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Sample records for river estuary southeastern

  1. Factors regulating community composition of methanogens and sulfate-reducing bacteria in brackish marsh sediments in the Min River estuary, southeastern China

    Science.gov (United States)

    She, C. X.; Zhang, Z. C.; Cadillo-Quiroz, H.; Tong, C.

    2016-11-01

    Assessing the diverse communities of methanogenic Archaea and sulfate-reducing bacteria (SRB) is important to understand methane (CH4) production in wetland ecosystems. However, the vertical distribution of composition and diversity, and the effects of environmental factors on the methanogen and SRB communities in the sediments of subtropical estuarine brackish marshes have been poorly characterized. To assess the effects of variable environmental conditions on methanogenic and SRB communities in marshes, we studied three brackish marsh zones dominated by Phragmites australis, Cyperus malaccensis and Spartina alterniflora, respectively, in the Min River estuary, southeastern China. Methanogens of the Methanomicrobiales order was the dominant group at sediment depths of 0-30 cm, which indicated that the main pathway of methane production was H2/CO2 in this zone. In general, methanogens of the genus Methanoregula were dominant in the three marsh zones. For SRB, Desulfobacterales was the dominant group, and Desulfobacterium and Desulfosarcina were the predominant genera at the depth of 0-30 cm. The community composition of methanogens and SRB changed with vegetation type and soil depth. Compared with SRB, vegetation type demonstrated a stronger influence on the community composition of methanogens. Canonical correspondence analysis (CCA) analysis further revealed that the main factors affecting the methanogens community composition were EC (electric conductivity) and pH, and the main factors affecting SRB community composition were pH, SOC and TN, suggesting that pH is a common factor influencing the community compositions of both methanogen and SRB in the sediments of brackish marshes.

  2. Nutrient concentrations and loads and Escherichia coli densities in tributaries of the Niantic River estuary, southeastern Connecticut, 2005 and 2008–2011

    Science.gov (United States)

    Mullaney, John R.

    2013-01-01

    Nutrient concentrations and loads and Escherichia coli (E. coli) densities were studied in 2005 and from 2008 through 2011 in water-quality samples from tributaries of the Niantic River Estuary in southeastern Connecticut. Data from a water-quality survey of the base flow of subbasins in the watershed in June 2005 were used to determine the range of total nitrogen concentrations (0.09 to 2.4 milligrams per liter), instantaneous loads (less than 1 to 62 pounds per day) and the yields of total nitrogen ranging from 0.02 to 11.2 pounds per square mile per day (less than 1 to 7.2 kilograms per hectare per year) from basin segments. Nitrogen yields were positively correlated with the amount of developed land in each subbasin. Stable isotope measurements of nitrate (δ15N) and oxygen (δ18O) ranged from 3.9 to 9.4 per mil and 0.7 to 4.1 per mil, respectively, indicating that likely sources of nitrate in base flow are soil nitrate and ammonium fertilizers, sewage or animal waste, or a mixture of these sources. Continuous streamflow and monthly water-quality sampling, with additional storm event sampling, were conducted at the three major tributaries (Latimer Brook, Oil Mill Brook, and Stony Brook) of the Niantic River from October 2008 through September 2011. Samples were analyzed for nitrogen and phosphorus constituents and E. coli densities. Total freshwater discharge from these tributaries, which is reduced by upstream withdrawals, ranged from 25.9 to 37.8 million gallons per day. Total nitrogen and phosphorus concentrations generally were low, with the mean values below the U.S. Environmental Protection Agency recommended nutrient concentration values of 0.71 milligram per liter and 0.031 milligram per liter, respectively. Total nitrogen was predominantly in the form of total ammonia plus organic nitrogen at the Oil Mill Brook and Stony Brook sites and in the form of nitrate at Latimer Brook. Annual total nitrogen loads that flowed into the Niantic River estuary from

  3. SEDIMENT TRANSPORT IN THE YANGTZE RIVER ESTUARY

    Institute of Scientific and Technical Information of China (English)

    SHEN Zhigang

    2001-01-01

    The hydrodynamic and the sediment transport patterns within the estuary of the Yangtze River are complex because of interaction of fluvial and the tidal forces, depending on freshwater discharge and tidal range. Based on the data measured in recent years, this paper discusses the characteristics of flow and sediment movement in the Yangtze River Estuary and their influences on the evolution of the estuary.

  4. Response of gaseous carbon emissions to low-level salinity increase in tidal marsh ecosystem of the Min River estuary, southeastern China.

    Science.gov (United States)

    Hu, Minjie; Ren, Hongchang; Ren, Peng; Li, Jiabing; Wilson, Benjamin J; Tong, Chuan

    2017-02-01

    Although estuarine tidal marshes are important contributors to the emission of greenhouse gases into the atmosphere, the relationship between carbon dioxide (CO2), methane (CH4) emission, and environmental factors, with respect to estuarine marshes, has not been clarified thoroughly. This study investigated the crucial factors controlling the emission of CO2 and CH4 from a freshwater marsh and a brackish marsh located in a subtropical estuary in southeastern China, as well as their magnitude. The duration of the study period was November 2013 to October 2014. Relevant to both the field and incubation experiments, the CO2 and CH4 emissions from the two marshes showed pronounced seasonal variations. The CO2 and CH4 emissions from both marshes demonstrated significant positive correlations with the air/soil temperature (prise and saltwater intrusion could reduce the CH4 emissions from the estuarine freshwater marshes, these factors had little effect on the CO2 emissions with respect to an increase in salinity of less than 5‰. The findings of this study could have important implications for estimating the global warming contributions of estuarine marshes along differing salinity gradients.

  5. Large wood in the Snowy River estuary, Australia

    Science.gov (United States)

    Hinwood, Jon B.; McLean, Errol J.

    2017-02-01

    In this paper we report on 8 years of data collection and interpretation of large wood in the Snowy River estuary in southeastern Australia, providing quantitative data on the amount, sources, transport, decay, and geomorphic actions. No prior census data for an estuary is known to the authors despite their environmental and economic importance and the significant differences between a fluvial channel and an estuarine channel. Southeastern Australian estuaries contain a significant quantity of large wood that is derived from many sources, including river flood flows, local bank erosion, and anthropogenic sources. Wind and tide are shown to be as important as river flow in transporting and stranding large wood. Tidal action facilitates trapping of large wood on intertidal bars and shoals; but channels are wider and generally deeper, so log jams are less likely than in rivers. Estuarine large wood contributes to localised scour and accretion and hence to the modification of estuarine habitat, but in the study area it did not have large-scale impacts on the hydraulic gradients nor the geomorphology.

  6. Heavy metals in Mindhola river estuary, India

    Digital Repository Service at National Institute of Oceanography (India)

    Zingde, M.D.; Rokade, M.A; Mandalia, A

    The heavy metal concentrations are studied along the Mindhola river estuary. Surface and bottom water samples were collected using Niskin Sampler. The sediment samples were collected using a Van Veen grab. The heavy metal concentration is estimated...

  7. (CLUPEIDAE) FROM CROSS RIVER ESTUARY, NIGERIA

    African Journals Online (AJOL)

    Scales and sand were secondary items while macrophyte matters ... the same item throughout the years, the food resources were considered important factor in the elimination of the fish ... ecology of this fish from the Cross River estuary,.

  8. Birds of Mahi River estuary, Gujarat, India

    Directory of Open Access Journals (Sweden)

    P.J. Pandya

    2010-06-01

    Full Text Available The Mahi river estuary is one of the major estuaries of Gujarat. This paper presents a comprehensive list of birds of the Mahi river estuary (nearly 50 km stretch and the adjacent banks/ravines and defines the avian diversity at three major estuarine gradations with a brief check of similarity and diversity within the three. The present observation is the outcome of a 3 year period from August 2006 to July 2009. A sum total of 118 species belonging to 42 families were reported and listed as on Upstream, Midstream, and Downstream of estuary. No significant difference was seen in the species richness at the three zones; a change in avian composition at upstream and downstream was notable.

  9. Effects of the addition of nitrogen and sulfate on CH4 and CO2 emissions, soil, and pore water chemistry in a high marsh of the Min River estuary in southeastern China.

    Science.gov (United States)

    Hu, Minjie; Wilson, Benjamin J; Sun, Zhigao; Ren, Peng; Tong, Chuan

    2017-02-01

    Exogenous nitrogen (N) and sulfate (SO4(2-)), resulting from human activity, can strongly influence the emission of CH4 and CO2 from soil ecosystems. Studies have reported the effects of N and SO4(2-) on CH4 and CO2 emissions from inland peatlands and paddies. However, very few studies have presented year-round data on the effects of the addition of N and SO4(2-) on CH4 and CO2 emissions in estuarine marshes. The effects of the addition of N and SO4(2-) on the emission of CH4 and CO2 were investigated in a Cyperus malaccensis marsh in the high tidal flat of the Min River estuary of southeastern China from September 2014 to August 2015. Dissolved NH4Cl, KNO3, and K2SO4 were applied every month, in doses of 24gN/SO4(2-)m(-2)·yr(-1). The emission of CH4 and CO2 showed distinct monthly and seasonal variations. Compared with the control, the addition of NH4Cl and NH4NO3+K2SO4 showed increases in CH4 fluxes (p0.05). NH4Cl had a positive impact on CO2 emissions (p0.05). Correlation analysis found that soil sulfate concentration, nitrogen availability and enzyme activity were the dominant factors influencing CH4 and CO2 variation. Our findings suggest that CH4 and CO2 emissions were influenced more by ammonium than by nitrate. We propose that the suppressive effect of additional sulfate on CH4 production is insignificant, due to which the inhibition may be overestimated in the estuarine brackish marsh.

  10. Estuary-wide genetic stock distribution - Columbia River Estuary Tidal Habitats

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The goal of the tidal-fluvial estuary study is to determine the estuary's contribution to the spatial structure and life history diversity of Columbia River salmon...

  11. Salmon habitat use, tidal-fluvial estuary - Columbia River Estuary Tidal Habitats

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The goal of the tidal-fluvial estuary study is to determine the estuary's contribution to the spatial structure and life history diversity of Columbia River salmon...

  12. In-stream PIT detection, estuary wetlands - Columbia River Estuary Tidal Habitats

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The goal of the tidal-fluvial estuary study is to determine the estuary's contribution to the spatial structure and life history diversity of Columbia River salmon...

  13. The importance of the river-estuary interface (REI) zone in estuaries

    African Journals Online (AJOL)

    drinie

    2002-07-03

    Jul 3, 2002 ... tendency to block during times of low river inflow to scour events during river flooding. .... occurred, causing the river to form a series of discrete pools. When ..... Average phytoplankton chlorophyll-a for the whole estuary was.

  14. Skagit IMW - Skagit River Estuary Intensively Monitored Watershed Project

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This study evaluates system-level effects of several estuary restoration projects on juvenile Chinook salmon production in the Skagit River estuary. The monitoring...

  15. Historical changes in the Columbia River Estuary

    Science.gov (United States)

    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

  16. Investigation on Water Pollution of Four Rivers in Coastal Wetland of Yellow River Estuary

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    [Objective] The study aimed at analysing water pollution of four rivers in coastal wetland of Yellow River estuary. [Method] Taking four seriously polluted rivers (Guangli River, Shenxian Ditch, Tiao River and Chao River) in coastal wetland of Yellow River estuary as study objects, water samples were collected from the four rivers in May (dry period), August (wet period) and November (normal period) in 2009 and 2010 respectively, then pollution indices like nutritive salts, COD, chlorophyll-a, petroleum, et...

  17. SEDIMENT TRANSPORT IN YALU RIVER ESTUARY

    Institute of Scientific and Technical Information of China (English)

    GAO Jian-hua; GAO Shu; CHENG Yan; DONG Li-xian; ZHANG Jing

    2003-01-01

    Tidal cycle measurements of tidal currents, salinity and water temperature, and suspended sediment conc entra-tions were measured at four stations, together with surveys along two profiles short core collection within the Yalu River estuary.Grain size analysis of the three core sediment showed that: 1) the sediment from B1 to B3 became finer, worse sorting andpositively skewed; 2) the diversification of matter origin became more and more evident from east to west; 3) the sediments overthe region were of the same origin, as indicated by their similar colors and grain sizes. The data indicated that stratiticationoccurred in the flood season, from upstream to downstream, and a salt wedge was formed. The water column was well mixed, butthe longitudinal gradient of the salinity was larger on spring tide. The results also showed that the dominating mechanisnt ofsuspended sediment transport in the Yalu River estuary was T1, T2, T3 and T5. The non-tidal steady advection transport wasrestricted by the net transport of suspended sediment induced by mass Stoked drift directed to landwards, then the net sedimenttransport rate were decreased and the turbidity maxima was also favored to forming and extending.

  18. Estuary fish data - Juvenile salmon in migratory corridors of lower Columbia River estuary

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Sampling juvenile salmon and associated fishes in open waters of the lower Columbia River estuary. Field work includes bi-weekly sampling during the spring...

  19. Columbia River Estuary Ecosystem Classification Hydrogeomorphic Reach

    Science.gov (United States)

    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

  20. Columbia River Estuary Ecosystem Classification Geomorphic Catena

    Science.gov (United States)

    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

  1. Columbia River Estuary Ecosystem Classification Ecosystem Complex

    Science.gov (United States)

    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

  2. Short term variations in particulate matter in Mahi river estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Bhosle, N.B.; Rokade, M.A.; Zingde, M.D.

    The particulate matter (PM) collected from Mahi River Estuary was analysed for organic carbon (POC), nitrogen (PON), and chlorophyll a (Chl a). The concentration of PM, POC, PON and Chl a showed short term variations. Average surface concentration...

  3. St. Louis River Estuary 2011 - 2013 Faucet snail location data

    Data.gov (United States)

    U.S. Environmental Protection Agency — The dataset consists of GPS coordinates for benthic invertebrate collections made in the St. Louis River Estuary in 2011 through 2013, and information on whether and...

  4. Juvenile salmon usage of the Skeena River estuary.

    Science.gov (United States)

    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

  5. The Mntafufu and Mzamba River estuaries

    African Journals Online (AJOL)

    1989-03-14

    Mar 14, 1989 ... forested coastal belt of Transkei and have relatively small estuaries (5 and 2 km long, .... biological data is available for the Mntafufu or Mzamba ... kilometre inland the lagoon narrows, from where the estuary ...... An analysis of the data from the Kei (plumstead et al. ..... Factors influencing the utilization of.

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

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

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

  7. Anthropogenic tritium in the Loire River estuary, France

    Science.gov (United States)

    Péron, O.; Gégout, C.; Reeves, B.; Rousseau, G.; Montavon, G.; Landesman, C.

    2016-12-01

    This work is carried out in the frame of a radioecological monitoring of anthropogenic tritium from upstream and downstream of several nuclear power plants along the Loire River to its estuary. This paper studies the variation of anthropogenic tritium species in the Loire River system from upstream to the mouth of the estuary. Tritiated water (HTO and HTO in sediment pore water) and organically bound tritium (OBT) forms were analysed after dedicated pre-treatments. The collected environmental samples consist in (i) surface-sediment and core samples from the river floor, (ii) surface and water column samples. A maximum 3H activity concentration of 26 ± 3 Bq·L- 1 in the Loire River estuary is obtained whereas an environmental background level around 1 Bq·L- 1 is determined for a non influenced continental area by anthropogenic activities. The European follow-up indicator used as a screening value is 100 Bq·L- 1. The conservative tritium behaviour was used in order to characterize the tidal regime and river flow influences in the mixing zone of the Loire River estuary. Furthermore, OBT levels and total organically carbon (TOC) content are explored. Finally, ratios of OBT relative to HTO in sediment pore water in surface-sediment and core samples are also discussed.

  8. Biogeochemistry of the Kem' River estuary, White Sea (Russia

    Directory of Open Access Journals (Sweden)

    V. R. Shevchenko

    2005-01-01

    Full Text Available The biogeochemistry of the river-sea interface was studied in the Kem' River (the largest river flowing to the White Sea from Karelian coast estuary and adjacent area of the White Sea onboard the RV 'Ekolog' in summer 2001, 2002 and 2003. The study area can be divided into 3 zones: I - the estuary itself, with water depth from 1 to 5m and low salinity in the surface layer (salinity is lower than 0.2psu in the Kem' River and varies from 15 to 20psu in outer part of this zone; II - the intermediate zone with depths from 5 to 10m and salinity at the surface from 16 to 22psu; III - the marine zone with depths from 10 to 29 m and salinity 21-24.5psu. Highest concentrations of the suspended particulate matter (SPM were registered in the Kem' mouth (5-7mg/l. They sharply decreased to values org to nitrogen (N ratio (Corg/N in both suspended matter and bottom sediments decreases from the river to the marine part of the mixing zone (from 8.5 to 6.1 in the suspended matter and from 14.6 to 7.5 in the bottom sediments, demonstrating that content of terrestrial-derived organic matter decreases and content of marine organic matter increases from the river mouth to the sea. The Kem' estuary exhibits a similar character of biogeochemial processes as in the large Arctic estuaries, but the scale of these processes (amount of river input of SPM, POC, area of estuaries is different.

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

    Science.gov (United States)

    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...

  10. River flow and fish abundance in a South African estuary

    CSIR Research Space (South Africa)

    Whitfield, AK

    2003-06-01

    Full Text Available The ichthyofauna of the Thukela Estuary, a small (55 ha), shallow (<1_5 m) system on the KwaZulu-Natal coast (mean annual river runoff of 3865_106m3, from a large catchment of29 000km2, is seasonal: peak inputs occurring between November and March...

  11. Sedimentation in a river dominated estuary

    CSIR Research Space (South Africa)

    Cooper, JAG

    1993-10-01

    Full Text Available The Mgeni Estuary on the wave dominated cast coast of South Africa occupies a narrow, bedrock confined, alluvial valley and is partially blocked at the coast by an elongate sandy barrier. Fluvial sediment extends to the barrier and marine depositon...

  12. Hydrodynamics of the Bot river estuary revisited

    CSIR Research Space (South Africa)

    Van Niekerk, L

    2005-01-01

    Full Text Available For the past 20 years management of the Bot/Kleinmond estuarine system in the south-western Cape has been based on the premise that, barring intervention, the estuary was naturally evolving into a freshwater coastal lake. This paper presents...

  13. Flushing characteristics of Mahim river estuary (Bombay)

    Digital Repository Service at National Institute of Oceanography (India)

    Sabnis, M.M.; Zingde, M.D.

    to the influence of wastewater. Flushing time of 19 tidal cycles was estimated by applying modified tidal prism method. After a large number of tidal cycles the estuary would retain 9.3x10 super(4) m super(3) of wastewater which was over 15% of the spring high tide...

  14. Population characteristics of the swimming crab Callinectes amnicola De Rocheburne, 1883 (Crustacea, Brachyura, Portunidae in the Qua Iboe River estuary, Nigeria

    Directory of Open Access Journals (Sweden)

    James P. Udoh

    2011-07-01

    Full Text Available Aspects of the biology of Callinectes amnicola, from the Qua Iboe River estuary, south-eastern Nigeria, was investigated for twelve months from June 2008 to May 2009, with respect to its size composition and population characteristics. A total of 1,193 specimens were obtained comprising 508males and 685 females with overall (1:1.35, χ2 = 26.26, 1 df, p 2 =2.17, I df, p 2 = 11.44, 1 df, p C. amnicola inhabiting the lower reaches of the Qua Iboe River estuary, Nigeria.

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

    Science.gov (United States)

    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.

  16. Modeling Residual Circulation and Stratification in Oujiang River Estuary

    Institute of Scientific and Technical Information of China (English)

    LIN Wei-bo; WANG Yi-gang; RUAN Xiao-hong; XU Qun

    2012-01-01

    A 3D,time-dependent,baroclinic,hydrodynamic and salinity model was implemented and applied to the Oujiang River estuarine system in the East China Sea.The model was driven by the forcing of tidal elevations along the open boundaries and freshwater inflows from the Oujiang River.The bottom friction coefficient and vertical eddy viscosity were adjusted to complete model calibration and verification in simulations.It is demonstrated that the model is capable of reproducing observed temporal variability in the water surface elevation and longitudinal velocity,presenting skill coefficient higher than 0.82.This model was then used to investigate the influence of freshwater discharge on residual current and salinity intrusion under different freshwater inflow conditions in the Oujiang River estuary.The model results reveal that the river channel presents a two-layer structure with flood currents near the bottom and ebb currents at the top layer in the region of seawater influenced on north shore under high river flow condition.The river discharge is a major factor affecting the salinity stratification in the estuarine system.The water exchange is mainly driven by the tidal forcing at the estuary mouth,except under high river flow conditions when the freshwater extends its influence from the river's head to its mouth.

  17. Geographic specificity of Aroclor 1268 in bottlenose dolphins (Tursiops truncatus) frequenting the Turtle/Brunswick River Estuary, Georgia (USA).

    Science.gov (United States)

    Pulster, Erin L; Maruya, Keith A

    2008-04-15

    Coastal marine resources are at risk from anthropogenic contaminants, including legacy persistent organic pollutants (POPs) with half-lives of decades or more. To determine if polychlorinated biphenyl (PCB) signatures can be used to distinguish among local populations of inshore bottlenose dolphins (Tursiops truncatus) along the southeastern U.S. coast, blubber from free-ranging and stranded animals were collected along the Georgia coast in 2004 and analyzed for PCB congeners using gas chromatography with electron capture and negative chemical ionization mass spectrometric detection (GC-ECD and GC-NCI-MS). Mean total PCB concentrations (77+/-34 microg/g lipid) were more than 10 fold higher and congener distributions were highly enriched in Cl(7)-Cl(10) homologs in free-ranging animals from the Turtle/Brunswick River estuary (TBRE) compared with strandings samples from Savannah area estuaries 90 km to the north. Using principal components analysis (PCA), the Aroclor 1268 signature associated with TBRE animals was distinct from that observed in Savannah area animals, and also from those in animals biopsied in other southeastern U.S estuaries. Moreover, PCB signatures in dolphin blubber closely resembled those in local preferred prey fish species, strengthening the hypothesis that inshore T. truncatus populations exhibit long-term fidelity to specific estuaries and making them excellent sentinels for assessing the impact of stressors on coastal ecosystem health.

  18. Geographic specificity of Aroclor 1268 in bottlenose dolphins (Tursiops truncatus) frequenting the Turtle/Brunswick River Estuary, Georgia (USA)

    Energy Technology Data Exchange (ETDEWEB)

    Pulster, Erin L. [Marine Sciences Department, Savannah State University, Savannah, Georgia, 31404 (United States); Skidaway Institute of Oceanography, 10 Ocean Science Circle, Savannah, Georgia, 31411 (United States)], E-mail: epulster@mote.org; Maruya, Keith A. [Skidaway Institute of Oceanography, 10 Ocean Science Circle, Savannah, Georgia, 31411 (United States)

    2008-04-15

    Coastal marine resources are at risk from anthropogenic contaminants, including legacy persistent organic pollutants (POPs) with half-lives of decades or more. To determine if polychlorinated biphenyl (PCB) signatures can be used to distinguish among local populations of inshore bottlenose dolphins (Tursiops truncatus) along the southeastern U.S. coast, blubber from free-ranging and stranded animals were collected along the Georgia coast in 2004 and analyzed for PCB congeners using gas chromatography with electron capture and negative chemical ionization mass spectrometric detection (GC-ECD and GC-NCI-MS). Mean total PCB concentrations (77 {+-} 34 {mu}g/g lipid) were more than 10 fold higher and congener distributions were highly enriched in Cl{sub 7}-Cl{sub 10} homologs in free-ranging animals from the Turtle/Brunswick River estuary (TBRE) compared with strandings samples from Savannah area estuaries 90 km to the north. Using principal components analysis (PCA), the Aroclor 1268 signature associated with TBRE animals was distinct from that observed in Savannah area animals, and also from those in animals biopsied in other southeastern U.S estuaries. Moreover, PCB signatures in dolphin blubber closely resembled those in local preferred prey fish species, strengthening the hypothesis that inshore T. truncatus populations exhibit long-term fidelity to specific estuaries and making them excellent sentinels for assessing the impact of stressors on coastal ecosystem health.

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

    Science.gov (United States)

    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

  20. Macrobenthic Community in the Xiaoqing River Estuary in Laizhou Bay, China

    Institute of Scientific and Technical Information of China (English)

    LUO Xianxiang; ZHANG Shanshan; YANG Jianqiang; PAN Jinfen; TIAN Lin; ZHANG Longjun

    2013-01-01

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

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

    Science.gov (United States)

    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.

  2. Estimation of Bed Shear Stresses in the Pearl River Estuary

    Institute of Scientific and Technical Information of China (English)

    刘欢; 吴加学

    2015-01-01

    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.

  3. Methodology for estimation of river discharge and applicationof the Zhujiang River Estuary (ZRE)

    Institute of Scientific and Technical Information of China (English)

    CHENJay-Chung; WONGLai-Ah

    2004-01-01

    The ZRE is a very complicated estuary with multi-river inlets. The total sum of river discharge in the upstream(away from the tidal influence region) of the Zhujiang River can be easily measured. However, when the total river discharges into the estuary from eight inlets, it is a very difficult task to obtain a continuous river discharge flux data from each branch of the Zhujiang River. However, the different ratios of river discharges between the river branches can significantly affect the estuarine circulation feature and baroclinic process. Moreover, the accuracy of numerical forecast for the estuarine circulation is very much dependent on the accuracy of the time history of the river discharge flux for each branch. Therefore, it is important to estimate river discharge from each branch in order to improve the accuracy of the model forecast for the circulation of the ZRE. The development of a new estimation method of the river discharges is focused on based on the system identification theory, numerical modeling and the time history data from the CODAR observed sea surface current. The new approach has been appfied to estimating the time history (hourly) of river discharge from each branch in the upstream of the ZRE.

  4. Estimation of dissolved inorganic nutrients fluxes from the Changjiang River into estuary

    Institute of Scientific and Technical Information of China (English)

    刘新成; 沈焕庭

    2001-01-01

    Because the estuary acts as either a trap or a source or both for nutrient elements and will modify greatly the riverine transport to the ocean, it is necessary to calculate the flux from river into estuary and that from estuary into sea, respectively. The present work aims to use a long-term record of nutrients concentrations and runoff discharges on H.e Datong section (625 km inland from the Changjiang River mouth) to identify the variability of nutrients concentrations and to estimate nutrients fluxes from the Changjiang River into the estuary.

  5. Sedimentary framework of the Potomac River estuary, Maryland

    Science.gov (United States)

    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.

  6. Analysis of Cu and Pb in the sediments of Kakum River, its estuary ...

    African Journals Online (AJOL)

    DR GATSING

    This paper discusses the levels of some heavy metals (Cu and Pb) in the soil sediments of the Kakum. River, its estuary and ... Keywords: River Kakum, soil sediment, Copper and Lead. ..... and active tailings pile in the State of. Mexico.

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

    Science.gov (United States)

    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

  8. Quantifying nitrogen inputs to the Choptank River estuary

    Science.gov (United States)

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

    2015-12-01

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

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

    Science.gov (United States)

    Goldstein, Steven J.; Jacobsen, Stein B.

    1988-05-01

    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.

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

    Science.gov (United States)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  12. Determination of petroleum hydrocarbons in sediment samples from Bombay harbour, Dharamtar creek and Amba river estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Ingole, S.A.; Dhaktode, S.S.; Kadam, A.N.

    The surface sediment samples were collected by van Veen grab sampler during premonsoon, monsoon and postmonsoon seasons from Bombay harbour, Dharamtar creek and Amba river estuary Moisture content of the samples ranges from 36 to 67.5...

  13. 2009 Puget Sound LiDAR Consortium (PSLC) Topographic LiDAR: Snohomish River Estuary

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Watershed Sciences, Inc. (WS) co-acquired Light Detection and Ranging (LiDAR) data and Truecolor Orthophotographs of the Snohomish River Estuary, WA on July 20 &...

  14. Characteristics of Sediments in the James River Estuary, Virginia, 1968 (NODC Accession 7001081)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This report presents data on the physical and chemical characteristics of bottom sediments in the James River estuary, Virgina. The data were generated as part of a...

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

    Science.gov (United States)

    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...

  16. Sediment grain size in the Elwha River estuary, Washington, from 2013 and 2014.

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This portion of the data release presents sediment grain-size data from samples collected in the Elwha River estuary, Washington, in July 2013 and June 2014 (USGS...

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

    Science.gov (United States)

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

  18. Fish abundance in the Elwha River estuary, Washington, from 2006 to 2014

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This portion of the data release presents fish abundance data from samples collected in the Elwha River estuary, Washington, in 2006, 2007, 2013, and 2014 (no...

  19. Riparian vegetation abundance (percent cover) in the Elwha River estuary, Washington, in 2007 and 2014

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This portion of the data release presents riparian plant species abundance (percent cover) data from plots sampled in the Elwha River estuary, Washington, in 2007...

  20. Riparian vegetation species richness in the Elwha River estuary, Washington, in 2007 and 2014

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This portion of the data release presents riparian plant species richness (number of unique taxa) data from plots sampled in the Elwha River estuary, Washington, in...

  1. Physical aspects of estuarine pollution - A case study in Amba river estuary

    Digital Repository Service at National Institute of Oceanography (India)

    DineshKumar, P.K.; Josanto, V.; Sarma, R.V.; Zingde, M.D.

    Tide dominated Amba river estuary was studied to evaluate it's physical characteristics with a point on application to locate a suitable release point of industrial effluents. It is important to site the outfall in a manner ensuring that the water...

  2. Aquatic invertebrate abundance in the Elwha River estuary, Washington, in 2007 and 2013

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This portion of the data release presents aquatic invertebrate abundance data from samples collected in the Elwha River estuary, Washington, in 2007 and 2013 (no...

  3. Nutrient dynamics in mangrove areas of the Red River Estuary in Vietnam

    Science.gov (United States)

    Wösten, J. H. M.; de Willigen, P.; Tri, N. H.; Lien, T. V.; Smith, S. V.

    2003-05-01

    Nutrient dynamics of mangrove in the 107 km 2 large estuary of the Red River Delta in Vietnam are studied using the existing LOICZ-CABARET budget model. The methodology and assumptions underlying this model are described. Input data for evaporation, rainfall, river discharge, and concentrations of salt, phosphorus and nitrogen are obtained during measurement campaigns in Vietnam. The calculated P-balance of the estuary together with measured data on the C/P ratio of mangroves yield a calculated mangrove biomass growth rate of 80 kg dry matter ha -1 d -1. Direct measurements of mangrove growth show a rate of 31 kg dry matter ha -1 d -1. Considering the uncertainties involved in this study where nutrient exchange with mineral particles is ignored, the nutrient budget model established for the Red River Estuary proves to give acceptable results. The model demonstrates that the mangroves in the estuary act as clear sinks of nutrients and sequester some 26 000 kg N d -1 and some 3100 kg P d -1 for their biomass production. Next the model is used in an explorative way to investigate effects of realistic future scenarios. Increasing river discharge in combination with constant or proportionally increasing river nutrient concentration results in increasing nutrient concentrations in the estuary. Increasing river discharge in combination with decreasing river nutrient concentration results in decreasing nutrient concentrations in the estuary. Constant river discharge in combination with increasing river nutrient concentration results in increasing nutrient concentrations in the estuary. The scenario analysis helps to understand the different interactions in the nutrient dynamics of the Red River mangrove area.

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

    Science.gov (United States)

    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

  5. Heavy Metallic Element Distribution in Cisadane River Estuary's Water and Sediment

    Directory of Open Access Journals (Sweden)

    M. Taufik Kaisupy

    2006-04-01

    Full Text Available Observation of heavy metallic elements in Cisadane River Estuary has been done in July and November 2005. The results show that heavy metallic elements content in seawater is lower and still below the treshold value stated by government for fisheries. There was an indication of heavy metallic elements on sediment. Distribution of Pb on July and of Cu on November 2005 were found higher near the coast and decrease towards the sea, and commonly were found in front of estuary such as Cisadane, Muara Saban and Tanjung Pasir. High Pb and Zn distributions on November 2005 were found only in front of Cisadane estuary. Cd distribution of Cisadane estuary was constant at all station but did not show any correlation with the distance of station and estuary. The Cd content on July and November 2005 is lower than 0,001 ppm. Generally, heavy metallic elements content have a uniform distribution at all stations inspite of its distance to estuary.

  6. Temporal and spatial changes of suspended sediment concentration and resuspension in the Yangtze River estuary

    Institute of Scientific and Technical Information of China (English)

    CHENShenliang; ZHANGGuoan; YANGShilun

    2003-01-01

    A detailed analysis of suspended sediment concentration (SSC) variations over a year period is presented using the data from 8 stations in the Yangtze River estuary and its adjacent waters, together with a discussion of the hydrodynamic regimes of the estuary. Spatially, the SSC from Xuliujing downwards to Hangzhou Bay increases almost constantly, and the suspended sediment in the inner estuary shows higher concentration in summer than in winter, while in the outer estuary it shows higher concentration in winter than in summer, and the magnitude is greater in the outer estuary than in the inner estuary, greater in the Hangzhou Bay than in the Yangtze River estuary. The sediments discharged by the Yangtze River into the sea are resuspended by marine dynamics included tidal currents and wind waves. Temporally, the SSC shows a pronounced neap-spring tidal cycle and seasonal variations. Furthermore, through the analysis of dynamic mechanism, it is concluded that wave and tidal current are two predominant factors of sediment resuspension and control the distribution and changes of SSC, in which tidal currents control neap-spring tidal cycles, and wind waves control seasonal variations. The ratio between river discharge and marine dynamics controls soatial distribution of SSC.

  7. Estimating salinity intrusion effects due to climate change on the Lower Savannah River Estuary

    Science.gov (United States)

    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

    alternative scenarios of interest. Important freshwater resources are located proximal to the freshwater-saltwater interface of the estuary. The Savannah National Wildlife Refuge is located in the upper portion of the Savannah River Estuary. The tidal freshwater marsh is an essential part of the 28,000-acre refuge and is home to a diverse variety of wildlife and plant communities. Two municipal freshwater intakes are located upstream from the refuge. To evaluate the impact of climate change on salinity intrusion on these resources, inputs of streamflows and mean tidal water levels were modified to incorporate estimated changes in precipitation patterns and sea-level rise appropriate for the Southeastern United States. Changes in mean tidal water levels were changed parametrically for various sea-level rise conditions. Preliminary model results at the U.S. Geological Survey (USGS) Interstate-95 streamgage (station 02198840) for a 7½-year simulation show that historical daily salinity concentrations never exceeded 0.5 practical salinity units (psu). A 1-foot sea-level rise (ft, 30.5 centimeters [cm]) would increase the number of days of salinity concentrations greater than 0.5 psu to 47 days. A 2-ft (61 cm) sea-level rise would increase the number of days to 248.

  8. Modeling transportation of suspended solids in Zhujiang River estuary, South China

    Institute of Scientific and Technical Information of China (English)

    CHEN Xiaohong; CHEN Yongqin; LAI Guoyou

    2005-01-01

    A three-dimensional transportation model for suspended solids (SS) in Zhujiang (Pearl) River estuary, South China, was developed by coupling with a three-dimensional hydrodynamic model. The model was validated using hourly measured data of sediment contents during 25-26, July 1999. The results showed that modeled contents matched well with measured ones and that the modeled top layer distribution agreed with the remotely sensed image of suspended solids in summer. The modeled results showed clearly the layers of suspended solids in depth, with larger sediment contents in lower layers though in the interface between salt water and freshwater the lowest contents appeared in middle layer. In overall, the suspended solids inflow from 8 rivers, transport southwestward, and carried by strong coastal flow in Zhujiang River estuary. Contours of sediment contents in the estuary spread further to the open sea during ebb tide rather than flood tide which reflects that the suspended solids in the estuary are land sourced.

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

    Science.gov (United States)

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

    2009-08-01

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

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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. Trace Element Signatures of Particles in the Fraser River Estuary

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Gary E.; Diefenderfer, Heida L. (Pacific Northwest National Laboratory)

    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

  16. Pollution in the estuary of the Baracoa river, La Habana, Cuba

    Directory of Open Access Journals (Sweden)

    Regla Duthit Somoza

    2011-04-01

    Full Text Available The environmental quality of the Baracoa river estuary was studied from the physic (temperature and salinity, chemic variables (dissolved oxygen, oxygen biochemical demand (DBO, oxygen chemical demand (DQO, nitrogen cycle, inorganic phosphorus and total phosphorus and the microbiological variables (total and thermotolerant coliforms and faecal streptococci. The samplings were made on February 2006, May and October 2007. Spatial distribution of the physical and chemical parameters measured suggests that the estuary is dominated by the marine conditions. The salinity and temperature analyses show that in general the characteristics of the estuary could be influenced by the contribution of the river basin drainage. In general, the concentrations of the measured parameters in the Baracoa river estuary, strongly suggest that this area is under influence of human activities on the river basin, due to the low levels of dissolved oxygen and an oxygen average deficit of -1.6 mg/L. nthropogenic actions in this estuary are mainly related to the emission of domestic and farming rejects without suitable treatment. This is visibly associated with the observed values of the total coliforms concentrations as well as the concentration of faecal streptococci, that surpassed reference values from the Cuban norm for water quality, following on bad or doubtful quality levels pointing out negatively measurements made next to the communication channel the estuary and the El Doctor lagoon.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  18. Heavy metals in bivalves collected from river estuaries of Thailand. [Perna viridis

    Energy Technology Data Exchange (ETDEWEB)

    Menasveta, P.; Cheevapora, V.; Wongwit, C.

    1984-01-01

    This investigation was undertaken to determine the levels of lead, zinc, copper, cadmium, and mercury in five species of bivalves collected from six river estuaries of Thailand during July 1978 to January 1979. The in situ bioassay for studying heavy metals uptake by green mussels (Perna viridis) was also conducted at the Chao Phraya river estuary during February 1980 to March 1981. The results revealed high contamination of lead in mussels during the period of river run-off. The factors that might contribute to this incidence were discussed. Contaminations of the other four metals in bivalves did not show great variation and they were still within the acceptable limits.

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

    Science.gov (United States)

    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.

  20. VISION, STRATEGY AND ACTION PLAN FOR SHELLFISH FARMING DEVELOPMENT IN THE KRKA RIVER ESTUARY

    Directory of Open Access Journals (Sweden)

    Drago Maguš

    2009-10-01

    Full Text Available In this paper are presented the vision, strategic guidelines/measures and the action plan for shellfish farming development in the Krka river estuary. They came as a result from several discussions that were held with shellfish farmers of the estuary area in year 2008 while writing the Integrated Plan for Shellfish Farming for Krka Estuary Area, which was realized in the framework of the Green Business Support Programme (UNDP COST Project — Conservation, and Sustainable Use of Biodiversity in the Dalmatian Coast through Greening Coastal Development. For a short–term, a considerable impetus for the development of shellfish farming in the Krka river estuary could be the construction of common distribution and purification center, building of warehouse for shellfish farming equipment, and providing work space for the preparation of the equipment as well as the space for waste disposal; for a long–term it could be building of shellfish hatchery at the location of Martinska marine station.

  1. A Contaminants Evaluation of the Big Blue River in Southeastern Nebraska

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — We collected three composite fish and three composite sediment samples from the Big Blue River in southeastern Nebraska to determine the presence of agricultural...

  2. Trace elements and organic compounds in the Spring River Basin of southeastern Kansas in 1988

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — We sampled sediments and aquatic biota at five locations in the Spring River drainage in southeastern Kansas. The samples were analyzed for metals, organochlorine...

  3. Estimation of total suspended matter in the Zhujiang (Pearl)River estuary from Hyperion imagery

    Institute of Scientific and Technical Information of China (English)

    LIU Dazhao; FU Dongyang; XU Bing; SHEN Chunyan

    2012-01-01

    Although remote sensing data have been used to estimate total suspended matter (TSM) in coastal waters,it has limitations when applied to estuary waters in low spatial resolution situations.The spatial resolution of ocean color satellites such as SeaWiFS and MODIS is usually ~1 km,and therefore is not adequate for small,local-scale areas such as the Zhujiang (Pearl) River estuary.In contrast,30 m-resolution EO-1 Hyperion imagery has potential for studying TSM in localized areas.We measured the surface spectral radiance reflectance of the river estuary water in the visible and near infra-red spectral range.Sensitivity analysis indicated that the ratio of remote sensing reflectance at 813 nm (Rrs(813)) to reflectance at 559 nm (Rrs(559)) could be used to estimate TSM concentration,and a linear relationship was established between the ratio and in-situ TSM concentration.We applied the linear relationship to Hyperion imagery to map TSM concentration in the estuary.The Hyperion imagery provided sufficient spatial resolution to detect spatiotemporal changes in TSM concentrations in the estuary small estuary area.This study demonstrated the usefulness of Hyperion imagery for mapping the distribution of TSM in estuary waters.

  4. Modeling the impact of river discharge and wind on the hypoxia off Yangtze Estuary

    Science.gov (United States)

    Zheng, Jingjing; Gao, Shan; Liu, Guimei; Wang, Hui; Zhu, Xueming

    2016-12-01

    The phenomenon of low dissolved oxygen (known as hypoxia) in a coastal ocean system is closely related to a combination of anthropogenic and natural factors. Marine hypoxia occurs in the Yangtze Estuary, China, with high frequency and long persistence. It is related primarily to organic and nutrient enrichment influenced by river discharges and physical factors, such as water mixing. In this paper, a three-dimensional hydrodynamic model was coupled to a biological model to simulate and analyze the ecological system of the East China Sea. By comparing with the observation data, the model results can reasonably capture the physical and biochemical dynamics of the Yangtze Estuary. In addition, the sensitive experiments were also used to examine the role of physical forcing (river discharge, wind speed, wind direction) in controlling hypoxia in waters adjacent to the Yangtze Estuary. The results showed that the wind field and river discharge have significant impact on the hypoxia off the Yangtze Estuary. The seasonal cycle of hypoxia was relatively insensitive to synoptic variability in the river discharge, but integrated hypoxic areas were sensitive to the whole magnitude of river discharge. Increasing the river discharge was shown to increase hypoxic areas, while decreasing the river discharge tended to decrease hypoxic areas. The variations of wind speed and direction had a great impact on the integrated hypoxic areas.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

  7. Antibiotics pollution in Jiulong River estuary: source, distribution and bacterial resistance.

    Science.gov (United States)

    Zheng, Senlin; Qiu, Xiaoyan; Chen, Bin; Yu, Xingguang; Liu, Zhenghua; Zhong, Guopei; Li, Hengyang; Chen, Meng; Sun, Guangda; Huang, Hao; Yu, Weiwei; Freestone, David

    2011-09-01

    To gain insight into the antibiotic pollution in the Jiulong River estuary and the pollutant sources, we analyzed the concentration of 22 widely-used antibiotics in water samples collected from the river and estuary, 17 and 18 sampling sites, respectively. Contamination with sulfonamides, quinolones and chloramphenicols was frequently detected and the distribution pattern of antibiotics suggested that most of the pollutants are from the Jiulong River, especially from the downstream watersheds. To reveal the ecological effects, we isolated 35 bacterial strains from the estuary and analyzed their antibiotic resistance to the eight most frequently detected antibiotics. The bacteria were subsequently classified into seven different genera by 16SrDNA sequencing. Up to 97.1% of the bacteria showed resistance and 70.6% of strains showed multi-resistance to these antibiotics, especially to sulfonamides. This study demonstrated a pattern of antibiotic contamination in the Jiulong River and its estuary and illustrated high bacterial antibiotic resistance which was significantly correlated with the average antibiotics concentrations and detected frequencies in the estuary.

  8. 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)

    Science.gov (United States)

    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.

  9. River discharge contribution to sea-level rise in the Yangtze River Estuary, China

    Science.gov (United States)

    Kuang, Cuiping; Chen, Wei; Gu, Jie; Su, Tsung-Chow; Song, Hongling; Ma, Yue; Dong, Zhichao

    2017-02-01

    Sea level changes in the Yangtze River Estuary (YRE) as a result of river discharge are investigated based on the monthly averaged river discharge from 1950 to 2011 at the Datong station. Quantification of the sea level contribution is made by model computed results and the sea level rates reported by the China Sea Level Bulletin (CSLB). The coastal modeling tool, MIKE21, is used to establish a depth-averaged hydrodynamic model covering the YRE and Hangzhou Bay. The model is validated with the measured data. Multi-year monthly river discharges are statistically calculated based on the monthly river discharges at Datong station from 1950 to 2011. The four characteristic discharges (frequency of 75%, 50% and 25%, and multi-year monthly) and month-averaged river discharge from 1950 to 2011 are used to study the seasonal and long-term changes of sea level. The computed sea level at the Dajishan and Lvsi stations are used to study the multi-time scale structure of periodic variation in different time scale of river discharge series. The results reveal that (1) the sea level rises as the river discharge increases, and its amplification decreases from upstream to the offshore. (2) The sea level amplification on the south coast is greater than that on the north coast. When river discharge increases by 20,000 m3/s, the sea level will increase by 0.005-0.010 m in most of Hangzhou Bay. (3) The sea level at the Dajishan station, influenced by river discharge, increased 0.178 mm/y from 1980 to 2011. Correspondingly, the sea level rose at a rate of 2.6-3.0 mm/y during the same period. These values were provided by the CSLB. The increase in sea level (1980-2011) at the Dajishan station caused by river discharge is 6.8-8.9% of the total increase in sea level. (4) The 19-20 year dominant nodal cycle of sea level at the Dajishan and Lvsi stations is in accord with 18.6 year nodal cycle of main tidal constituents on Chinese coasts. It implies that the sea-level change period on the

  10. Concentrations of suspended particulate organic carbon in the tidal Yorkshire Ouse River and Humber Estuary.

    Science.gov (United States)

    Uncles, R J; Frickers, P E; Easton, A E; Griffiths, M L; Harris, C; Howland, R J; King, R S; Morris, A W; Plummer, D H; Tappin, A D

    2000-05-05

    Data are presented for particulate organic carbon (POC) and particulate nitrogen (PN) concentrations in the Humber Estuary and tidal River Ouse Estuary. The POC data were derived from approximately monthly surveys and are consistent with data reported for suspended particulate matter (SPM) in the non-tidal River Ouse (the freshwater river) and with SPM, or bed sediments, in estuarine ecosystems such as the Mississippi, Delaware, San Francisco Bay, Tolo Harbour, the Vellar Estuary and Cochin Backwater, as well as the Loire, Gironde, Ems and Tamar Estuaries. Relative to the dry weight of SPM, the Humber-averaged organic carbon and nitrogen percentages during the year February 1995-March 1996 were 2.6 +/- 0.6% (mean and S.D.) and 0.21 +/- 0.04%, respectively. The ratio of Humber-averaged POC to Humber-averaged PN was 13 +/- 3. Higher POC levels were observed near the Humber's mouth and in the adjacent coastal zone during 'bloom' conditions, and in the upper estuarine reaches during large, winter and springtime freshwater inflows. At these times of high runoff, the POC content of SPM increased progressively up-estuary from the coastal zone to the tidal River Ouse. When inflows became very low, during late spring to early autumn of 1995, both the freshwater-saltwater interface (FSI) and the strengthening turbidity maximum (TM) moved further up-estuary and the POC content of SPM in the upper reaches of the Ouse became lower compared with that immediately down-estuary. This led to a poorly defined POC maximum near the confluence of the Humber, Ouse and Trent, before POC eventually decreased again towards the coastal zone. The lower POC contents in the upper estuarine reaches of the tidal Ouse may have been partly due to POC respiration by heterotrophic bacteria attached to SPM within the TM, consistent with the severe oxygen depletion observed there during high turbidity, summertime spring tides.

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

    Science.gov (United States)

    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.

  12. Nutrient characterisation of river inflow into the estuaries of the ...

    African Journals Online (AJOL)

    2014-10-02

    Oct 2, 2014 ... The Gwaing and Hartenbos estuaries would be most vulnerable to increased nutrient .... nutrient concentrations (for the entire time series), were used to ...... temporal dynamics of phytoplankton and microphytobenthos in a.

  13. Improving navigability on the Kromme River Estuary: A choice ...

    African Journals Online (AJOL)

    2013-03-14

    Mar 14, 2013 ... ƒk represents the density distribution functions associated with each .... regulation. Let jet skis and wet bikes use the estuary, but in a regulated manner with ... intercept survey selection strategy was adopted where every nth.

  14. Decadal changes in bathymetry of the Yangtze River Estuary: Human impacts and potential saltwater intrusion

    Science.gov (United States)

    Wu, Shuaihu; Cheng, Heqin; Xu, Y. Jun; Li, Jiufa; Zheng, Shuwei

    2016-12-01

    This study analyzed bathymetric changes of the 77-km Yangtze River Estuary in China over the past ten years in order to understand the impacts of recent human activities on the estuary of a large alluvial river. Morphological changes were assessed by analyzing digitized bathymetric data of the estuarine channels from 2002 to 2013. Additionally, multi-beam bathymetric measurements made in 2012, 2014 and 2015 were utilized to investigate microtophographic bedforms of the lower reach of the estuary. Our results showed that the middle and upper reaches of the Yangtze River Estuary experienced substantial channel bed erosion in the past 10 years, and that the recent human activities have contributed to the change. These included the construction of a 70 km2 reservoir along the Yangtze River Estuary, the Qingcaosha Reservoir, for drinking water supply for the City of Shanghai, which has caused progressive bed erosion in the North Channel. The net volume of channel erosion in the Hengsha Passage from 2002 to 2013 was 0.86 × 108 m3. A large amount of the eroded sediment was trapped downstream, causing overall accretion in the upper reach of the North Passage. The middle and upper reaches of the South Passage also experienced intense erosion (0.45 × 108 m3) in the past ten years, while high accretion occurred in the lower reach because of the Deepening Waterway Project. The channel dredging left a large range of dredging marks and hollows in the North Passage. The increasing saltwater intrusion found in the Yangtze River Estuary may have been a consequence of either dredging or erosion, or both combined.

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

    Science.gov (United States)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    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. 78 FR 23746 - Takes of Marine Mammals Incidental to Specified Activities; Russian River Estuary Management...

    Science.gov (United States)

    2013-04-22

    ... would facilitate formation of a perched lagoon, which will reduce flooding while maintaining appropriate..., dilapidated jetty on the formation and maintenance of the Russian River estuary, as required under RPA 2 of... operators, three safety team members on the beach (one on each side of the channel observing the...

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

    Science.gov (United States)

    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...

  19. Cultivation Of Eucheuma Cottoni In Various Planting Distance From The River Estuary

    Directory of Open Access Journals (Sweden)

    Patang

    2015-08-01

    Full Text Available This study aimed to know the effect of various distances from the estuary of the river in the cultivation of seaweed Eucheuma cottoni on growth and production. The research was conducted using the method of research used experimental method to completely randomized design CRD. The treatments were tested namely cultivation of seaweed with a distance of 450 station I and 900 m from estuary of the river station II with initial weight of each bond seaweed of 200 g Connective with a repeat 3 times. The data collected is data growth production and water quality. Data were analyzed with descriptive analysis. The results showed the growth and production of seaweed Eucheuma cottoni that tested higher obtained in the treatment of 450 m from the estuary of the river compared with the treatment of 900 m from estuary of the river that is thought to be caused due to water quality and better suited to the needs of seaweed especially salinity and phosphate

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  1. The Bot River, a closed estuary in the south-western Cape

    African Journals Online (AJOL)

    The salinity at the time of survey ranged from 7 - 1il/00, ... The Bot River vlei is a large, closed estuary situated between ... zooplankton as well as temperature and oxygen fluctuations ... Benthic invertebrates were sampled from a series of five.

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

    Science.gov (United States)

    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...

  3. Impact of river discharge on phytoplankton bloom dynamics in eutrophic estuaries: A model study

    NARCIS (Netherlands)

    Liu, B.; de Swart, H.E.

    2015-01-01

    Field observations in estuaries reveal that phytoplankton blooms are strongly affected by advection processes related to river flow. To gain quantitative insight into this dependence, experiments were performed with a new idealised model that couples physical and biological processes. Advection of p

  4. Investigating phenology of larval fishes in St. Louis River estuary shallow water habitats

    Science.gov (United States)

    As part of the development of an early detection monitoring strategy for non-native fishes, larval fish surveys have been conducted since 2012 in the St. Louis River estuary. Survey data demonstrates there is considerable variability in fish abundance and species assemblages acro...

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

    Science.gov (United States)

    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) ...

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

    Science.gov (United States)

    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...

  7. Hydrology of the Upper Malad River basin, southeastern Idaho

    Science.gov (United States)

    Pluhowski, Edward J.

    1970-01-01

    The report area comprises 485 square miles in the Basin and Range physiographic province. It includes most of eastern' Oneida County and parts of Franklin, Bannock, and Power Counties of southeastern Idaho. Relief is about 5,000 feet; the floor of the Malad Valley is at an average altitude of about 4,400 feet. Agriculture is, by far, ,the principal economic .activity. In 1960 the population of the upper Malad River basin was about 3,600, of which about 60 percent resided in Malad City, the county seat of Oneida County. The climate is semiarid throughout the Malad Valley and its principal tributary valleys; ,above 6,500 feet the climate is subhumid. Annual precipitation ranges from about 13 inches in the lower Malad Valley to more than 30 inches on the highest peaks of the Bannock and Malad ranges. Owing to ,the normally clear atmospheric conditions, large daily and seasonal temperature fluctuations are common. Topography, distance from the Pacific Ocean, .and the general atmospheric circulation are the principal factors governing the climate of the Malad River basin. The westerlies transport moisture from the P.acific Ocean toward southeastern Idaho. The north-south tren4ing mountains flanking the basin are oriented orthogonally to the moisture flux so that they are very effective in removing precipitable water from the air. A minimum uplift of 6,000 feet is required to transport moisture from the Pacific source region; accordingly, most air masses are desiccated long before they reach the Malad basin. Heaviest precipitation is generally associated with steep pressure gradients in the midtroposphere that are so oriented as to cause a deep landward penetration of moisture from the Pacific Ocean. Annual water yields in the project area range from about 0.8 inch in the, lower Malad Valley to more than 19 inches on the high peaks north and east of Malad City. The mean annual water yield for the entire basin is 4 inches, or about 115,000 acre-feet. Evaporation is

  8. Complex movement patterns of greenback flounder (Rhombosolea tapirina) in the Murray River estuary and Coorong, Australia

    Science.gov (United States)

    Earl, Jason; Fowler, Anthony J.; Ye, Qifeng; Dittmann, Sabine

    2017-04-01

    The greenback flounder Rhombosolea tapirina is a commercially-important flatfish species in southern Australia and New Zealand, whose population dynamics are poorly understood. Acoustic telemetry was used to assess movement patterns and area use for R. tapirina in the Murray River estuary and Coorong, South Australia. Twenty fish (221-313 mm total length) equipped with acoustic transmitters were monitored for up to seven months during a period of high freshwater inflow. Fish were detected over a large part of the system, but showed a strong preference for brackish and near-marine conditions in the inner estuary. Tagged fish exhibited complex movement patterns that differed among individuals, including: (1) within estuary movements; (2) dispersal from the estuary to the sea; and (3) return migrations between the estuary and the sea. A diurnal shift in fine-scale area use was observed in the part of the estuary where residency was highest, with individuals occupying deeper habitats during the day and shallower areas during the night. The results demonstrate the individualistic and often highly transient behaviour of this species and its ability to undertake regular movements over the spatial scale of 10s of km. Understanding such movement patterns can improve effective management of estuarine flatfish populations and ecosystems.

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

    Science.gov (United States)

    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.

  10. Fluxes of nitrogen in Chaliyar River Estuary, India

    Digital Repository Service at National Institute of Oceanography (India)

    Xavier, J.K.; Joseph, T.; Paimpillii, J.S.

    out the estuary in all seasons and so nitrogen is not a limiting nutrient for primary production. The urea-N fraction remains < 7% with the lowest levels in pre monsoon. The contribution of Ammonia-N to total nitrogen pool is < 10% during monsoon...

  11. Flushing characteristics of Amba river estuary, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    DineshKumar, P.K.; Sarma, R.V.; Josanto, V.

    of 22 tidal cycles for neap, 6 to 7 tidal cycles for spring and dry weather flushing time of 45 tidal cycles for neap, 6 to 7 tidal cycles for spring based on modified tidal prism method indicated that the load retained in the estuary after infinite...

  12. The Palmiet River estuary in the south-western Cape

    African Journals Online (AJOL)

    A further series of I £ water samples was taken in conjunc- tion with current .... Rough estimates of the dry biomass of zooplankton were obtained from three hauls ..... estuary are very much higher at times, ranging from < 2 to. 300 J.tg atoms N ...

  13. Physico-chemical investigations in Auranga river estuary (Gujarat)

    Digital Repository Service at National Institute of Oceanography (India)

    Zingde, M.D.; Sharma, P.; Sabnis, M.M.

    of pollutants and after a large number of tidal cycles was estimated to be less than 3 times the load introduced per tidal cycle. The suspended load in the estuary varied with the current speed and was mainly due to the dispersion of the bottom sediment...

  14. Biogeochemistry of Nutrient Elements in the Changjiang (Yangtze River) Estuary

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Based on the biogeochemical studies on nutrient elements in the Changjiang estuary,the main results and recent progresses are reviewed in this paper, such as the nutrient fluxes into the sea, the mixing behaviors, the distribution characteristics and transportation as well as the biogeochemical behaviors of nutrients in the plume frontal region. The exploring directions and research emphases in the future are proposed.

  15. The recreational value of river inflows into South African estuaries

    African Journals Online (AJOL)

    Expert opinions on the consequences of specified hypothetical changes to water inflows into ... to those estimated using an alternative valuation method (the contingent travel cost method), and ... nation's water resources, the Act has instituted the Reserve in .... required for the Kleinemonde West Estuary, leading to mean.

  16. A Modeling Study on Saltwater Intrusion to Western Four Watercourses in the Pearl River Estuary

    Institute of Scientific and Technical Information of China (English)

    CHENG Xiang-ju; ZHAN Wei; GUO Zhen-ren; YUAN Li-rong

    2012-01-01

    Saltwater intrusion has been serious in the Pearl River estuary in recent years.For better understanding and analysis of the saltwater movement to the estuary,the three-dimensional Finite-Volume Coastal Ocean Model (FVCOM) is made to simulate the salinity intrusion to the four western watercourses in the Pearl River estuary under three semilunar conditions.With the measured and simulated Root Mean Square Error (RMSE) and the mean absolute percentage error of water level and salinity at multiple sites,the results show that the numerical water levels,salinity and flow velocities are in agreement with the measured data.It is acceptable and feasible to apply the FVCOM to simulate the salt water intrusion in the western four watercourses of the Pearl River.With the numerical data,the time and spatial movement patterns of saltwater intrusion along the Modao watercourse are analyzed.The salinity contour reaches its peak generally during 3~5 days before the spring tide.The salinity stratification is more obvious in the period of ebb tide than that in the rising tide whether in the spring or neap tides.Salt fluxes reflect changes of salt into the estuary,and the change rules are close to the rules of salinity intrusion.

  17. Distribution and partition of polybrominated diphenyl ethers (PBDEs) in water of the Zhujiang River Estuary

    Institute of Scientific and Technical Information of China (English)

    LUO XiaoJun; YU Mei; MAI BiXian; CHEN ShenJun

    2008-01-01

    The spatial, temporal, and vertical distributions of polybrominated diphenyl ethers (PBDEs) in water columns from the Zhujiang River Estuary were examined, and the partition behavior of PBDEs between particle and dissolved phases was investigated in the present study. The results show that the distributions of PBDEs concentrations in the water varied with the sampling seasons. The PBDEs concentrations in water samples were lower in May 2005, when the brackish water was dominant in the estuary, than in October 2005, when fresh water from river runoff dominated the estuary. The spatial distribution of PBDEs in October 2005 indicated that the river runoff was the major mode to input PBDEs to the estuary, and the concentration of PBDEs in water might be dissolved organic carbon (DOC) dependence. The spatial and vertical distributions of PBDEs in May 2005 were relatively homogeneous, and SPM was the major factor on controlling the levels of PBDEs in this sampling time. Both DOC and POC could play certain roles in determining the distribution and partition of PBDEs between particle and dissolved phases, but their effects varied with the water properties.

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

    Science.gov (United States)

    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.

  19. BED VARIATION ANALYSIS IN THE CHIKUGO RIVER ESTUARY BY THE FLOOD FLOWS

    Science.gov (United States)

    Suzuki, Kenta; Shimamoto, Hisanori; Kubo, Seiki; Fukuoka, Shoji

    A series of fisherie issues in the Ariake sea has been believed to be caused by a lack of sand supply from the Chikugo river on the basis of few investigations of characteristics and amount of sediment transport in the the Chikugo river estuary. The core sampling and super-sonic echo sounder indicates that the vertical structure of mid stream of the Chikugo river estuary is consists of complex alternate layer and the rate of water content is much different to each layer. To make the rate of sand transport in the Chikugo river estuary clear, the authors applied unsteady quasi-three dimensional flood flow and river bed variation analysis using observed temporal changes in water surface profiles of flood. In the analysis, the bed layer which the rate of water content upper than 70% is calculated 2009by the experimental equation of erosion speed of the cohesive material. The results of analysis indicates that the rate of sand supply is strongly affected by the tidal level change of the Ariake sea.

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

    Science.gov (United States)

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

    2007-01-01

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

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

    Science.gov (United States)

    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 (stress to young planted pines on tree farms within the watershed.The Florida Geological Survey/US 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. The data are intended to provide a benchmark for comparison with metal concentration data measurements. Seventy nine short cores were collected from 66 sample locations

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

    Science.gov (United States)

    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. Fire history of southeastern Glacier National Park: Missouri River Drainage

    Science.gov (United States)

    Barrett, Stephen W.

    1993-01-01

    information existed for GNP's east-side forests, which are dominated primarily by lodgepole pine. In fall 1992, the park initiated a study to determine the fire history of the Missouri River drainage portion of southeastern GNP. Given the known variation in pre-1900 fire patterns for lodgepole pine, this study was seen as a potentially important contribution to GNP's Fire Management Plan, and to the expanding data base of fire history studies in the region. Resource managers sought this information to assist their development of appropriate fire management strategies for the east-side forests, and the fire history data also would be a useful interactive component of the park's Geographic Information System (GIS). Primary objectives were to: 1) determine pre-1900 fire periodicities, severities, burning patterns, and post-fire succession for major forest types, and 2) document and map the forest age class mosaic, reflecting the history of stand replacing fires at the landscape level of analysis. Secondary objectives were to interpret the possible effects of modern fire suppression on area forests, and to determine fire regime patterns relative to other lodgepole pine ecosystems in the Northern Rockies.

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

    Science.gov (United States)

    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.

  5. FA07005_LOGBOOK.PDF: Acquistion Log in PDF Format Maintained on USGS Cruise 07005 in the Corsica River Estuary

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Submarine groundwater discharge (SGD) into Maryland's Corsica River Estuary was investigated as part of a larger study to determine the importance of nutrient...

  6. Processed Continuous Resistivity Profile Data Collected in the Corsica River Estuary, Maryland on May 16, 2007 on USGS Cruise 07005

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Submarine groundwater discharge (SGD) into Maryland's Corsica River Estuary was investigated as part of a larger study to determine the importance of nutrient...

  7. Processed Continuous Resistivity Profile Data Collected in the Corsica River Estuary, Maryland on May 17, 2007 on USGS Cruise 07005

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Submarine groundwater discharge (SGD) into Maryland's Corsica River Estuary was investigated as part of a larger study to determine the importance of nutrient...

  8. Processed Continuous Resistivity Profile Data Collected in the Corsica River Estuary, Maryland on May 15, 2007 on USGS Cruise 07005

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Submarine groundwater discharge (SGD) into Maryland's Corsica River Estuary was investigated as part of a larger study to determine the importance of nutrient...

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

    Energy Technology Data Exchange (ETDEWEB)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    Bottom, Daniel L.; Simenstad, Charles A.; Campbell, Lance [Northwest Fisheries Science Center

    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

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

    Directory of Open Access Journals (Sweden)

    G Curtis Roegner

    Full Text Available 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Science.gov (United States)

    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

  14. Nitrification and inorganic nitrogen distribution in a large perturbed river/estuarine system: the Pearl River Estuary, China

    Directory of Open Access Journals (Sweden)

    Minhan Dai

    2008-04-01

    Full Text Available We investigated the spatial distribution and seasonal variation of dissolved inorganic nitrogen in a large perturbed estuary, the Pearl River Estuary, based on three cruises conducted in winter (January 2005, summer (August 2005 and spring (March 2006. On-site incubation was also carried out for determining ammonium and nitrite oxidation rates (nitrification rates. We observed a year-round pattern of dramatic decrease in NH4+, increase in NO3 but insignificant change in NO2 in the upper estuary at salinity ~0–5. However, species and concentrations of inorganic nitrogen at estuary significantly changed with season. In winter with low runoff the most upper reach of the Pearl River Estuary showed relatively low rates of ammonia oxidation (0–5.4 μmol N L−1 d−1 and nitrite oxidation (0–5.2 μmol N L−1 d−1, accompanied by extremely high concentrations of ammonia (up to >800 μmol L−1 and nitrate (up to >300 μmol L−1. In summer, the upper estuary showed higher nitrification rates (ammonia oxidation rate ~1.5–33.1 μmol N L−1 d−1, nitrite oxidation rate ~0.6–32.0 μmol N L−1 d−1 with lower concentrations of ammonia (<350 μmol L−1 and nitrate (<120 μmol L−1. The Most Probable Number test showed relatively lower nitrifier abundance in summer at most sampling stations, indicating a greater specific nitrification rate per cell in the warm season. Temperatures appeared to control nitrification rates to a large degree in different seasons. In addition to aerobic respiration, nitrification contributed significantly to the consumption of dissolved oxygen (DO and production of CO2 at the upper estuary. Nitrification-induced DO consumption accounted for approximately up to one third of the total water column

  15. Distribution and ecotoxicological significance of polycyclic aromatic hydrocarbons in sediments from Iko River estuary mangrove ecosystem.

    Science.gov (United States)

    Essien, Joseph P; Eduok, Samuel I; Eduok, Stephen I; Olajire, Abass Abiola

    2011-05-01

    The distribution of polycyclic aromatic hydrocarbons (PAHs) in epipelic and benthic sediments from Iko River estuary mangrove ecosystem has been investigated. Total PAHs ranged from 6.10 to 35.27 mg/kg dry weight. Quantitative difference between the total PAHs in epipelic and benthic sediments showed that the benthic sediment known for higher capability to serve as sink for chemical pollutants accumulated less PAHs. This implies that PAHs in the epipelic sediment may plausibly be from industrial sources via runoff and/or of biogenic origin. A strong pyrolytic source fingerprint has been detected with slight influence of petrogenic sources. Total organic carbon normalized PAHs (sum of 16 PAHs, 59.7 to 372.4 mg/kg OC) were under (except for ES3 and BS3) the threshold effects concentrations (TEC, 290 mg/kg OC). Total PAHs in Iko River estuary sediments were in the range between ERL and ERM.

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

    Science.gov (United States)

    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).

  17. Morphodynamic processes of the Elbe River estuary, Germany: the Coriolis effect, tidal asymmetry and human dredging

    Science.gov (United States)

    Li, Maotian; Ge, Jianzhong; Kappenberg, Jens; Much, Dagmar; Nino, Ohle; Chen, Zhongyuan

    2014-06-01

    The Digital Elevation Model (DEM) based on the historical sea-charts and on-site hydrological records were used to examine the morphological change of the Elbe River estuary. The results show that siltation predominated in the tidal flat in the northern estuary, with a net siltation rate of 1.8 cm·a-1 during 1927-2006. In contrast, a continuous erosion prevailed in the main river channel, south of the estuary, with a net erosion rate of 2.5 cm·a-1 in the same time. In addition, a seaward shift of the estuarine island has happened with the old island coalescing to the northern tidal flat and new one emerging through siltation process. The tidal asymmetry via ebbing flow (maximum at 140 cm·s-1, and average at 76 cm·s-1) prevailed in the tidal flat, meaning continuous aggradation northwestward, while flooding flow (maximum at 100 cm ·s-1, and average at 67 cm·s-1) dominated in the main river channel with deepening thaweg at south, showing a landward sedimentation via the tidal pumping processes. This dextral extension of the estuarine morphology is due to the Coriolis force, leading to the inconsistent directions of in-out flows, which enables to facilitate the estuarine siltation. Human dredging prevailing in the estuary has dramatically altered the nature of the silted river channel to erosional since the last century. This is characterized by a net erosion rate of 3.2 cm·a-1 derived from the DEMs mapping, but only partially accounting for the dredging amount of 1994-2006, when the total dredging volume was 67 × 106 m3, equal to 5.9 cm·a-1.

  18. Analysis on the Circulation of the Yangtze River Estuary Based on ADCP Measurements

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    According to analysis on field data obtained by ADCP (Acoustic Doppler Current Profiler), the flow regime of the Yangtze River Estuary is studied by use of a 3-D numerical model. The flow field characteristics, under the influence of Coriolis force, saltwater intrusion and freshwater inflow and tidal current interaction, are depicted in details. The main driving forces and some important effective factors of lateral, longitudinal and horizontal circulation are also analyzed.

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

    Energy Technology Data Exchange (ETDEWEB)

    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).

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-03-22

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Borde, Amy B. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kaufmann, Ronald M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Cullinan, Valerie I. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Zimmerman, Shon A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Thom, Ronald M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wright, Cynthia L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2012-03-01

    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.

  2. Estimation of Peak Water Level in Pearl River Estuary under the Background of Sea Level Rise

    Institute of Scientific and Technical Information of China (English)

    KONG; Lan; CHEN; Xiao-hong; ZHUANG; Cheng-bin; CHEN; Dong-wei

    2012-01-01

    [Objective] The study aimed to predict the peak water level in Pearl River Estuary under the background of sea level rise. [Method] The changing trends of peak water level at Denglongshan station and Hengmen station were analyzed firstly on the basis of regression models, and then sea level rise in Pearl River Estuary in 2050 was predicted to estimate the 1-in-50-year peak water level in the same year. [Result] Regression analyses showed that the increasing rate of peak water level over past years was 6.3 mm/a at Denglongshan station and 5.8 mm/a at Hengmen station. In addition, if sea level will rise by 20, 30 and 60 cm respectively in 2050, it was predicted that the 1-in-50-year peak water level will reach 3.04, 3.14 and 3.44 m at Denglongshan station, and 3.19, 3.29 and 3.59 m at Hengmen station separately. [Conclusion] The estimation of peak water level in Pearl River Estuary could provide theoretical references for water resources planning.

  3. Variation of reactivity of particulate and sedimentary organic matter along the Zhujiang River Estuary

    Institute of Scientific and Technical Information of China (English)

    Chen Jianfang; Jin Haiyan; Yin Kedong; Li Yan

    2003-01-01

    To investigate organic matter source and reactivity in the Zhujiang River (Pearl River)Estuary and its adjacent areas, particulate organic carbon (POC), particulate hydrolysable amino acids (PHAA), and Chl a during two cruises in July 1999 and July 2000 were measured. The highest POC and PHAA concentration was observed in the waters with maximum Chl a. The spectra distribution,relative content (dry weight in milligram per gram), PHAA-C% POC and other indicators such as the ratios of amino acids vs. amino sugars (AA/AS) and glucosamine vs. galactosamine (Glum/Gal) suggested that particulate amino acids in the water column and sediments in the Zhujiang River Estuary were mainly derived from biogenic processes rather than transported from terrestrial erosion. In inner estuary where high turbidity was often observable, organic matter was mainly contributed by re-suspension of bottom sediments with revealed zooplankton, microbial reworked characteristics, which suggest that these organic matters were relatively "old". In the estuarine brackish region, organic matter in water column is mainly contributed by relatively fresh, easily degradable phytoplankton derived organic matter.During physical - biological processes within the eastuary, organic matter derived from phytoplankton was subjected to alteration by zooplankton grazing and bacterial reworking.

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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

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

    Science.gov (United States)

    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

  7. Evaluation of geochemical behavior and heavy metal distribution of sediments:The case study of the Tirumalairajan river estuary, southeast coast of India

    Institute of Scientific and Technical Information of China (English)

    Senapathi VENKATRAMANAN; Sang-yong CHUNG; Thirunavukkarasu RAMKUMAR; Tae Hyung KIM

    2015-01-01

    The purpose of this study was to assess the chemical partitioning of selected heavy metals (Fe, Mn, Cu, Zn, Pb, Cr, Co and Ni) in 10 surface sediments at Tirumalairajan River Estuary in the southeastern coast of India. A five-step sequential extraction technique was used to assess the environmental status of heavy metals. Most of metals were considered to be immobile due to the high availability in the residual fraction of heavy metals. The sediments of Tirumalairajan River estuary had not been polluted by heavy metals, and they didn’t pose any high ecological risk. The seasonal variations of heavy metals were slightly higher in summer than in monsoon season. Factor analysis was also carried out to understand the associations of metals in different fractions with sand, silt, clay, organic matter, pH, salinity and other metals. The relationship between the Q-mode and R-mode cluster analyses was useful for identifying the pollution levels in both seasons. It was proved that the enrichment of heavy metals was related with geogenic and anthropogenic sources. The information on total metal concentrations in sediments was not sufficient for assessing the metal behavior in the environment, but the sequential extraction technique was more effective in estimating the environmental impact of contaminated sediments.

  8. Changes in Huanghe (Yellow) River estuary since artificial re-routing in 1996

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    With the combination of historical data, field observations and satellite remotely sensed images (Landsat TM/ETM+ and CBERS), changes in Huanghe (Yellow) River estuary since 1996 when artificial Chahe distributary was built up were studied, mainly including water and sediment discharge from the river, tides, tidal currents, suspended sediment diffusion, coastline changes and seabed development. During following six and half years (up to the end of 2002), runoff and sediment loads into the river mouth declined dramatically. At the beginning of the re-routing, abundant sediment loads from the river filled up nearshore shallow water areas so that the newborn delta prograded quickly. With rapid decrease of sediment loads transported to the estuary, the delta retrograded. In 1997, subaerial tip of the abandoned delta receded 1.5km; its annual mean recession rate was about 150 m in following years. In addition, marine dynamic condition near the artificial outlet had also changed. Under the interaction of ocean and river flow, most of incoming sediment loads deposited in the vicinity of the outlet. Seabed erosion occurred at the subaqueous delta front. Between 1999 and 2002, erosion thickness averaged at 0.3 m in the subaqueous delta of 585.5 km2.

  9. Holocene and modern sediment storage in the subtropical macrotidal Fitzroy River estuary, Southeast Queensland, Australia

    Science.gov (United States)

    Bostock, Helen C.; Brooke, Brendan P.; Ryan, David A.; Hancock, Gary; Pietsch, Tim; Packett, Robert; Harle, Kate

    2007-10-01

    The Fitzroy River estuary is a macrotidal, tide-dominated estuary located in the dry tropics of central Queensland, and represents the major source of terrestrial sediment to the southern Great Barrier Reef (GBR) lagoon. The estuary currently receives most of its sediment during large episodic floods that are typically associated with cyclones. Mean annual sediment budgets for such systems are difficult to estimate due to the sporadic nature of flood discharge events, which are highly seasonal and vary greatly in magnitude between years. We have estimated the quantity and long-term rate of accumulation of catchment-derived sediment in the estuarine floodplain using the Holocene stratigraphic sequence determined from a series of sediment cores, dated with radiocarbon and optically stimulated luminescence (OSL) methods. Approximately 13,760 million tonnes (Mt) of fluvial sediment has accumulated in the Fitzroy estuary during the past 8000 years, which equates to an average of 1720 kt yr - 1 . Over the past 100 years, sediment accumulation has been focused around mangrove and tidal creek environments, which cover an area of 130 km 2. Cores from the tidal creeks, dated using 137Cs, 210Pb, and OSL, provide sedimentation rates of approximately 15 mm yr - 1 for the past 45-120 years, or sediment mass accumulation of 1700 kt yr - 1 , which includes a component that is reworked into the estuary by tidal currents. Combined with the small amount of sediment that accumulates on the floodplain during floods (˜ 1 mm yr - 1 , 640 kt yr - 1 ), we estimate that approximately 2350 kt yr - 1 of sediment is trapped in the modern lower floodplain and estuary. This estimate of sediment storage suggests that greater than 50% of the modern mean annual sediment discharge of the Fitzroy River, 4162 kt yr - 1 , may be retained in the lower floodplain and estuary. These results provide useful insights into the spatial pattern of sedimentation, long-term rates of accumulation and estimates of

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  13. Nutrients and carbon fluxes in the estuaries of major rivers flowing into the tropical Atlantic

    Directory of Open Access Journals (Sweden)

    Moacyr Cunha De Araujo

    2014-05-01

    Full Text Available Knowledge of the seasonal variability of river discharge and the concentration of nutrients in the estuary waters of large rivers flowing into the tropical Atlantic contributes to a better understanding of the biogeochemical processes that occur in adjacent coastal and ocean systems. The monthly averaged variations of the physical and biogeochemical contributions of the Orinoco, Amazon, São Francisco, Paraíba do Sul (South America, Volta, Niger and Congo (Africa Rivers are estimated from models or observations. The results indicate that these rivers deliver approximately 0.1 Pg C yr-1 in its dissolved organic (DOC 0.046 Pg C yr-1 and inorganic (DIC 0.053 Pg C yr-1 forms combined. These values represent 27.3% of the global DOC and 13.2% of the global DIC delivered by rivers into the world’s oceans. Estimations of the air-sea CO2 fluxes indicate a slightly higher atmospheric liberation for the African systems compared with the South American estuaries (+10.67 mmol m-2 day-1 and +5.48 mmol m-2 day-1, respectively. During the high river discharge periods, the fluxes remained positive in all of the analyzed systems (average +128 mmol m-2 day-1, except at the mouth of the Orinoco River, which continued to act as a sink for CO2. During the periods of low river discharges, the mean CO2 efflux decreased to +5.29 mmol m-2 day-1. The updated and detailed review presented here contributes to the accurate quantification of CO2 input into the atmosphere and to ongoing studies on the oceanic modeling of biogeochemical cycles in the tropical Atlantic.

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

    Directory of Open Access Journals (Sweden)

    Naishun Bu

    Full Text Available 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.

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

    Science.gov (United States)

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

    2017-03-01

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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 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.

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

    Science.gov (United States)

    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. Nitrate sources and dynamics in the salinized rivers and estuaries – a δ15N- and δ18O-NO3– isotope approach

    Directory of Open Access Journals (Sweden)

    D. Xue

    2014-03-01

    Full Text Available To trace NO3– sources and assess NO3– dynamics in the salinized rivers and estuaries, three rivers (HH River, CB River and JY River and two estuaries (HH Estuary and CJ Estuary along the Bohai Bay (China have been selected to determine DIN and δ15N and δ18O-NO3–. Upstream of the HH River NO3– was removed 30.9 ± 22.1% by aerobic denitrification, resulting from effects of the floodgate: limiting water exchange with downstream and prolonging water residence time to remove NO3–. Downstream of the HH River NO3– was removed 2.5 ± 13.3% by NO3– turnover processes. Conversely, NO3– was increased 36.6 ± 25.2% by external N source addition in the CB River and 34.6 ± 35.1% by in-stream nitrification in the JY River, respectively. The HH and CY Estuaries behaved mostly conservative excluding the sewage input in the CJ Estuary. Hydrodynamics in estuaries have been changed by the ongoing reclamation projects, aggravating the estuaries losing the attenuation function of NO3–.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

  2. A Coupled Model of the 1D River Network and 3D Estuary Based on Hydrodynamics and Suspended Sediment Simulation

    Directory of Open Access Journals (Sweden)

    Wei Zhang

    2014-01-01

    Full Text Available River networks and estuaries are very common in coastal areas. Runoff from the upper stream interacts with tidal current from open sea in these two systems, leading to a complex hydrodynamics process. Therefore, it is necessary to consider the two systems as a whole to study the flow and suspended sediment transport. Firstly, a 1D model is established in the Pearl River network and a 3D model is applied in its estuary. As sufficient mass exchanges between the river network and its estuary, a strict mathematical relationship of water level at the interfaces can be adopted to couple the 1D model with the 3D model. By doing so, the coupled model does not need to have common nested grids. The river network exchanges the suspended sediment with its estuary by adding the continuity conditions at the interfaces. The coupled model is, respectively, calibrated in the dry season and the wet season. The results demonstrate that the coupled model works excellently in simulating water level and discharge. Although there are more errors in simulating suspended sediment concentration due to some reasons, the coupled model is still good enough to evaluate the suspended sediment transport in river network and estuary systems.

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

    Energy Technology Data Exchange (ETDEWEB)

    Hamzah, Zaini, E-mail: tengkuliana88@gmail.com; Rosli, Tengku Nurliana Tuan Mohd, E-mail: tengkuliana88@gmail.com; Saat, Ahmad, E-mail: tengkuliana88@gmail.com; Wood, Ab. Khalik, E-mail: tengkuliana88@gmail.com [Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor (Malaysia)

    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.

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

    Science.gov (United States)

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

    2001-09-01

    Fish were sampled in nearshore, shallow waters (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 fish community in winter contrasts with the gradual, cyclical changes undergone during the year by the ichthyofaunas of holarctic, macrotidal estuaries, such as the Severn Estuary in the UK, in which the hydrology does not undergo such sudden, extreme seasonal changes and the ichthyofauna is dominated by marine and diadromous species that each enter the estuary at specific, but varying times of the year. Differences between the fish faunas of the shallow waters of the Swan and

  5. Assessment of heavy metal pollution in surficial sediments from a tropical river-estuary-shelf system: A case study of Kelantan River, Malaysia.

    Science.gov (United States)

    Wang, Ai-Jun; Bong, Chui Wei; Xu, Yong-Hang; Hassan, Meor Hakif Amir; Ye, Xiang; Bakar, Ahmad Farid Abu; Li, Yun-Hai; Lai, Zhi-Kun; Xu, Jiang; Loh, Kar Hoe

    2017-08-11

    To understand the source-to-sink of pollutants in the Kelantan River estuary and the adjacent shelf area in Malaysia, a total of 42 surface sediment samples were collected in the Kelantan River-estuary-shelf system to analyze for grain size, total organic carbon (TOC) content, Al and heavy metals (Cr, Ni, Cu, Zn, Cd and Pb). The surficial sediments were mainly composed of clayey silt and the TOC content in sediments decreased from the river to the shelf. The surficial sediments experienced Pb pollution; Cr only showed a certain level of pollution in the coastal area of the estuary but not in other areas, and Ni, Cu, Zn, and Cd showed no pollution. The heavy metals mainly originated from natural weathering and erosion of rocks and soils in the catchment and enriched near the river mouth. Total organic carbon can promote the enrichment of heavy metals in sediments. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. The morphology and morphodynamics of sand-gravel subaquatic dunes: the Raba River estuary, Poland

    Directory of Open Access Journals (Sweden)

    Artur RADECKI-PAWLIK

    2012-08-01

    Full Text Available In the outlet of the Raba River to the Vistula, the biggest river in Poland, the morphology and morphodynamics of sand and fine-gravel subaquatic dunes were investigated. The site is situated in highland region just about the entrance to Polish Carpathians. The dunes formed on the Raba River bed estuary are composed of sand and fine gravel (d50 up to 11 mm. Systematic observation (within the 2000-2005 were made of geometry, sediment composition and hydraulic climate under which the dunes grew and decomposed. The investigation focuses here mostly on the geometrical parameters of these bed forms such as height, length, as well as granulometric characteristics of the sediment. Based on in-site measurements different hydraulic parameters were calculated such as shear stresses, resistant coefficient, Froude and Reynolds numbers and roughness coefficient. It was found that the relation between height (H and length (L of the Raba estuary dunes describes the formula: H = 0.05L0.35. Also these dunes are steeper and flatter then classical H/L index is: H/L = 0.0518L0.622. During the field campaign, when the foot access to the estuary was possible and dunes were spotted on the river bed the range of measured water velocity was from v = 0.39 m∙s-1 to v = 0.81 m∙s-1 with the highest velocity over the dune crest. At the same time the measured range of shear stresses within the dune field formation were from t = 0.115 N×m-2 to t = 1.59 N×m-2. On the field investigations the CCHE2D - two-dimensional unsteady flow and sediment transport model for non-equilibrium transport of non-uniform sediment mixtures – was applied. The model was used to simulate the morphodynamic changes along the outlet of the Raba River basing on field observations of the 2005 summer flood as well as calculate hydraulics parameters. It was also used to test and confirm the range of morphodynamic changes, which take place along the research reach where the dunes are being developed

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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

  10. Water quality model with multiform of N/P transport and transformation in the Yangtze River Estuary

    Institute of Scientific and Technical Information of China (English)

    王彪; 卢士强; 林卫青; 杨漪帆; 王道增

    2016-01-01

    As the Yangtze River Estuary and adjacent sea have been classified as a problem area with regard to eutrophication, it is important to explore the spatial and temporal variations of nitrogen and phosphorus (N/P) nutrients in this area. Based on danish hydraulic institute (DHI)’s open platform Ecolab, a hydrodynamic and water quality model was developed for the Yangtze River Estuary, in which the transport and transformation processes of different forms of N/P nutrients were considered. Validations against measured data show that the model is overall reliable. Preliminary application of the model suggests that the model can simulate the characteristics of high phosphorus concentration area in the Yangtze River Estuary, and the high concentration area is closely related to the resuspension process of particulate phosphorus.

  11. Selenium in the upper Blackfoot River watershed, southeastern Idaho, 2001-12

    Science.gov (United States)

    Mebane, Christopher A.; Mladenka, Greg; Van Every, Lynn; Williams, Marshall L.; Hardy, Mark A.; Garbarino, John R.

    2014-11-05

    The upper Blackfoot River in southeastern Idaho receives runoff from 12 large phosphate mines. Waste shales that are removed to access the phosphate ore are highly enriched with selenium, resulting in elevated selenium in runoff from the mine waste dumps. In 2001, in cooperation with the Bureau of Land Management, the U.S. Geological Survey (USGS) began monitoring streamflow, selenium, and other water-quality parameters at a single location near the outlet of the upper Blackfoot River to the Blackfoot Reservoir. Water samples primarily were collected by a flow triggered, automated pump sampler, supplemented by manual point and equal-width integrated manual samples.

  12. Chromium in water, suspended particles, sediments and biota in the Iraja River estuary

    Energy Technology Data Exchange (ETDEWEB)

    Pfeiffer, W.C.; Fiszman, M.; de Lacerda, L.D.; van Weerfelt, M.; Carbonell, N.

    1982-11-01

    Analyses of chromium concentrations in waters, suspended particles, bottom sediments, fish (Poecilia reticulata), plants (Paspalum vaginatum, Sesuvium portulacastrum, Philoxeros vermicularis), soils and barnacles (Balanus sp.) were performed from August 1976 to September 1980 in samples collected from the Iraja River and inside its estuary in Guanabara Bay (Rio de Janeiro, Brazil). Sediments and water from the Iraja River showed chromium concentrations of 17536 and 23.39 ppm--a thousand times higher than the published data for freshwater systems. Chromium removed from solution by bottom sediments reaches Guanabara Bay linked to particulate matter. Fish and emergent grass inside the river concentrate chromium from water and/or sediment, returning the metal to the system as detritus. Soil and plants inside the estuary concentrate chromium thirty and ten times higher than in the control area. The vegetal community exhibits a concentration factor smaller than that related to soil and prevents the return of chromium to the estuarine waters. Inside the Guanabara Bay, Balanus sp. appears to be an effective biological monitor as it concentrates chromium in soft tissues 10/sup 3/ times higher than values found in suspended particles (0.012 ..mu..g ml/sup -1/).

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

    Science.gov (United States)

    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.

  14. Historical records of eutrophication in Changjiang (Yangtze River estuary and its adjacent East China Sea

    Directory of Open Access Journals (Sweden)

    F. Cheng

    2012-06-01

    Full Text Available Two sediment cores from the Changjiang (Yangtze River estuary and its adjacent East China Sea were collected and studied for eutrophication history using paleoecological records of environmental changes over the last century. A multiproxy approach by using biological and geochemical analyses revealed changes in diatom assemblages, total organic carbon (TOC, total nitrogen (TN and biogenic silica (BSi and give an indication of nutrient in status and trends in Changjiang River estuary and its adjacent East China Sea. The diatom assemblages in the two cores generally increased gradually from the 1970s, and accelerated from the 1990s until now, reflecting the increased eutrophication and causing large algae blooms/red tides. The TOC, TN and BSi showing the similar trends, supported the interpretation of the eutrophication process indicated by diatom analyses. The two cores were located in different sea areas of the East China Sea, and we discuss their relative changes based on their environment characteristics. We also discuss the potential effect of anthropogenic influences and ongoing projects on eutrophication in the Changjiang River and its adjacent East China Sea.

  15. 18O and 226Ra in the Minjiang River estuary, China and their hydrological implications

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  19. Nitrogen Source Apportionment for the Catchment, Estuary, and Adjacent Coastal Waters of the River Scheldt

    Directory of Open Access Journals (Sweden)

    Jan E. Vermaat

    2012-06-01

    Full Text Available Using the systems approach framework (SAF, a coupled model suite was developed for simulating land-use decision making in response to nutrient abatement costs and water and nutrient fluxes in the hydrological network of the Scheldt River, and nutrient fluxes in the estuary and adjacent coastal sea. The purpose was to assess the efficiency of different long-term water quality improvement measures in current and future climate and societal settings, targeting nitrogen (N load reduction. The spatial-dynamic model suite consists of two dynamically linked modules: PCRaster is used for the drainage network and is combined with ExtendSim modules for farming decision making and estuarine N dispersal. Model predictions of annual mean flow and total N concentrations compared well with data available for river and estuary (r² ≥ 0.83. Source apportionment was carried out to societal sectors and administrative regions; both households and agriculture are the major sources of N, with the regions of Flanders and Wallonia contributing most. Load reductions by different measures implemented in the model were comparable (~75% remaining after 30 yr, but costs differed greatly. Increasing domestic sewage connectivity was more effective, at comparatively low cost (47% remaining. The two climate scenarios did not lead to major differences in load compared with the business-as-usual scenario (~88% remaining. Thus, this spatially explicit model of water flow and N fluxes in the Scheldt catchment can be used to compare different long-term policy options for N load reduction to river, estuary, and receiving sea in terms of their effectiveness, cost, and optimal location of implementation.

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

    Science.gov (United States)

    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

  1. Detection of estuarine and tidal river hydromorphology using hyper-spectral and LiDAR data: Forth estuary, Scotland

    Science.gov (United States)

    Gilvear, David; Tyler, Andrew; Davids, Corine

    2004-11-01

    High spatial resolution hyper-spectral imagery (CASI) and light detection and ranging (LiDAR) imagery acquired for the tidal River Carron and Forth estuary, Scotland, were used in conjunction with field surveys to assess the feasibility of monitoring hydromorphology and human alterations with satellite and airborne remote sensing data. The study was undertaken in the context of the European Union Water Framework Directive (WFD) that requires member states to monitor hydromorphological elements as a component of the ecological status of rivers, estuaries and shorelines. Visual assessment and automated classifications of the imagery were compared with field survey data for an estuarine reach comprising saline waters, mudflats, a tidal reach of a tributary river and an urban/industrialised shoreline. The morphology of the estuary and inflowing tidal waters together with most artificial features of interest could be clearly seen in the CASI imagery at 1 m spatial resolution. Supervised classification of the imagery produced an overall accuracy value of 72%. Downgrading the imagery to simulate the spatial resolution of 4 m IKONOS satellite data surprisingly improved the accuracy to 74%. Simulation of 10 m SPOT imagery resulted in an image where many artificial features of interest such as roads, pipelines and jetties were rendered invisible. Adding LiDAR data as an additional data set aided manual and automated identification of features and visualisation of the hydromorphology of the rivers and estuaries in the study area. Shadows cast from tall objects were a feature of the winter imagery and reduced automated classification accuracy. Overall, the study demonstrates that high spatial resolution remotely sensed digital imagery has the potential to be a useful tool for panoptic mapping of the geomorphology and human impact on tidal rivers and estuaries. In the context of the WFD, remote sensing provides a potential way forward for monitoring the physical status of

  2. Assessment of water quality of a river-dominated estuary with hydrochemical parameters: A statistical approach.

    Digital Repository Service at National Institute of Oceanography (India)

    Padma, P.; Sheela, V.S.; Suryakumari, S.; Jayalakshmy, K.V.; Nair, S.M.; Kumar, N.C.

    stream_size 64084 stream_content_type text/plain stream_name Water_Qual_Expos_Health_5_197.pdf.txt stream_source_info Water_Qual_Expos_Health_5_197.pdf.txt Content-Encoding UTF-8 Content-Type text/plain; charset=UTF-8... Water Qual Expo Health DOI 10.1007/s12403-014-0115-9 ORIGINAL PAPER Assessment of Water Quality of a River-Dominated Estuary with Hydrochemical Parameters: A Statistical Approach P. Padma · V. S. Sheela · S. Suryakumari · K. V. Jayalakshmy · S. M. Nair...

  3. Drivers of sulfide intrusion in Zostera muelleri in a moderately affected estuary in south-eastern Australia

    DEFF Research Database (Denmark)

    Holmer, Marianne; Bennett, William W.; Ferguson, Angus J. P.

    2017-01-01

    The seagrass Zostera muelleri Irmisch ex Asch. is abundant in estuaries in Australia and is under pressure from coastal developments. We studied sulfide intrusion in Z. muelleri along a gradient of anthropogenic impact at five stations in the Wallis Lake estuary, Australia. Results showed...

  4. The energy budget under the influence of topography in the Zhujiang River Estuary in China

    Institute of Scientific and Technical Information of China (English)

    LIU Huan; WU Chaoyu; WU Yaju

    2015-01-01

    The Zhujiang River (Pearl River) Estuary (ZRE) is a very complicated and large-scale estuarine system in China. It consists of two parts: the river networks and the estuarine bays. Not only is the network system one of the most complicated in the world, but also each estuarine bay has a very special morphodynamic feature due to the geological settings. Morphological boundary conditions have direct effects on the energy dissipa-tion and balance. On the basis of a three-dimensional (3-D) barotropic model whose domain includes the river networks and the estuarine bays, the energy budget is discussed under the influence of topography in the ZRE. The elevation and discharge of this model are validated by the observations collected in July 1999 and February 2001. The results show that (1) the source of energy in the ZRE is mainly generated by tides and river runoffs, which have an obvious seasonal change, and (2) there are some typical hotspots where the energy dissipation is 1–2 orders higher than those in the immediate upstream and downstream sections in the ZRE. These hotspots are linked with the small-scale dynamic structures (SSDS) and morphological units. On the basis of the characteristics of the morphology and the energy dissipation, the hotspots can be catego-rized into three types: the outlet of the ZRE, the meandering river, the branch and junction.

  5. Effect of large-scale reservoir and river regulation/reclamation on saltwater intrusion in Qiantang Estuary

    Institute of Scientific and Technical Information of China (English)

    韩曾萃; 潘存鸿; 余炯; 程杭平

    2001-01-01

    By using field salinity data recorded in the Qiantang Estuary for the nearly forty years (which covers the periods before and after the erection of a large-scale reservoir in the watershed and river regulation/reclamation in the estuary) and one-dimensional salt water intrusion modeling, it is shown that the salt water intrusion decreases caused by increased low water discharge for the reservoir, while the intrusion increases for the increased tidal range because of the river regulation/reclamation. The integrate result is that the saltwater intrusion decreases.

  6. Comparison of biogenic methane emissions from unmanaged estuaries, lakes, oceans, rivers and wetlands

    Science.gov (United States)

    Ortiz-Llorente, M. J.; Alvarez-Cobelas, M.

    2012-11-01

    A literature review of quantitative data was carried out to conduct a cross-system study on methane emissions relating peak emissions (PE) and annual emissions (AE) in five types of non-managed ecosystems: estuaries, lakes, oceans, streams and wetlands. PE spanned eight orders of magnitude (0.015 μg CH4 m-2 h-1-300 mg CH4 m-2 h-1) while AE spanned seven (0.078-19044 g CH4 m-2 yr-1). PE and AE were strongly related worldwide (r2 = 0.93). There was no relationship between AE and latitude, with highly variable PE across latitudes and climates. The coefficient of variation (CV) was greatest for emissions in oceans and estuaries, while the highest emission rate was recorded in wetlands and lakes. Efflux from coastal areas and estuaries was higher than that from upwelling areas and deep seas. Concerning wetland types, marshes showed the highest PE with the highest wetland emissions occurring in sites dominated by big helophytes. Non-stratifying- and eutrophic lakes displayed more emissions than other lake types, but there was no environmental variable that might predict methane emissions from lakes on a worldwide basis. Generally, most ecosystem types followed a seasonal pattern of emissions, with a maximum in summer, except in estuaries which did not show any distinct pattern. Regarding the importance of hot spots within most ecosystems, more spatial variability of CH4 emissions was observed in lakes than in wetlands and oceans; however, no relationship between emissions and spatial variability was found. A positive relationship, albeit weak, was found between methane flux and either temperature or irradiance in wetlands; a narrow range of both negative and positive values of the water table promoted CH4 emissions. Previously, little was known about the factors controlling efflux from river and marine environments. Our study suggests that local conditions are important in controlling CH4 emissions, because the variability explained by the more commonly studied abiotic

  7. Phytoplankton pigments and functional community structure in relation to environmental factors in the Pearl River Estuary

    Directory of Open Access Journals (Sweden)

    Chao Chai

    2016-07-01

    Full Text Available Two cruises were undertaken in the Pearl River Estuary in November 2011 and March 2012 to analyze the distribution of phytoplankton pigments and to define the relationships of pigment indices and functional community structure with environmental factors. Among 22 pigments, 17 were detected by high-performance liquid chromatography. Chlorophyll a was found in all samples, with a maximum of 7.712 μg L−1 in spring. Fucoxanthin was the most abundant accessory pigment, with mean concentrations of 2.914 μg L−1 and 0.207 μg L−1 in spring and autumn, respectively. Chlorophyll a, chlorophyll c2, fucoxanthin, diadinoxanthin, and diatoxanthin were high in the northern or northwest estuary in spring and in the middle-eastern and northeast estuary in autumn. Chlorophyll b, chlorophyll c3, prasinoxanthin, and peridinin were similarly distributed during the two cruises. Chlorophyll a and fucoxanthin positively correlated with nutrients in spring, whereas 19′-hex-fucoxanthin and 19′-but-fucoxanthin negatively correlated. The biomass proportion of microphytoplankton (BPm was higher in spring, whereas that of picophytoplankton (BPp was higher in autumn. BPm in spring was high in areas with salinity 30. BPm increased but BPn reduced with the increase in nutrient contents. By comparison, BPp reduced with the increase in nutrient contents in spring, but no relationship was found between BPp and nutrient contents in autumn. The ratios of photosynthetic carotenoids to photoprotective carotenoids in the southern estuary approached unity linear relationship in spring and were under the unity line in autumn.

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

    Science.gov (United States)

    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.

  9. 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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  10. Maixi River estuary to the Baihua Reservoir in the Maotiao River catchment: phytoplankton community and environmental factors

    Institute of Scientific and Technical Information of China (English)

    LI Qiuhua; CHEN Lili; CHEN Fengfeng; GAO Tingjin; LI Xiaofeng; LIU Songping; LI Cunxiong

    2013-01-01

    Phytoplankton and environmental variables were measured monthly from July 2009 to August 2011 in the Maixi River from the estuary to Baihua Reservoir in the Maotiao River catchment,southwestern China,to understand phytoplankton community structure and environmental factors.The relationship between phytoplankton community structure and environmental factors including hydrological,meteorological,physical,and chemical variables were explored using multivariate analysis.A total of 81taxa of phytoplankton were identified,which were mainly composed of chlorophyta,bacillariophyta,and cyanobacteria.The phytoplankton community was dominated by Pseudanabaena limnetica during summer and fall and by Cyclotella meneghiniana during winter and spring.The abundance of phytoplankton ranged from 0.24×104 cells/L to 33.45×i06 cells/L,with the minimum occurring during February 2010 and the maximum during July 2009.The phytoplankton community was dominated mainly by cyanobacteria from April to September,and by bacillariophyta and pyrrophyta from October to March.Canonical correspondence analysis showed that temperature,pH values,and orthophosphate were the most important driving factors regulating the composition and dynamics of the phytoplankton community in the estuary.Cyanobacteria and euglenophyta abundance and biomass were affected mainly by temperature and pH values,while most chlorophyta and bacillariophyta were influenced by the concentrations of nutrients.

  11. Preliminary study on the dissolved oxygen distributions and the influential factors in the Daliao River estuary and its adjacent areas

    Institute of Scientific and Technical Information of China (English)

    LEI Kun; MENG Wei; ZHENG Binghui; FU Guo

    2004-01-01

    Dissolved oxygen (DO) concentrations were surveyed in the Daliao River Estuary in autumn to investigate the temporaland spatial trends of DO distributions. The results indicate that DO is weakly stratified in the Yingkou section of theDaliao River Estuary, and remains constant vertically in the areas near and out of the entrance. Horizontally, both in-stantaneous and continuous observations show that the Yingkou section of the Daliao River Estuary is affected by hy-poxic conditions; while no conditions of low DO have been observed in the areas near and out of the entrance.DO-salinity correlations exhibit different controlling factors of DO distributions in different sections of the Daliao Riv-er Estuary. At the upstream part of the Yingkou section of the Daliao River (A1-A4), oxygen demanding materials and the associated biochemical processes are the main factor controlling the DO distribution, but in the lower part of theYingkou section and the area near and out of the entrance (A5-A15), tidal advections are more influential for DO distributions.

  12. Dynamics of circulation and salt balance in the upper reaches of Periyar river estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Varma, P.U.; Pylee, A.; Sankaranarayanan, V.N.

    The Eulerian residual currents of the upper reaches of Periyar estuary (Kerala, India) were directed down the estuary throughout the water column during the monsoon season. During the summer months the residual flow was directed up the estuary...

  13. A numerical experiment on tidal river simplification in simulation of tide dominated estuaries

    Science.gov (United States)

    Yin, X.; Jia, L.; Zhu, L.

    2017-04-01

    In numerical simulation of tide dominated estuaries, introduction of simplified tidal channels into the model for real rivers is one of the strategies to deal with the lack of topographic data. To understand the effects of simplification and their sensitivity to the simplifying parameters, a numerical experiment was conducted to test the parameters such as channel length L, surface width B, bed slope S, bottom elevation ▽0, bed roughness n and run-off Qr. The results indicated the values of those parameters which were liable to less tidal prism and greater flood resistance would result in larger simulation errors. For a better simplification the values of parameters for the channel geometry, resistance and upstream inflow needed to be consistent with the average of the natural river as much as possible. The simplification method made the computation stable, fast and saved the storage space and it was adoptable for different time periods and seasons.

  14. A REVIEW OF HEAVY METAL POLLUTION IN THE PEARL RIVER ESTUARY

    Institute of Scientific and Technical Information of China (English)

    HUANG Sui-liang; ONYX W. H. Wai

    2004-01-01

    Since 70's, the economy and society in the Pearl River Delta region have been undergoing a great development. Pollution control and environment protection have received much public attention. As heavy metals are an important toxic pollutant source in this area and are not biodegradable in general, a lot of scientists in China, especially in Southern China, devote their focus on studying the pollution caused by heavy metals in the Pearl River Estuary (PRE). This paper presents a comprehensive review on the heavy metal pollution research and its related research in this area. It is suggested that the study of heavy metal pollution in PRE should be coupled with water movement, sediment motion and tidal characteristics in this region. Studying core sediments in various locations is recommended to reveal the history of heavy metal pollution in PRE and improve the understanding of the fate and transport of metals.

  15. Ship Emission Inventories in Estuary of the Yangtze River Using Terrestrial AIS Data

    Directory of Open Access Journals (Sweden)

    Xin Yao

    2016-12-01

    Full Text Available Estuary forms a transition zone between inland river and open sea. In China, the estuary of the Yangtze River plays a vital role in connecting the inland and oversea shipping, and witnesses heavy vessel traffic in the recent decades. Nowadays, more attentions have been directed to the issue of ship pollution in busy waterways. In order to investigate the ship emission inventory, this paper presents an Automatic Identification System(AIS based method. AIS data is the realistic data of vessel traffic including dynamic information (position, speed, course, etc. and static information (ship type, dimensions, name, etc.. According to ship dimensions, the power of engines is estimated for different ship types. By using AIS based bottom-up approach, ship emission inventories and shares of air pollutants and GHGs (Greenhouse gases are developed. Spatial distribution of ship emissions is illustrated in the form of heat map. As a case study, the emission inventories are analyzed using AIS data of 2010 in the estuary, and following results are made:(1 shares of the emission are cruise ships 6.59%, bulk carriers 5.16%, container ships 52.96%, tankers 15.16%, fishing ships 9.16%, other ships 10.97%; (2 CO2 is the dominant part of the emission. (3 Areas of highest emission intensity are generally clustered around the South Channel, the North Channel and ports in the vicinity. The proposed method is promising because it is derived from the AIS data which contains not only real data of individual ship but also vessel traffic situation in the study area. It can server as a reference for other researchers and policy makers working in this field.

  16. Spatial distribution and quantification of endocrine-disrupting chemicals in Sado River estuary, Portugal.

    Science.gov (United States)

    Ribeiro, Cláudia; Pardal, Miguel Angelo; Tiritan, Maria Elizabeth; Rocha, Eduardo; Margalho, Rui Miguel; Rocha, Maria João

    2009-12-01

    The important Portuguese Sado River estuary has never been investigated for the presence of potentially endocrine-disrupting chemicals (EDCs), such as natural estrogens (estradiol, estrone), pharmaceutical estrogens (17alpha-ethynylestradiol), phytoestrogens (daidzein, genistein and biochanin A), or industrial chemicals (4-octylphenol, 4-nonylphenol, and bisphenol A). Thus, the main objective of this study was to evaluate their presence at 13 sampling points distributed between both the industrial and the natural reserve areas of the estuary, zones 1 and 2, respectively. For that, water samples collected in summer and winter were processed by solid phase extraction and analyzed by high-performance liquid chromatography with photodiode array detection and gas chromatography-mass spectroscopy. Results showed that estrone, ethynylestradiol, all the aforementioned phytoestrogens as well as bisphenol A and 4-octylphenol were found in zone 1. In zone 2, neither estrogens nor 4-OP were found. However, in the same zone, daidzein (500 ng/L) and genistein (320 ng/L) attained their highest levels in summer, whereas biochanin A peaked in winter (170 ng/L). Furthermore, bisphenol A was also found in some areas of zone 2, but showed similar concentrations in both surveys (about 220 ng/L). This study demonstrated that the Sado River estuary had low EDCs levels, suggesting that the Sado's high hydrodynamic activity may be involved in the dilution of local pollution. It was suggested that at the current levels of concentrations, all assayed EDCs are unlikely to individually cause endocrine disruption in local animals. However, under a continuous exposure scenario, an additive and/or synergistic action of the estrogenic chemicals load can not be excluded, and so, continuous monitoring is advisable.

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

    Science.gov (United States)

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

    2017-09-01

    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.

  18. Occurrence of PPCPs in Pearl River Estuary and South China Sea

    Science.gov (United States)

    Fisch, Kathrin; Waniek, Joanna J.; Schulz-Bull, Detlef E.

    2017-04-01

    The development of a coastal megacity has put the South China Sea under human induced stress. Pharmaceuticals and personal care products (PPCPs) are ubiquitous contaminants and can be used as anthropogenic indicators for pollution of the marine environment. They enter the marine environment indirectly via waste water or directly due to recreational activities. PPCPs make up a group of different pharmaceuticals such as antibiotic, anti-inflammatories etc. and personal care products such as UV-filters. A mayor concern is the unknown fate and the effect these pollutants on the marine environment and especially its organisms. In some studies it was proven that some of these PPCPs have an endocrine disrupting and/or a subtle chronic effect on aquatic organisms. They are of concern for the health of the marine environment and may have an effect on human health. With our study we could determine the occurrence of PPCPs in the Pearl River estuary and the South China Sea. Salicylic acid (metabolite of acetylsalicylic acid) and octocrylene (UV-filter) were found in the open Sea in low ng/L concentration. Octocrylene is used in sunscreen and as a light stabilizer in paints and polymer-based products. It is of environmental concern because of its potential to be bioaccumulative. In addition to our findings in the open South China Sea, could we detect PPCPs, especially antibiotics, in higher ng/L-concentrations in the Pearl River Estuary.

  19. Composition of fish communities in an intertidal salt marsh creek in the Changjiang River estuary, China

    Institute of Scientific and Technical Information of China (English)

    QUAN Weimin; NI Yong; SHI Liyan; CHEN Yaqu

    2009-01-01

    Fish communities in a (third-order) intertidal creek in Dongtan marsh in the Changjiang (Yangtze) River estuary were investigated seasonally for one year. A total of 1 996 fish specimens (10 967.8 g) comprising 26 species and 15 families were collected. Abundances of fish communities in the intertidal salt marsh creek were primarily dominated by Boleophthalmus pectinirostris (19.8%), Collichthys lucidus (18.6%), Periophthalmus magnuspinnatus (18.2%), Liza haematocheilus (17.9%), and secondarily by Mugilogobius abei (8.5%), L. carinatus (7.2%), Odontamblyopus lacepedii (4.3%), and Acanthogobius ommaturus (3.9%); another 18 species were present only occasionally. Non-MDS ordination and SIMPER analysis indicated that there were two fish communities in the intertidal salt marsh creek. In spring, the communities were dominated by B. pectinirostris, P. magnuspinnatus, C. lucidus and M. abei; in summer, autumn, and winter by L. haematocheilus, L. carinatus, A. ommaturus and O. lacepedii. Some species showed strong habitat selection; L. carinatus and P. magnuspinnatus were distributed mainly in the upper and middle creek, while B. pectinirostris, M. abei and O. lacepedii inhabited the middle and lower creek. The study indicated that the salt marshes of the Changjiang River estuary are an important nursery and feeding habitat for many fishes and should be protected.

  20. Stakeholder perceptions of ecosystem services of the Wami River and Estuary

    Directory of Open Access Journals (Sweden)

    Catherine G. McNally

    2016-09-01

    Full Text Available Management of riverine and coastal ecosystems warrants enhanced understanding of how different stakeholders perceive and depend upon different kinds of ecosystem services. Employing a mixed methods approach, this study compares and contrasts the use and perceptions of upstream residents, downstream residents, tourism officials, and conservation organizations regarding the value of 30 ecosystem services provided by the Wami River and its estuary in Tanzania, and investigates their perceptions of the main threats to this system. Our findings reveal that all of the stakeholder groups place a high value on the provision of domestic water, habitat for wild plants and animals, tourism, and erosion control, and a relatively low value on the prevention of saltwater intrusion, refuge from predators, spiritual fulfillment, nonrecreational hunting, and the provision of traditional medications and inorganic materials for construction. Differences emerge, however, between the groups in the value assigned to the conservation of riverine and estuarine fauna and the provision of raw materials for building and handicrafts. Declining fish populations and an increasing human population are identified by the residents and conservation employees, respectively, as their prime concerns regarding the future conditions of the Wami River and its estuary. These groups also acknowledge increasing salinity levels and the loss of mangroves as other key concerns. The identification of these mutual interests and shared concerns can help build common ground among stakeholders while the recognition of potential tensions can assist managers in balancing and reconciling the multiple needs and values of these different groups.

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

    Energy Technology Data Exchange (ETDEWEB)

    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).

  2. PRELIMINARY STUDY ON THE DISSOLVED AND COLLOIDAL ORGANIC CARBON IN THE ZHUJIANG RIVER ESTUARY

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    This paper reports data on the dissolved and colloidal organic carbon in the Zhujiang (Pearl) River estuary. DOC concentration was 142 to 239 μmol/L in the freshwater taken in March 1997 from the four Zhujiang River tributaries flowing into the Lingdingyang estuary. High concentration was observed in the Humen tributary located near Guangzhou. The rapidly increased DOC concentration at low salinities (~5) may be attributed to the exchange between macroparticulate and dissolved organic matter during the early stage of estuarine mixing. DOC concentration overall followed the mixing line until salinity ~25, where the Deep Bay is located and where DOC was elevated. This elevated DOC may suggest a local organic matter source from Shenzhen. Using a cross-flow ultrafiltration (CFF) system equipped with a Millipore Prep-scale CFF 1 kD regenerated cellulose membrane, we also separated the colloidal organic matter from the truly dissolved fraction (<1 kD). CFF membranes were carefully evaluated for their applicability (retention characteristics, blank level and mass balance) to separate colloidal organic matter. COC in the study area ranged from 5 to 85 μmol/L, representing ~ 3%-32% of DOC. The highest COC percentage was found at low salinities (< 5) in both winter and summer. Evidence suggests in-situ production of colloidal material at this salinity range. Beyond this point, a very modest removal was observable until high salinities. Again, an increase in COC concentration was shown in the samples taken from the Deep Bay.

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

    Science.gov (United States)

    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.

  4. Change in the sedimentary environment of Wanquan River Estuary, Hainan Island,China

    Institute of Scientific and Technical Information of China (English)

    GE Chendong; O. Slaymaker; T. F. Pedersen

    2003-01-01

    210Pb geochronology and sediment core profiles of organic carbon, total sulfur and organic carbon isotope (δ 13C) values were used to reconstruct thelocal environmental history of the Shamei Lagoon, located in the Wanquan River Estuary, eastern Hainan Island, China. Total sulfur and δ 13C values decreased upwards in the top 30 cm of a sediment core that spanned the last 200 years of deposition. Total sulfur concentration and δ13C values respectively decreased upward from 1.92% to 0.36%, and -20.63‰ to -23.64‰. The C/S ratio in the 19th century and earlier was relatively stable in the range of 0.47-0.80, and there wasa positive correlation between organic carbon and total sulfur. Since around 1900 AD, the C/S ratio increased rapidly to a maximum of 3.94, but no simple correlation was found between organic carbon and total sulfur during this more recentperiod. These results indicated that before 1800 AD, the lagoon had a fully marine character, and the location of today's Wanquan River Estuary was an open embayment. From 1800 to 1900, the salinity of Shamei Lagoon decreased noticeably. The amount of seawater which could enter the lagoon decreased gradually as the Yudai spit grew. Today, seawater scarcely affects the lagoon; it is essentially a freshwater basin.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Bottom, Daniel L.; Simenstad, Charles A.; Campbell, Lance [Northwest Fisheries Science Center

    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

  8. Sediment Transport at River Lima Estuary: Developing a Sound Methodology to Assess Sediment River Basin Input to an Erosion Prone Coast (NW Iberian Peninsula)

    Science.gov (United States)

    Pinho, J.; Costa, N.; Venâncio, S.; Martins, M.; Vieira, J.; Granja, H.

    2016-12-01

    The NW coast of Iberian Peninsula is mainly formed by rocky cliffs northern of the river Minho mouth and by narrow sandy beaches south of this river. These beaches are mainly in a sedimentary deficit status resulting from the north-south longitudinal drift driven by the dominant wave climate that acts from the NW direction. In this scenario understand and quantify river sediment inputs to the coast is crucial in order to follow a sustainable management policy to mitigate erosion impacts both in the natural and social environments. This work will present results from research conducted at rive Lima Estuary, one of the rivers flowing to the NW Iberian coast, based on both numerical modeling and field data acquisition. A hydrological model of the river basin and a detailed morphodynamic model of the estuary were implemented. Instrumentation of the estuary that is being conducted comprises traditional sensor pressures and new ones that are being designed and assembled to be installed at different measurement stations within the estuary. Modelling results for flood events showed that the river is capable of remove all the sediments that are deposited in the narrow estuarine canal located near the river mouth. Some of these sediments are immediately deposited downstream, within the interior of the harbor. Here, there is a strong possibility of silting of the river mouth and the central area of the harbor. Since the river flows during extreme events are controlled by an upstream reservoir, the capacity of the river to transport sediments to the coast was lowered during the last decades, which, moreover, requires dredging works over the years to maintain navigation depth requirements. Dredging sediments should be correctly deposited at the coast in order to properly feed the longitudinal drift, otherwise they will be out of the system, which aggravate the installed erosion tendency.

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

    Science.gov (United States)

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

    2006-03-01

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

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

    Science.gov (United States)

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

  11. Place branding and endogenous rural development. Departure points for developing an inner brand for the River Minho estuary

    NARCIS (Netherlands)

    Dominguez Garcia, M.D.; Horlings, L.G.; Swagemakers, P.; Simón Fernández, X.

    2013-01-01

    Place branding holds a promising contribution to sustainable territorial development and requires changes in the social organisation of places, which implies complex transitional processes towards new management regimes. This article explores place branding of the River Minho estuary in the borderla

  12. Comparison of copper speciation in the Zhujiang River Estuary between summer and winter: implication for upwelling current

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The contents of total copper, total dissolved copper, particulate copper, and free ion copper in the Zhujiang River Estuary were investigated in July 2002 and January 2003 respectively, and the spatial distribution trend of these species of copper were compared in two cruises. It was found that, in summer, the total copper content in the Zhujiang River Estuary increased with salinity, while the content of free ion copper decreased with salinity. However, in winter, the contents of total copper and free ion copper both decreased with salinity. So, it could be concluded that, copper content and speciation in the Zhujiang River Estuary were regulated by other factors than runoffdiffusion such as upwelling current. In order to prove the spatial trend of free ion copper content in the Zhujiang River Estuary, the cultivation of Dunaliella tertiolecta in waters obtained from sampling stations with different salinities was carried out, and the copper uptake by algae cells was measured then. It was found that, the cells' uptake of copper increased with free ion copper, not the content of total copper.

  13. ENVIRONMENTAL STUDY OF THE SEASONAL SUCCESSION OF MESOZOOPLANKTON IN A BRACKISH WATER ODRA RIVER ESTUARY DURING 2003–2005

    Directory of Open Access Journals (Sweden)

    Juliusz C. Chojnacki

    2013-04-01

    Full Text Available The entire estuary water is dominated by the discharge of the River Odra into the Szczecin Lagoon. The water body is brackish and the salinity in the central part ranges 0.5 and 2 PSU. The Lagoon has a long eutrophication history; usually, two phytoplankton biomass peaks are observed: Diatoms in spring and blue-green algae in summer. The recent data on zooplankton is limited. Rotifers and Cladocerans supply the bulk of the zooplankton biomass. The ichtiofauna is composed of fresh and brackish water, migratory and marine species. Zooplankton and water samples were collected during 2003–2005. The results suggest that during 10 season’s climate in Odra River estuary, Cladocera were the dominant group, large impact on the density of mesozooplankton were: Daphnia cucullata and Daphnia longispina, Copepoda played a lesser role in the Odra River estuary than Cladocera. Biomass of mesozooplankton from the Lagoon was significantly higher compared with the biomass of mesozooplankton from Odra River estuary, which could be related to a greater inflow of nutrients into the Lagoon and the increased growth of phytoplankton, which forms an excellent first stage food web for herbivorous and carnivorous zooplankton, and fish and consequently cormorants.

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

    Institute of Scientific and Technical Information of China (English)

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

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

    Science.gov (United States)

    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...

  16. Surficial sediment distribution and the associated net sediment transport pattern in the Pearl River Estuary, South China

    NARCIS (Netherlands)

    Zhang, W.; Zheng, J.H.; Ji, X.M.; Hoitink, A.J.F.; van der Vegt, M.

    2013-01-01

    Spatial variations in grain-size parameters contain information on sediment transport patterns. Therefore, in this study, 106 surficial sediment samples taken from the Pearl River Estuary (PRE), South China, were analyzed, to better understand the net sediment transport pattern in this region. The P

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

    Science.gov (United States)

    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...

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

    Science.gov (United States)

    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.

  19. 76 FR 70480 - Otay River Estuary Restoration Project, South San Diego Bay Unit of the San Diego Bay National...

    Science.gov (United States)

    2011-11-14

    ... Fish and Wildlife Service Otay River Estuary Restoration Project, South San Diego Bay Unit of the San Diego Bay National Wildlife Refuge, California; Environmental Impact Statement AGENCY: Fish and Wildlife... the San Diego Bay National Wildlife Refuge. This notice advises the public that we intend to gather...

  20. SEFIDROOD RIVER SUB-WATERSHED-DAM-ESTUARY AND DEGRADATION MODEL: A HOLISTIC APPROACH IN IRAN

    Institute of Scientific and Technical Information of China (English)

    Forood AZARI DEHKORDI; Majid F MAKHDOUM; Nobukazu NAKAGOSHI

    2003-01-01

    The major concern of this article is to address the shortcoming and outgoing effects of the human activities on the landscape patterns and their consequences in the Sefidrood River watershed in Iran. A flow of data includes three inputs; each of them belongs to one part of three zones of a fluvial system. The three parts of the Sefidrood River fluvial system include Zone 1, a sub-watershed as degradation modeling site, Zone 2, Sefidrood Dam as dam site, and Zone 3, 17km away from the Sefidrood River path to the Caspian Sea as ending point site. The degradation model in the Zone 1 provides a suitable mean for decision support system to decrease the human impacts on each small district. The maximum number for degradation coefficient belongs to the small district with the highest physiographic density, relatively cumulative activities, and a lower figure for the habitat vulnerability. The human degradation impact were not limited to the upstream. The investigation to the Sefldrood Dam and ending point of the Sefldrood River depicts that sedimentation continues as a significant visual impact in the Sefidrood Dam reservoir and the estuary.

  1. Water Potential in Petanu River Estuary and Model of Water Resources Management for Sustainable Agriculture in Gianyar Regency Bali Province

    Directory of Open Access Journals (Sweden)

    Eryani I.GST AG PT

    2014-01-01

    Full Text Available Water needs in the province of Bali from year to year increase along with the rise of population and tourism activities. A study conducted by the Ministry of Environment (2009 stated that Bali is already experiencing water deficit during the dry seasons since 1995 as many as 1.5 billion m3 / year. To overcome this water deficit issue, it will require researching on the potential water resources in Bali. Along the Petanu River, there are 25 irrigation weirs on a 4475.5 ha of land. Research was carried out in in Saba village, Gianyar Regency, Bali, along The Petanu River up to its estuary. The data collected from the research included primary and secondary data, namely: water quality, water quantity (water volume in Petanu River estuary, precipitation, climate, and environmental conditions of the Petanu river. The data collected from the research site and the secondary data, the water quality was tested on the reseacrh site and  in the laboratory before it was analyzed. The model used to detect water presence (the water system along the Petanu River up to its estuary was procesed using a software called RIBASIM (River Basin Simulation. The result showed that there is a potential water source (water volume on the estuary of the Petanu River estuary during the dry season as much as 6.16 million m3 and during the rainy season as much as 43.79 million m3. Water quality in terms of physics (smell, taste, temperature, color, turbidity and salinity, meet the quality standards of class IV (for irrigation. Based on the simulation results on the RIBASIM software, the water resources in the Petanu River estuary can potentially be managed as irrigation water for horticulture agriculture along the coast of Saba. The potential water sources can be contained by building dams / reservoirs that are placed ± 300 m from the shoreline of Saba village in Gianyar regency. The water management model for the water sources in Petanu River to support sustainable

  2. Impact of seasonal tide variation on saltwater intrusion in the Changjiang River estuary

    Institute of Scientific and Technical Information of China (English)

    QIU Cheng; ZHU Jianrong; GU Yuliang

    2012-01-01

    An improved 3-D ECOM-si model was used to study the impact of seasonal tide variation on saltwater intrusion into the Changjiang River estuary,especially at the bifurcation of the North Branch (NB) and the South Branch (SB).The study assumes that the river discharge and wind are constant.The model successfully reproduced the saltwater intrusion.During spring tide,there is water and salt spillover (WSO and SSO) from the NB into the SB,and tidally averaged (net) water and salt fluxes are 985 m3/s and 24.8 ton/s,respectively.During neap tide,the WSO disappears and its net water flux is 122 m3/s.Meanwhile,the SSO continues,with net salt flux of 1.01 ton/s,much smaller than during spring tide.Because the tidal range during spring tide is smaller in June than in March,overall saltwater intrusion is weaker in June than in March during that tidal period.However,the WSO and SSO still exist in June.Net water and salt fluxes in that month are 622 m3/s and 15.35 ton/s,respectively,decreasing by 363 m3/s and 9.45 ton/s over those in March.Because tidal range during neap tide is greater in June than in March,saltwater intrusion in June is stronger than in March during that tidal period.The WSO and SSO appear in June,with net water and salt fluxes of 280 m3/s and 8.55 ton/s,respectively,increasing by 402 m3/s and 7.54 ton/s over those in March.Saltwater intrusion in the estuary is controlled by the river discharge,semi-diurnal flood-ebb tide,semi-monthly spring or neap tide,and seasonal tide variation.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  5. CO2 emissions from a temperate drowned river valley estuary adjacent to an emerging megacity (Sydney Harbour)

    Science.gov (United States)

    Tanner, E. L.; Mulhearn, P. J.; Eyre, B. D.

    2017-06-01

    The Sydney Harbour Estuary is a large drowned river valley adjacent to Sydney, a large urban metropolis on track to become a megacity; estimated to reach a population of 10 million by 2100. Monthly underway surveys of surface water pCO2 were undertaken along the main channel and tributaries, from January to December 2013. pCO2 showed substantial spatio-temporal variability in the narrow high residence time upper and mid sections of the estuary, with values reaching a maximum of 5650 μatm in the upper reaches and as low as 173 μatm in the mid estuary section, dominated by respiration and photosynthesis respectively. The large lower estuary displayed less variability in pCO2 with values ranging from 343 to 544 μatm controlled mainly by tidal pumping and temperature. Air-water CO2 emissions reached a maximum of 181 mmol C m-2 d-1 during spring in the eutrophic upper estuary. After a summer high rainfall event nutrient-stimulated biological pumping promoted a large uptake of CO2 transitioning the Sydney Harbour Estuary into a CO2 sink with a maximum uptake of rate of -10.6 mmol C m-2 d-1 in the mid-section of the estuary. Annually the Sydney Harbour Estuary was heterotrophic and a weak source of CO2 with an air-water emission rate of 1.2-5 mmol C m-2 d-1 (0.4-1.8 mol C m-2 y-1) resulting in a total carbon emission of around 930 tonnes per annum. CO2 emissions (weighted m3 s-1 of discharge per km2 of estuary surface area) from Sydney Harbour were an order of magnitude lower than other temperate large tectonic deltas, lagoons and engineered systems of China, India, Taiwan and Europe but were similar to other natural drowned river valley systems in the USA. Discharge per unit area appears to be a good predictor of CO2 emissions from estuaries of a similar climate and geomorphic class.

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

    Science.gov (United States)

    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.

  7. Study on Nutrient Limitation of Phytoplankton in the Field Experiment of the Yangtze River Estuary in Summer

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    From July 23rd to August 15th, 2001, a field cultivation experiment was carried out to determine the limitation factors of phytoplankton in the Yangtze River estuary and the adjacent areas. The results indicated that the potential limiting nutrient was phosphorus in the Yangtze River diluted water area, nitrogen in the offshore of the Yangtze River estuary and the conversion of phosphorus to nitrogen in the middle area. Iron and silicon were not the potential limiting factors. If there were some kinds of limiting factors in the water, the growth of phytoplankton would be limited obviously. In case of disappearance of the limiting factor, the phytoplankton would grow fast. When the Noctiluca scintiuans bloom occurred, the phytoplankton biomass level was very low in a short time due to the grazing pressure. When the grazing pressure disappeared, the phytoplankton would grow quickly in abundant nutrients condition.

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

    Science.gov (United States)

    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.

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

    KAUST Repository

    Fusi, Marco

    2016-07-07

    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. © 2016 Elsevier Ltd.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  11. THE BIOGEOCHEMISTRY OF PHOTOSYNTHETIC PIGMENTS IN THE JIULONG RIVER ESTUARY AND WESTERN XIAMEN BAY

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    High performance liquid chromatography (HPLC) analysis of photosynthetic pigments in samples from Western Xiamen Bay and the Jiulong River Estuary showed that their major carotenoids were fucoxanthin, peridinin, zeaxanthin, violaxanthin, and diadinoxanthin. Diatoms dominated in the spring bloom, dinoflagellates in summer. Violaxanthin and chlorophyll b indicated the appearance of chrysophytes and green algae, most of which were freshwater species. The high phytoplankton biomass region was located at the inner part of the bay. Diatoms and dinoflagellates dominated phytoplankton communities, contributing to over 50% of total biomass. All the main diagnostic carotenoids were significantly (P<0.01) correlated negatively to dissolved inorganic phosphorus, suggesting that they were limited by phosphorus. The high negative linear relationship (P<0.0001) between dissolved inorganic phosphorus and peridinin (dinoflagellates indicator) implied the potential of dissolved inorganic phosphorus for triggering red tide events in this region.

  12. THE BIOGEOCHEMISTRY OF PHOTOSYNTHETIC PIGMENTS IN THE JIULONG RIVER ESTUARY AND WESTERN XIAMEN BAY

    Institute of Scientific and Technical Information of China (English)

    徐立; 洪华生; 王海黎; 陈伟琪

    2001-01-01

    High performance liquid chromatography (HPLC) analysis of photosynthetic pigments in samples from Western Xiamen Bay and the Jiulong River Estuary showed that their major carotenoids were fucoxnnthin, peridinin, zeaxanthin, violaxanthin, and diadinoxnnthin. Diatoms dominated in the spring bloom, dinotlagellates in summer. Violaxanthin and chlorophyll b indicated the appearance of chrysophytes and green algae, most of which were freshwater species. The high phytoplankton biomass re-gion was located at the inner part of the bay. Diatoms and dinoilagellates dominated phytoplankton com-munities, contributing to over 50% of total biomass. All the main diagnostic carotenoids were significantly (P < 0.01 ) correlated negatively to dissolved inorganic phosphorus, suggesting that they were limited by phosphorus. The high negative linear relationship ( P < 0. 0001 ) between dissolved inorganic phosphorus and peridinin (dinoflagellates indicator) implied the potential of dissolved inorganic phosphorus for trig-gefing red tide events in this region.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  15. Tidal Hydrodynamics in the Lower Columbia River Estuary through Depth Averaged Adaptive Hydraulics Modeling

    Directory of Open Access Journals (Sweden)

    Gaurav Savant

    2014-01-01

    Full Text Available The adaptive hydraulics (AdH numerical code was applied to study tidal propagation in the Lower Columbia River (LCR estuary. The results demonstrate the readiness of this AdH model towards the further study of hydrodynamics in the LCR. The AdH model accurately replicated behavior of the tide as it propagated upstream into the LCR system. Results show that the MSf tidal component and the M4 overtidal component are generated in the middle LCR and contain a substantial amount of tidal energy. An analysis was performed to determine the causes of MSf tide amplification, and it was found that approximately 80% of the amplification occurs due to nonlinear interaction between the M2 and the S2 tidal components.

  16. Community characteristics of macrobenthos in the Huanghe (Yellow River) Estuary during water and sediment discharge regulation

    Institute of Scientific and Technical Information of China (English)

    REN Zhonghua; LI Fan; WEI Jiali; LI Shaowen; LV Zhenbo; GAO Yanjie; CONG Xuri

    2016-01-01

    The community characteristics of macrobenthos in the Huanghe (Yellow River) Estuary is influenced by a combination of natural and anthropogenic factors. Here, we investigated short-term changes (1-month) in macrobenthic community structure in response to water and sediment discharge regulation (WSDR) in 2011. Specifically, we sampled the macrobenthos at 18 sampling stations situated at four distances (5, 10, 20, and 40 km) from the mouth of the Huanghe Estuary before (mid-June), during (early-July), and after (mid-July) WSDR. The results showed that a total of 73, 72, and 85 species were collected before, during, and after WSDR, respectively. Then, 13, 1, and 16 dominant species were detected at this three periods. Four phyla were primarily detected at all three periods (Annelida, Mollusca, Arthropoda, and Echinodermata). However, while Mollusca and Annelida were the most important phyla in our study, Echinodermata and Annelida were the most important phyla in 1982, demonstrating major changes to community structure over a 3-decadal period. All stations were of high quality BOPA index before WSDR, whereas two and three stations were of reduced quality BOPA index during and after WSDR, respectively. The results of ABC curves showed that had incurred disturbed conditions after human activities WSDR. Most important of all, multivariate analyses and RDA analysis indicated that the structure of the macrobenthic community was closely linked to environment factors, including that organic content factor caused the distribution of macrobenthic community mostly during WSDR, while water depth after WSDR affected the macro benthos community structure seriously, and during WSDR, the environment factor influencing it was not single, including organic content, sulfide content, Hg and As. These differences may have been due to changes in water transparency negatively impacting the growth and development of macrobenthos, due to specific life-history requirements. Our results

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

    Science.gov (United States)

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

    2004-10-01

    Two cruises were conducted in the Pearl River Estuary (PRE) and adjacent coastal waters during July 1999 and 2000 to investigate spatial variation, transformation and degradation of amino acids (AAs). Salinity, suspended sediments (SS), chl a, nutrients, dissolved organic carbon, particulate organic carbon, AAs, and hexosamines were measured and analyzed. Concentrations of particulate hydrolysable AAs (PHAAs), dissolved combined AAs and dissolved free AAs ranged from 0.41 to 12.6 μmol L-1, 1.1 to 4.0 μmol L-1 and 0.15 to 1.10 μmol L-1, respectively. AAs concentrations were low in waters of salinity coincided with the region of the chl a maximum and depletion of dissolved inorganic phosphorus in the coastal plume south of Hong Kong. This indicates that most of the AAs in estuarine and coastal waters were produced through phytoplankton production and AAs might be a temporary sink for inorganic nitrogen. The ratios of AAs/HAs and glucosamine/galactosamine (Glc-NH2/Gal-NH2) were on average, 26.0 and 3.8, respectively, in biogenic particulate matter (chl a >5 μg L-1 and SS20 mg L-1) and reached the lowest values of 5.8 and 1.4 in sediments. In particular, the ratios of AAs/HAs, Glc-NH2/Gal-NH2 were low in the upper or northwest side of the estuary where turbidity was high. This indicated that these AAs were "old", likely due to resuspension of refractory organic matter from sediments or zooplankton grazing modification and bacterial reworking as the salt wedge advanced upstream near the bottom. Apparently, the dynamics of AAs in the PRE appeared to be governed by biological production processes and estuarine circulation in the estuary. As the chl a maximum developed downstream in the estuarine and coastal plume and the salt wedge moved upstream at the bottom, AAs increased and were subjected to sinking as particulates, grazing by zooplankton and reworking by bacterial activity. Sinking AAs would be transformed and modified in the lower layer, which would be brought

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

  20. Flow and salinity characteristics of the upper Suwannee River Estuary, Florida

    Science.gov (United States)

    Tillis, Gina M.

    2000-01-01

    Continuous stage and salinity data were recorded from August 1995 to December 1997 at four gages located in the upper Suwannee River Estuary. Continuous velocity data were recorded at two of the four gages and continuous discharge data were computed for these two gages. Additional salinity data were collected at 15 monitoring sites from November 1992 to October 1997. Wind-speed data collected at Cedar Key, Florida, during the study period were utilized in the regression analysis. Correlations were developed to describe the longitudinal extent of the saltwater/freshwater interface (defined as 0.5 parts per thousand (ppt) salinity) and salinity distribution in the upper Suwannee River Estuary. On East Pass, the median of difference between daily maximum and daily minimum stage ranged from 2.92 feet for a gage at river mile 3.8 to 3.33 feet for a gage at river mile 1.2. Velocities tended to be unidirectional with some instances of bilateral flow. Reversal in flow direction was common and coincided with rising tides. Monthly mean discharges for the Suwannee River near Wilcox, Florida, during the study period typically were lower than the average for the period of record (1931.97). Discharge near Wilcox averaged 4,000 cubic feet per second (ft3/s) lower than the long-term average from June to September 1996. An El Ni?o event induced precipitation that was responsible for higher than average monthly mean discharge measured near Wilcox during November and December 1997. The maximum observed salinity concentrations for the study period ranged from 28.20 ppt at river mile 3.8 to 31.00 ppt at river mile 1.9. Median daily fluctuations of salinity at river miles 3.8 and 1.2 were 0.12 and 11.31 ppt, respectively. The maximum daily upstream extent of the saltwater/freshwater interface was at or upstream from river mile 4.0 for about 50 percent of the study period. The interface was at or upstream from river mile 3.8 and river mile 2.8 40 and 57 percent of the time. The interface

  1. Modelling of river plume dynamics in Öre estuary (Baltic Sea) with Telemac-3D hydrodynamic model

    Science.gov (United States)

    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.

  2. Sensitivity of Circulation in the Skagit River Estuary to Sea Level Rise and Future Flows

    Energy Technology Data Exchange (ETDEWEB)

    Khangaonkar, Tarang; Long, Wen; Sackmann, Brandon; Mohamedali, Teizeen; Hamlet, Alan F.

    2016-01-01

    Future climate simulations based on the Intergovernmental Panel on Climate Change emissions scenario (A1B) have shown that the Skagit River flow will be affected, which may lead to modification of the estuarine hydrodynamics. There is considerable uncertainty, however, about the extent and magnitude of resulting change, given accompanying sea level rise and site-specific complexities with multiple interconnected basins. To help quantify the future hydrodynamic response, we developed a three dimensional model of the Skagit River estuary using the Finite Volume Coastal Ocean Model (FVCOM). The model was set up with localized high-resolution grids in Skagit and Padilla Bay sub-basins within the intermediate-scale FVCOM based model of the Salish Sea (greater Puget Sound and Georgia Basin). Future changes to salinity and annual transport through the basin were examined. The results confirmed the existence of a residual estuarine flow that enters Skagit Bay from Saratoga Passage to the south and exits through Deception Pass. Freshwater from the Skagit River is transported out in the surface layers primarily through Deception Pass and Saratoga Passage, and only a small fraction (≈4%) is transported to Padilla Bay. The moderate future perturbations of A1B emissions, corresponding river flow, and sea level rise of 0.48 m examined here result only in small incremental changes to salinity structure and inter-basin freshwater distribution and transport. An increase in salinity of ~1 ppt in the near-shore environment and a salinity intrusion of approximately 3 km further upstream is predicted in Skagit River, well downstream of the drinking water intakes.

  3. Bioconcentration of polycyclic aromatic hydrocarbons in roots of three mangrove species in Jiulong River Estuary

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Z.Q.; Zheng, W.J.; Ma, L. [Xiamen University, Xiamen (China). School of Life Science

    2005-07-01

    The polycyclic aromatic hydrocarbons (PAHs) concentrations were determined in the root of three mangrove species (Kandelia candel, Avicennia marina and Bruguiera gymnorrhiza) and their growing environment (sediment) in mangrove wetlands of Jiulong River Estuary, Fujian, China. The total PAHs (16 parent PAHs) in mangrove sediments ranged from 193.44 to 270.53 ng/g dw, with a mean value of 231.76 +/- 31.78 ng/g dw. Compared with other mangrove and coastal marine sediments, the PAHs concentrations of all the sampling areas in this study were at relatively lower level. The total PAHs (13 parent PAHs) values varied from 30.83 to 62.73 ng/g dw in mangrove roots. Benzo(a) pyrene, fluoranthene and pyrene dominated in mangrove sediments. Based on ratios of phenathrene/anthracene, fluoranthene/pyrene and fluoranthene/pyrene + fluoranthene, the main possible sources of surface sediment PAHs were identified as grass, wood or coal combustion for mangrove wetlands of Jiulong River Estuary. Naphthalene and phenathrene were the most abundant compounds in mangrove roots. Sediment-to-vegetation bioconcentration factors (BCF(SV)s) were calculated and their relationships with PAHs' physico-chemical properties were investigated. The average BCF(SV)s of PAHs for three mangrove species roots were almost all under the level of 1 except for naphthalene. Good linear relationship between BCFSV values for mangrove roots and PAHs water solubility, octanol-water partitioning coefficients was derived in present study. The solubility and the octanol-water partition coefficient were proved to be good predictors for the accumulation of PAHs in mangrove roots, respectively.

  4. Continuous river discharge monitoring with bottom-mounted current profilers at narrow tidal estuaries

    Science.gov (United States)

    Garel, E.; D'Alimonte, D.

    2017-02-01

    The objective of this study is to verify whether accurate and continuous estimates of freshwater discharge at the mouth of a narrow estuary with a single channel can be obtained from a bottom-mounted current profiler (ADCP). The focus is on moderate- to high-discharge events that significantly affect the water circulation corresponding to low river flow conditions. Observations at the Guadiana Estuary (southern Iberia) indicate lateral subtidal flow variability, constant cross-channel area, and quasi-steady response of the axial velocity to discharge events. Based on the concept of maximum entropy, the mean and maximum channel velocities were related by a constant ratio, Ω, using data from three cross-channel surveys. This relationship was then used to estimate the freshwater discharge at the mouth based on the maximum velocity obtained from the detided ADCP velocity profiles. This approach was possible because the ADCP was deployed near the position of maximum current velocity, that is, over the deepest part of the channel. The results show good correspondence with observations, indicating that the entropy model can complete or substitute the records from upstream gauged stations that do not include the contribution from downstream tributaries. A Multilayer Perceptron neural net (MLP) based on the entropy approach was then implemented with the purpose of estimating the discharge when Ω is unknown. This latter analysis showsthat the relationship between maximum velocity and discharge is quasi-stationary. Consequently, the MLP can successfully estimate freshwater runoff if the training data represent all statistical properties of the river discharge dynamics. The results also indicate that Ω may vary not only with concomitant hydrographic conditions, but also with the recent (i.e., several days prior) discharge magnitude.

  5. Anaerobic oxidation of methane in coastal sediment from Guishan Island (Pearl River Estuary), South China Sea

    Indian Academy of Sciences (India)

    Zijun Wu; Huaiyang Zhou; Xiaotong Peng; Nan Jia; Yuhong Wang; Linxi Yuan

    2008-12-01

    The concentrations of CH4, SO$^{2−}_{4}$, CO2 and the carbon isotope compositions of CO2 and CH4 in the pore-water of the GS sedimentary core collected from Guishan Island (Pearl River Estuary), South China Sea,were determined. The methane concentration in the pore-water shows dramatic changes and sulfate concentration gradients are linear at the base of the sulfate reduction zone for the station. The carbon isotope of methane becomes heavier at the sulfate-methane transition (SMT)likely because of the Raleigh distillation effect; 12CH4 was oxidized faster than 13CH4 and this caused the enrichment of residual methane 13C and 13C- CO2 minimum. The geochemical profiles of the pore-water support the existence of anaerobic oxidation of methane (AOM), which is mainly controlled by the quality and quantity of the sedimentary organic matter. As inferred from the index of 13C-TOC value and TOC/TN ratio, the organic matter is a mix of mainly refractory terrestrial component plus some labile alga marine-derived in the study area. A large amount of labile organic matter (mainly labile alga marine-derived) is consumed via the process of sedimentary organic matter diagenesis, and this reduces the amount of labile organic matter incorporated into the base of the sulfate reduction zone. Due to the scarcity of labile organic matter, the sulfate will in turn be consumed by its reaction with methane and therefore AOM takes place.Based on a diffussion model, the portion of pore-water sulfate reduction via AOM is 58.6%,and the percentage of CO2 in the pore-water derived from AOM is 41.4%. Thus, AOM plays an important role in the carbon and sulfur cycling in the marine sediments of Pearl River Estuary.

  6. Bioconcentration of polycyclic aromatic hydrocarbons in roots of three mangrove species in Jiulong River Estuary

    Institute of Scientific and Technical Information of China (English)

    LU Zhi-qiang; ZHENG Wen-jiao; MA Li

    2005-01-01

    The polycyclic aromatic hydrocarbons(PAHs) concentrations were determined in the root of three mangrove species( Kandelia candel, Avicennia marina and Bruguiera gymnorrhiza) and their growing environment(sediment) in mangrove wetlands of Jiulong River Estuary, Fujian, China. The total PAHs(16 parent PAHs) in mangrove sediments ranged from 193.44 to 270.53 ng/g dw, with a mean value of 231.76 ± 31.78 ng/g dw. Compared with other mangrove and coastal marine sediments, the PAHs concentrations of all the sampling areas in this study were at relatively lower level. The total PAHs(13 parent PAHs) values varied from 30.83 to 62.73 ng/g dw in mangrove roots. Benzo[a] pyrene(five-ring), fluoranthene(four-ring) and pyrene(four- ring) dominated in mangrove sediments. Based on ratios of phenathrene/anthracene, fluoranthene/pyrene and fluoranthene/pyrene + fluoranthene, the main possible sources of surface sediment PAHs were identified as grass, wood or coal combustion for mangrove wetlands of Jiulong River Estuary. Naphthalene(two-ring)and phenathrene(three-ring) were the most abundant compounds in mangrove roots. Sediment-to-vegetation bioconcentration factors (BCFsvS) were calculated and their relationships with PAHs' physico-chemical properties were investigated. The average BCFsv s of PAHs for three mangrove species roots were almost all under the level of 1 except for naphthalene. Good linear relationship between BCFsv values for mangrove roots and PAHs water solubility, octanol-water partitioning coefficients was derived in present study. The solubility and the octanol-water partition coefficient were proved to be good predictors for the accumulation of PAHs in mangrove roots,respectively.

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

    Institute of Scientific and Technical Information of China (English)

    Xiaojie Mou; Zhigao Sun; Lingling Wang; Chuanyuan Wang

    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.

  8. Contribution of the upper river, the estuarine region, and the adjacent sea to the heavy metal pollution in the Yangtze Estuary.

    Science.gov (United States)

    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.

  9. Raw and Modified Raw Continuous Resistivity Profile Data Collected in the Corsica River Estuary, Maryland on May 15, 2007 on USGS Cruise 07005

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Submarine groundwater discharge (SGD) into Maryland's Corsica River Estuary was investigated as part of a larger study to determine the importance of nutrient...

  10. RES2DINV Format Continuous Resistivity Profile Data Collected in the Corsica River Estuary, Maryland on May 17, 2007 on USGS Cruise 07005

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Submarine groundwater discharge (SGD) into Maryland's Corsica River Estuary was investigated as part of a larger study to determine the importance of nutrient...

  11. RES2DINV Format Continuous Resistivity Profile Data Collected in the Corsica River Estuary, Maryland on May 15, 2007 on USGS Cruise 07005

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Submarine groundwater discharge (SGD) into Maryland's Corsica River Estuary was investigated as part of a larger study to determine the importance of nutrient...

  12. Raw and Modified Raw Continuous Resistivity Profile Data Collected in the Corsica River Estuary, Maryland on May 16, 2007 on USGS Cruise 07005

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Submarine groundwater discharge (SGD) into Maryland's Corsica River Estuary was investigated as part of a larger study to determine the importance of nutrient...

  13. RES2DINV Format Continuous Resistivity Profile Data Collected in the Corsica River Estuary, Maryland on May 16, 2007 on USGS Cruise 07005

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Submarine groundwater discharge (SGD) into Maryland's Corsica River Estuary was investigated as part of a larger study to determine the importance of nutrient...

  14. Raw and Modified Raw Continuous Resistivity Profile Data Collected in the Corsica River Estuary, Maryland on May 17, 2007 on USGS Cruise 07005

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Submarine groundwater discharge (SGD) into Maryland's Corsica River Estuary was investigated as part of a larger study to determine the importance of nutrient...

  15. Modified Processed Continous Resistivity Profile Data Collected in the Corsica River Estuary, Maryland on May 15 and May 16 on USGS Cruise 07005

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Submarine groundwater discharge (SGD) into Maryland's Corsica River Estuary was investigated as part of a larger study to determine the importance of nutrient...

  16. COMBELEV: ESRI Format Binary Grid of the Merged Bathymetry and Elevation Data from the Corsica River Estuary, Maryland For Use with USGS Cruise 07005

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Submarine groundwater discharge (SGD) into Maryland's Corsica River Estuary was investigated as part of a larger study to determine the importance of nutrient...

  17. RES2DINV Format for Modified Continuous Resistivity Profile Data Collected in the Corsica River Estuary, Maryland on May 15 and May 16, 2007 on USGS Cruise 07005

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Submarine groundwater discharge (SGD) into Maryland's Corsica River Estuary was investigated as part of a larger study to determine the importance of nutrient...

  18. Distribution and source identification of trace metals in the sediment of Yellow River Estuary and the adjacent Laizhou Bay

    Science.gov (United States)

    Wang, Yan; Ling, Min; Liu, Ru-hai; Yu, Ping; Tang, Ai-kun; Luo, Xian-xiang; Ma, Qimin

    2017-02-01

    Rapid economic development in the Yellow River basin has inevitably resulted in increase of pollution in the estuary, and concern for both the environment and protection against pollutants is increasing. Contents of trace metals (Cu, Pb Zn, Cr, Cd, As, Hg), Fe, Al, total organic carbon (TOC), and their granulometry were determined in surface sediment samples from the Yellow River estuary and its adjacent areas. Metal contents were significantly correlated each other. Clay, TOC and heavy metal contents showed similar distribution characteristics, with concentrations increased from the land to the sea. The distribution of grain size plays an important role in influencing the distribution of trace metals. Heavy metal concentrations showed a significant relationship with Fe and Al content, while most heavy metals were not enriched. These results were also confirmed by the analysis of enrichment factors and principal component analysis of the metals. The metal content of the Yellow River Estuary sediments was similar to the content observed 20 years ago, but the concentrations of most metals in Laizhou Bay decreased. The decrease in the carrying sediment of the Yellow River might be responsible for this pattern.

  19. Effects of landscape and riparian condition on a fish index of biotic integrity in a large southeastern Brazil river

    Science.gov (United States)

    Environmental conditions of a large river in southeastern Brazil were assessed by evaluating fish assemblage structure (index of biotic integrity, IBI), landscape use (forest, pasture, urban area, and tributary water) and riparian condition. A survey of the 338 km-long middle rea...

  20. Distribution and risk assessment of 82 pesticides in Jiulong River and estuary in South China.

    Science.gov (United States)

    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 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 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.

  1. Sedimentary 4-desmethyl sterols and n-alkanols in an eutrophic urban estuary, Capibaribe River, Brazil.

    Science.gov (United States)

    Fernandes, M B; Sicre, M A; Cardoso, J N; Macêdo, S J

    1999-06-15

    Sterols, n-alkanols, organic carbon (OC), C/N ratios and carbon isotope data (delta 13C) were investigated in sediments of the urban Capibaribe River estuary, NE Brazil, in order to assess allochthonous and autochthonous sources of organic matter (OM). Sedimentary OC values are high, but C/N ratios and delta 13C data generally fall within the range of values reported in other riverine systems, and suggest mixed inputs from aquatic and terrestrial matter. Mean values for total 4-desmethyl sterols and high molecular weight (HMW) n-alkanols are 11.0 micrograms/g and 2.8 micrograms/g, respectively. Sterols are found at highest levels in areas of enhanced urban outfalls. They can be related to major planktonic species growing in riverine waters. Stanol/stenol ratios suggest a high degree of alteration of the autochthonous OM as a result of elevated temperatures and microbiological proliferation. Even though sterols suggest the importance of autochthonous inputs to the river, HMW n-alkanols indicate major terrigenous accumulation at the mouth and 10 km upriver. Coprostanol and epicoprostanol levels are comparable to other sewage contaminated hydrosystems, but not as high as expected given the importance of sewage outfalls and low riverine water discharge. However, high (coprostanol)/(coprostanol + cholestanol) ratio values indicate that fecal contamination is significant.

  2. Sources and preservation of organic matter in recent sediment from the Changjiang (Yangtze River Estuary, China

    Directory of Open Access Journals (Sweden)

    Lü Xiaoxia

    2006-03-01

    Full Text Available The vertical distributions of bulk and molecular biomarker compositions in the samples from four sediment cores of the Changjiang (Yangtze River Estuary were determined. The changes in the bulk and molecular compositions with depth suggest that there have been recent changes in the marine autogenic and terrigenous supply. In the site at the boundary of the turbidity maximum (Site 8 and the most southern site (Site 26, the autogenic and allochthonous inputs make almost the same contribution to sedimentary organic matter. In the site close to the river mouth (Site 11, the organic matter mainly comes from the terrestrial input carried by the Changjiang water, whereas, in the most eastern site (Site 17, the organic matter consists of a mixture of recent and ancient Changjiang delta sedimentary residues. Significant downcore fluctuations were observed in the patterns of the bulk and molecular compositions, as well as in several biomarker ratios, which also indicates the different anoxic conditions at different depths of the core besides the source variation. In addition, the distributions of molecular compounds show that the organic matter is a mixture of immature and mature in the sediments of the four cores, which further indicates that the microbial activity is active in anoxic conditions, especially in the surface sediment. The vertical distributions of molecular compounds also show that the autogenic marine organic matter is more easily degraded, and that the molecular compounds evolve from unstable steric configurations to stable ones in the early diagenetic processes.

  3. Diagenetic alterations of amino acids and organic matter in the upper Pearl River Estuary surface sediments

    Directory of Open Access Journals (Sweden)

    J. Zhang

    2011-03-01

    Full Text Available The objective of this study was to investigate the sources, diagenetic alterations of, and bacterial contributions to sediment organic matter (OM in the upper Pearl River Estuary. Sediment analyses were conducted for three size fractions of OM, including coarse particulate OM (CPOM, fine particulate OM (FPOM, and ultrafiltered dissolved OM (UDOM. Results showed that the highest and lowest carbon (C: nitrogen (N ratios were in CPOM and UDOM, respectively, indicating CPOM was relatively enriched in organic C, whereas FPOM was enriched in N-containing molecules. Distributions of amino acids and their D-isomers among the sediment fractions indicated that the percentage of total N represented by total hydrolysable amino acids, C- and N-normalized yields of total D-amino acids, and C- and N-normalized yields of D-alanine, D-glutamic acid, D-serine could be used as diagenetic indicators of sediment OM. Correlations between the N yields in total D-amino acids and total hydrolysable amino acids, and total N yields suggested that the bacterial N in general reflected the bulk N changes in CPOM, FPOM, and UDOM. Our results demonstrate the crucial role of bacteria as a N source in the terrestrial (soil and vascular plant debris OM transported by the river.

  4. Invasion risks posed by ornamental freshwater fish trade to southeastern Brazilian rivers

    Directory of Open Access Journals (Sweden)

    Andre Lincoln Barroso de Magalhaes

    Full Text Available A model was developed to assess the risk of invasion of ornamental non-native fishes to six rivers in the state of Minas Gerais, southeastern Brazil, with focus on species popularity. Thirty-nine aquarium shops, in six cities, were visited monthly from January to December 2007. In each city, fish species were identified, and their biology and invasion history information was obtained from the literature. We calculated the annual frequency of occurrence and average number of specimens monthly available in stores. Quarterly water temperature and dissolved oxygen data from 1997 to 2007 were obtained for the Velhas, Muriaé, Uberabinha, Sapucaí-Mirim, Doce and Todos os Santos Rivers from public databases. The invasion risk of each species was assessed through a model comprising nine parameters grouped in four variables: (i Invasiveness (thermal and dissolved oxygen ranges, diet, parental care or fecundity, (ii History of invasions (establishment, (iii Propagule pressure (commercial success, comprising annual frequency of occurrence and number of specimens available monthly at stores, and (iv Invasibility (water temperature and dissolved oxygen in the target river compatible with the species ranges. Of the 345 ornamental fish species for sale, 332 are non-native to either Minas Gerais (n = 151 or Brazil (n = 194. Based on the proposed cutting values, in particular the compatibility between species and recipient thermal ranges, five ornamental non-native species (Cyprinus rubrofuscus, Carassius auratus, Xiphophorus hellerii, Poecilia reticulata, and P. latipinna can potentially invade the Velhas and Muriaé Rivers, four species (Cyprinus rubrofuscus, Carassius auratus, X. helleri, and P. reticulata the Uberabinha River, four species (Cyprinus rubrofuscus, Carassius auratus, X. maculatus, and P. reticulata the Sapucaí-Mirim River, three species (Carassius auratus, X. hellerii, and P. reticulata the Doce River, and three species (Cyprinus rubrofuscus

  5. Isotope constraints on seasonal dynamics of dissolved and particulate N in the Pearl River Estuary, south China

    Science.gov (United States)

    Ye, Feng; Jia, Guodong; Xie, Luhua; Wei, Gangjian; Xu, Jie

    2016-12-01

    Isotope measurements were performed on dissolved NO3-, NH4+, and suspended particulate total N along a salinity gradient in the Pearl River Estuary (PRE) to investigate seasonal changes in main N sources and its biogeochemical processing under the influence of monsoon climate. Our data revealed that municipal sewage and remineralized soil organic N were the major sources of DIN (NO3- and/or NH4+) in freshwater during winter and summer, respectively, whereas phytoplankton biomass was a major component of PN in both seasons. In low-salinity waters (responsible for the decoupling. At high salinities, the greater enrichment in δ18ONO3 than in δ15NNO3 (up to 15.6‰) in winter suggests that atmospheric deposition may contribute to NO3- delivery during the dry season. Overall, these results show the importance of seasonal variability in physical forcing on biological N sources and its turnover processes in the highly dynamic river-dominated estuary.

  6. Sedimentation and lithological structure of the surface sedimentary strata in the shallow estuary of the River Grendalen (Gren-fjord

    Directory of Open Access Journals (Sweden)

    Meshcheryakov N. I.

    2016-03-01

    Full Text Available This paper presents the results of studies of the River Grendalen estuary shallow (Gren-fjord. It is based on materials of the field work carried out in 2014. The waters sonar research, sampling in the intertidal zone, selection of ground shock tube samples, sensing by thermohaline component, determining the amount of particulate matter in the surface water have been produced. The granulometric analysis of samples of loose deposits has been made. According to the sonar data the bathymetric model of the study area has been built. The scheme of distribution of suspended matter in the estuarial area of the River Grendalen and adjacent waters has been made. The factors influenced the movement of sediment and the formation of the modern subaqueous landscape in the region have been analyzed

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

    Science.gov (United States)

    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.

  8. Multi-Scale Action Effectiveness Research in the Lower Columbia River and Estuary, 2011 - FINAL ANNUAL REPORT

    Energy Technology Data Exchange (ETDEWEB)

    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.

  9. Migratory Behavior and Survival of Juvenile Salmonids in the Lower Columbia River, Estuary, and Plume in 2010

    Energy Technology Data Exchange (ETDEWEB)

    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

  10. Methylmercury and sulfate-reducing bacteria in mangrove sediments from Jiulong River Estuary, China

    Institute of Scientific and Technical Information of China (English)

    Hao Wu; Haoliang Lu; Zhenhua Ding; Yang Liu; Jinling Liu; Haiyu Yan; Jiayong Pan; Liuqiang Li; Huina Lin; Guanghui Lin

    2011-01-01

    Estuaries are important sites for mercury (Hg) methylation, with sulfate-reducing bacteria (SRB) thought to be the main Hg methylators. Distributions of total mercury (THg) and methylmercury (MeHg) in mangrove sediment and sediment core from Jiulong River Estuary Provincial Mangrove Reserve, China were determined and the possible mechanisms of Hg methylation and their controlling factors in mangrove sediments were investigated. Microbiological and geochemical parameters were also determined.Results showed that SRB constitute a small fraction of total bacteria (TB) in both surface sediments and the profile of sediments. The content ofTHg, MeHg, TB, and SRB were (350± 150) rig/g, (0.47 ± 0.11) ng/g, (1.4 ×1011 ± 4.1 × 109) cfu/g dry weight (dw), and (5.0 × 106 ± 2.7 × 106) cfu/g dw in surficial sediments, respectively, and (240 ± 24) ng/g, (0.30 ± 0.15) ng/g, (1.9 × 1011± 4.2 × 1010) cfu/g dw, and (1.3× 106 ± 2.0 × 106) cfu/g dw in sediment core, respectively. Results showed that THg, MeHg, TB, MeHg/THg, salinity and total sulfur (TS) increased with depth, but total organic matter (TOM), SRB, and pH decreased with depth. Concentrations of MeHg in sediments showed significant positive correlation with THg, salinity, TS, and MeHg/THg, and significant negative correlation with SRB, TOM, and pH. It was concluded that other microbes, rather than SRB, may also act as main Hg methylators in mangrove sediments.

  11. Distribution patterns of phytoplankton in the Changjiang River estuary and adjacent waters in spring 2009

    Science.gov (United States)

    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.

  12. Gametogenic development and spawning of the freshwater clam, Galatea paradoxa (Born 1778) from the Volta River Estuary, Ghana.

    Science.gov (United States)

    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.

  13. A new record of Cleantioides emarginata Kwon & Kim,1992 (Crustacea, Isopoda, Valvifera) from Changjiang River estuary, China

    Institute of Scientific and Technical Information of China (English)

    LIU Wenliang; Gary C.B.POORE

    2013-01-01

    At present,descriptions of Cleantioides emarginata Kwon & Kim,1992 have been limited to the type locality of Pusan,Korea.In this study,we discovered this species in the Changjiang (Yangtze) River estuary,China.This represents an extension of the known geographical range of C.emarginata.In addition,we present information of a colour pattern not previously described,along with details on the estuarine habitat of the species.

  14. Natural diet and feeding habits of a freshwater prawn (Macrobrachium carcinus: Crustacea, Decapoda) in the estuary of the Amazon River.

    OpenAIRE

    LIMA, J.F.; GARCIA, J. da S.; SILVA, T. C. da

    2014-01-01

    Macrobrachium carcinus is a Brazilian native prawn with recognized potential for use in aquaculture activities. However, there is little information about the natural diet and feeding habits of this species. The aim of this study was the identification of the diet items of M. carcinus based on the analysis of the stomach contents. Specimens were collected in the Amazon River estuary between January 2009 and January 2010. The stomach analysis was carried out by using the frequency of occurrenc...

  15. Salmon Life Histories, Habitat, and Food Webs in the Columbia River Estuary: An Overview of Research Results, 2002-2006.

    Energy Technology Data Exchange (ETDEWEB)

    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

  16. Weight-of-evidence approach in assessment of ecotoxicological risks of acid sulphate soils in the Baltic Sea river estuaries

    Energy Technology Data Exchange (ETDEWEB)

    Wallin, Jaana, E-mail: jaana.wallin@jyu.fi [Finnish Environment Institute SYKE, Survontie 9 A, FI-40500 Jyväskylä (Finland); Karjalainen, Anna K. [Finnish Environment Institute SYKE, Survontie 9 A, FI-40500 Jyväskylä (Finland); Schultz, Eija [Finnish Environment Institute SYKE, Hakuninmaantie 6, FI-00430 Helsinki (Finland); Järvistö, Johanna; Leppänen, Matti; Vuori, Kari-Matti [Finnish Environment Institute SYKE, Survontie 9 A, FI-40500 Jyväskylä (Finland)

    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. - Highlights: • Acid sulphate soils release high amounts of metals and acidity. • Metals and acidity are transported to estuary sites. • Acid sulphate soils impair the ecological status

  17. Diatoms as Proxies for Abrupt Events in the Hudson River Estuary

    Science.gov (United States)

    Skorski, W.; Abbott, D. H.; Recasens, C.; Breger, D. L.

    2014-12-01

    The Hudson River estuary has been subject to many abrupt events throughout its history including hurricanes, droughts and pluvials. Hurricanes in particular are rare, discrete events that if fingerprinted can be used to develop better age models for Hudson River sediments. Proxies use observed physical characteristics or biological assemblages (e.g. diatom and foraminiferal assemblages) as tools to reconstruct past conditions prior to the modern instrumental record. Using a sediment core taken from the Hudson River (CDO2-29A), in New York City, drought and pluvial layers were selected based on Cs-137 dating while hurricane layers were determined from occurrences of tropical to subtropical foraminifera. Contrary to previous studies (Weaver, 1970, Weiss et al, 1978), more than sixty different diatom species have been identified using a scanning electron microscope (SEM). Cosmopolitan, hurricane and drought assemblages have begun to be identified after observing multiple layers (Table 1). Tropical foraminifera dominated by Globigerinoides ruber pink were also found in a hurricane layer that we infer was deposited during Hurricane Belle in 1976. More diatom abundance analyses and cataloged SEM pictures will provide further insight into these proxies. Table 1 Diatom Genera and Species Environment Clarification Cyclotella caspia Planktonic, marine-brackish Cosmopolitan Karayevia clevei Freshwater Cosmopolitan Melosira sp Planktonic, marine Cosmopolitan Thalassiosira sp Marine, brackish Cosmopolitan Staurosirella leptostauron Benthic, freshwater Cosmopolitan Actinoptychus senarius Planktonic or benthic, freshwater to brackish Hurricane and pluvial layers Amphora aff. sp Benthic, marine or freshwater Hurricane layers only Nitzschia sp Benthic, marine or freshwater Hurricane layers only Gomphonema sp Freshwater Hurricane layers only Surirella sp Marine-brackish Drought layer only Triceratium sp Marine Drought layer only Other Genera and species Environment Clarification

  18. Suspended sediment transport in the Deepwater Navigation Channel, Yangtze River Estuary, China, in the dry season 2009: 2. Numerical simulations

    Science.gov (United States)

    Song, Dehai; Wang, Xiao Hua

    2013-10-01

    A three-dimensional wave-current-sediment coupled numerical model with wetting and drying process is developed to understand hydrodynamics and sediment transport dynamics in the Deepwater Navigation Channel (DNC), the North Passage of the Yangtze River Estuary (YRE), China. The model results are in good agreement with observed data, and statistics show good model skill scores and correlation coefficients. The model well reproduces the spring-neap variation between a well-mixed estuary and a highly stratified estuary. Model results indicate that the estuarine gravitational circulation plays the most important role in the estuarine turbidity maximum (ETM) formation in the DNC. The upstream nonlocal sediment intrusion through the spillover mechanism is a major source of sediment trapping in the North Passage after the morphological changes. Numerical studies are conducted to show scenarios in the YRE under the effects of different forcings (river discharges, waves, and winds). Between these study cases, surface-wave-breaking relieves the sediment trapping and bottom-wave-current-interaction aggravates the bed erosion and elevates the SSC in the ETM; the former and the latter have the least and largest influence on the suspended sediment transport in the DNC. The wind effects have a greater influence on sediment trapping than the river discharges, and the steady northwesterly wind condition favors the siltation in the DNC most. The significance of density-driven turbidity current is also assessed, which can enhance the saline-water intrusion and suppress the turbulent mixing in the bottom boundary layer.

  19. THREE-DIMENSIONAL NONLINEAR NUMERICAL MODEL WITH INCLINED PRESSURE FOR SALTWATER INTRUSION AT THE YANGTZE RIVER ESTUARY

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A three-dimensional nonlinear numerical model with inclined pressure was developed to compute the saltwater intrusion at the Yangtze River Estuary. The σ-transformation was introduced in the vertical plane to achieve the same lattices in the whole domain of interest. The mode-splitting technique splits the three-dimensional governing equations into the surface gravity waves (external mode) and the internal gravity waves (internal mode). And the external mode was solved by the improved double-sweep-implicit (DSI) finite difference method and the internal mode was solved by the Eulerian-Lagrangian method. The Eulerian-Lagrangian method could not only reduce the numerical diffusion but also increase the computational accuracy by the improvement of the finite difference scheme in the vertical direction. Application of the model to the Yangtze River Estuary was carried out for the calculation of the saltwater intrusion and the null point. Results of the temporal and spatial distribution of the flow velocity and the salinity coincide with the measured data quite well. The formation and location of the underwater sandbars in the North Channel of the Yangtze River Estuary are closely related to the local salinity, the null point, the predominant current and the residual flow.

  20. A model study of influence of circulation on the pollutant transport in the Zhujiang River Estuary and adjacent coastal waters

    Institute of Scientific and Technical Information of China (English)

    WONG Lai Ah; GUAN Weibing; CHEN Jay-Chung; SU Jilan

    2004-01-01

    A tracer model with random diffusion coupled to the hydrodynamic model for the Zhujiang River Estuary (Pearl River Estuary, PRE) is to examine the effect of circulations on the transport of completely conservative pollutants. It is focused on answering the following questions: (1) What role does the estuarine plume front in the winter play in affecting the pollutants transport and its distribution in the PRE ? (2) What effect do the coastal currents driven by the monsoon have on the pollutants transport? The tracer experiment results show that: (1) the pollutant transport paths strongly depend on the circulation structures and plume frontal dynamics of the PRE and coastal waters; (2) during the summer when a southwesterly monsoon prevails, the pollutants from the four easterly river inlets and those from the bottom layer of offshore stations will greatly influence the water quality in Hong Kong waters, however, the pollutants released from the four westerly river-inlets will seldom affect the water quality of Hong Kong waters due to their transport away from Hong Kong; (3) during the winter when a northeasterly monsoon prevails, all pollutants released from the eight river gates will be laterally transported seaward inside the estuary and transport westward in the coastal waters along the river plume frontal zone. However, pollutants released from the surface layer of offshore stations near or east of the Dangan Channel will be carried into the coastal waters of Hong Kong by the landward component of the westward coastal current driven by the winter northeasterly monsoon. But the pollutants from the bottom layer of the offshore stations will be carried away from the offshore by the bottom flow driven by the northeasterly monsoon. This implies that only surface-released matter from offshore stations will affect the water quality of the coastal waters around Hong Kong during the winter when a northeasterly monsoon prevails.

  1. Environmental drivers of Ross River virus in southeastern Tasmania, Australia: towards strengthening public health interventions.

    Science.gov (United States)

    Werner, A K; Goater, S; Carver, S; Robertson, G; Allen, G R; Weinstein, P

    2012-02-01

    In Australia, Ross River virus (RRV) is predominantly identified and managed through passive health surveillance. Here, the proactive use of environmental datasets to improve community-scale public health interventions in southeastern Tasmania is explored. Known environmental drivers (temperature, rainfall, tide) of the RRV vector Aedes camptorhynchus are analysed against cumulative case records for five adjacent local government areas (LGAs) from 1993 to 2009. Allowing for a 0- to 3-month lag period, temperature was the most significant driver of RRV cases at 1-month lag, contributing to a 23·2% increase in cases above the long-term case average. The potential for RRV to become an emerging public health issue in Tasmania due to projected climate changes is discussed. Moreover, practical outputs from this research are proposed including the development of an early warning system for local councils to implement preventative measures, such as public outreach and mosquito spray programmes.

  2. A network model shows the importance of coupled processes in the microbial N cycle in the Cape Fear River Estuary

    Science.gov (United States)

    Hines, David E.; Lisa, Jessica A.; Song, Bongkeun; Tobias, Craig R.; Borrett, Stuart R.

    2012-06-01

    Estuaries serve important ecological and economic functions including habitat provision and the removal of nutrients. Eutrophication can overwhelm the nutrient removal capacity of estuaries and poses a widely recognized threat to the health and function of these ecosystems. Denitrification and anaerobic ammonium oxidation (anammox) are microbial processes responsible for the removal of fixed nitrogen and diminish the effects of eutrophication. Both of these microbial removal processes can be influenced by direct inputs of dissolved inorganic nitrogen substrates or supported by microbial interactions with other nitrogen transforming pathways such as nitrification and dissimilatory nitrate reduction to ammonium (DNRA). The coupling of nitrogen removal pathways to other transformation pathways facilitates the removal of some forms of inorganic nitrogen; however, differentiating between direct and coupled nitrogen removal is difficult. Network modeling provides a tool to examine interactions among microbial nitrogen cycling processes and to determine the within-system history of nitrogen involved in denitrification and anammox. To examine the coupling of nitrogen cycling processes, we built a nitrogen budget mass balance network model in two adjacent 1 cm3 sections of bottom water and sediment in the oligohaline portion of the Cape Fear River Estuary, NC, USA. Pathway, flow, and environ ecological network analyses were conducted to characterize the organization of nitrogen flow in the estuary and to estimate the coupling of nitrification to denitrification and of nitrification and DNRA to anammox. Centrality analysis indicated NH4+ is the most important form of nitrogen involved in removal processes. The model analysis further suggested that direct denitrification and coupled nitrification-denitrification had similar contributions to nitrogen removal while direct anammox was dominant to coupled forms of anammox. Finally, results also indicated that partial

  3. Remotely sensed variability of the suspended sediment concentration and its response to decreased river discharge in the Yangtze estuary and adjacent coast

    Science.gov (United States)

    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.

  4. 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

    Science.gov (United States)

    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.

  5. Tracing the origin of the oxygen-consuming organic matter in the hypoxic zone in a large eutrophic estuary: the lower reach of the Pearl River Estuary, China

    Directory of Open Access Journals (Sweden)

    J. Su

    2017-09-01

    Full Text Available We assess the relative contributions of different sources of organic matter, marine vs. terrestrial, to oxygen consumption in an emerging hypoxic zone in the lower Pearl River Estuary (PRE, a large eutrophic estuary located in Southern China. Our cruise, conducted in July 2014, consisted of two legs before and after the passing of Typhoon Rammasun, which completely de-stratified the water column. The stratification recovered rapidly, within 1 day after the typhoon. We observed algal blooms in the upper layer of the water column and hypoxia underneath in bottom water during both legs. Repeat sampling at the initial hypoxic station showed severe oxygen depletion down to 30 µmol kg−1 before the typhoon and a clear drawdown of dissolved oxygen after the typhoon. Based on a three endmember mixing model and the mass balance of dissolved inorganic carbon and its isotopic composition, the δ13C of organic carbon remineralized in the hypoxic zone was −23.2 ± 1.1 ‰. We estimated that 65 ± 16 % of the oxygen-consuming organic matter was derived from marine sources, and the rest (35 ± 16 % was derived from the continent. In contrast to a recently studied hypoxic zone in the East China Sea off the Changjiang Estuary where marine organic matter dominated oxygen consumption, here terrestrial organic matter significantly contributed to the formation and maintenance of hypoxia. How varying amounts of these organic matter sources drive oxygen consumption has important implications for better understanding hypoxia and its mitigation in bottom waters.

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

    Science.gov (United States)

    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

  7. The exploited population of the brackish river prawn (Macrobrachium macrobrachion Herklots 1851 in the Cross River estuary, Nigeria

    Directory of Open Access Journals (Sweden)

    Francis M. Nwosu

    2007-03-01

    Full Text Available The dynamics of the exploited population of Macrobrachium macrobrachion in the Cross River estuary, Nigeria, were studied based on monthly length-frequency data collected from January 1997 to June 1998 (18 months, from the landings of the artisanal Macrobrachium fishery. Sexual dimorphism was indicated in the growth and mortality parameters. For the males, the von Bertalanffy growth parameters were estimated as L∞ = 141.35 mm, K = 1.21 year-1, C = 1.0 and WP = 0.15. For the females, they were L∞ = 117.55 mm, K = 1.60 year-1, C = 0.81 and WP = 0.51. The instantaneous rate of total mortality (Z was estimated as 9.53 year-1 (males and 9.14 year-1 (females. The instantaneous rate of natural mortality (M was estimated as 2.44 year-1 (males and 3.09 year-1 (females, while the instantaneous rate of fishing mortality (F was estimated as 7.09 year-1 (males and 6.05 year-1 (females. The exploitation rate (E obtained was 0.74 for the males and 0.66 for the females, suggesting that the prawn population was over-fished for both sexes. It is necessary to analyse the catch and effort data for the last 10 years and to apply other methods of stock assessment in order to estimate the long term trends in the fishery.

  8. Myrionecta Rubra Population Genetic Diversity and Its Cryptophyte Chloroplast Specificity in Recurrent Red Tides in the Columbia River Estuary

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Science.gov (United States)

    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.

  10. Investigating the Impacts of Landuse-landcover (LULC) Change in the Pearl River Delta Region on Water Quality in the Pearl River Estuary and Hong Kong’s Coast

    OpenAIRE

    Hongyan Xi; Yuanzhi Zhang; Yunpeng Wang; Yufei Wang

    2009-01-01

    Water quality information in the coastal region of Hong Kong and the Pearl River Estuary (PRE) is of great concern to the local community. Due to great landuse-landcover (LULC) changes with rapid industrialization and urbanization in the Pearl River Delta (PRD) region, water quality in the PRE has worsened during the last 20 years. Frequent red tide and harmful algal blooms have occurred in the estuary and its adjacent coastal waters since the 1980s and have caused important economic losses, ...

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

    Science.gov (United States)

    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.

  12. Estuarine Habitats for Juvenile Salmon in the Tidally-Influenced Lower Columbia River and Estuary : Reporting Period September 15, 2008 through May 31, 2009.

    Energy Technology Data Exchange (ETDEWEB)

    Baptista, António M. [Oregon Health & Science University, Science and Technology Center for Coastal Margin Observation and Prediction

    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

  13. [Distribution of polybrominated diphenyl ethers in aquatic species from the Pearl River Estuary].

    Science.gov (United States)

    Xiang, Cai-hong; Luo, Xiao-jun; Yu, Mei; Meng, Xiang-zhou; Mai, Bi-xian; Zeng, Eddy

    2006-09-01

    Polybrominated diphenyl ethers (PBDEs) were detected in biota samples collected from the Pearl River Estuary. The concentrations of sigma10 PBDEs (BDE28, 47, 66, 100, 99, 85, 154, 153, 138, 183) in fish species (including Platycephalus indicus, Pseudosiaena crocea , Pampus argenteus, Cynoglossus robustus, and Harpodon nehereus), shrimps (including Metapenaeus ensis and Metapenaeus affinis) and Squilla oratoria were from 37.8 ng x g(-1) to 407.1 ng x g(-1) (normalized to lipid), from 49.0 ng x g(-1) to 239.1 ng x g(-1) and from 142 ng x g(-1) to 444.5 ng x g(-1), respectively. BDE47 was the dominant congener in all biota samples, with a contribution to sigma10 PBDEs ranging from 53.7% to 66.9%. Differences in concentrations of PBDEs and PBDE patterns in different species may be related to the different feeding habit, living environment and uptaking or elimination rate. High ratios of concentrations of PBDEs in liver /muscle in fish species indicated that PBDEs tended to accumulate more in liver than in muscle.

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

    Science.gov (United States)

    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. Zooplankton community analysis in the Changjiang River estuary by single-gene-targeted metagenomics

    Science.gov (United States)

    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 (similaritymorphological methods were identified by molecular methods, especially gelatinous zooplankton and merozooplankton that were likely sampled at different life history phases. Zooplankton community structures differed significantly among all of the samples. The MOTU spatial distributions were influenced by the ecological habits of the corresponding species. In conclusion, single-gene-targeted metagenomic analysis is a useful tool for zooplankton studies, with which specimens from all life history stages can be identified quickly and effectively with a comprehensive database.

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

    Science.gov (United States)

    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.

  17. Lower Columbia River and Estuary Ecosystem Restoration Program Reference Site Study: 2011 Restoration Analysis - FINAL REPORT

    Energy Technology Data Exchange (ETDEWEB)

    Borde, Amy B.; Cullinan, Valerie I.; Diefenderfer, Heida L.; Thom, Ronald M.; Kaufmann, Ronald M.; Zimmerman, Shon A.; Sagar, Jina; Buenau, Kate E.; Corbett, C.

    2012-05-31

    The Reference Site (RS) study is part of the research, monitoring, and evaluation (RME) effort developed by the Action Agencies (Bonneville Power Administration [BPA], U.S. Army Corps of Engineers, Portland District [USACE], and U.S. Bureau of Reclamation) in response to Federal Columbia River Power System (FCRPS) Biological Opinions (BiOp). While the RS study was initiated in 2007, data have been collected at relatively undisturbed reference wetland sites in the LCRE by PNNL and collaborators since 2005. These data on habitat structural metrics were previously summarized to provide baseline characterization of 51 wetlands throughout the estuarine and tidal freshwater portions of the 235-km LCRE; however, further analysis of these data has been limited. Therefore, in 2011, we conducted additional analyses of existing field data previously collected for the Columbia Estuary Ecosystem Restoration Program (CEERP) - including data collected by PNNL and others - to help inform the multi-agency restoration planning and ecosystem management work underway in the LCRE.

  18. Benthic nutrient fluxes in the intertidal flat within the Changjiang (Yangtze River) Estuary

    Institute of Scientific and Technical Information of China (English)

    GAO Lei; LI Daoji; WANG Yanming; YU Lihua; KONG Dingjiang; LI Mei; LI Yun; FANG Tao

    2008-01-01

    In an annual cycle from March 2005 to February 2006, benthic nutrient fluxes were measured monthly in the Dongtan intertidal flat within the Changjiang (Yangtze River) Estuary. Except for NH4+, there always showed high fluxes from overlying water into sediment for other four nutrients. Sediments in the high and middle marshes, covered with halophyte and consisting of macrofauna, demonstrated more capabilities of assimilating nutrients from overlying water than the low marsh. Sampling seasons and nutrient concentrations in the overlying water could both exert significant effects on these fluxes. Additionally, according to the model provided by previous study, denitrification rates, that utilizing NO3- transported from overlying water (DW) in Dongtan sediments, were estimated to be from -16 to 193 μmol·h-1·m-2 with an average value of 63 μmol·h-1·m-2 (n=18). These estimated values are still underestimates of the in-situ rates owing to the lack of consideration of DN, I.e., denitrification supported by the local NO3- production via nitrification.

  19. Statistical modeling and trend detection of extreme sea level records in the Pearl River Estuary

    Science.gov (United States)

    Wang, Weiwen; Zhou, Wen

    2017-03-01

    Sea level rise has become an important issue in global climate change studies. This study investigates trends in sea level records, particularly extreme records, in the Pearl River Estuary, using measurements from two tide gauge stations in Macau and Hong Kong. Extremes in the original sea level records (daily higher high water heights) and in tidal residuals with and without the 18.6-year nodal modulation are investigated separately. Thresholds for defining extreme sea levels are calibrated based on extreme value theory. Extreme events are then modeled by peaks-over-threshold models. The model applied to extremes in original sea level records does not include modeling of their durations, while a geometric distribution is added to model the duration of extremes in tidal residuals. Realistic modeling results are recommended in all stationary models. Parametric trends of extreme sea level records are then introduced to nonstationary models through a generalized linear model framework. The result shows that, in recent decades, since the 1960s, no significant trends can be found in any type of extreme at any station, which may be related to a reduction in the influence of tropical cyclones in the region. For the longer-term record since the 1920s at Macau, a regime shift of tidal amplitudes around the 1970s may partially explain the diverse trend of extremes in original sea level records and tidal residuals.

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

    Science.gov (United States)

    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 absorption efficiency of TN and TP than P. australis (P nitrogen- and phosphorus absorption efficiency of the plants.

  1. Cyst Formation, Development of Alexandrium tamarense from Yangtse River Estuary and Its Relation to Bloom Dynamics

    Institute of Scientific and Technical Information of China (English)

    GUHai-Feng; LANDong-Zhao; FANGQi; WANGZong-Ling

    2004-01-01

    The toxic dinoflagellate—Alexandrium tamarense (Lebour) Balech, formed resting cysts in f/2 media with low nitrate concentrations. Among the concentrations tested, f/20 NO3- was the most effective to induction with an encystment percentage of 2.0 in batch culture. About 73.2% and 17.6% of cysts were produced on 8 and 9 d after transferring. Newly formed cysts developed accumulation body 3d later and kept forming mucilaginous substance, which might help their dispersal and survival. The mandatory dormancy period of resting cysts was 15 and 10d when stored at 15 and 20℃ respectively. The cysts could germinate without temperature change, with germination of 75.6% 20d after formation at 20℃. The Alexandrium cyst density in the surface sediment of DG-26 station reached above 25 cysts/g in May and November of 2002, and dropped to 4.5 and 0.9 cysts/g in August of 2002 and February of 2003, suggesting that Alexandrium cysts might have germinated in spring and autumn 2002. Cysts produced during the bloom returned to water column soon, whatever the season and water temperature were. The cyst density in the surface sediment at DG-26 station in May, 2003 was only 3.3 cysts/g and the cysts were newly formed. In the Yangtse River estuary, the inoculum size was not a major factor to determine the outbreak of A.tamarense bloom.

  2. TRANSFERABLE PHOSPHORUS IN SEDIMENTS OF THE HUANGHE RIVER ESTUARY'S ADJACENT WATERS

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Based on a new idea for research on cycling of marine biogenic elements, this study showed that only the leachable form phosphorus in natural grain sizes marine sediments constitutes the transferable phosphorous in the sediments. The transferable phosphorus content in the natural grain sizes surface sediments in the Huanghe River estuary adjacent waters ranges from 58.5-69.8 μg/g, accounting for only 9.1%-11.0% of the total phosphorus content, whereas the leachable form (“transferable") phosphorus content in the sediment after it was totally ground into powder was found to be 454.8-529.2 μg/g, accounting for 73.4%-89.1% of the total phosphorus. Analysis of the correlation between the biomass of benthos and the leachable form (“transferable") phosphorus showed that most of the leachable form (“transferable") phosphorus in the totally ground sediment did not participate in the marine biogeochemical cycling. Furthermore, a synchronous survey on benthos showed that the biomass of meio-and macro-benthos exhibited good positive correlation with the leachable form of phosphorus in the natural grain sizes sediment, but poorer correlation with the leachable form (“transferable") phosphorus in the totally ground sediment, indicating that transferable phosphorus in marine sediment is the leachable form of phosphorus in the natural grain sizes sediments, and is not the previously known leachable form (“transferable") phosphorus obtained from the totally ground sediment.

  3. Dynamics of Coastal Land Use Patterns of Inner Lingdingyang Bay in the Zhujiang River Estuary

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    To satisfy the growing of land demand from economic development, a large scale of land reclamation from sea has been carried out in Inner Lingdingyang Bay in the Zhujiang (Pearl) River estuary in recent years. As a result,the tidal flat and the water channels became narrow, the frequency of floods increased, and the environment was undermined. Guangzhou Marine Geological Survey (GMGS) conducted an integrated project for marine geo-environment and geo-hazards survey in 2003. With the integration of multi-temporal remote sensing images of 1977, 1978,1988, 1996, and 2003, GIS spatial analyzing approach and GPS technique, as well as field data and other background data of the region, this research investigated the comprehensive characteristics and the drivers of coastal land use dynamics and shoreline changes in Inner Lingdingyang Bay. The results reveal that the reclaimed coastal land was mainly for agriculture and aquaculture in early years, but now they are used for construction sites of harbors and industries, especially high-tech industry.

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

    Institute of Scientific and Technical Information of China (English)

    KE Zhixin; HUANG Liangmin; TAN Yehui; SONG xingyu

    2012-01-01

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

  5. Body condition and gametogenic cycle of Galatea paradoxa (Mollusca: Bivalvia) in the Volta River estuary, Ghana

    Science.gov (United States)

    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.

  6. Bioavailability and risk assessment of arsenic in surface sediments of the Yangtze River estuary.

    Science.gov (United States)

    Wang, Haotian; Liu, Ruimin; Wang, Qingrui; Xu, Fei; Men, Cong; Shen, Zhenyao

    2016-12-15

    The bioavailability and risk assessment of As were studied in sediments of the Yangtze River estuary (YRE). Results showed that residual fractions dominated the As partition (>85%), which attenuated overall bioavailability. After the residual fraction, As mainly partitioned into the Fe-Mn oxides fraction (3.16-4.22%). Arsenic bound to Fe-Mn oxides was higher in wet seasons. The carbonate fraction was minimal, which may result from the negative state presence of As in sediments. According to the risk assessment code, the YRE was classified as low risk. Additionally, the reduction of As(V) to As(III) may occur due to the reducing condition in wet seasons. Considering As(III) is more toxic and mobile, As bound to the exchangeable and Fe-Mn oxides fractions may have more potential ecological risk. Thus, the speciation and fraction should be both considered on the ecological risk of As in sediments of the YRE. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

    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.

  8. Modeling River Hydrologic Regime and Spawning of Migratory Catfishes in Southeastern Peruvian Amazon

    Science.gov (United States)

    Canas, C. M.; Waylen, P. R.

    2008-05-01

    Seasonal hydrologic conditions and catfish larvae production were evaluated in the Madre de Dios River in order to determine whether environmental conditions influence the reproductive activity of a group of large, commercially important catfishes, in the Southeastern Peruvian Amazon. A simple stochastic model of floods is presented to describe the influence of the natural high flow regime on observed patterns of catfish larvae release and drifting. Daily river stage records at Puerto Maldonado are related to weekly larval catches to determine the association between flood and spawning events. On the basis of hydroclimatologic characteristics of Andean- Amazon regions, available long-term historical rainfall records are employed to approximate the likely inter- annual variability of floods within this Amazon headwater basin. Major larval drift appeared associated with stages of over the 5 m, or "Biologic Hydrologic Significant Events" (BSE), which act as triggers, or a reasonable surrogates, for spawning responses of these species. The timing of BSEs, estimated from the historical rainfall records, appear to be uniformly distributed during the rain season and their inter-arrival times exponential. These observations provided the basis of the stochastic model describing the likelihood of volumes of larvae releases from the headwater region to lowland Amazon. The ecologically significant role of the hydroclimatology of this region in the complete life cycle of this important Amazon fish resource is illustrated.

  9. Controls on oxygen dynamics in a riverine salt-wedge estuary - a three-dimensional model of the Yarra River estuary, Australia

    Science.gov (United States)

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

    2013-07-01

    Oxygen depletion in estuarine waters is an important factor governing water quality and ecological health. A complex and dynamic balance of physical and biogeochemical factors drive the extent and persistence of hypoxia and anoxia making it difficult to predict. An increased understanding of the effect of changing flow regimes and temperature on patterns of estuarine oxygen depletion is required to support ongoing management. Coupled physical and biogeochemical models have been applied to study the interaction of physical processes and seasonal hypoxia, however, application to riverine estuaries with tight curvature and more sporadic periods of oxygen depletion is rare. In this study we apply a finite volume 3-D hydrodynamic-biogeochemical model (TUFLOW-FV-FABM) to the Yarra River estuary, Australia, in order to predict the extent of salt-wedge intrusion and consequent patterns of oxygen depletion. The predictive capacity of the model was evaluated using a series of model verification metrics and the results evaluated to determine the dominant mechanisms affecting salt-wedge position and the extent and persistence of anoxia and hypoxia. Measures of model fit indicated that the model reasonably captured the strength of stratification and the position and extent of the salt wedge (r2 ~ 0.74). The extent of the salt wedge intrusion was controlled by riverine flow and the strength of stratification or mixing dominated by topographical features corresponding to areas of tight curvature ("horseshoe" bends). The model predicted that the extent of anoxic waters generally mimicked the extent of the salt wedge (r2 ~ 0.65) increasing during periods of low flow and reduced following episodic high flow events. The results showed two sporadically isolated "hot spots" of anoxia, the first downstream of the horseshoe bend and the second downstream of a sill. Simulated oxygen concentrations indicated that whilst a threshold salt wedge intrusion was a requirement of oxygen depletion

  10. Controls on oxygen dynamics in a riverine salt-wedge estuary – a three-dimensional model of the Yarra River estuary, Australia

    Directory of Open Access Journals (Sweden)

    L. C. Bruce

    2013-07-01

    Full Text Available Oxygen depletion in estuarine waters is an important factor governing water quality and ecological health. A complex and dynamic balance of physical and biogeochemical factors drive the extent and persistence of hypoxia and anoxia making it difficult to predict. An increased understanding of the effect of changing flow regimes and temperature on patterns of estuarine oxygen depletion is required to support ongoing management. Coupled physical and biogeochemical models have been applied to study the interaction of physical processes and seasonal hypoxia, however, application to riverine estuaries with tight curvature and more sporadic periods of oxygen depletion is rare. In this study we apply a finite volume 3-D hydrodynamic-biogeochemical model (TUFLOW-FV–FABM to the Yarra River estuary, Australia, in order to predict the extent of salt-wedge intrusion and consequent patterns of oxygen depletion. The predictive capacity of the model was evaluated using a series of model verification metrics and the results evaluated to determine the dominant mechanisms affecting salt-wedge position and the extent and persistence of anoxia and hypoxia. Measures of model fit indicated that the model reasonably captured the strength of stratification and the position and extent of the salt wedge (r2 ~ 0.74. The extent of the salt wedge intrusion was controlled by riverine flow and the strength of stratification or mixing dominated by topographical features corresponding to areas of tight curvature ("horseshoe" bends. The model predicted that the extent of anoxic waters generally mimicked the extent of the salt wedge (r2 ~ 0.65 increasing during periods of low flow and reduced following episodic high flow events. The results showed two sporadically isolated "hot spots" of anoxia, the first downstream of the horseshoe bend and the second downstream of a sill. Simulated oxygen concentrations indicated that whilst a threshold salt wedge intrusion was a requirement

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  13. Effects of nitrogen and phosphorus on the growth of Levanderina fissa: How it blooms in Pearl River Estuary

    Science.gov (United States)

    Wang, Zhaohui; Guo, Xin; Qu, Linjian; Lin, Langcong

    2017-02-01

    Effects of nitrogen (N) and phosphorus (P) from different sources and at different concentrations on the growth of Levanderina fissa (= Gyrodinium instriatum) were studied in laboratory conditions. The findings might explain the recurrent blooms of this species in Pearl River Estuary, China. Results showed that nutrient limitation significantly inhibited the growth of L. fissa. The values of specific growth rate ( μ max) and half-saturation nutrient concentration ( K S) were 0.37 divisions/d and 8.49 μmol L-1 for N, and 0.39 divisions/d and 1.99 μmol L-1 for P, respectively. Based on K S values, dissolved inorganic N level in PRE was sufficient to support the high proliferation of L. fissa, while dissolved inorganic P concentration was far lower than the minimum requirement for its effective growth. L. fissa was not able to utilize dissolved organic N (DON) compounds such as urea, amino acids, and uric acid. However, it grew well by using a wide variety of dissolved organic P (DOP) sources like nucleotides, glycerophosphate, and 4-nitrophenylphosphate. The results from this study suggested that the ability in DOP utilization of L. fissa offers this species a competitive advantage in phytoplankton communities. The high level and continuous supply of DIN, enrichment of DOP, together with warm climate and low salinity in the Pearl River Estuary provided a suitable nutrient niche for the growth of L. fissa, and resulted in the recurrent blooms in the estuary.

  14. Mesozooplankton abundance in relation to the chlorophyll maximum in the Neuse River Estuary, North Carolina, USA: Implications for trophic dynamics

    Science.gov (United States)

    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.

  15. Terrestrial input and nutrient change reflected by sediment records of the Changjiang River Estuary in recent 80 years

    Institute of Scientific and Technical Information of China (English)

    LI Junlong; ZHENG Binghui; HU Xupeng; WANG Yiming; DING Ye; LIU Fang

    2015-01-01

    A variety of environmental problems have been observed in the Changjiang River Estuary and adjacent coastal area, including eutrophication, harmful algal blooms (HABs), and hypoxia in recent decades. Application of sedimentary biogenic element indicators on the study of paleoenvironment can reconstruct environmental evolution history of waters. Two 210Pb-dated cores were collected from the Changjiang River Estuary (S3) and adjacent coastal area (Z13), and total organic carbon (TOC), total nitrogen (TN), biogenic silicon (BSi), total phosphorus (TP) and phosphorus (P) species were analyzed. Three stages of environmental changes are deduced by the nutrient sedimentary records. First, nutrient concentration increased rapidly since the 1950s, which attributed to agriculture development and overused chemical fertilizers. Second, nutrient concentration kept high and primary production began to promote during the 1960s to 1980s, while diatom abundance and proportion began to decline since the 1970s, accompanied by reduced 23SiO − concentration and flux from the river. Third, due to several dams and bridges constructed, river runoff and coastal hydrodynamic conditions reduced to a certain extent since the 1990s, which aggravated the unbal-ance in nutrient structure. Multi-nutrient proxies in sediment can reflect the natural environm-ental changes as well as influence of human activities.

  16. The level of mercury contamination in mariculture sites at the estuary of Pearl River and the potential health risk.

    Science.gov (United States)

    Tao, H C; Zhao, K Y; Ding, W Y; Li, J B; Liang, P; Wu, S C; Wong, M H

    2016-12-01

    In the present study, the Hg contamination in mariculture sites located at the estuary of Pearl River was to investigate with an attempt to analyse associated health risks of dietary exposure to both total mercury (THg) and methyl mercury (MeHg) in cultured fish and shellfish. The highest total mercury concentration (7.037 ± 0.556 ng L(-1)) of seawater was observed at Zhuhai Estuary. The Hg concentrations of sediment in Guishan Island were significantly higher (p mercury methylation mostly occurred at the sediment-water interface. Results of health risk assessments showed that fish consumption would impose a higher risk to children but less to adults, while shellfish produced in the studied area was safe for consumption.

  17. Exploration of Salt Wedge Dynamics in the Columbia River Estuary Using Optical Measurements of Internal Ship Wakes.

    Science.gov (United States)

    Holman, R. A.; Greydanus, S. J.

    2014-12-01

    In May of 2013 and beyond, Argus optical measurements of the mouth of the Columbia River estuary and plume were collected as part of the RIVET II multi-investigator field experiment. One surprise was the strength of eddy and internal wave signatures observed in movies computed from one-minute averages of high-frequency snapshots (such that gravity waves were averaged out but slicks and variable surface roughness remained). In particular, passing ships left wakes that propagated away at speeds on the order of 0.5 m/s, much slower than gravity waves and presumably surface manifestations of internal waves associated with the time-varying salt-wedge. Thus, these internal ship wakes appear to act as probes of internal stratification dynamics. This paper will explore the time variations of these internal wakes and relate them to corresponding variations in the estuary salt wedge.

  18. Phytosociology of planted and natural mangrove forests in the estuary of the Ostras River, Rio de Janeiro State, Brazil

    Directory of Open Access Journals (Sweden)

    Elaine Bernini

    2014-03-01

    Full Text Available The phytosociology of planted and natural mangrove forests were compared in the estuary of the Ostras River, Rio de Janeiro State, Brazil. Vegetation sampling was performed by the plot method, and the diameter at breast height (DBH and height of individuals > 1 m tall were recorded. The results indicated that the planted forest had lower average DBH and basal area and higher density of trunks in relation to natural forest. The distribution of individuals by height class and the distribution of stems per diameter class showed that the planted forest was younger. Laguncularia racemosa and Rhizophora mangle occurred in both forests, while Avicennia schaueriana was found only in the planted forest. Laguncularia racemosa showed greater dominance and relative density at all sites analyzed, probably because it is characteristic of sites with less marine influence and the fact that the estuary had been altered by human disturbance.

  19. Simulation of potential oyster density with variable freshwater inflow (1965-2000) to the Caloosahatchee River Estuary, southwest Florida, USA.

    Science.gov (United States)

    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

  20. Nitrous oxide in the Changjiang (Yangtze River Estuary and its adjacent marine area: Riverine input, sediment release and atmospheric fluxes

    Directory of Open Access Journals (Sweden)

    G.-L. Zhang

    2010-11-01

    Full Text Available Dissolved nitrous oxide (N2O was measured in the waters of the Changjiang (Yangtze River Estuary and its adjacent marine area during five surveys covering the period of 2002–2006. Dissolved N2O concentrations ranged from 6.04 to 21.3 nM, and indicate great temporal and spatial variations. Distribution of N2O in the Changjiang Estuary was influenced by multiple factors and the key factor varied between cruises. Dissolved riverine N2O was observed monthly at station Xuliujing of the Changjiang, and ranged from 12.4 to 33.3 nM with an average of 19.4 ± 7.3 nM. N2O concentrations in the river waters showed obvious seasonal variations with higher values occurring in both summer and winter. Annual input of N2O from the Changjiang to the estuary was estimated to be 15.0 × 106 mol/yr. N2O emission rates from the sediments of the Changjiang Estuary in spring ranged from −1.88 to 2.02 μmol m−2 d−1, which suggests that sediment can act as either a source or a sink of N2O in the Changjiang Estuary. Average annual sea-to-air N2O fluxes from the studied area were estimated to be 7.7 ± 5.5, 15.1 ± 10.8 and 17.0 ± 12.6 μmol m−2d−1 using LM86, W92 and RC01 relationships, respectively. Hence the Changjiang Estuary and its adjacent marine area are a net source of atmospheric N2O.

  1. Water Temperature, Specific Conductance, pH, and Dissolved-Oxygen Concentrations in the Lower White River and the Puyallup River Estuary, Washington, August-October 2002

    Science.gov (United States)

    Ebbert, James C.

    2003-01-01

    The U.S. Geological Survey, Washington State Department of Ecology, and Puyallup Tribe of Indians monitored water temperature, specific conductance, pH, and dissolved-oxygen concentrations in the White River at river miles 4.9 and 1.8 from August until mid-October 2002. Water diverted from the White River upstream from the monitoring sites into Lake Tapps is returned to the river at river mile 3.6 between the two sites. The same characteristics were measured in a cross section of the Puyallup River estuary at river mile 1.5 during high and low tides in September 2002. In late August, maximum daily water temperatures in the White River of 21.1oC (degrees Celsius) at river mile 4.9 and 19.6oC at river mile 1.8 exceeded the water-quality standard of 18oC at both monitoring sites. In mid-September, maximum daily water temperatures at river mile 4.9 exceeded the standard on 5 days. From August 2-25, water temperatures at both monitoring sites were similar and little or no water was discharged from Lake Tapps to the White River. Increases in water temperature at river mile 1.8 in late September and early October were caused by the mixing of warmer water discharged from Lake Tapps with cooler water in the White River. Specific conductance in the White River usually was lower at river mile 1.8 than at river mile 4.9 because of mixing with water from Lake Tapps, which has a lower specific conductance. Maximum values of pH in the White River at river mile 4.9 often exceeded the upper limit of the water-quality standard, 8.5 pH units, from early September until mid-October, when turbidity decreased. The pH standard was not exceeded at river mile 1.8. Dissolved-oxygen concentrations in the White River were often lower at river mile 1.8 than at river mile 4.9 because of mixing with water discharged from Lake Tapps, which has lower dissolved-oxygen concentrations. The lowest concentration of dissolved oxygen observed was 7.9 mg/L (milligrams per liter) at river mile 1.8. The

  2. Water temperature, specific conductance, pH, and dissolved-oxygen concentrations in the lower White River and the Puyallup River estuary, Washington, August-October 2002

    Science.gov (United States)

    Ebbert, James C.

    2003-01-01

    The U.S. Geological Survey, Washington State Department of Ecology, and Puyallup Tribe of Indians monitored water temperature, specific conductance, pH, and dissolved-oxygen concentrations in the White River at river miles 4.9 and 1.8 from August until mid-October 2002. Water diverted from the White River upstream from the monitoring sites into Lake Tapps is returned to the river at river mile 3.6 between the two sites. The same characteristics were measured in a cross section of the Puyallup River estuary at river mile 1.5 during high and low tides in September 2002. In late August, maximum daily water temperatures in the White River of 21.1°C (degrees Celsius) at river mile 4.9 and 19.6°C at river mile 1.8 exceeded the water-quality standard of 18°C at both monitoring sites. In mid-September, maximum daily water temperatures at river mile 4.9 exceeded the standard on 5 days. From August 2-25, water temperatures at both monitoring sites were similar and little or no water was discharged from Lake Tapps to the White River. Increases in water temperature at river mile 1.8 in late September and early October were caused by the mixing of warmer water discharged from Lake Tapps with cooler water in the White River.Specific conductance in the White River usually was lower at river mile 1.8 than at river mile 4.9 because of mixing with water from Lake Tapps, which has a lower specific conductance. Maximum values of pH in the White River at river mile 4.9 often exceeded the upper limit of the water-quality standard, 8.5 pH units, from early September until mid-October, when turbidity decreased. The pH standard was not exceeded at river mile 1.8. Dissolved-oxygen concentrations in the White River were often lower at river mile 1.8 than at river mile 4.9 because of mixing with water discharged from Lake Tapps, which has lower dissolved-oxygen concentrations. The lowest concentration of dissolved oxygen observed was 7.9 mg/L (milligrams per liter) at river mile 1.8. The

  3. Life history of the spottail shiner (Notropis hudsonius) in southeastern Lake Michigan, the Kalamazoo River, and western Lake Erie

    Science.gov (United States)

    Wells, LaRue; House, Robert

    1974-01-01

    In southeastern Lake Michigan spottail shiners in samples ranged from ages 0 to V, but most were in age groups I-IV. In the Kalamazoo River (a tributary of southeastern Lake Michigan) age group II was commonest in the catches, and no fish older than age IV were sampled. In western Lake Erie, most shiners were in age groups 0-II, and none were older than age IV. Mortality of males was much higher than that of females after age II in Lake Michigan and after age I in Lake Erie. Growth of spottail shiners was fastest in western Lake Erie (125 mm at the end of the third year, sexes combined) and slowest (77 mm) in the Kalamazoo River; in all three waters growth declined rapidly after the first year. Females grew faster than males.

  4. Behavior of dissolved aluminum in the Huanghe (Yellow River) and its estuary: Impact of human activities and sorption processes

    Science.gov (United States)

    Wang, Zhao-Wei; Ren, Jing-Ling; Zhang, Gui-Ling; Liu, Su-Mei; Zhang, Xiang-Zhao; Liu, Zhe; Zhang, Jing

    2015-02-01

    Dissolved aluminum (Al) is a sensitive tracer for biogeochemical cycles in the ocean. There has been a dramatic decline in water and sediment fluxes into the sea from the Huanghe because of climate change and human activities. Water-Sediment Regulation Schemes (WSRSs) have been implemented annually to flush trapped sediments from the upstream watercourse and reservoirs of the river. Monthly observations to investigate the behavior of dissolved Al in the lower reach of the Huanghe were carried out from November 2008 to December 2010. During 2009, daily observations were made to assess the impact of the ninth WSRS on the lower reach of the Huanghe and three cruises were carried out in the Huanghe Estuary in 2009 (prior to, during and following the WSRS). The monthly concentrations of dissolved Al ranged from 25 nM to 362 nM (average 90 nM) in the lower reach of the Huanghe. Assessment of the seasonal variation of dissolved Al showed that the highest concentrations occurred in summer and the lowest in winter: these corresponded to the variations in water discharge and sediment loads, which were controlled by WSRS events. During the ninth WSRS events in 2009 the daily runoff and sediment load increased from 200 m3/s to 3600 m3/s and from 0.1 g/L to 5 g/L, respectively. The concentration of dissolved Al increased from 180 nM to 600 nM (average 380 nM) in less than 20 days, which were equivalent to 43% of the annual Al flux into the Bohai. Exchange between dissolved and particulate Al, investigated using a simple sorption model based on the distribution coefficient (Kd), was approximately 106 mL/g in the Huanghe. The average concentrations of dissolved Al in the Huanghe Estuary prior to, during and following the WSRS were 243 nM, 238 nM and 186 nM, respectively. The comparable concentrations of dissolved Al in the Huanghe Estuary prior to and during the WSRS indicate that removal processes occurred in the initial stages of mixing in the estuary. The Al

  5. Contribution of priority PAHs and POPs to Ah receptor-mediated activities in sediment samples from the River Elbe Estuary, Germany.

    Science.gov (United States)

    Otte, Jens C; Keiter, Steffen; Faßbender, Christopher; Higley, Eric B; Rocha, Paula Suares; Brinkmann, Markus; Wahrendorf, Dierk-Steffen; Manz, Werner; Wetzel, Markus A; Braunbeck, Thomas; Giesy, John P; Hecker, Markus; Hollert, Henner

    2013-01-01

    The estuary of the River Elbe between Hamburg and the North Sea (Germany) is a sink for contaminated sediment and suspended particulate matter (SPM). One major concern is the effect of human activities on the hydrodynamics, particularly the intensive dredging activities in this area that may result in remobilization of sediment-bound pollutants. The aim of this study was to identify pollutants contributing to the toxicological risk associated with re-suspension of sediments in the Elbe Estuary by use of an effect-directed analysis that combines chemical and biological analyses in with specific fractionation techniques. Sediments were collected from sites along the Elbe Estuary and a site from a small harbor basin of the Elbe Estuary that is known to be polluted. The sixteen priority EPA-PAHs were quantified in organic extracts of sediments. In addition, dioxin equivalents of sediments were investigated by use of the 7-ethoxyresorufin O-deethylase assay with RTL-W1 cells and the Ah receptor-mediated luciferase transactivation assay with H4IIE-luc cells. Quantification of the 16 priority PAHs revealed that sediments were moderately contaminated at all of the sites in the Elbe River Estuary (Elbe River into its estuary. Successful identification of a significant portion of dioxin-like activity to priority PAHs in complex environmental samples such as sediments has rarely been reported.

  6. Change in Land Cover along the Lower Columbia River Estuary as Determined from Landsat Thematic Mapper (TM) Imagery, Technical Report 2003.

    Energy Technology Data Exchange (ETDEWEB)

    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

  7. 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

    Science.gov (United States)

    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.

  8. Occurrence and levels of polybrominated diphenyl ethers in surface sediments from the Yellow River Estuary, China.

    Science.gov (United States)

    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.

  9. Methane and nitrous oxide fluxes in the polluted Adyar River and estuary, SE India

    Energy Technology Data Exchange (ETDEWEB)

    Nirmal Rajkumar, A. [Institute for Ocean Management, Anna University, Chennai 600 025 (India); Barnes, J. [Ocean Research Group, School of Marine Science and Technology, Ridley Building, Newcastle University, Newcastle upon Tyne, NE1 7RU (United Kingdom); Ramesh, R.; Purvaja, R. [Institute for Ocean Management, Anna University, Chennai 600 025 (India); Upstill-Goddard, R.C. [Ocean Research Group, School of Marine Science and Technology, Ridley Building, Newcastle University, Newcastle upon Tyne, NE1 7RU (United Kingdom)], E-mail: rob.goddard@ncl.ac.uk

    2008-12-15

    We measured dissolved N{sub 2}O, CH{sub 4}, O{sub 2}, NH{sub 4}{sup +}, NO{sub 3}{sup -} and NO{sub 2}{sup -} on 7 transects along the polluted Adyar River-estuary, SE India and estimated N{sub 2}O and CH{sub 4} emissions using a gas exchange relation and a floating chamber. High NO{sub 2}{sup -} implied some nitrification of a large anthropogenic NH{sub 4}{sup +} pool. In the lower catchment CH{sub 4} was maximal (6.3 {+-} 4.3 x 10{sup 4} nM), exceeding the ebullition threshold, whereas strong undersaturation of N{sub 2}O and O{sub 2} implied intense denitrification. Emissions fluxes for the whole Adyar system {approx}2.5 x 10{sup 8} g CH{sub 4} yr{sup -1} and {approx}2.4 x 10{sup 6} g N{sub 2}O yr{sup -1} estimated with a gas exchange relation and {approx}2 x 10{sup 9} g CH{sub 4} yr{sup -1} derived with a floating chamber illustrate the importance of CH{sub 4} ebullition. An equivalent CO{sub 2} flux {approx}1-10 x 10{sup 10} g yr{sup -1} derived using global warming potentials is equivalent to total Chennai motor vehicle CO{sub 2} emissions in one month. Studies such as this may inform more effective waste management and future compliance with international emissions agreements.

  10. An Experimental Study on Major Element Release from the Sediments in the Changjiang (Yangtze River) Estuary

    Institute of Scientific and Technical Information of China (English)

    GUO Yanwei; YANG Shouye

    2015-01-01

    With the enhanced warming and acidification of global ocean, whether and to what extent the naturally-weathered fluvial sediment into the sea can release elements and thus influence the geochemical process and ecosystem of global ocean remain to be resolved. In this contribution, an experimental study was carried out to examine the release rates of major elements (Ca, K, Mg and Al) from the surface sediments in the Changjiang (Yangtze River) Estuary under the pH values of 4.0, 6.0 and 7.0. The two studied sediments consist primarily of quartz, plagioclase, calcite and clay minerals, with the BET (Brunauer, Emmett and Teller) surface areas of 61.7m2g-1 and 23.1m2g-1. Major elements of Ca, K, Mg and Al show different release rates under different solution pH values. With the decreasing solution pH, the release rates of Ca and K increase obviously, while the release rates of Mg and Al increase with the initial solution pH varying from 6.0 to 7.0. The different release rates of these elements are closely related to the original mineral composition of the sediments and the reaction kinetics. Based on the experimental observation, quartz and clay minerals that have low dissolution rates may dominate the major element release to the aqueous phase. This study reveals that the en-hancing ocean acidification could cause considerable release of major elements from natural terrigenous sediments into the ambient marine environment, which has to be considered carefully in the future study on global change.

  11. Carrying capacity for shorebirds during migratory seasons at the Jiuduansha Wetland, Yangtze River Estuary, China

    Institute of Scientific and Technical Information of China (English)

    Zhenming GE; Xiao ZHOU; Wenyu SHI; Tianhou WANG

    2008-01-01

    The carrying capacity of food resources for migrating shorebirds was estimated at a stopover site in the Yangtze River Estuary during the two migratory sea-sons (spring and autumn). From March to May and September to November 2005, the macrobenthos resources of the Jiuduansha Wetland were investigated, and most of the macrobenthos species in the newly-formed shoal were found to be appropriate food for shorebirds. Biomass measurements showed that the total food resource was about 4541.20 kg AFDW (Ash-Free Dry Weight) in spring and about 2279.64 kg AFDW in autumn. Calculations were also done in the available habi-tats (intertidal bare mudflat and Scirpus x mariqueter/ Scirpus triqueter zones) for the shorebirds. The food resources in the available areas were about 3429.03 kg AFDW in spring and about 1700.92 kg AFDW in autumn. Based on the classification (by lean weight, basic metabolic rate and body length) of the shorebird community, and using the energy depletion model, it was theorized that all of the food resources in the Jiuduansha Wetland could support about 3.5 million shorebirds during spring season and 1.75 million shorebirds during autumn season. The shorebird carrying capacities in terms of the available food were about 2.6 million and 1.3 million birds during the two respective migration seasons. Considering the effect of intake rate, the potential carrying capacity was about 0.13-0.26 million shorebirds in the study area. The main factor restricting use of the area by shorebirds was the scarcity of available habitats for roosting at high tide rather than availability of food supply. We recommend restoring some wading pools in the dense Phragmites australis and Spartina alterniflora zones for shorebirds to roost in, to improve shorebirds' utilization efficiency of the resources in the Jiuduansha Wetland.

  12. [Abundance and biomass of meiobenthos in Lingdingyang Bay of Pearl River Estuary].

    Science.gov (United States)

    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.

  13. Waterbird Population Changes in the Wetlands at Chongming Dongtan in the Yangtze River Estuary, China

    Science.gov (United States)

    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.

  14. Studies on the regional feature of organic carbon in sediments off the Huanghe River Estuary waters

    Institute of Scientific and Technical Information of China (English)

    YUAN Huamao; LIU Zhigang; SONG Jinming; L(U) Xiaoxia; LI Xuegang; LINing; ZHAN Tianrong

    2004-01-01

    Organic carbon (OC) in definitely small area sediments(according to marine dimension)offthe Huanghe River Estuary is investigated in order to evaluate the feature of regional difference of physical and chemical properties in marginal sea sediments. The distributions of OC in sediments with natural grain size and the relationship with the pH,Eh,Es and Fe3+/Fe2+ are discussed. In addition, OC decomposition rates in surfacial/subsurfacial sediments are estimated. OC concentrations range from 0.26% to 1.8%(wt)in the study area. Significant differences in OC content and in horizontal distribution as well as various trends in surfacial/subsurfacial sediments exhibit the feature of regional difference remarkably in marginal sea sediments. The complicated distribution of OC in surface sediments is due to the influence of bacterial activity and abundance, bioturbation of benthos and physical disturbance. The OC decomposition rate constant in surfacial/subsurfacial sediments ranges from 0.009 7 to 0.076 a-1 and the relatively high values may be mainly related to bacteria that are mainly responsible for OC mineralization;meio-and macrofauna affect OC degradation both directly, through feeding on it, and indirectly through bioturbation and at the same time coarse sediments are also disadvantageous to OC preservation. In almost all the middle and bottom sediments the contents of Ocdecrease with the increase of deposition depth, which indicates that mineralization of OC in the middle and bottom sediments has occurred via processes like SO2-4 reduction and Fe-oxide reduction.

  15. Cesium-137 in deer: Savannah River Plant vs. southeastern coastal plain herds

    Energy Technology Data Exchange (ETDEWEB)

    Watts, J.R.; Rabon, E.W.; Dicks, A.S.

    1979-01-01

    The /sup 137/Cs content in deer killed during programmed hunts at the Savannah River Plant (SRP) has averaged 9.0 pCi/g. This value, based on measurements of 13,907 deer taken over 14 years (1965 to 1978), similar to the value obtained for 552 deer from other southeastern Coastal Plain locations, indicating the /sup 137/Cs content is due to fallout from the atmospheric testing of nuclear weapons rather than from SRP operations. The computerized SRP data base for each harvested deer includes age, sex, weight, cesium content, kill location, date, and the hunter's name. Analysis of these data enables the estimation of population dose from ingestion of the edible meat. Consumption of all edible meat from deer killed at SRP from 1965 to 1978 gives a whole body population dose of 196 man-rem from /sup 137/Cs. Assuming an annual consumption rate of 20 kg gives an average individual whole body dose of 13 mrem, about 10% of local annual background level. The radiation dose from /sup 40/K of natural potassium content of deer is comparable to the radiation dose from /sup 137/Cs.

  16. Zooplankton spatial and diurnal variations in the Changjiang River estuary before operation of the Three Gorges Dam

    Institute of Scientific and Technical Information of China (English)

    GAO Xuelu; SONG Jinming; LI Xuegang

    2011-01-01

    Estuarine plankton communities can serve as indicators of ecosystem modification in response to anthropogenic influences. The main objectives of this study were to describe the spatial distribution and diurnal variability in zooplankton abundance and biomass over almost entire salinity gradient of the Changjiang (Yangtze) River estuary and to provide a background reference for future studies. To accomplish this, data were collected from 29 stations in the estuary from May 19 to 26, 2003,including two anchor stations. The spatial and diurnal variations in zooplankton characteristics, i.e.abundance, biomass, and gross taxonomic composition, were examined. Generally, both the abundance and biomass gradually increased seaward and presented distinct spatial variations. In addition, the spatial data revealed a significant correlation between abundance and biomass; however, there was no significant correlation between abundance and biomass for the diurnal data. Although the zooplankton composition indicated distinct spatial differences in terms of dominant groups, copepods accounted for >50% of the total zooplankton abundance in most regions and times. Three zooplankton assemblages were recognized through hierarchical cluster analysis. These assemblages existed along the salinity gradient from fresh water to seawater, and their positions coincided with those of the three principal water masses in the estuary. The assemblages were classified as: (1) true estuarine, (2) estuarine and marine, and (3) euryhaline marine, which were characterized by the copepods Sinocalanus dorrii, Labidocera euchaeta, and Calanus sinicus, respectively. Both spatial and diurnal data indicated that there was no significant correlation between zooplankton abundance/biomass and depth-integrated phytoplankton abundance.

  17. Spatial and vertical distribution of bacteria in the Pearl River estuary ...

    African Journals Online (AJOL)

    Yomi

    2012-01-31

    Jan 31, 2012 ... transported, stored, and modified in estuaries, a buffer zone where ... techniques; and (3) Assess the impacts of environmental changes such as nutrient ..... ammonia-oxidizing bacteria correlates with increasing salinity in an.

  18. Nutrient characterisation of river inflow into the estuaries of the Gouritz Water Management Area, South Africa

    CSIR Research Space (South Africa)

    Lemley, DA

    2014-10-01

    Full Text Available cycling (Buzzelli et al., 2007; Buzzelli, 2012). A great deal of emphasis has been placed on determining the consequences of these anthropogenic stressors on estuaries through the use of monitoring programmes (Carstensen et al., 2012). In South Africa... systems. Assessing the effectiveness and compliance of WWTPs is essential to providing a complete and holis- tic overview of water quality inputs into the estuaries of the Gouritz WMA. Effluents from WWTPs are discharged to sur- face waters, after...

  19. Aquifer responses to climate anomalies in the Loddon River catchment, Southeastern Australia

    Science.gov (United States)

    Manamperi, S.; Webb, J.

    2013-12-01

    Numerous studies suggest that climate change will lead to changes in the seasonality of surface water availability, thereby changing the recharge pattern in groundwater aquifers. Climate modelling predicts an increasing trend of extreme events such as floods and droughts in much of Southeastern Australia in the future. The present study provides a long-term compilation and analysis of the water table response to the last 30 years of climate in the Loddon River catchment, southeastern Australia, in order to evaluate the underlying mechanisms, and determine the response of the Loddon aquifers to past and future climate variability. There are three main aquifers in the catchment (Newer Volcanics, Shepparton Formation and Calivil Formation, in stratigraphic order). Using 215 groundwater monitoring bores with 10 or more years of data, coupled with 8 stream gauges and 8 rainfall gauging stations, several statistical analyses were performed. The monitoring bore data was used to define 7 different hydrogeomorphic units based on topography and aquifer characteristics. Groundwater trends were calculated as normalized anomalies (difference from the mean / standard deviation) and compared to regional rainfall and stream flow anomalies, to understand the sensitivity of the aquifer systems to change. Changes in groundwater storage during the periods that show a significantly high anomaly were calculated using the water level fluctuation method. Results suggest that, regionally, the Loddon aquifers respond strongly to episodic flooding events and decade-long droughts. The highest anomalies in each data set were observed during 2010/11, the highest recorded river flow and rainfall in the last 30 years, accompanied by extensive flooding in the Lower Loddon. However, the aquifers in the Lower Loddon show diverse trends in water level response to this event. The shallow Shepparton Formation aquifer showed a rapid response to flooding with a decreasing trend after few months, whereas

  20. Holocene stratigraphy of the Ångermanälven River estuary, Bothnian Sea

    Science.gov (United States)

    Hyttinen, O.; Kotilainen, A. T.; Virtasalo, J. J.; Kekäläinen, P.; Snowball, I.; Obrochta, S.; Andrén, T.

    2017-06-01

    This study explores the Holocene depositional succession at the IODP Expedition 347 sites M0061 and M0062 in the vicinity of the Ångermanälven River estuary in the Bothnian Sea sector of the Baltic Sea in northern Scandinavia. Site M0061 is located in a coastal offshore setting (87.9 m water depth), whereas site M0062 is fully estuarine (69.3 m water depth). The dataset comprises acoustic profiles and sediment cores collected in 2007 and late 2013 respectively. Three acoustic units (AUs) were recognized. Lowermost AU1 is interpreted as a poorly to discontinuous stratified glaciofluvial deposit, AU2 as a stratified conformable drape of glaciolacustrine origin, and AU3 as a poorly stratified to stratified mud drift. A strong truncating reflector separates AU2 and AU3. Three lithological units (LUs) were defined in the sediment cores. LU1 consists of glaciofluvial sand and silt gradating into LU2, which consists of glaciolacustrine varves. A sharp contact interpreted as a major unconformity separates LU2 from the overlying LU3 (brackish-water mud). In the basal part of LU3, one debrite (site M0061) or two debrites (site M0062) were recognized. Information yielded from sediment physical properties (magnetic susceptibility, natural gamma ray, dry bulk density), geochemistry (total carbon, total organic carbon, total inorganic carbon and nitrogen), and grain size support the LU division. The depositional succession was formally subdivided into two alloformations: the Utansjö Alloformation and overlying Hemsön Alloformation; the Utansjö Alloformation was further subdivided into two lithostratigraphic formations: the Storfjärden and Åbordsön formations. The Storfjärden (sandy outwash) and Åbordsön (glaciolacustrine rhythmite) formations represent a glacial retreat systems tract, which started at ca. 10.6 kyr BP. Their deposition was mainly controlled by meltwater from the retreating ice margin, glacio-isostatic land uplift and the regressive (glacial) lake level

  1. Holocene stratigraphy of the Ångermanälven River estuary, Bothnian Sea

    Science.gov (United States)

    Hyttinen, O.; Kotilainen, A. T.; Virtasalo, J. J.; Kekäläinen, P.; Snowball, I.; Obrochta, S.; Andrén, T.

    2016-12-01

    This study explores the Holocene depositional succession at the IODP Expedition 347 sites M0061 and M0062 in the vicinity of the Ångermanälven River estuary in the Bothnian Sea sector of the Baltic Sea in northern Scandinavia. Site M0061 is located in a coastal offshore setting (87.9 m water depth), whereas site M0062 is fully estuarine (69.3 m water depth). The dataset comprises acoustic profiles and sediment cores collected in 2007 and late 2013 respectively. Three acoustic units (AUs) were recognized. Lowermost AU1 is interpreted as a poorly to discontinuous stratified glaciofluvial deposit, AU2 as a stratified conformable drape of glaciolacustrine origin, and AU3 as a poorly stratified to stratified mud drift. A strong truncating reflector separates AU2 and AU3. Three lithological units (LUs) were defined in the sediment cores. LU1 consists of glaciofluvial sand and silt gradating into LU2, which consists of glaciolacustrine varves. A sharp contact interpreted as a major unconformity separates LU2 from the overlying LU3 (brackish-water mud). In the basal part of LU3, one debrite (site M0061) or two debrites (site M0062) were recognized. Information yielded from sediment physical properties (magnetic susceptibility, natural gamma ray, dry bulk density), geochemistry (total carbon, total organic carbon, total inorganic carbon and nitrogen), and grain size support the LU division. The depositional succession was formally subdivided into two alloformations: the Utansjö Alloformation and overlying Hemsön Alloformation; the Utansjö Alloformation was further subdivided into two lithostratigraphic formations: the Storfjärden and Åbordsön formations. The Storfjärden (sandy outwash) and Åbordsön (glaciolacustrine rhythmite) formations represent a glacial retreat systems tract, which started at ca. 10.6 kyr BP. Their deposition was mainly controlled by meltwater from the retreating ice margin, glacio-isostatic land uplift and the regressive (glacial) lake level

  2. Modeling the mass flux budgets of water and suspended sediments for the river network and estuary in the Pearl River Delta, China

    Science.gov (United States)

    Hu, Jiatang; Li, Shiyu; Geng, Bingxu

    2011-11-01

    A coupled physical and sediment transport model was used to study the mass flux budgets of water and suspended sediments in the Pearl River Delta (PRD). The coupled model incorporates the Pearl River network, the Pearl River Estuary (PRE) and adjacent coastal waters in one overall modeling system. The results indicate that the river network and the PRE both have pronounced temporal and spatial variability in water and sediment fluxes, in hydrodynamic features and in sediment depositional patterns. In the river network, the riverine fluxes of water and suspended sediments are dominated by the West River, and those that are exported to the PRE (defined as the estuarine fluxes) are primarily contributed by Modaomen. The river outlets are highly responsive to the main tributaries in terms of water and sediment fluxes, revealing a close coupling between the upstream and the downstream boundaries. Most of the annual riverine and estuarine fluxes occur in the wet season, approximately 74% of the water flux and riverine and estuarine fluxes of suspended sediments of 94% and 87%, respectively. Although the water and sediment transport is dominated by river discharge, the tides are also an important factor, especially in regulating the structures of seasonal deposits in the river network (deposition in the wet season and erosion in the dry season). In the PRE, various types of physical forcing, including river discharge, monsoon winds, tides, coastal currents and the gravitational circulation associated with a density gradient, operate in concert to control the water and sediment transport in the estuary. Most of the oceanic fluxes of water and suspended sediments entering the South China Sea take place in the dry season and are primarily conveyed by strong western coastal currents. The PRE is a sedimentary system characterized by intricate depositional structures in space and time. Several depositional patterns and the associated driving mechanisms were identified. A fan

  3. Impact of flood events on macrobenthic community structure on an intertidal flat developing in the Ohta River Estuary.

    Science.gov (United States)

    Nishijima, Wataru; Nakano, Yoichi; Nakai, Satoshi; Okuda, Tetsuji; Imai, Tsuyoshi; Okada, Mitsumasa

    2013-09-15

    We investigated the effects of river floods on the macrobenthic community of the intertidal flat in the Ohta River Estuary, Japan, from 2005 to 2010. Sediment erosion by flood events ranged from about 2-3 cm to 12 cm, and the salinity dropped to 0‰ even during low-intensity flood events. Cluster analysis of the macrobenthic population showed that the community structure was controlled by the physical disturbance, decreased salinity, or both. The opportunistic polychaete Capitella sp. was the most dominant species in all clusters, and populations of the long-lived polychaete Ceratonereis erythraeensis increased in years with stable flow and almost disappeared in years with intense flooding. The bivalve Musculista senhousia was also an important opportunistic species that formed mats in summer of the stable years and influenced the structure of the macrobenthic community. Our results demonstrate the substantial effects of flood events on the macrobenthic community structure.

  4. A Synthesis of Environmental and Plant Community Data for Tidal Wetland Restoration Planning in the Lower Columbia River and Estuary

    Energy Technology Data Exchange (ETDEWEB)

    Diefenderfer, Heida L.; Borde, Amy B.; Cullinan, Valerie I.

    2013-12-01

    This report reanalyzes and synthesizes previously existing environmental and plant community data collected by PNNL at 55 tidal wetlands and 3 newly restored sites in the lower Columbia River and estuary (LCRE) between 2005 and 2011. Whereas data were originally collected for various research or monitoring objectives of five studies, the intent of this report is to provide only information that will have direct utility in planning tidal wetland restoration projects. Therefore, for this report, all tidal wetland data on plants and the physical environment, which were originally developed and reported by separate studies, were tabulated and reanalyzed as a whole. The geographic scope of the data collected in this report is from Bonneville Lock and Dam to the mouth of the Columbia River

  5. Seasonal distribution and geochemical fractionation of heavy metals from surface sediment in a tropical estuary of Jeneberang River, Indonesia.

    Science.gov (United States)

    Najamuddin; Prartono, Tri; Sanusi, Harpasis S; Nurjaya, I Wayan

    2016-10-15

    Lead (Pb) and zinc (Zn) concentrations from surface sediments were determined at 17 stations in riverine, estuarine, and marine environments during the wet and dry seasons. The geochemical fractionations were obtained by a sequential extraction procedure in five geochemical forms: exchangeable, bound to carbonate, iron-manganese oxide, organic, and residual fractions. The concentrations of Pb and Zn in the water were higher during the wet season than the dry season and higher in the riverine and marine samples than the estuarine samples. Following geochemical fractionation, the metals were found mainly in the residual fraction. The results indicated that the concentrations were influenced by season, with the sources of Pb and Zn derived mainly from rivers and natural sources. The contamination status in the estuary of the Jeneberang River was classified as weak to moderate pollution and the risk level to aquatic biota attributed was no risk to low risk.

  6. Evaluating Cumulative Ecosystem Response to Restoration Projects in the Columbia River Estuary, Annual Report 2004

    Energy Technology Data Exchange (ETDEWEB)

    Diefenderfer, Heida L.; Roegner, Curtis; Thom, Ronald M.; Dawley, Earl M.; Whiting, Allan H.; Johnson, Gary E.; Sobocinski, Kathryn L.; Anderson, Michael G.; Ebberts, Blaine

    2005-12-15

    indicators for detecting a signal in the estuarine system resulting from the multiple projects were also reviewed, i.e. organic matter production, nutrient cycling, sedimentation, food webs, biodiversity, salmon habitat usage, habitat opportunity, and allometry. In subsequent work, this information will be used to calculate the over net effect on the ecosystem. To evaluate the effectiveness of habitat restoration actions in the lower Columbia River and estuary, a priority of this study has been to develop a set of minimum ecosystem monitoring protocols based on metrics important for the CRE. The metrics include a suite of physical measurements designed to evaluate changes in hydrological and topographic features, as well as biological metrics that will quantify vegetation and fish community structure. These basic measurements, intended to be conducted at all restoration sites in the CRE, will be used to (1) evaluate the effectiveness of various restoration procedures on target metrics, and (2) provide the data to determine the cumulative effects of many restoration projects on the overall system. A protocol manual is being developed for managers, professional researchers, and informed volunteers, and is intended to be a practical technical guide for the design and implementation of monitoring for the effects of restoration activities. The guidelines are intended to standardize the collection of data critical for analyzing the anticipated ecological change resulting from restoration treatments. Field studies in 2005 are planned to initiate the testing and evaluation of these monitoring metrics and protocols and initiate the evaluation of higher order metrics for cumulative effects.

  7. Surficial and vertical distribution of heavy metals in different estuary wetlands in the Pearl river, South China

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Honggang; Cui, Baoshan [State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Beijing Normal University, Beijing (China); Zhang, Kejiang [Xinjiang Research Center of Water and Wastewater Treatment, Xinjiang Deland Co., LTD., Urumqi (China)

    2012-10-15

    A total of 87 soil profiles sampled from five types of wetlands in the Pearl River estuary were analyzed to investigate the surficial and vertical distributions of heavy metals (Cd, Cr, Cu, Ni, Pb, and Zn). The results show that wetlands directly connected with rivers (e.g., riparian wetlands, estuarine wetlands, and mangrove wetlands) has much higher metal concentrations than those indirectly connected with rivers (e.g., pond wetlands and reclaimed wetlands). The river water is the major pollution source for all investigated heavy metals. The vertical distribution of heavy metals can be classified into three patterns: (i) linear distribution pattern. The concentration of heavy metals gradually decreases with an increase in soil depth (for riparian and estuarine wetlands); (ii) irregular and stable pattern (for pond and reclaimed wetlands); and (iii) middle enrichment pattern (for mangrove wetlands). In addition to river-borne inputs, a variety of vegetation composition, hydraulic conditions, and human activities also contribute to the variation in distribution of heavy metals in different wetlands. Soil properties (e.g., particle size, pH, salinity, and SOM) also affect the distribution of trace metals in each soil layer. The major pollution source of heavy metals is industrial wastewater. Other sources include agriculture and domestic premises, and atmospheric deposition. This study provides a sound basis for the risk assessment of heavy metals in the studied wetlands and for wetland conservation in general. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Assessment of Soil Water Content in Field with Antecedent Precipitation Index and Groundwater Depth in the Yangtze River Estuary

    Institute of Scientific and Technical Information of China (English)

    XIE Wen-ping; YANG Jing-song

    2013-01-01

    To better understand soil moisture dynamics in the Yangtze River Estuary (YRE) and predict its variation in a simple way, a field monitoring experiment was carried out along the north branch of the Yangtze River, where seawater intrusion was strong and salt-water variation is one of the limiting factors of local agriculture. In present paper, relation between antecedent precipitation index (API) and soil water content is studied, and effects of groundwater depth on soil water content was analyzed. A relatively accurate prediction result of soil water content was reached using a neural network model. The impact analysis result showed that the variation of the API was consistent with soil water content and it displayed significant correlations with soil water content in both 20 and 50 cm soil layer, and higher correlation was observed in the layer of 20 cm. Groundwater impact analysis suggested that soil moisture was affected by the depth of groundwater, and was affected more greatly by groundwater at depth of 50 cm than that at 20 cm layer. By introducing API, groundwater depth and temperature together, a BP artificial network model was established to predict soil water content and an acceptable agreement was achieved. The model can be used for supplementing monitoring data of soil water content and predicting soil water content in shallow groundwater areas, and can provide favorable support for the research of water and salt transport in estuary area.

  9. A preliminary investigation on genetic diversity of Sousa chinensis in the Pearl River Estuary and Xiamen of Chinese waters

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In this study, the mitochondrial DNA (mtDNA) control region and the mitochondrial cytochrome b gene of stranded Indo-Pacific humpback dolphin (Sousa chinensis) samples from the Pearl River Estuary and Xiamen waters were sequenced and analyzed. The result of mtDNA control region revealed 34 variable sites and four unique haplotypes (named as A, B, C and D) identified among the total samples from these two water areas, and the most common haplotype (A) was shared by 75% of the dolphins sampled from the two water areas. The haplotypic diversity (h) was 0.455 and the nucleotide diversity (π) was 0.0088. The phylogenetic analysis showed that the haplotype A, C, and D were closely related, but the haplotype B (unique for XM01 from Xiamen) was far from the other three. By scanning cytochrome b fragments, two haplotypes (A and B) were identified in these two water areas, and the most common haplotype (A) was shared by 91.67% individuals, while XM01 from Xiamen as the only exception. The date suggest that there is a possibility of gene exchange between the two populations in the Pearl River Estuary and Xiamen waters, and there possibly exists a unique maternal lineage in Xiamen waters.

  10. First occurrence of thinlip grey mullet, Liza ramada (Risso, 1827 in the Odra River estuary (NW Poland: genetic identification

    Directory of Open Access Journals (Sweden)

    Remigiusz Panicz

    2016-07-01

    Full Text Available The presence of exotic fish species in the Baltic Sea and its tributaries poses a serious threat for native ichthyofauna, mainly due to the spread of new pathogens. As the accurate identification of species is essential for an effective assessment of changes related to the appearance of non-native species in an aquatic environment, in this paper we tested the usefulness of biometrics and molecular markers in identifying a specimen from the Mugilidae family found in the Odra estuary. The results demonstrated that unambiguous identification of the specimen using biometric features was impossible due to high morphological similarities shared by grey mullets. Unambiguous identification was possible only due to molecular markers, e.g. rhodopsin gene, which helped to identify the collected fish specimen as Liza ramada (Risso, 1827, the first specimen of this species found in the Odra River estuary. The presence of an L. ramada specimen in the Odra River – which could signal the expansion of non-native species into wider ranges – may be linked to climate change or human activity.

  11. The Accumulation and Seasonal Dynamic of the Soil Organic Carbon in Wetland of the Yellow River Estuary, China

    Directory of Open Access Journals (Sweden)

    Xianxiang Luo

    2014-01-01

    Full Text Available The wetland of the Yellow River estuary is a typical new coastal wetland in northern China. It is essential to study the carbon pool and its variations for evaluating the carbon cycle process. The study results regarding the temporal-spatial distribution and influential factors of soil organic carbon in four typical wetlands belonging to the Yellow River estuary showed that there was no significant difference in the contents of the surface soil TOC to the same season among the four types of wetlands. For each type of wetlands, the TOC content in surface soils was significantly higher in October than that in both May and August. On the whole, the obvious differences in DOC contents in surface soils were not observed in the different wetland types and seasons. The peak of TOC appeared at 0–10 cm in the soil profiles. The contents of TOC and DOC were significantly higher in salsa than those in reed, suggesting that the rhizosphere effect of organic carbon in salsa was more obvious than that in reed. The results of the principal component analysis showed that the nitrogen content, salinity, bulk density, and water content were dominant influential factors for organic carbon accumulation and seasonal variation.

  12. Environmental monitoring and assessment of heavy metals in surface sediments at Coleroon River Estuary in Tamil Nadu, India.

    Science.gov (United States)

    Venkatramanan, S; Chung, S Y; Ramkumar, T; Selvam, S

    2015-08-01

    The combined studies on grain size distribution, organic matter contents of sediments, sequential extraction and bulk concentration of heavy metals, statistical analysis, and ecological risk assessments were carried out to investigate the contamination sources and ecological risks of surface sediments at Coleroon River Estuary in Tamil Nadu, India. The sequential extraction of metals showed that a larger portion of the metals was associated with the residual phase and also in other fractions. The low concentrations of heavy metals were found in exchangeable and carbonate bounds (bioavailable phases). It revealed that sediments of Coleroon River Estuary were relatively unpolluted and were influenced mainly by natural sources. The observed order of bulk concentrations of heavy metals in the sediments was as follows: Fe > Mn > Zn > Cu > Pb > Cr > Ni > Co. Factor analyses represented that the enrichment of heavy metals was mostly resulted from lithogenic origins associated with anthropogenic sources. These sources were reconfirmed by cluster analysis. Risk assessment code (RAC) suggested that all metals were not harmful in monsoon season. However, Fe was in medium risk, and Mn and Cu were in low risk in summer. According to pollution load index (PLI) of sediments, all heavy metals were toxic. Cu might be related with adverse biological effects on the basis of sediment quality guidelines (SQG) in both seasons. These integrated approaches were very useful to identify the contamination sources and ecological risks of sediments in estuarine environment. It is expected that this research can give a useful information for the remediation of heavy metals in sediments.

  13. [Study on dynamics of hydrogen sulfide and carbonyl sulfide emission fluxes from Suaeda salsa marsh in the Yellow River estuary].

    Science.gov (United States)

    Li, Xin-Hua; Guo, Hong-Hai; Yang, Li-Ping; Zhu, Zhen-Lin; Sun, Xiao-Qing

    2014-02-01

    The H2S and COS emission fluxes from Suaeda salsa marsh in the Yellow River estuary were measured using the static chamber and Chromatogram method during the growth season (May to October), the results showed that the seasonal and diurnal variations of H2S and COS emission fluxes were obvious, and Suaeda salsa marsh in the Yellow River estuary was the sources for both H2S and COS during the growth time, and the mean H2S and COS emission fluxes from Suaeda salsa marsh were 4.97 microg x (m2 x h)(-1) and 0.92 microg x (m2 x h)(-1), respectively. Different environmental factors had different effects on the emission fluxes of H2S and COS from Suaeda salsa marsh, in which the SO4(2-) content and water content in the soil were the main factors that affected the H2S and COS emission fluxes, respectively. Sulfur gases emissions from Suaeda salsa marsh may be affected by many factors, such as plant, tide status and so on, so that should be further studied.

  14. Reservoir impacts downstream in highly regulated river basins: the Ebro delta and the Guadalquivir estuary in Spain

    Science.gov (United States)

    Polo, María J.; Rovira, Albert; García-Contreras, Darío; Contreras, Eva; Millares, Agustín; Aguilar, Cristina; Losada, Miguel A.

    2016-05-01

    Regulation by reservoirs affects both the freshwater regime and the sediment delivery at the area downstream, and may have a significant impact on water quality in the final transitional water bodies. Spain is one the countries with more water storage capacity by reservoirs in the world. Dense reservoir networks can be found in most of the hydrographic basins, especially in the central and southern regions. The spatial redistribution of the seasonal and annual water storage in reservoirs for irrigation and urban supply, mainly, has resulted in significant changes of water flow and sediment load regimes, together with a fostered development of soil and water uses, with environmental impacts downstream and higher vulnerability of these areas to the sea level rise and drought occurrence. This work shows these effects in the Guadalquivir and the Ebro River basins, two of the largest regulated areas in Spain. The results show a 71 % decrease of the annual freshwater input to the Guadalquivir River estuary during 1930-2014, an increase of 420 % of the irrigated area upstream the estuary, and suspended sediment loads up to 1000 % the initial levels. In the Ebro River delta, the annual water yield has decreased over a 30 % but, on the contrary, the big reservoirs are located in the main stream, and the sediment load has decreased a 99 %, resulting in a delta coastal regression up to 10 m per year and the massive presence of macrophytes in the lower river. Adaptive actions proposed to face these impacts in a sea level rise scenario are also analyzed.

  15. Tsunami hazard assessment in the Hudson River Estuary based on dynamic tsunami-tide simulations

    Science.gov (United States)

    Shelby, Michael; Grilli, Stéphan T.; Grilli, Annette R.

    2016-12-01

    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

  16. [Faunal characteristics and distribution pattern of crustaceans in the vicinity of Pearl River estuary].

    Science.gov (United States)

    Huang, Zi-Rong; Sun, Dian-Rong; Chen, Zuo-Zhi; Zhang, Han-Hua; Wang, Xue-Hui; Wang, Yue-Zhong; Fang, Hong-Da; Dong, Yan-Hong

    2009-10-01

    Based on the data of bottom trawl surveys in the vicinity of Pearl River estuary in August (summer), October (autumn), December (winter) 2006, and April (spring) 2007, the faunal characteristics and distribution pattern of crustaceans were analyzed. A total of 54 species belonging to 25 genera, 17 families, and 2 orders were collected, including 22 species of shrimps, 22 species of crabs, and 10 species of squills. Most of the crustaceans were tropical-subtropical warm-water species, a few of them were eurythermal species, and no warm-water and cold-water species occurred. Euryhaline species were most abundant, followed by halophile species, and the low-salinity species were the least. Most of the crustacean species belonged to the fauna of Indian Ocean-western Pacific Ocean. The faunal assemblages were closer to those of the East China Sea, Philippine Sea, Indonesia Sea, and the Japan Sea, and estranger with those of the Yellow Sea, Bohai Sea, and Korea Sea. The dominant species were Metapenaeus joyner, Oratosquilla oratoria, Charybdis miles, Portunus sanguinolentus, Harpiosquilla harpax, Charybdis feriatus, Charybdis japonica, Oratosquilla nepa, Solenocera crassicornis, Portunus trituberculatus, and Calappa philargius. The crustaceans had the largest species number (33) in autumn and the least one (26) in spring, and the highest stock density at the water depth of < 40 m, especially at 10-20 m. The average stock density of the crustaceans was estimated to be 99.60 kg x km(-2), with the highest (198.93 kg x km(-2)) in summer and the lowest (42.35 kg x km(-2)) in spring. Of the 3 species groups, crabs had the highest stock density (41.81 kg x km(-2)), followed by shrimps (38.91 kg x km(-2)), and squills (18.88 kg x km(-2)). The stock densities of the 3 species groups showed an obvious seasonal variation. Shrimps had the highest stock density (120.32 kg x km(-2)) in summer and the lowest density (0.67 kg x km(-2)) in spring, while crabs and squills had the highest

  17. Regional patterns of particulate spectral absorption in the Pearl River estuary

    Institute of Scientific and Technical Information of China (English)

    CAO Wenxi; YANG Yuezhong; XU Xiaoqiang; HUANG Liangmin; ZHANG Jianlin

    2003-01-01

    Spectral absorption coefficients of the total particulate, ap(λ), nonalgal particulate, ad(λ), and phytoplankton pigment, aph(λ), in the Pearl River estuary and its vicinity waters were determined using the quantitative filter technique. The particulate absorption ap(443) ranged from 0.04 to 1.82 m-1, withthe corresponding aph(443) ranging from 0.016 to 0.484 m-1. Two typical spectral patterns are found for the total particulate absorption. For the first typicalspectral pattern, the total particulate absorption spectra are similar to that of nonalgal particulate, with values of absorption coefficient decreasing with wavelength. In contrast, for the second spectral pattern the spectral absorptionsby total particulate are very similar to that of phytoplankton pigment. The spectral dependency of absorption by nonalgal particulate follows an exponential increase toward short wavelengths, with an average slope of 0.012±0.002 nm-1. Thenonalgal absorption and the fraction of the nonalgal particulate absorption to the total particulate absorption exhibit a distinct trend of decreasing with salinity of the surface water. Phytoplankton pigment absorption exhibits a clear trend of increasing nonlinearly with chlorophyll a concentration. The relationships between the phytoplankton pigment absorption and chlorophyll a concentration can be described by power law, with the determination coefficient r2 of 0.82. Butonly weak relationships between ap(λ) and chlorophyll a concentration are observed, with the determination coefficient r2 of 0.42. The relatively large scatter around ap(443) versus chl-a relationship would be attributed to the effects ofloading of the nonalgal particulate absorption. Our analysis indicated that such relationships similar to that for Case Ⅰ waters can be applicable to optically complex Case Ⅱ waters if the effects caused by nonalgal are corrected. The chlorophyll-specific absorption coefficients of phytoplankton pigment are not constant, it

  18. Variations in light absorption properties during a phytoplankton bloom in the Pearl River estuary

    Science.gov (United States)

    Wang, Guifen; Cao, Wenxi; Yang, Yuezhong; Zhou, Wen; Liu, Sheng; Yang, Dingtian

    2010-05-01

    From 15 to 28 August in 2007, a Chaetoceros socialis bloom was detected in the Pearl River Estuary water with chlorophyll a concentration (Chl a) up to 30 mg m -3 and cell density up to 10 6 cells L -1. Time series of bio-optical measurements was obtained at a single site (114.29°E, 22.06°N) with the mooring of marine optical buoy. Light absorption properties of seawater experienced large variability throughout the algal bloom. Absorption by colored dissolved organic matter (CDOM) was one of the dominant optical components of the light absorption (30-70%) especially for pre- and post-bloom waters, and it tended to decrease with Chl a during the algal bloom. Absorption by phytoplankton was another dominant optical component (18-50%) and increased rapidly with Chl a. Phytoplankton and accompanying material played dominant roles in light absorption as indicated by the relationship between absorption coefficient and Chl a. At high pigment concentrations, water samples showed significantly lower specific phytoplankton absorption, compared with pre- and post-bloom conditions, with the specific phytoplankton concentration at 443 nm varied between 0.011 and 0.022 m 2 mg -1 and that at 676 nm between 0.007 and 0.018 m 2 mg -1; small values of blue-to-red ratio of phytoplankton were also observed. These lower values were associated with variations in phytoplankton size structure. Spectral variability of phytoplankton absorption and total absorption (not including the fixed background absorption by pure water itself) could be expressed as simple linear functions linking absorption at one wavelength to the absorption at the other wavelengths, with the slope of the relationship changing with wavelength. The absorption coefficients by non-algal particles and CDOM follow the general exponential functions with remarkably limited variability in the exponent with means of 0.0105 and 0.0166 nm -1, respectively. These spectral dependencies of absorption coefficients provide useful

  19. Learning Lessons from Estuaries

    Science.gov (United States)

    Schnittka, Christine

    2006-01-01

    There is something that draws all people to the sea and especially to the fertile estuaries that nuzzle up to its shores. An estuary serves as both a nursery and a grave for sea creatures. If life evolved from some primordial sea, it may well have been an estuary--a place where ocean and rivers meet and fresh and salty waters mingle in the…

  20. Solute transport into the Jiulong River estuary via pore water exchange and submarine groundwater discharge: New insights from 224Ra/228Th disequilibrium

    Science.gov (United States)

    Hong, Qingquan; Cai, Pinghe; Shi, Xiangming; Li, Qing; Wang, Guizhi

    2017-02-01

    Pore water exchange (PEX) and submarine groundwater discharge (SGD) represent two mechanisms for solute transport from the seabed into the coastal ocean. However, their relative importance remains to be assessed. In this study, we pursued the recently developed 224Ra/228Th disequilibrium approach to quantify PEX fluxes of 224Ra into the Jiulong River estuary, China. By constructing a full mass balance of water column 224Ra, we were allowed to put various source terms, i.e., SGD, diffusive and advective pore water flow (PEX), and river input in a single context. This led to the first quantitative assessment of the relative importance of PEX vs. SGD in the delivery of solutes into an estuary. We carried out two surveys in the Jiulong River estuary: one in January 2014 (winter survey), the other in August 2014 (summer survey). By virtue of a 1-D mass balance model of 224Ra in the sediment column, we demonstrated that PEX fluxes of 224Ra were highly variable, both temporally and spatially, and can change by 1-2 orders of magnitude in our study area. Moreover, we identified a strong correlation between 224Ra-based irrigation rate and 234Th-based sediment mixing rate. Our results highlighted irrigation as the predominant PEX process for solute transfer across the sediment-water interface. Total PEX flux of 224Ra (in 1010 dpm d-1) into the Jiulong River estuary was estimated to be 22.3 ± 3.0 and 33.7 ± 5.5 during the winter and summer surveys, respectively. In comparison, total SGD flux of 224Ra (in 1010 dpm d-1) was 11.3 ± 8.6 and 49.5 ± 16.3 in the respective seasons. By multiplying the PEX fluxes of 224Ra by the ratio of the concentration gradients of component/224Ra at the sediment-water interface, we quantified the total PEX fluxes of dissolved inorganic carbon (DIC) and nutrients (NH4+, NO3-, and H4SiO4) into the Jiulong River estuary. In the meantime, net export of DIC and nutrients via SGD were estimated by multiplying the SGD fluxes of 224Ra by the DIC

  1. Eelgrass Enhancement and Restoration in the Lower Columbia River Estuary, Period of Performance: Feb 2008-Sep 2009.

    Energy Technology Data Exchange (ETDEWEB)

    Judd, C.; Thom, R; Borde, A. [Pacific Northwest National Laboratory

    2009-09-08

    The purpose of this study was to evaluate the ability to enhance distribution of eelgrass (Zostera marina) in the Columbia River Estuary to serve as refuge and feeding habitat for juvenile salmon, Dungeness crab, and other fish and wildlife. We strongly suspected that limited eelgrass seed dispersal has resulted in the present distribution of eelgrass meadows, and that there are other suitable places for eelgrass to survive and form functional meadows. Funded as part of the Bonneville Power Administration's call for Innovative Projects, we initiated a multistage study in 2008 that combined modeling, remote sensing, and field experimentation to: (1) Spatially predict habitat quality for eelgrass; (2) Conduct experimental plantings; and (3) Evaluate restoration potential. Baseline in-situ measurements and remote satellite observations were acquired for locations in the Lower Columbia River Estuary (LCRE) to determine ambient habitat conditions. These were used to create a habitat site-selection model, using data on salinity, temperature, current velocity, light availability, wave energy, and desiccation to predict the suitability of nearshore areas for eelgrass. Based on this model and observations in the field, five sites that contained no eelgrass but appeared to have suitable environmental conditions were transplanted with eelgrass in June 2008 to test the appropriateness of these sites for eelgrass growth. We returned one year after the initial planting to monitor the success rate of the transplants. During the year after transplanting, we carried out a concurrent study on crab distribution inside and outside eelgrass meadows to study crab usage of the habitat. One year after the initial transplant, two sites, one in Baker Bay and one in Young's Bay, had good survival or expansion rates with healthy eelgrass. Two sites had poor survival rates, and one site had a total loss of the transplanted eelgrass. For submerged aquatic vegetation (SAV) restoration

  2. Invasion risks posed by ornamental freshwater fish trade to southeastern Brazilian rivers

    Directory of Open Access Journals (Sweden)

    André Lincoln Barroso de Magalhães

    Full Text Available A model was developed to assess the risk of invasion of ornamental non-native fishes to six rivers in the state of Minas Gerais, southeastern Brazil, with focus on species popularity. Thirty-nine aquarium shops, in six cities, were visited monthly from January to December 2007. In each city, fish species were identified, and their biology and invasion history information was obtained from the literature. We calculated the annual frequency of occurrence and average number of specimens monthly available in stores. Quarterly water temperature and dissolved oxygen data from 1997 to 2007 were obtained for the Velhas, Muriaé, Uberabinha, Sapucaí-Mirim, Doce and Todos os Santos Rivers from public databases. The invasion risk of each species was assessed through a model comprising nine parameters grouped in four variables: (i Invasiveness (thermal and dissolved oxygen ranges, diet, parental care or fecundity, (ii History of invasions (establishment, (iii Propagule pressure (commercial success, comprising annual frequency of occurrence and number of specimens available monthly at stores, and (iv Invasibility (water temperature and dissolved oxygen in the target river compatible with the species ranges. Of the 345 ornamental fish species for sale, 332 are non-native to either Minas Gerais (n = 151 or Brazil (n = 194. Based on the proposed cutting values, in particular the compatibility between species and recipient thermal ranges, five ornamental non-native species (Cyprinus rubrofuscus, Carassius auratus, Xiphophorus hellerii, Poecilia reticulata, and P. latipinna can potentially invade the Velhas and Muriaé Rivers, four species (Cyprinus rubrofuscus, Carassius auratus, X. helleri, and P. reticulata the Uberabinha River, four species (Cyprinus rubrofuscus, Carassius auratus, X. maculatus, and P. reticulata the Sapucaí-Mirim River, three species (Carassius auratus, X. hellerii, and P. reticulata the Doce River, and three species (Cyprinus rubrofuscus

  3. Evaluation of HCMM satellite data for estuarine tidal circulation patterns and thermal inertia soil moisture measurements. [Delaware Bay, Cooper River, and the Potomac River estuaries; Luverne, Minnesota, soil moisture, and water temperature of Lake Anna, Virginia

    Science.gov (United States)

    Wiesnet, D. R.; Mcginnis, D. F., Jr. (Principal Investigator); Matson, M.; Pritchard, J. A.

    1981-01-01

    Digital thermal maps of the Cooper River (SC) and the Potomac River estuaries were prepared from heat capacity mapping radiometer (HCMR) tapes. Tidal phases were correctly interpreted and verified. Synoptic surface circulation patterns were charted by location thermal fronts and water mass boundaries within the estuaries. Thermal anomalies were detected adjacent of a conventional power plant on the Potomac. Under optimum conditions, estuaries as small as the Cooper River can be monitored for generalized thermal/tidal circulation patterns by the HCMM-type IR sensors. The HCMM thermal inertia approach to estimating soil moisture at the Luverne (MN) test site was found to be unsatisfactory as a NESS operational satellite technique because of cloud cover interference. Thermal-IR data show similar structure of the Baltimore and Washington heat islands when compared to NOAA AVHRR thermal-IR data. Thermal anomalies from the warm water discharge water of a nuclear power plant were mapped in Lake Anna, Virginia.

  4. Quantifying the effect of predators on endangered species using a bioenergetics approach : Caspian terns and juvenile salmonids in the Columbia River estuary

    NARCIS (Netherlands)

    Roby, DD; Lyons, DE; Craig, DP; Collis, K; Visser, GH

    2003-01-01

    We estimated the consumption of juvenile salmonids (Oncorhynchus spp.) and other forage fishes by Caspian terns (Sterna caspia) nesting on Rice Island in the Columbia River estuary in 1997 and 1998 using a bioenergetics modeling approach. The study was prompted by concern that Caspian tern predation

  5. Influence of filtration and glucose amendment on bacterial growth rate at different tidal conditions in the Minho Estuary River (NW Portugal)

    DEFF Research Database (Denmark)

    Anne, I.; Fidalgo, M. L.; Thosthrup, L.

    2006-01-01

    Bacterioplankton abundance, biomass and growth rates were studied in the Minho Estuary River (NW Portugal). The influence of tidal conditions, glucose amendment, and the filtration process on total bacterial abundance, total and faecal coliforms, as well as faecal streptococci, were evaluated...

  6. 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

    Digital Repository Service at National Institute of Oceanography (India)

    Samanta, S.; Dalai, T.K.; Pattanaik, J.K.; Rai, S.K.; Mazumdar, A.

    to the oceans, which accounts for ca. 0.2% of the global river water flux. The results of this study suggest that estuaries in regions affected by tropical monsoon can be important in terms of their production of significant amounts of DIC and its delivery...

  7. Polycyclic aromatic hydrocarbons in sediments from the Old Yellow River Estuary, China: occurrence, sources, characterization and correlation with the relocation history of the Yellow River.

    Science.gov (United States)

    Yuan, Zijiao; Liu, Guijian; Wang, Ruwei; Da, Chunnian

    2014-11-01

    The levels of 16 USEPA priority PAHs were determined in surface sediments and one dated sediment core from the abandoned Old Yellow River Estuary, China. Total PAH concentrations in the surface sediments ranged from 100.4 to 197.3 ng g(-1) dry weight and the total toxic equivalent quantity (TEQ(carc)) values of the carcinogenic PAHs were very low. An evaluation of PAH sources based on diagnostic ratios and principal component analysis suggested that PAHs in the surface sediments mainly derived from combustion sources. The total PAH concentrations altered significantly with year of deposition and showed quite different patterns of change compared with other studies: it is hypothesized that the principal cause of these changes is the relocation of the course of the Yellow River to the sea in 1976 and 1996. Copyright © 2014 Elsevier Inc. All rights reserved.

  8. Some aspects of the biology of the female blue crab Callinectes amnicola (De Rocheburne) from the Cross River estuary, Nigeria

    Institute of Scientific and Technical Information of China (English)

    Eyo Victor Oscar; Akpan Michael Mfon; Udoh Ifiok Solomon

    2015-01-01

    Objective: To investigate some important aspects of the biology of Callinectes amnicola (C. amnicola) such as fecundity, carapace length-weight relationship, condition factor and carapace length frequency distribution from the Cross River estuary, Nigeria. Methods: A total of one hundred and twenty ovigerous females of C. amnicola, freshly caught with basket traps, lift net trap, and gill net were collected from the catches of the artisanal fisheries in the study area between June 2012 and May 2013. Fecundity, carapace length-weight relationship, condition factor and carapace length frequency distribution were determined and analyzed following standard methods. Results: Fecundity (F) ranged between 73090 eggs for crab of carapace length 8.1 cm and total weight 34 g and 809450 eggs for crab of carapace length 16.1 cm and total weight 395 g with a mean of 311808.93±17693.94 eggs. There was a positive significant relationship between fecundity and carapace length, total weight and condition factor as follows: F=6839.7CL1.4403 (r2=0.2145, P<0.05), F=15302TW0.5798 (r2=0.4079, P<0.05), F=147255K0.2788 (r=0.2717, r2=0.0738, P<0.05). A significant linear relationship between carapace length and weight of C. amnicola is given by the equation: Log W=2.0447LogL – 0.1389 (r2=0.3357, P<0.05). The crab exhibited a negative allometric growth pattern (b=2.0447). Condition factor ranged between 21.48 to 104.95 with a mean value of 47.21±2.17. The carapace length frequency distribution showed a unimodal class size distribution. Conclusions: Findings of this study is crucial in assessing the population dynamics and development of management strategies of the the Blue crab, C. amnicola from the estuary such as mesh size regulation, fishing season and fishing ground regulation in the Cross River estuary. Also, findings of this study will be useful in evaluation of the aquaculture potential of the Blue crab C. amnicola, which is a valuable shell fish for the inhabitants estuary.

  9. Some aspects of the biology of the female blue crab Callinectes amnicola (De Rocheburne from the Cross River estuary, Nigeria

    Directory of Open Access Journals (Sweden)

    Eyo Victor Oscar

    2015-04-01

    Full Text Available Objective: To investigate some important aspects of the biology of Callinectes amnicola (C. amnicola such as fecundity, carapace length-weight relationship, condition factor and carapace length frequency distribution from the Cross River estuary, Nigeria. Methods: A total of one hundred and twenty ovigerous females of C. amnicola, freshly caught with basket traps, lift net trap, and gill net were collected from the catches of the artisanal fisheries in the study area between June 2012 and May 2013. Fecundity, carapace length-weight relationship, condition factor and carapace length frequency distribution were determined and analyzed following standard methods. Results: Fecundity (F ranged between 73090 eggs for crab of carapace length 8.1 cm and total weight 34 g and 809450 eggs for crab of carapace length 16.1 cm and total weight 395 g with a mean of 311808.93±17 693.94 eggs. There was a positive significant relationship between fecundity and carapace length, total weight and condition factor as follows: F=6839.7CL1.4403 (r 2 =0.2145, P<0.05, F=15302TW0.5798 (r 2 =0.4079, P<0.05, F=147255K0.2788 (r=0.2717, r 2 =0.0738, P<0.05. A significant linear relationship between carapace length and weight of C. amnicola is given by the equation: Log W=2.0447LogL – 0.1389 (r 2 =0.3357, P<0.05. The crab exhibited a negative allometric growth pattern (b=2.0447. Condition factor ranged between 21.48 to 104.95 with a mean value of 47.21±2.17. The carapace length frequency distribution showed a unimodal class size distribution. Conclusions: Findings of this study is crucial in assessing the population dynamics and development of management strategies of the the Blue crab, C. amnicola from the estuary such as mesh size regulation, fishing season and fishing ground regulation in the Cross River estuary. Also, findings of this study will be useful in evaluation of the aquaculture potential of the Blue crab C. amnicola, which is a valuable shell fish for the

  10. Streamflow gains and losses in the Colorado River in northwestern Burnet and southeastern San Saba Counties, Texas

    Science.gov (United States)

    Braun, Christopher L.; Grzyb, Scott D.

    2015-08-12

    In October 2012, the U.S. Geological Survey (USGS), in cooperation with the Central Texas Groundwater Conservation District, began an assessment to better understand if and where groundwater from the Ellenburger-San Saba aquifer is discharging to the Colorado River, and if and where Colorado River streamflow is recharging the Ellenburger-San Saba aquifer in the study area. Discharge measurements were made to determine if different reaches of the Colorado River in northwestern Burnet and southeastern San Saba Counties are gaining or losing streamflow, the locations and quantities of gains and losses, and whether the gains and losses can be attributed to interaction between the river and the Ellenbuger-San Saba aquifer. To assess streamflow gains and losses, two sets of synoptic gain-loss discharge measurements representing different streamflow conditions were completed. In the first gain-loss streamflow survey during December 3–6, 2012 (hereinafter the fall 2012 gain-loss survey), discharge measurements were made at low-flow conditions ranging from about 30 to 60 cubic feet per second (ft3/s) at seven locations along the Colorado River. In the second gain-loss streamflow survey during May 31–June 1, 2014 (hereinafter the spring 2014 gain-loss survey), discharge measurements were made at high-flow conditions ranging from about 660 to 900 ft3/s at 12 locations along the Colorado River.

  11. Continuous tidal streamflow, water level, and specific conductance data for Union Creek and the Little Back, Middle, and Front Rivers, Savannah River Estuary, November 2008 to March 2009

    Science.gov (United States)

    Lanier, Timothy H.; Conrads, Paul A.

    2010-01-01

    In the Water Resource Development Act of 1999, the U.S. Congress authorized the deepening of the Savannah Harbor. Additional studies were then identified by the Georgia Ports Authority and other local and regional stakeholders to determine and fully describe the potential environmental effects of deepening the channel. One need that was identified was the validation of a three-dimensional hydrodynamic model developed to evaluate mitigation scenarios for a potential harbor deepening and the effects on the Savannah River estuary. The streamflow in the estuary is very complex due to reversing tidal flows, interconnections of streams and tidal creeks, and the daily flooding and draining of the marshes. The model was calibrated using very limited streamflow data and no continuous streamflow measurements. To better characterize the streamflow dynamics and mass transport of the estuary, two index-velocity sites were instrumented with continuous acoustic velocity, water level, and specific conductance sensors on the Little Back and Middle Rivers for the 5-month period of November 2008 through March 2009. During the same period, a third acoustic velocity meter was installed on the Front River just downstream from U.S. Geological Survey streamgaging station 02198920 (Savannah River at GA 25, at Port Wentworth, Georgia) where water level and specific conductance data were being collected. A fourth index-velocity site was instrumented with continuous acoustic velocity, water level, and specific conductance sensors on Union Creek for a 2-month period starting in November 2008. In addition to monitoring the tidal cycles, streamflow measurements were made at the four index-velocity sites to develop ratings to compute continuous discharge for each site. The maximum flood (incoming) and ebb (outgoing) tides measured on Little Back River were –4,570 and 7,990 cubic feet per second, respectively. On Middle River, the maximum flood and ebb tides measured were –9,630 and 13

  12. Estuarine Landcover Along the Lower Columbia River Estuary Determined from Compact Ariborne Spectrographic Imager (CASI) Imagery, Technical Report 2003.

    Energy Technology Data Exchange (ETDEWEB)

    Garono, Ralph; Robinson, Rob

    2003-10-01

    Developing an understanding of the distribution and changes in estuarine and riparian habitats is critical to the management of biological resources in the lower Columbia River. In a recently completed comprehensive ecosystem protection and enhancement plan for the lower Columbia River Estuary (CRE), Jerrick (1999) identified habitat loss and modification as one of the key threats to the integrity of the CRE ecosystem. This management plan called for an inventory of habitats as key first step in the CRE long-term restoration effort. While previous studies have produced useful data sets depicting habitat cover types along portions of the lower CRE (Thomas, 1980; Thomas, 1983; Graves et al., 1995; NOAA, 1997; Allen, 1999), no single study has produced a description of the habitats for the entire CRE. Moreover, the previous studies differed in data sources and methodologies making it difficult to merge data or to make temporal comparisons. Therefore, the Lower Columbia River Estuary Partnership (Estuary Partnership) initiated a habitat cover mapping project in 2000. The goal of this project was to produce a data set depicting the current habitat cover types along the lower Columbia River, from its mouth to the Bonneville Dam, a distance of {approx}230-km (Fig. 1) using both established and emerging remote sensing techniques. For this project, we acquired two types of imagery, Landsat 7 ETM+ and Compact Airborne Spectrographic Imager (CASI). Landsat and CASI imagery differ in spatial and spectral resolution: the Landsat 7 ETM+ sensor collects reflectance data in seven spectral bands with a spatial resolution of 30-m and the CASI sensor collects reflectance data in 19 bands (in our study) with a spatial resolution of 1.5-m. We classified both sets of imagery and produced a spatially linked, hierarchical habitat data set for the entire CRE and its floodplain. Landsat 7 ETM+ classification results are presented in a separate report (Garono et al., 2003). This report

  13. Eelgrass Enhancement and Restoration in the Lower Columbia River Estuary, Period of Performance: Feb 2008-Sep 2009.

    Energy Technology Data Exchange (ETDEWEB)

    Judd, C.; Thom, R; Borde, A. [Pacific Northwest National Laboratory

    2009-09-08

    The purpose of this study was to evaluate the ability to enhance distribution of eelgrass (Zostera marina) in the Columbia River Estuary to serve as refuge and feeding habitat for juvenile salmon, Dungeness crab, and other fish and wildlife. We strongly suspected that limited eelgrass seed dispersal has resulted in the present distribution of eelgrass meadows, and that there are other suitable places for eelgrass to survive and form functional meadows. Funded as part of the Bonneville Power Administration's call for Innovative Projects, we initiated a multistage study in 2008 that combined modeling, remote sensing, and field experimentation to: (1) Spatially predict habitat quality for eelgrass; (2) Conduct experimental plantings; and (3) Evaluate restoration potential. Baseline in-situ measurements and remote satellite observations were acquired for locations in the Lower Columbia River Estuary (LCRE) to determine ambient habitat conditions. These were used to create a habitat site-selection model, using data on salinity, temperature, current velocity, light availability, wave energy, and desiccation to predict the suitability of nearshore areas for eelgrass. Based on this model and observations in the field, five sites that contained no eelgrass but appeared to have suitable environmental conditions were transplanted with eelgrass in June 2008 to test the appropriateness of these sites for eelgrass growth. We returned one year after the initial planting to monitor the success rate of the transplants. During the year after transplanting, we carried out a concurrent study on crab distribution inside and outside eelgrass meadows to study crab usage of the habitat. One year after the initial transplant, two sites, one in Baker Bay and one in Young's Bay, had good survival or expansion rates with healthy eelgrass. Two sites had poor survival rates, and one site had a total loss of the transplanted eelgrass. For submerged aquatic vegetation (SAV) restoration

  14. [Effects of macro-jellyfish abundance dynamics on fishery resource structure in the Yangtze River estuary and its adjacent waters].

    Science.gov (United States)

    Shan, Xiu-Juan; Zhuang, Zhi-Meng; Jin, Xian-Shi; Dai, Fang-Qun

    2011-12-01

    Based on the bottom trawl survey data in May 2007 and May and June 2008, this paper analyzed the effects of the abundance dynamics of macro-jellyfish on the species composition, distribution, and abundance of fishery resource in the Yangtze River estuary and its adjacent waters. From May 2007 to June 2008, the average catch per haul and the top catch per haul of macro-jellyfish increased, up to 222.2 kg x h(-1) and 1800 kg x h(-1) in June 2008, respectively. The macro-jellyfish were mainly distributed in the areas around 50 m isobath, and not beyond 100 m isobath where was the joint front of the coastal waters of East China Sea, Yangtze River runoff, and Taiwan Warm Current. The main distribution area of macro-jellyfish in June migrated northward, as compared with that in May, and the highest catches of macro-jellyfish in May 2007 and May 2008 were found in the same sampling station (122.5 degrees E, 28.5 degrees N). In the sampling stations with higher abundance of macro-jellyfish, the fishery abundance was low, and the fishery species also changed greatly, mainly composed by small-sized species (Trachurus japonicus, Harpadon nehereus, and Acropoma japonicum) and pelagic species (Psenopsis anomala, Octopus variabilis) and Trichiurus japonicus, and P. anomala accounted for 23.7% of the total catch in June 2008. Larimichthys polyactis also occupied higher proportion of the total catch in sampling stations with higher macro-jellyfish abundance, but the demersal species Lophius litulon was not found, and a few crustaceans were collected. This study showed that macro-jellyfish had definite negative effects on the fishery community structure and abundance in the Yangtze River estuary fishery ecosystem, and further, changed the energy flow patterns of the ecosystem through cascading trophic interactions. Therefore, macro-jellyfish was strongly suggested to be an independent ecological group when the corresponding fishery management measures were considered.

  15. Protection and Utilization of Ecotourism Resources at the Estuary of the Yellow River%黄河三角洲入海口生态旅游资源的保护利用

    Institute of Scientific and Technical Information of China (English)

    翁森红

    2005-01-01

    There are plentiful ecotourism resources at the estuary of the Yellow River. The characteristic of the resources are vast, wild, rare, peculiar and fresh. Some natural resources, ecotourism resources on the wetland nature reserve of the estuary, and the special landscape ecology resources are introduced in this paper. The author also suggests that the sustainable development of the travel industry at the estuary should be based on the protection and reasonable utilization of the ecosystem.

  16. Effect of river discharge and geometry on tides and net water transport in an estuarine network, an idealised model applied to the Yangtze Estuary

    Science.gov (United States)

    de Swart, Huib E.; Alebregtse, Niels C.

    2015-04-01

    Many estuaries in the world show a complex pattern of interconnected branches. The water motion in these estuarine networks is dominated by tides and by net water transport, the latter being primarily forced by river discharge and by nonlinear tidal rectification processes. The behaviour of tides (sea surface height and currents) and the distribution of net water transport over the branches is an important topic of research, e.g. for flushing of pollutants, salinity intrusion and sediment transport. Field observations, e.g. in the Yangtze Estuary, show that tides and distribution of net water transport over the branches are highly sensitive to river discharge (wet and dry season) and to changes in geometry, e.g. due to navigational works. To understand such sensivities, this contribution presents a semi-analytical model that yields explicit solutions for tides and net water transport for arbitrary tidal network configurations. The model accounts for tide-river interactions, which in particular affect friction, and for tidal rectification processes. The model is subsequently applied to the Yangtze Estuary. It will be shown that tide-river interactions are crucial to understand the observed differences in tidal propagation between the wet and dry season. Furthermore, the relative increase of the net water transport driven by tidal rectification with respect to that driven by river discharge explains the observed differences in distribution of water transport over the branches between wet and dry season in this estuary. Finally, it will be shown that the construction of navigational works resulted in an increase of tidal currents, a decrease of net water transport and an increase in ebb-dominance in the North Passage of the Yangtze Estuary, consistent with observations.

  17. A modeling study of the impacts of Mississippi River diversion and sea-level rise on water quality of a deltaic estuary

    Science.gov (United States)

    Wang, Hongqing; Chen, Qin; Hu, Kelin; LaPeyre, Megan K.

    2017-01-01

    Freshwater and sediment management in estuaries affects water quality, particularly in deltaic estuaries. Furthermore, climate change-induced sea-level rise (SLR) and land subsidence also affect estuarine water quality by changing salinity, circulation, stratification, sedimentation, erosion, residence time, and other physical and ecological processes. However, little is known about how the magnitudes and spatial and temporal patterns in estuarine water quality variables will change in response to freshwater and sediment management in the context of future SLR. In this study, we applied the Delft3D model that couples hydrodynamics and water quality processes to examine the spatial and temporal variations of salinity, total suspended solids, and chlorophyll-α concentration in response to small (142 m3 s−1) and large (7080 m3 s−1) Mississippi River (MR) diversions under low (0.38 m) and high (1.44 m) relative SLR (RSLR = eustatic SLR + subsidence) scenarios in the Breton Sound Estuary, Louisiana, USA. The hydrodynamics and water quality model were calibrated and validated via field observations at multiple stations across the estuary. Model results indicate that the large MR diversion would significantly affect the magnitude and spatial and temporal patterns of the studied water quality variables across the entire estuary, whereas the small diversion tends to influence water quality only in small areas near the diversion. RSLR would also play a significant role on the spatial heterogeneity in estuary water quality by acting as an opposite force to river diversions; however, RSLR plays a greater role than the small-scale diversion on the magnitude and spatial pattern of the water quality parameters in this deltaic estuary.

  18. Surface-sediment and hermit-crab contamination by butyltins in southeastern Atlantic estuaries after ban of TBT-based antifouling paints.

    Science.gov (United States)

    Sant'Anna, B S; Santos, D M; Marchi, M R R; Zara, F J; Turra, A

    2014-05-01

    Butyltin (BT) contamination was evaluated in hermit crabs from 25 estuaries and in sediments from 13 of these estuaries along about 2,000 km of the Brazilian coast. BT contamination in hermit crabs ranged from 2.22 to 1,746 ng Sn g(-1) of DBT and 1.32 to 318 ng Sn g(-1) of TBT. In sediment samples, the concentration also varied widely, from 25 to 1,304 ng Sn g(-1) of MBT, from 7 to 158 ng Sn g(-1) of DBT, and from 8 to 565 ng Sn g(-1) of TBT. BTs are still being found in surface sediments and biota of the estuaries after the international and Brazilian bans, showing heterogeneous distribution among and within estuaries. Although hermit crabs were previously tested as an indicator of recent BT contamination, the results indicate the presence of contamination, probably from resuspension of BTs from deeper water of the estuary.

  19. Spatial distribution and temporal trends of soft-bottom marine benthic alien species collected during the period 1989-2008 in the Nervión estuary (southeastern Bay of Biscay)

    Science.gov (United States)

    Zorita, Izaskun; Solaun, Oihana; Borja, Angel; Franco, Javier; Muxika, Iñigo; Pascual, Marta

    2013-10-01

    As the introduction of alien species represents one of the most important causes of biodiversity loss, it is crucial to study the distribution of alien species in order to control or eradicate their introduction and spread. Thus, the present study aimed to analyse the spatial distribution and temporal trends of soft-bottom marine benthic alien species collected during 20 years in the Nervión estuary, southeastern Bay of Biscay. Results indicated that, from a total of 6688 species records, 117 corresponded to alien species. Likewise, from a total of 742 different species identified, 23 species were classified as alien species. The two most frequently recorded alien species, Pseudopolydora paucibranchiata and Monocorophium acherusicum, appeared mainly at the intermediate part of the estuary that suffered historically an intense pollution. The presence and abundance of soft-bottom alien species became more evident since the mid-nineties, when the widening of the Bilbao Harbour occurred, together with a water quality improvement and the industry decline. Finally, although the identified alien species are considered as not invasive, the spread of alien species in the estuary might be considered as a threat.

  20. Spatiotemporal Distribution of Metals along a Salinity Gradient in a River Estuary of the Northern Gulf of Mexico

    Science.gov (United States)

    He, S.; Xu, Y. J.

    2015-12-01

    Saltwater intrusion has become a significant problem for many coastal rivers due to global climate change and the continuous sea level rise. The flocculation of dissolved metals during estuarine mixing plays a critical role in self-purification of metals. A number of studies have investigated pH and salinity effects on metal mobility. Many of these studies were conducted in a laboratory setting. The reported field studies considered only few metals and their dynamics under marginal pH / salinity variation, typically over a short period of time. Since the spring of 2013, we have been conducting a study on spatiotemporal distribution of metals along a 90-km reach of the Calcasieu River estuary in the northern Gulf of Mexico. Monthly field trips were made to conduct in-situ measurements and collect water samples at six sites along the river. In addition, sediment samples from the riverbed surface were collected at the same sites four times to assess metal accumulation. Field measurements included water temperature, pH, salinity, and specific conductivity; Water samples were analyzed for concentration of a range of metals including Al, Ba, B, Cd, Ca, Cr, Cu, Fe, Pb, Li, Mg, Mn, Ni, P, K, Si, Ag, Na, Sr, Ti, V, and Zn. The estuarine river reach showed a wide range of salinity and pH (salinity: 0.04 - 21.78 ppt; pH: 6.2-8.1), strongly affected by river hydrology and tidal mixing. Concentration and spatial distribution of the metals in river water show response to flow regimes from the low (400 cfs) to the intermediate (400-2600 cfs) and high flows. This paper presents the dynamics of the metals under varying flow, pH and salinity gradients over the seasons and discusses a potential "intrusion" of metal accumulation in riverbed upstream as sea level rise persists.

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

    Science.gov (United States)

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

    2013-01-01

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

  2. Responses of estuarine salinity and transport processes to sea level rise in the Zhujiang (Pearl River) Estuary

    Institute of Scientific and Technical Information of China (English)

    CHEN Yuxiang; ZUO Juncheng; ZOU Huazhi; ZHANG Min; ZHANG Kairong

    2016-01-01

    Understanding the changes of hydrodynamics in estuaries with respect to magnitude of sea level rise is important to understand the changes of transport process. Based on prediction of sea level rise over the 21st century, the Zhujiang (Pearl River) Estuary was chosen as a prototype to study the responses of the estuary to potential sea level rise. The numerical model results show that the average salt content, saltwater intrusion distance, and stratification will increase as the sea level rises. The changes of these parameters have obvious seasonal variations. The salt content in the Lingdingyang shows more increase in April and October (the transition periods). The saltwater intrusion distance has larger increase during the low-flow periods than during the high-flow periods in the Lingdingyang. The result is just the opposite in Modaomen. The stratification and its increase are larger during the low-flow periods than during the high-flow periods in Lingdingyang. The response results of transport processes to sea level rise demonstrate that: (1) The time of vertical transport has pronounced increase. The increased tidal range and currents would reinforce the vertical mixing, but the increased stratification would weaken the vertical exchange. The impact of stratification changes overwhelms the impact of tidal changes. It would be more difficult for the surface water to reach the bottom. (2) The lengthways estuarine circulation would be strengthened. Both the offshore surface residual current and inshore bottom residual current will be enhanced. The whole meridional resident flow along the transect of the Lingdingyang would be weakened. These phenomena are caused by the decrease of water surface slope (WWS) and the change of static pressure with the increase of water depth under sea level rise.

  3. Distribution and community structure of fish in Obitsu-gawa River Estuary of inner Tokyo Bay, central Japan

    Directory of Open Access Journals (Sweden)

    Joeppette J. Hermosilla

    2012-09-01

    Full Text Available The distribution and community structure of fish in Obitsu-gawa River Estuary of inner TokyoBay, central Japan was studied from May to December 2005 and March to April 2006. A total of 19,006individuals, represented by 25 species and some unidentified species under family Clupeidae, Cyprinidae,Gobiidae, Hemiramphidae, Mugilidae, Platycephidae, Pleuronectidae and Triglidae were collected. FamilyGobiidae had the most number of taxa with 13 genera and 10 species. Greatest fish abundancehappened in August and secondarily in April and May. Species richness was evident in the warmermonths particularly in May (17 taxa, August (21 taxa, September (15 taxa and October (17 taxa.Marine teleosts significantly contributed to the species richness and abundance of fish, whichcorresponded to 52.9% (10,046 individuals of the total catch while the estuarine fishes were the secondmost abundant group with 33.5% (6,372 individuals of the total catch. Species dominance was acoherent feature of this community. The proportional contribution of marine teleosts to the fishcommunity decreased with increase distance upstream while that of estuarine fishes increased withincrease distance upstream. The developmental stages of gobies range from larvae to adult but juvenilesconstitute 77.06% of the total sample. The distribution of developmental stage of estuarine gobies wasinfluenced to a greater extent by variation in monthly water temperature and station or the interaction ofboth. Adult estuarine gobies had the tendency to aggregate in the middle estuary reflecting their hightolerance to a wide range of water salinity inherent in this station but avoided the lower estuary mostlikely due to the predominance of high salinity waters.

  4. Use of Reflectance Ratios as a Proxy for Coastal Water Constituent Monitoring in the Pearl River Estuary

    Directory of Open Access Journals (Sweden)

    Hong-Li Li

    2009-01-01

    Full Text Available 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 TSSconcentrations 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‰.

  5. Using mercury isotopes to understand the bioaccumulation of Hg in the subtropical Pearl River Estuary, South China.

    Science.gov (United States)

    Yin, Runsheng; Feng, Xinbin; Zhang, Junjun; Pan, Ke; Wang, Wenxiong; Li, Xiangdong

    2016-03-01

    Coastal and estuarine regions are important areas of mercury pollution. Therefore, it is important to properly characterize the sources and bioaccumulation processes of mercury in these regions. Here, we present mercury stable isotopic compositions in 18 species of wild marine fish collected from the Pearl River Estuary (PRE), south China. Our results showed variations in mass-independent fractionation (Δ(199)Hg: +0.05 ± 0.10‰ to +0.59 ± 0.30‰) with a Δ(199)Hg/Δ(201)Hg of ∼1.26, suggesting that aqueous MeHg underwent photo-degradation prior to incorporation into the food chain. For the results, we discovered small but significant differences of Δ(199)Hg values among herbivorous, demersal, and carnivorous fish, indicating that different feeding guilds of fish may have incorporated MeHg with various degrees of photo-demethylation. The consistent mercury isotope compositions between fish feeding habitat and mercury sources in the estuary provide potentially important findings on the transformation and bioaccumulation of this toxic metal in subtropical coastal environments.

  6. Use of Satellite Images to map Flood Extension around the city of Saint Louis in the Senegal River Estuary

    Directory of Open Access Journals (Sweden)

    Aliou Dia

    2006-04-01

    Full Text Available The traditional method of landsat satellite data combination and the gathering of important information made it possible to produce a Geographical Information System to monitor floods in the lower estuary of the Senegal River valley (Sandholt,I., Fog, B. & Fensholt, R., 2001. This technical approach is a powerful tool for combining important information for a better comprehension of the floods and the characterization of surface qualities on the estuary. By way of a multi-temporal approach, the study team established the qualitative and quantitative impact of floods on the various geographical objects, a detailed cartography of the land use and the surfaces flooded in 1998 and 1999. The study undertaken in Saint Louis made it possible to consider surfaces flooded in 1999, and to understand the extent of these floods compared to those of 1998. The constitution of a tool of decision-making aid makes it possible to have information relating to the extent of the flood, the scope of flooded surfaces and to detect the more exposed zones in order to establish a hierarchical map according to the percentage of exposure to the risk of the geographical objects affected by the floods (populations, road infrastructures and tracks, medical and social infrastructures and perimeters of cultures (agriculture.

  7. Foraging strategies of Southern sea lion females in the La Plata River Estuary (Argentina-Uruguay)

    Science.gov (United States)

    Rodríguez, Diego H.; Dassis, Mariela; Ponce de León, Alberto; Barreiro, César; Farenga, Marcelo; Bastida, Ricardo O.; Davis, Randall W.

    2013-04-01

    The stocks of Southern sea lions (Otaria flavescens, SSL) and South American fur seals (SAFS) that breed on coastal islands of Uruguay constitute the most important focal concentration of pinnipeds in South America, with a significant increase in SAFS and a steady decrease of SSL over the past decades. Because females are a key element of population dynamics and no information exists on the post-breeding pup rearing period, we studied the foraging patterns of SSL females in the La Plata River Estuary (LPRE) during mid and late lactation (late austral autumn and winter), analyzing the foraging performance, geographic coverage and ontogenetic differences in foraging strategies for a period of 1-5 months. At-sea movements of 22 SSL females (6 subadults and 16 adults) from Isla de Lobos (IL, 35°01'28"S-54°52'59"W, Uruguay) were monitored using satellite transmitters (SPOT4, SPOT5 and STDR-S16, Wildlife Computers) in 2007 and 2010. An algorithm [McConnell, B.J., Chambers, C., Fedak, M.A., 1992. Foraging ecology of southern elephant seals in relation to the bathymetry and productivity of the Southern Ocean. Antarct. Sci. 4, 393-398.] with a maximum transit speed of 3 m s-1 was applied to the Argos information, resulting in a total of 2522 filtered locations. A daily mean of 3.5±1.74 filtered locations per animal was received. One hundred and eighty three foraging trips (FT) were recorded with no significant differences (p<0.05) between subadults and adults in the duration of FT (6.1±3.15 day), distance traveled per FT (237.2±105.25 km), mean distance from IL (57.2±25.90 km), maximum straight line (Spider) distance (100.2±41.40 km) and transit speed (1.1±1.04 m s-1). SSL showed directional fidelity to foraging sites, indicated by high mean vector (r) values (0.74±0.14) calculated from FT mean bearings. Kernel ranges for 50% and 95% of all FT locations were 5420 km2 and 36,222 km2, respectively, and the extension of the foraging areas appeared to be influenced by

  8. Analysis of stratification patterns in river-influenced mesotidal and macrotidal estuaries using 3D hydrodynamic modelling and K-means clustering

    Science.gov (United States)

    Bárcena, Javier F.; García-Alba, Javier; García, Andrés; Álvarez, César

    2016-11-01

    A methodology to determine the spatial and temporal evolution of stratification in estuaries driven by astronomical tides and river discharges was developed and is presented here. Using a 3D hydrodynamic model, the variation of estuarine currents, water levels and densities was investigated under different realistic forcing conditions. These conditions were classified from a long-term period (>30 years) of river flows and tidal water levels by a K-means clustering approach suggested by Bárcena et al. (2015). The methodology allows computing the location of mixed, partially mixed/stratified and stratified areas in tidal river estuaries along a continuum by means of Richardson's Layer number and the frequency of every model scenario. In order to illustrate the power of the method, it was applied to a case study, the Suances Estuary. In the application case, the Suances Estuary was vertically mixed at its innermost part due to riverine influence. At the outer part, it was also vertically mixed due to the turbulence caused by tidal action. At the intermediate section, it was partially mixed in the main channel or stratified in intertidal areas due to the combined action of forcing, depth gradients between the main channel and intertidal areas, and salinity variations in the water column.

  9. Evaluation of Life History Diversity, Habitat Connectivity, and Survival Benefits Associated with Habitat Restoration Actions in the Lower Columbia River and Estuary, Annual Report 2009

    Energy Technology Data Exchange (ETDEWEB)

    Diefenderfer, Heida L.; Johnson, Gary E.; Sather, Nichole K.; Skalski, John R.; Dawley, Earl M.; Coleman, Andre M.

    2010-08-01

    This report describes the 2009 research conducted under the U.S. Army Corps of Engineers (USACE or Corps) project EST-09-P-01, titled “Evaluation of Life History Diversity, Habitat Connectivity, and Survival Benefits Associated with Habitat Restoration Actions in the Lower Columbia River and Estuary.” The research was conducted by the Pacific Northwest National Laboratory, Marine Science Laboratory and Hydrology Group, in partnership with the University of Washington, School of Aquatic and Fishery Sciences, Columbia Basin Research, and Earl Dawley (NOAA Fisheries, retired). This Columbia River Fish Mitigation Program project, referred to as “Salmonid Benefits,” was started in FY 2009 to evaluate the state-of-the science regarding the ability to quantify the benefits to listed salmonids1 of habitat restoration actions in the lower Columbia River and estuary.

  10. Spatial-temporal variation and moon effects on estuarine ichthyofauna: evidence for the Joanes River estuary – Bahia

    Directory of Open Access Journals (Sweden)

    José Amorim Reis-Filho

    2010-06-01

    Full Text Available Abundance, biomass, length, richness, diversity and equitability data were obtained to investigate the effect of lunar cycle and spatial-temporal variation on the ichthyofauna of the Joanes River estuary. 1,497 fish were captured, weighing 7,760g and belonging to 48 species of 22 families. The analysis of the community indicated no significant differences regarding the effects of the moon, although the waning moon was responsible for higher captures. The composition and structure of the ichthyofauna varied with the sediment type and mangrove vegetation, where more individuals and more species preferred the muddy sediment in areas with preserved marginal vegetation. Groupings based on the abundance data did not follow the temporal variations of a long period of time, but fish assemblages with similar niches in relation to the habitat use preferred certain areas according to the sediment type.

  11. Bioaccumulation of heavy metals in two matrices of the Bonny/New Calabar River Estuary in Niger Delta, Nigeria

    Science.gov (United States)

    Onojake, M. C.; Sikoki, F. D.; Babatunde, B. B.; Akpiri, R. U.; Akpuloma, D.; Omokheyeke, O.

    2015-06-01

    The concentrations of Ca, Mg, K, Zn, Pb, Cd, Co, Cr, Cu, Fe, Ni and Na were determined in the sediment and biota of the Bonny/New Calabar River Estuary in Niger Delta, Nigeria using atomic absorption spectrophotometer A-100. The concentration of the respective metals varied between 2011 and 2012. The range of mean values are presented in mg/kg along with variations at a statistically significant level ( PBioaccumulation factor (BF) indicated a more potent source of metals from sediment than biota, accumulating Zn, Fe and Ni in magnitudes 10, 6 and 5 times more, respectively. The study shows elevated levels of heavy metals in sediment and bioaccumulation in biota. Regular monitoring and comparison of results with World Health Organization maximum permissible limits should be carried out, in order not to allow the metal concentration to reach alarming levels.

  12. Environmental risk assessments and spatial variations of polycyclic aromatic hydrocarbons in surface sediments in Yangtze River Estuary, China.

    Science.gov (United States)

    Yu, Wenwen; Liu, Ruimin; Xu, Fei; Shen, Zhenyao

    2015-11-15

    In this study, based on sampling data from 30 sites in August 2010, the environmental risks associated with 16 priority PAHs were estimated in surface sediments from the Yangtze River Estuary (YRE). The results indicated that the toxic equivalent quantities of the benzo[a]pyrene (TEQBap) from 30 sites were in the range of 1.93-75.88ngg(-1), and the low-molecular-weight PAHs were the dominated species with higher potential toxicity. The results of the Incremental Lifetime Cancer Risk (ILCR) model indicated that the ILCR values of dermal contact were higher than 10(-6) in the northeast region, suggesting that there were significant potential carcinogenic health risks for fishermen exposure to sedimentary PAHs via dermal contact in these areas. RQ values of PAHs indicated the various distributions of ecological risk levels in the study area. These variations might be caused by the natural and anthropogenic inputs and currents in the YRE.

  13. Modeling ecosystem processes with variable freshwater inflow to the Caloosahatchee River Estuary, southwest Florida. I. Model development

    Science.gov (United States)

    Buzzelli, Christopher; Doering, Peter H.; Wan, Yongshan; Sun, Detong; Fugate, David

    2014-12-01

    Variations in freshwater inflow have ecological consequences for estuaries ranging among eutrophication, flushing and transport, and high and low salinity impacts on biota. Predicting the potential effects of the magnitude and composition of inflow on estuaries over a range of spatial and temporal scales requires reliable mathematical models. The goal of this study was to develop and test a model of ecosystem processes with variable freshwater inflow to the sub-tropical Caloosahatchee River Estuary (CRE) in southwest Florida from 2002 to 2009. The modeling framework combined empirically derived inputs of freshwater and materials from the watershed, daily predictions of salinity, a box model for physical transport, and simulation models of biogeochemical and seagrass dynamics. The CRE was split into 3 segments to estimate advective and dispersive transport of water column constituents. Each segment contained a sub-model to simulate changes in the concentrations of organic nitrogen and phosphorus (ON and OP), ammonium (NH4+), nitrate-nitrite (NOx-), ortho-phosphate (PO4-3), phytoplankton chlorophyll a (CHL), and sediment microalgae (SM). The seaward segment also had sub-models for seagrasses (Halodule wrightii and Thalassia testudinum). The model provided realistic predictions of ON in the upper estuary during wet conditions since organic nitrogen is associated with freshwater inflow and low salinity. Although simulated CHL concentrations were variable, the model proved to be a reliable predictor in time and space. While predicted NOx- concentrations were proportional to freshwater inflow, NH4+ was less predictable due to the complexity of internal cycling during times of reduced freshwater inflow. Overall, the model provided a representation of seagrass biomass changes despite the absence of epiphytes, nutrient effects, or sophisticated translocation in the formulation. The model is being used to investigate the relative importance of colored dissolved organic

  14. Sedimentary BSi and TOC quantifies the degradation of the Changjiang Estuary, China, from river basin alteration and warming SST

    Science.gov (United States)

    Li, Maotian; Wang, Hong; Li, Yimiao; Ai, Wei; Hou, Lijun; Chen, Zhongyuan

    2016-12-01

    Environmental degradation in the Changjiang Estuary has recently become a global topic, given its proximity to Shanghai with a population >23 million. Intensification of human activities affecting the river basin is responsible for this degradation. Dam construction has cut off ca. 2/3 of the sediment flux to the sea, ca. 60% of the dissolved silicate load (DSi) has been retained in the reservoirs, while total phosphorous (TP) and total nitrogen (TN) transport to the sea are many times more than they were a few decades ago. Under such circumstances, details of the estuarine degradation remain poorly understood. This study uses sedimentary biological silicate (BSi) and total organic carbon (TOC) as environmental proxies to reveal the process-response of such degradation since the 1950s. Our results demonstrate the spatial differences of such degradation. The inner zone of the estuary used to be highly turbid, but presently has increasing diatom (BSi) and primary production (TOC), due to lower suspended sediment concentration (SSC) in relation to dam construction. In contrast, increasing riverine dissolved inorganic nitrate (DIN) and dissolved inorganic phosphorous (DIP) input (up to 2-5 times) and decreasing DSi provide a unique setting, with an excess in N and P, which catalyzes non-diatom algae in the less-turbid middle zone of the estuary. These are reflected by decreasing BSi and BSi/TOC since the 1950s, together with an increase of TOC of 20-40%. In the outer zone of the estuary, increasing DIN, DIP, and sea surface temperatures (SSTs), have resulted in the increase of diatom biomass by 15-20% and the growth of primary production by 30-60% since the 1950s. But the drastic decrease in DSi, Si/N, and Si/P depresses the ability of diatoms to develop, resulting in a reduction of 5-10% diatom proportion (BSi/TOC) since the 1930s. This study improves the understanding of the changing estuarine ecosystem in response to global change.

  15. Anthropogenic effects on bacterial diversity and function along a river-to-estuary gradient in Northwest Greece revealed by metagenomics.

    Science.gov (United States)

    Meziti, Alexandra; Tsementzi, Despina; Ar Kormas, Konstantinos; Karayanni, Hera; Konstantinidis, Konstantinos T

    2016-12-01

    Studies assessing the effects of anthropogenic inputs on the taxonomic and functional diversity of bacterioplankton communities in lotic ecosystems are limited. Here, we applied 16S rRNA gene amplicon and whole-genome shotgun sequencing to examine the microbial diversity in samples from the Kalamas River (Northwest Greece), a mid-size river that runs through agricultural and NATURA-protected areas, but also receives urban sewage from a large city through a manmade ditch. Samples from three different locations between the exit of the ditch and the estuary, during three different months showed that temporal differences of taxonomic and functional diversity were more pronounced than spatial ones, and water flow months were dominated by sewage inputs and soil-related organisms. Notably, microbial human gut signals were detectable over background freshwater and soil/runoff related signals, even at tens of kilometers downstream the city. These findings revealed the significance of allochthonous inputs on the composition and dynamics of river bacterial communities, and highlighted the potential of metagenomics for source tracking purposes. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

  16. Confirmatory chemical analyses and solid phase bioassays on sediment from the Columbia River Estuary at Tongue Point, Oregon

    Energy Technology Data Exchange (ETDEWEB)

    Young, J.S.; Word, J.Q.; Apts, C.W.; Barrows, M.E.; Cullinan, V.I.; Kohn, N.P.

    1988-12-01

    The Department of Economic Development, Ports Division, of the state of Oregon plans to develop a former ship supply and storage site near Tongue Point, Oregon, for commercial shipping. The development would require dredging the adjacent waterway to the Columbia River 40-foot channel to admit commercials vessels. The Portland District of the US Army Corps of Engineers requested the Battelle/Marine Sciences Laboratory (MSL) to conduct confirmatory solid-phase bioassays that would provide technical data for an evaluation of the potential environmental impact of ocean disposal of the dredged material. These confirmatory studies provided chemical and biological information required by ocean dumping regulations to determine suitability of Tongue Point sediments for ocean disposal. Sediment core samples were collected from Cathlamet Bay at Tongue Point in the upper Columbia River estuary. Sediment surface grab samples were collected at reference/control sites offshore from the mouth of the Columbia River (Disposal Site F) and at West Beach, Whidbey Island, Washington. The Tongue Point sediments were mixed into two composited batches. The MSL conducted solid-phase bioassays with these composites and reference sediments on four species of organisms.

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

    Science.gov (United States)

    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

  18. A multi-band semi-analytical algorithm for estimating chlorophyll-a concentration in the Yellow River Estuary, China.

    Science.gov (United States)

    Chen, Jun; Quan, Wenting; Cui, Tingwei

    2015-01-01

    In this study, two sample semi-analytical algorithms and one new unified multi-band semi-analytical algorithm (UMSA) for estimating chlorophyll-a (Chla) concentration were constructed by specifying optimal wavelengths. The three sample semi-analytical algorithms, including the three-band semi-analytical algorithm (TSA), four-band semi-analytical algorithm (FSA), and UMSA algorithm, were calibrated and validated by the dataset collected in the Yellow River Estuary between September 1 and 10, 2009. By comparing of the accuracy of assessment of TSA, FSA, and UMSA algorithms, it was found that the UMSA algorithm had a superior performance in comparison with the two other algorithms, TSA and FSA. Using the UMSA algorithm in retrieving Chla concentration in the Yellow River Estuary decreased by 25.54% NRMSE (normalized root mean square error) when compared with the FSA algorithm, and 29.66% NRMSE in comparison with the TSA algorithm. These are very significant improvements upon previous methods. Additionally, the study revealed that the TSA and FSA algorithms are merely more specific forms of the UMSA algorithm. Owing to the special form of the UMSA algorithm, if the same bands were used for both the TSA and UMSA algorithms or FSA and UMSA algorithms, the UMSA algorithm would theoretically produce superior results in comparison with the TSA and FSA algorithms. Thus, good results may also be produced if the UMSA algorithm were to be applied for predicting Chla concentration for datasets of Gitelson et al. (2008) and Le et al. (2009).

  19. Pathways of organic matter through food webs of diverse habitats in the regulated Nakdong River estuary (Korea)

    Science.gov (United States)

    Choy, Eun Jung; An, Soonmo; Kang, Chang-Keun

    2008-06-01

    The benthic macroinvertebrates of the Nakdong River estuary were sampled at three different habitats: two salt marsh ( Scirpus triqueter and Phragmites australis) beds and a bare intertidal flat. Fishes were sampled in the main channel. The trophic importance of marsh vascular plants, microphytobenthos, and riverine and channel particulate organic matter to macroinvertebrate and fish production was studied using stable carbon and nitrogen isotope tracers. There was a dramatic change in coverage of macrophytes (salt marshes and seagrass) after the construction of an estuarine barrage in 1987 in the Nakdong River estuary, with the S. triqueter bed increasing, the P. australis bed decreasing, and Zostera marina habitats being nearly lost. Although the invertebrate δ 13C were within a narrower range than those of the primary producers, the values varied considerably among consumers in these habitats. However, the isotope signatures of consumers showed similarities among different habitats. Cluster analysis based on their isotopic similarity suggested that the isotope variability among species was related more to functional feeding groups than to habitats or taxonomic groups. While δ 13C values of suspension feeders were close to that of the channel POM (mainly phytoplankton), other benthic feeders and predators had δ 13C similar to that of microphytobenthos. Isotopic mixing model estimates suggest that algal sources, including microphytobenthos and phytoplankton, play an important role in supporting the benthic food web. Despite the huge productivity of emergent salt marshes, the contribution of the marsh-derived organic matter to the estuarine food webs appears to be limited to some nutrition for some invertebrates just within marsh habitats, with little on the bare intertidal flats or in the channel fish communities. Isotope signatures of the channel fishes also confirm that algal sources are important in supporting fish nutrition. Our findings suggest that

  20. Pollution status of polycyclic aromatic hydrocarbons in surface sediments from the Yangtze River Estuary and its adjacent coastal zone.

    Science.gov (United States)

    Wang, Chenglong; Zou, Xinqing; Gao, Jianhua; Zhao, Yifei; Yu, Wenwen; Li, Yali; Song, Qiaochu

    2016-11-01

    Polycyclic aromatic hydrocarbons (PAHs) are mainly produced by incomplete combustion and are used as indicators of anthropogenic activities on the environment. This study analyses the PAHs level in the Yangtze River Estuary (YRE), an important component of Yangtze River and a developed and populated region in China. Surface sediments were collected from 77 sites at the YRE and its adjacent coastal zone (IACZ) for a comprehensive study of PAHs. Kriging interpolation technology and Positive matrix factorization (PMF) model were applied to explore the spatial distribution and sources of PAHs. Concentrations of 16 PAHs (ΣPAHs) varied from 27.2 ng g(-1) to 621.6 ng g(-1) dry weight, with an average value of 158.2 ng g(-1). Spatially, ΣPAHs exhibited wide fluctuation and exhibited an increasing tendency from north to south. In addition, ΣPAHs exhibited a decreasing trend with increasing distance between the estuary and IACZ. The deposition flux of PAHs indicated that more than 107.8 t a(-1) PAHs was deposited in the study area annually. The results of the PMF model revealed that anthropogenic activities were the main sources of PAHs in the study area. Vehicle emissions and marine engines were the most important sources and accounted for 40.9% of the pollution. Coal combustion, petrogenic sources, and wood combustion were other sources that contributed 23.9%, 23.6%, and 11.5%, respectively. The distribution patterns of PAHs in the YRE and IACZ were influenced by many complicated factors such as sediment grain size, hydrodynamics and so on. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Shoreline-change Rates of the Barrier Islands in Nakdong River Estuary Using Aerial Photography and SPOT-5 Image

    Directory of Open Access Journals (Sweden)

    Sang-Hun Jeong

    2013-03-01

    Full Text Available Shoreline data of the barrier islands in Nakdong River Estuary for the last three decades wereassembled using six sets of aerial photographs and seven sets of satellite images. Canny Algorithm wasapplied to untreated data in order to obtain a wet-dry boundary as a proxy shoreline. Digital ShorelineAnalysis System (DSAS 4.0 was used to estimate the rate of shoreline changes in terms of five statisticalvariables; SCE (Shoreline Change Envelope, NSM (Net Shoreline Movement, EPR(End Point Rate, LRR(Linear Regression Rate, and LMS (Least Median of Squares. The shoreline in Jinwoodo varieddifferently from one place to another during the last three decades; the west tail has advanced (i.e., seawardor southward, the west part has regressed, the south part has advanced, and the east part has regressed.After the 2000s, the rate of shoreline changes (−2.5~6.7 m/yr increased and the east advanced. Theshoreline in Shinjado shows a counterclockwise movement; the west part has advanced, but the east part hasretreated. Since Shinjado was built in its present form, the west part became stable, but the east part hasregressed faster. The rate of shoreline changes (−16.0~12.0 m/yr in Shinjado is greater than that ofJinwoodo. The shoreline in Doyodeung has advanced at a rate of 31.5 m/yr. Since Doyodeung was built inits present form, the south part has regressed at the rate of −18.2 m/yr, but the east and west parts haveadvanced at the rate of 13.5~14.3 m/yr. Based on Digital Shoreline Analysis, shoreline changes in thebarrier islands in the Nakdong River Estuary have varied both temporally and spatially, although the exactreason for the shoreline changes requires more investigation.

  2. Distribution and abundance of Cladocera (Branchiopoda in the Paraíba do Sul River estuary, Rio de Janeiro, Brazil

    Directory of Open Access Journals (Sweden)

    José Mauro Sterza

    2006-12-01

    Full Text Available To characterize the cladoceran community of the Paraíba do Sul River estuary, located in the district of São João da Barra, Rio de Janeiro, Brazil, cladocerans were collected monthly in nine sampling stations from September 2002 until August 2003. Samples were obtained by subsurface tows using a plankton net with a 30 cm opening mouth and 70 micron mesh size, fitted with a mechanical flowmeter. Environmental parameters such as salinity and temperature were also obtained. Seventeen species of Cladocera were identified: Pseudoevadne tergestina, Penilia avirostris, Macrothrix triserialis, Moina micrura, Simocephalus kerhervei, Simocephalus vetalus, Simocephalus latirostris, Simocephalus serrulatus, Alona rectangula, Alona quadrangularis, Bosmina longirostris, Bosminopsis deitersi, Camptocercus dadayi, Ceriodaphnia richardi, Diaphanosoma fluviatile, Kurzia latissima and Pleuroxus similis. The highest total abundance of Cladocera occurred in April in the marine zone of the estuary. The most abundant species during this period was Penilia avirostris. At the mixing and freshwater zones of the estuary, the most abundant species were Moina micrura, mainly in January; and Simocephalus vetalus and Bosmina longirostris during spring. From this scenario, it can be inferred that the cladoceran community of the Paraíba do Sul River estuary presents characteristics of marine, brackish and freshwater environments. Temperature and salinity seem to limit the occurrence and distribution of cladocerans in the estuary.O presente estudo teve como objetivo caracterizar a comunidade zooplanctônica de cladóceros no estuário do Rio Paraíba do Sul, localizado no município de São João da Barra, RJ. O zooplâncton foi coletado mensalmente de setembro/2002 a agosto/2003 em nove estações através de arrastos subsuperficiais com uma rede de plâncton com abertura de boca de 30 cm e malha de 70 mµ, dotada de fluxômetro mecânico. Foram medidas simultaneamente a

  3. Contribution to the determination of the place of death by drowning - A study of diatoms' biodiversity in Douro river estuary.

    Science.gov (United States)

    Coelho, Sara; Ramos, Patrícia; Ribeiro, Cláudia; Marques, Joana; Santos, Agostinho

    2016-07-01

    The role of the investigation of diatoms' presence in organs and body fluids of an individual found dead in a liquid medium and the relevant contribution to the forensic diagnosis of drowning remain controversial. Furthermore, the absence of an exact and well-defined method for diatoms' analysis makes its study a challenging task. Considering this medico-legal problem and the absence of forensic studies on this subject in Portugal, this work aimed to determine the drowning place of dead individuals based on the analysis of diatom species found in different tissues (lung, liver, kidney, bone marrow) and stomach content. Diatom species found in biological samples were compared with those present in the liquid medium where the corpses were found. A total of 37 cases of death by drowning in Oporto metropolitan area were studied. A seasonal database of the diatom species found in Douro river estuary was built based on water samples collected at nine selected places. Diatoms' extractions were performed by a chemical method using 37% (w/w) hydrochloridric acid for the biological samples and 96% (w/w) sulfuric acid for water samples. Diatoms were found in 63% of total cases but only in lung and gastric content samples. The absence of diatoms in other organs is probably related with a quick death, which may have stopped blood circulation almost immediately, preventing diatom contamination of the other organs. A strong relationship between the diatom species found in the biological samples and those found in water samples of the respective drowning place was observed. Due to the high anthropogenic influence on the Douro estuary no significant differences were observed between the five sampling places, making it extremely difficult to determine the exact estuary location of the drowning. The importance of the creation of a diatom database of the potential drowning places (e.g., rivers, seas, lakes) becomes clear in this study. It also shows that, in cases of drowning, the

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

    DEFF Research Database (Denmark)

    Hauptmann, Aviaja Zenia Edna Lyberth; Markussen, Thor N; Stibal, Marek

    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...... 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...

  5. Current meter data from moored current meter casts in the Columbia River estuary - Washington/Oregon as part of the Low Level Waste Ocean Disposal project from 13 August 1979 - 27 September 1984 (NODC Accession 9500016)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Current meter data were collected using moored current meter casts in the Columbia River estuary - Washington/Oregon from August 13, 1979 to September 27, 1984. Data...

  6. Microstructure, CTD and ADCP data collected from R/V ONRUST in Hudson River Estuary during 6 short cruises from 1994-05-19 to 2001-05-01 (NCEI Accession 0146260)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Observations of turbulent mixing, stratification and currents in the Hudson River Estuary made in 6 short cruises in 1994/1995 and 2001 were assembled. The lower...

  7. RESGPSPNTS_JD136.SHP: Navigation and Bathymetry Points of Ship Position During Continuous Resistivity Profile Data Collection in the Corsica River Estuary, Maryland on May 16, 2007 on USGS Cruise 07005

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Submarine groundwater discharge (SGD) into Maryland's Corsica River Estuary was investigated as part of a larger study to determine the importance of nutrient...

  8. RESGPSLNS_JD135.SHP: Ship Trackline along which Continuous Resistivity Profile Data were Collected in the Corsica River Estuary, Maryland on May 15, 2007 on USGS Cruise 07005

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Submarine groundwater discharge (SGD) into Maryland's Corsica River Estuary was investigated as part of a larger study to determine the importance of nutrient...

  9. MRG2007_CORSICA_ALLXYZ.SHP: Processed Continuous Resistivity Profile (CRP) Data Below the Sediment Water Interface From the Corsica River Estuary, Maryland Collected from May 15 to May 17, 2007 on USGS Cruise 07005

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Submarine groundwater discharge (SGD) into Maryland's Corsica River Estuary was investigated as part of a larger study to determine the importance of nutrient...

  10. RESGPSLNS_JD136.SHP: Ship Trackline along which Continuous Resistivity Profile Data were Collected in the Corsica River Estuary, Maryland on May 16, 2007 on USGS Cruise 07005

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Submarine groundwater discharge (SGD) into Maryland's Corsica River Estuary was investigated as part of a larger study to determine the importance of nutrient...

  11. RESGPSPNTS_JD135.SHP: Navigation and Bathymetry Points of Ship Position During Continuous Resistivity Profile Data Collection in the Corsica River Estuary, Maryland on May 15, 2007 on USGS Cruise 07005

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Submarine groundwater discharge (SGD) into Maryland's Corsica River Estuary was investigated as part of a larger study to determine the importance of nutrient...

  12. RESGPSPNTS_JD137.SHP: Navigation and Bathymetry Points of Ship Position During Continuous Resistivity Profile Data Collection in the Corsica River Estuary, Maryland on May 17, 2007 on USGS Cruise 07005

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Submarine groundwater discharge (SGD) into Maryland's Corsica River Estuary was investigated as part of a larger study to determine the importance of nutrient...

  13. RESGPSLNS_JD137.SHP: Ship Trackline along which Continuous Resistivity Profile Data were Collected in the Corsica River Estuary, Maryland on May 17, 2007 on USGS Cruise 07005

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Submarine groundwater discharge (SGD) into Maryland's Corsica River Estuary was investigated as part of a larger study to determine the importance of nutrient...

  14. Benthic studies in Goa estuaries. I. Standing crop and faunal composition in relation to bottom salinity distribution characteristics in the estuary of Mandovi River

    Digital Repository Service at National Institute of Oceanography (India)

    Parulekar, A.H.; Dwivedi, S.N.

    Macrobenthos in Mandovi, Cumbarjua canal and Zuari estuaries, a physically interconnected tropical estuarine system which undergoes large seasonal changes in salinity distribution due to heavy monsoonal precipitation, is very rich (111 species...

  15. The source of natural and anthropogenic heavy metals in the sediments of the Minjiang River Estuary (SE China): implications for historical pollution.

    Science.gov (United States)

    Xu, Yonghang; Sun, Qinqin; Yi, Liang; Yin, Xijie; Wang, Aijun; Li, Yunhai; Chen, Jian

    2014-09-15

    Two sedimentary cores in the Minjiang River estuary (SE China) are documented for grain size, clay minerals, heavy metals, magnetic parameters and Pb isotopes to investigate the source and historical variation of heavy metals. The MJK9 core was collected outside of the Minjiang River estuary, and the core is composed of mixed sediments, of which ~70% from the Yangtze River and 30% from the Minjiang River. It is thus difficult to be used for tracing the human activity along the Minjiang River. In contrast, the sediments of MJK16 core which was collected in a nearshore area are primarily from the Minjiang River. The enrichment factors of the sediments were pollution. The results indicate that the sediments of the MJK16 core have Cu and Pb concentrations increasing since 1980, associated with the increase of magnetic mineral concentration and (206)Pb/(207)Pb and (206)Pb/(208)Pb of the sediments. We compared the Pb isotopic compositions between our results and those for the deposit mining in the Minjiang River basin, and aerosols and coal dust in south China, and considered that Pb in the sediments of the MJK16 core was derived primarily from weathered rocks as well as industrial emission (e.g. coal combustion). The sediments have anthropogenic Pb concentrations ranging from 6% in 1950 to 23.7% in 2010, consistent with the impact of rapid urban and industrial development in China.

  16. 长江口水域悬沙浓度时空变化与泥沙再悬浮%Temporal and spatial changes of suspended sediment concentration and resuspension in the Yangtze River estuary

    Institute of Scientific and Technical Information of China (English)

    陈沈良; 张国安; 杨世伦

    2003-01-01

    A detailed analysis of suspended sediment concentration (SSC) variations over a year period is presented using the data from 8 stations in the Yangtze River estuary and its adjacent waters, together with a discussion of the hydrodynamic regimes of the estuary. Spatially, the SSC from Xuliujing downwards to Hangzhou Bay increases almost constantly, and the suspended sediment in the inner estuary shows higher concentration in summer than in winter, while in the outer estuary it shows higher concentration in winter than in summer, and the magnitude is greater in the outer estuary than in the inner estuary, greater in the Hangzhou Bay than in the Yangtze River estuary.The sediments discharged by the Yangtze River into the sea are resuspended by marine dynamics included tidal currents and wind waves. Temporally, the SSC shows a pronounced neap-spring tidal cycle and seasonal variations. Furthermore, through the analysis of dynamic mechanism, it is concluded that wave and tidal current are two predominant factors of sediment resuspension and control the distribution and changes of SSC, in which tidal currents control neap-spring tidal cycles,and wind waves control seasonal variations. The ratio between river discharge and marine dynamics controls spatial distribution of SSC.

  17. Benthic Bacillariophyta of the Paripe River estuary in Pernambuco state, Brazil

    Directory of Open Access Journals (Sweden)

    AN. Moura

    Full Text Available The aim of this study was to evaluate the benthic diatom composition from the estuary sediment in the Pernambuco State, based on 32 samples. Samples were collected monthly from September through December 1999 (dry period and from April through July 2000 (rainy period during four pre established sampling stations. Results indicated 19 families and 31 specific and infraspecific taxa. Eight new records were founded for Pernambuco State: Auliscus coelatus, Fallacia nummularia, Navicula algida, Plagiograma pulchellum, Terpsinoe americana, Triceratium antideluvianna and Tryblionella coarctata and one, Auliscus punctatus Bailey, in northeastern Brazil.

  18. Surface water characteristics and trace metals level of the Bonny/New Calabar River Estuary, Niger Delta, Nigeria

    Science.gov (United States)

    Onojake, M. C.; Sikoki, F. D.; Omokheyeke, O.; Akpiri, R. U.

    2017-05-01

    Surface water samples from three stations in the Bonny/New Calabar River Estuary were analyzed for the physicochemical characteristics and trace metal level in 2011 and 2012, respectively. Results show pH ranged from 7.56 to 7.88 mg/L; conductivity, 33,489.00 to 33,592.00 µScm-1; salinity, 15.33 to 15.50 ‰; turbidity, 4.35 to 6.65 NTU; total dissolved solids, 22111.00 to 23263.00 gm-3; dissolved oxygen, 4.53 to 6.65 mg/L; and biochemical oxygen demand, 1.72 mg/L. The level of some trace metals (Ca, Mg, K, Zn, Pb, Cd, Co, Cr, Cu, Fe, Ni, and Na) were also analyzed by Atomic absorption spectrometry with K, Zn, and Co being statistically significant ( P Concentrations of trace metals such as Pb, Cd, Zn, Ni, and Cr were higher than stipulated limits by WHO (2006). The result of the Metal Pollution Index suggests that the river was slightly affected and therefore continuous monitoring is necessary to avert possible public health implications of these metals on consumers of water and seafood from the study area.

  19. Surface water characteristics and trace metals level of the Bonny/New Calabar River Estuary, Niger Delta, Nigeria

    Science.gov (United States)

    Onojake, M. C.; Sikoki, F. D.; Omokheyeke, O.; Akpiri, R. U.

    2015-07-01

    Surface water samples from three stations in the Bonny/New Calabar River Estuary were analyzed for the physicochemical characteristics and trace metal level in 2011 and 2012, respectively. Results show pH ranged from 7.56 to 7.88 mg/L; conductivity, 33,489.00 to 33,592.00 µScm-1; salinity, 15.33 to 15.50 ‰; turbidity, 4.35 to 6.65 NTU; total dissolved solids, 22111.00 to 23263.00 gm-3; dissolved oxygen, 4.53 to 6.65 mg/L; and biochemical oxygen demand, 1.72 mg/L. The level of some trace metals (Ca, Mg, K, Zn, Pb, Cd, Co, Cr, Cu, Fe, Ni, and Na) were also analyzed by Atomic absorption spectrometry with K, Zn, and Co being statistically significant (P salinity during the dry season than wet season. Concentrations of trace metals such as Pb, Cd, Zn, Ni, and Cr were higher than stipulated limits by WHO (2006). The result of the Metal Pollution Index suggests that the river was slightly affected and therefore continuous monitoring is necessary to avert possible public health implications of these metals on consumers of water and seafood from the study area.

  20. Virio- and bacterioplankton in the estuary zone of the Ob River and adjacent regions of the Kara Sea shelf

    Science.gov (United States)

    Kopylov, A. I.; Sazhin, A. F.; Zabotkina, E. A.; Romanenko, A. V.; Romanova, N. D.

    2017-01-01

    The distribution of structural and functional characteristics of virioplankton in the north of the Ob River estuary and the adjacent Kara Sea shelf (between latitudes 71°44'44″ N and 73°45'24″ N) was studied with consideration of the spatial variations in the number ( N B) and productivity ( P B) of bacteria and water properties (temperature, salinity, density) by analyzing samples taken in September 2013. The number of plankton viruses ( N V), the occurrence of visible infected bacteria cells, virus-induced mortality of bacteria, and virioplankton production in the studied region varied within (214-2917) × 103 particles/mL, 0.3-5.6% of NB, 2.2-64.4% of P B, and (6-17248) × 103 particles/(mL day), respectively. These parameters were the highest in water layers with a temperature of +7.3-7.5°C, salinity of 3.75-5.41 psu, and conventional density (στ) of 2.846-4.144. The number of bacterioplankton was (614-822) × 103 cells/mL, and the N V/ N B ratio was 1.1-4.5. A large amount of virus particles were attached to bacterial cells and suspended matter. The data testify to the considerable role of viruses in controlling the number and production of heterotrophic bacterioplankton in the interaction zone of river and sea waters.

  1. Distributions and source apportionment of sediment-associated polycyclic aromatic hydrocarbons (PAHs) and hopanes in rivers and estuaries of Peninsular Malaysia.

    Science.gov (United States)

    Keshavarzifard, Mehrzad; Zakaria, Mohamad Pauzi; Hwai, Tan Shau; Yusuff, Ferdius Mohamat; Mustafa, Shuhaimi

    2015-06-01

    In this study, the distributions and sources of sediment-associated polycyclic aromatic hydrocarbons (PAHs) and hopanes in the Malaysian rivers and estuaries were evaluated. The concentrations of 16 USEPA PAHs varied from 225.5 to 293.9 (Perlis River), 195.2 to 481.2 (Kedah River), 791.2 to 1995.4 (Merbok River), 231.2 to 426.7 (Perak River), and 3803.2 to 7442.7 ng g(-1) (Klang River) dry weight. PAHs can be classified as moderate in the Perlis, Kedah, and Perak Rivers, moderate to high in the Merbok River, and high to very high in the Klang River. The comparison of PAHs with sediment quality guidelines (SQGs) indicates that occasionally adverse biological effects may occur from total PAHs, low molecular weight (LMW), and high molecular weight (HMW) PAHs at stations 1, 2, and 3 of the Klang River and from total PAHs at station 2 of the Merbok River. The diagnostic ratios of individual PAHs indicate both petrogenic and pyrogenic origin PAHs with significant dominance of pyrogenic sources in the study areas. The results suggest that Malaysian sediments had hopane ratios (C29/C30) similar to MECO suggesting MECO as a major source of the petroleum hydrocarbons found in the sediments, which is consistent with results reported in previous studies. These findings demonstrate that effective and improved environmental regulations in Malaysia have shifted the source of petroleum hydrocarbons from petrogenic to pyrogenic origin.

  2. Feeding ecology and trophic relationships of fish species in the lower Guadiana River Estuary and Castro Marim e Vila Real de Santo António Salt Marsh

    Science.gov (United States)

    Sá, Rita; Bexiga, Constança; Veiga, Pedro; Vieira, Lina; Erzini, Karim

    2006-10-01

    In this study we analyze the feeding ecology and trophic relationships of some of the main fish species (Soleidae, Moronidae, Mullidae, Sparidae, Mugilidae, and Batrachoididae) of the lower Estuary of the Guadiana River and the Castro Marim e Vila Real de Santo António Salt Marsh. We examined the stomachs of 1415 fish caught monthly between September 2000 and August 2001. Feeding indices and coefficients were determined and used along with the results of multivariate analysis to develop diagrams of trophic interactions (food webs). Results show that these species are largely opportunistic predators. The most important prey items are amphipods, gobies (Gobiidae), shrimps ( Palaemon serratus and Crangon crangon), and polychaete worms. The lower Estuary and associated salt marshes are important nurseries and feeding grounds for the species studied. In this area, it is therefore important to monitor the effects of changes in river runoff, nutrient input, and temperature that result from construction of the Alqueva Dam upstream.

  3. Dissolved and particulate Barium in the Ganga (Hooghly) River estuary, India: Solute-particle interactions and the enhanced dissolved flux to the oceans

    Science.gov (United States)

    Samanta, Saumik; Dalai, Tarun K.

    2016-12-01

    In this study, the sources and the cycling of Ba have been evaluated in the Ganga (Hooghly) River estuary using the composition of the suspended sediments and the water samples collected during six seasons of contrasting water discharge over two years (2012 and 2013). In addition, the data on the samples of groundwater from areas adjacent to the estuary, and the industrial effluent water and urban wastewater draining into the estuary are presented. Selective extraction experiments were also performed on the suspended particulate matter of two seasons to assess the distribution of exchangeable concentrations of major ions and Ba. In the mixing zone, the variation patterns of the dissolved Ba concentrations show mid-salinity maxima and are similar to the patterns of variation of the particulate Mg/Al and Mg/Fe, suggesting that the production of dissolved Ba is linked to the adsorption of major ions on to the clay minerals and Fe-Mn oxyhydroxides in the particulate matter. The inference of coupled adsorption-desorption processes is supported by the observations that the particulate Ba/Mg and Ba/K ratios exhibit significant to strong negative correlations with the concentrations of Al, Fe and Mn. The observations of mid-salinity maxima for the concentrations of exchangeable Mg and K, and of the exchangeable Ba concentrations that decrease with salinity provide strong evidence that the solute-particle interactions is the major driver in regulating the dissolved Ba distributions in the estuary. The estimates of the quantity of desorbed Ba based on three different approaches suggest that desorption is sufficient to account for the calculated excess Ba (Baxs) concentrations. The contribution of Ba to the dissolved load via dissolution of the particulate carbonate phases is minor, up to 3% of the maximum Baxs concentrations. The estimates of anthropogenic contributions are insignificant, and account for ⩽2% of maximum Baxs in the estuary. Groundwater contributions are

  4. Genetic and biogeochemical investigation of sedimentary nitrogen cycling communities responding to tidal and seasonal dynamics in Cape Fear River Estuary

    Science.gov (United States)

    Lisa, Jessica A.; Song, Bongkeun; Tobias, Craig R.; Hines, David E.

    2015-12-01

    Tidal and seasonal fluctuations in the oligohaline reaches of estuaries may alter geochemical features that influence structure and function of microbial communities involved in sedimentary nitrogen (N) cycling. In order to evaluate sediment community responses to short-term (tidal) and long-term (seasonal) changes in different tidal regimes, nitrogen cycling rates and genes were quantified in three sites that span a range of tidal influence in the upper portion of the Cape Fear River Estuary. Environmental parameters were monitored during low and high tides in winter and spring. 15N tracer incubation experiments were conducted to measure nitrification, denitrification, anaerobic ammonium oxidation (anammox), and dissimilatory nitrate reduction to ammonia (DNRA). Abundances of functional genes including bacterial and archaeal ammonia monooxygenase (amoA), nitrite reductases (nirS and nrfA), nitrous oxide reductase (nosZ), and hydrazine oxidoreductase (hzo) were measured using quantitative PCR assays. Denitrification rates were highest among the measured N cycling processes while bacteria carrying nrfA genes were most abundant. A discernable pattern in the short-term variation of N cycling rates and gene abundance was not apparent under the different tidal regimes. Significant seasonal variation in nitrification, denitrification, and anammox rates as well as bacterial amoA, nirS and nosZ gene abundance was observed, largely explained by increases in substrate availability during winter, with sediment ammonium playing a central role. These results suggest that the coupling of nitrification to N removal pathways is primarily driven by organic carbon mineralization and independent of tidal or salinity changes. Finally, changes in denitrification and nitrification activities were strongly reflected by the abundance of the respective functional genes, supporting a linkage between the structure and function of microbial communities.

  5. Uptake and distribution of N, P and heavy metals in three dominant salt marsh macrophytes from Yangtze River estuary, China.

    Science.gov (United States)

    Quan, W M; Han, J D; Shen, A L; Ping, X Y; Qian, P L; Li, C J; Shi, L Y; Chen, Y Q

    2007-07-01

    We examined the variation in aboveground biomass accumulation and tissue concentrations of nitrogen (N), phosphorus (P), copper (Cu), zinc (Zn) and lead (Pb) in Phragmites australis (common reed), Spartina alterniflora (salt cordgrass), and Scirpus mariqueter throughout the growing season (April-October 2005), in order to determine the differences in net element accumulation and distribution between the three salt marsh macrophytes in the Yangtze River estuary, China. The aboveground biomass was significantly greater in the plots of S. alterniflora than in the plots of P. australis and S. mariqueter throughout the growing season (Pbiomass was 1246+/-89 gDW/m(2), 2759+/-250 gDW/m(2) and 548+/-54 gDW/m(2) for P. australis, S. alterniflora and S. mariqueter, respectively. The concentrations of nutrients and heavy metals in plant tissues showed similar seasonal patterns. There was a steady decline in element concentrations of the aboveground tissues from April to October. Relative element concentrations in aboveground tissues were at a peak during the spring sampling intervals with minimum levels during the fall. But the concentrations of total nitrogen and total phosphorus in the belowground tissues were relatively constant throughout growing season. Generally, trace metal concentrations in the aboveground tissues of S. mariqueter was the highest throughout the growing season, and the metal concentrations of S. alterniflora tissues (aboveground and belowground) were greater than those of P. australis. Furthermore, the aboveground pools of nutrients and metals were consistently greater for S. alterniflora than for P. australis and S. mariqueter, which suggested that the rapid replacement of native P. australis and S. mariqueter with invasive S. alterniflora would significantly improve the magnitude of nutrient cycling and bioavailability of trace metals in the salt marsh and maybe transport more toxic metals into the water column and the detrital food web in the

  6. Variations and net transport of dissolved inorganic nutrients in the South Passage of the Changjiang (Yangtze River) Estuary

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Dissolved inorganic nutrient elements were analyzed from the samples collected in the South Passage of the Changjiang (Yangtze River) Estuary in March 2003, including NH4+, NO3-, NO2- and PO43-. The water samples were collected with a Niskin sampler hourly at the near-surface, middle and near-bottom depths at the three stations-A1, A2 and A3-during two complete tidal cycles of neap tide and spring tide. Results showed that 1) the concentrations of NH4+, NO3- and NO2- were a little higher respectively during the neap tide than those during the spring tide, while PO43- showed an opposite trend, and each was higher in the ebb tide than in the flood tide, either for the neap tidal cycle or the spring tidal cycle; 2) higher stratification of the nutrients existed obviously in this area, with the concentrations of which increased from the bottom to the surface, especially for NH4+ and NO3-; 3) the coefficient of variation (C.V.) values of all dissolved inorganic nutrients varied from 4.06% to 36.8% beyond different influences of the tidal current and Changjiang runoff; 4) with increasing suspended matter in the water column, the concentrations of PO43- became lower in the filtered water; and 5) the total transport of each tidal cycle was much more in the spring tide than in the neap tide, and the positive values indicated that the nutrients had been exported to the East China Sea. Studies on the variations and net transport of dissolved inorganic nutrients in the South Passage of the Changjiang Estuary will provide the scientific basis for the study of the mechanism of red tide in the East China Sea.

  7. Persistent organochlorines in beluga whales (Delphinapterus leucas) from the St Lawrence River estuary--II. Temporal trends, 1982-1994.

    Science.gov (United States)

    Muir, D C; Koczanski, K; Rosenberg, B; Béland, P

    1996-01-01

    Blubber samples from 16 dead beluga whales (Delphinapterus leucas) collected during 1993-1994 in the St Lawrence River estuary were analysed for PCB congeners and other persistent organochlorines (DDT-group, chlorinated bornanes (toxaphene, CHB), chlordane SigmaCHL), hexachloro-cyclohexanes (SigmaHCH), chlorobenzenes (SigmaCBz), tris(p-chlorophenyl methane (TPMe) and mirex). Concentrations and relative proportions of major individual organochlorine components were within the same range as previous results for this population. Temporal trends were studied by combining the results with data from the analysis of 44 samples (1986-1990) and (for DDT and Aroclor PCBs only) with 20 samples (1982-1985) reported by Martineau et al., 1987. Results were lipid normalized and then age-adjusted by an ANCOVA model. Significant relationships between age and concentrations of most organochlorine groups were found for females but not for males. Significant declines were observed in SigmaDDT, and Aroclor PCBs (1.5- and 1.9-fold, respectively) in males between the 1982-1985 and 1993-1994 collection periods. Significant declines were also observed for SigmaHCH and SigmaCBz in males between 1986-1988 and 1993-1994. Mean concentrations of CHBs were significantly higher in 1993-1994 than in earlier years while dieldrin, SigmaCHL, mirex, and TPMe showed no trend. Declines in concentrations of major organochlorine groups were not observed in females possibly because of higher year to year, and within year, variation. The temporal trend in DDT and PCB concentrations in male beluga blubber paralleled trends in seals, eels, and seabirds in the St Lawrence estuary observed during the 1980s.

  8. Composition of shrimp populations (Crustacea: Decapoda in non-vegetated areas of two river islands in a Brazilian Amazon estuary

    Directory of Open Access Journals (Sweden)

    Priscila Sousa Vilela da Nóbrega

    2013-12-01

    Full Text Available This study investigates the shrimp found in non-vegetated areas of an estuary of the Amazon River. We ascertained the input of juveniles, species' biometrics and the influence of environmental factors on the abundance of species. The samples were collected monthly, from August 2006 to July 2007, in two places in the estuary, each next to an island. For collecting, we used a manual trawl to perform three hauls per month, totaling 36 samples per site. The abundance of shrimps was estimated as a function of the density of specimens per unit area. We used the Spearman's correlation to test the hypothesis that there is significant correlation between the average of the environmental variables measured and variations in shrimp density. The Kruskal-Wallis and the Mann-Whitney tests showed that there were significant differences in environment factors (temperature and salinity among the months and sites. We obtained 6,091 shrimps, from which 5,231 (85.88% were caught off the Arapiranga Island and 860 (14.12% off the Mosqueiro Island, Palaemonidae and Penaeidae were the only families recorded. Five species were collected: Macrobrachium amazonicum (Heller, 1862, Macrobrachium surinamicum Holthuis, 1948, Macrobrachium carcinus (Linnaeus, 1758, Macrobrachium rosenbergii (De Man, 1879, and Farfantepenaeus subtilis (Pérez-Farfante, 1967. The latter (pink shrimp was found for the first time in oligohaline environments (0-8. Macrobrachium amazonicum was the most abundant species. The recruitment of M. amazonicum juveniles was continuous throughout the year. The population of M. surinamicum was composed by juveniles and adults and that of F. subtilis exclusively by juveniles. The environmental factors analyzed were variable throughout the year and seem to explain the patterns of shrimp species occurrence in the region, the variation in their abundance and juvenile recruitment.

  9. Metagenomic evidence for reciprocal particle exchange between the mainstem estuary and lateral bay sediments of the lower Columbia River

    Directory of Open Access Journals (Sweden)

    Mariya W Smith

    2015-10-01

    Full Text Available Lateral bays of the lower Columbia River estuary are areas of enhanced water retention that influence net ecosystem metabolism through activities of their diverse microbial communities. Metagenomic characterization of sediment microbiota from three disparate sites in two brackish lateral bays (Baker and Youngs produced approximately 100 Gbp of DNA sequence data analyzed subsequently for predicted SSU rRNA and peptide-coding genes. The metagenomes were dominated by Bacteria. A large component of Eukaryota was present in Youngs Bay samples, i.e. the inner bay sediment was enriched with the invasive New Zealand mudsnail, Potamopyrgus antipodarum, known for high ammonia production. The metagenome was also highly enriched with an archaeal ammonia oxidizer closely related to Nitrosoarchaeum limnia. Combined analysis of sequences and continuous, high-resolution time series of biogeochemical data from fixed and mobile platforms revealed the importance of large-scale reciprocal particle exchanges between the mainstem estuarine water column and lateral bay sediments. Deposition of marine diatom particles in sediments near Youngs Bay mouth was associated with a dramatic enrichment of Bacteroidetes (58% of total Bacteria and corresponding genes involved in phytoplankton polysaccharide degradation. The Baker Bay sediment metagenome contained abundant Archaea, including diverse methanogens, as well as functional genes for methylotrophy and taxonomic markers for syntrophic bacteria, suggesting that active methane cycling occurs at this location. Our previous work showed enrichments of similar anaerobic taxa in particulate matter of the mainstem estuarine water column. In total, our results identify the lateral bays as both sources and sinks of biogenic particles significantly impacting microbial community composition and biogeochemical activities in the estuary.

  10. In situ fate and partitioning of waterborne perfluoroalkyl acids (PFAAs) in the Youngsan and Nakdong River Estuaries of South Korea

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Seongjin [School of Earth and Environmental Sciences, Seoul National University, Seoul (Korea, Republic of); Khim, Jong Seong, E-mail: jskocean@snu.ac.kr [School of Earth and Environmental Sciences, Seoul National University, Seoul (Korea, Republic of); Park, Jinsoon [School of Earth and Environmental Sciences, Seoul National University, Seoul (Korea, Republic of); Kim, Minhee; Kim, Woong-Ki; Jung, Jinho; Hyun, Seunghun; Kim, Jeong-Gyu [Division of Environmental Science and Ecological Engineering, Korea University, Seoul (Korea, Republic of); Lee, Hyojin; Choi, Heeseon J. [Department of Environmental Chemistry and Ecology, GeoSystem Research Corporation, Gunpo (Korea, Republic of); Codling, Garry [Department of Veterinary Biomedical Sciences and Toxicology Centre, University of Saskatchewan, Saskatoon, SK (Canada); Giesy, John P. [Department of Veterinary Biomedical Sciences and Toxicology Centre, University of Saskatchewan, Saskatoon, SK (Canada); Department of Zoology, Center for Integrative Toxicology, Michigan State University, East Lansing, MI (United States); Department of Biology and Chemistry and State Key Laboratory in Marine Pollution, City University of Hong Kong, Kowloon, Hong Kong, SAR (China)

    2013-02-15

    Concentrations, distributions, fate, and partitioning of perfluoroalkyl acids (PFAAs) were investigated in surface water (n = 34) collected from the Youngsan and Nakdong River Estuaries of South Korea. Thirteen individual PFAAs in water and suspended solids (SS) were quantified by use of HPLC–MS/MS. PFAAs were detected in all samples, which indicated that they were widely distributed in the study area. Greater concentrations of PFAAs were found at some inland sites which seemed to be affected by direct input from point sources, such as wastewater treatment plants, and/or indirect diffusive sources, such as surface runoff. Spatial distributions of PFAAs in estuaries along transects toward the open sea demonstrated that these chemicals were transported to the outer region primarily by water discharged during the rainy season. Field-based partition coefficients (K{sub d}) for long-chain PFAAs (C ≥ 8) were significantly correlated with salinity (r{sup 2} = 0.48 to 0.73, p < 0.01); K{sub d} values increased exponentially as a function of salinity. Due to the ‘salting-out’ effect, PFAAs were largely scavenged by adsorption onto SS and/or sediments in estuarine environments. In addition, values for K{sub d} of those PFAAs were directly proportional to the number of carbon atoms in the PFAAs. Salting constants of selected PFAAs were notably greater than those of other environmental organic contaminants, which indicated that adsorption of PFAAs is largely associated with salinity. Overall, the results of the present study will provide better understanding of the fate and transport of PFAAs in the zone of salinity boundary that can be used for developing fate models of PFAAs in the coastal marine environment. - Highlights: ► In situ fate and partitioning of PFAAs were described along salinity gradients in estuaries. ► Salinity was found to be the key factor controlling adsorption of waterborne PFAAs. ► The K{sub d} for longer-chain PFAAs (C ≥ 8) increased as

  11. Fate and source distribution of organic constituents in a river-dominated tropical estuary

    Indian Academy of Sciences (India)

    P M Salas; C H Sujatha; C S Ratheesh Kumar

    2015-08-01

    We investigated spatial and temporal changes in the quality of sedimentary organic matter and trophic status of the Cochin estuarine system, southwest coast of India. Sediment samples were collected in five sampling campaigns from January 2009 to April 2010. TOC/N ratio implied mixed input of autochthonous as well as remarkable allochthonous terrestrial higher plant debris into the sedimentary system. More depleted 13C values at riverine and industrial zone suggested a major contribution of terrestrial higher plant debris to sedimentary organic matter. Trophic status of the estuary changed seasonally to eutrophic via oligotrophic and mesotrophic conditions during the period January 2009 to April 2010. The protein to carbohydrate ratio was lower (<1), indicating heterotrophic nature and the higher lipid to carbohydrate ratio (>1) denoted preservation of lipid compounds in the sediments. Correlation analyses provide evidence of the association of chlorophyll pigments with carbohydrates and account for the highly productive nature of the estuary and algal contributions to organic matter. Canonical correspondence analysis clearly illustrated prominence of phaeopigments in fishing zone, lipids in sewage/tourism influenced zone, carbohydrates in riverine zone and proteins in industrial zone. It also indicated the influence of sedimentary texture, pH and organic carbon to the distribution of biochemical constituents.

  12. The response of a natural phytoplankton community from the Godavari River Estuary to increasing CO2 concentration during the pre-monsoon period

    Digital Repository Service at National Institute of Oceanography (India)

    Biswas, H.; Cros, A.; Yadav, K.; Ramana, V.V.; Prasad, V.R.; Acharyya, T.; Babu, P.V.R.

    also been reported by many authors (Trond et al., 2007; Currie and Kalff, 1984). Even diatoms can be out-done by bacteria during such conditions (Brussard and Riegman, 1998). However, the efficiency of bacteria in competing with phytoplankton..., cyanobacteria can easily compete with diatoms in a mixed population under high CO 2 supply and low silicate concentrations. 19 Conclusion: A natural phytoplankton community in the Godavari River Estuary was found to be quite sensitive to increasing CO...

  13. Mechanical Erosion in a Tropical River Basin in Southeastern Brazil: Chemical Characteristics and Annual Fluvial Transport Mechanisms

    Directory of Open Access Journals (Sweden)

    Alexandre Martins Fernandes

    2012-01-01

    Full Text Available This study aims to evaluate the mechanical erosion processes that occur in a tropical river basin, located in the São Paulo state, southeastern Brazil, through the chemical characterization of fine suspended sediments and the transport mechanisms near the river mouth, from March 2009 to September 2010. The chemical characterization indicated the predominance of SiO2, Al2O3, and Fe2O3 and showed no significant seasonal influences on the major element concentrations, expressed as oxides. The concentration variations observed were related to the mobility of chemical species. The evaluation of the rock-alteration degree indicated that the physical weathering was intense in the drainage basin. The fine suspended sediments charge was influenced by the variation discharges throughout the study period. The solid charge estimate of the surface runoff discharge was four times higher in the rainy season than the dry season. The transport of fine suspended sediments at the Sorocaba River mouth was 55.70 t km−2 a−1, corresponding to a specific physical degradation of 37.88 m Ma−1, a value associated with the mechanical erosion rate that corresponds to the soil thickness reduction in the drainage basin.

  14. Quality and Behavior of Juvenile Salmonids in the Columbia River Estuary and Nearshore Ocean and Effects of the Ocean Environment on the Survival of Columbia River Juvenile Salmonids, 1989-1994 Technical Report.

    Energy Technology Data Exchange (ETDEWEB)

    Francis, R.C.; Schiewe, Michael H.; Fisher, J.P.

    1989-05-01

    In response to this limited understanding of the factors responsible for the continuing decline of spring chinook salmon in the Columbia River, this research plan was developed. The overall goal of the proposed research is to investigate and identify relationships among smolt quality (measured in the hatchery and after recovery in the estuary and nearshore ocean), environmental conditions in the estuary and nearshore ocean during smolt migration, and long-term survival (as measured by adult returns to the hatchery of origin and contributions to the recreational, commercial, and tribal fisheries). 16 refs., 15 figs., 3 tabs.

  15. GEOTOURISM IN THE NIŠAVA RIVER MIDSTREAM VALLEY, SOUTHEASTERN SERBIA – CURRENT STATE AND ISSUES OF FUTURE DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    Milica Began

    2015-12-01

    Full Text Available The region of East  and Southeast Serbia, has the biggest collection of geoheritage sites in the Republic of Serbia. In the southeastern part of Serbia, following various mineralogical compositions of the rocks, the Nišava river has carved a composite valley. This is an area of extraordinary nature capacity because of large number of natural rarities and phenomena that have great possibilities for geotourism development. Despite exceptional predispositions in terms of the value of geological heritage, geosites of this area are still unknown to a wider audience. Aim of this paper is to analyze current state of geotourism and to highlight the values of geosites in Srednje Ponišavlje using the evaluating model as well to evaluate its quality and give the assessment of geotourism development success. Using GAM model, 7 geosites have been analyzed, the ones with extraordinary geological/geomorphological and hydrological features for geotourism development.

  16. Molecular Fingerprint and Dominant Environmental Factors of Nitrite-Dependent Anaerobic Methane-Oxidizing Bacteria in Sediments from the Yellow River Estuary, China

    Science.gov (United States)

    Yan, Pengze; Li, Mingcong; Wei, Guangshan; Li, Han; Gao, Zheng

    2015-01-01

    Nitrite-dependent anaerobic methane oxidation (n-damo) is performed by “Candidatus Methylomirabilis oxyfera” (M. oxyfera), which connects the carbon and nitrogen global nutrient cycles. In the present study, M. oxyfera-like bacteria sequences were successfully recovered from Yellow River Estuary sediments using specific primers for 16S rRNA and pmoA genes. A M. oxyfera-like sequences analysis based on the 16S rRNA gene revealed greater diversity compared with the pmoA gene; the 16S rRNA gene sequences retrieved from the Yellow River Estuary sediments belong to groups A as well as B and were mainly found in freshwater habitats. Quantitative PCR showed that 16S rRNA gene abundance varied from 9.28±0.11×103 to 2.10±0.13×105 copies g-1 (dry weight), and the pmoA gene abundance ranged from 8.63±0.50×103 to 1.83±0.18×105 copies g-1 (dry weight). A correlation analysis showed that the total organic carbon (TOC) and ammonium (NH4+) as well as the ratio of total phosphorus to total nitrogen (TP/TN) influenced the M. oxyfera-like bacteria distribution in the Yellow River Estuary sediments. These findings will aid in understanding the n-damo bacterial distribution pattern as well as their correlation with surrounding environmental factors in temperate estuarine ecosystems. PMID:26368535

  17. Past, Present, and Future Nutrient Quality of a Small Southeastern River: A Pre-Dam Assessment

    OpenAIRE

    Stewart, Paul M.; Miller, Jonathan M

    2013-01-01

    Riverine dams alter both the physical environment and water chemistry, thus affecting species assemblages within these environments. In the United States, dam construction is on the decline and there is a growing trend for dam removal. The Choctawhatchee, Pea, and Yellow Rivers Watershed Management Authority had initiated the permitting process for placing a reservoir dam on the Little Choctawhatchee River (LCR), a tributary to the Choctawhatchee River. The purpose of the proposed reservoir w...

  18. Long-term monitoring of metal pollution in sediments from the estuary of the Nerbioi-Ibaizabal River (2005-2010)

    Science.gov (United States)

    Gredilla, Ainara; Fdez-Ortiz de Vallejuelo, Silvia; Arana, Gorka; de Diego, Alberto; Madariaga, Juan Manuel

    2013-10-01

    This work aims to investigate the spatial and temporal distribution of trace metals in sediment samples taken from the Nerbioi-Ibaizabal River estuary (Bilbao, Basque Country) over the course of a long-term surveillance monitoring programme from 2005 to 2010. Sediment Quality Guidelines (SQGs) and the geoaccumulation indexes (Igeo) were used to assess the environmental risk posed by metal content in the estuary sediment. Sediment was collected at eight different sites in the estuary every three months over the period of investigation. A total of 14 elements (Al, As, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Sn, V and Zn) were selected and the concentration of each was measured in all samples. Additionally, conductivity, pH and the concentration of carbonate, total organic carbon and fulvic and humic acids were also measured in those samples collected in sampling campaigns from March 2006 to October 2008. The concentration of most of the metals systematically decreased over the period of investigation. There are still some points of the estuary (those located in the surroundings of the Gobela and Galindo tributaries), however, where concentrations of As, Cd, Cu, Pb and Zn are significantly higher than the background values estimated for the area. According to the mean Effects Range Median quotients (mERMqs) calculated for these sites, sediments may still pose a toxicological threat to living organisms. Metal content in inner estuary sediment is low. Specific point sources of metals to the estuary, together with background contamination of diffuse origin, are probably responsible for this situation.

  19. Drought and flood effects on macrobenthic communities in the estuary of Australia's largest river system

    Science.gov (United States)

    Dittmann, Sabine; Baring, Ryan; Baggalley, Stephanie; Cantin, Agnes; Earl, Jason; Gannon, Ruan; Keuning, Justine; Mayo, Angela; Navong, Nathavong; Nelson, Matt; Noble, Warwick; Ramsdale, Tanith

    2015-11-01

    Estuaries are prone to drought and flood events, which can vary in frequency and intensity depending on water management and climate change. We investigated effects of two different drought and flow situations, including a four year long drought (referred to as Millennium drought) and a major flood event, on the macrobenthic community in the estuary and coastal lagoon of the Murray Mouth and Coorong, where freshwater inflows are strictly regulated. The analysis is based on ten years of annual monitoring of benthic communities and environmental conditions in sediment and water. The objectives were to identify changes in diversity, abundance, biomass and distribution, as well as community shifts and environmental drivers for the respective responses. The Millennium drought led to decreased taxonomic richness, abundance and biomass of macrobenthos as hypersaline conditions developed and water levels dropped. More taxa were found under very high salinities than predicted from the Remane diagram. When a flood event broke the Millennium drought, recovery took longer than from a shorter drought followed by small flows. A flow index was developed to assess the biological response subject to the duration of the preceding drought and flow volumes. The index showed higher taxonomic richness, abundance and biomass at intermediate and more continuous flow conditions. Abundance increased quickly after flows were restored, but the benthic community was initially composed of small bodied organisms and biomass increased only after several years once larger organisms became more abundant. Individual densities and constancy of distribution dropped during the drought for almost all macrobenthic taxa, but recoveries after the flood were taxon specific. Distinct benthic communities were detected over time before and after the drought and flood events, and spatially, as the benthic community in the hypersaline Coorong was split off with a salinity threshold of 64 identified by LINKTREE

  20. Water quality in the Elwha River estuary, Washington, from 2006 to 2014.

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This portion of the data release presents water column dissolved nutrient concentration data and water quality parameters from samples collected in the Elwha River...

  1. Behaviour of boron, calcium and magnesium in Mindola river estuary (Gujarat)

    Digital Repository Service at National Institute of Oceanography (India)

    Narvekar, P.V.; Zingde, M.D.; Dalal, V.N.K.

    percentage of removal of B at low chlorinities indicated its rapid removal in the initial encounter of river water with seawater. On the contrary, Ca was preferentially added at low chlorinities. Addition decreased as the chlorinity increased and removal...

  2. Sources of suspended-sediment loads in the lower Nueces River watershed, downstream from Lake Corpus Christi to the Nueces Estuary, south Texas, 1958–2010

    Science.gov (United States)

    Ockerman, Darwin J.; Heitmuller, Franklin T.; Wehmeyer, Loren L.

    2013-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Army Corps of Engineers, Fort Worth District; City of Corpus Christi; Guadalupe-Blanco River Authority; San Antonio River Authority; and San Antonio Water System, developed, calibrated, and tested a Hydrological Simulation Program-FORTRAN (HSPF) watershed model to simulate streamflow and suspended-sediment concentrations and loads during 1958-2010 in the lower Nueces River watershed, downstream from Lake Corpus Christi to the Nueces Estuary in south Texas. Data available to simulate suspended-sediment concentrations and loads consisted of historical sediment data collected during 1942-82 in the study area and suspended-sediment concentration data collected periodically by the USGS during 2006-7 and 2010 at three USGS streamflow-gaging stations (08211000 Nueces River near Mathis, Tex. [the Mathis gage], 08211200 Nueces River at Bluntzer, Tex. [the Bluntzer gage], and 08211500 Nueces River at Calallen, Tex. [the Calallen gage]), and at one ungaged location on a Nueces River tributary (USGS station 08211050 Bayou Creek at Farm Road 666 near Mathis, Tex.). The Mathis gage is downstream from Wesley E. Seale Dam, which was completed in 1958 to impound Lake Corpus Christi. Suspended-sediment data collected before and after completion of Wesley E. Seale Dam provide insights to the effects of the dam and reservoir on suspended-sediment loads transported by the lower Nueces River downstream from the dam to the Nueces Estuary. Annual suspended-sediment loads at the Nueces River near the Mathis, Tex., gage were considerably lower for a given annual mean discharge after the dam was completed than before the dam was completed.

  3. Temporal variations and bioaccumulation of heavy metals in different Suaeda salsa marshes of the Yellow River estuary, China.

    Science.gov (United States)

    Song, Hongli; Sun, Zhigao

    2014-12-01

    To understand the temporal variations and bioaccumulation of heavy metals in the coastal marshes, the concentrations of heavy metals (Cr, Ni, Pb, and Cu) in the two Suaeda salsa marshes [middle S. salsa marsh (MM) and low S. salsa marsh (LM)] of the Yellow River estuary were determined from May to November in 2008 by in situ sampling and inductively coupled plasma mass spectrometry (ICP-MS) analysis. Results showed that heavy metal concentrations in S. salsa of MM and LM were generally in the order of Cu > Cr > Pb > Ni, while those in sediments fell in the order of Cr > Ni > Cu > Pb. Heavy metal concentrations of S. salsa in MM and LM were different, and significant differences were observed in stems (F = 4.797, p = 0.046) and litters (F = 6.799, p = 0.026) for Ni. Litter was the main stock of heavy metals, and the allocations of Cr, Ni, and Pb reached 31.25-51.31, 28.49-42.58, and 29.55-66.79 % (in MM) and 36.73-48.60, 41.70-57.87, and 33.30-60.64 % (in LM), respectively. The ratios of roots/leaves (R/L) and roots/stems (R/S) for Cr and Ni in MM were mostly greater than 1, while those ratios in LM were mostly less than 1, indicating that Cr and Ni in S. salsa at LM had greater mobility compared with those at MM. Moreover, the [accumulation factor, AF]plant of Cr, Ni, Cu, and Pb in LM, especially [AF]root and [AF]stem of Cr and [AF]litter of Ni, was also higher than that in MM. These indicated that S. salsa grown in LM was more suitable for potential biomonitor or phytoremediation of Cr, Ni, Cu, and Pb if intertidal sediments were seriously contaminated with an increase of pollutant loading (especially heavy metals) in the Yellow River estuary. The use of biomonitor (S. salsa) living and growing in LM could yield valuable information not only on the presence of anthropogenic stressors, but, more importantly, on the adverse influence the stressors are having on the environment.

  4. Salinity adaptation of the invasive New Zealand mud snail (Potamopyrgus antipodarum) in the Columbia River estuary (Pacific Northwest, USA): Physiological and molecular studies

    Science.gov (United States)

    Hoy, Marshal; Boese, Bruce L.; Taylor, Louise; Reusser, Deborah; Rodriguez, Rusty

    2012-01-01

    In this study, we examine salinity stress tolerances of two populations of the invasive species New Zealand mud snail Potamopyrgus antipodarum, one population from a high salinity environment in the Columbia River estuary and the other from a fresh water lake. In 1996, New Zealand mud snails were discovered in the tidal reaches of the Columbia River estuary that is routinely exposed to salinity at near full seawater concentrations. In contrast, in their native habitat and throughout its spread in the western US, New Zealand mud snails are found only in fresh water ecosystems. Our aim was to determine whether the Columbia River snails have become salt water adapted. Using a modification of the standard amphipod sediment toxicity test, salinity tolerance was tested using a range of concentrations up to undiluted seawater, and the snails were sampled for mortality at daily time points. Our results show that the Columbia River snails were more tolerant of acute salinity stress with the LC50 values averaging 38 and 22 Practical Salinity Units for the Columbia River and freshwater snails, respectively. DNA sequence analysis and morphological comparisons of individuals representing each population indicate that they were all P. antipodarum. These results suggest that this species is salt water adaptable and in addition, this investigation helps elucidate the potential of this aquatic invasive organism to adapt to adverse environmental conditions.

  5. Isotopic composition of dissolved boron and its geochemical behavior in a freshwater-seawater mixture at the estuary of the Changjiang (Yangtze) River

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The isotopic composition of dissolved boron, in combination with the elemental concentrations of B, Cl and salinities in freshwater-seawater mixed samples taken from the estuary of the Changjiang River, the largest one in China, was investigated in detail in this study. Brackish water and seawater samples from the estuary of the Changjiang River were collected during low water season in November, 1998. Boron isotopic compositions were determined by the Cs2BO2+-graphite technique with a analytical uncertainty of 0.2‰ for NIST SRM 951 and an average analytical uncertainty of 0.8‰ for the samples. The isotopic compositions of boron, expressed in δ11B, and boron concentrations in the Changjiang River at Nanjing and seawater from the open marine East Sea, China, are characterized by δ11B values of -5.4‰ and 40.0‰, as well as 0.0272 and 4.43 mg B/L, respectively. Well-defined correlations between δ11B values, B concentrations and Cl concentrations are interpreted in terms of binary mixing between river input water and East Sea seawater by a process of straightforward dilution. The offsets of δ11B values are not related to the contents of clastic sediment and to the addition of boron. These relationships favor a conservative behavior of boron at the estuarine of the Changjiang River.

  6. Hydrologic habitat preferences of select southeastern USA fishes resilient to river ecosystem fragmentation

    Science.gov (United States)

    Andrew L. Rypel; David R. Bayne

    2009-01-01

    Large-scale habitat preferences of riverine taxa are not always revealed by examining community data. Here, we show how lipid and growth can be used to evaluate hydrologic habitat preferences of fishes resilient to river fragmentation (i.e. species that can tolerate river fragmentation by dams, but not collapse). Lipid content was examined for seven fishes in a major...

  7. Columbia River Estuary Hybrid Model Studies. Report 1. Verification of Hybrid Modeling of the Columbia River Mouth.

    Science.gov (United States)

    1983-09-01

    King, J.M., and Carlson, P.R. 1966. " Seismic Reflection Studies of Buried Channels off the Columbia River," Ore Bin, Vol. 28, Aug. 12. Boone, C.G...Adjacent Ocean Waters, University of Washington Press, Seattle, WA. 64. Foster, R.F. 1972. The History of Hanford and Its Contribution of Radionuclides...Corvallis, OR. 81. Hanson, P.J., and Forster, W.O. 1969. "Measurement of Columbia River Flow Time from Hanford Reactors to Astoria, Oregon - Summer

  8. Impact of human activities on subaqueous topographic change in Lingding Bay of the Pearl River estuary, China, during 1955–2013

    Science.gov (United States)

    Wu, Z. Y.; Saito, Yoshiki; Zhao, D. N.; Zhou, J. Q.; Cao, Z. Y.; Li, S. J.; Shang, J. H.; Liang, Y. Y.

    2016-11-01

    Estuaries have been sites of intensive human activities during the past century. Tracing the evolution of subaqueous topography in estuaries on a decadal timescale enables us to understand the effects of human activities on estuaries. Bathymetric data from 1955 to 2010 show that land reclamation decreased the subaqueous area of Lingding Bay, in the Pearl River estuary, by ~170 km2 and decreased its water volume by 615 × 106 m3, representing a net decrease of 11.2 × 106 m3 per year and indicating the deposition of approximately 14.5 Mt/yr of sediment in Lingding Bay during that period. Whereas Lingding Bay was mainly governed by natural processes with slight net deposition before 1980, subsequent dredging and large port engineering projects changed the subaqueous topography of the bay by shallowing its shoals and deepening its troughs. Between 2012 and 2013, continuous dredging and a surge of sand excavation resulted in local changes in water depth of ± 5 m/yr, far exceeding the magnitude of natural topographic evolution in Lingding Bay. Reclamation, dredging, and navigation-channel projects removed 8.4 Mt/yr of sediment from Lingding Bay, representing 29% of the sediment input to the bay, and these activities have increased recently.

  9. Tidal wetlands of the Yaquina and Alsea River estuaries, Oregon: Geographic Information Systems layer development and recommendations for National Wetlands Inventory revisions

    Science.gov (United States)

    Brophy, Laura S.; Reusser, Deborah A.; Janousek, Christopher N.

    2013-01-01

    Geographic Information Systems (GIS) layers of current, and likely former, tidal wetlands in two Oregon estuaries were generated by enhancing the 2010 National Wetlands Inventory (NWI) data with expert local field knowledge, Light Detection and Ranging-derived elevations, and 2009 aerial orthophotographs. Data were generated for two purposes: First, to enhance the NWI by recommending revised Cowardin classifications for certain NWI wetlands within the study area; and second, to generate GIS data for the 1999 Yaquina and Alsea River Basins Estuarine Wetland Site Prioritization study. Two sets of GIS products were generated: (1) enhanced NWI shapefiles; and (2) shapefiles of prioritization sites. The enhanced NWI shapefiles contain recommended changes to the Cowardin classification (system, subsystem, class, and/or modifiers) for 286 NWI polygons in the Yaquina estuary (1,133 acres) and 83 NWI polygons in the Alsea estuary (322 acres). These enhanced NWI shapefiles also identify likely former tidal wetlands that are classified as upland in the current NWI (64 NWI polygons totaling 441 acres in the Yaquina estuary; 16 NWI polygons totaling 51 acres in the Alsea estuary). The former tidal wetlands were identified to assist strategic planning for tidal wetland restoration. Cowardin classifications for the former tidal wetlands were not provided, because their current hydrology is complex owing to dikes, tide gates, and drainage ditches. The scope of this project did not include the field evaluation that would be needed to determine whether the former tidal wetlands are currently wetlands, and if so, determine their correct Cowardin classification. The prioritization site shapefiles contain 49 prioritization sites totaling 2,177 acres in the Yaquina estuary, and 39 prioritization sites totaling 1,045 acres in the Alsea estuary. The prioritization sites include current and former (for example, diked) tidal wetlands, and provide landscape units appropriate for basin

  10. Investigating the Impacts of Landuse-landcover (LULC Change in the Pearl River Delta Region on Water Quality in the Pearl River Estuary and Hong Kong’s Coast

    Directory of Open Access Journals (Sweden)

    Hongyan Xi

    2009-11-01

    Full Text Available Water quality information in the coastal region of Hong Kong and the Pearl River Estuary (PRE is of great concern to the local community. Due to great landuse-landcover (LULC changes with rapid industrialization and urbanization in the Pearl River Delta (PRD region, water quality in the PRE has worsened during the last 20 years. Frequent red tide and harmful algal blooms have occurred in the estuary and its adjacent coastal waters since the 1980s and have caused important economic losses, also possibly threatening to the coastal environment, fishery, and public health in Hong Kong. In addition, recent literature shows that water nutrients in Victoria Harbor of Hong Kong have been proven to be strongly influenced by both the Pearl River and sewage effluent in the wet season (May to September, but it is still unclear how the PRE diluted water intrudes into Victoria Harbor. Due to the cloudy and rainy conditions in the wet season in Hong Kong, ASAR images will be used to monitor the PRE river plumes and track the intruding routes of PRE water nutrients. In this paper, we first review LULC change in the PRD and then show our preliminary results to analyze water quality spatial and temporal information from remote observations with different sensors in the coastal region and estuary. The study will also emphasizes on time series of analysis of LULC trends related to annual sediment yields and critical source areas of erosion for the PRD region since the 1980s.

  11. Fate of mercury species in the coastal plume of the Adour River estuary (Bay of Biscay, SW France)

    Energy Technology Data Exchange (ETDEWEB)

    Sharif, Abubaker; Monperrus, Mathilde; Tessier, Emmanuel; Bouchet, Sylvain; Pinaly, Hervé; Rodriguez-Gonzalez, Pablo [Laboratoire de Chimie Analytique Bio-Inorganique et Environnement, Institut Pluridisciplinaire de Recherche sur l' Environnement et les Matériaux, UMR 5254 CNRS, Université de Pau et des Pays de l' Adour, Hélioparc Pau Pyrénées, 2 av. P. Angot, 64053 Pau cedex 9 (France); Maron, Philippe [Laboratoire des Sciences de l' Ingénieur Appliquées à la Mécanique et au Génie Electrique, Institut Supérieur Aquitain du Bâtiment et des Travaux Publics, Université de Pau et des Pays de l' Adour, Allée du Parc Montaury, 64600 Anglet (France); Amouroux, David, E-mail: david.amouroux@univ-pau.fr [Laboratoire de Chimie Analytique Bio-Inorganique et Environnement, Institut Pluridisciplinaire de Recherche sur l' Environnement et les Matériaux, UMR 5254 CNRS, Université de Pau et des Pays de l' Adour, Hélioparc Pau Pyrénées, 2 av. P. Angot, 64053 Pau cedex 9 (France)

    2014-10-15

    Because mercury (Hg) undergoes significant biogeochemical processes along the estuarine-coastal continuum, the objective of this work was to investigate the distribution and reactivity of methylmercury (MeHg), inorganic mercury (Hg(II)) and gaseous Hg (DGM) in plume waters of the Adour River estuary (Bay of Biscay). Vertical profiles, spatial and tidal variability of Hg species concentrations were evaluated during two campaigns (April 2007 and May 2010) characterized by significant plume extents over the coastal zone. Incubations with isotopically enriched tracers were performed on bulk and filtered waters under sunlight or dark conditions to investigate processes involved in Hg methylation, demethylation and reduction rates. Total Hg(II) concentrations were more dispersed in April 2007 (5.2 ± 4.9 pM) than in May 2010 (2.5 ± 1.1 pM) while total MeHg concentrations were similar for both seasons and averaged 0.13 ± 0.07 and 0.18 ± 0.11 pM, respectively. DGM concentrations were also similar between the two campaigns, averaging 0.26 ± 0.10 and 0.20 ± 0.09 pM, respectively. Methylation yields remained low within the estuarine plume (< 0.01–0.4% day{sup −1}) while MeHg was efficiently demethylated via both biotic and abiotic pathways (2.3–55.3% day{sup −1}), mainly photo-induced. Hg reduction was also effective in these waters (0.3–43.5% day{sup −1}) and was occurring in both light and dark conditions. The results suggest that the plume is overall a sink for MeHg with integrated net demethylation rates, ranging from 2.0–3.7 g (Hg) d{sup −1}, in the same range than the estimated MeHg inputs from the estuary (respectively, 0.9 and 3.5 g (Hg) d{sup −1}). The large evasion of DGM from the plume waters to the atmosphere (8.8–26.9 g (Hg) d{sup −1}) may also limit Hg{sub T} inputs to coastal waters (33–69 g (Hg) d{sup −1}). These processes are thus considered to be most significant in controlling the fate of Hg transferred from the river to the

  12. Occurrence of Cymbasoma longispinosum Bourne, 1890 (Copepoda: Monstrilloida in the Curuçá River estuary (Amazon Littoral

    Directory of Open Access Journals (Sweden)

    Natália R. Leite

    2010-09-01

    Full Text Available 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.O presente trabalho foi desenvolvido para verificar a ocorrência e distribuição de Cymbasoma longispinosum Bourne, 1890 em um estuário tropical amazônico da região norte do Brasil. As coletas foram realizadas bimestralmente de julho/2003 a julho/2004 em dois diferentes transectos (rios Muriá e Curuçá situados ao longo do estuário do Curuçá (Pará, Norte do Brasil. Amostras foram coletadas durante marés de quadratura por intermédio de arrastos com redes de plâncton de 200μm de abertura de malha, através de um pequeno barco a motor (1 a 1,5 knots. Amostras adicionais de água subsuperficial foram coletadas para determinação dos parâmetros ambientais. Machos e fêmeas de C. longispinosum foram observados apenas durante os meses de

  13. Contribution of priority PAHs and POPs to Ah receptor-mediated activities in sediment samples from the River Elbe Estuary, Germany.

    Directory of Open Access Journals (Sweden)

    Jens C Otte

    Full Text Available The estuary of the River Elbe between Hamburg and the North Sea (Germany is a sink for contaminated sediment and suspended particulate matter (SPM. One major concern is the effect of human activities on the hydrodynamics, particularly the intensive dredging activities in this area that may result in remobilization of sediment-bound pollutants. The aim of this study was to identify pollutants contributing to the toxicological risk associated with re-suspension of sediments in the Elbe Estuary by use of an effect-directed analysis that combines chemical and biological analyses in with specific fractionation techniques. Sediments were collected from sites along the Elbe Estuary and a site from a small harbor basin of the Elbe Estuary that is known to be polluted. The sixteen priority EPA-PAHs were quantified in organic extracts of sediments. In addition, dioxin equivalents of sediments were investigated by use of the 7-ethoxyresorufin O-deethylase assay with RTL-W1 cells and the Ah receptor-mediated luciferase transactivation assay with H4IIE-luc cells. Quantification of the 16 priority PAHs revealed that sediments were moderately contaminated at all of the sites in the Elbe River Estuary (<0.02-0.906 µg/g dw. Sediments contained relatively small concentrations of dioxin equivalents (Bio-TEQ with concentrations ranging from 15.5 to 322 pg/g dw, which were significantly correlated with dioxin equivalents calculated based on toxicity reference values and concentrations of PAH. The concentration of Bio-TEQ at the reference site exceeded 200,000 pg/g dw. In a potency balance the 16 PAHs explained between 47 and 118% of the Bio-TEQ in the luciferase assay, which can be explained by the constant input of PAHs bound to SPM from the upper course of the Elbe River into its estuary. Successful identification of a significant portion of dioxin-like activity to priority PAHs in complex environmental samples such as sediments has rarely been reported.

  14. Contribution of Priority PAHs and POPs to Ah Receptor-Mediated Activities in Sediment Samples from the River Elbe Estuary, Germany

    Science.gov (United States)

    Otte, Jens C.; Keiter, Steffen; Faßbender, Christopher; Higley, Eric B.; Rocha, Paula Suares; Brinkmann, Markus; Wahrendorf, Dierk-Steffen; Manz, Werner; Wetzel, Markus A.; Braunbeck, Thomas; Giesy, John P.; Hecker, Markus; Hollert, Henner

    2013-01-01

    The estuary of the River Elbe between Hamburg and the North Sea (Germany) is a sink for contaminated sediment and suspended particulate matter (SPM). One major concern is the effect of human activities on the hydrodynamics, particularly the intensive dredging activities in this area that may result in remobilization of sediment-bound pollutants. The aim of this study was to identify pollutants contributing to the toxicological risk associated with re-suspension of sediments in the Elbe Estuary by use of an effect-directed analysis that combines chemical and biological analyses in with specific fractionation techniques. Sediments were collected from sites along the Elbe Estuary and a site from a small harbor basin of the Elbe Estuary that is known to be polluted. The sixteen priority EPA-PAHs were quantified in organic extracts of sediments. In addition, dioxin equivalents of sediments were investigated by use of the 7-ethoxyresorufin O-deethylase assay with RTL-W1 cells and the Ah receptor-mediated luciferase transactivation assay with H4IIE-luc cells. Quantification of the 16 priority PAHs revealed that sediments were moderately contaminated at all of the sites in the Elbe River Estuary (<0.02–0.906 µg/g dw). Sediments contained relatively small concentrations of dioxin equivalents (Bio-TEQ) with concentrations ranging from 15.5 to 322 pg/g dw, which were significantly correlated with dioxin equivalents calculated based on toxicity reference values and concentrations of PAH. The concentration of Bio-TEQ at the reference site exceeded 200,000 pg/g dw. In a potency balance the 16 PAHs explained between 47 and 118% of the Bio-TEQ in the luciferase assay, which can be explained by the constant input of PAHs bound to SPM from the upper course of the Elbe River into its estuary. Successful identification of a significant portion of dioxin-like activity to priority PAHs in complex environmental samples such as sediments has rarely been reported. PMID:24146763

  15. The source of natural and anthropogenic heavy metals in the sediments of the Minjiang River Estuary (SE China): Implications for historical pollution

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Yonghang, E-mail: yonghang_xu@163.com [Open Laboratory of Ocean and Coast Environmental Geology, Third Institute of Oceanography State Oceanic Administration, 178 Daxue Road, Xiamen 361005 (China); Sun, Qinqin [Fujian Provincial Key Laboratory of Coast and Island Management Technology Study, Fujian Institute of Oceanography, Xiamen 361013 (China); Yi, Liang [State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029 (China); Yin, Xijie; Wang, Aijun; Li, Yunhai; Chen, Jian [Open Laboratory of Ocean and Coast Environmental Geology, Third Institute of Oceanography State Oceanic Administration, 178 Daxue Road, Xiamen 361005 (China)

    2014-09-15

    Two sedimentary cores in the Minjiang River estuary (SE China) are documented for grain size, clay minerals, heavy metals, magnetic parameters and Pb isotopes to investigate the source and historical variation of heavy metals. The MJK9 core was collected outside of the Minjiang River estuary, and the core is composed of mixed sediments, of which ∼ 70% from the Yangtze River and 30% from the Minjiang River. It is thus difficult to be used for tracing the human activity along the Minjiang River. In contrast, the sediments of MJK16 core which was collected in a nearshore area are primarily from the Minjiang River. The enrichment factors of the sediments were < 1.5, indicating minor pollution. The results indicate that the sediments of the MJK16 core have Cu and Pb concentrations increasing since 1980, associated with the increase of magnetic mineral concentration and {sup 206}Pb/{sup 207}Pb and {sup 206}Pb/{sup 208}Pb of the sediments. We compared the Pb isotopic compositions between our results and those for the deposit mining in the Minjiang River basin, and aerosols and coal dust in south China, and considered that Pb in the sediments of the MJK16 core was derived primarily from weathered rocks as well as industrial emission (e.g. coal combustion). The sediments have anthropogenic Pb concentrations ranging from 6% in 1950 to 23.7% in 2010, consistent with the impact of rapid urban and industrial development in China. - Highlights: • Grain size, clay mineral and Pb isotope were used to identify sediment sources. • The contribution of Yangtze River to northern of Taiwan Strait was quantified. • Enrichment factors indicated Cu and Pb have increased over the last decades. • Coal combustion was the prevailing contamination source. • The anthropogenic Pb concentrations ranged from 6% in 1950 to 23.7% in 2010.

  16. Quantification of annual sediment deposits for sustainable sand management in Aghanashini river estuary.

    Science.gov (United States)

    Ramachandra, T V; Vinay, S; Subash Chandran, M D

    2017-08-11

    Sedimentation involving the process of silt transport also carries nutrients from upstream to downstream of a river/stream. Sand being one of the important fraction of these sediments is extracted in order to cater infrastructural/housing needs in the region. This communication is based on field research in the Aghanshini river basin, west coast of India. Silt yield in the river basin and the sedimentation rate assessed using empirical techniques supplemented with field quantifications using soundings (SONAR), show the sediment yield of 1105-1367 kilo cum per year and deposition of sediment of 61 (2016) to 71 (2015) cm. Quantifications of extractions at five locations, reveal of over exploitation of sand to an extent of 30% with damages to the breeding ground of fishes, reduced productivity of bivalves, etc., which has affected dependent people's livelihood. This study provides vital insights towards sustainable sand harvesting through stringent management practices. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Macrobenthic assemblages of the Changjiang River estuary (Yangtze River, China) and adjacent continental shelf relative to mild summer hypoxia

    Science.gov (United States)

    Liao, Yibo; Shou, Lu; Tang, Yanbin; Zeng, Jiangning; Gao, Aigen; Chen, Quanzhen; Yan, Xiaojun

    2017-05-01

    To assess the effects of hypoxia, macrobenthic communities along an estuarine gradient of the Changjiang estuary and adjacent continental shelf were analyzed. This revealed spatial variations in the communities and relationships with environmental variables during periods of reduced dissolved oxygen (DO) concentration in summer. Statistical analyses revealed significant differences in macrobenthic community composition among the three zones: estuarine zone (EZ), mildly hypoxic zone (MHZ) in the continental shelf, and normoxic zone (NZ) in the continental shelf (Global R =0.206, P =0.002). Pairwise tests showed that the macrobenthic community composition of the EZ was significantly different from the MHZ (pairwise test R =0.305, P =0.001) and the NZ (pairwise test R =0.259, P =0.001). There was no significant difference in macrobenthic communities between the MHZ and the NZ (pairwise test R =0.062, P =0.114). The taxa included small and typically opportunistic polychaetes, which made the greatest contribution to the dissimilarity between the zones. The effects of mild hypoxia on the macrobenthic communities are a result not only of reduced DO concentration but also of differences in environmental variables such as temperature, salinity, and nutrient concentrations caused by stratification.

  18. The influence of a river plume on the sea-ice meiofauna in south-eastern Hudson Bay

    Science.gov (United States)

    Grainger, E. H.

    1988-08-01

    Outflow from the Great Whale River produces a substantial freshwater layer (plume) beneath the winter ice cover and above water of higher salinity in south-eastern Hudson Bay. In 1983, samples of the lower-ice fauna and of zooplankton beneath the ice, were taken within, below and beyond the offshore reach of the plume. Nematodes accounted for the highest numbers (mean of 1956 1 1in the lower 3 cm of ice), and copepods, mainly Harpacticus and Halectinosoma with fewer Tisbe and Oithona, for the greatest biomass. All ice-inhabiting taxa were also found in the water below the ice, but many zooplankters occurring immediately beneath the ice did not form part of the ice fauna. No major qualitative differences were evident between the ice communities existing above the plume and offshore from it, but quantitative distinctions were readily apparent. Animals were consistently more concentrated (by 2-3 orders of magnitude) in the lower 3 cm of the ice than in the water immediately below, both over the plume and outside it. Except for the dominant rotifers in the plume, the concentration of zooplankton there was only 10% of that found in the surface water outside the plume. The river plume exerts a strong influence over the quantity of the fauna in the sea ice immediately above it. Changes in location and extent of the plume therefore may have an important effect on the food chain based in the sea ice.

  19. Fish gills alterations as potential biomarkers of environmental quality in a eutrophized tropical river in south-eastern Brazil.

    Science.gov (United States)

    Nascimento, A A; Araújo, F G; Gomes, I D; Mendes, R M M; Sales, A

    2012-06-01

    Gill anomalies in three common fish species of different taxonomic order, habitat dwelling and feeding habits (one Characiformes, Oligosarcus hepsetus; one Siluriformes, Hypostomus auroguttatus; and one Perciformes, Geophagus brasiliensis) from a eutrophized tropical river in south-eastern in Brazil were compared. The aim of this study was to search for sentinel species that could be used as potential biomarkers of environmental quality. Most fish had gills with histological changes, namely epithelial lifting, interstitial oedema, leucocyte infiltration, hyperplasia of the epithelial cells, lamellar fusion, vasodilatation and necrosis. On the other hand, lamellar blood congestion and lamellar aneurysm, which are more serious and often irreversible changes, were recorded for the water column carnivorous O. hepsetus and, to a lesser extent, for the bottom-dwelling detritivorous H. auroguttatus. A histopathological alteration index (HAI) based on the occurrence and severity of gills anomalies indicated that O. hepsetus (mean score = 11.4) had significantly higher values (Kruskall-Wallis H(2,41) = 15.95, P = 0.0003) compared with G. brasiliensis (mean score = 7.0). Overall, the omnivorous G. brasiliensis had comparatively lesser occurrence of most gill anomalies compared with other two species, being less suitable as biomarker of environmental quality. In contrast, the water column-dweller O. hepsetus (water column) and the bottom-dweller H. auroguttatus had gills most susceptible to changes, making them more suitable for using as histological biomarkers of the environmental quality in entrophized tropical rivers.

  20. Potential submarine geologic hazards at the entrance of the Pearl River Estuary in the northern South China Sea

    Science.gov (United States)

    Zhang, Zhiqiang; Wei, Zhiqiang; He, Huizhong; Wei, Wei; Qian, Libing; Li, Tuanjie

    2016-08-01

    The potential submarine geologic hazards were distinguished and categorized at the entrance of the Pearl River Estuary in the northern South China Sea, based upon the analysis of side scan sonar and sub-bottom profiler surveying data of about 2500 km long, in an area about 2000 km2 around the Wanshan Archipelago. The data obtained in the survey has the highest spatial resolution by far, which could reveal more detailed distributions and characteristics of the geologic hazards than before. In the study region, three paleo-channels that were buried about 10-30 m below the seabed were found; more than 10 shallow gas areas were discovered. The sand waves found in the region were generally small and located near the islands, and twenty pockmarks found on the seabed were mostly concentrated to north of Zhuzhou island. There are also many man-made obstacles in the region, such as wreckages, pipeline, etc. In this paper we provide a detailed distribution map of the submarine geologic hazards in this region for the first time, and discuss their formation and harmfulness, which will provide a scientific basis for marine engineering construction, marine geologic disaster prevention and mitigation.

  1. Proceedings of the Columbia River Estuary Conference on Ecosystem Restoration, April 29-30, 2008, Astoria, Oregon.

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Gary E. [Pacific Northwest National Laboratory; Sutherland, G. Bruce [Oregon Department of Environmental Quality (retired)

    2008-09-29

    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. A compact disk, attached to the back cover, contains material in hypertext-markup-language from the conference website (http://cerc.labworks.org/) and the individual presentations.

  2. Potential effect of sedimentary iron-phosphorus accumulation on frequent algal bloom in the Pearl River Estuary

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Based on laboratory culture of harmful alga on iron and phosphorus uptake, and the study of accu-mulation of iron-phosphorus in cores and release of iron and phosphorus from surficial sediments collected in the Pearl River Estuary, the reasons of the high frequency of phytoplankton bloom therein are discussed. The results show that Fe starvation can make algal growth rate slow down and the peak of cell number decrease. Fe and P contents in algal cell bear a significant correlation and the molar ratio of P:Fe is ~356:1, suggesting that algal uptake of Fe and P is synergistic. Total Fe and total P in sediments are positively correlated and Fe-P is the main species of inorganic sedimentary P. Through continuous leaching with agitation, 34.26%―80.21% of exchangeable P and 4.04%―22.52% of ex-changeable Fe are released from surficial sediments, implying that the accumulation of Fe-P in sedi-ments is available for providing nutrients (P and essential Fe) for the demand of phytoplankton bloom. These factors might be responsible for a higher frequency of red tides than other marine regions.

  3. Parasites in the mangrove oyster Crassostrea rhizophorae cultivated in the estuary of the Graciosa River in Taperoá, Bahia.

    Science.gov (United States)

    Cova, Aliane Watanabe; Serafim Júnior, Moacyr; Boehs, Guisla; Souza, Jackson Moreira de

    2015-01-01

    In this work, parasites associated with the mangrove oyster Crassostrea rhizophorae were studied at a cultivation unit in the estuary of the Graciosa River in Taperoá, Bahia. On a monthly basis, between April 2011 and March 2012, 20 oysters were collected, measured and fixed in 10% formaldehyde. In order to identify the parasites, routine histological techniques were used. The specimens were embedded in paraffin and sections, 7 µm thick, were cut. These were then stained with Harris hematoxylin and eosin and were examined using an optical microscope. The parameters analyzed to investigate water quality showed that the temperature ranged from 23.9 °C to 29.3 °C, water salinity from 0.4 to 24.2 Practical Salinity Units PSU and recorded rainfall from 80 mm to 406.4 mm/month. During the parasitological analyses, infestation of the polychaete Neanthes succinea was observed in 41% of the oysters. Through histological techniques, the following parasites were identified: colonies of Rickettsia-like organisms (RLOs); the protozoa Nematopsis sp. and Ancistrocoma sp.; the turbellarian Urastoma sp.; the metacestode Tylocephalum sp. and an unidentified tapeworm. The data collected showed that there was low-intensity infection with and prevalence of parasites, except for Nematopsis sp., thus attesting that these cultivated oysters were in a healthy condition.

  4. First record of parasitism in the mangrove oyster Crassostrea rhizophorae (Bivalvia: Ostreidae at Jaguaribe River estuary - Ceará, Brazil

    Directory of Open Access Journals (Sweden)

    RC Sabry

    Full Text Available Mangrove oysters Crassostrea rhizophorae were sampled monthly in the estuary of Jaguaribe River, on the east coast of Ceará State, Brazil, between August, 2000 and December, 2001, making up 170 individuals. The water temperature varied from 26 to 30 °C and salinity from 21 to 42‰. The animals' size ranged from 3.4 to 7.2 cm height. Macroscopical and histopathological analyses were carried out in the oysters' tissues. The histological exams showed protozoans and metazoans of genera Nematopsis and Tylocephalum, respectively. Nematopsis prevalence varied from 60 to 100% and it was higher in the gills and mantle. The oocysts presented a mean size of 11.5 µm (±1.32 length and 9.1 µm (±1.06 width (n = 30, up to 3 oocysts/phagocyte having been observed. Several animals presented focal hemocitical reaction. The percentage of Tylocephalum was 1.7%. In spite of the high infection prevalence by Nematopsis, infected animals did not have their reproductive cycle impaired.

  5. Parasites in the mangrove oyster Crassostrea rhizophorae cultivated in the estuary of the Graciosa River in Taperoá, Bahia

    Directory of Open Access Journals (Sweden)

    Aliane Watanabe Cova

    Full Text Available In this work, parasites associated with the mangrove oyster Crassostrea rhizophorae were studied at a cultivation unit in the estuary of the Graciosa River in Taperoá, Bahia. On a monthly basis, between April 2011 and March 2012, 20 oysters were collected, measured and fixed in 10% formaldehyde. In order to identify the parasites, routine histological techniques were used. The specimens were embedded in paraffin and sections, 7 µm thick, were cut. These were then stained with Harris hematoxylin and eosin and were examined using an optical microscope. The parameters analyzed to investigate water quality showed that the temperature ranged from 23.9 °C to 29.3 °C, water salinity from 0.4 to 24.2 Practical Salinity Units PSU and recorded rainfall from 80 mm to 406.4 mm/month. During the parasitological analyses, infestation of the polychaete Neanthes succinea was observed in 41% of the oysters. Through histological techniques, the following parasites were identified: colonies of Rickettsia-like organisms (RLOs; the protozoa Nematopsis sp. and Ancistrocoma sp.; the turbellarian Urastoma sp.; the metacestode Tylocephalum sp. and an unidentified tapeworm. The data collected showed that there was low-intensity infection with and prevalence of parasites, except for Nematopsis sp., thus attesting that these cultivated oysters were in a healthy condition.

  6. First record of parasitism in the mangrove oyster Crassostrea rhizophorae (Bivalvia: Ostreidae) at Jaguaribe River estuary--Ceará, Brazil.

    Science.gov (United States)

    Sabry, R C; Gesteira, T C V; Boehs, G

    2007-11-01

    Mangrove oysters Crassostrea rhizophorae were sampled monthly in the estuary of Jaguaribe River, on the east coast of Ceará State, Brazil, between August, 2000 and December, 2001, making up 170 individuals. The water temperature varied from 26 to 30 degrees C and salinity from 21 to 42. The animals' size ranged from 3.4 to 7.2 cm height. Macroscopical and histopathological analyses were carried out in the oysters' tissues. The histological exams showed protozoans and metazoans of genera Nematopsis and Tylocephalum, respectively. Nematopsis prevalence varied from 60 to 100% and it was higher in the gills and mantle. The oocysts presented a mean size of 11.5 microm (+/-1.32) length and 9.1 microm (+/-1.06) width (n = 30), up to 3 oocysts/phagocyte having been observed. Several animals presented focal hemocitical reaction. The percentage of Tylocephalum was 1.7%. In spite of the high infection prevalence by Nematopsis, infected animals did not have their reproductive cycle impaired.

  7. Spatial and Vertical Distribution of Dechlorane Plus in Mangrove Sediments of the Pearl River Estuary, South China.

    Science.gov (United States)

    Sun, Yu-Xin; Zhang, Zai-Wang; Xu, Xiang-Rong; Hao, Qin-Wei; Hu, Yong-Xia; Zheng, Xiao-Bo; Luo, Xiao-Jun; Diao, Zeng-Hui; Mai, Bi-Xian

    2016-10-01

    Thirty surface sediments and three sediment cores were collected from mangrove wetlands in the Pearl River Estuary of South China to investigate the spatial and vertical distribution of Dechlorane Plus (DP). DP concentrations in the mangrove surface sediments ranged from 0.0130 to 1.504 ng/g dry weight (dw). DP concentrations in sediments from Shenzhen were significantly greater than those from Guangzhou and Zhuhai. Anti-Cl11-DP, the dechlorinated product of anti-DP, was also detected in the mangrove sediments with concentrations ranged from not detected to 0.0198 ng/g dw. Significant positive relationship between anti-Cl11-DP and anti-DP levels was observed in the mangrove sediments, suggesting that photo and/or microbial degradation of anti-DP might occur in the sediments. The f anti values in the mangrove sediments were close to those in the technical DP products, suggesting that stereoselective enrichment of anti-DP may not exist in the mangrove sediments. DP concentrations in the mangrove sediment cores generally showed an increasing trend from the bottom to top layers. This is the first study to report the occurrence of DP and its degradation product in the mangrove wetlands.

  8. Numerical simulation of suspended sediment concentration by 3D coupled wave-current model in the Oujiang River Estuary, China

    Science.gov (United States)

    Xu, Ting; You, Xue-yi

    2017-04-01

    A 3D sediment transport model based on the modified environmental fluid dynamics code (EFDC) and the nearshore waves simulation model (SWAN) is developed to study the change of suspended sediment concentration and bottom shear stress under the actions of pure current and wave-current. After being validated by the field measured data, the proposed sediment transport model is applied in the Oujiang River Estuary, China. The results show that the ratios of both bottom shear stress and suspended sediment concentration of pure current to those of wave-current show a gradually increase from shallow nearshore water to deep open sea. The results also show that the proportion of wave contributions on bottom shear stress and sediment concentration are above 60%, approximately 20-30% and less than 10% for the water depth of less than 5 m, 5-10 m and more than 20 m, respectively. For the waters among islands, the proportion of wave contribution to bottom shear stress and sediment concentration is reduced to 10-20% for -5 m water depth and this is more obvious for the waves of large amplitude. The bottom stress and suspended sediment concentration between islands are mainly controlled by tidal current, and the effect of wave is not significant.

  9. Soil as levels and bioaccumulation in Suaeda salsa and Phragmites australis wetlands of the Yellow River Estuary, China.

    Science.gov (United States)

    Wang, Junjing; Bai, Junhong; Gao, Zhaoqin; Lu, Qiongqiong; Zhao, Qingqing

    2015-01-01

    Little information is available on As contamination dynamics in the soil-plant systems of wetlands. Total arsenic (As) in soil and plant samples from Suaeda salsa and Phragmites australis wetlands was measured in the Yellow River Estuary (YRE) in summer and autumn of 2007 to investigate the seasonal changes in As concentrations in different wetlands. The results showed that soil As levels greatly exceeded the global and regional background values. As levels in soil and the roots and stems of both types of plants were much higher in summer than in autumn, whereas leaf As showed higher level in autumn. Soil sulfur was the main factor influencing As levels in Suaeda salsa wetlands, whereas soil porosity was the most important factor for Phragmites australis wetlands. The contamination factor (CF) showed moderately to considerably polluted levels of As in both wetland soils. Plant roots and leaves of Suaeda salsa had higher As concentrations and biological concentration factors (BCFs) than stems, while the leaves and stems of Phragmites australis showed higher As levels and BCFs than roots. Compared to Phragmites australis, Suaeda salsa generally showed higher translocation factor (TF), while TF values for both plant species were higher in summer than in autumn.

  10. Spatiotemporal Trends of Heavy Metals in Indo-Pacific Humpback Dolphins (Sousa chinensis) from the Western Pearl River Estuary, China.

    Science.gov (United States)

    Gui, Duan; Yu, Ri-Qing; Karczmarski, Leszek; Ding, Yulong; Zhang, Haifei; Sun, Yong; Zhang, Mei; Wu, Yuping

    2017-02-07

    We assessed the spatiotemporal trends of the concentrations of 11 heavy metals (HMs) in the liver and kidney of Indo-Pacific humpback dolphins (Sousa chinensis) from western Pearl River Estuary (PRE) during 2004-2015. The hepatic levels of Cr, As, and Cu in these dolphins were among the highest reported for cetaceans globally, and the levels of Zn, Cu, and Hg were sufficiently high to cause toxicological effects in some of the animals. Between same age-sex groups, dolphins from Lingdingyang were significantly more contaminated with Hg, Se, and V than those from the West-four region, while the opposite was true for Cd. Generalized additive mixed models showed that most metals had significant but dissimilar temporal trends over a 10-year period. The concentrations of Cu and Zn increased significantly in recent years, corresponding to the high input of these metals in the region. Body-length-adjusted Cd levels peaked in 2012, accompanied by the highest annual number of dolphin stranding events. In contrast to the significant decrease in HM levels in the dolphins in Hong Kong waters (the eastern reaches of the PRE), the elevated metal exposure in the western PRE raises serious concerns.

  11. Metabolic and phylogenetic profile of bacterial community in Guishan coastal water (Pearl River Estuary), South China Sea

    Science.gov (United States)

    Hu, Xiaojuan; Liu, Qing; Li, Zhuojia; He, Zhili; Gong, Yingxue; Cao, Yucheng; Yang, Yufeng

    2014-10-01

    Characteristics of a microbial community are important as they indicate the status of aquatic ecosystems. In the present study, the metabolic and phylogenetic profile of the bacterioplankton community in Guishan coastal water (Pearl River Estuary), South China Sea, at 12 sites (S1-S12) were explored by community-level physiological profiling (CLPP) with BIOLOG Eco-plate and denaturing gradient gel electrophoresis (DGGE). Our results showed that the core mariculture area (S6, S7 and S8) and the sites associating with human activity and sewage discharge (S11 and S12) had higher microbial metabolic capability and bacterial community diversity than others (S1-5, S9-10). Especially, the diversity index of S11 and S12 calc