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Sample records for river estuary northeastern

  1. SEASONAL VARIATIONS IN RIVER DISCHARGE AND NUTRIENT EXPORT TO A NORTHEASTERN PACIFIC ESTUARY

    EPA Science Inventory

    Seasonal variations in dissolved nitrogen and silica loadings were related to seasonal variability in river discharge. Dissolved nutrient concentrations measured weekly at three stations in the Yaquina River, Oregon from 1999 through 2001, and then monthly in 2002 were used as th...

  2. Folk classification of the crabs and swimming crabs (Crustacea – Brachyura) of the Mamanguape river estuary, Northeastern – Brazil

    PubMed Central

    Ferreira, Emmanoela N; da S Mourão, José; Rocha, Pollyana D; Nascimento, Douglas M; da S Q Bezerra, Dandara Monalisa Mariz

    2009-01-01

    Background Folk taxonomy is a sub-area of ethnobiology that study the way of how traditional communities classify, identify and name their natural resources. The work present was undertaken in two traditional communities (Barra de Mamanguape and Tramataia). The objective of this study was investigate the ethnobiological classification of the local crabs and swimming crabs used by the crustaceous gatherers of the Mamanguape River Estuary (MRE), Paraíba State, Brazil. Methods The methodology used here involved a combination of qualitative methods (open interviews, semi-structured interviews, direct observations, guided tours, surveys, and interviews in synchronic and diachronic situations that crossed-checked and repeated identifications) and quantitative methods (Venn diagram). A total of 32 men and women were interviewed in the two communities. Specimens of the local crustaceans were collected and identified by the harvesters themselves, subsequently fixed in formalin, conserved in 70% ethyl alcohol, identified using appropriate specialized literature, and then deposited in the laboratory of the Zoology Department of the University State of Paraiba. Results The crustaceous gatherers we studied were observed to group crustaceans according to their similarities and differences, producing a hierarchical classification system containing four levels of decreasing taxonomic order: unique beginner, life-form, generic, and specific. A sequential and/or semantic system classification system that is used to classify the ontogeny of the female swimming crab was also identified. Of the nine folk generics identified, 44.5% were monotypic. 55.5% were polytypic and were subdivided into 15 folk specifics. An identification key was elaborated with the data obtained about the folk polytypics generics. Conclusion The detailed knowledge concerning the crabs and swimming crabs revealed by the MRE crustaceous gatherers demonstrates that these people detain a vast knowledge concerning

  3. Landscape Thresholds and the Condition of Northeastern Estuaries

    EPA Science Inventory

    Anthropogenic impacts to northeastern estuaries have been well documented and many researchers have quantified the associations between broad scale human land uses in contributing landscapes and impacted estuarine condition. However, associations alone are not adequate for ident...

  4. Estuaries of the northeastern United States: Habitat and land use signatures

    USGS Publications Warehouse

    Roman, C.T.; Jaworski, N.; Short, F.T.; Findlay, S.; Warren, R.S.

    2000-01-01

    Geographic signatures are physical, chemical, biotic, and human-induced characteristics or processes that help define similar or unique features of estuaries along latitudinal or geographic gradients. Geomorphologically, estuaries of the northeastern U.S., from the Hudson River estuary and northward along the Gulf of Maine shoreline, are highly diverse because of a complex bedrock geology and glacial history. Back-barrier estuaries and lagoons occur within the northeast region, but the dominant type is the drowned-river valley, often with rocky shores. Tidal range and mean depth of northeast estuaries are generally greater when compared to estuaries of the more southern U.S. Atlantic coast and Gulf of Mexico. Because of small estuarine drainage basins, low riverine flows, a bedrock substrate, and dense forest cover, sediment loads in northeast estuaries are generally quite low and water clarity is high. Tidal marshes, seagrass meadows, intertidal mudflats, and rocky shores represent major habitat types that fringe northeast estuaries, supporting commercially-important fauna, forage nekton and benthos, and coastal bird communities, while also serving as links between deeper estuarine waters and habitats through detritus-based pathways. Regarding land use and water quality trends, portions of the northeast have a history of over a century of intense urbanization as reflected in increased total nitrogen and total phosphorus loadings to estuaries, with wastewater treatment facilities and atmospheric deposition being major sources. Agricultural inputs are relatively minor throughout the northeast, with relative importance increasing for coastal plain estuaries. Identifying geographic signatures provides an objective means for comparing the structure function, and processes of estuaries along latitudinal gradients.

  5. SUSCEPTIBILITY OF A NORTHEASTERN GULF OF MEXICO ESTUARY TO HYPOXIA

    EPA Science Inventory

    Bottom water hypoxia is a common adverse consequence of nutrient enrichment in estuaries and coastal waters. To protect against hypoxia, it is helpful to know which waters are most susceptible to hypoxia. Hypoxia has been observed regularly in Pensacola Bay, a northeastern Gulf o...

  6. Carbon dioxide emissions from estuaries of northern and northeastern Brazil

    PubMed Central

    Noriega, Carlos; Araujo, Moacyr

    2014-01-01

    The carbon dioxide flux through the air–water interface of coastal estuarine systems must be quantified to understand the regional balance of carbon and its transport through adjacent coastal regions. We estimated and calculated the emissions of carbon dioxide (FCO2) and the partial pressure of CO2 (pCO2) values in 28 estuarine environments at a variety of spatial scales in the northern and northeastern regions of Brazil. The results showed a mean FCO2 (water to air) of 55 ± 45 mmol·m−2·d−1. Additionally, a negative correlation between dissolved oxygen saturation and pCO2 was observed, indicating a control by biological processes and especially by organic matter degradation. This leads to increased dissolved CO2 concentration in estuarine waters which results in a pCO2 that reached 8,638 μatm. Our study suggests that northern and northeastern Brazilian estuaries act as sources of atmospheric CO2. The range of pCO2 observed were similar to those found in inner estuaries in other places around the world, with the exception of a few semi-arid estuaries (Köppen climate classification – BSh) in which record low levels of pCO2 have been detected. PMID:25145418

  7. EFFECTS OF EROSION AND MACROALGAE ON INTERTIDAL EELGRASS (ZOSTERA MARINA) IN A NORTHEASTERN PACIFIC ESTUARY (USA)

    EPA Science Inventory

    Eelgrass (Zostera marina) in open-coast northeastern Pacific estuaries is primarily intertidal, yet little research has been done on the natural factors controlling its upper intertidal growth limits. This two-year study in the Yaquina Estuary (Newport, Oregon, USA) evaluated the...

  8. LOWER COLUMBIA RIVER ESTUARY PROGRAM COMPREHENSIVE CONSERVATION AND MANAGEMENT PLAN

    EPA Science Inventory

    An estuary is the area where the fresh water of a river meets the salt water of an ocean. In the Columbia River system, this occurs in the lower 46 river miles. In an estuary, the river has a direct, natural connection with the open sea. This transition from fresh to salt water c...

  9. Historical changes in the Columbia River Estuary

    NASA Astrophysics Data System (ADS)

    Sherwood, Christopher R.; Jay, David A.; Bradford Harvey, R.; Hamilton, Peter; Simenstad, Charles A.

    Historical changes in the hydrology, sedimentology, and physical oceanography of the Columbia River Estuary have been evaluated with a combination of statistical, cartographic, and numerical-modelling techniques. Comparison of data digitized from US Coast and Geodetic Survey bathymetric surveys conducted in the periods 1867-1875, 1926-1937, and 1949-1958 reveals that large changes in the morphology of the estuary have been caused by navigational improvements (jetties, dredged channels, and pile dikes) and by the diking and filling of much of the wetland area. Lesser changes are attributable to natural shoaling and erosion. There has been roughly a 15% decrease in tidal prism and a net accumulation of about 68 × 10 6m 3 of sediment in the estuary. Large volumes of sediment have been eroded from the entrance region and deposited on the continental shelf and in the balance of the estuary, contributing to formation of new land. The bathymetric data indicate that, ignoring erosion at the entrance, 370 to 485 × 10 6m 3 of sediment has been deposited in the estuary since 1868 at an average rate of about 0.5 cm y -1, roughly 5 times the rate at which sea level has fallen locally since the turn of the century. Riverflow data indicate that the seasonal flow cycle of the Columbia River has been significantly altered by regulation and diversion of water for irrigation. The greatest changes have occurred in the last thirty years. Flow variability over periods greater than a month has been significantly damped and the net discharge has been slightly reduced. These changes in riverflow are too recent to be reflected in the available in the available bathymetric data. Results from a laterally averaged, multiple-channel, two-dimensional numerical flow model (described in HAMILTON, 1990) suggest that the changes in morphology and riverflow have reduced mixing, increased stratification, altered the response to fortnightly (neap-spring) changes in tidal forcing, and decreased the

  10. Benthic primary production in the Columbia River Estuary. Final report

    SciTech Connect

    McIntire, C.D.; Amspoker, M.C.

    1984-02-01

    The general objective of the research associated with the Benthic Primary Production Work Unit of Columbia River Estuary Development Program was to determine mechanisms that control the production dynamics and species composition of benthic plant assemblages in the Columbia River Estuary. In particular, the work was concerned with effects of selected physical variables on structural and functional attributes of micro- and macro- vegetation, and on the productivity and biomass of benthic autotrophs on the tidal flats of the estuary.

  11. Changes in Belowground Roots, Rhizomes, and Respiration in Coastal Wetlands in Urbanized Northeastern USA Estuaries

    EPA Science Inventory

    Many organic-rich salt marshes in the northeastern USA are disappearing at an alarming rate. In the Jamaica Bay Estuary (NY), marshes are reported to be eroding at approximately 14-16 hectares per year. These losses are due to multiple stressors, including sewage effluent inputs,...

  12. Acoustical Characterization of the Columbia River Estuary

    NASA Astrophysics Data System (ADS)

    Reeder, D. B.

    2014-12-01

    Investigations of near-shore and in-shore environments have, rightly, focused on geological, thermodynamic and hydrodynamic parameters. A complementary acoustical characterization of the estuarine environment provides another layer of information to facilitate a more complete understanding of the physical environment. Relatively few acoustical studies have been carried out in rivers, estuaries or other energetic environments; nearly all acoustical work in such environments has been done at high acoustic frequencies—in the 10's and 100's of kHz. To this end, within the context of a larger hydrodynamic field experiment (RIVET II), a small acoustic field experiment was carried out in the Columbia River Estuary (CRE), the acoustic objective of which was to characterize the acoustic environment in the CRE in terms of ambient noise field statistics and acoustic propagation characteristics at low-to-mid-frequencies. Acoustically, the CRE salt wedge consists of two isospeed layers separated by a thin, three-dimensional high-gradient layer. Results demonstrate that (1) this stratification supports ducting of low-angle acoustic energy in the upper layer and the creation of an acoustic shadow zone in the lower layer; (2) the spatiotemporal dynamics of the salt wedge structure during the very energetic flood and ebb tides induce significant variability in the acoustic environment, as well as significant flow noise across the acoustic transducer; and (3) this flow noise correlates to current velocity and complicates acoustical observations at low frequencies.

  13. Sediment dynamics of the Mzymta river estuary

    NASA Astrophysics Data System (ADS)

    Krylenko, Marina; Isupova, Maria

    2010-05-01

    The Mzymta River dates on the southern slope of the Caucasus Mountains at height 2980 m above sea level. It runs into Black Sea (at Adler, Russia) as uniform channel with width about 170 m, forming a shallow and vast alluvial cone. Length of the Mzymta River is 89 km, the basin area is 885 km2. River alimentation is mixed; water regime is characterized by presence of a spring-and-summer high water and rain high waters. The river sediment runoff is closely connected with features of a water regime of the Mzymta River. The maximum sediment discharge is observed in May and July and occurs due to the high water flow during the flood and high turbidity of waters in this period. The average annual discharge of sediments increases downstream from 4,8 to 11 kg/s. In some years the sediment runoff in a river mouth can reach 730•103 t/year (average turbidity to 420 g/m3) or, on the contrary, decrease to 38•103 t/year (38 g/m3). The greatest value of water turbidity in the Mzymta River was observed in August, 1977 and amount to 11000 g/m3. Average- and small-sand, and clay particles prevail in granulometric composition of the suspended sediments. The river bed is composed by larger material: sand, gravel, pebble and boulder. The river mouth forms a broad alluvial cone blocked by sand alongshore barrier beach. The coast of Black Sea around estuary of the Mzymta River is the accumulative coast generated on steep slope. Beach deposits can leave on the depth excluding return receipt. Several active submarine canyons are situated near Mzymta estuary. Long evolution of these forms carries pulsation character and position of canyons essentially does not vary. According to the aerial mappings for various years, the sizes of pulsations reach 100-120 m. Beach between the Mzymta and Psou rivers are form by Mzymta solid runoff. It confirmed by petrographic structure of the beach deposits. Progressive reduction of the average size of beach deposits and increase of sand part are

  14. 76 FR 8345 - Endangered and Threatened Species; Recovery Plan Module for Columbia River Estuary Salmon and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-14

    ...NMFS announces the adoption of the Columbia River Estuary Endangered Species Act (ESA) Recovery Plan Module for Salmon and Steelhead (Estuary Module). The Estuary Module addresses the estuary recovery needs of all ESA-listed salmon and steelhead in the Columbia River Basin. All Columbia Basin salmon and steelhead ESA recovery plans will incorporate the Estuary Module by...

  15. Columbia River Estuary Ecosystem Classification Ecosystem Complex

    USGS Publications Warehouse

    Cannon, Charles M.; Ramirez, Mary F.; Heatwole, Danelle W.; Burke, Jennifer L.; Simenstad, Charles A.; O'Connor, Jim E.; Marcoe, Keith Marcoe

    2012-01-01

    Estuarine ecosystems are controlled by a variety of processes that operate at multiple spatial and temporal scales. Understanding the hierarchical nature of these processes will aid in prioritization of restoration efforts. This hierarchical Columbia River Estuary Ecosystem Classification (henceforth "Classification") of the Columbia River estuary is a spatial database of the tidally-influenced reaches of the lower Columbia River, the tidally affected parts of its tributaries, and the landforms that make up their floodplains for the 230 kilometers between the Pacific Ocean and Bonneville Dam. This work is a collaborative effort between University of Washington School of Aquatic and Fishery Sciences (henceforth "UW"), U.S. Geological Survey (henceforth "USGS"), and the Lower Columbia Estuary Partnership (henceforth "EP"). Consideration of geomorphologic processes will improve the understanding of controlling physical factors that drive ecosystem evolution along the tidal Columbia River. The Classification is organized around six hierarchical levels, progressing from the coarsest, regional scale to the finest, localized scale: (1) Ecosystem Province; (2) Ecoregion; (3) Hydrogeomorphic Reach; (4) Ecosystem Complex; (5) Geomorphic Catena; and (6) Primary Cover Class. For Levels 4 and 5, we mapped landforms within the Holocene floodplain primarily by visual interpretation of Light Detection and Ranging (LiDAR) topography supplemented with aerial photographs, Natural Resources Conservation Service (NRCS) soils data, and historical maps. Mapped landforms are classified as to their current geomorphic function, the inferred process regime that formed them, and anthropogenic modification. Channels were classified primarily by a set of depth-based rules and geometric relationships. Classification Level 5 floodplain landforms ("geomorphic catenae") were further classified based on multivariate analysis of land-cover within the mapped landform area and attributed as "sub

  16. Columbia River Estuary Ecosystem Classification Geomorphic Catena

    USGS Publications Warehouse

    Cannon, Charles M.; Ramirez, Mary F.; Heatwole, Danelle W.; Burke, Jennifer L.; Simenstad, Charles A.; O'Connor, Jim E.; Marcoe, Keith

    2012-01-01

    Estuarine ecosystems are controlled by a variety of processes that operate at multiple spatial and temporal scales. Understanding the hierarchical nature of these processes will aid in prioritization of restoration efforts. This hierarchical Columbia River Estuary Ecosystem Classification (henceforth "Classification") of the Columbia River estuary is a spatial database of the tidally-influenced reaches of the lower Columbia River, the tidally affected parts of its tributaries, and the landforms that make up their floodplains for the 230 kilometers between the Pacific Ocean and Bonneville Dam. This work is a collaborative effort between University of Washington School of Aquatic and Fishery Sciences (henceforth "UW"), U.S. Geological Survey (henceforth "USGS"), and the Lower Columbia Estuary Partnership (henceforth "EP"). Consideration of geomorphologic processes will improve the understanding of controlling physical factors that drive ecosystem evolution along the tidal Columbia River. The Classification is organized around six hierarchical levels, progressing from the coarsest, regional scale to the finest, localized scale: (1) Ecosystem Province; (2) Ecoregion; (3) Hydrogeomorphic Reach; (4) Ecosystem Complex; (5) Geomorphic Catena; and (6) Primary Cover Class. For Levels 4 and 5, we mapped landforms within the Holocene floodplain primarily by visual interpretation of Light Detection and Ranging (LiDAR) topography supplemented with aerial photographs, Natural Resources Conservation Service (NRCS) soils data, and historical maps. Mapped landforms are classified as to their current geomorphic function, the inferred process regime that formed them, and anthropogenic modification. Channels were classified primarily by a set of depth-based rules and geometric relationships. Classification Level 5 floodplain landforms ("geomorphic catenae") were further classified based on multivariate analysis of land-cover within the mapped landform area and attributed as "sub

  17. Columbia River Estuary Ecosystem Classification Hydrogeomorphic Reach

    USGS Publications Warehouse

    Cannon, Charles M.; Ramirez, Mary F.; Heatwole, Danelle W.; Burke, Jennifer L.; Simenstad, Charles A.; O'Connor, Jim E.; Marcoe, Keith

    2012-01-01

    Estuarine ecosystems are controlled by a variety of processes that operate at multiple spatial and temporal scales. Understanding the hierarchical nature of these processes will aid in prioritization of restoration efforts. This hierarchical Columbia River Estuary Ecosystem Classification (henceforth "Classification") of the Columbia River estuary is a spatial database of the tidally-influenced reaches of the lower Columbia River, the tidally affected parts of its tributaries, and the landforms that make up their floodplains for the 230 kilometers between the Pacific Ocean and Bonneville Dam. This work is a collaborative effort between University of Washington School of Aquatic and Fishery Sciences (henceforth "UW"), U.S. Geological Survey (henceforth "USGS"), and the Lower Columbia Estuary Partnership (henceforth "EP"). Consideration of geomorphologic processes will improve the understanding of controlling physical factors that drive ecosystem evolution along the tidal Columbia River. The Classification is organized around six hierarchical levels, progressing from the coarsest, regional scale to the finest, localized scale: (1) Ecosystem Province; (2) Ecoregion; (3) Hydrogeomorphic Reach; (4) Ecosystem Complex; (5) Geomorphic Catena; and (6) Primary Cover Class. For Levels 4 and 5, we mapped landforms within the Holocene floodplain primarily by visual interpretation of Light Detection and Ranging (LiDAR) topography supplemented with aerial photographs, Natural Resources Conservation Service (NRCS) soils data, and historical maps. Mapped landforms are classified as to their current geomorphic function, the inferred process regime that formed them, and anthropogenic modification. Channels were classified primarily by a set of depth-based rules and geometric relationships. Classification Level 5 floodplain landforms ("geomorphic catenae") were further classified based on multivariate analysis of land-cover within the mapped landform area and attributed as "sub

  18. Upwelling off Yangtze River estuary in summer

    NASA Astrophysics Data System (ADS)

    Lü, Xingang; Qiao, Fangli; Xia, Changshui; Zhu, Jianrong; Yuan, Yeli

    2006-11-01

    The mechanisms of upwelling off the Yangtze River estuary (YRE) and in the adjacent waters in boreal summer are studied using numerical modeling. First, the persistent feature of this phenomenon is confirmed using cruise observations, satellite sea surface temperature (SST), and SST climatologic data. Then, the MASNUM (Marine Science and Numerical Modeling) wave-tide-circulation coupled numerical model is employed to simulate the upwelling patterns. On the basis of the simulation, a set of numerical experiments are designed to explore the main mechanisms inducing the upwelling. The results suggest that tidal mixing plays a predominant role in inducing the upwelling. In offshore waters, strong tidal mixing results in considerable horizontal density gradient across tidal fronts. Upwelling is induced as a branch of the secondary circulation, which is stimulated by the cross-frontal density gradient. Topography also exerts profound influences on upwelling by steering bottom currents to ascend upward and regulating tidal fronts in both location and intensity. Besides the tides and topography, other dynamical factors also alter the strength of upwelling locally. The Yangtze River discharge (YRD) and Taiwan Warm Current (TWC) account partly for the upwelling off the YRE and near Zhoushan Islands, respectively. The influence of wind on upwelling is small. In the coastal waters near Zhoushan Islands, the wind forcing exerts negative influences on upwelling by weakening the encroachment of TWC onto the continental shelf, which may exceed the positive effects of Ekman pumping.

  19. Juvenile salmon usage of the Skeena River estuary.

    PubMed

    Carr-Harris, Charmaine; Gottesfeld, Allen S; Moore, Jonathan W

    2015-01-01

    Migratory salmon transit estuary habitats on their way out to the ocean but this phase of their life cycle is more poorly understood than other phases. The estuaries of large river systems in particular may support many populations and several species of salmon that originate from throughout the upstream river. The Skeena River of British Columbia, Canada, is a large river system with high salmon population- and species-level diversity. The estuary of the Skeena River is under pressure from industrial development, with two gas liquefaction terminals and a potash loading facility in various stages of environmental review processes, providing motivation for understanding the usage of the estuary by juvenile salmon. We conducted a juvenile salmonid sampling program throughout the Skeena River estuary in 2007 and 2013 to investigate the spatial and temporal distribution of different species and populations of salmon. We captured six species of juvenile anadromous salmonids throughout the estuary in both years, and found that areas proposed for development support some of the highest abundances of some species of salmon. Specifically, the highest abundances of sockeye (both years), Chinook in 2007, and coho salmon in 2013 were captured in areas proposed for development. For example, juvenile sockeye salmon were 2-8 times more abundant in the proposed development areas. Genetic stock assignment demonstrated that the Chinook salmon and most of the sockeye salmon that were captured originated from throughout the Skeena watershed, while some sockeye salmon came from the Nass, Stikine, Southeast Alaska, and coastal systems on the northern and central coasts of British Columbia. These fish support extensive commercial, recreational, and First Nations fisheries throughout the Skeena River and beyond. Our results demonstrate that estuary habitats integrate species and population diversity of salmon, and that if proposed development negatively affects the salmon populations that

  20. Juvenile Salmon Usage of the Skeena River Estuary

    PubMed Central

    Carr-Harris, Charmaine; Gottesfeld, Allen S.; Moore, Jonathan W.

    2015-01-01

    Migratory salmon transit estuary habitats on their way out to the ocean but this phase of their life cycle is more poorly understood than other phases. The estuaries of large river systems in particular may support many populations and several species of salmon that originate from throughout the upstream river. The Skeena River of British Columbia, Canada, is a large river system with high salmon population- and species-level diversity. The estuary of the Skeena River is under pressure from industrial development, with two gas liquefaction terminals and a potash loading facility in various stages of environmental review processes, providing motivation for understanding the usage of the estuary by juvenile salmon. We conducted a juvenile salmonid sampling program throughout the Skeena River estuary in 2007 and 2013 to investigate the spatial and temporal distribution of different species and populations of salmon. We captured six species of juvenile anadromous salmonids throughout the estuary in both years, and found that areas proposed for development support some of the highest abundances of some species of salmon. Specifically, the highest abundances of sockeye (both years), Chinook in 2007, and coho salmon in 2013 were captured in areas proposed for development. For example, juvenile sockeye salmon were 2–8 times more abundant in the proposed development areas. Genetic stock assignment demonstrated that the Chinook salmon and most of the sockeye salmon that were captured originated from throughout the Skeena watershed, while some sockeye salmon came from the Nass, Stikine, Southeast Alaska, and coastal systems on the northern and central coasts of British Columbia. These fish support extensive commercial, recreational, and First Nations fisheries throughout the Skeena River and beyond. Our results demonstrate that estuary habitats integrate species and population diversity of salmon, and that if proposed development negatively affects the salmon populations

  1. Trace elements and radionuclides in the Connecticut River and Amazon River estuary

    SciTech Connect

    Dion, E.P.

    1983-01-01

    The Connecticut River, its estuary, and the Amazon River estuary were studied to elucidate some of the processes which control river water chemistry and the flux of elements to the sea. The approach taken was to identify inputs to the Connecticut River and to investigate geochemical processes which modify the dissolved load. The form and quantity of nuclides which are in turn supplied to the estuary are altered by processes unique to that transition zone to the ocean. The Connecticut River estuary was sampled on a seasonal basis to investigate the role of the estuary in controlling the flux of elements to the sea. The knowledge gained from the Connecticut River study was applied to the quantitatively more significant Amazon River estuary. There a variety of samples were analyzed to understand the processes controlling the single greatest flux of elements to the Atlantic Ocean. The results indicate that estimates of the total flux of nuclides to the oceans can best be calculated based on groundwater inputs. Unless significant repositories for nuclides exist in the river-estuarine system, the groundwater flux of dissolved nuclides is that which will eventually be delivered to the ocean despite the reactions which were shown to occur in both rivers and estuaries. 153 references, 63 figures, 28 tables.

  2. Conservation of Thane Creek and Ulhas River Estuary, India.

    PubMed

    Nikam, Vinay S; Kumar, Arun; Lalla, Kamal; Gupta, Kapil

    2009-07-01

    There has been a steady decrease in the area occupied by wetlands in creeks and estuaries adjacent urban areas due to unprecedented urban growth in coastal cities, for example, Thane Creek and Ulhas River Estuary near Mumbai, India. Urban cities serve as centres of employment and attract a large number of migrants from other places. In case of coastal cities, due to inadequate infrastructure, wastewater and solid waste are disposed of into wetlands and estuary. Discharge of sediments and solid waste into the creeks from drains and construction activities has resulted in decreased flow depth in the coastal waters of Thane Creek and Ulhas River Estuary. Various researchers have studied individual elements of Thane Creek and Ulhas River Estuary at micro level. However, a holistic approach for restoration and conservation of the creek and estuary is required. This paper presents the details of an integrated approach incorporating different conservation measures such as sewerage and sewage treatment, urban drainage management, solid waste management, mangrove plantation and dredging. PMID:21117428

  3. Continuous resistivity profiling data from the Corsica River Estuary, Maryland

    USGS Publications Warehouse

    Cross, V.A.; Bratton, J.F.; Worley, C.R.; Crusius, J.; Kroeger, K.D.

    2011-01-01

    Submarine groundwater discharge (SGD) into Maryland's Corsica River Estuary was investigated as part of a larger study to determine its importance in nutrient delivery to the Chesapeake Bay. The Corsica River Estuary represents a coastal lowland setting typical of much of the eastern bay. An interdisciplinary U.S. Geological Survey (USGS) science team conducted field operations in the lower estuary in April and May 2007. Resource managers are concerned about nutrients that are entering the estuary via SGD that may be contributing to eutrophication, harmful algal blooms, and fish kills. Techniques employed in the study included continuous resistivity profiling (CRP), piezometer sampling of submarine groundwater, and collection of a time series of radon tracer activity in surface water. A CRP system measures electrical resistivity of saturated subestuarine sediments to distinguish those bearing fresh water (high resistivity) from those with saline or brackish pore water (low resistivity). This report describes the collection and processing of CRP data and summarizes the results. Based on a grid of 67.6 kilometers of CRP data, low-salinity (high-resistivity) groundwater extended approximately 50-400 meters offshore from estuary shorelines at depths of 5 to >12 meters below the sediment surface, likely beneath a confining unit. A band of low-resistivity sediment detected along the axis of the estuary indicated the presence of a filled paleochannel containing brackish groundwater. The meandering paleochannel likely incised through the confining unit during periods of lower sea level, allowing the low-salinity groundwater plumes originating from land to mix with brackish subestuarine groundwater along the channel margins and to discharge. A better understanding of the spatial variability and geological controls of submarine groundwater flow beneath the Corsica River Estuary could lead to improved models and mitigation strategies for nutrient over-enrichment in the

  4. BIVALVES AS BIOMONITORS IN THE NEUSE RIVER AND ESTUARY

    EPA Science Inventory

    In eastern North Carolina the Neuse River and Neuse Estuary have been heavily impacted by the byproducts of row crop and livestock agriculture, forestry operations, and industry as well as effluent from municipal wastewater treatment plants. Non-point pollutants derived from thes...

  5. Phenology of larval fish in the St. Louis River estuary

    EPA Science Inventory

    Little work has been done on the phenology of fish larvae in Great Lakes coastal wetlands. As part of an aquatic invasive species early detection study, we conducted larval fish surveys in the St. Louis River estuary (SLRE) in 2012 and 2013. Using multiple gears in a spatially ba...

  6. Larval fish distribution in the St. Louis River estuary

    EPA Science Inventory

    Our objective was to determine what study design, environmental, and habitat variables contribute to the distribution and abundance of larval fish in the St. Louis River estuary. Larval fish habitat associations are poorly understood in Great Lakes coastal wetlands, yet critical ...

  7. Invasion by stages in the St Louis River estuary

    EPA Science Inventory

    The St. Louis River estuary is recognized as an invasive species “hotspot” - the harbor ranks among the top locations in the Great Lakes reporting the first occurrence of new, aquatic non-native species. To date, 18 non-native benthic invertebrate, 4 non-native crusta...

  8. Columbia River Estuary Ecosystem Classification — Concept and application

    USGS Publications Warehouse

    Simenstad, Charles A.; Burke, Jennifer L.; O'Connor, Jim E.; Cannon, Charles; Heatwole, Danelle W.; Ramirez, Mary F.; Waite, Ian R.; Counihan, Timothy D.; Jones, Krista L.

    2011-01-01

    This document describes the concept, organization, and application of a hierarchical ecosystem classification that integrates saline and tidal freshwater reaches of estuaries in order to characterize the ecosystems of large flood plain rivers that are strongly influenced by riverine and estuarine hydrology. We illustrate the classification by applying it to the Columbia River estuary (Oregon-Washington, USA), a system that extends about 233 river kilometers (rkm) inland from the Pacific Ocean. More than three-quarters of this length is tidal freshwater. The Columbia River Estuary Ecosystem Classification ("Classification") is based on six hierarchical levels, progressing from the coarsest, regional scale to the finest, localized scale: (1) Ecosystem Province; (2) Ecoregion; (3) Hydrogeomorphic Reach; (4) Ecosystem Complex; (5) Geomorphic Catena; and (6) Primary Cover Class. We define and map Levels 1-3 for the entire Columbia River estuary with existing geospatial datasets, and provide examples of Levels 4-6 for one hydrogeomorphic reach. In particular, three levels of the Classification capture the scales and categories of ecosystem structure and processes that are most tractable to estuarine research, monitoring, and management. These three levels are the (1) eight hydrogeomorphic reaches that embody the formative geologic and tectonic processes that created the existing estuarine landscape and encompass the influence of the resulting physiography on interactions between fluvial and tidal hydrology and geomorphology across 230 kilometers (km) of estuary, (2) more than 15 ecosystem complexes composed of broad landforms created predominantly by geologic processes during the Holocene, and (3) more than 25 geomorphic catenae embedded within ecosystem complexes that represent distinct geomorphic landforms, structures, ecosystems, and habitats, and components of the estuarine landscape most likely to change over short time periods.

  9. Radiocaesium distribution in the sediment of a Fukushima river estuary

    NASA Astrophysics Data System (ADS)

    Hagiwara, Hiroki; Konishi, Hiromi; Nakanishi, Takahiro; Harada, Hisaya; Tsuruta, Tadahiko

    2016-04-01

    On fluvial discharge, paticulate fractions are the main carrier of radiocaesium from land to aquatic bodies such as rivers, lakes and the sea [1]. However, within river estuaries, where there is a drastic increase in salinity, fine particles generally flocculate (in the size order of several tens μm) before settling out and being deposited on the river bed [2]. In this study, we investigated the sediment records and the distribution of radiocaesium within the estuary of the Odaka river in January 2014, located approximately 17 km north of the Fukushima Dai-ichi Nuclear Power Plant. Based on distribution of salinity, the environment of the Odaka river is divided into three areas; the freshwater area, the estuarine marine area that was filled with saline water from surface to bottom and the brackish area between these two. Radiocaesium deposition ranged from 45 to 1070 kBq m-2 with the inventory of radiocaesium in the estuary being significantly greater in the brackish area relative to both the freshwater and estuarine marine areas. Particle size dependency of radiocaesium concentration in the sediments showed that the distribution with relatively higher concentration was expected in the brackish area. The possibility of flocculation in the brackish area will be discussed. References [1] Nagao, S., Kanamori, M., Ochiai, S., Tomihara, S., Fukushi, K., and Yamamoto, M., 2013, Biogeosciences, v. 10, no. 10, p. 6215-6223. [2] Droppo, I. G., and Ongley, E. D., 1994, Water Research, v. 28, no. 8, p. 1799-1809.

  10. Assessment of trophic status in Changjiang (Yangtze) River estuary

    NASA Astrophysics Data System (ADS)

    Wang, Baodong

    2007-07-01

    The integrated methodology for the assessment of estuarine trophic status (ASSETS), which was extended and refined from the United States National Estuarine Eutrophication Assessment (NEEA), is a multi-parameter assessment system and has been widely used in eutrophication assessment in estuarine and coastal waters. The ASSETS was applied to evaluate the trophic status of the Changjiang (Yangtze) River estuary, one of the largest estuaries in the world. The following main results were obtained: (i) The estuarine export potential is “moderate susceptibility” due to the “moderate” dilution potential and “moderate” flushing potential; (ii) The overall human influence (OHI) index classified the impact of nutrients in the system as “high” due to the high level of nutrient discharge by the river which channels anthropogenic impacts in the catchments to the estuarine system; (iii) The overall eutrophic condition (OEC) in the estuary was classified into the “high” category due to frequent occurrence of nuisance and toxic algal blooms in the mixing and seawater zones; (iv) Since the nutrient loadings (e.g., DIN) in the river is expected to continue to increase in the near future following the population increase and rapid economic growth throughout the drainage basin, the nutrient-related symptoms in the estuary are likely to substantially worsen, which leads to the “worsen high” category for the definition of future outlook (DFO). The combinations of the three components (i.e., OHI, OEC, and DFO) lead to an overall grade as “bad” for the trophic status in the Changjiang River estuary.

  11. Hierarchical Mapping of Landforms along the Columbia River Estuary

    NASA Astrophysics Data System (ADS)

    Cannon, C. M.

    2015-12-01

    Mapping and hierarchical classification of landforms along the Columbia River estuary provides insight into formative geologic, hydrologic, and biologic processes and their associated ecosystems, thereby aiding assessment of future trajectories and restoration approaches. The Columbia River Estuary Ecosystem Classification includes an inventory of landforms along 230 km of riverine estuary between the Pacific Ocean and Bonneville Dam in Oregon and Washington, USA. Landforms were mapped by interpretation of lidar topography supplemented with high-resolution bathymetry, aerial photographs, soil maps, and historical maps. Groupings of landforms were assigned to formative process regimes. These landform groupings relate ecosystems to geophysical processes. Assessment of historical changes to the processes that form and maintain landforms thus has implications for the types of ecosystems that can form and persist along the estuary. The estuary was historically a complex system of channels with a floodplain dominated by extensive tidal wetlands in the lower reaches and backswamp lakes and wetlands in upper reaches. Natural levees flank most channels in the upper reaches, locally including areas of ridge and swale topography and crevasse splays that intrude into backswamps. Other Holocene process regimes affecting floodplain morphology have included volcanogenic deltas, tributary fans, eolian dunes, and landslides. Pre-Holocene landforms are locally prominent and include ancient fluvial deposits and bedrock. Historical changes to streamflow regimes, floodplain isolation, and direct anthropogenic disturbance have resulted in channel narrowing and limited the amount of floodplain that can be shaped by flowing water. Floodplain isolation has caused relative subsidence of tidal floodplains along much of the lower estuary. Most extant landforms are on trajectories strongly influenced by humans and new landforms are mostly created by humans.

  12. Benthic phosphorus regeneration in the Potomac River Estuary

    USGS Publications Warehouse

    Callender, E.

    1982-01-01

    The flux of dissolved reactive phosphate from Potomac riverine and estuarine sediments is controlled by processes occurring at the water-sediment interface and within surficial sediment. In situ benthic fluxes (0.1 to 2.0 mmoles m-2 day-1) are generally five to ten times higher than calculated diffusive fluxes (0.020 to 0.30 mmoles m-2 day-1). The discrepancy between the two flux estimates is greatest in the transition zone (river mile 50 to 70) and is attributd to macrofaunal irrigation. Both in situ and diffusive fluxes of dissolved reactive phosphate from Potomac tidal river sediments are low while those from anoxic lower estuarine sediments are high. The net accumulation rate of phosphorus in benthic sediment exhibits an inverse pattern. Thus a large fraction of phosphorus is retained by Potomac tidal river sediments, which contain a surficial oxidized layer and oligochaete worms tolerant of low oxygen conditions, and a large fraction of phosphorus is released from anoxic lower estuary sediments. Tidal river sediment pore waters are in equilibrium with amorphous Fe (OH)3 while lower estuary pore waters are significantly undersaturated with respect to this phase. Benthic regeneration of dissolved reactive phosphorus is sufficient to supply all the phosphorus requirements for net primary production in the lower tidal river and transition-zone waters of the Potomac River Estuary. Benthic regeneration supplies approximately 25% as much phosphorus as inputs from sewage treatment plants and 10% of all phosphorus inputs to the tidal Potomac River. When all available point source phosphorus data are put into a steady-state conservation of mass model and reasonable coefficients for uptake of dissolved phosphorus, remineralization of particulate phosphorus, and sedimentation of particulate phosphorus are used in the model, a reasonably accurate simulation of dissolved and particulate phosphorus in the water column is obtained for the summer of 1980. ?? 1982 Dr W. Junk

  13. Environmental contaminants in bald eagles in the Columbia River estuary

    SciTech Connect

    Anthony, R.G.; Garrett, M.G. ); Schuler, C.A. )

    1993-01-01

    Eggs, blood, and carcasses of bald eagles (Haliaeetus leucocephalus) and fish were collected and breeding success of eagles was monitored in the Columbia River estuary, 1980-87, to determine if contaminants were having an effect on productivity. High levels of dichloro diphenyl dichloroethylene (DDE), polychlorinated biphenyls (PCB's), and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) were found in eggs, blood from adults, and 2 eagle carcasses. Detectable levels of DDE and PCB's were found in blood of nestlings indicating they were exposed to these contaminants early in life. Increasing concentrations of DDE and PCB's with age also indicated accumulation of these contaminants. Adult eagles also had higher levels of mercury (Hg) in blood than subadults or young indicating accumulation with age. The high levels of DDE and PCB's were associated with eggshell thinning ([bar x] = 10%) and with productivity ([bar x] = 0.56 young/occupied site) that was lower than that of healthy populations (i.e., [ge]1.00 young/occupied site). DDE and PCB's had a deleterious effect on reproduction of bald eagles in the estuary. The role dioxins play in eagle reproduction remains unclear, but concentrations in eagle eggs were similar to those in laboratory studies on other species where dioxins adversely affected hatchability of eggs. Probable source of these contaminants include dredged river sediments and hydroelectric dams, and the proper management of each may reduce the amount of contaminants released into the Columbia River estuary. 46 refs., 1 fig., 4 tabs.

  14. Salinity and turbidity distributions in the Brisbane River estuary, Australia

    NASA Astrophysics Data System (ADS)

    Yu, Yingying; Zhang, Hong; Lemckert, Charles

    2014-11-01

    The Brisbane River estuary (BRE) in Australia not only plays a vital role in ecosystem health, but is also of importance for people who live nearby. Comprehensive investigations, both in the short- and long-term, into the salinity and turbidity distributions in the BRE were conducted. Firstly, the analysis of numerical results revealed that the longitudinal salinity varied at approximately 0.45 and 0.61 psu/h during neap and spring tides, respectively. The turbidity stayed at a higher level and was less impacted by tide in the upper estuary, however, the water cleared up while the tide changed from flood to ebb in the mid and lower estuary. The second investigation into the seasonal variations of salinity and turbidity in the BRE was conducted, using ten-year field measurement data. A fourth-order polynomial equation was proposed, describing the longitudinal variation in salinity dilution changes as the upstream distance in the BRE during the wet and dry seasons. From the observation, the mid and upper estuaries were vertically well-mixed during both seasons, but the lower BRE was stratified, particularly during the wet season. The estuary turbidity maximum (ETM) zone was about 10 km longer during the wet season than the dry season. Particular emphasis was given to the third investigation into the use of satellite remote sensing techniques for estimation of the turbidity level in the BRE. A linear relationship between satellite observed water reflectance and surface turbidity level in the BRE was validated with an R2 of 0.75. The application of satellite-observed water reflectance therefore provided a practical solution for estimating surface turbidity levels of estuarine rivers not only under normal weather conditions, but also during flood events. The results acquired from this study are valuable for further hydrological research in the BRE and particularly prominent for immediate assessment of flood impacts.

  15. Linking the river to the estuary: influence of river discharge on tidal damping

    NASA Astrophysics Data System (ADS)

    Cai, H.; Savenije, H. H. G.; Toffolon, M.

    2013-07-01

    The effect of river discharge on tidal damping in estuaries is explored within one consistent theoretical framework where analytical solutions are obtained by solving four implicit equations, i.e., the phase lag, the scaling, the damping and the celerity equation. In this approach the damping equation is obtained by subtracting the envelope curves of high water and low water occurrence, taking into account that the flow velocity consists of a tidal and river discharge component. Different approximations of the friction term are considered in deriving the damping equation, resulting in as many analytical solutions. In this framework it is possible to show that river discharge affects tidal damping primarily through the friction term. The application to the Modaomen and Yangtze estuaries demonstrates that the influence of river discharge on tidal damping can be significant in the upstream part of an estuary where the ratio of river flow to tidal flow amplitude is substantial. The analytical model is able to describe the main tidal dynamics with realistic roughness values in the upper part of the estuary, while a model with negligible river discharge can be made to fit observations only with unrealistically high roughness values. Moreover, the damping equation can be used to estimate river discharge on the basis of observed tidal damping, which makes the proposed analytical model a tool to obtain indirect information about quantities that are difficult to measure in the tidal region.

  16. Trace elements and radionuclides in the Connecticut River and Amazon River estuary

    SciTech Connect

    Dion, E.P.

    1983-01-01

    The Connecticut River, its estuary and the Amazon River plume were studied to elucidate processes which control the flux of nuclides to the sea. Major ions (Ca, Mg, Na, Cl, Bicarbonate) and selected trace elements (Ra, Ba, Cu, Si) are introduced to the Connecticut River in proportion to the total dissolved load of various groundwaters. Si, Ra, and Ba are subject to removal from solution by seasonal diatom productivity; whereas the other groundwater-derived elements are found in proportion to TDS both time and space. These nuclides are released in the estuary when a portion of the Ra, Ba, and Si in riverine biogenic detritus is trapped in salt marshes and coves bordering the estuary where it redissolves and is exported to the main river channel at ebb tide. In the Amazon River estuary, the Ra and Ba are released in mid-salinity waters. Ra and Ba together with Si are subsequently removed by diatom productivity as reflected in increased Ra and Ba in the suspended particles and depleted dissolved nuclide concentrations in samples from the high productivity zone. In both the Connecticut River system and the Amazon River plume, Cu behaves conservatively; whereas the fates of Fe and Al are linked to soil-derived humic acids. Trace elements in Amazon plume sediments are found simply in proportion to the percentage of fine-grained size materials, despite low Th-228/Ra-228 mean residence times in the plume and the presence of Cs-137 in the sediment column. Estimates of the total flux of nuclides to the oceans can best be calculated on a mass balance basis using groundwater inputs. Unless significant repositories for nuclides exist in the river-estuarine system, the groundwater flux of dissolved nuclides is net flux to the ocean despite the reactions which occur in both rivers and estuaries.

  17. Numerical modeling of circulation in high-energy estuaries: A Columbia River estuary benchmark

    NASA Astrophysics Data System (ADS)

    Kärnä, Tuomas; Baptista, António M.; Lopez, Jesse E.; Turner, Paul J.; McNeil, Craig; Sanford, Thomas B.

    2015-04-01

    Numerical modeling of three-dimensional estuarine circulation is often challenging due to complex flow features and strong density gradients. In this paper the skill of a specific model is assessed against a high-resolution data set, obtained in a river-dominated mesotidal estuary with autonomous underwater vehicles and a shipborne winched profiler. The measurements provide a detailed view of the salt wedge dynamics of the Columbia River estuary. Model skill is examined under contrasting forcing conditions, covering spring freshet and autumn low flow conditions, as well as spring and neap tides. The data set provides a rigorous benchmark for numerical circulation models. This benchmark is used herein to evaluate an unstructured grid circulation model, based on linear finite element and finite volume formulations. Advection of momentum is treated with an Eulerian-Lagrangian scheme. After the model's sensitivity to grid resolution and time step is examined, a detailed skill assessment is provided for the best model configuration. The simulations reproduce the timing and tidal asymmetry of salinity intrusion. Sharp density gradients, however, tend to be smoothed out affecting vertical mixing and gravitational circulation. We show that gravitational salt transport is underestimated in the model, but is partially compensated through tidal effects. The discrepancy becomes most pronounced when the stratification is strongest, i.e., under high river discharge and neap tide conditions.

  18. The Mattole River Estuary: Restoration Efforts in a Dynamic System

    NASA Astrophysics Data System (ADS)

    Barber, D.; Liquori, M.

    2010-12-01

    Despite extensive scientific advancement integrating our understanding of hydrology, geomorphology, and ecology in recent decades, the application of restoration in the field has been slow to evolve. This presentation will highlight 20 years of restoration practices in the Mattole River Estuary and how these practices have informed our understanding of this complex system. The Mattole River Watershed is a 304 square-mile basin located near the Mendocino Triple Junction in a remote region of California known as the “The Lost Coast” for its rugged mountains and undeveloped coastline. In addition to numerous species of fish, mammals, and over 250 bird species, the Mattole Watershed is home to three Federally-listed Threatened salmonids: California Coastal Chinook salmon, Southern Oregon/Northern California Coasts coho salmon, and Northern California steelhead trout. The 64 mile-long river meets the Pacific Ocean at the northern end of the 64,000 acre King Range National Conservation Area (KRNCA), managed by the Bureau of Land Management (BLM). The watershed is dynamic, with some of the nation’s highest annual rainfall (mean = 158 cm/yr), naturally occurring steep slopes, erosive sedimentary geology, and frequent earthquakes. All of these factors have amplified the negative effects of extensive logging and associated road building between 1945 and 1970, which left a legacy of increased sediment loads and high water temperatures that have yet to recover to pre-disturbance levels, severely impairing riparian and aquatic habitats. Prior to major land disturbances, the Mattole estuary/lagoon was notable for its deep, thermally-stratified pools and numerous functioning north and south bank slough channels that flushed sediments from the river and received marine water. As flows decline in late spring, a sandbar closes off surface flow from the river to the Pacific Ocean, forming a lagoon, which persists until flows increase in the fall. Today, the estuary is poor

  19. Linking the river to the estuary: influence of river discharge on tidal damping

    NASA Astrophysics Data System (ADS)

    Cai, H.; Savenije, H. H. G.; Toffolon, M.

    2014-01-01

    The effect of river discharge on tidal damping in estuaries is explored within one consistent theoretical framework where analytical solutions are obtained by solving four implicit equations, i.e. the phase lag, the scaling, the damping and the celerity equation. In this approach the damping equation is obtained by subtracting the envelope curves of high water and low water occurrence, taking into account that the flow velocity consists of a tidal and river discharge component. Different approximations of the friction term are considered in deriving the damping equation, resulting in as many analytical solutions. In this framework it is possible to show that river discharge affects tidal damping primarily through the friction term. It appears that the residual slope, due to nonlinear friction, can have a substantial influence on tidal wave propagation when including the effect of river discharge. An iterative analytical method is proposed to include this effect, which significantly improved model performance in the upper reaches of an estuary. The application to the Modaomen and Yangtze estuaries demonstrates that the proposed analytical model is able to describe the main tidal dynamics with realistic roughness values in the upper part of the estuary where the ratio of river flow to tidal flow amplitude is substantial, while a model with negligible river discharge can be made to fit observations only with unrealistically high roughness values.

  20. Metals in the sediments along the Hudson River estuary

    SciTech Connect

    Gibbs, R.J. )

    1994-01-01

    The distribution of metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in bottom and suspended sediments from the ocean up the Hudson River estuary for 70 km were analyzed. The bottom sediments has a metal concentration maximum in the harbor. Everywhere studied, the metal concentrations in suspension are much higher than in the bottom sediments by 30 times for Cd, 20 times for Cu, and 10 to 15 times for Co, Cr, Ni, Pb, and Zn. The composition of metals in the suspended material varied along the estuary with a large metal maximum in the harbor and again in Haverstraw Bay. By standardizing toxic metal concentrations to Fe, a maximum level of pollution in New York Harbor is indicated, along with a lesser maximum in Haverstraw Bay.

  1. Macrobenthic community in the Xiaoqing River Estuary in Laizhou Bay, China

    NASA Astrophysics Data System (ADS)

    Luo, Xianxiang; Zhang, Shanshan; Yang, Jianqiang; Pan, Jinfen; Tian, Lin; Zhang, Longjun

    2013-09-01

    The macrobenthic community of the Xiaoqing River Estuary and the adjacent sea waters was investigated in May and November 2008, August 2009, and May and September 2010, respectively. A total of 95 species of macrobenthos were identified in the five cruises and most of them were polychaetes (46.39%), mollusks (28.86%) and crustaceans (20.62%). The Shannon-Wiener index of macrobenthos was lower than 2 in 67% sites. Along the stream channel, estuary and the coastal waters, the species of polychaetes reduced gradually, while the abundance increased at first and then decreased. The abundance was the biggest at regions with salinity of 5-20 in the estuary. The species and abundance of mollusks and crustaceans increased gradually. As for seasonal distribution, the species, abundance and biomass were higher in spring and lower in summer and autumn. Contemporaneously compared with Laizhou Bay and Yellow River Estuary, the species of macrobenthos appeared in the Xiaoqing River Estuary were much less, while the percentage of polychaetes was higher. Abundance and biomass were higher in Xiaoqing River estuary, then consequently followed by Laizhou Bay and Yellow River Estuary. The dominant species in Xiaoqing River Estuary was polychaete, and Layzhou Bay mollusk. The community structure characteristics of macrobenthos in the Xiaoqing River Estuary revealed a significant pollution status in this region.

  2. Sedimentary framework of the Potomac River estuary, Maryland

    USGS Publications Warehouse

    Knebel, Harley J.; Martin, E. Ann; Glenn, J.L.; Needell, Sally W.

    1981-01-01

    Analyses of seismic-reflection profiles, sediment cores, grab samples, and side-scan sonar records, along with previously collected borehole data, reveal the characteristics, distribution, and geologic history of the shallow strata beneath the Potomac River estuary. The lowermost strata are sediments of the Chesapeake Group (lower Miocene to lower Pleistocene) that crop out on land near the shore but are buried as much as 40 m below the floor of the estuary. The top of these sediments is an erosional unconformity that outlines the Wisconsinan valley of the Potomac River. This valley has a sinuous trend, a flat bottom, a relief of 15 to 34 m, and axial depths of 34 to 54 m below present sea level. During the Holocene transgression of sea level, the ancestral valley was filled with as much as 40 m of sandy and silty, fluvial-to-shallow estuarine sediments. The fill became the substrate for oyster bars in the upper reach and now forms most marginal slopes of the estuary. Since sea level approached its present position (2,000 to 3,000 yr ago), the main channel has become the locus of deposition for watery, gray to black clay or silty clay, and waves and currents have eroded the heterogeneous Quaternary sediments along the margins, leaving winnowed brown sand on shallow shoreline flats. Pb-210 analyses indicate that modern mud is accumulating at rates ranging from 0.16 to 1.80 cm/yr, being lowest near the mouth and increasing toward the head of the estuary. This trend reflects an increased accumulation of fine-grained fluvial sediments near the turbidity maximum, similar to that found in nearby Chesapeake Bay. The present annual accumulation of mud is about 1.54 million metric tons; the cumulative mass is 406 million metric tons.

  3. Oysters, estuaries, and Late Pleistocene-Holocene sea level, northeastern Gulf of Mexico

    SciTech Connect

    Schroeder, W.W. . Marine Science Program); Shultz, A.W. )

    1993-03-01

    The timing and magnitude of global sea level fluctuations over the past 35 kyr remain nondum ostenduntur after three decades of study. The construction of local relative sea level histories is often complicated by the need to assess regional tectonic and climatic components together. The authors attempt to contribute to an understanding of sea level fluctuations in the northeastern Gulf of Mexico through the application of faunal tracking, using fossil oyster shells as indicators of paleoestuarine environments. They assume that sites on the continental shelf where oysters have been collected were coastal and therefore are reasonable approximations of past shoreline locations and sea-level elevations. They acknowledge that this assumption is a leap of faith for some observers, but is justified as a provisional step toward an independent determination. Insights into Quaternary coastal paleogeography are gathered from locations and radiocarbon ages of American oyster (Crassostrea virginica) shells collected from the Alabama continental shelf. Prior to the onset of the last Wisconsinan glaciation (35 to 26 kyr BP), estuaries occupied a zone 20 to 25 km seaward of today's coastline. As glaciation increased and sea level was lowered (23 to 21 kyr BP), open coastal estuarine conditions developed southward. Oysters dating from the lowstand period (20 to 16 kyr BP) have not been collected. As sea level rose over the next 10 kyr (16 to 6 kyr BP), estuaries were displaced northward in steps. This data on depths and ages can be viewed as supporting an interpretation of fluctuating Holocene sea level, rather than a steady sea-level rise.

  4. Transport of fallout and reactor radionuclides in the drainage basin of the Hudson River estuary

    SciTech Connect

    Simpson, H.J.; Linsalata, P.; Olsen, C.R.

    1982-01-01

    The transport and fate of Strontium 90, Cesium 137 and Plutonium 239, 240 in the Hudson River Estuary is discussed. Rates of radionuclide deposition and accumulation over time and space are calculated for the Hudson River watershed, estuary, and continental shelf offshore. 37 references, 7 figures, 15 tables. (ACR)

  5. Hydrodynamic controls on oxygen dynamics in a riverine salt wedge estuary, the Yarra River estuary, Australia

    NASA Astrophysics Data System (ADS)

    Bruce, L. C.; Cook, P. L. M.; Teakle, I.; Hipsey, M. R.

    2014-04-01

    Oxygen depletion in coastal and estuarine waters has been increasing rapidly around the globe over the past several decades, leading to decline in water quality and ecological health. In this study we apply a numerical model to understand how salt wedge dynamics, changes in river flow and temperature together control oxygen depletion in a micro-tidal riverine estuary, the Yarra River estuary, Australia. Coupled physical-biogeochemical models have been previously applied to study how hydrodynamics impact upon seasonal hypoxia; however, their application to relatively shallow, narrow riverine estuaries with highly transient patterns of river inputs and sporadic periods of oxygen depletion has remained challenging, largely due to difficulty in accurately simulating salt wedge dynamics in morphologically complex areas. In this study we overcome this issue through application of a flexible mesh 3-D hydrodynamic-biogeochemical model in order to predict the extent of salt wedge intrusion and consequent patterns of oxygen depletion. The extent of the salt wedge responded quickly to the sporadic riverine flows, with the strength of stratification and vertical density gradients heavily influenced by morphological features corresponding to shallow points in regions of tight curvature ("horseshoe" bends). The spatiotemporal patterns of stratification led to the emergence of two "hot spots" of anoxia, the first downstream of a shallow region of tight curvature and the second downstream of a sill. Whilst these areas corresponded to regions of intense stratification, it was found that antecedent conditions related to the placement of the salt wedge played a major role in the recovery of anoxic regions following episodic high flow events. Furthermore, whilst a threshold salt wedge intrusion was a requirement for oxygen depletion, analysis of the results allowed us to quantify the effect of temperature in determining the overall severity and extent of hypoxia and anoxia. Climate

  6. Trace metals geochemistry of Bengkulu river and estuary

    NASA Astrophysics Data System (ADS)

    Firdaus, M. Lutfi; Darti, Puspa; Alwi, Wiwit; Swistoro, Eko; Sundaryono, Agus; Ruyani, Aceng

    2015-09-01

    Unique feature of Indonesian archipelago in addition to its location that settled between the Pacific Ocean and the Indian Ocean has made Indonesian seas as important parts of the world ocean system. In contrast, research on Indonesian seas including its marine geochemistry is scarce. Research findings have proven that Indonesian seas and its characteristics, such as Indonesian throughflow, are important in the seawater thermohaline circulation that affect world's global climate. The transports of mass and heat from the Pacific into the Indian Ocean are crucial for the oceanic circulation and sea surface temperatures. It is only until recently known that water masses movement could be traced using chemical elements such as Zr and Hf. In modern ocean, sources of these chemicals are mostly from continents. Chemicals had been brought to the oceans through river, estuary, coastal and eventually open seawater. We have analyzed selected important trace metals of Bengkulu river and estuary starting from upper stream of Bengkulu River to coastal seawater of the Indian Ocean. Concentrations of trace metals in the sample were determined by inductively coupled plasma - optical emission spectrometry (ICP-OES). Dissolved and labile particulate concentrations of Al, Fe, Mn, V, Sr and Zn are reported in this study.

  7. Hydrodynamics and Water Quality: Modeling Rivers, Lakes, and Estuaries

    NASA Astrophysics Data System (ADS)

    Opdyke, Daniel

    2008-09-01

    The modeling of lakes, rivers, and estuaries is a fascinating subject that combines interesting facets of mathematics, statistics, physics, chemistry, and biology. Because of the complexity of natural systems, such modeling is always an approximation of the real world-and sometimes not a very good one. It is for this reason that modeling is not just science but also art. It is also for this reason that there are few good texts offering practical advice on modeling. Hydrodynamics and Water Quality makes a valiant attempt but is only partially successful because of the book's narrow focus on one family of models and an inconsistent presentation.

  8. Quantifying nitrogen inputs to the Choptank River estuary

    NASA Astrophysics Data System (ADS)

    Mccarty, G.; Hapeman, C. J.; Sadeghi, A. M.; Hively, W. D.; Denver, J. M.; Lang, M. W.; Downey, P. M.; Rice, C. P.

    2015-12-01

    The Chesapeake Bay is the largest estuary in the US, and over 50% of its streams have been rated as poor or very poor, based on the biological integrity yearly index. The Choptank River, a Bay tributary on the Delmarva Peninsula, is dominated by intensive corn and soybean farming associated with poultry and some dairy production. The Choptank River is under Environmental Protection Agency (USEPA) total maximum daily load restrictions. However, reducing nonpoint source pollution contributions from agriculture requires that source predictions be improved and that mitigation and conservation measures be properly targeted. Therefore, new measurement strategies have been implemented. In-situ sensors have been deployed adjacent to US Geological Survey gauging stations in the Tuckahoe and Greensboro sub-basins of the Choptank River watershed. These sensors measure stream water concentrations of nitrate along and water quality parameters every 30 min. Initial results indicate that ~40% less nitrate is exported from the Greensboro sub-basin, even though the total amount of agricultural land use is similar to that in the Tuckahoe sub-basin. This is most likely due to more efficient nitrate processing in the Greensboro sub-basin where the amount of cropland on poorly-drained soils is much larger. Another potential nitrogen source to the Choptank River estuary is atmospheric deposition of ammonia. Over 550 million broilers are produced yearly on the Delmarva Peninsula potentially leading to the release of 20,000 Mtons of ammonia. USEPA recently estimated that as much as 22% of nitrogen in the Bay is due to ammonia deposition. We have initiated a collaborative effort within the LTAR network to increase coverage of ammonia sampling and to explore the spatial and temporal variability of ammonia, particularly in the Choptank River watershed. All these measurements will be useful in improving the handling of nitrogen sources and its fate and transport in the Chesapeake Bay model.

  9. The hydrodynamic response of the York River estuary to Tropical Cyclone Isabel, 2003

    NASA Astrophysics Data System (ADS)

    Gong, Wenping; Shen, Jian; Reay, William G.

    2007-07-01

    Hurricane Isabel made landfall along the North Carolina coast on September 18, 2003 (UTC 17:00) and the storm surge exceeded 2.0 m in many areas of the Chesapeake Bay and in the York River estuary. River flooding occurred subsequently, and the peak river discharge reached 317 and 104 m 3 s -1 in the Pamunkey and Mattaponi rivers, respectively. The York River estuary experienced both storm surge and river flooding during the event and the estuary dynamics changed dramatically. This study investigates the hydrodynamics of the York River estuary in response to the storm surge and high river inflows. A three-dimensional model was used to investigate the changes of estuarine stratification, longitudinal circulation, salt flux mechanisms, and the recovery time required for the estuary to return to its naturally evolved condition without the storm. Results show that the salt flux was mainly caused by advection, which was induced by the barotropic gradient during the storm event. The net salt flux increased by a factor of 30 during the rise of the storm surge. However, the large amount of salt transported into the estuary was quickly transported out of the estuary as the barotropic gradient reversed during the descent of the storm surge. Subsequent high freshwater inflow influenced the estuarine circulation substantially. The estuary changed from a partially mixed estuary to a very stratified estuary for a prolonged period. The model results show that it will take about 4 months for the estuary to recover to its naturally evolved salinity distribution after the impacts of the storm surge and freshwater pulse.

  10. River-tide dynamics: Exploration of nonstationary and nonlinear tidal behavior in the Yangtze River estuary

    NASA Astrophysics Data System (ADS)

    Guo, Leicheng; van der Wegen, Mick; Jay, David A.; Matte, Pascal; Wang, Zheng Bing; Roelvink, Dano; He, Qing

    2015-05-01

    River-tide dynamics remain poorly understood, in part because conventional harmonic analysis (HA) does not cope effectively with nonstationary signals. To explore nonstationary behavior of river tides and the modulation effects of river discharge, this work analyzes tidal signals in the Yangtze River estuary using both HA in a nonstationary mode and continuous wavelet transforms (CWT). The Yangtze is an excellent natural laboratory to analyze river tides because of its high and variable flow, its length, and the fact that there are do dams or reflecting barriers within the tidal part of the system. Analysis of tidal frequencies by CWT and analysis of subtidal water level and tidal ranges reveal a broad range of subtidal variations over fortnightly, monthly, semiannual, and annual frequencies driven by subtidal variations in friction and by variable river discharges. We employ HA in a nonstationary mode (NSHA) by segregating data within defined flow ranges into separate analyses. NSHA quantifies the decay of the principal tides and the modulation of M4 tide with increasing river discharges. M4 amplitudes decrease far upriver (landward portion of the estuary) and conversely increase close to the ocean as river discharge increases. The fortnightly frequencies reach an amplitude maximum upriver of that for over tide frequencies, due to the longer wavelength of the fortnightly constituents. These methods and findings should be applicable to large tidal rivers globally and have broad implications regarding management of navigation channels and ecosystems in tidal rivers.

  11. Occurrence and distribution of dissolved tellurium in Changjiang River estuary

    NASA Astrophysics Data System (ADS)

    Wu, Xiaodan; Song, Jinming; Li, Xuegang

    2014-03-01

    With the implementation of the GEOTRACES program, the biogeochemical cycle and distribution of tellurium (Te) in marine environments are becoming increasing environmental concerns. In this study, the concentration of dissolved Te in the Changjiang (Yangtze) River estuary and nearby waters was determined in May 2009 by hydride-generation atomic fluorescence spectrometry to elucidate the abundance, dominant species, distribution, and relationship with environmental factors. Results show that: (1) dissolved Te was low owing to its low abundance in the Earth's crust, high insolubility in water, and strong affinity to particulate matter; (2) Te(IV) and Te(VI) predominated in surface water. Te(VI) was the dominant species in bottom water, and Te(IV) was the minor species; (3) Horizontally, resulting from low phytoplankton metabolism and the weak reduction from Te(VI) to Te(IV) in the shore, Te(IV) was concentrated in the central zone instead of the coastal region. However, Te(VI) was abundant near the mouth of the Changjiang River where the Changjiang water is diluted and in the area to the south where the Taiwan Warm Current invaded. In the adsorption-desorption process, Te(IV) was negatively related to suspended particulate matter (SPM), indicating that it was adsorbed by particulate matter. While for Te(VI), the positive correlation with SPM suggested that it was desorbed from the solid phase. In the estuary, dissolved Te had a negative correlation to salinity. However, it deviated from the dilution line in high-salinity regions due to the invasion of the Taiwan Warm Current and the mineralization of organic matter. The relationship between Te(IV) and SPM nutrients indicated that it was more bioavailable and more related to phosphorus than to nitrogen. Progress in the field is slow and more research is needed to quantify the input of Te to the estuary and evaluate the biochemical role of organisms.

  12. Geochemical phases of metals in Hudson River estuary sediments

    SciTech Connect

    Stamoulis, S.; Gibbs, R.J.; Menon, M.G.

    1996-08-01

    Bottom sediment samples were collected from six location along a section of the Hudson River Estuary, 5.3 to 82.7 km from the ocean. These samples were analyzed for particle and, due to the bimodal distribution of the sediment, were seperated into two size fractions, fine (<7.8 um) and coarse (7.8-62 um). These fractions were subject to a sequential chemical phase extraction procedure to differenciate the ion exchangeable, carbonate, metallic oxide coating, and organic phases. The extracted phases were analyzed with an inductively coupled plasma atomic emission spectrophotometer for Cd, Co, Cc, Cu, Fe, Ni, Pb, and Zn. Metals were found to be associated largely with fine particle-size fraction. The concentration of fine particles (especially the <2 um size mode within the fine fraction) is a crucial in influencing overall metal content. This is evidenced by strong correlations between the <2 {mu}m or clay mode and concentrations in the metallic-oxide coating phase. Various metal/metal relationships exist among the phases and fractions studied and are highlighted by strong correlations, such as Ni and Zn, and Cu and Cd. The trends associated among the metal and mud concentrations are significant in terms of assessing the bioavailability of heavy metals within the river and estuary system, and as a result, provide valuable insight into the ultimate fate of pollutants which are introduced to this unique environment. 24 refs., 5 figs., 2 tabs.

  13. Suspended Sediment Exchange through the Sub-tropical Richmond River Estuary, Australia: a Balance Approach

    NASA Astrophysics Data System (ADS)

    Hossain, S.; Eyre, B.

    2002-10-01

    Major sources of suspended sediments and their exchanges with the continental shelf for the Richmond River estuary were investigated during two hydrological years. Of the major sources of suspended sediment inputs into the Richmond River estuary, fluvial input from the upper catchment area was about 92-99% of the total yearly balance, and more than 90% of this fluvial sediment was transported into the estuary during less than 5% time of the year. The Richmond River estuary received net sediment input of about 1-2% of the total yearly balance from the continental shelf during dry seasons when upper catchment freshwater input was less than 45×10 6 m 3. Bank erosion in the Richmond River estuary was least (<1%) during low to moderate floods mainly due to river training works and large mangrove coverage along the banks. Percentage of sediment export from the Richmond River estuary depends on the magnitude of floods, which was evident from 47% export during dry year when the estuary experienced a minor flood compared to 88% export during the wet year when the estuary experienced one minor and one moderate flood.

  14. Decadal to Millennial Sedimentation Patterns of the Hudson River Estuary

    NASA Astrophysics Data System (ADS)

    Jones, M.; McHugh, C. M.; Burckle, L.; Pekar, S.; Pereira, G.; Ryan, W. B.; Bell, R.; Carbotte, S.

    2002-12-01

    The Hudson River Estuary (HRE) is adjacent to large metropolitan areas including New York City. Understanding the variable energy conditions for transporting sediments is key to deal with environmental pollution such as the controversial burial and dredging of PCB's in the HRE. We studied sediment transport in the HRE by examining more than 150 cores and grab samples interpreted within the framework of acoustic images. The HRE sedimentary environments were defined based on quantitative estimates of grain size, sedimentary structures, bioturbation, and sedimentation rates and were divided into: channel, channel banks, subtidal flats, tributaries, and islands. Diatom assemblages were used to determine the extent of salt-water intrusion and sediment reworking in the estuary. Along a longitudinal profile, the estuary can be subdivided into: (1) sandy inner fluvial (furthest upstream), (2) muddy central portions, and (3) sandy outer marine. We classified sedimentary facies for the central and fluvial parts of the system (1 and 2). The HRE basin is nearly filled with sediment and tidal energy is focused within the channel and its banks. In the central basin where the estuary is wide (up to 4 km), flood currents are more energetic along the eastern channel bank and the ebb currents lead to minor sediment deposition on the western bank, but only where the system is out of equilibrium with its sediment load. The energy of the tides is accentuated along narrow segments of the estuary that are locally constrained by gorges of the Hudson Valley Highlands leading to erosion and the trapping of sediments. Beyond the banks of the channel, the subtidal flats that were filled with sediment by 0.5 to 3ka, are tranquil environments where the sediment is homogenized by bioturbation and reworked by waves as the estuary shallowed. Occasional high-energy events, (possibly flood-related) eroded the subtidal flats sediment as shown by rare rip-up clasts found in the cores. The inner

  15. Subtidal sea level variability in a shallow Mississippi River deltaic estuary, Louisiana

    USGS Publications Warehouse

    Snedden, G.A.; Cable, J.E.; Wiseman, W.J., Jr.

    2007-01-01

    The relative roles of river, atmospheric, and tidal forcings on estuarine sea level variability are examined in Breton Sound, a shallow (0.7 m) deltaic estuary situated in an interdistributary basin on the Mississippi River deltaic plain. The deltaic landscape contains vegetated marshes, tidal flats, circuitous channels, and other features that frictionally dissipate waves propagating through the system. Direct forcing by local wind stress over the surface of the estuary is minimal, owing to the lack of significant fetch due to landscape features of the estuary. Atmospheric forcing occurs almost entirely through remote forcing, where alongshore winds facilitate estuary-shelf exchange through coastal Ekman convergence. The highly frictional nature of the deltaic landscape causes the estuary to act as a low-pass filter to remote atmospheric forcing, where high-frequency, coastally-induced fluctuations are significantly damped, and the damping increases with distance from the estuary mouth. During spring, when substantial quantities of controlled Mississippi River inputs (q?? = 62 m3 s-1) are discharged into the estuary, upper estuary subtidal sea levels are forced by a combination of river and remote atmospheric forcings, while river effects are less clear downestuary. During autumn (q?? = 7 m3 s-1) sea level variability throughout the estuary is governed entirely by coastal variations at the marine boundary. A frequency-dependent analytical model, previously used to describe sea level dynamics forced by local wind stress and coastal forcing in deeper, less frictional systems, is applied in the shallow Breton Sound estuary. In contrast to deeper systems where coastally-induced fluctuations exhibit little or no frictional attenuation inside the estuary, these fluctuations in the shallow Breton Sound estuary show strong frequency-dependent amplitude reductions that extend well into the subtidal frequency spectrum. ?? 2007 Estuarine Research Federation.

  16. Mechanisms of land sea interactions the distribution of metals and sedimentary organic matter in sediments of a river-dominated Mediterranean karstic estuary

    NASA Astrophysics Data System (ADS)

    Sondi, Ivan; Lojen, Sonja; Juračić, Mladen; Prohić, Esad

    2008-10-01

    This paper examines disposal of metals and the origin, characteristics, and distribution of sedimentary organic matter (SOM) in a Mediterranean karstic estuary in the north-eastern Adriatic. This environment offers a real-time, small model system for studies of geochemical processes in microtidal Mediterranean estuaries that are infilling with sediments and classified as river-dominated disequilibrium estuaries. The results have shown that the longitudinal distribution of heavy metals in sediments follows the sedimentation dynamics and deposition pattern of river-borne, clay mineral particles. The highest concentration of metals was found in the restricted upper part of the estuary, characterized by rapid deposition of clay particles and terrestrial sedimentary organic matter, and decreases toward the open sea. The vertical distribution of metals in sediment cores depends on the prevailing pH and Eh conditions. Significant increases of the concentrations of metals in the uppermost strata are the result of recent anthropogenic inputs. The share of the terrestrial component in SOM, estimated by N/C org atomic ratios and δ 13C values, decreases with distance from the river mouth. The small vertical variation in δ 13C values of SOM indicates that a fast sedimentation rate overrides the diagenetically determined decomposition. The results obtained indicate that river-borne inorganic particles, natural terrigenous organic material, and anthropogenic metal loads are trapped in sediments of the estuarine system. Under the prevailing conditions, there is negligible transport towards the open sea.

  17. Population biology of the mangrove crab Ucides cordatus (Decapoda: Ucididae) in an estuary from semiarid northeastern Brazil.

    PubMed

    Leite, Marcos de Miranda Leão; Rezende, Carla Ferreira; Silva, José Roberto Feitosa

    2013-12-01

    The mangrove crab Ucides cordatus is an important resource of estuarine regions along the Brazilian coast. U. cordatus is distributed from Florida, U.S.A., to the coast of Santa Catarina, Brazil. The species plays an important role in processing leaf litter in the mangroves, which optimizes the processes of energy transfer and nutrient cycling, and is considered a keystone species in the ecosystem. Population declines have been reported in different parts of the Brazilian coast. In the present study we evaluated aspects of the population structure, sex ratio and size at morphological sexual maturity. We analyzed 977 specimens collected monthly over 24 months (2010-2012), in a mangrove of the Jaguaribe River, in the municipality of Aracati on the East coast of Ceará state, Northeastern Brazil. The study area has a mild semiarid tropical climate, with mean temperatures between 26 and 28 degrees C. The area is located within the eco-region of the semiarid Northeast coast, where mangroves occur in small areas and estuaries are affected by mesomareal regimes. The population structure was evaluated by the frequency distribution of size classes in each month, and the overall sex ratio was analyzed using the chi-square test. Size at morphological sexual maturity was estimated based on the allometry of the cheliped of the males and the abdomen width of the females, using the program REGRANS. The size-frequency distribution was unimodal in both sexes. The overall sex ratio (M:F) (1:0.6) was significantly different from 1:1. Analysis of the sex ratio by size class showed that the proportion of males increased significantly from size class 55-60 mm upward, and this pattern persisted in the larger size classes. In the smaller size classes the sex ratio did not differ from 1:1. The size at morphological sexual maturity was estimated at a carapace width (CW) of 52 mm and 45 mm for males and females, respectively. Analysis of the population parameters indicated that the

  18. REE in the Great Whale River estuary, northwest Quebec

    NASA Technical Reports Server (NTRS)

    Goldstein, Steven J.; Jacobsen, Stein B.

    1988-01-01

    A report on REE concentrations within the estuary of the Great Whale River in northwest Quebec and in Hudson Bay is given, showing concentrations which are less than those predicted by conservative mixing of seawater and river water, indicating removal of REE from solution. REE removal is rapid, occurring primarily at salinities less than 2 percent and ranges from about 70 percent for light REE to no more than 40 percent for heavy REE. At low salinity, Fe removal is essentially complete. The shape of Fe and REE vs. salinity profiles is not consistent with a simple model of destabilization and coagulation of Fe and REE-bearing colloidal material. A linear relationship between the activity of free ion REE(3+) and pH is consistent with a simple ion-exchange model for REE removal. Surface and subsurface samples of Hudson Bay seawater show high REE and La/Yb concentrations relative to average seawater, with the subsurface sample having a Nd concentration of 100 pmol/kg and an epsilon(Nd) of -29.3; characteristics consistent with river inputs of Hudson Bay. This indicates that rivers draining the Canadian Shield are a major source of nonradiogenic Nd and REE to the Atlantic Ocean.

  19. Detection of major river bed changes in the River Ebro (north-eastern Spain)

    NASA Technical Reports Server (NTRS)

    Espejo, R.; Torrent, J.; Roquero, C.

    1973-01-01

    The application or ERTS-1 data to determine the major river bed changes of the Ebro River in northeastern Spain is discussed. Image quality was good enough to permit a clear identification of the river course and bands MSS 5 and 7 proved to be the most useful for this purpose. Reflectance for band 5 was high due to the high sediment content of the water and sufficed to identify the river. Features like bodies of water related to old channels and depressions were only apparent in band 7.

  20. Hydrobiological characteristics of Shark River estuary, Everglades National Park, Florida

    USGS Publications Warehouse

    McPherson, B.F.

    1970-01-01

    Water quality in the Shark River estuary was strongly influenced by seasonal patterns of rainfall, water level and temperature. During the rainy season (summer and early fall) the salinity in the 20-mile long estuary ranged from that of fresh water to half that of sea water while concentrations of dissolved oxygen were low, 2-5 milligrams per liter (mg/l) presumably because, among other factors, microbial activity and respiration were accelerated by high temperatures (30-33 degrees C). During the dry season (late fall through spring) the salinity ranged from 18 grams per liter (g/l) in the headwaters to 36 g/l at the Gulf during a dry year such as 1967 and from 1 to 25 g/l during a wet year such as 1969. Concentrations of dissolved oxygen increased from 2-3 mg/l in the summer of 1967 to 4-7 mg/l in the winter of 1968, and temperature decreased from an average of about 30 degrees C in summer to 20 degrees C in winter. Water level declined 5 to 10 decimeters in the headwaters during the dry season, and salinity and tidal action increased. Large amounts of submerged vegetation died in some headwater creeks at the end of the dry season, presumably killed by salinities above 3 g/l. The decaying organic matter and the decrease in photosynthesis resulted in low dissolved oxygen (1-2 mg/l). Fish died at this time probably as a result of the low dissolved oxygen. Trace elements, heavy metals and insecticides occurred in the waters of the estuary in concentrations below those indicated as harmful for aquatic life by current standards established by the Federal Water Pollution Control Administration (1968). The insecticides detected were concentrated in sediment and in various organisms. The patterns of distribution of planktonic and small nektonic animals in the estuary were related to salinity. Copepods (Arcatia tonsa, Labidocera aestiva, Pseudodiaptomus coronatus), cumaceans (Cyclaspis sp.), chaetognaths (Sagitta hispida), bay anchovies (Anchoa mitchilli), and scaled

  1. Physical, hydrological, and biological characteristics of the Loxahatchee River estuary, Florida

    USGS Publications Warehouse

    McPherson, Benjamin F.; Sabanskas, Maryann; Long, William Atwood

    1982-01-01

    The Loxahatchee River estuary in southeast Florida has periodically closed and opened to the sea as a result of natural causes. In the last 30 years, the estuary has remained open only by dredging. Activities of man in the estuary and basin affect freshwater and tidal flow which in turn affect bathymetry, bottom sediment, and biota. Under present conditions, tidal flow is much larger than freshwater inflow. (USGS)

  2. Research, Monitoring, and Evaluation for the Federal Columbia River Estuary Program

    SciTech Connect

    Johnson, Gary E.; Diefenderfer, Heida L.; Ebberts, Blaine D.; Tortorici, Cathy; Yerxa, Tracey; Leary, J.; Skalski, John R.

    2008-02-05

    The purpose ofthis document is to describe research, monitoring, and evaluation (RME) for the Federal Columbia River Estuary Program. The intent of this RME effort is to provide data and information to evaluate progress toward meeting program goals and objectives and support decision-making in the Estuary Program. The goal of the Estuary Program is to understand, conserve, and restore the estuary ecosystem to improve the performance of listed salmonid populations. The Estuary Program has five general objectives, designed to fulfill the program goal, as follows. 1. Understand the primary stressors affecting ecosystem controlling factors, such as ocean conditions and invasive species. 2. Conserve and restore factors controlling ecosystem structures and processes, such as hydrodynamics and water quality. 3. Increase the quantity and quality of ecosystem structures, i.e., habitats, juvenile salmonids use during migration through the estuary. 4. Maintain the food web to benefit salmonid performance. 5. Improve salmonid performance in terms of life history diversity, foraging success, growth, and survival. The goal of estuary RME is to provide pertinent and timely research and monitoring information to planners, implementers, and managers of the Estuary Program. In conclusion, the estuary RME effort is designed to meet the research and monitoring needs of the estuary Program using an adaptive management process. Estuary RME's success and usefulness will depend on the actual conduct of adaptive management, as embodied in the objectives, implrementation, data, reporting, and synthesis, evaluation, and decision-making described herein.

  3. Environmental assessment of pesticides in the Mondego River Estuary (Portugal).

    PubMed

    Cruzeiro, Catarina; Rocha, Eduardo; Pardal, Miguel Ângelo; Rocha, Maria João

    2016-02-15

    The Mondego River estuary, located on the North Atlantic Ocean Ecoregion, is a basin affected by agricultural run-off with increasing signs of eutrophication. We evaluated the amounts and distribution of 56 priority pesticides belonging to distinct categories (insecticides, herbicides and fungicides). Temporal trends were considered and a total of 42 surface water samples were collected between 2010 and 2011. More than 55% of the GC-MS/MS-quantified pesticides were above the maximum amounts established by the European Directives (98/83/EC and 2013/39/EU). Based on the concentration addition (CA) and independent action (IA) models, we used a two-tiered approach to assess the hazard of the pesticide mixture, at the maximum concentration found, reflecting a potential risk. Short-term exposure using Artemia salina indicated a significant toxic effect where the locomotion of the animals was clearly affected. PMID:26763320

  4. Hydrodynamic and Salinity Intrusion Model in Selangor River Estuary

    NASA Astrophysics Data System (ADS)

    Haron, N. F.; Tahir, W.

    2016-07-01

    A multi-dimensional hydrodynamic and transport model has been used to develop the hydrodynamic and salinity intrusion model for Selangor River Estuary. Delft3D-FLOW was applied to the study area using a curvilinear, boundary fitted grid. External boundary forces included ocean water level, salinity, and stream flow. The hydrodynamic and salinity transport used for the simulation was calibrated and confirmed using data on November 2005 and from May to June 2014. A 13-day period for November 2005 data and a 6-day period of May to June 2014 data were chosen as the calibration and confirmation period because of the availability of data from the field-monitoring program conducted. From the calibration results, it shows that the model was well suited to predict the hydrodynamic and salinity intrusion characteristics of the study area.

  5. Comparison of common persistent organic pollutants (POPs) in flounder (Platichthys flesus) from the Vistula (Poland) and Douro (Portugal) River estuaries.

    PubMed

    Waszak, Ilona; Dabrowska, Henryka; Komar-Szymczak, Katarzyna

    2014-04-15

    Groups of flounder (Platichthys flesus) females were collected in 2011 from the Vistula River and the Duoro River estuaries and corresponding reference sites in the southern Baltic Sea and Portuguese coast of the Atlantic Ocean to measure and compare the levels and profiles of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), and polybrominated diphenyl ethers (PBDEs). The estuaries' sediments were also investigated. Several differences were found in the POPs between the estuaries and between the two marine regions, which were highlighted by PCA. The Vistula River estuary POPs, significantly higher than in the Douro River estuary, were dominated by DDTs followed by PCBs. PBDEs levels, indifferent between the estuaries, were relatively low. The POP levels in flounder and sediment evaluated against environmental assessment criteria (EACs) indicated that none of the measured contaminants for which EAC had been established exceeded the criterion, except for CB-118 in flounder from the Vistula River estuary. PMID:24492155

  6. Circulation and physical processes within the San Gabriel River Estuary during summer 2005

    USGS Publications Warehouse

    Rosenberger, Kurt J.; Xu, Jingping; Stein, Eric D.; Noble, Marlene A.; Gartner, Anne L.

    2007-01-01

    The Southern California Coastal Water Research Project (SCCWRP) is developing a hydrodynamic model of the SGR estuary, which is part of the comprehensive water-quality model of the SGR estuary and watershed investigated by SCCWRP and other local agencies. The hydrodynamic model will help understanding of 1) the exchange processes between the estuary and coastal ocean; 2) the circulation patterns in the estuary; 3) upstream natural runoff and the cooling discharge from PGS. Like all models, the SGR hydrodynamic model is only useful after it is fully calibrated and validated. In May 2005, SCCWRP requested the assistance of the U.S. geological Survey (USGS) Coastal and Marine Geology team (CMG) in collecting data on the hydrodynamic conditions in the estuary during the summer dry season. The summer was chosen for field data collection as this was assumed to be the season with the greatest potential for chronic degraded water quality due to low river flow and high thermal stratification within the estuary (due to both higher average air temperature and PGS output). Water quality can be degraded in winter as well, when higher river discharge events bring large volumes of water from the Los Angeles basin into the estuary. The objectives of this project were to 1) collect hydrodynamic data along the SGR estuary; 2) study exchange processes within the estuary through analysis of the hydrodynamic data; and 3) provide field data for model calibration and validation. As the data only exist for the summer season, the results herein only apply to summer conditions.

  7. Numerical model of the salt-wedge reach of the Duwamish River estuary, King County, Washington

    USGS Publications Warehouse

    Prych, Edmund A.; Haushild, W.L.; Stoner, J.D.

    1976-01-01

    A numerical model of a salt-wedge estuary developed by Fischer (1974) has been expanded and used to calculate the distributions of salinity, temperature, chlorophyll a concentration, biochemical oxygen demand, and dissolved-oxygen concentration in the Duwamish River estuary, King County, Wash. The model was used to predict the dissolved-oxygen concentrations in the Duwamish River estuary when the Renton Treatment Plant sewage-effluent discharge is increased to its proposed maximum of 223 cubic feet per second. The computed monthly average dissolved-oxygen concentrations in the estuary decreased by a maximum of 2 milligrams per liter when compared with computations for the summer of 1971, when the effluent discharge averaged 37 cubic feet per second. The increase in effluent discharge is not expected to cause large changes in phytoplankton concentrations in the estuary. (Woodard-USGS)

  8. Concentrations, loads, and sources of polychlorinated biphenyls, Neponset River and Neponset River Estuary, eastern Massachusetts

    USGS Publications Warehouse

    Breault, Robert F.

    2011-01-01

    Polychlorinated biphenyls (PCBs) are known to contaminate the Neponset River, which flows through parts of Boston, Massachusetts, and empties into the Neponset River Estuary, an important fish-spawning area. The river is dammed and impassable to fish. The U.S. Geological Survey, in cooperation with the Massachusetts Department of Fish and Game, Division of Ecological Restoration, Riverways Program, collected, analyzed, and interpreted PCB data from bottom-sediment, water, and (or) fish-tissue samples in 2002, 2004-2006. Samples from the Neponset River and Neponset River Estuary were analyzed for 209 PCB congeners, PCB homologs, and Aroclors. In order to better assess the overall health quality of river-bottom sediments, sediment samples were also tested for concentrations of 31 elements. PCB concentrations measured in the top layers of bottom sediment ranged from 28 nanograms per gram (ng/g) just upstream of the Mother Brook confluence to 24,900 ng/g measured in Mother Brook. Concentrations of elements in bottom sediment were generally higher than background concentrations and higher than levels considered toxic to benthic organisms according to freshwater sediment-quality guidelines defined by the U.S. Environmental Protection Agency. Concentrations of dissolved PCBs in water samples collected from the Neponset River (May 13, 2005 to April 28, 2006) averaged about 9.2 nanograms per liter (ng/L) (annual average of monthly values); however, during the months of August (about 16.5 ng/L) and September (about 15.6 ng/L), dissolved PCB concentrations were greater than 14 ng/L, the U.S. Environmental Protection Agency's freshwater continuous chronic criterion for aquatic organisms. Concentrations of PCBs in white sucker (fillets and whole fish) were all greater than 2,000 ng/g wet wt, the U.S. Environmental Protection Agency's guideline for safe consumption of fish: PCB concentrations measured in fish-tissue samples collected from the Tileston and Hollingsworth and

  9. Horizontal distribution and population dynamics of the dominant mysid Hyperacanthomysis longirostris along a temperate macrotidal estuary (Chikugo River estuary, Japan)

    NASA Astrophysics Data System (ADS)

    Suzuki, Keita W.; Nakayama, Kouji; Tanaka, Masaru

    2009-08-01

    The estuarine turbidity maximum (ETM) that develops in the lower salinity areas of macrotidal estuaries has been considered as an important nursery for many fish species. Mysids are one of the dominant organisms in the ETM, serving as a key food source for juvenile fish. To investigate the horizontal distribution and population dynamics of dominant mysids in relation to the fluctuation of physical conditions (temperature, salinity, turbidity, and freshwater discharge), we conducted monthly sampling (hauls of a ring net in the surface water) along the macrotidal Chikugo River estuary in Japan from May 2005 to December 2006. Hyperacanthomysis longirostris was the dominant mysid in the estuary, usually showing peaks of density and biomass in or close to the ETM (salinity 1-10). In addition, intra-specific differences (life-cycle stage, sex, and size) in horizontal distribution were found along the estuary. Larger males and females, particularly gravid females, were distributed upstream from the center of distribution where juveniles were overwhelmingly dominant. Juveniles increased in size toward the sea in marked contrast with males and females. The findings suggest a possible system of population maintenance within the estuary; gravid females release juveniles in the upper estuary, juveniles grow during downstream transport, young males and females mature during the upstream migration. Density and biomass were primarily controlled by seasonal changes of temperature, being high at intermediate temperatures (ca. 15-25 °C in late spring and fall) and being low at the extreme temperatures (ca. 10 °C in midwinter and 30 °C in midsummer). High density (up to 666 ind. m -3) and biomass (up to 168 mg dry weight m -3) of H. longirostris were considered to be comparable with those of copepods in the estuary.

  10. Geomorphologic and physical characteristics of a human impacted estuary: Quequén Grande River Estuary, Argentina

    NASA Astrophysics Data System (ADS)

    Perillo, Gerardo M. E.; Pérez, Daniel E.; Piccolo, M. Cintia; Palma, Elbio D.; Cuadrado, Diana G.

    2005-01-01

    Even though the Quequén Grande River Estuary has economic and strategic importance from an oceanographic point of view, it has been ignored until recently. Nevertheless, many anthropogenic modifications (i.e., dredging, jetty and harbour construction, etc.) have taken place in the last 100 years which, most of them, have resulted in significative economic expenses to the harbour and city authorities due to the lack of adequate prior studies. The purpose of this article is to provide a review of the present status of the geomorphology and main physical characteristics of the estuary and describe the effects of these man-made modifications upon the estuary. Data were gathered in several field cruises from 1994 to 2000 plus from continuous recording devices installed at or near the estuary directed to define the present geomorphologic and oceanographic conditions of the estuary and to establish a monitoring program. The ultimate goal is to provide some practical solutions in diminishing the maintenance of the harbour and to provide pollution-control devices. The estuary is classified as a microtidal, primary, coastal-plain system. It can be considered as a partly-mixed system 2 km from the mouth up to its head (15 km inland). Artificial dredging to accommodate the Quequén harbour in the last 2 km of the estuary has induced a highly stratified water column where the upper 2-3 m concentrates low salinity water and the lower layer is filled by water of the same or slightly higher salinity than the inner shelf waters. Due to the presence of a step at the head of the harbour, water circulation is very reduced and in some cases nonexistent, producing strong reductive and even anoxic conditions. The foot of the step is a sediment and organic matter trap that must be dredged periodically to insure adequate navigability.

  11. Impact of the Clean Water Act on the levels of toxic metals in urban estuaries: The Hudson River estuary revisited

    SciTech Connect

    Sanudo-Wilhelmy, S.A.; Gill, G.A.

    1999-10-15

    To establish the impact of the Clean Water Act on the water quality of urban estuaries, dissolved trace metals and phosphate concentrations were determined in surface waters collected along the Hudson River estuary between 1995 and 1997 and compared with samples collected in the mid-1970s by Klinkhammer and Bender. The median concentrations along the estuary have apparently declined 36--56% for Cu, 55--89% for Cd, 53--85% for Ni, and 53--90% for Zn over a period of 23 years. These reductions appear to reflect improvements in controlling discharges from municipal and industrial wastewater treatment plants since the Clean Water Act was enacted in 1972. In contrast, levels of dissolved nutrients (PO{sub 4}) have remained relatively constant during the same period of time, suggesting that wastewater treatment plant improvements in the New York/New Jersey Metropolitan area have not been as effective at reducing nutrient levels within the estuary. While more advanced wastewater treatment could potentially reduce the levels of Ag and PO{sub 4} along the estuary, these improvements would have a more limited effect on the levels of other trace metals.

  12. Climate change drives warming in the Hudson River Estuary, New York (USA).

    PubMed

    Seekell, David A; Pace, Michael L

    2011-08-01

    Estuaries may be subject to warming due to global climate change but few studies have considered the drivers or seasonality of warming empirically. We analyzed temperature trends and rates of temperature change over time for the Hudson River estuary using long-term data, mainly from daily measures taken at the Poughkeepsie Water Treatment Facility. This temperature record is among the longest in the world for a river or estuary. The Hudson River has warmed 0.945 °C since 1946. Many of the warmest years in the record occurred in the last 16 years. A seasonal analysis of trends indicated significant warming for the months of April through August. The warming of the Hudson is primarily related to increasing air temperature. Increasing freshwater discharge into the estuary has not mitigated the warming trend. PMID:21720614

  13. Freshwater runoff and salinity distribution in the Loxahatchee River estuary, southeastern Florida, 1980-82

    USGS Publications Warehouse

    Russell, G.M.; McPherson, B.F.

    1984-01-01

    Freshwater mixed with seawater over a distance of 5 to 10 river miles in the Loxahatchee River estuary during a recent study. Large freshwater inflows vertically stratified the estuary and shifted the mixing zone seaward. In the northwest fork of the estuary, the saltwater-freshwater interface moved daily about 0.5 to 1.5 river miles as a result of tides, and annually about 3 to 5 miles as a result of seasonal changes in freshwater inflow. In the southwest fork, saltwater movement upstream was blocked by a gate and dam structure in Canal-18, 4.7 miles upstream from the Atlantic Ocean. Although Canal-18 discharged about one-third of the total freshwater tributary inflow to the estuary, the effects of canal discharge on salinity were limited to relatively brief periods. Much of the time, no freshwater was discharged. (USGS)

  14. Response of the turbidity maximum zone to fluctuations in sediment discharge from river to estuary in the Changjiang Estuary (China)

    NASA Astrophysics Data System (ADS)

    Jiang, Xuezhong; Lu, Bing; He, Yuhong

    2013-10-01

    In the Changjiang Estuary, interactions between the sea and the river result in the development of a turbidity maximum zone (TMZ). Riverine sediments are an important source for TMZ formation. Since the 1960s, sediment discharge from the river basin to the estuary has decreased due to dam construction, water and soil conservation, and water diversion projects. Thirty-two Landsat images of the estuary, covering the period from 1979 to 2008, were collected to identify the TMZ response to sediment decline. A threshold value of suspended sediment concentration (SSC) of 0.7 kg/m3, corresponding to a spectrum reflectance of 5% of Landsat MSS band 7 and 7% of Landsat TM/ETM band 4, was used to identify the Changjiang Estuary TMZ. The TMZ area was then extracted from each image to investigate its temporal and spatial variations during the past 30 years. The images were grouped into five time series; the average TMZ area of each series was estimated. The results show that the TMZ area declined 23% from series (a) to series (e), responding to a 77% reduction in riverine sediment discharge. In addition, the TMZ had strong seasonal and tidal variations; it was generally larger during flood seasons than during dry seasons and during spring tides compared to neap tides. The spring/neap tidal cycle played a more important role in TMZ change than did the seasonal cycle. Due to the continued reduction of sediment discharge to the estuary resulting from dams already constructed and to those that will be constructed upstream in the Changjiang River, it is predicted that the TMZ area will continue decreasing and that the re-suspension of local sediments will play a more important role in the formation of the TMZ.

  15. Modeling tidal circulation and stratification in Skagit River estuary using an unstructured grid ocean model

    NASA Astrophysics Data System (ADS)

    Yang, Zhaoqing; Khangaonkar, Tarang

    Tidal circulation and river plume dynamics in shallow-water estuarine systems with large intertidal zones are complex. Strong asymmetries in tidal currents and stratification often occur in the intertidal zones and subtidal channels over a tidal cycle. The Skagit River is the largest estuary with respect to the discharge of a significant amount of freshwater and sediment into Puget Sound, Washington. It consists of a large intertidal zone with multiple tidal channels near the mouth of the estuary. To simulate the tidal circulation and salinity stratification accurately in the intertidal region, an unstructured grid numerical model with wetting-drying capability and the capability to accurately represent the bathymetry of tidal flats and the geometry of shallow distributary channels is necessary. In this paper, a modeling study for the Skagit River estuary using a three-dimensional unstructured grid, finite-volume coastal ocean model (FVCOM) supported by high-resolution LIDAR data is presented. The hydrodynamic model was validated with observed water surface elevation, velocity, and salinity data over spring and neap tidal cycles under low-river-flow and high-river-flow conditions. Wetting and drying processes in the intertidal zone and strong stratification in the estuary were simulated successfully by the model. Model results indicate that the Skagit River estuary is a highly stratified estuary, but destratification can occur during flood tide. Tides and baroclinic motion are the dominant forcing in the Skagit River estuary, but strong wind events can affect the currents in the intertidal zone significantly. Preliminary analysis also indicated that the salinity intrusion length scale is proportional to the river flow to the -¼ power.

  16. Sea-floor character and geology off the entrance to the Connecticut River, northeastern Long Island Sound

    USGS Publications Warehouse

    Poppe, Lawrence J.; McMullen, Katherine Y.; Ackerman, Seth D.; Guberski, Megan R.; Wood, Douglas A.

    2013-01-01

    Datasets of gridded multibeam bathymetry and sidescan-sonar backscatter, together covering approximately 29.1 square kilometers, were used to interpret character and geology of the sea floor off the entrance to the Connecticut River in northeastern Long Island Sound. Although originally collected for charting purposes during National Oceanic and Atmospheric Administration hydrographic survey H12013, these acoustic data, sidescan-sonar imagery, and the sea-floor sampling and photography stations subsequently occupied to verify the acoustic data (1) show the composition and terrain of the seabed, (2) provide information on sediment transport and benthic habitat, and (3) are part of an expanding series of studies that provide a fundamental framework for research and resource management (for example, cables, pipelines, and dredging) activities in this major east coast estuary.

  17. Pu and 137Cs in the Yangtze River estuary sediments: distribution and source identification.

    PubMed

    Liu, Zhiyong; Zheng, Jian; Pan, Shaoming; Dong, Wei; Yamada, Masatoshi; Aono, Tatsuo; Guo, Qiuju

    2011-03-01

    Pu isotopes and (137)Cs were analyzed using sector field ICP-MS and γ spectrometry, respectively, in surface sediment and core sediment samples from the Yangtze River estuary. (239+240)Pu activity and (240)Pu/(239)Pu atom ratios (>0.18) shows a generally increasing trend from land to sea and from north to south in the estuary. This spatial distribution pattern indicates that the Pacific Proving Grounds (PPG) source Pu transported by ocean currents was intensively scavenged into the suspended sediment under favorable conditions, and mixed with riverine sediment as the water circulated in the estuary. This process is the main control for the distribution of Pu in the estuary. Moreover, Pu is also an important indicator for monitoring the changes of environmental radioactivity in the estuary as the river basin is currently the site of extensive human activities and the sea level is rising because of global climate changes. For core sediment samples the maximum peak of (239+240)Pu activity was observed at a depth of 172 cm. The sedimentation rate was estimated on the basis of the Pu maximum deposition peak in 1963-1964 to be 4.1 cm/a. The contributions of the PPG close-in fallout Pu (44%) and the riverine Pu (45%) in Yangtze River estuary sediments are equally important for the total Pu deposition in the estuary, which challenges the current hypothesis that the riverine Pu input was the major source of Pu budget in this area. PMID:21306104

  18. Research, Monitoring, and Evaluation for the Federal Columbia River Estuary Program.

    SciTech Connect

    Johnson, Gary E.; Diefenderfer, Heida L.

    2008-02-20

    The purpose of this document is to describe research, monitoring, and evaluation (RME) for the Federal Columbia River Estuary Program, hereafter called 'the Estuary Program'. The intent of this RME effort is to provide data and information to evaluate progress toward meeting program goals and objectives and support decision making in the Estuary Program. The goal of the Estuary Program is to understand, conserve, and restore the estuary ecosystem to improve the performance of listed salmonid populations. The Estuary Program has five general objectives, designed to fulfill the program goal, as follows: (1) Understand the primary stressors affecting ecosystem controlling factors, such as ocean conditions and invasive species. (2) Conserve and restore factors controlling ecosystem structures and processes, such as hydrodynamics and water quality. (3) Increase the quantity and quality of ecosystem structures, i.e., habitats, juvenile salmonids use during migration through the estuary. (4) Maintain the food web to benefit salmonid performance. (5) Improve salmonid performance in terms of life history diversity, foraging success, growth, and survival. The goal of estuary RME is to provide pertinent and timely research and monitoring information to planners, implementers, and managers of the Estuary Program. The goal leads to three primary management questions pertaining to the main focus of the Estuary Program: estuary habitat conservation and restoration. (1) Are the estuary habitat actions achieving the expected biological and environmental performance targets? (2) Are the offsite habitat actions in the estuary improving juvenile salmonid performance and which actions are most effective at addressing the limiting factors preventing achievement of habitat, fish, or wildlife performance objectives? (3) What are the limiting factors or threats in the estuary/ocean preventing the achievement of desired habitat or fish performance objectives? Performance measures for the

  19. Embryotoxicity and genotoxicity evaluation of sediments from Yangtze River estuary using zebrafish (Danio rerio) embryos.

    PubMed

    Li, Qian; Chen, Ling; Liu, Li; Wu, Lingling

    2016-03-01

    Sediments function both as a sink and a source of pollutants in aquatic ecosystems and may impose serious effects on benthic organisms and human health. As one of the largest estuaries in the world, the Yangtze River estuary suffers from abundant wastewater from the coastal cities. In this study, the zebrafish (Danio rerio) embryos were employed in the fish embryo test and a comet assay to evaluate the embryotoxicity and genotoxicity of the sediments from the Yangtze River estuary, respectively. Results showed that the sediments from the Yangtze River estuary significantly increased mortality, induced development abnormalities, and reduced hatching rate and heart rate of zebrafish embryos after 96 h of exposure. Significant genotoxicity was observed in the samples relative to the controls. Relatively low-level embryotoxicity and genotoxicity of sediments were found in the Yangtze River compared with other river systems. Toxic responses were also discussed in relation to the analyzed organic contaminants in sediments. More attention should be paid to non-priority pollutant monitoring in the Yangtze River estuary. PMID:26545894

  20. From headwaters to coast: influence of human activities on water quality of the Potomac River Estuary

    USGS Publications Warehouse

    Bricker, Suzanne B.; Rice, Karen C.; Bricker, Owen P., III

    2014-01-01

    The natural aging process of Chesapeake Bay and its tributary estuaries has been accelerated by human activities around the shoreline and within the watershed, increasing sediment and nutrient loads delivered to the bay. Riverine nutrients cause algal growth in the bay leading to reductions in light penetration with consequent declines in sea grass growth, smothering of bottom-dwelling organisms, and decreases in bottom-water dissolved oxygen as algal blooms decay. Historically, bay waters were filtered by oysters, but declines in oyster populations from overfishing and disease have led to higher concentrations of fine-sediment particles and phytoplankton in the water column. Assessments of water and biological resource quality in Chesapeake Bay and tributaries, such as the Potomac River, show a continual degraded state. In this paper, we pay tribute to Owen Bricker’s comprehensive, holistic scientific perspective using an approach that examines the connection between watershed and estuary. We evaluated nitrogen inputs from Potomac River headwaters, nutrient-related conditions within the estuary, and considered the use of shellfish aquaculture as an in-the-water nutrient management measure. Data from headwaters, nontidal, and estuarine portions of the Potomac River watershed and estuary were analyzed to examine the contribution from different parts of the watershed to total nitrogen loads to the estuary. An eutrophication model was applied to these data to evaluate eutrophication status and changes since the early 1990s and for comparison to regional and national conditions. A farm-scale aquaculture model was applied and results scaled to the estuary to determine the potential for shellfish (oyster) aquaculture to mediate eutrophication impacts. Results showed that (1) the contribution to nitrogen loads from headwater streams is small (about 2 %) of total inputs to the Potomac River Estuary; (2) eutrophic conditions in the Potomac River Estuary have improved in

  1. Proceedings of the Columbia River Estuary Conference on Ecosystem Restoration.

    SciTech Connect

    U.S. Bonneville Power Administration

    2008-08-01

    The 2008 Columbia River Estuary Conference was held at the Liberty Theater in Astoria, Oregon, on April 19-20. The conference theme was ecosystem restoration. The purpose of the conference was to exchange data and information among researchers, policy-makers, and the public, i.e., interrelate science with management. Conference organizers invited presentations synthesizing material on Restoration Planning and Implementation (Session 1), Research to Reduce Restoration Uncertainties (Session 2), Wetlands and Flood Management (Session 3), Action Effectiveness Monitoring (Session 4), and Management Perspectives (Session 5). A series of three plenary talks opened the conference. Facilitated speaker and audience discussion periods were held at the end of each session. Contributed posters conveyed additional data and information. These proceedings include abstracts and notes documenting questions from the audience and clarifying answers from the presenter for each talk. The proceedings also document key points from the discussion periods at the end of each session. The conference program is outlined in the agenda section. Speaker biographies are presented in Appendix A. Poster titles and authors are listed in Appendix B. A list of conference attendees is contained in Appendix C.

  2. Cruise observation and numerical modeling of turbulent mixing in the Pearl River estuary in summer

    NASA Astrophysics Data System (ADS)

    Pan, Jiayi; Gu, Yanzhen

    2016-06-01

    The turbulent mixing in the Pearl River estuary and plume area is analyzed by using cruise data and simulation results of the Regional Ocean Model System (ROMS). The cruise observations reveal that strong mixing appeared in the bottom layer on larger ebb in the estuary. Modeling simulations are consistent with the observation results, and suggest that inside the estuary and in the near-shore water, the mixing is stronger on ebb than on flood. The mixing generation mechanism analysis based on modeling data reveals that bottom stress is responsible for the generation of turbulence in the estuary, for the re-circulating plume area, internal shear instability plays an important role in the mixing, and wind may induce the surface mixing in the plume far-field. The estuary mixing is controlled by the tidal strength, and in the re-circulating plume bulge, the wind stirring may reinforce the internal shear instability mixing.

  3. Comparing spatial and temporal dynamics of anammox and denitrifying communities at Cape Fear River Estuary and New River Estuary, North Carolina

    NASA Astrophysics Data System (ADS)

    Lisa, J. A.; Hirsch, M. D.; Duernberger, K. A.; Tobias, C. R.; Song, B.

    2010-12-01

    Anaerobic ammonium oxidation (anammox) and denitrification are two main microbial processes capable of removing fixed nitrogen by conversion into a gaseous species. Both microbial processes are known to occur in anoxic estuarine sediments and are capable of remediating excess nitrogen loadings from anthropogenic activities. In order to understand the importance of anammox and denitrification in estuarine ecosystems, we investigated both processes in two different estuaries of North Carolina to compare sedimentary nitrogen removal capacity and to identify key players of N2 production pathways. Both Cape Fear River Estuary (CFRE) and New River Estuary (NRE) are highly enriched with nitrogen from anthropogenic sources in spite of distinct geomorphological and geochemical characteristics. We conducted seasonal samplings to collect sediments across transects at fifteen stations along each estuary. 15N tracer techniques were used to measure spatial and temporal variations of N2 production by denitrification and anammox in estuarine sediments. Molecular analysis of nitrous oxide reductase (nosZ) and hydrazine oxidase (hzo) genes was conducted to examine community structures of denitrifying and anammox bacteria, respectively. Denitrification was found to be the dominant N2 production processes in both estuaries. Anammox contributed up to 19% and 15 % of total N2 productions in the CFEE and the NRE, respectively. Phylogenetic analysis of hzo genes identified that the anammox bacteria at both estuaries are closely associated with five known genera in the order Brocadiales. Anammox communities at the CFRE showed biogeographical distribution along the estuarine gradients while high seasonal variations were observed in the NRE communities. Spatial and temporal variations of denitrifying communities at both estuaries were also found based on nosZ gene analysis. Multivariate analysis was conducted to define key biogeochemical parameters influencing the community dynamics and

  4. Quaternary landscape evolution of the Turkey River Valley, northeastern Iowa

    SciTech Connect

    Hudak, C.M.

    1987-01-01

    The Turkey River Valley, a major Mississippi tributary in northeastern Iowa, provides a more complete and accessible Quaternary record than the Upper Mississippi Valley. This project, using 3-dimensional reconstructions of both valley and upland deposits, revealed at least 13 important depositional, erosional, and soil-forming events. From oldest to youngest these events are: (1) deposition of pre-Illinoian till; (2) erosion of till and bedrock as the Turkey River cut down; (3) deposition of fluvial and colluvial sediments in the valley; (4) development of a Sangamon soil(s) on both the pre-Illinoian (upland) till and valley sediments; (5) truncation of the Sangamon soil(s) relatively high in the valley as bedrock entrenchment proceeded to its deepest point; (6) deposition of coarse fluvial and colluvial sediments in the valley prior to 32,000 yr. B.P.; (7) aggradation of mostly loess-derived alluvium until approximately 16,000 yr. B.P.; (8) large-scale colluviation between approximately 32,000 and 13,000 yr., B.P.; (9) major downcutting between 16,000 and 14,000 yr. B.P.; (10) aggradation of coarse to medium alluvium from approximately 14,000 to 13,000 yr. B.P.; (11) overall downcutting during several intervals of the late Wisconsinan and early Holocene; (12) aggradation of mid to late Holocene alluvium starting by 5000 yr. B.P.; (13) lateral erosion and deposition during the past 200 yr. B.P. Turkey River Valley deposits previously interpreted as pre-Illinoian are now recognized as late Wisconsinan or early Holocene, as indicated by /sup 14/C dates and molluscan fossils. The Paleozoic Plateau landform region (formerly part of the Driftless Area) is herein interpreted as a rugged, although complex, extension of the Iowan Erosion Surface.

  5. Sediment trapping by haloclines of a river plume in the Pearl River Estuary

    NASA Astrophysics Data System (ADS)

    Ren, Jie; Wu, Jiaxue

    2014-07-01

    Sediment trapping by the halocline of a river plume was investigated over a spring-neap tidal cycle in the 2010 dry season in the Pearl River Estuary. Benthic tripod observations and concurrent shipboard measurements were conducted to examine mean and turbulent flows, and sediment distributions. The field observations showed that suspended particles are apparently concentrated on the halocline of the river plume, forming a patchy high-concentration suspension with larger floc sizes. This sediment trapping occurred only on the neap tide when the estuary was highly stratified. An estimation of the gradient Richardson number indicates that stratification suppression is dominant below the halocline, whereas shear-induced instability occurs above the halocline. The turbulent kinetic energy balance demonstrates that the buoyancy flux dominates over viscous dissipation in turbulence destruction. Therefore, the trapping of suspended sediment with large floc sizes on the halocline is induced by both salinity stratification and buoyancy-induced instability. This finding can explain the role of salinity stratification in the mechanism for estuarine turbidity maxima and long-distance transportation of suspended sediment.

  6. Sediment transport due to extreme events: The Hudson River estuary after tropical storms Irene and Lee

    NASA Astrophysics Data System (ADS)

    Ralston, David K.; Warner, John C.; Geyer, W. Rockwell; Wall, Gary R.

    2013-10-01

    Storms Irene and Lee in 2011 produced intense precipitation and flooding in the U.S. Northeast, including the Hudson River watershed. Sediment input to the Hudson River was approximately 2.7 megaton, about 5 times the long-term annual average. Rather than the common assumption that sediment is predominantly trapped in the estuary, observations and model results indicate that approximately two thirds of the new sediment remained trapped in the tidal freshwater river more than 1 month after the storms and only about one fifth of the new sediment reached the saline estuary. High sediment concentrations were observed in the estuary, but the model results suggest that this was predominantly due to remobilization of bed sediment. Spatially localized deposits of new and remobilized sediment were consistent with longer term depositional records. The results indicate that tidal rivers can intercept (at least temporarily) delivery of terrigenous sediment to the marine environment during major flow events.

  7. Spatial dynamics of biogeochemical processes in the St. Louis River freshwater estuary

    EPA Science Inventory

    In the Great Lakes, river-lake transition zones within freshwater estuaries are hydrologically and biogeochemically dynamic areas that regulate nutrient and energy fluxes between rivers and Great Lakes. The goal of our study was to characterize the biogeochemical properties of th...

  8. Physical, Hydrological, and Biological Characteristics of the Loxahatchee River Estuary, Florida

    USGS Publications Warehouse

    McPherson, Benjamin F.; Sabanskas, Maryann; Long, William A.

    1982-01-01

    The Loxahatchee River estuary empties into the Atlantic Ocean at Jupiter Inlet in southeastern Florida. Although relatively small, the estuary is important for its esthetic value and for its sport fishing, boating, recreation, tourism, and prime residential development. In recent years, the condition of the estuary has become of concern to many citizens and agencies of the State. In response to this concern, the U.S. Geological Survey planned and carried out an in-depth environmental investigation. The events that led to the investigation and the objectives of the investigation are outlined in a recent U.S. Geological Survey report by McPherson and Sabanskas (WRI 80-1109).

  9. Seasonal variation of tidal prism and energy in the Changjiang River estuary: a numerical study

    NASA Astrophysics Data System (ADS)

    Zhang, Min; Townend, Ian Howard; Cai, Huayang; Zhou, Yunxuan

    2016-01-01

    Tidal rivers are intrinsically complex because tidal propagation is influenced by river discharge. This study aims to examine the seasonal variation of tidal prism and energy variance in the tidal river of the Changjiang (Yangtze) River estuary in China. In order to quantify the behaviour of river and tide, we use numerical modelling that has been validated using measured data. We conduct our analysis by quantifying the discharge and energy variance in separate components for both the river and the tide, during wet and dry seasons. We note various definitions of tidal prism and explore the difference between tidal discharge on the flood and ebb and tidal storage volume. The results show that the river discharge attenuates the tidal motion and reduces the tidal flood discharge but the tidal storage volume is approximately constant with different riverine discharge since part of the fresh water discharge is intercepted and captured in the estuary due to the backwater effect. It appears that the tidal discharge adjusts according to the variation of river discharge to keep a constant tidal storage volume. An analysis of the hydraulics shows that the transition from tidal dominance (at the mouth) to river dominance (upstream) depends on the location of tidal current reversal which varies from wet season to dry season. Duringthe wet season, the Changjiang River estuary is totally dominated by energy from fresh water discharge.

  10. Decadal morphological evolution of the Yangtze Estuary in response to river input changes and estuarine engineering projects

    NASA Astrophysics Data System (ADS)

    Luan, Hua Long; Ding, Ping Xing; Wang, Zheng Bing; Ge, Jian Zhong; Yang, Shi Lun

    2016-07-01

    The Yangtze Estuary in China has been intensively influenced by human activities including altered river and sediment discharges in its catchment and local engineering projects in the estuary over the past half century. River sediment discharge has significantly decreased since the 1980s because of upstream dam construction and water-soil conservation. We analyzed bathymetric data from the Yangtze Estuary between 1958 and 2010 and divided the entire estuary into two sections: inner estuary and mouth bar area. The deposition and erosion pattern exhibited strong temporal and spatial variations. The inner estuary and mouth bar area underwent different changes. The inner estuary was altered from sedimentation to erosion primarily at an intermediate depth (5-15 m) along with river sediment decline. In contrast, the mouth bar area showed continued accretion throughout the study period. The frequent river floods during the 1990s and simultaneously decreasing river sediment probably induced the peak erosion of the inner estuary in 1986-1997. We conclude that both sediment discharge and river flood events played important roles in the decadal morphological evolution of the Yangtze Estuary. Regarding the dredged sediment, the highest net accretion rate occurred in the North Passage where jetties and groins were constructed to regulate the navigation channel in 1997-2010. In this period, the jetties induced enhanced deposition at the East Hengsha Mudflat and the high accretion rate within the mouth bar area was maintained. The impacts of estuarine engineering projects on morphological change extended beyond their sites.

  11. Microbial dissolved organic phosphorus utilization in the Hudson River Estuary

    SciTech Connect

    Ammerman, J.W. ); Angel, D.L. )

    1990-01-09

    The Hudson River Estuary has large inputs of phosphorus and other nutrients from sewage discharge. Concentrations of soluble reactive phosphorus (SRP) reach at least 4 uM during the summer low-flow period. Biological utilization of phosphorus and other nutrients is usually minimal because of the high turbidity and short residence time of the water. Therefore SRP is normally a conservative tracer of salinity, with maximum concentrations found off Manhattan and decreasing to the north. Despite this abundance of SRP, some components of the dissolved organic phosphorus (DOP) appear to be rapidly cycled by microbes. The objective of this study was to measure this DIP cycling during both the high- and low-flow periods. We measured the concentrations of SRP and DOP, the SRP turnover rate, algal and bacterial biomass, and the substrate turnover rates of two microbial cell-surface phosphatases, alkaline phosphatase (AP) and 5[prime] - nucleotidase (5PN). SRP concentrations ranged from about 0.5-4 uM, DOP was usually less than 1 uM. SRP and AP turnover were slow (generally < 5%/h), but 5PN substrate turnover was high with a median rate of 100%/h. Furthermore, over 30% of the phosphate hydrolyzed by 5PN was immediately taken up. If the nucleotide-P concentration is conservatively assumed to be 5 nM, than the rate of phosphate utilization from DOP is nearly equal to that from SRP. That is paradoxical considering the large SRP concentration, but suggests that much of this SRP may be biologically unavailable due to complexation with iron or other processes.

  12. Distribution and flux of /sup 226/Ra and /sup 228/Ra in the Amazon River estuary

    SciTech Connect

    Key, R.M.; Sarmiento, J.L.; Stallard, R.F.; Moore, W.S.

    1985-07-20

    Measurements of /sup 226/Ra and /sup 228/Ra in the Amazon River estuary show that desorption from riverborne suspended particulate matter in the estuary increases the riverine flux of both isotopes to the ocean by a factor of approximately 5 over the flux attributable to radium dissolved in the river water alone. The total Amazon flux supplies approximately 0.20% of the /sup 226/Ra and approximately 2.6% of the /sup 228/Ra standing crops in the near-surface Atlantic (0-200 m). Diffusive flux from estuarine and shelf sediments and desorption from resuspended sediments in the region of the estuary approximately double the estuarine /sup 226/Ra concentration and quadruple the estuarine /sup 228/Ra concentration above that caused by the dissolved and desorbed river components alone.

  13. DOWNSTREAM MIGRATION OF SALMONID SMOLTS IN OREGON RIVERS AND ESTUARIES

    EPA Science Inventory

    Migratory fish passage is an important designated use for many Oregon estuaries. Acoustic transmitters were implanted in coho smolts in 2004 and 2006 to evaluate how estuarine habitat, and habitat loss, might affect population health. Acoustic receivers that identified individu...

  14. Parasitological survey of mangrove oyster, Crassostrea rhizophorae, in the Pacoti River Estuary, Ceará State, Brazil.

    PubMed

    Sabry, Rachel Costa; Gesteira, Tereza Cristina Vasconcelos; Magalhães, Aimê Rachel Magenta; Barracco, Margherita Anna; Guertler, Cristhiane; Ferreira, Liana Pinho; Vianna, Rogério Tubino; da Silva, Patrícia Mirella

    2013-01-01

    The mangrove oyster, Crassostrea rhizophorae (Bivalvia, Ostreidae) is commonly collected by fisherwomen in the estuaries of the Ceará State (CE), Northeastern Brazil. Despite the socioeconomic importance of this natural resource, there are few studies on the health of the oysters in this region. This study aimed to survey pathological changes in the mangrove oyster C. rhizophorae in the estuary of the Pacoti River, CE. Adult oysters were collected in August 2008 (N=450) and December 2009 (N=450) at three sites of the Pacoti estuary and in 2010 (N=600) samplings were done quarterly at one site which has showed the higher prevalence de Perkinsus. Macroscopical and histological analyses were used to evaluate pathological changes, Ray's Fluid Thioglycollate Medium (RFTM) to detect Perkinsus spp. and polymerase chain reactions (PCR) and DNA sequencing to identify Perkinsus species. In 2009, RFTM assay detected Perkinsus sp. infecting the tissues of C. rhizophorae with low prevalences of 1.3%, 6.7% e 7.3% in sites 1, 2 and 3, respectively, and in 2010, in site 3, prevalence was 2% (12 of 600 oysters). PCR did not confirm any positive case in 2009 and only 5 in 2010. The phylogenetic analyses strongly indicate that the Perkinsus species infecting oysters C. rhizophorae of this study belongs to Perkinsus beihaiensis. The histology confirmed 11 cases of Perkinsus sp. infecting the C. rhizophorae in 2009, and only two cases in 2010. Nematopsis sp. was the protozoan observed with greater prevalence (up 96.7%). Other found protozoa were: Trichodina, Sphenophrya, Ancistrocoma - like and an unknown ovarian parasite. The metazoa found were the polychaete Polydora with high prevalences, a turbellarian, possibly of the genus Urastoma, an unidentified digenean metacercariae and larvae of cestode Tylocephalum. A continuous monitoring of diseases in bivalves from this natural population is recommended, since the phylogenetic analyses indicate the occurrence of P. beihaiensis

  15. Nutrient input from the Loxahatchee River Environmental Control District sewage-treatment plant to the Loxahatchee River Estuary, southeastern Florida

    USGS Publications Warehouse

    Sonntag, W.H.; McPherson, B.F.

    1984-01-01

    Two test discharges of treated-sewage effluent were made to the Loxahatchee River in February and September 1981 from the ENCON sewage-treatment plant to document nutrient loading and downstream transport of the effluent to the estuary under maximum daily discharge allowable by law (4 million gallons per day). Concentrations of total nitrogen in the effluent exceeded background concentrations by as much as 7 times during the February test, while concentrations of total phosphorus exceeded background concentrations by as much as 112 times during the September test. The effluent was transported downstream to the estuary in less than 24 hours. Discharge of treated sewage effluent to the river-estuary system in the 1981 water year accounted for less than 0.5 percent of the total nitrogen and 8 percent of the total phosphorus discharged from the major tributaries to the estuary. If maximum discharges of effluent (4 million gallons per day) were sustained throughout the year, annual nitrogen loading from the effluent would account for 5 to 18 percent of the total nitrogen input by the major tributaries to the estuary. With maximum discharges of effluent, annual phosphorus loading would exceed the amount of phosphorus input by the major tributaries to the estuary by 54 to 167 percent. (USGS)

  16. Multidrug-resistant Vibrio associated with an estuary affected by shrimp farming in Northeastern Brazil.

    PubMed

    Rocha, Rafael Dos Santos; Sousa, Oscarina Viana de; Vieira, Regine Helena Silva Dos Fernandes

    2016-04-15

    Bacteria of genus Vibrio with multidrug resistance in shrimp farm environment were recurrent. Thus, the aim of this study was to evaluate the antimicrobial resistance profile of 70 strains of Vibrio isolated from water and sediment of Acaraú estuary, Ceará, Brazil. In order to achieve this goal, disk diffusion technique was used with the following antimicrobial agents: ampicillin (Amp), aztreonam (Atm), cephalothin (Cef), cefotaxime (Ctx), ceftriaxone (Cro), ciprofloxacin (Cip), chloramphenicol (Clo), florfenicol (Flo), nitrofurantoin (Nit), gentamicin (Gen), oxytetracycline (Otc), tetracycline (Tet), streptomycin (Str), nalidixic acid (Nal), and sulfazotrim (Sut). All Vibrio strains were resistant to at least one antimicrobial agent, being verified as 17 multidrug-resistant profiles. All strains resistant to Otc and Tet were characterized to exhibit plasmidial resistance. Therefore, Vibrio strains from Acaraú estuary pose a risk to public health and aquatic culture. PMID:26876560

  17. Heavy metal anomalies in the Tinto and Odiel River and estuary system, Spain

    USGS Publications Warehouse

    Nelson, C.H.; Lamothe, P.J.

    1993-01-01

    The Tinto and Odiel rivers drain 100 km from the Rio Tinto sulphide mining district, and join at a 20-km long estuary entering the Atlantic Ocean. A reconnaissance study of heavy metal anomalies in channel sand and overbank mud of the river and estuary by semi-quantitative emission dc-arc spectrographic analysis shows the following upstream to downstream ranges in ppm (??g g-1): As 3,000 to <200, Cd 30 to <0.1, Cu 1,500 to 10, Pb 2,000 to <10, Sb 3000 to <150, and Zn 3,000 to <200. Organic-rich (1.3-2.6% total organic carbon, TOC), sandysilty overbank clay has been analyzed to represent suspended load materials. The high content of heavy metals in the overbank clay throughout the river and estuary systems indicates the importance of suspended sediment transport for dispersing heavy metals from natural erosion and anthropogenic mining activities of the sulfide deposit. The organic-poor (0.21-0.37% TOC) river bed sand has been analyzed to represent bedload transport of naturally-occurring sulfide minerals. The sand has high concentrations of metals upstream but these decrease an order of magnitude in the lower estuary. Although heavy metal contamination of estuary mouth beach sand has been diluted to background levels estuary mud exhibits increased contamination apparently related to finer grain size, higher organic carbon content, precipitation of river-borne dissolved solids, and input of anthropogenic heavy metals from industrial sources. The contaminated estuary mud disperses to the inner shelf mud belt and offshore suspended sediment, which exhibit metal anomalies from natural erosion and mining of upstream Rio Tinto sulphide lode sources (Pb, Cu, Zn) and industrial activities within the estuary (Fe, Cr, Ti). Because heavy metal contamination of Tinto-Odiel river sediment reaches or exceeds the highest levels encountered in other river sediments of Spain and Europe, a detailed analysis of metals in water and suspended sediment throughout the system, and

  18. Salt Plug Formation Caused by Decreased River Discharge in a Multi-channel Estuary

    PubMed Central

    Shaha, Dinesh Chandra; Cho, Yang-Ki

    2016-01-01

    Freshwater input to estuaries may be greatly altered by the river barrages required to meet human needs for drinking water and irrigation and prevent salt water intrusion. Prior studies have examined the salt plugs associated with evaporation and salt outwelling from tidal salt flats in single-channel estuaries. In this work, we discovered a new type of salt plug formation in the multi-channel Pasur River Estuary (PRE) caused by decreasing river discharges resulting from an upstream barrage. The formation of a salt plug in response to changes in river discharge was investigated using a conductivity-temperature-depth (CTD) recorder during spring and neap tides in the dry and wet seasons in 2014. An exportation of saline water from the Shibsa River Estuary (SRE) to the PRE through the Chunkhuri Channel occurred during the dry season, and a salt plug was created and persisted from December to June near Chalna in the PRE. A discharge-induced, relatively high water level in the PRE during the wet season exerted hydrostatic pressure towards the SRE from the PRE and thereby prevented the intrusion of salt water from the SRE to the PRE. PMID:27255892

  19. Salt Plug Formation Caused by Decreased River Discharge in a Multi-channel Estuary.

    PubMed

    Shaha, Dinesh Chandra; Cho, Yang-Ki

    2016-01-01

    Freshwater input to estuaries may be greatly altered by the river barrages required to meet human needs for drinking water and irrigation and prevent salt water intrusion. Prior studies have examined the salt plugs associated with evaporation and salt outwelling from tidal salt flats in single-channel estuaries. In this work, we discovered a new type of salt plug formation in the multi-channel Pasur River Estuary (PRE) caused by decreasing river discharges resulting from an upstream barrage. The formation of a salt plug in response to changes in river discharge was investigated using a conductivity-temperature-depth (CTD) recorder during spring and neap tides in the dry and wet seasons in 2014. An exportation of saline water from the Shibsa River Estuary (SRE) to the PRE through the Chunkhuri Channel occurred during the dry season, and a salt plug was created and persisted from December to June near Chalna in the PRE. A discharge-induced, relatively high water level in the PRE during the wet season exerted hydrostatic pressure towards the SRE from the PRE and thereby prevented the intrusion of salt water from the SRE to the PRE. PMID:27255892

  20. Occurrence and fate of triclosan and triclocarban in a subtropical river and its estuary.

    PubMed

    Lv, Min; Sun, Qian; Xu, Haili; Lin, Lifeng; Chen, Meng; Yu, Chang-Ping

    2014-11-15

    The occurrence of triclosan (TCS) and triclocarban (TCC) in a subtropical river (Jiulong River) and its estuary was investigated for two years. TCS and TCC were ubiquitously detected in the Jiulong River and its estuary. The levels of TCS and TCC ranged from less than the method detection limit to 64 ng/L and from 0.05 to 14.1 ng/L in the river, respectively. The levels of TCS and TCC in the estuary ranged from 2.56 to 27.25 ng/L and 0.38 to 5.76 ng/L, respectively. Temporal and spatial variations of TCS and TCC in the Jiulong River and its estuary were observed during the investigation. The weather conditions did not show significant correlations with TCS and TCC, whereas several water quality parameters showed high correlations with TCS and TCC. The microcosm studies showed that both direct photolysis and biodegradation contributed to TCS removal, whereas indirect photolysis was important for TCC removal in the surface water. PMID:25227953

  1. Salt Plug Formation Caused by Decreased River Discharge in a Multi-channel Estuary

    NASA Astrophysics Data System (ADS)

    Shaha, Dinesh Chandra; Cho, Yang-Ki

    2016-06-01

    Freshwater input to estuaries may be greatly altered by the river barrages required to meet human needs for drinking water and irrigation and prevent salt water intrusion. Prior studies have examined the salt plugs associated with evaporation and salt outwelling from tidal salt flats in single-channel estuaries. In this work, we discovered a new type of salt plug formation in the multi-channel Pasur River Estuary (PRE) caused by decreasing river discharges resulting from an upstream barrage. The formation of a salt plug in response to changes in river discharge was investigated using a conductivity-temperature-depth (CTD) recorder during spring and neap tides in the dry and wet seasons in 2014. An exportation of saline water from the Shibsa River Estuary (SRE) to the PRE through the Chunkhuri Channel occurred during the dry season, and a salt plug was created and persisted from December to June near Chalna in the PRE. A discharge-induced, relatively high water level in the PRE during the wet season exerted hydrostatic pressure towards the SRE from the PRE and thereby prevented the intrusion of salt water from the SRE to the PRE.

  2. River discharge controls phytoplankton dynamics in the northern San Francisco Bay estuary

    USGS Publications Warehouse

    Cloern, J.E.; Alpine, A.E.; Cole, B.E.; Wong, R.L.J.; Arthur, J.F.; Ball, M.D.

    1983-01-01

    Phytoplankton dynamics in the upper reach of the northern San Francisco Bay estuary are usually characterized by low biomass dominated by microflagellates or freshwater diatoms in winter, and high biomass dominated by neritic diatoms in summer. During two successive years of very low river discharge (the drought of 1976-77), the summer diatom bloom was absent. This is consistent with the hypothesis that formation of the diatom population maximum is a consequence of the same physical mechanisms that create local maxima of suspended sediments in partially-mixed estuaries: density-selective retention of particles within an estuarine circulation cell. Because the estuary is turbid, calculated phytoplankton growth rates are small in the central deep channel but are relatively large in lateral shallow embayments where light limination is less severe. When river discharge falls within a critical range (100-350 m3 s-1) that positions the suspended particulate maximum adjacent to the productive shallow bays, the population of neritic diatoms increases. However, during periods of high discharge (winter) or during periods of very low discharge (drought), the suspended particulate maximum is less well-defined and is uncoupled (positioned downstream or upstream) from the shallow bays of the upper estuary, and the population of neritic diatoms declines. Hence, the biomass and community composition of phytoplankton in this estuary are controlled by river discharge. ?? 1983.

  3. Variation of baroclinicity over the spring-neap cycle in the Sumjin River estuary, Korea

    NASA Astrophysics Data System (ADS)

    Cho, Eun-Byeol; Cho, Yang-Ki; Seo, Gwang-Ho; Tak, Yong-Jin; Kim, Bong-Kuk

    2015-04-01

    Vertical velocity profiles and hydrography were intensively observed using Acoustic Doppler Current Profilers and CTD to understand the variation of baroclinicity over the spring-neap tidal cycle in the Sumjin River estuary, Korea. The Sumjin River estuary is a natural estuary in Korea. The river is 212km long, a drainage area is nearly 4,896km2 and the yearly mean discharge is 86.3m3/s. The Sumjin River estuary experiences a transition from partially- or well-mixed during spring tides (St < 0.15), but stratified conditions during neap tides (St > 0.32) based on the stratification parameter (St) which is the salinity difference between surface and bottom (δS) divided by the depth averaged salinity . The CTD observation cruises were taken at flood and ebb during neap tide and spring tide. The horizontal density gradient changes over fortnightly tidal cycle. The horizontal density gradient is small during neap tide. However it during spring tide dramatically increases about six to ten times larger than neap tide. The mean flow in the Sumjin River estuary displayed typical estuarine circulation which the surface layer flows seaward and the bottom layer flows landward. However, the snapshots of the velocity profiles showed dramatic changes with the tide. Velocity shear is strong during spring tides when the tidal range was at a maximum, while velocity shear is weak during neap tides when the tidal range was at a minimum. The change of tidal range induces baroclinic variations. An analytical model was applied to evaluate the effect of horizontal density on the velocity profile variation. The velocity profiles are determined by river discharge, horizontal density variations, and tide. Density variations act as a baroclinic pressure gradient, whereas the river discharge and tides act as a horizontal barotropic pressure gradient. The velocity profiles calculated by the analytical model suggest that the variation of baroclinicity over the spring-neap cycle is mainly caused

  4. Modelling Suspended Sediment Transport in Monsoon Season: A Case Study of Pahang River Estuary, Pahang, Malaysia

    NASA Astrophysics Data System (ADS)

    Zakariya, Razak; Ahmad, Zuhairi; Saad, Shahbudin; Yaakop, Rosnan

    2013-04-01

    Sediment transport based on 2-dimensional real time model was applied to Pahang River estuary, Pahang, Malaysia and has been evaluated and verified with time series of tidal elevation, flow and suspended sediment load. Period of modelling was during highest high tide and lowest low tide in Northeast Monsoon (NE) which happened in December 2010 and Southwest Monsoon (SW) in July 2011. Simulated model outputs has been verify using Pearson's coefficient and has showed high accuracy. The validated model was used to simulate hydrodynamic and sediment transport of extreme conditions during both monsoon seasons. Based on field measurement and model simulation, tidal elevation and flow velocity, freshwater discharge of Pahang River were found to be higher during NE Monsoon. Based on the fluxes, the estuary also showed 'ebb-dominant' characteristic during highest high tide and lowest low tide in NE monsoon and normal ebbing-flooding characteristics during SW monsoon. In the Pahang River estuary, inflow and outflow patterns were perpendicular to the open boundary with circular flow formed at the shallow area in the middle of estuary during both monsoons. Referring to sea water intrusion from the river mouth, both seasons show penetration of more than 9 km (upstream input boundary) during higher high water tide. During higher lower water tide, the water intrusion stated varies which 5.6km during NE monsoon and 7.8km during SW monsoon. Regarding to the times lap during high tide, the sea water takes 2.8 hours to reach 9km upstream during NE monsoon compared to 1.9 hour during SW monsoon. The averages of suspended sediment concentration and suspended sediment load were higher during Northeast monsoon which increased the sedimentation potentials.Total of suspended sediment load discharged to the South China Sea yearly from Pahang River is approximately 96727.5 tonnes/day or 3.33 tonnes/km2/day which 442.6 tonnes/day during Northeast Monsoon and 25.3 tonnes/day during Southwest

  5. The carbohydrates in relation to mineralogic and granulometric composition of surface sediments in the karst estuary (River Krka estuary, Yugoslavia)

    NASA Astrophysics Data System (ADS)

    Hadz̆ija, Olga; Jurac̆ić, Mladen; Luić, Marija; Tonković, Maja; Jeric̆ević, Biserka

    1985-11-01

    The investigation of mineral, granulometric and chemical composition of sediments of the River Krka estuary (Yugoslavia) were performed in order to elucidate the origin of the sediments and the pattern of sedimentation. Estuarine surface sediments were found to be fine-grained with a bimodal distribution. Environmental conditions in estuarine sediments favour conservation of the organic matter (anoxic conditions). The carbohydrates in the sediments were investigated to determine whether they are of terrigenous or authigenous origin. Glucose, galactose, mannose, xylose, rhamnose, glucosamine and glucuronic acid were detected in the sediments. Their mutual relationship indicates a preferentially terrigenous source of sedimented organic material in estuarine sediments.

  6. Pollutant fate and spatio-temporal variability in the choptank river estuary: factors influencing water quality.

    PubMed

    Whitall, David; Hively, W Dean; Leight, Andrew K; Hapeman, Cathleen J; McConnell, Laura L; Fisher, Thomas; Rice, Clifford P; Codling, Eton; McCarty, Gregory W; Sadeghi, Ali M; Gustafson, Anne; Bialek, Krystyna

    2010-04-01

    Restoration of the Chesapeake Bay, the largest estuary in the United States, is a national priority. Documentation of progress of this restoration effort is needed. A study was conducted to examine water quality in the Choptank River estuary, a tributary of the Chesapeake Bay that since 1998 has been classified as impaired waters under the Federal Clean Water Act. Multiple water quality parameters (salinity, temperature, dissolved oxygen, chlorophyll a) and analyte concentrations (nutrients, herbicide and herbicide degradation products, arsenic, and copper) were measured at seven sampling stations in the Choptank River estuary. Samples were collected under base flow conditions in the basin on thirteen dates between March 2005 and April 2008. As commonly observed, results indicate that agriculture is a primary source of nitrate in the estuary and that both agriculture and wastewater treatment plants are important sources of phosphorus. Concentrations of copper in the lower estuary consistently exceeded both chronic and acute water quality criteria, possibly due to use of copper in antifouling boat paint. Concentrations of copper in the upstream watersheds were low, indicating that agriculture is not a significant source of copper loading to the estuary. Concentrations of herbicides (atrazine, simazine, and metolachlor) peaked during early-summer, indicating a rapid surface-transport delivery pathway from agricultural areas, while their degradation products (CIAT, CEAT, MESA, and MOA) appeared to be delivered via groundwater transport. Some in-river processing of CEAT occurred, whereas MESA was conservative. Observed concentrations of herbicide residues did not approach established levels of concern for aquatic organisms. Results of this study highlight the importance of continued implementation of best management practices to improve water quality in the estuary. This work provides a baseline against which to compare future changes in water quality and may be used

  7. Pollutant fate and spatio-temporal variability in the choptank river estuary: Factors influencing water quality

    USGS Publications Warehouse

    Whitall, D.; Hively, W.D.; Leight, A.K.; Hapeman, C.J.; McConnell, L.L.; Fisher, T.; Rice, C.P.; Codling, E.; McCarty, G.W.; Sadeghi, A.M.; Gustafson, A.; Bialek, K.

    2010-01-01

    Restoration of the Chesapeake Bay, the largest estuary in the United States, is a national priority. Documentation of progress of this restoration effort is needed. A study was conducted to examine water quality in the Choptank River estuary, a tributary of the Chesapeake Bay that since 1998 has been classified as impaired waters under the Federal Clean Water Act. Multiple water quality parameters (salinity, temperature, dissolved oxygen, chlorophyll a) and analyte concentrations (nutrients, herbicide and herbicide degradation products, arsenic, and copper) were measured at seven sampling stations in the Choptank River estuary. Samples were collected under base flow conditions in the basin on thirteen dates between March 2005 and April 2008. As commonly observed, results indicate that agriculture is a primary source of nitrate in the estuary and that both agriculture and wastewater treatment plants are important sources of phosphorus. Concentrations of copper in the lower estuary consistently exceeded both chronic and acute water quality criteria, possibly due to use of copper in antifouling boat paint. Concentrations of copper in the upstream watersheds were low, indicating that agriculture is not a significant source of copper loading to the estuary. Concentrations of herbicides (atrazine, simazine, and metolachlor) peaked during early-summer, indicating a rapid surface-transport delivery pathway from agricultural areas, while their degradation products (CIAT, CEAT, MESA, and MOA) appeared to be delivered via groundwater transport. Some in-river processing of CEAT occurred, whereas MESA was conservative. Observed concentrations of herbicide residues did not approach established levels of concern for aquatic organisms. Results of this study highlight the importance of continued implementation of best management practices to improve water quality in the estuary. This work provides a baseline against which to compare future changes in water quality and may be used

  8. Cross sections of the Hudson River estuary from Troy to New York City, New York

    USGS Publications Warehouse

    Stedfast, D.A.

    1980-01-01

    Data on channel geometry of the Hudson River estuary at 125 cross sections between the Federal Dam at Troy and the norhtern limits of New York City (133 miles) are presented for use in hydraulic modeling, tidal studies, traveltime and water-quality studies, and other uses requiring knowledge of Hudson River channel properties. The data were obtained from field surveys of the estuary conducted by boat with a fathometer in 1966-69. Water-surface elevations were not recorded during the fathometer runs but were calculated in 1979 from information on tide variations in the estuary and from stage data collected at Albany and New York City. Topographic maps and field reconaissance were used to extend the ends of the cross sections beyond 100-year flood stage. Channel-configuration data are presented as perspective plots and in a table; also included are strip maps showing the location of the cross sections. (USGS)

  9. Leachable particulate iron in the Columbia River, estuary, and near-field plume

    NASA Astrophysics Data System (ADS)

    Lippiatt, Sherry M.; Brown, Matthew T.; Lohan, Maeve C.; Berger, Carolyn J. M.; Bruland, Kenneth W.

    2010-03-01

    This study examines the distribution of leachable particulate iron (Fe) in the Columbia River, estuary, and near-field plume. Surface samples were collected during late spring and summer of 2004-2006 as part of four River Influence on Shelf Ecosystems (RISE) cruises. Tidal amplitude and river flow are the primary factors influencing the estuary leachable particulate Fe concentrations, with greater values during high flow and/or spring tides. Near the mouth of the estuary, leachable particulate Fe [defined as the particulate Fe solubilized with a 25% acetic acid (pH 2) leach containing a weak reducing agent to reduce Fe oxyhydroxides and a short heating step to access intracellular Fe] averaged 770 nM during either spring tide or high flow, compared to 320 nM during neap tide, low flow conditions. In the near-field Columbia River plume, elevated leachable particulate Fe concentrations occur during spring tides and/or higher river flow, with resuspended shelf sediment as an additional source to the plume during periods of coastal upwelling and spring tides. Near-field plume concentrations of leachable particulate Fe (at a salinity of 20) averaged 660 nM during either spring tide or high flow, compared to 300 nM during neap tide, low flow conditions. Regardless of tidal amplitude and river flow, leachable particulate Fe concentrations in both the river/estuary and near-field plume are consistently one to two orders of magnitude greater than dissolved Fe concentrations. The Columbia River is an important source of reactive Fe to the productive coastal waters off Oregon and Washington, and leachable particulate Fe is available for solubilization following biological drawdown of the dissolved phase. Elevated leachable Fe concentrations allow coastal waters influenced by the Columbia River plume to remain Fe-replete and support phytoplankton production during the spring and summer seasons.

  10. Factors Contributing to Hypoxia in the Minjiang River Estuary, Southeast China.

    PubMed

    Zhang, Peng; Pang, Yong; Pan, Hongche; Shi, Chengchun; Huang, Yawen; Wang, Jianjian

    2015-08-01

    Dissolved oxygen (DO) is not only a fundamental parameter of coastal water quality, but also an indication of organics decomposed in water and their degree of eutrophication. There has been a concern about the deterioration of dissolved oxygen conditions in the Minjiang River Estuary, the longest river in Fujian Province, Southeast China. In this study, the syntheses effects on DO was analyzed by using a four year time series of DO concentration and ancillary parameters (river discharge, water level, and temperature) from the Fuzhou Research Academy of Environmental Sciences, at three automated stations along the Minjiang River Estuary. Hypoxia occurred exclusively in the fluvial sections of the estuary during the high temperature and low river discharge period and was remarkably more serious in the river reach near the large urban area of Fuzhou. Enhancement of respiration by temperature and discharge of domestic sewage and industrial wastewater, versus regeneration of waters and dilution of pollutant concentration with increased river discharge, which regarded as the dominant antagonist processes that controlled the appearance of seasonal hypoxia. During the high temperature and the drought period, minimal mainstream flow above 700 m(3)Ÿs(-1), reduction of pollutants and forbidding sediment dredging in the South Channel should be guaranteed for strong supports on water quality management and drinking water source protection. PMID:26270670

  11. Factors Contributing to Hypoxia in the Minjiang River Estuary, Southeast China

    PubMed Central

    Zhang, Peng; Pang, Yong; Pan, Hongche; Shi, Chengchun; Huang, Yawen; Wang, Jianjian

    2015-01-01

    Dissolved oxygen (DO) is not only a fundamental parameter of coastal water quality, but also an indication of organics decomposed in water and their degree of eutrophication. There has been a concern about the deterioration of dissolved oxygen conditions in the Minjiang River Estuary, the longest river in Fujian Province, Southeast China. In this study, the syntheses effects on DO was analyzed by using a four year time series of DO concentration and ancillary parameters (river discharge, water level, and temperature) from the Fuzhou Research Academy of Environmental Sciences, at three automated stations along the Minjiang River Estuary. Hypoxia occurred exclusively in the fluvial sections of the estuary during the high temperature and low river discharge period and was remarkably more serious in the river reach near the large urban area of Fuzhou. Enhancement of respiration by temperature and discharge of domestic sewage and industrial wastewater, versus regeneration of waters and dilution of pollutant concentration with increased river discharge, which regarded as the dominant antagonist processes that controlled the appearance of seasonal hypoxia. During the high temperature and the drought period, minimal mainstream flow above 700 m3·s−1, reduction of pollutants and forbidding sediment dredging in the South Channel should be guaranteed for strong supports on water quality management and drinking water source protection. PMID:26270670

  12. Evaluating Cumulative Ecosystem Response to Restoration Projects in the Columbia River Estuary, Annual Report 2005

    SciTech Connect

    Diefenderfer, Heida L.; Thom, Ronald M.; Borde, Amy B.; Roegner, G. C.; Whiting, Allan H.; Johnson, Gary E.; Dawley, Earl; Skalski, John R.; Vavrinec, John; Ebberts, Blaine D.

    2006-12-20

    This report is the second annual report of a six-year project to evaluate the cumulative effects of habitat restoration projects in the Columbia River Estuary, conducted by Pacific Northwest National Laboratory's Marine Sciences Laboratory, NOAA's National Marine Fisheries Service Pt. Adams Biological Field Station, and the Columbia River Estuary Study Taskforce for the US Army Corps of Engineers. In 2005, baseline data were collected on two restoration sites and two associated reference sites in the Columbia River estuary. The sites represent two habitat types of the estuary--brackish marsh and freshwater swamp--that have sustained substantial losses in area and that may play important roles for salmonids. Baseline data collected included vegetation and elevation surveys, above and below-ground biomass, water depth and temperature, nutrient flux, fish species composition, and channel geometry. Following baseline data collection, three kinds of restoration actions for hydrological reconnection were implemented in several locations on the sites: tidegate replacements (2) at Vera Slough, near the city of Astoria in Oregon State, and culvert replacements (2) and dike breaches (3) at Kandoll Farm in the Grays River watershed in Washington State. Limited post-restoration data were collected: photo points, nutrient flux, water depth and temperature, and channel cross-sections. In subsequent work, this and additional post-restoration data will be used in conjunction with data from other sites to estimate net effects of hydrological reconnection restoration projects throughout the estuary. This project is establishing methods for evaluating the effectiveness of individual projects and a framework for assessing estuary-wide cumulative effects including a protocol manual for monitoring restoration and reference sites.

  13. Habitat use and trophic position effects on contaminant bioaccumulation in St. Louis River Estuary fishes

    EPA Science Inventory

    The objective of our study was to determine the relationship between fish tissue stable isotope composition and total mercury or polychlorinated biphenyl (PCB) concentrations in the St. Louis River estuary food web. We sampled two resident fishes, Yellow Perch (Perca flavescens) ...

  14. The faucet snail (Bithynia tentaculata) invades the St. Louis River Estuary

    EPA Science Inventory

    The European-origin faucet snail (Bithynia tentaculata) now numbers among the aquatic invasive species present in the St. Louis River Estuary. This snail has been in the lower Great Lakes since the early 20th century but is new to the Lake Superior basin. We found faucet snails...

  15. MEASURED CONCENTRATIONS OF HERBICIDES AND MODEL PREDICTIONS OF ATRAZINE FATE IN THE PATUXENT RIVER ESTUARY

    EPA Science Inventory

    McConnell, Laura L., Jennifer A. Harman-Fetcho and James D. Hagy, III. 2004. Measured Concentrations of Herbicides and Model Predictions of Atrazine Fate in the Patuxent River Estuary. J. Environ. Qual. 33(2):594-604. (ERL,GB X1051).

    The environmental fate of herbicides i...

  16. Time Series Analysis of Water Level and Temperature in the St Louis River Estuary

    EPA Science Inventory

    Pressure and temperature loggers were deployed at 9 sites in the St Louis River estuary between 6/23 10/31 2011. A reference sensor was place on the shore to correct pressure data. Sensors were paced at <1 m depth in Allouez Bay, Superior Bay, near Hearding Island, WLSSD Bay, th...

  17. PARASITIC AND SYMBIONIC FAUNA IN OYSTERS (CRASSOSTREA VIRGINICA) COLLECTED FROM THE CALOOSAHATCHEE RIVER AND ESTUARY, FLORIDA

    EPA Science Inventory



    Studies of oysters, Crassostrea virginica, collected from ten sites in the Caloosahatchee River and Estuary, Florida, revealed a varied parasite and symbiotic fauna that have never been reported from this area. Organisms observed included ovacystis virus infecting gametes...

  18. The Partitioning of Triclosan between Aqueous and Particulate Phases in the Hudson River Estuary

    EPA Science Inventory

    The distribution of Triclosan within the Hudson River Estuary can be explained by a balance among the overall effluent inputs from municipal sewage treatment facilities, dilution of Triclosan concentrations in the water column with freshwater and seawater inputs, removal of Tricl...

  19. A predictive model for floating leaf vegetation in the St. Louis River Estuary

    EPA Science Inventory

    In July 2014, USEPA staff was asked by MPCA to develop a predictive model for floating leaf vegetation (FLV) in the St. Louis River Estuary (SLRE). The existing model (Host et al. 2012) greatly overpredicts FLV in St. Louis Bay probably because it was based on a limited number of...

  20. Distribution of submerged aquatic vegetation in the St. Louis River estuary: Maps and models

    EPA Science Inventory

    In late summer of 2011 and 2012 we used echo-sounding gear to map the distribution of submerged aquatic vegetation (SAV) in the St. Louis River Estuary (SLRE). From these data we produced maps of SAV distribution and we created logistic models to predict the probability of occurr...

  1. [Shrimp community structure and its influential factors in the Jiaojiang River estuary during spring and autumn].

    PubMed

    Qi, Hai-Ming; Sun, Yue; Xu, Zhao-Li; Sun, Lu-Feng; Gao, Qian; Que, Jiang-Long; Tian, Wei

    2013-12-01

    Based on the data from two oceanographic surveys during April and October 2010, the spatial and seasonal variations in composition, dominance, and diversity of shrimp communities, as well as the influential factors in the Jiaojiang River estuary were analyzed. A total of 16 species of shrimp were found, which belonged to 12 families under 8 genera. 14 species of shrimp were found in spring (April) and 12 species in autumn (October). With the employment of index of relative importance (IRI), in spring 6 dominant species were identified, as Acetes chinensis, Alpheus distinguendus, Parapenaeopsis hardwickii, Leptochela gracilis, Alpheus juponicus and Palaemon gravieri, and in autumn 3 dominant species were found as Solenocera crassicornis, Parapenaeopsis hardwickii and Metapenaeus joyneri. Eurythermal and eurysaline shrimp community prevailed in the Jiaojiang River estuary, followed by eurythermal and hyposaline shrimp community. Margalef index (D), Shannon index (H) and Pielou's evenness index were used to evaluate the diversity of shrimp community in the studied area. The stations with higher value of D and H were mainly located in the west of the Dachen Island, whereas the Pielou's evenness index was stable all across the Jiaojiang River estuary. By hierarchical cluster analysis and non-metric multidimensional scaling (NMDS) method, the results indicated that shrimp communities had significant seasonal and spatial variations. Depth was the most important factor that affected variations in the shrimp community structure in the Jiaojiang River estuary. PMID:24697077

  2. MODELLING KEPONE IN THE STRIPED BASS FOOD CHAIN OF THE JAMES RIVER ESTUARY

    EPA Science Inventory

    A mathematical model that computes the accumulation of Kepone in the striped bass food chain of the James River estuary was developed. The purpose of the model was to help understand the relationship of Kepone levels in important fish species to sediment and water column Kepone c...

  3. Protocols for Monitoring Habitat Restoration Projects in the Lower Columbia River and Estuary

    SciTech Connect

    Roegner, G. Curtis; Diefenderfer, Heida L.; Borde, Amy B.; Thom, Ronald M.; Dawley, Earl M.; Whiting, Allan H.; Zimmerman, Shon A.; Johnson, Gary E.

    2008-04-25

    Protocols for monitoring salmon habitat restoration projects are essential for the U.S. Army Corps of Engineers' environmental efforts in the Columbia River estuary. This manual provides state-of-the science data collection and analysis methods for landscape features, water quality, and fish species composition, among others.

  4. Nutrient Budgets and Management Actions in the Patuxent River Estuary, Maryland

    EPA Science Inventory

    Multi-year nitrogen (N) and phosphorus (P) budgets were developed for the Patuxent River estuary, a seasonally stratified and moderately eutrophic tributary of Chesapeake Bay. Major inputs (point, diffuse, septic and direct atmospheric) were measured for 13 years during which la...

  5. Evaluation of a long-term hindcast simulation for the Columbia River estuary

    NASA Astrophysics Data System (ADS)

    Kärnä, Tuomas; Baptista, António M.

    2016-03-01

    In order to simulate the biogeochemical function of estuaries across the land-ocean continuum, circulation models must represent a cascade of complex physical processes spanning several spatial and temporal scales. Furthermore, governing physical processes tend to vary under different flow regimes, in response to external forcings. Model validation must therefore cover all relevant flow regimes and span sufficiently long time to represent transient and slowly-varying phenomena. We focus in a multi-year hindcast simulation of the Columbia River estuary - a mesotidal, river-dominated estuary that is also influenced by coastal upwelling in an Eastern Boundary Current system. Model skill is assessed against long-term observational time series, covering the lower estuary (for salinity) as well as most of the tidal river (for water temperature and elevation). In addition, high-resolution profiles of velocity and salinity are used to study salt transport mechanisms at a single station. Results indicate that the model captures the estuarine dynamics of the system, but the skill depends on the flow regime: In general the model performs far better during spring tides (i.e., under partially mixed or time-dependent salt wedge regimes) than under neap tides (i.e., salt wedge and strongly stratified regimes). While the model accurately represents tidal salt transport mechanisms, it tends to underestimate gravitational transport which becomes more important under neap tide conditions. Furthermore, the skill decreases during high river discharge periods, because the model has difficulty capturing the extremely strong stratification characteristic to those periods.

  6. Optical water quality of a blackwater river estuary: the Lower St. Johns River, Florida, USA

    NASA Astrophysics Data System (ADS)

    Gallegos, Charles L.

    2005-04-01

    This paper reports measurements of absorption and scattering coefficients in relation to standard water quality measurements in the St. Johns River (Florida, USA), a blackwater river in which phytoplankton chlorophyll and non-algal particulates as well as colored dissolved organic matter (CDOM) contribute substantially to the inherent optical properties of the water. Extremely high concentrations of CDOM in this river present special problems for the measurement of inherent optical properties, such as the presence of very fine particulate matter that passes through most glass fiber filters. Empirical relationships are presented for estimating true dissolved absorption at very high CDOM concentrations. Specific-absorption and -scattering coefficients of suspended particulate matter varied widely, but appeared to decline steadily with salinity at salinities above 5, consistent with increasing influence of large-sized, unconsolidated mineral particulates with increasing tidal energy near the estuary mouth. Relationships are given for prediction of inherent optical properties from water quality concentrations for use in radiative transfer modeling, and changes in water quality measurements are recommended that can avoid the need for empirical corrections.

  7. Chiral source apportionment of polychlorinated biphenyls to the Hudson River estuary atmosphere and food web.

    PubMed

    Asher, Brian J; Wong, Charles S; Rodenburg, Lisa A

    2007-09-01

    The New York/New Jersey Harbor Estuary is subject to significant contamination of polychlorinated biphenyls (PCBs) from numerous sources, including the historically contaminated Upper Hudson River, stormwater runoff and sewer overflows, and atmospheric deposition from PCBs originating from the surrounding urban area. However, the relative importance of these sources to the estuary's food web is not fully understood. Sources of PCBs to the estuary were apportioned using chiral signatures of PCBs in air, water, total suspended matter, phytoplankton, and sediment. PCBs 91, 95, 136, and 149 were racemic in the atmosphere of the estuary. However, the other phases contained nonracemic PCB 95 and to a lesser extent PCB 149. Thus, the predominant atmospheric source of these congeners is likely unweathered local pollution and not volatilization from the estuary. The similarity in chiral signatures in the other phases is consistent with dynamic contaminant exchange among them. Chiral signatures in the dissolved phase and total suspended matter were correlated with Upper Hudson discharge, suggesting thatthe delivery of nonracemic contaminated sediment from the Upper Hudson, not the atmosphere, controls phytoplankton uptake of some PCBs. Thus, measures to control PCB contamination in the Upper Hudson should be effective in reducing loadings to the estuary's aquatic ecosystem. PMID:17937297

  8. Use of glacier river-fed estuary channels by juvenile coho salmon: transitional or rearing habitats?

    USGS Publications Warehouse

    Hoem Neher, Tammy D.; Rosenberger, Amanda E.; Zimmerman, Christian E.; Walker, Coowe M.; Baird, Steven J.

    2014-01-01

    Estuaries are among the most productive ecosystems in the world and provide important rearing environments for a variety of fish species. Though generally considered important transitional habitats for smolting salmon, little is known about the role that estuaries serve for rearing and the environmental conditions important for salmon. We illustrate how juvenile coho salmonOncorhynchus kisutch use a glacial river-fed estuary based on examination of spatial and seasonal variability in patterns of abundance, fish size, age structure, condition, and local habitat use. Fish abundance was greater in deeper channels with cooler and less variable temperatures, and these habitats were consistently occupied throughout the season. Variability in channel depth and water temperature was negatively associated with fish abundance. Fish size was negatively related to site distance from the upper extent of the tidal influence, while fish condition did not relate to channel location within the estuary ecotone. Our work demonstrates the potential this glacially-fed estuary serves as both transitional and rearing habitat for juvenile coho salmon during smolt emigration to the ocean, and patterns of fish distribution within the estuary correspond to environmental conditions.

  9. A numerical study of the plume in Cape Fear River Estuary and adjacent coastal ocean

    NASA Astrophysics Data System (ADS)

    Xia, M.; Xia, L.; Pietrafesa, L. J.

    2006-12-01

    Cape Fear River Estuary (CFRE), located in southeast North Carolina, is the only river estuary system in the state which is directly connected to the Atlantic Ocean. It is also an important nursery for economically and ecologically important juvenile fish, crabs, shrimp, and other species because of the tidal influence and saline waters. In this study, Environmental Fluid Dynamic Code (EFDC) is used to simulate the salinity plume and trajectory distribution at the mouth of the CFRE and adjacent coastal ocean. Prescribed with the climatological freshwater discharge rates in the rivers, the modeling system was used to simulate the salinity plume and trajectory distribution distribution in the mouth of the CFRE under the influence of climatological wind conditions and tidal effect. We analyzed the plume formation processes and the strong relationship between the various plume distributions with respect to the wind and river discharge in the region. The simulations also indicate that strong winds tend to reduce the surface CFRE plume size and distorting the bulge region near the estuary mouth due to enhanced wind induced surface mixing. Even moderate wind speeds could fully reverse the buoyancy-driven plume structure in CFRE under normal river discharge conditions. Tide and the river discharge also are important factors to influence the plume structure. The comparions between the distribution of salinity plume and trajectory also are discussed in the study.

  10. Family-level AMBI is valid for use in the north-eastern Atlantic but not for assessing the health of microtidal Australian estuaries

    NASA Astrophysics Data System (ADS)

    Tweedley, James R.; Warwick, Richard M.; Clarke, K. Robert; Potter, Ian C.

    2014-03-01

    Analysis of benthic macroinvertebrate samples at a higher taxonomic level than species, e.g. family, potentially provides a more cost-effective protocol for environmental impact assessments and monitoring as it requires less time, funds and taxonomic expertise. Using the AMBI database, species ecological group scores are shown to be coherent within families. Faunal data from a wide range of environmental impact scenarios in the north-eastern Atlantic demonstrate that AMBI, calculated from mean values for families, exhibits a strong linear relationship with species-level AMBI, the correlation improving by using square-root transformed rather than untransformed abundances. In many regions of the world, however, the sensitivity of benthic macroinvertebrates to environmental perturbations is unknown, precluding the use of AMBI for environmental assessments. Yet the families are essentially the same as in the AMBI database. The utility of family-level AMBI is tested using data for four south-western Australian estuaries previously subjected to environmental quality assessments, but where only 17 species of the 144 taxa are included in the AMBI database. Although family-level AMBI scores reflect differences in environmental quality spatially and temporally within an estuary, they do not follow variations in environmental quality among estuaries. Indeed, south-western Australia estuaries are numerically dominated by families with high AMBI scores, probably due to the detrimental effects of natural accumulations of organic material in estuaries with long residence times. As taxonomic distinctness follows trends in environmental quality among estuaries, as well as temporally and spatially within a system, it provides an appropriate substitute for assessing the 'heath' of microtidal estuaries.

  11. Sediment quality triad assessment of an industrialized estuary of the northeastern USA.

    PubMed

    Iannuzzi, Timothy J; Armstrong, Tina N; Long, Edward R; Iannuzzi, Jacqueline; Ludwig, David F

    2008-04-01

    The lower Passaic River in northern New Jersey (USA) has been heavily industrialized since the mid-nineteenth century and its shoreline and aquatic habitats degraded or destroyed. Similar to other urban systems, Passaic River sediments, both surface and buried, historically have contained elevated levels of numerous contaminants that may pose risks to ecological receptors and humans. Sediments from 15 stations in the lower Passaic River and 3 reference stations in the Mullica River in southern New Jersey were sampled in 1999 and characterized for chemical contamination, toxicity, and impairment of the benthic community. The objective of this study was to determine the incidence, degree, and nature of degraded surficial sediments in the area to support subsequent plans for restoration of the system. Results demonstrated that Passaic River sediments had concentrations of many organic and inorganic contaminants at levels significantly greater than the reference area and effect-based guidelines. Sediments were toxic to marine amphipods at 11 stations and the benthic assemblages were impaired relative to the reference area at all stations. The weight-of-evidence of this sediment quality triad (SQT) assessment indicates that impacts from multiple contaminants are occurring throughout the lower Passaic River and, that these impacts must be evaluated further and addressed as part of ongoing restoration initiatives for the river. PMID:17588158

  12. Enhanced abundance and diversity of ammonia-oxidizing Archaea in the Pearl River estuary

    NASA Astrophysics Data System (ADS)

    Xie, W.; Zhang, C. L.; Wang, P.; Zhou, X.; Guo, W.

    2014-12-01

    Thaumarchaeota are recently recognized as an important group of Archaea that can perform aerobic oxidation of ammonia in a wide range of environments. The goal of this study was to evaluate changes in abundance and diversity of planktonic ammonia-oxidizing Archaea (e.g., Thaumarchaeota) along a salinity gradient from the lower Pearl River to the northern South China Sea. Quantitative PCR and sequencing of total archaeal 16S rRNA gene and the archaeal amoA gene were performed on suspended particulate organic matter collected in different seasons from the freshwater to the ocean water. Total amoA gene copies and relative abundance of Thaumarchaeota all peaked in the estuary where salinity ranged between 4.5‰ and 26.7‰. The diversity of archaeal amoA gene was also highest in the estuary. Seasonality and SiO32- appear to be two major factors affecting the distribution of subclusters of archaeal amoA genes. For example, Nitrosopumilus subcluster 7.1 was most abundant in winter in fresh water, whereas Nitrososphaera were more abundant in summer. Samples collected from the area around Wanshan Island, which is located at the outermost part of the Pearl River estuary, had high abundance of unclassified archaeal amoA genes, suggesting some new groups of Thaumarchaeota might inhabit this water body. Overall, the high abundance and diversity of Thaumarchaeota in the Pearl River estuary may indicate enhanced role of AOA in nitrogen cycle in this dynamic ecosystem.

  13. A water-quality study of the tidal Potomac River and Estuary; an overview

    USGS Publications Warehouse

    Callender, Edward, (Edited By); Carter, Virginia; Hahl, D.C.; Hitt, Kerie; Schultz, Barbara I.

    1984-01-01

    The U.S. Geological Survey began a 5-year interdisciplinary study of the tidal Potomac River and Estuary in October of 1977. The objectives of the study are: (1) to provide a basic understanding of physical, chemical, and biological processes; (2) to develop flow and transport models to predict the movement and fate of nutrients and algaes and (3) to develop efficient techniques for the study of tidal rivers and estuaries. The ultimate goal is to aid water-quality decision-making for the tidal Potomac River and Estuary. The study is being conducted by scientists from many disciplines involved in 14 interrelated studies. These scientists are addressing five major problem areas: nutrient enrichment, algal blooms, dissolved oxygen, sedimentation, and effects of water quality on living resources. Preliminary results show that treatment of sewage has reduced the concentration load of organic carbon and phosphorus below that of the 1960's and 1970's, and changed the form of dissolved nitrogen in the tidal river. Concentrations of chlorophyll a during the study period were lower than those experienced during the massive algal blooms of the 1960's. Dissolved oxygen concentrations fluctuate in response to changes in algal populations, but remain above the Environmental Protection Agency limits during the summer low-flow period. Sedimentation rates have accelerated during the past 50-70 years due to urbanization and farming. Asian clams have recently invaded the tidal river; submersed aquatic vegetation has declined since the early 1900's, but conditions may now favor its return.

  14. Estimating sediment budgets at the interface between rivers and estuaries with application to the Sacramento-San Joaquin River Delta

    USGS Publications Warehouse

    Wright, S.A.; Schoellhamer, D.H.

    2005-01-01

    [1] Where rivers encounter estuaries, a transition zone develops where riverine and tidal processes both affect sediment transport processes. One such transition zone is the Sacramento-San Joaquin River Delta, a large, complex system where several rivers meet to form an estuary (San Francisco Bay). Herein we present the results of a detailed sediment budget for this river/estuary transitional system. The primary regional goal of the study was to measure sediment transport rates and pathways in the delta in support of ecosystem restoration efforts. In addition to achieving this regional goal, the study has produced general methods to collect, edit, and analyze (including error analysis) sediment transport data at the interface of rivers and estuaries. Estimating sediment budgets for these systems is difficult because of the mixed nature of riverine versus tidal transport processes, the different timescales of transport in fluvial and tidal environments, and the sheer complexity and size of systems such as the Sacramento-San Joaquin River Delta. Sediment budgets also require error estimates in order to assess whether differences in inflows and outflows, which could be small compared to overall fluxes, are indeed distinguishable from zero. Over the 4 year period of this study, water years 1999-2002, 6.6 ?? 0.9 Mt of sediment entered the delta and 2.2 ?? 0.7 Mt exited, resulting in 4.4 ?? 1.1 Mt (67 ?? 17%) of deposition. The estimated deposition rate corresponding to this mass of sediment compares favorably with measured inorganic sediment accumulation on vegetated wetlands in the delta.

  15. Spatial distribution of dissolved cadmium in the Jiulong river-estuary system: Relevance of anthropogenic perturbation

    NASA Astrophysics Data System (ADS)

    Wang, Deli; Yang, Xiqian; Zhai, Weidong; Li, Yan; Hong, Huasheng

    2015-12-01

    This study first examined the spatial distribution of dissolved cadmium (Cd) along with other hydrochemical parameters in a large subtropical river estuary system (the Jiulong River-Estuary, China) between 2008 and 2010, aiming to evaluate the impacts of the recently increasing anthropogenic perturbation in natural waters. The results showed that dissolved Cd was variable in the watershed with sporadically high concentrations (>0.6 nmol L-1). The significantly positive correlation of dissolved Cd with phosphate in the watershed (May 2008: dissolved Cd=0.22*P+0.0062, r=0.64, p<0.05) indicated that dissolved Cd levels have been elevated along with P by the increasing agricultural discharges and/or sewage effluents. The estuary was characterized with decreased levels of dissolved Cd in the highly turbid upper part (salinity: <5; dissolved Cd: <0.1 nmol L-1; Total Suspended Matter: 100-300 mg/L), and a mid-salinity maximum of dissolved Cd in the middle part, which were higher in Summer high river discharge period (0.40-0.54 nmol L-1) than in Fall low river discharge period (0.25-0.35 nmol L-1). Dissolved Cd generally decreased outwards in the lower estuary and nearby coastal waters as mixed with the low Cd-content seawater offshore (dissolved Cd= -0.025*Salinity+0.96, r=0.60, p<0.05). In particular, an enhancement of dissolved Cd (by ~0.2 nmol L-1) was observed in the lower estuary and estuarine plume zone as a result of sewage discharges nearby and/or Cd-enriched submarine groundwater discharges. Summarily, our exemplary study provides clear evidence that China's natural waters are currently subject to local perturbation due to the recently increasing anthropogenic activities.

  16. Phytoplankton dynamics in and near the highly eutrophic Pearl River Estuary, South China Sea

    NASA Astrophysics Data System (ADS)

    Qiu, Dajun; Huang, Liangmin; Zhang, Jianlin; Lin, Senjie

    2010-02-01

    The dynamics of size-fractionated phytoplankton along the salinity gradient in the Pearl River Estuary and the adjacent near-shore oceanic water was investigated using microscopic, flow cytometric, and chlorophyll analyses in the early spring (March) and early autumn (September) of 2005. In the inner part of the estuary where salinity was less than 30, the phytoplankton community was dominated by micro- and nano-sized (3-200 μm) cells, particularly the diatom Skeletonema costatum, both in early spring and early autumn. In areas where salinity >30, including the mixing zone and nearshore oceanic water, micro- and nano-sized cell populations dominated the phytoplankton assemblage during early spring when influence of river discharge was minimal, whereas pico-sized (≤3 μm) cell populations were dominant during early autumn as a result of strong river discharge in the summer, with Synechococcus and pico-eukaryotes being predominant. Picophytoplankton were two orders of magnitude more abundant in early autumn (10 6 cells mL -1) than in early spring in the nearshore oceanic water. Nutrients delivered by freshwater input to the estuary were pushed toward high salinity (>30) areas as a result of short residence time, exerting a strong influence on phytoplankton abundance, especially picophytoplankton in the nearshore, otherwise oligotrophic, water. Influenced by high abundance of DIN and limitation in phosphorus, picophytoplankton in the adjacent nearshore oceanic water rose to prominence seasonally. Our results indicate that eutrophication in the Pearl River Estuary not only stimulates the growth of S. costatum in the nutrient-rich areas of the estuary but also appears to promote the growth of Synechococcus and pico-eukaryotes in the adjacent usually oligotrophic oceanic water at least during our autumn cruise.

  17. Biogeochemical transport in the Loxahatchee River estuary, Florida: The role of submarine groundwater discharge

    USGS Publications Warehouse

    Swarzenski, P.W.; Orem, W.H.; McPherson, B.F.; Baskaran, M.; Wan, Y.

    2006-01-01

    The distributions of dissolved organic carbon (DOC), Ba, U, and a suite of naturally occurring radionuclides in the U/Th decay series (222Rn, 223,224,226,228Ra) were studied during high- and low-discharge conditions in the Loxahatchee River estuary, Florida to examine the role of submarine groundwater discharge in estuarine transport. The fresh water endmember of this still relatively pristine estuary may reflect not only river-borne constituents, but also those advected during active groundwater/surface water (hyporheic) exchange. During both discharge conditions, Ba concentrations indicated slight non-conservative mixing. Such Ba excesses could be attributed either to submarine groundwater discharge or particle desorption processes. Estuarine dissolved organic carbon concentrations were highest at salinities closest to zero. Uranium distributions were lowest in the fresh water sites and mixed mostly conservatively with an increase in salinity. Suspended particulate matter (SPM) concentrations were generally lowest ( 28??dpm L- 1) at the freshwater endmember of the estuary and appear to identify regions of the river most influenced by the discharge of fresh groundwater. Activities of four naturally occurring isotopes of Ra (223,224,226,228Ra) in this estuary and select adjacent shallow groundwater wells yield mean estuarine water-mass transit times of less than 1 day; these values are in close agreement to those calculated by tidal prism and tidal frequency. Submarine groundwater discharge rates to the Loxahatchee River estuary were calculated using a tidal prism approach, an excess 226Ra mass balance, and an electromagnetic seepage meter. Average SGD rates ranged from 1.0 to 3.8 ?? 105??m3 d- 1 (20-74??L m- 2 d- 1), depending on river-discharge stage. Such calculated SGD estimates, which must include both a recirculated as well as fresh water component, are in close agreement with results obtained from a first-order watershed mass balance. Average submarine

  18. Effects of Nitrogen Availability and Form on Phytoplankton Growth in a Eutrophied Estuary (Neuse River Estuary, NC, USA)

    PubMed Central

    Paerl, Hans W.; Wetz, Michael S.

    2016-01-01

    Nitrogen availability and form are important controls on estuarine phytoplankton growth. This study experimentally determined the influence of urea and nitrate additions on phytoplankton growth throughout the growing season (March 2012, June 2011, August 2011) in a temperate, eutrophied estuary (Neuse River Estuary, North Carolina, USA). Photopigments (chlorophyll a and diagnostic photopigments: peridinin, fucoxanthin, alloxanthin, zeaxanthin, chlorophyll b) and microscopy-based cell counts were used as indicators of phytoplankton growth. In March, the phytoplankton community was dominated by Gyrodinium instriatum and only fucoxanthin-based growth rates were stimulated by nitrogen addition. The limited response to nitrogen suggests other factors may control phytoplankton growth and community composition in early spring. In June, inorganic nitrogen concentrations were low and stimulatory effects of both nitrogen forms were observed for chlorophyll a- and diagnostic photopigment-based growth rates. In contrast, cell counts showed that only cryptophyte and dinoflagellate (Heterocapsa rotundata) growth were stimulated. Responses of other photopigments may have been due to an increase in pigment per cell or growth of plankton too small to be counted with the microscopic methods used. Despite high nitrate concentrations in August, growth rates were elevated in response to urea and/or nitrate addition for all photopigments except peridinin. However, this response was not observed in cell counts, again suggesting that pigment-based growth responses may not always be indicative of a true community and/or taxa-specific growth response. This highlights the need to employ targeted microscopy-based cell enumeration concurrent with pigment-based technology to facilitate a more complete understanding of phytoplankton dynamics in estuarine systems. These results are consistent with previous studies showing the seasonal importance of nitrogen availability in estuaries, and also

  19. Effects of Nitrogen Availability and Form on Phytoplankton Growth in a Eutrophied Estuary (Neuse River Estuary, NC, USA).

    PubMed

    Cira, Emily K; Paerl, Hans W; Wetz, Michael S

    2016-01-01

    Nitrogen availability and form are important controls on estuarine phytoplankton growth. This study experimentally determined the influence of urea and nitrate additions on phytoplankton growth throughout the growing season (March 2012, June 2011, August 2011) in a temperate, eutrophied estuary (Neuse River Estuary, North Carolina, USA). Photopigments (chlorophyll a and diagnostic photopigments: peridinin, fucoxanthin, alloxanthin, zeaxanthin, chlorophyll b) and microscopy-based cell counts were used as indicators of phytoplankton growth. In March, the phytoplankton community was dominated by Gyrodinium instriatum and only fucoxanthin-based growth rates were stimulated by nitrogen addition. The limited response to nitrogen suggests other factors may control phytoplankton growth and community composition in early spring. In June, inorganic nitrogen concentrations were low and stimulatory effects of both nitrogen forms were observed for chlorophyll a- and diagnostic photopigment-based growth rates. In contrast, cell counts showed that only cryptophyte and dinoflagellate (Heterocapsa rotundata) growth were stimulated. Responses of other photopigments may have been due to an increase in pigment per cell or growth of plankton too small to be counted with the microscopic methods used. Despite high nitrate concentrations in August, growth rates were elevated in response to urea and/or nitrate addition for all photopigments except peridinin. However, this response was not observed in cell counts, again suggesting that pigment-based growth responses may not always be indicative of a true community and/or taxa-specific growth response. This highlights the need to employ targeted microscopy-based cell enumeration concurrent with pigment-based technology to facilitate a more complete understanding of phytoplankton dynamics in estuarine systems. These results are consistent with previous studies showing the seasonal importance of nitrogen availability in estuaries, and also

  20. Sediment discharge into a subsiding Louisiana deltaic estuary through a Mississippi River diversion

    USGS Publications Warehouse

    Snedden, G.A.; Cable, J.E.; Swarzenski, C.; Swenson, E.

    2007-01-01

    Wetlands of the Mississippi River deltaic plain in southeast Louisiana have been hydrologically isolated from the Mississippi River by containment levees for nearly a century. The ensuing lack of fluvial sediment inputs, combined with natural submergence processes, has contributed to high coastal land loss rates. Controlled river diversions have since been constructed to reconnect the marshes of the deltaic plain with the river. This study examines the impact of a pulsed diversion management plan on sediment discharge into the Breton Sound estuary, in which duplicate 185 m3 s-1-diversions lasting two weeks each were conducted in the spring of 2002 and 2003. Sediment delivery during each pulse was highly variable (11,300-43,800 metric tons), and was greatest during rising limbs of Mississippi River flood events. Overland flow, a necessary transport mechanism for river sediments to reach the subsiding backmarsh regions, was induced only when diversion discharge exceeded 100 m3 s-1. These results indicate that timing and magnitude of diversion events are both important factors governing marsh sediment deposition in the receiving basins of river diversions. Though the diversion serves as the primary source of river sediments to the estuary, the inputs observed here were several orders of magnitude less than historical sediment discharge through crevasses and uncontrolled diversions in the region, and are insufficient to offset present rates of relative sea level rise. ?? 2006 Elsevier Ltd. All rights reserved.

  1. Sediment dynamics in the lower Mekong River: Transition from tidal river to estuary

    NASA Astrophysics Data System (ADS)

    Nowacki, Daniel J.; Ogston, Andrea S.; Nittrouer, Charles A.; Fricke, Aaron T.; Van, Pham Dang Tri

    2015-09-01

    A better understanding of flow and sediment dynamics in the lowermost portions of large-tropical rivers is essential to constraining estimates of worldwide sediment delivery to the ocean. Flow velocity, salinity, and suspended-sediment concentration were measured for 25 h at three cross sections in the tidal Song Hau distributary of the Mekong River, Vietnam. Two campaigns took place during comparatively high-seasonal and low-seasonal discharge, and estuarine conditions varied dramatically between them. The system transitioned from a tidal river with ephemeral presence of a salt wedge during high flow to a partially mixed estuary during low flow. The changing freshwater input, sediment sources, and estuarine characteristics resulted in seaward sediment export during high flow and landward import during low flow. The Dinh An channel of the Song Hau distributary exported sediment to the coast at a rate of about 1 t s-1 during high flow and imported sediment in a spatially varying manner at approximately 0.3 t s-1 during low flow. Scaling these values results in a yearly Mekong sediment discharge estimate about 65% smaller than a generally accepted estimate of 110 Mt yr-1, although the limited temporal and spatial nature of this study implies a relatively high degree of uncertainty for the new estimate. Fluvial advection of sediment was primarily responsible for the high-flow sediment export. Exchange-flow and tidal processes, including local resuspension, were principally responsible for the low-flow import. The resulting bed-sediment grain size was coarser and more variable during high flow and finer during low, and the residual flow patterns support the maintenance of mid-channel islands. This article was corrected on 7 OCT 2015. See the end of the full text for details.

  2. Historic Habitat Opportunities and Food-Web Linkages of Juvenile Salmon in the Columbia River Estuary, Annual Report of Research.

    SciTech Connect

    Bottom, Daniel L.; Simenstad, Charles A.; Campbell, Lance

    2009-05-15

    In 2002 with support from the U.S. Army Corps of Engineers (USACE), an interagency research team began investigating salmon life histories and habitat use in the lower Columbia River estuary to fill significant data gaps about the estuary's potential role in salmon decline and recovery . The Bonneville Power Administration (BPA) provided additional funding in 2004 to reconstruct historical changes in estuarine habitat opportunities and food web linkages of Columbia River salmon (Onchorhynchus spp.). Together these studies constitute the estuary's first comprehensive investigation of shallow-water habitats, including selected emergent, forested, and scrub-shrub wetlands. Among other findings, this research documented the importance of wetlands as nursery areas for juvenile salmon; quantified historical changes in the amounts and distributions of diverse habitat types in the lower estuary; documented estuarine residence times, ranging from weeks to months for many juvenile Chinook salmon (O. tshawytscha); and provided new evidence that contemporary salmonid food webs are supported disproportionately by wetland-derived prey resources. The results of these lower-estuary investigations also raised many new questions about habitat functions, historical habitat distributions, and salmon life histories in other areas of the Columbia River estuary that have not been adequately investigated. For example, quantitative estimates of historical habitat changes are available only for the lower 75 km of the estuary, although tidal influence extends 217 km upriver to Bonneville Dam. Because the otolith techniques used to reconstruct salmon life histories rely on detection of a chemical signature (strontium) for salt water, the estuarine residency information we have collected to date applies only to the lower 30 or 35 km of the estuary, where fish first encounter ocean water. We lack information about salmon habitat use, life histories, and growth within the long tidal

  3. Sedimentology and ichnology of the fluvial reach to inner estuary of the Ogeechee River estuary, Georgia, USA

    NASA Astrophysics Data System (ADS)

    Shchepetkina, Alina; Gingras, Murray K.; Pemberton, S. George

    2016-08-01

    Through the integration of sedimentological and ichnological observations, this paper explores the character of sediments deposited across the fluvio-tidal transition zone of the upper microtidal, mixed-energy, sand-dominated Ogeechee River estuary, Georgia, USA. A transect of tidally influenced to fluvial channel-bars and their facies variability is reported. Field and laboratory methods were employed, including observation of physical and biogenic sedimentary structures on the point-bar surfaces and in trenches, collection of grab samples, suction and box coring, grain size and total organic carbon analyses, optical microscopy, core logging, and daylight photography. The data presented in the paper can help in predicting facies changes across the fluvio-tidal transition of sand-dominated fluvio-tidal deposits in the rock record. The lower inner estuary is characterized by medium-fine and fine-medium sand with planar and trough cross-bedding, small-scale ripple lamination, tidal sedimentary structures (flaser and wavy bedding, herringbone cross-stratification), abundant organic debris, and mud rip-up clasts. Bioturbation of the intertidal point bars is low, but cryptobioturbation is locally observed. Upper inner estuary deposits comprise coarse-medium- and medium-coarse-grained sand, and are characterized by faint high-angle planar and trough cross-bedding. Organic debris, mud rip-up clasts, herringbone and current-ripple lamination are rarely observed. Bioturbation is absent to sparse. The fluvio-tidal transition is represented by very-coarse- to coarse-grained sand and granules. Physical sedimentary structures constitute massive, graded planar and trough cross-bedding with abundant plant detritus. Except for rare Siphonichnus- and Lockeia-like traces, bioturbation is absent. The fluvial setting is characterized by coarse-medium sand with unidirectional cross-bedding, current-ripple lamination, and rare organic-rich mud clasts. Bioturbation is absent. Inner

  4. Evaluating Cumulative Ecosystem Response to Restoration Projects in the Columbia River Estuary, Annual Report 2006

    SciTech Connect

    Johnson, Gary E.; Borde, Amy B.; Dawley, Earl; Diefenderfer, Heida L.; Ebberts, Blaine D.; Putman, Douglas A.; Roegner, G. C.; Thom, Ronald M.; Vavrinec, John; Whiting, Allan H.

    2007-12-06

    This report is the third annual report of a six-year project to evaluate the cumulative effects of habitat restoration action in the Columbia River Estuary (CRE). The project is being conducted for the U.S. Army Corps of Engineers (Corps) by the Marine Sciences Laboratory of the Pacific Northwest National Laboratory, the Pt. Adams Biological Field Station of the National Marine Fisheries Service, and the Columbia River Estuary Study Taskforce. Measurement of the cumulative effects of ecological restoration projects in the Columbia River estuary is a formidable task because of the size and complexity of the estuarine landscape and the meta-populations of salmonids in the Columbia River basin. Despite the challenges presented by this system, developing and implementing appropriate indicators and methods to measure cumulative effects is the best way to enable estuary managers to track the overall effectiveness of investments in estuarine restoration projects. This project is developing methods to quantify the cumulative effects of multiple restoration activities in the CRE. The overall objectives of the 2006 study were to continue to develop techniques to assess cumulative effects, refine the standard monitoring protocols, and initiate development of an adaptive management system for Corps of Engineers’ habitat restoration monitoring efforts in the CRE. (The adaptive management effort will be reported at a later date.) Field studies during 2006 were conducted in tidal freshwater at Kandoll Farm on the lower Grays River and tidal brackish water at Vera Slough on Youngs Bay. Within each of area, we sampled one natural reference site and one restoration site. We addressed the overall objectives with field work in 2006 that, coupled with previous field data, had specific objectives and resulted in some important findings that are summarized here by chapter in this report. Each chapter of the report contains data on particular monitored variables for pre- and post

  5. Detection of Changes in Sediment Distribution in the Hudson River Estuary with Repeated Subbottom Profiling

    NASA Astrophysics Data System (ADS)

    Nitsche, F. O.; Kenna, T. C.

    2014-12-01

    During the last decade, several major storms have impacted the US Atlantic coast, including tropical storm Sandy in 2013 and tropical storms Irene and Lee in 2012. These storms, in particular, had major impacts on the watershed of the Hudson River Estuary, resulting in changes in the delivery and distribution of sediments. While Sandy generated a large storm surge that mostly effected the lower estuary, Irene and Lee caused significant flooding in the upper estuary that delivered ~2.7 million tons of sediment to the Hudson River Estuary, which according to USGS estimates is an amount equal to three times the annual load of ~700,000-800,000 metric? tons (Wall et al. 2008; Ralston et al., 2013). Here we report results from high-resolution Chirp subbottom surveys conducted in selected areas of the Hudson River in 2014. Areas were selected with the goal of investigating changes in the sediment deposition and storage in the Hudson River as a result of these events. The new survey lines were acquired following the tracks of earlier subbottom profiles that were collected as part of the Hudson River Benthic Mapping Project in the early 2000s, i.e. before the storms of 2012 and 2013, in a dense grid of subbottom profiles. We then compared these co-located profiles to determine changes between the profiles and to map out the spatial distribution of increased deposition in the selected areas. In several places, the data show clear increases of the thickness of depositional layers of over 0.25 m while in other areas these changes are less clear. Changes based on sub-bottom data will be compared to results obtained on sediment cores taken from the same areas. Preliminary analysis of the sediment cores indicates clear layers of recent sediments in some areas that correspond to the results of the subbottom analysis.

  6. Distribution characteristics of transparent exopolymer particles in the Pearl River estuary, China

    NASA Astrophysics Data System (ADS)

    Sun, Cui-Ci; Wang, You-Shao; Li, Qian P.; Yue, Wei-Zhong; Wang, Yu-Tu; Sun, Fu-Lin; Peng, Ya-Lan

    2012-12-01

    Distribution of Transparent Exopolymer Particles (TEP) in the Pearl River estuary, China, was investigated during two cruises in August 2009 and January 2010. TEPcolor concentrations were 521.5-1727.4 μg Xeq.L-1 (μg Gum Xanthan equivalent liter-1) in August 2009 and 88.7-1586.9 μg Xeq.L-1 in January 2010, respectively. The size of TEP generally increased in the seaward along the longitudinal section with the dominant size of 2-40 μm during the cruises. Experimental work suggested that both concentration and size of TEP increased with Ca2+ concentration (from 0.8 mmol L-1 to 10 mmol L-1). In the field study, Ca2+ concentration had a positive correlation with TEPcolor concentration in the surface layer with salinity <16. Decrease of TEP concentration seaward from intermediary salinity was partly due to dilution of seawater as well as enhanced aggregation and sedimentation of TEP via increasing divalent cation concentration. TEP concentration and turbidity maximum coexisted at the tip of salt wedge in the bottom layer during the wet season, and positive correlation between TEP and turbidity was observed in the winter. Relationships between TEP and turbidity suggested the important contribution of TEP aggregation to flocculation and sedimentation of particles in estuaries. Different pattern of TEP during two cruises can be attributed to physical process (i.e., mixing type) in estuaries. These findings indicated that formation and distribution of TEP were largely influenced by interaction between physical and biogeochemical processes in the Pearl River estuary. A conceptual model for TEP formation and distribution in the Pearl River estuary was developed.

  7. Coastal Upwelling Supplies Oxygen-Depleted Water to the Columbia River Estuary

    PubMed Central

    Roegner, G. Curtis; Needoba, Joseph A.; Baptista, António M.

    2011-01-01

    Low dissolved oxygen (DO) is a common feature of many estuarine and shallow-water environments, and is often attributed to anthropogenic nutrient enrichment from terrestrial-fluvial pathways. However, recent events in the U.S. Pacific Northwest have highlighted that wind-forced upwelling can cause naturally occurring low DO water to move onto the continental shelf, leading to mortalities of benthic fish and invertebrates. Coastal estuaries in the Pacific Northwest are strongly linked to ocean forcings, and here we report observations on the spatial and temporal patterns of oxygen concentration in the Columbia River estuary. Hydrographic measurements were made from transect (spatial survey) or anchor station (temporal survey) deployments over a variety of wind stresses and tidal states during the upwelling seasons of 2006 through 2008. During this period, biologically stressful levels of dissolved oxygen were observed to enter the Columbia River estuary from oceanic sources, with minimum values close to the hypoxic threshold of 2.0 mg L−1. Riverine water was consistently normoxic. Upwelling wind stress controlled the timing and magnitude of low DO events, while tidal-modulated estuarine circulation patterns influenced the spatial extent and duration of exposure to low DO water. Strong upwelling during neap tides produced the largest impact on the estuary. The observed oxygen concentrations likely had deleterious behavioral and physiological consequences for migrating juvenile salmon and benthic crabs. Based on a wind-forced supply mechanism, low DO events are probably common to the Columbia River and other regional estuaries and if conditions on the shelf deteriorate further, as observations and models predict, Pacific Northwest estuarine habitats could experience a decrease in environmental quality. PMID:21533083

  8. Evaluation of Cumulative Ecosystem Response to Restoration Projects in the Lower Columbia River and Estuary, 2010

    SciTech Connect

    Johnson, Gary E.; Diefenderfer, Heida L.; Thom, Ronald M.; Roegner, G. Curtis; Ebberts, Blaine D.; Skalski, John R.; Borde, Amy B.; Dawley, Earl; Coleman, Andre M.; Woodruff, Dana L.; Breithaupt, Stephen A.; Cameron, April; Corbett, C.; Donley, Erin E.; Jay, D. A.; Ke, Yinghai; Leffler, K.; McNeil, C.; Studebaker, Cindy; Tagestad, Jerry D.

    2012-05-01

    This is the seventh and final annual report of a project (2004–2010) addressing evaluation of the cumulative effects of habitat restoration actions in the 235-km-long lower Columbia River and estuary. The project, called the Cumulative Effects (CE) study, was conducted for the U.S. Army Corps of Engineers Portland District by a collaboration of research agencies led by the Pacific Northwest National Laboratory. We achieved the primary goal of the CE study to develop a methodology to evaluate the cumulative effects of habitat actions in the Columbia Estuary Ecosystem Restoration Program. We delivered 1) standard monitoring protocols and methods to prioritize monitoring activities; 2) the theoretical and empirical basis for a CE methodology using levels-of-evidence; 3) evaluations of cumulative effects using ecological relationships, geo-referenced data, hydrodynamic modeling, and meta-analyses; and 4) an adaptive management process to coordinate and coalesce restoration efforts in the LCRE. A solid foundation has been laid for future comprehensive evaluations of progress made by the Columbia Estuary Ecosystem Restoration Program to understand, conserve, and restore ecosystems in the lower Columbia River and estuary.

  9. Inventories and sorption-desorption trends of radiocesium and radiocobalt in James River estuary sediments

    SciTech Connect

    Zucker, C.L.; Olsen, C.R.; Larsen, I.L.; Cutshall, N.H.

    1984-01-01

    Anthropogenic radionuclides (Cs TX, Cs TU, CoW) have been introduced to the James River estuary as a result of low-level releases from the Surry Reactor site since 1973 and worldwide atmospheric fallout from nuclear weapons tests since the early 1950s. The total radionuclide burden in the estuary sediments has been estimated by integrating radionuclide activities in 29 box cores and extrapolating these integrated values over surface areas subdivided on the basis of sediment type, rate of accumulation, and proximity to the reactor release site. The results indicate that 30% of the CoW, but only 15% of the Cs TU released from the reactor site, has been retained in the estuary sediments, and about 40% of the Cs TU and CoW sediment inventory is in areas that represent less than 5% of the total estuarine surface area. Depletion of the Cs TU in downstream sediments forms a noticeable trend in the James River estuary, and it is postulated that seawater cation competition and exchange is primarily responsible. 26 references, 1 figure, 4 tables.

  10. Radionuclide tracers for the fate of metals in the Savannah estuary: River-ocean exchange processes

    SciTech Connect

    Olsen, C.R.; Thein, M.; Larsen, I.L.; Byrd, J.T.; Windom, H.L.

    1989-01-01

    Plutonium-238 from the US Department of Energy's Savannah River Plant labels riverborne particles, providing a unique opportunity for examining the fate of metals in estuaries and for tracing river-ocean exchange processes. Results indicate that plutonium and lead-210 are enriched on estuarine particles and that inputs of plutonium from oceanic sources greatly exceed inputs from riverborne or drainage-basin sources as far upstream as the landward limit of seawater penetration. We suggest that these radionuclides (and other chemically reactive metals) are being scavenged from oceanic water by sorption onto particles in turbid estuarine and coastal areas. Since estuaries, bays, mangroves, and intertidal areas serve as effective traps for fine particles and associated trace substances, these results have important implications concerning the disposal of chemically reactive substances in oceanic waters. 13 refs., 1 fig., 1 tab.

  11. The partitioning of Triclosan between aqueous and particulate bound phases in the Hudson River Estuary.

    PubMed

    Wilson, Brittan; Chen, Robert F; Cantwell, Mark; Gontz, Allen; Zhu, Jun; Olsen, Curtis R

    2009-01-01

    The distribution of Triclosan within the Hudson River Estuary can be explained by a balance among the overall effluent inputs from municipal sewage treatment facilities, dilution of Triclosan concentrations in the water column with freshwater and seawater inputs, removal of Triclosan from the water column by adsorption to particles, and loss to photodegradation. This study shows that an average water column concentration of 3+/-2 ng/l (in the lower Hudson River Estuary) is consistent with an estimate for dilution of average wastewater concentrations with seawater and calculated rates of adsorption of Triclosan to particles. An average Triclosan sediment concentration of 26+/-11 ng/g would be in equilibrium with the overlying water column if Triclosan has a particle-to-water partitioning coefficient of k(d) approximately 10(4), consistent with laboratory estimates. PMID:19559448

  12. Benthic foraminiferal assemblages and trace metals reveal the environment outside the Pearl River Estuary.

    PubMed

    Li, Tao; Xiang, Rong; Li, Tuanjie

    2013-10-15

    We investigated the distribution patterns of the benthic foraminiferal assemblages outside the Pearl River Estuary in relation to trace metals, organic carbon and sedimentary particle fractions. The study area is unpolluted to moderately polluted by Cr, Cu, Pb and Zn and is completely polluted by Ni. The highest levels are found in the western coastal zone. Spatial distributions of the measured elements are strongly related to the behavior of the sedimentary clay fraction. The analyses of species abundance and community diversity as well as subsequent canonical correspondence analysis were used to reveal the relationship between foraminifera data and environmental parameters. Four sampling site groups established by factor analysis were distributed from the coastal area to the inner shelf. Their distribution patterns have a strong correlation with Cu, Pb and Ba. This research shows that benthic foraminifera can be used as bioindicators of trace metal pollutants outside the Pearl River Estuary. PMID:23972678

  13. Metals in fish from the Upper Benue River and lakes Geriyo and Njuwa in northeastern Nigeria

    SciTech Connect

    Eromosele, C.O.; Eromosele, I.C.; Muktar, S.L.M.; Birdling, S.A.

    1995-01-01

    Lakes Geriyo and Njuwa occupy natural depressions near the upper Benue River in northeastern Nigeria. The lakes are flooded by the river during the rainy season spanning the months of May to September. Fishing activities on the lakes and river provide fish for consumption by the local communities. Industrial activity around the upper Benue River and the lakes is low and there is no information on other activities with the potential for polluting the Benue River as it flows from neighboring Cameroon. However, an unconfirmed report indicated high levels of lead in the upper Benue River, generally speculated as arising from biogeometrical factors. Trace elements, some of which are toxic, may accumulate in edible marine organisms to levels which may be deleterious to human health. For the upper Benue River and its associate lakes, Geriyo and Njuwa, there is yet no report of a systematic study to assess the levels of metals in fish found in these waters. This paper presents the results of a study on metal levels in fish collected from Lakes Geriyo and Njuwa and upper Benue River in northeastern Nigeria. 7 refs., 1 fig., 2 tabs.

  14. Density-salinity-suspended sediment experimental curves for Guadalquivir River estuary conditions

    NASA Astrophysics Data System (ADS)

    Carpintero García, M.; Jurado López, A.; Contreras Arribas, E.; Polo Gómez, M. J.

    2012-04-01

    Estuarine water in Mediterranean watersheds contains high suspended sediment concentrations due to both the fine textured nature of the materials reaching the final stretch of the fluvial network, and the agricultural predominance of soil uses upstream. Saline conditions induce flocculation processes which alter the original behavior of the soil particles in water. The final high density mixture of water-salts-sediments has physicochemical characteristics very different from the saline water alone. However, this is not often included when modeling the dynamics of estuaries, adopting the density, viscosity, etc., values corresponding to the present level of salinity found at each point. The nature of the local sediments influences the density values finally found. The Guadalquivir River estuary (southwestern Spain) extends along the 105 km between the Alcalá del Río dam, upstream, and its mouth in Sanlúcar de Barrameda. It is an Atlantic mesotidal estuary (Díez-Minguito et al., 2010) with a mainly longitudinal salinity gradient. The sediments in the estuary are very fine-textured due to the great length of the river and, mainly, the extreme trapping efficiency of the dense reservoir network upstream along the 57400 km2 of the contributing area. With an average value of 0.5 - 4.5 g L-1 for the suspended sediment range along the estuary, extreme values up to 160 g L-1 can be found associated with persistent turbidity events forced by different combinations of conditions. This work shows the density variation with changing bivariate conditions of salinity-suspended sediments, following the combined range found along the estuary. Laboratory measurements were made at 19° C for synthetic seawater with 35 g L-1salinity and the decreasing range found upstream by dilution until a final value of 0.2 g L-1, for which an increasing suspended sediment concentration (SSC) was induced by adding sediments locally extracted from the estuary. The final density of these sets of

  15. Multi-Scale Action Effectiveness Research in the Lower Columbia River and Estuary, 2012

    SciTech Connect

    Johnson, Gary E.; Sather, Nichole K.; Storch, Adam; Johnson, Jeff; Skalski, J. R.; Teel, D. J.; Brewer, Taylor; Bryson, Amanda J.; Dawley, Earl M.; Kuligowski, D. R.; Whitesel, T.; Mallette, Christine

    2013-11-30

    The study reported herein was conducted for the U.S. Army Corps of Engineers, Portland District (USACE) by researchers at the Pacific Northwest National Laboratory (PNNL), Oregon Department of Fish and Wildlife (ODFW), National Marine Fisheries Service (NMFS), University of Washington (UW), and U.S. Fish and Wildlife Service (USFWS). The goal of the study was to evaluate the ecological benefits of restoration actions for juvenile salmon in the lower Columbia River and estuary (LCRE; rkm 0–234).

  16. Vertical geochemical distribution of some contaminants in estuarine sediments from the Jaboatão River, Pernambuco, Northeastern Brazil.

    NASA Astrophysics Data System (ADS)

    Lima, Marta; Neumann, Virgínio; Castro, Maria Teresa; Lima, Enjôlras; Lima, Edmilson; Silva, Ricardo

    2014-05-01

    Sediment core samples with length ranging from 50 cm was collected in the Jaboatão river estuary and analyzed to ( As, Cr, Pb, Hg, Ni and Zn) level concentrations using instrumental neutron activation analysis (INAA). The studied area is located in the northeastern coast of Pernambuco State and is comprised of a densely urbanized region, the largest industrial complex of the state, with a predominance of fertilizer plants. These elements have a consistent vertical evolution compatible with the increase of the pelitic-organic material. There is an increase from bottom to top of the core but this may not represent a real increase in the input, but rather a concentration associated to the fine particle fraction and organic matter that increases to the top of the core profile. These conditions of clay predominance in estuarine sediments on the top indicate a decrease of the energy condition in the system and not necessarily an increase in the supply of contaminating metals. The majority of the chemical species, the concentration did not reach toxicity levels, when considering the values (ERL and ERM) established by USEPA (1998). The only exception is Cr, which has already surpassed the ERM value, and suggests that this increase is related to industrial contribution. Chromium concentration reached preliminary alert levels according to international environmental agencies, whereas the other species analyzed do not show toxicity. Key-words: environmental geochemistry, estuarine sediments

  17. The geochemistry of rare earth elements in the Amazon River estuary

    SciTech Connect

    Shokovitz, E.R. )

    1993-05-01

    The estuarine geochemistry of rare earth elements (REEs) was studied using samples collected in the Amazon River estuary from the AmasSeds (Amazon Shelf SEDiment Study) cruise of August 1989. Extensive removal of dissolved (0.22 [mu]m filtered) trivalent REEs from river water occurs in the low (0--6) salinity region. Removal by the salt-induced coagulation of river colloids leads to fractionation among the REE(III) series; the order of removal is light REEs > middle REEs > heavy REEs. There also is the enhanced removal of Ce (relative to trivalent La and Nd) in the low salinity (0--6) zone and in the zone of high biological activity. This is the first field observation of strong Ce removal associated with coagulation of river colloids and biological productivity. The argument is made that the decrease in the Ce anomaly across a biological front is caused by biologically mediated oxidation of Ce(III) to Ce(IV). Coagulation of river colloids and biologically mediated oxidation of Ce(III) lead to fractionation of REE(III) and redox modification of Ce. These processes result in the REE composition becoming fractionated relative to the Amazon River water and crust and more evolved toward the REE composition of the oceans. This study implies that reactions in estuaries play significant, yet poorly understood roles in controlling the REE composition and Ce anomaly of the oceans. 46 refs., 9 figs., 2 tabs.

  18. Distribution, sources and ecological risk assessment of PAHs in surface sediments from the Luan River Estuary, China.

    PubMed

    Zhang, Daolai; Liu, Jinqing; Jiang, Xuejun; Cao, Ke; Yin, Ping; Zhang, Xunhua

    2016-01-15

    The distribution, sources and risk assessment of 16 polycyclic aromatic hydrocarbons (PAHs) of surface sediments in the Luan River Estuary, China, have been investigated in the research. The results indicated that the total concentrations of 16 PAHs in surface sediments of the Luan River Estuary ranged from 5.1 to 545.1 ng g(-1)dw with a mean value of 120.8 ng g(-1)dw, which is relatively low in comparison with other estuaries around the world. The PAHs in the study area were mainly originated from pyrogenic sources. Besides, PAHs may be contaminated by petrogenic PAHs as indicated by the selected ratios of PAHs, the 2-tailed Pearson correlation analysis and principal components analysis at different sites. The result of the ecological risk assessment shows little negative effect for most individual PAHs in surface sediments of the Luan River Estuary, China. PMID:26616744

  19. [Ecological risk assessment of organophosphorus pesticides in aquatic ecosystems of Pearl River Estuary].

    PubMed

    Guo, Qiang; Tian, Hui; Mao, Xiao-Xuan; Huang, Tao; Gao, Hong; Ma, Jian-Min; Wu, Jun-Nian

    2014-03-01

    The risk quotient method and a probabilistic risk assessment method were applied for assessing aquatic ecological risk of nine organophosphorus pesticides, including thimet, dichlorovos, disulfoton, dimethoate, dimethyl parathion, chlorpyrifos, ethoprophos, sumithion and malathion on eight aquatic organisms in the Pearl River Estuary. Results using the risk quotient method revealed that the risk level of opossum shrimp was the highest among eight aquatic organisms of the Pearl River Estuary. The risk of water flea and midge was in medium level, followed by the rest six aquatic organisms, including diatom, oyster, carp, catfish and eel, which were in the low risk by the examined organophosphorus pesticides. It was found that thimet made the largest contribution to total aquatic ecological risk among nine organophosphorus pesticides to every organism. The results from probabilistic risk assessment showed that the total ecological risk in high water period was higher than that in low water period determined by the HC5 under the 95% confidence level. The largest contribution of thimet to total aquatic ecological risk subject to the HC5 in 50% confidence level was regarded as the toxic reference value. The probabilistic risk of a single contaminant showed that thimet and disulfoton were harmful to exceeded 10% organisms in the estuarine. The probabilistic risk of nine pesticides mixture in high water period was also higher than that in low water period, and both risks were greater than 5% which exceeded safety threshold for 95% organisms in the Pearl River Estuary. PMID:24881393

  20. Lower Columbia River and Estuary Habitat Monitoring Study, 2011 - Final Report

    SciTech Connect

    Borde, Amy B.; Kaufmann, Ronald M.; Cullinan, Valerie I.; Zimmerman, Shon A.; Thom, Ronald M.; Wright, Cynthia L.

    2012-03-22

    The Ecosystem Monitoring Program is a collaborative effort between the Lower Columbia River Estuary Partnership (LCREP), University of Washington, Wetland Ecosystem Team (UW), US Geological Survey, Water Science Center (USGS), National Oceanic and Atmospheric Administration, National Marine Fisheries Service (NOAA-Fisheries, hereafter NOAA), and Pacific Northwest National Laboratory, Marine Sciences Laboratory (PNNL). The goal of the program is to conduct emergent wetland monitoring aimed at characterizing salmonid habitats in the lower Columbia River and estuary (LCRE) from the mouth of the estuary to Bonneville Dam (Figure 1). This is an ecosystem based monitoring program focused on evaluating status and trends in habitat and reducing uncertainties regarding these ecosystems to ultimately improve the survival of juvenile salmonids through the LCRE. This project comprehensively assesses habitat, fish, food web, and abiotic conditions in the lower river, focusing on shallow water and vegetated habitats used by juvenile salmonids for feeding, rearing and refugia. The information is intended to be used to guide management actions associated with species recovery, particularly that of threatened and endangered salmonids. PNNL’s role in this multi-year study is to monitor the habitat structure (e.g., vegetation, topography, channel morphology, and sediment type) as well as hydrologic patterns.

  1. Distribution and abundance of American eels in the White Oak River estuary, North Carolina

    USGS Publications Warehouse

    Hightower, J.E.; Nesnow, C.

    2006-01-01

    Apparent widespread declines in abundance of Anguilla rostrata (American eel) have reinforced the need for information regarding its life history and status. We used commercial eel pots and crab (peeler) pots to examine the distribution, condition, and abundance of American eels within the White Oak River estuary, NC, during summers of 2002-2003. Catch of American eels per overnight set was 0.35 (SE = 0.045) in 2002 and 0.49 (SE = 0.044) in 2003. There was not a significant linear relationship between catch per set and depth in 2002 (P = 0.31, depth range 0.9-3.4 m) or 2003 (P = 0.18, depth range 0.6-3.4 m). American eels from the White Oak River were in good condition, based on the slope of a length-weight relationship (3.41) compared to the median slope (3.15) from other systems. Estimates of population density from grid sampling in 2003 (300 mm and larger: 4.0-13.8 per ha) were similar to estimates for the Hudson River estuary, but substantially less than estimates from other (smaller) systems including tidal creeks within estuaries. Density estimates from coastal waters can be used with harvest records to examine whether overfishing has contributed to the recent apparent declines in American eel abundance.

  2. Terrestrial humic substances in Daliao River and its estuary: optical signatures and photoreactivity to UVA light.

    PubMed

    Chen, Hao; Lei, Kun; Wang, Xuechun

    2016-04-01

    Fluorescent dissolved organic matter (FDOM) components were identified by Parallel Factor Analysis (PARAFAC) in surface water of Daliao River and its estuary with a focus on terrestrial humic substance-(HS)-like FDOM identified under two contrasting hydrological conditions. The hydrological conditions did not have noticeable effect on the spectral features of the terrestrial HS-like FDOM, but did affect the components' intensities and photoreactivity: (1) the intensities of terrestrial HS-like components were higher in the normal flow period than in the high flow period, and (2) a spectrally similar terrestrial HS-like FDOM identified under the two contrasting hydrological conditions showed distinct photoreactivity to the same dose of UVA illumination. The findings indicated that terrestrial HS was generated at lower intensities at the terrestrial sources during the high flow period than during the normal flow period and that the transport of terrestrial HS material through the river-estuary system was affected dominantly by seawater dilution along the salinity gradient while fine-tuned by solar UVA illumination. This study exemplifies the effect of hydrological conditions on optical signatures of terrestrial HS-like FDOM and their photoreactivity towards UVA illumination, improving our understanding of the dynamics of terrestrial HS material in river-estuary systems in the framework of the currently proposed new conceptual model for terrestrial organic matter. PMID:26627698

  3. Effects of river discharge and tidal asymmetry on residual sediment transport and long-term morphodynamics in the river estuary

    NASA Astrophysics Data System (ADS)

    Guo, L.; Van der Wegen, M.; Roelvink, J.; He, Q.

    2013-12-01

    The morphodynamics are of ubiquitous importance to the estuarine function with respect to navigation and ecology. This study examines the hydrodynamics, residual sediment transport processes and long-term morphodynamics in the river estuary forced by river discharge and marine tides. We systematically investigated the generation of tidal asymmetry and its modulation by varying river discharges, the interactions between the river discharge and the tides, and the induced residual sediment transport and associated morphodynamic adjustment and then the feedback mechanisms by deploying the Delft3D model in 1D mode. The model shows that the internally generated tidal asymmetry behaves nonlinearly with increasing river discharge. The internal tidal asymmetry is flood dominated in the absence of river discharge and tidal flat. Introduction of a river discharge promotes the overtide generation which reinforces the tidal asymmetry. An increasing river discharge dissipates the tidal energy and damps the tides that the overtide generation is confined in the downstream. A river discharge threshed can be figured out at which the energy transformation from the principle tide (M2) to the overtide (M4) reaches maximum. The tidal averaged residual sediment transport is decomposed into components according to a bed load transport mode. The tidal asymmetry induces a residual sediment transport whose direction is determined by the nature of the tidal asymmetry. The river discharge induces a net seaward residual transport due to enhanced seaward residual current. Moreover, the interaction between the river discharge and tides generates a river-induced asymmetry. The river-induced asymmetry enhances the seaward residual sediment transport to a large degree that it plays a significant role in flushing sediment seaward. The estuarine morphodynamics reach a (quasi-) equilibrium in a time scale of millennia. The morphodynamic equilibrium is characterized by a reducing longitudinal residual

  4. Trace metals in the Ob and Yenisei Rivers' Estuaries (the Kara Sea).

    NASA Astrophysics Data System (ADS)

    Demina, L. L.

    2014-12-01

    Behavior of some trace metals (Al, As, Cd, Co, Cr, Cu, Fe, Mn, Ni and Pb) in water column (soluble <0.45 µm and particulate fractions) and bottom sediments (surface and cores) along the two transects from the Ob River and Yenisei River Estuaries to the Kara Sea was studied. The length of both transects was about 700 km. Water depth was 12-63 m, O2 dissolved :5.36-9.55 ml l-1. Along the transects salinity increased from 0.07 to 34.2 psu, while the SPM' concentration decreased from 10.31 to 0.31 mg/l. Total suspended particulate matter load is more than one order of magnitude higher in the Ob River Estuary comparing to that of the Yenisei River. It has led to a significant difference between the suspended trace metals' concentrations (µg/l) in water of the two estuaries. With salinity increase along transects Fe susp., Mn susp. and Zn susp. decreased by a factor of 100-500, that has led to a growth of a relative portion of dissolved trace metals followed by their bioaccumulation (Demina et al., 2010). A strong direct correlation between suspended Cu, Fe and SPM mass concentration was found. For the first time along the Yenisei River' Estuary -the Kara Sea transect a direct positive correlation between Cu suspended and volume concentration of SPM (mg/ml3) was found, that was attributed to contribution of phytoplankton aggregates in the SPM composition. A trend of relationship between content of suspended As and pelitic fraction (2-10 µm) of SPM was firstly found in theses basins also. Study of trace metal speciation in the bottom sediments (adsorbed, associated with Fe-Mn (oxyhydr)oxides, organic matter and fixed in the mineral lattice or refractory) has revealed the refractory fraction to be prevailing (70-95% total content) for Fe, Zn, Cu, Co, Ni, Cr, Cd and Pb. That means that toxic heavy metals were not available for bottom fauna. Mn was predominantly found in the adsorbed and (oxyhydr)oxides geochemically labile forms, reflecting the redox condition change

  5. A dynamic water-quality modeling framework for the Neuse River estuary, North Carolina

    USGS Publications Warehouse

    Bales, Jerad D.; Robbins, Jeanne C.

    1999-01-01

    As a result of fish kills in the Neuse River estuary in 1995, nutrient reduction strategies were developed for point and nonpoint sources in the basin. However, because of the interannual variability in the natural system and the resulting complex hydrologic-nutrient inter- actions, it is difficult to detect through a short-term observational program the effects of management activities on Neuse River estuary water quality and aquatic health. A properly constructed water-quality model can be used to evaluate some of the potential effects of manage- ment actions on estuarine water quality. Such a model can be used to predict estuarine response to present and proposed nutrient strategies under the same set of meteorological and hydrologic conditions, thus removing the vagaries of weather and streamflow from the analysis. A two-dimensional, laterally averaged hydrodynamic and water-quality modeling framework was developed for the Neuse River estuary by using previously collected data. Development of the modeling framework consisted of (1) computational grid development, (2) assembly of data for model boundary conditions and model testing, (3) selection of initial values of model parameters, and (4) limited model testing. The model domain extends from Streets Ferry to Oriental, N.C., includes seven lateral embayments that have continual exchange with the main- stem of the estuary, three point-source discharges, and three tributary streams. Thirty-five computational segments represent the mainstem of the estuary, and the entire framework contains a total of 60 computa- tional segments. Each computational cell is 0.5 meter thick; segment lengths range from 500 meters to 7,125 meters. Data that were used to develop the modeling framework were collected during March through October 1991 and represent the most comprehensive data set available prior to 1997. Most of the data were collected by the North Carolina Division of Water Quality, the University of North Carolina

  6. Migratory Behavior and Survival of Juvenile Salmonids in the Lower Columbia River and Estuary in 2009

    SciTech Connect

    McMichael, Geoffrey A.; Harnish, Ryan A.; Bellgraph, Brian J.; Carter, Jessica A.; Ham, Kenneth D.; Titzler, P. Scott; Hughes, Michael S.

    2010-08-01

    The study reported herein was funded as part of the Anadromous Fish Evaluation Program, which is managed by the U.S. Army Corps of Engineers (USACE). The Anadromous Fish Evaluation Program study code is EST P 02 01: A Study of Salmonid Survival and Behavior through the Columbia River Estuary Using Acoustic Tags. The study was conducted by the Pacific Northwest National Laboratory (PNNL) and National Oceanic and Atmospheric Administration (NOAA) Fisheries for the USACE Portland District. Estimated survival of acoustic-tagged juvenile Chinook salmon and steelhead through the lower Columbia River and estuary in 2009 was lowest in the final 50 km of the estuary. Probability of survival was relatively high (>0.90) for yearling and subyearling Chinook salmon from the Bonneville Dam forebay (rkm 236) to Three-tree Point (rkm 49.6). Survival of juvenile Chinook salmon declined sharply through the lower 50 km of the estuary. Acoustic-tagged steelhead smolts did not survive as well as juvenile Chinook salmon between Bonneville Dam and the mouth of the Columbia River. Steelhead survival began to decline farther upstream (at rkm 86) relative to that of the Chinook salmon stocks. Subyearling Chinook salmon survival decreased markedly as the season progressed. It remains to be determined whether later migrating subyearling Chinook salmon are suffering increasing mortality as the season progresses or whether some portion of the apparent loss is due to fish extending their freshwater residence. This study provided the first glimpse into what promises to be a very informative way to learn more about how juvenile salmonid passage experiences through the FCRPS may influence their subsequent survival after passing Bonneville Dam. New information regarding the influence of migration pathway through the lower 50 km of the Columbia River estuary on probability of survival of juvenile salmonids, combined with increased understanding regarding the foraging distances and time periods of

  7. Artificial water sediment regulation scheme influences morphology, hydrodynamics and nutrient behavior in the Yellow River estuary

    NASA Astrophysics Data System (ADS)

    Xu, Bochao; Yang, Disong; Burnett, William C.; Ran, Xiangbin; Yu, Zhigang; Gao, Maosheng; Diao, Shaobo; Jiang, Xueyan

    2016-08-01

    Anthropogenic controls on water and sediment may play important roles in river system transformations and morphological evolution, which could further affect coastal hydrodynamics and nutrient behavior. We used geochemical tracers to evaluate the influence of an intentional large release of water and sediment during the so-called "Water Sediment Regulation Scheme" (WSRS) on estuarine morphology, hydrodynamics and nutrients in the Yellow River estuary, China. We discovered that there was a newly formed small delta in the river mouth after the 2013 WSRS. This new morphologic feature altered terrestrial material distribution patterns from a single plume to a two-plume pattern within the estuary. Our results show that the WSRS significantly influenced the study area in the following ways: (1) Radium and nutrient concentrations were significantly elevated (two to four times), especially along the two river outlets. (2) Estuarine mixing was about two times stronger during WSRS than before. Average aerial mixing rates before and during WSRS were 50 ± 26 km2 d-1 and 89 ± 51 km2 d-1, respectively. (3) Our data is consistent with P limitation and suggest that stoichiometrically based P limitation was even more severe during WSRS. (4) All river-derived nutrients were thoroughly consumed within one to two weeks after entry to near-shore waters. (5) The extent of the area influenced by terrestrial nutrients was two to three times greater during WSRS. Human influence, such as triggered by WSRS regulations, should thus be considered when studying biogeochemical processes and nutrient budgets in situations like the Yellow River estuary.

  8. Endocrine disruption in Sphoeroides testudineus tissues and sediments highlights contamination in a northeastern Brazilian estuary.

    PubMed

    Pimentel, Marcionília Fernandes; Damasceno, Évila Pinheiro; Jimenez, Paula Christine; Araújo, Pedro Filipe Ribeiro; Bezerra, Marcielly Freitas; de Morais, Pollyana Cristina Vasconcelos; Cavalcante, Rivelino Martins; Loureiro, Susana; Lotufo, Letícia Veras Costa

    2016-05-01

    In recent decades, considerable attention has been devoted to endocrine disruptor chemicals (EDC) and studies on fish feminization have increased throughout the years as a key signal for aquatic environmental contamination. The input of domestic sewage into water reservoirs is common in South American countries, especially in cities that experienced rapid population growths and unplanned urbanization. This study aimed at characterizing morphofunctional parameters of the tropical fish Sphoeroides testudineus and investigating the potential occurrence and effects of endocrine disruptors in the Pacoti River (Ceará, Brazil), often considered a reference site. After collection from the field, fish were measure/weighted and desiccated for gender identification (males, females, and undifferentiated), gonadal histology, and vitellogenin expression. From the biometric analysis, undifferentiated fish showed lower weight and length than female and male fish, although no differences in the condition index were observed. The gonadal weight of undifferentiated fish was significantly lower than those of females and males. Although this pattern was observed, gonadosomatic index (GSI) showed a different pattern, with differences being observed just between males and the other two groups (females and undifferentiated). Vitellogenin (VTG) expression was detected in many mature male and undifferentiated fish, indicating endocrine disruption. In addition, several EDCs (estrone, 17α-estradiol, 17β-estradiol, 17α-ethinylestradiol, diethylstilbestrol, and estriol) were identified and quantified in sediments from the sampling site. These results were unexpected and indicative that the Pacoti River is impaired by estrogenic contamination. PMID:27094055

  9. Silurian geology of the Des Plaines River Valley, northeastern Illinois

    NASA Astrophysics Data System (ADS)

    Mikulic, D. G.; Sargent, M. L.; Norby, R. D.; Kolata, D. R.

    Silurian dolomites are among the most poorly understood rock units in the midwestern United States. These rocks have not attracted as much interest as those in other Paleozoic systems for several reasons. Destruction of primary fabric by dolomitization discourages sedimentological studies, carbonate buildups complicate local correlations. However, the development of large, deep quarries has advanced the understanding of the lithostratigraphy of Silurian rocks, particularly in northeastern Illinois, where the growth of the Chicago area has supported a large stone industry for the last 150 years. This field trip provides a good overview of Chicago-area Silurian geology.

  10. Sedimentary fabrics of the macrotidal, mud-dominated, inner estuary to fluvio-tidal transition zone, Petitcodiac River estuary, New Brunswick, Canada

    NASA Astrophysics Data System (ADS)

    Shchepetkina, Alina; Gingras, Murray K.; Zonneveld, John-Paul; Pemberton, S. George

    2016-03-01

    The study provides a detailed description of mud-dominated sedimentary fabrics and their application for the rock record within the inner estuary to the fluvial zone of the Petitcodiac River estuary, New Brunswick, Canada. Sedimentological characteristics and facies distributions of the clay- and silt-rich deposits are reported. The inner estuary is characterized by thick accumulations of interbedded silt and silty clay on intertidal banks that flank the tidally influenced channel. The most common sedimentary structures observed are parallel and wavy lamination, small-scale soft-sediment deformation with microfaults, and clay and silt current ripples. The tidal channel contains sandy silt and clayey silt with planar lamination, massive and convolute bedding. The fluvio-tidal transition zone is represented by interbedded trough cross-stratified sand and gravel beds with planar laminated to massive silty mud. The riverine, non-tidal reach of the estuary is characterized by massive, planar tabular and trough cross-stratified gravel-bed deposits. The absence of bioturbation within the inner estuary to the fluvio-tidal transition zone can be explained by the following factors: low water salinities (0-5 ppt), amplified tide and current speeds, and high concentrations of flocculated material in the water body. Notably, downstream in the middle and outer estuary, bioturbation is seasonally pervasive: in those locales the sedimentary conditions are similar, but salinity is higher. In this study, the sedimentological (i.e., grain size, bedding characters, sedimentary structures) differences between the tidal estuary and the fluvial setting are substantial, and those changes occur over only a few hundred meters. This suggests that the widely used concept of an extensive fluvio-tidal transition zone and its depositional character may not be a geographically significant component of fluvial or estuary deposits, which can go unnoticed in the study of the ancient rocks.

  11. Restoration of Hydrodynamic and Hydrologic Processes in the Chinook River Estuary, Washington – Feasibility Assessment

    SciTech Connect

    Khangaonkar, Tarang P.; Breithaupt, Stephen A.; Kristanovich, Felix C.

    2006-01-01

    A hydrodynamic and hydrologic modeling analysis was conducted to evaluate the feasibility of restoring natural estuarine functions and tidal marine wetlands habitat in the Chinook River estuary, located near the mouth of the Columbia River in Washington. The reduction in salmonid populations is attributable primarily to the construction of a Highway 101 overpass across the mouth of the Chinook River in the early 1920s with a tide gate under the overpass. This construction, which was designed to eliminate tidal action in the estuary, has impeded the upstream passage of salmonids. The goal of the Chinook River Restoration Project is to restore tidal functions through the estuary, by removing the tide gate at the mouth of the river, filling drainage ditches, restoring tidal swales, and reforesting riparian areas. The hydrologic model (HEC-HMS) was used to compute Chinook River and tributary inflows for use as input to the hydrodynamic model at the project area boundary. The hydrodynamic model (RMA-10) was used to generate information on water levels, velocities, salinity, and inundation during both normal tides and 100-year storm conditions under existing conditions and under the restoration alternatives. The RMA-10 model was extended well upstream of the normal tidal flats into the watershed domain to correctly simulate flooding anddrainage with tidal effects included, using the wetting and drying schemes. The major conclusion of the hydrologic and hydrodynamic modeling study was that restoration of the tidal functions in the Chinook River estuary would be feasible through opening or removal of the tide gate. Implementation of the preferred alternative (removal of the tide gate, restoration of the channel under Hwy 101 to a 200-foot width, and construction of an internal levee inside the project area) would provide the required restorations benefits (inundation, habitat, velocities, and salinity penetration, etc.) and meet flood protection requirements. The

  12. Restoration of Hydrodynamic and Hydrologic Processes in the Chinook River Estuary, Washington – Feasibility Assessment

    SciTech Connect

    Khangaonkar, Tarang P.; Breithaupt, Stephen A.; Kristanovich, Felix C.

    2006-08-03

    A hydrodynamic and hydrologic modeling analysis was conducted to evaluate the feasibility of restoring natural estuarine functions and tidal marine wetlands habitat in the Chinook River estuary, located near the mouth of the Columbia River in Washington. The reduction in salmonid populations is attributable primarily to the construction of a Highway 101 overpass across the mouth of the Chinook River in the early 1920s with a tide gate under the overpass. This construction, which was designed to eliminate tidal action in the estuary, has impeded the upstream passage of salmonids. The goal of the Chinook River Restoration Project is to restore tidal functions through the estuary, by removing the tide gate at the mouth of the river, filling drainage ditches, restoring tidal swales, and reforesting riparian areas. The hydrologic model (HEC-HMS) was used to compute Chinook River and tributary inflows for use as input to the hydrodynamic model at the project area boundary. The hydrodynamic model (RMA-10) was used to generate information on water levels, velocities, salinity, and inundation during both normal tides and 100-year storm conditions under existing conditions and under the restoration alternatives. The RMA-10 model was extended well upstream of the normal tidal flats into the watershed domain to correctly simulate flooding and drainage with tidal effects included, using the wetting and drying schemes. The major conclusion of the hydrologic and hydrodynamic modeling study was that restoration of the tidal functions in the Chinook River estuary would be feasible through opening or removal of the tide gate. Implementation of the preferred alternative (removal of the tide gate, restoration of the channel under Hwy 101 to a 200-foot width, and construction of an internal levee inside the project area) would provide the required restorations benefits (inundation, habitat, velocities, and salinity penetration, etc.) and meet flood protection requirements. The

  13. Dissolved silica in the tidal Potomac River and Estuary, 1979-81 water years

    USGS Publications Warehouse

    Blanchard, Stephen F.

    1988-01-01

    The Potomac River at Chain Bridge is the major riverine source of dissolved silica (DSi) to the tidal Potomac River and Estuary. DSi concentrations at Chain Bridge are positively correlated with river discharge; river discharge is an important factor controlling rates of supply, dilution, and residence time. When river flow is high, the longitudinal DSi distribution is conservative. When river flow is low, other processes, such as phytoplankton uptake, benthic flux, resuspension, ground-water discharge, and water-column dissolution of diatoms, tend to be more influential than the river. Elevated concentrations of DSi in sewage-treatment-plant effluent in the Washington, D.C., area raise the DSi concentration of receiving Potomac River water. The tidal river zone serves as a net sink for DSi as a result of phytoplankton uptake. Ultimately, the biogenic silica from the tidal river is transported to the transition zone, where it is mineralized. As a result, the DSi concentration in the transition zone increases during summer. The DSi concentrations in the estuarine zone are largely controlled by dilution by Chesapeake Bay water and by phytoplankton uptake.

  14. Contrasting Inherent Optical Properties and Carbon Metabolism Between Five Northeastern (USA) Estuary-plume Systems

    NASA Technical Reports Server (NTRS)

    Vandemark, Doug; Salisbury, Joe; Hunt, Chris; McGillis, Wade R.

    2004-01-01

    We have recently developed the ability to rapidly assess Surface inherent optical properties (IOP), oxygen concentration and pCO2 in estuarine-plume systems using flow-through instrumentation. During the summer of 2004, several estuarine-plume systems were surveyed which include the Pleasant (ME), Penobscot (ME), Kennebec-Androscoggin (ME), Merrimack (NH-MA) and Hudson (NY). Continuous measurements of surface chlorophyll and colored dissolved organic carbon (CDOM) fluorescence, beam attenuation, temperature, salinity, oxygen and pC02 were taken at each system along a salinity gradient from fresh water to near oceanic endmembers. CTD and IOP profiles were also taken at predetermined surface salinity intervals. These were accompanied by discrete determinations of chlorophyll (HPLC and fluorometric), total suspended solids (TSS), dissolved organic carbon (DOC) and alkalinity. IOP data were calibrated using chlorophyll, DOC and TSS data to enable the retrieval of these constituents from IOP data. Considerable differences in the data sets were observed between systems. These ranged from the DOC-enriched, strongly heterotrophic Pleasant River System to the high-chlorophyll autotrophic Merrimack River System. Using pCO2 and oxygen saturation measurements as proxies for water column metabolism, distinct relationships were found between trophic status and inherent optical properties. The nature of these relationships varies between systems and is likely a function of watershed and estuarine attributes including carbon and nutrient loading, in-situ production and related autochthonous inputs of DOC and alkalinity. Our results suggest that IOP data may contain significant information about the trophic status of estuarine and plume systems.

  15. Integrated Database Construction for Efficient Support of Yeongsan River Estuary Management System

    NASA Astrophysics Data System (ADS)

    Lee, G. H.; Kim, K. H.; Lee, S. J.

    2014-02-01

    Yeongsan River is one of the four major rivers in South Korea, and it flows toward the Yellow Sea by passing through Damyang and Gwangju. In particular, the skewness of the main stream in Yeongsan River is relatively higher compared to other rivers. Accordingly, flood damage occurred frequently due to the flooding of sea water during tidal periods. Additionally, the environment of the estuary in Yeongsan River has been severely damaged due to indiscreet development and the inflow of various waste waters. Therefore, water quality improvement and management are crucial. For better water quality management, the government ministry is collecting various data from different fields to identify the water quality conditions. The necessity of collected data is being heightened in order to apply them into the estuary management system. However, in terms of the observed data, the observed field or items frequently modified according to social interests. Additionally, index is needed in order to search for massive amount of observation data. Due to this, the process of construction into database is relatively difficult. Therefore, in this study, these characteristics were considered for construction into the integrated DB.

  16. Seasonal variations in the nitrogen isotopic composition of dissolved nitrate in the Changjiang River estuary, China

    NASA Astrophysics Data System (ADS)

    Yu, Haiyan; Yu, Zhiming; Song, Xiuxian; Cao, Xihua; Yuan, Yongquan; Lu, Guangyuan

    2015-03-01

    The Changjiang River estuary is the most eutrophic estuary in China. Although anthropogenic input from the Changjiang River (the third-largest river in the world) is considered the main source of nitrogen, the contributions of newly regenerated nitrogen from deep waters may be underestimated, in part due to the lack of information on the nitrogen biogeochemical processes that are occurring. The nitrogen stable isotope ratio is widely used as an indicator of the source of nitrogen and nitrogen transformation processes including assimilation, nitrification, nitrogen fixation and mineralization. To study the biogeochemical processes in the Changjiang River estuary, seasonal variations in the nitrogen stable isotope ratio of nitrate (δ15NO3), salinity, temperature, dissolved oxygen concentration, chlorophyll a (Chl a) concentration, and the composition of dissolved inorganic nitrogen were investigated along two transects in the estuary in 2010. In the surface waters, assimilation between May and November was suggested by high Chl a and δ15NO3 and supported by the mixing behavior of the nitrate and δ15NO3. From February to November, the mean nitrate content in the deep waters gradually increased (from ∼8 to ∼15 μmol l-1), whereas the mean δ15NO3 decreased (from ∼2‰ to ∼-2‰). Particularly in November, most of the δ15NO3 values in the deep waters were negative (∼-5‰ -0‰, which is much lower than the ∼3‰ riverine input from δ15NO3), indicating that most of the nitrates in the deep water were newly regenerated from nitrification rather than originating from riverine input. Additionally, the mean ammonium abruptly increased (from ∼2 to ∼20 μmol l-1) in the deep waters during November when the δ15NO3 values were negative, whereas in August, high Chl a values were observed in the deep waters. These results indicate that remineralization and nitrification occurred in the deep waters of the Changjiang River estuary, implying that regenerated

  17. Bathymetric controls on sediment transport in the Hudson River estuary: Lateral asymmetry and frontal trapping

    NASA Astrophysics Data System (ADS)

    Ralston, David K.; Geyer, W. Rockwell; Warner, John C.

    2012-10-01

    Analyses of field observations and numerical model results have identified that sediment transport in the Hudson River estuary is laterally segregated between channel and shoals, features frontal trapping at multiple locations along the estuary, and varies significantly over the spring-neap tidal cycle. Lateral gradients in depth, and therefore baroclinic pressure gradient and stratification, control the lateral distribution of sediment transport. Within the saline estuary, sediment fluxes are strongly landward in the channel and seaward on the shoals. At multiple locations, bottom salinity fronts form at bathymetric transitions in width or depth. Sediment convergences near the fronts create local maxima in suspended-sediment concentration and deposition, providing a general mechanism for creation of secondary estuarine turbidity maxima at bathymetric transitions. The lateral bathymetry also affects the spring-neap cycle of sediment suspension and deposition. In regions with broad, shallow shoals, the shoals are erosional and the channel is depositional during neap tides, with the opposite pattern during spring tides. Narrower, deeper shoals are depositional during neaps and erosional during springs. In each case, the lateral transfer is from regions of higher to lower bed stress, and depends on the elevation of the pycnocline relative to the bed. Collectively, the results indicate that lateral and along-channel gradients in bathymetry and thus stratification, bed stress, and sediment flux lead to an unsteady, heterogeneous distribution of sediment transport and trapping along the estuary rather than trapping solely at a turbidity maximum at the limit of the salinity intrusion.

  18. Advective pore water input of nutrients to the Satilla River Estuary, Georgia, USA

    NASA Astrophysics Data System (ADS)

    Jahnke, R. A.; Alexander, C. R.; Kostka, J. E.

    2003-03-01

    In situ benthic flux measurements, pore water nutrient profiles, water column nutrient distributions, sediment grain size distributions and side-scan sonar observations suggest that advective transport of pore waters may be a major input pathway of nutrients into the Satilla River Estuary (coastal Georgia, USA). In situ benthic chamber incubations demonstrate the occurrence of highly variable, but occasionally very large sea floor fluxes of silicate, phosphate, and ammonium. Locally occurring benthic microbial mineralization of organic matter, as estimated by S 35-sulphate reduction rate measurements, is insufficient to support these large fluxes. We hypothesize that the observed interlayering of permeable, sandy sediments with fine-grained, organic-rich sediments in the estuary provides conduits for advective transport of pore water constituents out of the sediments. Because permeable layers may extend significant distances beneath the salt marsh, the large fluxes observed may be supported by remineralization occurring over large areas adjacent to the estuary. Advective transport may be induced by pressure gradients generated by a variety of processes, including landward recharge by meteoric or rain waters if sand layers extend far enough into the maritime coastal lands. Alternatively, tidal variations across the salt marsh sediment surface may hydraulically pump water through the sediment system. Because these fluxes appear to be concentrated into small layers, this source may be a significant input of nutrients to the estuary even if permeable, sandy layers comprise a very small proportion of the seabed.

  19. Data-collection program for Pamlico River Estuary model calibration and validation

    USGS Publications Warehouse

    Bales, Jerad D.

    1989-01-01

    An investigation is being conducted to collect and interpret continuous records relating to the flow characteristics of the Pamlico River Estuary, North Carolina, and to calibrate and validate a numerical model of estuarine hydrodynamics. The study reach is 50 kilometers long and ranges in width from 330 meters at the upstream boundary to 6.4 kilometers at the downstream end. Water levels are recorded at 6 locations along the estuary; daily water-level range is typically greater at the head of the estuary than at the mouth, most likely due to upstream narrowing of the channel. Water-quality data are recorded at 14 locations. These data indicate that saline waters with low dissolved oxygen concentrations move upstream along the bottom of the estuary. Point velocities were monitored for 3 weeks at 7 locations; vertical profiles of horizontal velocity were made at the boundaries of the study reach for about 32 hours. Local tributary inflows and wind speed and direction are also being determined.

  20. Bathymetric controls on sediment transport in the Hudson River estuary: Lateral asymmetry and frontal trapping

    USGS Publications Warehouse

    Ralston, David K.; Geyer, W. Rockwell; Warner, John C.

    2012-01-01

    Analyses of field observations and numerical model results have identified that sediment transport in the Hudson River estuary is laterally segregated between channel and shoals, features frontal trapping at multiple locations along the estuary, and varies significantly over the spring-neap tidal cycle. Lateral gradients in depth, and therefore baroclinic pressure gradient and stratification, control the lateral distribution of sediment transport. Within the saline estuary, sediment fluxes are strongly landward in the channel and seaward on the shoals. At multiple locations, bottom salinity fronts form at bathymetric transitions in width or depth. Sediment convergences near the fronts create local maxima in suspended-sediment concentration and deposition, providing a general mechanism for creation of secondary estuarine turbidity maxima at bathymetric transitions. The lateral bathymetry also affects the spring-neap cycle of sediment suspension and deposition. In regions with broad, shallow shoals, the shoals are erosional and the channel is depositional during neap tides, with the opposite pattern during spring tides. Narrower, deeper shoals are depositional during neaps and erosional during springs. In each case, the lateral transfer is from regions of higher to lower bed stress, and depends on the elevation of the pycnocline relative to the bed. Collectively, the results indicate that lateral and along-channel gradients in bathymetry and thus stratification, bed stress, and sediment flux lead to an unsteady, heterogeneous distribution of sediment transport and trapping along the estuary rather than trapping solely at a turbidity maximum at the limit of the salinity intrusion.

  1. Foraging patterns of Caspian terns and double-crested cormorants in the Columbia River estuary

    USGS Publications Warehouse

    Lyons, Donald E.; Roby, D.D.; Collis, K.

    2007-01-01

    We examined spatial and temporal foraging patterns of Caspian terns and double-crested cormorants nesting in the Columbia River estuary, to potentially identify circumstances where juvenile salmonids listed under the U.S. Endangered Species Act might be more vulnerable to predation by these avian piscivores. Data were collected during the 1998 and 1999 breeding seasons, using point count surveys of foraging birds at 40 sites along the river's banks, and using aerial strip transect counts throughout the estuary for terns. In 1998, terns selected tidal flats and sites with roosting beaches nearby for foraging, making greater use of the marine/mixing zone of the estuary later in the season, particularly areas near the ocean jetties. In 1999, cormorants selected foraging sites in freshwater along the main channel with pile dikes present, particularly early in the season. Foraging trends in the other year for each species were generally similar to the above but usually not significant. During aerial surveys we observed 50% of foraging and commuting terns within 8 km of the Rice Island colony, and ??? 5% of activity occurred ??? 27 km from this colony in both years. Disproportionately greater cormorant foraging activity at pile dikes may indicate greater vulnerability of salmonids to predation at those features. Colony relocations to sites at sufficient distance from areas of relatively high salmonid abundance may be a straightforward means of reducing impacts of avian predation on salmonids than habitat alterations within the Columbia River estuary, at least for terns. ?? 2007 by the Northwest Scientific Association. All rights reserved.

  2. Turning the tide: effects of river inflow and tidal amplitude on sandy estuaries in laboratory landscape experiments

    NASA Astrophysics Data System (ADS)

    Kleinhans, Maarten; Braat, Lisanne; Leuven, Jasper; Baar, Anne; van der Vegt, Maarten; van Maarseveen, Marcel; Markies, Henk; Roosendaal, Chris; van Eijk, Arjan

    2016-04-01

    Many estuaries formed over the Holocene through a combination of fluvial and coastal influxes, but how estuary planform shape and size depend on tides, wave climate and river influxes remains unclear. Here we use a novel tidal flume setup of 20 m length by 3 m width, the Metronome (http://www.uu.nl/metronome), to create estuaries and explore a parameter space for the simple initial condition of a straight river in sandy substrate. Tidal currents capable of transporting sediment in both the ebb and flood phase because they are caused by periodic tilting of the flume rather than the classic method of water level fluctuation. Particle imaging velocimetry and a 1D shallow flow model demonstrate that this principle leads to similar sediment mobility as in nature. Ten landscape experiments recorded by timelapse overhead imaging and AGIsoft DEMs of the final bed elevation show that absence of river inflow leads to short tidal basins whereas even a minor discharge leads to long convergent estuaries. Estuary width and length as well as morphological time scale over thousands of tidal cycles strongly depend on tidal current amplitude. Paddle-generated waves subdue the ebb delta causing stronger tidal currents in the basin. Bar length-width ratios in estuaries are slightly larger to those in braided rivers in experiments and nature. Mutually evasive ebb- and flood-dominated channels are ubiquitous and appear to be formed by an instability mechanism with growing bar and bifurcation asymmetry. Future experiments will include mud flats and live vegetation.

  3. Salinity and flow relations and effects of reduced flow in the Chassahowitzka River and Homosassa River estuaries, southwest Florida

    USGS Publications Warehouse

    Yobbi, D.K.; Knochenmus, L.A.

    1989-01-01

    The Chassahowitzka and Homosassa Rivers Florida, are spring-fed streams flowing into the Gulf of Mexico that may be affected by future development of groundwaters. Reduction of streamflow may cause an upstream movement of saltwater in the rivers. Data on flow, tide, and salinity define the physical characteristics of both estuaries. Vertical and longitudinal salinity profiles indicate that the estuaries are reasonably well mixed for the streamflow and high-tide conditions observed during the study. Estimates of the daily maximum upstream locations of the vertically averaged 3-ppt and 5-ppt salinities in the Chassahowitzka River and the vertically averaged 2-ppt and 5-ppt salinities in the Homosassa River are described by multiple linear regression analysis using daily mean streamflow of each river and high-tide stage of the gulf. For the vertically averaged 3-ppt and 2-ppt salinities, the square of the correlation coefficient for the predictive equations ranged from 0.77 to 0.85. For the vertically averaged 5-ppt salinities, the square of the correlation coefficient for the predictive equations ranged from 0.73 to 0.88. Upstream movement of salt-water due to pumping 40 million gal/day from a well field near the headwater springs of the Chassahowitzka and Homosassa Rivers was determined. Pumping at this rate from the Chassahowitzka River would cause a 15% reduction of average spring flow, resulting in an upstream movement of both the vertically averaged 3-ppt and 5-ppt of about 0.3 mile. In the Homosassa River, pumping would cause a 13% reduction of average spring flow, resulting in an upstream movement of both the vertically averaged 2-ppt and 5-ppt salinities of about 0.1 mile. (USGS)

  4. Immunological responses of the mangrove oysters Crassostrea gasar naturally infected by Perkinsus sp. in the Mamanguape Estuary, Paraíba state (Northeastern, Brazil).

    PubMed

    Queiroga, Fernando Ramos; Marques-Santos, Luis Fernando; Hégaret, Hélène; Soudant, Philippe; Farias, Natanael Dantas; Schlindwein, Aline Daiane; Mirella da Silva, Patricia

    2013-08-01

    Perkinsus genus includes protozoan parasites of marine mollusks, especially bivalves. In the last four years, this parasite has been detected in mangrove oysters Crassostrea rhizophorae and Crassostrea gasar from the Northeastern region of Brazil. Hemocytes are the key cells of the oyster immune system, being responsible for a variety of cellular and humoral reactions, such as phagocytosis, encapsulation and the release of several effector molecules that control the invasion and proliferation of microorganisms. In Brazil, there is little information on perkinsosis and none on the immune responses of native oysters' species against Perkinsus spp. The objective of this study was to determine the effects of natural infection by Perkinsus sp. on the immunological parameters of mangrove oysters C. gasar cultured in the Mamanguape River Estuary (Paraíba, Brazil). Adults oysters (N = 40/month) were sampled in December 2011, March, May, August and October 2012. Gills were removed and used to determine the presence and intensity of the Perkinsus sp. infection, according to a scale of four levels (1-4), using the Ray's fluid thioglycollate medium assay. Immunological parameters were measured in hemolymph samples by flow cytometry, including: total hemocyte count (THC), differential hemocyte count (DHC), cell mortality, phagocytic capacity, and production of Reactive Oxygen Species (ROS). The plasma was used to determine the hemagglutination activity. The results showed the occurrence of Perkinsus sp. with the highest mean prevalence (93.3%) seen so far in oyster populations in Brazil. Despite that, no oyster mortality was associated. In contrast, we observed an increase in hemocyte mortality and a suppression of two of the main defense mechanisms, phagocytosis and ROS production in infected oysters. The increase in the percentage of blast-like cells on the hemolymph, and the increase in THC in oysters heavily infected (at the maximum intensity, 4) suggest an induction of

  5. Effects of Spartina alterniflora invasion on soil respiration in the Yangtze River estuary, China.

    PubMed

    Bu, Naishun; Qu, Junfeng; Li, Zhaolei; Li, Gang; Zhao, Hua; Zhao, Bin; Li, Bo; Chen, Jiakuan; Fang, Changming

    2015-01-01

    Many studies have found that plant invasion can enhance soil organic carbon (SOC) pools, by increasing net primary production (NPP) and/or decreased soil respiration. While most studies have focused on C input, little attention has been paid to plant invasion effects on soil respiration, especially in wetland ecosystems. Our study examined the effects of Spartina alterniflora invasion on soil respiration and C dynamics in the Yangtze River estuary. The estuary was originally occupied by two native plant species: Phragmites australis in the high tide zone and Scirpus mariqueter in the low tide zone. Mean soil respiration rates were 185.8 and 142.3 mg CO2 m(-2) h(-1) in S. alterniflora and P. australis stands in the high tide zone, and 159.7 and 112.0 mg CO2 m(-2) h(-1) in S. alterniflora and S. mariqueter stands in the low tide zone, respectively. Aboveground NPP (ANPP), SOC, and microbial biomass were also significantly higher in the S. alterniflora stands than in the two native plant stands. S. alterniflora invasion did not significantly change soil inorganic carbon or pH. Our results indicated that enhanced ANPP by S. alterniflora exceeded invasion-induced C loss through soil respiration. This suggests that S. alterniflora invasion into the Yangtze River estuary could strengthen the net C sink of wetlands in the context of global climate change. PMID:25799512

  6. An integrated model for the fate and bioaccumulation of PCBs in the Hudson River estuary

    SciTech Connect

    Farley, K.J.; Thomann, R.V.

    1995-12-31

    An integrated mass transport model with a five component food chain calculation was developed for predicting PCB accumulation in sediments, lower trophic species, and striped bass. The model was originally applied to PCB homologues and calibrated using field data through 1987. Results of this work indicated that, under a no-action alternative, 50% of the striped bass would be below the FDA limit of 2 {micro}g of PCB/g of fish (wet weight) by 1992 and 95% of the striped bass would be below the FDA limit by 2004. An initial post-audit evaluation of the model showed that predicted PCB concentrations in striped bass compared well to field measurements. Some deviation in predicted and observed concentrations however were noted in the upper portion of the estuary and are believed to be related to a transient PCB load from the upper Hudson. Further evaluations are presently being performed to addressed: (1) how have Hudson River sediments and striped bass responded to decreasing PCB loads; (2) what are the relative contributions of PCB loads from the upper Hudson, from contaminated estuarine sediments, and from wastewater discharges into the lower estuary on present PCB levels in fish; and (3) what role does congener structure play in determining the fate and bioaccumulation of PCBs in the Hudson River estuary.

  7. Fouling community of the Loxahatchee River estuary, Florida, 1980-81

    USGS Publications Warehouse

    McPherson, B.F.; Sonntag, W.H.; Sabanskas, M.

    1984-01-01

    Monthly growth of the fouling community at eight test panel sites in the Loxahatchee River Estuary was related to salinity and temperature. Growth was lowest in January 1981 (averaging 23 g per m2, dry weight), and increased during spring and early summer with increasing water temperature. Maximum growth occurred during early or midsummer at upstream locations, before river or canal discharge substantially reduced salinity, and in late summer at downstream locations. Growth was greatest at salinities slightly less than that of seawater and decreased at salinities less than about 10???. Growth was suppressed throughout the estuary in August 1981, probably because of the sudden decrease in temperature and salinity, and perhaps the increase in physical scouring, caused by runoff from Tropical Storm Dennis. Large loads of nutrients transported to the estuary from storm runoff, however, may have subsequently stimulated growth, which increased in September 1981 to the maximum for the year (averaging 683 g per m2, dry weight). ?? 1984 Estuarine Research Federation.

  8. Tidally Induced Changes in Bacterial Growth and Viability in the Macrotidal Han River Estuary, Yellow Sea

    NASA Astrophysics Data System (ADS)

    Hyun, J.-H.; Choi, J. K.; Chung, K. H.; Yang, E.-J.; Kim, M.-K.

    1999-02-01

    The Han River estuary in the Yellow Sea is a macrotidal (tidal range of 3·5 m at neap tide and 8·0 m at spring tide) eutrophic environment. Changes in bacterial growth and viability at different NaCl concentrations as well as other physico-chemical environmental parameters were investigated at different tidal levels in order to elucidate the major environmental factors controlling the bacterial community. Bacterial growth rates (μ) varied with tidal state; maximum (μ=0·159 h -1) at high tide, and minimum (μ=0·069 h -1) at low tide. Although bacteria play a substantial role in ammonia removal and regeneration, growth was not controlled by the fluctuations of nutrient concentrations in the high nutrient estuary. The low viable cell number recorded with the increased NaCl concentration indicated that the salinity changes with tidal state was a major environmental factor controlling the viability of the freshwater bacterial populations. Portions of freshwater bacterial CFU (colony forming units) during low tide accounted for approximately 30% of the total CFU, and decreased down to 10% during high tide. Overall, the results indicate that the microbial communities in the macrotidal Han River estuary can be divided into two distinct groups according to the variations in salinity and freshwater runoff: (1) autochthonous halotolerant estuarine populations which are nourished by the high nutrient runoff; and (2) allochthonous halophobic freshwater populations which are adversely affected by salinity increase.

  9. Copper cycling in the Patuxent River estuary and condenser micro-fouling studies

    SciTech Connect

    Eaton, A.; Chamberlain, C.

    1982-01-01

    This report describes the methods and results of a study of copper cycling in the Patuxent River estuary. The study focused on detailed sampling of the water column over a number of seasons to determine: (1) the amount of excess copper in the estuary which may be attributable to corrosion of condenser tubes at the Chalk Point Power Plant; (2) the geographic distribution of excess copper in the estuary, (3) the forms of excess copper, and (4) the fate of added copper. Extensive sampling was performed including sampling above and below the pycnocline, sampling in cross channel transects and resampling stations at different tidal stages to establish short term variability. Estimates for the amount of excess copper in the Patuxent are derived and the potential impact of that excess is assessed. This report also presents the results of studies of micro-fouling processes in power plant condensers employing once-through cooling. The studies entailed: (1) the isolation and characterization of 38 bacterial isolates from effluents and condenser tubes of the Crane Power Plant which is located on Saltpeter Creek, approximately ten miles northeast of Baltimore, Maryland and the Chalk Point Power Plant on the Patuxent River, (2) laboratory experiments on colonization rates using pure cultures at high nutrient levels, and (3) growth studies on the joint influence of copper and nutrient levels.

  10. Effects of Spartina alterniflora Invasion on Soil Respiration in the Yangtze River Estuary, China

    PubMed Central

    Bu, Naishun; Qu, Junfeng; Li, Zhaolei; Li, Gang; Zhao, Hua; Zhao, Bin; Li, Bo; Chen, Jiakuan; Fang, Changming

    2015-01-01

    Many studies have found that plant invasion can enhance soil organic carbon (SOC) pools, by increasing net primary production (NPP) and/or decreased soil respiration. While most studies have focused on C input, little attention has been paid to plant invasion effects on soil respiration, especially in wetland ecosystems. Our study examined the effects of Spartina alterniflora invasion on soil respiration and C dynamics in the Yangtze River estuary. The estuary was originally occupied by two native plant species: Phragmites australis in the high tide zone and Scirpus mariqueter in the low tide zone. Mean soil respiration rates were 185.8 and 142.3 mg CO2 m−2 h−1 in S. alterniflora and P. australis stands in the high tide zone, and 159.7 and 112.0 mg CO2 m−2 h−1 in S. alterniflora and S. mariqueter stands in the low tide zone, respectively. Aboveground NPP (ANPP), SOC, and microbial biomass were also significantly higher in the S. alterniflora stands than in the two native plant stands. S. alterniflora invasion did not significantly change soil inorganic carbon or pH. Our results indicated that enhanced ANPP by S. alterniflora exceeded invasion-induced C loss through soil respiration. This suggests that S. alterniflora invasion into the Yangtze River estuary could strengthen the net C sink of wetlands in the context of global climate change. PMID:25799512

  11. Occurrence of Cymbasoma longispinosum Bourne, 1890 in the Curuçá River estuary.

    PubMed

    Leite, Natália R; Pereira, Luci C C; Abrunhosa, Fernando; Pires, Marcus A B; Costa, Rauquírio M da

    2010-09-01

    The present work was carried out to verify the occurrence and distribution of Cymbasoma longispinosum Bourne, 1890 in a tropical Amazon estuary from North Brazil. Samplings were performed bimonthly from July/2003 to July/2004 at two different transects (Muriá and Curuçá rivers) situated along the Curuçá estuary (Pará, North Brazil). Samples were collected during neap tides via gentle (1 to 1.5 knots) 200 μm-mesh net tows from a small boat. Additional subsurface water samples were collected for the determination of environmental parameters. Males and females of Cymbasoma longispinosum were only observed during September and November/2003. The highest number of organisms was found in September/2003 at the Muriá River transect. The presence of C. longispinosum in samples obtained during September and November/2003 could probably be related to the reproductive period of this species in the studied estuary, which is directly related to the dry period in the region. The highest salinity values and the highest number of individuals observed in September/2003 corroborate with the previous assumption, since no C. longispinosum was found during the months comprising the rainy period (January to June). PMID:21562686

  12. Occurrence of Natural Contaminants of Emerging Concern in the Douro River Estuary, Portugal.

    PubMed

    Ribeiro, Ana Rita; Maia, Alexandra; Santos, Mariana; Tiritan, Maria Elizabeth; Ribeiro, Cláudia Maria Rosa

    2016-02-01

    Many studies demonstrated the presence of diverse environmental contaminants in the Douro River estuary, such as natural and synthetic estrogens, pharmaceuticals, industrial compounds and pesticides. This estuary is located between two densely populated cities and is highly impacted due to anthropogenic activities, such as industry and agriculture. Although the presence of mycotoxins and phytoestrogens, such as lignans and coumestrans, in the aquatic environment is reported by some authors, their occurrence in Portuguese waters was not investigated yet. To evaluate the presence of phytoestrogens, phytosterols and mycotoxins in Douro River estuary, water samples were collected seasonally at nine sampling points, preconcentrated by solid phase extraction and analysed by gas chromatography mass spectrometry. Local flora was collected on the riverside, in the same sampling points, for identification and evaluation of the possible relation to the presence of phytoestrogens and/or phytosterols in the estuarine water. Results showed the ubiquitous presence of mycotoxins, namely deoxynivalenol up to 373.5 ng L(-1). Both phytoestrogens and phytosterols showed a possible seasonal fluctuation, which is in accordance to the life cycle of the local flora and agricultural practices. Physicochemical parameters were also determined for water quality evaluation. This study revealed for the first time the presence of mycotoxins and lignans in estuarine waters from Portugal, and highlights the need to consider natural contaminants in future monitoring programs. PMID:26318103

  13. Mapping ecosystem services in the St. Louis River estuary (presentation)

    EPA Science Inventory

    Management of ecosystems for sustainable provision of services beneficial to human communities requires reliable data about from where in the ecosystem services flow. Our objective is to map ecosystem services in the St. Louis River with the overarching EPA goal of community sust...

  14. Mapping ecosystem services in the St. Louis River Estuary

    EPA Science Inventory

    Sustainable management of ecosystems for the perpetual flow of services beneficial to human communities requires reliable data about from where in the ecosystem services flow. Our objective is to map ecosystem services in the St. Louis River with the overarching U.S. EPA goal of ...

  15. Influence of multiple dam passage on survival of juvenile Chinook salmon in the Columbia River estuary and coastal ocean.

    PubMed

    Rechisky, Erin L; Welch, David W; Porter, Aswea D; Jacobs-Scott, Melinda C; Winchell, Paul M

    2013-04-23

    Multiple dam passage during seaward migration is thought to reduce the subsequent survival of Snake River Chinook salmon. This hypothesis developed because juvenile Chinook salmon from the Snake River, the Columbia River's largest tributary, migrate >700 km through eight hydropower dams and have lower adult return rates than downstream populations that migrate through only 3 or 4 dams. Using a large-scale telemetry array, we tested whether survival of hatchery-reared juvenile Snake River spring Chinook salmon is reduced in the estuary and coastal ocean relative to a downstream, hatchery-reared population from the Yakima River. During the initial 750-km, 1-mo-long migration through the estuary and coastal ocean, we found no evidence of differential survival; therefore, poorer adult returns of Snake River Chinook may develop far from the Columbia River. Thus, hydrosystem mitigation efforts may be ineffective if differential mortality rates develop in the North Pacific Ocean for reasons unrelated to dam passage. PMID:23576733

  16. Sediment transport and morphodynamic changes in Ziarat Estuary and Mond River Delta, the Persian Gulf

    NASA Astrophysics Data System (ADS)

    Razavi Arab, Azadeh; Haghshenas, S. Abbas; Samsami, Farzin

    2014-05-01

    The Mond River, which is considered as one of the Major Iranian rivers discharging in to the Persian Gulf, is bounded within the region from 51°10' to 54°28' E and 27°20' to 29°51' N, flowing in two provinces of Fars and Boushehr. The latest part of the river is completely meandered and the river mouth has been migrating twice during the past 50 years. Total sediment discharge of the river is estimated as 12 million cubic meter per year. Analysis of meandering river phenomenon and river mouth migration as well as evolution of the down-stream sand spits has long been one of the challenges in hydrodynamic discussions. This natural process usually takes place in rivers to provide energy equilibrium and its integration with human desires has posed as a management issue. The sediment discharging to the Persian Gulf plays an essential role in formation of Mond River Delta as well as a set of sand spits formed in downstream of the river mouth. The morpho-dynamic of entire environment of the Mond River - Mond Delta highly affects marine environment in the surrounding area. The present study offers the results of a numerical and field investigation of various features of river-delta interaction on Ziarat Estuary and the Mond Delta area. A numerical model has been utilized to investigate cases of flow and sediment transport behaviour in the coastal Mond area and future migration patterns of the River Mouth is estimated. Sediment sources and relevant contributions in morphodynamic changes of the sand spits are widely investigated through sediment constituent analysis. The results of the numerical model are compared with field observations and comprehensive GIS based analysis of historic shoreline changes from aerial photos and satellite imagery. It is concluded that the model achievements are capable to predict the observed phenomena. Management guidelines and suggestions are deducted and drawn from the calibration and verification of the results with field observations

  17. River flow and ammonium discharge determine spring phytoplankton blooms in an urbanized estuary

    NASA Astrophysics Data System (ADS)

    Dugdale, Richard; Wilkerson, Frances; Parker, Alexander E.; Marchi, Al; Taberski, Karen

    2012-12-01

    Nutrient loadings to urbanized estuaries have increased over the past decades in response to population growth and upgrading to secondary sewage treatment. Evidence from the San Francisco Estuary (SFE) indicates that increased ammonium (NH4) loads have resulted in reduced primary production, a counter-intuitive finding; the NH4 paradox. Phytoplankton uptake of nitrate (NO3), the largest pool of dissolved inorganic nitrogen, is necessary for blooms to occur in SFE. The relatively small pool of ambient NH4, by itself insufficient to support a bloom, prevents access to NO3 and bloom development. This has contributed to the current rarity of spring phytoplankton blooms in the northern SFE (Suisun Bay), in spite of high inorganic nutrient concentrations, improved water transparency and seasonally low biomass of bivalve grazers. The lack of blooms has likely contributed to deleterious bottom-up impacts on estuarine fish. This bloom suppression may also occur in other estuaries that receive large amounts of anthropogenic NH4. In 2010 two rare diatom blooms were observed in spring in Suisun Bay (followed by increased abundances of copepods and pelagic fish), and like the prior bloom observed in 2000, chlorophyll accumulated after NH4 concentrations were decreased. In 2010, low NH4 concentrations were apparently due to a combination of reduced NH4 discharge from a wastewater treatment plant and increased river flow. To understand the interactions of river flow, NH4 discharge and bloom initiation, a conceptual model was constructed with three criteria; 1) NH4 loading must not exceed the capacity of the phytoplankton to assimilate the inflow of NH4, 2) the NH4 concentration must be ≤4 μmol L-1 to enable phytoplankton NO3 uptake, 3) the dilution rate of phytoplankton biomass set by river flow must not exceed the phytoplankton growth rate to avoid "washout". These criteria were determined for Suisun Bay; with sufficient irradiance and present day discharge of 15 tons NH4-N d

  18. An assessment of natural radionuclides in water of Langat River estuary, Selangor

    NASA Astrophysics Data System (ADS)

    Hamzah, Zaini; Rosli, Tengku Nurliana Tuan Mohd; Saat, Ahmad; Wood, Ab. Khalik

    2014-02-01

    An estuary is an area that has a free connection with the open sea and it is a dynamic semi-enclosed coastal bodies. Ex-mining, aquaculture and industrial areas in Selangor are the sources of pollutants discharged into the estuary water. Radionuclides are considered as pollutants to the estuary water. Gamma radiations emitted by natural radionuclides through their decaying process may give impact to human. The radiological effect of natural radionuclides which are 226Ra, 228Ra, 40K, 238U and 232Th, were explored by determining the respective activity concentrations in filtered water along the Langat estuary, Selangor. Meanwhile, in- situ water quality parameters such as temperature, dissolve oxygen (DO), salinity, total suspended solid (TSS), pH and turbidity were measured by using YSI portable multi probes meter. The activity concentration of 226Ra, 228Ra and 40K were determined by using gamma-ray spectrometry with high-purity germanium (HPGe) detector. The activity concentrations of 226Ra, 228Ra and 40K in samples are in the range of 0.17 - 0.67 Bq/L, 0.16 - 0.97 Bq/L and 1.22 - 5.57 Bq/L respectively. On the other hand, the concentrations of uranium-238 and thorium-232 were determined by using Energy Dispersive X-ray Fluorescence Spectrometry (EDXRF). The thorium concentrations are between 0.17 ppm to 0.28 ppm and uranium concentrations were 0.25 ppm to 0.31 ppm. The results show activity concentrations of radionuclides are slightly high near the river estuary. The Radium Equivalent, Absorbed Dose Rate, External Hazard Index, and Annual Effective Dose of 226Ra, 228Ra and 40K are also studied.

  19. An assessment of natural radionuclides in water of Langat River estuary, Selangor

    SciTech Connect

    Hamzah, Zaini Rosli, Tengku Nurliana Tuan Mohd Saat, Ahmad Wood, Ab. Khalik

    2014-02-12

    An estuary is an area that has a free connection with the open sea and it is a dynamic semi-enclosed coastal bodies. Ex-mining, aquaculture and industrial areas in Selangor are the sources of pollutants discharged into the estuary water. Radionuclides are considered as pollutants to the estuary water. Gamma radiations emitted by natural radionuclides through their decaying process may give impact to human. The radiological effect of natural radionuclides which are {sup 226}Ra, {sup 228}Ra, {sup 40}K, {sup 238}U and {sup 232}Th, were explored by determining the respective activity concentrations in filtered water along the Langat estuary, Selangor. Meanwhile, in- situ water quality parameters such as temperature, dissolve oxygen (DO), salinity, total suspended solid (TSS), pH and turbidity were measured by using YSI portable multi probes meter. The activity concentration of {sup 226}Ra, {sup 228}Ra and {sup 40}K were determined by using gamma-ray spectrometry with high-purity germanium (HPGe) detector. The activity concentrations of {sup 226}Ra, {sup 228}Ra and {sup 40}K in samples are in the range of 0.17 - 0.67 Bq/L, 0.16 - 0.97 Bq/L and 1.22 - 5.57 Bq/L respectively. On the other hand, the concentrations of uranium-238 and thorium-232 were determined by using Energy Dispersive X-ray Fluorescence Spectrometry (EDXRF). The thorium concentrations are between 0.17 ppm to 0.28 ppm and uranium concentrations were 0.25 ppm to 0.31 ppm. The results show activity concentrations of radionuclides are slightly high near the river estuary. The Radium Equivalent, Absorbed Dose Rate, External Hazard Index, and Annual Effective Dose of {sup 226}Ra, {sup 228}Ra and {sup 40}K are also studied.

  20. Influence of dissolved organic matter on dissolved vanadium speciation in the Churchill River estuary (Manitoba, Canada).

    PubMed

    Shi, Yong Xiang; Mangal, Vaughn; Guéguen, Céline

    2016-07-01

    Diffusive gradients in thin films (DGT) devices were used to investigate the temporal and spatial changes in vanadium (V) speciation in the Churchill estuary system (Manitoba). Thirty-six DGT sets and 95 discrete water samples were collected at 8 river and 3 estuary sites during spring freshet and summer base flow. Dissolved V concentration in the Churchill River at summer base flow was approximately 5 times higher than those during the spring high flow (27.3 ± 18.9 nM vs 4.8 ± 3.5 nM). DGT-labile V showed an opposite trend with greater values found during the spring high flow (2.6 ± 1.8 nM vs 1.4 ± 0.3 nM). Parallel factor analysis (PARAFAC) conducted on 95 excitation-emission matrix spectra validated four humic-like (C1C4) and one protein-like (C5) fluorescent components. Significant positive relationship was found between protein-like DOM and DGT-labile V (r = 0.53, p < 0.05), indicating that protein-like DOM possibly affected the DGT-labile V concentration in Churchill River. Sediment leachates were enriched in DGT-labile V and protein-like DOM, which can be readily released when river sediment began to thaw during spring freshet. PMID:27065459

  1. Radioactive cesium dynamics derived from hydrographic observations in the Abukuma River Estuary, Japan.

    PubMed

    Kakehi, Shigeho; Kaeriyama, Hideki; Ambe, Daisuke; Ono, Tsuneo; Ito, Shin-ichi; Shimizu, Yugo; Watanabe, Tomowo

    2016-03-01

    Large quantities of radioactive materials were released into the air and the ocean as a result of the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident, caused by the 2011 Tohoku earthquake and the subsequent major tsunami off the Pacific coast. There is much concern about radioactive contamination in both the watershed of the Abukuma River, which flows through Fukushima Prefecture, and its estuary, where it discharges into the sea in Miyagi Prefecture. We investigated radioactive cesium dynamics using mixing diagrams obtained from hydrographic observations of the Abukuma River Estuary. Particulate radioactive cesium dominates the cesium load in the river, whereas the dissolved form dominates in the sea. As the salinity increased from <0.1 to 0.1-2.3, the mixing diagram showed that dissolved radioactive cesium concentrations increased, because of desorption. Desorption from suspended particles explained 36% of dissolved radioactive cesium in estuarine water. However, the dissolved and particulate radioactive cesium concentrations in the sea decreased sharply because of dilution. It is thought that more than 80% of the discharged particulate radioactive cesium was deposited off the river mouth, where the radioactive cesium concentrations in sediment were relatively high (217-2440 Bq kg(-1)). Radioactive cesium that was discharged to the sea was transported southward by currents driven by the density distribution. PMID:26698826

  2. Potential for eutrophication and nuisance algal blooms in the lower Neuse river estuary. Final report

    SciTech Connect

    Paerl, H.W.; Mallin, M.; Rudek, J.; Bates, P.W.

    1990-12-01

    Phytoplankton primary production and its environmental regulation were examined at 3 stations representative of the lower Neuse River Estuary near the Pamlico Sound interface. This study covered a 3-year period (November 1987-October 1990). The authors also examined the roles of the major phytoplankton nutrients nitrogen and phosphorus in controlling growth and bloom formation. The overall potential for nuisance blooms and associated episodes of bottom water hypoxia and anoxia was investigated in field studies. Algal biomass and production varied seasonally, with high values in summer and low values in winter. In situ nutrient addition bioassays indicated the estuary experienced a general state of N limitation with especially profound limitation during summer periods. The authors recommendations for a management strategy include reductions in Dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP), and suspended sediment loads in order to maintain the system in a nuisance bloom-free condition.

  3. Factors affecting chick provisioning by Caspian Terns nesting in the Columbia River estuary

    USGS Publications Warehouse

    Anderson, S.K.; Roby, D.D.; Lyons, Donald E.; Collis, K.

    2005-01-01

    We investigated factors affecting chick provisioning by radio-tagged Caspian Terns (Sterna caspia) nesting in a large colony on East Sand Island in the Columbia River estuary during 2001. Caspian Tern predation on juvenile salmonids (Oncorhynchus spp.) in the estuary prompted resource managers to relocate ca. 9,000 pairs of terns nesting on Rice Island (river km 34) to East Sand Island (river km 8), where terns were expected to consume fewer salmonids in favor of marine forage fishes. This study investigated factors influencing foraging success, diet composition, and overall reproductive success at the managed Caspian Tern colony. Our results indicated that daytime colony attendance by nesting terns averaged 64% and decreased throughout the chick-rearing period, while duration of foraging trips averaged 47 min and increased during the same period; these seasonal changes were more strongly related to date than chick age. Average meal delivery rates to 2-chick broods (0.88 meals h-1) were 2.6 times greater than to 1-chick broods (0.33 meals h-1). Parents delivered more juvenile salmonids to chicks during ebb tides than flood tides, but meal delivery rates to the nest remained constant, suggesting diet composition tracks relative availability of prey species. Foraging trips resulting in delivery of juvenile salmonids averaged 68% longer than foraging trips for schooling marine forage fishes, indicating higher availability of marine prey near the colony. High availability of marine forage fish in the Columbia River estuary during 2001 was apparently responsible for high colony attendance, short foraging trips, high chick meal delivery rates, and high nesting success of Caspian Terns on East Sand Island.

  4. Nutrient dynamics from the Changjiang (Yangtze River) estuary to the East China Sea

    NASA Astrophysics Data System (ADS)

    Liu, Su Mei; Qi, Xiao Hong; Li, Xiaona; Ye, Hao Ran; Wu, Ying; Ren, Jing Ling; Zhang, Jing; Xu, Wei Yi

    2016-02-01

    Water and sediment samples were collected from the Changjiang (Yangtze River) estuary and the adjacent East China Sea during impoundment of the river at the Three Gorges Dam. The concentrations of dissolved inorganic and organic nutrients, and particulate inorganic phosphorus and particulate organic phosphorus in the water column (PIP and POP, respectively) and sediments (SIP and SOP, respectively) were analyzed. The nutrient dynamics in salt marshes associated with the Changjiang estuary were also considered. In addition, river water samples were collected bimonthly in the lower reaches of the Changjiang. The concentrations of dissolved inorganic nutrients, PIP and POP showed temporal and spatial variations, which decreased from the coast to offshore areas. The dissolved organic nitrogen and phosphorus (P) concentrations showed patchy distributions, but were consistent with the distribution of phytoplankton biomass. Phosphorus is the major limiting element for phytoplankton growth. Among the various P forms, particulate P represented 38-52% of total P. The PIP and POP concentrations showed clear seasonal variations corresponding to the occurrence of the levels of suspended particulate matter. The P accumulation rates showed a decreasing trend from the coast to offshore areas, and high P burial efficiencies were found; the latter were related to a low benthic PO43 - flux and high sediment accumulation rates. The potential bioavailable P was estimated to be 65-70% of total P, of which more than two-thirds was regenerated in the water column. The salt marsh in the Changjiang estuary plays an important ecological role in nutrient transport from the river to offshore areas, and increased P limitation.

  5. Modeling the Influence of River Flow and Salt Water Intrusion in the Terengganu Estuary, Malaysia

    NASA Astrophysics Data System (ADS)

    Lee, H. L.; Tangang, F.; Hamid, M. R.; Benson, Y.; Razali, M. R.

    2016-07-01

    Salinity intrusion is a major concern when the freshwater extraction station is located in the estuary. This paper attempt to predict the salt intrusion length in the upper stretch of estuary, by applying different magnitudes of freshwater discharge at the river regime. The integrated two dimensional hydrodynamics model associated with advection dispersion model was performed to investigate the salinity intrusion. The model was well calibrated and verified by the measured data undertaken during dry season. The maximum salt intrusion length to the threshold of salinity density is 1.00 ppt on the existing condition was predicted at 9.97 km from the river mouth. Moreover, with the magnitude of 100.00 m3s-1 and 30.00 m3s-1 freshwater discharges at the upstream boundary (Kpg Tanggol), it was predicted the maximum salt intrusion length was 11.84 km and 21.41 km, respectively, from the river mouth. Therefore, it was determined the minimum freshwater discharge of approximately 100.00 m3s-1 is required at the Kpg Tanggol river gauging station, in order to maintain the acceptable salinity levels at the Pulau Musang freshwater pump house. However, the actual water discharge at the Kpg Tanggol boundary station should be higher, since the minimum discharge does not take into consideration the amount of water extraction by the Pulau Musang and SATU pump stations. Further analysis is required to execute the consequences of water extraction toward the salinity intrusion in the Terengganu estuary that coupled with projected sea level rise.

  6. Regime shifts in muddy estuaries: tidal response to river deepening and canalization

    NASA Astrophysics Data System (ADS)

    Winterwerp, J. C.; Wang, Z. B.

    2012-04-01

    Johan C. Winterwerp, Zheng Bing Wang A number of tidal rivers in Europe, amongst which the Ems River in Germany/Netherlands, and the Loire River in France are characterized by hyper-concentrated conditions with pronounced layers of fluid mud and suspended sediment concentrations exceeding 30 g/l. From an ecological point of view the sedimentary conditions in these rivers are highly problematic, as oxygen levels and primary production are very low. The present study aims at defining the conditions at which a regime shift in these rivers may occur, yielding a transition from a "normal estuary" with a classical estuarine turbidity maximum governed by estuarine circulation mainly, to hyper-concentrated conditions where sediment dynamics are mainly governed by tidal asymmetry. We hypothesize that these hyper-concentrated conditions are the result of large amplification of the tide and strong flood-dominant conditions, induced by ongoing deepening and embanking of the tidal river. Indeed, today many European rivers, amongst which the Loire and Ems, can be classified as synchronous, with an almost constant tidal amplitude along the main part of the river. Here we present the behavior of tidal asymmetry in response to deepening and embanking based on an analytical solution of the one-dimensional, linearized water movement in a converging channel, with or without intertidal area.

  7. Last century seabed morphodynamics of the Magra River estuary (Western Mediterranean Sea)

    NASA Astrophysics Data System (ADS)

    Pratellesi, Marta; Ivaldi, Roberta; Ciavola, Paolo; Sinapi, Luigi

    2016-04-01

    The estimation of morphological and volumetric changes of the delta system at the mouth of the Magra River is presented in this paper using bathymetric and sedimentological data. The data series were collected during several hydro-oceanographic surveys carried out from 1882 to 2014, processed following the hydrographic international standards and stored in the Italian Navy Hydrographic Institute database. In particular, bathymetric data characterized by the same standard and accuracy were collected using different devices such as sounding lines, single-beam and multi-beam acoustic system. This research compares Digital Terrain Models (DTMs), derived from highly accurate bathymetric data and covering different time scales (secular, half-century and decade) in order to assess and quantify the seabed morphodynamics in relation with the river sedimentary budget. The methodology and data exploitation consist mainly in the production of DTMs to study the elevation change, two-dimensional and three dimensional maps, cross-sections of the seabed, difference surfaces and computation of net volumes as well as an historical sedimentological map. These products are also an useful contribution to the aim of EU RISC-KIT Project. The results of the analysis highlight changes in the geometry of the Magra River mouth, of the coastal profile and bottom features primarily due to variations of the sedimentary budget and secondarily to wave dynamics. This behaviour is characterized by evident river mouth and coastal retreat, beach erosion and sediment bars decay and net accretion under periods of high river sediment discharge and elongate bar formation during relatively fair conditions. In the last century the main change is constituted by the disappearance of the typical constructive seabed delta morphology and the transformation into the current small estuary, with microtidal condition. This small estuary has an upper sector where river processes, sediments and bedforms dominate, a

  8. Baseline sediment trace metals investigation: Steinhatchee River estuary, Florida, Northeast Gulf of Mexico

    USGS Publications Warehouse

    Trimble, C.A.; Hoenstine, R.W.; Highley, A.B.; Donoghue, J.F.; Ragland, P.C.

    1999-01-01

    This Florida Geological Survey/U.S. Department of the Interior, Minerals Management Service Cooperative Study provides baseline data for major and trace metal concentrations in the sediments of the Steinhatchee River estuary. These data are intended to provide a benchmark for comparison with future metal concentration data measurements. The Steinhatchee River estuary is a relatively pristine bay located within the Big Bend Wildlife Management Area on the North Central Florida Gulf of Mexico coastline. The river flows 55 km through woodlands and planted pines before emptying into the Gulf at Deadman Harbor. Water quality in the estuary is excellent at present. There is minimal development within the watershed. The estuary is part of an extensive system of marshes that formed along the Florida Gulf coast during the Holocene marine transgression. Sediment accretion rate measurements range from 1.4 to 4.1 mm/yr on the basis of lead-210 measurements. Seventy-nine short cores were collected from 66 sample locations, representing four lithofacies: clay- and organic-rich sands, organic-rich sands, clean quartz sands, and oyster bioherms. Samples were analyzed for texture, total organic matter, total carbon, total nitrogen, clay mineralogy, and major and trace-metal content. Following these analyses, metal concentrations were normalized against geochemical reference elements (aluminum and iron) and against total weight percent organic matter. Metals were also normalized granulometrically against total weight percent fines (<0.062 mm). Concentrations were determined by inductively coupled plasma-atomic emission spectrometry (ICP-AES) for all metals except mercury. Mercury concentrations were determined by cold-flameless atomic absorption spectrometry (AAS). Granulometric measurements were made by sieve and pipette analyses. Organic matter was determined by two methods: weight loss upon ignition and elemental analysis (by Carlo-Erba Furnace) of carbon and nitrogen. X

  9. Acoustic propagation in the Hudson River Estuary: Analysis of experimental measurements and numerical modeling results

    NASA Astrophysics Data System (ADS)

    Radhakrishnan, Sreeram

    Underwater intrusion detection is an ongoing security concern in port and harbor areas. Of particular interest is to detect SCUBA divers, unmanned underwater vehicles and small boats from their acoustic signature. A thorough understanding of the effects of the shallow water propagating medium on acoustic signals can help develop new technologies and improve the performance of existing acoustic based surveillance systems. The Hudson River Estuary provides us with such a shallow water medium to conduct research and improve our knowledge of shallow water acoustics. Acoustic propagation in the Hudson River Estuary is highly affected by the temporal and spatial variability of salinity and temperature due to tides, freshwater inflows, winds etc. The primary goal of this research is to help develop methodologies to predict the formation of an acoustic field in the realistic environment of the lower Hudson River Estuary. Shallow water high-frequency acoustic propagation experiments were conducted in the Hudson River near Hoboken, New Jersey. Channel Impulse Response (CIR) measurements were carried out in the frequency band from 10 to 100 kHz for distances up to 200 meters in a water depth of 8-10 meters which formed the basis for experimental Transmission Loss (TL). CIR data was also utilized to demonstrate multi-path propagation in shallow water. Acoustic propagation models based on Ray Theory and Parabolic Equation methods were implemented in the frequency band from 10 to 100 kHz and TL was estimated. The sound velocity profiles required as input by acoustic propagation models were calculated from in-situ measurements of temperature, salinity and depth. Surface reflection loss was obtained from CIR data and incorporated into the acoustic propagation models. Experimentally obtained TL was used to validate the acoustic model predictions. An outcome of this research is an operational acoustic transmission loss (TL) forecast system based on the existing, Stevens New York

  10. Nutrient Inputs to Estuaries from Nine Scottish East Coast Rivers; Influence of Estuarine Processes on Inputs to the North Sea

    NASA Astrophysics Data System (ADS)

    Balls, Philip W.

    1994-10-01

    Nutrient distributions (nitrate, ammonia, phosphate and silicate) have been determined in the surface waters of nine North Sea estuaries: Tweed, Forth, Tay, Dee, Don, Ythan, Beauly/Inverness Firth, Cromarty Firth and Dornoch Firth. Seasonal variability has been examined by conducting surveys in April, July and September 1991 and February 1992. On each occasion, surveys of all nine estuaries were normally completed in 3-5 days of each other, around high water on spring tides. This intensive and strictly controlled sampling regime ensures a realistic comparison between nutrient concentrations in individual estuaries. Nutrient concentrations in individual rivers and estuaries are demonstrated to be related to land use. River catchments with intensive agriculture and low freshwater input, such as the Don and Ythan, have enhanced nitrate (up to 600 μM) and phosphate (up to 5 μM) concentrations in their estuaries. By contrast, Highland river catchments with mineral-poor soils, low populations and low agricultural intensity (Inverness, Cromarty and Dornoch Firths) generally lead to nutrient concentrations being lower in river water than in coastal seawater. Conservative mixing of dissolved nutrients is demonstrated to be a function of estuarine flushing time which controls the extent to which internal processes (biological and abiological) can modify nutrient inputs. Nutrients tend to behave conservatively in short rapidly flushed estuaries such as the Tweed, Don and Ythan. In contrast, internal processes are shown to be important when estimating riverine nutrient fluxes to the coastal zone from large slowly flushed estuaries such as the Forth, Tay and Dornoch Firth. For these systems, estimates of riverine inputs to the estuary do not provide a good estimate of the load entering the coastal zone. This is primarily due to the cycling of nutrient elements between dissolved and particulate (including sediment) phases. On a regional basis, gross nutrient inputs are

  11. Latest Holocene evolution and human disturbance of a channel segment in the Hudson River Estuary

    USGS Publications Warehouse

    Klingbeil, A.D.; Sommerfield, C.K.

    2005-01-01

    The latest Holocene sedimentary record of a cohesive channel and subtidal shoal in the lower Hudson River Estuary was examined to elucidate natural (sea-level rise, sediment transport) and anthropogenic (bulkheading, dredging) influences on the recent morphodynamic evolution of the system. To characterize the seafloor and shallow subbottom, ??? 100 km of high-resolution seismic reflection profiles (chirp) were collected within a 20-km reach of the estuary and correlated with sediment lithologies provided by eight vibracores recovered along seismic lines. Sediment geochronology with 137Cs and 14C was used to estimate intermediate and long-term sedimentation rates, respectively, and historical bathymetric data were analyzed to identify regional patterns of accretion and erosion, and to quantify changes in channel geometry and sediment volume. The shoal lithosome originated around 4 ka presumably with decelerating eustatic sea level rise during the latest Holocene. Long-term sedimentation rates on the shoal (2.3-2.6 mm/yr) are higher than in the channel (2 mm/yr) owing to hydrodynamic conditions that preferentially sequester suspended sediment on the western side of the estuary. As a result, the shoal accretes oblique to the principal axis of tidal transport, and more rapidly than the channel to produce an asymmetric cross-section. Shoal deposits consist of tidally bedded muds and are stratified by minor erosion surfaces that seismic profiles reveal to extend for 10s of meters to kilometers. The frequency and continuity of these surfaces suggest that the surficial shoal is catastrophically stripped on decadal-centennial time scales by elevated tidal flows; tidal erosion maintains the shoal at a uniform depth below sea level and prevents it from transitioning to an intertidal environment. Consequently, the long-term sedimentation rate approximates the rate of sea-level rise in the lower estuary (1-3 mm/yr). After the mid 1800s, the natural geometry of the lower Hudson

  12. The low water-leaving radiances phenomena around the Yangtze River Estuary

    NASA Astrophysics Data System (ADS)

    He, Xianqiang; Bai, Yan; Mao, Zhihua; Chen, Jianyu

    2009-09-01

    Based on the in-situ data and ocean color remote sensing data of SeaWiFS, we found there was a black water region with the normalized water-leaving radiances less than 0.5 mW/(cm2•μm•sr) at the visible light wavelength. Yangtze River Estuary locates in the East China Sea shelf with shallow water. Affected by the tide mixing and the runoff of the Yangtze River and Qiantang River, the turbidity is very high. Generally, the water-leaving radiance is high in the turbid water because of the large particle scattering. The reason of the occurrence of this black water was analyzed by the inherent optical properties and the ocean color components. The results showed that black water was caused by the relative low values of the suspended particle matter concentration and the back scattering ratio.

  13. Characteristics of CDOM Optical Properties in Two Mississippi River Influenced Estuaries

    NASA Astrophysics Data System (ADS)

    D'Sa, E. J.

    2014-12-01

    Absorption and fluorescence properties of chromophoric dissolved organic matter (CDOM) are investigated in two estuarine systems, the Barataria Basin and the Breton Sound, Louisiana, USA. These two estuarine systems located directly west and east of the Mississippi River delta have experienced significant wetland loss and have man-made freshwater diversion structures used to divert water and associated constituents from the Mississippi River into the two estuaries. In the Barataria Basin, water samples were obtained along an axial transect from the marine end member to the upper basin while in the Breton Sound, sampling was conducted along two major routes dominated by wetlands through which diverted water travels. An assessment of CDOM absorption and excitation-emission matrix (EEMs) fluorescence properties along with parallel factor analysis of the EEMs data acquired under different river discharge conditions will be presented.

  14. Salt Marsh Formation in the Lower Hudson River Estuary

    NASA Technical Reports Server (NTRS)

    Merley, Michael; Peteet, Dorothy; Hansen, James E. (Technical Monitor)

    2001-01-01

    Salt marshes are constant depositional environments and as a result contain accurate indicators of past relative sea level rise and salinity. The Hudson River marshes are at least twice as deep when compared to coastal marshes on either side of the mouth of the Hudson. The reason for this difference in sedimentation is unclear. This study uses macrofossil data as well as sediment stratigraphy in order to understand the formation and evolution of these marshes. The composition of seeds, roots, shoots and foraminifera, are used to indicate past sea levels. The four sites involved in this study are, from south to north, the Arthur Kill Marsh in Staten Island (40 36 N, 74 77W), Piermont marsh (N 4100; 73 55W) Croton Point (41 14 N; 73 50W) and Iona Island (41 18N, 73 58W). These are all tidally influenced but with increasing distances from the New York Bight, which gives a good spectrum of tidal influence. AMS-C14 dates on basal macrofossils will document the time of each marsh formation. Basal material from Arthur Kill (8 m) includes freshwater seeds such as Viola, Potomageton and Alnus along with Salix buds. Basal material from Croton Point (10 m) includes fibrous woody material, foraminifera and Zanichellia seeds and other brackish vegetational components. The basal material from Piermont (13.77 m) is lacking any identifiable macrofossils between 150 and 500 microns. The basal material from Iona Island (10 m) has vegetation such as Scirpus and Cyperus seeds, probably implying a brackish environment. The freshwater origin of the Arthur Kill marsh in Staten Island is significant because it predates either sea level rise or the western channel incision. Additional implications for this study include evidence for changes in river channel geomorphology. Reasons for the relatively deeper river marshes include possible basal clay compaction, high production due to river and marine nutrients as well as tectonic activity. This study provides the groundwork for more high

  15. The influence of estuarine conditions on the dynamics of a coastal phytoplankton community in a micro-tidal estuary: Yura River Estuary, Japan

    NASA Astrophysics Data System (ADS)

    Watanabe, K.; Fukuzaki, K.; Akiyama, S.; Ichimi, K.; Kasai, A.; Fukushima, K.; Ueno, M.; Yoshioka, T.; Yamashita, Y.

    2011-12-01

    The western side of Wakasa Bay, Tango Sea, Japan receives most of its allochthonous nutrient input from the Yura River. The Yura Estuary is classified as micro-tidal with a spring tidal range of less than 0.5 m. In summer, generally, the river discharge is low and the sea level is high, so the salt wedge extends 20 km upstream. Then, phytoplankton blooms occur due to an influx of riverine nutrients in the estuary. In contrast, during spring, river discharge is high and the salt wedge is not formed. These seasonal differences in estuarine physical and biological conditions may affect the coastal zone. The objective of this study is to examine the influence of estuarine conditions on the dynamics of the coastal phytoplankton community in this micro-tidal estuary. For this objective, field surveys were conducted both in the coastal zone and the river side of this estuary. Four sampling stations with depths of 5, 10, 20 and 30 m were set in the coastal zone, and weekly surveys were conducted from December 2009 to June 2011. Six sampling stations were set between the mouth of the Yura River and 16 km upstream, and monthly surveys were conducted in summer (from June 2010 to August 2010) and spring (from February 2011 to April 2011). Vertical profiles of salinity, water temperature and chlorophyll fluorescence were measured with a CTD profiler at each station. With water samples taken from the surface, middle, and bottom layers at each station, concentrations of chlorophyll a, pheophytin, and nutrients were analyzed. The nutrients flux from the upstream to the estuary correlated strongly with river discharge, not with nutrient concentrations. In summer, when estuarine water were stratified, marine phytoplankton (mainly diatoms) developed in the middle layer of the estuary while freshwater phytoplankton (mainly green algae) increased in the surface layer of the river mouth. Nitrate concentration in riverine water was estimated to decline 15% while the water flowed from the

  16. Freshwater inflow requirements for the protection of the critical habitat and the drinking water sources in the Yangtze River Estuary, China

    NASA Astrophysics Data System (ADS)

    Zhao, R.; Yang, Z. F.; Sun, T.; Chen, B.; Chen, G. Q.

    2009-05-01

    Freshwater inflow requirements (FIRs for short), which considered the requirements for protection of drinking water sources as well as the first-grade state protection wildlife (Acipenser sinensis) in larval periods, were analyzed in this paper for the Yangtze River Estuary, China. Based on the different levels of salinity objectives and the relationship between salinity and the freshwater inflows, the FIRs for the Yangtze River Estuary were determined. The estuary FIRs were determined based on the habitat ecosystem health from April to November with minimum and medium levels, from March to December with high level; and on the requirement of protection of drinking water sources in other months of the year, accordingly. Combined the salinity objectives of drinking water sources and critical habitat in the Yangtze River Estuary, the FIRs for the estuary are calculated to be 938.2 × 109, 729.4 × 109 and 615.5 × 109 m3 in the whole year with different levels, which is equal to 100.8%, 78.4% and 66.2% of the average annual river discharge for the Yangtze River Estuary, respectively. Annual river discharges can satisfy the medium and minimum levels of FIRs for the estuary. However, the temporal variation of the actual runoff has distinct difference from the FIRs for the estuary in critical periods (May, July and August) for the habitat ecosystem, 5% of the FIRs for the estuary should be maintained from December to February for protection of drinking water sources.

  17. Late Holocene evolution of the River Bensafrim estuary, Lagos (Portugal) - Gearchaeological remarks concerning geomorphological changings

    NASA Astrophysics Data System (ADS)

    Gomes, J. A.; Ramos-Pereira, A.; Trindade, J.

    2012-04-01

    1. The site Lagos is a city in western Algarve situated on the right margin of the Ribeira de Bensafrim. Its dissymmetric estuary has two hills: one that supports the town of Lagos and the hill of Monte Molião, known for its archaeological site. During the Late Iron Age the establishment was constrained to the top of that small hill Molião After that period, in Roman Age, people moved their location to the right river margin, founding what was then known as Laccobriga - Lagos. 2. Objectives and methodology The main objective of this study is to understand the possible causes for the abandonment of Monte Molião and what were the reasons behind the foundation of the roman city of Laccobriga? The data used were the results from the sedimentary analysis of cores in the alluvial plain of the Bensafrim valley, radiocarbon data, together with the previous excavation results and structure analysis. 3. First results: (i) In the sedimentary record, the rate sand/clay as well as several statistical parameters and shells, show different energetic environments. (ii) Radiocarbon data shows that the estuary remained open until 2800 cal BP, when a spit developed at the mouth of the estuary and a salt marsh begin to develop behind the sand barrier. (iii) Remnants of fishing activities since the Iron Age found in the archaeological site highlight different strategies for the establishment around the estuary. Archeological data tells us that, the Iron Age fishing was mainly fluvial, while later shellfish remains point that in the roman period fishing activities were made in open sea. (iv) The analyzed roman structures in the archaeological site of Monte Molião, show a clear sign of a violent seismic destruction probably related to the known 63 b.C. earthquake. 4. Conclusions (i) It is proven that in the river Bensafrim the estuary changed from an open estuary before 2800 cal BP to a closed one. This could have forced the change of the fishing habits of the populations that

  18. Sediment quality in Rivers and their estuaries of an olive oil production area, Messinia, Greece.

    NASA Astrophysics Data System (ADS)

    Anastasopoulou, Evaggelia; Pavlidou, Alexandra; Skoulikidis, Nikos; Dassenakis, Manos; Hatzianestis, Ioannis

    2014-05-01

    Sediment analysis at four major rivers (Pamisos, Aris, Velikas and Nedon) and their estuaries towards heavy metals took place in the Prefecture of Messinia, Greece, during two sampling campaigns in 2008 and 2011. The main industrial activity in the region is the operation of 250 olive oil industries and the main problem concerning pollution derives from the vast quantities of olive mill waste waters that are being generated annually most of which is currently discharged in nearby streams. Chemical parameters such as phenols, total organic carbon and certain heavy metals were found to be strongly correlated with the wastes from the olive oil industries. Major and minor elements (heavy metals) were measured in riverine and estuarine sediments. In parallel heavy metals were determined in the olive waste from a local industry, using atomic absorption spectrometry, in order to correlate the results with the sediment analysis. Major and Minor elements were recorded based upon the total percentage of the sediment samples and in order to eliminate the grain size effect, the concentrations were normalized towards Al. A pollution indice, the sediment enrichment factor, was also calculated, the high values of which towards Cr are of particular interest. Additionally organic carbon and total phenolic compounds were determined in rivers and their estuaries. High concentrations of Chromium were recorded in River Aris sediment, which seems to be the most polluted. Relatively high concentrations of zinc were encountered at rivers Aris and Pamisos while the chromium load seems to be higher near the estuaries of the rivers. The olive mill waste water analysis confirmed the existence of chromium in the waste and extremely elevated values were also found at a nearby station where these wastes tend to accumulate for decades. In contrast the results from the Nedon River indicated that it is not affected, since the low values found remained constant from the source of the river until its

  19. Estuarine research; an annotated bibliography of selected literature, with emphasis on the Hudson River estuary, New York and New Jersey

    USGS Publications Warehouse

    Embree, William N.; Wiltshire, Denise A.

    1978-01-01

    Abstracts of 177 selected publications on water movement in estuaries, particularly the Hudson River estuary, are compiled for reference in Hudson River studies. Subjects represented are the hydraulic, chemical, and physical characteristics of estuarine waters, estuarine modeling techniques, and methods of water-data collection and analysis. Summaries are presented in five categories: Hudson River estuary studies; hydrodynamic-model studies; water-quality-model studies; reports on data-collection equipment and methods; and bibliographies, literature reviews, conference proceedings, and textbooks. An author index is included. Omitted are most works published before 1965, environmental-impact statements, theses and dissertations, policy or planning reports, regional or economic reports, ocean studies, studies based on physical models, and foreign studies. (Woodard-USGS)

  20. Temporal and spatial dynamics of amphioxus population (Branchiostoma belcheri tsingtaneuse) and its influential factors in Luan River Estuary, China

    PubMed Central

    Hao, Luo; Minghui, Ma; Bin, Liang; Chenguang, Bao

    2014-01-01

    Population distribution of amphioxus (Branchiostoma belcheri tsingtauense) was investigated in the Luan River Estuary from 1999 to 2011, to describe its trends and discover the factors that influence its decline. Amphioxus are distributed on the seabed at 5–10 m depth, between the Xinkai Estuary and the Dapu River Estuary, where the primary sand components of the sediment are medium and fine, with particle size ranging from 0.001 to 1 mm. In recent years, the population density and biomass of amphioxus have sharply decreased. Changes in sediment granularity composition may significantly influence amphioxus distribution. Our data showed that the highest density region of amphioxus occurred where >90% of the sediment particles were between 0.063 and 0.5 mm in size. A reduction in sediment discharge from Luan River and the expansion of raft-breeding mariculture may be causing the decline in amphioxus through habitat destruction. PMID:25247060

  1. 18O and 226Ra in the Minjiang River estuary, China and their hydrological implications

    NASA Astrophysics Data System (ADS)

    Liu, Huatai; Guo, Zhanrong; Gao, Aiguo; Yuan, Xiaojie; Zhang, Bin

    2016-05-01

    In this work, the 2H, 18O and 226Ra values in groundwater and surface water in the Minjiang River estuary were investigated in the dry and wet seasons. The δ18O values in the dry season were always higher than those in the wet season in both groundwater and surface water because of the presence of evaporation in the water cycle process. During the dry season, the δ18O values in groundwater on the southern bank of the Minjiang River are much higher than those on the northern bank because evaporation is more intense in the farmland of the southern bank than in the urbanized northern bank. The δ18O values in the estuarine water exhibit a good positive correlation with salinity, with a coefficient of 0.96 (p = 0.05) in both seasons. The 226Ra activities in the estuarine water increase with increasing salinity because of desorption from riverine suspended particles. The 226Ra activity reaches a peak value at a salinity of 20.5. Based on a three-endmember model, the average proportions of the estuarine water are calculated to be 0.02 for groundwater, 0.39 for river water and 0.59 for seawater. From this mixing ratio, the groundwater discharge into the estuary is estimated to be 9.31 × 106 m3 d-1 in the wet season.

  2. Trace organic contamination in biota collected from the Pearl River Estuary, China: a preliminary risk assessment.

    PubMed

    Wei, S; Lau, R K F; Fung, C N; Zheng, G J; Lam, J C W; Connell, D W; Fang, Z; Richardson, B J; Lam, P K S

    2006-12-01

    The marine ecosystem of the Pearl River Delta, located on the southern coast of China, has been heavily exploited following the rapid economic growth that has occurred since the 1980s. This investigation aimed to elucidate trace organic contamination in marine biota inhabiting the Pearl River Delta area. Biota samples, including green-lipped mussels (Perna viridis), oysters (Crassostrea rivularis) and shrimp (Penaeus orientalis) were sampled from 16 stations fringing the Estuary. Elevated concentrations (on a dry weight basis) of polycyclic aromatic hydrocarbons (27.8-1041.0 ng/g), petroleum hydrocarbons (1.7-2345.4 microg/g), polychlorinated biphenyls (2.1-108.8 ng/g), DDTs (1.9-79.0 ng/g), and hexachlorocyclohexanes (n.d.-38.4 ng/g) were recorded. A human health risk assessment was conducted to estimate the risk to local residents associated with the consumption of biota collected from the Pearl River Estuary. The results indicated that PCBs were at levels that may cause deleterious health effects in populations that consume large amounts of seafood. However, it would be instructive to establish health criteria for trace organic contaminants that are specific to the local populations, in order to derive a more accurate and relevant health risk assessment. PMID:16908034

  3. Deforestation monitoring in the Amazon River estuary by multi-temporal Envisat ScanSAR data

    NASA Astrophysics Data System (ADS)

    Chen, F.; Ishwaran, N.; Brito Pezzuti, J. C.

    2016-04-01

    In this study, we have capitalized on the all-weather, all-day operational capability of spaceborne synthetic aperture radar (SAR) systems and used multi-temporal (from 2002 to 2006), multi-track (track 174, 360 and 447) Envisat ScanSAR amplitude images for deforestation mapping and change detection in the Amazon River estuary. A synergistic approach to deforestation mapping was adopted using SAR backscattering anomalies, the neighbouring forest constraint and DEM-derived slopes based on the three following characteristics: (1) backscattering is reduced in regions suspected to have undergone deforestation; (2) open regions without neighbouring forests were identified for removal; and (3) false-alarms linked to water bodies are mitigated using the shape threshold of flat-slope objects. Our results show that deforestation in the Amazon River estuary continues to be a serious problem, particularly along the rivers, streams or roads, which are more susceptible to anthropogenic activities than other areas. Up to 2006, the deforested portion accounts for 4.6 per cent (3,096,000 pixels) of the entire study site of approximately 458,000 square kilometers (67,320,000 pixels). However, this figure, validated by Landsat ETM images, may have overestimated deforestation to some extent. Nevertheless, multi-temporal analysis using SAR systems, as done in this study, have a clear potential for surveillance of deforestation in the Amazon, particularly in light of the frequent cloud cover typical of the area and the limitations of deforestation monitoring by means of optical satellite imagery.

  4. 210Pb chronology and trace metal geochemistry in the intertidal sediment of Qinjiang River estuary, China

    NASA Astrophysics Data System (ADS)

    Xia, Peng; Meng, Xianwei; Feng, Aiping; Yin, Ping; Wang, Xiangqin; Zhang, Jun

    2012-06-01

    Historical records of metal inputs were studied by using a sediment core collected from a sand-rich mudflat in the Qinjiang River estuary, China. 210Pb chronology was used to reconstruct the fluxes of Hg, Cu, Pb, Zn, Cd, Cr and As to the core site during the last 86 years. Based on the constant initial concentration model, the sedimentation rates are 1.18 cm year-1 in the top 30 cm sandy layer and 0.92 cm year-1 in the muddy bottom layer. To compensate for grain-size and mineralogy effects on metal concentrations, aluminum was used as the normalizing element. The enrichment factors ( EF) indicate that the natural inputs had prevailed up to the early 1980s. After this period, the intensity of human activities has resulted in continual increasing trend of metals towards the surface. Recent sediment samples from the Qinjiang River estuary are found moderately enriched by Cd ( EF>1.5) and slightly enriched by other metals ( EF<1.5). Considering that the drainage area of the Qinjiang River is mostly agricultural land, the increased Cd may be due to the usage of fertilizers and pesticides in agricultural activities and the combustion of fossil fuels.

  5. Foraging ecology of Caspian Terns in the Columbia River Estuary, USA

    USGS Publications Warehouse

    Lyons, Donald E.; Roby, D.D.; Collis, K.

    2005-01-01

    Comparisons were made of the foraging ecology of Caspian Terns (Sterna caspia) nesting on two islands in the Columbia River estuary using radio telemetry and observations of prey fed to chicks and mates at each colony. Early in the chick-rearing period, radio-tagged terns nesting at Rice Island (river km 34) foraged mostly in the freshwater zone of the estuary close to the colony, while terns nesting on East Sand Island (river km 8) foraged in the marine or estuarine mixing zones close to that colony. Late in the chick-rearing period, Rice Island terns moved more of their foraging to the two zones lower in the estuary, while East Sand Island terns continued to forage in these areas. Tern diets at each colony corresponded to the primary foraging zone (freshwater vs. marine/ mixing) of radio-tagged individuals: Early in chick-rearing, Rice Island terns relied heavily on juvenile salmonids (Oncorhynchus spp., 71% of identified prey), but this declined late in chick-rearing (46%). East Sand Island terns relied less on salmonids (42% and 16%, early and late in chick-rearing), and instead utilized marine fishes such as Anchovy (Engraulis mordax) and Herring (Clupea pallasi). Throughout chick-rearing, Rice Island terns foraged farther from their colony (median distance: 12.3 km during early chick-rearing and 16.9 km during late chick-rearing) than did East Sand Island terns (9.6 and 7.7 km, respectively). The study leads to the conclusion that Caspian Terns are generalist foragers and make use of the most proximate available forage fish resources when raising young.

  6. The spatial-temporal distribution of particulate organic carbon in the Pearl River Estuary

    NASA Astrophysics Data System (ADS)

    Liu, Dong; Zhu, Qiankun; Chen, Jianyu; Gong, Fang; Wei, Ji-An

    2015-10-01

    Particulate Organic Carbon (POC) plays an important role in sink of atmospheric CO2, global carbon cycle, etc. Around river estuary, POC is sourced from terrestrial ecosystem and aquatic ecosystem; its distribution features might be complex and likely to change with time. Based on in-situ samples from four seasonal cruises, we discussed spatial-temporal distribution and remote sensing monitoring of POC concentration in the Pearl River Estuary (PRE). Being affected by larger discharge from the Pearl River, surface POC concentrations in summer were usually higher than those in other three seasons, similar, in the PRE. However, because of sediment resuspension, POC concentrations at the bottom layer were higher than those at the surface layer. Taking the PRE as an example, remote sensing monitoring of POC concentration in case II water around estuary was also discussed. On the one hand, on the basis of Chlorophyll-a (Chl-a) and Total Suspended Matter (TSM) concentrations inversed by published algorithms, we can estimate surface POC concentration through multiple linear regression equation: POC=0.042*Chl-a+0.014*TSM+0.1595, R=0.9156. On the other hand, great relationships between surface POC concentrations and total particle absorption coefficient at 667nm (TPabs(667)) and 678nm (TPabs(678)) were also found: POC=3.813*TPabs(667)+0.0684, R=0.8769 and POC=3.9175*TPabs(678)+0.0624, R=0.8745. They implied the possibility of estuarine POC monitoring from space through remote sensing reflectance at 667nm or 678nm.

  7. [Preliminary results concerning summer-time denitrification in the Jiulong River Estuary].

    PubMed

    Chen, Neng-Wang; Wu, Jie-Zhong; Hong, Hua-Sheng

    2011-11-01

    Denitrification is an important process mitigating nitrogen (N) pollution in aquatic systems. Water samples in 13 sites throughout the Jiulong River Estuary were collected in July, 2010 in a preliminary investigation of the denitrification rate in this area. As end-products of denitrification, dissolved N2 was measured by determining N2 : Ar ratios using MIMS (HPR-40), while the concentration of nitrous oxide (N2O) dissolved in water was determined by Purge and Trap-Gas Chromatography. The results showed significant spatial variance of net increase of dissolved N2 (ranging between - 9.9 and 66.8 micromol x L(-1)) and N2O (ranging between 4.3 and 31.5 nmol x L(-1)) in the Jiulong River Estuary. The net increase of dissolved N2 and N2O declined gradually from river sites to sea sites. Dissolved N2O was supersaturated by 170%-562%. The air-water fluxes of N2 ranged between -2.9 and 53.2 mmol x (m2 x d) (-1), and N2O between 5.2 and 23.9 micromol x (m2 x d)(-1). The N2O yield shared only 0.03% - 1.2% (average 0.25%) of total N air-water flux. The results suggested that water temperature and nutrient (N and P) were the key factors influencing denitrification. The denitrification rate is controlled by nitrate level at fresh-water sites with salinity < 0.5%. However, in salty waters, net increase in N2 and N2O mainly originated from denitrification occurring upstream of the estuary, and was dominated by the salinity gradient due to tidal mixing. PMID:22295617

  8. Assessing benthic ecological status in coastal area near Changjiang River estuary using AMBI and M-AMBI

    NASA Astrophysics Data System (ADS)

    Liu, Lusan; Li, Baoquan; Lin, Kuixuan; Cai, Wenqian; Wang, Quanchao

    2014-03-01

    The Changjiang (Yangtze) River estuary has been subject to a variety of anthropogenic pressures in recent decades. To assess the ecological health of the coastal benthic ecosystem adjacent to the estuary, three surveys were conducted in 2005, 2009, and 2010. The AZTI's Marine Biotic Index (AMBI) and multivariate-AMBI (M-AMBI) were used to analyse the benthic ecological status of this coast. The AMBI indicate that the ecological status of the coast adjacent to the Changjiang River estuary was only slightly degraded in all 3 years. In contrast, the M-AMBI indicated that the ecological status was seriously degraded, a result that is most likely due to pollution and eutrophication induced by human activities. The assessment of the coast's ecological status by the AMBI was not in agreement with that of the M-AMBI at some stations because of lower biodiversity values at those sites. The analysis of the two indices integrated with abiotic parameters showed that the M-AMBI could be used as a suitable bio-indicator index to assess the benthic ecological status of the coast adjacent to the Changjiang River estuary. The reference conditions proposed for the coast of the Changjiang River estuary should be further evaluated in future studies. Designation of local species could also provide an important reference for Chinese waters. To improve the reliability of AMBI and M-AMBI, further research into the ecology of local species is required to understand their arrangement in ecological groups.

  9. Roberts Bank: Ecological crucible of the Fraser River estuary

    NASA Astrophysics Data System (ADS)

    Sutherland, Terri F.; Elner, Robert W.; O'Neill, Jennifer D.

    2013-08-01

    Roberts Bank, part of the Fraser River delta system on Canada's Pacific coast, is a dynamic estuarine environment supporting important fisheries as well as internationally significant populations of migratory shorebirds. The 8000 ha bank environment comprises a complex of riparian boundaries, intertidal marshes, mud and sand flats, eelgrass meadows, macroalgae and biofilms. Anthropogenic developments (a ferry causeway in 1961 and a port causeway in 1969) have been responsible for changes in tidal flow patterns, tidal elevation, sediment transport and the net expansion of eelgrass beds. The goals of the present study were to (1) directly compare geotechnical properties spanning each side of the coalport causeway, and (2) enhance our understanding of the intercauseway ecosystem under a high-resolution sampling design. Sediment properties (grain size, porosity, organic content, and chlorophyll) and biological communities (eelgrass, macrofauna (0.5-1.0 mm) and meiofauna (0.063-0.5 mm)) were surveyed in 1997 at three stations outside the intercauseway area and three lateral transects spanning the intercauseway tidal flat at tidal heights representing three different habitats: biofilm, Zostera japonica, and Zostera marina. A fine-silt organic-rich porous deposit was observed on the shoreward north side of the coalport causeway relative to the south counterpart, suggesting that consolidation and erosion processes could likely not keep pace with the deposition of Fraser River silt. High chlorophyll levels were found in the protected shoreward northern border of the ferry causeway where fine sands dominate and higher water transparency exists, owing to the redirection of the silt-laden river plume by the coalport causeway. Principle Components Analysis revealed a positive relationship between these porous, organic-rich sediments and cumacean abundance in all regions where eelgrass was absent, including the north side of the coalport causeway. Further, a positive

  10. An improved algorithm for retrieving chlorophyll-a from the Yellow River Estuary using MODIS imagery.

    PubMed

    Chen, Jun; Quan, Wenting

    2013-03-01

    In this study, an improved Moderate-Resolution Imaging Spectroradiometer (MODIS) ocean chlorophyll-a (chla) 3 model (IOC3M) algorithm was developed as a substitute for the MODIS global chla concentration estimation algorithm, OC3M, to estimate chla concentrations in waters with high suspended sediment concentrations, such as the Yellow River Estuary, China. The IOC3M algorithm uses [Formula: see text] to substitute for switching the two-band ratio of max [R (rs) (443 nm), R (rs) (488 nm)]/R (rs) (551 nm) of the OC3M algorithm. In the IOC3M algorithm, the absorption coefficient of chla can be isolated as long as reasonable bands are selected. The performance of IOC3M and OC3M was calibrated and validated using a bio-optical data set composed of spectral upwelling radiance measurements and chla concentrations collected during three independent cruises in the Yellow River Estuary in September of 2009. It was found that the optimal bands of the IOC3M algorithm were λ(1) = 443 nm, λ(2) = 748 nm, λ(3) = 551 nm, and λ(4) = 870 nm. By comparison, the IOC3M algorithm produces superior performance to the OC3M algorithm. Using the IOC3M algorithm in estimating chla concentrations from the Yellow River Estuary decreases 1.03 mg/m(3) uncertainty from the OC3M algorithm. Additionally, the chla concentration estimated from MODIS data reveals that more than 90 % of the water in the Yellow River Estuary has a chla concentration lower than 5.0 mg/m(3). The averaged chla concentration is close to the in situ measurements. Although the case study presented herein is unique, the modeling procedures employed by the IOC3M algorithm can be useful in remote sensing to estimate the chla concentrations of similar aquatic environments. PMID:22707149

  11. Phytoplankton Abundance and Generic Composition Data for the Potomac River and Estuary, Maryland

    USGS Publications Warehouse

    Cohen, R.R.H.; Pollock, S.O.; Stoelzel, V.E.; Boulukos, K.E.

    1985-01-01

    Phytoplankton of the Potomac River and Estuary were counted and identified to the generic level. Double-blind precision tests for an individual counter yielded a standard deviation that was * 10 percent of the mean. Differences between three counters exceeded * 10 percent, and a curve could be fit to calibration counts to yield correlation coefficients of 0.70 to 0.86 between counters. Counters identified the same genera that comprised the highest and second highest percentages of the population in 88 percent of the calibration samples.

  12. Sediment concentrations and loads in the Loxahatchee River estuary, Florida, 1980-82

    USGS Publications Warehouse

    Sonntag, Wayne H.; McPherson, Benjamin F.

    1984-01-01

    This study was conducted to estimate the magnitude of sediment loads and the general spatial and temporal patterns of sediment transport in the Loxahatchee River estuary, Florida. Mean concentrations of suspended sediment generally were higher in the Jupiter Inlet area than in the remainder of the embayment area. Concentrations of suspended sediment varied with season and weather conditions. Concentrations in selected tributaries following Tropical Storm Dennis in August 1981 immediately increased as much as 16 times over concentrations before the storm. Suspended-sediment loads from the tributaries were also highly seasonal and storm related. During a 61-day period of above-average rainfall that included Tropical Storm Dennis, 5 major tributaries discharged 926 tons (short) of suspended sediment to the estuary, accounting for 74 percent of the input for the 1981 water year and 49 percent of the input for the 20-month study period. Suspended-sediment loads at Jupiter Inlet and at the mouth of the estuary embayment on both incoming and outgoing tides far exceeded tributary loads, but the direction of long-term, net tidal transport was not determined. (USGS)

  13. Evaluation of distribution and sources of sewage molecular marker (LABs) in selected rivers and estuaries of Peninsular Malaysia.

    PubMed

    Magam, Sami M; Zakaria, Mohamad Pauzi; Halimoon, Normala; Aris, Ahmad Zaharin; Kannan, Narayanan; Masood, Najat; Mustafa, Shuhaimi; Alkhadher, Sadeq; Keshavarzifard, Mehrzad; Vaezzadeh, Vahab; Sani, Muhamad S A; Latif, Mohd Talib

    2016-03-01

    This is the first extensive report on linear alkylbenzenes (LABs) as sewage molecular markers in surface sediments collected from the Perlis, Kedah, Merbok, Prai, and Perak Rivers and Estuaries in the west of Peninsular Malaysia. Sediment samples were extracted, fractionated, and analyzed using gas chromatography mass spectrometry (GC-MS). The concentrations of total LABs ranged from 68 to 154 (Perlis River), 103 to 314 (Kedah River), 242 to 1062 (Merbok River), 1985 to 2910 (Prai River), and 217 to 329 ng g(-1) (Perak River) dry weight (dw). The highest levels of LABs were found at PI3 (Prai Estuary) due to the rapid industrialization and population growth in this region, while the lowest concentrations of LABs were found at PS1 (upstream of Perlis River). The LABs ratio of internal to external isomers (I/E) in this study ranged from 0.56 at KH1 (upstream of Kedah River) to 1.35 at MK3 (Merbok Estuary) indicating that the rivers receive raw sewage and primary treatment effluents in the study area. In general, the results of this paper highlighted the necessity of continuation of water treatment system improvement in Malaysia. PMID:26581689

  14. Impact of river basin management on coastal water quality and ecosystem services: A southern Baltic estuary

    NASA Astrophysics Data System (ADS)

    Schernewski, Gerald; Hürdler, Jens; Neumann, Thomas; Stybel, Nardine; Venohr, Markus

    2010-05-01

    Eutrophication management is still a major challenge in the Baltic Sea region. Estuaries or coastal waters linked to large rivers cannot be managed independently. Nutrient loads into these coastal ecosystems depend on processes, utilisation, structure and management in the river basin. In practise this means that we need a large scale approach and integrated models and tools to analyse, assess and evaluate the effects of nutrient loads on coastal water quality as well as the efficiency of river basin management measures on surface waters and especially lagoons and estuaries. The Odra river basin, the Szczecin Lagoon and its coastal waters cover an area of about 150,000 km² and are an eutrophication hot-spot in the Baltic region. To be able to carry out large scale, spatially integrative analyses, we linked the river basin nutrient flux model MONERIS to the coastal 3D-hydrodynamic and ecosystem model ERGOM. Objectives were a) to analyse the eutrophication history in the river basin and the resulting functional changes in the coastal waters between early 1960's and today and b) to analyse the effects of an optimal nitrogen and phosphorus management scenario in the Oder/Odra river basin on coastal water quality. The models show that an optimal river basin management with reduced nutrient loads (e.g. N-load reduction of 35 %) would have positive effects on coastal water quality and algae biomass. The availability of nutrients, N/P ratios and processes like denitrification and nitrogen-fixation would show spatial and temporal changes. It would have positive consequences for ecosystems functions, like the nutrient retention capacity, as well. However, this optimal scenario is by far not sufficient to ensure a good coastal water quality according to the European Water Framework Directive. A "good" water quality in the river will not be sufficient to ensure a "good" water quality in the coastal waters. Further, nitrogen load reductions bear the risk of increased

  15. PPCPs in Jiulong River estuary (China): Spatiotemporal distributions, fate, and their use as chemical markers of wastewater.

    PubMed

    Sun, Qian; Li, Yan; Li, Mingyue; Ashfaq, Muhammad; Lv, Min; Wang, Hongjie; Hu, Anyi; Yu, Chang-Ping

    2016-05-01

    The occurrence and fate of 50 pharmaceuticals and personal care products (PPCPs) were investigated in the surface water of Jiulong River estuary in the southeast of China in spring, wet season, summer, autumn and winter. Results demonstrated a wide distribution of PPCPs in Jiulong River estuary, where 34 PPCPs were detected at least once and 5 PPCPs were detected in all the samples, including caffeine, diclofenac, metoprolol, methyl paraben, and propyl paraben. Spatial and seasonal variations were observed. Special emphasis was placed on the PPCP fate in the estuary. Most PPCPs showed a non-conservative behavior in the estuary, while the non-steroidal anti-inflammatory drugs and bisphenol A showed a pseudo-conservative behavior. The non-conservative and pseudo-conservative behavior was attributed to the combination of the seawater dilution, the introduction of PPCPs via the sewage water, and the physical, chemical, or biological removal processes. Furthermore, PPCP concentrations showed drastic variations in the turbidity maximum zones. To our best knowledge, this is the first work to indicate the pseudo-conservative behavior of PPCPs in the estuary, and to show the drastic variations of PPCPs in the turbidity maximum zone. In addition, the ratio of labile to conservative PPCPs was calculated to track the source of untreated sewage contamination. Results showed a significantly higher ratio compared to the average value in WWTP effluents, indicating the ubiquitous discharge of untreated domestic wastewater in Jiulong River estuary. In addition, the high ratio of bisphenol A to conservative PPCPs implied the potential input of untreated industrial wastewater in Jiulong River estuary. PMID:26899854

  16. Morphodynamics, stratigraphy, and sediment transport patterns of the Kennebec River estuary, Maine, USA

    NASA Astrophysics Data System (ADS)

    Fenster, M. S.; FitzGerald, D. M.

    1996-12-01

    Sediment transport and circulation patterns within the lower Kennebec River estuary, Maine (˜20 km) have been investigated over a two year and nine month period using fathometer profiles and side-scan sonograms in conjunction with flow measurements, fresh-water discharge data, and grain-size data. The geologic history of the estuary is inferred from high-resolution seismic profiles and bridge borings. Subbottom data corroborate a five-stage evolutionary history that has been determined for other areas of the west-central Maine coast. Scattered deposits of glacial till (diamict) and stratified drift overly a Precambrian to Paleozoic metasedimentary bedrock basement. The glacio-marine blue clay of the Presumpscot Formation unconformably overlies the diamict and drift and drapes the basement, where till is absent. The clay surface is an erosional unconformity formed during the last sea-level lowstand. During subsequent sea-level rise, a relatively coarse-grained estuarine fill was deposited within a flood-dominated, relatively large paleo-Kennebec River estuary. As the rates of sea-level rise slowed, the system shifted to an ebb-dominated estuary in which the estuarine fill underwent reworking and downstream net transport. Bathymetric data show a hierarchical arrangement of bedforms ranging in size and morphology from well-developed, ebb-oriented transverse bars to superimposed simple, straight-crested megaripples. The transverse bars were stable over the study period. The reworking and migration of the smaller forms are closely linked to seasonal variations in the relative contributions between tidal flow and fresh-water discharge. During the spring, large-magnitude discharge events augment ebb-tidal flows. The ebb-reinforced flows dominate the system and result in a net downstream transport of medium- to coarse-grained sand. Estuarine stratification plays an important role in sediment transport during non-spring months. From mid-summer to fall, salinity gradients

  17. A semi-analytical total suspended sediment retrieval model in turbid coastal waters: a case study in Changjiang River Estuary.

    PubMed

    Chen, Jun; D'Sa, Eurico; Cui, Tingwei; Zhang, Xunhua

    2013-06-01

    A simple semi-analytical model to estimate total suspended sediment matter (3S) was established for estimating TSM concentrations in Changjiang River Estuary. The results indicate that 3S model with near-infrared wavelengths provide good estimates of TSM concentrations in the study region. Furthermore, the applicability of 3S model was evaluated using an independent data set taken from Oujiang river estuary during September 2012. The results indicate that providing an available atmospheric correction scheme for satellite imagery, the 3S model could be used for quantitative monitoring of TSM concentration in coastal waters, even though local bio-optical information is still needed to reinitialize the model. PMID:23736555

  18. The tidal exchange of Callianassa californiensis (Crustacea, Decapoda) larvae between the ocean and the Salmon River estuary, Oregon

    NASA Astrophysics Data System (ADS)

    Johnson, Gary E.; Gonor, J. J.

    1982-05-01

    This study estimated the net flux of larvae of the anomuran crustacean Callianassa californiensis between the ocean and the Salmon River Estuary, Oregon (45°N, 124°W). Measurements of tidal current velocity, temperature and salinity were made concurrently with plankton sampling through eight weekly daylight tidal cycles. Zoea I larvae released in the estuary are flushed into the ocean on ebb tides before further development. Zoea I density and tidal discharge are highest early in the ebb. The ebb flux is greater than the flood flux of larvae from the ocean, resulting in a net flux out of the estuary. No retention of larvae in the estuary was found. Megalopae entered the estuary on flood tides in August and did not leave on the following ebb tides. These recruits to the benthic population spent most of the larval period in the nearshore oceanic plankton during the upwelling season. The Salmon River estuary hydrography is typical for Pacific north-west estuarine embayments. Tidal flushing of larvae into the ocean, development in coastal waters and exchange between embayments is probably common for lower estuarine benthic species with planktonic larvae.

  19. A sampler for coring sediments in rivers and estuaries

    USGS Publications Warehouse

    Prych, Edmund A.; Hubbell, D.W.

    1966-01-01

    A portable sampler developed to core submerged unconsolidated sediments collects cores that are 180 cm long and 4.75cm in diameter. The sampler is used from a 12-m boat in water depths up to 20 m and in flow velocities up to 1.5m per second to sample river and estuarine deposits ranging from silty clay to medium sand. Even in sand that cannot be penetrated with conventional corers, the sampler achieves easy penetration through the combined application of vibration, suction, and axial force. A piston in the core barrel creates suction, and the suspension system is arranged so that tension on the support cable produces both a downward force on the core barrel and a lateral support against overturning. Samples are usually retained because of slight compaction in the driving head; as a precaution, however, the bottom of the core barrel is covered by a plate that closes after the barrel is withdrawn from the bed. Tests show that sample-retainers placed within the driving head restrict penetration and limit core lengths. Stratification within cores is disrupted little as a result of the sampling process.

  20. Impact of entrainment and impingement on fish populations in the Hudson River estuary. Volume I. Entrainment-impact estimates for six fish populations inhabiting the Hudson River estuary

    SciTech Connect

    Boreman, J.; Barnthouse, L.W.; Vaughn, D.S.; Goodyear, C.P.; Christensen, S.W.; Kumar, K.D.; Kirk, B.L.; Van Winkle, W.

    1982-01-01

    This volume is concerned with the estimation of the direct (or annual) entrainment impact of power plants on populations of striped bass, white perch, Alosa spp. (blueback herring and alewife), American shad, Atlantic tomcod, and bay anchovy in the Hudson River estuary. Entrainment impact results from the killing of fish eggs, larvae, and young juveniles that are contained in the cooling water cycled through a power plant. An Empirical Transport Model (ETM) is presented as the means of estimating a conditional entrainment mortality rate (defined as the fraction of a year class which would be killed due to entrainment in the absence of any other source of mortality). Most of this volume is concerned with the estimation of several parameters required by the ETM: physical input parameters (e.g., power-plant withdrawal flow rates); the longitudinal distribution of ichthyoplankton in time and space; the duration of susceptibility of the vulnerable organisms; the W-factors, which express the ratios of densities of organisms in power plant intakes to densities of organisms in the river; and the entrainment mortality factors (f-factors), which express the probability that an organism will be killed if it is entrained. Once these values are obtained, the ETM is used to estimate entrainment impact for both historical and projected conditions.

  1. Hydrochemical and isotopic characteristics of estuarial seawater and river water of Bailanghe in Laizhou Bay, China

    NASA Astrophysics Data System (ADS)

    Yang, Qiaofeng; Xu, Suning; Wang, Ruijiu; Li, Wenpeng; Wang, Zhiyi; Mei, Junjun; Ding, Zhilei; Yang, Peijie; Yu, Liangju; Lv, Tieying; Bai, Gang; Kang, Wei

    2016-04-01

    In the study of seawater intrusion, seawater is usually taken as an end-member that mixes with other source(s). However, compared to standard seawater, the coastal seawater particularly that near the estuary, can be strongly influenced by the rivers into the sea and by coastal human activities. Their composition can be thus continuously changed and redistributed with space and time. Therefore, before investigating seawater intrusion in a certain area, it is essentially important to determine the features of the estuarine seawater (e.g. the mixture percentage between standard seawater and river water). In this study, we aimed to gain a clear situation of the seawater intrusion in Laizhou Bay, Southern Bohai, China. The issue aforementioned was investigated by comparing the stable isotopic and hydrochemical composition of the marine and river water collected in this area. Samples investigated include 5 surface water samples collected at the downstream of the Bailanghe and 7 seawater samples near the estuary of Laizhou Bay. Inert tracers (δD, δ18O, Cl, Br) and reaction tracers (Na, Mg, SO4, HCO3, Ca, NO3) are particularly analyzed. The major results are as follows: 1) All the river water samples fall below the Global Meteoric Water Line in the δD - δ18O diagram, reflecting evaporation of the upstream reservoir water. The seawater samples fall on the mixing line of standard seawater and the river water in the stable isotopic diagram. 2) The Cl-δ18O diagram indicates widespread dissolution of evaporate into the river, while high concentration of Ca and HCO3‑, as well as the SO42‑ - Cl relation of the river water samples reflect the dissolution of CO2 , carbonate and sulfate in the atmosphere and on the ground. 3) The Br/Cl ratios of seawater samples are closed to the marine ratios. This together with the plots of major ions vs. Cl suggest that the seawater samples are originated from the mixture of standard seawater and river water. Therefore, when referring to

  2. Historical eutrophication in a river-estuary complex in mid-coast Maine.

    PubMed

    Köster, Dörte; Lichter, John; Lea, Peter D; Nurse, Andrea

    2007-04-01

    European settlement of New England brought about a novel disturbance regime that impacted rivers and estuaries through overfishing, deforestation, dams, and water pollution. The negative consequences of these activities intensified with industrialization in the 19th and 20th centuries, often resulting in ecosystem degradation. Since environmental legislation was implemented in the 1970s, improvement in water quality has been tangible and widespread; however, ecological recovery can require substantial amounts of time and may never be complete. To document the natural baseline conditions and investigate the recovery of a severely degraded river-estuary complex in mid-coast Maine, we examined diatoms, pollen, total organic carbon, total nitrogen, stable isotopes, total phosphorus, biogenic silica, and trace metals in intertidal sediments and established a chronology with 14C, 210Pb, and indicator pollen horizons. Both climate variability and human effects were evident in the sedimentary record of Merrymeeting Bay, the freshwater tidal portion of the Kennebec estuary. Natural climate variability was apparent in an episode of high sedimentation and altered diatom abundance during the 12th and 13th centuries and in changing pollen abundances between the 16th and 19th centuries, indicative of regional cooling. During the 18th century, colonial land clearance began an era of high sedimentation and eutrophication that strongly intensified with industrialization during the late 19th and 20th centuries. Improvements in water quality over the past 30 years in response to environmental regulation had little effect on ecosystem recovery as represented by the sedimentary record. Diatom composition and productivity and high fluxes of organic C, total P, and biogenic Si in recent sediments indicate that rates of nutrient loading remain high. These environmental proxies imply that aquatic productivity in Merrymeeting Bay was originally nutrient limited and water clarity high

  3. River flow control on intertidal mudflat sedimentation in the mouth of a macrotidal estuary

    NASA Astrophysics Data System (ADS)

    Cuvilliez, Antoine; Lafite, Robert; Deloffre, Julien; Lemoine, Maxence; Langlois, Estelle; Sakho, Issa

    2015-06-01

    The objective of this study is to analyze the impact of hydrological variability influenced by climatic phenomena upon the sedimentary exchange between the turbidity maximum (TM) and a river mouth intertidal mudflat. This study, carried out over a period of 10 years (1997-2006) in the Seine Estuary (France), is specifically focused on two extreme periods: a wet one from 2001 to 2002 and a drier one from 2005 to 2006. This study is based on an original approach combining data gathered via low-altitude remote sensing with altimeter readings and ground-level measurements. During this 10 year period, we observed a link between climate change and the sedimentary processes on the mudflat surface. The modifications of sedimentary processes are mainly connected to the multiannual variability of hydrological flow rates that control the positioning of the turbidity maximum, the source of the sedimentary material deposited in this intertidal zone. The TM at the mouth of the Seine estuary is well developed; its maximum mass is estimated to be between 300,000 tons and 500,000 tons (Avoine et al., 1981) with maximum concentrations in the surface waters ranging from 1 to 2 g • l- 1 (Le Hir et al., 2001). Most of the fine particles stored within the TM have been found to originate from within the catchment area (Dupont et al., 1994). In the Seine estuary, the dynamics of the estuarine TM, in response to hydrodynamic forcings, have been previously described (Avoine et al., 1981) and modeled (e.g. Brenon and Le Hir, 1999; Le Hir et al., 2001). The TM is upstream of the northern mudflat when the river flow is low (< 450 m • s- 1) and nearby the study area when the river flow is higher. Thus during wet periods, the sedimentation rates increase by + 17 cm • y- 1, while during the drier one (when the turbidity maximum is located upstream of the estuary) we observed an erosion rate of 7.6 cm • y- 1. Sedimentation events in the mudflat resulting from spring tides are less frequent

  4. An Ecosystem-Based Restoration Plan with Emphasis on Salmonid Habitats in the Lower Columbia River and Estuary

    SciTech Connect

    Johnson, Gary E.; Thom, Ronald M.; Whiting, Allan H.; Sutherland, George B.; Berquam, Taunja J.; Ebberts, Blaine; Ricci, Nicole M.; Southard, John A.; Wilcox, Jessica D.

    2003-10-14

    The Bonneville Power Administration (BPA), in coordination with the U. S. Army Corps of Engineers (COE) and NOAA Fisheries, originated this project (BPA Project No. 2002-076; Contract No. DE-AC06-76RL01830, Release No. 652-24). Their intent was to develop a useful habitat restoration plan for the lower Columbia River and estuary to help guide restoration efforts and fulfill Reasonable and Prudent Alternative Action 159 of the 2000 National Marine Fisheries Service Biological Opinion on operation of the Federal Columbia River Power System. This document focuses on salmon habitat, although its ecosystem-based approach necessarily affects other species as well. Salmon habitat restoration is best undertaken within the context of other biota and physical processes using an ecosystem perspective. The anticipated audience for the plan includes entities responsible for, interested in, or affected by habitat restoration in the lower Columbia River and estuary. Timeframes to apply this plan extend from the immediate (2003-2004) to the near-term (2005-2006) to the long-term (2007 and beyond). We anticipate and encourage that the plan be revised as new knowledge and experience are attained. A team comprised of the Columbia River Estuary Study Taskforce (CREST), the Lower Columbia River Estuary Partnership (Estuary Partnership), and Pacific Northwest National Laboratory (PNNL) wrote this document. The BPA and the COE, as the responsible Action Agencies, provided technical oversight. The Estuary Partnership's Science Work Group, NOAA Fisheries Habitat Conservation Division, Northwest Power Planning Council (NPPC) staff, and state and tribal fisheries management agencies reviewed drafts. The Independent Scientific Advisory Board of the NPPC reviewed and commented on the 90% draft. Revisions were incorporated into the final draft document subsequently released for public review. Extensive efforts were made to ensure a sound technical and policy basis and to solicit input from all

  5. New Bedford Harbor Superfund Project, Acushnet River Estuary engineering feasibility study of dredging and dredged-material disposal alternatives. Report 3. Characterization and elutriate testing of Acushnet River Estuary sediment. Technical report, August 1985-March 1988

    SciTech Connect

    Averett, D.E.

    1989-03-01

    Several of the alternatives being considered for the New Bedford Harbor Superfund Project involve dredging of contaminated sediment from the Acushnet River Estuary and placement of the contaminated dredged material in confined disposal areas. Evaluation of these alternatives requires testing sediment from the site to determine chemical and physical characteristics, settling properties, contaminant releases for various migration pathways, and treatment requirements for disposal area effluent. The purpose of this report is to describe the estuary composite sediment sample and the hot-spot-sediment sample tested at the US Army Engineer Waterways Experiment Station as part of the US Army Corps of Engineers' Acushnet River Estuary Engineering Feasibility Study of Dredging and Dredged Material Disposal Alternatives. Bulk sediment chemistry, physical characteristics, and elutriate testing for the sediments are included.

  6. Relationship of Caspian tern foraging ecology to nesting success in the Columbia River estuary, Oregon, USA

    USGS Publications Warehouse

    Anderson, S.K.; Roby, D.D.; Lyons, Donald E.; Collis, K.

    2007-01-01

    The prevalence of juvenile salmonids (Oncorhynchus spp.) and marine forage fishes in the diet of Caspian terns (Hydroprogne caspia) nesting in the Columbia River estuary has been established, but the relationship between diet composition, foraging distribution, and productivity of these birds has received little attention. We used radio-telemetry and on-colony observations to relate changes in off-colony distribution to patterns of colony attendance, diet composition, and productivity of adult terns nesting on East Sand Island during two years of different river and prey conditions. Average distance from the East Sand Island colony (located in the marine zone of the estuary) was 38% (6.6 km) greater in 2000 compared to 2001, associated with lower availability of marine forage fish near East Sand Island and lower prevalence of marine prey in tern diets. Colony attendance was much lower (37.0% vs. 62.5% of daylight hours), average trip duration was 40% longer (38.9 min), and nesting success was much lower (0.57 young fledged pair-1 vs. 1.40 young fledged pair-1) in 2000 compared to 2001. Higher proportions of juvenile salmonids in the diet were associated with relatively high use of the freshwater zone of the estuary by radio-tagged terns, which occurred prior to chick-rearing and when out-migrating salmonid smolts were relatively abundant. Lower availability of marine prey in 2000 apparently limited Caspian tern nesting success by markedly reducing colony attendance and lengthening foraging trips by nesting terns, thereby increasing chick mortality rates from predation, exposure, and starvation. ?? 2007 Elsevier Ltd. All rights reserved.

  7. A simple optical model to estimate suspended particulate matter in Yellow River Estuary.

    PubMed

    Qiu, Zhongfeng

    2013-11-18

    Distribution of the suspended particulate matter (SPM) concentration is a key issue for analyzing the deposition and erosion variety of the estuary and evaluating the material fluxes from river to sea. Satellite remote sensing is a useful tool to investigate the spatial variation of SPM concentration in estuarial zones. However, algorithm developments and validations of the SPM concentrations in Yellow River Estuary (YRE) have been seldom performed before and therefore our knowledge on the quality of retrieval of SPM concentration is poor. In this study, we developed a new simple optical model to estimate SPM concentration in YRE by specifying the optimal wavelength ratios (600-710 nm)/ (530-590 nm) based on observations of 5 cruises during 2004 and 2011. The simple optical model was attentively calibrated and the optimal band ratios were selected for application to multiple sensors, 678/551 for the Moderate Resolution Imaging Spectroradiometer (MODIS), 705/560 for the Medium Resolution Imaging Spectrometer (MERIS) and 680/555 for the Geostationary Ocean Color Imager (GOCI). With the simple optical model, the relative percentage difference and the mean absolute error were 35.4% and 15.6 gm(-3) respectively for MODIS, 42.2% and 16.3 gm(-3) for MERIS, and 34.2% and 14.7 gm(-3) for GOCI, based on an independent validation data set. Our results showed a good precision of estimation for SPM concentration using the new simple optical model, contrasting with the poor estimations derived from existing empirical models. Providing an available atmospheric correction scheme for satellite imagery, our simple model could be used for quantitative monitoring of SPM concentrations in YRE. PMID:24514305

  8. Determination of mass balance and entrainment in the stratified Duwamish River Estuary, King County, Washington

    USGS Publications Warehouse

    Stoner, J.D.

    1972-01-01

    During a study of the effects of waste-water input on the stratified Duwamish River estuary, intensive water-velocity and salinity measurements were made in both the lower salt wedge and the upper fresher water layer for tidal-cycle periods. The net movement of water and salt mass past a cross section during a tidal cycle was determined from integration of the measured rates of movement of water and salt past the section. The net volume of water that moved downstream past the section during the cycle agreed with the volume of fresh-water inflow at the head of the estuary within (1) 3.8 and 7.2 percent, respectively, for two studies made during periods of maximum and minimum tidal-prism thickness and identical inflow rates .of 312 cfs (cubic feet per second), and (2) 15 percent for one study made during a period of average tidal-prism thickness and an inflow rate of 1,280 cfs. For the three studies, the difference between salt mass transported upstream and downstream during the cycles ranged from 0.8 to 19 percent of the respective mean salt-mass transport. Water was entrained from the .salt-water wedge into the overlying layer of mixed fresh and salt water at tidal-cycle-average rates of 30 and 69 cfs per million square feet of interface for the inflow rates of 312 cfs, and 99 cfs per million square feet of interface for an inflow rate of 1,280 cfs. At a constant inflow rate, the rate of entrainment of salt-wedge water in the Duwamish River estuary more than doubled for a doubling of tidal-prism thickness. It also doubled for a quadrupling of inflow rate at about constant tidal-prism thickness.

  9. Relationship of Caspian tern foraging ecology to nesting success in the Columbia River estuary, Oregon, USA

    NASA Astrophysics Data System (ADS)

    Anderson, Scott K.; Roby, Daniel D.; Lyons, Donald E.; Collis, Ken

    2007-07-01

    The prevalence of juvenile salmonids ( Oncorhynchus spp.) and marine forage fishes in the diet of Caspian terns ( Hydroprogne caspia) nesting in the Columbia River estuary has been established, but the relationship between diet composition, foraging distribution, and productivity of these birds has received little attention. We used radio-telemetry and on-colony observations to relate changes in off-colony distribution to patterns of colony attendance, diet composition, and productivity of adult terns nesting on East Sand Island during two years of different river and prey conditions. Average distance from the East Sand Island colony (located in the marine zone of the estuary) was 38% (6.6 km) greater in 2000 compared to 2001, associated with lower availability of marine forage fish near East Sand Island and lower prevalence of marine prey in tern diets. Colony attendance was much lower (37.0% vs. 62.5% of daylight hours), average trip duration was 40% longer (38.9 min), and nesting success was much lower (0.57 young fledged pair -1 vs. 1.40 young fledged pair -1) in 2000 compared to 2001. Higher proportions of juvenile salmonids in the diet were associated with relatively high use of the freshwater zone of the estuary by radio-tagged terns, which occurred prior to chick-rearing and when out-migrating salmonid smolts were relatively abundant. Lower availability of marine prey in 2000 apparently limited Caspian tern nesting success by markedly reducing colony attendance and lengthening foraging trips by nesting terns, thereby increasing chick mortality rates from predation, exposure, and starvation.

  10. Continuous resistivity profiling and seismic-reflection data collected in 2006 from the Potomac River Estuary, Virginia and Maryland

    USGS Publications Warehouse

    Cross, V.A.; Foster, D.S.; Bratton, J.F.

    2010-01-01

    In 2006 the U.S. Geological Survey conducted a geophysical survey on the Chesapeake Bay and the Potomac River Estuary in order to test hypotheses about groundwater flow under and into Chesapeake Bay. Resource managers are concerned about nutrients that are entering the estuary via submarine groundwater discharge and are contributing to eutrophication. The research carried out as part of this study was designed to help refine nutrient budgets for Chesapeake Bay by characterizing submarine groundwater flow and groundwater discharge beneath part of the bay?s mainstem and a major tributary, the Potomac River Estuary. The data collected indicate that plumes of reduced-salinity groundwater are commonly present along the shorelines of Chesapeake Bay and the Potomac River Estuary. Data also show that buried paleochannels generally do not serve as conduits for flow of groundwater from land to underneath the bay and estuary but rather may focus discharge of reduced-salinity water along their flanks, and provide routes for migration of saltwater into the sediments.

  11. Three-dimensional simulation of flow, salinity, sediment, and radionuclide movements in the Hudson River estuary

    SciTech Connect

    Onishi, Y.; Trent, D.S.

    1985-04-01

    The three-dimensional, finite difference model, FLESCOT simulates time-varying movements of flow, turbulent kinetic energy, salinity, water temperature, sediment, and contaminants in estuarine, coastal, and ocean waters. The model was applied to a 106-km (66-mi) reach of the Hudson River estuary in New York between Chelsea and the mouth of the river. It predicted the time-varying, three-dimensional distributions of tidal flow, salinity, three separate groups of sediments (i.e., sand, silt, and clay), and a radionuclide (/sup 137/Cs) in both dissolved and particulate (those sorbed by sediments) forms for over 40 days. The model also calculated riverbed elevation changes caused by sediment deposition and bed erosion, bed sediment size distribution and armoring, and distributions of the particulate /sup 137/Cs sorbed by sand, silt, and clay in the bed.

  12. Picoplankton and virioplankton abundance and community structure in Pearl River Estuary and Daya Bay, South China.

    PubMed

    Ni, Zhixin; Huang, Xiaoping; Zhang, Xia

    2015-06-01

    By using flow cytometry techniques, we investigated the abundance and composition of the heterotrophic prokaryotes, virioplankton and picophytoplankton community in the Pearl River Estuary and Daya Bay in the summer of 2012. We identified two subgroups of prokaryotes, high nucleic acid (HNA) and low nucleic acid (LNA), characterized by different nucleic acid contents. HNA abundance was significantly correlated with larger phytoplankton and Synechococcus (Syn) abundance, which suggested the important role of organic substrates released from primary producers on bacterial growth. Although LNA did not show any association with environmental variables, it was a vital component of the microbial community. In contrast to previous studies, the total virioplankton concentration had a poor relationship with nutrient availability. The positive relationship between large-sized phytoplankton abundance and the V-I population confirmed that V-I was a phytoplankton-infecting viral subgroup. Although the V-II group (bacteriophages) was dominant in the virioplankton community, it was not related with prokaryotic abundance, which indicated factors other than hosts controlling V-II abundance or the uncertainty of virus-host coupling. With respect to the picophytoplankton community, our results implied that river input exerted a strong limitation to Syn distribution in the estuary, while picoeukaryotes (Euk) were numerically less abundant and showed a quite different distribution pattern from that of Syn, and hence presented ecological properties distinct from Syn in our two studied areas. PMID:26040741

  13. Ecosystem Health Assessment in the Pearl River Estuary of China by Considering Ecosystem Coordination

    PubMed Central

    Chen, Xiaoyan; Gao, Huiwang; Yao, Xiaohong; Chen, Zhenhua; Fang, Hongda; Ye, Shufeng

    2013-01-01

    Marine ecosystem is a complex nonlinear system. However, ecosystem health assessment conventionally builds on a linear superposition of changes in ecosystem components and probably fails to evaluate nonlinear interactions among various components. To better reflect the intrinsic interactions and their impacts on ecosystem health, an ecosystem coordination index, defined as the matching level of ecosystem structure/services, is proposed and incorporated into the ecosystem health index for a systematic diagnosis in the Pearl River Estuary, China. The analysis results show that the ecosystem health index over the last three decades decreased from 0.91 to 0.50, indicating deteriorating from healthy to unhealthy status. The health index is 3–16% lower than that calculated using the common method without considering ecosystem coordination. Ecosystem health degradation in the Pearl River Estuary manifested as significant decreases in structure/services and somewhat mismatching among them. Overall, the introduction of coordination in ecosystem health assessment could improve the understanding of the mechanism of marine ecosystem change and facilitate effective restoration of ecosystem health. PMID:23894670

  14. Seasonal changes in the demersal nekton community off the Changjiang River estuary

    NASA Astrophysics Data System (ADS)

    Jiang, Yazhou; Ling, Jianzhong; Li, Jiansheng; Yang, Linlin; Li, Shengfa

    2014-03-01

    The diversity, community structure and seasonal variation in demersal nekton off the Changjiang (Yangtze) River estuary was evaluated using monthly trawl survey data, collected between December 2008 and November 2009. A total of 95 species (56 teleosts, 11 cephalopods, and 28 decapod crustaceans) from 69 genera, 49 families and 15 orders were collected. These species could be classified into six groups on the basis of temporal distribution patterns. The resident crab Ovalipes punctatus dominated the community, both in number and biomass. A clear seasonal succession was observed in the species composition. Cluster analysis revealed three primary seasonal groups corresponding to the samples collected in winter-spring, late spring-summer and late summer-autumn. The highest biomass and lowest diversity were observed in summer, while the lowest biomass and highest diversity in winter. The abundance-biomass comparison curves and community composition suggested that the investigated community was moderately disturbed. The results suggest that reduction in fishing pressure and in the degree of seasonal hypoxia are essential for sustainable resource management off the Changjiang River estuary.

  15. Seasonal air-water exchange fluxes of polychlorinated biphenyls in the Hudson River Estuary.

    PubMed

    Yan, Shu; Rodenburg, Lisa A; Dachs, Jordi; Eisenreich, Steven J

    2008-03-01

    Polychlorinated biphenyls (PCBs) were measured in the air and water over the Hudson River Estuary during six intensive field campaigns from December 1999 to April 2001. Over-water gas-phase SigmaPCB concentrations averaged 1100 pg/m3 and varied with temperature. Dissolved-phase SigmaPCB concentrations averaged 1100 pg/L and displayed no seasonal trend. Uncertainty analysis of the results suggests that PCBs with 5 or fewer chlorines exhibited net volatilization. The direction of net air/water exchange could not be determined for PCBs with 6 or more chlorines. Instantaneous net fluxes of SigmaPCBs ranged from +0.2 to +630 ng m(-2) d(-1). Annual fluxes of SigmaPCBs were predicted from modeled gas-phase concentrations, measured dissolved-phase concentrations, daily surface water temperatures and wind speeds. The net volatilization flux was +62 microg m(-2) yr(-1), corresponding to an annual loss of +28 kg/yr of SigmaPCBs from the Hudson River Estuary for the year of 2000. PMID:17854962

  16. [Temporal and spatial distribution of red tide in Yangtze River Estuary and adjacent waters].

    PubMed

    Liu, Lu-San; Li, Zi-Cheng; Zhou, Juan; Zheng, Bing-Hui; Tang, Jing-Liang

    2011-09-01

    The events of red tide were collected in Yangtze River Estuary and adjacent waters from 1972 to 2009. Based on geographic information system (GIS) analysis on the temporal and spatial distribution of red tide, the distribution map was generated accordingly. The results show: (1) There are three red tide-prone areas, which are outside the Yangtze River estuary and the eastern of Sheshan, Huaniaoshan-Shengshan-Gouqi, Zhoushan and the eastern of Zhujiajian. The red tide occurred 174 times in total, in which there were 25 times covered the area was larger than 1 000 km2. After 2000, the frequency of red tide were significantly increasing; (2) The frequent occurrence of red tide was in May (51% of total occurrence) and June (20% of total occurrence); (3) In all of the red tide plankton, the dominant species were Prorocentrum danghaiense, Skeletonema costatum, Prorocentrum dantatum, Nactiluca scientillans. The red tides caused by these species were 38, 35, 15, 10 times separately. PMID:22165212

  17. Toxicological relevance of endocrine disruptors in the Tagus River estuary (Lisbon, Portugal).

    PubMed

    Rocha, Maria João; Cruzeiro, Catarina; Reis, Mário; Pardal, Miguel Ângelo; Rocha, Eduardo

    2015-08-01

    The Tagus is the longest Iberian river, notwithstanding, the levels of natural and xenoestrogenic endocrine-disrupting compounds (EDCs) were never measured in its estuary. Suspecting for their presence, we made a major survey of 17 EDCs that include: (i) natural (17β-oestradiol and estrone) and pharmaceutical oestrogens (17α-ethynylestradiol); (ii) industrial and household pollutants (octylphenols, nonylphenols and their mono and diethoxylates, and bisphenol A); (iii) phytoestrogens (biochanin A, daidzein, formononetin, genistein); and (iv) the phytosterol (sitosterol). Water samples from the Tagus estuary were taken from nine locations every 2 months over a 1-year period and analysed by gas chromatography. Oestrogens, industrial/household pollutants were consistently higher at two sites-at Tagus River mouth and close to the Trancão tributary, both at Lisbon region. The overall oestrogenic load, in ethynylestradiol equivalents, was 13 ng/L for oestrogens, 2.3 ng/L for industrial/household pollutants and 43 ng/L for phytoestrogens; well in the range of toxicological significance. Water physicochemical parameters also indicated anthropogenic pollution, mainly at the two above-referred sampling sites. PMID:26135642

  18. Evaluating Cumulative Ecosystem Response to Restoration Projects in the Lower Columbia River and Estuary, 2009

    SciTech Connect

    Johnson, Gary E.; Diefenderfer, Heida L.; Borde, Amy B.; Bryson, Amanda J.; Cameron, April; Coleman, Andre M.; Corbett, C.; Dawley, Earl M.; Ebberts, Blaine D.; Kauffman, Ronald; Roegner, G. Curtis; Russell, Micah T.; Silva, April; Skalski, John R.; Thom, Ronald M.; Vavrinec, John; Woodruff, Dana L.; Zimmerman, Shon A.

    2010-10-26

    This is the sixth annual report of a seven-year project (2004 through 2010) to evaluate the cumulative effects of habitat restoration actions in the lower Columbia River and estuary (LCRE). The project, called the Cumulative Effects Study, is being conducted for the U.S. Army Corps of Engineers Portland District (USACE) by the Marine Sciences Laboratory of the Pacific Northwest National Laboratory (PNNL), the Pt. Adams Biological Field Station of the National Marine Fisheries Service (NMFS), the Columbia River Estuary Study Taskforce (CREST), and the University of Washington. The goal of the Cumulative Effects Study is to develop a methodology to evaluate the cumulative effects of multiple habitat restoration projects intended to benefit ecosystems supporting juvenile salmonids in the 235-km-long LCRE. Literature review in 2004 revealed no existing methods for such an evaluation and suggested that cumulative effects could be additive or synergistic. From 2005 through 2009, annual field research involved intensive, comparative studies paired by habitat type (tidal swamp versus marsh), trajectory (restoration versus reference site), and restoration action (tidegate replacement vs. culvert replacement vs. dike breach).

  19. Water resources of the Little Fork River watershed, northeastern Minnesota

    USGS Publications Warehouse

    Helgesen, John O.; Lindholm, Gerald F.; Ericson, Donald W.

    1976-01-01

    The Little Fork River watershed is one of 39 watershed units designated by the Minnesota Department of Natural Resources for evaluation of the State 's water resources. Included is an appraisal of the occurrence, quantity, quality, and availability of ground and surface waters. Water resources are not intensively developed anywhere in the watershed. Essentially all water used is withdrawn from ground-water sources, mainly glacial drift, which ranges from 0 to over 200 feet (61 meters) in thickness. Buried sand and gravel in the drift is the most favorable source for development. Most ground water is of the calcium or calcium magnesium bicarbonate type. The degree of mineralization generally increases downgradient in the flow system. Ground water is commonly very hard and high in iron and manganese. Lakes and wetlands have a natural regulating effect on streamflow. Water in streams is of the calcium bicarbonate type. The amount of mineralization reflects surficial geology, being greatest in streams draining glacial-lake sediments and least in streams draining areas of sand lakes. Color and iron concentration in stream waters generally exceed recommended domestic consumption limits.

  20. Predicted effects of proposed navigation improvements on residence time and dissolved oxygen of the salt wedge in the Duwamish River estuary, King County, Washington

    USGS Publications Warehouse

    Haushild, W.L.; Stoner, J.D.

    1973-01-01

    A model of the circulation and quality of water in the Duwamish River estuary has been sufficiently developed to allow prediction of the effects of a proposed widening and deepening of waterways on residence time and dissolved oxygen in the estuary's salt wedge. For a low river-discharge period in August 1970, use of the model yielded an estimated residence time of wedge water to be 6.3 days in the present waterways estuary and 8.6 days in the wider and deeper proposed-waterways estuary--a 37-percent increase. June-September 1970 and for the estuary about 4 miles upstream from its mouth, the model estimates indicate that dissolved-oxygen values in the wedge of the proposed-waterways estuary would be as much as 1.4 milligrams per liter lower and would average 0.4 milligram per liter lower than (average difference significant at 95-percent confidence level) dissolved-oxygen values in the wedge of the present-waterways estuary. Extrapolation to low dissolved-oxygen values of a regression between the predicted dissolved oxygen for both the proposed and present-waterways estuaries suggests that 4 miles upstream of the estuary mouth oxygen would be completely depleted from the proposed-waterways estuary wedge whereas there still would be 0.2 milligram of oxygen per liter of water in the wedge of the present-waterways estuary.

  1. Nutrient exchange across the sediment-water interface in the Potomac River estuary

    USGS Publications Warehouse

    Callender, E.; Hammond, Douglas E.

    1982-01-01

    The flux of ammonia, phosphate, silica and radon-222 from Potomac tidal river and estuary sediments is controlled by processes occurring at the sediment-water interface and within surficial sediment. Calculated diffusive fluxes range between 0??6 and 6??5 mmol m-2 day-1 for ammonia, 0??020 and 0??30 mmol m-2 day-1 for phosphate, and 1??3 and 3??8 mmol m-2 day-1 for silica. Measured in situ fluxes range between 1 and 21 mmol m-2 day-1 for ammonia, 0??1 and 2??0 mmol m-2 day-1 for phosphate, and 2 and 19 mmol m-2 day-1 for silica. The ratio of in situ fluxes to diffusive fluxes (flux enhancement) varied between 1??6 and 5??2 in the tidal river, between 2??0 and 20 in the transition zone, and from 1??3 to 5??1 in the lower estuary. The large flux enhancements from transition zone sediments are attributed to macrofaunal irrigation. Nutrient flux enhancements are correlated with radon flux enhancements, suggesting that fluxes may originate from a common region and that nutrients are regenerated within the upper 10-20 cm of the sediment column. The low fluxes of phosphate from tidal viver sediments reflect the control benthic sediment exerts on phosphorus through sorption by sedimentary iron oxyhydroxides. In the tidal river, benthic fluxes of ammonia and phosphate equal one-half and one-third of the nutrient input of the Blue Plains sewage treatment plant. In the tidal Potomac River, benthic sediment regeneration supplies a significant fraction of the nutrients utilized by primary producers in the water column during the summer months. ?? 1982.

  2. Sources and fate of bioavailable dissolved organic nitrogen in the Neuse River Estuary, North Carolina

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    Eutrophication is a widespread problem affecting the structure and function of estuaries and is often linked to anthropogenic nitrogen (N) enrichment, since N is the primary nutrient limiting algal production. Watershed management actions typically have ignored dissolved organic nitrogen (DON) loading because of its perceived refractory nature and instead focused on inorganic N as targets for loading reductions. A fluorescence-based model indicated that anthropogenic sources of DON near the head of the microtidal Neuse River Estuary (NRE), NC were dominated by septic systems and poultry waste. A series of bioassays were used to determine the bioavailability of river DON and DON-rich sources to primary producers and whether those additions promoted the growth of certain phytoplankton taxa, particularly harmful species. Overall, at time scales up to two to three weeks, estuarine phytoplankton and bacteria only showed limited responses to additions of high molecular weight (HMW, >1 kDa) river DON. When increases in productivity and biomass did occur, they were quite small compared with the response to inorganic N. Low molecular weight (LMW) river DON, waste water treatment plant effluent, and poultry litter extract did have a positive effect on phytoplankton and bacterial production, indicating a bioavailable fraction. High variability of bulk DON concentration suggested that bioavailable compounds added in the experimental treatments were low in concentration and turned over quite rapidly. Some phytoplankton taxa, as measured by diagnostic photopigments, appeared to be selectively enhanced by the HMW and specific source DON additions, although the taxa could not be positively identified as harmful species. Preliminary tests show that labile autochthonous organic matter may act as a primer for the mineralization of the HMW DON. These and other, longer-term bioavailability studies will be needed to adequately address the fate of watershed DON in estuarine ecosystems.

  3. Nutrient exchange across the sediment-water interface in the Potomac River estuary

    NASA Astrophysics Data System (ADS)

    Callender, Edward; Hammond, Douglas E.

    1982-10-01

    The flux of ammonia, phosphate, silica and radon-222 from Potomac tidal river and estuary sediments is controlled by processes occurring at the sediment-water interface and within surficial sediment. Calculated diffusive fluxes range between 0·6 and 6·5 mmol m -2 day -1 for ammonia, 0·020 and 0·30 mmol m -2 day -1 for phosphate, and 1·3 and 3·8 mmol m -2 day -1 for silica. Measured in situ fluxes range between 1 and 21 mmol m -2 day -1 for ammonia, 0·1 and 2·0 mmol m -2 day -1 for phosphate, and 2 and 19 mmol m -2 day -1 for silica. The ratio of in situ fluxes to diffusive fluxes (flux enhancement) varied between 1·6 and 5·2 in the tidal river, between 2·0 and 20 in the transition zone, and from 1·3 to 5·1 in the lower estuary. The large flux enhancements from transition zone sediments are attributed to macrofaunal irrigation. Nutrient flux enhancements are correlated with radon flux enhancements, suggesting that fluxes may originate from a common region and that nutrients are regenerated within the upper 10-20 cm of the sediment column. The low fluxes of phosphate from tidal viver sediments reflect the control benthic sediment exerts on phosphorus through sorption by sedimentary iron oxyhydroxides. In the tidal river, benthic fluxes of ammonia and phosphate equal one-half and one-third of the nutrient input of the Blue Plains sewage treatment plant. In the tidal Potomac River, benthic sediment regeneration supplies a significant fraction of the nutrients utilized by primary producers in the water column during the summer months.

  4. Paleoenvironmental and paleoclimatic conditions in the Tagus River Estuary during the Holocene

    NASA Astrophysics Data System (ADS)

    Santos, Célia; Abrantes, Fátima; Rodrigues, Teresa; Voelker, Antje; Vis, Geert-Jan

    2010-05-01

    Estuaries constitute the frontier between terrestrial, fluvial and marine environments, representing areas of high biological productivity that are particularly sensitive to global, regional and local environmental and climatic changes. The lower Tagus valley experienced a transgression period from 12000 - 7000 calendar (cal) years BP (Vis et al., 2008;QSR). Trying to understand the interaction between land-river and ocean, we are studying paleoenvironmental conditions of the Tagus river estuary, using a 52,76 m long core drilled near Vila Franca de Xira (38°56´24´´N; 8°56´19´´W, 2 meters elevation). The age model of this core is based on 6 AMS 14C dates. Marine/estuarine productivity and river input have been reconstructed for the last 14 000 calendar years BP, using a high resolution, multi-proxy study of diatoms, C37 alkenones, higher plant C23 - C33 n-alkanes and C20 - C30 n-alkan-1-ols, Fe and Ca content derived from XRF analysis and Total Organic Carbon (TOC). Our data shows that major river input events (as revealed by higher concentrations of terrestrial lipid biomarkers and phytoliths) control the primary productivity at this site because increased productivity - maxima in diatoms, C37 alkenones and TOC - are synchronous. Marine and brackish diatom genera and C37 alkenones occur between ca. 11500- 4500 cal years BP indicating a marine to brackish environment, probably in a shallow marine pro-delta. After 4500 cal years sea level had risen so much that the marine influence was reduced (low abundance of marine diatoms) and the environmental was similar to the modern, i.e., a brackish tidal flat. Further work is needed to improve the understanding of this estuarine record.

  5. Autonomous Acoustic Receiver Deployment and Mooring Techniques for Use in Large Rivers and Estuaries

    SciTech Connect

    Titzler, P. Scott; McMichael, Geoffrey A.; Carter, Jessica A.

    2010-08-01

    Autonomous acoustic receivers are often deployed across a range of aquatic habitats to study aquatic species. The Juvenile Salmon Telemetry System autonomous acoustic receiver packages we deployed in the Columbia River and its estuary were comprised of an acoustic receiver, acoustic release, and mooring line sections and were deployed directly on the river bottom. Detection ranges and reception data from past optimization deployments helped determine acoustic receiver spacing in order to achieve acceptable detection probabilities for juvenile salmon survival estimation. Methods used in 2005, which resulted in a high equipment loss rate, were modified and used between 2006 and 2008 to increase crew safety and optimize receiver deployment and recovery operations in a large river system. By eliminating surface buoys and taglines (for anchor recovery), we experienced a recovery success rate greater than previous acoustic receiver deployment techniques used in the Columbia River and elsewhere. This autonomous acoustic receiver system has optimized deployment, recovery, and servicing efficiency to successfully detect acoustic-tagged salmonids in a variety of river environments.

  6. Economic compensation standard for irrigation processes to safeguard environmental flows in the Yellow River Estuary, China

    NASA Astrophysics Data System (ADS)

    Pang, Aiping; Sun, Tao; Yang, Zhifeng

    2013-03-01

    SummaryAgriculture and ecosystems are increasingly competing for water. We propose an approach to assess the economic compensation standard required to release water from agricultural use to ecosystems while taking into account seasonal variability in river flow. First, we defined agricultural water shortage as the difference in water volume between agricultural demands and actual supply after maintaining environmental flows for ecosystems. Second, we developed a production loss model to establish the relationship between production losses and agricultural water shortages in view of seasonal variation in river discharge. Finally, we estimated the appropriate economic compensation for different irrigation stakeholders based on crop prices and production losses. A case study in the Yellow River Estuary, China, demonstrated that relatively stable economic compensation for irrigation processes can be defined based on the developed model, taking into account seasonal variations in river discharge and different levels of environmental flow. Annual economic compensation is not directly related to annual water shortage because of the temporal variability in river flow rate and environmental flow. Crops that have stable planting areas to guarantee food security should be selected as indicator crops in economic compensation assessments in the important grain production zone. Economic compensation may be implemented by creating funds to update water-saving measures in agricultural facilities.

  7. Factors initiating phytoplankton blooms and resulting effects on dissolved oxygen in Duwamish River estuary, Seattle, Washington

    USGS Publications Warehouse

    Welch, Eugene Brummer

    1969-01-01

    Phytoplankton productivity, standing stock, and related environmental factors were studied during 1964-66 in the Duwamish River estuary, at Seattle, Wash., to ascertain the factors that affect phytoplankton growth in the estuary; a knowledge of these factors in turn permits the detection and evaluation of the influence that effluent nutrients have on phytoplankton production. The factors that control the concentration of dissolved oxygen were also evaluated because of the importance of dissolved oxygen to the salmonid populations that migrate through the estuary. Phytoplankton blooms, primarily of diatoms, occurred in the lower estuary during August 1965 and 1966. No bloom occurred during 1964, but the presence of oxygen-supersaturated surface water in August 1963 indicates that a bloom did occur then. Nutrients probably were not the primary factor controlling the timing of phytoplankton blooms. Ammonia ,and phosphate concentrations increased significantly downstream from the Municipality of Metropolitan Seattle's Renton Treatment Plant outfall after the plant began operation in June 1965, and concentrations of nitrogen and phosphorus were relatively high before operation of the Renton Treatment Plant and during nonbloom periods. The consistent coincidence of blooms with minimum fresh-water discharge and tidal exchange during August throughout the study period indicates that bloom timing probably was controlled mostly by hydrographic factors that determine retention time and stability of the surface-water layer. This control was demonstrated in part by a highly significant correlation of gross productivity with retention time (as indicated by fresh-water discharge) and vertical stability (as indicated by the difference between mean surface and mean bottom temperatures). The failure of a bloom to develop in 1964 is related to a minimum fresh-water discharge that was much greater than normal during that summer. Hydrographic factors are apparently important because

  8. Heavy metal spatial variability and historical changes in the Yangtze River estuary and North Jiangsu tidal flat.

    PubMed

    Liu, Zhiyong; Pan, Shaoming; Sun, Zhuyou; Ma, Renfeng; Chen, Lanhua; Wang, Yanlong; Wang, Shuao

    2015-09-15

    This research focuses on the spatial and temporal patterns of heavy metals from the Yangtze River estuary and the tidal flat of north Jiangsu. Most heavy metals in the surficial sediments after normalization to Ti decreased seaward at the Yangtze River estuary. The core records showed that the heavy metal variations in the last 50years were primarily linked to natural weathering input of trace elements. However, significant heavy metal pollution (mainly Ni, Pb, Cd, Cu and As) were in the two study areas, with anthropogenic inventories accounting for 23-40% percent of the total pollution. Sequential extraction showed that Pb, Cu and Ni were present largely in the non-residual fraction, which indicated the potential bioavailability in the study areas. The SEM/EDS together with sequential extraction facilitated the easy tracing of the origin/sources of heavy metals in a simple way in the estuary and the tidal flat. PMID:26159727

  9. Identifying the breeding areas of locusts in the Yellow River estuary using Landsat ETM+ imagery

    NASA Astrophysics Data System (ADS)

    Liu, Qingsheng; Liu, Gaohuan; Yang, Yuzhen; Liu, Peng; Huang, Jianjie

    2006-03-01

    The Yellow River Estuary became an important plague region of locusts because of its special geographic location. Many years' survey data showed that the environment was the chief factor that influenced locust pest occurring. In the recent years, because the amount of water from the Yellow River and precipitation reduced and distributed asymmetrically, and soil salinization became serious much more, and many farmlands went out of cultivation, which improved the habitats for locusts, the plague of locusts happened frequently under condign climate. The field survey data from 1991 to 2000 showed that the plague of locust became more aggravating year after year. Therefore, it is important to monitor and control the plague of locusts. According to many years' investigation data analysis, got the condign habitat conditions for Locusta Migratoria Manilensis (Meyen) in the Yellow River Estuary. So the breeding areas of locusts monitoring with remote sensing imagery was to identify those regions according to the condign habitat conditions. Landsat ETM+ imagery (2000-05-02) data was chosen to identify the breeding areas of locusts in the Yellow River Estuary. Firstly classified Landsat TM imagery (2000-5-2) and extract reed lands and lawn lands and slightly salinized soils. Secondly made mask images through transforming these three raster classes into vector layers, then calculated a anti-atmospheric visible light vegetation index VARIg = (B2-B3)/(B2+B3-B1). According to field investigation data of vegetation fractional cover in 2000, got the relationship between vegetation fractional cover and VARIg values, 70% to 3.0, 50% to 2.3. As a result, the infrequent areas were where VARIg values were great than 3.0, and the moderate areas were where VARIg values were between 2.3 and 3.0, and frequent areas were where VARIg values were under 2.3. According to statistical analysis, the infrequent areas were percent 10 of the lands that have the condign soil salt content for locust

  10. Emergy and Economic Evaluations of Four Fruit Production Systems on Reclaimed Wetlands Surrounding the Pearl River Estuary, China

    EPA Science Inventory

    Emergy and economic methods were used to evaluate and compare a traditional tropical fruit cultivation system, for bananas, and three newly introduced fruit cultivation systems, for papaya, guava and wampee, on reclaimed wetlands of the Pearl River Estuary, China. The evaluations...

  11. Long-term Changes in Water Quality and Productivity in the Patuxent River Estuary: 1985 to 2003

    EPA Science Inventory

    We conducted a quantitative assessment of estuarine ecosystem responses to reduced phosphorus and nitrogen loading from sewage treatment facilities and to variability in freshwater flow and non-point nutrient inputs to the Patuxent River estuary. We analyzed a 19-year data set o...

  12. [Distribution of Nitrogen and Phosphorus in the Tidal Reach and Estuary of the Daliao River and Analysis of Potential Eutrophication].

    PubMed

    Zhang, Lei; Cao, Wei; Ma, Ying-qun; Han, Chao-nan; Qin, Yan-wen; Zhao, Yan-min; Liu, Zhi-chao; Yang, Cheng-cheng

    2016-05-15

    Based on the monitoring data in the tidal reach and estuary of the Daliao river in August and November, 2013, the seasonal and spatial distribution of the nitrogen and phosphorus forms were studied, and the degree of eutrophication was evaluated. The results showed that nitrate nitrogen was the main chemical species and occupied about fifty-five percent of inorganic nitrogen, and the particulate phosphorus was the main chemical species and occupied about fifty percent of total phosphorus in the tidal reach and estuary of the Daliao river in wet and dry seasons, 2013. The concentrations of nitrogen and phosphorus nutrients decreased in the direction from tidal reach to estuary of the Daliao river. Correlation analysis showed that there was a significant negative correlation between the nitrogen and phosphorus forms and salinity in most of the water body, which illustrated that physical dilution of seawater played a major role in the spatial distribution of nitrogen and phosphorus forms. The concentrations of nitrogen and phosphorus nutrients in the dry season were higher than those in the wet season, this was mainly related to the seasonal terrestrial input of the tidal reach. The concentration of the dissolved inorganic nitrogen was higher than 0.30 mg · L⁻¹, and the value of N/P was higher than 60, which indicated that PO₄³⁻-P was the nutrient limiting phytoplankton growth in the tidal reach and estuary of the Daliao river in August and November, 2013. PMID:27506019

  13. A survey of the St. Louis River estuary with emphasis on non-indigenous species and habitat structure

    EPA Science Inventory

    As part of a larger study to develop a monitoring network for aquatic non-indigenous species (NIS), a comprehensive multi-gear survey of larval fish and macroinvertebrates in the St. Louis River estuary was conducted during summer 2012. A total of 139 larval fish samples and 118...

  14. Shoreline Classification of the St. Louis River Estuary using Geographic Information Systems and Standard Landuse/Landcover Data Sets

    EPA Science Inventory

    The St. Louis River Estuary (SLRE) shoreline is ~300 km in length and borders MN and WI from the MN highway 23 downstream to Lake Superior. The shoreline is a complex and diverse mixture of many features from industrial docks and slips in the lower SLRE to complex wetlands and na...

  15. A decade of aquatic invasive species (AIS) early detection method development in the St. Louis River estuary

    EPA Science Inventory

    As an invasion prone location, the St. Louis River Estuary (SLRE) has been a case study for ongoing research to develop the framework for a practical Great Lakes monitoring network for early detection of aquatic invasive species (AIS). Early detection, however, necessitates findi...

  16. Bacterial abundance and aerobic microbial activity across natural and oyster aquaculture habitats during summer conditions in a northeastern Pacific estuary.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We measured sediment properties and the abundance and functional diversity of microbes in Willapa Bay, Washington, USA, to test the response of sediment microbes to oyster aquaculture. Sites spanned the estuary gradient (salinity 24-30) and six different habitat types: eelgrass (Zostera marina), uns...

  17. Alternative and Legacy Perfluoroalkyl Substances: Differences between European and Chinese River/Estuary Systems.

    PubMed

    Heydebreck, Franziska; Tang, Jianhui; Xie, Zhiyong; Ebinghaus, Ralf

    2015-07-21

    The production and use of long-chain perfluoroalkyl substances (PFASs) must comply with national and international regulations. Driven by increasingly stringent regulations, their production has been outsourced to less regulated countries in Asia. In addition, the fluoropolymer industry started to use fluorinated alternatives, such as 2,3,3,3-tetrafluoro-2-(1,1,2,2,3,3,3-heptafluoropropoxy)propanoic acid (HFPO-DA). Between August 2013 and September 2014, we investigated the occurrence and distribution of HFPO-DA and legacy PFASs in surface waters of the following river/estuary systems: the Elbe and Rhine Rivers in Germany, the Rhine-Meuse delta in The Netherlands, and the Xiaoqing River in China. Distinct differences were revealed among the study areas; notably, the Chinese samples were highly polluted by an industrial point source discharging mainly perfluorooctanoic acid (PFOA). This particular point source resulted in concentrations more than 6000 times higher than an industrial point source observed in the Scheur River, where HFPO-DA was the dominant compound with a concentration of 73.1 ng/L. Moreover, HFPO-DA was detected in all samples along the coastline of the North Sea, indicating that the compound may be transported from the Rhine-Meuse delta into the German Bight via the water current. To the best of our knowledge, the fluorinated alternative, HFPO-DA, was detected for the first time in surface waters of Germany and China. PMID:26106903

  18. [Distribution and partition of polycyclic aromatic hydrocarbons in surface water from the Pearl River estuary].

    PubMed

    Luo, Xiao-jun; Chen, She-jun; Yu, Mei; Mai, Bi-xian; Sheng, Guo-ying; Fu, Jia-mo

    2008-09-01

    To obtain the temporal and spatial distribution and partition of PAH between water and particles in coastal area, water samples were collected from the Pearl River Estuary in July 2002 (summer) and April 2003 (spring) and polycyclic aromatic hydrocarbons (PAHs) were analysed with GC-MS in the present study. Total PAH concentrations in water samples were higher in spring (c(p): 4.0-39.1 ng/L; c(w): 15.9-184.2 ng/L) than in summer (c(p): 2.6-26.6 ng/L; c(w): 13.0-28.3 ng/L). Suspended particle matter (SPM) content, photogradation and riverine discharge were the major factors controlling the PAH concentrations in water. The 3-ring PAHs were the dominant PAHs in water samples. The 5 and 6 ring PAHs are more enriched in the inner estuary samples than in outside estuary samples, and the 3 ring PAHs are more enriched in summer samples than in spring samples. The differences in composition and source of SPM might be responsible for this observation. The partition coefficient (Kp) increased with the particular organic carbon content of SPM and salinity of water and decreased with the SPM content of samples, which were consistent with the PAH partition theory. A linear correlation between IgK(OC) and lgK(OW) were found in two sampling periods. The observed values of lgK(OC) exceed their predicted values calculated form linear free energy relationship between lgK(OC) and lgK(OW). PMID:19068615

  19. Avulsion at a drift-dominated mesotidal estuary: The Chubut River outlet, Patagonia, Argentina

    NASA Astrophysics Data System (ADS)

    Isla, Federico; Espinosa, Marcela; Rubio, Belén; Escandell, Alejandra; Gerpe, Marcela; Miglioranza, Karina; Rey, Daniel; Vilas, Federico

    2015-10-01

    The Chubut River flows from the Andes to the Atlantic Ocean, and is interrupted by a single dam built at the middle valley. The lower valley is dominated by the aggradation of an alluvial plain induced by a complex of spits that enclosed the inlet in the last 5000 years. The river has reduced its flow because the blocking of the upper basin by terminal moraines during the Upper Pleistocene. At least the last two marine transgressions have flooded this estuary, and contributed to the aggradation during regressions. The area is of particular interest in regard to irrigation channels practiced since the XIX century. Today, the mean monthly flow is less than 10 m3/s although peaks of 95 m3/s have been recorded in Gaiman in July 2001. The dynamics of the estuary is dominated by waves (wave-dominated estuary) as tidal effects attenuate in less than 5 km. Three vibracores were collected within this floodplain: (a) at Gaiman, an area without any effect of the sea (35 km from the coast); (b) at Trelew, at the former avulsion plain of the river (18 km from the coast); and (c) at Playa Magagna, a saltmarsh located 0.4 km from the beach. At the Gaiman core (1.54 m long) fresh-water epiphytic diatoms dominate (Epithemia sorex, Cocconeis placentula, Ulnaria ulna) suggesting the aggradation of an alluvial plain. The Trelew core (2.19 m long) was collected from a deltaic plain. It was composed by fine sand with organic matter at the base that evolved into silty layers to the top. Several unconformities and laminae with heavy minerals were detected by their geochemical composition analysed by micro X-ray fluorescence (Itrax XRF core scanner). Fine-sand laminated layers were perfectly detected by their high content in S and Cl. On the other hand, mud layers presented lower content in Mg and Al with increments in Ca and V. The core from the marsh area (1.67 m long) was analysed in terms of the diatom evolution in order to detect Holocene sea-level and salinity effects. The sand flats

  20. Modeling the transport of freshwater and dissolved organic carbon in the Neuse River Estuary, NC, USA following Hurricane Irene (2011)

    NASA Astrophysics Data System (ADS)

    Brown, Matthew M.; Mulligan, Ryan P.; Miller, Richard L.

    2014-02-01

    Numerical models are useful tools that aid in understanding complex flows and the distribution of suspended material over large geographic areas and during extreme weather events. Here we describe the use of a three-dimensional numerical model (Delft3D) to simulate freshwater and dissolved organic carbon (DOC) transport over a 3-week period, following intense precipitation that led to high river discharge into the brackish Neuse River Estuary (NRE), NC, from Hurricane Irene (Aug. 2011). The model was calibrated and validated using field measurements of water level elevations, vertical salinity profiles, and surface DOC concentrations in the estuary. DOC was simulated as a conservative tracer over the study period. Model results indicate differences in the intensity of the freshwater and DOC-laden plumes as they propagated along estuary due to a one week time lag between the maximum discharge of 540 m3 s-1 and maximum DOC concentration of 29.85 mg L-1 entering the NRE from the river. In the upper estuary, the surface DOC concentration increased by 18 mg L-1 above the pre-storm value of 7 mg L-1; the maximum concentration occurred 10 days after the passage of the storm. In the lower estuary, the outer edge of the DOC plume reached Pamlico Sound after 3 weeks with a surface DOC concentration that was 3 mg L-1 above the pre-storm value. Results also indicate cross-channel salinity differences up to 10 ppt and DOC concentration differences up to 15 mg L-1 in the upper NRE to due to wind-driven motion of the estuary. The methods described here could be applied to other coastal plain estuarine systems to simulate and characterize flow rates and DOC transport during and succeeding storm events where field measurements are often limited.

  1. Assessment of the Mutagenicity of Sediments from Yangtze River Estuary Using Salmonella Typhimurium/Microsome Assay

    PubMed Central

    Liu, Li; Chen, Ling; Floehr, Tilman; Xiao, Hongxia; Bluhm, Kerstin; Hollert, Henner; Wu, Lingling

    2015-01-01

    Sediments in estuaries are of important environmental concern because they may act as pollution sinks and sources to the overlying water body. These sediments can be accumulated by benthic organisms. This study assessed the mutagenic potential of sediment extracts from the Yangtze River estuary by using the Ames fluctuation assay with the Salmonella typhimurium his (−) strain TA98 (frameshift mutagen indicator) and TA100 (baseshift mutagen indicator). Most of the sediment samples were mutagenic to the strain TA98, regardless of the presence or absence of exogenous metabolic activation (S9 induction by β-naphthoflavone/phenobarbital). However, none of the samples were mutagenic to the strain TA100. Thus, the mutagenicity pattern was mainly frameshift mutation, and the responsible toxicants were both direct (without S9 mix) and indirect (with S9 mix) mutagens. The mutagenicity of the sediment extracts increased when S9 was added. Chemical analysis showed a poor correlation between the content of priority polycyclic aromatic hydrocarbons and the detected mutagenicity in each sample. The concept of effect-directed analysis was used to analyze possible compounds responsible for the detected mutagenic effects. With regard to the mutagenicity of sediment fractions, non-polar compounds as well as weakly and moderately polar compounds played a main role. Further investigations should be conducted to identify the responsible components. PMID:26606056

  2. Geomorphological characteristics and variability of Holocene mass-transport complexes, St. Lawrence River Estuary, Canada

    NASA Astrophysics Data System (ADS)

    Pinet, Nicolas; Brake, Virginia; Campbell, Calvin; Duchesne, Mathieu J.

    2015-01-01

    Recently acquired multibeam bathymetry data are used to investigate seafloor instability features along a 310 km-long segment of the St. Lawrence River Estuary. The analysis of this dataset indicates that submarine slides occur over a much larger area than previously recognized and that Holocene sediments are reworked by mass-transport along significant portions of both the northwest and southeast margins of the Laurentian Channel. In the surveyed area, 96 individual mass-transport complexes (MTCs) were identified representing 13% of the seabed. MTCs vary in area from less than 1 km2 to more than 40 km2 and exhibit various geomorphological signatures. Qualitative observation reveals an apparent disparity between MTCs that remain coherent and those that disintegrate during downslope transport evolving into a blocky morphological signature. For all MTCs, morphological parameters have been measured (area, length, and height) or calculated (slope and roughness). This quantitative analysis provides a unique opportunity to study these parameters in a statistically significant and homogeneous dataset located in a relatively small area that experienced a similar Quaternary history. In many cases, mass transport events appear to initiate in the vicinity of steep bedrock walls located along some segments of the estuary. The timing of mass-transport events was not constrained during this study. However, the fact that the region hosts the Charlevoix seismic zone, the most tectonically active area in eastern Canada, strongly suggests that earthquakes acted as a trigger for submarine landsliding.

  3. Temporal trends of PCBs in sediments and striped bass from the Hudson River and estuary

    SciTech Connect

    Chillrud, S.N.; Simpson, H.J.; Bopp, R.F.; Sloan, R.N.

    1995-12-31

    Chlorinated hydrocarbon chronologies of fine-grained sediments in NY Harbor indicate that decreasing concentration trends of total polychlorinated biphenyls which began in the late 1960s and early 1970s continued through the late 1980s. 1994 core top samples are currently being analyzed. This recent decline in total-PCB levels in NY harbor sediments can be described by a two component exponential function with separate terms representing the two primary sources of PCBs to this area. According to this function, transport from the Upper Hudson River dominated total PCB loading to NY Harbor in the 1970s, while local urban influxes were more important by the mid 1980s. The rate of decline in the geometric mean of lipid-based total-PCB concentrations in striped bass collected throughout the lower Hudson estuary between 1978 and 1990 is very similar to the trends observed in NY Harbor sediments. This similarity is consistent with the hypotheses that striped bass caught in the estuary obtain a significant fraction of their PCB burden in the NY Harbor area and contiguous estuarine waters and indicates that analyses of a relatively small number of dated sediment samples can provide an excellent indication of likely future trends of PCB levels in striped bass populations.

  4. Antibiotic-resistant bacteria in the Hudson River Estuary linked to wet weather sewage contamination.

    PubMed

    Young, Suzanne; Juhl, Andrew; O'Mullan, Gregory D

    2013-06-01

    Heterotrophic bacteria resistant to tetracycline and ampicillin were assessed in waterways of the New York City metropolitan area using culture-dependent approaches and 16S rRNA gene sequence analysis of resultant isolates. Resistant microbes were detected at all 10 sampling sites in monthly research cruises on the lower Hudson River Estuary (HRE), with highest concentrations detected at nearshore sites. Higher frequency sampling was conducted in Flushing Bay, to enumerate resistant microbes under both dry and wet weather conditions. Concentrations of ampicillin- and tetracycline-resistant bacteria, in paired samples, were positively correlated with one another and increased following precipitation. Counts of the fecal indicator, Enterococcus, were positively correlated with levels of resistant bacteria, suggesting a shared sewage-associated source. Analysis of 16S rRNA from isolates identified a phylogenetically diverse group of resistant bacteria, including genera containing opportunistic pathogens. The occurrence of Enterobacteriaceae, a family of enteric bacteria, was found to be significantly higher in resistant isolates compared to total heterotrophic bacteria and increased following precipitation. This study is the first to document the widespread distribution of antibiotic-resistant bacteria in the HRE and to demonstrate clearly a link between the abundance of antibiotic-resistant bacteria and levels of sewage-associated bacteria in an estuary. PMID:23708577

  5. Metagenomic Analysis of Virioplankton of the Subtropical Jiulong River Estuary, China

    PubMed Central

    Cai, Lanlan; Zhang, Rui; He, Ying; Feng, Xiaoyuan; Jiao, Nianzhi

    2016-01-01

    Viruses are the most abundant biological entities in the oceans, and encompass a significant reservoir of genetic diversity. However, little is known about their biodiversity in estuary environments, which represent a highly dynamic and potentially more diverse habitat. Here, we report a metagenomic analysis of the dsDNA viral community from the Jiulong River Estuary (JRE), China, and provide a comparative analysis with other closely related environments. The results showed that the majority of JRE virome did not show any significant similarity to the database. For the major viral group (Caudovirales) detected in the sample, Podoviridae (44.88%) were the most abundant family, followed by Siphoviridae (32.98%) and Myoviridae (17.32%). The two most abundant viruses identified in the virome were phages HTVC010P and HMO-2011, which infect bacteria belonging to marine SAR11 and SAR116 clades, respectively. Two contigs larger than 20 kb, which show similar overall genome architectures to Celeribacter phage P12053L and Thalosomonas phage BA3, respectively, were generated during assembly. Comparative analysis showed that the JRE virome was more similar to marine viromes than to freshwater viromes, and shared a relative coarse-grain genetic overlap (averaging 14.14% ± 1.68%) with other coastal viromes. Our study indicated that the diversity and community structure of the virioplankton found in JRE were mainly affected by marine waters, with less influence from freshwater discharge. PMID:26848678

  6. Species composition and gear characteristics of the Macrobrachium fishery of the Cross River Estuary, Nigeria

    NASA Astrophysics Data System (ADS)

    Nwosu, Francis M.

    2010-03-01

    The Cross River Estuary, Nigeria, is an important shrimping area for artisanal fishermen of the coastal communities. The multi-species Macrobrachium fishery is exploited with three main gears, namely beach seine, push net and trap. Studies on species composition of this fishery recorded thirteen shrimp species, one swimming crab ( Callinectes amnicola) and two fish species ( Eleotris sp. and Pellonula leonensis). The shrimp species identified included Macrobrachium macrobrachion (83.39% and 55.69% by number and weight, respectively), M. vollenhovenii (9.66% and 37.18%), M. equidens (3.8% and 2.87%), juveniles-sub-adults of Penaeus notialis (1.11% and 1.3%), M. dux, M. felicinum, Palaemonetes africanus, Palaemon maculatus, Palaemon elegans, Desmocaris sp., Leander sp., Nematopalaemon hastatus and Alpheus pontederiae. While the selectivity index for trap was 0.25, beach seine and push net had a lower index of 0.063. The results present the first comprehensive and representative report for the Estuary shrimp fishery and will assist in the management of the biodiversity of this ecosystem.

  7. Nitrogen loading sources and eutrophication of the Neuse River estuary, North Carolina: Direct and indirect roles of atmospheric deposition

    SciTech Connect

    Paerl, H.W.; Mallin, M.A.; Donahue, C.A.; Go, M.; Peierls, B.L.

    1995-01-01

    A multi-year (1990-1993) field survey and in situ bioassay study was undertaken to examine trophic and biogeochemical impacts of nutrient loading events at 3 representative oligohaline and mesohaline locations in the Neuse River Estuary North Carolina. Additional data were evaluated from an earlier study (1987-1990) at a mesohaline location. Previous studies showed the estuary as being nitrogen-limited throughout much of th year. In addition there is evidence and concern that recent increases in nitrogen loading have led to spatial and temporal expansion of phytoplankton blooms, indicating accelerating eutrophication. Accordingly, we examined the roles of significant nitrogen (N) inputs on the eutrophication process.

  8. Trace metals in the Columbia River Estuary following the 18 May 1980 eruption of Mount St. Helens

    SciTech Connect

    Riedel, G.F.; Wilson, S.L.; Holton, R.L.

    1984-10-01

    Dissolved and suspended concentrations of cadmium, copper, iron, manganese, nickel, lead, and zinc were measured in the Columbia River Estuary following the 18 May 1980 eruption of Mount St. Helens. Soluble concentrations of these trace elements were not substantially elevated by the influx of volcanic ash and mud into the estuary during this period, except for somewhat higher than usual concentrations of manganese and copper. A laboratory experiment indicates that manganese leached from volcanic debris in fresh water and in the transition from fresh to slightly saline water probably caused the elevated Mn leaching from the material into fresh water.

  9. A River Runs through It: A School on the Edge of the Columbia River Estuary Combines Science and Stewardship Right in Its Own Backyard.

    ERIC Educational Resources Information Center

    Sherman, Lee

    2002-01-01

    The estuary at the mouth of the Columbia River in Wahkiakum County Washington) provides a natural laboratory for experiential learning. Wahkiakum High School students participate in interdisciplinary projects that have included habitat restoration, a salmon hatchery, stream restoration, tree planting, and recreating the final leg of the Lewis and…

  10. Conservation paleobiology in near time: Isotopic estimates for restoration flows to the estuary of the Colorado River, Mexico

    NASA Astrophysics Data System (ADS)

    Flessa, Karl; Dettman, David; Cintra-Buenrostro, Carlos; Rowell, Kirsten

    2016-04-01

    In most years since 1960, the Colorado River has not reached the sea. Upstream dams and diversions in the U.S.A. and Mexico have diverted the river's water for agricultural and municipal use. The river's estuary in the upper Gulf of California, in Mexico, once supported very large populations of Mulinia coloradoensis, a trophically important bivalve mollusk, and Totoaba macdonaldi, a now-endangered scianid fish,. Because Colorado River water is isotopically distinct from Gulf of California seawater, we used the δ18O composition of the pre-dam bivalve shells and fish otoliths to estimate past salinities and river flows. We estimate that five to ten percent of the river's annual flow would be needed to restore M. coloradoensis habitat in the river's mouth and to restore the nursery grounds of T. macdonaldi. The dead can speak to the living.

  11. Establishment Patterns of Non-native Fishes: Lessons from the Duluth-Superior Harbor and Lower St. Louis River, an Invasion-prone Great Lakes Freshwater Estuary

    EPA Science Inventory

    The St. Louis River freshwater estuary which drains into western Lake Superior and includes the Duluth-Superior (MN-WI) harbor, has a long history of non-native fish introductions. From 1985 to 2002, seven new fishes were identified in the estuary, an unprecedented rate of non-n...

  12. Amino acids in the Pearl River Estuary and adjacent waters: origins, transformation and degradation

    NASA Astrophysics Data System (ADS)

    Chen, Jianfang; Li, Yan; Yin, Kedong; Jin, Haiyan

    2004-10-01

    Two cruises were conducted in the Pearl River Estuary (PRE) and adjacent coastal waters during July 1999 and 2000 to investigate spatial variation, transformation and degradation of amino acids (AAs). Salinity, suspended sediments (SS), chl a, nutrients, dissolved organic carbon, particulate organic carbon, AAs, and hexosamines were measured and analyzed. Concentrations of particulate hydrolysable AAs (PHAAs), dissolved combined AAs and dissolved free AAs ranged from 0.41 to 12.6 μmol L-1, 1.1 to 4.0 μmol L-1 and 0.15 to 1.10 μmol L-1, respectively. AAs concentrations were low in waters of salinity <10, increased to the maximum in the estuarine and coastal plumes (salinity =10-25) and decreased beyond the coastal plume. There was a region where PHAAs were maximum, which coincided with the region of the chl a maximum and depletion of dissolved inorganic phosphorus in the coastal plume south of Hong Kong. This indicates that most of the AAs in estuarine and coastal waters were produced through phytoplankton production and AAs might be a temporary sink for inorganic nitrogen. The ratios of AAs/HAs and glucosamine/galactosamine (Glc-NH2/Gal-NH2) were on average, 26.0 and 3.8, respectively, in biogenic particulate matter (chl a >5 μg L-1 and SS<10 mg L-1), decreased in turbid particles (SS>20 mg L-1) and reached the lowest values of 5.8 and 1.4 in sediments. In particular, the ratios of AAs/HAs, Glc-NH2/Gal-NH2 were low in the upper or northwest side of the estuary where turbidity was high. This indicated that these AAs were "old", likely due to resuspension of refractory organic matter from sediments or zooplankton grazing modification and bacterial reworking as the salt wedge advanced upstream near the bottom. Apparently, the dynamics of AAs in the PRE appeared to be governed by biological production processes and estuarine circulation in the estuary. As the chl a maximum developed downstream in the estuarine and coastal plume and the salt wedge moved upstream at

  13. Aquatic metabolism response to the hydrologic alteration in the Yellow River estuary, China

    NASA Astrophysics Data System (ADS)

    Shen, Xiaomei; Sun, Tao; Liu, Fangfang; Xu, Jing; Pang, Aiping

    2015-06-01

    Successful artificial hydrologic regulation and environmental flow assessments for the ecosystem protection require an accurate understanding of the linkages between flow events and biotic responses. To explore an ecosystem's functional responses to hydrologic alterations, we analysed spatial and temporal variations in aquatic metabolism and the main factors influenced by artificial hydrologic alterations based on the data collected from 2009 to 2012 in the Yellow River estuary, China. Gross primary production (GPP) ranged from 0.002 to 8.488 mg O2 L-1 d-1. Ecosystem respiration (ER) ranged from 0.382 to 8.968 mg O2 L-1 d-1. Net ecosystem production (NEP) ranged from -5.792 to 7.293 mg O2 L-1 d-1 and the mean of NEP was -0.506 mg O2 L-1 d-1, which means that the trophic status of entire estuary was near to balance. The results showed that seasonal variations in the aquatic metabolism are influenced by the hydrologic alteration in the estuary. High water temperature and solar radiation in summer are associated with low turbidity and consequently high rates of GPP and ER, making the estuary net autotrophic in summer, and that also occurred after water-sediment regulation in August. Turbidity and water temperature were identified as two particularly important factors that influenced the variation in the metabolic balance. As a result, metabolism rate did not decrease but increased after the regulation. ER increased significantly in summer and autumn and reached a maximum after the water-sediment regulation in September. GPP and NEP reached a maximum value after the water-sediment regulation in August, and then decreased in autumn. Estuarine ecosystem shifted from net heterotrophy in spring to net autotrophy in summer, and then to net heterotrophy in autumn. Our study indicated that estuarine metabolism may recover to a high level faster in summer than that in other seasons after the short-term water-sediment regulation due to higher water temperature and nutrients.

  14. Surface water characterization of three rivers in the lead/zinc mining region of northeastern Macedonia.

    PubMed

    Ramani, Sheriban; Dragun, Zrinka; Kapetanović, Damir; Kostov, Vasil; Jordanova, Maja; Erk, Marijana; Hajrulai-Musliu, Zehra

    2014-05-01

    Mine waste is recognized as being one of the most serious threats for freshwater ecosystems, and it still represents one of the greatest environmental concerns in Macedonia. The aim of our investigation was to obtain an in-depth understanding of mining influence on freshwater systems from water contamination to effects on aquatic organisms. In this study, we assessed the impact of active lead (Pb)/zinc (Zn) mines Zletovo and Toranica on the water quality of three rivers in northeastern Macedonia (Bregalnica, Zletovska, and Kriva rivers) based on data collected in spring and autumn of 2012. The Bregalnica River, near Shtip, was characterized mainly by weak contamination with arsenic, barium, iron, molybdenum, titanium, uranium, vanadium, nitrate, and phosphate, as well as critical faecal pollution, which alltogether could be connected to agricultural activities; however, an impact of the mines was not observed. Contrary, both the Zletovska and Kriva rivers showed a clear impact of Pb/Zn mines on water quality. In the Zletovska River, increased concentrations of cadmium (Cd), cobalt, cesium, copper, lithium, manganese (Mn), nickel, rubidium, tin, strontium, thallium, Zn, sulphates, and chlorides were found, especially in autumn (e.g., Cd 2.0 μg L(-1); Mn 2.5 mg L(-1); Zn 1.5 mg L(-1)). In the Kriva River, increased Cd (0.270 μg L(-1)) and Pb (1.85 μg L(-1)) concentrations were found only in spring, possibly due to sediment resuspension during greater water discharge. The selected sampling sites on the Bregalnica, Zletovska, and Kriva rivers were confirmed as being appropriate locations for further studies of mining waste's impact on freshwater ecosystems, the first one as a nonimpacted site and the other two as possible areas of increased exposure of aquatic organisms to metals. PMID:24626792

  15. Water quality in the tidal Potomac River and Estuary, hydrologic data report, 1979 water year

    USGS Publications Warehouse

    Blanchard, Stephen F.; Hahl, D.C.

    1981-01-01

    This report contains data on the physical and chemical properties measured during the 1979 water year for the tidal Potomac River and estuary. Data were collected routinely at five major stations and periodically at 14 intervening stations. Each major station represents a cross section through which the transport of selected dissolved and suspended materials will be computed. The intervening stations represent locations at which data were collected for special studies such as: salt water migration, dissolved oxygen dynamics, and other synoptic studies. About 960 samples were analyzed for silicate, Kjeldhal nitrogen, nitrite, phosphorus, chlorophyll and suspended sediment, with additional samples analyzed for organic carbon, calcium, magnesium, sodium, bicarbonate, sulfate, potassium, chloride, fluoride, seston and dissolved solids residue. In addition, about 1400 in-situ measurements of dissolved oxygen, specific conductance, temperature, and Secchi disk transparency are reported. (USGS)

  16. A dinoflagellate Cochlodinium geminatum bloom in the Zhujiang (Pearl) River estuary in autumn 2009

    NASA Astrophysics Data System (ADS)

    Ke, Zhixin; Huang, Liangmin; Tan, Yehui; Song, Xingyu

    2012-05-01

    A severe Cochlodinium geminatum red tide (>300 km2) was observed in the Zhujiang (Pearl) River estuary, South China Sea in autumn 2009. We evaluated the environmental conditions and phytoplankton community structure during the outbreak. The red tide water mass had significantly higher dissolved inorganic phosphate (DIP), ammonia, and temperature, but significantly lower nitrite, nitrate, dissolved inorganic nitrogen (DIN), and DIN/DIP relative to the non-red-tide zones. The phytoplankton assemblage was dominated by dinoflagellates and diatoms during the red tide. C. geminatum was the most abundant species, with a peak density of 4.13×107 cell/L, accounting for >65% of the total phytoplankton density. The DIN/DIP ratio was the most important predictor of species, accounting for 12.45% of the total variation in the phytoplankton community. Heavy phosphorus loading, low precipitation, and severe saline intrusion were likely responsible for the bloom of C. geminatum.

  17. Determination of acoustic attenuation in the Hudson River Estuary by means of ship noise observations.

    PubMed

    Roh, Heui-Seol; Sutin, Alexander; Bunin, Barry

    2008-06-01

    Analysis of sound propagation in a complex urban estuary has application to underwater threat detection systems, underwater communication, and acoustic tomography. One of the most important acoustic parameters, sound attenuation, was analyzed in the Hudson River near Manhattan using measurements of acoustic noise generated by passing ships and recorded by a fixed hydrophone. Analysis of the ship noise level for varying distances allowed estimation of the sound attenuation in the frequency band of 10-80 kHz. The effective attenuation coefficient representing the attenuation loss above cylindrical spreading loss had only slight frequency dependence and can be estimated by the frequency independent value of 0.058 dBm. PMID:18537300

  18. Ecological status and sources of anthropogenic contaminants in mangroves of the Wouri River Estuary (Cameroon).

    PubMed

    Fusi, Marco; Beone, Gian Maria; Suciu, Nicoleta Alina; Sacchi, Angela; Trevisan, Marco; Capri, Ettore; Daffonchio, Daniele; Din, Ndongo; Dahdouh-Guebas, Farid; Cannicci, Stefano

    2016-08-30

    Mangroves are critically threatened by human activities, despite the important ecosystem functions and services they provide. Mangroves in Cameroon represent no exception to the worldwide trend of mangrove destruction, especially around Douala, on the Wouri river estuary. In two sites around Douala, we assessed the presence of sterols, PAHs, PCBs, DEHP, DDT and its metabolite p,p'-DDE and potentially toxic metals in sediment samples. As a proxy of ecological quality, we measured the diversity and abundance of macrobenthos assemblages. We detected p,p'-DDE contamination, with concentrations higher than 3μgkg(-1) in 16 out of 26 samples which were attributed to recent widespread use of DDT. The detection of sterols revealed faecal contamination. Significant sensitivity of the macrobenthos to contaminants was revealed, with possible implications on the overall mangrove vulnerability to climate change and on the provision of ecosystem services to local populations. PMID:27394634

  19. /sup 239/ /sup 240/Pu and /sup 238/Pu in sediments of the Hudson River estuary

    SciTech Connect

    Linsalata, P.; Wrenn, M.E.; Cohen, N.; Singh, N.P.

    1980-12-01

    Plutonium-239,240 and plutonium-238 were determined in 59 Hudson River sediment dredge samples collected during 1973-77 in the vicinity of the Indian Point Nuclear Power Station. Acid leaching followed by solvent extraction, electrodeposition, and alpha-spectrometry were used to extract, purify, and quantitate plutonium isotopes present in these samples. Annual median plutonium-238/plutonium-239,240 isotopic activity ratios in surficial sediments were 0.032 (1973-74), 0.035 (1975), 0.042 (1976), and 0.040 (1977). The source of these nuclides in the estuary was identified by analysis of the sample isotopic activity ratios. On the basis of the sampling regimen and the methods used, it is concluded that no input, other than that of fallout, has contributed significantly to the plutonium burden in Hudson sediments. (1 map, 9 references, 9 tables)

  20. Assessment of essential elements and heavy metals content on Mytilus galloprovincialis from river Tagus estuary.

    PubMed

    Santos, I; Diniz, M S; Carvalho, M L; Santos, J P

    2014-06-01

    Trace elemental content was analysed in edible tissues of Mytilus galloprovincialis collected in five different sampling areas near the mouth of river Tagus estuary in Lisbon. The concentrations of essential elements (S, K, Ca, Fe, Cu, Zn, As, Br and Sr) were determined by energy-dispersive X-ray fluorescence (EDXRF) spectrometry, while toxic elements (Cr, Cd, Hg, Se and Pb) were measured by inductively coupled plasma-atomic emission spectrometry (ICP-AES). The results show that the essential elements K and S are present at the highest concentrations in all the studied samples reaching 2,920 and 4,520 μg g(-1) (fresh weight), respectively. The highest levels of heavy metals found were in two areas close to the city for Pb and Cd, but below the maximum allowed values. PMID:24763710

  1. Evaluating Cumulative Ecosystem Response to Restoration Projects in the Columbia River Estuary, Annual Report 2007

    SciTech Connect

    Johnson, Gary E.; Diefenderfer, Heida L.; Borde, Amy B.; Dawley, Earl M.; Ebberts, Blaine D.; Putman, Douglas A.; Roegner, G. C.; Russell, Micah; Skalski, John R.; Thom, Ronald M.; Vavrinec, John

    2008-10-01

    The goal of this multi-year study (2004-2010) is to develop a methodology to evaluate the cumulative effects of multiple habitat restoration projects intended to benefit ecosystems supporting juvenile salmonids in the lower Columbia River and estuary. Literature review in 2004 revealed no existing methods for such an evaluation and suggested that cumulative effects could be additive or synergistic. Field research in 2005, 2006, and 2007 involved intensive, comparative studies paired by habitat type (tidal swamp vs. marsh), trajectory (restoration vs. reference site), and restoration action (tide gate vs. culvert vs. dike breach). The field work established two kinds of monitoring indicators for eventual cumulative effects analysis: core and higher-order indicators. Management implications of limitations and applications of site-specific effectiveness monitoring and cumulative effects analysis were identified.

  2. Effects of the sandbar breaching on hydrobiological parameters and zooplankton communities in the Senegal River Estuary (West Africa).

    PubMed

    Champalbert, Gisèle; Pagano, Marc; Arfi, Robert; Chevalier, Cristèle

    2014-05-15

    This study describes the changes in hydrology, zooplankton communities and abundance in the Senegal River Estuary (SRE) before and after the breaching of the sandbar in October 2003. Samples were taken in 2003 at 3 stations located upstream (DI), in mid estuary (HY) and downstream (RM), and in 2005 at the same stations (RM becoming Old River Mouth: ORM), plus the new river mouth (NRM) resulting from the morphological evolution of the SRE. The study showed marked seasonal variations that affected the structure and distribution of zooplankton as well as major changes caused by the sandbar opening: increased marine influence throughout the whole SRE, changes in the horizontal gradients, arrival of euryhaline species and increase in meroplankton, in particular decapod larvae, transformation of the ORM area into a slackwater area with limited exchanges and the highest zooplankton numbers during high waters. PMID:24685450

  3. Temporal and spatial variations in the biogeochemical cycling of cobalt in two urban estuaries: Hudson River Estuary and San Francisco Bay

    NASA Astrophysics Data System (ADS)

    Tovar-Sánchez, Antonio; Sañudo-Wilhelmy, Sergio A.; Flegal, A. Russell

    2004-08-01

    Despite the fact that Co is an essential trace element for the growth of marine phytoplankton, there is very limited information on the cycling of this trace metal in the marine environment. We report here the distribution of dissolved (<0.4 μm) and particulate (>0.4 μm) Co in surface waters of the Hudson River Estuary (HRE) and San Francisco Bay (SFB). Samples were collected during several cruises (from 1990 to 1995 in SFB and from 1995 to 1997 in the HRE) along the whole salinity gradient. Dissolved Co concentrations (mean±1 standard deviation) were nearly identical in magnitude in both estuaries despite differences in climate, hydrography, riverine-flow conditions and land-usage (HRE=0.91±0.61 nM; SFB=1.12±0.69 nM). Dissolved Co levels in each system showed non-conservative distributions when plotted as a function of salinity, with increasing concentrations downstream from the riverine end-members. Desorption from suspended particulates and sewage inputs, therefore, seems to be the major processes responsible for the non-conservative behavior of Co observed. Mass balance estimates also indicated that most of the estuarine Co is exported out of both estuaries, indicating that they and other estuarine systems are principal sources of this essential trace element to the open ocean.

  4. Identification of contaminant trends and data gaps for terrestrial vertebrates residing in northeastern estuaries of the United States

    USGS Publications Warehouse

    Rattner, B.A.; Pearson, J.L.; Golden, N.H.; Erwin, R.M.; Ottinger, M.A.

    1998-01-01

    The Biomonitoring of Environmental Status and Trends (BEST) program of the Department of the Interior is focused to identify and understand effects of contaminant stressors on biological resources under their stewardship. One BEST program activity involves evaluation of retrospective data to assess and predict the condition of biota in Atlantic coast estuaries. A 'Contaminant Exposure and Effects--Terrestrial Vertebrates' database (CEE-TV) has been compiled through computerized literature searches of Fish and Wildlife Reviews, BIOSIS, AGRICOLA, and TOXLINE, review of existing databases (e.g., US EPA Ecological Incident Information System, USGS Diagnostic and Epizootic Databases), and solicitation of unpublished reports from conservation agencies, private groups, and universities. Summary information has been entered into the CEE-TV database, including species, collection date (1965-present), site coordinates, sample matrix, contaminant concentrations, biomarker and bioindicator responses, and reference source, utilizing a 96-field dBase format. Currently, the CEE-TV database contains 3500 georeferenced records representing >200 vertebrate species and > 100,000 individuals residing in estuaries from Maine through Florida. This relational database can be directly queried, imported into the ARC/INFO geographic information system (GIS) to examine spatial tendencies, and used to identify 'hot-spots', generate hypotheses, and focus ecotoxicological assessments. An overview of temporal, phylogenetic, and geographic contaminant exposure and effects information, trends, and data gaps will be presented for terrestrial vertebrates residing in estuaries in the northeast United States.

  5. Isotopic evidence for the turnover of biological reactive nitrogen in the Pearl River Estuary, south China

    NASA Astrophysics Data System (ADS)

    Ye, Feng; Ni, Zhixin; Xie, Luhua; Wei, Gangjian; Jia, Guodong

    2015-04-01

    Nitrate (NO3-) concentrations and the isotopic composition (δ15N and δ18O) of water samples from the Pearl River Estuary (PRE), south China, were measured to constrain N sources and processing in springtime. Nitrate concentrations decreased at higher salinities, and dual isotopic values were correlated with 1/[NO3-], both of which suggest mixing of eutrophic freshwater and oligotrophic seawater. However, δ15N and δ18O values did not closely follow the expected mixing lines. At low salinities (0-3.0), some samples exhibited high δ15N and low δ18O values compared with those of the riverine end-member, indicating that sewage is a significant source of nitrate (up to 19.0% calculated from δ15N). At salinities of >3.0, Δδ15N and Δδ18O values are linearly correlated with lnƒ (the fraction of NO3- remaining in the system), which is attributable to isotopic Rayleigh fractionation during phytoplankton uptake of nitrate. However, the linear relationship between Δδ15N and Δδ18O is different between the west and east PRE, with a slope of 1.18 in the west and 1.59 in the east. This difference most likely resulted from varying degrees of nitrification due to different water velocities and residence times in the two areas. Our data therefore indicate that dual nitrate isotopic signatures are a valuable way to constrain the sources and behavior of nitrate in river-dominated estuaries.

  6. Organochlorine pesticides in the surface water and sediments of the Pearl River Estuary, South China.

    PubMed

    Yu, Mei; Luo, Xiaojun; Chen, Shejun; Mai, Bixian; Zeng, Eddy Y

    2008-01-01

    Samples of surface water, suspended particulate matter (SPM), and surface sediment, collected from the Pear River Estuary, Guangdong Province, China in July of 2002 and April of 2003, were analyzed for hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs) using gas chromatography with electron capture detection. The levels of total HCHs in water varied from 213 to 3,116 pg/L, although in sediments they ranged from 181 to 1,388 pg/g dry weight. The levels of DDTs were in the range of 228 to 3,284 pg/L in water and 57 to 2,244 pg/g dry weight in sediments, respectively. The observed spatial and temporal variability of concentrations of the target compounds in water body could be attributed to the differences of SPM contents in water body and organic carbon contents in SPM between the two sampling periods. Seven of the 10 water samples collected in July of 2002 had the ratio of dichlorodiphenyltrichloroethane/(dichlorobischlorophenylethane + dichlorodiphenyldichloroethylene) (DDT/[DDD + DDE]) higher than one, indicating that there were likely fresh inputs of DDT to the Pearl River Estuary. The significant positive correlations between the organochlorine pesticide concentrations and organic carbon contents in SPM and sediments indicated that organic matter played an important role in controlling the distributions of these pollutants in the marine environment. Varied correlations between the partition coefficients of pollutants and total organic carbon, salinity, and total SPM contents have been observed, which indicated the influences of these factors on controlling the transport and fate of pollutants in the marine environment. PMID:18092858

  7. Time trends of polybrominated diphenyl ethers in sediment cores from the Pearl River Estuary, South China.

    PubMed

    Chen, She-Jun; Luo, Xiao-Jun; Lin, Zhen; Luo, Yong; Li, Ke-Chang; Peng, Xian-Zhi; Mai, Bi-Xian; Ran, Yong; Zeng, Eddy Y

    2007-08-15

    The present study provides information on the time trend of PBDEs in three sediment cores from the Pearl River Estuary (PRE), South China, using 210Pb dating technique. The sigmaPBDEs (except for BDE 209) concentrations in all sediment cores increased gradually from the bottom (mid-1970s) to the middle layer (later 1980s and early 1990s) followed by different temporal trends in different locations to the surface sediments, reflecting the variations in the consumption of commercial penta-BDEs mixture in different regions of the Pearl River Delta. The BDE 209 concentrations remained constant until 1990 and thereafter increased exponentially to the present, with doubling times of 2.6 +/- 0.5-6.4 +/- 1.6 years, suggesting the increasing market demands for deca-BDE mixture after 1990 in China. The inventories of sigmaPBDEs and BDE 209 in sediments of the PRE were 56.0 and 368.2 ng cm(-2), respectively, and the total burden of PBDEs in the PRE were estimated at 8.6 metric tons. The current sigmaPBDEs and BDE 209 fluxes to the PRE were 2.1 and 29.7 ng cm(-2) yr(-1), respectively. The concurrent increase of BDE 209 fluxes and the annual gross industrial output values of electronics manufacturing revealed that the rapid growth of electronics manufacturing in this region since the early 1990s was responsible for the sharp rise of BDE 209 fluxes in the past decade. The PBDE congener compositions of the cores indicated the various input pathways for PBDEs transport to different locations of the estuary. PMID:17874760

  8. Hydrographic Study of a Highly Stratified River Mouth Estuary. Alvarado Coastal Lagoon, México

    NASA Astrophysics Data System (ADS)

    Perales-Valdivia, H.; Sanay, R.

    2014-12-01

    Two 24 hours surveys on high and low river discharge conditions were used to describe the hydrography and the currents at the entrance of Alvarado Coastal Lagoon, México, located at the southwestern coast of the Gulf of México. This study represent the first of this kind in this lagoon. The Alvardo Coastal Lagoon sustains several economical fisheres in the region, including the shrimp fishery. The inlet of the Alvarado Coastal Lagoon is a microtidal rivermouth estuary. In each survey, towed ADCP and hydrographic data were sampled during a diurnal tidal cycle for three across-inlet transects located near the mouth. 12 track repetitions were completed allowing to distinguish the subtidal and tidal signals. In both runoff conditions a salt wedge was present, and showed surface-bottom salinity difference up to 35 psu. During high river discharge condition the salt wedge was present only during flood tide. The thicknesses of the interface, and upper and bottom layers oscillated according the tide. The water surface layer was always toward the ocean. During low river discharge condition the salt wedge was present for the whole tidal cycle. The vertical position of the interface oscillated as the tide did but keeping a constant thickness.

  9. Large-river delta-front estuaries as natural "recorders" of global environmental change.

    PubMed

    Bianchi, Thomas S; Allison, Mead A

    2009-05-19

    Large-river delta-front estuaries (LDE) are important interfaces between continents and the oceans for material fluxes that have a global impact on marine biogeochemistry. In this article, we propose that more emphasis should be placed on LDE in future global climate change research. We will use some of the most anthropogenically altered LDE systems in the world, the Mississippi/Atchafalaya River and the Chinese rivers that enter the Yellow Sea (e.g., Huanghe and Changjiang) as case-studies, to posit that these systems are both "drivers" and "recorders" of natural and anthropogenic environmental change. Specifically, the processes in the LDE can influence ("drive") the flux of particulate and dissolved materials from the continents to the global ocean that can have profound impact on issues such as coastal eutrophication and the development of hypoxic zones. LDE also record in their rapidly accumulating subaerial and subaqueous deltaic sediment deposits environmental changes such as continental-scale trends in climate and land-use in watersheds, frequency and magnitude of cyclonic storms, and sea-level change. The processes that control the transport and transformation of carbon in the active LDE and in the deltaic sediment deposit are also essential to our understanding of carbon sequestration and exchange with the world ocean--an important objective in global change research. U.S. efforts in global change science including the vital role of deltaic systems are emphasized in the North American Carbon Plan (www.carboncyclescience.gov). PMID:19435849

  10. The Caloosahatchee River Estuary: a monitoring partnership between Federal, State, and local governments, 2007-13

    USGS Publications Warehouse

    Patino, Eduardo

    2014-01-01

    From 2007 to 2013, the U.S. Geological Survey (USGS), in cooperation with the Florida Department of Environmental Protection (FDEP) and the South Florida Water Management District (SFWMD), operated a flow and salinity monitoring network at tributaries flowing into and at key locations within the tidal Caloosahatchee River. This network was designed to supplement existing long-term monitoring stations, such as W.P. Franklin Lock, also known as S–79, which are operated by the USGS in cooperation with the U.S. Army Corps of Engineers, Lee County, and the City of Cape Coral. Additionally, a monitoring station was operated on Sanibel Island from 2010 to 2013 as part of the USGS Greater Everglades Priority Ecosystem Science initiative and in partnership with U.S. Fish and Wildlife Service (J.N. Ding Darling National Wildlife Refuge). Moving boat water-quality surveys throughout the tidal Caloosahatchee River and downstream estuaries began in 2011 and are ongoing. Information generated by these monitoring networks has proved valuable to the FDEP for developing total maximum daily load criteria, and to the SFWMD for calibrating and verifying a hydrodynamic model. The information also supports the Caloosahatchee River Watershed Protection Plan.

  11. Modelling of river plume dynamics in Öre estuary (Baltic Sea) with Telemac-3D hydrodynamic model

    NASA Astrophysics Data System (ADS)

    Sokolov, Alexander

    2016-04-01

    The main property of river plumes is their buoyancy, fresh water discharged by rivers is less dense than the receiving, saline waters. To study the processes of plume formation in case of river discharge into a brackish estuary where salinity is low (3.5 - 5 psu) a three dimensional hydrodynamic model was applied to the Öre estuary in the Baltic Sea. This estuary is a small fjord-like bay in the north part of the Baltic Sea. Size of the bay is about 8 by 8 km with maximum depth of 35 metres. River Öre has a small average freshwater discharge of 35 m3/s. But in spring during snowmelt the discharge can be many times higher. For example, in April 2015 the discharge increased from 8 m3/s to 160 m3/s in 18 days. To study river plume dynamics a finite element based three dimensional baroclinic model TELEMAC - 3D is used. The TELEMAC modelling suite is developed by the National Laboratory of Hydraulics and Environment (LNHE) of Electricité de France (EDF). Modelling domain was approximated by an unstructured mesh with element size varies from 50 to 500 m. In vertical direction a sigma-coordinate with 20 layers was used. Open sea boundary conditions were obtained from the Baltic Sea model HIROMB-BOOS using COPERNICUS marine environment monitoring service. Comparison of modelling results with observations obtained by BONUS COCOA project's field campaign in Öre estuary in 2015 shows that the model plausible simulate river plume dynamics. Modelling of age of freshwater is also discussed. This work resulted from the BONUS COCOA project was supported by BONUS (Art 185), funded jointly by the EU and the Swedish Research Council Formas.

  12. Estimating salinity intrusion effects due to climate change on the Lower Savannah River Estuary

    USGS Publications Warehouse

    Conrads, Paul A.; Roehl, Edwin A.; Daamen, Ruby C.; Cook, John B.; Sexton, Charles T.; Tufford, Daniel L.; Carbone, Gregory J.; Dow, Kristin

    2010-01-01

    The ability of water-resource managers to adapt to future climatic change is especially challenging in coastal regions of the world. The East Coast of the United States falls into this category given the high number of people living along the Atlantic seaboard and the added strain on resources as populations continue to increase, particularly in the Southeast. Increased temperatures, changes in regional precipitation regimes, and potential increased sea level may have a great impact on existing hydrological systems in the region. The Savannah River originates at the confluence of the Seneca and Tugaloo Rivers, near Hartwell, Ga., and forms the state boundary between South Carolina and Georgia. The J. Strom Thurmond Dam and Lake, located 238 miles upstream from the Atlantic Ocean, is responsible for most of the flow regulation that affects the Savannah River from Augusta, Ga., to the coast. The Savannah Harbor experiences semi-diurnal tides of two low and two high tides in a 24.8-hour period with pronounced differences in tidal range between neap and spring tides occurring on a 14-day and 28-day lunar cycle. Salinity intrusion results from the interaction of three principal forces - streamflow, mean tidal water levels, and tidal range. To analyze, model, and simulate hydrodynamic behaviors at critical coastal streamgages in the Lower Savannah River Estuary, data-mining techniques were applied to over 15 years of hourly streamflow, coastal water-quality, and water-level data. Artificial neural network (ANN) models were trained to learn the variable interactions that cause salinity intrusions. Streamflow data from the 9,850 square-mile Savannah River Basin were input into the model as time-delayed variables. Tidal inputs to the models were obtained by decomposing tidal water-level data into a “periodic” signal of tidal range and a “chaotic” signal of mean water levels. The ANN models were able to convincingly reproduce historical behaviors and generate

  13. Holocene Sedimentation in the Ångermanälven River Estuary, the northern Baltic Sea

    NASA Astrophysics Data System (ADS)

    Kotilainen, Aarno; Hyttinen, Outi; Obrochta, Stephen; Andrén, Thomas; Ryabchuk, Daria; Snowball, Ian; IODP Expedition 347 Science Party, The

    2015-04-01

    In the IODP Expedition 347 - "Baltic Sea Paleoenvironment" - two sites in the Ångermanälven River estuary were drilled. Sites M0061 and M0062 are located at about 62°47'N, in an area which was deglaciated ca. 10 ka ago. It has long been known that varve deposition is an ongoing process in Ångermanälven estuary, and that it has continued so several thousand years back in time. It has also been shown that a correlation exists between maximum daily discharge and mean varve thickness at least AD 1901-1971 in the Ångermanälven River (Sander et al. 2002). Studying varve thickness and sediment geochemistry potentially yield estimations on past changes in precipitation and sedimentation processes in the estuary. In this presentation, the preliminary results from site M0062 are shown. The core recovery was approximately 36 m and the sediment sequence was divided into two lithological units (Expedition 347 Scientists, 2014). The lowest Unit 2 (17.09-35.9 mbsf) consists of well-sorted sand, deposited by a (glacio)fluvial system. Unit 1 (0-17.09 mbsf) showed transition from glacial lake varves to brackish marine couplets. The uppermost 18 metres were analysed for grain-size and elemental geochemistry every 0.3-0.5 m. From selected intervals, a 1mm-resolution XRF-scanning of the split core surface was done to compare changes in the relative abundance of light elements. Results from Ångermanälven were compared with measurements from glacial varved sediments, retrieved from the eastern Gulf of Finland. This work is also part of "Climate - ice sheet - sea interactions - evolution of the Baltic Sea Basin over the past 60000 years (CISU)" which is a new joint research project with The Academy of Finland and The Russian Foundation for Basic Research. The CISU project is coordinated by Geological Survey of Finland and the other partners are Helsinki University and A.P. Karpinsky Russian Geological Research Institute (VSEGEI), Russia. The project bases on the IODP Expedition

  14. Contribution of the upper river, the estuarine region, and the adjacent sea to the heavy metal pollution in the Yangtze Estuary.

    PubMed

    Yin, Su; Wu, Yuehan; Xu, Wei; Li, Yangyang; Shen, Zhenyao; Feng, Chenghong

    2016-07-01

    To determine whether the discharge control of heavy metals in the Yangtze River basin can significantly change the pollution level in the estuary, this study analyzed the sources (upper river, the estuarine region, and the adjacent sea) of ten heavy metals (As, Cd, Co, Cr, Cu, Hg, Ni, Pb, Sb, and Zn) in dissolved and particulate phases in the surface water of the estuary during wet, normal, and dry seasons. Metal sources inferred from section fluxes agree with those in statistical analysis methods. Heavy metal pollution in the surface water of Yangtze Estuary primarily depends on the sediment suspension and the wastewater discharge from estuary cities. Upper river only constitutes the main source of dissolved heavy metals during the wet season, while the estuarine region and the adjacent sea (especially the former) dominate the dissolved metal pollution in the normal and dry seasons. Particulate metals are mainly derived from sediment suspension in the estuary and the adjacent sea, and the contribution of the upper river can be neglected. Compared with the hydrologic seasons, flood-ebb tides exert a more obvious effect on the water flow directions in the estuary. Sediment suspension, not the upper river, significantly affects the suspended particulate matter concentration in the estuary. PMID:27155472

  15. Flow and transport in the Suwannee River estuary, Florida, 1999-2000: Analysis of data and three-dimensional simulations

    USGS Publications Warehouse

    Bales, Jerad D.; Tomlinson, S.A.; Tillis, Gina

    2006-01-01

    A three-dimensional numerical model was developed to assist in the evaluation of the effects of changes in freshwater flow on the salinity regime of the lower Suwannee River, its estuary, and Suwannee Sound. Hydrodynamic and salt-transport modeling were supported by data from a comprehensive data-collection network operated in the lower Suwannee River during 1998-2000. The study area included all of the downstream-most 12 kilometers of the Suwannee River, Suwannee Sound, and part of the Gulf of Mexico. Development, calibration, and application of the hydrodynamic and salt-transport model were completed by using data primarily collected during October 1999-September 2000.

  16. Circulation and mixing along the North Passage in the Changjiang River estuary, China

    NASA Astrophysics Data System (ADS)

    Pu, Xiang; Shi, John Z.; Hu, Guo-Dong; Xiong, Long-Bing

    2015-08-01

    Simultaneous field observations were made of time series of water level, current velocity, salinity and suspended sediment concentration at ten hydrological gauging stations along the North Passage in the Changjiang River estuary on 17 to 24 February (dry season) and 12 to 18 August 2012 (wet season), respectively. Quantitative analyses of those data are attempted to understand circulation and mixing along the Deepwater Navigational Channel in this estuary. Landward subtidal flow only appears during the neap tide. The maximum bottom landward velocity is in the order of 0.05-0.1 m·s- 1 in the dry season and 0.15-0.2 m·s- 1 in the wet season, respectively. In both dry and wet seasons, calculated mixing parameter (M), which is the ratio of the tidal timescale to the vertical mixing timescale, is below the critical value (1.0) on a neap tide but above it on a spring tide within the middle and lower reaches of the Channel. This suggests that tidal variation of mixing may be able to generate the tidal straining circulation during the periodic stratified spring tide. The interaction between significant river shear flow and longitudinal density gradient, a process termed "river effect" in this study, is revealed as the major reason for seasonal variation of stratification. The competition between tidal stirring, gravitational circulation and river effect could produce an increase in tidal mean value of the potential energy anomaly (ϕ) from neap to spring tides. Tidal mean value of the Simpson number (Si) over a neap tide surpasses the critical value (8.4 × 10- 1) within the middle reach of the Channel, suggesting the occurrence of persistent stratification there. Tidal mean Si over a spring tide is in the order of 8.4 × 10- 1-8.8 × 10- 2 within the middle reach, suggesting the occurrence of strain induced periodic stratification (SIPS). Shear prevails within the pycnocline in the middle and lower reaches of the Channel on a neap tide, with the value of squared shear

  17. Effects of intratidal and tidal range variability on circulation and salinity structure in the Cape Fear River Estuary, North Carolina

    NASA Astrophysics Data System (ADS)

    Becker, May Ling; Luettich, Richard A.; Seim, Harvey

    2009-04-01

    Tidal influences on circulation and the salinity structure are investigated in the largely unstudied Cape Fear River Estuary (CFRE), North Carolina, a partially mixed estuary along the southeast coast of the United States. During two different tidal conditions (high versus low tidal range) and when river flow was low, salinity and velocity data were collected over a semidiurnal tidal cycle in a 2.8 km long transect along the estuary axis. Water level data were recorded nearby. Mechanisms that influence salt transport characteristics are diagnosed from an analysis of the field data. Specifically, we investigated the relationship between tidal range and salinity through comparison of along-channel circulation characteristics, computed salt fluxes, and coefficients of vertical eddy diffusivity (Kz) based on a parameterization and on salt budget analysis. Findings indicate up-estuary tidally driven salt fluxes resulting from oscillatory salt transport are dominant near the pycnocline, while mean advective transport dominates near the bottom during both tidal range periods. Earlier research related to salt transport in estuaries with significant gravitational circulation suggests that up-estuary salt transport increases during low tidal ranges as a result of increased gravitational circulation. In the CFRE, in contrast, net (tidally averaged) near-bottom along-channel velocities are greater during higher tidal range conditions than during lower tidal range conditions. Findings indicate stronger tidal forcing and associated mixing contribute to greater near-bottom salinity gradients and, consequently, increased baroclinic circulation. Lower near-bottom salinities during the higher tidal range period are a result of a combination of increased vertical turbulent salt fluxes near the pycnocline and increased bottom-generated mixing.

  18. Spatial-temporal variations of phosphorus fractions in surface water and suspended particles in the Daliao River Estuary, Northeast China.

    PubMed

    Zhang, Lei; Qin, Yanwen; Han, Chaonan; Cao, Wei; Ma, Yingqun; Shi, Yao; Liu, Zhichao; Yang, Chenchen

    2016-08-01

    The transport and storage of phosphorus in estuary is a complex biogeochemical process as the result of the convergence of fresh and saline water. The objective of the current study is to investigate the spatial-temporal variations of phosphorus fractions in surface water and suspended particles of Daliao River Estuary, China. Samples were collected in August (wet season) and November (dry season), 2013. The results showed that total particulate phosphorus (TPP) in water accounted for more than 50 % of the total phosphorus (TP). Meanwhile, in suspended particles, more than 62 % of particulate phosphorus was in the form of bioavailable phosphorus, including exchangeable phosphorus (Exc-P), extractable organic phosphorus (Exo-P), and iron-bound phosphorus (Fe-P), which meant that the potential impacts of bioavailable phosphorus in suspended particles on estuarine water environment cannot be ignored. There were significantly seasonal variations of phosphorus fractions in the Daliao River Estuary. The concentrations of phosphorus fractions in water in wet season were much lower than that in dry season because of the dilution effect of larger rainfall in wet season. In addition, spatial distribution characteristics of phosphorus fractions were also obvious. Due to terrigenous phosphorus input from the upstream of tidal reach and seawater dilution effect in coastal estuary, total dissolved phosphorus (TDP) concentrations in water gradually decreased from tidal reach to coastal estuary. However, the concentrations of TPP and TP in water and Exo-P in suspended particles presented spatial fluctuation, and these were greatly attributed to sediment re-suspension in coastal estuary. PMID:27155833

  19. Distribution and fate of synthetic musks in the Songhua River, Northeastern China: influence of environmental variables.

    PubMed

    Lu, Binyu; Feng, Yujie; Gao, Peng; Zhang, Zhaohan; Lin, Nan

    2015-06-01

    Contamination levels and spatial and temporal distributions of six typical synthetic musks (SMs) in water and sediment of the Songhua River in Northeastern China were investigated. Experimental data for 72 water and 52 sediment samples collected at 29 sampling sites over 12 months spanning 2011-2012 showed that the Songhua River had been contaminated to different degrees at various sites separately from the river's source. The polycyclic musks 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta-(g)-2-benzopyran (HHCB) (Galaxolide) and 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphthalene (AHTN) (Tonalide) were found most frequently and at the highest levels. Concentrations of HHCB were <2-37 ng/L in water and <0.5-17.5 ng/g dry weight (dw) in sediment. AHTN was <1-8 ng/L in water and <0.5-5.7 ng/g dw in sediment. Statistical relationships between SM concentrations and four environmental variables (temperature, illumination, runoff, and population density) in the Songhua River Basin were formulated. Concentration levels varied proportionately with the size of the city along the river, while the distribution patterns showed clear seasonal variations. HHCB/AHTN ratios mirrored the transfer and transmitting process of SMs. Concentrations of target compounds were correlated with each other, suggesting similar exposure sources. Environmental risk assessment of SMs presented seasonal variations and provided baseline information on SM exposure in the Songhua River Basin. PMID:25874412

  20. Discharge-measurement system using an acoustic Doppler current profiler with applications to large rivers and estuaries

    USGS Publications Warehouse

    Simpson, Michael R.; Oltmann, Richard N.

    1993-01-01

    Discharge measurement of large rivers and estuaries is difficult, time consuming, and sometimes dangerous. Frequently, discharge measurements cannot be made in tide-affected rivers and estuaries using conventional discharge-measurement techniques because of dynamic discharge conditions. The acoustic Doppler discharge-measurement system (ADDMS) was developed by the U.S. Geological Survey using a vessel-mounted acoustic Doppler current profiler coupled with specialized computer software to measure horizontal water velocity at 1-meter vertical intervals in the water column. The system computes discharge from water-and vessel-velocity data supplied by the ADDMS using vector-algebra algorithms included in the discharge-measurement software. With this system, a discharge measurement can be obtained by engaging the computer software and traversing a river or estuary from bank to bank; discharge in parts of the river or estuarine cross sections that cannot be measured because of ADDMS depth limitations are estimated by the system. Comparisons of ADDMS-measured discharges with ultrasonic-velocity-meter-measured discharges, along with error-analysis data, have confirmed that discharges provided by the ADDMS are at least as accurate as those produced using conventional methods. In addition, the advantage of a much shorter measurement time (2 minutes using the ADDMS compared with 1 hour or longer using conventional methods) has enabled use of the ADDMS for several applications where conventional discharge methods could not have been used with the required accuracy because of dynamic discharge conditions.

  1. [Spatial and temporal distribution of organochlorine pesticides (OCPs) in surface water from the Pearl River Artery estuary].

    PubMed

    Yang, Qing-shu; Mai, Bi-xian; Fu, Jia-mo; Sheng, Guo-ying; Wang, Jing-xin

    2004-03-01

    Six water samples were collected, and twenty-one compounds of organochlorine pesticides (OCPs) in surface water from the Pearl River Artery estuary were analyzed quantitatively, based on USEPA 8000 series methods and under quality assurance and quality control (QA/QC). The total (particulate plus dissolved phase) concentration of OCPs in surface water from the Pearl River Artery estuary in both high flow season and low flow season were 9.7 ng/L-26.3 ng/L and 41.7 ng/L-122.5 ng/L respectively. The concentration of total HCHs and total other OCPs was much higher than that of DDTs. The seasonality of the concentration of OCPs was significantly, and the level of OCPs in low flow season was higher than that of OCPs in high flow season. The spatial and temporal distribution of OCPs suggested that there were significant differences of OCPs between the East River (Dongjiang) network and Guangzhou channel and the nonpoint-source pollution of OCPs was found in the Pearl River Artery estuary, particularly in high flow season. PMID:15202254

  2. Delineation of the sources and sinks of heterogeneously distributed methane in the Pearl River and its estuary

    NASA Astrophysics Data System (ADS)

    Wang, J.; Xie, W.; Wei, Y.; Zhang, C.

    2013-12-01

    Methane in low temperature environments is mostly produced by methanogens. Sharp decrease in methane concentration has been observed from freshwater to marine water in coastal regions. The goal of this study was to delineate the sources and sinks of methane from the lower Pearl River (including, North, West, and East segments) and its estuary along a salinity gradient (0.0 % to 3.4%). Methane concentration in lower Pearl River ranged from 50.1 to 10578 nmol L-1 in the winter (average = 565.5 × 1464.9 nmol L-1) and from 38.4 to 974.1 nmol L-1 in the summer (average = 179.6 × 165.7 nmol L-1). In the estuary, however, methane concentration was 5-10 folds lower in winter and 3-8 folds lower in summer. The sea-to-air methane flux was also much higher in the fresh water (3159.6 umol/d.m2) than in the estuary (528.1 umol/d.m2). Abnormally high methane concentrations and methane flux in the East Pearl River appear to be associated with effluents of industrial or municipal wastes. DNA sequencing of the archaeal 16S rRNA gene indicates predominance of methanogens in the freshwater and their disappearance in the estuary. This is supported by the archaeal lipoid analysis, which showed the predominance of archaeol and caldarchaeol that characterize the methanogens. It is unknown, however, how aerobic (bacteria) and anerobic (archaea) methanotrophs may be involved in the oxidation of methane in the estuary environment where methane consumption is apparently occurring.

  3. Great earthquakes and tsunamis of the past 2000 years at the Salmon River estuary, central Oregon coast, USA

    USGS Publications Warehouse

    Nelson, A.R.; Asquith, A.C.; Grant, W.C.

    2004-01-01

    Four buried tidal marsh soils at a protected inlet near the mouth of the Salmon River yield definitive to equivocal evidence for coseismic subsidence and burial by tsunami-deposited sand during great earthquakes at the Cascadia subduction zone. An extensive, landward-tapering sheet of sand overlies a peaty tidal-marsh soil over much of the lower estuary. Limited pollen and macrofossil data suggest that the soil suddenly subsided 0.3-1.0 m shortly before burial. Regional correlation of similar soils at tens of estuaries to the north and south and precise 14C ages from one Salmon River site imply that the youngest soil subsided during the great earthquake of 26 January A.D. 1700. Evidence for sudden subsidence of three older soils during great earthquakes is more equivocal because older-soil stratigraphy can be explained by local hydrographic changes in the estuary. Regional 14C correlation of two of the three older soils with soils at sites that better meet criteria for a great-earthquake origin is consistent with the older soils recording subsidence and tsunamis during at least two great earthquakes. Pollen evidence of sudden coseismic subsidence from the older soils is inconclusive, probably because the amount of subsidence was small (<0.5 m). The shallow depths of the older soils yield rates of relative sea-level rise substantially less than rates previously calculated for Oregon estuaries.

  4. Application of cluster analysis to the geochemistry zonation of the estuary waters in the Tinto and Odiel rivers (Huelva, Spain).

    PubMed

    Grande, José Antonio; Borrego, José; de la Torre, Maria Luisa; Sáinz, A

    2003-06-01

    The combination of acid water from mines, industrial effluents and sea water plays a determining role in the evolutionary process of the chemical makeup of the water in the estuary of the Tinto and Odiel rivers. This estuary is in the southwest of the Iberian Peninsula and is one of the estuarine systems on the northwest coast of the Gulf of Cádiz. From the statistical treatment of data obtained by analyzing samples of water from this system, which is affected by industrial and mining pollution processes, we can see how the sampling points studied form two large groups depending on whether they receive tidal or fluvial influences. Fluvial input contributes acid water with high concentrations of heavy metal, whereas industrial effluents are responsible for the presence of phosphates, silica and other nutrients. The estuarine system of the Tinto and Odiel Rivers can be divided into three areas--the Tinto estuary, the Odiel estuary and the area of confluence--based on the physical--chemical characteristics of the water. PMID:12901168

  5. Shallow Sediment Trace Metal Concentrations and Short-Term Accumulation Rates in the Neponset River Estuary, Massachusetts, USA

    NASA Astrophysics Data System (ADS)

    Spencer, J. R.; Zhu, J.; Olsen, C. R.

    2010-12-01

    The Neponset River estuary is a small estuary that drains into the Boston Harbor on the east coast of the United States. It is also a highly urbanized estuary and has a long history of urban development over 450 years. In July 2006, six sediment cores were collected in the Neponset River estuary to examine particle dynamics and sediment accumulation via radionuclide (Beryllium-7) dating, and to determine sediment metal concentrations (As, Cu, Pb, and Zn) via ED-XRF measurements. Measured sediment Be-7 profiles indicate various sedimentation environments, where sediment accumulation, resuspension or redeposition is likely to occur. High metal concentrations were often corresponding to high Be-7 inventories in sediment cores. Possible sources of trace metal contaminants in the water column include: storm water run-off, Combined Sewer Overflows (CSOs), a well-documented industrial pollution event that occurred upstream in the early to mid twentieth century, and the resuspension of sediment. Existing and future data will provide baseline information for quantifying the effects of the proposed and pending environmental restoration project, which includes the removal of the Baker Dam. The combined pre- and post-Dam removal data may then be used in cost-benefit analyses for other similar estuarine restoration projects.

  6. Effects of Irradiance on Benthic and Water Column Processes in a Gulf of Mexico Estuary: Pensacola Bay, Florida, USA

    EPA Science Inventory

    We examined the effect of light on water column and benthic fluxes in the Pensacola Bay estuary, a river-dominated system in the northeastern Gulf of Mexico. Measurements were made during summer 2003 and 2004 on 16 dates at along depth and salinity gradients. Dissolved oxygen flu...

  7. SOURCES AND TRANSFORMATIONS OF NITROGEN, CARBON, AND PHOSPHORUS IN THE POTOMAC RIVER ESTUARY

    NASA Astrophysics Data System (ADS)

    Pennino, M. J.; Kaushal, S.

    2009-12-01

    downstream. Ecological stoichiometric ratios along the river indicate increases in C/N ratios downstream, but no corresponding trend with C/P ratios. The N/P ratios increased directly below the treatment plant and then decreased gradually downstream. The C/N/P ratios remained level until the last two sampling stations within 20 miles of the Chesapeake Bay, where there is a large increase. Despite large inputs, there may be large variations in sources and ecological stoichiometry along rivers and estuaries, and knowledge of these transformations will be important in predicting changes in the amounts, forms, and stoichiometry of nutrient loads to coastal waters.

  8. Soil Phosphorus Forms and Profile Distributions in the Tidal River Network Region in the Yellow River Delta Estuary

    PubMed Central

    Yu, Junbao; Qu, Fanzhu; Wu, Huifeng; Meng, Ling; Du, Siyao; Xie, Baohua

    2014-01-01

    Modified Hedley fraction method was used to study the forms and profile distribution in the tidal river network region subjected to rapid deposition and hydrologic disturbance in the Yellow River Delta (YRD) estuary, eastern China. The results showed that the total P (Pt) ranged from 612.1 to 657.8 mg kg−1. Dilute HCl extractable inorganic P (Pi) was the predominant form in all profiles, both as absolute values and as a percentage of total extracted Pi. The NaOH extractable organic P (Po) was the predominant form of total extracted Po, while Bicarb-Pi and C.HCl-Po were the lowest fractions of total extracted Pi and Po in all the P forms. The Resin-P concentrations were high in the top soil layer and decreased with depth. The Pearson correlation matrix indicated that Resin-P, Bicarb-Pi, NaOH-Pi, and C.HCl-Pi were strongly positively correlated with salinity, TOC, Ca, Al, and Fe but negatively correlated with pH. The significant correlation of any studied form of organic P (Bicarb-Po, NaOH-Po, and C.HCl-Po) with geochemical properties were not observed in the study. Duncan multiple-range test indicated that the P forms and distribution heterogeneity in the profiles could be attributed to the influences of vegetation cover and hydrologic disturbance. PMID:24971393

  9. Hydrologic data summary for the St. Lucie River Estuary, Martin and St. Lucie Counties, Florida, 1998-2001

    USGS Publications Warehouse

    Byrne, Michael J.; Patino, Eduardo

    2004-01-01

    A hydrologic analysis was made at three canal sites and four tidal sites along the St. Lucie River Estuary in southeastern Florida from 1998 to 2001. The data included for analysis are stage, 15-minute flow, salinity, water temperature, turbidity, and suspended-solids concentration. During the period of record, the estuary experienced a drought, major storm events, and high-water discharge from Lake Okeechobee. Flow mainly occurred through the South Fork of the St. Lucie River; however, when flow increased through control structures along the C-23 and C-24 Canals, the North Fork was a larger than usual contributor of total freshwater inflow to the estuary. At one tidal site (Steele Point), the majority of flow was southward toward the St. Lucie Inlet; at a second tidal site (Indian River Bridge), the majority of flow was northward into the Indian River Lagoon. Large-volume stormwater discharge events greatly affected the St. Lucie River Estuary. Increased discharge typically was accompanied by salinity decreases that resulted in water becoming and remaining fresh throughout the estuary until the discharge events ended. Salinity in the estuary usually returned to prestorm levels within a few days after the events. Turbidity decreased and salinity began to increase almost immediately when the gates at the control structures closed. Salinity ranged from less than 1 to greater than 35 parts per thousand during the period of record (1998-2001), and typically varied by several parts per thousand during a tidal cycle. Suspended-solids concentrations were observed at one canal site (S-80) and two tidal sites (Speedy Point and Steele Point) during a discharge event in April and May 2000. Results suggest that most deposition of suspended-solids concentration occurs between S-80 and Speedy Point. The turbidity data collected also support this interpretation. The ratio of inorganic to organic suspended-solids concentration observed at S-80, Speedy Point, and Steele Point

  10. Phytoplankton assemblage of Yangtze River Estuary and the adjacent east China sea in summer, 2004

    NASA Astrophysics Data System (ADS)

    Luan, Qingshan; Sun, Jun; Shen, Zhiliang; Song, Shuqun; Wang, Min

    2006-04-01

    A cruise was conducted from late August to early September 2004 with the intention of obtaining an interdisciplinary understanding of the Yangtze River Estuary including the biological, chemical and physical subjects. Water sample analysis indicated that total phytoplankton species richness was 137. Of them 81 were found in Bacillariophyta and 48 in Pyrrophyta, accounting for 59.1% and 35.0% respectively. The average cell abundance of surface water samples was 8.8×104 cells L-1, with the maximum, 102.9×104 cells L-1, encountered in the area (31.75°N, 122.33°E) and the minimum, 0.2×104 cells L-1, in (30.75°N, 122.17°E). The dominant species at most stations were Skeletonema costatum and Proboscia alata f. gracillima with the dominance of 0.35 and 0.27. Vertical distribution analysis indicated that obvious stratification of cell abundance and dominant species was found in the representative stations of 5, 18 and 33. Shannon-Wiener index and evenness of phytoplankton assemblage presented negative correlation with the cell abundance, with the optimum appearing in (30.75°N, 122.67°E). According to the PCA analysis of the environmental variables, elevated nutrients of nitrate, silicate and phosphate through river discharge were mainly responsible for the phytoplankton bloom in this area.

  11. Impact of river discharge on phytoplankton bloom dynamics in eutrophic estuaries: A model study

    NASA Astrophysics Data System (ADS)

    Liu, Bo; de Swart, Huib E.

    2015-12-01

    Field observations in estuaries reveal that phytoplankton blooms are strongly affected by advection processes related to river flow. To gain quantitative insight into this dependence, experiments were performed with a new idealised model that couples physical and biological processes. Advection of phytoplankton and nutrient by subtidal flow was explicitly accounted for, as well as longitudinal and vertical mixing processes. Results show that the idealised model is capable of reproducing the observed bloom. The specific spatial distribution of phytoplankton population emerges because the latter is suppressed in the upper reach by the advection processes, and the growth is limited in the lower reach by low nutrient concentrations. A sensitivity study of model results to different river discharges reveals the presence of three regimes. In the low discharge regime, blooms form because growth is faster than decay due to advection processes. In the high discharge regime, the situation is opposite and no blooms form. If time scales of growth and advection are comparable (in moderate discharge regime), phytoplankton population increases significantly slower compared to the low discharge regime. Results of additional model runs, in which water depth and the e-folding length scale of estuarine width convergence were varied, revealed that the three regimes occur in all these cases.

  12. Time series modeling and prediction of salinity in the Caloosahatchee River Estuary

    NASA Astrophysics Data System (ADS)

    Qiu, Chelsea; Wan, Yongshan

    2013-09-01

    Complex three-dimensional (3-D) numerical models are often used for simulation and forecasting of salinity for estuarine water resources management. However, the effort which goes into these models is significant, partly due to the difficulty associated with model development and the prolonged computation time required for model runs. Modern water resources management sometimes requires a quick turnaround time for long-term simulations or short-term forecasts of estuarine salinity conditions. This paper presents an innovative approach for the development of an alternative salinity model based on time series analyses of salinity data. The structure of the model consists of an autoregressive term representing the system persistence and an exogenous term accounting for physical drivers including freshwater inflow, rainfall, and tidal water surface elevation that cause salinity to vary. An analogy to 1-D physical models reveals that major physical processes of salt transport are implicitly embedded in the time series model. Model calibration and validation using up to 20 years of measured data collected in the Caloosahatchee River Estuary, Florida indicate that the time series model offers comparable or superior performance compared with its 3-D counterpart. This model has been used as a tool for water resources management projects relating to ecosystem restoration and water control in south Florida. A special case of model application is included to demonstrate how the model has been used for salinity forecasting to support weekly operation of water control infrastructure and water resources management decision making. Similar modeling tools can be developed using this approach for other estuaries.

  13. Herbivorous and microbial grazing pathways of metazooplankton in the Senegal River Estuary (West Africa)

    NASA Astrophysics Data System (ADS)

    Pagano, Marc; Champalbert, Gisèle; Aka, Maryse; Kouassi, Ernest; Arfi, Robert; Got, Patrice; Troussellier, Marc; N'Dour, E. H.; Corbin, Daniel; Bouvy, Marc

    2006-04-01

    The trophic relationships between metazooplankton and natural particles were studied in May 2002 in the Senegal River Estuary (16°N, 16°W) in low water conditions (dry season). Environmental factors, micro-organism and metazooplankton were analyzed through sampling at a fixed station. Gut fluorescence measurements of and field experiments on zooplankton metabolism were also performed. Chlorophyll a concentrations ranged from 6.5 to 10.2 μg l -1. The phytoplankton was dominated by picoplanktonic cells (83-94% of total numbers). The particulate organic carbon (1.2-2.7 mg l -1) originated for a large amount from organic detritus (20-70%). The zooplankton biomass was dominated by Cirripedia larvae and calanoid copepods ( Acartia clausi, Temora stylifera and Paracalanus spp.). These taxa showed diel vertical migrations and maximal gut fluorescence at night, independently of tidal effects. Metabolic budgets show that their daily ingestion rates on phytoplankton (27-55% of body carbon weight) were insufficient to balance their respiration needs (40-51% of body carbon) and suggest that a selective feeding upon micro-heterotrophs (Heterotrophic NanoFlagellates, HNF) and/or detritus would be necessary to complete their energetic needs. The daily grazing pressure of metazooplankton represented only 5% of the in situ chlorophyll a and 14% of the primary production, but this pressure was mainly orientated towards nanophytoplankton. The daily recycling of nutrients by the metazooplankton excretion was rather high (83 and 46% of the in situ NH 4-N and PO 4-P concentrations, respectively). Therefore, the impact of metazooplankton on phytoplankton through top-down (grazing) and bottom-up (nutrient recycling) processes seemed substantial in this tropical estuary.

  14. Distribution patterns of phytoplankton in the Changjiang River estuary and adjacent waters in spring 2009

    NASA Astrophysics Data System (ADS)

    Kong, Fanzhou; Xu, Zijun; Yu, Rencheng; Yuan, Yongquan; Zhou, Mingjiang

    2016-09-01

    The Changjiang River estuary and adjacent waters are one of the most notable regions for red tides/harmful algal blooms in China's coastal waters. In this study, phytoplankton samples were collected and analyzed during the outbreak stage of red tides in May 2009. It was found that dinoflagellates, Prorocentrum donghaiense and Karenia mikimotoi, and diatoms, Skeletonema spp. and Paralia sulcata, were the major taxa dominating the phytoplankton community. Cluster analysis, non-metric multidimensional scaling (NMDS) and analysis of similarities (ANOSIM) was conducted on a data matrix including taxa composition and cell abundance of the phytoplankton samples. The analyses categorized the samples into three groups at a similarity level of 30%. Group I was characterized by estuarine diatoms and distributed mainly in the highly turbid estuarine region. Group II, which was dominated by the diatom Skeletonema spp. and represented the red tide of Skeletonema spp., was situated around Group I in the sea area west of 122°50'E. Group III was characterized by a high proportion of dinoflagellates and was found further offshore compared with Groups I and II. Group III was further divided into two subgroups (III-S1 and III-S2) at a similarity level of 40%. Group III-S1 was characterized by the presence of the benthic diatom P. sulcata, representing phytoplankton samples collected either from the bottom or from the sea area affected by upwelling. Group III-S2 was dominated by dinoflagellates and represented red tides formed by P. donghaiense and K. mikimotoi. A gradual change of red-tide causative species was observed from the estuary to the offshore sea area, from diatoms to armored dinoflagellates and then unarmored dinoflagellates. Environmental factors associated with each group, and thus affecting the distribution of phytoplankton and red tides, are discussed.

  15. Distribution patterns of phytoplankton in the Changjiang River estuary and adjacent waters in spring 2009

    NASA Astrophysics Data System (ADS)

    Kong, Fanzhou; Xu, Zijun; Yu, Rencheng; Yuan, Yongquan; Zhou, Mingjiang

    2016-01-01

    The Changjiang River estuary and adjacent waters are one of the most notable regions for red tides/harmful algal blooms in China's coastal waters. In this study, phytoplankton samples were collected and analyzed during the outbreak stage of red tides in May 2009. It was found that dinoflagellates, Prorocentrum donghaiense and Karenia mikimotoi, and diatoms, Skeletonema spp. and Paralia sulcata, were the major taxa dominating the phytoplankton community. Cluster analysis, non-metric multidimensional scaling (NMDS) and analysis of similarities (ANOSIM) was conducted on a data matrix including taxa composition and cell abundance of the phytoplankton samples. The analyses categorized the samples into three groups at a similarity level of 30%. Group I was characterized by estuarine diatoms and distributed mainly in the highly turbid estuarine region. Group II, which was dominated by the diatom Skeletonema spp. and represented the red tide of Skeletonema spp., was situated around Group I in the sea area west of 122°50'E. Group III was characterized by a high proportion of dinoflagellates and was found further offshore compared with Groups I and II. Group III was further divided into two subgroups (III-S1 and III-S2) at a similarity level of 40%. Group III-S1 was characterized by the presence of the benthic diatom P. sulcata, representing phytoplankton samples collected either from the bottom or from the sea area affected by upwelling. Group III-S2 was dominated by dinoflagellates and represented red tides formed by P. donghaiense and K. mikimotoi. A gradual change of red-tide causative species was observed from the estuary to the offshore sea area, from diatoms to armored dinoflagellates and then unarmored dinoflagellates. Environmental factors associated with each group, and thus affecting the distribution of phytoplankton and red tides, are discussed.

  16. Multi-Scale Action Effectiveness Research in the Lower Columbia River and Estuary, 2011 - FINAL ANNUAL REPORT

    SciTech Connect

    Sather, Nichole K.; Storch, Adam; Johnson, Gary E.; Teel, D. J.; Skalski, J. R.; Bryson, Amanda J.; Kaufmann, Ronald M.; Woodruff, Dana L.; Blaine, Jennifer; Kuligowski, D. R.; Kropp, Roy K.; Dawley, Earl M.

    2012-05-31

    The study reported here was conducted by researchers at Pacific Northwest National Laboratory (PNNL), the Oregon Department of Fish and Wildlife (ODFW), the University of Washington (UW), and the National Marine Fisheries Service (NMFS) for the U.S. Army Corps of Engineers, Portland District (USACE). This research project was initiated in 2007 by the Bonneville Power Administration to investigate critical uncertainties regarding juvenile salmon ecology in shallow tidal freshwater habitats of the lower Columbia River. However, as part of the Washington Memorandum of Agreement, the project was transferred to the USACE in 2010. In transferring from BPA to the USACE, the focus of the tidal freshwater research project shifted from fundamental ecology toward the effectiveness of restoration in the Lower Columbia River and estuary (LCRE). The research is conducted within the Action Agencies Columbia Estuary Ecosystem Restoration Program (CEERP). Data reported herein spans the time period May 2010 to September 2011.

  17. Two Perkinsus spp. infect Crassostrea gasar oysters from cultured and wild populations of the Rio São Francisco estuary, Sergipe, northeastern Brazil.

    PubMed

    da Silva, Patricia Mirella; Scardua, Marcos Paiva; Vianna, Rogério Tubino; Mendonça, Raoani Cruz; Vieira, Cairé Barreto; Dungan, Christopher F; Scott, Gail P; Reece, Kimberly S

    2014-06-01

    Brazilian production of bivalve molluscs is small but expanding, especially in the northeastern region where the native oysters Crassostrea rhizophorae and C. gasar are abundant, and tropical weather promotes their rapid growth. Studies on bivalve pathology are scarce in Brazil, with only a few employing techniques for detecting protozoan pathogens listed by the World Organisation for Animal Health (OIE). In 2008, a Perkinsus sp. was reported for the first time in Brazil, infecting C. rhizophorae oysters from a wild population in Ceará state, NE Brazil. Recently P. marinus was detected in the same oyster species in nearby Paraíba state. These findings highlighted the need to expand knowledge on the presence and impacts of Perkinsus spp. on Brazilian oyster populations. The current investigation evaluated Perkinsus sp. infections among wild and cultured C. gasar mangrove oysters from the estuary of the Rio São Francisco, Sergipe state, NE Brazil. Our results show that Perkinsus sp. infections occurred commonly in oysters of both groups, at prevalences that were frequently higher among cultured oysters. Prevalences varied seasonally, with maximum values during summer (January) of 57% and 80% for wild and cultured oysters respectively, and minimum values during winter (July). Results of DNA sequencing, in situ hybridization assays, and phylogenetic analyses showed dual- and single-pathogen infections by P. marinus and/or P. olseni in the tested oysters. PMID:24780219

  18. Salmon Life Histories, Habitat, and Food Webs in the Columbia River Estuary: An Overview of Research Results, 2002-2006.

    SciTech Connect

    Bottom, Daniel L.; Anderson, Greer; Baptisa, Antonio

    2008-08-01

    From 2002 through 2006 we investigated historical and contemporary variations in juvenile Chinook salmon Oncorhynchus tshawytscha life histories, habitat associations, and food webs in the lower Columbia River estuary (mouth to rkm 101). At near-shore beach-seining sites in the estuary, Chinook salmon occurred during all months of the year, increasing in abundance from January through late spring or early summer and declining rapidly after July. Recently emerged fry dispersed throughout the estuary in early spring, and fry migrants were abundant in the estuary until April or May each year. Each spring, mean salmon size increased from the tidal freshwater zone to the estuary mouth; this trend may reflect estuarine growth and continued entry of smaller individuals from upriver. Most juvenile Chinook salmon in the mainstem estuary fed actively on adult insects and epibenthic amphipods Americorophium spp. Estimated growth rates of juvenile Chinook salmon derived from otolith analysis averaged 0.5 mm d-1, comparable to rates reported for juvenile salmon Oncorhynchus spp. in other Northwest estuaries. Estuarine salmon collections were composed of representatives from a diversity of evolutionarily significant units (ESUs) from the lower and upper Columbia Basin. Genetic stock groups in the estuary exhibited distinct seasonal and temporal abundance patterns, including a consistent peak in the Spring Creek Fall Chinook group in May, followed by a peak in the Western Cascades Fall Chinook group in July. The structure of acanthocephalan parasite assemblages in juvenile Chinook salmon from the tidal freshwater zone exhibited a consistent transition in June. This may have reflected changes in stock composition and associated habitat use and feeding histories. From March through July, subyearling Chinook salmon were among the most abundant species in all wetland habitat types (emergent, forested, and scrub/shrub) surveyed in the lower 100 km of the estuary. Salmon densities

  19. Migratory Behavior and Survival of Juvenile Salmonids in the Lower Columbia River, Estuary, and Plume in 2010

    SciTech Connect

    McMichael, Geoffrey A.; Harnish, Ryan A.; Skalski, John R.; Deters, Katherine A.; Ham, Kenneth D.; Townsend, Richard L.; Titzler, P. Scott; Hughes, Michael S.; Kim, Jin A.; Trott, Donna M.

    2011-09-01

    Uncertainty regarding the migratory behavior and survival of juvenile salmonids passing through the lower Columbia River and estuary after negotiating dams on the Federal Columbia River Power System (FCRPS) prompted the development and application of the Juvenile Salmon Acoustic Telemetry System (JSATS). The JSATS has been used to investigate the survival of juvenile salmonid smolts between Bonneville Dam (river kilometer (rkm) 236) and the mouth of the Columbia River annually since 2004. In 2010, a total of 12,214 juvenile salmonids were implanted with both a passive integrated transponder (PIT) and a JSATS acoustic transmitter. Using detection information from JSATS receiver arrays deployed on dams and in the river, estuary, and plume, the survival probability of yearling Chinook salmon and steelhead smolts tagged at John Day Dam was estimated form multiple reaches between rkm 153 and 8.3 during the spring. During summer, the survival probability of subyearling Chinook salmon was estimated for the same reaches. In addition, the influence of routes of passage (e.g., surface spill, deep spill, turbine, juvenile bypass system) through the lower three dams on the Columbia River (John Day, The Dalles, and Bonneville) on juvenile salmonid smolt survival probability from the dams to rkm 153 and then between rkm 153 and 8.3 was examined to increase understanding of the immediate and latent effects of dam passage on juvenile salmon survival. Similar to previous findings, survival probability was relatively high (>0.95) for most groups of juvenile salmonids from the Bonneville Dam tailrace to about rkm 50. Downstream of rkm 50 the survival probability of all species and run types we examined decreased markedly. Steelhead smolts suffered the highest mortality in this lower portion of the Columbia River estuary, with only an estimated 60% of the tagged fish surviving to the mouth of the river. In contrast, yearling and subyearling Chinook salmon smolts survived to the mouth

  20. Seasonal changes in the intertidal and subtidal macrobenthic invertebrate community structure in Baker Bay, lower Columbia River estuary. Technical memo

    SciTech Connect

    Furota, T.; Emmett, R.L.

    1993-01-01

    Macrobenthic invertebrates and sediments at 1 subtidal and 10 intertidal stations along a transect in Baker Bay of the lower Columbia River estuary were sampled monthly from November 1980 to October 1981. Water column temperatures and salinities were also recorded at the subtidal station. The intertidal community consisted primarily of estuarine species, whereas the subtidal community had additional marine species. Marine species declined in abundance after the interstitial salinity minimum (June), indicating the important role of salinity in determining benthic community structure.

  1. Gametogenic development and spawning of the freshwater clam, Galatea paradoxa (Born 1778) from the Volta River Estuary, Ghana.

    PubMed

    Adjei-Boateng, D; Wilson, J G

    2013-01-01

    The study focused on the reproductive cycle of Galatea paradoxa (Born 1778), a major species for artisanal fishery in the Volta River estuary, Ghana. Condition indices and histological observation of the gonads revealed that G. paradoxa has a single spawning event between July and October. Gametogenesis started in December progressing steadily to a peak in June-July when spawning began until November when individuals were spent. Condition and gonadal indices showed a clear relationship with the gametogenic stages. PMID:25141603

  2. Weight-of-evidence approach in assessment of ecotoxicological risks of acid sulphate soils in the Baltic Sea river estuaries.

    PubMed

    Wallin, Jaana; Karjalainen, Anna K; Schultz, Eija; Järvistö, Johanna; Leppänen, Matti; Vuori, Kari-Matti

    2015-03-01

    Acidity and leaching of metals from acid sulphate soils (ASSs) impair the water quality of receiving surface waters. The largest ASS areas in Europe are found in the coasts of the northern Baltic Sea. We used weight-of-evidence (WoE) approach to assess potential risks in 14 estuary sites affected by ASS in the Gulf of Finland, northern Baltic Sea. The assessment was based on exposure and effect profiles utilizing sediment and water metal concentrations and concurrent pH variation, sediment toxicity tests using the luminescent bacterium Vibrio fischeri and the midge Chironomus riparius, and the ecological status of benthic macroinvertebrate communities. Sediment metal concentrations were compared to national sediment quality criteria/guidelines, and water metal concentrations to environmental quality standards (EQSs). Hazard quotients (HQs) were established for maximum aluminium, cadmium and zinc concentrations at low pH based on applicable US EPA toxicity database. Sediment metal concentrations were clearly elevated in most of the studied estuaries. The EQS of cadmium (0.1 μg/l) was exceeded in 3 estuaries out of 14. The pH-minima were below the national threshold value (5.5) between good and satisfactory water quality in 10 estuaries. V. fischeri bioluminescence indicated toxicity of the sediments but toxic response was not observed in the C. riparius emergence test. Benthic invertebrate communities were deteriorated in 6 out of 14 sites based on the benthic invertebrate quality index. The overall ecotoxicological risk was assessed as low in five, moderate in three and high in five of the estuary sites. The risk assessment utilizing the WoE approach indicated that harmful effects of ASSs are likely to occur in the Baltic Sea river estuaries located at the ASS hotspot area. PMID:25506908

  3. Suspended sediment transport in the Deepwater Navigation Channel, Yangtze River Estuary, China, in the dry season 2009: 2. Numerical simulations

    NASA Astrophysics Data System (ADS)

    Song, Dehai; Wang, Xiao Hua

    2013-10-01

    A three-dimensional wave-current-sediment coupled numerical model with wetting and drying process is developed to understand hydrodynamics and sediment transport dynamics in the Deepwater Navigation Channel (DNC), the North Passage of the Yangtze River Estuary (YRE), China. The model results are in good agreement with observed data, and statistics show good model skill scores and correlation coefficients. The model well reproduces the spring-neap variation between a well-mixed estuary and a highly stratified estuary. Model results indicate that the estuarine gravitational circulation plays the most important role in the estuarine turbidity maximum (ETM) formation in the DNC. The upstream nonlocal sediment intrusion through the spillover mechanism is a major source of sediment trapping in the North Passage after the morphological changes. Numerical studies are conducted to show scenarios in the YRE under the effects of different forcings (river discharges, waves, and winds). Between these study cases, surface-wave-breaking relieves the sediment trapping and bottom-wave-current-interaction aggravates the bed erosion and elevates the SSC in the ETM; the former and the latter have the least and largest influence on the suspended sediment transport in the DNC. The wind effects have a greater influence on sediment trapping than the river discharges, and the steady northwesterly wind condition favors the siltation in the DNC most. The significance of density-driven turbidity current is also assessed, which can enhance the saline-water intrusion and suppress the turbulent mixing in the bottom boundary layer.

  4. Influence of seasonal runoff regulation by the Three Gorges Reservoir on saltwater intrusion in the Changjiang River Estuary

    NASA Astrophysics Data System (ADS)

    Qiu, Cheng; Zhu, Jian-Rong

    2013-12-01

    The Three Gorges Reservoir (TGR) is the largest water conservancy project in the world. It significantly regulates discharge of the Changjiang River on a seasonal scale. It stores water in autumn and drains it during the following dry season. Although the effects of the TGR on various processes in the river, estuary, and adjacent seas have been studied extensively, the TGR's influence on saltwater intrusion around the estuary and its impacts on vital freshwater reservoirs have not been quantitatively evaluated. In this study, we used a well-validated numerical model to simulate the seasonal-scale saltwater intrusion around the Changjiang Estuary under scenarios with and without the TGR regulation. Results showed that during the autumn season, the TGR advanced the timing of saltwater intrusion and slightly increased its intensity. In contrast, as the TGR supplemented river discharge during the dry season, saltwater intrusion around the freshwater reservoirs was significantly suppressed. Moreover, duration of saline water (salinity>0.45, the standard for drinking water) at the Dongfengxisha, Chenhang, and Qingcaosha Reservoirs was shortened by about 16%, 73.1%, and 48%, respectively. The model results showed that overall, operation of the TGR is basically favorable for reducing the burden of freshwater supplement in the high-populated estuarine region.

  5. Polycyclic aromatic hydrocarbons in suspended particulate matter and sediments from the Pearl River Estuary and adjacent coastal areas, China.

    PubMed

    Luo, Xiao-Jun; Chen, She-Jun; Mai, Bi-Xian; Yang, Qing-Shu; Sheng, Guo-Ying; Fu, Jia-Mo

    2006-01-01

    The spatial distribution, composition, and sources of polycyclic aromatic hydrocarbons (PAHs) in sediments and suspended particulate matter (SPM) from the Pearl River Estuary and adjacent coastal areas were examined. Total PAH concentrations varied from 189 to 637 ng/g in sediments and 422 to 1,850 ng/g in SPM. PAHs were dominated by 5,6-ring compounds in sediments and by 2,3-ring compounds in SPM samples. Assessment of PAH sources suggested that biomass and coal combustion is the major PAH source to the outer part of the estuary sediments and that petroleum combustion is the major PAH source to the inner part of estuary sediments. As for SPM samples, PAH isomer pair ratios indicated multiple (petroleum, petroleum combustion, and biomass and coal combustion) PAH sources, and significant temporal variations could exist for the sources of water column PAHs in the study area. The distribution of perylene in SPM samples indicated that the river was the dominant source of perylene in SPM and that perylene could be taken as an index to assess the contribution of river inflow to the total PAHs in SPM samples. The high concentration of perylene in the sediment was indicative of an in situ biogenic origin. PMID:15996803

  6. Light attenuation and submersed macrophyte distribution in the tidal Potomac River and estuary

    USGS Publications Warehouse

    Carter, V.; Rybicki, N.B.

    1990-01-01

    Changing light availability may be responsible for the discontinuous distribution of submersed aquatic macrophytes in the freshwater tidal Potomac River. During the 1985-1986 growing seasons, light attenuation and chlorophyll a and suspended particulate material concentrations were measured in an unvegetated reach (B) and in two adjacent vegetated reaches (A and C). Light attenuation in reach B (the lower, fresh to oligohaline tidal river) was greater than that in reach A (the recently revegetated, upper, freshwater tidal river) in both years. Reach B light attenuation was greater than that in reach C (the vegetated, oligohaline to mesohaline transition zone of the Potomac Estuary) in 1985 and similar to that in reach C in 1986. In reach B, 5% of total below-surface light penetrated only an average of 1.3 m in 1985 and 1.0m in 1986, compared with 1.9 m and 1.4 m in reach A in 1985 and 1986, respectively. Water column chlorophyll a concentration controlled light availability in reaches A and B in 1985, whereas both chlorophyll a and suspended particulate material concentrations were highly correlated with attenuation in both reaches in 1986. Reach C light attenuation was correlated with suspended particulate material in 1986. The relationship between attenuation coefficient and Secchi depth was KPAR=1.38/Secchi depth. The spectral distribution of light at 1 m was shifted toward the red portion of the visible spectrum compared to surface light. Blue light was virtually absent at 1.0 m in reach B during July and August 1986. Tidal range is probably an important factor in determining light availability for submersed macrophyte propagule survival at the sediment-water interface in this shallow turbid system. ?? 1990 Estuarine Research Federation.

  7. Diatoms as Proxies for Abrupt Events in the Hudson River Estuary

    NASA Astrophysics Data System (ADS)

    Skorski, W.; Abbott, D. H.; Recasens, C.; Breger, D. L.

    2014-12-01

    The Hudson River estuary has been subject to many abrupt events throughout its history including hurricanes, droughts and pluvials. Hurricanes in particular are rare, discrete events that if fingerprinted can be used to develop better age models for Hudson River sediments. Proxies use observed physical characteristics or biological assemblages (e.g. diatom and foraminiferal assemblages) as tools to reconstruct past conditions prior to the modern instrumental record. Using a sediment core taken from the Hudson River (CDO2-29A), in New York City, drought and pluvial layers were selected based on Cs-137 dating while hurricane layers were determined from occurrences of tropical to subtropical foraminifera. Contrary to previous studies (Weaver, 1970, Weiss et al, 1978), more than sixty different diatom species have been identified using a scanning electron microscope (SEM). Cosmopolitan, hurricane and drought assemblages have begun to be identified after observing multiple layers (Table 1). Tropical foraminifera dominated by Globigerinoides ruber pink were also found in a hurricane layer that we infer was deposited during Hurricane Belle in 1976. More diatom abundance analyses and cataloged SEM pictures will provide further insight into these proxies. Table 1 Diatom Genera and Species Environment Clarification Cyclotella caspia Planktonic, marine-brackish Cosmopolitan Karayevia clevei Freshwater Cosmopolitan Melosira sp Planktonic, marine Cosmopolitan Thalassiosira sp Marine, brackish Cosmopolitan Staurosirella leptostauron Benthic, freshwater Cosmopolitan Actinoptychus senarius Planktonic or benthic, freshwater to brackish Hurricane and pluvial layers Amphora aff. sp Benthic, marine or freshwater Hurricane layers only Nitzschia sp Benthic, marine or freshwater Hurricane layers only Gomphonema sp Freshwater Hurricane layers only Surirella sp Marine-brackish Drought layer only Triceratium sp Marine Drought layer only Other Genera and species Environment Clarification

  8. Large-river delta-front estuaries as natural “recorders” of global environmental change

    PubMed Central

    Bianchi, Thomas S.; Allison, Mead A.

    2009-01-01

    Large-river delta-front estuaries (LDE) are important interfaces between continents and the oceans for material fluxes that have a global impact on marine biogeochemistry. In this article, we propose that more emphasis should be placed on LDE in future global climate change research. We will use some of the most anthropogenically altered LDE systems in the world, the Mississippi/Atchafalaya River and the Chinese rivers that enter the Yellow Sea (e.g., Huanghe and Changjiang) as case-studies, to posit that these systems are both “drivers” and “recorders” of natural and anthropogenic environmental change. Specifically, the processes in the LDE can influence (“drive”) the flux of particulate and dissolved materials from the continents to the global ocean that can have profound impact on issues such as coastal eutrophication and the development of hypoxic zones. LDE also record in their rapidly accumulating subaerial and subaqueous deltaic sediment deposits environmental changes such as continental-scale trends in climate and land-use in watersheds, frequency and magnitude of cyclonic storms, and sea-level change. The processes that control the transport and transformation of carbon in the active LDE and in the deltaic sediment deposit are also essential to our understanding of carbon sequestration and exchange with the world ocean—an important objective in global change research. U.S. efforts in global change science including the vital role of deltaic systems are emphasized in the North American Carbon Plan (www.carboncyclescience.gov). PMID:19435849

  9. A network model shows the importance of coupled processes in the microbial N cycle in the Cape Fear River Estuary

    NASA Astrophysics Data System (ADS)

    Hines, David E.; Lisa, Jessica A.; Song, Bongkeun; Tobias, Craig R.; Borrett, Stuart R.

    2012-06-01

    Estuaries serve important ecological and economic functions including habitat provision and the removal of nutrients. Eutrophication can overwhelm the nutrient removal capacity of estuaries and poses a widely recognized threat to the health and function of these ecosystems. Denitrification and anaerobic ammonium oxidation (anammox) are microbial processes responsible for the removal of fixed nitrogen and diminish the effects of eutrophication. Both of these microbial removal processes can be influenced by direct inputs of dissolved inorganic nitrogen substrates or supported by microbial interactions with other nitrogen transforming pathways such as nitrification and dissimilatory nitrate reduction to ammonium (DNRA). The coupling of nitrogen removal pathways to other transformation pathways facilitates the removal of some forms of inorganic nitrogen; however, differentiating between direct and coupled nitrogen removal is difficult. Network modeling provides a tool to examine interactions among microbial nitrogen cycling processes and to determine the within-system history of nitrogen involved in denitrification and anammox. To examine the coupling of nitrogen cycling processes, we built a nitrogen budget mass balance network model in two adjacent 1 cm3 sections of bottom water and sediment in the oligohaline portion of the Cape Fear River Estuary, NC, USA. Pathway, flow, and environ ecological network analyses were conducted to characterize the organization of nitrogen flow in the estuary and to estimate the coupling of nitrification to denitrification and of nitrification and DNRA to anammox. Centrality analysis indicated NH4+ is the most important form of nitrogen involved in removal processes. The model analysis further suggested that direct denitrification and coupled nitrification-denitrification had similar contributions to nitrogen removal while direct anammox was dominant to coupled forms of anammox. Finally, results also indicated that partial

  10. Remotely sensed variability of the suspended sediment concentration and its response to decreased river discharge in the Yangtze estuary and adjacent coast

    NASA Astrophysics Data System (ADS)

    Shen, Fang; Zhou, Yunxuan; Li, Jiufa; He, Qing; Verhoef, Wouter

    2013-10-01

    Satellite observation is an excellent tool for exploring the variability of the suspended sediment concentration (SSC) of turbid estuarine and coastal waters. We used a recently developed semi-empirical radiative transfer model combined with a multi-wavelength switching algorithm for the SSC retrieval from MEdium Resolution Imaging Spectrometer (MERIS) satellite data. This method can successfully retrieve SSC from satellite data in turbid estuarine and coastal waters with a wide range of sediment concentrations (20-2500 mg l-1) and is robust for quantifying realistic patterns of the surface sediment dynamics. The seasonal and annual variability of the MERIS-derived SSC from 2003 to 2010 were analysed in this work. Five regions-of-interest (ROIs) in the Yangtze estuary and coast are included in the analysis: the upper estuary, the lower estuary, the outer estuary, the Hangzhou Bay and the Qidong shore. The results reveal that the SSC of the upper estuary has significant seasonal and annual variations in response to seasonal cycling and annual fluctuation of the river discharge. A long-term continuing decrease of river discharge may cause an overall decline of the SSC in the entire estuary and adjacent areas. The existence of horizontal exchanges of the sediments between the Yangtze estuary and the Jiangsu coast implies that the decreased fluvial sediment loads of the estuary may partially be compensated by supplementing contributions from other origins.

  11. [Effects of Long-term Implementation of the Flow-Sediment Regulation Scheme on Grain and Clay Compositions of Inshore Sediments in the Yellow River Estuary].

    PubMed

    Wang, Miao-miao; Sun, Zhi-gao; Lu, Xiao-ning; Wang, Wei; Wang, Chuan-yuan

    2015-04-01

    Based on the laser particle size and X-ray diffraction (XRD) analysis, 28 sediment samples collected from the inshore region of the Yellow River estuary in October 2013 were determined to discuss the influence of long-term implementation of the flow-sediment regulation scheme (FSRS, initiated in 2002) on the distributions of grain size and clay components (smectite, illite, kaolinite and chlorite) in sediments. Results showed that, after the FSRS was implemented for more than 10 years, although the proportion of sand in inshore sediments of the Yellow River estuary was higher (average value, 23.5%) than those in sediments of the Bohai Sea and the Yellow River, silt was predominated (average value, 59.1%) and clay components were relatively low (average value, 17.4%). The clay components in sediments of the inshore region in the Yellow River estuary were close with those in the Yellow River. The situation was greatly changed due to the implementation of FSRS since 2002, and the clay components were in the order of illite > smectite > chlorite > kaolinite. This study also indicated that, compared to large-scale investigation in Bohai Sea, the local study on the inshore region of the Yellow River estuary was more favorable for revealing the effects of long-term implementation of the FSRS on sedimentation environment of the Yellow River estuary. PMID:26164898

  12. [Spectral absorption properties of the water constituents in the estuary of Zhujiang River].

    PubMed

    Wang, Shan-shan; Wang, Yong-bo; Fu, Qing-hua; Yin, Bin; Li, Yun-mei

    2014-12-01

    Spectral absorption properties of the water constituents is the main factor affecting the light field under the surface of the water and the spectrum above the surface of the water. Thus, the study is useful for understanding of the water spectral property and the remote reversing of water quality parameters. Absorption properties of total suspended particles, non-algal particles, phytoplankton and CDOM were analyzed using the 30 samples collected in July 2013 in the estuary of Zhujiang River. The results indicated that: (1) the non-algal particles absorption dominated the absorption of the total suspended particles; (2) the absorption coefficient of the non-algal particles, which mainly came from the terrigenous deposits, decreased exponentially from short to long wavelength. In addition, the average value and spatial variation of the slope S(d) were higher than those in inland case- II waters; (3) the absorption coefficient of phytoplankton in 440 nm showed a better polynomial relationship with chlorophyll a concentration, while the absorption coefficient of phytoplankton in 675 nm linearly related with the chlorophyll a concentration. Moreover, the influence of accessory pigments on phytoplankton absorption coefficient mainly existed in the range of short wavelength, and Chlorophyll a was the main influencing factor for phytoplankton absorption in long wavelength. The specific absorption coefficient of phytoplankton decreased the power exponentially with the increase of the chlorophyll a concentration; (4) CDOM mainly came from the terrigenous sources and its spectral curve had an absorption shoulder between 250-290 nm. Thus, a piecewise S(g) fitting function could effectively express CDOM absorption properties, i.e., M value and S(g) value in period A (240-260 nm) showed a strong positive correlation. The M value was low, and the humic acid had a high proportion in CDOM; (5) the non-algal particles absorption dominated the total absorption in the estuary of

  13. The Perennial Blooming of MGII and Their Correlation with MGI in the Pearl River Estuary, China

    NASA Astrophysics Data System (ADS)

    Xie, W.

    2015-12-01

    Marine Group (MG) I and MG II Archaea were first reported over two decades ago. While significant progress has been made on MG I, the progress on MG II has been noticeable slower. The common understanding is that while MG I mainly function as chemolithoautotrophs growing on ammonia and live predominantly in deeper water, MG II live heterotrophically and reside mostly in the photic zone. While some MG I lineages that could conduct ammonium oxidation are frequently found in terrestrial environments, MG II are exclusively found in marine environments and thus named Thalassoarchaea. A few studies showed MG IIs were sporadically blooming in coastal waters and may be influenced by the level of eutrophication between seasons, which inhibited the enrichment and cultivation for MGII. In this study, we quantified the abundance of planktonic MGI (represented by archaeal amoA gene) and MGII (16S rRNA gene) using qPCR in the water column of different salinities (A: 0.8‰; B: 18.1‰; C: 23.9‰: D: 31‰) in the Pearl River Estuary over a 12-month period. The results showed that the abundance of MGII in site C (8.5±10.1×107 copies/L) was significantly higher than the other three sites (A: 3.5±8.8×105 copies/L; B: 2.7±4.5×107 copies/L; D: 2.2±4.4×107 copies/L) in all seasons, indicating the perennial blooming of MGII that might be due to the optimal combination of available organic carbon and salinity at this site. We also observed that the correlation between MGI and MGII became better toward the marine water and was significant at site D (R2: A, 0.06; B, 0.1; C, 0.24; D, 0.64), indicating the potential functional relationship between them with increasing salinity. This allowed us to hypothesize that the growth of MGI in the coastal site is more dependent on release of ammonia from organic matter degradation by MGII and other heterotrophic organisms. The Pearl River estuary may be an ideal environment for testing this hypothesis, which may provide insight into the

  14. Controls on Bacterial Concentrations in Sediment Grab Samples from the Hudson River Estuary

    NASA Astrophysics Data System (ADS)

    Batta, J.; Mailloux, B. J.; Nitsche, F. O.; Kenna, T. C.; Ferguson, A. S.; Cheung, J.; Layton, A.

    2010-12-01

    High levels of fecal bacteria resulting from sewage-related pollution are often present in the Hudson River Estuary. Die-off of the fecal bacteria in surface waters is relatively rapid but the fecal bacteria can also attach to particles and settle. It is known that fecal bacteria are present in the shallow sediments but controls on their distribution have not been closely examined. The goal of this work is to examine the relationship between the concentration of fecal indicator bacteria and sediment properties including estimates of sediment age. Forty sediment surface grabs were obtained from the Hudson River Estuary. Twenty samples were collected from near the George Washington Bridge (GWB) and twenty samples from a 15 mile transect near Hudson New York. Concentrations of fecal indicator bacteria were determined by the cultured based Enterolert and Colilert tests (Idexx Laboratories) and molecular based techniques for E. coli and Bacteroides. Sediments were analyzed for total metals, total organic carbon, grain size, and gamma emitting radionuclides including Beryllium-7, Lead-210, and Cesium-137. Enterococcus was present in the samples with a geometric mean of 88 cells/g and a range of 4 to 817 cells /g. Culturable E. Coli was present in the samples with a geometric mean of 168 cells /g and a range of 5 to 2247 cells /g. Enterococcus concentrations were significantly higher (p<0.05) in the northern transect. Molecular based concentrations were determined for the GWB samples and were significantly higher than culture based concentrations. Bacteroides was present in the samples with a geometric mean of 1.1x106 copies/g and a range of 3.9x104 to 4.7x106 copies /g. Molecular E. Coli was present in the samples with a geometric mean of 3.0x106 copies/g and a range of 8.7x104 to 8.9x107 copies /g. The results clearly show that a significant amount of fecal bacteria are present in the sediments. Simple linear correlations between bacterial concentrations and sediment

  15. Net Subterranean Estuarine Export Fluxes of Dissolved Inorganic C, N, P, Si, and Total Alkalinity into the Jiulong River Estuary, China

    NASA Astrophysics Data System (ADS)

    Wang, G.; Wang, Z.; Zhai, W. D.; Moore, W. S.; Li, Q.; Yan, X.; Qi, D.; Jiang, Y.

    2014-12-01

    To evaluate geochemical impacts of the subterranean estuary (STE) on the Jiulong River estuary, China, we estimated seasonal fluxes of subterranean water discharge into the estuary based on the mass balance of radium isotopes and net subterranean export fluxes of dissolved inorganic C (DIC), N (DIN), Si (DSi), soluble reactive phosphorus (SRP), and total alkalinity (TA). Based on 226Ra data, the subterranean discharge (in 107 m3 d-1) was estimated to be 0.24~0.51 in the spring, 0.56~1.16 in the summer, 0.38~0.79 in the fall, and 0.22~0.45 in the winter. This was equivalent to 6-16% of the concomitant river discharge. The net spatially integrated material fluxes from the STE into the estuary were equivalent up to 51-89% of the concomitant riverine fluxes for DIC and TA, around 10-25% for DSi and DIN, and negligible for SRP. Paradoxically, the mixing lines along the salinity gradient revealed no apparent additions of these species. These additions are not revealed because the STE is a relatively small spatially-averaged source that spreads throughout the estuary in contrast to the major point sources of the river and the ocean for the estuary. Thus, despite apparent conservative mixing of DIC, DIN, and DSi, subterranean exports of these species into estuaries must be taken into account in evaluating geochemical impacts of estuarine exports on shelf waters.

  16. Freshwater fluxes in the Berau estuary and shelf during peak river discharge conditions

    NASA Astrophysics Data System (ADS)

    Van Der Vegt, M.; Tarya, A.; Hoitink, A.

    2011-12-01

    The Berau Continental Shelf is located close to the Equator in the Indonesian Archipelago, hosting a complex of coral reefs and atolls along its oceanic edge. It is important to understand how river water, sediments, and other materials derived from land are carried to reefs by physical mechanisms, since they can have beneficial as well as negative effects. Furthermore, at several of the atolls unique seagrass meadows are found. These ecosystems need exclusively marine conditions and are intolerant to freshwater. In the Berau Continental shelf much uncertainty remains about how much of the riverine water reaches the reefs and the atolls. In a recent study we showed that tides are the main contributor to the spreading of freshwater at the Berau Continental Shelf under average conditions: relatively small river discharge, weak winds, strong tides. A three-dimensional model (ECOMSED) was calibrated and validated with observational data collected in the context of the East Kalimantan Research Programme. Data-model comparison showed high skill scores and small systematic errors. Model analysis has shown that tides effect the plume by causing vertical mixing, by stratifying the plume due to tidal straining and by transporting freshwater. This causes the depth-integrated freshwater transport to be mainly north-eastward, toward the barrier reef. Under these average conditions freshwater does not reach the atolls. The main aim of this study is to study plume dynamics at the Berau shelf during peak river discharge and peak wind conditions. Because the Berau delta is urbanizing rapidly increasing peak river discharges and sediment loads are expected. In addition, although the yearly mean wind is small, peak wind events concurrent with peak floods might push the stratified top layer of the water column towards the reefs and atolls. Using the results of a hydrological model we estimated realistic peak values of the river discharge based on scenarios for the economical

  17. Aquatic ecology of the Elwha River estuary prior to dam removal: Chapter 7 in Coastal habitats of the Elwha River, Washington--biological and physical patterns and processes prior to dam removal

    USGS Publications Warehouse

    Duda, Jeffrey J.; Beirne, Matthew M.; Larsen, Kimberly; Barry, Dwight; Stenberg, Karl; McHenry, Michael L.

    2011-01-01

    The removal of two long-standing dams on the Elwha River in Washington State will initiate a suite of biological and physical changes to the estuary at the river mouth. Estuaries represent a transition between freshwater and saltwater, have unique assemblages of plants and animals, and are a critical habitat for some salmon species as they migrate to the ocean. This chapter summarizes a number of studies in the Elwha River estuary, and focuses on physical and biological aspects of the ecosystem that are expected to change following dam removal. Included are data sets that summarize (1) water chemistry samples collected over a 16 month period; (2) beach seining activities targeted toward describing the fish assemblage of the estuary and migratory patterns of juvenile salmon; (3) descriptions of the aquatic and terrestrial invertebrate communities in the estuary, which represent an important food source for juvenile fish and are important water quality indicators; and (4) the diet and growth patterns of juvenile Chinook salmon in the lower Elwha River and estuary. These data represent baseline conditions of the ecosystem after nearly a century of changes due to the dams and will be useful in monitoring the changes to the river and estuary following dam removal.

  18. Log Distribution, Persistence, and Geomorphic Function in Streams and Rivers, in the Northeastern U.S.

    NASA Astrophysics Data System (ADS)

    St Pierre, L.; Burchsted, D.; Warren, D.

    2015-12-01

    Large wood provides critical ecosystem services such as fish habitat, temperature regulation and bank stabilization. In the northeastern U.S., the distribution of large wood is documented; however, there is little understanding of the movement, longevity and geomorphic function. This research examines the hypothesis that tree species control the persistence and geomorphic function of instream wood in the Appalachian region of the northeastern U.S. To do this, we assessed size, location, and species of logs in New Hampshire rivers, including locations in the White Mountain National Forest (WMNF) where these data were collected ten years ago. We expanded the previous dataset to include assessment of geomorphic function, including creation of diversion channels, pool formation, and sediment storage, among others. We also added new sites in the WMNF and sites on a large rural river in southwestern NH to increase the range of geomorphic variables to now include: confined and unconfined channels; 1st to 4th order streams; low to high gradient; meandering, multithreaded, and straight channels; and land use such as historic logging, modern agriculture, and post-agricultural abandonment. At each study site, we located all large logs (>10cm diameter, > 1m length) and log jams (>3 accumulated logs that provide a geomorphic function) along 100m-700m reaches. We marked each identified log with a numbered tag and recorded species, diameter, length, orientation, GPS location, tag number, and photographs. We assessed function and accumulation, decay, stability, and source classes for each log. Along each reach we measured riparian forest composition and structure and channel width. Preliminary analysis suggests that tree species significantly affects the function of logs: yellow birch and American sycamore are highly represented. Additionally, geomorphic setting also plays a primary role, where unconfined reaches have large logs that provide important functions; those functions

  19. Daily rainfall variability over northeastern Argentina in the La Plata River basin.

    PubMed

    García, Norberto O; Pedraza, Raúl A

    2008-12-01

    We did a brief description of the climatic behavior and after this we analyzed the temporal variation in the total number of days a year with rainfall and the number of days a year with rainfall above the 100 mm threshold at the rain gauging stations in northeastern Argentina south of the La Plata River basin. The results show an increase both in the frequency of daily rainfall, especially during the winter season, and the frequency of days with heavy rainfall starting in the early 1970s. The increase in frequency of occurrence is more significant in the case of heavy rainfall. The annual maximum rainfall was calculated for periods of 1, 3, 5, 7, and 10 consecutive days at regional rain gauging stations for the respective historical periods, and the rain intensity-duration-return period curves (IDT) were determined on a frequency analysis. The IDT curves were compared with rainfall intensity-duration data of critical storms occurring in the last decades. We noticed that the rain intensities of critical storms (mostly convective) widely exceeded the intensities given by the 100-year IDT curves, particularly for short durations. The increase in both the frequency of heavy rainfall occurrence and rain intensity from the 1970s onward shows an increase in frequency and intensity of the meso-scale convective systems in the region resulting from climatic change. These systems tend to produce rainfall of very high intensity that is spatially concentrated and which generally produces significant floods in the local rivers. PMID:19076421

  20. Heavy metals associated with reduced sulfur in sediments from different deposition environments in the Pearl River estuary, China.

    PubMed

    Chen, Fanrong; Yang, Yongqiang; Zhang, Derong; Zhang, Ling

    2006-06-01

    Distribution of acid volatile sulfur (AVS) and the simultaneously extracted metals (SEM: Cu, Pb, Zn, Cd, Ni) in sediment profiles has been studied at five sites in Pearl River estuary, China. Of the five sampling locations, Nos.1 and 2 are in the middle shoal, Nos.3 and 4 in the west shoal and No. 5 locates to the south of the estuary. The AVS content in the sediments of the middle shoal varies in a small range (0.25-4.06 micromol g(-1)), while that of west shoal increases with depth from 0 to ultimately 26.09 micromol g(-1). The SEM concentration in the sediment profiles at location Nos. 1, 2 and 5 is generally in the range of 0.95+/-0.2 micromol g(-1) with a slight upward increase, while that in the sediment of west shallows are much higher (1.43-2.42 micromol g(-1)) with a significant upward increase, especially in the upper layer of ca. 15 cm. The observed upward increase of SEM content at all the sites implies that heavy metal contamination of sediment in the Pearl River estuary is increasing. Calculations of the excess heavy metal content which is defined by SEM-AVS molar difference suggests that the upper sediment in the Pearl River estuary, especially on the west shallows, could be a source of heavy metal contaminants and may cause toxicity to the benthos. The site-specific distribution patterns in the AVS and SEM profiles were interpreted according to the hydrogeochemistry of deposition environments. PMID:16767564

  1. Myrionecta Rubra Population Genetic Diversity and Its Cryptophyte Chloroplast Specificity in Recurrent Red Tides in the Columbia River Estuary

    SciTech Connect

    Herfort, Lydie; Peterson, Tawnya D.; McCue, Lee Ann; Crump, Byron C.; Prahl, Fredrick G.; Baptista, Antonio M.; Campbell, Victoria; Warnick, Rachel; Selby, Mikaela; Roegner, G. Curtis; Zuber, Peter A.

    2011-01-04

    For at least a decade, annually recurring blooms of the photosynthetic ciliate, Myrionecta rubra have been observed in the Columbia River estuary in late summer. In an effort to understand the dynamics of these blooms, we investigated the genetic variability of M. rubra and its cryptophyte plastids within three large estuarine blooms formed in consecutive years (2007-2009), and conducted a broader spatial survey along the coasts of Oregon/Washington. Analysis of the ‘18S-28S’ sequences specific for Mesodiniidae uncovered at least 7 variants of M. rubra within the Columbia River coastal margin in spring and summer, but only one of these M. rubra variants was implicated in estuary bloom formation. Using a multigene approach, we show that the bloom-forming variant of M. rubra appears to harbor the same cryptophyte chloroplast in recurring blooms. Analyses of chloroplast 16S rRNA, cryptophyte RuBisCO and Photosystem II D2 genes together suggest that the plastid is derived from Teleaulax amphioxeia. Free-living cells of this species and of other cryptophytes were practically absent from the bloom patches in the estuary main channels based on 18S rDNA sequence analyses. The respectively low and high proportions of T. amphioxeia nuclei and chloroplasts signals found in the M. rubra bloom of the Columbia River estuary in successive years supports the notion of a transient association between T. amphioxeia and the bloom-forming M. rubra variant, with loss of cryptophyte nuclei. The genetic variability of M. rubra uncovered here is relevant to the controversy in the literature regarding the cryptophyte /M. rubra association.

  2. Influence of small river derived sediment on the Northeastern South China Sea sedimentation processes in the last 40 K years

    NASA Astrophysics Data System (ADS)

    Cheng, Wan-Yen; Lin, Saulwood; Lou, Jiann-Yuh; Wei, Kuo-Yen; Liu, CharShine; Chen, Shing-Li; Wang, Yun-Shuen

    2015-04-01

    Small rivers derived particles are major source of sediment to the ocean in the present time. Small rivers in Taiwan are subjected to fast tectonic activity, high precipitation rate and erosion rate. The combined annual river particle load from small rivers on the Island of Taiwan is higher than that of the Mississippi River. A large fraction of those rivers particle may finding its way into the surrounding seas and ocean, e.g. South China Sea, East China Sea, and the Philippine Sea. Furthermore, due to the nature of particle transportation off rivers from Taiwan were connected by a number of canyon systems close by the river mouth, majority of those river particles were facilitated in delivering and deposited later further into the South China Sea deep basin. The objectives of this study are to understand spatial variations in sedimentation rates and to resolve the temporal differences in sedimentation in the Northeastern South China Sea region, and to evaluate influence of small river particles to the marginal sea. A set of cores was collected in overlying water depth within 1600 - 3300 m for mutilsensor core logging of magnetic susceptibility, density, and porosity. Foraminifera (G. sacculifer, G. conglobatus, O. universa) were picked and AMS C14 analyses for age determination. Grain size, organic carbon, carbonate and biogenic silica content were measured. The results show that large sedimentation rates difference existed in the study area. Earlier studies on sedimentation rate in the region west of our study area were in range of about 10 cm/kyr while our rates are about 20-40 cm/kyr and much higher near Taiwan. Bulk sedimentation rate were higher during the transition period between LGM and Holocene and lower during Holocene. Our results demonstrated that large quantity of particles from small rivers in Taiwan are and were major source of particle and are the dominating factor in controlling sediment deposition in the northeastern South China Sea.

  3. On the role of wind and tide in generating variability of Pearl River plume during summer in a coupled wide estuary and shelf system

    NASA Astrophysics Data System (ADS)

    Zu, Tingting; Wang, Dongxiao; Gan, Jianping; Guan, Weibing

    2014-08-01

    A numerical simulation of the buoyant river plume over the Pearl River Estuary (PRE) and adjacent shelf during a typical upwelling favorable wind period of the summer monsoon is utilized to explore the responses of the plume to wind and tide forcing. The model is forced with time-dependent river discharge, wind and tide, and it shows reasonable ability to capture the basic structure and responses of the plume. Additional numerical experiments that are forced without either wind or tide are used to evaluate the relative importance of wind and tide in generating plume variability. Results show that the vertical structure of the plume and the strength of the stratification in the estuary are determined by the combination of the buoyancy forcing associated with river discharge and tidal forcing, and vary with the advection process, while the horizontal shape and spreading of the plume over the shelf are highly influenced by the wind-driven coastal current, and are more susceptible to the change of vertical mixing. Mechanical energy analysis in each dynamical region (upper, middle, lower estuary, and shelf) reveals that this is because the system mainly gains energy from tide (wind) in the estuary (shelf), and loses energy to the bottom friction (internal-shear mixing) in the estuary (shelf). The largest forcing and dissipation terms in the middle PRE, and at the entrances of smaller estuaries such as Huang Mao Hai, are due to tidal forcing, which enables the middle PRE to serve dynamically as the entrance of an estuary, where the transition of the river plume into coastal buoyancy current usually takes place. In addition, the mixing efficiency increases from upper PRE to the shelf and from strong to weak mixing period, thus the plume in the well-mixed upper estuary is not as sensitive to the changes of wind and tide as that over the highly stratified shelf.

  4. Estuarine Habitats for Juvenile Salmon in the Tidally-Influenced Lower Columbia River and Estuary : Reporting Period September 15, 2008 through May 31, 2009.

    SciTech Connect

    Baptista, António M.

    2009-08-02

    This work focuses on the numerical modeling of Columbia River estuarine circulation and associated modeling-supported analyses conducted as an integral part of a multi-disciplinary and multi-institutional effort led by NOAA's Northwest Fisheries Science Center. The overall effort is aimed at: (1) retrospective analyses to reconstruct historic bathymetric features and assess effects of climate and river flow on the extent and distribution of shallow water, wetland and tidal-floodplain habitats; (2) computer simulations using a 3-dimensional numerical model to evaluate the sensitivity of salmon rearing opportunities to various historical modifications affecting the estuary (including channel changes, flow regulation, and diking of tidal wetlands and floodplains); (3) observational studies of present and historic food web sources supporting selected life histories of juvenile salmon as determined by stable isotope, microchemistry, and parasitology techniques; and (4) experimental studies in Grays River in collaboration with Columbia River Estuary Study Taskforce (CREST) and the Columbia Land Trust (CLT) to assess effects of multiple tidal wetland restoration projects on various life histories of juvenile salmon and to compare responses to observed habitat-use patterns in the mainstem estuary. From the above observations, experiments, and additional modeling simulations, the effort will also (5) examine effects of alternative flow-management and habitat-restoration scenarios on habitat opportunity and the estuary's productive capacity for juvenile salmon. The underlying modeling system is part of the SATURN1coastal-margin observatory [1]. SATURN relies on 3D numerical models [2, 3] to systematically simulate and understand baroclinic circulation in the Columbia River estuary-plume-shelf system [4-7] (Fig. 1). Multi-year simulation databases of circulation are produced as an integral part of SATURN, and have multiple applications in understanding estuary

  5. Distribution and contamination assessment of heavy metals in surface sediments of the Luanhe River Estuary, northwest of the Bohai Sea.

    PubMed

    Liu, Jinqing; Yin, Ping; Chen, Bin; Gao, Fei; Song, Hongying; Li, Meina

    2016-08-15

    33 surface sediment samples from the Luanhe River Estuary have been analyzed for heavy metals to evaluate the spatial distribution pattern and their potential ecological risk. Higher metal concentrations were found in the river mouth and southern areas where being covered by fine particulate matters. In comparison with the threshold effect level and the probable effect level, Cu, Pb, Cr, Ni, and As had occasionally adverse biological effects on the aquatic ecosystems. Both the enrichment factor and geoaccumulation index values show that all the regions have been weakly polluted by Pb, Hg, As, and Cd with an exception of being moderately to strongly polluted by Hg in the river mouth and southern areas. The sources of Zn, Ni, Cd, Hg, and Cr were mainly from the river input and coastal discharge, whereas Cu, Pb, and As were mainly derived from vehicle emissions, coal and oil combustion. PMID:27197763

  6. Mitochondrial genome sequence of Paramisgurnus dabryanus from the Yellow River estuary: implication for Cobitidae phylogeny.

    PubMed

    Zhu, Ming; Liu, Feng

    2016-07-01

    Paramisgurnus dabryanus Sauvage (Cobitidae, Cypriniformes) is a native large-scale loach widely distributed in main inland freshwater systems of China. The complete mitochondrial genome sequence of P. dabryanus from the Yellow River (YR) estuary was characterized in the present study. The circular mitogenome is 16 570 bp in size and contains two ribosomal RNA genes, 22 transfer RNA genes, and 13 protein-coding genes. The overall A + T content is 56.64% in the range of other Cobitidae studied. The mitogenome of P. dabryanus YR has an overall nucleotide sequence identity of 96.9% with that from Zhejiang, and 89.2% with that from Hubei. All the Misgurnus and Paramisgurnus species were clustered into two Misgurnus/Paramisgurnus complex clades with high bootstrap values based on the whole mitogenome sequences. The mitochondrial phylogenomic analysis indicates that the relationships in Cobitidae are inconsistent with the current classification system and taxonomic revision is required on the basis of molecular phylogeny and morphology. PMID:26162049

  7. Infrastructure for collaborative science and societal applications in the Columbia River estuary

    NASA Astrophysics Data System (ADS)

    Baptista, António M.; Seaton, Charles; Wilkin, Michael P.; Riseman, Sarah F.; Needoba, Joseph A.; Maier, David; Turner, Paul J.; Kärnä, Tuomas; Lopez, Jesse E.; Herfort, Lydie; Megler, V. M.; McNeil, Craig; Crump, Byron C.; Peterson, Tawnya D.; Spitz, Yvette H.; Simon, Holly M.

    2015-12-01

    To meet societal needs, modern estuarine science needs to be interdisciplinary and collaborative, combine discovery with hypotheses testing, and be responsive to issues facing both regional and global stakeholders. Such an approach is best conducted with the benefit of data-rich environments, where information from sensors and models is openly accessible within convenient timeframes. Here, we introduce the operational infrastructure of one such data-rich environment, a collaboratory created to support (a) interdisciplinary research in the Columbia River estuary by the multi-institutional team of investigators of the Science and Technology Center for Coastal Margin Observation & Prediction and (b) the integration of scientific knowledge into regional decision making. Core components of the operational infrastructure are an observation network, a modeling system and a cyber-infrastructure, each of which is described. The observation network is anchored on an extensive array of long-term stations, many of them interdisciplinary, and is complemented by on-demand deployment of temporary stations and mobile platforms, often in coordinated field campaigns. The modeling system is based on finiteelement unstructured-grid codes and includes operational and process-oriented simulations of circulation, sediments and ecosystem processes. The flow of information is managed through a dedicated cyber-infrastructure, conversant with regional and national observing systems.

  8. [Seasonal fluctuation of macrobenthos community in Jiuduansha intertidal wetland of Yangtze River Estuary].

    PubMed

    Zhou, Xiao; Ge, Zhenming; Shi, Wenyu; Wang, Tianhou; Cao, Dan; Zhou, Lichen

    2006-11-01

    From November 2004 to October 2005, an investigation was made on the seasonal fluctuation of macrobenthos community in the Jiuduansha intertidal wetland of Yangtze River Estuary, with the correlations between this fluctuation and sediment factors studied. 864 samples were collected seasonally from 216 sites in 7 sampling transects. A total of 30 species were identified, mainly belonging to Mollusca, Annelida, Crustacea and insect. The dominant species were Stenothyra glabra, Assiminea violacea, Potamocorbula ustulata, Glaucomya chinensis, and Ilyrplax deschampsi. In spring, macrobenthos had the highest density and biomass and the richest diversity, but in summer, the density and biomass were the lowest, the diversity was on a lower level, and the distribution was uneven. There were no significant differences in the species number and biomass between autumn and winter, but the density was higher in winter than in autumn. In spring, summer and autumn, the species number, density, and biomass of macrobenthos had no significant correlations with sediment factors, but in winter, macrobenthos density had significant correlations with the humidity and organic matter content of sediment. PMID:17269330

  9. Toxicity of sediment cores from Yangtze River estuary to zebrafish (Danio rerio) embryos.

    PubMed

    Wang, Peipei; Zhang, Lili; Liu, Li; Chen, Ling; Gao, Hongwen; Wu, Lingling

    2015-11-01

    Toxicity evaluation is an important segment in sediment quality monitoring in order to protect aquatic organisms and human health. The purpose of this study is to assess the toxicity of sediments from three sediment cores in Yangtze River Estuary, China, using the zebrafish (Danio rerio) embryo tests. Fertilized zebrafish eggs were exposed to both whole sediments and sediment organic extracts prepared from collected sediments, in order to provide a comprehensive and realistic insight into the bioavailable toxicity potential of the sediments. As end points, development parameters (mortality, hatching rate, and abnormality) in the developing embryos were recorded during the 96-h exposure. The results showed that some samples increased mortality, inhibited the hatching of embryos, and induced morphological abnormalities. The embryonic toxicities presented serrated changes and irregular distribution with depth, which may be related to hydrodynamic effect and unstable environmental input. However, lethal and sub-lethal effects were more significant at the sub-surface sediments (10∼40 cm), which indicated that the pollution is more serious in recent decades. PMID:25163567

  10. Identification and apportionment of hazardous elements in the sediments in the Yangtze River estuary.

    PubMed

    Wang, Jiawei; Liu, Ruimin; Wang, Haotian; Yu, Wenwen; Xu, Fei; Shen, Zhenyao

    2015-12-01

    In this study, positive matrix factorization (PMF) and principal components analysis (PCA) were combined to identify and apportion pollution-based sources of hazardous elements in the surface sediments in the Yangtze River estuary (YRE). Source identification analysis indicated that PC1, including Al, Fe, Mn, Cr, Ni, As, Cu, and Zn, can be defined as a sewage component; PC2, including Pb and Sb, can be considered as an atmospheric deposition component; and PC3, containing Cd and Hg, can be considered as an agricultural nonpoint component. To better identify the sources and quantitatively apportion the concentrations to their sources, eight sources were identified with PMF: agricultural/industrial sewage mixed (18.6 %), mining wastewater (15.9 %), agricultural fertilizer (14.5 %), atmospheric deposition (12.8 %), agricultural nonpoint (10.6 %), industrial wastewater (9.8 %), marine activity (9.0 %), and nickel plating industry (8.8 %). Overall, the hazardous element content seems to be more connected to anthropogenic activity instead of natural sources. The PCA results laid the foundation for the PMF analysis by providing a general classification of sources. PMF resolves more factors with a higher explained variance than PCA; PMF provided both the internal analysis and the quantitative analysis. The combination of the two methods can provide more reasonable and reliable results. PMID:26511260

  11. Abundance exchange models of fish assemblages along the Hudson River Estuary Gradient, New York.

    PubMed

    Singkran, Nuanchan; Bain, Mark B

    2008-01-01

    The spatially explicit abundance exchange model (AEM) was built for four fish species: winter flounder (Pseudopleuronectes americanus), Atlantic silverside (Menidia menidia), eastern silvery minnow (Hybognathus regius), and striped bass (Morone saxatilis) along the Hudson River estuary gradient, New York. The fish and habitat data during 1974-1997 were used to develop and calibrate the AEM; and the fish data during 1998-2001 was used to validate the model. Preference indexes of fish species for dissolved oxygen, salinity, water temperature, and bottom substrates along the gradient were estimated; and these were used to compute habitat preference (HP) of the associated fish species. The species HP was a key variable in the AEM to quantify abundance and distribution patterns of the associated species along the gradient. The AEM could efficiently predict abundance and distribution patterns of all modeled species except striped bass. The model ability for predicting a local distribution range of a fish species with broad tolerance on changing environment like striped bass should be improved. PMID:19092189

  12. Physiological characterization of juvenile Chinook salmon utilizing different habitats during migration through the Columbia River Estuary.

    PubMed

    Hanson, Kyle C; Ostrand, Kenneth G; Glenn, Richard A

    2012-11-01

    Although off-channel habitats in the estuaries of large rivers impart many benefits to fish that rear within them, it is less clear how these habitats benefit migrating anadromous species that utilize these habitats for short periods of time. We evaluated the physiological correlates (nutritional condition, growth, and smoltification) of habitat utilization (main-channel vs. off-channel) by juvenile Chinook salmon Oncorhynchus tshawytscha during emigration. Fish from the off-channel had higher condition factor scores and relative weights than fish from the main-channel throughout the study period. Plasma triglyceride and protein concentrations were significantly different between habitat types and across the sampling period, suggesting that fish utilizing the off-channel habitats were compensating for energy losses associated with emigration as compared to main-channel fish. Growth potential (RNA to DNA ratio) did not vary by habitat or sampling period, presumably due to short residency time. There were no differences in osmoregulatory capacity (gill Na(+), K(+)-ATPase activity) based on habitat type. Our results indicate that short-term off-channel habitat use may mitigate for energy declines incurred during migration, but likely does not impart significant gains in energy stores or growth. PMID:22842392

  13. [Porewater Dissolved Methane in Cyperus malaccensis Marshes Along Salinity Gradient in the Minjiang River Estuary].

    PubMed

    Yang, Ping; Zhang, Zi-chuan; Du, Wei-ning; Huang, Jia-fang; Tong, Chuan

    2015-10-01

    Physicochemical properties of soil and dissolved methane concentrations of porewater in the sediments of the Cyperus malaccensis marshes along a salinity gradient in the Minjiang River estuary were evaluated, and the spatial-temporal characteristics and main impact factors were discussed. The average concentrations of dissolved methane in porewater were 331.18, 299.94 and 638.58 μmol x L(-1), respectively in the Shanyutan, Bianfuzhou and Xiayangzhou wetlands in summer. In the winter, they were 9.04, 266.67 and 322.68 μmol x L(-1), respectively. The dissolved methane concentration in porewater was higher in summer than those in winter (P < 0.05). Overall, the concentrations of dissolved methane in porewatdr showed an increasing trend from brackish to freshwater marshes. Multivariate statistics analysis showed that the concentrations of dissolved methane in porewater was positively correlated with soils temperature and DOC (P < 0.05), but negatively correlated with soils pH, salinity, and the concentrations of porewater SO4(2-) and Cl-. Spatial-temporal distribution of porewater dissolved methane in estuarine marshes represents a final result of multiple factors, including soil physicochemical properties and hydrodynamic condition. PMID:26841594

  14. Body condition and gametogenic cycle of Galatea paradoxa (Mollusca: Bivalvia) in the Volta River estuary, Ghana

    NASA Astrophysics Data System (ADS)

    Adjei-Boateng, D.; Wilson, J. G.

    2013-11-01

    The reproductive cycle of Galatea paradoxa which is the basis for an artisanal fishery in the Volta River estuary, Ghana, was studied using condition indices and histological methods from March 2008 to July 2009. The cycle is annual with a single spawning event between June and October. Gametogenesis starts in November progressing steadily to a peak in June-July when spawning begins until October when the animal is spent. The condition indices (shell-free wet weight/total wet weight, ash-free dry weight/shell weight and gonad wet weight/shell weight) showed a clear relationship with the gametogenic stage rising from a minimum at stage (I) start of gametogenesis, to their highest values at stages (IIIA) ripe and (IIIB) start of spawning before declining significantly to stage (IV) spent.It is suggested that condition index may prove a valuable technique in fishery management to recognise the reproductive stages of G. paradoxa as it is less expensive and time consuming than histological techniques in addition to being easier to teach to non-specialists. The data presented in this study provide information on the timing of spawning events for G. paradoxa, which is necessary for developing sustainable management strategies and selection of broodstock for aquaculture.

  15. Zooplankton community analysis in the Changjiang River estuary by single-gene-targeted metagenomics

    NASA Astrophysics Data System (ADS)

    Cheng, Fangping; Wang, Minxiao; Li, Chaolun; Sun, Song

    2014-07-01

    DNA barcoding provides accurate identification of zooplankton species through all life stages. Single-gene-targeted metagenomic analysis based on DNA barcode databases can facilitate longterm monitoring of zooplankton communities. With the help of the available zooplankton databases, the zooplankton community of the Changjiang (Yangtze) River estuary was studied using a single-gene-targeted metagenomic method to estimate the species richness of this community. A total of 856 mitochondrial cytochrome oxidase subunit 1 (cox1) gene sequences were determined. The environmental barcodes were clustered into 70 molecular operational taxonomic units (MOTUs). Forty-two MOTUs matched barcoded marine organisms with more than 90% similarity and were assigned to either the species (similarity>96%) or genus level (similarity<96%). Sibling species could also be distinguished. Many species that were overlooked by morphological methods were identified by molecular methods, especially gelatinous zooplankton and merozooplankton that were likely sampled at different life history phases. Zooplankton community structures differed significantly among all of the samples. The MOTU spatial distributions were influenced by the ecological habits of the corresponding species. In conclusion, single-gene-targeted metagenomic analysis is a useful tool for zooplankton studies, with which specimens from all life history stages can be identified quickly and effectively with a comprehensive database.

  16. Methane (CH4) emission from a tidal marsh in the Min River estuary, southeast China.

    PubMed

    Tong, Chuan; Wang, Wei-Qi; Zeng, Cong-Sheng; Marrs, Rob

    2010-01-01

    The total methane emission to the atmosphere and hydrosphere, and its seasonal variation, were estimated using an enclosed static chamber technique from a tidal marshes dominated by Phragmites australis (common reed) in the Min River estuary, southeast China. Measurements were taken at three tidal stages (before flood, during the flooding and ebbing process, and after ebb). Potential rates of methane production from the marsh sediment layers were also measured using an incubation technique. This P. australis tidal marsh was a net methane source, emitting 32.59 and 6.87 g CH(4) x m(-2) x yr(-1) to the atmosphere and hydrosphere, respectively. There was considerable monthly variation with emissions greater before flood in some months, whereas at other months emission was greater after ebb. The average methane fluxes were 5.13, 5.06 and 4.74 mg CH(4) m(-2) h(-1) before flood, during flooding and ebbing, and after ebb, respectively. Emissions to the tidewater and the atmosphere during the flooding and ebbing process were 2.98 and 2.08 mg CH(4) m(-2) h(-1),respectively. Sediment methane production potential (0-40 cm depth) ranged from 0.028-0.123 micro g CH(4) x g(-1) x d(-1), with the greatest production was in the surface soil. Methane fluxes had a significant correlation with atmospheric, sediment temperature and above ground biomass. The implications of these data for global warming are discussed briefly. PMID:20390897

  17. Lower Columbia River and Estuary Ecosystem Restoration Program Reference Site Study: 2011 Restoration Analysis - FINAL REPORT

    SciTech Connect

    Borde, Amy B.; Cullinan, Valerie I.; Diefenderfer, Heida L.; Thom, Ronald M.; Kaufmann, Ronald M.; Zimmerman, Shon A.; Sagar, Jina; Buenau, Kate E.; Corbett, C.

    2012-05-31

    The Reference Site (RS) study is part of the research, monitoring, and evaluation (RME) effort developed by the Action Agencies (Bonneville Power Administration [BPA], U.S. Army Corps of Engineers, Portland District [USACE], and U.S. Bureau of Reclamation) in response to Federal Columbia River Power System (FCRPS) Biological Opinions (BiOp). While the RS study was initiated in 2007, data have been collected at relatively undisturbed reference wetland sites in the LCRE by PNNL and collaborators since 2005. These data on habitat structural metrics were previously summarized to provide baseline characterization of 51 wetlands throughout the estuarine and tidal freshwater portions of the 235-km LCRE; however, further analysis of these data has been limited. Therefore, in 2011, we conducted additional analyses of existing field data previously collected for the Columbia Estuary Ecosystem Restoration Program (CEERP) - including data collected by PNNL and others - to help inform the multi-agency restoration planning and ecosystem management work underway in the LCRE.

  18. Diet and feeding periodicity of ruffe in the St. Louis River estuary, Lake Superior

    USGS Publications Warehouse

    Ogle, Derek H.; Selgeby, James H.; Newman, Raymond M.; Henry, Mary G.

    1995-01-01

    Ruffe Gymnocephalus cernuus, a percid native to Europe and Asia, is established in the Lake Superior drainage and could have negative impacts on native fish through competition for forage and predation on fish eggs. We investigated the diet of ruffes in the 4,654-ha St. Louis River estuary in May–October 1989–1990 and the feeding periodicity of ruffes in two adjacent habitats during five 24-h periods in summers 1990–1991. Ruffes were primarily benthophagous. Age-0 ruffes fed mostly on cladocerans and copepods in early summer and midge larvae (Chironomidae) in late summer and fall. Adult ruffes less than 12 cm fed mostly on midges and other macrobenthos but also consumed large numbers of microcrustaceans. Adult ruffes 12 cm and larger fed mostly on midges, burrowing mayflies Hexagenia spp., and caddisflies (Trichoptera). Ruffes consumed few fish eggs. Adult ruffes in deeper waters and all age-0 ruffes fed throughout the day as indicated by weight patterns of stomach contents. However, adult ruffes generally moved to shallower waters at night to feed most heavily. Results of this study indicate that ruffes will probably compete with other benthic-feeding fishes such as yellow perch Perca flavescens and trout-perch Percopsis omiscomaycus.

  19. Distribution and risk assessment of 82 pesticides in Jiulong River and estuary in South China.

    PubMed

    Zheng, Senllin; Chen, Bin; Qiu, Xiaoyan; Chen, Meng; Ma, Zhiyuan; Yu, Xingguang

    2016-02-01

    To discover the distribution and risk of pesticides in Jiulong River and estuary, the residues of 102 pesticides were analyzed in water, sediment and clam samples collected from 35 sites in different seasons. A total number of 82 pesticides were detected and the occurrence and the risk to human and fish were assessed. Most of pesticides with high frequency were medium or low toxic except for DDTs. DDTs were the significant contaminant and the widely used dicofol was the new source of DDTs. The spatial and seasonal variation of pesticide distribution was linked with the distribution of orchards and farmlands. Health risk from river water consumption was low (RQ < 0.1) while that from clam consumption was medium (RQ = 0.84). Pesticides in water posed great risk to fish and among the 76 water samples analyzed, 65 of them showed high risk (RQ > 1) and 6 showed medium risk (0.1 ≤ QR < 1). The single chemical posed high risk to fish included DDTs, triazophos, fenvalerate, bifenthrin and cyfluthrin, and those showed medium risk included dicofol, butachlor, isocarbophos, terbufos and cyhalothrin. There were 14 single pesticides detected with concentration above 100 ng L(-1) in this study and the pesticide with the highest concentration was procymidone (3904 ng L(-1)). Further experiments illustrated that procymidone could disrupt the expression of vitellogenin in the estuarine fish even at environmental concentrations. DDTs, dicofol, triazophos, isocarbophos, terbufos, cyfluthrin, bifenthrin, fenvalerate, cyhalothrin, butachlor and procymidone have become the significant pesticides and should be considered in aquatic ecosystem risk management. PMID:26461443

  20. Conjunctive-use optimization model of the Mississippi River Valley alluvial aquifer of northeastern Arkansas

    USGS Publications Warehouse

    Czarnecki, John B.; Clark, Brian R.; Reed, Thomas B.

    2003-01-01

    The Mississippi River Valley alluvial aquifer is a water-bearing assemblage of gravels and sands that underlies about 32,000 square miles of Missouri, Kentucky, Tennessee, Mississippi, Louisiana, and Arkansas. Because of the heavy demands placed on the aquifer, several large cones of depression over 100 feet deep have formed in the potentiometric surface, resulting in lower well yields and degraded water quality in some areas. A ground-water flow model of the alluvial aquifer was previously developed for an area covering 14,104 square miles, extending northeast from the Arkansas River into the northeast corner of Arkansas and parts of southeastern Missouri. The flow model showed that continued ground-water withdrawals at rates commensurate with those of 1997 could not be sustained indefinitely without causing water levels to decline below half the original saturated thickness of the aquifer. To develop estimates of withdrawal rates that could be sustained in compliance with the constraints of critical ground-water area designation, conjunctive-use optimization modeling was applied to the flow model of the alluvial aquifer in northeastern Arkansas. Ground-water withdrawal rates form the basis for estimates of sustainable yield from the alluvial aquifer and from rivers specified within the alluvial aquifer model. A management problem was formulated as one of maximizing the sustainable yield from all ground-water and surface-water withdrawal cells within limits imposed by plausible withdrawal rates, and within specified constraints involving hydraulic head and streamflow. Steady-state flow conditions were selected because the maximized withdrawals are intended to represent sustainable yield of the system (a rate that can be maintained indefinitely). Within the optimization model, 11 rivers are specified. Surface-water diversion rates that occurred in 2000 were subtracted from specified overland flow at the appropriate river cells. Included in these diversions were the

  1. Evidencing the natural and anthropogenic processes controlling trace metals dynamic in a highly stratified estuary: The Krka River estuary (Adriatic, Croatia).

    PubMed

    Cindrić, Ana-Marija; Garnier, Cédric; Oursel, Benjamin; Pižeta, Ivanka; Omanović, Dario

    2015-05-15

    Distributions of trace metals (TM), organic carbon, SPM and physico-chemical parameters were studied in the highly stratified Krka River estuary in winter/summer periods. The non-conservative behaviour of Zn, Cd, Pb and Cu in the brackish layer (plume), easily spotted due to very low inputs by the river, was mainly caused by their inputs from the pleasure boats, nautical marinas and harbour (e.g. release from antifouling paints). Contrarily, Ni and Co followed near-conservative behaviour. The extremely low SPM discharged by the river, resulted in a predominant dissolved fraction (>80%) of all TM, except Pb. Vertical scavenging, coupled with the long residence time, caused accumulation and progressive upstream increase of TM and SPM in the bottom seawater. Decrease of distribution coefficient (KD) in the brackish layer for winter period was ascribed to the change of SPM nature (terrestrial vs. biogenic), whereas a variable and increased biogenic component of SPM caused scattered KDs in summer. PMID:25752536

  2. Mesozooplankton abundance in relation to the chlorophyll maximum in the Neuse River Estuary, North Carolina, USA: Implications for trophic dynamics

    NASA Astrophysics Data System (ADS)

    Kimmel, David G.; McGlaughon, Benjamin D.; Leonard, Jeremy; Paerl, Hans W.; Taylor, J. Christopher; Cira, Emily K.; Wetz, Michael S.

    2015-05-01

    Estuaries often have distinct zones of high chlorophyll a concentrations, known as chlorophyll maximum (CMAX). The persistence of these features is often attributed to physical (mixing and light availability) and chemical (nutrient availability) features, but the role of mesozooplankton grazing is rarely explored. We measured the spatial and temporal variability of the CMAX and mesozooplankton community in the eutrophic Neuse River Estuary, North Carolina. We also conducted grazing experiments to determine the relative impact of mesozooplankton grazing on the CMAX during the phytoplankton growing season (spring through late summer). The CMAX was consistently located upriver of the zone of maximum zooplankton abundance, with an average spatial separation of 18 km. Grazing experiments in the CMAX region revealed negligible effect of mesozooplankton on chlorophyll a during March, and no effect during June or August. These results suggest that the spatial separation of the peak in chlorophyll a concentration and mesozooplankton abundance results in minimal impact of mesozooplankton grazing, contributing to persistence of the CMAX for prolonged time periods. In the Neuse River Estuary, the low mesozooplankton abundance in the CMAX region is attributed to lack of a low salinity tolerant species, predation by the ctenophore Mnemiopsis leidyi, and/or physiologic impacts on mesozooplankton growth rates due to temperature (in the case of low wintertime abundances). The consequences of this lack of overlap result in exacerbation of the effects of eutrophication; namely a lack of trophic transfer to mesozooplankton in this region and the sinking of phytodetritus to the benthos that fuels hypoxia.

  3. [Spatial-temporal distributions of dissolved inorganic carbon and its affecting factors in the Yellow River estuary].

    PubMed

    Guo, Xing-Sen; Lü, Ying-Chun; Sun, Zhi-Gao; Wang, Chuan-Yuan; Zhao, Quan-Sheng

    2015-02-01

    Estuary is an important area contributing to the global carbon cycle. In order to analyze the spatial-temporal distribution characteristics of the dissolved inorganic carbon (DIC) in the surface water of Yellow River estuary. Samples were collected in spring, summer, fall, winter of 2013, and discussed the correlation between the content of DIC and environmental factors. The results show that, the DIC concentration of the surface water in Yellow River estuary is in a range of 26.34-39.43 mg x L(-1), and the DIC concentration in freshwater side is higher than that in the sea side. In some areas where the salinity is less than 15 per thousand, the DIC concentration appears significant losses-the maximum loss is 20.46%. Seasonal distribution of performance in descending order is spring, fall, winter, summer. Through principal component analysis, it shows that water temperature, suspended solids, salinity and chlorophyll a are the main factors affecting the variation of the DIC concentration in surface water, their contribution rate is as high as 83% , and alkalinity, pH, dissolved organic carbon, dissolved oxygen and other factors can not be ignored. The loss of DIC in the low area is due to the calcium carbonate sedimentation. DIC presents a gradually increasing trend, which is mainly due to the effects of water retention time, temperature, outside input and environmental conditions. PMID:26031070

  4. Dissolved inorganic carbon (DIC) and its δ13C in the Ganga (Hooghly) River estuary, India: Evidence of DIC generation via organic carbon degradation and carbonate dissolution

    NASA Astrophysics Data System (ADS)

    Samanta, Saumik; Dalai, Tarun K.; Pattanaik, Jitendra K.; Rai, Santosh K.; Mazumdar, Aninda

    2015-09-01

    In this study, we present comprehensive data on dissolved Ca, dissolved inorganic carbon (DIC) and its carbon isotope composition (δ13CDIC) of (i) the Ganga (Hooghly) River estuary water sampled during six seasons of contrasting water discharge over 2 years (2012 and 2013), (ii) shallow groundwater from areas adjacent to the estuary and (iii) industrial effluent water and urban wastewater draining into the estuary. Mass balance calculations indicate that processes other than the conservative mixing of seawater and river water are needed to explain the measured DIC and δ13CDIC. Results of mixing calculations in conjunction with the estimated undersaturated levels of dissolved O2 suggest that biological respiration and organic carbon degradation dominate over biological production in the estuary. An important outcome of this study is that a significant amount of DIC and dissolved Ca is produced within the estuary at salinity ⩾10, particularly during the monsoon period. Based on consideration of mass balance and a strong positive correlation observed between the "excess" DIC and "excess" Ca, we contend that the dominant source of DIC generated within the estuary is carbonate dissolution that is inferred to be operating in conjunction with degradation of organic carbon. Calculations show that groundwater cannot account for the observed "excess" Ca in the high salinity zone. Estimated DIC contributions from anthropogenic activity are minor, and they constitute ca. 2-3% of the river water DIC concentrations. The estimated annual DIC flux from the estuary to the Bay of Bengal is ca. (3-4) × 1012 g, of which ca. 40-50% is generated within the estuary. The monsoon periods account for the majority (ca. 70%) of the annual DIC generation in the estuary. The annual DIC flux from the Hooghly estuary accounts for ca. 1% of the global river DIC flux to the oceans. This is disproportionately higher than the water contribution from the Hooghly River to the oceans, which

  5. Aquatic Vegetation of the St. Louis River Estuary: Initial Analysis of Point-intercept Data Collected in 2010 for Restoration Modeling.

    EPA Science Inventory

    A new effort to model aquatic vegetation patterns in the St. Louis River Estuary was initiated in summer of 2010 for the purpose of informing wetland restoration planning in the St. Louis River Area of Concern (AOC) at 40th Avenue West in Duluth. Aquatic vascular plants were doc...

  6. Simulation of potential oyster density with variable freshwater inflow (1965-2000) to the Caloosahatchee River Estuary, southwest Florida, USA.

    PubMed

    Buzzelli, Christopher; Doering, Peter H; Wan, Yongshan; Gorman, Patricia; Volety, Aswani

    2013-10-01

    Oyster beds are disappearing worldwide through a combination of over-harvesting, diseases, and salinity alterations in the coastal zone. Sensitivity of oysters to variable discharge and salinity is particularly acute in small sub-tropical estuaries subject to regulated freshwater releases. South Florida has sub-tropical estuaries where watershed flood control sometimes results in excessive freshwater inflow to estuaries during the wet season (May-Oct) and reduced discharge and increased salinities in the dry season (Nov-Apr). The potential to reserve freshwater accumulated during the wet season could offer the capacity to regulate freshwater at different temporal scales, thus optimizing salinity conditions for estuarine biota. The goal of this study was to use simulation modeling to explore the effects of freshwater inflows and salinity on adult oyster survival in the Caloosahatchee River Estuary (CRE) in southwest Florida. Water managers derived three different freshwater inflow scenarios for the CRE based on historical and modified watershed attributes for the time period of 1965-2000. Three different salinity time series were generated from the inflow scenarios at each of three sites in the lower CRE and used to conduct nine different oyster simulations. Overall, the predicted densities of adult oysters in the upstream site were 3-4 times greater in seasons that experienced reduced freshwater inflow (e.g., increased salinity) with oyster density in the lower estuary much less influenced by the inflows. Potential storage of freshwater reduced the frequency of extreme flows in the wet season and helped to maintain minimum inflow in the dry season near the estuarine mouth. Analyses of inflows indicated that discharges ranging from 0 to 1,500 cfs could promote favorable salinities of 10-25 in the lower CRE depending on wet versus dry season climatic conditions. This range of inflows is similar to that derived in other studies of the CRE and emphasizes the value of

  7. Pore water nutrient characteristics and the fluxes across the sediment in the Pearl River estuary and adjacent waters, China

    NASA Astrophysics Data System (ADS)

    Zhang, Ling; Wang, Lu; Yin, Kedong; Lü, Ying; Zhang, Derong; Yang, Yongqiang; Huang, Xiaoping

    2013-11-01

    Spatio-temporal distribution of pore water nutrients and the fluxes at the sediment-water interface (SWI) were investigated to probe into the geochemical behavior of nutrients associated with early diagenesis of organic matter (OM), and to study the accumulation and transformation processes of nutrients at the SWI, as well as to discuss the impact of riverine inputs on nutrients in the Pearl River estuary (PRE) and adjacent offshore areas. Nutrient concentrations decreased from the upper to the lower reaches of the estuary, suggesting that there was a high input of anthropogenic nutrients and the estuary was acting as a nutrient sink. Dissolved inorganic nitrogen (DIN: the sum of NH4-N, NO3-N and NO2-N) concentrations in the water column and the pore water were higher in the estuary than at offshore areas due to the riverine discharge and the high accumulation rate in the estuary. NO3-N concentration was the highest of the three forms of DIN in the overlying water and showed a sharp decrease from the surficial sediment with increasing sediment depth, indicating that there was strong denitrification at the SWI. NH4-N, mainly deriving from the anaerobic degradation of OM, was the main form of DIN in the pore water and increased with depth. Negative NO3-N fluxes (into the sediment) and positive NH4-N fluxes (from the sediment) were commonly observed from incubation experiments, indicating the denitrification occurred at the SWI. DIN flux suggested that the sediment was a sink of DIN in spring, however, the sediment was the source of DIN in summer and winter. Nutrients dominantly diffused out of the sediment, suggesting that the sediment was the source of nutrients in spring at adjacent offshore areas. The fluxes directed that PO4-P mainly diffused into the sediment while SiO4-Si mainly diffused out of the sediment.

  8. The effects of estuarine processes on the fluxes of inorganic and organic carbon in the Yellow River estuary

    NASA Astrophysics Data System (ADS)

    Gu, Dianjun; Zhang, Longjun; Jiang, Liqing

    2009-12-01

    Riverine carbon flux is an important component of the global carbon cycle. The spatial and temporal variations of organic and inorganic carbon were examined during both dry and wet seasons in the Yellow River estuary. Concentrations of dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC) in the Yellow River during dry seasons were higher than those during wet seasons. The effective concentrations of DOC (CDOC*) were higher than the observed DOC at zero salinity. This input of DOC in the Yellow River estuary was due to sediment desorption processes in low salinity regions. In contrast to DOC, the effective concentrations of DIC were 10% lower than the DIC measured at freshwater end, and the loss of DIC was caused by CaCO3 precipitation in low salinity region. Particulate organic carbon (POC) and particulate inorganic carbon (PIC) contents of the particles stabilized to constant values (0.5%±0.05% and 1.8%±0.2%, respectively) within the turbidity maximum zone (TMZ) and showed no noticeable seasonal variations. A rapid drop of PIC and rise of POC occurred simultaneously outside the TMZ due to an intense dilution of riverine inorganic-rich particles being transported into a pool of aquatic organic-poor particles outside the TMZ. Annually, the Yellow River transported 6.95×105 t of DIC, 0.64×105 t of DOC, 78.58×105 t of PIC and 2.29×105 t of POC to the sea.

  9. A study of anthropogenic and climatic disturbance of the New River Estuary using a Bayesian belief network.

    PubMed

    Nojavan A, Farnaz; Qian, Song S; Paerl, Hans W; Reckhow, Kenneth H; Albright, Elizabeth A

    2014-06-15

    The present paper utilizes a Bayesian Belief Network (BBN) approach to intuitively present and quantify our current understanding of the complex physical, chemical, and biological processes that lead to eutrophication in an estuarine ecosystem (New River Estuary, North Carolina, USA). The model is further used to explore the effects of plausible future climatic and nutrient pollution management scenarios on water quality indicators. The BBN, through visualizing the structure of the network, facilitates knowledge communication with managers/stakeholders who might not be experts in the underlying scientific disciplines. Moreover, the developed structure of the BBN is transferable to other comparable estuaries. The BBN nodes are discretized exploring a new approach called moment matching method. The conditional probability tables of the variables are driven by a large dataset (four years). Our results show interaction among various predictors and their impact on water quality indicators. The synergistic effects caution future management actions. PMID:24814252

  10. Exploration of Salt Wedge Dynamics in the Columbia River Estuary Using Optical Measurements of Internal Ship Wakes.

    NASA Astrophysics Data System (ADS)

    Holman, R. A.; Greydanus, S. J.

    2014-12-01

    In May of 2013 and beyond, Argus optical measurements of the mouth of the Columbia River estuary and plume were collected as part of the RIVET II multi-investigator field experiment. One surprise was the strength of eddy and internal wave signatures observed in movies computed from one-minute averages of high-frequency snapshots (such that gravity waves were averaged out but slicks and variable surface roughness remained). In particular, passing ships left wakes that propagated away at speeds on the order of 0.5 m/s, much slower than gravity waves and presumably surface manifestations of internal waves associated with the time-varying salt-wedge. Thus, these internal ship wakes appear to act as probes of internal stratification dynamics. This paper will explore the time variations of these internal wakes and relate them to corresponding variations in the estuary salt wedge.

  11. Factors affecting the distribution and abundance of Macrobrachium petersi (Hilgendorf) in the Keiskamma River and estuary, South Africa

    NASA Astrophysics Data System (ADS)

    Read, G. H. L.

    1985-09-01

    A dry (1979-1980) and a wet (1980-1981) season had a marked effect on the freshwater inflow into the Keiskamma estuary. Under low inflow conditions, which results in elevated salinities in the upper reaches, an upstream migration of adult Macrobrachium petersi (Hilgendorf) to freshwater takes place. During periods of increased river inflow adult M. petersi move downstream to the more saline reaches of the estuary. These two migratory responses have been interpreted as (a) a breeding migration under high inflow conditions which ensures that larvae are in close proximity to salinities that favour growth and development, and (b) an adult upstream migration back to freshwater to escape elevated estuarine salinities as a result of the low freshwater inflow.

  12. Sources and distribution of organic matter in a river-dominated estuary (Winyah Bay, SC, USA)

    NASA Astrophysics Data System (ADS)

    Goñi, Miguel A.; Teixeira, Maria J.; Perkey, David W.

    2003-08-01

    The sources and distribution of organic matter (OM) in surface waters and sediments from Winyah Bay (South Carolina, USA) were investigated using a variety of analytical techniques, including elemental, stable isotope and organic biomarker analyses. Several locations along the estuary salinity gradient were sampled during four different periods of contrasting river discharge and tidal range. The dissolved organic carbon (DOC) concentrations of surface waters ranged from 7 mg l -1 in the lower bay stations closest to the ocean to 20 mg l -1 in the river and upper bay samples. There was a general linear relationship between DOC concentrations and salinity in three of the four sampling periods. In contrast, particulate organic carbon (POC) concentrations were significantly lower (0.1-3 mg l -1) and showed no relationship with salinity. The high molecular weight dissolved OM (HMW DOM) isolated from selected water samples collected along the bay displayed atomic carbon:nitrogen ratios ([C/N]a) and stable carbon isotopic compositions of organic carbon ( δ13C OC) that ranged from 10 to 30 and from -28 to -25‰, respectively. Combined, such compositions indicate that in most HMW DOM samples, the majority of the OM originates from terrigenous sources, with smaller contributions from riverine and estuarine phytoplankton. In contrast, the [C/N]a ratios of particulate OM (POM) samples varied significantly among the collection periods, ranging from low values of ˜5 to high values of >20. Overall, the trends in [C/N]a ratios indicated that algal sources of POM were most important during the early and late summer, whereas terrigenous sources dominated in the winter and early spring. In Winyah Bay bottom sediments, the concentrations of the mineral-associated OM were positively correlated with sediment surface area. The [C/N]a ratios and δ13C OC compositions of the bulk sedimentary OM ranged from 5 to 45 and from -28 to -23‰, respectively. These compositions were consistent

  13. Behavior of dissolved aluminum in the Huanghe (Yellow River) and its estuary: Impact of human activities and sorption processes

    NASA Astrophysics Data System (ADS)

    Wang, Zhao-Wei; Ren, Jing-Ling; Zhang, Gui-Ling; Liu, Su-Mei; Zhang, Xiang-Zhao; Liu, Zhe; Zhang, Jing

    2015-02-01

    Dissolved aluminum (Al) is a sensitive tracer for biogeochemical cycles in the ocean. There has been a dramatic decline in water and sediment fluxes into the sea from the Huanghe because of climate change and human activities. Water-Sediment Regulation Schemes (WSRSs) have been implemented annually to flush trapped sediments from the upstream watercourse and reservoirs of the river. Monthly observations to investigate the behavior of dissolved Al in the lower reach of the Huanghe were carried out from November 2008 to December 2010. During 2009, daily observations were made to assess the impact of the ninth WSRS on the lower reach of the Huanghe and three cruises were carried out in the Huanghe Estuary in 2009 (prior to, during and following the WSRS). The monthly concentrations of dissolved Al ranged from 25 nM to 362 nM (average 90 nM) in the lower reach of the Huanghe. Assessment of the seasonal variation of dissolved Al showed that the highest concentrations occurred in summer and the lowest in winter: these corresponded to the variations in water discharge and sediment loads, which were controlled by WSRS events. During the ninth WSRS events in 2009 the daily runoff and sediment load increased from 200 m3/s to 3600 m3/s and from 0.1 g/L to 5 g/L, respectively. The concentration of dissolved Al increased from 180 nM to 600 nM (average 380 nM) in less than 20 days, which were equivalent to 43% of the annual Al flux into the Bohai. Exchange between dissolved and particulate Al, investigated using a simple sorption model based on the distribution coefficient (Kd), was approximately 106 mL/g in the Huanghe. The average concentrations of dissolved Al in the Huanghe Estuary prior to, during and following the WSRS were 243 nM, 238 nM and 186 nM, respectively. The comparable concentrations of dissolved Al in the Huanghe Estuary prior to and during the WSRS indicate that removal processes occurred in the initial stages of mixing in the estuary. The Al

  14. Study on seasonal variety of ocean color and delimitation between river and sea in Yellow River Estuary based on TM images

    NASA Astrophysics Data System (ADS)

    Ma, Anqing; Wang, Qixiang; Chen, Shang; Jia, Yonggang; Gao, Zhenghui

    2006-12-01

    Using Landsat-5 TM image on November 24, 2004 and May 13, 2005; and quasi-synchronous surveyed data, the dynamic change of suspended silt and chlorophyll a in the Yellow River Estuary were inversed and the coastal line of this region was interpreted. The mean correlation coefficient between measured data and spectral signature value of every image is 0.85 which proved that the inversion is satisfying. The results show that there were different seasonal patterns between suspended silt and chlorophyll a. The concentration of suspended silt in the surface seawater in the estuary averaged 307.8mg/L in winter and 352.7mg/L in spring. While the Chlorophyll a concentration in the surface seawater averaged 0.71μg/L in winter and 0.59μg/L in spring. The surveyed data show one distinct boundary in concentration of suspended silt along the sampled stations. The reversed data from band1, band2, band3, band4 and band6 also show the same boundary at the same location. The results of interpreting coastal line show that there is a rapid alteration in the Yellow River Estuary coastal line. Although in low or median water level period, with advance extent of the coastal line, there were prominent on the south shore beside the Laizhou Bay than the other places. Integrated with the practical measured data, by means of RS method, the study can get the same conclusion as the other methods did on judging boundary sign between River and Sea. So it also can be regarded as an efficient method to confirm boundary of River and Sea, and be the most available way to study dynamic state of coastal line of river mouth.

  15. Historical trends of hypoxia in Changjiang River estuary: Applications of chemical biomarkers and microfossils

    NASA Astrophysics Data System (ADS)

    Li, Xinxin; Bianchi, Thomas S.; Yang, Zuosheng; Osterman, Lisa E.; Allison, Mead A.; DiMarco, Steven F.; Yang, Guipeng

    2011-06-01

    Over the past two decades China has become the largest global consumer of fertilizers, which has enhanced river nutrient fluxes and caused eutrophication and hypoxia in the Yangtze (Changjiang) large river delta-front estuary (LDE). In this study, we utilized plant pigments, lignin-phenols, stable isotopes (δ 13C and δ 15N) and foraminiferal microfossils in 210Pb dated cores to examine the history of hypoxia in the Changjiang LDE. Two sediment cores were collected onboard R/V Dong Fang Hong 2 using a stainless-steel box-corer; one at a water depth of 24.7 m on Jun. 15, 2006 and the other at 52 m on Nov. 20, 2007, both in the hypoxic region off the Changjiang LDE. There has been a significant increase in the abundance of plant pigments after 1979 that are indicators of enhanced diatom and cyanobacterial abundance, which agrees with post-1980 record of increasing nutrient loads in the Changjiang River. The increased inputs of terrestrially derived materials to the LDE are largely woody plant sources and most likely due to deforestation that began in the early 1950s. However, post-1960 lignin data did not reflect enhanced loading of woody materials despite continued deforestation possibly due to increased trapping from greater dam construction, a reduction of deforestation in the drainage basin since the last 1990s, and soil conservation practices. The lack of linkages between bulk indices (stable isotopes, % OC, molar C/N ratios) and microfossil/chemical biomarkers may reflect relative differences in the amount of carbon tracked by these different proxies. Although NO 3- is likely responsible for most of the changes in phytoplankton production (post 1970s), historical changes in N loading from the watershed and hypoxia on the LDE shelf may not be as well linked in East China Sea (ECS) sediments due to possible denitrification/ammonification processes; finally, increases in low-oxygen tolerant foraminiferal microfossils indicate there has been an increase in the

  16. Historical trends of hypoxia in Changjiang River estuary: Applications of chemical biomarkers and microfossils

    USGS Publications Warehouse

    Li, X.; Bianchi, T.S.; Yang, Z.; Osterman, L.E.; Allison, M.A.; DiMarco, S.F.; Yang, G.

    2011-01-01

    Over the past two decades China has become the largest global consumer of fertilizers, which has enhanced river nutrient fluxes and caused eutrophication and hypoxia in the Yangtze (Changjiang) large river delta-front estuary (LDE). In this study, we utilized plant pigments, lignin-phenols, stable isotopes (δ13C and δ15N) and foraminiferal microfossils in 210Pb dated cores to examine the history of hypoxia in the Changjiang LDE. Two sediment cores were collected onboard R/V Dong Fang Hong 2 using a stainless-steel box-corer; one at a water depth of 24.7 m on Jun. 15, 2006 and the other at 52 m on Nov. 20, 2007, both in the hypoxic region off the Changjiang LDE. There has been a significant increase in the abundance of plant pigments after 1979 that are indicators of enhanced diatom and cyanobacterial abundance, which agrees with post-1980 record of increasing nutrient loads in the Changjiang River. The increased inputs of terrestrially derived materials to the LDE are largely woody plant sources and most likely due to deforestation that began in the early 1950s. However, post-1960 lignin data did not reflect enhanced loading of woody materials despite continued deforestation possibly due to increased trapping from greater dam construction, a reduction of deforestation in the drainage basin since the last 1990s, and soil conservation practices. The lack of linkages between bulk indices (stable isotopes, % OC, molar C/N ratios) and microfossil/chemical biomarkers may reflect relative differences in the amount of carbon tracked by these different proxies. Although NO3− is likely responsible for most of the changes in phytoplankton production (post 1970s), historical changes in N loading from the watershed and hypoxia on the LDE shelf may not be as well linked in East China Sea (ECS) sediments due to possible denitrification/ammonification processes; finally, increases in low-oxygen tolerant foraminiferal microfossils indicate there has been an increase in the

  17. Preliminary appraisal of ground water in and near the ancestral Missouri River Valley, northeastern Montana

    USGS Publications Warehouse

    Levings, G.W.

    1986-01-01

    A preliminary appraisal was conducted in and near the ancestral Missouri River valley in northeastern Montana to describe the groundwater resources and to establish a data base for the area. The data base then could be used for future evaluation of possible changes in water levels or water quality. In this area, consolidated aquifers are the Upper Cretaceous Fox Hills-lower Hell Creek aquifer and the overlying Paleocene Fort Union Formation. Unconsolidated aquifers are Pleistocene terrace gravel and glacial deposits and Holocene alluvial deposits. Aquifers are recharged by precipitation, infiltration of streamflow, and possibly leakage from lakes and potholes. Groundwater moves from topographically higher areas to the ancestral valley, then along the ancestral valley to the southwest. Water is discharged from aquifers by evapotranspiration, springs and seeps, movement directly into streams and lakes, and from pumping wells. Average well yields are greatest for irrigation wells completed in outwash gravel (886 gallons/min). Eighteen wells were completed in various aquifers to monitor potential long-term changes in water levels and water quality. Measured water levels declined about 2 ft. or less during the study (1982-85). Chemical analysis of groundwater samples indicated that concentrations of some dissolved constituents exceeded U.S. Environmental Protection Agency standards for drinking water. (USGS)

  18. Change in Land Cover along the Lower Columbia River Estuary as Determined from Landsat Thematic Mapper (TM) Imagery, Technical Report 2003.

    SciTech Connect

    Garono, Ralph; Anderson, Becci; Robinson, Rob

    2003-10-01

    The Lower Columbia River Estuary Management Plan (Jerrick, 1991) recognizes the positive relationship between the conservation of fish and wildlife habitat, and sustaining their populations. An important component of fish and wildlife conservation and management is the identification of habitats, trends in habitat change, and delineation of habitat for preservation, restoration or enhancement. Alterations to the environment, such as hydropower generation, dredging, forestry, agriculture, channel alteration, diking, bank stabilization and floodplain development, have dramatically altered both the type and distribution of habitats along the Columbia River Estuary (CRE) and its floodplain. Along the Columbia River, tidally influenced habitats occur from the river mouth to the Bonneville Dam, a distance of 230 km. If we are to effectively manage the natural resources of the Columbia River ecosystem, there is a need to understand how habitats have changed because fish and wildlife populations are known to respond to changes in habitat quality and distribution. The goal of this study was to measure the amount and type of change of CRE land cover from 1992 to 2000. We performed a change analysis on two spatial data sets describing land cover along the lower portion of the estuary (Fig. 1). The 1992 data set was created by the NOAA Coastal Remote Sensing, Coastal Change Analysis Program (C-CAP) in cooperation with Columbia River Estuary Study Task Force (CREST), the National Marine Fisheries Service (NMFS) Point Adams Field Station, and State of Washington Department of Natural Resources (DNR). The 2000 data set was produced by Earth Design Consultants, Inc. (EDC) and the Wetland Ecosystem Team (WET: University of Washington) as part of a larger Lower Columbia River Estuary Partnership (Estuary Partnership) habitat mapping study. Although the image classification methodologies used to create the data sets differed, both data sets were produced by classifying Landsat

  19. Water Temperature, Specific Conductance, pH, and Dissolved-Oxygen Concentrations in the Lower White River and the Puyallup River Estuary, Washington, August-October 2002

    USGS Publications Warehouse

    Ebbert, James C.

    2003-01-01

    The U.S. Geological Survey, Washington State Department of Ecology, and Puyallup Tribe of Indians monitored water temperature, specific conductance, pH, and dissolved-oxygen concentrations in the White River at river miles 4.9 and 1.8 from August until mid-October 2002. Water diverted from the White River upstream from the monitoring sites into Lake Tapps is returned to the river at river mile 3.6 between the two sites. The same characteristics were measured in a cross section of the Puyallup River estuary at river mile 1.5 during high and low tides in September 2002. In late August, maximum daily water temperatures in the White River of 21.1oC (degrees Celsius) at river mile 4.9 and 19.6oC at river mile 1.8 exceeded the water-quality standard of 18oC at both monitoring sites. In mid-September, maximum daily water temperatures at river mile 4.9 exceeded the standard on 5 days. From August 2-25, water temperatures at both monitoring sites were similar and little or no water was discharged from Lake Tapps to the White River. Increases in water temperature at river mile 1.8 in late September and early October were caused by the mixing of warmer water discharged from Lake Tapps with cooler water in the White River. Specific conductance in the White River usually was lower at river mile 1.8 than at river mile 4.9 because of mixing with water from Lake Tapps, which has a lower specific conductance. Maximum values of pH in the White River at river mile 4.9 often exceeded the upper limit of the water-quality standard, 8.5 pH units, from early September until mid-October, when turbidity decreased. The pH standard was not exceeded at river mile 1.8. Dissolved-oxygen concentrations in the White River were often lower at river mile 1.8 than at river mile 4.9 because of mixing with water discharged from Lake Tapps, which has lower dissolved-oxygen concentrations. The lowest concentration of dissolved oxygen observed was 7.9 mg/L (milligrams per liter) at river mile 1.8. The

  20. Waterbird Population Changes in the Wetlands at Chongming Dongtan in the Yangtze River Estuary, China

    NASA Astrophysics Data System (ADS)

    Ma, Zhijun; Wang, Yong; Gan, Xiaojing; Li, Bo; Cai, Yinting; Chen, Jiakuan

    2009-06-01

    We studied the changes in wetland habitats and waterbird communities between the 1980s and the 2000s at Chongming Dongtan, a Ramsar site in the Yangtze River estuary, an ecologically important region. This region is an important stopover site for shorebirds along the East Asian-Australasian flyway and is extensively used by waterfowl. A net loss of 11% of the wetland area was estimated during study periods at Chongming Dongtan. The change was dependent on wetland types: while the area of artificial habitats such as paddy fields and aquacultural ponds more than doubled, more than 65% of natural habitats including sea bulrush ( Scirpus mariqueter) and common reed ( Phragmites australis) marshes were lost over the two decades. An exotic plant species introduced from North America, smooth cordgrass ( Spartina alterniflora), occupied 30% of the vegetated intertidal zone by the 2000s. Although waterbird species richness did not change between the 1980s (110) and the 2000s (111), 13 species found in 1980s were replaced by 14 newly recorded species. Moreover, there were more species with declining trends (58) than with increasing trends (19). The population trends of species were affected by residential status and habitat types. Transients, wintering migrants, and habitat specialists were more likely to show declining trends compared to those breeding at Dongtan (including year-round and summer residents) and habitat generalists. Furthermore, species associated mainly with natural wetlands were more likely to decline than those associated mainly with artificial wetlands. These patterns suggest that the loss and change of wetland habitats at Chongming Dongtan adversely affected local population dynamics and might have contributed to the global decline of some waterbird species. Because Chongming Dongtan provides stopover and wintering habitats for many migratory waterbirds, protection and restoration of natural wetlands at Chongming Dongtan are urgently needed.

  1. [Abundance and biomass of meiobenthos in Lingdingyang Bay of Pearl River Estuary].

    PubMed

    Zhang, Jing-huai; Gao, Yang; Fang, Hong-da

    2011-10-01

    An investigation was conducted on the meiobenthic abundance and biomass in the Lingdingyang Bay of Pearl River Estuary in July-August 2006 (summer), April 2007 (spring), and October 2007 (autumn). A total of 15 meiobenthic groups were recorded, including Nematoda, Copepoda, Polychaeta, Ostracoda, Kinorhyncha, Amphipoda, Cumacea, Tanaidacea, Gnathostomulida, Nemertea, Gastropoda, Bivalvia, Sipuncula, Echiura, and other unidentified taxa. The average abundance of the meiobenthos in spring, summer, and autumn was 272.1 +/- 281.9, 165.1 +/- 147.1 and 246. 4 +/- 369.3 ind 10 cm(-2), and Nematoda was the most dominant group in abundance, accounting for 86.8%, 83.5%, and 93.4% of the total, respectively, followed by Polychaeta, and benthic Copepoda. The meiobenthic abundance had an uneven vertical distribution. 54.1% of the meibenthos were in 0-2 cm sediments, 35.2% were in 2-5 cm sediments, and 10.8% were in 5-10 cm sediments. 87.4% of nematodes were distributed in 0-5 cm sediments. The average biomass of the meiobenthos in spring, summer, and autumn was 374.6 +/- 346.9, 274.1 +/- 352.2, and 270.8 +/- 396.0 microg 10 cm(-2), and Polychaeta was the most dominant group in biomass, accounting for 30.1%, 46.7% and 46.0%, respectively, followed by Nematoda (25.2%, 20.1%, and 34.0%), and Ostracoda (20.6%, 15.3%, and 14.8%). The horizontal distribution of the meiobenthos had a trend of increasing from north to south, and being higher at east than at west. The meiobenthic abundance and biomass had significant positive correlations with water depth. PMID:22263483

  2. Osprey: worldwide sentinel species for assessing and monitoring environmental contamination in rivers, lakes, reservoirs, and estuaries.

    PubMed

    Grove, Robert A; Henny, Charles J; Kaiser, James L

    2009-01-01

    In the United States, many fish and wildlife species have been used nationwide to monitor environmental contaminant exposure and effects, including carcasses of the bald eagle (Haliaeetus leucocephalus), the only top avian predator regularly used in the past. Unfortunately, bald eagles are sensitive to investigator intrusion at the nest. Thus, the osprey (Pandion haliaetus) is evaluated as a potential sentinel species for aquatic ecosystems. Several characteristics support the choice of the osprey as a sentinel species, including: (1) fish-eating diet atop the aquatic food web, (2) long-lived with strong nest fidelity, (3) adapts to human landscapes (potentially the most contaminated), (4) tolerates short-term nest disturbance, (5) nests spatially distributed at regular intervals, (6) highly visible nests easily located for study, (7) ability to accumulate most, if not all, lipophilic contaminants, (8) known sensitivity to many contaminants, and (9) nearly a worldwide distribution. These osprey traits have been instrumental in successfully using the species to understand population distribution, abundance, and changes over time; the effects of various contaminants on reproductive success; how contaminants in prey (fish on biomass basis) contribute to egg concentrations (i.e., biomagnification factors); and spatial residue patterns. Data summarized include nesting population surveys, detailed nesting studies, and chemical analyses of osprey egg, organ, blood, and feather samples for contaminants that bioaccumulate and/or biomagnify in aquatic food webs; and biochemical evaluations of blood and various organs. Studies in the United States, Canada, Mexico, Europe, and elsewhere have shown the osprey to be a useful sentinel species for monitoring selected environmental contaminants, including some emerging contaminants in lakes, reservoirs, rivers, and estuaries. PMID:19117208

  3. An experimental study on major element release from the sediments in the Changjiang (Yangtze River) Estuary

    NASA Astrophysics Data System (ADS)

    Guo, Yanwei; Yang, Shouye

    2015-06-01

    With the enhanced warming and acidification of global ocean, whether and to what extent the naturally-weathered fluvial sediment into the sea can release elements and thus influence the geochemical process and ecosystem of global ocean remain to be resolved. In this contribution, an experimental study was carried out to examine the release rates of major elements (Ca, K, Mg and Al) from the surface sediments in the Changjiang (Yangtze River) Estuary under the pH values of 4.0, 6.0 and 7.0. The two studied sediments consist primarily of quartz, plagioclase, calcite and clay minerals, with the BET (Brunauer, Emmett and Teller) surface areas of 61.7 m2 g-1 and 23.1 m2 g-1. Major elements of Ca, K, Mg and Al show different release rates under different solution pH values. With the decreasing solution pH, the release rates of Ca and K increase obviously, while the release rates of Mg and Al increase with the initial solution pH varying from 6.0 to 7.0. The different release rates of these elements are closely related to the original mineral composition of the sediments and the reaction kinetics. Based on the experimental observation, quartz and clay minerals that have low dissolution rates may dominate the major element release to the aqueous phase. This study reveals that the enhancing ocean acidification could cause considerable release of major elements from natural terrigenous sediments into the ambient marine environment, which has to be considered carefully in the future study on global change.

  4. Determination of metal partitioning in porewater extracted from the Seine River Estuary sediment (France).

    PubMed

    Ouddane, Baghdad; Abbasse, Ghiasse; Halwani, Jalal; Fischer, Jean Claude

    2004-04-01

    Total dissolved trace and major metals and their partitioning in porewater sediment have been investigated at two sites in the Seine River estuary (France). For this purpose, solid phase extraction (SPE) has been employed using specific chelating resins for the separation and preconcentration of organic and inorganic forms of studied metals under controlled (N2) inert atmosphere. In fact, the study is focused on the development of a method for sample collection and handling under inert atmosphere in order to avoid some potential artefacts of the extracted porewater, to preserve the samples from possible chemical oxidation changes and to determine metals partitioning between organic and inorganic forms. For this point, a separation and preconcentration method using two columns in series (chelamine and C18 columns) was used. The trace and major metals fixed on the two resins for all determinations were stripped by nitric acid (2 M) and analyzed by Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) and Zeeman Graphite Furnace Atomic Absorption Spectroscopy (ZGF-AAS). The relationship between the distribution of metals and physico-chemical parameters such as pH and Eh (redox potential) as a function of depth was discussed. Some tendency in the distributions and seasonal variability of these traces and major metals are improved. The concentrations for all studied metals decreased as a function of depth where iron and manganese were found at mg L(-1) levels and other metals were found at [micro sign]g L(-1) levels, as well as there were significant fractions of all metals (except of manganese) which were complexed by organic matter. The comparison of data for the major elements (Fe and Mn), obtained by direct determination (without preconcentration) and preconcentration, show a very good recovery. PMID:15054531

  5. [Litter decomposition and its main affecting factors in tidal marshes of Minjiang River Estuary, East China].

    PubMed

    Zhang, Lin-Hai; Zeng, Cong-Sheng; Zhang, Wen-Juan; Wang, Tian-E; Tong, Chuan

    2012-09-01

    By using litterbag method, this paper studied the decomposition of the leaf- and flower litters of two emergent macrophytes, native species Phragmites australis and invasive species Spartina alterniflora, and related affecting factors in the Minjiang River estuary of East China. In the decomposition process of the litters, the decay of standing litter (0-90 days) was an important period, and the loss rate of the flower- and leaf litters dry mass of P. australis and S. alterniflora was 15.0 +/- 3.5% and 13.3 +/- 1.1%, and 31.9 +/- 1.1% and 20.8 +/- 1.4%, respectively. During lodging decay period (91-210 days), the loss rate of the flower- and leaf litters dry mass of P. australis and S. alterniflora was 69.5 +/- 0.6% and 71.5 +/- 2.5%, and 76.8 +/- 1.9% and 67.5 +/- 2.1%, respectively. In standing decay period, the decomposition rate of the two plants litters was positively correlated with the litters C/N but negatively correlated to the litters N/P, and the litters P was an important factor limiting the litters decay. In lodging decay period, the effects of the litters C/N, C/P, and N/P decreased, while the environment factors (climate, soil moisture, soil acidity and salinity, and sediment properties) acted more important roles. The differences in the factors affecting the decay of the litters in different decomposition periods were mainly related to the micro-environment and tidal process for the two plant communities. PMID:23285995

  6. Occurrence and levels of polybrominated diphenyl ethers in surface sediments from the Yellow River Estuary, China.

    PubMed

    Yuan, Zijiao; Liu, Guijian; Lam, Michael Hon Wah; Liu, Houqi; Da, Chunnian

    2016-05-01

    A total of 21 surface sediments collected from the Yellow River Estuary, China were analyzed for 40 kinds of polybrominated diphenyl ethers (PBDEs) using gas chromatography-mass spectrometry (GC-MS). Their levels, spatial distribution, congener profiles and possible sources were investigated. Only ten congeners were detected in the sediments. The total concentrations of the lower brominated BDEs (∑PBDEslow, PBDEs excluding BDE 209) and BDE 209 ranged from 0.482 ng/g to 1.07 ng/g and 1.16-5.40 ng/g, with an average value of 0.690 and 2.79 ng/g, respectively, which were both at the low end of the global contamination level. The congener profiles were dominated by BDE 209, with the average value accounting for 79.2% of the total PBDEs in the sediment samples. Among the nine lower brominated BDE congeners, BDE 47, 99 and 183 had high abundances. Although the commercial Penta/Octa-BDE products have been banned in most countries, the residual commercial Penta/Octa/Deca-BDE products and the debromination of highly brominated BDE compounds such as BDE 209 were still found to be the possible sources for the trace level of PBDEs in the present study area. In spite of the gradual removal of the commercial PBDEs in the world, the present research results further suggested that scientific attention should not be reduced on the issue of environmental contamination caused by these outdated chemical compounds. PMID:26845362

  7. Stratified active archaeal communities in the sediments of Jiulong River estuary, China

    PubMed Central

    Li, Qianqian; Wang, Fengping; Chen, Zhiwei; Yin, Xijie; Xiao, Xiang

    2012-01-01

    Here the composition of total and active archaeal communities in a sediment core of Jiulong River estuary at Fujian Province, Southern China was reported. Profiles of CH4 and SO2−4 concentrations from the sediment core indicated the existence of a sulfate-methane transition zone (SMTZ) in which sulfate reduction-coupled anaerobic oxidation of methane (AOM) occurs. Accordingly, three sediment layers (16–18.5 cm, 71–73.5 cm, and 161–163.5 cm) from the 1.2 m sediment core were sectioned and named top, middle and bottom, respectively. Total DNA and RNA of each layer were extracted and used for clone libraries and sequence analysis of 16S rRNA genes, the reverse transcription (RT)-PCR products of 16S rRNA and methyl CoM reductase alpha subunit (mcrA) genes. Phylogenetic analysis indicated that archaeal communities of the three layers were dominated by the Miscellaneous Crenarchaeotal Group (MCG) whose ecological functions were still unknown. The MCG could be further divided into seven subgroups, named MCG-A, B, C, D, E, F, and G. MCG-A and MCG-G were the most active groups in the estuarine sediments. Known anaerobic methanotrophic archaea (ANMEs) were only found as minor components in these estuarine archaeal communities. This study, together with the studies of deep subsurface sediments, would be a very good start point to target and compare the specific active archaeal groups and their roles in the dark, deep subsurface sediment environments. PMID:22969752

  8. Species diversity and distribution for phytoplankton of the Pearl River estuary during rainy and dry seasons.

    PubMed

    Huang, Liangmin; Jian, Weijun; Song, Xingyu; Huang, Xiaoping; Liu, Sheng; Qian, Peiyuan; Yin, Kedong; Wu, Madeline

    2004-10-01

    Based on data collected at 31 stations and 1 continuous station in the Pearl River estuary during cruises of July 1999 (rainy season) and January 2001 (dry season), this study examined taxonomic composition, abundance, and spatial distribution of phytoplankton. Results indicated 130 species of phytoplankton in the samples from the rainy season, and 132 species in the dry season. Among them, in the rainy season, 82 species of diatom, 39 fresh-water and half-fresh-water species and 41 species of red tide organisms were found. Within these, there were 54 tropical and sub-tropical species, 47 cosmopolitan species and 17 temperate species. The abundance of phytoplankton in the rainy season was higher than that of the dry season, with an average of 6.3 x 10(5) cells x L(-1) and 1.4 x 10(5) cells x L(-1), respectively. Diversity index (H') and evenness (J) were 2.47 and 0.57 in the rainy season, and 2.01 and 0.54 in the dry season. The dominant phytoplankton species in the rainy season was Skeletonema costatum with an average of 2.8 x 10(5) cells x L(-1) and 45.0% of the total phytoplankton abundance. In the dry season, Eucampia zoodiacus became the key dominant species (5.9 x 10(4) cells x L(-1)) when it was 43.47% of the total phytoplankton abundance. Distribution of the dominant species varied with salinity of sea-water, and their amounts correlated negatively with nutrients and zooplankton. PMID:15476837

  9. Plutonium and radiocesium in the water column of the Hudson River estuary

    NASA Astrophysics Data System (ADS)

    Linsalata, P.; Simpson, H. J.; Olsen, C. R.; Cohen, N.; Trier, R. M.

    1985-12-01

    Isotopes of plutonium (Pu), cesium (Cs), and cobalt (Co) introduced into the Hudson River Estuary from fallout deposition, the erosion of fallout-contaminated surface soils, and nuclear reactor effluent (isotopes of Cs and Co only) have been measured in water column samples collected from 1975 to 1980 Isotopic measurements conducted independently by two research groups utilizing different sampling and analytical techniques have been summarized. The major conclusions drawn from the work are that for water samples collected by the two laboratories over similar time periods, the mean concentrations of nonfilterable239,240Pu (<0.45 μm) were identical at 0.13 fCi/l, mean concentrations of both137Cs and239,240Pu in suspended particulates were more divergent at 2,270±920 pCi/kg (±1 SD) and 1,430±430 pCi/kg for137Cs, and 19±8 pCi/kg and 12±4 pCi/kg for239,240Pu The behavior of239,240Pu and137Cs within the water column is shown to diverge within brackish waters Specifically, the magnitude of the137Cs distribution coefficient ( K d ) can be expressed as an inverse power function of the chloride ion concentrations for chlorinities between 0.1 and 4 g Cl-/l No difference in the239,240Pu K d has been observed between fresh and brackish waters Based on the expected inventories of239,240Pu and137Cs within watershed soils, the current downstream transport of these radionuclides represents fractional mobilization rates on the order of 1 4 (×10-4) per year

  10. Sediment transport in response to changes in river discharge and tidal mixing in a funnel-shaped micro-tidal estuary

    NASA Astrophysics Data System (ADS)

    Gong, Wenping; Jia, Liangwen; Shen, Jian; Liu, James T.

    2014-03-01

    Huangmaohai Estuary is a micro-tidal funnel-shaped estuary, located along the southwestern side of the Pearl River Delta complex. Variations of sediment transport patterns under different conditions of river discharge and tidal mixing are investigated by using field measurements and data analysis during both dry and wet seasons, respectively. The intratidal variation of sediment dynamics is largely controlled by the tidal asymmetry. The typical pattern of 25-hour mean sediment transport during the dry season is that the transport is landward in the channel and seaward on the shoals. A bifurcation pathway of sediment transport shows that sediments are imported from the East Opening and exported through the Middle Opening. However, this pattern can be altered by mixing processes and river discharge. Enhanced mixing or increased discharge can result in a predominantly seaward transport. Conversely, weak mixing can result in an emphatic landward transport. In general, the sediment transport is closely associated with the morphological evolution in the estuary.

  11. Distributions of Core- and Polar- Archaeal Lipids in the Lower Pearl River and Estuary: Implications for TEX86 Proxies

    NASA Astrophysics Data System (ADS)

    Wang, J.; Zhang, C.; Zhu, C.; Wei, Y.; Dong, H.; Liu, W.

    2011-12-01

    Core isoprenoidal glycerol dibiphytanyl dlycerol tetraethers (C-iGDGTs) are the most widespread archaeal lipids in sediments and water, and have been used to construct a molecular proxy, TEX86, for studying past sea surface temperatures. However, recent analyses of intact polar (IP)-iGDGTs that are indicative of living archaea suggest that IP-iGDGTs produced in situ in marine sediments may subsequently convert IP-iGDGTs to C-iGDGTs after the cell death, thus compromising the validity of TEX86 for paleoclimate research. To help address this question, we investigated the distribution and abundance of IP- and C- iGDGTs in suspended particulates and surface sediments from the lower Pearl River and estuary. Our results show a strong positive correlation between the C- and P-iGDGTs pools, especially the iGDGT-0 (R2 = 0.786, p<0.001), iGDGT-1 (R2 = 0.920, p<0.001), and crenarchaeol (R2 = 0.871, p<0.001), suggesting that aquatic archaeal lipids are mostly derived from in situ production in the river water and/or sediments, and a minor fraction of these lipids are terrestrially-sourced. Methanogens (belonging to Euryarchaeota) may be an important source of iGDGTs in water and sediments of Pearl River estuary, which may further complicate the use of TEX86 that is based on planktonic Crenarchaeota.

  12. Use of Reflectance Ratios as a Proxy for Coastal Water Constituent Monitoring in the Pearl River Estuary

    PubMed Central

    Fang, Li-Gang; Chen, Shui-Sen; Li, Dong; Li, Hong-Li

    2009-01-01

    Spectra, salinity, total suspended solids (TSS, in mg/L) and colored dissolved organic matter (CDOM, ag(400) at 400 nm) sampled in stations in 44 different locations on December 18, 19 and 21, in 2006 were measured and analyzed. The studied field covered a large variety of optically different waters, the absorption coefficient of CDOM ([ag(400)] in m-1) varied between 0.488 and 1.41 m-1, and the TSS concentrations (mg/L) varied between 7.0 and 241.1 mg/L. In order to detect salinity of the Pearl River Estuary, we analyzed the spectral properties of TSS and CDOM, and the relationships between field water reflectance spectra and water constituents' concentrations based on the synchronous in-situ and satellite hyper-spectral image analysis. A good correlation was discovered (the positive correlation by linear fit), between in-situ reflectance ratio R680/R527 and TSS concentrations (R2 = 0.65) for the salinity range of 1.74-22.12. However, the result also showed that the absorption coefficient of CDOM was not tightly correlated with reflectance. In addition, we also observed two significant relationships (R2 > 0.77), one between TSS concentrations and surface salinity and the other between the absorption coefficient of CDOM and surface salinity. Finally, we develop a novel method to understand surface salinity distribution of estuarine waters from the calibrated EO-1 Hyperion reflectance data in the Pearl River Estuary, i.e. channels with high salinity and shoals with low salinity. The EO-1 Hyperion derived surface salinity and TSS concentrations were validated using in-situ data that were collected on December 21, 2006, synchronous with EO-1 Hyperion satellite imagery acquisition. The results showed that the semi-empirical relationships are capable of predicting salinity from EO-1 Hyperion imagery in the Pearl River Estuary (RMSE < 2‰). PMID:22389623

  13. Dietary Studies on the Predatory Fishes of the Norman River Estuary, with Particular Reference to Penaeid Prawns

    NASA Astrophysics Data System (ADS)

    Salini, J. P.; Brewer, D. T.; Blaber, S. J. M.

    1998-06-01

    The predatory fish community and their prey in the Norman Rivere estuary, Gulf of Carpentaria Australia, are compared with the communities of other tropical inshore areas, to investigate patterns of predation in tropical inshore areas particularly in relation to penaeid prawns. Abiotic factors (turbidity, freshwater input) and diversity of habitat types affect the composition of both prey and predator communities, resulting in large differences in the communities of tropical inshore waters. The stomach contents of 2059 predatory fish from the Norman River estuary were analysed over four sampling trips in the wet and dry seasons. The stomachs of 61% (1255 fish) of 54 species contained a total of 676·2 g (dry weight) of food, while 39% (804 fish) were empty. Teleosts were the main component of the diet (by dry weight) of 13 of the 22 species analysed, followed by annelids for two species. Five species had only teleosts in their stomachs. Most predator species ate benthic or bentho-pelagic prey, while three species— Rhizoprionodon taylori, Scomberoides commersonianusand Leptobrama mulleri—ate mainly pelagic prey. Although 19 species ate some penaeids, only Polydactylus sheridaniate little else. This species, Lates calcariferand Eleutheronema tetradactylumate 94·5% of all the penaeid prey and 97·9% of all the commercially important penaeid prey recorded in the study. Penaeid predation indices (calculated from gillnet catch rates, proportion of penaeids in the diet and a consumption rate of 3% body weight per day) were 0·23 g of penaeid per net-metre per day for P. sheridani, 0·15 for L. calcariferand 0·03 for E. tetradactylum. Commercially important penaeid predation indices were 0·11, 0·13 and 0·01, respectively. These values are intermediate between those previously recorded for the main penaeid predators in other inshore areas of the Gulf of Carpentaria (Embley River estuary and Groote Eylandt).

  14. Tsunami hazard assessment in the Hudson River Estuary based on dynamic tsunami-tide simulations

    NASA Astrophysics Data System (ADS)

    Shelby, Michael; Grilli, Stéphan T.; Grilli, Annette R.

    2016-05-01

    This work is part of a tsunami inundation mapping activity carried out along the US East Coast since 2010, under the auspice of the National Tsunami Hazard Mitigation program (NTHMP). The US East Coast features two main estuaries with significant tidal forcing, which are bordered by numerous critical facilities (power plants, major harbors,...) as well as densely built low-level areas: Chesapeake Bay and the Hudson River Estuary (HRE). HRE is the object of this work, with specific focus on assessing tsunami hazard in Manhattan, the Hudson and East River areas. In the NTHMP work, inundation maps are computed as envelopes of maximum surface elevation along the coast and inland, by simulating the impact of selected probable maximum tsunamis (PMT) in the Atlantic ocean margin and basin. At present, such simulations assume a static reference level near shore equal to the local mean high water (MHW) level. Here, instead we simulate maximum inundation in the HRE resulting from dynamic interactions between the incident PMTs and a tide, which is calibrated to achieve MHW at its maximum level. To identify conditions leading to maximum tsunami inundation, each PMT is simulated for four different phases of the tide and results are compared to those obtained for a static reference level. We first separately simulate the tide and the three PMTs that were found to be most significant for the HRE. These are caused by: (1) a flank collapse of the Cumbre Vieja Volcano (CVV) in the Canary Islands (with a 80 km3 volume representing the most likely extreme scenario); (2) an M9 coseismic source in the Puerto Rico Trench (PRT); and (3) a large submarine mass failure (SMF) in the Hudson River canyon of parameters similar to the 165 km3 historical Currituck slide, which is used as a local proxy for the maximum possible SMF. Simulations are performed with the nonlinear and dispersive long wave model FUNWAVE-TVD, in a series of nested grids of increasing resolution towards the coast, by one

  15. Water quality of the tidal Potomac River and Estuary: Hydrologic Data Reports supplement, 1979 through 1981 water years

    SciTech Connect

    Coupe, R.H. Jr.; Webb, W.E.

    1984-01-01

    This report is a companion report to the US Geological Survey 1979, 1980, and 1981 Hydrologic Data Reports of the tidal Potomac River and Estuary. The information included in this report contains values of biochemical oxygen demand and specific-rate constants, incident-light and light-attenuation measurements; numbers of phytoplankton, fecal coliform and fecal streptococci; cross-sectional averages from field measurements of dissolved oxygen, pH, specific conductance, and temperature data; and cross-sectional averages of chlorophyll data. Sewage-treatment plant loads are also included. 29 refs., 4 figs., 3 tabs.

  16. Nutrient fluxes in the Changjiang River estuary and adjacent waters — a modified box model approach

    NASA Astrophysics Data System (ADS)

    Wang, Xiaohong; Yu, Zhiming; Fan, Wei; Song, Xiuxian; Cao, Xihua; Yuan, Yongquan

    2015-01-01

    To solve nutrient flux and budget among waters with distinct salinity difference for water-salt-nutrient budget, a traditional method is to build a stoichiometrically linked steady state model. However, the traditional way cannot cope appropriately with those without distinct salinity difference that parallel to coastline or in a complex current system, as the results would be highly affected by box division in time and space, such as the Changjiang (Yangtze) River estuary (CRE) and adjacent waters (30.75°2-31.75°N, 122°10'-123°20'E). Therefore, we developed a hydrodynamic box model based on the traditional way and the regional oceanic modeling system model (ROMS). Using data from four cruises in 2005, horizontal, vertical and boundary nutrient fluxes were calculated in the hydrodynamic box model, in which flux fields and the major controlling factors were studied. Results show that the nutrient flux varied greatly in season and space. Water flux outweighs the nutrient concentration in horizontal flux, and upwelling flux outweighs upward diffusion flux in vertical direction (upwelling flux and upward diffusion flux regions overlap largely all the year). Vertical flux in spring and summer are much greater than that in autumn and winter. The maximum vertical flux for DIP (dissolved inorganic phosphate) occurs in summer. Additional to the fluxes of the Changjiang River discharge, coastal currents, the Taiwan Warm Current, and the upwelling, nutrient flux inflow from the southern Yellow Sea and outflow southward are found crucial to nutrient budgets of the study area. Horizontal nutrient flux is controlled by physical dilution and confined to coastal waters with a little into the open seas. The study area acts as a conveyer transferring nutrients from the Yellow Sea to the East China Sea in the whole year. In addition, vertical nutrient flux in spring and summer is a main source of DIP. Therefore, the hydrodynamic ROMS-based box model is superior to the traditional

  17. Zooplankton spatial and diurnal variations in the Changjiang River estuary before operation of the Three Gorges Dam

    NASA Astrophysics Data System (ADS)

    Gao, Xuelu; Song, Jinming; Li, Xuegang

    2011-05-01

    Estuarine plankton communities can serve as indicators of ecosystem modification in response to anthropogenic influences. The main objectives of this study were to describe the spatial distribution and diurnal variability in zooplankton abundance and biomass over almost entire salinity gradient of the Changjiang (Yangtze) River estuary and to provide a background reference for future studies. To accomplish this, data were collected from 29 stations in the estuary from May 19 to 26, 2003, including two anchor stations. The spatial and diurnal variations in zooplankton characteristics, i.e. abundance, biomass, and gross taxonomic composition, were examined. Generally, both the abundance and biomass gradually increased seaward and presented distinct spatial variations. In addition, the spatial data revealed a significant correlation between abundance and biomass; however, there was no significant correlation between abundance and biomass for the diurnal data. Although the zooplankton composition indicated distinct spatial differences in terms of dominant groups, copepods accounted for >50% of the total zooplankton abundance in most regions and times. Three zooplankton assemblages were recognized through hierarchical cluster analysis. These assemblages existed along the salinity gradient from fresh water to seawater, and their positions coincided with those of the three principal water masses in the estuary. The assemblages were classified as: (1) true estuarine, (2) estuarine and marine, and (3) euryhaline marine, which were characterized by the copepods Sinocalanus dorrii, Labidocera euchaeta, and Calanus sinicus, respectively. Both spatial and diurnal data indicated that there was no significant correlation between zooplankton abundance/biomass and depth-integrated phytoplankton abundance.

  18. Distribution of submerged aquatic vegetation in the St. Louis River estuary: Maps and models (Presentation)

    EPA Science Inventory

    SAV provides the biophysical basis for several ecosystem services in Great Lakes estuaries including rearing and adult habitat for commercially and recreationally important fishes, foraging habit for waterfowl, and nutrient retention. Understanding sources of variation in SAV in ...

  19. 2004 AND 2006 COHO SMOLT MOVEMENT IN THE YAQUINA RIVER AND ESTUARY

    EPA Science Inventory

    Migratory fish passage is an important designated use for many Oregon estuaries. Acoustic transmitters were implanted in coho smolts in 2004 and 2006 to evaluate how estuarine habitat, and habitat loss, might affect population health. Acoustic receivers that identified individu...

  20. Infilling of the Hudson River Estuary During the Late Holocene (3000ka to Present): Implications for Estuarine Stratigraphic Models

    NASA Astrophysics Data System (ADS)

    McHugh, C. M.; Pekar, S. F.; Ryan, W. B.; Carbotte, S.; Bell, R.; Burckle, L.

    2002-12-01

    Estuaries are widely preserved in the geologic record and the estuarine fill, contained between non-marine sediment, provides an excellent temporal marker for continental margin studies. Estuarine stratigraphic models have provided a framework within which to interpret the estuarine fill. However, estuarine systems differ greatly in the shape of their valleys, the tectonic boundaries they cross, and in sediment supply so that their position in the geologic record may be out of sequence with that predicted by the models. New insights into estuarine systems and models are provided by the Hudson River Estuary (HRE; New York State) based on >150 cores and grab sediment samples and acoustic images documenting in great detail how the HRE filled its earlier excavated valley during the latest Holocene (3ka to present). Radiocarbon and 137-Cs radioisotope ages, borehole, and core data document the sedimentation patterns of the estuary. Diatom assemblages provide estimates of the shallowing-upwards of the estuary as its basin filled with sediments. The three areas of the stratigraphic model present in the HRE, include zones formed within inner fluvial and outer marine areas, (containing coarse-grained, sands and gravels), and a central area (containing fine-grained, silts and clays), that are nearly filled with little room for sediments to accumulate at or near sea-level. This has resulted in sedimentary bypass for almost the entire length the estuary. South of Kingston, fine-grained sediments have ceased accumulating when the bottom approaches wave base. Upstream from Kingston, final filling occurs as sediments fill in the remaining accommodation, forming islands. This should result in the export of sediment to the coastal zone. Instead, localized areas of sediment trapping still exist, which are related to the Hudson Valley Highlands and to the location of the estuarine turbidity maximum that hold large volumes of sediment. As a result minor volumes of Recent sediment are

  1. CO2 flux and seasonal variability in the turbidity maximum zone and surrounding area in the Changjiang River estuary

    NASA Astrophysics Data System (ADS)

    Li, Xuegang; Song, Jinming; Yuan, Huamao; Li, Ning; Duan, Liqin; Qu, Baoxiao

    2015-01-01

    The turbidity maximum zone (TMZ) is one of the most important regions in an estuary. However, the high concentration of suspended material makes it difficult to measure the partial pressure of CO2 ( pCO2) in these regions. Therefore, very little data is available on the pCO2 levels in TMZs. To relatively accurately evaluate the CO2 flux in an example estuary, we studied the TMZ and surrounding area in the Changjiang (Yangtze) River estuary. From seasonal cruises during February, August, November 2010, and May 2012, the pCO2 in the TMZ and surrounding area was calculated from pH and total alkalinity (TA) measured in situ, from which the CO2 flux was calculated. Overall, the TMZ and surrounding area acted as a source of atmosphere CO2 in February and November, and as a sink in May and August. The average FCO2 was -9, -16, 5, and 5 mmol/(m2·d) in May, August, November, and February, respectively. The TMZ's role as a source or sink of atmosphere CO2 was quite different to the outer estuary. In the TMZ and surrounding area, suspended matter, phytoplankton, and pH were the main factors controlling the FCO2, but here the influence of temperature, salinity, and total alkalinity on the FCO2 was weak. Organic carbon decomposition in suspended matter was the main reason for the region acting as a CO2 source in winter, and phytoplankton production was the main reason the region was a CO2 sink in summer.

  2. Learning Lessons from Estuaries

    ERIC Educational Resources Information Center

    Schnittka, Christine

    2006-01-01

    There is something that draws all people to the sea and especially to the fertile estuaries that nuzzle up to its shores. An estuary serves as both a nursery and a grave for sea creatures. If life evolved from some primordial sea, it may well have been an estuary--a place where ocean and rivers meet and fresh and salty waters mingle in the…

  3. Perfluorooctane sulfonate (PFOS) distribution and effect factors in the water and sediment of the Yellow River Estuary, China.

    PubMed

    Wang, Shiliang; Wang, Hui; Deng, Wenjing

    2013-10-01

    The distribution of perfluorooctane sulfonate (PFOS) was investigated in a total of 15 water and sediment samples from the Yellow River Estuary, China in April 2011. The results indicated that the concentrations of PFOS in the water and sediment samples averaged 157.5 ng/L and 198.8 ng/g and ranged from 82.30 to 261.8 ng/L and 75.48 to 457.0 ng/g, respectively. The concentrations of PFOS in the sediment column increased from 45.32 to 379.98 ng/g with the decrease of the sampling depth, which showed that the increased PFOS pollution in the sediment appeared in this region in over recent years. The distribution coefficient (K d) of PFOS between water and sediment linearly increased from 0.37 to 4.80 L/g as the salinity (S‰) increased from 0.18 to 4.47. Correlation analysis revealed that K d was significantly and positively correlated to the contents of total organic carbon and clay of the sediment, and salinity. Therefore, salinity was an important parameter in controlling the sediment-water interactions and the fate or transport of PFOS in the aquatic environment. The results of this study showed that the estuary was an important sink for PFOS and suggested that PFOS might be carried with the river water and transported for long distances before it reached to the sea and largely scavenged to the sediment in the estuaries due to the change in salinity. PMID:23591678

  4. Evaluating Cumulative Ecosystem Response to Restoration Projects in the Columbia River Estuary, Annual Report 2004

    SciTech Connect

    Diefenderfer, Heida L.; Roegner, Curtis; Thom, Ronald M.; Dawley, Earl M.; Whiting, Allan H.; Johnson, Gary E.; Sobocinski, Kathryn L.; Anderson, Michael G.; Ebberts, Blaine

    2005-12-15

    indicators for detecting a signal in the estuarine system resulting from the multiple projects were also reviewed, i.e. organic matter production, nutrient cycling, sedimentation, food webs, biodiversity, salmon habitat usage, habitat opportunity, and allometry. In subsequent work, this information will be used to calculate the over net effect on the ecosystem. To evaluate the effectiveness of habitat restoration actions in the lower Columbia River and estuary, a priority of this study has been to develop a set of minimum ecosystem monitoring protocols based on metrics important for the CRE. The metrics include a suite of physical measurements designed to evaluate changes in hydrological and topographic features, as well as biological metrics that will quantify vegetation and fish community structure. These basic measurements, intended to be conducted at all restoration sites in the CRE, will be used to (1) evaluate the effectiveness of various restoration procedures on target metrics, and (2) provide the data to determine the cumulative effects of many restoration projects on the overall system. A protocol manual is being developed for managers, professional researchers, and informed volunteers, and is intended to be a practical technical guide for the design and implementation of monitoring for the effects of restoration activities. The guidelines are intended to standardize the collection of data critical for analyzing the anticipated ecological change resulting from restoration treatments. Field studies in 2005 are planned to initiate the testing and evaluation of these monitoring metrics and protocols and initiate the evaluation of higher order metrics for cumulative effects.

  5. Spatio-temporal distributions of chlorofluorocarbons and methyl iodide in the Changjiang (Yangtze River) estuary and its adjacent marine area.

    PubMed

    Yuan, Da; Yang, Gui-Peng; He, Zhen

    2016-02-15

    Temporal and spatial distribution patterns of volatile halogenated organic compounds (VHOCs), such as dichlorodifluoromethane (CFC-12), trichlorofluoromethane (CFC-11), trichlorotrifluoroethane (CFC-113), and methyl iodide (CH3I), in the Changjiang (Yangtze River) estuary and its adjacent marine area were measured during two cruises from 21 February to 10 March 2014 and from 10 to 21 July 2014. VHOC concentrations showed seasonal variation with higher values during winter. VHOC distributions evidently decreased along the freshwater plume from the river mouth to the open sea and from inshore to offshore regions. VHOC distributions were obviously influenced by the Changjiang runoff, anthropogenic inputs, and biological release of phytoplankton. The study area was a net sink for CFC-12 and CFC-11, but a net source for atmospheric CH3I during the study periods. PMID:26707981

  6. Collection and analysis of remotely sensed data from the Rhode River Estuary Watershed. [ecological parameters of Chesapeake Bay

    NASA Technical Reports Server (NTRS)

    Jenkins, D. W.

    1972-01-01

    NASA chose the watershed of Rhode River, a small sub-estuary of the Bay, as a representative test area for intensive studies of remote sensing, the results of which could be extrapolated to other estuarine watersheds around the Bay. A broad program of ecological research was already underway within the watershed, conducted by the Smithsonian Institution's Chesapeake Bay Center for Environmental Studies (CBCES) and cooperating universities. This research program offered a unique opportunity to explore potential applications for remote sensing techniques. This led to a joint NASA-CBCES project with two basic objectives: to evaluate remote sensing data for the interpretation of ecological parameters, and to provide essential data for ongoing research at the CBCES. A third objective, dependent upon realization of the first two, was to extrapolate photointerpretive expertise gained at the Rhode River watershed to other portions of the Chesapeake Bay.

  7. A Synthesis of Environmental and Plant Community Data for Tidal Wetland Restoration Planning in the Lower Columbia River and Estuary

    SciTech Connect

    Diefenderfer, Heida L.; Borde, Amy B.; Cullinan, Valerie I.

    2013-12-01

    This report reanalyzes and synthesizes previously existing environmental and plant community data collected by PNNL at 55 tidal wetlands and 3 newly restored sites in the lower Columbia River and estuary (LCRE) between 2005 and 2011. Whereas data were originally collected for various research or monitoring objectives of five studies, the intent of this report is to provide only information that will have direct utility in planning tidal wetland restoration projects. Therefore, for this report, all tidal wetland data on plants and the physical environment, which were originally developed and reported by separate studies, were tabulated and reanalyzed as a whole. The geographic scope of the data collected in this report is from Bonneville Lock and Dam to the mouth of the Columbia River

  8. Temporal trends of hydrocarbons in sediment cores from the Pearl River Estuary and the northern South China Sea.

    PubMed

    Peng, Xianzhi; Wang, Zhendi; Yu, Yiyi; Tang, Caiming; Lu, Hong; Xu, Shiping; Chen, Fanrong; Mai, Bixian; Chen, Shejun; Li, Kechang; Yang, Chun

    2008-11-01

    Concentrations and fluxes of unresolved complex mixture of hydrocarbons (UCM) and polycyclic aromatic hydrocarbons (PAHs) were analyzed for two (210)Pb dated sediment cores from the Pearl River Estuary (PRE) and the adjacent northern South China Sea (NSCS). Compound-specific stable carbon isotopic compositions of individual n-alkanes were also measured for identification of the hydrocarbon sources. The historical records of PAHs in the NSCS reflected the economic development in the Pearl River Delta during the 20th century. PAHs in the NSCS predominantly derive from combustion of coal and biomass, whereas PAHs in the PRE are a mixture of petrogenic and pyrogenic in origins. The isotopic profiles reveal that the petrogenic hydrocarbons in the PRE originate predominantly from local spillage/leakage of lube oil and crude oils. The accumulation rates of pyrogenic PAHs have significantly increased, whereas UCM accumulation has slightly declined in the NSCS in the recent three decades. PMID:18339464

  9. An experimental transplantation to select the optimal site for restoration of the eelgrass Zostera marina in the Taehwa River estuary

    NASA Astrophysics Data System (ADS)

    Park, Jung-Im; Kim, Jeong Bae; Lee, Kun-Seop; Son, Min Ho

    2013-12-01

    To select the optimal site for the restoration of seagrass habitats in the Taehwa River estuary, we transplanted the eelgrass Zostera marina to three potential candidate sites in March 2007 and monitored the transplanted seagrass and associated environmental factors for six months. In all three sites, the transplanted seagrasses exhibited no initial morphological loss due to transplanting stress. The transplanted seagrass communities at sites 2 and 3 showed more than a 180% increase in density over the entire survey period. In contrast, despite a density increase in the first month after transplantation, most of the transplanted seagrasses at site 1 died. This may be due to the large decrease in underwater irradiance reaching the seagrass leaves at site 1 for two months during June and July, which fell below the level of compensation irradiance. The growth rate and size of the seagrass shoots were also larger at sites 2 and 3 compared with site 1. This is probably due to higher nutrient concentrations in the sediment pore water at sites 2 and 3 compared with site 1, although water depth, salinity, and the nutrient concentrations in the water columns from the three sites were similar. Therefore, for the restoration of seagrass habitats in the Taehwa River estuary, sites 2 and 3 were preferable to site 1 as transplantation sites.

  10. Temporal and spatial distribution of red tide outbreaks in the Yangtze River Estuary and adjacent waters, China.

    PubMed

    Liu, Lusan; Zhou, Juan; Zheng, Binghui; Cai, Wenqian; Lin, Kuixuan; Tang, Jingliang

    2013-07-15

    Between 1972 and 2009, evidence of red tide outbreaks in the Yangtze River Estuary and adjacent waters was collected. A geographic information system (GIS) was used to analyze the temporal and spatial distribution of these red tides, and it was subsequently used to map the distribution of these events. The results show that the following findings. (1) There were three red tide-prone areas: outside the Yangtze River Estuary and the eastern coast of Sheshan, the Huaniaoshan-Shengshan-Gouqi waters, and the Zhoushan areas and eastern coast of Zhujiajian. In these areas, red tides occurred 174 total times, 25 of which were larger than 1000 km(2) in areal extent. After 2000, the frequency of red tide outbreaks increased significantly. (2) During the months of May and June, the red tide occurrence in these areas was 51% and 20%, respectively. (3) Outbreaks of the dominant red tide plankton species Prorocentrum dong-haiense, Skeletonema costatum, Prorocentrum dantatum, and Noctiluca scientillan occurred 38, 35, 15, and 10 times, respectively, during the study interval. PMID:23628547

  11. Accessing the Relationship between archaeal and bacterial Tetraethers in the Pearl River Estuary and Coastal South China Sea

    NASA Astrophysics Data System (ADS)

    Wang, J. X.

    2015-12-01

    Microbial intact polar GDGTs with phosphate head groups (phospho IP-GDGTs) are powerful biomarkers for tracing interactions between living cells and their environments. The goal of this study was to examine the relationship between archaeal isoprenoid (iso-) GDGTs and bacterial branched (br-) in the Pearl River estuary and coastal South China Sea. Suspended particulate matter (SPM) was collected using 0.7 μm- and 0.2 μm-filters in winter and summer of 2012. The results exhibited that 1) the abundance of phospho IP-isoGDGTs is lower than phospho IP-brGDGTs in different seasons, and 2) phospho IP-brGDGTs collected from 0.2 μm-filter in winter are significantly higher than the summer. Linear regression analysis showed that the abundance of phospho IP-isoGDGTs and phospho IP-brGDGTs are significantly correlated, suggesting that the source archaea of the isoGDGTs may have functional relationship with the brGDGT-producing bacteria in the study area. Furthermore, the seasonal highest abundances of iso- and br-GDGTs always occurred in the transitional zone between river and estuary, indicating that the transitional area is a highly productive environment for the GDGT-producing organisms.

  12. Environmental monitoring and assessment of heavy metals in surface sediments at Coleroon River Estuary in Tamil Nadu, India.

    PubMed

    Venkatramanan, S; Chung, S Y; Ramkumar, T; Selvam, S

    2015-08-01

    The combined studies on grain size distribution, organic matter contents of sediments, sequential extraction and bulk concentration of heavy metals, statistical analysis, and ecological risk assessments were carried out to investigate the contamination sources and ecological risks of surface sediments at Coleroon River Estuary in Tamil Nadu, India. The sequential extraction of metals showed that a larger portion of the metals was associated with the residual phase and also in other fractions. The low concentrations of heavy metals were found in exchangeable and carbonate bounds (bioavailable phases). It revealed that sediments of Coleroon River Estuary were relatively unpolluted and were influenced mainly by natural sources. The observed order of bulk concentrations of heavy metals in the sediments was as follows: Fe > Mn > Zn > Cu > Pb > Cr > Ni > Co. Factor analyses represented that the enrichment of heavy metals was mostly resulted from lithogenic origins associated with anthropogenic sources. These sources were reconfirmed by cluster analysis. Risk assessment code (RAC) suggested that all metals were not harmful in monsoon season. However, Fe was in medium risk, and Mn and Cu were in low risk in summer. According to pollution load index (PLI) of sediments, all heavy metals were toxic. Cu might be related with adverse biological effects on the basis of sediment quality guidelines (SQG) in both seasons. These integrated approaches were very useful to identify the contamination sources and ecological risks of sediments in estuarine environment. It is expected that this research can give a useful information for the remediation of heavy metals in sediments. PMID:26178040

  13. Tsunami hazard assessment in the Hudson River Estuary based on dynamic tsunami-tide simulations

    NASA Astrophysics Data System (ADS)

    Shelby, Michael; Grilli, Stéphan T.; Grilli, Annette R.

    2016-05-01

    This work is part of a tsunami inundation mapping activity carried out along the US East Coast since 2010, under the auspice of the National Tsunami Hazard Mitigation program (NTHMP). The US East Coast features two main estuaries with significant tidal forcing, which are bordered by numerous critical facilities (power plants, major harbors,...) as well as densely built low-level areas: Chesapeake Bay and the Hudson River Estuary (HRE). HRE is the object of this work, with specific focus on assessing tsunami hazard in Manhattan, the Hudson and East River areas. In the NTHMP work, inundation maps are computed as envelopes of maximum surface elevation along the coast and inland, by simulating the impact of selected probable maximum tsunamis (PMT) in the Atlantic ocean margin and basin. At present, such simulations assume a static reference level near shore equal to the local mean high water (MHW) level. Here, instead we simulate maximum inundation in the HRE resulting from dynamic interactions between the incident PMTs and a tide, which is calibrated to achieve MHW at its maximum level. To identify conditions leading to maximum tsunami inundation, each PMT is simulated for four different phases of the tide and results are compared to those obtained for a static reference level. We first separately simulate the tide and the three PMTs that were found to be most significant for the HRE. These are caused by: (1) a flank collapse of the Cumbre Vieja Volcano (CVV) in the Canary Islands (with a 80 km3 volume representing the most likely extreme scenario); (2) an M9 coseismic source in the Puerto Rico Trench (PRT); and (3) a large submarine mass failure (SMF) in the Hudson River canyon of parameters similar to the 165 km3 historical Currituck slide, which is used as a local proxy for the maximum possible SMF. Simulations are performed with the nonlinear and dispersive long wave model FUNWAVE-TVD, in a series of nested grids of increasing resolution towards the coast, by one

  14. Reservoir impacts downstream in highly regulated river basins: the Ebro delta and the Guadalquivir estuary in Spain

    NASA Astrophysics Data System (ADS)

    Polo, María J.; Rovira, Albert; García-Contreras, Darío; Contreras, Eva; Millares, Agustín; Aguilar, Cristina; Losada, Miguel A.

    2016-05-01

    Regulation by reservoirs affects both the freshwater regime and the sediment delivery at the area downstream, and may have a significant impact on water quality in the final transitional water bodies. Spain is one the countries with more water storage capacity by reservoirs in the world. Dense reservoir networks can be found in most of the hydrographic basins, especially in the central and southern regions. The spatial redistribution of the seasonal and annual water storage in reservoirs for irrigation and urban supply, mainly, has resulted in significant changes of water flow and sediment load regimes, together with a fostered development of soil and water uses, with environmental impacts downstream and higher vulnerability of these areas to the sea level rise and drought occurrence. This work shows these effects in the Guadalquivir and the Ebro River basins, two of the largest regulated areas in Spain. The results show a 71 % decrease of the annual freshwater input to the Guadalquivir River estuary during 1930-2014, an increase of 420 % of the irrigated area upstream the estuary, and suspended sediment loads up to 1000 % the initial levels. In the Ebro River delta, the annual water yield has decreased over a 30 % but, on the contrary, the big reservoirs are located in the main stream, and the sediment load has decreased a 99 %, resulting in a delta coastal regression up to 10 m per year and the massive presence of macrophytes in the lower river. Adaptive actions proposed to face these impacts in a sea level rise scenario are also analyzed.

  15. Structure of the parasite infracommunity of Sciades proops from the Japaratuba River Estuary, Sergipe, Brazil.

    PubMed

    Carvallho, R P S; Takemoto, R M; Melo, C M; Jeraldo, V L S; Madi, R R

    2015-11-01

    The catfish species Sciades proops inhabits muddy estuaries and shallow brackish lagoons, as well as freshwater. For these reasons, it is believed that this species may act as an intermediate, definitive and paratenic host in the life cycle of many parasites. From November 2010 to November 2011 and from August 2012 to July 2013, a total of 126 specimens of Sciades proops from the estuarine region of the Japaratuba River in the state of Sergipe, Brazil, were examined for parasites, of which 84.13% were infected by at least one species: Ergasilus sp. (Copepoda) (Prevalence P = 77.78%, Mean of Intensity MI = 10.08 ± 15.48, Mean Abundance MA = 14.27 ± 7.48) in the gills, Contracaecum sp. (P = 23.02%, MI = 20.59 ± 80.58, MA =39.12 ± 4.47) in the general cavity, Procamallanus sp. (P = 0.79%, MI = 1, MA = 0.01 ± 0.09), Raphidascaroides sp. (P = 2.31%, MI = 1.33 ± 0.58, MA = 0.33 ± 0.22) and Cuccullanus sp. (Nematoda) (P = 0.79%, MI = 1, MA = 0.01 ± 0.09) in the intestine, Ancyrocephalinae (Monogenea) (P = 0.79%, MI = 1, MA = 0.01 ± 0.09) in the gills, Pseudoacanthostomumpanamense (P = 1.59%, MI = 9.00 ± 8.49, MA = 0.14 ± 1.36) in the intestine, Clinostomum sp. (P = 1.59%, MI = 17.50 ± 23.33, MA = 0.29 ± 3.03) on the body surface and two unidentified metacercariae, referred to as Metacercaria 1 (P = 0.79%; IM = 1, MA = 0.01 ± 0.09) and Metacercaria 2 (Digenea) (P = 0.79%, MI = 7, MA = 0.06 ± 0.62) in the swim bladder. Ergasilus sp. was the dominant species and thus classified as core, with Contracaecum sp. as the satellite and other species as secondary species. The spatial distribution of infection with Ergasilus sp. and Contracaecum sp. showed a typical pattern of aggregate distribution. The sex of the host did not influence parasitic infections, but infection with Ergasilus sp. showed a positive and significant correlation with biometric and epidemiologic parameters, whereas infection with Contracaecum sp. was correlated only with prevalence and abundance

  16. Shifts in vegetation affect organic carbon quality in a coastal marsh along the Hudson River Estuary

    NASA Astrophysics Data System (ADS)

    Zhang, A. H.; Corbett, J. E.; Tfaily, M. M.; Martin, I.; Ho, L.; Sun, E.; Sevilla, L.; Vincent, S.; Newton, R.; Peteet, D. M.

    2015-12-01

    To better understand carbon storage in coastal salt marshes, samples were collected from Piermont Marsh, NY (40 ̊00' N, 73 ̊55'W) located within the Hudson River Estuary. Porewater from three different vegetation sites was analyzed to compare the quality of the dissolved organic carbon. Sites contained either native or invasive vegetation with variations in live plant root depth. Porewater was taken from 0-3m in 50cm intervals, and sites were dominated either by invasive Phragmites australis, native Eleocharis , or native mixed vegetation (Spartina patens, Scirpus, and Typha angustifolia). Sites dominated by invasive Phragmites australis were found to have lower dissolved organic carbon (DOC) concentrations, lower cDOM absorption values, and more labile organic carbon compounds. The molecular composition of the DOC was determined with Fourier Transform Ion Cyclotron Mass Spectrometry (FT-ICR-MS). Labile DOC components were defined as proteins, carbohydrates, and amino sugars while recalcitrant DOC components were defined as lipids, unsaturated hydrocarbons, lignins, tannins, and condensed hydrocarbons. For the Phragmites, Eleocharis, and mixed vegetation sites, average DOC concentrations with depth were found to be 1.71 ± 1.06, 4.64 ± 1.73, and 4.62 ± 3.5 (mM), respectively and cDOM absorption values with depth were found to be 13.22 ± 4.81, 49.42 ± 10.8, and 35.74 ± 17.49 (m-1). Additionally, DOC concentrations increased with depth in the mixed vegetation and Eleocharis sites, but remained relatively constant in the Phragmites site. The percent of labile compounds in the surface samples were found to be 19.02, 14.64, and 14.07% for the Phragmites, Eleocharis, and mixed vegetation sites, respectively. These findings suggest that sites dominated by Phragmites may have more reactive DOC substrates than sites dominated by native vegetation. These results indicate that the carbon storage in marshes invaded by Phragmites would be expected to decrease over time.

  17. [Comparison of mesozooplankton communities in North Channel and North Branch of Yangtze River Estuary].

    PubMed

    Gao, Qian; Xu, Zhao-Li; Zhung, Ping

    2008-09-01

    According to the four cruises investigations in the Yangtze River Estuary from May, August and November 2004 and February 2005, and by using species diversity indices, K-dominance curves, and similarity analysis (ANOSIM), the features of mesozooplantkon communities and their dominant species in the North Channel (NC) and North Branch (NB) were analyzed, with the effects of ecological factors, especially water salinity and temperature, on the dominant species and communities in these two waters discussed. The results indicated that the NC was composed of tidal water and oligo-haline water, while the NB was featured by meso-haline or poly-haline water. Consequently, the zooplankton communities in these two waters were significantly different. In spring, the abundance and diversity of the communities were larger in NB than in NC. In NC, Sinocalanus sinicus was the only dominant species; while in NB, there were several dominate species, among which, Labidocera euchaeta was most important. In summer, the diversity of the communities in NC and NB was quite similar, but the species richness and total abundance of zooplankton were less in NC than in NB. The zooplankton in NC was made up of olio-haline communities, and that in NB was composed of brackish species, e.g., Schmackeria poplesia and Tortanus vermiculus. In autumn, similar to those in spring, the abundance and diversity of the communities were larger in NB than in NC. As usual, in NC, S. sinicus was the most important species; while in NB, the zooplankton was composed of neritic community (Paracalanus parvus, P. aculeatus, L. euchaeta, and Calanus sinicus, etc. ). In winter, the species richness and diversity were the lowest, and there were no obvious difference between the zooplankton communities in NC and NB. It was concluded that water salinity, water temperature, and their combination were the key factors determining the characters of the mesozooplanktonic communities. Water temperature mainly affected the

  18. Eelgrass Enhancement and Restoration in the Lower Columbia River Estuary, Period of Performance: Feb 2008-Sep 2009.

    SciTech Connect

    Judd, C.; Thom, R; Borde, A.

    2009-09-08

    The purpose of this study was to evaluate the ability to enhance distribution of eelgrass (Zostera marina) in the Columbia River Estuary to serve as refuge and feeding habitat for juvenile salmon, Dungeness crab, and other fish and wildlife. We strongly suspected that limited eelgrass seed dispersal has resulted in the present distribution of eelgrass meadows, and that there are other suitable places for eelgrass to survive and form functional meadows. Funded as part of the Bonneville Power Administration's call for Innovative Projects, we initiated a multistage study in 2008 that combined modeling, remote sensing, and field experimentation to: (1) Spatially predict habitat quality for eelgrass; (2) Conduct experimental plantings; and (3) Evaluate restoration potential. Baseline in-situ measurements and remote satellite observations were acquired for locations in the Lower Columbia River Estuary (LCRE) to determine ambient habitat conditions. These were used to create a habitat site-selection model, using data on salinity, temperature, current velocity, light availability, wave energy, and desiccation to predict the suitability of nearshore areas for eelgrass. Based on this model and observations in the field, five sites that contained no eelgrass but appeared to have suitable environmental conditions were transplanted with eelgrass in June 2008 to test the appropriateness of these sites for eelgrass growth. We returned one year after the initial planting to monitor the success rate of the transplants. During the year after transplanting, we carried out a concurrent study on crab distribution inside and outside eelgrass meadows to study crab usage of the habitat. One year after the initial transplant, two sites, one in Baker Bay and one in Young's Bay, had good survival or expansion rates with healthy eelgrass. Two sites had poor survival rates, and one site had a total loss of the transplanted eelgrass. For submerged aquatic vegetation (SAV) restoration projects

  19. Current status and ecological roles of Zostera marina after recovery from large-scale reclamation in the Nakdong River estuary, Korea

    NASA Astrophysics Data System (ADS)

    Park, Sang Rul; Kim, Jong-Hyeob; Kang, Chang-Keun; An, Soonmo; Chung, Ik Kyo; Kim, Jeong Ha; Lee, Kun-Seop

    2009-01-01

    Large Zostera marina meadows (covering 13.6 km 2) existed in the Nakdong River estuary on the south coast of Korea until the mid-1980s, but these Z. marina beds nearly disappeared due to reclamation of adjacent mud flats for the construction of a port and industrial complex during the late 1980s. Partial recovery of Z. marina meadows occurred recently, and Z. marina coverage of about 0.3 km 2 was observed in this estuary. In this study, shoot morphology, density, biomass, productivity, and tissue nutrient content were measured to evaluate the current status of the Z. marina meadows by comparing these data to those for persistent seagrass meadows in similar geographical areas. Additionally, we examined the ecological roles of Z. marina in this estuary after recovery from the large-scale disturbance. Shoot density (151 shoots m -2) and total biomass (141 g DW m -2) in the estuary were similar to those reported from other Z. marina meadows in Korea. Annual leaf production (1726 g DW m -2 y -1) was higher than generally observed for Z. marina in other geographical areas. These results imply that the existing Z. marina meadows in this estuary have adjusted to local environmental conditions that changed after large-scale reclamation. Estimated annual whole plant carbon (C) and nitrogen (N) incorporations based on shoot production and tissue C and N content were 810.0 g C m -2 y -1 and 59.7 g N m -2 y -1, respectively. These values were equivalent to 2.4 × 10 5 kg C y -1 and 1.8 × 10 4 kg N y -1 for all Z. marina beds in the Nakdong River estuary. This high C and N incorporation into Z. marina tissues suggests that existing Z. marina meadows play important roles in C and N cycles in this estuary. Although the currently existing Z. marina beds in this estuary are persisting and play an important ecological role, anthropogenic factors that cause seagrass declines still affect the estuary. Thus, effective management and monitoring of Z. marina beds and environmental

  20. Seasonal variation in sources and processing of particulate organic carbon in the Pearl River estuary, South China

    NASA Astrophysics Data System (ADS)

    Guo, Wei; Ye, Feng; Xu, Shendong; Jia, Guodong

    2015-12-01

    Particulate organic carbon (POC) in the Pearl River estuary (PRE), South China, along a salinity gradient from freshwater to seawater in four months was studied in order to determine its temporal and spatial changes in source and processing. Analytical parameters included chlorophyll-a (Chl-a), POC, and carbon isotopic composition of POC and the dissolved inorganic carbon (DIC) (δ13CPOC, δ13CDIC). POC varied greatly from freshwater to seawater, exhibiting a significant power law distribution with a rapid decrease (from >2.5 mg l-1 to <0.9 mg l-1) in a narrow salinity range of 0-5 and then a slow decline to ˜0.4 mg l-1 along the large salinity gradient in the estuary. POC was sourced predominantly from in situ phytoplankton, and hence largely reflective of primary production, in February, August, and November as indicated by mostly lower POC/Chl-a values (<200), and significant correlation between POC and Chl-a, as well as between δ13CPOC and δ13CDIC. But in May, soil-derived OC was dominant in freshwater and low salinity estuarine water, as suggested by low POC% in total suspended substance, low Chl-a values and high POC/Chl-a ratios, and higher δ13CPOC values that was not in parallel with δ13CDIC excursion. The offset between δ13CPOC and phytoplankton δ13C (inferred from δ13CDIC) was trivial or positive in salinity <12, but then became negative downstream, which was likely suggestive of biogeochemical change from net respiration in the upper estuary to net production in the lower and outer estuary. Our results demonstrated that in situ phytoplankton was the dominant source to the estuarine POC pool during most seasons of a year, except in May in the first phase of wet season when rainfall and river flux increased abruptly causing intensive flushing effect. We further suggested that POC may be undergone intensive processing within the PRE, which is important for understanding organic carbon delivery in this vigorous land-ocean interface.

  1. INVESTIGATIONS INTO THE EFFECTS OF SEASON AND WATER QUALITY ON OYSTERS (CRASSOSTREA VIRGINICA) AND ASSOCIATED FISH ASSEMBLAGES IN THE CALOOSAHATCHEE RIVER ESTUARY, FLORIDA: IMPLICATIONS OF ALTERED FRESHWATER INFLOW

    EPA Science Inventory

    A suite of biological and ecological responses of a Valued Ecosystem Component species, Crassostrea virginica, was used to investigate ecosystem-wide health effects of watershed alterations in the Caloosahatchee River estuary, Florida. The influence of water quality and season on...

  2. Evaluation of HCMM satellite data for estuarine tidal circulation patterns and thermal inertia soil moisture measurements. [Delaware Bay, Cooper River, and the Potomac River estuaries; Luverne, Minnesota, soil moisture, and water temperature of Lake Anna, Virginia

    NASA Technical Reports Server (NTRS)

    Wiesnet, D. R.; Mcginnis, D. F., Jr. (Principal Investigator); Matson, M.; Pritchard, J. A.

    1981-01-01

    Digital thermal maps of the Cooper River (SC) and the Potomac River estuaries were prepared from heat capacity mapping radiometer (HCMR) tapes. Tidal phases were correctly interpreted and verified. Synoptic surface circulation patterns were charted by location thermal fronts and water mass boundaries within the estuaries. Thermal anomalies were detected adjacent of a conventional power plant on the Potomac. Under optimum conditions, estuaries as small as the Cooper River can be monitored for generalized thermal/tidal circulation patterns by the HCMM-type IR sensors. The HCMM thermal inertia approach to estimating soil moisture at the Luverne (MN) test site was found to be unsatisfactory as a NESS operational satellite technique because of cloud cover interference. Thermal-IR data show similar structure of the Baltimore and Washington heat islands when compared to NOAA AVHRR thermal-IR data. Thermal anomalies from the warm water discharge water of a nuclear power plant were mapped in Lake Anna, Virginia.

  3. Estuarine Landcover Along the Lower Columbia River Estuary Determined from Compact Ariborne Spectrographic Imager (CASI) Imagery, Technical Report 2003.

    SciTech Connect

    Garono, Ralph; Robinson, Rob

    2003-10-01

    Developing an understanding of the distribution and changes in estuarine and riparian habitats is critical to the management of biological resources in the lower Columbia River. In a recently completed comprehensive ecosystem protection and enhancement plan for the lower Columbia River Estuary (CRE), Jerrick (1999) identified habitat loss and modification as one of the key threats to the integrity of the CRE ecosystem. This management plan called for an inventory of habitats as key first step in the CRE long-term restoration effort. While previous studies have produced useful data sets depicting habitat cover types along portions of the lower CRE (Thomas, 1980; Thomas, 1983; Graves et al., 1995; NOAA, 1997; Allen, 1999), no single study has produced a description of the habitats for the entire CRE. Moreover, the previous studies differed in data sources and methodologies making it difficult to merge data or to make temporal comparisons. Therefore, the Lower Columbia River Estuary Partnership (Estuary Partnership) initiated a habitat cover mapping project in 2000. The goal of this project was to produce a data set depicting the current habitat cover types along the lower Columbia River, from its mouth to the Bonneville Dam, a distance of {approx}230-km (Fig. 1) using both established and emerging remote sensing techniques. For this project, we acquired two types of imagery, Landsat 7 ETM+ and Compact Airborne Spectrographic Imager (CASI). Landsat and CASI imagery differ in spatial and spectral resolution: the Landsat 7 ETM+ sensor collects reflectance data in seven spectral bands with a spatial resolution of 30-m and the CASI sensor collects reflectance data in 19 bands (in our study) with a spatial resolution of 1.5-m. We classified both sets of imagery and produced a spatially linked, hierarchical habitat data set for the entire CRE and its floodplain. Landsat 7 ETM+ classification results are presented in a separate report (Garono et al., 2003). This report

  4. 75 FR 17382 - Small Takes of Marine Mammals Incidental to Specified Activities; Russian River Estuary Water...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-06

    ... Federal Register (74 FR 58248) for the take of marine mammals incidental to Estuary water level management... notice (74 FR 58248). In summary, harbor seals are the most abundant marine mammal found at the mouth of... published on November 12, 2009 (74 FR 58248). During the 30-day public comment period, six members of...

  5. Impact of millennial mining activities on sediments and microfauna of the Tinto River estuary (SW Spain).

    PubMed

    Ruiz, F; Borrego, J; González-Regalado, M L; López González, N; Carro, B; Abad, M

    2008-07-01

    In this paper, we analyze two short cores collected in the Tinto estuary (SW Spain), and describe the palaeoenvironmental evolution of this area during the last two millennia, along with the influence of historical mining activities and recent industrial pollution on sediments and microfauna (foraminifera and ostracoda). Although there were no significant changes in the distribution of microorganisms, a first pollution period (0-150 AD) was recorded in high sediment pollution by Cu in the shallow palaeochannels of the middle estuary. During this period and the following 1700 years, tolerant pioneer species of both foraminifera and ostracoda were found predominantly in the inner, protected areas of the estuary, while the bottom sediments were subjected to high hydrodynamic gradients, and consequently showed lower density and diversity of organisms. In the last 150 years, acid mine drainage processes, introduction of a new mining period, and the polluted inputs derived from two industrial processes resulted in increased heavy metal contamination of the bottom sediments, and corresponding extirpation of ostracodes and restriction of foraminifers to the inner zones of the estuary. PMID:18538354

  6. 78 FR 23746 - Takes of Marine Mammals Incidental to Specified Activities; Russian River Estuary Management...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-22

    ...In accordance with the regulations implementing the Marine Mammal Protection Act (MMPA) as amended, notification is hereby given that NMFS has issued an Incidental Harassment Authorization (IHA) to the Sonoma County Water Agency (SCWA) to incidentally harass, by Level B harassment only, three species of marine mammals during estuary management activities conducted at the mouth of the Russian......

  7. 76 FR 23306 - Takes of Marine Mammals Incidental to Specified Activities; Russian River Estuary Management...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-26

    ...In accordance with the regulations implementing the Marine Mammal Protection Act (MMPA) as amended, notification is hereby given that NMFS has issued an Incidental Harassment Authorization (IHA) to the Sonoma County Water Agency (SCWA) to incidentally harass, by Level B harassment only, three species of marine mammals during estuary management activities conducted at the mouth of the Russian......

  8. Pollutant fate and spatio-temporal variability in the choptank river estuary: factors influencing water quality

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Restoration of the Chesapeake Bay, a national treasure and the largest estuary in the United States, is a national priority, and documentation of progress of this restoration effort is needed. A study was conducted to examine water quality conditions in a tributary of the Chesapeake, the Choptank R...

  9. Phytotoxicity of surface waters of the Thames and Brisbane River estuaries: a combined chemical analysis and bioassay approach for the comparison of two systems.

    PubMed

    Bengtson Nash, S M; Goddard, J; Müller, J F

    2006-05-15

    The Thames Estuary, UK, and the Brisbane River, Australia, are comparable in size and catchment area. Both are representative of the large and growing number of the world's estuaries associated with major cities. Principle differences between the two systems relate to climate and human population pressures. In order to assess the potential phytotoxic impact of herbicide residues in the estuaries, surface waters were analysed with a PAM fluorometry-based bioassay that employs the photosynthetic efficienc