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Sample records for kong river estuary

  1. Hong Kong at the Pearl River Estuary: A hotspot of microplastic pollution.

    PubMed

    Fok, Lincoln; Cheung, P K

    2015-10-15

    Large plastic (>5mm) and microplastic (0.315-5mm) debris were collected from 25 beaches along the Hong Kong coastline. More than 90% consisted of microplastics. Among the three groups of microplastic debris, expanded polystyrene (EPS) represented 92%, fragments represented 5%, and pellets represented 3%. The mean microplastic abundance for Hong Kong was 5595items/m(2). This number is higher than international averages, indicating that Hong Kong is a hotspot of marine plastic pollution. Microplastic abundance was significantly higher on the west coast than on the east coast, indicating that the Pearl River, which is west of Hong Kong, may be a potential source of plastic debris. The amounts of large plastic and microplastic debris of the same types (EPS and fragments) were positively correlated, suggesting that the fragmentation of large plastic material may increase the quantity of beach microplastic debris.

  2. Influence of the Pearl River estuary and vertical mixing in Victoria Harbor on water quality in relation to eutrophication impacts in Hong Kong waters.

    PubMed

    Yin, Kedong; Harrison, Paul J

    2007-06-01

    This study presents water quality parameters such as nutrients, phytoplankton biomass and dissolved oxygen based on 11 years of water quality data in Victoria Harbor and examined how the Pearl River estuary discharge in summer and year round sewage discharge influenced these parameters. Nutrients in Victoria Harbor were strongly influenced by both the Pearl River and sewage effluent, as indicated by the high NO(3) inputs from the Pearl River in summer and higher NH(4) and PO(4) in Victoria Harbor than both its sides. N:P ratios were low in the dry season, but increased to >16:1 in the wet season, suggesting that P is potentially the most limiting nutrient in this area during the critical period in the summer. Although there were generally high nutrients, the phytoplankton biomass was not as high as one would expect in Victoria Harbor. In fact, there were high concentrations of chl near the bottom well below the photic zone. Salinity near the bottom was lower in Victoria Harbor than at the two entrances to Victoria Harbor, suggesting strong vertical mixing within Victoria Harbor. Therefore, strong vertical mixing and horizontal advection appear to play an important role in significantly reducing eutrophication impacts in Victoria Harbor. Consequently, dissolved oxygen near the bottom was low in summer, but only occasionally dipped to 2 mgL(-1) despite the high organic loading from sewage effluent.

  3. Geochemistry of tin in rivers and estuaries

    NASA Astrophysics Data System (ADS)

    Byrd, James T.; Andreae, Meinrat O.

    1986-05-01

    On the basis of measurements from a large number of rivers from pristine and polluted regions, we estimate the riverine fluxes of tin to the oceans to be 0.76 × 10 6molyr-1 for the dissolved fraction and 300-600 × 10 6 mol yr -1 for the paniculate fraction. The paniculate flux agrees with the flux calculated from denudation rates. Estuaries were found not to have a large effect upon the transport of tin to the oceans. Evidence for the remobilization of tin was found in an estuary that is highly polluted with tin from mining and smelting activities. Monobutyltin was found to be present in polluted estuaries and is presumed to be a degradation product of tributyltin additives to antifouling paint.

  4. 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

  5. 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

  6. 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

  7. 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

  8. Methane in surface waters of Oregon estuaries and rivers

    SciTech Connect

    de Angelis, M.A.; Lilley, M.D. )

    1987-05-01

    Methane concentrations in surface waters of Oregon rivers and estuaries were measured over a four-year period. Geographic variations in riverine CH{sub 4} were observed. Results from undisturbed forest streams indicate that rivers can contain high natural levels of CH{sub 4} not attributable to pollution. Lateral diffusion and runoff from saturated forest and fertilized agricultural soils may be important in determining methane levels in rivers. Methane concentrations in well-flushed estuaries appear to be controlled mainly by mixing between high CH{sub 4}-containing river water and low CH{sub 4}-containing seawater endmembers. Rivers and estuaries were found to be sources of methane to the atmosphere. Calculated daily fluxes to the atmosphere ranged from 1.2 to 71 mg CH{sub 4} sq m for rivers and from 0.04 to 21 mg CH{sub 4} sq m for estuarine samples. 24 refs., 4 figs., 3 tabs.

  9. Rhenium and Molybdenum in Rivers and Estuaries.

    NASA Astrophysics Data System (ADS)

    Walker, B. D.; Peucker-Ehrenbrink, B.

    2004-12-01

    Due to their redox-sensitive nature, the geochemical cycles of Re and Mo are linked to the global organic carbon cycle. Reducing sediments constitute a globally important sink and weathering of organic-rich sediments is responsible for a large portion of the Re and - to a lesser extent - Mo flux to the oceans (Colodner et al., 1993; Jaffe et al., 2002). Riverine concentrations of Re and Mo are a function of the river basin lithology, but are also likely to be affected by anthropogenic contributions (Colodner et al., 1995). Current estimates of global natural riverine Re flux are restricted to single analyses of four major rivers, which characterize only 23%\\ of the global freshwater flux (Colodner et al., 1993). Annual variability of Re and Mo concentrations in rivers has not been studied. A single study of Re concentrations along the salinity gradient of the Amazon shelf is suggestive of conservative mixing, but scatter in the data do not allow to exclude the possibility of Re addition in the low-salinity end of the profile (Colodner et al., 1993). Careful evaluation of samples from the Hudson River estuary using a variety of extraction techniques indicates that spike-sample equilibration was not fully achieved using commonly used methods. We have therefore developed a simple, clean and efficient method of extracting Re from filtered water samples. Our method utilizes syringe filtration, prolonged heating to achieve spike-sample equilibration, batch equilibration with TEVA resin, and extraction of Re and Mo using syringe filtration. Rhenium concentrations in the Hudson, Housatonic and Connecticut rivers are 38 pM, 6.6 pM and 14 pM, respectively, much higher than the estimated global average of 2.1 pM (Colodner et al., 1993). Molybdenum concentrations are 4.6 nM, 5.5 nM, 7.8 nM, respectively. These rivers drain basins of Precambrian basement as well as predominantly Paleozoic sediments and have been substantially urbanized. Data for a salinity profile along the

  10. 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

  11. 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

  12. 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

  13. The Pearl River Estuary Pollution Project (PREPP)

    NASA Astrophysics Data System (ADS)

    Chen, Jay-Chung; Heinke, Gary W.; Jiang Zhou, Ming

    2004-10-01

    The Pearl River, or Zhujiang River system is China's third longest river, after the Yangtze and Yellow Rivers. The Pearl River has three principal tributaries, namely, the Xijiang River, Beijiang River and Dongjiang River. It also receives several other small tributaries developed within the Pearl River Delta. Its average annual flow rate approximately 10 , 000m3s-1 is exceeded only by the Yangtze River. Its length is 2 , 214 km and drains an area of 453 , 690km2, most of which is in Southern China and with a small part in Vietnam. Parts of the provinces of Yunnan, Guizhou, Guangxi, Guangdong, Hunan and Jiangxi drain to the Pearl River system.

  14. Potential intertidal habitat restoration sites in the Duwamish River estuary

    SciTech Connect

    Tanner, C.D.

    1991-12-01

    Restoration of wetland habitats in highly urbanized areas is generally constrained by scarcity of opportunity, adverse impacts of surrounding land use, and cost. Although areal wetland losses approach 98% in Seattle's Duwamish River estuary, the system continues to support important salmonid runs, as well as a variety of bird and mammal species. Estuarine-dependent organisms are likely limited by quality and quantity of intertidal habitat in the system. Because the long-range, estuary-wide benefit of site-specific mitigation and restoration projects is limited, it is imperative to develop estuary-wide restoration plans. Towards this end, an inventory and analysis of potential intertidal habitat restoration sites has been completed for the Duwamish River estuary. Twenty-four sites, ranging in size from 0.8 to 25 acres were identified and comparative functional potential assessed. The majority of these sites (18) occur in the upper estuary. Two sites are located in Elliott Bay, and four are located near the historic mouth of the river in the vicinity of Harbor Island. Spatial data have been developed in geographic information system (GIS) format. Other site-specific data relative to habitat restoration has also been assembled.

  15. 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...

  16. 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 ...

  17. 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...

  18. PCB-resistant diatoms in the Hudson River estuary

    NASA Astrophysics Data System (ADS)

    Cosper, Elizabeth M.; Wurster, Charles F.; Bautista, Mark F.

    1988-02-01

    Diatom cells that are resistant, as well as sensitive, to the toxicity of polychlorinated biphenyls (PCB) are widespread throughout the highly polluted Hudson River estuary. A study of the distribution of PCB resistance among populations of the diatoms, Thalassiosira nordenskioldii and Asterionella glacialis, revealed few spatial or temporal patterns for the trait during spring and summer. The number of estuarine clones of A. glacialis tolerant of more than 25 ppb of PCB was greater than twice the number of clones isolated from nearshore waters at Sandy Hook, NJ. This suggests that selection pressure for PCB resistance is greater in the estuary than in the New York Bight apex. If specific sites of selection exist, the mixing of cells within the estuary may be rapid enough to distribute resistant clones throughout the estuary, or the selection process may involve a generalized response to a multitude of pollutants. Several clones of both species tested were not only tolerant of PCB, but were actually enhanced in their growth in the presence of PCB. Such clones were distributed throughout the estuary during both seasons. Selection in the estuary favours not only resistant strains of diatoms, but forms that may utilize organic pollutants.

  19. 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.

  20. 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.

  1. 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.

  2. Trace metals in sediments of a Mediterranean estuary affected by human activities (Acheloos river estuary, Greece).

    PubMed

    Dassenakis, M; Degaita, A; Scoullos, M

    1995-05-19

    Trace metals were studied in the sediments of the ecologically, economically and scientifically important estuary of the Acheloos river, in western Greece. Human activities (dams, agriculture, traffic, etc.) influence the estuarine system of Acheloos and in combination with the hydrological, mineralogical and morphological characteristics of the estuary affect the chemical behaviour and the distribution patterns of trace metals in its sediments. The large scale disturbance of the system is imminent in the near future as it is planned to divert approximately 50% of the river water. A study of the distribution patterns of trace metals revealed that in the estuary there are zones with different metal levels. The concentrations of most metals (Al, Fe, Cu, Ni, Zn) are elevated in three of these zones (upstream, sill, seawards). A different behaviour was observed for Mn due to its association with carbonates that were observed in significant concentrations throughout the estuarine zone. A sequential extraction procedure, applied to the sediments, indicated low percentages of easily exchangeable metals, increased mobility of Cu and Zn and increased association of Ni, Cr and Fe with the aluminosilicate lattice. Although the river is not considered to be heavily polluted, some metals have shown an enrichment in the surface sediments as a result of general anthropogenic activities not derived from point sources.

  3. 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

  4. 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.

  5. Trace metals in the Góta river estuary

    NASA Astrophysics Data System (ADS)

    Danielsson, Lars-Göran; Magnusson, Bertil; Westerlund, Stig; Zhang, Kerong

    1983-07-01

    The concentrations of the trace metals Cd, Cu, Fe, Ni, Pb and Zn in the Göta River estuary have been investigated. The following metal fractions have been determined: acid-leachable, dissolved, labile and particulate. The estuary represents a salt wedge type estuary and is situated in a densely populated region of Sweden. The metal concentrations found for the dissolved fraction is in the range of what can be considered as background levels for freshwater. It is difficult to evaluate any estuarine processes other than conservative mixing for Cd, Cu, Ni and Zn. The dissolved levels in the freshwater end member are Cd, 9-25 ngl -1; Cu, 1·1-1·4 μgl -1; Fe, 20-75 μg l -1: Ni, 0·7-0·9 μg l -1: Pb 0·09-0·2 μg l -1; and Zn, 6-7 μg l -1: The results from the acid-leachable fraction show that at high suspended load the particles sediment in the river mouth. The trace metal levels in this fraction are subject to large variations.

  6. 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.

  7. 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

  8. Estimation of bed shear stresses in the pearl river estuary

    NASA Astrophysics Data System (ADS)

    Liu, Huan; Wu, Jia-xue

    2015-03-01

    Mean and fluctuating velocities were measured by use of a pulse coherent acoustic Doppler profiler (PC-ADP) and an acoustic Doppler velocimeter in the tidal bottom boundary layer of the Pearl River Estuary. The bed shear stresses were estimated by four different methods: log profile (LP), eddy correlation (EC), turbulent kinetic energy (TKE), and inertial dissipation (ID). The results show that (a) all four methods for estimating bed stresses have advantages and disadvantages, and they should be applied simultaneously to obtain reliable frictional velocity and to identify potential sources of errors; (b) the LP method was found to be the most suitable to estimate the bed stresses in non-stratified, quasi-steady, and homogeneous flows; and (c) in the estuary where the semi-diurnal tidal current is dominant, bed shear stresses exhibit a strong quarter-diurnal variation.

  9. 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.

  10. 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.

  11. 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

  12. 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)

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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

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

    USGS Publications Warehouse

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

    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.

  19. Plutonium AMS measurements in Yangtze River estuary sediment

    NASA Astrophysics Data System (ADS)

    Tims, S. G.; Pan, S. M.; Zhang, R.; Fifield, L. K.; Wang, Y. P.; Gao, J. H.

    2010-04-01

    The Yangtze River is the largest single source of sediment to the continental shelf of the East China Sea. The quantity of material exported by the river is expected to decrease substantially as a consequence of an extensive continuing program of dam construction within the river catchment. We report here AMS measurements of plutonium isotope concentrations and ratios for selected depth increments from a sediment core, collected from the sub-aqueous delta of the Yangtze River estuary. The Pu derives from atmospheric nuclear weapons testing in the 1950s and 1960s, and is potentially a useful tracer of sediment deposition times in the marine environment. The results show considerable structure in the depth-concentration profile, and offer an excellent opportunity to compare Pu with the more commonly used 137Cs isotopic tracer. The AMS data show superior sensitivity and indicate that the 240Pu/ 239Pu ratio can provide a check on the deposition dates. The changes in the 240Pu and 239Pu concentrations and the 240Pu/ 239Pu ratios with sediment depth all indicate the possibility of using Pu as a geochronological tool for coastal sediment studies.

  20. 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.

  1. 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

  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. 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.

  4. 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

  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.

  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. Identifying nearshore groundwater and river hydrochemical variables influencing water quality of Kaoping River Estuary using dynamic factor analysis

    NASA Astrophysics Data System (ADS)

    Kuo, Yi-Ming; Jang, Cheng-Shin; Yu, Hwa-Lung; Chen, Su-Chin; Chu, Hone-Jay

    2013-04-01

    SummaryThe Kaoping River Estuary receives a large amount of nonpoint source pollution and sedimentary discharge from the Kaoping and Tungkang Rivers each year. The Kaoping River Estuary is an integral part of the Kaoping River, shelf, and submarine canyon, which makes prediction of water quality variation difficult. This study attempts to determine the main factors regulating temporal and spatial variations in the water quality in the Kaoping River Estuary over a 9-year period (2003-2011), using dynamic factor analysis (DFA) and min/max autocorrelation factor analysis (MAFA). The result from the MAFA shows that Chlorophyll-a (Chl-a) has the highest canonical correlation coefficient with the min/max autocorrelation factor (MAF) axis of water quality. Therefore, Chl-a can be used as an indicator of water quality in the Kaoping River Estuary. The water quality and environmental variables measured downstream of the Kaoping and Tungkang Rivers, as well as submarine groundwater, influence temporal variations of Chl-a in the estuary. The optimal DFA model successfully described Chl-a variations (coefficient of efficiency = 0.969) in the Kaoping River Estuary. DFA results indicate that dissolved oxygen (DO), total suspended sediment (TSS), dissolved inorganic nitrogen (DIN), chemical oxygen demand (COD), as well as the biological oxygen demand (BOD) of river discharge, and the ammonium-nitrogen (NH4-N) concentration of groundwater discharge significantly influenced Chl-a dynamics. Submarine groundwater discharge, which is a significant source of nutrients for the coastal ocean, appears to impact the level of Chl-a concentration substantially. Understanding the relationship between environmental variables and the variability of Chl-a concentration provides a useful approach for setting water quality criteria and pollution prevention plans for the Kaoping River Estuary.

  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. 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.

  10. 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.

  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. Freshwater runoff and salinity distribution in the Loxahatchee River estuary, southeastern Florida, 1980-1982

    SciTech Connect

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

    1984-01-01

    During a recent study, freshwater mixed with seawater over a distance of 5 to 10 river miles in the Loxahatchee River estuary. 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. 15 refs., 21 figs., 4 tabs.

  13. 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.

  14. Hydrology, sediment circulation and long-term morphological changes in highly urbanized Shenzhen River estuary, China: A combined field experimental and modeling approach

    NASA Astrophysics Data System (ADS)

    Zhang, Shiyan; Mao, Xian-zhong

    2015-10-01

    The Shenzhen River estuary is a small estuary in highly urbanized regions between Shenzhen and Hong Kong, China. An increasing amount of sediment has been observed to accumulate in the estuary, imposing a severe impact on the ecological environment. In this study we utilized a series of hydrographic and bathymetry surveys to study the hydrology, sediment transport and morphological processes in the estuary. Flow and sediment circulation patterns in different seasons were inferred using current velocity, salinity and suspended sediment concentration (SSC) time series collected in the hydrographic surveys in conjunction with fathometer profiles in bathymetry surveys. Historical time series at two stations were also analyzed by Mann-Kendall test for possible trends of the driving forces for estuarine morphological processes. The two-dimensional depth-averaged DELFT numerical model was employed to simulate the flow, salinity and SSC fields during the synchronous surveys and to predict the long-term morphological processes in the estuary. A bimodal SSC distribution was observed with two high-SSC zones separated by a low-SSC zone near the central bay, which cannot be explained by the conventional nongravitational transport theory of Postma (1967). It is hypothesized that sediment circulation in the estuary can be separated into two different systems: the "tidal zone" is under the influence of marine sediment from the Pearl River estuary, whereas the "fluvial zone" is mainly affected by terrestrial sediment from the river. Sediment mass exchange between the two systems is limited due to the presence of the low-SSC zone, the location of which could vary with the relative strengths of river flow and tides. The trend analysis of historical time series shows that the river discharge and the mean sea level are increasing and the flood tide range and the ebb tide range are decreasing. These trends are closely related to the intense human activities in the urbanization of

  15. 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.

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

    USGS Publications Warehouse

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

    2015-01-01

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

  17. 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.

  18. Trace Element Signatures of Particles in the Fraser River Estuary

    NASA Astrophysics Data System (ADS)

    Snauffer, A. M.; Menard, O.; Kieffer, B.; Francois, R. H.; Weis, D. A.; Pcigr

    2010-12-01

    Characterization of trace element transport via particles at the estuarine boundary is critical to understanding the processes involved in translating these signatures to the ocean. The Fraser River in British Columbia, Canada, is the largest river by volume flowing from the Pacific coast and dumps 20 million tons of sediment into the ocean per year, yet its trace elements have not been studied extensively. The aim of this study is to determine the Sr, Nd, Hf and Pb signatures of suspended matter in the Fraser River estuary. We collected 20L water samples at 3m depth at 12 locations along the north arm of the Fraser River, along the salinity gradient from freshwater to saline water approaching open straight values of ~25 per mil. Samples were allowed to settle and then filtered. Settled particulate matter was taken from each sample and digested in high-pressure vessels. Sr, Nd, Hf, and Pb were separated using ion exchange chromatography columns. Sr and Nd isotopes were analyzed on a TIMS (Thermo Finnigan Triton-TI); Hf and Pb were measured with a MC-ICP-MS (Nu Plasma). The measured ratios were 87Sr/86Sr = 0.71051 to 0.71289, 143Nd/144Nd = 0.51203 to 0.51221 and 176Hf/177Hf = 0.28253 to 0.28267 in the river and 0.70961, 0.51220 and 0.28273 respectively in the open straight. They reflect the local terrane compositions [2.3]. The collected particles have relatively radiogenic signatures compared with those obtained by Cameron and Hattori [1] between Lillooet and Hope but similar to those from higher in the river, i.e. they have a signature similar to older terranes drained by the Fraser headwaters. Between Hope and Vancouver, the Fraser River drains younger mantle-derived batholiths (Coast Belt). Therefore a more juvenile signature was expected for the particles collected at the mouth of the river. A possible explanation for this unexpected radiogenic signature is a difference in flow rate between the 1993 sampling (~3000m3/s) and ours in 2010 (~5500m3/s). The

  19. 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

  20. 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.

  1. Seasonal Distribution and Movements of Atlantic and Shortnose Sturgeon in the Penobscot River Estuary, Maine

    USGS Publications Warehouse

    Zydlewski, Joseph; Fernandes, Stephen J.; Zydlewski, Gayle B.; Wippelhauser, Gail S.; Kinnison, Michael T.

    2016-01-01

    Relatively little is known about the distribution and seasonal movement patterns of shortnose sturgeon Acipenser brevirostrum and Atlantic sturgeon Acipenser oxyrinchus oxyrinchus occupying rivers in the northern part of their range. During 2006 and 2007, 40 shortnose sturgeon (66–113.4 cm fork length [FL]) and 8 Atlantic sturgeon (76.2–166.2 cm FL) were captured in the Penobscot River, Maine, implanted with acoustic transmitters, and monitored using an array of acoustic receivers in the Penobscot River estuary and Penobscot Bay. Shortnose sturgeon were present year round in the estuary and overwintered from fall (mid-October) to spring (mid-April) in the upper estuary. In early spring, all individuals moved downstream to the middle estuary. Over the course of the summer, many individuals moved upstream to approximately 2 km of the downstream-most dam (46 river kilometers [rkm] from the Penobscot River mouth [rkm 0]) by August. Most aggregated into an overwintering site (rkm 36.5) in mid- to late fall. As many as 50% of the tagged shortnose sturgeon moved into and out of the Penobscot River system during 2007, and 83% were subsequently detected by an acoustic array in the Kennebec River, located 150 km from the Penobscot River estuary. Atlantic sturgeon moved into the estuary from the ocean in the summer and concentrated into a 1.5-km reach. All Atlantic sturgeon moved to the ocean by fall, and two of these were detected in the Kennebec River. Although these behaviors are common for Atlantic sturgeon, regular coastal migrations of shortnose sturgeon have not been documented previously in this region. These results have important implications for future dam removals as well as for rangewide and river-specific shortnose sturgeon management.

  2. 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

  3. 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.

  4. 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.

  5. 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.

    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

  6. 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.

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

    USGS Publications Warehouse

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

    2013-01-01

    Tropical 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.

  8. 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.

  9. 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...

  10. 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).

  11. Mutagenicity and genotoxicity of suspended particulate matter in the Seine river estuary.

    PubMed

    Vincent-Hubert, Françoise; Heas-Moisan, Karine; Munschy, Catherine; Tronczynski, Jacek

    2012-01-24

    Highly mutagenic compounds such as some PAHs have been identified in surface waters and sediments of the Seine river estuary. Suspended particulate matter (SPM) represents a dynamic medium that may contribute to the exposure of aquatic organisms to toxic compounds in the water column of the estuary. In order to investigate major sources of mutagenic contaminants along the estuary, water samples were taken at 25 m downstream of the outlet of an industrial wastewater-treatment plant (WWTP). SPM samples were analyzed for their genotoxicity with two short-term tests, the Salmonella typhimurium mutagenicity assay (TA98+S9 mix) and the comet assay in the human HepG2 cell line. Sampling sites receiving effluents from a chemical dye industry and WWTP showed the highest mutagenic potencies, followed by petrochemical industries, petroleum refinery and pulp and paper mills. These data indicate that frame-shift mutagens are present in the Seine river estuary. Furthermore, the comet assay revealed the presence of compounds that were genotoxic for human hepatocytes (HepG2 cells). We also observed a high level of mutagenic potency in the sediment of the lower estuary (3 × 10⁴ revertants/g). The source of mutagenic and genotoxic compounds seems to be associated with various types of effluents discharged in the Seine river estuary. Both test systems resulted in the same assessment of the genotoxicity of particulate matter, except for three of the 14 samples, underlying the complementarity of bioassays.

  12. Particulate organic matter predicts bacterial productivity in a river dominated estuary

    NASA Astrophysics Data System (ADS)

    Crump, B. C.

    2015-12-01

    Estuaries act as coastal filters for organic and inorganic fluvial materials in which microbial, biogeochemical, and ecological processes combine to transform organic matter and nutrients prior to export to the coastal ocean. The function of this estuarine 'bioreactor' is linked to the residence times of those materials and to rates of microbial heterotrophic activity. Our ability to forecast the impact of global change on estuarine bioreactor function requires an understanding of the basic controls on microbial community activity and diversity. In the Columbia River estuary, the microbial community undergoes a dramatic seasonal shift in species composition during which a spring bacterioplankton community, dominated by Flavobacteriaceae and Oceanospirillales, is replaced by a summer community, dominated by Rhodobacteraceae and several common marine taxa. This annual shift occurs in July, following the spring freshet, when river flow and river chlorophyll concentration decrease and when estuarine water residence time increases. Analysis of a large dataset from 17 research cruises (1990-2014) showed that the composition of particulate organic matter in the estuary changes after the freshet with decreasing organic carbon and nitrogen content, and increasing contribution of marine and autochthonous estuarine organic matter (based on PO13C and pigment ratios). Bacterial production rates (measured as leucine or thymidine incorporation rates) in the estuary respond to this change, and correlate strongly with labile particulate nitrogen concentration and temperature during individual sampling campaigns, and with the concentration of chlorophyll in the Columbia River across all seasons. Regression models suggest that the concentration of labile particulate nitrogen and the rate of bacterial production can be predicted from sensor measurements of turbidity, salinity, and temperature in the estuary and chlorophyll in the river. These results suggest that the quality of

  13. 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.

  14. [Hydrologic distribution characteristics of HAB frequent occurrence area in the outer Changjiant River estuary].

    PubMed

    Zhu, Dedi; Pan, Yuqiu; Xu, Weiyi; Chen, Qiaoyun

    2003-07-01

    Based on survey data, this paper analysed the hydrologic characteristics of HAB frequent occurrence area in the outer Changjiang River estuary. The results showed that this area is an area in which the plume front with a salinity of 17-30 in the outer Changjang River estuary, the divergent surface current of the plume front and the upwelling of the high salinity Taiwan bottom warm current are coexisted. In Spring and Summer, the diluted Changjiang River water of this area changed its flow direction under the effect of southwest-northeastward current, possibly due to the large runoff from the Changjiang River to the sea. The upwelling usually occurred at the west side slope between the first turning point and the deep slot top of the outer Changjiang River estuary. This turning point was on the north side in Spring and on the south side in Summer, but in Autumn, no turning point was existed, possibly due to the small runoff. The distribution characteristics of residual current in Spring and Summer was that the adjacent area of plume front was the convergent area of surface and bottom currents, the surface residual current in the upwelling area was at divergent, and the bottom residual current had the characteristics of converging toward the Changjiang River estuary along the deep slot.

  15. 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...

  16. Ratio of nitrogen to phosphorus in the Pearl River and effects on the estuarine coastal waters: Nutrient management strategy in Hong Kong

    NASA Astrophysics Data System (ADS)

    Yin, Kedong; Harrison, Paul J.; Broom, Malcolm; Chung, C. H.

    The Pearl River is the second largest river in China, and has a 454,000 km 2 drainage basin. Excess nutrients can result in algal blooms, or even harmful algal blooms and subsequent dissolved oxygen (DO) consumption can lead to hypoxia. However, not all nutrients are equal; only one nutrient relative to other nutrients is the most limiting for algal biomass production and the other nutrients that are in excess cannot be used to produce a further increase in an algal bloom. Therefore, the strategy of nutrient pollution control is to remove the most limiting nutrient from the sewage effluent to minimize eutrophication impacts on the receiving waters. This, in turn, determines the type and level of sewage treatment. In the Pearl River, nitrogen (N) is very high and phosphorus (P) is relatively low, leading to a very high N:P ratio. The Pearl River flows into coastal waters in the South China Sea and heavily influences Hong Kong waters located to the east of the Pearl River estuary. When the Hong Kong government planned to upgrade the domestic sewage facility to biological treatment, this triggered the scientific question of which nutrient, N or P is the most limiting nutrient and the answer to this question became critical in making the management decision on the treatment facilities for removal of N or P, which bears a huge financial implication. In the past, because N is high in southern waters, it was thought that any addition of N would exceed the environmental assimilation capacity and result in algal blooms. Therefore, N has been typically considered for removal from sewage effluent. However, evidence revealed that P was the most limiting nutrient in the southern waters of Hong Kong and it actually limits phytoplankton biomass accumulation and potentially limits bacterial DO consumption. Hence, the removal of P has been suggested to receive priority over N removal, if there is a need for the future elevation of treatment levels. However, as this conclusion is

  17. The characteristics of nutrients and eutrophication in the Pearl River estuary, South China.

    PubMed

    Huang, X P; Huang, L M; Yue, W Z

    2003-01-01

    In the spring of 1998, 24-h time series and synchronization of vertical profiles of NO(3)-N, NO(2)-N, NH(3)-N, PO(4)-P, chlorophyll a, suspended substance, salinity, temperature and other chemical parameters were taken at 10 stations in the Pearl River estuary in order to analyze the status and characteristics of nutrients and eutrophication. The results indicated that dissolved inorganic nitrogen (DIN) mainly came from the four river channels in the main estuary, and NO(3)-N was the main form of DIN in most area. The concentration of DIN was general above 0.30 mg l(-1) in the estuary, and more than 0.50 mgl(-1) in most part. Phosphate from four river channels was not the main sources, but land-based sources from the area near Shenzhen Bay or along the estuary were obvious, and other land-based sources outside the estuary brought by coastal current and flood tide current were also the main contributions. The concentration of phosphate was generally about 0.015 mg l(-1) except the area near Shenzhen Bay. The ratio of N:P was generally high, and it was higher in the north than in the south. The highest ratio was higher than 300, and the lowest one was over 30. The concentration of chlorophyll a was about 0.8-7.8 mg m(-3), and turbidity and phosphate may be the main two limiting factors for algal bloom in the estuary. The concentration of nutrients decreased slightly in the past decade, but still stayed at a high level. The nutrients mainly came from domestic sewage, industrial wastewater, agriculture fertilizer and marine culture in the Pearl River estuary.

  18. 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)

  19. Sedimentary Records of Hyperpycnal Flows and the Influence of River Damming on Sediment Dynamics of Estuaries: Examples from the Nelson, Churchill, Moisie and Sainte-Marguerite Rivers (Canada)

    NASA Astrophysics Data System (ADS)

    St-Onge, G.; Duboc, Q.; Boyer-Villemaire, U.; Lajeunesse, P.; Bernatchez, P.

    2015-12-01

    Sediment cores were sampled in the estuary of the Nelson and Churchill Rivers in western Hudson Bay, as well as in the estuary of the Moisie and Sainte-Marguerite Rivers in Gulf of St. Lawrence in order to evaluate the impact of hydroelectric dams on the sedimentary regime of these estuaries. The gravity cores at the mouth of the Nelson River recorded several cm-thick rapidly deposited layers with a reverse to normal grading sequence, indicating the occurrence of hyperpycnal flows generated by major floods during the last few centuries. These hyperpycnal flows were probably caused by ice-jam formation, which can increase both the flow and the sediment concentration following the breaching of such natural dams. Following the construction of hydroelectric dams since the 1960s, the regulation of river discharge prevented the formation of hyperpycnal flows, and hence the deposition of hyperpycnites in the upper part of the cores. In the core sampled in the estuary of the Churchill River, only one hyperpycnite was recorded. This lower frequency may be due to the enclosed estuary of the Churchill River, its weaker discharge and the more distal location of the coring site.In the Gulf of St. Lawrence, grain size measurements allowed the identification of a major flood around AD 1844±4 years in box cores from both the Sainte-Marguerite and Moisie Rivers, whereas a drastic decrease in variations in the median grain size occurred around AD ~1900 in the estuary of the Sainte-Marguerite River, highlighting the offshore impact of the SM1 dam construction in the early 1900s. Furthermore, sedimentological variations in the box cores from both estuaries have been investigated by wavelet analysis and the sharp disappearance of high frequencies around AD 1900 in the estuary of the dammed river (Sainte-Marguerite River), but not in the estuary of the natural river (Moisie River), also provides evidence of the influence of dams on the sedimentary regime of estuaries.

  20. Transport and deposition of river sediment in the Changjiang estuary and adjacent continental shelf

    USGS Publications Warehouse

    Milliman, John D.; Huang-ting, S.; Zuo-sheng, Y.; Mead, R.H.

    1985-01-01

    Hydrographic observations, suspended-sediment measurements, and historical data indicate transport paths and sinks for sediment within the Changjiang estuary and adjacent shelf. Most of the sediment transported by the Changjiang to the ocean is carried through the North Channel of the South Branch. Sediment transport is directly related to river stage, but tidal phase (spring vs neap tides) also plays an important role. An estimated 40% of the sediment load in the river is deposited in the estuary, mostly in and seaward of the South Channel. The remaining sediment is deposited directly offshore during flood seasons, but much is resuspended and carried southward by subsequent winter storms. ?? 1985.

  1. Eutrophication Links between the Watershed and Estuary in the Neuse River Basin, NC

    NASA Astrophysics Data System (ADS)

    Showers, W. J.; Paerl, H. W.

    2005-05-01

    The Neuse River drains into the Neuse River Estuary and Pamlico Sound, which is part of the second largest estuarine ecosystem in the United States and a key nursery for Mid and Southeast Atlantic fisheries. RiverNet, ModMon, and now FerryMon have monitored nutrient fluxes in the watershed and ecosystem responses in the estuary. Poor water quality in the 1980's led to a phosphorus ban in the basin that decreased P inputs to the watershed and improved water quality in the freshwater portions of the basin. High temporal resolution nutrient monitoring in the river indicates that significant flux variations are associated with point sources, and that N fluxes have been underestimated by previous monitoring efforts. N loss in the watershed is associated with hydric soils that are primarily located in the lower coastal plain. The 17O composition of nitrate suggests that Amospherically Deposited Nitrogen (A.D.N.) is event driven and is controlled by land use in the sub-basin. New regulations imposed by the State of NC are decreasing N fluxes in the watershed, but these fluxes are highly variable and controlled to some extent by extreme rainfall events that result from direct hurricane strikes and droughts. The greater decrease in P flux to the estuary compared to N flux (which has decreased slightly or remained the same) has reduced P-limited primary production in the freshwater upper portion of the estuary. This limits the N assimilation in this region, and allows more efficient N transport to N-sensitive coastal waters in the lower portion of the estuary. Chl a and phytoplankton pigment monitoring in the estuary indicate that site of the maximum primary productivity has moved form the upper estuary in the 1970's and 1980's to the lower estuary today. This displacement of the eutrophication gradient may explain the reduction of Cyanobacteria algae blooms in the upper estuary, and the increase in harmful algae blooms, hypoxia, and declines in fisheries habitats in the

  2. 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

  3. 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.

  4. 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.

  5. 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

  6. 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

  7. 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

  8. Dissolved inorganic nutrients and chlorophyll A in an estuary receiving sewage treatment plant effluents: Cachoeira River estuary (NE Brazil).

    PubMed

    Silva, Maria Aparecida Macêdo; Eça, Gilmara Fernandes; Santos, Danielle Felix; Guimarães, Alonso Góes; Lima, Michelle Coêlho; de Souza, Marcelo Friederichs Landim

    2013-07-01

    Sampling was conducted monthly during a transition period between the dry and rainy seasons in order to evaluate the effectiveness of a municipal sewage treatment plant (STP) in eutrophication control. STP effluent and fluvial input data were also estimated. In the dry period, high concentrations of nutrients, chlorophyll a (up to 360 μg L(-1)), and anoxia in bottom waters were observed in the upper portion of the estuary. Nitrate was scarce during the dry months, although high concentrations were observed at the river sources and the upper estuary. The N:P and Si:P molar ratios were usually below 16:1, and the Si:N ratio was higher than 1:1. The fluvial inputs were a greater source of nutrients to the estuary than the STP, but nutrient loading by these effluents were also important in contributing to the eutrophication of the upper estuarine zone, especially in the dry season when symptoms were more intense.

  9. 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

  10. 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

  11. 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

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

    PubMed

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

    2015-08-11

    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.

  13. 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

  14. Occurrence and risk assessment of antibiotics in river water in Hong Kong.

    PubMed

    Deng, Wenjing; Li, Na; Zheng, Hailong; Lin, Huiying

    2016-03-01

    The occurrence and distribution of six typical antibiotics in the main rivers of Hong Kong were investigated using high-performance liquid chromatography electrospray ionization tandem mass spectrometry (HPLC-ES-MS/MS). The results revealed that the antibiotics were widely distributed in the area studied. Of the target antibiotics, ofloxacin was the most frequently detected in the rivers, with a detection rate of 69.6% and a median concentration of 0.7ng/L. Sulfadimidine (n.d-580.4ng/L) and doxycycline (n.d-82.2ng/L), with detection frequencies of 65.2% and 30.4%, respectively, were found at the same level as in rivers in North America, Spain, France, Australia, and in the Yangtze and Pearl Rivers of China, while the other target antibiotics were found at lower levels. According to the ratios of the measured environmental concentration to the predicted no-effect concentration, ofloxacin and doxycycline could present a medium to low ecological risk to algae, while sulfonamides posed no obvious ecological risk to the relevant aquatic organisms (algae, Daphnia magna, and fish). A high detection rate of antibiotics occurred in densely populated areas, revealing that population activities might be greatly contributing to the increasing levels of antibiotics in the area. Thus, the residues of antibiotics present in the waters of Hong Kong need to be closely monitored. PMID:26685784

  15. Occurrence and risk assessment of antibiotics in river water in Hong Kong.

    PubMed

    Deng, Wenjing; Li, Na; Zheng, Hailong; Lin, Huiying

    2016-03-01

    The occurrence and distribution of six typical antibiotics in the main rivers of Hong Kong were investigated using high-performance liquid chromatography electrospray ionization tandem mass spectrometry (HPLC-ES-MS/MS). The results revealed that the antibiotics were widely distributed in the area studied. Of the target antibiotics, ofloxacin was the most frequently detected in the rivers, with a detection rate of 69.6% and a median concentration of 0.7ng/L. Sulfadimidine (n.d-580.4ng/L) and doxycycline (n.d-82.2ng/L), with detection frequencies of 65.2% and 30.4%, respectively, were found at the same level as in rivers in North America, Spain, France, Australia, and in the Yangtze and Pearl Rivers of China, while the other target antibiotics were found at lower levels. According to the ratios of the measured environmental concentration to the predicted no-effect concentration, ofloxacin and doxycycline could present a medium to low ecological risk to algae, while sulfonamides posed no obvious ecological risk to the relevant aquatic organisms (algae, Daphnia magna, and fish). A high detection rate of antibiotics occurred in densely populated areas, revealing that population activities might be greatly contributing to the increasing levels of antibiotics in the area. Thus, the residues of antibiotics present in the waters of Hong Kong need to be closely monitored.

  16. 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.

  17. Trace metals in estuaries in the Russian Far East and China: case studies from the Amur River and the Changjiang.

    PubMed

    Shulkin, Vladimir; Zhang, Jing

    2014-11-15

    This paper compares the distributions of dissolved and particulate forms of Mn, Fe, Ni, Cu, Zn, Cd, and Pb in the estuaries of the largest rivers in East Asia: the Amur River and the Changjiang (Yangtze River). High suspended solid concentrations, elevated pH, and relatively low dissolved trace metal concentrations are characteristics of the Changjiang. Elevated dissolved Fe and Mn concentrations, neutral pH, and relatively low suspended solid concentrations are characteristics of the Amur River. The transfer of dissolved Fe to suspended forms is typical in the Amur River estuary, though Cd and Mn tend to mobilize to solution, and Cu and Ni are diluted in the estuarine system. Metal concentrations in suspended matter in the Amur River estuary are controlled by the ratio of terrigenous riverine material, enriched in Al and Fe, and marine biogenic particles, enriched in Cu, Mn, Cd, and in some cases Ni. The increase in dissolved forms of Mn, Fe, Ni, Cu, Cd, and Pb compared with river end-member is unique to the Changjiang estuary. Particle-solution interactions are not reflected in bulk suspended-solid metal concentrations in the Changjiang estuary due to the dominance of particulate forms of these metals. Cd is an exception in the Changjiang estuary, where the increase in dissolved Cd is of comparable magnitude to the decrease in particulate Cd. Despite runoff in the Amur River being lower than that in the Changjiang, the fluxes of dissolved Mn, Zn and Fe in the Amur River exceed those in the Changjiang. Dissolved Ni, and Cd fluxes are near equal in both estuaries, but dissolved Cu is lower in the Amur River estuary. The hydrological and physico-chemical river characteristics are dominated at the assessment of river influence on the adjoining coastal sea areas despite differences in estuarine processes.

  18. 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...

  19. 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...

  20. 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.

  1. 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...

  2. 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...

  3. 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...

  4. 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.

  5. 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...

  6. 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...

  7. [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.

  8. 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...

  9. 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) ...

  10. Trace metal distribution in sediments of the Pearl River Estuary and the surrounding coastal area, South China.

    PubMed

    Ip, Carman C M; Li, Xiang-Dong; Zhang, Gan; Wai, Onyx W H; Li, Yok-Sheung

    2007-05-01

    Surface sediments and sediment cores collected at the Pearl River Estuary (PRE) and its surrounding coastal area were analysed for total metal concentrations, chemical partitioning, and Pb isotopic compositions. The distribution of Cu, Cr, Pb, and Zn demonstrated a typical diffusion pattern from the land to the direction of the sea. Two hotspots of trace metal contamination were located at the mixed zone between freshwater and marine waters. The enrichment of metals in the sediments could be attributed to the deposition of the dissolved and particulate trace metals in the water column at the estuarine area. The similar Pb isotopic signatures of the sediments at the PRE and its surrounding coastal area offered strong evidence that the PRE was a major source of trace metals to the adjacent coastal area. Slightly lower (206)Pb/(207)Pb ratios in the coastal sediments may indicate other inputs of Pb in addition to the PRE sources, including the inputs from Hong Kong and other parts of the region.

  11. 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

  12. 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.

  13. Fish utilization of a salt marsh intertidal creek in the Yangtze River estuary, China

    NASA Astrophysics Data System (ADS)

    Jin, Binsong; Fu, Cuizhang; Zhong, Junsheng; Li, Bo; Chen, Jiakuan; Wu, Jihua

    2007-07-01

    The structure and temporal variations of the fish community in salt marshes of Chinese estuaries are poorly understood. Fish utilization of a salt marsh intertidal creek in the Yangtze River estuary was studied based on quarterly sampling surveys in July and November, 2004, and February and May, 2005. Fishes were collected by consecutive day and night samplings using fyke nets during the ebbing spring tides. A total of 25,010 individuals were caught during the study. 17 families and 33 species were documented, and the most species-rich family was Gobiidae. Three species, Synechogobius ommaturus, Chelon haematocheilus and Lateolabrax maculatus together comprised 95.65% of the total catch, which were also the most important commercial fishery species in the Yangtze River estuary. The fish community was dominated by juvenile individuals of estuarine resident species. Time of year significantly affected fish use of salt marshes, but no significant effects of diel periodicity on the fish community were found except for fish sampling in July. These findings indicate that salt marshes in the Yangtze River estuary may play important nursery roles for fish community.

  14. 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.

  15. Spatial and Temporal Variability of Sedimentary Environments in the Hudson River Estuary

    NASA Astrophysics Data System (ADS)

    Slagle, A. L.; Carbotte, S. M.; Nitsche, F. O.; Ryan, W. B.; Bell, R.

    2004-05-01

    Sitting at the interface between marine and terrestrial systems, estuaries are sensitive to natural climatic, sea-level and tectonic changes as well as to anthropogenic impacts. Research on estuarine systems has led to improved understanding of estuarine processes, but relation of those processes to the long-term evolution of estuaries is still uncertain. A geophysical survey funded by the New York State Department of Environmental Conservation resolves details of spatial and temporal variability of sedimentary processes in the Hudson River Estuary. Here we present interpreted sedimentary environments and evidence of past environments for a 30-km stretch of the Lower Hudson River Estuary, between Piermont and Haverstraw Bay. Integration of high-resolution seismic surveys, side-scan sonar imagery and multibeam bathymetry with sediment samples allows differentiation of three distinct sedimentary environments in the estuary: depositional, erosional and dynamic. Modern deposition occurs mainly in Haverstraw Bay on shallow marginal flats bounding the river channel as well as the channel floor. South of Haverstraw Bay, deposition is limited to a local region in a sharp channel bend, and to areas of anthropogenic disturbance. Erosion in the Lower Estuary dominates the broad, shallow western marginal flats in Tappan Zee and Piermont. Man-made and natural obstructions to river flow, such as a relic oyster bed that outcrops on the river bottom in Haverstraw Bay, create local erosional areas. Dynamic environments, incorporating both erosion and deposition, occur where sediment is actively moving through the estuary. Flow-perpendicular sediment waves dominate the channel floor and walls of the Lower Estuary. Dynamic sediment drifts and scouring are associated with man-made constructions, such as the Tappan Zee Bridge and a pipeline crossing the river south of Piermont Pier. Information from sub-bottom seismics and sediment coring provide evidence that sedimentary environments

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

    USGS Publications Warehouse

    Callender, Edward; 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.

  17. The North Atlantic Oscillation influence on the Odra river estuary hydrological conditions

    NASA Astrophysics Data System (ADS)

    Girjatowicz, Józef Piotr

    2007-09-01

    The study focused on the relationships between the North Atlantic Oscillation index and water temperature, number of days with ice, and water level in the Odra river estuaries. Statistically significant relationships occur mainly in the winter period (December-February, December-March, January-March), even up to α = 0.01. The strongest relationships with the NAO index are observed for the water temperature and number of days with ice, mainly in areas with minor water motion (Szczecin Lagoon). The correlation coefficients for water temperature are even >0.80. Only slightly weaker correlation coefficients apply to the NAO relationships to the number of days with ice, especially in the Odra river (in Widuchowa) and in the Pomeranian Bay (in Międzyzdroje). The relationships are deteriorated there by the relatively intensive water motion (ice inflow and outflow). During extreme winters (very harsh or very mild) in the Odra river estuary, local factors, mainly the local southern Baltic Sea atmospheric circulation, negatively affect the NAO relationships to the thermal and ice parameters. The weakest relationships to the NAO index apply to the water level; they are characterized by correlation coefficients <0.60 and weaken inland in the Odra river estuary. During some winters the NAO index relationships to the water level may be distorted by the wind and extreme inflows from the upstream sections of the Odra river.

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. Suwannee river basin and estuary integrated science workshop: September 22-24, 2004 Cedar Key, Florida

    USGS Publications Warehouse

    Katz, Brian; Raabe, Ellen

    2004-01-01

    In response to the growing number of environmental concerns in the mostly pristine Suwannee River Basin and the Suwannee River Estuary system, the States of Florida and Georgia, the Federal government, and other local organizations have identified the Suwannee River as an ecosystem in need of protection because of its unique biota and important water resources. Organizations with vested interests in the region formed a coalition, the Suwannee Basin Interagency Alliance (SBIA), whose goals are to promote coordination in the identification, management, and scientific knowledge of the natural resources in the basin and estuary. To date, an integrated assessment of the physical, biological, and water resources has not been completed. A holistic, multi-disciplinary approach is being pursued to address the research needs in the basin and estuary and to provide supportive data for meeting management objectives of the entire ecosystem. The USGS is well situated to focus on the larger concerns of the basin and estuary by addressing specific research questions linking water supply and quality to ecosystem function and health across county and state boundaries. A strategic plan is being prepared in cooperation with Federal, State, and local agencies to identify and implement studies to address the most compelling research issues and management questions, and to conduct fundamental environmental monitoring studies. The USGS, Suwannee River Water Management District and the Florida Marine Research Institute are co-sponsoring this scientific workshop on the Suwannee River Basin and Estuary to: Discuss current and past research findings, Identify information gaps and research priorities, and Develop an action plan for coordinated and relevant research activities in the future. This workshop builds on the highly successful basin-wide conference sponsored by the Suwannee Basin Interagency Alliance that was held three years ago in Live Oak, Florida. This years workshop will focus on

  3. 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

  4. 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

  5. Assessing the effects of nutrient management in an estuary experiencing climatic change: the Neuse River Estuary, North Carolina.

    PubMed

    Paerl, Hans W; Valdes, Lexia M; Piehler, Michael F; Stow, Craig A

    2006-03-01

    Eutrophication is a serious water quality problem in estuaries receiving increasing anthropogenic nutrient loads. Managers undertaking nutrient-reduction strategies aimed at controlling estuarine eutrophication are faced with the challenge that upstream freshwater segments often are phosphorus (P)-limited, whereas more saline downstream segments are nitrogen (N)-limited. Management also must consider climatic (hydrologic) variability, which affects nutrient delivery and processing. The interactive effects of selective nutrient input reductions and climatic perturbations were examined in the Neuse River Estuary (NRE), North Carolina, a shallow estuary with more than a 30-year history of accelerated nutrient loading and water quality decline. The NRE also has experienced a recent increase in Atlantic hurricanes and record flooding, which has affected hydrology and nutrient loadings. The authors examined the water quality consequences of selective nutrient (P but not N) reductions in the 1980s, followed by N reductions in the 1990s and an increase in hurricane frequency since the mid-1990s. Selective P reductions decreased upstream phytoplankton blooms, but increased downstream phytoplankton biomass. Storms modified these trends. In particular, upstream annual N and P concentrations have decreased during the elevated hurricane period. Increased flushing and scouring from storms and flooding appear to have enhanced nutrient retention capabilities of the NRE watershed. From a management perspective, one cannot rely on largely unpredictable changes in storm frequency and intensity to negate anthropogenic nutrient enrichment and eutrophication. To control eutrophication along the hydrologically variable freshwater-marine continuum, N and P reductions should be applied adaptively to reflect point-source-dominated drought and non-point-source-dominated flood conditions.

  6. 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

  7. 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.

  8. Distribution, sources and ecological risk assessment of PAHs in surface sediments from Guan River Estuary, China.

    PubMed

    He, Xinran; Pang, Yong; Song, Xiaojuan; Chen, Binlin; Feng, Zhihua; Ma, Yuqin

    2014-03-15

    The contamination of surface sediments in Guan River Estuary, China, by polycyclic aromatic hydrocarbons (PAHs) has been fully investigated. Total concentrations of 21 PAHs ranged from 90 to 218 ng/g with an average of 132.7 ng/g, which is relatively low in comparison with other estuaries around the world. PAH concentrations appeared to be positively correlated with clay content and negatively correlated with sediment grain size. Source identification implied that the PAHs originated mainly from pyrolytic sources. However, source patterns may be continuously changed to a petrogenic origin due to the heavy ship traffic and continuous discharge of oily sewage in this area. The PAH levels were also compared with international Sediments Quality Guidelines and Sediments Quality Criteria, and the results indicated low negative effects for most individual PAHs. However, toxic effects related to FLO would occur occasionally in most locations in the estuary.

  9. Water-quality data from continuously monitored sites in the Pamlico and Neuse River estuaries, North Carolina, 1989-90

    USGS Publications Warehouse

    Garrett, Ronald G.; Bales, Jerad

    1991-01-01

    Beginning in April 1989, water quality measurements were made at six sites in or near Pamlico River estuary and at five sites in or near the Neuse River estuary. Measurements taken at 15-minute intervals included near-surface and near-bottom specific conductance; near-surface water temperature; and near-surface, mid-depth, and near-bottom dissolved-oxygen concentrations. Water-quality data obtained from continuously-monitored sites in the Pamlico River estuary and the Neuse River estuary are presented for the period April 1989 through September 1990. Instantaneous values for selected periods are summarized in a series of box plots. Instantaneous maximum and minimum values are also tabulated. Daily mean values of salinity, water temperature, and dissolved-oxygen concentrations for the entire period are presented in tables and graphs.

  10. 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.

  11. Distribution, abundance and productivity of benthic invertebrates at the Berg River estuary, South Africa

    NASA Astrophysics Data System (ADS)

    Kalejta, B.; Hockey, P. A. R.

    1991-08-01

    Twenty-five benthic invertebrate species were identified from samples taken monthly over 17 months at four sites on the Berg River estuary, South Africa. Gastropods and polychaetes dominated the macrofauna in terms of both numbers and biomass. Abundance of the dominant species fluctuated in response to seasonal growth of eelgrass Zostera capensis and filamentous alga Cladophora sp. Differences in distributions of invertebrates on the estuary were attributed to differences in physical properties of the substratum and in vegetation cover. Hydrobia sp., Ceratonereis erythraeensis and C. keiskama were the most important species in terms of biomass and accounted for an average of 75% of total biomass at all study sites. Biomass peaked during the austral winter, early spring and again in autumn. An increase in biomass in winter was due to somatic production, whereas spring and autumn increases were attributed to recruitment of juveniles following reproduction. Mean annual biomass for the whole estuary was 19·36 g m -2, and mean annual production 87·58 g m -2 year -1, yielding a net P/B ratio of 4·52. Production and P/B ratios of invertebrates in estuaries and coastal lagoons at temperate and subtropical latitudes were positively correlated with mean annual ambient temperature and negatively with distance from the equator. Production data are lacking from tropical estuaries.

  12. 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

  13. 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

  14. 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

  15. Nutrients (organic C, P, N, Si) in the eutrophic River Loire (France) and its estuary

    NASA Astrophysics Data System (ADS)

    Meybeck, M.; Cauwet, G.; Dessery, S.; Somville, M.; Gouleau, D.; Billen, G.

    1988-12-01

    The Loire estuary has been surveyed from 1982 to 1985 by 13 isochronous longitudinal profiles realized at low tide. Nutrient (SiO 2, NO 3-, NH 4+, PO 3-4, particulate organic carbon or POC) patterns are very variable depending on the season, the estuarine section [river, upper-inner estuary, upstream of the fresh-water-saline-water interphase FSI, the lower-inner estuary characterized by the high turbidity zone (HTZ), the outer estuary] and the river discharge. Biological processes are dominant. In the eutrophied River Loire (summer pigment > 100 μg l -1), the high algal productivity (algal POC > 3 mg l -1) results in severe depletion of SiO 2, PO 43-, NO 3-. The enormous biomass (55 000 ton algal POC/year) is degraded in the HTZ where bacterial activity is intense. As a result, there is generally a regeneration of dissolved SiO 2 and PO 43-, a marked NH 4+ maximum, while NO 3- is conservative or depleted when the HTZ is nearly anoxic. Other processes can be considered including pollution from fertilizer plans (PO 43-, NH 4+) and from a hydrothermal power plant (NH 4+). In the less turbid outer estuary, nutrients are generally conservative. Major variations of concentrations are observed in the lowest chlorinity section (Cl - < 1 g kg -) and also upstream the FSI, defined here as a 100% increase in Cl -. Nutrient inputs to the ocean are not significantly modified for SiO 2 and NO 2-, but are increased by 70% and 180% for PO 43- and NH 4+ and depleted by 60% for POC. Odd hydrological events, especially some floods, may perturbate or even mask the usual seasonal pattern observed in profiles.

  16. Importance of a winter dinoflagellate-microflagellate bloom in the Patuxent River estuary

    NASA Astrophysics Data System (ADS)

    Sellner, K. G.; Lacouture, R. V.; Cibik, S. J.; Brindley, A.; Brownlee, S. G.

    1991-01-01

    A dense bloom of Katodinium rotundatum was observed in the Patuxent River estuary from December to February 1989. The dinoflagellate dominated phytoplankton densities reaching 10 8 cells l -1 and contributed up to 1900 μgC l -1 in near-surface depths. The bloom maintained a distinct patch extending over 10-25 km of the estuary or approximately one-third to one-half of the total estuary (salinities from 5-13 ppt) and was restricted to regions immediately upriver of the transition between the shallow upriver (3-4 m) and deeper lower estuary (10 m). Daily measurements collected in the primary bloom area at the same time each day in the study area indicated 80- and 120-fold variations in chlorophyll and cell densities from day to day. Densities of potential grazers in the region were high with rotifers, primarily Synchaeta baltica, reaching densities of 1000 l -1 in early winter, and the copepod Eurytemora affinis reaching levels exceeding 1·15 × 10 5 m -3 in February. Estimates of grazing pressure by these planktonic herbivores indicated substantial grazing losses for the bloom, with up to 67% of bloom biomass consumed day -1 in February. Nutrient concentrations and ratios of N/P during the bloom suggested potentially N-limited conditions; bloom demise was coincident with a shift to high N/P ratios and high river flows. These data as well as other historical data suggest that dinoflagellate blooms in the lower Patuxent River estuary could be the primary source of carbon to the system during the winter and supply a large reservoir of labile organic matter to planktonic secondary producers prior to annual spring diatom blooms in the region.

  17. Coastal upwelling supplies oxygen-depleted water to the Columbia River estuary.

    PubMed

    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

  18. Simulation of tidal flow and circulation patterns in the Loxahatchee River Estuary, southeastern Florida

    USGS Publications Warehouse

    Russell, G.M.; Goodwin, C.R.

    1987-01-01

    Results of a two-dimensional, vertically averaged, computer simulation model of the Loxahatchee River estuary show that under typical low freshwater inflow and vertically well mixed conditions, water circulation is dominated by freshwater inflow rather than by tidal influence. The model can simulate tidal flow and circulation in the Loxahatchee River estuary under typical low freshwater inflow and vertically well mixed conditions, but is limited, however, to low-flow and well mixed conditions. Computed patterns of residual water transport show a consistent seaward flow from the northwest fork through the central embayment and out Jupiter Inlet to the Atlantic Ocean. A large residual seaward flow was computed from the North Intracoastal Waterway to the inlet channel. Although the tide produces large flood and ebb flows in the estuary, tide-induced residual transport rates are low in comparison with freshwater-induced residual transport. Model investigations of partly mixed or stratified conditions in the estuary need to await development of systems capable of simulating three-dimensional flow patterns. (Author 's abstract)

  19. 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.

  20. Distribution and sources of polycyclic aromatic hydrocarbons in surface sediments of rivers and an estuary in Shanghai, China.

    PubMed

    Liu, Ying; Chen, Ling; Jianfu, Zhao; Qinghui, Huang; Zhiliang, Zhu; Hongwen, Gao

    2008-07-01

    Concentrations, spatial distribution and sources of 17 polycyclic aromatic hydrocarbons (PAHs) and methylnaphthalene were investigated in surface sediments of rivers and an estuary in Shanghai, China. Total PAH concentrations, excluding perylene, ranged from 107 to 1707 ng/g-dw. Sedimentary PAH concentrations of the Huangpu River were higher than those of the Yangtze Estuary. The concentration of the Suzhou River was close to the average concentration of the Huangpu River. PAHs source analysis suggested that, in the Yangtze Estuary, PAHs at locations far away from cities were mainly from petrogenic sources. At other locations, both petrogenic and pyrogenic inputs were significant. In the Huangpu and Suzhou Rivers, pyrogenic input outweighed other sources. The pyrogenic PAHs in the upper reaches of the Huangpu River were mainly from the incomplete combustion of grass, wood and coal, and those in the middle and lower reaches were from vehicle and vessel exhaust. PMID:18045759

  1. Temporal and spatial variations in nutrient stoichiometry and regulation of phytoplankton biomass in Hong Kong waters: influence of the Pearl River outflow and sewage inputs.

    PubMed

    Xu, Jie; Ho, Alvin Y T; Yin, Kedong; Yuan, Xiangcheng; Anderson, Donald M; Lee, Joseph H W; Harrison, Paul J

    2008-01-01

    In 2001, the Hong Kong government implemented the Harbor Area Treatment Scheme (HATS) under which 70% of the sewage that had been formerly discharged into Victoria Harbor is now collected and sent to Stonecutters Island Sewage Works where it receives chemically enhanced primary treatment (CEPT), and is then discharged into waters west of the Harbor. The relocation of the sewage discharge will possibly change the nutrient dynamics and phytoplankton biomass in this area. Therefore, there is a need to examine the factors that regulate phytoplankton growth in Hong Kong waters in order to understand future impacts. Based on a historic nutrient data set (1986-2001), a comparison of ambient nutrient ratios with the Redfield ratio (N:P:Si=16:1:16) showed clear spatial variations in the factors that regulate phytoplankton biomass along a west (estuary) to east (coastal/oceanic) transect through Hong Kong waters. Algal biomass was constrained by a combination of low light conditions, a rapid change in salinity, and strong turbulent mixing in western waters throughout the year. Potential stoichiometric Si limitation (up to 94% of the cases in winter) occurred in Victoria Harbor due to the contribution of sewage effluent with high N and P enrichment all year, except for summer when the frequency of stoichiometric Si limitation (48%) was the same as P, owing to the influence of the high Si in the Pearl River discharge. In the eastern waters, potential N limitation and N and P co-limitation occurred in autumn and winter respectively, because of the dominance of coastal/oceanic water with low nutrients and low N:P ratios. In contrast, potential Si limitation occurred in spring and a switch to potential N, P and Si limitation occurred in eastern waters in summer. In southern waters, there was a shift from P limitation (80%) in summer due to the influence of the N-rich Pearl River discharge, to N limitation (68%) in autumn, and to N and P co-limitation in winter due to the

  2. Temporal and spatial variations in nutrient stoichiometry and regulation of phytoplankton biomass in Hong Kong waters: influence of the Pearl River outflow and sewage inputs.

    PubMed

    Xu, Jie; Ho, Alvin Y T; Yin, Kedong; Yuan, Xiangcheng; Anderson, Donald M; Lee, Joseph H W; Harrison, Paul J

    2008-01-01

    In 2001, the Hong Kong government implemented the Harbor Area Treatment Scheme (HATS) under which 70% of the sewage that had been formerly discharged into Victoria Harbor is now collected and sent to Stonecutters Island Sewage Works where it receives chemically enhanced primary treatment (CEPT), and is then discharged into waters west of the Harbor. The relocation of the sewage discharge will possibly change the nutrient dynamics and phytoplankton biomass in this area. Therefore, there is a need to examine the factors that regulate phytoplankton growth in Hong Kong waters in order to understand future impacts. Based on a historic nutrient data set (1986-2001), a comparison of ambient nutrient ratios with the Redfield ratio (N:P:Si=16:1:16) showed clear spatial variations in the factors that regulate phytoplankton biomass along a west (estuary) to east (coastal/oceanic) transect through Hong Kong waters. Algal biomass was constrained by a combination of low light conditions, a rapid change in salinity, and strong turbulent mixing in western waters throughout the year. Potential stoichiometric Si limitation (up to 94% of the cases in winter) occurred in Victoria Harbor due to the contribution of sewage effluent with high N and P enrichment all year, except for summer when the frequency of stoichiometric Si limitation (48%) was the same as P, owing to the influence of the high Si in the Pearl River discharge. In the eastern waters, potential N limitation and N and P co-limitation occurred in autumn and winter respectively, because of the dominance of coastal/oceanic water with low nutrients and low N:P ratios. In contrast, potential Si limitation occurred in spring and a switch to potential N, P and Si limitation occurred in eastern waters in summer. In southern waters, there was a shift from P limitation (80%) in summer due to the influence of the N-rich Pearl River discharge, to N limitation (68%) in autumn, and to N and P co-limitation in winter due to the

  3. Comparison of empirical models with intensively observed data for prediction salt intrusion in the Sumjin River estuary, Korea

    NASA Astrophysics Data System (ADS)

    Shaha, D. C.; Cho, Y.-K.

    2009-03-01

    Intensive measurements of salt intrusion in the Sumjin River estuary were taken at high and low waters during both spring and neap tides in each season from August 2004 to April 2007. The estuary demonstrated partially- and well-mixed characteristics during the spring tide and stratified condition during the neap tide. The salt intrusion at high water varied from about 13.39 km in summer 2005 to 25.62 km in autumn 2006. The salt intrusion depended primarily on the freshwater discharges rather than those of spring-neap tidal oscillations. Analysis of three years of observed salinity data indicated that the salt intrusion length scale in the Sumjin River estuary was proportional to the river discharge to the -1/5 power. Five empirical models were applied to the Sumjin River estuary to explore the most suitable as an easy-to-use tool for prediction of the salt intrusion length as functions of the geometry, river discharge and tide. Comparative results showed that the Nguyen and Savenije (2006) model developed under both partially- and well-mixed estuaries yielded the most satisfactory results of all the models studied for computing the salt intrusion length in the Sumjin River estuary. Our study suggests that the model can generate reasonable results for stratified conditions also.

  4. Polycyclic aromatic hydrocarbons in surface sediment of typical estuaries and the spatial distribution in Haihe river basin.

    PubMed

    Liu, Jing L; Zhang, Jing; Liu, Feng; Zhang, Lu L

    2014-05-01

    Polycyclic aromatic hydrocarbons (PAHs) with carcinogenic and mutagenic characteristics have been detected in many estuaries and bays around the world. To detect the contaminated level in typical estuaries in Haihe river basin, China, a comprehensive survey of 16 PAHs in surface sediment has been conducted and an ecological risk assessment has been taken. It showed that Haihe river estuary had the highest concentration, ranging from 92.91 to 15886.00 ng g(-1). And Luan river estuary has the lowest polluted level, ranging from 39.55 to 328.10 ng g(-1). PAHs in sediment were dominated by low and mid molecular weight PAHs in all the sampling sites. Most of the sampling sites in all sampling seasons indicated a rarely happened ecological risk of ΣPAHs, while the S6 in Haihe river estuary was in an occasionally anticipated risk. To illustrate the spatial distribution pattern of PAHs in surface sediment in Haihe river basin, the results were compared with previous research of the research team. Based on data of the comparison, it had been revealed that Haihe river had the most serious PAHs pollution, with an average concentration of 5884.86 ng g(-1), and showed the highest contamination level in all four ecological units. The ΣPAHs concentration showed in a rank of reservoir > estuary > rural area > city.

  5. Abrupt shifts in the fish community of the hydrologically variable upper estuary of the Swan River

    NASA Astrophysics Data System (ADS)

    Kanandjembo, A. N.; Potter, I. C.; Platell, M. E.

    2001-09-01

    Fish were sampled in nearshore, shallow waters (<1·5 m deep) and offshore, deeper waters (2·5-5 m) of the saline lower reaches of the Swan and Canning Rivers, which collectively represent the upper Swan-Canning Estuary, by using seine and gill nets, respectively, in each season between winter 1995 and autumn 1997. Seventeen of the 34 fish species caught during the study spawn in the upper estuaries. These species, which include the semi-anadromous Nematalosa vlaminghi, comprised 50·0% of the number of species and 88·8% of the number of fish in shallow waters and 43·8 and 89·9%, respectively, of those in deeper waters. The two most abundant species in shallow waters, Engraulis australis and N. vlaminghi, contributed 36·0 and 19·6%, respectively, to the total numbers of fish in those waters, and the latter species comprised nearly 50% of the catch in deeper waters. During winter, when freshwater discharge increased sharply and salinities declined precipitously, the number of species and abundance of fish in shallow and deeper waters were generally at their lowest and the species composition was the most discrete. This reflected the downstream movement out of the upper estuary of substantial numbers of individuals of species such as N. vlaminghi, Acanthopagrus butcheri, Amniataba caudavittata, Atherinomorus ogilbyi, Atherinosoma elongata and Craterocephalus mugiloides and the upstream movement into the upper estuary of juvenile Mugil cephalus. The overall fish fauna then changed quite abruptly in spring, when large N. vlaminghi, A. butcheri and A. caudavittata became abundant as they migrated into the upper estuary where they then spawned. During summer and autumn, the fauna in the shallows then changed more gradually through, inter alia, the recruitment of juvenile

  6. Mid-Holocene variability of the East Asian monsoon based on bulk organic δ13C and C/N records from the Pearl River estuary, southern China

    NASA Astrophysics Data System (ADS)

    Yu, F.; Lloyd, J. M.; Zong, Y.; Leng, M. J.; Switzer, A. D.; Yim, W. W.; Huang, G.

    2010-12-01

    Understanding the mid-Holocene dynamics of the East Asian monsoon (EAM) is integral to modelling the Holocene development of the global climate system (Webster et al., 1998). Thus the mid-Holocene EAM history was reconstructed using bulk organic carbon isotopes (δ13C), total carbon to total nitrogen (C/N) ratios and total organic carbon (TOC) from a sediment core (UV1), at a mean resolution of 10 years, from the Pearl River estuary, southern China. Sedimentary δ13C, C/N and TOC from the Pearl River estuary is a good indicator of changes in monsoonal precipitation strength (Zong et al., 2006; Yang et al., 2010), eg sediments buried during a period of high precipitation exhibit a high proportion of terrigenous sediments, and have low δ13C and high C/N, and vice versa (Yu et al., 2010). Results suggest a general decreasing trend in monsoonal precipitation from 6650-2215 cal yr BP due to the weakening insolation over northern hemisphere most likely related to the current precession circle (An, 2000). Superimposed on this trend are apparent dry-wet oscillations at centennial to millennial timescales most likely in response to solar activity. Mismatch between δ13C and results from the Dongge Cave in southern China at millennial-timescale oscillations (Wang et al., 2005), may indicate that the δ13C from the Pearl River estuary reveals changes in precipitation in a broader area than the δ18O from Dongge Cave does. Reference An Z (2000) The history and variability of the East Asian paleomonsoon climate. Quaternary Science Reviews 19: 171-187. Wang Y, Cheng H, Edwards RL, He Y, Kong X, An Z, Wu J, Kelly MJ, Dykoski CA and Li X (2005) The Holocene Asian Monsoon: Links to Solar Changes and North Atlantic Climate. Science 308: 854-857. Webster PJ, Magaña VO, Palmer TN, Shukla J and Tomas RA (1998) Monsoons: Processes, predictability, and the prospects for prediction. Journal of Geophysical Research 103(C7): 14451-14510. Yang S, Tang M, Yim WWS, Zong Y, Huang G, Switzer

  7. Mid-Holocene variability of the East Asian monsoon based on bulk organic δ13C and C/N records from the Pearl River estuary, southern China

    NASA Astrophysics Data System (ADS)

    Yu, F.; Zong, Y.; Lloyd, J. M.; Leng, M. J.; Switzer, A. D.; Yim, W. W.; Huang, G.

    2012-12-01

    Understanding the mid-Holocene dynamics of the East Asian monsoon (EAM) is integral to modelling the Holocene development of the global climate system (Webster et al., 1998). Thus the mid-Holocene EAM history was reconstructed using bulk organic carbon isotopes (δ13C), total carbon to total nitrogen (C/N) ratios and total organic carbon (TOC) from a sediment core (UV1), at a mean resolution of 7-10 years, from the Pearl River estuary, southern China. Sedimentary δ13C, C/N and TOC from the Pearl River estuary is a good indicator of changes in monsoonal precipitation strength (Zong et al., 2006; Yang et al., 2010; Yu et al., 2010), eg sediments buried during a period of high precipitation exhibit a high proportion of terrigenous sediments, and have low δ13C and high C/N, and vice versa (Yu et al., 2010). Results suggest a general decreasing trend in monsoonal precipitation from 6650 to 2215 cal yr BP because of the weakening Northern Hemisphere insolation most likely related to the current precession circle (An, 2000). Superimposed on this trend are apparent dry-wet oscillations at centennial to millennial timescales most likely in response to solar activity. Mismatch between δ13C and results from the Dongge Cave in southern China at millennial-timescale oscillations (Wang et al., 2005), may indicate that the δ13C from the Pearl River estuary reveals changes in precipitation in a broader area than the δ18O from Dongge Cave does. Reference An Z (2000) The history and variability of the East Asian paleomonsoon climate. Quaternary Science Reviews 19: 171-187. Wang Y, Cheng H, Edwards RL, He Y, Kong X, An Z, Wu J, Kelly MJ, Dykoski CA and Li X (2005) The Holocene Asian Monsoon: Links to Solar Changes and North Atlantic Climate. Science 308: 854-857. Webster PJ, Magaña VO, Palmer TN, Shukla J and Tomas RA (1998) Monsoons: Processes, predictability, and the prospects for prediction. Journal of Geophysical Research 103(C7): 14451-14510. Yang S, Tang M, Yim WWS, Zong

  8. [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.

  9. 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.

  10. 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.

  11. 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.

  12. Spatial distribution of copepods along the salinity gradient of Perai river estuary, Penang, Malaysia.

    PubMed

    Johan, I; Maznah, W O Wan; Mashhor, M; Abu Hena, M K; Amin, S M N

    2012-07-01

    Investigation on copepod communities in Perai river estuary was conducted from November 2005 to May 2006. Five stations were established for monthly sampling and were located from the river mouth to the upper reaches of the river. Copepod samples were collected from vertical tows using a standard zooplankton net. The Perai river estuary was slightly stratified and salinity decreases significantly from the mouth of the river towards the upper reaches of the river. A total of 28 species of copepods were recorded and comprised of 14 families, Paracalanidae, Oithonidae, Corycaeidae, Acartiidae, Calanidae, Centropagidae, Eucalanidae, Pontellidae, Pseudodiaptomidae, Tortanidae, Ectinosomatidae, Euterpinidae, Clausidiidae and Cyclopidae. A total of 10 species showed high positive affiliation towards salinity (R > 0.60), Acartia spinicauda, Euterpina acutifrons, Microsetella norvegica, Oithona nana, Oithona simplex, Paracalanus crassirostris, Paracalanus elegans, Paracalanus parvus, Pseudodiaptomus sp. and Hemicyclops sp. The copepod species Pseudodiaptomus dauglishi were negatively affiliated towards salinity (R = -0.71). The copepod assemblages classified into two distinct groups according to salinity regimes, euryhaline-polyhaline group (25 marine affiliated species) and oligohaline-mesohaline group (3 freshwater affiliated species).

  13. 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).

  14. 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.

  15. 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

  16. Analysis of change of red tide species in Yodo River estuary by the numerical ecosystem model.

    PubMed

    Hayashi, Mitsuru; Yanagi, Tetsuo

    2008-01-01

    Occurrence number of red tides in Osaka Bay in Japan is more than 20 cases every year. Diatom red tide was dominant in Osaka Bay, but the non-diatom red tide was dominant in early 1990s. Therefore, the material cycling in Yodo River estuary in Osaka Bay during August from 1991 to 2000 was analyzed by using the numerical ecosystem model and field observation data to clarify the reasons of change in red tide species. Year-to-year variation in calculated concentration ratio of diatom to non-diatom corresponds to the variation in observed ratio of red tide days of diatom to non-diatom. Limiting nutrient of primary production is phosphate over the period. Diatom dominated from 1991 to 1993, but it was difficult for non-diatom to grow due to the limitation by physical condition. Non-diatom was able to grow because of good physical and nutrient conditions from 1994 to 1996. And diatom dominated again under the good physical condition, and phosphorus supply was not enough for non-diatom to grow from 1998 to 2000. Phosphate concentration in the lower layer of Yodo River estuary was important to the variation in red tide species in the upper layer of Yodo River estuary.

  17. 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.

  18. 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.

  19. Assessment of dissolved heavy metal in the Yangtze River estuary and its adjacent sea, China.

    PubMed

    An, Qiang; Wu, Yanqing; Wang, Jinhui; Li, Zhien

    2010-05-01

    The purpose of this paper is to determine the concentrations of dissolved heavy metals namely mercury (Hg), lead (Pb), cadmium (Cd), and copper (Cu) and to investigate the relationships between nutrients (nitrate-nitrogen and phosphate) and dissolved heavy metals. For this purpose, the concentrations of dissolved heavy metals were measured through 51 voyages form 1984 to 2006 in the Yangtze river estuary and its adjacent sea. Results analysis showed that dissolved heavy metals were not the main pollutants in the Yangtze river estuary, and the main source of heavy metal contamination was industrial wastewater from terrestrial pollution during the past 20 years. Heavy metal values showed significant abundance in the south branch of the Yangtze River estuary and Hangzhou Bay. In addition, Pb showed negative correlation with nutrients, while the positive correlations between Hg, Cd, and nutrients were shown. The obtained molar ratios, DeltaCd/DeltaN = 1.68 x 10(-5) and DeltaCd/DeltaP = 1.66 x 10(-4), are close to those in plankton, showing the biogeochemical behavior and process of dissolved cadmium.

  20. Comparison of empirical models with intensively observed data for prediction of salt intrusion in the Sumjin River estuary, Korea

    NASA Astrophysics Data System (ADS)

    Shaha, D. C.; Cho, Y.-K.

    2009-06-01

    Performance of empirical models has been compared with extensively observed data to determine the most suitable model for prediction of salt intrusion in the Sumjin River estuary, Korea. Intensive measurements of salt intrusion were taken at high and low waters during both spring and neap tide in each season from August 2004 to April 2007. The stratification parameter varied with the distance along the estuary, tidal period and freshwater discharge, indicating that the Sumjin River estuary experiences a transition from partially- or well-mixed during spring tide to stratified during neap tide. The salt intrusion length at high water varied from 13.4 km in summer 2005 to 25.6 km in autumn 2006. The salt intrusion mostly depends on the freshwater discharge rather than spring-neap tidal oscillation. Analysis of three years observed salinity data indicates that the scale of the salt intrusion length in the Sumjin River estuary is proportional to the river discharge to the -1/5 power. Four empirical models have been applied to the Sumjin River estuary to explore the most suitable model for prediction of the salt intrusion length. Comparative results show that the Nguyen and Savenije (2006) model, developed under both partially- and well-mixed estuaries, performs best of all models studied (relative error of 4.6%). The model was also applied under stratified neap tide conditions, with a relative error of 5.2%, implying applicability of this model under stratified conditions as well.

  1. Suspended sediment transport in the freshwater reach of the Hudson river estuary in eastern New York

    USGS Publications Warehouse

    Wall, G.R.; Nystrom, E.A.; Litten, S.

    2008-01-01

    Deposition of Hudson River sediment into New York Harbor interferes with navigation lanes and requires continuous dredging. Sediment dynamics at the Hudson estuary turbidity maximum (ETM) have received considerable study, but delivery of sediment to the ETM through the freshwater reach of the estuary has received relatively little attention and few direct measurements. An acoustic Doppler current profiler was positioned at the approximate limit of continuous freshwater to develop a 4-year time series of water velocity, discharge, suspended sediment concentration, and suspended sediment discharge. This data set was compared with suspended sediment discharge data collected during the same period at two sites just above the Hudson head-of-tide (the Federal Dam at Troy) that together represent the single largest source of sediment entering the estuary. The mean annual suspended sediment-discharge from the freshwater reach of the estuary was 737,000 metric tons. Unexpectedly, the total suspended sediment discharge at the study site in November and December slightly exceeded that observed during March and April, the months during which rain and snowmelt typically result in the largest sediment discharge to the estuary. Suspended sediment discharge at the study site exceeded that from the Federal Dam, even though the intervening reach appears to store significant amounts of sediment, suggesting that 30-40% of sediment discharge observed at the study site is derived from tributaries to the estuary between the Federal Dam and study site. A simple model of sediment entering and passing through the freshwater reach on a timescale of weeks appears reasonable during normal hydrologic conditions in adjoining watersheds; however, this simple model may dramatically overestimate sediment delivery during extreme tributary high flows, especially those at the end of, or after, the "flushing season" (October through April). Previous estimates of annual or seasonal sediment delivery

  2. 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

  3. 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

  4. Estimation of groundwater and nutrient fluxes to the Neuse River estuary, North Carolina

    USGS Publications Warehouse

    Spruill, T.B.; Bratton, J.F.

    2008-01-01

    A study was conducted between April 2004 and September 2005 to estimate groundwater and nutrient discharge to the Neuse River estuary in North Carolina. The largest groundwater fluxes were observed to occur generally within 20 m of the shoreline. Groundwater flux estimates based on seepage meter measurements ranged from 2.86??108 to 4.33??108 m3 annually and are comparable to estimates made using radon, a simple water-budget method, and estimates derived by using Darcy's Law and previously published general aquifer characteristics of the area. The lower groundwater flux estimate (equal to about 9 m3 s-1), which assumed the narrowest groundwater discharge zone (20 m) of three zone widths selected for an area west of New Bern, North Carolina, most closely agrees with groundwater flux estimates made using radon (3-9 m3 s-1) and Darcy's Law (about 9 m3 s-1). A groundwater flux of 9 m 3 s-1 is about 40% of the surface-water flow to the Neuse River estuary between Streets Ferry and the mouth of the estuary and about 7% of the surface-water inflow from areas upstream. Estimates of annual nitrogen (333 tonnes) and phosphorus (66 tonnes) fluxes from groundwater to the estuary, based on this analysis, are less than 6% of the nitrogen and phosphorus inputs derived from all sources (excluding oceanic inputs), and approximately 8% of the nitrogen and 17% of the phosphorus annual inputs from surface-water inflow to the Neuse River estuary assuming a mean annual precipitation of 1.27 m. We provide quantitative evidence, derived from three methods, that the contribution of water and nutrients from groundwater discharge to the Neuse River estuary is relatively minor, particularly compared with upstream sources of water and nutrients and with bottom sediment sources of nutrients. Locally high groundwater discharges do occur, however, and could help explain the occurrence of localized phytoplankton blooms, submerged aquatic vegetation, or fish kills. ?? 2008 Coastal and Estuarine

  5. 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.

  6. 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.

  7. Humpback Dolphins in Hong Kong and the Pearl River Delta: Status, Threats and Conservation Challenges.

    PubMed

    Karczmarski, Leszek; Huang, Shiang-Lin; Or, Carmen K M; Gui, Duan; Chan, Stephen C Y; Lin, Wenzhi; Porter, Lindsay; Wong, Wai-Ho; Zheng, Ruiqiang; Ho, Yuen-Wa; Chui, Scott Y S; Tiongson, Angelico Jose C; Mo, Yaqian; Chang, Wei-Lun; Kwok, John H W; Tang, Ricky W K; Lee, Andy T L; Yiu, Sze-Wing; Keith, Mark; Gailey, Glenn; Wu, Yuping

    2016-01-01

    In coastal waters of the Pearl River Delta (PRD) region, the Indo-Pacific humpback dolphin (Sousa chinensis) is thought to number approximately 2500 individuals. Given these figures, the putative PRD population may appear strong enough to resist demographic stochasticity and environmental pressures. However, living in close proximity to the world's busiest seaport/airport and several densely populated urban centres with major coastal infrastructural developments comes with challenges to the long-term survival of these animals. There are few other small cetacean populations that face the range and intensity of human-induced pressures as those present in the PRD and current protection measures are severely inadequate. Recent mark-recapture analyses of the animals in Hong Kong waters indicate that in the past two decades the population parameters have not been well understood, and spatial analyses show that only a very small proportion of the dolphins' key habitats are given any form of protection. All current marine protected areas within the PRD fail to meet a minimum habitat requirement that could facilitate the population's long-term persistence. Demographic models indicate a continuous decline of 2.5% per annum, a rate at which the population is likely to drop below the demographic threshold within two generations and lose 74% of the current numbers within the lifespan of three generations. In Hong Kong, the case of humpback dolphins represents a particularly explicit example of inadequate management where a complete revision of the fundamental approach to conservation management is urgently needed.

  8. Humpback Dolphins in Hong Kong and the Pearl River Delta: Status, Threats and Conservation Challenges.

    PubMed

    Karczmarski, Leszek; Huang, Shiang-Lin; Or, Carmen K M; Gui, Duan; Chan, Stephen C Y; Lin, Wenzhi; Porter, Lindsay; Wong, Wai-Ho; Zheng, Ruiqiang; Ho, Yuen-Wa; Chui, Scott Y S; Tiongson, Angelico Jose C; Mo, Yaqian; Chang, Wei-Lun; Kwok, John H W; Tang, Ricky W K; Lee, Andy T L; Yiu, Sze-Wing; Keith, Mark; Gailey, Glenn; Wu, Yuping

    2016-01-01

    In coastal waters of the Pearl River Delta (PRD) region, the Indo-Pacific humpback dolphin (Sousa chinensis) is thought to number approximately 2500 individuals. Given these figures, the putative PRD population may appear strong enough to resist demographic stochasticity and environmental pressures. However, living in close proximity to the world's busiest seaport/airport and several densely populated urban centres with major coastal infrastructural developments comes with challenges to the long-term survival of these animals. There are few other small cetacean populations that face the range and intensity of human-induced pressures as those present in the PRD and current protection measures are severely inadequate. Recent mark-recapture analyses of the animals in Hong Kong waters indicate that in the past two decades the population parameters have not been well understood, and spatial analyses show that only a very small proportion of the dolphins' key habitats are given any form of protection. All current marine protected areas within the PRD fail to meet a minimum habitat requirement that could facilitate the population's long-term persistence. Demographic models indicate a continuous decline of 2.5% per annum, a rate at which the population is likely to drop below the demographic threshold within two generations and lose 74% of the current numbers within the lifespan of three generations. In Hong Kong, the case of humpback dolphins represents a particularly explicit example of inadequate management where a complete revision of the fundamental approach to conservation management is urgently needed. PMID:26790887

  9. 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

  10. 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

  11. 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.

  12. Integrated modelling of faecal contamination in a densely populated river-sea continuum (Scheldt River and Estuary).

    PubMed

    de Brauwere, Anouk; Gourgue, Olivier; de Brye, Benjamin; Servais, Pierre; Ouattara, Nouho Koffi; Deleersnijder, Eric

    2014-01-15

    In order to simulate the long-term (months-years) median Escherichia coli distributions and variations in the tidal Scheldt River and Estuary, a dedicated module was developed for the Second-generation Louvain-la-Neuve Ice-ocean Model (SLIM, www.climate.be/slim). The resulting model (SLIM-EC2) presents two specific and new features compared to the older SLIM-EC model version. The first is that the E. coli concentrations in the river are split in three fractions: the free E. coli in the water column, the ones attached to suspended solids and those present in the bottom sediments, each with their own transport, decay and settling-resuspension dynamics. The bacteria attached to particles can settle and survive on the bottom, where they can be brought back in the water column during resuspension events. The second new feature of the model is that it is coupled to the catchment model SENEQUE-EC, which thus provides upstream boundary conditions to SLIM-EC2. The result is an integrated and multi-scale model of the whole Scheldt drainage network from its source down to the Belgian/Dutch coastal zone. This new model reproduces the long-term median E. coli concentration along the Scheldt River and Estuary. An extensive sensitivity study is performed demonstrating the relative robustness of the model with respect to the chosen parameterisations. In addition to reproducing the observed E. coli concentrations in 2007-2008 at various stations, two extreme wastewater management scenarios were considered. Overall, there is no doubt that the Scheldt Estuary acts as a cleaning filter of faecal contamination originating from large Belgian cities. As a result, at the mouth of the Scheldt Estuary E. coli concentration is negligible in all investigated conditions. PMID:23999159

  13. Consumption processes and food web structure in the Columbia River Estuary

    NASA Astrophysics Data System (ADS)

    Simenstad, Charles A.; Small, Lawrence F.; David McIntire, C.

    Consumption processes at several trophic levels tend to coverage in the central (estuarine-mixing) region of the Columbia River estuary, where living and dentrital food resources are entrained within the energy null of the turbidity maximum zone. Primary consumers in this region are generalist and omnivorous feeders, capable of exploiting both autotrophic and heterotrophic food web pathways. In the presence of higher standing stocks of their prey resources, feeding by secondary and tertiary consumers is also concentrated, or more effective, in the estuarine mixing region of the estuary. During the 1980-1981 studies of the estuary, total consumer (metazoan) production averaged 5.5g C m -2 within the estuary. Of the estimated 15 x 10 3mt Cyy -1 attributed to primary consumption in the water column, 83% was the result of suspension-feeding pelagic zooplankton. In comparison to grazing on phytoplankton, it was estimated that approximately 84% of primary consumption in the water column was based on suspended detritus and, presumably, associated microbiota. Endemic primary,consumers, principally epibenthic crustaceans such as the calanoid copepod Eurytemora affinis, the harpacticoid copepod Scottolana canadensis, and the crangonid shrimp Crangon franciscorum, accounted for a high proportion of the consumption of suspended particles. Wertland herbivores inhabiting the estuary's extensive marshes, on the other hand, were estimated to account for only 2 to 17% of total estuarine primary consumption. Trophic linkages to secondary and tertiary consumers were more evenly apportioned among pelagic fishes, motile macroinvertebrates, and benthic infauna. High, comparatively unknown fluxes of migratory or wide-ranging tertiary consumers, such as piscivorous birds, seals and sea lions, made estimation of their annual consumption rates in the estuary highly tenuous. The physical processes of mixing and stratification, sediments accretion and erosion, and salinity intrusion appear to

  14. Hydrodynamics in the Yellow River Estuary via radium isotopes: Ecological perspectives

    NASA Astrophysics Data System (ADS)

    Xu, Bochao; Burnett, William; Dimova, Natasha; Diao, Shaobo; Mi, Tiezhu; Jiang, Xueyan; Yu, Zhigang

    2013-09-01

    We used radium isotopes as tracers to characterize coastal hydrodynamics and submarine groundwater discharge (SGD) in the Yellow River Estuary in order to assess the ecological effects in one of the most turbid estuaries in the world. Based on apparent water ages calculated by 224Ra/223Ra activity ratios, we found that the river plume flowed mainly southeast at a flow rate of 5-7 km d-1, while a small portion of the river plume was diverted northeast to the central Bohai Sea at a flow rate of less than 2 km d-1. We estimate that with this flow regime, nutrients would be consumed within about two weeks mostly by microplankton and nanoplankton near shore, and picoplankton further offshore to support an average primary production of 0.14 g C m-2 d-1. We then used a 226Ra mass balance model to quantify the SGD flux in the study area. The estimated SGD flux was 1.3×109 m3 d-1 with a range of 2.8×108-3.0×109 m3 d-1. Even the minimum SGD value was about 3 times higher than the Yellow River discharge at that time. The SGD input of dissolved nutrients was shown to be very important to the estuarine nutrient budget, at least 5 times higher than river input. Sediment regeneration of nutrients proved to be very small relative to the SGD flux in this region.

  15. 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.

  16. Continuous resistivity profiling data from the upper Neuse River Estuary, North Carolina, 2004-2005

    USGS Publications Warehouse

    Cross, VeeAnn A.; Bratton, John F.; Bergeron, Emile M.; Meunier, Jeff K.; Crusius, John; Koopmans, Dirk

    2006-01-01

    The Neuse River Estuary in North Carolina has suffered impacts of eutrophication in recent years. As part of a larger project to better constrain nutrient budgets in the estuary, field investigations were performed to study occurrence and discharge of fresh and brackish ground water and nutrients beneath the estuary itself (fig. 1). A Continuous Resistivity Profiling (CRP) system (Manheim and others, 2004) was used to map the depth of the freshwater-saltwater interface (FSI) in sub-estuarine groundwater. This study area serves as a typological representation of a submarine groundwater environment characteristic of a shallow estuary in a wide coastal plain that has not experienced glaciation. Similar settings extend from New Jersey to Georgia, and along the Gulf of Mexico in the U.S. This report archives 29 lines of data collected during 2004 and 2005 surveys representing almost 210 km of survey lines. These data are further explained in the Data Processing section of the report and previews available of the processed data are available.

  17. 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.

  18. 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.

  19. Bedform signatures of channel erosion: examples from the Delaware and Hudson River estuaries

    NASA Astrophysics Data System (ADS)

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

    2003-04-01

    Bedforms are the most ubiquitous and accessible indicators of sediment-transport conditions in river-estuaries and shed light on processes and patterns of deposition and erosion over large spatial scales. Results of recent observational studies in the Delaware and Hudson River estuaries (Mid-Atlantic Region U.S.A.) permit a provisional systemization of bedform morphologies associated with cohesive strata erosion in tidal channels. An understanding of mechanisms and scales of erosion is necessary to predict the long-term fate of pollutants buried within urbanized sections of these estuaries. Side-scan sonographs, high-resolution multibeam bathymetry, and extensive sedimentological data collectively reveal at least two common signatures of channel erosion: (1) depositional bedforms, including flow-perpendicular, sand and gravel ribbons, and flow-parallel, sediment trails and furrows; and (2) sculpted forms, including cohesive sediment ripples and waves, scour depressions, and terraces. Although the ribbons and trails are created through bedload deposition, because these forms are observed only where the channels are deepening on the long term (as per historical bathymetric data), they are in fact manifestations of net erosion. Both depositional and sculpted bedforms exhibit marked cross-channel variations in distribution, presumably due to flood-ebb current asymmetry and transverse gradients in sediment transport. Additionally, sediment supply influences the along-channel continuity of depositional forms, which ranges from patchy (sediment limited) to continuous (sediment rich). Coring observations of sands and shell fragments in the vicinity of the sculpted forms suggest that abrasion is an agent of bed reworking. Indeed, these findings confirm that corrasion is an important mechanism of erosion in muddy estuarine channels, though this elusive process is generally not considered in models of channel morphodynamics. Bedforms are useful for recognizing channel

  20. 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.

  1. 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)

  2. Chemical and microbiological qualities of The East River (Dongjiang) water, with particular reference to drinking water supply in Hong Kong.

    PubMed

    Ho, K C; Chow, Y L; Yau, J T S

    2003-09-01

    Currently, about 80% of drinking water in Hong Kong is abstracted from The East River (Dongjiang) that is located in the mainland side of China. Literature records and monitoring results of 2000-2001 confirmed that the lower section of the Dongjiang had been contaminated by organic and inorganic pollutants. Statistical analyses showed that the increases of total cadmium, copper and zinc in the surface layer of sediment of Hong Kong reservoirs from 1994 to 2001 were positively correlated (significant at p<0.05) with those in the surface layer of sediments of the lower Dongjiang. Recent microbiological survey revealed that pathogens such as Salmonella spp., Vibro spp., Giardia lamblia and Cryptosporidium parvum appeared occasionally in water samples of the Dongjiang and Hong Kong reservoirs. While analytical results found that currently most of the heavy metals, trace organics and microbes were removed by the drinking water treatment plants in Hong Kong, the long-term health risk of drinking water contamination should not be overlooked. The Water Supplies Department of Hong Kong is recommended to intensify its water quality monitoring program to cover pathogenic bacteria and parasites in watercourses and reservoirs. PMID:12867174

  3. Spatial assessment of water quality using chemometrics in the Pearl River Estuary, China

    NASA Astrophysics Data System (ADS)

    Wu, Meilin; Wang, Youshao; Dong, Junde; Sun, Fulin; Wang, Yutu; Hong, Yiguo

    2016-09-01

    A cruise was commissioned in the summer of 2009 to evaluate water quality in the Pearl River Estuary (PRE). Chemometrics such as Principal Component Analysis (PCA), Cluster analysis (CA) and Self-Organizing Map (SOM) were employed to identify anthropogenic and natural influences on estuary water quality. The scores of stations in the surface layer in the first principal component (PC1) were related to NH4-N, PO4-P, NO2-N, NO3-N, TP, and Chlorophyll a while salinity, turbidity, and SiO3-Si in the second principal component (PC2). Similarly, the scores of stations in the bottom layers in PC1 were related to PO4-P, NO2-N, NO3-N, and TP, while salinity, Chlorophyll a, NH4-N, and SiO3-Si in PC2. Results of the PCA identified the spatial distribution of the surface and bottom water quality, namely the Guangzhou urban reach, Middle reach, and Lower reach of the estuary. Both cluster analysis and PCA produced the similar results. Self-organizing map delineated the Guangzhou urban reach of the Pearl River that was mainly influenced by human activities. The middle and lower reaches of the PRE were mainly influenced by the waters in the South China Sea. The information extracted by PCA, CA, and SOM would be very useful to regional agencies in developing a strategy to carry out scientific plans for resource use based on marine system functions.

  4. 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.

  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. Variation of phytoplankton community structure from the Pearl River estuary to South China Sea.

    PubMed

    Jiang, Zhao-Yu; Wang, You-Shao; Cheng, Hao; Sun, Cui-Ci; Wu, Mei-Lin

    2015-10-01

    The Pearl River is located in the northern part of South China Sea. The environment of the Pearl River estuary (PRE) is significantly impacted by nutrients from anthropogenic activities. Along the anthropogenic pollution gradient from the PRE to South China Sea, the phylogenetic diversity and biomass of phytoplankton was examined in relation to physic-chemical variables. The richness of rbcL gene was higher in the open sea than the estuary, while the concentration of chlorophyll a (Chl a) was higher in the estuary than in the open sea. The cluster analysis of the sequences data resulted in seven phytoplankton community types and the dominant species of phytoplankton changed from Cryptophytes and Diatoms to Prymnesiophytes and Diatoms along the gradient. The community structure of phytoplankton was shaped by nutrients and salinity. The phytoplankton biomass was significantly positively affected by phosphorus, nitrite and ammonium (P < 0.01) but negatively by salinity (P < 0.05); the phytoplankton diversity was highly positively affected by salinity (P < 0.05) but negatively by silicate and nitrate (P < 0.01; P < 0.05, respectively). Anthropogenic activities played a critical role in the phytoplankton distribution and biomass of the study area. Further research is necessary to reveal the influence mechanism of environmental factors on the phytoplankton.

  7. 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.

  8. 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

  9. 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).

  10. 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

  11. 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.

  12. 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 ...

  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. 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.

  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. 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

  17. Influence of Environmental Variables on the Distribution of Macrobenthos in the Han River Estuary, Korea

    NASA Astrophysics Data System (ADS)

    Yu, Ok Hwan; Lee, Hyung-Gon; Lee, Jae-Hac

    2012-12-01

    We compared environmental effects on the macrobenthic community of the Han River Estuary in summer, when freshwater input from the Han River increased, and in spring, when freshwater input decreased. Field samples were taken from the upper region of the Shingok reservoir to the southern area of Ganghwado at 18 sampling sites after rainy (August 2006) and dry (March 2007) seasons. Macrobenthic fauna were collected using a Van Veen Grab (0.025 m2 and 0.1 m2) and environmental factors were measured simultaneously. Dominant species of macrobenthic fauna and the macrobenthic community were divided into two areas, the area of the Han River with no salinity (< 0.1 psu) and the southern part of Ganghwado with salinity (> 20 psu). The dominant species Byblis japonicus appeared at Junruri in the dry season. The distributions of two polychaetes, Hediste japonica and Nephtys caeca, were divided into the lower and upper areas of the Singok submerged weir. BIO-ENV (the matching of biotic to environmental patterns) analysis revealed that salinity was the most important factor affecting macrobenthic communities in the Han River Estuary, with other factors such as sediment grain size, bottom dissolved oxygen, and total organic carbon of sediment being secondary.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. FLOW PATTERN AND SUSPENDED SEDIMENT TRANSPORT AROUND SPUR DIKES IN THE KIKUCHI RIVER ESTUARY

    NASA Astrophysics Data System (ADS)

    Ohmoto, Terunori; Hirakawa, Ryuichi

    A series of spur dikes was constructed to reinforce an embankment at bends in the lower reach of the Kikuchi River. In recent years, eutrophicated fine sediment accumulation around spur dikes has caused a serious problem in estuary ecosystem. Therefore, Ministry of Land, Infrastructure and Transport has developed the renaturalization project of sand beach in the estuary. In this study, we have particularly investigated flow patterns and fine sediment transport around these spur dikes by using Stream-pro Acoustic Doppler Current Profiler (ADCP) and radio-controlled model boat equipped with Workhorse ADCP in the period of spring tide. The results show that these spur dikes weakened flow and SS transport in the concave, and strengthened them in the convex of the bend. In addition, fine sediment accumulation were discussed through streamwise distribution of SS transport in both cases of flood and ebb tide.

  3. 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.

  4. Mercury in the Mackenzie River delta and estuary: concentrations and fluxes during open-water conditions.

    PubMed

    Graydon, Jennifer A; Emmerton, Craig A; Lesack, Lance F W; Kelly, Erin N

    2009-04-01

    Estimates of mercury (Hg) loadings to the Arctic Ocean from circumpolar rivers have not considered biogeochemical changes that occur when river water is temporarily stored in large deltas (delta effect). There are also few data describing Hg changes across the freshwater-saltwater transition zone (FSTZ) of these rivers. We assessed temporal changes in unfiltered total mercury (THg) and methylmercury (MeHg) concentrations during open-water 2004 in the Mackenzie River upstream of the Mackenzie River delta, and in 6 floodplain lakes across an elevation gradient. These data were used to calculate Hg fluxes from the Mackenzie River and to evaluate a delta effect on Hg using an estimate of delta river water storage and a mixing analysis. Mean THg concentrations were highest in river water (9.17+/-5.51 ng/L) and decreased up the lake elevation gradient. Mean MeHg concentrations were highest in lakes periodically connected to the river (0.213+/-0.122 ng/L) and MeHg concentrations in elevated lakes showed a mid-summer peak. Results from the mixing analysis showed that the delta effect may be large enough to affect Hg loadings to the Arctic Ocean. THg concentrations exiting the delta (10.2 ng/L) were 16% lower than those entering (12.1 ng/L), whereas MeHg showed little change. We calculated 2.5-month (open-water) THg and MeHg fluxes from the Mackenzie River of 1208 and 8.4 kg. These fluxes are similar in magnitude to previous annual estimates in the arctic literature suggesting that previously published annual Hg fluxes from the Mackenzie River may be large underestimates. We also assessed changes in Mackenzie River water THg and MeHg concentrations as it crossed the FSTZ during an open-water cruise. THg decreased non-conservatively across the estuary from 3.8-0.6 ng/L, possibly due to mixing and particle settling. MeHg concentrations were variable and near detection. Our results show that the Mackenzie River estuary is a dynamic environment and may have important controls

  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. 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.

  7. 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.

  8. Association of plutonium with sediments from the Ob and Yenisey Rivers and Estuaries.

    PubMed

    Skipperud, Lindis; Brown, Justin; Fifield, L Keith; Oughton, Deborah H; Salbu, Brit

    2009-04-01

    The present study applied sequential extraction techniques to investigate the binding and mobility of plutonium (Pu) in sediments from the rivers and estuaries of the Ob and Yenisey. As a study site, the Ob and Yenisey are particularly interesting as both rivers have weapons-grade Pu sources in their catchment areas, including the Russian Pu production and reprocessing plants at Mayak, Tomsk-7 and Krashnoyarsk, and the Semipalantinsk nuclear weapons testing site in Kazakhstan. Plutonium activity and (240)Pu/(239)Pu ratios were determined using accelerator mass spectrometry (AMS). Sequential extractions showed that between 47 and 80% of the Pu in Yenisey River sediments and 35-53% of the Pu in soils around the Techa River are mobilized with weak oxidising agents, which can indicate that Pu is bound to organic material. In contrast, Pu in Ob and Yenisey Estuarine sediments was more strongly bound, with 60-100% being found in the HNO(3)-extractable fraction. This change in speciation could reflect either that Pu bound to organic material in the Techa and Yenisey River sediments becomes more fixed to the sediments with time, or that organic-bound Pu is mobilized and released to the water when the sediments encounter the more saline water of the Ob and Yenisey estuaries. In general, (240)Pu/(239)Pu ratios were relatively consistent between different extraction fractions, although, in whole sediments, an increase in ratio was observed with distance from the source. This reflects the increased influence of weapon fallout from catchment runoff within the river systems, as compared to the weapons-grade sources close to the production and reprocessing plants. Knowledge of Pu speciation in the Ob and Yenisey Rivers, and the processes controlling its behaviour in estuarine systems, can improve predictions of its transfer and subsequent environmental impact to Arctic Seas. PMID:19157655

  9. 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

  10. Water-quality data from continuously monitored sites in the Pamlico and Neuse River estuaries, North Carolina, 1991-92

    USGS Publications Warehouse

    Garrett, R.G.

    1994-01-01

    Water-quality measurements were made at six sites in or near North Carolina?s Pamlico River estuary and at five sites in or near the Neuse River estuary. Measurements taken at 15-minute intervals included near-surface and near-bottom specific conductance; near-surface water temperature; and near-surface, mid-depth, and near-bottom dissolved-oxygen concentrations. In the Pamlico River estuary, salinities generally ranged from less than 0.1 to 20 parts per thousand during the period October 1991 through September 1992. Recorded water temperatures in the Pamlico River were between 3.5 and 33 degrees Celsius during the measurement period. Dissolved-oxygen concentrations ranged from less than 1 to 23 milligrams per liter. In the Neuse River estuary, salinities ranged from 0.3 to 27 parts per thousand between October 1991 and September 1992. During the same period, recorded water temperatures in this estuary were between 4 and 34 degrees Celsius. Dissolved-oxygen concentrations ranged from less than 1 to greater than 22 milligrams per liter. Daily mean values of salinity; water temperature; dissolved-oxygen concentrations; and dissolved oxygen, percent saturation, are presented in tables and graphs. Five-day mean values of water temperature and dissolved-oxygen concentrations for day and night conditions also are presented in tables. Data are presented illustrating the vertical distribution of selected constituents at each site for selected dates.

  11. 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

  12. Estimation of ecologically significant circulation features of the Columbia River estuary and plume using a reduced-dimension Kalman filter

    NASA Astrophysics Data System (ADS)

    Frolov, Sergey; Baptista, António M.; Zhang, Yinglong; Seaton, Charles

    2009-02-01

    A data assimilation method was used to estimate the variability of three ecologically significant features of the Columbia River estuary and plume: the size of the plume, the orientation of the plume, and the length of the salinity intrusion in the estuary. Our data assimilation method was based on a reduced-dimension Kalman filter that enables fast data assimilation of nonlinear dynamics in the estuary and plume. The assimilated data included measurements of salinity, temperature, and water levels at 13 stations in the estuary and at five moorings in the plume. Our experimental results showed that data assimilation played a significant role in controlling the magnitude and timing of dynamic events in the Columbia River estuary and plume, such as events of extreme salinity intrusion and events of regime transitions in the plume. Data assimilation also changed the response of the salinity intrusion length to variations in the Columbia River discharge, hence imposing a new dynamic on the simulated estuary. The validation of the assimilated solution with independent data showed that these corrections were likely realistic, because the assimilated model was closer to the true ocean than the original, non-assimilated model.

  13. Rapid, Human-Induced Siltation of the Macro-Tidal Ord River Estuary, Western Australia

    NASA Astrophysics Data System (ADS)

    Wolanski, E.; Moore, K.; Spagnol, S.; D'Adamo, N.; Pattiaratchi, C.

    2001-11-01

    Field studies on the sediment dynamics of the two arms of Cambridge Gulf, tropical Western Australia, were undertaken. The system is macro-tidal with 8 m tides. The West Arm is the estuary of the Durack and Pentecost rivers, which are largely untouched by human activities. The East Arm is the estuary of the Ord River affected by land clearing which started 100 years ago, and by two river dams constructed 30 years ago. Prior to damming of the Ord River, the natural flow in all rivers was highly seasonal, characterized by small, at times negligible, flow during the dry season, which lasts eight months, and occasional river floods during the wet season, which lasts four months. The river flow has been regulated in the East Arm as a result of damming; this resulted in suppressing large river floods. The salinity intrusion length has decreased by about 50% in the East Arm following river damming. The East Arm has silted measurably over the last 30 years, with the stream cross-sectional area decreasing by about 50%. Field and numerical studies suggest that this is due to the dam-induced suppression of large river floods, which has in turn allowed a greater amount of tidal pumping of sediment into the East Arm from Cambridge Gulf. Since tidal pumping is increasing as the system is silting, the East Arm appears to now be geomorphologically unstable as a result of human activities. Numerical studies suggest it may take as little as 100 years for the Ord River to reach a new equilibrium. Modelling suggests that this equilibrium may be characterized by a salinity intrusion length half that before damming, a channel width and depth reduced by 70%, and a much stronger tidal asymmetry characterized by an increasing size of the tidal bore. The West Arm appears to be at equilibrium since there has been no net loss or gain of sediment for the last 111 years. Tidal dynamics and river floods appear responsible for self-scouring this channel.

  14. Importance of budgets for estimating the input of groundwater-derived nutrients to an eutrophic tidal river and estuary

    NASA Astrophysics Data System (ADS)

    Makings, Uriah; Santos, Isaac R.; Maher, Damien T.; Golsby-Smith, Lindsay; Eyre, Bradley D.

    2014-04-01

    Groundwater is often overlooked as a source of nutrients to estuaries and most previous groundwater-surface water exchange studies did not consider the input of dissolved organic nutrients. Here, we hypothesize that groundwater is contributing to high dissolved inorganic and organic nutrient concentrations in an eutrophic subtropical tidal river and estuary (Caboolture River, Queensland, Australia). Several spatial radon (222Rn, a natural groundwater tracer) surveys indicated that the majority of groundwater discharge occurred in the tidal river just upstream of the estuary, and that the radon hotspot did not necessarily coincide with the nutrient hotspot. A radon mass balance revealed that groundwater discharge into the tidal river was equivalent to about 50% of the gauged river flow in February 2012. Groundwater discharge apparently contributed 85% of ammonium and 35% of phosphate entering the estuary. In spite of significant correlations between radon and nitrate and dissolved organic nitrogen (DON) during spatial surveys, groundwater could account for only 7% of nitrate and 9% of DON inputs due to low groundwater concentrations and other sources (i.e., apparently a sewage treatment plant for nitrate and floodplain tributaries for DON). Because total dissolved nitrogen (TDN) was dominated by DON (69%) and nitrate (23%), the groundwater ammonium inputs were a minor source to the TDN pool within the tidal river and estuary. This study demonstrated that correlations between a groundwater tracer and nutrient concentrations do not necessarily illustrate causation. To assess how groundwater drives nutrient dynamics in estuaries, it may be important to include the tidal river (not only the estuarine salinity gradient) in field investigations, consider DON (not only ammonium and nitrate), and perform detailed budgets that include minor tributaries.

  15. Qualitative and numerical analyses of the effects of river inflow variations on mixing diagrams in estuaries

    USGS Publications Warehouse

    Cifuentes, L.A.; Schemel, L.E.; Sharp, J.H.

    1990-01-01

    The effects of river inflow variations on alkalinity/salinity distributions in San Francisco Bay and nitrate/salinity distributions in Delaware Bay are described. One-dimensional, advective-dispersion equations for salinity and the dissolved constituents are solved numerically and are used to simulate mixing in the estuaries. These simulations account for time-varying river inflow, variations in estuarine cross-sectional area, and longitudinally varying dispersion coefficients. The model simulates field observations better than models that use constant hydrodynamic coefficients and uniform estuarine geometry. Furthermore, field observations and model simulations are consistent with theoretical 'predictions' that the curvature of propery-salinity distributions depends on the relation between the estuarine residence time and the period of river concentration variation. ?? 1990.

  16. 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.

  17. 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

  18. 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

  19. Salt Marsh Formation in the Lower Hudson River Estuary

    NASA Astrophysics Data System (ADS)

    Merley, M. M.; Peteet, D. M.; Peteet, D. M.

    2001-05-01

    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 41 00; 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 (8m) includes freshwater seeds such as Viola, Potomageton and Alnus along with Salix buds. Basal material from Croton Point (10m) includes fibrous woody material, foraminifera and Zanichellia seeds and other brackish vegetational components. The basal material from Piermont (13.77m) is lacking any identifyable macrofossils between 150 and 500 microns. The basal material from Iona Island (10m) 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

  20. 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

  1. Impact of record flooding of a subtropical river on estuary/ocean exchange

    NASA Astrophysics Data System (ADS)

    Valle-Levinson, Arnoldo

    2012-01-01

    Measurements of current velocity profiles during and after cresting of the Suwannee River in Northern Florida, USA, were used to investigate the effects of increased river discharge on subtidal flows near the estuarine transition with the Gulf of Mexico. Three moored velocity profilers were deployed across a lower estuary cross-section. The cross-section bathymetry consisted of a channel (˜5.5 m deep) near the western bank of the estuary that shoaled monotonically eastward. Two-layer gravitational exchange developed only in the deepest part of the cross-section during the river cresting and persisted for ˜20 days. After this ˜20-day period, the net flow decreased and was seaward throughout the water column. Net flows outside the channel were seaward throughout the observation period and were modulated by the river pulse. By comparing the estuarine response in the 5.5-m channel to theoretical responses driven by a dynamic balance between pressure gradient and stress divergence, a condition required for two-layered flow was proposed. Gravitational exchange flow should be expected when the ratio of density-driven flow to river-induced flow is greater than 0.23 to 0.28. Smaller values of this ratio should produce unidirectional, seaward flows after a river pulse. Two-layered flows restricted to the channel can be explained also with this ratio because of the sensitivity of density-driven flows to local depth and eddy viscosity. These findings need to be tested against observations in other systems affected by extreme freshwater pulses.

  2. 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

  3. 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

  4. Dynamic genetic features of eukaryotic plankton diversity in the Nakdong River estuary of Korea

    NASA Astrophysics Data System (ADS)

    Lee, Jee Eun; Chung, Ik Kyo; Lee, Sang-Rae

    2016-08-01

    Estuaries are environments where freshwater and seawater mix and they display various salinity profiles. The construction of river barrages and dams has rapidly changed these environments and has had a wide range of impacts on plankton communities. To understand the dynamics of such communities, researchers need accurate and rapid techniques for detecting plankton species. We evaluated the diversity of eukaryotic plankton over a salinity gradient by applying a metagenomics tool at the Nakdong River estuary in Korea. Environmental samples were collected on three dates during summer and autumn of 2011 at the Eulsukdo Bridge at the mouth of that river. Amplifying the 18S rDNA allowed us to analyze 456 clones and 122 phylotypes. Metagenomic sequences revealed various taxonomic groups and cryptic genetic variations at the intra- and inter-specific levels. By analyzing the same station at each sampling date, we observed that the phylotypes presented a salinity-related pattern of diversity in assemblages. The variety of species within freshwater samples reflected the rapid environmental changes caused by freshwater inputs. Dinophyceae phylotypes accounted for the highest proportion of overall diversity in the seawater samples. Euryhaline diatoms and dinoflagellates were observed in the freshwater, brackish and seawater samples. The biological data for species composition demonstrate the transitional state between freshwater and seawater. Therefore, this metagenomics information can serve as a biological indicator for tracking changes in aquatic environments.

  5. 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.

  6. 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.

  7. 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.

  8. 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)

  9. 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.

  10. 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.

  11. [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

  12. 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

  13. 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.

  14. 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.

  15. Field monitoring of toxic organic pollution in the sediments of Pearl River estuary and its tributaries.

    PubMed

    Fu, J; Wang, Z; Mai, B; Kang, Y

    2001-01-01

    Field monitoring of the toxic organic compounds (PCBs, PAHs, organochlorine pesticides) in the top sediments of Pearl River Estuary and its up-streams were made. It was found that the highest concentrations of these toxic organic compounds occurred in the sediment sampled at Macau inner harbor (ZB013), which is a sink of suspended fine particles transported from the upstream waterways. Because of the affinity of the hydrophobic organic compounds (PAHs, PCBs) for the solid phase, these fine particle depositions led to accumulation of these compounds in the sediment of Macau. The atmospheric dry deposition may be another source of the toxic organic pollution in the sediment.

  16. Lanzavecchia mangrovi sp. n. (Nematoda, Dorylaimida) from mangroves of Red River Estuary, Vietnam.

    PubMed

    Gagarin, Vladimir G

    2014-02-12

    A new nematode species found in the Red River Estuary of Vietnam is described. Lanzavecchia mangrovi sp. n. is morphologically close to L. coomansi Nicholas, Stewart, 1984, but differs in its longer body (L = 2.71-3.76 µm versus L = 2.2-2.9 µm), shorter spicules (63-65 mm versus 72-88), longer prerectum (500-675 mm versus 262-310 µm) and shorter distal portion of tail in relation to the proximal portion (0.6-0.8 versus 0.9-2.3).

  17. 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

  18. 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)

  19. 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

  20. The hydrology of the upper Swan River Estuary with focus on an artificial destratification trial

    NASA Astrophysics Data System (ADS)

    Hamilton, David P.; Chan, Terence; Robb, Malcolm S.; Pattiaratchi, Chari B.; Herzfeld, Michael

    2001-09-01

    observed further than 350 m away. The upper Swan River estuary, although relatively narrow and strongly vertically stratified, is unsuited to destratification using bubble plumes. Cycling of spring and neap tides and non-tidal water level changes, together with freshwater inflows to the estuary, strongly limit the longitudinal extent of mixing by bubble curtains.

  1. 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

  2. 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

  3. Simulation of hydrodynamics and solute transport in the Pamlico River estuary, North Carolina

    USGS Publications Warehouse

    Bales, Jerad; Robbins, Jeanne C.

    1995-01-01

    An investigation was conducted to characterize flow, circulation, and solute transport in the Pamlico River estuary, North Carolina. The study included a detailed field-measurement program and the calibration, validation, and application of a physically realistic numerical model of hydro- dynamics and transport. Water level, salinity, water temperature, wind speed and direction, and current data were collected during March 1988 through September 1992, and were used to characterize physical conditions in the estuary. Data from pre- existing streamflow gaging stations and meteoro- logical stations were also used. A two-dimensional vertically averaged hydrodynamic and solute transport model was applied to the 48-kilometer study reach. The model domain was discretized into 5,620 separate 200- by 200-meter computational cells. Model calibration was achieved through adjustment of parameters for June 14-30, 1991. Data from selected periods in 1989 and 1991 were used for model validation. Water levels used for model calibration and validation ranged from -0.052 to 0.698 meter; salinities ranged from 0.1 to 13.1 parts per thousand; and wind speeds ranged from calm to 22 meters per second. The model was tested for stratified and unstratified conditions. Simulated and observed data were used to evaluate model performance. The calibrated model was applied for selected periods in 1989 and 1991. Instantaneous flows were simulated at each boundary and at mid- estuary. Circulation patterns were characterized using vector plots, particle tracking, and solute transport. Particle tracks showed that materials released at mid-estuary may remain in the system for 25 days or longer.

  4. 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.

  5. [Spatial distribution and ecological risk assessment of heavy metals in the estuaries surface sediments from the Haihe River Basin].

    PubMed

    Lü, Shu-Cong; Zhang, Hong; Shan, Bao-Qing; Li, Li-Qing

    2013-11-01

    It is well known that the rivers in the Haihe River Basin have been seriously polluted. However, what is the present condition of the estuary pollution and how the polluted inland rivers affect the estuary areas are not clear. 10 main estuaries of the Haihe River Basin were selected to measure the contents of typical heavy metals (Pb, Cu, Zn, Cd, Cr and Ni) in the surface sediments and to analyze the spatial distribution of these heavy metals. The potential ecological risk index was used to assess the ecological risk of the six heavy metals in the estuaries. The results showed that the contents of Pb, Cu, Zn, Cd, Cr and Ni in the surface sediments of the 10 estuaries were all higher than their background values in the main local soil types and the contents of Cu, Ni and Pb were 2.3-2.6 times as high as their background values, which indicated that the estuaries were contaminated by the six heavy metals. The results also indicated that the contents of the six heavy metals in surface sediment varied from one estuary to another. The four heavy metals of Cr, Cu, Ni and Zn had bigger spatial differences than Pb and Cd in the contents in sediment from different estuaries. The contents of Cr, Cu, Ni and Zn in sediment were higher in the estuaries of the Yongdingxin River, Ziyaxin River and Beipai River than those in the other estuaries, and there were significant correlations between each other (R(Cu-Zn) = 0.891, R(Cu-Cr) = 0.927, R(Cu-Ni) = 0.964, R(Zn-Cr) = 0.842, R(Zn-Ni) = 0.939, and R(Cr-Ni) = 0.879, P < 0.01), which indicated that they possibly came from the same sources. Moreover, the contents of Cr, Cu, Ni and Zn in sediment also had significant correlations with the populations of sub-river basins with correlation coefficients of 0.855, 0.806, 0.867 and 0.855 (P < 0.01), respectively. The contents of Cd and Pb had smaller spatial differences in sediment from different estuaries than the other heavy metals, with the values ranged 23.3-95.8 mg x kg(-1) and 0

  6. Historical deposition behaviors of PAHs in the Yangtze River Estuary: role of the sources and water currents.

    PubMed

    Wang, Dongxin; Feng, Chenghong; Huang, Luxia; Niu, Junfeng; Shen, Zhenyao

    2013-02-01

    Historical profiles and sources of PAHs at two typical sediment cores (i.e., the shipping route site and the shoal site) were fully compared to probe the controlling factors, specifically the water currents, for the PAHs deposition processes in the Yangtze River Estuary. Compared with ocean water currents, river runoff affected by the water impoundment of the Three Gorges Dam greatly affected the PAHs levels and percent contribution of PAHs sources in the two cores. River runoff hindered the PAHs deposition in shoal site, while a contrary phenomenon was observed for the shipping route site. Though the PAHs in the estuary were mainly from river catchment, only low ring PAHs in the shipping route site were mainly from the upper reach of the river. Coarse sediments with higher organic carbon content also accounted for the higher deposition levels of PAHs in the shipping route site. PMID:23200571

  7. 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.

  8. 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 the

  9. 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

  10. 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

  11. 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

  12. Antibiotics in riverine runoff of the Pearl River Delta and Pearl River Estuary, China: concentrations, mass loading and ecological risks.

    PubMed

    Xu, Weihai; Yan, Wen; Li, Xiangdong; Zou, Yongde; Chen, Xiaoxiang; Huang, Weixia; Miao, Li; Zhang, Ruijie; Zhang, Gan; Zou, Shichun

    2013-11-01

    Ten antibiotics belonging to three groups (macrolides, fluoroquinolones and sulfonamides) were investigated in riverine runoff of the Pearl River Delta (PRD) and Pearl River Estuary (PRE), South China for assessing the importance of riverine runoff in the transportation of contaminants from terrestrial sources to the open ocean. All antibiotics were detected in the eight outlets with concentrations ranging from 0.7 to 127 ng L(-1). The annual mass loadings of antibiotics from the PRD to the PRE and coast were 193 tons with 102 tons from the fluoroquinolone group. It showed that antibiotics decreased from the riverine outlets to the PRE and open ocean. Risk assessment showed that most of these antibiotics showed various ecological risks to the relevant aquatic organisms, in which ofloxacin (OFL), erythromycin (ETM) and ciprofloxacin (CIP) posed high ecological risks to the studied aquatic environments.

  13. Circulation, density distribution and neap-spring transitions in the Columbia River Estuary

    NASA Astrophysics Data System (ADS)

    Jay, David A.; Dungan Smith, J.

    This paper has two purposes. The first is to use tidal-monthly variations in the density and velocity fields and the salt and water transports as key to understanding the circulation of the Columbia River Estuary and other river estuaries. The Columbia River Estuary is a good natural laboratory in this regard, because the flushing time of the system (a few days) is short relative to the tidal month during all seasons. This allows the occurrence of distinct transitions from a strongly to a weakly stratified water column (and back) during the tidal month. Furthermore, because atmospheric processes are secondary to riverflow and tidal influence in determining the circulation, most of the energy in circulatory phenomena is confined to distinct tidal, tidal-monthly and seasonal frequency bands. Observations of salt transport and neap-spring transitions reported herein should provide important constraints on future theoretical studies of estuarine circulation. The second purpose is to describe the circulation and density field of the Columbia River Estuary as background for understanding the geologic and biological investigations discussed in other papers in this volume. Previous investigations have focused on seasonal variations in riverflow as governing the turbidity maximum and biological productivity. Studies reported in this volume show that tidal monthly variations in circulatory processes are of comparable importance. With regard to the velocity field, the influence of stratification causes the tidal flow to show the largest vertical variations in phase and amplitude in the lower estuary. The vertical distribution of the mean current is controlled by the ebb-flood asymmetry in the time-dependent flow, vertical mixing processes, the baroclinic pressure gradient, and interaction of the flow with topography. Net upstream bottom flow is weak or absent during periods of weak stratification; it is substantially only when the system is highly stratified. Net upstream

  14. Distribution and sources of the polycyclic aromatic hydrocarbons in the sediments of the Pearl River estuary, China.

    PubMed

    Zhang, Jian-Dong; Wang, You-Shao; Cheng, Hao; Jiang, Zhao-Yu; Sun, Cui-Ci; Wu, Mei-Lin

    2015-10-01

    The Pearl River delta, one of the most prosperous economically region in China, has experienced significant contaminant inputs. However, the dynamics of pollutants in the Pearl River estuary and the adjacent coastal areas are still unclear at present. In the paper, distribution and sources of polycyclic aromatic hydrocarbons (PAHs) were investigated in the surface sediments of the Pearl River estuary. The total PAHs concentrations ranged from 126.08 to 3828.58 ng/g with a mean value of 563.52 ng/g, whereas the highest PAHs were observed in Guangzhou channel. Among the U.S. Environmental Protection Agency's 16 priority PAHs, PAHs with 3-4 rings exhibited relative higher levels. A positive relationship was found between PAHs and total organic carbon. The source analysis further showed that the major sources of PAHs in the Pearl River estuary were originated from the pyrolytic inputs, reflecting a mixed energy structure such as wood, coal and petroleum combustion. In summary, although PAHs in Lingding Bay and the adjacent coastal areas of the Pearl River estuary exhibited a relatively low pollution level, the relatively high pollution level of PAHs in Guangzhou channel will be attended.

  15. Distribution of Uranium Isotopes in the Kaoping River Estuary, Southwestern Taiwan

    NASA Astrophysics Data System (ADS)

    Wang, R.; You, C.

    2011-12-01

    To gain a better understanding of the geochemical behavior of uranium (U) isotopes in estuarine mixing processes, we collected river waters along the Kaoping river estuary both during dry and wet seasons, and analyzed these for major and trace elements and Sr and U isotopes. Dissolved major elements (i.e. Na, Mg, Ca, and Cl) and Sr behave conservatively along with salinity in the estuary. Their vertical profiles reveal mixing between an upper layer of fresh water and a lower layer of intruded seawater. The Sr isotopes support a similar mixing scenario between a more radiogenic, continentally-derived fresh water and less radiogenic seawater. Dissolved B, Ba and U, however, indicate more complicated distribution patterns possibly related to groundwater input, benthic or diffusion flux and water/solid interactions. Riverine U signal normally has higher 234U/238U activity ratio due to the α-recoil and weathering effects than the constant value of open ocean seawater and, thus, potentially can be used as a tracer of terrigenous water inputs. The U isotopic ratios show negative correlation with U content in vertical profiles, with unusually low U concentrations occurring at 1 to 2 m depth where U isotopes are more radiogenic. However, the U isotopic ratios in the upper stations deviate from the mixing line between the fresh water and seawater, possibly due to the effect of groundwater seepage or coastal groundwater discharge. Data also seem to indicate that the wet season samples show high trace element concentrations due to inputs from top soils or atmospheric dusts. This study reveals that U isotopes are potential tracers for studying land/sea interactions and sensitive monitors of environmental changes in estuaries.

  16. 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.

  17. 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.

  18. 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.

  19. Dissolved insecticides and polychlorinated biphenyls in the Pearl River Estuary and South China Sea.

    PubMed

    Zhang, Z; Dai, M; Hong, H; Zhou, J L; Yu, G

    2002-12-01

    Persistent organic pollutants (POPs) such as organochlorine (OCl) insecticides and polychlorinated biphenyls (PCB), together with the new generation of organophosphorus (OP) insecticides, are of global concern, due to their widespread occurrence, persistence, bioaccumulation and hormone disruption potential. This paper represents an attempt to study the source and transportation of such pollutants in estuarine and coastal environments as an integrated ecosystem, by determining the levels of 18 OCl insecticides, 21 PCB congeners, and 17 OP insecticides in the Pearl River Estuary and South China Sea. The total concentrations varied from 126-1198 ng l(-1) for OCl insecticides, 33.38-1064 ng l(-1) for PCB congeners, and 4.44-6356 ng l(-1) for OP insecticides in the Pearl River Estuary. In comparison, their levels in the South China Sea were significantly lower, varying from 57.09-202 ng l(-1) for OCl insecticides, 21.72-144 ng l(-1) for PCBs, and 1.27-122 ng l(-1) for OP insecticides, respectively. The predominance of beta-HCH in HCHs, and DDE in DDTs in all water samples was clearly observed, suggesting beta-HCH and DDE's resistance to further degradation. The PCBs were dominated by those with 3-6 chlorines. The distribution characteristic of OP insecticides shows that five compounds (methamidophos, dimethoate, malathion, dichlorvos and omethoate) accounted for 56% and 72% of the total OP insecticide concentration. The relationship between pollutant concentrations and salinity in the estuary showed that they were all removed during the mixing process, therefore behaving non-conservatively.

  20. 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.

  1. Nutrient transport from mangrove river to seagrass bed in the Fukido estuary, Japan

    NASA Astrophysics Data System (ADS)

    terada, K.; Kutsumi, M.; Kanno, A.

    2012-12-01

    Many subtropical estuaries have the interlinked ecosystem of mangroves, seagrass beds and coral reefs and have kept the delicate balance in nature. This study investigated the spatial and temporal variation of nutrients (NH4-N, NO3-N, PO4-P and SS) and water currents in discussing the material transport between mangrove river mouth to seagrass beds. TN and NH4-N in the mangrove river mouth were 2~5 times higher than in seagrass bed. PO4-P increased in seagrass beds at the low tide. Water current exhibited the strong seaward flow in the ebb tide and circulating flow in the northeast of the bay. These movements could have affected the material exchanges between the mangrove and adjacent seagrass beds.

  2. Ecosystem health assessment in the pearl river estuary of China by considering ecosystem coordination.

    PubMed

    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.

  3. The axial salinity distribution in the delaware estuary and its weak response to river discharge

    NASA Astrophysics Data System (ADS)

    Garvine, Richard W.; McCarthy, Robert K.; Wong, Kuo-Chuin

    1992-08-01

    We use long term salinity and river discharge data from the Delaware estuary, U.S.A. to determine the mean axial salinity distribution and the salinity response to fresh water discharge. The Delaware is a weakly stratified estuary with a typical vertical salinity variation of only 1 psu. We find that over most of the estuarine salt intrusion length the mean axial distribution of salinity is surprisingly close to a linear decrease with axial distance. Using linear regression analysis, we find that the response of salinity to river discharge is surprisingly weak. The equivalent displacement of a given isohaline for a change in discharge of one standard deviation is only about 4 km, about half the amplitude of the M2 tidal displacement. This implies that some powerful buffering agent exists to reduce the salinity response. We suggest two possible mechanisms for this agent: the action of vertical shear flow dispersion in a tidally stirred regime and the action of lateral shear coupled to strong lateral salinity gradients.

  4. 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

  5. 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.

  6. Ecosystem health assessment in the pearl river estuary of China by considering ecosystem coordination.

    PubMed

    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

  7. [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

  8. 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.

  9. 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

  10. Sediment accumulation in the Siletz River estuary in response to changes in hydroclimate and land use.

    NASA Astrophysics Data System (ADS)

    Pakenham, A.; Wheatcroft, R.

    2008-12-01

    The transfer of sediment from source to sink involves a complex set of processes that vary over multiple time and space scales. In the Pacific Northwest, there is anecdotal evidence that many estuaries are filling rapidly with sediment due to changes in hydroclimatology coupled with land-use changes. Because both factors may co-exist, the relative contribution of each, the mechanisms of sediment delivery (event vs. steady), and the role of larger scale processes, such as sea level rise, are important issues to disentangle. To address these issues we are studying the Siletz River, a small (<1000 km2), mountainous river system in the Oregon Coast Range. Precipitation and stream flow patterns in this region are forced by the PDO-ENSO, with a cool, wet period from 1945 to 1975. In addition, the Siletz watershed was extensively logged following WWII, thereby exacerbating sediment erosion from the watershed. A variety of evidence (e.g., x-radiographs, grain size, C-14, Pb-210 and Cs-137 geochronology) collected within the estuary indicates, however, that there has not been a clear acceleration of sediment accumulation during the latter half of the 20-th century, and suggests extrabasinal effects (e.g., sea level rise, neotectonics) may control accumulation.

  11. 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).

  12. Two-dimensional circulation modeling of the Pamlico River estuary, North Carolina

    USGS Publications Warehouse

    Giese, G.L.; Bales, Jerad

    1992-01-01

    A two dimensional, vertically averaged, unsteady flow model was applied to a 50- kilometer reach of the Pamlico River estuary, North Carolina. The model computational grid, which consists of about 16,000 square cells, each 200 meters on a side, was developed from more than one million depth soundings. Information from a comprehensive data-collection network, including six water-level stations, six temperature and salinity measurement stations, and one wind measurement station, was used to provide data for boundary conditions and for model calibration. Preliminary model results for this ongoing study were sensitive to the presence of a lateral water-level gradient at the downstream boundary. For the simulation period, water-level oscillations at the downstream boundary were much more important in controlling Pamlico River flows than were local winds blowing over the surface of the estuary. Average absolute differences between observed and simulated water levels at two measurement sites were less than 2 centimeters for the 8-day calibration period.

  13. [Ecological characteristics of phytoplankton in coastal area of Pearl River estuary].

    PubMed

    Dai, Ming; Li, Chunhou; Jia, Xiaoping; Zhang, Hanhua; Chen, Ruiwen

    2004-08-01

    Five cruises of phytoplankton survey were made in costal area of Pearl River estuary in 1998-1999. The results showed that 239 species were identified, 72.4% of which belonging to Bacillariophyta, 23.8% to Pyrrophyta, and 3.8% to others. The dominant species were warm and eurythermic species Thalassiothrix frauenfeldii, Nitzschia delicatissima, Thalassiothrix frauenfeldii and Thalassiosira subtilis, and changed with an obvious seasonal succession. The cell density ranged from 0.2 x 10(4) to 2,767.1 x 10(4) cell x m(-3), with an average of 98.7 x 10(4) cell x m(-3), and the mean cell density was obviously higher in summer and winter than in spring and autumn. The regional variation revealed that the cell density in shore area was visibly higher than that in offshore area, and the largest density area was at the southeast of Shangchuan Island all the year around. The range of mean Shannon-Wiener index, Pielou evenness index and biodiversity threshold was 2.63-3.17, 0.53-0.71 and 1.74-2.23, respectively. According to the diversity index, it was concluded that the diversity level of phytoplankton community in coastal area of Pearl River estuary was relatively high and stable.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Radium isotopes assess water mixing processes and its application in the Zhujiang River estuary

    NASA Astrophysics Data System (ADS)

    Guo, Xiaoyi; Xu, Bochao; Yu, Zhigang; Li, Xiuqin; Nan, Haiming; Jian, Huimin; Jiang, Xueyan; Diao, Shaobo; Gao, Maosheng

    2016-10-01

    Radium (Ra) isotopes are useful for tracing water mass transport and examining estuarine hydrological dynamics. In this study, several hydrological parameters, nutrients, chlorophyll-a (chl-a), suspended particulate matter (SPM) and Ra isotopes (223Ra, 224Ra and 226Ra) of surface waters of the Zhujiang (Pearl) River estuary (ZRE) were measured. This was done for both winter (December) and summer (July) seasons, to quantitatively understand the seasonal characteristics of river plume flow rate and trajectories, as well as the ecological response. The results show that Ra concentrations in summer were higher than in winter, especially 224Ra (about 2-5 times higher). The spatial distribution of three Ra isotopes and relative Ra water ages indicated that river water mainly flushed out of ZRE through the western side in winter, where the water transport was about 5 days faster than in the eastern zone. In summer, diluted river water expended to the east side, resulting in fairly similar water ages for both sides of the river mouth. Although nutrients were higher during the summer season, lower chl-a concentrations indicated that reduced primary production might be caused by high SPM (low light penetration). The results obtained from this study will provide knowledge needed for effectively developing and managing the ZRE.

  19. 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.

  20. 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

  1. 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

  2. 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

  3. 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.

  4. Relocation of the Yellow River estuary in 1855 AD recorded in the sediment core from the northern Yellow Sea

    NASA Astrophysics Data System (ADS)

    Zhou, Xin; Jia, Nan; Cheng, Wenhan; Wang, Yuhong; Sun, Liguang

    2013-12-01

    Relocation of the Yellow River estuary has significant impacts on not only terrestrial environment and human activities, but also sedimentary and ecological environments in coastal seas. The responses of regional geochemical characteristics to the relocation event, however, have not been well studied. In the present study, we performed detailed geochemical elemental analyses of a sediment core from the northern Yellow Sea and studied their geochemical responses to the 1855 AD relocation of the Yellow River estuary. The results show that TOC/TN, Co/Al2O3, Cr/Al2O3, Ni/Al2O3 and Se/Al2O3 ratios all decreased abruptly after 1855 AD, and similar decreases are observed in the sediments of the mud area southwest off the Cheju Island. These abrupt changes are very likely caused by the changes in source materials due to the relocation of the Yellow River estuary from the southern Yellow Sea to the Bohai Sea, which the corresponding decreasing trends caused by the changes in main source materials from those transported by the Liaohe River, the Haihe River and the Luanhe River to those by the Yellow River. Because the events have precise ages recorded in historical archives, these obvious changes in elemental geochemistry of sediments can be used to calibrate age models of related coastal sea sediments.

  5. Effects of Human Activities on Submarine Topography in Lingding Bay of the Pearl River Estuary During the Last Decade

    NASA Astrophysics Data System (ADS)

    WU, Z. Y.; Saito, Y.; Milliman, J. D.; Zhao, D.; Zhou, J.

    2015-12-01

    Estuaries have been the site of intensive human activities. During the past century, decreased fluvial water and sediment discharge, increasing land reclamation, changing climate, and rising sea level have had an ever-increasing impact on river deltas, particularly those deltas bordering Southeast Asia. Using six stages of navigational and bathymetric chart data from 1906 to 2013 and 2 years (2012,2013) single-beam bathymetric data, together with more than 50 years of fluvial discharge data, we document the impact of human activities on the Pearl River Delta and its estuary at Lingding Bay. Between 1906 and 2010, land reclamation decreased the bay's water area by ~300 km2 (>17%), mostly at the expense of the shrinking intertidal and shallow subtidal mudflats. Before 1980, the estuary was mainly governed by natural processes with slight net deposition, whereas after 1980 dredging in the estuary and large port engineering projects changed the estuarine topography by shallowing the shoals and deepening the troughs. From 1955 to 2010, the water volume of Lingding Bay decreased by 536 × 106 m3 for a net decrease of 9.7 × 106 m3 a year, which indicates that approximately 9.7 Mt/yr of sediment was deposited in Lingding Bay during that period. In 2012 and 2013, large-scale human activities within Lingding Bay included continued dredging plus a surge of sand excavation that changed local water depths by ±5 m/yr, far exceeding the range of natural topographic evolution in the estuary. The impacts of various human activities have significantly changed submarine topography in Lingding Bay of the complex Pearl River Estuary. With continuing economic expansion in the Pearl River Delta, Lingding Bay should continue to shrink in both area and water volume.

  6. 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

  7. [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

  8. 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...

  9. 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...

  10. 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...

  11. 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...

  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.

  13. 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...

  14. Distribution of heavy metals in sediments of the Pearl River Estuary, southern China: implications for sources and historical changes.

    PubMed

    Ye, Feng; Huang, Xiaoping; Zhang, Dawen; Tian, Lei; Zeng, Yanyi

    2012-01-01

    The distribution of heavy metals (Pb, Zn, Cd and As) in sediments of the Pearl River Estuary was investigated. The spatial distribution of heavy metals displayed a decreasing pattern from the turbidity maxima to both upstream and downstream of the estuary, which suggested that suspended sediments played an important role in the trace metal distribution in the Pearl River Estuary. In addition, metal concentrations were higher in the west part of the estuary which received most of the pollutants from the Pearl River. In the sediment cores, fluxes of heavy metals were consistent with a predominant anthropogenic input in the period 1970-1990. From the mid-1990s to the 2000s, there was a significant decline in heavy metal pollution. The observed decline has shown the result of pollution control in the Pearl River Delta. However, it is noteworthy that the metal concentrations in the most recent sediment still remained considerably high. Taken together, the enrichment of heavy metals in sediments was largely controlled by anthropogenic pollution.

  15. Physical, chemical, and biological aspects of the Duwamish River Estuary, King County, Washington, 1963-67

    USGS Publications Warehouse

    Santos, John F.; Stoner, J.D.

    1972-01-01

    This report describes the significant results to 1967 of a comprehensive study that began in 1963 to evaluate what changes take place in an estuary as the loads .of raw and partially treated industrial and municipal wastes are replaced by effluent from a secondary treatment plant. The study area is the Duwamish River estuary, about 18.3 river kilometers long. At mean sea level the estuary has a water-surface area of about 1 square mile and a mean width of 440 feet. At the lowest and highest recorded tides, the volume of the estuary is about 205 and 592 million cubic feet, respectively. The estuary is well stratified (salt-wedge type) at fresh-water inflows greater than 1,000 cfs (cubic feet per second), but when inflow rates are less than 1,000 cfs the lower 5.6 kilometers of the estuary grades into the partly mixed type. The crosschannel salinity distribution is uniform for a given location and depth. Salinity migration is controlled by tides and fresh-water inflow. At fresh-water inflow rates greater than 1,000 cfs, water in the upper 8.4 kilometers of the estuary is always fresh regardless of tide. At inflow rates less than 600 cfs and tide heights greater than 10 feet; some salinity has been detected 16.1 kilometers above the mouth of the estuary. Studies using a fluorescent dye show that virtually no downward mixing into the salt wedge occurs; soluble pollutants introduced at the upper end of the estuary stay in the surface layer (5-15 ft thick). On the basis of dye studies when fresh-water inflow is less than 400 cfs, it is estimated that less than 10 percent of a pollutant will remain in the estuary a minimum of 7 days. Longitudinal dispersion coefficients for the surface layer have been determined to be on the order of 100-400 square feet per second. Four water-quality stations automatically monitor DO (dissolved oxygen), water temperature, pH, and specific conductance; at one station solar radiation also is measured. DO concentration in the surface layer

  16. The influence of late summer typhoons and high river discharge on water quality in Hong Kong waters

    NASA Astrophysics Data System (ADS)

    Zhou, Weihua; Yin, Kedong; Harrison, Paul J.; Lee, Joseph H. W.

    2012-10-01

    A typhoon produces a rapid mixing and flushing event and it can be added to the list of other factors such as shallow water depth, spring tidal mixing, the Pearl River discharge, summer upwelling that make Hong Kong waters relatively resistant to eutrophication impacts. Two typhoons passed over Hong Kong waters and provided an opportunity to document the changes in water quality in late summer 2003. Before the typhoon (Aug 19-20) and during a neap tide, a large algal bloom (>10 μg Chl-a L-1) occurred in the stratified southern waters influenced by the Pearl River estuarine waters with high NO3. However, PO4 and SiO4 were drawn down to near limiting concentrations by the large bloom. After the typhoons, Chl-a decreased to 2 μg L-1 due to vertical mixing and advection. The heavy rainfall and increased river discharge quickly re-set the water column to the usual strong summer stratification in only a few days. As a result, high nutrients in the river discharge stimulated another large algal bloom a few days after the next neap tide when tidal mixing was reduced. In the southern waters, the deeper station showed stronger stratification and lower bottom dissolved oxygen (DO) than the shallower station suggesting that the low DO in the bottom water may have come from offshore transport.

  17. Influence of river discharge patterns on the hydrodynamics and potential contaminant dispersion in the Douro estuary (Portugal).

    PubMed

    Azevedo, Isabel C; Bordalo, Adriano A; Duarte, Pedro M

    2010-05-01

    Freshwater input to estuaries is a fundamental feature of these ecosystems, which may be profoundly altered by river damming as human needs for water consumption, irrigation or energy production increase. The Douro estuary is limited upstream by a dam since 1985, which reduced its length by ca. 60%. Freshwater inputs to the estuary are now irregular and greatly dependent on hydroelectric power demand; values ranging from zero to over 1000m(3)s(-1), in a matter of hours, especially in summer are common. In the present study, a three-dimensional hydrodynamic model was applied to the Douro estuary. The model was calibrated and validated against water elevation, current velocity, salinity and temperature data. Thereafter, it was used to analyse the effects of different flow regimes and magnitudes on estuarine hydrodynamics and contaminant dispersion. Results obtained suggest that the highly variable flow regimes, currently observed in the Douro, tend to reduce water column stratification and to enhance seawater intrusion, when compared with flow discharges of similar average magnitude, but lower variability. Stable flows seem to be the most effective in dispersing contaminants eventually introduced into the estuary through its small river tributaries. Overall results suggest that flow management may have important effects on estuarine hydrodynamics through non-linear interactions between flow magnitude and variability.

  18. Spatial variation in organic matter utilization by benthic communities from Yura River-Estuary to offshore of Tango Sea, Japan

    NASA Astrophysics Data System (ADS)

    Antonio, Emily S.; Kasai, Akihide; Ueno, Masahiro; Won, Nam-il; Ishihi, Yuka; Yokoyama, Hisashi; Yamashita, Yoh

    2010-01-01

    We investigated the distribution of δ 13C and δ 15N of organic matter among benthic communities from the upper estuary of Yura River to offshore of Tango Sea, Japan, to determine spatial variation in utilization of organic matter by benthic communities. The δ 13C values of benthic animals ranged from -27 to -15‰ in the upper estuary, -21 to -15‰ in the lower estuary, -20 to -16‰ in the shallow coast (5-10 m depths), -18 to -16‰ in the deep coast (30-60 m depths) and -19 to -15‰ in offshore (100-150 m depths) stations. Adapting the dual isotope values to mixing models, we estimated the relative contributions of potential food sources to the benthos diet. Phytoplankton and macroalgae that intruded the estuary in summer were utilized as alternative food aside from the terrestrial-origin organic matter assimilated by the estuarine benthic consumers. Resuspended benthic microalgae were important source of energy in the shallow coastal stations, while abundant supply of phytodetritus fueled the deep coastal and offshore benthic food webs. Spatial difference in the diet of benthic communities depends largely on the shifts in the primary carbon source. Thus, benthic communities are important link of autochthonous/allochthonous production and secondary production in the continuous river-estuary-marine system.

  19. Geochemistry of the suspended sediment in the estuaries of the Mandovi and Zuari rivers, central west coast of India.

    PubMed

    Kessarkar, Pratima M; Shynu, R; Rao, V Purnachandra; Chong, Feng; Narvekar, Tanuja; Zhang, Jing

    2013-05-01

    The geochemistry of the suspended particulate matter (SPM) collected during the monsoon was determined to identify the sources of SPM and to understand the physicochemical processes in the Mandovi and Zuari river estuaries. The concentrations of SPM decrease seaward in both estuaries, but are relatively high at bay stations. Kaolinite is the most dominant clay mineral in the upstream of both rivers. Smectite increases seaward in both estuaries and is abundant in the bay. Upstream stations of Mandovi, where ore deposits are stored on the shore, exhibit high Fe, Mn, total rare earth elements (∑REE), and middle REE- and heavy REE-enriched patterns. Channel stations of both estuaries exhibit middle REE- and light REE-enriched patterns, which gradually changed seaward to middle REE- and heavy REE-enriched patterns. Canal stations exhibit the highest concentrations of major and trace metals. High metal/Al ratios occur at stations in the upstream of Zuari and at the confluence of canals in the Mandovi estuary. Enrichment factors of metals indicate that Mn is significantly polluted while other metals are moderately polluted. The δ(13)C and δ(15)N of organic matter indicate that the terrigenous organic matter at the upstream is diluted seaward by marine organic matter. Organic matter at bay stations is largely marine and altered-type. The compositions of SPM are controlled by the particulates from ore dust, the geology of the drainage basins, and the physicochemical processes in the estuaries. Particulates resuspended from the bay are dominated by ore dust, which are advected into the channels of both estuaries during the lull periods of the monsoon.

  20. Blowing in the wind: the impact of China's Pearl River Delta on Hong Kong's air quality.

    PubMed

    Xiao, Feng; Brajer, Victor; Mead, Robert W

    2006-08-15

    The local versus regional nature of Hong Kong's air pollution remains an unresolved issue with important policy implications. Specifically, the potential benefits of different air quality improvement efforts will vary dramatically, depending upon the nature of the pollution. This multi-disciplinary paper attempts to resolve the issue, using a time series, cross-sectional panel of pollution data from Hong Kong and southern China, along with weather variables from Hong Kong. An econometrically-based structural model of Hong Kong pollution levels is constructed, and Granger causality tests are conducted. Then, using results from the structural model, the health impacts on Hong Kong residents of reductions in mainland China's pollution are estimated and valued in economic terms. Results indicate that for the pollutants PM(10) and NO(2) causality runs in both directions, highlighting the regional nature of the air pollution problem. However, the potential health benefits resulting from reductions in southern China's pollution are relatively small. In US dollar terms, the averted mortality benefits of a large China-focused clean up are approximately $40 million, but the benefits of a more modest Hong Kong-focused effort are nearly $200 million. The resulting policy implication is that Hong Kong's primary pollution control efforts should lie at the local level.

  1. Recent sediments of the St. Marks River coast, northwest Florida, a low-energy, sediment-starved estuary

    SciTech Connect

    Highly, A.B. . Dept. of Geology Florida Geological Survey, Tallahassee, FL ); Donoghue, J.F. . Dept. of Geology); Garrett, C.; Hoenstine, R.W.; Hertler, H. )

    1994-03-01

    The St. Marks river of northwest Florida drains parts of the central panhandle of northwestern Florida, and a small area in southwestern Georgia. It traverses nearly 56.3 kilometers through a watershed of 1,711 square kilometers. The slow-moving river carries little sediment and terminates in Apalachee Bay, a low-energy embayment in the northeasternmost Gulf of Mexico. The coastal region is characterized by mudflats, seagrass beds, and an absence of sandy beaches and barrier islands. Clastic sediments of the coast and shelf rest on a shallow-dipping carbonate platform. The upper surface of the platform is locally karstic. As a result, like other rivers in this region of northwest Florida, the St. Marks watershed is marked by sinkholes and disappearing streams. The fact that the river travels underground through part of its lower watershed serves to trap or sieve some of its clastic load. In the estuary, the undulating karst topography causes the estuarine sediments to vary in thickness from 0 to 4+ meters. The concave shape of the coastline and its orientation with respect to prevailing winds result in low average wave energy. Sedimentation is therefore controlled by riverine and tidal forces. The relatively low energy conditions result in good preservation of the sedimentary record in the St. Marks estuary. A suite of sediment cores has been collected in the lower river, estuary and adjacent Gulf of Mexico. Lead-210 dating results indicate a slow average sedimentation rate ([approximately] 1mm/yr). Investigation of sedimentation rates and sediment characteristics over time in the St. Marks estuary indicate that sedimentologic conditions in this low-energy environment have been relatively stable during the recent geologic history of the estuary.

  2. Water-quality data from continuously monitored sites in the Pamlico and Neuse River estuaries, North Carolina, 1990-91

    USGS Publications Warehouse

    Garrett, Ronald G.

    1992-01-01

    Water quality measurements were made at six sites in or near North Carolina's Pamlico River estuary and at five sites in or near the Neuse River estuary. Measurements taken at 15-minute intervals included near-surface and near-bottom specific conductance; near-surface water temperature; and near-surface, mid-depth, and near-bottom dissolved-oxygen concentrations. In the Pamlico River estuary, salinities generally ranged from near zero to about 20 parts per thousand during the period April 1989 through September 1991; however, unnaturally high salinities (up to about 51 parts per thousand) were observed at one site on July 11, 1990. Recorded water temperatures in the Pamlico River were between 0 and 33 degrees Celsius during the measurement period. Dissolved-oxygen concentrations ranged from less than 1 to 20 milligrams per liter. In the Neuse River estuary, salinities ranged from less than 0.1 to nearly 33 parts per thousand between May 1989 and September 1991. During the same period, recorded water temperatures in this estuary were between 0 and 33 degrees Celsius. Dissolved-oxygen concentrations ranged from less than 1 to 21 milligrams per liter. Instantaneous values for selected periods are summarized in a series of box plots. Daily mean values of salinity, water temperature, dissolved-oxygen concentrations, and dissolved oxygen, percent saturation, are presented in tables and graphs, as are 5-day mean values for day and night conditions. This is the second in a series of reports summarizing water quality data obtained from these continuously monitored sites.

  3. Surface-water hydrology and salinity of the Anclote River estuary, Florida

    USGS Publications Warehouse

    Fernandez, Mario

    1990-01-01

    Direct measurements of streamflow, tides, and salinity in the Anclote River Estuary, Florida were made during the period January 1984 through May 1986; historical streamflow was compared to that measured during the study; the influence of well-field pumpage on streamflow was evaluated; and regression relations between salinity, tide, and average daily streamflow were developed. Mean monthly streamflows during the study period generally were lower than the corresponding long-term monthly averages yet representative of flows that typically enter the estuary. The influence of pumpage from individual well fields in or near the basin on streamflow was not statistically significant; the influence of total well-field pumpage, however, was significant at the 5% level. The upstream daily location of 0.44-, 5.0-, 10-, and 18-parts-per-thousand (ppt) salinity was quantified using multiple regression techniques. Streamflow used in the analysis ranged from 2.3 to 263 cu ft/sec, and high tides ranged from 0.25 ft below to 2.76 ft above sea level. Vertical salinity profiles indicated partially to well-mixed conditions throughout the estuary during the study period. Results of the regression analyses show that streamflow has a large effect on the location of the saltwater- freshwater interface (defined as 0.44 ppt salinity) as well as water having a salinity of 5.0 ppt. The location of water having salinities greater than 5.0 ppt is affected increasingly by tide, with a corresponding decrease in effect by streamflow. (USGS)

  4. 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

  5. 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.

  6. 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

  7. 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

  8. 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.

  9. 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.

  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. 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.

  12. 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…

  13. Quantitative assessment of benthic food resources for juvenile Gulf sturgeon, Acipenser oxyrinchus desotoi in the Suwannee River estuary, Florida, USA

    USGS Publications Warehouse

    Brooks, R.A.; Sulak, K.J.

    2005-01-01

    Gulf sturgeon, Acipenser oxyrinchus desotoi, forage extensively in the Suwannee River estuary following emigration out of the Suwannee River, Florida. While in the estuary, juvenile Gulf sturgeon primarily feed on benthic infauna. In June-July 2002 and February-April 2003, random sites within the estuary were sampled for benthic macrofauna (2002 n = 156; 2003 n = 103). A mean abundance of 2,562 ind m-2 (SE ?? 204) was found in the summer, with significantly reduced macrofaunal abundance in the winter (mean density of 1,044 ind m-2, SE ?? 117). Benthic biomass was significantly higher in the summer with an average summer sample dry weight of 5.92 g m-2 (SE ?? 0.82) compared to 3.91 g m-2 (SE ?? 0.67) in the winter. Amphipods and polychaetes were the dominant taxa collected during both sampling periods. Three different estimates of food availability were examined taking into account principal food item information and biomass estimates. All three estimates provided a slightly different view of potential resources but were consistent in indicating that food resource values for juvenile Gulf sturgeon are spatially heterogeneous within the Suwannee River estuary. ?? 2005 Estuarine Research Federation.

  14. Bacterial polycyclic aromatic hydrocarbon ring-hydroxylating dioxygenases in the sediments from the Pearl River estuary, China.

    PubMed

    Wu, Peng; Wang, You-Shao; Sun, Fu-Lin; Wu, Mei-Lin; Peng, Ya-lan

    2014-01-01

    Bacterial community compositions were characterized using denaturing gradient gel electrophoresis analysis of bacterial 16S rRNA gene in the sediments of the Pearl River estuary. Sequencing analyses of the excised bands indicated that Gram-negative bacteria, especially Gammaproteobacteria, were dominant in the Pearl River estuary. The diversity of polycyclic aromatic hydrocarbon ring-hydroxylating dioxygenase (PAH-RHD) gene in this estuary was then assessed by clone library analysis. The phylogenetic analyses showed that all PAH-RHD gene sequences of Gram-negative bacteria (PAH-RHD[GN]) were closely related to the nagAc gene described for Ralstonia sp. U2 or nahAc gene for Pseudomonas sp. 9816-4, while the PAH-RHD gene sequences of Gram-positive bacteria (PAH-RHD[GP]) at sampling site A1 showed high sequence similarity to the nidA gene from Mycobacterium species. Meanwhile, molecular diversity of the two functional genes was higher at the upstream of this region, while lower at the downstream. Redundancy analysis indicated that environmental factors, such as NH₄--N, ∑PAHs, pH, SiO₃--Si, and water depth, affected the distribution of the PAH-RHD[GN] gene in the Pearl River estuary.

  15. 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...

  16. Policy change driven by an AIS-assisted marine emission inventory in Hong Kong and the Pearl River Delta

    NASA Astrophysics Data System (ADS)

    Ng, Simon K. W.; Loh, Christine; Lin, Chubin; Booth, Veronica; Chan, Jimmy W. M.; Yip, Agnes C. K.; Li, Ying; Lau, Alexis K. H.

    2013-09-01

    A new exhaust emission inventory of ocean-going vessels (OGVs) was compiled for Hong Kong by using Automatic Identification System (AIS) data for the first time to determine typical main engine load factors, through vessel speed and operation mode characterization. It was found that in 2007, container vessel was the top emitting vessel type, contributing 9,886, 11,480, 1,173, 521 and 1166 tonnes of SO2, NOx, PM10, VOC and CO, respectively, or about 80%-82% of the emissions. The top five, which also included ocean cruise, oil tanker, conventional cargo vessel and dry bulk carrier, accounted for about 98% of emissions. Emission maps, which add a new spatial dimension to the inventory, show the key emission hot spots in Hong Kong and suggest that a significant portion of emissions were emitted at berth. Scientific evidence about the scale and distribution of ship emissions has contributed in raising public awareness and facilitating stakeholder engagement about the issue. Fair Winds Charter, the world's first industry-led voluntary emissions reduction initiative, is a perfect example of how careful scientific research can be used in public engagement and policy deliberation to help drive voluntary industry actions and then government proposals to control and regulate marine emissions in Hong Kong and the Pearl River Delta region.

  17. 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.

  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. 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.

  20. 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

  1. 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)

  2. 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.

  3. 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

  4. /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)

  5. 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.

  6. 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

  7. Dissolved Copper, Nickel and Lead in Tampamachoco Lagoon and Tuxpan River Estuary in the SW Gulf of Mexico.

    PubMed

    Garduño Ruiz, E P; Rosales Hoz, L; Carranza Edwards, A

    2016-10-01

    In order to estimate the effects of a thermal power plant, physicochemical parameters and the concentrations of copper, nickel and lead were evaluated in water from both Tampamachoco Lagoon and the estuary of the Tuxpan River. Average salinities were 33.66 ups in the lagoon area, 32.77 ups in the channel that joins the lagoon and the river, and 24.74 ups in the river estuary. Total average metal concentrations were 21.95 for Cu, 29.67 for Ni and 4.31 µ/L for Pb. Sampling point 1 and samples from the bottom water of the lagoon present the highest salinities and concentrations of suspended matter, TOC, Cu, Ni and Pb.These high values may be associated with the infiltration of sea water either from plant operation or from the channel that connects the lagoon with the sea. PMID:27544675

  8. The distribution and partitioning of common antibiotics in water and sediment of the Pearl River Estuary, South China.

    PubMed

    Liang, Ximei; Chen, Baowei; Nie, Xiangping; Shi, Zhen; Huang, Xiaoping; Li, Xiangdong

    2013-09-01

    Antibiotics released into the aquatic environment play an important role in the spread of antibiotic resistance. In the Pearl River Estuary (PRE) and the coastal zone, the concentrations of antibiotics decreased from the Pearl River to the estuary, suggesting that antibiotics primarily originated from river tributaries and terrigenous sources. Within the PRE area, the concentrations of antibiotics in water were higher in the west coast than the east side, reflecting the high density of anthropogenic activities and hydraulic conditions along the west riverbank. Seasonal variations were also observed for most of detected antibiotics in water. The pseudo-partitioning coefficient of norfloxacin had a good correlation with the TOC content of sediments, as did erythromycin-H2O with the pH of water. The results suggest that environmental conditions can significantly affect the distribution of antibiotics between water and sediment.

  9. Impact of Mississippi River freshwater reintroduction on enhancing marsh accretionary processes in a Louisiana estuary

    NASA Astrophysics Data System (ADS)

    DeLaune, R. D.; Jugsujinda, A.; Peterson, G. W.; Patrick, W. H.

    2003-11-01

    To counteract extensive wetland loss a series of diversion projects have been implemented to introduce freshwater and sediment from the Mississippi River into Louisiana coastal wetlands. To keep pace with increases in water level due to subsidence Louisiana coastal marshes must vertically accrete through the accumulation of both organic matter and mineral sediment. The impact of Mississippi River freshwater diversion on enhancing vertical marsh accretion (mineral and organic matter accumulation) was examined in Breton Sound estuary, a coastal wetland experiencing marsh deterioration as result of subsidence and salt water intrusion. Using 137Cs dating and artificial marker horizons, increases in the rate of vertical marsh accretion were measured at marsh sites along a spatial gradient which has been receiving diverted water from the Mississippi River (Caernarvon diversion) since 1991. Vertical accretion and accumulation of mineral sediment organic matter and nutrients in the marsh soil profile, increased at marsh sites receiving freshwater and sediment input. Iron and manganese content of the marsh surface sediment were shown to be an excellent signature of riverine sediment deposition. Soil extractable phosphorus was higher and extractable sodium was lower at sites nearest freshwater and sediment input. Results demonstrated that freshwater diversion through sediment input and lowering of salinity will enhance marsh accretion and stability, slowing or reversing the rate of wetland loss.

  10. 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

  11. 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.

  12. 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).

  13. Nitrogen cycle of a typical Suaeda salsa marsh ecosystem in the Yellow River estuary.

    PubMed

    Mou, Xiaojie; Sun, Zhigao; Wang, Lingling; Wang, Chuanyuan

    2011-01-01

    The nitrogen (N) biological cycle of the Suaeda salsa marsh ecosystem in the Yellow River estuary was studied during 2008 to 2009. Results showed that soil N had significant seasonal fluctuations and vertical distribution. The N/P ratio (15.73 +/- 1.77) of S. salsa was less than 16, indicating that plant growth was limited by both N and P. The N absorption coefficient of S. salsa was very low (0.007), while the N utilization and cycle coefficients were high (0.824 and 0.331, respectively). The N turnover among compartments of S. salsa marsh showed that N uptake from aboveground parts and roots were 2.539 and 0.622 g/m2, respectively. The N translocation from aboveground parts to roots and from roots to soil were 2.042 and 0.076 g/m2, respectively. The N translocation from aboveground living bodies to litter was 0.497 g/m2, the annual N return from litter to soil was far less than 0.368 g/m2, and the net N mineralization in topsoil during the growing season was 0.033 g/m2. N was an important limiting factor in S. salsa marsh, and the ecosystem was classified as unstable and vulnerable. S. salsa was seemingly well adapted to the low-nutrient status and vulnerable habitat, and the nutrient enrichment due to N import from the Yellow River estuary would be a potential threat to the S. salsa marsh. Excessive nutrient loading might favor invasive species and induce severe long-term degradation of the ecosystem if human intervention measures were not taken. The N quantitative relationships determined in our study might provide a scientific basis for the establishment of effective measures.

  14. A long-term analysis of E. coli concentrations in a highly urbanised estuary: The Yarra River, Australia

    NASA Astrophysics Data System (ADS)

    McCarthy, D. T.; Daly, E.; Deletic, A.

    2011-12-01

    Long term water quality data have been used to understand the fate of E. coli in the catchment of the Yarra River flowing through the city of Melbourne in south-east Australia. Particular attention is dedicated to the estuary of the river, which, being in the centre of the city, is an area of recreational activities with strict water quality requirements to limit human health risks. Two data sets of E. coli concentrations in several sites along the river and some of the tributaries are used. One data set of monthly data in five sites starts in 1994 and the other of weekly data in 12 sites starts in 2005. Water quality data from some stormwater drains are also available in both dry and wet weather; in particular, water samples from two main drains have been collected three times a week since March 2011. These data are analysed i) to identify possible patterns in spatial and temporal variability of concentrations, ii) to understand the relationship between E. coli concentrations and other pollutants, and iii) to quantify the importance of stormwater drains in determining the magnitude of E. coli concentrations in the estuary. Median values of E.coli concentrations in each site are shown to be rather stationary in time, without evident seasonal and inter-annual variability, in spite of the large variability the river discharge experienced in the past few years. The median and the variability of the concentrations increase slightly as moving downstream with larger variability in the estuary. A multiple linear regression analysis showed that the E. coli concentrations along the river and in the estuary are positively correlated with phosphorus. The relationship with phosphorus is consistent with water quality samples independently collected and analysed in two sites in the estuary in 2011, but was not detected in two tributaries and in the stormwater drains. The data are used in a mass balance equation to estimate E. coli inputs into and outputs from the estuary as well

  15. 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.

  16. Response of the turbidity maximum zone in the Yangtze River Estuary due to human activities during the dry season.

    PubMed

    Chen, Xiaofeng; Shen, Zhenyao; Yang, Ye

    2016-09-01

    The interaction between a river and the sea results in a turbidity maximum zone (TMZ) within the estuary, which has a great impact on the local ecosystem. In the Yangtze River Estuary, the magnitude and extent of the TMZ vary with water discharge. In this study, the cumulative human activity altered the water discharge regime from the river to the estuary. In the post-Three Gorges Dam (TGD) period, water discharge increased by 35.10 % at Datong in February compared with that in the pre-TGD period. The effects of water discharge variation on the characteristics of the TMZ were analyzed during spring and neap tidal periods using the three-dimensional environmental fluid dynamic code (EFDC) model. The area of the TMZ decreased by 3.11 and 17.39 % during neap and spring tides, respectively. In addition, the upper limit of the TMZ moved 11.68 km seaward during neap tide, whereas the upper limit of the TMZ in the upstream and downstream areas moved seaward 9.65 and 2.34 km, respectively, during spring tide. These findings suggest that the area and location of the TMZ are more sensitive to upstream runoff during spring tide than during neap tide. These changes in the TMZ will impact the biochemical processes in the Yangtze River Estuary. In the foreseeable future, the distribution characteristic of TMZ will inevitably change due to variations in the Yangtze River discharge resulting from new human activities (i.e., new dams), which are being constructed upstream in the Yangtze River system.

  17. Response of the turbidity maximum zone in the Yangtze River Estuary due to human activities during the dry season.

    PubMed

    Chen, Xiaofeng; Shen, Zhenyao; Yang, Ye

    2016-09-01

    The interaction between a river and the sea results in a turbidity maximum zone (TMZ) within the estuary, which has a great impact on the local ecosystem. In the Yangtze River Estuary, the magnitude and extent of the TMZ vary with water discharge. In this study, the cumulative human activity altered the water discharge regime from the river to the estuary. In the post-Three Gorges Dam (TGD) period, water discharge increased by 35.10 % at Datong in February compared with that in the pre-TGD period. The effects of water discharge variation on the characteristics of the TMZ were analyzed during spring and neap tidal periods using the three-dimensional environmental fluid dynamic code (EFDC) model. The area of the TMZ decreased by 3.11 and 17.39 % during neap and spring tides, respectively. In addition, the upper limit of the TMZ moved 11.68 km seaward during neap tide, whereas the upper limit of the TMZ in the upstream and downstream areas moved seaward 9.65 and 2.34 km, respectively, during spring tide. These findings suggest that the area and location of the TMZ are more sensitive to upstream runoff during spring tide than during neap tide. These changes in the TMZ will impact the biochemical processes in the Yangtze River Estuary. In the foreseeable future, the distribution characteristic of TMZ will inevitably change due to variations in the Yangtze River discharge resulting from new human activities (i.e., new dams), which are being constructed upstream in the Yangtze River system. PMID:27287491

  18. 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

  19. [Kinetics of zooplankton in an aquatic continuum: from the Marne River and reservoir to the Seine estuary].

    PubMed

    Akopian, Maïa; Garnier, Josette; Pourriot, Roger

    2002-07-01

    A study was carried out within a 700-km river sector, including three types of ecosystems (a reservoir, a river and its estuary) to characterise the major features of zooplankton communities in the Seine Basin. In rivers, zooplankton biomass becomes significant only when the growth rate of the organisms is higher than the dilution rate (4-5th orders rivers, according to River Continuum Concept). Upstream, short residence times favour the development of small species (Rotifers) with low individual body weight and biomass. Conversely, larger species (microcrustaceans) develop more downstream, where increased residence time leads to autochthonous production (Riverine Productivity Model). Such a pattern is greatly modified by human impact. Zooplankton input from the Marne reservoir represents one type of disruption in the general upstream-downstream trend (according to the Serial Discontinuity Concept). This reservoir is a source of microcrustaceans; they rapidly disappear mainly through fish predation, and therefore have little impact on the river phytoplankton. Discontinuities, such as confluences, have a relatively small effect on the stock of zooplankton with regard to the water release from the reservoir, but they persist more downstream, because they have the same lotic origin. A few microhabitats with macrophytes play a small role for this canalised river, but they can modify locally the plankton community structure and composition. As a whole, the flux of zooplankton rises exponentially, whereas discharge increases linearly from upstream (4th order) to downstream (8th order). In the canalised sectors, Dreissena larvae build up an important biomass, adding to that of the zooplankton sensu stricto. Especially abundant in the downstream sector of the Marne and Seine Rivers, the larvae show a widespread colonisation of the benthic substrates by the adult Dreissena. One of the largest mussel colonies in the middle estuary can contribute to a rapid decrease of

  20. 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

  1. 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

  2. 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

  3. Upstream Freshwater and Terrestrial Sources Are Differentially Reflected in the Bacterial Community Structure along a Small Arctic River and Its Estuary

    PubMed Central

    Hauptmann, Aviaja L.; Markussen, Thor N.; Stibal, Marek; Olsen, Nikoline S.; Elberling, Bo; Bælum, Jacob; Sicheritz-Pontén, Thomas; Jacobsen, Carsten S.

    2016-01-01

    Glacier melting and altered precipitation patterns influence Arctic freshwater and coastal ecosystems. Arctic rivers are central to Arctic water ecosystems by linking glacier meltwaters and precipitation with the ocean through transport of particulate matter and microorganisms. However, the impact of different water sources on the microbial communities in Arctic rivers and estuaries remains unknown. In this study we used 16S rRNA gene amplicon sequencing to assess a small river and its estuary on the Disko Island, West Greenland (69°N). Samples were taken in August when there is maximum precipitation and temperatures are high in the Disko Bay area. We describe the bacterial community through a river into the estuary, including communities originating in a glacier and a proglacial lake. Our results show that water from the glacier and lake transports distinct communities into the river in terms of diversity and community composition. Bacteria of terrestrial origin were among the dominating OTUs in the main river, while the glacier and lake supplied the river with water containing fewer terrestrial organisms. Also, more psychrophilic taxa were found in the community supplied by the lake. At the river mouth, the presence of dominant bacterial taxa from the lake and glacier was unnoticeable, but these taxa increased their abundances again further into the estuary. On average 23% of the estuary community consisted of indicator OTUs from different sites along the river. Environmental variables showed only weak correlations with community composition, suggesting that hydrology largely influences the observed patterns. PMID:27708629

  4. Managing flow, sediment, and hydropower regimes in the Sre Pok, Se San, and Se Kong Rivers of the Mekong basin

    NASA Astrophysics Data System (ADS)

    Wild, Thomas B.; Loucks, Daniel P.

    2014-06-01

    The Lancang/Mekong River Basin is presently undergoing a period of rapid hydropower development. In its natural undeveloped state, the river transports about 160 million metric tons of sediment per year, maintaining the geomorphologic features of the basin, sustaining habitats, and transporting the nutrients that support ecosystem productivity. Despite the importance of sediment in the river, currently little attention is being paid to reservoir sediment trapping. This study is devoted to assessing the potential for managing sediment and its impact on energy production in the Se San, Sre Pok, and Se Kong tributaries of the Mekong River. These tributaries drain a set of adjacent watersheds that are important with respect to biodiversity and ecological productivity, and serve as a significant source of flow and sediment to the mainstream Mekong River. A daily sediment transport model is used to assess tradeoffs among energy production and sediment and flow regime alteration in multiple reservoir systems. This study finds that eventually about 40%-80% of the annual suspended sediment load may be trapped in reservoirs. Clearly, these reservoirs will affect the rivers' sediment regimes. However, even after 100 years of simulated sedimentation, reservoir storage capacities and hydropower production at most reservoir sites are not significantly reduced. This suggests that the strongest motivation for implementing measures to reduce trapped sediment is their impact not on hydropower production but on fish migration and survival and on sediment-dependent ecosystems such as the Vietnam Delta and Cambodia's Tonle Sap Lake.

  5. 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.

  6. 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.

  7. 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.

  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. Quantifying Distribution of Recent Sediment Using XRF Analysis and Seismic Data in the Hudson River Estuary

    NASA Astrophysics Data System (ADS)

    Haberman, M.; Nitsche, F. O.; Kenna, T. C.; Sands, E.; Bell, R. E.; Ryan, W. B.

    2006-12-01

    Detailed understanding of sediment dynamics and associated contaminants in rivers and estuaries is essential for effective management as well as estimating sediment budgets and modeling sediment transport. While acoustic techniques provide extremely high spatial resolution, they are limited in their ability to provide useful temporal information with respect to depositional sites. This information is typically provided by collection of sediment core samples from the area of interest followed by expensive and time-consuming geochemical analyses to establish deposition chronologies, which are usually obtained for only a small subset of the collected cores. At present, the level at which we can obtain detailed spatial information far exceeds our ability to obtain temporal information. Here we present an integrated approach using data collected from Haverstraw Bay, located in the Hudson River Estuary. We combine a detailed interpretation of high-resolution seismic data that were collected as part of the Hudson River Benthic Mapping Project issued by the New York State DEC with lead distributions measured via field portable X-ray Fluorescence Spectrometry on over fifty sediment cores. We analyzed a dense grid (80 x 160 m) of high-resolution, single-channel seismic lines using a seismic interpretation software package and traced the bottom and top of the recent sediment layer. Using lead concentrations elevated above natural background as a proxy for identifying sediments impacted by 20th century industrial activities, we were able to verify the presence and thickness of recent (post-1930) sediments. Combining the two datasets, we obtained a detailed grid representing the thickness of recent sediments in our study area. The grid was then exported to a GIS software package for interpretation and calculation of the distribution (areas and volume) of recent sediments. Using the age constraints from the XRF-lead (verified by Cs-137 and Pb-210 measurements), we can also

  10. 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

  11. The Across Shelf and Hudson River Estuary: a Synoptic Glimpse of Hydrographic, Biogeochemical, and Biological Processes

    NASA Astrophysics Data System (ADS)

    McGillis, W.; Gallager, S.; Geyer, W. R.; Miller, E.; Salisbury, J.; Vandemark, D.; Katz, D.; McNeil, C.

    2004-12-01

    In July 2004, oceanographic data were measured from the shelf edge to fresh water in the Hudson River estuary onboard the research vessel Tioga by researchers from the Woods Hole Oceanographic Institution, the Lamont-Doherty Earth Observatory at Columbia University, the University of New Hampshire, and the University of Rhode Island. Multi-disciplinary observations including parts of the life cycle and carbon cycle were performed. Data included surface temperature, salinity, fluorescence, turbidity, dissolved oxygen, nitrogen, the partial pressure of carbon dioxide, dissolved inorganic carbon, dissolved organic carbon, colored dissolved organic matter, phytoplankton, zooplankton, and a focus on zebra mussel larvae. The very large gradients observed from shelf waters to fresh water provided a wide range of environmental conditions governing the carbonate system and the life cycle of phytoplankton and larvae. This unique suite of measurements provides insight into the transport, distribution, and dynamics of the physiology of the Hudson River plume. The relationship between hydrographic conditions, biogeochemistry, and biology will be discussed.

  12. 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.

  13. Water quality of the tidal Potomac River and estuary hydrologic data report, 1980 water year

    USGS Publications Warehouse

    Blanchard, Stephen; Coupe, R.H.; Woodward, J.C.

    1982-01-01

    This report contains data on the physical and chemical properties measured in the Tidal Potomac River and Estuary during the 1980 Water Year. Data were collected routinely at five stations, and periodically at 17 stations including three stations near the mouth of the Potomac River in Chesapeake Bay. Each of the five stations represent a cross section through which the transport of selected dissolved and suspended materials can be computed. The remaining stations represent locations at which data were collected for special synoptic studies such as salt water migration, and dissolved oxygen dynamics. Routinely, samples were analyzed for silica, nitrogen, phosphorus, chlorophyll-a, pheophytin, and suspended sediment. Additional samples were analyzed for organic carbon, calcium, manganese, magnesium, sodium, alkalinity, sulfate, iron, potassium, chloride, fluoride, seston, algal growth potential, adenosine triphosphate, nitrifying bacteria and dissolved-solids residue. In addition, solar radiation measurements and in-situ measurements of dissolved oxygen, specific conductance, pH, temperature, and Secchi disk transparency are reported. (USGS)

  14. Seasonal and spatial distribution of several endocrine-disrupting compounds in the Douro River Estuary, Portugal.

    PubMed

    Ribeiro, Cláudia; Tiritan, Maria Elizabeth; Rocha, Eduardo; Rocha, Maria João

    2009-01-01

    Recent studies in the Douro River estuary show signs of pollution in the area and of fish endocrine disruption. However, the chemical nature of the local contamination has not been fully investigated nor have studies checking for the simultaneous presence of endocrine-disrupting chemicals (EDCs), either of animal (estrone, E1; estradiol, E2), pharmaceutical (17alpha-ethynylestradiol, EE2), vegetal (daidzein, DAID; genistein, GEN; biochanin A, BIO-A), or industrial (bisphenol A, BPA; 4-octylphenol, 4-OP; 4-nonylphenol, 4-NP) origins. Thus, the main objective of this study was to examine the presence of these EDCs in estuarine water samples collected, in every season of the year, at nine sampling stations along the estuarine gradient. All samples were processed by two-step solid-phase extraction (Oasis HLB followed by silica) prior to high-performance liquid chromatography with diode-array detection (HPLC-DAD) and gas chromatography-mass spectrometry (GC-MS) analyses. The current data showed that E1 and EE2, all phytoestrogens, and BPA were identified and measured in this estuary. In contrast, 4-OP was only detected by GC-MS and E2 and 4-NP were not found. Additionally, E1 (up to 112.9 ng/L) and EE2 (up to 101.9 ng/L) were both measured in biologically hazardous amounts in winter. In the year sampled, the phytoestrogens suggested a possible seasonal pattern of fluctuation. Both DAID (up to 888.4 ng/L) and GEN (183.6 ng/L) were maximal in early summer, whereas BIO-A (up to 191.4 ng/L) reached its highest concentrations in winter. BPA (up to 10.7 microg/L) also attained highest levels in winter. In December 2005, it is hypothesized that E1, EE2, and BPA concentrations were atypically high due to current drought conditions. Almost all assayed EDCs existed in all seasons and, therefore, might have contributed to endocrine disruption of aquatic animals, previously documented by the high rate of ovotestis in fish caught in this estuary. PMID:18368434

  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

    2016-09-01

    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.

  16. Simulation of hydrodynamics and solute transport in the Neuse River estuary

    USGS Publications Warehouse

    Robbins, Jeanne C.; Bales, Jerad

    1995-01-01

    An investigation was conducted to characterize flow, circulation, and transport in the Neuse River estuary, North Carolina. The study included a detailed field-measurement program and the calibration, validation, and application of a physically realistic numerical model of hydro- dynamics and transport through a 40-kilometer reach of the estuary. Water level, salinity, water temperature, wind speed and direction, current velocity, and bathymetric data were collected during March 1988 through September 1992. Additional data from pre-existing continuous-record streamflow gaging stations and meteorological stations also were used. A two-dimensional, vertically averaged hydrodynamic and solute transport model was applied to the study reach. The model domain was discretized into 200- by 200-meter computational cells. Model calibration was achieved through adjustment of model parameters for the period June 1-24, 1991. Additional simulations for periods in 1989 and 1991 were run to validate the model. The model was calibrated and validated for water levels ranging from -0.104 to 0.908 meters, salinities ranging from 2.8 to 22.0 parts per thousand, and wind speed from calm to 9 meters per second. The model was tested for stratified and unstratified conditions. Simulated and observed level, salinity, and velocity data were used to evaluate the model. The calibrated model was applied to simulate flows, circulation, and salinity distributions for four simulation periods in 1989 and 1991. Comparisons of simulated results for a period in June 1991 were made between the Neuse and Pamlico models to characterize differences between the two systems.

  17. 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.

  18. Mercury profiles in sediments of the Pearl River Estuary and the surrounding coastal area of South China.

    PubMed

    Shi, Jian-bo; Ip, Carman C M; Zhang, Gan; Jiang, Gui-bin; Li, Xiang-dong

    2010-05-01

    The spatial and temporal variations of mercury (Hg) in sediments of the Pearl River Estuary (PRE) and the surrounding coastal area (South China Sea) were studied. In surface sediments, the concentrations of Hg ranged from 1.5 to 201ng/g, with an average of 54.4ng/g, displaying a decreasing trend with the distance from the estuary to the open sea. This pattern indicates that the anthropogenic emissions from the Pearl River Delta (PRD) region are probably the main sources of Hg in this coastal region. Using the (210)Pb dating technique, the historical changes in the concentrations and influxes of Hg in the last 100 years were also investigated. The variations in Hg influxes in sediment cores obviously correlate with the economic development and urbanization that has occurred the PRD region, especially in the last three decades.

  19. 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

  20. 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

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

    PubMed Central

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

    2013-01-01

    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

  2. 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

  3. 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.

  4. Tidal resuspension and transport processes of fine sediment within the river plume in the partially-mixed Changjiang River estuary, China: A personal perspective

    NASA Astrophysics Data System (ADS)

    Shi, John Z.

    2010-09-01

    This paper summarizes process-oriented field and numerical studies undertaken on the river plume in the partially-mixed Changjiang River estuary. Both estuarine circulation and tidal asymmetry are of great importance to the fine sediment processes. Mean suspended sediment concentration (C¯) and bottom shear stress are the dominant physical parameters controlling the flocculation and settling velocities ( ws) of mud flocs in suspension. Two important physical processes are revealed by acoustic imaging, i.e. (i) the near-bed impulsive resuspension and (ii) the transport processes driven by fine sediment-induced plumes during a spring tide. A turbidity maximum, associated with a suspended sediment front, is observed. Its formation is caused mainly by tidal asymmetry, near-bed periodic tidal resuspension and turbulence suppression by suspension/salinity stratifications. A conceptual sketch of the turbidity maximum is cautiously proposed for the Changjiang River estuary. Four different settling velocity equations, taking flocculation into account, have different effects on the modeled concentration profiles of fine sediment: apparently, Cao and Wang (1994, pp. 252-253) would be the best for spring tide and Thorn (1982, Fig. 3/page 66) for neap tide. Both tidal acceleration and tidal deceleration have strong effects on the concentration profiles of fine sediment within the Changjiang River estuary.

  5. 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.

  6. 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

  7. PAHs in sediment cores at main river estuaries of Chaohu Lake: implication for the change of local anthropogenic activities.

    PubMed

    Ren, Chen; Wu, Yaketon; Zhang, Shuo; Wu, Liang-Liang; Liang, Xiao-Guo; Chen, Tian-Hu; Zhu, Cheng-Zhu; Sojinu, Samuel O; Wang, Ji-Zhong

    2015-02-01

    In the present study, 28 polycyclic aromatic hydrocarbons (PAHs) were investigated in four sediment cores collected from the main river estuaries of Chaohu Lake, one of the severely polluted lakes in China. The results indicate that elevated concentrations of total PAHs (Σ28PAH) were found in the samples from the estuary of Nanfei River (ENF), considering BaP-based total toxicity equivalent (TEQ-BaP) and toxic unit (TU) results; there are potential adverse environmental implications. The total organic carbon (TOC) played an important role on the accumulation of PAHs at ENF and the estuary of Tongyang River (ETY). The predominant PAHs are high molecular weight (HMW) homologous for all samples; as a result, industrial wastewater from a steel company is expectedly the key source of PAHs in ENF, while coke consumption would be the important source of PAHs at other three sampling sites. Vertical distribution of PAHs in the sediment cores could be explained by the local social and economic activities. Furthermore, a minor variation of PAH composition in the sediment core could be justified by the stable structure of energy consumption in the Anhui Province. These results justify the need for further enhancement of industrial wastewater treatment and development of renewable energies which are the key factors on the control of PAH pollution in China.

  8. 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.

  9. The biogeochemistry of inorganic carbon and nutrients in the Pearl River estuary and the adjacent Northern South China Sea

    NASA Astrophysics Data System (ADS)

    Cai, Wei-Jun; Dai, Minhan; Wang, Yongchen; Zhai, Weidong; Huang, Tao; Chen, Shuitu; Zhang, Fan; Chen, Zhaozhang; Wang, Zhaohui

    2004-08-01

    The Zhu-jiang (Pearl River) estuary and its adjacent continental shelf in the Northern South China Sea (SCS) is unique in that its drainage basin is located entirely in a subtropical zone with heavy population development, and therefore represents an important regime for biogeochemical studies on how large rivers influence continental shelves. The near-zero salinity end member has high nutrient concentrations (silicate 130-140 μM, nitrate 75-100 μM and phosphate 0.2-1.2 μM) and relatively high total dissolved inorganic carbon (DIC) (1500 μM) and alkalinity (˜1650 μM) values. Water column DIC, alkalinity, and nutrient in the estuary are largely controlled by mixing of waters from different tributaries with different drainage basin chemistry, anthropogenic influence, and degree of estuarine recycling. Biological uptake of nutrients and inorganic carbon occur in the outer estuary and inner shelf areas supported by riverine nutrients. The N/P and Si/P ratios are generally very high within the estuary. The summertime area-integrated biological production rate of 0.8 gC m -2 d -1 is estimated based on the depletion of DIC and alkalinity relative to the conservative mixing line and a plume travel time. This estimate agrees reasonably well with 14C based primary production rates (PP) and with that from effective river phosphate flux. Biological production decreases about 10-fold in the open continental shelf and slope and is largely supported by mixing with subsurface water. A comparison of DIC, phosphate, and nitrate concentrations in the surface mixing layer and at the bottom of the euphotic zone with the 14C-based PP (0.13 gC m -2 d -1) suggests that the surface water residence time in the Northern SCS is ˜1.3 years. The N/P, Si/P, and Si/C ratios are 15, 25, and 0.15, respectively. The subtropical Pearl River study is also compared to other large rivers with regard to differences in both natural processes (i.e., weathering rates) and anthropogenic influences (i

  10. [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.

  11. 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.

  12. 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

  13. 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

  14. 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

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

    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.

  17. [Assessment of ecosystem energy flow and carrying capacity of swimming crab enhancement in the Yellow River estuary and adjacent waters].

    PubMed

    Lin Qun; Wang, Jun; Li, Zhong-yi; Wu, Qiang

    2015-11-01

    Stock enhancement is increasingly proved to be an important measure of the fishery resources conservation, and the assessment of carrying capacity is the decisive factor of the effects of stock enhancement. Meanwhile, the variations in the energy flow patterns of releasing species and ecosystem were the basis for assessing carrying capacity of stock enhancement. So, in the present study, based on the survey data collected from the Yellow River estuary and adjacent waters during 2012-2013, three Ecopath mass-balance models were established in June, August and October, and the variations in ecosystem energy flow in these months were analyzed, as well as the assessment of carrying capacity of swimming crab enhancement. The energy flow mainly concentrated on trophic level I-III in Yellow River estuary and adjacent waters, and was relatively less on trophic level IV or above. The system flow proportion on the trophic level I was the highest in June, and was the lowest in August. The highest system flow proportion on the trophic level II was found in August, and the lowest in June. The relative and absolute energy flow of swimming crab mainly concentrated on the trophic level III, and the mean trophic level of swimming crab among June, August and October were 3.28. Surplus production was relatively higher in Yellow River estuary and adjacent waters, the highest value was found in June, and the lowest value in August. The ratios of total primary production/total respiration (TPP/TR) were 5.49, 2.47 and 3.01 in June, August and October, respectively, and the ratios of total primary production/total biomass (TPP/B) were 47.61, 33.30 and 29.78, respectively. Combined with the low Finn' s cycling index (FCI: 0.03-0.06), these changes indicated that the Yellow River estuary ecosystem was at an early development stage with higher vulnerability. The energy conversion efficiency of system was from 7.3% to 11.5%, the mean trophic levels of the catch were 3.23, 2.97 and 2.82 in

  18. [Assessment of ecosystem energy flow and carrying capacity of swimming crab enhancement in the Yellow River estuary and adjacent waters].

    PubMed

    Lin Qun; Wang, Jun; Li, Zhong-yi; Wu, Qiang

    2015-11-01

    Stock enhancement is increasingly proved to be an important measure of the fishery resources conservation, and the assessment of carrying capacity is the decisive factor of the effects of stock enhancement. Meanwhile, the variations in the energy flow patterns of releasing species and ecosystem were the basis for assessing carrying capacity of stock enhancement. So, in the present study, based on the survey data collected from the Yellow River estuary and adjacent waters during 2012-2013, three Ecopath mass-balance models were established in June, August and October, and the variations in ecosystem energy flow in these months were analyzed, as well as the assessment of carrying capacity of swimming crab enhancement. The energy flow mainly concentrated on trophic level I-III in Yellow River estuary and adjacent waters, and was relatively less on trophic level IV or above. The system flow proportion on the trophic level I was the highest in June, and was the lowest in August. The highest system flow proportion on the trophic level II was found in August, and the lowest in June. The relative and absolute energy flow of swimming crab mainly concentrated on the trophic level III, and the mean trophic level of swimming crab among June, August and October were 3.28. Surplus production was relatively higher in Yellow River estuary and adjacent waters, the highest value was found in June, and the lowest value in August. The ratios of total primary production/total respiration (TPP/TR) were 5.49, 2.47 and 3.01 in June, August and October, respectively, and the ratios of total primary production/total biomass (TPP/B) were 47.61, 33.30 and 29.78, respectively. Combined with the low Finn' s cycling index (FCI: 0.03-0.06), these changes indicated that the Yellow River estuary ecosystem was at an early development stage with higher vulnerability. The energy conversion efficiency of system was from 7.3% to 11.5%, the mean trophic levels of the catch were 3.23, 2.97 and 2.82 in

  19. Seasonal variation of nonylphenol concentrations and fluxes with influence of flooding in the Daliao River Estuary, China.

    PubMed

    Li, Zhengyan; Gibson, Mark; Liu, Chang; Hu, Hong

    2013-06-01

    Nonylphenol is an endocrine disruptor with harmful effects including feminization and carcinogenesis on various organisms. This study aims to investigate the distribution and ecological risks of nonylphenol in the Daliao River Estuary, China. Nonylphenol, together with other phenolic endocrine disruptors (bisphenol A, 4-t-butylphenol, 4-t-octylphenol, and 2,4-dichlorophenol), was detected in surface water and sediment on three cruises in May 2009, June 2010, and August 2010, respectively. A large flooding occurred during our sampling campaign in August and its effect on nonylphenol concentrations and fluxes in the estuary was therefore evaluated. The results showed that nonylphenol with a concentration range between 83.6-777 ng l(-1) and 1.5-456 ng g(-1) dw in surface water and sediment was the most abundant among the phenolic compounds, accounting for 59.1-81.0 and 79.9-92.1 % of the total phenolic concentration in surface water and sediment, respectively. The concentrations recorded in May and June were comparable, whereas those in August were considerably higher, mainly due to the flush of flooding. The flooding also caused a 50 times increase in nonylphenol flux from the estuary into the adjacent Bohai Sea. Nonylphenol concentrations in the estuary have exceeded the threshold level of undesirable effects with a potential risk of harm to local species, especially benthic organisms.

  20. Four arguments why so many alien species settle into estuaries, with special reference to the German river Elbe

    NASA Astrophysics Data System (ADS)

    Nehring, Stefan

    2006-05-01

    In one of the largest European rivers, the Elbe, from its source in the Czech Republic to the German North Sea, 31 alien macrozoobenthic species have been recorded in total. Most of these species have been introduced by shipping activities. With a total number of 21 species, many of the established aliens occur—partly exclusively—in the brackish area of the Elbe estuary. In order to explain this observed settlement characteristic, four main arguments come into consideration: (1) estuaries with intensive international shipping have a higher potential infection rate than other aquatic zones; (2) brackish water species have, due to specific physiological characteristics, a better chance of being transported alive than euhaline or freshwater species and they also probably have a higher perennation and establishment potential after release; (3) brackish waters have the greatest natural ‘indigenous species minimum’, so that more alien species can potentially establish; and (4) salt-tolerant limnetic alien species introduced into inland water reached the coast at first in the estuaries. It seems that the combination of brackish water with its unsaturated ecological niches and intensive international ship traffic has the highest potential infection rate for aquatic systems with alien macrozoobenthic species. And, estuaries are subjected to a two-sided invasion pressure by alien species, via the ocean (mainly shipping) and via inland waters (mainly shipping canal construction). The identification of such patterns is an important prerequisite for the development of a forward-looking alien monitoring and management strategy.

  1. Fish assemblage structure in the hypoxic zone in the Changjiang (Yangtze River) estuary and its adjacent waters

    NASA Astrophysics Data System (ADS)

    Shan, Xiujuan; Jin, Xianshi; Yuan, Wei

    2010-05-01

    Fish assemblage structure in the hypoxic zone in the Changjiang (Yangtze River) estuary and its adjacent waters were analyzed based on data from bottom trawl surveys conducted on the R/V Beidou in June, August and October 2006. Four fish assemblages were identified in each survey using two-way indicator species analysis (TWIA). High fish biomass was found in the northern part, central part and coastal waters of the survey area; in contrast, high fish diversity was found in the southern part of the survey area and the Changjiang estuary outer waters. Therefore, it is difficult to maintain high fishery production when high fish diversity is evenly distributed in the fish community. Fish became smaller and fish size spectra tended to be narrower because of fish species variations and differences in growth characteristics. Fish diversity increased, the age to maturity was reduced and some migrant species were not collected in the surveys. Fish with low economic value, small size, simple age structure and low tropic level were predominant in fish assemblages in the Changjiang estuary and its adjacent waters. The lowest hypoxic value decreased in the Changjiang estuary and its adjacent waters.

  2. A sensitivity analysis of low salinity habitats simulated by a hydrodynamic model in the Manatee River estuary in Florida, USA

    NASA Astrophysics Data System (ADS)

    Chen, XinJian

    2012-06-01

    This paper presents a sensitivity study of simulated availability of low salinity habitats by a hydrodynamic model for the Manatee River estuary located in the southwest portion of the Florida peninsula. The purpose of the modeling study was to establish a regulatory minimum freshwater flow rate required to prevent the estuarine ecosystem from significant harm. The model used in the study was a multi-block model that dynamically couples a three-dimensional (3D) hydrodynamic model with a laterally averaged (2DV) hydrodynamic model. The model was calibrated and verified against measured real-time data of surface elevation and salinity at five stations during March 2005-July 2006. The calibrated model was then used to conduct a series of scenario runs to investigate effects of the flow reduction on salinity distributions in the Manatee River estuary. Based on simulated salinity distribution in the estuary, water volumes, bottom areas and shoreline lengths for salinity less than certain predefined values were calculated and analyzed to help establish the minimum freshwater flow rate for the estuarine system. The sensitivity analysis conducted during the modeling study for the Manatee River estuary examined effects of the bottom roughness, ambient vertical eddy viscosity/diffusivity, horizontal eddy viscosity/diffusivity, and ungauged flow on the model results and identified the relative importance of these model parameters (input data) to the outcome of the availability of low salinity habitats. It is found that the ambient vertical eddy viscosity/diffusivity is the most influential factor controlling the model outcome, while the horizontal eddy viscosity/diffusivity is the least influential one.

  3. 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.

  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. 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.

  6. [Distribution of phosphorus in surface sediments from the Yellow River estuary wetland].

    PubMed

    Yu, Zi-Yang; Du, Jun-Tao; Yao, Qing-Zhen; Chen, Hong-Tao; Yu, Zhi-Gang

    2014-03-01

    Surface sediments were collected from Yellow River estuary wetland. The distribution of phosphorus in sediments was analyzed with modified SEDEX. The results indicated that the contents of TP in surface sediments varied from 12.12 micromol x g(-1) to 25.37 micromol x g(-1), and the mean value was 20.70 micromol x g(-1), in which the Detrital P and Authigenic P were the main forms. Median particle size was closely related with the distribution of phosphors, Exchangeable P, Authigenic P and Organic P mainly consisted of smaller sediment size, while Detrital P mainly consisted of larger sediment size. The distribution of P in sediment was affected by organic matter. Exchangeable P, organic P and refractory P increased with the increasing TOC. The bio-available phosphorus included exchangeable P, iron-bound P,organic P and ranged from 1.15-6.74 micromol x g(-1), with an average of 4.27 micromol x g(-1) for all sediment samples. The contribution of BAP to TP was 6.35% -30.4%.

  7. [Health assessment of Qi'ao Island mangrove wetland ecosystem in Pearl River Estuary].

    PubMed

    Wang, Shu-Gong; Zheng, Yao-Hui; Peng, Yi-Sheng; Chen, Gui-Zhu

    2010-02-01

    Based on the theories of wetland ecosystem health and by using "Pressure-State-Response" model, a health assessment indicator system for Qi' ao Island mangrove wetland ecosystem in Pearl River Estuary was built, and the assessment indices, assessment criteria, indices weighted values, assessment grades, and assessment methods were established to assess the health state of this ecosystem. In 2008, the overall health index of this ecosystem was 0.6580, health level was of grade II (healthy), and the pressure, state, and response indices were 0.3469, 0.8718, and 0.7754, respectively, suggesting that this ecosystem was good in state and response, but still had definite pressure. As a provincial nature reserve, this ecosystem was to be further improved in its health level. However, the research on the health assessment of mangrove wetland ecosystem was still young. Further studies should be made on the selection of assessment indices, long-term oriented monitoring of these indices, and quantification of the relations between ecosystem health level and ecosystem services.

  8. Legacy and emerging halogenated organic pollutants in marine organisms from the Pearl River Estuary, South China.

    PubMed

    Sun, Run-Xia; Luo, Xiao-Jun; Tan, Xiao-Xin; Tang, Bin; Li, Zong-Rui; Mai, Bi-Xian

    2015-11-01

    A suite of legacy and emerging halogenated organic pollutants (HOPs) were measured in marine organisms (coastal fish and invertebrates) from the Pearl River Estuary, South China, to investigate the current contamination status after the Stockholm Convention was implemented in China. Dichlorodiphenyltrichloroethane and its metabolites (DDTs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) were detected in all samples at concentrations of 54-1500, 16-700, and 0.56-59ng/g lipid weight, respectively. Dechlorane Plus (DP), decabromodiphenyl ethane (DBDPE), 2,3,5,6-tetrabromo-p-xylene (pTBX), and pentabromotoluene (PBT) were also found at concentrations of ND (non-detectable) to 37ng/g lipid weight. The concentrations of these investigated contaminants in the present study were at moderate levels, as compared with those reported in other regions. Significant interspecies differences were found in the levels of DDTs, PCBs, PBDEs and the alternative halogenated flame retardants (AHFRs). DDTs were the predominant HOPs in those species and represented >50% of the total HOPs, followed by PCBs, PBDEs, and AHFRs. The total estimated daily intakes (EDIs) of DDTs, PCBs, PBDEs, and AHFRs were 28, 12, 1.0, and 0.18 (ng/kg)/d, respectively, via seafood consumption. These concentrations are not expected to pose health risks to humans. PMID:26318119

  9. 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.

  10. Ecological patterns of the rotifer communities in the Kaw River estuary (French Guiana)

    NASA Astrophysics Data System (ADS)

    Rougier, C.; Pourriot, R.; Lam-Hoai, T.; Guiral, D.

    2005-04-01

    A study of the rotifer fauna in the Kaw River estuary revealed significant quantitative and qualitative variations as a function of precipitation pattern and resulting hydrology and hydrochemistry. The rainy season (flood period) was characterized by the presence of about one hundred rotifer species of the periphytic continental type, each present at a very low average density (8 to 10 ind l -1). Rotifers generally constituted the majority of the zooplankton (above 70%). The dry season (low water period) was characterized by a small number (four) of species of the 'marine coastal' plankton type, showed the highest density peaks (>500 ind l -1). While the fluvial hydrodynamics during the rainy season contributed to a complete mixing of populations across the estuarine zone, the oceanic hydrodynamics during the dry season led to great population instability at the station level. At an annual scale, this estuarine zone is thus an essentially open environment that lacks a clearly-structured rotifer population, and which therefore most likely does not constitute a distinct, internally-functioning ecosystem.

  11. 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.

  12. Dissolved Fe(II) in a river-estuary system rich in dissolved organic matter

    NASA Astrophysics Data System (ADS)

    Hopwood, Mark J.; Statham, Peter J.; Milani, Ambra

    2014-12-01

    Reduced iron, Fe(II), accounts for a significant fraction of dissolved Fe across many natural surface waters despite its rapid oxidation under oxic conditions. Here we investigate the temporal and spatial variation in dissolved Fe redox state in a high dissolved organic matter (DOM) estuarine system, the River Beaulieu. We couple manual sample collection with the deployment of an autonomous in situ analyser, designed to simultaneously measure dissolved Fe(II) and total dissolved Fe, in order to investigate processes operating on the diurnal timescale and to evaluate the performance of the analyser in a high DOM environment. Concentrations of dissolved Fe available to the ligand ferrozine are elevated throughout the estuary (up to 21 μM in freshwater) and notably higher than those previously reported likely due to seasonal variation. Fe(II) is observed to account for a large, varying fraction of the dissolved Fe available to ferrozine (25.5 ± 12.5%) and this fraction decreases with increasing salinity. We demonstrate that the very high DOM concentration in this environment and association of this DOM with dissolved Fe, prevents the accurate measurement of dissolved Fe concentrations in situ using a sensor reliant on rapid competitive ligand exchange.

  13. [Seasonal dynamics of nitrogen- and phosphorus absorption efficiency of wetland plants in Minjiang River estuary].

    PubMed

    Zhang, Wen-Long; Zeng, Cong-Sheng; Zhang, Lin-Hai; Wang, Wei-Qi; Lin, Yan; Ai, Jin-Quan

    2009-06-01

    Taking the native Phragmites australis and invasive Spartina alterniflora in Minjiang River estuary as test objectives, this paper studied the seasonal dynamics of their biomass and nitrogen- and phosphorus absorption efficiency. A typical single-peak curve was presented for the seasonal dynamics of aboveground biomass and nitrogen- and phosphorus absorption efficiency of the two species. P. australis had the maximum aboveground biomass (2195.33 g X m(-2)) in summer, while S. alterniflora had it (3670.02 g X m(-2)) in autumn. The total nitrogen (TN) and total phosphorus (TP) contents of P. australis reached the peak (21.06 g x m(-2) of TN and 1.12 g x m(-2) of TP) in summer and in autumn, respectively, while those of S. alterniflora all reached the peak (26.76 g x m(-2) of TN and 3.23 g x m(-2) of TP) in autumn. Both of the two species had a higher absorption efficiency in TN than in TP (P < 0.01), and S. alterniflora had a significantly higher absorption efficiency of TN and TP than P. australis (P < 0.05). To some extent, the N/P, C/N, and C/P ratios of plants could indicate the nitrogen- and phosphorus absorption efficiency of the plants.

  14. Influence of climate factors on Vibrio cholerae dynamics in the Pearl River estuary, South China.

    PubMed

    Yue, Yujuan; Gong, Jianhua; Wang, Duochun; Kan, Biao; Li, Baisheng; Ke, Changwen

    2014-06-01

    Current research has seldom focused on the quantitative relationships between Vibrio cholerae (V. cholerae) and climate factors owing to the complexities and high cost of field observation in the aquatic environment. This study has focused on the relationships between V. cholerae and climate factors based on linear regression method and data partition method. Data gathered from 2008 to 2009 in the Pearl River estuary, South China, were adopted. Positive rate of V. cholerae was correlated closely with monthly climate factors of water temperature and air temperature, respectively in 2009. Quarterly data analysis from 2008 to 2009 showed that there existed seasonal characteristic for V. cholerae. Positive rate of V. cholerae was correlated positively with quarterly climate factors of land surface temperature, pH, water temperature, air temperature and rainfall, respectively and negatively with quarterly air pressure. Partition data analysis in 2009 showed that there existed geography region characteristic for V. cholerae. V. cholerae dynamics was closely correlated to climate factors in the downstream area. However, it was more greatly affected by human geography factors in the urban area. Positive annual rate of V. cholerae was higher in the downstream area than in the urban area both in 2008 and 2009. At last, a cellular automaton model was used to simulate V. cholerae diffusion downstream, and the distribution of V. cholerae obtained from this model was similar to that obtained from the field observations.

  15. Legacy and emerging halogenated organic pollutants in marine organisms from the Pearl River Estuary, South China.

    PubMed

    Sun, Run-Xia; Luo, Xiao-Jun; Tan, Xiao-Xin; Tang, Bin; Li, Zong-Rui; Mai, Bi-Xian

    2015-11-01

    A suite of legacy and emerging halogenated organic pollutants (HOPs) were measured in marine organisms (coastal fish and invertebrates) from the Pearl River Estuary, South China, to investigate the current contamination status after the Stockholm Convention was implemented in China. Dichlorodiphenyltrichloroethane and its metabolites (DDTs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) were detected in all samples at concentrations of 54-1500, 16-700, and 0.56-59ng/g lipid weight, respectively. Dechlorane Plus (DP), decabromodiphenyl ethane (DBDPE), 2,3,5,6-tetrabromo-p-xylene (pTBX), and pentabromotoluene (PBT) were also found at concentrations of ND (non-detectable) to 37ng/g lipid weight. The concentrations of these investigated contaminants in the present study were at moderate levels, as compared with those reported in other regions. Significant interspecies differences were found in the levels of DDTs, PCBs, PBDEs and the alternative halogenated flame retardants (AHFRs). DDTs were the predominant HOPs in those species and represented >50% of the total HOPs, followed by PCBs, PBDEs, and AHFRs. The total estimated daily intakes (EDIs) of DDTs, PCBs, PBDEs, and AHFRs were 28, 12, 1.0, and 0.18 (ng/kg)/d, respectively, via seafood consumption. These concentrations are not expected to pose health risks to humans.

  16. 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

  17. [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.

  18. [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

  19. [Phytoplankton assemblage in Yangtze River estuary and its adjacent waters in winter time].

    PubMed

    He, Qing; Sun, Jun; Luan, Qing-shan; Song, Shu-qun; Shen, Zhi-liang; Wang, Dan

    2007-11-01

    Water samples were collected from Yangtze River Estuary and its adjacent waters in 28th February-10th March, 2005, and the species composition of phytoplankton was analyzed by Utermöhl method. A total of 130 taxa (including 25 uncertain species) which belong to 67 genera of 5 phyla were identified. The phytoplankton community was mainly composed of Bacillariophyta, followed by Dinophyta. There were also a few species belonging to Chrysophyceae, Cyanophyceae and Chlorophyceae. The dominant species were Paralia sulcata, Skeletonema costatum, Thalassiosira rotula, Bleakeleya notata, Coscinodiscus radiatus and Thalassiosira excentrica. The cell abundance of phytoplankton ranged from 0.1 to 90.0 cells x ml(-1), with an average of 10.1 cells x ml(-1). Horizontally, the cell abundance was relatively high in inshore and low in offshore; while vertically, it was high in surface water and decreased slightly with increasing water depth. The cell abundance and chl a concentration of phytoplankton positively correlated with the concentrations of nitrate, nitrite, ammonium, phosphate and silicate in water, but negatively correlated with water salinity. The Shannon-Wiener diversity index and Pielou evenness index were higher in the center of survey area but lower in northeast part and inshore area.

  20. Tidally averaged water and salt transport velocities and their distributions in the Pearl River Estuary

    NASA Astrophysics Data System (ADS)

    Zhu, Shouxian; Sheng, Jinyu; Ji, Xiaomei

    2016-09-01

    Tidally averaged transports of water and substance are important physical quantities over estuarine, coastal, and shelf waters, but they have been indistinguishably expressed in terms of the Eulerian residual current (ERC) or Lagrangian residual current (LRC) in many previous studies. In this study, the tidally averaged transport velocities for water (TA-WTV) and substance (TA-STV) are considered based on residual fluxes. The main advantage of these newly defined transport velocities is that they can be used to quantify differences in amplitude and direction between the tidally averaged water and substance transports. The two-dimensional TA-STV is interpreted as the transport due to the residual flow of water, tidal pumping, and vertical shear. The three-dimensional TA-STV includes transports from the residual flow of water and tidal pumping. Numerical results of sea surface elevations, currents, and salinity produced by a triply nested coastal ocean model for the Pearl River Estuary (PRE) are used to calculate the TA-WTV and TA-STV for salt (TA-STVsa). The general features of the TA-WTV and TA-STVsa are similar over the most part of the PRE but differ significantly in amplitude and direction over the salinity frontal zone. The ERC and LRC calculated from model results are also significantly different from the TA-STVsa over the salinity frontal zone.

  1. 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.

  2. 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.

  3. 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.

  4. Remotely sensed assessment of water quality levels in the Pearl River Estuary, China.

    PubMed

    Chen, Chuqun; Tang, Shiling; Pan, Zhilin; Zhan, Haigang; Larson, Magnus; Jönsson, Lennart

    2007-08-01

    In this paper, a method of assessing water quality from satellite data is introduced. The composite pollution index (CPI) was calculated from measured chemical oxygen demand (COD) and nutrient concentration. The relationships between CPI and 240 band combinations of SeaWiFS water-leaving radiance were analyzed and the optimal band combination for estimating CPI was chosen from the 240 band combinations. An algorithm for retrieval of CPI was developed using the optimal band combination, (L(443)xL(510))/(L(412)+L(490)). The CPI was estimated from atmospherically corrected SeaWiFS data by employing the algorithm. Furthermore, the CPI value range for each water quality level was determined based on data obtained from 850 samples taken in the Pearl River Estuary. The remotely sensed CPIs were then transferred to water quality levels and appropriate maps were derived. The remotely sensed water quality level maps displayed a similar distribution of levels based on in situ investigation issued by the State Ocean Administration, China. This study demonstrates that remote sensing can play an important role in water quality assessment.

  5. Mercury distribution, speciation and bioavailability in sediments from the Pearl River Estuary, Southern China.

    PubMed

    Yu, Xiujuan; Li, Hengxiang; Pan, Ke; Yan, Yan; Wang, Wen-Xiong

    2012-08-01

    Surface sediments and sediment cores collected from the Pearl River Estuary (PRE) were analyzed for total mercury (THg) concentrations and speciation using a sequential extraction method. The mobility of Hg in sediments was also assessed using a series of single extraction methods. The surface sediments from the PRE showed slightly elevated levels of Hg, with concentrations ranging from 109 to 453 ng/g. The vertical profile of THg in sediment cores indicated an accelerated input of Hg over the past decades. The organo-chelated and strong-complexed Hg species were the dominant Hg species in the sediments, while the more mobile phases of Hg made up less than 0.5% of THg. Less than 10% of the Hg in the sediments was extracted by single extraction, depending on the extractant employed. Significant relationships were found between the total organic carbon and THg, geochemical speciation, and extractability, indicating the important role of organic matter in controlling the distribution, mobility, and bioavailability of Hg in sediments.

  6. 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.

  7. [Changes of wetland landscape pattern in Dayang River Estuary based on high-resolution remote sensing image].

    PubMed

    Wu, Tao; Zhao, Dong-zhi; Zhang, Feng-shou; Wei, Bao-quan

    2011-07-01

    Based on the comprehensive consideration of the high resolution characteristics of remote sensing data and the current situation of land cover and land use in Dayang River Estuary wetland, a classification system with different resolutions of wetland landscape in the Estuary was established. The landscape pattern indices and landscape transition matrix were calculated by using the high resolution remote sensing data, and the dynamic changes of the landscape pattern from 1984 to 2008 were analyzed. In the study period, the wetland landscape components changed drastically. Wetland landscape transferred from natural wetland into artificial wetland, and wetland core regional area decreased. Natural wetland's largest patch area index descended, and the fragmentation degree ascended; while artificial wetland area expanded, its patch number decreased, polymerization degree increased, and the maximum patch area index had an obvious increasing trend. Increasing human activities, embankment construction, and reclamation for aquaculture were the main causes for the decrease of wetland area and the degradation of the ecological functions of Dayang River Estuary. To constitute long-term scientific and reasonable development plan, establish wetland nature reserves, protect riverway, draft strict inspective regimes for aquaculture reclamation, and energetically develop resource-based tourism industry would be the main strategies for the protection of the estuarine wetland. PMID:22007462

  8. [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.

  9. Anthropogenic effects on greenhouse gas (CH4 and N2O) emissions in the Guadalete River Estuary (SW Spain).

    PubMed

    Burgos, M; Sierra, A; Ortega, T; Forja, J M

    2015-01-15

    Coastal areas are subject to a great anthropogenic pressure because more than half of the world's population lives in its vicinity causing organic matter inputs, which intensifies greenhouse gas emissions into the atmosphere. Dissolved concentrations of CH4 and N2O have been measured seasonally during 2013 in the Guadalete River Estuary, which flows into the Cadiz Bay (southwestern Spanish coast). It has been intensely contaminated since 1970. Currently it receives wastewater effluents from cities and direct discharges from nearby agriculture crop. Eight sampling stations have been established along 18 km of the estuary. CH4 and N2O were measured using a gas chromatograph connected to an equilibration system. Additional parameters such as organic matter, dissolved oxygen, nutrients and chlorophyll were determinate as well, in order to understand the relationship between physicochemical and biological processes. Gas concentrations increased from the River mouth toward the inner part, closer to the wastewater treatment plant discharge. Values varied widely within 21.8 and 3483.4 nM for CH4 and between 9.7 and 147.6 nM for N2O. Greenhouse gas seasonal variations were large influenced by the precipitation regime, masking the temperature influence. The Guadatete Estuary acted as a greenhouse gas source along the year, with mean fluxes of 495.7 μmol m(-2)d(-1) and 92.8 μmol m(-2)d(-1) for CH4 and N2O, respectively.

  10. [Changes of wetland landscape pattern in Dayang River Estuary based on high-resolution remote sensing image].

    PubMed

    Wu, Tao; Zhao, Dong-zhi; Zhang, Feng-shou; Wei, Bao-quan

    2011-07-01

    Based on the comprehensive consideration of the high resolution characteristics of remote sensing data and the current situation of land cover and land use in Dayang River Estuary wetland, a classification system with different resolutions of wetland landscape in the Estuary was established. The landscape pattern indices and landscape transition matrix were calculated by using the high resolution remote sensing data, and the dynamic changes of the landscape pattern from 1984 to 2008 were analyzed. In the study period, the wetland landscape components changed drastically. Wetland landscape transferred from natural wetland into artificial wetland, and wetland core regional area decreased. Natural wetland's largest patch area index descended, and the fragmentation degree ascended; while artificial wetland area expanded, its patch number decreased, polymerization degree increased, and the maximum patch area index had an obvious increasing trend. Increasing human activities, embankment construction, and reclamation for aquaculture were the main causes for the decrease of wetland area and the degradation of the ecological functions of Dayang River Estuary. To constitute long-term scientific and reasonable development plan, establish wetland nature reserves, protect riverway, draft strict inspective regimes for aquaculture reclamation, and energetically develop resource-based tourism industry would be the main strategies for the protection of the estuarine wetland.

  11. 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.

  12. Speciation of selected heavy metals geochemistry in surface sediments from Tirumalairajan river estuary, east coast of India.

    PubMed

    Venkatramanan, S; Ramkumar, T; Anithamary, I; Jonathan, M P

    2013-08-01

    Surface sediment samples from the Tirumalairajan river estuary were studied for grain size pattern, organic matter, and heavy metals (Fe, Mn, Zn, and Pb) using the sequential and bulk metal extraction methods to evaluate metal behavior. Ten surface sediment samples were collected during the monsoon and summer seasons of the year 2009. The observed orders of concentrations of heavy metals in the sediments were as follows: Fe > Mn > Zn > Pb. The results obtained from sequential extraction showed that, among the metals studied, a larger portion of the metals were associated with the residual phase, although they are available in other fractions. The low concentration of metals available in bioavailable phases indicated that the sediments of Tirumalairajan river estuary were relatively unpolluted. Correlation analysis was also carried out to understand the associations of metals in different phases with sand, silt, clay, and organic matter. To understand the risk of heavy metals to sediment-dwelling organisms, the data were compared with risk assessment code and sediment quality values using the screening quick reference table. The main source of metals to the estuary is from the irrigation field and its associated activities in the study area.

  13. 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

  14. 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...

  15. [Distribution and source of particulate organic carbon and particulate nitrogen in the Yangtze River Estuary in summer 2012].

    PubMed

    Xing, Jian-Wei; Xian, Wei-Wei; Sheng, Xiu-Zhen

    2014-07-01

    Based on the data from the cruise carried out in August 2012 in the Yangtze River Estuary and its adjacent waters, spatial distributions of particulate organic carbon (POC), particulate nitrogen (PN) and their relationships with environmental factors were studied, and the source of POC and the contribution of phytoplankton to POC were analyzed combined with n (C)/n (N) ratio and chlorophyll a (Chl a) in the Yangtze River Estuary in summer 2012. The results showed that the concentrations of POC in the Yangtze River Estuary ranged from 0.68 mg x L(-1) to 34.80 mg x L(-1) in summer and the average content was 3.74 mg x L(-1), and PN contents varied between 0.03 mg x L(-1) and 9.13 mg x L(-1) with an average value of 0.57 mg x L(-1). Both of them presented that the concentrations in bottom layers were higher than those in the surface. POC and PN as well as total suspended matter (TSM) showed a extremel similar horizontal distribution trend that the highest values appeared in the near of the mouth and southwest of the survey waters, and decreased rapidly as toward the open seas, both of them showed higher contents in coastal zones and lower in outer sea. There was a fairly good positive linear relationship between POC and PN, which indicated that they had the same source. POC and PN expressed significantly positive correlations with TSM and chemical oxygen demand (COD), but showed relatively weak correlations with salinit and chlorophyll a, which demonstrated that terrestrial inputs had a strong influence on the distribution of POC and PN, and phytoplankton production was not the major source of organic matters in the Yangtze River Estuary. Both the n (C)/n (N) ratio and POC/Chl a analysis showed that the main source of POC was terrestrial inputs, and organic debris was the main existence form of POC. Quantitative analysis showed the biomass of phytoplankton only made an average of 2.54% contribution to POC in the Yangtze Rive Estuary in summer and non-living POC

  16. 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.

  17. 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

  18. 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

  19. Occurrence, distribution, and sources of six phenolic endocrine disrupting chemicals in the 22 river estuaries around Dianchi Lake in China.

    PubMed

    Wang, Bin; Huang, Bin; Jin, Wei; Zhao, Shimin; Li, Farong; Hu, Ping; Pan, Xuejun

    2013-05-01

    The objectives of this study are to track the occurrence, distribution, and sources of phenolic endocrine disrupting compounds (EDCs) in the 22 rivers around Dianchi Lake in China, to estimate the input and output amounts of phenolic EDCs in the water system, and to provide more comprehensive fundamental data for risk assessment and contamination control of phenolic EDCs in aquatic environment. Six phenolic EDCs were systematically evaluated in water and surface sediment in the estuaries of those rivers. The water and sediment samples were preconcentrated by solid-phase extraction system and microwave-assisted extraction system, respectively. Phenolic EDCs were analyzed by GC-MS (Thermo Fisher Scientific, USA) after derivatization. Phenolic EDCs were found ubiquitously in the aquatic environment. The total concentrations ranged from 248 to 4,650 ng/L in water, and 113 to 3,576 ng/g dry weight in surface sediment. The residue amount of phenolic EDCs in Dianchi Lake was 258 kg/a. Concentrations of the phenolic EDCs in the Lake decreased with increase in distance to the estuaries of those rivers which run through urban and industrial areas. The rivers seriously contaminated by phenolic EDCs were Xin River, Yunliang River, Chuanfang River, Cailian River, Jinjia River, Zhengda River, and Daqing River which run through the old area of Kunming City. Satisfying correlations were observed between the concentrations of the target compounds in water and in surface sediment. NP1EO, NP2EO, and BPA were identified as the three predominant phenolic EDCs. There were significant correlations between phenolic EDCs and many basic water quality parameters. Urban and industrial areas are the major contributors for phenolic EDCs, especially in Kunming City. Compositional profiles of phenolic EDCs in surface sediment were similar to those in river water. The concentrations of phenolic EDCs in the rivers located in the northwest part of the valley were very high, and posed a potential

  20. 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

  1. 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

  2. Bayesian networks for environmental flow decision-making and an application in the Yellow River estuary, China

    NASA Astrophysics Data System (ADS)

    Pang, A. P.; Sun, T.

    2014-05-01

    We proposed an approach for environmental flow decision-making based on Bayesian networks considering seasonal water use conflicts between agriculture and ecosystems. Three steps were included in the approach: water shortage assessment after environmental flow allocation using a production-loss model considering temporal variations of river flows; trade-off analysis of water use outcomes by Bayesian networks; and environmental flow decision-making based on a risk assessment under different management strategies. An agricultural water shortage model and a production-loss model were integrated after satisfying environmental flows with temporal variability. The case study in the Yellow River estuary indicated that the average difference of acceptable economic loss for winter wheat irrigation stakeholders was 10% between water saving measures and water diversion projects. The combination of water diversion projects and water-saving measures would allow 4.1% more river inflow to be allocated to ecological needs in normal years without further economic losses in agriculture.

  3. Vegetation of the Elwha River estuary: Chapter 8 in Coastal habitats of the Elwha River, Washington--biological and physical patterns and processes prior to dam removal

    USGS Publications Warehouse

    Shafroth, Patrick B.; Fuentes, Tracy L.; Pritekel, Cynthia; Beirne, Matthew M.; Beauchamp, Vanessa B.; Duda, Jeffrey J.; Warrick, Jonathan A.; Magirl, Christopher S.

    2011-01-01

    The Elwha River estuary supports one of the most diverse coastal wetland complexes yet described in the Salish Sea region, in terms of vegetation types and plant species richness. Using a combination of aerial imagery and vegetation plot sampling, we identified 6 primary vegetation types and 121 plant species in a 39.7 ha area. Most of the estuary is dominated by woody vegetation types, with mixed riparian forest being the most abundant (20 ha), followed by riparian shrub (6.3 ha) and willow-alder forest (3.9 ha). The shrub-emergent marsh transition vegetation type was fourth most abundant (2.2 ha), followed by minor amounts of dunegrass (1.75 ha) and emergent marsh (0.2 ha). This chapter documents the abundance, distribution, and floristics of these six vegetation types, including plant species richness, life form, species origin (native or introduced), and species wetland indicator status. These data will serve as a baseline to which future changes can be compared, following the impending removal of Glines Canyon and Elwha Dams upstream on the Elwha River. Dam removals may alter many of the processes, materials, and biotic interactions that influence the estuary plant communities, including hydrology, salinity, sediment and wood transport, nutrients, and plant-microbe interactions.

  4. 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

  5. Spatial distribution and feeding of dominant zooplankton species in the Ob River estuary

    NASA Astrophysics Data System (ADS)

    Drits, A. V.; Nikishina, A. B.; Semenova, T. N.; Sergeeva, V. M.; Solovyev, K. A.; Flint, M. V.

    2016-05-01

    The distribution and feeding of dominant mesozooplankton species were studied in the estuary of the Ob River and adjacent inner Kara Sea shelf waters in September 2013. It was shown that the spatial distributions of Cyclops sp., Senecella siberica, Limnocalanus macrurus, Mysis oculata, Drepanopus bungei, Jashnovia tolli and Pseudocalanus sp. are related to the specific characteristics of the hydrographic regime in the estuarine frontal zone. The distributions of Cyclops sp., Senecella siberica, and Pseudocalanus sp. are mainly limited by salinity, while other species inhabit an area with a wide range of salinity values without clear preferences. Peaks of their abundance could be either consolidated or distanced in space. The populations of Jashnovia tolli, Drepanopus bungei, and Pseudocalanus sp. permanently inhabit the layer under the pycnohalocline; the populations of Cyclops sp. and Mysis oculata inhabit the upper mixed layer. Limnocalanus macrurus demonstrates a different vertical distribution pattern: the copepod undertakes diel vertical migrations in the southern part of the estuarine frontal zone; in its northern part, the population is concentrated below the pycnocline during day and night. The differences in the distributions of the studied species determine their feeding behavior and their role in phytoplankton grazing. The most intense utilization of biomass and production of autotrophic phytoplankton by zooplankton occur in the freshened water zone and the adjacent southern periphery of the estuarine frontal zone: the total daily phytoplankton consumption makes up 10-18% of the biomass and 60-380% of primary production. Daily zooplankton consumption of phytoplankton in the estuarine frontal zone decreases to 2-7% of the biomass and to 14% of primary production; in inner shelf waters, the values do not exceed 1% for both phytoplankton biomass and production.

  6. [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.

  7. 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.

  8. Waterbird population changes in the wetlands at Chongming Dongtan in the Yangtze River estuary, China.

    PubMed

    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.

  9. 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.

  10. 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

  11. Modelling Kepone in the striped bass food chain of the James River estuary

    NASA Astrophysics Data System (ADS)

    Connolly, John P.; Tonelli, Rosella

    1985-03-01

    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 concentrations and then to address the question of why these levels still exceed Food and Drug Administration limits eight years after discharge ceased. The model considers exposure through diet and respiration at rates based on species bioenergetics. It was successfully calibrated to the Kepone concentrations observed in the period 1976 through 1982 in striped bass, white perch, and Atlantic croaker. The model indicates that for the upper levels of the food chain, diet is the major route of contamination, accounting for 87-88% of the observed concentration in croaker and white perch and 91% of the observed concentration in striped bass. The two Kepone sources; sediment and water column, contribute approximately equally to the croaker and white perch. The water column is more significant for striped bass, being the original source for approximately 60% of the observed body burdens. It was estimated that a criterion requiring Kepone concentrations in fish to be at or below 0·3 μg g -1 would require dissolved water column and sediment Kepone concentrations to be reduced to somewhere between 3 and 9 ng l -1 and 13-39 ng g -1, respectively, depending on the species. Striped bass require the greatest reductions in dissolved water column and sediment Kepone concentrations to somewhere between 3 and 5 ng l -1 and 13 and 24 ng g -1, respectively.

  12. Microphytobenthic biomass and species composition in intertidal flats of the Nakdong River estuary, Korea

    NASA Astrophysics Data System (ADS)

    Du, GuoYing; Son, Moonho; Yun, Misun; An, Soonmo; Chung, Ik Kyo

    2009-05-01

    Intertidal microphytobenthos (MPB) were investigated monthly from August 2006 to March 2008 at four different sites in the sand flats of Nakdong River estuary, Korea. Samples of surface sediment (ca. 1 cm) were collected, and chlorophyll a was extracted as biomass estimation. Species identification and enumeration were carried out by light microscopy, assisted where necessary by scanning electronic microscopy. Biomass varied between 0.47 and 16.58 μg cm -3, abundance changed from 5.25 to 414.75 × 10 3 cells cm -3, while the Shannon diversity indexes ranged between 0.69 and 2.35 H'. Thirty-nine MPB taxa were identified, primarily composed of epipelic diatoms, among which Amphora and Navicula were the most abundant genera. Based on the biomass, abundance, species composition and their dynamics, MPB assemblages of sampling sites were grouped into three distinct communities corresponding to their sediment composition characteristics. Multivariate correlation analysis revealed that biomass was positively related to mud and very fine sand, negatively related to fine and medium sand, but not significantly related to environmental factors such as pore water nutrients, light intensity and salinity, which fluctuated rapidly during emersion period. Cluster analysis corroborated the division of MPB communities according to site types on seasonal scales, and also showed seasonality between sites by cluster of all summer groups. Principal component analysis identified that variability in species composition was significantly affected by mud, very fine sand, fine sand, light intensity, and sediment temperature. This study suggests that sediment composition plays an important role in the functioning of intertidal MPB communities in estuarine ecosystems.

  13. [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

  14. 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.

  15. [Distribution characteristics of nitrogen and its source in core sediments from Pearl River Estuary].

    PubMed

    Yue, Wei-zhong; Huang, Xiao-ping

    2005-03-01

    Based on the measurement of the concentration of nitrogen in four core sediments from Pear River Estuary, the forms and the depth-dependent changes characteristics of nitrogen were studied, and the possible sources of nitrogen in the sediments were discussed. The results indicate that the content of total nitrogen ranged from 850.62mg/kg to 2 340.85mg/kg, with mean content of 1 502.73mg/kg. There is a general tendency for an upward increase in core sediments, which is more evident in the middle than in two ends. Organic nitrogen had a range of content from 655.42mg/kg to 2 029.86mg/kg, with mean content of 1 187.86mg/kg. And the content of organic nitrogen decreases gradually with the increase of depth or lower in the middle than in two ends. The content of NH4-N was relatively high, ranging from 47.59mg/kg to 739.61mg/kg, with mean content of 271.69mg/kg, and increases obviously with the increase of depth. The TOC/TN ratios were most between 5 and 17, which show organic matter is the mixture of aquatic and terrestrial sources. The total nitrogen has distinct synchronization phenomenon with the organic nitrogen in sedimentation course,but has little relativity with the NH4-N. There is large difference of synchronization phenomenon between total nitrogen and NH4-N at different sites.

  16. 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

  17. 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).

  18. 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

  19. 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

  20. Water quality of the tidal Potomac River and Estuary; hydrologic data report supplement, 1979 through 1981 water years

    USGS Publications Warehouse

    Coupe, R.H.; Webb, W.E.

    1984-01-01

    This report is a companion report to the U.S. Geological Survey 1979, 1980, and 1981 Hydrologic Data Reports of the tidal Potomac River and Estuary. It 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. (USGS)

  1. Phylogenetic analysis of particle-attached and free-living bacterial communities in the Columbia river, its estuary, and the adjacent coastal ocean.

    PubMed

    Crump, B C; Armbrust, E V; Baross, J A

    1999-07-01

    The Columbia River estuary is a dynamic system in which estuarine turbidity maxima trap and extend the residence time of particles and particle-attached bacteria over those of the water and free-living bacteria. Particle-attached bacteria dominate bacterial activity in the estuary and are an important part of the estuarine food web. PCR-amplified 16S rRNA genes from particle-attached and free-living bacteria in the Columbia River, its estuary, and the adjacent coastal ocean were cloned, and 239 partial sequences were determined. A wide diversity was observed at the species level within at least six different bacterial phyla, including most subphyla of the class Proteobacteria. In the estuary, most particle-attached bacterial clones (75%) were related to members of the genus Cytophaga or of the alpha, gamma, or delta subclass of the class Proteobacteria. These same clones, however, were rare in or absent from either the particle-attached or the free-living bacterial communities of the river and the coastal ocean. In contrast, about half (48%) of the free-living estuarine bacterial clones were similar to clones from the river or the coastal ocean. These free-living bacteria were related to groups of cosmopolitan freshwater bacteria (beta-proteobacteria, gram-positive bacteria, and Verrucomicrobium spp.) and groups of marine organisms (gram-positive bacteria and alpha-proteobacteria [SAR11 and Rhodobacter spp.]). These results suggest that rapidly growing particle-attached bacteria develop into a uniquely adapted estuarine community and that free-living estuarine bacteria are similar to members of the river and the coastal ocean microbial communities. The high degree of diversity in the estuary is the result of the mixing of bacterial communities from the river, estuary, and coastal ocean.

  2. The changes in trace metal contamination over the last decade in surface sediments of the Pearl River Estuary, South China.

    PubMed

    Chen, Baowei; Liang, Ximei; Xu, Weihai; Huang, Xiaoping; Li, Xiangdong

    2012-11-15

    Surface sediments can provide useful information on the recent pollution status of an estuary. One recent field survey was carried out in the Pearl River Estuary (PRE), South China in 2011. The comparisons with previous surveys demonstrated that the concentrations of Ni and Pb in the PRE declined over the last decade, but the concentration of Cu increased in the same time frame. The significant decreases in the concentrations of Ni and Pb were probably due to a reduction of anthropogenic inputs, such as industrial wastewater, into the PRE environment, and the ban imposed on leaded gasoline. Statistical analyses have consistently demonstrated that the process of the sedimentation of fine particles was the dominant factor in controlling the transport and distribution of trace metals in the PRE. The riverine trace metals generally displayed a pattern of diffusion from the northwest to the southeast in the estuary. However, the riparian industrial activities at the east bank of the inner PRE caused significant metal contamination in sediments. In general, effective pollution control measures in the PRD region have decreased the levels of some trace metals in the entire PRE over the last decade with the exception of Cu.

  3. 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...

  4. 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 ecosyst