WorldWideScience

Sample records for zhangjiang river estuary

  1. Distribution of polycyclic aromatic hydrocarbons in sediments from Yellow River Estuary and Yangtze River Estuary, China.

    Science.gov (United States)

    Hui, Yamei; Zheng, Minghui; Liu, Zhengtao; Gao, Lirong

    2009-01-01

    Surface sediment samples collected from twenty-one sites of Yellow River Estuary and Yangtze River Estuary were determined for sixteen priority polycyclic aromatic hydrocarbons (PAHs) by isotope dilution GC-MS method. The total PAH contents varied from 10.8 to 252 ng/g in Yellow River Estuary sediment, and from 84.6 to 620 ng/g in Yangtze River Estuary sediment. The mean total PAH content of Yangtze River Estuary was approximately twofold higher than that of Yellow River Estuary. The main reasons for the difference may be the rapid industrial development and high population along Yangtze River and high silt content of Yellow River Estuary. The evaluation of PAH sources suggested that PAHs in two estuaries sediments estuaries were derived primarily from combustion sources, but minor amounts of PAHs were derived from petroleum source in Yellow River Estuary. PAHs may be primary introduced to Yellow River Estuary via dry/wet deposition, wastewater effluents, and accidental oil spills, and Yangtze River Estuary is more prone to be affected by wastewater discharge. PMID:20131590

  2. 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 estuarys contribution to the spatial structure and life history diversity of Columbia River salmon...

  3. 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...

  4. 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 estuarys contribution to the spatial structure and life history diversity of Columbia River salmon...

  5. 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...

  6. Columbia River Estuary Ecosystem Classification Cultural Features

    Science.gov (United States)

    Cannon, Charles M.; Ramirez, Mary F.; 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 mapping extent is the interpreted Holocene geologic floodplain of the tidal Columbia River and its tributaries to the estimated head of tide. Cultural features within the Holocene floodplain were mapped by visual interpretation of Light Detection and Ranging (LiDAR) topography supplemented with aerial photographs and U.S. Geological Survey topographic maps. Mapped cultural features are classified as to their purpose when constructed. Because features were drawn based on LiDAR topography, only features with a significant topographic expression are mapped.

  7. 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 salinity intrusion length and the transport of salt into the estuary. The overall effects of human intervention in the physical processes of the Columbia River Estuary (i.e. decrease in freshwater inflow, tidal prism, and mixing; increase in flushing time and fine sediment deposition, and net accumulation of sediment) are qualitatively similar to those observed in less energetic and more obviously altered estuarine systems. A concurrent reduction in wetland habitats has resulted in an estimated 82% reduction in emergent plant production and a 15% reduction in benthic macroalgae production, a combined production loss of 51,675 metric tons of organic carbon per year. This has been at least partially compensated by a large increase in the supply of riverine detritus derived from freshwater phytoplankton primary production. Comparison of modern and estimated preregulation organic carbon budgets for the estuary indicates a shift from a food web based on comparatively refractory macrodetritus derived from emergent vegetation to one involving more labile microdetritus derived from allochthonous phytoplankton. The shift has been driven by human-induced changes to the physical environment of the estuary. While this is a relatively comprehensive study of historical physical changes, it is incomplete in that the sediment budget is still uncertain. More precise quantification of the modern estuarine sediment budget will require both a better understanding of the fluvial input and dredging export terms and a sediment tranport model designed to explain historical changes in the sediment budget. Oceanographic studies to better determine the mechanisms leading to the formation of the turbidity maximum are also needed. The combination of cartography and modelling used in this study should be applicable in other systems where large changes in morphology have occurred in historical time.

  8. 76 FR 8345 - Endangered and Threatened Species; Recovery Plan Module for Columbia River Estuary Salmon and...

    Science.gov (United States)

    2011-02-14

    ...Plan Module for Columbia River Estuary Salmon and Steelhead AGENCY: National Marine...plan module for Columbia River estuary salmon and steelhead...Species Act (ESA) Recovery Plan Module for Salmon and Steelhead (Estuary Module)....

  9. Tritium in the Savannah River estuary and adjacent marine waters

    International Nuclear Information System (INIS)

    The tritium distribution in the Savannah River estuary and adjacent marine waters was measured to provide information on the dilution, mixing and movement of Savannah River water in this region. The Savannah River marine region was chosen because the average tritium concentration in this river is approximately 5 pCi/ml, whereas other rivers in the southeastern United States of America average less than 0.5 pCi/ml. The increased tritium concentration in the Savannah River is due to releases from the Savannah River Plant of the Department of Energy. Tritium measurements have proved particularly effective in estimating the flushing time of the Savannah River estuary (2.4 days) and in delineating the relative contribution to the water masses in Ossabaw and Port Royal Sounds from the river and from sea-water. Ossabaw and Port Royal Sounds are located approximately 20 km south and north of the Savannah River estuary respectively. (author)

  10. Radiocesium transport in the Hudson River Estuary

    International Nuclear Information System (INIS)

    Concentrations of the major radionuclides released to the Lower Hudson River Estuary in liquid waste from a light water power reactor have been measured in samples of water, sediment, and biota. The environmental data have been used to identify and quantitate the principal processes controlling the long-term average distributions and rates of transfer of reactor-released 137Cs and 134Cs among the components of the estuarine environment. Equilibrium distributions of radiocesium between suspended and dissolved states are expressed as a function of salinity, and rates of transfer to and from bottom sediment are estimated. Desorption during intrusion of saline water is discussed as the primary mechanism for the removal of radiocesium from bottom sediment at the reactor site. Models for estimation of monthly average concentrations in water are constructed and evaluated. Accumulation of radiocesium by fish indigenous to the estuary is shown to be an order of magnitude lower than would be predicted by ''typical'' freshwater bioaccumulation factors, and salinity is proposed as the primary environmental factor influencing accumulation. A model incorporating the effect of seasonal fluctuations in salinity at the reactor site is tested against observed concentrations of radiocesium in fish

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

    International Nuclear Information System (INIS)

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

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

    Scientific Electronic Library Online (English)

    Stephen, Hosking.

    Full Text Available Estuarine habitats are subject to increasing demand pressures. Some of these are direct, for the appealing space they provide for residences and recreation; and some are indirect, in the form of competitive demand for the inputs required to maintain their ecological functionality, for instance, rive [...] r inflows. As a result of increasing demand for river water the connection of many of South Africa's estuaries with the sea has been undermined and their recreational appeal reduced. This paper reports findings on these negative impacts for selected estuaries. The contingent valuation method was used to estimate the value of recreational benefits that would result at 40 South African estuaries if water-inflow reductions were averted. The studies were undertaken between 2000 and 2007. All the estuaries selected were known to be vulnerable to changes in river inflows. Expert opinions on the consequences of specified hypothetical changes to water inflows into estuaries were used to generate the scenarios valued. User populations were estimated and surveys administered to samples of these populations. From the elicited responses median estuary user willingness to pay bids were predicted using Tobit and OLS models. An internal credibility assessment was conducted over the plausibility of the predictive model, the consistency of the values to those estimated using an alternative valuation method (the contingent travel cost method), and the reliability of the estimates. For the 37 estimates deemed reliable (but not necessarily valid), the average of the predicted median values of river inflow into estuaries was calculated to be 3.4 c/m³ (South African cents, ZAR) and standard deviation 3.84 c/m³. The average of the predicted mean values was calculated to be 7.4 c/m³ and the standard deviation 6.7 c/m³. It was also found that where there had been extensive economic development around the river system, the values of inflows into estuaries tended to be less than the value of water abstracted upstream.

  13. 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.

  14. 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

    -1 Fluxes of Nitrogen in Chaliyar River Estuary, India JOSE K. XAVIER1, T. JOSEPH2# AND J.S. PAIMPILLIL3 1 Dept of Chemistry, St. Thomas College, Palai, Kottayam Dt., Kerala, India 2 Regional Center, National Institute of Oceanography, Salim Ali Road...

  15. Trace elements distribution in bottom sediments from Amazon River estuary

    International Nuclear Information System (INIS)

    The Amazon River discharges into a dynamic marine environment where there have been many interactive processes affecting dissolved and particulate solids, either those settling on the shelf or reaching the ocean. Trace elemental concentration, especially of the rare earth elements, have been determined by neutron activation analysis in sixty bottom sediment samples of the Amazon River estuary, providing information for the spatial and temporal variation study of those elements. (author). 16 refs, 6 figs, 3 tabs

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

    Science.gov (United States)

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

    2005-01-01

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

  17. Environmental restoration of the Guadiaro river estuary, Cadiz (Spain)

    OpenAIRE

    De la Casa, Ángel; Gomez-Pina, Gregorio; Acha Martin, Antonio; Muñoz-Perez, Juan J.

    2000-01-01

    During 1998, the Spanish Ministry of Environmental Protection has developed the restoration of the Guadiaro estuary, near the Strait of Gibraltar, through the Coastal General Directorate. The main environmental problems, amongst others, detected at the area were a high eutrophication level of the estuarine waters and fish mortality mainly due to the low summer river effluent, the urban sewage inputs and no tidal renovation caused by the blockage of the sand bar at the mouth...

  18. Analysis of coastal evolution of the Pearl river estuary based on remote sensing and GIS

    OpenAIRE

    Xu, Y.; Zheng, J.; Zhang, W.; Zhao, Y

    2013-01-01

    The Pearl River Estuary is located midway along the northern boundary of the South China Sea. According to the impacts of large-scale human activities, the shape of coastline, topographical feature and the ocean dynamical environment of the Pearl River estuary have changed significantly since 1970s. In this paper, the integrated application of remote sensing and GIS technology was used to analyze the shoreline evolution in the Pearl River estuary over the past nearly 30 years. In addition, a ...

  19. The Caloosahatchee River Estuary: a monitoring partnership between Federal, State, and local governments, 2007-13

    Science.gov (United States)

    Patino, Eduardo

    2014-01-01

    The tidal Caloosahatchee River and downstream estuaries have substantial environmental, recreational, and economic value for southwest Florida residents and visitors. Modifications to the Caloosahatchee River watershed have altered the predevelopment hydrology, thereby threatening the environmental health of estuaries in the area. Hydrologic monitoring of the freshwater contributions from tributaries to the tidal Caloosahatchee River and its estuaries is necessary to adequately describe the total freshwater inflow and constituent loads to the delicate estuarine system.

  20. 75 FR 17382 - Small Takes of Marine Mammals Incidental to Specified Activities; Russian River Estuary Water...

    Science.gov (United States)

    2010-04-06

    ... small numbers of marine mammals, by Level B harassment, incidental to Russian River Estuary (Estuary... Federal Register (74 FR 58248) for the take of marine mammals incidental to Estuary water level management... notice (74 FR 58248). In summary, harbor seals are the most abundant marine mammal found at the mouth...

  1. Oil spill response planning on the Columbia river estuary

    International Nuclear Information System (INIS)

    The Columbia River Estuary lies along the Washington-Oregon state boundary on the west coast of the United States. The entire area is environmentally very sensitive with numerous large, shallow bays, exposed mud flats, wetland areas, and central channels having maximum currents of three to four knots. These features make the area very difficult to protect from an oil spill. Spill response is further complicated because of the many different state, federal, and local jurisdictions with mandated responsibilities in oil spill response and environmental protection. Under the leadership of the US Coast Guard Marine Safety Office in Portland, Oregon, a steering group was established to guide the development of a response plan for the Columbia River Estuary. A concerted effort was made to include representatives from response organizations, natural resource agencies, and resource users from federal, state, and local governments, and commercial sectors in the planning process. The first draft of an operational response plan was completed the summer of 1992 through a combination of technical workshops, field trips, and small working groups meeting with local communities. The Columbia River Estuary Response Plan prioritizes areas to protect; identifies specific response strategies for protecting these areas; and outlines the Iogistics needed to implement these strategies, including equipment needs, the location of staging areas, and the identification of pre-designed command posts. The local spill response cooperative and oil transportation industry are using the plan to coordinate the purchase of response equipment and the staging of this equipment at numerous locations along the river. The key to success is ensuring that all the groups responding to an event participate in the planning process together. This process has worked well and will serve as a model for response planning for other areas along the Columbia River and coastal areas of Washington and Oregon

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

    International Nuclear Information System (INIS)

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

  3. Local flows in the Quequen Grande River Estuary, Argentina

    Energy Technology Data Exchange (ETDEWEB)

    Pereyra, M G; Marino, B M [Instituto de Fisica Arroyo Seco, Universidad Nacional del Centro de la Provincia de Buenos Aires, Pinto 399, 7000 Tandil (Argentina); Thomas, L P, E-mail: mpereyra@exa.unicen.edu.a, E-mail: lthomas@exa.unicen.edu.a, E-mail: bmarino@exa.unicen.edu.a

    2009-05-01

    Quequen Grande River is one of the most important water courses of Buenos Aires Province due to the economic and strategic significance of its estuary, where the populous Quequen-Necochea area and Quequen Port are located. The minor Las Cascadas falls, at 15 km from the place where the river meets the sea is the point where the maximum tidal propagation is detected marking the head of the estuary. Artificial dredging is needed to insure the adequate navigability conditions in the Quequen harbour, which has induced a highly stratified water column in the last 2 km of the estuary. Thus, an abrupt step is established at the head of the harbour, implying a much reduced water circulation and in some cases nonexistent, producing strong reductive and even anoxic conditions. The foot of the step is a sediment and organic matter trap and becomes an interesting place of study. The goal of this article is to present the information obtained with Doppler sonar at the neighborhood of the step, which allows distinguishing local turbidity currents that may influence the deposition patterns of the sediments.

  4. Local flows in the Quequen Grande River Estuary, Argentina

    International Nuclear Information System (INIS)

    Quequen Grande River is one of the most important water courses of Buenos Aires Province due to the economic and strategic significance of its estuary, where the populous Quequen-Necochea area and Quequen Port are located. The minor Las Cascadas falls, at 15 km from the place where the river meets the sea is the point where the maximum tidal propagation is detected marking the head of the estuary. Artificial dredging is needed to insure the adequate navigability conditions in the Quequen harbour, which has induced a highly stratified water column in the last 2 km of the estuary. Thus, an abrupt step is established at the head of the harbour, implying a much reduced water circulation and in some cases nonexistent, producing strong reductive and even anoxic conditions. The foot of the step is a sediment and organic matter trap and becomes an interesting place of study. The goal of this article is to present the information obtained with Doppler sonar at the neighborhood of the step, which allows distinguishing local turbidity currents that may influence the deposition patterns of the sediments.

  5. Expertise mission at the Rance river estuary

    International Nuclear Information System (INIS)

    The Rance tidal power plant was inaugurated in 1968. This report presents the environmental impacts of the dam (choking up of Rance river with marine sediments) and proposes several remedial actions for the preservation of the site: dredging and agricultural valorization of muds by spreading. This project leads to several questions which are analyzed in the document: populations reaction, salinity of muds, dimensions of the decantation pool, impact of muds on cultures, lack of alternative solutions etc.. (J.S.)

  6. 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.

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

    International Nuclear Information System (INIS)

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

  8. Trace metals geochemistry of Bengkulu river and estuary

    Science.gov (United States)

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

    2015-09-01

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

  9. Lidar monitoring of organic matter in the Pearl River Estuary

    Science.gov (United States)

    Chen, Peng; Pan, Delu; Hu, Chuanwen; Mao, Zhihua

    2014-11-01

    A dual-wavelength lidar fluorosensor system for fast diagnosis of chromophoric dissolved matter (CDOM) in water in the Pearl River estuary was discussed. The laser-induced fluorescence (LIF) system used two lasers as excitation sources with wavelength at 355nm and 532 nm, and a hyperspectral CCD spectrometer was used to record the fluorescence signal. The overlapping fluorescence spectra of water Raman scattering and CDOM were separated with fitting bi- Gaussian of the least squares method. High correlation was observed between concentration of CDOM and fluorescence normalized to water Raman scattering. The in situ results demonstrated rapid characterization of dissolved organic matter can be done by the LIF technique.

  10. Where river and tide meet: The morphodynamic equilibrium of alluvial estuaries

    Science.gov (United States)

    Bolla Pittaluga, Michele; Tambroni, Nicoletta; Canestrelli, Alberto; Slingerland, Rudy; Lanzoni, Stefano; Seminara, Giovanni

    2015-01-01

    We investigate the morphodynamic equilibrium of tidally dominated alluvial estuaries, extending previous works concerning the purely tidal case and the combined tidal-fluvial case with a small tidal forcing. We relax the latter assumption and seek the equilibrium bed profile of the estuary, for a given planform configuration with various degrees of funneling, solving numerically the 1-D governing equation. The results show that with steady fluvial and tidal forcings, an equilibrium bed profile of estuaries exists. In the case of constant width estuaries, a concave down equilibrium profile develops through most of the estuary. Increasing the amplitude of the tidal oscillation, progressively higher bed slopes are experienced at the mouth while the river-dominated portion of the estuary experiences an increasing bed degradation. The fluvial-marine transition is identified by a "tidal length" that increases monotonically as the river discharge and the corresponding sediment supply are increased while the river attains a new morphological equilibrium configuration. Tidal length also increases if, for a fixed river discharge and tidal amplitude, the sediment flux is progressively reduced with respect to the transport capacity. In the case of funnel-shaped estuaries the tidal length strongly decreases, aggradation is triggered by channel widening, and tidal effects are such to enhance the slope at the inlet and the net degradation of the river bed. Finally, results suggest that alluvial estuaries in morphological equilibrium cannot experience any amplification of the tidal wave propagating landward. Hence, hypersynchronous alluvial estuaries cannot be in equilibrium.

  11. Methane and nitrous oxide emissions from a subtropical estuary (the Brisbane River estuary, Australia)

    Energy Technology Data Exchange (ETDEWEB)

    Musenze, Ronald S.; Werner, Ursula [Advanced Water Management Centre (AWMC), the University of Queensland, Brisbane, Qld 4072 (Australia); Grinham, Alistair [Advanced Water Management Centre (AWMC), the University of Queensland, Brisbane, Qld 4072 (Australia); School of Civil Engineering, the University of Queensland, Brisbane, Qld 4072 (Australia); Udy, James [Healthy Waterways Ltd, P.O. Box 13086, George Street, Brisbane, Qld 4003 (Australia); Yuan, Zhiguo, E-mail: z.yuan@awmc.uq.edu.au [Advanced Water Management Centre (AWMC), the University of Queensland, Brisbane, Qld 4072 (Australia)

    2014-02-01

    Methane (CH{sub 4}) and nitrous oxide (N{sub 2}O) are two key greenhouse gases. Their global atmospheric budgeting is, however, flout with challenges partly due to lack of adequate field studies determining the source strengths. Knowledge and data limitations exist for subtropical and tropical regions especially in the southern latitudes. Surface water methane and nitrous oxide concentrations were measured in a subtropical estuarine system in the southern latitudes in an extensive field study from 2010 to 2012 and water–air fluxes estimated using models considering the effects of both wind and flow induced turbulence. The estuary was found to be a strong net source of both CH{sub 4} and N{sub 2}O all-year-round. Dissolved N{sub 2}O concentrations ranged between 9.1 ± 0.4 to 45.3 ± 1.3 nM or 135 to 435% of atmospheric saturation level, while CH{sub 4} concentrations varied between 31.1 ± 3.7 to 578.4 ± 58.8 nM or 1210 to 26,430% of atmospheric saturation level. These results compare well with measurements from tropical estuarine systems. There was strong spatial variability with both CH{sub 4} and N{sub 2}O concentrations increasing upstream the estuary. Strong temporal variability was also observed but there were no clear seasonal patterns. The degree of N{sub 2}O saturation significantly increased with NO{sub x} concentrations (r{sup 2} = 0.55). The estimated water–air fluxes varied between 0.1 and 3.4 mg N{sub 2}O m{sup ?2} d{sup ?1} and 0.3 to 27.9 mg CH{sub 4} m{sup ?2} d{sup ?1}. Total emissions (CO{sub 2}-e) were N{sub 2}O (64%) dominated, highlighting the need for reduced nitrogen inputs into the estuary. Choice of the model(s) for estimation of the gas transfer velocity had a big bearing on the estimated total emissions. - Highlights: • The estuary is a strong source of atmospheric methane and nitrous oxide. • Emissions had strong spatial-temporal variability with unclear seasonal patterns. • Dissolved gas saturation comparable to that in tropical rivers and polluted estuaries. • Emissions are dominated by N2O, which positively correlated with NOx concentrations. • Currently existing models contribute to uncertainty in emission estimates.

  12. Methane and nitrous oxide emissions from a subtropical estuary (the Brisbane River estuary, Australia)

    International Nuclear Information System (INIS)

    Methane (CH4) and nitrous oxide (N2O) are two key greenhouse gases. Their global atmospheric budgeting is, however, flout with challenges partly due to lack of adequate field studies determining the source strengths. Knowledge and data limitations exist for subtropical and tropical regions especially in the southern latitudes. Surface water methane and nitrous oxide concentrations were measured in a subtropical estuarine system in the southern latitudes in an extensive field study from 2010 to 2012 and water–air fluxes estimated using models considering the effects of both wind and flow induced turbulence. The estuary was found to be a strong net source of both CH4 and N2O all-year-round. Dissolved N2O concentrations ranged between 9.1 ± 0.4 to 45.3 ± 1.3 nM or 135 to 435% of atmospheric saturation level, while CH4 concentrations varied between 31.1 ± 3.7 to 578.4 ± 58.8 nM or 1210 to 26,430% of atmospheric saturation level. These results compare well with measurements from tropical estuarine systems. There was strong spatial variability with both CH4 and N2O concentrations increasing upstream the estuary. Strong temporal variability was also observed but there were no clear seasonal patterns. The degree of N2O saturation significantly increased with NOx concentrations (r2 = 0.55). The estimated water–air fluxes varied between 0.1 and 3.4 mg N2O m−2 d−1 and 0.3 to 27.9 mg CH4 m−2 d−1. Total emissions (CO2-e) were N2O (64%) dominated, highlighting the need for reduced nitrogen inputs into the estuary. Choice of the model(s) for estimation of the gas transfer velocity had a big bearing on the estimated total emissions. - Highlights: • The estuary is a strong source of atmospheric methane and nitrous oxide. • Emissions had strong spatial-temporal variability with unclear seasonal patterns. • Dissolved gas saturation comparable to that in tropical rivers and polluted estuaries. • Emissions are dominated by N2O, which positively correlated with NOx concentrations. • Currently existing models contribute to uncertainty in emission estimates

  13. Desorption of Ba and 226Ra from river-borne sediments in the Hudson estuary

    International Nuclear Information System (INIS)

    The pronounced desorption of Ba and 226Ra from river-borne sediments in the Hudson estuary can be explained quantitatively by the drastic decrease in the distribution coefficients of both elements from a fresh to a salty water medium. The desorption in estuaries can augment, at least, the total global river fluxes of dissolved Ba and 226Ra by one and nine times, respectively. The desorption flux of 226Ra from estuaries accounts for 17-43% of the total 226Ra flux from coastal sediments. Two mass balance models depicting mixing and adsorption-desorption processes in estuaries are discussed. (Auth.)

  14. Man-induced regime shifts in small estuaries: II. A comparison of rivers

    OpenAIRE

    Winterwerp, J.C.; Wang, Z.B.; Van Braeckel, A.; van Holland, G.; Kösters, F.

    2013-01-01

    This is Part II of two papers on man-induced regime shifts in small, narrow, and converging estuaries, with focus on the interaction between effective hydraulic drag, fine sediment import, and tidal amplification, induced by river engineering works, e.g., narrowing and deepening. Paper I describes a simple linear analytical model for the tidal movement in narrow, converging estuaries and a conceptual model on the response of tidal rivers to river engineering works. It is argued that such engi...

  15. Sediment source identification and residence times in the Maroochy River estuary, southeast Queensland, Australia

    Science.gov (United States)

    Douglas, G.; Caitcheon, G.; Palmer, M.

    2009-04-01

    Identification of sediment sources and associated nutrients and contaminants is crucial to the ecological management of aquatic systems. A combination of geochemical and radionuclide tracing techniques and geostatistical modelling have been used to determine the primary source areas of fine sediment delivered to the Maroochy River estuary. The application of radionuclide (137Cs and 210Pb) techniques indicate that approximately 70% of the sediment in the Maroochy River estuary originates from subsoil erosion. An average of 60% of sediment in the lower estuary originates from soils developed on the Landsborough Sandstone, with 35% coming from soils developed on granitoids. In the mid-Maroochy River estuary major contributions of fine sediment come from soils developed on Landsborough Sandstone (38%) and granitoids (36%). Estimated sediment residence times in the Maroochy River estuary are generally less than 30 years, however, one sample site near the estuary mouth had an estimated residence time of at least 30 years. This indicates that sediment accumulation rates in mangroves along the estuary margins are relatively low. Results from this study will be used by catchment managers to better target remedial action to reduce fine sediment delivery to the Maroochy River estuary.

  16. Plutonium AMS measurements in Yangtze River estuary sediment

    Energy Technology Data Exchange (ETDEWEB)

    Tims, S.G., E-mail: steve.tims@anu.edu.a [Department of Nuclear Physics, Research School of Physics and Engineering, Australian National University, Canberra, ACT 0200 (Australia); Pan, S.M.; Zhang, R. [Key Lab of Ministry of Education of Coast and Island Development, Nanjing University, Nanjing 210093 (China); Fifield, L.K. [Department of Nuclear Physics, Research School of Physics and Engineering, Australian National University, Canberra, ACT 0200 (Australia); Wang, Y.P.; Gao, J.H. [Key Lab of Ministry of Education of Coast and Island Development, Nanjing University, Nanjing 210093 (China)

    2010-04-15

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

  17. Plutonium AMS measurements in Yangtze River estuary sediment

    International Nuclear Information System (INIS)

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

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

    OpenAIRE

    Hubert, Francoise; Moisan, Karine; Munschy, Catherine; Tronczynski, Jacek

    2012-01-01

    Highly mutagenic compounds such as some PAHs have been identified in surface waters and sediments of the Seine river estuary. Suspended particulate matter (SPM) represents a dynamic medium that may contribute to the exposure of aquatic organisms to toxic compounds in the water column of the estuary. In order to investigate major sources of mutagenic contaminants along the estuary, water samples were taken at 25 in downstream of the outlet of an industrial wastewater-treatment plant (WWTP). SP...

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

    OpenAIRE

    Drago Maguš

    2009-01-01

    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...

  20. 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.

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

    Science.gov (United States)

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

    2016-02-15

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

  2. 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...

  3. 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...

  4. 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...

  5. An autonomous underwater vehicle "Maya", for monitoring coastal waters, estuaries, rivers and dams

    Digital Repository Service at National Institute of Oceanography (India)

    Mascarenhas, A.A.M.Q.; Navelkar, G.S.; Madhan, R.; Dabholkar, N.A.; Prabhudesai, S.P.; Maurya, P.K.; Desa, E.; Afzulpurkar, S.; Suresh, T.; Matondkar, S.G.P.; Mahalunkar, A.

    This article demonstrates the use of Maya, Autonomous Underwater Vehicle (AUV) for monitoring coastal waters, estuaries, rivers and dams. Maya is a mono hull structure with detachable nose and tail cones. The nose cone is mission specific...

  6. Distribution of clay minerals in surface sediments off Yangtze River estuary.

    OpenAIRE

    Lan, Xianhong; Zhang, Zhixun; Li, Rihui; Wang, Zhongbo; Chen, Xiaohui; Tian, Zhenxing

    2012-01-01

    Based on the clay minerals, content analysis from 187 stations in the surface sediments, this paper dealt with the assemblages and the distributions of clay minerals in the surface sediments off the Yangtze River estuary. The research results showed that the illite dominates the surface sediments off the Yangtze River estuary with the smectite or kaolinite the second rank and chlorite the third rank; the illite-smectite- kaolinite- chlorite-assemblage is the main type of the clay minerals ass...

  7. 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.

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

    Science.gov (United States)

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

    1993-01-01

    The Tinto and Odiel rivers drain 100 km from the Rio Tinto sulphide mining district, and join at a 20-km long estuary entering the Atlantic Ocean. A reconnaissance study of heavy metal anomalies in channel sand and overbank mud of the river and estuary by semi-quantitative emission dc-arc spectrographic analysis shows the following upstream to downstream ranges in ppm (??g g-1): As 3,000 to heavy metals in the overbank clay throughout the river and estuary systems indicates the importance of suspended sediment transport for dispersing heavy metals from natural erosion and anthropogenic mining activities of the sulfide deposit. The organic-poor (0.21-0.37% TOC) river bed sand has been analyzed to represent bedload transport of naturally-occurring sulfide minerals. The sand has high concentrations of metals upstream but these decrease an order of magnitude in the lower estuary. Although heavy metal contamination of estuary mouth beach sand has been diluted to background levels estuary mud exhibits increased contamination apparently related to finer grain size, higher organic carbon content, precipitation of river-borne dissolved solids, and input of anthropogenic heavy metals from industrial sources. The contaminated estuary mud disperses to the inner shelf mud belt and offshore suspended sediment, which exhibit metal anomalies from natural erosion and mining of upstream Rio Tinto sulphide lode sources (Pb, Cu, Zn) and industrial activities within the estuary (Fe, Cr, Ti). Because heavy metal contamination of Tinto-Odiel river sediment reaches or exceeds the highest levels encountered in other river sediments of Spain and Europe, a detailed analysis of metals in water and suspended sediment throughout the system, and epidemiological analysis of heavy metal effects in humans is appropriate. ?? 1993 Estuarine Research Federation.

  9. River input of dissolved uranium to the oceans; the Zaire river and estuary

    International Nuclear Information System (INIS)

    A systematic sampling survey was carried out in the Zaire (Congo) river and estuary during November 1976 and May 1978. Dissolved 238U and 234U concentrations in filtered fresh waters are low. Simple mixing between fresh and seawater accounts for dissolved uranium concentrations in the estuary but it was not possible to confirm the predicted conservative behaviour of riverine uranium by comparison of its distribution with the theoretical dilution curve. Uranium removal in near-bottom samples taken from the almost anoxic water-body located near the head of the canyon probably accounts for the lower concentrations found in these samples. Data concerning dissolved 238U in world rivers are well correlated with total dissolved solids. This correlation permits a reassessment of 238U concentration in rivers flowing to the ocean resulting in a world wide estimate of 0.24 ?g/l. The dissolved river input of 238U to the ocean is comparable with output through the main sink processes

  10. Salinity intrusions into the Selangor River estuary and its effect on the mangrove species sonneratia caseolaris

    International Nuclear Information System (INIS)

    Vertical profiles of salinity, temperature and suspended sediment concentration (using OBS sensors) were measured along the longitudinal axis of the Sungai Selangor estuary during neap and spring high waters for different river discharges. These were supplemented by anchor station measurements (Which include tidal current velocity) in the lower and middle of the estuary over neap and spring tidal cycles. The results of these measurements showed that for low and medium river discharges the estuary changed from partially-mixed during the neaps to a well -mixed one during the springs. During high river discharges, the estuary became a salt-wedge type for both neap and spring tidal cycles. The maximum limit of salt water intrusion reached some 16 km from the river mouth which was recorded during a low river discharges (6.0 m3/s) on a medium tide ( tidal range 3.2 m), but this was reduced to about half the distance during high river discharges. During the maximum intrusion, the salt water did not reach Kg Kuantan, the attraction centre for the fireflies display, which dwells on mangrove species sonneratia caseolaris (Beremban trees). The measurements also indicated that the mangrove species was not found in the lower estuary where the salinity frequently exceeded 10 ppt. However, these trees grow along the river banks upstream of Kg Kuantan where it could occasionally exposed to salt water. This indicates that the salinity has some influence on the distribution of sonneratia caseolaris along Sungai Selangor and this natural balance shall maintained. (Author)

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

    Science.gov (United States)

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

    2011-03-01

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

  12. Using a Multi-Component Indicator Toward Reducing Phytoplankton Bloom Occurrences in the Swan River Estuary

    Science.gov (United States)

    Kristiana, Ria; Antenucci, Jason P.; Imberger, Jorg

    2012-08-01

    The Swan River estuary is an icon of the city of Perth, Western Australia, running through the city centre and dividing the northern from the southern part of the city. However, frequent phytoplankton blooms have been observed in the estuary as a result of eutrophication. The Index of Sustainable Functionality (ISF), a composite index able to indicate for sustainable health of the estuary, was applied, taking into account the hydrology and highly seasonal nature of the estuary to inform the management of the estuary, towards the aim of reducing bloom occurrences. The study period was from the beginning of intensive monitoring in 1995 to mid-2009. The results emphasize the importance of physical controls on the ecology of the estuary. No significant trend in the estuary's low functionality was found, indicating that despite extensive restoration efforts, the frequency of algal bloom occurrences has remained relatively stationary and other mitigating factors have maintained an annual average ISF value at around 70 % functionality. We identified that the low flow season consistently performs the worst, with (high) temperature found as the most dominant variable for phytoplankton growth and bloom. Thus in managing the estuary, vigilance is required during periods of high temperature and low flow. Focusing on the risk of phytoplankton bloom, a nutrient reduction program that is in place is a long term solution due to high concentrations in the estuary. Other management measures need to be considered and adopted to effectively reduce the occurrences of future phytoplankton blooms.

  13. 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 for the estuary are monitored indicators that reflect the status of habitat conditions and fish performance, e.g., habitat connectivity, survival, and life history diversity. Performance measures also pertain to implementation and compliance. Such measures are part of the monitoring, research, and action plans in this estuary RME document. Performance targets specific to the estuary were not included in the 2007 draft Biological Opinion.

  14. 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.

  15. 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.

  16. Distribution, Isolation, Host Specificity, and Diversity of Cyanophages Infecting Marine Synechococcus spp. in River Estuaries†

    OpenAIRE

    Lu, Jingrang; Chen, Feng; Hodson, Robert E.

    2001-01-01

    The abundance of cyanophages infecting marine Synechococcus spp. increased with increasing salinity in three Georgia coastal rivers. About 80% of the cyanophage isolates were cyanomyoviruses. High cross-infectivity was found among the cyanophages infecting phycoerythrin-containing Synechococcus strains. Cyanophages in the river estuaries were diverse in terms of their morphotypes and genotypes.

  17. 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.

  18. Structure and Seasonal Dynamics of Larval Fish in the Caeté River Estuary in North Brazil

    Science.gov (United States)

    Barletta-Bergan, A.; Barletta, M.; Saint-Paul, U.

    2002-02-01

    The larval fish assemblage was examined along a salinity gradient of the Caeté River Estuary situated in northern Brazil. A total of 35 555 larvae, representing 28 families and 63 taxa were collected in samples taken monthly between July 1996 and September 1997, with a mean concentration of 9 individuals per 100 m 3. Sciaenidae was the most abundant family comprising 46·5% (11 species) of all teleosts sampled in the Caeté River Estuary, followed by Engraulidae (41·9%, seven species). The most abundant larval taxa were the engraulid Anchovia clupeoides and the sciaenid Stellifer microps accounting together for 70·4% of the total catch. The most abundant developmental stages of A. clupeoides was preflexion larva, confirming that this species is resident. Apart from estuarine species, the upper estuary additionally has taxa associated with freshwater conditions, whereas species with marine affinities were captured in the lower estuary. The densities of most species were influenced to a greater degree by site than by season, showing maximum densities in the upper estuary. Larval density peaked in the upper estuary during the dry season and was lowest when freshwater discharge was at its maximum, which was attributed to an increased seaward drift of larvae. Species number was greatest in the upper estuary between the rainy and dry season.

  19. Man-made radionuclides and sedimentation in the Hudson River Estuary

    International Nuclear Information System (INIS)

    Recently deposited fine-grained sediments in the Hudson River estuary contain radionuclides from global fallout produced by atmospheric bomb tests as well as from low-level releases of a local nuclear reactor. Accumulation rates of these nuclides are dependent on rates of sediment deposition and vary with location in the estuary by more than two orders of magnitude. Within the Hudson estuary, New York harbor is currently the zone of most rapid deposition of sediments containing radionuclides, some of which were released from a nuclear reactor about 60 kilometers upstream of the harbor

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

    Science.gov (United States)

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

    2012-01-24

    Highly mutagenic compounds such as some PAHs have been identified in surface waters and sediments of the Seine river estuary. Suspended particulate matter (SPM) represents a dynamic medium that may contribute to the exposure of aquatic organisms to toxic compounds in the water column of the estuary. In order to investigate major sources of mutagenic contaminants along the estuary, water samples were taken at 25 m downstream of the outlet of an industrial wastewater-treatment plant (WWTP). SPM samples were analyzed for their genotoxicity with two short-term tests, the Salmonella typhimurium mutagenicity assay (TA98+S9 mix) and the comet assay in the human HepG2 cell line. Sampling sites receiving effluents from a chemical dye industry and WWTP showed the highest mutagenic potencies, followed by petrochemical industries, petroleum refinery and pulp and paper mills. These data indicate that frame-shift mutagens are present in the Seine river estuary. Furthermore, the comet assay revealed the presence of compounds that were genotoxic for human hepatocytes (HepG2 cells). We also observed a high level of mutagenic potency in the sediment of the lower estuary (3 × 10? revertants/g). The source of mutagenic and genotoxic compounds seems to be associated with various types of effluents discharged in the Seine river estuary. Both test systems resulted in the same assessment of the genotoxicity of particulate matter, except for three of the 14 samples, underlying the complementarity of bioassays. PMID:22079610

  1. Occurrences of dissolved trace metals (Cu, Cd, and Mn) in the Pearl River Estuary (China), a large river-groundwater-estuary system

    Science.gov (United States)

    Wang, Deli; Lin, Wenfang; Yang, Xiqian; Zhai, Weidong; Dai, Minhan; Arthur Chen, Chen-Tung

    2012-12-01

    This study for the first time examined dissolved metals (Cu, Cd, and Mn) together with dissolved oxygen and carbonate system in the whole Pearl River Estuary system, from the upper rivers to the groundwater discharges until the estuarine zone, and explored their potential impacts in the adjacent northern South China Sea (SCS) during May-August 2009. This river-groundwater-estuary system was generally characterized by low dissolved metal levels as a whole, whilst subject to severe perturbations locally. In particular, higher dissolved Cu and Cd occurred in the North River (as high as 60 nmol/L of Cu and 0.99 nmol/L of Cd), as a result of an anthropogenic source from mining activities there. Dissolved Cu levels were elevated in the upper estuary near the city of Guangzhou (Cu: ˜40 nmol/L), which could be attributable to sewage and industrial effluent discharges there. Elevated dissolved metal levels (Cu: ˜20-40 nmol/L; Cd: ˜0.2-0.8 nmol/L) also occurred in the groundwaters and parts of the middle and lower estuaries, which could be attributable to a series of geochemical reactions, e.g., chloride-induced desorption from the suspended sediments, oxidation of metal sulfides, and the partial dissolution of minerals. The high river discharge during our sampling period (May-August 2009) significantly diluted anthropogenic signals in the estuarine mixing zone. Of particular note was the high river discharge (which may reach 18.5 times as high as in the dry season) that transported anthropogenic signals (as indicated by dissolved Cu and Cd) into the adjacent shelf waters of the northern SCS, and might have led to the usually high phytoplankton productivity there (chlorophyll-a value >10 ?g/L).

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

    OpenAIRE

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

    2015-01-01

    Dissolved oxygen (DO) is not only a fundamental parameter of coastal water quality, but also an indication of organics decomposed in water and their degree of eutrophication. There has been a concern about the deterioration of dissolved oxygen conditions in the Minjiang River Estuary, the longest river in Fujian Province, Southeast China. In this study, the syntheses effects on DO was analyzed by using a four year time series of DO concentration and ancillary parameters (river discharge, wate...

  3. PREDICTION OF TSUNAMI PROPAGATION IN THE PEARL RIVER ESTUARY

    Directory of Open Access Journals (Sweden)

    Sun J. S.

    2009-01-01

    Full Text Available Tsunamis entering into shallow water regions may become highly nonlinear and this may be due to the irregularity of sea bottom roughness relative to the water depth and the complex coastline geometry. The elliptic mild-slope equation is commonly used to predict the nonlinear wave propagation in shallow water regions but it requires huge amount of computer resources which may not be practical for tsunami propagation predictions. An efficient finite element approach has been adopted in the present project to resolve the nonlinear problem of wave transformation in near shore zones as well as to better conform the model grids to any complex coastline configurations. The efficient approach is based on the wave action conservation equation that takes into account of wave refraction-diffraction and energy dissipation due to bottom roughness. An operator splitting scheme is employed to solve the wave action conservation equation. Firstly, to increase numerical stability, the Eulerian-Lagrangian method is applied to solve the advection terms in the equation. The horizontal terms are then discretized by an implicit finite element method and, finally, the vertical terms are approximated by an implicit finite difference method. A nominal-time iteration method is used to efficiently solve the non-linear irrotational wave number equation for the wave direction. Over 6000 nine-node elements have been used to mesh the Pearl River estuary region. The boundary conditions are based on the results obtained from a simulation applied for a larger computation domain encompassing the entire South China Sea. The computed result provides a general picture of tsunami propagation in the desired region. Model validation and result verification, however, are necessary for any future prediction exercises.

  4. Distribution and flux of 226Ra and 228Ra in the Amazon River estuary

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2005-05-01

    The distributions of dissolved organic carbon (DOC), silica, select trace elements (Mn, Fe, Ba, Sr, Co, V,) and a suite of naturally-occurring radionuclides in the U/Th decay series (222Rn, 223,224,226,228Ra, 238U) were studied during high and low discharge conditions in the Loxahatchee River estuary, Florida. The zero-salinity endmember of this still relatively pristine estuary may reflect not only river-borne constituents, but also those advected during active groundwater/surface-water discharge. During low discharge conditions, with the notable exception of Co, trace metals indicate nearly conservative mixing from a salinity of ~12 through the estuary (This statement contracdicts with what is said in p. 7). In contrast, of the trace metals studied, only Sr, Fe, U and V exhibited conservative estuarine mixing during high discharge. Dissolved organic carbon and Si concentrations were highest at zero salinities, and generally decreased with an increase in salinity during both discharge regimes, indicating removal of land-derived dissolved organic matter and silica in the estuary. Suspended particulate matter (SPM) concentrations were generally lowest (estuary. Surface water-column 222Rn activities were most elevated (> 28 dpm L-1) at the freshwater endmember of the estuary, and appear to identify regions of the river most influenced by active submarine groundwater discharge (where is the data that show this?). Activities of four naturally-occurring isotopes of Ra (223,224,226,228Ra) in this estuary and select adjacent shallow groundwater wells indicate mean estuarine water mass residence times of less than 1 day; values in close agreement to those calculated by tidal prism and tidal period. A radium-based model for estimating submarine groundwater discharge to the Loxahatchee River estuary yielded an average of 1.03 V 3.84 x 105 m3 day-1, depending on river discharge stage as well as slight variations in the particular Ra models used. Such calculated flux estimates are in close agreement with results obtained from a 2-day electromagnetic seepage meter (0.9 x 105 m3 d-1) deployment during high discharge at the confluence of Kitching Creek and the Loxahatchee River, as well as with surficial aquifer recharge estimates. Calculated submarine ground-water discharge rates yield NH4+ and PO4-3 flux estimates to the Loxahatchee River estuary that range from 63 - 1060 ?Ymol m-2 d-1 and 69 - 379 ?Ymol m-2 d-1, respectively.

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

    Science.gov (United States)

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

    2015-12-01

    This study first examined the spatial distribution of dissolved cadmium (Cd) along with other hydrochemical parameters in a large subtropical river estuary system (the Jiulong River-Estuary, China) between 2008 and 2010, aiming to evaluate the impacts of the recently increasing anthropogenic perturbation in natural waters. The results showed that dissolved Cd was variable in the watershed with sporadically high concentrations (>0.6 nmol L-1). The significantly positive correlation of dissolved Cd with phosphate in the watershed (May 2008: dissolved Cd=0.22*P+0.0062, r=0.64, pChina's natural waters are currently subject to local perturbation due to the recently increasing anthropogenic activities.

  7. Spatial distribution of K-40 and Th-232 in recent sediments of the Krka River Estuary

    OpenAIRE

    Cukrov, Neven; Bariši?, Delko

    2006-01-01

    Spatial radionuclides distribution was studied in recent estuarine sediments in the Krka River Estuary. Sediment samples were analyzed for K-40 and Th-232 by gamma-spectrometry. Activities of K-40 were found in the range of 18-457 Bq kg(-1) and activities of Th-232 in range of 1.9-29.4 Bq kg(-1). Distribution of Th-232 activities follows that of K-40, with correlation coefficients higher than 0.97 in all analyzed samples from the Krka River estuary. Spatial distribution of natural radionuclid...

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

    International Nuclear Information System (INIS)

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

  9. Preliminary evaluation of ecological risk for the city area from the Pearl River Estuary.

    Science.gov (United States)

    Chen, Qiuying; Ho, KinChung; Liu, Jingling

    2014-01-01

    It is essential to evaluate the ecological risk for the estuary cities area for the environmental restoration of the estuary. The ecological risk of six city areas from the Pearl River Estuary were evaluated by using the relative risk model. The relative risk assessment method was developed by considering the river network density in the sub-region. The results indicated that Dongguan had the largest ecological risk pressure with total risk scores as high as 10,846.3, and Hong Kong had the lowest ecological risk pressure with total risk scores up to 4,104.6. The greatest source was domestic sewage with total risk scores as high as 1,798.6, followed by urbanization and industry. Oxygen-consuming organic pollutants, organic toxic pollutants and nutrients were the major stressors of the water environment. In terms of habitats, the water environment was enduring the greatest pressure. For the endpoints, water deterioration faced the largest risk pressure. PMID:25429453

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

    Directory of Open Access Journals (Sweden)

    Peng Zhang

    2015-08-01

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

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

    Science.gov (United States)

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

    2015-01-01

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

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

    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.

  13. 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) ...

  14. 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...

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

    Science.gov (United States)

    Kärnä, Tuomas; Baptista, António M.

    2016-03-01

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

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

    Science.gov (United States)

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

  17. 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.

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

    Science.gov (United States)

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

  19. Brackish water snails from Qi'ao-Dan'gan Island in the Pearl River estuary, China

    OpenAIRE

    LI, Ya-fang; XU, Run-lin

    2013-01-01

    Eight brackish water snails belonging to 5 families are described. All the samples were taken from 3 different types of water body. They were taken from 1 littoral of an artificial brackish lake, 1 intertidal zone of a brackish tidal river, and 3 mangrove swamps on Qi'ao Island in the Pearl River estuary, Guangdong Province, southern China. Assiminea estuarina Habe, 1946 and Iravadia (Fairbankia) cochinchinensis Bavey & Dautzenberg, 1910 are new records for China. Cerithidea sinensis...

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

    Science.gov (United States)

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

    2006-12-01

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

  1. Marine origin of Savannah river estuary sediments: evidence from radioactive and stable isotope tracers

    International Nuclear Information System (INIS)

    To determine the origin of sediments in the Savannah River estuary, we have measured 137Cs and stable isotope ratios of C, N and S in suspended particles and bottom sediments at several sites in the Savannah River and estuary and offshore on the continental shelf. The 137Cs and stable isotope data were used with a two-endmember mixing model to partition the suspended and bottom sediments at sites along a salinity gradient into riverine and marine fractions. Results from the 137Cs measurements indicated that ? 65% of inorganic sediments in suspension or in the top 5 cm of bottom deposits in the estuary were of marine origin. Stable carbon isotope ratios indicated that ?74% of the organic sediments in suspension or on the bottom of the estuary were of marine origin, except for sediments at the lowest salinity estuarine site (< 5ppt) were ? 22% of the sediments were marine-derived. Stable N and S isotope ratios were inconclusive, perhaps reflecting isotopic fractionation during sediments diagenesis at some of the sites. Our results suggest that estuaries, particularly those along submergent coastlines such as the eastern United States, are important sinks for inorganic and organic particles and particle-associated materials from the coastal ocean. (author)

  2. 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...

  3. Medium-term sediment accumulation in the urbanized lower Hudson River estuary

    Science.gov (United States)

    Zhu, J.; Wilson, B. A.; Gontz, A. M.; Tian, Y. Q.; Olsen, C. R.

    2007-12-01

    Estuaries are dynamic systems that naturally act as sediment traps at the land-ocean interface. Sediment accumulation in urbanized systems like the lower Hudson River estuary is also affected by human activities such as channelization, dredging, harbor construction, and ship traffic. Sediment accumulation in this urban estuary was examined using a unique research approach that links Geographic Information Systems (GIS) with radioisotopic (Cesium-137) dating over the medium-term (decadal to centennial) time scales. Raster analyses were performed to determine sediment accumulation/erosion patterns based on bathymetric data over the last 100 years. These results indicate that sediment accumulation was negligible in the natural river channel, where sediment surface is in equilibrium with its physical regime. Protected marginal areas (such as abandoned harbor slips) and previously dredged areas (such as around the southern tip of Manhattan Island and in the Bay Ridge Flat area) are currently sites of rapid sediment accumulation. Vertical profiles of Cesium-137 measured in sediment cores collected in the lower Hudson River estuary provided time-marker horizons that could be used to estimate sediment accumulation rates over a 40-year time span (1960-70 to 2007). Results from Cs-137 profiles confirmed the raster analyses and indicated that sediment accumulation rates ranged from 0 to 1 cm/yr in the natural river channel and subtidal bank areas, to as high as 15-20cm/yr in areas affected by human activities (Pier 32, Battery and Bay Ridge Flat). Overall, GIS and radioisotopic dating are complementary to each other and combined they provide a more accurate estimate for medium-term sediment accumulation in the lower Hudson River estuary.

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

    Science.gov (United States)

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

    2015-03-01

    The Changjiang River estuary is the most eutrophic estuary in China. Although anthropogenic input from the Changjiang River (the third-largest river in the world) is considered the main source of nitrogen, the contributions of newly regenerated nitrogen from deep waters may be underestimated, in part due to the lack of information on the nitrogen biogeochemical processes that are occurring. The nitrogen stable isotope ratio is widely used as an indicator of the source of nitrogen and nitrogen transformation processes including assimilation, nitrification, nitrogen fixation and mineralization. To study the biogeochemical processes in the Changjiang River estuary, seasonal variations in the nitrogen stable isotope ratio of nitrate (?15NO3), salinity, temperature, dissolved oxygen concentration, chlorophyll a (Chl a) concentration, and the composition of dissolved inorganic nitrogen were investigated along two transects in the estuary in 2010. In the surface waters, assimilation between May and November was suggested by high Chl a and ?15NO3 and supported by the mixing behavior of the nitrate and ?15NO3. From February to November, the mean nitrate content in the deep waters gradually increased (from ?8 to ?15 ?mol l-1), whereas the mean ?15NO3 decreased (from ?2‰ to ?-2‰). Particularly in November, most of the ?15NO3 values in the deep waters were negative (?-5‰ -0‰, which is much lower than the ?3‰ riverine input from ?15NO3), indicating that most of the nitrates in the deep water were newly regenerated from nitrification rather than originating from riverine input. Additionally, the mean ammonium abruptly increased (from ?2 to ?20 ?mol l-1) in the deep waters during November when the ?15NO3 values were negative, whereas in August, high Chl a values were observed in the deep waters. These results indicate that remineralization and nitrification occurred in the deep waters of the Changjiang River estuary, implying that regenerated nitrogen may also be an important nitrogen source for uptake by phytoplankton.

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

    Science.gov (United States)

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

    2014-12-01

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

  6. Reduced river discharge intensifies phytoplankton bloom in Godavari estuary, India

    Digital Repository Service at National Institute of Oceanography (India)

    Acharyya, T.; Sarma, V.V.S.S.; Sridevi, B.; Venkataramana, V.; Bharathi, M.D.; Naidu, S.A.; Kumar, B.S.K.; Prasad, V.R.; Bandyopadhyay, D.; Reddy, N.P.C.; DileepKumar, M.

    Changes in river discharge alter material load and the consequent estuarine and coastal biogeochemical process. Evidence for biogeochemical response to variable rainfall over catchment area or changes in river discharges due to dam regulations...

  7. Large-river delta-front estuaries as natural “recorders” of global environmental change

    OpenAIRE

    Bianchi, Thomas S.; Allison, Mead A.

    2009-01-01

    Large-river delta-front estuaries (LDE) are important interfaces between continents and the oceans for material fluxes that have a global impact on marine biogeochemistry. In this article, we propose that more emphasis should be placed on LDE in future global climate change research. We will use some of the most anthropogenically altered LDE systems in the world, the Mississippi/Atchafalaya River and the Chinese rivers that enter the Yellow Sea (e.g., Huanghe and Changjiang) as case-studies, ...

  8. 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.

  9. A case study on the impact of industrial effluent disposal on the fishery of Amba River Estuary, Maharashtra

    Digital Repository Service at National Institute of Oceanography (India)

    Gajbhiye, S.N.; Mehta, P.; Mustafa, S.; Nair, V.R.

    on this aspect a case study was conducted in the Amba River estuary before and after the establishment of a petrochemical complex at Nagothane. The treated wastewater from this complex is released through a subsurface outfall after adopting effective control...

  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-fresh reaches of the main-stem river and many tidally-influenced estuary tributaries. Finally, our surveys to date characterize wetland habitats within island complexes distributed in the main channel of the lower estuary. Yet some of the most significant wetland losses have occurred along the estuary's periphery, including shoreline areas and tributary junctions. These habitats may or may not function similarly as the island complexes that we have surveyed to date. In 2007 we initiated a second phase of the BPA estuary study (Phase II) to address specific uncertainties about salmon in tidal-fresh and tributary habitats of the Columbia River estuary. This report summarizes 2007 and 2008 Phase II results and addresses three principal research questions: (1) What was the historic distribution of estuarine and floodplain habitats from Astoria to Bonneville Dam? (2) Do individual patterns of estuarine residency and growth of juvenile Chinook salmon vary among wetland habitat types along the estuarine tidal gradient? (3) Are salmon rearing opportunities and life histories in the restoring wetland landscape of lower Grays River similar to those documented for island complexes of the main-stem estuary? Phase II extended our analysis of historical habitat distribution in the estuary above Rkm 75 to near Bonneville Dam. For this analysis we digitized the original nineteenth-century topographic (T-sheets) and hydrographic (H-sheets) survey maps for the entire estuary. Although all T-sheets (Rkm 0 to Rkm 206) were converted to GIS in 2005 with support for the USACE estuary project, final reconstruction of historical habitats throughout the estuary requires completion of the remaining H-sheet GIS maps above Rkm 75 and their integration with the T-sheets. This report summarizes progress to date on compiling the upper estuary H-sheets above Rkm 75. For the USACE estuary project, we analyzed otoliths from Chinook salmon collected near the estuary mouth in 2003-05 to estimate variability in estuary residence times among juvenile out migrants. In Phase II we expanded these a

  11. 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-restoration conditions at both the Kandoll and Vera study areas.

  12. Geochemical behaviour of plutonium isotopes in natural media (lakes, rivers, estuaries)

    International Nuclear Information System (INIS)

    Artificial radionuclide activities (238Pu, 239+240Pu) were measured in natural environments. Their distribution and geochemical behaviour are evaluated and compared them to these of the 137Cs. In a volcanic crater lake, influenced only by atmospheric fallout (Lac Pavin, France), sediments are enriched in 239+240Pu, whereas 137Cs stays in the dissolved phase. Diffusion processes and migration of radionuclides is shown to occur in sediments. Remobilization of 239+240Pu is probable at the sediment/water interface. In the Garonne-Dordogne, Seine and Loire rivers, the 239+240Pu activity levels in suspended matter are little influenced by the waste discharges of nuclear power plants. The element is essentially transported in the particulate fraction, more than is 137Cs. In all the esturies studied (Gironde, Seine, Loire) 239+240Pu concentrations in suspended matter increase between the river and the estuary. Simultaneously a removal of plutonium from the dissolved phase is observed. High plutonium concentrations are measured in the Seine estuary; they are attributed to a ''marine'' contamination: the French nuclear reprocessing plant of La Hague discharges low level radioactive liquid wastes, a part may reach the Seine estuary. There are no decrease in particulate 137Cs concentrations between the river and the estuary of the Gironde, such as it occurs in the Loire. In this last case, the phenomenon is explained by the presence of ''young caesium'' originating in the power plant effluents and which is more exchangeable than 137Cs of atmospheric origin. In the Seine estuary, the influence of marine contamination causes an increase of particulate and dissolved 137Cs concentrations

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

    Science.gov (United States)

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

    2011-01-01

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

  14. 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.

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

    International Nuclear Information System (INIS)

    Anthropogenic radionuclides (Cs137, Cs134, Co60) have been introduced to the James River estuary as a result of low-level releases from the Surry Reactor site since 1973 and worldwide atmospheric fallout from nuclear weapons tests since the early 1950s. The total radionuclide burden in the estuary sediments has been estimated by integrating radionuclide activities in 29 box cores and extrapolating these integrated values over surface areas subdivided on the basis of sediment type, rate of accumulation, and proximity to the reactor release site. The results indicate that 30% of the Co60, but only 15% of the Cs134 released from the reactor site, has been retained in the estuary sediments, and about 40% of the Cs134 and Co60 sediment inventory is in areas that represent less than 5% of the total estuarine surface area. Depletion of the Cs134 in downstream sediments forms a noticeable trend in the James River estuary, and it is postulated that seawater cation competition and exchange is primarily responsible. 26 references, 1 figure, 4 tables

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

    Science.gov (United States)

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

    1984-09-01

    Anthropogenic radionuclides (137Cs,134Cs,60Co) have been introduced to the James River estuary as a result of low-level releases from the Surry Reactor site since 1973 and worldwide atmospheric fallout from nuclear weapons tests since the early 1950s The total radionuclide burden in the estuary sediments has been estimated by integrating radionuclide activities in 29 box cores and extrapolating these integrated values over surface areas subdivided on the basis of sediment type, rates of accumulation, and proximity to the reactor release site. Our results indicate that 30% of the60Co, but only 15% of the134Cs released from the reactor site, has been retained in the estuary sediments, and about 40% of the134Cs and60Co sediment inventory is in areas that represent less than 5% of the total estuarine surface area. Depletion of the134Cs in downstream sediments forms a noticeable trend in the James River estuary, and we postulate that seawater cation competition and exchange is primarily responsible.

  17. 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 ?mol N L?1 d?1 and nitrite oxidation (0–5.2 ?mol N L?1 d?1, accompanied by extremely high concentrations of ammonia (up to >800 ?mol L?1 and nitrate (up to >300 ?mol L?1. In summer, the upper estuary showed higher nitrification rates (ammonia oxidation rate ~1.5–33.1 ?mol N L?1 d?1, nitrite oxidation rate ~0.6–32.0 ?mol N L?1 d?1 with lower concentrations of ammonia (<350 ?mol L?1 and nitrate (<120 ?mol 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 community DO consumption in the upper estuary during surveyed periods, boosting environmental stress on this large estuarine ecosystem.

  18. The redox geochemistry of cerium in river water, estuaries and the oceans

    International Nuclear Information System (INIS)

    In natural waters the rare earth elements (REE) exist in the trivalent oxidation state, apart from cerium which is the only REE which undergoes redox reactions (CeIII and IV). By comparing the abundance of Ce with its trivalent neighbors (the Ce-anomaly), a natural probe with which to understand how biogeochemical reactions can modify the redox cycles of a trace element is available. Using new and published data the author will illustrate this point with with following case studies: (1) river colloids as sites for the oxidation of Ce and (2) the development of large Ce-anomalies in the Amazon Estuary due to coagulation of river colloids at low salinity and to biological activity associated with high productivity in the outer estuary. The role that these processes in controlling the Ce-anomaly of the oceans will be addressed

  19. Spatial Distribution of Lead and Copper in the Bottom Sediments of Pahang River Estuary, Pahang, Malaysia

    International Nuclear Information System (INIS)

    Bottom sediment samples from 30 stations of Pahang River estuary collected in April 2008 were analyzed for the concentration of Pb and Cu using the Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). The average concentrations of Pb and Cu were 74.31 ± 22.97 ?g/ g dry weights and 18.65± 7.65 ?g/ g dry weights, respectively. In this study, the concentrations were significantly higher near the mouth river and declined as the sampling points were further away from the estuary. Generally, the concentrations of heavy metals were relatively low when compare with other studies in Malaysia. However, the calculated enrichment factors (EF) obtained for Pb, has a slightly higher value, and was probably influenced by anthropogenic input. The concentration for both metals increased with the decrease of mean size, suggesting their association with the fine fraction of the sediments. (author)

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

    International Nuclear Information System (INIS)

    The distribution of Triclosan within the Hudson River Estuary can be explained by a balance among the overall effluent inputs from municipal sewage treatment facilities, dilution of Triclosan concentrations in the water column with freshwater and seawater inputs, removal of Triclosan from the water column by adsorption to particles, and loss to photodegradation. This study shows that an average water column concentration of 3 ± 2 ng/l (in the lower Hudson River Estuary) is consistent with an estimate for dilution of average wastewater concentrations with seawater and calculated rates of adsorption of Triclosan to particles. An average Triclosan sediment concentration of 26 ± 11 ng/g would be in equilibrium with the overlying water column if Triclosan has a particle-to-water partitioning coefficient of kd ? 104, consistent with laboratory estimates.

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2013-12-01

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

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

    OpenAIRE

    Regla Duthit Somoza; Eusebio Perigó; Roberto Piñeiro; Lisset Susana Cobas Gómez

    2011-01-01

    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 measure...

  4. 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).

  5. Resuspension and estuarine nutrient cycling: insights from the Neuse River Estuary

    OpenAIRE

    D. R. Corbett

    2010-01-01

    For at least the past several decades, North Carolina's Neuse River Estuary (NRE) has been subject to water quality problems relating to increased eutrophication. Research studies initiated in the past several years have addressed the complex nutrient cycles in this system. Most of this research, however, is concerned with the nutrient processes of the water column and the passive diffusion processes of the benthic sedimentary environment. Resuspension of bottom sediments, by bioturbation, ti...

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

    Science.gov (United States)

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

    2016-01-15

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

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

    Directory of Open Access Journals (Sweden)

    D. C. Shaha

    2009-06-01

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

  8. 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.

  9. Remote Sensing Observation of Particulate Organic Carbon in the Pearl River Estuary

    Directory of Open Access Journals (Sweden)

    Dong Liu

    2015-07-01

    Full Text Available River estuaries are connectors of terrestrial and marine ecosystems. Riverine particulate organic carbon (POC is discharged into oceans after a series of biogeochemical reactions in estuaries. Satellite monitoring of POC will improve our understanding of the carbon dynamics of these water bodies. Based on in situ data from four seasonal survey cruises, we developed an algorithm for estimating POC concentrations in the Pearl River Estuary (PRE. Reflectance ratios, Rrs(678/Rrs(488 and Rrs(748/Rrs(412, were set as inputs to calculate POC concentration in the PRE. The algorithm was then applied to MODIS/AQUA data to inverse POC concentrations in the PRE from 2002 to 2014. Additionally, sources, impact factors, and seasonal distributions of POC were also investigated. Phytoplankton contributed more to POC in off-shore waters than that in in-shore waters in autumn and spring, but showed the opposite pattern in winter. Under the influence of freshwater from the Pearl River, underwater topography, tides, winds, etc., the seasonal POC concentrations along a specific section, vertical to water depth gradient, decreased in different seasons. These decreases could be described by exponential functions (y = aebx, b < 0. The distribution of POC concentrations in the PRE resulted from complex physical and biogeochemical processes, which can change spatially and seasonally.

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

    International Nuclear Information System (INIS)

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

  11. Trace Metal Concentration in Water of the Karnaphuli River Estuary of the Bay of Bengal

    Directory of Open Access Journals (Sweden)

    Biplob Das

    2002-01-01

    Full Text Available A study was conducted for the determination of some trace metal (Cr, Mn, Zn, Ni, Cu, Pb, Cd and Fe concentrations in water of the Karnaphuli River estuary analyzing seasonally viz., pre-monsoon, monsoon and post-monsoon by employing air acetylene flame in combination with single element hollow cathode lamps and atomic absorption spectrophotometer. Sub-surface water samples were collected from 4 stations namely Mouth, Naval base, Sadarghat and Kalurghat regions of the Karnaphuli River estuary. The concentrations (?;g g -1 dry weight of Cr, Mn, Zn, Ni, Cu, Pb, Cd and Fe were found to range from 0.421 to 0.925, 0.498 to 1.372, 0.472 to 1.186, 0.356 to 0.865, 0.372 to 0.973, 0.405 to 1.195, 0.090 to 0.217 and 20.025 to 42.203 respectively. The concentrations of Pb, Cu, Fe, Ni and Cr were observed higher and concentrations of Mn and Cd were found lower than that of the recommended values. It is assumed from the analytical findings that the estuary has been polluted from domestic sewage, land washout, river run-off and shipping activities.

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

    Science.gov (United States)

    Hayashi, Mitsuru; Yanagi, Tetsuo

    2008-01-01

    Occurrence number of red tides in Osaka Bay in Japan is more than 20 cases every year. Diatom red tide was dominant in Osaka Bay, but the non-diatom red tide was dominant in early 1990s. Therefore, the material cycling in Yodo River estuary in Osaka Bay during August from 1991 to 2000 was analyzed by using the numerical ecosystem model and field observation data to clarify the reasons of change in red tide species. Year-to-year variation in calculated concentration ratio of diatom to non-diatom corresponds to the variation in observed ratio of red tide days of diatom to non-diatom. Limiting nutrient of primary production is phosphate over the period. Diatom dominated from 1991 to 1993, but it was difficult for non-diatom to grow due to the limitation by physical condition. Non-diatom was able to grow because of good physical and nutrient conditions from 1994 to 1996. And diatom dominated again under the good physical condition, and phosphorus supply was not enough for non-diatom to grow from 1998 to 2000. Phosphate concentration in the lower layer of Yodo River estuary was important to the variation in red tide species in the upper layer of Yodo River estuary. PMID:18513758

  13. 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 avian predators should prove useful in developing or assessing management actions to reduce losses of juvenile salmonid smolts that attempt to pass through the estuary on their seaward migration.

  14. 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 from tributaries and the Federal Dam to the ETM and harbor may be high for those years with extreme tributary high-flow events. ?? 2008 Coastal and Estuarine Research Federation.

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2013-09-01

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

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

    Science.gov (United States)

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

    2014-02-01

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

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

    Science.gov (United States)

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

    2016-03-01

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

  20. Some chemical characteristics of the River Pra Estuary in the Western region of Ghana

    Directory of Open Access Journals (Sweden)

    J.K. Tufuor

    2007-04-01

    Full Text Available This paper discusses the nutrients budget and transfers of mineral nutrients from land to the sea that influence significantly the biogeochemical process operating in the coastal ecosystem. Water samples were collected fortnightly from six sites in the estuary and analysed using standard methods of analyses. It was observed that the estuary is alkaline in nature and the alkalinity increases, in the lower reach of the river as it flowed into the sea. The estuary could be classified as a well-mixed estuary due to the vertical homogenous distribution of salinity. The inorganic nitrogen in the water body exists predominately in the form of nitrate (NO3-, as compared to concentrations of ammonium (NH4+ and nitrite (NO2-. The ranges of NO3-, NH4+ and NO2- concentrations are (4.98-8.27, (0.11-0.46 and (0.005-10.95 x 10-3 mg/L. The concentrations of nitrate, nitrite, ammonium and phosphate were found to be within WHO specification. The calculated residual flow (VR for both November and December are -2.7 x 107 m3 day-1 and -1.01 x 107 m3 day-1, respectively. The negative value of VR implies that water flows from the system. The corresponding residence and flush times are 324 and 109 seconds and 828 and 595.2 seconds for November and December, respectively.

  1. 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.

    2012-10-01

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

  2. Disposal of radioactive wastes into rivers, lakes and estuaries

    International Nuclear Information System (INIS)

    The purpose of this report is to present, in the light of the information and experience accumulated to date, those principles and practices which, if applied to the disposal of radioactive wastes into inland surface and estuarial waters will ensure that man will not experience radiation exposures that are above the limits recommended by the International Commission for Radiation Protection (ICRP); and further, that radiation exposures are kept as far below those limits as is practicable. Disposal into sub-surface waters has not been specifically considered as this topic has been covered in another International Atomic Energy Agency publication. The report discusses the mechanisms and parameters which affect and control the fate of radionuclides introduced into fresh waters; it discusses the concepts of ''critical nuclide'', ''critical pathway'' and ''critical population group'' and demonstrates how the use of these concepts provides a sound, convenient and economical means for setting discharge limits and maintaining a continuing surveillance. It offers practical advice on the use of these concepts; gives some detailed information on uptake and dispersion mechanisms; and offers instruction on how to use this information and these concepts to estimate potential radiation doses and thus establish discharge limits.

  3. Sediment accumulation rate and radiological characterisation of the sediment of Palmones River estuary (southern of Spain)

    International Nuclear Information System (INIS)

    Chemical analyses and radioecological methods were combined in order to estimate the sediment accumulation rate in the upper 20 cm depth of the Palmones River estuary. Organic matter, total carbon, C:N and 137Cs vertical profiles showed changes at 13 cm depth. These changes could be associated with the decrease in river input since 1987 when a dam situated in the upper part of the estuary started to store water. Using 1987 as reference to date the sediment, accumulation rate was 1.2 cm yr-1. As alternative method, two layer model of 210Pbxs vertical distribution showed a sedimentation rate of 0.7 cm yr-1 with a surface mixing layer of 7 cm thickness. The high ammonium, potassium and sodium content in pore water and the strong correlation between 137Cs activities and organic matter in dry sediment suggests that 137Cs (the only anthropogenic product detected) is mainly accumulated in the estuary associated with the particulate organic material from the catchment area

  4. Sediment accumulation rate and radiological characterisation of the sediment of Palmones River estuary (southern of Spain).

    Science.gov (United States)

    Rubio, L; Linares-Rueda, A; Dueñas, C; Fernández, M C; Clavero, V; Niell, F X; Fernández, J A

    2003-01-01

    Chemical analyses and radioecological methods were combined in order to estimate the sediment accumulation rate in the upper 20 cm depth of the Palmones River estuary. Organic matter, total carbon, C:N and (137)Cs vertical profiles showed changes at 13 cm depth. These changes could be associated with the decrease in river input since 1987 when a dam situated in the upper part of the estuary started to store water. Using 1987 as reference to date the sediment, accumulation rate was 1.2 cm yr(-1). As alternative method, two layer model of (210)Pb(xs) vertical distribution showed a sedimentation rate of 0.7 cm yr(-1) with a surface mixing layer of 7 cm thickness. The high ammonium, potassium and sodium content in pore water and the strong correlation between (137)Cs activities and organic matter in dry sediment suggests that (137)Cs (the only anthropogenic product detected) is mainly accumulated in the estuary associated with the particulate organic material from the catchment area. PMID:12573860

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

    Science.gov (United States)

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

    2016-02-01

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

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

    Science.gov (United States)

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

    2014-05-01

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

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

    Science.gov (United States)

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

    2012-12-01

    Nutrient loadings to urbanized estuaries have increased over the past decades in response to population growth and upgrading to secondary sewage treatment. Evidence from the San Francisco Estuary (SFE) indicates that increased ammonium (NH4) loads have resulted in reduced primary production, a counter-intuitive finding; the NH4 paradox. Phytoplankton uptake of nitrate (NO3), the largest pool of dissolved inorganic nitrogen, is necessary for blooms to occur in SFE. The relatively small pool of ambient NH4, by itself insufficient to support a bloom, prevents access to NO3 and bloom development. This has contributed to the current rarity of spring phytoplankton blooms in the northern SFE (Suisun Bay), in spite of high inorganic nutrient concentrations, improved water transparency and seasonally low biomass of bivalve grazers. The lack of blooms has likely contributed to deleterious bottom-up impacts on estuarine fish. This bloom suppression may also occur in other estuaries that receive large amounts of anthropogenic NH4. In 2010 two rare diatom blooms were observed in spring in Suisun Bay (followed by increased abundances of copepods and pelagic fish), and like the prior bloom observed in 2000, chlorophyll accumulated after NH4 concentrations were decreased. In 2010, low NH4 concentrations were apparently due to a combination of reduced NH4 discharge from a wastewater treatment plant and increased river flow. To understand the interactions of river flow, NH4 discharge and bloom initiation, a conceptual model was constructed with three criteria; 1) NH4 loading must not exceed the capacity of the phytoplankton to assimilate the inflow of NH4, 2) the NH4 concentration must be ?4 ?mol L-1 to enable phytoplankton NO3 uptake, 3) the dilution rate of phytoplankton biomass set by river flow must not exceed the phytoplankton growth rate to avoid "washout". These criteria were determined for Suisun Bay; with sufficient irradiance and present day discharge of 15 tons NH4-N d-1at the upstream wastewater treatment plant (WTP). The loading criterion requires phytoplankton NH4 uptake to exceed 1.58 mmol m-2 d-1; the concentration criterion requires river flow >800 m3 s-1 at the WTP for sufficient NH4 dilution and the washout criterion requires river flow at Suisun Bay river flow), could be used as a management tool to restore pre-existing productivity in the SFE and similarly impacted estuaries.

  8. 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.

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

    Science.gov (United States)

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

    2014-02-01

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

    Pakenham, A.; Wheatcroft, R.

    2008-12-01

    The transfer of sediment from source to sink involves a complex set of processes that vary over multiple time and space scales. In the Pacific Northwest, there is anecdotal evidence that many estuaries are filling rapidly with sediment due to changes in hydroclimatology coupled with land-use changes. Because both factors may co-exist, the relative contribution of each, the mechanisms of sediment delivery (event vs. steady), and the role of larger scale processes, such as sea level rise, are important issues to disentangle. To address these issues we are studying the Siletz River, a small (Cs-137 geochronology) collected within the estuary indicates, however, that there has not been a clear acceleration of sediment accumulation during the latter half of the 20-th century, and suggests extrabasinal effects (e.g., sea level rise, neotectonics) may control accumulation.

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

    Science.gov (United States)

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

    2016-02-01

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

  14. Nitrate sources and dynamics in the salinized rivers and estuaries – a ?15N- and ?18O-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 ?15N and ?18O-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–.

  15. Sciaenidae fish of the Caeté River estuary, Northern Brazil: mitochondrial DNA suggests explosive radiation for the Western Atlantic assemblage

    OpenAIRE

    Christina Vinson; Grazielle Gomes; Horacio Schneider; Iracilda Sampaio

    2004-01-01

    Sciaenids are fish which are normally abundant in tropical estuaries of the western Atlantic. Studies on the Caeté river estuary in the northern Brazilian state of Pará have revealed that in this area Sciaenidae is the dominant family, comprising almost 50% of all teleosts sampled. In this paper we present the results of the first phylogenetic study on South American estuarine sciaenids, during which we obtained mitochondrial gene 16S sequences from 15 species belonging to eight genera occurr...

  16. HIDRODYNAMIC CHARACTERIZATION OF THE CUBATÃO RIVER ESTUARY, JOINVILLE CARACTERIZAÇÃO HIDRODINÂMICA DO ESTUÁRIO DO RIO CUBATÃO, JOINVILLE.

    Directory of Open Access Journals (Sweden)

    C. A. SCHETTINI

    2000-12-01

    Full Text Available This paper presents a preliminary approach on the hydrodynamics of the Cubatão River estuary based on hydrographic data from a thirteen-hour campaign (a complete tidal cycle under spring tide condition. Current speed and direction, salinity, temperature and turbidity were recorded at 1.5 m bellow the water surface near the estuary mouth, with a moored acoustic currentmeter. Vertical profiles of salinity and temperature were done close to the mooring every hour with a CTD to give the vertical estuarine structure. Vertical profiles of CTD were also done along the estuary during the flood slack water. The results show that the Cubatão River estuary is vertically homogeneous almost time, with small periods with weak stratification during the ebb. The tidal regime was assimetric, with ebb currents stronger than flood currents. Este trabalho apresenta uma caracterização preliminar da hidrodinâmica do estuário do Rio Cubatão baseada em dados hidrográficos obtidos durante uma campanha de treze horas (um ciclo completo de maré em condições de maré de sizígia. Dados de velocidade e direção de corrente, salinidade, temperatura e turbidez foram obtidos à 1,5 m abaixo da superfície, próximo da desembocadura do estuário com o fundeio de um correntógrafo acústico. Perfis verticais de salinidade e temperatura foram realizados próximos ao fundeio a cada hora com um CTD para fornecer a estrutura vertical. Perfis de CTD também foram realizados ao longo do estuário durante a preamar. Os resultados mostram que o estuário do Rio Cubatão apresenta-se verticalmente homogêneo com períodos menores de estratificação durante a vazante. O regime de maré mostra uma assimetria acentuada, com correntes de vazante muito mais intensas do que as correntes de enchente.

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

    International Nuclear Information System (INIS)

    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. -- Highlights: •Antibiotics were ubiquitous in the river water and costal water in the Pearl River Delta. •Antibiotics exhibited distinct temporal and spatial trends in the riverine runoff outlets. •Annual outflows of antibiotics were 193 tons from the Pearl River to coastal ocean. •Some antibiotics posed high risks to some organisms in the PRD environments. -- Antibiotics were ubiquitous in the river and coastal water in the Pearl River Delta and posed various ecological risks to the relevant aquatic organisms

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

    Science.gov (United States)

    Pang, A. P.; Sun, T.

    2013-12-01

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

  19. 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 River Estuary changed rapidly in response to engineering works that forced the channel to self-deepen. Analysis of historical bathymetric data indicates that the channel lost an estimated 3 ?? 106 tons of sediment between ca. 1939 and 2002 (50,000 tons/yr average) by subaqueous erosion, increasing in depth by as much as 4 m in places. Erosion appears to have been concurrent with systematic bulkheading of the shoreline after ca. 1865, which decreased the estuary surface area by ??? 19% overall. Evidently, self-deepening of the channel is a morphodynamic adjustment to reestablish equilibrium cross-sectional area, yet the state of this change locally and elsewhere in the estuary is unknown. Subaqueous erosion documented in this study is a significant source of sediment with implications to the sediment budget and environmental quality of the Hudson River Estuary. ?? 2005 Elsevier B.V. All rights reserved.

  20. 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 outfall in the Messinian Gulf. A significant enrichment in phenolic content of sediments as well in organic carbon was observed in 2011 when compared to 2008, in most of the cases, indicating degradation of the study aquatic ecosystems of Messinia Prefecture.

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

    Science.gov (United States)

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

    2012-04-01

    1. The site Lagos is a city in western Algarve situated on the right margin of the Ribeira de Bensafrim. Its dissymmetric estuary has two hills: one that supports the town of Lagos and the hill of Monte Molião, known for its archaeological site. During the Late Iron Age the establishment was constrained to the top of that small hill Molião After that period, in Roman Age, people moved their location to the right river margin, founding what was then known as Laccobriga - Lagos. 2. Objectives and methodology The main objective of this study is to understand the possible causes for the abandonment of Monte Molião and what were the reasons behind the foundation of the roman city of Laccobriga? The data used were the results from the sedimentary analysis of cores in the alluvial plain of the Bensafrim valley, radiocarbon data, together with the previous excavation results and structure analysis. 3. First results: (i) In the sedimentary record, the rate sand/clay as well as several statistical parameters and shells, show different energetic environments. (ii) Radiocarbon data shows that the estuary remained open until 2800 cal BP, when a spit developed at the mouth of the estuary and a salt marsh begin to develop behind the sand barrier. (iii) Remnants of fishing activities since the Iron Age found in the archaeological site highlight different strategies for the establishment around the estuary. Archeological data tells us that, the Iron Age fishing was mainly fluvial, while later shellfish remains point that in the roman period fishing activities were made in open sea. (iv) The analyzed roman structures in the archaeological site of Monte Molião, show a clear sign of a violent seismic destruction probably related to the known 63 b.C. earthquake. 4. Conclusions (i) It is proven that in the river Bensafrim the estuary changed from an open estuary before 2800 cal BP to a closed one. This could have forced the change of the fishing habits of the populations that depended on that river. We also believe that this could have contributed to the foundation of the roman city of Lagos on the right river margin. (ii) The 63 b.C. earthquake was strong enough to alter the establishment strategy. Archaeological record shows us that in Monte Molião there was a period with no occupation between the second half of the first century b.C. and the beginning of the first century a.D.. (iii) This study not only highlights the importance of the estuary in the occupation History of Lagos city but also shows that this kind of multi-disciplinary investigations are fundamental to understand human establishment processes. Acknowledgements This research was funded by the research project, PTDC/CTE-GIX/104035/2008 - FMI 5000: Environmental changes: Fluvio-marine interactions over the last 5000 yrs, from Portuguese Science and Technology Foundation (FCT-MCTES).

  2. 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.

  3. Use of multitracers for the study of water mixing in the Paraiba do Sul River estuary

    International Nuclear Information System (INIS)

    Multitracers were used to study water mixing in the Paraiba do Sul River estuary region in August 2007 (dry season) and March 2008 (rainy season) and to evaluate the reach of the river plume in the direction of the open ocean. Two sampling campaigns were carried out, each in a different season. Based on these results, it was possible to conclude that the multitracers used in this study (salinity, Si, Ba and U, as well as the radium isotopes 223Ra, 224Ra, 226Ra and 228Ra) presented satisfactory results toward defining the plume reach and determining the residence time and water-mixing processes in the estuary. A strong correlation was observed between tracers and the distance to the coast. During the low river water discharge period, the riverine water took about 10 days to reach open ocean waters (salinity ? 35). During the rainy period this value decreased to 6 days. Based on the radium results, it was possible to calculate diffusion coefficients (Kh) of 23 km2 d-1 and 38 km2 d-1 for 224Ra and 223Ra, respectively, during the dry season (winter). Values of 65 km2 d-1 and 68 km2 d-1 for 223Ra and 224Ra, respectively, were found for the rainy period (summer).

  4. Use of multitracers for the study of water mixing in the Paraiba do Sul River estuary

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Thaisa Abreu, E-mail: abreu.thaisa@gmail.co [Departamento de Quimica, Pontificia Universidade Catolica, 22453-900 Rio de Janeiro, RJ (Brazil); Godoy, Jose Marcus [Departamento de Quimica, Pontificia Universidade Catolica, 22453-900 Rio de Janeiro, RJ (Brazil); Instituto de Radioprotecao e Dosimetria IRD/CNEN, 22780-160 Rio de Janeiro, RJ (Brazil); Godoy, Maria Luiza D.P. [Instituto de Radioprotecao e Dosimetria IRD/CNEN, 22780-160 Rio de Janeiro, RJ (Brazil); Moreira, Isabel [Departamento de Quimica, Pontificia Universidade Catolica, 22453-900 Rio de Janeiro, RJ (Brazil); Carvalho, Zenildo L. [Instituto de Radioprotecao e Dosimetria IRD/CNEN, 22780-160 Rio de Janeiro, RJ (Brazil); Salomao, Marcos Sarmet M.B.; Rezende, Carlos E. [Centro de Biociencias e Biotecnologia, Universidade Estadual do Norte Fluminense, 28013-600 Campos dos Goytacazes, RJ (Brazil)

    2010-07-15

    Multitracers were used to study water mixing in the Paraiba do Sul River estuary region in August 2007 (dry season) and March 2008 (rainy season) and to evaluate the reach of the river plume in the direction of the open ocean. Two sampling campaigns were carried out, each in a different season. Based on these results, it was possible to conclude that the multitracers used in this study (salinity, Si, Ba and U, as well as the radium isotopes {sup 223}Ra, {sup 224}Ra, {sup 226}Ra and {sup 228}Ra) presented satisfactory results toward defining the plume reach and determining the residence time and water-mixing processes in the estuary. A strong correlation was observed between tracers and the distance to the coast. During the low river water discharge period, the riverine water took about 10 days to reach open ocean waters (salinity {approx} 35). During the rainy period this value decreased to 6 days. Based on the radium results, it was possible to calculate diffusion coefficients (K{sub h}) of 23 km{sup 2} d{sup -1} and 38 km{sup 2} d{sup -1} for {sup 224}Ra and {sup 223}Ra, respectively, during the dry season (winter). Values of 65 km{sup 2} d{sup -1} and 68 km{sup 2} d{sup -1} for {sup 223}Ra and {sup 224}Ra, respectively, were found for the rainy period (summer).

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

    Science.gov (United States)

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

    2014-03-01

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

  6. Composition of Macrobenthos in the Wouri River Estuary Mangrove, Douala, Cameroon

    OpenAIRE

    Ngo-Massou, Vanessa Maxemilie; Koum, Guillaume Léopold Essome; Dina, Emmanuel Ngollo; Din, Ndongo

    2012-01-01

    The macrobenthos of mangroves is dominated by crabs and molluscs, which have a significant ecological role in terms of the structure and function of mangroves. The aim of this study was to determine the abundance and biological diversity of these groups in the Wouri River estuary mangrove in Douala, Cameroon. Three methods of crabs capture (excavation, sight harvest and visual count) were used in 10 × 10 m2 plots for the crabs and quadrats of 1 × 1 m2 were employed for mollusc counts. In all,...

  7. Cesium-137, metals and organic carbon in the sediments of the James River estuary, Virginia

    International Nuclear Information System (INIS)

    The concentrations of cesium 137, copper, lead, zinc and organic carbon in the sedimentary sub-environments found in a 10 km stretch of the the estuary of the James River, Virginia, were determined. Sedimentation rates in the different regions were estimated by cesium 137 geochronology and were found to vary from .4 to 3 cm/yr. Concentrations of cesium 137, lead, zinc, copper and carbon vary by a factor of 2 to 3 in surface sediments. Inventories for fine-grain sediments correlate well. Concentrations in coarse-grained sediments are considerably lower. (U.K.)

  8. Aquatic organism contamination by mercury residues in the Coatzacoalcos river estuary, Mexico

    International Nuclear Information System (INIS)

    Mercury residues in the biotic and abiotic elements of the Coatzacoalcos river estuary have been determined over a two-year period. Main attention was given to aquatic species considered as indicators of the accumulation of Hg in the sediments. The highest levels were found in sediments and benthonic organisms. Mercury in human blood and hair was measured in two groups. The first group, which was chosen from occupationally exposed workers, showed higher values than the second group of non-occupationally exposed persons. The neutron activation analysis and atomic absorption analysis methods are discussed and results are presented. (author)

  9. Some ecological studies of the lower Cape Fear River Estuary, ocean outfall, and Dutchman Creek, 1971

    International Nuclear Information System (INIS)

    A survey of the hydrography and biological components of the Cape Fear River Estuary and nearshore ocean off Oak Island was conducted. Species diversity indices were computed from nekton samples and phytoplankton, zooplankton, and benthos samples are being analysed. A computer program was developed whereby data were alphabetized by species, sorted by location, station, and date, and printed. Experiments were conducted to determine the Critical Thermal Maximum of shrimp. Measurements were made on water temperature, salinity, and dissolved oxygen from June through October. (U.S.)

  10. Plutonium and radiocesium in the water column of the Hudson River estuary

    Science.gov (United States)

    Linsalata, P.; Simpson, H. J.; Olsen, C. R.; Cohen, N.; Trier, R. M.

    1985-12-01

    Isotopes of plutonium (Pu), cesium (Cs), and cobalt (Co) introduced into the Hudson River Estuary from fallout deposition, the erosion of fallout-contaminated surface soils, and nuclear reactor effluent (isotopes of Cs and Co only) have been measured in water column samples collected from 1975 to 1980 Isotopic measurements conducted independently by two research groups utilizing different sampling and analytical techniques have been summarized. The major conclusions drawn from the work are that for water samples collected by the two laboratories over similar time periods, the mean concentrations of nonfilterable239,240Pu (radionuclides represents fractional mobilization rates on the order of 1 4 (×10-4) per year

  11. Activity of methane oxidizing bacteria along the River Elbe downstream to its estuary

    Science.gov (United States)

    Matoušu, A.; Šimek, K.; Bussmann, I.

    2012-04-01

    Contribution of rivers and estuarine systems to the global methane (CH4) budget is still not clear yet and for improving the estimations on the CH4 emission it is essential to cover the whole natural system in large-scale studies. In this context we quantified the activity of methane oxidizing bacteria (as a microbial "biofilter") over almost two seasons along a large European river system, the river Elbe, from its source in the Czech Republic towards to its estuary in the North Sea. Determination of methane oxidation rate was measured using a tritiated CH4 radiotracer technique. Methane concentrations in the water column were analyzed by the headspace method. The range of CH4concentrations and related microbial oxidation activities displayed a strong increase from the upper river parts, which includes mainly natural river, to the polluted downstream canalized parts of the river with high CH4concentrations and microbial activities, where anaerobic sediments occur. In the water column of the estuarine zone a sharp decrease of the CH4 concentration- and CH4 oxidation rates is mainly influenced by the increasing salinity. Additional parameters (temperature, dissolved oxygen, amount of suspended particular matter and nutrient content) are possible factors influencing the methanotrophic activity. Further investigations will compare the population structure of MOB at the different sites along the whole transect.

  12. Shoreline Change along Sheltered Coastlines: Insights from the Neuse River Estuary, NC, USA

    Directory of Open Access Journals (Sweden)

    J.P. Walsh

    2011-07-01

    Full Text Available Coastlines are constantly changing due to both natural and anthropogenic forces, and climate change and associated sea level rise will continue to reshape coasts in the future. Erosion is not only apparent along oceanfront areas; shoreline dynamics in sheltered water bodies have also gained greater attention. Additional estuarine shoreline studies are needed to better understand and protect coastal resources. This study uses a point-based approach to analyze estuarine shoreline change and associated parameters, including fetch, wave energy, elevation, and vegetation, in the Neuse River Estuary (NRE at two contrasting scales, Regional (whole estuary and Local (estuary partitioned into eight sections, based on orientation and exposure. With a mean shoreline-change rate of –0.58 m yr?1, the majority (93% of the NRE study area is eroding. Change rates show some variability related to the land-use land-cover classification of the shoreline. Although linear regression analysis at the Regional Scale did not find significant correlations between shoreline change and the parameters analyzed, trends were determined from Local Scale data. Specifically, erosion rates, fetch, and wave exposure increase in the down-estuary direction, while elevation follows the opposite trend. Linear regression analysis between mean fetch and mean shoreline-change rates at the Local Scale provide a first-order approach to predict shoreline-change rates. The general trends found in the Local Scale data highlight the presence of underlying spatial patterns in shoreline-change rates within a complex estuarine system, but Regional Scale analysis suggests shoreline composition also has an important influence.

  13. Analysis of thermal impact in tidal rivers and estuaries

    International Nuclear Information System (INIS)

    The paper presents a far field mathematical model for numerical simulation of transient one or two-dimensional thermal distributions in regions with severe reversing flow conditions. The Eulerian formulation employs the integral form of the conservation principles for mass and thermal energy. The two-dimensional (2 D) solution area is spanned by discrete elements of variable size and shape. The three-dimensional geometry of the flow region is accounted for by spatially intergrating over the enclosure surfaces of the discrete element. The derivation of the two-dimensional depth-averaged temperatur equations includes the constributions of the vertical variations of velocity and temperature. Surface heat transfer as well as turbulent effects are taken into account. Important mathematical and computational features of the model are summarized. There is a discussion of the four main algorithms, necessary to treat flow regions with complex shoreline geometries, viz. (i) specification of the boundary (ii) determination of all discrete element midpoints lying within the (possibly multiconnected) solution area (iii) construction of discrete elements of irregular geometry exactly matching the (curved) boundary, (iv) treatment of boundary condiditons and numerical solution of the resulting mathematical system of weakly coupled, ordinary differential equations derived from the conservation principles. Preliminary results of a computer simulation are compared with the available data for a section of the Lower Elbe river. The calculation of the two-dimensional temperature distribution includes existing power plants and industrial sites. (orig.)

  14. 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

    International Nuclear Information System (INIS)

    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

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

    Science.gov (United States)

    Li, Qiuhua; Chen, Lili; Chen, Fengfeng; Gao, Tingjin; Li, Xiaofeng; Liu, Songping; Li, Cunxiong

    2013-03-01

    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 81 taxa 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 33.45×106 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.

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

    Science.gov (United States)

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

    2015-06-01

    The objective of this study is to analyze the impact of hydrological variability influenced by climatic phenomena upon the sedimentary exchange between the turbidity maximum (TM) and a river mouth intertidal mudflat. This study, carried out over a period of 10 years (1997-2006) in the Seine Estuary (France), is specifically focused on two extreme periods: a wet one from 2001 to 2002 and a drier one from 2005 to 2006. This study is based on an original approach combining data gathered via low-altitude remote sensing with altimeter readings and ground-level measurements. During this 10 year period, we observed a link between climate change and the sedimentary processes on the mudflat surface. The modifications of sedimentary processes are mainly connected to the multiannual variability of hydrological flow rates that control the positioning of the turbidity maximum, the source of the sedimentary material deposited in this intertidal zone. The TM at the mouth of the Seine estuary is well developed; its maximum mass is estimated to be between 300,000 tons and 500,000 tons (Avoine et al., 1981) with maximum concentrations in the surface waters ranging from 1 to 2 g • l- 1 (Le Hir et al., 2001). Most of the fine particles stored within the TM have been found to originate from within the catchment area (Dupont et al., 1994). In the Seine estuary, the dynamics of the estuarine TM, in response to hydrodynamic forcings, have been previously described (Avoine et al., 1981) and modeled (e.g. Brenon and Le Hir, 1999; Le Hir et al., 2001). The TM is upstream of the northern mudflat when the river flow is low (< 450 m • s- 1) and nearby the study area when the river flow is higher. Thus during wet periods, the sedimentation rates increase by + 17 cm • y- 1, while during the drier one (when the turbidity maximum is located upstream of the estuary) we observed an erosion rate of 7.6 cm • y- 1. Sedimentation events in the mudflat resulting from spring tides are less frequent during dry periods, and they deposit a smaller quantity of sediment (- 23% of total deposition mass per event). Because of the lower flow rates coupled with the impacts of local development, the flood tides have become dominant. This contributes to the addition of sandy or silty sediments on the mudflat, of which the slope has increased 450% over 8 years caused by erosion.

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

    Science.gov (United States)

    Demina, L. L.

    2014-12-01

    Behavior of some trace metals (Al, As, Cd, Co, Cr, Cu, Fe, Mn, Ni and Pb) in water column (soluble metals' concentrations (µg/l) in water of the two estuaries. With salinity increase along transects Fe susp., Mn susp. and Zn susp. decreased by a factor of 100-500, that has led to a growth of a relative portion of dissolved trace metals followed by their bioaccumulation (Demina et al., 2010). A strong direct correlation between suspended Cu, Fe and SPM mass concentration was found. For the first time along the Yenisei River' Estuary -the Kara Sea transect a direct positive correlation between Cu suspended and volume concentration of SPM (mg/ml3) was found, that was attributed to contribution of phytoplankton aggregates in the SPM composition. A trend of relationship between content of suspended As and pelitic fraction (2-10 µm) of SPM was firstly found in theses basins also. Study of trace metal speciation in the bottom sediments (adsorbed, associated with Fe-Mn (oxyhydr)oxides, organic matter and fixed in the mineral lattice or refractory) has revealed the refractory fraction to be prevailing (70-95% total content) for Fe, Zn, Cu, Co, Ni, Cr, Cd and Pb. That means that toxic heavy metals were not available for bottom fauna. Mn was predominantly found in the adsorbed and (oxyhydr)oxides geochemically labile forms, reflecting the redox condition change along both transects and within the sedimentary cores. References. Demina L.L., Gordeev V.V., Galkin S.V., Kravchishina M.D. Biogeochemistry of some heavy metals and metalloids along the transect the Ob River Estuary - the Kara Sea. Oceanology, 2010, vo. 50, No 5, pp. 729- 742.

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

    International Nuclear Information System (INIS)

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

  19. Variability of Organic Carbon Content in Bottom Sediment of Pahang River Estuary, Pahang, Malaysia

    Directory of Open Access Journals (Sweden)

    B.Y. Kamaruzzaman

    2009-01-01

    Full Text Available The percentage organic carbon content of 62 bottom estuarine sediment in Pahang river estuary were analyzed using the wet dichromate oxidation method. In this study, the organic carbon distribution ranged from 0.09 to 2.05%. The high concentration can be found near the Pahang river mouth while the low concentration occurred at upstream. The sediment particle size at the same transects were also measured with the dry sieving and laser diffraction method. The average concentration of organic carbon was 0.88% while the average grain size was 2.44 ?. In this study, the carbon organic showed a significant relationship with the mean size (p<0.05 with the organic carbon content increase with the increase of mean size values.

  20. 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).

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

    Science.gov (United States)

    Pang, Aiping; Sun, Tao; Yang, Zhifeng

    2013-03-01

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

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

    International Nuclear Information System (INIS)

    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 ?g/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 of several Baltic Sea estuaries. • More information is needed on low salinity estuaries

  3. 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...

  4. 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...

  5. Evaluation of the Level of Organochlorinated Pesticides Contamination in Environment of the Red River and its Balat Estuary

    International Nuclear Information System (INIS)

    The pollution level of OC pesticides such as Lindane, DDT and its metabolites contaminants in water, sediments and Biota collected along the Red River and from the Balat estuary have, for the first time in the North of Vietnam, been determined by GC technique using capillary columns and electron capture detection (ECD). The concentration of DDT and DDE was found to be up to 38.4 ppb and 27.3 ppb, respectively, in sediments from the Red River and its Balat estuary. Lindane residue in Red River's and Balat estuary's sediments was found at level of 1.3-4.2 and 14.6-52.6 ppb, respectively. In water Lindane contaminant was detected in the sample collected from the estuarine area only, while DDE was found in both River and estuarine water. Residue of Lindane in mussel flesh was found to be always higher (up to 145 ppb) than that of any DDT's metabolites, e.g. the highest value of DDE contaminant is 66 ppb. The finding shows that Lindane contamination in marine environmental samples from the Balat estuary is higher as compared with those from the Mediterranean Sea but DDT's ones are at the same level. (author). 8 refs., 6 tabs., 1 map

  6. Foraminifera in surface sediments of Mandovi River Estuary: Indicators for mining pollution and high sea stand in Goa, India

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.; Panchang, R.; Banerjee, P.

    , probably due to mining activities in the catchment area of the Mandovi River estuary, is suggested as the plausible reason for the decline of fauna. An intriguing finding of the present study is the presence of substantial amount of reworked/older specimens...

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

    Science.gov (United States)

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

    2015-07-21

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

  8. Coastline Change Surround Sekampung River Estuary Estimated by Geographic Information System Technique

    Directory of Open Access Journals (Sweden)

    Fahri

    2011-05-01

    Full Text Available Surround a big river estuary coastline has a dynamic characteristic and change along a period of time, because of a natural process and/or it is accelerated by human activities. The surround Sekampung river estuary coastline located in Rawa Sragi area is one of the most dynamic coastlines in southern Lampung Province that has changed significantly from 1959 (as a natural process to year 1987 (as an accelerated process by human activities since the government of Indonesia has applied swamp drainage system for Rawa Sragi area. It is likely that the coastline has changed significantly in the period of 1987 to 2009 (as an increasing intensity of the human activities in the surrounding Rawa Sragi land. The objective of this research was to analyze the coastline change in the surrounding of Sekampung river estuary in two periods of time: (1 the change of the 1959 – 1987 period coastlines; and (2 the change of the 1987 – 2009 period coastlines. The method of this research was a GIS technique, the implementation was divided into three main steps: (1 the first analysis was conducted in laboratory include raster data source analysis and registration, coastline digitations, and overlaying and analysis of the coastline data; (2 field observation (ground check was conducted to observe and verify the ground existing coastline; and (3 the last analysis was conducted after ground check activity to improve and to verify the first coastline analysis results. The result of this research indicated that coastline change in the period of 1959 to 1987 increased the coast land as much as 717.19 hectares, but decreased the coast land as much as 308.51 hectares. Furthermore the coastline change in the period of 1987 to 2009 increased the coast land as much as 162.504 hectares, but decreased the coast land as much as 492.734 hectares. The 1959 – 1987 coastline change was a coast land increasing period, but the 1987 – 2009 coastline change was a coast land decreasing period.

  9. Evaluating Cumulative Ecosystem Response to Restoration Projects in the Lower Columbia River and Estuary, 2008

    International Nuclear Information System (INIS)

    Draft annual report for the Cumulative Effects Study for the US Army Corps of Engineers, Portland District. This is the fifth annual report of a seven-year project (2004 through 2010) to evaluate the cumulative effects of habitat restoration actions in the 235-km-long Columbia River estuary. The project, called the Cumulative Effects Study, is being conducted for the U.S. Army Corps of Engineers, Portland District (CENWP), 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), and the Columbia River Estuary Study Taskforce (CREST). 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 lower Columbia River and estuary (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 2008, annual field research involved intensive, comparative studies paired by habitat type (tidal swamp versus marsh), trajectory (restoration versus reference site), and restoration action (tide gate versus culvert versus dike breach). During 2008, the specific objectives for the Cumulative Effects Study were to do the following: (1) Summarize the adaptive management framework for LCRE habitat restoration activities; (2) Finalize the levels-of-evidence approach and ecological theory underpinning the analysis, synthesis, and evaluation of the cumulative effects of multiple habitat restoration projects in the LCRE; (3) Summarize new results from analyses from 2005-2008 project research for the purpose of cumulative effects evaluation in the LCRE; (4) Initiate a synthesis and evaluation of cumulative effects in the LCRE; (5) Assess management implications, lessons learned, decision-making, 2009-2010 research, and final project deliverables; and (6) Provide a hydrodynamic model assessment of synergistic effects, analysis summaries of the additive modeling pilot study, natural breach and habitat creation sites, wetted area, hydrology and fish, monitoring summaries for Julia Butler Hanson Wildlife Refuge and Crims Island, and a preliminary meta-analysis of effectiveness monitoring data.

  10. Report on the workshop examining the potential effects of hydroelectric development on Beluga of the Nelson River Estuary, Winnipeg, Manitoba, November 6 and 7, 1990

    International Nuclear Information System (INIS)

    A summary is presented of discussions and conclusions at a workshop held to examine the potential effects of hydroelectric development on beluga whales of the Nelson River estuary in Manitoba. Background information is provided on the estuary, beluga whales and their use of arctic and subarctic estuaries, and hydroelectric development on the Nelson River. Potential impacts of such development on the whales are reviewed in the categories of direct effects of changes in physical-chemical conditions (temperature and discharge), indirect effects of disturbances mediated through the food chain, and effects on socioeconomic conditions that may affect beluga whales. Since the biology of beluga whales and other phenomena of interest in this study are poorly known, recommendations are made for research and monitoring activities in the Nelson River estuary. In general, the workshop participants felt that changes in the estuary due to hydroelectric development would not be large enough to affect beluga whales strongly. 34 refs., 1 fig

  11. Report on the workshop examining the potential effects of hydroelectric development on Beluga of the Nelson River Estuary, Winnipeg, Manitoba, November 6 and 7, 1990

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence, M.J.; Paterson, M.; Baker, R.F.; Schmidt, R.

    1992-01-01

    A summary is presented of discussions and conclusions at a workshop held to examine the potential effects of hydroelectric development on beluga whales of the Nelson River estuary in Manitoba. Background information is provided on the estuary, beluga whales and their use of arctic and subarctic estuaries, and hydroelectric development on the Nelson River. Potential impacts of such development on the whales are reviewed in the categories of direct effects of changes in physical-chemical conditions (temperature and discharge), indirect effects of disturbances mediated through the food chain, and effects on socioeconomic conditions that may affect beluga whales. Since the biology of beluga whales and other phenomena of interest in this study are poorly known, recommendations are made for research and monitoring activities in the Nelson River estuary. In general, the workshop participants felt that changes in the estuary due to hydroelectric development would not be large enough to affect beluga whales strongly. 34 refs., 1 fig.

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

    Science.gov (United States)

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

    2014-02-01

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

  13. Assessing pollution trends in the Guadalquivir River estuary using N-way analysis

    Directory of Open Access Journals (Sweden)

    López-López J. A.

    2013-04-01

    Full Text Available Human activities have contributed to a deployment of environmental quality. In the last decades the problem of water preservation has gained increasing attention, and new policies have been developed for water resources remediation. Statistical techniques for data treatment are based on the organization of data in a bi-dimensional array; thus, some shades on the trend of the distribution tend to be ignored. Multiway techniques, where data are gathered in n directions, allow the analysis of the results through different directions at the same time. In particular, for 3MPCA a principal components analysis is conducted using three modes and a “core” matrix that allows assessing their interactions. The Guadalquivir River estuary has been used as a model system for the application of 3MPCA in the study of long term evolution of pollutants. Nutrients and heavy metals ultra-traces level have been used to characterize the estuary. The 3MPCA was used to assess the relationships within chemical variables, sampling stations and sampling campaigns.

  14. Metals and acid volatile sulfide in sediment cores from the Sergipe River Estuary, Northeast, Brazil

    Scientific Electronic Library Online (English)

    José do Patrocínio H., Alves; Elisângela de Andrade, Passos; Carlos A. B., Garcia.

    Full Text Available Foram estudados o sulfeto volatilizado em meio ácido (AVS), os metais simultaneamente extraídos (SEM) e os metais em sítios de sedimentos do Estuário do Rio Sergipe, Brasil. As concentrações de AVS e SEM foram, em geral, maiores nos sedimentos dos sítios situados nas áreas que recebem maior aporte a [...] ntrópico devido à poluição urbana. Nesses sítios, o sulfeto parece ser a principal fase de ligação para os metais. No sítio do sedimento situado na área de maior influência marinha, as fases mais importantes de ligação para os metais parecem estar associadas à matéria orgânica e aos carbonatos. Os perfis de AVS permitiram identificar dois tipos de processos de sedimentação no estuário. Em todos os sítios, as relações SEM/AVS foram muito menores do que 1. Abstract in english Acid volatile sulfide (AVS), simultaneously extracted metals (SEM) and metals were studied in sediment cores from the Sergipe River Estuary, Brazil. AVS and SEM concentrations were, in general, higher in the core sediments from areas which receive a higher anthropic contribution due to urban polluti [...] on. In these cores, the sulfide seemed to be the main connection for the metals. In the core obtained from the area of major marine influence, the most important binding phases for the metals seemed to be associated with organic matter and carbonates. The AVS profiles allow identification of two types of sedimentation processes in the estuary. In all cores SEM/AVS ratios were much lower than 1.

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

    Science.gov (United States)

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

    2015-01-01

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

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Science.gov (United States)

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

    2015-06-01

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

  18. Characterization of dissolved organic matter in the Piauí river estuary, Northeast Brazil

    Scientific Electronic Library Online (English)

    Adnivia Santos, Costa; Elisangela de Andrade, Passos; Carlos A. B., Garcia; José do Patrocinio H., Alves.

    2011-11-01

    Full Text Available A espectroscopia de fluorescência e o carbono orgânico dissolvido (COD) foram utilizados para caracterização da matéria orgânica dissolvida (MOD) no estuário do Rio Piauí, um estuário tropical situado no Estado de Sergipe, nordeste do Brasil. As intensidades de fluorescência foram maiores no período [...] chuvoso e menores no período seco, evidenciando que a variabilidade das propriedades fluorescentes da MOD é ditada, principalmente, pela descarga fluvial e pelo processo de diluição no estuário. No período chuvoso, os compostos tipo triptofano e húmicos predominaram na composição da MOD, enquanto no período seco ocorreu um aumento significativo dos constituintes tipo proteínas. As relações das intensidades de fluorescência com a salinidade sugerem um comportamento não conservativo para a MOD fluorescente. O COD mostrou um comportamento conservativo no período seco e não conservativo no período chuvoso, com produção de COD na parte superior do estuário. A complexação da MOD com o Cu(II), estudada usando a técnica de supressão da fluorescência, evidenciou o potencial de complexação dos fluoróforos tipo proteínas, tripofano e húmico. Abstract in english Fluorescence spectroscopy and dissolved organic carbon (DOC) measurements were used to characterize the dissolved organic matter (DOM) in the Piauí River estuary, a tropical estuary situated in the State of Sergipe, Northeast Brazil. Fluorescence intensities were greater during the rainy period than [...] the dry period, demonstrating that variability in the fluorescence properties of the DOM was determined mainly by the fluvial discharge and the dilution processes occurring in the estuary. During the rainy period, tryptophan-like and humic substances were the main components of the DOM, while during the dry period there was a significant increase of protein-like constituents. Relationships identified between fluorescence intensities and salinity were indicative of non-conservative behavior of the fluorescent DOM. DOC showed behavior that was conservative during the dry period, and non-conservative during the rainy period, with production of DOC in the upper reaches of the estuary. The complexation of DOM with Cu(II), studied using the fluorescence suppression technique, showed the complexation potentials of protein, tryptophan and humic type fluorophores.

  19. Seeking a Chemical Signature for Flood Deposits, Neuse River Estuary, North Carolina

    Science.gov (United States)

    Benninger, L. K.; Wells, J. T.

    2004-05-01

    Major flooding in eastern North Carolina during September-November 1999 caused substantial sediment redistribution in the Neuse River estuary. Locations showing both net erosion and net deposition have been identified by comparing profiles of excess 210-Pb and fallout 137-Cs in cores collected before and after the flooding. While these radionuclide tracers are well suited to studies of modern flooding, however, their half-lives and input histories limit their utility to the last 50-100 years. Thus we have sought a chemical signature which might identify flood-derived sediments in older deposits. The 1999 floods did not leave coarse sediments in the thalweg of the Neuse estuary. The only texturally distinctive flood deposits were thin (estuary, however, the top 6 cm of a core was red in color when collected in November 1999. This gives a minimum of 6 cm flood deposition at this site; 137-Cs maxima before and after flooding suggest net flood deposition of 10-16 cm. Sediment samples from this core, and from a pre-flood (1988) core from the same location have been analyzed for a suite a major, minor, and trace elements. Elemental concentrations in both cores were normalized to aluminum to account for lithologic variations. The post-flood core-top has lower Si/Al, Mg/Al, and Ca/Al than the pre-flood core-top, suggesting that the flood deposits contain less quartz and calcium carbonate than pre-flood sediments. Fe/Al is distinctly higher in the post-flood core-top, but in time diagenesis may erase this signal. For many elements M/Al ratios do not differ systematically between pre-flood and post-flood cores (e.g., M = Cr, Ni, Zr, La, Ce, Th). Cu/Al, Zn/Al and Pb/Al vary between pre-flood and post-flood cores, but because of pollution inputs of Cu, Zn, and Pb these signals probably have little utility in pre-colonial sediments. Given present data the most promising candidates as tracers of flood deposits in the Neuse estuary appear to be Nb/Al and U/Al, both of which are elevated in post-flood core-tops; the U/Al signal may be compromised by estuarine U chemistry in older deposits.

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

    Science.gov (United States)

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

    2012-05-01

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

  1. Geochemical Proxy of Some Chemical Elements in Sediments of Kemaman River Estuary, Terengganu, Malaysia

    International Nuclear Information System (INIS)

    The concentrations of heavy metals (Mn, Co, Cu and Cr) were determined in the surface sediments from Kemaman River estuary using Inductively Coupled Plasma - Mass Spectrometry (ICP-MS). The relationship of heavy metal content with sediment particles size was studied. The average concentration of heavy metals are 597.8 ?g/g dry weight, 16.0 ?g/g dry weigh, 48.8 ?g/g dry weight and 100.4 ?g/g dry weight for Mn, Co, Cu and Cr, respectively. All metals showed low Enrichment Factor (EF) values (EF<1) when compared with Al which indicates that the elements in the sediment originated predominantly from crustal material or terigenous in origin. This study shows that there is a positive correlation between the mean particle size and the studied elements. (author)

  2. The biogeochemistry of photosynthetic pigments in the Jiulong River estuary and Western Xiamen Bay

    Science.gov (United States)

    Xu, Li; Hong, Hua-Sheng; Wang, Hai-Li; Chen, Wei-Qi

    2001-06-01

    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 dominnated 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.

  3. The hydrokinetic power resource in a macrotidal estuary: the Kennebec River of the central Maine coast

    Science.gov (United States)

    Brooks, D. A.

    2012-12-01

    Power levels available from the kinetic energy of tidal flows can be significant in coastal or estuarine regions with relatively modest tidal ranges. For example, the central Maine coast, where the mean semidiurnal tidal range is about 3 m, includes several river estuaries with narrow interconnecting passages where tidal currents exceed 2 m s-1. A numerical circulation model applied to this region shows that the vigorous tidal flows lead to available power peaks exceeding 3 Kw per square meter of turbine aperture in several sites during a spring tide. At one promising location, the peak power density is 6.5 Kw/m2 near the surface and the energy capacity in a 500 m2 section under mean tidal conditions is about 2700 Mwh per year, sufficient to meet the average consumption needs of about 150 homes connected to an electrical grid capable of accepting the tidal power pulses and blending them with traditional sources.

  4. 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.

  5. Plutonium and cesium radionuclides in sediments of the Savannah River Estuary

    International Nuclear Information System (INIS)

    A study was made of the 239Pu, 240Pu, 238Pu and 137Cs concentrations in tidal marsh sediments of the Savannah River estuary. Tidal marshes are identified as special locations for plutonium deposition because of the high biological productivity and relative stability of sediments as compared to channel sediments. The sup(239,240)Pu deposition averaged 3.2 mCi km-2 which is higher than land-based fallout values of about 2 mCi km-2. The sup(239,240)Pu to 137Cs ratio was about three times higher than fallout deposition estimates, indicating a more rapid desorption of 137Cs from sediment in the saline waters of the area. (author)

  6. Plutonium and cesium radionuclides in sediments of the Savannah River estuary

    Science.gov (United States)

    Hayes, David W.; Sackett, William M.

    1987-08-01

    A study was made of the 239Pu, 240Pu, 238Pu and 137Cs concentrations in tidal marsh sediments of the Savannah River estuary. Tidal marshes are identified as special locations for plutonium deposition because of the high biological productivity and relative stability of sediments as compared to channel sediments. The 239,240Pu deposition averaged 3·2 mCi km -2, which is higher than land-based fallout values of about 2 mCi km -2. The 239,240Pu to 137Cs ratio was about three times higher than fallout deposition estimates, indicating a more rapid desorption of 137Cs from sediment in the saline waters of the area.

  7. pCO2 distributions and air-water CO2 fluxes in the Columbia River estuary

    Science.gov (United States)

    Evans, Wiley; Hales, Burke; Strutton, Peter G.

    2013-01-01

    Sources of time and space variability in the distributions of surface water carbon dioxide partial pressure (pCO2) and air-water CO2 flux were quantified in the Columbia River estuary (CRE) during five cruises in spring, summer and autumn 2007/08. The CRE is an upwelling margin river-dominated mesotidal system that is an estuary class not represented in global flux compilations. Data from the CRE show instances of pCO2 under and oversaturation with respect to the atmosphere during every season in association with tidal, wind, biological and storm-driven sources of variability. On average the CRE is a sink for atmospheric CO2 during spring and a source during summer and autumn, with large positive air-water CO2 fluxes during the snowmelt freshet coinciding with the functional transition in the estuary. It is hypothesized here that interannual variability in size of the snowmelt freshet largely influences the extent of springtime CO2 uptake in the CRE, and subsequently the magnitude of net annual CO2 emission from the estuary. Data collected during an autumn storm show that large fluxes can drop quickly, even in the presence of high gas transfer velocities, because of rapid CO2 exchange with the atmosphere in this weakly buffered system. Combining seasonal observations of CO2 exchange with an assumption of winter conditions, we estimate that the net annual emission from the CRE is approximately 1 mol C m-2 yr-1. The air-water CO2 fluxes reported here are the first from an upwelling margin river-dominated mesotidal estuary, and the estimate of net annual exchange is substantially lower than those from other tidal and/or large river systems represented in global flux compilations.

  8. Changes in archaeal abundance and community structure along a salinity gradient in the lower Pearl River and its estuary

    Science.gov (United States)

    Zhang, C.; Wang, J.; Xie, W.; Wang, P.; Wei, Y.; Chen, S.; Zhou, X.

    2013-12-01

    Archaea occur in a wide range of habitats and across broad environmental gradients. At the global scale, salinity is known to be a major driving force for archaeal species diversity. The goal of this study was to examine changes in abundance and diversity of archaeal community DNA and membrane lipids in the water column along a salinity gradient in the lower Pearl River and estuary in the context of water/gas chemistry (pH, nitrate/nitrite, ammonia, methane, carbon dioxide). The pH increased and nitrate/nitrite and ammonia decreased from the lower Pearl River to the estuary. Methane and carbon dioxide fluxes were high in the lower Pearl River and decreased sharply in the estuary and toward the open ocean. The archaeal lipid profile exhibited abrupt changes from dominance of GDGT-0 (a glycerol diakly glycerol tetraether with zero cyclopentyl ring, which is commonly present in methanogens) to dominance of crenarchaeol (a specific biomarker for Thaumarchaeota) with increasing salinity from zero in the lower Pearl River to >0.5% in the estuary. Quantification of the 16S rRNA gene abundance using qPCR revealed a switch from bacteria-dominance to archaea-dominance and the ratio of archaeal nirK/bacterial-amoA genes had a peak value in the estuary, suggesting enhanced activity of ammonia oxidation by archaea. Pyrosequencing of archaeal 16S rRNA, amoA and nirK genes exhibited systematic variation defined by habitat types. Our current studies employ rate measurements of carbon fixation, ammonia oxidation, and nitrate reduction using isotope labeling approaches, which will allow us to link changes in archaeal community structure and ecological function.

  9. 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.

  10. Combined Stable Carbon Isotope and C/N Ratios as Indicators of Source and Fate of Organic Matter in the Bangpakong River Estuary, Thailand

    OpenAIRE

    Thanomsak Boonphakdee

    2008-01-01

    Stable carbon isotopes and C/N ratios of particulate organic matter (POM) in suspended solids and surficial sediment were used to define the spatial and temporal variability in an anthropogenic tropical river estuary, the Bangpakong River Estuary. Samples were taken along salinity gradients during the four different river discharges in the beginning, high river discharge and at the end of the wet season, and low river discharge during the dry season. The values of [C/N]a ratio and d13C in the...

  11. 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

    The ability of water-resource managers to adapt to future climatic change is especially challenging in coastal regions of the world. The East Coast of the United States falls into this category given the high number of people living along the Atlantic seaboard and the added strain on resources as populations continue to increase, particularly in the Southeast. Increased temperatures, changes in regional precipitation regimes, and potential increased sea level may have a great impact on existing hydrological systems in the region. The Savannah River originates at the confluence of the Seneca and Tugaloo Rivers, near Hartwell, Ga., and forms the state boundary between South Carolina and Georgia. The J. Strom Thurmond Dam and Lake, located 238 miles upstream from the Atlantic Ocean, is responsible for most of the flow regulation that affects the Savannah River from Augusta, Ga., to the coast. The Savannah Harbor experiences semi-diurnal tides of two low and two high tides in a 24.8-hour period with pronounced differences in tidal range between neap and spring tides occurring on a 14-day and 28-day lunar cycle. Salinity intrusion results from the interaction of three principal forces - streamflow, mean tidal water levels, and tidal range. To analyze, model, and simulate hydrodynamic behaviors at critical coastal streamgages in the Lower Savannah River Estuary, data-mining techniques were applied to over 15 years of hourly streamflow, coastal water-quality, and water-level data. Artificial neural network (ANN) models were trained to learn the variable interactions that cause salinity intrusions. Streamflow data from the 9,850 square-mile Savannah River Basin were input into the model as time-delayed variables. Tidal inputs to the models were obtained by decomposing tidal water-level data into a “periodic” signal of tidal range and a “chaotic” signal of mean water levels. The ANN models were able to convincingly reproduce historical behaviors and generate 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.

  12. Combined Stable Carbon Isotope and C/N Ratios as Indicators of Source and Fate of Organic Matter in the Bang Pa kong River Estuary, Thailand

    International Nuclear Information System (INIS)

    Full text: Stable carbon isotopes and C/N ratios of particulate organic matter (POM) in suspended solids and surficial sediment were used to define the spatial and temporal variability in an anthropogenic tropical river estuary, the Bang Pa kong River Estuary. Samples were taken along salinity gradients during the four different river discharges in the beginning, high river discharge and at the end of the wet season, and low river discharge during the dry season. The values of [C/N]a ratio and d13C in the river estuary revealed significant differences from those of the offshore station. Conservative behaviors of [C/N]a and d13C in the estuary during the wet season indicated major contribution of terrigenous C3 plants derived OM. By contrast, during the dry season, marine input mainly dominated OM contribution with an evidence of anthropogenic input to the estuary. These compositions of the bulk sedimentary OM were dominated by paddy rice soils and marine derived OM during the wet and dry seasons, respectively. These results show that the combined stable carbon isotopes and C/N ratios can be used to identify the source and fate of OM even in a river estuary. This tool will be useful to achieve sustainable management in coastal zone

  13. Combined Stable Carbon Isotope and C/N Ratios as Indicators of Source and Fate of Organic Matter in the Bangpakong River Estuary, Thailand

    Directory of Open Access Journals (Sweden)

    Thanomsak Boonphakdee

    2008-01-01

    Full Text Available Stable carbon isotopes and C/N ratios of particulate organic matter (POM in suspended solids and surficial sediment were used to define the spatial and temporal variability in an anthropogenic tropical river estuary, the Bangpakong River Estuary. Samples were taken along salinity gradients during the four different river discharges in the beginning, high river discharge and at the end of the wet season, and low river discharge during the dry season. The values of [C/N]a ratio and d13C in the river estuary revealed significant differences from those of the offshore station. Conservative behaviors of [C/N]a and d13C in the estuary during the wet season indicated major contribution of terrigenous C3 plants derived OM. By contrast, during the dry season, marine input mainly dominated OM contribution with an evidence of anthropogenic input to the estuary. These compositions of the bulk sedimentary OM were dominated by paddy rice soils and marine derived OM during the wet and dry seasons, respectively. These results show that the combined stable carbon isotopes and C/N ratios can be used to identify the source and fate of OM even in a river estuary. This tool will be useful to achieve sustainable management in coastal zone.

  14. 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 ?m-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 200?m 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 setembro e novembro/2003. O maior número de organismos foi encontrado em setembro/2003, no transecto do rio Muriá. A presença de C. longispinosum nas amostras obtidas durante setembro e novembro/2003 poderia estar provavelmente relacionada ao período reprodutivo desta espécie no estuário estudado, o qual está diretamente relacionado ao período seco na região. Os mais elevados valores de salinidade, bem como os elevados números de indivíduos observados no mês de setembro/2003 confirmam a suposição anterior, visto que nenhum indivíduo de C. longispinosum foi registrado durante os meses que incluem o período chuvoso (janeiro a junho.

  15. Occurrence of Cymbasoma longispinosum Bourne, 1890 (Copepoda: Monstrilloida) in the Curuçá River estuary (Amazon Littoral)

    Scientific Electronic Library Online (English)

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

    2010-09-01

    Full Text Available 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 Curuç [...] á) 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 200?m 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 setembro e novembro/2003. O maior número de organismos foi encontrado em setembro/2003, no transecto do rio Muriá. A presença de C. longispinosum nas amostras obtidas durante setembro e novembro/2003 poderia estar provavelmente relacionada ao período reprodutivo desta espécie no estuário estudado, o qual está diretamente relacionado ao período seco na região. Os mais elevados valores de salinidade, bem como os elevados números de indivíduos observados no mês de setembro/2003 confirmam a suposição anterior, visto que nenhum indivíduo de C. longispinosum foi registrado durante os meses que incluem o período chuvoso (janeiro a junho). Abstract in english 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 Cu [...] ruçá estuary (Pará, North Brazil). Samples were collected during neap tides via gentle (1 to 1.5 knots) 200 ?m-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).

  16. Macrobenthos from unvegetated intertidal areas in the Caeté river estuary in Bragança, Pará

    Directory of Open Access Journals (Sweden)

    José Souto Rosa Filho

    2006-12-01

    Full Text Available The macrobenthic community structure was studied in inter-tidal, non-vegetated areas of the Caeté river estuary, Pará, Brazil, during the dry season of 2003. Four samples were collected at four stations on the downstream direction (P1 to P4 using a corer (0.008 m2 and 20 cm long. Samples were sieved through a 0,3 mm mesh and the organisms preserved in a 5% formaline saline solution stained with Bengal rose. At each station, sediment samples were collected and salinity and water temperature recorded. A total of 105,500 individuals were collected, divided in 17 taxa comprising the fphyla: Nemertea, Arthropoda and Annelida. Polychaeta dominated the assemblages (11 taxa and 87.25% of the individuals. The most abundant taxa were Mediomastuscalifornienses, Nephtys Huviatilisand Oligochaeta (Tubificidae. Density and richness values varied from 2625 ind.m-2 and 3 taxa at station P1 to 96625 ind.m-2 among 16 taxa at station P4. Cluster analysis seperated three groups (50% similarity: Group 1, including samples from stations P3 and P4, was characterized by a relatively high salinity (22.6 to 26.5 and a fine sand substrate. This group, dominated by Sigambra grubii, was the richest (13 taxa, most diverse (?H´ = 1.18 and abundant (?= 12220 ind.m-2; Group 2, including samples from station P1, was characterized by a salinity of 5,1 and a silt-sandy substrate. This group presented the lowest richness (3 taxa, diversity (?H´ = 0.67 and abundance (?= 665 ind.m-2 values, and was dominated by the species Namalicastysabiuma; and Group 3, including samples from station P2, was characterized by a salinity of 3.6 and a silt-sandy substrate. N. abiuma was the most abundant species of this group that was characterized by intermediate richness (5 taxa, abundance (?= 2010 ind.m-2 and diversity (?H´ = 0.71 values. Thus, it is concluded that in the inter-tidal area of the non-vegetated Caeté river the species number is low; Annelida is the most abundant group; the species composition reflects the estuary salinity gradient; and richness, diversity and abundance increase from the upper to the lower estuary.

  17. Effects of intratidal and tidal range variability on circulation and salinity structure in the Cape Fear River Estuary, North Carolina

    Science.gov (United States)

    Becker, May Ling; Luettich, Richard A.; Seim, Harvey

    2009-04-01

    Tidal influences on circulation and the salinity structure are investigated in the largely unstudied Cape Fear River Estuary (CFRE), North Carolina, a partially mixed estuary along the southeast coast of the United States. During two different tidal conditions (high versus low tidal range) and when river flow was low, salinity and velocity data were collected over a semidiurnal tidal cycle in a 2.8 km long transect along the estuary axis. Water level data were recorded nearby. Mechanisms that influence salt transport characteristics are diagnosed from an analysis of the field data. Specifically, we investigated the relationship between tidal range and salinity through comparison of along-channel circulation characteristics, computed salt fluxes, and coefficients of vertical eddy diffusivity (Kz) based on a parameterization and on salt budget analysis. Findings indicate up-estuary tidally driven salt fluxes resulting from oscillatory salt transport are dominant near the pycnocline, while mean advective transport dominates near the bottom during both tidal range periods. Earlier research related to salt transport in estuaries with significant gravitational circulation suggests that up-estuary salt transport increases during low tidal ranges as a result of increased gravitational circulation. In the CFRE, in contrast, net (tidally averaged) near-bottom along-channel velocities are greater during higher tidal range conditions than during lower tidal range conditions. Findings indicate stronger tidal forcing and associated mixing contribute to greater near-bottom salinity gradients and, consequently, increased baroclinic circulation. Lower near-bottom salinities during the higher tidal range period are a result of a combination of increased vertical turbulent salt fluxes near the pycnocline and increased bottom-generated mixing.

  18. Particle dynamics of 7Be, 210Pb and the implications of sedimentation of heavy metals in the Wenjiao/Wenchang and Wanquan River estuaries, Hainan, China

    Science.gov (United States)

    Huang, Dekun; Du, Jinzhou; Zhang, Jing

    2011-07-01

    Radionuclides (i.e., 7Be and 210Pb) can be used to trace particle and sediment dynamics and to quantify coastal oceanic processes with time scales ranging from a few days to a hundred years. Here, we study the settling dynamics of suspended particles and the implication by sedimentary heavy metals in the Wenjiao/Wenchang River and Wanquan River estuaries through the measurement of the particulate 7Be and 210Pb nuclides. Activity in the particulate phase had a range of 2.1-54.5 and 4.6-67.9 Bq kg -1 for 7Be and excess 210Pb ( 210Pb xs), respectively, in the Wenjiao/Wenchang River estuary. In the Wanquan River estuary, activity is in the range of 1.2-43.5 Bq kg -1 for 7Be and 6.2-194.5 Bq kg -1 for 210Pb xs. At the same time, activity in the dissolved phase had a range of 0.46-1.26 and 0.30-1.17 Bq m -3 for 7Be and 210Pb, respectively, in the Wenjiao/Wenchang River estuary; ranges of 0.10-2.31 and 0.09-1.87 Bq m -3 for 7Be and 210Pb, respectively, were observed in the Wanquan River estuary. The distribution coefficients ( K d) for the two nuclides decreased within increased in suspended particle matters (SPM) concentration and/or salinity in Wanquan River estuary. The residence times of particulate 7Be and 210Pb xs had ranges of 0.4-1.6 and 1.65-5.15 days, respectively, in the Wenjiao/Wenchang River estuary; and ranges of 0.02-3.2 and 0.61-4.44 days, respectively in the Wanquan River estuary. All residence times for the two nuclides increased in the seaward direction. In the Wenjiao/Wenchang River estuary, we found that 11.8-21.0% of Cu, 3.0-9.0% of Zn and 43.2-69.9% for Cd is removed from the water column and deposited into the estuary, and 24.2-34.8% for Cu, 7.2-23.8% for Zn, and 70.0-82.5% for Cd in the Wanquan River estuary, respectively.

  19. Evaluation of the Ecotoxicity of Sediments from Yangtze River Estuary and Contribution of Priority PAHs to Ah Receptor-Mediated Activities

    OpenAIRE

    Liu, Li; CHEN, Ling; SHAO, YING; Lili ZHANG; Floehr, Tilman; Xiao, Hongxia; Yan, Yan; Eichbaum, Kathrin; Hollert, Henner; Wu, Lingling

    2014-01-01

    In this study, in vitro bioassays were performed to assess the ecotoxicological potential of sediments from Yangtze River estuary. The cytotoxicity and aryl hydrocarbon receptor (AhR)-mediated toxicity of sediment extracts with rainbow trout (Oncorhynchus mykiss) liver cells were determined by neutral red retention and 7-ethoxyresorufin-O-deethylase assays. The cytotoxicity and AhR-mediated activity of sediments from the Yangtze River estuary ranged from low level to moderate level compared w...

  20. Management of a tropical river: Impacts on the resilience of the Senegal river estuary

    OpenAIRE

    Kane, Coura; Alioune KANE; Humbert, Joël

    2014-01-01

    Tropical rivers are under constant pressure and are subjected to flood control policy and planning. The Senegal River has been, for more than thirty years, under multiple types of management and planning. That has become recently more important because of significant hydro-climatic variability that has occurred during recent years. Higher levels of winter rainfall have resulted in frequent occurrence of flooding which guided Senegalese authorities to create an artificial opening on the sand o...

  1. Delineation of the sources and sinks of heterogeneously distributed methane in the Pearl River and its estuary

    Science.gov (United States)

    Wang, J.; Xie, W.; Wei, Y.; Zhang, C.

    2013-12-01

    Methane in low temperature environments is mostly produced by methanogens. Sharp decrease in methane concentration has been observed from freshwater to marine water in coastal regions. The goal of this study was to delineate the sources and sinks of methane from the lower Pearl River (including, North, West, and East segments) and its estuary along a salinity gradient (0.0 % to 3.4%). Methane concentration in lower Pearl River ranged from 50.1 to 10578 nmol L-1 in the winter (average = 565.5 × 1464.9 nmol L-1) and from 38.4 to 974.1 nmol L-1 in the summer (average = 179.6 × 165.7 nmol L-1). In the estuary, however, methane concentration was 5-10 folds lower in winter and 3-8 folds lower in summer. The sea-to-air methane flux was also much higher in the fresh water (3159.6 umol/d.m2) than in the estuary (528.1 umol/d.m2). Abnormally high methane concentrations and methane flux in the East Pearl River appear to be associated with effluents of industrial or municipal wastes. DNA sequencing of the archaeal 16S rRNA gene indicates predominance of methanogens in the freshwater and their disappearance in the estuary. This is supported by the archaeal lipoid analysis, which showed the predominance of archaeol and caldarchaeol that characterize the methanogens. It is unknown, however, how aerobic (bacteria) and anerobic (archaea) methanotrophs may be involved in the oxidation of methane in the estuary environment where methane consumption is apparently occurring.

  2. Shallow Sediment Trace Metal Concentrations and Short-Term Accumulation Rates in the Neponset River Estuary, Massachusetts, USA

    Science.gov (United States)

    Spencer, J. R.; Zhu, J.; Olsen, C. R.

    2010-12-01

    The Neponset River estuary is a small estuary that drains into the Boston Harbor on the east coast of the United States. It is also a highly urbanized estuary and has a long history of urban development over 450 years. In July 2006, six sediment cores were collected in the Neponset River estuary to examine particle dynamics and sediment accumulation via radionuclide (Beryllium-7) dating, and to determine sediment metal concentrations (As, Cu, Pb, and Zn) via ED-XRF measurements. Measured sediment Be-7 profiles indicate various sedimentation environments, where sediment accumulation, resuspension or redeposition is likely to occur. High metal concentrations were often corresponding to high Be-7 inventories in sediment cores. Possible sources of trace metal contaminants in the water column include: storm water run-off, Combined Sewer Overflows (CSOs), a well-documented industrial pollution event that occurred upstream in the early to mid twentieth century, and the resuspension of sediment. Existing and future data will provide baseline information for quantifying the effects of the proposed and pending environmental restoration project, which includes the removal of the Baker Dam. The combined pre- and post-Dam removal data may then be used in cost-benefit analyses for other similar estuarine restoration projects.

  3. The Taw River Catchment and Estuary: A case study for the effects of NVZ measures Part 1 – The Freshwater Catchment (Draft)

    OpenAIRE

    Williams, Richard; Newman, Jonathan

    2006-01-01

    The estuary of the River Taw and its freshwater catchment has been designated as an NVZ on the basis that its estuary is eutrophic. A small part of the catchment drained by the Ashmill Stream has a second designation because it has nitrate concentrations that exceed those set down in the drinking water directive. The Taw estuary catchment covers 1126 km2 and is drained by seven rivers, the Taw, the Caen, the Venn, the Knowle Water, the Bradiford Water, the Langham and the Yeo (...

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

    Science.gov (United States)

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

    2006-12-01

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

  5. 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.

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

    Science.gov (United States)

    Liu, Bo; de Swart, Huib E.

    2015-12-01

    Field observations in estuaries reveal that phytoplankton blooms are strongly affected by advection processes related to river flow. To gain quantitative insight into this dependence, experiments were performed with a new idealised model that couples physical and biological processes. Advection of phytoplankton and nutrient by subtidal flow was explicitly accounted for, as well as longitudinal and vertical mixing processes. Results show that the idealised model is capable of reproducing the observed bloom. The specific spatial distribution of phytoplankton population emerges because the latter is suppressed in the upper reach by the advection processes, and the growth is limited in the lower reach by low nutrient concentrations. A sensitivity study of model results to different river discharges reveals the presence of three regimes. In the low discharge regime, blooms form because growth is faster than decay due to advection processes. In the high discharge regime, the situation is opposite and no blooms form. If time scales of growth and advection are comparable (in moderate discharge regime), phytoplankton population increases significantly slower compared to the low discharge regime. Results of additional model runs, in which water depth and the e-folding length scale of estuarine width convergence were varied, revealed that the three regimes occur in all these cases.

  7. Artificial radionuclides in sediments of the Don River Estuary and Azov Sea

    Energy Technology Data Exchange (ETDEWEB)

    Matishov, Genady G.; Matishov, Dimitry G.; Namjatov, Alexey A.; Carroll, JoLynn E-mail: jolynn.carroll@akvaplan.niva.no; Dahle, Salve

    2002-07-01

    The Don River Estuary-Azov Sea system is an extension of the shallow continental shelf area of the Black Sea. A large data set of artificial radionuclides in bottom sediments of the Azov Sea has been compiled in order to examine the storage and migration of radionuclides within this highly restricted inland sea and to estimate the annual dose received by individuals in the local population who regularly consume fish. In recent years (1997-1999), the radionuclide content of surface sediments has been: {sup 137}Cs{<=}0.5-100 Bq/kg d.w. (mean=33.8{+-}25.9 Bq/kg d.w., n=57), {sup 90}Sr=0.2-5.7 Bq/kg d.w. (mean=2.1{+-}1.4 Bq/kg d.w., n=34) and {sup 239,240}Pu=0.31-0.51 Bq/kg d.w. (n=2). In general, {sup 137}Cs activities increase with distance from the mouth of the Don River and correlate negatively with sediment grain size (r{sup 2}=0.77, n=21). The annual {sup 137}Cs-derived dose received by an individual through the trophic chain water-fish-humans ({approx}10{sup -6} Sv/yr) is well below regulatory recommended limits, indicating that current levels of radioactivity in the environment pose no threat to commercial fisheries operations for the bordering nations of Russia and Ukraine.

  8. 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  1) and 6 showed medium risk (0.1 ? QR < 1). The single chemical posed high risk to fish included DDTs, triazophos, fenvalerate, bifenthrin and cyfluthrin, and those showed medium risk included dicofol, butachlor, isocarbophos, terbufos and cyhalothrin. There were 14 single pesticides detected with concentration above 100 ng L(-1) in this study and the pesticide with the highest concentration was procymidone (3904 ng L(-1)). Further experiments illustrated that procymidone could disrupt the expression of vitellogenin in the estuarine fish even at environmental concentrations. DDTs, dicofol, triazophos, isocarbophos, terbufos, cyfluthrin, bifenthrin, fenvalerate, cyhalothrin, butachlor and procymidone have become the significant pesticides and should be considered in aquatic ecosystem risk management. PMID:26461443

  9. Artificial radionuclides in sediments of the Don River Estuary and Azov Sea.

    Science.gov (United States)

    Matishov, Genady G; Matishov, Dimitry G; Namjatov, Alexey A; Carroll, JoLynn; Dahle, Salve

    2002-01-01

    The Don River Estuary-Azov Sea system is an extension of the shallow continental shelf area of the Black Sea. A large data set of artificial radionuclides in bottom sediments of the Azov Sea has been compiled in order to examine the storage and migration of radionuclides within this highly restricted inland sea and to estimate the annual dose received by individuals in the local population who regularly consume fish. In recent years (1997-1999), the radionuclide content of surface sediments has been: 137Cs < or = 0.5-100 Bq/kg d.w. (mean = 33.8 +/- 25.9 Bq/kg d.w., n = 57), 90Sr = 0.2-5.7 Bq/kg d.w. (mean = 2.1 +/- 1.4 Bq/kg d.w., n = 34) and 239,240Pu = 0.31-0.51 Bq/kg d.w. (n = 2). In general, 137Cs activities increase with distance from the mouth of the Don River and correlate negatively with sediment grain size (r2 = 0.77, n = 21). The annual 137Cs-derived dose received by an individual through the trophic chain water-fish-humans (approximately 10(-6) Sv/yr) is well below regulatory recommended limits, indicating that current levels of radioactivity in the environment pose no threat to commercial fisheries operations for the bordering nations of Russia and Ukraine. PMID:11954720

  10. Artificial radionuclides in sediments of the Don River Estuary and Azov Sea

    International Nuclear Information System (INIS)

    The Don River Estuary-Azov Sea system is an extension of the shallow continental shelf area of the Black Sea. A large data set of artificial radionuclides in bottom sediments of the Azov Sea has been compiled in order to examine the storage and migration of radionuclides within this highly restricted inland sea and to estimate the annual dose received by individuals in the local population who regularly consume fish. In recent years (1997-1999), the radionuclide content of surface sediments has been: 137Cs?0.5-100 Bq/kg d.w. (mean=33.8±25.9 Bq/kg d.w., n=57), 90Sr=0.2-5.7 Bq/kg d.w. (mean=2.1±1.4 Bq/kg d.w., n=34) and 239,240Pu=0.31-0.51 Bq/kg d.w. (n=2). In general, 137Cs activities increase with distance from the mouth of the Don River and correlate negatively with sediment grain size (r2=0.77, n=21). The annual 137Cs-derived dose received by an individual through the trophic chain water-fish-humans (?10-6 Sv/yr) is well below regulatory recommended limits, indicating that current levels of radioactivity in the environment pose no threat to commercial fisheries operations for the bordering nations of Russia and Ukraine

  11. 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.

  12. Spatiotemporal variability of wet atmospheric nitrogen deposition to the Neuse River Estuary, North Carolina

    Energy Technology Data Exchange (ETDEWEB)

    Whitall, D.R.; Paerl, H.W. [University of North Carolina, Morehad City, NC (USA). Inst. of Marine Sciences

    2001-10-01

    Excessive nitrogen (N) loading to N-sensitive waters such as the Neuse River estuary (North Carolina) has been shown to promote changes in microbial and algal community composition and function (harmful algal blooms), hypoxia and anoxia, and fish kills. Previous studies have estimated that wet atmospheric deposition of nitrogen (WAD-N), as deposition of dissolved inorganic nitrogen (DIN: NO{sub 3}{sup -} NH{sub 3}/NH{sub 4}{sup +}) and dissolved organic nitrogen, may contribute at least 15% of the total externally supplied or 'new' N flux to the coastal waters of North Carolina. In a 3-yr study from June 1996 to June 1999, the weekly wet deposition of inorganic and organic N was counted at eleven sites on a northwest-southeast transect in the watershed. The annual mean total (wet DIN + wet organics) WAD-N flux for (15,026 Mg N/yr). Seasonally the spring (March-May) and summer (June - August) months contain the highest total weekly N depositions; this pattern appears to be driven by N concentration in precipitation. There is also spatial variability in WAD-N deposition; in general, the upper portion of the watershed receives the lowest annual deposition and the middle portion of the watershed receives the highest deposition. Based on a range of watershed N retention and in-stream riverine processing values, it was estimated that this flux contributes approximately 24% of the total 'new' N flux to the estuary. 61 refs., 4 figs., 4 tabs.

  13. 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

    2016-01-01

    The Changjiang River estuary and adjacent waters are one of the most notable regions for red tides/harmful algal blooms in China's coastal waters. In this study, phytoplankton samples were collected and analyzed during the outbreak stage of red tides in May 2009. It was found that dinoflagellates, Prorocentrum donghaiense and Karenia mikimotoi, and diatoms, Skeletonema spp. and Paralia sulcata, were the major taxa dominating the phytoplankton community. Cluster analysis, non-metric multidimensional scaling (NMDS) and analysis of similarities (ANOSIM) was conducted on a data matrix including taxa composition and cell abundance of the phytoplankton samples. The analyses categorized the samples into three groups at a similarity level of 30%. Group I was characterized by estuarine diatoms and distributed mainly in the highly turbid estuarine region. Group II, which was dominated by the diatom Skeletonema spp. and represented the red tide of Skeletonema spp., was situated around Group I in the sea area west of 122°50'E. Group III was characterized by a high proportion of dinoflagellates and was found further offshore compared with Groups I and II. Group III was further divided into two subgroups (III-S1 and III-S2) at a similarity level of 40%. Group III-S1 was characterized by the presence of the benthic diatom P. sulcata, representing phytoplankton samples collected either from the bottom or from the sea area affected by upwelling. Group III-S2 was dominated by dinoflagellates and represented red tides formed by P. donghaiense and K. mikimotoi. A gradual change of red-tide causative species was observed from the estuary to the offshore sea area, from diatoms to armored dinoflagellates and then unarmored dinoflagellates. Environmental factors associated with each group, and thus affecting the distribution of phytoplankton and red tides, are discussed.

  14. Resuspension and estuarine nutrient cycling: insights from the Neuse River Estuary

    Science.gov (United States)

    Corbett, D. R.

    2010-10-01

    For at least the past several decades, North Carolina's Neuse River Estuary (NRE) has been subject to water quality problems relating to increased eutrophication. Research initiated in the past several years have addressed the nutrient processes of the water column and the passive diffusion processes of the benthic sedimentary environment. Resuspension of bottom sediments, by bioturbation, tides, or winds, may also have a significant effect on the flux of nutrients in an estuarine system These processes can result in the advective transport of sediment porewater, rich with nitrogen, phosphorus and carbon, into the water column. Thus, estimates of nutrient and carbon inputs from the sediments may be too low. This study focused on the potential change in bottom water nutrient concentrations associated with measured resuspension events. Previous research used short-lived radionuclides and meteorological data to characterize the sediment dynamics of the benthic system of the estuary. These techniques in conjunction with the presented porewater inventories allowed evaluation of the depth to which sediments have been disturbed and the advective flux of nutrients to the water column. The largest removal episode occurred in the lower NRE as the result of a wind event and was estimated that the top 2.2 cm of sediment and corresponding porewater were removed. NH4+ advective flux (resuspended) was 2 to 6 times greater than simply diffusion. Phosphate fluxes were estimated to be 15 times greater than the benthic diffusive flux. Bottom water conditions with elevated NH4+ and PO43- indicate that nutrients stored in the sediments continue to play an important role in overall water quality and this study suggests that the advective flux of nutrients to the water column is critical to understand estuarine nutrient cycling.

  15. Resuspension and estuarine nutrient cycling: insights from the Neuse River Estuary

    Directory of Open Access Journals (Sweden)

    D. R. Corbett

    2010-04-01

    Full Text Available For at least the past several decades, North Carolina's Neuse River Estuary (NRE has been subject to water quality problems relating to increased eutrophication. Research studies initiated in the past several years have addressed the complex nutrient cycles in this system. Most of this research, however, is concerned with the nutrient processes of the water column and the passive diffusion processes of the benthic sedimentary environment. Resuspension of bottom sediments, by bioturbation, tides, or wind-generated waves, may have a significant effect on the flux of nutrients in an estuarine system These processes can result in the advective transport of sediment porewater, rich with nitrogen, phosphorus and carbon, into the water column. Thus, estimates of nutrient and carbon inputs from the sediments may be too low.

    This study focused on the potential change in porewater and bottom water nutrient concentrations associated with measured resuspension events. Previous research used short-lived radionuclides and meteorological data to characterize the sediment dynamics of the benthic system of the estuary. These techniques in conjunction with the presented porewater inventories allowed evaluation of the depth to which sediments have been disturbed and the advective flux of nutrients to the water column. The largest removal episode occurred in the lower NRE as the result of a wind event and was estimated that the top 2.2 cm of sediment and corresponding porewater were removed. NH4+ advective flux (resuspended was 2 to 6 times greater than simply diffusion. Phosphate fluxes were estimated to be 15 times greater than the benthic diffusive flux. Bottom water conditions with elevated NH4+ and PO43? indicate that nutrients stored in the sediments continue to play an important role in overall water quality and this study suggests that the advective flux of nutrients to the water column is critical to understand estuarine nutrient cycling.

  16. Resuspension and estuarine nutrient cycling: insights from the Neuse River Estuary

    Directory of Open Access Journals (Sweden)

    D. R. Corbett

    2010-10-01

    Full Text Available For at least the past several decades, North Carolina's Neuse River Estuary (NRE has been subject to water quality problems relating to increased eutrophication. Research initiated in the past several years have addressed the nutrient processes of the water column and the passive diffusion processes of the benthic sedimentary environment. Resuspension of bottom sediments, by bioturbation, tides, or winds, may also have a significant effect on the flux of nutrients in an estuarine system These processes can result in the advective transport of sediment porewater, rich with nitrogen, phosphorus and carbon, into the water column. Thus, estimates of nutrient and carbon inputs from the sediments may be too low.

    This study focused on the potential change in bottom water nutrient concentrations associated with measured resuspension events. Previous research used short-lived radionuclides and meteorological data to characterize the sediment dynamics of the benthic system of the estuary. These techniques in conjunction with the presented porewater inventories allowed evaluation of the depth to which sediments have been disturbed and the advective flux of nutrients to the water column. The largest removal episode occurred in the lower NRE as the result of a wind event and was estimated that the top 2.2 cm of sediment and corresponding porewater were removed. NH4+ advective flux (resuspended was 2 to 6 times greater than simply diffusion. Phosphate fluxes were estimated to be 15 times greater than the benthic diffusive flux. Bottom water conditions with elevated NH4+ and PO43? indicate that nutrients stored in the sediments continue to play an important role in overall water quality and this study suggests that the advective flux of nutrients to the water column is critical to understand estuarine nutrient cycling.

  17. 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 of the river at higher rates, with estimated survival probabilities of 84% and 86%, respectively. The influence of route of passage at the lower three dams in the FCRPS on juvenile salmonid survival appeared to be relatively direct and immediate. Significant differences in estimated survival probabilities of juvenile salmonid smolts among groups with different dam passage experiences were often detected between the dams and rkm 153. In contrast, the influence of route of passage on survival to the mouth of the Columbia River was not apparent among the groups of tagged juvenile salmonids with different FCRPS passage experiences after they had already survived to a point about 80 km downstream of Bonneville Dam. Yearling Chinook salmon and steelhead smolts that migrated through the lower estuary in off-channel habitats took two to three times longer to travel through these lower reaches and their estimated survival probabilities were not significantly different from that of their cohorts which migrated in or near the navigation channel. A large proportion of the tagged juvenile salmonids migrating in or near the navigation channel in the lower estuary crossed from the south side of the estuary near Astoria, Oregon and passed through relatively shallow expansive sand flats (Taylor Sands) to the North Channel along the Washington shore of the estuary. This migratory behavior may contribute to the avian predation losses observed on for fish (2 to 12% of fish in this study).

  18. 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 within wetland habitats fell to low levels by July, similar to the pattern observed at mainstem beach-seining sites and coincident with high water temperatures that approached or exceeded 19 C by mid-summer. Wetland habitats were used primarily by small subyearling Chinook salmon, with the smallest size ranges (i.e., rarely exceeding 70 mm by the end of the wetland rearing season) at scrub/shrub forested sites above rkm 50. Wetland sites of all types were utilized by a diversity of genetic stock groups, including less abundant groups such as Interior Summer/Fall Chinook.

  19. 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 of several Baltic Sea estuaries. • More information is needed on low salinity estuaries.

  20. Autochthonous and allochthonous contributions to mesozooplankton diet in a tidal river and estuary: integrating carbon isotope and fatty acid constraints

    OpenAIRE

    Van den Meersche, K.; van Rijswijk, P.; Soetaert, K; Middelburg, J.J.

    2009-01-01

    We examined the carbon sources used by bacteria and mesozooplankton in the Scheldt River and estuary (Belgium, The Netherlands) using a combined stable isotope and fatty acid composition approach. Water samples were collected monthly at six stations during 1 yr and analyzed for 13C of dissolved inorganic carbon, dissolved organic carbon (DOC), and particulate organic carbon (POC). Mesozooplankton was determined up to family, genus, or species level and analyzed for 13C and fatty acid content....

  1. Chemical risks associated with consumption of shellfish harvested on the north shore of the St. Lawrence River's lower estuary.

    OpenAIRE

    Gagnon, Fabien; Tremblay, Thierry; Rouette, Justine; Cartier, Jacques-François

    2004-01-01

    Shellfish have the capacity to accumulate chemical contaminants found in their biotope and therefore present a potential risk for consumers. This study was conducted to assess the chemical risks associated with consumption of shellfish harvested on the north shore of the St. Lawrence River's lower estuary. A survey was carried out on 162 recreational harvesters, and shellfish were sampled for chemical contaminant analysis. We quantified 10 metals, 22 polycyclic aromatic hydrocarbons (PAHs), 1...

  2. 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 Globigerinoides ruber pink Tropical Hurricane layers only Silicoflagellate sp Planktonic, marine Hurricane layers only

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

    Science.gov (United States)

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

    2015-02-01

    In the present study, 28 polycyclic aromatic hydrocarbons (PAHs) were investigated in four sediment cores collected from the main river estuaries of Chaohu Lake, one of the severely polluted lakes in China. The results indicate that elevated concentrations of total PAHs (?28PAH) were found in the samples from the estuary of Nanfei River (ENF), considering BaP-based total toxicity equivalent (TEQ-BaP) and toxic unit (TU) results; there are potential adverse environmental implications. The total organic carbon (TOC) played an important role on the accumulation of PAHs at ENF and the estuary of Tongyang River (ETY). The predominant PAHs are high molecular weight (HMW) homologous for all samples; as a result, industrial wastewater from a steel company is expectedly the key source of PAHs in ENF, while coke consumption would be the important source of PAHs at other three sampling sites. Vertical distribution of PAHs in the sediment cores could be explained by the local social and economic activities. Furthermore, a minor variation of PAH composition in the sediment core could be justified by the stable structure of energy consumption in the Anhui Province. These results justify the need for further enhancement of industrial wastewater treatment and development of renewable energies which are the key factors on the control of PAH pollution in China. PMID:24946702

  4. [Effects of Long-term Implementation of the Flow-Sediment Regulation Scheme on Grain and Clay Compositions of Inshore Sediments in the Yellow River Estuary].

    Science.gov (United States)

    Wang, Miao-miao; Sun, Zhi-gao; Lu, Xiao-ning; Wang, Wei; Wang, Chuan-yuan

    2015-04-01

    Based on the laser particle size and X-ray diffraction (XRD) analysis, 28 sediment samples collected from the inshore region of the Yellow River estuary in October 2013 were determined to discuss the influence of long-term implementation of the flow-sediment regulation scheme (FSRS, initiated in 2002) on the distributions of grain size and clay components (smectite, illite, kaolinite and chlorite) in sediments. Results showed that, after the FSRS was implemented for more than 10 years, although the proportion of sand in inshore sediments of the Yellow River estuary was higher (average value, 23.5%) than those in sediments of the Bohai Sea and the Yellow River, silt was predominated (average value, 59.1%) and clay components were relatively low (average value, 17.4%). The clay components in sediments of the inshore region in the Yellow River estuary were close with those in the Yellow River. The situation was greatly changed due to the implementation of FSRS since 2002, and the clay components were in the order of illite > smectite > chlorite > kaolinite. This study also indicated that, compared to large-scale investigation in Bohai Sea, the local study on the inshore region of the Yellow River estuary was more favorable for revealing the effects of long-term implementation of the FSRS on sedimentation environment of the Yellow River estuary. PMID:26164898

  5. [Spectral absorption properties of the water constituents in the estuary of Zhujiang River].

    Science.gov (United States)

    Wang, Shan-shan; Wang, Yong-bo; Fu, Qing-hua; Yin, Bin; Li, Yun-mei

    2014-12-01

    Spectral absorption properties of the water constituents is the main factor affecting the light field under the surface of the water and the spectrum above the surface of the water. Thus, the study is useful for understanding of the water spectral property and the remote reversing of water quality parameters. Absorption properties of total suspended particles, non-algal particles, phytoplankton and CDOM were analyzed using the 30 samples collected in July 2013 in the estuary of Zhujiang River. The results indicated that: (1) the non-algal particles absorption dominated the absorption of the total suspended particles; (2) the absorption coefficient of the non-algal particles, which mainly came from the terrigenous deposits, decreased exponentially from short to long wavelength. In addition, the average value and spatial variation of the slope S(d) were higher than those in inland case- II waters; (3) the absorption coefficient of phytoplankton in 440 nm showed a better polynomial relationship with chlorophyll a concentration, while the absorption coefficient of phytoplankton in 675 nm linearly related with the chlorophyll a concentration. Moreover, the influence of accessory pigments on phytoplankton absorption coefficient mainly existed in the range of short wavelength, and Chlorophyll a was the main influencing factor for phytoplankton absorption in long wavelength. The specific absorption coefficient of phytoplankton decreased the power exponentially with the increase of the chlorophyll a concentration; (4) CDOM mainly came from the terrigenous sources and its spectral curve had an absorption shoulder between 250-290 nm. Thus, a piecewise S(g) fitting function could effectively express CDOM absorption properties, i.e., M value and S(g) value in period A (240-260 nm) showed a strong positive correlation. The M value was low, and the humic acid had a high proportion in CDOM; (5) the non-algal particles absorption dominated the total absorption in the estuary of Zhujiang River, and the contribution of the phytoplankton absorption to the total absorption was far lower than that of the non-algal particles. While the contribution of the CDOM was the lowest. The contribution of the CDOM absorption to the total absorption was relatively larger when the content of humic acid was higher. PMID:25826920

  6. Controls on Bacterial Concentrations in Sediment Grab Samples from the Hudson River Estuary

    Science.gov (United States)

    Batta, J.; Mailloux, B. J.; Nitsche, F. O.; Kenna, T. C.; Ferguson, A. S.; Cheung, J.; Layton, A.

    2010-12-01

    High levels of fecal bacteria resulting from sewage-related pollution are often present in the Hudson River Estuary. Die-off of the fecal bacteria in surface waters is relatively rapid but the fecal bacteria can also attach to particles and settle. It is known that fecal bacteria are present in the shallow sediments but controls on their distribution have not been closely examined. The goal of this work is to examine the relationship between the concentration of fecal indicator bacteria and sediment properties including estimates of sediment age. Forty sediment surface grabs were obtained from the Hudson River Estuary. Twenty samples were collected from near the George Washington Bridge (GWB) and twenty samples from a 15 mile transect near Hudson New York. Concentrations of fecal indicator bacteria were determined by the cultured based Enterolert and Colilert tests (Idexx Laboratories) and molecular based techniques for E. coli and Bacteroides. Sediments were analyzed for total metals, total organic carbon, grain size, and gamma emitting radionuclides including Beryllium-7, Lead-210, and Cesium-137. Enterococcus was present in the samples with a geometric mean of 88 cells/g and a range of 4 to 817 cells /g. Culturable E. Coli was present in the samples with a geometric mean of 168 cells /g and a range of 5 to 2247 cells /g. Enterococcus concentrations were significantly higher (p<0.05) in the northern transect. Molecular based concentrations were determined for the GWB samples and were significantly higher than culture based concentrations. Bacteroides was present in the samples with a geometric mean of 1.1x106 copies/g and a range of 3.9x104 to 4.7x106 copies /g. Molecular E. Coli was present in the samples with a geometric mean of 3.0x106 copies/g and a range of 8.7x104 to 8.9x107 copies /g. The results clearly show that a significant amount of fecal bacteria are present in the sediments. Simple linear correlations between bacterial concentrations and sediment properties have not been observed, but more complex relationships might exist.

  7. Organic fluxes of Cameroonian rivers into the Gulf of Guinea: a quantitative approach to biodegradation in estuary and plume

    OpenAIRE

    Giresse, P.; Cahet, G.

    1997-01-01

    The modern organic carbon flux of the Sanaga River and the rivers around the Bay of Douala is estimated to be 0.62-0.79 x 10(6) t yr(-1). In reality, mean Holocene sedimentation of organic carbon, including a presumed low biological production in the euphotic zone, is only 41-52 % of this-value. Substantial biodegradation in the salty and brackish turbid waters in the estuaries affects the POC and DOC arid corresponds to the highest bacterial densities. Between salinity 6 and 21, the data ind...

  8. 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.

    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.

  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. 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.

  11. 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.

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

    International Nuclear Information System (INIS)

    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 μg/g lipid) were more than 10 fold higher and congener distributions were highly enriched in Cl7-Cl10 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

  13. 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, ...

  14. 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/plume variability, the role of the estuary and plume on salmon survival, and functional changes in the estuary-plume system in response to climate and human activities.

  15. 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.

  16. Plutonium and radiocesium in the water column of the Hudson River Estuary

    International Nuclear Information System (INIS)

    Isotopes of plutonium (Pu), cesium (Cs), and cobalt (Co) introduced into the Hudson River Estuary from fallout deposition, the erosion of fallout-contaminated surface soils, and nuclear reactor effluent (isotopes of Cs and Co only) have been measured in water column samples collected from 1975 to 1980. The major conclusions drawn from the work are that: for water samples collected by the two laboratories over similar time periods, the mean concentrations of nonfilterable /sup 239,240/Pu (137Cs and /sup 239,240/Pu in suspended particulates were more divergent at 2270 +/- 920 pCi/kg (+/- 1 SD) and 1430 +/- 430 pCi/kg for 137Cs, and 19 +/- 8 pCi/kg and 12 +/- 4 pCi/kg for /sup 239,240/Pu. The behavior of /sup 239,240/Pu and 137Cs within the water column is shown to diverge within brackish waters. Specifically, the magnitude of the 137Cs distribution-coefficient (K/sub d/) can be expressed as an inverse power function of the chloride ion concentrations for chlorinities between 0.1 and 4 g Cl-/l. No difference in the /sup 239,240/Pu k/sub d/ has been observed between fresh and brackish waters. Based on the expected inventories of /sup 239,240/Pu and 137Cs within watershed soils, the current downstream transport of these radionuclides represents fractional mobilization rates on the order of 1-4 (x 10-4) per year

  17. Toxicity of sediment cores from Yangtze River estuary to zebrafish (Danio rerio) embryos.

    Science.gov (United States)

    Wang, Peipei; Zhang, Lili; Liu, Li; Chen, Ling; Gao, Hongwen; Wu, Lingling

    2015-11-01

    Toxicity evaluation is an important segment in sediment quality monitoring in order to protect aquatic organisms and human health. The purpose of this study is to assess the toxicity of sediments from three sediment cores in Yangtze River Estuary, China, using the zebrafish (Danio rerio) embryo tests. Fertilized zebrafish eggs were exposed to both whole sediments and sediment organic extracts prepared from collected sediments, in order to provide a comprehensive and realistic insight into the bioavailable toxicity potential of the sediments. As end points, development parameters (mortality, hatching rate, and abnormality) in the developing embryos were recorded during the 96-h exposure. The results showed that some samples increased mortality, inhibited the hatching of embryos, and induced morphological abnormalities. The embryonic toxicities presented serrated changes and irregular distribution with depth, which may be related to hydrodynamic effect and unstable environmental input. However, lethal and sub-lethal effects were more significant at the sub-surface sediments (10?40 cm), which indicated that the pollution is more serious in recent decades. PMID:25163567

  18. Infrastructure for collaborative science and societal applications in the Columbia River estuary

    Science.gov (United States)

    Baptista, António M.; Seaton, Charles; Wilkin, Michael P.; Riseman, Sarah F.; Needoba, Joseph A.; Maier, David; Turner, Paul J.; Kärnä, Tuomas; Lopez, Jesse E.; Herfort, Lydie; Megler, V. M.; McNeil, Craig; Crump, Byron C.; Peterson, Tawnya D.; Spitz, Yvette H.; Simon, Holly M.

    2015-12-01

    To meet societal needs, modern estuarine science needs to be interdisciplinary and collaborative, combine discovery with hypotheses testing, and be responsive to issues facing both regional and global stakeholders. Such an approach is best conducted with the benefit of data-rich environments, where information from sensors and models is openly accessible within convenient timeframes. Here, we introduce the operational infrastructure of one such data-rich environment, a collaboratory created to support (a) interdisciplinary research in the Columbia River estuary by the multi-institutional team of investigators of the Science and Technology Center for Coastal Margin Observation & Prediction and (b) the integration of scientific knowledge into regional decision making. Core components of the operational infrastructure are an observation network, a modeling system and a cyber-infrastructure, each of which is described. The observation network is anchored on an extensive array of long-term stations, many of them interdisciplinary, and is complemented by on-demand deployment of temporary stations and mobile platforms, often in coordinated field campaigns. The modeling system is based on finiteelement unstructured-grid codes and includes operational and process-oriented simulations of circulation, sediments and ecosystem processes. The flow of information is managed through a dedicated cyber-infrastructure, conversant with regional and national observing systems.

  19. Identification and apportionment of hazardous elements in the sediments in the Yangtze River estuary.

    Science.gov (United States)

    Wang, Jiawei; Liu, Ruimin; Wang, Haotian; Yu, Wenwen; Xu, Fei; Shen, Zhenyao

    2015-12-01

    In this study, positive matrix factorization (PMF) and principal components analysis (PCA) were combined to identify and apportion pollution-based sources of hazardous elements in the surface sediments in the Yangtze River estuary (YRE). Source identification analysis indicated that PC1, including Al, Fe, Mn, Cr, Ni, As, Cu, and Zn, can be defined as a sewage component; PC2, including Pb and Sb, can be considered as an atmospheric deposition component; and PC3, containing Cd and Hg, can be considered as an agricultural nonpoint component. To better identify the sources and quantitatively apportion the concentrations to their sources, eight sources were identified with PMF: agricultural/industrial sewage mixed (18.6 %), mining wastewater (15.9 %), agricultural fertilizer (14.5 %), atmospheric deposition (12.8 %), agricultural nonpoint (10.6 %), industrial wastewater (9.8 %), marine activity (9.0 %), and nickel plating industry (8.8 %). Overall, the hazardous element content seems to be more connected to anthropogenic activity instead of natural sources. The PCA results laid the foundation for the PMF analysis by providing a general classification of sources. PMF resolves more factors with a higher explained variance than PCA; PMF provided both the internal analysis and the quantitative analysis. The combination of the two methods can provide more reasonable and reliable results. PMID:26511260

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

    Science.gov (United States)

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

    2015-11-01

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

  1. 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.

  2. Methane (CH4) emission from a tidal marsh in the Min River estuary, southeast China.

    Science.gov (United States)

    Tong, Chuan; Wang, Wei-Qi; Zeng, Cong-Sheng; Marrs, Rob

    2010-01-01

    The total methane emission to the atmosphere and hydrosphere, and its seasonal variation, were estimated using an enclosed static chamber technique from a tidal marshes dominated by Phragmites australis (common reed) in the Min River estuary, southeast China. Measurements were taken at three tidal stages (before flood, during the flooding and ebbing process, and after ebb). Potential rates of methane production from the marsh sediment layers were also measured using an incubation technique. This P. australis tidal marsh was a net methane source, emitting 32.59 and 6.87 g CH(4) x m(-2) x yr(-1) to the atmosphere and hydrosphere, respectively. There was considerable monthly variation with emissions greater before flood in some months, whereas at other months emission was greater after ebb. The average methane fluxes were 5.13, 5.06 and 4.74 mg CH(4) m(-2) h(-1) before flood, during flooding and ebbing, and after ebb, respectively. Emissions to the tidewater and the atmosphere during the flooding and ebbing process were 2.98 and 2.08 mg CH(4) m(-2) h(-1),respectively. Sediment methane production potential (0-40 cm depth) ranged from 0.028-0.123 micro g CH(4) x g(-1) x d(-1), with the greatest production was in the surface soil. Methane fluxes had a significant correlation with atmospheric, sediment temperature and above ground biomass. The implications of these data for global warming are discussed briefly. PMID:20390897

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

    International Nuclear Information System (INIS)

    Fallout plutonium and radiocesium derived from both weapons testing and local reactor releases are found in the water column and sediments of the Hudson River in readily measurable amounts. The history of fallout delivery and dissolved phase runoff from the drainage basin of 80Sr, 137Cs, and /sup 239,240/Pu have been extensively documented since the mid-1950s. Sediment and water column concentrations of 134Cs, 137Cs, and /sup 239,240/Pu in the Hudson have also been documented since the mid-1960's and are summarized. Since the peak fallout years, substantial portions of the fallout radionuclides in the drainage basin have become unavailable to normal weathering processes as reflected by a measured decrease in the fallout nuclide transport to the waters of the tidal Hudson. Budget calculations indicate that plutonium may be transported into the estuary from the coastal ocean, and that desorption of radiocesium from particles has allowed a substantial fraction of radiocesium to be exported from the Hudson to marine waters. 29 references, 6 figures, 8 tables

  4. Faunal characteristics and sediment accumulation processes in the James River estuary, Virginia

    Science.gov (United States)

    Schaffner, Linda C.; Diaz, Robert J.; Olsen, Curtis R.; Larsen, Ingvar L.

    1987-08-01

    This study was designed to relate fauna characteristics and sediment accumulation processes in the James River, VA and was conducted during June 1981. Physical sedimentary and benthic biological parameters, as well as sediment structure and radionuclide profiles, were evaluated for 11 stations. Faunal distribution patterns reflected species' response to salinity changes along the estuarine gradient, but not to differences in sediment accumulation rates. Levels of bioturbation could not be predicted easily on the basis of faunal characteristics alone. Results suggest that the physical processes of erosion and deposition strongly influence the ability of macrobenthos to bioturbate sediments in this estuary. Areas of rapid deposition (>3 cm y -1) exhibit little evidence of bioturbation, as do areas where erosion, or relatively constant physical reworking of sediments, dominate. Areas with low sediment accumulation rates (0·5-3 cm y -1) exhibit the highest levels of mixing as evidenced in X-radiographs. Estuarine organisms inhabiting soft bottoms are typically 'opportunistic', shallow-living and short-lived species, and the composition of their communities is not strongly influenced by rates of deposition. Physical reworking of sediments is most likely to occur near to the sediment-water interface where reworking by shallow-living organisms is most intense. Sediment-mixing processes should be characterized using a range of approaches. The phasing of interactions among erosion, physical transport, deposition and biological mixing must be resolved on the appropriate time scales if the mechanics of processes governing the formation of the sedimentary record are to be elucidated.

  5. 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 of oxygen depletion, temperature was critical in determining the extent of hypoxia and anoxia in the estuary. These findings highlight the importance of how seasonal changes in flow events and environmental flow management can impact on estuarine oxygen depletion in a warming climate. This study provides an improved understanding of the controls on hypoxia and anoxia in riverine estuaries, which is essential to support improved prediction of nutrient dynamics and ecological heath.

  6. 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 ?mol m(-2)d(-1) and 92.8 ?mol m(-2)d(-1) for CH4 and N2O, respectively. PMID:24993513

  7. 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.

  8. [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. PMID:22007462

  9. Long-term changes in sedimentary diatom assemblages and their environmental implications in the Changjiang (Yangtze) River estuary, China

    Science.gov (United States)

    Cheng, Fangjin; Yu, Zhiming; Song, Xiuxian

    2014-01-01

    Long-term data on diatom assemblages in a sediment core (60 cm) obtained from the Changjiang (Yangtze) River estuary were analyzed in order to assess the environmental changes that took place in the approximately 38 years (as determined by 210Pb measurements), i.e., between 1974 and 2012, of sediment accumulation. From the sediment core, 62 diatom taxa and genera were identified. The diatom biomass in the core generally increased beginning in the mid-1990s (core depth: 35 cm), accompanied by a shift in the dominant species from Podosira stelliger and two species of Cyclotella ( C. stylorum and C. striata) to Paralia sulcata, three species of Thalassiosira ( T. eccentria, T. oestrupii, and T. excentrica), Actinoptychus undulates, and Thalassionema nitzschioides. The changes in both species diversity and abundance suggested that since the 1980s the estuary has undergone extensive eutrophication. This conclusion was supported by the increased proportion of planktonic species, another indicator of high nutrients inputs, in the Changjiang River estuary.

  10. Dissolved inorganic carbon (DIC) and its ?13C in the Ganga (Hooghly) River estuary, India: Evidence of DIC generation via organic carbon degradation and carbonate dissolution

    Science.gov (United States)

    Samanta, Saumik; Dalai, Tarun K.; Pattanaik, Jitendra K.; Rai, Santosh K.; Mazumdar, Aninda

    2015-09-01

    In this study, we present comprehensive data on dissolved Ca, dissolved inorganic carbon (DIC) and its carbon isotope composition (?13CDIC) of (i) the Ganga (Hooghly) River estuary water sampled during six seasons of contrasting water discharge over 2 years (2012 and 2013), (ii) shallow groundwater from areas adjacent to the estuary and (iii) industrial effluent water and urban wastewater draining into the estuary. Mass balance calculations indicate that processes other than the conservative mixing of seawater and river water are needed to explain the measured DIC and ?13CDIC. Results of mixing calculations in conjunction with the estimated undersaturated levels of dissolved O2 suggest that biological respiration and organic carbon degradation dominate over biological production in the estuary. An important outcome of this study is that a significant amount of DIC and dissolved Ca is produced within the estuary at salinity ?10, particularly during the monsoon period. Based on consideration of mass balance and a strong positive correlation observed between the "excess" DIC and "excess" Ca, we contend that the dominant source of DIC generated within the estuary is carbonate dissolution that is inferred to be operating in conjunction with degradation of organic carbon. Calculations show that groundwater cannot account for the observed "excess" Ca in the high salinity zone. Estimated DIC contributions from anthropogenic activity are minor, and they constitute ca. 2-3% of the river water DIC concentrations. The estimated annual DIC flux from the estuary to the Bay of Bengal is ca. (3-4) × 1012 g, of which ca. 40-50% is generated within the estuary. The monsoon periods account for the majority (ca. 70%) of the annual DIC generation in the estuary. The annual DIC flux from the Hooghly estuary accounts for ca. 1% of the global river DIC flux to the oceans. This is disproportionately higher than the water contribution from the Hooghly River to the oceans, which 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 to the world's oceans.

  11. A choice experiment application to estimate willingness to pay for controlling excessive recreational fishing demand at the Sundays River Estuary, South Africa

    Scientific Electronic Library Online (English)

    DE, Lee; SG, Hosking; M, du Preez.

    2014-01-01

    Full Text Available The Sundays River Estuary, situated in the Eastern Cape, South Africa, has excessive recreational demand for estuarine services, specifically recreational fishing. The estuary has been over-fished, putting its sustainability at risk. Various management interventions may be required in order to save [...] it, but how is this to be done without reducing welfare? The main aim of this paper is twofold: first, to assess and comprehend the economic value of the estuarine resources at stake; and, second, to propose policy measures to redress the situation (excessive demand, specifically recreational fishing). An application of a choice experiment reveals that the physical size of fish stocks is a very important predictor of recreational choice at the Sundays River Estuary, and it is recommended that demand be curtailed through an increase in the boat license fee for using the estuary of ZAR174 per annum

  12. Uranium isotopes in rivers, estuaries and adjacent coastal sediments of western India: their weathering, transport and oceanic budget

    International Nuclear Information System (INIS)

    The two major river systems on the west coast of India, Narbada and Tapti, their estuaries and the coastal Arabian sea sediments have been extensively studied for their uranium concentrations and 234U/238U activity ratios. The 238U concentrations in the aqueous phase of these river systems exhibit a strong positive correlation with the sum of the major cations, and with the HCO3- ion contents. The abundance ratio of dissolved U to the sum of the major cations in these waters is similar to their ratio in typical crustal rocks. In the estuaries, both 238U and its great-grand daughter 234U behave conservatively beyond chlorosities 0.14 g/l. A review of the uranium isotope measurements in river waters yield a discharge weighted-average 238U concentration of 0.22 μg/l with a 234U/238U activity ratio of 1.20 +-0.06. The residence time of uranium isotopes in the oceans estimated from the 238U concentration and the 234U/238U A.R. of the rivers yield conflicting results; the material balance of uranium isotopes in the marine environment still remains a paradox. If the disparity between the results is real, then an additional 234U flux of about 0.25 dpm/cm2.103 yr into the oceans is necessitated. (author)

  13. Comparative Study among Microflora in El-manzala Lake Water and Rashid (Rosetta Estuary of Nile River, Egypt

    Directory of Open Access Journals (Sweden)

    Sohair A. Mostafa

    2003-01-01

    Full Text Available Phytoplankton and microbiological analysis of three different sites of each of El-Manzala Lake Water and Rashid branch of the River Nile of Egypt were examined. The results were compared and correlated with each other and with certain physico-chemical parameters using MVSP Ver. 3.1 program for Canonical Corresponding Analysis (CCA. Chlorophyceae and Bacillariophyceae represented 47.6 and 45.9% of the total phytoplankton in El-Manzala Lake Water, which was more, polluted than Rashid estuary water. Chlorophyceae was predominant (51.7% in Rashid estuary water. Heterotrophic plate counts and indicators of faecal contamination were higher in El-Manzala than in Rashid water whereas both halophilic and halotolerant bacteria were higher at Rashid than El-Manzala locations. Thermophilic and/or thermotolerant fungi and bacteria were more abundant in El-Manzala water than in Rashid water.

  14. Pluriannual watershed discharges of hg into a tropical semi-arid estuary of the Jaguaribe river, NE Brazil

    Scientific Electronic Library Online (English)

    Luiz D., Lacerda; Francisco J. S., Dias; Rozane V., Marins; Talita M., Soares; José Marcos O., Godoy; Maria Luiza D. P., Godoy.

    2013-11-01

    Full Text Available Fluxos de Hg foram determinados entre 2005 e 2009 nas estações seca e chuvosa no estuário do Rio Jaguaribe, que desagua no Oceano Atlântico Equatorial, NE do Brasil. Na estação chuvosa a massa d'água no estuário apresenta um curto tempo de residência no estuário (0,8 dias), quatro vezes menor que na [...] seca (3,1 dias). As concentrações e fluxos de Hg dissolvido ( Abstract in english Mercury fluxes were measured during the dry and rainy seasons (2005 to 2009) at the Jaguaribe River estuary, which discharges into the Equatorial Atlantic Ocean in NE Brazil. During rainy periods, the water masses exhibited a short residence time within the estuary (0.8 days). During dry periods, se [...] awater choked the fluvial discharge, resulting in longer residence times (3.1 days). Dissolved (

  15. 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.

  16. 76 FR 14924 - Takes of Marine Mammals Incidental to Specified Activities; Russian River Estuary Management...

    Science.gov (United States)

    2011-03-18

    ...March in the past ten years. Potential...monitoring data exists for...regular estuary management activity...operations, past monitoring...low in the past (see Table...monitoring data, NMFS has...during estuary management activities...in the years since...

  17. 76 FR 8345 - Endangered and Threatened Species; Recovery Plan Module for Columbia River Estuary Salmon and...

    Science.gov (United States)

    2011-02-14

    ... comments on the Proposed Estuary Module was published in the Federal Register on January 8, 2008 (73 FR 161... access to low- velocity habitats. Ship wake stranding is an example of another threat to salmon and... degraded. Ship wakes..... CRE-12: Reduce the effects of vessel wake stranding in the estuary. \\1\\...

  18. Status of the population structure of the mangrove crab Ucides cordatus (Decapoda: Ocypodidae) on the Piraquê-açu River estuary, Espírito Santo, Brazil

    OpenAIRE

    Rita de Cássia Conti; Rosebel Cunha Nalesso

    2010-01-01

    The land crab Ucides cordatus is a keystone species of neotropical mangrove forests and an important resource of the artisanal fisheries. The spatial and temporal distribution of U. cordatus in the mangrove area of the Piraquê-açu river estuary was determined following a longitudinal estuarine salinity gradient (lower, middle, upper estuary) and along the vertical intertidal gradient. The numbers of open and closed burrows were counted monthly on fixed transects, the inhabiting crabs were cau...

  19. Natural 222Rn and 220Rn indicate the impact of the Water–Sediment Regulation Scheme (WSRS) on submarine groundwater discharge in the Yellow River estuary, China

    International Nuclear Information System (INIS)

    Highlights: • 220Rn and 222Rn were combined to locate intensive SGD sites. • Influence of WSRS to SGD was found for the first time. • SGD was a dominant nutrient pathway in the Yellow River estuary. - Abstract: Submarine groundwater discharge (SGD) in estuaries brings important influences to coastal ecosystems. In this study, we observed significant SGD in the Yellow River estuary, including a fresh component, during the Water–Sediment Regulation Scheme (WSRS) period. We used the 222Rn and 220Rn isotope pair to locate sites of significant SGD within the study area. Three apparent SGD locations were found during a non-WSRS period, one of which became much more pronounced, according to the remarkably elevated radon levels, during the WSRS. Increased river discharge (from 245 m3 s?1 to 3560 m3 s?1) and the elevated river water level (from 11 m to 13 m) during the WSRS led to a higher hydraulic head, enhancing groundwater discharge in the estuary. Our results suggest that high river discharge (>3000 m3 s?1) might be necessary for elevated fresh submarine groundwater discharging (FSGD). Vertical profiles of salinity, DO and turbidity anomalies along the benthic boundary layer also indicated significant FSGD in the estuary during the WSRS. Nutrient concentrations had positive correlations with 222Rn during a 24-h observation, which indicates that SGD is a dominant nutrient pathway in this area

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

    International Nuclear Information System (INIS)

    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 ?mol m?2 d?1 and 92.8 ?mol m?2 d?1 for CH4 and N2O, respectively. - Highlights: • The estuary acts as a source of atmospheric methane and nitrous oxide. • Anthropogenic inputs affect the distribution of the greenhouse gases. • Dissolved gases presented an important longitudinal gradient. • Seasonal variations highly depended on the precipitation regimen

  2. Seasonal variation in sources and processing of particulate organic carbon in the Pearl River estuary, South China

    Science.gov (United States)

    Guo, Wei; Ye, Feng; Xu, Shendong; Jia, Guodong

    2015-12-01

    Particulate organic carbon (POC) in the Pearl River estuary (PRE), South China, along a salinity gradient from freshwater to seawater in four months was studied in order to determine its temporal and spatial changes in source and processing. Analytical parameters included chlorophyll-a (Chl-a), POC, and carbon isotopic composition of POC and the dissolved inorganic carbon (DIC) (?13CPOC, ?13CDIC). POC varied greatly from freshwater to seawater, exhibiting a significant power law distribution with a rapid decrease (from >2.5 mg l-1 to salinity range of 0-5 and then a slow decline to ?0.4 mg l-1 along the large salinity gradient in the estuary. POC was sourced predominantly from in situ phytoplankton, and hence largely reflective of primary production, in February, August, and November as indicated by mostly lower POC/Chl-a values (salinity estuarine water, as suggested by low POC% in total suspended substance, low Chl-a values and high POC/Chl-a ratios, and higher ?13CPOC values that was not in parallel with ?13CDIC excursion. The offset between ?13CPOC and phytoplankton ?13C (inferred from ?13CDIC) was trivial or positive in salinity <12, but then became negative downstream, which was likely suggestive of biogeochemical change from net respiration in the upper estuary to net production in the lower and outer estuary. Our results demonstrated that in situ phytoplankton was the dominant source to the estuarine POC pool during most seasons of a year, except in May in the first phase of wet season when rainfall and river flux increased abruptly causing intensive flushing effect. We further suggested that POC may be undergone intensive processing within the PRE, which is important for understanding organic carbon delivery in this vigorous land-ocean interface.

  3. 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-salinity relationship and laboratory mixing experiments demonstrated that dissolved Al has a non-conservative behavior in the Huanghe Estuary, where a significant loss (20-50%) occurred. The mechanism of removal of dissolved Al in the Huanghe Estuary was adsorption onto suspended particulate matter and salt-induced flocculation. These observations suggest that human activities (e.g. the WSRSs) and sorption processes dominate the geochemical interactions of Al in the Huanghe and its estuary.

  4. Cesium-137, metals and organic carbon in the sediments of the James River estuary, Virginia

    Science.gov (United States)

    Wong, George T. F.; Moy, Colin S.

    1984-01-01

    A wide variety of sedimentary subenvironments are found within a 10-km stretch of James River including a flood dominated channel (Rocklanding Channel) and its bank (Rocklanding Shoal), a shoal with a water depth of 1 m separating two channels (Point of Shoals), an ebb-dominated channel (Burwell Bay Channel) and its bank (Burwell Bay Bank) and a tributary (Warwick River). The concentrations of Cs-137, Cu, Pb, Zn and organic carbon in the fine-grained sediments (i.e. Cs-137 geochronology, range from 0·4 to > 3 cm year -1. The sedimentation rates in the Burwell Bay region are two or more, times those in the Point of Shoals and in the Rocklanding Channel and Shoal, reflecting the weaker currents in the Burwell Bay region. These sedimentation rates agree well with those obtained independently by measuring changes in the bathymetry of this area between 1873 and 1943. The concentrations of Cs-137, Cu, Pb, Zn and organic carbon in surface sediments vary by a factor of two to three. The concentrations are higher in the Burwell Bay region, probably as a result of the higher rates of accumulation of recently formed sediments in these subenvironments. The inventories of fine-grained sediments and of Cs-137, Cu, Pb, Zn and organic carbon accumulated since 1954 are also up to an order of magnitude higher in the Burwell Bay region. Although the concentrations of fine-grained sediments in three cores obtained in this region are similar, the inventories still vary by a factor of two to three. The inventories of Cs-137, Cu, Pb, Zn, organic carbon and fine-grained sediments correlate well with each other indicating that Cs-137 can be a useful tracer for studying the fate of these metals and organic carbon in estuarine environments. The inhomogeneity of the concentrations and inventories of the different elements along a 10-km segment of a river suggests that a closely-spaced sampling programme is essential for characterizing the sedimentary provinces within an estuary. The concentrations of Cs-137, metals and organic carbon in the coarse-grained sediments (i.e. > 63 ?m) are considerably lower than those in fine-grained sediments. Thus, the contribution of coarse-grained sediments to the total inventory of these elements is small.

  5. Historical trends of hypoxia in Changjiang River estuary: Applications of chemical biomarkers and microfossils

    Science.gov (United States)

    Li, Xinxin; Bianchi, Thomas S.; Yang, Zuosheng; Osterman, Lisa E.; Allison, Mead A.; DiMarco, Steven F.; Yang, Guipeng

    2011-06-01

    Over the past two decades China has become the largest global consumer of fertilizers, which has enhanced river nutrient fluxes and caused eutrophication and hypoxia in the Yangtze (Changjiang) large river delta-front estuary (LDE). In this study, we utilized plant pigments, lignin-phenols, stable isotopes (? 13C and ? 15N) and foraminiferal microfossils in 210Pb dated cores to examine the history of hypoxia in the Changjiang LDE. Two sediment cores were collected onboard R/V Dong Fang Hong 2 using a stainless-steel box-corer; one at a water depth of 24.7 m on Jun. 15, 2006 and the other at 52 m on Nov. 20, 2007, both in the hypoxic region off the Changjiang LDE. There has been a significant increase in the abundance of plant pigments after 1979 that are indicators of enhanced diatom and cyanobacterial abundance, which agrees with post-1980 record of increasing nutrient loads in the Changjiang River. The increased inputs of terrestrially derived materials to the LDE are largely woody plant sources and most likely due to deforestation that began in the early 1950s. However, post-1960 lignin data did not reflect enhanced loading of woody materials despite continued deforestation possibly due to increased trapping from greater dam construction, a reduction of deforestation in the drainage basin since the last 1990s, and soil conservation practices. The lack of linkages between bulk indices (stable isotopes, % OC, molar C/N ratios) and microfossil/chemical biomarkers may reflect relative differences in the amount of carbon tracked by these different proxies. Although NO 3- is likely responsible for most of the changes in phytoplankton production (post 1970s), historical changes in N loading from the watershed and hypoxia on the LDE shelf may not be as well linked in East China Sea (ECS) sediments due to possible denitrification/ammonification processes; finally, increases in low-oxygen tolerant foraminiferal microfossils indicate there has been an increase in the number of hypoxic bottom water events on the Changjiang LDE over the past 60 years.

  6. Historical trends of hypoxia in Changjiang River estuary: Applications of chemical biomarkers and microfossils

    Science.gov (United States)

    Li, X.; Bianchi, T.S.; Yang, Z.; Osterman, L.E.; Allison, M.A.; DiMarco, S.F.; Yang, G.

    2011-01-01

    Over the past two decades China has become the largest global consumer of fertilizers, which has enhanced river nutrient fluxes and caused eutrophication and hypoxia in the Yangtze (Changjiang) large river delta-front estuary (LDE). In this study, we utilized plant pigments, lignin-phenols, stable isotopes (?13C and ?15N) and foraminiferal microfossils in 210Pb dated cores to examine the history of hypoxia in the Changjiang LDE. Two sediment cores were collected onboard R/V Dong Fang Hong 2 using a stainless-steel box-corer; one at a water depth of 24.7 m on Jun. 15, 2006 and the other at 52 m on Nov. 20, 2007, both in the hypoxic region off the Changjiang LDE. There has been a significant increase in the abundance of plant pigments after 1979 that are indicators of enhanced diatom and cyanobacterial abundance, which agrees with post-1980 record of increasing nutrient loads in the Changjiang River. The increased inputs of terrestrially derived materials to the LDE are largely woody plant sources and most likely due to deforestation that began in the early 1950s. However, post-1960 lignin data did not reflect enhanced loading of woody materials despite continued deforestation possibly due to increased trapping from greater dam construction, a reduction of deforestation in the drainage basin since the last 1990s, and soil conservation practices. The lack of linkages between bulk indices (stable isotopes, % OC, molar C/N ratios) and microfossil/chemical biomarkers may reflect relative differences in the amount of carbon tracked by these different proxies. Although NO3? is likely responsible for most of the changes in phytoplankton production (post 1970s), historical changes in N loading from the watershed and hypoxia on the LDE shelf may not be as well linked in East China Sea (ECS) sediments due to possible denitrification/ammonification processes; finally, increases in low-oxygen tolerant foraminiferal microfossils indicate there has been an increase in the number of hypoxic bottom water events on the Changjiang LDE over the past 60 years.

  7. 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 lower limit allowed by the water-quality standard is 8 mg/L. Concentrations of dissolved oxygen measured in a cross section of the Puyallup River estuary at high tide on September 12, 2002, ranged from 9.9 to 10.2 mg/L in fresh water at the surface and from 8.1 to 8.4 mg/L in salt water near the riverbed. These values were within limits set by Washington State water-quality standards for dissolved oxygen of 8 mg/L in fresh water and 6 mg/L in marine water.

  8. 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 Thematic Mapper (TM) satellite imagery, making it feasible to assess land cover changes between 1992 and 2000.

  9. Estimation of the Probability of Long-Distance Dispersal: Stratified Diffusion of Spartina alterniflora in the Yangtze River Estuary

    Directory of Open Access Journals (Sweden)

    Wei Yang

    2014-11-01

    Full Text Available The relative contribution of long-distance dispersal and local diffusion in the spread of invasive species has been a subject of much debate. Invasion of the intertidal mudflats by Spartina alterniflora is an ideal example of stratified diffusion, involving both long-distance dispersal of seeds and local diffusion due to clonal growth. In conjunction with experimental data on range radius-versus-time curve, a traveling wave equation-based model is used to investigate the sensitivity of the spread rate of exotic S. alterniflora to parameters of long distance dispersal (c, maximum colonial establishment rate and local colony diffusion (r, intrinsic growth rate at two tidal marshes, the Eastern Chongming and the Jiuduansha Islands, at the Yangtze River estuary. Both Eastern Chong ming and Jiuduansha Islands are now national natural reserves in China, which were established in 2005. However, the mudflats and salt marshes in the two reserves are now heavily infested with introduced S. alterniflora, which may threaten the estuarine ecosystems and their biodiversity. S. alterniflora was first found in 1995 on Chongming. For rapid sediment accretion in mudflats in the estuary, S. alterniflora was also intentionally introduced to Jiuduansha in 1997 and Chongming in 2001, which has led to a rapid range expansion in the estuary. Our results show that range expansion of species with stratified diffusion is affected by both long-distance dispersal and local colony diffusion, and that there is a critical c*, below which the spread rate is more influenced by long-distance dispersal than by local diffusion. After applying this model to the invasion of S. alterniflora in the Yangtze River estuary, we derive that c = 1.7 × 10-3, c* = 0.126 and c = 4.8 × 10-3 km-2·yr-1, c* = 0.140 km-2·yr-1 at Chongming and Jiuduansha (Shanghai, respectively. Our results suggest that the range spread of S. alterniflora in the Yangtze River estuary is more influenced by long-distance dispersal than local colony diffusion, and that S. alterniflora generates about 1.7 × 10-3 to 4.8 × 10-3 colonies per square kilometers per year. This study provides important information about dispersal dynamics of S. alterniflora that may be useful for finding optimal control strategies. ·

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

    Science.gov (United States)

    Pang, A. P.; Sun, T.

    2014-05-01

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

  11. Integrated River and Coastal Hydrodynamic Flood Risk Mapping of the LaHave River Estuary and Town of Bridgewater, Nova Scotia, Canada

    Directory of Open Access Journals (Sweden)

    Tim Webster

    2014-03-01

    Full Text Available Bridgewater, Nova Scotia, is located 20 km inland from the mouth of the LaHave River estuary on the Atlantic Coast of Canada. Bridgewater is at risk of flooding due to the combined effects of river runoff and a storm surge on top of high tide. Projected increases in sea-level and possible increased river runoff with climate change increase the risk of future flooding. A set of river and ocean water level simulations were carried out to determine the risk of flooding to Bridgewater today and in the future under climate change. The hydrodynamic simulation developed incorporates return periods of a time series of river discharge measurements for the LaHave watershed, ocean water dynamics at the mouth of the river under normal tidal conditions and with two levels of storm surge, near shore and river bathymetry, as well as high precision topographic lidar derived ground elevations and survey grade GPS. The study was supported by data from two tide gauge sensors, and qualitative evidence provided by the community such as historical flood levels and photographs. Results show that areas upstream of the town are vulnerable to large discharge events of the LaHave River. The downtown waterfront and infrastructure are not susceptible to fluvial flooding, but is vulnerable to sea-level rise and storm surge flooding.

  12. Atmospheric nitrogen deposition to forest and estuary environments in the Pearl River Delta region, southern China

    Directory of Open Access Journals (Sweden)

    Xuemei Wang

    2013-09-01

    Full Text Available Due to its significant ecological and climate consequences, atmospheric nitrogen (N deposition is a growing global concern, especially in the severely N-polluted regions such as the Pearl River Delta (PRD region of southern China. One-year measurements of reactive N species, including ammonium nitrogen ( -N, nitrate nitrogen (-N and total organic nitrogen (ON in dry and wet deposition, were conducted using an automated wet–dry sampler incorporated with a DDAS (dry deposition on aqueous surface sampling device at Dinghushan (DHS, a natural forest site in the northwest of PRD and at Hengmen (HM, an estuary site in the south of PRD during 2006–2007. Total deposition fluxes of N at DHS and HM were up to 48.2 and 37.8 kg ha?1 yr?1, respectively, with most of the deposition occurring in the rainy season. Wet deposition was the dominant form, contributing 65–70% to the total deposition. -N was the largest contributor to the total N deposition at DHS (47% due to significant influence of agriculture emissions. ON was the most important N component at HM (41%, which is probably attributed to the marine sources. However, -N deposition is increasing rapidly recently and is expected to be more important in the near future. The current N deposition level in PRD is much higher than those in Europe and North America. Great challenges exist in reducing reactive N emission in this region. Thus, a scenario of rising N deposition in PRD in the near future cannot be ruled out. The environmental consequences due to elevated N deposition should therefore be paid more attention in the future.

  13. Arbuscular mycorrhizal relations of mangrove plant community at the Ganges river estuary in India.

    Science.gov (United States)

    Sengupta, Anjan; Chaudhuri, Subhendu

    2002-08-01

    Mangroves are climax formation of hydrohalophytes inhabiting estuarine or marine salt marshes in the tropics and subtropics. As a terrestrial plant community inhabiting tidally inundated estuarine or marine sediments, mangroves show considerable adaptation to salinity, water-logging and nutrient stress. Thirty-one species of mangrove and mangrove associates and 23 species of transported flora, belonging to 25 families at four physiographic stages of succession of the mangrove plant community at the terminal part of the Ganges river estuary in India were examined for arbuscular mycorrhizal (AM) root association. Dominant members of the mangrove plant community were all AM, mostly with 'Paris' type structures. Many of the known non-mycotrophic plant families, except the Cyperaceae, also showed AM association, with intracellular hyphae and vesicles as the most discernible endophyte structures. Intensity of AM colonization varied both with the species and situations of their occurrence, being more intense and also more extensive in less saline dry ridge mangroves than in more saline formative and developed swamp mangroves. Introduced exotic trees on the ridges and embankments were infected by AM, but less than the declining mangroves in the same location. Seven species of AM fungi in common with those of the upstream mesophytic plants were isolated from root-free rhizosphere soils of the mangroves, three of which predominated in root association. These species, individually and as mixtures, infected roots of salinity tolerant herbs and trees in both locational silt and upstream alluvial soil with obvious improvements in their biomass yield and phosphorus nutrition. AM infective potential of root-free rhizosphere soils of the dominant members of the mangrove community were negatively related to salinity level of the sediment soil of the successional stages. The evidences of AM association of mangroves and other salt marsh plants obtained here and those reported elsewhere are discussed. PMID:12189470

  14. Heavy metal and Pb isotopic compositions of aquatic organisms in the Pearl River Estuary, South China

    International Nuclear Information System (INIS)

    The accumulation of trace metals in aquatic organisms may lead to serious health problems through the food chain. The present research project aims to study the accumulation and potential sources of trace metals in aquatic organisms of the Pearl River Estuary (PRE). Four groups of aquatic organisms, including fish, crab, shrimp, and shellfish, were collected in the PRE for trace metal and Pb isotopic analyses. The trace metal concentrations in the aquatic organism samples ranged from 0.01 to 2.10 mg/kg Cd, 0.02 to 4.33 mg/kg Co, 0.08 to 4.27 mg/kg Cr, 0.15 to 77.8 mg/kg Cu, 0.17 to 31.0 mg/kg Ni, 0.04 to 30.7 mg/kg Pb, and 8.78 to 86.3 mg/kg Zn (wet weight). High concentrations of Cd were found in crab, shrimp and shellfish samples, while high concentration of Pb was found in fish. In comparison with the baseline reference values in other parts of the world, fish in the PRE had the highest elevated trace metals. The results of Pb isotopic compositions indicated that the bioaccumulation of Pb in fish come from a wide variety of food sources and/or exposure pathways, particularly the anthropogenic inputs. - Relative high concentrations of Cd were found in crab, shrimp and shellfish samples while high concentration of Pb was found in fish, particularly from the anthropogenic inputs

  15. An experimental study on major element release from the sediments in the Changjiang (Yangtze River) Estuary

    Science.gov (United States)

    Guo, Yanwei; Yang, Shouye

    2015-06-01

    With the enhanced warming and acidification of global ocean, whether and to what extent the naturally-weathered fluvial sediment into the sea can release elements and thus influence the geochemical process and ecosystem of global ocean remain to be resolved. In this contribution, an experimental study was carried out to examine the release rates of major elements (Ca, K, Mg and Al) from the surface sediments in the Changjiang (Yangtze River) Estuary under the pH values of 4.0, 6.0 and 7.0. The two studied sediments consist primarily of quartz, plagioclase, calcite and clay minerals, with the BET (Brunauer, Emmett and Teller) surface areas of 61.7 m2 g-1 and 23.1 m2 g-1. Major elements of Ca, K, Mg and Al show different release rates under different solution pH values. With the decreasing solution pH, the release rates of Ca and K increase obviously, while the release rates of Mg and Al increase with the initial solution pH varying from 6.0 to 7.0. The different release rates of these elements are closely related to the original mineral composition of the sediments and the reaction kinetics. Based on the experimental observation, quartz and clay minerals that have low dissolution rates may dominate the major element release to the aqueous phase. This study reveals that the enhancing ocean acidification could cause considerable release of major elements from natural terrigenous sediments into the ambient marine environment, which has to be considered carefully in the future study on global change.

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

    Science.gov (United States)

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

    2009-05-01

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

  17. 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.

  18. Use of fishing resources by women in the Mamanguape River Estuary, Paraíba state, Brazil

    Directory of Open Access Journals (Sweden)

    Michelle S.P. Rocha

    2012-12-01

    Full Text Available We evaluated the appropriation and use of fishing resources by women residing near the Mamanguape River Estuary (MRE, Paraíba state, Brazil. Were used combinations of qualitative (interviews and direct observations and quantitative methods (use value and corrected principal use concordance. Thirty women were interviewed and reported the use of 41 species (30 fish, 8 crustaceans, and 3 mollusks, mainly for local consumption and sale. The species with the highest use value were Genidens genidens (0.7, Callinectes exasperatus (0.73 and Anomalocardia brasiliana (0.46. The diversity of resources exploited demonstrates the importance of the mangrove ecosystem to MRE families, and the data gathered can serve as a basis for formulating public policies to promote the equal participation of women in fishing and environmental conservation.Nós analisamos a apropriação e o uso dos recursos pesqueiros pelas mulheres que moram no Estuário do Rio Mamanguape, Estado da Paraíba, Brasil. Foi usada uma combinação de métodos qualitativos (entrevistas e observações diretas e quantitativos (valor de uso e concordância de uso principal corrigido. Foram entrevistadas 30 mulheres e registrado o uso de 41 espécies (peixes - 30, crustáceos - 08 e moluscos - 03, principalmente para consumo local e venda. As espécies com maior valor de uso foram Genidens genidens (0,7, Callinectes exasperatus (0,73 e Anomalocardia brasiliana (0,46. A diversidade de recursos explorados demonstra a importância do manguezal para as famílias do ERM, e os dados coletados podem servir de base para a formulação de políticas públicas que promovam a participação igualitária de mulheres na pesca, e na conservação ambiental.

  19. 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. PMID:19139954

  20. Sources, distribution, and mobility of plutonium and radiocesium in soils, sediments and water of the Hudson River Estuary and watershed

    International Nuclear Information System (INIS)

    Results of 239240Pu, 238Pu and 137Cs measurements are reported for soil cores sampled within the watershed, for many sediment cores and surface dredge samples taken along the length of the Hudson River Estuary and for water samples collected on a continuous basis in both fresh and estuarine reaches. Accumulations of 239240Pu and 137Cs measured within sediment cores taken from discrete regions of the river-estuary were summed to arrive at total sediment inventories of 1.6 +/- 0.7 Ci and 53 +/- 20 Ci, respectively. The variability observed in the sediment accumulation of radionuclides is discussed in terms of the physical and chemical characteristics of the river-estuary. Plutonium-239,240 and 137Cs were similary distributed in sediments and water sampled from fresh water reaches of the Hudson with activity ratios (i.e., 239240Pu/12number7Cs) ranging from 0.01 to 0.03. Distribution coefficients, which were determined both in vitro and in situ were similar for both nuclides (i.e., from 1 x 105 to 3 x 105 L.kg-1) in fresh water, but diverged significantly (as a result of increased 137Cs solubility) in brackish waters that exhibited chlorinities in excess of 1-2 g Cl-.L-1. The concentrations of 239240Pu and 137Cs observed in fresh water samples were primarily functions of the suspended load. Approximately 60-70% of the annual downstream transport of 239240Pu and 137Cs calculated during 1980 and 1981 (i.e., 4 +/- 0.5 mCi and 515 +/- 84 mCi, respectively) was associated with suspended particulates greater than or equal to 0.45 ?m. An empirical model was developed to determine the rates of vertical migration of these nuclides in soils of the watershed

  1. A new species of Pseudodiaptomus (Crustacea, Copepoda, Calanoida, Pseudodiaptomidae) from the Prasae River Estuary, Gulf of Thailand

    OpenAIRE

    Khwanruan Srinui; Shuhei Nishida; Susumu Ohtsuka

    2013-01-01

    A new species of the calanoid copepod genus Pseudodiaptomus was collected from the Prasae River Estuary, Rayong Province, on the eastern coast of the Gulf of Thailand. This species is definitely assigned to the lobus species group sensu Walter (1986a). The female of the new species differs from other congeners in the elongate genital double-somite with a blunt process ventrally and the second urosomite about 2.54 times as long as wide. The male is also easily distinguished from other congener...

  2. Cadmium, manganese, nickel and lead contents in surface sediments of the lower Ulla River and its estuary (northwest Spain)

    OpenAIRE

    Prego, R.; Belzunce Segarra, María Jesús; Helios-Rybicka, E.; Barciela, Mª del Carmen

    1999-01-01

    [EN] The authors determined the total contents of cadmium, manganese, nickel and lead in 16 surface sediment samples along the last 7 km of the Ulla River and in its estuary. Prior to chemical analysis, the grain-size fractions below 500, 63 and 2 ?m were separated. The metal concentrations were analysed in the fraction below 63 ?m, and in selected samples from the clay fraction (< 2 ?m). The soil samples were digested with a HF + HNO3 + HCl mixture and the total concentrations ...

  3. Carbon dynamics of Deep Bay, eastern Pearl River Estuary, China. I: a mass balance budget and implications for shorebird conservation

    OpenAIRE

    Li, MS; Lee, SY

    1998-01-01

    Deep Bay is a shallow embayment (112 km2) in the eastern Pearl River Estuary, China, and comprises 4 major wetland components: (1) a shallow brackish water body of 2.9 m average depth, (2) 2700 ha of intertidal mudflat, (3) 200 ha of tidal mangroves and (4) 300 ha of traditional tidal aquaculture ponds excavated in the mid-to-high intertidal region. A carbon budget is proposed for Deep Bay based on published information on the 4 major landscape components. Despite the usual emphasis placed on...

  4. Nutrient fluxes in the Changjiang River estuary and adjacent waters — a modified box model approach

    Science.gov (United States)

    Wang, Xiaohong; Yu, Zhiming; Fan, Wei; Song, Xiuxian; Cao, Xihua; Yuan, Yongquan

    2015-01-01

    To solve nutrient flux and budget among waters with distinct salinity difference for water-salt-nutrient budget, a traditional method is to build a stoichiometrically linked steady state model. However, the traditional way cannot cope appropriately with those without distinct salinity difference that parallel to coastline or in a complex current system, as the results would be highly affected by box division in time and space, such as the Changjiang (Yangtze) River estuary (CRE) and adjacent waters (30.75°2-31.75°N, 122°10'-123°20'E). Therefore, we developed a hydrodynamic box model based on the traditional way and the regional oceanic modeling system model (ROMS). Using data from four cruises in 2005, horizontal, vertical and boundary nutrient fluxes were calculated in the hydrodynamic box model, in which flux fields and the major controlling factors were studied. Results show that the nutrient flux varied greatly in season and space. Water flux outweighs the nutrient concentration in horizontal flux, and upwelling flux outweighs upward diffusion flux in vertical direction (upwelling flux and upward diffusion flux regions overlap largely all the year). Vertical flux in spring and summer are much greater than that in autumn and winter. The maximum vertical flux for DIP (dissolved inorganic phosphate) occurs in summer. Additional to the fluxes of the Changjiang River discharge, coastal currents, the Taiwan Warm Current, and the upwelling, nutrient flux inflow from the southern Yellow Sea and outflow southward are found crucial to nutrient budgets of the study area. Horizontal nutrient flux is controlled by physical dilution and confined to coastal waters with a little into the open seas. The study area acts as a conveyer transferring nutrients from the Yellow Sea to the East China Sea in the whole year. In addition, vertical nutrient flux in spring and summer is a main source of DIP. Therefore, the hydrodynamic ROMS-based box model is superior to the traditional one in estimating nutrient fluxes in a complicated hydrodynamic current system and provides a modified box model approach to material flux research.

  5. Sciaenidae fish of the Caeté River estuary, Northern Brazil: mitochondrial DNA suggests explosive radiation for the Western Atlantic assemblage

    Directory of Open Access Journals (Sweden)

    Christina Vinson

    2004-01-01

    Full Text Available Sciaenids are fish which are normally abundant in tropical estuaries of the western Atlantic. Studies on the Caeté river estuary in the northern Brazilian state of Pará have revealed that in this area Sciaenidae is the dominant family, comprising almost 50% of all teleosts sampled. In this paper we present the results of the first phylogenetic study on South American estuarine sciaenids, during which we obtained mitochondrial gene 16S sequences from 15 species belonging to eight genera occurring in the Caeté estuary. Intergeneric nucleotide divergences varied from 5 to 15%, Lonchurus and Menticirrhus being the most divergent lineages. Nucleotide divergences were quite variable amongst species of the same genus, ranging from 1.2% (Stellifer microps x Stellifer naso to 8.4% (Menticirrhus americanus x Menticirrhus littoralis. Cladograms based on maximum parsimony, minimum evolution and maximum likelihood depicted an explosive diversification pattern for the western Atlantic sciaenid assemblage. Our analysis further reveals a very close relationship between Bairdiella and Stellifer, a monophyletic clade which emerged during the more recent diversification events of the Sciaenidae family. The phylogenetic reconstruction suggests the need for a revision of the taxonomy and nomenclature of the Bairdiella/Stellifer group.

  6. Sciaenidae fish of the Caeté River estuary, Northern Brazil: mitochondrial DNA suggests explosive radiation for the Western Atlantic assemblage

    Scientific Electronic Library Online (English)

    Christina, Vinson; Grazielle, Gomes; Horacio, Schneider; Iracilda, Sampaio.

    Full Text Available Sciaenids are fish which are normally abundant in tropical estuaries of the western Atlantic. Studies on the Caeté river estuary in the northern Brazilian state of Pará have revealed that in this area Sciaenidae is the dominant family, comprising almost 50% of all teleosts sampled. In this paper we [...] present the results of the first phylogenetic study on South American estuarine sciaenids, during which we obtained mitochondrial gene 16S sequences from 15 species belonging to eight genera occurring in the Caeté estuary. Intergeneric nucleotide divergences varied from 5 to 15%, Lonchurus and Menticirrhus being the most divergent lineages. Nucleotide divergences were quite variable amongst species of the same genus, ranging from 1.2% (Stellifer microps x Stellifer naso) to 8.4% (Menticirrhus americanus x Menticirrhus littoralis). Cladograms based on maximum parsimony, minimum evolution and maximum likelihood depicted an explosive diversification pattern for the western Atlantic sciaenid assemblage. Our analysis further reveals a very close relationship between Bairdiella and Stellifer, a monophyletic clade which emerged during the more recent diversification events of the Sciaenidae family. The phylogenetic reconstruction suggests the need for a revision of the taxonomy and nomenclature of the Bairdiella/Stellifer group.

  7. Distribution of submerged aquatic vegetation in the St. Louis River estuary: Maps and models (Presentation)

    Science.gov (United States)

    SAV provides the biophysical basis for several ecosystem services in Great Lakes estuaries including rearing and adult habitat for commercially and recreationally important fishes, foraging habit for waterfowl, and nutrient retention. Understanding sources of variation in SAV in ...

  8. Plutonium, radiocesium and radiocobalt in sediments of the Hudson River estuary

    International Nuclear Information System (INIS)

    Anthropogenic radionuclides have reached the Hudson estuary as global fallout from nuclear weapons testing and through local releases from commercial nuclear reactors. Significant activities of 238Pu and 239,240Pu (fallout-derived), 134Cs and 60Co (reactor-released), and 137Cs (derived from both sources), have accumulated in the sediments throughout the estuary, with the primary zone of accumulation near the downstream end of the system in New York harbor. The estuary appears to have trapped nearly all of the 239,240Pu delivered as fallout, and consequently, ocean dumping of dredged harbor sediment is currently the primary means for the net transport of these nuclides to coastal waters. In contrast, only 10-30% of the 137Cs, 134Cs and 60Co delivered to the estuary have been retained on the fine particles which accumulate at a rapid rate in the harbor. (orig./HAE)

  9. Inventories of 239240Pu, 241Am, 137Cs, and 60Co in Columbia River sediments from Hanford to the Columbia River estuary

    International Nuclear Information System (INIS)

    The inventories of 239240Pu, 241Am, 137Cs, and 60Co in sediments of the lower Columbia River and its estuary have been estimated from the measured activities of these radionuclides in 50 cores raised in 1977-1978. Cobalt-60 activities are attributed to the operation of the now inoperative plutonium production reactors located on the Hanford Reservation in Washington State; the majority of the 239240Pu and 137Cs activities and all of the 241Am activity are derived from global fallout. At the time of sampling, the operation of the Trojan nuclear power plant near St. Helens, OR, had not introduced detectable amounts of these radionuclides to the sandy sediments downstream from the plant location. Despite the substantial, past addition of artificial radioactivity to the river from the Hanford reactors, present inventories of artificial radioactivity are small. Erosional processes within the river's drainage basin remove negligible quantities of fallout radionuclides to the ocean. 31 references

  10. Infilling of the Hudson River Estuary During the Late Holocene (3000ka to Present): Implications for Estuarine Stratigraphic Models

    Science.gov (United States)

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

    2002-12-01

    Estuaries are widely preserved in the geologic record and the estuarine fill, contained between non-marine sediment, provides an excellent temporal marker for continental margin studies. Estuarine stratigraphic models have provided a framework within which to interpret the estuarine fill. However, estuarine systems differ greatly in the shape of their valleys, the tectonic boundaries they cross, and in sediment supply so that their position in the geologic record may be out of sequence with that predicted by the models. New insights into estuarine systems and models are provided by the Hudson River Estuary (HRE; New York State) based on >150 cores and grab sediment samples and acoustic images documenting in great detail how the HRE filled its earlier excavated valley during the latest Holocene (3ka to present). Radiocarbon and 137-Cs radioisotope ages, borehole, and core data document the sedimentation patterns of the estuary. Diatom assemblages provide estimates of the shallowing-upwards of the estuary as its basin filled with sediments. The three areas of the stratigraphic model present in the HRE, include zones formed within inner fluvial and outer marine areas, (containing coarse-grained, sands and gravels), and a central area (containing fine-grained, silts and clays), that are nearly filled with little room for sediments to accumulate at or near sea-level. This has resulted in sedimentary bypass for almost the entire length the estuary. South of Kingston, fine-grained sediments have ceased accumulating when the bottom approaches wave base. Upstream from Kingston, final filling occurs as sediments fill in the remaining accommodation, forming islands. This should result in the export of sediment to the coastal zone. Instead, localized areas of sediment trapping still exist, which are related to the Hudson Valley Highlands and to the location of the estuarine turbidity maximum that hold large volumes of sediment. As a result minor volumes of Recent sediment are accumulating in coastal bays (Sandy Hook, New Jersey) and on the inner shelf, and sediment export to the Hudson Shelf Valley on the mid-shelf is nearly non-existent, with sediments dated at 14ka from 14-C on the outer shelf. Additionally, anthropogenic activities (construction of bridges and dredging) alter sedimentation patterns in the estuary leading to continued localized erosion and deposition. For example, sediment export onto the shelf is taking place, not by natural processes but by dredging. The variability documented for the HRE indicates that although estuarine and stratigraphic models provide a framework for continental margin studies, the models need to be interpreted, taking into consideration these factors.

  11. 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, ?2 = 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.

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

    Scientific Electronic Library Online (English)

    José Mauro, Sterza; Luiz Loureiro, Fernandes.

    2006-12-01

    Full Text Available 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 salinidade e a temperatura. Foram identificadas dezessete espécies de cladóceros: 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 e Pleuroxus similis. As maiores abundâncias de cladóceros ocorreram no mês de abril na zona marinha do estuário. A espécie mais abundante nesse período foi Penilia avirostris. Na zona de mistura e fluvial do estuário, as espécies mais abundantes foram Moina micrura, principalmente durante o mês de janeiro; Simocephalus vetalus e Bosmina longirostris na primavera. Diante desse cenário, pode-se dizer que a comunidade de cladóceros no estuário do Rio Paraíba do Sul apresenta características de ambientes marinhos, estuarinos e limnicos. A salinidade e a temperatura parecem limitar a ocorrência e distribuição dos cladóceros no estuário. Abstract in english 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 pla [...] nkton 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.

  13. 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 salinidade e a temperatura. Foram identificadas dezessete espécies de cladóceros: 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 e Pleuroxus similis. As maiores abundâncias de cladóceros ocorreram no mês de abril na zona marinha do estuário. A espécie mais abundante nesse período foi Penilia avirostris. Na zona de mistura e fluvial do estuário, as espécies mais abundantes foram Moina micrura, principalmente durante o mês de janeiro; Simocephalus vetalus e Bosmina longirostris na primavera. Diante desse cenário, pode-se dizer que a comunidade de cladóceros no estuário do Rio Paraíba do Sul apresenta características de ambientes marinhos, estuarinos e limnicos. A salinidade e a temperatura parecem limitar a ocorrência e distribuição dos cladóceros no estuário.

  14. 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

    The restoration of wetland salmon habitat in the tidal portion of the Columbia River is occurring at an accelerating pace and is anticipated to improve habitat quality and effect hydrological reconnection between existing and restored habitats. Currently multiple groups are applying a variety of restoration strategies in an attempt to emulate historic estuarine processes. However, the region lacks both a standardized means of evaluating the effectiveness of individual projects as well as methods for determining the cumulative effects of all restoration projects on a regional scale. This project is working to establish a framework to evaluate individual and cumulative ecosystem responses to restoration activities in order to validate the effectiveness of habitat restoration activities designed to benefit salmon through improvements to habitat quality and habitat opportunity (i.e. access) in the Columbia River from Bonneville Dam to the ocean. The review and synthesis of approaches to measure the cumulative effects of multiple restoration projects focused on defining methods and metrics of relevance to the CRE, and, in particular, juvenile salmon use of this system. An extensive literature review found no previous study assessing the cumulative effects of multiple restoration projects on the fundamental processes and functions of a large estuarine system, although studies are underway in other large land-margin ecosystems including the Florida Everglades and the Louisiana coastal wetlands. Literature from a variety of scientific disciplines was consulted to identify the ways that effects can accumulate (e.g., delayed effects, cross-boundary effects, compounding effects, indirect effects, triggers and thresholds) as well as standard and innovative tools and methods utilized in cumulative effects analyses: conceptual models, matrices, checklists, modeling, trends analysis, geographic information systems, carrying capacity analysis, and ecosystem analysis. Potential 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.

  15. 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

  16. Collection and analysis of remotely sensed data from the Rhode River Estuary Watershed. [ecological parameters of Chesapeake Bay

    Science.gov (United States)

    Jenkins, D. W.

    1972-01-01

    NASA chose the watershed of Rhode River, a small sub-estuary of the Bay, as a representative test area for intensive studies of remote sensing, the results of which could be extrapolated to other estuarine watersheds around the Bay. A broad program of ecological research was already underway within the watershed, conducted by the Smithsonian Institution's Chesapeake Bay Center for Environmental Studies (CBCES) and cooperating universities. This research program offered a unique opportunity to explore potential applications for remote sensing techniques. This led to a joint NASA-CBCES project with two basic objectives: to evaluate remote sensing data for the interpretation of ecological parameters, and to provide essential data for ongoing research at the CBCES. A third objective, dependent upon realization of the first two, was to extrapolate photointerpretive expertise gained at the Rhode River watershed to other portions of the Chesapeake Bay.

  17. Looking for Damming Effects on the Sedimentation Rates in the Estuary Region of the Paraiba do Sul River, Brazil

    International Nuclear Information System (INIS)

    The objective of this work is to evaluate the sedimentation rates at Paraiba do Sul estuary and to correlate them with the strong erosion that occurs in Atafona, Rio de Janeiro. The coastal line of Atafona has been regressing in the last 50 years and the sea has destroyed some constructions. There are traces that one of the factors of the situation in Atafona is the disruption of the equilibrium deposition-erosion. The sedimentation rates will show the influence of the river material input and when it happened, enabling the evaluation of the human and natural impacts suffered by the river. The work was based on three transects, north, centre and south, where 10 sediment cores with about 350 sediment samples were collected in January 2010. The sedimentation rates were obtained based on 210Pb dating and the data validated based on the heavy metal profiles and the local anthropogenic impacts records. (author)

  18. 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. PMID:26178040

  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 water quality standards. It was observed that the water quality parameters in the Bonny Estuary show seasonal variation with higher values for pH, DO, BOD, temperature, and 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. An experimental transplantation to select the optimal site for restoration of the eelgrass Zostera marina in the Taehwa River estuary

    Science.gov (United States)

    Park, Jung-Im; Kim, Jeong Bae; Lee, Kun-Seop; Son, Min Ho

    2013-12-01

    To select the optimal site for the restoration of seagrass habitats in the Taehwa River estuary, we transplanted the eelgrass Zostera marina to three potential candidate sites in March 2007 and monitored the transplanted seagrass and associated environmental factors for six months. In all three sites, the transplanted seagrasses exhibited no initial morphological loss due to transplanting stress. The transplanted seagrass communities at sites 2 and 3 showed more than a 180% increase in density over the entire survey period. In contrast, despite a density increase in the first month after transplantation, most of the transplanted seagrasses at site 1 died. This may be due to the large decrease in underwater irradiance reaching the seagrass leaves at site 1 for two months during June and July, which fell below the level of compensation irradiance. The growth rate and size of the seagrass shoots were also larger at sites 2 and 3 compared with site 1. This is probably due to higher nutrient concentrations in the sediment pore water at sites 2 and 3 compared with site 1, although water depth, salinity, and the nutrient concentrations in the water columns from the three sites were similar. Therefore, for the restoration of seagrass habitats in the Taehwa River estuary, sites 2 and 3 were preferable to site 1 as transplantation sites.

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

    International Nuclear Information System (INIS)

    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 201 ng/g, with an average of 54.4 ng/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 210Pb 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. - The spatial and historical changes of Hg in sediment reflect the industrial development and urbanization of the region in south China.

  2. Distribuição de elementos tóxicos no estuário do rio Amazonas / Toxic elements distribution in the Amazon River estuary

    Scientific Electronic Library Online (English)

    Simone de Fátima Pinheiro, Pereira; Otílio Othon, Pires; Augusto Fonseca, Saraiva; Geiso Rafael, Oliveira; Pedro Moreira de, Sousa Junior; Rafaella Galvão, Miranda; Cleber Silva e, Silva; Reginaldo da Silva, Sales.

    Full Text Available A presença de elementos não essenciais nas águas superficiais do rio Amazonas é uma preocupação global, o objetivo da pesquisa foi estudar a distribuição dos elementos As, Al, Mn, e Pb na água do estuário do rio Amazonas. As amostras foram coletadas em três regiões distintas: Canal Norte (AP), Canal [...] Sul (PA) e rio Pará (PA) em três profundidades, com um total de 84 amostras. A espectrometria de emissão atômica com plasma indutivamente acoplado (ICPAES) foi utilizada para avaliar os teores de Al, Mn e Pb e a espectrofotometria de absorção atômica com geração de hidretos (HGAAS) foi usada para a análise do As. O As variou de Abstract in english The non-essential elements found in the superficial waters of the Amazon River is a global worry since the local hydric resources represent the world's largest fresh water reservoir. This research aimed at studying the occurrence of As, Al, Mn and Pb in the waters of the Amazon River estuary. The 84 [...] samples in three depths were collected in three different regions: North Channel of the Amazon River, in the state of Amapá; South Channel of the Amazon River, in the state of Pará; and Pará River, also in the state of Pará. Inductively coupled plasma atomic emission spectrometry (ICPAES) method was employed to determine the concentrations of Al, Mn and Pb in the samples while hydride generation atomic absorption spectrometry (HGAAS) method was employed in determining their As concentrations. As concentrations varied from

  3. 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)

  4. Extreme value analysis in typhoon prone areas: case study of the Pearl River estuary

    Science.gov (United States)

    Moerman, E.; de Graaff, R.; Rego, J. L.

    2014-12-01

    Extreme events such as tropical storms and typhoons are often the determining factor for the extreme values of wind, wave and water level conditions. The storm track, its propagation speed, the air pressure drop and the wind speed intensity of a typhoon determine the maximum occurring wave heights, water levels and currents. The stochastic behaviour of typhoons and tropical storms, however, lead to uncertainty in the extreme value analysis, because a slight variation of the typhoon track, propagation speed or wind speed intensity can have a significant impact on these local extreme hydrodynamic conditions. To determine the significance of the stochastic behaviour of typhoons a model assessment is performed comparing standard extreme value analysis values of measured water levels (e.g. values of 1/10, 1/50, and 1/100 year return periods) against model results of artificial typhoons. In the model assessment, making use of Delft3D, various artificial typhoons are modelled in which the typhoon tracks, propagation speeds and wind speed intensities are varied within realistic ranges (based on observed historical typhoons). The study focusses on the Pearl River estuary (China) where typically about 5 to 10 tropical storms or typhoons are observed every year. Once every few years an extreme typhoon hits the area. By quantifying the potential impact of artificial typhoons the uncertainty in the extreme water level values in such a typhoon prone area are better assessed. The model is validated simulating several historic typhoons. Subsequently the typhoons tracks, their propagation speeds and wind speed intensities are varied. The extreme water level values (extreme surge height + mean high water value) that follow from the artificial typhoon modelling are compared against values from a standard extreme value analysis, making use of the central limit theorem for the extreme values in a sample. A Peaks over Threshold approach is applied and the extremes are fitted and extrapolated according to a Generalized Pareto Distribution. One of our main conclusions is that while the peak surge heights and related total water levels resulting from the historical and synthetic typhoon simulations can exceed the once per 100 year extreme total water level estimates, they are generally within the 95% confidence interval of the estimate.

  5. The N-isotope effect and fractionation of nitrification in the tidal influenced Elbe River estuary, Germany

    Science.gov (United States)

    Sanders, Tina; Dähnke, Kirstin

    2014-05-01

    Estuaries act as a nutrient filter for coastal waters. The eutrophic Elbe River estuary is loaded with fertilizer-derived nitrogen, but management efforts have started to reduce this load effectively. However, an internal nitrate source in turn gained in importance and the estuary changed from a sink to a source of reactive nitrogen. Nitrification plays a key role in this estuarine nutrient regeneration but has to be quantified. The aim of our study was to assess the impact of nitrification on seasonal nitrogen loads and turnover using stable N- isotopes to identify the natural fractionation factor of nitrification. Therefor we measured the dissolved inorganic nitrogen (ammonium, nitrite and nitrate), their stable isotope signatures and the in-situ nitrification rates in the tidal influenced part of the river during 9 cruises from August 2011 to August 2013. The DIN load was higher in winter than in summer, the main compound was nitrate. In summer concentrations of nitrate entering the estuary were between 50 and 100 ?M and ?15N and ?18O were enriched to 15.5 to 21.5 o and 7.5 to 11.5 o respectively. Strong nitrification was found in the Hamburg port region. The nitrate concentrations increased significantly downstream after the port of Hamburg, along with a decrease of isotope values. Ammonium and nitrite peaked in the Hamburg port region with up to 25 ?M and 12 ?M, respectively. In July 2013, ?15N of ammonium has shown a mean value of 16.2±3.3 o and nitrite of -9.8±4.7 ‰The N-fractionation of nitrification in July 2013 was 15?nit -10o the sub-process ammonia oxidation 15?amox-24o and the nitrite oxidation of 15?niox 13o while fractionation was less pronounced during the other cruises Our data show that N-isotope fractionation generally confirmed culture experiments, but that it strongly depended on discharge, availability of substrate, temperature and the coupling of ammonia and nitrite oxidation.

  6. 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.

  7. 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.; Christoffersen, K.

    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 in...

  8. 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 presents classification results from analysis of the CASI imagery. Data sets produced for this project from both types of imagery fill a critical information gap by creating a current description of the condition and extent of estuarine habitat cover types along the lower Columbia River. Results from this study will be used by the Estuary Partnership and its cooperators to: (1) develop indicators of 'habitat health' and biological integrity; (2) develop definitions of 'critical salmonid habitat'; (3) identify and evaluate potential wetland conservation and restoration sites; (4) track exotic and invasive species; and (5) develop an understanding of how estuarine and riverine habitats have changed over the past 200 years. This study focuses on estuarine and riparian habitat cover types important to native species, particularly juvenile salmonids. This study is meant to provide support to the multiple efforts currently underway to recover 12 species of Columbia River salmonids identified as endangered or threatened under the Endangered Species Act.

  9. 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 13,600 cubic feet per second, respectively. On Front River, the maximum flood and ebb tides were –34,500 and 43,700 cubic feet per second, respectively; and on Union Creek, the maximum flood and ebb tides were –2,390 and 4,610 cubic feet per second, respectively. During the 5-month instrumentation deployment, computed tidal streamflows on Little Back River ranged from –7,820 to 9,600 cubic feet per second for the flood and ebb tides, respectively. On Middle River, the computed tidal streamflows ranged from –17,500 to 22,500 cubic feet per second for the flood and ebb tides, respectively. The computed tidal streamflows on Front River ranged from –78,900 to 87,200 cubic feet per second, and from –3,850 to 6,130 cubic feet per second on Union Creek for the flood and ebb tides, respectively. The streamgages on the Little Back, Middle, and Front Rivers have continued in operation following the initial 5-month deployment.

  10. 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 projects, these are reasonable success results and represent a small net gain in eelgrass in the LCRE. Crabs used both the eelgrass and unvegetated substrate, though in neither were there great abundance of the young-of-the-year crabs. During the field assessment of 12 potential transplant sites, divers discovered one site in southern Young's Bay that contained a previously undocumented eelgrass bed. This integrated project developed the first predictive maps of sites suitable for eelgrass and other SAV in the lower estuary. In addition, techniques developed for this project to assess light levels in existing and potential submerged habitats have great potential to be used in other regions for nearshore and coastal monitoring of SAV. Based on these preliminary results, we conclude that eelgrass distribution could likely be expanded in the estuary, though additional information on current eelgrass locations, usage by species of interest, and monitoring of current conditions would help develop a baseline and verify benefit. Our recommendations for future studies include: (1) Site Monitoring. Continued monitoring of restoration sites along with physical metrics of light, temperature and salinity within beds. Continued monitoring will both assist managers in understanding the longevity and expansion rate of planted sites and inform practical guidance on the minimum planted eelgrass required to develop a resilient meadow. (2) Natural bed documentation and monitoring. Document current eelgrass habitat conditions in the Columbia River by mapping eelgrass and other SAV species and monitoring physical metrics in natural beds. This will assist by better defining the factors that control the annual and spatial variation in eelgrass in the estuary, and thus lead to improved management. Improved information on conditions will help refine a habitat suitability model that can more accurately predict where eelgrass can be restored or areas under duress. (3) Monitor Species Use. Expanded monitoring of Dungeness crab and salmon use and benefit from eelgrass in the estuary to evaluate how feeding and rearing functions of eelgrass benefit the survival and growth of these species. We have two final recommendations. First, if transplanting of eelgrass is to be expanded, donor stocks of plants should also be expanded to reduce the dependence on natural meadows. We recommend that an eelgrass culture facility be considered to supply stocks of eelgrass for planting that are developed from the eelgrass populations now in the estuary. Second, freshwater submerged aquatic vegetation (SAV) occurs in many parts of the estuary, and probably has importance to juvenile salmon (although this also needs verification). Restoration and expansion of freshwater SAV should be considered in a comprehensive effort to restore the submerged vegetation habitats through the Columbia River estuary.

  11. Mercury in bottom sediments of the Amur River, its flood-plain lakes and estuary, Eastern Siberia.

    Science.gov (United States)

    Kot, Fyodor S; Bakanov, Konstantin G; Goryachev, Nikolay A

    2010-09-01

    Mercury (Hg) is an element of a special concern in the Amur River basin, where numerous cinnabar deposits and manifestations have been prospected. Moreover, the territory is under heavy anthropogenic pressure due to intensive economic development that includes activities accompanied by noticeable emissions of Hg to the environment through poor waste management practices and accidental emergency discharges. Yet, information on Hg distribution and behavior in this region is scarce and inadequate. In order to evaluate Hg levels and fate in this vast territory, surveys of river, lake, and estuarine bottom sediments, as integral indicators of environmental status, were carried out in 1990, 1991, 1997, and 2004. The results showed the following: (1) stagnation of the Russian economy in the 1990s has resulted in a noticeable decrease of the Hg content in the Amur River sediments to the basin pristine level of about 0.05 mg kg(-1); (2) Hg distribution in the sediment depth proves the element redox-dependent behavior; (3) in some cases, Hg enrichment may be related to the long-term anthropogenic emission; (4) Hg concentration in bottom sediments was found to increase in the following order-the Amur River mouth, the estuary, and the Sea of Okhotsk, showing the weakly non-conservative Hg behavior during estuarine water mixing. PMID:19629736

  12. Evaluation of the ecotoxicity of sediments from Yangtze river estuary and contribution of priority PAHs to ah receptor--mediated activities.

    Science.gov (United States)

    Liu, Li; Chen, Ling; Shao, Ying; Zhang, Lili; Floehr, Tilman; Xiao, Hongxia; Yan, Yan; Eichbaum, Kathrin; Hollert, Henner; Wu, Lingling

    2014-01-01

    In this study, in vitro bioassays were performed to assess the ecotoxicological potential of sediments from Yangtze River estuary. The cytotoxicity and aryl hydrocarbon receptor (AhR)-mediated toxicity of sediment extracts with rainbow trout (Oncorhynchus mykiss) liver cells were determined by neutral red retention and 7-ethoxyresorufin-O-deethylase assays. The cytotoxicity and AhR-mediated activity of sediments from the Yangtze River estuary ranged from low level to moderate level compared with the ecotoxicity of sediments from other river systems. However, Yangtze River releases approximately 14 times greater water discharge compared with Rhine, a major river in Europe. Thus, the absolute pollution mass transfer of Yangtze River may be detrimental to the environmental quality of estuary and East China Sea. Effect-directed analysis was applied to identify substances causing high dioxin-like activities. To identify unknown substances contributing to dioxin-like potencies of whole extracts, we fractionated crude extracts by open column chromatography. Non-polar paraffinic components (F1), weakly and moderately polar components (F2), and highly polar substances (F3) were separated from each crude extract of sediments. F2 showed the highest dioxin-like activities. Based on the results of mass balance calculation of chemical toxic equivalent concentrations (TEQs), our conclusion is that priority polycyclic aromatic hydrocarbons indicated a low portion of bio-TEQs ranging from 1% to 10% of crude extracts. Further studies should be conducted to identify unknown pollutants. PMID:25111307

  13. Phytotoxicity of surface waters of the Thames and Brisbane River estuaries: a combined chemical analysis and bioassay approach for the comparison of two systems.

    Science.gov (United States)

    Bengtson Nash, S M; Goddard, J; Müller, J F

    2006-05-15

    The Thames Estuary, UK, and the Brisbane River, Australia, are comparable in size and catchment area. Both are representative of the large and growing number of the world's estuaries associated with major cities. Principle differences between the two systems relate to climate and human population pressures. In order to assess the potential phytotoxic impact of herbicide residues in the estuaries, surface waters were analysed with a PAM fluorometry-based bioassay that employs the photosynthetic efficiency (photosystem II quantum yield) of laboratory cultured microalgae, as an endpoint measure of phytotoxicity. In addition, surface waters were chemically analysed for a limited number of herbicides. Diuron, atrazine and simazine were detected in both systems at comparable concentrations. In contrast, bioassay results revealed that whilst detected herbicides accounted for the observed phytotoxicity of Brisbane River extracts with great accuracy, they consistently explained only around 50% of the phytotoxicity induced by Thames Estuary extracts. Unaccounted for phytotoxicity in Thames surface waters is indicative of unidentified phytotoxins. The greatest phytotoxic response was measured at Charing Cross, Thames Estuary, and corresponded to a diuron equivalent concentration of 180 ng L(-1). The study employs relative potencies (REP) of PSII impacting herbicides and demonstrates that chemical analysis alone is prone to omission of valuable information. Results of the study provide support for the incorporation of bioassays into routine monitoring programs where bioassay data may be used to predict and verify chemical contamination data, alert to unidentified compounds and provide the user with information regarding cumulative toxicity of complex mixtures. PMID:16314084

  14. 78 FR 23746 - Takes of Marine Mammals Incidental to Specified Activities; Russian River Estuary Management...

    Science.gov (United States)

    2013-04-22

    ...number of management events during...low in the past, and the...monitoring data, harbor seals...during estuary management activities...in the years since appropriate...historical data. The average...in recent years during that...the lagoon management period, the...Based on past...

  15. 78 FR 14985 - Takes of Marine Mammals Incidental to Specified Activities; Russian River Estuary Management...

    Science.gov (United States)

    2013-03-08

    ...March in the past 10 years. Potential...monitoring data exists for...regular estuary management activity...operations, past monitoring...historical data. The average...in recent years during that...the lagoon management period...Based on past...

  16. 77 FR 24471 - Takes of Marine Mammals Incidental to Specified Activities; Russian River Estuary Management...

    Science.gov (United States)

    2012-04-24

    ...number of management events during...low in the past, and the...monitoring data, harbor seals...during estuary management activities...in the years since appropriate...historical data. The average...in recent years during that...the lagoon management period, the...Based on past...

  17. 77 FR 15722 - Takes of Marine Mammals Incidental to Specified Activities; Russian River Estuary Management...

    Science.gov (United States)

    2012-03-16

    ...March in the past 10 years. Potential...monitoring data exists for...regular estuary management activity...operations, past monitoring...historical data. The average...in recent years during that...the lagoon management period...Based on past...

  18. High CO2 emissions from the tropical Godavari estuary (India) associated with monsoon river discharges

    Digital Repository Service at National Institute of Oceanography (India)

    Sarma, V.V.S.S.; Kumar, N.A.; Prasad, V.R.; Venkataramana, V.; Appalanaidu, S.; Sridevi, B.; Kumar, B.S.K.; Bharati, M.D.; Subbaiah, C.V; Acharyya, T.; Rao, G.D.; Viswanadham, R.; Gawade, L.; Manjary, D.T.; Kumar, P.P.; Rajeev, K.; Reddy, N.P.C.; Sarma, V.V.; Kumar, M.D.; Sadhuram, Y.; Murty, T.V.R.

    (25.72 mol C m -2 y -1 or 0.173 TgC y -1 ) for entire tropical and subtropical band by Borges et al. (2005). Several estuaries, major and minor, open into the northern Indian Ocean and creation of conditions observed in this study would make...

  19. 78 FR 23746 - Takes of Marine Mammals Incidental to Specified Activities; Russian River Estuary Management...

    Science.gov (United States)

    2013-04-22

    ... of reducing flood risk. There are three components to SCWA's ongoing estuary management activities... accomplish the dual purposes of flood risk abatement and maintenance of juvenile salmonid habitat; (2) traditional artificial breaching, with the sole objective of flood risk abatement; and (3) physical...

  20. 77 FR 24471 - Takes of Marine Mammals Incidental to Specified Activities; Russian River Estuary Management...

    Science.gov (United States)

    2012-04-24

    ... breaches of barrier beach may be conducted for the sole purpose of reducing flood risk. There are three... lagoon management period only, required to accomplish the dual purposes of flood risk abatement and... flood risk abatement; and (3) physical and biological monitoring in and near the estuary, required...

  1. 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.

  2. 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 infecting oysters C. rhizophorae whose pathogenic potential is unknown. PMID:23147104

  3. Plutonium, radiocesium and radiocobalt in sediments of the Hudson River estuary

    Science.gov (United States)

    Olsen, C. R.; Simpson, H. J.; Trier, R. M.

    1981-11-01

    Anthropogenic radionuclides have reached the Hudson estuary as global fallout from nuclear weapons testing and through local releases from commercial nuclear reactors. Significant activities of 238Pu and 239,240Pu (fallout-derived), 134Cs and 60Co (reactor-released), and 137Cs (derived from both sources), have accumulated in the sediments throughout the estuary, with the primary zone of accumulation near the downstream end of the system in New York harbor. The estuary appears to have trapped nearly all of the 239,240Pu delivered as fallout, and consequently, ocean dumping of dredged harbor sediment is currently the primary means for the net transport of these nuclides to coastal waters. In contrast, only 10-30% of the 137Cs, 134Cs and 60Co delivered to the estuary have been retained on the fine particles which accumulate at a rapid rate in the harbor. The primary factors which have governed the distribution of anthropogenic radionuclides in Hudson sediments are: (1) spread of fine particles labeled with both fallout and reactor nuclides throughout the axis of the estuary, (2) differences in timing of the peak fallout years (1962-1964) and years of maximum reactor releases (1971-1972), (3) large variations in sediment accumulation rates, ranging from a few millimeters per year or less to many tens of centimeters per year, (4) appreciable desorption of 137Cs and 134Cs from particles at higher salinities, and (5) possible enhanced desorption of 60Co at higher salinities (relative to 134Cs and 137Cs) which may be associated with the release of reduced manganese from the harbor sediments.

  4. The distribution of nitrogen species and adsorption of ammonium in sediments from the tidal Potomac River and estuary

    Science.gov (United States)

    Simon, N.S.; Kennedy, M.M.

    1987-01-01

    The distribution of dissolved ammonium, adsorbed ammonium and residual, organic and total nitrogen was measured in Potomac River tidal, transition zone and lower estuary sediments to a depth of 66 cm. For these sediments, exchangeable ammonium, and thereby adsorbed ammonium concentrations, were determined directly using an ammonia electrode in alkaline sediment suspensions. Ammonia electrode data were comparable to data obtained by KCl extraction of fresh sediment. The conventional unitless ammonium adsorption coefficient, calculated as the slope of the regression line drawn when sediment-adsorbed ammonium (??mol g-1 dry wt of sediment) is plotted against interstitial water ammonium (??mol g-1 dry wt sediment), is 1??5 for this system. When a modified ammonium adsorption coefficient is calculated from sediment-adsorbed ammonium concentrations and a ratio of interstitial water ammonium and potassium concentrations, the regression equation through the data has a zero intercept and is more nearly linear than the regression equation of data based on conventional calculations. The use of a ratio including ammonium and potassium concentrations in the interstitial water term takes into account ionic strength variations in the estuary and competition between ammonium and potassium for adsorption sites. ?? 1987.

  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 (?(199)Hg: +0.05 ± 0.10‰ to +0.59 ± 0.30‰) with a ?(199)Hg/?(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 ?(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. PMID:26766353

  6. 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 a combination of bathymetry and ecological boundaries within LPRE. Regardless of their reproductive condition, females showed a strong fidelity to IL, and their foraging activity was restricted to relatively shallow areas (10-100 m) on the continental shelf. During autumn and winter, SSL females made significantly longer FTs than during the breeding season, when lactating females decrease FT duration by increasing transit speed but maintain a similar spatial coverage compared with FT later in lactation. Although several aquatic areas of high priority for conservation in LPRE have been identified and proposed, only 15% of the foraging habitat of SSL females is currently included in these areas. This emphasizes the importance of the inclusion of the at-sea foraging distributions of central point foragers in marine protected areas. If conservation efforts focus only on coastal breeding concentrations, key elements of the life cycle are excluded with potential unpredictable effects.

  7. 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 matter (CDOM) vs. CHL in submarine light availability throughout the CRE, assess if reductions in nutrient loads are more feasible by controlling freshwater quantity or N and P concentrations, and explore the role of inflow and flushing on the fates of externally and internally derived dissolved and particulate constituents.

  8. 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.

  9. The 137Cs distribution in sediment profiles from the Yangtze River estuary: a comparison of modeling and experimental results

    International Nuclear Information System (INIS)

    It has been generally accepted when estimating sedimentation rates using the 137Cs dating method that the position of the 137Cs maximum in a sediment profile represents the year 1963. In this paper we validated this approach by developing a model in which the annual 137Cs global fallout flux for the Yangtze River estuary was established on the basis of the Tokyo flux corrected for precipitation rates observed in Shanghai. As the 137Cs maxima in the sediment deposition profiles depend on the sedimentation rates, the sub-sampling intervals were calculated accordingly. Higher measured than the calculated values were found in some cores, what may be due to fluctuating sedimentation rates and an additional deposition of 137Cs from land-based sources. The study provides useful information on the reliability of the measured 137Cs maxima in sediment profiles frequently used for dating of sediments in marine (coastal regions, open seas) as well as in terrestrial (lakes) environments. (author)

  10. Simulation Study on the Effect of Sand Digging and Heaping on SAR Imaging in the Pearl River Estuary

    Science.gov (United States)

    Wang, X.; Zhang, H.; Fu, B.; Guan, W.; Shi, A.

    2013-07-01

    There are frequent sand digging and heaping activities in shoal in the Pearl River Estuary (PRE). Water depth has changed in patches, which can be imaged by synthetic aperture radar (SAR). According to SAR imaging mechanism of underwater bathymetry, a 3-D hydrodynamic model is used to demonstrate the temporal variations of the shoal topography changes due to sand digging and heaping. A microwave radar imaging of oceanic surface's program is used to simulate the variation of normalized radar cross section (NRCS) induced by the ocean surface current. The simulation is carried out to study the digging-heaping shape, water depth changes on SAR imaging of shoal bathymetry. Results indicate several points as followings. 1. Circle-shaped sand digging and heaping are imaged clearer by SAR than other shapes. 2. Sand heaping has a greater effect on SAR imaging than sand digging. 3. Bigger depth change induces bigger NRCS variation.

  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 ( P<0.05). In sediment, only Cr varied significantly ( p<0.05) within the two years. Bioaccumulation 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. Biological effects of simulated discharge plume entrainment at Indian Point Nuclear Power Station, Hudson River estuary, USA

    International Nuclear Information System (INIS)

    Laboratory and field simulations of the discharge plume entrainment of phytoplankton, zooplankton and fish were carried out at the Indian Point Nuclear Station, Hudson River estuary, USA. Phytoplankton assemblages studied on two dates produced different response patterns measured as photosynthetic activity. Chlorophyll-a levels did not change following simulated entrainment. Possible explanations for the differences are discussed. The two abundant copepods Acartia tonsa and Eurytemorta affinis appear to tolerate exposure to discharge plume ?T without adverse effects. Copepods subjected to plume entrainment may suffer considerable mortality during periods of condenser chlorination. In general, the amphipod Gammarus spp. did not appear to suffer significant mortality during simulated entrainment. Juvenile striped bass, Morone saxatilis, were not affected by simulated plume transit before and during plant condenser chlorination; however, a simulated ''worst possible case'' plume ?T produced statistically significant moralities. (author)

  13. A new species of Pseudodiaptomus (Crustacea, Copepoda, Calanoida, Pseudodiaptomidae from the Prasae River Estuary, Gulf of Thailand

    Directory of Open Access Journals (Sweden)

    Khwanruan Srinui

    2013-10-01

    Full Text Available A new species of the calanoid copepod genus Pseudodiaptomus was collected from the Prasae River Estuary, Rayong Province, on the eastern coast of the Gulf of Thailand. This species is definitely assigned to the lobus species group sensu Walter (1986a. The female of the new species differs from other congeners in the elongate genital double-somite with a blunt process ventrally and the second urosomite about 2.54 times as long as wide. The male is also easily distinguished from other congeners by the structure of the right fifth leg.The present new species is a euryhaline species and occurred in brackish waters with salinity ranging from 0.7 to 23.3. Its breeding season may be from June to October, as indicated by the presence of egg-sacs.

  14. A new species of Pseudodiaptomus (Crustacea, Copepoda, Calanoida, Pseudodiaptomidae) from the Prasae River Estuary, Gulf of Thailand.

    Science.gov (United States)

    Srinui, Khwanruan; Nishida, Shuhei; Ohtsuka, Susumu

    2013-01-01

    A new species of the calanoid copepod genus Pseudodiaptomus was collected from the Prasae River Estuary, Rayong Province, on the eastern coast of the Gulf of Thailand. This species is definitely assigned to the lobus species group sensu Walter (1986a). The female of the new species differs from other congeners in the elongate genital double-somite with a blunt process ventrally and the second urosomite about 2.54 times as long as wide. The male is also easily distinguished from other congeners by the structure of the right fifth leg. The present new species is a euryhaline species and occurred in brackish waters with salinity ranging from 0.7 to 23.3. Its breeding season may be from June to October, as indicated by the presence of egg-sacs. PMID:24146583

  15. 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.

  16. Relationships between pesticides and organic carbon fractions in sediments of the Danshui River estuary and adjacent coastal areas of Taiwan

    International Nuclear Information System (INIS)

    In order to understand the fate of pesticides in marine environments, concentrations of pesticides and different carbonaceous fractions were determined for surface sediments in the Danshui River and nearby coastal areas of Taiwan. The major compounds detected were tetrachlorobenzene, HCHs, chlordane, aldrin, DDDs, DDEs and DDTs. Total concentrations of pesticides in the sediments ranged from not detectable to 23 ng g-1, with the maximum value detected near the discharge point of the marine outfall from the Pali sewage treatment plant. These results confirm that pesticides persist in estuarine and nearby coastal environments of the Danshui River well after their ban. Concentrations of total pesticides significantly correlate with concentrations of total organic carbon and black carbon in these sediments, suggesting that total organic carbon and black carbon regulate the distribution of trace organic pollutants in fluvial and coastal marine sediments. - Total organic carbon and black carbon regulate the distribution of trace organic pollutants in sediments of the Danshui River estuary and adjacent coastal areas of Taiwan

  17. Fish community changes in the St. Louis River estuary, Lake Superior, 1989-1996: Is it ruffe or population dynamics?

    Science.gov (United States)

    Bronte, Charles R.; Evrard, Lori M.; Brown, William P.; Mayo, Kathleen R.; Edwards, Andrew J.

    1998-01-01

    Ruffe (Gymnocephalus cernuus) have been implicated in density declines of native species through egg predation and competition for food in some European waters where they were introduced. Density estimates for ruffe and principal native fishes in the St. Louis River estuary (western Lake Superior) were developed for 1989 to 1996 to measure changes in the fish community in response to an unintentional introduction of ruffe. During the study, ruffe density increased and the densities of several native species decreased. The reductions of native stocks to the natural population dynamics of the same species from Chequamegon Bay, Lake Superior (an area with very few ruffe) were developed, where there was a 24-year record of density. Using these data, short- and long-term variations in catch and correlations among species within years were compared, and species-specific distributions were developed of observed trends in abundance of native fishes in Chequamegon Bay indexed by the slopes of densities across years. From these distributions and our observed trend-line slopes from the St. Louis River, probabilities of measuring negative change at the magnitude observed in the St. Louis River were estimated. Compared with trends in Chequamegon Bay, there was a high probability of obtaining the negative slopes measured for most species, which suggests natural population dynamics could explain, the declines rather than interactions with ruffe. Variable recruitment, which was not related to ruffe density, and associated density-dependent changes in mortality likely were responsible for density declines of native species.

  18. The diverse species of the genus Hantzschia (Bacillariophyta in sand flats of the Nakdong River estuary in Korea

    Directory of Open Access Journals (Sweden)

    Gyeongje Joh

    2014-12-01

    Full Text Available To collect the diatom species belonging to the genus Hantzschia, bottom sediments were collected from 32 sampling sites in 23 sand-flat areas in the intertidal zone and river reaches of Nakdong River estuary, Korea. The sand sediments contained a total of 19 species of genus Hantzschia, Hantzschia amphioxys (Ehrenberg Grunow, H. amphioxys f. capitata O. Müller, H. baltica Simonsen, H. distinctepunctata (Hustedt Hustedt, H. elegantula (Østrup Witkowski et al., H. longiareolata Garcia-Baptista, H. marina (Donkin Grunow, H. pseudomarina Hustedt, H. virgata (Roper Grunow, H. virgata var. gracilis Hustedt, H. virgata var. kariana Grunow, H. virgata var. leptocephala Østrup and H. weyprechtii Grunow, including six unconfirmed species. Eleven Hantzschia species are reported as new to Korea. Hantzschia virgata, its infraspecies, and neighboring speceis showed large morphological variations within a single species or among the closely related species. Hantzschia amphioxys, H. distinctepunctata, and H. virgata var. leptocephala prefer freshwater habitats in the upper reaches of the river, while others occurred mainly in the sand flats composed of coarse sand in the intertidal area. In the estuarine sediments, the Hantzschia taxa are classified to be typical sand-attached forms.

  19. Long-term effects of changing land use practices on surface water quality in a coastal river and lagoonal estuary.

    Science.gov (United States)

    Rothenberger, Meghan B; Burkholder, JoAnn M; Brownie, Cavell

    2009-09-01

    The watershed of the Neuse River, a major tributary of the largest lagoonal estuary on the U.S. mainland, has sustained rapid growth of human and swine populations. This study integrated a decade of available land cover and water quality data to examine relationships between land use changes and surface water quality. Geographic Information Systems (GIS) analysis was used to characterize 26 subbasins throughout the watershed for changes in land use during 1992-2001, considering urban, agricultural (cropland, animal as pasture, and densities of confined animal feed operations [CAFOs]), forested, grassland, and wetland categories and numbers of wastewater treatment plants (WWTPs). GIS was also used together with longitudinal regression analysis to identify specific land use characteristics that influenced surface water quality. Total phosphorus concentrations were significantly higher during summer in subbasins with high densities of WWTPs and CAFOs. Nitrate was significantly higher during winter in subbasins with high numbers of WWTPs, and organic nitrogen was higher in subbasins with higher agricultural coverage, especially with high coverage of pastures fertilized with animal manure. Ammonium concentrations were elevated after high precipitation. Overall, wastewater discharges in the upper, increasingly urbanized Neuse basin and intensive swine agriculture in the lower basin have been the highest contributors of nitrogen and phosphorus to receiving surface waters. Although nonpoint sources have been emphasized in the eutrophication of rivers and estuaries such as the Neuse, point sources continue to be major nutrient contributors in watersheds sustaining increasing human population growth. The described correlation and regression analyses represent a rapid, reliable method to relate land use patterns to water quality, and they can be adapted to watersheds in any region. PMID:19597872

  20. 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.

  1. Long-Term Effects of Changing Land Use Practices on Surface Water Quality in a Coastal River and Lagoonal Estuary

    Science.gov (United States)

    Rothenberger, Meghan B.; Burkholder, Joann M.; Brownie, Cavell

    2009-09-01

    The watershed of the Neuse River, a major tributary of the largest lagoonal estuary on the U.S. mainland, has sustained rapid growth of human and swine populations. This study integrated a decade of available land cover and water quality data to examine relationships between land use changes and surface water quality. Geographic Information Systems (GIS) analysis was used to characterize 26 subbasins throughout the watershed for changes in land use during 1992-2001, considering urban, agricultural (cropland, animal as pasture, and densities of confined animal feed operations [CAFOs]), forested, grassland, and wetland categories and numbers of wastewater treatment plants (WWTPs). GIS was also used together with longitudinal regression analysis to identify specific land use characteristics that influenced surface water quality. Total phosphorus concentrations were significantly higher during summer in subbasins with high densities of WWTPs and CAFOs. Nitrate was significantly higher during winter in subbasins with high numbers of WWTPs, and organic nitrogen was higher in subbasins with higher agricultural coverage, especially with high coverage of pastures fertilized with animal manure. Ammonium concentrations were elevated after high precipitation. Overall, wastewater discharges in the upper, increasingly urbanized Neuse basin and intensive swine agriculture in the lower basin have been the highest contributors of nitrogen and phosphorus to receiving surface waters. Although nonpoint sources have been emphasized in the eutrophication of rivers and estuaries such as the Neuse, point sources continue to be major nutrient contributors in watersheds sustaining increasing human population growth. The described correlation and regression analyses represent a rapid, reliable method to relate land use patterns to water quality, and they can be adapted to watersheds in any region.

  2. Estimation of chlorophyll-a concentration in estuarine waters: case study of the Pearl River estuary, South China Sea

    International Nuclear Information System (INIS)

    The objective of this work is to estimate chlorophyll-a (chl-a) concentration in the Pearl River estuary in China. To test the performance of algorithms for the estimation of the chl-a concentration in these productive turbid waters, the maximum band ratio (MBR) and near-infrared-red (NIR-red) models are used in this study. Specific focus is placed on (a) comparing the ability of the models to estimate chl-a in the range 1-12 mg m-3, which is typical for coastal and estuarine waters, and (b) assessing the potential of the Moderate Resolution Imaging Spectrometer (MODIS) and Medium Resolution Imaging Spectrometer (MERIS) to estimate chl-a concentrations. Reflectance spectra and water samples were collected at 13 stations with chl-a ranging from 0.83 to 11.8 mg m-3 and total suspended matter from 9.9 to 21.5 g m-3. A close relationship was found between chl-a concentration and total suspended matter concentration with the determining coefficient (R2) above 0.89. The MBR calculated in the spectral bands of MODIS proved to be a good proxy for chl-a concentration (R2 > 0.93). On the other hand, both the NIR-red three-band model, with wavebands around 665, 700, and 730 nm, and the NIR-red two-band model (with bands around 665 and 700 nm) explained more than 95% of the chl-a variation, and we were able to estimate chl-a concentrations with a root mean square error below 1 mg m-3. The two- and three-band NIR-red models with MERIS spectral bands accounted for 93% of the chl-a variation. These findings imply that the extensive database of MODIS and MERIS images could be used to quantitatively monitor chl-a in the Pearl River estuary.

  3. Decomposition and heavy metal variations of the typical halophyte litters in coastal marshes of the Yellow River estuary, China.

    Science.gov (United States)

    Sun, Zhigao; Mou, Xiaojie; Sun, Wanlong

    2016-03-01

    The concentrations of C, Pb, Cr, Cu, Zn, Ni and Mn were determined in decomposing litters of Phragmites australis, Suaeda salsa and Suaeda glauca in three plots of the Yellow River estuary to investigate the variations of metal stocks. Results showed that the decomposition rates significantly differed among species (p  S. salsa (0.000814 d(-1)) > P. australis (0.000766 d(-1)). The concentrations of Cu and Zn in the three litters (particularly S. glauca) generally showed increasing tendency, while those of Pb, Cr, Ni and Mn exhibited different temporal variations. Compared to P. australis and S. salsa, the key mechanisms affecting the variation of metals in S. glauca might be more complex. In most periods, Pb stocks in P. australis, S. salsa and S. glauca, Zn stocks in S. salsa and S. glauca, and Cr, Ni and Mn stocks in P. australis and S. glauca were lower than the initial ones, implying that release exceeded incorporation. Comparatively, Zn stocks in P. australis, Cr, Ni and Mn stocks in S. salsa and in particular Cu stocks in the three litters were generally positive, evidencing incorporation of these metals in most sampling times. The three halophytes were particular efficient in binding Cu and releasing Pb, indicating that the potential eco-toxic risk of Pb exposure might be serious. This study emphasized the strong influences of key biotic (litter types, carbon/metal ratios and activities of microbial organisms) and abiotic variables (salinity, sediment resuspension induced by tidal inundation and passive sorption onto recalcitrant organic fractions) on metal cycling in coastal marshes of the Yellow River estuary. PMID:26766352

  4. Heavy metal spatial variation, bioaccumulation, and risk assessment of Zostera japonica habitat in the Yellow River Estuary, China.

    Science.gov (United States)

    Lin, Haiying; Sun, Tao; Xue, Sufeng; Jiang, Xiangli

    2016-01-15

    Globally, seagrass habitats are decreasing due to both natural and environmental contaminations by human activities, including heavy metal pollution. To expand the global seagrass detection network, this study reports the spatial distributions of Zostera japonica seagrass habitats in the Yellow River Estuary, China. In addition, heavy metal concentrations of Z. japonica tissue, sediment, and surface seawater were analyzed to determine the bioaccumulation and consequent ecological risk to Z. japonica habitats due to the effects of heavy metals. It was found that concentrations of heavy metals were 1.00-2.03 times higher in seagrass-rooted sediment than in adjacent non-seagrass sediment, except for Mn (with a factor of 0.99). Pb and Hg concentrations in sediments exceeded background values more than the other heavy metals, by factors of 1.74 and 1.24, respectively. Metal concentrations in the surrounding seawater were 2.60-4.63 times higher at seagrass sites than at non-seagrass sites, except for Hg (factor of 0.97). Metal concentrations were much higher in seagrass tissues than in the sediment (e.g., bioconcentration factor of Cd is 30.95). Pb concentrations in water may cause the greatest adverse reactions among aquatic organisms, while As, Cr, Hg, Mn and Cu in sediments may occasionally cause negative ecological effects. Z. japonica showed higher bioaccumulation of Cd and Pb in the above-ground tissues. Among other recent studies of seagrasses from other parts of the world, Cd concentrations are similar to the results of the present study, but Pb concentration in present study is higher than in other studies. In conclusion, Pb and As in the surrounding environment present potential risks to the seagrass habitats of the Yellow River Estuary, China. PMID:26410718

  5. Multi-way analysis for decadal pollution trends assessment: the Guadalquivir River estuary as a case study.

    Science.gov (United States)

    López-López, José A; Mendiguchía, Carolina; García-Vargas, Manuel; Moreno, Carlos

    2014-09-01

    Alongside history, human activities have contributed to the deployment of environmental quality. In particular, during the last decades the problem of water preservation has gained increasing attention. Statistical analysis is essential to analyze environmental data and to identify trends of pollutants over space and time. Usually applied techniques for data treatment are based on the organization of data in a two-way array, missing some shades on pollutants distribution. This fact supports the use of multi-way techniques, which allow the analysis of the results through different directions at the same time. For Three Modes Principal Components Analysis (3MPCA) a principal components analysis is conducted using three modes and a "core" matrix that allows assessing their interactions. In the case of environmental studies, it offers information about the spatial-temporal evolution of pollutants in a certain water body. The Guadalquivir River estuary has been used as a model system. It is a representative human influenced system, where different pollution inputs have been characterized. In this study, decadal evolution of pollutants has been discussed, to evaluate among others the effects of EU legislation on river water quality. The aim of this work is the establishment of the evolution, during the last decade, of nutrients and metals ultra-traces distribution in an estuary affected by anthropic activities. As examples, Pb and PO4(3-) show a trend to decrease their weight on water pollution, total suspended solids (TSS) behavior is related with massive rain events, and the rising of new technologies appears as a source of emerging pollutants as Co in urban-industrial areas. PMID:24997899

  6. 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 Shenzhen. The long-term simulations show depositional trends for the inner bay and the coastline of the outer bay, which could be further aggravated by the detected trends of the driving forces.

  7. Fate of mercury species in the coastal plume of the Adour River estuary (Bay of Biscay, SW France)

    International Nuclear Information System (INIS)

    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−1) while MeHg was efficiently demethylated via both biotic and abiotic pathways (2.3–55.3% day−1), mainly photo-induced. Hg reduction was also effective in these waters (0.3–43.5% day−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−1, in the same range than the estimated MeHg inputs from the estuary (respectively, 0.9 and 3.5 g (Hg) d−1). The large evasion of DGM from the plume waters to the atmosphere (8.8–26.9 g (Hg) d−1) may also limit HgT inputs to coastal waters (33–69 g (Hg) d−1). These processes are thus considered to be most significant in controlling the fate of Hg transferred from the river to the coastal zone. - Highlights: • Reactivity of mercury species was investigated in plume waters of the Adour Estuary. • In situ water incubations were performed to examine transformation processes of Hg. • A net MeHg demethylation was observed via both light induced and biotic pathways. • The estuarine plume exhibits significant loss of MeHg and atmospheric evasion of Hg

  8. [Contribution of different processes in wetland soil N2O production in different restoration phases of the Yellow River estuary, China].

    Science.gov (United States)

    Sun, Wen-Guang; Sun, Zhi-Gao; Gan, Zhuo-Ting; Sun, Wan-Long; Wang, Wei

    2014-08-01

    By using the method of time-space mutual substitution, the contribution of different processes in wetland soil N2O production was studied in the un-restoration wetland (R0), restoration wetland since 2007 (R2007) and restoration wetland since 2002 (R2002) of the Yellow River estuary to evaluate the effectiveness of the restoration projects. Results showed wetland soil total N2O production had a significant difference in different restoration phases, but the N2O release was the main source. The N2O production in restoration wetland was higher than that in un-restoration wetland. The N2O production wss mainly due to the nitrification and nitrifier denitrification processes, while the denitrification process had great weakening effects on N2O production, which was closely related to the physical and chemical properties of wetland soils in different restoration phases. The non-biological processes made greater contributions to N2O production and these were mainly due to that iron was reductive, while the Yellow River estuary was an area of highly active iron. Although N2O production in wetland soils was the results of biological processes combined with non-biological processes in different restoration phases, non-biological processes had larger influences and should be paid a special attention. There were different influences on wetland soil processes generating N2O between temperature and water content, indicating responses of soil microbial activities to temperature and water content were different. In addition, the N2O production contents ranged from 0.37 +/- 0.08 nmol x (kg x h) (-1) to 9.75 +/- 7.64 nmol x (kg x h) (-1) in marshes of the Yellow River estuary, which was slightly higher than those in the S. alterniflora wetland soils of the Min River estuary, but significantly lower than those in the C. malaccensis wetland soils of the Min River estuary, the grassland soils and the aerobic forest soils. We found that the long-term implements of ecological restoration project in the Yellow River estuary obviously promoted N2O production, so we should consider two factors of landscape restoration and weakening greenhouse gases in the next wetland restoration project. PMID:25338387

  9. Preliminary results on the influence of river discharges on biogeochemical processes in Godavari estuary and Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    DileepKumar, M.

    Preliminary results obtained form pilot experiments in Godavari estuary, Andhra Pradesh, India to understand the ecosystem and biogeochemical processes have been presented. During the southwest monsoon the estuary can be, even when the discharge...

  10. Spatio-temporal variability of phytoplankton assemblages in the Pearl River estuary, with special reference to the influence of turbidity and temperature

    Science.gov (United States)

    Shen, Ping-Ping; Li, Gang; Huang, Liang-Min; Zhang, Jian-Lin; Tan, Ye-Hui

    2011-10-01

    The Pearl River Estuary is among the largest estuaries in the subtropical areas of the world. Along the salinity and turbidity gradient between the freshwater reach of the Pearl River and the marine water of the South China Sea, the spatial and temporal composition and abundance of phytoplankton was examined in relation to physic-chemical variables during the dry and wet seasons of 2009. Water samples for phytoplankton and environmental parameters were collected from 18 stations during two seasons along a transect from upper estuary to estuarine and marine sectors. A total of 162 species belonging to 7 phyla were identified, with diatoms dominated in both seasons while dinoflagellates proliferated in autumn. Two main clusters and three sub-clades under each main cluster corresponding to seasons and water sectors were defined with multivariate analysis (cluster and nMDS). Based on the species composition and abundance of phytoplankton, both seasonal and spatial variability were observed at a significant level (ANOSIM: season effect, R=0.896, Pregulating the phytoplankton community structure within the hydrologically distinct zone of estuaries.

  11. Temporal trends of hydrocarbons in sediment cores from the Pearl River Estuary and the northern South China Sea

    International Nuclear Information System (INIS)

    Concentrations and fluxes of unresolved complex mixture of hydrocarbons (UCM) and polycyclic aromatic hydrocarbons (PAHs) were analyzed for two 210Pb dated sediment cores from the Pearl River Estuary (PRE) and the adjacent northern South China Sea (NSCS). Compound-specific stable carbon isotopic compositions of individual n-alkanes were also measured for identification of the hydrocarbon sources. The historical records of PAHs in the NSCS reflected the economic development in the Pearl River Delta during the 20th century. PAHs in the NSCS predominantly derive from combustion of coal and biomass, whereas PAHs in the PRE are a mixture of petrogenic and pyrogenic in origins. The isotopic profiles reveal that the petrogenic hydrocarbons in the PRE originate predominantly from local spillage/leakage of lube oil and crude oils. The accumulation rates of pyrogenic PAHs have significantly increased, whereas UCM accumulation has slightly declined in the NSCS in the recent three decades. - The accumulation rates of pyrogenic PAHs have significantly increased in the northern South China Sea in the recent decades

  12. Initial dilution zone impact assessment of selected industries in the Fraser River estuary. Technical report series No. 93-06

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-12-31

    The initial dilution zone (IDZ) monitoring program is a study to document impacts of wastewater discharges on the receiving environment of the Lower Fraser River in the immediate vicinity of the selected effluent discharges. The IDZ study formed part of the first year of the Fraser River Estuary Monitoring Program environmental monitoring program. The study sampled receiving water and sediments within the IDZs of 10 companies that were also sampled as part of FREMP`s effluent characterization study. A reference site was established near the FREMP water quality monitoring station at Mission. Field measurements included pH, temperature, dissolved oxygen, and salinity. Sediment samples were analyzed for physico-chemical parameters and toxicity. All samples were analyzed for particle size, total organic carbon, and total metals. Sediments from sites related to the forest industry were analyzed for chlorophenols, while polycyclic aromatic hydrocarbons (PAHs) were measured in samples from two companies. Effluent dilutions at the edge of the IDZ were calculated based on the drogue data.

  13. [Phytoplankton assemblages in Yangtze River Estuary in the first sluice discharge duration of Three Gorges Dam in late spring].

    Science.gov (United States)

    Sun, Jun; Zhao, Ran; Zhang, Li-yong

    2011-04-01

    In June 15-25, 2003, the first sluice discharge duration of the Three Gorges Dam, water samples were taken from a grid of survey stations around the Yangtze River Estuary and its adjacent waters to analyze the characteristics of phytoplankton assemblages. In the survey area, the major phytoplankton groups were diatoms and dinoflagellates, and a few species belonging to Chrysophyceae and Chlorophyceae were observed. The cell abundance of the assemblages ranged from 0.2 to 1504.2 cells ml(-1), with an average of 72.7 cells ml(-1), and the dominant species were Skeletonema spp., Prorocentrum dentatum, and Scrippsiella trochoidea. The highest cell abundance was appeared in north diluted waters and southwest inshore waters. The cell abundance was the maximum in mid (10 m) water layer, and the minimum in bottom layer. In diluted waters, Skeletonema spp. was the dominant species, and mainly presented in surface water layer; while in the waters with the diluted water of Yangtze River and the mixed water of Taiwan Warmer Current and Yellow Sea, Prorocentrum dentatum dominated, and mainly distributed in surface and mid water layers. PMID:21774331

  14. 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 $\\delta^{13}$C 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.

  15. Fate and source distribution of organic constituents in a river-dominated tropical estuary

    Science.gov (United States)

    Salas, P. M.; Sujatha, C. H.; Ratheesh Kumar, C. S.

    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) 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.

  16. 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 a function of salinity (salting-out effect). ? Salting constants of PFAAs were notably greater than those of other organic contaminants. ? Results of this study will provide better understanding of PFAAs fate in the field.

  17. In situ fate and partitioning of waterborne perfluoroalkyl acids (PFAAs) in the Youngsan and Nakdong River Estuaries of South Korea

    International Nuclear Information System (INIS)

    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 (Kd) for long-chain PFAAs (C ? 8) were significantly correlated with salinity (r2 = 0.48 to 0.73, p 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 Kd 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 Kd for longer-chain PFAAs (C ? 8) increased as a function of salinity (salting-out effect). ? Salting constants of PFAAs were notably greater than those of other organic contaminants. ? Results of this study will provide better understanding of PFAAs fate in the field

  18. In situ fate and partitioning of waterborne perfluoroalkyl acids (PFAAs) in the Youngsan and Nakdong River Estuaries of South Korea.

    Science.gov (United States)

    Hong, Seongjin; Khim, Jong Seong; Park, Jinsoon; Kim, Minhee; Kim, Woong-Ki; Jung, Jinho; Hyun, Seunghun; Kim, Jeong-Gyu; Lee, Hyojin; Choi, Heeseon J; Codling, Garry; Giesy, John P

    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(d)) for long-chain PFAAs (C?8) were significantly correlated with salinity (r(2)=0.48 to 0.73, p<0.01); K(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(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. PMID:23333509

  19. Metagenomic evidence for reciprocal particle exchange between the mainstem estuary and lateral bay sediments of the lower Columbia River

    Science.gov (United States)

    Smith, Maria W.; Davis, Richard E.; Youngblut, Nicholas D.; Kärnä, Tuomas; Herfort, Lydie; Whitaker, Rachel J.; Metcalf, William W.; Tebo, Bradley M.; Baptista, António M.; Simon, Holly M.

    2015-01-01

    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 ?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. PMID:26483785

  20. 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.

  1. Composition of shrimp populations (Crustacea: Decapoda) in non-vegetated areas of two river islands in a Brazilian Amazon estuary

    Scientific Electronic Library Online (English)

    Priscila Sousa Vilela da, Nóbrega; Bianca, Bentes; Jussara Moretto, Martinelli-Lemos.

    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.

  2. 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. PMID:25604562

  3. 234Th and 7Be as tracers for transport and sources of particle-associated contaminants in the Hudson River Estuary.

    Science.gov (United States)

    Feng, H; Cochran, J K; Hirschberg, D J

    1999-09-30

    The natural radionuclides 234Th and 7Be have known sources in estuaries and strongly and rapidly associate with particles. They are thus good tracers of the transport and sources of particles in the suspended sediment reservoir, and, by implication, of particle-associated contaminants such as heavy metals. In the Hudson River estuary, 234Th is produced from decay of dissolved 238U, which varies linearly with salinity, while 7Be is added directly to the estuary from the atmosphere. The 234Th/7Be activity ratio eliminates variations in radionuclide specific activities that result from changes in sediment grain size or composition. Sampling in the Hudson under conditions of low and high river flow shows that 234Th/7Be in suspended sediment increases from low salinity to higher salinity waters at all sampling times. The Th/Be activity ratio may thus be used as a tracer of where particles are labeled with these radionuclides in the estuary and of the relative importance of resuspension and particle transport through the estuary. The distribution of heavy metals in the suspended sediment reservoir can be compared with that of 234Th/7Be by normalizing the metals to Fe. Iron and Al are well correlated in suspended sediments of the Hudson, indicating that either element can be used to normalize grain size effects on specific concentrations of metals. Ratios of Ag and Pb to Fe in suspended particles generally increase down-estuary at all sampling times, whereas Cu, Zn and Cd-to-Fe ratios show more scatter and less consistency in trends. Both source(s) and chemical behavior affect the metal/Fe ratios. The strongest positive correlation with 234Th/7Be is seen for Ag/Fe, reflecting the dominance of lower estuary sources of this trace metal to the Hudson. Relationships between Pb/Fe, Cu/Fe and 234Th/7Be are less strong, reflecting multiple sources of these elements. No correlation is seen for Cd/Fe with 234Th/7Be, indicating either a source up-river or release of Cd as its Kd decreases with increasing salinity. PMID:10568291

  4. 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.

  5. GAS CHROMATOGRAPHY-FLAME IONIZATION DETECTION FINGERPRINT OF HYDROCARBON EXTRACTS FROM WATER AND SEDIMENTS OF THE GREAT KWA RIVER ESTUARY, SOUTH EASTERN COAST OF NIGERIA

    OpenAIRE

    O.R. OGRI; S.P. MALU; S.T. Ubwa

    2011-01-01

    Various fractions of hydrocarbon in water and sediments from Great Kwa River Estuary (GKRE) Southeast coast of Nigeria were studied quarterly for a period of one year by extracting the total hydrocarbons (THC) from samples. After pre-treatment, finger prints of various hydrocarbon fractions were determined by (GC-FID). Results analysis show that the sediments contain high level of hydrocarbon of crude petroleum origin, suggesting possible impact of petroleum industries in the area. Only 50% o...

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

    OpenAIRE

    James P. Udoh; Anthony A. Nlewadim

    2011-01-01

    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, ?2 = 26.26, 1 df, p < 0.05) and rainy season (1:1.2; ?2 =2.17, I df, p

  7. Challenges and opportunities for the business sector in the fight against poverty : the case of Brazil’s Amazon River estuary

    OpenAIRE

    Barney Gonzalez, M.J.; Meirelles, J.

    2008-01-01

    This paper explores the actions and strategies of three companies, and the dilemmas and bottlenecks they faced in their attempts to contribute to sustainability and poverty alleviation through business operations in the Amazon River Estuary. The results of the paper are based on three case studies carried out by the Royal Tropical Institute (KIT) using a quick-scan approach, as part of KIT’s research into corporate social responsibility from the perspective of social and gender equity.

  8. Wetland ecosystems for denitrification processes in rivers: A comparison for implementation in the lower Seine River and its estuary (France)

    OpenAIRE

    Deconinck, Nico

    2011-01-01

    ABSTRACT Wetlands are generally recognized for their denitrification and nitrate removal capacities, but their performance can vary seriously. Moreover, a general agreement about the definition of the several kinds of wetlands is still lacking. In this study 5 ways for categorizing wetlands and subdividing them in several types and subtypes. Next, a selection of 5 rivers with wetlands in the United States and 3 in Europe was made. As result, these rivers were associated with connected and...

  9. Seasonal effects of wastewater to the water quality of the Caeté river estuary, Brazilian Amazon

    Scientific Electronic Library Online (English)

    Luci C.C., Pereira; Marcela C., Monteiro; Danielly O., Guimarães; Jislene B., Matos; Rauquírio M. da, Costa.

    2010-06-01

    Full Text Available A situação socioeconômica de Bragança depende principalmente dos recursos biológicos estuarinos e marinhos, que são influenciados pelos ciclos de marés e climatologia. Coletas oceanográficas (com medidas de variáveis hidrológicas, hidro-dinâmicas e microbiológicas) foram realizadas na área mais urba [...] nizada do estuário do Caeté, para caracterizar a qualidade das águas no setor estudado. Durante o período seco, o estuário foi mais eutrófico e apresentou os maiores valores de temperatura (30,5°C em Out./06), salinidade (17 psu em Fev./07), pH (8,24 em Fev./07) e coliformes fecais (>1000 MNP/ 100 ml em Dez./06 e Fev./07). As espécies fitoplanctô-nicas Cyclotella meneghiniana, Coscinodiscus centralis e outras espécies r-estrategistas também foram observadas. A falta de saneamento básico foi responsável pela contaminação local, especialmente durante o período seco, quando o esgoto foi lançado mais concentrado no estuário, mostrando a influência humana na redução da qualidade da água estuarina estudada. A pesca é considerada uma das principais atividades econômicas do município de Bragança e, portanto, esta contaminação poderá afetar negativamente a qualidade ambiental deste ecossistema amazônico. Abstract in english Bragança's socioeconomic situation is highly dependent on estuarine and marine biological resources that are influenced by tidal cycles and climatology. Field measurements (hydrological, hydrodynamic and microbiological variables) were taken in the most urbanized zone from Caeté estuary to character [...] ise the quality of the local environment. During the dry period, the estuary was more eutrophic and presented the highest temperature (30.5 °C in Oct./06), salinity (17 psu in Feb./07), pH (8.24 in Feb./07) and fecal coliform (> 1000 MPN/100 ml in Dec./06 and Feb./07) values. The phytoplankton Cyclotella meneghiniana, Coscinodiscus centralis and other r-strategist species were observed. The lack of basic hydric canalization was responsible for the local contamination, especially during the dry period when more concentrated wastewater from the city was emitted into the estuary, showing the human influence on the reduction of local estuarine water quality. In Bragança, the fishery is considered one of the main economic activities so, this contamination is worrisome because a large part of the local economy depends on biological resources and, thus, the contamination could negatively affect the environmental health of this Amazon ecosystem.

  10. Seasonal effects of wastewater to the water quality of the Caeté river estuary, Brazilian Amazon

    Directory of Open Access Journals (Sweden)

    Luci C.C. Pereira

    2010-06-01

    Full Text Available Bragança's socioeconomic situation is highly dependent on estuarine and marine biological resources that are influenced by tidal cycles and climatology. Field measurements (hydrological, hydrodynamic and microbiological variables were taken in the most urbanized zone from Caeté estuary to characterise the quality of the local environment. During the dry period, the estuary was more eutrophic and presented the highest temperature (30.5 °C in Oct./06, salinity (17 psu in Feb./07, pH (8.24 in Feb./07 and fecal coliform (> 1000 MPN/100 ml in Dec./06 and Feb./07 values. The phytoplankton Cyclotella meneghiniana, Coscinodiscus centralis and other r-strategist species were observed. The lack of basic hydric canalization was responsible for the local contamination, especially during the dry period when more concentrated wastewater from the city was emitted into the estuary, showing the human influence on the reduction of local estuarine water quality. In Bragança, the fishery is considered one of the main economic activities so, this contamination is worrisome because a large part of the local economy depends on biological resources and, thus, the contamination could negatively affect the environmental health of this Amazon ecosystem.A situação socioeconômica de Bragança depende principalmente dos recursos biológicos estuarinos e marinhos, que são influenciados pelos ciclos de marés e climatologia. Coletas oceanográficas (com medidas de variáveis hidrológicas, hidro-dinâmicas e microbiológicas foram realizadas na área mais urbanizada do estuário do Caeté, para caracterizar a qualidade das águas no setor estudado. Durante o período seco, o estuário foi mais eutrófico e apresentou os maiores valores de temperatura (30,5°C em Out./06, salinidade (17 psu em Fev./07, pH (8,24 em Fev./07 e coliformes fecais (>1000 MNP/ 100 ml em Dez./06 e Fev./07. As espécies fitoplanctô-nicas Cyclotella meneghiniana, Coscinodiscus centralis e outras espécies r-estrategistas também foram observadas. A falta de saneamento básico foi responsável pela contaminação local, especialmente durante o período seco, quando o esgoto foi lançado mais concentrado no estuário, mostrando a influência humana na redução da qualidade da água estuarina estudada. A pesca é considerada uma das principais atividades econômicas do município de Bragança e, portanto, esta contaminação poderá afetar negativamente a qualidade ambiental deste ecossistema amazônico.

  11. 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 analysis. Salinity, low dissolved oxygen saturation and sediment properties accounted for further community splits in the estuarine Murray Mouth. This long term monitoring revealed ecological benefits of intermediate and continuous flow and that resilience of estuarine macrobenthos to drought and flood events was affected by flow history. The index can be applied to other flow regulated estuaries and inform environmental watering targets.

  12. Impacts of human activities on nutrient transports in the Huanghe (Yellow River) estuary

    Science.gov (United States)

    Liu, Su Mei; Li, Ling Wei; Zhang, Gui Ling; Liu, Zhe; Yu, Zhigang; Ren, Jing Ling

    2012-04-01

    SummaryThe impacts of anthropogenic activities on nutrient transport in the Huanghe/estuary were investigated using biogeochemical observations carried out during 2008-2009 to examine how nutrient change during a water-sediment regulation event. Nutrient concentrations in the Huanghe are characterized by relative high concentrations of nitrate and dissolved silicate but low phosphate and DOP levels and shows seasonal variations with very high DIN/PO43- ratios. The water-sediment regulation event resulted in high monthly average water discharge and sediment load occurring at least 2 months prior to before the event. The nutrient transport fluxes increased 8-30 times during that period. The regulation event has shifted the seasonal patterns of water and nutrient transport, which cannot only increase nutrient inputs to the coastal ecosystem but can also result in nutrient imbalance, affecting phytoplankton production and composition.

  13. The distribution and occurrence of the marine manatee (Trichechus manatus in the estuary of the Mamanguape River, Paraíba, Brazil

    Directory of Open Access Journals (Sweden)

    Kleber Grubel da Silva

    2011-12-01

    Full Text Available Although the existing historical records of marine manatees in the Brazilian coast since the 17th century, few studies about this species were conducted in Brazil. Among them, the estuary of the Mamanguape River is told to be the main place of this species concentration in the northeastern coast of Brazil, but this one is suffering oppression due to the improvement of human activities which can compromise the ecosystem as a whole. In this way, this work viewed to obtain information about the marine manatee´s ecology and behavior in the estuary of the Mamanguape River, establishing seasonal modifications in its emergence, checking preferable places of occupation and detecting possible human activities which interfere in its biological cycle. With this purpose, it was developed one program for marine manatee groups in the region of Bar of Mamanguape and adjacent, by direct observation and interviews with fishers from 1988 to 1991. During the studies period, 608 monitoring visits were made to Bar of Mamanguape, totalizing 285 watching of isolated or grouped manatees and 2.185 hours of observation in fixed places. The major number of sightings happened from October to May, when the animals were seen more regularly and frequently in groups. From June to September, the animals went to that region sporadically and almost always alone. The biggest group observed was one formed by nine animals and the biggest one of registered animals at the same time was by 11 manatees. It was detected that the human activities which produce many noises in the water interfere with the animals´ behavior, scaring and dispersing the groups. Purse seines, drift and gill nets, used in the region, when closer to the groups, besides scaring away the animals, can be damaged due to the possible collisions with the marine manatees. Already the more resistant gill nets (caçoás imply extreme danger, because can flog the animals and get them to death. It is concluded that the region of the Bar of Mamanguape is of paramount importance for the maintenance of the reproductive cycle of the marine manatee, because it is one of their most concentration in the Northeast of Brazil. Creating restrictive zones within the Area of Environmental Preservation (AEP of the Bar of Mamanguape and ranking human activities are essential for the preservation of this species.

  14. Concentrations and fluxes of dissolved uranium in the Yellow River estuary: seasonal variation and anthropogenic (Water-Sediment Regulation Scheme) impact

    International Nuclear Information System (INIS)

    The Water-Sediment Regulation Scheme (WSRS) of the Yellow River is a procedure implemented annually from June to July to expel sediments deposited in Xiaolangdi and other large middle-reach reservoirs and to scour the lower reaches of the river, by controlling water and sediment discharges. Dissolved uranium isotopes were measured in river waters collected monthly as well as daily during the 2010 WSRS (June 19–July 16) from Station Lijin (a hydrologic station nearest to the Yellow River estuary). The monthly samples showed dissolved uranium concentrations of 3.85–7.57 ?g l?1 and 234U/238U activity ratios of 1.24–1.53. The concentrations were much higher than those reported for other global major rivers, and showed seasonal variability. Laboratory simulation experiments showed significant uranium release from bottom and suspended sediment. The uranium concentrations and activity ratios differed during the two stages of the WSRS, which may reflect desorption/dissolution of uranium from suspended river sediments of different origins. An annual flux of dissolved uranium of 1.04 × 108 g y?1 was estimated based on the monthly average water discharge and dissolved uranium concentration in the lower reaches of the Yellow River. The amount of dissolved uranium (2.65 × 107 g) transported from the Yellow River to the sea during the WSRS constituted about 1/4 of the annual flux. -- Highlights: • Dissolved U in the Yellow River estuary has distinct seasonal variability. • Geochemistry of dissolved U influenced by the WSRS has been analyzed. • Uranium flux during the WSRS has been evaluated

  15. 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 coastal zone. - Highlights: • Reactivity of mercury species was investigated in plume waters of the Adour Estuary. • In situ water incubations were performed to examine transformation processes of Hg. • A net MeHg demethylation was observed via both light induced and biotic pathways. • The estuarine plume exhibits significant loss of MeHg and atmospheric evasion of Hg.

  16. Sources and Transformations of Carbon and Nitrogen in the Potomac River Estuary

    Science.gov (United States)

    Pennino, M. J.; Kaushal, S.; Murthy, S.

    2011-12-01

    Urbanization has altered the transport of nitrogen (N) and carbon (C) in river ecosystems, making it important to understand how rivers are responding to these increased inputs of C and N. This study examines the capacity of a major tributary of the Chesapeake Bay, the Potomac River, to transform N and C inputs from the world's largest advanced wastewater treatment facility (Washington D.C. Water and Sewer Authority). Surface water and effluent samples were collected monthly for one year, along longitudinal transects of the Potomac River. Water samples were analyzed for the major dissolved and particulate forms of C and N. Nitrate stable isotopes were used to trace the fate of wastewater nitrate, as well as how other nitrate sources vary downriver. Sources of carbon downriver were traced using fluorescence spectroscopy, excitation emission matrices (EEMs), and PARAFAC modeling. Historical influent and effluent data on C and N levels were also compared with regional population growth data, climate change data, and long-term interannual records of C and N levels within downstream stations along the Potomac River. Improvements in treatment technology over the past two decades have shown significant decreases in effluent nitrogen levels, with corresponding decreases overtime of nutrients at downstream sampling stations. Levels of nitrate show increases within the vicinity of the wastewater treatment outfall, but decrease rapidly downstream, potentially indicating nutrient uptake and/or denitrification. Total organic carbon levels show a smaller decrease downstream, resulting in an increase in the C:N ratio downstream. Longitudinal river chemistry data also show that dissolved inorganic nitrogen goes down while total organic nitrogen goes up with distance downriver, indicating biological transformations are taking place along the river. Preliminary data from fluorescence EEMs suggested that more humic-like organic matter is important above the wastewater treatment plant, but more protein-like organic matter is present below the treatment plant. However, this fluorescence signal from wastewater organic matter disappears within 2-4 km downriver, indicating rapid processing of the labile organic matter within the river. Nitrate isotope data for both upriver and downriver samples show a signal from manure or sewage inputs, indicating a potential influence from animal farms upstream in the Potomac. However, only the downriver samples show evidence for denitrification. Additionally, the higher 15N isotope levels of nitrate, which are characteristic of wastewater sources, disappear by 20 km downriver. Majors rivers like the Potomac may have a huge capacity for transforming and processing large carbon and nitrogen inputs within a short distance. Greater knowledge of how land management and climate change impacts these transformations will be important in predicting changes in the amounts, forms, and stoichiometry of nutrient loads to coastal waters.

  17. Development of a Hydrodynamic Model for Skagit River Estuary for Estuarine Restoration Feasibility Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Zhaoqing; Liu, Hedong; Khangaonkar, Tarang P.

    2006-08-03

    The Skagit River is the largest river in the Puget Sound estuarine system. It discharges about 39% of total sediment and more than 20% of freshwater into Puget Sound. The Skagit River delta provides rich estuarine and freshwater habitats for salmon and many other wildlife species. Over the past 150 years, economic development in the Skagit River delta has resulted in significant losses of wildlife habitat, particularly due to construction of dikes. Diked portion of the delta is known as Fir Island where irrigation practices for agriculture land over the last century has resulted in land subsidence. This has also caused reduced efficiency of drainage network and impeded fish passages through the area. In this study, a three-dimensional tidal circulation model was developed for the Skagit River delta to assist estuarine restoration in the Fir Island area. The hydrodynamic model used in the study is the Finite Volume Coastal Ocean Model (FVCOM). The hydrodynamic model was calibrated using field data collected from the study area specifically for the model development. Wetting and drying processes in the estuarine delta are simulated in the hydrodynamic model. The calibrated model was applied to simulate different restoration alternatives and provide guidance for estuarine restoration and management. Specifically, the model was used to help select and design configurations that would improve the supply of sediment and freshwater to the mudflats and tidal marsh areas outside of diked regions and then improve the estuarine habitats for salmon migration.

  18. Development of a Hydrodynamic Model for Skagit River Estuary for Estuarine Restoration Feasibility Assessment

    International Nuclear Information System (INIS)

    The Skagit River is the largest river in the Puget Sound estuarine system. It discharges about 39% of total sediment and more than 20% of freshwater into Puget Sound. The Skagit River delta provides rich estuarine and freshwater habitats for salmon and many other wildlife species. Over the past 150 years, economic development in the Skagit River delta has resulted in significant losses of wildlife habitat, particularly due to construction of dikes. Diked portion of the delta is known as Fir Island where irrigation practices for agriculture land over the last century has resulted in land subsidence. This has also caused reduced efficiency of drainage network and impeded fish passages through the area. In this study, a three-dimensional tidal circulation model was developed for the Skagit River delta to assist estuarine restoration in the Fir Island area. The hydrodynamic model used in the study is the Finite Volume Coastal Ocean Model (FVCOM). The hydrodynamic model was calibrated using field data collected from the study area specifically for the model development. Wetting and drying processes in the estuarine delta are simulated in the hydrodynamic model. The calibrated model was applied to simulate different restoration alternatives and provide guidance for estuarine restoration and management. Specifically, the model was used to help select and design configurations that would improve the supply of sediment and freshwater to the mudflats and tidal marsh areas outside of diked regions and then improve the estuarine habitats for salmon migration

  19. 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.

  20. 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 calculated from both CLPP and DGGE data ( H>3.2) was higher than that of others as sewage discharge may increase water nitrogen and phosphorus nutrient. The bacterial community structure of S6, S8, S11 and S12 was greatly influenced by total phosphorous, salinity and total nitrogen. Based on DGGE fingerprinting, proteobacteria, especially ?- and ?-proteobacteria, were found dominant at all sites. In conclusion, the aquaculture area and wharf had high microbial metabolic capability. The structure and composition of bacterial community were closely related to the level of phosphorus, salinity and nitrogen.

  1. Biogeochemistry of bulk organic matter and biogenic elements in surface sediments of the Yangtze River Estuary and adjacent sea.

    Science.gov (United States)

    Yang, Bin; Cao, Lu; Liu, Su-Mei; Zhang, Guo-Sen

    2015-07-15

    This study investigated the distribution and roles of total organic carbon (TOC), biogenic silicon (BSi), various forms of nitrogen (N) and phosphorus (P), and the stable carbon isotope (?(13)C) in surface sediments of the Yangtze River Estuary (YRE) and adjacent sea. Terrestrial input accounted for 12-63% of total organic matter in the study area. The distribution of biogenic elements was affected by the Changjiang Diluted Water, the Jiangsu Coastal Current, human activities, marine biological processes, and the sediment grain size. Potentially bioavailable N and P accounted for an average 79.6% of the total N (TN) and 31.8% of the total P (TP), respectively. The burial fluxes for TOC, BSi, TN and TP were 39.74-2194.32, 17.34-517.48, 5.02-188.85 and 3.10-62.72 ?mol cm(-2) yr(-1), respectively. The molar ratios of total N/P (1.2-5.0), Si/P (5.0-14.8) and Fe/P (21-61) indicated that much of the P was sequestered in sediments. PMID:25960273

  2. Non-aromatic hydrocarbons in surface sediments near the Pearl River estuary in the South China Sea

    International Nuclear Information System (INIS)

    Surface sediment samples at 4 sites along an offshore transect from outer continental shelf off the Pearl River estuary to the shelf slope region of the northern South China Sea, have been analyzed for total organic carbon (TOC), total nitrogen (TN), solvent extractable organic matter (EOM) and non-aromatic hydrocarbons. TOC, TN and EOM show distinct spatial variations. Their highest values are all recorded at the shelf slope region. EOM varies from 18.70-38.58 ?g g-1 dry sediment and accounts for 0.20-0.72% of the TOC contents. The non-aromatic hydrocarbons are an important fraction of EOM. Their contents range from 3.43-7.06 ?g g-1 dry sediment. n-Alkanes with carbon number ranging from 15-38 are identified. They derive from both biogenic and petrogenic sources in different proportions. Results of isoprenoid hydrocarbons, hopanes and steranes also suggest possible petroleum contamination. - Anthropogenic activities have influences on the composition of non-aromatic hydrocarbons in the surface sediments of the northern South China Sea outer continental shelf

  3. Responses of summer phytoplankton community to drastic environmental changes in the Changjiang (Yangtze River) estuary during the past 50 years.

    Science.gov (United States)

    Jiang, Zhibing; Liu, Jingjing; Chen, Jianfang; Chen, Quanzhen; Yan, Xiaojun; Xuan, Jiliang; Zeng, Jiangning

    2014-05-01

    The phytoplankton community in the Changjiang Estuary is subject to intensive physical and chemical stresses because of human- and climate-driven changes. We obtained historical data on summer phytoplankton communities from 1959 to 2009 to explore responses to long-term environmental changes. The nitrogen (N) and phosphorus (P) concentrations and ratios (N/P and N/Si) increased because of persistent riverine loading, but silicon (Si) levels remained constant. Climatic changes and extensive water diversions and withdrawals (sediment retention) resulted in a series of physical alterations, including increased temperature, turbidity reduction, and river plume shrinkage. These changes induced a dramatic increase in microalgal biomass (cell density and chlorophyll a) with a decreasing diatom-dinoflagellate ratio, and exacerbated harmful algal blooms. In the past dominant net-collected species were usually chain-forming diatoms; however, more recently, large dinoflagellates and filamentous cyanobacteria dominate. This was not consistent with information from water samples (co-dominated by small dinoflagellates), because of the loss of solitary species collected using a 76-?m net. The dominant species shifted from temperate-subtropical/eurythermal to subtropical-tropical/eurythermal taxa in the warmer water caused by global warming and hydrographic changes. There was also an increased dominance of euryhaline/high-salinity species due to increase in Kuroshio transport and the northward Taiwan Warm Current and reduction in Changjiang Diluted Water. All these changes in phytoplankton communities appear to be closely related to an increase in anthropogenic activities and climatic changes. PMID:24531075

  4. Valuing Ecosystem Services with Fishery Rents: A Lumped-Parameter Approach to Hypoxia in the Neuse River Estuary

    Directory of Open Access Journals (Sweden)

    Larry B. Crowder

    2011-11-01

    Full Text Available Valuing ecosystem services with microeconomic underpinnings presents challenges because these services typically constitute nonmarket values and contribute to human welfare indirectly through a series of ecological pathways that are dynamic, nonlinear, and difficult to quantify and link to appropriate economic spatial and temporal scales. This paper develops and demonstrates a method to value a portion of ecosystem services when a commercial fishery is dependent on the quality of estuarine habitat. Using a lumped-parameter, dynamic open access bioeconomic model that is spatially explicit and includes predator-prey interactions, this paper quantifies part of the value of improved ecosystem function in the Neuse River Estuary when nutrient pollution is reduced. Specifically, it traces the effects of nitrogen loading on the North Carolina commercial blue crab fishery by modeling the response of primary production and the subsequent impact on hypoxia (low dissolved oxygen. Hypoxia, in turn, affects blue crabs and their preferred prey. The discounted present value fishery rent increase from a 30% reduction in nitrogen loadings in the Neuse is $2.56 million, though this welfare estimate is fairly sensitive to some parameter values. Surprisingly, this number is not sensitive to initial conditions.

  5. Geochemistry of carbon stable isotope in Shatt AL-Arab River and Khor AL-Zubair Estuary, South Iraq

    International Nuclear Information System (INIS)

    24 samples of Mollusc shells from Shatt AL-Arab river and Khor AL-Zubair estuary were analyzed in order to determine the concentration of carbon stable isotope and also to clarify the factors that control the geochemical distribution of carbon isotopes in these two different environments. The carbon stable isotope were measured using the dosed tube method, in which shell samples are combusted to carbon dioxide for carbon isotope analysis. The carbon dioxide samples are analyzed on a Finnigan Mat 251 isotope ratio mass spectrometer equipped with a triple collector and controlled by an Apple He microcomputer. Measurements are made relative to several working standards {Norit (-24 per mille),NBS-22 (-29 per mille)}, and several secondary light methane standards at -43.4 per mille and -62.6 per mille. All values are reported versus PDB. These analyses are conducted in the department, of Oceanography in Texas A and M University. This study indicates that the differences in carbon stable isotopes were due to three factors: environmental conditions, under which these three molluscs are lived, chemistry of the water in Shatt AL-Arab and Khor AL-Zubair and feeding quality of these of these molluscs. The factors are close related with another important factor that it. is the pollution present in these two different environments. (author)

  6. 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.

  7. Controlling factors of summer phytoplankton community in the Changjiang (Yangtze River) Estuary and adjacent East China Sea shelf

    Science.gov (United States)

    Jiang, Zhibing; Chen, Jianfang; Zhou, Feng; Shou, Lu; Chen, Quanzhen; Tao, Bangyi; Yan, Xiaojun; Wang, Kui

    2015-06-01

    We analyzed the composition and distribution of phytoplankton in relation to physicochemical factors in the Changjiang (Yangtze River) Estuary and adjacent East China Sea shelf in June and August 2009. Diatoms and dinoflagellates dominated the community, particularly in eutrophic inshore waters controlled by the Changjiang Diluted Water (CDW), coastal current, and upwelling. However, high densities of cyanobacteria and cryptophytes were observed in the oligotrophic offshore waters influenced by the Taiwan Warm Current (TWC) and Kuroshio. In June, the northeastward CDW plume combined with the Yellow Sea Coastal Current induced algal bloom in the northern part of the CE. In August, the enhanced CDW formed two narrow, low-salinity tongues that extended eastward and southward (associated with the upwelling and coastal current), resulting in phytoplankton blooms off the CE and in the Zhejiang coastal waters, respectively. Phytoplankton abundance in August was considerably higher than in June, with increased solar radiation, CDW, and upwelling. The maximum abundance occurred on the surface in inshore turbid waters and on the subsurface (5-30 m) in offshore clear waters with increased stratification. Based on multidimensional scaling and cluster analysis, we found appreciable spatio-temporal variations in algal community composition. Different ecological groups corresponded with hydrographic distributions. Canonical correspondence analysis showed that nutrients, salinity, temperature, and suspended particulate matter were the main variables associated with community distribution. We suggest that the variations in summer phytoplankton community are highly correlated with the significant monthly and spatial variability in physicochemical properties, which are primarily controlled by the CDW and TWC.

  8. Bioaccumulation and biomagnification of halogenated organic pollutants in mangrove biota from the Pearl River Estuary, South China.

    Science.gov (United States)

    Sun, Yu-Xin; Zhang, Zai-Wang; Xu, Xiang-Rong; Hu, Yong-Xia; Luo, Xiao-Jun; Cai, Ming-Gang; Mai, Bi-Xian

    2015-10-15

    Four biota species were collected from mangrove ecosystems of the Pearl River Estuary to investigate the bioaccumulation and biomagnification of polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT), polybrominated diphenyl ethers (PBDEs), dechlorane plus (DP), and decabromodiphenyl ethane (DBDPE). Concentrations of ?PCBs, ?DDTs, ?PBDEs, DP, DBDPE and anti-Cl11-DP (the dechlorination product of anti-DP) in mangrove biota ranged from 32.1-466, 153-3819, 3.88-59.8, 0.18-6.88, not detected (nd)-30.6 and nd-2.65 ng/g lipid weight, respectively. Daggertooth pike conger (Muraenesox cinereus) had higher concentrations of contaminants than the other three biota species. Significant positive relationship between anti-Cl11-DP and anti-DP levels was observed in mangrove biota. DDTs were the predominant HOPs in all biota species, followed by PCBs and PBDEs. All the target compounds exhibited biomagnification, with biomagnification factors greater than 1 in the studied feeding relationships. Food web magnification was found for ?PCBs, ?DDTs, ?PBDEs and DP, with trophic magnification factors of 2.76, 2.61, 2.20 and 2.31, respectively. PMID:26209127

  9. The source of natural and anthropogenic heavy metals in the sediments of the Minjiang River Estuary (SE China): Implications for historical pollution

    International Nuclear Information System (INIS)

    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 206Pb/207Pb and 206Pb/208Pb 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

  10. Cycling of transuranic radionuclides in the Columbia River, its estuary, and the North Pacific Ocean. Progress report, February 1, 1978--February 15, 1979

    International Nuclear Information System (INIS)

    Progress from February 1978 through January 1979 on the measurement of radionuclides in the Columbia River and its estuary, with principal emphasis on plutonium isotopes is reported. The goal is to budget the inventory of transuranic radionuclides in the Columbia River system below the Hanford Complex and to estimate the amounts of Pu and Am being carried to the Northeast Pacific Ocean by the river. The results to date have led to conclusions of some importance to the Department of Energy. These are as follows: (1) previously published data on the concentrations of plutonium in McNary reservoir are incorrect. The reported analyses show Pu concentrations significantly lower than those reported by Battelle; (2) sedimentation rates in McNary reservoir do not appear to be as high as those estimated by previous workers. Using Pu and 137Cs subsurface maxima and 238239240Pu ratios, it is concluded that the sedimentation rates in the lower portion of McNary reservoir near the Oregon shore are between 4 and 5 cm/yr and decrease dramatically as the Washington shore is approached. Sedimentation rates at Ice Harbor Dam on the Snake River and at Bonneville Dam on the Columbia are about 2 cm/yr; (3) in the Columbia River estuary where fine sediments are accumulating at a rate of about 3 to 4 cm/yr, plutonium does not appear to be migrating from depth toward the surface.; (4) evidence suggests that the contribution of the eight plutonium production reactors to the integrated plutonium inventory of Columbia River sediments is small; (5) a surprising fraction of the plutonium in Columbia River water is not retained by 0.3? millipore filters; and (6) in certain regions Columbia River sediments contain rather high mean plutonium loads (mCi/km2). Each of these topics is discussed as well as the results of participation in both national and international quality control and intercalibration exercises

  11. Radium isotopes as a tool for the study of water mixing in the Paraiba do Sul River Estuary

    International Nuclear Information System (INIS)

    Four isotopes of radium with different half-lives exist in nature. In aquatic systems, radium isotopes present distinct characteristics in salt water and fresh water environments. In fresh waters, radium appears adsorbed to particulate material while in sea water radium presents a conservative behavior, being the concentration of different isotopes of radium governed by the processes of dilution, advection and diffusion, as well as radioactive decay. The four natural isotopes of radium are tracers extensively used to determine ratios of water mixture and to calculate the period since the radium was added to the water column. The short-lived isotopes, 223Ra (half-life = 11.4 days) and 224Ra (half-life = 3.66 days), are continually regenerated from decay of their thorium parents, which are perpetually bound to particles surfaces. On the other hand, the long-lived isotopes, 226Ra (half-life = 1600 yrs) and 228Ra (half-life = 5.7 yrs), require considerable time for regeneration. These fluxes must be sustained by input water from rivers, sediments, SGD, or other sources. In the present work, developed at the estuary of the Paraiba do Sul River, the short half-lived radium isotopes (224Ra and 223Ra) were determined using the technique of coincidence delayed developed. The isotopes of long half-lifed (2226Ra and 2228Ra) were determined by the technique of total alpha and beta counting, after the dissolution of the MnO2 fiber used to pre-concentrate radium. (author)

  12. A survey of benthic sediment contaminants in reaches of the Columbia River Estuary based on channel sedimentation characteristics.

    Science.gov (United States)

    Counihan, Timothy D; Waite, Ian R; Nilsen, Elena B; Hardiman, Jill M; Elias, Edwin; Gelfenbaum, Guy; Zaugg, Steven D

    2014-06-15

    While previous studies have documented contaminants in fish, sediments, water, and wildlife, few specifics are known about the spatial distribution of contaminants in the Columbia River Estuary (CRE). Our study goal was to characterize sediment contaminant detections and concentrations in reaches of the CRE that were concurrently being sampled to assess contaminants in water, invertebrates, fish, and osprey (Pandion haliaetus) eggs. Our objectives were to develop a survey design based on sedimentation characteristics and then assess whether sediment grain size, total organic carbon (TOC), and contaminant concentrations and detections varied between areas with different sedimentation characteristics. We used a sediment transport model to predict sedimentation characteristics of three 16km river reaches in the CRE. We then compartmentalized the modeled change in bed mass after a two week simulation to define sampling strata with depositional, stable, or erosional conditions. We collected and analyzed bottom sediments to assess whether substrate composition, organic matter composition, and contaminant concentrations and detections varied among strata within and between the reaches. We observed differences in grain size fractions between strata within and between reaches. We found that the fine sediment fraction was positively correlated with TOC. Contaminant concentrations were statistically different between depositional vs. erosional strata for the industrial compounds, personal care products and polycyclic aromatic hydrocarbons class (Indus-PCP-PAH). We also observed significant differences between strata in the number of detections of Indus-PCP-PAH (depositional vs. erosional; stable vs. erosional) and for the flame retardants, polychlorinated biphenyls, and pesticides class (depositional vs. erosional, depositional vs. stable). When we estimated mean contaminant concentrations by reach, we observed higher contaminant concentrations in the furthest downstream reach with a decreasing trend in the two upstream reaches. Contaminant survey designs that account for sedimentation characteristics could increase the probability that sampling is allocated to areas likely to be contaminated. PMID:24703225

  13. Dynamics of carbon-and oxygen stable isotopes in Paraguacu river estuary-Bahia, Brazil

    International Nuclear Information System (INIS)

    Measurements of ΔC13 and ΔO18 have been made in water samples and carbonate sediments from the Paraguacu estuary with to a precision of X0,1%. Water samples were collected in the complete salinity range from 0% to 35% with the fresh water having the lowest O18/O16 ratios of 4,3%. Alinear correlations exists between salinity and the oxygen isootopic composition suggesting that O18/O16 behaves as a conservative property during the mixing of fresh water with sea water. With respect to the carbonate sediments, there exists a correlation between ΔO18 and ΔC13, indicating the need of ΔC13 measurements when ΔO18is being used as a temperature indicator. Since the carbonate shells are derivedfrom soluble HCO3 the possibility is shown of using ΔO18 as an indicator of the mean salinity at a given locality. (Author)

  14. Variability in salt flux and water circulation in Ota River Estuary, Japan

    Directory of Open Access Journals (Sweden)

    Mohammad SOLTANIASL

    2013-07-01

    Full Text Available In this study the sub-tidal and intra-tidal variations of salt fluxes in the upstream section of a shallow estuary (with a water depth of less than 3 m were investigated. The salt fluxes were estimated based on the cross-sectional average salinity and velocity measured by the fluvial acoustic tomography system (FATS. The results indicate that the magnitude of seaward fluxes is approximately two times greater than that of landward fluxes under normal conditions. The results of short-term observation in the study area indicate that there is a phase lag of the bottom and surface salinities between the regions with the largest and smallest depths. The vertical shear flux with a peak value of ?0.7 m2/s during the ebb tide indicated an important contribution to the total salt flux compared with the advective flux. A phase lag occurred between the vertical shear terms in the regions with the largest and smallest depths, which resulted from the correlation between the vertical variations of the salinity and velocity and the existence of transversal velocity circulations.

  15. Hydrocarbons in surface sediments from the Changjiang (Yangtze River) estuary, East China Sea

    Energy Technology Data Exchange (ETDEWEB)

    Bouloubassi, Ioanna; Fillaux, Joelle; Saliot, Alain [Universite Pierre et Marie Curie, Lab. de Biogeochimie et Chimie Marines, Paris, 75 (France)

    2001-07-01

    Sedimentary aliphatic (AH) and polycyclic aromatic hydrocarbons (PAHs) were studied in the Changjiang Estuary and the adjacent East China Sea. Total AH ranged from 2.20 to 11.82 {mu}g g {sup -1} and consisted of n-alkanes and a dominant petroleum-related unresolved complex mixture (UCM). Within the n-alkanes, terrestrial plant wax compounds prevailed at nearly all stations. Of the PAHs, biogenic perylene dominated at stations receiving riverine inputs. Anthropogenic PAHs originating from combustion/pyrolysis processes varied from 17 to 157 ng g {sup -1}, while fossil PAH concentrations ranged from 42 to 187 ng g {sup -1}. Both biogenic and anthropogenic hydrocarbons are primarily derived from riverine discharges and accumulate at shallow-water stations. Distinct phase associations lead, nevertheless, to different sedimentation patterns. Fossil PAHs are enhanced at offshore stations where they are introduced directly by shipping activities. Biomarker fingerprints ascribe their source to Chinese crude oils. The overall levels of anthropogenic hydrocarbons are low compared to relevant areas worldwide and reveal a low/moderate level of hydrocarbon pollution. (Author)

  16. 6 Structural variation in mangrove forests of the estuary of the River Itabapoana, ES-RJ

    Directory of Open Access Journals (Sweden)

    Elaine Bernini

    2010-03-01

    Full Text Available We analyzed the structure of 13 sites of mangrove vegetation in the Itabapoana estuary by use of the methodology of permanent plots. Considering all individuals >1m within the plots, the average height of forests ranged from 4.0 to 10.1m, the average DBH (diameter at breast height ranged from 3.7 to 13.5cm, the basal area of living individuals was 13.5 to 48.3m2.ha-1, and the density of trunks was 1,475 to 21,000 trunks.ha-1. Overall, there was a greater contribution of the live basal area in relation to diameter >10.0cm (59%. Forests with better structural development exhibited a dominance of Avicennia germinans (L. Stearn, while Laguncularia racemosa (L. Gaertn. f. was dominant in less-developed forests. Our results showed that environmental features and biotic factors contribute to mangrove differentiation among sites. Such differences highlight the peculiarities of each mangrove and emphasize the need of specific management plans for ecosystem maintenance.

  17. Temporal trends of select pharmaceutical compounds entering an estuary from a small, urban river

    Science.gov (United States)

    The fate and effects of pharmaceutical compounds have been widely studied in freshwater systems; however, less is known about their behavior in marine ecosystems. In many coastal watersheds, there are river systems that are receiving waters for domestic wastewater treatment effl...

  18. A study of the management strategies for river aeolian dust inhibition at the estuary of Zhuo-shui River

    Science.gov (United States)

    Tsai, S. F.; Lin, C. Y.

    2014-12-01

    With the characteristics of humidity in summer and drought in winter, there existing lots of bare lands due to the decline of water level cause large amounts of aeolian dust and environmental deterioration during the monsoon seasons in central Taiwan. How to adopt effective measures to inhibit the damage of dust is an essential issue. This study selected the serious dust-affected section of Zhuo-shui river (bridge Zi-qiang to Xi-bin) to delineate the areas of potential aeolian dust occurrence, explore the relationship between elevation and water level determined from return period analysis, submit the countermeasures for dust inhibition at the bare lands and/or cultivated areas, and address the responsibilities of related authority offices for dust prevention by means of literature review. The return period of inundation for the areas of potential aeolian dust occurrence is 1.1 years. Engineering of dust prevention with highly unit price are not recommended due to could be destroyed annually. The deposition sites of a river are usually located at the convex bank, which with silt texture and high salinity are not suitable for cultivation, are delineated as the areas of potential aeolian dust occurrence. Besides technology consideration in dust prevention, this study also examined the related articles of river management to integrate a comprehensive vision for better riverside environment and air quality.

  19. Summer nutrients structure and phytoplankton growth under the influence of freshwater-saline water mixing in the Changjiang River Estuary

    Science.gov (United States)

    Liu, Ying; Wang, Kui; Chen, Jianfang

    2015-04-01

    The spatial distribution of NO3-, PO43-, SiO32- in summer were studied in the Changjiang (Yangtze River) Estuary and the adjacent East China Sea(ECS), the nutrients distribution was mainly controlled by the Changjiang dilution water and offshore seawater mixing. NO3-, PO43-, SiO32- were high west and low east, presenting two tongues shape nearshore. Combined with the nutrient structure difference along the estuary gradient, the potential relative nutrient limitation of surface water at each station was distinguished. Coastal water was featured with excess nitrogen, in summer DIN/P ratio was up to 160 in the frequent algae blooms area, while Si/N reached as low as 0.5, which could be caused by luxury consumption of P and Si by diatom bloom. For better understanding the process of nutrients structure variation and influence on phytoplankton growth under the Changjiang dilution water and seawater mixing, we also conducted field incubation simulating different fresh-saline water mixing scale, by 100%, 75%, 50%, 25% and 0% for about 3 days. The results were as follows: (1) The lower the percentage of freshwater, the lower the growth rate and pH increase rate of phytoplankton during the exponential growth period; (2) Macronutrients were apparently consumed. PO43- in the 100%, 75% and 50% dilution treatments were depleted within 48 h, suggesting that PO43- limit phytoplankton growth below salinity of 26. (3) For the 100% treatment the DIN/P ratio doubled as PO43- was consumed rapidly, while DIN decreased slowly. The DIN/Si ratio decreased to about 0.7 times the original level during the first 48 h, reflecting the lower initial DIN/Si value compared to the diatom uptake ratio (dDIN/dSi) during the incubation period. The incubation presented the phytoplankton growth extent and rate difference during fresh-saline water mixing, which makes nutrients gradient, and this mixing process may cause local blooms to change the nutrient structure, then might result in phytoplankton regime shift.

  20. Concentrations and fluxes of dissolved uranium in the Yellow River estuary: seasonal variation and anthropogenic (Water-Sediment Regulation Scheme) impact.

    Science.gov (United States)

    Juanjuan, Sui; Zhigang, Yu; Bochao, Xu; Wenhua, Dong; Dong, Xia; Xueyan, Jiang

    2014-02-01

    The Water-Sediment Regulation Scheme (WSRS) of the Yellow River is a procedure implemented annually from June to July to expel sediments deposited in Xiaolangdi and other large middle-reach reservoirs and to scour the lower reaches of the river, by controlling water and sediment discharges. Dissolved uranium isotopes were measured in river waters collected monthly as well as daily during the 2010 WSRS (June 19-July 16) from Station Lijin (a hydrologic station nearest to the Yellow River estuary). The monthly samples showed dissolved uranium concentrations of 3.85-7.57 ?g l(-1) and (234)U/(238)U activity ratios of 1.24-1.53. The concentrations were much higher than those reported for other global major rivers, and showed seasonal variability. Laboratory simulation experiments showed significant uranium release from bottom and suspended sediment. The uranium concentrations and activity ratios differed during the two stages of the WSRS, which may reflect desorption/dissolution of uranium from suspended river sediments of different origins. An annual flux of dissolved uranium of 1.04 × 10(8) g y(-1) was estimated based on the monthly average water discharge and dissolved uranium concentration in the lower reaches of the Yellow River. The amount of dissolved uranium (2.65 × 10(7) g) transported from the Yellow River to the sea during the WSRS constituted about 1/4 of the annual flux. PMID:24292394

  1. Influence of river discharge on plankton metabolic rates in the tropical monsoon driven Godavari estuary, India

    Digital Repository Service at National Institute of Oceanography (India)

    Sarma, V.V.S.S.; Gupta, S.N.M.; Babu, P.V.R.; Acharyya, T.; Harikrishnachari, N.; Vishnuvardhan, K.; Rao, N.S.; Reddy, N.P.C.; Sarma, V.V.; Sadhuram, Y.; Murty, T.V.R.; Kumar, M.D.

    and exchange with the open ocean. Particularly watersheds (Meybeck 1982; Kemp 1984, Howarth et al. 1996) export significant amounts of organic matter to the system. Besides the externally supplied organic carbon, the active biological pump in coastal regions... contributes to significant accumulation of carbon in sediments (Wollast and Mackenzie 1989; Wollast 1998; Smith and Hollibaugh 1993). River-borne organic matter, mainly in dissolved form, is expected to be refractory (Meybeck, 1982) and is mostly unavailable...

  2. Nitrification and Nitrifying Bacteria in the Lower Seine River and Estuary (France)

    OpenAIRE

    Cébron, Aurélie; Berthe, Thierry; Garnier, Josette

    2003-01-01

    The Achères wastewater treatment plant, located just downstream of Paris, discharges its effluents into the lower Seine River. The effluents contain large numbers of heterotrophic bacteria, organic matter, and ammonium and are a source of nitrifying bacteria. As a result, degradation of organic matter by heterotrophic bacteria and subsequent oxygen depletion occur immediately downstream of the effluent outlet, whereas nitrifying bacteria apparently need to build up a significant biomass befor...

  3. Pair-Trawl Detection of PIT-Tagged Juvenile Salmonids Migrating in the Columbia River Estuary, 2008 Report of Research.

    Energy Technology Data Exchange (ETDEWEB)

    Magie, Robert J.; Morris, Matthew S.; Ledgerwood, Richard D. [Northwest Fisheries Science Center

    2009-06-03

    In 2008, we sampled migrating juvenile Pacific salmonids Oncorhynchus spp. tagged with passive integrated transponder (PIT) tags using a surface pair trawl in the upper Columbia River estuary (rkm 61-83). The cod-end of the trawl was replaced with a cylindrical PIT-tag detection antenna with an 86-cm-diameter fish-passage opening and two detection coils connected in series. The pair trawl was 105 m long with a 91.5-m opening between the wings and a sample depth of 4.9 m. Also during 2008, we finalized the development of a prototype 'matrix' antenna, which was larger than previous antennas by a considerable magnitude. The matrix antenna consisted of 6 coils: a 3-coil front component and a 3-coil rear component, which were separated by 1.5-m of net mesh. The fish-passage opening was 2.5 m wide by 3.0 m tall and was attached to a standard-size pair trawl net. Intermittent sampling with a single crew began on 7 March and targeted yearling Chinook salmon O. tshawytscha and steelhead O. mykiss. Daily sampling using two crews began on 30 April and continued through 14 June; during this period we detected 2.7% of all juvenile salmonids previously detected at Bonneville Dam--a measure of sample efficiency. Sampling with a single crew continued through 20 August and targeted subyearling Chinook salmon. We detected 7,397 yearling Chinook salmon, 2,735 subyearling Chinook salmon, 291 coho salmon O. kisutch, 5,950 steelhead, and 122 sockeye salmon O. nerka in the upper estuary. We deployed the matrix antenna system and the older, cylindrical antenna system (86-cm-diameter fish-passage opening) simultaneously in mid-May 2008 to test matrix detection efficiency. The cylindrical antenna system had been used successfully in 2007 and early 2008. Because distribution of migrating salmonids in the estuary changes rapidly, we felt that a tandem sampling effort between the two systems was the only way to truly evaluate comparative detection efficiency. We deployed both systems within 1 km of each other during a period of high fish densities on 13, 14, and 15 May. Detections of the matrix system surpassed those of the cylindrical system by 53% in 14 h of simultaneous sampling (total detections 716 and 339, respectively). We believe that the higher detection rate observed with the matrix system was due to fewer smolts escaping the trawl entrance and to more smolts readily passing through the larger fish-passage opening. After tandem sampling, we continued exclusive use of the matrix system for the remainder of the 2008 juvenile migration season. Mean survival rates from Lower Granite to Bonneville Dam for yearling Chinook salmon and steelhead were 42% (SE = 3.7%) and 46% (SE = 1.5%), respectively. Over 358,000 PIT-tagged salmonids were transported, and we detected 4,619 of these fish.

  4. Polycyclic aromatic hydrocarbons and risk to threatened and endangered Chinook salmon in the Lower Columbia River estuary.

    Science.gov (United States)

    Yanagida, Gladys K; Anulacion, Bernadita F; Bolton, Jennie L; Boyd, Daryle; Lomax, Daniel P; Paul Olson, O; Sol, Sean Y; Willis, Maryjean; Ylitalo, Gina M; Johnson, Lyndal L

    2012-02-01

    Polycyclic aromatic hydrocarbons (PAHs), derived from oil and fuel combustion, are ubiquitous nonpoint source pollutants that can have a number of detrimental effects on fish and wildlife. In this study, we monitored PAH exposure in outmigrant juvenile Chinook salmon from the Lower Columbia River to evaluate the risk that these contaminants might pose to the health and recovery of threatened and endangered salmonids. Juvenile Chinook salmon (Oncorhynchus tshawytscha) were collected by beach seine from five sites in the Lower Columbia River from Bonneville Dam to the mouth of the estuary (Warrendale, the Willamette-Columbia Confluence, Columbia City, Beaver Army Terminal, and Point Adams) and from a site in the Lower Willamette near downtown Portland (Morrison Street Bridge). Sediment samples were also collected at the same sites. Concentrations of PAHs in sediment samples were relatively low at all sites with average total PAH concentrations 10,000 ng/g wet wt. Metabolites of low and high molecular-weight PAHs were also detected in bile of salmon from all sites; for metabolites fluorescing at phenanthrene (PHN) wavelengths, concentrations ranged from 1.1 to 6.0 ?g/mg bile protein. Levels of PAHs in stomach contents and PAH metabolites in bile were highest in salmon from the Morrison Street Bridge site in Portland and the Willamette-Columbia Confluence, Columbia City, and Beaver Army Terminal sites. Mean PAH concentrations measured in some stomach content samples from the Columbia City, Beaver Army Terminal, and Morrison Street Bridge sites were near the threshold concentration (approximately 7200-7600 ng/g wet wt.) associated with variability and immune dysfunction in juvenile salmonids (Meador et al., Can J Fish Aquat Sci 63:2364-2376, 2006; Bravo et al., Environ Toxicol Chem 30:704-714, 2011). Mean levels of biliary fluorescent aromatic compounds (FACs)-PHN in juvenile Chinook collected at the Morrison Street Bridge site in Portland, at the Confluence and Columbia City sites, and at the Beaver Army Terminal site were at or above a threshold effect concentration of 2 ?g/mg protein for FACs-PHN linked to growth impairment, altered energetics, and reproductive effects (Meador et al., Environ Toxicol Chem 27(4):845-853, 2008). These findings suggest that PAHs in the food chain are a potential source of injury to juvenile salmon in the Lower Columbia and Lower Willamette rivers. PMID:21894559

  5. Mid-Holocene variability of the East Asian monsoon based on bulk organic ?13C and C/N records from the Pearl River estuary, southern China

    Science.gov (United States)

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

    2012-12-01

    Understanding the mid-Holocene dynamics of the East Asian monsoon (EAM) is integral to modelling the Holocene development of the global climate system (Webster et al., 1998). Thus the mid-Holocene EAM history was reconstructed using bulk organic carbon isotopes (?13C), total carbon to total nitrogen (C/N) ratios and total organic carbon (TOC) from a sediment core (UV1), at a mean resolution of 7-10 years, from the Pearl River estuary, southern China. Sedimentary ?13C, C/N and TOC from the Pearl River estuary is a good indicator of changes in monsoonal precipitation strength (Zong et al., 2006; Yang et al., 2010; Yu et al., 2010), eg sediments buried during a period of high precipitation exhibit a high proportion of terrigenous sediments, and have low ?13C and high C/N, and vice versa (Yu et al., 2010). Results suggest a general decreasing trend in monsoonal precipitation from 6650 to 2215 cal yr BP because of the weakening Northern Hemisphere insolation most likely related to the current precession circle (An, 2000). Superimposed on this trend are apparent dry-wet oscillations at centennial to millennial timescales most likely in response to solar activity. Mismatch between ?13C and results from the Dongge Cave in southern China at millennial-timescale oscillations (Wang et al., 2005), may indicate that the ?13C from the Pearl River estuary reveals changes in precipitation in a broader area than the ?18O from Dongge Cave does. Reference An Z (2000) The history and variability of the East Asian paleomonsoon climate. Quaternary Science Reviews 19: 171-187. Wang Y, Cheng H, Edwards RL, He Y, Kong X, An Z, Wu J, Kelly MJ, Dykoski CA and Li X (2005) The Holocene Asian Monsoon: Links to Solar Changes and North Atlantic Climate. Science 308: 854-857. Webster PJ, Magaña VO, Palmer TN, Shukla J and Tomas RA (1998) Monsoons: Processes, predictability, and the prospects for prediction. Journal of Geophysical Research 103(C7): 14451-14510. Yang S, Tang M, Yim WWS, Zong Y, Huang G, Switzer AD and Saito Y (2011) Burial of organic carbon in Holocene sediments of the Zhujiang (Pearl River) and Changjiang (Yangtze River) estuaries. Marine Chemistry 123(1-4): 1-10. Yu F, Zong Y, Lloyd JM, Huang G, Leng MJ, Kendrick C, Lamb AL and Yim WWS (2010) Bulk organic ?13C and C/N as indicators for sediment sources in the Pearl River delta and estuary, southern China. Estuarine, Coastal and Shelf Science 87(4): 618-630. Zong Y, Lloyd JM, Leng MJ, Yim WW-S and Huang G (2006) Reconstruction of Holocene monsoon history from the Pearl River Estuary, southern China, using diatoms and carbon isotope ratios. The Holocene 16(2): 251-263.

  6. Research Note:Effects of human activities on the Yangtze River suspended sediment flux into the estuary in the last century

    Directory of Open Access Journals (Sweden)

    S. L. Yang

    2004-01-01

    Full Text Available The surface erosion area in the Yangtze River basin increased from 364×103 km2 in the 1950s to 707×103 km2 in 2001 due to a great increase in population. Based on the regression relationship between surface erosion area and population, the surface erosion area was predicted to be about 280×103 km2 at the beginning of the 20th century. The sediment yield, which increased by about 30% during the first six decades of the 20th century, was closely related to the surface erosion area in this river basin. The Yangtze annual suspended sediment flux into the estuary was about 395×106 t a-1 at the beginning of the century, and this gradually increased to an average of 509×106 t a-1 in the 1960s. The increase in the suspended sediment flux into the estuary was accelerated in the 1950s and the 1960s due to the rapid increase in population and land use immediately after the Second World War and the Liberation War. After the riverine suspended sediment flux reached its maximum in the 1960s, it decreased to 6 t a-1 in 2003. Construction of dams was found to be the principal cause for this decreasing trend because, during the same period, (a the riverine water discharge did not show a decreasing trend, (b water diversion was not influential and (c sedimentation in lakes and canals of the middle and lower reaches did not increase. The total storage capacity of reservoirs has increased dramatically over the past half century. The amount of sediment trapped in reservoirs has increased to more than half a billion t a-1. As a result, the suspended sediment flux into the estuary dramatically decreased, even though the sediment yield from many areas of the basin increased in recent decades. Human activities gradually increased the suspended sediment flux into the estuary before the 1960s and then rapidly decreased it. The last century was a period when the Yangtze suspended sediment flux into the estuary was dramatically affected by human activities. Keywords: riverine sediment flux, human activities, surface erosion, dam, Yangtze (Changjiang River

  7. Occurrence, population dynamics and habitat characterization of Mytella guyanensis (Lamarck, 1819 (Mollusca, Bivalvia in the Paraíba do Norte river estuary

    Directory of Open Access Journals (Sweden)

    Alberto Kioharu Nishida

    1995-01-01

    Full Text Available A survey of Mytellaguyanensis occurrence and population dynamics were performed in the Paraíba do Norte river estuary. The characterization and the influence of temperature, salinity and substrate, as well as the associated fauna and flora on the population were also examined. Mytella guyanensis lives buried in the substrate of the mangrove intertidal zone of the Paraíba do Norte river estuary, from the mouth to 24 km upriver. Average annual density of this bivalve species was 5.2 individuals per m², with a predominantly aggregated distribution. The most frequent size was between 4.5 and 5.5 cm in length. Analysis of the substrate demonstrated the presence of two types of substrates in relation to the percentage of silt and clay and the water content. Besides interfering in the population density, the substrate heterogeneity may be a decisive factor in aggregation. Eight species of crustacean decapods and one bivalve species were identified as associated fauna.A ocorrência de M, guyanensis no estuário do Rio Paraíba do Norte foi mapeada, determinando-se sua presença ao longo dos afluentes e ilhas aí existentes. O estudo da dinâmica da população foi realizado em área protegida da Ilha da Restinga, coletando-se os animais ao longo de 37 transecções. A cada mês foram feitos 60 lançamentos com um delimitador de 0,1 m², sobre uma ou mais transecções. Todo o substrato foi retirado juntamente com os exemplares de M. guyanensis e a fauna associada, até a profundidade de 10 cm. A triagem dos exemplares menores foi feita por peneiramento do substrato. O tipo de substrato foi anotado a cada lançamento. Dois tipos de substrato estão presentes na área: um substrato de tipo consistente, constituido por 89.7% de silte e argila e 10.3% de areia fina e outro de tipo não consistente contendo 74.5% de silte e argila e 25.5% de areia fina. O substrato de tipo não consistente apresenta quantidade de água significativamente maior que o de tipo consistente. Mytella guyanensis vive enterrada no solo numa profundidade máxima de 1,0 cm, sempre envolvida pelos filamentos do bisso. A densidade média anual observada para a espécie foi de 5,2 indivíduos por m²; a distribuição espacial predominante foi do tipo agregado, sofrendo interferência do tipo de substrato presente. Houve preferência de fixação da espécie pelo substrato do tipo consistente. Animais entre 4,5 e 5,5 cm de comprimento ocorrem o ano todo, sendo mais numerosos aqueles com comprimento entre 4,5 e 5,0 cm. A presença de formas jovens foi assinalada em baixa frequência em alguns meses do ano. A salinidade da água estuarina variou de acordo com o regime pluviométrico da região, permanecendo dentro dos níveis de tolerância da espécie. A fauna associada está representada por oito espécies de crustáceos e por uma de molusco bivalve.

  8. The impact of poultry litter application on sediment chemistry of the Broadkill River estuary system, Delaware.

    Science.gov (United States)

    Oyewumi, Oluyinka; Schreiber, Madeline E; Ciparis, Serena

    2014-01-01

    This project examined the impact of long-term poultry litter application on the chemical signatures of As, Cu, Zn, and P in stream sediments of the Broadkill River watershed within the Delmarva Peninsula, a region of intense poultry production. Thirty-seven sediment samples were collected from Broadkill River drainage systems and analyzed for litter-derived elements (As, Cu, Zn, P) and basic soil parameters such as particle size distribution, organic matter, and soluble salts. Results showed that concentrations of elements in stream sediments are approximately log-normally distributed. Spatial variability in concentrations of elements was evident, with most elements increasing in concentration and enrichment from upgradient headwaters to downgradient reaches draining predominantly agricultural areas. Results of correlation analyses showed positive significant correlation among elements; elements were also positively correlated with percent clay and silt in the sediment. Using GIS maps with overlays of hydrology and land use activities, statistical correlations between As, Cu, Zn, and P enrichment factors and land use were examined. Results showed statistically significant relationships between As, Mn, and Zn enrichment factors and residential areas within the watershed, but did not show a statistically significant relationship between element enrichment factors and agricultural land use. Factors that complicate this type of landscape-scale study include the presence of poultry processing plants, impoundments, changes in land use over time, and the influence of tides, all of which can have direct and indirect influences on element mobility. PMID:23925863

  9. Ionised silica in the estuary of a river as supply to seawater: Identification and ionization efficiency of silica species by FAB-MS

    Science.gov (United States)

    Tanaka, Miho; Takahashi, Kazuya

    2013-04-01

    Measurement of the dissolution state of silicic acid is difficult. In river water, silica exists in particle form, but silica particles with a diameter of less than approximately 0.45 ?m are considered as dissolved silica. In seawater, silica exists in two forms: ionic silica and particle silica. In this study, we focused on ionic silica. Using fast atom bombardment mass spectrometry (FAB-MS), the silica species in river water and seawater were detected as ionic forms. Ionic silica forms various chemical species in aquatic solutions, including the monomer ([Si]) and dimer ([Si]). The relative abundances of these species in aquatic solutions depend on the chemical and physical conditions. Silica species such as [Si(OH)2O2Na]- ([monomer-Na+]-), [Si2(OH)5O2]- ([dimer]-), [Si2(OH)4O3Na]-([dimer-Na+]-), [Si4(OH)7O5]- ([cyclic tetramer]-), [Si4(OH)6O6Na]- ([cyclic tetramer-Na+]-), [Si4(OH)9O4]- ([linear tetramer]-) and [Si4(OH)8O5Na]- ([linear tetramer-Na+]-) were directly observed by FAB-MS in river water and seawater. Some of these ionic silica species are expected to serve as "nutrients" for diatoms in seawater. Large silica particles are transported in river water, whereas in estuaries, a large amount of silica is precipitated and a small amount of silica is dissolved as ionic forms in sodium chloride solution. In river water, the concentration of silica was high, but the ionic silica species were hardly ionised by FAB-MS. In seawater, the concentration of silica was low, but the ionic silica species were well ionised. Thus, the ionization efficiency of silica species by FAB-MS indicates the type of silica species. The filtration process of silicic acid and the ionization of silicic acid to dissolve the silica species in seawater, which is an electrolyte (sodium chloride), occur in the estuary of a river. Thus, the estuary of a river plays an important role in the restructuring of silica from particle form to ionic form.

  10. [Diurnal variations of greenhouse gas fluxes at the water-air interface of aquaculture ponds in the Min River estuary].

    Science.gov (United States)

    Yang, Ping; Tong, Chuan; He, Qing-Hua; Huang, Jia-Fang

    2012-12-01

    Wetland reclamation and aquaculture is one of the main disturbance types in coastal wetlands. Diurnal variations of CO2, CH4 and N2O fluxes at the water-air interface were determined using a floating chambers + gas chromatography method in a shrimp pond, and a mixed culture pond of fish and shrimp in October in the Shanyutan Wetland of the Min River estuary, southeast China. Meanwhile, the meteorological indicators in ground surface and physical, chemical and biological indicators of surface water were also measured. CO2, CH4 and N2O fluxes at the water-air interface all demonstrated distinct diurnal variations. Both shrimp pond and mixed culture pond of fish and shrimp functioned as a sink of CO2 [the diurnal averaged CO2 fluxes were -48.79 and -105.25 mg x (m2 x h)(-1), respectively], and a source of CH4 [the diurnal averaged CH4 fluxes were 1.00 and 5.74 mg x (m2 x h)(-1), respectively]; the diurnal averaged CO2 and CH4 fluxes at the water-air interface of the mixed culture of fish and shrimp pond were higher than that of the shrimp pond. Greenhouse gas fluxes at the water-air interface from the aquaculture ponds were influenced by many factors. Multiple stepwise regression analysis showed that the concentration of Chlorophyll was the major factor affecting the CO2 fluxes, and the concentrations of SO4(2-) and PO4(3-) were the major factors affecting the CH4 fluxes at the water-air interface of the shrimp pond; whereas water temperature and Chlorophyll were the major factors affecting the CO2 fluxes, and dissolved oxygen, PO4(3-) and pH were the major factors affecting the CH4 fluxes at the water-air interface of the mixed culture pond of fish and shrimp. PMID:23379142

  11. Sinking rates of phytoplankton in the Changjiang (Yangtze River) estuary: A comparative study between Prorocentrum dentatum and Skeletonema dorhnii bloom

    Science.gov (United States)

    Guo, Shujin; Sun, Jun; Zhao, Qibiao; Feng, Yuanyuan; Huang, Daji; Liu, Sumei

    2016-02-01

    Sinking rates of phytoplankton community with variable taxonomic composition in the offshore Changjiang (Yangtze River) estuary were measured during two cruises in spring and summer, 2011. A homogenous-sample method SETCOL was used to determine the sinking rates. Phytoplankton community was dominated by dinoflagellates in spring and diatoms in summer, and two species Prorocentrum dentatum and Skeletonema dorhnii formed algal blooms in the survey area during the two cruises, respectively. Phytoplankton sinking rates ranged from 0.13 to 1.04 m day- 1 (average = 0.61 ± 0.24 m day- 1) in spring and 0.28 to 1.71 m day- 1 (average = 0.80 ± 0.34 m day- 1) in summer. In the surface layer, phytoplankton sinking rates at the P. dentatum bloom stations in spring were lower than that at the S. dorhnii bloom stations in summer. No significant correlation was found between phytoplankton sinking rates and most of the environmental parameters during the two cruises, except for temperature and nitrite concentration in summer. A significant correlation was observed between phytoplankton sinking rates and phytoplankton community structure in the surface layers: the higher dominance of diatom in the phytoplankton community corresponded to higher phytoplankton sinking rate. Therefore, the phytoplankton community structure other than the environmental parameters, is the important factor to affect the sinking rates greatly. The consequent carbon flux caused by phytoplankton sinking was estimated, and results suggested that the carbon flux to bottom water during the S. dorhnii bloom (average = 63.13 ± 48.16 mg C m- 2 day- 1) in summer was about 2.4 fold of that during the P. dentatum bloom (average = 26.10 ± 26.25 mg C m- 2 day- 1) in spring. These findings provide us some insight in understanding the carbon export contributed by marine phytoplankton in the coastal sea, where frequent phytoplankton blooms and high following carbon export occur.

  12. Migrational Characteristics, Biological Observations, and Relative Survival of Juvenile Salmonids Entering the Columbia River Estuary, 1966-1983, 1985 Final Report of Research.

    Energy Technology Data Exchange (ETDEWEB)

    Dawley, Earl M.

    1986-04-01

    Natural runs of salmonids in the Columbia River basin have decreased as a result of hydroelectric-dam development, poor land- and forest-management, and over-fishing. This has necessitated increased salmon culture to assure adequate numbers of returning adults. Hatchery procedures and facilities are continually being modified to improve both the efficiency of production and the quality of juveniles produced. Initial efforts to evaluate changes in hatchery procedures were dependent upon adult contributions to the fishery and returns to the hatchery. Procedures were developed for sampling juvenile salmon and steelhead entering the Columbia River estuary and ocean plume. The sampling of hatchery fish at the terminus of their freshwater migration assisted in evaluating hatchery production techniques and identifying migrational or behavioral characteristics that influence survival to and through the estuary. The sampling program attempted to estimate survival of different stocks and define various aspects of migratory behavior in a large river, with flows during the spring freshet from 4 to 17 thousand cubic meters per second (m/sup 3//second).

  13. Diversity and distribution of amoA-type nitrifying and nirS-type denitrifying microbial communities in the Yangtze River estuary

    Science.gov (United States)

    Zhang, Y.; Xie, X.; Jiao, N.; Hsiao, S. S.-Y.; Kao, S.-J.

    2014-04-01

    Coupled nitrification-denitrification plays a critical role in the removal of excess nitrogen, which is chiefly caused by humans, to mitigate estuary and coastal eutrophication. Despite its obvious importance, limited information about the relationships between nitrifying and denitrifying microbial communities in estuaries, and their controlling factors have been documented. We investigated the nitrifying and denitrifying microbial communities in the estuary of turbid subtropical Yangtze River (YRE), the largest river in Asia, by analyzing the ammonia monooxygenase gene amoA, including archaeal and bacterial amoA, and the dissimilatory nitrite reductase gene nirS using clone libraries and quantitative PCR (qPCR). The diversity indices and rarefaction analysis revealed a quite low diversity for both ?-proteobacterial and archaeal amoA genes, but qPCR data showed significantly higher amoA gene copy numbers for archaea than ?-proteobacteria. Compared with the amoA gene, a significantly higher level of diversity but lower gene copy numbers were found for the nirS gene. Nitrification and denitrification rates based on 15N incubation experiments supported gene abundance data as denitrification rates were below detection limit, suggesting lower denitrification than nitrification potential. In general, the abundances of the amoA and nirS genes were significantly higher in the bottom samples than the surface ones, and in the high-turbidity river mouth, were significantly higher in the particle-associated (> 3 ?m) than the free-living (0.2 ~ 3 ?m) communities. Notably, positive correlations between the amoA and nirS gene abundances suggested potential gene-based coupling between nitrification and denitrification, especially for the particle-associated assemblages. Statistical analysis of correlations between the community structure, gene abundances and environmental variables further revealed that dissolved oxygen and total suspended material might be the key factors controlling community spatial structure and regulating nitrification and denitrification potentials in the YRE ecosystem.

  14. Prediction of the effects of nutrient loadings from a power plant at Perryman on the water quality of the Bush River estuary. Final report

    International Nuclear Information System (INIS)

    A water-quality model consisting of a one-dimensional Hydraulic Module coupled with a Water Quality Module was used to assess the effects of increased nutrient loadings from the proposed Perryman Power Plant on the dissolved oxygen and chlorophyll-a concentrations in the Bush River estuary. The Hydraulic Module represented the longitudinal water movement (and physical transport of associated constituents) among 12 spatial segments. The Water Quality Module represented the biological processes affecting nitrogen, phosphorus, chlorophyll-a, and dissolved oxygen in each segment (e.g., photosynthesis, nutrient uptake, decomposition)

  15. Investigation of sediment movement in the North Navigation Channel Area of the estuary of the Yangtze river using natural radiotracers and INAA methods

    International Nuclear Information System (INIS)

    This is a preliminary investigation of sediment in the North Navigation Channel Area of the estuary of the Yangtze river, which has been made by determining the natural radioisotopes and the INAA of 30 natural sand samples. Multivariate statistical method was used to process and analyze the data obtained. It can be seen that there are tow sediment movement routes in the investigation area. The orientation of the main sediment movement is from northwest to southeast in accordance with the results obtained from the field submarine drag-monitorings after the radiotracer injection. Besides, there is also another sand movement route existed. (author). 5 refs., 3 figs., 4 tabs

  16. Cycling of transuranic radionuclides in the Columbia River, its estuary and the northeast Pacific Ocean. Progress report, February 1979-February 1980

    International Nuclear Information System (INIS)

    This report summarizes progress from February 1979 through January 1980 on the measurement of radionuclides in the Columbia River and its estuary, with principal emphasis on transuranic radionuclides. Accomplishments and pertinent findings of the 3 year interval are summarized and future directions for the research are presented. The first part of the report will draw on information contained in the previous two submissions as well as results from this contract year. This will hopefully present a synoptic view for outside reviewers and the Department of Energy

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

    Science.gov (United States)

    Fok, Lincoln; Cheung, P K

    2015-10-15

    Large plastic (>5mm) and microplastic (0.315-5mm) debris were collected from 25 beaches along the Hong Kong coastline. More than 90% consisted of microplastics. Among the three groups of microplastic debris, expanded polystyrene (EPS) represented 92%, fragments represented 5%, and pellets represented 3%. The mean microplastic abundance for Hong Kong was 5595items/m(2). This number is higher than international averages, indicating that Hong Kong is a hotspot of marine plastic pollution. Microplastic abundance was significantly higher on the west coast than on the east coast, indicating that the Pearl River, which is west of Hong Kong, may be a potential source of plastic debris. The amounts of large plastic and microplastic debris of the same types (EPS and fragments) were positively correlated, suggesting that the fragmentation of large plastic material may increase the quantity of beach microplastic debris. PMID:26233305

  18. Soil organic matter and soil acidity in Mangrove areas in the river Paraiba Estuary, Cabedelo, Paraiba, Brazil

    Directory of Open Access Journals (Sweden)

    Renata Wilma Vasconcelos

    2014-08-01

    Full Text Available Mangrove ecosystems are of great environmental significance, because of their fragility and role in feeding and breeding various animal species. In northeastern Brazil, the disorderly occupation of estuarine areas and the urban sprawl have led to a considerable loss of the original area occupied by mangroves. In the municipality of Cabedelo, State of Paraíba, there are about 4,900 ha of remnant mangrove areas in the estuarine complex of the Paraíba River. However, information about the attributes of mangrove soils at this location is quite scarce. The aim of this study was to quantify the soil organic matter and soil acidity in mangroves located in the estuary of the Paraíba River, State of Paraíba, Brazil, in order to increase the database of soil attributes in this region. The study area is in local influence of the Restinga de Cabedelo National Forest (Flona, an environmental conservation unit of the Chico Mendes Institute for Biodiversity Conservation. For the choice of sampling points, we considered an area that receives direct influence of the eviction of domestic and industrial effluents. The soil of the study area is an “Organossolo Háplico” in Brazilian Soil Classification (Histosol, and was sampled at four point sites: one upstream of the effluent discharge (P1, one in the watercourse receiving effluent water (P2, one downstream of the effluent discharge (P3 and another near Flona (P4, at 0-20 and 20-40 cm, in four replications in time (28/08/2012 in the morning and afternoon, and 21/01/2013 in the morning and afternoon. Potential acidity, pH and soil organic matter (SOM were determined. No significant differences were detected in the potential acidity of the four collection sites, which ranged from 0.38 to 0.45 cmolc dm-3. Soil pH was greatest at point P4 (7.0 and lowest at point P1 (5.8. The SOM was highest at point P1 (86.4 % and lowest at P2 (77.9 %. The attributes related to soil acidity were not sensitive to indicate differences in the environments we evaluated, and seem not to indicate the contamination of mangroves by discharge of sewage into water bodies that border these environments. The high organic matter content of soils in the mangrove may have helped avoid significant fluctuations in soil acidity, because of the large buffering capacity.

  19. Seasonal stratification and property distributions in a tropical estuary (Cochin estuary, west coast, India)

    Digital Repository Service at National Institute of Oceanography (India)

    Shivaprasad, A.; Vinita, J.; Revichandran, C.; Reny, P.D.; Deepak, M.P.; Muraleedharan, K.R.; NaveenKumar, K.R.

    immune from extended hypoxia/anoxia and maintaining the health of the Cochin estuary. For the seasonally varying river flow in the estuary, salt intrusion receded with increasing river flow in monsoon and rebounded with decreasing river flow in dry season...

  20. Hazard Assessment from Storm Tides and Rainfall on a Tidal River Estuary

    Science.gov (United States)

    Orton, P.; Conticello, F.; Cioffi, F.; Hall, T.; Georgas, N.; Lall, U.; Blumberg, A.

    2015-01-01

    Here, we report on methods and results for a model-based flood hazard assessment we have conducted for the Hudson River from New York City to Troy/Albany at the head of tide. Our recent work showed that neglecting freshwater flows leads to underestimation of peak water levels at up-river sites and neglecting stratification (typical with two-dimensional modeling) leads to underestimation all along the Hudson. As a result, we use a three-dimensional hydrodynamic model and merge streamflows and storm tides from tropical and extratropical cyclones (TCs, ETCs), as well as wet extratropical cyclone (WETC) floods (e.g. freshets, rain-on-snow events). We validate the modeled flood levels and quantify error with comparisons to 76 historical events. A Bayesian statistical method is developed for tropical cyclone streamflows using historical data and consisting in the evaluation of (1) the peak discharge and its pdf as a function of TC characteristics, and (2) the temporal trend of the hydrograph as a function of temporal evolution of the cyclone track, its intensity and the response characteristics of the specific basin. A k-nearest-neighbors method is employed to determine the hydrograph shape. Out of sample validation tests demonstrate the effectiveness of the method. Thus, the combined effects of storm surge and runoff produced by tropical cyclones hitting the New York area can be included in flood hazard assessment. Results for the upper Hudson (Albany) suggest a dominance of WETCs, for the lower Hudson (at New York Harbor) a case where ETCs are dominant for shorter return periods and TCs are more important for longer return periods (over 150 years), and for the middle-Hudson (Poughkeepsie) a mix of all three flood events types is important. However, a possible low-bias for TC flood levels is inferred from a lower importance in the assessment results, versus historical event top-20 lists, and this will be further evaluated as these preliminary methods and results are finalized. Future funded work will quantify the influences of sea level rise and flood adaptation plans (e.g. surge barriers). It would also be valuable to examine how streamflows from tropical cyclones and wet cool-season storms will change, as this factor will dominate at upriver locations.

  1. Modeling ecosystem processes with variable freshwater inflow to the Caloosahatchee River Estuary, southwest Florida. II. Nutrient loading, submarine light, and seagrasses

    Science.gov (United States)

    Buzzelli, Christopher; Doering, Peter; Wan, Yongshan; Sun, Detong

    2014-12-01

    Short- and long-term changes in estuarine biogeochemical and biological attributes are consequences of variations in both the magnitude and composition of freshwater inputs. A common conceptualization of estuaries depicts nutrient loading from coastal watersheds as the stressor that promotes algal biomass, decreases submarine light penetration, and degrades seagrass habitats. Freshwater inflow depresses salinity while simultaneously introducing colored dissolved organic matter (color or CDOM) which greatly reduces estuarine light penetration. This is especially true for sub-tropical estuaries. This study applied a model of the Caloosahatchee River Estuary (CRE) in southwest Florida to explore the relationships between freshwater inflow, nutrient loading, submarine light, and seagrass survival. In two independent model series, the loading of dissolved inorganic nitrogen and phosphorus (DIN and DIP) was reduced by 10%, 20%, 30%, and 50% relative to the base model case from 2002 to 2009 (2922 days). While external nutrient loads were reduced by lowering inflow (Q0) in the first series (Q0 series), reductions were accomplished by decreasing the incoming concentrations of DIN and DIP in the second series (NP Series). The model also was used to explore the partitioning of submarine light extinction due to chlorophyll a, CDOM, and turbidity. Results suggested that attempting to control nutrient loading by decreasing freshwater inflow could have minor effects on water column concentrations but greatly influence submarine light and seagrass biomass. This is because of the relative importance of Q0 to salinity and submarine light. In general, light penetration and seagrass biomass decreased with increased inflow and CDOM. Increased chlorophyll a did account for more submarine light extinction in the lower estuary. The model output was used to help identify desirable levels of inflow, nutrient loading, water quality, salinity, and submarine light for seagrass in the lower CRE. These findings provide information essential to the development of a resource-based approach to improve the management of both freshwater inflow and estuarine biotic resources.

  2. Coupling the chemical dynamics of carbonate and dissolved inorganic nitrogen systems in the eutrophic and turbid inner Changjiang (Yangtze River Estuary

    Directory of Open Access Journals (Sweden)

    W.-D. Zhai

    2015-04-01

    Full Text Available To better understand biogeochemical processes controlling CO2 dynamics in those eutrophic large-river estuaries and coastal lagoons, we investigated surface water carbonate system, nutrients, and relevant hydrochemical parameters in the inner Changjiang (Yangtze River Estuary, covering its channel-like South Branch and the lagoon-like North Branch, shortly after a spring-tide period in April 2010. In the North Branch, with a water residence time of more than 2 months, biogeochemical additions of ammonium (7.4 to 65.7 ?mol kg?1 and alkalinity (196 to 695 ?mol kg?1 were detected along with high salinity of 4.5 to 17.4. In the South Branch upper-reach, unusual salinity values of 0.20 to 0.67 were detected, indicating spillover waters from the North Branch. The spillover waters enhanced the springtime Changjiang export fluxes of nutrients, dissolved inorganic carbon, and alkalinity. And they affected the biogeochemistry in the South Branch, by lowering water-to-air CO2 flux and continuing the nitrification reaction. In the North Branch, pCO2 was measured from 930 to 1518 ?atm at the salinity range between 8 and 16, which was substantially higher than the South Branch pCO2 of 700 to 1100 ?atm. Based on field data analyses and simplified stoichiometric equations, we suggest that the North Branch CO2 productions were quantified by biogeochemical processes combining organic matter decomposition, nitrification, CaCO3 dissolution, and acid-base reactions in the estuarine mixing zone. Although our study is subject to limited temporal and spatial coverage of sampling, we have demonstrated a procedure to quantificationally constrain net CO2 productions in eutrophic estuaries and/or coastal lagoons, by coupling the chemical dynamics of carbonate and dissolved inorganic nitrogen systems.

  3. Natural activity in Hudson River estuary samples and their influence on the detection limits for gamma emitting radionuclides using NaI gamma spectrometry

    International Nuclear Information System (INIS)

    Sources of natural radioactivity in Hudson River Estuary are described. The technique of analysis for gamma spectrometry of environmental samples is presented and its pros and cons discussed. The distribution of natural radioactivity in water, biota and sediment was reported as well as the role played by the vertical distribution of cesium-137 in sediments as an indicator of the rate of sedimentation. The effect of the presence of natural radionuclides on the detection limits of man-made nuclides in the Hudson River environment is thoroughly examined. The results obtained with a 4-in. sodium iodide well crystal housed in a low background mercury shielding compare favorably with a more sophisticated Ge(Li) system which uses anticoincidence, as far as the analysis of environmental samples is concerned. (U.S.)

  4. An eight year (2005-2013) temporal trend of halogenated organic pollutants in fish from the Pearl River Estuary, South China.

    Science.gov (United States)

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

    2015-04-15

    Dichlorodiphenyltrichloroethane and its metabolites (DDTs), hexachlorocyclohexanes (HCHs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), dechlorane plus (DP), 2,3,5,6-tetrabromo-p-xylene (pTBX) and pentabromotoluene (PBT) were measured in baby croaker (Collichthys lucidus) and mullet (Osteomugil ophuyseni) collected in 2005 and 2013 from the Pearl River Estuary. DDTs, HCHs, PCBs, and PBDEs were detected in two fish species at concentrations of 150-8100, 1.4-120, 22-560, 2.2-280 ng/g lipid wt., respectively. The levels of these chemicals were significantly lower in 2013 than in 2005. The compositions for DDTs, HCHs, and PBDEs in 2013 differed from those in 2005, indicating source changes between the two sampling periods. DP, pTBX and PBT were detected at concentrations of ND-130 ng/g lipid wt. No clear temporal trends were found for these contaminants. Overall, these results indicated the effectiveness of regulations and source controls in substantively reducing inputs of these contaminants to the Pearl River Estuary. PMID:25769908

  5. Living in an estuary: Commerson's dolphin (Cephalorhynchus commersonii (Lacépède, 1804, habitat use and behavioural pattern at the Santa Cruz River, Patagonia, Argentina

    Directory of Open Access Journals (Sweden)

    Rocio Loizaga de Castro

    2013-11-01

    Full Text Available Commerson's dolphins, Cephalorhynchus commersonii, suffer bycatch in fisheries and are target of dolphin-watching activities along Patagonia. Here we described dolphins' habitat use and behavioural pattern at the estuary of Santa Cruz River. Behavioural observations were made from vantage points using a spotting scope. Boat surveys were conducted randomly from Puerto Santa Cruz to the mouth of the river to analyze the habitat use. The survey area was divided into 1 km² cells and characterized with depth and benthic slope. The described behaviours for the Commerson's dolphin were: travelling, slow travelling, milling, resting, socializing, stationary swimming and diving. A new behavioural context was assigned to diving, a behaviour that showed a high frequency during downing tide, suggesting a benthic foraging strategy. Additionally, we found a strong influence of the tide on Commerson's dolphin behaviour. Habitat use models indicated that dolphins prefer shallow water inside the estuary. The knowledge of the behavioural patterns and the habitat use of these endemic species, in this unexplored area, provide tools for management and conservation purposes.

  6. Model Behavior and Sensitivity in an Application of the Cohesive Bed Component of the Community Sediment Transport Modeling System for the York River Estuary, VA, USA

    Directory of Open Access Journals (Sweden)

    Kelsey A. Fall

    2014-05-01

    Full Text Available The Community Sediment Transport Modeling System (CSTMS cohesive bed sub-model that accounts for erosion, deposition, consolidation, and swelling was implemented in a three-dimensional domain to represent the York River estuary, Virginia. The objectives of this paper are to (1 describe the application of the three-dimensional hydrodynamic York Cohesive Bed Model, (2 compare calculations to observations, and (3 investigate sensitivities of the cohesive bed sub-model to user-defined parameters. Model results for summer 2007 showed good agreement with tidal-phase averaged estimates of sediment concentration, bed stress, and current velocity derived from Acoustic Doppler Velocimeter (ADV field measurements. An important step in implementing the cohesive bed model was specification of both the initial and equilibrium critical shear stress profiles, in addition to choosing other parameters like the consolidation and swelling timescales. This model promises to be a useful tool for investigating the fundamental controls on bed erodibility and settling velocity in the York River, a classical muddy estuary, provided that appropriate data exists to inform the choice of model parameters.

  7. Model behavior and sensitivity in an application of the cohesive bed component of the community sediment transport modeling system for the York River estuary, VA, USA

    Science.gov (United States)

    Fall, Kelsey A.; Harris, Courtney K.; Friedrichs, Carl T.; Rinehimer, J. Paul; Sherwood, Christopher R.

    2014-01-01

    The Community Sediment Transport Modeling System (CSTMS) cohesive bed sub-model that accounts for erosion, deposition, consolidation, and swelling was implemented in a three-dimensional domain to represent the York River estuary, Virginia. The objectives of this paper are to (1) describe the application of the three-dimensional hydrodynamic York Cohesive Bed Model, (2) compare calculations to observations, and (3) investigate sensitivities of the cohesive bed sub-model to user-defined parameters. Model results for summer 2007 showed good agreement with tidal-phase averaged estimates of sediment concentration, bed stress, and current velocity derived from Acoustic Doppler Velocimeter (ADV) field measurements. An important step in implementing the cohesive bed model was specification of both the initial and equilibrium critical shear stress profiles, in addition to choosing other parameters like the consolidation and swelling timescales. This model promises to be a useful tool for investigating the fundamental controls on bed erodibility and settling velocity in the York River, a classical muddy estuary, provided that appropriate data exists to inform the choice of model parameters.

  8. Population structure, size at maturity and condition of sardine, Sardina pilchardus (Walb., 1792), in the nursery ground of the eastern Adriatic Sea (Krka River Estuary, Croatia)

    Science.gov (United States)

    Sinov?i?, Gorenka; Ke?, Vanja ?ikeš; Zorica, Barbara

    2008-03-01

    A total of 1125 specimens of sardine, Sardina pilchardus, ranging in total length from 4.9 to 12.5 cm (mean 8.31 ± 1.41 cm) and in weights between 1.02 g and 11.18 g (mean 4.40 ± 1.87 g) were randomly sampled using a beach seine from the Krka River estuary. Samples were collected monthly according to their occurrence in this area from October to February during 2002/03, 2003/04 and 2004/05, which is during the spawning period of this species. Monthly fluctuations in the length frequency distributions of sardine were observed during that time. The length-weight relationship of all sardine specimens was described by the equation: W=0.007L( r2 = 0.9626); and the isometric nature of relative growth was established ( t = -5.1495; p sardine specimens were in better somatic condition at the beginning of their appearance (spawning period) in the Krka River estuary. The length at which 50% of sardines were mature ( L50) was calculated to be 7.9 cm.

  9. Monitoring of persistent organic pollutants in seawater of the Pearl River Estuary with rapid on-site active SPME sampling technique.

    Science.gov (United States)

    Huang, Siming; He, Shuming; Xu, Hao; Wu, Peiyan; Jiang, Ruifen; Zhu, Fang; Luan, Tiangang; Ouyang, Gangfeng

    2015-05-01

    An on-site active solid-phase microextraction (SPME) sampling technique coupled with gas chromatography-mass spectrometry (GC-MS) for sampling and monitoring 16 polycyclic aromatic hydrocarbons (PAHs) and 8 organochlorine pesticides (OCPs) in seawater was developed. Laboratory experiments demonstrated that the sampling-rate calibration method was practical and could be used for the quantification of on-site sampling. The proposed method was employed for field tests which covered large amounts of water samples in the Pearl River Estuary in rainy and dry seasons. The on-site SPME sampling method can avoid the contamination of sample, the losses of analytes during sample transportation, as well as the usage of solvent and time-consuming sample preparation process. Results indicated that the technique with the designed device can address the requirement of modern environment water analysis. In addition, the sources, bioaccumulation and potential risk to human of the PAHs and OCPs in seawater of the Pearl River Estuary were discussed. PMID:25732847

  10. Dynamics of nitrous oxide reductase genes (nosZ) in intertidal rocky biofilms and sediments of the Douro River estuary (Portugal), and their relation to N-biogeochemistry.

    Science.gov (United States)

    Magalhães, C; Bano, N; Wiebe, W J; Bordalo, A A; Hollibaugh, J T

    2008-02-01

    In this study, temporal variability of nosZ genotypes was evaluated in two intertidal rocky biofilms and two intertidal sediment sites of the Douro River estuary, Portugal. The results were compared to rates of key N-cycle processes and environmental variables to examine possible links between denitrifier community dynamics and N biogeochemistry. Genetic heterogeneity of the nosZ gene was evaluated by terminal restriction fragment length polymorphism analysis (T-RFLP) and by sequencing cloned nosZ gene fragments. Phylogenetic analysis showed that the majority of the nosZ genes detected were most similar to nosZ genes from isolates affiliated with alpha-subclass of the class Proteobacteria. Results revealed low nosZ genotype richness, and hierarchical cluster analysis showed significant differences in the composition of denitrifier communities that inhabit different intertidal environments of the Douro River estuary. Monthly surveys of nosZ genotypes from sandy sediments showed that, while the same T-RFLP peaks were present in all samples, shifts in the relative peak areas of the different nosZ genotypes occurred. Canonical correspondence analysis, based on data from the monthly survey, revealed a strong relationship between the relative peak areas of some T-RFLP operational taxonomic units (OTUs) with denitrification rate and NO3- availability. Results suggest that denitrifiers with specific nosZ genotypes (OTUs) have competitive advantage over others when NO3- fluctuates in the system; these fluctuations reflect, in turn, variability in denitrification rates. PMID:17604988

  11. Characterization of heavy-metal contamination in surface sediments of the Minho river estuary by way of factor analysis.

    Science.gov (United States)

    Mil-Homens, M; Costa, A M; Fonseca, S; Trancoso, M A; Lopes, C; Serrano, R; Sousa, R

    2013-05-01

    Surface sediments were collected in August 2009 from 49 sites along the Minho estuary (between Tui and Caminha) and analyzed for grain size, organic carbon (Corg) and total nitrogen (Ntot) contents, and major (silicon [Si], aluminum [Al], iron [Fe], calcium [Ca], magnesium [Mg], sodium [Na], potassium [K], titanium [Ti], and mangesese [Mn]) and trace element (arsenic [As], chromium [Cr], copper [Cu], mercury [Hg], lithium [Li], lead [Pb], rubidium [Rb], tin [Sn], and zinc [Zn]) concentrations. Factor analysis was used to decrease 22 selected variables into 4 factors accounting for 85.9 % of the total variance explained, suggesting distinct elemental sources or sediment components affecting their spatial distributions. Although factors 1 (detrital component; elements strongly associated with fine- [Na, Mg, Ti, Li, Cr, Cu, Fe, Al, Zn, Ca, and As] and coarse-grained sediments [Si, K, Rb; mean grain-size [MGS]) and 3 (Fe-Mn oxyhydroxide sediment component; Fe, Mn, As, fine fraction) are interpreted as reflecting predominance of natural contributions, factors 2 (urban and industrial contamination: sediment components [Pb, Hg, organic carbon [Corg], total nitrogen [Ntot] and 4 (components associated with contamination by nautical activities; the association of tin [Sn] and calcium [Ca]) seem to indicate anthropogenic contributions). Nevertheless, the influence of elemental contributions derived from tungsten (W)-Sn mineralizations and those resulting from mining activities can also contribute to the obtained geochemical associations and should be considered. Spatial distribution of dominant factor scores shows the dominance of factors 2 and 4 between Tui and Vila Nova de Cerveira, whereas samples dominated by factors 3 and 1 are found between Ilha da Boega and Seixas and in the Caminha areas, respectively. Despite the dominance of factor score 1 in the Caminha area, the distribution pattern of dominant factor scores shows samples dominated by other factor scores that can be explained by dredging activities in this river sector that restore ancient sedimentary characteristics or expose contaminated sediments. Through the identification of sample locations dominated by factors associated with contamination, it will be possible to select them as priority areas where new environmental (e.g., toxicity tests, organic Sn compounds, tracers of sewage contamination) studies should be implemented in the future. PMID:23299253

  12. Evaluating sedimentation rates in the estuary and shelf region of the Paraíba do Sul River, Southeastern Brazil

    Scientific Electronic Library Online (English)

    Cristiana V. A., Wanderley; José Marcus, Godoy; Maria Luiza D. P., Godoy; Carlos Eduardo, Rezende; Luiz D., Lacerda; Isabel, Moreira; Zenildo L., Carvalho.

    2014-01-01

    Full Text Available Este estudo é uma avaliação das taxas de sedimentação na região do delta do Rio Paraíba do Sul e sua correlação com a forte erosão que ocorre em Atafona, Rio de Janeiro. Os resultados obtidos são baseados 14 testemunhos de sedimentos, com um total de aproximadamente 540 amostras, coletados em janeir [...] o de 2010 e fevereiro de 2011. Os inventários de 210Pb nos pontos de amostragem ao sul da desembocadura do Rio Paraíba do Sul foram maiores do que aqueles observados para os pontos de coleta na região norte e central, o que sugere que os sedimentos são transportados ao longo da costa com as correntes nesta direção. Os resultados da datação 210Pb foram validados com base na variação de concentração elementar ao longo de dois dos testemunhos. Concentrações de Cd e Zn aumentaram significativamente em 1982 e atingindo valores máximos (0,5 mg kg-1 e 139 mg kg-1, respectivamente) em 1984. Estes máximos correspondem ao acidente da indústria Cia Paraibuna de Metais, que ocorreu em 1982. Abstract in english This study aims to evaluate sedimentation rates in the Paraíba do Sul estuary and its shelf regions. These sedimentation rates were correlated with strong erosion occurring in Atafona, Rio de Janeiro. The results were based on four transects, from which 14 sediment cores with approximately 540 sedim [...] ent samples were collected in January 2010 and February 2011. At sampling points south of the Paraíba do Sul River (PSR) mouth, 210Pb inventories were higher than those at the northern and central sampling locations, suggesting that sediment is transported southward by the alongshore current. The 210Pb dating results were validated based on the elemental concentration variation throughout two of the sediment cores. Heavy metal concentrations, such as Cd and Zn, increased significantly in 1982 and reached maximum values (0.5 mg kg-1 and 139 mg kg-1, respectively) in 1984. These maxima correspond to the Cia Paraibuna de Metais industry accident, which occurred in 1982.

  13. Experimental simulation of antimony and chromium forms of residence in the water of the Syr-Darya river, estuary and in the water of the Aral Sea usng sup(124)Sbsup((5)) and sup(51)Crsup((6)) radionuclides

    International Nuclear Information System (INIS)

    Using the compbination of radiochemical methods, the physicochemical state of sup(124)Sbsup((5)) and sup(51)Crsup((6)) in the waters of the Syr-Darya river, estuary and the Aral Sea is studied. It is ascertained, that in the river, estuary and Aral Sea water the main amount of sup(124)Sbsup((5)) and sup(51)Crsup((6)) migrates in the form of negatively charged anions Sb(OH)6- and CrOsub(4)sup(2-). However, in the Aral Sea estuary the formation of finely dispersed colloid forms of chromium (6) and antimony (5) is possible due to their sorption on vegetable cellulose, modified by arid water components. There is also a possibility of appearance of antimony (5) sorptional forms on other sorbents in a narrow range of the Aral Sea water salinity

  14. Sources and accumulation of organic carbon in the Pearl River Estuary surface sediment as indicated by elemental, stable carbon isotopic, and carbohydrate compositions

    Science.gov (United States)

    He, B.; Dai, M.; Huang, W.; Liu, Q.; Chen, H.; Xu, L.

    2010-10-01

    Organic matter in surface sediments from the upper reach of the Pearl River Estuary and Lingdingyang Bay, as well as the adjacent northern South China Sea shelf was characterized using a variety of techniques, including elemental (C and N) ratio, bulk stable organic carbon isotopic composition (?13C), and carbohydrate composition analyses. Total organic carbon (TOC) content was 1.21±0.45% in the upper reach, down to 1.00±0.22% in Lingdingyang Bay and to 0.80±0.10% on the inner shelf and 0.58±0.06% on the outer shelf. ?13C values ranged from -25.1‰ to -21.3‰ in Lingdingyang Bay and the South China Sea shelf, with a trend of enrichment seawards. The spatial trend in C/N ratios mirrored that of ?13C, with a substantial decrease in C/N ratio offshore. Total carbohydrate yields ranged from 22.1 to 26.7 mg (100 mg OC)-1, and typically followed TOC concentrations in the estuarine and shelf sediments. Total neutral sugars, as detected by the nine major monosaccharides (lyxose, rhamnose, ribose, arabinose, fucose, xylose, galactose, mannose, and glucose), were between 4.0 and 18.6 mg (100 mg OC)-1 in the same sediments, suggesting that significant amounts of carbohydrates were not neutral aldoses. Using a two end-member mixing model based on ?13C values and C/N ratios, we estimated that the terrestrial organic carbon contribution to the surface sediment TOC was ca. 78±11% for Lingdingyang Bay, 34±4% for the inner shelf, and 5.5±1% for the outer shelf. The molecular composition of the carbohydrate in the surface sediments also suggested that the inner estuary was rich in terrestrially derived carbohydrates but that their contribution decreased offshore. A relatively high abundance of deoxyhexoses in the estuary and shelf indicated a considerable bacterial source of these carbohydrates, implying that sediment organic matter had undergone extensive degradation and/or transformation during transport. Sediment budget based on calculated regional accumulation rates showed that only ~50% of the influxes of terrestrial organic carbon were accumulated in the estuary. This relatively low accumulation efficiency of terrestrial organic matter as compared to the total suspended solids (accumulation efficiency ~73%) suggested significant degradation of the terrestrial organic carbon within the estuarine system after its discharge from the river. This study demonstrated that the combination of the bulk organic matter properties together with the isotopic composition and molecular-level carbohydrate compositions can be an efficient way to track down the source and fate of organic matter in highly dynamic estuarine and coastal systems. The predominance of terrestrially originated organic matter in the sediment and its generally low accumulation efficiency within the estuary is not surprising, and yet it may have important implications in light of the heavy anthropogenic discharges into the Pearl River Estuary during the past thirty years.

  15. Caracterización hidrográfica del estuario del río Valdivia, centro-sur de Chile / Hydrographic features of Valdivia river estuary south-central Chile

    Scientific Electronic Library Online (English)

    José, Garcés-Vargas; Marcela, Ruiz; Luis Miguel, Pardo; Sergio, Nuñez; Iván, Pérez-Santos.

    2013-03-01

    Full Text Available La costa sureste del Océano Pacífico entre 37° y 41°S, se caracteriza por la presencia de un gran número de estuarios micromareales (rango mareal menor a 2 m). Uno de los estuarios más importantes dentro de estas latitudes es el estuario del río Valdivia, cuya estructura y dinámica termal y halina e [...] s poco conocida. Mediante mediciones hidrográficas de temperatura y salinidad tomadas durante un ciclo estacional anual y el análisis de sus principales forzantes (marea, caudal del río, vientos y radiación solar) se explica la variabilidad así como sus cambios en la estratificación vertical. El análisis de la estructura termohalina de la columna de agua reveló que el estuario varió estacionalmente comportándose como un estuario de cuña salina en invierno y primavera producto del mayor caudal de los ríos afluentes, mientras que en verano y otoño se comportó como parcialmente mezclado, producto del menor caudal de los ríos. En invierno y primavera la columna de agua presentó inversión térmica, la cual fue asociada a pérdida de calor superficial y a la advección sub-superficial de aguas cálidas desde el océano adyacente hacia el interior del estuario que no se mezclaron con las de la superficie debido a la intensa estratificación salina. El cambio en el régimen estuarino de cuña salina a parcialmente mezclado según la estación del año y presencia de la inversión térmica estacional, son características hidrográficas necesarias tanto para la implementación de esfuerzos de conservación de hábitat vulnerables presentes en la zona (áreas de crianza de juveniles de especies explotadas), como para la utilización de este sistema para actividades de acuicultura y manejo de recursos marinos. Abstract in english The area between 37° and 41°S of the southeastern Pacific coast, have a great number of microtidal (tidal range less than 2 m) estuaries. One of the most important estuaries in these latitudes is the Valdivia River estuary, whose thermal and haline structure is poorly known. Thus, this work, through [...] hydrographic measurements of temperature and salinity taken during an annual seasonal cycle and the analysis of the main forcings (tide, river flow, wind and solar radiation) explain the variability and its changes in vertical stratification. The analysis of the the thermohaline structure of the water column revealed that the estuary varied seasonally behaving like a salt-wedge estuary in winter and spring due to a higher flow of tributaries. However, in summer and autumn behaved as partially mixed due the lower river flow. In winter and spring the water column showed a temperature inversion which was associated with a large surface heat loss and subsurface advection of warm waters from the adjacent ocean to into the estuary that is not mixed with the surface due to intense stratification by salinity. The change in the estuarine salt-wedge regime to partially mixed according to the season and the presence of thermal inversion seasonal are necessary hydrographic features to implement conservation efforts of vulnerable habitat into the zone (nursery areas of juvenile species), and use of this system for aquaculture activities and marine resources management.

  16. Sources and accumulation of organic carbon in the Pearl River Estuary surface sediment as indicated by elemental, stable carbon isotopic, and carbohydrate compositions

    Directory of Open Access Journals (Sweden)

    B. He

    2010-10-01

    Full Text Available Organic matter in surface sediments from the upper reach of the Pearl River Estuary and Lingdingyang Bay, as well as the adjacent northern South China Sea shelf was characterized using a variety of techniques, including elemental (C and N ratio, bulk stable organic carbon isotopic composition (?13C, and carbohydrate composition analyses. Total organic carbon (TOC content was 1.21±0.45% in the upper reach, down to 1.00±0.22% in Lingdingyang Bay and to 0.80±0.10% on the inner shelf and 0.58±0.06% on the outer shelf. ?13C values ranged from ?25.1‰ to ?21.3‰ in Lingdingyang Bay and the South China Sea shelf, with a trend of enrichment seawards. The spatial trend in C/N ratios mirrored that of ?13C, with a substantial decrease in C/N ratio offshore. Total carbohydrate yields ranged from 22.1 to 26.7 mg (100 mg OC?1, and typically followed TOC concentrations in the estuarine and shelf sediments. Total neutral sugars, as detected by the nine major monosaccharides (lyxose, rhamnose, ribose, arabinose, fucose, xylose, galactose, mannose, and glucose, were between 4.0 and 18.6 mg (100 mg OC?1 in the same sediments, suggesting that significant amounts of carbohydrates were not neutral aldoses. Using a two end-member mixing model based on ?13C values and C/N ratios, we estimated that the terrestrial organic carbon contribution to the surface sediment TOC was ca. 78±11% for Lingdingyang Bay, 34±4% for the inner shelf, and 5.5±1% for the outer shelf. The molecular composition of the carbohydrate in the surface sediments also suggested that the inner estuary was rich in terrestrially derived carbohydrates but that their contribution decreased offshore. A relatively high abundance of deoxyhexoses in the estuary and shelf indicated a considerable bacterial source of these carbohydrates, implying that sediment organic matter had undergone extensive degradation and/or transformation during transport. Sediment budget based on calculated regional accumulation rates showed that only ~50% of the influxes of terrestrial organic carbon were accumulated in the estuary. This relatively low accumulation efficiency of terrestrial organic matter as compared to the total suspended solids (accumulation efficiency ~73% suggested significant degradation of the terrestrial organic carbon within the estuarine system after its discharge from the river. This study demonstrated that the combination of the bulk organic matter properties together with the isotopic composition and molecular-level carbohydrate compositions can be an efficient way to track down the source and fate of organic matter in highly dynamic estuarine and coastal systems. The predominance of terrestrially originated organic matter in the sediment and its generally low accumulation efficiency within the estuary is not surprising, and yet it may have important implications in light of the heavy anthropogenic discharges into the Pearl River Estuary during the past thirty years.

  17. Assessing the Influence of Nonpoint Source and Discharge Changes on Water Quality in a Tidal River Estuary Using a Three-Dimensional Model

    Directory of Open Access Journals (Sweden)

    Wen-Cheng Liu

    2014-11-01

    Full Text Available The change of nonpoint source and freshwater discharge as a result of land use change might affect the water quality in a river. In the current study, a coupled three-dimensional hydrodynamic and water quality model was created and applied to the Danshuei River estuarine system and its adjacent coastal ocean. The hydrodynamic and water quality models were validated using observations of water surface elevation, salinity distribution and water quality state variables. The predictions of hydrodynamics, salinity, dissolved oxygen and nutrients from the model simulation quantitatively agreed with the observational data. The validated model was then used to investigate the possible effects of the nonpoint source and freshwater discharge changes at the upstream reaches on water quality conditions in the Danshuei River estuarine system. Three scenarios were investigated to predict the dissolved oxygen using model simulations. The simulated results indicated that increasing nonpoint sources at the upstream reaches degraded the dissolved oxygen under low flow conditions. However, increasing freshwater discharges at the upstream reaches would overcome the loadings of the nonpoint source, which would result in increasing the dissolved oxygen in the tidal river estuary. The model can provide a useful tool for developing management practices for nonpoint sources to protect the water quality in the estuarine system.

  18. Levels of C{sub 10}-C{sub 13} polychloro-n-alkanes in marine mammals from the Arctic and the St. Lawrence River estuary

    Energy Technology Data Exchange (ETDEWEB)

    Tomy, G.T.; Muir, D.C.G.; Stern, G.A.; Westmore, J.B.

    2000-05-01

    Marine mammals from various regions of the Arctic and the St. Lawrence River estuary were examined for the first time for levels of C{sub 10}--C{sub 13} polychloro-n-alkanes (sPCAs). Respective mean total sPCA concentrations in the blubber of beluga whales (Delphinapterus leucas) from Saqqaq and Nuussuaq, western Greenland, were 0.23 {+-} 0.02 (n = 2) and 0.164 {+-} 0.06 {micro}g/g (n = 2), similar to that in beluga from the Mackenzie Delta in the western Canadian Arctic 0.21 {+-} 0.08 {micro}g/g (m = 3). sPCAs levels were higher in beluga blubber from the St. Lawrence River (0.37 to 1.4 {micro}g/g). Mean sPCA concentrations in the blubber samples from walruses (Odobenus rosmarus) (Thule, northwest Greenland) and ringed seal (Phoca hispida) (Eureka, southwest Ellesmere Island) were 0.43 {+-} 0.06 (n = 2) and 0.53 {+-} 0.2 {micro}g/g (n = 6), respectively. Relative to commercial sPCA formulations, samples from the Arctic marine mammals showed a predominance of the shorter chain length lower percent chlorinated PCA congeners, the more volatile components of industrial formulations. This observation is consistent with long-range atmospheric transport of sPCAs to this region. The profiles of the belugas from the St. Lawrence River estuary, however, had higher proportions of the less volatile sPCA congeners, implying that contamination to this region is probably from local sources.

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

    Digital Repository Service at National Institute of Oceanography (India)

    Kessarkar, P.M.; Shynu, R.; Rao, V.P.; Chong, F.; Narvekar, T.; Zhang, J.

    , where ore deposits are stored on the shore, exhibit high Fe, Mn, total rare earth elements (total REE), and middle REE- and heavy REE-enriched patterns. Channel stations of both estuaries exhibit middle REE- and light REE-enriched patterns, which...

  20. Satellite Remote Sensing of Chlorophyll a in Support of Nutrient Management in the Neuse and Tar-Pamlico River Estuaries

    Science.gov (United States)

    The North Carolina Environmental Management Commission (EMC) has adopted as a water quality standard that chlorophyll a concentration should not exceed 40 ug/L in sounds, estuaries and other slow-moving waters. Exceedances require regulators to develop a Total Maximum Daily Limit...

  1. Artificial radionuclides in French estuaries

    International Nuclear Information System (INIS)

    Measurements were made of 238Pu, sup(239-240)Pu, 241Am, 137Cs, 144Ce, 106Ru, 125Sb and 131I in the principal rivers and estuaries of France (Seine, Loire, Gironde, Rhone). The mean specific activities due to sup(239-240)Pu in river water suspensions (5 to 10 fCi/g) are very little affected by releases from nuclear power stations. The unexpectedly high 238Pu/sup(239-240)Pu activity ratios (0.15 to 0.25) found in media subject only to atmospheric fall-out results from fractionation in the catchment areas. The high artificial radionuclide activities measured in the Seine estuary are attributed to releases from Windscale and, above all, from La Hague. The 137Cs found in Gironde river water remains associated with particles in the estuary. It decreases downstream by ion exchange in the estuary of the Loire, whereas in the Seine estuary the values recorded are higher than upstream owing to the effects of marine contamination. Particulate sup(239-240)Pu increases in all cases between the river and the estuary, a result which is in line with its frequent deficit in solution. However, the transfer of dissolved fluvial sup(239-240)Pu (0.05 to 0.2 fCi/ltr) cannot account for the excess in the particulate phase, the origin of which is ascribed to dissolved marine plutonium. (author)

  2. Investigation into the response of the auditory and acoustic communications systems in the Beluga whale (Delphinapterus leucas) of the St. Lawrence River Estuary to noise, using vocal classification

    Science.gov (United States)

    Scheifele, Peter Martin

    2003-06-01

    Noise pollution has only recently become recognized as a potential danger to marine mammals in general, and to the Beluga Whale (Delphinapterus leucas) in particular. These small gregarious Odontocetes make extensive use of sound for social communication and pod cohesion. The St. Lawrence River Estuary is habitat to a small, critically endangered population of about 700 Beluga whales who congregate in four different sites in its upper estuary. The population is believed to be threatened by the stress of high-intensity, low frequency noise. One way to determine whether noise is having an effect on an animal's auditory ability might be to observe a natural and repeatable response of the auditory and vocal systems to varying noise levels. This can be accomplished by observing changes in animal vocalizations in response to auditory feedback. A response such as this observed in humans and some animals is known as the Lombard Vocal Response, which represents a reaction of the auditory system directly manifested by changes in vocalization level. In this research this population of Beluga Whales was tested to determine whether a vocalization-as-a-function-of-noise phenomenon existed by using Hidden Markhov "classified" vocalizations as targets for acoustical analyses. Correlation and regression analyses indicated that the phenomenon does exist and results of a human subjects experiment along with results from other animal species known to exhibit the response strongly implicate the Lombard Vocal Response in the Beluga.

  3. Potential remobilization of 137Cs, 60Co, 90Tc, and 90Sr from contaminated Mayak sediments in river and estuary environments.

    Science.gov (United States)

    Standring, William J F; Oughton, Deborah H; Salbu, Brit

    2002-06-01

    Following 50 years of nuclear production at Mayak PA, sediments in storage reservoirs are significantly contaminated. Dam failure or flooding could potentially transport large amounts of sediments, via rivers, to the Ob estuary and Kara Sea. The objectives of this work were to investigate fresh and seawater remobilization of 137Cs, 50Co, 99Tc, and 90Sr from contaminated Reservoir 10 sediments. Sediments were extracted sequentially using synthetic Techa freshwater, seawater, and chemical reagents with increasing dissolution powers. 137Cs and 90Sr freshwater distribution coefficients (apparent Kd) agreed quite well with published values; values for 99Tc were higher and values for 60Co were lower than expected. In seawater, mean apparent Kd values decreased by 94, 77, 48, and 73% (137Cs, 60Co, 99Tc, and 90Sr, respectively), indicating increased radionuclide mobility. Remobilization in seawater was 5, 15, 1, and 23% of total activities (i.e., releases of 165, 11, 0.3, and 170 kBq kg(-1) d.w.) for 137Cs, 60Co, 99Tc, and 90Sr, respectively. 137Cs and 99Tc were strongly bound to sediments (60% and 80%, respectively). 60Co and 90Sr were more mobile (70% reversibly bound). In conclusion, Mayak Reservoir sediments could potentially contaminate the Ob estuary due to remobilization of sediment-held radionuclides upon contact with seawater. PMID:12075786

  4. Short-term changes and longitudinal distribution of carbon metabolism in the Piauí River estuary (Sergipe, Brazil) Variações de curto prazo e distribuição longitudinal do metabolismo do carbono no estuário do Rio Piauí (Sergipe, Brasil)

    OpenAIRE

    SOUZA M. F. L. de; E. C. G. COUTO

    1999-01-01

    Net pelagic metabolism (NPM) and net ecosystem metabolism (NEM) were assessed by sigmaCO2 changes in three sampling stations along Piauí River estuary. At the upper estuary station, sampling was carried out over 48 h. Samples exhibited high DIN:DIP ratios. Chlorophyll-a ranged from 0.2 to 2.5 mug.l-1, being higher at the upper estuarine station than marine ones. Net pelagic metabolic rates ranged from -13.2 to 61.2 mgC.m7-2.d-1. Presence of mucilaginous algal material can explain the net mine...

  5. Design and Analysis of Salmonid Tagging Studies in the Columbia Basin : Evaluating Wetland Restoration Projects in the Columbia River Estuary using Hydroacoustic Telemetry Arrays to Estimate Movement, Survival, and Residence Times of Juvenile Salmonids, Volume XXII (22).

    Energy Technology Data Exchange (ETDEWEB)

    Perry, Russell W.; Skalski, John R.

    2008-08-01

    Wetlands in the Columbia River estuary are actively being restored by reconnecting these habitats to the estuary, making more wetland habitats available to rearing and migrating juvenile salmon. Concurrently, thousands of acoustically tagged juvenile salmonids are released into the Columbia River to estimate their survival as they migrate through the estuary. Here, we develop a release-recapture model that makes use of these tagged fish to measure the success of wetland restoration projects in terms of their contribution to populations of juvenile salmon. Specifically, our model estimates the fraction of the population that enter the wetland, survival within the wetland, and the mean residence time of fish within the wetland. Furthermore, survival in mainstem Columbia River downstream of the wetland can be compared between fish that remained the mainstem and entered the wetland. These conditional survival estimates provide a means of testing whether the wetland improves the subsequent survival of juvenile salmon by fostering growth or improving their condition. Implementing such a study requires little additional cost because it takes advantage of fish already released to estimate survival through the estuary. Thus, such a study extracts the maximum information at minimum cost from research projects that typically cost millions of dollars annually.

  6. Status of the population structure of the mangrove crab Ucides cordatus (Decapoda: Ocypodidae on the Piraquê-açu River estuary, Espírito Santo, Brazil

    Directory of Open Access Journals (Sweden)

    Rita de Cássia Conti

    2010-06-01

    Full Text Available The land crab Ucides cordatus is a keystone species of neotropical mangrove forests and an important resource of the artisanal fisheries. The spatial and temporal distribution of U. cordatus in the mangrove area of the Piraquê-açu river estuary was determined following a longitudinal estuarine salinity gradient (lower, middle, upper estuary and along the vertical intertidal gradient. The numbers of open and closed burrows were counted monthly on fixed transects, the inhabiting crabs were caught, sexed and the carapace width measured, during 1 year. The mean crab density was 2.5 ind.m-². The highest crab density (3.9 ind.m-², linked to high numbers of juvenile crabs, was found on the upper estuary and correlated with lower salinities. High intertidal levels had higher crab densities than lower intertidal levels, except in the upper estuary. Males were smaller than females; the mean carapace width of the population was 4.89 cm, below the minimum legal harvesting size (6 cm. The predominance of females over males at some sites (especially close to villages brought out the advanced level of overfishing of this U. cordatus population and highlights the urgent need of management actions.O caranguejo Ucides cordatus é uma espécie chave nos manguezais da região neotropical e um importante recurso pesqueiro para populações tradicionais. A distribuição espacial e temporal de U. cordatus no manguezal do Rio Piraquê-açu foi estudada ao longo de um gradiente de salinidade, no estuário inferior, médio e superior na faixa entre-marés. Mensalmente durante um ano. O número de tocas abertas e fechadas ao longo de transectos fixos, foi contado mensalmente, ao longo de um ano, e os caranguejos capturados foram sexados e medidos quanto à largura da carapaça, sendo posteriormente liberados. A densidade média de caranguejos foi de 2,5 ind.m-². A maior densidade (3,9 ind.m-², juntamente com o maior número de jovens, foi encontrada na parte superior do estuário, correlacionada com baixas salinidades. Nos níveis mais altos de maré a densidade de caranguejos sempre foi alta, exceto na região superior do estuário. Os machos foram menores do que as fêmeas; o tamanho médio da carapaça da população total foi de 4,89 cm, abaixo do tamanho legal permitido para captura (6 cm. A predominância de fêmeas sobre machos em alguns pontos, principalmente próximos às vilas, revela o avançado nível de sobreexplotação da população de U. cordatus, evidenciando a necessidade urgente de ações fiscalizadoras.

  7. Status of the population structure of the mangrove crab Ucides cordatus (Decapoda: Ocypodidae) on the Piraquê-açu River estuary, Espírito Santo, Brazil

    Scientific Electronic Library Online (English)

    Rita de Cássia, Conti; Rosebel Cunha, Nalesso.

    2010-06-01

    Full Text Available O caranguejo Ucides cordatus é uma espécie chave nos manguezais da região neotropical e um importante recurso pesqueiro para populações tradicionais. A distribuição espacial e temporal de U. cordatus no manguezal do Rio Piraquê-açu foi estudada ao longo de um gradiente de salinidade, no estuário inf [...] erior, médio e superior na faixa entre-marés. Mensalmente durante um ano. O número de tocas abertas e fechadas ao longo de transectos fixos, foi contado mensalmente, ao longo de um ano, e os caranguejos capturados foram sexados e medidos quanto à largura da carapaça, sendo posteriormente liberados. A densidade média de caranguejos foi de 2,5 ind.m-². A maior densidade (3,9 ind.m-²), juntamente com o maior número de jovens, foi encontrada na parte superior do estuário, correlacionada com baixas salinidades. Nos níveis mais altos de maré a densidade de caranguejos sempre foi alta, exceto na região superior do estuário. Os machos foram menores do que as fêmeas; o tamanho médio da carapaça da população total foi de 4,89 cm, abaixo do tamanho legal permitido para captura (6 cm). A predominância de fêmeas sobre machos em alguns pontos, principalmente próximos às vilas, revela o avançado nível de sobreexplotação da população de U. cordatus, evidenciando a necessidade urgente de ações fiscalizadoras. Abstract in english The land crab Ucides cordatus is a keystone species of neotropical mangrove forests and an important resource of the artisanal fisheries. The spatial and temporal distribution of U. cordatus in the mangrove area of the Piraquê-açu river estuary was determined following a longitudinal estuarine salin [...] ity gradient (lower, middle, upper estuary) and along the vertical intertidal gradient. The numbers of open and closed burrows were counted monthly on fixed transects, the inhabiting crabs were caught, sexed and the carapace width measured, during 1 year. The mean crab density was 2.5 ind.m-². The highest crab density (3.9 ind.m-²), linked to high numbers of juvenile crabs, was found on the upper estuary and correlated with lower salinities. High intertidal levels had higher crab densities than lower intertidal levels, except in the upper estuary. Males were smaller than females; the mean carapace width of the population was 4.89 cm, below the minimum legal harvesting size (6 cm). The predominance of females over males at some sites (especially close to villages) brought out the advanced level of overfishing of this U. cordatus population and highlights the urgent need of management actions.

  8. Protist 18S rRNA gene Sequence Analysis Reveals Multiple Sources of Organic Matter Contributing to Turbidity Maxima of the Columbia River Estuary

    Energy Technology Data Exchange (ETDEWEB)

    Herfort, Lydie; Peterson, Tawnya D.; McCue, Lee Ann; Zuber, Peter A.

    2011-10-05

    The Columbia River estuary is traditionally considered a detritus-based ecosystem fueled in summer by organic matter (OM) from expired freshwater diatoms. Since Estuarine Turbidity Maxima (ETM) are sites of accumulation and transformation of this phytoplankton-derived OM, to further characterize the ETM protist assemblage, we collected in August 2007 bottom waters throughout an ETM event, as well as surface water during the peak of bottom turbidity, and performed biogeochemical, microscopic and molecular (18S rRNA gene clone libraries) analyses. These data confirmed that the majority of the particulate OM in ETMs is derived from chlorophyll a-poor particulate organic carbon tagged by DNA too damaged to be detected by molecular analysis.

  9. The distribution and speciation of trace metals in surface sediments from the Pearl River Estuary and the Daya Bay, Southern China

    International Nuclear Information System (INIS)

    Surface sediments collected from the Pearl River Estuary (PRE) and the Daya Bay (DYB) were analyzed for total metal concentrations and chemical phase partitioning. The total concentrations of Cr, Cu, Ni, Pb, and Zn in the PRE were obviously higher than those in DYB. The maximum concentrations of trace metals in DYB occurred in the four sub-basins, especially in Dapeng Cove, while the concentrations of these metals in the western side of the PRE were higher than those in the east side. Such distribution pattern was primarily due to the different hydraulic conditions and inputs of anthropogenic trace metals. The chemical partitioning of metals analyzed by the BCR sequential extraction method showed that Cr, Ni, and Zn of both areas were present dominantly in the residual fraction, while Pb was found mostly in the non-residual fractions. The partitioning of Cu showed a significant difference between the two areas.

  10. Decrease in chemical contamination of American eels anguilla rostrata captured in the estuary of the St. Lawrence River. Canadian technical report of fisheries and aquatic sciences No. 1876

    Energy Technology Data Exchange (ETDEWEB)

    Hodson, P.V.

    1992-01-01

    American eels are catadromous, and grow to maturity in Lake Ontario and in tributaries to the St. Lawrence River. Concern for mass mortalities of adult eels, high levels of chemical contamination, and a recent decline of recruitment prompted a study of the role of contaminants in the health of eels, the role of eels as vectors of contaminants to Beluga whales, and the changes in contamination since an earlier large scale survey in 1982. Mercury, PCBs, mirex, and pesticide levels were measured in migratory adult eels purchased weekly between September and November 1990 from a fisherman in Kamouraska, Quebec. Similar analyses were conducted on two eel samples from fishermen in Cacouna and Saint-Irenee, and on a control eel sample from a small tributary of the north shore of St. Lawrence Estuary. Dioxins, furans, and PAH concentrations were also determined on a small number of fish.

  11. Distribution and behaviour of 137Cs in nearshore sediments of the northern Adriatic and at the Adige River estuary, northern Italy

    International Nuclear Information System (INIS)

    This paper reports the results of determinations of 137Cs and other radionuclides in bottom sediments and suspended matter collected in a coastal zone of the northern Adriatic. The activity, behaviour and distribution of 137Cs and some natural radionuclides were determined in materials sampled up to 1984. Various artificial radionuclides were detected in samples collected in 1986. The study of the distribution of 137Cs as a function of sediment properties showed that this radionuclide preferentially accumulates in the finest particles and is taken up by adsorption surface processes. This radioisotope has been used as a tracer for recent sedimentary processes occurring in the study area for predicting the fate of other inorganic and organic pollutants reaching the sediments by natural processes. Exceptionally high values of radioactivity were observed after the Chernobyl accident in the estuary of the Adige River, particularly in suspended matter. (author)

  12. Plutonium, cesium and uranium series radionuclides in the Hudson River estuary and other environments. Annual technical progress report, 1 December 1980-30 November 1981

    International Nuclear Information System (INIS)

    Radionuclide activities were measured in sediment cores and suspended particle samples throughout the salinity range of the Hudson River estuary. Activities of 137Cs, 134Cs, 60Co, 239240Pu, and 238Pu indicate reasonably rapid accumulation rates in the sediments of marginal cove areas, and very rapid deposition in the harbor region adjacent to New York City, resulting in 239240Pu accumulations there more than an order of magnitude greater than the fallout delivery rate. Fallout 239240Pu reaching the Hudson is almost completely retained within the systems by particle deposition, while 80 to 90% of the 137Cs derived from both reactor releases and fallout is exported to the coastal waters in solution. Depth profiles of radionuclides in Hudson sediments are not significantly altered by physical mixing processes in the sediments in areas accumulating particles at greater than 1 cm/yr. Measurements of fallout 2392xperimental quantities

  13. Preliminary assessment of heavy metal levels in Mytella falcata (Bivalvia, Mytilidae from Bacanga River estuary, São Luis, State of Maranhão, Northeastern Brazil

    Directory of Open Access Journals (Sweden)

    CARVALHO G. P. de

    2000-01-01

    Full Text Available The concentrations of Cu, Zn, Pb, and Cd were determined in the mussel Mytella falcata from the Bacanga River estuary, in order to evaluate the potential role of domestic effluents released "in natura" on the quality of the estuarine environment with consequences to shellfish resources. Cu concentrations ranged from 5.2 mg.g-1 to 13.1 mg.g-1, while Zn concentrations ranged from 49.1 mg.g-1 to 76.3 mg.g-1. Pb and Cd showed concentrations lower than 2 mg.g-1. The results showed low concentrations of Cu, Pb and Cd in the filter-feeding Mytella falcata in the study area in comparison with the maximum values stablished to foods by the Brazilian Government (Decree Law Nº 55,871. Finally, Zn presented slightly higher values than the maximum ones stablished by the Brazilian government.

  14. Linking Species Traits to the Abiotic Template of Flowing Waters: Contrasting Eco physiologies Underlie Displacement of Zebra Mussels by Quagga Mussels in a Large River-Estuary

    Science.gov (United States)

    Casper, A. F.

    2005-05-01

    The St. Lawrence River-Estuary was the gateway of entry for dreissenids to North America and holds some of the oldest populations. The St. Lawrence also has four distinct physical-chemical water masses (a regional scale abiotic template) that both species inhabit. Despite their ecological similarities, quagga mussels are supplanting zebra mussels in much of their shared range. In order to try to better understand the changing distributions of these two species we compared glycogen, shell mass and tissue biomass in each of the water masses. This comparative physiological combined with experimental approaches (estuarine salinity experiments and reciprocal transplants) showed that while quagga mussels should dominate in most habitats, that abiotic/bioenergetic constraints in two regions (the Ottawa River plume and the freshwater-marine transition zone) might prevent them from dominating these locations. These findings are an example of how the interaction of landscape scale abiotic heterogeneity and a species-specific physiology can have strong impacts of distribution of biota large rivers.

  15. Hydrophysical and hydrochemical characteristics of the sea areas adjacent to the estuaries of small rivers of the Russian coast of the Black Sea

    Science.gov (United States)

    Zavialov, P. O.; Makkaveev, P. N.; Konovalov, B. V.; Osadchiev, A. A.; Khlebopashev, P. V.; Pelevin, V. V.; Grabovskiy, A. B.; Izhitskiy, A. S.; Goncharenko, I. V.; Soloviev, D. M.; Polukhin, A. A.

    2014-05-01

    This paper presents the results of long-term in situ and satellite measurements at shelf areas adjacent to the estuaries of the small rivers of the Russian coast of the Black Sea (Mezyb, Pshada, Vulan, Tuapse, Bitkha, Sochi, Cudepsta, Mzymta). The quantitative characteristics of the response of the hydrophysical and hydrochemical fields at the sea shelf on the influence of the continental river discharge are presented for each of these areas. A number of indicators of the water quality (the concentrations of the nitrate and nitrite forms of nitrogen, the phosphorus, the silica, the dissolved oxygen, the value of the total alkalinity and pH, the mineral and organic suspended matter, and the chlorophyll a) are considered in the context of the anthropogenic and terrigenous influence. In this paper, the emphasis was placed on the Mzymta River plume at the shelf area adjacent to the city of Sochi, where the measurements were repeatedly performed during the spring flooding conditions in the period from 2007 until 2012. The interannual variability of the water quality indicators and the seasonal and short-term variability of the area and the configuration of the plume, which transports suspended matter and anthropogenic pollution, were considered.

  16. GDGTs of Marine Group II Archaea in the Pearl River Estuary: Toward a Better Understanding of the Bias of TEX86

    Science.gov (United States)

    Zhang, C.; Wang, J. X.; Xie, W.; Chen, S.; Wang, P.

    2014-12-01

    TEX86, calculated based on the distribution of isoprenoid glycerol dialkyl glycerol tetraethers (GDGTs) from planktonic Thaumarchaeota, is widely u