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Sample records for zhangjiang river estuary

  1. Nutrient and caloric dynamics in Avicennia marina leaves at different developmental and decay stages in Zhangjiang River Estuary, China

    Science.gov (United States)

    Zhou, Hai-Chao; Wei, Shu-Dong; Zeng, Qi; Zhang, Li-Hua; Tam, Nora Fung-yee; Lin, Yi-Ming

    2010-03-01

    Avicennia marina is a typical mangrove species in the subtropical coastlines of China. The main objective of this study was to assess nutrient and caloric dynamics in A. marina leaves at different developmental and decay stages. Decomposition studies using litter bags suggested that the time required for the loss of half of the initial dry weight ( t50) was 19 days. The extracts of A. marina leaves contained non-tannin phenolics and tannin phenolics (hydrolysable tannin), but no condensed tannin. Non-tannin phenolics and tannin phenolics contents did not differ significantly from each other at various developmental stages, but decreased rapidly during leaf decomposition. Avicennia marina leaves had high N levels, and both N and P concentrations decreased significantly during senescence. During decomposition, N concentration of the leaf litter increased gradually but the phosphorus concentration showed a decrease in the first week, and both N and P remained the same towards the end of the experiment. The gross caloric value (GCV) of mature leaves was significantly higher than those of young and senescent leaves, while ash-free caloric value (AFCV) did not change significantly during leaf development and senescence. During leaf decomposition, both GCV and AFCV increased gradually and remained the same at late stages. In subtropical Zhangjiang River Estuary, high N levels and lack of condensed tannins in A. marina leaves were responsible for the fast rate of decay. Non-tannin phenolics and tannin phenolics had no great effect on rate of decay. Nitrogen resorption during leaf senescence, and high litter decomposition followed by nitrogen immobilization are the important nutrient conservation strategy for A. marina.

  2. Estuary-wide genetic stock distribution (Columbia River Estuary Tidal Habitats)

    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...

  3. In-stream PIT detection, estuary wetlands (Columbia River Estuary Tidal Habitats)

    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...

  4. Salmon habitat use, tidal-fluvial estuary (Columbia River Estuary Tidal Habitats)

    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)

    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. 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)

  7. 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

  8. Estuaries: Where Rivers Meet the Sea

    Science.gov (United States)

    Take your students on an EstuaryLive telecast! EstuaryLive brings free, live internet field trips in four different estuaries around the country, right to your classroom. These online field trips are the next best thing to an actual trip to an estuary, providing students with an exciting and new way to learn about unique estuarine ecosystems. The site also includes archived webcasts and teacher resources including classroom activities and a glossary.

  9. Rhenium and Molybdenum in Rivers and Estuaries.

    Science.gov (United States)

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

    2004-12-01

    Due to their redox-sensitive nature, the geochemical cycles of Re and Mo are linked to the global organic carbon cycle. Reducing sediments constitute a globally important sink and weathering of organic-rich sediments is responsible for a large portion of the Re and - to a lesser extent - Mo flux to the oceans (Colodner et al., 1993; Jaffe et al., 2002). Riverine concentrations of Re and Mo are a function of the river basin lithology, but are also likely to be affected by anthropogenic contributions (Colodner et al., 1995). Current estimates of global natural riverine Re flux are restricted to single analyses of four major rivers, which characterize only 23%\\ of the global freshwater flux (Colodner et al., 1993). Annual variability of Re and Mo concentrations in rivers has not been studied. A single study of Re concentrations along the salinity gradient of the Amazon shelf is suggestive of conservative mixing, but scatter in the data do not allow to exclude the possibility of Re addition in the low-salinity end of the profile (Colodner et al., 1993). Careful evaluation of samples from the Hudson River estuary using a variety of extraction techniques indicates that spike-sample equilibration was not fully achieved using commonly used methods. We have therefore developed a simple, clean and efficient method of extracting Re from filtered water samples. Our method utilizes syringe filtration, prolonged heating to achieve spike-sample equilibration, batch equilibration with TEVA resin, and extraction of Re and Mo using syringe filtration. Rhenium concentrations in the Hudson, Housatonic and Connecticut rivers are 38 pM, 6.6 pM and 14 pM, respectively, much higher than the estimated global average of 2.1 pM (Colodner et al., 1993). Molybdenum concentrations are 4.6 nM, 5.5 nM, 7.8 nM, respectively. These rivers drain basins of Precambrian basement as well as predominantly Paleozoic sediments and have been substantially urbanized. Data for a salinity profile along the Hudson River estuary are suggestive of conservative mixing of Mo. However, data for Re indicate non-conservative mixing with a significant Re source between 5 and 12 psu. This feature could reflect an anthropogenic point source near Croton Point. Alternatively, it could be caused by a process that transfers Re, but not Mo, from the particulate into the operationally defined dissolved phase. Preliminary data for a Mississippi delta salinity profile suggest projected Re and Mo concentrations of about 90 pM and 26 nM for the freshwater end member, respectively. Our results indicate that the surficial Re cycle is more complex then previously thought. It requires further evaluation before a global estimate of natural riverine Re flux can be accurately constrained. A revision of the marine residence time of Re may be required.

  10. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Dion, E.P.

    1983-01-01

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

  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. Sediment Transport Processes In River Dominated Sub-Tropical Estuaries

    Science.gov (United States)

    DAquino, Carla; Schettini, Carlos

    2014-05-01

    The objective of this study is to present a comparative assessment of the largest three river dominated estuaries in the southern coast of the state of Santa Catarina, Brazil (Tubarão, Araranguá and Mampituba estuaries). The study was focused on mechanisms of transport of suspended sediments influenced by its morphologic and hydrodynamics characteristics. As shown in D'Aquino et al (2011), these estuaries share common attributes (climate and tides) and follow the basic conceptual model of fine sediment transport (presented by Toldo & Schettini (2006). However, each one has its own particularities regarding the geographical setting, land use, hypsometry, outfall, etc. The methodology used to the field measurements was the same for all estuaries, aiming at measuring the currents, water level, salinity, temperature and turbidity near the outfall for at least two complete tidal cycles (~25 hours). All the campaigns were carried on under syzygya tide conditions. During the sample collecting period, a longitudinal profile was conducted in each estuary, through acquisitions of salinity and temperature of the water column in every kilometer. In the Tubarão and Araranguá rivers estuaries, the concentration of suspended particulate matter (SPM) is mostly influenced by the periods of incoming tide, flood currents. In the Mampituba river estuary, the flocculation process was observed during the encounter of fresh and salt water in every tide entrance. It was possible to observe that the Araranguá river estuary, in what concerns the bottom SPM, responds to the variation of salinity and currents along the bottom. The Tubarão estuary presents a relation between the salinity and the bottom currents. In the Mampituba estuary no relevant correlation was found between the SPM, the salinity, and the bottom currents. Those aspects demonstrate that even sharing some characteristics there are significant differences among these estuaries. In addition, as a result of the comparative study, an analytical model was proposed that correlates the fluvial discharge, salt wedge, and SPM. This model might represent a tool to encourage discussions and help the scientific exploration of the estuaries in the south of Santa Catarina.

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

    Digital Repository Service at National Institute of Oceanography (India)

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

    2012-01-01

    river estuary over three years revealed that a decrease in precipitation over the Indian subcontinent from 2007 to 2009 resulted in the lowering of mean annual discharge from 748.63m sup(3) s sup(-1) in 2007 to 218.40 sup(3) s sup(-1) in 2009...

  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. Hydrographic and chemical observations in the Sierra Leone River estuary

    International Nuclear Information System (INIS)

    Hydrographic and chemical observations in the Sierra Leone River estuary are reported, a West-African river in the tropics. Because of the typical change between rainy season in the sommer months and dry season in winter time the research work has been adapted to these semi-annual changes. The collected data and results are given and discussed under this aspect of the seasonal fluctuations. (orig.)

  17. York river destratification: an estuary-subestuary interaction.

    Science.gov (United States)

    Hayward, D; Welch, C S; Haas, L W

    1982-06-25

    Destratification in the York River during high spring tides is the result of the interruption of normal two-layer estuarine flow by the advection of relatively fresh water into the river mouth from the Chesapeake Bay. This advection is due to the presence of a longitudinal salinity gradient in the bay and a difference in the tidal current phase between the river and the bay. Similar behavior is seen in other subestuaries of the Chesapeake Bay and may be common in subestuary-estuary interactions. PMID:17798365

  18. Tracer and model studies of a river and an estuary

    International Nuclear Information System (INIS)

    Radioisotope tracers and mathematical models are used to study transport properties and water quality in the Kymi river and in its estuary in southern Finland. The research area - 200 km2 estuary and 75 km river section - is extensively loaded with industrial and municipal waste waters. Detailed information on dispersion and transport dynamics is gained by four independent tracer studies with 82Br. The results of one study are employed to fix model parameters while the other studies test model validity. In addition to tracer results, direct current recordings and water quality observations are compared with the model results. The river model computes the transport and dispersion of waste releases along the river section. It is used in the analysis of accidental releases which may result in drastic environmental effects. The estuary model computes water flow, transport and dispersion of waste components, as well as water quality distributions under the desired conditions as a function of location and time. Its results now serve as the basis for water quality planning and future management in the area. In general, the combined use of tracer and model techniques seems to be the most adequate approach towards solving the practical prediction problems. The model greatly improves the interpretation and significance of the tracer results while the tracer studies attach the model to reality. (author)

  19. 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 ...

  20. Be isotopes in rivers/estuaries and their oceanic budgets

    International Nuclear Information System (INIS)

    10Be and 9Be have been determined in several North American rivers and in the estuaries of San Francisco Bay and the Pearl River (China). The average fluvial concentration of dissolved 10Be in the rivers is 3220±1960 (1?) atoms/g, almost an order of magnitude higher than the observed estuarine values and slightly higher than the 10Be concentration in the ocean (? 1700 atoms/g). For dissolved 9Be, a similar order-of-magnitude drop in concentration also occurs in going from rivers (750±740 pM) to estuaries (80-140 pM). However, in contrast to the 10Be situation, there appears another order-of-magnitude drop from estuaries to the ocean, which has 9Be concentrations of 5-30 pM. In spite of the wide range of concentrations for both isotopes in river and estuarine waters, 10Be/9Be ratios range mostly from 2 to 12x10-9, with a median value of 7x10-9 (atom/atom), and are much lower than the seawater ratio of ?10-7. In the rivers studied, a given volume of water contains roughly equal amounts of particulate and dissovled 10Be. The 10Be concentration in particulate matter ranges from 2x106 to 1x109 atoms/g-particulate with a median value of about 5x107 atoms/g-particulate. A two-box model calculation shows that coastal regions play an important role in the removal of Be isotopes from thethe removal of Be isotopes from the ocean and that eolian dusts may be the chief source of oceanic 9Be. Because of the marginal removal effect, the overall oceanic residence time of Be should be shorter than the residence time of 500-1200 yr estimated for the open ocean. (orig.)

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

    Science.gov (United States)

    Yu, Yingying; Zhang, Hong; Lemckert, Charles

    2014-11-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Dion, E.P.

    1983-01-01

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

  3. 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 totathe 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

  4. Water and suspended sediment dynamics in Selangor River estuary

    International Nuclear Information System (INIS)

    Observations of salinity, temperature, suspended sediment concentration (SSC) and tidal current velocity were made in the lower and along the longitudinal axis of Sungai Selangor estuary over neap-spring cycles. The variations of these parameters at the measurement stations and along the channel are presented to illustrate the water and sediment dynamics in the estuary. The results shows that the Sungai Selangor estuary changes from a partially-mixed type during neaps to a well-mixed one during springs, promoted by stronger tidal energy during the higher tidal ranges. The strong neap density stratification is also promoted by the high river discharges during the measurement period. Maximum concentration of suspended sediment (> 2000 mg/l) occurs during maximum current velocities both during flood and ebb. The maximum salinity was achieved during high water slack but the salt water was totally flushed out of estuary during low water springs. The longitudinal axis measurement indicates that a partially-developed zone of turbidity maximum with a sediment concentration over 1000 mg/l was observed at the limit of salt water intrusion in salinity range less than 1 ppt. Tidal pumping as oppose to the estuarine circulation is the more dominant factor in the maximum formation as the salt water is totally excluded at low water. (Author)

  5. 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 po 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

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

    Science.gov (United States)

    Liu, Huan; Wu, Jia-xue

    2015-03-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1982-01-01

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

  8. 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

  9. 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.)

  10. 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.

  11. 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.)

  12. 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.

  13. 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

  14. Water quality and health status of the Senegal River estuary.

    Science.gov (United States)

    Troussellier, M; Got, P; Bouvy, M; M'Boup, M; Arfi, R; Lebihan, F; Monfort, P; Corbin, D; Bernard, C

    2004-05-01

    The Senegal River estuary was sampled in May 2002 to get the first data on both the trophic and sanitary status of the water of the main river of the northwest African coast. Several physical, chemical and microbiological variables were measured twice along a transect. Inorganic nutrient concentrations were low while phytoplanktonic abundances (0.58-1.8 x 10(5) cells ml(-1)), bacterial abundances (0.27-8.1 x 10(7) cells ml(-1)), activity (22-474 pmol l(-1) h(-1)), were among the highest recorded in such ecosystems. Microbiological variables revealed a eutrophicated status for this estuary. Largest abundances of fecal contamination bacterial indicators were only detected in localized areas (Saint-Louis city and surrounding areas). The apparent good survival of fecal indicator bacteria in the estuarine waters despite a long residence time (4-5 days) has been evaluated by complementary survival experiments. Exposed to a salinity gradient, a local Escherichia coli strain showed a significantly better survival than those of an E. coli reference strain. PMID:15111032

  15. 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 ...

  16. 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.

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

    Science.gov (United States)

    2011-02-14

    ...contributions to global climate change. The module...floodplain habitats by ocean-type ESUs...structures alter river circulation patterns, sediment...areas in the climate change estuary and...impacts of global climate change is an...

  18. 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.

    2012-01-01

    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...

  19. 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.

    1996-01-01

    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...

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

    Science.gov (United States)

    Pressure and temperature loggers were deployed at 9 sites in the St Louis River estuary between 6/23 10/31 2011. A reference sensor was place on the shore to correct pressure data. Sensors were paced at ...

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

    OpenAIRE

    Fahri; Tamaluddin Syam

    2011-01-01

    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 ...

  2. Changes in Epipelic Diatom Diversity from the Savannah River Estuary

    Directory of Open Access Journals (Sweden)

    Joseph N. Dominy Jr.

    2013-02-01

    Full Text Available Littoral zones can be characterized with temporal exposure of algae to diurnal desiccation at low tides. Combinations of diverse freshwater, marine, and brackish diatoms dominate exposed mud samples. With enlargement of the delta of the Savannah River, Georgia and other anthropogenic influences, changes in the rich epipelic community will not be estimated accurately without baseline data. In the current study, mud samples were taken from the Savannah River estuary along with physicochemical characteristics every two months throughout 2011. Live algal communities were assessed in every sample and live to dead diatom proportions in the communities were calculated. Cleaned diatoms were analyzed following standard protocols. Community indices were compared between sampling events and with literature reports from similar habitats in the Southeastern USA diverse diatom community of 241 species was documented and 39 of those species should be described as new to science. Decrease in species richness and diversity was due to dominance of representatives of the genera Cymatosira and Minidiscus during the summer months.

  3. 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

  4. 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.

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

    Science.gov (United States)

    Ren, Jie; Wu, Jiaxue

    2014-07-01

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

  6. 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.

  7. 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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1985-07-20

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

  9. 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

  10. 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

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

    Science.gov (United States)

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

    2003-01-01

    In the spring of 1998, 24-h time series and synchronization of vertical profiles of NO(3)-N, NO(2)-N, NH(3)-N, PO(4)-P, chlorophyll a, suspended substance, salinity, temperature and other chemical parameters were taken at 10 stations in the Pearl River estuary in order to analyze the status and characteristics of nutrients and eutrophication. The results indicated that dissolved inorganic nitrogen (DIN) mainly came from the four river channels in the main estuary, and NO(3)-N was the main form of DIN in most area. The concentration of DIN was general above 0.30 mg l(-1) in the estuary, and more than 0.50 mgl(-1) in most part. Phosphate from four river channels was not the main sources, but land-based sources from the area near Shenzhen Bay or along the estuary were obvious, and other land-based sources outside the estuary brought by coastal current and flood tide current were also the main contributions. The concentration of phosphate was generally about 0.015 mg l(-1) except the area near Shenzhen Bay. The ratio of N:P was generally high, and it was higher in the north than in the south. The highest ratio was higher than 300, and the lowest one was over 30. The concentration of chlorophyll a was about 0.8-7.8 mg m(-3), and turbidity and phosphate may be the main two limiting factors for algal bloom in the estuary. The concentration of nutrients decreased slightly in the past decade, but still stayed at a high level. The nutrients mainly came from domestic sewage, industrial wastewater, agriculture fertilizer and marine culture in the Pearl River estuary. PMID:12787594

  12. Some physico-chemical aspects of pollution in the Karnafully river estuary

    International Nuclear Information System (INIS)

    An investigation was carried out to determine the characteristics of low tide water of Karnafully river estuary during January to December 1997. The study reveals that low tide water of the estuary is highly turbid which inhibits penetration of incident light (Kt=16.66) and limits the euphotic zone within a narrow depth of 0.19 m. The estuarine water is oligohaline and neutral in nature and remains under-saturated with dissolved oxygen throughout the year. The load of different nutrients is higher than that of the world average of river water. (author)

  13. Aerobic and anaerobic biodegradation of nonylphenol ethoxylates in estuary sediment of Yangtze River, China

    Science.gov (United States)

    Lu, Jian; He, Yiliang; Wu, Jun; Jin, Qiang

    2009-03-01

    The biodegradation behavior of nonylphenol ethoxylates (NPEOs) in estuary sediment of Yangtze River, China, was investigated. NPEOs were readily degraded in the estuary sediment under both aerobic and anaerobic conditions. The highest biodegradation rate constants for the aerobic biodegradation and anaerobic biodegradation were 0.333 and 0.194 day-1, respectively. Anaerobic biodegradation of NPEOs in estuary sediment was enhanced under sulfate-reducing or nitrate-reducing conditions. The biodegradation constants increased by 23.4 and 56.7% in sulfate-adding treatment and nitrate-adding treatment, respectively. NPEOs were biodegraded through the terminal oxidative pathway in estuary sediment under aerobic conditions while these compounds were biodegraded through the non-oxidative pathway under anaerobic conditions. Estrogenic intermediates were formed during NPEO biodegradation under both aerobic and anaerobic conditions. Both treatments reached their highest estrogenicities on day 21. Short-chain nonylphenol ethoxycarboxylates (NPECs), which were feasibly mobile, were only formed under aerobic conditions.

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

    Science.gov (United States)

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

    2014-11-15

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

  15. Late Holocene Geomorphology of the Columbia River Estuary, Oregon and Washington, USA

    Directory of Open Access Journals (Sweden)

    Curt Peterson

    2014-03-01

    Full Text Available Abundant river sediment supply and an open-water central bay area characterize the geomorphology of the large Columbia River estuary (~ 100 km in length. Lateral floodplains and marsh islands do constrict the uppermost reaches of the estuary, but the central axes of the lower estuary are dominated by shallow sand shoals (0–4 m water depth. A total of 58 vibracores are used to document the grain size and age (0–2,500 14CyrBP of late Holocene deposits in the estuary. Sedimentation rates in stable floodplains (1.1 m ka-1 reflect rates of relative sea level rise (0.75 m ka-1. Sedimentation rates of muddy sand accretionary banks and prehistoric sand shoals (1.5–7 m ka-1 greatly exceed coeval rates of sea level rise, so they must represent short–term rates of vertical accretion resulting from channel lateral migration and associated cut and fill processes. The apparent paradox of unfilled accommodation space in the estuary is resolved by 1 winter wind–wave erosion of sand shoals to -3 m NAVD88 elevation and 2 asymmetric fluvial-tidal advection that results in net seaward transport of bed load in shallow tidal channels (> – 10 m NAVD88 and shallow subtidal shoals (> – 4 m NAVD88 during spring river flooding. 

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

    Science.gov (United States)

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

    2013-07-01

    Sampling was conducted monthly during a transition period between the dry and rainy seasons in order to evaluate the effectiveness of a municipal sewage treatment plant (STP) in eutrophication control. STP effluent and fluvial input data were also estimated. In the dry period, high concentrations of nutrients, chlorophyll a (up to 360 ?g?L(-1)), and anoxia in bottom waters were observed in the upper portion of the estuary. Nitrate was scarce during the dry months, although high concentrations were observed at the river sources and the upper estuary. The N:P and Si:P molar ratios were usually below 16:1, and the Si:N ratio was higher than 1:1. The fluvial inputs were a greater source of nutrients to the estuary than the STP, but nutrient loading by these effluents were also important in contributing to the eutrophication of the upper estuarine zone, especially in the dry season when symptoms were more intense. PMID:23179722

  17. Distributions of dissolved titanium in Chesapeake Bay and the Amazon River Estuary

    Science.gov (United States)

    Skrabal, Stephen A.

    1995-06-01

    Total dissolved Ti in Chesapeake Bay and the Amazon River Estuary exists at nanomolar to subnanomolar concentrations. In both estuaries, dissolved Ti is removed at low salinities in the course of estuarine mixing, most likely by coagulation of colloidal metal, perhaps with stabilization of the aggregates by organic material or by adsorption onto other particles. Titanium concentrations in 0.2 ?m-filtered surface samples obtained on a summer survey of Chesapeake Bay range from 0.52-0.87 nM at 0.1 salinity, decreasing to 0.07-0.28 nM at higher salinities. The extent of removal is ?65%. Variable but low levels in the middle estuary probably reflect inputs from tributaries to the bay. A comparison of Ti concentrations in oxic surface waters and suboxic and anoxic bottomwaters shows no consistent evidence for Ti release from dissolving Fe or Mn phases. On a summer survey of the Amazon River Estuary, Ti concentrations in 0.22 ?m-filtered surface waters decrease from 3.3-7.1 nM at salinities of 0.3-0.8 to 0.27-0.62 nM above a salinity of 5, for a removal of > 90%. Slight elevations in Ti concentrations at salinities greater than 34 may result from resuspension of sediments on the dynamic Amazon shelf. Using the Amazon River Estuary as an example, at least 90% of the global flux of dissolved Ti from rivers is removed to particles at low salinities. Considering this, the effective global flux of dissolved Ti from rivers to the oceans, here estimated at ?2 × 10 7 mol y -1, is 10-100 times lower than what has been previously estimated based on river inputs.

  18. 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.

  19. 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...

  20. Geochemistry of Trace Metals from Chinese River/Estuary Systems: An Overview

    Science.gov (United States)

    Zhang, Jing

    1995-12-01

    Based on the data from extensive estuarine studies over 10 years (1983-93), the present work provides an overview of the geochemical features of large Chinese river/estuary systems. Elevated concentrations of major elements are observed in Chinese rivers from north to south, which is attributed to intense weathering and erosion over the drainage basins. Trace metal levels in Chinese rivers are relatively low and similar to those from large and less disturbed world aquatic systems (e.g. Amazon and Orinoco). In the estuaries, particulate elements show stable distributions in the mixing zone especially when absolute concentrations are normalized to aluminium and/or scandium. Dissolved trace metals may have either conservative and/or active (non-conservative) distributions or both in Chinese estuaries. Wherever non-conservative distributions are observed, trace elements may be remobilized and/or scavenged from solution depending upon river discharge, sedimentary dynamics and element. Biological uptake and regeneration of trace metals becomes more important in high salinity areas further offshore the riverine effluent plumes than inside. Correlation of heavy metals with grain size and operational chemical forms reveals a high proportion of elements associated with the fine size fraction compared to total sediments and elevated labile fractions in bottom sediments in anthropogenically disturbed systems. Finally, an estimate is made towards the chemical flux of trace metals to the ocean through Chinese estuaries.

  1. 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.

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

    Science.gov (United States)

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

  3. Nonlinear interaction between the tide and river flow in the Maule estuary, Chile

    Science.gov (United States)

    Arce Morán, D. A.; De La Fuente, A.; Zamorano Riquelme, L.

    2013-12-01

    The hydrodynamics features of an estuary are the resulting of two main driving forces, the tide and the river flow, interacting one each other and with the bathymetry. This periodic modulation may interact with the bathymetry such that exciting new tide harmonics, as a result of the nonlinear effect of bottom friction and advection terms. This nonlinear coupling between the tide and the estuary change when the river flow increases, which explains early theoretical studies that showed that when the river flow increases, there is a shift between M4 and M6 tide harmonic in the estuary. The objective of this study is to analyze field observation where this phenomenon is observed, for which numerical simulations conducted with FVCOM are used for fully understanding this nonlinear interactions between river inflow and tide harmonic excited in an estuary. Field measurements were conducted in June of 2011 in Maule estuary located in central Chile (°35.3S,°72.4W). During this period, the water surface and current were measured along the Thalweg. Also, river flow was continuously recorded at 29km upstream the estuary mouth, and these observations shows a river flow change that rapidly increased in a factor of two, changing the hydrodynamics conditions. Field observations were analyzing based on a least squares analysis, Fourier transforms and continuous wavelet transforms methodologies for processing measured time series. It is obtained that the dominant modes in the estuary are the M4 and M6 tide harmonic. Furthermore, the FVCOM numerical model was implemented to the estuary to study the response of the semi-enclosed system forced by a synthetic time series of the monochromatic M2 tide constituent, to see the excitation of M4 and M6 tide constituents. The results at the mouth of the estuary show that the magnitude of the current induced by the M4 and M6 tide constituents are higher at the bottom after the flood event by a factor of 1.5 and 2.3 respectively, with respect to conditions before the flood. In the contrary, M4 and M6 in the surface decreased because of the flood in a factor of 0.46 and 0.92. Finally, numerical simulation where the estuary was forced with a monochromatic M2 shows similar tendency with the anterior analysis. These results are coherent with the theoretical studies showed that bottom friction shift the magnitude of these harmonics; however, our observations in the surface indicates that the interaction between river flow and the tide depends on the vertical location. 1D numerical models or simple Fourier decomposition of the harmonics in the estuary are not enough to understand the real interaction of the river inflow with the induced current tides. Consequently, vertical variations in the flow velocity are required to be included.

  4. 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)

  5. 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.

    1991-01-01

    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...

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

    Science.gov (United States)

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

    2005-01-01

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

  7. Patterns of Chinook salmon migration and residency in the Salmon River estuary (Oregon)

    Science.gov (United States)

    Bottom, Daniel L.; Jones, Kim K.; Cornwell, Trevan J.; Gray, Ayesha; Simenstad, Charles A.

    2005-07-01

    We examined variations in the juvenile life history of fall-spawning Chinook salmon, Oncorhynchus tshawytscha, for evidence of change in estuarine residency and migration patterns following the removal of dikes from 145 ha of former salt-marsh habitat in the Salmon River estuary (Oregon). Mark-recapture studies and abundance patterns in the estuary during 2000-2002 describe the following life-history types among Chinook salmon: (1) fry disperse throughout the estuary, and many move into restored tidal-marsh habitats in the early spring soon after emergence; (2) juveniles reside in freshwater for several months, enter the estuary in June or July, and remain for (a) a few weeks or (b) several months before entering the ocean; and (3) juveniles enter the ocean later in the fall after an extended period of rearing upriver and/or in the estuary. The absence of fry migrants in the estuary during spring and early summer in 1975-1977 — a period that precedes restoration of any of the diked marshes — and the extensive use of marsh habitats by fry and fingerlings April-July, 2000-2002 indicate that wetland restoration has increased estuarine rearing opportunities for juvenile Chinook salmon. Year-to-year patterns of estuarine rearing and abundance by juvenile salmon may be influenced by flood and drought conditions that affected adult spawner distribution and over-winter survival of salmon eggs. However, persistent changes in spawner distribution since 1975-1977, including the concentration of hatchery strays in the lower river, may account for the large proportion of fry that now disperse into the estuary soon after emergence in the spring. Although few of these earliest migrants survived to the river mouth, many fry and fingerlings from mid- and upper-basin spawning areas distributed throughout a greater portion of the estuary during the spring and summer and migrated to the ocean over a broader range of sizes and time periods than thirty years ago. The results suggest that wetland recovery has expanded life history variation in the Salmon River population by allowing greater expression of estuarine-resident behaviors.

  8. A modeling study on saltwater intrusion to western four watercourses in the Pearl River estuary

    Science.gov (United States)

    Cheng, Xiang-ju; Zhan, Wei; Guo, Zhen-ren; Yuan, Li-rong

    2012-12-01

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

  9. 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.

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

    Science.gov (United States)

    Girjatowicz, Józef Piotr

    2007-09-01

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

  11. Hydrodynamic response of the Breton Sound estuary to pulsed Mississippi River inputs

    Science.gov (United States)

    Huang, Haosheng; Justic, Dubravko; Lane, Robert R.; Day, John W.; Cable, Jaye E.

    2011-11-01

    Pulsed re-introduction of Mississippi River water into the deltaic plain has been proposed as a wetland restoration strategy for coastal Louisiana. In this study, the hydrodynamic response of the Breton Sound estuary to a two-week pulse of Mississippi River water via the Caernarvon river diversion structure was investigated using a barotropic, three-dimensional, Finite-Volume Coastal Ocean Model (FVCOM). The numerical model was driven by tidal and subtidal forcing at the open Gulf boundary, freshwater discharge from the Caernarvon river diversion structure, as well as wind stress at the water surface. After successfully validating the model with field observations, three numerical experiments were run to assess the response of current, water level, and marsh flooding to different diversion discharge scenarios. The three scenarios considered were: a pulsed scenario of ˜200 m 3 s -1 corresponding to the actual diversion discharge in March 2001, a constant discharge scenario of 40 m 3 s -1 corresponding to the annually averaged discharge of 2001, and a scenario with no discharge. Numerical simulation results indicated that constant 40 m 3 s -1 discharge caused little change in wetland inundation comparing to the no discharge case and, thus, inter-exchange between deep channels and the wetlands was not improved by this rate of diversion discharge. In contrast, the two-week ˜200 m 3 s -1 discharge caused enhanced water exchange between wetlands and adjacent water bodies, substantially increasing water velocity in the bayous and channels of the upper estuary. These effects occurred in the estuary to about 20-25 km from the diversion structure, and caused a noticeable increase in down-estuary residual current with a significant reduction of local estuarine residence times for the whole estuary. Beyond 30 km from the diversion structure, the impact of high water discharge was small and the hydrodynamics was mostly controlled by tides and wind.

  12. Numerical simulation of seawater intrusion from estuary into river using a coupled modeling system

    Science.gov (United States)

    Zou, Huazhi; Li, Huajun

    2010-09-01

    One of the most important causes of the freshwater shortage in estuarine area is the increasing seawater intrusion into the river. To simulate seawater intrusion properly, two important factors should be considered. One is the bidirectional and time-dependent coupling effects between river discharges and tidal forces. The other is the three-dimensional and stratified structure of dynamic processes involved. However, these two factors have rarely been investigated simultaneously, or they were often simplified in previous researches, especially for the estuary connected with an upstream river network through multiple outlets such as the Pearl River Estuary (PRE). In order to consider these two factors, a numerical modeling system, which couples a one-dimensional river network model with a three-dimensional unstructured-grid Finite-Volume Coastal Ocean Model (FVCOM), has been developed and successfully applied to the simulation of seawater intrusion into rivers emptying into the PRE. By treating the river network with a one-dimensional model, computational efficiency has been improved. With coupling 1D and 3D models, the specification of upstream boundary conditions becomes more convenient. Simulated results are compared with field measured data. Good agreement indicates that the modeling system may correctly capture the physical processes of seawater intrusion into rivers.

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

    Science.gov (United States)

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

    2006-01-01

    The distributions of dissolved organic carbon (DOC), Ba, U, and a suite of naturally occurring radionuclides in the U/Th decay series (222Rn, 223,224,226,228Ra) were studied during high- and low-discharge conditions in the Loxahatchee River estuary, Florida to examine the role of submarine groundwater discharge in estuarine transport. The fresh water endmember of this still relatively pristine estuary may reflect not only river-borne constituents, but also those advected during active groundwater/surface water (hyporheic) exchange. During both discharge conditions, Ba concentrations indicated slight non-conservative mixing. Such Ba excesses could be attributed either to submarine groundwater discharge or particle desorption processes. Estuarine dissolved organic carbon concentrations were highest at salinities closest to zero. Uranium distributions were lowest in the fresh water sites and mixed mostly conservatively with an increase in salinity. Suspended particulate matter (SPM) concentrations were generally lowest ( 28??dpm L- 1) at the freshwater endmember of the estuary and appear to identify regions of the river most influenced by the discharge of fresh groundwater. Activities of four naturally occurring isotopes of Ra (223,224,226,228Ra) in this estuary and select adjacent shallow groundwater wells yield mean estuarine water-mass transit times of less than 1 day; these values are in close agreement to those calculated by tidal prism and tidal frequency. Submarine groundwater discharge rates to the Loxahatchee River estuary were calculated using a tidal prism approach, an excess 226Ra mass balance, and an electromagnetic seepage meter. Average SGD rates ranged from 1.0 to 3.8 ?? 105??m3 d- 1 (20-74??L m- 2 d- 1), depending on river-discharge stage. Such calculated SGD estimates, which must include both a recirculated as well as fresh water component, are in close agreement with results obtained from a first-order watershed mass balance. Average submarine groundwater discharge rates yield NH4+ and PO4- 3 flux estimates to the Loxahatchee River estuary that range from 62.7 to 1063.1 and 69.2 to 378.5????mol m- 2 d- 1, respectively, depending on river stage. SGD-derived nutrient flux rates are compared to yearly computed riverine total N and total P load estimates. ?? 2006 Elsevier B.V. All rights reserved.

  14. 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.

    2013-01-01

    The geochemistry of the suspended particulate matter (SPM) collected during the monsoon was determined to identify the sources of SPM and to understand the physicochemical processes in the Mandovi and Zuari river estuaries. The concentrations of SPM...

  15. 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

  16. 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.

  17. 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

  18. 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.

  19. 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.

  20. Nitrate sources and dynamics in a salinized river and estuary - a ?15N-NO3- and ?18O-NO3- isotope approach

    Science.gov (United States)

    Xue, D.; Boeckx, P.; Wang, Z.

    2014-10-01

    To trace NO3- sources and assess NO3- dynamics in salinized rivers and estuaries, three rivers (Haihe River: HH River, Chaobaixin River: CB River and Jiyun River: JY River) and two estuaries (HH Estuary and CJ Estuary) along the Bohai Bay (China) have been selected to determine dissolved inorganic nitrogen (DIN: NH4+, NO2- and NO3-. Upstream of the HH River, NO3- was removed 30.9 ± 22.1% by 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. The HH and CY Estuaries behaved mostly conservatively excluding the sewage input in the CJ Estuary. Hydrodynamics in estuaries has been changed by the ongoing reclamation projects, aggravating the loss of the attenuation function of NO3- in the estuary.

  1. 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

  2. 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.

  3. 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

  4. 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)

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

    Science.gov (United States)

    Sholkovitz, Edward R.

    1993-05-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Shokovitz, E.R. (Woods Hole Oceanographic Institution, MA (United States))

    1993-05-01

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

  7. Dispersion of radioactive material discharged to rivers, estuaries and coastal waters

    International Nuclear Information System (INIS)

    The 'dilute and disperse' approach to low level radioactive liquid effluents is presented. The greater the dilution the better the dispersion and the lower the risk to the public. To increase the dilution of the effluent at the discharge point it is usual to discharge through a number of small nozzles and to have as high a discharge velocity as possible. Dispersion is described for rivers, estuaries and the sea. Environmental monitoring of authorised releases of radioactive effluents is also discussed. 2 figs

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

    Science.gov (United States)

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

    2014-06-01

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

  9. 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).

  10. 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.

  11. Predicting water age distribution in the Pearl River Estuary using a three-dimensional model

    Science.gov (United States)

    Ren, Yuheng; Lin, Binliang; Sun, Jian; Pan, Shunqi

    2014-11-01

    The age of water (AW) concept is applied to investigate the water exchange process in a large and density stratified estuary, namely the Pearl River Estuary. A three-dimensional AW model has been built based on an existing hydrodynamic and solute transport model. The model is used to determine the AW distributions inside the Pearl River Estuary under various hydrodynamic conditions. The predicted mean AW values during the dry and wet seasons are approximately 25 and 10 days, respectively. In general, lower AW values are observed in the upper layers near the water surface, while higher values are observed in the lower layers near the bed. The difference becomes more pronounced during the wet season when the river discharge is very large. The tidal influence is relatively small. The variation of tidal forcing impacts mainly on the AW fluctuation range, but it has limited impact on the tidally averaged AW value. Moreover, the AW vertical difference is enhanced during neap tides. A comparison between the predictions using barotropic and baroclinic models indicates that the density-induced circulation has a significant impact on the water exchange rate.

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

    Science.gov (United States)

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

    2014-03-01

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

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. 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 modelinof 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

  18. 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.

  19. The fish community of the Berg River estuary and an assessment of the likely effects of reduced freshwater inflows

    OpenAIRE

    B.A. Bennett

    2012-01-01

    ENGLISH ABSTRACT: Data concerning the species composition, abundance and distribution of fishes in habiting the Berg River estuary are presented and used to assess the value of the estuary to fish, and the likely effects of reduced freshwater in flows. A total of 31 species was recorded, eight of which were classified as estuarine residents, 11 as marine estuarine-opportunist, six as marine stragglers and six were freshwater species. Liza richardsonii, an opportunist, was the most abundant (5...

  20. Evaluation of Genotoxicity of Sediments from the Sado-River Estuary Using Solvent Extractions of Diferent Polarities

    OpenAIRE

    Vicente, Ana Margarida; Sacadura, Joana; Pinto, Miguel; Louro, Henriqueta; Costa, Pedro Manuel; Lavinha, Joa?o; Caeiro, Sandra; Silva, Maria Joa?o

    2013-01-01

    Located in the western coast of Portugal, our case study, the river Sado Estuary, is affected by various sources of pollution, such as heavy-industry, urbanism, mining, agriculture and maritime traffic. Recent studies showed that sediment samples were contaminated with a mixture of different groups of contaminants related to the different anthropogenic pressures along the estuary. The present study aims to assess the cytotoxic and genotoxic potential of these sediments following a fractioning...

  1. 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.

  2. 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)

  3. 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.

    2005-01-01

    for the monsoon months and 7.22 to 8.01 mg m-2 s-1 for the post monsoon months. During pre monsoon period, ammonia is transported towards the river (-0.47 to 0.03 mg m-2 s-1). The net fluxes of nitrite-N are very small and directed upstream during the pre monsoon...

  4. 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.

  5. 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

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

    Science.gov (United States)

    D'Sa, E. J.

    2014-12-01

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

  7. Benthic bacterial biomass and production in the Hudson River estuary

    International Nuclear Information System (INIS)

    Bacterial biomass, production, and turnover were determined for two freshwater march sites and a site in the main river channel along the tidally influenced Hudson River. The incorporation of [methyl-3H]thymidine into DNA was used to estimate the growth rate of surface and anaerobic bacteria. Bacterial production at marsh sites was similar to, and in some cases considerably higher than, production estimates reported for other aquatic wetland and marine sediment habitats. Production averaged 1.8-2.8 mg C·m-2· hour-1 in marsh sediments. Anaerobic bacteria in marsh sediment incorporated significant amounts of [methyl-3H]thymidine into DNA. Despite differences in dominant vegatation and tidal regime, bacterial biomass was similar (1 x 103 ± 0.08 mg C·m-2) in Trapa, Typha, and Nuphar aquatic macrophyte communities. Bacterial abundance and productivity were lower in sandy sediments associated with Scirpus communities along the Hudson River (0.2 x 103 ± 0.05 mg C·m-2 and 0.3 ± 0.23 mg C · m-2· hour-1, respectively)

  8. 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.

  9. Pleistocene macrotidal tide-dominated estuary delta succession, along the Dong Nai River, southern Vietnam

    Science.gov (United States)

    Kitazawa, T.

    2007-01-01

    This paper focuses on the facies and sequence stratigraphic interpretation of a tide-dominated incised-valley system that is rare among geological records of the world for its completeness. The subject is the Middle-Upper Pleistocene Ba Mieu and Thu Duc formations exposed along the Dong Nai River, southern Vietnam. Both the Ba Mieu and the Thu Duc formations are interpreted as a transgressive tide-dominated estuary succession overlain by a highstand tide-dominated delta succession. The tide-dominated estuary succession is generalized as follows, in ascending order: fluvial facies in landward portions, tidal flat, upward-coarsening and -thickening succession of marine sands with a tidal ravinement surface (TRS; created by tidal scouring during transgression) at the base, and subtidal lag in seaward portions. This tide-dominated estuary is distinguished from wave-dominated and wave- and tide-dominated estuaries by (1) the lack of a central basin (lagoon), tidal delta, or bayhead delta facies; (2) the widespread presence of marine sands; (3) the presence of a subtidal lag; and (4) the presence of an upper-flow-regime sand flat facies. The tide-dominated delta succession is generalized as follows, in ascending order: upward-convex unit of marine sand and onlapping tidal flat deposits, a thick upward-fining succession of tidal flat-salt marsh deposits, and coarse fluvial deposits. This delta is distinguished from an estuary as follows. (1) It shows thick, regional, upward-fining successions indicating shallowing, whereas upward-coarsening successions indicating deepening are recognized in an estuary. A maximum flooding surface (MxFS) is recognized in the coarsest part of the succession, in marine sand and tidal flat deposits. (2) Fluvial processes dominate the sediment supply, in contrast to an estuary, in which a thick marine sand body fed from marine sources is dominant. (3) Ebb tidal currents are dominant, whereas flood tidal currents are dominant in an estuary. Key features of the incised-valley system are (1) amplification of the incised-valley geometry by tidal ravinement erosion; (2) development of tidal channels filled with mud clasts in the estuary; (3) a thick marine sand body in the estuary; and (4) upward-convex unit of marine sand and a thick tidal flat-fluvial succession in the delta. The Ba Mieu Formation is recognized as depositional sequence (SQ) 1 between sequence boundary (SB) 1 below and SB2 above. SQ1 consists of transgressive systems tract (TST) 1 and highstand systems tract (HST) 1. SQ1 was formed by a transgression-regression cycle during marine isotope stage (MIS) 7. SB2 was formed by fluvial incision during the MIS 6 lowstand and is amalgamated with the TRS of MIS 5. The Thu Duc Formation is recognized as SQ2 between SB2 below and SB3 above, and it consists of TST2 and HST2. SQ2 was formed by a major transgression-regression cycle on which a lower-rank cyclicity was superposed during MIS 5. TST2 thins seaward as a result of tidal ravinement erosion. The landward extent of marine environment in MIS 5 is inferred to have been of greater scale than that in MIS 7 from the distribution of the facies and the TRS.

  10. Fate of polybrominated diphenyl ethers in the environment of the Pearl River Estuary, South China

    International Nuclear Information System (INIS)

    Ninety-six riverine runoff samples collected at eight major outlets in the Pearl River Delta (PRD), South China, during 2005-2006 were analyzed for 17 brominated diphenyl ether (BDE) congeners (defined as ?17PBDE). Fourteen and 15 congeners were detected, respectively, in the dissolved and particulate phases. These data were further used to elucidate the partitioning behavior of BDE congeners in riverine runoff. Several related fate processes, i.e. air-water exchange, dry and wet deposition, degradation, and sedimentation, within the Pearl River Estuary (PRE), were examined to estimate the inputs of ?10PBDE (sum of the target BDE congeners, BDE-28, -47, -66, -85, -99, -100, -138, -153, -154, and -183) and BDE-209 from the PRD to the coastal ocean based on mass balance considerations. The results showed that annual outflows of ?10PBDE and BDE-209 were estimated at 126 and 940 kg/year, respectively from the PRE to coastal ocean. Besides sedimentation and degradation, the majority of ?10PBDE and BDE-209 discharged into the PRE via riverine runoff was transported to the coastal ocean. - Fate of polybrominated diphenyl ethers in the environment the Pearl River Estuary, South China.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1982-11-01

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

  12. Heavy metals in coastal wetland sediments of the Pearl River Estuary, China

    International Nuclear Information System (INIS)

    Sediment quality in coastal wetlands of the Pearl River Estuary was concerned since the wetlands were used for land reclamation, aquaculture and wildlife protection, and meanwhile served as one of the main ultimate sinks for large amount of heavy metals discharged from the rapidly developing Pearl River Delta. Total concentrations of heavy metal, such as Zn, Ni, Cr, Cu, Pb, and Cd, and their chemical speciation were investigated. Results showed that the sediments were significantly contaminated by Cd, Zn and Ni with concentration ranges of 2.79-4.65, 239.4-345.7 and 24.8-122.1 mg/kg, respectively. A major portion (34.6-46.8%) of Pb, Cd, and Zn was strongly associated with exchangeable fractions, while Cu, Ni and Cr were predominantly associated with organic fractions, residual, and Fe-Mn oxide. Cd and Zn would be the main potential risk and the sediment quality is no longer meeting the demand of the current wetland utilization strategies. - We found that the sediment in coastal wetlands of the Pearl River Estuary was polluted by Cd, Zn and no longer suitable for the current wetland utilization strategies

  13. Heavy metals in coastal wetland sediments of the Pearl River Estuary, China

    Energy Technology Data Exchange (ETDEWEB)

    Li Qusheng [Department of Environmental Engineering, JiNan University, Guangzhou 510632 (China)], E-mail: liqusheng@21cn.com; Wu Zhifeng [Guangdong Institute of Eco-environment and Soil Sciences, Guangzhou 510650 (China); Chu Bei; Zhang Na; Cai Shasha; Fang Jianhong [Department of Environmental Engineering, JiNan University, Guangzhou 510632 (China)

    2007-09-15

    Sediment quality in coastal wetlands of the Pearl River Estuary was concerned since the wetlands were used for land reclamation, aquaculture and wildlife protection, and meanwhile served as one of the main ultimate sinks for large amount of heavy metals discharged from the rapidly developing Pearl River Delta. Total concentrations of heavy metal, such as Zn, Ni, Cr, Cu, Pb, and Cd, and their chemical speciation were investigated. Results showed that the sediments were significantly contaminated by Cd, Zn and Ni with concentration ranges of 2.79-4.65, 239.4-345.7 and 24.8-122.1 mg/kg, respectively. A major portion (34.6-46.8%) of Pb, Cd, and Zn was strongly associated with exchangeable fractions, while Cu, Ni and Cr were predominantly associated with organic fractions, residual, and Fe-Mn oxide. Cd and Zn would be the main potential risk and the sediment quality is no longer meeting the demand of the current wetland utilization strategies. - We found that the sediment in coastal wetlands of the Pearl River Estuary was polluted by Cd, Zn and no longer suitable for the current wetland utilization strategies.

  14. Fate of polybrominated diphenyl ethers in the environment of the Pearl River Estuary, South China

    Energy Technology Data Exchange (ETDEWEB)

    Guan Yufeng [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Graduate School, Chinese Academy of Sciences, Beijing 100049 (China); Sojinu, O.S. Samuel [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Li Shaomeng [Air Quality Research Division, Science and Technology Branch, Environment Canada, 4905 Dufferin Street, Toronto, Ontario M3H 5T4 (Canada); Zeng, Eddy Y., E-mail: eddyzeng@gig.ac.c [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China)

    2009-07-15

    Ninety-six riverine runoff samples collected at eight major outlets in the Pearl River Delta (PRD), South China, during 2005-2006 were analyzed for 17 brominated diphenyl ether (BDE) congeners (defined as SIGMA{sub 17}PBDE). Fourteen and 15 congeners were detected, respectively, in the dissolved and particulate phases. These data were further used to elucidate the partitioning behavior of BDE congeners in riverine runoff. Several related fate processes, i.e. air-water exchange, dry and wet deposition, degradation, and sedimentation, within the Pearl River Estuary (PRE), were examined to estimate the inputs of SIGMA{sub 10}PBDE (sum of the target BDE congeners, BDE-28, -47, -66, -85, -99, -100, -138, -153, -154, and -183) and BDE-209 from the PRD to the coastal ocean based on mass balance considerations. The results showed that annual outflows of SIGMA{sub 10}PBDE and BDE-209 were estimated at 126 and 940 kg/year, respectively from the PRE to coastal ocean. Besides sedimentation and degradation, the majority of SIGMA{sub 10}PBDE and BDE-209 discharged into the PRE via riverine runoff was transported to the coastal ocean. - Fate of polybrominated diphenyl ethers in the environment the Pearl River Estuary, South China.

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

    Science.gov (United States)

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

    2006-12-01

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

  16. 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).

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

    Directory of Open Access Journals (Sweden)

    Joachim Maes

    2012-06-01

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

  18. 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.)

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

    Science.gov (United States)

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

    2010-05-01

    Eutrophication management is still a major challenge in the Baltic Sea region. Estuaries or coastal waters linked to large rivers cannot be managed independently. Nutrient loads into these coastal ecosystems depend on processes, utilisation, structure and management in the river basin. In practise this means that we need a large scale approach and integrated models and tools to analyse, assess and evaluate the effects of nutrient loads on coastal water quality as well as the efficiency of river basin management measures on surface waters and especially lagoons and estuaries. The Odra river basin, the Szczecin Lagoon and its coastal waters cover an area of about 150,000 km² and are an eutrophication hot-spot in the Baltic region. To be able to carry out large scale, spatially integrative analyses, we linked the river basin nutrient flux model MONERIS to the coastal 3D-hydrodynamic and ecosystem model ERGOM. Objectives were a) to analyse the eutrophication history in the river basin and the resulting functional changes in the coastal waters between early 1960's and today and b) to analyse the effects of an optimal nitrogen and phosphorus management scenario in the Oder/Odra river basin on coastal water quality. The models show that an optimal river basin management with reduced nutrient loads (e.g. N-load reduction of 35 %) would have positive effects on coastal water quality and algae biomass. The availability of nutrients, N/P ratios and processes like denitrification and nitrogen-fixation would show spatial and temporal changes. It would have positive consequences for ecosystems functions, like the nutrient retention capacity, as well. However, this optimal scenario is by far not sufficient to ensure a good coastal water quality according to the European Water Framework Directive. A "good" water quality in the river will not be sufficient to ensure a "good" water quality in the coastal waters. Further, nitrogen load reductions bear the risk of increased potentially toxic, blue-green algae blooms. The presentation will summarize recent results (Behrendt et al. 2009, Schernewski et al. 2009, Schernewski et al. in press, Schernewski et al. submitted) and give an overview how Climate Change and socio-economic transformation processes in the river basin will effect coastal water quality during the next decades. The opportunities and threats of a changing lagoon ecosystem for tourism and fisheries, the major economic activities, will be shown.

  20. Multivariate statistical study of heavy metal enrichment in sediments of the Pearl River Estuary

    International Nuclear Information System (INIS)

    Multivariate statistical analysis identified the heavy metal accumulation layers of sediment profiles and showed the various sources of metals in the estuary. - The concentrations and chemical partitioning of heavy metals in the sediment cores of the Pearl River Estuary were studied. Based on Pearson correlation coefficients and principal component analysis results, Al was selected as the concentration normalizer for Pb, while Fe was used as the normalizing element for Co, Cu, Ni and Zn. In each profile, sections with metal concentrations exceeding the upper 95% prediction interval of the linear regression model were regarded as metal enrichment layers. The heavy metal accumulation mainly occurred at sites in the western shallow water areas and east channel, which reflected the hydraulic conditions and influence from riparian anthropogenic activities. Heavy metals in the enrichment sections were evaluated by a sequential extraction method for possible chemical forms in sediments. Since the residual, Fe/Mn oxides and organic/sulfide fractions were dominant geochemical phases in the enriched sections, the bioavailability of heavy metals in sediments was generally low. The 206Pb/207Pb ratios in the metal-enriched sediment sections also revealed the influence of anthropogenic sources. The spatial distribution of cumulative heavy metals in the sediments suggested that the Zn and Cu mainly originated from point sources, while the Pb probably came from sources, while the Pb probably came from non-point sources in the estuary

  1. Multivariate statistical study of heavy metal enrichment in sediments of the Pearl River Estuary

    Energy Technology Data Exchange (ETDEWEB)

    Liu, W.X.; Li, X.D.; Shen, Z.G.; Wang, D.C.; Wai, O.W.H.; Li, Y.S

    2003-03-01

    Multivariate statistical analysis identified the heavy metal accumulation layers of sediment profiles and showed the various sources of metals in the estuary. - The concentrations and chemical partitioning of heavy metals in the sediment cores of the Pearl River Estuary were studied. Based on Pearson correlation coefficients and principal component analysis results, Al was selected as the concentration normalizer for Pb, while Fe was used as the normalizing element for Co, Cu, Ni and Zn. In each profile, sections with metal concentrations exceeding the upper 95% prediction interval of the linear regression model were regarded as metal enrichment layers. The heavy metal accumulation mainly occurred at sites in the western shallow water areas and east channel, which reflected the hydraulic conditions and influence from riparian anthropogenic activities. Heavy metals in the enrichment sections were evaluated by a sequential extraction method for possible chemical forms in sediments. Since the residual, Fe/Mn oxides and organic/sulfide fractions were dominant geochemical phases in the enriched sections, the bioavailability of heavy metals in sediments was generally low. The {sup 206}Pb/{sup 207}Pb ratios in the metal-enriched sediment sections also revealed the influence of anthropogenic sources. The spatial distribution of cumulative heavy metals in the sediments suggested that the Zn and Cu mainly originated from point sources, while the Pb probably came from non-point sources in the estuary.

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

    Science.gov (United States)

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

    2013-08-01

    Roberts Bank, part of the Fraser River delta system on Canada's Pacific coast, is a dynamic estuarine environment supporting important fisheries as well as internationally significant populations of migratory shorebirds. The 8000 ha bank environment comprises a complex of riparian boundaries, intertidal marshes, mud and sand flats, eelgrass meadows, macroalgae and biofilms. Anthropogenic developments (a ferry causeway in 1961 and a port causeway in 1969) have been responsible for changes in tidal flow patterns, tidal elevation, sediment transport and the net expansion of eelgrass beds. The goals of the present study were to (1) directly compare geotechnical properties spanning each side of the coalport causeway, and (2) enhance our understanding of the intercauseway ecosystem under a high-resolution sampling design. Sediment properties (grain size, porosity, organic content, and chlorophyll) and biological communities (eelgrass, macrofauna (0.5-1.0 mm) and meiofauna (0.063-0.5 mm)) were surveyed in 1997 at three stations outside the intercauseway area and three lateral transects spanning the intercauseway tidal flat at tidal heights representing three different habitats: biofilm, Zostera japonica, and Zostera marina. A fine-silt organic-rich porous deposit was observed on the shoreward north side of the coalport causeway relative to the south counterpart, suggesting that consolidation and erosion processes could likely not keep pace with the deposition of Fraser River silt. High chlorophyll levels were found in the protected shoreward northern border of the ferry causeway where fine sands dominate and higher water transparency exists, owing to the redirection of the silt-laden river plume by the coalport causeway. Principle Components Analysis revealed a positive relationship between these porous, organic-rich sediments and cumacean abundance in all regions where eelgrass was absent, including the north side of the coalport causeway. Further, a positive relationship was found between biofilm components (chlorophyll and silt), polydora, and harpacticoid copepod abundance, which, together with cumaceans, are food for Western Sandpipers, Calidris mauri. Finally, 52% of the intercauseway variation was explained by direct correlations between eelgrass attributes and fauna consisting of bivalves, caprellids, and harpacticoid copepods (root biomass, leaf area index), the latter being prey for juvenile salmon which depend on eelgrass beds as rearing habitat. These habitats are vulnerable to changes in tidal flow patterns, tidal elevation, sediment transport, and water clarity that could be caused by future port development and/or sea level rise in response to climate change.

  3. 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.

  4. 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

  5. Spatial distribution and fate of perfluoroalkyl substances in sediments from the Pearl River Estuary, South China.

    Science.gov (United States)

    Gao, Yan; Fu, Jianjie; Meng, Mei; Wang, Yawei; Chen, Baowei; Jiang, Guibin

    2015-07-15

    In this study, 54 sediment samples were collected from the Pearl River Estuary (PRE) in Southern China to study the spatial distribution and patterns of PFASs in this region. PFAS concentrations in the sediment samples ranged from nd (below detection limit) to 2.41ngg(-1)dw (dry weight) with an average value of 0.79ngg(-1)dw. PFAS concentrations were higher at the nearshore sampling sites than in the others. Perfluorobutanesulfonate (PFBS) and perfluorohexanesulfonate (PFHxS) were the two dominant compounds among the target PFASs, which may be due to their production and use as PFOS substitutes in the Pearl River Delta (PRD) areas. Significant linear relationships were found between total PFAS concentrations and total organic carbon (TOC) (R=0.30, p<0.05). The preliminary environmental risk assessment indicated that PFOS and PFOA in the regional sediments posed no significant ecological risk to the benthic organisms at present levels. PMID:26028170

  6. 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

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

    Science.gov (United States)

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

    2007-07-01

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

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

    Science.gov (United States)

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

    2015-04-01

    Nitrate (NO3-) concentrations and the isotopic composition (?15N and ?18O) of water samples from the Pearl River Estuary (PRE), south China, were measured to constrain N sources and processing in springtime. Nitrate concentrations decreased at higher salinities, and dual isotopic values were correlated with 1/[NO3-], both of which suggest mixing of eutrophic freshwater and oligotrophic seawater. However, ?15N and ?18O values did not closely follow the expected mixing lines. At low salinities (0-3.0), some samples exhibited high ?15N and low ?18O values compared with those of the riverine end-member, indicating that sewage is a significant source of nitrate (up to 19.0% calculated from ?15N). At salinities of >3.0, ??15N and ??18O values are linearly correlated with lnƒ (the fraction of NO3- remaining in the system), which is attributable to isotopic Rayleigh fractionation during phytoplankton uptake of nitrate. However, the linear relationship between ??15N and ??18O is different between the west and east PRE, with a slope of 1.18 in the west and 1.59 in the east. This difference most likely resulted from varying degrees of nitrification due to different water velocities and residence times in the two areas. Our data therefore indicate that dual nitrate isotopic signatures are a valuable way to constrain the sources and behavior of nitrate in river-dominated estuaries.

  9. 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).

  10. [Ciliate diversity and spatiotemporal variation in surface sediments of Yangtze River estuary hypoxic zone].

    Science.gov (United States)

    Feng, Zhao; Kui-Dong, Xu; Zhao-Cui, Meng

    2012-12-01

    By using denaturing gradient gel electrophoresis (DGGE) and sequencing as well as Ludox-QPS method, an investigation was made on the ciliate diversity and its spatiotemporal variation in the surface sediments at three sites of Yangtze River estuary hypoxic zone in April and August 2011. The ANOSIM analysis indicated that the ciliate diversity had significant difference among the sites (R = 0.896, P = 0.0001), but less difference among seasons (R = 0.043, P = 0.207). The sequencing of 18S rDNA DGGE bands revealed that the most predominant groups were planktonic Choreotrichia and Oligotrichia. The detection by Ludox-QPS method showed that the species number and abundance of active ciliates were maintained at a higher level, and increased by 2-5 times in summer, as compared with those in spring. Both the Ludox-QPS method and the DGGE technique detected that the ciliate diversity at the three sites had the similar variation trend, and the Ludox-QPS method detected that there was a significant variation in the ciliate species number and abundance between different seasons. The species number detected by Ludox-QPS method was higher than that detected by DGGE bands. Our study indicated that the ciliates in Yangtze River estuary hypoxic zone had higher diversity and abundance, with the potential to supply food for the polyps of jellyfish. PMID:23479889

  11. Polycyclic aromatic hydrocarbons in suspended particulate matter and sediments from the Pearl River Estuary and adjacent coastal areas, China

    International Nuclear Information System (INIS)

    The spatial distribution, composition, and sources of polycyclic aromatic hydrocarbons (PAHs) in sediments and suspended particulate matter (SPM) from the Pearl River Estuary and adjacent coastal areas were examined. Total PAH concentrations varied from 189 to 637 ng/g in sediments and 422 to 1850 ng/g in SPM. PAHs were dominated by 5,6-ring compounds in sediments and by 2,3-ring compounds in SPM samples. Assessment of PAH sources suggested that biomass and coal combustion is the major PAH source to the outer part of the estuary sediments and that petroleum combustion is the major PAH source to the inner part of estuary sediments. As for SPM samples, PAH isomer pair ratios indicated multiple (petroleum, petroleum combustion, and biomass and coal combustion) PAH sources, and significant temporal variations could exist for the sources of water column PAHs in the study area. The distribution of perylene in SPM samples indicated that the river was the dominant source of perylene in SPM and that perylene could be taken as an index to assess the contribution of river inflow to the total PAHs in SPM samples. The high concentration of perylene in the sediment was indicative of an in situ biogenic origin. - PAH were determined in suspended particulate matter and sediments from Pearl River Estuary

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

    Science.gov (United States)

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

  13. Polycyclic aromatic hydrocarbons in suspended particulate matter and sediments from the Pearl River Estuary and adjacent coastal areas, China

    Energy Technology Data Exchange (ETDEWEB)

    Luo Xiaojun [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, P.O. Box 1131, Guangzhou 510640 (China); Chen Shejun [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, P.O. Box 1131, Guangzhou 510640 (China); Mai Bixian [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, P.O. Box 1131, Guangzhou 510640 (China)]. E-mail: nancymai@gig.ac.cn; Yang Qingshu [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, P.O. Box 1131, Guangzhou 510640 (China); Institute of Estuarine and Coastal Research, Zhongshan University, Guangzhou 510275 (China); Sheng Guoying [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, P.O. Box 1131, Guangzhou 510640 (China); Fu Jiamo [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, P.O. Box 1131, Guangzhou 510640 (China)

    2006-01-15

    The spatial distribution, composition, and sources of polycyclic aromatic hydrocarbons (PAHs) in sediments and suspended particulate matter (SPM) from the Pearl River Estuary and adjacent coastal areas were examined. Total PAH concentrations varied from 189 to 637 ng/g in sediments and 422 to 1850 ng/g in SPM. PAHs were dominated by 5,6-ring compounds in sediments and by 2,3-ring compounds in SPM samples. Assessment of PAH sources suggested that biomass and coal combustion is the major PAH source to the outer part of the estuary sediments and that petroleum combustion is the major PAH source to the inner part of estuary sediments. As for SPM samples, PAH isomer pair ratios indicated multiple (petroleum, petroleum combustion, and biomass and coal combustion) PAH sources, and significant temporal variations could exist for the sources of water column PAHs in the study area. The distribution of perylene in SPM samples indicated that the river was the dominant source of perylene in SPM and that perylene could be taken as an index to assess the contribution of river inflow to the total PAHs in SPM samples. The high concentration of perylene in the sediment was indicative of an in situ biogenic origin. - PAH were determined in suspended particulate matter and sediments from Pearl River Estuary.

  14. 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

  15. 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 (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.

  16. Effects of Three Gorges Reservoir (TGR water storage in June 2003 on Yangtze River sediment entering the estuary

    Directory of Open Access Journals (Sweden)

    Z. X. Chu

    2006-07-01

    Full Text Available The world-greatest water conservancy project, Three Gorges Reservoir (TGR, stored water for the first time in June 2003, which provides an excellent opportunity to examine its effects on the sediment entering the Yangtze River estuary. A daily record dataset of water discharge and suspended sediment concentration (SSC of the Yangtze River measured at Datong (the controlling hydrological gauging station into the estuary from May 15 to July of 2003 spanning the water storage, together with a monthly record dataset of runoff, sediment load and SSC measured at Datong from 1953 to 2003, were used to examine the effects of the TGR water storage in June 2003 on the Yangtze River sediment entering the estuary. The results show that the unnaturally clearer water due to the TGR sedimentation resulted by the water storage in June 2003 brought the Yangtze River markedly decreased SSC and sediment load entering the estuary both during the TGR water storage and in the second half year of 2003.

    The Yangtze River water and sediment discharges into the estuary from 15 May to 15 July in 2003 spanning the TGR water storage clearly indicated three phases: (1 pre-water storage of the TGR from 15 May to 25 May, during this phase, SSC and sediment load increased with water discharge increasing; (2 water storage of the TGR from 25 May to 10 June (including the preparation phase from 25 May to 31 May, during this phase, SSC and sediment load decreased dramatically with water discharge decreasing; and (3 post-water storage of the TGR, at the beginning, SSC, sediment load and water discharge basically remained at a relatively low value until the end of June, and since then, SSC and sediment load increased gradually with water discharge increasing. In addition, the real total sediment load was reduced by 2456.07×104 t than the estimated total sediment load during the period from 27 May to 2 July in 2003.

  17. 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.

  18. 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

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

    Science.gov (United States)

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

    2013-05-01

    The geochemistry of the suspended particulate matter (SPM) collected during the monsoon was determined to identify the sources of SPM and to understand the physicochemical processes in the Mandovi and Zuari river estuaries. The concentrations of SPM decrease seaward in both estuaries, but are relatively high at bay stations. Kaolinite is the most dominant clay mineral in the upstream of both rivers. Smectite increases seaward in both estuaries and is abundant in the bay. Upstream stations of Mandovi, where ore deposits are stored on the shore, exhibit high Fe, Mn, total rare earth elements (?REE), and middle REE- and heavy REE-enriched patterns. Channel stations of both estuaries exhibit middle REE- and light REE-enriched patterns, which gradually changed seaward to middle REE- and heavy REE-enriched patterns. Canal stations exhibit the highest concentrations of major and trace metals. High metal/Al ratios occur at stations in the upstream of Zuari and at the confluence of canals in the Mandovi estuary. Enrichment factors of metals indicate that Mn is significantly polluted while other metals are moderately polluted. The ?(13)C and ?(15)N of organic matter indicate that the terrigenous organic matter at the upstream is diluted seaward by marine organic matter. Organic matter at bay stations is largely marine and altered-type. The compositions of SPM are controlled by the particulates from ore dust, the geology of the drainage basins, and the physicochemical processes in the estuaries. Particulates resuspended from the bay are dominated by ore dust, which are advected into the channels of both estuaries during the lull periods of the monsoon. PMID:23054263

  20. 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.

  1. 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 ac 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.

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

    Science.gov (United States)

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

    2015-01-01

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

  3. 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.

  4. 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.

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

    Science.gov (United States)

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

    2011-12-01

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

  6. 239 240Pu and 238Pu in sediments of the Hudson River estuary

    International Nuclear Information System (INIS)

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

  7. 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.

  8. 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)

  9. 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.

  10. 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.

    2139-21-01

    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.

  11. 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.

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

    Science.gov (United States)

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

    2003-11-01

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

  13. Hydrographic Study of a Highly Stratified River Mouth Estuary. Alvarado Coastal Lagoon, México

    Science.gov (United States)

    Perales-Valdivia, H.; Sanay, R.

    2014-12-01

    Two 24 hours surveys on high and low river discharge conditions were used to describe the hydrography and the currents at the entrance of Alvarado Coastal Lagoon, México, located at the southwestern coast of the Gulf of México. This study represent the first of this kind in this lagoon. The Alvardo Coastal Lagoon sustains several economical fisheres in the region, including the shrimp fishery. The inlet of the Alvarado Coastal Lagoon is a microtidal rivermouth estuary. In each survey, towed ADCP and hydrographic data were sampled during a diurnal tidal cycle for three across-inlet transects located near the mouth. 12 track repetitions were completed allowing to distinguish the subtidal and tidal signals. In both runoff conditions a salt wedge was present, and showed surface-bottom salinity difference up to 35 psu. During high river discharge condition the salt wedge was present only during flood tide. The thicknesses of the interface, and upper and bottom layers oscillated according the tide. The water surface layer was always toward the ocean. During low river discharge condition the salt wedge was present for the whole tidal cycle. The vertical position of the interface oscillated as the tide did but keeping a constant thickness.

  14. Estimates of entrainment mortality for striped bass and other fish species inhabiting the Hudson River estuary

    International Nuclear Information System (INIS)

    An empirically derived age-, time-, and space-variant equation was used to estimate entrainment mortality at power plants for seven fish species inhabiting the Hudson River estuary. Entrainment mortality is expressed as a conditional rate, which is the fractional reduction in year-class strength due to entrainment if other sources of mortality are density-independent. Estimates of the conditional entrainment mortality, based on historical and projected once-through cooling operation of five power plants, were 11-22% for striped bass, 11-17% for white perch, 5-7% for Atlantic tomcod, 14-21% for American shad, 4-11% for river herring (alewife and blueback herring combined), and 35-79% for bay anchovy. Closed-cycle cooling (natural-draft cooling towers) at three of the power plants (Indian Point, Bowline Point, and Roseton) would reduce entrainment mortality of striped bass by 50-80%, of white perch by 75-80%, of Atlantic tocod by 65-70%, of American shad by 80%, of river herring by 30-90%, and of bay anchovy by 45-80%. The life stages most vulnerable to entrainment mortality were post-yolk-sac larva and entrainable size juvenile. 18 refs., 7 tabs

  15. [Spatial variations of biogenic elements in coastal wetland sediments of the Jiulong River Estuary].

    Science.gov (United States)

    Yu, Xiao-Qing; Yang, Jun; Liu, Le-Mian; Tian, Yuan; Yu, Zheng; Wang, Chang-Fu

    2012-11-01

    To reveal the spatial distribution of biogenic elements and their influencing factors in the typical subtropical coastal wetland, both surface and core sediment samples were collected from the Jiulong River Estuary, southeast China in summer 2009. The biogenic elements including carbon, nitrogen, phosphorus, sulfur (C, N, P, S) were determined by Element Analyzer and Flow Injection Analyzer. The concentrations of TC, TN, TP, and TS were (12.64 +/- 2.66) g x kg(-1), (1.57 +/- 0.29) g x kg(-1), (0.48 +/- 0.06) g x kg(-1), and (2.61 +/- 1.37) g x kg(-1), respectively. Further, these biogenic elements showed a distinct spatial pattern which closely related with the vegetation type and tide level. Values of TC, TN, TP in the surface sediment of mangrove vegetation zones were higher than those in the cord-grass and mudflat zones, while TC, TN, TP concentrations in the high tide level regions were higher than those in the middle and low tide level regions. The TS concentration was the highest in cord-grass vegetation and middle tidal level zones. The TC and TN values in sedimentary core decreased gradually with depth, and they were the highest in the mangrove sites, followed by cord-grass and mudflat sites at the same depth. In mudflat sedimentary core, the average content of TP was the lowest, whereas TS was the highest. Redundancy analysis revealed that vegetation type, pH and tide level were the main factors influencing the distribution of biogenic elements in surface sediments of the Jiulong River Estuary, by explaining 24.0%, 19.0% and 11.6% of total variation in the four biogenic elements (C, N, P and S), respectively. PMID:23323401

  16. Holocene Sedimentation in the Ångermanälven River Estuary, the northern Baltic Sea

    Science.gov (United States)

    Kotilainen, Aarno; Hyttinen, Outi; Obrochta, Stephen; Andrén, Thomas; Ryabchuk, Daria; Snowball, Ian; IODP Expedition 347 Science Party, The

    2015-04-01

    In the IODP Expedition 347 - "Baltic Sea Paleoenvironment" - two sites in the Ångermanälven River estuary were drilled. Sites M0061 and M0062 are located at about 62°47'N, in an area which was deglaciated ca. 10 ka ago. It has long been known that varve deposition is an ongoing process in Ångermanälven estuary, and that it has continued so several thousand years back in time. It has also been shown that a correlation exists between maximum daily discharge and mean varve thickness at least AD 1901-1971 in the Ångermanälven River (Sander et al. 2002). Studying varve thickness and sediment geochemistry potentially yield estimations on past changes in precipitation and sedimentation processes in the estuary. In this presentation, the preliminary results from site M0062 are shown. The core recovery was approximately 36 m and the sediment sequence was divided into two lithological units (Expedition 347 Scientists, 2014). The lowest Unit 2 (17.09-35.9 mbsf) consists of well-sorted sand, deposited by a (glacio)fluvial system. Unit 1 (0-17.09 mbsf) showed transition from glacial lake varves to brackish marine couplets. The uppermost 18 metres were analysed for grain-size and elemental geochemistry every 0.3-0.5 m. From selected intervals, a 1mm-resolution XRF-scanning of the split core surface was done to compare changes in the relative abundance of light elements. Results from Ångermanälven were compared with measurements from glacial varved sediments, retrieved from the eastern Gulf of Finland. This work is also part of "Climate - ice sheet - sea interactions - evolution of the Baltic Sea Basin over the past 60000 years (CISU)" which is a new joint research project with The Academy of Finland and The Russian Foundation for Basic Research. The CISU project is coordinated by Geological Survey of Finland and the other partners are Helsinki University and A.P. Karpinsky Russian Geological Research Institute (VSEGEI), Russia. The project bases on the IODP Expedition 347 material and new sediment core material from the eastern Gulf of Finland. Expedition 347 Scientists, 2014. Baltic Sea Basin Paleoenvironment: paleoenvironmental evolution of the Baltic Sea Basin through the last glacial cycle. IODP Prel. Rept., 347. 102 pages. doi:10.2204/iodp.pr.347.2014. http://publications.iodp.org/preliminary_report/347/ Sander, M., Bengtsson, L., Holmquist, B., Wohlfarth, B., and Cato, I., 2002. The relationship between annual varve thickness and maximum annual discharge (1909-1971). J. Hydrol., 263(1-4):23-35. doi:10.1016/S0022-1694(02)00030-6.

  17. SOURCES AND TRANSFORMATIONS OF NITROGEN, CARBON, AND PHOSPHORUS IN THE POTOMAC RIVER ESTUARY

    Science.gov (United States)

    Pennino, M. J.; Kaushal, S.

    2009-12-01

    Global transport of nitrogen (N), carbon (C), and phosphorus (P) in river ecosystems has been dramatically altered due to urbanization. We examined the capacity of a major tributary of the Chesapeake Bay, the Potomac River, to transform carbon, nitrogen, and phosphorus inputs from the world’s largest advanced wastewater treatment facility (Washington D.C. Water and Sewer Authority). Surface water and effluent samples were collected along longitudinal transects of the Potomac River seasonally and compared to long-term interannual records of carbon, nitrogen, and phosphorus. Water samples from seasonal longitudinal transects were analyzed for dissolved organic and inorganic nitrogen and phosphorus, total organic carbon, and particulate carbon, nitrogen, and phosphorus. The source and quality of organic matter was characterized using fluorescence spectroscopy, excitation emission matrices (EEMs), and PARAFAC modeling. Sources of nitrate were tracked using stable isotopes of nitrogen and oxygen. Along the river network stoichiometric ratios of C, N, and P were determined across sites and related to changes in flow conditions. Land use data and historical water chemistry data were also compared to assess the relative importance of non-point sources from land-use change versus point-sources of carbon, nitrogen, and phosphorus. Preliminary data from EEMs suggested that more humic-like organic matter was important above the wastewater treatment plant, but more protein-like organic matter was present below the treatment plant. Levels of nitrate and ammonia showed increases within the vicinity of the wastewater treatment outfall, but decreased rapidly downstream, potentially indicating nutrient uptake and/or denitrification. Phosphate levels decreased gradually along the river with a small increase near the wastewater treatment plant and a larger increase and decrease further downstream near the high salinity zone. Total organic carbon levels show a small decrease downstream. Ecological stoichiometric ratios along the river indicate increases in C/N ratios downstream, but no corresponding trend with C/P ratios. The N/P ratios increased directly below the treatment plant and then decreased gradually downstream. The C/N/P ratios remained level until the last two sampling stations within 20 miles of the Chesapeake Bay, where there is a large increase. Despite large inputs, there may be large variations in sources and ecological stoichiometry along rivers and estuaries, and knowledge of these transformations will be important in predicting changes in the amounts, forms, and stoichiometry of nutrient loads to coastal waters.

  18. 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.

  19. 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.

  20. Analysis of HCHs and DDTs in a sediment core from the Old Yellow River Estuary, China.

    Science.gov (United States)

    Da, Chunnian; Liu, Guijian; Yuan, Zijiao

    2014-02-01

    The present study analyzed the distribution of HCHs and DDTs in a sediment core from the Old Yellow River Estuary, China. The OCP levels were detected by Soxhlet extraction followed by gas chromatography (GC) using a mass-selective detector. Sediment age was analyzed for (210)Pb using an Ortec GWL HPGe gamma spectrometer. The results indicated that the concentrations of ?DDT in the sediment core were much lower than those of ?HCH. Compared with the other estuarine and coastal regions in Chinese rivers, HCHs levels in this area were higher or similar, while DDTs levels were lower. The compositional analysis indicated that ?-HCH and p, p'-DDD were the predominant species. The temporal trends indicated that levels of HCHs and DDTs were related with their historical usage, emission and soil residues. According to the analysis of the ratio, HCHs in this area was mainly due to the technical historical residue and recent lindane. DDTs was mainly due to historical residue. The biodegradation conditions for DDTs were anaerobic. The dicofol-type DDTs application occurred in this area. PMID:24268742

  1. 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).

  2. 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.

  3. 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.

    2011-01-01

    ). Air-water flux of CO 2 was estimated following Wanninkhof (1992) using measured wind speed. 3. Results and discussion The dam controlled freshwater discharge into the Godavari estuary was maximal in August (Fig. 2a). There was virtually... for the polluted estuaries such as the Rhine (~25000 ?atm; Kempe, 1982) and the Scheldt estuaries (~15200 ?atm; Borges and Frankignoulle, 2002) are far below the levels found in the Godavari estuary. In most other estuaries, pCO 2 was <10,000 ?atm (Table 2...

  4. 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.

  5. 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.

  6. Influence of bathymetry evolution on position of tidal shear front and hydrodynamic characteristics around the Yellow River estuary

    Science.gov (United States)

    Lu, Yucen; Shen, Yongming

    2012-12-01

    A three dimensional numerical model based on the hydrodynamic module of finite-volume coastal ocean (FVCOM) was established for the Yellow River estuary. The model has been calibrated by observed data and proved to be suitable to reflect the hydrodynamic force in the research area. We employed the model to simulate the tidal shear front off the Yellow River estuary and analyzed the formation, spread and duration of two different types of shear front. To examine the effect of bathymetry evolution on the position of tidal shear front, subaqueous bathymetry of the Yellow River estuary was changed according to the changing patterns obtained from the past few years. Tidal shear front was modeled on both the original and the changed bathymetry. The results show that the position of shear front moved from a shallow to a deep area due to the deposition of bathymetry. The influence of bathymetry evolution on hydrodynamic characteristics including the distribution of salinity and the movement of particles was studied. We found the dispersion areas of low salinity became larger after changing bathymetry and the particles on the surface, middle and bottom layer are able to move further both north and west of Laizhou Bay on the changed bathymetry.

  7. Polycyclic aromatic hydrocarbons in suspended particulate matter and sediments from the Pearl River Estuary and adjacent coastal areas, China

    Energy Technology Data Exchange (ETDEWEB)

    Luo, X.J.; Chen, S.J.; Mai, B.X.; Yang, Q.S.; Sheng, G.Y.; Fu, J.M. [Chinese Academy of Sciences, Ghangzhou (China)

    2006-01-01

    The spatial distribution, composition, and sources of polycyclic aromatic hydrocarbons (PAHs) in sediments and suspended particulate matter (SPM) from the Pearl River Estuary and adjacent coastal areas were examined. Total PAH concentrations varied from 189 to 637 ng/g in sediments and 422 to 1850 ng/g in SPM. PAHs were dominated by 5, 6-ring compounds in sediments and by 2,3-ring compounds in SPM samples. Assessment of PAH sources suggested that biomass and coal combustion is the major PAH source to the outer part of the estuary sediments and that petroleum combustion is the major PAH source to the inner part of estuary sediments. As for SPM samples, PAH isomer pair ratios indicated multiple (petroleum, petroleum combustion, and biomass and coal combustion) PAH sources, and significant temporal variations could exist for the sources of water column PAHs in the study area. The distribution of perylene in SPM samples indicated that the river was the dominant source of perylene in SPM and that perylene could be taken as an index to assess the contribution of river inflow to the total PAHs in SPM samples. The high concentration of perylene in the sediment was indicative of an in situ biogenic origin.

  8. 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

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

    Science.gov (United States)

    Wallin, Jaana; Karjalainen, Anna K; Schultz, Eija; Järvistö, Johanna; Leppänen, Matti; Vuori, Kari-Matti

    2015-03-01

    Acidity and leaching of metals from acid sulphate soils (ASSs) impair the water quality of receiving surface waters. The largest ASS areas in Europe are found in the coasts of the northern Baltic Sea. We used weight-of-evidence (WoE) approach to assess potential risks in 14 estuary sites affected by ASS in the Gulf of Finland, northern Baltic Sea. The assessment was based on exposure and effect profiles utilizing sediment and water metal concentrations and concurrent pH variation, sediment toxicity tests using the luminescent bacterium Vibrio fischeri and the midge Chironomus riparius, and the ecological status of benthic macroinvertebrate communities. Sediment metal concentrations were compared to national sediment quality criteria/guidelines, and water metal concentrations to environmental quality standards (EQSs). Hazard quotients (HQs) were established for maximum aluminium, cadmium and zinc concentrations at low pH based on applicable US EPA toxicity database. Sediment metal concentrations were clearly elevated in most of the studied estuaries. The EQS of cadmium (0.1 ?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. PMID:25506908

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

    Science.gov (United States)

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

    2012-06-01

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

  11. 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.

    2005-01-01

    between polluted and non-polluted areas. Marine Micropalaeontology, 45, 151–168. HAIG, D.W. and BURGIN, S., 1982. Brackish water foraminiferids from the Purari River Delta, Papua New Guinea. Revista Espanola de Micropaleontologia, 14, 359–366. HASHIMI, N...), with Special Reference to Mining Pollution. Goa, India: Goa Uni- versity, M.Sc. thesis, 105p. NAYAK, G.N., 1993. Studies on Sediment Flux of Rivers, Estuaries and Adjoining Coastal Waters of Goa, West Coast of India. Tech- nical report submitted to Department...

  12. [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

  13. On the role of wind and tide in generating variability of Pearl River plume during summer in a coupled wide estuary and shelf system

    Science.gov (United States)

    Zu, Tingting; Wang, Dongxiao; Gan, Jianping; Guan, Weibing

    2014-08-01

    A numerical simulation of the buoyant river plume over the Pearl River Estuary (PRE) and adjacent shelf during a typical upwelling favorable wind period of the summer monsoon is utilized to explore the responses of the plume to wind and tide forcing. The model is forced with time-dependent river discharge, wind and tide, and it shows reasonable ability to capture the basic structure and responses of the plume. Additional numerical experiments that are forced without either wind or tide are used to evaluate the relative importance of wind and tide in generating plume variability. Results show that the vertical structure of the plume and the strength of the stratification in the estuary are determined by the combination of the buoyancy forcing associated with river discharge and tidal forcing, and vary with the advection process, while the horizontal shape and spreading of the plume over the shelf are highly influenced by the wind-driven coastal current, and are more susceptible to the change of vertical mixing. Mechanical energy analysis in each dynamical region (upper, middle, lower estuary, and shelf) reveals that this is because the system mainly gains energy from tide (wind) in the estuary (shelf), and loses energy to the bottom friction (internal-shear mixing) in the estuary (shelf). The largest forcing and dissipation terms in the middle PRE, and at the entrances of smaller estuaries such as Huang Mao Hai, are due to tidal forcing, which enables the middle PRE to serve dynamically as the entrance of an estuary, where the transition of the river plume into coastal buoyancy current usually takes place. In addition, the mixing efficiency increases from upper PRE to the shelf and from strong to weak mixing period, thus the plume in the well-mixed upper estuary is not as sensitive to the changes of wind and tide as that over the highly stratified shelf.

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

    Science.gov (United States)

    Nehring, Stefan

    2006-05-01

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

  15. 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 ?g/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 mpact of stressors on coastal ecosystem health

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

    Science.gov (United States)

    Cheng, Fangping; Wang, Minxiao; Li, Chaolun; Sun, Song

    2014-07-01

    DNA barcoding provides accurate identification of zooplankton species through all life stages. Single-gene-targeted metagenomic analysis based on DNA barcode databases can facilitate longterm monitoring of zooplankton communities. With the help of the available zooplankton databases, the zooplankton community of the Changjiang (Yangtze) River estuary was studied using a single-gene-targeted metagenomic method to estimate the species richness of this community. A total of 856 mitochondrial cytochrome oxidase subunit 1 (cox1) gene sequences were determined. The environmental barcodes were clustered into 70 molecular operational taxonomic units (MOTUs). Forty-two MOTUs matched barcoded marine organisms with more than 90% similarity and were assigned to either the species (similarity>96%) or genus level (similarity<96%). Sibling species could also be distinguished. Many species that were overlooked by morphological methods were identified by molecular methods, especially gelatinous zooplankton and merozooplankton that were likely sampled at different life history phases. Zooplankton community structures differed significantly among all of the samples. The MOTU spatial distributions were influenced by the ecological habits of the corresponding species. In conclusion, single-gene-targeted metagenomic analysis is a useful tool for zooplankton studies, with which specimens from all life history stages can be identified quickly and effectively with a comprehensive database.

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

    Science.gov (United States)

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

    2014-06-01

    Current research has seldom focused on the quantitative relationships between Vibrio cholerae (V. cholerae) and climate factors owing to the complexities and high cost of field observation in the aquatic environment. This study has focused on the relationships between V. cholerae and climate factors based on linear regression method and data partition method. Data gathered from 2008 to 2009 in the Pearl River estuary, South China, were adopted. Positive rate of V. cholerae was correlated closely with monthly climate factors of water temperature and air temperature, respectively in 2009. Quarterly data analysis from 2008 to 2009 showed that there existed seasonal characteristic for V. cholerae. Positive rate of V. cholerae was correlated positively with quarterly climate factors of land surface temperature, pH, water temperature, air temperature and rainfall, respectively and negatively with quarterly air pressure. Partition data analysis in 2009 showed that there existed geography region characteristic for V. cholerae. V. cholerae dynamics was closely correlated to climate factors in the downstream area. However, it was more greatly affected by human geography factors in the urban area. Positive annual rate of V. cholerae was higher in the downstream area than in the urban area both in 2008 and 2009. At last, a cellular automaton model was used to simulate V. cholerae diffusion downstream, and the distribution of V. cholerae obtained from this model was similar to that obtained from the field observations. PMID:24442820

  18. 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

  19. Beryllium-7 atmospheric deposition and sediment inventories in the Neponset River estuary, Massachusetts, USA

    International Nuclear Information System (INIS)

    Measured monthly atmospheric depositional fluxes of cosmogenically produced 7Be ranged from 1 to 67 mBq/cm2 in Boston, Massachusetts between September 2000 and August 2007. These fluxes exhibited seasonality and supported a decay-corrected 7Be atmospheric depositional running inventory that ranged from 36 to 144 mBq/cm2. Annual 7Be deposition exhibited an increasing trend that may reflect a general decrease in solar activity and a general increase in precipitation over the 7-year sampling period. To investigate short-term sediment dynamics and accumulation patterns in the Neponset River estuary, we collected six sediment cores in July 2006 and measured 7Be sediment inventories ranging from 48 to 546 mBq/cm2 Comparisons of these sediment inventories with the 7Be running inventory from atmospheric deposition (101 mBq/cm2) at the time of core collection indicated a large degree of spatial heterogeneity in sediment accumulation patterns and its potential use as a tool for assessing the impacts of environmental restoration activities in estuarine environments

  20. 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.

  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. 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

  3. Over one hundred years of trace metal fluxes in the sediments of the Pearl River Estuary, South China

    International Nuclear Information System (INIS)

    The rapid economic development in the Pearl River Delta (PRD) region in South China in the last three decades has had a significant impact on the local environment. Estuarine sediment is a major sink for contaminants and nutrients in the surrounding ecosystem. The accumulation of trace metals in sediments may cause serious environmental problems in the aquatic system. Thirty sediment cores were collected in the Pearl River Estuary (PRE) in 2000 for a study on trace metal pollution in this region. Heavy metal concentrations and Pb isotopic compositions in the four 210Pb-dated sediment cores were determined to assess the fluxes in metal deposits over the last one hundred years. The concentrations of Cu, Pb and Zn in the surface sediment layers were generally elevated when compared with the sub-surface layers. There has been a significant increase in inputs of Cu, Pb and Zn in the PRE since the 1970s. The results also showed that different sampling locations in the estuary received slightly different types of inputs. Pb isotopic composition data indicated that the increased Pb in the recent sediments was of anthropogenic origin. The results of trace metal influxes showed that about 30% of total Pb and 15% of total Zn in the sediments in the 1990s were from anthropogenic sources. The combination of trace metal analysis, Pb isotopic composition and 210Pb dating in an estuary can provide vital information on the long-term accumulation of metals in sedie long-term accumulation of metals in sediments

  4. 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.

  5. Over one hundred years of trace metal fluxes in the sediments of the Pearl River Estuary, South China

    Energy Technology Data Exchange (ETDEWEB)

    Ip, C.C.M.; Li, X.D.; Zhang, G.; Farmer, J.G.; Wai, O.W.H.; Li, Y.S

    2004-11-01

    The rapid economic development in the Pearl River Delta (PRD) region in South China in the last three decades has had a significant impact on the local environment. Estuarine sediment is a major sink for contaminants and nutrients in the surrounding ecosystem. The accumulation of trace metals in sediments may cause serious environmental problems in the aquatic system. Thirty sediment cores were collected in the Pearl River Estuary (PRE) in 2000 for a study on trace metal pollution in this region. Heavy metal concentrations and Pb isotopic compositions in the four {sup 210}Pb-dated sediment cores were determined to assess the fluxes in metal deposits over the last one hundred years. The concentrations of Cu, Pb and Zn in the surface sediment layers were generally elevated when compared with the sub-surface layers. There has been a significant increase in inputs of Cu, Pb and Zn in the PRE since the 1970s. The results also showed that different sampling locations in the estuary received slightly different types of inputs. Pb isotopic composition data indicated that the increased Pb in the recent sediments was of anthropogenic origin. The results of trace metal influxes showed that about 30% of total Pb and 15% of total Zn in the sediments in the 1990s were from anthropogenic sources. The combination of trace metal analysis, Pb isotopic composition and {sup 210}Pb dating in an estuary can provide vital information on the long-term accumulation of metals in sediments.

  6. Evidencing the natural and anthropogenic processes controlling trace metals dynamic in a highly stratified estuary: The Krka River estuary (Adriatic, Croatia).

    Science.gov (United States)

    Cindri?, Ana-Marija; Garnier, Cédric; Oursel, Benjamin; Pižeta, Ivanka; Omanovi?, Dario

    2015-05-15

    Distributions of trace metals (TM), organic carbon, SPM and physico-chemical parameters were studied in the highly stratified Krka River estuary in winter/summer periods. The non-conservative behaviour of Zn, Cd, Pb and Cu in the brackish layer (plume), easily spotted due to very low inputs by the river, was mainly caused by their inputs from the pleasure boats, nautical marinas and harbour (e.g. release from antifouling paints). Contrarily, Ni and Co followed near-conservative behaviour. The extremely low SPM discharged by the river, resulted in a predominant dissolved fraction (>80%) of all TM, except Pb. Vertical scavenging, coupled with the long residence time, caused accumulation and progressive upstream increase of TM and SPM in the bottom seawater. Decrease of distribution coefficient (KD) in the brackish layer for winter period was ascribed to the change of SPM nature (terrestrial vs. biogenic), whereas a variable and increased biogenic component of SPM caused scattered KDs in summer. PMID:25752536

  7. 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 ?g/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)

  8. 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.

    1719-17-01

    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 (

  9. 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.

  10. Sources and distribution of organic matter in a river-dominated estuary (Winyah Bay, SC, USA)

    Science.gov (United States)

    Goñi, Miguel A.; Teixeira, Maria J.; Perkey, David W.

    2003-08-01

    The sources and distribution of organic matter (OM) in surface waters and sediments from Winyah Bay (South Carolina, USA) were investigated using a variety of analytical techniques, including elemental, stable isotope and organic biomarker analyses. Several locations along the estuary salinity gradient were sampled during four different periods of contrasting river discharge and tidal range. The dissolved organic carbon (DOC) concentrations of surface waters ranged from 7 mg l -1 in the lower bay stations closest to the ocean to 20 mg l -1 in the river and upper bay samples. There was a general linear relationship between DOC concentrations and salinity in three of the four sampling periods. In contrast, particulate organic carbon (POC) concentrations were significantly lower (0.1-3 mg l -1) and showed no relationship with salinity. The high molecular weight dissolved OM (HMW DOM) isolated from selected water samples collected along the bay displayed atomic carbon:nitrogen ratios ([C/N]a) and stable carbon isotopic compositions of organic carbon ( ?13C OC) that ranged from 10 to 30 and from -28 to -25‰, respectively. Combined, such compositions indicate that in most HMW DOM samples, the majority of the OM originates from terrigenous sources, with smaller contributions from riverine and estuarine phytoplankton. In contrast, the [C/N]a ratios of particulate OM (POM) samples varied significantly among the collection periods, ranging from low values of ˜5 to high values of >20. Overall, the trends in [C/N]a ratios indicated that algal sources of POM were most important during the early and late summer, whereas terrigenous sources dominated in the winter and early spring. In Winyah Bay bottom sediments, the concentrations of the mineral-associated OM were positively correlated with sediment surface area. The [C/N]a ratios and ?13C OC compositions of the bulk sedimentary OM ranged from 5 to 45 and from -28 to -23‰, respectively. These compositions were consistent with predominant contributions of terrigenous sources and lesser (but significant) inputs of freshwater, estuarine and marine phytoplankton. The highest terrigenous contents were found in sediments from the river and upper bay sites, with smaller contributions to the lower parts of the estuary. The yields of lignin-derived CuO oxidation products from Winyah Bay sediments indicated that the terrigenous OM in these samples was composed of variable mixtures of relatively fresh vascular plant detritus and moderately altered soil OM. Based on the lignin phenol compositions, most of this material appeared to be derived from angiosperm and gymnosperm vascular plant sources similar to those found in the upland coastal forests in this region. A few samples displayed lignin compositions that suggested a more significant contribution from marsh C 3 grasses. However, there was no evidence of inputs of Spartina alterniflora (a C 4 grass) remains from the salt marshes that surround the lower sections of Winyah Bay.

  11. 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.

  12. 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. 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.

  13. 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. ·

  14. Distributions of Core- and Polar- Archaeal Lipids in the Lower Pearl River and Estuary: Implications for TEX86 Proxies

    Science.gov (United States)

    Wang, J.; Zhang, C.; Zhu, C.; Wei, Y.; Dong, H.; Liu, W.

    2011-12-01

    Core isoprenoidal glycerol dibiphytanyl dlycerol tetraethers (C-iGDGTs) are the most widespread archaeal lipids in sediments and water, and have been used to construct a molecular proxy, TEX86, for studying past sea surface temperatures. However, recent analyses of intact polar (IP)-iGDGTs that are indicative of living archaea suggest that IP-iGDGTs produced in situ in marine sediments may subsequently convert IP-iGDGTs to C-iGDGTs after the cell death, thus compromising the validity of TEX86 for paleoclimate research. To help address this question, we investigated the distribution and abundance of IP- and C- iGDGTs in suspended particulates and surface sediments from the lower Pearl River and estuary. Our results show a strong positive correlation between the C- and P-iGDGTs pools, especially the iGDGT-0 (R2 = 0.786, p<0.001), iGDGT-1 (R2 = 0.920, p<0.001), and crenarchaeol (R2 = 0.871, p<0.001), suggesting that aquatic archaeal lipids are mostly derived from in situ production in the river water and/or sediments, and a minor fraction of these lipids are terrestrially-sourced. Methanogens (belonging to Euryarchaeota) may be an important source of iGDGTs in water and sediments of Pearl River estuary, which may further complicate the use of TEX86 that is based on planktonic Crenarchaeota.

  15. 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 239 240Pu, 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 239 240Pu 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., 239 240Pu/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 239 240Pu and 137Cs observed in fresh water sampl>137Cs observed in fresh water samples were primarily functions of the suspended load. Approximately 60-70% of the annual downstream transport of 239 240Pu 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

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

    Directory of Open Access Journals (Sweden)

    Hong-Li Li

    2009-01-01

    Full Text Available Spectra, salinity, total suspended solids (TSS, in mg/L and colored dissolved organic matter (CDOM, ag(400 at 400 nm sampled in stations in 44 different locations on December 18, 19 and 21, in 2006 were measured and analyzed. The studied field covered a large variety of optically different waters, the absorption coefficient of CDOM ([ag(400] in m-1 varied between 0.488 and 1.41 m-1, and the TSS concentrations (mg/L varied between 7.0 and 241.1 mg/L. In order to detect salinity of the Pearl River Estuary, we analyzed the spectral properties of TSS and CDOM, and the relationships between field water reflectance spectra and water constituents’ concentrations based on the synchronous in-situ and satellite hyper-spectral image analysis. A good correlation was discovered (the positive correlation by linear fit, between in-situ reflectance ratio R680/R527 and TSS concentrations (R2 = 0.65 for the salinity range of 1.74-22.12. However, the result also showed that the absorption coefficient of CDOM was not tightly correlated with reflectance. In addition, we also observed two significant relationships (R2 > 0.77, one between TSS concentrations and surface salinity and the other between the absorption coefficient of CDOM and surface salinity. Finally, we develop a novel method to understand surface salinity distribution of estuarine waters from the calibrated EO-1 Hyperion reflectance data in the Pearl River Estuary, i.e. channels with high salinity and shoals with low salinity. The EO-1 Hyperion derived surface salinity and TSSconcentrations were validated using in-situ data that were collected on December 21, 2006, synchronous with EO-1 Hyperion satellite imagery acquisition. The results showed that the semi-empirical relationships are capable of predicting salinity from EO-1 Hyperion imagery in the Pearl River Estuary (RMSE < 2‰.

  17. 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 (pconservation 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.

  18. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Ip, C.C.M. [Department of Civil and Structural Engineering, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong (China); Li, X.D. [Department of Civil and Structural Engineering, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong (China)]. E-mail: cexdli@polyu.edu.hk; Zhang, G. [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Wong, C.S.C. [Department of Civil and Structural Engineering, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong (China); Zhang, W.L. [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China)

    2005-12-15

    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.

  20. 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 yearsup>-4) per year

  1. Particle Association of Enterococcus and Total Bacteria in the Lower Hudson River Estuary, USA

    Directory of Open Access Journals (Sweden)

    Elizabeth Suter

    2011-10-01

    Full Text Available Bacterial particle association has important consequences for water-quality monitoring and modeling. Particle association can change vertical and horizontal transport of bacterial cells, as well as patterns of persistence and production. In this study, the abundance and particle association of total bacteria and the fecal-indicator, Enterococcus, were quantified between June and October 2008 in the lower Hudson River Estuary (HRE. Twelve sites were sampled, including mid-channel, near shore, and tributary habitats, plus a sewage outfall. Total bacterial cell counts averaged 9.2 × 109 ± 6.4 × 109 cell l–1 (1 standard deviation, comparable to previous sampling in the HRE. Unlike earlier studies, bacterial abundance did not change consistently along the north/south estuarine salinity gradient. Enterococcus concentrations were highly variable, but mid-channel stations had significantly lower values than other habitat categories. Counts of total bacteria and Enterococcus were both correlated with turbidity, which was also significantly lower at mid-channel stations. A larger fraction of Enterococci were associated with particles (52.9 ± 20.9%, 1 standard deviation than in the pool of total bacteria (23.8 ± 15.0%. This high frequency of particle association, relative to total bacteria, could cause Enterococcus to be preferentially retained near input sources because of enhanced deposition to bottom sediments, where they would be available for later resuspension. In turn, retention and resuspension in nearshore environments may explain the observed cross-channel variability of turbidity and Enterococcus. Assessments and predictive models of estuarine water quality may be improved by incorporating cross-channel variability and the effects of particle association on key indicators.

  2. 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.

  3. On the 234,238U isotope systematics in two tropical estuaries: the Amazon and Fly Rivers.

    Science.gov (United States)

    Swarzenski, P. W.; Campbell, P. L.; Porcelli, D.

    2003-12-01

    Natural concentrations of 238U and d234U were determined in estuarine surface waters of the Amazon and Fly (Papua New Guinea) Rivers to investigate U transport phenomena across river-dominated land-sea margins. On the Amazon shelf, salinity-property plots of dissolved organic carbon (DOC), pH and total suspended matter (TSM) revealed two vastly contrasting water masses that were energetically mixed. In this mixing zone, the distribution of uranium isotopes was highly non-conservative and exhibited extensive removal from the water column. Uranium removal was most pronounced within a salinity range of 0 to 16.6, and is likely the result of scavenging and flocculation reactions with inorganic (i.e., Fe/Mn oxides) and organic colloids/particles. Removal of uranium may also be closely coupled to exchange and resuspension processes at the sediment/water interface. In the Fly River estuary, 238U appears to exhibit a reasonably conservative distribution as a function of salinity. The absence of observed U removal does not necessarily imply non-reactivity, but instead may record an integration of concurrent U removal and release processes. There is not a linear correlation between d234U versus 1/238U that would imply simple two component mixing. It is likely that resuspension of bottom sediments, prolonged residence times in the lower reaches of the Fly River, and energetic particle-colloid interactions contribute to the observed estuarine U distribution. The supply of uranium discharged from humid, tropical river systems to the sea appears to be foremost influenced by particle/water interactions that are ultimately governed by the particular physiographic and hydrologic characteristics of an estuary.

  4. 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.

  5. 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 ...

  6. 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)

  7. 77 FR 15722 - Takes of Marine Mammals Incidental to Specified Activities; Russian River Estuary Management...

    Science.gov (United States)

    2012-03-16

    ...assigned to estuary management activities. The training...water surface elevation management event, the biologist...to California State Parks and Stewards, and would...and during water level management events; start and...g., temperature, wind, etc.);...

  8. CO2 flux and seasonal variability in the turbidity maximum zone and surrounding area in the Changjiang River estuary

    Science.gov (United States)

    Li, Xuegang; Song, Jinming; Yuan, Huamao; Li, Ning; Duan, Liqin; Qu, Baoxiao

    2015-01-01

    The turbidity maximum zone (TMZ) is one of the most important regions in an estuary. However, the high concentration of suspended material makes it difficult to measure the partial pressure of CO2 ( pCO2) in these regions. Therefore, very little data is available on the pCO2 levels in TMZs. To relatively accurately evaluate the CO2 flux in an example estuary, we studied the TMZ and surrounding area in the Changjiang (Yangtze) River estuary. From seasonal cruises during February, August, November 2010, and May 2012, the pCO2 in the TMZ and surrounding area was calculated from pH and total alkalinity (TA) measured in situ, from which the CO2 flux was calculated. Overall, the TMZ and surrounding area acted as a source of atmosphere CO2 in February and November, and as a sink in May and August. The average FCO2 was -9, -16, 5, and 5 mmol/(m2·d) in May, August, November, and February, respectively. The TMZ's role as a source or sink of atmosphere CO2 was quite different to the outer estuary. In the TMZ and surrounding area, suspended matter, phytoplankton, and pH were the main factors controlling the FCO2, but here the influence of temperature, salinity, and total alkalinity on the FCO2 was weak. Organic carbon decomposition in suspended matter was the main reason for the region acting as a CO2 source in winter, and phytoplankton production was the main reason the region was a CO2 sink in summer.

  9. 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)

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

    Energy Technology Data Exchange (ETDEWEB)

    Xianzhi Peng; Zhendi Wang; Yiyi Yu (and others) [Chinese Academy of Sciences, Guangzhou (China). State Key Laboratory of Organic Geochemistry

    2008-11-15

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

  11. 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

  12. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Shi Jianbo [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085 (China); Department of Civil and Structural Engineering, Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong); Ip, Carman C.M. [Department of Civil and Structural Engineering, Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong); Zhang Gan [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Jiang Guibin [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085 (China); Li Xiangdong, E-mail: cexdli@polyu.edu.h [Department of Civil and Structural Engineering, Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong)

    2010-05-15

    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 {sup 210}Pb dating technique, the historical changes in the concentrations and influxes of Hg in the last 100 years were also investigated. The variations in Hg influxes in sediment cores obviously correlate with the economic development and urbanization that has occurred the PRD region, especially in the last three decades. - The spatial and historical changes of Hg in sediment reflect the industrial development and urbanization of the region in south China.

  14. 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

  15. 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)

  16. 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.

  17. 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 t

  18. 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 investigators); 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.

  19. 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.

  20. Variations in Branched Tetraether Lipids in the Lower Pearl River and Estuary: Impact on bGDGT Proxies

    Science.gov (United States)

    Zhang, C.; Wang, J.; Wei, Y.; Zhu, C.; Huang, L.; Dong, H.

    2011-12-01

    Branched glycerol dibiphytanyl glycerol tetraethers (bGDGTs) are known as bacterial lipids that occur widely in terrestrial environments, particularly in peat bogs and soil. A number of proxies have been developed using bGDGTs, which have been applied to marine sediments as terrestrial signals. We examined the abundance and distribution of bGDGTs in both core- (C) and polar- (P) lipid (L) fractions from the water column and surface sediments in the lower Pearl River (PR) and estuary. A number of soil samples in the lower PR drainage basin were also collected. The results showed in situ production of bGDGTs and difference in abundance and structure of bGDGTs between the water column and surface sediments. The average PL accounted for over 50% of total bGDGTs in the former but less than 10% in the latter, suggesting that the water column contains a significant population of living organisms that produce bGDGTs whereas the surface sediment contains mostly bGDGTs from nonliving cells. The soil samples also showed predominance of C-bGDGTs with average P-bGDGTs accounting for about 8% of total bGDGTs. The abundance of C-bGDGTs and P-bGDGTs decreased sharply from the lower PR to the estuary in the water column; whereas in surface sediments, only C-bGDGTs showed significant decrease. The bGDGT-based proxies (BIT, CBT, and MBT) showed different patterns of variation with BIT decreasing in both C- and P- lipid fractions from the lower PR to estuary and MBT in the C- lipid fraction remaining constant. These results indicate that the lower PR and estuary is a dynamic system, which experiences considerable changes in the abundance and structure of bGDGTs. This study also indicates the complexity of the estuary system and cautions need to be excised when using bGDGT-based proxies for paleo-continental or soil pH studies in continental margins.

  1. 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.

  2. 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.

  3. 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.

  4. 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)

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. Paleo-Reconstruction of Carbon Cycling in Large-River Delta-Front Estuaries: Use of Molecular Biomarkers

    Science.gov (United States)

    Bianchi, T. S.

    2014-12-01

    The burial of organic carbon (OC) in river deltas and continental margins worldwide account for approximately 90% of the carbon burial in the ocean. In particular, sediments in large-river delta-front estuaries have been shown to be repositories and integrators of land-use change across expansive watersheds that drain the continents to the ocean. Thus, separating natural and human-driven changes in the transport of terrestrial organic carbon (TOC) to ocean is important in understanding the effects of climate change on TOC fluxes. Molecular biomarkers of TOC (e.g., lignin phenols, fatty acids, sterols) in LDE sediments have been used extensively to reconstruct of carbon cycling changes that are reflective of land-use change in the watersheds. However, due to the highly variable hydrologic regimes across continents, continental margins (e.g., active versus passive), and coastal dynamics in LDEs, the fate and transport of these molecular biomarkers varies considerably. Here I will discuss some of the key molecular biomarkers that have been used to date in such historical reconstruction exercises in LDEs (e.g., Mississippi/Atchafalaya, Yangtze, Yellow, Ganges-Brahmaputra, Colville Rivers), and explore how margin-type, residence time of transport, redox, and molecular stability, to name a few, impact the utility of using different biomarkers in paleo-reconstruction studies.

  10. 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.

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

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

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

    Science.gov (United States)

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

    2008-06-01

    The benthic macroinvertebrates of the Nakdong River estuary were sampled at three different habitats: two salt marsh ( Scirpus triqueter and Phragmites australis) beds and a bare intertidal flat. Fishes were sampled in the main channel. The trophic importance of marsh vascular plants, microphytobenthos, and riverine and channel particulate organic matter to macroinvertebrate and fish production was studied using stable carbon and nitrogen isotope tracers. There was a dramatic change in coverage of macrophytes (salt marshes and seagrass) after the construction of an estuarine barrage in 1987 in the Nakdong River estuary, with the S. triqueter bed increasing, the P. australis bed decreasing, and Zostera marina habitats being nearly lost. Although the invertebrate ? 13C were within a narrower range than those of the primary producers, the values varied considerably among consumers in these habitats. However, the isotope signatures of consumers showed similarities among different habitats. Cluster analysis based on their isotopic similarity suggested that the isotope variability among species was related more to functional feeding groups than to habitats or taxonomic groups. While ? 13C values of suspension feeders were close to that of the channel POM (mainly phytoplankton), other benthic feeders and predators had ? 13C similar to that of microphytobenthos. Isotopic mixing model estimates suggest that algal sources, including microphytobenthos and phytoplankton, play an important role in supporting the benthic food web. Despite the huge productivity of emergent salt marshes, the contribution of the marsh-derived organic matter to the estuarine food webs appears to be limited to some nutrition for some invertebrates just within marsh habitats, with little on the bare intertidal flats or in the channel fish communities. Isotope signatures of the channel fishes also confirm that algal sources are important in supporting fish nutrition. Our findings suggest that benthic and pelagic microalgae made a large contribution to consumer diets, while marsh plants may not have a large role in supporting food webs in this estuarine system.

  13. 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.

  14. 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.

  15. Application of denaturing gradient gel electrophoresis for detection of bacterial and yeast communities along a salinity gradient in the estuary of the Cachoeira River in Brazil.

    Science.gov (United States)

    Rodrigues, C S P; Souza, S S; Rezende, R P; Silva, A; Andrioli, J L; Costa, H; Fontana, R; Dias, J C T

    2013-01-01

    An estuary is a transition zone between freshwater and marine ecosystems, resulting in dilution of seawater. Estuaries are also considered environments of intense biological activity related to the processes of nutrient cycling. The aim of this study was to evaluate the microbial community composition along a salinity gradient in the estuary of the Cachoeira River, located in southern Bahia, Brazil. The analysis of bacterial and yeast communities was performed by determining the denaturing gradient gel electrophoresis band richness. Formation of zones with similar profiles of bands was observed, and the increasing richness at the intermediate zone demonstrated a clear spatial distinction of communities depending on salinity. In addition, the dissolved oxygen content, temperature, pH, salinity, and dissolved inorganic nutrient contents (NH3(+), NO2(-), NO3(-), PO4(-)) were determined. Nutrients were distributed in similar patterns, with decreasing concentrations as the salinity increases. PMID:23765981

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

    Digital Repository Service at National Institute of Oceanography (India)

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

    2014-01-01

    This study was aimed (1) to evaluate the water quality of Chalakudy river, the fifth longest (145.5 km) river of Kerala (South India), by assessing the general hydrochemical parameters like temperature, dissolved oxygen (DO), salinity and chemical...

  17. Impact of Iron Ore Tailing on Foraminifera of the Uppateru River Estuary, East Coast of India

    OpenAIRE

    Addula Nallapa Reddy; Kambham Reddeppa Reddy; Reddy, Balam C. S. R.; Nadimikeri Jayaraju

    2011-01-01

    Benthic foraminiferal assemblages have been used to determine the effects of Iran ore tailing pollution on the marine environment. The present paper attempts to unveil pollution impact as responded by foraminiferal species of Uppateru estuary. The faunal data thus generated is compared with earlier data sets for possible adverse effects. There has been substantial reduction in total foraminiferal number (TFN), from 574 in 2006 to 213 in 2008 species (st.no.3) per10 gram sediment. Even the tot...

  18. Tracking historical lead pollution in the coastal area adjacent to the Yangtze River Estuary using lead isotopic compositions

    Energy Technology Data Exchange (ETDEWEB)

    Hao Yunchao [College of Marine Geosciences, Ocean University of China, 238 Songling Road, Qingdao 266100, Shandong (China); Guo Zhigang [College of Marine Geosciences, Ocean University of China, 238 Songling Road, Qingdao 266100, Shandong (China)], E-mail: guozgg@ouc.edu.cn; Yang Zuosheng; Fan, Dejiang [College of Marine Geosciences, Ocean University of China, 238 Songling Road, Qingdao 266100, Shandong (China); Fang Ming [Department of Chemical Engineering, Hong Kong University of Science and Technology, Clearwater Bay, Hong Kong (China); Li Xiangdong [Department of Civil and Structural Engineering, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong (China)

    2008-12-15

    The rapid economic development in the Yangtze River Delta (YRD), China in the last three decades has had a significant impact on the environment of the East China Sea (ECS). Lead isotopic compositions of a {sup 210}Pb dated sediment core collected from the coastal ECS adjacent to the Yangtze River Estuary were analyzed to track the Pb pollution in the region. The baseline Pb concentration in the coastal ECS sediments before the industrialization in China was 32 {mu}g g{sup -1}, and the corresponding {sup 206}Pb/{sup 207}Pb ratio was 1.195. The high-resolution profiles of Pb flux and {sup 206}Pb/{sup 207}Pb ratios had close relationships with the economic development and the history of the use of leaded gasoline in China, and they were clearly different from those of most European countries and United States. - The combination of Pb concentration, sedimentary flux, Pb isotopic composition and {sup 210}Pb dating in the coastal ECS sediments revealed the historical Pb pollution in China.

  19. 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

  20. Tracking historical lead pollution in the coastal area adjacent to the Yangtze River Estuary using lead isotopic compositions

    International Nuclear Information System (INIS)

    The rapid economic development in the Yangtze River Delta (YRD), China in the last three decades has had a significant impact on the environment of the East China Sea (ECS). Lead isotopic compositions of a 210Pb dated sediment core collected from the coastal ECS adjacent to the Yangtze River Estuary were analyzed to track the Pb pollution in the region. The baseline Pb concentration in the coastal ECS sediments before the industrialization in China was 32 ?g g-1, and the corresponding 206Pb/207Pb ratio was 1.195. The high-resolution profiles of Pb flux and 206Pb/207Pb ratios had close relationships with the economic development and the history of the use of leaded gasoline in China, and they were clearly different from those of most European countries and United States. - The combination of Pb concentration, sedimentary flux, Pb isotopic composition and 210Pb dating in the coastal ECS sediments revealed the historical Pb pollution in China

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

    Energy Technology Data Exchange (ETDEWEB)

    Peng Xianzhi [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 511 Kehau Street, Guangzhou 510640 (China)], E-mail: pengx@gig.ac.cn; Wang Zhendi [Environmental Science and Technology Centre, Environment Canada, 335 River Road, Ottawa, Ontario K1A 0H3 (Canada); Yu Yiyi; Tang Caiming; Lu Hong; Xu Shiping; Chen Fanrong; Mai Bixian; Chen Shejun; Li Kechang [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 511 Kehau Street, Guangzhou 510640 (China); Yang Chun [Environmental Science and Technology Centre, Environment Canada, 335 River Road, Ottawa, Ontario K1A 0H3 (Canada)

    2008-11-15

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

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

    Science.gov (United States)

    Xu, Yonghang; Sun, Qinqin; Yi, Liang; Yin, Xijie; Wang, Aijun; Li, Yunhai; Chen, Jian

    2014-09-15

    Two sedimentary cores in the Minjiang River estuary (SE China) are documented for grain size, clay minerals, heavy metals, magnetic parameters and Pb isotopes to investigate the source and historical variation of heavy metals. The MJK9 core was collected outside of the Minjiang River estuary, and the core is composed of mixed sediments, of which ~70% from the Yangtze River and 30% from the Minjiang River. It is thus difficult to be used for tracing the human activity along the Minjiang River. In contrast, the sediments of MJK16 core which was collected in a nearshore area are primarily from the Minjiang River. The enrichment factors of the sediments were 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. PMID:24995639

  3. Heavy metal pollution in the Guadiamar river and the Guadalquivir estuary (South West Spain)

    OpenAIRE

    Cabrera, Francisco; Soldevilla, Marina; Cordón, Rosario; Arambarri, Pablo de

    1987-01-01

    The Guadalquivir river is the most important course of water of South West Spain. Its tributary, the Guadiamar river, joins the Guadalquivir near its mouth at C~diz Gulf in the Spanish South Atlantic coast, just after skirting the marshy part of the Do~ana National Park. The upper Guadiamar river receives through its tributary the Agrio river the drainage water from an opencast-worked polymetallic sulphide deposit and the effluents from a plant for the treatment and concentration of mineral. ...

  4. 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.

  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

    Ogri, O. R.; Malu, S. P.; Ubwa, S. T.

    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. 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.

  7. 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.

  8. 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

  9. Spatial and temporal distribution in density and biomass of two Pseudodiaptomus species (Copepoda: Calanoida) in the Caeté river estuary (Amazon region--North of Brazil).

    Science.gov (United States)

    Magalhães, A; Costa, R M; Liang, T H; Pereira, L C C; Ribeiro, M J S

    2006-05-01

    Spatial and temporal density and biomass distribution of the planktonic copepods Pseudodiaptomus richardi and P. acutus along a salinity gradient were investigated in the Caeté River Estuary (North-Brazil) in June and December, 1998 (dry season) and in February and May, 1999 (rainy season). Copepod biomass was estimated using regression parameters based on the relation of dry weight and body length (prosome) of adult organisms. The Caeté River Estuary was characterized by high spatial and temporal variations in salinity (0.8-37.2). Exponential length-weight relationships were observed for both Pseudodiaptomus species. Density and biomass values oscillated between 0.28-46.18 ind. m-3 and 0.0022-0.3507 mg DW. m-3 for P. richardi; and between 0.01-17.02 ind. m-3 and 0.0005-0.7181 mg DW. m-3 for P. acutus. The results showed that the contribution of P. richardi for the secondary production in the Caeté River Estuary is more important in the limnetic zone than in other zones where euhaline-polyhaline regimes were predominant. However, it was not possible to observe a clear pattern of spatial and temporal distribution for P. acutus. PMID:16862295

  10. The role of class I integrons in the dissemination of sulfonamide resistance genes in the Pearl River and Pearl River Estuary, South China.

    Science.gov (United States)

    Chen, Baowei; Liang, Ximei; Nie, Xiangping; Huang, Xiaoping; Zou, Shichun; Li, Xiangdong

    2015-01-23

    Antibiotic resistance genes (ARGs), as a newly emerging contaminant, are unique because they are disseminated through horizontal gene transfer in the environment. In the present study, a class 1 integron gene (int1) and various ARGs (sul1, sul2, sul3, qnrS, and ermB) were measured in water and sediment samples from the Pearl River (PR) to the Pearl River Estuary (PRE), where there is a distinct gradient in anthropogenic impact. The int1, sul1, and sul2 genes were detected in all samples, and their concentrations exhibited a clear trend of decline consistent with anthropogenic impact. Both the int1 and sul genes had dynamically migrated between water and sediments. The relative abundance of the int1 gene normalized to the 16S rRNA gene correlated significantly with the total concentrations of antibiotics in water and sediments. Good correlations were also observed between the abundance of int1 and each type of sul gene in the samples. However, the sul1 gene showed a much stronger relationship with int1 in different seasons, probably due to the presence of sul1 in the conserved region of class 1 integron. Our results strongly support that integrons play an important role in the dissemination of ARGs in human-impacted aquatic environments. PMID:24994022

  11. 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

  12. Modeling the influence of river discharge on salt intrusion and residual circulation in Danshuei River estuary, Taiwan

    Science.gov (United States)

    Liu, W.-C.; Chen, W.-B.; Cheng, R.T.; Hsu, M.-H.; Kuo, A.Y.

    2007-01-01

    A 3-D, time-dependent, baroclinic, hydrodynamic and salinity model was implemented and applied to the Danshuei River estuarine system and the adjacent coastal sea in Taiwan. The model forcing functions consist of tidal elevations along the open boundaries and freshwater inflows from the main stream and major tributaries in the Danshuei River estuarine system. The bottom friction coefficient was adjusted to achieve model calibration and verification in model simulations of barotropic and baroclinic flows. The turbulent diffusivities were ascertained through comparison of simulated salinity time series with observations. The model simulation results are in qualitative agreement with the available field data. The validated model was then used to investigate the influence of freshwater discharge on residual current and salinity intrusion under different freshwater inflow condition in the Danshuei River estuarine system. The model results reveal that the characteristic two-layered estuarine circulation prevails most of the time at Kuan-Du station near the river mouth. Comparing the estuarine circulation under low- and mean flow conditions, the circulation strengthens during low-flow period and its strength decreases at moderate river discharge. The river discharge is a dominating factor affecting the salinity intrusion in the estuarine system. A correlation between the distance of salt intrusion and freshwater discharge has been established allowing prediction of salt intrusion for different inflow conditions. ?? 2007 Elsevier Ltd. All rights reserved.

  13. Study of the dynamic behaviour of the estuary of the Guadalquivir river

    International Nuclear Information System (INIS)

    One of the largest rivers in Spain, the Guadalquivir, is showing signs of two types of contamination. The first is caused by effluents from industry and settlements on the river, which include Seville. The second is due to penetration by salt water from the Atlantic, which is carried more than 100km by tides. Both types of contamination, and especially the second, seriously affect the water collected for irrigating rice fields, which can tolerate a maximum salinity of 0.8g/l. The flow of fresh water carried by the river is regulated in its final stretch by the Alcala del Rio dam upstream from Seville. To determine the influence of variations in river discharge on the penetration of sea-water and on the dilution of salt water and contaminated water, twelve 82Br point injections of 4Ci each were carried out at different spots; the passage of the radioactive cloud and its dilution were then monitored along the river. A single tritium injection of 30Ci was also made at the foot of the Alcala del Rio dam and the passage of the tracer was studied from three stations, the last of which was situated at the mouth of the river where it enters the Atlantic. The field data were used to prepare a mathematical model which yielded very interesting information, suggesting ways in which the use of the river could be improved. (author)

  14. 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.

  15. 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.

  16. 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-rep>-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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Yuanzhi; Lin Hui [Institute of Space and Earth Information Science, Yuen Yuen Research Centre for Satellite Remote Sensing, Chinese University of Hong Kong, Shatin, N.T. (Hong Kong); Chen, Chuqun [South China Institute of Oceanology, Chinese Academy of Sciences, Guangzhou (China); Chen Liding [Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing (China); Zhang Bing [Center for Earth Observation and Digital Earth, Chinese Academy of Sciences, Beijing (China); Gitelson, Anatoly A, E-mail: yuanzhizhang@cuhk.edu.hk [Center for Advanced Land Management Information Technologies (CALMIT), School of Natural Resources, University of Nebraska-Lincoln (United States)

    2011-04-15

    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{sup -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{sup -3} and total suspended matter from 9.9 to 21.5 g m{sup -3}. A close relationship was found between chl-a concentration and total suspended matter concentration with the determining coefficient (R{sup 2}) above 0.89. The MBR calculated in the spectral bands of MODIS proved to be a good proxy for chl-a concentration (R{sup 2} > 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{sup -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.

  18. 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.

  19. Compound- and mixture-specific differences in resistance to polycyclic aromatic hydrocarbons and PCB-126 among Fundulus heteroclitus subpopulations throughout the Elizabeth River estuary (Virginia, USA).

    Science.gov (United States)

    Clark, Bryan W; Cooper, Ellen M; Stapleton, Heather M; Di Giulio, Richard T

    2013-09-17

    Atlantic killifish (Fundulus heteroclitus) inhabiting the Atlantic Wood Industries Superfund Site (Elizabeth River, Portsmouth, VA, USA) are resistant to the acute toxicity and cardiac teratogenesis caused by high levels of polycyclic aromatic hydrocarbons (PAHs) from creosote. The resistance is linked to down regulation of the aryl hydrocarbon receptor (AHR) pathway. We investigated the association between CYP1 activity, as a marker of potential AHR pathway suppression, and contaminant resistance in killifish subpopulations from sites throughout the estuary that varied significantly in PAH contamination level. Adult killifish and sediments were collected from seven sites across approximately 13.7 km in river length within the estuary and from a nearby reference site. Sediment PAH levels were determined using gas chromatography mass spectrometry. Embryos obtained via manual spawning were exposed to individual AHR agonists and PAH mixtures 24 h post fertilization (hpf); CYP1 activity was determined by in ovo ethoxyresorufin-o-deethylase (EROD) at 96 hpf, and cardiac deformity severity was scored at 144 hpf. The total PAH levels measured among the sites varied from approximately 200 to 125,000 ng/g dry sediment. Overall, the resistance to teratogenesis was strongest in the subpopulations from sites in or closest to the major PAH contamination sites, but even embryos from less-contaminated sites within the Elizabeth River demonstrated at least partial resistance to many challenges. Surprisingly, all of the subpopulations tested were highly resistant to PCB-126 (3,3',4,4',5-pentachlorobiphenyl). However, the degree of CYP1 activity response varied significantly among subpopulations and did not always correlate strongly with resistance to teratogenesis; some subpopulations resisted the cardiac teratogenesis caused by the challenges at doses that still elicited strong EROD induction. Our results suggest that there is variation in the adaptive phenotype exhibited by laboratory-spawned embryos from killifish subpopulations throughout the estuary. Furthermore, the results show that contaminants have affected killifish subpopulations throughout the estuary, even in sites with lower levels of PAHs. PMID:24003986

  20. IDENTIFICATION OF 5?-STANONES AS TRACERS FOR INPUT FROM SEWAGE AND ANIMAL HUSBANDRY IN SURFACE SEDIMENTS FROM THE CROSS RIVER ESTUARY, S.E. NIGER DELTA, NIGERIA

    Directory of Open Access Journals (Sweden)

    BERND R.T. SIMONEIT

    2010-03-01

    Full Text Available The identification of 5?-stanones and their 5?-stereoisomeric counterparts in extracts of sediments from the Cross River estuary was achieved by gas chromatography-mass spectrometry. The concentrations of the stanones varied between 0.02 and 3.89 mgkg-1 with an overall average of 0.9 mgkg-1. The highest concentrations were measured at the lower estuary, with 5?-stigmastan-3-one as maximum, and at the upper estuary a minimum value for 5?-cholestan-3-one. The elevated levels of 5?-stanones in sediments of the lower estuary may be attributed to the proximity of high human and animal populations and storm resuspension of sediments as a consequence of high tidal cycles. The geochemical ratio of 5?-cholestan-3-one/(5?-cholestan-3-one + 5?-cholestan-3-one is in the range of 0.28-0.83 and indicates pollution by urban sewage, while the ratio of 5?-cholestan-3-one/5?-stigmastan-3-one, with values ranging from 0.09 to 2.92 is a more diagnostic indicator of fecal pollution from ruminant husbandry in the region.

  1. 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.

  2. Estimating bankfull discharge and depth in ungauged estuaries

    Science.gov (United States)

    Gisen, Jacqueline Isabella Anak; Savenije, Hubert H. G.

    2015-04-01

    It is difficult to measure river discharge accurately in an estuary, and particularly, in the region where the tidal flow dominates over the river discharge. River discharge is important for the morphology and hydrodynamics of estuaries as it influences the salt intrusion process, tidal dynamics, freshwater supply (water resources management), and the occurrence of floods. Here we try to derive river regime characteristics from the seaward end: the estuary. It is found that there are empirical relationships that link the geometry of an estuary to its river regime, which can be used to estimate river discharge characteristics with the least of data available. The aims of this study are: (1) to derive empirical relations between geometrical characteristics of estuaries and the bankfull discharge; (2) to explore a physical explanation for this relation; and (3) to estimate the bankfull discharge in estuaries. The physical connection between an estuary and its river regime is found by combining estuary shape analysis, tidal dynamic analysis, and Lacey's hydraulic geometry theory. The relationships found between the estuary depth, width, and bankfull river discharge have been tested in 23 estuaries around the world (including seven recently surveyed estuaries). From the analysis, it shows that the depth of an estuary is a function of the bankfull flood discharge to the power of 1/3, which is in agreement with Lacey's formula. This finding not only provides a method to estimate estuary depth, it also allows estimating flood discharge characteristics from readily available estuary shape indicators.

  3. Tidal wetlands of the Yaquina and Alsea River estuaries, Oregon: Geographic Information Systems layer development and recommendations for National Wetlands Inventory revisions

    Science.gov (United States)

    Brophy, Laura S.; Reusser, Deborah A.; Janousek, Christopher N.

    2013-01-01

    Geographic Information Systems (GIS) layers of current, and likely former, tidal wetlands in two Oregon estuaries were generated by enhancing the 2010 National Wetlands Inventory (NWI) data with expert local field knowledge, Light Detection and Ranging-derived elevations, and 2009 aerial orthophotographs. Data were generated for two purposes: First, to enhance the NWI by recommending revised Cowardin classifications for certain NWI wetlands within the study area; and second, to generate GIS data for the 1999 Yaquina and Alsea River Basins Estuarine Wetland Site Prioritization study. Two sets of GIS products were generated: (1) enhanced NWI shapefiles; and (2) shapefiles of prioritization sites. The enhanced NWI shapefiles contain recommended changes to the Cowardin classification (system, subsystem, class, and/or modifiers) for 286 NWI polygons in the Yaquina estuary (1,133 acres) and 83 NWI polygons in the Alsea estuary (322 acres). These enhanced NWI shapefiles also identify likely former tidal wetlands that are classified as upland in the current NWI (64 NWI polygons totaling 441 acres in the Yaquina estuary; 16 NWI polygons totaling 51 acres in the Alsea estuary). The former tidal wetlands were identified to assist strategic planning for tidal wetland restoration. Cowardin classifications for the former tidal wetlands were not provided, because their current hydrology is complex owing to dikes, tide gates, and drainage ditches. The scope of this project did not include the field evaluation that would be needed to determine whether the former tidal wetlands are currently wetlands, and if so, determine their correct Cowardin classification. The prioritization site shapefiles contain 49 prioritization sites totaling 2,177 acres in the Yaquina estuary, and 39 prioritization sites totaling 1,045 acres in the Alsea estuary. The prioritization sites include current and former (for example, diked) tidal wetlands, and provide landscape units appropriate for basin-scale wetland restoration and conservation action planning. Several new prioritization sites (not included in the 1999 prioritization) were identified in each estuary, consisting of NWI polygons formerly classified as nontidal wetland or upland. The GIS products of this project improve the accuracy and utility of the NWI data, and provide useful tools for estuarine resource management.

  4. 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.

  5. 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 outsio the mudflats and tidal marsh areas outside of diked regions and then improve the estuarine habitats for salmon migration

  6. 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

  7. 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.

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

    International Nuclear Information System (INIS)

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

  9. Brominated flame retardants in mangrove sediments of the Pearl River Estuary, South China: spatial distribution, temporal trend and mass inventory.

    Science.gov (United States)

    Zhang, Zai-Wang; Sun, Yu-Xin; Sun, Kai-Feng; Xu, Xiang-Rong; Yu, Shen; Zheng, Tian-Ling; Luo, Xiao-Jun; Tian, Yun; Hu, Yong-Xia; Diao, Zeng-Hui; Mai, Bi-Xian

    2015-03-01

    Sediments were collected from three mangrove wetlands in the Pearl River Estuary (PRE) of South China to investigate spatial and temporal distributions of polybrominated diphenyl ethers (PBDEs), decabromodiphenyl ethane (DBDPE) and 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE). Concentrations of ?PBDEs, DBDPE and BTBPE in mangrove sediments of the PRE ranged from 1.25-206, 0.364-34.9, and not detected-0.794 ng g(-1) dry weight, respectively. The highest concentrations of ?PBDEs, DBDPE and BTBPE were found at the mangrove wetland from Shenzhen, followed by Zhuhai and Guangzhou, showing the dependence on the proximity to urban areas. PBDEs were the predominant brominated flame retardants (BFRs) in mangrove sediments. The concentrations of ?PBDEs, DBDPE and BTBPE in sediment cores showed an increasing trend from the bottom to top layers, reflecting the increasing usage of these BFRs. The inventories of ?PBDEs, DBDPE and BTBPE in mangrove sediments were 1962, 245, and 4.10 ng cm(-2), respectively. This is the first study to report the occurrence of DBDPE and BTBPE in mangrove ecosystems. PMID:25482977

  10. Species diversity of the old genus Navicula Bory (Bacillariophyta on intertidal sand-flats in the Nakdong River estuary, Korea

    Directory of Open Access Journals (Sweden)

    Gyeong-je Joh

    2013-12-01

    Full Text Available Remarkable diversity of diatom taxa occurs in intertidal sand-flats of the Nakdong River estuary, one of the most dynamic and productive ecosystem in Korea. Benthic diatoms were collected from the sandy sediments to clarify the taxonomic accounts and distribution of the old genus Navicula, i.e., the naviculoid flora. Total 92 taxa belonging to Navicula sensu stricto and 22 genera separated from Navicula sensu lato are reported with brief descriptions and micrographs, and many species remain unidentified. The genera are ranked by the number of diatom species: Navicula of 33 species and varieties, Fallacia of 17 species, Placoneis of five species, Fogedia and Parlibellus of four species, Austariella, Hippodonta and Petroneis of three species, Cosmioneis, Diadesmis, Luticola, Moreneis and Sellaphora of two species and variety, Berkeleya, Chamaepinnularia, Cocconeiopsis, Diademoides, Dickieia, Eolimna, Geissleria, Haslea, Lyrella and Mayamaea of one species. Through 32 samplings of the 12 areas, the important species were identified Navicula perminuta, N. gregaria, N. torneensis, Fallacia cunoniae, F. litoricola, F. subforcipata, F. tenera. The naviculoid diatoms constitute an average of 27% (range: minimum to maximum, 5-75%, of the benthic diatom assemblages. The diatom assemblages are characterized by the colonizing of a few dominant or frequent species and many occasional or rare species. The dominant species were observed to fluctuate with sampling site and time. Among the reported naviculoid diatoms, 46 taxa are newly reported in Korea.

  11. Soil as levels and bioaccumulation in Suaeda salsa and Phragmites australis wetlands of the Yellow River Estuary, China.

    Science.gov (United States)

    Wang, Junjing; Bai, Junhong; Gao, Zhaoqin; Lu, Qiongqiong; Zhao, Qingqing

    2015-01-01

    Little information is available on As contamination dynamics in the soil-plant systems of wetlands. Total arsenic (As) in soil and plant samples from Suaeda salsa and Phragmites australis wetlands was measured in the Yellow River Estuary (YRE) in summer and autumn of 2007 to investigate the seasonal changes in As concentrations in different wetlands. The results showed that soil As levels greatly exceeded the global and regional background values. As levels in soil and the roots and stems of both types of plants were much higher in summer than in autumn, whereas leaf As showed higher level in autumn. Soil sulfur was the main factor influencing As levels in Suaeda salsa wetlands, whereas soil porosity was the most important factor for Phragmites australis wetlands. The contamination factor (CF) showed moderately to considerably polluted levels of As in both wetland soils. Plant roots and leaves of Suaeda salsa had higher As concentrations and biological concentration factors (BCFs) than stems, while the leaves and stems of Phragmites australis showed higher As levels and BCFs than roots. Compared to Phragmites australis, Suaeda salsa generally showed higher translocation factor (TF), while TF values for both plant species were higher in summer than in autumn. PMID:25685781

  12. 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.

  13. Reproductive cycle of Tagelus plebeius (Mollusca: Bivalvia) in the estuary of the Cachoeira River, Ilhéus, Bahia, Brazil.

    Science.gov (United States)

    Ceuta, L O; Boehs, G

    2012-08-01

    This study characterized the reproductive cycle of the stout razor clam Tagelus plebeius in the estuary of the Cachoeira River, Ilhéus, Bahia, northeastern Brazil. Samples of 20 animals per collection were taken biweekly from August 2005 to August 2006. The 480 specimens were measured on the antero-posterior axis (length) and then removed from the shell. After macroscopic analysis, the gonads were fixed in Davidson's solution, processed by routine histology and stained by Harris hematoxylin and eosin. The gonads of both males and females appeared milky white, without sexual dimorphism. Microscopic analyses indicated a M: F ratio of 1.06: 1 and continuous reproduction of T. plebeius in the region. The period from August to October showed the most intense spawning. This study provides another example of continuous reproduction of bivalves in tropical waters, and because this species is a heavily exploited fishery resource in the region, it draws attention to the need for a management plan aimed at reducing harvests. PMID:22990828

  14. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Ip, Carman C.M. [Department of Civil and Structural Engineering, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong (China); Li Xiangdong [Department of Civil and Structural Engineering, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong (China)]. E-mail: cexdli@polyu.edu.hk; Zhang Gan [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Wai, Onyx W.H. [Department of Civil and Structural Engineering, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong (China); Li, Y.-S. [Department of Civil and Structural Engineering, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong (China)

    2007-05-15

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Gao Xuelu [Key Laboratory of Tropical Marine Environmental Dynamics, South China Sea Institute of Oceanology, CAS, Guangzhou 510301 (China) and Laboratory of Marine Ecosystem and Biogeochemistry, Second Institute of Oceanography, SOA, Hangzhou 310012 (China)]. E-mail: xlgao@scsio.ac.cn; Chen Shaoyong [Key Laboratory of Tropical Marine Environmental Dynamics, South China Sea Institute of Oceanology, CAS, Guangzhou 510301 (China); Xie Xueliang [Shandong Light Industry Engineering School, Qingdao 266112 (China); Long Aimin [Key Laboratory of Tropical Marine Environmental Dynamics, South China Sea Institute of Oceanology, CAS, Guangzhou 510301 (China); Ma Fujun [Key Laboratory of Tropical Marine Environmental Dynamics, South China Sea Institute of Oceanology, CAS, Guangzhou 510301 (China)

    2007-07-15

    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 {mu}g g{sup -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 {mu}g g{sup -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.

  17. 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.

  18. Preliminary assessment of the potential for mangrove oyster cultivation in Piraquê-açu river estuary (Aracruz, ES

    Directory of Open Access Journals (Sweden)

    Luciana Alvarenga

    2006-01-01

    Full Text Available At Piraquê-açu river estuary, Aracruz, ES, the technical viability of Crassostrea rhizophorae cultivation was determined through monthly measures in shell length and weight. Seeds of C. rhizophorae were put in cages and suspended in rafts. Increase in height and weight (flesh and dry of the oysters was measured. During ten months (July/98 to May/99, oyster shell reached an average of 37.6 mm in shell height and 3.0 g in flesh weight (the whole animal. High mortality rates were registered and could be related to the high salinity water and to high predation observed, especially by flatworms Stylochophana divae and snails Cymatium parthenopeum, as well as fouling organisms such as barnacles, Serpulidae polychaetes and seed of the same species.No estuário do Rio Piraquê-açu, município de Aracruz, ES, foi avaliada a viabilidade técnica da implantação do cultivo de ostras Crassostrea rhizophorae em lanternas suspensas numa balsa de cultivo, através da estimativa de crescimento e ganho de peso fresco e seco das ostras. Verificou-se que, durante os dez meses de cultivo (junho/98 a maio/99, as ostras atingiram, em média, 37,6 mm de altura e 3,0 g no peso total. Foi registrada uma alta taxa de mortalidade, que poderia ser atribuída aos altos valores de salinidade na água e também aos predadores observados como planárias Stylochoplana divae e gastrópodos Cymatium parthenopeum, além de incrustantes como cracas, poliquetos Serpulidae e principalmente sementes da própria ostra.

  19. Preliminary assessment of the potential for mangrove oyster cultivation in Piraquê-açu river estuary (Aracruz, ES)

    Scientific Electronic Library Online (English)

    Luciana, Alvarenga; Rosebel Cunha, Nalesso.

    2006-01-01

    Full Text Available No estuário do Rio Piraquê-açu, município de Aracruz, ES, foi avaliada a viabilidade técnica da implantação do cultivo de ostras Crassostrea rhizophorae em lanternas suspensas numa balsa de cultivo, através da estimativa de crescimento e ganho de peso fresco e seco das ostras. Verificou-se que, dura [...] nte os dez meses de cultivo (junho/98 a maio/99), as ostras atingiram, em média, 37,6 mm de altura e 3,0 g no peso total. Foi registrada uma alta taxa de mortalidade, que poderia ser atribuída aos altos valores de salinidade na água e também aos predadores observados como planárias Stylochoplana divae e gastrópodos Cymatium parthenopeum, além de incrustantes como cracas, poliquetos Serpulidae e principalmente sementes da própria ostra. Abstract in english At Piraquê-açu river estuary, Aracruz, ES, the technical viability of Crassostrea rhizophorae cultivation was determined through monthly measures in shell length and weight. Seeds of C. rhizophorae were put in cages and suspended in rafts. Increase in height and weight (flesh and dry) of the oysters [...] was measured. During ten months (July/98 to May/99), oyster shell reached an average of 37.6 mm in shell height and 3.0 g in flesh weight (the whole animal). High mortality rates were registered and could be related to the high salinity water and to high predation observed, especially by flatworms Stylochophana divae and snails Cymatium parthenopeum, as well as fouling organisms such as barnacles, Serpulidae polychaetes and seed of the same species.

  20. 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)

  1. 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)

  2. Exploring the use of caged Nucella lapillus to monitor changes to TBT hotspot areas: a trial in the River Tyne estuary (UK).

    Science.gov (United States)

    Smith, A J; Thain, J E; Barry, J

    2006-08-01

    Caged dogwhelks (Nucella lapillus) and mussels (Mytilus edulis) were placed in situ at sites along the River Tyne (UK) in order to investigate the potential for monitoring any change in tributyltin (TBT) mediated effects. After 6 months the development of imposex was investigated in the dogwhelks and concentrations of TBT were determined in the whole tissues of both species. Sites within the estuary showed a high degree of imposex, whilst those at sites North and South of the estuary mouth exhibited significantly lower induction. Concentrations of TBT measured in the dogwhelk and mussel tissues showed the same pattern. The success of the caging technique, occurrence of imposex at other UK sites and the need for further monitoring at TBT impacted locations in the light of current international controls on the use of TBT-based antifouling paints on sea-going vessels are discussed. PMID:16690115

  3. 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.

    2009-01-01

    primary production (GPP) occurred during the peak discharge period. The Chlorophyll a (Chl a) varied between 4 and 18 mg m sup(-3) that reached maximum levels when river discharge and suspended loads decreased by >75% compared to that during peak period...

  4. Sources of heavy metals in sediments of the Hudson River Estuary

    International Nuclear Information System (INIS)

    Sediments in the Hudson Estuary contain zinc, copper and lead from metal pollutants discharged to the harbor in the New York City area, from dispersed sources of contamination introduced upstream, and from natural weathering processes. The magnitude of the contribution from each of these three sources to particular sites can be estimated on the basis of total metal abundances, relative proportions of several metals, and other sediment properties. The pattern of recent heavy-metal contamination in Hudson sediments closely follows the distribution in sediments of 137Cs which was derived over the past two decades from global fallout and local releases from a commercial nuclear reactor. Several simple empirical corrections related to grain size and mineralogy variations are suggested for comparing heavy-metal contamination levels of sandy continental shelf sediments with fine-grained estuarine and coastal sediments. Iron has little variation in Hudson sediments while manganese is greater in surface sediment of some low-salinity and fresh-water areas than deeper in the sediments, and generally less in the high-salinity area of rapid sediment deposition in New York harbor. Much of the pollutant Cu added to the harbor appears to be rapidly deposited in the sediments. (Auth.)

  5. Biogeochemical budgets for Tapi Estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Bapardekar, M.V; DeSousa, S.N; Zingde, M.D.

    2004-01-01

    The Tapi estuary (21 degrees 10'N, 72 degrees 40'E) is a tidal estuary originating in the Multai Ghats in Madhya Pradesh at an elevation of 752 m. The 720 km long river, after passing through the 3 states of Madhya Pradesh, Maharashtra and Gujarat...

  6. 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.

  7. Processes controlling the seasonal and spatial variations in sulfate profiles in the pore water of the sediments surrounding Qi'ao Island, Pearl River Estuary, Southern China

    Science.gov (United States)

    Wu, Zijun; Zhou, Huaiyang; Ren, Dezhang; Gao, Hang; Li, Jiangtao

    2015-04-01

    Marine sediments are the main sink for seawater sulfate and bacterial sulfate reduction is a major component of the global sulfur cycle. Nevertheless, the factors controlling sulfate reduction in the coastal estuary sediments that undergo spatial and temporal variations are still not fully understood. In this study, we measured the concentrations of SO42-, Cl-, CH4, and DIC, and the ?13C of DIC in the pore water of five sampling stations surrounding the Qi'ao Island, Pearl River Estuary, Southern China during the dry season in November 2011 and during the wet season in May 2012. The results showed that the dilution-mixing of the Pearl River with low-concentration sulfate significantly affects the downcore profiles of the sulfate concentrations in the pore water of these estuary sediments. During the wet season, the dilution-mixing of the layers from the top of the sediments to a depth of 14-18 cm occurred at the different sampling stations. In this layer, the sulfate reduction is not appreciable based on the plot of the pore water Cl- and SO42-. Below the dilution-mixing layers, however, sulfate reduction that is driven by the anaerobic oxidation of methane (AOM) occurs. In our comparison, it appeared that the AOM played more important role in the consumption of the pore water sulfate in May 2012 than in November 2011. Meanwhile, we observed a relatively good correlation (r2=0.64) between the depth of the sulfate-methane interface (SMI) and the sulfate concentration in the pore water of the top sediments in dry season, indicating that the pore water sulfate concentration appears to be a primary controlling factor for the depth of the SMI in this estuary. These results highlight the need for an integrated analysis of the hydrologically driven the variations in the sulfate profiles to improve our understanding of the biogeochemical cycling of C, Fe and S and their budgets in estuarine environments.

  8. Spatial and temporal variations in core- and polar- isoprenoid tetraether lipids along a salinity gradient from the lower Pearl River to its estuary

    Science.gov (United States)

    Jia, C.; Gao, S.; Wang, J. X.; Zhang, C. L.

    2014-12-01

    Isoprenoid glycerol dialkyl glycerol tetraethers (iGDGTs) are major archaeal lipids that widely occur in nature and have been used to study paleo-climate and paleo-environments. Estuaries are a dynamic ecosystem that links or divides terrestrial and marine processes. However, factors controlling changes in iGDGTs in estuaries are poorly known. In this study we performed monthly sampling of sediments between July 2012 and May 2013 at four sites from the lower Pearl River to the estuary. Total lipids were extracted to obtain core- and polar-GDGTs, which were identified and quantified using liquid chromatography-mass spectrometry (LC-MS). The average concentrations of archaeal lipids were highest at the seawater station (C-iGDGTs: 1804.0 ng/g; P-iGDGTs: 986.9 ng/g) and lowest at the brackish water station (C-iGDGTs: 364.1 ng/g; P-iGDGTs: 324.4 ng/g) with C-iGDGTs being more abundant than P-iGDGTs in most samples. The composition of iGDGTs varied widely from station to station, but was generally dominated by GDGT-0 or crenarchaeol in both C- and P-iGDGTs. At the freshwater station in the lower Pearl River, the relative abundance of C- and P-iGDGTs varied from month to month, whereas such temporal changes were much less at stations in the brackish and marine environments. These results suggest that Archaea living in freshwater might be more sensitive to environmental variation. A significant positive correlation (R2>0.80, p<0.01) was found between the ratio of Cren./(Cren.+GDGT-0) or ring index and salinity in both C- and P-iGDGT fractions, indicating that salinity is the most important factor affecting the composition of iGDGTs in the estuary environment.

  9. 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.

  10. Estuarial migration of Atlantic salmon in the River Dee (N. Wales)

    International Nuclear Information System (INIS)

    This report describes work undertaken during the period April 1991 to December 1993 by the Welsh Region of the National Rivers Authority to investigate the behaviour of radio-tagged adult Atlantic salmon (Salmo salar L.) in the Welsh Dee. Partial funding for work in 1992 and 1993 was provided by the Department of Trade and Industry under their Tidal Energy research and development programme. (author)

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

    OpenAIRE

    Ce?bron, Aure?lie; 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 befo...

  12. 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

  13. Scenarios involving future climate and water extraction: ecosystem states in the estuary of Australia's largest river.

    Science.gov (United States)

    Lester, Rebecca E; Fairweather, Peter G; Webster, Ian T; Quin, Rebecca A

    2013-07-01

    Management of natural resources, particularly water, increasingly requires that likely benefits of particular actions (e.g., allocating an environmental flow) are quantified in advance. Therefore, new techniques are required that enable those potential benefits to be objectively compared among competing options for management (e.g., compared to a "do nothing" scenario). Scenario modeling is one method for developing such an objective comparison. We used existing hydrologic, hydrodynamic, and ecosystem response models for a case study location, the Coorong, an inverse estuary in South Australia, to illustrate the potential for such scenario modeling to inform natural resource management. We modeled a set of 12 scenarios that included different levels of water extraction, potential future climate change, and sea-level change, thereby enabling a comparison of the different drivers of possible future reductions in water availability in the Coorong. We discovered that potential future climate change combined with current extraction levels has the capacity to devastate the ecology of the Coorong, but also that much of the degradation could be averted by reducing upstream extractions of water. The inclusion of possible sea-level change had a surprising effect, whereby higher sea levels increased hydrodynamic connectivity between the Coorong's two lagoons. Increased hydrodynamic connectivity limited the occurrence of extremely low water levels and high salinities due to evapoconcentration that were simulated for dry future climates in the absence of sea-level rise. These findings strongly suggest that future ecological degradation in the Coorong is not a foregone conclusion, and that management decisions regarding water allocations upstream will determine the ecological future of this coastal lagoon. PMID:23967570

  14. Flow model of the Hudson River estuary from Albany to New Hamburg, New York

    Science.gov (United States)

    Stedfast, David A.

    1982-01-01

    A one-dimensional transient-flow-simulation model was developed to represent a 76-mile reach of the tidal Hudson River between Albany and New Hamburg, N.Y. The river 's direction of flow reverses four times daily as a result of tidal influence, and this process produces complex current patterns and retards the rate at which the river can flush out pollutants. In the model, the reach studied is treated as two subreaches to incorporate differences in channel conditions and to simplify model calibration. This report provides all stage (water-level) and discharge data that were used to calibrate and verify the model and compares the model results with measured data. The model accurately simulated observed flows, but further calibration based upon additional prototype flow measurements would improve simulation of the flow magnitude and phasing of the tide reversal under low-flow conditions. The model can be used to calculate instantaneous stage, velocity, and discharge for any location in the reach and can also be used to calculate net volume flux between tide reversals. (USGS)

  15. 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).

  16. 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.

  17. Structure of the phytoplankton communities and primary production in the Ob River estuary and over the adjacent Kara Sea shelf

    Science.gov (United States)

    Sukhanova, I. N.; Flint, M. V.; Mosharov, S. A.; Sergeeva, V. M.

    2010-10-01

    The material was collected in the Ob River estuary and over the adjacent shallow Kara Sea shelf between 71°14'0 and 75°33'0N at the end of September 2007. Latitudinal zoning in the phytoplankton distribution was demonstrated; this zoning was determined by the changes in the salinity and concentration of nutrients. Characteristic of the phytocenosis in the southern desalinated zone composed of freshwater species of diatom and green algae were the high population density (1.5 × 106 cells/l), biomass (210 ?gC/l), chlorophyll concentration (4.5 ?g/l), and uniform distribution in the water column. High primary production (˜40 ?gC/l/day) was recorded in the upper 1.5-m layer. The estuarine frontal zone located to the north contained a halocline at a depth of 3-5 m. Freshwater species with low population density (2.5 × 105 cells/l), biomass (24 ?gC/l), and chlorophyll concentration (1.5 ?g/l) dominated above the halocline. Marine diatom algae, dinoflagellates, and autotrophic flagellates formed a considerable part of the phytocenosis below the halocline; the community characteristics were twofold lower as compared with the upper layer. The maximal values of the primary production (˜10 ?gC/l per day) were recorded in the upper 1.5-m layer. The phytocenosis in the seaward zone was formed by marine alga species and was considerably poorer as compared with the frontal zone. The assimilation numbers at the end of the vegetation season in the overall studied area were low, amounting to 0.4-1.0 ?gC/?gChl/h in the upper layer and 0.03-0.1 ?gC/?gChl/h under the pycnocline.

  18. Impacts of potential future sea level rise on the North branch of the Changjiang river estuary: Quantifying the saline water intrusion in the dry season

    OpenAIRE

    Kuang, C. P.; Chen, W.; Gu, J.; Mao, X. D.; Huang, H. C.

    2013-01-01

    The phenomenon of global sea level rise (SLR) is undeniable; the 4th IPCC report summaries that the average rise rate of global is 1.8 mm/y since 1961. It is widely taken for granted that SLR will have a severe impact on saline water intrusion processes in estuarine areas. In this paper, by using a two-dimensional hydrodynamic model (MIKE21) and SLR scenarios of 0.5m, 1m and 2m, the impacts of potential future SLR on the North Branch of the Changjiang River Estuary are evaluated b...

  19. Preliminary assessment of heavy metal levels in Mytella falcata (Bivalvia, Mytilidae) from Bacanga River estuary, São Luis, State of Maranhão, Northeastern Brazil

    OpenAIRE

    Carvalho, G. P.; Cavalcante, P. R. S.; Castro, A. C. L.; Rojas, M. O. A. I.

    2000-01-01

    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 concentratio...

  20. 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.

  1. 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.

    2008-01-01

    in the following dry seasons. Biological productivity was found to be very high during the retrieval period of the monsoon. These initial results suggest that the Godavari estuary ecosystem is different from what we know of its seasonal variability....

  2. Geographic variability in amoeboid protists and other microbial groups in the water column of the lower Hudson River Estuary (New York, USA)

    Science.gov (United States)

    Juhl, Andrew R.; Anderson, O. Roger

    2014-12-01

    In comparison to other groups of planktonic microorganisms, relatively little is known about the role of amoeboid protists (amebas) in planktonic ecosystems. This study describes the first geographic survey of the abundance and biomass of amebas in an estuarine water column. Samples collected in the lower Hudson River Estuary were used to investigate relationships between ameba abundance and biomass and hydrographic variables (temperature, salinity, and turbidity), water depth (surface and near bottom), distance from mid-channel to shore, phytoplankton biomass (chlorophyll fluorescence) and the occurrence of other heterotrophic microbial groups (heterotrophic bacteria, nanoflagellates, and ciliates) in the plankton. Although salinity increased significantly towards the mouth of the estuary, there were no significant differences in the abundance or biomass of any microbial group in surface samples collected at three stations separated by 44 km along the estuary's mid-channel. Peak biomass values for all microbial groups were found at the station closest to shore, however, cross-channel trends in microbial abundance and biomass were not statistically significant. Although ameba abundance and biomass in most samples were low compared to other microbial groups, clear patterns in ameba distribution were nevertheless found. Unlike other microbial groups examined, ameba numbers and biomass greatly increased in near bottom water compared to surface samples. Ameba abundance and biomass (in surface samples) were also strongly related to increasing turbidity. The different relationships of ameba abundance and biomass with turbidity suggest a rising contribution of large amebas in microbial communities of the Hudson estuary when turbidity increases. These results, emphasizing the importance of particle concentration as attachment and feeding surfaces for amebas, will help identify the environmental conditions when amebas are most likely to contribute significantly to estuarine bacterivory and C-flux.

  3. 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.

  4. Polycyclic Aromatic Hydrocarbons in Biota from the Brisbane River Estuary, Australia

    Science.gov (United States)

    Kayal, S.; Connell, D. W.

    1995-05-01

    Six species of aquatic organisms from the Brisbane River estuarine system were sampled and their tissues analysed for polycyclic aromatic hydrocarbons (PAHs). These were the sea mullet, Mugil cephalus, bony bream, Nematolosa come, blue catfish, Arius graffei, mud crab, Scylla serrata, pelican, Pelecanus conspicillatus, and silver gull, Larus novaehollandiae. PAHs in the muscle (fish and birds) and soft (crab) tissue samples were isolated by first hydrolysing these samples and then solvent extraction followed by column chromatography. The compounds were then identified and quantified by gas chromatography and gas chromatography coupled with mass spectrometry. The samples contained low levels of PAHs that ranged in molecular weight from 128 (naphthalene) to 252 (benzo[k]fluoranthene). The highest total PAH level of 195 ng g -1, wet weight, was recorded in mullet samples whereas the blue catfish samples yielded the lowest level of 43 ng g -1. Relative ratios of low molecular weight (?3-rings) compounds to those with high molecular weights (?4-rings) suggested a petroleum related origin for the PAHs detected in the organisms. Results indicated that significant biomagnification of PAHs in the estuarine ecosystem sampled is highly unlikely. Characteristics such as the trophic level and size/age were not significant factors in determining the corresponding tissue PAH levels in the fish and crab species. Tissue lipid content, however, was found to be a primary factor in determining the PAH concentrations in fish species. PAH levels recorded in the samples are comparable to those levels reported from similarly urbanized areas in other geographical locations.

  5. 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.)

  6. 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, 2.2-280ng/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-130ng/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

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

    Directory of Open Access Journals (Sweden)

    O.R. OGRI

    2011-09-01

    Full Text Available 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% of hydrocarbon fraction from water was in sediment, confirming higher concentration in sediment than in water. The sediments contained wide range of parafinic and aromatic fraction. Their levels were generally higher than the standard recommended by the National Department of Petroleum (DPR and Federal Environmental Protection Agency (FEPA. However, the Great Kwa River Estuary (GKRE appeared only moderately contaminated with hydrocarbons but not polluted as at this study. Continuous monitoring was recommended for environmental quality of this marine environment in view of the offshore petroleum industries and the upstream municipal activities that discharge untreated waste into this marine ecosystem.

  8. 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

  9. Concentration, clay mineral composition and Coulter counter size distribution of suspended sediment in the turbidity maximum of the Jiaojiang river estuary, Zhejiang, China

    Science.gov (United States)

    Li, B. G.; Eisma, D.; Xie, Q. Ch.; Kalf, J.; Li, Y.; Xia, X.

    1999-09-01

    Measurements of current velocities, concentrations of suspended matter and Coulter counter size distributions of the suspended matter during the tidal cycle at the surface, at mid-depth and near to the bottom were carried out during spring and neap tide in the Jiaojiang river estuary, Zhejiang, China. The results indicate that a lutocline was present during most of the tidal cycle, except during the highest tides when the suspended-matter concentrations were approximately uniform over the entire water depth. Suspended-matter concentrations showed a relation with maximum flow velocities in the surface water and with increasing flow velocities in the bottom water, with regular deposition and resuspension during the tidal cycle. The clay mineral composition of the suspended matter indicated that most of the suspended matter was supplied by the Chang Jiang river. There was probably also some local supply and local sorting. The suspended-matter particle size, measured with a Coulter counter, became larger (with a larger standard deviation) when the suspended-matter concentration increased, and smaller when the suspended-matter concentration decreased. Size sorting during the tidal cycle indicated deflocculation and reflocculation processes; break-up of about 10 to 20% of the flocs in suspension is sufficient to produce the shift in the Coulter counter size distributions observed. This led to the conclusion that the trend in the smectite concentration in the estuary was the result of local sorting of smectite-containing particles after floc break-up.

  10. Modeling coliform-bacteria concentrations and pH in the salt-wedge reach of the Duwamish River Estuary, King County, Washington

    Science.gov (United States)

    Haushild, W.L.; Prych, Edmund A.

    1976-01-01

    Total- and fecal-coliform bacteria, plus pH, alkalinity, and dissolved inorganic carbon are water-quality parameters that have been added to an existing numerical model of water quality in the salt-wedge reach of the Duwamish River estuary in Washington. The coliform bacteria are modeled using a first-order decay (death) rate, which is a function of the local salinity, temperature, and daily solar radiation. The pH is computed by solving a set of chemical-equilibrium equations for carbonate-bicarbonate buffered aqueous solutions. Concentrations of total- and fecal-coliform bacteria computed by the model for the Duwamish River estuary during June-September 1971 generally agreed with observed concentrations within about 40 and 60 percent, respectively. The computed pH generally agreed with observed pH within about a 0.2 pH unit; however, for one 3-week period the computed pH was about a 0.4 unit lower than the observed pH. (Woodard-USGS)

  11. 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.

  12. MOD_FreeSurf2D: a Surface Fluid Flow Simulation Model for Rivers, Streams, and Shallow Estuaries

    Science.gov (United States)

    Martin, N.; Gorelick, S. M.

    2003-12-01

    The MOD_FreeSurf2D, Modular Free Surface Flow in Two-Dimensions, computer model simulates free surface fluid flow in streams, rivers, and shallow estuaries under the assumptions of a well-mixed water column, a small water depth to width ratio, and a hydrostatic pressure distribution. The dependent variables in the model are free surface elevation, which provides total water depth, and fluid velocity. Primary advantages of MOD_FreeSurf2D relative to other two-dimensional models are a stable and computationally efficient numerical representation and a transparent representation of wetting and drying of the simulation domain. MOD_FreeSurf2D approximates the depth-averaged, shallow water equations with a finite volume, semi-implicit, semi-Lagrangian numerical representation similar to the TRIM method (Casulli, 1990; Casulli and Cheng, 1992; Casulli, 1999). The semi-implicit, semi-Lagrangian approach is computationally efficient because time steps can exceed the Courant-Friedrich-Lewy (CFL) stability criterion without significant accuracy degradation (Robert, 1982; Casulli, 1990). The rectangular, Arakawa C-grid, finite-volume layout allows flooding and drying in response to changing flow conditions without prior channel specification or closed boundary specification. Open boundary conditions available in MOD_FreeSurf2D are specified flux, specified total water depth, specified velocity, radiation free surface, and radiation velocity. MOD_FreeSurf2D requires initial topography, undisturbed water depth, and Manning's roughness coefficient. MOD_FreeSurf2D simulated results are shown to converge to the semi-empirical solution for a simple straight channel case. Two applications demonstrate the accuracy of MOD_FreeSurf2D. The first application is the evolution of water depth in the dambreak-style flume experiment of Bellos et al. (1992). In this case, MOD_FreeSurf2D accurately simulates the changing water depth in the flume during the experiment and models the wetting of the flume below the dam and the drying of the flume above the dam. The second application is simulation of a reach of the Kootenai River, ID studied by Lipscomb et al. (1998). Detailed 3D spatial measurements of water depth and velocity were numerically integrated and compared to the 2D values produced by MOD_FreeSurf2D. Results indicate that MOD_FreeSurf2D accurately simulates depth-averaged velocity and total water depth on the reach scale. Currently, MOD_FreeSurf2D is a fully vectorized set of custom Matlab functions. References: Bellos, C.V., Soulis, J.V., and Sakkas, J.G., 1992, Experimental Investigation of Two-dimensional Dam-break Induced Flows, Journal of Hydraulic Research, v. 20, p. 47-63. Casulli, V., 1999, A Semi-Implicit Finite Difference Method for Non-Hydrostatic, Free-Surface Flows, International Journal for Numerical Methods in Fluids, v. 30, p. 425-440. Casulli, V., 1990, Semi-implicit Finite Difference Methods for the Two-Dimensional Shallow Water Equations, Journal of Computational Physics, v. 86, p. 56-74. Casulli, V. and Cheng, R.T., 1992, Semi-implicit Finite Difference Methods for Three-Dimensional Shallow Water Flow, International Journal for Numerical Methods in Fluids, v. 15, p. 629-648. Lipscomb, S.W., Berenbrock, C., and Doyle, J.D., 1997, Spatial Distribution of Stream Velocities for the Kootenai River Near Bonners Ferry, ID, June 1997. U.S. Geological Survey Open File Report 97-830, 174 p. Robert, A., 1982, A Semi-Lagrangian and Semi-Implicit Numerical Integration Scheme for the Primitive Meteorological Equations, Journal of the Meteorological Society of Japan, v.60, n. 1. p. 319-325.

  13. Estuary Live!

    Science.gov (United States)

    Classrooms and individuals can log on to participate in a real-time field trip to a National Estuary Research Reserve. Ask questions, view live video and still images, and learn about estuaries from experts. Topics range from geology to water quality, estuary plants and animals, and cultural heritage. Includes: references and lesson plans, classroom activities and teachers' guides. Archives of previous years are available, featuring sessions from East, West and Gulf Coast estuaries.

  14. 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.

  15. 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.

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

    Directory of Open Access Journals (Sweden)

    da S Q Bezerra Dandara

    2009-08-01

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

  17. 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.

  18. Ecologia do microfitoplâncton do estuário do rio Igarassu, PE, Brasil Microphytoplankton ecology of the Igarassu river estuary, Pernambuco State, Brazil

    Directory of Open Access Journals (Sweden)

    Bruno Machado Leão

    2008-09-01

    Full Text Available Foram realizadas coletas mensais de outubro/2002 a setembro/2003 em baixa-mar e preamar de um mesmo dia, para estudo da comunidade fitoplanctônica do estuário do rio Igarassu, relacionando-a aos parâmetros abióticos. Foram identificadas 210 espécies, distribuídas em cinco divisões. As Bacillariophyta tiveram maior representatividade, com 146 espécies, seguidas pelas Cyanophyta (26 espécies, Chlorophyta (15 espécies, Euglenophyta (12 espécies e Dinophyta (11 espécies. As espécies dominantes foram Chaetoceros curvisetus Cleve (97,8%, na preamar da estação 02, em abril/2003, Thalassionema nitzschioides Grunow (93,67%, na estação 03, na baixa-mar, em agosto/2003, Microcystis aeruginosa Kützing (88,37%, maio/2003, na baixa-mar da estação 02, Rhizosolenia hebetata (Bailey Gran (87,52%, na estação 03, na preamar de fevereiro/2003 e Thalassiosira rotula Meunier (84,18% na estação 02, durante a preamar do mês de junho/2003. A densidade microfitoplanctônica esteve associada à pluviosidade, tendo ocorrido um florescimento expressivo no fim da período chuvoso e inicio do período de estiagem. A diversidade específica e equitabilidade estiveram diretamente relacionadas à baixa-mar e período de estiagem. A partir da observação dos parâmetros ambientais e da estrutura da comunidade fitoplanctônica verificou-se que existe uma forte influência da água do mar no estuário do rio Igarassu, evidenciada pela presença de espécies neríticas e oceânicas, enquanto que, na época de maior pluviosidade ocorreu à presença dominante da Cyanophyta dulcícola Microcystis aeruginosa Kützing.Studies on the phytoplankton community and its relationship to abiotic parameters were carried out at the Igarassu River estuarine area. Plankton collections were made monthly from October/2002 to September/2003 during low and high tides on the same day. We identified 210 species, distributed in five divisions. Bacillariophyta was the most taxonomically diverse with 146 species, followed by Cyanophyta (26 species, Chlorophyta (15 species, Euglenophyta (12 species and Dinophyta (11 species. The dominant species were Chaetoceros curvisetus Cleve (97.8%, high tide, station 2, April/2003; Thalassionema nitzschioides Grunow (93.67%, low tide, station 3, August/2003; Microcystis aeruginosa Kützing (88.37%, low tide, station 2, May/2003; Rhizosolenia hebetata (Bailey Gran (87.52%, high tide, station 3, February/2003; and Thalassiosira rotula Meunier (84.18% high tide, station 2, June/2003. Microphytoplankton density was related to rainfall, with a bloom at the end of the rainy season. Higher species diversity and evenness were related to low tide and dry season. The phytoplankton community was structured by the marine flux during the dry season in the Igarassu River estuary with the presence of neritic and oceanic species. In the rainy season the community was structured by the freshwater flux, with the dominance of the Cyanophyta Microcystis aeruginosa Kützing.

  19. Ecologia do microfitoplâncton do estuário do rio Igarassu, PE, Brasil / Microphytoplankton ecology of the Igarassu river estuary, Pernambuco State, Brazil

    Scientific Electronic Library Online (English)

    Bruno Machado, Leão; José Zanon de Oliveira, Passavante; Maria da Glória Gonçalves da, Silva-Cunha; Marilene Felipe, Santiago.

    2008-09-01

    Full Text Available Foram realizadas coletas mensais de outubro/2002 a setembro/2003 em baixa-mar e preamar de um mesmo dia, para estudo da comunidade fitoplanctônica do estuário do rio Igarassu, relacionando-a aos parâmetros abióticos. Foram identificadas 210 espécies, distribuídas em cinco divisões. As Bacillariophyt [...] a tiveram maior representatividade, com 146 espécies, seguidas pelas Cyanophyta (26 espécies), Chlorophyta (15 espécies), Euglenophyta (12 espécies) e Dinophyta (11 espécies). As espécies dominantes foram Chaetoceros curvisetus Cleve (97,8%, na preamar da estação 02, em abril/2003), Thalassionema nitzschioides Grunow (93,67%, na estação 03, na baixa-mar, em agosto/2003), Microcystis aeruginosa Kützing (88,37%, maio/2003, na baixa-mar da estação 02), Rhizosolenia hebetata (Bailey) Gran (87,52%, na estação 03, na preamar de fevereiro/2003) e Thalassiosira rotula Meunier (84,18% na estação 02, durante a preamar do mês de junho/2003). A densidade microfitoplanctônica esteve associada à pluviosidade, tendo ocorrido um florescimento expressivo no fim da período chuvoso e inicio do período de estiagem. A diversidade específica e equitabilidade estiveram diretamente relacionadas à baixa-mar e período de estiagem. A partir da observação dos parâmetros ambientais e da estrutura da comunidade fitoplanctônica verificou-se que existe uma forte influência da água do mar no estuário do rio Igarassu, evidenciada pela presença de espécies neríticas e oceânicas, enquanto que, na época de maior pluviosidade ocorreu à presença dominante da Cyanophyta dulcícola Microcystis aeruginosa Kützing. Abstract in english Studies on the phytoplankton community and its relationship to abiotic parameters were carried out at the Igarassu River estuarine area. Plankton collections were made monthly from October/2002 to September/2003 during low and high tides on the same day. We identified 210 species, distributed in fiv [...] e divisions. Bacillariophyta was the most taxonomically diverse with 146 species, followed by Cyanophyta (26 species), Chlorophyta (15 species), Euglenophyta (12 species) and Dinophyta (11 species). The dominant species were Chaetoceros curvisetus Cleve (97.8%, high tide, station 2, April/2003); Thalassionema nitzschioides Grunow (93.67%, low tide, station 3, August/2003); Microcystis aeruginosa Kützing (88.37%, low tide, station 2, May/2003); Rhizosolenia hebetata (Bailey) Gran (87.52%, high tide, station 3, February/2003); and Thalassiosira rotula Meunier (84.18% high tide, station 2, June/2003). Microphytoplankton density was related to rainfall, with a bloom at the end of the rainy season. Higher species diversity and evenness were related to low tide and dry season. The phytoplankton community was structured by the marine flux during the dry season in the Igarassu River estuary with the presence of neritic and oceanic species. In the rainy season the community was structured by the freshwater flux, with the dominance of the Cyanophyta Microcystis aeruginosa Kützing.

  20. One-dimensional numerical modeling of the long-term morphodynamic evolution of a tidally-dominated estuary: The Lower Fly River (Papua New Guinea)

    Science.gov (United States)

    Canestrelli, Alberto; Lanzoni, Stefano; Fagherazzi, Sergio

    2014-03-01

    We use a one-dimensional morphodynamic model to analyze the long-term evolution of the lower reaches of the Fly River, Papua New Guinea, from the Everill Junction to the delta mouth. The model shows how the break in the exponential trend of river width triggers deposition, thus producing a tidal region characterized by a higher bed elevation with respect to the river-dominated one. Numerical simulations indicate that the river attains a dynamic equilibrium configuration in which the amount of sediment entering upstream is flushed seaward. A sensitivity analysis is performed, in which the effect of varying solid discharge, tidal harmonics, and initial conditions is discussed. The model shows that an equilibrium configuration results from a delicate balance between the aggrading effect associated with channel divergence (acting mainly during neap tide and at slack water) and the opposite effect of tidal flushing driven by residual water discharge. A physically meaningful morphodynamic equilibrium occurs only for a small range of values of sediment discharge prescribed at the upstream boundary. In particular, an increase in sediment discharge leads to aggradation, while a decrease triggers extensive scour and a deepening of the estuary.

  1. 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.

  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. Characterizing the parent and alkyl polycyclic aromatic hydrocarbons in the Pearl River Estuary, Daya Bay and northern South China Sea: influence of riverine input.

    Science.gov (United States)

    Yuan, Ke; Wang, Xiaowei; Lin, Li; Zou, Shichun; Li, Yan; Yang, Qingshu; Luan, Tiangang

    2015-04-01

    Distributions of 31 parent polycyclic aromatic hydrocarbons (PAHs) and 29 alkyl PAHs in surface sediments of the Pearl River Estuary (PRE), Daya Bay (DYB) and northern South China Sea (SCS) were examined to study the influence of riverine input. It was found that the contributions of riverine input to sediment PAHs in PRE was much higher than other areas. However, higher proportion of alkyl PAHs and low molecular weight PAHs in DYB and the northern SCS was observed, indicating their different sources. Nevertheless, the sediment PAHs in PRE were heterogeneous and affected by the hydrodynamic conditions. The high molecular weight PAHs were dominant in PRE and enriched in the depositional area of suspended particular matter (SPM). Moreover, the concentration of PAHs in SPM was similar to those in surface sediments and dominated in water columns. Therefore, SPM played a very important role in transportation and distribution of PAHs in PRE. PMID:25618368

  4. Hermaphroditism among dioecious Tagelus plebeius (Lightfoot, 1786) (Mollusca, Psammobiidae) and Iphigenia brasiliana (Lamarck, 1818) (Mollusca, Donacidae) on the Cachoeira River estuary, Ilhéus, Bahia, Brazil.

    Science.gov (United States)

    Ceuta, L O; Boehs, G; Santos, J J B

    2010-02-01

    The samples of Tagelus plebeius and Iphigenia brasiliana were manually collected on the Cachoeira River estuary region (Ilhéus, BA, Brazil) between August 2005 and August 2006, with a periodicity of 15 days, with 20 animals collected/sampled, performing 500 samples from each species. The animals were measured, eviscerated and kept in solution of Davidson and after 24-30 hours, they were transferred to ethanol 70%. The material was processed for routine histology, with paraffin embedding, obtaining 7 microm thick slices, stained with Harris hematoxilin and Eosin (HE). By light microscopy analysis, 2 cases of hermaphroditism (0.4%) in T. plebeius samples and one case (0.2%) in I. brasiliana were registered with predominance of female over male follicles. PMID:20231968

  5. Distribution of trace metals and the benthic foraminiferal assemblage as a characterization of the environment in the north Minjiang River Estuary (Fujian, China).

    Science.gov (United States)

    Li, Tao; Li, Xuejie; Zhong, Hexian; Yang, Chupeng; Sun, Guihua; Luo, Weidong

    2015-01-15

    A study of the total benthic foraminifera was carried out in 173 surficial sediment samples collected from the north Minjiang River Estuary and two bays. Foraminiferal assemblages are dominated by Ammonia tepida and subordinately by Elphidium advenum. Trace metal analyses reveal that the study area is unpolluted to moderately polluted with As, Cr, Cu, Ni, Pb, and Zn. The metal distribution has an affinity with fine-grained sediment. Five metal groups are recognized based on their distribution patterns: (1) As, Cr, Cu, Ga, Ni, V, and Zn, (2) Hg, Pb, and Sb, (3) Ba and Zr, (4) Rb and Y, and (5) Sr. The species-environment relationship showed that the species composition is adversely influenced by Cr, Cu, Ga, Pb, Rb, Zn, and Zr, whereas sand may exert a positive influence on Quinqueloculina. This study supports the adaptability of using benthic foraminifera as bio-monitors of trace metal pollution in marginal marine environments. PMID:25467867

  6. 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.

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. Relationship of photosynthetic carbon fixation with environmental changes in the Jiulong River estuary of the South China Sea, with special reference to the effects of solar UV radiation

    International Nuclear Information System (INIS)

    Highlights: ? C-fixation is the highest in turbidity front, though UV resulted in higher inhibition. ? Increased availability of CO2 appeared to stimulate photosynthetic machinery. ? Osmotic stress made phytoplankton more sensitive to UV. - Abstract: Phytoplankton cells in estuary waters usually experience drastic changes in chemical and physical environments due to mixing of fresh and seawaters. In order to see their photosynthetic performance in such dynamic waters, we measured the photosynthetic carbon fixation by natural phytoplankton assemblages in the Jiulong River estuary of the South China Sea during April 24-26 and July 24-26 of 2008, and investigated its relationship with environmental changes in the presence or the absence of UV radiation. Phytoplankton biomass (Chl a) decreased sharply from the river-mouth to seawards (17.3-2.1 ?g L-1), with the dominant species changed from chlorophytes to diatoms. The photosynthetic rate based on Chl a at noon time under PAR-alone increased from 1.9 ?g C (?g Chl a)-1 L-1 in low salinity zone (SSS -1 L-1 in turbidity front (SSS within 10-20), and then decreased to 2.1 ?g C (?g Chl a)-1 L-1 in mixohaline zone (SSS > 20); accordingly, the carbon fixation per volume of seawater increased from 12.8 to 149 ?g C L-1 h-1, and decreased to 14.3 ?g C L-1 h-1sup>-1 h-1. Solar UVR caused the inhibition of carbon fixation in surface water of all the investigated zones, by 39% in turbidity area and 7-10% in freshwater or mixohaline zones. In the turbidity zone, higher availability of CO2 could have enhanced the photosynthetic performance; while osmotic stress might be responsible for the higher sensitivity of phytoplankton assemblages to solar UV radiation.

  12. Seasonal changes in phytoplankton biomass and dominant species in the Changjiang River Estuary and adjacent seas: General trends based on field survey data 1959-2009

    Science.gov (United States)

    Yang, Shu; Han, Xiurong; Zhang, Chuansong; Sun, Baiye; Wang, Xiulin; Shi, Xiaoyong

    2014-12-01

    The characteristics of seasonal variation in phytoplankton biomass and dominant species in the Changjiang River Estuary and adjacent seas were discussed based on field investigation data from 1959 to 2009. The field data from 1981 to 2004 showed that the Chlorophyll- a concentration in surface seawater was between 0.4 and 8.5 ?g dm-3. The seasonal changes generally presented a bimodal trend, with the biomass peaks occurring in May and August, and Chlorophyll-a concentration was the lowest in winter. Seasonal biomass changes were mainly controlled by temperature and nutrient levels. From the end of autumn to the next early spring, phytoplankton biomass was mainly influenced by temperature, and in other seasons, nutrient level (including the nutrient supply from the terrestrial runoffs) was the major influence factor. Field investigation data from 1959 to 2009 demonstrated that diatoms were the main phytoplankton in this area, and Skeletonema costatum, Pseudo-nitzschia pungens, Coscinodiscus oculus-iridis, Thalassinoema nitzschioides, Paralia sulcata, Chaetoceros lorenzianus, Chaetoceros curvisetus, and Prorocentrum donghaiense Lu were common dominant species. The seasonal variations in major dominant phytoplankton species presented the following trends: 1) Skeletonema (mainly S. costatum) was dominant throughout the year; and 2) seasonal succession trends were Coscinodiscus (spring) ? Chaetoceros (summer and autumn) ? Coscinodiscus (winter). The annual dominance of S. costatum was attributed to its environmental eurytopicity and long standing time in surface waters. The seasonal succession of Coscinodiscus and Chaetoceros was associated with the seasonal variation in water stability and nutrient level in this area. On the other hand, long-term field data also indicated obvious interannual variation of phytoplankton biomass and community structure in the Changjiang River Estuary and adjacent seas: average annual phytoplankton biomass and dinoflagellate proportion both presented increased trends during the 1950s-2000s.

  13. 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 used for paleo sea surface temperature reconstruction. Although increasing evidence shows that TEX86 can be affected by multiple environmental variables, little is known about the additional contribution of TEX86-related GDGTs from other planktonic archaeal groups. In this study, we test the hypothesis that GDGTs potentially derived from MG II Archaea affect TEX86 calculations. Analysis of core (C) and intact polar (IP) GDGTs and 454 sequencing and quantitative PCR (qPCR) targeting MG II were performed on suspended particulate matter (SPM) collected along a salinity gradient from the lower Pearl River, its estuary, and the northern South China Sea. The results showed that the community structure varied along the salinity gradient with MG II as the second dominant group in the mixing water and seawater. qPCR data indicated that the abundance of MG II in the mixing water was four to five orders of magnitudes higher than the fresh water and seawater. The Ring Index of archaeal lipids was notably elevated in the Pearl River estuary, which may be attributed to the additional export of cyclopentane moiety-enhanced GDGTs from MG II in the mixing water. Furthermore, a linear correlation was observed between qPCR of MG II and IP-GDGTs derived from phosphate head groups, suggesting that MG II actively produces GDGTs in the water column. These results show strong evidence that MG II synthesizes GDGTs with more cyclopentane moieties, which may bias TEX86 signal derived from GDGTs of Thaumarchaeota. This study highlights that valid interpretation of TEX86 in the geologic record, particularly in coastal oceans, needs to consider the paleo-community structure of planktonic Archaea.

  14. TRANSIT TIME IN ITAJAÍ-AÇÚ RIVER ESTUARY ESTIMAÇÃO DO TEMPO DE TRÂNSITO DAS ÁGUAS NO ESTUÁRIO DO RIO ITAJAÍ-AÇÚ

    Directory of Open Access Journals (Sweden)

    A. R. ZALESKI

    2003-12-01

    Full Text Available The Itajaí-Açu estuary is classified as a highly stratified and presents most of the time a salt wedge. Considering this characteristic, it was used a box model, based on Knudsen hidrographic teorem, to estimate the salt balance and the transit time of fluvial and marine waters in this estuary. This model enables to verify the steady state of mixture conditions and should not be confused as the mean conditions of the estuary. A positive characteristic of this model is that it needs a small number of parameters such as salinity profiles, the estuary volume and currents data, being the latter estimated from river discharge. Seven days of data were assessed, comprising a half synodical cycle (spring-neap tide. Vertical velocities data, estimated by the model, showed that spring tide condition causes a more effective mixing. It was stated a ratio of content of fluvial water to the content of mixohaline water, which confirmed the early findings of intensification of mixing during spring tide period. The estimation of the transit time of fluvial and marine water in the estuary for medium discharge condition, ~ 215 m3.s-1, were 13.2 and 50.7 hours, respectively. It shows that the marine water spends 3 times more time in the estuary than the fluvial water. O Estuário do rio Itajaí-Açu é um estuário altamente estratificado, e apresenta durante a maior parte do ano uma proeminente cunha salina. Devido a esta característica foi possível aplicar o modelo de caixa, baseado no teorema hidrográfico de Knudsen, para se estimar o balanço salino e o tempo de trânsito das águas fluvial e marinha no estuário. Este modelo possibilita verificar o estado estático das condições de mistura no estuário e não deve ser confundido com as condições médias do estuário. Uma característica positiva deste modelo é o fato dele precisar de um numero pequeno de parâmetros, como perfil de salinidade, volume do estuário e dados de corrente, estes últimos estimados a partir de dados de descarga fluvial. Foram analisados sete dias de dados, compreendendo um ciclo completo de maré (sizígia-quadratura. Dados de velocidade vertical, estimados pelo modelo, mostraram que as condições de maré de sizígia causam um maior grau de mistura. Para confirmar isto foi definido um coeficiente de mistura dado pela razão do conteúdo de água fluvial pelo de água de mistura, o que comprovou tal padrão. Quanto ao tempo de transito, verificou-se que em situações de média descarga, cerca de 215 m3.s-1, o tempo de trânsito da água marinha foi três vezes maior do que o da água fluvial. Os valores estimados foram de 13.2 horas para a água fluvial e 50.7 horas para água marinha.

  15. Biological responses to a resumption in river flow in a freshwater-deprived, permanently open Southern African estuary

    Scientific Electronic Library Online (English)

    Paul D, Vorwerk; P William, Froneman; Angus W, Paterson; Nadine A, Strydom; Alan K, Whitfield.

    2008-10-01

    Full Text Available The Kariega Estuary is a freshwater-deprived system due to numerous impoundments in the catchment. This system has had little or no horizontal salinity gradient over the last 15 years, with hypersaline conditions sometimes predominating in the upper reaches. Following high rainfall events in the cat [...] chment during the spring of 2006, including a flood event (approximate 1:10 year) in August 2006, a series of riverine pulses entered the estuary and a horizontal salinity gradient was established. This study examined the influence of this freshwater pulse on four components of the biota within the estuary, namely the zooplankton, and larval, littoral and demersal fishes. The study demonstrated that in three of these components elevated densities were recorded following the riverine input, with only the littoral fishes retaining an almost constant density. In addition, changes in the relative contributions of the estuarine utilisation classes for all three fish groups examined indicated that freshwater input into these systems positively influences the abundances. This has significant implications for water managers as it demonstrates the importance of an Ecological Reserve (defined as 'the water required to protect the aquatic ecosystems of the water resource') for this system.

  16. 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.

    2010-04-01

    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 by a variety of techniques, including elemental (C and N), stable carbon isotopic (? 13C) composition, as well as molecular-level analyses. Total organic carbon (TOC) content was 1.61±1.20% 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 -25.11‰ to -21.28‰ across the studied area, with a trend of enrichment seaward. The spatial trend in C/N ratios mirrored that of ?13C, with a substantial decrease in C/N ratio from 10.9±1.3 in the Lingdingyang Bay surface sediments to 6.5±0.09 in the outer shelf surface sediments. 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, suggesting that the relative abundance of total carbohydrate was fairly constant in TOC. Total neutral sugars as detected by the nine major monosaccharides (lyxose, rhamnose, ribose, arabinose, fucose, xylose, galactose, mannose, and glucose) yielded between 4.0 and 18.6 mg (100 mg OC)-1 in the same sediments, suggesting that a significant amount of carbohydrates were not neutral aldoses. The bulk organic matter properties, isotopic composition and C/N ratios, combined with molecular-level carbohydrate compositions were used to assess the sources and accumulation of terrestrial organic matter in the Pearl River Estuary and the adjacent northern South China Sea shelf. Results showed a mixture of terrestrial riverine organic carbon with in situ phytoplankton organic carbon in the areas studied. 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. 57±13% for Lingdingyang Bay, 19±2% for the inner shelf, which decreased further to 4.3±0.5% on the outer shelf. The molecular composition of the carbohydrate in surface sediments also suggested that the inner estuary was rich in terrestrial-derived carbohydrates but that the contribution of terrestrial-derived carbohydrates decreased offshore. Terrestrial organic carbon accumulation flux was estimated as 1.37±0.92×1011 g yr-1 in Lingdingyang Bay, which accounted for 37±25% of the terrestrial organic carbon transported to the Bay. The burial efficiency of terrestrial organic matter was markedly lower than that of suspended particulate substance (~71%) suggesting that the riverine POC undergoes significant degradation and replacement during transportation through the estuary.

  17. Reproductive cycle of Tagelus plebeius (Mollusca: Bivalvia) in the estuary of the Cachoeira River, Ilhéus, Bahia, Brazil Ciclo reprodutivo de Tagelus plebeius (Mollusca: Bivalvia) no estuário do Rio Cachoeira, Ilhéus-Bahia, Brasil

    OpenAIRE

    Lo, Ceuta; Boehs, G.

    2012-01-01

    This study characterized the reproductive cycle of the stout razor clam Tagelus plebeius in the estuary of the Cachoeira River, Ilhéus, Bahia, northeastern Brazil. Samples of 20 animals per collection were taken biweekly from August 2005 to August 2006. The 480 specimens were measured on the antero-posterior axis (length) and then removed from the shell. After macroscopic analysis, the gonads were fixed in Davidson's solution, processed by routine histology and stained by Harris hematoxylin ...

  18. Plutonium, cesium and uranium series radionuclides in the Hudson River estuary and other environments. Annual technical progress report, December 1, 1979-November 30, 1980

    International Nuclear Information System (INIS)

    Radionuclide activities were measured in a large number of sediment cores and suspended particle samples throughout the salinity range of the Hudson River estuary. Activities of 137Cs, 134Cs and 60Co determined by gamma spectrometry and 239240Pu and 238Pu determined by alpha spectrometry 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. Measurable amounts of reactor-derived 134Cs and 60Co are found in nearly al sediment samples containing appreciable 137Cs between 15 km upstream of Indian Point and the downstream extent of our sampling about 70 km south of the reactor. Fallout 239240Pu reaching the Hudson appears to be almost completely retained within the systems by particle deposition, while 70 to 90% of the 137Cs derived from both reactor releases and fallout has been exported to the coastal waters in solution. Activity levels of 239240Pu in New York harbor sediments indicate a significant source in addition to suspended particles carried down the Hudson. The most likely cause appears to be transport into the estuary of particles from offshore waters having higher specificrom offshore waters having higher specific activities of 239240Pu. Measurements of fallout 239240Pu in a saline lake with a high carbonate ion concentration yielded water column activities about two orders of magnitude greater than has been found for fallout plutonium in other continental waters, indicating extensive mobility in some natural water environments. Experiments using lake water suggest that carbonate ion may indeed be a critical factor in regulating plutonium solubility and that low molecular weight complexes are primarily responsible for enhanced plutonium solubility

  19. Plutonium, cesium, uranium and thorium series radionuclides in the Hudson River estuary and other environments. Annual technical progress report, December 1, 1983-November 30, 1984

    International Nuclear Information System (INIS)

    Radionuclide activities were measured in sediment cores and suspended particle samples from the Hudson River estuary. Activities of 137Cs, 134Cs, and 60Co, 239 240Pu and 238Pu indicate rapid accumulation in marginal cove areas, and very rapid deposition in the harbor adjacent to New York City, resulting in 239 240Pu accumulations of more than an order of magnitude greater than the fallout delivery rate. Fallout 239 240Pu moving downstream appears to be retained within the system by particle deposition, while more than 50% of the 137Cs derived from both reactor releases and fallout has been exported. Significant movement of dissolved plutonium into the estuary from adjacent coastal waters may be occurring. Depth profiles of radionuclides are not significantly altered by physical mixing processes in areas accumulating particles at greater than 1 cm/yr. Transport of fallout radionuclides appears to have decreased faster than would be calculated from continuous removal from a well-mixed soil reservoir, indicating that sequestering of a substantial portion of the soil fallout burden has occurred in the watershed soils over the past two decades. Measurements of fallout 239 240Pu in a saline lake with a high carbonate ion concentration yielded water column activities two orders of magnitude greater than that found for fallout plutoniueater than that found for fallout plutonium in other continental waters, indicating extensive mobility in some natural water environments. Experiments using lake water suggest that carbonate ions are likely to be important in regulating plutonium solubility in some environments and that low molecular weight complexes are primarily responsible for enhanced plutonium solubility. 45 references, 17 figures, 14 tables

  20. Plutonium, cesium, uranium and thorium series radionuclides in the Hudson River estuary and other environments. Annual technical progress report, 1 December 1984-30 November 1985

    International Nuclear Information System (INIS)

    We have measured radionuclide activities in a large number of sediment cores and suspended particle samples throughout the salinity range of the Hudson River estuary. Activities of 137Cs, 134Cs and 60Co determined by gamma spectrometry and /sup 239,240/Pu and 238Pu determined by alpha spectrometry 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 /sup 239,240/Pu accumulations there more than an order of magnitude greater than the fallout delivery rate. Fallout /sup 239,240/Pu moving downstream in the Hudson appears to be almost completely retained within the system by particle deposition, while more than 50% of the 137Cs derived from both reactor releases and fallout has been exported from the tidal Hudson to coastal waters. Some significant movement of dissolved plutonium into the estuary from the adjacent coastal waters may well be occurring. Depth profiles of radionuclides in Hudson sediments do not appear to be significantly altered by physical mixing processes in the sediment in areas accumulating particles at greater than 1 cm/y. Transport of fallout radionuclides from the drainage basin to the tidal Hudson appears to have decreased much faster than would be calculated from continuous removal from a well-mixed soil reservoir, indicating that sequestering of a substantial portion of the sestering of a substantial portion of the soil fallout burden has occurred in the watershed soils over the past two decades. Activities of 60Co in New York harbor sediments in 1984 averaged considerably higher than in 1979 and 1981, suggesting releases of this nuclide to the Hudson comparable to the first five years of reactor operations. 12 figs., 9 tabs

  1. Diversity of bird communities in southern Hangzhou Bay and the Qiantang River estuary and their responses to reclamation of intertidal mudflats

    Directory of Open Access Journals (Sweden)

    Keyi Jiang

    2013-03-01

    Full Text Available Bird communities were surveyed in southern Hangzhou Bay and the Qiantang River estuary from November 2008 to September 2011. A total of 220 bird species belonging to 16 orders and 52 families were recorded, of which, 173 (78.6% were migrants and 24 were listed as state key protected wildlife grade I or II. The composition and diversity of bird communities in eight habitat types were compared using the G-F index and the Jaccard index. Ninety-five species (43.2% were observed in the ponds located in Cixi Wetland Centre with common reed (Phragmites australis marshes, 93 species (42.3% in the coastal woodland, and 78 species (35.5% in intertidal mudflats and coastal reservoirs. About 82.5% of the Charadriiformes species were recorded in intertidal mudflats; 69.2% of the Anatidae species in coastal reservoirs, and 73.4% of the Passeriformes species in the coastal woodland which provides the breeding habitat for the Ardeidae birds. Compared with intertidal mudflats, the highest value of the Jaccard index was obtained for bird communities in the newly reclaimed but undeveloped areas (0.56, followed by coastal reservoirs (0.34 and ponds located in Cixi Wetland Centre with common reed marshes (0.30. For the whole bird community, the highest value of G-F index was obtained in coastal reservoirs and coastal woodland, whereas the lowest value was recorded in the intertidal mudflats. However, newly reclaimed but undeveloped sites had the highest value of G-F index for the waterbird community, followed by coastal reservoirs and intertidal mudflats. Our results indicate that suitable habitat availability and human disturbance are the main factors influencing the spatial distribution of bird communities in the Hangzhou Bay and the Qiantang River estuary. The most serious human disturbance in this region was found to be coastal reclamation. Thus, diversity of local avian communities in the Hangzhou Bay and the Qiantang River estuary could increase if moderate-intensity reclamation and reasonable land use patterns were practiced. Moderate-intensity reclamation is the mode that maintains an intertidal wetland containing a sufficient width of mudflat and upper intertidal zone as well as other important habitatvariables for shorebirds and other birds. Local governments should take action to protect the natural wetlands while using them reasonably and efficiently. It is necessary to maintain several main high-tide roosting sites with sufficient areas for shorebirds and other waterbirds. Some appropriate management measures such as controlling water level in newly reclaimed but undeveloped areas should be carried out to increase the availability of suitable habitat for waterbirds. A variety of artificial wetlands should also be constructed to provide potential habitats for waterbirds and other birds after large scale coastal reclamation.

  2. Macrofauna del curso inferior y estuario del río Biobío (Chile): cambios asociados a variabilidad estacional del caudal hídrico / Macrofauna of the lower reach and estuary of Biobío river (Chile): changes associated to seasonal changes of the river flow

    Scientific Electronic Library Online (English)

    CARLOS, BERTRÁN; JOSÉ, ARENAS; OSCAR, PARRA.

    2001-06-01

    Full Text Available Uno de los sistemas lóticos chilenos de mayor importancia de acuerdo a su caudal es el río Biobío (ca. 37º S). Su estuario es reducido, especialmente en las épocas de máximo caudal. Con el objetivo de poner a prueba la hipótesis de que en verano la disminución del caudal del río Biobío, determina un [...] a mayor depositación del material particulado fino y que el aumento del caudal en invierno resulta en el lavado y transporte del material depositado hacia el mar, y consecuentemente en una disminución de la macrofauna bentónica, se recolectaron muestras para análisis sedimentológicos y faunísticos en el curso inferior y estuario del río Biobío, durante agosto de 1993 y marzo de 1994. Los análisis sedimentológicos indican que el tamaño medio del sedimento correspondió a arenas gruesas. La depositación del material fino suspendido, que ocurre durante el verano se manifiesta en el mayor porcentaje de finos y materia orgánica durante este período. La macrofauna bentónica estuvo compuesta por 16 taxa en el muestreo de invierno y 42 taxa en el de verano. Durante el invierno, la mayoría de ellas estuvo representada por muy pocos individuos. Durante el verano aumentó la riqueza específica y abundancias totales de la macrofauna. Los taxa más abundantes fueron un Archiannelida indeterminado y el poliqueto Perinereis gualpensis. El aumento del caudal en la época invernal, determina el transporte del material depositado hacia el mar y consecuentemente el arrastre de organismos bentónicos. Aún cuando los valores de abundancia y biomasa de macrofauna durante el verano fueron de un orden de magnitud mayor que en la fase invernal, fueron menores que los citados para otros estuarios del centro-sur de Chile (ca. 39º S). Eso contribuye a confirmar el carácter atípico del estuario del río Biobío, el que debido a sus cambios estacionales de caudal genera cambios significativos en la estructura comunitaria de la macrofauna bentónica Abstract in english The Biobío river (ca. 37º S) is one of the most important Chilean lotic systems with regard to their water flow. Its estuary is reduced, especially during maximum flow. With the purpose of testing the hypothesis that during summer, the decrease of river flow results in a higher deposition of fine pa [...] rticles, and that the increase in river flow during winter results in the washing and transport of deposited particles, and consequently in a decrease of the benthic macrofauna. Sediment samples were collected for sedimentological and faunistical analysis during August 1993 and March 1994. The sedimentological analyses indicate that mean size of sediment corresponded to coarse sands. During summer, the deposition of suspended particles is facilitated by the decrease in the river flow and results in higher percentage of fine particles and organic matter in the sediment. The benthic macrofauna was composed by 16 taxa during winter and 42 taxa during summer. During winter, that macrofauna was represented by just a few individuals. During summer, the species richness and macrofaunal abundances increased. The most abundant taxa were an archiannelid species and the polychaete Perinereis gualpensis. The increase of river flow during winter determines the transport of the deposited material toward the sea and consequently, the washing of benthic organisms. Even though, values of macrofaunal abundance and biomass during summer were about one order of magnitude higher than during winter, they are still lower than those mentioned for other estuaries of south-central Chile (ca. 39º S). That confirms the atypical character of the Biobío river estuary, which due to its seasonal changes, significantly affects the community structure of the benthic macrofauna

  3. Macrofauna del curso inferior y estuario del río Biobío (Chile: cambios asociados a variabilidad estacional del caudal hídrico Macrofauna of the lower reach and estuary of Biobío river (Chile: changes associated to seasonal changes of the river flow

    Directory of Open Access Journals (Sweden)

    CARLOS BERTRÁN

    2001-06-01

    Full Text Available Uno de los sistemas lóticos chilenos de mayor importancia de acuerdo a su caudal es el río Biobío (ca. 37º S. Su estuario es reducido, especialmente en las épocas de máximo caudal. Con el objetivo de poner a prueba la hipótesis de que en verano la disminución del caudal del río Biobío, determina una mayor depositación del material particulado fino y que el aumento del caudal en invierno resulta en el lavado y transporte del material depositado hacia el mar, y consecuentemente en una disminución de la macrofauna bentónica, se recolectaron muestras para análisis sedimentológicos y faunísticos en el curso inferior y estuario del río Biobío, durante agosto de 1993 y marzo de 1994. Los análisis sedimentológicos indican que el tamaño medio del sedimento correspondió a arenas gruesas. La depositación del material fino suspendido, que ocurre durante el verano se manifiesta en el mayor porcentaje de finos y materia orgánica durante este período. La macrofauna bentónica estuvo compuesta por 16 taxa en el muestreo de invierno y 42 taxa en el de verano. Durante el invierno, la mayoría de ellas estuvo representada por muy pocos individuos. Durante el verano aumentó la riqueza específica y abundancias totales de la macrofauna. Los taxa más abundantes fueron un Archiannelida indeterminado y el poliqueto Perinereis gualpensis. El aumento del caudal en la época invernal, determina el transporte del material depositado hacia el mar y consecuentemente el arrastre de organismos bentónicos. Aún cuando los valores de abundancia y biomasa de macrofauna durante el verano fueron de un orden de magnitud mayor que en la fase invernal, fueron menores que los citados para otros estuarios del centro-sur de Chile (ca. 39º S. Eso contribuye a confirmar el carácter atípico del estuario del río Biobío, el que debido a sus cambios estacionales de caudal genera cambios significativos en la estructura comunitaria de la macrofauna bentónicaThe Biobío river (ca. 37º S is one of the most important Chilean lotic systems with regard to their water flow. Its estuary is reduced, especially during maximum flow. With the purpose of testing the hypothesis that during summer, the decrease of river flow results in a higher deposition of fine particles, and that the increase in river flow during winter results in the washing and transport of deposited particles, and consequently in a decrease of the benthic macrofauna. Sediment samples were collected for sedimentological and faunistical analysis during August 1993 and March 1994. The sedimentological analyses indicate that mean size of sediment corresponded to coarse sands. During summer, the deposition of suspended particles is facilitated by the decrease in the river flow and results in higher percentage of fine particles and organic matter in the sediment. The benthic macrofauna was composed by 16 taxa during winter and 42 taxa during summer. During winter, that macrofauna was represented by just a few individuals. During summer, the species richness and macrofaunal abundances increased. The most abundant taxa were an archiannelid species and the polychaete Perinereis gualpensis. The increase of river flow during winter determines the transport of the deposited material toward the sea and consequently, the washing of benthic organisms. Even though, values of macrofaunal abundance and biomass during summer were about one order of magnitude higher than during winter, they are still lower than those mentioned for other estuaries of south-central Chile (ca. 39º S. That confirms the atypical character of the Biobío river estuary, which due to its seasonal changes, significantly affects the community structure of the benthic macrofauna

  4. Sources, transformation and fate of particulate amino acids and hexosamines under varying hydrological regimes in the tropical Wenchang/Wenjiao Rivers and Estuary, Hainan, China

    Science.gov (United States)

    Unger, Daniela; Herbeck, Lucia S.; Li, Min; Bao, Hongyan; Wu, Ying; Zhang, Jing; Jennerjahn, Tim

    2013-04-01

    The small tropical Wenchang and Wenjiao Rivers on the island of Hainan, tropical China, are affected by effluents from municipal sewage, aquaculture and agriculture, and by contrasting hydrological regimes related to monsoon and tropical storms. In order to obtain information on the sources, transformation and fate of organic matter (OM) we investigated the amount and composition of amino acids and hexosamines as well as the carbon isotope composition in suspended particulate matter (SPM) from the Wenchang/Wenjiao Estuary. SPM was collected along the salinity gradient starting from the river sites, along the lagoon-shaped Bamen Bay to coastal waters during four sampling campaigns between 2006 and 2009. SPM concentrations ranged between 4.7 and 58.2 mg L-1. Apart from highest values after heavy rain events in spring and summer, SPM showed little seasonal variation, but increased with salinity. From SPM POC% (1.2-20.9%), C/N (4.9-16.5) and ?13Corg (-31.5 to -19.5‰), the molar composition and content of amino acids and hexosamines (8.2-156.2 mg g-1 dry weight) and by comparison with sediments, mangroves, soils and plants we are able to show that soil-derived material, freshwater and marine plankton were the major sources of suspended OM. High POC and amino acid contents were related to primary production sustained by dissolved nutrients to a large extent stemming from municipal and aquaculture effluents. Factor analysis showed that the suite of biogeochemical parameters measured clearly depict the terrestrial vs. marine origin and the freshness/reactivity of OM. The four groups of samples resulting from cluster analysis were basically related to varying hydrological regimes. With respect to the sources, degradation and fate of particulate OM the major factors were: (i) the year round input of labile, amino acid rich riverine OM matter at the freshwater dominated sites, (ii) high input of degraded soil OM after heavy rains with dispersal throughout the estuary and export to the adjacent coastal area, (iii) significant production of labile marine OM especially during summer inside the bay and the (iv) dominance of refractory marine OM during winter and spring season and in the offshore region. While a major part of the fresh OM fuelled by anthropogenic nutrients appears to be stored or recycled inside the bay, periodic torrential rainfalls can lead to a pulsed export of this OM to the coastal area where it may adversely affect seagrass meadows and coral reefs.

  5. Evaluation of Life History Diversity, Habitat Connectivity, and Survival Benefits Associated with Habitat Restoration Actions in the Lower Columbia River and Estuary, Annual Report 2010

    Energy Technology Data Exchange (ETDEWEB)

    Diefenderfer, Heida L.; Johnson, Gary E.; Sather, Nichole K.; Skalski, J. R.; Dawley, Earl M.; Coleman, Andre M.; Ostrand, Kenneth G.; Hanson, Kyle C.; Woodruff, Dana L.; Donley, Erin E.; Ke, Yinghai; Buenau, Kate E.; Bryson, Amanda J.; Townsend, Richard L.

    2011-10-01

    This report describes the 2010 research conducted under the U.S. Army Corps of Engineers (USACE) project EST-P-09-1, titled Evaluation of Life History Diversity, Habitat Connectivity, and Survival Benefits Associated with Habitat Restoration Actions in the Lower Columbia River and Estuary, and known as the 'Salmon Benefits' study. The primary goal of the study is to establish scientific methods to quantify habitat restoration benefits to listed salmon and trout in the lower Columbia River and estuary (LCRE) in three required areas: habitat connectivity, early life history diversity, and survival (Figure ES.1). The general study approach was to first evaluate the state of the science regarding the ability to quantify benefits to listed salmon and trout from habitat restoration actions in the LCRE in the 2009 project year, and then, if feasible, in subsequent project years to develop quantitative indices of habitat connectivity, early life history diversity, and survival. Based on the 2009 literature review, the following definitions are used in this study. Habitat connectivity is defined as a landscape descriptor concerning the ability of organisms to move among habitat patches, including the spatial arrangement of habitats (structural connectivity) and how the perception and behavior of salmon affect the potential for movement among habitats (functional connectivity). Life history is defined as the combination of traits exhibited by an organism throughout its life cycle, and for the purposes of this investigation, a life history strategy refers to the body size and temporal patterns of estuarine usage exhibited by migrating juvenile salmon. Survival is defined as the probability of fish remaining alive over a defined amount of space and/or time. The objectives of the 4-year study are as follows: (1) develop and test a quantitative index of juvenile salmon habitat connectivity in the LCRE incorporating structural, functional, and hydrologic components; (2) develop and test a quantitative index of the early life history diversity of juvenile salmon in the LCRE; (3) assess and, if feasible, develop and test a quantitative index of the survival benefits of tidal wetland habitat restoration (hydrologic reconnection) in the LCRE; and (4) synthesize the results of investigations into the indices for habitat connectivity, early life history diversity, and survival benefits.

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

    Science.gov (United States)

    Mullaney, John R.

    2013-01-01

    Nutrient concentrations and loads and Escherichia coli (E. coli) densities were studied in 2005 and from 2008 through 2011 in water-quality samples from tributaries of the Niantic River Estuary in southeastern Connecticut. Data from a water-quality survey of the base flow of subbasins in the watershed in June 2005 were used to determine the range of total nitrogen concentrations (0.09 to 2.4 milligrams per liter), instantaneous loads (less than 1 to 62 pounds per day) and the yields of total nitrogen ranging from 0.02 to 11.2 pounds per square mile per day (less than 1 to 7.2 kilograms per hectare per year) from basin segments. Nitrogen yields were positively correlated with the amount of developed land in each subbasin. Stable isotope measurements of nitrate (?15N) and oxygen (?18O) ranged from 3.9 to 9.4 per mil and 0.7 to 4.1 per mil, respectively, indicating that likely sources of nitrate in base flow are soil nitrate and ammonium fertilizers, sewage or animal waste, or a mixture of these sources. Continuous streamflow and monthly water-quality sampling, with additional storm event sampling, were conducted at the three major tributaries (Latimer Brook, Oil Mill Brook, and Stony Brook) of the Niantic River from October 2008 through September 2011. Samples were analyzed for nitrogen and phosphorus constituents and E. coli densities. Total freshwater discharge from these tributaries, which is reduced by upstream withdrawals, ranged from 25.9 to 37.8 million gallons per day. Total nitrogen and phosphorus concentrations generally were low, with the mean values below the U.S. Environmental Protection Agency recommended nutrient concentration values of 0.71 milligram per liter and 0.031 milligram per liter, respectively. Total nitrogen was predominantly in the form of total ammonia plus organic nitrogen at the Oil Mill Brook and Stony Brook sites and in the form of nitrate at Latimer Brook. Annual total nitrogen loads that flowed into the Niantic River estuary from the three major tributaries, calculated with the Load Estimator computer program, ranged from 41,400 to 60,700 pounds, with about 52 to 59 percent of the load as total ammonia plus organic nitrogen. Total phosphorus loads ranged from 1,770 to 3,540 pounds per year. Yields of total nitrogen were highest from Latimer Brook, with the range from the three tributaries between 1,100 and 2,720 pounds per square mile per year. Total phosphorus yields ranged from 52 to 185 pounds per square mile per year. The geometric means of E. coli densities in samples from the three Niantic River tributaries were less than the State of Connecticut water-quality standard of 126 colony-forming units per 100 milliliters; however, individual samples from all three tributaries had densities as high as 2,400 to 2,900 colony-forming units per 100 milliliters. High densities of E. coli were more likely to be present in samples collected during wet weather events.

  7. Eighty-year sedimentary record of heavy metal inputs in the intertidal sediments from the Nanliu River estuary, Beibu Gulf of South China Sea

    International Nuclear Information System (INIS)

    210Pb analysis in the sediment core C11 was used to reconstruct the historical fluxes of Hg, Cu, Pb, Zn, Cd, Cr and As in the Nanliu River estuary during the last ?81 year. The 210Pbxs-derived sedimentation rates, molar C/N ratios, enrichment factors and excess fluxes indicated that the natural inputs prevailed till the early 1990s. When the erosion related to land-use modifications enhanced, it promoted higher accumulation rates of the sedimentary material. In the recent sediments they were found a moderate enrichment of Cd and Hg (maximum 3.5- and 2.8-fold corresponding to the local background levels, respectively) and a slight enrichment of Cr, Zn, As and Pb (maximum 1.3-, 1.3-, 1.3- and 1.2-fold, respectively). The excess metal fluxes also showed a consistently increasing tread since the early 1990s, which could be associated with the intensive use of phosphate fertilizers and the combustion of fossil fuels derived from human activities. - The enrichment factor was successfully used to identify the different sources of heavy metals derived from natural, maricultural and agricultural inputs.

  8. Assessment of trace element contamination in sediment cores from the Pearl River and estuary, South China: geochemical and multivariate analysis approaches.

    Science.gov (United States)

    Yang, Yongqiang; Liu, Zhuli; Chen, Fanrong; Wu, Shijun; Zhang, Ling; Kang, Mingliang; Li, Jie

    2014-12-01

    Twenty-four major and trace elements and the mineralogical composition of four sediment cores along the Pearl River and estuary were analyzed using ICP-AES, ICP-MS, and X-ray diffraction (XRD) to evaluate contamination levels. The dominant minerals were quartz, kaolinite, and illite, followed by montmorillonite and feldspars, while small amounts of halite and calcite were also observed in a few samples. Cluster analysis (CA) and principal component analysis (PCA) were performed to identify the element sources. The highest metal concentrations were found at Huangpu, primarily due to wastewater treatment plant discharge and/or the surreptitious dumping of sludge, and these data differed from those of other sources. Excluding the data from Huangpu, the PCA showed that most elements could be considered as lithogenic; few elements are the combination of lithogenic and anthropogenic sources. An antagonistic relationship between the anthropogenic source metals (K, Ba, Zn, Pb, Cd, Ag, Tl, and U) and marine source metals (Na, Mg, Ti, V, and Ca) was observed. The resulting normalized Al enrichment factor (EF) indicated very high or significant pollution of Cd, Ag, Cu, Zn, Mo, and Pb at Huangpu, which may cause serious environmental effects. Conflicting results between the PCA and EF can be attributed to the background values used, indicating that background values must be selected carefully. PMID:25159811

  9. Length-weight relationship and parasites of Chrysichthys nigrodigitatus in Cross River Estuary Itu local government area Akwa Ibom State, Nigeria

    Directory of Open Access Journals (Sweden)

    Usip Lawrence Patrick Esiest

    2013-08-01

    Full Text Available The study describes the length-weight relationship and helminthes bioload of Chrysichthys nigrodigitatus (Catfish in the Cross river estuary purchased at Ayaedehe, Itu Local Government Area, Akwa Ibom State. A total of four hundred and twenty (420 life specimens of C. nigrodigitatus were collected by local fishing gear between June and November, 2011. Data obtained were statistically analyzed using descriptive and inferential statistics. Results showed that the highest length was obtained in July (100.2cm while the least was obtained in June (15.30cm. The highest weight was 1410g obtained in October while the least was obtained in September (22.10g and there were significant differences in monthly distribution of length and weight (P<0.05 of the specimens. Correction coefficient (r between length and weight of C. nigrodigitatus from June November, 2011 lied between 0.89 and 0.98 representing strong relationship between length and weight, the relationship was found to be linear but in logarithmic form. Generally condition factor, (K values decreased proportionately with the length of the fish. A total of seventy two (72 (17.14% parasite specimens were recovered from the fish, out of which helminthes parasites include a cestode Proteocephalis 9 (12.5% and aspidogastrid trematode, Aspidogastrea africanus 10 (13.89% and Nematodes; Paracamallanus cyathopharynx 34 (47.22% and Contracacum sp. 19 (26.64%. Parasitic worm burden and Intensity of infection low and independent of length and weight.

  10. Assessment of heavy metal pollution in wetland soils from the young and old reclaimed regions in the Pearl River Estuary, South China

    International Nuclear Information System (INIS)

    Soils were sampled in three types of wetlands from the young (A) and old (B) reclaimed regions of the Pearl River Estuary. They were analyzed for total concentrations of heavy metals to investigate their distributions and pollution levels in both regions. Results showed that most heavy metals in ditch and riparian wetlands did not significantly differ from those in reclaimed wetlands in A region, while significantly lower for Cd, Cu, Pb, and Zn in reclaimed wetlands in B region, suggesting higher effects of long-term reclamation. Iron, Cr and Cu were identified as metal pollutants of primary concern and had higher contributions to the total toxic units compared to other metals. Almost all metals exceeded their lowest effect levels and Fe and Cr even exceeded the severe effect levels. Multivariate analysis shows that Fe and Mn are controlled by parent rocks and other metals mainly originate from anthropogenic source. - Research highlights: ? Fe, Cr and Cu have higher contributions to the sum of toxic units. ? More than 75.4% soil samples have moderate toxicity in PRE. ? Heavy metals in typical soil profiles exceed the LEL thresholds. ? Heavy metals (except Fe and Mn) mainly originate from anthropogenic source. ? Long reclamation history can lead to greater heavy metal loss in wetland soils. - The findings of this study reveal higher effects of long-term reclamation on heavy metal pollution of wetland soils and contribute to coastal wetland management in subtrstal wetland management in subtropical regions.

  11. Distribution study of fatty acids (FAs) in sediments of Al-Kabeer Al-Shemali river estuary area using (HPLC) technique

    International Nuclear Information System (INIS)

    Samples of sediments from fife sites of Al-kabeer Al-shemali river estuary area were collected during the period (22/2/2007-7/11/2007). The samples were extracted to determine their content of Fatty acids qualitatively and quantitatively by using ( HPLC) technique for determination resources of organic matter in studied sediments . The total concentrations of (FAs) varied from (0.36-1245.5?g/g dry weight).The saturated fatty acids were dominated in all samples (12.1 - 100 %) of total fatty acids. The levels of polyunsaturated fatty acids (PUFAs) were tested percent (0-18 %) of total fatty acids except one sample from surficial sediments in St3 during 8/8/2007 .while the concentrations of monounsaturated fatty acids (MUFAs) were low (0 -21.6 %) of total fatty acids . We can use the saturated long chain fatty acid (C-22) as terrestrial biomarker. poly unsaturated fatty acid (C18: 2?6) as plankton biomarker and the Mono unsaturated fatty acid (C18 : 1?7) as bacterial biomarker.(author)

  12. Levels and bioaccumulation of organochlorine pesticides (OCPs) and polybrominated diphenyl ethers (PBDEs) in fishes from the Pearl River estuary and Daya Bay, South China

    Energy Technology Data Exchange (ETDEWEB)

    Guo Lingli [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, Guangdong 510640 (China); Qiu Yaowen [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, Guangdong 510640 (China); Key Laboratory of Tropic Marine Environmental Dynamics, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301 (China); Zhang Gan [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, Guangdong 510640 (China)], E-mail: zhanggan@gig.ac.cn; Zheng, Gene J.; Lam, Paul K.S. [Department of Biology and Chemistry, Centre for Coastal Pollution and Conservation, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Li Xiangdong [Department of Civil and Structural Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong (China)

    2008-04-15

    Fifty fish samples were collected from the Pearl River estuary (PRE) and Daya Bay, South China and were analyzed for DDTs, HCHs, chlordanes and polybrominated biphenyl ethers (PBDEs). Except the high concentrations of DDT observed in fishes, the concentrations of HCHs, chlordanes and PBDEs were low when compared to other regions. BDE-47 was the predominant PBDE congener and the BDE-209 concentrations were relatively low, despite its high concentration in surface sediments. The absence of significant increase of DDT, HCH, chlordane and PBDE concentrations towards higher {delta}{sup 15}N values, as well as the lack of a significant correlation (p < 0.1) between log concentrations (lipid normalized) and {delta}{sup 15}N, may indicate a weak biomagnification of these chemicals in the food webs. Good agreement was observed between their concentrations and lipid contents of the organisms. Bioconcentration was suggested to be responsible for the accumulation of OCPs and PBDEs in the lower trophic organisms in the studied subtropical waters. - Bioconcentration was suggested to be responsible for the accumulation of OCPs and PBDEs in the lower trophic organisms of subtropical waters.

  13. Assessment of heavy metal pollution in wetland soils from the young and old reclaimed regions in the Pearl River Estuary, South China

    Energy Technology Data Exchange (ETDEWEB)

    Bai Junhong, E-mail: junhongbai@163.com [State Key Laboratory of Water Environment Stimulation, School of Environment, Beijing Normal University, Beijing 100875 (China); Xiao Rong; Cui Baoshan [State Key Laboratory of Water Environment Stimulation, School of Environment, Beijing Normal University, Beijing 100875 (China); Zhang Kejiang [Department of Civil Engineering, University of Calgary, 2500 University Drive NW, Calgary, Alberta, T2N 1N4 (Canada); Wang Qinggai [Appraisal Center for Environment and Engineering, Ministry of Environmental Protection, Beijing 100012 (China); Liu Xinhui; Gao Haifeng; Huang Laibin [State Key Laboratory of Water Environment Stimulation, School of Environment, Beijing Normal University, Beijing 100875 (China)

    2011-03-15

    Soils were sampled in three types of wetlands from the young (A) and old (B) reclaimed regions of the Pearl River Estuary. They were analyzed for total concentrations of heavy metals to investigate their distributions and pollution levels in both regions. Results showed that most heavy metals in ditch and riparian wetlands did not significantly differ from those in reclaimed wetlands in A region, while significantly lower for Cd, Cu, Pb, and Zn in reclaimed wetlands in B region, suggesting higher effects of long-term reclamation. Iron, Cr and Cu were identified as metal pollutants of primary concern and had higher contributions to the total toxic units compared to other metals. Almost all metals exceeded their lowest effect levels and Fe and Cr even exceeded the severe effect levels. Multivariate analysis shows that Fe and Mn are controlled by parent rocks and other metals mainly originate from anthropogenic source. - Research highlights: > Fe, Cr and Cu have higher contributions to the sum of toxic units. > More than 75.4% soil samples have moderate toxicity in PRE. > Heavy metals in typical soil profiles exceed the LEL thresholds. > Heavy metals (except Fe and Mn) mainly originate from anthropogenic source. > Long reclamation history can lead to greater heavy metal loss in wetland soils. - The findings of this study reveal higher effects of long-term reclamation on heavy metal pollution of wetland soils and contribute to coastal wetland management in subtropical regions.

  14. Bioaccumulation and biomagnification of persistent organic pollutants in Indo-Pacific humpback dolphins (Sousa chinensis) from the Pearl River Estuary, China.

    Science.gov (United States)

    Gui, Duan; Yu, Riqing; He, Xuan; Tu, Qin; Chen, Laiguo; Wu, Yuping

    2014-11-01

    Indo-Pacific humpback dolphins (Sousa chinensis) are apex predators in the Pearl River Estuary waters (PRE) of China. PCBs, DDTs and other organochlorine pesticides (OCPs) (e.g., HCHs, HCB, mirex and dieldrin) were analysed in blubber samples of 45 dolphins and 10 prey fishes of S. chinensis collected from 2004 to 2013 in the PRE region to investigate the bioaccumulation and potential biomagnification of persistent organic pollutants (POPs). DDTs were the most abundant residue in the dolphins, with an average of 6,2700 ng g(-1) wet weight (ww), followed by PCBs (average: 1,790 ng g(-1) ww) and other OCPs including ?HCHs, mirex, endrin, ?chlordanes, HCB, dieldrin, aldrin, heptachlor, and pentachlorobenzene. The concentrations of PCBs and DDTs in male dolphins significantly increased with age and length. In contrast, female dolphins did not show obvious bioaccumulation trends with age and body length, possibly due to the lactational and parturitional transfer of these compounds. Compared with the POP residues in the prey fishes, the concentrations of PCBs, DDTs, and HCHs in the dolphin blubber increased by factors of 99, 212, and 5, respectively, whereas the residue levels of the other OCPs increased 2-185 times, indicating a potentially significant biomagnification in the top predators. The potential biomagnification factors calculated for most POPs were significantly higher than those in the cetacean species from other regions. PMID:25113190

  15. Plutonium, cesium, uranium, and thorium series radionuclides in the Hudson River estuary and other environments. Annual technical progress report, December 1, 1982-November 30, 1983

    International Nuclear Information System (INIS)

    We have measured radionuclide activities in a large number of sediment cores and suspended particle samples throughout the salinity range of the Hudson River estuary. Activities of 137Cs, 134Cs and 60Co determined by gamma spectrometry and 239 240Pu and 238Pu determined by alpha spectrometry 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 239 240Pu accumulations there more than an order of magnitude greater than the fallout delivery rate. Fallout 239 240Pu moving downstream in the Hudson appears to be almost completely retained within the system by particle deposition, while more than 50% of the 137Cs derived from both reactor releases and fallout has been exported from the tidal Hudson to coastal waters. Measurements of fallout 239 240 Pu in a saline lake with a high carbonate ion concentration yielded water column activities about two orders of magnitude greater than has been found for fallout plutonium in other continental waters, indicating extensive mobility in some natural water environments. Experiments using lake water suggest that carbonate ion is likely to be a critical factor in regulating plutonium solubility in some environments and that low molecular weight complexes are primarily responsibl weight complexes are primarily responsible for enhanced plutonium solubility. 5 references

  16. Production of branched tetraether lipids in the lower Pearl River and estuary: effects of extraction methods and impact on bGDGT proxies

    Directory of Open Access Journals (Sweden)

    ChuanlunZhang

    2012-01-01

    Full Text Available Branched glycerol dibiphytanyl glycerol tetraethers (bGDGTs are known as bacterial lipids that occur widely in terrestrial environments, particularly in anaerobic peat bogs and soil. We examined the abundance and distribution of bGDGTs in both core (C and polar (P lipid fractions from the water column and surface sediments in the lower Pearl River (PR and its estuary using two extraction methods (sonication vs. Bligh and Dyer. A number of soil samples in the lower PR drainage basin were also collected and extracted for bGDGTs using the sonication method. The results showed aquatic production of bGDGTs as supported by substantial abundances of P-bGDGTs in the water column and sediment samples. The bGDGT-based proxies (BIT, CBT, and MBT were not affected by the method of extraction when C-bGDGTs were analyzed; in such case, the pHCBT of the sediments reflected the soil pH of the lower PR drainage basin, and the temperature close to the annual mean air temperature in the lower PR basin. On the other hand, the P-bGDGT-derived proxies were inconsistent between the two methods. The P-bGDGTs (particularly those extracted using the sonication method may not be reliable indicators of annual mean air temperatures.

  17. The factors controlling the partitioning of polybrominated diphenyl ethers and polychlorinated biphenyls in the water-column of the Pearl River Estuary in South China

    International Nuclear Information System (INIS)

    Research highlights: ? Seasonal dependence for PBDEs and PCBs in the water of PRE was observed. ? POC plays an important role in determining the partition of both PBDEs and PCBs. ? Observed log KOC were lower for PBDEs but higher for PCB than predicted log KOC. ? A combination of sorption to colloids and adsorption to BC influences the partition. - Abstract: In this study, the distribution and partition of polybrominateddiphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in water from the Pearl River Estuary were investigated. A seasonal dependence for dissolved and particle phase PCB and PBDE levels was observed. A high dissolved phase level occurred in the dry season. The positive correlation between POC content in the particles and phase distribution coefficients (Kp) suggested that POC may play an important role in determining the partition of PBDEs and PCBs. A linear correlation between the observed log KOC and log KOW for PBDEs and PCBs was found with slopes less than one. The observed log KOC values were lower than the predicted log KOC values for PBDEs (except for BDE28). The log KOC values were higher than the predicted values for PCBs. A combination of sorption to colloids (10-98% for PBDEs and less than 25% for PCBs) and adsorption to BC was responsible for this observation.

  18. Fusion of Optical Data and SAR Data for the Estimation of Nitrogen Concentration in Pearl River Estuary Hong Kong Seas, China

    Science.gov (United States)

    Liu, X.; Liu, M.; Wu, L.

    2012-08-01

    The knowledge of nitrogen concentration in the ocean is fundamental for the study of oceanic biogeochemical processes. The objective of this research is to estimate total inorganic nitrogen (TIN) by integrating optical parameters from HJ-1 CCD image and polarization parameters from RADARSAT-2 quad-polarization image. The situ data and HJ-1 CCD, RADARSAT-2 image were acquired from Pearl River Estuary Hong Kong Seas, China in August, 2010. The four sensitive parameters, reflectance of Band 4, NDSI (Normalized Difference Spectral Index), the backscattering coefficient of HV and VH were derived as input variables to assess the TIN. A multiple regression model was established between four input variables and TIN. The result showed that the fusion of optical data and SAR data was proved to be successful in estimating TIN in sea surface, with the correlation coefficient (R2) between measured TIN and predicated TIN of 0.774, and the root mean square error (RMSE) of 0.063. The optical data in combination with SAR data is promising for detecting biochemical component in sea surface.

  19. Pattern recognition and classification of sediments according to their metal content using chemometric tools. A case study: the estuary of Nerbioi-Ibaizabal River (Bilbao, Basque Country).

    Science.gov (United States)

    Fdez-Ortiz de Vallejuelo, Silvia; Arana, Gorka; de Diego, Alberto; Madariaga, Juan Manuel

    2011-11-01

    Chemometrics are increasingly used in environmental monitoring studies, but are still far from being accepted as routine tools by field specialists. The multivariate character of usually highly correlated environmental data recommends the use of advanced chemometrics as part of the analytical methodology in order to get information on the basic structure of data. In this work, we have applied a battery of non-supervised (Principal Component Analysis (PCA)) and supervised (k-Nearest Neighbour (k-NN), Soft Independent Modelling of Class Analogies (SIMCA), Linear Discriminant Analysis (LDA) and Artificial Neural Networks (ANNs)) multivariate techniques on a specific environmental dataset. The dataset consists on the concentration of 14 elements (Al, As, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Sn, V and Zn) in 95 sediments collected at eight different locations of the estuary of the Nerbioi-Ibaizabal River (Bilbao, Basque Country) during 12 sampling campaigns conducted every 3 months between 2005 and 2008. The study aims to present a simple methodology of general applicability which may result in a flexible and practical tool to assess chemical pollution in sediments of a given specific site. PMID:21911242

  20. FEEDING INTERACTION OF THE NON-NATIVE AFRICAN CATFISH (Clarias gariepinus BURCHELL, 1822) IN ITANHÉM RIVER ESTUARY, BAHIA, BRAZIL

    Scientific Electronic Library Online (English)

    Leandro Bonesi, Rabelo; Lucy Satiko Hashimoto, Soares.

    2014-09-01

    Full Text Available Foram analisados 214 estômagos de Clarias gariepinus, Centropomus undecimalis e C. parallelus do rio Itanhém e rio Caravelas, nordeste do Brasil, com a finalidade de investigar o impacto da espécie exótica Clarias gariepinus sobre a trama trófica do Rio Itanhém, tendo como referência a alimentação d [...] as espécies nativas no Rio Caravelas. No Rio Itanhém, os camarões foram mais importantes na alimentação de Clarias gariepinus (55%), enquanto Teleostei (98,1%) foi para C. parallelus. Brachyura compôs 92,8% da dieta de C. parallelus do rio Caravelas, enquanto que para C. undecimalis, Teleostei compôs 72,5%. Não houve sobreposição alimentar em nenhum dos casos estudados. Pelos resultados desse trabalho não foi possível detectar indícios de mudanças na dieta de C. parallelus do Rio Itanhém. Abstract in english A total of 214 stomachs of Clarias gariepinus, Centropomus undecimalis and C. parallelus from the Itanhém and Caravelas Rivers, northeastern Brazil, were analyzed to investigate the impact of the non-native species Clarias gariepinus on the Itanhém River food web as compared to that of the adjacent [...] Caravelas River, where this species has not been registered. In Itanhém River, shrimp was the most important food for C. gariepinus, and Teleostei for C. parallelus. In the Caravelas River, Brachyura was the main food item for C. parallelus, and Teleostei for C. undecimalis. There was no food overlap between the species within or between rivers. There is no evidence, in the results of this study, of changes in the diet of the Centropomus parallelus due to the presence of the non-native species.

  1. Estuary Live!!!

    Science.gov (United States)

    Intended for elementary, middle, and high school students, this electronic estuary excursion, Estuary Live!!!, will take place May 8-12, 2000. Free to participants (but please sign up in advance), the field trip will explore the Rachel Carson Site of the North Carolina National Estuarine Research Reserve, covering four islands and salt marshes off the North Carolina coast. The site features useful educational materials, including a photo-illustrated field guide (of the "ecology, habitats and specific plants and animals found in North Carolina's estuaries"); lesson plans (covering highschool biology, estuary habitats, species interactions, and adaptations and communities); and a series of related links. The interactive field trip will require a java-enabled browser, RealVideo (to see a moving image and hear sound), and/or Chatvideo, to see a moving image, ask questions of the naturalist leading the trip, and receive responses via a chat window. Note that ChatVideo requires Netscape 4.0 or better and will not work with AOL or Internet Explorer, and pages "look best" on a screen with resolution of 800x600. The Estuary Live!!! Website is provided by the North Carolina National Estuarine Research Reserve Program, and The Center for Science, Mathematics and Technology Education at East Carolina University.

  2. Plutonium and cesium radionuclides in the Hudson River Estuary. Annual technical progress report, December 1, 1974--November 30, 1975

    International Nuclear Information System (INIS)

    We have obtained a large set of gravity cores from the Hudson Estuary through much of the ambient salinity range. A number of core sections have been analyzed for 137Cs, 134Cs, 60Co, and 40K by direct gamma counting, and for 239,240Pu by alpha-spectrometry. The distribution of both 137Cs and 239,240Pu indicates rapid accumulation in marginal cove areas and in the harbor region adjacent to New York City. The distribution of both 137Cs and 239,240Pu in the sediments is quite similar in surface sediments, and the trends with depth in cores are also similar. The ratio of sediment 239,240Pu to 137Cs throughout the sampled salinity range (0-20 0/00) approximates that in fallout, except near the nuclear reactor at Indian Point where releases of 137Cs result in a ratio lower (0.004 to 0.008) than typical of fallout (0.015). Measurement amounts of reactor-derived 134Cs, 60Co, and 54Mn are found in nearly all of the samples containing appreciable 137Cs. These samples were between 15 km upstream of Indian Point reactor site and the downstream extent of our sampling, 70 km south of the reactor

  3. Sea level variability in South African estuaries

    Scientific Electronic Library Online (English)

    Eckart H., Schumann.

    Full Text Available Sea level variability in the coastal ocean affects water levels in adjacent estuaries over a wide range of periods and to varying distances landward. An assessment is given here of the responses of a number of South African estuaries, focusing on tidal and subtidal periods where the dominant effects [...] are found and the necessary data are available. Shorter period inputs tend to be limited to mouth regions and require more detailed, higher frequency data. Subtidal fluctuations, in particular those caused by coastal trapped waves, play an important part in the dynamics of estuaries in the Western Cape and Eastern Cape. In many cases their influence dominates tidal oscillations farther upstream, and it is apparent that such fluctuations must be considered in any assessment of estuarine characteristics, and indeed their upstream extent. Nonetheless, it should be emphasised that each estuary has unique properties, and must be assessed individually. Sea level variability changes dramatically north of the Kei Estuary, and particularly off the coast of KwaZulu-Natal. Unfortunately, few measurements were available from these estuaries, but the mouth conditions of the estuaries and the build-up of river flow appear to be important factors in resulting estuary water levels. These results show that using only tidal variations in the sea can result in very misleading conclusions about concurrent water levels in estuaries.

  4. ANALYSIS OF FISHERIES DATA IN ASSOCIATION WITH THE DEVELOPMENT OF MINIMUM FLOWS AND LEVELS FOR THE LOWER SUWANNEE RIVER/ESTUARY

    Science.gov (United States)

    The model determines the impact of freshwater inflow on the diversity of species in the estuary. The very nature of estuaries as "regions of mixing of fresh and salt water", in conjunction with their importance as nursery areas for many commercial and recreational fishery specie...

  5. Distribution and migration pathway of radionuclides in the Ob and Yenisei rivers estuaries and adjacent part of the Kara Sea based on 2003-2005 years investigation data

    International Nuclear Information System (INIS)

    Full text: The modern radioecological situation of the Arctic region is substantially connected with migration of polluting substances (including radionuclides) in system Kara sea-estuaries of the rivers of Ob and Yenisei. Drains of the Siberian rivers, due to possible presence at them of products of activity of the radiochemical enterprises of Urals and Siberia (Mayak Production Association, Krasnoyarsk-26 Mining and Chemical Combine), are, last years, one of the main sources of anthropogenous pollution of the Kara sea. Radioactive elements by river waters are transferred in the Kara sea, passing through a zone of interaction the river-sea, a natural geochemical barrier in which distribution and behavior of chemical elements and their radioactive isotopes can significant changes. The estimation of prevalence and carry of a radio-activity on water area is impossible without taking into account available sources of pollution and data on migration separate radionuclides in the sea environment that is defined by their chemical nature and set of geochemical and hydrophysical parameters in the investigation areas. The received results on horizontal distribution of radionuclides in the top layer of surface sediments testifies to significant influence lithological structure of sediments on a level of concentration separate radionuclides, first of all caesium-137 and plutonium-239,240. Carried out of granulometric analysis the structure of sediments has allowed to receive direct dependence of specific activity radionuclides from percentage of clay fraction in samples. The received dependences in a combination with geological and geochemical characteristics of the top layer of surface sediments have allowed to reveal features of distribution on the cores radiation dangerous radionuclides - caesium-137, strontium-90 and plutonium-239,240 in various water areas on a route the river-sea, including and shallow bays of archipelago Novaya Zemlya. Processing of structures of vertical distribution radionuclides caesium-137 and lead-210 on length of a core have allowed to estimate sedimentation rate of modern sediments for the Arctic basin, and the revealed fluctuations of caesium-137 have enabled to identify the periods of the massed receipt in the past of a radio-activity in the region from Mayak Production Association and Krasnoyarsk-26 Mining and Chemical Combine. Studying of a condition radionuclides and chemical elements in water carry out using a filtration and a ultrafiltration of water samples of great volume a radiochemical method, and also a method membrane fractionation small volume samples of water passing a solution through the cartridge of filters with a decreasing size of pores and final definition of separate elements by a mass-spectrometer method. Suspended matter of the near-bottom seawater contains up to 1-5% of Cs-137 and strontium-90, for zones these sizes can reach 20-40 % This means that the cesium-137 concentration coefficient by suspended matter may be as high as 103 -104 and that suspended load may transport considerable amount of radiocaesium. It was found that more than 50% of Sr-90 and plutonium-239,240 enable to form complexes with dissolved organic matter. This effect is smaller in saline waters. We suppose that this effect is related with the behavior of sulvic acid type organic matter in sea water: Fulvic compounds are typical of river water and near-shore sea water and are low in concentration in the marine waters of high salinity. Obtained data have appeared necessary for long-term forecasting a radioecological situation in water area of Kara sea due to consequences of influence of sources of pollution, including the radiochemical enterprises and places of a burial place of radioactive waste. (author)

  6. As assessment of the flux of radionuclide contamination through the Ob and Yenisei rivers and estuaries to the Kara Sea

    International Nuclear Information System (INIS)

    Recent data indicate that there are potentially large sources of radionuclide contamination on the Ob River system. To quantify the existing radionuclide contamination from a possible catastrophic event data and models have been used to quantify scenarios. Using a compilation of Russian data on the radionuclide contamination, hydrologic data and studies on the sediment transport process a conceptual model has been developed of the Ob system, and a numerical model has been applied to estimate the radionuclide flux to the Kara Sea. The initial results of the river modeling in the Mayak region show how important watershed flow from the marshes are to the hydrologic budget of the area. The preliminary analysis of the sediment flux indicates the need to consider the depositional (storage) regions such as the Asanow Marsh. 31 refs., 5 figs

  7. Determination of volatile, toxic hydrogen phosphides in the sediments of the Elbe river, the Elbe estuaries and the Heligoland Bay

    International Nuclear Information System (INIS)

    The distribution and concentraion of phosphines in the sediments of the Elbe river were determined by selective preparation and analysis. The concentration of phosphines in one kilogram wet sediment was in the range of 0.1 to 57 n g with the bulking, anaerobic mud from harbors having the highest and the sandy, aerobic sediments having the lowest concentrations. Phosphines in fluvial sediments were detected successfully for the first time applying the method described. (orig.)

  8. Influence of tides and winds on fishing techniques and strategies in the Mamanguape River Estuary, Paraíba State, NE Brazil

    Scientific Electronic Library Online (English)

    Dandara M.M., Bezerra; Douglas M., Nascimento; Emmanoela N., Ferreira; Pollyana D., Rocha; José S., Mourão.

    2012-09-01

    Full Text Available Este trabalho foi desenvolvido junto a duas comunidades de pescadores artesanais: Barra de Mamanguape e Tramataia, Nordeste do Brasil. O objetivo foi estudar o conhecimento e a percepção dos pescadores artesanais sobre a classificação das marés e dos ventos bem como as técnicas e estratégias de pesc [...] a. A metodologia empregada envolveu várias técnicas: entrevistas livres, entrevistas semiestruturadas, turnês guiadas e observação direta. Os resultados obtidos junto aos pescadores mostraram a classificação das marés de acordo com as fases lunares em: 'maré de quebramento', 'maré de lançamento', 'maré morta' e 'maré grande', designadas tecnicamente estas últimas como maré de quadratura e maré de sizígia, respectivamente. O vento é também um fator essencial no sucesso da pescaria, eles o classificam de acordo com a direção: Norte, Sul, Leste, Sudeste, Sudoeste, Nordeste, Noroeste. Os dados obtidos nesta pesquisa mostraram que o conhecimento dos pescadores pode ser útil na elaboração de planos de manejo e nos estudos de conservação para este estuário. Abstract in english This work was carried out in two small fishing communities, Barra de Mamanguape and Tramataia, Northeastern Brazil. The aim was to study these traditional fishermen's knowledge and perception about tide and wind classifications, as well as their fishing strategies and techniques. Our research method [...] ology involved various techniques: free interviews and semi-structured ones, guided tours and direct observations. The results obtained show the fishermen's classification of the tides according to the phases of the moon: 'breaking tide', 'flushing tide', 'dead tide' and 'big tide' designated technically these last as neap tide and spring tide, respectively. Wind is also an essential factor for the fishermen to make successful catches, and they classify it according to direction: North, South, East, Southeast, Southwest, Northeast and Northwest. The data show that fishermen's knowledge can also be useful in devising plans for management and conservation studies for this estuary.

  9. Plutonium and cesium radionuclides in the Hudson River estuary. Annual technical progress report, December 1, 1976--November 30, 1977

    Energy Technology Data Exchange (ETDEWEB)

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

    1977-01-01

    We have obtained a large set of sediment cores from the Hudson estuary through much of the ambient salinity range. A number of core sections and samples of suspended particles have been analyzed for /sup 137/Cs, /sup 134/Cs and /sup 60/Co by direct gamma counting, and /sup 239/Pu, /sup 240/Pu, and /sup 238/Pu by alpha spectrometry. The distribution of both /sup 137/Cs and /sup 239/Pu, /sup 240/Pu indicates rapid accumulation in marginal cover areas, and especially in the harbor region adjacent to New York City. The distributions of both /sup 137/Cs and /sup 239/Pu, /sup 240/Pu are similar in surface sediments and with depth in cores, but there are deviations from the fallout ratio due to addition of reactor /sup 137/Cs and loss of /sup 137/Cs from the particle phases at higher salinities. Measureable amounts of reactor-derived /sup 134/Cs and /sup 60/Co are found in nearly all sediment samples containing appreciable /sup 137/Cs, between 15 km upstream of Indian Point and the downstream extent of our sampling, 70 km south of the reactor. Accumulations of /sup 239/Pu, /sup 240/Pu in New York harbor sediments are more than an order of magnitude greater than the fallout delivery rate. The most likely explanation is accumulation of fine particles in the harbor which have been transported from upstream areas of the Hudson. Our evidence so far indicates that Indian Point is probably not a significant source of /sup 239/Pu, /sup 240/Pu or /sup 238/Pu compared with the fallout burden of these nuclides already in the sediments.

  10. Plutonium and cesium radionuclides in the Hudson River estuary. Annual technical progress report, December 1, 1976--November 30, 1977

    International Nuclear Information System (INIS)

    We have obtained a large set of sediment cores from the Hudson estuary through much of the ambient salinity range. A number of core sections and samples of suspended particles have been analyzed for 137Cs, 134Cs and 60Co by direct gamma counting, and 239Pu, 240Pu, and 238Pu by alpha spectrometry. The distribution of both 137Cs and 239Pu, 240Pu indicates rapid accumulation in marginal cover areas, and especially in the harbor region adjacent to New York City. The distributions of both 137Cs and 239Pu, 240Pu are similar in surface sediments and with depth in cores, but there are deviations from the fallout ratio due to addition of reactor 137Cs and loss of 137Cs from the particle phases at higher salinities. Measureable amounts of reactor-derived 134Cs and 60Co are found in nearly all sediment samples containing appreciable 137Cs, between 15 km upstream of Indian Point and the downstream extent of our sampling, 70 km south of the reactor. Accumulations of 239Pu, 240Pu in New York harbor sediments are more than an order of magnitude greater than the fallout delivery rate. The most likely explanation is accumulation of fine particles in the harbor which have been transported from upstream areas of the Hudson. Our evidence so far indicates that Indian Point is probablfar indicates that Indian Point is probably not a significant source of 239Pu, 240Pu or 238Pu compared with the fallout burden of these nuclides already in the sediments

  11. Estuary regime

    International Nuclear Information System (INIS)

    The primary aim of this research into estuary regime is to provide engineers with an improved method of predicting the long term evolutionary effects of major engineering changes in estuaries. Of specific interest to the Department of Trade and Industry's renewable energy R and D programme is the long term impact of tidal energy barrages on estuarine morphology. It is considered that the approach being taken is the most appropriate line to follow in terms of developing an applicable estuary regime predictive capability. As a consequence it is considered that any further regime model development should be complimentary to this approach. In addition to model development there is still an enormous amount of basic research required in examining sediment transport processes within the estuarine environment. Recently developed models for predicting the motion of fluidised mud on inter-tidal and sub-tidal banks, an important process within the estuarine sediment regime, requires specific field data calibration and validation. The impacts of wave action on sediment mobility on estuarine banks is a further area requiring field measurements. It is recommended that the opportunity be taken to obtain a set of measurements at a site following construction of major engineering works to provide data for future verification of a regime model. Possibilities exist, for example, on the Tees Estuary for such measurements. (author)

  12. Ictiofauna associada às raízes de mangue do estuário do Rio Pacoti - CE, Brasil / Fish fauna associated to mangrove roots at the Pacoti River estuary

    Scientific Electronic Library Online (English)

    Frederico Moreira, Osório; Wander Oliveira, Godinho; Tito Monteiro da Cruz, Lotufo.

    2011-03-01

    Full Text Available Margens de estuários com a vegetação de manguezal formam um importante hábitat para peixes, pois são zonas de alimentação, abrigo e berçário. O presente trabalho tem como objetivo caracterizar a ictiofauna associada às raízes de mangue do estuário do Rio Pacoti (CE). Foram realizados 10 censos visua [...] is com duração de 90 minutos cada. Foram feitas 671 avistagens, com densidade média de 0,74 avistagens/minuto. Os indivíduos pertencem a 22 espécies e 18 famílias. Todas as espécies registradas são de origem marinha, apesar das amostragens serem realizadas principalmente no período chuvoso. As famílias que apresentaram um maior número de espécies foram Gerreidae e Lutjanidae. As espécies que apresentaram maior frequência de ocorrência foram Lutjanus alexandrei, Lutjanus jocu e Bathygobius soporator, estando presentes em todos os censos. As duas espécies mais abundantes foram L. alexandrei (48%) e L. jocu (17%). Levando-se em consideração as estimativas de tamanho destas espécies, foi verificado que as raízes de mangue são habitadas principalmente por indivíduos jovens de ambas as espécies, o que leva a supor que estas utilizam tal habitat como área de berçário. Contudo, na estação de coleta com menor complexidade estrutural foi avistado o maior número de indivíduos do gênero Lutjanus, em praticamente todas as faixas de comprimento, o que sugere que no Rio Pacoti a quantidade de raízes pode não influenciar na quantidade de indivíduos abrigados. Aproximadamente 70% das espécies avistadas também ocorrem em ambientes recifais, o que demonstra a existência de fortes conexões entre esses dois ecossistemas. Os resultados encontrados enfatizam a importância do habitat estudado para a conservação da ictiofauna costeira e apontam a necessidade de pesquisas relacionadas principalmente ao recrutamento, padrões reprodutivos e tróficos das duas espécies mais representativas. Abstract in english The mangrove vegetation along the margins of estuaries is an important habitat for fish, serving as feeding, shelter and nursery zones. The present work describes the fish fauna associated to mangrove roots at the Pacoti River estuary. A total of ten visual censuses of 90 minutes each were conducted [...] , yielding the number of 671 fish counted, with an average of 0.74 counts/minute. The fishes were identified pertaining to 22 species from 18 different families. All the studied species are originally marine, although the samples were mainly carried out during the rainy season. Gerreidae and Lutjanidae were the more representative families. The species Lutjanus alexandrei, Lutjanus jocu and Bathygobius soporator were present in all censuses and the first two were also the most abundant, with 48 and 17% of the total counts, respectively. Taking into account size estimations of the fish, it was verified that mangrove roots are inhabited mainly by juveniles of both species, indicating the use of this habitat as a nursery area. However, in the least complex sampling site, specimens of genus Lutjanus were sought in higher quantities, comprinsing all size classes, thus suggesting the abundance of roots in Pacoti River might not influence the abundance of sheltered fishes. Another important observation is that almost 70% of the species present in the mangrove roots are typical of reef habitats, indicating the existence of strong connections between these two ecosystems. The results emphasize the importance of this habitat for ichthyofauna conservation to coastal areas. In addition, studies regarding to fish recruitment, reproductive and trophic patterns are needed, especially to those two main important species described herein.

  13. Variation of particulate organic carbon and its relationship with bio-optical properties during a phytoplankton bloom in the Pearl River estuary

    International Nuclear Information System (INIS)

    Highlights: ? A study about relationship between POC and optical properties during a phytoplankton bloom. ? Empirical algorithms for retrieving POC concentration from optical data were developed. ? Phytoplankton carbon and it's ratio to Chl-a are estimated and discussed. ? Demonstrates that marine optical buoy can be a new platform for monitoring biogeochemical cycle. - Abstract: In this study, variations in the particulate organic carbon (POC) were monitored during a phytoplankton bloom event, and the corresponding changes in bio-optical properties were tracked at one station (114.29oE, 22.06oN) located in the Pearl River estuary. A greater than 10-fold increase in POC (112.29-1173.36 mg m-3) was observed during the bloom, with the chlorophyll a concentration (Chl-a) varying from 0.984 to 25.941 mg m-3. A power law function is used to describe the relationship between POC and Chl-a, and the POC:Chl-a ratio tends to change inversely with Chl-a. Phytoplankton carbon concentration is indirectly estimated using the conceptual model proposed by , and this carbon is found to contribute 47.21% (±10.65%) to total POC. The estimated carbon-to-chlorophyll ratio of phytoplankton in diatom-dominated waters is found to be comparable with results reported in the literature. Empirical algorithms for determining the concentrations of Chl-a and POC were developed based on the relationships of these variables with the blue-to-green variables with the blue-to-green reflectance ratio. With these bio-optical models, the levels of particulate organic carbon and Chl-a could be predicted from the radiometric data measured by a marine optical buoy, which showed much more detailed information about the variability in biogeochemical parameters during this bloom event.

  14. Levels of chromium contamination in the estuary of the Iraja river (Guanabara Bay) and experimental incorporation of 51Cr in barnacles (Balanus sp)

    International Nuclear Information System (INIS)

    Levels were determined of chromium contamination in the estuary of Iraja River, produced by an electroplating industry located 3 km upstream the study area. Uptake-and release kinetics of Cr(VI) and Cr(III) in barnacles (Balanus sp.) were studied. Samples of barnacles and suspended particles from Guanabara Bay were analysed. Chromium concentrations (dry weight) ranged from not detectable (ND) to 154,66 ?g/g for soft tissues and from ND to 423,76 ?g/g for suspended particles. Mean of maximum concentrations of chromium in samples from Guanabara Bay are 3 and 4 times above those of identical samples from control area (Coroa Grande). Soft tissues presented a concentration factor (CF) of 103 related to chromium available in suspended particles. 51Cr(VI) is preferentiably incorparated by soft tissues (biological half life being 100 days). Chromium uptake by Balanus sp from solution is as significant as it is from particulate matter available in sea water from experimental sets. CF for Cr(VI) in soft tissues in laboratory conditions was 102 related to 51Cr present in sea water. Environmental chromium contamination was found to be of the same order of magnitude or above levels reported for other areas subjected to industrial impacts. Barnacles appear to be able to accumulate chromium in soft tissues from the available metal in the environment. Cr(VI) is the critical form, being greatly accumulated in soft tissues of barnacles, that act as a long-term integrator of this metal. For Cr(III), this organism can only be regarded as an instantaneous indicator of environmental contamination of chromium attached to suspended particles. (M.A.)

  15. Historical evolution of hypoxia in the East China Sea off the Changjiang (Yangtze River) estuary for the last ~13,000 years: Evidence from the benthic foraminiferal community

    Science.gov (United States)

    Wang, Feifei; Liu, Jian; Qiu, Jiandong; Wang, Hong

    2014-11-01

    The records of benthic foraminifera and lithology of a 35.60-m-long core in the East China Sea off the Changjiang (Yangtze River) estuary were used to decipher the paleoenvironmental changes over the last 13,000 years. The result suggests three stages of environmental evolution: a littoral environment dominated by tide influence in the period of Younger Dryas (YD) (about 13,000-11,500 cal yr BP), a nearshore to shallow-sea environment in the early-mid Holocene (11,500-4600 cal yr BP), and a shallow-sea environment with significant hypoxia since the last 4600 years. The alternation of the low-oxygen foraminiferal assemblages (LOFA) and oxic foraminiferal assemblages (OFA) suggests a weakening hypoxia condition during 4600-2000 cal yr BP, which may be linked to factors such as the weakening of Taiwan Warm Current (TWC), a stronger East Asian Summer Monsoon (EASM), a moderate water depth with stable sea-level and sufficient supply of terrigenous organic materials. Together with the above mentioned factors, human activities might explain the low-oxygen conditions over the past 400 years. However, the hypoxic process was discontinued during the period of 0.6-0.4 cal ka BP, possibly due to the cold climate during Little Ice Age (LIA), which weakened EASM and reduced Total Solar Irradiance (TSI). This study confirms that the species of Epistominella naraensis, Bolivina spp., Bulimina marginata and Ammonia convexidorsa could be used as indicators for hypoxia while the Quinqueloculina spp. as a sensitive indicator of bottom oxygen levels at the core site.

  16. Plutonium and cesium radionuclides in the Hudson River estuary and other environments. Annual technical progress report, December 1, 1978-November 30, 1979

    International Nuclear Information System (INIS)

    Radionuclide activities were measured in a large number of sediment cores and suspended particle samples throughout the salinity range of the Hudson River estuary. Activities of 137Cs, 134Cs and 60Co determined by gamma spectrometry and 239 240Pu and 238Pu determined by alpha spectrometry 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. General distributions of 137Cs and 239 240Pu are similar in surface sediments and with depth in cores, but there are deviations from the fallout ratio due to addition of reactor 137Cs and loss of 137Cs from the particle phases at higher salinities. Measurable amounts of reactor-derived 134Cs and 60Co are found in nearly all sediment samples containing appreciable 137Cs between 15 km upstream of Indian Point and the downstream of our sampling about 70 km south of the reactor. Accumulations of 239 240Pu in New York harbor sediments are more than an order of magnitude greater than the fallout delivery rate, probably primarily due to the accumulation of fine particles containing fallout plutonium in the harbor which have been transported from upstream areas of the Hudson. Measurements of fallout 239 240Pu in a saline lake with a high ca40Pu in a saline lake with a high carbonate ion concentration yielded water column activities about two orders of magnitude greater than has been found for fallout plutonium in other continental waters, indicating extensive mobility in some natural water environments. Experiments using lake water suggest that carbonate ion may indeed be a critical factor in regulatory plutonium solubility

  17. Plutonium and cesium radionuclides in the Hudson River Estuary and other environments. Annual technical progress report, 1 December 1977--30 November 1978

    International Nuclear Information System (INIS)

    Radionuclide activities were measured in a large number of sediment cores and suspended particle samples throughout the salinity range of the Hudson River estuary. Activities of 137Cs, 134Cs, and 60Co determined by gamma spectrometry and 239,240Pu and 238Pu determined by alpha spectrometry 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. General distributions of 137Cs and 239,240Pu are similar in surface sediments and with depth in cores, but there are deviations from the fallout ratio due to (1) addition of reactor 137Cs and (2) loss of 137Cs from the particle phases at higher salinities. Measurable amounts of reactor-derived 134Cs and 60Co are found in nearly all sediment samples containing appreciable 137Cs between 15 Km upstream of Indian Point and 70 Km south of the reactor. Accumulations of 239,240Pu in New York harbor sediments are more than an order of magnitude greater than the fallout delivery rate. Depth profiles of radionuclides and variations of activities with particle size at low salinities in the Hudson indicate the importance of organic phases, including large flocculent particles greater than 180?, in binding plutonium, and no evidence of significant chemical migratioevidence of significant chemical migration within the sediments. Measurements of water column fallout 239,240Pu in a saline lake with a high carbonate ion concentration yielded activities about two orders of magnitude greater than has been found for fallout plutonium in other continental waters, indicating extensive mobility in some natural water environments

  18. Plutonium, cesium, uranium, and thorium series radionuclides in the Hudson River estuary and other environments. Annual technical progress report, December 1, 1981-November 30, 1982

    International Nuclear Information System (INIS)

    Radionuclide activities were measured in a large number of sediment cores and suspended particle samples throughout the salinity range of the Hudson River estuary. Activities of 137Cs, 134Cs and 60Co determined by gamma spectrometry and 239240Pu and 238Pu determined by alpha spectrometry 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 moving downstream in the Hudson appears to be almost completely retained within the system by particle deposition, while 80 to 90% of the 137Cs derived from both reactor releases and fallout has been exported to the coastal waters in solution. Measurements of fallout 239240Pu in a saline lake with a high carbonate ion concentration yielded water column activities about two orders of magnitude greater than has been found for fallout plutonium in other continental waters, indicating extensive mobility in some natural water environments. Experiments using lake water suggest that carbonate ion is likely to be a critical factor in regulating plutonium solubility in some environments and that low molecular weight complexes are primarily responsible for enhanced pluare primarily responsible for enhanced plutonium solubility. Activities of several other nuclides of interest in radioactive waste management (238U, 234U, 232Th, 230Th, 228Th, 231Pa) were also found to be orders of magnitude greater in high carbonate waters than in other natural waters

  19. Occurrence of pesticides and polychlorinated biphenyls in water of the Nile river at the estuaries of Rosetta and Damiatta branches, north of Delta, Egypt.

    Science.gov (United States)

    Abbassy, M S; Ibrahim, H Z; el-Amayem, M M

    1999-03-01

    A study was conducted from summer 1995 to summer 1997 to assess the seasonal occurrence of pesticide residues and other organic contaminants, polychlorinated biphenyls (PCBs), in water at the estuaries of Rosetta and Damiatta branches of the Nile river. The results indicated that organochlorine compounds (OCs) including HCB, lindane, p,p'-DDE, p,p'DDD, p,p'-DDT, aroclor 1254 and aroclor 1260 were present in all the water samples at concentration levels ranging between 0.195-0.240, 0.286-0.352, 0.035-0.067, 0.019-0.033, 0.024-0.031, 0.390-0.70 and 0.166-0.330 microgram/l, respectively. The levels of these compounds were higher in water of Damiatta branch than those found in water of Rosetta branch. Aldrin, dieldrin and endrin were not detected in all water samples. Only 4 compounds from 36 organophosphorus insecticides, fungicides and s-triazine herbicides tested were detected in water samples collected during summer and autumn seasons from Rosetta branch. The concentration levels of these detected compounds, dimethoate, malathion, captan, and ametryne, ranged from 0.011 to 0.340 microgram/l, respectively. Similar compounds during the same seasons as found in water of Rosetta branch were also detected in water of Damiatta branch except ametryne. The levels of the detected compounds (dimethoate, malathion and captan) ranged between 0.030 and 0.330 microgram/l. The levels of detected organophosphorus insecticides, fungicides and s-triazine herbicides were in the order: dimethoate > malathion > captan > ametryne. PMID:10192956

  20. Nutritive Value of Ethmalosa fimbraita (Clupeidae), Mugil cephalus, (Mugilidae) and Cynoglosuss senegalensis (Cynoglossidae) of the Cross River Estuary, Nigeria, West Africa

    OpenAIRE

    Vivian N. Arazu; Paul J. Udo

    2012-01-01

    The nutritive value and the content of some minerals were investigated in three commercially important marine fish species of the Cross River estuary, Nigeria. The fishes studied using standard procedures as recommended by AOAC were Ethmalosa fimbraita, Mugil cephalus and Cynoglosuss senegalensis. The protein, carbohydrate, fat and moisture contents were 18.50%, 9.63%, 8.70% and 66.50% in E. fimbraita while these results in M. cephalus were 19.75%, 11.75%, 8.60% and 63.66% respectively. Data ...

  1. Bacterioplankton dynamics in the Mondego estuary (Portugal)

    OpenAIRE

    Bacelar-nicolau, P.; Nicolau, L. B.; Marques, J. C.; Morgado, F.; Pastorinho, R.; Azeiteiro, U. M.

    2003-01-01

    In this work, the density of bacterioplankton and environmental parameters were monitored over a 11 month period (July 1999-June 2000), and also during one tidal cycle (15 June 2000), at two sampling stations, in the estuary of River Mondego. These data were treated by multivariate analyses methods in order to identify the key factors that control the dynamics of the bacterioplankton in the estuary. Bacterial dynamics were dominated by temporal gradients (annual seasons and tide-related) and ...

  2. DISTRIBUTIONS AND SOURCES OF ALIPHATIC HYDROCARBONS AND KETONES IN SURFACE SEDIMENTS FROM THE CROSS RIVER ESTUARY, S.E. NIGER DELTA, NIGERIA

    Directory of Open Access Journals (Sweden)

    DANIEL R. OROS

    2010-03-01

    Full Text Available Surface sediments from the Cross River estuary were analyzed for the quantitative determination of aliphatic lipids such as n-alkanes, n-alkanones and unresolved complex mixtures (UCMs of branched and cyclic hydrocarbons. The concentrations of the hydrocarbons, including pristane and phytane, were in the range of 0.02-16.84 mg kg-1 (mean 2.23 ± 2.25 mg kg-1 dry weight. The high standard deviations for the n-alkanes most likely reflect the variation in sediment grain size and differences in quantity and quality of organic matter source input. Carbon preference indices for the full range of n-alkanes varied from 0.81 and 4.0, indicating both biogenic and residual petroleum origins. Some samples exhibit odd-to-even carbon number predominances, indicating an input from terrestrial plant waxes and/or macrophytes, whereas even-to-odd carbon number predominances were observed for other samples and are linked to industrial and/or microbial origins. Different distributions and elution ranges of UCMs were also observed, suggesting varied levels of petroleum contamination. Utilization of the LHC/SHC (long/short ratio, ranging from 0.21-7.49, assisted in the evaluation of dominant trends for terrestrial plant and/or macrophyte-derived versus phytoplankton-derived organic matter inputs; while the parameter, Paq, allowed discrimination of the origin of long-chain n-alkanes and the importance of macrophyte contributions to the river system. Series of n-alkan-2-ones ranging from C15 to C35, with concentrations between 0.10 and 5.62 mg kg-1 (mean 0.82 ± 0.44 mg kg-1 dry weight were identified and are considered to have a common origin from direct incorporation of epicuticular plant waxes on the basis of the regularity in their CPI values (1.19-1.21, odd-to-even. Phytone is thought to be a photo-induced microbial oxidation product from incorporated phytol and/or of direct input from tropical higher plant waxes.

  3. Composition and spatial distribution of the benthic macrofauna in the Cachoeira River estuary, Ilhéus, Bahia, Brazil / Composición y distribución espacial de la macrofauna bentónica en el estuario del Río de Cachoeira, Ilhéus, Bahía, Brasil

    Scientific Electronic Library Online (English)

    Thailla M, Ourives; Alexandra E, Rizzo; Guisla, Boehs.

    2011-04-01

    Full Text Available En este estudio se analizó la composición y la distribución espacial del macrobentos en el estuario del río Cachoeira, Ilhéus, Bahía, Brasil. Las muestras fueron recolectadas cada dos meses desde julio de 2008 a mayo de 2009 en seis estaciones de muestreo. En total, se recogieron 613 individuos pert [...] enecientes a 71 taxa. Los gasterópodos mostraron la mayor riqueza y abundancia, seguidos por los poliquetos. La distribución del macrobentos fue influenciada por la salinidad y los parámetros de sedimentos. En la parte externa del estuario fueron abundantes los microgastrópodos, el bivalvo Donax gemmula y el poliqueto Drilonereis sp. En la desembocadura predominaron gasterópodos carnívoros Olivella minuta y Anachis obesa y pastoreadores Neritina virginea y Littorina ziczac. Predominaron en la zona intermedia el poliqueto Hemipodia californiensis y en el sector interno bivalvos eurihalinos Tellina sp., Anomalocardia brasiliana y Tagelus plebeius y los poliquetos depositívoros Heteromastus filiformes y Capitella cf. capitata. Características de salinidad, sedimentos, y hábitos alimentarios son importantes en la composición y distribución de los organismos en este estuario. Abstract in english We analyzed the composition and spatial distribution of macrobenthos in the Cachoeira River estuary, Ilhéus, Bahia, Brazil. Samples were taken bimonthly from July 2008 to May 2009 at six stations along the estuary. In total, 613 individuals belonging to 71 taxa were collected. Molluscs showed the hi [...] ghest richness and abundance, followed by polychaetes. The spatial distribution of macrobenthos was influenced by salinity and by sediment characteristics. In the outer area microgastropods, the bivalve Donax gemmula, and the polychaete Drilonereis sp., were conspicuous. In the river mouth, the carnivorous gastropods Olivella minuta and Anachis obesa and the algal grazers Neritina virginea and Littorina ziczac predominated. In the middle estuary, there was a predominance of the polychaete Hemipodia californiensis. The euryhaline bivalves Tellina sp., Anomalocardia brasiliana, and Tagelus plebeius and the deposit-feeding polychaetes Heteromastus filiformis and Capitella cf. capitata were predominant in the inner estuary. Salinity, sediment characteristics, and dietary habits were important in the composition and distribution of organisms in this estuary.

  4. Anthropogenic source assessment of 226Ra and 210Pb in a sediment core from the Cubatao River estuary (SE Brazil)

    International Nuclear Information System (INIS)

    A sediment core from an estuarine area receiving drainage from the highly industrialized Cubatao River basin (SE Brazil) showed 226Ra and 210Pb activities up to 80 and 213 Bq kg-1, respectively, which are greater than activities considered as regional background levels. Radionuclides and the elevated phosphorus concentrations (up to 0.3% sediment dry weight) found along the sediment core were significantly correlated with each other, indicating source similarity. These results indicate that 226Ra and 210Pb activities are affected by fertilizer industry-derived inputs in addition to natural sources. This interpretation was supported by 210Pb/226Ra ratios (found to be between 2.6 and 3.9) that indicate disequilibrium between 226Ra and its decay product 210Pb, as expected for phosphogypsum-affected sediments. (author)

  5. Seasonal stratification and property distributions in a tropical estuary (Cochin estuary, west coast, India

    Directory of Open Access Journals (Sweden)

    A. Shivaprasad

    2012-07-01

    Full Text Available The intratidal, spring-neap and seasonal variations in stratification were examined in Cochin estuary. The observations established a strong connection with the distribution of chemical and biological properties. The influence of tides and river discharge forcing in water column stability was quantified using potential energy anomaly (PEA and stratification parameter. Partially mixed (neap and well-mixed (spring conditions during low river discharge (dry period were altered in monsoon by the salt wedge intrusions. The ecological impact of salt wedge propagation on high tides bringing upwelled water to the system was evident from the bottom hypoxic, high chlorophyll a and nutrient-rich conditions. Phosphate and nitrite concentrations were higher at the bottom saline conditions but silicate and nitrate were clearly supplied by river water. However, during ebb tide this front was driven out of the estuary. The periodic advance and retreat of the salt wedge was inevitable in making the system immune from extended hypoxia/anoxia and maintaining the health of 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. During monsoon, the intense flushing and reduction in salinity field expansion seemed to be responsible for the limited chlorophyll a levels along the surface of Cochin estuary.

  6. Reproductive cycle of Anomalocardia brasiliana (Mollusca: Bivalvia: Veneridae) in the estuary of the Cachoeira River, Ilhéus, Bahia.

    Science.gov (United States)

    Luz, J R; Boehs, G

    2011-08-01

    The aim of this study was to characterize the reproductive cycle of Anomalocardia brasiliana, typical of the estuarine region of the Cachoeira River, Ilhéus, Bahia, Brazil. For this purpose, 20 specimens were collected biweekly between August 2005 and August 2006 on an intertidal bank (14º 48' 23" S and 39º 02' 47" W). The animals were measured on the anteroposterior axis (length), examined macroscopically and removed from the shell and fixed in Davidson's solution. Subsequently, the tissues were impregnated in paraffin, cut into 7 mm sections and stained with Harris hematoxylin and eosin (HE). The slides were examined under a light microscope. The water temperature at the site ranged from 24 to 30.5 ºC (mean: 27.4 ºC; SD ± 1.9), salinity from zero to 23 (mean: 13.7; SD ± 7.5) and rainfall from 28.3 mm to 248.8 mm monthly (yearly mean: 130 mm). The sample (n = 478) showed a sex ratio (M: F) of 1: 1.2 (p < 0.05) and no cases of hermaphroditism. There was no sexual dimorphism. Males and females showed reproductive synchrony. The reproductive cycle was continuous, with releases of gametes mainly in spring, summer and autumn. These results are similar to those found in other regions, but there was no reproductive rest period as reported for populations in higher latitudes. PMID:21881791

  7. Impacts of the construction of the Port of Suape on phytoplankton in the Ipojuca River estuary (Pernambuco-Brazil

    Directory of Open Access Journals (Sweden)

    Koening Maria Luise

    2003-01-01

    Full Text Available In order to address the impact on phytoplankton, sampling was conducted monthly at 4 fixed stations, from April/86 to March/87 at diurnal low and high tide using a plankton net (65 mum mesh size and a 1 L Van Dorn bottle. Among the 133 taxa identified, marine littoral euryhaline species were most common, outranking Gyrosigma balticum (Ehrenberg Rabenhorst, Nitzschia sigma (Kützing Wm. Smith, Licmophora abbreviata Agardh, Climacosphenia moniligera Ehrenberg, Surirella febigerii Lewis, Terpsinoe musica Ehrenberg and Cylindrotheca closterium (Ehrenberg Reiman and Lewis. The port construction caused significant changes to the phytoplankton community with a strong influence of marine species (mainly dinoflagellate because of the opening of the reef near the river mouth in 1983. The shallow depth and hydrodynamic brought many littoral species to the water columm. The community was composed by marine euryhaline and limnetic organisms, influenced by the salinity, rain and tide. Species diversity was high (> 3 bits.cel-1 owing to the high environmental heterogeneity (marine, freshwater and benthic interactions. After the port implantation, a strong decrease occurred in phytoplankton density owing to high loads of suspended matter. Lowest values (121,00 cells.l-1 were registered during rainy season. During dry season, when light intensity was higher, phytoplankton presented highest density ( 1,789,000 cells.l-1.

  8. Salinity influence on soil microbial respiration rate of wetland in the Yangtze River estuary through changing microbial community.

    Science.gov (United States)

    Fei Xi, Xue; Wang, Lei; Jun Hu, Jia; Shu Tang, Yu; Hu, Yu; Hua Fu, Xiao; Sun, Ying; Fai Tsang, Yiu; Nan Zhang, Yan; Hai Chen, Jin

    2014-12-01

    Estuarine wetland, where freshwater mixes with salt water, comprises different regions (rivers and marine ecosystems) with significantly varying tidal salinities. Two sampling areas, ZXS and JS, were selected to investigate the effect of tidal salinity on soil respiration (SR). ZXS and JS were located in Zhongxia Shoal and Jiangyanan Shoal of Jiuduansha Wetland respectively, with similar elevation and plant species, but significantly different in salinity. The results showed that with almost identical plant biomass, the SR and soil microbial respiration (SMR) of the tidal wetland with lower salinity (JS) were significantly higher than those of the tidal wetland with higher salinity (ZXS) (psoil microbial biomass (SMB) was not significant (p>0.05) with the SMB of ZXS a little higher than that of JS. The higher SMR and SR of JS may be closely connected to the soil microbial community structures and amount of dominant bacteria. Abundant ?- and ?-Proteobacteria and Actinobacteria in JS soil, which have strong heterotrophic metabolic capabilities, could be the main reason for higher SMR and SR, whereas a high number of ?-Proteobacteria in ZXS, some of which have carbon fixation ability, could be responsible for relatively lower carbon output. Path analysis indicated that soil salinity had the maximum negative total influencing coefficient with SMR among the various soil physical and chemical factors, suggesting that higher soil salinity, restricting highly heterotrophic bacteria, is the principle reason for lower SMR and SR in the ZXS. PMID:25499505

  9. Hudson River Sub-Bottom Profile Points

    National Oceanic and Atmospheric Administration, Department of Commerce — Hudson River Estuary Shallow Water Surveys. Subbottom Profile Points. Subbottom data was collected November 5 to December 15, 2009, in the estuary north from...

  10. Nutrient budgets for large Chinese estuaries

    Science.gov (United States)

    Liu, S. M.; Hong, G.-H.; Zhang, J.; Ye, X. W.; Jiang, X. L.

    2009-10-01

    Chinese rivers deliver about 5-10% of global freshwater input and 15-20% of the global continental sediment to the world ocean. We report the riverine fluxes and concentrations of major nutrients (nitrogen, phosphorus, and silicon) in the rivers of the contiguous landmass of China and Korea in the northeast Asia. The rivers are generally enriched with dissolved inorganic nitrogen (DIN) and depleted in dissolved inorganic phosphate (PO43-) with very high DIN: PO43- concentration ratios. DIN, phosphorus, and silicon levels and loads in rivers are mainly affected by agriculture activities and urbanization, anthropogenic activities and adsorption on particulates, and rock types, climate and physical denudation intensity, respectively. Nutrient transports by rivers in the summer are 3-4 times higher than those in the winter with the exception of NH4+. The flux of NH4+ is rather constant throughout the year due to the anthropogenic sources such as the sewer discharge. As nutrient composition has changed in the rivers, ecosystems in estuaries and coastal sea have also changed in recent decades. Among the changes, a shift of limiting nutrients from phosphorus to nitrogen for phytoplankton production with urbanization is noticeable and in some areas silicon becomes the limiting nutrient for diatom productivity. A simple steady-state mass-balance box model was employed to assess nutrient budgets in the estuaries. The major Chinese estuaries export beyond the estuaries is mainly supported by other nutrient sources such as regeneration, open ocean and atmospheric deposition.

  11. Studies of anoxiC conditions in Framvaren fjord, Gullmaren fjord and Byfjorden and of mixing between seawater and freshwater at the Kalix river and estuary

    International Nuclear Information System (INIS)

    The sediments in the anoxic Framvaren fjord acts as a source for actinides to the overlaying water column. The remobilisation process is most likely linked to early diagenetic alteration of the marine organic material in the sediments. This is indicated by the close correlation between Pu, Am and dissolved organic carbon depth profiles in the water column. Speciation studies of the plutonium and americium in the water column shows that both to a large degree are associated to colloidal material in the size range 0.01-0.45 ?m. Less than 2% is retained by a 0.45 ?m filter which is reflected in the low KD-values obtained of about 20 000, which is at least a factor of 10 lower than in typical coastal waters. It is also proven that the plutonium exist almost entirely in the trivalent state in the anoxic water column. This study is the first ever to show extensive remobilisation of plutonium and americium from sediments in anoxic marine basins. Similar remobilisation from sediments most likely occur in other anoxic marine waters where early diagenesis results in humic and fulvic acid production. Although the remobilised actinides in the Framvaren fjord at present don't pose any radiological hazard due to the lack of fish in anoxic waters, it is of great concern to identify processes involved in the remobilisation of actinides from anoxic sediments as such sediments likely will be a major source for actinides in the Baltic Sea and other oxygen sensitive basins in the long term perspective. In such basins the remobilised plutonium may reach oxygenated and biological productive waters by convection. Results from the temporarily oxygen deficient Gullmaren fjord on the Swedish west coast shows that remobilisation from sediments can not be identified during short (a few months) periods of oxygen deficient water. The rapid bioturbation (quantified by tracer studies) in this fjord results in that sedimenting organic material rapidly is buried and distributed within the upper 10-15 cm of sediments. This means that the organic material is diluted with large amounts of inorganic material which may act as traps for the mobilised actinides. It is likely that anoxic conditions must persist for a long enough time to allow organic rich sediment to accumulate in sufficient amounts before substantial amount of humics are produced that may mobilise the actinides. This time depends on the organic matter flux to the sediments. Laminated sediments and suspended matter collected in the estuary of the Kalix river shows that the input of plutonium to the Baltic Sea from river run-off at present is of rather small importance but may in the long term perspective become one of the more important sources as the residence time of plutonium in the the Baltic Sea water column is much shorter than the residence time in the river drainage basins. Drainage basins containing large percentage of mire and wetland will be of particular importance. (EHS, LN)

  12. Distribution of polycyclic aromatic hydrocarbons (PAHs) in rivers and estuaries in Malaysia: a widespread input of petrogenic PAHs.

    Science.gov (United States)

    Zakaria, Mohamad Pauzi; Takada, Hideshige; Tsutsumi, Shinobu; Ohno, Kei; Yamada, Junya; Kouno, Eriko; Kumata, Hidetoshi

    2002-05-01

    This is the first publication on the distribution and sources of polycyclic aromatic hydrocarbons (PAHs) in riverine and coastal sediments in South East Asia where the rapid transfer of land-based pollutants into aquatic environments by heavy rainfall and runoff waters is of great concern. Twenty-nine Malaysian riverine and coastal sediments were analyzed for PAHs (3-7 rings) by gas chromatography mass spectrometry. Total PAHs concentrations in the sediment ranged from 4 to 924 ng/g. Alkylated homologues were abundant for all sediment samples. The ratio of the sum of methylphenanthrenes to phenanthrene (MP/P), an index of petrogenic PAHs contribution, was more than unity for 26 sediment samples and more than 3 for seven samples for urban rivers covering a broad range of locations. The MP/P ratio showed a strong correlation with the total PAHs concentrations, with an r2 value of 0.74. This ratio and all other compositional features indicated that Malaysian urban sediments are heavily impacted by petrogenic PAHs. This finding is in contrast to other studies reported in many industrialized countries where PAHs are mostly of pyrogenic origin. The MP/P ratio was also significantly correlated with higher molecular weight PAHs such as benzo[a]pyrene, suggesting unique PAHs source in Malaysia which contains both petrogenic PAHs and pyrogenic PAHs. PAHs and hopanes fingerprints indicated that used crankcase oil is one of the major contributors of the sedimentary PAHs. Two major routes of inputs to aquatic environments have been identified: (1) spillage and dumping of waste crankcase oil and (2) leakage of crankcase oils from vehicles onto road surfaces, with the subsequent washout by street runoff. N-Cyclohexyl-2-benzothiazolamine (NCBA), a molecular marker of street dust, was detected in the polluted sediments. NCBA and other biomarker profiles confirmed our hypothesis of the input from street dust contained the leaked crankcase oil. The fingerprints excluded crude oil, fresh lubricating oil, asphalt, and tire-particles as major contributors. PMID:12026970

  13. Community structure of the ichthyofauna associated with seagrass beds ( Halodule wrightii) in Formoso River estuary - Pernambuco, Brazil

    Scientific Electronic Library Online (English)

    Pedro H.C., Pereira; Beatrice P., Ferreira; Sérgio M., Rezende.

    2010-09-01

    Full Text Available Pradarias de fanerógamas são utilizadas pela ictiofauna, de maneira geral como ambiente de berçário, abrigo contra predadores, diminuição de competição em aior disponibilidade de recursos alimentares, estabelecendo uma relação de conectividade com demais ecossistemas costeiros. No presente estudo fo [...] i avaliada a estrutura da ictiofauna associada às pradarias de fanerógamas do estuário do Rio Formoso no litoral de Pernambuco durante o inverno de 2008. Foram realizados no total 27 arrastos manuais (15 diurnos e 12 noturnos), nos quais foram amostrados 358 peixes pertencentes a 18 famílias, 21 gêneros e 25 espécies. A Captura por unidade de esforço (CPUE) média por arrasto foi de 13,5 indivíduos e 4,95 espécies por arrasto. As famílias mais abundantes foram Scaridae (n = 111), Tetraodontidae (n = 63), Lutjanidae (n = 56), Mullidae (n = 39) e Engraulidae (n = 19). Analisando os índices ecológicos, observou-se que os mesmos foram sempre maiores para o período da noite, confirmando o fato do uso de tais áreas pela ictiofauna de forma mais intensa neste período. A necessidade de medidas para proteção destas áreas é evidente na região devido a sua importância e vulnerabilidade a impactos antrópicos. Abstract in english Seagrass beds are used by juvenile fishes in different ways, generally as nursery sites, shelter from predators, reducing competition and increasing availability of food resources, thus establishing a relationship of connectivity with other ecosystems. In the present study, the community structure o [...] f the ichthyofauna associated with seagrass beds on the Formoso River (Pernambuco - Brazil) was evaluated during the winter of 2008. Twenty-seven manual trawls (15 daytime and 12 nighttime) were performed, and a total of 358 fishes belonging to 18 families, 21 genus and 25 species were collected. The Catch Per Unit Effort (CPUE) by trawling average was 13.5 and 4.95 individuals per species per trawl. The most abundant families were Scaridae (n = 111), Tetraodontidae (n = 63), Lutjanidae (n = 56), Mullidae (n = 39) and Engraulidae (n = 19). Ecological indices for dial changes were always higher for the night period, confirming that such areas are used more frequently during this period. The need for measures to conserve these areas is emphasized, by its importance and vulnerability to human impacts.

  14. Community structure of the ichthyofauna associated with seagrass beds ( Halodule wrightii in Formoso River estuary - Pernambuco, Brazil

    Directory of Open Access Journals (Sweden)

    Pedro H.C. Pereira

    2010-09-01

    Full Text Available Seagrass beds are used by juvenile fishes in different ways, generally as nursery sites, shelter from predators, reducing competition and increasing availability of food resources, thus establishing a relationship of connectivity with other ecosystems. In the present study, the community structure of the ichthyofauna associated with seagrass beds on the Formoso River (Pernambuco - Brazil was evaluated during the winter of 2008. Twenty-seven manual trawls (15 daytime and 12 nighttime were performed, and a total of 358 fishes belonging to 18 families, 21 genus and 25 species were collected. The Catch Per Unit Effort (CPUE by trawling average was 13.5 and 4.95 individuals per species per trawl. The most abundant families were Scaridae (n = 111, Tetraodontidae (n = 63, Lutjanidae (n = 56, Mullidae (n = 39 and Engraulidae (n = 19. Ecological indices for dial changes were always higher for the night period, confirming that such areas are used more frequently during this period. The need for measures to conserve these areas is emphasized, by its importance and vulnerability to human impacts.Pradarias de fanerógamas são utilizadas pela ictiofauna, de maneira geral como ambiente de berçário, abrigo contra predadores, diminuição de competição em aior disponibilidade de recursos alimentares, estabelecendo uma relação de conectividade com demais ecossistemas costeiros. No presente estudo foi avaliada a estrutura da ictiofauna associada às pradarias de fanerógamas do estuário do Rio Formoso no litoral de Pernambuco durante o inverno de 2008. Foram realizados no total 27 arrastos manuais (15 diurnos e 12 noturnos, nos quais foram amostrados 358 peixes pertencentes a 18 famílias, 21 gêneros e 25 espécies. A Captura por unidade de esforço (CPUE média por arrasto foi de 13,5 indivíduos e 4,95 espécies por arrasto. As famílias mais abundantes foram Scaridae (n = 111, Tetraodontidae (n = 63, Lutjanidae (n = 56, Mullidae (n = 39 e Engraulidae (n = 19. Analisando os índices ecológicos, observou-se que os mesmos foram sempre maiores para o período da noite, confirmando o fato do uso de tais áreas pela ictiofauna de forma mais intensa neste período. A necessidade de medidas para proteção destas áreas é evidente na região devido a sua importância e vulnerabilidade a impactos antrópicos.

  15. Mercury enrichment in sediments of Amba estuary

    Digital Repository Service at National Institute of Oceanography (India)

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

    2009-01-01

    ) 163-178. 7 Williams S C, Simpson H J, Olsen C R & Bopp R F, Sources of heavy metals in sediments ofthe hudson river estuary, Mar Chem, 6 (1978)195-213. 8 Zingde M D & Desai B N, Mercury in Thane Creek, Bombay harbour, Mar Pollut Bull, 12 (1981... of the western Bay of Bengal, Mar Pollut Bull, 18 (1987) 135- 136. 14 Shaw B P, Sahu A, Chaudhari S B & Panigrahi A K, Mercury in the Rushikulya river estuary, Mar Pollut Bull 19 (1988) 233-234. 15 Das S & Sahu B K, Ecological implication of mercury...

  16. PCBs and organochlorine pesticides in blubber biopsies from free-ranging St. Lawrence River Estuary beluga whales (Delphinapterus leucas), 1994-1998

    International Nuclear Information System (INIS)

    Measuring contaminants only in stranded whales may result in overestimation of organochlorines. - For the first time, organochlorine (OC) contaminants were measured in blubber biopsies from free-ranging St. Lawrence River Estuary beluga whales (Delphinapterus leucas), to compare contaminant levels to those previously measured in dead stranded belugas. PCBs, DDTs, toxaphene and chlordane-related compounds were the major OC contaminants detected in 44 belugas biopsied in 1994-1998. ?PCB (the sum of 104 congeners) ranged from 2080 to 128,000 ng/g lipid in males (n=34; minimum estimated ages 8-22 years), and from 148 to 44,100 ng/g lipid in females (n=10; minimum estimated ages 7-22 years). The concentrations of PCBs and OC pesticides in the blubber of these whales overlapped those observed in stranded belugas from an earlier study, and demonstrated comparable age and sex-related trends. However, lower proportions of mirex, HCB, DDTs, and many of the highly chlorinated PCBs occurred in the biopsy samples compared to results for blubber from stranded carcasses. Most major OC compounds were present at lower concentrations in the biopsies, but this does not appear to be solely related to age differences between the two groups, or to emaciation in the stranded whales. Nor does it appear to be associated with the use of superficial biopsies, and the possible stratification of lipids and OCs in the blubber layer. Nevertheless, given these possible confounding factors, and the se possible confounding factors, and the uncertainty in age estimates for the biopsied whales, the results point to the need for careful interpretation of biopsy results when comparing with data taken from the full depth of the blubber mantle in stranded whales. Taken together, results from both biopsied whales and previously studied stranded belugas indicate that PCB and OC pesticide contamination of St. Lawrence beluga whales may occur across a broader range of levels than previously thought, at least for males which formed the largest group in this study, possibly due to different degrees of dietary exposure. It also appears that measuring contaminant concentrations only in stranded whales, may overestimate OC levels in the population as a whole, especially for highly chlorinated OCs

  17. PCBs and organochlorine pesticides in blubber biopsies from free-ranging St. Lawrence River Estuary beluga whales (Delphinapterus leucas), 1994-1998

    Energy Technology Data Exchange (ETDEWEB)

    Hobbs, K.E.; Muir, D.C.G.; Michaud, Robert; Beland, Pierre; Letcher, R.J.; Norstrom, R.J

    2003-04-01

    Measuring contaminants only in stranded whales may result in overestimation of organochlorines. - For the first time, organochlorine (OC) contaminants were measured in blubber biopsies from free-ranging St. Lawrence River Estuary beluga whales (Delphinapterus leucas), to compare contaminant levels to those previously measured in dead stranded belugas. PCBs, DDTs, toxaphene and chlordane-related compounds were the major OC contaminants detected in 44 belugas biopsied in 1994-1998. {sigma}PCB (the sum of 104 congeners) ranged from 2080 to 128,000 ng/g lipid in males (n=34; minimum estimated ages 8-22 years), and from 148 to 44,100 ng/g lipid in females (n=10; minimum estimated ages 7-22 years). The concentrations of PCBs and OC pesticides in the blubber of these whales overlapped those observed in stranded belugas from an earlier study, and demonstrated comparable age and sex-related trends. However, lower proportions of mirex, HCB, DDTs, and many of the highly chlorinated PCBs occurred in the biopsy samples compared to results for blubber from stranded carcasses. Most major OC compounds were present at lower concentrations in the biopsies, but this does not appear to be solely related to age differences between the two groups, or to emaciation in the stranded whales. Nor does it appear to be associated with the use of superficial biopsies, and the possible stratification of lipids and OCs in the blubber layer. Nevertheless, given these possible confounding factors, and the uncertainty in age estimates for the biopsied whales, the results point to the need for careful interpretation of biopsy results when comparing with data taken from the full depth of the blubber mantle in stranded whales. Taken together, results from both biopsied whales and previously studied stranded belugas indicate that PCB and OC pesticide contamination of St. Lawrence beluga whales may occur across a broader range of levels than previously thought, at least for males which formed the largest group in this study, possibly due to different degrees of dietary exposure. It also appears that measuring contaminant concentrations only in stranded whales, may overestimate OC levels in the population as a whole, especially for highly chlorinated OCs.

  18. Bulk organic ? 13C and C/N as indicators for sediment sources in the Pearl River delta and estuary, southern China

    Science.gov (United States)

    Yu, Fengling; Zong, Yongqiang; Lloyd, Jeremy M.; Huang, Guangqing; Leng, Melanie J.; Kendrick, Christopher; Lamb, Angela L.; Yim, Wyss W.-S.

    2010-05-01

    Preservation of organic matter in estuarine and coastal areas is an important process in the global carbon cycle. This paper presents bulk ? 13C and C/N of organic matter from source to sink in the Pearl River catchment, delta and estuary, and discusses the applicability of ? 13C and C/N as indicators for sources of organic matter in deltaic and estuarine sediments. In addition to the 91 surface sediment samples, other materials collected in this study cover the main sources of organic material to estuarine sediment. These are: terrestrial organic matter (TOM), including plants and soil samples from the catchment; estuarine and marine suspended particulate organic carbon (POC) from both summer and winter. Results show that the average ? 13C of estuarine surface sediment increases from -25.0 ± 1.3‰ in the freshwater environment to -21.0 ± 0.2‰ in the marine environment, with C/N decreasing from 15.2 ± 3.3 to 6.8 ± 0.2. In the source areas, C 3 plants have lower ? 13C than C 4 plants (-29.0 ± 1.8‰ and -13.1 ± 0.5‰ respectively). ? 13C increases from -28.3 ± 0.8‰ in the forest soil to around -24.1‰ in both riverbank soil and mangrove soil due to increasing proportion of C 4 grasses. The ? 13C POC increases from -27.6 ± 0.8‰ in the freshwater areas to -22.4 ± 0.5‰ in the marine-brackish-water areas in winter, and ranges between -24.0‰ in freshwater areas and -25.4‰ in brackish-water areas in summer. Comparison of the ? 13C and C/N between the sources and sink indicates a weakening TOM and freshwater POC input in the surface sedimentary organic matter seawards, and a strengthening contribution from the marine organic matter. Thus we suggest that bulk organic ? 13C and C/N analysis can be used to indicate sources of sedimentary organic matter in estuarine environments. Organic carbon in surface sediments derived from anthropogenic sources such as human waste and organic pollutants from industrial and agricultural activities accounts for less than 10% of the total organic carbon (TOC). Although results also indicate elevated ? 13C of sedimentary organic matter due to some agricultural products such as sugarcane, C 3 plants are still the dominant vegetation type in this area, and the bulk organic ? 13C and C/N is still an effective indicator for sources of organic matter in estuarine sediments.

  19. Historic Habitat Opportunities and Food-Web Linkages of Juvenile Salmon in the Columbia River Estuary and Their Implications for Managing River Flows and Restoring Estuarine Habitat, Physical Sciences Component, Progress Report.

    Energy Technology Data Exchange (ETDEWEB)

    Jay, David A. [Portland State University

    2009-08-03

    Long-term changes and fluctuations in river flow, water properties, tides, and sediment transport in the Columbia River and its estuary have had a profound effect on Columbia River salmonids and their habitat. Understanding the river-flow, temperature, tidal, and sediment-supply regimes of the Lower Columbia River (LCR) and how they interact with habitat is, therefore, critical to development of system management and restoration strategies. It is also useful to separate management and climate impacts on hydrologic properties and habitat. This contract, part of a larger project led by the National Oceanic and Atmospheric Administration (NOAA), consists of three work elements, one with five tasks. The first work element relates to reconstruction of historic conditions in a broad sense. The second and third elements consist, respectively, of participation in project-wide integration efforts, and reporting. This report focuses on the five tasks within the historic reconstruction work element. It in part satisfies the reporting requirement, and it forms the basis for our participation in the project integration effort. The first task consists of several topics related to historic changes in river stage and tide. Within this task, the chart datum levels of 14 historic bathymetric surveys completed before definition of Columbia River Datum (CRD) were related to CRD, to enable analysis of these surveys by other project scientists. We have also modeled tidal datums and properties (lower low water or LLW, higher high water or HHW, mean water level or MWL, and greater diurnal tidal range or GDTR) as a function of river flow and tidal range at Astoria. These calculations have been carried for 10 year intervals (1940-date) for 21 stations, though most stations have data for only a few time intervals. Longer-term analyses involve the records at Astoria (1925-date) and Vancouver (1902-date). Water levels for any given river flow have decreased substantially (0.3-1.8 m, depending on river flow and tidal range), and tidal ranges have increased considerably (by a factor of 1.5 to 4 for most river-flow levels) since the 1900-1940 period at most stations, with the largest percentage changes occurring at upriver stations. These changes have been caused by a combination of changes in channel roughness, shape and alignment, changes in coastal tides, and (possibly) bed degradation. Tides are growing throughout the Northeast Pacific, and Astoria (Tongue Pt) has one of the most rapid rates of increase in tidal range in the entire Eastern Pacific, about 0.3m per century. More than half of this change appears to result from changes within the system, the rest from larger scale changes in coastal tides. Regression models of HHW have been used to estimate daily shallow water habitat (SWHA) available in a {approx}25 mile long reach of the system from Eagle Cliff to Kalama for 1925-2004 under four different scenarios (the four possible combinations of diked/undiked and observed flow/ virgin flow). More than 70% of the habitat in this reach has been lost (modern conditions vs. virgin flow with not dikes). In contrast, however, to the reach between Skamokawa and Beaver, selective dike removal (instead of a combination of dike removal and flow restoration) would suffice to increase spring SWHA. The second task consists of reconstruction of the hydrologic cycle before 1878, based on historic documents and inversion of tidal data collected before the onset of the historic flow record in 1878. We have a complete list of freshet times and peak flows for 1858-1877, and scattered freshet information for 1841-1857. Based on tidal data, we have reconstructed the annual flow cycles for 1870 and 1871; other time periods between 1854 and 1867 are under analysis. The three remaining tasks relate to post-1878 hydrologic conditions (flows, sediment supply and water temperature), and separation of the human and climate influences thereon. Estimated ob-served (sometimes routed), adjusted (corrected for reservoir manipulation) and virgin (corrected also for irrigation div

  20. Toxicity of sediments and pore water from Brunswick Estuary, GA

    US Fish and Wildlife Service, Department of the Interior — A chloralkali plant in Brunswick, Ga, discharged 2 kg mercuryday into a tributary of the Turtle RiverBrunswick Estuary from 1966 to 1971. Mercury concentrations in...

  1. Seawater intrusion and behaviour of dissolved boron, fluoride, calcium, magnesium and nutrients in Vashisti Estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Zingde, M.D.; Ram, A.; Sharma, P.; Abidi, S.A.H.

    1995-01-01

    Behaviour of dissolved B, F, Ca, Mg and nutrients in partially stratified estuary of Vashiti River, Karnataka, India has been studied under stable conditions of riverine flow. The dominance of Mg over Ca concentration in river water resulted...

  2. Modelo Geomorfológico De Un Estuario Tropical Caribeño: Desembocadura Del Río Hueque, Costa Oriental Del Estado Falcón, Venezuela / Geomorphologic Model Of A Tropical Estuary In The Caribbean Region: The Mouth Of The Hueque River, East Coast Of The Falcon State, Venezuela

    Scientific Electronic Library Online (English)

    Scarlet, Cartaya; Williams, Méndez.

    2005-04-01

    Full Text Available El propósito principal de este trabajo es establecer un modelo geomorfológico que sintetice la dinámica del sistema estuarino de la desembocadura del río Hueque. Para el desarrollo del modelo se realizaron trabajos de campo en los que se recolectaron muestras de sedimentos de los ambientes depositac [...] ionales identificados, así como mediciones de las dimensiones de éstos, pendientes de playa, batimetría, oleaje y mareas. Se midieron parámetros físicos y químicos del agua como temperatura, pH, salinidad, conductividad eléctrica y transparencia. El trabajo de laboratorio se fundamentó en los análisis de textura, carbonatos, materia orgánica, minerales pesados y mineralogía por difracción de rayos X de las muestras de sedimentos. Se analizaron datos de clima, red de drenaje, mareas y oleaje y se realizó una fotointerpretación detallada del área. El estuario del río Hueque se comporta similar a un caño de marea, con aguas mezcladas y sin estratificación, fuerte tendencia a la hipersalinidad y pH entre neutro y ligeramente básico. Sobre la base de los factores y los procesos implicados, las características sedimentológicas de los ambientes depositacionales y el desarrollo y evolución del área, se concluyó que la desembocadura del río Hueque puede ser definida como un sistema estuarino de edad reciente. Abstract in english The main purpose of this article is to establish a geomorphologic model that synthesizes the dynamics of the estuary system at the mouth of the Hueque River. To develop the model a field study was conducted to collect and measure samples of sediments within the identified depositional environments. [...] Simultaneously other measurements, including beach incline, tides and swell, were carried out. Physical and chemical parameters of the water were measured: temperature, pH, electric conductivity, transparency, and salinity. The laboratory work was based on analysis of textures, carbonates, organic matter, heavy minerals and mineralogy by X-ray diffraction of the sediment samples. Other types of data that was analyzed included, climate, drainage, tides, and swell. In addition, a detail photographic interpretation of the area was done. The Hueque River estuary behaves similarly to a tidal stream with mixed, non-stratified waters, strong tendency to hypersalinity and neutral pH or slightly basic. Based on the factors and implied processes, the sedimentary characteristics of the depositional environments and the development and evolution of the area, it was concluded that the mouth of the Hueque River can be define as a recent estuary system.

  3. Epipelic diatoms in the estuaries of South Africa

    Scientific Electronic Library Online (English)

    GC, Bate; PA, Smailes; JB, Adams.

    2013-01-01

    Full Text Available Epipelic diatom flora was sampled around the South African coast between the Olifants Estuary, on the cool Atlantic Ocean northwest coast, and the St. Lucia Estuary, on the Indian Ocean northeast coast. Altogether, 333 taxa were identified with 14 being ubiquitous, as they were found in the cool tem [...] perate, warm temperate, and subtropical areas, as well as in St. Lucia Estuary situated close to Mocambique. There was little difference between the epipelic diatom species present in intertidal and subtidal areas and, because many of the species have a high tolerance to salinity, with some being found in conditions ranging from freshwater to a salinity of more than 150 psu, it was concluded that many of the species sampled do not appear to be reliable indicators for assessing salinity in South African estuaries. Although there was a wide spread of diatoms across all of the estuaries around the coast, the greatest species similarity occurred between the Olifants, Great Berg and Breede estuaries, suggesting that the Breede Estuary, normally considered to fall within the warm temperate region, may be more similar to the cool temperate type estuaries. Data also showed that there was very little similarity between the diatom flora in the rivers flowing into estuaries and the diatom flora in the estuaries.

  4. Nutrient budgets for large Chinese estuaries

    Directory of Open Access Journals (Sweden)

    S. M. Liu

    2009-10-01

    Full Text Available Chinese rivers deliver about 5–10% of global freshwater input and 15–20% of the global continental sediment to the world ocean. We report the riverine fluxes and concentrations of major nutrients (nitrogen, phosphorus, and silicon in the rivers of the contiguous landmass of China and Korea in the northeast Asia. The rivers are generally enriched with dissolved inorganic nitrogen (DIN and depleted in dissolved inorganic phosphate (PO43? with very high DIN: PO43? concentration ratios. DIN, phosphorus, and silicon levels and loads in rivers are mainly affected by agriculture activities and urbanization, anthropogenic activities and adsorption on particulates, and rock types, climate and physical denudation intensity, respectively. Nutrient transports by rivers in the summer are 3–4 times higher than those in the winter with the exception of NH4+. The flux of NH4+ is rather constant throughout the year due to the anthropogenic sources such as the sewer discharge. As nutrient composition has changed in the rivers, ecosystems in estuaries and coastal sea have also changed in recent decades. Among the changes, a shift of limiting nutrients from phosphorus to nitrogen for phytoplankton production with urbanization is noticeable and in some areas silicon becomes the limiting nutrient for diatom productivity. A simple steady-state mass-balance box model was employed to assess nutrient budgets in the estuaries. The major Chinese estuaries export <15% of nitrogen, <6% of phosphorus required for phytoplankton production and ~4% of silicon required for diatom growth in the Chinese Seas (Bohai, Yellow Sea, East China Sea, South China Sea. This suggests that land-derived nutrients are largely confined to the immediate estuaries, and ecosystem in the coastal sea beyond the estuaries is mainly supported by other nutrient sources such as regeneration, open ocean and atmospheric deposition.

  5. Nutrient elements in large Chinese estuaries

    Science.gov (United States)

    Zhang, Jing

    1996-07-01

    Based on comprehensive observations since 1983, this study summarizes major features of nutrient elements (nitrogen, phosphorus and silicon) in large Chinese river/estuary systems. Elevated nutrient element levels were observed in Chinese rivers, when compared to large and less disturbed aquatic systems (e.g. the Amazon, Zaire and Orinoco). Data from this study are similar to those obtained from the polluted and/or eutrophic rivers in Europe and North America (e.g. the Rhóne and Loire). Nutrient elements may have either conservative or active distributions, or both, in the mixing zone, depending on the element and the estuary. For example, non-conservative behaviors were observed in the upper estuary, where nutrient elements may be remobilized due to the strong desorption and variations of the fresh water end-member, but conservative distributions were found afterwards in the lower estuary. Outside the riverine effluent plumes, nutrient elements may be depleted in surface waters relative to elevated bioproduction, whereas the regeneration with respect to decomposition of organic material and/or nitrification/denitrification offshore, may sustain high levels of nutrient elements in near-bottom waters. Laboratory experiment data generally compares well with field observations. The high fluxes and area] yields of nutrient elements from large Chinese rivers, indicate the extensive use of chemical fertilizers and domestic waste drainage over watersheds in China.

  6. 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

    Directory of Open Access Journals (Sweden)

    M. F. L. de SOUZA

    1999-05-01

    Full Text Available 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 mineralization. In the photic period, NPM ranged from-0.05 to 3.04 mgC.m-2h-1. NEM ranged from -7.77 to 6.65 mgC.m-2.d-1. Bottom ressuspension due to microphytobenthic flotation and a high turbidity plume inside de estuary reflected in negative metabolic rates (mineralization. Benthic metabolism was inferred by net system minus pelagic metabolism. Microphytobenthic community seems to be the main responsible for system metabolism, specially in the upper estuary, although the anthropogenic inputs exert strong long term influence.O metabolismo pelágico líquido (MPL e o metabolismo líquido do ecossistema (MLE foram medidos pela variação do sigmaCO2 em três pontos de amostragem no estuário do Rio Piauí. Na estação a montante, a amostragem foi conduzida durante 48 h. As amostras apresentaram uma alta relação NID:PID. A clorofila-a variou entre 0,2 e 2,5 mig.l-1, com concentrações superiores na estação a montante àquelas de maior influência marinha. O MPL oscilou de -13,2 a 61,2 mgC.m-2.d-1. A presença de material mucilaginoso algal pode explicar os resultados de taxas metabólicas negativas (mineralização. Durante o período fótico, o MPL variou de -0,05 a 3,04 mgC.m-2.h-1. O MLE variou de -7,77 a 6,65 mgC.m-2.d-1. Ressuspensão de sedimento e uma pluma de alta turbidez refletiram-se em episódios de mineralização. Uma estimativa do metabolismo bêntico foi realizada através da diferença entre MLE e MPL. A comunidade microfitobêntica parece ser a principal responsável pelo metabolismo do ecossistema, especialmente na cabeceira do estuário, embora o aporte antropogênico de matéria orgânica e nutrientes exerça forte influência a longo prazo.

  7. Modelling of tidal hydrodynamics for a tropical ecosystem with implications for pollutant dispersion (Cochin Estuary, Southwest India)

    Digital Repository Service at National Institute of Oceanography (India)

    Balachandran, K.K.; Reddy, G.S.; Revichandran, C.; Srinivas, K.; Vijayan, P.R.; Thottam, T.J.

    2008-01-01

    . The present level of pollution in the northern estuary is due to the direct release of industrial effluents into the river Periyar, which can be minimized if they are brought down to central estuary for disposal. The concept of different zones in the estuary...

  8. Environmental flow assessments for transformed estuaries

    Science.gov (United States)

    Sun, Tao; Zhang, Heyue; Yang, Zhifeng; Yang, Wei

    2015-01-01

    Here, we propose an approach to environmental flow assessment that considers spatial pattern variations in potential habitats affected by river discharges and tidal currents in estuaries. The approach comprises four steps: identifying and simulating the distributions of critical environmental factors for habitats of typical species in an estuary; mapping of suitable habitats based on spatial distributions of the Habitat Suitability Index (HSI) and adopting the habitat aggregation index to understand fragmentation of potential suitable habitats; defining variations in water requirements for a certain species using trade-off analysis for different protection objectives; and recommending environmental flows in the estuary considering the compatibility and conflict of freshwater requirements for different species. This approach was tested using a case study in the Yellow River Estuary. Recommended environmental flows were determined by incorporating the requirements of four types of species into the assessments. Greater variability in freshwater inflows could be incorporated into the recommended environmental flows considering the adaptation of potential suitable habitats with variations in the flow regime. Environmental flow allocations should be conducted in conjunction with land use conflict management in estuaries. Based on the results presented here, the proposed approach offers flexible assessment of environmental flow for aquatic ecosystems that may be subject to future change.

  9. Fluoride concentrations in the pineal gland, brain and bone of goosander (Mergus merganser) and its prey in Odra River estuary in Poland.

    Science.gov (United States)

    Kalisinska, Elzbieta; Bosiacka-Baranowska, Irena; Lanocha, Natalia; Kosik-Bogacka, Danuta; Krolaczyk, Katarzyna; Wilk, Aleksandra; Kavetska, Katarzyna; Budis, Halina; Gutowska, Izabela; Chlubek, Dariusz

    2014-12-01

    The aim of the study was to investigate fluoride concentrations in bone, brain and pineal gland of goosander Mergus merganser wintering in the Odra estuary (Poland) as well as in fish originating from its digestive tract. The fluoride concentrations were determined with potentiometric method. Medians of concentrations in goosander had the highest and the lowest values in pineal gland and brain (>760 and pineal gland was significantly greater than in the bone and the brain of the duck. In fish, the fluoride concentration ranged from 37 to 640 mg/kg and significant correlation was revealed between the fluoride concentration and fish weight and length. Based on own results and data of other authors, a daily fluoride intake by the goosander in the Odra estuary was estimated at 15 mg. So high fluoride concentrations like in the duck have not been found in mammal brains. PMID:24744187

  10. Bats of a varzea forest in the estuary of the Amazon River, state of Amapá, Northern Brazil / Morcegos de floresta de várzea no estuário do Rio Amazonas, estado do Amapá, Norte do Brasil

    Scientific Electronic Library Online (English)

    Isai Jorge de, Castro; Fernanda, Michalski.

    Full Text Available As florestas de várzea do estuário do Rio Amazonas ocupam uma extensão 25. 000 km2, abrangendo os estados do Pará e Amapá. Os mamíferos destas florestas, especificamente morcegos ainda são pouco conhecidos. Este estudo visa apresentar uma lista de espécies de morcegos de três localidades em floresta [...] de várzea no estuário do Rio Amazonas, contribuindo assim com o conhecimento da quiropterofauna desta fitofisionomia. Entre Novembro e Dezembro de 2013 foram selecionados 18 sítios de coletas na foz de três rios tributários do Rio Amazonas: Rio Ajuruxí, Rio Maracá e Rio Mazagão. Com o uso de dez redes de neblina (12 x 3 m) armadas ao longo de um transecto linear de 150 metros em cada sitio de coleta e totalizando um esforço amostral de 38,888 m2. h capturamos 403 indivíduos distribuídos em 40 espécies e cinco famílias. As famílias registradas foram Phyllostomidae (n=31 espécies), Emballonuridae (n=6 espécies), Moormopidae (n=1 espécie), Vespertilionidae (n=1 espécie) e Thyropteridae (n=1 espécie). Carollia perspicillata, Artibeus planirostris e Carollia brevicauda compreenderam 45 % dos registros. Nós documentamos o primeiro registro de Glyphonycteris daviesi para o estado do Amapá. Registramos também espécies raras como Dicludurus albus e Macrophyllum macrophylum. Os dados obtidos neste estudo revelam que as florestas de várzea do estuário do Rio Amazonas abrigam uma alta riqueza e diversidade de morcegos e que politicas de conservação devem ser consideradas para a manutenção desta diversidade. Tais politicas devem ser focadas no incentivo para o manejo responsável do cultivo do açaizeiro (Euterpe oleracea) e da exploração da madeira, além da redução da exploração madeireira ilegal que causa prejuízos a fauna e flora dessas florestas ricas em biodiversidade. Abstract in english The varzea forests of the estuary of the Amazon River cover 25,000 km2 within the states of Pará and Amapá. The mammals of those forests, especially bats, are still poorly known. Hence, the present study aimed at inventorying the bat species from three localities of a varzea forest in the estuary of [...] the Amazon River. Between November and December 2013, we selected 18 sampling sites in the mouths of three tributaries of the Amazon River: the rivers Ajuruxí, Maracá, and Mazagão. We set up ten mist nets (12 x 3 m) along a 150-m linear transect in each sampling site, in a total sampling effort of 38,888 m2.h. We captured 403 individual bats of 40 species and five families. We recorded the families: Phyllostomidae (n = 31 species), Emballonuridae (n = 6 species), Moormopidae (n = 1 species), Vespertilionidae (n = 1 species), and Thyropteridae (n = 1 species). Carollia perspicillata, Artibeus planirostris, and Carollia brevicauda comprised 45% of the records. We also made the first record of Glyphonycteris daviesi for Amapá state, and captured rare species, such as Dicludurus albus and Macrophyllum macrophylum. Our results show that the varzea forest of the estuary of the Amazon River harbors high bat diversity, and, hence, conservation policies should be considered for the region. Those policies should encourage the responsible management of açaí palm (Euterpe oleracea) and timber. They should also fight illegal timber exploitation that threatens the fauna and flora of those biodiverse forests.

  11. Rivers and Coasts

    Science.gov (United States)

    This site provides information about rivers, coasts, and the processes affecting them. Students can view an animation of the water cycle, read about how rivers and coasts change, learn about estuaries, and view information on how rivers, coasts, and other water features influence people's lives. Glossaries and a teacher's page offering lesson plans, worksheets, and links to additional sites are also provided.

  12. Salinity and freshwater discharge determine rotifer distribution at the Mossoró River Estuary (Semiarid Region of Brazil Salinidade e descarga de água doce determinam a distribuição de rotíferos no estuário do Rio Mossoró (região semiárida do Brasil

    Directory of Open Access Journals (Sweden)

    AMA. Medeiros

    2010-08-01

    Full Text Available The present study aimed at evaluating differences in rotifer distribution in three estuarine zones in an inverse estuary located in the Semiarid Region of Brazil. Zones were chosen based on their proximity to the ocean and river border as a means of reflecting a horizontal salinity gradient. High freshwater discharge during the rainy season was the major determinant of rotifer composition. On the other hand, due to higher salinity values during the dry season, very low values of species richness and abundance were observed in all zones. Therefore, the study highlights the constraints of salinity and the positive influence of seasonality and river proximity on rotifer species in a semiarid estuarine environment.O presente estudo objetivou avaliar diferenças na distribuição de rotíferos em três zonas estuarinas em um estuário inverso localizado na região semiárida do Brasil. As zonas foram escolhidas com base em suas proximidades com o oceano e a margem do rio de forma a representar um gradiente de salinidade horizontal. A forte entrada de água doce durante o período chuvoso foi o maior determinante da composição de rotíferos. Do outro lado, devido aos maiores valores de salinidade durante o período seco, valores muito baixos de riqueza de espécies e abundância foram observados em todas as zonas. Dessa forma, o estudo demonstra as restrições da salinidade e a influência positiva da sazonalidade e da proximidade com o rio sobre as espécies de rotíferos em um ambiente estuarino do semiárido.

  13. Tidal Asymmetry in Amazon Estuary

    Science.gov (United States)

    Vinzon, S. B.; Gallo, M. N.; Fernandes, R. D.

    2007-05-01

    Estuaries and coastal areas are the last reservoir of fine sediments yield in the continental basins. One of the most interesting questions for each particular system is where the fine sediments are trapped in larger quantities. In the early 90's, a thorough measurement project was held over the Amazon Continental Shelf and coastal zone. One of the results of this project was the register of a huge amount of sediments in suspension over the Shelf, where the turbidity maximum would be located. In order to promote the formation of a turbidity maximum zone, conditions for trapping and deposition are necessary as well as a source of energy to keep sediments in suspension, in general in a feed back way. Several mechanisms can be pointed as responsible for trapping sediments in estuaries and coastal areas. Sediments are carried by currents and the question could be established as which are the main features in the hydrodynamics which contributes to the formation of the turbidity maximum? Flocculation induced by the changes in the flow structure, mainly the reduction in turbulence, can be regarded as one of the mechanisms which contribute to the formation of the turbidity maximum In fact, in-situ measurements showed floc sizes as big as 600µm over the Amazon Shelf. Other feature which strongly affects hydrodynamics and hence trapping sediments is the creation of recirculation zones, related to the estuarine morphology, this aspect, especially important in open areas, is also important in the Amazon Shelf. The role of the shear stress asymmetry and the transport capacity asymmetry both related to the salt stratification structure are also shown as important mechanisms for sediment trapping in this environment. Focusing the understanding of the dynamics of fine sediments in Amazon estuary, the tide asymmetry in the Amazon estuary is analyzed. Changes in the vertical tide asymmetry are observed along the estuary. A positive vertical tide asymmetry is observed in the estuarine region with river influence, which is not indicative of positive velocity asymmetry, as is currently considered for tidal bays, without significant river discharge. Over the Shelf, where salinity intrusion and fluid mud bottom layers occur, negative tidal asymmetry is observed. Causes for the changes of the asymmetry and their consequences for the sediment transport are addressed in this work.

  14. Phytoplankton nyctemeral variation at a tropical river estuary (Itamaracá - Pernambuco - Brazil) Variação nictemeral do fitoplâncton em um estuário tropical (Itamaracá, Pernambuco, Brasil)

    OpenAIRE

    Lacerda, S. R.; Koening, M. L.; Neumann-leita?o, S.; Flores-montes, M. J.

    2004-01-01

    The Botafogo estuary is of socio-economical importance for Pernambuco State. It is located at the north of Santa Cruz Channel, Itamaracá, Pernambuco, Brazil (07º42'50"S and 34º52'10"W). There is a critical need to understand its functioning because of the rate at which this area is being converted to land uses. The phytoplankton dynamics was studied to enhance the knowledge of and verify the possible changes which have occurred in this ecosystem. Sampling was carried out with a plankton ne...

  15. Hermaphroditism among dioecious Tagelus plebeius (Lightfoot, 1786) (Mollusca, Psammobiidae) and Iphigenia brasiliana (Lamarck, 1818) (Mollusca, Donacidae) on the Cachoeira River Estuary, Ilhéus, Bahia, Brazil Hermafroditismo nos moluscos dióicos Tagelus plebeius (Lightfoot, 1786) (Mollusca, Psammobiidae) e Iphigenia brasiliana (Lamarck, 1818) (Mollusca, Donacidae) na região estuarina do Rio Cachoeira, Ilhéus, Bahia, Brasil

    OpenAIRE

    Lo, Ceuta; Boehs, G.; Jjb, Santos

    2010-01-01

    The samples of Tagelus plebeius and Iphigenia brasiliana were manually collected on the Cachoeira River estuary region (Ilhéus, BA, Brazil) between August 2005 and August 2006, with a periodicity of 15 days, with 20 animals collected/sampled, performing 500 samples from each species. The animals were measured, eviscerated and kept in solution of Davidson and after 24-30 hours, they were transferred to ethanol 70%. The material was processed for routine histology, with paraffin embedding, obt...

  16. 2010 Hudson River Shallow Water Sediment Grabs

    National Oceanic and Atmospheric Administration, Department of Commerce — The Hudson River Shallow Water Mapping project characterizes the bottom of the Hudson River Estuary in shallow water (<3 m). The characterization includes...

  17. A chemometric approach to the evaluation of atmospheric and fluvial pollutant inputs in aquatic systems: The Guadalquivir River estuary as a case study

    International Nuclear Information System (INIS)

    To establish the quality of waters it is necessary to identify both point and non-point pollution sources. In this work, we propose the combination of clean analytical methodologies and chemometric tools to study discrete and diffuse pollution caused in a river by tributaries and precipitations, respectively. During a two-year period, water samples were taken in the Guadalquivir river (selected as a case study) and its main tributaries before and after precipitations. Samples were characterized by analysing nutrients, pH, dissolved oxygen, total and volatile suspended solids, carbon species, and heavy metals. Results were used to estimate fluvial and atmospheric inputs and as tracers for anthropic activities. Multivariate analysis was used to estimate the background pollution, and to identify pollution inputs. Principal Component Analysis and Cluster Analysis were used as data exploratory tools, while box-whiskers plots and Linear Discriminant Analysis were used to analyse and distinguish the different types of water samples. - Highlights: ? Atmospheric and fluvial inputs of pollutants in Guadalquivir River were identified. ? Point (tributary rivers) and non-point sources (rains) were studied. ? Nature and extension of anthropogenic pollution in the river were established. - By combining trace environmental analysis and selected chemometric tools atmospheric and fluvial inputs of pollutants in rivers may be identified. The extension of the pollution originated bension of the pollution originated by each anthropic activity developed along the River may be established, as well as the identification of the pollution introduced into the river by the tributary rivers (point sources) and by rains (non-point sources).

  18. Evaluation of the sampling methods applied to phycoperiphyton studies in the Ratones River estuary, Brazil Avaliação dos métodos de coleta aplicados no estudo do ficoperifíton no estuário do rio Ratones, SC, Brasil

    Directory of Open Access Journals (Sweden)

    Bianca Vettorato

    2010-09-01

    Full Text Available AIM: The present study aimed on testing the efficiency of four sampling methods for identification and quantification applied in studies on the biodiversity and spatial-temporal distribution of the phycoperiphyton in the Ratones River estuary; METHODS: The sampling were carried out in three sampling stations along the Ratones River in March and August 2008. The methodologies used for the separation of the periphyton from the sediment were made with the use of sieves and trapping tissue. A removing method through manual agitation and "in situ" analysis was used for epiphytes. To evaluate the efficiency of the methodology for periphyton, data on phytoplankton was included for comparative reasons; RESULTS: The trapping method option was the most appropriate for removing the live specimens from the sediment, and to try to minimize the problems found with the other two methodologies tested. In the case of the epiphytic microalgae the best counting technique resulted from the "in situ" method; CONCLUSIONS: In summary, the results presented here support the difficulties faced in studying phycoperiphytic samples in estuaries, which are shallow and dynamic environments, and for that reason the communities occurring in these areas are constantly influenced by the sediment.OBJETIVO: O presente trabalho tem por objetivo testar a eficiência de quatro métodos de coleta para a identificação e quantificação empregadas no estudo sobre a biodiversidade e distribuição espaço temporal do ficoperifíton no estuário do rio Ratones; MÉTODOS: As coletas foram realizadas em três estações de amostragem ao longo do rio Ratones em março e agosto de 2008. As metodologias testadas para separação do perifíton do sedimento foram realizadas através do uso de peneiras e armadilhas de tecido. Para as epífitas, foi utilizado método de remoção através de agitação manual e análise "in situ". Para avaliar a eficiência da metodologia para perifíton, foram incluídos dados sobre fitoplâncton para fins comparativos; RESULTADOS: A opção pelo método de armadilha mostrou ser mais adequada para separar os espécimes vivos, do sedimento, e para tentar minimizar os problemas encontrados nas outras duas metodologias testadas. No caso das microalgas epífitas, a melhor forma de análise resultou dos métodos "in situ"; CONCLUSÕES: Em síntese, os resultados aqui apresentados reiteram as dificuldades encontradas ao se estudar amostras ficoperifíticas em ambientes estuarinos que, por serem ambientes rasos e dinâmicos, sofrem a influência constante do sedimento na formação das comunidades presentes nestes locais.

  19. Evaluation of the sampling methods applied to phycoperiphyton studies in the Ratones River estuary, Brazil / Avaliação dos métodos de coleta aplicados no estudo do ficoperifíton no estuário do rio Ratones, SC, Brasil

    Scientific Electronic Library Online (English)

    Bianca, Vettorato; Roselane, Laudares-Silva; Dávia, Talgatti; Mariângela, Menezes.

    2010-09-01

    Full Text Available OBJETIVO: O presente trabalho tem por objetivo testar a eficiência de quatro métodos de coleta para a identificação e quantificação empregadas no estudo sobre a biodiversidade e distribuição espaço temporal do ficoperifíton no estuário do rio Ratones; MÉTODOS: As coletas foram realizadas em três est [...] ações de amostragem ao longo do rio Ratones em março e agosto de 2008. As metodologias testadas para separação do perifíton do sedimento foram realizadas através do uso de peneiras e armadilhas de tecido. Para as epífitas, foi utilizado método de remoção através de agitação manual e análise "in situ". Para avaliar a eficiência da metodologia para perifíton, foram incluídos dados sobre fitoplâncton para fins comparativos; RESULTADOS: A opção pelo método de armadilha mostrou ser mais adequada para separar os espécimes vivos, do sedimento, e para tentar minimizar os problemas encontrados nas outras duas metodologias testadas. No caso das microalgas epífitas, a melhor forma de análise resultou dos métodos "in situ"; CONCLUSÕES: Em síntese, os resultados aqui apresentados reiteram as dificuldades encontradas ao se estudar amostras ficoperifíticas em ambientes estuarinos que, por serem ambientes rasos e dinâmicos, sofrem a influência constante do sedimento na formação das comunidades presentes nestes locais. Abstract in english AIM: The present study aimed on testing the efficiency of four sampling methods for identification and quantification applied in studies on the biodiversity and spatial-temporal distribution of the phycoperiphyton in the Ratones River estuary; METHODS: The sampling were carried out in three sampling [...] stations along the Ratones River in March and August 2008. The methodologies used for the separation of the periphyton from the sediment were made with the use of sieves and trapping tissue. A removing method through manual agitation and "in situ" analysis was used for epiphytes. To evaluate the efficiency of the methodology for periphyton, data on phytoplankton was included for comparative reasons; RESULTS: The trapping method option was the most appropriate for removing the live specimens from the sediment, and to try to minimize the problems found with the other two methodologies tested. In the case of the epiphytic microalgae the best counting technique resulted from the "in situ" method; CONCLUSIONS: In summary, the results presented here support the difficulties faced in studying phycoperiphytic samples in estuaries, which are shallow and dynamic environments, and for that reason the communities occurring in these areas are constantly influenced by the sediment.

  20. Detection of Vibrio parahaemolyticus and Vibrio cholerae in oyster, Crassostrea rhizophorae, collected from a natural nursery in the Cocó river estuary, Fortaleza, Ceará, Brazil

    Directory of Open Access Journals (Sweden)

    Sousa Oscarina Viana de

    2004-01-01

    Full Text Available Oysters are edible organisms that are often ingested partially cooked or even raw, presenting therefore a very high risk to the consumers' health, especially in tropical regions. The presence of Vibrio cholerae and Vibrio parahaemolyticus in oysters sampled at an estuary in the Brazilian northeastern region was studied, with 300 oysters tested through an 8-months period. The salinity of the water at the sampling point varied between 3% and 27?. V. cholerae was the most frequently detected species (33.3% of the samples, and of the 22 V. cholerae isolates, 20 were identified as non-O1/non-O139, with two of the colonies presenting a rough surface and most of remaining ones belonging to the Heiberg II fermentation group. V. parahaemolyticus was isolated from just one of the samples. Other bacteria such as Providencia spp., Klebsiella spp. and Morganella morganii were also isolated.

  1. Distribution of 210Po in Mytilus edulis and Fucus vesiculosus along the channel coast of France; influence of industrial releases in the Seine river and estuary

    International Nuclear Information System (INIS)

    From March 1990 to March 1991, the distribution of 210Po in Mytilus edulis and Fucus vesiculosus was studied in the Seine estuary and at adjacent sites. The investigated area has been subject to releases of phosphatic gypsum waste which corresponds to a 'source-term'. In Mytilus edulis, the activity levels vary from 90 to 700 Bq.kg-1 on a dry weight basis, whereas Fucus vesiculosus shows a range of 3-22 Bq.kg-1. The variations of 210Po activity are discussed as a function of time and space. It appears that the 'estuarine source-term' does not affect mussels equally at all seasons of the year. (author)

  2. Freshwater, tidal and wave influences on a small estuary

    Science.gov (United States)

    Uncles, R. J.; Stephens, J. A.; Harris, C.

    2014-10-01

    Observations are presented of water levels, currents, salinity, turbidity, sediment grain sizes and sediment transport in the Devonshire Avon Estuary, UK, in order to improve knowledge of freshwater, wave and tidal influences on small, strongly tidal ría estuaries. A large reduction in tidal range occurred progressing from the coastal zone to the upper estuary that was mainly a consequence of rising bed and river water levels. The spring-neap cycle also had an influence on the reduction in tidal range along the length of the estuary. Surface gravity waves were completely dissipated propagating into the estuarine channel from the coastal zone, and despite strong wave-induced resuspension, suspended sediment was not transported into the lower estuary in observable amounts during the ensuing flood tide, indicating that the wave-suspended material was too coarse to remain in suspension once transported away from the surf zone. Turbidity in the lower estuary was relatively low during low runoff summer conditions and had largest values over low water, when turbid waters from farther up-estuary had been transported there. Strong resuspension events occurred at peak currents in the upper estuary during summer, reflecting the presence of finer-grained sediment sources. Turbidity was similar but greater in the lower estuary during high runoff winter conditions and strong resuspension occurred at peak currents, indicating an easily erodible, nearby sediment source, due to down-estuary movement and relocation of finer sediment over the winter. A large shoal in the lower estuary exhibited a consistent pattern of accretion/erosion during the high runoff months of late autumn and winter to spring that also was qualitatively consistent with sediment transport modelling and implied: (a), erosion from the up-estuary limit of the shoal with (b), down-estuary bed-load and suspended-load transport that accreted the centre and down-estuary limit of the shoal until (c), a diminished supply led to erosion via continued down-estuary transport from the shoal centre.

  3. Residual fluxes of suspended sediment in a tidally dominated tropical estuary

    Science.gov (United States)

    Schettini, Carlos Augusto França; Duarte Pereira, Marçal; Siegle, Eduardo; de Miranda, Luiz Bruner; Silva, Mário P.

    2013-11-01

    This paper assesses the fine sediment fluxes in the Caravelas estuarine system (Bahia, Brazil, 17o45'S and 039o12'W). The estuary reaches the ocean at the shore across from the Abrolhos Bank, the largest tropical reef habitat in the South Atlantic. The Caravelas estuarine system is composed of several meandering channels, which are connected to the ocean by a double inlet system. These two openings - the Caravelas and Nova Viçosa estuaries - are connected by a narrow, 30 km long channel. The Caravelas estuary does not receive significant continental input, while the Nova Viçosa estuary receives the contribution of the Peruíbe River, which drains an area of approximately 5000 km2. To understand the fine sediment dynamics and net transport, observations of tides, currents, salinity and suspended sediment concentration (SSC) were recorded in 13-h tidal surveys (spring and neap tide) and with 20-day long CTDs/ADCP moorings at the Caravelas estuary and in the interconnection channel. The SSC dynamic in the Caravelas estuary is primarily driven by advection, with SSC originating in the inlet and inner shelf area. Residual water and sediment transport are up-estuary in the Caravelas estuary and toward the Caravelas estuary in the interconnection channel. The residual transport showed pronounced synodical modulation and was stronger during spring tide. The Caravelas estuary function as a trap for inner shelf materials and fine sediments delivered by the Peruípe River at Nova Viçosa.

  4. Current Characterization at the Amazon estuary

    Science.gov (United States)

    Bezerra, M. O.

    2009-04-01

    At the estuary there are several mechanisms that cause turbulence: influence of solid contours (estuary bottom and shores), speed vertical shearing (fluid inside), wind shearing stress (free surface) and surface and internal gravity waves. Turbulence intensity controls vertical distribution of estuary water mass property concentration. As flow into the estuary takes place during the transition or turbulent regimen, produced by small space and time scale movements, entrainment, turbulent scattering and advection are the processes responsible for fresh water mixing up with the sea and for local salinity variation, as well as for concentration of natural properties and man-made ones. According to this focus, we shall describe general circulation, conveyance and mixing characteristics of the Amazon low estuary waters. Amazon estuary shows unusual characteristics: it is of vast length and enormous outflow. It is extremely wide - 150 Km - and its discharge into the Atlantic amounts to 180,000 m3s-1 (Otman, 1968, Figueiredo et al, 1991), which means 18% of all water discharged by rivers into oceans; this is the largest punctual source of fresh water for oceans (Milliman and Meade, 1983). Maximum outflow is 2.5 x 105 m3s-1, and it happens at the end of May. Minimum outflow is 1.2 x 105 m3 s-1, and it takes place in November. At Amazon River, the Mixing Zone occurs where the Coastal Zone usually is. The reason for that is the extension of fresh water plume moves Northeast for over 1000 Km (Gibbs, 1970; Muller-Karger et al 1988). This is the most extensive estuarine plume ever found in the ocean. During low fluvial discharge (June-November) plume reaches 300 Km; however, on high discharge (November-May) plume reaches 500 Km. Plume already is 3 to 10 m thick and 80 to 300 Km wide (Lentz and Limeburner, 1995). From June to January plume moves towards Africa, from whence 70% of it goes east carried by North Brazil Current retroflection and 30% goes towards the Caribbean. From February to May, the plume goes northwest towards the Caribbean. As to classification according to salinity stratification, at the quadrature the Amazon estuary is considered as "Saline Wedge" type (highly stratified estuary), salinity at 120 Km way from river moth standing out, whereas at sysygy it can be classified as well mixed (Limeburner et al. 1991e 1992; Patchineelam, 2004). Fresh water is everywhere in the river area, salty or mixed water is located in the ocean. In this estuary 90 Km away from the mouth surface water salinity is less than 0.05 and bottom salinity at 14 m deep is about 19 at high water on quadrature at the end of the rainy season. This behavior produces marked difference in the vertical salinity profile, showing the current is moving in the opposite direction (river fresh water and salty water brought by the tide). In this scenario, speed shearing at the interface produces interfacial friction stress that, from the entrainment process carries portions of water from the sea to the upper part. Usually, therefore, in "saline wedge" (highly stratified estuary) type estuaries, when river discharge is more intensive than the tide wave, entrainment is the predominant mechanism; and the greater tide amplitude is, the greater will its influence be to produce turbulent scattering and mixing be. Probably, at Amazon estuary quadrature entrainment processes are predominant and are the ones responsible for increased salinity in surface layer, whereas turbulence scattering mixing is secondary to it. "Saline wedge" (highly stratified estuary) type estuaries are typical of large fluvial discharge and microtide regions. But although the Amazon estuary is a macrotide region, this stratification is due to the river's exceptional discharge. Due to the remarkable river plume discharge on the platform, the tide - a dominant in macrotide region estuarine circulation - now has a secondary role, albeit not a negligible one, with quadrature amplitudes varying from 2 m to 90 Km from the mouth. It is important to point out that tide-ind

  5. The geomorphology of UK estuaries: The role of geological controls, antecedent conditions and human activities

    Science.gov (United States)

    Pye, Kenneth; Blott, Simon J.

    2014-10-01

    This paper provides an overview of the geomorphological characteristics of UK estuaries and the factors which control them. Many of the features included in previous classifications of UK estuaries are not true estuaries since they do not possess significant river influence. The features considered in this paper to be 'true' estuaries are divided into 'restricted entrance' and 'unrestricted entrance' types on the grounds that the size and geometry of the estuary mouth exerts a critical influence on water levels, tidal currents, wave action, sediment transport and morphological evolution. An estuary which has a wide mouth, narrows and becomes shallower towards the head is likely to be flood dominated, especially if it has a large tidal range, whereas an estuary which has a narrow mouth and widens and/or becomes deeper towards the head is more likely to display ebb dominance, especially if it has a relatively small tidal range. Wide-mouthed estuaries are influenced to a greater degree by wave processes than estuaries with a narrow mouth. Previous authors have hypothesised that estuaries may maintain a state of dynamic equilibrium through alternating periods of flood and ebb dominance, but it is concluded that there is presently no substantive evidence to support this hypothesis. UK estuaries have been affected to varying degrees by embanking, land claim, dredging, sea wall breaching and managed realignment. Some estuaries have adjusted quickly to such perturbations, but others continue to show progressive change, either sedimentary infilling or erosion and sediment loss. The quantification of estuary morphometry, identification of change over time, and testing of hypotheses regarding the morphodynamics and stability of estuaries requires adequate bathymetric/topographic, hydrodynamic and sediment data. At present, such data are available for relatively few UK estuaries.

  6. Evaluation of satellite remote sensing and automatic data techniques for characterization of wetlands and coastal marshlands. [detection and measurement of accretion in estuary system of Atchafalaya River in southern Louisiana

    Science.gov (United States)

    Cartmill, R. H. (principal investigator)

    1974-01-01

    The author has identified the following significant results. ERTS digital data has been used to detect and measure accretion in the large estuarial system of the Atchafalaya River in southern Louisiana. Comparisons of aerial photography taken in October 1970 with a computer printout of ERTS digital data collected on October 1, 1972, show that in a delineated area of 1400 hectares (3460 acres) an accretion of land area in the amount of 112 hectares (277 acres) had occurred. Analysis of band 3 of the ERTS MSS was used to make a land-water map of the area. The accretion test area was marked on this map and the percentage of elements indicated as land was calculated. This percentage was then multiplied by the total test area to obtain the area of land on the date of the ERTS observation for comparison with the aerial photography. Significant improvement in classification accuracy of ERTS MSS data has been achieved by use of a priori probabilities of occurrence in pattern recognition programs. Two classifications were made with accuracies of 76.0% and 81.5%, respectively.

  7. Decomposition of mangrove leaves in the estuary of Paraíba do Sul RiverRio de Janeiro, Brazil / Descomposición de hojas de mangle en el estuario del Río Paraíba do SulRio de Janeiro, Brasil

    Scientific Electronic Library Online (English)

    Taísa, Barroso-Matos; Elaine, Bernini; Carlos, Eduardo Rezende.

    2012-07-01

    Full Text Available La tasa de descomposición de las hojas senescentes de Avicennia germinans, Laguncularia racemosa y Rhizophora mangle en sus respectivas áreas de dominio se analizaron en los manglares del estuario del río Paraíba do Sul, Rio de Janeiro, por el método de bolsas de resíduos. Los resultados indicaron q [...] ue la tasa de descomposición de las hojas de L. racemosa (3,2 x 10-3) no difirió significativamente de A. germinans y R. mangle (P > 0,05), pero A. germinans (5,1 x 10-3) presentó una mayor tasa de descomposición que R. mangle (2,7 x 10-3) (P Abstract in english The decomposition rate of senescent leaves of Avicennia germinans, Laguncularia racemosa and Rhizophora mangle in their respective areas of dominance were analyzed in the estuary mangrove of the Paraíba do Sul River, Rio de Janeiro, by the method of litter bags. Results indicated that the rate of