding ENSO variability across the Indo-Pacific region and the influence exerted on systems sensitive to changes in moisture balance.

  18. Metals contamination along the watershed and estuarine areas of southern Bohai Sea, China.

    PubMed

    Xu, Li; Wang, Tieyu; Ni, Kun; Liu, Shijie; Wang, Pei; Xie, Shuangwei; Meng, Jing; Zheng, Xiaoqi; Lu, Yonglong

    2013-09-15

    Distributions and magnitude of metals in water, sediment and soil collected from the watershed and estuarine areas of southern Bohai Sea, were investigated. The largest dissolved concentrations of As, Cu and Zn in water were 347.70, 2755.00, 2076.00 μg/L, respectively, much higher than corresponding drinking water guidelines. The greatest concentrations of Cu, Zn, Cr, Ni, Pb, As and Cd in sediments were 1462.2, 1602.17, 196.43, 67.15, 63.54, 73.86 and 1.41 mg/kg, dw, respectively. The mean concentrations of Cu, Ni, Cd, Zn, Cr, Pb and As in soils were 24.67, 24.73, 0.14, 64.75, 56.52, 25.12 and 9.34 mg/kg, dw, respectively. Land use was confirmed to be an important factor of influence on soil metal concentrations. Metal contents along the watershed of Jie River were significantly greater than in other locations. The detection of metals in relatively high concentrations from different environmental matrices in this region indicates the necessity of further studies. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. 77 FR 65533 - Proposed Information Collection; Comment Request; National Estuarine Research Reserve System...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-29

    ... definition, research design and implementation, and ultimately, application of the project results. This is... Estuarine Research Reserve System Science Collaborative Evaluation AGENCY: National Oceanic and Atmospheric... Estuarine Research Reserve System (NERRS) Science Collaborative was created in 2009 to put Reserve-based...

  20. Ecological and biological strategies of Etropus crossotus and Citharichthys spilopterus (Pleuronectiformes:Paralichthyidae) related to the estuarine plume, Southern Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Sánchez-Gil, Patricia; Yáñez-Arancibia, Alejandro; Tapia, Margarito; Day, John W.; Wilson, Charles A.; Cowan, James H., Jr.

    2008-04-01

    Differences in the biological and ecological strategies of two tropical flatfishes, Etropus crossotus (fringed flounder) and Citharichthys spilopterus (bay whiff) are discussed. The comparative analysis was based on the seasonal distribution of relative abundance of the two species and flatfish movements utilizing estuarine plume influenced areas as part of their life cycles. Growth parameters of the von Bertalanffy equation and recruitment were estimated (FISAT software) to compare life cycle patterns. The recruitment patterns illustrate the key difference between "estuarine-dependent" and "estuarine-related" nekton strategies. Both species have a short life cycle with a continuous recruitment activity. E. crossotus is an estuarine-related species, with two recruitment pulses ( winter frontal season), in the estuarine plume on the shelf. C. spilopterus is an estuarine-dependent species, with a main recruitment pulse during the rainy season in the estuarine plume, and a residual secondary pulse inside the adjacent estuarine system (Terminos Lagoon). The results show that the ecological success of these tropical coastal marine flatfish, with similar biological patterns, is based upon the sequential use (in time and space) of estuarine plume influenced habitats, suggesting that fish migration to shallow waters is related to food availability changes as a strategy towards optimum recruitment.

  1. Ecology of the Apalachicola Bay System: an estuarine profile

    SciTech Connect

    Livingston, R.J.

    1984-09-01

    Twelve years of studies in the Apalachicola Bay system are reviewed. Included are data on geography, hydrology, chemistry, geology, and biology. The system is part of a major drainage area including four rivers and associated wetlands in Georgia, Alabama, and Florida. It is a shallow coastal lagoon fringed by barrier islands and dominated by wind effects and tidal currents. River bottomlands (channels, sloughs, swamps, and backwater) and periodically flooded lowlands are important components. Principal influences on biological processes are basin physiography, river flow, nutrient input, and salinity. Water quality is affected by periodic wind and tidal influences and freshwater inflows. The system is in a relatively natural state, though hardly pristine. But economic development and population growth are beginning to threaten it. The area's economic and ecological importance as a food producer and shelter for diverse species has inspired a movement to protect its natural resources, including State and Federal land-purchase programs, integration of county land-use regulations into a comprehensive development, and creation of the Apalachicola River and Bay National Estuarine Sanctuary. 49 figs., 31 tabs.

  2. Seasonal and organ variations in antioxidant capacity, detoxifying competence and oxidative damage in freshwater and estuarine fishes from Southern Brazil.

    PubMed

    Da Rocha, A M; Salomão de Freitas, D P; Burns, M; Vieira, J P; de la Torre, F R; Monserrat, J M

    2009-11-01

    This study analyzed biochemical biomarkers of freshwater and estuarine fish species from Southern Brazil. It analyzed three organs (muscle, liver and gills), in four fish species (Micropogonias furnieri, Pimelodus pintado, Loricariichthys anus and Parapimelodus nigribarbis) in order to perform an environmental diagnosis. Obtained results showed that liver of L. anus and gills of M. furnieri presented higher total antioxidant capacity against peroxyl radicals during fall, whereas a clear seasonality was found for gill reduced glutathione (GSH) levels of all studied species, with higher concentration during spring. In terms of oxidative damage (TBARS), liver of M. furnieri and gills of P. nigribarbis showed higher TBARS levels during fall, whereas P. pintado showed the lowest TBARS value. Finally, a conspicuous seasonal effect was observed for purified and non-purified glutathione-S-transferase (GST), where minimum values were registered during fall, pointing to this season as one where fish species are less competent to perform detoxifying reactions.

  3. Determination of fish trophic levels in an estuarine system

    NASA Astrophysics Data System (ADS)

    Pasquaud, S.; Pillet, M.; David, V.; Sautour, B.; Elie, P.

    2010-01-01

    The concept of trophic level is particularly relevant in order to improve knowledge of the structure and the functioning of an ecosystem. A precise estimation of fish trophic levels based on nitrogen isotopic signatures in environments as complex and fluctuant as estuaries requires a good description of the pelagic and benthic trophic chains and a knowledge of organic matter sources at the bottom. In this study these points are considered in the case of the Gironde estuary (south west France, Europe). To obtain a good picture of the food web, fish stomach content analyses and a bibliographic synthesis of the prey feeding ecology were carried out. Fish trophic levels were calculated from these results and δ 15N data. The feeding link investigation enabled us to identify qualitatively and quantitatively the different preys consumed by each fish group studied, to distinguish the prey feeding on benthos from those feeding on pelagos and to characterize the different nutritive pools at the base of the system. Among the species studied, only Liza ramada and the flatfish ( Platichthys flesus and Solea solea) depend mainly on benthic trophic compartments. All the other fish groups depend on several trophic (benthic and/or pelagic) sources. These results enabled us to correct the calculation of fish trophic levels which are coherent with their feeding ecology data obtained from the nitrogen isotopic integrative period. The present work shows that trophic positions are linked with the feeding ecology of fish species and vary according to individual size. Ecological data also allow the correction of the isotopic data by eliminating absurd results and showing the complementarity of the two methods. This work is the first to consider source variability in the fish food web. This is an indispensable step for trophic studies in a dynamic environment. The investigation of matter fluxes and recycling processes at the food web base would provide a useful improvement in future

  4. Seafloor environments in the Long Island Sound estuarine system

    USGS Publications Warehouse

    Knebel, H. J.; Signell, R.P.; Rendigs, R. R.; Poppe, L.J.; List, J.H.

    1999-01-01

    Four categories of modern seafloor sedimentary environments have been identified and mapped across the large, glaciated, topographically complex Long Island Sound estuary by means of an extensive regional set of sidescan sonographs, bottom samples, and video-camera observations and supplemental marine-geologic and modeled physical-oceanographic data. (1) Environments of erosion or nondeposition contain sediments which range from boulder fields to gravelly coarse-to-medium sands and appear on the sonographs either as patterns with isolated reflections (caused by outcrops of glacial drift and bedrock) or as patterns of strong backscatter (caused by coarse lag deposits). Areas of erosion or nondeposition were found across the rugged seafloor at the eastern entrance of the Sound and atop bathymetric highs and within constricted depressions in other parts of the basin. (2) Environments of bedload transport contain mostly coarse-to-fine sand with only small amounts of mud and are depicted by sonograph patterns of sand ribbons and sand waves. Areas of bedload transport were found primarily in the eastern Sound where bottom currents have sculptured the surface of a Holocene marine delta and are moving these sediments toward the WSW into the estuary. (3) Environments of sediment sorting and reworking comprise variable amounts of fine sand and mud and are characterized either by patterns of moderate backscatter or by patterns with patches of moderate-to-weak backscatter that reflect a combination of erosion and deposition. Areas of sediment sorting and reworking were found around the periphery of the zone of bedload transport in the eastern Sound and along the southern nearshore margin. They also are located atop low knolls, on the flanks of shoal complexes, and within segments of the axial depression in the western Sound. (4) Environments of deposition are blanketed by muds and muddy fine sands that produce patterns of uniformly weak backscatter. Depositional areas occupy

  5. Improving the Representation of Estuarine Processes in Earth System Models

    NASA Astrophysics Data System (ADS)

    Sun, Q.; Whitney, M. M.; Bryan, F.; Tseng, Y. H.

    2016-12-01

    The exchange of freshwater between the rivers and estuaries and the open ocean represents a unique form of scale-interaction in the climate system. The local variability in the terrestrial hydrologic cycle is integrated by rivers over potentially large drainage basins (up to semi-continental scales), and is then imposed on the coastal ocean at the scale of a river mouth. Appropriately treating riverine freshwater discharge into the oceans in Earth system models is a challenging problem. Commonly, the river runoff is discharged into the ocean models with zero salinity and arbitrarily distributed either horizontally or vertically over several grid cells. Those approaches entirely neglect estuarine physical processes that modify river inputs before they reach the open ocean. A physically based Estuary Box Model (EBM) is developed to parameterize the mixing processes in estuaries. The EBM has a two-layer structure representing the mixing processes driven by tides and shear flow within the estuaries. It predicts the magnitude of the mixing driven exchange flow, bringing saltier lower-layer shelf water into the estuary to mix with river water prior to discharge to the upper-layer open ocean. The EBM has been tested against observations and high-resolution three-dimensional simulations of the Columbia River estuary, showing excellent agreement in the predictions of the strength of the exchange flow and the salinity of the discharged water, including modulation with the spring-neap tidal cycle. The EBM is implemented globally at every river discharge point of the Community Earth System Model (CESM). In coupled ocean-sea ice experiments driven by CORE surface forcing, the sea surface salinity (SSS) in the coastal ocean is increased globally compared to the standard model, contributing to a decrease in coastal stratification. The SSS near the mouths of some of the largest rivers is decreased due to the reduction in the area over which riverine fresh water is discharged. The

  6. Characterization Methods for Small Estuarine Systems in the Mid-Atlantic Region of the United States

    EPA Science Inventory

    Various statistical methods were applied to spatially discrete data from 14 intensively sampled small estuarine systems in the mid-Atlantic U.S. The number of sites per system ranged from 6 to 37. The surface area of the systems ranged from 1.9 to 193.4 km2. Parameters examined ...

  7. Characterization Methods for Small Estuarine Systems in the Mid-Atlantic Region of the United States

    EPA Science Inventory

    Various statistical methods were applied to spatially discrete data from 14 intensively sampled small estuarine systems in the mid-Atlantic U.S. The number of sites per system ranged from 6 to 37. The surface area of the systems ranged from 1.9 to 193.4 km2. Parameters examined ...

  8. Carbon and nitrogen isotope ratios of juvenile winter flounder as indicators of inputs to estuarine systems

    EPA Science Inventory

    Stable carbon and nitrogen isotope ratios were measured in the muscle tissues of young-of-the-year (YOY) winter flounder, Pseudopleuronectes americanus, collected from several estuarine systems along the coast of Rhode Island, USA. These systems included three coastal lagoons (Ni...

  9. Carbon and nitrogen isotope ratios of juvenile winter flounder as indicators of inputs to estuarine systems

    EPA Science Inventory

    Stable carbon and nitrogen isotope ratios were measured in the muscle tissues of young-of-the-year (YOY) winter flounder, Pseudopleuronectes americanus, collected from several estuarine systems along the coast of Rhode Island, USA. These systems included three coastal lagoons (Ni...

  10. Modern diatom assemblages as tools for paleoenvironmental reconstruction: a case study from estuarine intertidal zones in southern Iberia

    NASA Astrophysics Data System (ADS)

    Gomes, Ana; Boski, Tomasz; Moura, Delminda; Szkornik, Katie; Witkowski, Andrzej; Connor, Simon; Laut, Lazaro; Sobrinho, Frederico; Oliveira, Sónia

    2017-04-01

    Diatoms are unicellular algae that live in saline, brackish and freshwater environments, either floating in the water column or associated with various substrates (e.g., muddy and sandy sediments). Diatoms are sensitive to changes in environmental variables such as salinity, sediment texture, nutrient availability, light and temperature. This characteristic, along with their short lifespan, allows diatoms to quickly respond to environmental changes. Since the beginning of the 20th century, diatoms have been widely used to study the Holocene evolution of estuaries worldwide, particularly to reconstruct ecological responses to sea-level and climate changes. However, diatoms have been poorly studied in estuarine intertidal zones, due to the complexity of these environments, which have both fluvial and marine influences. The aim of this study was to understand diatom diversity and spatial distribution in intertidal zones from two geomorphologically and hydrologically distinct estuaries. Sediment samples were collected from within the intertidal zones along the Arade and Guadiana River estuaries in southern Iberia. The sampling points embraced almost all the tidal and salinity gradients of both estuaries, capturing the highest possible environmental variability and hence of diatom assemblages. At each sampling point, the salinity and pH of the sediment interstitial water were measured. The sediment samples were subdivided for diatom identification, textural analysis and organic matter determination. All sampling points were georeferenced by DGPS and the duration of tidal inundation was calculated for each site. Following diatom identification, the data were analysed statistically (i.e. cluster analysis, PCA, DCA and RDA). The present study revealed that there is a great diatom diversity in both estuaries (418 species), with several species new to science. The most important diatom species (with abundances higher or equal to 5%) occur in five ecological groups, which are

  11. NUTRIENT SOUIRCES, TRANSPORT, AND FATE IN COUPLED WATERSHED-ESTUARINE SYSTEMS OF COASTAL ALABAMA

    EPA Science Inventory

    The processes regulating sources, transport, and fate of nutrients were studied in 3 coupled watershed-estuarine systems that varied mainly by differences in the dominant land use-land cover (LULC), i.e. Weeks Bay -- agriculture, Dog River -- urban, and Fowl River -- forest. Mea...

  12. Aggregation, sedimentation, dissolution and bioavailability of quantum dots in estuarine systems.

    EPA Science Inventory

    To understand their fate and transport in estuarine systems, the aggregation, sedimentation, and dissolution of CdSe quantum dots (QDs) in seawater were investigated. Hydrodynamic size increased from 40 to 60 nm to >1 mm within 1 h in seawater, and the aggregates were highly p...

  13. NUTRIENT SOUIRCES, TRANSPORT, AND FATE IN COUPLED WATERSHED-ESTUARINE SYSTEMS OF COASTAL ALABAMA

    EPA Science Inventory

    The processes regulating sources, transport, and fate of nutrients were studied in 3 coupled watershed-estuarine systems that varied mainly by differences in the dominant land use-land cover (LULC), i.e. Weeks Bay -- agriculture, Dog River -- urban, and Fowl River -- forest. Mea...

  14. Aggregation, sedimentation, dissolution and bioavailability of quantum dots in estuarine systems.

    EPA Science Inventory

    To understand their fate and transport in estuarine systems, the aggregation, sedimentation, and dissolution of CdSe quantum dots (QDs) in seawater were investigated. Hydrodynamic size increased from 40 to 60 nm to >1 mm within 1 h in seawater, and the aggregates were highly p...

  15. Trace fossil assemblages in the tide-dominated estuarine system: Ameki Group, south-eastern Nigeria

    NASA Astrophysics Data System (ADS)

    Ekwenye, O. C.; Nichols, G.; Okogbue, C. O.; Mode, A. W.

    2016-06-01

    A systematic ichnological analysis with sedimentological study of the Eocene Ameki Group in south-eastern Nigeria, was conducted to infer depositional and biogenic processes operating during basin fill, identify discontinuities using substrate controlled ichnofacies, and identify the paleocological conditions that affected the diversity of the trace fossils. The Ameki Group represents a tide-dominated estuarine system characterised by a range of trace fossils assemblages. Eighteen individual ichnogenera and nineteen ichnospecies observed in the study area, were grouped into six recurring ichnofacies namely Scoyenia, Psilonichnus, Skolithos, Cruziana, Glossifungites and Teredolites. Skolithos and Cruziana ichnofacies are predominant in the estuarine deposits indicating that the sedimentary successions of the Eocene are dominantly of moderate to high energy marginal marine environments. The estuarine deposits (senus stricto) were controlled by low to fluctuating salinity levels, high sedimentation rate and fluctuating hydrodynamic energy. These resulted in the occurrence of low diversity of Scoyenia and Teredolites ichnofacies and low to moderate ichnodiversity of mixed Skolithos and depauperate Cruziana ichnofacies. Low levels of dissolved oxygen in quiescent water-embayment (open estuarine) resulted in low diversity of impoverished Cruziana ichnofacies. Glossifungites ichnofacies marked an amalgamated sequence boundary/marine flooding and an initial flooding surface at the base of the tidally influenced fluvial deposits.

  16. Nursery use patterns of commercially important marine fish species in estuarine systems along the Portuguese coast

    NASA Astrophysics Data System (ADS)

    Vasconcelos, R. P.; Reis-Santos, P.; Maia, A.; Fonseca, V.; França, S.; Wouters, N.; Costa, M. J.; Cabral, H. N.

    2010-03-01

    Analysing the estuarine use patterns of juveniles of marine migrant fish species is vital for identifying important sites for juveniles as well as the basic environmental features that characterize these sites for different species. This is a key aspect towards understanding nursery function. Various estuarine systems along the Portuguese coast (Minho, Douro, Ria de Aveiro, Mondego, Tejo, Sado, Mira, Ria Formosa and Guadiana) were sampled during Spring and Summer 2005 and 2006. Juveniles of commercially important marine fish species Solea solea, Solea senegalensis, Platichthys flesus, Diplodus vulgaris and Dicentrarchus labrax, predominantly 0-group individuals, were amongst the most abundant species and had distinct patterns of estuarine use as well as conspicuous associations with several environmental features. Juvenile occurrence and density varied amongst estuaries and sites within them, and differed with species. Sites with consistently high juvenile densities were identified as important juvenile sites (i.e. putative nursery grounds). Through generalized linear models (GLM), intra-estuarine variation in occurrence and density of each of the individual species was largely explained by environmental variables (temperature; salinity; depth; percentage of mud in the sediment; presence of seagrass; importance of intertidal areas; relative distance to estuary mouth; macrozoobenthos densities; and latitude). Decisive environmental factors defining important sites for juveniles varied depending on the system as a result of different environmental gradients, though there were common dominant features for each species regardless of the estuary considered. Analysed environmental variables in the GLM also accounted for inter-estuarine variation in species' occurrence and density. In several estuaries, the identified important juvenile sites were used by many of these species simultaneously and may be of increased value to both management and conservation. Overall, the

  17. Southern Pine Beetle Information System (SPBIS)

    Treesearch

    Valli Peacher

    2011-01-01

    The southern pine beetle (SPB) is the most destructive forest insect in the South. The SPB attacks all species of southern pine, but loblolly and shortleaf are most susceptible. The Southern Pine Beetle Information System (SPBIS) is the computerized database used by the national forests in the Southern Region for tracking individual southern pine beetle infestations....

  18. ESTIMATION OF INHERENT OPTICAL PROPERTIES AND THE WATER QUALITY COMPONENTS IN THE NEUSE RIVER-PAMLICO SOUND ESTUARINE SYSTEM

    EPA Science Inventory

    Field observations carried out in the Neuse River-Pamlico Sound Estuarine System (NRE-PS), North Carolina, USA were used to develop optical algorithms for assessing inherent optical properties, IOPs (absorption and backscattering) associated with water quality components (WQC).

  19. ESTIMATION OF INHERENT OPTICAL PROPERTIES AND THE WATER QUALITY COMPONENTS IN THE NEUSE RIVER-PAMLICO SOUND ESTUARINE SYSTEM

    EPA Science Inventory

    Field observations carried out in the Neuse River-Pamlico Sound Estuarine System (NRE-PS), North Carolina, USA were used to develop optical algorithms for assessing inherent optical properties, IOPs (absorption and backscattering) associated with water quality components (WQC).

  20. Sponge-rhodolith interactions in a subtropical estuarine system

    NASA Astrophysics Data System (ADS)

    Ávila, Enrique; Riosmena-Rodríguez, Rafael; Hinojosa-Arango, Gustavo

    2013-06-01

    The interactions between sponges and red macroalgae have been widely documented in tropical and subtropical environments worldwide, and many of them have been documented as mutualistic associations. Sponges, however, have also been frequently described as part of the associated fauna of rhodolith habitats (aggregations of free-living non-geniculated coralline macroalgae). Nonetheless, the types of interaction they establish as well as the role of sponges in these habitats remain unknown. In this study, the associations between sponges and rhodoliths were investigated in an estuarine ecosystem of the Mexican Pacific based on qualitative and quantitative data. A total of 13 sponge species were identified in five newly discovered rhodolith beds dominated by the non-geniculate coralline macroalga Lithophyllum margaritae. The sponge assemblages were strongly restricted to rhodolith habitats. The best predictor of sponge abundance (from 5.1 to 51.7 ind m-2) and species richness (from 2.6 to 6.1 sponge species m-2) was the rhodolith density rather than other population descriptors assessed (e.g., average size, branch density and sphericity). The identified sponges included a variety of forms: massive (46 %), encrusting (23 %), excavating (15 %), cushion-shape (8 %) and digitate (8 %). Moreover, more than 50 % of sponge species recorded (mainly massive and encrusting forms) were frequently found overgrowing and binding rhodoliths. Halichondria cf. semitubulosa and Mycale cecilia were the most common binding agents; these species bind an average of 3.1 and 6.6 rhodoliths per sponge individual, respectively. These findings reveal the importance of rhodoliths as habitat forming species, since these seaweed beds notably increased the substrate complexity in soft bottom environments. In addition, the relatively high abundance of sponges and their capability to bind rhodoliths suggest that these associated organisms could have an important contribution to rhodolith bed stability.

  1. Modeling fecal coliform contamination in a tidal Danshuei River estuarine system.

    PubMed

    Liu, Wen-Cheng; Chan, Wen-Ting; Young, Chih-Chieh

    2015-01-01

    A three-dimensional fecal coliform transport model was developed and incorporated into a hydrodynamic model to obtain a better understanding of local microbiological water quality in the tidal Danshuei River estuarine system of northern Taiwan. The model was firstly validated with the salinity and fecal coliform data measured in 2010. The concentration comparison showed quantitatively good agreement between the simulation and measurement results. Further, the model was applied to investigate the effects of upstream freshwater discharge variation and fecal coliform loading reduction on the contamination distributions in the tidal estuarine system. The qualitative and quantitative analyses clearly revealed that low freshwater discharge resulted in higher fecal coliform concentration. The fecal coliform loading reduction considerably decreased the contamination along the Danshuei River-Tahan Stream, the Hsintien Stream, and the Keelung River.

  2. Distribution of butyltin compounds in Brazil's southern and southeastern estuarine ecosystems: assessment of spatial scale and compartments.

    PubMed

    Dos Santos, Dayana Moscardi; Turra, Alexander; de Marchi, Mary Rosa Rodrigues; Montone, Rosalinda Carmela

    2016-08-01

    Butyltin compounds (BTs), including tributyltin (TBT) and its degradation products, dibutyltin and monobutyltin, have been found in a diversity of aquatic systems and causing toxic effects in target and nontarget organisms. They enter in coastal systems through different sources (as antifouling paints, industrial effluents, etc.) where they interact with biotic and abiotic components, and their distribution is commonly determined by the morphological and hydrodynamic conditions of the coastal systems. In this study, we discuss the contamination by BTs on a spatial scale (eight estuaries with three subareas each) and in different compartments of the estuaries (sediments, suspended particulate matter (SPM), and estuarine catfish tissues (liver and gills). Lower concentrations of BTs were found in the sediments (n.d. to 338 ng g(-1)) in comparison to studies before a ban of TBT in antifouling paints was enacted, mostly indicating an old input or preservation related with sediment properties and composition. For SPM samples (n.d. to 175 ng L(-1)) as well as in fish tissues (n.d. to 1426 ng g(-1)), the presence of these compounds was frequent, especially in the fish due to their movement throughout the estuaries and the potential to assess point sources of BTs. These results indicate that BTs persist in the environment, with variation in amounts between investigated estuaries and even at locations inside the same estuary, because of ideal preservation conditions, transport to remote areas, and input from different sources.

  3. Shoreline Erosion in the Albemarle-Pamlico Estuarine System, Northeastern North Carolina

    NASA Astrophysics Data System (ADS)

    Murphy, M. A.; Riggs, S. R.

    2002-12-01

    Computer analysis of aerial photographic series demonstrates that the estuarine shorelines within the North Carolina Albemarle-Pamlico coastal system are eroding at 2-3 times greater rates than previous studies reported. Specific rates and amounts of shoreline recession vary tremendously depending upon local variables including: 1) shoreline type, geometry, and composition; 2) geographic location, size, and shape of associated estuary; 3) frequency, intensity, and fetch of storms; 4) type and abundance of associated vegetation; and locally 5) boat wakes. Organic or wetland shorelines (marsh and swamp forest) comprise approximately 62% of the estuarine margins in NE NC, whereas sediment banks (low, high, and bluff) constitute about 38%. The goals of this study were to determine the rates of recession for different shoreline types and the role of local variables in the erosion process. Shorelines were mapped using high precision GPS mapping techniques, digital orthographic quarter quadrangles, and other georeferenced aerial photographs from the early 1950's to 2001. Shoreline change was then calculated for 20 estuarine study sites. Field mapping of each site provided data on shoreline characteristics and erosional processes. Data synthesis suggests mean annual shoreline erosion rates are significantly different for shoreline types as follows: 1) marshes = 7.4 ft/yr (range 2.7-17.0 ft/yr), low sediment banks = 5.0 ft/yr (range 1.0-12.0 ft/yr), bluff sediment banks = 5.0 ft/yr (range = 3.9-6.0 ft/yr), swamp forests = 3.0 ft/yr (range = 1.7-4.0 ft/yr), high sediment banks = 2.8 ft/yr (range = 2.7-2.9 ft/yr). Modified shorelines continue to erode, however at lower mean annual rates that range from 0.9-2.7 ft/yr. Locally, specific marsh shorelines have eroded at rates up to 100 ft/yr during particularly stormy periods. Thus, about 1166 acres of land are lost each year along the 1593 miles of mapped estuarine shoreline in NE NC. If these erosion rates are representative of

  4. Chemical partitioning and bioavailability of lead and nickel in an estuarine system

    SciTech Connect

    Babukutty, Y.; Chacko, J.

    1995-03-01

    Sediments, water, and biota of an estuarine system were analyzed for concentrations of lead and nickel. Sediments were sequentially extracted to obtain the different chemically extractable fractions (exchangeable, carbonate bound, Fe/Mn-oxide bound, organically bound, and residual fractions) of these metals. Concentrations of these metals in the soft tissue of an estuarine bivalve Villorita cyprinoides var. cochinensis were correlated with the concentrations of these metals present in the various sediment fractions, dissolved, and particulate phases in water. The degree of correlation between these various environmental variables and biological factors was considered as the index of bioavailability. Metal concentrations in the soft tissue and particulate phase of water were divided by the corresponding concentrations in the dissolved phase in water to obtain the bioconcentration ratio (BCR) and metal partitioning ratio (MPR), respectively. These ratios were found to be useful in quantifying the metal bioavailability. The relationship between other biological factors and environmental variables is also presented and discussed.

  5. Study of pollutant distribution in the Guaxindiba Estuarine System--SE Brazil.

    PubMed

    Fonseca, E M; Baptista Neto, J A; Pereira, M P S; Silva, C G; Arantes, J D

    2014-05-15

    The Guaxindiba Estuarine System is located in the northeast portion of Guanabara Bay. Despite the location inside an environmental protection zone, the main affluent of the river runs through the extremely urbanized area of the cities of Niterói and São Gonçalo. In order to understand the contamination levels of the estuary, 35 surface sediment samples were collected along the river and estuarine area and analyzed for the presence of heavy metals, PAHs, organochlorated pesticides, polychlorinated biphenyl and other contaminants. The analyzed data revealed a greatly affected environment with respect to most of these substances. The results suggested propitious deposits of contaminants, with high concentrations of organic matter and fine sediment. The levels of heavy metal in the entire estuarine system were high compared with the local background. The total mean concentrations of As, Cd, Pb, Cu, Zn, Hg, Cr and Ni in the surface sediments were: 3.74; 0.03; 19.3; 15.0; 99.0; n.d.; 29.0; and 22.0mg/kg, respectively, confirming, in certain cases, the high capacity of the environment to concentrate pollution.

  6. Spatial patterns of fish communities along two estuarine gradients in southern Florida

    USGS Publications Warehouse

    Green, D.P.J.; Trexler, J.C.; Lorenz, J.J.; McIvor, C.C.; Philippi, T.

    2006-01-01

    In tropical and subtropical estuaries, gradients of primary productivity and salinity are generally invoked to explain patterns in community structure and standing crops of fishes. We documented spatial and temporal patterns in fish community structure and standing crops along salinity and nutrient gradients in two subtropical drainages of Everglades National Park, USA. The Shark River drains into the Gulf of Mexico and experiences diurnal tides carrying relatively nutrient enriched waters, while Taylor River is more hydrologically isolated by the oligohaline Florida Bay and experiences no discernable lunar tides. We hypothesized that the more nutrient enriched system would support higher standing crops of fishes in its mangrove zone. We collected 50 species of fish from January 2000 to April 2004 at six sampling sites spanning fresh to brackish salinities in both the Shark and Taylor River drainages. Contrary to expectations, we observed lower standing crops and density of fishes in the more nutrient rich tidal mangrove forest of the Shark River than in the less nutrient rich mangrove habitats bordering the Taylor River. Tidal mangrove habitats in the Shark River were dominated by salt-tolerant fish and displayed lower species richness than mangrove communities in the Taylor River, which included more freshwater taxa and yielded relatively higher richness. These differences were maintained even after controlling for salinity at the time of sampling. Small-scale topographic relief differs between these two systems, possibly created by tidal action in the Shark River. We propose that this difference in topography limits movement of fishes from upstream marshes into the fringing mangrove forest in the Shark River system, but not the Taylor River system. Understanding the influence of habitat structure, including connectivity, on aquatic communities is important to anticipate effects of construction and operational alternatives associated with restoration of the

  7. Salt-marsh areas as copper complexing ligand sources to estuarine and coastal systems.

    PubMed

    Santos-Echeandía, Juan; Caetano, Miguel; Laglera, Luis M; Vale, Carlos

    2013-01-01

    Dissolved copper levels, copper complexing capacities and conditional stability constants have been determined in the Tagus estuarine waters and one of the saltmarshes located in this estuary, the Rosario saltmarsh. Tagus estuarine waters show a constant and around 20 nM copper concentration during the estuarine mixing. Most of this copper is organically complexed by a strong ligand (L(1)) with a concentration that varies between 19 and 55 nM and a log K' between 14.14 and 15.75. In addition L(1)/Cu ratios are quite constants and close to 1 all through the estuary, indicating the same source. A second and weaker ligand (L(2)) was also detected in these waters in higher concentrations (36-368 nM) but with a lower log K' that varies between 12.06 and 13.13. The present work has demonstrated that salt-marsh areas are important and continuous sources of copper complexing ligands to the Tagus estuary. Noticeable, tidal induced transport continuously feed these waters with copper and ligands, mainly with the stronger one. This continuous input, together with the high residence times of this system results in a quite constant concentration along the salinity gradient. This input represents 95% of the ligand present in the estuary. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Back-barrier and seabed sediment dynamics in the Albemarle-Pamlico estuarine system, North Carolina

    NASA Astrophysics Data System (ADS)

    Walsh, J. P.; Corbett, D. R.

    2016-02-01

    Estuaries are critical habitats as well as places where people live, recreate, and make their livelihood. Additionally, they are sites where land and sea interact, and sediments, and associated pollutants and carbon, are deposited, remobilized and accumulated. Many processes, such as river discharge, waves, tides, and sea-level rise, are operating in estuaries to cause sediment dynamics, impacting humans and organisms as a result. Recent research we have been engaged in across the Albemarle-Pamlico Estuarine System (APES) has investigated the sediments dynamics of this important estuary. The APES is the second largest estuary in the continental United States, consisting of the Albemarle and Pamlico sounds and the Pamlico River and Neuse River sub-estuaries. Although expansive in size, the system is shallow with minimal tidal range. Water and sediment discharge into the APES is modest, and the existence of few inlets along the Outer Banks limits mixing with the Atlantic Ocean. Human impact on the drainage basin and estuarine system is moderate and increasing over time. Over the last five years, a considerable volume of sedimentary process data has been collected over various timescales and locations in the APES. More specifically, work has included: deployments of instrumented tripods to examine seabed dynamics; collection and analysis of shallow cores and GIS investigation of aerial photographs and other data. This wealth of data highlights several insights: 1) shorelines are generally eroding ( 0.25 m/y and rapidly >3 m/y in places), but rates are temporally and spatially variable; 2) seabed resuspension is frequent, yet net accumulation of 2-4 mm/y is widespread in deeper locations; and 3) storms cause episodic, localized impacts (e.g., barrier breaches) on this large, shallow estuarine system.

  9. Modeling hydrodynamics of large lagoons: Insights from the Albemarle-Pamlico Estuarine System

    NASA Astrophysics Data System (ADS)

    Clunies, Gregory J.; Mulligan, Ryan P.; Mallinson, David J.; Walsh, J. P.

    2017-04-01

    Large estuaries are influenced by winds over adjacent coastal ocean and land areas causing significant spatial variations in water levels, currents and surface waves. In this study we apply a numerical model to simulate hydrodynamics and waves in the Albemarle-Pamlico Estuarine System, a large and shallow back-barrier basin in eastern North Carolina, over a one-month study period (September 2008) with observations from several storm wind events of differing time scales and directions. Model performance is evaluated for a spatially varying wind field from the North American Regional Reanalysis (NARR) dataset in comparison to spatially uniform forcing from wind observations at offshore, coastal and land-based sites across the region. A spatially uniform wind field from offshore winds observations results in statistically better hydrodynamic simulations of water levels (R = 0.88) in the estuaries than NARR (R = 0.48) after comparison with measurements and indicates the importance of strong marine winds over most of the estuary surface area. The influence of a prominent bathymetric feature on hydrodynamics in Pamlico Sound is also investigated by numerically removing a 30 km long and 2-3 m deep shoal from the model grid and replacing it with an idealized depth of 6 m. The removal of the shoal increases water level setup by 14% at the estuarine shoreline, decreases current magnitudes by up to 40% in the shoal region and increases significant wave heights locally by up to 25% in the sound, indicating the importance of this relict geomorphic feature as a major control on the hydrodynamic response of the system during wind events. The results suggest that increasing the water depth over the shoal can lead to higher storm surges and wave heights with the possibility of increased inundation and erosion of the back-barrier and mainland coastal regions. The complex bathymetry and marine wind influence are critical input conditions for modeling large and shallow lagoonal

  10. A box model for representing estuarine physical processes in Earth system models

    NASA Astrophysics Data System (ADS)

    Sun, Qiang; Whitney, Michael M.; Bryan, Frank O.; Tseng, Yu-heng

    2017-04-01

    Appropriately treating riverine freshwater discharge into the oceans in Earth system models is a challenging problem. Commonly, the river runoff is discharged into the ocean models with zero salinity and arbitrarily distributed either horizontally or vertically over several grid cells. Those approaches entirely neglect estuarine physical processes that modify river inputs before they reach the open ocean. In order to realistically represent riverine freshwater inputs in Earth system models, a physically based Estuary Box Model (EBM) is developed to parameterize the mixing processes in estuaries. The EBM represents the estuary exchange circulation with a two-layer box structure. It takes as input the river volume flux from the land surface model and the subsurface salinity at the estuary mouth from the ocean model. It delivers the estuarine outflow salinity and net volume flux into and out of the estuary to the ocean model. An offline test of the EBM forced with observed conditions for the Columbia River system shows good agreement with observations of outflow salinity and high-resolution simulations of the exchange flow volume flux. To illustrate the practicality of use of the EBM in an Earth system model, the EBM is implemented for all coastal grid cells with river runoff in the Community Earth System Model (CESM). Compared to the standard version of CESM, which treats runoff as an augmentation to precipitation, the EBM increases sea surface salinity and reduces stratification near river mouths. The EBM also leads to significant regional and remote changes in CESM ocean surface salinities.

  11. ESTUARINE HAZARD ASSESSMENT IN THE PENSACOLA BAY SYSTEM

    EPA Science Inventory

    ersonnel from the Gulf Ecology Division have conducted a multiyear evaluation of the environmental condition of areas in the Pensacola Bay System affected by point and nonpoint contamination. Areas of study included coastal rivers, residential canals, bayous and bays impacted by ...

  12. Photochemical and microbial alterations of DOM spectroscopic properties in the estuarine system Ria de Aveiro.

    PubMed

    Santos, L; Santos, E B H; Dias, J M; Cunha, A; Almeida, A

    2014-08-01

    The influence of photochemical transformations of chromophoric dissolved organic matter (CDOM) on microbial communities was evaluated in the estuarine system Ria de Aveiro. Two sites, representative of the marine and brackish water zones of the estuary, were surveyed regularly in order to determine seasonal and vertical profiles of variation of CDOM properties. Optical parameters of CDOM indicative of aromaticity and molecular weight were used to establish CDOM sources, and microbial abundance and activity was characterized. Additionally, microcosm experiments were performed in order to simulate photochemical reactions of CDOM and to evaluate microbial responses to light-induced changes in CDOM composition. The CDOM of the two estuarine zones showed different spectral characteristics, with significantly higher values of the specific ultra-violet absorbance at 254 nm (SUVA254) (5.5 times) and of the absorption coefficient at 350 nm (a350) (12 times) and lower SR (S275-295/S350-400) ratio at brackish water compared with the marine zone, reflecting the different amounts and prevailing sources of organic matter, as well as distinct riverine and oceanic influences. At the marine zone, the abundance of bacteria and the activity of Leu-AMPase correlated with a350 and a254, suggesting a microbial contribution to the HMW CDOM pool. The irradiation of DOM resulted in a decrease of the values of a254 and a350 and an increase of the slope S275-295 and of the ratios E2 : E3 (a250/a365) and SR, which in turn increase its bioavailability. However, the extent of photoinduced transformations and microbial responses was dependent on the initial optical characteristics of CDOM. In Ria de Aveiro both photochemical and microbial processes yielded optical changes in CDOM and the overall results of these combined processes determine the fate of CDOM in the estuarine system and have an influence on local productivity and in adjacent coastal areas.

  13. Human impacts on morphodynamic thresholds in estuarine systems

    NASA Astrophysics Data System (ADS)

    Wang, Z. B.; Van Maren, D. S.; Ding, P. X.; Yang, S. L.; Van Prooijen, B. C.; De Vet, P. L. M.; Winterwerp, J. C.; De Vriend, H. J.; Stive, M. J. F.; He, Q.

    2015-12-01

    Many estuaries worldwide are modified, primarily driven by economic gain or safety. These works, combined with global climate changes heavily influence the morphologic development of estuaries. In this paper, we analyze the impact of human activities on the morphodynamic developments of the Scheldt Estuary and the Wadden Sea basins in the Netherlands and the Yangtze Estuary in China at various spatial scales, and identify mechanisms responsible for their change. Human activities in these systems include engineering works and dredging activities for improving and maintaining the navigation channels, engineering works for flood protection, and shoreline management activities such as land reclamations. The Yangtze Estuary is influenced by human activities in the upstream river basin as well, especially through the construction of many dams. The tidal basins in the Netherlands are also influenced by human activities along the adjacent coasts. Furthermore, all these systems are influenced by global changes through (accelerated) sea-level rise and changing weather patterns. We show that the cumulative impacts of these human activities and global changes may lead to exceeding thresholds beyond which the morphology of the tidal basins significantly changes, and loses its natural characteristics. A threshold is called tipping point when the changes are even irreversible. Knowledge on such thresholds or tipping points is important for the sustainable management of these systems. We have identified and quantified various examples of such thresholds and/or tipping points for the morphodynamic developments at various spatial and temporal scales. At the largest scale (mega-scale) we consider the sediment budget of a tidal basin as a whole. A smaller scale (macro-scale) is the development of channel structures in an estuary, especially the development of two competing channels. At the smallest scale (meso-scale) we analyze the developments of tidal flats and the connecting

  14. Dynamics of mercury species in surface sediments of a macrotidal estuarine-coastal system (Adour River, Bay of Biscay)

    NASA Astrophysics Data System (ADS)

    Stoichev, T.; Amouroux, D.; Wasserman, J. C.; Point, D.; De Diego, A.; Bareille, G.; Donard, O. F. X.

    2004-03-01

    Estuarine and coastal surface sediments from the Adour estuary and adjacent coastal area (South Bay of Biscay) have been investigated to establish mercury species variability in a macrotidal system submitted to contrasted seasonal river discharges and downstream urbanisation. Surface sediments were sampled during three campaigns in the major sediment deposits of the Adour estuary and at selected discharge points. Concentrations of Hg 2+ and MeHg + in Adour estuarine sediments average 1600 and 1.3 pmol g -1, and range from <2 to 7300 pmol g -1 and from <0.5 to 8.0 pmol g -1, respectively. The concentrations of inorganic ionic mercury (Hg 2+) and monomethylmercury (MeHg +) in the surface sediments display large seasonal variation, being one order of magnitude higher in June 2001 for Hg 2+ and in October 2000 for MeHg +. The results show that Hg 2+ can be accumulated in the estuarine sediments after seasonal river inputs and both remobilised and methylated during dry period. Mercury species concentrations in coastal sediments collected in June 2001 assessed the impact of estuarine inputs on the nearby coastal area. Except direct anthropogenic discharge points, the variability and transfer of Hg 2+ and MeHg + in surface sediments of the whole estuarine-coastal macrotidal system can be depicted by simple geochemical parameters of the bulk sediments, such as grain size distribution, organic carbon and total sulphur.

  15. The Southern Annual Forest Inventory System

    Treesearch

    Gregory A. Reams; Paul C. van Deusen

    1999-01-01

    The Southern Annual Forest Inventory System (SAFIS) is in various stages of implementation in 7 of the 13 southern states serviced by the Southern Research Station. The SAFIS design is an interpenetrating design where the n units (1/6 acre plots) are divided into k = 5 panels, each panel containing m = n...

  16. Modelling of cohesive sediment dynamics in tidal estuarine systems: Case study of Tagus estuary, Portugal

    NASA Astrophysics Data System (ADS)

    Franz, G.; Pinto, L.; Ascione, I.; Mateus, M.; Fernandes, R.; Leitão, P.; Neves, R.

    2014-12-01

    Cohesive sediment dynamics in estuarine systems is a major issue in water quality and engineering problems. Numerical models can help to assess the complex dynamics of cohesive sediments, integrating the information collected in monitoring studies. Following a numerical approach we investigated the main factors that influence the cohesive sediment dynamics in an estuarine system composed of large mudflats (Tagus estuary, Portugal). After a spin up period of the bottom layer and considering the combined effect of waves and currents on the bottom shear stress, the dynamics of cohesive sediment during the fortnightly and daily erosion-sedimentation cycle was properly reproduced by the model. The results of cohesive suspended sediments were validated with data from sixteen monitoring stations located along the estuary and turbidity data measured by two multiparametric probes. The hydrodynamics were previously validated by harmonic analysis and with ADCP data. Although tidal currents are the major cause of cohesive sediment erosion, the results suggest that wind waves also play an important role. The simulated sediment mass involved in the fortnightly tidal cycle was in the same order of magnitude of the annual load from the rivers, as observed in previous studies based on field data.

  17. Maps showing textural characteristics of benthic sediments in the Corpus Christi Bay estuarine system, south Texas

    USGS Publications Warehouse

    Shideler, Gerald L.; Stelting, Charles E.; McGowen, Joseph H.

    1981-01-01

    Corpus Christi Bay is a heavily used estuary on the south Texas coast in the northwest Gulf of Mexico (fig. 1).  The Bay is stressed by diverse activities which could substantially affect its ecosystem.  Such activities include shipping, resource production (oil, gas, and construction aggregate), commercial and sport fishing, and recreation.  Shipping activities alone have had a substantial impact on the bay.  For example, the past maintenance of navigation channels has required extensive dredging and spoil disposal within the estuarine system.  Numerous subaqueous spoil disposal sites and subaerial spoil banks are present throughout the bay (fig. 1), and the selection of future spoil disposal sites is becoming a critical local problem.  As activities in the bay increase, the need for effective environmental management becomes increasingly important, and effective management necessitates a good understanding of the bay's physical characteristics.  The objective of this study is to provide detailed information about the textural composition of bottom sediments within the estuarine system, information which could be used in making environmental-management decisions.  Visual descriptions of bottom sediments in Corpus Christi Bay and adjacent areas have been presented by McGowen and Morton (1979).  Additionally, a study of the textures of sediments on the Inner Continental Shelf adjacent to the bay has been presented by Shideler and Berryhill (1977).

  18. Habitat and hydrology: assessing biological resources of the Suwannee River Estuarine System

    USGS Publications Warehouse

    Raabe, Ellen A.; Edwards, Randy E.; McIvor, Carole C.; Grubbs, Jack W.; Dennis, George D.

    2007-01-01

    The U.S. Geological Survey conducted a pilot integrated-science study during 2002 and 2003 to map, describe, and evaluate benthic and emergent habitats in the Suwannee River Estuary on the Gulf Coast of Florida. Categories of aquatic, emergent, and terrestrial habitats were determined from hyperspectral imagery and integrated with hydrologic data to identify estuarine fish habitats. Maps of intertidal and benthic habitat were derived from 12-band, 4-m resolution hyperspectral imagery acquired in September 2002. Hydrologic data were collected from tidal creeks during the winter of 2002-03 and the summer-fall of 2003. Fish were sampled from tidal creeks during March 2003 using rivulet nets, throw traps, and seine nets. Habitat characteristics, hydrologic data, and fish assemblages were compared for tidal creeks north and south of the Suwannee River. Tidal creeks north of the river had more shoreline edge and shallow habitat than creeks to the south. Tidal creeks south of the river were generally of lower salinity (fresher) and supported more freshwater marsh and submerged aquatic vegetation. The southern creeks tended to be deeper but less sinuous than the northern creeks. Water quality and inundation were evaluated with hydrologic monitoring in the creeks. In-situ gauges, recording pressure and temperature, documented a net discharge of brackish to saline groundwater into the tidal creeks with pronounced flow during low tide. Groundwater flow into the creeks was most prominent north of the river. Combined fish-sampling results showed an overall greater abundance of organisms and greater species richness in the southern creeks, nominally attributed a greater range in water quality. Fish samples were dominated by juvenile spot, grass shrimp, bay anchovy, and silverside. The short time frame for hydrologic monitoring and the one-time fish-sampling effort were insufficient for forming definitive conclusions. However, the combination of hyperspectral imagery and

  19. Linking DNRA community structure and activity in a shallow lagoonal estuarine system

    PubMed Central

    Song, Bongkeun; Lisa, Jessica A.; Tobias, Craig R.

    2014-01-01

    Dissimilatory nitrate reduction to ammonium (DNRA) and denitrification are two nitrate respiration pathways in the microbial nitrogen cycle. Diversity and abundance of denitrifying bacteria have been extensively examined in various ecosystems. However, studies on DNRA bacterial diversity are limited, and the linkage between the structure and activity of DNRA communities has yet to be discovered. We examined the composition, diversity, abundance, and activities of DNRA communities at five sites along a salinity gradient in the New River Estuary, North Carolina, USA, a shallow temporal/lagoonal estuarine system. Sediment slurry incubation experiments with 15N-nitrate were conducted to measure potential DNRA rates, while the abundance of DNRA communities was calculated using quantitative PCR of nrfA genes encoding cytochrome C nitrite reductase, commonly found in DNRA bacteria. A pyrosequencing method targeting nrfA genes was developed using an Ion Torrent sequencer to examine the diversity and composition of DNRA communities within the estuarine sediment community. We found higher levels of nrfA gene abundance and DNRA activities in sediments with higher percent organic content. Pyrosequencing analysis of nrfA genes revealed spatial variation of DNRA communities along the salinity gradient of the New River Estuary. Percent abundance of dominant populations was found to have significant influence on overall activities of DNRA communities. Abundance of dominant DNRA bacteria and organic carbon availability are important regulators of DNRA activities in the eutrophic New River Estuary. PMID:25232351

  20. Impact of freshwater inflow on bacterial abundance and activity in the estuarine system Ria de Aveiro

    NASA Astrophysics Data System (ADS)

    Santos, Luísa; Vaz, Leandro; Marcial Gomes, Newton C.; Vaz, Nuno; Dias, João Miguel; Cunha, Ângela; Almeida, Adelaide

    2014-02-01

    The influence of freshwater flow on bacterial communities in the estuarine system Ria de Aveiro (Portugal) was investigated at two sites differently impacted by river inputs, representative of the marine and brackish water zones of the estuary. Sampling events were clustered based on hydrological features. The hydrodynamic was simulated with a Lagrangian model and related to microbiological parameters. Estuarine bacteria responded to different freshwater regimes developing distinct patterns of abundance and activity at the marine and brackish water zones. A circulation pattern induced by high river inflow produced vertical stratification in the marine zone, promoting a seaward flux of bacterioplankton, and stimulating the import of riverine phytoplankton and particle-attached bacteria to the brackish water zone. Advective transport and resuspension processes contributed to a 3-times increase in abundance of particle-attached bacteria during intense freshwater inputs. Additionally, bacterial activity in the estuary was controlled by inorganic nitrogen, responding to different freshwater inputs, which, in association with different prevailing sources of organic substrates induced significant changes in bacterial production. The dynamic and main controlling factors of bacterial communities are clearly impacted by freshwater inputs. Therefore, significant changes in the recycling of nutrients by microbial activities can be expected from alterations in freshwater inputs either related to global climate change or regional hydrological regimes.

  1. Skill assessment of an integrated modeling system for shallow coastal and estuarine ecosystems

    NASA Astrophysics Data System (ADS)

    Sheng, Y. Peter; Kim, Taeyun

    2009-02-01

    The predictive skills of an integrated physical-biogeochemical modeling system (CH3D-IMS) for shallow estuarine and coastal ecosystems are assessed using available field data in the Indian River Lagoon estuarine system, Florida during 1998-2000. The cornerstone of the modeling system is the circulation model CH3D (Curvilinear-grid Hydrodynamics in 3D), which is coupled to models of wave (SMB), sediment transport, water quality (nutrients: N, P, and Si, three phytoplankton species, zooplankton, and dissolved oxygen), light attenuation, and seagrass. To resolve the complex geometry and bathymetry of the estuarine system, the modeling system uses a boundary-fitted non-orthogonal curvilinear grid in the horizontal direction and a terrain-following sigma grid in the vertical direction. While water level and salinity data were collected continuously (at 15-min intervals) at 10 fixed stations, most water quality data were collected at much longer time scales (bi-weekly to quarterly) during ship surveys at more than 30 stations. Sediment-water quality data were collected at 24 stations once in 1998. Model skills for hydrodynamic and water quality simulations are assessed in terms of the absolute relative errors and the relative operating characteristic (ROC) scores. Both methods indicate that the modeling system has skills in simulating water level, salinity, dissolved oxygen, chlorophyll, and dissolved nutrients, with the ROC score between 0.6 and 0.862, indicating skills for most of the variables. Skills for simulating total suspended solids (TSS) and particulate nutrients are lacking, with ROC score and: between 0.5-0.6. Simulated diffuse attenuation coefficient, which depends on TSS, chlorophyll a, and dissolved organic matter, has an ROC of 0.55. Using high frequency time-varying field data collected during two episodic events in the study period, the skills of CH3D-IMS improved significantly for both TSS and particulate nutrients. Model skills for particulate

  2. Blue carbon in human-dominated estuarine and shallow coastal systems.

    PubMed

    Kuwae, Tomohiro; Kanda, Jota; Kubo, Atsushi; Nakajima, Fumiyuki; Ogawa, Hiroshi; Sohma, Akio; Suzumura, Masahiro

    2016-04-01

    Estuarine and shallow coastal systems (ESCS) are recognized as not only significant organic carbon reservoirs but also emitters of CO2 to the atmosphere through air-sea CO2 gas exchange, thus posing a dilemma on ESCS's role in climate change mitigation measures. However, some studies have shown that coastal waters take up atmospheric CO2 (Catm), although the magnitude and determinants remain unclear. We argue that the phenomenon of net uptake of Catm by ESCS is not unusual under a given set of terrestrial inputs and geophysical conditions. We assessed the key properties of systems that show the net Catm uptake and found that they are often characteristic of human-dominated systems: (1) input of high terrestrial nutrients, (2) input of treated wastewater in which labile carbon is highly removed, and (3) presence of hypoxia. We propose that human-dominated ESCS are worthy of investigation as a contributor to climate change mitigation.

  3. Development of an estuarine assessment scheme for the management of a highly urbanised catchment/estuary system, Sydney estuary, Australia.

    PubMed

    Birch, G F; Gunns, T J; Chapman, D; Harrison, D

    2016-05-01

    As coastal populations increase, considerable pressures are exerted on estuarine environments. Recently, there has been a trend towards the development and use of estuarine assessment schemes as a decision support tool in the management of these environments. These schemes offer a method by which complex environmental data is converted into a readily understandable and communicable format for informed decision making and effective distribution of limited management resources. Reliability and effectiveness of these schemes are often limited due to a complex assessment framework, poor data management and use of ineffective environmental indicators. The current scheme aims to improve reliability in the reporting of estuarine condition by including a concise assessment framework, employing high-value indicators and, in a unique approach, employing fuzzy logic in indicator evaluation. Using Sydney estuary as a case study, each of the 15 sub-catchment/sub-estuary systems were assessed using the current scheme. Results identified that poor sediment quality was a significant issue in Blackwattle/Rozelle Bay, Iron Cove and Hen and Chicken Bay while poor water quality was of particular concern in Duck River, Homebush Bay and the Parramatta River. Overall results of the assessment scheme were used to prioritise the management of each sub-catchment/sub-estuary assessed with Blackwattle/Rozelle Bay, Homebush Bay, Iron Cove and Duck River considered to be in need of a high priority management response. A report card format, using letter grades, was employed to convey the results of the assessment in a readily understood manner to estuarine managers and members of the public. Letter grades also provide benchmarking and performance monitoring ability, allowing estuarine managers to set improvement targets and assesses the effectiveness of management strategies. The current assessment scheme provides an effective, integrated and consistent assessment of estuarine health and

  4. Nitrogen Isotope Ratios of Juvenile Winter Flounder as an Indicator of Anthropogenic Nitrogen Inputs to Estuarine Systems

    EPA Science Inventory

    Nitrogen isotope ratios (15N) were measured in muscle tissue of juvenile winter flounder, Pseudopleuronectes americanus, collected from several estuarine systems (lagoons, river, bay) along the coast of Rhode Island, USA over a three-year period. Significant differences i...

  5. Trends in nitrogen isotope ratios of juvenile winter flounder reflect changing nitrogen inputs to Rhode Island, USA estuarine systems

    EPA Science Inventory

    Nitrogen isotope ratios (d 15N) in juvenile winter flounder, Pseudopleuronectes americanus, were used to examine changes in nitrogen inputs to several Rhode Island, USA estuarine systems. Fish were collected over two three-year periods with a ten-year interval between sampling pe...

  6. Nitrogen Isotope Ratios of Juvenile Winter Flounder as an Indicator of Anthropogenic Nitrogen Inputs to Estuarine Systems

    EPA Science Inventory

    Nitrogen isotope ratios (15N) were measured in muscle tissue of juvenile winter flounder, Pseudopleuronectes americanus, collected from several estuarine systems (lagoons, river, bay) along the coast of Rhode Island, USA over a three-year period. Significant differences i...

  7. Literature assessment of the Charlotte Harbor estuarine system and surrounding area, Southwest Florida

    USGS Publications Warehouse

    Stoker, Yvonne E.; Karavitis, George A.

    1983-01-01

    The Governor of Florida established the Charlotte Harbor Resource Planning and Management committee to recommend the course of action Florida should take in planning for potential growth in the rapidly growing area surrounding Charlotte Harbor. In May 1981, the U.S. Geological Survey began a planning study to determine detailed hydrologic study needs of the Charlotte Harbor area. A literature search of available data and reports pertaining to the Charlotte Harbor estuarine system and surrounding area resulted in almost 1,300 references. This report contains all references collected during this search. Some of the major reference topics are altered freshwater flow, water quality of the harbor and drainage systems, circulation and tides, coastal and marine resources, fisheries, geology and hydrology of the area, impact studies, water resources, flora and fauna of the area, and water supply. Sixty-eight key words or subject identifiers are used to the index report. (USGS)

  8. Impact of a major cyclone on a southeast African estuarine lake system

    NASA Astrophysics Data System (ADS)

    Forbes, A. T.; Cyrus, D. P.

    The St Lucia lake and estuarine system in northern Natal, South Africa was struck by Cyclone Domoina on 31 January 1984. This is the only cyclone known to have traversed part of South Africa. The ensuing flood levels in the St Lucia system (which have been exceeded perhaps only one other time in recorded history) provided an opportunity to assess the effect of a major disturbance on a subtropical estuarine system. Major geomorphological changes occurred in the mouth area where all man-made structures were obliterated. The two river channels were scoured from 2-3 m to 10-14 m in depth and widened by up to 300 m, while the shoreline between the two channels retreated in places up to 100 m. An estimated 16∗10 6 m 3 of sediment were removed from the lower reaches of the system including areas of mangrove and Phragmites australis swamp. One-metre tall mangrove saplings died following inundation lasting days to weeks. Effects on the fauna included redistribution of the tanaid Apseudes digitalis, the mysid Mesopodopsis africana, the copepod Pseudodiaptomus stuhlmanni, the polychaete Scololepis squamata and the bivalve Solen cylindraceus, all typical lake species which appeared in the tidal channel linking the lake with the sea. Responses of other species such as the penaeid prawns, the crab Scylla serrata and the sole Solea bleekeri suggested that physiological tolerance, extended larval or juvenile recruitment periods and prey switching minimized long-term flood effects. No large-scale mortalities were noted, and the absence of a temperature shock is considered to be a significant feature.

  9. A General Solution for Groundwater Flow in Estuarine Leaky Aquifer System with Considering Aquifer Anisotropy

    NASA Astrophysics Data System (ADS)

    Chen, Po-Chia; Chuang, Mo-Hsiung; Tan, Yih-Chi

    2014-05-01

    In recent years the urban and industrial developments near the coastal area are rapid and therefore the associated population grows dramatically. More and more water demand for human activities, agriculture irrigation, and aquaculture relies on heavy pumping in coastal area. The decline of groundwater table may result in the problems of seawater intrusion and/or land subsidence. Since the 1950s, numerous studies focused on the effect of tidal fluctuation on the groundwater flow in the coastal area. Many studies concentrated on the developments of one-dimensional (1D) and two-dimensional (2D) analytical solutions describing the tide-induced head fluctuations. For example, Jacob (1950) derived an analytical solution of 1D groundwater flow in a confined aquifer with a boundary condition subject to sinusoidal oscillation. Jiao and Tang (1999) derived a 1D analytical solution of a leaky confined aquifer by considered a constant groundwater head in the overlying unconfined aquifer. Jeng et al. (2002) studied the tidal propagation in a coupled unconfined and confined costal aquifer system. Sun (1997) presented a 2D solution for groundwater response to tidal loading in an estuary. Tang and Jiao (2001) derived a 2D analytical solution in a leaky confined aquifer system near open tidal water. This study aims at developing a general analytical solution describing the head fluctuations in a 2D estuarine aquifer system consisted of an unconfined aquifer, a confined aquifer, and an aquitard between them. Both the confined and unconfined aquifers are considered to be anisotropic. The predicted head fluctuations from this solution will compare with the simulation results from the MODFLOW program. In addition, the solutions mentioned above will be shown to be special cases of the present solution. Some hypothetical cases regarding the head fluctuation in costal aquifers will be made to investigate the dynamic effects of water table fluctuation, hydrogeological conditions, and

  10. Coastal wetland response to sea-level rise in a fluvial estuarine system

    NASA Astrophysics Data System (ADS)

    Alizad, Karim; Hagen, Scott C.; Morris, James T.; Medeiros, Stephen C.; Bilskie, Matthew V.; Weishampel, John F.

    2016-11-01

    Coastal wetlands are likely to lose productivity under increasing rates of sea-level rise (SLR). This study assessed a fluvial estuarine salt marsh system using the Hydro-MEM model under four SLR scenarios. The Hydro-MEM model was developed to apply the dynamics of SLR as well as capture the effects associated with the rate of SLR in the simulation. Additionally, the model uses constants derived from a 2-year bioassay in the Apalachicola marsh system. In order to increase accuracy, the lidar-based marsh platform topography was adjusted using Real Time Kinematic survey data. A river inflow boundary condition was also imposed to simulate freshwater flows from the watershed. The biomass density results produced by the Hydro-MEM model were validated with satellite imagery. The results of the Hydro-MEM simulations showed greater variation of water levels in the low (20 cm) and intermediate-low (50 cm) SLR scenarios and lower variation with an extended bay under higher SLR scenarios. The low SLR scenario increased biomass density in some regions and created a more uniform marsh platform in others. Under intermediate-low SLR scenario, more flooded area and lower marsh productivity were projected. Higher SLR scenarios resulted in complete inundation of marsh areas with fringe migration of wetlands to higher land. This study demonstrated the capability of Hydro-MEM model to simulate coupled physical/biological processes across a large estuarine system with the ability to project marsh migration regions and produce results that can aid in coastal resource management, monitoring, and restoration efforts.

  11. Tidal regime and morphodynamic changes in estuarine systems as a function of sea-level rise

    NASA Astrophysics Data System (ADS)

    Mallinson, D. J.; Culver, S. J.; Mulligan, R.; Leorri, E.; Mitra, S.; Riggs, S. R.; Moran, K.

    2011-12-01

    Tidal amplitude and currents along coastlines will change in conjunction with sea-level rise, when certain geomorphic and bathymetric conditions are met. Under conditions of decreasing protection from barrier islands, associated with increased inlet activity or overstepping of islands, tidal amplitude can rapidly increase in estuaries and along mainland coastlines and significantly amplify the effects of a minor sea-level rise. Impacts to coastal systems may be economically and environmentally significant. Additionally, sea-level curves developed from areas where tidal regime change has occurred in the past must be evaluated carefully for the effects of tidal amplitude. The impacts of tidal amplitude changes in response to sea-level rise have been noted in the Minas Basin, Delaware Bay, and, in this study, the Albemarle-Pamlico Estuarine System of North Carolina. Our group is investigating the magnitude of changes in response to variations in geomorphic and bathymetric conditions, and past climate events. Methods include the use of seismic data, sedimentology, microfossil analysis, oxygen isotopes, Mg/Ca, black carbon, and radiocarbon ages to reconstruct paleobathymetry, paleoenvironments and paleoclimate conditions during the late Holocene. Paleobathymetric/paleogeomorphic models are being derived to enable hydrodynamic modeling using Delft3D software. Initial runs for the Pamlico Sound have been performed to reconstruct hydrodynamic conditions during a barrier break-down event associated with the Medieval Climate Anomaly (ca. 1000 cal yr BP). Likewise, models are being used to understand hydrodynamics in the Currituck Sound (a smaller lagoon in northeastern NC) in response to historical inlet activity. Results illustrate the potential for an eight-fold increase in tidal amplitude, with significant variations within the estuarine system, and large increases in tidal currents well into the estuaries, resulting in significant changes to salinity structures and

  12. THE PACIFIC COAST ESTUARINE INFORMATION SYSTEM: CREATING A BASELINE FOR THE FUTURE

    EPA Science Inventory

    Coastal researchers and managers have a growing need for ready access to a diversity of
    data types, including estuarine-specific lists of native and nonindigenous species and estuarine/landscape characteristics. These data are key components in ecological risk assessments in g...

  13. THE PACIFIC COAST ESTUARINE INFORMATION SYSTEM: CREATING A BASELINE FOR THE FUTURE

    EPA Science Inventory

    Coastal researchers and managers have a growing need for ready access to a diversity of
    data types, including estuarine-specific lists of native and nonindigenous species and estuarine/landscape characteristics. These data are key components in ecological risk assessments in g...

  14. Seasonal distribution of aliphatic hydrocarbons in the Vaza Barris Estuarine System, Sergipe, Brazil.

    PubMed

    Barbosa, José Carlos S; Santos, Lukas G G V; Sant'Anna, Mércia V S; Souza, Michel R R; Damasceno, Flaviana C; Alexandre, Marcelo R

    2016-03-15

    The seasonal assessment of anthropogenic activities in the Vaza Barris estuarine river system, located in the Sergipe state, northeastern Brazil, was performed using the aliphatic hydrocarbon distribution. The aliphatic hydrocarbon and isoprenoid (Pristane and Phytane) concentrations ranged between 0.19 μg g(-1) and 8.5 μg g(-1) of dry weight. Data were analyzed using Kruskal-Wallis test, with significance level set at p<0.05, and no seasonality distribution change was observed. The Carbon Preference Index (CPI), associated with n-alkanes/n-C16, Low Molecular Weight/High Molecular Weight ratio (LMW/HMW) and Terrigenous to Aquatic Ratio (TAR) suggested biogenic input of aliphatic hydrocarbons for most samples, with significant contribution of higher plants. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Late Quaternary in a South Atlantic estuarine system: Stratigraphic and paleontologic indicators of coastal evolution

    NASA Astrophysics Data System (ADS)

    Aliotta, Salvador; Ginsberg, Silvia S.; Spagnuolo, Jorge O.; Farinati, Ester; Giagante, Darío; Vecchi, Laura G.

    2013-08-01

    The decisive influence of Late Quaternary sea level changes on the geological evolution of the coastal plain and adjacent continental shelf around the world has long been recognized. Coastal environments evolve actively during transgressive-regressive cycles whose development depends on sea level and sediment supply variations. The interaction of these variables was key to the current morphological and sedimentological configuration of coastal regions. Particularly, the estuarine system of Bahía Blanca (Argentina) presents various types of deposits and marine fossil accumulations, such as paleochannels in the subbottom, sand-shell ridges and extensive layers with fossils in life position. These features are important geological indicators, because its analysis allows us to define different paleoenvironmental conditions that prevailed during the coastal evolutionary process.

  16. The ichthyofauna of limnic systems in Quaternary deposits of extreme southern Brazil

    PubMed Central

    Assumpção, Cindy M.; Quintela, Fernando M.; Corrêa, Fabiano; Loebmann, Daniel

    2016-01-01

    Abstract The Quaternary in the state of Rio Grande do Sul (RS), southern Brazil, is geologically represented by the coastal plain and was originated by successive events of Pleistocene-Holocene marine transgressions and the occurrence of alluvial deposits. This paper aimed to characterize the fish assemblage occurring in a swampy Quaternary area adjacent to Lagoa Pequena, a lacustrine system connected to the west margin of the Laguna dos Patos estuary. A checklist is also provided of the ichthyofauna so far recorded in limnic systems of Quaternary deposits in the state of Rio Grande do Sul. A total of 42 species was recorded, distributed in nine orders, 18 families and 31 genera. Characidae and Cichlidae were the most representative families, comprising 15 and 4 species respectively. A bibliographic revision associated to our sample data revealed the occurrence of 156 species in limnic systems inserted in RS Quaternary deposits (114 limnic, 15 marine/estuarine/limnic, ten marine/estuarine, nine estuarine/limnic and eight marine). Characiformes and Siluriformes are the most diverse orders, corroborating the Neotropical pattern. Seven species can be considered endemic to RS Quaternary deposits. PMID:28174498

  17. The ichthyofauna of limnic systems in Quaternary deposits of extreme southern Brazil.

    PubMed

    Assumpção, Cindy M; Quintela, Fernando M; Corrêa, Fabiano; Loebmann, Daniel

    2016-01-01

    The Quaternary in the state of Rio Grande do Sul (RS), southern Brazil, is geologically represented by the coastal plain and was originated by successive events of Pleistocene-Holocene marine transgressions and the occurrence of alluvial deposits. This paper aimed to characterize the fish assemblage occurring in a swampy Quaternary area adjacent to Lagoa Pequena, a lacustrine system connected to the west margin of the Laguna dos Patos estuary. A checklist is also provided of the ichthyofauna so far recorded in limnic systems of Quaternary deposits in the state of Rio Grande do Sul. A total of 42 species was recorded, distributed in nine orders, 18 families and 31 genera. Characidae and Cichlidae were the most representative families, comprising 15 and 4 species respectively. A bibliographic revision associated to our sample data revealed the occurrence of 156 species in limnic systems inserted in RS Quaternary deposits (114 limnic, 15 marine/estuarine/limnic, ten marine/estuarine, nine estuarine/limnic and eight marine). Characiformes and Siluriformes are the most diverse orders, corroborating the Neotropical pattern. Seven species can be considered endemic to RS Quaternary deposits.

  18. 15 CFR 921.51 - Estuarine research guidelines.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 15 Commerce and Foreign Trade 3 2010-01-01 2010-01-01 false Estuarine research guidelines. 921.51... MANAGEMENT NATIONAL ESTUARINE RESEARCH RESERVE SYSTEM REGULATIONS Special Research Projects § 921.51 Estuarine research guidelines. (a) Research within the National Estuarine Research Reserve System shall be...

  19. 15 CFR 921.51 - Estuarine research guidelines.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 15 Commerce and Foreign Trade 3 2012-01-01 2012-01-01 false Estuarine research guidelines. 921.51... MANAGEMENT NATIONAL ESTUARINE RESEARCH RESERVE SYSTEM REGULATIONS Special Research Projects § 921.51 Estuarine research guidelines. (a) Research within the National Estuarine Research Reserve System shall...

  20. Estuarine Food for Thought

    NASA Astrophysics Data System (ADS)

    M�ller-Solger, A. B.; M�ller-Navarra, D. B.

    2002-12-01

    Recent research in animal and human nutrition has shown the importance of long-chain polyunsaturated fatty acids (LC-PUFA) such as the n-3 LC-PUFA eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These LC-PUFA are needed for healthy development and functioning of the nervous and vascular systems. De novo synthesis or elongation to LC-PUFA in animals is inefficient at best; thus sufficient amounts of these PUFA must be supplied by food sources. Algae, especially diatoms, dinoflagellates, and cryptophytes, are the quantitatively most important producers of EPA and DHA. These types of algae often dominate estuarine producer communities. The upper San Francisco Estuary is no exception, and we found its LC-PUFA-rich phytoplankton biomass, but not the quantitatively prevalent terrestrial plant detritus, to be highly predictive of zooplankton (Daphnia) growth. In contrast, in freshwater lakes dominated by relatively LC-PUFA-poor phytoplankton, EPA, not total phytoplankton biomass, best predicted Daphnia growth. The commonly high abundance of LC-PUFA-rich algae in estuaries may help explain the high trophic efficiencies in these systems and resulting high consumer production. Moreover, LC-PUFA-rich estuarine food resources may also provide essential nutrition and associated health and evolutionary benefits to land-dwelling consumers of such foods, including humans. Ensuring LC-PUFA-rich, uncontaminated estuarine production is thus an important goal for estuarine restoration and a convincing argument for estuarine conservation.

  1. Tracing coastal and estuarine groundwater discharge sources in a complex faulted and fractured karst aquifer system

    NASA Astrophysics Data System (ADS)

    Lagomasino, D.; Price, R. M.

    2013-05-01

    Groundwater discharge can be an important input of water, nutrients and other constituents to coastal wetlands and adjacent marine areas, particularly in karst regions with little to no surface water flow. A combination of natural processes (e.g., sea-level rise and climate change) and anthropogenic pressures (e.g., urban growth and development) can alter the subterranean water flow to the coastline. For water management practices and environmental preservation to be better suited for the natural and human environment, a better understanding is needed of the hydrogeologic connectivity between the areas of fresh groundwater recharge and the coastal zone. The Yucatan peninsula has a unique tectonic and geologic history consisting of a Cretaceous impact crater, Miocene and Eocene tectonic plate movements, and multiple sea-level stands. These events have shaped many complex geologic formations and structures. The Sian Káan Biosphere Reserve (SKBR), a UNESCO World Heritage Site located along the Atlantic Ocean, overlaps two distinct hydrogeologic regions: the evaporate region to the south and south west, and the Holbox Fracture Zone to the north. These two regions create a complex network of layered, perched and fractured aquifers and an extensive groundwater cave network. The two regions are distinguished by bedrock mineralogical differences that can be used to trace shallow subsurface water from interior portions of the peninsula to the Bahia de la Ascension in the SKBR. The objective of this research was to use naturally occurring geochemical tracers (eg., Cl-, SO42-, HCO3-, K+, Mg2+, Na+, Ca2+ and stable isotopes of oxygen and hydrogen) to decipher the sources of groundwater flow through the coastal wetlands of the SKBR and into the Bahia de la Ascension. Surface water and groundwater samples were collected during two field campaigns in 2010 and 2012 within the coastal and estuarine waters of the SKBR. Additional water samples were collected at select cenotes along

  2. Description and distribution of two new species of Paraonidae (Annelida: Polychaeta) from a lagoon-estuarine ecosystem in the Southern Gulf of Mexico.

    PubMed

    Arriaga-Hernández, Stefan; Hernández-Alcántara, Pablo; Solís-Weiss, Vivianne

    2013-01-01

    The aim of this study was to analyze the taxonomy and distribution of the polychaetes of the family Paraonidae from a lagoon-estuarine ecosystem in the Gulf of Mexico. The samples come from 20 soft bottom stations in the Términos Lagoon during the dry and rainy seasons, of which eight included paraonids. In all, 1183 specimens belonging to two new species were identified: Aricidea (Acmira) hirsuta (1125 specimens) and Paradoneis carmelitensis (58 specimens). A. (A.) hirsuta is clearly distinguished from other members of the genus by the presence of unidentate curved spines with a dense pubescence along their medium and distal margins, and because the median antenna is short. P carmelitensis is mainly characterized by the absence of eyes, by the presence of triangular shaped postchaetal prebranchial lobes, and the presence of branchiae and lyriform chaetae from chaetiger 4. The paraonids occurrence was mainly associated with salinities close to marine conditions (31.71 to 35.85 psu). They were almost totally collected during the rainy season (1178 specimens from both species) in the central and southern areas; during the dry season only five specimens of P. carmelitensis were recorded.

  3. In-situ measurements of Cu in an estuarine environment using a portable spectrophotometric analysis system.

    PubMed

    Callahan, Michael R; Kaltenbacher, Eric A; Byrne, Robert H

    2004-01-15

    Application of a portable in-situ spectrophotometric analysis system for the measurement of Cu in estuarine environments is described in this work. Our spectrophotometric elemental analysis system (SEAS) used for in-situ observations of Cu concentrations is capable of fully autonomous or user-controlled operations. The optical cells used in SEAS systems are flexible liquid core waveguides (LCWs) with optical path lengths as long as 5 m. The 1-m waveguide used in the present study provided a 3.0 nM detection limit and a 5.0% relative standard deviation for a 25 nM copper sample. Analysis times range between 1 and 5 min, allowing for acquisition of data on scales appropriate to the highly dynamic biogeochemical nature of copper in the coastal environment. Field deployments of SEAS-Cu in Tampa Bay, FL, showed low Cu concentrations near the mouth of the estuary (3-4 nM), with elevated concentrations (approximately 25 nM) in anthropogenically impacted regions of the bay (e.g., marinas and areas adjacent wastewater treatment plants). Transect data between Tampa Bay and a deep water harborage exhibited copper concentrations ranging between 5 and 50 nM.

  4. Nutrient fluctuations in the Quatipuru river: A macrotidal estuarine mangrove system in the Brazilian Amazonian basin

    NASA Astrophysics Data System (ADS)

    Pamplona, Fábio Campos; Paes, Eduardo Tavares; Nepomuceno, Aguinaldo

    2013-11-01

    The temporal and spatial variability of dissolved inorganic nutrients (NO3-, NO2-, NH4+, PO43- and DSi), total nitrogen (TN), total phosphorus (TP), nutrient ratios, suspended particulate matter (SPM) and Chlorophyll-a (Chl-a) were evaluated for the macrotidal estuarine mangrove system of the Quatipuru river (QUATIES), east Amazon coast, North Brazil. Temporal variability was assessed by fortnightly sampling at a fixed station within the middle portion of the estuary, from November 2009 to November 2010. Spatial variability was investigated from two field surveys conducted in November 2009 (dry season) and May 2010 (rainy season), along the salinity gradient of the system. The average DIN (NO3- + NO2- + NH4+) concentration of 9 μM in the dry season was approximately threefold greater in comparison to the rainy season. NH4+ was the main form of DIN in the dry season, while NO3- predominated in the rainy season. The NH4+ concentrations in the water column during the dry season are largely attributed to release by tidal wash-out of the anoxic interstitial waters of the surficial mangrove sediments. On the other hand, the higher NO3- levels during the wet season, suggested that both freshwater inputs and nitrification processes in the water column acted in concert. The river PO43- concentrations (DIP < 1 μM) were low and similar throughout the year. DIN was thus responsible for the major temporal and spatial variability of the dissolved DIN:DIP (N:P) molar ratios and nitrogen corresponded, in general, to the prime limiting nutrient for the sustenance of phytoplankton biomass in the estuary. During the dry season, P-limitation was detected in the upper estuary. PO43- adsorption to SPM was detected during the rainy season and desorption during the dry season along the salinity gradient. In general, the average Chl-a level (14.8 μg L-1) was 2.5 times higher in the rainy season than in the dry season (5.9 μg L-1). On average levels reached maxima at about 14 km from

  5. Radioactive impact in sediments from an estuarine system affected by industrial wastes releases.

    PubMed

    Bolívar, Juan Pedro; García-Tenorio, Rafael; Mas, José Luis; Vaca, Federico

    2002-03-01

    A big fertilizer industrial complex and a vast extension of phosphogypsum piles (12 km2), sited in the estuary formed by the Odiel and Tinto river mouths (southwest of Spain), are producing an unambiguous radioactive impact in their surrounding aquatic environment through radionuclides from the U-series. The levels and distribution of radionuclides in sediments from this estuarine system have been determined. The analyses of radionuclide concentrations and activity ratios have provided us with an interesting information to evaluate the extension, degree and routes of the radioactive impact, as well as for the knowledge of the different pathways followed for the radioactive contamination to disturb this natural system. The obtained results indicate that the main pathway of radioactive contamination of the estuary is through the dissolution in its waters of the radionuclides released by the industrial activities and their later fixation on the particulate materials. Tidal activity also plays an important role in the transport and homogenization along the estuary of the radioactivity released from the fertilizer plants.

  6. Meiobenthos assemblages in the mekong estuarine system with special focus on free-living marine nematodes

    NASA Astrophysics Data System (ADS)

    Quang, Ngo Xuan; Vanreusel, Ann; Smol, Nic; Chau, Nguyen Ngoc

    2010-12-01

    Meiobenthos assemblages in eight estuaries of the Mekong river system were investigated in August 2008 (from the Cua Tieu estuary to the Tran De estuary). In each estuary, one sampling station was established for meiobenthos sampling. Twelve major taxa of meiobenthos were recorded in this estuarine system, including Nematoda, Copepoda, Turbellaria, Polychaeta, Oligochaeta, Tardigrada, Bivalvia, Ostracoda, Amphipoda, Cumacea, Gastrotricha, Gastropoda, and Crustacean Nauplii larvae. The densities of the meiobenthos range from 581 to 3168 inds/10 cm2. Nematodes always occupy the highest numbers with a percentage ranging from 64-99%. There are 135 nematode genera recorded in this study with the following as dominant genera Desmodora, Leptolaimus, Halalaimus, Thalassomonhystera, Theristus, Daptonema, Rhynchonema, Parodontophora, and Oncholaimus. Although the biodiversity of the meiobenthos at higher taxa level is not high compared to other marine environments, the estimates of nematode biodiversity at the genus level indicates high values. The increase in number of genera with increasing sampling intensity illustrate that the diversity is underestimated and would have been higher if the authors had considered a larger number of individuals, more replicates per station, and more sampling stations.

  7. Foraminiferal Distributions, Sedimentation Rates and Patterns in the Albemarle Estuarine System, North Carolina

    NASA Astrophysics Data System (ADS)

    Vance, D. J.; Corbett, D. R.; Culver, S. J.

    2002-12-01

    The modern distribution of benthic foraminifera of the Albemarle Estuarine System (AES) has been characterized by studying 50 strategically chosen sites to provide a model for paleoenvironmental interpretations of short sediment cores (15-75 cm). Water bodies studied within the AES include Albemarle Sound, Currituck Sound, Roanoke Sound, Croatan Sound, northern Pamlico Sound, North River, Pasquotank River, Alligator River, as well as Oregon Inlet and the adjacent foreshore and shoreface of the Atlantic Ocean. Sedimentation rates in the study area have been addressed using 210Pb and 137Cs dating methods. Five foraminiferal assemblages are present: an inner estuary biofacies characterized by two dominant genera, Ammobaculites and Ammotium, with moderate percentages of Miliammina fusca and minor percentages of Ammoastuta salsa; an outer estuary biofacies characterized again by Ammobaculites and Ammotium, but with lower percentages of Miliammina fusca; a marsh shoreline biofacies characterized by a mixed assemblage dominated by Ammobaculites and Ammotium with minor to moderate percentages of adjacent marsh foraminifera; a marsh biofacies characterized by varying abundances of Ammoastuta inepta, Arenoparella mexicana, Haplophragmoides wilberti, Jadammina macrescens, Miliammina earlandi, Miliammina fusca, Tiphotrocha comprimata, Trochammina inflata, as well as the genera Ammobaculites and Ammotium; and a marine (normal salinity) biofacies characterized mainly by Elphidium excavatum and minor percentages of other elphidiids. Sedimentation rates were studied from 28 short cores taken along transects in all the major water bodies. Rates were as high as 0.45 cm/yr at the head of Albemarle Sound and as little as 0.05 cm/yr 60 km away in the eastern part of the Albemarle. The embayed tributaries exhibited sedimentation rates on the order of 0.25 cm/yr. Limited information on sedimentation rates was provided by cores in eastern sounds, which had only a few centimeters of recent

  8. Factors affecting the efficiency of carbon monoxide photoproduction in the St. Lawrence estuarine system (Canada).

    PubMed

    Zhang, Yong; Xie, Huixiang; Chen, Guohua

    2006-12-15

    This study examined the effects of water temperature and the origin (terrestrial vs marine) and light history of chromophoric dissolved organic matter (CDOM) on the apparent quantum yields of carbon monoxide (CO) photoproduction for water samples collected along a salinity gradient (salinity range: 0-33) in the St. Lawrence estuarine system (Canada). The solar insolation-weighted mean apparent quantum yield of CO (phico) decreased as much as fourfold with increasing salinity and showed a strong positive correlation with the dissolved organic carbon-specific absorption coefficient at 254 nm. This suggests that terrestrial CDOM is more efficient at photochemically producing CO than is marine algae-derived CDOM and that aromatic moieties are likely involved in this photoprocess. CDOM photobleaching, mainly at the very early stage, dramatically decreased phico (by up to 6.4 times) for low-salinity samples, but photobleaching had little effect on the most marine sample. For a 20 degree C increase in temperature, phico increased by approximately 70% for low-salinity samples and 30-40% for saline samples. This study demonstrates that water temperature, as well as the CDOM's origin and light history, strongly affect the efficiency of CO photoproduction. These factors should be taken into account in modeling the photochemical fluxes of CO and other related CDOM photoproducts on varying spatiotemporal scales.

  9. Particle release transport in Danshuei River estuarine system and adjacent coastal ocean: a modeling assessment.

    PubMed

    Chen, Wei-Bo; Liu, Wen-Cheng; Kimura, Nobuaki; Hsu, Ming-Hsi

    2010-09-01

    A three-dimensional hydrodynamic model was created to study the Danshuei River estuarine system and adjacent coastal ocean in Taiwan. The model was verified using measurements of the time-series water surface elevation, tidal current, and salinity from 1999. We conclude that our model is consistent with these observations. Our particle-tracking model was also used to explore the transport of particles released from the Hsin-Hai Bridge, an area that is heavily polluted. The results suggest that it takes a much longer time for the estuary to be flushed out under low freshwater discharge conditions than with high freshwater discharge. We conclude that the northeast and southwest winds minimally impact particle dispersion in the estuary. The particles fail to settle to the bottom in the absence of density-induced circulation. Our model was also used to simulate the ocean outfall at the Bali. Our experimental results suggest that the tidal current dominates the particle trajectories and influences the transport properties in the absence of a wind stress condition. The particles tend to move northeast or southwest along the coast when northeast or southwest winds prevail. Our data suggest that wind-driven currents and tidal currents play important roles in water movement as linked with ocean outfall in the context of the Danshuei River.

  10. Modelling sensitivities to mixing and advection in a sill-basin estuarine system

    NASA Astrophysics Data System (ADS)

    Soontiens, Nancy; Allen, Susan E.

    2017-04-01

    This study investigates the sensitivity of a high resolution regional ocean model to several choices in mixing and advection. The oceanographic process examined is a deep water renewal event in the Juan de Fuca Strait-Strait of Georgia sill-basin estuarine system located on the west coast of North America. Previous observational work has shown that the timing of the renewal events is linked to the spring/neap tidal cycle, and in turn, is sensitive to the amount of vertical mixing induced by tidal currents interacting with sills and complicated bathymetry. It is found that the model's representation of deep water renewal is relatively insensitive to several mixing choices, including the vertical turbulence closure and direction of lateral mixing. No significant difference in deep or intermediate salinity was found between cases that used k - ɛ versus k - ω closures and isoneutral versus horizontal lateral mixing. Modifications that had a stronger effect included those that involved advection such as modifying the salinity of the open boundary conditions which supply the source waters for the renewal event. The strongest impact came from the removal of the Hollingsworth instability, a kinetic energy sink in the energy-enstrophy discretization of the momentum equations. A marked improvement to the salinity of the deep water renewal suggests that the removal of the Hollingsworth instability will correct a fresh drift in the deep and intermediate waters in an operational version of this model.

  11. Annual cycle of humic substances in a temperate estuarine system affected by agricultural practices

    NASA Astrophysics Data System (ADS)

    Waeles, Matthieu; Riso, Ricardo; Pernet-Coudrier, Benoît; Quentel, François; Durrieu, Gaël; Tissot, Cyril

    2013-04-01

    Although widely studied for their chemical structures and properties (e.g., metal complexation, growth stimulation of planktonic species), humic substances (HS) have been very poorly quantified in fluvial and estuarine waters. In this monthly basis study, we determined HS concentrations (by Adsorptive Square Wave Cathodic Stripping Voltammetry) along the entire river-seawater gradient of the Penzé estuary (NW France), with the aim to characterize the export of these compounds. In this watershed where agricultural activities are predominant, manuring activities were identified as being the main source of dissolved organic carbon (DOC) and HS. HS concentrations varied usually within a narrow range in fluvial waters, i.e., 1.8 ± 0.4 mgC L-1 (150 ± 40 μM), but increased significantly as the first flood of autumn occurred (>4 mgC L-1 in river and upper estuary). At this time, HS accounted for a very high proportion of DOC (>80%). As evidenced by the increasing contribution of HS to DOC, and by the increasing contribution of small colloidal HS species; this autumnal flood increase should be attributed to a greater retention and transformation of organic matter on soils over the hotter, drier, and lighter period preceding the first autumnal flood. In the mixing zone, HS displayed mostly conservative behaviour, although some removals were occasionally observed. Overall, our study suggests that preservation of HS could be relatively important during their transfer across macrotidal temperate estuaries, at least in systems affected by agricultural practices.

  12. Assessment of the climate change impacts on fecal coliform contamination in a tidal estuarine system.

    PubMed

    Liu, Wen-Cheng; Chan, Wen-Ting

    2015-12-01

    Climate change is one of the key factors affecting the future microbiological water quality in rivers and tidal estuaries. A coupled 3D hydrodynamic and fecal coliform transport model was developed and applied to the Danshuei River estuarine system for predicting the influences of climate change on microbiological water quality. The hydrodynamic and fecal coliform model was validated using observational salinity and fecal coliform distributions. According to the analyses of the statistical error, predictions of the salinity and the fecal coliform concentration from the model simulation quantitatively agreed with the observed data. The validated model was then applied to predict the fecal coliform contamination as a result of climate change, including the change of freshwater discharge and the sea level rise. We found that the reduction of freshwater discharge under climate change scenarios resulted in an increase in the fecal coliform concentration. The sea level rise would decrease fecal coliform distributions because both the water level and the water volume increased. A reduction in freshwater discharge has a negative impact on the fecal coliform concentration, whereas a rising sea level has a positive influence on the fecal coliform contamination. An appropriate strategy for the effective microbiological management in tidal estuaries is required to reveal the persistent trends of climate in the future.

  13. Seasonal patterns of alkalinity in the San Francisco Bay estuarine system, California, during 1980

    USGS Publications Warehouse

    Schemel, L.E.

    1984-01-01

    Salinity and alkalinity were measured in the near-surface waters of San Francisco Bay estuarine system at two-week intervals during 1980. Results are presented in figures and as numerical values, and the analytical methods are detailed. The transport of alkalinity to the Bay from the delta during 1980 was 3.8 x 10 to Ohe 10th power equivalents; this estimate is based on the freshwater alkalinity concentrations predicted by the north San Francisco Bay salinity-alkalinity distributions. North San Francisco Bay distributions are primarily the result of conservative mixing of freshwater from the Delta with Pacific Ocean water. Nonlinear distributions are the consequence of alkalinity variations in the freshwater rather than the effects of in-estuary processes or sources. Seasonal inflow of agricultural waste water is a major cause of freshwater alkalinity variations. South San Francisco Bay salinity-alkalinity distributions show the effects of variations in Delta outflow rate, local streams, and municipal waste-water inflows. (USGS)

  14. Phytoplankton productivity and biomass in the Charlotte Harbor estuarine system, Florida

    SciTech Connect

    McPherson, B.F.; Montgomery, R.T.; Emmons, E.E. Environmental Quality Lab., Inc., Port Charlotte, FL )

    1990-10-01

    Phytoplankton carbon-14 productivity at a depth of 50 percent of surface light and chlorophyll-a concentrations were measured every other month from November 1985 through September 1986 at 12 stations in the Charlotte Harbor estuarine system. Maximum productivity and chlorophyll-a concentrations occurred during summer or early autumn near the mouths of tidal rivers. Most of the variability in light-normalized productivity and chlorophyll-a could be attributed to two factors derived from Principal Component Analysis of ambient water-quality characteristics. One factor related to seasonal variability and the other to spatial variability. The seasonal factor incorporated the interaction of temperature and nutrients. The spatial factor incorporated the interaction of salinity, nutrients, and water color that resulted from the mixing of freshwater inflow and seawater. Although freshwater inflow increased the availability of nutrients in low salinity waters, the highly colored freshwater restricted light penetration and phytoplankton productivity. Maximum productivity and biomass occurred where color associated with the freshwater inflow had been diluted by seawater so that light and nutrients were both available. Concentrations of inorganic nitrogen were often ar or below detection limit throughout most of the high salinity waters of the estuary and was probably the most critical nutrient in limiting phytoplankton productivity.

  15. Toward Understanding the Dynamics of Microbial Communities in an Estuarine System

    PubMed Central

    Wang, Yong; Lee, On On; Yang, Jiangke; Chan, Colin; Song, Xingyu; Qian, Pei-Yuan

    2014-01-01

    Community assembly theories such as species sorting theory provide a framework for understanding the structures and dynamics of local communities. The effect of theoretical mechanisms can vary with the scales of observation and effects of specific environmental factors. Based on 16S rRNA gene tag pyrosequencing, different structures and temporal succession patterns were discovered between the surface sediments and bottom water microbial communities in the Pearl River Estuary (PRE). The microbial communities in the surface sediment samples were more diverse than those in the bottom water samples, and several genera were specific for the water or sediment communities. Moreover, water temperature was identified as the main variable driving community dynamics and the microbial communities in the sediment showed a greater temporal change. We speculate that nutrient-based species sorting and bacterial plasticity to the temperature contribute to the variations observed between sediment and water communities in the PRE. This study provides a more comprehensive understanding of the microbial community structures in a highly dynamic estuarine system and sheds light on the applicability of ecological theoretical mechanisms. PMID:24732211

  16. Phytoplankton productivity and biomass in the Charlotte Harbor estuarine system, Florida

    USGS Publications Warehouse

    McPherson, Benjamin F.; Montgomery, Ralph T.; Emmons, Edward E.

    1990-01-01

    Phytoplankton carbon-14 productivity at a depth of 50 percent of surface light and chlorophyll-a concentrations were measured every other month from November 1985 through September 1986 at 12 stations in the Charlotte Harbor estuarine system. Maximum productivity and chlorophyll-a concentrations occurred during summer or early autumn near the months of tidal rivers. Most of the variability in light-normalized productivity and chlorophyll-a could be attributed to two factors derived from Principal Component Analysis of ambient water-quality characteristics. One factor related to seasonal variability and the other to spatial variability. The seasonal factor incorporated the interaction of temperature and nutrients. The spatial factor incorporated the interaction of salinity, nutrients, and water color that resulted from the mixing of freshwater inflow and seawater. Although freshwater inflow increased the availability of nutrients in low salinity (less than 10 %) waters, the highly colored freshwater restricted light penetration and phytoplankton productivity. Maximum productivity and biomass occurred where color associated with the freshwater inflow had been diluted by seawater so that light and nutrients were both available. Concentrations of inorganic nitrogen were often at or below detection limit throughout most of the high salinity (greater than 20 %) waters of the estuary and was probably the most critical nutrient in limiting phytoplankton productivity.

  17. Simulation of the Great Bay Estuarine System: Tides with tidal flats wetting and drying

    NASA Astrophysics Data System (ADS)

    Ertürk, Ş. N.; Bilgili, A.; Swift, M. R.; Brown, W. S.; Çelikkol, B.; Ip, J. T. C.; Lynch, D. R.

    2002-05-01

    Realistic lunar tides of the Great Bay Estuarine System have been simulated using a fixed boundary finite element numerical model as described by Ip et al. [1998]. It is a two-dimensional, nonlinear, time-stepping model with a groundwater component coupled to a kinematic force balance to facilitate the realistic drainage and filling of elements during ebb and flood, respectively. The numerical model reproduces the observed M2 tides as described by Swift and Brown [1983], and it successfully captures qualitatively correct residual currents and transports, realistic mass-conserving flooding and dewatering of the tidal flats, and current asymmetry between flood and ebb. The simulation results were sensitive to local bathymetry and the implemented friction law. The accuracy of the model is demonstrated by comparison with the 1975 Great Bay study [Swift and Brown, 1983] in terms of tidal elevations at 14 tidal stations and 4 cross-sectionally averaged current measurements in the estuary. Quantitatively, the model results show good agreement with observations, displaying correlation coefficients of >=0.96 in surface elevation and >=0.95 in averaged current, with average RMS errors of 0.12 m and 0.26 m s-1, respectively. In addition, tidal flat hydrodynamics, characteristic distributions of residual current, sediment bed load transport, and influence of topography on the overall circulation in the region are also discussed.

  18. Evaluation of anthropogenic contamination using sterol markers in a tropical estuarine system of northeast Brazil.

    PubMed

    Frena, Morgana; Souza, Michel R R; Damasceno, Flaviana C; Madureira, Luiz A S; Alexandre, Marcelo R

    2016-08-15

    The São Francisco River estuarine system, located in the Northeast coast of Brazil, has great economic, tourist and social importance. Its waters are used for activities such as agriculture, aquaculture, navigation and fishery, which supplies the surrounding communities. In this study, sterols markers were determined in twenty-eight sediment samples from São Francisco River estuary by gas chromatography - mass spectrometry (GC-MS). Sterol analysis was useful to distinguish between anthropogenic and biogenic organic matter (OM) sources in the studied area. Six sterols were quantified, suggesting different sources. Concentrations of fecal sterol (coprostanol) were lower than 500ngg(-1), suggesting no indicative of severe sewage contamination.However, two stations showed concentrations around 100ngg(-1) and the values for the coprostanol/(coprostanol+cholestanol) and coprostanol/cholesterol ratios indicates sewage contamination. The results in this study may be considered as baseline concentrations to be used as future reference for monitoring programs to prevent anthropogenic impacts. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Evidence for millennial-scale climatic events in the sedimentary infilling of a macrotidal estuarine system, the Seine estuary (NW France)

    NASA Astrophysics Data System (ADS)

    Sorrel, Philippe; Tessier, Bernadette; Demory, François; Delsinne, Nicolas; Mouazé, Dominique

    2009-03-01

    High-resolution sedimentological and rock magnetic analyses from sediment cores collected in the Seine estuary record changes in coastal sedimentary dynamics linked to climatic variations during the late Holocene. Using AMS 14C and paleomagnetic data we present a first attempt in developing a reliable age model on macrotidal estuarine archives, with a decadal resolution. Correlations between sedimentary successions from the outer Seine estuary document the main sedimentary infilling phases of the system during the last 3000 years. Between 3000 and 1150 cal. BP sedimentary patterns reveal that sequence deposition and preservation are predominantly controlled by marine and tidal hydrodynamics while severe storm events are recorded at ca. 2700 and 1250 cal. BP in the outermost estuary. Conversely, the Medieval Warm Period (MWP; 900-1200 AD) is characterized by a drastic waning of the influence of marine hydrodynamics on sediment preservation. Pronounced episodes of Seine river floods indicate a much stronger impact of continental inputs on sedimentary patterns during this period. The onset of the Little Ice Age marks a diminishing influence of continental inputs while tidal and open marine hydrodynamics again exerted a primary control on the sedimentary evolution of the system during 1200-2003 AD. Coastal sedimentary dynamics as preserved within sedimentary successions appear to have been largely influenced by changes in storminess during the last 3000 years. We have matched the preservation of MWP Seine river floods, as revealed by sedimentological and rock magnetic proxy data, to a prolonged interval of weakened storminess in Normandy permitting the preservation of estuarine flood deposits within a context of reduced coastal erosion in northern Europe. The preservation of sedimentary successions in the Seine estuary is therefore maximal when climate conditions resembled those of the preferred low phase of the NAO on multidecadal timescales such as during 800-1200 AD

  20. Water Quality Gradients across Albemarle-Pamlico Estuarine System: Seasonal Variations and Model Applications

    NASA Astrophysics Data System (ADS)

    Lin, J.; Xie, L.; Pietrafesa, L.

    2004-12-01

    The seasonal variations of water quality parameters as nitrite plus nitrate (NO23), total phosphate (PO4), Chlorophyll a and dissolved oxygen (DO) are analyzed across the Croatan-Roanoke-Albemarle-Pamlico-Core Sounds Estuarine System (CAPES). Overall, several patterns are observed: The Chowan-Roanoke-Albemarle system is generally phosphorous limiting for phytoplankton growth, while both the Tar-Pamlico and the Neuse Rivers are generally nitrogen limiting. The largest PO4 gradients exist in the upper estuary of the Albemarle Sound and the largest NO23 gradients exist in the upper estuary of the Neuse and the Tar-Pamlico Rivers. Dissolved oxygen appears to have the strongest seasonal signal among the water quality variables with highest DO values observed during winter (within the CAPES and in the nearshore area) or spring (in the continental shelf and deeper ocean) and lowest during summer. Chlorophyll a concentrations are highest during spring (within the CAPES) or winter (offshore). In contrast, the NO23 and PO4 concentrations in both the Tar-Pamlico and Neuse River Estuaries are usually higher during the second half of the year. The time differences of the peak nutrient and chlorophyll a concentrations suggest that highest algal growth rate (and hence nutrient uptake rate) occur during spring while the consumed nutrients are released to the water column through a nutrient recycling method later in the year. A coupled three-dimensional hydrodynamic water quality model is then applied to the entire system. The general model set-up and parameter derivation of the model is presented in the paper. The basic observed water quality characteristics such as the nutrient limiting pattern and the spatial gradients across the system are reproduced in the model. The model results also suggest that nutrient fluxes, generated from the diagenesis of deposited organic matters and released from the sediment bed may be an important mechanism for nutrient recycling in the region.

  1. Distribution, sources and biogeochemistry of organic matter in a mangrove dominated estuarine system (Indian Sundarbans) during the pre-monsoon

    NASA Astrophysics Data System (ADS)

    Ray, R.; Rixen, T.; Baum, A.; Malik, A.; Gleixner, G.; Jana, T. K.

    2015-12-01

    The sources and distribution of dissolved organic carbon (DOC), particulate organic carbon (POC) and dissolved inorganic carbon (DIC) in the Indian Sundarbans mangrove and Hooghly estuarine system were examined during the pre-monsoon (summer) 2014. DOC is the dominant form of organic matter (OM) in the studied estuarine waters and represents a mixture of mangrove and riverine sources. Microbial degradation of land derived OM results in a high pCO2 in the Hooghly estuarine waters while enrichment in δ13C-DIC ascribes to CO2 uptake by phytoplankton in the Sundarbans water. Higher δ15N in the particulate organic nitrogen (PON) of the mangrove and marine zone could be associated with enhanced phytoplankton production sustained by nitrate from mangrove derived OM decomposition and/or nitrate imported from the Bay of Bengal. Low organic carbon contents and elemental ratios (TN/TOC) indicate an intense mineralization and transformation of OM in the sediments, resulting insignificantly different OM compositions compared to those of the three major sources: land derived OM, mangrove leaf litter (Avicennia marina) and in situ phytoplankton production.

  2. The structure of the benthic macrofaunal assemblages and sediments characteristics of the Paraguaçu estuarine system, NE, Brazil

    NASA Astrophysics Data System (ADS)

    Barros, Francisco; Hatje, Vanessa; Figueiredo, Maria Betânia; Magalhães, Wagner Ferreira; Dórea, Haroldo Silveira; Emídio, Elissandro Soares

    2008-07-01

    The structure of the benthic macrofaunal assemblages of the estuarine portion of Paraguaçu River, NE, Brazil, and its relationship with surface sediment characteristics (trace metals, PAHs, nutrients and grain size) and physical variables were investigated at ten stations on two contrasting occasions, summer (dry season) and winter (rainy season). A total of 1258 individuals (632 in winter and 626 in summer) and 62 taxa representing polychaetes, crustaceans, bivalves, echinoderms, bryozoans, sponges, cnidarians and cephalochordates were collected. Benthic assemblages in the upper estuary were unlike those in the lower estuary and a clear substitution of benthic taxa along the estuary was observed. Macrofaunal invertebrates in the low salinity region, composed of coarse sediments, were dominated by tellinids, venerids (bivalves), cirolanids (isopods), cyclopoids (copepods), and nereidids (polychaetes). While the high salinity region, composed of fine sediments, were dominated by nuculids (bivalves), cirratulids (polychaetes), and by amphiurids (ophiuroids). The Paraguaçu estuarine system is not severely affected by anthropogenic activities. In the great majority of the study sites, concentrations of trace metals and PAHs in the sediments were near background values. Nutrients values were also low. We formulated new models of taxon distribution and suggested detailed studies on the effects of salinity variation and studies using functional approaches to better understand the processes causing the spatial patterns in tropical estuarine benthic assemblages.

  3. Water use patterns of estuarine vegetation in a tidal creek system.

    PubMed

    Wei, Lili; Lockington, David A; Poh, Seng-Chee; Gasparon, Massimo; Lovelock, Catherine E

    2013-06-01

    Water availability is a key determinant of the zonation patterns in estuarine vegetation, but water availability and the use of different water sources over space and time are not well understood. We have determined the seasonal water use patterns of riparian vegetation over an estuarine ecotone. Our aim was to investigate how the water use patterns of estuarine vegetation respond to variations in the availability of tidal creek water and rain-derived freshwater. The levels of natural stable isotopes of oxygen and hydrogen were assessed in the stem of the mangrove Avicennia marina (tall and scrub growth forms), Casuarina glauca and Melaleuca quinquenervia that were distributed along transects from river/creek-front towards inland habitats. The isotopic composition of plant tissues and the potential water sources were assessed in both the wet season, when freshwater from rainfall is present, and the dry season, when mangrove trees are expected to be more dependent on tidal water, and when Casuarina and Melaleuca are expected to be dependent on groundwater. Our results indicate that rainwater during the wet season contributes significantly to estuarine vegetation, even to creek-side mangroves which are inundated by tidal creek water daily, and that estuarine vegetation depends primarily on freshwater throughout the year. In contrast, high intertidal scrub mangroves were found to use the greatest proportion of tidal creek water, supplemented by groundwater in the dry season. Contrary to prediction, inland trees C. glauca and M. quinquenervia were found also to rely predominantly on rainwater--even in the dry season. The results of this study reveal a high level of complexity in vegetation water use in estuarine settings.

  4. An assessment of mercury in estuarine sediment and tissue in Southern New Jersey using public domain data

    USGS Publications Warehouse

    Ng, Kara; Szabo, Zoltan; Reilly, Pamela A.; Barringer, Julia; Smalling, Kelly L.

    2016-01-01

    Mercury (Hg) is considered a contaminant of global concern for coastal environments due to its toxicity, widespread occurrence in sediment, and bioaccumulation in tissue. Coastal New Jersey, USA, is characterized by shallow bays and wetlands that provide critical habitat for wildlife but share space with expanding urban landscapes. This study was designed as an assessment of the magnitude and distribution of Hg in coastal New Jersey sediments and critical species using publicly available data to highlight potential data gaps. Mercury concentrations in estuary sediments can exceed 2 μg/g and correlate with concentrations of other metals. Based on existing data, the concentrations of Hg in mussels in southern New Jersey are comparable to those observed in other urbanized Atlantic Coast estuaries. Lack of methylmercury data for sediments, other media, and tissues are data gaps needing to be filled for a clearer understanding of the impacts of Hg inputs to the ecosystem.

  5. An assessment of mercury in estuarine sediment and tissue in Southern New Jersey using public domain data.

    PubMed

    Ng, Kara; Szabo, Zoltan; Reilly, Pamela A; Barringer, Julia L; Smalling, Kelly L

    2016-06-15

    Mercury (Hg) is considered a contaminant of global concern for coastal environments due to its toxicity, widespread occurrence in sediment, and bioaccumulation in tissue. Coastal New Jersey, USA, is characterized by shallow bays and wetlands that provide critical habitat for wildlife but share space with expanding urban landscapes. This study was designed as an assessment of the magnitude and distribution of Hg in coastal New Jersey sediments and critical species using publicly available data to highlight potential data gaps. Mercury concentrations in estuary sediments can exceed 2μg/g and correlate with concentrations of other metals. Based on existing data, the concentrations of Hg in mussels in southern New Jersey are comparable to those observed in other urbanized Atlantic Coast estuaries. Lack of methylmercury data for sediments, other media, and tissues are data gaps needing to be filled for a clearer understanding of the impacts of Hg inputs to the ecosystem.

  6. Improving the Representation of Estuarine and Shelf Processes in Earth System Models

    NASA Astrophysics Data System (ADS)

    Sun, Q.; Whitney, M. M.; Bryan, F.; Tseng, Y. H.; MacCready, P.

    2016-02-01

    The fluvial discharges of freshwater have much larger impacts on oceanic dynamics than would be guessed based on their total volume flux alone. Model studies have shown that stronger stratification due to increasing fluvial discharge could substantially slow and even shut down meridional overturning in the North Atlantic (Rahmstorf, 1995; Marzeion, et. al. 2007). Indeed, not only the amount of riverine freshwater, but also the way it is injected into ocean affects ocean stratification (e.g Hordoir, et. al. 2008). In most earth system models, the fluvial discharge is imported into the ocean model with zero salinity. This method omits important natural physical processes in estuaries and on continental shelves that pre-mix the riverine water with oceanic water and can change the location and timing of freshwater delivery to the ocean. However, computational time constraints limit global ocean models to coarse horizontal resolution (e.g. 1 degree latitude), so the estuarine and shelf processes cannot be resolved. In the current study, two adjacent box models are employed to represent the unresolved mixing processes in the estuary and shelf. The Estuary Box Model (EBM) with two-layer structure represents the mixing processes driven by tides and bottom friction in the estuaries and creates an exchange flow that introduces saltier lower-layer water into the fresher surface layer. The adjacent Shelf Plume Box Model (SPBM) treats the released water mass from EBM as a collection of plume boxes that can propagate along the coast and undergo shear-driven entrainment during light winds or rapidly mix and advected offshore during upwelling favorable winds. The EBM and SPBM are compared to observations and regional simulation data for the Columbia River. The EBM is globally implemented within the ocean model of the Community Earth System Model (CESM). The performance of SPBM is tested in CESM at Columbia River. Comparisons of runs with and without the box models show pronounce

  7. Predicting the Spatial Distribution of Organic Contaminants in an Estuarine System using a Random Forest Approach

    EPA Science Inventory

    Modeling the magnitude and distribution of estuarine sediment contamination by pollutants of historic (e.g. PCB) and emerging concern (e.g., personal care products, PCP) is often limited by incomplete site knowledge and inadequate sediment contamination sampling. We tested a mode...

  8. Using a Laboratory Simulator in the Teaching and Study of Chemical Processes in Estuarine Systems

    ERIC Educational Resources Information Center

    Garcia-Luque, E.; Ortega, T.; Forja, J. M.; Gomez-Parra, A.

    2004-01-01

    The teaching of Chemical Oceanography in the Faculty of Marine and Environmental Sciences of the University of Cadiz (Spain) has been improved since 1994 by the employment of a device for the laboratory simulation of estuarine mixing processes and the characterisation of the chemical behaviour of many substances that pass through an estuary. The…

  9. Using a Laboratory Simulator in the Teaching and Study of Chemical Processes in Estuarine Systems

    ERIC Educational Resources Information Center

    Garcia-Luque, E.; Ortega, T.; Forja, J. M.; Gomez-Parra, A.

    2004-01-01

    The teaching of Chemical Oceanography in the Faculty of Marine and Environmental Sciences of the University of Cadiz (Spain) has been improved since 1994 by the employment of a device for the laboratory simulation of estuarine mixing processes and the characterisation of the chemical behaviour of many substances that pass through an estuary. The…

  10. Predicting the Spatial Distribution of Organic Contaminants in an Estuarine System using a Random Forest Approach

    EPA Science Inventory

    Modeling the magnitude and distribution of estuarine sediment contamination by pollutants of historic (e.g. PCB) and emerging concern (e.g., personal care products, PCP) is often limited by incomplete site knowledge and inadequate sediment contamination sampling. We tested a mode...

  11. Overview of integrative tools and methods in assessing ecological integrity in estuarine and coastal systems worldwide.

    PubMed

    Borja, Angel; Bricker, Suzanne B; Dauer, Daniel M; Demetriades, Nicolette T; Ferreira, João G; Forbes, Anthony T; Hutchings, Pat; Jia, Xiaoping; Kenchington, Richard; Carlos Marques, João; Zhu, Changbo

    2008-09-01

    In recent years, several sets of legislation worldwide (Oceans Act in USA, Australia or Canada; Water Framework Directive or Marine Strategy in Europe, National Water Act in South Africa, etc.) have been developed in order to address ecological quality or integrity, within estuarine and coastal systems. Most such legislation seeks to define quality in an integrative way, by using several biological elements, together with physico-chemical and pollution elements. Such an approach allows assessment of ecological status at the ecosystem level ('ecosystem approach' or 'holistic approach' methodologies), rather than at species level (e.g. mussel biomonitoring or Mussel Watch) or just at chemical level (i.e. quality objectives) alone. Increasing attention has been paid to the development of tools for different physico-chemical or biological (phytoplankton, zooplankton, benthos, algae, phanerogams, fishes) elements of the ecosystems. However, few methodologies integrate all the elements into a single evaluation of a water body. The need for such integrative tools to assess ecosystem quality is very important, both from a scientific and stakeholder point of view. Politicians and managers need information from simple and pragmatic, but scientifically sound methodologies, in order to show to society the evolution of a zone (estuary, coastal area, etc.), taking into account human pressures or recovery processes. These approaches include: (i) multidisciplinarity, inherent in the teams involved in their implementation; (ii) integration of biotic and abiotic factors; (iii) accurate and validated methods in determining ecological integrity; and (iv) adequate indicators to follow the evolution of the monitored ecosystems. While some countries increasingly use the establishment of marine parks to conserve marine biodiversity and ecological integrity, there is awareness (e.g. in Australia) that conservation and management of marine ecosystems cannot be restricted to Marine Protected

  12. Application of factor and cluster analysis for characterization of river and estuarine water systems A case study: Mahanadi River (India)

    NASA Astrophysics Data System (ADS)

    Panda, Unmesh Chandra; Sundaray, Sanjay Kumar; Rath, Prasant; Nayak, Binod Bihari; Bhatta, Dinabandhu

    2006-12-01

    SummaryIn order to establish the natural and anthropogenic processes and factors responsible for enrichment of hydrological features, R-mode factor analysis and cluster analysis are applied for three different sets of data i.e. total, fresh and saline influenced stations in Mahanadi river systems. The results of R-mode factor analyses reveal that anthropogenic contribution of nutrients is responsible for lowering DO and pH level of water, though its intensity is different in fresh and saline systems as well as in different seasons. The different magnitude of biochemical oxygen demand (BOD) loading with respect to total nitrogen and phosphorus demonstrated the intensity of organic pollution in different water systems. The removal of silicate in saline system is clearly visible through factor analysis and different mode of association of TSS is reflected seasonally. The relationships among the stations are highlighted by cluster analysis represented in dendrograms to categorize different level of contamination. Considering the diversity of the mechanisms played in estuarine and river water systems, it is felt that statistically their data should be treated separately on the basis of influence of salinity. It is confirmed from our results that the relative importance water quality characteristics varies with specific system. This study presents necessity and usefulness of multivariate statistical techniques for evaluation and monitoring network for effective management of fresh and estuarine systems.

  13. The New Southern FIA Data Compilation System

    Treesearch

    V. Clark Baldwin; Larry Royer

    2001-01-01

    In general, the major national Forest Inventory and Analysis annual inventory emphasis has been on data-base design and not on data processing and calculation of various new attributes. Two key programming techniques required for efficient data processing are indexing and modularization. The Southern Research Station Compilation System utilizes modular and indexing...

  14. Northeast Coastal Ocean Forecast System (NECOFS): A Multi-scale Global-Regional-Estuarine FVCOM Model

    NASA Astrophysics Data System (ADS)

    Beardsley, R. C.; Chen, C.

    2014-12-01

    The Northeast Coastal Ocean Forecast System (NECOFS) is a global-regional-estuarine integrated atmosphere/surface wave/ocean forecast model system designed for the northeast US coastal region covering a computational domain from central New Jersey to the eastern end of the Scotian Shelf. The present system includes 1) the mesoscale meteorological model WRF (Weather Research and Forecasting); 2) the regional-domain FVCOM covering the Gulf of Maine/Georges Bank/New England Shelf region (GOM-FVCOM); 3) the unstructured-grid surface wave model (FVCOM-SWAVE) modified from SWAN with the same domain as GOM-FVCOM; 3) the Mass coastal FVCOM with inclusion of inlets, estuaries and intertidal wetlands; and 4) three subdomain wave-current coupled inundation FVCOM systems in Scituate, MA, Hampton River, NH and Mass Bay, MA. GOM-FVCOM grid features unstructured triangular meshes with horizontal resolution of ~ 0.3-25 km and a hybrid terrain-following vertical coordinate with a total of 45 layers. The Mass coastal FVCOM grid is configured with triangular meshes with horizontal resolution up to ~10 m, and 10 layers in the vertical. Scituate, Hampton River and Mass Bay inundation model grids include both water and land with horizontal resolution up to ~5-10 m and 10 vertical layers. GOM-FVCOM is driven by surface forcing from WRF model output configured for the region (with 9-km resolution), the COARE3 bulk air-sea flux algorithm, local river discharges, and tidal forcing constructed by eight constituents and subtidal forcing on the boundary nested to the Global-FVCOM. SWAVE is driven by the same WRF wind field with wave forcing at the boundary nested to Wave Watch III configured for the northwestern Atlantic region. The Mass coastal FVCOM and three inundation models are connected with GOM-FVCOM through one-way nesting in the common boundary zones. The Mass coastal FVCOM is driven by the same surface forcing as GOM-FVCOM. The nesting boundary conditions for the inundation models

  15. Chesapeake Bay nitrogen fluxes derived from a land-estuarine ocean biogeochemical modeling system: Model description, evaluation, and nitrogen budgets.

    PubMed

    Feng, Yang; Friedrichs, Marjorie A M; Wilkin, John; Tian, Hanqin; Yang, Qichun; Hofmann, Eileen E; Wiggert, Jerry D; Hood, Raleigh R

    2015-08-01

    The Chesapeake Bay plays an important role in transforming riverine nutrients before they are exported to the adjacent continental shelf. Although the mean nitrogen budget of the Chesapeake Bay has been previously estimated from observations, uncertainties associated with interannually varying hydrological conditions remain. In this study, a land-estuarine-ocean biogeochemical modeling system is developed to quantify Chesapeake riverine nitrogen inputs, within-estuary nitrogen transformation processes and the ultimate export of nitrogen to the coastal ocean. Model skill was evaluated using extensive in situ and satellite-derived data, and a simulation using environmental conditions for 2001-2005 was conducted to quantify the Chesapeake Bay nitrogen budget. The 5 year simulation was characterized by large riverine inputs of nitrogen (154 × 10(9) g N yr(-1)) split roughly 60:40 between inorganic:organic components. Much of this was denitrified (34 × 10(9) g N yr(-1)) and buried (46 × 10(9) g N yr(-1)) within the estuarine system. A positive net annual ecosystem production for the bay further contributed to a large advective export of organic nitrogen to the shelf (91 × 10(9) g N yr(-1)) and negligible inorganic nitrogen export. Interannual variability was strong, particularly for the riverine nitrogen fluxes. In years with higher than average riverine nitrogen inputs, most of this excess nitrogen (50-60%) was exported from the bay as organic nitrogen, with the remaining split between burial, denitrification, and inorganic export to the coastal ocean. In comparison to previous simulations using generic shelf biogeochemical model formulations inside the estuary, the estuarine biogeochemical model described here produced more realistic and significantly greater exports of organic nitrogen and lower exports of inorganic nitrogen to the shelf.

  16. Catchment controls and human disturbances on the geomorphology of small Mediterranean estuarine systems

    NASA Astrophysics Data System (ADS)

    Estrany, Joan; Grimalt, Miquel

    2014-10-01

    Geographic signatures are physical and human-induced characteristics or processes that identify comparable or unique features of estuaries along latitudinal gradients. In Mediterranean areas, the microtidal regime and the strong seasonal and inter-annual contrasts cause an alternation between relatively high runoff and arid conditions. Furthermore, the long history of human settlement also increases the complexity in the study of these estuarine systems. This study investigates these signatures of the estuaries located within the Mallorcan eastern coast, which are geomorphologically homogeneous because of a similar bedrock geology and Holocene history. A multi-method approach focused on the integration of geomorphometry, hydraulics, historical sources and statistics was used. We explore the role played by catchment morphometric parameters, severe flash flood events and human disturbances in controlling the geomorphology of 10 beach-barrier enclosed, fluvial incised lagoons. Most of the lagoons discharge into 'calas', ranging in size from 1345 to 17,537 m2 and their related catchments are representative of the Mediterranean hydrological systems. Multiple regression models illustrate that the size, slope and drainage network development of the catchments explain the variance in length (r2 = 0.67), volume (r2 = 0.49), area (r2 = 0.64), circularity (r2 = 0.72) and average width (r2 = 0.81) of the lagoons. Depending on these catchment morphometric variables, the shape of the lagoons is also determined by the occurrence of catastrophic flash floods, which cause scouring and dredging, whereas the ordinary flood events and sea storms promote refilling and sedimentation. A historical analysis since 1850 documented 18 flood events, 5 of which were catastrophic with destructive effects along the catchments and large morphological changes in coastal lagoons. High intensity rainfall (up to 200 mm in 2 h), the geomorphometry of the catchments and the massive construction of

  17. Sedimentary environments within a glaciated estuarine-inner shelf system: Boston Harbor and Massachusetts Bay

    USGS Publications Warehouse

    Knebel, H. J.

    1993-01-01

    and both geologic and oceanographic processes. The estuarine part of the system is an effective trap for fine-grained detritus because of its protected nature, low wave climate, and large supply of sediments. The open shelf, however, is largely mantled by winnowed and sorted sediments as a result of erosion during past sea-level fluctuations, sediment resuspension and transport by modern waves and currents, and a spatially variable supply of fine-grained sediments.

  18. Inferring nutrient loading of estuarine systems by remote sensing of aquatic vegetation

    NASA Technical Reports Server (NTRS)

    Anderson, R. R.

    1978-01-01

    THe use of remote sensing to record algal and vascular aquatic plant growths in estuarine waters is discussed. A technique is proposed that uses a combination of data to hierarchically classify watersheds with regard to severity of potential pollution. Specific nonpoint sources of nutrients in tributaries of the watershed are identified with lower altitude photography of vegetation and selected ground sampling. It is concluded that excessive growths of some aquatic plants may be related to nutrient pollution.

  19. Inferring nutrient loading of estuarine systems by remote sensing of aquatic vegetation

    NASA Technical Reports Server (NTRS)

    Anderson, R. R.

    1978-01-01

    THe use of remote sensing to record algal and vascular aquatic plant growths in estuarine waters is discussed. A technique is proposed that uses a combination of data to hierarchically classify watersheds with regard to severity of potential pollution. Specific nonpoint sources of nutrients in tributaries of the watershed are identified with lower altitude photography of vegetation and selected ground sampling. It is concluded that excessive growths of some aquatic plants may be related to nutrient pollution.

  20. Photobleaching of dissolved organic material from a tidal marsh-estuarine system of the Chesapeake Bay.

    PubMed

    Tzortziou, Maria; Osburn, Christopher L; Neale, Patrick J

    2007-01-01

    Wetlands and tidal marshes in the Rhode River estuary of the Chesapeake Bay act as important sources of dissolved organic carbon and strongly absorbing dissolved organic matter (DOM) for adjacent estuarine waters. The effects of solar exposure on the photochemical degradation of colored DOM (CDOM) were examined for material derived from different sources (estuarine and freshwater parts of the Rhode River, sub-watershed stream, marshes) in this estuarine ecosystem. Consistent with changes in fluorescence emission, absorption loss upon exposure to different portions of the solar spectrum (i.e. different long-pass cut-off filters) occurred across the entire spectrum but the wavelength of maximum photobleaching decreased as the cut-off wavelength of the filter decreased. Our results illustrate that solar exposure can cause either an increase or a decrease in the CDOM absorption spectral slope, S(CDOM), depending on the spectral quality of irradiation and, thus, on the parameters (e.g. atmospheric composition, concentration of UV-absorbing water constituents) that affect the spectral characteristics of the light to which CDOM is exposed. We derived a simple spectral model for describing the effects of solar exposure on CDOM optical quality. The model accurately, and consistently, predicted the observed dependence of CDOM photobleaching on the spectral quality of solar exposure.

  1. Juvenile winter flounder (Pseudopleuronectes americanus) and summer flounder (Paralichthys dentatus) utilization of Southern New England nurseries: Comparisons among estuarine, tidal river, and coastal lagoon shallow-water habitats.

    PubMed

    Taylor, David L; McNamee, Jason; Lake, John; Gervasi, Carissa L; Palance, Danial G

    2016-09-01

    This study evaluated the relative importance of the N arragansett Bay estuary (RI and MA, USA), and associated tidal rivers and coastal lagoons, as nurseries for juvenile winter flounder, Pseudopleuronectes americanus, and summer flounder, Paralichthys dentatus. Winter flounder (WF) and summer flounder (SF) abundance and growth were measured from May to October (2009-2013) and served as indicators for the use and quality of shallow-water habitats (water depth < 1.5-3.0 m). These bioindicators were then analyzed with respect to physiochemical conditions to determine the mechanisms underlying intra-specific habitat selection. WF and SF abundances were greatest in late May and June (maximum monthly mean = 4.9 and 0.55 flounder/m(2) for WF and SF, respectively), and were significantly higher in the tidal rivers relative to the bay and lagoons. Habitat-related patterns in WF and SF abundance were primarily governed by their preferences for oligohaline (0.1-5 ppt) and mesohaline (6-18 ppt) waters, but also their respective avoidance of hypoxic conditions (< 4 mg DO/L) and warm water temperatures (> 25 °C). Flounder habitat usage was also positively related to sediment organic content, which may be due to these substrates having sufficiently high prey densities. WF growth rates (mean = 0.25 ± 0.14 mm/d) were negatively correlated with the abundance of conspecifics, whereas SF growth (mean = 1.39 ± 0.46 mm/d) was positively related to temperature and salinity. Also, contrary to expectations, flounder occupied habitats that offered no ostensible advantage in intra-specific growth rates. WF and SF exposed to low salinities in certain rivers likely experienced increased osmoregulatory costs, thereby reducing energy for somatic growth. Low-salinity habitats, however, may benefit flounder by providing refugia from predation or reduced competition with other estuarine fishes and macro-invertebrates. Examining WF and SF abundance and growth across each species' broader

  2. Juvenile winter flounder (Pseudopleuronectes americanus) and summer flounder (Paralichthys dentatus) utilization of Southern New England nurseries: Comparisons among estuarine, tidal river, and coastal lagoon shallow-water habitats

    PubMed Central

    Taylor, David L.; McNamee, Jason; Lake, John; Gervasi, Carissa L.; Palance, Danial G.

    2016-01-01

    This study evaluated the relative importance of the N arragansett Bay estuary (RI and MA, USA), and associated tidal rivers and coastal lagoons, as nurseries for juvenile winter flounder, Pseudopleuronectes americanus, and summer flounder, Paralichthys dentatus. Winter flounder (WF) and summer flounder (SF) abundance and growth were measured from May to October (2009–2013) and served as indicators for the use and quality of shallow-water habitats (water depth < 1.5–3.0 m). These bioindicators were then analyzed with respect to physiochemical conditions to determine the mechanisms underlying intra-specific habitat selection. WF and SF abundances were greatest in late May and June (maximum monthly mean = 4.9 and 0.55 flounder/m2 for WF and SF, respectively), and were significantly higher in the tidal rivers relative to the bay and lagoons. Habitat-related patterns in WF and SF abundance were primarily governed by their preferences for oligohaline (0.1–5 ppt) and mesohaline (6–18 ppt) waters, but also their respective avoidance of hypoxic conditions (< 4 mg DO/L) and warm water temperatures (> 25 °C). Flounder habitat usage was also positively related to sediment organic content, which may be due to these substrates having sufficiently high prey densities. WF growth rates (mean = 0.25 ± 0.14 mm/d) were negatively correlated with the abundance of conspecifics, whereas SF growth (mean = 1.39 ± 0.46 mm/d) was positively related to temperature and salinity. Also, contrary to expectations, flounder occupied habitats that offered no ostensible advantage in intra-specific growth rates. WF and SF exposed to low salinities in certain rivers likely experienced increased osmoregulatory costs, thereby reducing energy for somatic growth. Low-salinity habitats, however, may benefit flounder by providing refugia from predation or reduced competition with other estuarine fishes and macro-invertebrates. Examining WF and SF abundance and growth across each species’ broader

  3. Trends in nitrogen isotope ratios of juvenile winter flounder reflect changing nitrogen inputs to Rhode Island, USA estuarine systems.

    PubMed

    Pruell, Richard J; Taplin, Bryan K; Miller, Kenneth M

    2017-05-15

    Nitrogen isotope ratios (δ(15)N) in juvenile winter flounder, Pseudopleuronectes americanus, were used to examine changes in nitrogen inputs to several Rhode Island, USA estuarine systems. Fish were collected over two three-year periods with a ten-year interval between sampling periods (2002-2004 and 2012-2014). During that interval numerous changes to nutrient management practices were initiated in the watersheds of these estuarine systems including the upgrade of several major wastewater treatment facilities that discharge to Narragansett Bay, which significantly reduced nitrogen inputs. Following these reductions, the δ(15)N values of flounder in several of the systems decreased as expected; however, isotope ratios in fish from upper Narragansett Bay significantly increased. We believe that low δ(15)N values measured in 2002-2004 were related to concentration-dependent fractionation at this location. Increased δ(15)N values measured between 2012 and 2014 may indicate reduced fractionation or that changes in wastewater treatment processes altered the nitrogen isotopic ratios of the effluents. Published by Elsevier Ltd.

  4. Using recent hurricanes and associated event layers to evaluate regional storm impacts on estuarine-wetland systems

    NASA Astrophysics Data System (ADS)

    Smith, C. G.; Marot, M. E.; Osterman, L. E.; Adams, C. S.; Haller, C.; Jones, M.

    2016-12-01

    Tropical cyclones are a major driver of change in coastal and estuarine environments. Heightened waves and sea level associated with tropical cyclones act to erode sediment from one environment and redistribute it to adjacent environments. The fate and transport of this redistributed material is of great importance to the long-term sediment budget, which in turns affects the vulnerability of these coastal systems. The spatial variance in both storm impacts and sediment redistribution is large. At the regional-scale, difference in storm impacts can often be attributed to natural variability in geologic parameters (sediment availability/erodibility), coastal geomorphology (including fetch, shoreline tortuosity, back-barrier versus estuarine shoreline, etc.), storm characteristics (intensity, duration, track/approach), and ecology (vegetation type, gradient, density). To assess storm characteristics and coastal geomorphology on a regional-scale, cores were collected from seven Juncus marshes located in coastal regions of Alabama and Mississippi (i.e., Mobile Bay, Bon Secour Bay, Mississippi Sound, and Grand Bay) expected to have been impacted by Hurricane Frederic (1979). All cores were sectioned and processed for water content, organic matter (loss-on-ignition), and select cores analyzed for foraminiferal assemblages, stable isotopes and bulk metals to aid in the identification of storm events. Excess lead-210 and cesium-137 were used to develop chronologies for the cores and evaluate mass accumulation rates and sedimentation rates. Temporal variations in accumulation rates of inorganic and organic sediments were compared with shoreline and areal change rates derived from historic aerial imagery to evaluate potential changes in sediment exchange prior to, during, and following the storm. A combined geospatial and geologic approach will improve our understanding of coastal change in estuarine marsh environments, as well help refine the influence of storms on regional

  5. Simulation of tidal-flow, circulation, and flushing of the Charlotte Harbor Estuarine System, Florida

    USGS Publications Warehouse

    Goodwin, C.R.

    1996-01-01

    A two-dimensional circulation and constituent- transport model, SIMSYS2D, was used to simulate tidal-flow, circulation, and flushing characteristics in Charlotte Harbor. The model was calibrated and verified against field observations of stage,discharge, and velocity. Standard errors averaged about 3 percent of the range in stage at the tide stations and between 3 and 10 percent of the range in discharge measured in the inlets for the calibration period. Following calibration and verification, the model was applied to three different conditions. The first condition represented the existing physical configuration and typical freshwater inflow. The second condition represented reduced fresh water inflow, and the third represented an alteration of Sanibel Causeway. All three conditions were evaluated through Lagrangian particle tracks and simulated dye injections. Residual circulation patterns were similar for typical and reduced freshwater inflow, but reduced freshwater inflow increased the residence time in the upper harbor by a factor of two or more. Removal of Sanibel Causeway did not significantly affect residual flows in upper and lower Charlotte Harbor, Matlacha Pass, Gasparilla Sound, or the Gulf of Mexico. Analysis of Lagrangian particle tracks indicated changes in residence times in San Carlos Bay as a result of removing Sanibel Causeway, but the changes were not consistent for all particles. The residence time of 8 particles in San Carlos Bay decreased with removal of the causeway, 1 was unchanged, and the residence time of 3 particles increased. Simulated flushing characteristics of the estuarine system were affected more by reduced freshwater inflow than for typical freshwater inflow. After 30 days of simulation of reduced freshwater inflow, 42 percent of the dye injected into the upper harbor remained in the upper harbor, compared to 28 percent for typical freshwater inflow. The upper harbor has a relatively long flushing time because it is not directly

  6. Coastal wetland response to sea level rise in a marine and fluvial estuarine system

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

    . Most of the salt marshes become flooded and some of them migrate under higher SLR scenarios. These examples show how this tool can be used in any estuarine system to project salt marsh productivity and accretion under sea level change scenarios to better interpret responses and improve restoration and planning management decisions.

  7. Multi-element study of sediments from the river Khai River - Nha Trang Bay estuarine system, South China Sea.

    NASA Astrophysics Data System (ADS)

    Koukina, Sofia; Lobus, Nikolai; Peresypkin, Valery; Baturin, Gleb; Smurov, Andrey

    2013-04-01

    Major (Al, Fe, Ti, Mg, Ca, Na, K), minor (Mn) and trace (Cr, Ni, Cd, V, Zn, Cu, Pb, Sb, Bi, Sn, Ag, Li, Co, As, Zr, Mo, Hg) elements along with nutrients (TOC, TS, TP) and TIC were first determined in ten surface sediment samples from the Khai River - Nha Trang Bay estuarine system, South China Sea. According to the sediment quality guidelines and reference background values, most of the element contents that were studied were below the threshold levels, while the content of Ag exceeded significantly the hazardous levels in the most of the samples along the river - sea transect. The local anthropogenic and/or environmental sources of Ag within the region need special study. Aluminum and lithium normalization indicated some specific features in the abundance and distribution of the elements along the salinity gradient. The mean grain size of the sediments decreased from the river part to the bay part of the transect. Sedimentary TOC was relatively low (1-2 %) and showed independent distribution along the river - sea transect in relation to the other elements that were studied. Ca, Ba and Sr distribution showed some sporadic enrichment and were largely controlled by the TIC content in sediments. Sedimentary TP, Al, Fe, Mn, Ti, Na, K, Li, Co, Cs, Zn and V varied within the narrow range and tended to increase seaward. These elements are most likely controlled by the accumulation of their fine grained aluminosilicate host minerals and materials at sites determined by hydrodynamic conditions, i. e., in the sea floor depression. TS, As, Sn, Bi, U, Cd and Mo were relatively low in the sediments studied and tended to decrease seaward with the slight elevation in the intermediate part of the transect. These elements can be scavenged by and/or co-precipitated with the dissolved and particulate materials of the river discharge and further deposited on the river - sea geochemical barrier in the course of estuarine sedimentation. The distribution of Ni, Cr, Zr Cu, Pb, Sb, Hg and

  8. Estuarine circulation-driven entrainment of oceanic nutrients fuels coastal phytoplankton in an open coastal system in Japan

    NASA Astrophysics Data System (ADS)

    Watanabe, Kenta; Kasai, Akihide; Fukuzaki, Koji; Ueno, Masahiro; Yamashita, Yoh

    2017-01-01

    We investigated interactions among seasonal fluctuations in phytoplankton biomass, riverine nutrient flux, and the fluxes of nutrients entrained by estuarine circulation in Tango Bay, Japan, to determine the influence of freshwater inflows to an open bay on coastal phytoplankton productivity. The riverine nutrient flux was strongly regulated by river discharge. Estuarine circulation was driven by river discharge, with high fluxes of nutrients (mean nitrate + nitrite flux: 5.3 ± 3.5 Mg [mega grams]-N day-1) between winter and early spring, enhanced by nutrient supply to the surface water via vertical mixing. In contrast, low-nutrient seawater was delivered to the bay between late spring and summer (1.0 ± 0.8 Mg-N day-1). Seasonal fluctuations in phytoplankton biomass were affected by the entrained fluxes of oceanic nutrients and variation in the euphotic zone depth, and to a lesser degree by the riverine nutrient flux. Bioassays and stoichiometric analyses indicated that phytoplankton growth was limited by nitrogen and/or phosphorus. Both the entrainment of oceanic nutrients and the euphotic zone depth affected the duration and magnitude of blooms. Our findings show that, unlike semi-enclosed bays, seasonal variations in coastal phytoplankton in an open coastal system are primarily fueled by the entrainment of oceanic nutrients and are influenced by both freshwater inflow and coastal conditions (e.g. vertical mixing and wind events).

  9. Comparison of mutagen accumulation in 3 estuarine species using the salmonella/microsome activation system.

    PubMed

    Sparks, T H; Baylis, J R; Chang, C W

    1981-06-01

    3 Estuarine organisms- oysters (Crassostrea virginica), sea squirts (Mogulla sp.), and shrimp (Peneaus sp.)-were examined for Ames test detectable levels of mutagens. Whole-tissue extracts of these organisms were made and tested using S. Typhimurium strains TA98, TA100, TA1535, TA1537 and TA1538, with and without S9 activation. Positive results were obtained with sea squirts and shrimp extracts. Activation was not necessary to show activity. Toxicity was encountered with oyster extracts. Histidine, a possible source of false positives, was eliminated from shrimp extracts using XAD-2 resin and thick-layer chromatography.

  10. Quantification of Sterol and Triterpenol Biomarkers in Sediments of the Cananéia-Iguape Estuarine-Lagoonal System (Brazil) by UHPLC-MS/MS

    PubMed Central

    Bataglion, Giovana Anceski; Koolen, Hector Henrique Ferreira; Weber, Rolf Roland; Eberlin, Marcos Nogueira

    2016-01-01

    Sterols and triterpenols present in sedimentary cores from 12 stations along the Cananéia-Iguape estuarine-lagoonal system were investigated by ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). Ten sterols and three triterpenols were identified and quantified, indicating both natural and anthropogenic sources. The relative distributions of sterol and triterpenol showed that the study area is submitted to organic matter (OM) from the Ribeira de Iguape River, seawater, surrounding vegetation, and plankton production. The contribution of these sources depends on the region of the estuarine-lagoonal system and the depth of sediment. Regarding anthropogenic sources, only the samples submitted to freshwater flow from the Ribeira de Iguape River presented concentration of coprostanol higher than the threshold value and diagnostic ratios, coprostanol/(coprostanol + cholestanol) and coprostanol/cholesterol, that indicate moderate contamination by domestic sewage in that area of the estuarine-lagoonal system. Therefore, the approach used herein identified the OM sources and its transport along the Cananéia-Iguape estuarine-lagoonal system (Brazil), which is a complex of lagoonal channels located in a United Nations Educational, Scientific and Cultural Organization (UNESCO) Biosphere Reserve. PMID:27087811

  11. Solutions Network Formulation Report. The Potential Contribution of the International GPM Program to the NOAA Estuarine Reserves Division's System-wide Monitoring Program

    NASA Technical Reports Server (NTRS)

    Hilbert, Kent; Anderson, Daniel; Lewis, David

    2007-01-01

    Data collected via the International GPM Program could be used to provide a solution for the NOAA Estuarine Reserves Division s System-wide Monitoring Program by augmenting in situ rainfall measurements with data acquired via future satellite-acquired precipitation data. This Candidate Solution is in alignment with the Coastal Management National Application and will benefit society by assisting in estuary preservation.

  12. On Examining the Transport and Transformation of Dissolved Organic Matter in The Albemarle-Pamlico Estuarine System, NC USA

    NASA Astrophysics Data System (ADS)

    Miller, R. L.; Buonassissi, C. J.; Brown, M. M.; Reed, R. E.

    2016-02-01

    The Albemarle-Pamlico Estuarine System (APES) in eastern North Carolina is the second largest estuary and largest lagoonal system in the United States. Variation in the amount of dissolved organic matter (DOM) delivered to the APES was examined for the Neuse and Tar/Pamlico River estuaries, two major components of the APES, using absorption spectra of Chromophoric Dissolved Organic Matter (CDOM). The quality of DOM and transformations that occur during down estuary transport were assessed using the spectral parameters SUVA254, SUVA350, S275-295, S350-400, and Sr calculated from CDOM spectra. We present results from several field campaigns that obtained surface samples during different stages of river discharge, including samples taken following Hurricane Irene (2011), and discuss the utility of using these newer optical indices of DOM quality for examining DOM dynamics in river dominated coastal waters.

  13. SRAO: the first southern robotic AO system

    NASA Astrophysics Data System (ADS)

    Law, Nicholas M.; Ziegler, Carl; Tokovinin, Andrei

    2016-08-01

    We present plans for SRAO, the first Southern Robotic AO system. SRAO will use AO-assisted speckle imaging and Robo-AO-heritage high efficiency observing to confirm and characterize thousands of planet candidates produced by major new transit surveys like TESS, and is the first AO system to be capable of building a comprehensive several-thousand-target multiplicity survey at sub-AU scales across the main sequence. We will also describe results from Robo-AO, the first robotic LGS-AO system. Robo-AO has observed tens of thousands of Northern targets, often using a similar speckle or Lucky-Imaging assisted mode. SRAO will be a moderate-order natural-guide-star adaptive optics system which uses an innovative photoncounting wavefront sensor and EMCCD speckle-imaging camera to guide on faint stars with the 4.1m SOAR telescope. The system will produce diffraction-limited imaging in the NIR on targets as faint as mν = 16. In AO-assisted speckle imaging mode the system will attain the 30-mas visible diffraction limit on targets at least as faint as mν = 17. The system will be the first Southern hemisphere robotic adaptive optics system, with overheads an order of magnitude smaller than comparable systems. Using Robo-AO's proven robotic AO software, SRAO will be capable of observing overheads on sub-minute scales, allowing the observation of at least 200 targets per night. SRAO will attain three times the angular resolution of the Palomar Robo-AO system in the visible.

  14. ESTUARINE HABITAT RESTORATION

    SciTech Connect

    Thom, Ronald M.; Borde, Amy B.

    2015-09-01

    Restoring estuarine habitats generally means repairing damages caused by humans and natural forces. Because of the extensive human occupation, development, and use of coastal areas for centuries, the extensive estuarine habitats have been either destroyed or significantly impaired.

  15. Migration and redistribution of zinc and cadmium in marine estuarine system

    USGS Publications Warehouse

    Holmes, Charles W.; Slade, Elizabeth A.; McLerran, C.J.

    1974-01-01

    A survey of trace-element levels in the estuarine sediments of Texas shows that Corpus Christi Bay has anomalously high concentrations of zinc and cadmium. Maps of elemental abundance within the bay indicate large concentration gradients, the highest values being near the harbor entrance. Seasonal determinations of metal levels in the harbor and bay waters also revealed variations with time. During summer, stagnation of the harbor water increases the concentration of metals so that significant quantities precipitate in the reducing environment of the bottom water. In winter, the exchange of water between the bay and the harbor increases, and metals are redissolved from harbor deposits, washed into the bay, and adsorbed by particles settling to the bottom.

  16. Hydrogeochemical variables regionalization--applying cluster analysis for a seasonal evolution model from an estuarine system affected by AMD.

    PubMed

    Grande, J A; Carro, B; Borrego, J; de la Torre, M L; Valente, T; Santisteban, M

    2013-04-15

    This study describes the spatial evolution of the hydrogeochemical parameters which characterise a strongly affected estuary by Acid Mine Drainage (AMD). The studied estuarine system receives AMD from the Iberian Pyrite Belt (SW Spain) and, simultaneously, is affected by the presence of an industrial chemical complex. Water sampling was performed in the year of 2008, comprising four sampling campaigns, in order to represent seasonality. The results show how the estuary can be divided into three areas of different behaviour in response to hydrogeochemical variables concentrations that define each sampling stations: on one hand, an area dominated by tidal influence; in the opposite end there is a second area including the points located in the two rivers headwaters that are not influenced by seawater; finally there is the area that can be defined as mixing zone. These areas are moved along the hydrological year due to seasonal chemical variations.

  17. Assessment of metal concentrations in muscles of the blue crab, Callinectes danae S., from the Santos Estuarine System.

    PubMed

    Bordon, Isabella C A C; Sarkis, Jorge E S; Tomás, Acácio R G; Scalco, Allan; Lima, Mariana; Hortellani, Marcos A; Andrade, Nathalia P

    2012-09-01

    This study determined the concentrations of eleven metals in the blue crab, Callinectes danae, from nine sites in the Santos Estuarine System of Sao Paulo State, Brazil. The results were compared to guidelines established in the United States, Europe and Brazil for the safety of human consumers. Muscles of blue crabs were removed by dissection and concentrations of Al, Cd, Co, Cr, Cu, Fe, Hg, Mn Ni, Pb and Zn were determined. In general, the concentrations of metals were low, and the crabs were regarded as safe for human consumption. Crabs from a single site (site 4) exceeded the guidelines established by the United States and Europe, but not Brazil, for Pb, with a mean tissue concentration of 1.725 μg g(-1). With the exception of Al, Fe and Ni, significant differences were noted between sites in the concentrations of each metal in crab tissue.

  18. Bioavailability of Riverine Dissolved Organic Matter in an Estuarine System: Evidence of the Priming Effect?

    NASA Astrophysics Data System (ADS)

    Peierls, B. L.; Hounshell, A.; Osburn, C. L.; Paerl, H. W.

    2016-02-01

    As the interface between land and sea, estuaries are highly active zones of biogeochemical cycling driven by material exported from upstream watersheds. Despite large inputs of terrestrial organic matter (OM) from riverine sources, little of that OM is detected in ocean water, suggesting major transformations or losses of OM in estuarine zones. The dissolved organic nitrogen (DON) fraction of terrestrial OM has gained attention as a potential N source for N-limited estuarine phytoplankton, and an understanding of DON bioavailability could provide valuable insight into the fate of allochthonous OM in estuaries. A series of N addition bioassays were used to assess the bioavailability of high molecular weight (HWM, < 1 kDa) river DON to microbial assemblages in the Neuse River Estuary. River DON was isolated from tributary water using tangential flow filtration. Results from these experiments showed that HMW riverine DON additions alone produced no significant short (days) or longer-term (weeks) response in phytoplankton biomass and productivity or bacterial productivity, especially when compared to the effect of inorganic N additions. Phytoplankton biomass and productivity did increase, however, in response to other DON sources, including low molecular weight (< 1 kDa) river DON, waste water treatment effluent, and poultry litter leachate. When inorganic N was added in combination with the HMW river DON, there was greater phytoplankton productivity and biomass relative to nutrient-only controls. This could be evidence of the priming effect, or the enhanced biodegradation of refractory OM by the addition of labile OM. We hypothesize that inorganic N stimulated algal production, and the resulting labile autochthonous OM enhanced river OM mineralization, releasing additional inorganic N for phytoplankton production. On the other hand, the direct stimulation of bacterial metabolism by inorganic N is an alternate possibility and remains to be investigated.

  19. Investigating the fate and transport of fecal coliform contamination in a tidal estuarine system using a three-dimensional model.

    PubMed

    Chen, Wei-Bo; Liu, Wen-Cheng

    2017-03-15

    A three-dimensional fecal coliform transport model was developed and incorporated into a hydrodynamic and suspended sediment transport model to better understand the microbiological water quality in the tidal Tamsui River estuarine system of northern Taiwan, which includes three main tributaries: Dahan River, Xindian River, and Keelung River. The model was calibrated using the water level, salinity, suspended sediment concentration, and fecal coliform data measured in 2010. The predictive skill, a statistical approach, is used to evaluate the model performance. There was quantitatively good agreement between the simulation and measurement results. Further, the calibrated model underwent model sensitivity analysis by varying the model parameters which include the settling velocity, darkness decay rate, partition coefficient, and fecal coliform concentration in the sediment bed. The results indicated that the settling velocity played the most important role in affecting fecal coliform concentrations followed by partition coefficient, darkness decay rate, and fecal coliform concentration in the sediment bed. The model was also used to investigate the effects of salinity and suspended sediment on fecal coliform contamination. The salinity module was excluded in the simulations, resulting in an increase of fecal coliform concentration. However the effect of salinity on fecal coliform concentration is minor. If the suspended sediment transport was excluded in the simulations, the predicted results of fecal coliform concentration decrease to be underestimated the measured data. The modeling results revealed that the inclusion of the suspended sediment transport model in the simulations was of crucial importance because the fecal coliform concentrations were significantly influenced by the suspended sediment concentration in the estuarine system. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Chesapeake Bay nitrogen fluxes derived from a land‐estuarine ocean biogeochemical modeling system: Model description, evaluation, and nitrogen budgets

    PubMed Central

    Friedrichs, Marjorie A. M.; Wilkin, John; Tian, Hanqin; Yang, Qichun; Hofmann, Eileen E.; Wiggert, Jerry D.; Hood, Raleigh R.

    2015-01-01

    Abstract The Chesapeake Bay plays an important role in transforming riverine nutrients before they are exported to the adjacent continental shelf. Although the mean nitrogen budget of the Chesapeake Bay has been previously estimated from observations, uncertainties associated with interannually varying hydrological conditions remain. In this study, a land‐estuarine‐ocean biogeochemical modeling system is developed to quantify Chesapeake riverine nitrogen inputs, within‐estuary nitrogen transformation processes and the ultimate export of nitrogen to the coastal ocean. Model skill was evaluated using extensive in situ and satellite‐derived data, and a simulation using environmental conditions for 2001–2005 was conducted to quantify the Chesapeake Bay nitrogen budget. The 5 year simulation was characterized by large riverine inputs of nitrogen (154 × 109 g N yr−1) split roughly 60:40 between inorganic:organic components. Much of this was denitrified (34 × 109 g N yr−1) and buried (46 × 109 g N yr−1) within the estuarine system. A positive net annual ecosystem production for the bay further contributed to a large advective export of organic nitrogen to the shelf (91 × 109 g N yr−1) and negligible inorganic nitrogen export. Interannual variability was strong, particularly for the riverine nitrogen fluxes. In years with higher than average riverine nitrogen inputs, most of this excess nitrogen (50–60%) was exported from the bay as organic nitrogen, with the remaining split between burial, denitrification, and inorganic export to the coastal ocean. In comparison to previous simulations using generic shelf biogeochemical model formulations inside the estuary, the estuarine biogeochemical model described here produced more realistic and significantly greater exports of organic nitrogen and lower exports of inorganic nitrogen to the shelf. PMID:27668137

  1. Water-quality trends and basin activities and characteristics for the Albemarle-Pamlico estuarine system, North Carolina and Virginia

    USGS Publications Warehouse

    Harned, D.A.; Davenport, M.S.

    1990-01-01

    The Albemarle-Pamlico estuarine system has a total basin area of nearly 31,000 square miles and includes the Neuse, Tar, Pamlico, Roanoke, Chowan, and Alligator Rivers, and the Albemarle, Pamlico, Currituck, Croatan, and Roanoke Sounds. Albemarle Sound receives the greatest freshwater inflow of all the sounds in the estuarine system. Inflow to this sound averages about 13,500 cubic feet per second. Inflow to Pamlico Sound from the Pamlico River averages around 5,400 cubic feet per second, and average inflow into the Neuse River estuary is about 6,100 cubic feet per second. Approximately one-half of the inflow into the system is from ground-water discharge. The Neuse River basin has had the greatest increases in wastewater discharges (650 percent since the 1950's) and had the greatesttotal wastewater discharges of any of the basins in the study area, averaging about 200 million gallons per day in 1988. Wastewater discharges into the Neuse and Tar Rivers were nearly equal to the 7-day, 10-year low flows for these rivers. Land-use data compiled in 1973 for the lower parts of the Neuse River basin and lower part of the Tar-Pamlico River basin indicate that 25 percent of the area was evergreen forest, 25 percent was forested wetlands, 20 percent was cropland and pasture, 12 percent was mixed forest, 10 percent was nonforested wetland, and 4 percent was urban. The amount of nonforested wetland in the part of the study area along the Outer Banks declined 6.5 percent from 1973 to 1983. The numbers of farms and acreage in agricultural use in the study area have declined since the 1920's. A decrease of more than 60 percentin the number of farms was shown between the early 1950's and 1982. Fertilizer sales increased through the 1970's, but declined in the 1980's. Manufacturing employment has increased in the last 30 years, while agricultural employment has decreased. Data from seven stations of the U.S. Geological Survey National Stream Quality Accounting Network were used to

  2. The Future of Southern Ocean Observing Systems

    NASA Astrophysics Data System (ADS)

    Talley, L. D.

    2015-12-01

    Knowledge of the Southern Ocean's role in global climate from seasonal to millennial timescales is evolving, with rapidly increasing recognition of the centrality of the Southern Ocean to Earth's heat, carbon, nutrient, and freshwater budgets, and of the impact of interactions between the ocean and the major ice shelves and grounded ice sheets of Antarctica, which have been decreasing in mass. Observations in this data-sparse and logistically remote region have never been so important, and many nations are rising to the challenge of supporting both experiments and long-term sustained observations. As illustrated in the figure from Meredith et al. (Current Op. Env. Sustain. 2013), autonomous in situ technologies are at the fore because of the difficulty and expense of sending ships year-round and because the crucial satellite remote sensing must be accompanied by in situ observations, including beneath sea ice and ice shelves. The Southern Ocean Observing System (SOOS) has grown out of this recognized need for coordinated observations from the Antarctic coastline northward to the subtropics, from the bottom water production regions in coastal polynyas over the continental shelves, to the regions of interaction of warm ocean waters with Antarctic ice shelves, beneath the vast seasonal sea ice region, and in the hot spots of air-sea fluxes and cross-Antarctic Circumpolar Current (ACC) mixing where the ACC interacts with topography and continental boundaries. The future includes international coordination and collaboration and strengthening of new and existing technologies, which include satellite observing, ice-enabled profiling floats, profiling from marine mammals, moored measurements in many strategic locations, glider and other autonomous operations in all regions, and drilling through floating ice shelves to measure the ocean waters below. Improved and consistent weather observations around the Antarctic coastlines will improve forecasting and reanalysis. Ice

  3. Contaminant Interactions and Biological Effects of Single-walled Carbon Nanotubes in a Benthic Estuarine System

    NASA Astrophysics Data System (ADS)

    Parks, Ashley Nicole

    The fate, bioavailability, bioaccumulation and toxicity of single-walled carbon nanotubes (SWNT) have not been extensively studied to date. Pristine SWNT are highly hydrophobic and have been shown to strongly associate with natural particulate matter in aquatic environments. In light of this, I have focused my research to examine the influence of sediment and food exposure routes on bioavailability, bioaccumulation, and toxicity of structurally diverse SWNT in several ecologically-important marine invertebrate species. No significant mortality was observed in any organism at concentrations up to 1000 mg/kg. Evidence of biouptake after ingestion was observed for pristine semiconducting SWNT using NIRF spectroscopy and for oxidized 14C-SWNT using liquid scintillation counting. After a 24 hour depuration period, the pristine semiconducting SWNT were eliminated from organisms to below the method detection limit (5 microg/mL), and the 14C-SWNT body burden was decreased by an order of magnitude to a bioaccumulation factor (BAF) of <0.01. Neither pristine SWNT nor oxidized 14C-SWNT caused environmentally relevant toxicity or bioaccumulation in benthic invertebrates. Overall, the SWNT were not bioavailable and appear to associate with the sediment. In addition to investigating the toxicity and bioaccumulation of SWNT as an independent toxicant, it is important to consider how they will interact with other contaminants in the environment (i.e., increase or decrease toxicity and bioaccumulation of co-contaminants, alter the environmental transport of co-contaminants, induce degradation of co-contaminants, etc.). I wanted to investigate the effects of SWNT on a complex mixture of contaminants already present in a natural system. New Bedford Harbor (NBH) sediment, which is contaminated with polychlorinated biphenyls (PCBs), was amended with pristine SWNT to determine if the presence of SWNT would mitigate the toxicity and bioaccumulation of the PCBs in deposit

  4. A new tree classification system for southern hardwoods

    Treesearch

    James S. Meadows; Daniel A. Jr. Skojac

    2008-01-01

    A new tree classification system for southern hardwoods is described. The new system is based on the Putnam tree classification system, originally developed by Putnam et al., 1960, Management ond inventory of southern hardwoods, Agriculture Handbook 181, US For. Sew., Washington, DC, which consists of four tree classes: (1) preferred growing stock, (2) reserve growing...

  5. DEVELOPMENT OF NITROGEN LOADING - RESPONSE RELATIONSHIPS FOR ESTUARINE WATERS USING AN EMPIRICAL COMPARATIVE SYSTEMS APPROACH

    EPA Science Inventory

    The U.S. EPA Atlantic Ecology Division (AED) has initiated a multi-year research program to develop empirical nitrogen load-response models for embayments in southern New England. This is part of a multi-regional effort to develop nutrient load-response models for the Gulf of Mex...

  6. DEVELOPMENT OF NITROGEN LOADING - RESPONSE RELATIONSHIPS FOR ESTUARINE WATERS USING AN EMPIRICAL COMPARATIVE SYSTEMS APPROACH

    EPA Science Inventory

    The U.S. EPA Atlantic Ecology Division (AED) has initiated a multi-year research program to develop empirical nitrogen load-response models for embayments in southern New England. This is part of a multi-regional effort to develop nutrient load-response models for the Gulf of Mex...

  7. Dynamics of the southern California current system

    NASA Astrophysics Data System (ADS)

    di Lorenzo, Emanuele

    The dynamics of seasonal to long-term variability of the Southern California Current System (SCCS) is studied using a four dimensional space-time analysis of the 52 year (1949--2000) California Cooperative Oceanic Fisheries Investigations (CalCOFI) hydrography combined with a sensitivity analysis of an eddy permitting primitive equation ocean model under various forcing scenarios. The dynamics of the seasonal cycle in the SCCS can be summarized as follows. In spring upwelling favorable winds force an upward tilt of the isopycnals along the coast (equatorward flow). Quasi-linear Rossby waves are excited by the ocean adjustment to the isopycnal displacement. In summer as these waves propagate offshore poleward flow develops at the coast and the Southern California Eddy (SCE) reaches its seasonal maxima. Positive wind stress curl in the Southern California Bight is important in maintaining poleward flow and locally reinforcing the SCE with an additional upward displacement of isopycnals through Ekman pumping. At the end of summer and throughout the fall instability processes within the SCE are a generating mechanism for mesoscale eddies, which fully develop in the offshore waters during winter. On decadal timescales a warming trend in temperature (1 C) and a deepening trend in the depth of the mean thermocline (20 m) between 1950 and 1998 are found to be primarily forced by large-scale decadal fluctuations in surface heat fluxes combined with horizontal advection by the mean currents. After 1998 the surface heat fluxes suggest the beginning of a period of cooling, which is consistent with colder observed ocean temperatures. The temporal and spatial distribution of the warming is coherent over the entire northeast Pacific Ocean. Salinity changes are decoupled from temperature and uncorrelated with indices of large-scale oceanic variability. Temporal modulation of southward horizontal advection by the California Current is the primary mechanism controlling local

  8. Numerical modeling of tides in the Great Bay Estuarine System: dynamical balance and spring-neap residual modulation

    NASA Astrophysics Data System (ADS)

    McLaughlin, J. W.; Bilgili, A.; Lynch, D. R.

    2003-05-01

    The Great Bay Estuarine System, in New Hampshire, USA, has been the focus area for an attempt to develop a robust finite element method model for estuarine hydrodynamics. Past studies used a nonlinear, time stepping, kinematic model with limited success (Ip et al. Advances in fluid mechanics III, WIT, Southampton (2000) 569; Bilgili et al. J. Geophys. Res. - Oceans 107 (2002); Ertürk et al. Estuar. Coast. Shelf Sci. 47 (1998) 119). We add dynamic physics (that is, local accelerations) for deep-water areas and keep kinematic physics (that is, without local and advective accelerations), with the inclusion of a porous medium beneath the open channel, for shallow and dewatering areas. The choice of which physics set to apply is made on an elemental depth dependent basis. The addition of the local acceleration terms for deep-water areas is seen to greatly improve accuracy in matching of tidal phasing over previous studies. Simulations involving M 2/M 4/M 6 tidal constituents result in strong agreement to observed data from the 1975 Great Bay field program (Swift & Brown, Estuar. Coast. Shelf Sci. 17 (1983) 297), in terms of both tidal heights and cross-section averaged velocities. Comparisons with 10 tidal elevation observation stations and four cross-section averaged current transects show good agreement, displaying average normalized root mean square misfit values of 0.08 and 0.25, respectively. Study of the simulated momentum balance shows the size of the contributions from acceleration terms to be on the order of a third the size of the contributions from the pressure gradient and bottom stress terms. Although relatively small, they are observed to peak at the crucial time of tidal reversal. Application of the model for long-term simulation using an M 2/N 2/S 2 forcing shows the ability to realistically capture the spring-neap cycle. The tidally rectified flow is generally described as a constant spatial pattern with overall amplitude modulation following the

  9. Distribution and sources of aliphatic and polycyclic aromatic hydrocarbons in suspended particulate matter in water from two Brazilian estuarine systems

    NASA Astrophysics Data System (ADS)

    Maioli, Otávio L. G.; Rodrigues, Kamila C.; Knoppers, Bastiaan A.; Azevedo, Débora A.

    2011-07-01

    The levels of selected organic markers, including 17 polycyclic aromatic hydrocarbons (PAHs), 16 of which are classified as priority pollutants by the US-EPA and perylene, aliphatic hydrocarbons (total and linear alkanes) and petroleum biomarkers (hopanes and steranes), were measured in suspended particulate matter (SPM) of the Mundaú-Manguaba estuarine-lagoon system (MMELS) in northeastern Brazil and the Paraíba do Sul River (PSR) estuary in southeastern Brazil, both of which are affected by sugarcane agriculture and urbanization. A total of 33 surface water samples of SPM were collected (22 from the MMELS and 11 from the PSR). The ∑16PAH ranged from 221 to 1243 ng g -1 in the MMELS and from 228 to 1814 ng g -1 in the PSR. Hopane and sterane concentrations in the PSR were higher than in the MMELS due to the input from petrogenic sources in PSR. The contributions of higher plants were also observed by n-alkane analyses. The PAH isomeric ratios indicated that the SPM from MMELS showed characteristics of combustion from biomass or petroleum and PSR was associated to petrogenic input, either from combustion or from unburned petroleum. Three sampling sites located near to the sugarcane plant and mouth of the rivers showed higher PAH concentrations and may largely be considered as highly contaminated. However, levels of n-alkanes and petroleum biomarkers in both study areas were relatively low.

  10. Characteristics of Southern California coastal aquifer systems

    USGS Publications Warehouse

    Edwards, B.D.; Hanson, R.T.; Reichard, E.G.; Johnson, T.A.

    2009-01-01

    Most groundwater produced within coastal Southern California occurs within three main types of siliciclastic basins: (1) deep (>600 m), elongate basins of the Transverse Ranges Physiographic Province, where basin axes and related fluvial systems strike parallel to tectonic structure, (2) deep (>6000 m), broad basins of the Los Angeles and Orange County coastal plains in the northern part of the Peninsular Ranges Physiographic Province, where fluvial systems cut across tectonic structure at high angles, and (3) shallow (75-350 m), relatively narrow fluvial valleys of the generally mountainous southern part of the Peninsular Ranges Physiographic Province in San Diego County. Groundwater pumped for agricultural, industrial, municipal, and private use from coastal aquifers within these basins increased with population growth since the mid-1850s. Despite a significant influx of imported water into the region in recent times, groundwater, although reduced as a component of total consumption, still constitutes a significant component of water supply. Historically, overdraft from the aquifers has caused land surface subsidence, flow between water basins with related migration of groundwater contaminants, as well as seawater intrusion into many shallow coastal aquifers. Although these effects have impacted water quality, most basins, particularly those with deeper aquifer systems, meet or exceed state and national primary and secondary drinking water standards. Municipalities, academicians, and local water and governmental agencies have studied the stratigraphy of these basins intensely since the early 1900s with the goals of understanding and better managing the important groundwater resource. Lack of a coordinated effort, due in part to jurisdictional issues, combined with the application of lithostratigraphic correlation techniques (based primarily on well cuttings coupled with limited borehole geophysics) have produced an often confusing, and occasionally conflicting

  11. Gold coast seaway smartrelease decision support system: optimising recycled water release in a sub tropical estuarine environment.

    PubMed

    Stuart, G; Hollingsworth, A; Thomsen, F; Szylkarski, S; Khan, S; Tomlinson, R; Kirkpatrick, S; Catterall, K; Capati, B

    2009-01-01

    Gold Coast Water is responsible for the management of the water, recycled water and wastewater assets of the City of the Gold Coast on Australia's east coast. Excess treated recycled water is released at the Gold Coast Seaway, a man-made channel connecting the Broadwater Estuary with the Pacific Ocean, on an outgoing tide in order for the recycled water to be dispersed before the tide changes and re-enters the Broadwater estuary. Rapid population growth has placed increasing demands on the city's recycled water release system and an investigation of the capacity of the Broadwater to assimilate a greater volume of recycled water over a longer release period was undertaken in 2007. As an outcome, Gold Coast Water was granted an extension of the existing release licence from 10.5 hours per day to 13.3 hours per day from the Coombabah wastewater treatment plant (WWTP). The Seaway SmartRelease Project has been designed to optimise the release of the recycled water from the Coombabah WWTP in order to minimise the impact to the receiving estuarine water quality and maximise the cost efficiency of pumping. In order achieve this; an optimisation study that involves intensive hydrodynamic and water quality monitoring, numerical modelling and a web-based decision support system is underway. An intensive monitoring campaign provided information on water levels, currents, winds, waves, nutrients and bacterial levels within the Broadwater. This data was then used to calibrate and verify numerical models using the MIKE by DHI suite of software. The Decision Support System will then collect continually measured data such as water levels, interact with the WWTP SCADA system, run the numerical models and provide the optimal time window to release the required amount of recycled water from the WWTP within the licence specifications.

  12. An evaluation of climate change effects in estuarine salinity patterns: Application to Ria de Aveiro shallow water system

    NASA Astrophysics Data System (ADS)

    Vargas, Catarina I. C.; Vaz, Nuno; Dias, João M.

    2017-04-01

    It is of global interest, for the definition of effective adaptation strategies, to make an assessment of climate change impacts in coastal environments. In this study, the salinity patterns adjustments and the correspondent Venice System zonations adaptations are evaluated through numerical modelling for Ria de Aveiro, a mesotidal shallow water lagoon located in the Portuguese coast, for the end of the 21st century in a climate change context. A reference (equivalent to present conditions) and three future scenarios are defined and simulated, both for wet and dry conditions. The future scenarios are designed with the following changes to the reference: scenario 1) projected mean sea level (MSL) rise; scenario 2) projected river flow discharges; and scenario 3) projections for both MSL and river flow discharges. The projections imposed are: a MSL rise of 0.42 m; a freshwater flow reduction of ∼22% for the wet season and a reduction of ∼87% for the dry season. Modelling results are analyzed for different tidal ranges. Results indicate: a) a salinity upstream intrusion and a generalized salinity increase for sea level rise scenario, with higher significance in middle-to-upper lagoon zones; b) a maximum salinity increase of ∼12 in scenario 3 and wet conditions for Espinheiro channel, the one with higher freshwater contribution; c) an upstream displacement of the saline fronts occurring in wet conditions for all future scenarios, with stronger expression for scenario 3, of ∼2 km in Espinheiro channel; and d) a landward progression of the saltier physical zones established in the Venice System scheme. The adaptation of the ecosystem to the upstream relocation of physical zones may be blocked by human settlements and other artificial barriers surrounding the estuarine environment.

  13. Movement patterns of Brook Trout in a restored coastal stream system in southern Massachusetts

    USGS Publications Warehouse

    Snook, Erin L.; Letcher, Benjamin H.; Dubreuil, Todd L.; Zydlewski, Joseph; O'Donnell, Matthew J.; Whiteley, Andrew R.; Hurley, Stephen T.; Danylchuk, Andy J.

    2016-01-01

    Coastal Brook Trout (Salvelinus fontinalis) populations are found from northern Canada to New England. The extent of anadromy generally decreases with latitude, but the ecology and movements of more southern populations are poorly understood. We conducted a 33-month acoustic telemetry study of Brook Trout in Red Brook, MA, and adjacent Buttermilk Bay (marine system) using 16 fixed acoustic receivers and surgically implanting acoustic transmitters in 84 individuals. Tagged Brook Trout used the stream, estuary (50% of individuals) and bay (10% of individuals). Movements into full sea water were brief when occurring. GAMM models revealed that transitions between habitat areas occurred most often in spring and fall. Environmental data suggest that use of the saline environment is limited by summer temperatures in the bay. Movements may also be related to moon phase. Compared to more northern coastal populations of Brook Trout, the Red Brook population appears to be less anadromous overall, yet the estuarine segment of the system may have considerable ecological importance as a food resource.

  14. Hydrothermal system in Southern Grass Valley, Pershing County, Nevada

    SciTech Connect

    Welch, A.H.; Sorey, M.L.; Olmsted, F.H.

    1981-01-01

    Southern Grass Valley is a fairly typical extensional basin in the Basin and Range province. Leach Hot Springs, in the southern part of the valley, represents the discharge end of an active hydrothermal flow system with an estimated deep aquifer temperature of 163 to 176/sup 0/C. Results of geologic, hydrologic, geophysical and geochemical investigations are discussed in an attempt to construct an internally consistent model of the system.

  15. The hydrothermal system in southern Grass Valley, Pershing County, Nevada

    USGS Publications Warehouse

    Welch, Alan H.; Sorey, M.L.; Olmsted, F.H.

    1981-01-01

    Southern Grass Valley is typical extensional basin in the Basin and Range province. Leach Hot Springs, in the southern part of the valley, represents the discharge end of an active hydrothermal flow system with an estimated deep aquifer temperature of 163-173C. This report discusses results of geologic, hydrologic, geophysical and geochemical investigations used in an attempt to construct an internally consistent model of the system. (USGS)

  16. Diatom-inferred hydrological changes and Holocene geomorphic transitioning of Africa's largest estuarine system, Lake St Lucia

    NASA Astrophysics Data System (ADS)

    Gomes, M.; Humphries, M. S.; Kirsten, K. L.; Green, A. N.; Finch, J. M.; de Lecea, A. M.

    2017-06-01

    The diverse lagoons and coastal lakes along the east coast of South Africa occupy incised valleys that were flooded during the rise and subsequent stabilisation of relative sea-level during the Holocene. Sedimentary deposits contained within these waterbodies provide an opportunity to investigate complex hydrological and sedimentological processes, and examine sea-level controls governing system geomorphic evolution. In this paper, we combine diatom and sulfur isotope analyses from two sediment cores extracted from the northern sub-basins of Lake St Lucia, a large shallow estuarine lake that is today largely isolated from direct ocean influence behind a Holocene-Pleistocene barrier complex. Analyses allow the reconstruction of hydrological changes associated with the geomorphic development of the system over the mid-to late Holocene. The sedimentary sequences indicate that St Lucia was a shallow, partially enclosed estuary/embayment dominated by strong tidal flows prior to ∼6200 cal. BP. Infilling was initiated when sea-level rise slowed and stabilised around present day levels, resulting in the accumulation of fine-grained sediment behind an emergent proto-barrier. Diatom assemblages, dominated by marine benthic and epiphytic species, reveal a system structured by marine water influx and characterised by marsh and tidal flat habitats until ∼4550 cal. BP. A shift in the biological community at ∼4550 cal. BP is linked to the development of a back-barrier water body that supported a brackish community. Marine planktonics and enrichments in δ34S suggest recurrent, large-scale barrier inundation events during this time, coincident with a mid-Holocene sea-level highstand. Periodic marine incursions associated with episodes of enhanced storminess and overwash remained prevalent until ∼1200 cal. BP, when further barrier construction ultimately isolated the northern basins from the ocean. This study provides the first reconstruction of the palaeohydrological

  17. Spatial patterns in soil biogeochemical process rates along a Louisiana wetland salinity gradient in the Barataria Bay estuarine system

    NASA Astrophysics Data System (ADS)

    Roberts, B. J.; Rich, M. W.; Sullivan, H. L.; Bledsoe, R.; Dawson, M.; Donnelly, B.; Marton, J. M.

    2014-12-01

    Louisiana has the highest rates of coastal wetland loss in the United States. In addition to being lost, Louisiana wetlands experience numerous other environmental stressors including changes in salinity regime (both increases from salt water intrusion and decreases from the creation of river diversions) and climate change induced changes in vegetation (e.g. the northward expansion of Avicennia germinans (black mangrove) into salt marshes). In this study, we examined how these changes might influence biogeochemical process rates important in regulating carbon balance and the cycling, retention, and removal of nutrients in Louisiana wetlands. Specifically, we measured net soil greenhouse gas fluxes and collected cores for the determination of rates of greenhouse gas production, denitrification potential, nitrification potential, iron reduction, and phosphorus sorption from surface (0-5cm) and subsurface (10-15cm) depths for three plots in each of 4 sites along the salinity gradient: a freshwater marsh site, a brackish (7 ppt) marsh site, a salt marsh (17 ppt), and a Avicennia germinans stand (17 ppt; adjacent to salt marsh site) in the Barataria Bay estuarine system. Most biogeochemical processes displayed similar spatial patterns with salt marsh rates being lower than rates in freshwater and/or brackish marsh sites and not having significantly different rates than in Avicennia germinans stands. Rates in surface soils were generally higher than in subsurface soils. These patterns were generally consistent with spatial patterns in soil properties with soil water content, organic matter quantity and quality, and extractable nutrients generally being higher in freshwater and brackish marsh sites than salt marsh and Avicennia germinans sites, especially in surface soils. These spatial patterns suggest that the ability of coastal wetlands to retain and remove nutrients might change significantly in response to future climate changes in the region and that these

  18. Chronic genetic damages in Geophagus brasiliensis exposed to anthropic impact in estuarine lakes at Santa Catarina coast--southern of Brazil.

    PubMed

    Benincá, Cristiane; Ramsdorf, Wanessa; Vicari, Taynah; de Oliveira Ribeiro, Ciro A; de Almeida, Marina I; Silva de Assis, Helena C; Cestari, Marta Margarete

    2012-04-01

    Biological monitoring through animals exposed to pollutants using biomarkers provides a promising tool for the identification of pollutants that may cause damage to human health and/or to sustainability of ecosystems. The effects of pollutants in fish tissues are important tools to understand the impact of human activities in natural ecosystems. The aim of this work was to study the water quality of two estuarine lakes in Santa Catarina, Brazil (Camacho Lake and Santa Marta Lake). Geophagus brasiliensis is a species widely distributed in Brazil and was used in this work. Comet assays in peripheral red blood and kidney cells, micronucleus tests in peripheral red blood cells, measurements of acetylcholinesterase activity in axial muscle and histopathological analysis of liver were used as biomarkers. Three sampling campaigns were undertaken in November 2004, June 2005 and November 2005. Thirty adult animals were sampled from each of three different sites (P1--Santa Marta Lake, P2 and P3--Camacho Lake). A negative control was sampled in a non-polluted site at Costa Ecological Park, Paraná. The positive control for genotoxicity was obtained by treating animals with copper sulphate. The results showed that both studied lakes are impacted by potential genotoxic substances. Severe lesions in liver of G. brasiliensis were also observed. The inhibition of acetylcholinesterase activity suggests the presence of pesticides or metals in the studied sites. This work shows that the water quality of Santa Marta and Camacho Lakes have been compromised and further control source of pollutants into these ecosystems is required.

  19. Classification for Estuarine Ecosystems: A Review and Comparison of Selected Classification Schemes

    EPA Science Inventory

    Estuarine scientists have devoted considerable effort to classifying coastal, estuarine and marine environments and their watersheds, for a variety of purposes. These classifications group systems with similarities – most often in physical and hydrodynamic properties – in order ...

  20. Classification for Estuarine Ecosystems: A Review and Comparison of Selected Classification Schemes

    EPA Science Inventory

    Estuarine scientists have devoted considerable effort to classifying coastal, estuarine and marine environments and their watersheds, for a variety of purposes. These classifications group systems with similarities – most often in physical and hydrodynamic properties – in order ...

  1. Considerations on the effects of tidal regimes in the movement of floating litter in an estuarine environment: Case study of the estuarine system of Santos-São Vicente, Brazil.

    PubMed

    Fernandino, Gerson; Elliff, Carla Isobel; Frutuoso, Gabriela Amado; Silva, Eric Vinícius Nascimento Malaquias da; Gama, Guilherme Santiago; Sousa, João Henrique de Oliveira; Silva, Iracema Reimão

    2016-09-15

    Floating litter in the estuarine system of Santos-São Vicente is common and is part of day-to-day activities of various users of the area. The objective of the present study was to carry out a quali-quantitative evaluation of the occurrence of floating litter, to infer their sources, and to identify environmental factors that are likely to control occurrence and distribution, with particular emphasis on the effects of tidal regimes. Six sampling stations were selected along the aforementioned estuary and visited monthly between July 2010 and January 2012. Floating litter was counted from a fixed sampling station. Plastics prevailed (89.64%) and their main source was domestic activities (55.41%). More litter was found during ebb spring tides, with higher concentrations obeying confluence patterns of the estuary's channels. Results indicated that occurrence can be attributed to the deficiency in basic sewage system in the area and the deliberate disposal into the estuary by the local population.

  2. The estuarine geochemical reactivity of Zn isotopes and its relevance for the biomonitoring of anthropogenic Zn and Cd contaminations from metallurgical activities: Example of the Gironde fluvial-estuarine system, France

    NASA Astrophysics Data System (ADS)

    Petit, Jérôme C. J.; Schäfer, Jörg; Coynel, Alexandra; Blanc, Gérard; Chiffoleau, Jean-François; Auger, Dominique; Bossy, Cécile; Derriennic, Hervé; Mikolaczyk, Mathilde; Dutruch, Lionel; Mattielli, Nadine

    2015-12-01

    geochemical reactivity of Zn in the estuary rather than signatures of past metallurgical contaminations in the watershed as recorded in contaminated river sediments. The study also shows that the isotopic composition of Zn is strongly fractionated by its geochemical reactivity in the Gironde Estuary, representative of meso-macrotidal estuarine systems.

  3. Estuarine Food Webs

    EPA Science Inventory

    Estuaries provide habitat for abundant plants, animals and micro-organisms, ranging from microscopic plankton (bacteria, yeasts, algae, protozoa) to larger benthic and pelagic organisms (seagrass, clams, crabs, sea trout, pelicans and dolphins). Estuarine biota can be characteri...

  4. Estuarine Food Webs

    EPA Science Inventory

    Estuaries provide habitat for abundant plants, animals and micro-organisms, ranging from microscopic plankton (bacteria, yeasts, algae, protozoa) to larger benthic and pelagic organisms (seagrass, clams, crabs, sea trout, pelicans and dolphins). Estuarine biota can be characteri...

  5. A numerical rating system for crown classes of southern hardwoods

    Treesearch

    James S. Meadows; E.C. Burkhardt; Robert L. Johnson; John D. Hodges

    2001-01-01

    A numerical rating system to delineate crown classes of southern hardwoods is described. The system is based on four criteria: (1) amount of direct sunlight from above, (2) amount of direct sunlight from the sides, (3) crown balance, and (4) relative crown size. The total point value assigned places the tree within one of the four crown classes. The rating system can...

  6. Final Report Collaborative Project. Improving the Representation of Coastal and Estuarine Processes in Earth System Models

    SciTech Connect

    Bryan, Frank; Dennis, John; MacCready, Parker; Whitney, Michael

    2015-11-20

    This project aimed to improve long term global climate simulations by resolving and enhancing the representation of the processes involved in the cycling of freshwater through estuaries and coastal regions. This was a collaborative multi-institution project consisting of physical oceanographers, climate model developers, and computational scientists. It specifically targeted the DOE objectives of advancing simulation and predictive capability of climate models through improvements in resolution and physical process representation. The main computational objectives were: 1. To develop computationally efficient, but physically based, parameterizations of estuary and continental shelf mixing processes for use in an Earth System Model (CESM). 2. To develop a two-way nested regional modeling framework in order to dynamically downscale the climate response of particular coastal ocean regions and to upscale the impact of the regional coastal processes to the global climate in an Earth System Model (CESM). 3. To develop computational infrastructure to enhance the efficiency of data transfer between specific sources and destinations, i.e., a point-to-point communication capability, (used in objective 1) within POP, the ocean component of CESM.

  7. Siak River System — East-Sumatra: Characterisation of sources, estuarine processes, and discharge into the Malacca Strait

    NASA Astrophysics Data System (ADS)

    Siegel, Herbert; Stottmeister, Iris; Reißmann, Jan; Gerth, Monika; Jose, Christin; Samiaji, Joco

    2009-04-01

    Interdisciplinary pollution studies were performed in the Siak River system in the Riau Province of East-Sumatra (Indonesia). Remote sensing investigations combined with in situ measurements in different seasons of the years 2004-2006 were focused on the identification of different sources of water masses in the tributaries and on the discharge into the estuary and Malacca Strait. Ship-borne measurements comprised the determination of the concentration and composition of optically active water constituents and water colour. Satellite data of different spectral and spatial resolution were implemented. Sources of different water masses such as humic substance dominated rivers, erosion areas of high suspended matter concentration and areas of limited bio-productivity are identified. Sources of humic substances are the rivers Tapung Kanan, Mandau, Siak Kecil, and Bukit Batu which are draining peatlands. The absorption coefficients of dissolved organic substances are partly (Siak Kecil, 51.8 m - 1 ) more than double of the currently admitted coefficients. The highest suspended matter concentrations near a channel between Siak and Siak Kecil leading to lowest transparency are caused by the estuarine turbidity maximum developing at the tidal front. The lowest Chlorophyll concentrations were measured between Pekanbaru and the channel, in and downstream of an industrial area. The concentration and distribution of water constituents are characterised by distinct regional patterns independent from the monsoon phases. The high absorption of dissolved organic humic substances originated from draining peatlands shifts the maximum of spectral reflectances to 700 nm leading to the extreme brownish to red-brownish water colour. High scattering of suspended particles increases the reflectance in the entire spectral range. The strong changes in the water colour enables satellite data of the visible spectral range to follow the distribution patterns of the Siak River discharge in the

  8. Computer modeling of fecal coliform contamination of an urban estuarine system.

    PubMed

    Scarlatos, P D

    2001-01-01

    This study is focused on the investigation of the sources, distribution and fate of fecal coliform populations in the North Fork of the New River that flows through the City of Fort Lauderdale, Florida, USA. The dynamics of this brackish river are driven by weak tides, regulated freshwater discharges, overland runoff, storm water drainage from sewers, and groundwater exchange. Extensive field studies failed to document any alleged source(s) of contamination, including birds, domesticated and undomesticated mammals, humans, septic tank leakage, urban runoff, non-point discharges from agricultural lands, waste disposal from live-aboard vessels and/or in situ re-growth of fecal coliform. In order to facilitate field sampling, and support the data analyses efforts, computer simulations were applied to assess the likelihood of the various possible pollution scenarios. The physically based computer model used is the WASP (Water Quality Analysis Simulation Program Modeling System) of the US Environmental Protection Agency. In addition, the Neural Network MATLAB Toolbox was utilized for data analysis. WASP was able to accurately simulate the water hydrodynamics and coliform concentrations within the North Fork, while the neural network assisted in identifying correlations between fecal coliform and the various parameters involved. The numerical results supported the conclusion that fecal coliform were introduced by the animal populations along the riverbanks and by storm water washout of the adjacent drainage basins and the banks. The problem is exaggerated due to the low flashing capacity of the river.

  9. The effect of wind and currents on gas exchange in an estuarine system

    NASA Technical Reports Server (NTRS)

    Broecker, W. S.; Ledwell, J. R.; Bopp, R.

    1987-01-01

    The objectives were to develop a non-volatile tracer to use in gas exchange experiments in laterally unconfined systems and to study applications of deliberate tracers in limnology and oceanography. Progress was made on both fronts but work on the development of the non-volatile tracer proved to be more difficult and labor intensive that anticipated so no field experiments using non-volatile tracers was performed as yet. In the search for a suitable non-volatile tracer for an ocean scale gas exchange experiment a tracer was discovered which does not have the required sensitivity for a large scale experiment, but is very easy to analyze and will be well suited for smaller experiments such as gas exchange determinations on rivers and streams. Sulfur hexafluoride, SF6, was used successfully as a volatile tracer along with tritium as a non-volatile tracer to study gas exchange rates from a primary stream. This is the first gas exchange experiment in which gas exchange rates were determined on a head water stream where significant groundwater input occurs along the reach. In conjunction with SF6, Radon-222 measurements were performed on the groundwater and in the stream. The feasibility of using a combination of SF6 and radon is being studied to determine groundwater inputs and gas exchange of rates in streams with significant groundwater input without using a non-volatile tracer.

  10. Time-varying environmental control of phytoplankton in a changing estuarine system.

    PubMed

    López Abbate, M Celeste; Molinero, Juan Carlos; Guinder, Valeria A; Perillo, Gerardo M E; Freije, R Hugo; Sommer, Ulrich; Spetter, Carla V; Marcovecchio, Jorge E

    2017-12-31

    Estuaries are among the most valuable aquatic systems by their services to human welfare. However, increasing human activities at the watershed along with the pressure of climate change are fostering the co-occurrence of multiple environmental drivers, and warn of potential negative impacts on estuaries resources. At present, no clear understanding of how coastal ecosystems will respond to the non-stationary effect of multiple drivers. Here we analysed the temporal interaction among multiple environmental drivers and their changing priority on shaping phytoplankton response in the Bahía Blanca Estuary, SW Atlantic Ocean. The interaction among environmental drivers and the number of significant direct and indirect effects on chlorophyll concentration increased over time in concurrence with enhanced anthropogenic stress, changing winter climate and wind patterns. Over the period 1978-1993, proximal variables such as nutrients, water temperature and salinity, showed a dominant effect on chlorophyll, whereas in more recent years (1993-2009) climate signals (SAM and ENSO) boosted indirect effects through its influence on precipitation, wind, water temperature and turbidity. Turbidity emerged as the dominant driver of chlorophyll while in recent years acted synergistically with the concentration of dissolved nitrogen. As a result, chlorophyll concentration showed a significant negative trend and a loss of seasonal peaks reflecting a pronounced reorganisation of the phytoplankton community. We stress the need to account for the changing priority of drivers to understand, and eventually forecast, biological responses under projected scenarios of global anthropogenic change. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. OVERVIEW OF GIS APPLICATIONS IN ESTUARINE MONITORING AND ASSESSMENT RESEARCH

    EPA Science Inventory

    Geographic information systems (GIS) tools are now considered integral in estuarine monitoring and assessment research. A synopsis is presented of our estuarine applications of GIS in the Northeast region of the U.S. The applications discussed cover sample site selection, support...

  12. Plantation thinning systems in the Southern United States

    Treesearch

    Bryce J. Stokes; William F. Watson

    1996-01-01

    This paper reviews southern pine management and thinning practices, describes three harvesting systems for thinning, and presents production and cost estimates, and utilization rates. The costs and product recoveries were developed from published sources using a spreadsheet analysis. Systems included tree-length, flail/chip, and cut-to-length. The estimated total...

  13. A vegetation classification system applied to southern California

    Treesearch

    Timothy E. Paysen; Jeanine A. Derby; Hugh Black; Vernon C. Bleich; John W. Mincks

    1980-01-01

    A classification system for use in describing vegetation has been developed and is being applied to southern California. It is based upon a hierarchical stratification of vegetation, using physiognomic and taxonomic criteria. The system categories are Formation, Subformation. Series, Association, and Phase. Formations, Subformations, and Series have been specified for...

  14. Assessing the influence of nutrient reduction on water quality using a three-dimensional model: case study in a tidal estuarine system.

    PubMed

    Liu, Wen-Cheng; Chan, Wen-Ting

    2014-12-01

    A coupled three-dimensional hydrodynamic and water quality model has been developed and applied to the Danshuei River estuarine system and adjacent coastal sea. The water quality model considers various species of nitrogen, phosphorus, organic carbon, and phytoplankton as well as dissolved oxygen and is driven by a three-dimensional hydrodynamic model. The hydrodynamic and water quality models were validated with observations of water surface elevation, velocity, salinity distribution, and water quality parameters. Statistical error analysis shows that predictions of hydrodynamics, salinity, dissolved oxygen, and nutrients from the model simulation quantitatively agreed with the observed data. The validated model was then applied to predict water quality conditions as a result of a reduction in nutrient loadings based on different engineering strategies. The simulated results revealed that the dissolved oxygen concentration would increase significantly and would be higher than 2 mg/L in the main stream and in three tributaries to meet the minimum statutory requirement for dissolved oxygen. Active estuarine management focused on the reduction of anthropogenic nutrient loads is needed for improvement in water quality.

  15. Environmental studies on river water quality with reference to suitability for agricultural purposes: Mahanadi river estuarine system, India--a case study.

    PubMed

    Sundaray, Sanjay Kumar; Nayak, Binod Bihari; Bhatta, Dinabandhu

    2009-08-01

    Hydrochemistry of surface water (pH, specific conductance, total dissolved solids, sulfate, chloride, nitrate, bicarbonate, hardness, calcium, magnesium, sodium, potassium) in the Mahanadi river estuarine system, India was used to assess the quality of water for agricultural purposes. The samples were studied for 31 different stations during six different seasons in the years 2001-2003. Chemical data were used for mathematical calculations (SAR, Na%, RSC, potential salinity, permeability index, Kelly's index, magnesium hazard, osmotic pressure and salt index) for better understanding the suitability river water quality for agricultural purposes. The river water is free from nitrate-nitrogen hazard and has much less osmotic pressure and RSC values. Further there is no complete precipitation of calcium and magnesium in the study area. The results revealed that waters of some polluted stations like Sambalpur down (D/s of Sambalpur town) and Kathjodi (Cuttack) down (D/s of Cuttack town) are unsuitable up to some extent, where as it is quite unsuitable in case of estuarine samples during the pre-monsoon and post-monsoon seasons. The results were verified by USSL and Wilcox diagrams, which show all the fresh water zone samples (low-medium salinity with low sodium) of the study area are in the 'Excellent to good' category and are suitable to irrigate all soils for semi-tolerant and tolerant as well as sensitive crops.

  16. Sources and temporal patterns of polychlorinated biphenyls around a large South American grain-shipping port (Paranaguá Estuarine System, Brazil).

    PubMed

    Combi, Tatiane; Taniguchi, Satie; de Lima Ferreira, Paulo Alves; Mansur, Andressa Vianna; Figueira, Rubens Cesar Lopes; de Mahiques, Michel Michaelovitch; Montone, Rosalinda Carmela; Martins, César C

    2013-05-01

    The Paranaguá Estuarine System (PES) is an important estuarine environment on the Brazilian coast. The economic importance of the PES is mainly related to industries, fuel terminals, and the main South American grain-shipping port. The aim of this work was to determine the vertical distribution of polychlorinated biphenyls (PCBs) in three sediment cores from the PES. The methods included Soxhlet extraction, clean-up, and quantification by gas chromatography with electron capture detection. The concentrations of total PCBs ranged from lower than the detection limit to 6.65 ng g(-1). Low PCB concentrations were detected in P1 and P3, which were collected far away from direct human activities. In P2, the compositional pattern of PCB congeners showed greater concentrations of tetra- and penta-chlorinated congeners associated with urban and port activities near Paranaguá city. The differences in concentrations between the three sediment cores were attributed to the distance of the sampling points in relation to the possible sources of pollution, which are mostly related to Paranaguá city. The vertical distribution of PCBs in the sediment core P2 was related to historical anthropogenic activities. The highest PCB input was from 1970 to the early 1990s, which coincides with a period of greater use of PCBs in Brazil as well as their greater worldwide production.

  17. Spatio-temporal distribution of Atlantic searobins ( Prionotus spp.) in relation to estuarine dynamics (Río de la Plata, Southwestern Atlantic Coastal System)

    NASA Astrophysics Data System (ADS)

    Jaureguizar, A. J.; Waessle, J. A.; Guerrero, R. A.

    2007-06-01

    The relationship between the distributions of Atlantic searobins ( Prionotus punctatus and Prionotus nudigula) and environmental factors was evaluated in the Southwestern Atlantic Coastal Ecosystem (34-41°S). Two hundred and forty-six sampling stations were analyzed between 1993 and 2000 at three different environmental scales (1000, 100, 10 km). The spatial patterns in the Atlantic searobins' distribution were examined by means of cluster analysis while, the BIO-ENV process was used to estimate the associations of the species' distribution with depth, bottom temperature and bottom salinity. The Atlantic searobin species have a persistent spatial distribution pattern in the coastal ecosystem. Prionotus punctatus inhabits the environment influenced by the estuarine waters of the Río de la Plata, while P. nudigula inhabits the coastal shelf system, with wider depth ranges, lower bottom temperatures, and higher bottom salinity. Although both species show a persistent spatial distribution, the patterns change seasonally in an onshore-offshore direction, as well as in a north-south direction. The bottom salinity has the greatest influence on the spatial distribution of both Atlantic searobins, with the variation of both distribution areas being mainly associated with the wind driven discharge of estuarine water from the Río de la Plata.

  18. Epizootic ulcerative syndrome affecting fish in the Zambezi river system in southern Africa.

    PubMed

    Andrew, T G; Huchzermeyer, K D A; Mbeha, B C; Nengu, S M

    2008-11-22

    In late 2006, diseased fish of a variety of species began to appear in the Chobe and upper Zambezi rivers in southern Africa. In April 2007, investigations showed that the levels of pesticides and heavy metals in the tissues of the fish were very low, discounting pollution as an underlying cause for the disease. However, histological evidence showed that the disease closely resembled the epizootic ulcerative syndrome caused by the oomycete Aphanomyces invadans, a serious aquatic pathogen that has been isolated from freshwater and estuarine fish in Japan, south-east Asia, Australia and the usa since the 1970s, but not previously recorded in Africa.

  19. A re-examination of fish estuarine dependence: Evidence for connectivity between estuarine and ocean habitats

    NASA Astrophysics Data System (ADS)

    Able, Kenneth W.

    2005-07-01

    Our understanding of the recruitment of estuarine fishes has been strongly influenced by two views: first, that estuaries are important nurseries and second, that many species are estuarine dependent. Based on an attempt to review the world-wide literature on these topics, it appears that both of these views have merit but could benefit from additional attention and clarification. The term estuarine dependency is used in a variety of ways depending on the author and context and even how one defines estuary. Further, and perhaps most importantly, we often lack the comparative data on habitat use by fishes in the ocean vs. the estuary to make judgments about dependency. To that end we have analyzed the distribution patterns of fish species along the estuarine-coastal ocean ecotone in southern New Jersey, U.S. to evaluate the fish response. As a result, it appears the degree of estuarine use is quite variable among species, as well as at geographic, annual and cohort-specific scales. Thus, further synthesis is necessary and it might focus on: first, more information on fish use in different types of estuaries across a broad geographical range; second, a better understanding of the functional significance of habitats across the habitat landscapes of the estuary-ocean ecotone; third, any further synthesis needs to incorporate of the role of biotic variables (e.g. predation, competition) in order to enhance our understanding of the degree of estuarine dependency; fourth, we need to determine how freshwater flow into estuaries might influence habitat use especially with regard to the potential role of the offshore estuary.

  20. An assessment of agroforestry systems in the southern USA

    Treesearch

    F. C. Zinkhan; D. Evan Mercer

    1997-01-01

    An assessment of the southern USA, based on a survey of land-use professionalsand a review of theliterature, revealed that it is a diverse region with substantial potential for agroforestry to address a combination of problems and opportunities. The survey indicated that silvopastoml systems are the most common form of agroforestry in the region. Increased economic...

  1. An observing system simulation for Southern Ocean carbon dioxide uptake.

    PubMed

    Majkut, Joseph D; Carter, Brendan R; Frölicher, Thomas L; Dufour, Carolina O; Rodgers, Keith B; Sarmiento, Jorge L

    2014-07-13

    The Southern Ocean is critically important to the oceanic uptake of anthropogenic CO2. Up to half of the excess CO2 currently in the ocean entered through the Southern Ocean. That uptake helps to maintain the global carbon balance and buffers transient climate change from fossil fuel emissions. However, the future evolution of the uptake is uncertain, because our understanding of the dynamics that govern the Southern Ocean CO2 uptake is incomplete. Sparse observations and incomplete model formulations limit our ability to constrain the monthly and annual uptake, interannual variability and long-term trends. Float-based sampling of ocean biogeochemistry provides an opportunity for transforming our understanding of the Southern Ocean CO2 flux. In this work, we review current estimates of the CO2 uptake in the Southern Ocean and projections of its response to climate change. We then show, via an observational system simulation experiment, that float-based sampling provides a significant opportunity for measuring the mean fluxes and monitoring the mean uptake over decadal scales. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  2. Spatial variability in surface-water pCO2 and gas exchange in the world's largest semi-enclosed estuarine system: St. Lawrence Estuary (Canada)

    NASA Astrophysics Data System (ADS)

    Dinauer, Ashley; Mucci, Alfonso

    2017-07-01

    The incomplete spatial coverage of CO2 partial pressure (pCO2) measurements across estuary types represents a significant knowledge gap in current regional- and global-scale estimates of estuarine CO2 emissions. Given the limited research on CO2 dynamics in large estuaries and bay systems, as well as the sources of error in the calculation of pCO2 (carbonic acid dissociation constants, organic alkalinity), estimates of air-sea CO2 fluxes in estuaries are subject to large uncertainties. The Estuary and Gulf of St. Lawrence (EGSL) at the lower limit of the subarctic region in eastern Canada is the world's largest estuarine system, and is characterized by an exceptional richness in environmental diversity. It is among the world's most intensively studied estuaries, yet there are no published data on its surface-water pCO2 distribution. To fill this data gap, a comprehensive dataset was compiled from direct and indirect measurements of carbonate system parameters in the surface waters of the EGSL during the spring or summer of 2003-2016. The calculated surface-water pCO2 ranged from 435 to 765 µatm in the shallow partially mixed upper estuary, 139-578 µatm in the deep stratified lower estuary, and 207-478 µatm along the Laurentian Channel in the Gulf of St. Lawrence. Overall, at the time of sampling, the St. Lawrence Estuary served as a very weak source of CO2 to the atmosphere, with an area-averaged CO2 degassing flux of 0.98 to 2.02 mmol C m-2 d-1 (0.36 to 0.74 mol C m-2 yr-1). A preliminary analysis revealed that respiration (upper estuary), photosynthesis (lower estuary), and temperature (Gulf of St. Lawrence) controlled the spatial variability in surface-water pCO2. Whereas we used the dissociation constants of Cai and Wang (1998) to calculate estuarine pCO2, formulations recommended for best practices in open ocean environments may underestimate pCO2 at low salinities, while those of Millero (2010) may result in overestimates.

  3. Marine and Estuarine Pollution.

    ERIC Educational Resources Information Center

    Reish, Donald J.

    1978-01-01

    Presents a literature review of the effects of various pollutants on marine and estuarine organisms, covering publications of 1976-77. This review includes: (1) effects of pesticides, dredging, dumping, sludge, and petroleum hydrocarbons; and (2) diseases and tissue abnormalities. A list of 441 references is also presented. (HM)

  4. Marine and Estuarine Pollution.

    ERIC Educational Resources Information Center

    Reish, Donald J.

    1978-01-01

    Presents a literature review of the effects of various pollutants on marine and estuarine organisms, covering publications of 1976-77. This review includes: (1) effects of pesticides, dredging, dumping, sludge, and petroleum hydrocarbons; and (2) diseases and tissue abnormalities. A list of 441 references is also presented. (HM)

  5. Silvicultural systems for southern bottomland hardwood forests

    Treesearch

    James S. Meadows; John A. Stanturf

    1997-01-01

    Silvicultural systems integrate both regeneration and intermediate operations in an orderly process for managing forest stands. The clearcutting method of regeneration favors the development of species that are moderately intolerant to intolerant of shade. In fact, clearcutting is the most proven and widely used method of successfully regenerating bottomland oak...

  6. Evaluation of the organic matter sources using the δ13C composition of individual n-alkanes in sediments from Brazilian estuarine systems by GC/C/IRMS

    NASA Astrophysics Data System (ADS)

    Maioli, Otávio Luiz Gusso; de Oliveira, Cristiane Rossi; Dal Sasso, Marco Aurélio; Madureira, Luiz Augusto dos Santos; Azevedo, Débora de Almeida; de Aquino Neto, Francisco Radler

    2012-12-01

    The δ13C composition of individual n-alkanes (from C16 to C34) was measured from surface sediments of five Brazilian estuarine systems affected by different organic matter sources, such as harbor area, industries, urban centers and sugar cane crops, in order to determine the origins of the organic matter. The aliphatic hydrocarbon fraction was analyzed by gas chromatography-combustion-isotope ratio mass spectrometry (GC/C/IRMS). The levels of n-alkanes in the studied areas ranged from 0.34 to 18.14 μg kg-1, being relatively low in comparison to high polluted environments. The Carbon Preference Index (CPI) calculated in the C23-C34 range indicates that n-alkanes are mainly inherited from cuticular waxes of higher plants. The δ13C composition of all n-alkanes detected in the sediment samples ranged from -39.6 to -18.3‰ showing different sources for the studied estuarine systems. Through Principal Component Analysis (PCA) it was possible to verify the petrogenic influence in the n-alkane sources, especially in the Paraíba do Sul sediment samples. Differences up to 15‰ of the δ13C values between n-alkanes of odd and even carbon number (C26 and C27) also indicated mixture of petrogenic and biogenic sources in Paraíba do Sul River. High (less negative) δ13C n-alkane values of odd carbon number were obtained from two sampling sites located close to an ethanol plant, indicating residues discharge of sugar cane (C4 plant). Influence of C3 plants that are the main components of dense ombrophile forest was observed in the Itajaí-Açu sediments by the decrease of δ13C (about 10‰ compared to the Paraíba do Sul River δ13C).

  7. Relating watershed nutrient loads to satellite derived estuarine water quality

    EPA Science Inventory

    Nutrient enhanced phytoplankton production is a cause of degraded estuarine water quality. Yet, relationships between watershed nutrient loads and the spatial and temporal scales of phytoplankton blooms and subsequent water quality impairments remain unquantified for most systems...

  8. Relating watershed nutrient loads to satellite derived estuarine water quality

    EPA Science Inventory

    Nutrient enhanced phytoplankton production is a cause of degraded estuarine water quality. Yet, relationships between watershed nutrient loads and the spatial and temporal scales of phytoplankton blooms and subsequent water quality impairments remain unquantified for most systems...

  9. Estuarine-Shelf Interactions,

    DTIC Science & Technology

    1986-01-01

    latter process occurs at the mouth of the Magothy strength of the flow rather than being specified a River, an estuary tributary to Chesapeake Bay...periods. It is also clear, Magothy in the immediate past. As the density though, that significant geographical variability front associated with the...Estuarine Coastal chemical hydrography of the Magothy River, ?tar. Sci., ’)(4), 485-496, 1977. Tech. Rep. XVIR, Ref. 59-2, Chesapeake bay Hachey, H. B

  10. AMBI indices and multivariate approach to assess the ecological health of Vellar-Coleroon estuarine system undergoing various human activities.

    PubMed

    Sigamani, Sivaraj; Perumal, Murugesan; Arumugam, Silambarasan; Preetha Mini Jose, H M; Veeraiyan, Bharathidasan

    2015-11-15

    Estuaries receive a considerable amount of pollutants from various sources. Presently an attempt has been made to assess whether the aquaculture discharges and dredging activities alter the ecological conditions of Vellar-Coleroon estuarine complex. The European Water Framework Directive (WFD) established a framework for the protection of marine waters. In this commission, a variety of indices were used, among them, AMBI (AZTI Marine Biotic Index) indices along with multivariate statistical approach is unique, to assess the ecological status by using macrobenthic communities. Keeping this in view, stations VE-1 and VE-4 in Vellar; CE-6 and CE-7 in Coleroon estuaries showed moderately disturbed with the AMBI values ranging between 3.45 and 3.72. The above said stations were situated near the shrimp farm discharge point and sites of dredging activities. The present study proves that various statistical and biotic indices have great potential in assessing the nature of the ecosystem undergoing various human pressures. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Immigration and early life stages recruitment of the European flounder (Platichthys flesus) to an estuarine nursery: The influence of environmental factors

    NASA Astrophysics Data System (ADS)

    Amorim, Eva; Ramos, Sandra; Elliott, Michael; Bordalo, Adriano A.

    2016-01-01

    Connectivity between coastal spawning grounds and estuarine nurseries is a critical step in the life cycle of many fish species. Larval immigration and transport-associated physical-biological processes are determinants of recruitment success to nursery areas. The recruitment of the European flounder, Platichthys flesus, to estuarine nurseries located at the southern edge of the species distribution range, has been usually investigated during its juvenile stages, while estuarine recruitment during the earlier planktonic life stage remains largely unstudied. The present study investigated the patterns of flounder larval recruitment and the influence of environmental factors on the immigration of the early life stages to the Lima estuary (NW Portugal), integrating data on fish larvae and post-settlement individuals (< 50 mm length), collected over 7 years. Late-stage larvae arrived at the estuary between February and July and peak abundances were observed in April. Post-settlement individuals (< 50 mm) occurred later between April and October, whereas newly-settled ones (< 20 mm) were found only in May and June. Variables associated with the spawning, survival and growth of larvae in the ocean (sea surface temperature, chlorophyll a and inland hydrological variables) were the major drivers of flounder occurrence in the estuarine nursery. Although the adjacent coastal area is characterized by a current system with strong seasonality and mesoscale variability, we did not identify any influence of variables related with physical processes (currents and upwelling) on the occurrence of early life stages in the estuary. A wider knowledge on the influence of the coastal circulation variability and its associated effects upon ocean-estuarine connectivity is required to improve our understanding of the population dynamics of marine spawning fish that use estuarine nurseries.

  12. Citizen participation and discontent in three Southern European health systems.

    PubMed

    Serapioni, Mauro; Matos, Ana Raquel

    2014-12-01

    Participation has featured in political agendas in recent decades and the domain of healthcare has not been indifferent to its appeal. Although emerging later than in other European regions, the involvement of civil society in healthcare decision-making procedures has proved one of the biggest challenges facing Southern European health systems. The health systems of the countries considered in this analysis - Italy, Portugal and Spain - underwent reforms that brought citizen participation to the forefront of the health system. Through national laws or health plans, each of these countries has recognised the need to promote participation in order to 'give a voice' to citizens in the health sector. Accordingly, a range of significant activities have been implemented in the region, although they have been developed unequally within national territories, at different paces and involving the mobilisation of different actors. This article focuses on the most relevant experiences of citizen participation designed and implemented in the three selected countries, describing their key features and potential, as well as the main critical issues and contradictions that have emerged over time. Particular emphasis is given to the impact of the current financial crisis on Southern European national health systems, especially in terms of participatory methods, the way in which citizen participation is progressing and civil society's reaction to these important changes. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Estuarine fluvial floodplain formation in the Holocene Lower Tagus valley (Central Portugal) and implications for Quaternary fluvial system evolution

    NASA Astrophysics Data System (ADS)

    van der Schriek, Tim; Passmore, David G.; Rolão, Jose; Stevenson, Anthony C.

    2007-11-01

    We present a brief synthesis of the Quaternary fluvial record in the Lower Tagus Basin (central Portugal), concentrating on factors controlling infill and incision. The Holocene part of the record forms the focus of this paper and guides the questioning of the basic assumptions of the established Quaternary fluvial evolution model, in particular the link between sea-level change and fluvial incision-deposition. We suggest that several incision-aggradation phases may have occurred during glacial periods. Major aggradation events may overlap with cold episodes, while incision appears to concentrate on the warming limb of climate transitions. The complex stratigraphy of the Quaternary record in the Lower Tagus valley is influenced by repeated base-level and climate changes. This paper submits the first chronostratigraphic framework for valley fill deposits in the Lower Tagus area. Sea-level rise forced aggradation and controlled deposition of the fine-grained sedimentary wedge underlying the low-gradient Lower Tagus floodplain. Investigations have focused on the lower Muge tributary, where rapidly aggrading estuarine and fluvial environments were abruptly established (∼8150 cal BP) as sea level rose. Base level at the valley mouth controlled the upstream extent of the fine-grained backfill. Tidal environments disappeared abruptly (∼5800 cal BP) when the open estuary at the Muge confluence was infilled by the Tagus River. The decrease and final still stand of sea-level rise led to floodplain stabilisation with peat (∼6400-5200 cal BP) and soil formation (∼5200-2200 cal BP). Localised renewed sedimentation (∼2200-200 cal BP) is linked to human activity.

  14. Plant utilization against digestive system disorder in Southern Assam, India.

    PubMed

    Choudhury, Prakash Roy; Choudhury, Manabendra Dutta; Ningthoujam, Sanjoy Singh; Mitra, Abhijit; Nath, Deepa; Talukdar, Anupam Das

    2015-12-04

    Being one of the most common types of life threatening diseases in Southern Assam, India, the digestive system disorders (DSD) have gained much attention in recent decades. Traditional beliefs and inadequate income of mass population result in the use of alternative phytotherapies to treat the diseases. The present paper documents the medicinal knowledge and utilization of plants for treatment of digestive system disorders in Southern Assam, India by Disease Consensus Index (DCI). It also determines the most suitable plant species used to treat digestive system disorders in the study area. The study was based on ethnomedicinal field survey covering a period of 1 year from 2014-2015. The ethnomedicinal information was collected by using semi-structured questionnaires from different traditional Bengali people having knowledge on medicinal plants. Collected data were analyzed by calculating DCI. During the survey, 29 informants were interviewed and a total of 49 plants under 46 genera belonging to 33 families were listed. Data analysis revealed that Litsea glutinosa, Momordica charantia, Andrographis paniculata, Lawsonia inermis, Cleome viscosa, Psidium guajava, Ageratum conyzoides, Cuscuta reflexa, Cynodon dactylon and Carica papaya are the most prominent plants among the people of Southern Assam for treating DSD. This explorative survey emphasizes the need to preserve and document the traditional healing practices for managing DSD inviting for more imminent scientific research on the plants to determine their efficacy as well as safety. With the help of statistical analysis (DCI), we propose 10 priority plants for DSD in present work. Systematic pharmacological study with these plants may contribute significant result. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  15. Relative importance of estuarine flatfish nurseries along the Portuguese coast

    NASA Astrophysics Data System (ADS)

    Cabral, Henrique N.; Vasconcelos, Rita; Vinagre, Catarina; França, Susana; Fonseca, Vanessa; Maia, Anabela; Reis-Santos, Patrick; Lopes, Marta; Ruano, Miguel; Campos, Joana; Freitas, Vânia; Santos, Paulo T.; Costa, Maria José

    2007-02-01

    The relative importance of nursery areas and their relationships with several environmental variables were evaluated in nine estuarine systems along the Portuguese coast based on trawl surveys. Historical data were used to outline changes and trends in the nursery function of some of these estuaries over the past decades. The dominant flatfish species in Portuguese estuaries were Platichthys flesus (Linnaeus, 1758), Solea solea (Linnaeus, 1758), Solea senegalensis Kaup, 1858 and Monochirus hispidus Rafinesque, 1814, but their occurrence differed among the estuaries. P. flesus only occurred in estuaries north of the Tejo estuary (39°N), S. solea was quite rare along the southern Portuguese coast (south of 37°30'N), S. senegalensis occurred in estuaries throughout the coast, but its abundance varied considerably, and the occurrence of M. hispidus was limited to the Sado estuary and Ria Formosa. A Correspondence Analysis was performed to evaluate the relationships between flatfish species abundance and geomorphologic and hydrologic characteristics of estuaries (latitude, freshwater flow, estuarine area, intertidal area, mean depth and residence time). Abiotic characteristics (depth, temperature, salinity, sediment type) of nursery grounds of each flatfish species were also evaluated. Results showed that some estuaries along the Portuguese coast have nursery grounds used by several flatfish species (e.g. Ria de Aveiro, Sado estuary), while in other systems a segregation was noticed, with juveniles of different species occurring in distinct estuarine areas (e.g. Minho and Mondego estuaries). This emphasizes the relevance of niche overlap, but the potential for competition may be considerably minimized by differences in resource use patterns and by an extremely high abundance of resources. Peak densities of flatfishes recorded in nurseries areas along the Portuguese coast were within the range of values reported for other geographical areas. Inter-annual abundance

  16. Estuarine shoreline and barrier-island sandline change assessment

    USGS Publications Warehouse

    Terrano, Joseph F.; Smith, Kathryn E.L.

    2016-01-01

    The Barrier Island and Estuarine Wetland Physical Change Assessment Dataset was created to calibrate and test probability models of barrier island sandline and estuarine shoreline change for study areas in Virginia, Maryland, and New Jersey. The models examined the influence of hydrologic and physical variables related to storm-derived overwash and estuarine shoreline change. Variables were calculated using a transect-based method in a geographic information system (GIS) by creating shoreline-perpendicular lines at regular intervals along the oceanfront shoreline and extrapolating the features from geospatial data, including lidar, bathymetry and aerial imagery. In addition, the data set provides storm-derived barrier island change for Hurricane Sandy, as well as linear rates of change for long-term sandline and estuarine shorelines.

  17. Convergence of estuarine channels

    NASA Astrophysics Data System (ADS)

    Dronkers, Job

    2017-07-01

    Tide-dominated coastal plain estuaries have typically up-estuary convergent tidal channels. Analysis of estuarine characteristics indicates a dependence of the convergence length on relative tidal amplitude, relative intertidal area and river flow velocity. In order to explain these relationships we investigate a condition for continuity of net sediment transport throughout the estuary, corresponding to morphodynamic equilibrium. We show, by using an analytical solution of the tidal equations, that this condition is equivalent to a condition on the convergence length. This condition is evaluated for 21 estuaries in different regions of the world. It appears that the convergence length determined in this way can explain observed convergence lengths for the considered set of estuaries. The dependence of the convergence length on different estuarine characteristics is analysed by solving the fully coupled hydro-morphodynamic equations. We show that this dependence limits the range of variation of the tidal velocity amplitude. The analysis provides insight in the morphological response of estuaries to human interventions. The condition can easily be evaluated to yield an estimate of this response.

  18. Human effects on estuarine shoreline decadal evolution

    NASA Astrophysics Data System (ADS)

    Rilo, A.; Freire, P.; Ceia, R.; Mendes, R. N.; Catalão, J.; Taborda, R.

    2012-04-01

    Due to their sheltered conditions and natural resources, estuaries were always attractive to human activities (industrial, agriculture, residential and recreation). Consequently, the complex interactions between anthropogenic and natural drivers increase estuarine shoreline vulnerability to climate changes impacts. The environmental sustainability of these systems depends on a fragile balance between societal development and natural values that can be further disturbed by climate change effects. This challenging task for scientific community, managers and stakeholders can only be accomplished with interdisplinary approaches. In this context, it seems clear that estuarine management plans should incorporate the concept of change into the planning of policy decisions since these natural dynamic areas are often under human pressure and are recognized as sensitive to climate change effects. Therefore, the knowledge about historical evolution of estuarine shoreline is important to provide new insights on the spatial and temporal dimensions of estuarine change. This paper aims to present and discuss shoreline changes due to human intervention in Tagus estuary, located on the west coast of Portugal. Detailed margins cartography, in a 550m fringe (drawn inland from the highest astronomical tide line), was performed based on 2007 orthophotos (spatial resolution of 0.5 m) analysis. Several classification categories were considered, as urbanized areas, industrial, port and airport facilities, agriculture spaces, green areas and natural zones. The estuarine bed (area bellow the highest astronomical tide line) was also mapped (including human occupation, natural habitats, morpho-sedimentary units) based on the geographic information above and LANSAT 7 TM+ images using image processing techniques. Aerial photographs dated from 1944, 1946, 1948, 1955 and 1958 were analyzed for a set of pilot zones in order to fully understand the decadal shoreline change. Estuarine bed presents

  19. Biogeochemical study of water and bottom sediments from the Khai river - Nha Trang Bay estuarine system, South China Sea

    NASA Astrophysics Data System (ADS)

    Shulga, Natalia; Lobys, Nikolay; Drozdova, Anastasia; Peresypkin, Valery

    2014-05-01

    The present study was carried out in Nha Trang Bay (Southern Vietnam, the South China Sea). The samples of water, suspended matter and bottom sediments were collected in summer 2010-2012 in section from the estuary of the Khai River to the marine part of the bay. The samples were analyzed in the stationary lab of IO RAS, Moscow, by TOC-V-CPH, GC/MS and pirolysis methods. We report here the novel data on sources, transformation and burial of OM coming from the Khai river waters. The investigation is focused on ontent and distribution of suspended matter (SM) in the estuary, dissolved organic carbon (DOC), particulated organic carbon (POC); molecular and group composition of hydrocarbons (n-alkanes, steranes, hopanes) and mercury content in water, SM and bottom sediments. It was found that concentration of POC and SM decrease in the Nha Trang Bay waters from estuary to the open part of the bay. However, major changes in the concentration of SM and POC belong to the zone of salinity gradient.DOC behavior is more stable throughout the study area. Organic-geochemical indicators estimation allowed recognition of genesis and transformation degree of organic matter in the study area. The estuary is characterized by mixed genesis of SM with a predominance of allochthonous organic matter whereas outlying parts of the Nha Trang bay are characterized by autochthonous OM. Composition of OM in sediments reflects regularities identified above, despite of the interannual and seasonal variability in the study area. The investigation reveals a predominance of terrestrial organic matter in the silt sediments of the estuary, transported by the Khai river. Distribution of OM in sediments of marine part of the bay is mosaic, with a predominance of planktonogenic, bacterial or terrestrial input at their complex combination. Local anthropogenic pollution as well as an impact of industrial city effluents are found in river- and seaport areas. According to obtained data sedimentation rate

  20. A comparison of tourists and local visitors to National Estuarine Research Reserve sites

    Treesearch

    Allan Marsinko; William C. Norman; Tiffany J. McClinton

    2001-01-01

    The National Estuarine Research Reserve system serves as a laboratory and classroom where the effects of both natural and human activity can be monitored and studied. Visitors to twelve National Estuarine Research Reserve system sites were surveyed to obtain information about demographics, participation, experience with the system, activities, and opinions. Comparisons...

  1. Ecology of Buzzards Bay: An Estuarine Profile

    DTIC Science & Technology

    1996-09-01

    its environ- mental quality. At the same time, the health of the Buzzards Bay ecosystem, like that of almost all estuarine systems, is clearly...Bay’s undulating shoreline contains numerous natural harbors and coves, which support diverse floral and faunal communities as well as commercial...Because the current and future environmental health of these types of embayments can be directly influenced by activities within contributing watersheds

  2. Development and validation of an experimental life support system for assessing the effects of global climate change and environmental contamination on estuarine and coastal marine benthic communities.

    PubMed

    Coelho, Francisco J R C; Rocha, Rui J M; Pires, Ana C C; Ladeiro, Bruno; Castanheira, José M; Costa, Rodrigo; Almeida, Adelaide; Cunha, Angela; Lillebø, Ana Isabel; Ribeiro, Rui; Pereira, Ruth; Lopes, Isabel; Marques, Catarina; Moreira-Santos, Matilde; Calado, Ricardo; Cleary, Daniel F R; Gomes, Newton C M

    2013-08-01

    An experimental life support system (ELSS) was constructed to study the interactive effects of multiple stressors on coastal and estuarine benthic communities, specifically perturbations driven by global climate change and anthropogenic environmental contamination. The ELSS allows researchers to control salinity, pH, temperature, ultraviolet radiation (UVR), tidal rhythms and exposure to selected contaminants. Unlike most microcosms previously described, our system enables true independent replication (including randomization). In addition to this, it can be assembled using commercially available materials and equipment, thereby facilitating the replication of identical experimental setups in different geographical locations. Here, we validate the reproducibility and environmental quality of the system by comparing chemical and biological parameters recorded in our ELSS with those prevalent in the natural environment. Water, sediment microbial community and ragworm (the polychaete Hediste diversicolor) samples were obtained from four microcosms after 57 days of operation. In general, average concentrations of dissolved inorganic nutrients (NO3 (-) ; NH4 (+) and PO4 (-3) ) in the water column of the ELSS experimental control units were within the range of concentrations recorded in the natural environment. While some shifts in bacterial community composition were observed between in situ and ELSS sediment samples, the relative abundance of most metabolically active bacterial taxa appeared to be stable. In addition, ELSS operation did not significantly affect survival, oxidative stress and neurological biomarkers of the model organism Hediste diversicolor. The validation data indicate that this system can be used to assess independent or interactive effects of climate change and environmental contamination on benthic communities. Researchers will be able to simulate the effects of these stressors on processes driven by microbial communities, sediment and seawater

  3. Application of Organic Carbon and Nitrogen Stable Isotope and C/N Ratios as Source Indicators of Organic Matter Provenance in Estuarine Systems: Evidence from the Tay Estuary, Scotland

    NASA Astrophysics Data System (ADS)

    Thornton, S. F.; McManus, J.

    1994-03-01

    The source of particulate organic matter (POM) in lacustrine and estuarine sediments from the Tay River catchment has been evaluated using stable carbon and nitrogen isotope and elemental C/N ratios. The δ 13C, δ 15N and C/N compositions of POM from the two environments (respectively -25·4 to -28·0%, 0·2 to 4·0%, 12·17 to 19·5 and -23·2 to -26·6%, 2·6 to 10·6%, 9·03 to 15·71) were statistically distinct, enabling, by use of a simple two component mixing equation, assessment of the ability of each tracer to estimate the terrigenous flux to the estuarine organic matter pool. Estuarial mixing of terrigenous, indigenous estuarine and marine derived organics, recorded by δ 13C data, was only partly confirmed by equivalent δ 15N and C/N compositions which reflected greater control by organic matter diagenesis and biological processing. Limited data indicate sewage derived contributions are insignificant. Of the three tracers employed, only δ 13C ratios are reliable as provenance indicators. Both δ 15N and C/N ratios are limited because the original POM source signature may be lost or overprinted by biochemical alteration prior to and/or soon after deposition. The simultaneous application of these tracers provides substantially more information regarding the source, quality and turnover of sedimentary POM in these contrasting systems than could be achieved using one technique alone.

  4. Southern Africa Validation of NASA's Earth Observing System (SAVE EOS)

    NASA Technical Reports Server (NTRS)

    Privette, Jeffrey L.

    2000-01-01

    Southern Africa Validation of EOS (SAVE) is 4-year, multidisciplinary effort to validate operational and experimental products from Terra-the flagship satellite of NASA's Earth Observing System (EOS). At test sites from Zambia to South Africa, we are measuring soil, vegetation and atmospheric parameters over a range of ecosystems for comparison with products from Terra, Landsat 7, AVHRR and SeaWiFS. The data are also employed to parameterize and improve vegetation process models. Fixed-point and mobile "transect" sampling are used to collect the ground data. These are extrapolated over larger areas with fine-resolution multispectral imagery. We describe the sites, infrastructure, and measurement strategies developed underSAVE, as well as initial results from our participation in the first Intensive Field Campaign of SAFARI 2000. We also describe SAVE's role in the Kalahari Transect Campaign (February/March 2000) in Zambia and Botswana.

  5. Morphological and molecular evidence on the existence of a single estuarine and rocky intertidal acanthocephalan species of Profilicollis Meyer, 1931 (Acanthocephala: Polymorphidae) along the Atlantic and Pacific coasts of southern South America.

    PubMed

    Rodríguez, Sara M; Diaz, Julia I; D'Elía, Guillermo

    2017-03-23

    Profilicollis chasmagnathi Holcman-Spector, Mañé-Garzón & Dei-Cas, 1977 (Acanthocephala: Polymorphidae) has been reported to parasitise different grapsid species as intermediate hosts along the South Atlantic shores, i.e. Cyrtograpsus angulatus (Dana) and Neohelice granulata (Dana) in Uruguay and Cyrtograpsus altimanus (Rathbun) in Argentina. Larvae of a similar acanthocephalan described as Profilicollis antarcticus Zdzitowiecki, 1985 were recorded in the crab Hemigrapsus crenulatus (Milne-Edwards) from an estuarine habitat on the Southeast Pacific shore in Chile. Earlier studies have questioned the specific assignation of the Chilean estuarine populations of Profilicollis Meyer, 1931. The aim of this study was to re-examine the identification of these acanthocephalans by means of morphological and molecular analyses of cystacanths of Profilicollis spp. gathered from C. angulatus, N. granulata, C. altimanus and H. crenulatus. Our analyses showed that a single species of Profilicollis, P. chasmagnathi, parasitises these four crab species. The assessment of specimens from the South Shetlands Islands, the type-locality of P. antarcticus, is needed before formally proposing that P. antarcticus is a junior subjective synonym of P. chasmagnathi.

  6. Hydrodynamic behavior of the Cape Fear River and estuarine system: A synthesis and observational investigation of discharge-salinity intrusion relationships

    NASA Astrophysics Data System (ADS)

    Becker, May Ling; Luettich, Richard A., Jr.; Mallin, Michael A.

    2010-07-01

    Transport of constituents in partially mixed estuaries depends on the relative strengths of dominant forcing mechanisms which may include tides, river input, and wind. In this study, we investigated the major physical mechanisms that influence the salinity structure in the Cape Fear River Estuary (CFRE), a partially mixed estuary that is representative of river-dominated estuaries along the southeast Atlantic coast of the U.S. Based on analysis of observed hydrographic and hydrodynamic data, we first describe differences in velocity, salinity, and stratification at along-channel sections of the estuary for relatively low-flow conditions. We then investigate the influence of river inflow on the salinity intrusion (defined by the 1-salinity contour near the bottom), based on six methods of choosing discharge in order to identify an appropriate means of incorporating flow history into the discharge value. Our analyses indicate: 1) 92 percent of the variability in the length of the salinity intrusion over a five-year period can be explained based on the Hydrologic Flood Method identified in this work, 2) the salinity intrusion depends more weakly on discharge than predicted by classic analytical relationships for exchange-dominated systems in which the intrusion varies with discharge to the power of (-1/3), and 3) intra-tidal and tidal-range differences based on a 29-day modulation significantly influence the salinity structure. Our results suggest that the salinity intrusion location is dependent upon the hydrologic "flood," defined by a peak in the river-discharge hydrograph. The analysis indicates that the new method used to determine discharge in the CFRE can more accurately explain river inflow-salinity relationships than previously investigated methods. In river-estuary systems in which hydrologic flood peaks are large relative to base flow, we hypothesize the hydrologic flood model offers a useful tool for predicting the estuarine salinity response to river

  7. Tidal-Fluvial and Estuarine Processes in the Lower Columbia River: II. Water Level Models, Floodplain Wetland Inundation, and System Zones

    SciTech Connect

    Jay, David A.; Borde, Amy B.; Diefenderfer, Heida L.

    2016-04-26

    Spatially varying water-level regimes are a factor controlling estuarine and tidal-fluvial wetland vegetation patterns. As described in Part I, water levels in the Lower Columbia River and estuary (LCRE) are influenced by tides, river flow, hydropower operations, and coastal processes. In Part II, regression models based on tidal theory are used to quantify the role of these processes in determining water levels in the mainstem river and floodplain wetlands, and to provide 21-year inundation hindcasts. Analyses are conducted at 19 LCRE mainstem channel stations and 23 tidally exposed floodplain wetland stations. Sum exceedance values (SEVs) are used to compare wetland hydrologic regimes at different locations on the river floodplain. A new predictive tool is introduced and validated, the potential SEV (pSEV), which can reduce the need for extensive new data collection in wetland restoration planning. Models of water levels and inundation frequency distinguish four zones encompassing eight reaches. The system zones are the wave- and current-dominated Entrance to river kilometer (rkm) 5; the Estuary (rkm-5 to 87), comprised of a lower reach with salinity, the energy minimum (where the turbidity maximum normally occurs), and an upper estuary reach without salinity; the Tidal River (rkm-87 to 229), with lower, middle, and upper reaches in which river flow becomes increasingly dominant over tides in determining water levels; and the steep and weakly tidal Cascade (rkm-229 to 234) immediately downstream from Bonneville Dam. The same zonation is seen in the water levels of floodplain stations, with considerable modification of tidal properties. The system zones and reaches defined here reflect geological features and their boundaries are congruent with five wetland vegetation zones

  8. pp iii The importance of high-resolution monitoring in erosion and deposition dynamics studies: examples from estuarine and fluvial systems

    NASA Astrophysics Data System (ADS)

    Lawler, D. M.

    2005-01-01

    Erosion and deposition processes lie at the centre of geomorphological explanation, but progress in understanding has been limited by a lack of appropriate high-resolution monitoring methodologies which permit detection of erosion and deposition dynamics. This paper presents a case for monitoring erosion and deposition at high temporal resolutions, and uses hypothetical approaches supported by example erosion and deposition events and analyses drawn from estuarine and fluvial systems. The paper first presents testable hypotheses to demonstrate the complexity of possible event combinations, sequences and juxtapositions for the erosion driving forces which underpin the need for high-resolution monitoring. Second, it summarises recent improvements to the Photo-Electronic Erosion Pin (PEEP) automatic erosion and deposition monitoring system, including the novel concept of Thermal Consonance Timing (TCT), which is particularly promising because it helps to define the timing of nocturnal events and through the entire hydrograph. Third, example results are discussed from high-resolution monitoring of bank erosion at a tidal site at Burringham on the River Trent in northern England. Tidal banks are revealed to be much more dynamic than previous conventional monitoring has indicated. A key result is that, because the high-resolution approach allows erosional and depositional activity to be assigned to specific periods of tidal inundation, it becomes possible for the first time routinely to produce 'event-based' erosion (36 mm h -1) and deposition rates (4.5 and 8.4 mm h -1). Such rate determinations are potentially very useful in the field validation of sedimentological and geomorphological models, including grain settling and resuspension theory. Fourth, through a longer term of aggregated daily data, a striking 2-week cycle of deposition and erosion emerges which correlates most strongly with spring-neap tidal cycling, but is moderated by wind stress effects. Sediment was

  9. Geodynamics of flat-slab subduction, sedimentary basin development, and hydrocarbon systems along the southern Alaska convergent plate margin

    NASA Astrophysics Data System (ADS)

    Finzel, Emily S.

    Combining field-based geologic studies and numerical modeling provides a robust tool for evaluating the geodynamics of convergent margins. Southern Alaska is arguably the most tectonically active part of the convergent margin of western North America. This conceptual approach has been used to interpret the modern basin dynamics, as well as key stages in the Cenozoic development of this region, including spreading-ridge and flat-slab subduction. New macrofossil, palynological, and lithostratigraphic data for the Bear Lake Formation in the Bristol Bay retroarc basin allow us to construct the first chronostratigraphic framework for this formation, and indicate deposition during Middle and Late Miocene time in a regional transgressive estuarine depositional system. In the Cook Inlet forearc basin, new detrital zircon U-Pb geochronology, rare earth element geochemistry, and clast compositional data from middle Eocene-Pliocene strata demonstrate the importance of sediment sources located in the retroarc region and along strike within the basin. The Yakutat microplate has recently been reinterpreted to represent buoyant crust that is presently subducting at a shallow angle beneath southern Alaska. Integration of stratigraphic, geochronologic, and thermochronologic data indicate that in the flat-slab region, exhumation initiated ca. 43 Ma and migrated inboard, magmatism ceased at ca. 32 Ma, and deposition in sedimentary basins ended by ca. 23 Ma. Sedimentary basins positioned along the western and northern perimeter of the flat-slab region record enhanced subsidence and sediment delivery from the flat-slab region beginning in late Oligocene and middle Miocene time respectively. The discrete contributions of unique driving forces for lithospheric deformation in western Canada and Alaska have not been quantified in detail, so their relative role in influencing deformation has remained unresolved. Using finite element models, we calculate a continuous strain rate and velocity

  10. Diamondback terrapins, Malaclemys terrapin, as a sentinel species for monitoring mercury pollution of estuarine systems in South Carolina and Georgia, USA.

    PubMed

    Blanvillain, Gaëlle; Schwenter, Jeffrey A; Day, Rusty D; Point, David; Christopher, Steven J; Roumillat, William A; Owens, David W

    2007-07-01

    Total mercury concentrations were measured in diamondback terrapin blood and scutes collected from four sites in South Carolina, USA, and at a superfund site in Brunswick, Georgia, USA. There was a strong correlation between mercury concentrations in the two terrapin body compartments (Kendall's tau = 0.79, p < 0.001). Mercury concentrations in terrapin scute and blood and in salt marsh periwinkles, Littoraria irrorata, were significantly higher in Brunswick (scute x = 3810.2 ng/g, blood x = 746.2 ng/g) than from all other sites (scute x = 309.5 ng/g, blood x = 43.2 ng/g, p < 0.001). Seasonal fluctuations of total mercury in the blood and scutes of terrapins collected in the Ashley River, South Carolina, were significantly lower in August than in April, June, or October in blood (p < 0.001); however, scute concentrations did not vary seasonally. Overall, we found higher concentrations of mercury in the scutes of females than males (n = 32, p < 0.05). Larger females may preferentially prey on larger food items, like large periwinkles, which had significantly higher mercury levels in their body tissues than smaller periwinkles (p < 0.001). Methylmercury levels in terrapin scutes were measured, revealing that 90% of the total mercury stored in this compartment was in the organic form. A methylmercury biomagnification factor of 173.5 was calculated from snails to terrapin scutes, and we found that mercury levels in scutes were representative of the mercury levels in other compartments of the ecosystem. These findings show that terrapin scutes are good predictors of mercury pollution and that this species could be used as a bioindicator for assessing mercury contamination of estuarine systems.

  11. Habitat- and bay-scale connectivity of sympatric fishes in an estuarine nursery

    NASA Astrophysics Data System (ADS)

    Dance, Michael A.; Rooker, Jay R.

    2015-12-01

    Acoustic telemetry was used to examine habitat- and bay-scale connectivity for co-occurring juvenile fishes, southern flounder (Paralichthys lethostigma) and red drum (Sciaenops ocellatus), at two spatial scales in a model estuarine seascape. An acoustic positioning system was deployed to examine habitat-scale (ca. 1 m-1 km) movement, while a larger gridded array was deployed to examine bay-scale movement (ca. 1-20 km). Both species exhibited greater use of edge habitat and seagrass beds at the habitat scale; however, rates of movement within habitats varied between species. Southern flounder movement (mean = 4.0 m min-1) increased with decreasing habitat complexity (seagrass to bare sand) and increasing temperature, while red drum rate of movement (mean = 8.4 m min-1) was not significantly affected by environmental factors at the habitat scale, indicating the use of different foraging strategies (i.e. ambush vs. active). Bay-scale distribution was influenced by physicochemical conditions and seascape composition, with both species found most frequently in areas with high seagrass coverage and relative close proximity to tidal creeks and connective channels. Response to environmental variables often differed between species and the probability of bay-scale movement (>1 km) for southern flounder was greatest on days with narrow tidal ranges (<0.4 m) and higher temperatures (>17 °C), while the probability of bay-scale movement for red drum increased in response to decreasing salinity and lower temperatures (<16 °C). Species-specific variation in movement patterns within and across habitat types observed here at both the habitat and bay scale suggest sympatric species employ different strategies to partition resources within estuarine nursery areas and highlight the importance of multi-species assessments for improving our understanding of habitat value and ecosystem function.

  12. 15 CFR 921.52 - Promotion and coordination of estuarine research.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Research Projects § 921.52 Promotion and coordination of estuarine research. (a) NOAA will promote and coordinate the use of the National Estuarine Research Reserve System for research purposes. (b) NOAA will, in...) NOAA will consult with other Federal and state agencies to promote use of one or more research...

  13. 15 CFR 921.52 - Promotion and coordination of estuarine research.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Research Projects § 921.52 Promotion and coordination of estuarine research. (a) NOAA will promote and coordinate the use of the National Estuarine Research Reserve System for research purposes. (b) NOAA will, in...) NOAA will consult with other Federal and state agencies to promote use of one or more research...

  14. 15 CFR 921.52 - Promotion and coordination of estuarine research.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Research Projects § 921.52 Promotion and coordination of estuarine research. (a) NOAA will promote and coordinate the use of the National Estuarine Research Reserve System for research purposes. (b) NOAA will, in...) NOAA will consult with other Federal and state agencies to promote use of one or more research...

  15. 15 CFR 921.52 - Promotion and coordination of estuarine research.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Research Projects § 921.52 Promotion and coordination of estuarine research. (a) NOAA will promote and coordinate the use of the National Estuarine Research Reserve System for research purposes. (b) NOAA will, in...) NOAA will consult with other Federal and state agencies to promote use of one or more research...

  16. Mantle flow field in the southern Ryukyu subduction system

    NASA Astrophysics Data System (ADS)

    Lin, S.; Kuo, B.

    2012-12-01

    The Okinawa trough in the Ryukyu subduction system is the only active back arc basin formed within a continental lithosphere. Recent shear-wave splitting measurements show variable fast directions along the trough suggesting complex three-dimensional flow field in the mantle wedge. In this study we use numerical subduction models to explore the effects of plate thickness variations caused by non-uniform lithospheric stretching on the dynamics in the southern Ryukyu subduction system. We calculate orientations of infinite strain axes as a proxy for olivine lattice preferred orientations and orientations of seismic anisotropy. Our models demonstrate that flow patterns may vary significantly with depth near the plate edge as a result of the along-arc variations in lithospheric thickness. The model results show that the toroidal circulation around the lateral slab edge predominates at greater depths. The thick neighboring lithosphere acts as an effective barrier of the lateral mass exchanges in the shallow portion of the mantle wedge. The wedge material is drawn in horizontally toward the plate edge from the central region of the subduction zone induced by pressure gradients, opposite to the inwards lateral flow at greater depths. Model predictions for the lattice preferred orientations of olivine aggregates agree reasonably well with the observed shear-wave splitting patterns. The results suggest that the depth-varying flow field near the subduction zone edge and the westward flow components in the shallow portion of the mantle wedge may contribute to complex patterns of seismic anisotropy and arc isotopic systematics.

  17. Recognition and dynamics of syntectonic sediment routing systems, southern Pyrenees

    NASA Astrophysics Data System (ADS)

    Allen, P. A.; Duller, R.; Fordyce, S.; Smithells, R.; Springett, J.; Whitchurch, A.; Whittaker, A.; Carter, A.; Fedele, J.-J.

    2009-04-01

    The erosional, transportational and depositional aspects of the biogeochemical cycles involving particulate sediment and solutes are integrated in sediment routing systems. The component parts of these tectonic-geomorphic systems communicate with each other, especially in response to changes in external forcing mechanisms such as tectonic perturbations and climate change; that is, sediment routing systems are characterized by important teleconnections. We are only just beginning to understand how these teleconnections work, and what it means for the spatial and temporal scales of system behaviour. One strategy for investigating the dynamics of sediment routing systems is to link information on the denudation of upstream source regions with downstream patterns of deposition. This is most likely to be fruitful where upstream catchments are tectonically active. Sediment is released into basins whose long-term subsidence is also controlled by tectonic activity. The spatial distribution of subsidence and the magnitude of the sediment discharge from the catchment are critical factors in the dispersal of sediment of different grain size and composition away from a mountain front. We investigate the coarse clastic sediment routing systems of mid-late Eocene age (40-34 Ma) that were deposited in basins located at the boundary of the Axial Zone and the thrust belt of the South-Central Unit on the southern flank of the Pyrenees, Spain. Most of the fan deposits of interest are found in the Pobla Basin, situated north of Tremp, which benefits from outstanding exposure conditions and rigorous previous work on biostratigraphy, magnetostratigraphy and sedimentology (Mellere 1993; Beamud et al. 2003). Distinct fan depositional systems can be identified and mapped on the basis of their sediment composition, detrital thermochronology, facies and architectures, which can be related to correspondingly distinct catchment properties (size, location, exhumational history, lithologies

  18. The Southern Washington Cascades magmatic system imaged with magnetotellurics

    NASA Astrophysics Data System (ADS)

    Bowles-martinez, E.; Bedrosian, P.; Schultz, A.; Hill, G. J.; Peacock, J.

    2016-12-01

    The goal of the interdisciplinary iMUSH project (Imaging Magma Under Saint Helens) is to image the magmatic system of Mount Saint Helens (MSH), and to determine the relationship of this system to the greater Cascades volcanic arc. We are especially interested in an anomalously conductive crustal zone between MSH and Mount Adams known as the Southern Washington Cascades Conductor (SWCC), which early studies interpreted as accreted sediments, but more recently has been interpreted as a broad region of partial melt. MSH is located 50 km west of the main arc and is the most active of the Cascade volcanoes. Its 1980 eruption highlighted the need to understand this potentially hazardous volcanic system. We use wideband magnetotelluric (MT) data collected in 2014-2015 along with data from earlier studies to create a 3D model of the electrical resistivity throughout the region, covering MSH as well as Mount Adams and Mount Rainier along the main volcanic arc. We look at not only the volcanoes themselves, but also their relationship to one another and to regional geologic structures. Preliminary modeling identifies several conductive features, including a mid-crustal conductive region between MSH and Mount Adams that passes below Indian Heaven Volcanic Field and coincides with a region with a high Vp/Vs ratio identified in the seismic component of iMUSH. This suggests that it could be magmatic, but does not preclude the possibility of conductive sediments. Synthesis of seismic and MT data to address this question is ongoing. We also note a conductive zone running north-south just west of MSH that is likely associated with fluids within faults of the Saint Helens Seismic Zone. We finally note that curvature of the conductive lineament that defines the main Cascade arc suggests that the boundary of magmatism is influenced by compression within the Yakima Fold and Thrust Belt, east and southeast of Mount Adams.

  19. Environmental availability of potentially toxic elements in estuarine sediments of the Cananéia-Iguape coastal system, Southeastern Brazil.

    PubMed

    Tramonte, Keila Modesto; Figueira, Rubens Cesar Lopes; de Lima Ferreira, Paulo Alves; Ribeiro, Andreza Portella; Batista, Miriam Fernanda; de Mahiques, Michel Michaelovitch

    2016-02-15

    The Cananéia-Iguape system is located in a Southeastern Brazilian coastal region, acknowledged by UNESCO as Biosphere Reserve of the Atlantic Rainforest. This system underwent important environmental changes due to the opening of the artificial channel of Valo Grande and by past intensive Pb ore mining activities. In view of this scenario, this study evaluated Cu, Pb and Zn availability in sediments from Cananéia-Iguape system, based on the content associated with the main components of the sediments. Moreover, in order to assess local contamination, the metals' contents were compared to Canadian quality guidelines, the past levels of metals preceding the mining activities and background sediment values. Concerning Cu and Zn in a state of chemical remobilization, both elements would possibly present no harm to the local communities. However, Pb available content exceeded the comparison values in various sampling sites, suggesting the need of monitoring regarding its bioavailability. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Cumulative impact of marinas on estuarine water quality

    NASA Astrophysics Data System (ADS)

    McAllister, T. L.; Overton, M. F.; Brill, E. D.

    1996-05-01

    The purpose of this work is to present a modeling approach for assessing and managing the cumulative impact of marinas on estuarine systems. In doing so, both a water-quality model and a planning and management model are developed. The water-quality model predicts biochemical oxygen demand (BOD) and fecal coliform (FC) loadings from marina sources in a hypothetical North Carolina estuary. By running the water-quality model repeatedly with varied loading input, impact coefficients are determined. These impact coefficients are used in the planning and management model, the output of which gives the sizes and locations of marinas in the estuarine system such that dissolved oxygen (DO) and FC water-quality standards are maintained. Five different estuarine development scenarios are considered. Each scenario is evaluated with respect to both maximum and uniform land development constraints. In addition, two alternative fecal coliform standards are used with each of the development options.

  1. Cumulative Impact of Marinas on Estuarine Water Quality

    PubMed

    McAllister; Overton; Brill

    1996-05-01

    The purpose of this work is to present a modeling approach for assessing and managing the cumulative impact of marinas on estuarine systems. In doing so, both a water-quality model and a planning and management model are developed. The water-quality model predicts biochemical oxygen demand (BOD) and fecal coliform (FC) loadings from marina sources in a hypothetical North Carolina estuary. By running the water-quality model repeatedly with varied loading input, impact coefficients are determined. These impact coefficients are used in the planning and management model, the output of which gives the sizes and locations of marinas in the estuarine system such that dissolved oxygen (DO) and FC water-quality standards are maintained.Five different estuarine development scenarios are considered. Each scenario is evaluated with respect to both maximum and uniform land development constraints. In addition, two alternative fecal coliform standards are used with each of the development options.

  2. Impact of biodiversity-climate futures on primary production and metabolism in a model benthic estuarine system

    PubMed Central

    2011-01-01

    Background Understanding the effects of anthropogenically-driven changes in global temperature, atmospheric carbon dioxide and biodiversity on the functionality of marine ecosystems is crucial for predicting and managing the associated impacts. Coastal ecosystems are important sources of carbon (primary production) to shelf waters and play a vital role in global nutrient cycling. These systems are especially vulnerable to the effects of human activities and will be the first areas impacted by rising sea levels. Within these coastal ecosystems, microalgal assemblages (microphytobenthos: MPB) are vital for autochthonous carbon fixation. The level of in situ production by MPB mediates the net carbon cycling of transitional ecosystems between net heterotrophic or autotrophic metabolism. In this study, we examine the interactive effects of elevated atmospheric CO2 concentrations (370, 600, and 1000 ppmv), temperature (6°C, 12°C, and 18°C) and invertebrate biodiversity on MPB biomass in experimental systems. We assembled communities of three common grazing invertebrates (Hydrobia ulvae, Corophium volutator and Hediste diversicolor) in monoculture and in all possible multispecies combinations. This experimental design specifically addresses interactions between the selected climate change variables and any ecological consequences caused by changes in species composition or richness. Results The effects of elevated CO2 concentration, temperature and invertebrate diversity were not additive, rather they interacted to determine MPB biomass, and overall this effect was negative. Diversity effects were underpinned by strong species composition effects, illustrating the importance of individual species identity. Conclusions Overall, our findings suggest that in natural systems, the complex interactions between changing environmental conditions and any associated changes in invertebrate assemblage structure are likely to reduce MPB biomass. Furthermore, these effects would be

  3. Impact of biodiversity-climate futures on primary production and metabolism in a model benthic estuarine system.

    PubMed

    Hicks, Natalie; Bulling, Mark T; Solan, Martin; Raffaelli, Dave; White, Piran C L; Paterson, David M

    2011-02-14

    Understanding the effects of anthropogenically-driven changes in global temperature, atmospheric carbon dioxide and biodiversity on the functionality of marine ecosystems is crucial for predicting and managing the associated impacts. Coastal ecosystems are important sources of carbon (primary production) to shelf waters and play a vital role in global nutrient cycling. These systems are especially vulnerable to the effects of human activities and will be the first areas impacted by rising sea levels. Within these coastal ecosystems, microalgal assemblages (microphytobenthos: MPB) are vital for autochthonous carbon fixation. The level of in situ production by MPB mediates the net carbon cycling of transitional ecosystems between net heterotrophic or autotrophic metabolism. In this study, we examine the interactive effects of elevated atmospheric CO(2) concentrations (370, 600, and 1000 ppmv), temperature (6°C, 12°C, and 18°C) and invertebrate biodiversity on MPB biomass in experimental systems. We assembled communities of three common grazing invertebrates (Hydrobia ulvae, Corophium volutator and Hediste diversicolor) in monoculture and in all possible multispecies combinations. This experimental design specifically addresses interactions between the selected climate change variables and any ecological consequences caused by changes in species composition or richness. The effects of elevated CO(2) concentration, temperature and invertebrate diversity were not additive, rather they interacted to determine MPB biomass, and overall this effect was negative. Diversity effects were underpinned by strong species composition effects, illustrating the importance of individual species identity. Overall, our findings suggest that in natural systems, the complex interactions between changing environmental conditions and any associated changes in invertebrate assemblage structure are likely to reduce MPB biomass. Furthermore, these effects would be sufficient to affect the

  4. The use of multiple imputation in the Southern Annual Forest Inventory System

    Treesearch

    Gregory A. Reams; Joseph M. McCollum

    2000-01-01

    The Southern Research Station is currently implementing an annual forest survey in 7 of the 13 states that it is responsible for surveying. The Southern Annual Forest Inventory System (SAFIS) sampling design is a systematic sample of five interpenetrating grids, whereby an equal number of plots are measured each year. The area representative and time series nature of...

  5. The use of multiple imputation in the Southern Annual Forest Inventory System

    Treesearch

    Gregory A. Reams; Joseph M. McCollum

    2000-01-01

    The Southern Research Station is currently implementing an annual forest survey in 7 of the 13 States that it is responsible for surveying. The Southern Annual Forest Inventory System (SAFIS) sampling design is a systematic sample of five interpenetrating grids, whereby an equal number of plots are measured each year. The area-representative and time-series...

  6. The encyclopedia of southern Appalachian forest ecosystems: A prototype of an online scientific knowledge management system

    Treesearch

    Deborah K. Kennard; H. Michael Rauscher; Patricia A. Flebbe; Daniel L. Schmoldt; William G. Hubbard; J. Bryan Jordin; William Milnor

    2003-01-01

    The Encyclopedia of Southern Appalachian Forest Ecosystems (ESAFE), a hyperdocument-based encyclopedia system available on the Internet, provides an organized synthesis of existing research on the management and ecology of Southern Appalachian forests ecosystems. The encyclopedia is dynamic, so that new or revised content can be submitted directly through the Internet...

  7. Iodine-131: a potential short-lived, wastewater-specific particle tracer in an urbanized estuarine system.

    PubMed

    Smith, Joseph P; Oktay, Sarah I; Kada, John; Olsen, Curtis R

    2008-08-01

    The short-lived, fission-produced radioisotope, 131I (t1/2 = 8.04 days), was detected in wastewater, surficial sediment, and suspended particulate matter (SPM) samples collected from New York Harbor (NYH) between 2001 and 2002. lodine-131 is used as a radiopharmaceutical for medical imaging, diagnostics, and treatments for conditions of the thyroid. It is introduced into the municipal waste stream by medical facilities and patients and is subsequently released into the estuary via wastewater effluent. Measured 131I activities in surface sediments were correlated with those of 7Be (t1/2 = 53.2 days), a naturally occurring radioisotope that is widely used to quantify particle dynamics, sediment focusing, and short-term sediment deposition and accumulation in aquatic systems. Surficial sediment 131I activities were also compared with measured trace metal (Cu, Pb) and organic carbon (OC(sed)) concentrations which can be linked to wastewater inputs. These preliminary results from NYH introduce 131I as a potentially valuable source-specific, shortlived biogeochemical tracer (timescales < 1 month) for particles, sediments, and wastewater-sourced contaminants in urbanized aquatic systems.

  8. Special Data Collection System Event Report. Southern Sinkiang Province, China 16 February 1977

    DTIC Science & Technology

    1978-03-20

    SPECIAL DATA COLLECTION SYSTEM EVENT REPORT Southern Sinkiang Province, China 16 February 1977 Michael S. Dawkins Alexandria Laboratories Teledyne...fi,PECIAL ,PATA 5 OLLECTION SYSTEM ~ ~~~~ ( ~ Technical rep*~’. J~ ~i~Southern Sinkiang Province , China ~~~~~~~~ -- -——9 ______________ 5...Southern Sinkiang Province, China, (l6 F~~~~ar~~~977 2 This event report contains seismic data~ from the Special Data Collection System (SDCS

  9. Minimal incorporation of Deepwater Horizon oil by estuarine filter feeders.

    PubMed

    Fry, Brian; Anderson, Laurie C

    2014-03-15

    Natural abundance carbon isotope analyses are sensitive tracers for fates and use of oil in aquatic environments. Use of oil carbon in estuarine food webs should lead to isotope values approaching those of oil itself, -27‰ for stable carbon isotopes reflecting oil origins and -1000‰ for carbon-14 reflecting oil age. To test for transfer of oil from the 2010 Deepwater Horizon spill into estuarine food webs, filter-feeding barnacles (Balanus sp.) and marsh mussels (Geukensia demissa) were collected from Louisiana estuaries near the site of the oil spill. Carbon-14 analyses of these animals from open waters and oiled marshes showed that oil use was <1% and near detection limits estimated at 0.3% oil incorporation. Respiration studies showed no evidence for enhanced microbial activity in bay waters. Results are consistent with low dietary impacts of oil for filter feeders and little overall impact on respiration in the productive Louisiana estuarine systems.

  10. Arsenic pollution in Patos Lagoon estuarine sediments, Brazil.

    PubMed

    Mirlean, Nicolai; Andrus, Vlad E; Baisch, Paulo; Griep, Gilberto; Casartelli, Maria R

    2003-11-01

    Arsenic distribution in sediments of the Mirim-Patos lagoonal system is investigated. Deposits of fresh water Mirim Lagoon and those of the fresh water part of the Patos Lagoon contain 2.5 and 7.7 mg kg(-1), respectively, on average of total arsenic. In contrast, estuarine sediments of the Patos Lagoon are evidently contaminated by arsenic in high concentrations (up to 50 mg kg(-1)), and about 80% of the arsenic there is found in a bioavailable form. Analytical data coupled with direct, visual observations of estuarine water contamination by raw phosphorites and fertilizers suggest that the major source of arsenic in the estuarine sediments originated from the fertilizer industry.

  11. Holocene paleoclimate records from a large California estuarine system and its watershed region: linking watershed climate and bay conditions

    NASA Astrophysics Data System (ADS)

    Malamud-Roam, Frances P.; Lynn Ingram, B.; Hughes, Malcolm; Florsheim, Joan L.

    2006-07-01

    The San Francisco Bay-Delta system includes a watershed that covers a large area of California and provides water to two-thirds of the State's population. Climate over the estuary and its watershed in the dry summer months is controlled by the subtropical high which dominates and deflects storms from California. The subtropical high weakens and migrates south as the Aleutian Low strengthens, bringing wet winter storms to the region. Paleoclimatic records from the Bay and its greater watershed, spanning the Holocene, are reviewed here in order to better understand natural variations of precipitation and runoff and the linkages between those variations and the salinity and ecosystems of the estuary. To better understand regional-scale climate patterns, paleoclimate records from coastal California and the Great Basin are also considered. Large fluctuations in climate have occurred during the period of interest, and there is generally good agreement between the paleoclimate records from different regions. Early Holocene climate throughout California was marked by rising temperatures and reduced moisture as seen in fire records from the watershed. This warmth and aridity peaked about 5000-7000 years ago and was followed by a cooling trend, with variable moisture conditions. The Estuary formed relatively rapidly in response to a high rate of sea level rise that dominated the Holocene until about 6000 years ago, and the subsequent reduced rate of inundation allowed vast tidal marshes to form along the edges of the estuary, which have since been recording changes in environmental conditions. The impacts of changing regional climate patterns are experienced in the San Francisco Bay-Delta system, as altered fresh water flows result in altered estuary salinity. For example, approximately 3800 cal yr B.P., records from throughout the state indicate a cool, moist period, and Bay salinity was reduced; this period was followed by a general drying trend throughout California over

  12. Stable carbon and nitrogen isotope composition of aquatic and terrestrial plants of the San Francisco Bay estuarine system

    USGS Publications Warehouse

    Cloern, J.E.; Canuel, E.A.; Harris, D.

    2002-01-01

    We report measurements of seasonal variability in the C-N stable isotope ratios of plants collected across the habitat mosaic of San Francisco Bay, its marshes, and its tributary river system. Analyses of 868 plant samples were binned into 10 groups (e.g., terrestrial riparian, freshwater phytoplankton, salt marsh) to determine whether C-N isotopes can be used as biomarkers for tracing the origins of organic matter in this river-marsh-estuary complex. Variability of ??13C and ??15N was high (???5-10???) within each plant group, and we identified three modes of variability: (1) between species and their microhabitats, (2) over annual cycles of plant growth and senescence, and (3) between living and decomposing biomass. These modes of within-group variability obscure any source-specific isotopic signatures, confounding the application of C-N isotopes for identifying the origins of organic matter. A second confounding factor was large dissimilarity between the ??13C-??15N of primary producers and the organic-matter pools in the seston and sediments. Both confounding factors impede the application of C-N isotopes to reveal the food supply to primary consumers in ecosystems supporting diverse autotrophs and where the isotopic composition of organic matter has been transformed and become distinct from that of its parent plant sources. Our results support the advice of others: variability of C-N stable isotopes within all organic-matter pools is high and must be considered in applications of these isotopes to trace trophic linkages from primary producers to primary consumers. Isotope-based approaches are perhaps most powerful when used to complement other tools, such as molecular biomarkers, bioassays, direct measures of production, and compilations of organic-matter budgets.

  13. Effect of melatonin in the antioxidant defense system in the locomotor muscles of the estuarine crab Neohelice granulata (Decapoda, Brachyura).

    PubMed

    Geihs, Márcio Alberto; Vargas, Marcelo Alves; Maciel, Fábio Everton; Caldas, Sergiane Souza; Cruz, Bruno Pinto; Primel, Ednei Gilberto; Monserrat, José Maria; Nery, Luiz Eduardo Maia

    2010-03-01

    In vertebrates, many studies verified different effects of melatonin in the antioxidant defense system (ADS). In crustaceans, few studies have been conducted to verify this possibility. We verified the melatonin effects in the crab Neohelice granulata using low (0.002 and 0.02 pmol/crab) and high (2.0 and 20.0 pmol/crab) melatonin dosages in short-term (0.5h) and long-term (9.5h) experiments. We analyzed the antioxidant capacity against peroxyl radicals (ACAP), reactive oxygen species (ROS) concentration, levels of by products of lipid peroxidation (LPO), oxygen consumption (VO(2)), the activity of glutamate cysteine ligase (gamma-GCL) and catalase (CAT) and glutathione content (GSH). Finally, the effects of exogenous melatonin were verified in terms of melatonin and N(1)-acetyl-N(2)-formyl-5-methoxykynuramine (AFMK) content in the muscles of N. granulata. In short-term experiment and low dosages, melatonin increased the VO(2), gamma-GCL activity and GSH content (p<0.05) and decreased melatonin content (p<0.05) without effects in ROS, ACAP and LPO (p>0.05). Possibly, melatonin is acting in the ADS increasing its efficiency and/or acting in mitochondrial activity and/or through signaling muscles to increase its consumption. AFMK was only detected in the eyestalk and cerebroid ganglia. In high dosages melatonin effects decreased, possibly by the desensitization of their receptors. In long-term experiment, melatonin decreased ACAP (p<0.05), and CAT activity (p<0.05) in low dosages. In high dosages melatonin reduced VO(2) (p<0.05) and increased ACAP (p<0.05), possibly stimulating others components of the ADS. In conclusion, melatonin in the locomotor muscles of N. granulata affects the antioxidant/pro-oxidant balance in a time and dosage dependent manner. Copyright 2009 Elsevier Inc. All rights reserved.

  14. The robustness of ecological indicators to detect long-term changes in the macrobenthos of estuarine systems.

    PubMed

    Patrício, Joana; Neto, João Magalhães; Teixeira, Heliana; Salas, Fuensanta; Marques, João Carlos

    2009-07-01

    Accurate and reliable benthic quality indicators are in great demand following the recent developments and the strict time schedule for implementing the European Water Framework Directive. The Mondego estuary has experienced a progressive deterioration during the 1990s, followed by a partial ecological recovery due to restoration measures in 1997/1998. We have used the estuary as a model system to test the performance and robustness of a set of ecological indicators in highlighting the changes in the ecological state of intertidal areas. Over a period of 17 years (1985-2002), we calculated Margalef, Shannon-Wiener, Berger-Parker, Taxonomic Distinctness measures, AZTI's Marine Biotic Index, Infaunal Trophic Index, and Eco-Exergy based indices and tested differences across periods characterised by different anthropogenic disturbance. We combined temporal data within three periods: before, during and after disturbance, based on progressive information on the changes in the extended type of anthropogenic disturbance. Indices were then compared with biological and abiotic descriptors (macroalgae, macrophytes, benthic macrofauna, nutrients concentration, sediment grain size and total organic carbon). We found great disparity in the indicators ability to capture temporal changes, showing distinct performances at each site. At the Zostera noltii site, only Margalef, Total Taxonomic Distinctness and the thermodynamically based indices captured temporal changes, despite giving higher values during the disturbance period. At the bare sediment site, Taxonomic Distinctness, ITI, Shannon-Wiener, Berger-Parker, AMBI and the TBI were able to distinguish between periods, in agreement with the differences observed analysing the macrobenthic assemblages. Furthermore, Taxonomic Distinctness was not robust enough to detect any temporal or spatial change. We thus suggest further research to understand the behaviour of ecological indicators, in view of their crucial importance for the

  15. Estuarine 'collaboratories:' regional and global perspectives (Invited)

    NASA Astrophysics Data System (ADS)

    Baptista, A. M.; Needoba, J. A.; Davis, M.; Leinen, M.

    2013-12-01

    There is an urgent need to anticipate and manage environmental changes in estuaries, as these critical ecosystems provide services that are essential for regional and global sustainability. Collaboratively designed and operated estuarine observation and prediction systems are progressively enabling long-term and high-resolution characterizations of estuarine variability and function, thus providing a powerful foundation for stewardship activities. The benefits of these 'collaboratories' have been demonstrated regionally in various estuaries, and their broader scale potential is being explored through an emerging national and international initiative. The first part of this presentation will address the lessons learned from SATURN (http://www.stccmop.org), a mature multi-institutional 'collaboratory' for the Columbia River estuary. SATURN innovatively integrates sensors, models, flows of information, and communities of practice. This integration has fueled advances in understanding and prediction of the estuary as a complex and highly variable bioreactor, subject to shifts from global climate change and from evolving regional uses. Our focus will be on describing the aspects of the design and practice that make SATURN transformative as a scientific and management-support tool at a regional scale. The second part of the presentation will address the translation of lessons learned from and beyond SATURN into requirements for a global network of estuarine observation and prediction systems. 'Our Global Estuary' is an initiative designed to create and use such a network, to maximize the aggregate potential of estuaries as sentinels and key players in global sustainability. We will report on the main recommendations of the first planning workshop for this initiative, which will take place on October 2013.

  16. Remote sensing of estuarine fronts and their effects on pollutants

    NASA Technical Reports Server (NTRS)

    Klemas, V. (Principal Investigator); Polis, D. F.

    1975-01-01

    The author has identified the following significant results. Imagery from LANDSAT 1 and 2 proved valuable in determining the location, type, and extent of estuarine fronts under different tidal conditions. Neither ships nor aircraft alone could provide as complete, synoptic, and repetitive an overview as did the satellites. Since estuarine fronts influence the movement of oil slicks and dispersion of other pollutants, cleanup operations depending on real time use of oil slick movement prediction models will benefit not only from aircraft tracking the actual slicks but also from real time satellite observations of surface currents and the location of frontal systems.

  17. Estuarine Ecology as Project Work.

    ERIC Educational Resources Information Center

    Humphreys, T. J.

    1981-01-01

    Discusses advantages of using an estuarine environment as a study area for A-level students and reviews organizational considerations. Details and references regarding a variety of suitable techniques are provided along with examples of results obtained by students at Waltham Forest College. (Author/DC)

  18. Geodetic Monitoring System Operating On Neapolitan Volcanic Area (southern Italy)

    NASA Astrophysics Data System (ADS)

    Pingue, F.; Ov-Geodesy Team

    The Neapolitan volcanic area is located in the southern sector of the Campanian Plain Graben including three volcanic active structures (Somma-Vesuvius, Campi Flegrei and Ischia). The Somma-Vesuvius complex, placed East of Naples, is a strato-volcano composed by a more ancient apparatus (Mt. Somma) and a younger cone (Mt. Vesu- vius) developed inside Somma caldera. Since last eruption (1944) it is in a quiescent state characterised by a low level seismicity and deformation activity. The Campi Fle- grei, located West of Naples, are a volcanic field inside an older caldera rim. The last eruption, occurred in the 1538, built up the Mt. Nuovo cone. The Campi Flegrei are subject to a slow vertical deformation, called bradyseism. In the 1970-1972 and 1982-1984 they have been affected by two intense episodes of ground upheaval (ac- companied by an intense seismic activity)0, followed by a subsidence phase, slower than uplift and still active. Though such phenomenon has not been followed by erup- tive events, it caused serious damages, emphasizing the high volcanic risk of the phle- grean caldera. The Ischia island, located SW of Naples, has been characterised by a volcanic activity both explosive and effusive, occurred mainly in the last 50,000 years. These events modelled the topography producing fault systems and structures delim- iting the Mt. Epomeo resurgent block. The last eruption has occurred on 1302. After, the dynamics of the island has been characterised by seismic activity (the strongest earthquake occurred on 1883) and by a meaningful subsidence, on the S and NW sec- tors of the island. The concentration of such many active volcanoes in an area with a dense urbanization (about 1,500,000 inhabitants live) needs systematic and contin- uous monitoring of the dynamics. These information are necessary in order to char- acterise eruptive precursors useful for modelling the volcanoes behaviour. Insofar, the entire volcanic Neapolitan area, characterised by a

  19. The National Fire Danger Rating System: Derivation of Spread Index for Eastern and Southern States

    Treesearch

    Ralph M. Nelson

    1964-01-01

    Presents standards for locating, operating, and maintaining forest fire danger stations in Eastern and Southern States. Includes tables and forms for deriving the Spread Index of the new National Fire-Danger Rating System.

  20. Challenging paradigms in estuarine ecology and management

    NASA Astrophysics Data System (ADS)

    Elliott, M.; Whitfield, A. K.

    2011-10-01

    For many years, estuarine science has been the 'poor relation' in aquatic research - freshwater scientists ignored estuaries as they tended to get confused by salt and tides, and marine scientists were more preoccupied by large open systems. Estuaries were merely regarded by each group as either river mouths or sea inlets respectively. For the past four decades, however, estuaries (and other transitional waters) have been regarded as being ecosystems in their own right. Although often not termed as such, this has led to paradigms being generated to summarise estuarine structure and functioning and which relate to both the natural science and management of these systems. This paper defines, details and affirms these paradigms that can be grouped into those covering firstly the science (definitions, scales, linkages, productivity, tolerances and variability) and secondly the management (pressures, valuation, health and services) of estuaries. The more 'science' orientated paradigms incorporate the development and types of ecotones, the nature of stressed and variable systems (with specific reference to resilience and redundancy), the relationship between generalists and specialists produced by environmental tolerance, the relevance of scale in relation to functioning and connectivity, the sources of production and degree of productivity, the biodiversity-ecosystem functioning and the stress-subsidy debates. The more 'management' targeted paradigms include the development and effects of exogenic unmanaged pressures and endogenic managed pressures, the perception of health and the ability to manage estuaries (related to internal and external influences), and the influence of all of these on the production of ecosystem services and societal benefits.

  1. Special Data Collection System (SDCS) Event Report, Southern Sinkiang Province, 27 October 1975

    DTIC Science & Technology

    1976-01-13

    34■ r»" ’www AD~A021 395 SPECIAL DATA COLLECTION SYSTEM (SDCS) EVENT REPORT, SOUTHERN SINKIANG PROVINCE, 27 OCTOBER 1975 K... Sinkiang Province, 27 October 1975 K.J. Hill, M.S. DsMkins, R.R. Baumstark, and M. D. Gillispie Alexandria Laboratories Teledyne Geotech, 314 Montgomery...ACCESSION NO 4 TITLE \\*nrl Suhllllr) SPECIAL DATA COLLECTION SYSTEM (SDCS) £##*? ApMCr Southern Sinkiang Province, 27 October 1975

  2. Resolving drivers of variability in estuarine metabolism from sustained observations of water quality in the SE US

    EPA Science Inventory

    We examine trends in water quality in long-term monitoring (10-15 y) data collected at 5 estuarine systems of NOAA’s National Estuarine Research Reserve System: Grand Bay, MS; Weeks Bay, AL; Apalachicola Bay, FL; Rookery Bay, FL, and Guana Tolomatos and Matanzas Rivers, FL. These...

  3. Resolving drivers of variability in estuarine metabolism from sustained observations of water quality in the SE US

    EPA Science Inventory

    We examine trends in water quality in long-term monitoring (10-15 y) data collected at 5 estuarine systems of NOAA’s National Estuarine Research Reserve System: Grand Bay, MS; Weeks Bay, AL; Apalachicola Bay, FL; Rookery Bay, FL, and Guana Tolomatos and Matanzas Rivers, FL. These...

  4. Microbial Community in the Hydrothermal System at Southern Mariana Trough

    NASA Astrophysics Data System (ADS)

    Kato, S.; Itahashi, S.; Kakegawa, T.; Utsumi, M.; Maruyama, A.; Ishibashi, J.; Marumo, K.; Urabe, T.; Yamagishi, A.

    2004-12-01

    There is unique ecosystem around deep-sea hydrothermal area. Living organisms are supported by chemical free energy provided by the hydrothermal water. The ecosystem is expected to be similar to those in early stage of life history on the earth, when photosynthetic organisms have not emerged. In this study, we have analyzed the microbial diversity in the hydrothermal area at southern Mariana trough. In the "Archaean Park Project" supported by special Coordination Fund, four holes were bored and cased by titanium pipes near hydrothermal vents in the southern Mariana trough in 2004. Hydrothermal fluids were collected from these cased holes and natural vents in this area. Microbial cells were collected by filtering the hydrothermal fluid in situ or in the mother sip. Filters were stored at -80C and used for DNA extraction. Chimneys at this area was also collected and stored at -80C. The filters and chimney samples were crushed and DNA was extracted. DNA samples were used for amplification of 16S rDNA fragments by PCR using archaea specific primers and universal primers. The PCR fragments were cloned and sequenced. These PCR clones of different samples will be compared. We will extend our knowledge about microbiological diversity at Southern Mariana trough to compare the results obtained at other area.

  5. The role of watershed characteristics in estuarine condition: an empirical approach

    Treesearch

    James Latimer; Melissa Hughes; Michael Charpentier; Christine Tilburg

    2016-01-01

    Estuarine condition is a function of the nature of the estuary, ocean, and atmospheric systems, and the upstream watershed. To fully understand and predict how an estuary will respond to drivers and pressures,...

  6. Ecological periodic tables for nekton and benthic macrofaunal community usage of estuarine habitats Slides

    EPA Science Inventory

    Ecological periodic tables for nekton and benthic macrofaunal community usage of estuarine habitats Steven P. Ferraro, U.S. Environmental Protection Agency, Newport, OR Background/Questions/Methods The chemical periodic table, the Linnaean system of classification, and the Her...

  7. Ecological periodic tables for nekton and benthic macrofaunal community usage of estuarine habitats Slides

    EPA Science Inventory

    Ecological periodic tables for nekton and benthic macrofaunal community usage of estuarine habitats Steven P. Ferraro, U.S. Environmental Protection Agency, Newport, OR Background/Questions/Methods The chemical periodic table, the Linnaean system of classification, and the Her...

  8. 17. 'Southern Pacific Company Pacific System, 3 180'61/2' ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    17. 'Southern Pacific Company - Pacific System, 3 - 180'-6-1/2' c. to c. end pins S. Tr. Thro. Spans, 10th, 11th and 13th Crossings of Sacramento River, also for 1 - 180'-6-1/2' c. to c. end pins S. Tr. Thro. Span, 8th Crossing Sacramento River, The Phoenixville Bridge Co., Phoenixville Pa., Apr. 9th, 1901.' - Southern Pacific Railroad Shasta Route, Bridge No. 310.58, Milepost 310.58, Sims, Shasta County, CA

  9. Harvesting systems and costs for southern pine in the 1980s

    Treesearch

    Frederick W. Cubbage; James E. Granskog

    1981-01-01

    Timber harvesting systems and their costs are a major concern for the forest products industries. In this paper, harvest costs per cord are estimated, using computer simulation, for current southern pine harvesting systems. The estimations represent a range of mechanization levels. The sensitivity of systems to factors affecting harvest costs - machine costs, fuel...

  10. Fluvio-estuarine sedimentation and estuarine evolution during the Late-Holocene in the Taw Estuary, England: response to relative sea-level and climate change

    NASA Astrophysics Data System (ADS)

    Havelock, G. M.; Brown, T. G.

    2010-12-01

    Present models of Holocene estuary evolution are driven largely by changes in relative sea-level (RSL) with little reference to long-term changes in fluvial regime and regional climate. Centennial-scale climate change has been shown to have a major control on Holocene river behaviour, with fluvial records showing evidence for a high sensitivity of flood occurrence to changing climate. It follows that the changes in river discharge associated with these climatic fluctuations should have an important bearing on inner estuarine hydrology and sedimentology. Indeed, recent US studies have shown that changes in freshwater inflow can be inferred by changes in estuarine paleosalinity and that the timing of these events reflect changes in regional precipitation. Deposition in the transitional inner estuarine environment can therefore be seen to be controlled by both marine and fluvial influences. The fluvio-estuarine late-Holocene sedimentary record was investigated in the macro-tidal Taw Estuary, south-west England in order to ascertain the relative importance of changes in RSL and precipitation driven river discharge on estuarine sedimentation and centennial-scale geomorphic evolution. The inner estuarine record was compared with a local RSL reconstruction for the Taw Estuary and with a reconstructed Holocene flood record and geomorphic fluvial history for the lower Taw valley. The diatom record of numerous sediment cores enabled paleosalinity to be evaluated. The fluvio-estuarine valley fill was split into a series of stratigraphic units, with a chronological framework derived using radiocarbon and OSL dating methods. Geomorphic change in the inner estuarine zone is shown to be mainly influenced by phases of increased river discharge and catchment precipitation, with fluvial instability translating down river into the inner estuarine system. This results in periods of enhanced tidal channel migration, marsh-floodplain formation and estuarine channel-bed aggradation

  11. Succession Planning for the 1862 Institutions in the Southern Region States of the Cooperative Extension System

    ERIC Educational Resources Information Center

    Kelly, Tammy Denise

    2015-01-01

    The purpose of this study was to explore and describe succession plans and components of importance as perceived by the organizational leadership within the Southern Region of the Cooperative Extension System. Cooperative Extension Systems across the United States, continue to be faced with a reduction in force, primarily due to retirement, budget…

  12. New Tree-Classification System Used by the Southern Forest Inventory and Analysis Unit

    Treesearch

    Dennis M. May; John S. Vissage; D. Vince Few

    1990-01-01

    Trees at USDA Forest Service, Southern Forest Inventory and Analysis, sample locations are classified as growing stock or cull based on their ability to produce sawlogs. The old and new classification systems are compared, and the impacts of the new system on the reporting of tree volumes are illustrated with inventory data from north Alabama.

  13. Southern California Alluvial Basins Regional Aquifer-Systems analysis; a bibliography

    USGS Publications Warehouse

    Moyle, W.R.; Martin, Peter; Schluter, R.C.; Woolfenden, L.R.; Downing, Karen; Elliott, A.L.; Maltby, D.E.

    1986-01-01

    A bibliography for the Southern California Alluvial Basins Regional Aquifer-Systems Analysis includes references for about 3,500 publications related to the geohydrology of the 75,000 sq-mi region, which encompasses all of southern California except the Central Valley, the Channel Islands and the Pacific Ocean floor off southern California, and parts of adjacent states and Mexico. The report indexes the publications in six geographic categories and induces a list of sources of publications. Because of the large number of references in the bibliography, a system was developed for computer storage and retrieval. References can be retrieved by geographic location, author, or geohydrologic discipline and subject. The computer system allows for updating and addition of references. (USGS)

  14. Foraging ecology of sanderlings Calidris alba wintering in estuarine and non-estuarine intertidal areas

    NASA Astrophysics Data System (ADS)

    Lourenço, Pedro M.; Alves, José A.; Catry, Teresa; Granadeiro, José P.

    2015-10-01

    Outside the breeding season, most shorebirds use either estuarine or non-estuarine intertidal areas as foraging grounds. The sanderling Calidris alba is mostly associated with coastal sandy beaches, a habitat which is currently at risk worldwide due to increasing coastal erosion, but may also use estuarine sites as alternative foraging areas. We aimed to compare the trophic conditions for sanderlings wintering in estuarine and non-estuarine sites within and around the Tejo estuary, Portugal, where these two alternative wintering options are available within a relatively small spatial scale. To achieve this, we analysed sanderling diet, prey availability, foraging behaviour, and time and energy budgets in the different substrates available in estuarine and non-estuarine sites. In terms of biomass, the most important sanderling prey in the estuarine sites were siphons of the bivalve Scrobicularia plana, polychaetes, staphylinids and the gastropod Hydrobia ulvae. In non-estuarine sites the main prey were polychaetes, the bivalve Donax trunculus and chironomid larvae. Both food availability and energetic intake rates were higher on estuarine sites, and sanderlings spent a higher proportion of time foraging on non-estuarine sites. In the estuary, sanderlings foraged in muddy-sand substrate whenever it was available, achieving higher intake rates than in sandy substrates. In the non-estuarine sites they used both sandy and rocky substrates throughout the tidal cycle but had higher intakes rates in sandy substrate. Estuarine sites seem to offer better foraging conditions for wintering sanderlings than non-estuarine sites. However, sanderlings only use muddy-sand and sandy substrates, which represent a small proportion of the intertidal area of the estuary. The extent of these substrates and the current sanderling density in the estuary suggest it is unlikely that the estuary could provide alternative wintering habitat for sanderlings if they face habitat loss and

  15. Southern RS CVn systems - Candidate list. [spectral catalog of variable binary stars

    NASA Technical Reports Server (NTRS)

    Weiler, E. J.; Stencel, R. E.

    1979-01-01

    A list of 43 candidate RS CVn binary systems in the far southern hemisphere of the sky (south of -40 deg declination) is presented. The candidate systems were selected from the first two volumes of the Michigan Spectral Catalog (1975, 1978), which provides MK classifications for southern HD stars and identifies any unusual characteristics noted for individual stellar spectra. The selection criteria used were: (1) the occurrence of Ca II H and K emission; (2) known or suspected binary nature; (3) regular light variations of zero to one magnitude; and (4) spectral type between F0 and K2 and luminosity less than bright giant (II).

  16. Southern RS CVn systems - Candidate list. [spectral catalog of variable binary stars

    NASA Technical Reports Server (NTRS)

    Weiler, E. J.; Stencel, R. E.

    1979-01-01

    A list of 43 candidate RS CVn binary systems in the far southern hemisphere of the sky (south of -40 deg declination) is presented. The candidate systems were selected from the first two volumes of the Michigan Spectral Catalog (1975, 1978), which provides MK classifications for southern HD stars and identifies any unusual characteristics noted for individual stellar spectra. The selection criteria used were: (1) the occurrence of Ca II H and K emission; (2) known or suspected binary nature; (3) regular light variations of zero to one magnitude; and (4) spectral type between F0 and K2 and luminosity less than bright giant (II).

  17. Aqueous geochemistry of the Thermopolis hydrothermal system, southern Bighorn Basin, Wyoming, U.S.A.

    SciTech Connect

    Kaszuba, John P.; Sims, Kenneth W.W.; Pluda, Allison R.

    2014-06-01

    The Thermopolis hydrothermal system is located in the southern portion of the Bighorn Basin, in and around the town of Thermopolis, Wyoming. It is the largest hydrothermal system in Wyoming outside of Yellowstone National Park. The system includes hot springs, travertine deposits, and thermal wells; published models for the hydrothermal system propose the Owl Creek Mountains as the recharge zone, simple conductive heating at depth, and resurfacing of thermal waters up the Thermopolis Anticline.

  18. Aqueous geochemistry of the Thermopolis hydrothermal system, southern Bighorn Basin, Wyoming, U.S.A.

    DOE PAGES

    Kaszuba, John P.; Sims, Kenneth W.W.; Pluda, Allison R.

    2014-06-01

    The Thermopolis hydrothermal system is located in the southern portion of the Bighorn Basin, in and around the town of Thermopolis, Wyoming. It is the largest hydrothermal system in Wyoming outside of Yellowstone National Park. The system includes hot springs, travertine deposits, and thermal wells; published models for the hydrothermal system propose the Owl Creek Mountains as the recharge zone, simple conductive heating at depth, and resurfacing of thermal waters up the Thermopolis Anticline.

  19. Hexabromocyclododecane (HBCD) and tetrabromobisphenol A (TBBPA) in riverine and estuarine sediments of the Pearl River Delta in southern China, with emphasis on spatial variability in diastereoisomer- and enantiomer-specific distribution of HBCD.

    PubMed

    Feng, An-Hong; Chen, She-Jun; Chen, Man-Ying; He, Ming-Jing; Luo, Xiao-Jun; Mai, Bi-Xian

    2012-05-01

    Hexabromocyclododecane (HBCD) and tetrabromobisphenol A (TBBPA) were measured in surface sediments in the Pearl River Delta, southern China. The concentrations ranged from 0.06 to 304 ng/g dry weight for TBBPA and from 0.03 to 31.6 ng/g for total HBCD. The correlations between the TBBPA and HBCD concentrations were significant in rivers (Dongjiang, Zhujiang, Beijiang, and Dayanhe Rivers) with local input sources but not significant in the Xijiang River and Pearl River Estuary without local sources. HBCD was dominated by γ-HBCD (averaged 52.5-75.0%), whereas α-HBCD contributions were relatively high in sediments from the urban areas. The enantiomeric fractions of γ-HBCD in the sediments (averaged from 0.431 ± 0.035 to 0.479 ± 0.010) differed significantly from that in HBCD technical product except for samples from the e-waste area (Dayanhe River, 0.488 ± 0.091). This suggests that enantioselective biotransformation of HBCD occurs in the aquatic environment in this region.

  20. Simulation modeling of estuarine ecosystems

    NASA Technical Reports Server (NTRS)

    Johnson, R. W.

    1980-01-01

    A simulation model has been developed of Galveston Bay, Texas ecosystem. Secondary productivity measured by harvestable species (such as shrimp and fish) is evaluated in terms of man-related and controllable factors, such as quantity and quality of inlet fresh-water and pollutants. This simulation model used information from an existing physical parameters model as well as pertinent biological measurements obtained by conventional sampling techniques. Predicted results from the model compared favorably with those from comparable investigations. In addition, this paper will discuss remotely sensed and conventional measurements in the framework of prospective models that may be used to study estuarine processes and ecosystem productivity.

  1. Anatomy of La Jolla submarine canyon system; offshore southern California

    USGS Publications Warehouse

    Paull, C.K.; Caress, D.W.; Lundsten, E.; Gwiazda, R.; Anderson, K.; McGann, M.; Conrad, J.; Edwards, B.; Sumner, E.J.

    2013-01-01

    An autonomous underwater vehicle (AUV) carrying a multibeam sonar and a chirp profiler was used to map sections of the seafloor within the La Jolla Canyon, offshore southern California, at sub-meter scales. Close-up observations and sampling were conducted during remotely operated vehicle (ROV) dives. Minisparker seismic-reflection profiles from a surface ship help to define the overall geometry of the La Jolla Canyon especially with respect to the pre-canyon host sediments. The floor of the axial channel is covered with unconsolidated sand similar to the sand on the shelf near the canyon head, lacks outcrops of the pre-canyon host strata, has an almost constant slope of 1.0° and is covered with trains of crescent shaped bedforms. The presence of modern plant material entombed within these sands confirms that the axial channel is presently active. The sand on the canyon floor liquefied during vibracore collection and flowed downslope, illustrating that the sediment filling the channel can easily fail even on this gentle slope. Data from the canyon walls help constrain the age of the canyon and extent of incision. Horizontal beds of moderately cohesive fine-grained sediments exposed on the steep canyon walls are consistently less than 1.232 million years old. The lateral continuity of seismic reflectors in minisparker profiles indicate that pre-canyon host strata extend uninterrupted from outside the canyon underneath some terraces within the canyon. Evidence of abandoned channels and point bar-like deposits are noticeably absent on the inside bend of channel meanders and in the subsurface of the terraces. While vibracores from the surface of terraces contain thin (< 10 cm) turbidites, they are inferred to be part of a veneer of recent sediment covering pre-canyon host sediments that underpin the terraces. The combined use of state of the art seafloor mapping and exploration tools provides a uniquely detailed view of the morphology within an active submarine canyon.

  2. Upper Basalt-Confined Aquifer System in the Southern Hanford Site

    SciTech Connect

    Thorne, P.

    1999-01-04

    The 1990 DOE Tiger Team Finding GW/CF-202 found that the hydrogeologic regime at the Hanford Site was inadequately characterized. This finding also identified the need for completing a study of the confined aquifer in the central and southern portions of the Hanford Site. The southern portion of the site is of particular interest because hydraulic-head patterns in the upper basalt-confined aquifer system indicate that groundwater from the Hanford central plateau area, where contaminants have been found in the aquifer, flows southeast toward the southern site boundary. This results in a potential for offsite migration of contaminants through the upper basalt-confined aquifer system. Based on the review presented in this report, available hydrogeologic characterization information for the upper basalt-confined aquifer system in this area is considered adequate to close the action item. Recently drilled offsite wells have provided additional information on the structure of the aquifer system in and near the southern part of the Hanford Site. Information on hydraulic properties, hydrochemistry, hydraulic heads and flow directions for the upper basalt-confined aquifer system has been re-examined and compiled in recent reports including Spane and Raymond (1993), Spane and Vermeul ( 1994), and Spane and Webber (1995).

  3. Strategic adaptation of nitrogen management for el nino southern oscillation-induced winter wheat system

    USDA-ARS?s Scientific Manuscript database

    The rainfall anomaly (RA) associated with El Niño-Southern Oscillation (ENSO) has various unwanted impacts on agricultural system globally. The loss of inorganic nitrogen (N) depending on extreme wet or dry conditions is a major concern. The main objective of this study was to adapt site-specific N ...

  4. Variations in Reading Achievement across 14 Southern African School Systems: Which Factors Matter?

    ERIC Educational Resources Information Center

    Hungi, Njora; Thuku, Florence W.

    2010-01-01

    In this study the authors employed a multilevel analysis procedure in order to examine the pupil and school levels factors that contributed to variation in reading achievement among Grade 6 primary school pupils in 14 southern African school systems (Botswana, Kenya, Lesotho, Malawi, Mauritius, Mozambique, Namibia, Seychelles, South Africa,…

  5. Variations in Reading Achievement across 14 Southern African School Systems: Which Factors Matter?

    ERIC Educational Resources Information Center

    Hungi, Njora; Thuku, Florence W.

    2010-01-01

    In this study the authors employed a multilevel analysis procedure in order to examine the pupil and school levels factors that contributed to variation in reading achievement among Grade 6 primary school pupils in 14 southern African school systems (Botswana, Kenya, Lesotho, Malawi, Mauritius, Mozambique, Namibia, Seychelles, South Africa,…

  6. Multilingualism(s) and System-Wide Assessment: A Southern Perspective

    ERIC Educational Resources Information Center

    Heugh, Kathleen; Prinsloo, Cas; Makgamatha, Matthews; Diedericks, Gerda; Winnaar, Lolita

    2017-01-01

    Rapidly changing demographics challenge education systems everywhere. Multilingualism, in particular, brings challenges in curriculum, pedagogy and assessment. Here we draw attention to contexts and practices of multilingual education in southern settings that differ from those in northern ones. Whereas much of the literature indicates that…

  7. Downwelling wind, tides, and estuarine plume dynamics

    NASA Astrophysics Data System (ADS)

    Lai, Zhigang; Ma, Ronghua; Huang, Mingfen; Chen, Changsheng; Chen, Yong; Xie, Congbin; Beardsley, Robert C.

    2016-06-01

    The estuarine plume dynamics under a downwelling-favorable wind condition were examined in the windy dry season of the Pearl River Estuary (PRE) using the PRE primitive-equation Finite-Volume Community Ocean Model (FVCOM). The wind and tide-driven estuarine circulation had a significant influence on the plume dynamics on both local and remote scales. Specifically, the local effect of downwelling-favorable winds on the plume was similar to the theoretical descriptions of coastal plumes, narrowing the plume width, and setting up a vertically uniform downstream current at the plume edge. Tides tended to reduce these plume responses through local turbulent mixing and advection from upstream regions, resulting in an adjustment of the isohalines in the plume and a weakening of the vertically uniform downstream current. The remote effect of downwelling-favorable winds on the plume was due to the wind-induced estuarine sea surface height (SSH), which strengthened the estuarine circulation and enhanced the plume transport accordingly. Associated with these processes, tide-induced mixing tended to weaken the SSH gradient and thus the estuarine circulation over a remote influence scale. Overall, the typical features of downwelling-favorable wind-driven estuarine plumes revealed in this study enhanced our understanding of the estuarine plume dynamics under downwelling-favorable wind conditions.

  8. The impact of electric vehicles on the Southern California Edison System

    SciTech Connect

    Ford, A.

    1992-07-01

    This report describes the results of the first phase of an investigation of the impacts of electric vehicles (EVs) in southern California. The investigation focuses on the Southern California Edison Company (SCE) which provides electric service for approximately 60% of southern California. The project is supported by the Air Quality Impacts of Energy Efficiency'' Program of the California Institute for Energy Efficiency (CIEE). The first phase of the research is organized around how EVs might be viewed by customers, vehicle manufacturers and electric utility companies. The vehicle manufacturers' view has been studied with special emphasis on the role of marketable permit systems. The utilities' view of EVs is the subject of this report. The review is particularly important as several case studies of EVs in southern California have been conducted in recent years. The dynamics of a growing population of EVs is explained. Chapter 5 explains a simple method of deriving the electricity demands which could result from the operation of EVs in southern California. The method is demonstrated for several simple examples and then used to find the demands associated with each of the eight EV scenarios. Chapter 6 reports the impacts on SCE operations from the new demands for electricity. Impacts are summarized in terms of system operating costs, reliability of service, and changes in the utility's average electric rate. Chapter 7 turns to the emissions of air pollutants released by the operation of EVs, conventional vehicles (CVs) and power plants. Chapter 8 takes the air pollution analysis one step further by examining the possible reduction in ambient ozone concentration in southern California.

  9. The impact of electric vehicles on the Southern California Edison System. Final report

    SciTech Connect

    Ford, A.

    1992-07-01

    This report describes the results of the first phase of an investigation of the impacts of electric vehicles (EVs) in southern California. The investigation focuses on the Southern California Edison Company (SCE) which provides electric service for approximately 60% of southern California. The project is supported by the ``Air Quality Impacts of Energy Efficiency`` Program of the California Institute for Energy Efficiency (CIEE). The first phase of the research is organized around how EVs might be viewed by customers, vehicle manufacturers and electric utility companies. The vehicle manufacturers` view has been studied with special emphasis on the role of marketable permit systems. The utilities` view of EVs is the subject of this report. The review is particularly important as several case studies of EVs in southern California have been conducted in recent years. The dynamics of a growing population of EVs is explained. Chapter 5 explains a simple method of deriving the electricity demands which could result from the operation of EVs in southern California. The method is demonstrated for several simple examples and then used to find the demands associated with each of the eight EV scenarios. Chapter 6 reports the impacts on SCE operations from the new demands for electricity. Impacts are summarized in terms of system operating costs, reliability of service, and changes in the utility`s average electric rate. Chapter 7 turns to the emissions of air pollutants released by the operation of EVs, conventional vehicles (CVs) and power plants. Chapter 8 takes the air pollution analysis one step further by examining the possible reduction in ambient ozone concentration in southern California.

  10. Pathobiology of marine and estuarine organisms

    SciTech Connect

    Couch, J.A.; Fournie, J.W.

    1992-12-01

    The book is an up-to-date compendium of scientific findings related to diseases of marine and estuarine organisms. The information was presented at the Gulf Breeze Symposium on Marine and Estuarine Disease Research sponsored by the U.S. Environmental Protection Agency (EPA) Environmental Monitoring and Assessment Program (EMAP) held in October 1990 on Pensacola Beach, Florida. Authors review the state-of-the-science and recommend research for future studies of the impact of xenobiotics and other anthropogenic stress factors on disease processes in marine and estuarine organisms.

  11. Methylmercury production in estuarine sediments: role of organic matter

    PubMed Central

    Schartup, Amina T.; Mason, Robert P.; Balcom, Prentiss H.; Hollweg, Terill A.; Chen, Celia Y.

    2013-01-01

    Methylmercury (MeHg) affects wildlife and human health mainly through marine fish consumption. In marine systems, MeHg is formed from inorganic mercury (HgII) species primarily in sediments then accumulates and biomagnifies in the food web. Most of the fish consumed in the US are from estuarine and marine systems highlighting the importance of understanding MeHg formation in these productive regions. Sediment organic matter has been shown to limit mercury methylation in estuarine ecosystems, as a result it is often described as the primary control over MeHg production. In this paper, we explore the role of organic matter by looking at the effects of its changing sediment concentrations on the methylation rates across multiple estuaries. We measured sedimentary MeHg production at eleven estuarine sites that were selected for their contrasting biogeochemical characteristics, mercury (Hg) content, and location in the Northeastern US (ME, NH, CT, NY, and NJ). Sedimentary total Hg concentrations ranged across five orders of magnitude, increasing in concentration from the pristine, sandy sediments of Wells (ME), to industrially contaminated areas like Portsmouth (NH) and Hackensack (NJ). We find that methylation rates are the highest at locations with high Hg content (relative to carbon), and that organic matter does not hinder mercury methylation in estuaries. PMID:23194318

  12. Rapid climatic signal propagation from source to sink in a southern California sediment-routing system

    USGS Publications Warehouse

    Covault, J.A.; Romans, B.W.; Fildani, A.; McGann, M.; Graham, S.A.

    2010-01-01

    Terrestrial source areas are linked to deep-sea basins by sediment-routing systems, which only recently have been studied with a holistic approach focused on terrestrial and submarine components and their interactions. Here we compare an extensive piston-core and radiocarbon-age data set from offshore southern California to contemporaneous Holocene climate proxies in order to test the hypothesis that climatic signals are rapidly propagated from source to sink in a spatially restricted sediment-routing system that includes the Santa Ana River drainage basin and the Newport deep-sea depositional system. Sediment cores demonstrate that variability in rates of Holocene deep-sea turbidite deposition is related to complex ocean-atmosphere interactions, including enhanced magnitude and frequency of the North American monsoon and El Ni??o-Southern Oscillation cycles, which increased precipitation and fluvial discharge in southern California. This relationship is evident because, unlike many sediment-routing systems, the Newport submarine canyon-and-channel system was consistently linked tothe Santa Ana River,which maintained sediment delivery even during Holocene marine transgression and highstand. Results of this study demonstrate the efficiency of sediment transport and delivery through a spatially restricted, consistently linked routing system and the potential utility of deep-sea turbidite depositional trends as paleoclimate proxies in such settings. ?? 2010 by The University of Chicago.

  13. The European Southern Observatory-MIDAS table file system

    NASA Technical Reports Server (NTRS)

    Peron, M.; Grosbol, P.

    1992-01-01

    The new and substantially upgraded version of the Table File System in MIDAS is presented as a scientific database system. MIDAS applications for performing database operations on tables are discussed, for instance, the exchange of the data to and from the TFS, the selection of objects, the uncertainty joins across tables, and the graphical representation of data. This upgraded version of the TFS is a full implementation of the binary table extension of the FITS format; in addition, it also supports arrays of strings. Different storage strategies for optimal access of very large data sets are implemented and are addressed in detail. As a simple relational database, the TFS may be used for the management of personal data files. This opens the way to intelligent pipeline processing of large amounts of data. One of the key features of the Table File System is to provide also an extensive set of tools for the analysis of the final results of a reduction process. Column operations using standard and special mathematical functions as well as statistical distributions can be carried out; commands for linear regression and model fitting using nonlinear least square methods and user-defined functions are available. Finally, statistical tests of hypothesis and multivariate methods can also operate on tables.

  14. Ecohydraulics and Estuarine Wetland Rehabilitation

    NASA Astrophysics Data System (ADS)

    Rodriguez, J. F.; Howe, A.; Saintilan, N.; Spencer, J.

    2004-12-01

    The hydraulics or water flow in wetlands is known to be a key factor influencing ecosystem development in estuarine wetland environments. The relationship is indirect, with the hydraulics of wetlands influencing a host of factors including soil salinity, waterlogging, sediment transport, sediment chemistry, vegetation dispersal and growth and nutrient availability and cycling. The relationship is also not one way, with the hydraulics of wetlands being influenced by plant and animal activity. Understanding these complex interactions is fundamental for the adequate management of estuarine wetlands. Listed as a Wetland of International Importance under the 1971 Ramsar Convention, the Hunter River estuary is regarded as the most significant site for migratory shorebirds in New South Wales, Australia. Over the past 20 years, the number of migratory shorebirds in the estuary has sharply declined from 8,000 to 4,000 approx. Alteration of bird habitat is believed to be one of the reasons for this alarming trend. In 2004 we started a three-year program to investigate the links between hydraulics, sediment, benthic invertebrates, vegetation and migratory shorebird habitat in the estuary. During the first year we have focused on a highly disturbed part of the Hunter estuary wetlands located on Ash Island. The area is one of the major roosting sites in the estuary and is characterized by a complex hydraulic regime due to a restricted tidal interchange with the Hunter River and the presence of infrastructure for the maintenance of power lines (i.e., roads, bridges, culverts). Salt marshes, mudflat and mangroves are the dominant vegetation types. The monitoring program includes measurements of water levels, salinity, discharge, velocity, turbulence, sediment transport and deposition, plant species and density, soil composition and benthic invertebrates coordinated with observations of bird habitat utilization on a number of locations throughout the wetland and for different flow

  15. Osmoregulation of the resident estuarine fish Atherinella brasiliensis was still affected by an oil spill (Vicuña tanker, Paranaguá Bay, Brazil), 7 months after the accident.

    PubMed

    Souza-Bastos, Luciana R; Freire, Carolina A

    2011-03-01

    An oil tanker loaded with methanol and bunker oil has exploded in November 2004 in Paranaguá Bay, in front of Paranaguá Harbor, southern Brazil. In order to investigate the chronic effects of an oil spill on a resident estuarine fish, the Brazilian silverside Atherinella brasiliensis was sampled 1, 4, and 7 months after the spill, from 2 sites inside Paranaguá Bay, and also from a reference site inside nearby Guaratuba Bay, non-affected by the spill. Increases in plasma osmolality (reaching ~525 mOsm/kg H₂O, or ~70% above values in reference fish) and chloride (reaching 214 mM in site C, or ~51% above values in reference fish) were detected 4 months after the spill, in parallel with branchial carbonic anhydrase inhibition (to 56% of the activity measured in reference fish) in silversides obtained from the contaminated sites. Plasma cortisol concentration increased progressively in samples from fish obtained 4 (462 ng/mL) and 7 (564-650 ng/mL) months after the spill, when compared to values in reference fish (192 ng/mL). Osmoregulation of a resident estuarine fish is still affected by an oil spill, months after the accident. It is, thus, a sensitive tool for the evaluation of the chronic effects of oil spills inside tropical estuarine systems, and A. brasiliensis is proposed as an adequate sentinel species for monitoring protocols.

  16. Surveying of morphological variations in estuarine Nyband River

    NASA Astrophysics Data System (ADS)

    Ghobadi-Bistooni, S.; Ershadi, C.

    2009-04-01

    Rivers estuary in aspect of ecological and morphological is very sensitive in coastal zones. This area can affect from human activities and these activities have direct effective on natural state of these area. There for, overall aim of this work is steady on development of this coastal area and thus, it is investigated the morphological and sedimentation mechanism in estuarine area. For this case study, area is limited (27°11'NL ; 56°19'EL), begin from Genu mountains in southern parts of Iran and pass from mid of Bandar Abbas city and in final ends to north of Persian Gulf. There were some physical variations in this estuarine area of Nyband River due to human activities. These variations include: fixing the banks, Jetty break water in near of estuary and recently sealing the bed bottom of river and building of bridge. A numerical program was used for analysis this hydrodynamic and sediment condition. This result compares with field data for evaluation of the numerical analysis. Also, the aero photographical document in past decade was prepared for surveying morphological variations. For this purpose, the GIS (ARCVIEW) was used and finally, the effect of the human activities, such as building of new structure, on morphology of river was investigated.

  17. Warning system for hydrogeological hazards in Campania (Southern Italy)

    NASA Astrophysics Data System (ADS)

    Biafore, Mauro; Cristiano, Luigi; Gentile, Salvatore; Gentilella, Matteo; Giannattasio, Maurizio; Napoli, Francesca

    2010-05-01

    Campania is the Italian region with the highest population density (419 inhabitants/km2). Almost 20% of its territory (13669 km2) is affected by significant hydrogeological hazards, with related loss scenarios in almost 12% of it. The most critical hydrogeological hazard scenarios are those triggered by extreme rainfall events with duration ranging from a few tens of minutes up 72 hours: flood loss scenarios are expected in catchments with spatial extent from a few Km2 up to 5000 km2; shallow landslides and mudflows are also triggered by rainfall events within a broad range of time scales. This study presents a warning system for hydrogeological hazards, which has been operating in Campania since 2005, designed for mitigating losses due to extreme rainfall events. The warning system is structured into two stages: the meteorological forecasting stage and the hydrological monitoring stage. In the first stage, after evaluating rainfall forecasts provided by numerical weather prediction models (with a forecasting time up to 48 hours), warning messages are issued to the local municipalities grouped in 8 warning zones. Critical rainfall events are identified by three different alert levels, according to their forecasted spatial and temporal extents, each corresponding to a category of expected hazard scenarios at regional level. During the second stage, the dynamic evolution of the hydrological events is monitored by a real-time network of river stage and rain gauges, which are employed to compute one or more precursors for each loss scenario. Loss scenarios have been classified according to the temporal and spatial scales of the corresponding precursors, in order to deal with the difficulties related to the occurrence of significantly different hazard scenarios during the same rainfall event. Three threshold values have been identified for each precursor, corresponding to given hazard and alert levels. As a precursor exceeds a threshold value, warning messages are

  18. Floristic evolution in an agroforestry system cultivation in Southern Brazil.

    PubMed

    Silva, Luís C R; Machado, Sebastião A; Galvão, Franklin; Figueiredo, Afonso

    2016-06-07

    Bracatinga (Mimosa scabrella Bentham) is an important pioneer tree species in Ombrophylous Mixed Forest of Brazil and is widely used as an energy source. In traditional agroforestry systems, regeneration is induced by fire, then pure and dense stands known as bracatinga stands (bracatingais) are formed. In the first year, annual crops are intercalated with the seedlings. At that time the seedlings are thinned, then the stands remain at a fallow period and cut at seven years old. The species is very important mainly for small landowners. We studied the understory species that occur naturally during the succession over several years in order to manage them rationally in the future and maintain the natural vegetation over time. Three to 20 year-old Bracatinga stands were sampled between 1998 and 2011. All tree species with diameter at breast height (DBH) ≥ 5 cm were measured.The floristic evolution was assessed with respect to Sociability Index, the Shannon Diversity Index and the Pielou Evenness Index. Graphs of rank/abundance over different age groups were evaluated using the Kolmogorov-Smirnov test. We identified 153 species dispersed throughout the understory and tend to become aggregated over time.

  19. Managing bay and estuarine ecosystems for multiple services

    USGS Publications Warehouse

    Needles, Lisa A.; Lester, Sarah E.; Ambrose, Richard; Andren, Anders; Beyeler, Marc; Connor, Michael S.; Eckman, James E.; Costa-Pierce, Barry A.; Gaines, Steven D.; Lafferty, Kevin D.; Lenihan, Junter S.; Parrish, Julia; Peterson, Mark S.; Scaroni, Amy E.; Weis, Judith S.; Wendt, Dean E.

    2013-01-01

    Managers are moving from a model of managing individual sectors, human activities, or ecosystem services to an ecosystem-based management (EBM) approach which attempts to balance the range of services provided by ecosystems. Applying EBM is often difficult due to inherent tradeoffs in managing for different services. This challenge particularly holds for estuarine systems, which have been heavily altered in most regions and are often subject to intense management interventions. Estuarine managers can often choose among a range of management tactics to enhance a particular service; although some management actions will result in strong tradeoffs, others may enhance multiple services simultaneously. Management of estuarine ecosystems could be improved by distinguishing between optimal management actions for enhancing multiple services and those that have severe tradeoffs. This requires a framework that evaluates tradeoff scenarios and identifies management actions likely to benefit multiple services. We created a management action-services matrix as a first step towards assessing tradeoffs and providing managers with a decision support tool. We found that management actions that restored or enhanced natural vegetation (e.g., salt marsh and mangroves) and some shellfish (particularly oysters and oyster reef habitat) benefited multiple services. In contrast, management actions such as desalination, salt pond creation, sand mining, and large container shipping had large net negative effects on several of the other services considered in the matrix. Our framework provides resource managers a simple way to inform EBM decisions and can also be used as a first step in more sophisticated approaches that model service delivery.

  20. Histopathological lesions and DNA adducts in the liver of European flounder (Platichthys flesus) collected in the Seine estuary versus two reference estuarine systems on the French Atlantic coast.

    PubMed

    Cachot, Jérôme; Cherel, Yan; Larcher, Thibaut; Pfohl-Leszkowicz, Annie; Laroche, Jean; Quiniou, Louis; Morin, Jocelyne; Schmitz, Julien; Burgeot, Thierry; Pottier, Didier

    2013-02-01

    . Flounders from the Bay of Veys had relatively few liver lesions as compared to flounders from the two other estuaries. Flounders from the Ster estuary exhibited the highest prevalence of parasites (37.2 %) and inflammations (51.1 %). Finally, FCA and liver tumors occurred at very similar levels in both flounder populations from the Seine and the Ster estuaries. Group 0 flounders inhabiting the upper Seine estuary were more prone to parasitic and pre-neoplastic hepatic lesions and had higher levels of liver DNA adducts than the older ones living downstream. It was postulated that group 0 European flounders may serve as valuable bioindicators for assessing the quality of estuarine waters and the health status of euryhaline fish populations.

  1. Epibenthic amphipod abundance and predation efficiency of the pink shrimp Farfantepenaeus duorarum (Burkenroad, 1939) in habitats with different physical complexity in a tropical estuarine system.

    PubMed

    Corona; Soto; Sánchez

    2000-10-05

    Amphipod abundance and biomass were determined in soft-bottom substrates (SBS), monospecific Thalassia testudinum patches and T. testudinum with attached macroalgae (SAV) from Términos Lagoon. Amphipods were absent in SBS, and their density and biomass were higher in SAV (3351 individualsm(-2), 1718 mg AFDWm(-2)) than in T. testudinum (1220 indm(-2), 625 mg AFDWm(-2)). Although macroalgae and seagrasses are recognised as an alternative refuge against predation for amphipods, the high abundance of amphipods in SAV suggests that macroalgae represent a habitat that provides greater food availability. Pink shrimp Farfantepenaeus duorarum (Burkenroad, 1939) consumption rate (Mo) of epibenthic amphipods was experimentally evaluated. Mo intensifies as prey density increases and varied from 0.39 to 2.39 mg AFDWh(-1). Predation efficiency of F. duorarum on epibenthic amphipods was also evaluated in four artificial habitats with different physical complexity: soft-bottom substrates (SBS), small woody debris (SWD), seagrasses with densities of 300 and 1200 shootsm(-2) (S300 and S1200, respectively), macroalgae (MA), and at two prey densities (962 and 2406 indm(-2)). Amphipod consumption rate by F. duorarum varied from 1.20 to 2.07 indh(-1) in S1200 and MA, respectively. Habitat complexity had a significant effect on consumption rate, but prey density did not. Habitat physical complexity and predation efficiency maintained an inverse and a non-linear relationship. Presumably, the decrease in predation efficiency in association with the habitat complexity is due to the differential refuge value of these habitats. However, predation efficiency may also be influenced by either the microhabitat use by amphipods, the shrimp's dependence on seagrasses, or by differences in habitat value caused by the diel behavioural distribution pattern of amphipods and shrimp. Both field and experimental results highlight the importance of evaluating the relative value of tropical estuarine

  2. The Lithosphere-Asthenosphere System in the Calabrian Arc and Surrounding Seas Southern Italy

    NASA Astrophysics Data System (ADS)

    Pontevivo, Antonella; Panza, Giuliano Francesco

    2006-08-01

    A fairly detailed structural model of the lithosphere-asthenosphere system (thickness, S- and P-wave velocities of the crust and of the uppermost mantle layers) has been defined in the Calabrian Arc region (Southern Tyrrhenian Sea, Calabria and the northwestern part of the Ionian Sea) in Southern Italy using seismic data from literature as a priori constraints of the nonlinear inversion of surface-wave data. The main features identified by this study are: (1) A very shallow (less then 10 km deep) crust-mantle transition in the Southern Tyrrhenian Sea and a very low vs just below a very thin lid, in correspondence of the submarine volcanic bodies Magnaghi, Marsili and Vavilov, while the vs in the lid is quite high in the area that separates Marsili from Magnaghi-Vavilov; (2) a shallow and very low vs layer in the uppermost mantle in the areas of the Aeolian Islands, Vesuvius, Phlegraean Fields and Ischia, which represents their shallow-mantle magma source; (3) a thickened continental crust and lithospheric doubling in Calabria; (4) a crust about 25-km thick and a mantle velocity profile versus depth consistent with the presence of a continental rifted lithosphere, now thermally relaxed, in the investigated part of the Ionian Sea; (5) the subduction towards northwest of the Ionian lithosphere below the Southern Tyrrhenian Sea; (6) the subduction of the Adriatic/Ionian lithosphere underneath the Vesuvius and Phlegraean Fields.

  3. Mercury in estuarine sediments of the Manguaba and Botafogo River : A background and baseline values proposition in comparison to relatively well preserved and polluted aquatic systems under tropical countries

    NASA Astrophysics Data System (ADS)

    Lima, Marta

    2013-04-01

    Mercury in estuarine sediments of the Manguaba and Botafogo River : A background and baseline values proposition in comparison to relatively well preserved and polluted aquatic systems under tropical countries Lima, Marta1; Menor, Eldemar2; Lima, Enjolras3; Neumann, Virginio4 1MFGTransportes, Brazil; 2Federal University of Pernambuco, Brazil 3Servico Geologico do Brasil-CPRM, Brazil 4Federal University of Pernambuco, Brazil Heavy metal (HM) concentrations in estuarine sediments of the Botafogo and Manguaba river, North-eastern Brazil were investigated on basis of samples from a bottom core drill performed 4km from the mouth of the rivers. Total sediments (TS) of the sliced profiles (62 cm, Botafogo river and 87 cm, Manguaba river ) were submitted to chemical analysis (51 elements), mineralogical analysis (XRD) and statistical study, followed by stoichiometric calculations. Geochronologic determinations of 210Pb allowed studying the evolution of the contamination level approximately 150 year-old interval in the Botafogo river. Mercury (Hg) and Arsenic (As) are emphasized because of a chlorine-soda industry that dumps its effluents about 15 km upstream of the estuary and extensive cultivation of sugarcane existent in this watershed. Hg background in pelitic total sediments (PTS) was certain established considering the Hg content (126 ppb) in sedimentary intervals previous to 1910. The production of chlorine-soda (since 1963) coincides with a drastic increase of the Hg concentrations and contemporary values around 6.000 ppb, without interruption in the pollutant process. The conclusions found that the Hg was the main indicator of anthropogenic contribution in the sediments of the Botafogo river. On the other hand, an increase in the Hg-As concentrations has been observed at the last decades due to an increase of the clay mineral fraction in TS of the Manguaga river. This scenario indicates that the accumulation of HM has been constant since the last decades, under a

  4. LANDSCAPE STRUCTURE AND ESTUARINE CONDITION IN THE MID-ATLANTIC REGION OF THE UNITED STATES: I. DEVELOPING QUANTITATIVE RELATIONSHIPS

    EPA Science Inventory

    In a previously published study, quantitative relationships were developed between landscape metrics and sediment contamination for 25 small estuarine systems within Chesapeake Bay. Nonparametric statistical analysis (rank transformation) was used to develop an empirical relation...

  5. A framework for a diabetes mellitus disease management system in southern Israel.

    PubMed

    Fox, Matthew A; Harman-Boehm, Ilana; Weitzman, Shimon; Zelingher, Julian

    2002-01-01

    Chronic diseases are a significant burden on western healthcare systems and national economies. It has been suggested that automated disease management for chronic disease, like diabetes mellitus (DM), improves the quality of care and reduces inappropriate utilization of diagnostic and therapeutic measures. We have designed a comprehensive DM Disease Management system for the Negev region in southern Israel. This system takes advantage of currently used clinical and administrative information systems. Algorithms for DM disease management have been created based on existing and accepted Israeli guidelines. All data fields and tables in the source information systems have been analyzed, and interfaces for periodic data loads from these systems have been specified. Based on this data, four subsets of decision support algorithms have been developed. The system generates alerts in these domains to multiple end users. We plan to use the products of this information system analysis and disease management specification in the actual development process of such a system shortly.

  6. Polymorphism of the plasminogen (PLG) system in Cádiz Province, southern Spain.

    PubMed

    Gamero, J J; Romero, J L; Vizcaya, M A; Arufe, M I

    1991-01-01

    In this work, the authors report a plasminogen (PLG) system genetic-population study in a sample of 378 healthy subjects, of both sexes and unrelated, all resident in the province of Cádiz in Southern Spain. In this study, the PLG types were determined by isoelectric focusing in polyacrylamide gels (PAGIF), followed by staining with Coomassie blue. The genic frequencies obtained were the following: PLG A = 0.833 333 3; PLG B = 0.166 666 7.

  7. Visual tree grading systems for estimating lumber yields in young and mature southern pine

    Treesearch

    Alexander Clark; Robert H. McAlister

    1998-01-01

    New visual tree grading systems for mature southern pine ? 35 years old and young pine ? 35 years old based on number and size of branches in the lower bole are described. A series of lumber grade yield studies was conducted to test the new grading rules. A total of 214 natural loblolly pine (Pinus taeda L.) and shortleaf pine (P. echinata Mill) trees 9 to 20 inches...

  8. Transboundary movement of marine litter in an estuarine gradient: Evaluating sources and sinks using hydrodynamic modelling and ground truthing estimates.

    PubMed

    Krelling, Allan Paul; Souza, Mihael Machado; Williams, Allan Thomas; Turra, Alexander

    2017-06-15

    Marine debris' transboundary nature and new strategies to identify sources and sinks in coastal areas were investigated along the Paranaguá estuarine gradient (southern Brazil), through integration of hydrodynamic modelling, ground truthing estimates and regressive vector analysis. The simulated release of virtual particles in different parts of the inner estuary suggests a residence time shorter than 5days before being exported through the estuary mouth (intermediate compartment) to the open ocean. Stranded litter supported this pathway, with beaches in the internal compartment presenting proportionally more items from domestic sources, while fragmented items with unknown sources were proportionally more abundant in the oceanic beaches. Regressive vector analysis reinforced the inner estuarine origin of the stranded litter in both estuarine and oceanic beaches. These results support the applicability of simple hydrodynamic models to address marine debris' transboundary issues in the land-sea transition zone, thus supporting an ecosystem transboundary (and not territorial) management approach. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Global positioning system reoccupation of early triangulation sites - Tectonic deformation of the Southern Coast Ranges

    NASA Technical Reports Server (NTRS)

    Shen, Zheng-Kang; Jackson, David D.

    1993-01-01

    We study tectonic deformation in the Southern Coast Range, California. We use triangulation and astronomic azimuth data collected since 1875, trilateration since 1970, and global positioning system data collected from 1986 to 1987. Two modeling techniques have been used. An elastic block-fault model is applied to study the tectonic motion of the San Andreas Fault and the San Gregorio-Hosgri Fault. Station velocities are modeled to study regional deformations. Results show that the regional deformation is predominantly controlled by deep strike-slip motion along the San Andreas Fault, at a rate of 33 +/- 2 mm/yr. Deep slip along the San Gregorio-Hosgri Fault is about 0-4 mm/yr, assuming a locked suit to a depth of 20 km. Convergence normal to the San Andreas Fault in the Southern Coast Ranges is not greater than 0.02 microrad/yr.

  10. Global positioning system reoccupation of early triangulation sites - Tectonic deformation of the Southern Coast Ranges

    NASA Technical Reports Server (NTRS)

    Shen, Zheng-Kang; Jackson, David D.

    1993-01-01

    We study tectonic deformation in the Southern Coast Range, California. We use triangulation and astronomic azimuth data collected since 1875, trilateration since 1970, and global positioning system data collected from 1986 to 1987. Two modeling techniques have been used. An elastic block-fault model is applied to study the tectonic motion of the San Andreas Fault and the San Gregorio-Hosgri Fault. Station velocities are modeled to study regional deformations. Results show that the regional deformation is predominantly controlled by deep strike-slip motion along the San Andreas Fault, at a rate of 33 +/- 2 mm/yr. Deep slip along the San Gregorio-Hosgri Fault is about 0-4 mm/yr, assuming a locked suit to a depth of 20 km. Convergence normal to the San Andreas Fault in the Southern Coast Ranges is not greater than 0.02 microrad/yr.

  11. 15 CFR 921.51 - Estuarine research guidelines.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... conducted in a manner consistent with Estuarine Research Guidelines developed by NOAA. (b) A summary of the... funds discussed in § 921.50(c). (c) The Estuarine Research Guidelines are reviewed annually by...

  12. 15 CFR 921.51 - Estuarine research guidelines.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... conducted in a manner consistent with Estuarine Research Guidelines developed by NOAA. (b) A summary of the... funds discussed in § 921.50(c). (c) The Estuarine Research Guidelines are reviewed annually by...

  13. 15 CFR 921.51 - Estuarine research guidelines.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... conducted in a manner consistent with Estuarine Research Guidelines developed by NOAA. (b) A summary of the... funds discussed in § 921.50(c). (c) The Estuarine Research Guidelines are reviewed annually by...

  14. Hydrogeology, ground-water movement, and subsurface storage in the Floridan aquifer system in southern Florida

    USGS Publications Warehouse

    Meyer, Frederick W.

    1989-01-01

    The Floridan aquifer system of southern Florida is composed chiefly of carbonate rocks that range in age from early Miocene to Paleocene. The top of the aquifer system in southern Florida generally is at depths ranging from 500 to 1,000 feet, and the average thickness is about 3,000 feet. It is divided into three general hydrogeologic units: (1) the Upper Floridan aquifer, (2) the middle confining unit, and (3) the Lower Floridan aquifer. The Upper Floridan aquifer contains brackish ground water, and the Lower Floridan aquifer contains salty ground water that compares chemically to modern seawater. Zones of high permeability are present in the Upper and Lower Floridan aquifers. A thick, cavernous dolostone in the Lower Floridan aquifer, called the Boulder Zone, is one of the most permeable carbonate units in the world (transmissivity of about 2.5 x 107 feet squared per day). Ground-water movement in the Upper Floridan aquifer is generally southward from the area of highest head in central Florida, eastward to the Straits of Florida, and westward to the Gulf of Mexico. Distributions of natural isotopes of carbon and uranium generally confirm hydraulic gradients in the Lower Floridan aquifer. Groundwater movement in the Lower Floridan aquifer is inland from the Straits of Florida. The concentration gradients of the carbon and uranium isotopes indicate that the source of cold saltwater in the Lower Floridan aquifer is seawater that has entered through the karat features on the submarine Miami Terrace near Fort Lauderdale. The relative ages of the saltwater suggest that the rate of inland movement is related in part to rising sea level during the Holocene transgression. Isotope, temperature, and salinity anomalies in waters from the Upper Floridan aquifer of southern Florida suggest upwelling of saltwater from the Lower Floridan aquifer. The results of the study support the hypothesis of circulating relatively modern seawater and cast doubt on the theory that the

  15. Measuring the acute toxicity of estuarine sediments

    SciTech Connect

    DeWitt, T.H.; Swartz, R.C.; Lanberson, J.O.

    1989-01-01

    Estuarine sediments frequently are repositories and sources of anthropogenic contaminants. Toxicity is one method of assessing the environmental quality of sediments, yet because of the extreme range of salinities that characterize estuaries few infaunal organisms have both the physiological tolerance and sensitivity to chemical contaminants to serve in estuarine sediment toxicity tests. The study describes research on the estuarine burrowing amphipod, Eohaustorius estuarius Bosworth, 1973, whose survival was >95% in control sediments across a 2 to 28% salinity range over 10-d periods. E. estuarius also was acutely sensitive to low sediment concentrations of the polycyclic aromatic hydrocarbon, fluoranthene (LC50 approximately = 10.6 mg/kg), and its sensitivity to fluoranthene was not affected by salinity. E. estuarius was almost as sensitive as Rhepoxynius abronius to fluoranthene and to field-collected sediments from Puget Sound urban and industrial bays. E. estuarius was also more tolerant of very fine, uncontaminated sediments than R. abronius. Furthermore, E. estuarius was more sensitive to sediments spiked with fluoranthene than the freshwater amphipod, Hyalella azteca. E. estuarius, and possibly other estuarine haustoriid species, appears to be an excellent candidate for testing the acute toxicity if estuarine and marine sediments.

  16. A periodic freshwater patch detachment process from the Block Island Sound estuarine plume

    NASA Astrophysics Data System (ADS)

    Liu, Qianqian; Rothstein, Lewis M.; Luo, Yiyong

    2017-01-01

    Previous observations suggest periodic freshwater patches separating from the Block Island Sound (BIS) estuarine plume. In this study, the dynamics of the separation process is investigated through a series of numerical experiments using the Regional Ocean Modeling System (ROMS). In addition, we explore the seasonal variability of the freshwater patches and their response to river discharge and ambient current. The model results indicate that episodic freshwater patches are triggered by small changes in tidal currents over the spring-neap tidal cycle. The spring-neap variation in tidal currents causes significant, monthly fluctuations in turbulent mixing and vertical stratification in BIS, modulating the freshwater discharge thereby generating episodic freshwater patches that move both downstream along the southern shore of Long Island and toward Rhode Island Sound (RIS). The realistically configured model shows that the freshwater patches experience strong seasonal variability. They are largest in spring when the river discharge peaks, and smallest in summer due to the weak river discharge and a robust upstream ambient current from RIS. According to the analysis of the freshwater transport out of BIS, we conclude that such detachment occurs at tidal mixing fronts.

  17. Global climate impacts of fixing the Southern Ocean shortwave radiation bias in the Community Earth System Model (CESM)

    NASA Astrophysics Data System (ADS)

    Kay, J. E.; Medeiros, B.; Yettella, V. K. R.; Hannay, C.; Caldwell, P.; Wall, C.; Bitz, C. M.

    2015-12-01

    A large, long-standing, and pervasive climate model bias is excessive absorbed shortwave radiation (ASR) over the mid-latitude oceans, especially the Southern Ocean. We investigate both the underlying mechanisms for and climate impacts of this bias within the Community Earth System Model with the Community Atmosphere Model version 5 (CESM-CAM5). Excessive Southern Ocean ASR in CESM-CAM5 results in part because low-level clouds contain insufficient amounts of supercooled liquid. In a present-day atmosphere-only run, an observationally motivated modification to the shallow convection detrainment increases supercooled cloud liquid, brightens low-level clouds, and substantially reduces the Southern Ocean ASR bias. Tuning to maintain global energy balance enables reduction of a compensating tropical ASR bias. In the resulting pre-industrial fully coupled run with a brighter Southern Ocean and dimmer Tropics, the Southern Ocean cools and the Tropics warm. As a result of the enhanced meridional temperature gradient, poleward heat transport increases in both hemispheres (especially the Southern Hemisphere) and the Southern Hemisphere atmospheric jet strengthens. Cross-equatorial heat transport increases in the ocean, but not in the atmosphere. As a result, a proposed atmospheric teleconnection that links Southern Ocean ASR bias reduction and cooling with northward shifts in the Intertropical Convergence Zone is not found. All results discussed above are for the transient response. Ongoing work to assess the equilibrium response and the impact of the fix climate change experiments results will also be presented.

  18. TOP DOWN CONTROL OF THE MICROBIAL LOOP IN ESTUARINE PHYTOPLANKTON

    EPA Science Inventory

    Top Down Control of the Microbial Loop in Estuarine Plankton (Abstract). To be presented at the 16th Biennial Conference of the Estuarine Research Foundation, ERF 2001: An Estuarine Odyssey, 4-8 November 2001, St. Pete Beach, FL. 1 p. (ERL,GB R846).

    We examined the effects...

  19. TOP DOWN CONTROL OF THE MICROBIAL LOOP IN ESTUARINE PHYTOPLANKTON

    EPA Science Inventory

    Top Down Control of the Microbial Loop in Estuarine Plankton (Abstract). To be presented at the 16th Biennial Conference of the Estuarine Research Foundation, ERF 2001: An Estuarine Odyssey, 4-8 November 2001, St. Pete Beach, FL. 1 p. (ERL,GB R846).

    We examined the effects...

  20. Semiannual variability of the California Undercurrent along the Southern California Current System: A tropical generated phenomenon

    NASA Astrophysics Data System (ADS)

    Gómez-Valdivia, Felipe; Parés-Sierra, Alejandro; Laura Flores-Morales, Ana

    2017-02-01

    We used a high-resolution numerical model implementation to analyze the California Undercurrent (CU) dynamics along the Southern California Current System. In agreement with reported observations, the modeled CU was stronger during June-July and December-January, when it flowed continuously along Baja California and Southern California reaching long-term averages up to 6 cm s-1. Previous research has associated the biannual CU intensification to the local dynamics off Southern California. Our results evidenced, however, that the passage of remote Semiannual Coastal-Trapped Waves (SCTW) primarily explained the semiannual CU variability. The CU was stronger 2-3 months after the passage of the upwelling SCTW phase, when the offshore propagation of Rossby waves, brought about by the SCTW transit, induced an energetic cross-shore pressure gradient that strengthened the subsurface poleward circulation along the continental slope. The SCTW were independent of the local wind; they corresponded to the northward extension of semiannual equatorial Kelvin waves that have been observed along the northeastern tropical Pacific.

  1. The Southern Hills regional aquifer system of southeastern Louisiana and southwestern Mississippi

    USGS Publications Warehouse

    Buono, A.

    1983-01-01

    The Southern Hills regional aquifer system, named in a petition to the Environmental Protection Agency for designation as a sole or principal source of drinking water, is the primary source of public and domestic supplies in the northern 10 parishes of southeastern Louisiana. The gulfward dipping and thickening, complexly interbedded aquifer system extends from the northern limit of the recharge area near Vicksburg, Mississippi, as far as the Baton Rouge area in southeastern Louisiana. As many as 13 interdependent aquifer units compose the system in the southern part of the area and are known to coalesce or pinch out northward (updip) into fewer units. Aquifer water is almost exclusively a soft, sodium bicarbonate type with an average dissolved-solids concentration of about 220 milligrams per liter in southeastern Louisiana. Although several streams are available as alternatives for supply, they have not been accepted by local officials because of the additional water treatment that would be necessary and the extensive distribution system needed to deliver water to areas not near a source stream. Groundwater use in 1980 for public and domestic supply averaged 121 Mgal/d (million gallons per day), serving 744,000 people in southeastern Louisiana. In southwestern Mississippi, where the aquifer system is also the primary source for public and domestic supply, water use for these categories in 1980 totaled 25 Mgal/d, serving about 273,000 people. (USGS)

  2. IDESSA: An Integrative Decision Support System for Sustainable Rangeland Management in Southern African Savannas

    NASA Astrophysics Data System (ADS)

    Meyer, Hanna; Authmann, Christian; Dreber, Niels; Hess, Bastian; Kellner, Klaus; Morgenthal, Theunis; Nauss, Thomas; Seeger, Bernhard; Tsvuura, Zivanai; Wiegand, Kerstin

    2017-04-01

    Bush encroachment is a syndrome of land degradation that occurs in many savannas including those of southern Africa. The increase in density, cover or biomass of woody vegetation often has negative effects on a range of ecosystem functions and services, which are hardly reversible. However, despite its importance, neither the causes of bush encroachment, nor the consequences of different resource management strategies to combat or mitigate related shifts in savanna states are fully understood. The project "IDESSA" (An Integrative Decision Support System for Sustainable Rangeland Management in Southern African Savannas) aims to improve the understanding of the complex interplays between land use, climate patterns and vegetation dynamics and to implement an integrative monitoring and decision-support system for the sustainable management of different savanna types. For this purpose, IDESSA follows an innovative approach that integrates local knowledge, botanical surveys, remote-sensing and machine-learning based time-series of atmospheric and land-cover dynamics, spatially explicit simulation modeling and analytical database management. The integration of the heterogeneous data will be implemented in a user oriented database infrastructure and scientific workflow system. Accessible via web-based interfaces, this database and analysis system will allow scientists to manage and analyze monitoring data and scenario computations, as well as allow stakeholders (e. g. land users, policy makers) to retrieve current ecosystem information and seasonal outlooks. We present the concept of the project and show preliminary results of the realization steps towards the integrative savanna management and decision-support system.

  3. Habitat residency and movement patterns of Centropomus parallelus juveniles in a subtropical estuarine complex.

    PubMed

    Daros, F A; Spach, H L; Correia, A T

    2016-05-01

    Sixty Centropomus parallelus juveniles were collected in March 2013 in two locations (Tromomó and Guaraguaçu) inside the Paranaguá estuarine complex, southern Brazil. The habitat residency and movement patterns of the individuals were inferred from Sr:Ca ratios and age recorded in the otoliths. Data suggest that the species spawns preferentially in brackish areas mainly from October to January, and that growth rate during the early juvenile stage could be influenced by environmental salinity. Furthermore, the data also show that C. parallelus can occupy diverse salinity habitats and migrate among marine, brackish and freshwater areas within the Paranaguá estuarine complex, showing a high environmental plasticity and adaptation.

  4. The Role Of Coastal Management In Regulating Estuarine Fluxes

    NASA Astrophysics Data System (ADS)

    Jickells, T. D.

    2014-12-01

    Human activity is known to be increasing the fluxes of many nutrients and trace elements in many river systems. However, the impact of riverine inputs depends not only on the riverine nutrient flux, but also on its retention in estuaries and near shore coastal systems. The retention of nutrients and trace elements in coastal systems depends at least in part on particle water interactions. These interactions in turn depend on the physical configuration of the system which regulates processes such as resuspension and water-sediment interactions. Human activity is massively altering the shape of many estuaries by activities such as reclamation and flood defence. These changes have obvious and well documented ecological impacts. I will show using examples from UK systems how these changes in estuarine "geography" also greatly alter the effectiveness of estuaries as filters for nutrients and trace elements, with the potential to have a major impact on the fluxes of fluvial material to the continental shelf on regional scales. Rising sea levels are beginning to enforce a change of management strategy in coastal systems and this in turn may have major impacts on estuarine nutrient retention.

  5. Remote sensing and landscape analysis of indicators of estuarine condition in the northeastern United States

    NASA Astrophysics Data System (ADS)

    Rodriguez, Wilfrid

    I focused on four questions: (1) are measures of estuarine water quality the same across study regions; (2) are spatial setting variables and intense rainfall events important in explaining variation in water quality measures; (3) what is the relationship between patterns of land cover and estuarine condition; and (4) is land-cover change a good regional indicator of estuarine condition? Estuarine data was extracted from the Environmental Monitoring and Assessment Program (EMAP) and Coastal-2000 surveys. Geographical Information System's modeling, land cover change detection, cumulative distribution functions and multiple linear regression analyses were used to quantify land-water interactions in three regions representing urban and agricultural gradients along the Virginian Biogeographic Province in the eastern coast of the United States. Spatial setting variables (riverine, lagoonal, oceanic) plus rainfall accounted for the effect of location on measurements of estuarine condition. After removing spatial setting effect from estuarine condition data, weak but significant relationships were found between total urban area (within a 4-km buffer from measuring stations) and water quality indicators for the three regions. The effect of spatial setting on indicators of estuarine condition was strikingly high in Delmarva, where distance-to-shore, and oceanic and riverine categories significantly explained variability of sediment organics (Fluorant: R2 = 0.79; P < 0.001; Dieldrin: R2 = 0.91; P < 0.001; PCBs: R2 = 0.96; P < 0.001). Lagoonal locations also had a significant negative effect on arsenic, cadmium, and lead, and explained between 32 to 53% of their variation. Land-cover change on estuarine condition on each region showed clear differences in patterns between Delmarva and the other two areas during the 1984--92 period. In Delmarva, land cover change in buffer zones 6-, 8-, and 10-km from monitoring stations had a significant effect on the Benthic Index, silver

  6. Inconsistencies in coastal dune genesis and development in the western Mediterranean Cabopino Dune system, southern Spain

    NASA Astrophysics Data System (ADS)

    Guisado-Pintado, Emilia; Malvárez, Gonzalo; Jackson, Derek; Navas, Fatima

    2016-04-01

    It is generally agreed that a falling sea level regime is required in the long term to establish dunes as distinctive landform features along a coast. Sedimentary (supply) bodies from fluvial, glacial sources or marine platform processes also need to be in place. In most Atlantic-facing coastal dune systems the current morpho-sedimentary structures are usually associated with the period between 18K BP and present when both glacial and riverine sediments emplaced sediments within the active zone of present sea level to help form beaches and dunes. Mediterranean coastal dunes fronted by steep continental shelves, such as in the western Mediterranean coast of southern Spain are, however, not associated with glacial deposits and thus are only present in association with river mouths and/or coastal lagoons. Their development is attributed to very recent sediment supply, which, combined with other forcing factors such as wind and waves, several orders of magnitude below those of north Atlantic systems, explains their limited extent. Some coastal dune fields however, do not seem to respond to this general pattern because of their scale and, more importantly, their origin linked possibly to marine platform processes rather than riverine or lagoonal development. Here, we examine the Cabopino dune system in southern Spain offering a conceptual model of their genesis and development as an "Atlantic" dune system within a Mediterranean setting. This is demonstrated by their scale (the largest in the Spanish Mediterranean) and their morphodynamic link to nearshore and platform processes in the last 18,000 years.

  7. The Cenozoic Denali Fault System and the Cretaceous accretionary development of southern Alaska

    NASA Astrophysics Data System (ADS)

    Csejtey, Béla, Jr.; Cox, Dennis P.; Evarts, Russell C.; Stricker, Gary D.; Foster, Helen L.

    1982-05-01

    The juxtaposition of disparate geologic terranes in southern Alaska has been previously interpreted to be mainly the result of several hundred kilometers of right lateral offset along the Denali fault system in Cenozoic time. Recent geologic investigations in the Healy quadrangle strongly suggest that Cenozoic horizontal displacements of such magnitude along the Denali fault system do not exist. In the Healy quadrangle, isograds and metamorphic facies boundaries of an early Late Cretaceous metamorphic belt trend across the Cenozoic McKinley strand of the Denali system without significant horizontal offsets. The present geologic makeup of most of southern Alaska is primarily the result of the Talkeetna superterrane, consisting of the previously assembled Peninsular terrane and Wrangellia, colliding with and subsequently being thrust upon the Yukon-Tanana and Nixon Fork terranes of the ancient North American continent in about middle Cretaceous time. The leading edge of the Talkeetna superterrane faces a wide, complexly deformed zone that contains numerous northwestward thrust miniterranes tectonically intermixed with Jurassic and Cretaceous flysch. The flysch is interpreted to have been deposited mostly in the narrowing and subsequently collapsed oceanic basin between the converging continental blocks. The postcollisional Denali fault system developed in Cenozoic time across the already accreted continental margin, in eastern Alaska along an older, Cretaceous suture.

  8. Toxicity of ozonated estuarine water to juvenile blue crabs (Callinectes sapidus) and Juvenile Atlantic menhaden (Brevoortia tyrannus)

    SciTech Connect

    Richardson, L.B.; Burton, D.T.

    1981-02-01

    Large quantitites of estuarine and marine water are treated with chlorine to prevent condenser system fouling at power plants. Chlorine and its residual by-products, however, are toxic to many forms of aquatic life. Ozone is one alternative oxidant which has proven to be an effective biocide and disinfectant in many fresh water applications. Ozonation of estuarine and marine waters, however, may produce residual compounds similar to those produced by chlorination. This study was initiated to provide baseline information on the toxicity of ozonated estuarine water to two representative estuarine species. The blue crab, Callinectes sapidus Rathbun, and the Atlantic menhaden, Brevoortia tyrannus Latrobe, were selected because of their wide distribution and commercial importance. The toxicity of ozone has been compared with chlorine toxicity data from the literature in an effort to examine possible similarities in toxicity.

  9. Constraints on the mechanics of the Southern San Andreas fault system from GPS velocity and stress

    NASA Astrophysics Data System (ADS)

    Becker, T. W.; Hardebeck, J. L.; Anderson, G.

    2003-12-01

    We use Global Positioning System (GPS) derived velocities and stress-orientations to study the distribution of long-term slip on the system of faults comprising the southern California plate boundary region. Of particular interest is how slip is partitioned over multiple earthquake cycles between the San Andreas Fault (SAF), the San Jacinto Fault (SJF) and the Eastern California Shear Zone. Some prior paleoseismologic and geodetic work places the majority of slip on the SAF. Other studies, however, find that the SJF accommodates about half of the slip in the south, implying half as much slip on the San Bernardino segment of the SAF. Two new data sets are used to further constrain the mechanics of the SAF. The first is the Southern California Earthquake Center's geodetic velocity field version 3 (Shen et al., 2003), which includes much improved coverage over prior models. The second is a regional map of stress field orientations at seismogenic depths, as determined from an inversion of earthquake focal mechanisms. While GPS data has been used in similar studies, this is the first application of stress field observations to this problem. We construct a simplified version of the southern California fault system, and model the surface velocities using a block model with elastic strain accumulation, following Meade et al. (2002). Additionally, we model the stress orientations at seismogenic depths, assuming that the stress field results from the loading of active faults. An inversion for fault slip rates is performed to simultaneously fit the GPS and stress observations. The model fit to the data is good in general, indicating that a simple mechanical model can capture both observed interseismic strain and stress accumulation. We evaluate the sensitivity of the slip rate solutions to the different datasets and identify "anomalous" fault segments with stresses that deviate from our simple loading model.

  10. Estuarine density fronts and their effect on oil slicks

    NASA Technical Reports Server (NTRS)

    Klemas, V. (Principal Investigator); Polis, D. F.; Davis, G. R.

    1976-01-01

    The author has identified the following significant results. Estuarine fronts represent regions of extremely high gradient or discontinuity in various parameters of physical interest, the most important being the water velocity and density fields. Aircraft and boats were combined to study the behavior of different types of fronts in Delaware Bay and their effect on pollutants in order to provide a basis for improving an oil drift and spreading model. Imagery from the LANDSAT satellites provided the most effective means of determining the location and extent of frontal systems over all portions of the tidal cycle. This data is being used to modify the oil drift and spreading model.

  11. The diamondback terrapin: The biology, ecology, cultural history, and conservation status of an obligate estuarine turtle

    USGS Publications Warehouse

    Hart, K.M.; Lee, D.S.; ,

    2006-01-01

    Ranging from Cape Cod to nearly the Texas-Mexico border, the diamondback terrapin (Malaclemys terrapin) is the only species of North American turtle restricted to estuarine systems. Despite this extensive distribution, its zone of occurrence is very linear, and in places fragmented, resulting in a relatively small total area of occupancy. On a global scale, excluding marine species, few turtles even venture into brackish water on a regular basis, and only two Asian species approach the North American terrapin's dependency on estuarine habitats. Here we describe some of the biological and behavioral adaptations of terrapins that allow them to live in the rather harsh estuarine environment. In this chapter we review the natural and cultural history of this turtle, discuss conservation issues, and provide information on the types of research needed to make sound management decisions for terrapin populations in peril.

  12. An 'extreme' future for estuaries? Effects of extreme climatic events on estuarine water quality and ecology.

    PubMed

    Wetz, Michael S; Yoskowitz, David W

    2013-04-15

    Recent climate observations suggest that extreme climatic events (ECE; droughts, floods, tropical cyclones, heat waves) have increased in frequency and/or intensity in certain world regions, consistent with climate model projections that account for man's influence on the global climate system. A synthesis of existing literature is presented and shows that ECE affect estuarine water quality by altering: (1) the delivery and processing of nutrients and organic matter, (2) physical-chemical properties of estuaries, and (3) ecosystem structure and function. From the standpoint of estuarine scientists and resource managers, a major scientific challenge will be to project the estuarine response to ECE that will co-occur with other important environmental changes (i.e., natural climate variability, global warming, sea level rise, eutrophication), as this will affect the provisioning of important ecosystem services provided by estuaries.

  13. The 2014-2015 warming anomaly in the Southern California Current System observed by underwater gliders

    NASA Astrophysics Data System (ADS)

    Zaba, Katherine D.; Rudnick, Daniel L.

    2016-02-01

    Large-scale patterns of positive temperature anomalies persisted throughout the surface waters of the North Pacific Ocean during 2014-2015. In the Southern California Current System, measurements by our sustained network of underwater gliders reveal the coastal effects of the recent warming. Regional upper ocean temperature anomalies were greatest since the initiation of the glider network in 2006. Additional observed physical anomalies included a depressed thermocline, high stratification, and freshening; induced biological consequences included changes in the vertical distribution of chlorophyll fluorescence. Contemporaneous surface heat flux and wind strength perturbations suggest that local anomalous atmospheric forcing caused the unusual oceanic conditions.

  14. The Southern Argentina Agile MEteor Radar Orbital System (SAAMER-OS): An Initial Sporadic Meteoroid Orbital Survey in the Southern Sky

    NASA Astrophysics Data System (ADS)

    Janches, D.; Close, S.; Hormaechea, J. L.; Swarnalingam, N.; Murphy, A.; O'Connor, D.; Vandepeer, B.; Fuller, B.; Fritts, D. C.; Brunini, C.

    2015-08-01

    We present an initial survey in the southern sky of the sporadic meteoroid orbital environment obtained with the Southern Argentina Agile MEteor Radar (SAAMER) Orbital System (OS), in which over three-quarters of a million orbits of dust particles were determined from 2012 January through 2015 April. SAAMER-OS is located at the southernmost tip of Argentina and is currently the only operational radar with orbit determination capability providing continuous observations of the southern hemisphere. Distributions of the observed meteoroid speed, radiant, and heliocentric orbital parameters are presented, as well as those corrected by the observational biases associated with the SAAMER-OS operating parameters. The results are compared with those reported by three previous surveys performed with the Harvard Radio Meteor Project, the Advanced Meteor Orbit Radar, and the Canadian Meteor Orbit Radar, and they are in agreement with these previous studies. Weighted distributions for meteoroids above the thresholds for meteor trail electron line density, meteoroid mass, and meteoroid kinetic energy are also considered. Finally, the minimum line density and kinetic energy weighting factors are found to be very suitable for meteroid applications. The outcomes of this work show that, given SAAMER’s location, the system is ideal for providing crucial data to continuously study the South Toroidal and South Apex sporadic meteoroid apparent sources.

  15. THE SOUTHERN ARGENTINA AGILE METEOR RADAR ORBITAL SYSTEM (SAAMER-OS): AN INITIAL SPORADIC METEOROID ORBITAL SURVEY IN THE SOUTHERN SKY

    SciTech Connect

    Janches, D.; Swarnalingam, N.; Close, S.; Hormaechea, J. L.; Murphy, A.; O’Connor, D.; Vandepeer, B.; Fuller, B.; Fritts, D. C.; Brunini, C. E-mail: nimalan.swarnalingam@nasa.gov E-mail: jlhormaechea@untdf.edu.ar E-mail: doconnor@gsoft.com.au E-mail: bfuller@gsoft.com.au E-mail: claudiobrunini@yahoo.com

    2015-08-10

    We present an initial survey in the southern sky of the sporadic meteoroid orbital environment obtained with the Southern Argentina Agile MEteor Radar (SAAMER) Orbital System (OS), in which over three-quarters of a million orbits of dust particles were determined from 2012 January through 2015 April. SAAMER-OS is located at the southernmost tip of Argentina and is currently the only operational radar with orbit determination capability providing continuous observations of the southern hemisphere. Distributions of the observed meteoroid speed, radiant, and heliocentric orbital parameters are presented, as well as those corrected by the observational biases associated with the SAAMER-OS operating parameters. The results are compared with those reported by three previous surveys performed with the Harvard Radio Meteor Project, the Advanced Meteor Orbit Radar, and the Canadian Meteor Orbit Radar, and they are in agreement with these previous studies. Weighted distributions for meteoroids above the thresholds for meteor trail electron line density, meteoroid mass, and meteoroid kinetic energy are also considered. Finally, the minimum line density and kinetic energy weighting factors are found to be very suitable for meteroid applications. The outcomes of this work show that, given SAAMER’s location, the system is ideal for providing crucial data to continuously study the South Toroidal and South Apex sporadic meteoroid apparent sources.

  16. The Southern Argentina Agile Meteor Radar Orbital System (SAAMER-OS): An Initial Sporadic Meteoroid Orbital Survey in the Southern Sky

    NASA Technical Reports Server (NTRS)

    Janches, D.; Close, S.; Hormaechea, J. L.; Swarnalingam, N.; Murphy, A.; O'Connor, D.; Vandepeer, B.; Fuller, B.; Fritts, D. C.; Brunini, C.

    2015-01-01

    We present an initial survey in the southern sky of the sporadic meteoroid orbital environment obtained with the Southern Argentina Agile MEteor Radar (SAAMER) Orbital System (OS), in which over three-quarters of a million orbits of dust particles were determined from 2012 January through 2015 April. SAAMER-OS is located at the southernmost tip of Argentina and is currently the only operational radar with orbit determination capability providing continuous observations of the southern hemisphere. Distributions of the observed meteoroid speed, radiant, and heliocentric orbital parameters are presented, as well as those corrected by the observational biases associated with the SAAMER-OS operating parameters. The results are compared with those reported by three previous surveys performed with the Harvard Radio Meteor Project, the Advanced Meteor Orbit Radar, and the Canadian Meteor Orbit Radar, and they are in agreement with these previous studies. Weighted distributions for meteoroids above the thresholds for meteor trail electron line density, meteoroid mass, and meteoroid kinetic energy are also considered. Finally, the minimum line density and kinetic energy weighting factors are found to be very suitable for meteoroid applications. The outcomes of this work show that, given SAAMERs location, the system is ideal for providing crucial data to continuously study the South Toroidal and South Apex sporadic meteoroid apparent sources.

  17. The Southern Argentina Agile Meteor Radar Orbital System (SAAMER-OS): An Initial Sporadic Meteoroid Orbital Survey in the Southern Sky

    NASA Technical Reports Server (NTRS)

    Janches, D.; Close, S.; Hormaechea, J. L.; Swarnalingam, N.; Murphy, A.; O'Connor, D.; Vandepeer, B.; Fuller, B.; Fritts, D. C.; Brunini, C.

    2015-01-01

    We present an initial survey in the southern sky of the sporadic meteoroid orbital environment obtained with the Southern Argentina Agile MEteor Radar (SAAMER) Orbital System (OS), in which over three-quarters of a million orbits of dust particles were determined from 2012 January through 2015 April. SAAMER-OS is located at the southernmost tip of Argentina and is currently the only operational radar with orbit determination capability providing continuous observations of the southern hemisphere. Distributions of the observed meteoroid speed, radiant, and heliocentric orbital parameters are presented, as well as those corrected by the observational biases associated with the SAAMER-OS operating parameters. The results are compared with those reported by three previous surveys performed with the Harvard Radio Meteor Project, the Advanced Meteor Orbit Radar, and the Canadian Meteor Orbit Radar, and they are in agreement with these previous studies. Weighted distributions for meteoroids above the thresholds for meteor trail electron line density, meteoroid mass, and meteoroid kinetic energy are also considered. Finally, the minimum line density and kinetic energy weighting factors are found to be very suitable for meteoroid applications. The outcomes of this work show that, given SAAMERs location, the system is ideal for providing crucial data to continuously study the South Toroidal and South Apex sporadic meteoroid apparent sources.

  18. Climate influence on juvenile European sea bass (Dicentrarchus labrax, L.) populations in an estuarine nursery: A decadal overview.

    PubMed

    Bento, Eduardo G; Grilo, Tiago F; Nyitrai, Dániel; Dolbeth, Marina; Pardal, Miguel Ângelo; Martinho, Filipe

    2016-12-01

    Estuarine systems support the life cycle stages of commercially important marine fish and are influenced by large and local-scale climatic patterns. In this study, performed in the Mondego estuary, Portugal, we used an 11-year database (2003-2013) for analyzing the variability in the population of a marine juvenile migrant fish, the European sea bass Dicentrarchus labrax, regarding changes in abundance, population structure, growth rates, secondary production and annual day of peak abundance. Higher densities and production occurred in 2003, but no differences in 0-group growth could be observed. In order to detect change points in both biological and climatic data, the cumulative sum (CUSUM) of the deviations from the mean for the 2003-2013 period were determined for each parameter. The relationship between large and local-scale drivers and 0-group biological attributes were evaluated using a Spearman rank correlation analysis of CUSUM of biological and environmental data, considering the correspondent yearly values and with a time-lag of 1 year. The North Atlantic Oscillation (NAO) index, sea surface temperature (SST) and their respective winter values were tested as large-scale factors, while river runoff, salinity and estuarine water temperature were considered as local climate patterns. The significant factors explaining D. labrax 0-group abundance and production were salinity and the NAO, the latter being also a significant predictor considering the 1-year lag. The NAO with 1-year lag was also positively correlated with the day of peak abundance. The early stages of European sea bass were demonstrated to have a climate-dependent life cycle, controlled by variations in both large-scale climatic patterns and local features. In southern European marine populations, the effects of the NAO seem less direct, and dependent on the magnitude of its expressions and on the time scale considered.

  19. Assessing dissolved carbon transport and transformation along an estuarine river with stable isotope analyses

    NASA Astrophysics Data System (ADS)

    He, Songjie; Xu, Y. Jun

    2017-10-01

    Estuaries play an important role in the dynamics of dissolved carbon from rivers to coastal oceans. However, our knowledge of dissolved carbon transport and transformation in mixing zones of the world's coastal rivers is still limited. This study aims to determine how dissolved inorganic carbon (DIC) and dissolved organic carbon (DOC) concentrations and stable isotopes (δ13CDIC and δ13CDOC) change along an 88-km long estuarine river, the Calcasieu River in Louisiana, southern USA, with salinity ranging from 0.02 to 21.92. The study is expected to elucidate which processes most likely control carbon dynamics in a freshwater-saltwater mixing system, and to evaluate the net metabolism of this estuary. Between May 2015 and February 2016, water samples were collected and in-situ measurements on ambient water conditions were performed during five field trips at six sites from upstream to downstream of the Calcasieu River, which enters the Northern Gulf of Mexico (NGOM). The DIC concentration and δ13CDIC increased rapidly with increasing salinity in the mixing zone. The average DIC concentration and δ13CDIC at the site closest to the NGOM (site 6) were 1.31 mM and -6.34‰, respectively, much higher than those at the site furthest upstream (site 1, 0.42 mM and -20.83‰). The DIC concentrations appeared to be largely influenced by conservative mixing, while high water temperature may have played a role in deviating DIC concentration from the conservative line due likely to increased respiration and decomposition. The δ13CDIC values were close to those suggested by the conservative mixing model for May, June and November, but lower than those for July and February, suggesting that an estuarine river can fluctuate from a balanced to a heterotrophic system (i.e., production/respiration (P/R) < 1) seasonally. Unlike the DIC longitudinal trend, the DOC concentrations in the river estuary decreased from upstream to downstream, but to a much smaller degree. The DOC

  20. Turing Patterns in Estuarine Sediments by Microbiological Activity

    NASA Astrophysics Data System (ADS)

    De Morais Mendonca Teles, Antonio

    2016-07-01

    The use of Turing mechanisms and lattice Lotka-Volterra model (LLV), also by means of the non-extensive statistical mechanics, can mathematically describe well the phenomena of clustering and their associated boundaries with fractal dimensionality, which occurs in various natural situations, among them, biogeochemical processes via microorganisms in estuarine and marine sediments on the planet Earth. The author did an experimental analysis in field work which took into account the spatial and temporal behavior of Turing patterns, in the form of microbial activity within estuarine subsurface sediments. We show we can find the characteristics of clustering and fractallity which are present in the dynamical LLV model and Turing patterns mechanisms, and the non-extensive statistical mechanics could be used to find the q-entropy (Sq), and other non-equilibrium statistical parameters of the studied estuarine (Caraís lagoon) subsurface biogeochemical system. In this paper, the author suggests that such kinds of subsurface ecological systems are of interest to Astrobiology because if we find Turing-type clustered geomorphological patterns, below meter scale, on the near subsurface and inside rocks at the surface of planet Mars, and also find non-equilibrium statistical parameters (temperature, [F], [C], [S], etc.), displaying Turing-type mechanism, in the aquatic environments of the internal seas of planets Jupiter's moon Europa and the internal global ocean of Saturn's moon Enceladus, that could mean that possible hypothetical biogeochemical activities are present in such places. This could be a bio-indicator tool. And with further studies we could find the q-entropy Sq to establish better defined statistical mechanical parameters for such environments and to refine models for their evolution, as we do on planet Earth.

  1. Variations in Reading Achievement Across 14 Southern African School Systems: Which Factors Matter?

    NASA Astrophysics Data System (ADS)

    Hungi, Njora; Thuku, Florence W.

    2010-02-01

    In this study the authors employed a multilevel analysis procedure in order to examine the pupil and school levels factors that contributed to variation in reading achievement among Grade 6 primary school pupils in 14 southern African school systems (Botswana, Kenya, Lesotho, Malawi, Mauritius, Mozambique, Namibia, Seychelles, South Africa, Swaziland, Tanzania, Uganda, Zambia, and Zanzibar). The data for this study were collected in 2002 as part of a major project known as the Southern and Eastern Africa Consortium for Monitoring Educational Quality (SACMEQ) that sought to examine the quality of education offered in primary schools in these countries. The most important factors affecting variation in pupil achievement across most of these school systems were grade repetition, pupil socioeconomic background, speaking the language of instruction at home, and Pupil age. South Africa, Uganda and Namibia were among the school systems with the largest between-school variation while Seychelles and Mauritius had the largest within-school variation. Low social equity in reading achievement was evident in Mauritius, Seychelles and Tanzania. Policy implications of the findings are discussed.

  2. Remobilization of southern African desert dune systems by twenty-first century global warming.

    PubMed

    Thomas, David S G; Knight, Melanie; Wiggs, Giles F S

    2005-06-30

    Although desert dunes cover 5 per cent of the global land surface and 30 per cent of Africa, the potential impacts of twenty-first century global warming on desert dune systems are not well understood. The inactive Sahel and southern African dune systems, which developed in multiple arid phases since the last interglacial period, are used today by pastoral and agricultural systems that could be disrupted if climate change alters twenty-first century dune dynamics. Empirical data and model simulations have established that the interplay between dune surface erodibility (determined by vegetation cover and moisture availability) and atmospheric erosivity (determined by wind energy) is critical for dunefield dynamics. This relationship between erodibility and erosivity is susceptible to climate-change impacts. Here we use simulations with three global climate models and a range of emission scenarios to assess the potential future activity of three Kalahari dunefields. We determine monthly values of dune activity by modifying and improving an established dune mobility index so that it can account for global climate model data outputs. We find that, regardless of the emission scenario used, significantly enhanced dune activity is simulated in the southern dunefield by 2039, and in the eastern and northern dunefields by 2069. By 2099 all dunefields are highly dynamic, from northern South Africa to Angola and Zambia. Our results suggest that dunefields are likely to be reactivated (the sand will become significantly exposed and move) as a consequence of twenty-first century climate warming.

  3. Holocene history of the estuarine area surrounding Portage, Alaska, as recorded in a 93 m core.

    USGS Publications Warehouse

    Bartsch-Winkler, S.; Ovenshine, A.T.; Kachadoorian, R.

    1983-01-01

    Records four prograding cycles of estuarine deposition for the past 8230 + or - 100 years. Analyses of texture, mineralogy, paleontology, and sedimentary structures enable definition of eight lithologic units. Mineralogic studies show that past and present sedimentation at Portage has been largely mud and sand from the Susitna River on the NW side of Cook Inlet. Sedimentation rates for four intervals show rates to be higher and to vary more at depth than rates nearer the surface. Presently, deposition is accomplished 'instantly' as the result of tectonic subsidence and compaction of sediment caused by periodic earthquakes, in combination with a turbid estuarine system. -from Authors

  4. Evolution of Paleogene submarine Canyon-Fan systems, southern Sacramento basin, California

    SciTech Connect

    Fischer, P.J.; Cherven, V.B.; Almgren, A.A.

    1986-04-01

    The evolutionary development of the Paleogene Martinez and Meganos Submarine Canyon and Fan systems of the southern Sacramento basin was controlled by a complex interplay of eustatic sea level change and tectonism. In this brief synthesis, the authors postulated that eustatic sea level changes were the dominant or controlling factor, and tectonism, although significant, was of secondary importance. The development of the Paleogene canyon and fan systems is correlated with low sea level stands or regressions at 60 Ma and 56 Ma. Intermittent tectonism, beginning at least 5-10 m.y. earlier, particularly along the western and southwestern margins of the Sacramento basin, controlled the location of the canyon and fan systems. The controlling tectonic elements of the southern basin were north-trending, high-angle faults related to the Kirby Hills and Midland fault zones and the Diablo-Kirby Hills(.) uplift. Both canyons were probably active (that is, channeling coarse sediment to their fans) during most of the late Paleocene. The authors suggest that canyon activity was maintained by south-flowing longshore drift or feeder systems, down-canyon gravity flows (turbidites, etc) and up-down canyon current systems, all of which are typical of modern, active submarine canyon and fan systems. The canyons filled with fine-grained sediments when the canyons were beheaded or separated from the longshore drift system by rising sea level, or when tectonism(.) shifted the major river drainage that supplied the canyon with sediment. Truncation and erosion of the canyon-fill and fan facies of the late Paleocene-early Eocene Meganos Formation along the Diablo outcrop belt was primarily due to the major early middle Eocene lowstand (49.5 Ma).

  5. EXPECTED EFFECTS OF RESIDUAL CHLORINE AND NITROGEN IN SEWAGE EFFLUENT ON THE ESTUARINE ECOSYSTEM OF GREENWICH COVE, RI: AN ENERGY SYSTEMS AND RISK ASSESSMENT OF EFFECTS

    EPA Science Inventory

    Physical, toxicological, and energy systems modeling were combined to make estimates of likely ecosystem-level effects due to residual chlorine in sewage effluent. The energy systems model also allowed us to make estimates of the effects of nutrient loading on the estuary both se...

  6. EXPECTED EFFECTS OF RESIDUAL CHLORINE AND NITROGEN IN SEWAGE EFFLUENT ON THE ESTUARINE ECOSYSTEM OF GREENWICH COVE, RI: AN ENERGY SYSTEMS AND RISK ASSESSMENT OF EFFECTS

    EPA Science Inventory

    Physical, toxicological, and energy systems modeling were combined to make estimates of likely ecosystem-level effects due to residual chlorine in sewage effluent. The energy systems model also allowed us to make estimates of the effects of nutrient loading on the estuary both se...

  7. The live bird market system and low-pathogenic avian influenza prevention in southern California.

    PubMed

    Yee, Karen S; Carpenter, Tim E; Mize, Sarah; Cardona, Carol J

    2008-06-01

    Although live bird markets (LBMs) have been associated with outbreaks of avian influenza (AI), there are some LBM systems where AI outbreaks are extremely rare events. The California LBMs have not had any detected avian influenza viruses (AIVs) since December 2005. Responses to a detailed questionnaire on the practices and characteristics of the participants in the California low-pathogenic (LP) AI control program have been described to characterize possible reasons for the lack of AI outbreaks in LBMs. Compliance with an LPAI control program that contains active surveillance, prevention, and rapid response measures by those involved in the LBM system, rendering services to dispose of carcasses, no wholesalers, and few third-party bird deliveries was associated with the lack of LPAIV circulating in the Southern California LBM system.

  8. Defense Coastal/Estuarine Research Program (DCERP)

    DTIC Science & Technology

    2007-09-19

    foxes, raccoons, feral cats ) has been demonstrated to often be the most important factor affecting shorebird productivity, survival, and distribution... impacts - maritime forest Coastal Barrier 1. Survey biodiversity of maritime forests. Defense Coastal/Estuarine Research Program (DCERP...young of these species is predation by meso-predators, such as foxes and feral cats . The importance of predation on reproductive success of shorebirds

  9. Marine and estuarine protection: Programs and activities

    SciTech Connect

    Not Available

    1989-02-01

    The booklet describes: the mission of the current problems and threats to the coastal and marine waters of the US; the Office of Marine and Estuarine Protection of EPA; EPA's ocean dumping and plastics programs; EPA's point source control activities; near-coastal waters activities; and associated federal legislation.

  10. Estuarine Oceanography. CEGS Programs Publication Number 18.

    ERIC Educational Resources Information Center

    Wright, F. F.

    Estuarine Oceanography is one in a series of single-topic problem modules intended for use in undergraduate and earth science courses. Designed for those interested in coastal oceanography or limnology, the module is structured as a laboratory supplement for undergraduate college classes but should be useful at all levels. The module has two…

  11. Late Holocene estuarine-inner shelf interactions; is there evidence of an estuarine retreat path for Tampa Bay, Florida?

    USGS Publications Warehouse

    Donahue, B.T.; Hine, A.C.; Tebbens, S.; Locker, S.D.; Twichell, D.C.

    2003-01-01

    The purpose of this study was to determine if and how a large, modern estuarine system, situated in the middle of an ancient carbonate platform, has affected its adjacent inner shelf both in the past during the last, post-glacial sea-level rise and during the present. An additional purpose was to determine if and how this inner shelf seaward of a major estuary differed from the inner shelves located just to the north and south but seaward of barrier-island shorelines. Through side-scan sonar mosaicking, bathymetric studies, and ground-truthing using surface grab samples as well as diver observations, two large submarine sand plains were mapped - one being the modern ebb-tidal delta and the other interpreted to be a relict ebb-tidal delta formed earlier in the Holocene. The most seaward portion of the inner shelf studied consists of a field of lobate, bathymetrically elevated, fine-sand accumulations, which were interpreted to be sediment-starved 3D dunes surrounded by small 2D dunes composed of coarse molluscan shell gravel. Additionally, exposed limestone hardbottoms supporting living benthic communities were found as well. This modern shelf sedimentary environment is situated on a large, buried shelf valley, which extends eastward beneath the modern Tampa Bay estuary. These observations plus the absence of an incised shelf valley having surficial bathymetric expression, and the absence of sand bodies normally associated with back-tracking estuarine systems indicate that there was no cross-shelf estuarine retreat path formed during the last rise in sea level. Instead, the modern Tampa Bay formed within a mid-platform, low-relief depression, which was flooded by rising marine waters late in the Holocene. With continued sea-level rise in the late Holocene, this early embayment was translated eastward or landward to its present position, whereby a larger ebb-tidal delta prograded out onto the inner shelf. Extensive linear sand ridges, common to the inner shelves to

  12. Transport of persistent organic pollutants by microplastics in estuarine conditions

    NASA Astrophysics Data System (ADS)

    Bakir, Adil; Rowland, Steven J.; Thompson, Richard C.

    2014-03-01

    Microplastics represent an increasing source of anthropogenic contamination in aquatic environments, where they may also act as scavengers and transporters of persistent organic pollutants. As estuaries are amongst the most productive aquatic systems, it is important to understand sorption behaviour and transport of persistent organic pollutants (POPs) by microplastics along estuarine gradients. The effects of salinity sorption equilibrium kinetics on the distribution coefficients (Kd) of phenanthrene (Phe) and 4,4‧-DDT, onto polyvinyl chloride (PVC) and onto polyethylene (PE) were therefore investigated. A salinity gradient representing freshwater, estuarine and marine conditions, with salinities corresponding to 0 (MilliQ water, 690 μS/cm), 8.8, 17.5, 26.3 and 35 was used. Salinity had no significant effect on the time required to reach equilibrium onto PVC or PE and neither did it affect desorption rates of contaminants from plastics. Although salinity had no effect on sorption capacity of Phe onto plastics, a slight decrease in sorption capacity was observed for DDT with salinity. Salinity had little effect on sorption behaviour and POP/plastic combination was shown to be a more important factor. Transport of Phe and DDT from riverine to brackish and marine waters by plastic is therefore likely to be much more dependent on the aqueous POP concentration than on salinity. The physical characteristics of the polymer and local environmental conditions (e.g. plastic density, particle residence time in estuaries) will affect the physical transport of contaminated plastics. A transport model of POPs by microplastics under estuarine conditions is proposed. Transport of Phe and DDT by PVC and PE from fresh and brackish water toward fully marine conditions was the most likely net direction for contaminant transport and followed the order: Phe-PE >> DDT-PVC = DDT-PE >> Phe-PVC.

  13. The ionization of acids in estuarine waters

    NASA Astrophysics Data System (ADS)

    Millero, Frank J.

    1981-11-01

    The stoichiometric, K HA∗, and apparent, K' HA, constants for the ionization of a number of weak acids (NH 4+, HSO 4-, HF, H 2O, B(OH) 3, H 2CO 3, HCO 3-, H 3PO 4, H 2PO 4-, HPO 42, H 3AsO 4 H 2AsO 4- and HAsO 42-) in seawater at 25°C diluted with water have been fitted to equations of the form ( MILLERO, 1979). In K HA∗ = In K HA + AS 1/2 + BS where In KHA is the thermodynamic constant in water, S is the salinity, A and B are adjustable parameters. The validity of this equation in estuarine waters has been examined by using an ion pairing model ( MILLERO and SCHREIBER, 1981). The calculated values of K HA∗ and K' HA at S = 35%. are in good agreement with the measured values for all the systems examined. The equation used to extrapolate the measured values to pure water KHA predicted values that agreed with those determined by using the ion pairing model. The exception was the ionization of HPO 42- due to the strong interactions of Ca 2+ and Mg 2+ with PO 43-. The differences in the predicted values of K HA∗ in seawater diluted with pure water and average river water were very small for all the acids except HPO 42- (the maximum ΔpK = 0.96 in average river water). The larger difference in the K HA∗ for HPO 42- in river waters is due to the strong interactions of Ca 2+ and PO 43-.

  14. Estuarine mixing behavior of colloidal organic carbon and colloidal mercury in Galveston Bay, Texas.

    PubMed

    Lee, Seyong; Han, Seunghee; Gill, Gary A

    2011-06-01

    Mercury (Hg) in estuarine water is distributed among different physical phases (i.e. particulate, colloidal, and truly dissolved). This phase speciation influences the fate and cycling of Hg in estuarine systems. However, limited information exists on the estuarine distribution of colloidal phase Hg, mainly due to the technical difficulties involved in measuring it. In the present study, we determined Hg and organic carbon levels from unfiltered, filtered (<0.45 μm), colloidal (10 kDa-0.45 μm), and truly dissolved (<10 kDa) fractions of Galveston Bay surface water in order to understand the estuarine mixing behavior of Hg species as well as interactions of Hg with colloidal organic matter. For the riverine end-member, the colloidal fraction comprised 43 ± 11% of the total dissolved Hg pool and decreased to 17 ± 8% in brackish water. In the estuarine mixing zone, dissolved Hg and colloidal organic carbon showed non-conservative removal behavior, particularly in the low salinity (<15 ppt) region. This removal may be caused by salt-induced coagulation of colloidal matter and consequent removal of dissolved Hg. The particle-water interaction, K(d) ([particulate Hg (mol kg(-1))]/[dissolved Hg (mol L(-1))]) of Hg decreased as particle concentration increased, while the particle-water partition coefficient based on colloidal Hg and the truly dissolved Hg fraction, K(c) ([colloidal Hg (mol kg(-1))]/[truly dissolved Hg (mol L(-1))]) of Hg remained constant as particle concentration increased. This suggests that the particle concentration effect is associated with the amount of colloidal Hg, increasing in proportion to the amount of suspended particulate matter. This work demonstrates that, colloidal organic matter plays an important role in the transport, particle-water partitioning, and removal of dissolved Hg in estuarine waters.

  15. Using stable isotopes and models to explore estuarine linkages at multiple scales

    EPA Science Inventory

    Estuarine managers need tools to respond to dynamic stressors that occur in three linked environments – coastal ocean, estuaries and watersheds. Models have been the tool of choice for examining these dynamic systems because they simplify processes and integrate over multiple sc...

  16. Using stable isotopes and models to explore estuarine linkages at multiple scales

    EPA Science Inventory

    Estuarine managers need tools to respond to dynamic stressors that occur in three linked environments – coastal ocean, estuaries and watersheds. Models have been the tool of choice for examining these dynamic systems because they simplify processes and integrate over multiple sc...

  17. A Comparative Ecological Approach to Assess the Role of Watersheds in Estuarine Condition

    EPA Science Inventory

    Estuarine condition is a function of the geophysical nature of the estuary, the ocean (and atmospheric) system, and the upstream watershed. To fully understand and predict how an estuary will respond to a mixture of natural and anthropogenic drivers and pressures each compartment...

  18. The Role of Watershed Characteristics in Estuarine Condition: An Empirical Approach

    EPA Science Inventory

    Estuarine condition is a function of the nature of the estuary, ocean, and atmospheric systems, and the upstream watershed. To fully understand and predict how an estuary will respond to drivers and pressures, each compartment must be characterized. For example, eutrophication ef...

  19. Comparative Ecological Approach to Assess the Role of Watersheds in Estuarine Condition

    EPA Science Inventory

    Estuarine condition is a function of the nature of the estuary, ocean, and atmospheric systems, and the upstream watershed. To fully understand and predict how an estuary will respond to drivers and pressures, each compartment must be characterized. For example, eutrophication ef...

  20. Comparative Ecological Approach to Assess the Role of Watersheds in Estuarine Condition

    EPA Science Inventory

    Estuarine condition is a function of the nature of the estuary, ocean, and atmospheric systems, and the upstream watershed. To fully understand and predict how an estuary will respond to drivers and pressures, each compartment must be characterized. For example, eutrophication ef...

  1. A Comparative Ecological Approach to Assess the Role of Watersheds in Estuarine Condition

    EPA Science Inventory

    Estuarine condition is a function of the geophysical nature of the estuary, the ocean (and atmospheric) system, and the upstream watershed. To fully understand and predict how an estuary will respond to a mixture of natural and anthropogenic drivers and pressures each compartment...

  2. The Role of Watershed Characteristics in Estuarine Condition: An Empirical Approach

    EPA Science Inventory

    Estuarine condition is a function of the nature of the estuary, ocean, and atmospheric systems, and the upstream watershed. To fully understand and predict how an estuary will respond to drivers and pressures, each compartment must be characterized. For example, eutrophication ef...

  3. STRONG SELECTIVE SIGNAL AND HIGH GENETIC VARIABILITY AT AN IMMUNE SYSTEM LOCUS IN CONTAMINATED AND UNCONTAMINATED POPULATIONS OF AN ESTUARINE FISH

    EPA Science Inventory

    The major histocompatibility complex (MHC) is a group of linked genes that mediates the adaptive immune response in vertebrates. Studies using mammals and birds have shown that environmental stressors can produce genetic changes at MHC loci that can affect immune system function....

  4. STRONG SELECTIVE SIGNAL AND HIGH GENETIC VARIABILITY AT AN IMMUNE SYSTEM LOCUS IN CONTAMINATED AND UNCONTAMINATED POPULATIONS OF AN ESTUARINE FISH

    EPA Science Inventory

    The major histocompatibility complex (MHC) is a group of linked genes that mediates the adaptive immune response in vertebrates. Studies using mammals and birds have shown that environmental stressors can produce genetic changes at MHC loci that can affect immune system function....

  5. Water resources of the Southern Hills regional aquifer system, southeastern Louisiana

    USGS Publications Warehouse

    White, Vincent E.

    2017-03-01

    Information concerning the availability, use, and quality of groundwater in the 10 parishes overlying the Southern Hills regional aquifer system of Louisiana (fig. 1) is critical for water-supply management. The purpose of this fact sheet is to present information that can be used by water managers, residents, and others for stewardship of this vital resource. Information on the availability, past and current use, use trends, and water quality from groundwater sources in these parishes is presented. Previously published reports (see References Cited section) and data stored in the U.S. Geological Survey’s National Water Information System (U.S. Geological Survey, 2017) are the primary sources of the information presented here.

  6. Simulating effects of highway embankments on estuarine circulation

    USGS Publications Warehouse

    Lee, Jonathan K.; Schaffranek, Raymond W.; Baltzer, Robert A.

    1994-01-01

    A two-dimensional depth-averaged, finite-difference, numerical model was used to simulate tidal circulation and mass transport in the Port Royal Sound. South Carolina, estuarine system. The purpose of the study was to demonstrate the utility of the Surface-Water. Integrated. Flow and Transport model (SWIFT2D) for evaluating changes in circulation patterns and mass transport caused by highway-crossing embankments. A model of subregion of Port Royal Sound including the highway crossings and having a grid size of 61 m (200ft) was derived from a 183-m (600-ft) model of the entire Port Royal Sound estuarine system. The 183-m model was used to compute boundary-value data for the 61-m submodel, which was then used to simulate flow conditions with and without the highway embankments in place. The numerical simulations show that, with the highway embankment in place, mass transport between the Broad River and Battery Creek is reduced and mass transport between the Beaufort River and Battery Creek is increased. The net result is that mass transport into and out of upper Battery Creek is reduced. The presence of the embankments also alters circulation patterns within Battery Creek.

  7. Large Scale Landslide Database System Established for the Reservoirs in Southern Taiwan

    NASA Astrophysics Data System (ADS)

    Tsai, Tsai-Tsung; Tsai, Kuang-Jung; Shieh, Chjeng-Lun

    2017-04-01

    Typhoon Morakot seriously attack southern Taiwan awaken the public awareness of large scale landslide disasters. Large scale landslide disasters produce large quantity of sediment due to negative effects on the operating functions of reservoirs. In order to reduce the risk of these disasters within the study area, the establishment of a database for hazard mitigation / disaster prevention is necessary. Real time data and numerous archives of engineering data, environment information, photo, and video, will not only help people make appropriate decisions, but also bring the biggest concern for people to process and value added. The study tried to define some basic data formats / standards from collected various types of data about these reservoirs and then provide a management platform based on these formats / standards. Meanwhile, in order to satisfy the practicality and convenience, the large scale landslide disasters database system is built both provide and receive information abilities, which user can use this large scale landslide disasters database system on different type of devices. IT technology progressed extreme quick, the most modern system might be out of date anytime. In order to provide long term service, the system reserved the possibility of user define data format /standard and user define system structure. The system established by this study was based on HTML5 standard language, and use the responsive web design technology. This will make user can easily handle and develop this large scale landslide disasters database system.

  8. Winnowing and Flocculation in Bio-physical Cohesive Substrate: A Flume Experimental and Estuarine Study

    NASA Astrophysics Data System (ADS)

    Ye, L.; Parsons, D. R.; Manning, A. J.

    2016-12-01

    Cohesive sediment, or mud, is ubiquitously found in most aqueous environments, such as coasts and estuaries. The study of cohesive sediment behaviors requires the synchronous description of mutual interactions of grains (e.g., winnowing and flocculation), their physical properties (e.g., grain size) and also the ambient water. Herein, a series of flume experiments (14 runs) with different substrate mixtures of sand-clay-EPS (Extracellular Polymeric Substrates: secreted by aquatic microorganisms) are combined with an estuarine field survey (Dee estuary, NW England) to investigate the behavior of suspensions over bio-physical cohesive substrates. The experimental results indicate that winnowing and flocculation occur pervasively in bio-physical cohesive flow systems. Importantly however, the evolution of the bed and bedform dynamics and hence turbulence production can be lower when cohesivity is high. The estuarine survey also revealed that the bio-physical cohesion provided by both the clay and microorganism fractions in the bed, that pervasively exists in many natural estuarine systems, plays a significant role in controlling the interactions between bed substrate and sediment suspension and deposition, including controlling processes such as sediment winnowing, flocculation and re-deposition. Full understanding of these processes are essential in advancing sediment transport modelling and prediction studies across natural estuarine systems and the work will report on an improved conceptual model for sediment sorting deposition in bio-physical cohesive substrates.

  9. Sorghum and legume intercropping to improve resource use efficiency of forage production systems in the Southern High Plains

    USDA-ARS?s Scientific Manuscript database

    Declining water resources and the presence of large dairy and beef facilities in the Southern High Plains necessitates improving efficiency of forage production system to sustain irrigated agriculture in the region. Delayed inhabitance of interrow space by annual row cropping systems leads to ineffi...

  10. The Trophic Contributions of Rotifers in Tidal Freshwater and Estuarine Habitats

    NASA Astrophysics Data System (ADS)

    Park, G. S.; Marshall, H. G.

    2000-12-01

    Distribution patterns and trophic contributions of rotifers from freshwater through polyhaline estuarine waters were examined in the southern Chesapeake Bay and its major tributaries for a two-year period. Trichocerca marina and Synchaeta spp. were the major taxa in abundance, followed by Polyarthra vulgaris, Keratella cochlearis and Brachionus spp. There was a significant negative correlation between salinity and rotifer density, biomass, and number of species. Rotifers were a component of the microzooplankton biomass during specific periods and at particular sites, dominating summer assemblages in tidal freshwater and river-estuary transition sites, plus the winter communities in estuarine waters. This observation indicates that rotifers may play an important trophic role by seasonally replacing metazoan nauplii as a biomass source in both tidal freshwater and estuarine ecosystems. The annual contribution of rotifers to the total microzooplankton biomass exclusive of heterotrophic dinoflagellates was brief but intensive, achieving over 50% of annual biomass during a 2-3 month period. Despite the small annual mean contribution of rotifers to the total microzooplankton biomass, rotifers may have a limited, but significant impact on the trophic dynamics of the zooplankton community in Chesapeake Bay and its major tidal tributaries.

  11. Hydrological mixing and geochemical processes characterization in an estuarine/mangrove system using environmental tracers in Babitonga Bay (Santa Catarina, Brazil)

    NASA Astrophysics Data System (ADS)

    Barros Grace, Virgínia; Mas-Pla, Josep; Oliveira Novais, Therezinha; Sacchi, Elisa; Zuppi, Gian Maria

    2008-03-01

    The hydrologic complex of Babitonga Bay (Brazil) forms a vast environmental complex where agriculture, shellfish farming, and industries coexist with a unique natural area of Atlantic rain forest and mangrove systems. The origin of different continental hydrological components, the environmental transition between saline and freshwaters, and the influence of the seasonality on Babitonga Bay waters are evaluated using isotopes and chemistry. End-member mixing analysis is used to explore hydrological processes in the bay. We show that a mixing of waters from different origins takes place in the bay modifying its chemical characteristics. Furthermore, biogeochemical processes related to well-developed mangrove systems are responsible for an efficient bromide uptake, which limit its use as a tracer as commonly used in non-biologically active environments. Seasonal behaviours are also distinguished from our datasets. The rainy season (April) provides a homogenization of the hydrological processes that is not seen after the dry season (October), when larger spatial differences appear and when the effects of biological processes on the bay hydrochemistry are more dynamic, or can be better recognized. Moreover, Cl/Br and stable isotopes of water molecule allow a neat definition of the hydrological and biogeochemical processes that control chemical composition in coastal and transition areas.

  12. Temporally intensive study of trace metals in sediments and bivalves from a large river-estuarine system: Suisun Bay/delta in San Francisco Bay

    USGS Publications Warehouse

    Luoma, S.N.; Dagovitz, R.; Axtmann, E.

    1990-01-01

    Distributions in time and space of Ag, Cd, Cr, Cu, Pb and Zn were determined in fine-grained sediments and in the filter-feeding bivalve Corbicula sp. of Suisun Bay/delta at the mouth of the Sacramento and San Joaquin Rivers in North San Francisco Bay. Samples were collected from seven stations at near-monthly intervals for 3 years. Aggregated data showed little chronic contamination with Ag, Zn and Pb in the river and estuary. Substantial chronic contamination with Cd, Cu and Cr in Suisun Bay/delta occurred, especially in Corbicula, compared with the lower San Joaquin River. Salinity appeared to have secondary effects, if any, on metal concentrations in sediments and metal bioavailability to bivalves. Space/time distributions of Cr were controlled by releases from a local industry. Analyses of time series suggested substantial inputs of Cu might originate from the Sacramento River during high inflows to the Bay, and Cd contamination had both riverine and local sources. Concentrations of metals in sediments correlated with concentrations in Corbicula only in annually or 3-year aggregated data. Condition index for Corbicula was reduced where metal contamination was most severe. The biological availability of Cu and Cd to benthos was greater in Suisun Bay than in many other estuaries. Thus small inputs into this system could have greater impacts than might occur elsewhere; and organisms were generally more sensitive indicators of enrichment than sediments in this system.

  13. Temporally intensive study of trace metals in sediments and bivalves from a large river-estuarine system: Suisun Bay/Delta in San Francisco Bay.

    PubMed

    Luoma, S N; Dagovitz, R; Axtmann, E

    1990-11-01

    Distributions in time and space of Ag, Cd, Cr, Cu, Pb and Zn were determined in fine-grained sediments and in the filter-feeding bivalve Corbicula sp. of Suisun Bay/delta at the mouth of the Sacramento and San Joaquin Rivers in North San Francisco Bay. Samples were collected from seven stations at near-monthly intervals for 3 years. Aggregated data showed little chronic contamination with Ag, Zn and Pb in the river and estuary. Substantial chronic contamination with Cd, Cu and Cr in Suisun Bay/delta occurred, especially in Corbicula, compared with the lower San Joaquin River. Salinity appeared to have secondary effects, if any, on metal concentrations in sediments and metal bioavailability to bivalves. Space/time distributions of Cr were controlled by releases from a local industry. Analyses of time series suggested substantial inputs of Cu might originate from the Sacramento River during high inflows to the Bay, and Cd contamination had both riverine and local sources. Concentrations of metals in sediments correlated with concentrations in Corbicula only in annually or 3-year aggregated data. Condition index for Corbicula was reduced where metal contamination was most severe. The biological availability of Cu and Cd to benthos was greater in Suisun Bay than in many other estuaries. Thus small inputs into this system could have greater impacts than might occur elsewhere; and organisms were generally more sensitive indicators of enrichment than sediments in this system.

  14. Mesoscale simulations of convective systems with data assimilation during June 1993 in the Southern Great Plains

    SciTech Connect

    Dudhia, J.

    1995-04-01

    An intensive observation period (IOP) took place at the Southern Great Plains Cloud and Radiation Testbed (CART) site from June 16-26,1993. Additional observations came from two integrated sounding systems (ISSs) and three National Center for Atmospheric Research (NCAR) cross-chain loran atmospheric sounding system (CLASS) sites to complement the central CART site and the seven National Weather Service (NWS) profilers of the demonstration network in the area. The NCAR/Penn State Mesoscale Model (MM5) has been used to simulate this period on a 60-km domain with 20- and 6.67-km nests centered on Lamont, Oklahoma. Simulations are being run with data assimilated by the nudging technique to incorporate upper-air and surface data from a variety of platforms. One goal of this work is to use all the available data collected in the Southern Great Plains CART area in conjunction with a continuously running mesoscale model to provide complete hourly datasets of the wind, temperature, humidity, and cloud distributions at high resolution. The model maintains dynamical consistency between the fields, while the data correct for model biases that may occur during long-term simulations and provide boundary conditions. In this study the feasibility of driving the model with surface data, rawinsonde data, profiler winds, microwave radiometer moisture data, and radio-acoustic sounding system (RASS) temperatures is being demonstrated. The dataset provided will be a valuable resource for comparison with general circulation model (GCM) parameterizations of cloud and radiation fields, as well as for mesoscale studies of convective events during this period.

  15. Improving the seismic imaging in the southern Ryukyu subduction system by using multiple attenuation methods

    NASA Astrophysics Data System (ADS)

    Lyu, Ci-Jhu; Kuo-Chen, Hao; McIntosh, Kirk; Wu, Francis; Liu, Char-Shine

    2015-04-01

    The southern Ryukyu subduction system is at the boundary where the Philippine sea plate subducts northwestward beneath the Eurasian plate near the Taiwan orogen. In previous studies, the boundary where the PSP subducts northward beneath the EP have no clear answers due to a lack of high-resolution crustal-scale geophysical constraints. We want to know the Moho boundary. We analyze in this study the dynamics of SRA system with TAIGER program of 2009, multi-channel marine seismic reflection (MGL0906_23, MGL0906_28, MGL0906_26A, MGL0906_13, MGL0906_18N). Data area covers about 30,000 km2. Shots are spaced every 50 m, hydrophones are spaced every 12.5 m, and CDP spacing is 6.25 m. Recording length is 15 s. Signal of the source is low frequencies (20Hz~60Hz), which can penetrate the shallow sediments and reflex signal of the deep crust. Because multiple can affect the deep structure signals. Therefore, we use a variety of methods to remove multiple effects, and increase Moho signals. In this study, we use four ways to remove the multiple. (1) Increases CDP spacing. (2)Deconvolution. (3) Surface Related Multiple Elimination (SRME). (4)Radon Transform multiple attenuation. From the TAIGER marine reflection data. The shallow structure are Huatung Basin, Yeyama Accretionary Prism, Forearc Basin and Ryukyu Arc (from south to north), respectively. We discover a lot of transform fault zone, and account these stress related with shear zone of Ryukyu subduction system. The deep structure, the crust of PSP velocity is about 5~7 km/s, the PSP Moho velocity is 7.5 km/s. In multichannel reflection seismic, the PSP Moho deep is about 15~20 km under the seabed. Keywords: multiple; Moho boundary; subduction zone; southern Ryukyu Arc (SRA)

  16. Eddy surface properties and propagation at Southern Hemisphere western boundary current systems

    NASA Astrophysics Data System (ADS)

    Pilo, G. S.; Mata, M. M.; Azevedo, J. L. L.

    2015-08-01

    Oceanic eddies exist throughout the world oceans, but are more energetic when associated with western boundary currents (WBC) systems. In these regions, eddies play an important role in mixing and energy exchange. Therefore, it is important to quantify and qualify eddies associated with these systems. This is particularly true for the Southern Hemisphere WBC system where only few eddy censuses have been performed to date. In these systems, important aspects of the local eddy population are still unknown, like their spatial distribution and propagation patterns. Moreover, the understanding of these patterns helps to establish monitoring programs and to gain insight in how eddies would affect local mixing. Here, we use a global eddy data set to qualify eddies based on their surface characteristics in the Agulhas Current (AC), the Brazil Current (BC) and the East Australian Current (EAC) systems. The analyses reveal that eddy propagation within each system is highly forced by the local mean flow and bathymetry. Large values of eddy amplitude and temporal variability are associated with the BC and EAC retroflections, while small values occur in the centre of the Argentine Basin and in the Tasman Sea. In the AC system, eddy polarity dictates the propagation distance. BC system eddies do not propagate beyond the Argentine Basin, and are advected by the local ocean circulation. EAC system eddies from both polarities cross south of Tasmania but only the anticyclonic ones reach the Great Australian Bight. For all three WBC systems, both cyclonic and anticyclonic eddies present a geographical segregation according to radius size and amplitude. Regions of high eddy kinetic energy are associated with the eddies' mean amplitudes, and not with their densities.

  17. Uranium content and dose assessment for sediment and soil samples from the estuarine system of Santos and Sao Vicente, SP, Brazil.

    PubMed

    Geraldo, L P; Serafim, R A M; Corrêa, B A M; Yamazaki, I M; Primi, M C

    2010-06-01

    In this work, the uranium (U) content in sediment and soil samples collected near the Santos and São Vicente estuaries was determined using the fission track registration technique (SSNTD). The sediment and soil samples after oven-dried and pulverised were prepared in the solution form. About 10 microl of this solution was deposited on a plastic detector and irradiated at the IPEN-IEA-R1 (3.5 MW) nuclear reactor. After the irradiation and chemical etching of the plastic foils, the fission tracks were counted with a system consisting of an optical microscope together with a video camera and a PC. The U content in the analysed samples ranged from 3.12 +/- 0.55 to 18.3 +/- 1.2 ppm for sediments and from 3.21 +/- 0.63 to 11.5 +/- 1.1 ppm for soils or in terms of (238)U equivalent activity from 38.5 +/- 6.8 to 226 +/- 15 and 39.6 +/- 7.8 to 142 +/- 14 Bq kg(-1) for sediments and soils, respectively. These results were compared with other values reported in the literature for sediments and soils collected in environments similar to the ones studied in this work. Most of the values obtained in this work are higher than the world mean and are in reasonable agreement with results found by other authors for sediments and soils from regions considered as polluted or with a high level of radioactivity.

  18. Movement of spilled oil as predicted by estuarine nontidal drift

    USGS Publications Warehouse

    Conomos, T.J.

    1975-01-01

    Information on water movement obtained from bimonthly releases of surface and seabed drifters in the San Francisco Bay and adjacent Pacific Ocean is used to understand major processes controlling dispersal of oil after a spill of 3,200 m3 of Bunker C in the bay in January 1971. River-induced nontidal estuarine circulation was the dominant factor controlling net movement of the oil spilled at the entrance of the bay system, reinforcing ebbing tidal currents and causing the seaward movement of floating oil, which followed paths taken by surface drifters released 3 weeks before the spill. In contrast, some oil formed globules which sank to the near-bottom waters, had the same relative buoyancy as seabed drifters, and moved similarly, beaching in eastern San Pablo Bay after being transported landward in the near-bottom waters. No oil or surface drifters floated into the south bay because surface waters were drifting seaward, away from the south bay. Notable seasonally modulated phenomena which must be considered in predicting surface and near-bottom oil drifts of future spills include a summer (low-river discharge period) diminution of the estuarine circulation mechanism in the north and central bayadjacent ocean region and a seasonal reversal in two-layer drift in the south bay.

  19. Towards Sustainable Water Quality In Estuarine Impoundments: Sediment Processes.

    NASA Astrophysics Data System (ADS)

    Wright, J.; Worrall, F.

    Several estuarine impoundment schemes have been built or are proposed in the UK and worldwide. The impounding of estuaries is currently a popular approach to urban regeneration in the UK. By creation of an aesthetically pleasing amenity impound- ment, including the drowning of "unsightly" tidal mud flats, it is hoped that prestige development will be encouraged in the estuarine area. Impounding fundamentally alters the dynamics of estuaries, with consequences in terms of sedimentation patterns and rates, and water quality. The SIMBA Project at- tempts to understand the controls on water quality in impoundments, with a view to- wards long term and sustainable high water quality through good barrage design and management practice. The results of process based studies, concentrating on interactions between sediment and water quality in the systems, are presented. A series of sequential extraction exper- iments have been carried out on cores of sediment to model the releases from sediment under different environmental conditions likely to be encountered in the impound- ments. Results are related to similar experiments carried out on suspended particulate material, and to pore-water experiments carried out using gel-probes.

  20. The role of nutrient loading and eutrophication in estuarine ecology.

    PubMed Central

    Pinckney, J L; Paerl, H W; Tester, P; Richardson, T L

    2001-01-01

    Eutrophication is a process that can be defined as an increase in the rate of supply of organic matter (OM) to an ecosystem. We provide a general overview of the major features driving estuarine eutrophication and outline some of the consequences of that process. The main chemical constituent of OM is carbon (C), and therefore rates of eutrophication are expressed in units of C per area per unit time. OM occurs in both particulate and dissolved forms. Allochthonous OM originates outside the estuary, whereas autochthonous OM is generated within the system, mostly by primary producers or by benthic regeneration of OM. The supply rates of limiting nutrients regulate phytoplankton productivity that contributes to inputs of autochthonous OM. The trophic status of an estuary is often based on eutrophication rates and can be categorized as oligotrophic (<100 g C m(-2) y(-1), mesotrophic (100-300 g C m(-2) y(-1), eutrophic (300-500 g C m(-2) y(-1), or hypertrophic (>500 g C m(-2) y(-1). Ecosystem responses to eutrophication depend on both export rates (flushing, microbially mediated losses through respiration, and denitrification) and recycling/regeneration rates within the estuary. The mitigation of the effects of eutrophication involves the regulation of inorganic nutrient (primarily N and P) inputs into receiving waters. Appropriately scaled and parameterized nutrient and hydrologic controls are the only realistic options for controlling phytoplankton blooms, algal toxicity, and other symptoms of eutrophication in estuarine ecosystems. PMID:11677178

  1. Facies architecture in a tectonically influenced estuarine incised valley fill of Miocene age, northern Brazil

    NASA Astrophysics Data System (ADS)

    Rossetti, Dilce F.; Santos Júnior, Antônio E.

    2004-12-01

    The Miocene Barreiras Formation in the Middle Rio Capim area records an incised valley system for which facies analysis and ichnology ( Skolithos, Ophiomorpha, Planolites, Gyrolithes, Taenidium) suggest an estuarine character. Three stratigraphic units are recognized (from bottom to top): Unit 1 includes an inner estuarine tidal channel complex and tidal flat/salt marsh deposits; Unit 2 consists of estuarine bay/lagoon and flood tidal delta deposits related to the estuary mouth; and Unit 3 includes a tidal channel with a tidal point bar, as well as tidal flat/salt marsh deposits similar to those from Unit 1. These units and their bounding surfaces record the history of relative sea level changes in the estuary. After a sea level drop, the valley was inundated and formed an amalgamated sequence boundary and transgressive surface. Transgression (Unit 1) promoted the landward shift of flood tidal deltas and lagoon settings (Unit 2). The system then moved seaward, with the superposition of inner estuarine deposits (Unit 3) over Unit 2. Facies architecture seems to have been controlled by tectonics, as shown by: the paleovalley orientation according to the main tectonic structures of the basin; the presence of faults and fractures that displace the basal unconformity; and the abundance of soft sediment deformation.

  2. Intertidal macroalgae and macroinvertebrates: Seasonal and spatial abundance patterns along an estuarine gradient

    NASA Astrophysics Data System (ADS)

    Hardwick-Witman, Morgan N.; Mathieson, Arthur C.

    1983-02-01

    Quantitative sampling of the dominant intertidal epibiota was conducted seasonally along an estuarine gradient within the Great Bay Estuary System, New Hampshire, U.S.A. The abundance and zonation of the dominant macroorganisms varied with distance into the estuary. Replacement of marine by estuarine species occurred, and overall abundance and species richness decreased along the estuarine gradient. Zonation patterns within the inner estuary were primarily allied with substrata. Maximum abundance of invertebrates occurred in the mid-intertidal zone where a dense fucoid canopy provided habitat heterogeneity. Densities of epibiotic organisms decreased toward low water, especially in the inner estuary where hard substratum was limiting. Settlement blocks, introduced into the low intertidal zone, were dominated by barnacles and fucoid algae; after 16 months, the species composition on the settlement blocks resembled the adjacent community. Semibalanus balanoides settled in the spring, while Fucus vesiculosus var. spiralis exhibited low but constant settlement. Despite the physical rigors of the estuarine environment, only Semibalanus balanoides, Ilyanassa obsoleta and Spartina alterniflora showed significant seasonal changes in density. Thus, there are predictable and persistent epibiotic species assemblages within the intertidal zone of the Great Bay Estuary System.

  3. Economic crisis and inequalities in health systems in the countries of Southern Europe.

    PubMed

    Serapioni, Mauro

    2017-09-28

    The current article addresses the issue of health system inequalities in the countries of Southern Europe, specifically Spain, Greece, Italy, and Portugal. The study resulted from a non-systematic literature review, based on the scoping review proposal. We begin by presenting a brief contextualization of the social welfare state systems in these European countries, highlighting the principal specificities and differences in relation to other European welfare state systems. Next, we describe the health systems in the four countries, emphasizing the respective reform processes and the main health inequalities that have characterized them before and during the economic crisis. The crisis and austerity policies have greatly increased the level of dissatisfaction with healthcare provision in these countries, particularly in Greece and Portugal. In this sense, we conduct a comparative discussion of the health inequalities, identifying both common trends and differences. In the four countries, the social gradient (particularly in education, income, and labor) represents the principal determinant of health inequalities, while not ruling out geographic inequalities in access to health services as the result of different levels of economic development in the various regions. Finally, we discuss the recent debate in the international literature on the relationship between different welfare state systems and health inequalities, and precisely the critique of the use of welfare state typologies as a determinant of health and health inequalities.

  4. Seismometer deployment campaign and observations on the tectonics of the Southern Vienna basin fault system.

    NASA Astrophysics Data System (ADS)

    Le Bras, Ronan; Bianchi, Irene; Piana Agostinetti, Nicola; Bokelmann, Götz

    2014-05-01

    Two moderate size earthquakes (both M=4.2) shook the Vienna basin in September-October 2013. Immediately following the second earthquake on October 2, the Institute of Meteorology and Geophysics in Vienna (IMGW) deployed a three station local network located within a few kilometers of the fault zone with the aim to monitor the aftershocks and better understand the tectonics of the Vienna basin. We present the results of this data collection exercise and show some interesting observations at station SOP, located in Sopron, Hungary. The station is located close to the nodal plane for earthquakes on the Southern Vienna Basin fault system fault and data for the largest aftershocks in October 1-2 show a pattern indicating a progression of the rupture from the South-West to the North-East which can best be explained by rupture along the direction of the main fault.

  5. Physiochemical Evidence of Faulting Processes and Modeling of Fluid in Evolving Fault Systems in Southern California

    SciTech Connect

    Boles, James

    2013-05-24

    Our study targets recent (Plio-Pleistocene) faults and young (Tertiary) petroleum fields in southern California. Faults include the Refugio Fault in the Transverse Ranges, the Ellwood Fault in the Santa Barbara Channel, and most recently the Newport- Inglewood in the Los Angeles Basin. Subsurface core and tubing scale samples, outcrop samples, well logs, reservoir properties, pore pressures, fluid compositions, and published structural-seismic sections have been used to characterize the tectonic/diagenetic history of the faults. As part of the effort to understand the diagenetic processes within these fault zones, we have studied analogous processes of rapid carbonate precipitation (scaling) in petroleum reservoir tubing and manmade tunnels. From this, we have identified geochemical signatures in carbonate that characterize rapid CO2 degassing. These data provide constraints for finite element models that predict fluid pressures, multiphase flow patterns, rates and patterns of deformation, subsurface temperatures and heat flow, and geochemistry associated with large fault systems.

  6. The Impact of Solar Photovoltaic Generation on Balancing Requirements in the Southern Nevada System

    SciTech Connect

    Ma, Jian; Lu, Shuai; Hafen, Ryan P.; Etingov, Pavel V.; Makarov, Yuri V.; Chadliev, Vladimir

    2012-05-07

    Abstract—The impact of integrating large-scale solar photovoltaic (PV) generation on the balancing requirements in terms of regulation and load-following requirements in the southern Nevada balancing area is evaluated. The “swinging door” algorithm and the “probability box” method developed by Pacific Northwest National Laboratory (PNNL) were used to quantify the impact of large PV generation on the balancing requirements of the system operations. The system’s actual scheduling, real-time dispatch and regulation processes were simulated. Different levels of distributed generation were also considered in the study. The impact of hourly solar PV generation forecast errors on regulation and load-following requirements was assessed. The sensitivity of balancing requirements with respect to real-time forecast errors of large PV generation was analyzed. Index Terms—Ancillary services, balancing requirements, load following, regulation, renewables integration, swinging door

  7. Alternative nursery habitat for estuarine associated marine fish during prolonged closure of the St Lucia estuary, South Africa

    NASA Astrophysics Data System (ADS)

    Vivier, Leon; Cyrus, Digby P.

    2009-10-01

    The Mfolozi estuary, located on the east coast of South Africa, was historically directly linked to the adjacent St Lucia estuarine system, the largest estuarine system in Africa and a World Heritage Site. The Mfolozi used to be the main feeder system to maintain lake levels in St Lucia, but increased siltation from sugar cane farming in the Mfolozi floodplain led to artificial separation of the two systems in 1950. Reduced freshwater inflow due to drought conditions caused the St Lucia mouth to remain closed from June 2002 to present, coinciding with low lake levels and hypersaline conditions, except for a brief period during 2007 after the St Lucia mouth breached. These conditions led to disruption of larval recruitment into the system and major changes in biotic communities. Due to the importance of the St Lucia - Mfolozi System link, a study was initiated in 2007 on the fish community of the Mfolozi system, which was sampled using seine and gill nets. The 48 species recorded were dominated by juveniles of marine spawners, particularly Leiognathus equula and Valamugil cunnesius and the estuarine spawners Ambassis dussumieri and Ambassis natalensis. Estuarine dependent marine spawning species formed 68% of both the species numbers and CPUE, an indication of the regional importance of the Mfolozi estuary as an alternate refuge for juvenile marine fish during periods when the St Lucia system remained closed. Post-larval recruits of marine spawning species were particularly abundant, but low zoobenthic densities caused a rapid decline in numbers of benthic feeders shortly after their recruitment into the system. The importance of the Mfolozi estuary in maintaining marine brood stocks of estuarine dependent marine fish is discussed with particular reference to estuarine degradation and the ecological integrity of the St Lucia system.

  8. Estuarine turbidity, flushing, salinity, and circulation

    NASA Technical Reports Server (NTRS)

    Pritchard, D. W.

    1972-01-01

    The effects of estuarine turbidity, flushing, salinity, and circulation on the ecology of the Chesapeake Bay are discussed. The sources of fresh water, the variations in salinity, and the circulation patterns created by temperature and salinity changes are analyzed. The application of remote sensors for long term observation of water temperatures is described. The sources of sediment and the biological effects resulting from increased sediments and siltation are identified.

  9. Detrital diversity influences estuarine ecosystem performance.

    PubMed

    Kelaher, Brendan P; Bishop, Melanie J; Potts, Jaimie; Scanes, Peter; Skilbeck, Greg

    2013-06-01

    Global losses of seagrasses and mangroves, eutrophication-driven increases in ephemeral algae, and macrophyte invasions have impacted estuarine detrital resources. To understand the implications of these changes on benthic ecosystem processes, we tested the hypotheses that detrital source richness, mix identity, and biomass influence benthic primary production, metabolism, and nutrient fluxes. On an estuarine muddy sandflat, we manipulated the availability of eight detrital sources, including mangrove, seagrass, and invasive and native algal species that have undergone substantial changes in distribution. Mixes of these detrital sources were randomly assigned to one of 12 treatments and dried detrital material was added to seventy-two 0.25 m(2) plots (n = 6 plots). The treatments included combinations of either two or four detrital sources and high (60 g) or low (40 g) levels of enrichments. After 2 months, the dark, light, and net uptake of NH4 (+) , dissolved inorganic nitrogen, and the dark efflux of dissolved organic nitrogen were each significantly influenced by the identity of detrital mixes, rather than detrital source richness or biomass. However, gross and net primary productivity, average oxygen flux, and net NOX and dissolved inorganic phosphorous fluxes were significantly greater in treatments with low than with high detrital source richness. These results demonstrate that changes in detrital source richness and mix identity may be important drivers of estuarine ecosystem performance. Continued impacts to estuarine macrophytes may, therefore, further alter detritus-fueled productivity and processes in estuaries. Specific tests that address predicted future changes to detrital resources are required to determine the consequences of this significant environmental problem. © 2013 Blackwell Publishing Ltd.

  10. Long-term patterns in estuarine fish growth across two climatically divergent regions.

    PubMed

    Doubleday, Zoë A; Izzo, Christopher; Haddy, James A; Lyle, Jeremy M; Ye, Qifeng; Gillanders, Bronwyn M

    2015-12-01

    Long-term ecological datasets are vital for investigating how species respond to changes in their environment, yet there is a critical lack of such datasets from aquatic systems. We developed otolith growth 'chronologies' to reconstruct the growth history of a temperate estuarine fish species, black bream (Acanthopagrus butcheri). Chronologies represented two regions in south-east Australia: South Australia, characterised by a relatively warm, dry climate, and Tasmania, characterised by a relatively cool, wet climate. Using a mixed modelling approach, we related inter-annual growth variation to air temperature, rainfall, freshwater inflow (South Australia only), and El Niño-Southern Oscillation events. Otolith chronologies provided a continuous record of growth over a 13- and 21-year period for fish from South Australia and Tasmania, respectively. Even though fish from Tasmania were sourced across multiple estuaries, they showed higher levels of growth synchronicity across years, and greater year-to-year growth variation, than fish from South Australia, which were sourced from a single, large estuary. Growth in Tasmanian fish declined markedly over the time period studied and was negatively correlated to temperature. In contrast, growth in South Australian fish was positively correlated to both temperature and rainfall. The stark contrast between the two regions suggests that Tasmanian black bream populations are more responsive to regional scale environmental variation and may be more vulnerable to global warming. This study highlights the importance of examining species response to climate change at the intra-specific level and further validates the emerging use of growth chronologies for generating long-term ecological data in aquatic systems.

  11. Seasonal variability of estuarine dynamics due to freshwater discharge and its influence on biological productivity in Yeongsan River Estuary, Korea.

    PubMed

    Kim, Yong Hoon; Hong, Seongjin; Song, Yong Sik; Lee, Hyojin; Kim, Hae-Cheol; Ryu, Jongseong; Park, Jinsoon; Kwon, Bong-Oh; Lee, Chang-Hee; Khim, Jong Seong

    2017-08-01

    In order to evaluate water quality and biological productivity, observation data sets were collected and analyzed in Yeongsan River Estuary, Korea. We also set up a numerical model to resolve hydrodynamics and fate of water quality variables in the system. Results show that most of nutrients loading are trapped in the lake and higher concentrations of nutrients and organic matters (OM) are present only inside of the artificial sea dike. There exist episodial discharges at the dam, which coincide mostly with rainfall events during summer monsoon periods. During this discharge event, lower salinity and higher suspended solids, nutrients, and OM are observed in surface layer of the estuarine section. Hydrodynamic model results show that circulation in the estuarine section is governed by freshwater discharge from the lake, resulting in an enhanced two-layer estuarine circulation being dominated, during and after the freshwater is discharged. Such two-layer estuarine circulation combined with higher concentration of nutrients in the surface layer results in that outfluxes of nutrients in the surface layer dominate over the influxes in the bottom layer during summer high precipitation periods. Meanwhile, numerical dye experiment results show that the discharged water with elevated nutrients levels have a short residence time (∼5-10 days) in the estuarine section. Due to this fast flushing rate, excessive nutrient loadings are not used to produce biological matters in the estuarine section. This limited biological productivity, characterized by seaward side of the artificial sea dike, makes Yeongsan estuarine system excluded from acting as an active carbon sink. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Concentration of enteroviruses from estuarine water.

    PubMed

    Farrah, S R; Goyal, S M; Gerba, C P; Wallis, C; Melnick, J L

    1977-05-01

    Pleated cartridge filters readily adsorb viruses in estuarine water at low pH containing aluminum chloride. Adsorbed viruses are efficiently recovered by treating filters with glycine buffer at high pH. By using these procedures, it was possible to recover approximately 70% of the poliovirus added to 400 liters of estuarine water in 3 liters of filter eluate. Reconcentration of virus in the filter eluate in small volumes that are convenient for viral assays was more difficult. Reconcentration methods described previously for eluates from filters that process tap water or treated wastewater were inadequate when applied to eluates from filters used to process estuarine water containing large amounts of organic compounds. Two methods were found to permit efficient concentration of virus in filter eluates in small volumes. In both methods, virus in 3 liters of filter eluate was adsorbed to aluminum hydroxide flocs and then recovered in approximately 150 ml of buffered fetal calf serum. Additional reductions in volume were achieved by ultrafiltration or hydroextraction. By using these procedures 60 to 80% of the virus in 3 liters of filter eluate could be recovered in a final volume of 10 to 40 ml.

  13. Concentration of enteroviruses from estuarine water.

    PubMed Central

    Farrah, S R; Goyal, S M; Gerba, C P; Wallis, C; Melnick, J L

    1977-01-01

    Pleated cartridge filters readily adsorb viruses in estuarine water at low pH containing aluminum chloride. Adsorbed viruses are efficiently recovered by treating filters with glycine buffer at high pH. By using these procedures, it was possible to recover approximately 70% of the poliovirus added to 400 liters of estuarine water in 3 liters of filter eluate. Reconcentration of virus in the filter eluate in small volumes that are convenient for viral assays was more difficult. Reconcentration methods described previously for eluates from filters that process tap water or treated wastewater were inadequate when applied to eluates from filters used to process estuarine water containing large amounts of organic compounds. Two methods were found to permit efficient concentration of virus in filter eluates in small volumes. In both methods, virus in 3 liters of filter eluate was adsorbed to aluminum hydroxide flocs and then recovered in approximately 150 ml of buffered fetal calf serum. Additional reductions in volume were achieved by ultrafiltration or hydroextraction. By using these procedures 60 to 80% of the virus in 3 liters of filter eluate could be recovered in a final volume of 10 to 40 ml. PMID:18088

  14. Systemic implementation strategies to improve hypertension: the Kaiser Permanente Southern California experience.

    PubMed

    Sim, John J; Handler, Joel; Jacobsen, Steven J; Kanter, Michael H

    2014-05-01

    The past decade has seen hypertension improving in the United States where control is approximately 50%. Kaiser Permanente has mirrored and exceeded these national advances in control. Integrated models of care such as Kaiser Permanente and the Veterans Administration health systems have demonstrated the greatest hypertension outcomes. We detail the story of Kaiser Permanente Southern California (KPSC) to illustrate the success that can be achieved with an integrated health system model that uses implementation, dissemination, and performance feedback approaches to chronic disease care. KPSC, with a large ethnically diverse population of more than 3.6 million, has used a stepwise approach to achieve control rates greater than 85% in those recognized with hypertension. This was accomplished through systemic implementations of specific strategies: (1) capturing hypertensive members into a hypertension registry; (2) standardization of blood pressure measurements; (3) drafting and disseminating an internal treatment algorithm that is evidence-based and is advocating of combination therapy; and (4) a multidisciplinary approach using medical assistants, nurses, and pharmacists as key stakeholders. The infrastructure, support, and involvement across all levels of the health system with rapid and continuous performance feedback have been pivotal in ensuring the follow-through and maintenance of these strategies. The KPSC hypertension program is continually evolving in these areas. With these high control rates and established infrastructure, they are positioned to take on different innovations and study models. Such potential projects are drafting strategies on resistant hypertension or addressing the concerns about overtreatment of hypertension.

  15. Seismic anisotropy of the lithosphere/asthenosphere system beneath southern Madagascar

    NASA Astrophysics Data System (ADS)

    Reiss, M. C.; Rumpker, G.; Tilmann, F. J.; Yuan, X.; Rindraharisaona, E. J.

    2015-12-01

    Madagascar is considered as a key region with respect to the assembly and break-up of the supercontinent Gondwana. Following the collision between East- and West-Gondwana (~700-650 Ma), its position was central to the Pan-African orogeny and later to the break-up between East-Africa, India and Antarctica. Today, Madagascar consists of different tectonic units; the eastern two thirds of the island are composed mainly of Precambian rocks, whereas the western part is dominated by sedimentary deposits. Southern Madagascar is characterized by several NS to NW-SE trending shear zones. To increase our understanding of these structures and related tectonic processes, we installed a dense temporary seismic network in southern Madagascar. It consisted of 50 stations, which were in operation for up to 2 years between 2012 and 2014. We present results from shear-wave splitting analyses to infer the seismic anisotropy of the lithosphere-asthenosphere system in response to deformational processes. The polarization of the fast shear wave and the delay time between the fast and slow waves provide constraints on the anisotropic fabric. For our study, we use core phases from up to 22 events. We first apply a conventional single-event splitting analysis by minimizing the transverse component. For stations that do not show a significant azimuthal dependence of the splitting parameters, we also apply a joint inversion involving all recorded waveforms from several events. Our results exhibit delay times between 0.4 and 1.5 s. In the center of the E-W profile, fast axes are mainly oriented NNW-SSE, whereas east of the Ranotsara zone, fast axes are oriented NE-SW. We apply full-waveform FD modeling to examine the effects of various anisotropic models of the crust and mantle. Our results indicate that recently proposed mantle flow models are insufficient to explain the small scale variations of splitting parameters observed along our profile. Our observations are best characterized by

  16. Assessment of forest fragmentation in southern New England using remote sensing and geographic information systems technology

    USGS Publications Warehouse

    Vogelmann, James E.

    1995-01-01

    Spatial patterns and rates of forest fragmentation were assessed using digital remote sensing data for a region in southern New England that included 157 townships in southern New Hampshire and northeastern Massachusetts. The study area has undergone marked population increases over the last several decades. Following classification of 1973 and 1988 Landsat Multispectral Scanner data into forest and nonforest classes, data were incorporated into a geographic information system. The natural logarithms of forest area to perimeter ratios, referred to as the forest continuity index, were used to assess patterns and trends of forest fragmentation across the region Forest continuity index values were extracted from each township for both data sets and compared with population data. Forest continuity index values were found to decrease with increasing population density until about 200 persons per square kilometer, after which the relationship stabilized. With slight population increases at low densities forest continuity index values declined sharply, implying abrupt increases in forest fragmentation. Results from the study indicated good negative correlations (r2 values of 0.81 and 0.77) between the Multispectral Scanner-derived forest continuity index and natural logs of township population density. Socioeconomic indicators such as affluence and commuting patterns did not appear to correlate well with forest fragmentation estimates. Decreases in forest continuity index values occurred throughout much of the study region between 1973 and 1988, suggesting that forest fragmentation is occurring over large regions within the eastern United States. It is technologically feasible to assess patterns and rates of forest fragmentation across much larger areas than analyzed in this study; such analyses would provide useful overviews enabling objective assessment of the magnitude of forest fragmentation.

  17. Patterns in floral traits and plant breeding systems on Southern Ocean Islands

    PubMed Central

    Lord, Janice M.

    2015-01-01

    The harsh climatic conditions and paucity of potential pollinators on Southern Ocean Islands (SOIs; latitude 46°S–55°S) lead to the expectation that anemophily or self-fertilization are the dominant modes of plant sexual reproduction. However, at least some species have showy inflorescences suggesting biotic pollination or dimorphic breeding systems necessitating cross-pollination. This study investigates whether anemophily and self-compatibility are common on SOIs, whether species or genera with these traits are more widespread or frequent at higher latitudes, and whether gender dimorphy is correlated with anemophily, as might occur if reliance on pollinators was a disadvantage. Of the 321 flowering plant species in the SOI region, 34.3 % possessed floral traits consistent with anemophily. Compatibility information was located for 94 potentially self-fertilizing species, of which 92.6 % were recorded as partially or fully self-compatible. Dioecy occurred in 7.1 % of species overall and up to 10.2 % of island floras, but has not clearly arisen in situ. Gynodioecy occurred in 3.4 % of species. The frequency of anemophily and gender dimorphy did not differ between the SOI flora and southern hemisphere temperate reference floras. At the species level, gender dimorphy was positively associated with fleshy fruit, but at the genus level it was associated with occurrence in New Zealand and a reduced regional distribution. Anemophily was more prevalent in genera occurring on subantarctic islands and the proportion of species with floral traits suggestive of biotic pollination was significantly higher on climatically milder, cool temperate islands. These results support the contention that reliance on biotic pollinators has constrained the distribution of species on SOIs; however, it is also clear that the reproductive biology of few SOI species has been studied in situ and many species likely employ a mixed mating strategy combining biotic pollination with self

  18. 75 FR 4349 - National Estuarine Reserve System

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-27

    ... http://www.grants.gov , unless an applicant does not have Internet access. In that case, hard copies.... The Department of Commerce Pre-Award Notification Requirements for Grants and Cooperative...

  19. Evidence for Bacterial Sulfate Reduction in a Fissured-porous Karst System in Southern Germany

    NASA Astrophysics Data System (ADS)

    Einsiedl, F.; Mayer, B.

    2005-12-01

    Twenty five percent of the world's population uses karst water as drinking water resources. Since karst groundwater systems are highly vulnerable to contamination, groundwater protection and self purification is a major challenge. Up to now research in karst groundwater systems has predominantly concentrated on hydrodynamic processes. Little is known about anoxic processes in oxygen dominated, fracture-matrix diffusion controlled karst aquifers. Isotope measurements comprise a promising tool to identify biogeochemical processes such as bacterial (dissimilatory) sulfate reduction in karstic aquifers. The goal of this study was to determine the sources and the processes affecting sulfate in an oxygen-rich karst aquifer in southern Germany and their dependence on hydrogeological parameters. This was achieved by interpreting tritium data with a simple lumped parameter approach and assessing variations in concentrations and isotopic compositions of sulfate and dissolved inorganic carbon (DIC) with respect to groundwater age. Young groundwater (<30 years) was characterized by comparatively high sulfate concentrations (0.36 mM) and δ34S values similar to those of recent atmospheric deposition (1.5‰). In contrast groundwater with mean residence times >60 years had significantly lower sulfate concentrations (0.08 mM) and markedly higher δ34S values (7.5‰). These results indicate that in karst systems with matrix porosity, bacterial (dissimilatory) sulfate reduction may occur. This process has the potential to contribute to long-term biodegradation of contaminants in the porous rock matrix representing the dominant water reservoir in fissured-porous karst aquifers.

  20. Mapping cattle trade routes in southern Somalia: a method for mobile livestock keeping systems.

    PubMed

    Tempia, S; Braidotti, F; Aden, H H; Abdulle, M H; Costagli, R; Otieno, F T

    2010-12-01

    The Somali economy is the only one in the world in which more than half the population is dependent on nomadic pastoralism. Trade typically involves drovers trekking animals over long distances to markets. A pilot approach for mapping trade routes was undertaken, using the Afmadow to Garissa routes in southern Somalia. The methodology included conducting a workshop with traders to gather preliminary information about the most-used routes and general husbandry practices and training selected drovers to collect data about key features along the routes, using hand-held global positioning system (GPS) devices, radio collar GPS and pictorial data forms. Collected data were then integrated into geographic information systems for analysis. The resultant spatial maps describe the Afmadow to Garissa routes, the speed of livestock movement along these routes and relevant environmental and social features affecting this speed. These data are useful for identifying critical control points for health screening along the routes, which may enable the establishment of a livestock certification system in nomadic pastoral environments.

  1. Colliding winds in five WR+O systems of the Southern hemisphere

    NASA Astrophysics Data System (ADS)

    Fahed, R.; Moffat, A. F. J.

    2012-08-01

    We present the results of an optical spectroscopic follow-up of five WR+O systems of the Southern hemisphere that have not been studied so far for wind-wind collisions: WR 12 (WN8h), WR 21 (WN5o+O7V), WR 30 (WC6+O7.5V), WR 31 (WN4o+O8) and WR 47 (WN6o+O5). Observations were made over an entire contiguous month using the Garrison spectrograph attached to the 0.6-m Helen Sawyer Hogg telescope at Complejo Astronomico El Leoncito. We obtain improved orbital elements for these five systems and provide an estimation of the orbital inclination and shock-cone opening angle for four of them by analysing excess emission profiles with the geometrical model of Lührs. We argue that line variability in one of the stars (WR 12) might be dominated by some dynamic instabilities in the shocked plasma, making the model inappropriate in this case. A sixth star, WR 69 (WC9d+OB), was observed in the programme based on its published photometric period of 2.293 ± 0.005 d. While we found a probable spectroscopic period of 2.15 ± 0.04 d compatible with that of Marchenko et al. (1998), the period is unlikely related to orbital effects, rather to (relatively fast) rotation of the WC9d component of a much longer binary system.

  2. Biostability in distribution systems in one city in southern China: characteristics, modeling and control strategy.

    PubMed

    Lu, Pinpin; Zhang, Xiaojian; Zhang, Chiqian; Niu, Zhangbin; Xie, Shuguang; Chen, Chao

    2014-02-01

    This study investigated the bacterial regrowth in drinking water distribution systems receiving finished water from an advanced drinking water treatment plant in one city in southern China. Thirteen nodes in two water supply zones with different aged pipelines were selected to monitor water temperature, dissolved oxygen (DO), chloramine residual, assimilable organic carbon (AOC), and heterotrophic plate counts (HPC). Regression and principal component analyses indicated that HPC had a strong correlation with chloramine residual. Based on Chick-Watson's Law and the Monod equation, biostability curves under different conditions were developed to achieve the goal of HPC < or = 100 CFU/mL. The biostability curves could interpret the scenario under various AOC concentrations and predict the required chloramine residual concentration under the condition of high AOC level. The simulation was also carried out to predict the scenario with a stricter HPC goal (< or = 50 CFU/mL) and determine the required chloramine residual. The biological regrowth control strategy was assessed using biostability curve analysis. The results indicated that maintaining high chloramine residual concentration was the most practical way to achieve the goal of HPC < or = 100 CFU/mL. Biostability curves could be a very useful tool for biostability control in distribution systems. This work could provide some new insights towards biostability control in real distribution systems.

  3. Review of SISA Student Dissertations on Library and Information Systems and Services in Eastern and Southern Africa.

    ERIC Educational Resources Information Center

    Chowdhury, G. G.; Tadesse, Taye T.

    1995-01-01

    Analyzes student dissertations at the School of Information Studies for Africa (SISA) at Addis Ababa University (Ethiopia) in order to present an overview of the library and information systems and services available in seven eastern and southern African countries: Ethiopia, Kenya, Malawi, Sudan, Tanzania, Uganda, and Zambia. (Author/LRW)

  4. An entropy-based surface velocity method for estuarine discharge measurement

    NASA Astrophysics Data System (ADS)

    Bechle, Adam J.; Wu, Chin H.

    2014-07-01

    An entropy-based method is developed to estimate estuarine river discharge from surface velocity measurements. A two-dimensional velocity profile based on the principle of maximum entropy is employed to express the mean velocity as a function of average surface velocity. The entropy-based flow profile is parameterized by the location of maximum velocity in the channel and the shape of the velocity distribution. The entropy parameters are quantified over the tidal cycle to account for the unsteady nature of estuarine flow. The method was tested using experiments conducted at the Danshui River, the largest estuarine system in Taiwan. Surface velocities were measured using an Automated River-Estuary Discharge Imaging System (AREDIS), and full-channel velocity profiles were measured with a moving-boat ADP survey. Entropy parameters were calibrated over the tidal cycle and linearly correlated with the average surface velocity to facilitate estimation from AREDIS measurements. The discharge calculated from average surface velocity and entropy relationships exhibits a 7.7% relative error compared to the ADP velocity profiles. The error nearly doubles when the mean values for entropy parameters are used instead of the variable parameters, indicating the importance of accounting for the unsteady nature of estuarine flows. Furthermore, the effects of measurement coverage area, types of entropy distribution, and wind-induced drift current on the surface velocity-based discharge measurement are evaluated and discussed. Overall, surface velocity measurements in conjunction with the entropy profiles well represent the flow in a complex estuarine environment to provide a reliable estimate of discharge.

  5. An innovative mobile georadar system for road monitoring and diagnostic: first application in Southern Italy

    NASA Astrophysics Data System (ADS)

    Loperte, Antonio; Soldovieri, Francesco; Bavusi, Massimo; Lapenna, Vincenzo; Piscitelli, Sabatino; Valanzano, Antonio; Pafundi, Donato; Lacorazza, Piero

    2013-04-01

    This work will show the preliminary results obtained through the use of an innovative mobile georadar system for road monitoring and diagnostic. This electromagnetic mobile system is an innovative tool which is able to analyse and monitor the road paving of the overall road network with the aim of individuating critical areas affected by sinking or wearing. The georadar system, equipped by a high frequency antenna (f=1GHz), is mounted on a van and is able to acquire suitable data at velocities up to 70Km/hour. Through the use of this kind of mobile system it is possible to obtain in a short time and with very low costs a wide amount of data on thickness and roughness of the asphalt, superficial sinking and water saturated areas. The first tests were carried out on the main provincial road located in an area of the Southern Apennines affected by hydrogeological risk. This activity has been performed in the framework of a project funded by the Province of Potenza, and realized thank to the consolidated collaboration between the Institute of Methodologies for the Environmental Analysis (IMAA) and the Institute for Electromagnetic Sensing of the Environment (IREA) of the National Research Council of Italy (CNR). This activity has been recognized also at European level as a best practice procedure in the frame of "Window on GMES - Global Monitoring for Environment and Security". The application of this innovative electromagnetic system on the overall road system of the province of Potenza will enable the decision-makers to plan with more detail and awareness the technical actions addressed to maintain and repair the road sections really affected by anomalies, with a time-saving and lower management costs.

  6. Determination of thrust compression systems with a multisource geoscientific data processing in the southern margin of Ordos basin, China

    SciTech Connect

    Yongjie, T.; Genderen, J.L. van

    1996-08-01

    In this paper, the multisource geoscientific data, such as TM data, NOAA data, the data of Bouguer gravity anomaly and aeromagnetic anomaly, the multisource geophysical processing methods, such as upward continuations, vertical derivative and gradient image, and synthetic image processing method - remote sensing image processing and geophysical image processing under I{sup 2}S600, are used to study the reverse faults or thrusts in the southern margin of Ordos basin, China. On the basis of these results and with geological investigation in the field, the authors have determined three thrust compression systems, named EW thrust compression system, NE thrust compression system and NW thrust compression system. These three systems reveal the regularity of geological structural evolution in the southern margin of Ordos basis and in the north side of Qinling Orogenic Belt.

  7. Sources of organic matter for flatfish juveniles in coastal and estuarine nursery grounds: A meta-analysis for the common sole (Solea solea) in contrasted systems of Western Europe

    NASA Astrophysics Data System (ADS)

    Le Pape, O.; Modéran, J.; Beaunée, G.; Riera, P.; Nicolas, D.; Savoye, N.; Harmelin-Vivien, M.; Darnaude, A. M.; Brind'Amour, A.; Le Bris, H.; Cabral, H.; Vinagre, C.; Pasquaud, S.; França, S.; Kostecki, C.

    2013-01-01

    Coastal and estuarine nursery grounds are essential habitats for sustaining flatfish stocks since only these shallow and productive areas provide the high food supply that allows maximizing juvenile growth and survival in most flatfish species. However, the main organic matter sources at the basis of benthic food webs might differ drastically between estuarine nursery grounds under strong freshwater influences, where food webs are mainly supported by continental organic matter, and coastal ecosystems under limited freshwater influence, where the local marine primary production is the main source of carbon for the benthos. To better understand the links between continental inputs to the coastal zone and stock maintenance in the highly prized common sole, Solea solea (L.), we investigated the variability in the organic matter sources supporting the growth of its young-of-the-year (YoY) in five contrasted estuarine and coastal nursery grounds under varying freshwater influence. Stable isotopes of carbon and nitrogen allowed tracing the origin of the organic matter exploited by YoY soles in the very first months following their benthic settlement, i.e. when most of the juvenile mortality occurs in the species. A mixing model was run to unravel and quantify the contribution of all major potential sources of organic matter to sole food webs, with a sensitivity analysis allowing assessment of the impact of various trophic enrichment factors on model outputs. This meta-analysis demonstrated a relative robustness of the estimation of the respective contributions of the various organic matter sources. At the nursery scale, the upstream increase in freshwater organic matter exploitation by YoY soles and its positive correlation with inter-annual variations in the river flow confirmed previous conclusions about the importance of organic matter from continental origin for juvenile production. However, inter-site differences in the organic matter sources exploited for growth

  8. Scales and properties of cold filaments in the southern Benguela upwelling system

    NASA Astrophysics Data System (ADS)

    Hösen, Elisabeth; Möller, Judith; Jochumsen, Kerstin; Quadfasel, Detlef

    2015-04-01

    The Benguela upwelling system is one of the four most active upwelling systems in the world. Meso-scale and submeso-scale structures like eddies and filaments are build up, due to instabilities at the front between the cold upwelled water and the warm surface water offshore. The heat exchange across the front is carried out mainly by such structures, especially filaments due to their offshore extent. Therefore cold upwelling filaments play an important role in the heat budget of the south-east Atlantic. This study is focussed on the southern part of the Benguela upwelling system, especially on the upwelling cell off Lüderitz. We combine satellite data and ship-borne measurements to investigate the appearance of such filaments and their properties (vertical and horizontal extent, mean temperature anomaly, mean velocity etc.). We use infra-red measurements of the MODIS satellite from 2011 to 2014. Two cruises in the region of interest were carried out in August 2013 and February 2014 and provide highly resolved surface data of temperature and salinity as well as vertical information on temperature, salinity and velocity. The spatial and temporal distribution of the filaments including the meridional and longitudinal extent is determined using a frequency analysis (wavelet analysis) of our data sets. Most filaments occurred between 25°S and 27°S, corresponding to the position of the Lüderitz cell. The observed filaments have a meridional extent between 5km and 44km and propagate more than 20km offshore. The lifetime of a filament is between 2 and 12 days. The time series of satellite data provides information on the seasonal and year-to-year variability in the appearance of filaments. Additionally the variability of the forcing winds is analysed and results are connected to the appearance of filaments. The filament activity is highest in southern summer, corresponding to the main upwelling season. The ship-borne measurements allow a highly resolved analysis of the

  9. Modelling the effect of hydrological change on estuarine health: An Australian Perspective. (Invited)

    NASA Astrophysics Data System (ADS)

    Bruce, L. C.; Adiyanti, S.; Ruibal, A. L.; Hipsey, M. R.

    2013-12-01

    Estuaries provide an important role in the filtering and transformation of carbon and nutrients from coastal catchments into the marine environment. Global trends including climate change, increased population, industrialization and agriculture have led to the rapid deterioration of estuarine ecosystems across the world. Within the Australian context, a particular concern is how changes to hydrological regimes, due to both water diversions and climate variability, are contributing to increased stress and consequent decline in estuarine health. In this study we report the modeling output of five Australian estuaries, each with different hydrological regimes and alternative management issues relating to altered hydrology: 1) The Yarra River estuary is a highly urbanized system, also receiving agriculturally derived nutrients, where the concern is the role of periodic hypoxia in reducing the assimilation capacity of nitrogen and thus increased risk of algal blooms forming in the coastal environment; 2) The upper Swan River estuary in Western Australia, which experiences persistent anoxia and hypoxia brought about by reduced flows has led to the commissioning of several oxygenation plants to alleviate stress on biodiversity and overall estuarine health; 3) The health of the Caboolture estuary in Queensland has deteriorated in the past decade with the aim of model development to quantify the various sources of surface and groundwater derived nutrients; 4) The construction of an additional channel to increase flushing in the Peel Harvey estuary in Western Australia was designed to control persistent harmful algal blooms; and 5) The Lower River Murray estuary experienced a prolonged drought that led to the development of acid sulfate soils and acid drainage deteriorating water quality. For these applications we applied 3-D hydrodynamic-biogeochemical models to determine underlying relationships between altered flow regimes, increased temperatures and the response of

  10. Economic performance of small ruminants in mixed-farming systems of Southern Ethiopia.

    PubMed

    Legesse, Getahun; Siegmund-Schultze, Marianna; Abebe, Girma; Zárate, Anne Valle

    2010-10-01

    This study evaluates the household income contribution and the profitability of traditional small ruminant enterprises in two mixed-farming systems of southern Ethiopia (viz. Adilo and Kofele). Small ruminant production is an integral part of mixed systems in the Ethiopian highlands. The assessment of the current economic performance of small ruminants indicates production-related opportunities and constraints and provides baseline data against which the success of future interventions can be measured. Detailed information on economic parameters was gathered through a 1-year period of flock and household monitoring (155 households) between September 2005 and August 2006. Structured surveys were conducted with the participating households to elicit information on income-expense details of small ruminant and other agricultural enterprises. Small ruminants contributed considerably to cash income and to a limited extent to human nutrition especially when other sources were in short supply. The annual profit per animal ranged from 20 to 37 Ethiopian Birr. The return to capital was 17% in Kofele and 29% in Adilo, with both values vastly exceeding the national interest rate. The sale of small ruminants contributed to 39% and 23% of total farm cash income among small ruminant keepers in Adilo and Kofele, respectively. Sale prices are highest before holidays. Researches should target at how to use available feed resources in a timely and cost-effective fashion to make use of the seasonal market opportunities.

  11. Traditional goat husbandry practice under pastoral systems in South Omo zone, southern Ethiopia.

    PubMed

    Tesfahun, Biruh; Kebede, Kefelegn; Effa, Kefena

    2017-03-01

    This study was carried out to describe goat production system under pastoralists' management in three districts of South Omo zone, southern Ethiopia. The districts were Benatsemay, Hamer, and Dasenech. Questionnaires were developed and used to collect data regarding pastoralists' management practices and production system of goats. A total of 180 households were interviewed to capture relevant information. Data collected through questionnaires were subjected to statistical analysis to generate descriptive statistics. Ranking was explained by calculating indexes. The primary purpose of raising goats was for social prestige in Benatsemay and Hamer but for milk production in Dasenech. Body size was the primary preference in Benatsemay and Hamer while milk yield was preferred most in Dasenech. Rangeland grazing was the major feed source in the study area in both dry and wet seasons. Pond and river were the common sources of water reported by farmers in the study districts but inadequate and poor quality. Disease prevalence was the top major constraint in goat husbandry in the three districts.

  12. Hydrological and ecological impacts of dams on the Kafue Flats floodplain system, southern Zambia

    NASA Astrophysics Data System (ADS)

    Mumba, M.; Thompson, J. R.

    Developmental changes in river basins in Africa have become a reality. Many wetland ecosystems have been impacted by dams and other hydrological interventions resulting in both foreseen and unexpected consequences. The Kafue Flats in southern Zambia is an extensive floodplain system that lies within the middle Kafue river basin. The floodplain is about 255 km long and 60 km wide, covering an area of approximately 6,500 km 2. It is currently sandwiched between two large dams which are approximately 270 km apart. These dams have completely altered the hydrological regime of the system. Backwater from the downstream dam and releases from upstream have created a permanently flooded area within the floodplain that was not present in the past. Elsewhere, flooding has been reduced. The ecological consequences of these changes for the floodplain, which hosts two national parks (both Ramsar sites), have been extensive. Hydrological and vegetation changes have impacted the habitat for important wildlife communities including the endemic antelope, Kobus leche kafuensis. The most dramatic change in vegetation is associated with the colonisation of parts of the floodplain by the invasive alien plant, Mimosa pigra. This paper discusses these changes and their potential consequences.

  13. Enhancing the routine health information system in rural southern Tanzania: successes, challenges and lessons learned.

    PubMed

    Maokola, W; Willey, B A; Shirima, K; Chemba, M; Armstrong Schellenberg, J R M; Mshinda, H; Alonso, P; Tanner, M; Schellenberg, D

    2011-06-01

    To describe and evaluate the use of handheld computers for the management of Health Management Information System data. Electronic data capture took place in 11 sentinel health centres in rural southern Tanzania. Information from children attending the outpatient department (OPD) and the Expanded Program on Immunization vaccination clinic was captured by trained local school-leavers, supported by monthly supervision visits. Clinical data included malaria blood slides and haemoglobin colour scale results. Quality of captured data was assessed using double data entry. Malaria blood slide results from health centre laboratories were compared to those from the study's quality control laboratory. The system took 5 months to implement, and few staffings or logistical problems were encountered. Over the following 12 months (April 2006-March 2007), 7056 attendances were recorded in 9880 infants aged 2-11 months, 50% with clinical malaria. Monthly supervision visits highlighted incomplete recording of information between OPD and laboratory records, where on average 40% of laboratory visits were missing the record of their corresponding OPD visit. Quality of microscopy from health facility laboratories was lower overall than that from the quality assurance laboratory. Electronic capture of HMIS data was rapidly and successfully implemented in this resource-poor setting. Electronic capture alone did not resolve issues of data completeness, accuracy and reliability, which are essential for management, monitoring and evaluation; suggestions to monitor and improve data quality are made. © 2011 Blackwell Publishing Ltd.

  14. Southern Very Low Mass Stars and Brown Dwarfs in Wide Binary and Multiple Systems

    NASA Astrophysics Data System (ADS)

    Caballero, José Antonio

    2007-09-01

    The results of the Königstuhl survey in the Southern Hemisphere are presented. I have searched for common proper motion companions to 173 field very low mass stars and brown dwarfs with spectral types >M5.0 V and magnitudes J<~14.5 mag. I have measured for the first time the common proper motion of two new wide systems containing very low mass components, Königstuhl 2 AB and 3 A-BC. Together with Königstuhl 1 AB and 2M 0126-50 AB, they are among the widest systems in their respective classes (r=450-11,900 AU). I have determined the minimum frequency of field wide multiples (r>100 AU) with late-type components at 5.0%+/-1.8% and the frequency of field wide late-type binaries with mass ratios q>0.5 at 1.2%+/-0.9%. These values represent a key diagnostic of evolution history and low-mass star and brown dwarf formation scenarios. In addition, the proper motions of 62 field very low mass dwarfs are measured here for the first time.

  15. Hydrochemical zonation of the western part of Göksu Delta aquifer system, Southern Turkey

    NASA Astrophysics Data System (ADS)

    Dokuz, U. E.; Çelik, M.; Arslan, Ş.; Engin, H.

    2012-04-01

    In general, coastal areas are preferred places for human settlement, especially at places where infrastructure routes benefit from rivers, streets, or harbours. As a result, these areas usually suffer from rising population and endure increasingly high demand on natural resources like water. Göksu Delta, located in southern Turkey, is one of the important wetland areas of Turkey at the Mediterranean coast. It is divided into two parts by Göksu River. The western part of the delta, which is the subject matter of this study, hosts fertile agricultural fields, touristic places and a Special Environmental Protection Area. These properties of the region lead to a water-dependent ecosystem where groundwater has widely been used for agricultural and domestic purposes. When the exploitation of groundwater peaked in the middle of 1990s, the groundwater levels dropped and seawater intruded. General Directorate of State Hydraulic Works tried to stop seawater intrusion by building irrigation channels connected to Göksu River and banned drilling of new wells for groundwater exploitation, although it is hard to control the drilling of wells without official permit. Geological studies show that the delta is composed of terrestrial sediments including clay to coarse sand deposited during Quaternary. The heterogeneous sediments of Göksu Delta cause hydrogeological features of the aquifer systems to be heterogeneous and anisotropic. Hydrogeological investigations, therefore, indicate mainly two different aquifers, shallow and deep, separated by an aquitard. The shallow aquifer is under unconfined to confined conditions from north to south while the deep aquifer is under confined conditions. This study focuses on hydrogeochemical zonation in terms of hydrochemical processes that affect the Göksu Delta aquifer systems. For this purpose, hydrogeochemical and isotopic studies are conducted to understand the salinisation and softening processes of groundwater. The physicochemical

  16. LANDSCAPE CORRELATES TO ESTUARINE CONDITION

    EPA Science Inventory

    Estuaries are important transition zones between land and sea, yet little is known about how landscapes influence these systems. Using broad scale Environmental Monitoring and Assessment Program (EMAP) data collected in small estuaries of the Virginian Biogeographic Province, w...

  17. LANDSCAPE CORRELATES TO ESTUARINE CONDITION

    EPA Science Inventory

    Estuaries are important transition zones between land and sea, yet little is known about how landscapes influence these systems. Using broad scale Environmental Monitoring and Assessment Program (EMAP) data collected in small estuaries of the Virginian Biogeographic Province, w...

  18. Ecoengineering with Ecohydrology: Successes and failures in estuarine restoration

    NASA Astrophysics Data System (ADS)

    Elliott, Michael; Mander, Lucas; Mazik, Krysia; Simenstad, Charles; Valesini, Fiona; Whitfield, Alan; Wolanski, Eric

    2016-07-01

    Ecological Engineering (or Ecoengineering) is increasingly used in estuaries to re-create and restore ecosystems degraded by human activities, including reduced water flow or land poldered for agricultural use. Here we focus on ecosystem recolonization by the biota and their functioning and we separate Type A Ecoengineering where the physico-chemical structure is modified on the basis that ecological structure and functioning will then follow, and Type B Ecoengineering where the biota are engineered directly such as through restocking or replanting. Modifying the physical system to create and restore natural processes and habitats relies on successfully applying Ecohydrology, where suitable physical conditions, especially hydrography and sedimentology, are created to recover estuarine ecology by natural or human-mediated colonisation of primary producers and consumers, or habitat creation. This successional process then allows wading birds and fish to reoccupy the rehabilitated areas, thus restoring the natural food web and recreating nursery areas for aquatic biota. We describe Ecohydrology principles applied during Ecoengineering restoration projects in Europe, Australia, Asia, South Africa and North America. These show some successful and sustainable approaches but also others that were less than successful and not sustainable despite the best of intentions (and which may even have harmed the ecology). Some schemes may be 'good for the ecologists', as conservationists consider it successful that at least some habitat was created, albeit in the short-term, but arguably did little for the overall ecology of the area in space or time. We indicate the trade-offs between the short- and long-term value of restored and created ecosystems, the success at developing natural structure and functioning in disturbed estuaries, the role of this in estuarine and wetland management, and the costs and benefits of Ecoengineering to the socio-ecological system. These global case

  19. An assessment of landscape characteristics affecting estuarine nitrogen loading in an urban watershed.

    PubMed

    Yang, Xiaojun

    2012-02-01

    Exploring the quantitative association between landscape characteristics and the ecological conditions of receiving waters has recently become an emerging area for eco-environmental research. While the landscape-water relationship research has largely targeted on inland aquatic systems, there has been an increasing need to develop methods and techniques that can better work with coastal and estuarine ecosystems. In this paper, we present a geospatial approach to examine the quantitative relationship between landscape characteristics and estuarine nitrogen loading in an urban watershed. The case study site is in the Pensacola estuarine drainage area, home of the city of Pensacola, Florida, USA, where vigorous urban sprawling has prompted growing concerns on the estuarine ecological health. Central to this research is a remote sensor image that has been used to extract land use/cover information and derive landscape metrics. Several significant landscape metrics are selected and spatially linked with the nitrogen loading data for the Pensacola bay area. Landscape metrics and nitrogen loading are summarized by equal overland flow-length rings, and their association is examined by using multivariate statistical analysis. And a stepwise model-building protocol is used for regression designs to help identify significant variables that can explain much of the variance in the nitrogen loading dataset. It is found that using landscape composition or spatial configuration alone can explain most of the nitrogen loading variability. Of all the regression models using metrics derived from a single land use/cover class as the independent variables, the one from the low density urban gives the highest adjusted R-square score, suggesting the impact of the watershed-wide urban sprawl upon this sensitive estuarine ecosystem. Measures towards the reduction of non-point source pollution from urban development are necessary in the area to protect the Pensacola bay ecosystem and its

  20. Benthic and pelagic pathways of methylmercury bioaccumulation in estuarine food webs of the northeast United States.

    PubMed

    Chen, Celia Y; Borsuk, Mark E; Bugge, Deenie M; Hollweg, Terill; Balcom, Prentiss H; Ward, Darren M; Williams, Jason; Mason, Robert P

    2014-01-01

    Methylmercury (MeHg) is a contaminant of global concern that bioaccumulates and bioamagnifies in marine food webs. Lower trophic level fauna are important conduits of MeHg from sediment and water to estuarine and coastal fish harvested for human consumption. However, the sources and pathways of MeHg to these coastal fisheries are poorly known particularly the potential for transfer of MeHg from the sediment to biotic compartments. Across a broad gradient of human land impacts, we analyzed MeHg concentrations in food webs at ten estuarine sites in the Northeast US (from the Hackensack Meadowlands, NJ to the Gulf of Maine). MeHg concentrations in water column particulate material, but not in sediments, were predictive of MeHg concentrations in fish (killifish and Atlantic silversides). Moreover, MeHg concentrations were higher in pelagic fauna than in benthic-feeding fauna suggesting that MeHg delivery to the water column from methylation sites from within or outside of the estuary may be an important driver of MeHg bioaccumulation in estuarine pelagic food webs. In contrast, bulk sediment MeHg concentrations were only predictive of concentrations of MeHg in the infaunal worms. Our results across a broad gradient of sites demonstrate that the pathways of MeHg to lower trophic level estuarine organisms are distinctly different between benthic deposit feeders and forage fish. Thus, even in systems with contaminated sediments, transfer of MeHg into estuarine food webs maybe driven more by the efficiency of processes that determine MeHg input and bioavailability in the water column.

  1. Benthic and Pelagic Pathways of Methylmercury Bioaccumulation in Estuarine Food Webs of the Northeast United States

    PubMed Central

    Chen, Celia Y.; Borsuk, Mark E.; Bugge, Deenie M.; Hollweg, Terill; Balcom, Prentiss H.; Ward, Darren M.; Williams, Jason; Mason, Robert P.

    2014-01-01

    Methylmercury (MeHg) is a contaminant of global concern that bioaccumulates and bioamagnifies in marine food webs. Lower trophic level fauna are important conduits of MeHg from sediment and water to estuarine and coastal fish harvested for human consumption. However, the sources and pathways of MeHg to these coastal fisheries are poorly known particularly the potential for transfer of MeHg from the sediment to biotic compartments. Across a broad gradient of human land impacts, we analyzed MeHg concentrations in food webs at ten estuarine sites in the Northeast US (from the Hackensack Meadowlands, NJ to the Gulf of Maine). MeHg concentrations in water column particulate material, but not in sediments, were predictive of MeHg concentrations in fish (killifish and Atlantic silversides). Moreover, MeHg concentrations were higher in pelagic fauna than in benthic-feeding fauna suggesting that MeHg delivery to the water column from methylation sites from within or outside of the estuary may be an important driver of MeHg bioaccumulation in estuarine pelagic food webs. In contrast, bulk sediment MeHg concentrations were only predictive of concentrations of MeHg in the infaunal worms. Our results across a broad gradient of sites demonstrate that the pathways of MeHg to lower trophic level estuarine organisms are distinctly different between benthic deposit feeders and forage fish. Thus, even in systems with contaminated sediments, transfer of MeHg into estuarine food webs maybe driven more by the efficiency of processes that determine MeHg input and bioavailability in the water column. PMID:24558491

  2. Shock, Stress or Signal? Implications of Freshwater Flows for a Top-Level Estuarine Predator

    PubMed Central

    Taylor, Matthew D.; van der Meulen, Dylan E.; Ives, Matthew C.; Walsh, Chris T.; Reinfelds, Ivars V.; Gray, Charles A.

    2014-01-01

    Physicochemical variability in estuarine systems plays an important role in estuarine processes and in the lifecycles of estuarine organisms. In particular, seasonality of freshwater inflow to estuaries may be important in various aspects of fish lifecycles. This study aimed to further understand these relationships by studying the movements of a top-level estuarine predator in response to physicochemical variability in a large, temperate south-east Australian estuary (Shoalhaven River). Mulloway (Argyrosomus japonicus, 47–89 cm total length) were surgically implanted with acoustic transmitters, and their movements and migrations monitored over two years via fixed-position VR2W acoustic receivers configured in a linear array along the length of the estuary. The study period included a high degree of abiotic variability, with multiple pulses (exponentially high flows over a short period of time) in fresh water to the estuary, as well as broader seasonal variation in flow, temperature and conductivity. The relative deviation of fish from their modal location in the estuary was affected primarily by changes in conductivity, and smaller fish (n = 4) tended to deviate much further downstream from their modal position in the estuary than larger fish (n = 8). High-flow events which coincided with warmer temperatures tended to drive mature fish down the estuary and potentially provided a spawning signal to stimulate aggregation of adults near the estuary mouth; however, this relationship requires further investigation. These findings indicate that pulse and press effects of freshwater inflow and associated physicochemical variability play a role in the movements of mulloway, and that seasonality of large freshwater flows may be important in spawning. The possible implications of river regulation and the extraction of freshwater for consumptive uses on estuarine fishes are discussed. PMID:24752585

  3. Major factors influencing the elemental composition of surface estuarine sediments: the case of 15 estuaries in Portugal.

    PubMed

    Mil-Homens, M; Vale, C; Raimundo, J; Pereira, P; Brito, P; Caetano, M

    2014-07-15

    Upper sediments (0-5 cm) were sampled in 94 sites of water bodies of the fifteen Portuguese estuaries characterized by distinct settings of climate, topography and lithology, and marked by diverse anthropogenic pressures. Confined areas recognized as highly anthropogenic impacted, as well as areas dominated by erosion or frequently dredged were not sampled. Grain size, organic carbon (Corg), Al and trace elements (As, Cd, Co, Cr, Cu, Hg, Ni, Pb and Zn) were determined. Normalisation of trace element concentrations to Al and Corg, correlations between elements and Principal Component Analysis (PCA) allowed identifying elemental associations and the relevance of grain-size, lithology and anthropogenic inputs on sediment chemical composition. Whereas grain-size is the dominant effect for the majority of the studied estuaries, the southern estuaries Mira, Arade and Guadiana are dominated by specific lithologies of their river basins, and anthropogenic effects are identified in Ave, Leça, Tagus and Sado. This study emphasizes how baseline values of trace elements in sediments may vary within and among estuarine systems. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Elevated naturally occurring arsenic in a semiarid oxidizing system, Southern High Plains aquifer, Texas, USA

    USGS Publications Warehouse

    Scanlon, B.R.; Nicot, J.-P.; Reedy, R.C.; Kurtzman, D.; Mukherjee, A.; Nordstrom, D.K.

    2009-01-01

    High groundwater As concentrations in oxidizing systems are generally associated with As adsorption onto hydrous metal (Al, Fe or Mn) oxides and mobilization with increased pH. The objective of this study was to evaluate the distribution, sources and mobilization mechanisms of As in the Southern High Plains (SHP) aquifer, Texas, relative to those in other semiarid, oxidizing systems. Elevated groundwater As levels are widespread in the southern part of the SHP (SHP-S) aquifer, with 47% of wells exceeding the current EPA maximum contaminant level (MCL) of 10 μg/L (range 0.3–164 μg/L), whereas As levels are much lower in the north (SHP-N: 9% ⩾ As MCL of 10 μg/L; range 0.2–43 μg/L). The sharp contrast in As levels between the north and south coincides with a change in total dissolved solids (TDS) from 395 mg/L (median north) to 885 mg/L (median south). Arsenic is present as arsenate (As V) in this oxidizing system and is correlated with groundwater TDS (Spearman’s ρ = 0.57). The most likely current source of As is sorbed As onto hydrous metal oxides based on correlations between As and other oxyanion-forming elements (V, ρ = 0.88; Se, ρ = 0.54; B, ρ = 0.51 and Mo, ρ = 0.46). This source is similar to that in other oxidizing systems and constitutes a secondary source; the most likely primary source being volcanic ashes in the SHP aquifer or original source rocks in the Rockies, based on co-occurrence of As and F (ρ = 0.56), oxyanion-forming elements and SiO2 (ρ = 0.41), which are found in volcanic ashes. High groundwater As concentrations in some semiarid oxidizing systems are related to high evaporation. Although correlation of As with TDS in the SHP aquifer may suggest evaporative concentration, unenriched stable isotopes (δ2H: −65 to −27; δ18O: −9.1 to −4.2) in the SHP aquifer do not support evaporation. High TDS in the SHP aquifer is most likely related to upward movement of saline water from the underlying

  5. Drivers of estuarine benthic species distribution patterns following a restoration of a seagrass bed: a functional trait analyses.

    PubMed

    Dolbeth, Marina; Cardoso, Patrícia; Grilo, Tiago; Raffaelli, Dave; Pardal, Miguel Ângelo

    2013-07-15

    We integrate information on functional diversity (FD) patterns from estuarine intertidal benthic communities from different habitats and along a temporal disturbance gradient, to understand the drivers of species coexistence patterns. Species and traits' biomass levels seemed to be first determined by habitat filtering, selecting those traits better adapted to the biologically challenging estuarine environment. Within that subset of traits and within each habitat, biotic interactions were probably high, as evidenced by high α-diversity and community weighted mean differences. The former patterns hold for the disturbance/recovery scenario considered. However, as the estuary recovered, biomass became more distributed among different trait categories, consistent with increases in FD when the seagrass started to increase. Policy towards the restoration of seagrass bed and other biogenic structures, and improving the connectivity within adjacent systems were confirmed and suggested, as this would imply higher FD and potentially higher resilience to disturbance within the estuarine intertidal system.

  6. Estuarine consumers utilize marine, estuarine and terrestrial organic matter and provide connectivity among these food webs

    EPA Science Inventory

    The flux of organic matter (OM) across ecosystem boundaries can influence estuarine food web dynamics and productivity. However, this process is seldom investigated taking into account all the adjacent ecosystems (e.g. ocean, river, land) and different hydrological settings (i.e....

  7. Estuarine consumers utilize marine, estuarine and terrestrial organic matter and provide connectivity among these food webs

    EPA Science Inventory

    The flux of organic matter (OM) across ecosystem boundaries can influence estuarine food web dynamics and productivity. However, this process is seldom investigated taking into account all the adjacent ecosystems (e.g. ocean, river, land) and different hydrological settings (i.e....

  8. Coastal and Estuarine Waters: Light Behavior. Coastal and Estuarine Waters: Optical Sensors and Remote Sensing.

    EPA Science Inventory

    This article summarizes the use of remote sensing techniques and technology to monitor coastal and estuarine waters. These waters are rich in mineral particles stirred up from the seabed by tides and waves and dissolved organic matter transported by rivers. The majority of the li...

  9. Coastal and Estuarine Waters: Light Behavior. Coastal and Estuarine Waters: Optical Sensors and Remote Sensing.

    EPA Science Inventory

    This article summarizes the use of remote sensing techniques and technology to monitor coastal and estuarine waters. These waters are rich in mineral particles stirred up from the seabed by tides and waves and dissolved organic matter transported by rivers. The majority of the li...

  10. Seismic anisotropy of the lithosphere-asthenosphere system beneath southern Madagascar

    NASA Astrophysics Data System (ADS)

    Reiss, Miriam Christina; Rümpker, Georg; Tilmann, Frederik; Yuan, Xiaohui; Josiane Rindraharisaona, Elisa

    2015-04-01

    Madagascar is considered as a key region with respect to the assembly and break-up of the supercontinent Gondwana. Following the collision between East- and West-Gondwana (~700-650 Ma), its position was central to the Panafrican orogenesis. Madagascar then separated from East Africa and later from the Indian and Antarctic plates until these processes came to a halt about 69 Ma ago. Today, Madagascar consists of different tectonic units; the eastern parts (two thirds of the island) are composed mainly of Precambian rocks, whereas the western part is dominated by sedimentary deposits. Furthermore, southern Madagascar is characterized by several NS to NW-SE trending shear zones. Madagascar has been the target of a number of geological studies, but seismological investigations of the presumed complex lithosphere-asthenosphere system and of deeper upper-mantle structures are sparse. To increase our understanding of these structures and related tectonic processes, we installed a dense temporary seismic network in southern Madagascar. It consisted of 25 broadband and 25 short-period stations, which were in operation for up to 2 years between 2012 and 2014. The broadband stations crossed the island along an east-west profile; the eastern section was supplemented by a network of short-period stations. Here we present results from shear-wave splitting analyses to infer the seismic anisotropy of the lithosphere-asthenosphere system in response to deformational processes. The polarization of the fast shear wave and the delay time between the fast and slow waves provide constraints on the anisotropic fabric. For our study, we use SKS-phases from up to 12 events recorded at the temporary stations and from 10 events at the permanent GEOFON station VOI. We first apply a single-event splitting analysis by minimizing the transverse component. For stations that do not show a significant azimuthal dependence of the splitting parameters, we also apply a joint inversion involving all

  11. Proceedings of the 30th Southern Conservation Agricultural Systems Conference and the 8th Annual Georgia Conservation Production Systems Training Conference, Tifton, Georgia, July 29-31, 2008

    USDA-ARS?s Scientific Manuscript database

    This 2008 conference to be held at the University of Georgia Tifton Campus Conference Center in Tifton, GA, on 29-31 July 2008, will be a joint effort of the 30th Southern Conservation Agricultural Systems Conference (SCASC) and the 8th Annual Conservation Production Systems Training Conference (CPS...

  12. Nitrous oxide emissions from wetland rice-duck cultivation systems in Southern China.

    PubMed

    Li, Chengfang; Cao, Cougui; Wang, Jingping; Zhan, Ming; Yuan, Weiling; Ahmad, Shahrear

    2009-01-01

    Nitrous oxide (N2O) emissions from a rice-duck cultivation system in the subtropical region of China and its regulating factors were investigated by using a static chambers technique during rice growth seasons in 2006 and 2007. The experimental field was equally divided into six plots for two different treatments: One was a conventional rice field (CK) and the other was a rice-duck ecosystem (RD). With the same amount of urea applied as basal fertilization, N2O emission fluxes from RD and CK followed a similar seasonal variation trend. During the flooding seasons, the N2O emission flux was not correlated with temperature, but it was significantly related to soil inorganic nitrogen (SIN) (p < 0.01) and soil pH (p < 0.01). After drainage, the N2O emission flux was not correlated with temperature, SIN, and soil pH. Our experimental data showed that peaks of N2O emission flux occurred both in 2 weeks after urea application and after drainage. Compared to CK, RD could significantly increase N2O emission. We evaluated the integrated global warming potentials (GWPs) of a rice-duck cultivation system based on methane (CH4) and N2O emission, which showed that RD could suppress the total amount of CH4 and N2O emissions from rice paddies. Moreover, because the decrease of CH4 emissions from RD compared to CK was far more than the increase of N2O emissions from RD compared to CK, RD greatly reduced integrated GWPs (CH4 + N2O) compared to CK. So, the rice-duck cultivation system is an effective strategy for reducing integrated GWPs of the rice-duck cultivation systems based on CH4 and N2O in southern China and will contribute to alleviating global warming.

  13. Conceptual PHES-system models of the Aysén watershed and fjord (Southern Chile): testing a brainstorming strategy.

    PubMed

    Marín, Víctor H; Delgado, Luisa E; Bachmann, Pamela

    2008-09-01

    The use of brainstorming techniques for the generation of conceptual models, as the basis for the integrated management of physical-ecological-social systems (PHES-systems) is tested and discussed. The methodology is applied in the analysis of the Aysén fjord and watershed (Southern Chilean Coast). Results show that the proposed methods can be adequately used in management scenarios characterized by highly hierarchical, experts/non-experts membership.

  14. Modeling centuries of estuarine morphodynamics in the Western Scheldt estuary

    NASA Astrophysics Data System (ADS)

    Dam, G.; Wegen, M.; Labeur, R. J.; Roelvink, D.

    2016-04-01

    We hindcast a 110 year period (1860-1970) of morphodynamic behavior of the Western Scheldt estuary by means of a 2-D, high-resolution, process-based model and compare results to a historically unique bathymetric data set. Initially, the model skill decreases for a few decades. Against common perception, the model skill increases after that to become excellent after 110 years. We attribute this to the self-organization of the morphological system which is reproduced correctly by the numerical model. On time scales exceeding decades, the interaction between the major tidal forcing and the confinement of the estuary overrules other uncertainties. Both measured and modeled bathymetries reflect a trend of decreasing energy dissipation, less morphodynamic activity, and thus a more stable morphology over time, albeit that the estuarine adaptation time is long (approximately centuries). Process-based models applied in confined environments and under constant forcing conditions may perform well especially on long (greater than decades) time scales.

  15. Dispersal, Genetic Differentiation and Speciation in Estuarine Organisms

    NASA Astrophysics Data System (ADS)

    Bilton, D. T.; Paula, J.; Bishop, J. D. D.

    2002-12-01

    For some of their occupants, estuaries represent spatially discrete habitats, isolated from each other by barriers to dispersal or physiological tolerance. We present contrasting strategies for the retention or export of larvae from their estuary of origin, and consider the implications these have on population structure and divergence. Reported patterns of genetic differentiation and inferred gene flow in estuarine taxa (principally animals) are reviewed, and difficulties in the interpretation of existing genetic data discussed. Species concepts and models of speciation relevant to estuaries are outlined, and patterns of speciation of estuarine taxa reviewed. It is concluded that estuarine environments tend to restrict gene flow and impose distinct selective regimes, generating physiologically adapted populations divergent from their marine counterparts, and the potential for in situ speciation in complete or partial isolation. The resulting taxa may represent sibling or cryptic species groups of truly estuarine origin, rather than simply estuarine populations of marine eurytopes.

  16. Applications of remote sensing to estuarine management

    NASA Technical Reports Server (NTRS)

    Munday, J. C., Jr.; Gordon, H. H.; Hennigar, H. F.

    1977-01-01

    Remote sensing was used in the resolution of estuarine problems facing federal and Virginia governmental agencies. A prototype Elizabeth River Surface Circulation Atlas was produced from photogrammetry to aid in oil spill cleanup and source identification. Aerial photo analysis twice led to selection of alternative plans for dredging and spoil disposal which minimized marsh damage. Marsh loss due to a mud wave from a highway dyke was measured on sequential aerial photographs. An historical aerial photographic sequence gave basis to a potential Commonwealth of Virginia legal claim to accreting and migrating coastal islands.

  17. Contamination by Arsenate in Oxidizing Groundwater, Southern Gulf Coast Aquifer System, Texas

    NASA Astrophysics Data System (ADS)

    Gates, J. B.; Nicot, J.; Reedy, R. C.; Scanlon, B. R.

    2009-12-01

    Groundwater arsenic concentrations exceed the U.S. EPA maximum contaminant level for drinking water (10 μg/L) in about one-third of wells in the southern Gulf Coast Aquifer System (GCAS) in Texas, representing a potential public health hazard and an environmental compliance challenge to numerous small public water supply systems. The aim of this study is to better understand the hydrogeochemical mechanisms underpinning the widespread distribution of elevated groundwater arsenic concentrations in the region. Here we focus upon arsenic contamination in unconfined portions of the aquifer system. The investigation is based upon chemical analyses of a field transect of 27 groundwater samples collected from across three units of the GCAS; stratified water quality sampling from one additional well; and relevant water chemistry data from the Texas Water Development Board groundwater database (more than 500 samples). Chemical results from the field study showed that carbonate weathering and active recharge in the unconfined zone result in circum-neutral pH and oxidizing redox conditions, which are typically amenable to arsenic immobilization by adsorption of As(V) onto mineral oxides and clays. However, arsenic concentrations were found up to 129 μg/L (median 12 μg/L), and As(V) represented nearly 100% of total arsenic. Concentrations generally decreased with increasing distance from the Catahoula Formation (which contains abundant volcanic ash presumed to be the original arsenic source), through the overlying Jasper, Evangeline and Chicot Aquifers. Statistically significant pairwise correlations with arsenic were found for vanadium, silica and potassium, all of which were released during weathering of volcanic sediments and their degradation products. Silica that was co-released with arsenic may compete for sorption sites and reduce the capacity for arsenic adsorption. An important role for variable arsenic source availability was suggested by regional spatial

  18. Towards Sustainable Water Quality In Estuarine Impoundments: The Current State.

    NASA Astrophysics Data System (ADS)

    Wright, J.; Worrall, F.

    Several estuarine impoundment schemes have been built or are proposed in the UK and worldwide. The impounding of estuaries is currently a popular approach to urban regeneration in the UK. By creation of an aesthetically pleasing amenity impound- ment, including the drowning of "unsightly" tidal mud flats, it is hoped that prestige development will be encouraged in the estuarine area. Impounding fundamentally alters the dynamics of estuaries, with consequences in terms of sedimentation patterns and rates, and water quality. The SIMBA Project at- tempts to understand the controls on water quality in impoundments, with a view to- wards long term and sustainable high water quality through good barrage design and management practice. Detailed water quality surveys have been carried out on a total of 79 dates on the Tees, Tawe, Wansbeck and Blyth estuaries. Water quality parameters which have been determined are pH, Eh, dissolved oxygen (DO), biochemical oxygen demand (BOD), conductivity, transparency, suspended solids, alkalinity, temperature, nutri- ents (nitrate+nitrite, ammonium and orthophosphate), and a large range of dissolved metals. Statistical analyses are used to demonstrate the major controls on water qual- ity in impoundments. A distinction is made between total tidal exclusion (freshwater) systems, in which water quality is primarily influenced by external/catchment factors, and partial tidal exclusion systems, in which water quality is processed internally. This internal processing is due to density stratification creating compartments of saline wa- ter in contact with oxygen demanding sediments and isolated from the atmosphere, which leads to conditions of low DO and changes in redox conditions which may lead to release of metals and phosphate from the sediment.

  19. Relating watershed nutrient loads to satellite derived estuarine water quality

    NASA Astrophysics Data System (ADS)

    Lehrter, J. C.; Le, C.

    2015-12-01

    Nutrient enhanced phytoplankton production is a cause of degraded estuarine water quality. Yet, relationships between watershed nutrient loads and the spatial and temporal scales of phytoplankton blooms and subsequent water quality impairments remain unquantified for most systems. This is partially due to a lack of observations. In many systems, satellite remote sensing of water quality variables may be used to supplement limited field observations and improve understanding of linkages to nutrients. Here, we present the results from a field and satellite ocean color study that quantitatively links nutrients to variations in estuarine water quality endpoints. The study was conducted in Pensacola Bay, Florida, an estuary in the northern Gulf of Mexico that is impacted by watershed nutrients. We developed new empirical band ratio algorithms to retrieve phytoplankton biomass as chlorophyll a (chla), colored dissolved organic matter (CDOM), and suspended particulate matter (SPM) from the MEdium Resolution Imaging Spectrometer (MERIS). MERIS had suitable spatial resolution (300-m) for the scale of Pensacola Bay (area = 370 km2, mean depth = 3.4 m) and a spectral band centered at wavelength 709 nm that was used to minimize the effect of organic matter on chla retrieval. The algorithms were applied to daily MERIS remote sensing reflectance (level 2) data acquired from 2003 to 2011 to calculate nine-year time-series of mean monthly chla, CDOM, and SPM concentrations. The MERIS derived time-series were then analyzed for statistical relations with time-series of mean monthly river discharge and river loads of nitrogen, phosphorus, dissolved organic carbon, and SPM. Regression analyses revealed significant relationships between river loads and MERIS water quality variables. The simple regression models provide quantitative predictions about how much chla, CDOM, and SPM concentrations in Pensacola Bay will increase with increased river loading, which is necessary information

  20. A mega-splay fault system and tsunami hazard in the southern Ryukyu subduction zone

    NASA Astrophysics Data System (ADS)

    Hsu, Shu-Kun; Yeh, Yi-Ching; Sibuet, Jean-Claude; Doo, Wen-Bin; Tsai, Ching-Hui

    2013-01-01

    In April 1771, a subduction earthquake generated a great tsunami that struck the south Ryukyu islands and killed ˜12,000 people, whereas its mechanism is still enigmatic (Nakata and Kawana, 1995; Nakamura, 2006; Matsumoto et al., 2009). In this paper, we show its probable source on a mega-splay fault system existing along the southern Ryukyu forearc. Analyses of deep multi-channel seismic reflection profiles indicate that the mega-splay fault system is rising from the summit of a ˜1 km high ridge situated at a ˜5° landward dipping plate interface. An outer ridge marks the seafloor outcrop of the splay fault system and separates the landward inner wedge and the oceanward outer wedge. The inner wedge is uplifting and exhibits widespread normal faulting while the outer wedge shows folded structures. The mega-splay fault system is parallel to the Ryukyu Trench east of 125.5°E and is estimated to be ˜450 km long. The origin of this south Ryukyu mega-splay fault system is ascribed to a resistant subduction of the elevated transverse ridges associated with the subducting portion of the trench-parallel Luzon-Okinawa Fracture Zone. In contrast, no similar splay fault is found west of 125.5°E where the oblique subduction has produced large shear zones along the south Ryukyu forearc. We infer that a thrust earthquake linked to the mega-splay fault system is responsible for the south Ryukyu tsunami. However, another possible scenario of generating a large tsunami affecting the south Ryukyu islands is that the subducted ridge in the western end of the mega-splay fault system nucleated a large earthquake and simultaneously triggered the ˜100 km long E-W trending strike-slip fault west of 125.5°E and induced a southward-dipping tsunami-genic subsidence. In any case, after a quiescence of ˜241 yr, a large earthquake and tsunami is anticipated in the south Ryukyu forearc in the near future.

  1. Sources and processes affecting sulfate in a karstic groundwater system of the Franconian Alb, southern Germany.

    PubMed

    Einsiedl, Florian; Mayer, Bernhard

    2005-09-15

    Chemical and isotope analyses on groundwater sulfate and 3H measurements on groundwaterwere used to determine the sulfate sources and sulfur transformation processes in a heterogeneous karst aquifer of the Franconian Alb, southern Germany. Sulfate was found to be derived from atmospheric deposition. Young groundwater was characterized by high sulfate concentrations and delta34S values similar to those of recent atmospheric sulfate deposition. However, the delta18O values of groundwater SO4(2-) were depleted by several per mil with respect to those of atmospheric deposition. This isotopic shift is indicative of mineralization of carbon-bonded S in the vadose zone of the karst system. In groundwater with mean residence times of more than 60 years, a trend of increasing delta34S values and delta18O values with decreasing sulfate concentrations was observed. This trend could not be solely explained by preindustrial atmospheric sulfate deposition with higher delta34S values, and hence, we conclude that bacterial (dissimilatory) sulfate reduction in the porous matrix of the karst aquifer must have occurred. This process has the potential to contribute to long-term biodegradation of contaminants in the porous rock matrix representing the dominantwater reservoir of the fissured porous karst aquifer.

  2. Uneven distribution of Halobacillus trueperi species in arid natural saline systems of Southern Tunisian Sahara.

    PubMed

    Guesmi, Amel; Ettoumi, Besma; El Hidri, Darine; Essanaa, Jihene; Cherif, Hanene; Mapelli, Francesca; Marasco, Ramona; Rolli, Eleonora; Boudabous, Abdellatif; Cherif, Ameur

    2013-11-01

    The genetic diversity of a collection of 336 spore-forming isolates recovered from five salt-saturated brines and soils (Chott and Sebkhas) mainly located in the hyper-arid regions of the southern Tunisian Sahara has been assessed. Requirements and abilities for growth at a wide range of salinities\\ showed that 44.3 % of the isolates were extremely halotolerant, 23 % were moderate halotolerant, and 32.7 % were strict halophiles, indicating that they are adapted to thrive in these saline ecosystems. A wide genetic diversity was documented based on 16S-23S rRNA internal transcribed spacer fingerprinting profiles (ITS) and 16S rRNA gene sequences that clustered the strains into seven genera: Bacillus, Gracilibacillus, Halobacillus, Oceanobacillus, Paenibacillus, Pontibacillus, and Virgibacillus. Halobacillus trueperi was the most encountered species in all the sites and presented a large intraspecific diversity with a multiplicity of ITS types. The most frequent ITS type included 42 isolates that were chosen for assessing of the intraspecific diversity by BOX-PCR fingerprinting. A high intraspecific microdiversity was documented by 14 BOX-PCR genotypes whose distribution correlated with the strain geographic origin. Interestingly, H. trueperi isolates presented an uneven geographic distribution among sites with the highest frequency of isolation from the coastal sites, suggesting a marine rather than terrestrial origin of the strains. The high frequency and diversity of H. trueperi suggest that it is a major ecosystem-adapted microbial component of the Tunisian Sahara harsh saline systems of marine origin.

  3. SICS: the Southern Inland and Coastal System interdisciplinary project of the USGS South Florida Ecosystem Program

    USGS Publications Warehouse

    ,

    2011-01-01

    State and Federal agencies are working jointly on structural modifications and improved water-delivery strategies to reestablish more natural surface-water flows through the Everglades wetlands and into Florida Bay. Changes in the magnitude, duration, timing, and distribution of inflows from the headwaters of the Taylor Slough and canal C-111 drainage basins have shifted the seasonal distribution and extent of wetland inundation, and also contributed to the development of hypersaline conditions in nearshore embayments of Florida Bay. Such changes are altering biological and vegetative communities in the wetlands and creating stresses on aquatic habitat. Affected biotic resources include federally listed species such as the Cape Sable seaside sparrow, American crocodile, wood stork, and roseate spoonbill. The U.S. Geological Survey (USGS) is synthesizing scientific findings from hydrologic process studies, collecting data to characterize the ecosystem properties and functions, and integrating the results of these efforts into a research tool and management model for this Southern Inland and Coastal System(SICS). Scientists from all four disciplinary divisions of the USGS, Biological Resources, Geology, National Mapping, and Water Resources are contributing to this interdisciplinary project.

  4. Lakota Formation, southern Black Hills, South Dakota: an Early Cretaceous evolving fluvial system

    SciTech Connect

    Dahlstrom D.J.; Fox, J.E.

    1986-08-01

    The fluvial, Early Cretaceous Lakota Formation consists of four spatially and temporally distinct sandstone units in the southern Black Hills and southeastern Powder River basin. Three of these units crop out in proximity to an area of uranium roll-front development (Edgemont mining district) where approximately 2300 wells were drilled and logged. Comparison of the resistivity logs of several of these wells with continuous cores of the Lakota Formation confirms their lithologic sensitivity. These logs (utilized to assist in subsurface facies interpretations where cores were not available), cores, and outcrops are the basis for the following facies interpretations. The discharge, sediment load, and resulting sinuosity of this fluvial system varied substantially throughout the time of Lakota deposition. The oldest unit consists of tabular deposits with complex internal architecture comprised of cross-cutting lateral accretion deposits. Upward-fining grain size, upward-decreasing scale of sedimentary structures, and the angular relationship between lateral accretion surfaces and overlying crevasse-splay deposits support this conclusion. The intermediate unit of ephemeral stream sediments is characterized by abundant pebble- and cobble-strewn erosional surfaces with up to 1.5 m relief, very poor clast sorting, and trough and planar cross-bedding with concave-upward foresets. The youngest unit has a predominance of tabular cross-bedding with back flow climbing ripples and low dispersion of paleocurrent directions, suggesting a relatively straight, bed-load-type channel dominated by trains of sand waves.

  5. Integrated near surface geophysics across the active Mount Marzano Fault System (southern Italy): seismogenic hints

    NASA Astrophysics Data System (ADS)

    Galli, P. A. C.; Giocoli, A.; Peronace, E.; Piscitelli, S.; Quadrio, B.; Bellanova, J.

    2014-01-01

    Here, we describe an original geophysical multi-method approach applied to the Mount Marzano Fault System. This is one of the most hazardous seismogenic faults of the Apennines (Irpinia, southern Italy), and it was responsible for the 1980, Mw 6.9, earthquake, along with many others before. We carried out electrical resistivity tomography (ERT), ground penetrating radar (GPR) measurements, and horizontal-to-vertical spectral ratio (HVSR) microtremor analysis along several common transects designed across the potential and/or certain fault traces. The data obtained from these non-invasive, inexpensive, expeditious methods mutually integrate with and complement each other, providing a valuable subsurface image of the near surface fault architecture. ERT depicts the general shallow image of the fault zone and of the fault-controlled sedimentary basin, with the depth of the buried bedrock cross-correlated through ambient-noise HVSR results. GPR delineates the very shallow geometry of the fault and of the associated deformation. Coupled with previous paleoseismological studies, these data allow the evaluation of some fault parameters and the precise locating of the fault trace, to aid future paleoseismological investigations aimed at seismic risk reduction programs.

  6. Systemic Histomoniasis in a Leucistic Indian Peafowl (Pavo cristatus) from Southern Brazil.

    PubMed

    Michelazzo, Mariana de Mello Zanim; Sasse, João Pedro; de Souza, Marielen; Marutani, Victor Hugo Brunaldi; Sampaio Baptista, Ana Angelita; Garcia, João Luis; Alfieri, Amauri Alcindo; Headley, Selwyn Arlington

    2017-09-01

    The pathological and molecular findings associated with Histomonas meleagridis are described in a leucistic Indian peafowl (Pavo cristatus) from Southern Brazil. The most significant gross findings were multifocal necrotizing hepatitis and diphtheric typhlitis. Histopathologic evaluation of the liver, ceca, kidney, spleen, and small intestine revealed systemic histomoniasis (SH) associated with intralesional and intravascular accumulations of histomonad organisms consistent with H. meleagridis. PCR was used to amplify the DNA of H. meleagridis from the liver, ceca, small intestine, spleen, lungs, and kidneys. Direct sequencing and phylogenetic analyses confirmed that the isolate of the flagellated trichomonad identified from this investigation is more phylogenetically related to H. meleagridis than Tetratrichomonas gallinarum, Tritrichomonas foetus, and Dientamoeba fragilis. These results confirmed the occurrence of SH in this peafowl and add to the diagnosis of this disease in birds from Brazil. This report might represent the first complete identification of spontaneous histomoniasis in a peafowl due to pathological and molecular characteristics and one of the few documented cases of SH in non-commercial birds.

  7. Hydrogeochemistry and statistical analysis applied to understand fluoride provenance in the Guarani Aquifer System, Southern Brazil.

    PubMed

    Marimon, Maria Paula C; Roisenberg, Ari; Suhogusoff, Alexandra V; Viero, Antonio Pedro

    2013-06-01

    High fluoride concentrations (up to 11 mg/L) have been reported in the groundwater of the Guarani Aquifer System (Santa Maria Formation) in the central region of the state of Rio Grande do Sul, Southern Brazil. In this area, dental fluorosis is an endemic disease. This paper presents the geochemical data and the combination of statistical analysis (Principal components and cluster analyses) and geochemical modeling to achieve the hydrogeochemistry of the groundwater and discusses the possible fluoride origin. The groundwater from the Santa Maria Formation is comprised of four different geochemical groups. The first group corresponds to a sodium chloride groundwater which evolves to sodium bicarbonate, the second one, both containing fluoride anomalies. The third group is represented by calcium bicarbonate groundwater, and in the fourth, magnesium is the distinctive parameter. The statistical and geochemical analyses supported by isotopic measurements indicated that groundwater may have originated from mixtures of deeper aquifers and the fluoride concentrations could be derived from rock/water interactions (e.g., desorption from clay minerals).

  8. Geographical Information Systems and canine faecal contamination: the experience in the city of Naples (southern Italy).

    PubMed

    Veneziano, V; Rinaldi, L; Carbone, S; Biggeri, A; Cringoli, G

    2006-06-01

    Geographical Information Systems (GIS) can be used to make transect sampling when non-moving objects are to be counted, involving choosing a line or series of lines along which the counts are to take place. This approach has been used by us in order to study canine faecal contamination in the city of Naples (southern Italy), and to evaluate the consequent presence of canine parasitic elements. A GIS was constructed utilizing the geo-referenced digital photographs and the cadastral maps of Naples. In order to uniformly evaluate the canine faecal contamination throughout the city, a grid representing sub-areas of 1 km x 700 m was overlaid on the city map within the GIS. The territory of Naples was divided in 218 equal, rectangular sub-areas. In each sub-area a 1 km transect was drawn, and digitalized on-screen in the GIS. Canine faeces (copros in Greek) were counted along the transects in 143 sub-areas. In these sub-areas, 415 copros were collected and examined. Out of the 143 sub-areas, 141 contained canine copros. The results of the negative binomial regression model showed a positive association between the number of copros and the human population density. Out of the total of 415 copros, 70 (16.9%) were positive for parasitic elements; eggs of Toxocara canis, Toxascaris leonina, Ancylostoma caninum and Trichuris vulpis were found, as well as oocysts of Isospora canis.

  9. Sheep production and marketing system in southern Ethiopia: the case of Awassazuria district.

    PubMed

    Tadesse, Estefanos; Negesse, Tegene; Abebe, Girma

    2015-10-01

    A survey was conducted in Awassazuria district of southern Ethiopia to characterize sheep production system. A structured questionnaire was used to collect data. Using purposive sampling, a total of 120 households from the district were included in the survey. Collected data were analyzed using descriptive statistics. Result indicated that Kajima neighbourhood has more (p<0.05) grazing land than the others. Communal grazing, roadside grazing, enset (false banana, Ensete ventricosum), banana leaf and private grazing land were major feed resources for sheep. Lake Awassa and tap water were permanent water sources. Watering frequency of sheep varies from once a day to once in 4 days. Sheep are primarily kept to generate income and equilibrate benefit and risk and for home consumption. The criteria used by the households for purchase and sale of sheep are physical characteristics (coat colour, horn and tail) (46.7 %), body conformation (35 %), age (10.8 %) and known local ecotype (7.5 %). The reasons of slaughter of sheep include festival (55 %), childbirth (18.3 %), wedding (12.5 %), mutton for home (9 %), circumcision (5 %) and for guest (1.7 %). Farmers fatten sheep for New Year (60 %), Easter (30.8 %), Christmas and Arefa (Eid al-Adha celebration (Feast of the Sacrifice); <10 %). The reasons for expansion of sheep flock in the future were market price, high market demand, immediate return, ease of management, equilibrium between benefits and risks and suitability for home consumption, ranked in decreasing order of importance. The sheep production in southern Ethiopia is constrained by shortage of grazing land (23.3 %), recurrent drought (17.5 %), disease and parasite (15 %), marketing (10.8 %), water shortage (9 %) and other constraints including predators and lack of input, capital and lack of extension service. The presence of diversified and environmentally adaptable sheep breeds, high demand of mutton in the Awassa town and presence of nutritious and unutilized

  10. Development of a Unified Hydrostratigraphic Framework for the Floridan Aquifer System in Central and Southern Florida

    NASA Astrophysics Data System (ADS)

    Reese, R. S.

    2008-05-01

    The mostly carbonate Floridan aquifer system (FAS) of central and southern Florida is a widely used resource with a complex hydrostratigraphic framework that is managed primarily in a subregional context according to water management jurisdictional boundaries. As use of the FAS increases, a consistent regional hydrostratigraphic framework is needed for effective management across these boundaries. Stratigraphic marker horizons within and near the top of FAS were delineated and mapped to develop a preliminary, correlative stratigraphic framework. This framework was used to identify and determine aquifers, subaquifers, and confining units and map their spatial distribution. These horizons are based on lithologic changes and geophysical log signatures identified in previous studies, and they were extended throughout the study area primarily by correlation of natural gamma-ray logs. The FAS consists of the Upper Floridan aquifer, middle confining unit, and Lower Floridan aquifer. A regional, productive zone is delineated and informally referred to as the Avon Park permeable zone. This zone is present over most of the study area and is characterized by thick units of dolostone with interbedded limestone and high fracture permeability. The zone has been identified in different regions in previous studies, either as the upper part of the Lower Floridan aquifer or as the lower part of the Upper Floridan aquifer. In this study it is generally considered to be within the middle confining unit. Transmissivity of the Avon Park permeable zone, a major source of water supply, generally ranges from less than 1x104 up to 1.6x106 ft2/day, and is greatest in central Florida where dolomite is developed as a major component of the zone. A large area of low transmissivity (less than 105 ft2/day) in southern Florida coincides with an area where limestone is the predominant lithology within the zone. Major uses of the FAS now include withdrawal for public and agricultural supply

  11. Structure of the Subduction System in Southern Peru from Seismic Array Data

    NASA Astrophysics Data System (ADS)

    Phillips-Alonge, Kristin

    Southern Peru represents a subduction transition region from normal subduction in the southernmost part of Peru to flat slab subduction in central Peru. In order to learn more about the structure of southern Peru, causes of flat slab subduction, and the nature of the transition from normal to flat slab subduction, we installed three seismic arrays utilizing a total of about 100 broadband stations. The first installed array samples the normal subduction region, while the second samples the transition from normal to flat subduction, and the third samples the flat slab region near where the Nazca Ridge is presently subducting. Data from teleseismic events greater than 30 degrees distance from Peru was analyzed using the receiver function method that makes use of P to S converted phases at interfaces such as the Moho to provide information about the structure directly beneath each station. A strong signal from the Moho was observed for each array and was found to have a maximum depth of around 75 km beneath the Altiplano. The average crustal Vp/Vs ratio was also estimated and was found to have an average value of around 1.75 beneath the Altiplano. The shape of the slab was also clarified for the three arrays. The transition from normal to flat slab subduction appears to be a contortion rather than a break in the slab. In addition to those signals, a positive impedance midcrustal signal at about 40 km depth was widely observed for stations on the eastern side of the arrays. The midcrustal signal is indicative of a velocity increase in the lower crust and is suggested to be an observation of the underthrusting Brazilian shield which would have implications for the timing of uplift in the Andes. Finite difference modeling with velocity models that include a midcrustal structure produces synthetics which are consistent with receiver function observations. Receiver function results and other related methods provide a simple way of making direct observations of key

  12. Serving data from the SCAR Southern Ocean Observing System (SOOS) using the SeaDataNet infrastructure

    NASA Astrophysics Data System (ADS)

    de Bruin, T.

    2009-04-01

    The importance of the Southern Ocean to the global climate system and the uniqueness of its ecosystems are well known. The region is remote and logistically difficult to access and thus is one of the least sampled regions on the planet. Design and implementation of an observing system that encompasses physical, biogeochemical and ecological processes is therefore a formidable challenge. The Scientific Committee on Antarctic Research (SCAR) has, jointly with the SCAR/SCOR Expert Group on the Southern Ocean, started the process to develop such a Southern Ocean Observing System (SOOS). The goals are to address major scientific questions and to coordinate measurement campaigns to do so. The SCAR Standing Committee on Antarctic Data Management (SC-ADM) is responsible for the design of the SOOS data flow system or Virtual Observatory, which will be used to archive and exchange data. SC-ADM is working in close cooperation with National Oceanographic Data Centres (NODCs), the International Oceanographic Data and Information Exchange Committee of the Intergovernmental Oceanographic Commission (IOC-IODE) and the IOC-WMO Joint Committee on Oceanography and Marine Meteorology (JCOMM). This presentation will focus on the European SeaDataNet project (www.seadatanet.org), which provides a real-world, operational model for access to and exchange of data from big observing systems such as the proposed SOOS and the European Marine Observation and Data Network (EMODNet).

  13. 76 FR 10338 - Evaluation of State Coastal Management Programs and National Estuarine Research Reserves

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-24

    ... National Estuarine Research Reserves AGENCY: National Oceanic and Atmospheric Administration (NOAA), Office...-Aransas (Texas) National Estuarine Research Reserve. The National Estuarine Research Reserve evaluation..., subpart E and part 923, subpart L. Evaluation of a National Estuarine Research Reserve requires findings...

  14. Identifying sources of acidity and spatial distribution of acid sulfate soils in the Anglesea River catchment, southern Australia

    NASA Astrophysics Data System (ADS)

    Wong, Vanessa; Yau, Chin; Kennedy, David

    2015-04-01

    Globally, coastal and estuarine floodplains are frequently underlain by sulfidic sediments. When exposed to oxygen, sulfidic sediments oxidise to form acid sulfate soils, adversely impacting on floodplain health and adjacent aquatic ecoystems. In eastern Australia, our understanding of the formation of these coastal and estuarine floodplains, and hence, spatial distribution of acid sulfate soils, is relatively well established. These soils have largely formed as a result of sedimentation of coastal river valleys approximately 6000 years BP when sea levels were one to two metres higher. However, our understanding of the evolution of estuarine systems and acid sulfate soil formation, and hence, distribution, in southern Australia remains limited. The Anglesea River, in southern Australia, is subjected to frequent episodes of poor water quality and low pH resulting in closure of the river and, in extreme cases, large fish kill events. This region is heavily reliant on tourism and host to a number of iconic features, including the Great Ocean Road and Twelve Apostles. Poor water quality has been linked to acid leakage from mining activities and Tertiary-aged coal seams, peat swamps and acid sulfate soils in the region. However, our understanding of the sources of acidity and distribution of acid sulfate soils in this region remains poor. In this study, four sites on the Anglesea River floodplain were sampled, representative of the main vegetation communities. Peat swamps and intertidal marshes were both significant sources of acidity on the floodplain in the lower catchment. However, acid neutralising capacity provided by carbonate sands suggests that there are additional sources of acidity higher in the catchment. This pilot study has highlighted the complexity in the links between the floodplain, upper catchment and waterways with further research required to understand these links for targeted acid management strategies.

  15. Structure of the zooplankton communities in the region of the Ob River's estuarine frontal zone

    NASA Astrophysics Data System (ADS)

    Flint, M. V.; Semenova, T. N.; Arashkevich, E. G.; Sukhanova, I. N.; Gagarin, V. I.; Kremenetskiy, V. V.; Pivovarov, M. A.; Soloviev, K. A.

    2010-10-01

    The studies were carried out on September 27-30, 2007, in the area of the Ob estuarine frontal zone and over the adjacent inner Kara Sea shelf. Based upon the latitudinal changes in the salinity, the 100 nautical mile wide estuarine frontal zone was marked out. The frontal zone was inhabited by a specific zooplankton community dominated by species that occurred outside the frontal zone in only minor amounts. The biomass of the mesozooplankton averaging 984 mg/m3 in the frontal zone exceeded by 1.5 and 6 times the corresponding values in the inner desalinated area of the estuary and the adjacent areas of the Kara Sea shelf. At the inner southern periphery of the frontal zone, at maximal latitudinal salinity gradients (>2 psu per mile), the maximal development of the mesoplankton with the mean biomass for the water column of 3.1 g/m3 (37 g/m2) and up to 5.8 g/m3 in the subpycnocline layer was observed. The latitudinal extension of the biomass in the maximum zone did not exceed 10 miles. More than 90% of the maximum was composed of herbivorous zooplankton with the strong domination of the copepod Limnocalanus macrurus. The daily consumption within the zooplankton maximum area was estimated at 820 mgC/m2 per day. This value exceeds by two orders of magnitude the local primary production. At that level of consumption, the available phytoplankton biomass was consumed by grazers in less than 8 hours (!). A zooplankton aggregation at the southern periphery of the estuarine front exists due to the advection of phytoplankton from the adjacent river zone. The aggregation forms a natural pelagic biofilter where new allochthonous organic matter delivered by the river flow is accumulated and high secondary production is formed on its basis. An anomalously high concentration of planktic predatory Parasagitta elegans with biomass of over 1 g/m3 (46% of the total zooplankton biomass) was associated with the outer northern periphery of the estuarine frontal zone.

  16. Role of native and exotic woody vegetation in soil restoration in active gully systems (southern Ecuador)

    NASA Astrophysics Data System (ADS)

    Borja Ramon, Pablo; Alvarado Moncayo, Dario; Vanacker, Veerle; Cisneros, Pedro; Molina, Armando; Govers, Gerard

    2015-04-01

    Revegetation projects in degraded lands have the potential to recover essential soil functions. If vegetation restoration is combined with bioengineering techniques, such as the construction of retention dams in active gully systems, soil restoration could be enhanced. One important aspect of this process is the role of vegetation on restoration of soil chemical and physical properties. There is currently a lack of knowledge on the potential of soil restoration in active badland systems, as most studies have concentrated on the direct and visible effect of revegetation on erosion control. The aim of this study is to evaluate the role of revegetation and bioengineering works on the restoration of soil physical and chemical properties. The analyses are realized in a highly degraded area of 3 km2, located in the lower part of the Loreto catchment (Southern Ecuadorian Andes). First, the soil physical and/or chemical parameters that are most sensitive to track environmental change were evaluated. Second, the role of vegetation on soil restoration was quantified. . Soil samples were taken in sites with different vegetation cover, land use and physiographic position. The following physical and chemical parameters were measured: volumetric water content (θsat, θact), bulk density, pH, texture, organic matter, C and N content. Our first results do not show a clear relationship between volumetric water content at saturation (θsat), bulk density, or C content. The saturation water content does not vary significantly between different sites, or land use types. However, significant differences are found between sites at different stages of restoration; and this for most chemical and physical soil properties. Vegetation cover (%) appears to exert a strong control on the C content in the mineral soils. The highest C values are found in soils of forest plantations with Eucalyptus and Pinus species. These plantations are located in areas that were previously affected by active

  17. Turkish Straits System and Southern Black Sea: Exchange. Mixing and Shelf / Canyon Interactions

    NASA Astrophysics Data System (ADS)

    Özsoy, Emin; Gürses, Özgür; Tutsak, Ersin

    2015-04-01

    Based largely on an experiment employing high-resolution measurements carried out in June-July 2013 and re-interpretation of past experiments, the oceanographic variability of the exchange through the Turkish Straits System (TSS) and the interactions with the southern Black Sea are revealed through CTD, ADCP, oxygen and light transmission measurements. The exchange flow is primarily governed by the complex topography spanning two narrow straits, wide continental shelf regions, steep slopes and numerous canyons connecting deep basins. Water properties and currents in the high energy environment depends on the mosaic of fine-scale processes and pathways. The TSS, often approximated as a two-layer system has a hydraulically controlled, upper ocean and straits intensified regime, leading to surface jets and bottom plumes participating in mixing and renewal processes. The exit of the 'Mediterranean effluent' onto the Black Sea past a sill overflow from the Bosphorus passes through two subsequent hydraulic jumps and proceeds along a narrow canyon that veers to the west clear of the greater Bosphorus Canyon finally cascading down the few small canyons. A diffusive spread from the bottom vein of salty water reforms to the east and spills down the Bosphorus Canyon. The suspended particulate signature of the cascade, as well as its influence in hydrography is traced over the shelf and slope waters and through the numerous canyons into deep water where the reformed flow is found to sustain signatures of the past evolution of intrusive waters. An evaluation of the processes is given with reference to model development carried out in parallel to the analyses of the measurements.

  18. Pliocene-Quaternary orogenic systems in Central Mediterranean: The Apulia-Southern Apennines-Tyrrhenian Sea example

    NASA Astrophysics Data System (ADS)

    Milia, Alfonsa; Torrente, Maurizio M.; Iannace, Pietro

    2017-08-01

    In the Central Mediterranean the Africa-Eurasia convergence led to the development of complex orogenic systems and back-arc basins. Throughout Pliocene-Quaternary times the Southern Apennines accretionary prism migrated toward the Apulia foreland and, contemporaneously, the Tyrrhenian Sea back-arc basin opened. In this study, we investigated the offshore of the southern Apulia foreland and the Southern Apennines. Using seismic reflection profiles and well data in a dedicated GIS software, we made a detailed stratigraphic analysis, reconstructed the structural pattern, and built 2-D geological models of the main geological surfaces. The structure of the Apulia region formed during two main tectonic stages: lower Pleistocene complex extensional faulting developed in a transtensional regime and middle-upper Pleistocene transpression/shortening. The Southern Apennines accretionary prism developed through the Pliocene-early lower Pleistocene and was overprinted by late lower Pleistocene-middle Pleistocene NW-SE sinistral faults. Through linking new data from the accretionary prism and the foreland with previous information from the Tyrrhenian Sea back-arc, we provide an original interpretation for the relationships between the various provinces that make the Central Mediterranean crustal puzzle and reconstruct the main phases of the evolution of its Pliocene-Quaternary orogenic cycle. We recognized collisional stages of uncoupled plates, followed by late lower-middle Pleistocene postcollisional stages of coupled continental plates. This Pleistocene plate reorganization of Central Mediterranean was probably due to the rupture of the Apulia/Ionian slab or to NNW intraplate shortening transmitted from Africa.

  19. Efficacy of two systemic insecticides injected into loblolly pine for protection against southern pine bark beetles (Coleoptera: Curculionidae).

    PubMed

    Grosman, Donald M; Clarke, Stephen R; Upton, William W

    2009-06-01

    We evaluated the efficacy of systemic insecticides emamectin benzoate and fipronil for preventing mortality of individual loblolly pines, Pinus taeda L., as a result of attacks by southern pine bark beetles (Coleoptera: Curculionidae, Scolytinae) for two consecutive years in Mississippi (2005-2006) and Alabama (2006-2007). Trees were injected once in the spring of 2005 (Mississippi) or 2006 (Alabama) and then were baited with species-specific bark beetle lures several weeks later. The southern pine beetle, Dendroctonus frontalis Zimmermann, was the target species but was changed to Ips spp. in Mississippi (but not Alabama) the second year because of few southern pine beetle attacks on baited trees. Single injections of emamectin benzoate were effective in reducing tree mortality caused by bark beetles compared with untreated checks. Although less effective overall, fipronil also significantly reduced tree mortality from southern pine beetle compared with the checks during the second year in Alabama. Tree mortality continued well after the lures had been removed. Evaluations of bolts taken from experimental trees killed in 2006 indicated that emamectin benzoate effectively prevented parent bark beetle gallery construction and that fipronil significantly reduced lengths of galleries constructed by adult beetles, brood development, and emergence, compared with checks. In contrast, neither insecticide treatment prevented the bark beetles from inoculating blue stain fungi, Ophiostoma spp., into treated trees.

  20. Latest Pleistocene advance and collapse of the Matanuska - Knik glacier system, Anchorage Lowland, southern Alaska

    NASA Astrophysics Data System (ADS)

    Kopczynski, Sarah E.; Kelley, Samuel E.; Lowell, Thomas V.; Evenson, Edward B.; Applegate, Patrick J.

    2017-01-01

    At the end of the last ice age, glacier systems worldwide underwent dramatic retreat. Here, we document the advance and retreat of a glacier system with adjacent marine- and land-based components during the latter part of the Termination. We utilize three lines of evidence: lithologic provenance, geomorphic mapping, and radiocarbon ages derived from lake cores to reconstruct glacier extent and timing of advance and retreat within our study area centered at N 61.50°, W 149.50°, just north of Anchorage, Alaska. Two glaciers, sourced in the Talkeetna and Chugach Mountains, flowed down the Matanuska and Knik Valleys forming a coalesced lobe that advanced onto the Anchorage Lowlands and terminated at Elmendorf Moraine. We use the presence of lithologies unique to the Matanuska catchment in glacial drift to delineate the paleoflow lines and to estimate the suture line of the two glacier systems. The eastern side of the lobe, attributed to ice flow from the Knik Valley, was in contact with elevated marine waters within the Knik Arm fjord, and thus retreat was likely dominated by calving. Geomorphic evidence suggests the western side of the lobe, attributed to ice flow from Matanuska Valley, retreated due to stagnation. We constrain retreat of the combined Matanuska and Knik lobe with thirteen new radiocarbon ages, in addition to previously published radiocarbon ages, and with geomorphic evidence suggesting the retreat occurred in two phases. Retreat from the Elmendorf Moraine began between 16.8 and 16.4 ka BP. A second, faster retreat phase occurred later and was completed by 13.7 ka BP. With the 140 km of total retreat occurring over ∼3000 years or less. This pattern of glacial advance and retreats agrees well with the deglacial histories from the southern sectors of the Cordilleran Ice Sheet, as well as many other alpine glacier systems in the western U.S. and northern Alaska. This consistent behavior of glacier systems may indicate that climate oscillated over

  1. Impact of estuarine pollution on birds

    USGS Publications Warehouse

    Blus, L.J.; Wiemeyer, Stanley N.; Kerwin, J.A.; Stendell, R.C.; Ohlendorf, H.M.; Stickel, L.F.

    1977-01-01

    Pollution of estuaries affects bird populations indirectly through changes in habitat and food supply. The multi-factor pollution of Chesapeake Bay has resulted in diminution of submerged aquatic plants and consequent change in food habits of the canvasback duck. Although dredge-spoil operations can improve wildlife habitat, they often result in its demise. Pollution of estuaries also affects birds directly, through chemical toxication, which may result in outright mortality or in reproductive impairment. Lead from industrial sources and roadways enters the estuaries and is accumulated in tissues of birds. Lead pellets deposited in estuaries as a result of hunting are consumed by ducks with sufficient frequency .to result m large annual die-offs from lead poisoning. Fish in certain areas, usually near industrial sources, may contain levels of mercury high enough to be hazardous to birds that consume them. Other heavy metals are present in estuarine birds, but their significance is poorly known. Oil exerts lethal or sublethal effects on birds by oiling their feathers, oiling eggs and young by contaminated parents, and by ingestion of oil-contaminated food. Organochlorine chemicals, of both agricultural and industrial origin, travel through the food chains and reach harmful levels in susceptible species of birds in certain estuarine ecosystems. Both outright mortality and reproductive impairment have occurred.

  2. Estimating flood exceedance probabilities in estuarine regions

    NASA Astrophysics Data System (ADS)

    Westra, Seth; Leonard, Michael

    2016-04-01

    Flood events in estuarine regions can arise from the interaction of extreme rainfall and storm surge. Determining flood level exceedance probabilities in these regions is complicated by the dependence of these processes for extreme events. A comprehensive study of tide and rainfall gauges along the Australian coastline was conducted to determine the dependence of these extremes using a bivariate logistic threshold-excess model. The dependence strength is shown to vary as a function of distance over many hundreds of kilometres indicating that the dependence arises due to synoptic scale meteorological forcings. It is also shown to vary as a function of storm burst duration, time lag between the extreme rainfall and the storm surge event. The dependence estimates are then used with a bivariate design variable method to determine flood risk in estuarine regions for a number of case studies. Aspects of the method demonstrated in the case studies include, the resolution and range of the hydraulic response table, fitting of probability distributions, computational efficiency, uncertainty, potential variation in marginal distributions due to climate change, and application to two dimensional output from hydraulic models. Case studies are located on the Swan River (Western Australia), Nambucca River and Hawkesbury Nepean River (New South Wales).

  3. Estuarine Salinity Mapping From Airborne Radiometry

    NASA Astrophysics Data System (ADS)

    Walker, J. P.; Gao, Y.; Cook, P. L. M.; Ye, N.

    2016-12-01

    Estuaries are critical ecosystems providing both ecological habitat and human amenity including boating and recreational fishing. Salinity gradients, caused by the mixing of fresh and salt water, exert an overwhelming control on estuarine ecology and biogeochemistry as well as being a key tracer for model calibration. At present, salinity monitoring within estuaries typically uses point measurements or underway boat-based methods, which makes sensing of localised phenomena such as upwelling of saline bottom water difficult. This study has pioneered the use of airborne radiometry (passive microwave) sensing as a new method to remotely quantify estuarine salinity, allowing rapid production of high resolution surface salinity maps. The airborne radiometry mapping was conducted for the Gippsland Lakes, the largest estuary in Australia, in February, July, October and November of 2015, using the Polarimetric L-band Microwave Radiometer (PLMR). Salinity was retrieved from the brightness temperature collected by PLMR with results validated against boat sampling conducted concurrently with each flight. Results showed that the retrieval accuracy of the radiative transfer model was better than 5 ppt for most flights. The spatial, temporal and seasonal variations of salinity observed in this study are also analysed and discussed.

  4. Beroe gracilis (Ctenophora) from the Humboldt Current System: first occurrence of this species in the southern hemisphere.

    PubMed

    Oliveira, Otto M P; Feliú, Guillermo; Palma, Sergio

    2014-07-04

    Beroe gracilis Künne, 1939 is a small neritic ctenophore, previously recorded only from cold waters of the northern hemisphere. The present study provides the first record of the species in the southern hemisphere, found in the surface layer of the Humboldt Current System off the central Chilean coast (32°-36.5° S). A complete description of this material is provided.

  5. The Role of Physical-Chemical Factors in Structuring Subtidal Marine and Estuarine Benthos.

    DTIC Science & Technology

    1983-06-01

    benthic habitats and environmental factors that structure them will focus on the east coast and Gulf of Mexico estuarine system. Contrasts and...34 Benthic Infaunal Variability on a Transect in the Gulf of Mexico ," Estur. Coastal Mar. Sci., 10:1-14. Fonseca, M. S., Kenworthy, W. J., Homziak, J...Kings- ton 1978; Flint and Holland 1980). In general, transect studies of shelf benthos from the east coast and Gulf of Mexico have shown that density

  6. Structural Control of the Ubinas-Huaynaputina-Ticsani System: A Large, Young Silicic Magmatic System in Southern Peru

    NASA Astrophysics Data System (ADS)

    Lavallee, Y.; de Silva, S. L.; Salas, G.; Byrnes, J.

    2003-12-01

    The location of magma reservoirs and volcanic centers are commonly controlled by tectonic structures (e.g., Hutton, 1989; Gibbons and Moreno, 2002). In the Central Volcanic Zone, southern Peru, volcanism is mainly associated with the major NNW-SSE sinistral strike slip fault systems underlying the main volcanic arc. However, a group of related silicic volcanoes was recently discovered which crop out beyond the arc; the Ubinas-Huaynaputina-Ticsani system (UHTS). Characterizing its dimension and tectonic influences are crucial in order to evaluate corresponding volcanic hazards. Potentially active fault systems as well as major tectonic features in and around the UHTS were mapped and the structural framework was elucidated. The UHTS is located within a north to south extensional domain housing three fault systems: (1) the arc related NNW-SSE fault system, intersected by (2) a unique N-S en echelon strike slip fault system, and (3) a minor W-E fault system. Identification of confined Cretaceous volcanics known as the Matalaque formation indicated the presence of a narrow graben that developed on the western side of the N-S fault system. Interestingly all volcanic centers are positioned at the intersection of the NNW-SSE faults with the N-S faults. Seismic records revealed the concentration of seismicity around depths ranging between 20 and 33 km. The position of the UHTS is dictated by the intersection of the NNW-SSE and N-S major en echelon strike slip fault systems. We propose the role of the NNW-SSE fault as a deep pathway for magma ascent whereas the N-S strike-slip motion allowed the release of stress and deviation of magma, which scattered and ponded between adjacent NNW-SSE faults at ~30 km depths. Based on the vent distribution, we estimated the size of the silicic magma reservoir as approximately 40 x 60 km; this is a reasonable estimate since the withdrawal of a volume larger than 10 km3 was not significant enough to produce an equivalent caldera collapse

  7. Geomorphic features off southern California as seen by GLORIA side-scan sonar system

    SciTech Connect

    Edwards, B.D.; Field, M.E.; Carlson, P.R.; Kenyon, N.H.

    1985-02-01

    Approximately 165,000 km/sup 2/ of the sea floor off southern California was mapped during May 1984, as part of a USGS/IOS cooperative program to study the newly proclaimed Exclusive Economic Zone (EEZ) of the US Pacific margin. The area was insonified using the Geological Long-Range Inclined Asdic (GLORIA), a long-range side-scan sonar system. Images were corrected for water-column velocity anomalies, for along-track distortions caused by acoustic ray travel paths. A photomosaic of the overlapping sonographs has been compiled at a scale of 1:375,000. The basins of the inner California continental borderland are characterized by both sinuous channel and fan complexes and by feathery acoustic patterns indicating active sediment transport. In contrast, outer borderland basins appear to be more sediment starved, exhibit large areas of sediment failure, and show significant structural influence. West of Patton Escarpment, the sonographs are dominated by acoustic patterns showing volcanic ridges and seamounts and by deposits of the Monterey and Arguello fans. Arguello fan, for example, exhibits multiple sinuous channels that have transported sediment 60 km south from the canyon mouth. These channels coalesce into a single 100-km long, westward-meandering channel that terminates in a 600-m deep box canyon. A zone of sediment failure is identifiable on the north levee of an upper fan channel. Tectonic trends associated with oceanic basement are highlighted by the terminus of the west-trending Murray Fracture Zone and by the prevailing northeast trend of volcanic ridge and seamount chains.

  8. Paleomagnetic Data Bearing on the Eastern and Southern Boundaries of the Walker Lane Belt Transfer System

    NASA Astrophysics Data System (ADS)

    Grow, J. S.; Geissman, J. W.; Oldow, J. S.

    2007-12-01

    In west-central Nevada, a transfer zone, which initiated in the mid-Miocene, presently links, via the Mina Deflection, right-lateral faults of the Eastern California Shear Zone to the south and the Central Nevada Seismic Belt and Walker Lane to the north. This transfer zone, the early inception of which is characterized by moderate (20-30°) clockwise crustal rotations previously identified (e.g., Candelaria Hills and surrounding ranges), along with right-lateral structures to the south and north, are part of a diffuse zone of intracontinental deformation that accommodates some 25 percent of the motion between the Pacific and North American plates. Although the northern and western boundaries of the transfer zone are relatively well defined by paleomagnetic data, the eastern and southeastern boundaries remain poorly constrained. Additional paleomagnetic data are being obtained from mid-to-late Tertiary volcanic rocks, presumably lying within (e.g., Montezuma Range, Palmetto Mountains, Monte Cristo Range) and outside (e.g., Goldfield Hills, San Antonio Mountains, Slate Ridge) of the transfer zone. Areas outside of the transfer zone are inferred to have not undergone any appreciable rotation since its inception. Volcanic rocks as well as shallow intrusions ranging in age from Oligocene to mid-Pliocene have been sampled (N=187) from inside and outside of the inferred southern and eastern boundaries of the transfer zone. Overall, the collection responds very favorably to progressive demagnetization; initial results are tentatively interpreted as suggesting the absence of appreciable rotation of the San Antonio Range (Tonopah, Nevada area and farther north). The extent to which areas near the eastern and southeastern boundaries have been rotated is under investigation. These data will aid in a better understanding of differential block rotation and tilting throughout the development of the west-central Nevada transfer system from the mid-Miocene to late Pliocene.

  9. Inferring Upper Ocean Dynamics from Horizontal Wavenumber Spectra in the Southern California Current System

    NASA Astrophysics Data System (ADS)

    Chereskin, T. K.; Gille, S. T.; Rocha, C. B.; Menemenlis, D.

    2016-02-01

    At the largest horizontal scales (> 100 km), the surface kinetic energy of the ocean appears dominated by a regime of balanced geostrophic motions. At the smallest scales, it transitions to a regime where unbalanced motions (such as internal waves, mixed-layer instabilities, etc.) dominate the surface kinetic energy. The length scale at which the transition occurs depends on the relative energies of balanced and unbalanced motions, which in turn display significant geographic variability. Wavenumber spectra in the upper ocean have been hypothesized to have slopes consistent with either quasi-geostrophic (QG) or surface quasi-geostrophic (SQG) theory. In previous analyses of repeat-track shipboard acoustic Doppler Current profiler (ADCP) velocity observations in the Gulf Stream and the Antarctic Circumpolar Current, spectral slopes were more consistent with QG than SQG theory for length scales between 40 km and 200 km. For scales less than 40 km, the spectra deviated from both QG and SQG theory, and this was attributed in part to internal wave effects. A spectral Helmholtz decomposition was used to split the kinetic energy spectra into rotational and divergent components, identified with balanced and ageostrophic motions, respectively. The California Current System (CCS) provides a contrasting environment characterized by a weak mean flow and an energetic meso- and submeso- scale. It is a nonlinear regime where the amplitude of eddies can be as large as the total steric height increase across the California Current, and hence southward flow in the CCS can, and often is, disrupted by its eddies. This study uses 10 years of shipboard ADCP observations collected on the quarterly cruises of the California Cooperative Oceanic Fisheries Investigations. Horizontal wavenumber spectra from 36 cruises along 6 repeated tracks in the southern CCS that extend from the coast to the subtropical gyre are used to diagnose the dominant governing dynamics at meso- to submeso- scales

  10. Analysing connectivity through landslide-channel geomorphic coupling in a large drainage system of Southern Romania

    NASA Astrophysics Data System (ADS)

    Jurchescu, Marta

    2014-05-01

    Unlike creep, splash erosion and linear erosion which sometimes are called "continuous" slope processes, since they are perceived as causing relatively continuous erosion on slopes and a rather rapid transport towards river channels, mass movement processes, excepting flows, have a discontinuous behavior, manifesting stochastically on time intervals ranging from one year to tens of years, while the displaced material can remain suspended in different parts of the slope forming sediment stores. It is obviously why estimating the sediment delivered to the river network by landslides becomes a difficult task. Landslide control on channel dynamics is just one of the several forms of hillslope-channel coupling. Landslide-channel connectivity is relevant for understanding the way landslides are contributing to the sediment flux within catchments and how their study should be integrated in the estimation of sediment budgets. This paper explores the geomorphic coupling of landslides with river channels based on an extensive landslide inventory. The study area is a large drainage basin (> 2400 km2) in southern Romania encompassing four different geomorphic units (mountains, hills, piedmont and plain). The region is highly affected by a wide range of geomorphic processes which contribute to supplying sediments to the drainage network. The presence of a reservoir at the river outlet emphasizes the importance of estimating sediment budgets, the first stage of which consists in studying sediment sources. High sediment transport is associated to flash floods, a fraction of which is due to the slope failures occurring in response to the undercutting of river channels. Nominal classification systems as well as quantitative measures available in the connectivity literature are adopted here to describe the landslides-channels contact zones. Characteristics of the geomorphic coupling interfaces are further linked to the resulting geomorphic effects of landslides on the drainage

  11. The 2014-2015 Warming Anomaly in the Southern California Current System: Glider Observations

    NASA Astrophysics Data System (ADS)

    Zaba, K. D.; Rudnick, D. L.

    2016-02-01

    During 2014-2015, basin-wide patterns of oceanic and atmospheric anomalies affected surface waters throughout the North Pacific Ocean. We present regional physical and biological effects of the warming, as observed by our autonomous underwater gliders in the southern California Current System (SCCS). Established in 2006, the California Glider Network provides sustained subsurface observations for monitoring the coastal effects of large-scale climate variability. Along repeat sections that extend to 350-500 km in offshore distance and 500 m in depth, Spray gliders have continuously occupied CalCOFI lines 66.7, 80, and 90 for nearly nine years. Following a sawtooth trajectory, the gliders complete each dive in approximately 3 hours and over 3 km. Measured variables include pressure, temperature, salinity, chlorophyll fluorescence, and velocity. For each of the three lines, a comprehensive climatology has been constructed from the multiyear timeseries. The ongoing surface-intensified warming anomaly, which began locally in early 2014 and persists through present, is unprecedented in the glider climatology. Reaching up to 5°C, positive temperature anomalies have been generally confined to the upper 50 m and persistent for over 20 months. The timing of the warming was in phase along each glider line but out of phase with equatorial SST anomalies, suggesting a decoupling of tropical and mid-latitude dynamics. Concurrent physical oceanographic anomalies included a depressed thermocline and high stratification. An induced biological response was apparent in the deepening of the subsurface chlorophyll fluorescence maximum. Ancillary atmospheric data from the NCEP North American Mesoscale (NAM) model indicate that a combination of surface forcing anomalies, namely high downward heat flux and weak wind stress magnitude, caused the unusual warm, downwelling conditions. With a strong El Niño event in the forecast for winter 2015-2016, our sustained glider network will

  12. Covariability of zooplankton gradients with glider-detected density fronts in the Southern California Current System

    NASA Astrophysics Data System (ADS)

    Powell, Jesse R.; Ohman, Mark D.

    2015-02-01

    Fronts represent sharp boundaries between water masses, but seasonal and interannual variation in their occurrence and effects on the distributions of pelagic organisms are poorly understood. This study reports results from six years of ocean front observations (2006-2011) along two transect lines across the Southern California Current System (SCCS) using autonomous Spray ocean gliders. During this time, 154 positive near-surface density fronts were identified within 124 completed transects consisting of nearly 23,000 vertical profiles. The incidence of surface density fronts showed distinct seasonality along line 80 off Pt. Conception, with fewer fronts occurring during winter months and more numerous fronts in the nearshore and during spring, summer and fall. On line 90, fronts were the least common nearshore and most frequent in a transitional region offshore. Horizontal density gradients in the surface layer (0-50 m) were significantly correlated with horizontal gradients in surface layer Chlorophyll-a (Chl-a) fluorescence, as well as with mean volume backscatter (MVBS) recorded by a 750 kHz acoustic Doppler profiler. Density fronts were not only zones of rapidly changing phytoplankton and zooplankton biomass concentrations, but also more likely to be zones of enhanced acoustic backscatter and Chl-a fluorescence than regions flanking the fronts. MVBS and Chl-a gradients were significantly correlated with gradients in other hydrographic variables such as temperature, salinity, and spiciness, and weakly with cross-track current velocity, though density gradients remained the single best predictor of strong MVBS and fluorescence gradients. Large mobile predators foraging in the vicinity of such features could locate habitat with higher zooplankton biomass concentrations up to 85% of the time by traveling up local density gradients (i.e., toward rather than away from denser surface waters). We discuss implications of these results in the context of long-term trends

  13. Health system support for childbirth care in Southern Tanzania: results from a health facility census.

    PubMed

    Hanson, Claudia; Ronsmans, Carine; Penfold, Suzanne; Maokola, Werner; Manzi, Fatuma; Jaribu, Jenny; Mbaruku, Godfrey; Mshinda, Hassan; Tanner, Marcel; Schellenberg, Joanna

    2013-10-30

    Progress towards reaching Millennium Development Goals four (child health) and five (maternal health) is lagging behind, particularly in sub-Saharan Africa, despite increasing efforts to scale up high impact interventions. Increasing the proportion of birth attended by a skilled attendant is a main indicator of progress, but not much is known about the quality of childbirth care delivered by these skilled attendants. With a view to reducing maternal mortality through health systems improvement we describe the care routinely offered in childbirth at dispensaries, health centres and hospitals in five districts in rural Southern Tanzania. We use data from a health facility census assessing 159 facilities in five districts in early 2009. A structural and operational assessment was undertaken based on staff reports using a modular questionnaire assessing staffing, work load, equipment and supplies as well as interventions routinely implemented during childbirth. Health centres and dispensaries attended a median of eight and four deliveries every month respectively. Dispensaries had a median of 2.5 (IQR 2-3) health workers including auxiliary staff instead of the recommended four clinical officer and certified nurses. Only 28% of first-line facilities (dispensaries and health centres) reported offering active management in the third stage of labour (AMTSL). Essential childbirth care comprising eight interventions including AMTSL, infection prevention, partograph use including foetal monitoring and newborn care including early breastfeeding, thermal care at birth and prevention of ophthalmia neonatorum was offered by 5% of dispensaries, 38% of health centres and 50% of hospitals consistently. No first-line facility had provided all signal functions for emergency obstetric complications in the previous six months. Essential interventions for childbirth care are not routinely implemented in first-line facilities or hospitals. Dispensaries have both low staffing and low

  14. [Rapid evaluation of ant diversity in land use systems in southern Bahia, Brazil].

    PubMed

    Braga, Danielle L; Louzada, Júlio N C; Zanetti, Ronald; Delabie, Jacques

    2010-01-01

    We aimed to compare the soil ant diversity in different land use systems from Atlantic Forest area, in Southern Bahia state, Brazil. The ants were sampled in 16 sites: two primary forest sites (un-logged forest); three young secondary forests (<8 years old); three intermediate secondary forests (8-20 years old); three old secondary forests (>20 years old); three Eucalyptus grandis plantations (3-7 years old), and two introduced pastures. Each site was sampled in three sampling points 15 m apart, and distant over 50 m from the site edge. In each sampling point we gathered the litter from a 1 m² and extracted the ants with Winkler extractors during 48h. We found 103 ant species from 29 genera and eight subfamilies. The five richest genera were Pheidole (19 species), Solenopsis (8), Apterostigma (10), Hypoponera (7) e Paratrechina (5). The highest ant richness density was found in the primary forest (7.4 species/sample; S = 37; n = 5); followed by the old secondary forest (5.33 species/sample; S = 48; n = 9); young secondary forest (5.25 species/sample; S = 42, n = 8); eucalyptus plantation (4.22 species/sample; S = 38, n = 9), intermediate secondary forest (3.5 species/sample; S = 35, n = 10, and introduced pasture (2.67 species/sample; S = 16, n = 6). The ecosystems with higher structural complexity showed the highest ant richness density by sample. Therefore, in the Atlantic Forest region, the eucalyptus plantation is a better alternative of land use to conserve the ant biodiversity than pastures, and quite similar to native secondary forests in ant community characteristics.

  15. Data and Visualizations in the Southern California Earthquake Center's Fault Information System

    NASA Astrophysics Data System (ADS)

    Perry, S.

    2003-12-01

    The Southern California Earthquake Center's Fault Information System (FIS) provides a single point of access to fault-related data and models from multiple databases and datasets. The FIS is built of computer code, metadata and Web interfaces based on Web services technology, which enables queries and data interchange irrespective of computer software or platform. Currently we have working prototypes of programmatic and browser-based access. The first generation FIS may be searched and downloaded live, by automated processes, as well as interactively, by humans using a browser. Users get ascii data in plain text or encoded in XML. Via the Earthquake Information Technology (EIT) Interns (Juve and others, this meeting), we are also testing the effectiveness of querying multiple databases using a fault database ontology. For more than a decade, the California Geological Survey (CGS), SCEC, and the U. S. Geological Survey (USGS) have put considerable, shared resources into compiling and assessing published fault data, then providing the data on the Web. Several databases now exist, with different formats, datasets, purposes, and users, in various stages of completion. When fault databases were first envisioned, the full power of today's internet was not yet recognized, and the databases became the Web equivalents of review papers, where one could read an overview summation of a fault, then copy and paste pertinent data. Today, numerous researchers also require rapid queries and downloads of data. Consequently, the first components of the FIS are MySQL databases that deliver numeric values from earlier, text-based databases. Another essential service provided by the FIS is visualizations of fault representations such as those in SCEC's Community Fault Model. The long term goal is to provide a standardized, open-source, platform-independent visualization technique. Currently, the FIS makes available fault model viewing software for users with access to Matlab or Java3D

  16. Occurrence of aryl hydrocarbon receptor agonists and genotoxic compounds in the river systems in Southern Taiwan.

    PubMed

    Chou, Pei-Hsin; Liu, Tong-Cun; Ko, Fung-Chi; Liao, Mong-Wei; Yeh, Hsiao-Mei; Yang, Tse-Han; Wu, Chun-Ting; Chen, Chien-Hsun; Tsai, Tsung-Ya

    2014-07-01

    Water and sediment samples from river systems located in Southern Taiwan were investigated for the presence of aryl hydrocarbon receptor (AhR) agonists and genotoxicants by a combination of recombinant cell assays and gas chromatography-mass spectrometry analysis. AhR agonist activity and genotoxic response were frequently detected in samples collected during different seasons. In particular, dry-season water and sediment samples from Erren River showed strong AhR agonist activity (201-1423 ng L(-1) and 1374-5631 ng g(-1) β-naphthoflavone equivalents) and high genotoxic potential. Although no significant correlation was found between AhR agonist activity and genotoxicity, potential genotoxicants in sample extracts were suggested to be causative agents for yeast growth inhibition in the AhR-responsive reporter gene assay. After high performance liquid chromatography fractionation, AhR agonist candidates were detected in several fractions of Erren River water and sediment extracts, while possible genotoxicants were only found in water extracts. In addition, polycyclic aromatic hydrocarbons, the typical contaminants showing high AhR binding affinity, were only minor contributors to the AhR agonist activity detected in Erren River sediment extracts. Our findings displayed the usefulness of bioassays in evaluating the extent of environmental contamination, which may be helpful in reducing the chances of false-negative results obtained from chemical analysis of conventional contaminants. Further research will be undertaken to identify major candidates for xenobiotic AhR agonists and genotoxicants to better protect the aquatic environments in Taiwan.

  17. The southern Caribbean upwelling system: Sea surface temperature, wind forcing and chlorophyll concentration patterns

    NASA Astrophysics Data System (ADS)

    Rueda-Roa, Digna T.; Muller-Karger, Frank E.

    2013-08-01

    Sixteen years of sea surface temperature (SST, 1994-2009) were used to characterize the southern Caribbean upwelling system. This system extends from 61-75.5°W and 10-12.5°N, with 21 upwelling foci clustered in seven groups differentiated by their SST cycles. Two of those groups had the strongest coastal upwelling: the ‘eastern area’ (63-65°W) and the ‘western area’ (70-73°W). The literature reports that the eastern and western upwelling areas hold 78% and 18% of the small pelagic biomass within the upwelling system, respectively. We looked into variations of the upwelling dynamics in those areas using seasonal cycles of satellite SST, chlorophyll-a (Chl) and sea-wind, as well as climatological hydrographic data from the World Ocean Atlas. Comparing their annual averages, the eastern area featured the lowest SST (25.24 °C) and the highest Chl (1.65 mg m-3); it has moderate wind intensity (6.12 m s-1) and shallower 22 °C isotherm (85 m). The western area had stronger winds (8.23 m s-1) but deeper 22 °C isotherm (115 m), slightly higher SST (25.53 °C) and moderate Chl (1.15 mg m-3). The upwelling in the eastern area was more prolonged than in the western area (SST <26 °C during 8.5 and 6.9 months, respectively). According to the ‘optimal environmental window’ theory, small clupeoid recruitment is a dome-shaped function of the upwelling intensity, turbulence and SST, with an optimum wind speed around 5-6 m s-1. The eastern upwelling area wind speed is close to this optimum value. The western upwelling area shows much higher wind speed that causes high level of turbulence and strong offshore transport that could hinder small pelagics recruitment in that area.

  18. DDS as middleware of the Southern African Large Telescope control system

    NASA Astrophysics Data System (ADS)

    Maartens, Deneys S.; Brink, Janus D.

    2016-07-01

    The Southern African Large Telescope (SALT) software control system1 is realised as a distributed control system, implemented predominantly in National Instruments' LabVIEW. The telescope control subsystems communicate using cyclic, state-based messages. Currently, transmitting a message is accomplished by performing an HTTP PUT request to a WebDAV directory on a centralised Apache web server, while receiving is based on polling the web server for new messages. While the method works, it presents a number of drawbacks; a scalable distributed communication solution with minimal overhead is a better fit for control systems. This paper describes our exploration of the Data Distribution Service (DDS). DDS is a formal standard specification, defined by the Object Management Group (OMG), that presents a data-centric publish-subscribe model for distributed application communication and integration. It provides an infrastructure for platform- independent many-to-many communication. A number of vendors provide implementations of the DDS standard; RTI, in particular, provides a DDS toolkit for LabVIEW. This toolkit has been evaluated against the needs of SALT, and a few deficiencies have been identified. We have developed our own implementation that interfaces LabVIEW to DDS in order to address our specific needs. Our LabVIEW DDS interface implementation is built against the RTI DDS Core component, provided by RTI under their Open Community Source licence. Our needs dictate that the interface implementation be platform independent. Since we have access to the RTI DDS Core source code, we are able to build the RTI DDS libraries for any of the platforms on which we require support. The communications functionality is based on UDP multicasting. Multicasting is an efficient communications mechanism with low overheads which avoids duplicated point-to-point transmission of data on a network where there are multiple recipients of the data. In the paper we present a performance

  19. Trophic functioning of the St. Lucia estuarine lake during a drought phase assessed using stable isotopes

    NASA Astrophysics Data System (ADS)

    Govender, Natasha; Smit, Albertus J.; Perissinotto, Renzo

    2011-06-01

    The St. Lucia Estuary is Africa's largest estuarine system and is currently experiencing the stress of prolonged freshwater deprivation, manifested by extremely low water levels and hypersalinity. These unprecedented conditions have raised questions regarding the trophic functioning of the ecosystem. Despite the substantial amount of research previously undertaken within this system, no studies of food web structure and function have yet been documented. This study therefore aimed to examine the food web structure of the St. Lucia estuary system through the use of carbon and nitrogen stable isotope analysis. Analysis of carbon isotope ratios indicates that benthic carbon sources are most utilised at sites with low water levels and generally higher salinity (Catalina Bay, Charter's Creek). Conversely, the estuarine region of the mouth and Narrows, with its elevated water levels and lower salinity, still sustains a viable pelagic food web. Analysis of δ15N ratios indicates that the number of trophic transfers (food chain length) might be related to water levels. Overall, the study provides a greater understanding of the ecological processes of this complex estuarine lake, which may allow for future comparisons of trophic functioning under drought and normal/wet conditions to be made.

  20. Estuarine Export of Dissolved Organic Carbon to the Mid-Atlantic Bight

    NASA Astrophysics Data System (ADS)

    Signorini, S. R.; Mannino, A.; Friedrichs, M. A.; Wilkin, J.; Tabatabai, A.

    2016-02-01

    Estuaries play an important role in transforming riverine nutrients and carbon before they are exported to the adjacent continental shelf. Land-estuarine-ocean biogeochemical modeling systems, evaluated with in situ and satellite data, are invaluable tools to quantify riverine nitrogen and carbon inputs, within-estuary nitrogen/carbon transformation processes and the ultimate export of nitrogen and carbon to the coastal ocean. In this study, we developed satellite algorithms to retrieve estuarine dissolved organic carbon (DOC) concentrations, and combined these surface DOC estimates with output from physical circulation models based on the Regional Ocean Modeling System (ROMS) to quantify coastal DOC fluxes. This study specifically focuses on the export of DOC from two major estuaries, Chesapeake Bay and Delaware Bay, to the U.S. Middle Atlantic Bight (MAB) using newly developed higher resolution models. DOC profiles required to compute the tracer fluxes at the mouths of the estuaries were derived using a feed forward neural networks model trained with in situ data (salinity, temperature, and DOC).The seasonal and interannual variability of estuarine DOC export are analyzed based on multi-year model runs for Delaware Bay and Chesapeake Bay, combined with surface DOC concentrations derived from the satellite retrievals. Fluxes derived from coupled biogeochemical-circulation modeling systems are compared with these off-line model-satellite tracer fluxes. Results from this study will be used to improve the assessment of the total carbon budget for the MAB.

  1. Pronounced changes in carbonate system and temperature history of the Southern California margin from LGM to present

    NASA Astrophysics Data System (ADS)

    Quintana Krupinski, N. B.; Pak, D. K.; Hill, T. M.; Paytan, A.

    2012-12-01

    Millennial-scale records of the marine carbonate system and its natural variability provide long-term perspective on anthropogenically-induced ocean acidification, and provide a basis for determining whether there is a critical threshold at which organisms may be negatively affected by changing carbonate saturation and pH. The state, stability and natural variability of pre-anthropogenic marine carbonate systems can be reconstructed from carbonate system proxies in foraminiferal calcite. Using newly calibrated proxies, we quantify the long-term history and variability of the surface water carbonate system in the Southern California Borderland, a coastal region that experiences substantial pH fluctuations today. Our reconstruction of temperature also allows comparison with other nearby Southern California temperature reconstructions. We present trace metal (B/Ca, U/Ca and Mg/Ca), stable isotope (δ18O , δ13C ) and shell weight results from the planktonic foraminifera G. bulloides and N. incompta (N. pachyderma (d)) from Santa Monica Basin (SMB; ODP 1015) to reconstruct the past surface ocean carbonate system and temperature for the past ~32ka. We observe a gradual decrease in B/Ca in the thermocline-dwelling N. incompta from 20ka to ~12ka, likely reflecting the decrease in global ocean pH and [CO32-] during deglaciation. Changes in temperature and ocean carbonate chemistry can be observed during the Younger Dryas and Bolling-Allerod in trace metal, stable isotope and shell weight records. Compared with other nearby Southern California ODP sites, temperatures from Mg/Ca during deglaciation in SMB are cooler by ~1-3 degrees, and show a larger temperature difference between G. bulloides and N. incompta during glacial time than other regional sites. These results strengthen evidence that the southern California Borderland shows a strong atmospheric teleconnection to North Atlantic climate changes, and also provide the opportunity to assess what aspects of southern

  2. Statistical comparison and correlation of zinc and lead in estuarine sediments along the western coast of Mauritius.

    PubMed

    Ramessur, Roshan T

    2004-10-01

    Cr, Zn and Pb were quantified using atomic absorption spectrometry (AAS) from urban and rural estuarine sediments collected along the western coast of Mauritius during the period July 2002-January 2003. The mean concentration of Cr (225.4 mg kg(-1)), Zn (107.0 mg kg(-1)) and Pb (27.0 mg kg(-1)) in sediments along the six estuaries can be considered below those from contaminated estuarine sediments. Zn and Pb were significantly higher in urban sediments downstream St. Louis River compared to a rural estuary at Tamarin at 5% significance level. Zn was also significantly lower in Tamarin compared to Petite Riviere Noire estuary. Cr was however not significantly different in sediments from the six estuaries and could be considered of basaltic origin and were correlated to neither lead nor zinc. The concentration of Zn and Pb were greatest in the more urbanised upper and lower reaches of the St. Louis estuary during the period of study and were also significantly positively correlated in the estuarine sediments indicating that the cycling of Pb and Zn were linked indicating a common source for Pb and Zn. The potential sources of Pb and Zn in the urban estuarine sediments were considered to arise from road runoff causing significant quantities to be trapped. At present, compared to contaminant levels found in the UK and elsewhere, Mauritius still looks relatively uncontaminated but there is growing concern about heavy metal contamination in urban estuaries. There is therefore a need for long-term studies in estuarine management to involve integrated strategies in which water-sediment interactions in estuaries need to be considered and international standards for sediment quality developed. Such studies undertaken in the future would further the understanding of the biogeochemical processes of estuarine systems in Mauritius which could then be used in environmental development schemes and effective coastal zone management.

  3. Middle Jurassic incised valley fill (eolian/estuarine) and nearshore marine petroleum reservoirs, Powder River basin

    SciTech Connect

    Ahlbrandt, T.S.; Fox, J.E.

    1997-07-01

    Paleovalleys incised into the Triassic Spearfish Formation (Chugwater equivalent) are filled with a vertical sequence of eolian, estuarine, and marine sandstones of the Middle Jurassic (Bathonian age) Canyon Springs Sandstone Member of the Sundance Formation. An outcrop exemplifying this is located at Red Canyon in the southern Black Hills, Fall River County, South Dakota. These paleovalleys locally have more than 300 ft of relief and are as much as several miles wide. Because they slope in a westerly direction, and Jurassic seas transgressed into the area from the west there was greater marine-influence and more stratigraphic complexity in the subsurface, to the west, as compared to the Black Hills outcrops. In the subsurface two distinctive reservoir sandstone beds within the Canyon Springs Sandstone Member fill the paleovalleys. These are the eolian lower Canyon Springs unit (LCS) and the estuarine upper Canyon Springs unit (UCS), separated by the marine {open_quotes}Limestone Marker{close_quotes} and estuarine {open_quotes}Brown Shale{close_quotes}. The LCS and UCS contain significant proven hydrocarbon reservoirs in Wyoming (about 500 MMBO in-place in 9 fields, 188 MMBO produced through 1993) and are prospective in western South Dakota, western Nebraska and northern Colorado. Also prospective is the Callovian-age Hulett Sandstone Member which consists of multiple prograding shoreface to foreshore parasequences, as interpreted from the Red Canyon locality. Petrographic, outcrop and subsurface studies demonstrate the viability of both the Canyon Springs Sandstone and Hulett Sandstone members as superior hydrocarbon reservoirs in both stratigraphic and structural traps. Examples of fields with hydrocarbon production from the Canyon Springs in paleovalleys include Lance Creek field (56 MMBO produced) and the more recently discovered Red Bird field (300 MBO produced), both in Niobrara County, Wyoming.

  4. Biotic resistance to invasion along an estuarine gradient

    PubMed Central

    Hovel, Kevin A.

    2010-01-01

    Biotic resistance is the ability of native communities to repel the establishment of invasive species. Predation by native species may confer biotic resistance to communities, but the environmental context under which this form of biotic resistance occurs is not well understood. We evaluated several factors that influence the distribution of invasive Asian mussels (Musculista senhousia) in Mission Bay, a southern California estuary containing an extensive eelgrass (Zostera marina) habitat. Asian mussels exhibit a distinct spatial pattern of invasion, with extremely high densities towards the back of Mission Bay (up to 4,000 m−2) in contrast with near-complete absence at sites towards the front of the bay. We established that recruits arrived at sites where adult mussels were absent and found that dense eelgrass does not appear to preclude Asian mussel growth and survival. Mussel survival and growth were high in predator-exclusion plots throughout the bay, but mussel survival was low in the front of the bay when plots were open to predators. Additional experiments revealed that consumption by spiny lobsters (Panulirus interruptus) and a gastropod (Pteropurpura festiva) likely are the primary factors responsible for resistance to Asian mussel invasion. However, biotic resistance was dependent on location within the estuary (for both species) and also on the availability of a hard substratum (for P. festiva). Our findings indicate that biotic resistance in the form of predation may be conferred by higher order predators, but that the strength of resistance may strongly vary across estuarine gradients and depend on the nature of the locally available habitat. Electronic supplementary material The online version of this article (doi:10.1007/s00442-010-1700-7) contains supplementary material, which is available to authorized users. PMID:20602118

  5. Biotic resistance to invasion along an estuarine gradient.

    PubMed

    Cheng, Brian S; Hovel, Kevin A

    2010-12-01

    Biotic resistance is the ability of native communities to repel the establishment of invasive species. Predation by native species may confer biotic resistance to communities, but the environmental context under which this form of biotic resistance occurs is not well understood. We evaluated several factors that influence the distribution of invasive Asian mussels (Musculista senhousia) in Mission Bay, a southern California estuary containing an extensive eelgrass (Zostera marina) habitat. Asian mussels exhibit a distinct spatial pattern of invasion, with extremely high densities towards the back of Mission Bay (up to 4,000 m(-2)) in contrast with near-complete absence at sites towards the front of the bay. We established that recruits arrived at sites where adult mussels were absent and found that dense eelgrass does not appear to preclude Asian mussel growth and survival. Mussel survival and growth were high in predator-exclusion plots throughout the bay, but mussel survival was low in the front of the bay when plots were open to predators. Additional experiments revealed that consumption by spiny lobsters (Panulirus interruptus) and a gastropod (Pteropurpura festiva) likely are the primary factors responsible for resistance to Asian mussel invasion. However, biotic resistance was dependent on location within the estuary (for both species) and also on the availability of a hard substratum (for P. festiva). Our findings indicate that biotic resistance in the form of predation may be conferred by higher order predators, but that the strength of resistance may strongly vary across estuarine gradients and depend on the nature of the locally available habitat.

  6. Current Dynamics of Estuarine Circulation in the Lateral Boundary Layer

    NASA Astrophysics Data System (ADS)

    Raudsepp, U.

    1998-12-01

    High spatial resolution measurements of current velocity performed by the shipboard mounted Acoustic Doppler Current Profiler (ADCP) in the lateral boundary layer of the southern Gulf of Finland during two 5-day periods are described and analysed with a focus on the dominant dynamics. The measurement site represents a small (15×20 km), relatively deep (up to 100 m) bay opened to large-scale estuarine circulation. The measurement period was characterized by calm winds and a strong seasonal pycnocline (Brunt-Väisälä frequencyN=6-9*10-2 s-1). The quasi-steady velocity field revealed polarization of currents along the shore whereas an intensive baroclinic coastal jet was observed over a cross-shore scale of 1-2 km. The level of vertical separation of the alongshore flow coincided with the pycnocline at the coast, but was shifted below it in the offshore region. The cross-shore flow was considerably weaker and showed a three-layer structure with an opposite phase between the first and second surveys. It is suggested that the observed jet resembles a non-locally forced eastward propagating coastally trapped wave. In the offshore area the alongshore flow field satisfies local geostrophic balance quite well, except in the pycnocline where strong vertical stratification exerts considerable vertical stress. As vertical velocity shear is well correlated with vertical stratification, the horizontal advection prevails over vertical mixing. Horizontal inhomogeneities of density distribution are partly explained by vertical velocities with an estimated magnitude of less than 0·6 mm/s and the spatial pattern following bottom topography.

  7. REGIONAL AND STATE VIEWS OF ESTUARINE CONDITION IN NORTHEASTERN UNITED STATE BASED ON 2001 AND 2001 NATIONAL COASTAL ASSESSMENT DATA

    EPA Science Inventory

    The National Coastal Assessment (NCA) is a probability-based survey that permits assessment of estuarine conditions at national, regional, or large-system scales. Additionally, states may use these data to comply with requirements of the Clean Water Act (CWA), which mandates re...

  8. Comparative evaluation of effects of ozonated and chlorinated thermal discharges on estuarine and freshwater organisms

    SciTech Connect

    Guerra, C.R.; Sugam, R.; Meldrim, J.W.; Holmstrom, E.R.; Balog, G.E.

    1980-08-01

    As a part of a program at PSE and G designed to examine the feasibility of ozonation as an alternative to chlorination for control of biofouling in once-through cooling systems, the biological effects of ozonated and chlorinated thermal discharges were evaluated with estuarine and freshwater organisms. Mortality at salinities between 0.5 to 2.5 ppt with mummichog and white perch indicated greater toxicity for chlorine while the alewife, spottail shiner, rainbow trout and white perch in freshwater were more sensitive to ozone. Behavioral and physograhic results were consistent with those observed in toxicity studies. Initial cough response and avoidance concentrations of mummicog and white perch in estuarine waters were lower when exposed to chlorine than to ozone. In freshwater, blueback herring, alewife, rainbow trout, spottail shiner, banded killifish, and white perch avoided lower concentrations of ozone than chlorine.

  9. Bioconcentration of endosulfan in different body tissues of estuarine organisms under sublethal exposure

    SciTech Connect

    Rajendran, N. ); Venugopalan, V.K. )

    1991-01-01

    The organochlorine pesticide endosulfan is applied in the agricultural fields as liquid in India. Investigations have revealed the occurrence and distribution of endosulfan in both biotic and abiotic components of Vellar estuary. The results from static bioassay studies revealed that fishes were more susceptible to the organochlorine pesticides than mollusks. Though the available information on the uptake of endosulfan by the estuarine organisms are limited to whole body tissues, no attempt has been made to find out the extent of uptake of pesticides by the different body tissues of the estuarine organisms. Hence the present study was planned to determine the bioconcentration of endosulfan in different tissues of fishes Mugil cephalus, Mystus gulio, oyster Crassostrea madrasensis and clam Katelysia opima based on the measured concentration of endosulfan in the experimental medium of the continuous flow through system for a period of 10 d.

  10. The interdisciplinary marine system of the Amundsen Sea, Southern Ocean: Recent advances and the need for sustained observations

    NASA Astrophysics Data System (ADS)

    Meredith, Michael P.; Ducklow, Hugh W.; Schofield, Oscar; Wåhlin, Anna; Newman, Louise; Lee, SangHoon

    2016-01-01

    The Southern Ocean exerts a profound influence on the functioning of the Earth System, in part because its location and unique bathymetric configuration enable direct linkages to the other major ocean basins (Ganachaud and Wunsch, 2000; Lumpkin and Speer, 2007). It is the site of the world's largest current system, the Antarctic Circumpolar Current (ACC), which transfers waters and climatically/ecologically-important tracers between the Atlantic, Indian and Pacific Oceans (Rintoul et al., 2001). In addition to the strong horizontal connectivity, the ACC is also characterized by a vigorous overturning circulation, which upwells warm, nutrient-rich waters from intermediate depth to the surface, where they are modified by interactions with the atmosphere and cryosphere to form new water masses, some of which are lighter and others more dense (Marshall and Speer, 2012). This overturning circulation structures the Southern Ocean both horizontally and vertically, dictates the levels of its communication with the rest of the global ocean, and is a fundamental control on the sequestration of carbon from the atmosphere into the ocean interior (Sallée et al., 2012). In some locations, the upwelled waters can intrude onto the Antarctic shelves, supplying heat and nutrients to the shallower regions. This is believed to be especially effective in west Antarctica, where the southern edge of the ACC moves close to the shelf break (Martinson, 2011; Orsi et al., 1995; Thoma et al., 2008).

  11. Site/Systems Operations, Maintenance and Facilities Management of the Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) Cloud and Radiation Testbed (CART) Site

    SciTech Connect

    Wu, Susan

    2005-08-01

    This contract covered the site/systems operations, maintenance, and facilities management of the DOE Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) Cloud and Radiation Testbed (CART) Site.

  12. Sediment measurement in estuarine and coastal areas

    NASA Technical Reports Server (NTRS)

    Shelley, P. E.

    1976-01-01

    A survey of uses of estuarine and coastal areas is given. Problems associated with these uses are discussed, and data needs for intelligent management of these valuable areas are outlined. Suspended sediment measurements are seen to be one of the greatest needs. To help understand the complexity of the problem, a brief discussion of sediment mechanics is given, including sediment sources, characteristics, and transport. The impact of sediment mechanics on its direct measurement (sampling and analysis) is indicated, along with recommendations for directly obtaining representative data. Indirect measurement of suspended sediment by remote sensors is discussed both theoretically and in the light of some recent experiences. The need for an integrated, multidisciplinary program to solve the problem of quantitatively measuring suspended sediment with remote sensors is stressed, and several important considerations of such a program and benefits to be derived therefrom are briefly addressed.

  13. Numerical noise in ocean and estuarine models

    USGS Publications Warehouse

    Walters, R.; Carey, G.F.

    1984-01-01

    Approximate methods for solving the shallow water equations may lead to solutions exhibiting large fictitious, numerically-induced oscillations. The analysis of the discrete dispersion relation and modal solutions of small wavelengths provides a powerful technique for assessing the sensitivity of alternative numerical schemes to irregular data which may lead to such oscillatory numerical noise. For those schemes where phase speed vanishes at a finite wavenumber or there are multiple roots for wavenumber, oscillation modes can exist which are uncoupled from the dynamics of the problem. The discrete modal analysis approach is used here to identify two classes of spurious oscillation modes associated respectively with the two different asymptotic limits corresponding to estuarine and large scale ocean models. The analysis provides further insight into recent numerical results for models which include large spatial scales and Coriolis acceleration. ?? 1984.

  14. Nitrous oxide production by estuarine epiphyton

    SciTech Connect

    Law, C.S.; Rees, A.P.; Owens, N.J.P. )

    1993-03-01

    Nitrous oxide was produced by denitrifying bacteria in epiphytic communities on the surface of the macroalgae Enteromorpha sp. and Fucus sp. during spring-summer in the Tamar estuary, SW England. Denitrification and N[sub 2]O production exhibited diel variability, in response to photosynthetic oxygen production. Temporal variability in the rate of N[sub 2]O production was observed in Enteromorpha incubations; the variability reflected the heterogeneity of the epiphytic microbial population density. N[sub 2]O production by epiphyton associated with Enteromorpha would enhance the sediment N[sub 2]O flux by 150-500% at maximal algal densities and so increase estuarine N[sub 2]O flux to the atmosphere. 20 refs., 6 figs.

  15. Insights on the Optical Properties of Estuarine DOM – Hydrological and Biological Influences

    PubMed Central

    Santos, Luísa; Pinto, António; Filipe, Olga; Cunha, Ângela; Santos, Eduarda B. H.

    2016-01-01

    Dissolved organic matter (DOM) in estuaries derives from a diverse array of both allochthonous and autochthonous sources. In the estuarine system Ria de Aveiro (Portugal), the seasonality and the sources of the fraction of DOM that absorbs light (CDOM) were inferred using its optical and fluorescence properties. CDOM parameters known to be affected by aromaticity and molecular weight were correlated with physical, chemical and meteorological parameters. Two sites, representative of the marine and brackish water zones of the estuary, and with different hydrological characteristics, were regularly surveyed along two years, in order to determine the major influences on CDOM properties. Terrestrial-derived compounds are the predominant source of CDOM in the estuary during almost all the year and the two estuarine zones presented distinct amounts, as well as absorbance and fluorescence characteristics. Freshwater inputs have major influence on the dynamics of CDOM in the estuary, in particular at the brackish water zone, where accounted for approximately 60% of CDOM variability. With a lower magnitude, the biological productivity also impacted the optical properties of CDOM, explaining about 15% of its variability. Therefore, climate changes related to seasonal and inter-annual variations of the precipitation amounts might impact the dynamics of CDOM significantly, influencing its photochemistry and the microbiological activities in estuarine systems. PMID:27195702

  16. Exploring School Effects across Southern and Eastern African School Systems and in Tanzania

    ERIC Educational Resources Information Center

    Yu, Guoxing; Thomas, Sally M.

    2008-01-01

    The Southern and Eastern Africa Consortium for Monitoring Educational Quality (SACMEQ) II data are analysed, using multilevel modelling techniques, to explore the key issues underlying the development of school effectiveness models. Differences between schools in Grade 6 pupils' reading and mathematics achievements are examined and the percentage…

  17. Evaluation of commercial cotton harvesting systems in the southern high plains

    USDA-ARS?s Scientific Manuscript database

    Cotton production practices have changed in the Southern High Plains of the US over the last decade resulting in increased yeilds and improved fiber quality. Moreover, the majority of US cotton now competes in a global fiber market that demands higher quality fiber for ring spun yarn than the former...

  18. Wetlands systems in southern Thailand: The essential resources for sustainable regional development

    Treesearch

    Rotchanatch Darnsawasdi; Prassert Chitpong

    2000-01-01

    Parts of Southern Thailand are inundated by water for months annually resulting in various wetlands including, among others, Tapi River Basin, Pak Panang River Basin, Songkhla Lake Basin, Pangnga Bay, Pattani River Basin, and Narathiwas Peat Swamp. Most wetlands perform functions such as flood retention, water filtration, bird and wildlife habitat,and tree growth....

  19. Pastoral mobility and policy recommendations for livestock herding in the Borana pastoral system in southern Ethiopia

    USDA-ARS?s Scientific Manuscript database

    Livelihoods of pastoralists in the Borana Zone of southern Ethiopia have become increasingly vulnerable as a result of stressors like accelerating population growth, shrinking resource availability, sedentarization, and increased frequency and severity of drought. A research team from the USDA Agric...

  20. Formation of albitite-hosted uranium within IOCG systems: the Southern Breccia, Great Bear magmatic zone, Northwest Territories, Canada

    NASA Astrophysics Data System (ADS)

    Montreuil, Jean-François; Corriveau, Louise; Potter, Eric G.

    2015-03-01

    Uranium and polymetallic U mineralization hosted within brecciated albitites occurs one kilometer south of the magnetite-rich Au-Co-Bi-Cu NICO deposit in the southern Great Bear magmatic zone (GBMZ), Canada. Concentrations up to 1 wt% U are distributed throughout a 3 by 0.5 km albitization corridor defined as the Southern Breccia zone. Two distinct U mineralization events are observed. Primary uraninite precipitated with or without pyrite-chalcopyrite ± molybdenite within magnetite-ilmenite-biotite-K-feldspar-altered breccias during high-temperature potassic-iron alteration. Subsequently, pitchblende precipitated in earthy hematite-specular hematite-chlorite veins associated with a low-temperature iron-magnesium alteration. The uraninite-bearing mineralization postdates sodic (albite) and more localized high-temperature potassic-iron (biotite-magnetite ± K-feldspar) alteration yet predates potassic (K-feldspar), boron (tourmaline) and potassic-iron-magnesium (hematite ± K-feldspar ± chlorite) alteration. The Southern Breccia zone shares attributes of the Valhalla (Australia) and Lagoa Real (Brazil) albitite-hosted U deposits but contains greater iron oxide contents and lower contents of riebeckite and carbonates. Potassium, Ni, and Th are also enriched whereas Zr and Sr are depleted with respect to the aforementioned albitite-hosted U deposits. Field relationships, geochemical signatures and available U-Pb dates on pre-, syn- and post-mineralization intrusions place the development of the Southern Breccia and the NICO deposit as part of a single iron oxide alkali-altered (IOAA) system. In addition, this case example illustrates that albitite-hosted U deposits can form in albitization zones that predate base and precious metal ore zones in a single IOAA system and become traps for U and multiple metals once the tectonic regime favors fluid mixing and oxidation-reduction reactions.

  1. Accumulation and trace-metal variability of estuarine sediments, St. Bernard delta geomorphic region, Louisiana

    SciTech Connect

    Landrum, K.E.

    1995-10-01

    Prior to government regulation, little monitoring of metal discharges into the canals, bayous, and rivers that drain estuarine systems occured. Discharges of trace-metals by industries and municipalities into surface water bodies are presently regulated through the use of Federal and State mandated permit programs. Resource management of economically important estuarine systems has fostered increasing concern over the accumulation of trace-metal pollutants in water, sediments, and biota from these dynamic areas. The acid-leachable concentrations of fourteen trace-metals were determined for 125 bottom sediment samples and 50 core interval samples by plasma emission analysis. Bottom sediments of the St. Bernard estuarom complex consist predominantly of silty clays and clayey silts derived from the erosion of the St. Bernard lobe of the Mississippi River delta and sediments associated with historic crevasses along the Mississippi River. Within the 2 cm core intervals, trace-metal concentrations of Ba, Cr, Cd, Pb, and Zn increased by 10% to 18% in sediments accumulated within the last 75 years. Trace-metal concentrations from sediments for the study area tend to have greater mean concentrations than Florida estuarine sediments, basinwide and Gulf Coast trace-metal comparisons, sediment geochronology. Rates varied from 0.12 to 0.21 cm/yr. Within the 2 cm core intervals, trace-metal concentrations of Ba, Cr, Cd, Pb, and Zn increased by 10% to 18% in sediments accumulated within the last 75 years. Natural trace-metal variability was examined through the use of an aluminum normalization model based on Florida and Louisiana estuarine sediments, basinwide and Gulf Coast trace-metal comparisons, sediment geochronology, and grain-size corrected data. Elevated concentrations of As, Ba, Cd, Pb, V and Zn were noted from sediments associated with oil and gas drilling and production, sandblasting and shipbuilding, dredging, and stormwater, municipal, and industrial discharges.

  2. Contribution of primary producers to mercury trophic transfer in estuarine ecosystems: possible effects of eutrophication.

    PubMed

    Coelho, J P; Pereira, M E; Duarte, A C; Pardal, M A

    2009-08-01

    There is an ongoing eutrophication process in the Ria de Aveiro coastal lagoon (Portugal), with progressive replacement of rooted primary producers for macroalgae. Taking advantage of a well-defined environmental contamination gradient, we studied mercury accumulation and distribution in the aboveground and the belowground biomass of several salt marsh plants, including the seagrass species Zostera noltii and the dominant green macroalgal species Enteromorpha sp. The results of these experiments were then placed into the context of the estuarine mercury cycle and transport from the contaminated area. All salt marsh plants accumulated mercury in the root system, with Halimione portulacoides showing the highest levels, with up to 1.3 mg kg(-1) observed in the most contaminated area. Belowground/aboveground ratios were generally below 0.4, suggesting that salt marsh plants are efficient immobilizers and retainers of mercury agents. Moreover, due to their sediment accretion capacities, salt marsh plants seem to play an important role in the sequestration of mercury in estuarine sediments. Seagrasses, on the other hand, accumulated considerable amounts of mercury in the aboveground biomass with belowground/aboveground ratios reaching as high as 1.4. These results may be due to their different routes of uptake (roots and foliar uptake) which suggests that seagrass meadows can be an important agent in the export of mercury from contaminated areas, considering the high aboveground biomass replacement rates. Rooted macrophytes accumulate less mercury in their aboveground biomass than macroalgae. The change of primary producer dominance due to eutrophication can originate a 4- to 5-fold increase in primary producer associated mercury. This mercury would be available for export, making it bioavailable to estuarine food webs, which stresses the need to reverse the current eutrophic status of estuarine systems.

  3. Cordon Caulle: an active volcanic-geothermal extensional system of Southern Andes of Chile

    NASA Astrophysics Data System (ADS)

    Sepulveda, F.

    2013-05-01

    Cordon Caulle (CC; 40.5° S) is an active volcanic-geothermal system of the Southern Volcanic Zone (SVZ; 37°-44°S). Morphologically, the CC system is a 6 km x 13 km volcanic plateau bordered by NW-trending structures, limited by Puyehue Volcano to the SE and by Caldera Nevada Caldera to the NW. While the SVZ is dominantly basaltic, CC is unique in that it has produced a wide compositional spectrum from basalt to rhyolite. The most recent volcanic activity of Puyehue-CC (last 70 ky) is dominantly silicic, including two historic fissure eruptions (1921-1922; 1960) and a recent central eruption from Puyehue Volcano (2011). Abnormally silicic volcanism was formerly attributed to a localized compression and long-term magma residence and differentiation, resulting from the NW orientation of underlying CC structures with respect to a NE-oriented σ1 (linked to regional strike-slip stress state). However, later studies, including examination of morpho-tectonic features; detailed structural analysis of the 1960 eruption (triggered by Mw 9.5 1960 Chilean Earthquake); InSAR deformation and gravity surveys, point to both historic and long-term extension at CC with σhmax oriented NNW to NW. The pre-2011 (i.e. Puyehue Volcano eruption) geothermal features of CC included boiling hot springs and geysers (Caldera Nevada) and fumaroles (CC and Puyehue Volcano). Both water and gas chemistry surveys were undertaken to assess the source fluid composition and equilibrium temperature. The combination of water and gas geothermometers led to a conceptual model of a stratified geothermal reservoir, with shallow, low-chloride, steam-heated aquifers equilibrated at temperatures between 150°-180°C, overlying a deeper, possibly dominated reservoir with temperatures in excess of 280°C. Gas chemistry also produced the highest He ratios of the SVZ, in agreement with a relatively pure, undiluted magmatic signature and heat source fueling the geothermal system. Other indicators such as N2/Ar

  4. Effects of climate change on suitable rice cropping areas, cropping systems and crop water requirements in southern China

    DOE PAGES

    Ye, Qing; Yang, Xiaoguang; Dai, Shuwei; ...

    2015-06-05

    Here, we discuss that rice is one of the main crops grown in southern China. Global climate change has significantly altered the local water availability and temperature regime for rice production. In this study, we explored the influence of climate change on suitable rice cropping areas, rice cropping systems and crop water requirements (CWRs) during the growing season for historical (from 1951 to 2010) and future (from 2011 to 2100) time periods. The results indicated that the land areas suitable for rice cropping systems shifted northward and westward from 1951 to 2100 but with different