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Sample records for zhangjiang river estuary

  1. Study on the mangrove ecosystem services value change in Zhangjiang River estuary based on remote sensing and grey relational analysis

    Zhang, Dongshui; Lan, Zhangren; Wang, Qinmin; Wang, Xiaoqin; Zhang, Wei; Li, Zheng

    2007-11-01

    The services of ecosystem are critical to human existence and prosperity, providing necessary ecological products for human production and life as well as indispensable natural conditions for life system. The Natural Mangrove Reserve in Zhangjiang River Estuary is one of the most important National Natural Mangrove Reserve in China. Its environment has been degrading during the past decades for people neglecting the ecosystem services function value which is hard to currency turn. Thus, it is necessary to monitor and assess the Mangrove Reserve's dynamics, both to gain a better understanding of their basic biology and to help guide conservation and restoration efforts. Using Landsat TM/ETM+ Satellite data acquired in 1989, 1992, 1998, 2001 and an Aster image from the year 2003, the land use of the Reserve and its environment were extracted adopting the supervised Maximum Likelihood Classification Algorithm. The changes of land use and ecosystem services value were analyzed using Costanza's method of evaluating the global ecosystem service values. The total value change of ecosystem services in the study area per year are 2945.95×10 4, 2861.74×10 4, 2904.05×10 4, 2794.67×10 4, 2730.82×10 4$ respectively during the four periods (1989-1992, 1992-1998, 1998-2001, 2001-2003). The ecosystem services value change has a close relationship with W&B, population, build-up and forest. The results indicate that the ecosystem services value in the study area has been constantly deteriorating due to the human activities imposed on it, which is highly associated with the local expanding of build-up and brackish water fishponds all the while. And the downward trend of the ecosystem services value has become even more acute, with the development of the local economy.

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

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

    2009-01-01

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

  3. 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 estuary's contribution to the spatial structure and life history diversity of Columbia River salmon...

  4. 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...

  5. 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 estuary's contribution to the spatial structure and life history diversity of Columbia River salmon...

  6. 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...

  7. Columbia River Estuary Ecosystem Classification Cultural Features

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

    2012-01-01

    Estuarine ecosystems are controlled by a variety of processes that operate at multiple spatial and temporal scales. Understanding the hierarchical nature of these processes will aid in prioritization of restoration efforts. This hierarchical Columbia River Estuary Ecosystem Classification (henceforth "Classification") of the Columbia River estuary is a spatial database of the tidally-influenced reaches of the lower Columbia River, the tidally affected parts of its tributaries, and the landforms that make up their floodplains for the 230 kilometers between the Pacific Ocean and Bonneville Dam. This work is a collaborative effort between University of Washington School of Aquatic and Fishery Sciences (henceforth "UW"), U.S. Geological Survey (henceforth "USGS"), and the Lower Columbia Estuary Partnership (henceforth "EP"). Consideration of geomorphologic processes will improve the understanding of controlling physical factors that drive ecosystem evolution along the tidal Columbia River. The mapping extent is the interpreted Holocene geologic floodplain of the tidal Columbia River and its tributaries to the estimated head of tide. Cultural features within the Holocene floodplain were mapped by visual interpretation of Light Detection and Ranging (LiDAR) topography supplemented with aerial photographs and U.S. Geological Survey topographic maps. Mapped cultural features are classified as to their purpose when constructed. Because features were drawn based on LiDAR topography, only features with a significant topographic expression are mapped.

  8. Historical changes in the Columbia River Estuary

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

    Historical changes in the hydrology, sedimentology, and physical oceanography of the Columbia River Estuary have been evaluated with a combination of statistical, cartographic, and numerical-modelling techniques. Comparison of data digitized from US Coast and Geodetic Survey bathymetric surveys conducted in the periods 1867-1875, 1926-1937, and 1949-1958 reveals that large changes in the morphology of the estuary have been caused by navigational improvements (jetties, dredged channels, and pile dikes) and by the diking and filling of much of the wetland area. Lesser changes are attributable to natural shoaling and erosion. There has been roughly a 15% decrease in tidal prism and a net accumulation of about 68 10 6m 3 of sediment in the estuary. Large volumes of sediment have been eroded from the entrance region and deposited on the continental shelf and in the balance of the estuary, contributing to formation of new land. The bathymetric data indicate that, ignoring erosion at the entrance, 370 to 485 10 6m 3 of sediment has been deposited in the estuary since 1868 at an average rate of about 0.5 cm y -1, roughly 5 times the rate at which sea level has fallen locally since the turn of the century. Riverflow data indicate that the seasonal flow cycle of the Columbia River has been significantly altered by regulation and diversion of water for irrigation. The greatest changes have occurred in the last thirty years. Flow variability over periods greater than a month has been significantly damped and the net discharge has been slightly reduced. These changes in riverflow are too recent to be reflected in the available in the available bathymetric data. Results from a laterally averaged, multiple-channel, two-dimensional numerical flow model (described in HAMILTON, 1990) suggest that the changes in morphology and riverflow have reduced mixing, increased stratification, altered the response to fortnightly (neap-spring) changes in tidal forcing, and decreased the salinity intrusion length and the transport of salt into the estuary. The overall effects of human intervention in the physical processes of the Columbia River Estuary (i.e. decrease in freshwater inflow, tidal prism, and mixing; increase in flushing time and fine sediment deposition, and net accumulation of sediment) are qualitatively similar to those observed in less energetic and more obviously altered estuarine systems. A concurrent reduction in wetland habitats has resulted in an estimated 82% reduction in emergent plant production and a 15% reduction in benthic macroalgae production, a combined production loss of 51,675 metric tons of organic carbon per year. This has been at least partially compensated by a large increase in the supply of riverine detritus derived from freshwater phytoplankton primary production. Comparison of modern and estimated preregulation organic carbon budgets for the estuary indicates a shift from a food web based on comparatively refractory macrodetritus derived from emergent vegetation to one involving more labile microdetritus derived from allochthonous phytoplankton. The shift has been driven by human-induced changes to the physical environment of the estuary. While this is a relatively comprehensive study of historical physical changes, it is incomplete in that the sediment budget is still uncertain. More precise quantification of the modern estuarine sediment budget will require both a better understanding of the fluvial input and dredging export terms and a sediment tranport model designed to explain historical changes in the sediment budget. Oceanographic studies to better determine the mechanisms leading to the formation of the turbidity maximum are also needed. The combination of cartography and modelling used in this study should be applicable in other systems where large changes in morphology have occurred in historical time.

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

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

  10. Radiocesium transport in the Hudson River Estuary

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

  11. Riverbed Micromorphology of the Yangtze River Estuary, China

    Shuaihu Wu

    2016-05-01

    Full Text Available Dunes are present in nearly all fluvial channels and are vital in understanding sediment transport, deposition, and flow conditions during floods of rivers and estuaries. This information is pertinent for helping developing management practices to reduce risks in river transportation and engineering. Although a few recent studies have investigated the micromorphology of a portion of the Yangtze River estuary in China, our understanding of dune development in this large estuary is incomplete. It is also poorly understood how the development and characteristics of these dunes have been associated with human activities in the upper reach of the Yangtze River and two large-scale engineering projects in the estuarine zone. This study analyzed the feature in micromorphology of the entire Yangtze River estuary bed over the past three years and assessed the morphological response of the dunes to recent human activities. In 2012, 2014, and 2015, multi-beam bathymetric measurements were conducted on the channel surface of the Yangtze River estuary. The images were analyzed to characterize the subaqueous dunes and detect their changes over time. Bottom sediment samples were collected for grain size analysis to assess the physical properties of the dunes. We found that dunes in the Yangtze River estuary can be classified in four major classes: very large dunes, large dunes, medium dunes, and small dunes. Large dunes were predominant, amounting to 51.5%. There was a large area of dunes developed in the middle and upper reaches of the Yangtze River estuary and in the Hengsha Passage. A small area of dunes was observed for the first time in the turbidity maximum zone of the Yangtze River estuary. These dunes varied from 0.12 to 3.12 m in height with a wide range of wavelength from 2.83 to 127.89 m, yielding a range in height to wavelength of 0.003–0.136. Sharp leeside slope angles suggest that the steep slopes of asymmetrical dunes in the middle and upper reaches, and the turbidity maximum zone of the Yangtze River estuary face predominantly towards tides because of the ebb-dominated currents. Sharp windward slope angles in the lower reach of the North Passage show the influence of flood-dominated currents on dunes. It is likely that the scale of dunes will increase in the future in the South Channel because of a sharp decline of sediment discharge caused by recent human activities.

  12. Palaeoenvironmental evolution of the Seine River estuary during the Holocene

    Frouin, Millena; Sebag, David (ed.); DURAND, Alain; Laignel, Benoit

    2013-01-01

    Quaternary climato-eustatic oscillations and tectonic movements result in base-level changes that modify the shape of fluvial systems. At the onset of the Holocene, NW European fluvial systems were deeply incised and comprised several terraces. Some terraces now lie beneath the estuary that formed in response to the Holocene sea-level rise. The macrotidal estuary of the Seine River is one example of that NW European fluvial valley evolution. Although the system has been extensively studied ov...

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

    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

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

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

    2009-07-01

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

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

    V. R. Shevchenko

    2005-01-01

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

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

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

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

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

  18. Hydrographic and chemical observations in the Sierra Leone River estuary

    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.)

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

    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

  20. Impact of multichannel river network on the plume dynamics in the Pearl River estuary

    Lai, Zhigang; Ma, Ronghua; Gao, Guangyin; Chen, Changsheng; Beardsley, Robert C.

    2015-08-01

    Impacts of the multichannel river network on plume dynamics in the Pearl River estuary were examined using a high-resolution 3-D circulation model. The results showed that during the dry season the plume was a distinct feature along the western coast of the estuary. The plume was defined as three water masses: (a) riverine water (22 psu), respectively. A significant amount of low-salinity water from Hengmen and Hongqimen was transported through a narrow channel between the QiAo Island and the mainland of the Pearl River delta during the ebb tide and formed a local salinity-gradient feature (hereafter referred to as a discharge plume). This discharge plume was a typical small-scale river plume with a Kelvin number K = 0.24 and a strong frontal boundary on its offshore side. With evidence of a significant impact on the distribution and variability of the salinity and flow over the West Shoal, this plume was thought to be a major feature of the Pearl River plume during the dry season. The upstream multichannel river network not only were the freshwater discharge sources but also played a role in establishing an estuarine-scale subtidal pressure gradient. This pressure gradient was one of the key dynamical processes controlling the water exchange between discharge and river plumes in the Pearl River estuary. This study clearly showed the role of the river network and estuary interaction on river plume dynamics.

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

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

    2000-01-01

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

  2. Distribution of endocrine disruptors in the Mondego River estuary, Portugal

    Ribeiro, Cláudia; Pardal, Miguel; Martinho, Filipe; Margalho, Rui; Tiritan, Maria; Rocha, Eduardo; Rocha, Maria

    2008-01-01

    Abstract Recent studies in the Mondego River estuary demonstrated signs of pollution in the area, but the nature of the contamination remains unexplored. Because there seems to be any studies in that zone checking for the simultaneous presence of xenoestrogenic endocrine disrupting compounds, either of animal (estradiol and estrone), vegetal (daidzein, genistein and biochanin A), pharmaceutical (17a-ethynylestradiol) or industrial (bisphenol A, 4-octylphenol, 4-nonylphenol) origins, the main...

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

    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 (1σ) 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 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.)

  4. Oil spill response planning on the Columbia river estuary

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

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

    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

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

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

  7. Sedimentary framework of the Potomac River estuary, Maryland

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

    1981-01-01

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

  8. Expertise mission at the Rance river estuary

    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.)

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

    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

  10. Trace metals geochemistry of Bengkulu river and estuary

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

    2015-09-01

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

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

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

    2014-02-01

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

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

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

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

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

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

    Curt Peterson; Sandy Vanderburgh; Michael C. Roberts

    2014-01-01

    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 s...

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

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

    2013-01-01

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

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

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

    2009-04-01

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

  17. Plutonium AMS measurements in Yangtze River estuary sediment

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

  18. Plutonium AMS measurements in Yangtze River estuary sediment

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

    2010-04-15

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

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

    Drago Magu

    2009-01-01

    In this paper are presented the vision, strategic guidelines/measures and the action plan for shellfish farming development in the Krka river estuary. They came as a result from several discussions that were held with shellfish farmers of the estuary area in year 2008 while writing the Integrated Plan for Shellfish Farming for Krka Estuary Area, which was realized in the framework of the Green Business Support Programme (UNDP COST Project Conservation, and Sustainable Use of Biodiversity in...

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

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

    2008-02-05

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

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

    Cruzeiro, Catarina; Rocha, Eduardo; Pardal, Miguel ngelo; Rocha, Maria Joo

    2016-02-15

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

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

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

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

  3. 2009 Puget Sound LiDAR Consortium (PSLC) Topographic LiDAR: Snohomish River Estuary

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

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

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

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

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

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

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

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

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

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

    2012-01-01

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

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

    M. Taufik Kaisupy

    2006-04-01

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

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

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

    1993-01-01

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

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

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

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

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

    2011-03-01

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

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

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

    2012-08-01

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

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

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

    2008-02-20

    The purpose of this document is to describe research, monitoring, and evaluation (RME) for the Federal Columbia River Estuary Program, hereafter called 'the Estuary Program'. The intent of this RME effort is to provide data and information to evaluate progress toward meeting program goals and objectives and support decision making in the Estuary Program. The goal of the Estuary Program is to understand, conserve, and restore the estuary ecosystem to improve the performance of listed salmonid populations. The Estuary Program has five general objectives, designed to fulfill the program goal, as follows: (1) Understand the primary stressors affecting ecosystem controlling factors, such as ocean conditions and invasive species. (2) Conserve and restore factors controlling ecosystem structures and processes, such as hydrodynamics and water quality. (3) Increase the quantity and quality of ecosystem structures, i.e., habitats, juvenile salmonids use during migration through the estuary. (4) Maintain the food web to benefit salmonid performance. (5) Improve salmonid performance in terms of life history diversity, foraging success, growth, and survival. The goal of estuary RME is to provide pertinent and timely research and monitoring information to planners, implementers, and managers of the Estuary Program. The goal leads to three primary management questions pertaining to the main focus of the Estuary Program: estuary habitat conservation and restoration. (1) Are the estuary habitat actions achieving the expected biological and environmental performance targets? (2) Are the offsite habitat actions in the estuary improving juvenile salmonid performance and which actions are most effective at addressing the limiting factors preventing achievement of habitat, fish, or wildlife performance objectives? (3) What are the limiting factors or threats in the estuary/ocean preventing the achievement of desired habitat or fish performance objectives? Performance measures for the estuary are monitored indicators that reflect the status of habitat conditions and fish performance, e.g., habitat connectivity, survival, and life history diversity. Performance measures also pertain to implementation and compliance. Such measures are part of the monitoring, research, and action plans in this estuary RME document. Performance targets specific to the estuary were not included in the 2007 draft Biological Opinion.

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

    Regla Duthit Somoza

    2011-04-01

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

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

    U.S. Bonneville Power Administration

    2008-08-01

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

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

    Drago Magu

    2009-10-01

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

  17. Structure and Seasonal Dynamics of Larval Fish in the Caet River Estuary in North Brazil

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

    2002-02-01

    The larval fish assemblage was examined along a salinity gradient of the Caet River Estuary situated in northern Brazil. A total of 35 555 larvae, representing 28 families and 63 taxa were collected in samples taken monthly between July 1996 and September 1997, with a mean concentration of 9 individuals per 100 m 3. Sciaenidae was the most abundant family comprising 465% (11 species) of all teleosts sampled in the Caet River Estuary, followed by Engraulidae (419%, seven species). The most abundant larval taxa were the engraulid Anchovia clupeoides and the sciaenid Stellifer microps accounting together for 704% of the total catch. The most abundant developmental stages of A. clupeoides was preflexion larva, confirming that this species is resident. Apart from estuarine species, the upper estuary additionally has taxa associated with freshwater conditions, whereas species with marine affinities were captured in the lower estuary. The densities of most species were influenced to a greater degree by site than by season, showing maximum densities in the upper estuary. Larval density peaked in the upper estuary during the dry season and was lowest when freshwater discharge was at its maximum, which was attributed to an increased seaward drift of larvae. Species number was greatest in the upper estuary between the rainy and dry season.

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

    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

  19. Chlorophyll a and phytoplankton maximum at the halocline of Ebro River estuary.

    Falco, S.; Romero Gil, Inmaculada; Rodilla, M; J. P. Sierra; González del Rio Rams, Julio; C. Mösso; Pérez Baliero, Mª del Carmen

    2006-01-01

    The Ebro River flows into the Mediterranean coast of Spain and its last stretch behaves most of the time as a highly stratified estuary. Four field campaigns were carried out during years 1999-2000 to study water quality within the estuary. In this paper, the results of two of these field campaigns are shown. These results are based on the development of a new sampling technique, which allows obtaining samples at the halocline with a high resolution. As a consequence, concentratio...

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

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

    2016-01-01

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

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

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

    2015-01-01

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

  2. PREDICTION OF TSUNAMI PROPAGATION IN THE PEARL RIVER ESTUARY

    Sun J. S.

    2009-01-01

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

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

    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

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

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

    2005-05-01

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

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

    Cukrov, Neven; Barii?, Delko

    2006-01-01

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

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

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

    2015-12-01

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

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

    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

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

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

    1985-11-01

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

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

    Chen, Qiuying; Ho, KinChung; Liu, Jingling

    2014-01-01

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

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

    Peng Zhang

    2015-08-01

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

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

    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.

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

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

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

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

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

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

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

    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.

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

    Kärnä, Tuomas; Baptista, António M.

    2016-03-01

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

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

    Li, Ya-Fang; XU, Run-lin

    2013-01-01

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

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

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

    2006-12-01

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

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

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

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

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

    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)

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

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

    2015-03-01

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

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

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

    2007-12-01

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

  3. Reconstruction of an 8,000-year record of typhoons in the Pearl River estuary, China

    Huang, G.; Yim, WWS

    2007-01-01

    An 8,000-year record of typhoons in the Pearl River Estuary is reconstructed through the study of offshore boreholes, beach-dune barriers, historical record and instrumental documentation. In 5 offshore boreholes, a maximum of 17 siliciclastic-dominated storm beds and/or shell-dominated storm beds was identified since about 8,000 calendar years BP. Holocene beach-dune barriers in the vicinity of the estuary were used to study the distribution of landfalling typhoons assisted by ra...

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

    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.

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

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

    in the lower reaches of the Mandovi River estuary, from 138/g dry sediment sample in 1994 to 41/g sediment sample in 2001. The decline is also noted in diversity from 22 in 1994 to only 5 species in 2001. The ever-increasing suspended load in Mandovi estuary...

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

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

    2010-02-01

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

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

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

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

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

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

    2015-09-01

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

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

    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.

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

    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

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

    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.

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

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

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

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

    1984-09-01

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

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

    Minhan Dai

    2008-04-01

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

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

    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.

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

    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

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

    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 μg/ g dry weights and 18.65± 7.65 μg/ 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)

  18. Metal surveys in South African estuaries I. Swartkops River

    Water, surface sediment and sediment core samples were collected from sites in the Swartkops River up to 15 km from the mouth and analysed for up to sixteen elements. The results indicate the presence of four main areas of contamination in the river, at Redhouse, Swartkops, the brickworks and Amsterdam Hoek. The accumulation of zinc, copper, lead and nickel by oysters grown at the mouth of the river confirms the presence of greater than normal metal concentrations in the river. Fish-water Flats outfall contributes metals to the nearshore marine environment, but the strong tidal sweep disperses the effluent relatively quickly so that metal build-up in the area is minimal. In general, metal levels in the Swartkops River are low and, as yet, the area cannot be described as 'polluted' in the true sense of the word

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

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

    2013-11-30

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

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

    D. R. Corbett

    2010-01-01

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

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

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

    2016-01-15

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

  2. Stratified communities of active archaea in shallow sediments of the Pearl River Estuary, Southern China.

    Chen, Jinquan; Wang, Fengping; Jiang, Lijing; Yin, Xijie; Xiao, Xiang

    2013-07-01

    Marine subsurface sediments represent a novel archaeal biosphere with unknown physiology. To get to know the composition and ecological roles of the archaeal communities within the sediments of the Pearl River Estuary, Southern China, the diversity and vertical distribution of active archaea in a sediment core were characterized by 16S rRNA phylogenetic analysis of clone libraries derived from RNA. In this study, the archaeal diversity above, within, and beneath the sulfate-methane transition zone (SMTZ) in the Pearl River Estuary sediment core was described. The majority of the clones obtained from the metabolically active fraction of the archaeal community were most closely related to miscellaneous crenarchaeotal group and terrestrial miscellaneous euryarchaeotal group. Notably, although the Pearl River Estuary sediment belong to high methane and high organic carbon environment, sequences affiliated with methanotrophic and methanogenic archaea were detected as minor group in 16S rRNA clone libraries. No obvious evidence suggested that these unknown archaeal phylotypes related directly to anaerobic oxidation of methane in SMTZ. This is the first phylogenetic analysis of the metabolically active fraction of the archaeal community in the coastal sediment environments. PMID:23404650

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

    Biplob Das

    2002-01-01

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

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

    Chen, Hao; Lei, Kun; Wang, Xuechun

    2016-04-01

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

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

    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.

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

    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.

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

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

    2008-01-01

    Deposition of Hudson River sediment into New York Harbor interferes with navigation lanes and requires continuous dredging. Sediment dynamics at the Hudson estuary turbidity maximum (ETM) have received considerable study, but delivery of sediment to the ETM through the freshwater reach of the estuary has received relatively little attention and few direct measurements. An acoustic Doppler current profiler was positioned at the approximate limit of continuous freshwater to develop a 4-year time series of water velocity, discharge, suspended sediment concentration, and suspended sediment discharge. This data set was compared with suspended sediment discharge data collected during the same period at two sites just above the Hudson head-of-tide (the Federal Dam at Troy) that together represent the single largest source of sediment entering the estuary. The mean annual suspended sediment-discharge from the freshwater reach of the estuary was 737,000 metric tons. Unexpectedly, the total suspended sediment discharge at the study site in November and December slightly exceeded that observed during March and April, the months during which rain and snowmelt typically result in the largest sediment discharge to the estuary. Suspended sediment discharge at the study site exceeded that from the Federal Dam, even though the intervening reach appears to store significant amounts of sediment, suggesting that 30-40% of sediment discharge observed at the study site is derived from tributaries to the estuary between the Federal Dam and study site. A simple model of sediment entering and passing through the freshwater reach on a timescale of weeks appears reasonable during normal hydrologic conditions in adjoining watersheds; however, this simple model may dramatically overestimate sediment delivery during extreme tributary high flows, especially those at the end of, or after, the "flushing season" (October through April). Previous estimates of annual or seasonal sediment delivery from tributaries and the Federal Dam to the ETM and harbor may be high for those years with extreme tributary high-flow events. ?? 2008 Coastal and Estuarine Research Federation.

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

    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.

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

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

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

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

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

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

    2016-03-01

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

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

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

    2013-09-01

    We used radium isotopes as tracers to characterize coastal hydrodynamics and submarine groundwater discharge (SGD) in the Yellow River Estuary in order to assess the ecological effects in one of the most turbid estuaries in the world. Based on apparent water ages calculated by 224Ra/223Ra activity ratios, we found that the river plume flowed mainly southeast at a flow rate of 5-7 km d-1, while a small portion of the river plume was diverted northeast to the central Bohai Sea at a flow rate of less than 2 km d-1. We estimate that with this flow regime, nutrients would be consumed within about two weeks mostly by microplankton and nanoplankton near shore, and picoplankton further offshore to support an average primary production of 0.14 g C m-2 d-1. We then used a 226Ra mass balance model to quantify the SGD flux in the study area. The estimated SGD flux was 1.3109 m3 d-1 with a range of 2.8108-3.0109 m3 d-1. Even the minimum SGD value was about 3 times higher than the Yellow River discharge at that time. The SGD input of dissolved nutrients was shown to be very important to the estuarine nutrient budget, at least 5 times higher than river input. Sediment regeneration of nutrients proved to be very small relative to the SGD flux in this region.

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

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

    2014-02-01

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

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

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

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

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

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

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

    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.

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

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

    2003-01-01

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

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

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

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

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

    2016-02-01

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

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

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

    2012-12-01

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

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

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

    2016-03-01

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

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

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

    2016-07-01

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

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

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

    2014-02-01

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

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

    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.

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

    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

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

    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)

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

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

    2009-04-01

    Estimates of mercury (Hg) loadings to the Arctic Ocean from circumpolar rivers have not considered biogeochemical changes that occur when river water is temporarily stored in large deltas (delta effect). There are also few data describing Hg changes across the freshwater-saltwater transition zone (FSTZ) of these rivers. We assessed temporal changes in unfiltered total mercury (THg) and methylmercury (MeHg) concentrations during open-water 2004 in the Mackenzie River upstream of the Mackenzie River delta, and in 6 floodplain lakes across an elevation gradient. These data were used to calculate Hg fluxes from the Mackenzie River and to evaluate a delta effect on Hg using an estimate of delta river water storage and a mixing analysis. Mean THg concentrations were highest in river water (9.17+/-5.51 ng/L) and decreased up the lake elevation gradient. Mean MeHg concentrations were highest in lakes periodically connected to the river (0.213+/-0.122 ng/L) and MeHg concentrations in elevated lakes showed a mid-summer peak. Results from the mixing analysis showed that the delta effect may be large enough to affect Hg loadings to the Arctic Ocean. THg concentrations exiting the delta (10.2 ng/L) were 16% lower than those entering (12.1 ng/L), whereas MeHg showed little change. We calculated 2.5-month (open-water) THg and MeHg fluxes from the Mackenzie River of 1208 and 8.4 kg. These fluxes are similar in magnitude to previous annual estimates in the arctic literature suggesting that previously published annual Hg fluxes from the Mackenzie River may be large underestimates. We also assessed changes in Mackenzie River water THg and MeHg concentrations as it crossed the FSTZ during an open-water cruise. THg decreased non-conservatively across the estuary from 3.8-0.6 ng/L, possibly due to mixing and particle settling. MeHg concentrations were variable and near detection. Our results show that the Mackenzie River estuary is a dynamic environment and may have important controls on Hg delivered to the Arctic Ocean. PMID:19215970

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

    Pakenham, A.; Wheatcroft, R.

    2008-12-01

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

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

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

    2016-02-01

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

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

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

    2009-04-01

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

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

    Christina Vinson; Grazielle Gomes; Horacio Schneider; Iracilda Sampaio

    2004-01-01

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

  12. Nitrate sources and dynamics in the salinized rivers and estuaries a ?15N- and ?18O-NO3 isotope approach

    D. Xue

    2014-03-01

    Full Text Available To trace NO3 sources and assess NO3 dynamics in the salinized rivers and estuaries, three rivers (HH River, CB River and JY River and two estuaries (HH Estuary and CJ Estuary along the Bohai Bay (China have been selected to determine DIN and ?15N and ?18O-NO3. Upstream of the HH River NO3 was removed 30.9 22.1% by aerobic denitrification, resulting from effects of the floodgate: limiting water exchange with downstream and prolonging water residence time to remove NO3. Downstream of the HH River NO3 was removed 2.5 13.3% by NO3 turnover processes. Conversely, NO3 was increased 36.6 25.2% by external N source addition in the CB River and 34.6 35.1% by in-stream nitrification in the JY River, respectively. The HH and CY Estuaries behaved mostly conservative excluding the sewage input in the CJ Estuary. Hydrodynamics in estuaries have been changed by the ongoing reclamation projects, aggravating the estuaries losing the attenuation function of NO3.

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

    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)

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

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

    1999-01-01

    This Florida Geological Survey/U.S. Department of the Interior, Minerals Management Service Cooperative Study provides baseline data for major and trace metal concentrations in the sediments of the Steinhatchee River estuary. These data are intended to provide a benchmark for comparison with future metal concentration data measurements. The Steinhatchee River estuary is a relatively pristine bay located within the Big Bend Wildlife Management Area on the North Central Florida Gulf of Mexico coastline. The river flows 55 km through woodlands and planted pines before emptying into the Gulf at Deadman Harbor. Water quality in the estuary is excellent at present. There is minimal development within the watershed. The estuary is part of an extensive system of marshes that formed along the Florida Gulf coast during the Holocene marine transgression. Sediment accretion rate measurements range from 1.4 to 4.1 mm/yr on the basis of lead-210 measurements. Seventy-nine short cores were collected from 66 sample locations, representing four lithofacies: clay- and organic-rich sands, organic-rich sands, clean quartz sands, and oyster bioherms. Samples were analyzed for texture, total organic matter, total carbon, total nitrogen, clay mineralogy, and major and trace-metal content. Following these analyses, metal concentrations were normalized against geochemical reference elements (aluminum and iron) and against total weight percent organic matter. Metals were also normalized granulometrically against total weight percent fines (metals except mercury. Mercury concentrations were determined by cold-flameless atomic absorption spectrometry (AAS). Granulometric measurements were made by sieve and pipette analyses. Organic matter was determined by two methods: weight loss upon ignition and elemental analysis (by Carlo-Erba Furnace) of carbon and nitrogen. X-ray diffraction was used to determine clay mineralogy. Trace-metal concentrations were best correlated when normalized with respect to sediment aluminum concentrations. Normalizations indicate that most major and trace-metal concentrations fall within 95% prediction limits of the expected value. This finding suggests that little significant metal contamination occurred within this system prior to 1994 sediment sampling. Exceptions include lead, mercury, copper, zinc, potassium, and phosphorous. Lead and mercury are elements that generally enter this watershed through atmospheric deposition; thus, anomalous levels of these metals are not necessarily associated with activities within the watershed of the Steinhatchee River estuary. Anomalous concentrations of other metals such as zinc, copper, and phosphorous probably do originate within the Steinhatchee watershed. Copper failed to correlate well with any geochemical or granulometric normalizer, and this condition was not limited to a single facies or area within the estuary. This finding may indicate copper contamination in the system. Increased zinc and copper levels may be attributed to marine paints. Phosphorous levels also appeared to be elevated in a few locations in the two marsh facies sampled. This may be due to nutrient loading from two small communities, Jena and Steinhatchee, or from the application of this element in fertilizer to reduce moisture stress to young planted pines on tree farms within the watershed.The Florida Geological Survey/US Department of the Interior, Minerals Management Service Cooperative Study provides baseline data for major and trace metal concentrations in the sediments of the Steinhatchee River estuary. The data are intended to provide a benchmark for comparison with metal concentration data measurements. Seventy nine short cores were collected from 66 sample locations and analyzed. Metal concentrations were normalized against geochemical reference elements and against total weight percen

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

    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

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

    Pang, A. P.; Sun, T.

    2013-12-01

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

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

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

    2009-09-01

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

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

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

    2005-01-01

    The latest Holocene sedimentary record of a cohesive channel and subtidal shoal in the lower Hudson River Estuary was examined to elucidate natural (sea-level rise, sediment transport) and anthropogenic (bulkheading, dredging) influences on the recent morphodynamic evolution of the system. To characterize the seafloor and shallow subbottom, ??? 100 km of high-resolution seismic reflection profiles (chirp) were collected within a 20-km reach of the estuary and correlated with sediment lithologies provided by eight vibracores recovered along seismic lines. Sediment geochronology with 137Cs and 14C was used to estimate intermediate and long-term sedimentation rates, respectively, and historical bathymetric data were analyzed to identify regional patterns of accretion and erosion, and to quantify changes in channel geometry and sediment volume. The shoal lithosome originated around 4 ka presumably with decelerating eustatic sea level rise during the latest Holocene. Long-term sedimentation rates on the shoal (2.3-2.6 mm/yr) are higher than in the channel (2 mm/yr) owing to hydrodynamic conditions that preferentially sequester suspended sediment on the western side of the estuary. As a result, the shoal accretes oblique to the principal axis of tidal transport, and more rapidly than the channel to produce an asymmetric cross-section. Shoal deposits consist of tidally bedded muds and are stratified by minor erosion surfaces that seismic profiles reveal to extend for 10s of meters to kilometers. The frequency and continuity of these surfaces suggest that the surficial shoal is catastrophically stripped on decadal-centennial time scales by elevated tidal flows; tidal erosion maintains the shoal at a uniform depth below sea level and prevents it from transitioning to an intertidal environment. Consequently, the long-term sedimentation rate approximates the rate of sea-level rise in the lower estuary (1-3 mm/yr). After the mid 1800s, the natural geometry of the lower Hudson River Estuary changed rapidly in response to engineering works that forced the channel to self-deepen. Analysis of historical bathymetric data indicates that the channel lost an estimated 3 ?? 106 tons of sediment between ca. 1939 and 2002 (50,000 tons/yr average) by subaqueous erosion, increasing in depth by as much as 4 m in places. Erosion appears to have been concurrent with systematic bulkheading of the shoreline after ca. 1865, which decreased the estuary surface area by ??? 19% overall. Evidently, self-deepening of the channel is a morphodynamic adjustment to reestablish equilibrium cross-sectional area, yet the state of this change locally and elsewhere in the estuary is unknown. Subaqueous erosion documented in this study is a significant source of sediment with implications to the sediment budget and environmental quality of the Hudson River Estuary. ?? 2005 Elsevier B.V. All rights reserved.

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

    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.

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

    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

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

    F. Cheng

    2012-06-01

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

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

    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 Σ17PBDE). 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 Σ10PBDE (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 Σ10PBDE 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 Σ10PBDE 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.

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

    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.

  4. 18O and 226Ra in the Minjiang River estuary, China and their hydrological implications

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

    2016-05-01

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

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

    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/).

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

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

    2010-07-15

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

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

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

    2014-03-01

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

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

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

    2016-03-01

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

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

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

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

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

    2012-01-01

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

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

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

    1985-12-01

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

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

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

  13. Occurrences of Salmonella spp. in water and soil sample of the Karnafuli river estuary

    Mohammad Zafar; Md. Wahidul Alam

    2012-01-01

    This study was carried out to examine the presence of Salmonella spp. in soil and water sample along with some physio-chemical parameters of water at the Karnafuli river estuary during March-June 2012 from 3 stations. The ranges of measured parameters of water samples were 26.5- 32ºC, 0.0 – 5.0‰, 7.5 – 7.9 and 2.28 – 2.91mg/l for temperature, salinity, pH and dissolved oxygen (DO), respectively.. In the present investigation, it was observed that the values of physio chemical parameters in th...

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

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

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

    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 non-point sources in the estuary

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

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

    2016-05-01

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

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

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

    2012-04-01

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

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

    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.

  19. Analysis of thermal impact in tidal rivers and estuaries

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

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

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

    2013-02-01

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

  1. 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

    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

  2. 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

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

    1982-01-01

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

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

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

    2013-03-01

    Phytoplankton and environmental variables were measured monthly from July 2009 to August 2011 in the Maixi River from the estuary to Baihua Reservoir in the Maotiao River catchment, southwestern China, to understand phytoplankton community structure and environmental factors. The relationship between phytoplankton community structure and environmental factors including hydrological, meteorological, physical, and chemical variables were explored using multivariate analysis. A total of 81 taxa of phytoplankton were identified, which were mainly composed of chlorophyta, bacillariophyta, and cyanobacteria. The phytoplankton community was dominated by Pseudanabaena limnetica during summer and fall and by Cyclotella meneghiniana during winter and spring. The abundance of phytoplankton ranged from 0.24104 cells/L to 33.45106 cells/L, with the minimum occurring during February 2010 and the maximum during July 2009. The phytoplankton community was dominated mainly by cyanobacteria from April to September, and by bacillariophyta and pyrrophyta from October to March. Canonical correspondence analysis showed that temperature, pH values, and orthophosphate were the most important driving factors regulating the composition and dynamics of the phytoplankton community in the estuary. Cyanobacteria and euglenophyta abundance and biomass were affected mainly by temperature and pH values, while most chlorophyta and bacillariophyta were influenced by the concentrations of nutrients.

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

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

    2015-06-01

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

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

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

    2015-10-01

    The Pearl River delta, one of the most prosperous economically region in China, has experienced significant contaminant inputs. However, the dynamics of pollutants in the Pearl River estuary and the adjacent coastal areas are still unclear at present. In the paper, distribution and sources of polycyclic aromatic hydrocarbons (PAHs) were investigated in the surface sediments of the Pearl River estuary. The total PAHs concentrations ranged from 126.08 to 3828.58 ng/g with a mean value of 563.52 ng/g, whereas the highest PAHs were observed in Guangzhou channel. Among the U.S. Environmental Protection Agency's 16 priority PAHs, PAHs with 3-4 rings exhibited relative higher levels. A positive relationship was found between PAHs and total organic carbon. The source analysis further showed that the major sources of PAHs in the Pearl River estuary were originated from the pyrolytic inputs, reflecting a mixed energy structure such as wood, coal and petroleum combustion. In summary, although PAHs in Lingding Bay and the adjacent coastal areas of the Pearl River estuary exhibited a relatively low pollution level, the relatively high pollution level of PAHs in Guangzhou channel will be attended. PMID:26040842

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

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

    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 2.41 ng g(-1) dw (dry weight) with an average value of 0.79 ng g(-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

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

    B.Y. Kamaruzzaman

    2009-01-01

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

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

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

    2011-09-01

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

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

    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).

  11. Preliminary study on the dissolved and colloidal organic carbon in the Zhujiang River estuary

    Dai, Min-Han; Martin, Jean-Marie; Hong, Hua-Sheng; Zhang, Zu-Lin

    2000-09-01

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

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

    Ni, Zhixin; Huang, Xiaoping; Zhang, Xia

    2015-06-01

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

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

    Pang, Aiping; Sun, Tao; Yang, Zhifeng

    2013-03-01

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

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

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

    2010-08-01

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

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

    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 analyses to compare growth and residency among individuals collected in tidal-fresh water wetlands of the lower main-stem estuary. Although no known otolith structural or chemical indicators currently exist to define entry into tidal fresh environments, our previous analyses indicate that otolith barium concentrations frequently increase before individuals encounter salt water. Here we evaluate whether otolith barium levels may provide a valid indicator of tidal fresh water entry by Columbia River Chinook salmon. We also examine otolith growth increments to quantify and compare recent (i.e., the previous 30 d) growth rates among individuals sampled in different wetland habitats along the estuarine tidal gradient.

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

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

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

    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

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

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

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

    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

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

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

    2015-07-21

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

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

    Draft annual report for the Cumulative Effects Study for the US Army Corps of Engineers, Portland District. This is the fifth annual report of a seven-year project (2004 through 2010) to evaluate the cumulative effects of habitat restoration actions in the 235-km-long Columbia River estuary. The project, called the Cumulative Effects Study, is being conducted for the U.S. Army Corps of Engineers, Portland District (CENWP), by the Marine Sciences Laboratory of the Pacific Northwest National Laboratory (PNNL), the Pt. Adams Biological Field Station of the National Marine Fisheries Service (NMFS), and the Columbia River Estuary Study Taskforce (CREST). The goal of the Cumulative Effects Study is to develop a methodology to evaluate the cumulative effects of multiple habitat restoration projects intended to benefit ecosystems supporting juvenile salmonids in the lower Columbia River and estuary (LCRE). Literature review in 2004 revealed no existing methods for such an evaluation and suggested that cumulative effects could be additive or synergistic. From 2005 through 2008, annual field research involved intensive, comparative studies paired by habitat type (tidal swamp versus marsh), trajectory (restoration versus reference site), and restoration action (tide gate versus culvert versus dike breach). During 2008, the specific objectives for the Cumulative Effects Study were to do the following: (1) Summarize the adaptive management framework for LCRE habitat restoration activities; (2) Finalize the levels-of-evidence approach and ecological theory underpinning the analysis, synthesis, and evaluation of the cumulative effects of multiple habitat restoration projects in the LCRE; (3) Summarize new results from analyses from 2005-2008 project research for the purpose of cumulative effects evaluation in the LCRE; (4) Initiate a synthesis and evaluation of cumulative effects in the LCRE; (5) Assess management implications, lessons learned, decision-making, 2009-2010 research, and final project deliverables; and (6) Provide a hydrodynamic model assessment of synergistic effects, analysis summaries of the additive modeling pilot study, natural breach and habitat creation sites, wetted area, hydrology and fish, monitoring summaries for Julia Butler Hanson Wildlife Refuge and Crims Island, and a preliminary meta-analysis of effectiveness monitoring data.

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

    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.

  3. 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

    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

  4. 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

    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.

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

    Lpez-Lpez J. A.

    2013-04-01

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

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

    Lanlan Cai

    2016-02-01

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

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

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

    2016-01-01

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

  8. Dissolved inorganic carbon (DIC) and its δ13C in the Ganga (Hooghly) River estuary, India: Evidence of DIC generation via organic carbon degradation and carbonate dissolution

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

    , and they constitute ca. 2–3% of the river water DIC concentrations.The estimated annual DIC flux from the estuary to the Bay of Bengal is ca. (3–4) × 1012 g, of which ca. 40–50% is generated within the estuary. The monsoon periods account for the majority...

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

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

    2004-05-01

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

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

    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.

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

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

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

    Hayes, David W.; Sackett, William M.

    1987-08-01

    A study was made of the 239Pu, 240Pu, 238Pu and 137Cs concentrations in tidal marsh sediments of the Savannah River estuary. Tidal marshes are identified as special locations for plutonium deposition because of the high biological productivity and relative stability of sediments as compared to channel sediments. The 239,240Pu deposition averaged 32 mCi km -2, which is higher than land-based fallout values of about 2 mCi km -2. The 239,240Pu to 137Cs ratio was about three times higher than fallout deposition estimates, indicating a more rapid desorption of 137Cs from sediment in the saline waters of the area.

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

    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 (similaritymetagenomic 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.

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

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

    2001-06-01

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

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

    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 μg/g dry weight, 16.0 μg/g dry weigh, 48.8 μg/g dry weight and 100.4 μg/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)

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

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

    2012-05-01

    A severe Cochlodinium geminatum red tide (>300 km2) was observed in the Zhujiang (Pearl) River estuary, South China Sea in autumn 2009. We evaluated the environmental conditions and phytoplankton community structure during the outbreak. The red tide water mass had significantly higher dissolved inorganic phosphate (DIP), ammonia, and temperature, but significantly lower nitrite, nitrate, dissolved inorganic nitrogen (DIN), and DIN/DIP relative to the non-red-tide zones. The phytoplankton assemblage was dominated by dinoflagellates and diatoms during the red tide. C. geminatum was the most abundant species, with a peak density of 4.13107 cell/L, accounting for >65% of the total phytoplankton density. The DIN/DIP ratio was the most important predictor of species, accounting for 12.45% of the total variation in the phytoplankton community. Heavy phosphorus loading, low precipitation, and severe saline intrusion were likely responsible for the bloom of C. geminatum.

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

    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.

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

    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.

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

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

    2013-12-01

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

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

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

    2013-01-01

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

  1. Seasonal change of community structure and size spectra of zooplankton in the Kaw River estuary (French Guiana)

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

    2006-06-01

    The zooplankton community of the Kaw River estuary in French Guiana and its relationship to its physical and chemical environment are described. Sampling was carried out in November 1998, June 1999, and November 2001, corresponding to the end of the dry season in 1998 and 2001 and to the end of the rainy season in 1999. The Kaw is a small coastal river that drains a vast swamp and flows into the Atlantic Ocean, close to the equator and to the mouth of the Amazon. The hydrodynamic and hydrochemical functioning of the estuary, and the development of littoral mangroves, is strongly constrained by the transport of sediments from the Amazon. During the rainy season the zooplankton, originating from the highly oligotrophic upstream sectors of the Kaw River, was of a strictly freshwater type. It was highly dispersed within the flooding water and dominated (in terms of density) by highly diversified rotifer taxa and (in terms of biomass) by cladocerans. During the dry season the estuary, turbid but enriched by exports from adjacent mudflats and mangroves, was colonized by a large and abundant zooplankton community that was dominated by tintinnids, with copepods as their main associated taxa. Exploiting the rich autochthonous phytoplankton and allochthonous phytobenthos, the microzooplankton components were only constrained when strong hydrodynamic exchanges allowed mixing between the opportunistic estuarine community and coastal mesozooplankton (copepods, chaetognaths, bivalve veligers). Between 1998 and 2001, these two communities were partially isolated from each other due to the gradual arrival of a mud bank, causing the blockage of the estuary. This isolation resulted in the under-exploitation of the microzooplankton. The intensification of tidal currents (spring tide) that occurred during the subsequent stabilization phase of the mudflat induced a more balanced zooplankton community. While the "estuarine" zooplankton of the Kaw River estuary therefore relies on the relative isolation of its water mass, its contribution to the coastal ecosystem also implies the existence of strong tidal currents that temporarily break this isolation.

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

    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.

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

    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.

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

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

    2008-12-01

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

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

    Thanomsak Boonphakdee

    2008-01-01

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

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

    Conrads, Paul A.; Roehl, Edwin A.; Daamen, Ruby C.; Cook, John B.; Sexton, Charles T.; Tufford, Daniel L.; Carbone, Gregory J.; Dow, Kristin

    2010-01-01

    The ability of water-resource managers to adapt to future climatic change is especially challenging in coastal regions of the world. The East Coast of the United States falls into this category given the high number of people living along the Atlantic seaboard and the added strain on resources as populations continue to increase, particularly in the Southeast. Increased temperatures, changes in regional precipitation regimes, and potential increased sea level may have a great impact on existing hydrological systems in the region. The Savannah River originates at the confluence of the Seneca and Tugaloo Rivers, near Hartwell, Ga., and forms the state boundary between South Carolina and Georgia. The J. Strom Thurmond Dam and Lake, located 238 miles upstream from the Atlantic Ocean, is responsible for most of the flow regulation that affects the Savannah River from Augusta, Ga., to the coast. The Savannah Harbor experiences semi-diurnal tides of two low and two high tides in a 24.8-hour period with pronounced differences in tidal range between neap and spring tides occurring on a 14-day and 28-day lunar cycle. Salinity intrusion results from the interaction of three principal forces - streamflow, mean tidal water levels, and tidal range. To analyze, model, and simulate hydrodynamic behaviors at critical coastal streamgages in the Lower Savannah River Estuary, data-mining techniques were applied to over 15 years of hourly streamflow, coastal water-quality, and water-level data. Artificial neural network (ANN) models were trained to learn the variable interactions that cause salinity intrusions. Streamflow data from the 9,850 square-mile Savannah River Basin were input into the model as time-delayed variables. Tidal inputs to the models were obtained by decomposing tidal water-level data into a “periodic” signal of tidal range and a “chaotic” signal of mean water levels. The ANN models were able to convincingly reproduce historical behaviors and generate alternative scenarios of interest. Important freshwater resources are located proximal to the freshwater-saltwater interface of the estuary. The Savannah National Wildlife Refuge is located in the upper portion of the Savannah River Estuary. The tidal freshwater marsh is an essential part of the 28,000-acre refuge and is home to a diverse variety of wildlife and plant communities. Two municipal freshwater intakes are located upstream from the refuge. To evaluate the impact of climate change on salinity intrusion on these resources, inputs of streamflows and mean tidal water levels were modified to incorporate estimated changes in precipitation patterns and sea-level rise appropriate for the Southeastern United States. Changes in mean tidal water levels were changed parametrically for various sea-level rise conditions. Preliminary model results at the U.S. Geological Survey (USGS) Interstate-95 streamgage (station 02198840) for a 7½-year simulation show that historical daily salinity concentrations never exceeded 0.5 practical salinity units (psu). A 1-foot sea-level rise (ft, 30.5 centimeters [cm]) would increase the number of days of salinity concentrations greater than 0.5 psu to 47 days. A 2-ft (61 cm) sea-level rise would increase the number of days to 248.

  7. Macrobenthos from unvegetated intertidal areas in the Caet river estuary in Bragana, Par

    Jos Souto Rosa Filho

    2006-12-01

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

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

    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.

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

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

  10. Estimates of bacterioplankton and Synechococcus spp. mortality from nanoflagellate grazing and viral lysis in the subtropical Danshui River estuary

    Tsai, An-Yi; Gong, Gwo-Ching; Huang, Yu Wen; Chao, Chien Fu

    2015-02-01

    To better understand picoplankton dynamics in the surface waters of upriver the Danshui River and its estuary, we assessed nanoflagellate-induced and virus-induced mortality of bacteria and Synechococcus spp. during different seasons (October, 2012 and January, April and July, 2013) using a modified dilution technique. Bacteria and viruses were significantly higher in abundance upriver than at the estuary. The distribution of Synechococcus spp. did not follow this spatial pattern. Abundance of Synechococcus spp. was relatively low during the whole sampling period in the upriver region. Furthermore, bacterial mortality resulting from nanoflagellate grazing were generally higher than those resulting from viral lysis in the upriver region, while Synechococcus spp. losses appeared to be mainly due to viral lysis upriver and in the estuary. Our dilution experiments suggested that nanoflagellates largely depend on bacteria as an important energy source there.

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

    Yin, Su; Wu, Yuehan; Xu, Wei; Li, Yangyang; Shen, Zhenyao; Feng, Chenghong

    2016-07-01

    To determine whether the discharge control of heavy metals in the Yangtze River basin can significantly change the pollution level in the estuary, this study analyzed the sources (upper river, the estuarine region, and the adjacent sea) of ten heavy metals (As, Cd, Co, Cr, Cu, Hg, Ni, Pb, Sb, and Zn) in dissolved and particulate phases in the surface water of the estuary during wet, normal, and dry seasons. Metal sources inferred from section fluxes agree with those in statistical analysis methods. Heavy metal pollution in the surface water of Yangtze Estuary primarily depends on the sediment suspension and the wastewater discharge from estuary cities. Upper river only constitutes the main source of dissolved heavy metals during the wet season, while the estuarine region and the adjacent sea (especially the former) dominate the dissolved metal pollution in the normal and dry seasons. Particulate metals are mainly derived from sediment suspension in the estuary and the adjacent sea, and the contribution of the upper river can be neglected. Compared with the hydrologic seasons, flood-ebb tides exert a more obvious effect on the water flow directions in the estuary. Sediment suspension, not the upper river, significantly affects the suspended particulate matter concentration in the estuary. PMID:27155472

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

    Huang, Dekun; Du, Jinzhou; Zhang, Jing

    2011-07-01

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

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

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

    2014-01-01

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

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

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

    2013-12-01

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

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

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

    2010-12-01

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

  16. Phylogenetic Analysis of Particle-Attached and Free-Living Bacterial Communities in the Columbia River, Its Estuary, and the Adjacent Coastal Ocean

    Crump, Byron C.; Armbrust, E. Virginia; Baross, John A.

    1999-01-01

    The Columbia River estuary is a dynamic system in which estuarine turbidity maxima trap and extend the residence time of particles and particle-attached bacteria over those of the water and free-living bacteria. Particle-attached bacteria dominate bacterial activity in the estuary and are an important part of the estuarine food web. PCR-amplified 16S rRNA genes from particle-attached and free-living bacteria in the Columbia River, its estuary, and the adjacent coastal ocean were cloned, and 2...

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

    Williams, Richard; Newman, Jonathan

    2006-01-01

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

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

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

    2006-12-01

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

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

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

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

    2002-01-01

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

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

    The Don River Estuary-Azov Sea system is an extension of the shallow continental shelf area of the Black Sea. A large data set of artificial radionuclides in bottom sediments of the Azov Sea has been compiled in order to examine the storage and migration of radionuclides within this highly restricted inland sea and to estimate the annual dose received by individuals in the local population who regularly consume fish. In recent years (1997-1999), the radionuclide content of surface sediments has been: 137Cs?0.5-100 Bq/kg d.w. (mean=33.825.9 Bq/kg d.w., n=57), 90Sr=0.2-5.7 Bq/kg d.w. (mean=2.11.4 Bq/kg d.w., n=34) and 239,240Pu=0.31-0.51 Bq/kg d.w. (n=2). In general, 137Cs activities increase with distance from the mouth of the Don River and correlate negatively with sediment grain size (r2=0.77, n=21). The annual 137Cs-derived dose received by an individual through the trophic chain water-fish-humans (?10-6 Sv/yr) is well below regulatory recommended limits, indicating that current levels of radioactivity in the environment pose no threat to commercial fisheries operations for the bordering nations of Russia and Ukraine

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

    Zheng, Senllin; Chen, Bin; Qiu, Xiaoyan; Chen, Meng; Ma, Zhiyuan; Yu, Xingguang

    2016-02-01

    To discover the distribution and risk of pesticides in Jiulong River and estuary, the residues of 102 pesticides were analyzed in water, sediment and clam samples collected from 35 sites in different seasons. A total number of 82 pesticides were detected and the occurrence and the risk to human and fish were assessed. Most of pesticides with high frequency were medium or low toxic except for DDTs. DDTs were the significant contaminant and the widely used dicofol was the new source of DDTs. The spatial and seasonal variation of pesticide distribution was linked with the distribution of orchards and farmlands. Health risk from river water consumption was low (RQ1) and 6 showed medium risk (0.1?QR<1). The single chemical posed high risk to fish included DDTs, triazophos, fenvalerate, bifenthrin and cyfluthrin, and those showed medium risk included dicofol, butachlor, isocarbophos, terbufos and cyhalothrin. There were 14 single pesticides detected with concentration above 100ngL(-1) in this study and the pesticide with the highest concentration was procymidone (3904ngL(-1)). Further experiments illustrated that procymidone could disrupt the expression of vitellogenin in the estuarine fish even at environmental concentrations. DDTs, dicofol, triazophos, isocarbophos, terbufos, cyfluthrin, bifenthrin, fenvalerate, cyhalothrin, butachlor and procymidone have become the significant pesticides and should be considered in aquatic ecosystem risk management. PMID:26461443

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

    Liu, Bo; de Swart, Huib E.

    2015-12-01

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

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

    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.

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

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

    2001-10-01

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

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

    Corbett, D. R.

    2010-10-01

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

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

    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.

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

    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.

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

    Kong, Fanzhou; Xu, Zijun; Yu, Rencheng; Yuan, Yongquan; Zhou, Mingjiang

    2016-01-01

    The Changjiang River estuary and adjacent waters are one of the most notable regions for red tides/harmful algal blooms in China's coastal waters. In this study, phytoplankton samples were collected and analyzed during the outbreak stage of red tides in May 2009. It was found that dinoflagellates, Prorocentrum donghaiense and Karenia mikimotoi, and diatoms, Skeletonema spp. and Paralia sulcata, were the major taxa dominating the phytoplankton community. Cluster analysis, non-metric multidimensional scaling (NMDS) and analysis of similarities (ANOSIM) was conducted on a data matrix including taxa composition and cell abundance of the phytoplankton samples. The analyses categorized the samples into three groups at a similarity level of 30%. Group I was characterized by estuarine diatoms and distributed mainly in the highly turbid estuarine region. Group II, which was dominated by the diatom Skeletonema spp. and represented the red tide of Skeletonema spp., was situated around Group I in the sea area west of 12250'E. Group III was characterized by a high proportion of dinoflagellates and was found further offshore compared with Groups I and II. Group III was further divided into two subgroups (III-S1 and III-S2) at a similarity level of 40%. Group III-S1 was characterized by the presence of the benthic diatom P. sulcata, representing phytoplankton samples collected either from the bottom or from the sea area affected by upwelling. Group III-S2 was dominated by dinoflagellates and represented red tides formed by P. donghaiense and K. mikimotoi. A gradual change of red-tide causative species was observed from the estuary to the offshore sea area, from diatoms to armored dinoflagellates and then unarmored dinoflagellates. Environmental factors associated with each group, and thus affecting the distribution of phytoplankton and red tides, are discussed.

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

    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).

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

    Acidity and leaching of metals from acid sulphate soils (ASSs) impair the water quality of receiving surface waters. The largest ASS areas in Europe are found in the coasts of the northern Baltic Sea. We used weight-of-evidence (WoE) approach to assess potential risks in 14 estuary sites affected by ASS in the Gulf of Finland, northern Baltic Sea. The assessment was based on exposure and effect profiles utilizing sediment and water metal concentrations and concurrent pH variation, sediment toxicity tests using the luminescent bacterium Vibrio fischeri and the midge Chironomus riparius, and the ecological status of benthic macroinvertebrate communities. Sediment metal concentrations were compared to national sediment quality criteria/guidelines, and water metal concentrations to environmental quality standards (EQSs). Hazard quotients (HQs) were established for maximum aluminium, cadmium and zinc concentrations at low pH based on applicable US EPA toxicity database. Sediment metal concentrations were clearly elevated in most of the studied estuaries. The EQS of cadmium (0.1 μg/l) was exceeded in 3 estuaries out of 14. The pH-minima were below the national threshold value (5.5) between good and satisfactory water quality in 10 estuaries. V. fischeri bioluminescence indicated toxicity of the sediments but toxic response was not observed in the C. riparius emergence test. Benthic invertebrate communities were deteriorated in 6 out of 14 sites based on the benthic invertebrate quality index. The overall ecotoxicological risk was assessed as low in five, moderate in three and high in five of the estuary sites. The risk assessment utilizing the WoE approach indicated that harmful effects of ASSs are likely to occur in the Baltic Sea river estuaries located at the ASS hotspot area. - Highlights: • Acid sulphate soils release high amounts of metals and acidity. • Metals and acidity are transported to estuary sites. • Acid sulphate soils impair the ecological status of several Baltic Sea estuaries. • More information is needed on low salinity estuaries

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

    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.

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

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

    2015-03-01

    Acidity and leaching of metals from acid sulphate soils (ASSs) impair the water quality of receiving surface waters. The largest ASS areas in Europe are found in the coasts of the northern Baltic Sea. We used weight-of-evidence (WoE) approach to assess potential risks in 14 estuary sites affected by ASS in the Gulf of Finland, northern Baltic Sea. The assessment was based on exposure and effect profiles utilizing sediment and water metal concentrations and concurrent pH variation, sediment toxicity tests using the luminescent bacterium Vibrio fischeri and the midge Chironomus riparius, and the ecological status of benthic macroinvertebrate communities. Sediment metal concentrations were compared to national sediment quality criteria/guidelines, and water metal concentrations to environmental quality standards (EQSs). Hazard quotients (HQs) were established for maximum aluminium, cadmium and zinc concentrations at low pH based on applicable US EPA toxicity database. Sediment metal concentrations were clearly elevated in most of the studied estuaries. The EQS of cadmium (0.1 μg/l) was exceeded in 3 estuaries out of 14. The pH-minima were below the national threshold value (5.5) between good and satisfactory water quality in 10 estuaries. V. fischeri bioluminescence indicated toxicity of the sediments but toxic response was not observed in the C. riparius emergence test. Benthic invertebrate communities were deteriorated in 6 out of 14 sites based on the benthic invertebrate quality index. The overall ecotoxicological risk was assessed as low in five, moderate in three and high in five of the estuary sites. The risk assessment utilizing the WoE approach indicated that harmful effects of ASSs are likely to occur in the Baltic Sea river estuaries located at the ASS hotspot area. - Highlights: • Acid sulphate soils release high amounts of metals and acidity. • Metals and acidity are transported to estuary sites. • Acid sulphate soils impair the ecological status of several Baltic Sea estuaries. • More information is needed on low salinity estuaries.

  14. A new species of Testudinella (Rotifera: Testudinellidae) From Qi’ao Island, Pearl River estuary, China

    Wei, N.; De Smet, W.H.; Xu, R.L.

    2010-01-01

    A new species of rotifer, Testudinella zhujiangensis sp. n. (Rotifera, Monogononta, Testudinellidae), is described from the littoral of an artificial brackish water lake and a mangrove swamp on Qi’ao Island of the Zhujiang/Pearl River estuary, Guangdong Province, south of China. It is closely related to Testudinella obscura ALTHAUS, 1957, but distinguished by its anterior truncated vase-shaped lorica, cross-sectional view, shallow inverted U-shaped foot opening, and small differences in the m...

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

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

    2009-01-01

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

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

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

    2015-01-01

    Lateral bays of the lower Columbia River estuary are areas of enhanced water retention that influence net ecosystem metabolism through activities of their diverse microbial communities. Metagenomic characterization of sediment microbiota from three disparate sites in two brackish lateral bays (Baker and Youngs) produced ∼100 Gbp of DNA sequence data analyzed subsequently for predicted SSU rRNA and peptide-coding genes. The metagenomes were dominated by Bacteria. A large component of Eukaryota...

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

    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

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

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

    2014-12-01

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

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

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

    2015-04-01

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

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

    Shen, Fang; Zhou, Yunxuan; Li, Jiufa; He, Qing; Verhoef, Wouter

    2013-10-01

    Satellite observation is an excellent tool for exploring the variability of the suspended sediment concentration (SSC) of turbid estuarine and coastal waters. We used a recently developed semi-empirical radiative transfer model combined with a multi-wavelength switching algorithm for the SSC retrieval from MEdium Resolution Imaging Spectrometer (MERIS) satellite data. This method can successfully retrieve SSC from satellite data in turbid estuarine and coastal waters with a wide range of sediment concentrations (20-2500 mg l-1) and is robust for quantifying realistic patterns of the surface sediment dynamics. The seasonal and annual variability of the MERIS-derived SSC from 2003 to 2010 were analysed in this work. Five regions-of-interest (ROIs) in the Yangtze estuary and coast are included in the analysis: the upper estuary, the lower estuary, the outer estuary, the Hangzhou Bay and the Qidong shore. The results reveal that the SSC of the upper estuary has significant seasonal and annual variations in response to seasonal cycling and annual fluctuation of the river discharge. A long-term continuing decrease of river discharge may cause an overall decline of the SSC in the entire estuary and adjacent areas. The existence of horizontal exchanges of the sediments between the Yangtze estuary and the Jiangsu coast implies that the decreased fluvial sediment loads of the estuary may partially be compensated by supplementing contributions from other origins.

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

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

    2010-12-01

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

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

    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

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

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

    2015-11-01

    Stock enhancement is increasingly proved to be an important measure of the fishery resources conservation, and the assessment of carrying capacity is the decisive factor of the effects of stock enhancement. Meanwhile, the variations in the energy flow patterns of releasing species and ecosystem were the basis for assessing carrying capacity of stock enhancement. So, in the present study, based on the survey data collected from the Yellow River estuary and adjacent waters during 2012-2013, three Ecopath mass-balance models were established in June, August and October, and the variations in ecosystem energy flow in these months were analyzed, as well as the assessment of carrying capacity of swimming crab enhancement. The energy flow mainly concentrated on trophic level I-III in Yellow River estuary and adjacent waters, and was relatively less on trophic level IV or above. The system flow proportion on the trophic level I was the highest in June, and was the lowest in August. The highest system flow proportion on the trophic level II was found in August, and the lowest in June. The relative and absolute energy flow of swimming crab mainly concentrated on the trophic level III, and the mean trophic level of swimming crab among June, August and October were 3.28. Surplus production was relatively higher in Yellow River estuary and adjacent waters, the highest value was found in June, and the lowest value in August. The ratios of total primary production/total respiration (TPP/TR) were 5.49, 2.47 and 3.01 in June, August and October, respectively, and the ratios of total primary production/total biomass (TPP/B) were 47.61, 33.30 and 29.78, respectively. Combined with the low Finn' s cycling index (FCI: 0.03-0.06), these changes indicated that the Yellow River estuary ecosystem was at an early development stage with higher vulnerability. The energy conversion efficiency of system was from 7.3% to 11.5%, the mean trophic levels of the catch were 3.23, 2.97 and 2.82 in June, August and October, respectively. The highest gross efficiency of the fishery was found in August, and the lowest in June. Finally, based on the Ecopath model in August survey, the preliminarily assessed carrying capacity of swimming crab was 1.5115 t · km(-2) in Yellow River estuary and adjacent waters. PMID:26915212

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

    Herfort, Lydie; Peterson, Tawnya D.; McCue, Lee Ann; Crump, Byron C.; Prahl, Fredrick G.; Baptista, Antonio M.; Campbell, Victoria; Warnick, Rachel; Selby, Mikaela; Roegner, G. Curtis; Zuber, Peter A.

    2011-01-04

    For at least a decade, annually recurring blooms of the photosynthetic ciliate, Myrionecta rubra have been observed in the Columbia River estuary in late summer. In an effort to understand the dynamics of these blooms, we investigated the genetic variability of M. rubra and its cryptophyte plastids within three large estuarine blooms formed in consecutive years (2007-2009), and conducted a broader spatial survey along the coasts of Oregon/Washington. Analysis of the ‘18S-28S’ sequences specific for Mesodiniidae uncovered at least 7 variants of M. rubra within the Columbia River coastal margin in spring and summer, but only one of these M. rubra variants was implicated in estuary bloom formation. Using a multigene approach, we show that the bloom-forming variant of M. rubra appears to harbor the same cryptophyte chloroplast in recurring blooms. Analyses of chloroplast 16S rRNA, cryptophyte RuBisCO and Photosystem II D2 genes together suggest that the plastid is derived from Teleaulax amphioxeia. Free-living cells of this species and of other cryptophytes were practically absent from the bloom patches in the estuary main channels based on 18S rDNA sequence analyses. The respectively low and high proportions of T. amphioxeia nuclei and chloroplasts signals found in the M. rubra bloom of the Columbia River estuary in successive years supports the notion of a transient association between T. amphioxeia and the bloom-forming M. rubra variant, with loss of cryptophyte nuclei. The genetic variability of M. rubra uncovered here is relevant to the controversy in the literature regarding the cryptophyte /M. rubra association.

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

    Chen, XinJian

    2012-06-01

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

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

    Shan, Xiujuan; Jin, Xianshi; Yuan, Wei

    2010-05-01

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

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

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

    2008-04-15

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

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

    Coastal marine resources are at risk from anthropogenic contaminants, including legacy persistent organic pollutants (POPs) with half-lives of decades or more. To determine if polychlorinated biphenyl (PCB) signatures can be used to distinguish among local populations of inshore bottlenose dolphins (Tursiops truncatus) along the southeastern U.S. coast, blubber from free-ranging and stranded animals were collected along the Georgia coast in 2004 and analyzed for PCB congeners using gas chromatography with electron capture and negative chemical ionization mass spectrometric detection (GC-ECD and GC-NCI-MS). Mean total PCB concentrations (77 ± 34 μg/g lipid) were more than 10 fold higher and congener distributions were highly enriched in Cl7-Cl10 homologs in free-ranging animals from the Turtle/Brunswick River estuary (TBRE) compared with strandings samples from Savannah area estuaries 90 km to the north. Using principal components analysis (PCA), the Aroclor 1268 signature associated with TBRE animals was distinct from that observed in Savannah area animals, and also from those in animals biopsied in other southeastern U.S estuaries. Moreover, PCB signatures in dolphin blubber closely resembled those in local preferred prey fish species, strengthening the hypothesis that inshore T. truncatus populations exhibit long-term fidelity to specific estuaries and making them excellent sentinels for assessing the impact of stressors on coastal ecosystem health

  9. 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

    Hongyan Xi; Yuanzhi Zhang; Yunpeng Wang; Yufei Wang

    2009-01-01

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

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

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

    2009-08-02

    This work focuses on the numerical modeling of Columbia River estuarine circulation and associated modeling-supported analyses conducted as an integral part of a multi-disciplinary and multi-institutional effort led by NOAA's Northwest Fisheries Science Center. The overall effort is aimed at: (1) retrospective analyses to reconstruct historic bathymetric features and assess effects of climate and river flow on the extent and distribution of shallow water, wetland and tidal-floodplain habitats; (2) computer simulations using a 3-dimensional numerical model to evaluate the sensitivity of salmon rearing opportunities to various historical modifications affecting the estuary (including channel changes, flow regulation, and diking of tidal wetlands and floodplains); (3) observational studies of present and historic food web sources supporting selected life histories of juvenile salmon as determined by stable isotope, microchemistry, and parasitology techniques; and (4) experimental studies in Grays River in collaboration with Columbia River Estuary Study Taskforce (CREST) and the Columbia Land Trust (CLT) to assess effects of multiple tidal wetland restoration projects on various life histories of juvenile salmon and to compare responses to observed habitat-use patterns in the mainstem estuary. From the above observations, experiments, and additional modeling simulations, the effort will also (5) examine effects of alternative flow-management and habitat-restoration scenarios on habitat opportunity and the estuary's productive capacity for juvenile salmon. The underlying modeling system is part of the SATURN1coastal-margin observatory [1]. SATURN relies on 3D numerical models [2, 3] to systematically simulate and understand baroclinic circulation in the Columbia River estuary-plume-shelf system [4-7] (Fig. 1). Multi-year simulation databases of circulation are produced as an integral part of SATURN, and have multiple applications in understanding estuary/plume variability, the role of the estuary and plume on salmon survival, and functional changes in the estuary-plume system in response to climate and human activities.

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

    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.

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

    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

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

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

    1987-08-01

    This study was designed to relate fauna characteristics and sediment accumulation processes in the James River, VA and was conducted during June 1981. Physical sedimentary and benthic biological parameters, as well as sediment structure and radionuclide profiles, were evaluated for 11 stations. Faunal distribution patterns reflected species' response to salinity changes along the estuarine gradient, but not to differences in sediment accumulation rates. Levels of bioturbation could not be predicted easily on the basis of faunal characteristics alone. Results suggest that the physical processes of erosion and deposition strongly influence the ability of macrobenthos to bioturbate sediments in this estuary. Areas of rapid deposition (>3 cm y -1) exhibit little evidence of bioturbation, as do areas where erosion, or relatively constant physical reworking of sediments, dominate. Areas with low sediment accumulation rates (05-3 cm y -1) exhibit the highest levels of mixing as evidenced in X-radiographs. Estuarine organisms inhabiting soft bottoms are typically 'opportunistic', shallow-living and short-lived species, and the composition of their communities is not strongly influenced by rates of deposition. Physical reworking of sediments is most likely to occur near to the sediment-water interface where reworking by shallow-living organisms is most intense. Sediment-mixing processes should be characterized using a range of approaches. The phasing of interactions among erosion, physical transport, deposition and biological mixing must be resolved on the appropriate time scales if the mechanics of processes governing the formation of the sedimentary record are to be elucidated.

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

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

    2015-12-01

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

  15. Mitochondrial genome sequence of Paramisgurnus dabryanus from the Yellow River estuary: implication for Cobitidae phylogeny.

    Zhu, Ming; Liu, Feng

    2016-07-01

    Paramisgurnus dabryanus Sauvage (Cobitidae, Cypriniformes) is a native large-scale loach widely distributed in main inland freshwater systems of China. The complete mitochondrial genome sequence of P. dabryanus from the Yellow River (YR) estuary was characterized in the present study. The circular mitogenome is 16 570 bp in size and contains two ribosomal RNA genes, 22 transfer RNA genes, and 13 protein-coding genes. The overall A + T content is 56.64% in the range of other Cobitidae studied. The mitogenome of P. dabryanus YR has an overall nucleotide sequence identity of 96.9% with that from Zhejiang, and 89.2% with that from Hubei. All the Misgurnus and Paramisgurnus species were clustered into two Misgurnus/Paramisgurnus complex clades with high bootstrap values based on the whole mitogenome sequences. The mitochondrial phylogenomic analysis indicates that the relationships in Cobitidae are inconsistent with the current classification system and taxonomic revision is required on the basis of molecular phylogeny and morphology. PMID:26162049

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

    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.

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

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

    2015-11-01

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

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

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

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

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

    2015-11-01

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

  20. Distributions and sources of polycyclic aromatic hydrocarbons in surface sediments from the Cross River estuary, S.E. Niger Delta, Nigeria.

    Ekpo, Bassey Offiong; Oyo-Ita, Orok E; Oros, Daniel R; Simoneit, Bernd R T

    2012-01-01

    Polycyclic aromatic hydrocarbon (PAH) analyses of surface sediments from the Cross River estuary by gas chromatography-mass spectrometry indicated natural diagenetically derived PAHs in the upper estuary, with minor and variable amounts of petrogenic and combustion-derived PAHs from human activities (lower estuary). The occurrence of significant amounts of perylene (average 23% of all PAHs) with the diagenetic natural PAHs in the middle estuary bordered by mangrove forests supports its origin from terrestrial organic matter. The natural PAHs represent the highest percentage (average 76%) of the total PAHs in this tropical environment. The traditional geochemical parameters, including the petrogenic PAHs, confirmed trace petroleum contamination in the estuary. Specific PAH ratios such as Fl/Py and Fl/(Fl+Py) also support this source contribution. PMID:21472387

  1. Occurrences of Salmonella spp. in water and soil sample of the Karnafuli river estuary

    Mohammad Zafar

    2012-12-01

    Full Text Available This study was carried out to examine the presence of Salmonella spp. in soil and water sample along with some physio-chemical parameters of water at the Karnafuli river estuary during March-June 2012 from 3 stations. The ranges of measured parameters of water samples were 26.5- 32ºC, 0.0 – 5.0‰, 7.5 – 7.9 and 2.28 – 2.91mg/l for temperature, salinity, pH and dissolved oxygen (DO, respectively.. In the present investigation, it was observed that the values of physio chemical parameters in the estuarine area were fluctuated seasonally. Water temp, salinity and pH were within acceptable range according to EQSBand guidelines value of WHO but the concentration of DO decreased significantly indicating the deterioration of estuarine environment including water quality and soil conditions which are influenced by higher bacterial growth in the polluted estuarine zone. MaximumSalmonella spp. concentrations were observed 5cells/ml in soil from one station (St-1 out of 3 total sampling stations during the month of May. The occurrences of Salmonella spp. was not found many of the stations they were absent. Considering the prevailing physio-chemicalparameters and bacteriological conditions as detected in this study in the Karnafuli river estuarine water and soil, it appears that the estuarine environment including the water and soils were polluted. Such contaminated water is not suitable for household uses and possibly hazardous to many aquatic animals and human health.

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

    L. C. Bruce

    2013-07-01

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

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

    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.

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

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

    2011-07-01

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

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

    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 sediments

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

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

    2015-01-15

    Coastal areas are subject to a great anthropogenic pressure because more than half of the world's population lives in its vicinity causing organic matter inputs, which intensifies greenhouse gas emissions into the atmosphere. Dissolved concentrations of CH4 and N2O have been measured seasonally during 2013 in the Guadalete River Estuary, which flows into the Cadiz Bay (southwestern Spanish coast). It has been intensely contaminated since 1970. Currently it receives wastewater effluents from cities and direct discharges from nearby agriculture crop. Eight sampling stations have been established along 18 km of the estuary. CH4 and N2O were measured using a gas chromatograph connected to an equilibration system. Additional parameters such as organic matter, dissolved oxygen, nutrients and chlorophyll were determinate as well, in order to understand the relationship between physicochemical and biological processes. Gas concentrations increased from the River mouth toward the inner part, closer to the wastewater treatment plant discharge. Values varied widely within 21.8 and 3483.4 nM for CH4 and between 9.7 and 147.6 nM for N2O. Greenhouse gas seasonal variations were large influenced by the precipitation regime, masking the temperature influence. The Guadatete Estuary acted as a greenhouse gas source along the year, with mean fluxes of 495.7 ?mol m(-2)d(-1) and 92.8 ?mol m(-2)d(-1) for CH4 and N2O, respectively. PMID:24993513

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

    Cheng, Fangjin; Yu, Zhiming; Song, Xiuxian

    2014-01-01

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

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

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

    2015-09-01

    In this study, we present comprehensive data on dissolved Ca, dissolved inorganic carbon (DIC) and its carbon isotope composition (?13CDIC) of (i) the Ganga (Hooghly) River estuary water sampled during six seasons of contrasting water discharge over 2 years (2012 and 2013), (ii) shallow groundwater from areas adjacent to the estuary and (iii) industrial effluent water and urban wastewater draining into the estuary. Mass balance calculations indicate that processes other than the conservative mixing of seawater and river water are needed to explain the measured DIC and ?13CDIC. Results of mixing calculations in conjunction with the estimated undersaturated levels of dissolved O2 suggest that biological respiration and organic carbon degradation dominate over biological production in the estuary. An important outcome of this study is that a significant amount of DIC and dissolved Ca is produced within the estuary at salinity ?10, particularly during the monsoon period. Based on consideration of mass balance and a strong positive correlation observed between the "excess" DIC and "excess" Ca, we contend that the dominant source of DIC generated within the estuary is carbonate dissolution that is inferred to be operating in conjunction with degradation of organic carbon. Calculations show that groundwater cannot account for the observed "excess" Ca in the high salinity zone. Estimated DIC contributions from anthropogenic activity are minor, and they constitute ca. 2-3% of the river water DIC concentrations. The estimated annual DIC flux from the estuary to the Bay of Bengal is ca. (3-4) 1012 g, of which ca. 40-50% is generated within the estuary. The monsoon periods account for the majority (ca. 70%) of the annual DIC generation in the estuary. The annual DIC flux from the Hooghly estuary accounts for ca. 1% of the global river DIC flux to the oceans. This is disproportionately higher than the water contribution from the Hooghly River to the oceans, which accounts for ca. 0.2% of the global river water flux. The results of this study suggest that estuaries in regions affected by tropical monsoon can be important in terms of their production of significant amounts of DIC and its delivery to the world's oceans.

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

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

  10. 76 FR 8345 - Endangered and Threatened Species; Recovery Plan Module for Columbia River Estuary Salmon and...

    2011-02-14

    ... comments on the Proposed Estuary Module was published in the Federal Register on January 8, 2008 (73 FR 161... by sediment. using dredged materials beneficially. CRE-8: Remove or modify pilings and pile dikes... jurisdictions and domains, NMFS recognized the need for consistent treatment of the factors in the estuary...

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

    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.

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

    Elaine Bernini

    2014-03-01

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

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

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

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

    G.-L. Zhang

    2010-11-01

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

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

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

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

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

    2015-12-01

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

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

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

    2015-02-01

    Dissolved aluminum (Al) is a sensitive tracer for biogeochemical cycles in the ocean. There has been a dramatic decline in water and sediment fluxes into the sea from the Huanghe because of climate change and human activities. Water-Sediment Regulation Schemes (WSRSs) have been implemented annually to flush trapped sediments from the upstream watercourse and reservoirs of the river. Monthly observations to investigate the behavior of dissolved Al in the lower reach of the Huanghe were carried out from November 2008 to December 2010. During 2009, daily observations were made to assess the impact of the ninth WSRS on the lower reach of the Huanghe and three cruises were carried out in the Huanghe Estuary in 2009 (prior to, during and following the WSRS). The monthly concentrations of dissolved Al ranged from 25 nM to 362 nM (average 90 nM) in the lower reach of the Huanghe. Assessment of the seasonal variation of dissolved Al showed that the highest concentrations occurred in summer and the lowest in winter: these corresponded to the variations in water discharge and sediment loads, which were controlled by WSRS events. During the ninth WSRS events in 2009 the daily runoff and sediment load increased from 200 m3/s to 3600 m3/s and from 0.1 g/L to 5 g/L, respectively. The concentration of dissolved Al increased from 180 nM to 600 nM (average 380 nM) in less than 20 days, which were equivalent to 43% of the annual Al flux into the Bohai. Exchange between dissolved and particulate Al, investigated using a simple sorption model based on the distribution coefficient (Kd), was approximately 106 mL/g in the Huanghe. The average concentrations of dissolved Al in the Huanghe Estuary prior to, during and following the WSRS were 243 nM, 238 nM and 186 nM, respectively. The comparable concentrations of dissolved Al in the Huanghe Estuary prior to and during the WSRS indicate that removal processes occurred in the initial stages of mixing in the estuary. The Al-salinity relationship and laboratory mixing experiments demonstrated that dissolved Al has a non-conservative behavior in the Huanghe Estuary, where a significant loss (20-50%) occurred. The mechanism of removal of dissolved Al in the Huanghe Estuary was adsorption onto suspended particulate matter and salt-induced flocculation. These observations suggest that human activities (e.g. the WSRSs) and sorption processes dominate the geochemical interactions of Al in the Huanghe and its estuary.

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

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

    2011-01-01

    Over the past two decades China has become the largest global consumer of fertilizers, which has enhanced river nutrient fluxes and caused eutrophication and hypoxia in the Yangtze (Changjiang) large river delta-front estuary (LDE). In this study, we utilized plant pigments, lignin-phenols, stable isotopes (δ13C and δ15N) and foraminiferal microfossils in 210Pb dated cores to examine the history of hypoxia in the Changjiang LDE. Two sediment cores were collected onboard R/V Dong Fang Hong 2 using a stainless-steel box-corer; one at a water depth of 24.7 m on Jun. 15, 2006 and the other at 52 m on Nov. 20, 2007, both in the hypoxic region off the Changjiang LDE. There has been a significant increase in the abundance of plant pigments after 1979 that are indicators of enhanced diatom and cyanobacterial abundance, which agrees with post-1980 record of increasing nutrient loads in the Changjiang River. The increased inputs of terrestrially derived materials to the LDE are largely woody plant sources and most likely due to deforestation that began in the early 1950s. However, post-1960 lignin data did not reflect enhanced loading of woody materials despite continued deforestation possibly due to increased trapping from greater dam construction, a reduction of deforestation in the drainage basin since the last 1990s, and soil conservation practices. The lack of linkages between bulk indices (stable isotopes, % OC, molar C/N ratios) and microfossil/chemical biomarkers may reflect relative differences in the amount of carbon tracked by these different proxies. Although NO3− is likely responsible for most of the changes in phytoplankton production (post 1970s), historical changes in N loading from the watershed and hypoxia on the LDE shelf may not be as well linked in East China Sea (ECS) sediments due to possible denitrification/ammonification processes; finally, increases in low-oxygen tolerant foraminiferal microfossils indicate there has been an increase in the number of hypoxic bottom water events on the Changjiang LDE over the past 60 years.

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

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

    1984-01-01

    A wide variety of sedimentary subenvironments are found within a 10-km stretch of James River including a flood dominated channel (Rocklanding Channel) and its bank (Rocklanding Shoal), a shoal with a water depth of 1 m separating two channels (Point of Shoals), an ebb-dominated channel (Burwell Bay Channel) and its bank (Burwell Bay Bank) and a tributary (Warwick River). The concentrations of Cs-137, Cu, Pb, Zn and organic carbon in the fine-grained sediments (i.e. Cs-137 geochronology, range from 04 to > 3 cm year -1. The sedimentation rates in the Burwell Bay region are two or more, times those in the Point of Shoals and in the Rocklanding Channel and Shoal, reflecting the weaker currents in the Burwell Bay region. These sedimentation rates agree well with those obtained independently by measuring changes in the bathymetry of this area between 1873 and 1943. The concentrations of Cs-137, Cu, Pb, Zn and organic carbon in surface sediments vary by a factor of two to three. The concentrations are higher in the Burwell Bay region, probably as a result of the higher rates of accumulation of recently formed sediments in these subenvironments. The inventories of fine-grained sediments and of Cs-137, Cu, Pb, Zn and organic carbon accumulated since 1954 are also up to an order of magnitude higher in the Burwell Bay region. Although the concentrations of fine-grained sediments in three cores obtained in this region are similar, the inventories still vary by a factor of two to three. The inventories of Cs-137, Cu, Pb, Zn, organic carbon and fine-grained sediments correlate well with each other indicating that Cs-137 can be a useful tracer for studying the fate of these metals and organic carbon in estuarine environments. The inhomogeneity of the concentrations and inventories of the different elements along a 10-km segment of a river suggests that a closely-spaced sampling programme is essential for characterizing the sedimentary provinces within an estuary. The concentrations of Cs-137, metals and organic carbon in the coarse-grained sediments (i.e. > 63 ?m) are considerably lower than those in fine-grained sediments. Thus, the contribution of coarse-grained sediments to the total inventory of these elements is small.

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

    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.

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

    Pang, A. P.; Sun, T.

    2014-05-01

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

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

    Tim Webster

    2014-03-01

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

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

    Sengupta, Anjan; Chaudhuri, Subhendu

    2002-08-01

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

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

    Ma, Zhijun; Wang, Yong; Gan, Xiaojing; Li, Bo; Cai, Yinting; Chen, Jiakuan

    2009-06-01

    We studied the changes in wetland habitats and waterbird communities between the 1980s and the 2000s at Chongming Dongtan, a Ramsar site in the Yangtze River estuary, an ecologically important region. This region is an important stopover site for shorebirds along the East Asian-Australasian flyway and is extensively used by waterfowl. A net loss of 11% of the wetland area was estimated during study periods at Chongming Dongtan. The change was dependent on wetland types: while the area of artificial habitats such as paddy fields and aquacultural ponds more than doubled, more than 65% of natural habitats including sea bulrush ( Scirpus mariqueter) and common reed ( Phragmites australis) marshes were lost over the two decades. An exotic plant species introduced from North America, smooth cordgrass ( Spartina alterniflora), occupied 30% of the vegetated intertidal zone by the 2000s. Although waterbird species richness did not change between the 1980s (110) and the 2000s (111), 13 species found in 1980s were replaced by 14 newly recorded species. Moreover, there were more species with declining trends (58) than with increasing trends (19). The population trends of species were affected by residential status and habitat types. Transients, wintering migrants, and habitat specialists were more likely to show declining trends compared to those breeding at Dongtan (including year-round and summer residents) and habitat generalists. Furthermore, species associated mainly with natural wetlands were more likely to decline than those associated mainly with artificial wetlands. These patterns suggest that the loss and change of wetland habitats at Chongming Dongtan adversely affected local population dynamics and might have contributed to the global decline of some waterbird species. Because Chongming Dongtan provides stopover and wintering habitats for many migratory waterbirds, protection and restoration of natural wetlands at Chongming Dongtan are urgently needed.

  5. Use of fishing resources by women in the Mamanguape River Estuary, Paraba state, Brazil

    Michelle S.P. Rocha

    2012-12-01

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

  6. Osprey: worldwide sentinel species for assessing and monitoring environmental contamination in rivers, lakes, reservoirs, and estuaries.

    Grove, Robert A; Henny, Charles J; Kaiser, James L

    2009-01-01

    In the United States, many fish and wildlife species have been used nationwide to monitor environmental contaminant exposure and effects, including carcasses of the bald eagle (Haliaeetus leucocephalus), the only top avian predator regularly used in the past. Unfortunately, bald eagles are sensitive to investigator intrusion at the nest. Thus, the osprey (Pandion haliaetus) is evaluated as a potential sentinel species for aquatic ecosystems. Several characteristics support the choice of the osprey as a sentinel species, including: (1) fish-eating diet atop the aquatic food web, (2) long-lived with strong nest fidelity, (3) adapts to human landscapes (potentially the most contaminated), (4) tolerates short-term nest disturbance, (5) nests spatially distributed at regular intervals, (6) highly visible nests easily located for study, (7) ability to accumulate most, if not all, lipophilic contaminants, (8) known sensitivity to many contaminants, and (9) nearly a worldwide distribution. These osprey traits have been instrumental in successfully using the species to understand population distribution, abundance, and changes over time; the effects of various contaminants on reproductive success; how contaminants in prey (fish on biomass basis) contribute to egg concentrations (i.e., biomagnification factors); and spatial residue patterns. Data summarized include nesting population surveys, detailed nesting studies, and chemical analyses of osprey egg, organ, blood, and feather samples for contaminants that bioaccumulate and/or biomagnify in aquatic food webs; and biochemical evaluations of blood and various organs. Studies in the United States, Canada, Mexico, Europe, and elsewhere have shown the osprey to be a useful sentinel species for monitoring selected environmental contaminants, including some emerging contaminants in lakes, reservoirs, rivers, and estuaries. PMID:19117208

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

    Ma, Zhijun; Wang, Yong; Gan, Xiaojing; Li, Bo; Cai, Yinting; Chen, Jiakuan

    2009-06-01

    We studied the changes in wetland habitats and waterbird communities between the 1980s and the 2000s at Chongming Dongtan, a Ramsar site in the Yangtze River estuary, an ecologically important region. This region is an important stopover site for shorebirds along the East Asian-Australasian flyway and is extensively used by waterfowl. A net loss of 11% of the wetland area was estimated during study periods at Chongming Dongtan. The change was dependent on wetland types: while the area of artificial habitats such as paddy fields and aquacultural ponds more than doubled, more than 65% of natural habitats including sea bulrush (Scirpus mariqueter) and common reed (Phragmites australis) marshes were lost over the two decades. An exotic plant species introduced from North America, smooth cordgrass (Spartina alterniflora), occupied 30% of the vegetated intertidal zone by the 2000s. Although waterbird species richness did not change between the 1980s (110) and the 2000s (111), 13 species found in 1980s were replaced by 14 newly recorded species. Moreover, there were more species with declining trends (58) than with increasing trends (19). The population trends of species were affected by residential status and habitat types. Transients, wintering migrants, and habitat specialists were more likely to show declining trends compared to those breeding at Dongtan (including year-round and summer residents) and habitat generalists. Furthermore, species associated mainly with natural wetlands were more likely to decline than those associated mainly with artificial wetlands. These patterns suggest that the loss and change of wetland habitats at Chongming Dongtan adversely affected local population dynamics and might have contributed to the global decline of some waterbird species. Because Chongming Dongtan provides stopover and wintering habitats for many migratory waterbirds, protection and restoration of natural wetlands at Chongming Dongtan are urgently needed. PMID:19139954

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

    Guo, Yanwei; Yang, Shouye

    2015-06-01

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

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

    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.

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

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

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

    Sohair A. Mostafa; Maha A. Hewedy; Hussein; E. Touliabah; Sanaa; Ashour, M; Abdallah, Soad A

    2003-01-01

    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 w...

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

    Li, MS; Lee, SY

    1998-01-01

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

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

    Khwanruan Srinui; Shuhei Nishida; Susumu Ohtsuka

    2013-01-01

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

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

    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.

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

    Christina Vinson

    2004-01-01

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

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

    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 ...

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

    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)

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

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

    2002-12-01

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

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

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

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

    Jos Mauro, Sterza; Luiz Loureiro, Fernandes.

    2006-12-01

    Full Text Available O presente estudo teve como objetivo caracterizar a comunidade zooplanctnica de cladceros no esturio do Rio Paraba do Sul, localizado no municpio de So Joo da Barra, RJ. O zooplncton foi coletado mensalmente de setembro/2002 a agosto/2003 em nove estaes atravs de arrastos subsuperficiais [...] com uma rede de plncton com abertura de boca de 30 cm e malha de 70 m, dotada de fluxmetro mecnico. Foram medidas simultaneamente a salinidade e a temperatura. Foram identificadas dezessete espcies de cladceros: 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 abundncias de cladceros ocorreram no ms de abril na zona marinha do esturio. A espcie mais abundante nesse perodo foi Penilia avirostris. Na zona de mistura e fluvial do esturio, as espcies mais abundantes foram Moina micrura, principalmente durante o ms de janeiro; Simocephalus vetalus e Bosmina longirostris na primavera. Diante desse cenrio, pode-se dizer que a comunidade de cladceros no esturio do Rio Paraba do Sul apresenta caractersticas de ambientes marinhos, estuarinos e limnicos. A salinidade e a temperatura parecem limitar a ocorrncia e distribuio dos cladceros no esturio. Abstract in english To characterize the cladoceran community of the Paraba do Sul River estuary, located in the district of So Joo 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 Paraba 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.

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

    Jos Mauro Sterza

    2006-12-01

    Full Text Available To characterize the cladoceran community of the Paraba do Sul River estuary, located in the district of So Joo da Barra, Rio de Janeiro, Brazil, cladocerans were collected monthly in nine sampling stations from September 2002 until August 2003. Samples were obtained by subsurface tows using a plankton net with a 30 cm opening mouth and 70 micron mesh size, fitted with a mechanical flowmeter. Environmental parameters such as salinity and temperature were also obtained. Seventeen species of Cladocera were identified: Pseudoevadne tergestina, Penilia avirostris, Macrothrix triserialis, Moina micrura, Simocephalus kerhervei, Simocephalus vetalus, Simocephalus latirostris, Simocephalus serrulatus, Alona rectangula, Alona quadrangularis, Bosmina longirostris, Bosminopsis deitersi, Camptocercus dadayi, Ceriodaphnia richardi, Diaphanosoma fluviatile, Kurzia latissima and Pleuroxus similis. The highest total abundance of Cladocera occurred in April in the marine zone of the estuary. The most abundant species during this period was Penilia avirostris. At the mixing and freshwater zones of the estuary, the most abundant species were Moina micrura, mainly in January; and Simocephalus vetalus and Bosmina longirostris during spring. From this scenario, it can be inferred that the cladoceran community of the Paraba do Sul River estuary presents characteristics of marine, brackish and freshwater environments. Temperature and salinity seem to limit the occurrence and distribution of cladocerans in the estuary.O presente estudo teve como objetivo caracterizar a comunidade zooplanctnica de cladceros no esturio do Rio Paraba do Sul, localizado no municpio de So Joo da Barra, RJ. O zooplncton foi coletado mensalmente de setembro/2002 a agosto/2003 em nove estaes atravs de arrastos subsuperficiais com uma rede de plncton com abertura de boca de 30 cm e malha de 70 m, dotada de fluxmetro mecnico. Foram medidas simultaneamente a salinidade e a temperatura. Foram identificadas dezessete espcies de cladceros: 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 abundncias de cladceros ocorreram no ms de abril na zona marinha do esturio. A espcie mais abundante nesse perodo foi Penilia avirostris. Na zona de mistura e fluvial do esturio, as espcies mais abundantes foram Moina micrura, principalmente durante o ms de janeiro; Simocephalus vetalus e Bosmina longirostris na primavera. Diante desse cenrio, pode-se dizer que a comunidade de cladceros no esturio do Rio Paraba do Sul apresenta caractersticas de ambientes marinhos, estuarinos e limnicos. A salinidade e a temperatura parecem limitar a ocorrncia e distribuio dos cladceros no esturio.

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

    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.

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

    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)

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

    Jenkins, D. W.

    1972-01-01

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

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

    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

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

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

    2015-08-01

    The combined studies on grain size distribution, organic matter contents of sediments, sequential extraction and bulk concentration of heavy metals, statistical analysis, and ecological risk assessments were carried out to investigate the contamination sources and ecological risks of surface sediments at Coleroon River Estuary in Tamil Nadu, India. The sequential extraction of metals showed that a larger portion of the metals was associated with the residual phase and also in other fractions. The low concentrations of heavy metals were found in exchangeable and carbonate bounds (bioavailable phases). It revealed that sediments of Coleroon River Estuary were relatively unpolluted and were influenced mainly by natural sources. The observed order of bulk concentrations of heavy metals in the sediments was as follows: Fe > Mn > Zn > Cu > Pb > Cr > Ni > Co. Factor analyses represented that the enrichment of heavy metals was mostly resulted from lithogenic origins associated with anthropogenic sources. These sources were reconfirmed by cluster analysis. Risk assessment code (RAC) suggested that all metals were not harmful in monsoon season. However, Fe was in medium risk, and Mn and Cu were in low risk in summer. According to pollution load index (PLI) of sediments, all heavy metals were toxic. Cu might be related with adverse biological effects on the basis of sediment quality guidelines (SQG) in both seasons. These integrated approaches were very useful to identify the contamination sources and ecological risks of sediments in estuarine environment. It is expected that this research can give a useful information for the remediation of heavy metals in sediments. PMID:26178040

  7. Temporal and spatial distribution of red tide outbreaks in the Yangtze River Estuary and adjacent waters, China.

    Liu, Lusan; Zhou, Juan; Zheng, Binghui; Cai, Wenqian; Lin, Kuixuan; Tang, Jingliang

    2013-07-15

    Between 1972 and 2009, evidence of red tide outbreaks in the Yangtze River Estuary and adjacent waters was collected. A geographic information system (GIS) was used to analyze the temporal and spatial distribution of these red tides, and it was subsequently used to map the distribution of these events. The results show that the following findings. (1) There were three red tide-prone areas: outside the Yangtze River Estuary and the eastern coast of Sheshan, the Huaniaoshan-Shengshan-Gouqi waters, and the Zhoushan areas and eastern coast of Zhujiajian. In these areas, red tides occurred 174 total times, 25 of which were larger than 1000 km(2) in areal extent. After 2000, the frequency of red tide outbreaks increased significantly. (2) During the months of May and June, the red tide occurrence in these areas was 51% and 20%, respectively. (3) Outbreaks of the dominant red tide plankton species Prorocentrum dong-haiense, Skeletonema costatum, Prorocentrum dantatum, and Noctiluca scientillan occurred 38, 35, 15, and 10 times, respectively, during the study interval. PMID:23628547

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

    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.

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

    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.

  10. An experimental transplantation to select the optimal site for restoration of the eelgrass Zostera marina in the Taehwa River estuary

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

    2013-12-01

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

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

    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)

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

    Sanders, Tina; Dhnke, Kirstin

    2014-05-01

    Estuaries act as a nutrient filter for coastal waters. The eutrophic Elbe River estuary is loaded with fertilizer-derived nitrogen, but management efforts have started to reduce this load effectively. However, an internal nitrate source in turn gained in importance and the estuary changed from a sink to a source of reactive nitrogen. Nitrification plays a key role in this estuarine nutrient regeneration but has to be quantified. The aim of our study was to assess the impact of nitrification on seasonal nitrogen loads and turnover using stable N- isotopes to identify the natural fractionation factor of nitrification. Therefor we measured the dissolved inorganic nitrogen (ammonium, nitrite and nitrate), their stable isotope signatures and the in-situ nitrification rates in the tidal influenced part of the river during 9 cruises from August 2011 to August 2013. The DIN load was higher in winter than in summer, the main compound was nitrate. In summer concentrations of nitrate entering the estuary were between 50 and 100 ?M and ?15N and ?18O were enriched to 15.5 to 21.5 o and 7.5 to 11.5 o respectively. Strong nitrification was found in the Hamburg port region. The nitrate concentrations increased significantly downstream after the port of Hamburg, along with a decrease of isotope values. Ammonium and nitrite peaked in the Hamburg port region with up to 25 ?M and 12 ?M, respectively. In July 2013, ?15N of ammonium has shown a mean value of 16.23.3 o and nitrite of -9.84.7 The N-fractionation of nitrification in July 2013 was 15?nit -10o the sub-process ammonia oxidation 15?amox-24o and the nitrite oxidation of 15?niox 13o while fractionation was less pronounced during the other cruises Our data show that N-isotope fractionation generally confirmed culture experiments, but that it strongly depended on discharge, availability of substrate, temperature and the coupling of ammonia and nitrite oxidation.

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

    Eyo Victor Oscar

    2015-04-01

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

  14. 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

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

    1981-01-01

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

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

    Garono, Ralph; Robinson, Rob

    2003-10-01

    Developing an understanding of the distribution and changes in estuarine and riparian habitats is critical to the management of biological resources in the lower Columbia River. In a recently completed comprehensive ecosystem protection and enhancement plan for the lower Columbia River Estuary (CRE), Jerrick (1999) identified habitat loss and modification as one of the key threats to the integrity of the CRE ecosystem. This management plan called for an inventory of habitats as key first step in the CRE long-term restoration effort. While previous studies have produced useful data sets depicting habitat cover types along portions of the lower CRE (Thomas, 1980; Thomas, 1983; Graves et al., 1995; NOAA, 1997; Allen, 1999), no single study has produced a description of the habitats for the entire CRE. Moreover, the previous studies differed in data sources and methodologies making it difficult to merge data or to make temporal comparisons. Therefore, the Lower Columbia River Estuary Partnership (Estuary Partnership) initiated a habitat cover mapping project in 2000. The goal of this project was to produce a data set depicting the current habitat cover types along the lower Columbia River, from its mouth to the Bonneville Dam, a distance of {approx}230-km (Fig. 1) using both established and emerging remote sensing techniques. For this project, we acquired two types of imagery, Landsat 7 ETM+ and Compact Airborne Spectrographic Imager (CASI). Landsat and CASI imagery differ in spatial and spectral resolution: the Landsat 7 ETM+ sensor collects reflectance data in seven spectral bands with a spatial resolution of 30-m and the CASI sensor collects reflectance data in 19 bands (in our study) with a spatial resolution of 1.5-m. We classified both sets of imagery and produced a spatially linked, hierarchical habitat data set for the entire CRE and its floodplain. Landsat 7 ETM+ classification results are presented in a separate report (Garono et al., 2003). This report presents classification results from analysis of the CASI imagery. Data sets produced for this project from both types of imagery fill a critical information gap by creating a current description of the condition and extent of estuarine habitat cover types along the lower Columbia River. Results from this study will be used by the Estuary Partnership and its cooperators to: (1) develop indicators of 'habitat health' and biological integrity; (2) develop definitions of 'critical salmonid habitat'; (3) identify and evaluate potential wetland conservation and restoration sites; (4) track exotic and invasive species; and (5) develop an understanding of how estuarine and riverine habitats have changed over the past 200 years. This study focuses on estuarine and riparian habitat cover types important to native species, particularly juvenile salmonids. This study is meant to provide support to the multiple efforts currently underway to recover 12 species of Columbia River salmonids identified as endangered or threatened under the Endangered Species Act.

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

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

    2009-09-08

    The purpose of this study was to evaluate the ability to enhance distribution of eelgrass (Zostera marina) in the Columbia River Estuary to serve as refuge and feeding habitat for juvenile salmon, Dungeness crab, and other fish and wildlife. We strongly suspected that limited eelgrass seed dispersal has resulted in the present distribution of eelgrass meadows, and that there are other suitable places for eelgrass to survive and form functional meadows. Funded as part of the Bonneville Power Administration's call for Innovative Projects, we initiated a multistage study in 2008 that combined modeling, remote sensing, and field experimentation to: (1) Spatially predict habitat quality for eelgrass; (2) Conduct experimental plantings; and (3) Evaluate restoration potential. Baseline in-situ measurements and remote satellite observations were acquired for locations in the Lower Columbia River Estuary (LCRE) to determine ambient habitat conditions. These were used to create a habitat site-selection model, using data on salinity, temperature, current velocity, light availability, wave energy, and desiccation to predict the suitability of nearshore areas for eelgrass. Based on this model and observations in the field, five sites that contained no eelgrass but appeared to have suitable environmental conditions were transplanted with eelgrass in June 2008 to test the appropriateness of these sites for eelgrass growth. We returned one year after the initial planting to monitor the success rate of the transplants. During the year after transplanting, we carried out a concurrent study on crab distribution inside and outside eelgrass meadows to study crab usage of the habitat. One year after the initial transplant, two sites, one in Baker Bay and one in Young's Bay, had good survival or expansion rates with healthy eelgrass. Two sites had poor survival rates, and one site had a total loss of the transplanted eelgrass. For submerged aquatic vegetation (SAV) restoration projects, these are reasonable success results and represent a small net gain in eelgrass in the LCRE. Crabs used both the eelgrass and unvegetated substrate, though in neither were there great abundance of the young-of-the-year crabs. During the field assessment of 12 potential transplant sites, divers discovered one site in southern Young's Bay that contained a previously undocumented eelgrass bed. This integrated project developed the first predictive maps of sites suitable for eelgrass and other SAV in the lower estuary. In addition, techniques developed for this project to assess light levels in existing and potential submerged habitats have great potential to be used in other regions for nearshore and coastal monitoring of SAV. Based on these preliminary results, we conclude that eelgrass distribution could likely be expanded in the estuary, though additional information on current eelgrass locations, usage by species of interest, and monitoring of current conditions would help develop a baseline and verify benefit. Our recommendations for future studies include: (1) Site Monitoring. Continued monitoring of restoration sites along with physical metrics of light, temperature and salinity within beds. Continued monitoring will both assist managers in understanding the longevity and expansion rate of planted sites and inform practical guidance on the minimum planted eelgrass required to develop a resilient meadow. (2) Natural bed documentation and monitoring. Document current eelgrass habitat conditions in the Columbia River by mapping eelgrass and other SAV species and monitoring physical metrics in natural beds. This will assist by better defining the factors that control the annual and spatial variation in eelgrass in the estuary, and thus lead to improved management. Improved information on conditions will help refine a habitat suitability model that can more accurately predict where eelgrass can be restored or areas under duress. (3) Monitor Species Use. Expanded monitoring of Dungeness crab and salmon use and benefit from eelgrass in the estuary to evaluate how feeding and rearing functions of eelgrass benefit the survival and growth of these species. We have two final recommendations. First, if transplanting of eelgrass is to be expanded, donor stocks of plants should also be expanded to reduce the dependence on natural meadows. We recommend that an eelgrass culture facility be considered to supply stocks of eelgrass for planting that are developed from the eelgrass populations now in the estuary. Second, freshwater submerged aquatic vegetation (SAV) occurs in many parts of the estuary, and probably has importance to juvenile salmon (although this also needs verification). Restoration and expansion of freshwater SAV should be considered in a comprehensive effort to restore the submerged vegetation habitats through the Columbia River estuary.

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

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

    2014-01-01

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

  18. 78 FR 23746 - Takes of Marine Mammals Incidental to Specified Activities; Russian River Estuary Management...

    2013-04-22

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

  19. 77 FR 24471 - Takes of Marine Mammals Incidental to Specified Activities; Russian River Estuary Management...

    2012-04-24

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

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

    Sarma, V.V; 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

    or minus 7.2 mu MCl sup(-1) d sup(-1)) in the estuary resulted in very high pCO sub(2) of approx. 30,000 mu atm during peak discharge period, which otherwise were <500 mu atm during dry period. Such high pCO sub(2) levels were unknown to occur in any...

  1. 75 FR 17382 - Small Takes of Marine Mammals Incidental to Specified Activities; Russian River Estuary Water...

    2010-04-06

    ... Federal Register (74 FR 58248) for the take of marine mammals incidental to Estuary water level management... notice (74 FR 58248). In summary, harbor seals are the most abundant marine mammal found at the mouth of.... In all five years of monitoring, no stampedes were recorded; however, most seals will flush off...

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

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

    2006-05-15

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

  3. Impact of the Three Gorges Dam, the South–North Water Transfer Project and water abstractions on the duration and intensity of salt intrusions in the Yangtze River estuary

    M Webber; Li, M. T.; Chen, J.; Finlayson, B.; Chen, D; Z. Y. CHEN; M. Wang; J. Barnett

    2015-01-01

    This paper assesses the impacts of the Three Gorges Dam, the South–North Water Transfer Project and other water abstractions on the probability of long-duration salt intrusions into the Yangtze River estuary. Studies of intrusions of saltwater into estuaries are typically constrained by both the short duration of discharge records and the paucity of observations of discharge and salinity. Thus, studies of intrusions of saltwater into estuaries typically seek to identify the ...

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

    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.

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

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

    2013-01-01

    The mangrove oyster, Crassostrea rhizophorae (Bivalvia, Ostreidae) is commonly collected by fisherwomen in the estuaries of the Ceará State (CE), Northeastern Brazil. Despite the socioeconomic importance of this natural resource, there are few studies on the health of the oysters in this region. This study aimed to survey pathological changes in the mangrove oyster C. rhizophorae in the estuary of the Pacoti River, CE. Adult oysters were collected in August 2008 (N=450) and December 2009 (N=450) at three sites of the Pacoti estuary and in 2010 (N=600) samplings were done quarterly at one site which has showed the higher prevalence de Perkinsus. Macroscopical and histological analyses were used to evaluate pathological changes, Ray's Fluid Thioglycollate Medium (RFTM) to detect Perkinsus spp. and polymerase chain reactions (PCR) and DNA sequencing to identify Perkinsus species. In 2009, RFTM assay detected Perkinsus sp. infecting the tissues of C. rhizophorae with low prevalences of 1.3%, 6.7% e 7.3% in sites 1, 2 and 3, respectively, and in 2010, in site 3, prevalence was 2% (12 of 600 oysters). PCR did not confirm any positive case in 2009 and only 5 in 2010. The phylogenetic analyses strongly indicate that the Perkinsus species infecting oysters C. rhizophorae of this study belongs to Perkinsus beihaiensis. The histology confirmed 11 cases of Perkinsus sp. infecting the C. rhizophorae in 2009, and only two cases in 2010. Nematopsis sp. was the protozoan observed with greater prevalence (up 96.7%). Other found protozoa were: Trichodina, Sphenophrya, Ancistrocoma - like and an unknown ovarian parasite. The metazoa found were the polychaete Polydora with high prevalences, a turbellarian, possibly of the genus Urastoma, an unidentified digenean metacercariae and larvae of cestode Tylocephalum. A continuous monitoring of diseases in bivalves from this natural population is recommended, since the phylogenetic analyses indicate the occurrence of P. beihaiensis infecting oysters C. rhizophorae whose pathogenic potential is unknown. PMID:23147104

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

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

    1981-11-01

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

  7. Effect of Migration Pathway on Travel Time and Survival of Acoustic-Tagged Juvenile Salmonids in the Columbia River Estuary

    Harnish, Ryan A.; Johnson, Gary E.; McMichael, Geoffrey A.; Hughes, Michael S.; Ebberts, Blaine D.

    2012-02-01

    Off-channel areas (side channels, tidal flats, sand bars, and shallow-water bays) may serve as important migration corridors through estuarine environments for salmon and steelhead smolts. Relatively large percentages (21-33%) of acoustic-tagged yearling and subyearling Chinook salmon and steelhead smolts were detected migrating through off-channel areas of the Columbia River estuary in 2008. The probability of survival for off-channel migrants (0.78-0.94) was similar to or greater than the survival probability of main channel migrants (0.67-0.93). Median travel times were similar for all species or run types and migration pathways we examined, ranging from 1-2 d. The route used by smolts to migrate through the estuary may affect their vulnerability to predation. Acoustic-tagged steelhead that migrated nearest to avian predator nesting colonies experienced higher predation rates (24%) than those that migrated farthest from the colonies (10%). The use of multiple migration pathways may be advantageous to out-migrating smolts because it helps to buffer against high rates of mortality, which may occur in localized areas, and helps to minimize inter- and intraspecific competition.

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

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

    2016-03-01

    Coastal and estuarine regions are important areas of mercury pollution. Therefore, it is important to properly characterize the sources and bioaccumulation processes of mercury in these regions. Here, we present mercury stable isotopic compositions in 18 species of wild marine fish collected from the Pearl River Estuary (PRE), south China. Our results showed variations in mass-independent fractionation (?(199)Hg:+0.050.10 to+0.590.30) with a ?(199)Hg/?(201)Hg of ?1.26, suggesting that aqueous MeHg underwent photo-degradation prior to incorporation into the food chain. For the results, we discovered small but significant differences of ?(199)Hg values among herbivorous, demersal, and carnivorous fish, indicating that different feeding guilds of fish may have incorporated MeHg with various degrees of photo-demethylation. The consistent mercury isotope compositions between fish feeding habitat and mercury sources in the estuary provide potentially important findings on the transformation and bioaccumulation of this toxic metal in subtropical coastal environments. PMID:26766353

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

    Aliou Dia

    2006-04-01

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

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

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

    2013-04-01

    The stocks of Southern sea lions (Otaria flavescens, SSL) and South American fur seals (SAFS) that breed on coastal islands of Uruguay constitute the most important focal concentration of pinnipeds in South America, with a significant increase in SAFS and a steady decrease of SSL over the past decades. Because females are a key element of population dynamics and no information exists on the post-breeding pup rearing period, we studied the foraging patterns of SSL females in the La Plata River Estuary (LPRE) during mid and late lactation (late austral autumn and winter), analyzing the foraging performance, geographic coverage and ontogenetic differences in foraging strategies for a period of 1-5 months. At-sea movements of 22 SSL females (6 subadults and 16 adults) from Isla de Lobos (IL, 35°01'28"S-54°52'59"W, Uruguay) were monitored using satellite transmitters (SPOT4, SPOT5 and STDR-S16, Wildlife Computers) in 2007 and 2010. An algorithm [McConnell, B.J., Chambers, C., Fedak, M.A., 1992. Foraging ecology of southern elephant seals in relation to the bathymetry and productivity of the Southern Ocean. Antarct. Sci. 4, 393-398.] with a maximum transit speed of 3 m s-1 was applied to the Argos information, resulting in a total of 2522 filtered locations. A daily mean of 3.5±1.74 filtered locations per animal was received. One hundred and eighty three foraging trips (FT) were recorded with no significant differences (p<0.05) between subadults and adults in the duration of FT (6.1±3.15 day), distance traveled per FT (237.2±105.25 km), mean distance from IL (57.2±25.90 km), maximum straight line (Spider) distance (100.2±41.40 km) and transit speed (1.1±1.04 m s-1). SSL showed directional fidelity to foraging sites, indicated by high mean vector (r) values (0.74±0.14) calculated from FT mean bearings. Kernel ranges for 50% and 95% of all FT locations were 5420 km2 and 36,222 km2, respectively, and the extension of the foraging areas appeared to be influenced by a combination of bathymetry and ecological boundaries within LPRE. Regardless of their reproductive condition, females showed a strong fidelity to IL, and their foraging activity was restricted to relatively shallow areas (10-100 m) on the continental shelf. During autumn and winter, SSL females made significantly longer FTs than during the breeding season, when lactating females decrease FT duration by increasing transit speed but maintain a similar spatial coverage compared with FT later in lactation. Although several aquatic areas of high priority for conservation in LPRE have been identified and proposed, only 15% of the foraging habitat of SSL females is currently included in these areas. This emphasizes the importance of the inclusion of the at-sea foraging distributions of central point foragers in marine protected areas. If conservation efforts focus only on coastal breeding concentrations, key elements of the life cycle are excluded with potential unpredictable effects.

  11. 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

    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.

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

    Jos 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.

  13. Biological effects of simulated discharge plume entrainment at Indian Point Nuclear Power Station, Hudson River estuary, USA

    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 ΔT 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 ΔT produced statistically significant moralities. (author)

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

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

    2015-06-01

    The concentrations of Ca, Mg, K, Zn, Pb, Cd, Co, Cr, Cu, Fe, Ni and Na were determined in the sediment and biota of the Bonny/New Calabar River Estuary in Niger Delta, Nigeria using atomic absorption spectrophotometer A-100. The concentration of the respective metals varied between 2011 and 2012. The range of mean values are presented in mg/kg along with variations at a statistically significant level ( P<0.05). In sediment, only Cr varied significantly ( p<0.05) within the two years. Bioaccumulation factor (BF) indicated a more potent source of metals from sediment than biota, accumulating Zn, Fe and Ni in magnitudes 10, 6 and 5 times more, respectively. The study shows elevated levels of heavy metals in sediment and bioaccumulation in biota. Regular monitoring and comparison of results with World Health Organization maximum permissible limits should be carried out, in order not to allow the metal concentration to reach alarming levels.

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

    Khwanruan Srinui

    2013-10-01

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

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

    Srinui, Khwanruan; Nishida, Shuhei; Ohtsuka, Susumu

    2013-01-01

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

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

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

    2013-07-01

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

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

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

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

    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. Mller, H. baltica Simonsen, H. distinctepunctata (Hustedt Hustedt, H. elegantula (strup 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 strup 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.

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

    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

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

    Sun, Zhigao; Mou, Xiaojie; Sun, Wanlong

    2016-03-01

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

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

    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.

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

    Sharif, Abubaker; Monperrus, Mathilde; Tessier, Emmanuel; Bouchet, Sylvain; Pinaly, Hervé; Rodriguez-Gonzalez, Pablo; Maron, Philippe; Amouroux, David

    2014-10-15

    Because mercury (Hg) undergoes significant biogeochemical processes along the estuarine-coastal continuum, the objective of this work was to investigate the distribution and reactivity of methylmercury (MeHg), inorganic mercury (Hg(II)) and gaseous Hg (DGM) in plume waters of the Adour River estuary (Bay of Biscay). Vertical profiles, spatial and tidal variability of Hg species concentrations were evaluated during two campaigns (April 2007 and May 2010) characterized by significant plume extents over the coastal zone. Incubations with isotopically enriched tracers were performed on bulk and filtered waters under sunlight or dark conditions to investigate processes involved in Hg methylation, demethylation and reduction rates. Total Hg(II) concentrations were more dispersed in April 2007 (5.2 ± 4.9 pM) than in May 2010 (2.5 ± 1.1 pM) while total MeHg concentrations were similar for both seasons and averaged 0.13 ± 0.07 and 0.18 ± 0.11 pM, respectively. DGM concentrations were also similar between the two campaigns, averaging 0.26 ± 0.10 and 0.20 ± 0.09 pM, respectively. Methylation yields remained low within the estuarine plume (dark conditions. The results suggest that the plume is overall a sink for MeHg with integrated net demethylation rates, ranging from 2.0-3.7 g (Hg) d(-1), in the same range than the estimated MeHg inputs from the estuary (respectively, 0.9 and 3.5 g (Hg) d(-1)). The large evasion of DGM from the plume waters to the atmosphere (8.8-26.9 g (Hg) d(-1)) may also limit HgT inputs to coastal waters (33-69 g (Hg) d(-1)). These processes are thus considered to be most significant in controlling the fate of Hg transferred from the river to the coastal zone. PMID:25091142

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

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

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

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

    2016-01-15

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

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

    Zhang, Shiyan; Mao, Xian-zhong

    2015-10-01

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

  7. Effects of runoff changes and sea level rise on salinity in the Delaware River estuary

    Walters, Roy A.

    1989-01-01

    The objective of this study is to investigate changes in the spatial distribution of salt in the Delaware Estuary resulting from climate induced changes in freshwater inflows and in the position of mean sea level. The approach adopted for this study is composed of two parts: An analysis of existing physical data in order to derive a basic understanding of the salt dynamics, and numerical simulation of future conditions based upon this analysis.

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

    Because mercury (Hg) undergoes significant biogeochemical processes along the estuarine-coastal continuum, the objective of this work was to investigate the distribution and reactivity of methylmercury (MeHg), inorganic mercury (Hg(II)) and gaseous Hg (DGM) in plume waters of the Adour River estuary (Bay of Biscay). Vertical profiles, spatial and tidal variability of Hg species concentrations were evaluated during two campaigns (April 2007 and May 2010) characterized by significant plume extents over the coastal zone. Incubations with isotopically enriched tracers were performed on bulk and filtered waters under sunlight or dark conditions to investigate processes involved in Hg methylation, demethylation and reduction rates. Total Hg(II) concentrations were more dispersed in April 2007 (5.2 ± 4.9 pM) than in May 2010 (2.5 ± 1.1 pM) while total MeHg concentrations were similar for both seasons and averaged 0.13 ± 0.07 and 0.18 ± 0.11 pM, respectively. DGM concentrations were also similar between the two campaigns, averaging 0.26 ± 0.10 and 0.20 ± 0.09 pM, respectively. Methylation yields remained low within the estuarine plume (< 0.01–0.4% day−1) while MeHg was efficiently demethylated via both biotic and abiotic pathways (2.3–55.3% day−1), mainly photo-induced. Hg reduction was also effective in these waters (0.3–43.5% day−1) and was occurring in both light and dark conditions. The results suggest that the plume is overall a sink for MeHg with integrated net demethylation rates, ranging from 2.0–3.7 g (Hg) d−1, in the same range than the estimated MeHg inputs from the estuary (respectively, 0.9 and 3.5 g (Hg) d−1). The large evasion of DGM from the plume waters to the atmosphere (8.8–26.9 g (Hg) d−1) may also limit HgT inputs to coastal waters (33–69 g (Hg) d−1). These processes are thus considered to be most significant in controlling the fate of Hg transferred from the river to the coastal zone. - Highlights: • Reactivity of mercury species was investigated in plume waters of the Adour Estuary. • In situ water incubations were performed to examine transformation processes of Hg. • A net MeHg demethylation was observed via both light induced and biotic pathways. • The estuarine plume exhibits significant loss of MeHg and atmospheric evasion of Hg

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

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

    2014-08-01

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

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

    DileepKumar, M.

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

  11. Zinc toxicity in the fish Cnesterodon decemmaculatus in the Paraná River and Río de La Plata Estuary.

    Gómez, S; Villar, C; Bonetto, C

    1998-01-01

    Acute static tests were performed to assess Zn toxicity on adults of Cnesterodon decemmaculatus (not sexed), a neotropical fish of wide distribution in the Río de la Plata basin. Tests were carried out with ZnCl2 dissolved in natural waters from the Lower Paraná River, the Río de la Plata Estuary, reconstituted waters of similar composition, tap and distilled waters. Median lethal concentration at 24 h was positively correlated to conductivity and the concentrations of Ca2+, Mg2+, and HCO3- (r=0.99, 0.96, 0.97, 0.99, pPlata Estuary (61.2 mg l(-1)) than at the Lower Paraná River (35.3 mg l(-1)). Contaminant load in the natural waters tested was similar at both sites, being Zn concentration 40 and 44 microg l(-1), respectively. An assay with reconstituted water of similar alkalinity to the estuary showed a simultaneous decrease in HCO3- and dissolved Zn, while the Zn speciation, predicted with a computer program, suggested that Zn2+ precipitated as ZnCO3. The effect of Ca2+ on Zn toxicity is also discussed. Zn toxicity was higher in the Río de la Plata Estuary water than in synthetic water of similar ionic composition (24-h LC50 = 93.2 mg l(-1)), suggesting the synergistic effect of other toxic pollutants such as metals, present in the former which were absent in the later. PMID:15093310

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

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

    2011-10-01

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

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

    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

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

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

    2011-04-01

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

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

    NONE

    1994-12-31

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

  16. Surface water characteristics and trace metals level of the Bonny/New Calabar River Estuary, Niger Delta, Nigeria

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

    2015-07-01

    Surface water samples from three stations in the Bonny/New Calabar River Estuary were analyzed for the physicochemical characteristics and trace metal level in 2011 and 2012, respectively. Results show pH ranged from 7.56 to 7.88 mg/L; conductivity, 33,489.00 to 33,592.00 µScm-1; salinity, 15.33 to 15.50 ‰; turbidity, 4.35 to 6.65 NTU; total dissolved solids, 22111.00 to 23263.00 gm-3; dissolved oxygen, 4.53 to 6.65 mg/L; and biochemical oxygen demand, 1.72 mg/L. The level of some trace metals (Ca, Mg, K, Zn, Pb, Cd, Co, Cr, Cu, Fe, Ni, and Na) were also analyzed by Atomic absorption spectrometry with K, Zn, and Co being statistically significant (P BOD, temperature, and salinity during the dry season than wet season. Concentrations of trace metals such as Pb, Cd, Zn, Ni, and Cr were higher than stipulated limits by WHO (2006). The result of the Metal Pollution Index suggests that the river was slightly affected and therefore continuous monitoring is necessary to avert possible public health implications of these metals on consumers of water and seafood from the study area.

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

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

    2015-08-01

    We investigated spatial and temporal changes in the quality of sedimentary organic matter and trophic status of the Cochin estuarine system, southwest coast of India. Sediment samples were collected in five sampling campaigns from January 2009 to April 2010. TOC/N ratio implied mixed input of autochthonous as well as remarkable allochthonous terrestrial higher plant debris into the sedimentary system. More depleted 13C values at riverine and industrial zone suggested a major contribution of terrestrial higher plant debris to sedimentary organic matter. Trophic status of the estuary changed seasonally to eutrophic via oligotrophic and mesotrophic conditions during the period January 2009 to April 2010. The protein to carbohydrate ratio was lower (<1), indicating heterotrophic nature and the higher lipid to carbohydrate ratio (>1) denoted preservation of lipid compounds in the sediments. Correlation analyses provide evidence of the association of chlorophyll pigments with carbohydrates and account for the highly productive nature of the estuary and algal contributions to organic matter. Canonical correspondence analysis clearly illustrated prominence of phaeopigments in fishing zone, lipids in sewage/tourism influenced zone, carbohydrates in riverine zone and proteins in industrial zone. It also indicated the influence of sedimentary texture, pH and organic carbon to the distribution of biochemical constituents.

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

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

    2015-08-01

    We investigated spatial and temporal changes in the quality of sedimentary organic matter and trophic status of the Cochin estuarine system, southwest coast of India. Sediment samples were collected in five sampling campaigns from January 2009 to April 2010. TOC/N ratio implied mixed input of autochthonous as well as remarkable allochthonous terrestrial higher plant debris into the sedimentary system. More depleted δ 13C values at riverine and industrial zone suggested a major contribution of terrestrial higher plant debris to sedimentary organic matter. Trophic status of the estuary changed seasonally to eutrophic via oligotrophic and mesotrophic conditions during the period January 2009 to April 2010. The protein to carbohydrate ratio was lower (1) denoted preservation of lipid compounds in the sediments. Correlation analyses provide evidence of the association of chlorophyll pigments with carbohydrates and account for the highly productive nature of the estuary and algal contributions to organic matter. Canonical correspondence analysis clearly illustrated prominence of phaeopigments in fishing zone, lipids in sewage/tourism influenced zone, carbohydrates in riverine zone and proteins in industrial zone. It also indicated the influence of sedimentary texture, pH and organic carbon to the distribution of biochemical constituents.

  19. Identification of heavy metal sources in the reclaimed farmland soils of the pearl river estuary in China using a multivariate geostatistical approach.

    Gu, Yang Guang; Li, Qu Sheng; Fang, Jian Hong; He, Bao Yan; Fu, Hong Bo; Tong, Ze Jun

    2014-07-01

    Heavy metals in the reclaimed farmland soils of the Pearl River Estuary in China have attracted much attention because of the health risk posed to local residents. The identification of heavy metal sources in these soils is necessary to reduce their health risk. Reclaimed farmland soil samples were collected from 144 sites in the Pearl River Estuary and the contents of heavy metals (Cd, Pb, Cr, Ni, Cu, and Zn) were determined. All these heavy metals showed concentrations substantially higher than their background values, indicating possible anthropogenic pollution. The results of a multivariate geostatistical method demonstrate that grouped Cd, Cr, and Cu were mainly controlled by chemical fertilizers. Grouped Pb and Zn were the most severely impacted by atmospheric deposition from Guangzhou and Foshan, and Ni was primarily impacted by electroplating factories' wastewater discharge. PMID:24780227

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

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

    2006-01-01

    Bacterioplankton abundance, biomass and growth rates were studied in the Minho Estuary River (NW Portugal). The influence of tidal conditions, glucose amendment, and the filtration process on total bacterial abundance, total and faecal coliforms, as well as faecal streptococci, were evaluated in ...... were induced at high tide that led to a lack of bacterial growth and the net disappearance of most of the bacterial populations. Glucose amendment, at used concentration, was not found to stimulate bacterial growth, which instead could be limited by inorganic nutrients.......Bacterioplankton abundance, biomass and growth rates were studied in the Minho Estuary River (NW Portugal). The influence of tidal conditions, glucose amendment, and the filtration process on total bacterial abundance, total and faecal coliforms, as well as faecal streptococci, were evaluated in...

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

    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.

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

    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 HPLCMS/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

  3. Genetic and biogeochemical investigation of sedimentary nitrogen cycling communities responding to tidal and seasonal dynamics in Cape Fear River Estuary

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

    2015-12-01

    Tidal and seasonal fluctuations in the oligohaline reaches of estuaries may alter geochemical features that influence structure and function of microbial communities involved in sedimentary nitrogen (N) cycling. In order to evaluate sediment community responses to short-term (tidal) and long-term (seasonal) changes in different tidal regimes, nitrogen cycling rates and genes were quantified in three sites that span a range of tidal influence in the upper portion of the Cape Fear River Estuary. Environmental parameters were monitored during low and high tides in winter and spring. 15N tracer incubation experiments were conducted to measure nitrification, denitrification, anaerobic ammonium oxidation (anammox), and dissimilatory nitrate reduction to ammonia (DNRA). Abundances of functional genes including bacterial and archaeal ammonia monooxygenase (amoA), nitrite reductases (nirS and nrfA), nitrous oxide reductase (nosZ), and hydrazine oxidoreductase (hzo) were measured using quantitative PCR assays. Denitrification rates were highest among the measured N cycling processes while bacteria carrying nrfA genes were most abundant. A discernable pattern in the short-term variation of N cycling rates and gene abundance was not apparent under the different tidal regimes. Significant seasonal variation in nitrification, denitrification, and anammox rates as well as bacterial amoA, nirS and nosZ gene abundance was observed, largely explained by increases in substrate availability during winter, with sediment ammonium playing a central role. These results suggest that the coupling of nitrification to N removal pathways is primarily driven by organic carbon mineralization and independent of tidal or salinity changes. Finally, changes in denitrification and nitrification activities were strongly reflected by the abundance of the respective functional genes, supporting a linkage between the structure and function of microbial communities.

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

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

    2013-02-15

    Concentrations, distributions, fate, and partitioning of perfluoroalkyl acids (PFAAs) were investigated in surface water (n=34) collected from the Youngsan and Nakdong River Estuaries of South Korea. Thirteen individual PFAAs in water and suspended solids (SS) were quantified by use of HPLC-MS/MS. PFAAs were detected in all samples, which indicated that they were widely distributed in the study area. Greater concentrations of PFAAs were found at some inland sites which seemed to be affected by direct input from point sources, such as wastewater treatment plants, and/or indirect diffusive sources, such as surface runoff. Spatial distributions of PFAAs in estuaries along transects toward the open sea demonstrated that these chemicals were transported to the outer region primarily by water discharged during the rainy season. Field-based partition coefficients (K(d)) for long-chain PFAAs (C?8) were significantly correlated with salinity (r(2)=0.48 to 0.73, p<0.01); K(d) values increased exponentially as a function of salinity. Due to the 'salting-out' effect, PFAAs were largely scavenged by adsorption onto SS and/or sediments in estuarine environments. In addition, values for K(d) of those PFAAs were directly proportional to the number of carbon atoms in the PFAAs. Salting constants of selected PFAAs were notably greater than those of other environmental organic contaminants, which indicated that adsorption of PFAAs is largely associated with salinity. Overall, the results of the present study will provide better understanding of the fate and transport of PFAAs in the zone of salinity boundary that can be used for developing fate models of PFAAs in the coastal marine environment. PMID:23333509

  5. 234Th and 7Be as tracers for transport and sources of particle-associated contaminants in the Hudson River Estuary.

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

    1999-09-30

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

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

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

    2011-01-01

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

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

    Kleber Grubel da Silva; Danielle Paludo; Eunice Maria Almeida de Oliveira; Régis Pinto de Lima; Ricardo José Soavinski

    2011-01-01

    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 ...

  8. Drought and flood effects on macrobenthic communities in the estuary of Australia's largest river system

    Dittmann, Sabine; Baring, Ryan; Baggalley, Stephanie; Cantin, Agnes; Earl, Jason; Gannon, Ruan; Keuning, Justine; Mayo, Angela; Navong, Nathavong; Nelson, Matt; Noble, Warwick; Ramsdale, Tanith

    2015-11-01

    Estuaries are prone to drought and flood events, which can vary in frequency and intensity depending on water management and climate change. We investigated effects of two different drought and flow situations, including a four year long drought (referred to as Millennium drought) and a major flood event, on the macrobenthic community in the estuary and coastal lagoon of the Murray Mouth and Coorong, where freshwater inflows are strictly regulated. The analysis is based on ten years of annual monitoring of benthic communities and environmental conditions in sediment and water. The objectives were to identify changes in diversity, abundance, biomass and distribution, as well as community shifts and environmental drivers for the respective responses. The Millennium drought led to decreased taxonomic richness, abundance and biomass of macrobenthos as hypersaline conditions developed and water levels dropped. More taxa were found under very high salinities than predicted from the Remane diagram. When a flood event broke the Millennium drought, recovery took longer than from a shorter drought followed by small flows. A flow index was developed to assess the biological response subject to the duration of the preceding drought and flow volumes. The index showed higher taxonomic richness, abundance and biomass at intermediate and more continuous flow conditions. Abundance increased quickly after flows were restored, but the benthic community was initially composed of small bodied organisms and biomass increased only after several years once larger organisms became more abundant. Individual densities and constancy of distribution dropped during the drought for almost all macrobenthic taxa, but recoveries after the flood were taxon specific. Distinct benthic communities were detected over time before and after the drought and flood events, and spatially, as the benthic community in the hypersaline Coorong was split off with a salinity threshold of 64 identified by LINKTREE analysis. Salinity, low dissolved oxygen saturation and sediment properties accounted for further community splits in the estuarine Murray Mouth. This long term monitoring revealed ecological benefits of intermediate and continuous flow and that resilience of estuarine macrobenthos to drought and flood events was affected by flow history. The index can be applied to other flow regulated estuaries and inform environmental watering targets.

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

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

    2010-06-01

    Full Text Available A situao socioeconmica de Bragana depende principalmente dos recursos biolgicos estuarinos e marinhos, que so influenciados pelos ciclos de mars e climatologia. Coletas oceanogrficas (com medidas de variveis hidrolgicas, hidro-dinmicas e microbiolgicas) foram realizadas na rea mais urba [...] nizada do esturio do Caet, para caracterizar a qualidade das guas no setor estudado. Durante o perodo seco, o esturio foi mais eutrfico e apresentou os maiores valores de temperatura (30,5C 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 espcies fitoplanct-nicas Cyclotella meneghiniana, Coscinodiscus centralis e outras espcies r-estrategistas tambm foram observadas. A falta de saneamento bsico foi responsvel pela contaminao local, especialmente durante o perodo seco, quando o esgoto foi lanado mais concentrado no esturio, mostrando a influncia humana na reduo da qualidade da gua estuarina estudada. A pesca considerada uma das principais atividades econmicas do municpio de Bragana e, portanto, esta contaminao poder afetar negativamente a qualidade ambiental deste ecossistema amaznico. Abstract in english Bragana'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 Caet 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 Bragana, the fishery is considered one of the main economic activities so, this contamination is worrisome because a large part of the local economy depends on biological resources and, thus, the contamination could negatively affect the environmental health of this Amazon ecosystem.

  10. Long-term monitoring of metal pollution in sediments from the estuary of the Nerbioi-Ibaizabal River (2005-2010)

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

    2013-10-01

    This work aims to investigate the spatial and temporal distribution of trace metals in sediment samples taken from the Nerbioi-Ibaizabal River estuary (Bilbao, Basque Country) over the course of a long-term surveillance monitoring programme from 2005 to 2010. Sediment Quality Guidelines (SQGs) and the geoaccumulation indexes (Igeo) were used to assess the environmental risk posed by metal content in the estuary sediment. Sediment was collected at eight different sites in the estuary every three months over the period of investigation. A total of 14 elements (Al, As, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Sn, V and Zn) were selected and the concentration of each was measured in all samples. Additionally, conductivity, pH and the concentration of carbonate, total organic carbon and fulvic and humic acids were also measured in those samples collected in sampling campaigns from March 2006 to October 2008. The concentration of most of the metals systematically decreased over the period of investigation. There are still some points of the estuary (those located in the surroundings of the Gobela and Galindo tributaries), however, where concentrations of As, Cd, Cu, Pb and Zn are significantly higher than the background values estimated for the area. According to the mean Effects Range Median quotients (mERMqs) calculated for these sites, sediments may still pose a toxicological threat to living organisms. Metal content in inner estuary sediment is low. Specific point sources of metals to the estuary, together with background contamination of diffuse origin, are probably responsible for this situation.

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

    Deconinck, Nico

    2011-01-01

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

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

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

    2012-04-01

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

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

    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 19July 16) from Station Lijin (a hydrologic station nearest to the Yellow River estuary). The monthly samples showed dissolved uranium concentrations of 3.857.57 ?g l?1 and 234U/238U activity ratios of 1.241.53. 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

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

    Sharif, Abubaker; Monperrus, Mathilde; Tessier, Emmanuel; Bouchet, Sylvain; Pinaly, Hervé; Rodriguez-Gonzalez, Pablo [Laboratoire de Chimie Analytique Bio-Inorganique et Environnement, Institut Pluridisciplinaire de Recherche sur l' Environnement et les Matériaux, UMR 5254 CNRS, Université de Pau et des Pays de l' Adour, Hélioparc Pau Pyrénées, 2 av. P. Angot, 64053 Pau cedex 9 (France); Maron, Philippe [Laboratoire des Sciences de l' Ingénieur Appliquées à la Mécanique et au Génie Electrique, Institut Supérieur Aquitain du Bâtiment et des Travaux Publics, Université de Pau et des Pays de l' Adour, Allée du Parc Montaury, 64600 Anglet (France); Amouroux, David, E-mail: david.amouroux@univ-pau.fr [Laboratoire de Chimie Analytique Bio-Inorganique et Environnement, Institut Pluridisciplinaire de Recherche sur l' Environnement et les Matériaux, UMR 5254 CNRS, Université de Pau et des Pays de l' Adour, Hélioparc Pau Pyrénées, 2 av. P. Angot, 64053 Pau cedex 9 (France)

    2014-10-15

    Because mercury (Hg) undergoes significant biogeochemical processes along the estuarine-coastal continuum, the objective of this work was to investigate the distribution and reactivity of methylmercury (MeHg), inorganic mercury (Hg(II)) and gaseous Hg (DGM) in plume waters of the Adour River estuary (Bay of Biscay). Vertical profiles, spatial and tidal variability of Hg species concentrations were evaluated during two campaigns (April 2007 and May 2010) characterized by significant plume extents over the coastal zone. Incubations with isotopically enriched tracers were performed on bulk and filtered waters under sunlight or dark conditions to investigate processes involved in Hg methylation, demethylation and reduction rates. Total Hg(II) concentrations were more dispersed in April 2007 (5.2 ± 4.9 pM) than in May 2010 (2.5 ± 1.1 pM) while total MeHg concentrations were similar for both seasons and averaged 0.13 ± 0.07 and 0.18 ± 0.11 pM, respectively. DGM concentrations were also similar between the two campaigns, averaging 0.26 ± 0.10 and 0.20 ± 0.09 pM, respectively. Methylation yields remained low within the estuarine plume (< 0.01–0.4% day{sup −1}) while MeHg was efficiently demethylated via both biotic and abiotic pathways (2.3–55.3% day{sup −1}), mainly photo-induced. Hg reduction was also effective in these waters (0.3–43.5% day{sup −1}) and was occurring in both light and dark conditions. The results suggest that the plume is overall a sink for MeHg with integrated net demethylation rates, ranging from 2.0–3.7 g (Hg) d{sup −1}, in the same range than the estimated MeHg inputs from the estuary (respectively, 0.9 and 3.5 g (Hg) d{sup −1}). The large evasion of DGM from the plume waters to the atmosphere (8.8–26.9 g (Hg) d{sup −1}) may also limit Hg{sub T} inputs to coastal waters (33–69 g (Hg) d{sup −1}). These processes are thus considered to be most significant in controlling the fate of Hg transferred from the river to the coastal zone. - Highlights: • Reactivity of mercury species was investigated in plume waters of the Adour Estuary. • In situ water incubations were performed to examine transformation processes of Hg. • A net MeHg demethylation was observed via both light induced and biotic pathways. • The estuarine plume exhibits significant loss of MeHg and atmospheric evasion of Hg.

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

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

  16. 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

    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.

  17. Numerical modelling of the geologically reconstructed Oer-IJ estuary.

    Bodewes, B.

    2015-01-01

    The Oer-IJ estuary near Castricum was active between 2500 BC and 200 BC. Geologic reconstruction resulted in paleographical maps and in hypotheses explaining its development and closure. The shape of the estuary was convergent, but with an uncharacteristic bend over the entire estuary that was perhaps caused by the washover-type initiation of the estuary. Reconstruction suggests that in the lower estuary bars were present. The estuary was connected with the Hollandse Vecht river and the Almer...

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

    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.

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

    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.

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

    Highlights: • Biogenic elements cycling in the YRE and adjacent sea surface sediments was discussed. • Factors influencing the biogenic elements distributions were examined. • Potential bioavailability of N and P was determined. • Burial fluxes of TOC, BSi, TN and TP were estimated. • Potential nutrient limitation factors were assessed. - Abstract: This study investigated the distribution and roles of total organic carbon (TOC), biogenic silicon (BSi), various forms of nitrogen (N) and phosphorus (P), and the stable carbon isotope (δ13C) in surface sediments of the Yangtze River Estuary (YRE) and adjacent sea. Terrestrial input accounted for 12–63% of total organic matter in the study area. The distribution of biogenic elements was affected by the Changjiang Diluted Water, the Jiangsu Coastal Current, human activities, marine biological processes, and the sediment grain size. Potentially bioavailable N and P accounted for an average 79.6% of the total N (TN) and 31.8% of the total P (TP), respectively. The burial fluxes for TOC, BSi, TN and TP were 39.74–2194.32, 17.34–517.48, 5.02–188.85 and 3.10–62.72 μmol cm−2 yr−1, respectively. The molar ratios of total N/P (1.2–5.0), Si/P (5.0–14.8) and Fe/P (21–61) indicated that much of the P was sequestered in sediments

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

    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

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

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

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

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

    2014-05-01

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

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

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

    2015-10-15

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

  5. Proceedings of the Columbia River Estuary Conference on Ecosystem Restoration, April 29-30, 2008, Astoria, Oregon.

    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.

  6. Metabolic and phylogenetic profile of bacterial community in Guishan coastal water (Pearl River Estuary), South China Sea

    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 γ- and α-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.

  7. [Abundance distribution of virioplankton in Yangtze River estuary and its adjacent East China Sea in summer and winter].

    Liu, Jing-jing; Zeng, Jiang-ning; Du, Ping; Chen, Quan-zhen

    2011-03-01

    An investigation was made on the abundance distribution and its variation of virioplankton in the Yangtze River estuary and its adjacent East China Sea in summer 2006 and winter 2007. The virus direct count (VDC) was quantified by fluorescent microscopy. In summer 2006, the VDC was from 2.22 x 10(6) to 9.97 x 10(7) ind x m(-1), being higher in the surface sea water of B area (122.5 degrees-123.5 degrees E); in winter 2007, the VDC was from 1.99 x 10(6) to 2.66 x 10(7) ind x mh(-1), being higher in coastal A area (120.5 degrees-122.5 degrees E) and decreased from nearshore waters to offshore waters. In summer, the VDC had close relationships with bacteriaplankton biomass and chlorophylla concentration but less relationship with nutrients concentration (P > 0.05); in winter, the VDC was closely related to bacteriaplankton biomass and nutrients concentration but less related to chlorophyll-a concentration (P > 0.05). The abundance distribution pattern of virioplankton showed significant seasonal variability, with the VDC significantly larger in summer than in winter (P < 0.01), which was mainly decided by the distribution of the viral host, and partly by the nutrients concentration in wintertime. PMID:21657040

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

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

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

    Xu, Yonghang, E-mail: yonghang_xu@163.com [Open Laboratory of Ocean and Coast Environmental Geology, Third Institute of Oceanography State Oceanic Administration, 178 Daxue Road, Xiamen 361005 (China); Sun, Qinqin [Fujian Provincial Key Laboratory of Coast and Island Management Technology Study, Fujian Institute of Oceanography, Xiamen 361013 (China); Yi, Liang [State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029 (China); Yin, Xijie; Wang, Aijun; Li, Yunhai; Chen, Jian [Open Laboratory of Ocean and Coast Environmental Geology, Third Institute of Oceanography State Oceanic Administration, 178 Daxue Road, Xiamen 361005 (China)

    2014-09-15

    Two sedimentary cores in the Minjiang River estuary (SE China) are documented for grain size, clay minerals, heavy metals, magnetic parameters and Pb isotopes to investigate the source and historical variation of heavy metals. The MJK9 core was collected outside of the Minjiang River estuary, and the core is composed of mixed sediments, of which ∼ 70% from the Yangtze River and 30% from the Minjiang River. It is thus difficult to be used for tracing the human activity along the Minjiang River. In contrast, the sediments of MJK16 core which was collected in a nearshore area are primarily from the Minjiang River. The enrichment factors of the sediments were < 1.5, indicating minor pollution. The results indicate that the sediments of the MJK16 core have Cu and Pb concentrations increasing since 1980, associated with the increase of magnetic mineral concentration and {sup 206}Pb/{sup 207}Pb and {sup 206}Pb/{sup 208}Pb of the sediments. We compared the Pb isotopic compositions between our results and those for the deposit mining in the Minjiang River basin, and aerosols and coal dust in south China, and considered that Pb in the sediments of the MJK16 core was derived primarily from weathered rocks as well as industrial emission (e.g. coal combustion). The sediments have anthropogenic Pb concentrations ranging from 6% in 1950 to 23.7% in 2010, consistent with the impact of rapid urban and industrial development in China. - Highlights: • Grain size, clay mineral and Pb isotope were used to identify sediment sources. • The contribution of Yangtze River to northern of Taiwan Strait was quantified. • Enrichment factors indicated Cu and Pb have increased over the last decades. • Coal combustion was the prevailing contamination source. • The anthropogenic Pb concentrations ranged from 6% in 1950 to 23.7% in 2010.

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

    Two sedimentary cores in the Minjiang River estuary (SE China) are documented for grain size, clay minerals, heavy metals, magnetic parameters and Pb isotopes to investigate the source and historical variation of heavy metals. The MJK9 core was collected outside of the Minjiang River estuary, and the core is composed of mixed sediments, of which ∼ 70% from the Yangtze River and 30% from the Minjiang River. It is thus difficult to be used for tracing the human activity along the Minjiang River. In contrast, the sediments of MJK16 core which was collected in a nearshore area are primarily from the Minjiang River. The enrichment factors of the sediments were < 1.5, indicating minor pollution. The results indicate that the sediments of the MJK16 core have Cu and Pb concentrations increasing since 1980, associated with the increase of magnetic mineral concentration and 206Pb/207Pb and 206Pb/208Pb of the sediments. We compared the Pb isotopic compositions between our results and those for the deposit mining in the Minjiang River basin, and aerosols and coal dust in south China, and considered that Pb in the sediments of the MJK16 core was derived primarily from weathered rocks as well as industrial emission (e.g. coal combustion). The sediments have anthropogenic Pb concentrations ranging from 6% in 1950 to 23.7% in 2010, consistent with the impact of rapid urban and industrial development in China. - Highlights: • Grain size, clay mineral and Pb isotope were used to identify sediment sources. • The contribution of Yangtze River to northern of Taiwan Strait was quantified. • Enrichment factors indicated Cu and Pb have increased over the last decades. • Coal combustion was the prevailing contamination source. • The anthropogenic Pb concentrations ranged from 6% in 1950 to 23.7% in 2010

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

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

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

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

    2014-06-15

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

  13. Sediment Storage and Heavy Metal Inventories in the Lower Reaches of the Hudson River Estuary

    Kenna, T. C.; Nitsche, F. O.; Baumgarten, J.; Haberman, M.

    2008-12-01

    Estuaries are important resources and many throughout the world are intensively used and modified by anthropogenic activities, which has resulted in instances of significant environmental contamination (e.g., heavy metals and organic contaminants). Many of these contaminants exhibit a high affinity for fine-grained sediments, making a detailed knowledge of the distribution and contaminant loading crucial to effective estuarine management. We use a hand-held X-ray fluorescence spectrometer to rapidly generate lead and other elemental distribution profiles. This technique, performed on split wet sediment cores, allows information to be collected for a significantly greater number of sediment cores than current techniques allow. When this information is combined with bulk density information that is routinely measured on sediment cores inventories of metals such as Pb, Zn, and Cu derived from anthropogenic activities (i.e., contaminant inventories) can be computed and mapped. Further, the particle reactive nature of the elements measured allows there application as proxies for other particle reactive contaminants with similar release histories. Using the penetration depth of anthropogenic contaminants in conjunction with high resolution acoustic data allows the volume of recently deposited sediments (i.e., sediments impacted by 20th century industrial activities) to be obtained. Presented results will include detailed metal inventory maps (e.g., lead, zinc, and copper) and sediment storage volume estimates from the Hudson Highlands south to the Tappan Zee area.

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

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

    2001-07-01

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

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

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

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

    Elaine Bernini

    2010-03-01

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

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

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

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

    Liu, Ying; Wang, Kui; Chen, Jianfang

    2015-04-01

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

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

    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.

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

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

    2014-02-01

    The Water-Sediment Regulation Scheme (WSRS) of the Yellow River is a procedure implemented annually from June to July to expel sediments deposited in Xiaolangdi and other large middle-reach reservoirs and to scour the lower reaches of the river, by controlling water and sediment discharges. Dissolved uranium isotopes were measured in river waters collected monthly as well as daily during the 2010 WSRS (June 19-July 16) from Station Lijin (a hydrologic station nearest to the Yellow River estuary). The monthly samples showed dissolved uranium concentrations of 3.85-7.57?gl(-1) and (234)U/(238)U activity ratios of 1.24-1.53. The concentrations were much higher than those reported for other global major rivers, and showed seasonal variability. Laboratory simulation experiments showed significant uranium release from bottom and suspended sediment. The uranium concentrations and activity ratios differed during the two stages of the WSRS, which may reflect desorption/dissolution of uranium from suspended river sediments of different origins. An annual flux of dissolved uranium of 1.04נ10(8)gy(-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 (2.65נ10(7)g) transported from the Yellow River to the sea during the WSRS constituted about 1/4 of the annual flux. PMID:24292394

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

    Bernd R. T. Simoneit; DANIEL R. OROS; Bassey O. Ekpo; Oyo-Ita, Orok E.

    2010-01-01

    The identification of 5β-stanones and their 5α-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 5β-stigmastan-3-one as maximum, and at the upper estuary a minimum value for 5α-cholestan-3-one. The elevated levels of 5β-stanones in s...

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

    Rita de Cássia Conti; Rosebel Cunha Nalesso

    2010-01-01

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

  3. Anthropogenic effects on greenhouse gas (CH{sub 4} and N{sub 2}O) emissions in the Guadalete River Estuary (SW Spain)

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

    2015-01-15

    Coastal areas are subject to a great anthropogenic pressure because more than half of the world's population lives in its vicinity causing organic matter inputs, which intensifies greenhouse gas emissions into the atmosphere. Dissolved concentrations of CH{sub 4} and N{sub 2}O have been measured seasonally during 2013 in the Guadalete River Estuary, which flows into the Cadiz Bay (southwestern Spanish coast). It has been intensely contaminated since 1970. Currently it receives wastewater effluents from cities and direct discharges from nearby agriculture crop. Eight sampling stations have been established along 18 km of the estuary. CH{sub 4} and N{sub 2}O were measured using a gas chromatograph connected to an equilibration system. Additional parameters such as organic matter, dissolved oxygen, nutrients and chlorophyll were determinate as well, in order to understand the relationship between physicochemical and biological processes. Gas concentrations increased from the River mouth toward the inner part, closer to the wastewater treatment plant discharge. Values varied widely within 21.8 and 3483.4 nM for CH{sub 4} and between 9.7 and 147.6 nM for N{sub 2}O. Greenhouse gas seasonal variations were large influenced by the precipitation regime, masking the temperature influence. The Guadatete Estuary acted as a greenhouse gas source along the year, with mean fluxes of 495.7 μmol m{sup −2} d{sup −1} and 92.8 μmol m{sup −2} d{sup −1} for CH{sub 4} and N{sub 2}O, respectively. - Highlights: • The estuary acts as a source of atmospheric methane and nitrous oxide. • Anthropogenic inputs affect the distribution of the greenhouse gases. • Dissolved gases presented an important longitudinal gradient. • Seasonal variations highly depended on the precipitation regimen.

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

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

  5. Factors affecting bacterial biomass and growth in the Duplin River estuary and coastal Atlantic Ocean.

    Fallon, R; Newell, S; Sherr, B; Sheer, E

    1984-01-01

    Bacterial numbers and growth rates were measured in coastal, planktonic systems of the Western Atlantic ocean. Seasonal responses in growth rates of the bacterial assemblage were present at some sites, but these may be related to seasonal changes in substrate supply rather than to changes in temperature. Bacterial growth rates tended to decline with increasing distance from shore. There was evidence for predator-prey population cycles in the bacteria and < 17 mu m protozoa in the Duplin River...

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

    Cbron, Aurlie; Berthe, Thierry; Garnier, Josette

    2003-01-01

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

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

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

    2009-06-03

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

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

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

    2012-02-01

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

  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

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

    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

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

    Alberto Kioharu Nishida

    1995-01-01

    Full Text Available A survey of Mytellaguyanensis occurrence and population dynamics were performed in the Paraba 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 Paraba do Norte river estuary, from the mouth to 24 km upriver. Average annual density of this bivalve species was 5.2 individuals per m, 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 ocorrncia de M, guyanensis no esturio do Rio Paraba do Norte foi mapeada, determinando-se sua presena ao longo dos afluentes e ilhas a existentes. O estudo da dinmica da populao foi realizado em rea protegida da Ilha da Restinga, coletando-se os animais ao longo de 37 transeces. A cada ms foram feitos 60 lanamentos com um delimitador de 0,1 m, sobre uma ou mais transeces. Todo o substrato foi retirado juntamente com os exemplares de M. guyanensis e a fauna associada, at a profundidade de 10 cm. A triagem dos exemplares menores foi feita por peneiramento do substrato. O tipo de substrato foi anotado a cada lanamento. Dois tipos de substrato esto presentes na rea: um substrato de tipo consistente, constituido por 89.7% de silte e argila e 10.3% de areia fina e outro de tipo no consistente contendo 74.5% de silte e argila e 25.5% de areia fina. O substrato de tipo no consistente apresenta quantidade de gua significativamente maior que o de tipo consistente. Mytella guyanensis vive enterrada no solo numa profundidade mxima de 1,0 cm, sempre envolvida pelos filamentos do bisso. A densidade mdia anual observada para a espcie foi de 5,2 indivduos por m; a distribuio espacial predominante foi do tipo agregado, sofrendo interferncia do tipo de substrato presente. Houve preferncia de fixao da espcie 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 presena de formas jovens foi assinalada em baixa frequncia em alguns meses do ano. A salinidade da gua estuarina variou de acordo com o regime pluviomtrico da regio, permanecendo dentro dos nveis de tolerncia da espcie. A fauna associada est representada por oito espcies de crustceos e por uma de molusco bivalve.

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

    Tanaka, Miho; Takahashi, Kazuya

    2013-04-01

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

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

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

    2016-02-01

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

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

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

    2012-12-01

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

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

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

    DANIEL R. OROS; Bassey O. Ekpo; Oyo-Ita, Orok E.; Bernd R. T. Simoneit

    2010-01-01

    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 ...

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

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

  18. Spatial and temporal variations of nitrous oxide flux between coastal marsh and the atmosphere in the Yellow River estuary of China

    Sun, Zhigao; Wang, Lingling; Mou, Xiaojie; Jiang, Huanhuan; Sun, Wanlong

    2013-01-01

    To investigate the spatial and seasonal variations of nitrous oxide (N2O) fluxes and understand the key controlling factors, we explored N2O fluxes and environmental variables in high marsh (HM), middle marsh (MM), low marsh (LM), and mudflat (MF) in the Yellow River estuary throughout a year. Fluxes of N2O differed significantly between sampling periods as well as between sampling positions. During all times of day and the seasons measured, N2O fluxes ranged from −0.0051 to 0.0805 mg N2O m−2...

  19. Morphological description of the Genus Skeletonema(Bacillariophyceae in Yangtze River Estuary,China

    WU Bo

    2013-02-01

    Full Text Available We examined the morphology of Skeletonema species occurring in Yangtze River Esturary by the light microscopy (LM and scanning electron microscopy (SEM .Two species,Skeletonema costatum(Greville Cleve and Skeletonema marinoi Sarno et Zingone,were discriminated in the genus Skeletonema.Of S.costatum,cell diameters are 6.3-15.1 μm and pervalvar axes are 7.7-11 μm.In S.marinoi,cell diameters are 4.6-11.2 μm and pervalvar axes are 11.7-12.2 μm. S.costatum is widely distributed in all seasons,while S.marinoi is only occurred in spring.

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

    Fok, Lincoln; Cheung, P K

    2015-10-15

    Large plastic (>5mm) and microplastic (0.315-5mm) debris were collected from 25 beaches along the Hong Kong coastline. More than 90% consisted of microplastics. Among the three groups of microplastic debris, expanded polystyrene (EPS) represented 92%, fragments represented 5%, and pellets represented 3%. The mean microplastic abundance for Hong Kong was 5595items/m(2). This number is higher than international averages, indicating that Hong Kong is a hotspot of marine plastic pollution. Microplastic abundance was significantly higher on the west coast than on the east coast, indicating that the Pearl River, which is west of Hong Kong, may be a potential source of plastic debris. The amounts of large plastic and microplastic debris of the same types (EPS and fragments) were positively correlated, suggesting that the fragmentation of large plastic material may increase the quantity of beach microplastic debris. PMID:26233305

  1. Soil organic matter and soil acidity in Mangrove areas in the river Paraiba Estuary, Cabedelo, Paraiba, Brazil

    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.

  2. Profile of trace metals accumulation in core sediment from Seine river estuary (docks basin).

    Hamzeh, Mariam; Ouddane, Baghdad; El-Daye, Mirna; Halwani, Jalal

    2013-01-01

    The Seine is one of the most polluted rivers in Europe with respect to potentially harmful elements. It receives effluents from the upstream Paris urban and industrial area, and also local inputs from the heavily industrialized Rouen and Le Havre regions. The present study deals with this environmental topic and the concentrations of Cd, Ni, Pb, Hg, Zn and Cu were determined in sediment cores collected in the docks basin of Rouen harbour in 2008. The intensity of metal pollution during recent decades was evaluated using an enrichment factor (EF) and a geoaccumulation index (Igeo). The results of vertical distribution showed that the metal pollution in the past is much higher than in the surface sediment. Mercury was found to be the heaviest pollutant (with Igeo and EF exceeding 4 and 20, respectively), and Cd and Pb were the second most important pollutants. A slight contamination in Ni was observed with very low Igeo values. To estimate the sediment toxicity, simultaneously extracted metals/acid volatile sulfides ratio (SEM/AVS) was calculated. Low values of the toxicity index SEM/AVS were observed in the core sediments indicating the inexistence of metal potential toxicity. Also the concentrations of these trace metals were lower than the probable effect concentration values reported as consensus-based sediment quality guidelines for fresh water ecosystems. PMID:24191442

  3. Coupling the chemical dynamics of carbonate and dissolved inorganic nitrogen systems in the eutrophic and turbid inner Changjiang (Yangtze River Estuary

    W.-D. Zhai

    2015-04-01

    Full Text Available To better understand biogeochemical processes controlling CO2 dynamics in those eutrophic large-river estuaries and coastal lagoons, we investigated surface water carbonate system, nutrients, and relevant hydrochemical parameters in the inner Changjiang (Yangtze River Estuary, covering its channel-like South Branch and the lagoon-like North Branch, shortly after a spring-tide period in April 2010. In the North Branch, with a water residence time of more than 2 months, biogeochemical additions of ammonium (7.4 to 65.7 μmol kg−1 and alkalinity (196 to 695 μmol kg−1 were detected along with high salinity of 4.5 to 17.4. In the South Branch upper-reach, unusual salinity values of 0.20 to 0.67 were detected, indicating spillover waters from the North Branch. The spillover waters enhanced the springtime Changjiang export fluxes of nutrients, dissolved inorganic carbon, and alkalinity. And they affected the biogeochemistry in the South Branch, by lowering water-to-air CO2 flux and continuing the nitrification reaction. In the North Branch, pCO2 was measured from 930 to 1518 μatm at the salinity range between 8 and 16, which was substantially higher than the South Branch pCO2 of 700 to 1100 μatm. Based on field data analyses and simplified stoichiometric equations, we suggest that the North Branch CO2 productions were quantified by biogeochemical processes combining organic matter decomposition, nitrification, CaCO3 dissolution, and acid-base reactions in the estuarine mixing zone. Although our study is subject to limited temporal and spatial coverage of sampling, we have demonstrated a procedure to quantificationally constrain net CO2 productions in eutrophic estuaries and/or coastal lagoons, by coupling the chemical dynamics of carbonate and dissolved inorganic nitrogen systems.

  4. Natural activity in Hudson River estuary samples and their influence on the detection limits for gamma emitting radionuclides using NaI gamma spectrometry

    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.)

  5. n-alkanes as indicators of natural and anthropogenic organic matter sources in the Siak River and its estuary, E Sumatra, Indonesia.

    Liebezeit, Gerd; Wöstmann, Ralf

    2009-09-01

    Along the Siak River and its estuary a total of 100 sediment and 57 plant samples were taken for the analysis of n-alkanes from 2003 to 2005. Sediment n-alkanes exhibit in the majority of samples a pronounced odd over even predominance with maxima at C29 and C31 indicative of a plant origin. Plant n-alkanes analysed have chain lengths up to C39. These compounds are also present in the river sediments. In some plants the Carbon Preference Index (CPI) has extremely low values normally only found in petroleum-contaminated samples. A distinction between vegetation- and petroleum-derived n-alkanes is therefore only possible by a combination of CPI and and the absence/presence of a prominent unresolved complex mixture. Based on these criteria only a limited number of the 100 sediments analysed exhibit clear indications of a petroleum contamination. PMID:19448964

  6. Dynamics of nitrous oxide reductase genes (nosZ) in intertidal rocky biofilms and sediments of the Douro River estuary (Portugal), and their relation to N-biogeochemistry.

    Magalhes, C; Bano, N; Wiebe, W J; Bordalo, A A; Hollibaugh, J T

    2008-02-01

    In this study, temporal variability of nosZ genotypes was evaluated in two intertidal rocky biofilms and two intertidal sediment sites of the Douro River estuary, Portugal. The results were compared to rates of key N-cycle processes and environmental variables to examine possible links between denitrifier community dynamics and N biogeochemistry. Genetic heterogeneity of the nosZ gene was evaluated by terminal restriction fragment length polymorphism analysis (T-RFLP) and by sequencing cloned nosZ gene fragments. Phylogenetic analysis showed that the majority of the nosZ genes detected were most similar to nosZ genes from isolates affiliated with alpha-subclass of the class Proteobacteria. Results revealed low nosZ genotype richness, and hierarchical cluster analysis showed significant differences in the composition of denitrifier communities that inhabit different intertidal environments of the Douro River estuary. Monthly surveys of nosZ genotypes from sandy sediments showed that, while the same T-RFLP peaks were present in all samples, shifts in the relative peak areas of the different nosZ genotypes occurred. Canonical correspondence analysis, based on data from the monthly survey, revealed a strong relationship between the relative peak areas of some T-RFLP operational taxonomic units (OTUs) with denitrification rate and NO3- availability. Results suggest that denitrifiers with specific nosZ genotypes (OTUs) have competitive advantage over others when NO3- fluctuates in the system; these fluctuations reflect, in turn, variability in denitrification rates. PMID:17604988

  7. Model Behavior and Sensitivity in an Application of the Cohesive Bed Component of the Community Sediment Transport Modeling System for the York River Estuary, VA, USA

    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.

  8. Living in an estuary: Commerson's dolphin (Cephalorhynchus commersonii (Lacpde, 1804, habitat use and behavioural pattern at the Santa Cruz River, Patagonia, Argentina

    Rocio Loizaga de Castro

    2013-11-01

    Full Text Available Commerson's dolphins, Cephalorhynchus commersonii, suffer bycatch in fisheries and are target of dolphin-watching activities along Patagonia. Here we described dolphins' habitat use and behavioural pattern at the estuary of Santa Cruz River. Behavioural observations were made from vantage points using a spotting scope. Boat surveys were conducted randomly from Puerto Santa Cruz to the mouth of the river to analyze the habitat use. The survey area was divided into 1 km cells and characterized with depth and benthic slope. The described behaviours for the Commerson's dolphin were: travelling, slow travelling, milling, resting, socializing, stationary swimming and diving. A new behavioural context was assigned to diving, a behaviour that showed a high frequency during downing tide, suggesting a benthic foraging strategy. Additionally, we found a strong influence of the tide on Commerson's dolphin behaviour. Habitat use models indicated that dolphins prefer shallow water inside the estuary. The knowledge of the behavioural patterns and the habitat use of these endemic species, in this unexplored area, provide tools for management and conservation purposes.

  9. Three dimensional model evaluation of physical alterations of the Caloosahatchee River and Estuary: Impact on salt transport

    Sun, Detong; Wan, Yongshan; Qiu, Chelsea

    2016-05-01

    Numerical hydrodynamic modeling provides quantitative understanding of how physical alterations of an estuary may alter the waterbody hydrodynamics and the rate of mixing with the ocean. In this study, a three dimensional hydrodynamic model (CH3D) was used to compare simulated salinities between the existing condition and five historical cases representing varying physical alterations of the Caloosahatchee Estuary involving (1) removal of the headwater structure (S-79); (2) removal of the downstream causeway to Sanibel Island; (3) backfilling an oyster bar near the estuary month; (4) refilling the navigation channel; and (5) the pre-development bathymetric condition. The results suggested that some alterations including the Sanibel Causeway, backfilling the oyster bar and the S-79 structure may have some local effects but did not change estuarine salinity structure significantly. Refilling the navigation channel had a more profound effect, resulting in a dry season salinity reduction of about 5 when compared with the existing condition. The reduced salt transport was more pronounced with the pre-development bathymetry because the estuary as a whole was much shallower than today. The significant system-wide increase in salt transport caused by the historic dredging of the navigation channel in the Caloosahatchee Estuary has significant implications in the development of attainable environmental flow targets for protecting the estuarine ecosystem.

  10. Characterization of heavy-metal contamination in surface sediments of the Minho river estuary by way of factor analysis.

    Mil-Homens, M; Costa, A M; Fonseca, S; Trancoso, M A; Lopes, C; Serrano, R; Sousa, R

    2013-05-01

    Surface sediments were collected in August 2009 from 49 sites along the Minho estuary (between Tui and Caminha) and analyzed for grain size, organic carbon (Corg) and total nitrogen (Ntot) contents, and major (silicon [Si], aluminum [Al], iron [Fe], calcium [Ca], magnesium [Mg], sodium [Na], potassium [K], titanium [Ti], and mangesese [Mn]) and trace element (arsenic [As], chromium [Cr], copper [Cu], mercury [Hg], lithium [Li], lead [Pb], rubidium [Rb], tin [Sn], and zinc [Zn]) concentrations. Factor analysis was used to decrease 22 selected variables into 4 factors accounting for 85.9 % of the total variance explained, suggesting distinct elemental sources or sediment components affecting their spatial distributions. Although factors 1 (detrital component; elements strongly associated with fine- [Na, Mg, Ti, Li, Cr, Cu, Fe, Al, Zn, Ca, and As] and coarse-grained sediments [Si, K, Rb; mean grain-size [MGS]) and 3 (Fe-Mn oxyhydroxide sediment component; Fe, Mn, As, fine fraction) are interpreted as reflecting predominance of natural contributions, factors 2 (urban and industrial contamination: sediment components [Pb, Hg, organic carbon [Corg], total nitrogen [Ntot] and 4 (components associated with contamination by nautical activities; the association of tin [Sn] and calcium [Ca]) seem to indicate anthropogenic contributions). Nevertheless, the influence of elemental contributions derived from tungsten (W)-Sn mineralizations and those resulting from mining activities can also contribute to the obtained geochemical associations and should be considered. Spatial distribution of dominant factor scores shows the dominance of factors 2 and 4 between Tui and Vila Nova de Cerveira, whereas samples dominated by factors 3 and 1 are found between Ilha da Boega and Seixas and in the Caminha areas, respectively. Despite the dominance of factor score 1 in the Caminha area, the distribution pattern of dominant factor scores shows samples dominated by other factor scores that can be explained by dredging activities in this river sector that restore ancient sedimentary characteristics or expose contaminated sediments. Through the identification of sample locations dominated by factors associated with contamination, it will be possible to select them as priority areas where new environmental (e.g., toxicity tests, organic Sn compounds, tracers of sewage contamination) studies should be implemented in the future. PMID:23299253

  11. Sources and accumulation of organic carbon in the Pearl River Estuary surface sediment as indicated by elemental, stable carbon isotopic, and carbohydrate compositions

    He, B.; Dai, M.; Huang, W.; Liu, Q.; Chen, H.; Xu, L.

    2010-10-01

    Organic matter in surface sediments from the upper reach of the Pearl River Estuary and Lingdingyang Bay, as well as the adjacent northern South China Sea shelf was characterized using a variety of techniques, including elemental (C and N) ratio, bulk stable organic carbon isotopic composition (δ13C), 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. δ13C 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 δ13C, 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 δ13C 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.

  12. Sources and accumulation of organic carbon in the Pearl River Estuary surface sediment as indicated by elemental, stable carbon isotopic, and carbohydrate compositions

    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 (δ13C, 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. δ13C 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 δ13C, 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 δ13C 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.

  13. Caracterizacin hidrogrfica del estuario del ro Valdivia, centro-sur de Chile / Hydrographic features of Valdivia river estuary south-central Chile

    Jos, Garcs-Vargas; Marcela, Ruiz; Luis Miguel, Pardo; Sergio, Nuez; Ivn, Prez-Santos.

    2013-03-01

    Full Text Available La costa sureste del Ocano Pacfico entre 37 y 41S, se caracteriza por la presencia de un gran nmero de estuarios micromareales (rango mareal menor a 2 m). Uno de los estuarios ms importantes dentro de estas latitudes es el estuario del ro Valdivia, cuya estructura y dinmica termal y halina e [...] s poco conocida. Mediante mediciones hidrogrficas de temperatura y salinidad tomadas durante un ciclo estacional anual y el anlisis de sus principales forzantes (marea, caudal del ro, vientos y radiacin solar) se explica la variabilidad as como sus cambios en la estratificacin vertical. El anlisis de la estructura termohalina de la columna de agua revel que el estuario vari estacionalmente comportndose como un estuario de cua salina en invierno y primavera producto del mayor caudal de los ros afluentes, mientras que en verano y otoo se comport como parcialmente mezclado, producto del menor caudal de los ros. En invierno y primavera la columna de agua present inversin trmica, la cual fue asociada a prdida de calor superficial y a la adveccin sub-superficial de aguas clidas desde el ocano adyacente hacia el interior del estuario que no se mezclaron con las de la superficie debido a la intensa estratificacin salina. El cambio en el rgimen estuarino de cua salina a parcialmente mezclado segn la estacin del ao y presencia de la inversin trmica estacional, son caractersticas hidrogrficas necesarias tanto para la implementacin de esfuerzos de conservacin de hbitat vulnerables presentes en la zona (reas de crianza de juveniles de especies explotadas), como para la utilizacin de este sistema para actividades de acuicultura y manejo de recursos marinos. Abstract in english The area between 37 and 41S 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.

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

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

    2010-01-01

    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...

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

    C. A. SCHETTINI

    2000-12-01

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

  16. Levels of C{sub 10}-C{sub 13} polychloro-n-alkanes in marine mammals from the Arctic and the St. Lawrence River estuary

    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.

  17. Salinity characteristics and distribution and effects of alternative plans for freshwater withdrawal, Little Manatee River estuary and adjacent areas of Tampa Bay, Florida

    Fernandez, Mario

    1985-01-01

    The Little Manatee River, a coastal stream that empties into Tampa Bay, Florida, may be used as a source of freshwater. Reduction of streamflow will result in upstream movement of saltwater in the stream. Data on streamflow, tide stage, and specific conductance describe the salinity distribution of the estuary. Vertical conductivity profiles indicate that the river is vertically homogeneous during low flow. The maximum upstream location of the saltwater-freshwater interface (800 micromhos) in the river was described by multiple regression analysis involving mean daily streamflow and high-high tide. The coefficient of determination is 0.94 with a root mean square error of + or - 0.4 mile. The location on the river where the estuarine system ends and the riverine system begins is at about 9.9 miles above the reference station at Shell Point. Duration analysis of conductivity indicates that the maximum upstream location of the interface exceeded 9.7 miles about 17 percent of the days for the period of study. Reduction by 50 percent of streamflow for the 90day, 2-year and 20-year recurrence-interval low flow would relocate the maximum intrusion of the interface at the 2-year and 20-year flows upstream by 0.7 and 0.2 mile, respectively. (USGS)

  18. Artificial radionuclides in French estuaries

    Measurements were made of 238Pu, sup(239-240)Pu, 241Am, 137Cs, 144Ce, 106Ru, 125Sb and 131I in the principal rivers and estuaries of France (Seine, Loire, Gironde, Rhone). The mean specific activities due to sup(239-240)Pu in river water suspensions (5 to 10 fCi/g) are very little affected by releases from nuclear power stations. The unexpectedly high 238Pu/sup(239-240)Pu activity ratios (0.15 to 0.25) found in media subject only to atmospheric fall-out results from fractionation in the catchment areas. The high artificial radionuclide activities measured in the Seine estuary are attributed to releases from Windscale and, above all, from La Hague. The 137Cs found in Gironde river water remains associated with particles in the estuary. It decreases downstream by ion exchange in the estuary of the Loire, whereas in the Seine estuary the values recorded are higher than upstream owing to the effects of marine contamination. Particulate sup(239-240)Pu increases in all cases between the river and the estuary, a result which is in line with its frequent deficit in solution. However, the transfer of dissolved fluvial sup(239-240)Pu (0.05 to 0.2 fCi/ltr) cannot account for the excess in the particulate phase, the origin of which is ascribed to dissolved marine plutonium. (author)

  19. Satellite Remote Sensing of Chlorophyll a in Support of Nutrient Management in the Neuse and Tar-Pamlico River Estuaries

    The North Carolina Environmental Management Commission (EMC) has adopted as a water quality standard that chlorophyll a concentration should not exceed 40 ug/L in sounds, estuaries and other slow-moving waters. Exceedances require regulators to develop a Total Maximum Daily Limit...

  20. Potential remobilization of 137Cs, 60Co, 90Tc, and 90Sr from contaminated Mayak sediments in river and estuary environments.

    Standring, William J F; Oughton, Deborah H; Salbu, Brit

    2002-06-01

    Following 50 years of nuclear production at Mayak PA, sediments in storage reservoirs are significantly contaminated. Dam failure or flooding could potentially transport large amounts of sediments, via rivers, to the Ob estuary and Kara Sea. The objectives of this work were to investigate fresh and seawater remobilization of 137Cs, 50Co, 99Tc, and 90Sr from contaminated Reservoir 10 sediments. Sediments were extracted sequentially using synthetic Techa freshwater, seawater, and chemical reagents with increasing dissolution powers. 137Cs and 90Sr freshwater distribution coefficients (apparent Kd) agreed quite well with published values; values for 99Tc were higher and values for 60Co were lower than expected. In seawater, mean apparent Kd values decreased by 94, 77, 48, and 73% (137Cs, 60Co, 99Tc, and 90Sr, respectively), indicating increased radionuclide mobility. Remobilization in seawater was 5, 15, 1, and 23% of total activities (i.e., releases of 165, 11, 0.3, and 170 kBq kg(-1) d.w.) for 137Cs, 60Co, 99Tc, and 90Sr, respectively. 137Cs and 99Tc were strongly bound to sediments (60% and 80%, respectively). 60Co and 90Sr were more mobile (70% reversibly bound). In conclusion, Mayak Reservoir sediments could potentially contaminate the Ob estuary due to remobilization of sediment-held radionuclides upon contact with seawater. PMID:12075786

  1. 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

    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.

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

    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. - Highlights: • EPA 16 PAHs contributed a small amount of total PAHs. • Alkyl PAHs showed different behaviors from parent PAHs. • High weight PAHs preferably indicated riverine input. • PAHs distribution in sediment was related with the suspended particle deposition. - Suspended particular matter played a very important role in distribution of PAHs in tide-dominated estuary and alkyl PAHs showed different behavior from parent PAHs

  3. Design and Analysis of Salmonid Tagging Studies in the Columbia Basin : Evaluating Wetland Restoration Projects in the Columbia River Estuary using Hydroacoustic Telemetry Arrays to Estimate Movement, Survival, and Residence Times of Juvenile Salmonids, Volume XXII (22).

    Perry, Russell W.; Skalski, John R.

    2008-08-01

    Wetlands in the Columbia River estuary are actively being restored by reconnecting these habitats to the estuary, making more wetland habitats available to rearing and migrating juvenile salmon. Concurrently, thousands of acoustically tagged juvenile salmonids are released into the Columbia River to estimate their survival as they migrate through the estuary. Here, we develop a release-recapture model that makes use of these tagged fish to measure the success of wetland restoration projects in terms of their contribution to populations of juvenile salmon. Specifically, our model estimates the fraction of the population that enter the wetland, survival within the wetland, and the mean residence time of fish within the wetland. Furthermore, survival in mainstem Columbia River downstream of the wetland can be compared between fish that remained the mainstem and entered the wetland. These conditional survival estimates provide a means of testing whether the wetland improves the subsequent survival of juvenile salmon by fostering growth or improving their condition. Implementing such a study requires little additional cost because it takes advantage of fish already released to estimate survival through the estuary. Thus, such a study extracts the maximum information at minimum cost from research projects that typically cost millions of dollars annually.

  4. Distribution and behaviour of 137Cs in nearshore sediments of the northern Adriatic and at the Adige River estuary, northern Italy

    This paper reports the results of determinations of 137Cs and other radionuclides in bottom sediments and suspended matter collected in a coastal zone of the northern Adriatic. The activity, behaviour and distribution of 137Cs and some natural radionuclides were determined in materials sampled up to 1984. Various artificial radionuclides were detected in samples collected in 1986. The study of the distribution of 137Cs as a function of sediment properties showed that this radionuclide preferentially accumulates in the finest particles and is taken up by adsorption surface processes. This radioisotope has been used as a tracer for recent sedimentary processes occurring in the study area for predicting the fate of other inorganic and organic pollutants reaching the sediments by natural processes. Exceptionally high values of radioactivity were observed after the Chernobyl accident in the estuary of the Adige River, particularly in suspended matter. (author)

  5. Protist 18S rRNA gene Sequence Analysis Reveals Multiple Sources of Organic Matter Contributing to Turbidity Maxima of the Columbia River Estuary

    Herfort, Lydie; Peterson, Tawnya D.; McCue, Lee Ann; Zuber, Peter A.

    2011-10-05

    The Columbia River estuary is traditionally considered a detritus-based ecosystem fueled in summer by organic matter (OM) from expired freshwater diatoms. Since Estuarine Turbidity Maxima (ETM) are sites of accumulation and transformation of this phytoplankton-derived OM, to further characterize the ETM protist assemblage, we collected in August 2007 bottom waters throughout an ETM event, as well as surface water during the peak of bottom turbidity, and performed biogeochemical, microscopic and molecular (18S rRNA gene clone libraries) analyses. These data confirmed that the majority of the particulate OM in ETMs is derived from chlorophyll a-poor particulate organic carbon tagged by DNA too damaged to be detected by molecular analysis.

  6. Plutonium, cesium and uranium series radionuclides in the Hudson River estuary and other environments. Annual technical progress report, 1 December 1980-30 November 1981

    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

  7. 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

    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.

  8. Bacterioplankton dynamics along the gradient from highly eutrophic Pearl River Estuary to oligotrophic northern South China Sea in wet season: implication for anthropogenic inputs.

    Zhou, Weihua; Long, Aimin; Jiang, Tao; Chen, Shaoyong; Huang, Liangmin; Huang, Hui; Cai, Chuanghua; Yan, Yan

    2011-04-01

    Bacterioplankton abundance (BA) and biomass (BB) from the eutrophic Pearl River Estuary (PRE) to the oligotrophic northern South China Sea (NSCS) were studied in the wet season. BA was significantly higher (p 100 μM and PO₄ > 1 μM) resulted in high chl a and BB, whereas nutrient-depleted offshore waters (DIN 26 °C) was not the controlling factor of BA. BB was significantly correlated with chl a biomass both in PRE and NSCS. The bacteria to phytoplankton biomass (BB/PB) ratio increased clearly along the gradient from near-shore PRE (0.15) to offshore CSNP (0.93) and deep OP (2.75), indicating the important role of small cells in the open ocean compared to estuarine and coastal zones. PMID:21316714

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

    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.

  10. Linking Species Traits to the Abiotic Template of Flowing Waters: Contrasting Eco physiologies Underlie Displacement of Zebra Mussels by Quagga Mussels in a Large River-Estuary

    Casper, A. F.

    2005-05-01

    The St. Lawrence River-Estuary was the gateway of entry for dreissenids to North America and holds some of the oldest populations. The St. Lawrence also has four distinct physical-chemical water masses (a regional scale abiotic template) that both species inhabit. Despite their ecological similarities, quagga mussels are supplanting zebra mussels in much of their shared range. In order to try to better understand the changing distributions of these two species we compared glycogen, shell mass and tissue biomass in each of the water masses. This comparative physiological combined with experimental approaches (estuarine salinity experiments and reciprocal transplants) showed that while quagga mussels should dominate in most habitats, that abiotic/bioenergetic constraints in two regions (the Ottawa River plume and the freshwater-marine transition zone) might prevent them from dominating these locations. These findings are an example of how the interaction of landscape scale abiotic heterogeneity and a species-specific physiology can have strong impacts of distribution of biota large rivers.

  11. Total and labile metals in surface sediments of the tropical river-estuary system of Marabasco (Pacific coast of Mexico): Influence of an iron mine.

    Marmolejo-Rodríguez, Ana Judith; Prego, Ricardo; Meyer-Willerer, Alejandro; Shumilin, Evgueni; Cobelo-García, Antonio

    2007-01-01

    Marabasco is a tropical river-estuary system comprising the Marabasco river and the Barra de Navidad Lagoon. The river is impacted by the Peña Colorada iron mine, which produces 3.5 million tons of pellets per year. Thirteen surface sediment samples were collected in May 2005 (dry season) in order to establish background levels of Al, Cd, Co, Cu, Fe, Ni, Pb, and Zn in the system and to ascertain the potential mobility of metals in the sediments. Analyses were carried out in the fraction finer than 63 microm, and labile metals extracted according the BCR procedure. Certified reference materials were used for validation of methods. Total concentrations of Cd, Co, Cu, Ni, Pb, and Zn were in the range of 0.05-0.34, 6-95, 0.7-31, 9-26, 2-18, and 53-179 mgkg(-1), respectively; Al and Fe ranges of 24-127, and 26-69 mgg(-1) correspondingly. Cadmium was found to be significantly labile in the sediments (20-100%), followed by Co (0-35%), Ni (3-16%) and Zn (0-25%), whereas the labile fraction for Cu, Fe and Pb was almost negligible (<4%). According with the total metal concentrations, background levels and normalised enrichment factors (NEF) of the metals studied, the impact of the Peña Colorada iron mine on the Marabasco system is lower than expected when compared with other similar World systems influenced by mining activities. PMID:17997460

  12. Total and labile metals in surface sediments of the tropical river-estuary system of Marabasco (Pacific coast of Mexico): Influence of an iron mine

    Marmolejo-Rodriguez, Ana Judith [Centro Interdisciplinario de Ciencias Marinas, (IPN) La Paz, B.C.S. (Mexico); Instituto de Investigaciones Marinas, (CSIC), Vigo (Spain)], E-mail: amarmole@ipn.mx; Prego, Ricardo [Instituto de Investigaciones Marinas, (CSIC), Vigo (Spain); Meyer-Willerer, Alejandro [Centro Universitario de Investigaciones Oceanologicas, Universidad de Colima, Col. (Mexico); Shumilin, Evgueni [Centro Interdisciplinario de Ciencias Marinas, (IPN) La Paz, B.C.S. (Mexico); Cobelo-Garcia, Antonio [Instituto de Investigaciones Marinas, (CSIC), Vigo (Spain)

    2007-07-01

    Marabasco is a tropical river-estuary system comprising the Marabasco river and the Barra de Navidad Lagoon. The river is impacted by the Pena Colorada iron mine, which produces 3.5 million tons of pellets per year. Thirteen surface sediment samples were collected in May 2005 (dry season) in order to establish background levels of Al, Cd, Co, Cu, Fe, Ni, Pb, and Zn in the system and to ascertain the potential mobility of metals in the sediments. Analyses were carried out in the fraction finer than 63 {mu}m, and labile metals extracted according the BCR procedure. Certified reference materials were used for validation of methods. Total concentrations of Cd, Co, Cu, Ni, Pb, and Zn were in the range of 0.05-0.34, 6-95, 0.7-31, 9-26, 2-18, and 53-179 mg kg{sup -1}, respectively; Al and Fe ranges of 24-127, and 26-69 mg g{sup -1} correspondingly. Cadmium was found to be significantly labile in the sediments (20-100%), followed by Co (0-35%), Ni (3-16%) and Zn (0-25%), whereas the labile fraction for Cu, Fe and Pb was almost negligible (<4%). According with the total metal concentrations, background levels and normalised enrichment factors (NEF) of the metals studied, the impact of the Pena Colorada iron mine on the Marabasco system is lower than expected when compared with other similar World systems influenced by mining activities.

  13. Total and labile metals in surface sediments of the tropical river-estuary system of Marabasco (Pacific coast of Mexico): Influence of an iron mine

    Marabasco is a tropical river-estuary system comprising the Marabasco river and the Barra de Navidad Lagoon. The river is impacted by the Pena Colorada iron mine, which produces 3.5 million tons of pellets per year. Thirteen surface sediment samples were collected in May 2005 (dry season) in order to establish background levels of Al, Cd, Co, Cu, Fe, Ni, Pb, and Zn in the system and to ascertain the potential mobility of metals in the sediments. Analyses were carried out in the fraction finer than 63 μm, and labile metals extracted according the BCR procedure. Certified reference materials were used for validation of methods. Total concentrations of Cd, Co, Cu, Ni, Pb, and Zn were in the range of 0.05-0.34, 6-95, 0.7-31, 9-26, 2-18, and 53-179 mg kg-1, respectively; Al and Fe ranges of 24-127, and 26-69 mg g-1 correspondingly. Cadmium was found to be significantly labile in the sediments (20-100%), followed by Co (0-35%), Ni (3-16%) and Zn (0-25%), whereas the labile fraction for Cu, Fe and Pb was almost negligible (<4%). According with the total metal concentrations, background levels and normalised enrichment factors (NEF) of the metals studied, the impact of the Pena Colorada iron mine on the Marabasco system is lower than expected when compared with other similar World systems influenced by mining activities

  14. Anthropogenic 236U at Rocky Flats, Ashtabula river harbor, and Mersey estuary: three case studies by sector inductively coupled plasma mass spectrometry

    236U (t1/2=2.3x107 y) is formed as a result of thermal neutron capture by 235U. In naturally occurring U ores, where a high neutron flux is present from spontaneous fission of 238U, 236U/238U atom ratios are ?10-4 ppm. In the natural Earth's crust, unaffected by nuclear fallout, these ratios are expected to be on the order of 10-8 ppm. Reactor-irradiated U, however, exhibits high 236U/238U atom ratios approaching 104 ppm. As a result, the presence of very small quantities of reactor-irradiated U will significantly enhance the 'background' 236U/238U atom ratio. When sufficiently elevated 236U/238U ratios are present, the determination of 236U/238U by rapid inductively coupled plasma mass spectrometric (ICPMS) methods is attractive. We have used sector ICPMS at medium resolving power (R=3440) to measure 236U/238U atom ratios with a determination limit of 0.2 ppm. The limiting factors in the measurement are the 235U1H+ isobar and background signal at m/z 236 arising from the 238U+ peak tail. Based upon the analysis of replicates and considerations of possible systematic errors, uncertainties of 5% are found for 236U/238U atom ratios of 1-100 ppm. This procedure has been demonstrated in studies of anthropogenic 236U in the environment at three locations: (a) offsite soils from the vicinity of the Rocky Flats Environmental Technology site (Golden, Colorado, USA); (b) sediments from the Ashtabula River (Ohio, USA); and (c) sediments from the Mersey estuary (Liverpool, UK). In each of these three locations, definite plumes of elevated 236U/238U are identified and characterized. Maximum 236U/238U atom ratios observed in RFETS-vicinity soils, the Ashtabula River, and the Mersey Estuary are 2.8, 140, and 4.4 ppm, respectively

  15. Records of bulk organic matter and plant pigments in sediment of the "red-tide zone" adjacent to the Changjiang River estuary

    Kang, Zhenjun; Yu, Rencheng; Kong, Fanzhou; Wang, Yunfeng; Gao, Yan; Chen, Jianhua; Guo, Wei; Zhou, Mingjiang

    2016-01-01

    Cultural eutrophication caused by nutrient over-enrichment in coastal waters will lead to a cascading set of ecosystem changes and deleterious ecological consequences, such as harmful algal blooms (HABs) and hypoxia. During the past two decades since the late 1990s, recurrent large-scale HABs (red tides) and an extensive hypoxic zone have been reported in the coastal waters adjacent to the Changjiang River estuary. To retrieve the history of eutrophication and its associated ecosystem changes, a sediment core was collected from the "red-tide zone" adjacent to the Changjiang River estuary. The core was dated using the 210Pb radioisotope and examined for multiple proxies, including organic carbon (OC), total nitrogen (TN), stable isotopes of C and N, and plant pigments. An apparent up-core increase of OC content was observed after the 1970s, accompanied by a rapid increase of TN. The concurrent enrichment of δ13C and increase of the C/N ratio suggested the accumulation of organic matter derived from marine primary production during this stage. The accumulation of OC after the 1970s well reflected the significant increase of primary production in the red-tide zone and probably the intensification of hypoxia as well. Plant pigments, including chlorophyll a, β-carotene, and diatoxanthin, showed similar patterns of variation to OC throughout the core, which further confirmed the important contribution of microalgae, particularly diatoms, to the deposited organic matter. Based on the variant profiles of the pigments representative of different microalgal groups, the potential changes of the phytoplankton community since the 1970s were discussed.

  16. 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

    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 μg 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.

  17. 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

    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 μg 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 μg C (μg 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 μg C (μg Chl a)-1 L-1 in mixohaline zone (SSS > 20); accordingly, the carbon fixation per volume of seawater increased from 12.8 to 149 μg C L-1 h-1, and decreased to 14.3 μg C L-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.

  18. GDGTs of Marine Group II Archaea in the Pearl River Estuary: Toward a Better Understanding of the Bias of TEX86

    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.

  19. Potential mitigation approach to minimize salinity intrusion in the Lower Savannah River Estuary due to reduced controlled releases from Lake Thurmond

    Conrads, Paul A.; Greenfield, James M.

    2010-01-01

    The Savannah River originates at the confluence of the Seneca and Tugaloo Rivers, near Hartwell, Ga. and forms the State boundary between South Carolina and Georgia. The J. Strom Thurmond Dam and Lake, located 187 miles upstream from the coast, is responsible for most of the flow regulation that affects the Savannah River from Augusta to the coast. The Savannah Harbor experiences semi-diurnal tides of two high and two low tides in a 24.8-hour period with pronounced differences in tidal range between neap and spring tides occurring on a 14-day and 28-day lunar cycle. The Savannah National Wildlife Refuge is located in the Savannah River Estuary. The tidal freshwater marsh is an essential part of the 28,000-acre refuge and is home to a diverse variety of wildlife and plant communities. The Southeastern U.S. experienced severe drought conditions in 2008 and if the conditions had persisted in Georgia and South Carolina, Thurmond Lake could have reached an emergency operation level where outflow from the lake is equal to the inflow to the lake. To decrease the effect of the reduced releases on downstream resources, a stepped approach was proposed to reduce the flow in increments of 500 cubic feet per second (ft3/s) intervals. Reduced flows from 3,600 ft3/s to 3,100 ft3/s and 2,600 ft3/s were simulated with two previously developed models of the Lower Savannah River Estuary to evaluate the potential effects on salinity intrusion. The end of the previous drought (2002) was selected as the baseline condition for the simulations with the model. Salinity intrusion coincided with the 28-day cycle semidiurnal tidal cycles. The results show a difference between the model simulations of how the salinity will respond to the decreased flows. The Model-to-Marsh Decision Support System (M2MDSS) salinity response shows a large increase in the magnitude (> 6.0 practical salinity units, psu) and duration (3-4 days) of the salinity intrusion with extended periods (21 days) of tidal freshwater remaining in the system. The Environmental Fluid Dynamic Code (EFDC) model predicts increases in the magnitude of the salinity intrusion but only to 2 and 3 psu and the intrusion duration greater than a week. A potential mitigation to the increased salinity intrusion predicted by the M2MDSS would be to time pulses of increase flows to reduce the magnitude of the intrusion. Seven-day streamflow pulses of 4,500 ft3/s were inserted into the constant 3,100 ft3/s streamflow condition. The streamflow pulses did substantially decrease the magnitude and duration of the salinity intrusion. The result of the streamflow pulse scenario demonstrates how alternative release patterns from Lake Thurmond could be utilized to mitigate potential salinity changes in the Lower Savannah River Estuary.

  20. Studies of speciation and migration pathways of Cs-137 and plutonium isotopes in the system river Ob-estuary-Kara sea

    Full text: The Arctic Basin plays a very impotant role inpreservation of ecological equilibrium on earth. This area is a region of formation of global atmospheric processes and it is the natural filter for the contaminated streams. The sources of contamination of Arctic Basin are different and world spread. They could be local like direct dumps including industrial pollution and operation of vehicles and global ones like Nothern hemisphere fallout or trans-boundary transfer. One of the most important sources of radioactive pollution of Russian Arctic area is the Great Siberian Rivers runoff. PO Mayak is wery well-known reprocessing plant, which can be very dangerous contaminator due to connection with Kara Sea throw rivers Techa-Iset-Tobol-Ob water system. On the other hand functioning of Krasnoyarsk mining industrial plant leads to radionuclide contamination of Yenisey river and as a consequence to pollution of Arctic Basin. For researching speciation and migration of man-made radionuclides in the water environment determinations of plutonium-239, 240 and cesium-137 activities have been carried out. The region under investigation was Ob River-mixing zone-adjunct part of Kara Sea. In order to study geochemical behaviour data on cesium-137 and plutonium-239 activities in different fractions of bottom sediments were obtained. For separation of special types of contamination from various sources plutonium-240/plutonium-239 isotopic ratios were studied. Numerous techniques including ?-ray, ?-ray spectrometry, icp-ms and a-ms have been used. Summarized the researches, carried out during last years, it has shown a significant difference in behaviour and migration of plutonium and cesium isotopes in the system river-estuary-adjunct part of the sea

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

    Kessarkar, P.M.; Shynu, R.; Rao, V.P.; Chong, F.; Narvekar, T.; Zhang, J.

    based on the EF of metals suggested by Sutherland (2000) were also shown in Fig. 8. Total nitrogen content and nitrogen isotopes were determined from the powdered samples, whereas particulate organic carbon and stable organic carbon isotopes were... on replicates of laboratory standards was ±0.3‰ for δ13C and ± 0.2‰ for δ15N. Distribution of total organic carbon and total nitrogen and their isotopes were shown Fig. 9 and Table 3. Results Sampling stations in the Mandovi estuary are from the main...

  2. Distribution of organochlorine pesticides in sediments from Yangtze River Estuary and the adjacent East China Sea: implication of transport, sources and trends.

    Zhou, Shanshan; Yang, Huayun; Zhang, Anping; Li, Yi-Fan; Liu, Weiping

    2014-11-01

    Thirty-eight surface sediments and two sediment cores were collected from Yangtze River Estuary (YRE) and adjacent East China Sea (ECS) to study the distribution patterns, origins, potential transport and burden of organochlorine pesticides (OCPs) in the marginal sea. Residues of OCPs ranged from 0.190 to 5.17 ng g(-1) dry weight with a distinct "band type" pattern under the control of Yangtze River inputs and ECS circulation system. Differences in transmission media and redox conditions in situ respectively resulted in the divergent distributions of α/β-HCH and DDD/DDE. The compositional pattern analysis implied that OCPs in the inner shelf of ECS were derived from both "weathered" and fresh sources, whereas those in the outer shelf of ECS had undergone high metabolism. Concurrent with the land-sea migration, vertical profiles of sediment cores showed increasing trends or rebound since the 1990s, characteristic of two evident "jumps" of DDE+DDD/DDT and DDT/DDE ratios. Moreover, the primary distribution pattern founded for HCHs and the considerable mass inventories calculated (6.20 metric tones for OCPs) together suggested that the contaminated sediments in the studied area to be a potential source of OCPs to the global ocean. PMID:25113180

  3. Activity concentration and spatial distribution of radionuclides in marine sediments close to the estuary of Shatt al-Arab/Arvand Rud River, the Gulf.

    Patiris, D L; Tsabaris, C; Anagnostou, C L; Androulakaki, E G; Pappa, F K; Eleftheriou, G; Sgouros, G

    2016-06-01

    Tigris and Euphrates rivers both emerge in eastern Turkey and cross Syria and Iraq. They unite to Shatt al-Arab/Arvand Rud River and discharge in Arabic/Persian Gulf. The activity concentration of natural and anthropogenic radionuclides was measured during the August of 2011 in a number of surficial sediment samples collected from the seabed along an almost straight line beginning near the estuary mouth and extending seaward. The results exhibited low activity concentration levels and an almost homogeneous spatial distribution except locations where sediment of biogenic origin, poor in radionuclides, dilute their concentrations. Dose rates absorbed by reference marine biota were calculated by the ERICA Assessment Tool considering the contribution of 40 K. The results revealed a relatively low impact of 40 K mainly to species living in, on and close to the seabed. Also, statistical association of radionuclides with selected stable elements (Ca, Ba and Sr) did not indicate presence of by-products related with oil and gas exploitation and transportation activities. Moreover, a semi-empirical sedimentology model applied to reproduce seabed granulometric facies based entirely on radionuclides activity concentrations. PMID:26945883

  4. Sources and accumulation of organic carbon in the Pearl River Estuary surface sediment as indicated by elemental, stable carbon isotopic, and carbohydrate compositions

    B. He

    2010-04-01

    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 by a variety of techniques, including elemental (C and N, stable carbon isotopic (δ 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. δ13C 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 δ13C, 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 δ13C 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.

  5. 234Th and 7Be as Tracers for the Sources of Particles to the Turbidity Maximum of the Hudson River Estuary

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

    1999-11-01

    The natural radionuclides 234Th (half-life=241 days) and 7Be (half-life=533 days) were measured in suspended particles of the turbidity maximum zone of the lower Hudson River estuary during several tidal cycles in August 1995 in an effort to understand the dynamics and sources of particles to this zone. The relatively short half-lives and high particle reactivity of 234Th and 7Be, coupled with the spatially variable production of 234Th (from 238U, which varies conservatively with salinity in the Hudson), make these radionuclides useful tracers of particle dynamics. The activity ratio of 234Th xs/ 7Be reduces the effects of particle type, concentration and size on the individual activities and serves as an indicator of where in the estuary the particles were labelled with these radionuclides. Detailed sampling at three stations in the turbidity maximum during the course of a tidal cycle shows an average 234Th xs/ 7Be activity ratio of 1907. Comparable 234Th xs/ 7Be ratios in suspended particles from surface and bottom water with different salinities indicate that particles are mixed throughout the water column. Comparison of observed 234Th xs/ 7Be activity ratios with those calculated from models assuming that local processes dominate the tracer distributions suggests that particle residence times are short. However, the observed ratios are greater on average than those calculated, indicating the import of particles with higher ratios from the more saline reaches of the estuary. Estimates of the particle fluxes necessary to account for the observed 234Th/ 7Be activity ratios suggest that about 30% of the flux could arise from advective transport of particles into the turbidity maximum zone in association with the tidal circulation and the remainder is supplied from local resuspension. A sensitivity analysis shows that these estimates are dependent on the activity ratio in the suspended sediment reservoir and fluxes of radionuclides supplied by local resuspension. Variability in these factors gives rise to estimates of the advected flux that can vary from 24% to 59%.

  6. The transition from wave-dominated estuary to wave-dominated delta: The Late Quaternary stratigraphic architecture of Tiber River deltaic succession (Italy)

    Milli, Salvatore; D'Ambrogi, Chiara; Bellotti, Piero; Calderoni, Gilberto; Carboni, Maria Gabriella; Celant, Alessandra; Di Bella, Letizia; Di Rita, Federico; Frezza, Virgilio; Magri, Donatella; Pichezzi, Rita Maria; Ricci, Valeria

    2013-02-01

    This paper presents a detailed description of the stratigraphic architecture of the Late Pleistocene/Holocene Tiber delta succession in order to document the passage from wave-dominated estuary to wave-dominated delta in the broader context of Late Quaternary sea level fluctuations. This succession constitutes a sequence-stratigraphic unit known as Tiber Depositional Sequence (TDS), which was deposited during the last glacial-interglacial cycle (last 120 ka). Our study is based on the examination of an enormous amount of data derived from the stratigraphy of about 300 wells, petrographical and paleontological data (foraminifera, ostracoda, pollen, and plant macrofossils), 14C dating, and from the integration of geomorphological and geoarcheological data. Recently a 100 m deep core (Pesce Luna well) was studied through a multidisciplinary approach and a detailed description of sedimentary facies, foraminifer and ostracod assemblages, pollen and 14C dating is presented in this paper. The new data allowed to produce three new correlation panels and to describe in more detail, with respect to previous interpretations, the stratigraphic-depositional architecture of the TDS, which internally shows the preservation of sediment deposited during the early and late lowstand, the transgressive and the highstand systems tracts. Alluvial and coastal depositional systems characterize the early lowstand phase of the TDS, which developed during the eustatic sea-level fall between about 120 and 30-26 yr BP. During the late lowstand phase, which is characterized by stillstand and slow eustatic sea-level rise a prograding delta and an aggrading incised-valley fluvial fill developed. The Tiber incised valley was transformed into a wave-dominated estuary during the transgressive phase (TST), whereas a coastal-shelf sedimentation took place during the subsequent highstand phase (HST). This study confirms the lithofacies distribution resulting from transgression and infilling of the wave-dominated estuaries, but also shows how the transition to a wave-dominated delta, prograding at the time of sea-level highstand occurred. Changes in sediment input, climatic variations and, more recently, human activities played a major role in the development of the Tiber delta during the last 20,000 yr BP. In the last 3000 years a relationship between progradational phases of the delta and flood events of the Tiber river has been highlighted, suggesting also the formation and merging of barrier-spits to the mainland.

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

    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 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

  8. Nutrient characteristics in the Yangtze River Estuary and the adjacent East China Sea before and after impoundment of the Three Gorges Dam.

    Chai, Chao; Yu, Zhiming; Shen, Zhiliang; Song, Xiuxian; Cao, Xihua; Yao, Yun

    2009-08-01

    From November 2002 to 2006, five cruises were undertaken in the Yangtze River Estuary and the adjacent East China Sea to compare the nutrient concentrations, ratios and potential nutrient limitation of phytoplankton growth before and after impoundment (June 2003) of the Three Gorges Dam (TGD). Concentrations of dissolved inorganic nitrogen (DIN), soluble reactive phosphorus (SRP) and total nitrogen (TN) exhibited an increasing trend from 2002 to 2006. In contrast, total phosphorus (TP) concentration exhibited a decreasing trend. The mean concentrations of DIN, SRP, and TN in the total study area increased from 21.4 microM, 0.9 microM, and 41.8 microM in 2002 to 37.5 microM, 1.3 microM, and 82.2 microM in 2006, respectively, while TP decreased from 2.1 microM to 1.7 microM. The concentration of dissolved reactive silica (DRSi) had no major fluctuations and the differences were not significant. The mean concentration of DRSi in the total study area ranged from 52.5 to 92.3 microM. The Si:N ratio decreased significantly from 2.7 in 2002 to 1.3 in 2006, while TN:TP ratio increased from 22.1 to 80.3. The area of potential P limitation of phytoplankton growth expanded after 2003 and potential Si limitation appeared in 2005 and 2006. Potential P limitation mainly occurred in an area of salinity less than 30 after 2003, while potential Si limitation occurred where the salinity was greater than 30. By comparison with historical data, the concentrations of nitrate and SRP in this upper estuary during November 1980-2006 increased obviously after impoundment of TGD but DRSi decreased. Meanwhile, the ratios of N:P, Si:N and Si:P decreased obviously. PMID:19467558

  9. 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

    Radionuclide activities were measured in sediment cores and suspended particle samples from the Hudson River estuary. Activities of 137Cs, 134Cs, and 60Co, 239240Pu and 238Pu indicate rapid accumulation in marginal cove areas, and very rapid deposition in the harbor adjacent to New York City, resulting in 239240Pu accumulations of more than an order of magnitude greater than the fallout delivery rate. Fallout 239240Pu 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 239240Pu in a saline lake with a high carbonate ion concentration yielded water column activities two orders of magnitude greater 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

  10. Distribution and ecological risk assessment of polycyclic aromatic hydrocarbons in water, suspended particulate matter and sediment from Daliao River estuary and the adjacent area, China.

    Zheng, Binghui; Wang, Liping; Lei, Kun; Nan, Bingxu

    2016-04-01

    Polycyclic aromatic hydrocarbons (PAHs) contamination was investigated in concurrently sampled surface water, suspended particulate matter (SPM) and sediment of Daliao River estuary and the adjacent area, China. The total concentrations of PAHs ranged from 71.12 to 4255.43 ng/L in water, from 1969.95 to 11612.21 ng/L in SPM, and from 374.84 to 11588.85 ng/g dry weight (dw) in sediment. Although the 2-3 ring PAHs were main PAH congeners in water and SPM, the 4-6 ring PAHs were also detected and their distribution was site-specific, indicating a very recent PAHs input around the area since they were hydrophobic. The PAHs pollution was identified as mixed combustion and petroleum sources. Based on species sensitivity distribution (SSD), the ecological risk in SPM from 82% stations was found to be higher obviously than that in water. The risk in water was basically ranked as medium, while the risk in SPM was ranked as high. Analysis with sediment quality guidelines (SQGs) indicated that negative eco-risk occasionally occurred in about 50% stations, while negative eco-risk frequently occurred in about 3% stations only caused by Phenanthrene(Phe) and Dibenzo(a,h)anthracene(DBA). Here freshwater acute effects data together with saltwater data were used for SSD model. And this method could quickly give the rational risk information, and achieved our objective that compared the spatial difference of risk levels among three compartments. The results confirmed that the use of freshwater acute effects data from the ECOTOX database together with saltwater effects data is acceptable for risk assessment purposes in estuary. PMID:26855211

  11. 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

    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 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

  12. Bacteria of fecal origin in mangrove oysters (Crassostrea rhizophorae) in the Coc River estuary, Cear State, Brazil Bactrias de origem fecal contaminantes de ostra Crassostrea rhizophorae, oriundas do esturio do Rio Coc, Estado do Cear, Brasil

    Silva, Ana I. M.; Regine H.S.F. Vieira; Francisca G.R. Menezes; Antonio A. Fonteles-Filho; Regina C. O. Torres; SANT'ANNA Ernani S.

    2004-01-01

    This study was aimed at evaluating the microbiological quality of mangrove oysters (Crassostrea rhizophorae), collected at a natural oyster bed in the estuary of Coc river (Fortaleza, Cear, Brazil). MPN values were used for estimating the total (TC) and fecal (FC) coliforms and Enterococcus spp. TC and FC MPN values in the whole muscle and intervalve liquid ranged from 1,600/g and from