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Sample records for gironde estuary southwest

  1. Turbidity in the fluvial Gironde Estuary (southwest France) based on 10-year continuous monitoring: sensitivity to hydrological conditions

    Science.gov (United States)

    Jalón-Rojas, I.; Schmidt, S.; Sottolichio, A.

    2015-06-01

    Climate change and human activities impact the volume and timing of freshwater input to estuaries. These modifications in fluvial discharges are expected to influence estuarine suspended sediment dynamics, and in particular the turbidity maximum zone (TMZ). Located in southwest France, the Gironde fluvial-estuarine system has an ideal context to address this issue. It is characterized by a very pronounced TMZ, a decrease in mean annual runoff in the last decade, and it is quite unique in having a long-term and high-frequency monitoring of turbidity. The effect of tide and river flow on turbidity in the fluvial estuary is detailed, focusing on dynamics related to changes in hydrological conditions (river floods, periods of low discharge, interannual changes). Turbidity shows hysteresis loops at different timescales: during river floods and over the transitional period between the installation and expulsion of the TMZ. These hysteresis patterns, that reveal the origin of sediment, locally resuspended or transported from the watershed, may be a tool to evaluate the presence of remained mud. Statistics on turbidity data bound the range of river flow that promotes the upstream migration of TMZ in the fluvial stations. Whereas the duration of the low discharge period mainly determines the TMZ persistence, the freshwater volume during high discharge periods explains the TMZ concentration at the following dry period. The evolution of these two hydrological indicators of TMZ persistence and turbidity level since 1960 confirms the effect of discharge decrease on the intensification of the TMZ in tidal rivers; both provide a tool to evaluate future scenarios.

  2. Impact of climate change on Gironde estuary

    International Nuclear Information System (INIS)

    Within the THESEUS European project, a simplified mathematical model for storm surge levels in the Bay of Biscay was adjusted on 10 events at Le Verdon using wind and pressure fields from CLM/SGA, so that the water levels at Le Verdon have the same statistic quantiles as observed tide records for the period [1960-2000]. A numerical model of the Gironde Estuary was used to evaluate future water levels at 6 locations of the estuary from Le Verdon to Bordeaux and to assess the changes in the quantiles of water levels during the 21. century using ONERC's pessimistic scenario for sea level rise (60 cm). The analysis of future storm surge levels shows a decrease in their quantiles at Le Verdon,, whereas there is an increase of the quantiles of total water levels. This increase is smaller than the sea level rise and gets even smaller as one enters farther upstream in the estuary. A series of flood maps for different return periods between 2 and 100 years and for four time periods ([1960-1999], [2010-2039], [2040-2069] and [2070-2099]) have been built for the region of Bordeaux. Quantiles of water levels in the flood plain have also been calculated. The impact of climate change on the evolution of flooded areas in the Gironde Estuary and on quantiles of water levels in the flood plain mainly depends on the sea level rise. Areas which are not currently flooded for low return periods will be inundated in 2100. The influence of river discharges and dike breaching should also be taken into account for more accurate results. (authors)

  3. EVOLUTION OF PARTICULATE CHLOROPHYLL IN THE GIRONDE ESTUARY

    OpenAIRE

    Merle, A.; Cherqaoui, A.; Brzezinski, L.

    1983-01-01

    The spatio-temporal evolution of particulate chlorophyll in suspension in the Gironde estuary has been studied by photo acoustic spectroscopy. Disapearance of fluvial chlorophyll has been observed in the upper part of the estuary ; it has been correlated with the increase in turbidity. Quantitative measurements have been tempted using calibration with algaes cultures of varying turbidity. Chlorophyll again appears near by the sea. Marine chlorophyll has a shifted spectrum relative to the fluv...

  4. Numerical-simulation of the turbidity maximum transport in the gironde estuary (france)

    OpenAIRE

    Li, Zh; Nguyen, Kd; Bruncottan, Jc; Martin, Jm

    1994-01-01

    A coupled two-dimensional vertical width-integrated hydrodynamic and sediment transport numerical model is presented to simulate the ''turbidity maximum'' formation and dynamics in the Gironde estuary. A turbulence closure sub-model is used to parametrize the turbulent mixing process. The numerical results of a five-day simulation are compared with field measurements carried out at several locations. The formation and the displacement of the turbidity maximum during one tidal cycle are correc...

  5. Turbidity in the fluvial Gironde Estuary (S-W France) based on 10 year continuous monitoring: sensitivity to hydrological conditions

    Science.gov (United States)

    Jalón-Rojas, I.; Schmidt, S.; Sottolichio, A.

    2015-03-01

    Climate change and human activities impact the volume and timing of freshwater input to estuaries. These modifications in fluvial discharges are expected to influence estuarine suspended sediment dynamics, and in particular the turbidity maximum zone (TMZ). Located in the southwest France, the Gironde fluvial-estuarine systems has an ideal context to address this issue. It is characterized by a very pronounced TMZ, a decrease in mean annual runoff in the last decade, and it is quite unique in having a long-term and high-frequency monitoring of turbidity. The effect of tide and river flow on turbidity in the fluvial estuary is detailed, focusing on dynamics related to changes in hydrological conditions (river floods, periods of low-water, inter-annual changes). Turbidity shows hysteresis loops at different time scales: during river floods and over the transitional period between the installation and expulsion of the TMZ. These hysteresis patterns, that reveal the origin of sediment, locally resuspended or transported from the watershed, may be a tool to evaluate the presence of remained mud. Statistics on turbidity data bound the range of river flow that promotes the TMZ installation in the fluvial stations. Hydrological indicators of the persistence and turbidity level of the TMZ are also defined. The long-term evolution of these indicators confirms the influence of discharge decrease on the intensification of the TMZ in tidal rivers, and provides a tool to evaluate future scenarios.

  6. Numerical modeling techniques for the study of horizontal ciruclation in estuaries - Apllication to the Gironde

    OpenAIRE

    Unnikrishnan, A.s.

    1985-01-01

    Recent advances in fast computers have helped in developing numerical models for the study of estuarine and coastal dynamics. So far, different workers have made definitions of an estuary mainly based on salinity considerations. For example, following PRITCHARD (1965), an estuary may be defined as "a semi enclosed body of water having a free connection with the open sea within which sea water is mesurably diluted with fresh water derived from land drainage". In the case of european estuaries,...

  7. Tritium study of the mixing of waters in lakes and estuaries, with particular reference to the Lake of Geneva and the Gironde

    International Nuclear Information System (INIS)

    The results presented here relate to a general study of the dynamics of the Lake of Geneva (Leman) and the Gironde. Tritium was used as a tracer in order to differentiate waters with identical physico-chemical characteristics. On the Lake of Geneva campaigns carried out at different hydrological periods on the two main affluents revealed a surface current, a main current at half depth and a turbidity current in a sub-lacustrine canyon. Three layers with their own well-defined dynamic behaviour (0-50 m, 50-150 m and 150-310 m) correspond to these movements. Only the surface layer may become homogeneous in winter. In the Gironde the use of tritium enabled us to determine, in waters having identical or constant salinities, whether the fresh waters were of different fluvial origins. In this way we observed a substantial difference in dynamic behaviour and the absence of any significant exchanges between the edges and the centre of the Gironde. In estuaries this method should permit the study of flood propagation and the formation of high-turbidity zones. (author)

  8. Tritium Study of the Mixing of Waters in Lakes and Estuaries, with Particular Reference to the Lake of Geneva and the Gironde

    International Nuclear Information System (INIS)

    The results presented here relate to a general study of the dynamics of the Lake of Geneva (Léman) and the Gironde. Tritium was used as a tracer in order to differentiate waters with identical physico-chemical characteristics. On the Lake of Geneva campaigns carried out at different hydrological periods on the two main affluents revealed a surface current, a main current at half depth and a turbidity current in a sub- lacustrine canyon. Three layers with their own well-defined dynamic behaviour (0 - 50 m, 50 - 150 m and 150 - 310 m) correspond to these movements. Only the surface layer may become homogeneous in winter. In the Gironde the use of tritium enabled us to determine, in waters having identical or constant salinities, whether the fresh waters were of different fluvial origins. In this way we observed a substantial difference in dynamic behaviour and the absence of any significant exhanges between the edges and the centre of the Gironde. In estuaries this method should permit the study of flood propagation and the formation of high-turbidity zones. (author)

  9. Geochemical risk assessment of a case study of climate change adaptation policy: the managed realignment of an island in the Gironde Estuary (SW France)

    Science.gov (United States)

    Ivanovsky, Anastasia; Coynel, Alexandra; Kessaci, Kahina; Kervella, Stéphane; Curti, Cécile; Sottolichio, Aldo; Blanc, Gérard

    2014-05-01

    During the last millennium, poldering had consisted to reclaim land from the sea by pumping and creating dike to develop, for example, agricultural lands (e.g. tidal marshes, estuarine island). During 1980's, gain land from the sea stopped in Europe because of the concern of rising sea level and for better controlling flood events. This study aims at evaluating the impact of an accidental realignment due to a dam-break on the "Ile Nouvelle" in the Gironde Estuary (France) during the "Xynthia" storm (27-28 February 2010). After this accident, the General Council of Gironde and the national office for coastal territory preservation ("Conservatoire du Littoral"), which own this island, have adopted a new policy of managed realignment allowing soil submersion by estuarine water during each high tide in order to promote rehabilitation of a wetland ecosystem. This management policy has resulted in the re-inundation of formerly agricultural embanked soils. The regular tidal re-inundation of formerly agricultural embanked soils has induced strong biological and morphological changes (mechanical erosion, siltation). Based on 50 soils samples, spatial distribution of priority metal contaminants (Ni, Cr, Zn, Cu, As, Cd, Pb and Hg) was conducted using GIS (Arcview®). Metal concentrations were compared to local geochemical background measured at the bottom of a sediment core in the Gironde Estuary. Only a moderate Cd enrichment was observed (~2 to 7 times) and attributed to former deliberate submersion of vineyard soils on the island to fight off the damage caused by Phylloxera. Leaching experiments simulating episodic immersion during winter (salinity 0) and summer (salinity 12) were performed for investigating metal reactivity during soil suspension. Part of Cu and As were released from the soils at whatever salinity, whereas Cd release occurred only for salinity 12. Such desorption processes present potential geochemical risk to the Gironde Estuary. In contrast, during winter submersion events the studied soils would act as Cd sinks, adsorption being the dominating process. Coupling Acoustic Doppler Current Profiler (ADCP) and 2 multi-parameters probes (OBS and SMATCH) during 2 spring-tide cycles allowed estimating residual metal fluxes, suggesting that under these conditions the Ile Nouvelle acts as a metal sink receiving ~5 kg of Cd, 440 kg of Cu et 480 kg of As. A bathymetry mapping of the corridor (mechanical erosion of the de-poldering area) was used to estimate the annual sedimentary and metals fluxes exported due to its erosion. Annual fluxes related to corridor erosion, compared to fluxes into the Gironde Estuary are significant for Cu and As. With climate change adaptation policies, managed realignment is becoming more common in the future. Consequently, it will be necessary before this management policy to assess the geochemical risk of the re-inundation of formerly embanked soils.

  10. Persistent organic pollutants in a marine bivalve on the Marennes-Oléron Bay and the Gironde Estuary (French Atlantic Coast) - part 1: bioaccumulation.

    Science.gov (United States)

    Luna-Acosta, A; Budzinski, H; Le Menach, K; Thomas-Guyon, H; Bustamante, P

    2015-05-01

    The aim of this study was to determine 1) the relevance of using the Pacific oyster Crassostrea gigas as a sentinel organism, at a juvenile stage, for polycyclic aromatic hydrocarbon (PAH) and persistent organic pollutant (polychlorobiphenyl, PCB, polybromodimethylether, PBDE, and organochlorine pesticide, OCP) contamination, 2) the potential levels of chemical organic contamination in the Marennes-Oléron Bay, and their potential sources and 3) the potential influence of physiological or environmental factors on contaminant body burdens in oysters. To this end, juvenile oysters purchased from an oyster hatchery were transplanted to a reference site, in Bouin, and to different transplantation sites in the Marennes-Oléron Bay, the first oyster production area in France, and in the Gironde Estuary, the biggest estuary in Occidental Europe. Transplantations were done during summer and winter. Whole oyster soft tissues from each site were analysed for PAHs, PCBs, PBDEs and OCPs. Results obtained with a transplantation period of 3months suggest that C. gigas, at the juvenile stage, is a relevant sentinel organism for short-term assessment of contamination for these contaminants. In addition, no significant effects of physiological factors on contaminant body burdens were observed. Principal component analysis revealed two distinct groups of contaminants (PAHs and OPCs, and PCBs and PBDEs) and three groups of sites: 1) the reference site, 2) Les Palles (LP) and Boyard (BOY) in winter and 3) all the other sites. The group of LP and BOY was clearly defined by the levels of PAHs and OCPs, suggesting higher levels of contamination of these chemical compounds on these sites, potentially due to local contamination sources. In addition, no relevant effects of physiological or environmental factors on contaminant body burdens were observed. Results suggest also a predominance of contaminants related to agricultural activities along the Marennes-Oléron Bay, and therefore, further studies on the presence of pesticides in this region should be considered. PMID:25440063

  11. Persistent organic pollutants in a marine bivalve on the Marennes-Oléron Bay and the Gironde Estuary (French Atlantic Coast) - part 2: potential biological effects.

    Science.gov (United States)

    Luna-Acosta, A; Bustamante, P; Budzinski, H; Huet, V; Thomas-Guyon, H

    2015-05-01

    Contaminant effects on defence responses of ecologically and economically important organisms, such as the Pacific oyster Crassostrea gigas, are likely to influence their ability to resist infectious diseases, particularly at the young stages. The aim of this study was to explore the potential relationships between organic contaminants accumulated in the soft tissues of juvenile oysters, defence responses and physiological condition. Oysters were transplanted during summer and winter periods in different sites in the Marennes-Oléron Bay, the first area of oyster production in France, and in the Gironde Estuary, the biggest estuary in Occidental Europe. Amongst the battery of biochemical and physiological biomarkers applied in the present work [superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx), malondyaldehyde (MDA), catecholase, laccase and lysozyme in gills, digestive glands, mantle and haemolymph, glycogen, proteins and lipids in the digestive gland and the condition index at the whole-organism level], MDA and lysozyme in the digestive gland and SOD, GPx and laccase in plasma contributed in order to significantly discriminate the sites in which oysters bioaccumulated different levels of heavy polycyclic aromatic hydrocarbons (HPAHs), polychlorobiphenyls (PCBs), polybromodiphenylethers (PBDEs), dichlorodiphenyltrichloroethanes (DDTs) and lindane. These results strengthen the hypothesis that it is possible to differentiate sites depending on their contamination levels and biological effects by carrying out studies with transplanted juvenile oysters. In addition, correlations were found between antioxidant and immune-defence responses, and PAH and DDT body burdens in the first area of oyster production in France (the Marennes-Oléron Bay) and where considerable oyster mortalities have been reported. This result suggests that the presence of organic chemical contaminants in the Marennes-Oléron Bay may influence defence responses in juveniles of C. gigas, and, therefore, could influence their ability to resist infectious diseases. PMID:25666833

  12. Spatiotemporal variation of dissolved 238U in the Gironde fluvial-estuarine system (France)

    International Nuclear Information System (INIS)

    Dissolved uranium (238UD) was measured within the Gironde fluvial-estuarine system (France), which is well known for its heavy metal pollution and its subsequent environmental effects. Dissolved 238U activities exhibit the highest levels and variability in the small watersheds of the Isle and Riou-Mort rivers, ascribed to low discharges and the occurrence of peculiar features (local U ore deposits; Permian layers). The major tributaries of the Gironde Estuary: Garonne, Lot and Dordogne, show rather stable 238UD, higher than the global mean riverine uranium activity. In the Gironde Estuary 238UD behaves conservatively along the river-estuary-ocean transect. Dissolved 238U distribution in the Gironde fluvial-estuarine system can be explained by the characteristics of considered drainage basins. There is no evidence of anthropogenic pollution

  13. Mixing and flushing time scales in the Azhikode Estuary, southwest coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Revichandran, C.; Pylee, A.

    1998-01-01

    Flushing time scales of the Azhikode Estuary, Kerala, India showed pronounced dry season and wet season signals as well as large inter-annual variation. Cumulative flushing time of the estuary varies from 4.8 tide cycles in April to 1.22 tide cycles...

  14. Formation of anoxia and denitrification in the bottom waters of a tropical estuary, southwest coast of India

    Directory of Open Access Journals (Sweden)

    G. D. Martin

    2010-03-01

    Full Text Available Hydrographic characteristics of the southwest coast of India and its adjoining Cochin backwaters (CBW were studied during the summer monsoon period. Anomalous formation of anoxia and denitrification were observed in the bottom layers of CBW, which have not been previously reported elsewhere in any tropical estuarine systems. The prevalent upwelling in the Arabian Sea (AS brought cool, high saline, oxygen deficient and nutrient-rich waters towards the coastal zone and bottom layers of CBW during the high tide. High freshwater discharge in the surface layers brought high amount of nutrients and makes the CBW system highly productive. Intrusion of AS waters seems to be stronger towards the upstream end (~15 km, than had been previously reported, as a consequence of the lowering of river discharges and deepening of channels in the estuary. Time series measurements in the lower reaches of CBW indicated a low mixing zone with increased stratification, 3 h after the high tide (highest high tide and high variation in vertical mixing during the spring and neap phases. The upwelled waters (O2?40 ?M intruded into the estuary was found to lose more oxygen during the neap phase (suboxic O2?4 ?M than spring phase (hypoxic O2?10 ?M. Increased stratification coupled with low ventilation and presence of high organic matter have resulted in an anoxic condition (O2=0, 2–6 km away from barmouth of the estuary and leads to the formation of hydrogen sulphide. The reduction of nitrate and formation of nitrite within the oxygen deficient waters indicated strong denitrification intensity in the estuary. The expansion of oxygen deficient zone, denitrification and formation of hydrogen sulphide may lead to a destruction of biodiversity and an increase of green house gas emissions from this region.

  15. Transport of dissolved nutrients and chlorophyll a in a tropical estuary, southwest coast of India.

    Digital Repository Service at National Institute of Oceanography (India)

    Lallu, K.R.; Fausia, K.H.; Vinita, J.; Balachandran, K.K.; NaveenKumar, K.R.; Rehitha, T.V.

    2014-01-01

    Intra-tidal variability in the transport of materials through the Cochin estuary was studied over successive spring and neap tides to estimate the export fluxes of nutrients and chlorophyll a into the adjoining coastal zone. The results showed...

  16. Fresh water influence on nutrient stoichiometry in a tropical estuary, Southwest coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Martin, G.D.; Vijay, J.G.; Laluraj, C.M.; Madhu, N.V.; Joseph, T.; Nair, M.; Gupta, G.V.M.; Balachandran, K.K.

    2008-01-01

    pre-monsoon changes the estuary into a vertically mixed, eutrophic and flow-restricted system supporting an enhanced organic production. This implies that monsoon-induced hydrology plays an important role in regulating the nutrients, secondary...

  17. Observed mixed standing-wave signatures in Cochin Estuary on the southwest coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    DineshKumar, P.K.; Srinivas, K.; Muraleedharan, K.R.; Thottam, T.J.

    2009-01-01

    at the mouth of the estuary, located about 45 km upstream, showed very little dissipation had taken place in the tidal amplitudes, implying that tides are amplified because of a physical barrier. The amplitudes of the major tidal constituents O sub(1), K sub(1...

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

    Science.gov (United States)

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

    2014-12-01

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

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

    Digital Repository Service at National Institute of Oceanography (India)

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

    2008-01-01

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

  20. Modeling ecosystem processes with variable freshwater inflow to the Caloosahatchee River Estuary, southwest Florida. II. Nutrient loading, submarine light, and seagrasses

    Science.gov (United States)

    Buzzelli, Christopher; Doering, Peter; Wan, Yongshan; Sun, Detong

    2014-12-01

    Short- and long-term changes in estuarine biogeochemical and biological attributes are consequences of variations in both the magnitude and composition of freshwater inputs. A common conceptualization of estuaries depicts nutrient loading from coastal watersheds as the stressor that promotes algal biomass, decreases submarine light penetration, and degrades seagrass habitats. Freshwater inflow depresses salinity while simultaneously introducing colored dissolved organic matter (color or CDOM) which greatly reduces estuarine light penetration. This is especially true for sub-tropical estuaries. This study applied a model of the Caloosahatchee River Estuary (CRE) in southwest Florida to explore the relationships between freshwater inflow, nutrient loading, submarine light, and seagrass survival. In two independent model series, the loading of dissolved inorganic nitrogen and phosphorus (DIN and DIP) was reduced by 10%, 20%, 30%, and 50% relative to the base model case from 2002 to 2009 (2922 days). While external nutrient loads were reduced by lowering inflow (Q0) in the first series (Q0 series), reductions were accomplished by decreasing the incoming concentrations of DIN and DIP in the second series (NP Series). The model also was used to explore the partitioning of submarine light extinction due to chlorophyll a, CDOM, and turbidity. Results suggested that attempting to control nutrient loading by decreasing freshwater inflow could have minor effects on water column concentrations but greatly influence submarine light and seagrass biomass. This is because of the relative importance of Q0 to salinity and submarine light. In general, light penetration and seagrass biomass decreased with increased inflow and CDOM. Increased chlorophyll a did account for more submarine light extinction in the lower estuary. The model output was used to help identify desirable levels of inflow, nutrient loading, water quality, salinity, and submarine light for seagrass in the lower CRE. These findings provide information essential to the development of a resource-based approach to improve the management of both freshwater inflow and estuarine biotic resources.

  1. On the quantity and composition of floating plastic debris entering and leaving the Tamar Estuary, Southwest England.

    Science.gov (United States)

    Sadri, Saeed S; Thompson, Richard C

    2014-04-15

    The majority of plastic debris found in the marine environment has land based sources and rivers are considered an important medium for transfer of this debris. Here we report on the quantity and composition of floating plastic debris collected from surface waters of the Tamar Estuary. This represents the first study of riverine transport of floating plastic debris into European waters during different tidal regimes. Plastics were found in a variety of forms and sizes and microplastics (<5 mm) comprised 82% of the debris. The most abundant types of plastic were Polyethylene (40%), Polystyrene (25%) and Polypropylene (19%). There was a significant difference in size frequency distribution between the spring and neap tides with more fragments of larger size observed during spring tides. While it is clear that debris has accumulated on shorelines within the estuary, during our study this river did not identify as a net source or sink. PMID:24613232

  2. Fine-scale responses of phytoplankton to freshwater influx in a tropical monsoonal estuary following the onset of southwest monsoon

    Digital Repository Service at National Institute of Oceanography (India)

    Pednekar, S.M.; Matondkar, S.G.P.; Gomes, H.R.; Goes, J.I.; Parab, S.G.; Kerkar, V.

    2011-01-01

    High Pressure Liquid Chro- matography (Agilent circleR 1100 series) where pigment separation was done in a C-18 reverse-phase col- umn using the eluent gradient program of Wright et al (1991) and Parab et al (2006), using DHI, Denmark pigment standards.... Climatol. 28(5) 643– 657. Tomas C R 1997 Identifying Marine Phytoplankton (New York: Academic Press), pp. 858. Vijith V, Sundar D and Shetye S R 2009 Time-dependence of salinity in monsoonal estuaries; Estuarine Coast. Shelf Sci. 85(4) 601–608. Wright SW...

  3. Behaviour of REEs in a tropical estuary and adjacent continental shelf of southwest coast of India: evidence from anomalies

    International Nuclear Information System (INIS)

    The distribution and accumulation of the rare earth elements (REE) in the sediments of the Cochin Estuary and adjacent continental shelf were investigated. The rare earth elements like La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and the heavy metals like Mg, V, Cr, Mn, Fe, Cu, Zn, U, Th were analysed by using standard analytical methods. The Post-Archean Australian Shale composition was used to normalise the rare earth elements. It was found that the sediments were more enriched with the lighter rare earth elements than the heavier ones. The positive correlation between the concentrations of REE, Fe and Mn could explain the precipitation of oxyhydroxides in the study area. The factor analysis and correlation analysis suggest common sources of origin for the REEs. From the Ce-anomalies calculated, it was found that an oxic environment predominates in all stations except the station No. 2. The Eu-anomaly gave an idea that the origin of REEs may be from the feldspar. The parameters like total organic carbon, U/Th ratio, authigenic U, Cu/Zn, V/Cr ratios revealed the oxic environment and thus the depositional behaviour of REEs in the region. (author)

  4. Behaviour of REEs in a tropical estuary and adjacent continental shelf of southwest coast of India: Evidence from anomalies

    Science.gov (United States)

    Deepulal, P. M.; Kumar, T. R. Gireesh; Sujatha, C. H.

    2012-10-01

    The distribution and accumulation of the rare earth elements (REE) in the sediments of the Cochin Estuary and adjacent continental shelf were investigated. The rare earth elements like La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and the heavy metals like Mg, V, Cr, Mn, Fe, Cu, Zn, U, Th were analysed by using standard analytical methods. The Post-Archean Australian Shale composition was used to normalise the rare earth elements. It was found that the sediments were more enriched with the lighter rare earth elements than the heavier ones. The positive correlation between the concentrations of REE, Fe and Mn could explain the precipitation of oxyhydroxides in the study area. The factor analysis and correlation analysis suggest common sources of origin for the REEs. From the Ce-anomalies calculated, it was found that an oxic environment predominates in all stations except the station No. 2. The Eu-anomaly gave an idea that the origin of REEs may be from the feldspar. The parameters like total organic carbon, U/Th ratio, authigenic U, Cu/Zn, V/Cr ratios revealed the oxic environment and thus the depositional behaviour of REEs in the region.

  5. Tidal bore dynamics in funnel-shaped estuaries

    Science.gov (United States)

    Bonneton, P.; Bonneton, N.; Parisot, J.-P.; Castelle, B.

    2015-02-01

    The formation and dynamics of tidal bores in funnel-shaped estuaries is investigated from both a global tidal wave scaling analysis and new quantitative field observations. We show that tidal bore occurrence in convergent estuaries can be estimated from a dimensionless scaling parameter characterizing the relative intensity of nonlinear friction versus local inertia in the momentum equation. A detailed analysis of tidal bore formation and secondary wave structure is presented from a unique long-term database (observations of more than 200 tides) acquired during four campaigns in the two main French tidal-bore estuaries: the Seine and Gironde/Garonne estuaries. We describe the effect of freshwater discharge on the global tidal wave transformation at the estuarine scale and on local tidal bore occurrence in the upper estuary. Our field data suggest that the tidal bore intensity is mainly governed by the dimensionless tidal range, which characterizes the local tidal wave nonlinearity. We also show that the secondary wavefield associated with tidal bore propagating in natural estuaries differs significantly from those associated to undular bores in rectangular channels. In particular, we observe an abrupt decrease of the whelp steepness when the Froude number goes below 1.1. This secondary field transition can explain why tidal bore occurrence in worldwide estuaries is certainly underestimated.

  6. Estuary Live!

    Science.gov (United States)

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

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

    International Nuclear Information System (INIS)

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

  8. Southwest Economy

    Science.gov (United States)

    The Dallas Federal Reserve Bank publishes Southwest Economy bimonthly; it covers "agriculture, banking, energy, high technology, manufacturing and international trade" in the Texas- New Mexico- Louisiana region.

  9. Estuary Live!!!

    Science.gov (United States)

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

  10. Currents in the Cochin estuarine system [southwest coast of India] during March

    Digital Repository Service at National Institute of Oceanography (India)

    Srinivas, K.; Revichandran, C.; Thottam, T.J.; Maheswaran, P.A.; Asharaf, T.T.M.; Murukesh, N.

    2003-01-01

    Analysis of current meter data collected in the Cochin estuarine system (southwest coast of India) has been made, to understand variations of currents in the estuary for spring and neap tidal phases during March 2000. The currents were strongest...

  11. Factors controlling the temporal and spatial variations in Synechococcus abundance in a monsoonal estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Rajaneesh, K.M.; Mitbavkar, S.

    2013-01-01

    Temporal and spatial variations in Synechococcus abundance were investigated over an annual cycle (February`10–January`11) along a salinity gradient (0–35) in the tropical Zuari estuary, influenced by south-west monsoons. Synechococcus exhibited...

  12. Estuary regime

    International Nuclear Information System (INIS)

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

  13. Biogeochemistry of Estuaries

    Science.gov (United States)

    Burdige, David J.

    2007-12-01

    Whether you are interested in material flux from the continents to the oceans or whether the oysters set down in front of you at a waterfront restaurant may have come from polluted waters, we know estuaries are important places. However, anyone attempting to summarize and synthesize the long and rich literature of estuarine research is presented with a daunting task. This is because beyond the concept of an estuary being the transition zone where ``fresh water meets seawater,'' the exact definition of an estuary is not uniformly agreed upon by scientists in this field. Also, estuaries-regardless of how they are defined-tend to be highly heterogeneous, in both space and time. Against this backdrop, Thomas Bianchi's Biogeochemistry of Estuaries successfully tackles its subject matter and is an exciting addition to the field of estuarine research.

  14. Estuary Classification Revisited

    CERN Document Server

    Guha, Anirban

    2012-01-01

    The governing equations of a tidally averaged, width averaged, rectangular estuary has been investigated. It's theoretically shown that the dynamics of an estuary is entirely controlled by three parameters: (i) the Estuarine Froude number, (ii) the Tidal Froude number and (iii) the Estuarine Aspect ratio. The momentum, salinity and integral salt balance equations can be completely expressed in terms of these control variables. The estuary classification problem has also been reinvestigated. It's found that these three control variables can completely specify the estuary type. Comparison with real estuary data shows very good match. Additionally, we show that the well accepted leading order estuarine integral salt balance equation is inconsitent with the leading order salinity equation in an order of magnitude sense.

  15. Variation patterns in individual fish responses to chemical stress among estuaries, seasons and genders: the case of the European flounder (Platichthys flesus) in the Bay of Biscay.

    Science.gov (United States)

    Laroche, Jean; Gauthier, Olivier; Quiniou, Louis; Devaux, Alain; Bony, Sylvie; Evrard, Estérine; Cachot, Jérôme; Chérel, Yan; Larcher, Thibaut; Riso, Ricardo; Pichereau, Vianney; Devier, Marie Hélène; Budzinski, Hélène

    2013-02-01

    The objective was to describe and model variation patterns in individual fish responses to contaminants among estuaries, season and gender. Two hundred twenty-seven adult European flounders were collected in two seasons (winter and summer) in four estuaries along the Bay of Biscay (South West France), focusing on a pristine system (the Ster), vs. three estuaries displaying contrasted levels of contaminants (the Vilaine, Loire and Gironde). Twenty-three variables were measured by fish, considering the load of contaminants (liver metals, liver and muscle persistent organic pollutants, muscle polycyclic aromatic hydrocarbons); the gene expression (Cyt C oxydase, ATPase, BHMT, Cyt P450 1A1, ferritin); the blood genotoxicity (Comet test); and liver histology (foci of cellular alteration-tumour, steatosis, inflammation, abnormal glycogen storage). Canonical redundancy analysis (RDA) was used to model these variables using gender, season and estuary of origin as explanatory variables. The results underlined the homogeneity of fish responses within the pristine site (Ster) and more important seasonal variability within the three contaminated systems. The complete model RDA was significant and explained 35 % of total variance. Estuary and season respectively explained 30 and 5 % of the total independent variation components, whilst gender was not a significant factor. The first axis of the RDA explains nearly 27 % of the total variance and mostly represents a gradient of contamination. The links between the load of contaminants, the expression of several genes and the biomarkers were analysed considering different levels of chemical stress and a possible multi-stress, particularly in the Vilaine estuary. PMID:23138562

  16. Phytoplankton spring bloom of the Gironde plume waters in the Bay of Biscay: early phosphorus limitation and food-web consequences

    OpenAIRE

    Herbland, Alain; Delmas, Daniel; Laborde, Pierre; Sautour, Benoit; Artigas, Felipe

    1998-01-01

    Au cours du printemps 1995 (2¿25 mai), une campagne océanographique a été réalisée à bord du NO Poséidon (Allemagne) sur le plateau continental Sud-Gascogne. L'objectif était l'étude de la structure et du fonctionnement du réseau trophique planctonique des eaux issues de l'estuaire de la Gironde. Les concentrations en phosphate dans ces eaux étaient extrêmement faibles (indécelable à moins de 0,1 ?mol·L?1) tandis que celles du nitrate, du silicate et de l'ammoniaque étaient beaucou...

  17. Modélisation du transport de sédiments mixtes sable-vase et application à la morphodynamique de l'estuaire de la Gironde (France)

    OpenAIRE

    Do, Lan Anh

    2012-01-01

    Cette étude tente de modéliser les taux de transport de sédiments et l'évolution du lit dans un milieu estuarien complexe : l'estuaire de la Gironde, caractérisé par une grande hétérogénéité dans la composition des sédiments de lit, avec la présence de sédiments cohésifs et non-cohésifs ainsi que des mélanges sablo-vaseux. Notre objectif principal est d'étendre un modèle morphodynamique 2D développé par Huybrechts et al. (2012b) pour les sédiments non-cohésifs, afin de ...

  18. Restore America's Estuaries

    Science.gov (United States)

    This non-profit organization promotes the restoration and protection of America's estuaries. Projects encompass scientific research, education and community-based action, including restoration by school youngsters, as well as policy initiatives at the national level. An introduction to estuaries contains concise definitions, value in ecology and economics, current threats, and elements of restoration. Also offers: links to educational resources; news and photo gallery; a CD-rom guide to estuarine restoration.

  19. NEPmap (National Estuary Program Mapper)

    U.S. Environmental Protection Agency — The NEPmap is designed to provide information in context with National Estuary Program Study Areas. There are 28 National Estuary Programs (NEPs) in the U.S.that...

  20. Geochemical, multi-isotopic and hydrogeological characterization of mineralized groundwaters, Entre-deux-Mers area, Gironde (SW France).

    OpenAIRE

    Malcuit, Eline; Ne?grel, Philippe; Petelet Giraud, Emmanuelle; Atteia, O.; Franceschi, M.; Dupuy, A.; Larroque, F.; Schmidt, S.; Marchet, Pierre

    2010-01-01

    Groundwater quality sustainability In the south-west of France, the Eocene aquifer is one of the main resources for irrigation, thermo-mineral water, and mainly for drinking water in the Bordeaux region. This aquifer is characterized by the presence of a large mineralized area, centered on the Entre-deux-Mers region, between the Garonne and the Dordogne rivers, where the groundwaters show strong mineralization and anomalous levels of critical elements, such as sulphates and fluoride, leading ...

  1. Biogeochemical budgets for Tapi Estuary

    Digital Repository Service at National Institute of Oceanography (India)

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

    2004-01-01

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

  2. Go Southwest, Old Man

    OpenAIRE

    Materassi, Mario

    2009-01-01

    Go Southwest, Old Man, a sort of personal remake of 'Go West, Young Man', the founding episteme of the American nineteenth century, conciliates these two souls (well, not to be pretentious, let's simply say two sides) that have actually always lived in harmony. This is a book generated by a quarter of a century spent wandering around the canyons and deserts of Arizona, Colorado, Utah and, above all New Mexico, with a view to penetrating the by now universal legend of the West, approaching the...

  3. The Mandovi and Zuari estuaries

    Digital Repository Service at National Institute of Oceanography (India)

    Shetye, S.R.; DileepKumar, M.; Shankar, D.

    2007-01-01

    . (1994) Species composition and abundance of tintinnids and copepods in the Pichavaram mangroves (South India); Ciencias Marinas 20 371–391. Goswami S. C. (1983) Coexistence and succession of copepod species in the Mandovi and Zuari estuaries, Goa...

  4. FLORA OF MOLOCHNYI ESTUARY COASTS

    Directory of Open Access Journals (Sweden)

    Kolomiychuk V.P.

    2013-09-01

    Full Text Available Present-day characteristic of the coastal flora of Molochnyi eastury is given, that is one of the largest estuaries in Ukraine, the shores and waters of which in 2009 became a part of the Pryazov’ya National Nature Park. The analysis of the main parameters of the flora is made. Rare component of the estuary coastal flora is characterized, further steps to conserve the nature of Pryazov’ya are proposed.

  5. Southwest Journal of Cultures

    Science.gov (United States)

    Sponsored by Northeastern State University in Oklahoma, the Southwest Journal of Cultures is an online scholarly book review venue that is intended to bring academics and others book reviews from the field of culture studies. The Journal was first published in September 2008, and its editors have managed to cover a broad range of topics in a short time. Visitors can scroll through the most recent reviews, some of which include critical appraisals of works like "Chinese Street Opera in Singapore" and "Spare Time in Texas: Recreation and History in the Lone Star State". Visitors are welcome to leave their own comments on each review, and they can also look through the online archive. Those interested in starting their own like-minded project would do well to spend sometime navigating this well-thought out site.

  6. Estuaries and Clean Water Act of 2000

    Science.gov (United States)

    The Office of Water at the Environmental Protection Agency has posted online this document on the new Estuaries and Clean Water Act of 2000. Available in .pdf format, the document summarizes the Act, which emphasizes restoration of estuary habitat.

  7. Estuaries: Where Rivers Meet the Sea

    Science.gov (United States)

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

  8. Natural restoration of a Spanish estuary affected by anthropogenic inputs of NORM

    International Nuclear Information System (INIS)

    The Huelva estuary, located in the southwest of Spain, has been historically affected by waste releases from several factories located in its surroundings and devoted to the production of phosphoric acid and phosphate fertilizers. These wastes, clearly enriched in radionuclides belonging to the uranium series, were stored in open air piles or directly released to the Odiel River. The clear radioactive impact that they have produced in several compartments of the estuary is quite well documented. Fortunately, the waste policy of these factories changed drastically in 1998. Since then, all the wastes are stored in well-protected piles with no interaction with the surrounding environment as before. This means that the input of natural radionuclides from the factories to the estuary has ceased. For that reason, a new time-evolution of the activity concentration of natural radionuclides in these estuarine compartments is expected. In order to analyse the temporal evolution of the contamination in the estuary by natural radionuclides from the interruption time of the releases until the present, the activity concentrations of some natural radionuclides (226Ra, U isotopes, 210Po, 210Pb) in water and sediment samples collected in three different campaigns (1999, 2001 and 2002) have been determined. These results, as well as the activity ratios, are presented in this paper and compared with those determined before 1998, when the releases still oned before 1998, when the releases still occurred. The observed trend shows clearly that the contamination of the estuary by natural radionuclides is decreasing since the change in waste policy, and that the radioactive levels in the waters and sediments are approaching the natural background values of the zone. Consequently, in a few years, a total natural decontamination in natural radionuclides of the Huelva estuary can be expected. (author)

  9. Oil spill trajectory analysis for the Calcasieu Estuary

    International Nuclear Information System (INIS)

    A three-dimensional hydrodynamic model (H3D) was used to determine how oil spills might travel and spread within the Calcasieu River Estuary which has heavy oil traffic. The Calcasieu River is located in the southwest corner of the State of Louisiana and houses valuable wetlands that provide both commercial and recreational fishing and wildlife value to the area. These wetlands also filter water and protect Louisiana's coast areas from hurricane storm surges. An oil spill would damage areas of marshes that would have devastating effects on the entire ecological system within the estuary. A Trajectory Analysis Planner (TAP) H3D computer model is under development by the Hazardous Materials Response Division of the National Oceanic and Atmospheric Administration (NOAA). TAP is a statistical planning tool that randomly samples historical hydrodynamic, hydrology and climatological data, to build up a database with biological and cleanup resource information. TAP can be used to predict which sites within the estuarine system will be most susceptible to oil spills of varying magnitudes, materials and locations. TAP can also estimate the time available for mitigation and remedial actions before the spill can impact the site. Hydrodynamics in the Calcasieu estuary is a combination of processes such as saltwater intrusion and response to water level fluctuations at an open boundary, as well as lake dynamics. H3D provides the three components of velocity, plus scalar quantitiesonents of velocity, plus scalar quantities such as water levels, temperature and salinity distribution on a Cartesian three-dimensional grid. TAP was tested for spills of kerosene, non-weathering oil, crude oil, and gasoline and was able to perform reliable spill trajectory analysis. 12 refs., 9 figs

  10. Towards predicting wading bird densities from predicted prey densities in a post-barrage Severn estuary

    International Nuclear Information System (INIS)

    A winter survey of seven species of wading birds in six estuaries in south-west England was made to develop a method for predicting bird densities should a tidal power barrage be built on the Severn estuary. Within most estuaries, bird densities correlated with the densities of widely taken prey species. A barrage would substantially reduce the area of intertidal flats available at low water for the birds to feed but the invertebrate density could increase in the generally more benign post-barrage environmental conditions. Wader densities would have to increase approximately twofold to allow the same overall numbers of birds to remain post-barrage as occur on the Severn at present. Provisional estimates are given of the increases in prey density required to allow bird densities to increase by this amount. With the exception of the prey of dunlin, these fall well within the ranges of densities found in other estuaries, and so could in principle be attained in the post-barrage Severn. An attempt was made to derive equations with which to predict post-barrage densities of invertebrates from easily measured, static environmental variables. The fact that a site was in the Severn had a significant additional effect on invertebrate density in seven cases. This suggests that there is a special feature of the Severn, probably one associated with its highly dynamic nature. This factor must be identified if the post-barrage densities of invertebrates are to be successful predictinvertebrates are to be successful predicted. (author)

  11. Food Webs in an Estuary.

    Science.gov (United States)

    Dunne, Barbara B.

    The Maryland Marine Science Education Project has produced a series of mini-units in marine science education for the junior high/middle school classroom. This unit focuses on food chains in an estuary. Although the unit specifically treats the Chesapeake Bay, it may be adapted for use with similar estuarine systems. In addition, the unit may be…

  12. 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...

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

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

  14. 75 FR 34975 - Notice of Estuary Habitat Restoration Council's Intent to Revise its Estuary Habitat Restoration...

    Science.gov (United States)

    2010-06-21

    ...Estuary Habitat Restoration Strategy, NOAA Fisheries Service...Estuary Habitat Restoration Strategy comments from [insert name...Do not submit Confidential Business Information or otherwise sensitive...information. A copy of the strategy and other documents...

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

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

  16. ANALYSE DE LA TENDANCE DE L’ABONDANCE DE L’ALOSE ALOSA ALOSA EN GIRONDE À PARTIR DE L’ESTIMATION D’INDICATEURS HALIEUTIQUES SUR LA PÉRIODE 1977-1998.

    Directory of Open Access Journals (Sweden)

    CASTELNAUD G.

    2001-07-01

    Full Text Available Au cours des deux dernières décennies, la population d’alose vraie Alosa alosa a été considérée par différents auteurs en diminution, même vouée à la disparition, puis en progression, ou se maintenant à un haut niveau d’effectif dans le bassin de la Garonne. L’objectif de ce travail est de produire les indicateurs halieutiques les plus aptes à rendre compte de la tendance de l’abondance de l’alose vraie en Gironde sur la période 1977-1998. Ces indicateurs saisonniers sont d’une part la CPUE et d’autre part la production totale et l’effort total qui doivent permettre d’expliciter et de conforter le diagnostic sur la tendance de l’abondance. L’échantillon non-aléatoire de données de capture et d’effort provenant d’un réseau de pêcheurs coopératifs, a été stratifié selon les métiers de pêche, les zones de pêche et les quinzaines de pêche. L’estimation des captures totales et des efforts totaux fait appel à la théorie classique de l’échantillonnage avec stratification. Afin d’obtenir un indice qui reflète le mieux possible les variations d’abondance inter-annuelles et qui limite l’incidence des variations de capturabilité dans l’espace et dans le temps, nous avons utilisé la théorie du Modèle Linéaire Général pour construire un modèle log-linéaire qui donne le même poids aux zones et aux quinzaines de pêche sur toute la période d’étude. Le modèle explique la CPUE comme l’addition des effets principaux des facteurs zone, année et quinzaine. Une évolution en paliers des indices d’abondance est testée grâce à un modèle à erreur auto-régressive. On constate que les paliers sont très hautement significatifs pour la Gironde et les trois compartiments Estuaire, Garonne, Dordogne. L’analyse des trois indicateurs halieutique et la confrontation de leur évolution nous amènent à conclure que l’abondance d’A. alosa est au minimum stable en Gironde et qu’elle a très certainement augmenté au cours de la période 1977-1998. Le saut des indices d’abondance observé en 1994 peut être rapporté à l’effet de la mise en place des passes et ascenseurs à poissons sur les parties amont de Garonne et Dordogne. Ces résultats encourageants ne doivent pas dissuader les gestionnaires d’adopter une approche prudente de la population d’alose dans le bassin de la Garonne, compte tenu du statut de cette espèce en Europe.

  17. Environmental data management in the Sado Estuary

    OpenAIRE

    Caeiro, Sandra Sofia Ferreira Da Silva

    2004-01-01

    Estuaries are perhaps the most threatened environments in the coastal fringe; the coincidence of high natural value and attractiveness for human use has led to conflicts between conservation and development. These conflicts occur in the Sado Estuary since its location is near the industrialised zone of Peninsula of Setúbal and at the same time, a great part of the Estuary is classified as a Natural Reserve due to its high biodiversity. These facts led us to the need of implementing a model o...

  18. Sea level variability in South African estuaries

    Scientific Electronic Library Online (English)

    Eckart H., Schumann.

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

  19. VARIABILITES MORPHOLOGIQUE ET DU TAUX D’HORMONE DE CROISSANCE DES CIVELLES D'ANGUILLES EUROPEENNES (Anguilla anguilla DANS L'ESTUAIRE DE LA GIRONDE AU COURS DE LA SAISON 1997-1998

    Directory of Open Access Journals (Sweden)

    LAMBERT P.

    2003-07-01

    Full Text Available L’objectif de ce travail est de compléter la caractérisation morphologique des civelles entrant dans l’estuaire de la Gironde par un paramètre physiologique, le taux d’hormone de croissance. Le flux d’arrivée a été suivi lors de la saison 1997 – 1998. 303 civelles au stade Vb ont été capturées et analysées individuellement. La longueur et la masse des individus diminuent en février, le facteur de condition seulement en mars. Le taux moyen d’hormone de croissance passe de 6 ng/hypophyse en moyenne en décembre à 16 ng/hypophyse en février et mars pour atteindre 20 ng/hypophyse en avril et mai. L’hypothèse la plus plausible est que cette augmentation du taux d’hormone traduise une détresse physiologique de plus en plus importante des animaux qui arrivent.

  20. Tidal Asymmetry in Amazon Estuary

    Science.gov (United States)

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

    2007-05-01

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

  1. Indian estuaries: Dynamics, ecosystems, and threats

    Digital Repository Service at National Institute of Oceanography (India)

    Shetye, S.R.

    2011-01-01

    runoff lead to striking temporal changes in salinity and velocity fields in these estuaries. A number of habitats that have adapted to such changes are found in the estuaries. The climate change will have an adverse impact on the habitats. So will local...

  2. AFS Estuaries Section - A Successful Partnership

    Science.gov (United States)

    The Estuaries Section of the American Fisheries Society offers travel awards to students in support of their attendance and presentations at the AFS meeting. Since 2007, the Southern Association of Marine Laboratories has partnered with the Estuaries Section to sponsor two stude...

  3. NEW HAMPSHIRE ESTUARIES PROJECT MANAGEMENT PLAN

    Science.gov (United States)

    This Comprehensive Conservation and Management Plan of the New Hampshire Estuaries Project presents a broad framework and specific list of actions to protect and enhance the environmental quality of the estuaries of the State of New Hampshire. It is intended to be a guide for all...

  4. NEW HAMPSHIRE ESTUARIES PROJECT MANAGEMENT PLAN, 2000

    Science.gov (United States)

    The Comprehensive Conservation and Management Plan of the New Hampshire Estuaries Project presents a broad framework and specific list of actions to protect and enhance the environmental quality of the estuaries of the State of New Hampshire. It is intended to be a guide for all ...

  5. SEMINATURAL SILVICULTURE IN SOUTHWEST GERMANY

    Directory of Open Access Journals (Sweden)

    Peter Spathelf

    2009-10-01

    Full Text Available A brief historical overview shows the mainstream development pattern in German silviculture and outlines the adjacent role of seminatural (naturally-oriented silviculture. The rationale for seminatural silviculture is discussed with reference to its ecological and economical aspects. Elements of seminatural silviculture of the Baden-Württemberg-concept are introduced. This concept is not purely a preservation strategy, but recognizes the importance of timber production. Some aspects of selection forest, which is a special case of uneven-aged forest with a long tradition in Southwest Germany, are discussed. As there are still a lot of even-aged (pure forests in Southwest Germany, transformation strategies towards uneven-aged mixed forests are shown with the aid of some examples. Criteria and indicators for seminatural silviculture which have to be developed on a regional or local scale, can be used as a basis for establishing a certification process for Southwest German forests. Seminatural silviculture is suited as a rational and  intergrating  silvicultural     system      to     fulfill     future     requirements     on     forests     in    a    dynamically changing world.

  6. Scouting contaminated estuaries: heavy metal resistant and plant growth promoting rhizobacteria in the native metal rhizoaccumulator Spartina maritima.

    Science.gov (United States)

    Mesa, J; Mateos-Naranjo, E; Caviedes, M A; Redondo-Gómez, S; Pajuelo, E; Rodríguez-Llorente, I D

    2015-01-15

    Spartina maritima is a native endangered heavy metal rhizoaccumulator cordgrass naturally growing in southwest coasts of Spain, where is used as a biotool to rehabilitate degraded salt marshes. Fifteen bacterial strains were isolated from the rhizosphere of S. maritima growing in the estuary of the Tinto River, one of the most polluted areas in the world. A high proportion of bacteria were resistant towards several heavy metals. They also exhibited multiple plant growth promoting (PGP) properties, in the absence and the presence of Cu. Bacillus methylotrophicus SMT38, Bacillusaryabhattai SMT48, B. aryabhattai SMT50 and Bacilluslicheniformis SMT51 were selected as the best performing strains. In a gnobiotic assay, inoculation of Medicago sativa seeds with the selected isolates induced higher root elongation. The inoculation of S. maritima with these indigenous metal-resistant PGP rhizobacteria could be an efficient method to increase plant adaptation and growth in contaminated estuaries during restoration programs. PMID:25467875

  7. 75 FR 61790 - Capital Southwest Corporation; Notice of Application

    Science.gov (United States)

    2010-10-06

    ...companies. In addition, Capital Southwest will comply...Exchange Act.\\6\\ Capital Southwest thus concludes...appropriately reflected in the market value of Capital Southwest's shares...independence and other corporate governance matters, and...

  8. Water Column Methylation in Estuaries

    Science.gov (United States)

    Schartup, A. T.; Calder, R.; Soerensen, A. L.; Mason, R. P.; Balcom, P. H.; Sunderland, E. M.

    2014-12-01

    Methylmercury (MeHg) is a neurotoxin that bioaccumulates in aquatic food webs and affects humans and wildlife through fish consumption. Many studies have measured active methylation/demethylation in ocean margin sediments but few have reported similar rates for the marine water column. This presentation will review available evidence for water column methylation in estuaries, including new experimental measurements of methylation/demethylation rates from a deep subarctic fjord in Labrador Canada collected in Spring and Fall of 2012-2013. We used these and other data to construct a mass budget for MeHg in the estuary and show that water column methylation (with rates ranging from 1.5 to 2.8 % day-1), is the largest contributor, followed by inputs from rivers (4.9 mol year-1), to the in situ pool of MeHg available for uptake by biota. By contrast, the sediment in this system is a net sink for MeHg (-1.5 mol year-1). We discuss the relationship between observed MeHg and other ancillary environmental factors (organic carbon, sulfur and nutrients) as well as implications for the response time of fish to future changes in mercury inputs.

  9. Redissolution of 226Ra from sediments in a Spanish estuary affected by the phosphate industry: model comparisons in the framework of the IAEA EMRAS project

    International Nuclear Information System (INIS)

    The Huelva estuary (south-west Spain), a fully mixed tidal estuary, consists of two rivers: Odiel and Tinto. A phosphate fertilizer processing complex has been releasing NORM radionuclides directly into the Odiel river over several decades. As a consequence, high levels of 226Ra, U and Th isotopes and other radionuclides have been measured in water, suspended matter and bed sediments of the estuary. Nevertheless, direct releases stopped in 1998 due to new regulations from the EU and, since then, a self cleaning process has been observed. It consists of a continuous decrease in activity concentrations in water and bed sediments. The study by means of numerical models of the 226Ra self cleaning process observed in the estuary has been proposed as an EMRAS project task. A model has been proposed by each institute participating in the exercise. Models have different configurations and temporal and spatial resolutions. Some processes, for instance tides or uptake/release of radionuclides between water and sediments, are described in different ways. However, all are started from the same initial conditions, provided by the University of Seville model. The endpoint of the simulations is to give the temporal evolution of the total 226Ra inventory in the bed sediments of the estuary and to estimate from it the sediment halving time. A brief description of the main features of each model is provided and the results are compared and analysed. (authe results are compared and analysed. (author)

  10. Southwest Florida Water Management District

    Science.gov (United States)

    The mission of the Southwest Florida Water Management District is to manage the water and water-related resources within its boundaries. Central to the mission is maintaining the balance between the water needs of current and future users while protecting and maintaining the natural systems that provide the District with its existing and future water supply. The website includes an Information and Education page, which offers activities, newsletters, virtual field trips, and other resources for K-12 students and teachers. Also provided on the site are various datasets, brochures, publications, reports, textual references and links.

  11. Entry strategy of Southwest Airlines

    OpenAIRE

    Cobb, Jonathan; Metzger, Nico; Lawford, Steve

    2009-01-01

    The aim of this project is to understand the main determinants of Southwest Airline's presence on U.S. domestic routes, over the period 2002 to 2007. A new dataset has been constructed, using quarterly and annual data from the U.S. Department of Transportation (DB1B and T100 Origin and Destination databases), and a number of socio-economic and geographic (regional) variables. A range of discrete choice (probit and logit) models have been built and estimated, both for individual quarters, and ...

  12. Assessing the susceptibility of two UK estuaries to nutrient enrichment

    Science.gov (United States)

    Kadiri, Margaret; Bockelmann-Evans, Bettina; Rauen, William B.

    2014-10-01

    The susceptibility of two UK estuaries, the Severn and Solva Estuaries to the risks and impacts of nutrient enrichment was investigated in this study by examining nutrients, dissolved oxygen (DO) and turbidity concentrations in the estuaries and applying a risk assessment model based on the UK's Comprehensive Studies Task Team (CSTT) modelling approach. Both estuaries were found to be nutrient enriched. However, there was no evidence of oxygen depletion in the Severn and algal blooms were not observed due to high turbidity, strong tidal currents and tidally induced vertical mixing conditions in the estuary. Although algal blooms were observed in the Solva Estuary, the estuary was well-oxygenated due to the relatively high water exchange rate and consistent rapid flushing in the estuary. The conditions in the Solva Estuary were predicted to be favourable for phytoplankton productivity and the wider potential implications for future water quality protection strategies in the Solva were discussed.

  13. Estimating bankfull discharge and depth in ungauged estuaries

    Science.gov (United States)

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

    2015-04-01

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

  14. National Estuary Program Study Area Boundaries

    U.S. Environmental Protection Agency — There are 28 National Estuary Programs (NEPs) in the U.S.that implement habitat protection and restoration projects with their partners. This work takes place...

  15. Mercury in sediments of Ulhas estuary

    Digital Repository Service at National Institute of Oceanography (India)

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

    2003-01-01

    Hg levels in water, suspended particulate matter and sediment of the Ulhas estuary are under considerable environmental stress due to the indiscriminate release of effluents from a variety of industries including chlor-alkali plants. Concentration...

  16. Smoking rates low in southwest

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2014-04-01

    Full Text Available No abstract available. Article truncated at 150 words. The Gallup survey confirms that smoking rates in the US are declining and that smoking rates are lower in the Southwest than the US as a whole (1. Nationally, the smoking rate fell to 19.7% in 2013 from 21.1% in 2008. Among the Southwest states California ranked second (15.0%, Colorado ninth (17.4%, and Arizona tenth (17.5%. Only New Mexico was above the Nation's average at 20.0%. Utah remains the state with the lowest percentage of smokers, 12.2 percent, and Kentucky the highest, 30.2 percent. Nine of the 10 states with the lowest smoking rates have outright bans on smoking in private worksites, restaurants, and bars, with California allowing for ventilated rooms. Bans are significantly less common in the 10 states with the highest smoking rates. Kentucky, West Virginia, and Mississippi -- the states with the three highest smoking rates -- do not have statewide smoking bans. In addition, these three ...

  17. Bacterioplankton dynamics in the Mondego estuary (Portugal)

    OpenAIRE

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

    2003-01-01

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

  18. Recovery of an estuary in the southwest coast of India from tsunami impacts

    Digital Repository Service at National Institute of Oceanography (India)

    Laluraj, C.M.; Kesavadas, V.; Balachandran, K.K.; Gerson, V.J.; Martin, G.D.; Shaiju, P.; Revichandran, C.; Joseph, T.; Nair, M.

    2007-01-01

    , Indonesia was among the deadliest disasters in modern history. This tsunami devastated the shores of Indonesia and several Southeast Asian countries including India. A significant enrichment in nutrients in the coastal waters of Dakshin Kannada (west coast...

  19. Estuaries, sediments and shorebirds 1: determinants of the intertidal sediments of estuaries

    International Nuclear Information System (INIS)

    Tidal energy barrages could affect estuarine ecosystems to varying degrees. Of particular concern are the possible effects that such schemes might have on the dozen or so shorebird species that use British estuaries in large numbers on passage, in autumn and spring, and during the winter. The objectives of the research described in this report were to survey the intertidal sediment composition of a sample of contrasting British estuaries; quantify variables measuring the estuary size, shape, shore width and tidal range, together with position and exposure to gales of individual areas within each estuary; to develop equations which relate the sediment composition of an entire estuary, and areas within it, to these variables. (author)

  20. Southwest Washington Coastal Erosion Study

    Science.gov (United States)

    The Columbia River is experiencing a far too common problem of disastrous coastal erosion that has been causing grave concern in its community. Because of this, the US Geological Survey Coastal and Marine Geology Program and the Washington Department of Ecology created the Southwest Washington Coastal Erosion Study to predict management scale coastal change, and provide "coastal communities with decision support tools for integrating scientific research with coastal decision making and long-term land use planning efforts." Visitors can discover the study's approach, findings, and participants. The lengthy, informative research link provides information about the study's five key components: coastal change, sediment budget, coastal processes, predictive modeling, and management support. The authors are currently compiling the data collected. Presently, researchers can find data about the beach profiles and the shorelines. The website offers a great, thorough glossary to assist users with unfamiliar terminology. This site is also reviewed in the June 11, 2004 _NSDL Physical Sciences Report_.

  1. 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...

  2. Salt intrusion study in Cochin estuary - Using empirical models

    Digital Repository Service at National Institute of Oceanography (India)

    Jacob, B.; Revichandran, C.; NaveenKumar, K.R.

    2013-01-01

    that the Cochin estuary experiences a transition from partially or well mixed estuary during post and pre monsoon to a strongly stratified estuary during the monsoon season. Instead of undergoing the entire process of data collection of all the parameters, for a...

  3. Environmental flow assessments for transformed estuaries

    Science.gov (United States)

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

    2015-01-01

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

  4. Prediction in ungauged estuaries: An integrated theory

    Science.gov (United States)

    Savenije, Hubert H. G.

    2015-04-01

    Many estuaries in the world are ungauged. The International Association of Hydrological Sciences completed its science decade on Prediction in Ungauged Basins (PUB) in 2012 (Hrachowitz et al.). Prediction on the basis of limited data is a challenge in hydrology, but not less so in estuaries, where data on fundamental processes are often lacking. In this paper, relatively simple, but science-based, methods are presented that allow researchers, engineers, and water managers to obtain first-order estimates of essential process parameters in estuaries, such as the estuary depth, the tidal amplitude, the tidal excursion, the phase lag, and the salt water intrusion, on the basis of readily obtainable information, such as topographical maps and tidal tables. These apparently simple relationships are assumed to result from the capacity of freely erodible water bodies to adjust themselves to external drivers and to dissipate the free energy from these drivers as efficiently as possible. Thus, it is assumed that these systems operate close to their thermodynamic limit, resulting in predictable patterns that can be described by relatively simple equations. Although still much has to be done to develop an overall physics-based theory, this does not prevent us from making use of the empirical "laws" that we observe in alluvial estuaries.

  5. Southwest Florida Shelf Ecosystems Analysis Study

    National Oceanic and Atmospheric Administration, Department of Commerce — The Southwest Florida Shelf Ecosystems Analysis Study produced grain size analyses in the historic 073 format for 299 sea floor samples collected from October 25,...

  6. Monsoonal impact on planktonic standing stock and abundance in a tropical estuary (Cochin backwaters - India)

    Science.gov (United States)

    Madhu, N. V.; Jyothibabu, R.; Balachandran, K. K.; Honey, U. K.; Martin, G. D.; Vijay, J. G.; Shiyas, C. A.; Gupta, G. V. M.; Achuthankutty, C. T.

    2007-06-01

    Environmental studies in the Cochin backwaters (CBW), a tropical estuary along the southwest coast of India showed that seasonal fluctuations in salinity created by the monsoonal rainfall and associated run off is a major factor controlling the distribution and abundance of micro- and mesozooplankton. During premonsoon season, the CBW was characterized by warm waters (av. 32.6 ± 0.6 °C) with relatively high salinity (>23; except in the lower estuary). On the other hand, fresh water was found to dominate the entire area during monsoon and postmonsoon seasons. The enormous input of nutrients (nitrate, phosphate and silicate) into the estuary from various sources (industries, agriculture and domestic) was responsible for the high phytoplankton biomass (av. 10.4 ± 10.1 mg m -3) irrespective of seasons. The phytoplankton community was, in general, dominated by diatoms (av. 88 ± 12%), and proliferation of multiple species of diatoms ( Skeletonema costatum, Thalassiosira subtilis and Nitzschia closterium - 1600 × 10 3 cells L -1) at different locations were observed especially during high saline condition. In case of zooplankton (micro- and meso), high standing stocks (micro av. 81.4 ± 48.1 mg C m -3; meso av. 88 ± 125 mg C m -3, respectively) were recorded during the premonsoon season. Copepods (e.g. Calanoids) formed the abundant group (av. 75 ± 18%) in the mesozooplankton community irrespective of seasons. The ratio of carbon content between phytoplankton and zooplankton ( P: Z) was quite high (>100) during monsoon and postmonsoon seasons, but became low during premonsoon season (food web of Cochin estuarine system is characterized by substantial amount of unconsumed carbon at primary level owing to the reduction in phytoplankton grazers (zooplankton).

  7. Numerical modeling of oil spill in the Patos Lagoon estuary; Modelagem numerica de derrames de oleo no estuario da Lagoa dos Patos

    Energy Technology Data Exchange (ETDEWEB)

    Martinho, Vivian; Monteiro, Igor Oliveira; Janeiro, Joao; Fernandes, Elisa Helena Leao [Fundacao Universidade do Rio Grande (FURG), RS (Brazil)

    2008-07-01

    Navigation is responsible for the input of 555.000 tons of oil per year in the marine environment. The recovery of the system can take dozens of years, affecting economical, ecological and social areas. The Patos Lagoon estuary presents wide importance and high susceptibility to accidents of oil spill. Therefore, the objective of this study is to analyze the spread of oil spills using the MOHID model, which simulates both the hydrodynamics of the estuary and the oil dispersion considering the different processes involved. Wind and water level data from May 1 to August 18, 1999 were used to simulate a hypothetic accident of involving 2000 m3 of oil MF 380 during the passage of a cold front considering high and low river discharges. Results indicate that the oil dispersion is governed by the estuarine dynamic, which is controlled by the wind action and river discharge. Thus, during southwest wind the oil is retained within the estuary, and in situations of northeast wind the oil tends to leave the estuary and sometimes can reach the inner shallow bays. (author)

  8. Estuary wader capacity following severe weather mortality

    International Nuclear Information System (INIS)

    The building of a tidal power barrage across an estuary may lead to substantial changes in its ecology. Many of Britain's estuaries hold internationally important numbers of waders. Careful consideration, therefore, needs to be given to the likely effects of tidal power barrages on wader populations. The opportunity for increased understanding of the mechanisms which govern wader populations was provided by a period of severe winter weather in 1991, which resulted in a substantial mortality of waders in eastern England. Such conditions are known to be stressful to birds and the study objectives were to investigate both the effects of and recovery from severe weather. (author)

  9. Mercury enrichment in sediments of Amba estuary

    Digital Repository Service at National Institute of Oceanography (India)

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

    2009-01-01

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

  10. Trona resources in southwest Wyoming

    Science.gov (United States)

    Dyni, J.R.; Wiig, S.V.; Grundy, W.D.

    1995-01-01

    Bedded trona (Na2CO3??NaHCO3??2H2O) in the lacustrine Green River Formation of Eocene age in the Green River Basin, southwest Wyoming, constitutes the largest known resource of natural sodium carbonate in the world. In this study, 116 gigatons (Gt) of trona ore are estimated to be present in 22 beds, ranging from 1.2 to 11 meters (m) in thickness. Of this total, 69 Gt of trona ore are estimated to be in beds containing less than 2 percent halite and 47 Gt in beds containing 2 or more percent halite. These 22 beds underlie areas of about 130 to more than 2,000 km2 at depths ranging from about 200 m to more than 900 m below the surface. The total resource of trona ore in the basin for which drilling information is available is estimated to be about 135 Gt. Underveloped trona beds in the deeper southern part of the basin may be best developed by solution mining. Additional unevaluated sodium carbonate resources are present in disseminated shortite (Na2CO3??2CaCO3) in strata interbedded with the trona and in shallow sodium carbonate brines in the northeast part of the basin. Estimates of the shortite and brine resources were not made. ?? 1995 Oxford University Press.

  11. Kaua'i: Streams and Estuaries.

    Science.gov (United States)

    Hawkins, John, Ed.; Murakami, Colleen, Ed.

    Designed to help teachers develop students' awareness and understanding of some of Hawaii's endangered aquatic resources, this module contains activities and instructional suggestions for use with intermediate as well as high school students. The module is divided into two sections which explore the streams and estuaries of Kauai. Activities in…

  12. Nutrient elements in large Chinese estuaries

    Science.gov (United States)

    Zhang, Jing

    1996-07-01

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

  13. Nutrient budgets for large Chinese estuaries

    Science.gov (United States)

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

    2009-10-01

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

  14. Carbon dioxide emissions from Indian monsoonal estuaries

    Digital Repository Service at National Institute of Oceanography (India)

    Sarma, V.V.S.S.; Viswanadham, R.; Rao, G.D.; Prasad, V.R.; Kumar, B.S.K.; Naidu, S.A.; Kumar, N.A.; Rao, D.B.; Sridevi, T.; Krishna, M.S.; Reddy, N.P.C.; Sadhuram, Y.; Murty, T.V.R.

    2012-01-01

    estuaries. The mean pCO sub(2) and particulate organic carbon (POC) showed positive relation with rate of discharge suggesting availability of high quantities of organic matter that led to enhanced microbial decomposition. The annual CO sub(2) fluxes from...

  15. INDICATORS OF ECOSYSTEM INTEGRITY FOR ESTUARIES

    Science.gov (United States)

    Jordan, Stephen J. and Lisa M. Smith. In press. Indicators of Ecosystem Integrity for Estuaries. In: Proceedings of the Estuarine Indicators Workshop, 29-31 October 2003, Sanibel Island, FL. Sanibel-Captiva Conservation Foundation, Sanibel, FL. 23 p. (ERL,GB 1194). Ideal ...

  16. Estuaries and Tidal Marshes. Habitat Pac.

    Science.gov (United States)

    Fish and Wildlife Service (Dept. of Interior), Washington, DC.

    This educational packet consists of an overview, three lesson plans, student data sheets, and a poster. The overview examines estuaries and tidal or salt marshes by discussing the plants and animals in these habitats, marsh productivity, benefits and management of the habitats, historical aspects, and development and pollution. A glossary and list…

  17. Epipelic diatoms in the estuaries of South Africa

    Scientific Electronic Library Online (English)

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

    2013-01-01

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

  18. Nutrient budgets for large Chinese estuaries

    Directory of Open Access Journals (Sweden)

    S. M. Liu

    2009-10-01

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

  19. Current Characterization at the Amazon estuary

    Science.gov (United States)

    Bezerra, M. O.

    2009-04-01

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

  20. SOUTHWEST REGIONAL PARTNERSHIP ON CARBON SEQUESTRATION

    Energy Technology Data Exchange (ETDEWEB)

    Brian McPherson; Rick Allis; Barry Biediger; Joel Brown; Jim Cappa; George Guthrie; Richard Hughes; Eugene Kim; Robert Lee; Dennis Leppin; Charles Mankin; Orman Paananen; Rajesh Pawar; Tarla Peterson; Steve Rauzi; Jerry Stuth; Genevieve Young

    2004-11-01

    The Southwest Partnership Region includes six whole states, including Arizona, Colorado, Kansas, New Mexico, Oklahoma, and Utah, roughly one-third of Texas, and significant portions of adjacent states. The Partnership comprises a large, diverse group of expert organizations and individuals specializing in carbon sequestration science and engineering, as well as public policy and outreach. The main objective of the Southwest Partnership project is to achieve an 18% reduction in carbon intensity by 2012. The Partnership made great progress in this first year. Action plans for possible Phase II carbon sequestration pilot tests in the region are almost finished, including both technical and non-technical aspects necessary for developing and carrying out these pilot tests. All partners in the Partnership are taking an active role in evaluating and ranking optimum sites and technologies for capture and storage of CO{sub 2} in the Southwest Region. We are identifying potential gaps in all aspects of potential sequestration deployment issues.

  1. 33 CFR 165.1190 - Security Zone; San Francisco Bay, Oakland Estuary, Alameda, CA.

    Science.gov (United States)

    2010-07-01

    ... Security Zone; San Francisco Bay, Oakland Estuary, Alameda, CA. 165.1190... Security Zone; San Francisco Bay, Oakland Estuary, Alameda, CA. (a) Location...security zone: All navigable waters of the Oakland Estuary, California, from the...

  2. Hydrologic Literacy in the Southwest

    Science.gov (United States)

    Washburne, J.; Madden, J.

    2008-12-01

    Improving hydrologic literacy at all levels has been the keystone to the education mission at NSF's SAHRA Science and Technology Center since its inception in 2000. Water issues and water education are particularly relevant in the semi-arid southwest, which has experienced a series of droughts and tremendous growth throughout this period. One of our strategies has been to focus our efforts on the high school and undergraduate level, for which there are far fewer water education materials available. Early on, we worked with local water educators and employed an Understanding by Design methodology to develop a series of Enduring Understandings in the critical areas of water quality, aquatic life, watersheds and urban hydrology. These basic concepts have helped guide our development of content and training opportunities. A prime example of this process is our Watershed Visualization project, which includes a series of animated videos focused on understanding the geographic and hydrologic setting of the Verde Watershed in central Arizona. This series also addresses the interaction of climate and groundwater recharge in this rapidly changing area. This past year, we developed a new program called Arizona Rivers, which emphasizes local and student- based monitoring and research of the interactions between riparian hydrology and ecology. One key feature of this program is an extended summer field trip/research experience for high school students called the Riparian Research Experience. A goal of this program is to raise the level of critical analysis and environmental stewardship among high school students and their teachers. A more comprehensive effort of raising the hydrologic literacy of non-science university freshman has been taking place at the University of Arizona for the past five years through the general education course titled Arizona Water Issues or HWR203. This course focuses equally on fundamental hydrologic understandings, beginning with the water cycle as well as the host of political and social issues that arise as this scarce resource is stretched among many stakeholders claiming ever larger water needs. This course covers a range of topics from water law to water resource management using decision support modeling tools. All of these projects can be found on our web site referenced below.

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

    Directory of Open Access Journals (Sweden)

    A. Shivaprasad

    2012-07-01

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

  4. Small estuary, big port - progress in the management of the Stour-Orwell Estuary system

    Science.gov (United States)

    Spearman, Jeremy; Baugh, John; Feates, Nigel; Dearnaley, Mike; Eccles, Dan

    2014-10-01

    Management of port development is increasingly challenging because of the competitive requirement for deeper channels and because of the need to preserve important coastal wetlands which function as both habitat and flood defence. This paper describes the management of the Stour/Orwell Estuary system, Eastern England, an estuary system which has experienced considerable development and morphological change. The estuary is internationally important for its wetland bird populations and the intertidal areas of the estuary system are protected under European legislation. It is also the location of the Port of Felixstowe. In 1998/2000 the approach channel to the Port of Felixstowe was deepened from -12.5 mCD to -14.5 mCD. This paper describes the effects of the approach channel deepening, the approach taken to identifying the potential impact to intertidal habitat resulting from the deepening, the sediment recycling implemented as mitigation to prevent increased loss of habitat and the subsequent response of the estuary system to this intervention.

  5. A fully predictive model for salt intrusion in estuaries applied to the Yangtze estuary

    Science.gov (United States)

    Cai, Huayang; Savenije, Hubert H. G.; Zuo, Shuhua; Jiang, Chenjuan; Chua, Vivien P.

    2015-04-01

    Understanding the way the salinity distribution in an estuary reacts to external drivers (e.g., tide, fresh water discharge, dredging etc.) is important for both water quality and water resources management in estuaries. The salinity distribution depends strongly on the geometry of an estuary, but also on the fresh water discharge that counteracts the salt intrusion. In estuaries it is notoriously hard to estimate this discharge and subsequently to predict the parameters that determine the mixing behaviour depending on it. Recently a method has been developed to predict the fresh water discharge on the basis of water level observations. In addition predictive equations for tidal mixing have been updated and revised. In this paper, these two predictive methods are combined and subsequently applied to the Yangtze estuary under a wide variation of fresh water discharge. The predicted salt distribution appears to be in good agreement with observations. To provide insight into the optimum use of water resources (e.g., to determine the amount of fresh water discharge required to maintain a specific salt intrusion length), we further studied the salt intrusion pattern under different fresh water discharge conditions.

  6. Plankton food web and its seasonal dynamics in a large monsoonal estuary (Cochin backwaters, India)-significance of mesohaline region.

    Science.gov (United States)

    Sooria, P M; Jyothibabu, R; Anjusha, A; Vineetha, G; Vinita, J; Lallu, K R; Paul, M; Jagadeesan, L

    2015-07-01

    The paper presents the ecology and dynamics of plankton food web in the Cochin backwaters (CBW), the largest monsoonal estuary along the west coast of India. The data source is a time series measurement carried out in the CBW during the Spring Intermonsoon (March-May) and the Southwest Monsoon (June-September). The plankton food web consisting of autotrophic/heterotrophic picoplankton, autotrophic/heterotrophic nanoplankton, microzooplankton, and mesozooplankton was quantified in relation to the seasonal hydrographical settings in the CBW. The study showed that significant changes in the abundance and dynamics of plankton food web components were governed mostly by the spatial and seasonal changes in hydrography rather than short-term changes induced by tide. During the Spring Intermonsoon, all plankton consumers in the CBW was higher than the Southwest Monsoon, and the trophic interaction was more effective in upstream where there was a close coupling between all prey components and their consumers. During the Southwest Monsoon, on the other hand, the trophic interaction was more effective downstream where the abundance of all plankton consumers was significantly higher than the upstream. Based on statistical analyses NMDS/SIMPROF and RDA, we demarcated the spatial difference/mismatch in the prey and consumer distribution in the CBW and showed that a more efficient plankton food web exists in the mesohaline regions during both seasons. This suggests that a noticeable spatial shift occurs seasonally in the active plankton food web zone in the CBW; it is upstream during the Spring Intermonsoon and downstream during the Southwest Monsoon. PMID:26070995

  7. Nutrients, hypoxia and Mass Fishkill events in Tapi Estuary, India

    Science.gov (United States)

    Ram, Anirudh; Jaiswar, Jiyalal Ram M.; Rokade, M. A.; Bharti, S.; Vishwasrao, C.; Majithiya, D.

    2014-07-01

    From 1983 to 2011, dissolved oxygen (DO) conditions in the Tapi Estuary changed from normoxic to hypoxic due to increased and untreated discharge of sewage. Both tidal and day-night variations of DO were best explained by hydrographic factors, sewage pollution and phytoplankton dynamics in upper, middle, lower estuary and the coastal water. Hypoxia/anoxia was associated with low-flow periods due to riverine restrictions and changing in climatic condition. The upper Tapi Estuary becomes anoxic during summer irrespective of tide while the middle estuary was anoxic (hypoxia.

  8. Estuaries, sediments and shorebirds 2: shorebird usage of intertidal areas

    International Nuclear Information System (INIS)

    The United Kingdom has some of the most promising sites in Western Europe for tidal energy barrage schemes, however their acceptability will partly depend on longer term environmental effects particularly on estuarine ecosystems. Estuaries around the British Isles support internationally important waterfowl populations, which could be affected by possible future barrage schemes. Three linked projects have been funded under the DTI's tidal energy generic environmental programme to develop a predictive methodology for correlating estuary bird populations to sediments. This study summarises bird usage in a sample of 27 estuaries and relates communities of waterfowl on estuaries to a suite of environmental and sediment cover variables. (author)

  9. Marine geology of the St. Lawrence Estuary

    Energy Technology Data Exchange (ETDEWEB)

    St-Onge, Guillaume [Canada Research Chair in Marine Geology, Institut des sciences de la mer de Rimouski (ISMER) and GEOTOP Research Center, 310 allee des Ursulines, Rimouski, Quebec, G5L 3A1 (Canada); Duchesne, Mathieu J [Geological Survey of Canada, Quebec Division, 490 de la Couronne, Quebec City, Quebec, G1K 9A9 (Canada); Lajeunesse, Patrick, E-mail: guillaume_st-onge@uqar.qc.ca [Departement de geographie and Centre d' etudes nordiques, Universite Laval, Quebec City, Quebec, G1V 0A6 (Canada)

    2011-05-15

    The St. Lawrence Estuary, Eastern Canada, contains a very thick (>450 m) Quaternary sedimentary sequence. The results from recently conducted geophysical surveys in conjunction with piston coring indicate that these sediments were deposited under very high sedimentation rates, sometimes as high as {approx}30 m/ka during the last deglaciation. Results also reveal evidence of large submarine landslides during the Holocene, changes in sedimentation rates and the significant role of submarine canyons and channels to transfer sediments from the coast to the deeper marine environment. Finally, this paper highlights the presence of more than 1900 pockmarks on the seafloor of the St. Lawrence Estuary and discusses their possible origins: active hydrocarbon seeps in the Laurentian Channel and biogenic gas seepage on the northwestern shoulder of the Laurentian Channel.

  10. Eutrophication in a western Australian estuary

    OpenAIRE

    Hodgkin, E. P.; Birch, P B

    1982-01-01

    Two large, shallow (2m) coastal lagoons of south western Australia have become eutrophic during the last 20 years. Abundant benthic green algae (principally Cladophora aff. albida and Chaetomorpha spp.) accumulate on the shores of one and there are dense phytoplankton blooms of the blue-green Nodularia spumigena in the other. The eutrophy is caused by a great increase in the amount of nutrients, especially phosphorus (phosphatic fertilizers). Tidal range is small and exchage between estuary a...

  11. Tidal Propagation in a Branching Tidal Estuary

    Science.gov (United States)

    Wagner, R.; Stacey, M. T.

    2012-12-01

    In branching tidal systems, tidal dissipation, propagation and reflection together define the spatial distribution of tidal energy. When specific locations or regions are altered, for example through the restoration of tidal marsh, there is uncertainty as to how the system will respond, including the spatial influence of the changes. When tidal marsh habitat is restored, it creates local tidal dissipation which may alter tidal energy in other parts of the estuary, potentially altering the function of tidal marshes elsewhere. It is important that this interaction be analyzed and understood before management decisions are made. We present results of a simple analytic model of tidal propagation in a branching system. We develop wave equations for along-channel velocity and wave height which account for friction and changes in channel geometry. By linearizing the friction term in the depth-averaged along-channel momentum equation and including an amplification factor in the wave form, then combining it with the continuity equation, we solve for wave speed and amplification as a function of friction and channel geometry. We also solve for the tidal velocity and stage as a function of position and time. Using this solution within an idealized branching channel estuary and applying matching conditions at the branches, we analyze the effects of changes to the geometry or reflection characteristics of one branch on tidal regimes throughout the estuary.

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

    Science.gov (United States)

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

    2014-10-01

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

  13. Fish assemblage structure in relation to environmental conditions in a tropical estuary / Ensamblaje estructural de peces en relación a las condiciones ambientales en un estuario tropical

    Scientific Electronic Library Online (English)

    Alicia, González-Solis; Daniel, Torruco.

    2013-12-01

    Full Text Available La estructura de la comunidad de peces del estero de Sabancuy, México, fue analizada durante 2 temporadas climáticas usando datos de abundancia, biomasa y de 14 parámetros ambientales. No se encontraron diferencias estadísticamente significativas entre los datos obtenidos en las 2 estaciones climáti [...] cas. En el estuario se definieron 2 zonas ambientales, una que se extiende desde el sureste hasta el puente de Sabancuy y la otra desde ese sitio hasta la cabeza del estuario. Se registraron un total de 32 especies de peces representando a 21 familias. Las familias más abundantes fueron: Gerridae, Sciaenidae, Sparidae, Lutjanidae y Ciprinodontidae. La diversidad fue alta en el centro de la laguna. La clasificación comunitaria dió como resultado 3 ensamblajes con diferencias notables en la distribución espacial. Una muestra la influencia de la comunicación del estuario con la laguna de Términos, la segunda muestra la cabeza del estuario y la tercera una zona transicional cerca del puente que divide al estuario. La organización ecológica del estuario estuvo dividida en 2 áreas por el puente, con relativa escasez de hábitats y alimento y una consecuente pobreza de especies en los 2 extremos. La concentración de fosfato tiene la mayor influencia en el ensamblaje de la comunidad de peces. Abstract in english Fish community in Sabancuy Estuary, Mexico, was analyzed during 2 a dry and a rainy seasons using 14 environmental parameters and fish species abundance and biomass data. No significant differences in data were observed between seasons. Two environmental zones were defined within the estuary, one ex [...] tending southwest from a bridge and the other northeast from the bridge to the estuary head. A total of 21 fish families and 32 species were recorded. The most abundant families were Gerridae, Sciaenidae, Sparidae, Lutjanidae and Ciprinodontidae. Diversity was high in the central lagoon. Fish community classification resulted in 3 assemblages with notable differences in spatial distribution. One was influenced by estuary communication with Terminos Lagoon, a second was at the estuary head and a third at the transitional zone near the bridge dividing the estuary. Ecological organization of the Estuary was divided into 2 areas by the bridge, with relative habitat and food resource scarcity and consequent species paucity at the 2 extremes. Phosphate concentrations had the most influence on fish community assemblage.

  14. Southwest Regional Partnership on Carbon Sequestration

    Energy Technology Data Exchange (ETDEWEB)

    Brian McPherson

    2006-03-31

    The Southwest Partnership on Carbon Sequestration completed its Phase I program in December 2005. The main objective of the Southwest Partnership Phase I project was to evaluate and demonstrate the means for achieving an 18% reduction in carbon intensity by 2012. Many other goals were accomplished on the way to this objective, including (1) analysis of CO{sub 2} storage options in the region, including characterization of storage capacities and transportation options, (2) analysis and summary of CO{sub 2} sources, (3) analysis and summary of CO{sub 2} separation and capture technologies employed in the region, (4) evaluation and ranking of the most appropriate sequestration technologies for capture and storage of CO{sub 2} in the Southwest Region, (5) dissemination of existing regulatory/permitting requirements, and (6) assessing and initiating public knowledge and acceptance of possible sequestration approaches. Results of the Southwest Partnership's Phase I evaluation suggested that the most convenient and practical ''first opportunities'' for sequestration would lie along existing CO{sub 2} pipelines in the region. Action plans for six Phase II validation tests in the region were developed, with a portfolio that includes four geologic pilot tests distributed among Utah, New Mexico, and Texas. The Partnership will also conduct a regional terrestrial sequestration pilot program focusing on improved terrestrial MMV methods and reporting approaches specific for the Southwest region. The sixth and final validation test consists of a local-scale terrestrial pilot involving restoration of riparian lands for sequestration purposes. The validation test will use desalinated waters produced from one of the geologic pilot tests. The Southwest Regional Partnership comprises a large, diverse group of expert organizations and individuals specializing in carbon sequestration science and engineering, as well as public policy and outreach. These partners include 21 state government agencies and universities, five major electric utility companies, seven oil, gas and coal companies, three federal agencies, the Navajo Nation, several NGOs, and the Western Governors Association. This group is continuing its work in the Phase II Validation Program, slated to conclude in 2009.

  15. Time-dependence of salinity in monsoonal estuaries

    Digital Repository Service at National Institute of Oceanography (India)

    Vijith, V.; Sundar, D.; Shetye, S.R.

    2009-01-01

    The theories and classification schemes commonly used for understanding estuarine dynamics often refer to a steady state of the estuary in which the salinity field is time-independent. In this state salinity-ingress into the estuary due to different...

  16. SALINE VEGETATION OF MOLOCHNY ESTUARY COAST: DISTRIBUTION PATTERNS

    Directory of Open Access Journals (Sweden)

    Namlieva L. M.

    2011-11-01

    Full Text Available The patterns of distributing of halophytic vegetation in North–Western Priazov’ya on the whole and on the coast of the Molochny estuary, in particular were considered. The distribution caused by the location of saline soils and degree of their salinity. The vegetation of saline soils can be expressly divided into two groups: vegetation of marine and estuaries banks, and vegetation of saline lands. The natural vegetation of right bank of the Molochny estuary tested considerable anthropogenic influence, that’s why it is preserved mainly on the steep slope of right bank the estuary. Here, some three groups were selected: vegetation of near-estuary part, vegetation of slope of the right bank, and vegetation of uplifted plateau.

  17. Early Cambrian sipunculan worms from southwest China.

    OpenAIRE

    Huang, Di-ying; Chen, Jun-yuan; Vannier, Jean; Saiz Salinas, J. I.

    2004-01-01

    We report the discovery of sipunculan worms from the Lower Cambrian Maotianshan Shale, near Kunming (southwest China). Their sipunculan identity is evidenced by the general morphology of the animals (sausage-shaped body with a slender retractable introvert and a wider trunk) and by other features, both external (e.g. perioral crown of tentacles, and hooks, papillae and wrinkle rings on the body surface) and internal (U-shaped gut, and the anus opening near the introvert-trunk junction). The t...

  18. Environmental modulation of the plankton community composition and size-structure along the eutrophic intertidal coast of the Río de la Plata estuary, Argentina

    Directory of Open Access Journals (Sweden)

    Maximiliano D. Garcia

    2014-05-01

    Full Text Available In this study we investigated the spatial distribution of the plankton community, bacterio-, phyto- and zooplankton, in relation with environmental conditions along the intertidal coast of the Río de la Plata estuary, Argentina. Plankton was analyzed in terms of species composition, abundance, biomass (carbon content and size-structure. We aim to evaluate the potential effects of anthropogenic impacts (e.g., nutrient enrichment and physicochemical gradients alongshore (e.g., salinity, turbidity on the composition and functioning of the plankton. We asked whether the natural structuring of the plankton by salinity and turbidity, known to be true of estuaries, is modified by eutrophication along the studied shoreline. We found that the density and biomass of bacteria and phytoplankton were strikingly enhanced by high eutrophication levels along the intertidal southwest coast of the Río de la Plata estuary. We also found that the highest zooplankton density in the most polluted area but the biomass showed a different distribution pattern. Nevertheless, when zooplankton was analyzed by means of its size fraction, we accordingly found that the microzooplankton biomass was positively associated with smaller-size phytoplankton groups and the most polluted study sites. Copepods were the major taxonomic groups that best represented the mesozooplankton biomass. We therefore expected that its distribution was modulated by the presence of its food items (i.e., large cells which, in turn, were more abundant in the middle-outer zone. In contrast, we found that the highest biomass of copepods occurred at the innermost site of the estuary and we found no significant association with other planktonic groups. Overall, this study highlights the noteworthy impacts of human activities modifying the functioning of this coastal ecosystem. The differences found in the taxonomic composition and size structure of the planktonic community assemblage between the most polluted and less polluted sites constitutes an excellent baseline for considering plankton as ecological an indicator of water quality.

  19. Radiocesium transport in the Hudson River Estuary

    International Nuclear Information System (INIS)

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

  20. 40 CFR 81.259 - Southwest Iowa Intrastate Air Quality Control Region.

    Science.gov (United States)

    2010-07-01

    ...Southwest Iowa Intrastate Air Quality Control Region. 81.259 Section...PURPOSES Designation of Air Quality Control Regions § 81.259 Southwest Iowa Intrastate Air Quality Control Region. The Southwest...

  1. Waterfowl migration and distribution in North West estuaries. V. 1

    International Nuclear Information System (INIS)

    Waterfowl populations may be affected by proposed tidal barrage across the Mersey. This study had three objectives:-(1) to evaluate the patterns of usage of the intertidal flats of the Mersey estuary by waders and wildfowl and to establish which are the preferred areas; (2) to identify the places of origin and movement patterns of the populations of waders and wildfowl that visit the Mersey Estuary; and (3) to evaluate evidence regarding the capacity of British estuaries to absorb waders and wildfowl populations which might be displaced by a Mersey Barrage. The text and tables and results only are presented in Volume 1. (author)

  2. Sediment Transport Processes In River Dominated Sub-Tropical Estuaries

    Science.gov (United States)

    DAquino, Carla; Schettini, Carlos

    2014-05-01

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

  3. Distribution of Th-232 and Th-228 in Santos and Sao Vicente Estuary, Sao Paulo, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Silva, P.S.C.; Mazzilli, B.P.; Favaro, D.I.T. [Instituto de Pesquisas Energeticas e Nucleares, Av. Lineu Prestes, 2242, Caixa Postal 05508-000, Cidade Universitaria, Sao Paulo (Brazil)]. e-mail: Pscsilva@ipen.br

    2004-07-01

    In the last decades considerable attention has been given to technologically enhanced natural occurring radioactive material (TENORM). Within this frame, of particular concern is the phosphate fertilizer industry. Santos Basin, located in Southwest Brazil, Sao Paulo State, comprising Santos and Sao Vicente estuarine system, is considered the most important industrial region of the country. Among the industrial activities present, phosphate fertilizer plants are responsible for the production of 69 millions tons of phosphogypsum waste, which is stockpiled in the surrounding environment. This waste concentrates radionuclides of the natural series originally present in the phosphate rock used as raw material. This study aims to evaluate the environmental impact of such activities in the sediments of the estuarine system. {sup 232} Th and {sup 228} Th concentrations in Santos and San Vicente estuary sediments were determined by Neutron activation analysis and Gamma spectrometry, respectively. {sup 232} Th concentration ranged from 6.5 to 198 Bq kg{sup -1} with mean value of 57 {+-} 39 Bq kg{sup -1}, for 42 samples. {sup 228} Th content varied from 12 to 110 Bq kg{sup -1} with a mean value of 74 {+-} 23 Bq kg{sup -1}, for 18 samples. It can be seen that the amount of {sup 232} Th is higher in the rivers close to the phosphogypsum piles, at least five points were identified as being affected by anthropogenic factor. (Author)

  4. Distribution of Th-232 and Th-228 in Santos and Sao Vicente Estuary, Sao Paulo, Brazil

    International Nuclear Information System (INIS)

    In the last decades considerable attention has been given to technologically enhanced natural occurring radioactive material (TENORM). Within this frame, of particular concern is the phosphate fertilizer industry. Santos Basin, located in Southwest Brazil, Sao Paulo State, comprising Santos and Sao Vicente estuarine system, is considered the most important industrial region of the country. Among the industrial activities present, phosphate fertilizer plants are responsible for the production of 69 millions tons of phosphogypsum waste, which is stockpiled in the surrounding environment. This waste concentrates radionuclides of the natural series originally present in the phosphate rock used as raw material. This study aims to evaluate the environmental impact of such activities in the sediments of the estuarine system. 232 Th and 228 Th concentrations in Santos and San Vicente estuary sediments were determined by Neutron activation analysis and Gamma spectrometry, respectively. 232 Th concentration ranged from 6.5 to 198 Bq kg-1 with mean value of 57 ± 39 Bq kg-1, for 42 samples. 228 Th content varied from 12 to 110 Bq kg-1 with a mean value of 74 ± 23 Bq kg-1, for 18 samples. It can be seen that the amount of 232 Th is higher in the rivers close to the phosphogypsum piles, at least five points were identified as being affected by anthropogenic factor. (Author)

  5. Seasonal Abundance of Micro Algae in Pandi Backwaters of Godavari Estuary, Andhra Pradesh, India

    Directory of Open Access Journals (Sweden)

    Prayaga Murty PRAGADA

    2010-09-01

    Full Text Available Gautami branch of Godavari River is a typical positive estuary and is in tidal communication with the open sea upto a point near Kapileswarapuram. This branch flows southwest and opens into Bay of Bengal at two places, namely Bhiravapalem and Kothapalem. The Gautami branch of Godavari is also connected to Pandi backwaters by a channel known as Pedderu, which starts at Kothapalem, Balusutippa area and enters Pandi back water system. Two stations were selected for collection of data. Hydrographical data were collected for one year from July 2006 to 2007 and the data on distribution of phytoplankton was studied in three seasons during 2006-2007. Hydrographical features of the two stations showed that lower values were recorded during October to February months, while higher values were reported from the month of March to September. A total 57 species of phytoplankton were identified from the two study sites of the Pandi backwaters Composition of phytoplankton varied seasonally in relation to salinity fluctuations and showed that two peak periods, one in June-July and another in between December and March. Present study indicates that diatoms are the dominant group followed by the Chlorophyceae and others. This study will aid the baseline data for aqua-culturists in nearby regions.

  6. Southwest coast of Greenland and Davis Strait

    Science.gov (United States)

    2002-01-01

    This true-color image was taken by MODIS as it passed over the southwest coast of Greenland (right) and the Davis Strait (center and left). The Davis Strait connects Baffin Bay to the north and the Labrador Sea to the south, and separates Greenland from Baffin Island, Canada. The Davis Strait is part of the Northwest Passage, a navigable seaway connecting the Atlantic Ocean and the Pacific Ocean. The image shows the prevailing currents in the area, with the warm water of a branch of the North Atlantic Drift flowing northward along the Greenland coast, and the cold, iceberg-filled Labrador Current flowing southward along the Baffin Island coast.

  7. "Taiko Southwest": Developing a "New" Musical Tradition in English Schools

    Science.gov (United States)

    Hennessy, Sarah

    2005-01-01

    This article reports on a project to establish taiko drumming groups in schools throughout the southwest of England. The project is funded by the National Foundation for Youth Music (YM) which aims to increase access to music-making activity for young people in the UK. Taiko is a relatively new phenomenon in the UK. In the southwest, Kagemusha…

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

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

  9. MODIS water quality algorithms for northwest Florida estuaries

    Science.gov (United States)

    Synoptic and frequent monitoring of water quality parameters from satellite is useful for determining the health of aquatic ecosystems and development of effective management strategies. Northwest Florida estuaries are classified as optically-complex, or waters influenced by chlo...

  10. Heavy metal accumulation in a flow restricted, tropical estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Balachandran, K.K.; Laluraj, C.M.; Nair, M.; Joseph, T.; Sheeba, P.; Venugopal, P.

    2005-01-01

    Levels of heavy metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn), organic carbon content and textural characteristics in the surficial sediments of Cochin estuary (SW coast of India) and adjacent coast are presented. Anthropogenic inputs from...

  11. Habitat Scale Mapping of Fisheries Ecosystem Service Values in Estuaries

    Directory of Open Access Journals (Sweden)

    Steve J. Jordan

    2010-12-01

    Full Text Available Little is known about the variability of ecosystem service values at spatial scales most relevant to local decision makers. Competing definitions of ecosystem services, the paucity of ecological and economic information, and the lack of standardization in methodology are major obstacles to applying the ecosystem-services approach at the estuary scale. We present a standardized method that combines habitat maps and habitat–faunal associations to estimate ecosystem service values for recreational and commercial fisheries in estuaries. Three case studies in estuaries on the U.S. west coast (Yaquina Bay, Oregon, east coast (Lagoon Pond, Massachusetts, and the Gulf of Mexico (Weeks Bay, Alabama are presented to illustrate our method’s rigor and limitations using available data. The resulting spatially explicit maps of fisheries ecosystem service values show within and between estuary variations in the value of estuarine habitat types that can be used to make better informed resource-management decisions.

  12. Gulf of Mexico Estuaries - Tampa Bay (BASIS# 20900J2)

    National Oceanic and Atmospheric Administration, Department of Commerce — Many of the nation's estuaries have been environmentally stressed since the turn of the 20th century and will continue to be impacted in the future. Tampa Bay, one...

  13. Bacterial contamination of mussels at Mahe estuary, Malabar coast

    Digital Repository Service at National Institute of Oceanography (India)

    Gore, P.S.; Raveendran, O.; Iyer, T.S.G.; Varma, P.R.G.; Sankaranarayanan, V.N.

    1992-01-01

    Mussel samples from the mussel bed and near-by market, beach sand, sediment and water from the Mahe Estuary, Kerala, India were analysed for the bacterial quality. Indicator bacteria such as Escherichia coli and faecal streptococci were isolated...

  14. Organic carbon in the sediments of Mandovi estuary, Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Alagarsamy, R.

    1991-01-01

    .95%). During monsoon, spatial variation shows increasing values of TOC in the upper reaches of the estuary. Sewage discharges, primary production and land derived material are considered to be the source of organic carbon...

  15. The larvae of decapods and fishes of Amba estuary, Maharashtra

    Digital Repository Service at National Institute of Oceanography (India)

    Paulinose, V.T.; Devi, C.B.L.; Govindan, K.; Gajbhiye, S.N.; Nair, V.R.

    2004-01-01

    Larvae of fishes and decapods found in zooplankton collections from two stations (Mankule and Patalganga) in Amba estuary adjoining Mumbai harbour were studied during 1989-90 covering three seasons. The percentage contributions of decapods and fish...

  16. Nutrients, hypoxia and mass fishkill events in Tapi estuary, India.

    Digital Repository Service at National Institute of Oceanography (India)

    Ram, A.; JiyalalRam, M.J.; Rokade, M.A.; Bharti, S.; Vishwasrao, C.; Majithiya, D.

    2014-01-01

    From 1983 to 2011, dissolved oxygen (DO) conditions in the Tapi Estuary changed from normoxic to hypoxic due to increased and untreated discharge of sewage. Both tidal and day–night variations of DO were best explained by hydrographic factors...

  17. Seasonal shift in net ecosystem production in a tropical estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Ram, A.S.P.; Nair, S.; Chandramohan, D.

    2003-01-01

    Net ecosystem production was examined in the Mandovi and Zuari estuaries (southwestern India) and the adjoining coastal waters for a period of 1 yr (January to December 1998). The study period encompassed premonsoon, monsoon, and postmonsoon seasons...

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

    Scientific Electronic Library Online (English)

    Stephen, Hosking.

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

  19. Reprint of Water renewal timescales in the Scheldt Estuary

    Science.gov (United States)

    de Brye, Benjamin; de Brauwere, Anouk; Gourgue, Olivier; Delhez, Eric J. M.; Deleersnijder, Eric

    2013-12-01

    Using the concepts of the Constituent-oriented Age and Residence time Theory (CART), we compute timescales related to the water renewal in the Scheldt Estuary (The Netherlands/Belgium). Three different timescales are used to better understand and characterize the dynamics of the estuary: the age of the renewing water, the residence time and the exposure time. The residence time is the time taken by a water parcel to leave the estuary for the first time while the exposure time is the total time spent by a water parcel in the estuary including re-entries. The age of a renewing water parcel is defined as the time elapsed since it entered the estuary. The renewing water was split into three types: the water originating from the sea, the water originating from the upstream fresh tidal rivers and the water originating from the different canals and docks connected to the estuary. Every timescale is computed at any time and position by means of the finite-element, unstructured-mesh model SLIM. This results in movies of the timescale fields (shown as Supplementary material), allowing a detailed analysis of their spatial and temporal variabilities. The effect of the M2 tide and the discharge regime (winter, summer or average situation) on the timescales is also investigated.Tidally-averaged timescales vary little over the width of the estuary and hence exhibit a virtually one-dimensional behaviour. However, around these average values, the timescales can vary hugely over a tidal cycle, with amplitudes that significantly depend on the space coordinates. The reason thereof has yet to be elucidated. These results underscore the need for two- or three-dimensional models with high temporal resolution for investigating the dynamics of the Scheldt Estuary.

  20. Contamination and restoration of an estuary affected by phosphogypsum releases.

    Science.gov (United States)

    Villa, M; Mosqueda, F; Hurtado, S; Mantero, J; Manjón, G; Periañez, R; Vaca, F; García-Tenorio, R

    2009-12-15

    The Huelva Estuary in Huelva, Spain, has been one of the most studied environmental compartments in the past years from the point of view of naturally occurring radioactive material (NORM) releases. It has been historically affected by waste releases, enriched in radionuclides from the U-decay series, from factories located in the area devoted to the production of phosphoric acid and phosphate fertilizers. Nevertheless, changes in national regulations forced a new waste management practice in 1998, prohibiting releases of phosphogypsum into the rivers. The input of natural radionuclides from phosphate factories to rivers was drastically reduced. Because of this there was a unique opportunity for the study of the response of a contaminated environmental compartment, specifically an estuary affected by tidal influences, after the cessation of the contaminant releases to, in this case, the Huelva Estuary (henceforth referred to as the Estuary). To investigate the environmental response to this new discharge regime, the specific activities of radionuclides 226Ra and 210Pb in water and sediment samples collected in four campaigns (from 1999 to 2005) were determined and compared with pre-1998 values. From this study it is possible to infer the most effective mechanisms of decontamination for the Estuary. Decontamination rates of 210Pb and 226Ra in the sediments and water have been calculated using exponential fittings and corresponding half-lives have been deduced from them. The cleaning half-life in the whole area of the Estuary is about 6 and 3.5 years for 226Ra and 210Pb respectively. The observed trend clearly shows that contamination of the Estuary by natural radionuclides is now decreasing and radioactive levels in waters and sediments are approaching the natural background references. This work attempts to evaluate whether it can be expected that the decontamination of the enhanced levels of natural radioactivity in the Estuary can be performed via natural processes. PMID:19822348

  1. Contamination and restoration of an estuary affected by phosphogypsum releases

    International Nuclear Information System (INIS)

    The Huelva Estuary in Huelva, Spain, has been one of the most studied environmental compartments in the past years from the point of view of naturally occurring radioactive material (NORM) releases. It has been historically affected by waste releases, enriched in radionuclides from the U-decay series, from factories located in the area devoted to the production of phosphoric acid and phosphate fertilizers. Nevertheless, changes in national regulations forced a new waste management practice in 1998, prohibiting releases of phosphogypsum into the rivers. The input of natural radionuclides from phosphate factories to rivers was drastically reduced. Because of this there was a unique opportunity for the study of the response of a contaminated environmental compartment, specifically an estuary affected by tidal influences, after the cessation of the contaminant releases to, in this case, the Huelva Estuary (henceforth referred to as the Estuary). To investigate the environmental response to this new discharge regime, the specific activities of radionuclides 226Ra and 210Pb in water and sediment samples collected in four campaigns (from 1999 to 2005) were determined and compared with pre-1998 values. From this study it is possible to infer the most effective mechanisms of decontamination for the Estuary. Decontamination rates of 210Pb and 226Ra in the sediments and water have been calculated using exponential fittings and correspoed using exponential fittings and corresponding half-lives have been deduced from them. The cleaning half-life in the whole area of the Estuary is about 6 and 3.5 years for 226Ra and 210Pb respectively. The observed trend clearly shows that contamination of the Estuary by natural radionuclides is now decreasing and radioactive levels in waters and sediments are approaching the natural background references. This work attempts to evaluate whether it can be expected that the decontamination of the enhanced levels of natural radioactivity in the Estuary can be performed via natural processes.

  2. Nutrient cycling and plant dynamics in estuaries: A brief review

    OpenAIRE

    Flindt, Mogens R.; Pardal, Miguel Ângelo; Lillebø, Ana Isabel; Martins, Irene; Marques, João Carlos

    1999-01-01

    Eutrophication of European estuaries due to massive nutrient loading from urban areas and diffuse runoff from extensively cultivated land areas is analysed. Consequences for the ecology of estuaries, namely changes in plant species composition, which also affects heterotrophic organisms, are approached based on examples showing that the result is often a fundamental structural change of the ecosystem, from a grazing and/or nutrient controlled stable systems to unstable detritus/mineralisation...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-02-01

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

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

    International Nuclear Information System (INIS)

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

  5. Toxic metals enrichment in the surficial sediments of a eutrophic tropical estuary (Cochin Backwaters, Southwest coast of India)

    Digital Repository Service at National Institute of Oceanography (India)

    Martin, G.D.; Rejomon G.; Shaiju, P.; Muraleedharan, K.R.; Nair, S.M.; Chandramohanakumar, N.

    2012-01-01

    Concentrations and distributions of trace metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in surficial sediments of the Cochin backwaters were studied during both monsoon and pre-monsoon periods. Spatial variations were in accordance with textural...

  6. Evolution of Swarna estuary and its impact on braided islands and estuarine banks, Southwest coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    AvinashKumar; Jayappa, K.S.; Vethamony, P.

    2012-01-01

    stream_size 45025 stream_content_type text/plain stream_name Environ_Earth_Sci_65_835a.pdf.txt stream_source_info Environ_Earth_Sci_65_835a.pdf.txt Content-Encoding UTF-8 Content-Type text/plain; charset=UTF-8 1 Author version... are of equal intensity, the waves and currents quickly rework the river-borne sediments. The resultant coastline will have marine built landforms with spits and barriers growing in the direction of dominant littoral drift (Write and Coleman 1973; Chakrabarty...

  7. Frequency of twinning in southwest Nigeria

    Directory of Open Access Journals (Sweden)

    Akinboro A

    2008-01-01

    Full Text Available Background: In the human species, twin is a type of multiple birth in which the mother gives birth to two offspring from the same pregnancy. The occurrence and frequency of twinning, however, varies across human populations. The maternal age, socio-environmental factors, increase in the use of contraceptives, the race of human population, increase in the spontaneous abortion rate, and seasonal variations are among the factors that could influence twinning rate. Information on twinning rates in southwest Nigeria is limited. Aims : This study presents information on the frequency of twinning, as well as its analysis by maternal age, in four urban settings in southwest Nigeria. This is with the aim of extending current knowledge on the frequency of twinning in southwest Nigeria and contributing to the demographic studies in the country. Materials and Methods: Data on single births and twin births from January 1995 to December 2004 were collected from the Oyo State General Hospital (OSGH, Wesley Guild Hospital (WGH, Obafemi Awolowo University Teaching Hospital (OAUTH, and Ekiti State Specialist Hospital (ESSH in Ogbomoso, Ilesa, Ile-Ife, and Ado-Ekiti respectively. These were analyzed by year and maternal age groups of 15-19, 20-24, 25-29, 30-34, 35-39, 40-44, and 45-49 years according to the standard method. Results: A frequency of twin births of 46.5 per 1000 deliveries and 46.2 per 1000 deliveries was recorded for Ilesa and Ile-Ife respectively. The frequency recorded for Ogbomoso and Ado-Ekiti was 38.5 and 22.1 per 1000 deliveries respectively. The overall average frequency of 40.2 per 1000 deliveries for the four hospitals ranks among the highest recorded rates of twin births in the world. The maternal age group of 25-29 years had the highest occurrence of twin births, while the lowest was recorded in the 45-49 years age group. Conclusion: This analysis reveals high incidence of twinning in the studied areas and supports previous assertion that the southwestern part of Nigeria has the highest twinning rate in the country and in the whole world. It is our opinion that diet, maternal history of twinning, and some socio-environmental factors may have influenced the results.

  8. Diagenesis and bioavailability of mercury in the contaminated sediments of Ulhas Estuary, India

    Digital Repository Service at National Institute of Oceanography (India)

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

    2009-01-01

    Sequential extraction of Hg was performed in a core collected from intertidal area in Ulhas Estuary in order to characterize the downward distribution and diagenetic behavior of Hg in a polluted estuary. Concentration of total Hg ranged between 0...

  9. Effects of hydrography on the distribution of bacteria and virus in Cochin Estuary, India

    Digital Repository Service at National Institute of Oceanography (India)

    Parvathi, A.; Jasna, V.; Jina, S.; Jayalakshmy, K.V.; Lallu, K.R.; Madhu, N.V.; Muraleedharan, K.R.; NaveenKumar, K.R.; Balachandran, K.K.

    2015-01-01

    ) in the estuary. The variation in the viral to bacterial ratio (3–22) indicated marked seasonality. Statistical analysis showed bacteria as a major factor controlling the distribution of viruses (60 % variability) in Cochin estuary (CE...

  10. Early Cambrian sipunculan worms from southwest China.

    Science.gov (United States)

    Huang, Di-Ying; Chen, Jun-Yuan; Vannier, Jean; Saiz Salinas, J I

    2004-08-22

    We report the discovery of sipunculan worms from the Lower Cambrian Maotianshan Shale, near Kunming (southwest China). Their sipunculan identity is evidenced by the general morphology of the animals (sausage-shaped body with a slender retractable introvert and a wider trunk) and by other features, both external (e.g. perioral crown of tentacles, and hooks, papillae and wrinkle rings on the body surface) and internal (U-shaped gut, and the anus opening near the introvert-trunk junction). The three fossil forms (Archaeogolfingia caudata gen. et sp. nov., Cambrosipunculus tentaculatus gen. et sp. nov. and Cambrosipunculus sp.) have striking similarities to modern sipunculans, especially the Golfingiidae to which their evolutionary relationships are discussed. This study suggests that most typical features of extant sipunculans have undergone only limited changes since the Early Cambrian, thus indicating a possible evolutionary stasis over the past 520 Myr. PMID:15306286

  11. Generation of overtides and compound tides in Amazon estuary

    Science.gov (United States)

    Gallo, Marcos Nicolás; Vinzon, Susana Beatriz

    2005-12-01

    Tidal propagation in estuaries is affected by friction and fresh water discharge, besides changes in the depth and morphology of the channel. Main distortions imply variations in the mean water level and asymmetry. Tidal asymmetry can be important as a mechanism for sediment accumulation and turbidity maximum formation in estuaries, while mean water level changes can affect navigation depths. Data from several gauges stations from the Amazon estuary and the adjacent coast were analyzed and a 2DH hydrodynamic model was configured in a domain covering the continental shelf up to the last section of the river where the tidal signature is observed. Based on data, theoretical and numerical results, the various influences in the generation of estuarine harmonics are presented, including that of fresh water discharge. It is shown that the main overtide, M4, derived from the most important astronomic component in the Amazon estuary, M2, is responsible for the tidal wave asymmetry. This harmonic has its maximum amplitude at the mouth, where minimum depths are found, and then decreases while tide propagates inside the estuary. Also, the numerical results show that the discharge does not affect water level asymmetry; however, the Amazon river discharge plays an important role in the behavior of the horizontal tide. The main compound tide in Amazon estuary, Msf, generated from the combination of the M2 and S2, can be strong enough to provoke neap low waters lower than spring ones. The results show this component increasing while going upstream in the estuary, reaching a maximum and then slightly decaying.

  12. The unexpected occurrence of late Sardina pilchardus (Walbaum, 1792) (Osteichthyes: Clupeidae) larvae in a temperate estuary

    OpenAIRE

    Morais, P; Faria, Ana Margarida da Silva; Chícharo, Alexandra; Chícharo, Luís

    2009-01-01

    The presence of sardine larval stages inside estuaries has generally been regarded as accidental and restricted to the lower part of estuaries. Sampling done with a zooplankton net in the Guadiana estuary corroborated this hypothesis. Late sardine larvae (32.8 ± 2.0 mm) were, however, unexpectedly collected with an otter trawl, 14 km upstream from the mouth of the estuary. Thus, this work intends to: (1) discriminate and compare the abiotic characteristics of the sites where maximum ...

  13. Sub-tidal water-level oscillations in the Mandovi estuary, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Shetye, S.R.; Vijith, V.

    2013-01-01

    Using water-level data collected at six locations during March–April 2003 in the main channel of the Mandovi estuary, one of the 50 odd estuaries on the west coast of India, we describe the nature of variability of water level in the estuary...

  14. Dynamics of intertidal flats in the Loire estuary

    Science.gov (United States)

    Kervella, Stephane; Sottolichio, Aldo; Bertier, Christine

    2014-05-01

    Tidal flats form at the edges of many tidal estuaries, and are found in broad climatic regions. Their evolution plays a fundamental role in maintaining the morphodynamic equilibrium of an estuary. The Loire estuary is one of the largest macrotidal systems of the french atlantic coast. Since 200 years, its geometry has been drastically modified through channeling, deepening, embanking, infilling of secondary channels, etc. These works altered many intertidal areas. In the recent years, efforts for the rectification of the morphology have been made in order to restore the ecology of the estuary. In this context, it is crucial to better understand the dynamics of intertidal flats, still poorly understood in this estuary. The aim of this work is to analyse a series of original observations conducted for the first time in two intertidal flats of the central Lore estuary between 2008 and 2010. The tidal flats are situated in the northern bank, at 12 and 17 km upstream from the mouth respectively. Six Altus altimeters were deployed at two cross shore transects, measuring continuously and at a high-frequency bed altimetry and water level, providing information on tide and waves. At the semi-diurnal tidal scale, the surficial sediment of intertidal flats is permanently mobilized. Altimetry variations are low, and their amplitude varies as a function of tides and river flow. At the scale of several months, the sedimentation is controlled by the position of the turbidity maximum (and therefore by the river flow) and also by the tidal amplitude. During low river flow periods, altimetry variations are only due to tidal cycles. During decaying tides, suspended sediment settle mainly on the lower part of the tidal flats, forming fluid mud layers of several cm thick, which can consolidate rapidly; under rising tides, the increasing of tidal currents promotes erosion. During periods of high river flow, the turbidity maximum shifts to the lower estuary. The higher suspended sediment concentration increases deposition and erosion rates, especially in the lower parts of the flats, where continuous sedimentary accretion is favoured by the proximity of the channel. During this period, reinforcement of current veolocities limits deposition in the central and high portion of the flats, where erosion is enhanced. The first rivers floods remove fluid mud in the upper estuary, previously deposited during the dry season, which is transported seawards. The transported suspended sediment settles massively in the lower parts of the flats and in the channels. The deposited mud is eroded a few days later. These results provide useful information to better understand the dynamics of the Loire estuary, as well as they give in situ data to be compared with numerical modelling.

  15. Long-term morphodynamic evolution of estuaries: An inverse problem

    Science.gov (United States)

    Karunarathna, Harshinie; Reeve, Dominic; Spivack, Mark

    2008-04-01

    A new technique for predicting long-term variations in estuary morphology is developed using a morphological evolution equation that isolates diffusive and non-diffusive processes in estuaries. The contribution from non-diffusive processes to the morphological changes of the estuary is incorporated in the governing equation by a source function. The source function is derived by solving an inverse problem using historic survey data of the Humber estuary, UK covering a period of 150 years. Source functions derived for the consecutive pairs of bathymetry surveys show a significant structure persistent throughout the entire data set. Large scale features such as tidal channels, tidal flats and linear banks in the outer estuary are persistently visible in the source function. Empirical Orthogonal Function (EOF) analysis is used to analyse the spatial and temporal variation in the source function. The first spatial eigenfunction which corresponds to the time-mean value of the source function captures over 92% of the mean square of the data. Over 65% of the data variance is captured by the first six eigenfunctions. The first temporal eigenfunction which corresponds to the mean value of the source function is almost constant as expected.

  16. Use of marine space by Black-browed albatrosses during the non-breeding season in the Southwest Atlantic Ocean

    Science.gov (United States)

    Copello, Sofía; Seco Pon, Juan Pablo; Favero, Marco

    2013-05-01

    Marine birds like albatrosses have shown a profound deterioration of their conservation status in recent years. The Black-browed albatross (Thalassarche melanophris) is the most abundant threatened albatross species in the Southwest Atlantic continental shelf. Declines in their breeding populations have been largely attributed to the impact of incidental mortality in fisheries. Data on at-sea distribution for the species during breeding is abundant, but movements of individuals during winter are poorly known. Here, we investigate the at-sea distribution of Black-browed albatrosses during the non-breeding seasons 2011 and 2012. Eleven adult individuals were captured at-sea and equipped with satellite tags. Distribution of tracked Black-browed albatrosses was mostly restricted to waters within the continental shelf of Argentina, Uruguay and southern Brazil; from 29° to 51°S. Two large marine areas, comprising the ca. 90% of the core area (50% utilization distribution) were identified; one from the mouth of Rio de la Plata toward the E and SE reaching the shelfbreak, and another in El Rincón estuary and waters to the South. Tracked birds were distributed over nine oceanographic regimes in the SW Atlantic continental shelf, spending between 5 and 34% of their time at sea in marine fronts of high productivity such as Río de la Plata, Los Patos lagoon estuary front, the shelfbreak and the mixed front. The identified core areas could be considered as proxy indicators of priority areas at the time of implementing conservation measures for the species. The analysis of overlapping with fisheries on the Argentinean Continental Shelf will provide further insights about critical areas where those measures should be more stringent.

  17. 2006 Southwest Florida Water Management District (SWFWMD) Lidar: North District

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is one component of a digital terrain model (DTM) for the Southwest Florida Water Management District's FY2006 Digital Orthophoto (B089) and LiDAR...

  18. Alluvial basin statistics of the Southwest Principal Aquifers (SWPA) study.

    U.S. Geological Survey, Department of the Interior — SWPA_alvbsn is a vector dataset of alluvial-fill basin statistics for the Southwest United States. Statistics for each basin include physical details such as area,...

  19. 7 CFR 1126.2 - Southwest marketing area.

    Science.gov (United States)

    2010-01-01

    ...2010-01-01 2009-01-01 true Southwest marketing area. 1126.2 Section 1126.2 Agriculture...Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Milk), DEPARTMENT...

  20. Benthic fauna of southwest and southeast coasts of India

    Digital Repository Service at National Institute of Oceanography (India)

    Devi, K.S.; Sheba, P.; Balasubramanian, T.; Venugopal, P.; Sankaranarayanan, V.N.

    1999-01-01

    Benthos, sediments characteristics and organic matter content were studied along southwest and southeast coasts of India. Number of groups/species varied with the stations and also with the depths. Population density was very low in southeast coast...

  1. Bees in the Southwest Pacific: Origins, diversity and conservation

    OpenAIRE

    Groom, Scott; Schwarz, Michael

    2011-01-01

    Bee diversity of the Southwest Pacific has been reported as depauperate despite the otherwise rich biodiversity and complex geological history for this region. However, due to a lack of bee-specific sampling, there is potential for higher bee diversity than previous studies suggest. Here, we review the current literature to summarise the extant diversity for each of the main island groups, the likely passages of species dispersal, and outline the main threats to Southwest Pacific populations....

  2. An analysis of the trophic network of a macrotidal estuary: the Seine Estuary (Eastern Channel, Normandy, France)

    Science.gov (United States)

    Rybarczyk, Hervé; Elka??m, Bernard

    2003-12-01

    A steady state, mass balance, trophic network has been constructed to illustrate the flow of energy in the Seine Estuary by using Network Analysis and Ecopath methods. This ecosystem shows 15 compartments from primary producers to the top consumers (fish and birds). This study has been compared with other ecosystems of comparable nature located in North America (Narragansett, Chesapeake, Delaware Bays), Europe (Ems Estuary, Dublin Bay and Bay of Somme), and South Africa (Swartkops Estuary) in which analysis of trophic network has been applied with similar methods. The Seine Estuary shows values of some global parameters and indices either close to large North American bays and a South African estuary characterised by the complexity of their trophic network, or values near European bays and estuaries, or else remain typical of the Seine estuary. All of this reflects specific functioning of the Seine Estuary which can be explained by the analysis of the dominant food web. In the upstream sector an important pelagic food web was found correlated with highest primary production, especially planktonic, which is rapidly consumed by an abundant zooplankton and suprabenthos (Mysidacae and Decapoda Crustacea). This reveals the dominant consumer role of this sector. The external fluvial inputs (277.80 gC m -2 y -1) are transferred to the downstream sector which produces the major export (548.43 gC m -2 y -1), in parallel with the low consumption and efficiency of dominant benthos component from its bentho-pelagic food web. This reflects the dominant exporter role of this sector. In the Seine Estuary low values of detritivory index D/ H (2.52), recycling index FCI (16.1%) and connectance (0.24) were found associated with high values of P/ B ratio (38.2%), sum of exports (548.43 gC m -2 y -1) and the great difference between ratio of ascendency to capacity development A/ C and internal ratio Ai/ Ci. This shows the lack of a dominant resource as in Delaware Bay, that the state of development is different from a mature ecosystem, and the dependance on external connections similar to the Bay of Somme, another ecosystem of Eastern Channel, France.

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

    Science.gov (United States)

    Pye, Kenneth; Blott, Simon J.

    2014-10-01

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

  4. Delaware Estuary situation reports. Emergency response: How do emergency management officials address disasters in the Delaware Estuary

    International Nuclear Information System (INIS)

    From hurricanes and other natural threats to oil spills and other manmade emergencies, the Delaware Estuary has experienced a variety of disasters over the years. The toll that these events take on the estuary and those who live on its shores depends largely upon the degree of emergency preparedness, speed of response, and effectiveness of recovery operations. In Emergency Response: How Do Emergency Management Officials Address Disasters in the Delaware Estuary, the latest addition to its Delaware Estuary Situation Report series, the University of Delaware Sea Grant College Program defines emergency management; examines the roles that the Coast Guard, Army Corps of Engineers, and Environmental Protection Agency play in an emergency; and reviews how each of these federal agencies operated during an actual disaster--the 1985 Grand Eagle oil spill. The report was written by Dr. Richard T. Sylves, a professor of political science at the University of Delaware. Sylves has been studying emergency management for the past 15 years, with special emphasis on oil spill preparedness and response in the Mid-Atlantic Region. The Delaware Estuary Situation Report is 12 pages long and contains maps and photographs, as well as a detailed account of response and recovery operations undertaken during the Grand Eagle oil spill. A comparison of the 1985 Grand Eagle spill and the 1989 Presidente Rivera spill also is included

  5. Thermal discharge effects on dissolved oxygen in an urban estuary

    International Nuclear Information System (INIS)

    As part of the permitting process for power generation plant repowering, the impact of once-through cooling to estuary dissolved oxygen concentration was examined. This included field investigation of temperature and dissolved oxygen concentration with depth at various places in the estuary under different plant operating conditions, statistical analysis of the resulting data, calibration of a water quality model to the data set, and use of the model to predict the impact of the repowered facility under drought conditions. It was concluded that the once-through cooling operation had a positive impact on estuary dissolved oxygen by its destratification of the water column and its introduction of dissolve oxygen into the effluent by turbulent mixing

  6. Waterfowl migration and distribution in North West estuaries. V. 2

    International Nuclear Information System (INIS)

    Waterfowl populations may be affected by the proposed tidal barrage across the Mersey. A study was performed with three objectives: (1) to evaluate the patterns of usage of the intertidal flats of the Mersey estuary by waders and wildfowl and to establish which are the preferred areas; (2) to identify the places of origin and movement patterns of the populations of waders and wildfowl that visit the Mersey estuary; and (3) to evaluate evidence regarding the capacity of British estuaries to absorb waders and wildfowl populations which might be displaced by a Mersey Barrage. The text and tables of results of this study have already been presented in Volume 1. Volume 2 contains the figures describing the results (U.K)

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

    International Nuclear Information System (INIS)

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

  8. Attenuation of rare earth elements in a boreal estuary

    Science.gov (United States)

    Åström, Mats E.; Österholm, Peter; Gustafsson, Jon Petter; Nystrand, Miriam; Peltola, Pasi; Nordmyr, Linda; Boman, Anton

    2012-11-01

    This study focuses on attenuation of rare earth elements (REE) when a boreal creek, acidified and loaded with REE and other metals as a result of wetland drainage, empties into a brackish-water estuary (salinity Visual MINTEQ version 3.0 and the Stockholm Humic Model after revision and updating, predicted that the dissolved (<0.45 ?m) REE pool in the estuary is bound almost entirely to humic substances. Acid sulphate soils, the source of the REE and other metals in the creek water, are widespread on coastal plains worldwide and therefore the REE attenuation patterns and mechanisms identified in the studied estuary are relevant for recognition of similar geochemical processes and conditions in a variety of coastal locations.

  9. Southwest Region Experiment Station - Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Rosenthal, A

    2011-08-19

    Southwest Technology Development Institute (SWTDI), an independent, university-based research institute, has been the operator of the Southwest Region Photovoltaic Experiment Station (SWRES) for almost 30 years. The overarching mission of SWTDI is to position PV systems and solar technologies to become cost-effective, major sources of energy for the United States. Embedded in SWTDI's general mission has been the more-focused mission of the SWRES: to provide value added technical support to the DOE Solar Energy Technologies Program (SETP) to effectively and efficiently meet the R&D needs and targets specified in the SETP Multi-Year Technical Plan. : The DOE/SETP goals of growing U.S. PV manufacturing into giga-watt capacities and seeing tera-watt-hours of solar energy production in the U.S. require an infrastructure that is under development. The staff of the SWRES has supported DOE/SETP through a coherent, integrated program to address infrastructural needs inhibiting wide-scale PV deployment in three major technical categories: specialized engineering services, workforce development, and deployment facilitation. The SWRES contract underwent three major revisions during its five year period-of- performance, but all tasks and deliverables fell within the following task areas: Task 1: PV Systems Assistance Center 1. Develop a Comprehensive multi-year plan 2. Provide technical workforce development materials and workshops for PV stakeholder groups including university, professional installers, inspectors, state energy offices, Federal agencies 3. Serve on the NABCEP exam committee 4. Provide on-demand technical PV system design reviews for U.S. PV stakeholders 5. Provide PV system field testing and instrumentation, technical outreach (including extensive support for the DOE Market Transformation program) Task 2: Design-for-Manufacture PV Systems 1. Develop and install 18 kW parking carport (cost share) and PV-thermal carport (Albuquerque) deriving and publishing lessons learned Task 3: PV Codes and Standards 1. Serve as the national lead for development and preparation of all proposals (related to PV) to the National Electrical Code 2. Participate in the Standards Technical Panels for modules (UL1703) and inverters (UL1741) Task 4: Assess Inverter Long Term Reliability 1. Install and monitor identical inverters at SWRES and SERES 2. Operate and monitor all inverters for 5 years, characterizing all failures and performance trends Task 5: Test and Evaluation Support for Solar America Initiative 1. Provide test and evaluation services to the National Laboratories for stage gate and progress measurements of SAI TPP winners

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

    Digital Repository Service at National Institute of Oceanography (India)

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

    2011-01-01

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

  11. Radium isotopes in the Orinoco estuary and Eastern Caribbean Sea

    International Nuclear Information System (INIS)

    Radium isotopes provide a means of identifying the source of freshened waters in the ocean and determining the time elapsed since these waters were in the estuary. The authors present evidence that during April, waters from the Amazon mixing zone pass within 50 km of the mouth of the Orinoco River. These Amazon waters are characterized by a lower 228Ra/226Ra activity ratio (AR) than are waters from the Orinoco at similar salinities. During autumn, the increased discharge of the Orinoco displaces the freshened Amazon waters seaward, yet the two can be distinguished clearly. Within the Caribbean Sea, waters of Orinoco origin carry a characteristic radium signature including excess activities of 224Ra. This isotope may be used to estimate the time elapsed since the waters were removed from contact with sediments. Current speeds based on 224Ra dating ranged from 15 to 33 cm/s during April. The radium isotopes also provide an assessment of sediment mixing in the estuary. During low discharge (April), considerable mixing of older sediment by physical or biological processes or dredging maintained high activities of 228Ra in the estuary and produced the highest 228Ra/226Ra AR's yet measured in any estuary. During high discharge (September), a large fraction of the 228Ra was derived from desorption from fresh sediment rather than mixing of older sediments. Activities of 224Ra wediments. Activities of 224Ra were high in the estuary during both high and low discharge, indicating that considerable mixing of recently introduced sediment must occur during each period. During April, 224Ra and 228Ra activities in the water were about equal, indicating that most of the sediment being resuspended had been stored in the estuary long enough to reestablish radioactive equilibrium in the 232Th decay series (i.e., 20 years). 19 refs., 11 figs., 3 tabs

  12. Mud transport in the Microtidal San Jacinto Estuary

    Science.gov (United States)

    Salehi, M.

    2013-12-01

    The overall objective of this research is to better understand the sediment transport processes in the microtidal San Jacinto Estuary (near Houston, TX) under variable hydrologic conditions. A numerical modeling approach is selected to answer the main question of; how will changes in freshwater input change the sedimentation pattern of the region? In this computational work, no new numerical method or code is developed, but rather an existing technology (MIKE 3D developed by DHI) is used to build a virtual San Jacinto Estuary laboratory where boundary conditions could be applied and altered to the domain to observe the general functional response of the system. Two synthetic freshwater inflows, simulating dry and wet conditions, were used in the numerical modeling experiments. Simulations showed that change in freshwater inflow has major impact on the salinity magnitude within the estuary. In dry conditions, the 5 ppt isohaline traveled all the way upstream of Morgans Point, almost to the confluence of San Jacinto River with Buffalo Bayou. During the extreme wet weather conditions, the 5 ppt isohaline of the surface water was pushed almost as far as Galveston Island. Overall erosion and deposition pattern showed little change between extreme dry and wet years. In general, part of the shallow areas experienced erosion whereas deeper parts of the estuary were under deposition. High freshwater inflow caused around 30% higher deposition in some parts of the channel compared with the low freshwater. Furthermore, examining the mass balance within the whole San Jacinto Estuary showed that around 28% of the input sediment was flushed out during the wet season. But in dry season, not only no sediment left the domain but also it received around 17% of the total available sediment within the estuary from the shelf.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-02-05

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

  14. Southwest Watershed Research Center Data Access Project

    Science.gov (United States)

    Nichols, M. H.; Anson, E.

    2008-05-01

    Hydrologic data, including rainfall and runoff data, have been collected on experimental watersheds operated by the U.S. Department of Agriculture Agricultural Research Service (USDA-ARS) in southern Arizona since the 1950s. These data are of national and international importance and make up one of the most comprehensive semiarid watershed data sets in the world. The USDA-ARS Southwest Watershed Research Center has recently developed an electronic data processing system that includes an online interface (http://tucson.ars.ag.gov/dap) to provide public access to the data. The goal of the system is to promote analyses and interpretations of historic and current data by improving data access. Data are collected from sensors in the field and are transmitted to computers in the office. The data are then processed, quality checked, and made available to users via the Internet. The publicly accessible part of the system consists of an interactive Web site, which provides an interface to the data, and a relational database, which is used to process, store, and manage data. The system was released to the public in October 2003, and since that time the online data access Web site has received more than 4500 visitors.

  15. The Nubian Aquifer in Southwest Egypt

    Science.gov (United States)

    Robinson, C. A.; Werwer, A.; El-Baz, F.; El-Shazly, M.; Fritch, T.; Kusky, T.

    2007-02-01

    Synthetic Aperture Radar (SAR) images, and topographic and groundwater data are used to understand heterogeneities of the Nubian Aquifer between 20 24.5°N and 25 32°E in southwest Egypt. New fluvial and structural interpretations emphasize that the desert landscape was produced by fluvial action, including newly mapped alluvial fans. In central locations, braided channels are spatially aligned with a NE structural trend, suggesting preferential water flow paths that are consistent with the local direction of groundwater flow. The alluvial fans and structurally enclosed channels coincide with gentle slopes and optimal recharge conditions (1 5%) derived from the new Shuttle Radar Topographic Mission (SRTM) slope map, indicating that these areas have high groundwater potential. The SAR interpretations are correlated with anomalies observed in groundwater data from 383 wells. Results suggest a relationship between the spatial organization of fluvial and structural features and the occurrence of low-salinity groundwater. Low-salinity water exists adjacent to the alluvial fans and in SW reaches of the structurally enclosed channels. Wells in the vicinity of structures contain low-salinity water, emphasizing that knowledge of structural features is essential to understand groundwater flow paths. The new approach is cost effective and noninvasive and can be applied throughout the eastern Sahara to assist in resource management decisions and support the much needed agricultural expansion.

  16. Southwest Washington coastal erosion workshop report 2000

    Science.gov (United States)

    Gelfenbaum, Guy, (Edited By); Kaminsky, George M.

    2002-01-01

    This report is a compilation of abstracts that correspond to oral presentations and posters presented at the fifth principal investigators workshop of the Southwest Washington Coastal Erosion Study. The workshop was held November 15 - 17, 2000 at the Department of Ecology headquarters building in Olympia, WA. For the fourth consecutive year in November, the workshop convened the entire multi-disciplinary group of scientists and engineers working on the Study or on related projects within the Columbia River littoral cell (CRLC) (Figures 1 and 2). The workshop participants are listed in the List of Attendees section towards the end of this report. The purpose of this workshop was to bring all Study investigators and associated engineers and scientists together to discuss recent work, ongoing tasks, and future research plans in the CRLC. Investigators were asked to present recent data, preliminary interpretations, and research results to invoke discussion and correlation with parallel scientific efforts. The abstracts compiled in this report represent a wealth of information on the CRLC, but because much of the work is in progress, the reader is advised that the information provided herein is preliminary and subject to change.

  17. Historic developments in macrozoobenthos of the Rhine Meuse estuary: From a tidal inlet to a freshwater lake

    Science.gov (United States)

    Wijnhoven, S.; Sistermans, W.; Hummel, H.

    2008-01-01

    Water works during the 1960s and 1970s changed the northern part of the Rhine-Meuse estuary in the south-west of the Netherlands into a freshwater lake, from west to east divided into three basins called the Haringvliet, the Hollands Diep and the Biesbosch. Concurrently water quality parameters (e.g. nutrients and pollutants) changed drastically during the last 50 years. This study combines macrozoobenthic monitoring data from the region from 1960 to 2001 with trends in abiotic parameters to evaluate historic developments of the communities, including densities, species numbers and diversity, and assess future developments as a first step to a rehabilitation of the estuary as planned for January 01, 2008. During the 1960s, the macrozoobenthic densities of Oligochaeta and/or Polychaeta dominated communities increased with a gradual decrease of saltwater intrusion and salinity variability. The first years after the basins became stagnant, the species numbers per sample and the Shannon diversity were high due to the coexistence of salt and freshwater species. An increase in nutrient and pollutant loads led to a decrease in the macrozoobenthos densities. As water and sediment quality gradually improved, nowadays the former estuary contains high diversity and high density macrozoobenthic communities, whereas Oligochaeta and/or Polychaeta were dominant in the 1960s, and Bivalvia and Gastropoda were more abundant during the 1970s. Macrozoobenthic communities moved from the east to west with a time-lag, which may primarily be attributed to changing salinities, salinity variances and oxygen levels. Therefore, the current communities of the Haringvliet show similarities with the communities that occurred already during the 1960s in the Biesbosch. This study shows the value of macrozoobenthos monitoring data over longer periods. The possible impact of a new saltwater inlet in the west of the Haringvliet, allowing in the near future saltwater to enter 11.5 km eastward, yet alternated by frequent flushing with freshwater to ascertain that the salt intrusion does not reach further, on the development of the macrozoobentic communities is discussed.

  18. Difference in the crab fauna of mangrove areas at a southwest Florida and a northeast Australia location: Implications for leaf litter processing

    Science.gov (United States)

    McIvor, C.C.; Smith, T. J., III

    1995-01-01

    Existing paradigms suggest that mangrove leaf litter is processed primarily via the detrital pathway in forests in the Caribbean biogeographic realm whereas herbivorous crabs are relatively more important litter processors in the Indo-West Pacific. To test this hypothesis, we used pitfall traps to collect intertidal crabs to characterize the crab fauna in a mangrove estuary in southwest Florida. We also tethered mangrove leaves to determine if herbivorous crabs are major leaf consumers there. We compared the results with previously published data collected in an analogous manner from forests in northeastern Australia. The crab fauna in Rookery Bay, Florida, is dominated by carnivorous xanthid and deposit-feeding ocypodid crabs whereas that of the Murray River in northeastern Australia is dominated by herbivorous grapsid crabs. No leaves tethered at five sites in the forests in Southwest Florida were taken by crabs. This contrasts greatly with reported values of leaf removal by crabs in Australian forests of 28-79% of the leaves reaching the forest floor. These differences in the faunal assemblages and in the fate of marked or tethered leaves provide preliminary support for the hypothesis that leaf litter is in fact processed in fundamentally different ways in the two biogeographic realms.

  19. Rhenium and Molybdenum in Rivers and Estuaries.

    Science.gov (United States)

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

    2004-12-01

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

  20. Forward for book entitled "Estuaries: Classification, Ecology, and Human Impacts"

    Science.gov (United States)

    The author was introduced to the science of estuaries as a graduate student in the early 1980s, studying the ecology of oyster populations in Chesapeake Bay. To undertake this research, he needed to learn not only about oyster biology, but also about the unique physical and chemi...

  1. Water and suspended sediment dynamics in Selangor River estuary

    International Nuclear Information System (INIS)

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

  2. CHEMICAL CONSTITUENTS OF AVICENNIA ALBA OF KRISHNA ESTUARY

    OpenAIRE

    Ramanjaneyulu MVV* and Venkateswara Rao

    2013-01-01

    Phytochemical investigation on the aerial roots of Avicennia alba of Krishna estuary, resulted in the isolation of four triterpenoids, Lupeol (1), taraxerol (2), betulinic acid (3)   and botulin (4). These are characterized by physical and spectral data and all are known compounds but we are reporting first time from this plant. Compound (4) was also possess antibacterial activity.

  3. Laboratory Investigations on Estuary Salinity Mixing: Preliminary Analysis

    Directory of Open Access Journals (Sweden)

    F. H. Nuryazmeen

    2014-05-01

    Full Text Available Estuaries are bodies of water along the coasts that are formed when fresh water from rivers flows into and mixes with salt water from the ocean. The estuaries serve as a habitat to some aquatic lives, including mangroves. Human-induced activities such as dredging of shipping lanes along the bottom estuarine, the disposal of industrial wastes into the water system and shoreline development influence estuarine dynamics which include mixing process. These activities might contribute to salinity changes and further adversely affect the estuarine ecosystem. In order to study at the characteristics of the mixing between salt water (estuary and freshwater (river, a preliminary investigation had been done in the laboratory. Fresh water was released from one end of the flume and overflowing at weir at the other end. Meanwhile, salt water was represented by the red dye tracer released through a weir and intruded upstream as a gravity current. The isohalines are plotted to see the salinity patterns. Besides, to examine the spatial and temporal salinity profiles along the laboratory investigations, the plotted graphs have been made. The results show that the changes in salinity level along the flume due to mixing between fresh water and salt water. This showed typical salt-wedge estuary characteristics.

  4. Isolation and Characterization of Vibrio vulnificus from Two Florida Estuaries

    OpenAIRE

    Tamplin, M.; Rodrick, G. E.; Blake, N. J.; Cuba, T.

    1982-01-01

    Vibrio vulnificus was enumerated in seawater and shellfish from two Florida estuaries at selected seasonal intervals. There were significant fluctuations in the presence and numbers of V. vulnificus. Relatively high seawater temperature and salinity favored the presence of V. vulnificus in both seawater and shellfish samples.

  5. CHEMICAL CONSTITUENTS OF AVICENNIA ALBA OF KRISHNA ESTUARY

    Directory of Open Access Journals (Sweden)

    Ramanjaneyulu MVV* and Venkateswara Rao

    2013-12-01

    Full Text Available Phytochemical investigation on the aerial roots of Avicennia alba of Krishna estuary, resulted in the isolation of four triterpenoids, Lupeol (1, taraxerol (2, betulinic acid (3   and botulin (4. These are characterized by physical and spectral data and all are known compounds but we are reporting first time from this plant. Compound (4 was also possess antibacterial activity.

  6. ASSESSING THE ECOLOGICAL CONDITION OF VERACRUZ, MEXICO ESTUARIES

    Science.gov (United States)

    Macauley, John, Hector A. Vasquez, George Craven and P. Thomas Heitmuller. In press. Assessing the Ecological Condition of Veracruz, Mexico Estuaries (Abstract). To be presented at the EPA Science Forum: Healthy Communities and Ecosystems, 1-3 June 2004, Washington, DC. 1 p. (ERL...

  7. Maturation of Metapenaeus moyebi (Kishinouye) in Goa estuaries

    Digital Repository Service at National Institute of Oceanography (India)

    Nair, S.R.S.; Achuthankutty, C.T; Parulekar, A.H.

    1993-01-01

    study point it formed as much as 30.77% of the stake net fishery. Also, 35.1% of the males caught were with fully developed spermatophores. Interestingly, females in maturity stages 3 and 4 were caught from one estuary. Our data shows that this species...

  8. Burrowing shrimp as foundation species in NE Pacific estuaries

    Science.gov (United States)

    My talk will be about the my research to characterize the role that burrowing shrimp play as foundation/engineering species in Pacific NW estuaries. My research has focused on measuring the abundance & distribution of two species (ghost shrimp & mud shrimp) at ecosystem scales, ...

  9. Sediment transport investigations in Hugli estuary using radiotracer technique

    International Nuclear Information System (INIS)

    This paper describes sediment transport investigations carried out at two different locations in Hugli estuary along the shipping channel leading to Haldia Dock Complex of the Kolkata Port Trust, Kolkata. The objectives of these investigations were to evaluate the suitability of the proposed dumping sites for optimizing the dredging operation and implementing the recommendations of the River Regulatory Measures, Kolkata Port Trust, Kolkata

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

    Digital Repository Service at National Institute of Oceanography (India)

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

    2012-01-01

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

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

    Digital Repository Service at National Institute of Oceanography (India)

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

    1991-01-01

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

  12. Behaviour of aluminium, silicon and iron in Tapi Estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Sharma, P.; Zingde, M.D.

    1995-01-01

    of pH, dissolved oxygen, NO sub(3) sup(-) -N and NH sub(4) sup(+) -N which were also suggestive of some biogenic removal of dissolved Fe. In the estuary however, dissolved Fe was randomly distributed and poorly correlated with chlorinity as well as pH....

  13. Time-dependent stratification in the Gauthami-Godavari Estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, T.V.N.

    2001-01-01

    associated with the density driven flow. Destratification occurs around the high water slacks in the lower reaches fairly close to the mouth of the estuary. The variations in the fields of mass will strongly affect the response of the velocity field...

  14. The dynamics of a frictionally-dominated Amazonian estuary

    Scientific Electronic Library Online (English)

    Nils Edvin, Asp; Carlos Augusto França, Schettini; Eduardo, Siegle; Marcio Sousa da, Silva; Roney Nonato Reis de, Brito.

    2012-09-01

    Full Text Available A hidrodinâmica, morfologia e sedimentologia do estuário do Taperaçu foram investigadas. Este é um entre vários estuários do litoral amazônico que integram a maior extensão contínua de manguezais do mundo, apresentando uma descarga de água doce muito reduzida, atípica para a região. Os resultados re [...] velam grandes bancos arenosos que ocupam em grande parte a porção central do estuário. Areias muito finas e bem selecionadas de origem marinha prevalecem. Fases de enchente mais curtas, com velocidades de corrente substancialmente mais altas, são observadas na porção superior do estuário, como esperado para um estuário raso e dominado por fricção. Por outro lado, uma vazante mais intensa poderia ocorrer como resultado de grandes áreas de manguezais associadas e intenso preenchimento estuarino, sendo que ambas as condições são observadas no Taperaçu. Neste caso, a prevalência da enchente parece estar associada à ausência de uma descarga fluvial efetiva. Além disso, alguns canais de maré conectam o Taperaçu com seu vizinho estuário do Caeté, o que contribuiria para o domínio de enchente. Como um todo, os resultados demonstram uma complexa interação de aspectos de configuração (fricção, drenagem fluvial, conexões com estuários vizinhos, preenchimento e grandes áreas intermareais) na determinação dos padrões hidrodinâmicos, contribuindo para o entendimento dos estuários da região amazônica. Abstract in english The hydrodynamics, morphology and sedimentology of the Taperaçu estuary were investigated. This is one of several estuaries located within the largest mangrove fringe in the world, bordering the Amazon region, subject to a macrotidal regime and regionally atypical negligible fresh water supply. The [...] results reveal widespread sand banks that occupy the central portion of the estuarine cross-section. Well-sorted very fine sandy sediments of marine origin prevail. Shorter flood phases, with substantially higher current velocities, were observed in the upper sector of Taperaçu, as expected for a shallow, friction-dominated estuary. However, ebb domination can be expected for estuaries with large associated mangrove areas and substantial estuarine infilling, both of which situations occur on the Taperaçu. The tidal asymmetry favoring flood currents could be the result of the absence of an effective fluvial discharge. Furthermore, it was observed that the Taperaçu is connected by tidal creeks to the neighboring Caeté estuary, allowing a stronger flux during the flood and intensifying the higher flood currents. As a whole, the results have shown a complex interaction of morphological aspects (friction, fluvial drainage, connections with neighbor estuaries, infilling and large storage area) in determining hydrodynamic patterns, thus improving the understanding of Amazon estuaries.

  15. The dynamics of a frictionally-dominated Amazonian estuary

    Directory of Open Access Journals (Sweden)

    Nils Edvin Asp

    2012-09-01

    Full Text Available The hydrodynamics, morphology and sedimentology of the Taperaçu estuary were investigated. This is one of several estuaries located within the largest mangrove fringe in the world, bordering the Amazon region, subject to a macrotidal regime and regionally atypical negligible fresh water supply. The results reveal widespread sand banks that occupy the central portion of the estuarine cross-section. Well-sorted very fine sandy sediments of marine origin prevail. Shorter flood phases, with substantially higher current velocities, were observed in the upper sector of Taperaçu, as expected for a shallow, friction-dominated estuary. However, ebb domination can be expected for estuaries with large associated mangrove areas and substantial estuarine infilling, both of which situations occur on the Taperaçu. The tidal asymmetry favoring flood currents could be the result of the absence of an effective fluvial discharge. Furthermore, it was observed that the Taperaçu is connected by tidal creeks to the neighboring Caeté estuary, allowing a stronger flux during the flood and intensifying the higher flood currents. As a whole, the results have shown a complex interaction of morphological aspects (friction, fluvial drainage, connections with neighbor estuaries, infilling and large storage area in determining hydrodynamic patterns, thus improving the understanding of Amazon estuaries.A hidrodinâmica, morfologia e sedimentologia do estuário do Taperaçu foram investigadas. Este é um entre vários estuários do litoral amazônico que integram a maior extensão contínua de manguezais do mundo, apresentando uma descarga de água doce muito reduzida, atípica para a região. Os resultados revelam grandes bancos arenosos que ocupam em grande parte a porção central do estuário. Areias muito finas e bem selecionadas de origem marinha prevalecem. Fases de enchente mais curtas, com velocidades de corrente substancialmente mais altas, são observadas na porção superior do estuário, como esperado para um estuário raso e dominado por fricção. Por outro lado, uma vazante mais intensa poderia ocorrer como resultado de grandes áreas de manguezais associadas e intenso preenchimento estuarino, sendo que ambas as condições são observadas no Taperaçu. Neste caso, a prevalência da enchente parece estar associada à ausência de uma descarga fluvial efetiva. Além disso, alguns canais de maré conectam o Taperaçu com seu vizinho estuário do Caeté, o que contribuiria para o domínio de enchente. Como um todo, os resultados demonstram uma complexa interação de aspectos de configuração (fricção, drenagem fluvial, conexões com estuários vizinhos, preenchimento e grandes áreas intermareais na determinação dos padrões hidrodinâmicos, contribuindo para o entendimento dos estuários da região amazônica.

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

    Science.gov (United States)

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

    2013-11-01

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

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

    Science.gov (United States)

    Yu, Yingying; Zhang, Hong; Lemckert, Charles

    2014-11-01

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

  18. Holocene estuary development in the Algarve Region (Southern Portugal)

    Science.gov (United States)

    Schneider, Heike; Höfer, Dana; Trog, Carmen; Hempel, Rita; Daut, Gerhard; Mäusbacher, Roland

    2010-05-01

    Former coastal estuaries in the Algarve region of South Portugal are used for reconstruction coastal evolution since first marine transgression processes at about 8.000 years before. The sediments of these archives allow high resolution analyses of geochemical and palynological signals. Drillings in different lagoons of the Algarve region contain the sequences from the fluvial sediments during the early Holocene, marine transgression facies during the middle Holocene and the marine/fluvial sediment deposits until present. The results of the sedimentological, geochemical and palynological analyses show that each estuary developed differently, depending on the morphology of the paleovalley, environmental conditions and especially the influence of the sea and the formation of barrier systems. The estuaries were flooded between 7500 and 5500 cal a BP by sea level rise and were almost completely filled by sediment by the beginning of the Roman occupation (226 y BC / 2176 cal a BP). A clear change in sedimentological processes is evident in the estuaries between 5500 and 3000 cal a BP and is interpreted as a result of high energy events such as storms or tsunamis (Schneider et al. 2009, Hilbich et al. 2008 ). Palynological as well as archaeological investigations show distinct anthropogenic influences since 3500 cal. BP by increasing values in maquies, cereals and open land communities. References Hilbich, C., Mügler, I., Daut, G., Frenzel, P., van der Borg, K., Mäusbacher, R. (2008): Reconstruction of the depositional history of the former coastal lagoon of Vilamoura (Algarve, Portugal): A sedimentological, microfaunal and geophysical approach.- Journal of Coastal Research 24(2B), 83-91. Schneider, H., Höfer, D., Trog, C., Busch, S., Schneider, M., Baade, J., Daut, G. & R. Mäusbacher (2009): Holocene estuary development in the Algarve Region (Southern Portugal) - A reconstruction of sedimentological and ecological evolution. - Quaternary International (In Press, Accepted Manuscript, Available online 24 October 2009).

  19. Residential system designs for the northeast and southwest

    Energy Technology Data Exchange (ETDEWEB)

    Russell, M. C.

    1980-01-01

    The development of residential photovoltaic power systems as part of the United States Department of Energy photovoltaic program will begin in FY-80. Prototype residential systems for heating, cooling and electric power will be built and evaluated at regional Residential Experiment Stations (RES's). The first RES locations will be in the Northeast and Southwest. The most appropriate system designs for Northeast and Southwest residences have been identified in various studies. Photovoltaic collector systems will be fielded in both the Northeast and Southwest RES facilities. A utility-interactive direct current to alternating current power inverter will be used with no on-site electrical storage. Similar systems using either combined photovoltaic/thermal collectors or separate photovoltaic modules and solar thermal collectors will be fielded at the Northeast RES facility.

  20. 78 FR 9449 - Noise Exposure Map Notice, Southwest Florida International Airport, Fort Myers, FL

    Science.gov (United States)

    2013-02-08

    ...Federal Aviation Administration Noise Exposure Map Notice, Southwest Florida...announces its determination that the Noise Exposure Maps submitted by the Lee County...announces that the FAA finds that the Noise Exposure Maps submitted for Southwest...

  1. 2004 Southwest Florida Water Management District (SWFWMD) Lidar: Lake Hancock District

    National Oceanic and Atmospheric Administration, Department of Commerce — The Light Detection and Ranging (LiDAR) LAS dataset is a survey of select areas within Southwest Florida. These data were produced for the Southwest Florida Water...

  2. 2005 Southwest Florida Water Management District (SWFWMD) Lidar: Little Manatee District

    National Oceanic and Atmospheric Administration, Department of Commerce — The Light Detection and Ranging (LiDAR) LAS dataset is a survey of select areas within Southwest Florida. These data were produced for the Southwest Florida Water...

  3. Does subterranean flow initiate mud banks off the southwest coast of India?

    Digital Repository Service at National Institute of Oceanography (India)

    Balachandran, K.K.

    2004-01-01

    Coastal waters off the southwest coast of India draw special attention because of the occurrence of mud banks at certain locations during southwest monsoon period. The present study puts forward a hypothesis of a subterranean flow, which could be a...

  4. Measuring the contribution of benthic ecosystem engineering species to the ecosystem services of an estuary: A case study of burrowing shrimps in Yaquina Estuary, Oregon - April 2009

    Science.gov (United States)

    Burrowing shrimps are regarded as ecosystem engineering species in many coastal ecosystems worldwide, including numerous estuaries of the west coast of North America (Baja California to British Columbia). In estuaries of the U.S. Pacific Northwest, two species of large burrowing...

  5. Measuring the contribution of benthic ecosystem engineering species to the ecosystem services of an estuary: A case study of burrowing shrimps in Yaquina Estuary, Oregon

    Science.gov (United States)

    Burrowing shrimps are regarded as ecosystem engineering species in many coastal ecosystems worldwide, including numerous estuaries of the west coast of North America (Baja California to British Columbia). In estuaries of the U.S. Pacific Northwest, two species of large burrowing...

  6. Estuary Data Mapper: A Stand-Alone Tool for Geospatial Data Access, Visualization and Download for Estuaries and Coastal Watersheds of the United States. (UNH)

    Science.gov (United States)

    The US EPA Estuary Data Mapper (EDM; http://badger.epa.gov/rsig/edm/index.html) has been designed as a free stand-alone tool for geospatial data discovery, visualization, and data download for estuaries and their associated watersheds in the conterminous United States. EDM requi...

  7. Estuary Data Mapper: A Stand-Alone Tool for Geospatial Data Access, Visualization and Download for Estuaries and Coastal Watersheds of the United States

    Science.gov (United States)

    The US EPA Estuary Data Mapper (EDM; http://badger.epa.gov/rsig/edm/index.html) has been designed as a free stand-alone tool for geospatial data discovery, visualization, and data download for estuaries and their associated watersheds in the conterminous United States. EDM requi...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-02-20

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

  9. Circulation and suspended particulate matter transport in a tidally dominated estuary: caravelas estuary, Bahia, Brazil

    Scientific Electronic Library Online (English)

    Carlos Augusto França, Schettini; Luiz Bruner de, Miranda.

    2010-03-01

    Full Text Available A circulação e o transporte de material particulado em suspensão no Estuário de Caravelas são pesquisados. Dados quase-sinóticos hidrográficos, de correntes (velocidade e transporte de volume com ADCP) e de material particulado em suspensão, foram medidos em intervalos horários durante um ciclo semi [...] diurno de maré de sizígia, em duas seções transversais na Boca do Tomba e na Barra Velha e também em seções longitudinais na baixa-mar e na preamar. Na primeira transversal as correntes máximas de vazante (-1,50 m s-1) foram quase duas vezes mais intensas do que na seção transversal mais larga e rasa Barra Velha, (-0,80 m s-1) e as maiores velocidades das correntes de enchente foram de 0,75 m s-1 e 0,60 m s-1, respectivamente. Devido à grande intensidade das correntes de maré, nas duas seções transversais a salinidade apresentou-se fracamente estratificada, sendo classificadas com o Diagrama Estratificação-circulação do Tipo 2a (parcialmente misturada e fraca estratificação vertical) e do Tipo 1a (bem misturada). Os transportes de volume foram muito próximos, variando de -3.500 m³ s-1 a 3.100 m³ s-1, na vazante e na enchente, respectivamente, com um transporte de volume residual igual a -630 m³ s-1. A concentração do material particulado em suspensão (MPS) esteve fortemente relacionado à variação da maré, decrescendo estuário acima de 50 mg.L-1, na boca do estuário, para 10 mg.L-1 para distâncias de 9 km e 16 km nos experimentos na baixa-mar e preamar, respectivamente. O transporte residual de MPS foi estuário abaixo com uma taxa estimada em -18 ton por ciclo de maré. Abstract in english The circulation and transport of suspended particulate matter in the Caravelas Estuary are assessed. Nearly-synoptic hourly hydrographic, current (ADCP velocity and volume transport) and suspended particulate matter data were collected during a full semidiurnal spring tide, on the two transects Boca [...] do Tomba and Barra Velha and on longitudinal sections at low and high tide. On the first transect the peak ebb currents (-1.5 ms-1) were almost twice as strong as those of the wider and shallow Barra Velha inlet (-0.80 ms-1) and the peak flood currents were 0.75 and 0.60 ms-1, respectively. Due to the strong tidal currents both inlets had weak vertical salinity stratification and were classified with the Stratification-circulation Diagram as Type 2a (partially mixed-weakly stratified) and Type 1a (well mixed). Volume transports were very close, ranging from -3,500 to 3,100 m³s-1 at the ebb and flood, respectively, with a residual -630 m³s-1. The concentration of the suspended particulate matter was closely related to the tidal variation and decreased landwards from 50 mg.L-1 at the estuary mouth, to 10 mg.L-1 at distances of 9 and 16 km for the low and high tide experiments, respectively. The total residual SPM transport was out of the estuary at rates of -18 tons per tidal cycle.

  10. Circulation and suspended particulate matter transport in a tidally dominated estuary: caravelas estuary, Bahia, Brazil

    Directory of Open Access Journals (Sweden)

    Carlos Augusto França Schettini

    2010-03-01

    Full Text Available The circulation and transport of suspended particulate matter in the Caravelas Estuary are assessed. Nearly-synoptic hourly hydrographic, current (ADCP velocity and volume transport and suspended particulate matter data were collected during a full semidiurnal spring tide, on the two transects Boca do Tomba and Barra Velha and on longitudinal sections at low and high tide. On the first transect the peak ebb currents (-1.5 ms-1 were almost twice as strong as those of the wider and shallow Barra Velha inlet (-0.80 ms-1 and the peak flood currents were 0.75 and 0.60 ms-1, respectively. Due to the strong tidal currents both inlets had weak vertical salinity stratification and were classified with the Stratification-circulation Diagram as Type 2a (partially mixed-weakly stratified and Type 1a (well mixed. Volume transports were very close, ranging from -3,500 to 3,100 m³s-1 at the ebb and flood, respectively, with a residual -630 m³s-1. The concentration of the suspended particulate matter was closely related to the tidal variation and decreased landwards from 50 mg.L-1 at the estuary mouth, to 10 mg.L-1 at distances of 9 and 16 km for the low and high tide experiments, respectively. The total residual SPM transport was out of the estuary at rates of -18 tons per tidal cycle.A circulação e o transporte de material particulado em suspensão no Estuário de Caravelas são pesquisados. Dados quase-sinóticos hidrográficos, de correntes (velocidade e transporte de volume com ADCP e de material particulado em suspensão, foram medidos em intervalos horários durante um ciclo semidiurno de maré de sizígia, em duas seções transversais na Boca do Tomba e na Barra Velha e também em seções longitudinais na baixa-mar e na preamar. Na primeira transversal as correntes máximas de vazante (-1,50 m s-1 foram quase duas vezes mais intensas do que na seção transversal mais larga e rasa Barra Velha, (-0,80 m s-1 e as maiores velocidades das correntes de enchente foram de 0,75 m s-1 e 0,60 m s-1, respectivamente. Devido à grande intensidade das correntes de maré, nas duas seções transversais a salinidade apresentou-se fracamente estratificada, sendo classificadas com o Diagrama Estratificação-circulação do Tipo 2a (parcialmente misturada e fraca estratificação vertical e do Tipo 1a (bem misturada. Os transportes de volume foram muito próximos, variando de -3.500 m³ s-1 a 3.100 m³ s-1, na vazante e na enchente, respectivamente, com um transporte de volume residual igual a -630 m³ s-1. A concentração do material particulado em suspensão (MPS esteve fortemente relacionado à variação da maré, decrescendo estuário acima de 50 mg.L-1, na boca do estuário, para 10 mg.L-1 para distâncias de 9 km e 16 km nos experimentos na baixa-mar e preamar, respectivamente. O transporte residual de MPS foi estuário abaixo com uma taxa estimada em -18 ton por ciclo de maré.

  11. Why Do Some Estuaries Close: A Model of Estuary Entrance Morphodynamics.

    Science.gov (United States)

    McSweeney, S. L.; Kennedy, D. M.; Rutherfurd, I.

    2014-12-01

    Intermittently Closed/Open Coastal Lakes/Lagoons (ICOLLs) are a form of wave-dominated, microtidal estuary that experience periodic closure in times of low river flow. ICOLL entrance morphodynamics are complex due to the interaction between wave, tidal and fluvial processes. Managers invest substantial funds to artificially open ICOLLs as they flood surrounding property and infrastructure, and have poor water quality. Existing studies examine broad scale processes but do not identify the main drivers of entrance condition. In this research, the changes in entrance geomorphology were surveyed before and after artificial entrance openings in three ICOLLs in Victoria, Australia. Changes in morphology were related to continuous measures of sediment volume, water level, tide and wave energy. A six-stage quantitative phase model of entrance geomorphology and hydrodynamics is presented to illustrate the spatio-temporal variability in ICOLL entrance morphodynamics. Phases include: breakout; channel expansion with rapid outflow; open with tidal exchange; initial berm rebuilding with tidal attenuation; partial berm recovery with rising water levels; closed with perched water levels. Entrance breakout initiates incision of a pilot channel to the ocean, whereby basin water levels then decline and channel expansion as the headcut migrates landwards. Peak outflow velocities of 5 m/s-3 were recorded and channel dimensions increased over 6 hrs to 3.5 m deep and 140 m wide. When tidal, a clear semi-diurnal signal is superimposed upon an otherwise stable water level. Deep-water wave energy was transferred 1.8 km upstream of the rivermouth with bores present in the basin. Berm rebuilding occurred by littoral drift and cross-shore transport once outflow ceased and microscale bedform features, particularly antidunes, contributed to sediment progradation. Phase duration is dependant on how high the estuary was perched above mean sea level, tidal prism extent, and onshore sediment supply. High offshore wave height and frequency, in addition to littoral drift magnitude, were main drivers of closure. This study presents a predictive model of entrance morphodynamics whereby managers can determine proximity to natural closure or opening, and as a result identify whether implementing an artificial opening is worthwhile.

  12. Distinguishing resuspension and advection signals in a hypertidal estuary

    Science.gov (United States)

    Todd, David; Souza, Alex; Jago, Colin

    2015-04-01

    Terrestrial material is supplied to an estuary system by the river, while marine material is supplied by the sea. Whether the estuary acts as a trap or a bypass zone for SPM (suspended particulate matter) depends upon the properties and dynamics of both the estuary, including the tidal and residual behaviour of the currents, and the SPM, including particle sizes and settling velocities and concentration gradients, which together control the dynamics, such as the trapping efficiency, of the estuary. Whether an SPM signal is regarded as being one of resuspension or advection depends upon the area of interest, and therefore distinguishing between resuspension and advection can be complex. Material that is resuspended within the area of study is regarded as resuspension, while that which is resuspended outside, but passes through, the area of interest, is regarded as advection. The results of a measurement campaign undertaken in a hypertidal UK estuary during the pre-spring bloom February-March and post-spring bloom May-June are presented utilising a combination of acoustic and optical instruments, moorings, and CTD stations. A characteristic asymmetric "twin peak" signal is present during both time periods, implying the presence of both resuspension and advection. This is confirmed through the use of harmonic analysis. A seasonal variation in the relative importance of the resuspension and advection components is seen between the two observation periods, with the small (122µm) particles displaying different behaviours and providing a strong indication of the presence of flocculation. Approximate point flux calculations showed a reduction in the horizontal gradient of concentration, and subsequently the flood dominance of sediment transport, between May-June and February-March. This has been attributed to changes in biological activity and atmospheric forcing between the two observational periods. Ebb-dominant concentrations brought about by the horizontal concentration gradient were opposed by a possible asymmetrical flocculation signal with asymmetrically larger particles occurring during low water than high water. This led to faster settling particles at low water and therefore, over time, a tidal pumping mechanism which transports material up the estuary.

  13. Estuary Turbulence and Air-Water Carbon Dioxide Exchange

    Science.gov (United States)

    Orton, Philip Mark

    The mixing of constituents between estuarine bottom and surface waters or between estuarine surface waters and the atmosphere are two topics of growing interest, in part due to the potentially important role of estuaries in global carbon budgets. These two types of mixing are typically driven by turbulence, and a research project was developed to improve the scientific understanding of atmospheric and tidal controls on estuary turbulence and airwater exchange processes. Highlights of method development and field research on the Hudson River estuary include several deployments of bottom mounted current profilers to quantify the turbulent kinetic energy (TKE) budget, and construction and deployment of an instrumented catamaran that makes autonomous measurements of air-water CO2 exchange (FCO2), water TKE dissipation at 50 cm depth (epsilon50), and other physical properties just above and below the air-water interface. On the Hudson, wind correlates strongly with epsilon50, but surface water speed and airwater heat flux also have moderate correlations with epsilon50. In partially mixed estuaries such as the Hudson, as well as salt wedge estuaries, baroclinic pressure forcing typically causes spring ebb tides to have much stronger upper water column shear than flood tides. The Hudson data are used to show that this shear leads to local shear instability and stronger near-surface turbulence on spring ebbs. Also, buoyancy budget terms are compared to demonstrate how water-to-air heat fluxes can influence stratification and indirectly influence epsilon50. Looking more closely at the role of wind forcing, it is demonstrated that inland propagation of the sea breeze on warm sunny days leads to arrival in phase with peak solar forcing at seaward stations, but several hours later at up-estuary stations. Passage of the sea breeze front raises the air-water CO2 flux by 1-2 orders of magnitude, and drives epsilon50 comparable to spring tide levels in the upper meter of the water column. Modeling and observational studies often use remotely-measured winds to compute airwater fluxes (e.g. momentum, CO2), and this is shown to cause large flux errors during these periods, in terms of magnitude and diurnal phase.

  14. Abundance and Size of Gulf Shrimp in Louisiana's Coastal Estuaries following the Deepwater Horizon Oil Spill

    OpenAIRE

    Ham, Joris L.; Mutsert, Kim

    2014-01-01

    The Deepwater Horizon oil spill impacted Louisiana's coastal estuaries physically, chemically, and biologically. To better understand the ecological consequences of this oil spill on Louisiana estuaries, we compared the abundance and size of two Gulf shrimp species (Farfantepeneus aztecus and Litopeneus setiferus) in heavily affected and relatively unaffected estuaries, before and after the oil spill. Two datasets were used to conduct this study: data on shrimp abundance and size before the s...

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

    OpenAIRE

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

    2013-01-01

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

  16. Open water processes of the San Francisco Estuary: From physical forcing to biological responses

    OpenAIRE

    Wim Kimmerer

    2004-01-01

    This paper reviews the current state of knowledge of the open waters of the San Francisco Estuary. This estuary is well known for the extent to which it has been altered through loss of wetlands, changes in hydrography, and the introduction of chemical and biological contaminants. It is also one of the most studied estuaries in the world, with much of the recent research effort aimed at supporting restoration efforts. In this review I emphasize the conceptual foundations for our current under...

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

    OpenAIRE

    Drago Maguš

    2009-01-01

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

  18. Contemporary distribution of macrozoobenthic communities of the Yeisk estuary (Taganrog Bay of the Sea of Azov)

    Science.gov (United States)

    Nabozhenko, M. V.; Kovalenko, E. P.

    2011-08-01

    The contemporary distribution of macrozoobenthic communities of the Yeisk estuary is considered. Four basic types of communities are classified. Communities with domination of Tubificidae (Oligochaeta) occupy the greatest part of the estuary. Communities with domination of Amphipoda (Corophiidae) remained only in the northeast part of the reservoir. The unstable hydrological conditions and the absence of clearly expressed horohalinicum lead to mixing of Ponto-Caspian and Azov-Black Sea faunas in the Yeisk estuary.

  19. Distribution and sources of particulate organic matter in the Indian monsoonal estuaries during monsoon

    Science.gov (United States)

    Sarma, V. V. S. S.; Krishna, M. S.; Prasad, V. R.; Kumar, B. S. K.; Naidu, S. A.; Rao, G. D.; Viswanadham, R.; Sridevi, T.; Kumar, P. P.; Reddy, N. P. C.

    2014-11-01

    The distribution and sources of particulate organic carbon (POC) and nitrogen (PN) in 27 Indian estuaries were examined during the monsoon using the content and isotopic composition of carbon and nitrogen. Higher phytoplankton biomass was noticed in estuaries with deeper photic zone than other estuaries receiving higher suspended matter. The ?13CPOC and ?15NPN data suggest that relatively higher ?13CPOC (-27.9 to -22.6‰) and lower ?15NPN (0.7 to 5.8‰) were noticed in the estuaries located in the northern India, north of 16°N, and lower ?13CPOC (-31.4 to -28.2‰) and higher ?15NPN (5 to 10.3‰) in the estuaries located in the southern India. This is associated with higher Chl a in the northern than southern estuaries suggesting that in situ production contributed significantly to the POC pool in the former, whereas terrestrial sources are important in the latter estuaries. The spatial distribution pattern of ?15NPN is consistent with fertilizer consumption in the Indian subcontinent, which is twice as much in the northern India as in the south whereas ?13CPOC suggests that in situ production is a dominant source in the southern and terrestrial sources are important in the northern estuaries. Based on the Stable Isotope Analysis in R model, 40-90% (70-90%) of organic matter is contributed by C3 plants (freshwater algae) in the estuaries located in the northern (southern) India.

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

    International Nuclear Information System (INIS)

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

  1. Nontuberculous mycobacteria: incidence in Southwest Ireland from 1987 to 2000.

    LENUS (Irish Health Repository)

    Kennedy, M P

    2012-02-03

    SETTING: The Southwest of Ireland (Counties Cork and Kerry) 1987-2000, average population 549,500. OBJECTIVE: Nontuberculous mycobacteria (NTM) cause significant morbidity worldwide and the study of epidemiology and characteristics helps in their prevention and treatment. This study was performed to determine the incidence of NTM disease in comparison to Mycobacterium tuberculosis (M. tuberculosis) and Mycobacterium bovis (M. bovis) in Southwest Ireland, over the above time period. DESIGN: A retrospective study was carried out in all human isolates of NTM, M. tuberculosis and M. bovis between 1987 and 2000, in the Southwest Region of Ireland. RESULTS: The mean incidence of NTM (0.4\\/100,000 population) has risen since 1995, principally of pulmonary Mycobacterium avium intracellulare complex (MAC). The annual incidence of M. tuberculosis in humans over 14 years in the same region was 971\\/100,000 population with a significant reduction since 1994 and M. bovis remained constant at 0.5\\/100,000 population. CONCLUSION: The increasing incidence of disease causing NTM noted in Southwest Ireland reflects global data and is surmised to be due to an ageing population, increased incidence related to chronic fibrotic lung disease, and environmental mycobacterial factors.

  2. Bilingual Education in Southwest China: A Yingjiang Case

    Science.gov (United States)

    Wang, Ge

    2011-01-01

    Yingjiang is a frontier county in southwest Yunnan, China, with distinctive ethnic and cultural diversity. Bilingual education (BE) has been a prominent feature in Yingjiang since the 1950s due to supportive policies and measures at various levels. BE in Yingjiang developed so well in the 1980s that a bilingual school was awarded the title of…

  3. 78 FR 49253 - Pacific Southwest Recreation Resource Advisory Committee

    Science.gov (United States)

    2013-08-13

    ...Southwest Regional Office (Region 5), 1323 Club Drive, Vallejo, CA. Please call ahead to Frances Enkoji, at 707-562-8846...comments must be sent to Ramiro Villalvazo, 1323 Club Drive, Vallejo, CA 94592, or by email to rvillalvazo@fs.fed.us,...

  4. Borderlands of the Southwest: An Exercise in Geographical History

    Science.gov (United States)

    Thornton, Stephen J.

    2013-01-01

    In this article, the author argues that geography is more than a passive backdrop to time and events. Geographical perception is culturally mediated. He examines the case of the American Southwest and how its geography and historical heritage have been portrayed and how they might be otherwise if viewed through a different lens. (Contains 12…

  5. Marine conservation in a Southwest Portuguese natural park

    OpenAIRE

    Castro, J. J.; Cruz, T.

    2009-01-01

    Most of the SW Portuguese continental coast is protected by a natural park (Parque Natural do Sudoeste Alentejano e Costa Vicentina – PNSACV). A marine zone 2 km wide has been designated along the coast of this park (ca. 130 km) with oceanic sandy beaches, extensive rocky shores, and small estuaries and coastal lagoons. In this coast, intensive and traditional fisheries affect several target species for subsistence, commercial use or recreation. Most regulations are national and almost n...

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

    Science.gov (United States)

    Liu, Huan; Wu, Jia-xue

    2015-03-01

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

  7. Multibiomarker assessment of three Brazilian estuaries using oysters as bioindicators

    International Nuclear Information System (INIS)

    Oysters have been largely employed as bioindicators of environmental quality in biomonitoring studies. Crassostrea rhizophorae was selected to evaluate the health status of three estuarine areas impacted by anthropogenic activities along the Brazilian coast, in three estuarine complexes, ranging in latitude from 7 to 25 deg. S. In each estuary three sites were sampled in Winter and in Summer: a site considered as reference, and two sites next to contamination sources. Condition index was similar at all sites and estuaries, with the highest values found for Itamaraca oysters in Summer. Necrosis, hyperplasia, mucocyte hypertrophy and fusion of ordinary filaments were the main histopathological lesions observed. Muscle cholinesterase activity was overall similar, but with a strong seasonal effect. Inhibition or activation of branchial total ATPase and Na,K-ATPase activities at the contaminated sites was observed. The health status of these estuarine areas is quite similar, and the combined use of biomarkers is recommended

  8. Study of red tide prediction model for the Changjiang Estuary

    Science.gov (United States)

    Wang, Zheng-Fang; Lu, Hai-Yan; Zhang, Qing; Lu, Yong; Zeng, Jiang-Ning; Zhou, Qing-Song

    2000-12-01

    This paper based on field data (on red tide water quality monitoring at the Chaggjiang River mouth and Hutoudu mariculture area in Zhejiang Province from May to August in 1995, and May to September in 1996) presents an effective model for short term prediction of red tide in the Changjiang Estuary. The measured parameters include: depth, temperature, color diaphaneity, density, DO, COD and nutrients (PO4-P, NO2-N, NO3-N, NH4-N). The model was checked by field-test data, and compared with other related models. The model: Z=SAL-3.95 DO-2.974 PH-5.421 PO4-P is suitable for application to the Shengsi aquiculture area near the Changjiang Estuary.

  9. Effects of Prevailing Winds on Turbidity of a Shallow Estuary

    OpenAIRE

    Hyun Jung Cho

    2007-01-01

    Estuarine waters are generally more turbid than lakes or marine waters due to greater algal mass and continual re-suspension of sediments. The varying effects of diurnal and seasonal prevailing winds on the turbidity condition of a wind-dominated estuary were investigated by spatial and statistical analyses of wind direction, water level, turbidity, chlorophyll a, and PAR (Photosynthetically Active Radiation) collected in Lake Pontchartrain, Louisiana, USA. The prolonged prevailing winds were...

  10. The mineral resources of the English Channel and Thames Estuary

    OpenAIRE

    Bide, T.P.; Balson, P.S.; Mankelow, J M; Shaw, R A; Walters, A.S.; Campbell, E

    2013-01-01

    This report accompanies the Marine mineral resource map the marine sand and gravel resources of the English Channel and Thames Estuary (Bide et al, 2012). It has been published as part of the research project Mineral Resource Assessment of the UK Continental Shelf commissioned by The Crown Estate. The map is one of a series that covers the UK Continental Shelf (UKCS). Knowledge of mineral resources is essential for effective and sustainable planning decisions. The marine minera...

  11. Suspended matter and heavy metal content of the Elbe Estuary

    International Nuclear Information System (INIS)

    (1) In the River Elbe estuary there is a turbidity zone which is closely bound to the region of brackish waters. Its suspended matter content changes strongly with the tidal rhythm. Suspended matter and river bed sediments influence each other by exchanging their particles. Owing to that mechanism, the heavy metal ions bound or taken up by the suspended matter (sorption) enter the sediments. To obtain an estimation of the estuary's ability to cope with ( self purify ) a strong burden of industrial wastes, it is neccessary to take into consideration the absorbing capacity of both the mean suspension load and the sediments. (2) The concentration of nearly all heavy metal ions investigated in the suspension load decreases remarkably at the very beginning of the turbid zone already, in the Hamburg region. It indicates that the binding process are going on very rapidly and that the metal ion absorbing capacity of the Elbe estuary still requires only the first few miles of this self purification system. The results gained indicate that the suspended matter in Hamburg waters could bind or take up more heavy metal ions than are discharged into this area. (3) The concentration of most ions bound to the suspension material correlates very well with the grain size distribution of the (anorganic) particles. The concentration values decrease along the estuary and lead to a continuous transition to the values of the open sea. Cu, Ni and Cd appear to be captured preferably by organiappear to be captured preferably by organic suspended matter. This behaviour, however, is solely restricted to the turbid zone. In the open sea, after oxidation of the binding organic material, Cu and Ni correspond to the anorganic grain size distribution. (orig./HP)

  12. Sea fishes spawning pelagic eggs in the St Lucia estuary

    OpenAIRE

    A.D. Connell

    2011-01-01

    During September 1993, after the St Lucia estuary had beendosed to the sea for about nine months, two samples of liveplankton were collected at the mouth inside the closedestuary. Fish eggs from these samples were hatched andidentified by the characteristics of the eggs and early larvae.Pomadasys commersonnii and Crenidens crenidens werereared to confirm identification. Eggs of nine species werefound and all but one were identified to at least genus level.The unidentified egg was probably tha...

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  15. Use of Rare-Earth Elements as Tracers in Estuaries

    International Nuclear Information System (INIS)

    For large hydrology systems, such as estuaries, the method of stable-isotope tracing with post-sampling activation analysis shows much promise. The method retains the inherent sensitivity of radiation measurement without the concomitant chemical problems of dyes and radiation problems of radioisotope tracers. The rare-earth elements possess favourable nuclear, chemical, physical, and low natural abundance properties which make them suitable as a tracer for flow and dispersion studies in estuaries. Post-sample treatment of irradiation in a 10-kW nuclear reactor, radiochemical group separation, and gamma-ray spectroscopy yields detection limits of 1 ng for europium and 20 ng for lanthanum. Its use has been tested in the San Francisco Bay in which the background concentration of lanthanum is 180 ng/I and of europium 12 ng/l. The method can be used for tracing hydraulic flow or for persistence studies of suspended solids or settleable solid components in the estuary. The method competes favourably in cost, especially as the scale of the system increases. As many as six rare-earth elements can be measured simultaneously. They can be used in conjunction with radioactive rare-earth elements to extend tracing time or dilution range when the total amount of radiotracer is limited. (author)

  16. Predicting habitat associations of five intertidal crab species among estuaries

    Science.gov (United States)

    Vermeiren, Peter; Sheaves, Marcus

    2014-08-01

    Intertidal crab assemblages that are active on the sediment surface of tropical estuaries during tidal exposure play an important role in many fundamental ecosystem processes. Consequently, they are critical contributors to a wide range of estuarine goods and services. However, a lack of understanding of their spatial organization within a large landscape context prevents the inclusion of intertidal crabs into generally applicable ecological models and management applications. We investigated spatial distribution patterns of intertidal crabs within and among eight dry tropical estuaries spread across a 160 km stretch of coast in North East Queensland, Australia. Habitat associations were modelled for five species based on photographic sampling in 40-80 sites per estuarine up- and downstream component: Uca seismella occurred in sites with little structure, bordered by low intertidal vegetation; Macrophthalmus japonicus occupied flat muddy sites with no structure or vegetation; Metopograpsus frontalis and Metopograpsus latifrons occupied sites covered with structure in more than 10% and 25% respectively. Finally, both Metopograpsus spp. and Metopograpsus thukuhar occupied rock walls. Habitat associations were predictable among estuaries with moderate to high sensitivity and low percentages of false positives indicating that simple, physical factors were adequate to explain the spatial distribution pattern of intertidal crabs. Results provide a necessary first step in developing generally applicable understanding of the fundamental mechanisms driving spatial niche organization of intertidal crabs within a landscape context.

  17. Counting on ?-diversity to safeguard the resilience of estuaries.

    Science.gov (United States)

    de Juan, Silvia; Thrush, Simon F; Hewitt, Judi E

    2013-01-01

    Coastal ecosystems are often stressed by non-point source and cumulative effects that can lead to local-scale community homogenisation and a concomitant loss of large-scale ecological connectivity. Here we investigate the use of ?-diversity as a measure of both community heterogeneity and ecological connectivity. To understand the consequences of different environmental scenarios on heterogeneity and connectivity, it is necessary to understand the scale at which different environmental factors affect ?-diversity. We sampled macrofauna from intertidal sites in nine estuaries from New Zealand's North Island that represented different degrees of stress derived from land-use. We used multiple regression models to identify relationships between ?-diversity and local sediment variables, factors related to the estuarine and catchment hydrodynamics and morphology and land-based stressors. At local scales, we found higher ?-diversity at sites with a relatively high total richness. At larger scales, ?-diversity was positively related to ?-diversity, suggesting that a large regional species pool was linked with large-scale heterogeneity in these systems. Local environmental heterogeneity influenced ?-diversity at both local and regional scales, although variables at the estuarine and catchment scales were both needed to explain large scale connectivity. The estuaries expected a priori to be the most stressed exhibited higher variance in community dissimilarity between sites and connectivity to the estuary species pool. This suggests that connectivity and heterogeneity metrics could be used to generate early warning signals of cumulative stress. PMID:23755252

  18. The main phosphorous sources in the Changjiang estuary

    Science.gov (United States)

    Yang, Dongfang; Wang, Fan; Miao, Zhenqing; Chen, Yongli; Tong, Yuanzheng

    2008-11-01

    Analysis using historical data on the phosphate sources in Changjiang (Yangtze River) estuary show that phosphate was supplied equally from the east, south, west and north of the estuary. These sources include the Changjiang River, the Taiwan Warm Current (TWC), a cyclone-type eddy, and the 32°N Upwelling, supplying different phosphates in different times, ways and intensities. The magnitude of their supplying phosphate concentration was related with the size in the order of the Changjiang River the TWC > the cyclone-type eddy > the 32°N Upwelling. The four sources supplied a great deal of phosphate so that the phosphate concentration in the estuary was kept above 0.2 ?mol/L in previous years, satisfying the phytoplankton growth. The horizontal and vertical distribution of the phosphate concentration showed that near shallow marine areas at 122°E/31°N, the TWC in low nutrient concentration became an upwelling through sea bottom and brought up nutrients from sea bottom to marine surface. In addition, horizontal distribution of phosphate concentration was consistent with that of algae: Rhizosolenia robusta, Rhizosolenia calcaravis and Skeletonema, which showed that no matter during high water or low water of Changjiang River, these species brought by the TWC became predominant species. Therefore, the authors believe that the TWC flowed from south to north along the coast and played a role in deflecting the Changjiang River flow from the southern side.

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

    International Nuclear Information System (INIS)

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

  20. North Inlet ? Winyah Bay (NIW) National Estuarine Research Reserve Meteorological Data, North Inlet Estuary, Georgetown, South Carolina: 1997 ? 1999.

    Baruch Institute for Marine and Coastal Sciences, Univ of South Carolina — The North Inlet Estuary and the adjacent lower northeastern section of Winyah Bay Estuary were designated as part of the National Estuarine Research Reserve System...

  1. Seasonal variations of nitrate reducing and denitrifying bacteria utilizing hexadecane in Mandovi estuary, Goa, West Coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Sousa, T.D.; Ingole, B.; Sousa, S.D.; Bhosle, S.

    2013-01-01

    Mandovi estuary has a prolific population of heterotrophic bacteria due to the influx of nutrients including nitrate and organic hydrocarbons. Seasonal sampling at various locations along the estuary was carried out to isolate nitrate reducing...

  2. Influence of allochthonous input on autotrophiceheterotrophic switch-over in shallow waters of a tropical estuary (Cochin Estuary), India

    Digital Repository Service at National Institute of Oceanography (India)

    Thottathil, S.D.; Balachandran, K.K.; Gupta, G.V.M.; Madhu, N.V.; Nair, S.

    2008-01-01

    sediments along the central southwest coast of India. Journal of Coastal Research 19, 664e683. Biddanda, B.A., Cotner, J.B., 2002. Love handles in aquatic ecosystems: Role of dissolved organic drawdown, resuspended sediments and terrigenous inputs in carbon...

  3. ???–??????????????????? Intertidal Heavy Metal Distribution Characteristics and Environmental Effects from the Luanhe Estuary to Douhe Estuary

    Directory of Open Access Journals (Sweden)

    ???

    2012-09-01

    Full Text Available ???????????????????????????????????????????????????????????????????????????????????????????????????????????????????????13???????????????31????X??????(XRF??????(AAS???????????(ICP-MS?????????????????????????????????????Pb?????????????Zn????????Ni??????????As?????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????Accompanied by urbanization and industrialization process in Tangshancoastal zone, the heavy metal pollution increased. The representative parts, such as Jianhe Estuary, the Luannan Zuidong Industrial Zone, Caofeidian Industrial Zone, the Qinglonghe Estuary, Caofeidian Wetlands, the Laoting Qianshui Bay, and Jingtang Port in Bohai West Bank, were chosen, selecting the 13 sampling sites, 31 surface sediment samples.Dissolved inorganic nutrients and chlorophyll A in an estuary receiving sewage treatment plant effluents: Cachoeira River estuary (NE Brazil).

    Science.gov (United States)

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

    2013-07-01

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

  4. E-Estuary: Developing a Decision Support System for Coastal Management in the Conterminous United States (IAHR)

    Science.gov (United States)

    Ready access to geographic information is needed to support management decisions for estuaries at local, state, regional, and national scales. The U.S. Environmental Protection Agency (US EPA) is developing e-Estuary, a decision-support system for coastal management. E-Estuary ...

  5. E-estuary: A Decision Support System for Coastal Water and Ecosystem Management in the US (CZ09)

    Science.gov (United States)

    Ready access to geographic information is needed to support management decisions for estuaries at local, state, regional, and national scales. The U.S. Environmental Protection Agency (US EPA) is developing e-Estuary, a decision-support system for coastal management. E-Estuary ...

  6. E-Estuary: Developing a Decision-support System for Coastal Management in the Counterminous Untied States (Coastal Geotools 09)

    Science.gov (United States)

    Ready access to geographic information is needed to support management decisions for estuaries at local, state, regional, and national scales. The U.S. Environmental Protection Agency (US EPA) is developing e-Estuary, a decision-support system for coastal management. E-Estuary ...

  7. Terrigenous Sedimentation Patterns at Reefs Adjacent to the Guanica Bay Watershed, Southwest Puerto Rico

    Science.gov (United States)

    Sherman, C.; Whitall, D.

    2014-12-01

    Guanica Bay is an estuary on the southwest coast of Puerto Rico with numerous nearshore reefs located in adjacent coastal waters. As part of the multi-agency Guanica Bay Watershed Project, a study was undertaken to establish baseline levels of terrigenous sedimentation reaching reefs adjacent to the Guanica Bay watershed as well as establish spatial and temporal patterns in its delivery. To characterize and quantify sedimentation patterns, sediment traps were established at nine reef sites occurring along an ~ 14 km stretch of coastline centered on the outlet of the bay. Sites were located at shallow reefs within 2 km of the shore at depths of ~ 10 m. Two additional sites were located at the mouth of the Rio Loco where it empties into Guanica Bay and at the mouth of the bay where it opens into adjacent coastal waters. Traps were collected monthly from August 2009 through July 2012 to determine both the amount of sediment accumulation (mg cm-2 day-1) and its composition. Composition is expressed in terms of relative amounts of calcium carbonate (in situ production), organic material and terrigenous material. Average trap accumulation rates among the reef sites ranged from ~ 3 to 28 mg cm-2 day-1. Average percent terrigenous material within reef accumulation ranged from ~ 20% to 30%. While trap accumulation rates are highly variable on both spatial and temporal scales, the composition of sediments and relative amount of terrigenous material is fairly uniform. Similar temporal patterns in accumulation rates among the sites without corresponding changes in composition of sediments point to resuspension of bottom sediments by wave action as a primary driver of sedimentary dynamics at these reefs. Sites closest to Guanica Bay display the highest degree of terrigenous influence in terms of trap accumulation rates and percent terrigenous material, which is consistent with Guanica Bay serving as a local source of terrigenous material to coastal waters. However, the lack of east-west trends relative to the bay mouth in either trap accumulation rates or percent terrigenous material indicates that Guanica Bay is not the sole or necessarily primary source of terrigenous materials reaching nearshore reefs.

  8. Second international symposium on the biogeochemistry of model estuaries: Estuarine processes in global change

    Energy Technology Data Exchange (ETDEWEB)

    1991-12-31

    This report consists of abstracts of papers presented at the symposium of Biogeochemistry. The main topics discussed at the meeting are; nutrient and mineral cycling, trace element distribution, sources and sinks of estuaries, sedimentation, importance of organic matter, and other biogeochemical processes of estuaries.

  9. Salt intrusion in multi-channel estuaries: a case study in the Mekong Delta, Vietnam

    Directory of Open Access Journals (Sweden)

    A. D. Nguyen

    2006-01-01

    Full Text Available There is a well-tested theory for the computation of salt intrusion in alluvial estuaries that is fully analytical and predictive. The theory uses analytical equations to predict the mixing behaviour of the estuary based on measurable quantities, such as channel topography, river discharge and tidal characteristics. It applies to single-channel topographies and estuaries that demonstrate moderate tidal damping. The Mekong delta is a multi-channel estuary where the tide is damped due to a relatively strong river discharge (in the order of 2000 m3/s, even during the dry season. As a result the Mekong is a strongly riverine estuary. This paper aims to test if the theory can be applied to such a riverine multi-channel estuary, and to see if possible adjustments or generalisations need to be made. The paper presents salt intrusion measurements that were done by moving boat in 2005, to which the salt intrusion model was calibrated. The theory has been expanded to cater for tidal damping. Subsequently the model has been validated with observations made at fixed locations over the years 1998 and 1999. Finally it has been tested whether the Mekong calibration fits the overall predictive equations derived in other estuaries. The test has been successful and led to a slight adjustment of the predictive equation to cater for estuaries that experience a sloping bottom.

  10. An approach to developing nutrient criteria for Pacific Northwest Estuaries: A case study

    Science.gov (United States)

    This presentation provides an overview of an approach to developing nutrient criteria for Pacific Northwest (PNW) estuaries, based on a case study of Yaquina Estuary, Oregon. The approach is based on a synthesis of research from field studies, analyses of historical trends in wat...

  11. The relationship between dissolved humic acids and soluble iron in estuaries

    Science.gov (United States)

    Fox, L. E.

    1984-01-01

    Dissolved humic acid and soluble iron appear to be chemically unassociated in estuaries despite their coincident removal. This conclusion is supported by differences in the aggregation kinetics of soluble iron and dissolved humic acid, the inability of extracted humic acid to stabilize laboratory preparations of ferric hydroxide, and decreasing ratios of humic acid carbon to soluble iron along the axes of some estuaries.

  12. Liver oxidative stress of the grey mullet Mugil cephalus presents seasonal variations in Ennore estuary

    Directory of Open Access Journals (Sweden)

    E. Padmini

    2008-11-01

    Full Text Available The objective of this study was to determine the liver oxidative stress status of grey mullets living in heavy-metal-rich polluted Ennore estuary compared with unpolluted Kovalam estuary. Fish were collected from both estuaries during the monsoon and summer seasons from October 2004 to September 2006. Fish liver homogenate (N = 20 per group was prepared for evaluating oxidative stress parameters. Fish living in the polluted estuary had significantly higher lipid oxidation products, conjugated dienes (0.346 ± 0.017 vs 0.141 ± 0.012 DA233/mg protein, lipid hydroperoxides (0.752 ± 0.032 vs 0.443 ± 0.03 nmol/mg protein, and lipid peroxides (3.447 ± 0.14vs 1.456 ± 0.096 nmol MDA/mg protein than those of the unpolluted estuary during the summer. In contrast, significantly lower levels of superoxide dismutase (20.39 ± 1.14 vs 53.63 ± 1.48 units/mg protein and catalase (116 ± 6.87vs 153 ± 8.92 units/mg protein were detected in the liver of fish from the polluted estuary (Ennore compared to fish from the unpolluted estuary (Kovalam during the summer. Variations in most of the oxidative stress parameters were observed between the summer and monsoon seasons, indicating the importance of seasonal variation for estuaries and their inhabitants.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1982-01-01

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

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

    International Nuclear Information System (INIS)

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

  15. Liver oxidative stress of the grey mullet Mugil cephalus presents seasonal variations in Ennore estuary

    Scientific Electronic Library Online (English)

    E., Padmini; B., Vijaya Geetha; M., Usha Rani.

    2008-11-01

    Full Text Available The objective of this study was to determine the liver oxidative stress status of grey mullets living in heavy-metal-rich polluted Ennore estuary compared with unpolluted Kovalam estuary. Fish were collected from both estuaries during the monsoon and summer seasons from October 2004 to September 200 [...] 6. Fish liver homogenate (N = 20 per group) was prepared for evaluating oxidative stress parameters. Fish living in the polluted estuary had significantly higher lipid oxidation products, conjugated dienes (0.346 ± 0.017 vs 0.141 ± 0.012 DA233/mg protein), lipid hydroperoxides (0.752 ± 0.032 vs 0.443 ± 0.03 nmol/mg protein), and lipid peroxides (3.447 ± 0.14vs 1.456 ± 0.096 nmol MDA/mg protein) than those of the unpolluted estuary during the summer. In contrast, significantly lower levels of superoxide dismutase (20.39 ± 1.14 vs 53.63 ± 1.48 units/mg protein) and catalase (116 ± 6.87vs 153 ± 8.92 units/mg protein) were detected in the liver of fish from the polluted estuary (Ennore) compared to fish from the unpolluted estuary (Kovalam) during the summer. Variations in most of the oxidative stress parameters were observed between the summer and monsoon seasons, indicating the importance of seasonal variation for estuaries and their inhabitants.

  16. Distribution and sources of particulate organic matter in the Indian monsoonal estuaries during monsoon

    Digital Repository Service at National Institute of Oceanography (India)

    Sarma, V.V; Krishna, M.S.; Prasad, V; Kumar, B.S.K.; Naidu, S.A; Rao, G.D.; Viswanadham, R.; Sridevi, T.; Kumar, P.P.; Reddy, N

    2014-01-01

    located in the northern India, north of 16°N, and lower delta13CPOC (-31.4 to -28.2‰) and higher delta15CPN (5 to 10.3‰) in the estuaries located in the southern India. This is associated with higher Chl a in the northern than southern estuaries suggesting...

  17. Levels of C{sub 10}-C{sub 13} polychloro-n-alkanes in marine mammals from the Arctic and the St. Lawrence River estuary

    Energy Technology Data Exchange (ETDEWEB)

    Tomy, G.T.; Muir, D.C.G.; Stern, G.A.; Westmore, J.B.

    2000-05-01

    Marine mammals from various regions of the Arctic and the St. Lawrence River estuary were examined for the first time for levels of C{sub 10}--C{sub 13} polychloro-n-alkanes (sPCAs). Respective mean total sPCA concentrations in the blubber of beluga whales (Delphinapterus leucas) from Saqqaq and Nuussuaq, western Greenland, were 0.23 {+-} 0.02 (n = 2) and 0.164 {+-} 0.06 {micro}g/g (n = 2), similar to that in beluga from the Mackenzie Delta in the western Canadian Arctic 0.21 {+-} 0.08 {micro}g/g (m = 3). sPCAs levels were higher in beluga blubber from the St. Lawrence River (0.37 to 1.4 {micro}g/g). Mean sPCA concentrations in the blubber samples from walruses (Odobenus rosmarus) (Thule, northwest Greenland) and ringed seal (Phoca hispida) (Eureka, southwest Ellesmere Island) were 0.43 {+-} 0.06 (n = 2) and 0.53 {+-} 0.2 {micro}g/g (n = 6), respectively. Relative to commercial sPCA formulations, samples from the Arctic marine mammals showed a predominance of the shorter chain length lower percent chlorinated PCA congeners, the more volatile components of industrial formulations. This observation is consistent with long-range atmospheric transport of sPCAs to this region. The profiles of the belugas from the St. Lawrence River estuary, however, had higher proportions of the less volatile sPCA congeners, implying that contamination to this region is probably from local sources.

  18. Implications of the divergent use of a suite of estuaries by two exploited marine fish species.

    Science.gov (United States)

    Potter, I C; Chuwen, B M; Hesp, S A; Hall, N G; Hoeksema, S D; Fairclough, D V; Rodwell, T M

    2011-09-01

    Biological characteristics of the marine species King George whiting Sillaginodes punctatus and Australian herring Arripis georgianus in three seasonally open estuaries (Broke, Irwin and Wilson Inlets), one permanently open estuary (Oyster Harbour) and one normally closed estuary (Wellstead Estuary) on the south coast of Western Australia have been determined and compared. Sillaginodes punctatus enters the seasonally and permanently open estuaries early in life and reaches total lengths (L(T)) >280 mm at which it can be legally retained and thus contributes to commercial and recreational fisheries in these systems. This sillaginid almost invariably emigrates from these estuaries before reaching its typical size at maturity (L(T50)) and does not return after spawning in marine waters. In contrast, virtually all female A. georgianus (? 98%) in the three seasonally open estuaries and the majority in the normally closed (89·5%) and permanently open estuaries (83%) exceeded the L(T50) of this species at maturity, reflecting the fact that the nursery areas of this species are predominantly located much further to the east. Although adult females of A. georgianus in seasonally open and normally closed estuaries had developed mature ovaries by autumn, at which time they were prevented from migrating to the sea by closure of the estuary mouths, this species did not spawn in those estuaries. The oocytes in their ovaries were undergoing extensive atresia, a process that had been incipient prior to oocyte maturation. As the adult females of A. georgianus in the permanently open Oyster Harbour at this time all possessed resting gonads, i.e. their oocytes were all previtellogenic, the adults that were present in that estuary earlier and were destined to spawn in autumn must have emigrated from that permanently open estuary to their marine spawning areas prior to the onset of gonadal recrudescence. The body masses at length of A. georgianus, which were almost invariably higher in summer and autumn than in winter and spring, were greater in the very productive environments of the seasonally open and normally closed estuaries than in the less productive and essentially marine environment of Oyster Harbour and coastal marine waters. In general, the same pattern of differences between water bodies was exhibited by the growth of A. georgianus and by the more restricted data for body mass at L(T) and growth of S. punctatus. Despite an increase in anthropogenic activities in Wilson Inlet over the last two decades, the growth of both species was very similar to that recorded 20 years earlier. The fisheries implications of the results for the two species are discussed. PMID:21884106

  19. Heavy Metals (Cd, Cu, Cr, Pb and Zn) in Meretrix meretrix Roding, Water and Sediments from Estuaries in Sabah, North Borneo

    Science.gov (United States)

    Abdullah, Mohd. Harun; Sidi, Jovita; Aris, Ahmad Zaharin

    2007-01-01

    Concentrations of heavy metals (Cd, Cu, Cr, Pb and Zn) in tissues of Meretrix meretrix Roding (M. meretrix R.), water and sediments from two estuaries were determined. One estuary is located in an urban area of Kota Kinabalu (Likas estuary) and the other in a rural district of Kota Belud (Kota Belud estuary), where both are in Sabah, North of…

  1. Ambiguities in the classification of Cochin Estuary, West Coast of India

    Directory of Open Access Journals (Sweden)

    A. Shivaprasad

    2013-03-01

    Full Text Available Cochin Estuary is a unique complex system along Indian coastline with a widespread area at the upstream. The fluctuations in salinity are of extreme kind ranging from entirely riverine to entirely saline. The high runoff months are characterized by monsoonal spells causing intense flushing. During the peak dry period, the runoff is less but steady providing a stable environment. River runoff is controlled by short term variations rather than long term variations. Using large comprehensive data sets, an attempt is made to evaluate several classification schemes for the estuary. The existing methods proved to be insufficient to represent the real salient features of this typical estuary. Arguments are also presented to illustrate the confusion in the names by which the estuary is commonly known. Therefore, a new nomenclature is proposed as "Cochin Monsoonal Estuarine Bay" embodying the physiographic, hydrographic and biological features of the estuary.

  2. What does impacted look like? High diversity and abundance of epibiota in modified estuaries.

    Science.gov (United States)

    Clark, Graeme F; Kelaher, Brendan P; Dafforn, Katherine A; Coleman, Melinda A; Knott, Nathan A; Marzinelli, Ezequiel M; Johnston, Emma L

    2015-01-01

    Ecosystems modified by human activities are generally predicted to be biologically impoverished. However, much pollution impact theory stems from laboratory or small-scale field studies, and few studies replicate at the level of estuary. Furthermore, assessments are often based on sediment contamination and infauna, and impacts to epibiota (sessile invertebrates and algae) are seldom considered. We surveyed epibiota in six estuaries in south-east Australia. Half the estuaries were relatively pristine, and half were subject to internationally high levels of contamination, urbanisation, and industrialisation. Contrary to predictions, epibiota in modified estuaries had greater coverage and were similarly diverse as those in unmodified estuaries. Change in epibiota community structure was linearly correlated with sediment-bound copper, and the tubeworm Hydroides elegans showed a strong positive correlation with sediment metals. Stressors such as metal contamination can reduce biodiversity and productivity, but others such as nutrient enrichment and resource provision may obscure signals of impact. PMID:25282127

  3. Light-induced bird strikes on vessels in Southwest Greenland

    DEFF Research Database (Denmark)

    Merkel, Flemming Ravn; Johansen, Kasper Lambert

    2011-01-01

    Light-induced bird strikes are known to occur when vessels navigate during darkness in icy waters using powerful searchlight. In Southwest Greenland, which is important internationally for wintering seabirds, we collected reports of incidents of bird strikes over 2–3 winters (2006–2009) from navy vessels, cargo vessels and trawlers (total n = 19). Forty-one incidents were reported: mainly close to land (<4 km, 78%), but one as far offshore as 205 km. Up to 88 birds were reported killed in a single incident. All occurred between 5 p.m. and 6 a.m. and significantly more birds were involved when visibility was poor (snow) rather than moderate or good. Among five seabird species reported, the common eider (Somateria mollissima) accounted for 95% of the bird casualties. Based on spatial analyses of data on vessel traffic intensity and common eider density we are able to predict areas with high risk of bird strikes in Southwest Greenland.

  4. Optical properties of a tropical estuary during wet and dry conditions in the Nha Phu estuary, Khanh Hoa Province, south-east Vietnam

    DEFF Research Database (Denmark)

    Lund-Hansen, Lars Chresten; Hai, Doan Nhu

    2010-01-01

    There has been a strong research focus on optical properties in temperate estuaries but very much less in tropical estuaries. These properties comprise light and beam attenuation dominated by suspended particulate matter, Chl a, and CDOM. Spatially and temporally distributed data on optical properties in a tropical wet and dry estuary are compared and discussed in relation to those of temperate estuaries. Sampling in the Nha Phu estuary, Vietnam, consisted of five stations on a transect from head to mouth that was sampled four times during dry conditions and three times during wet conditions between May 2006 and April 2008. Methods comprised CTD, optical measurements, and water sampling for suspended matter, Chl a, and CDOM. Results showed high light attenuation—K d(PAR)—in wet conditions and low in dry. K d(PAR) was highest at the estuary head and lower in the outer part. Spatial and temporal variations in K d(PAR) were in general dominated by variations in suspended particulate matter concentrations in both wet and dry conditions. Chl a concentrations were low and showed no strong variations between wet and dry conditions. CDOM absorption coefficients were higher in wet conditions with high values at the head and lower in the central part of the estuary. The depth of the photic zone was reduced by up to 50% during wet conditions. A residence time in the estuary of 5–6 days was derived from the rate of change of K d(PAR) after a period of heavy rain and discharge of freshwater into the estuary. This complied with a residence time of four and a half days derived from a basic physical relation. Optical properties were in general comparable to temperate estuaries in dry conditions although Chl a concentrations were lower in Nha Phu. A second distinctive point, as compared to temperate estuaries, was the episodic character with days of strong rainfall followed by longer periods of dry weather. All sampling, both wet and dry, was carried out in the dry season which implies a less definitive perception of wet and dry seasons.

  5. Geothermal development in southwest Idaho: the socioeconomic data base

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, S.G.; Russell, B.F.

    1979-09-01

    This report inventories, analyzes, and appraises the exiting socioeconomic data base for the ten counties in southwest Idaho that would be impacted by any significant geothermal development. The inventory describes key sociological demographic, and economic characteristics, and presents spatial boundaries, housing data, and projections of population and economic activity for the counties. The inventory identifies the significant gaps in the existing data base and makes recommendations for future research.

  6. Geothermal development in southwest Idaho: the socioeconomic data base

    Energy Technology Data Exchange (ETDEWEB)

    Spencer,S.G.; Russell, B.F. (eds.)

    1979-09-01

    This report inventories, analyzes, and appraises the existing socioeconomic data base for the ten counties in southwest Idaho that would be impacted by any significant geothermal development. The inventory describes key sociological demographic, and economic characteristics, and presents spatial boundaries, housing data, and projections of population and economic activity for the counties. The inventory identifies the significant gaps in the existing data base and makes recommendations for future research.

  7. Migmatitic rocks southwest of the Barberton greenstone belt

    International Nuclear Information System (INIS)

    A geologic survey was done on the migmatitic rocks southwest of the Barberton greenstone belt. A table is given on the chemical analyses of components from migmatic outcrops in this area, as well as on the chemical analyses of some selected rock types found in greenstone xenoliths, together with leuco-biotite tomalite/tronomjemite gneisses in the area surrounding the Boesmanskop syenite pluton. Isotope dating was also used in the survey

  8. Millipedes (Diplopoda of twelve caves in Western Mecsek, Southwest Hungary

    Directory of Open Access Journals (Sweden)

    Angyal, D.

    2013-11-01

    Full Text Available Twelve caves of Western Mecsek, Southwest Hungary were examined between September 2010 and April 2013from the millipede (Diplopoda faunistical point of view. Ten species were found in eight caves, which consistedeutroglophile and troglobiont elements as well. The cave with the most diverse fauna was the Törökpince Sinkhole, while thetwo previously also investigated caves, the Abaligeti Cave and the Mánfai-k?lyuk Cave provided less species, which couldbe related to their advanced touristic and industrial utilization.

  9. Iron-deficiency anemia among children in southwest Iran

    OpenAIRE

    Tabibi, Ramin

    2007-01-01

    Background. Iron deficiency is a major health problem worldwide and especially in developing countries. Irondeficiency anemia has adverse effects on the development of children. Objective. The purpose of this study was to determine the prevalence of iron-deficiency anemia in children under 5 years of age in southwest Iran. The study also sought to investigate the association between socioeconomic,demographic, cultural, and nutritional factors and iron-deficiency anemia in the selected area...

  10. The chimpanzees of Oluwa Forest Reserve, southwest Nigeria

    OpenAIRE

    Ogunjemite, B. G.; Olaniyi, O. E.

    2012-01-01

    The lack of accurate information on the population of chimpanzees (Pan troglodytes) is a cause for concern on their conservation and management in Southwest Nigeria. We conducted surveys on the chimpanzees of Oluwa Forest Reserve, Ondo State between the month of September 2011 and February 2012. We used the combination of recce survey and GIS mapping to determine Chimpanzees’ locations in the reserve. Chimpanzee distribution was confined to the central portion of the OA2 axis of the res...

  11. Characteristics of moisture flux convergence in Central Southwest Asia

    Science.gov (United States)

    Malik, Khalid M.; Taylor, Peter A.; Szeto, Kit

    2015-05-01

    The National Centers for Environmental Prediction-National Center for Atmospheric Research (NCEP-NCAR) reanalysis data have been used to compute the moisture flux convergence (MFC) over Central Southwest Asia (CSWA) between 45°-75° E and 25°-40° N. The present study focuses on the 1969-2007 period, and both horizontal distributions and vertical profiles of MFC have been calculated and compared. Moisture is transported into the region from the west throughout the year. In this region, winter is the wettest season with the most precipitation. Areas of high moisture convergence are observed in the east and southwest. Moisture convergence in the east and southwest are associated with topographic effects. Our study also examined composites of moisture flux convergence that characterized the wettest and the driest years in this area. The magnitude of the monthly MFC differs considerably between these two extremes. The spatial distribution of moisture flux convergence during the recent drought period (1999-2001) was also examined in order to understand how moisture transport affects drought. Deficiency of precipitation during drought periods appears to be due to deviation of moisture transport away from the region.

  12. The Southwest Pacific Ocean circulation and climate experiment (SPICE)

    Science.gov (United States)

    Ganachaud, A.; Cravatte, S.; Melet, A.; Schiller, A.; Holbrook, N. J.; Sloyan, B. M.; Widlansky, M. J.; Bowen, M.; Verron, J.; Wiles, P.; Ridgway, K.; Sutton, P.; Sprintall, J.; Steinberg, C.; Brassington, G.; Cai, W.; Davis, R.; Gasparin, F.; Gourdeau, L.; Hasegawa, T.; Kessler, W.; Maes, C.; Takahashi, K.; Richards, K. J.; Send, U.

    2014-11-01

    The Southwest Pacific Ocean Circulation and Climate Experiment (SPICE) is an international research program under the auspices of CLIVAR. The key objectives are to understand the Southwest Pacific Ocean circulation and the South Pacific Convergence Zone (SPCZ) dynamics, as well as their influence on regional and basin-scale climate patterns. South Pacific thermocline waters are transported in the westward flowing South Equatorial Current (SEC) toward Australia and Papua-New Guinea. On its way, the SEC encounters the numerous islands and straits of the Southwest Pacific and forms boundary currents and jets that eventually redistribute water to the equator and high latitudes. The transit in the Coral, Solomon, and Tasman Seas is of great importance to the climate system because changes in either the temperature or the amount of water arriving at the equator have the capability to modulate the El Niño-Southern Oscillation, while the southward transports influence the climate and biodiversity in the Tasman Sea. After 7 years of substantial in situ oceanic observational and modeling efforts, our understanding of the region has much improved. We have a refined description of the SPCZ behavior, boundary currents, pathways, and water mass transformation, including the previously undocumented Solomon Sea. The transports are large and vary substantially in a counter-intuitive way, with asymmetries and gating effects that depend on time scales. This paper provides a review of recent advancements and discusses our current knowledge gaps and important emerging research directions.

  13. Lattice Boltzmann Hydrodynamic and Transport Modeling of Everglades Mangrove Estuaries

    Science.gov (United States)

    Sukop, M. C.; Engel, V.

    2010-12-01

    Lattice Boltzmann methods are being developed and applied to simulate groundwater and surface water flows, and heat, solute, and particle transport. Their ability to solve Navier-Stokes, St. Venant, or Darcy equations with closely coupled solute transport and density-dependent flow effects in geometrically complex domains is attractive for inverse modeling of tracer release data and forward modeling of carbon transport in mangrove estuaries under various future conditions. Key physical processes to be simulated include tidal cycles, storm surge, sea level change, variable upstream stage, subsurface groundwater inputs, and precipitation/recharge and their effects on estuary salinity and carbon transport in the estuaries and groundwater beneath the mangroves. Carbon sources and storage in the aquifer and exchanges at the mangrove-estuary interface and carbon transformations in the water column also need to be simulated. Everglades tidal mangrove estuaries are characterized by relatively high velocity (approaching 1 m s-1) tidal flows. The channels are generally less than 2 m in depth. Tidal fluctuations approach 2 m leading to significant areas of periodic inundation and emergence of oyster beds, shell beaches, mangrove root masses, and sandy beaches. Initial models are two-dimensional, although a three-dimensional model explicitly incorporating bathymetry, density-dependent flow, and wind-driven circulation could be developed. Preliminary work highlights some of the abilities of early models. A satellite image of a 64-km2 area surrounding a CO2 flux tower is used to provide the model geometry. Model resolution is 15 m per grid node. A sinusoidal tidal stage variation and constant, high salinity are applied to the Gulf side of the model while a constant stage (corresponding to mean tide), zero salinity boundary is applied on the inland side. The Navier-Stokes equations coupled with the advection-diffusion equation are solved in the open channels. The mangrove areas are simulated as a porous medium, where transport is controlled by the advection-dispersion equation. As expected, incoming tides carry salinity up the channels and outgoing tides tend to flush the salinity from the channels. Salinity also invades the groundwater beneath the mangroves, which then contributes salinity back to the channel during outgoing tides. Although some large-scale aspects of the tidal flows are captured in these preliminary simulations, the current simulations are at Reynolds numbers smaller than those that characterize the real flows. More realistic simulations would require much higher resolution and have to be implemented on large-scale parallel computing platforms possibly using sub-grid turbulence models. Tracer data from experimental releases of SF6 will be used to estimate the parameters controlling transport in the estuary via inverse modeling with the parameter estimation code PEST. SF6 undergoes volatilization from the water column and is therefore a reasonable surrogate for air-sea CO2 gas exchange in the modeling framework. The parameters estimated from the tracer test inversion will be used in predictive modeling of the effects of sea level variations on salinity and carbon transport.

  14. [Zooplankton in north branch waters of Changiiang Estuary].

    Science.gov (United States)

    Xu, Zhaoli

    2005-07-01

    Based on the investigation data during the high-water (July, 2003) and low-water (January, 2004) periods, a causal analysis was made on the variation of zooplankton distribution in the north branch waters of the Changjiang Estuary. The results showed that in high-water period, the average of zooplankton biomass was 234.38 mg x m(-3), being 141.35 mg x m(-3) in flood tide and 327.40 mg x m(-3) in ebb tide, while in low-water period, it was 188.81 mg x m(-3), being 184.69 mg x m(-3) in flood tide and 192.93 mg x m(-3) in ebb tide. The biomass increased from the east to the west in flood tide, but a contrary trend was observed in ebb tide. The species number did not change obviously both in flood tide and in ebb tide. The value of diversity index (H') was higher in flood tide than in ebb tide. In high-water period, the biomass near the north shore was higher than that near the south shore, but it was contrary in the ebb tide. The difference between the waters of two shores was not obvious in low-water period as in high-water period, though the trend of biomass variation was similar. The variation of zooplankton distribution in the north branch waters of the Changjiang Estuary had a close relation with the seasonal changes of zooplankton biomass outside the Changjiang Estuary and the tide, but not significantly related with the Changjiang runoff water. Coriolis force accounted for the difference of zooplankton biomass in the waters of two shores via tide movement. PMID:16252880

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

    International Nuclear Information System (INIS)

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

  16. Oil spill response planning on the Columbia river estuary

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2014-11-01

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

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

    Science.gov (United States)

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

    1982-06-25

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

  19. Nutrient budgets for large Chinese estuaries and embayment

    Science.gov (United States)

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

    2009-01-01

    Nutrient concentrations among the Chinese rivers and bays vary 10-75 fold depending on nutrient elements. The silicic acid levels in South China rivers are higher than those from North China rivers and the yields of dissolved silicate increased from the north to the south of China, indicating the effect of climate on weathering. The nutrient levels in Chinese rivers are higher than those from the large and less-disturbed world rivers such as Amazon and Zaire, but comparable to the values for European and North American polluted and eutrophic rivers like the Loire and Po. This may be ascribed to both of extensive leaching and influences from agricultural and domestic activities over the drainage basins of Chinese rivers. DIN:PO3-4 ratios in most of Chinese rivers and bays are higher (up to 2800) than the other rivers in the world. The atomic ratios of DIN to PO43- in the major Chinese rivers and embayment decrease in exponential trend with increase in the atomic ratios of PO43- to Si(OH)4, indicating that primary production in coastal environments changes with the nutrients transport when the urbanization develops to a certain extent, and the potential limited nutrient elements can be changed from phosphorus to nitrogen limitation, which can modify aquatic food webs and then the ocean ecosystem. A simple steady-state mass-balance box model was employed. The output shows that the estuaries and embayment behave as a sink or source of nutrients. For the major Chinese estuaries, both residual and mixing flow transport nutrients off the estuaries, and nutrient transport fluxes in summer is 3-4 fold that in winter except comparable for NH4+. These fluxes are 1.0-1.7 fold that estimated by timing riverine nutrient concentrations and freshwater discharge. For the major Chinese embayment, nutrient elements are transported to China Seas except PO43- and Si(OH)4 in Sanggou Bay and Jiaozhou Bay. Seasonally, nutrients transport fluxes off the bays in the summer are 2.2-7.0 fold that in the winter. In the embayment, the exchange flow dominated the water budgets, resulting in average system salinity approaching the China seas salinity where river discharge is limited. The major Chinese estuaries and embayment transport 1.0-3.1% of nitrogen, 0.2-0.5% of phosphorus and 3% of silicon necessary for phytoplankton growth for the China Seas. This demonstrates regenerated nutrients in water column and sediments and nutrients transport fluxes between the China Seas and open ocean play an important role for phytoplankton growth. Atmospheric deposition may be another important source of nutrients for the China Seas.

  20. The herbicide Glyphosate affects nitrification in the Elbe estuary, Germany

    Science.gov (United States)

    Sanders, Tina; Lassen, Stephan

    2015-04-01

    The Elbe River is one of the biggest European rivers discharging into the North Sea. It also transports high amounts of nutrients and pollutants like pesticides. Important source regions of both nutrients and pollutants are located within the river catchment, which is dominated by agricultural land-use. From these agricultural soils, pesticides can be carried via the river and estuary into the North Sea. Glyphosate (N-(phosphonomethyl) glycine) is the most commonly used herbicide worldwide and mainly used to regulate unwanted plant growth and for the expedition of crop ripening. In Germany, ~ 6000 tons of glyphosate are applied yearly in agriculture and private use. Glyphosate is degradable by microorganisms and has a half-life in water of 35 to 60 days. This herbicide specifically inhibits 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), an enzyme that catalyzes the biosynthesis of essential aromatic amino acids in plants, fungi, and bacteria. Nitrifying bacteria, which play an important role in the internal nitrogen cycling in the Elbe estuary, also possess this enzyme. The aim of our study was to quantify the concentration of glyphosate in water and sediment samples of the Elbe to get an overview about relevant environmental levels and to assess the impact of glyphosate on inhibition of nitrifying activities. To quantify the effect of glyphosate on nitrification activity, natural samples as well as pure cultures of Nitrosomonas europea (strain Nm50) were incubated with different concentrations of glyphosate over a period of some weeks. The nitrifying activity was determined according to changes of the nitrite and nitrate concentration as well as the cell number. Glyphosate was detectable in water and sediment samples in the Elbe estuary with up to 5 ppb mainly in the Port of Hamburg region. In both incubation experiments an inhibiting effect of glyphosate on nitrification could be shown. The incubated natural water sample was affected by a glyphosate concentration that was 1000 fold higher than the measured natural levels. The pure culture Nitrosomonas europaea (Nm 50) was more sensitive and was already inhibited by concentrations 10 to 100 fold above the in-situ concentrations. Overall, we find that glyphosate is apparently not as easily degradable as expected, as it can be detected in the water column and sediment of the Elbe estuary in spring and summer. Our results indicate that especially during bacterial growth, the natural nitrifying community can be affected if glyphosate concentrations in the water column increase.

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

    Scientific Electronic Library Online (English)

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

    2012-09-01

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

  2. 2012 Southwest Florida Water Management District (SWFWMD) DTM/Lidar: Lake Manatee

    National Oceanic and Atmospheric Administration, Department of Commerce — Geographic Information System (GIS). Southwest Florida Water Management District (SWFWMD) regularly uses digital topographic information to support regulatory, land...

  3. Pollutant Flux Estimation in an Estuary Comparison between Model and Field Measurements

    Directory of Open Access Journals (Sweden)

    Yen-Chang Chen

    2014-08-01

    Full Text Available This study proposes a framework for estimating pollutant flux in an estuary. An efficient method is applied to estimate the flux of pollutants in an estuary. A gauging station network in the Danshui River estuary is established to measure the data of water quality and discharge based on the efficient method. A boat mounted with an acoustic Doppler profiler (ADP traverses the river along a preselected path that is normal to the streamflow to measure the velocities, water depths and water quality for calculating pollutant flux. To know the characteristics of the estuary and to provide the basis for the pollutant flux estimation model, data of complete tidal cycles is collected. The discharge estimation model applies the maximum velocity and water level to estimate mean velocity and cross-sectional area, respectively. Thus, the pollutant flux of the estuary can be easily computed as the product of the mean velocity, cross-sectional area and pollutant concentration. The good agreement between the observed and estimated pollutant flux of the Danshui River estuary shows that the pollutant measured by the conventional and the efficient methods are not fundamentally different. The proposed method is cost-effective and reliable. It can be used to estimate pollutant flux in an estuary accurately and efficiently.

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Dion, E.P.

    1983-01-01

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

  6. Numerical Model of Pollution Dispersion in the Gour Soozan Estuary – Bandar Abbas, Iran

    Directory of Open Access Journals (Sweden)

    Arefe Emami

    2013-01-01

    Full Text Available Pollution and the dispersion of pollutants are important issues in the environment of rivers and estuaries, being regarded as the major problems in utilizing the surface water globally. Environmentally speaking, the Gour Soozan Estuary suffers from a lot of problems. Arriving at a model for the dispersion of pollution and pollutant particles will therefore provide useful information for future studies in the field of environment and developmental activities in Bandar Abbas. Taking the available field data into account and using Delf3D numerical models, the present study has firstly contended with the hydrodynamic modeling of the estuary; and regarding the obtained hydrodynamic conditions, it has then conducted a two-dimensional modeling of pollution dispersion in the region. The results show that the dispersion of pollution in the cross-sectional area of the estuary has had a rising trend whose concentration gradient does not decline over time. With water flows advancing from the mouth of the estuary toward its end, the dispersion and transfer of pollutant particles will decrease due to the reduction in the range of tidal fluctuations. With releasing pollutant particles in the estuary momentarily, they will gradually leave the estuary through an oscillatory motion over time, being transported to the west of the Persian Gulf and endangering the environment in the west coasts of Bandar Abbas.

  7. Understanding the fate of iron in a modern temperate estuary: Leirarvogur, Iceland

    International Nuclear Information System (INIS)

    Highlights: ? Fluvial Fe (aq) and Fe (total) concentrations drop upon mixing with seawater in estuaries. ? The majority of Fe in estuaries is lost in the bay-head delta. ? Our results suggest that the bay-head delta is a key location in Fe-mineral formation. ? Isotopic variation in estuarine waters may play a role in the formation of Fe-minerals. - Abstract: Fluvial dissolved Fe concentrations decrease upon mixing with seawater, resulting in the formation of Fe-floccules. However, a clear understanding of the fate of these floccules has yet to be established. Assessing how tidal processes affect the formation of Fe-colloids in the Leirarvogur estuary, SW Iceland, is an important step in understanding the formation and potential deposition of estuarine Fe-rich minerals within this estuarine system. The Leirarvogur estuary drains predominately Fe-rich basalt, increasing the likelihood of detecting changes in Fe-phases. Fluvial waters and local lake waters that drain into the estuary were compared and the effects of seasonal changes were considered, in an attempt to understand how varying end-members and external factors play a role in Fe-rich mineral formation. Aqueous and colloidal Fe concentrations were found to be greater towards the head of the Leirarvogur estuary, suggesting that potential Fe-rich minerals and complexes are forming at sites of fluvial input. Increasing suspended colloidal Fe towards the estuary mouth suggests that Fe-colloids are readily trts that Fe-colloids are readily transported seaward.

  8. Understanding the fate of iron in a modern temperate estuary: Leirarvogur, Iceland

    Energy Technology Data Exchange (ETDEWEB)

    Byrne, Gemma M., E-mail: gmbyrne@liverpool.ac.uk [Department of Earth and Ocean Sciences, School of Environmental Science, University of Liverpool, Liverpool L69 3GP (United Kingdom); Worden, Richard H.; Hodgson, David M. [Department of Earth and Ocean Sciences, School of Environmental Science, University of Liverpool, Liverpool L69 3GP (United Kingdom); Polya, David A.; Lythgoe, Paul R. [School of Earth, Atmosphere and Environmental Sciences, University of Manchester, Manchester M13 9PL (United Kingdom); Barrie, Craig D.; Boyce, Adrian J. [Scottish Universities Environmental Research Centre, Rankine Avenue, East Kilbride, Glasgow G75 0QF (United Kingdom)

    2011-06-15

    Highlights: > Fluvial Fe (aq) and Fe (total) concentrations drop upon mixing with seawater in estuaries. > The majority of Fe in estuaries is lost in the bay-head delta. > Our results suggest that the bay-head delta is a key location in Fe-mineral formation. > Isotopic variation in estuarine waters may play a role in the formation of Fe-minerals. - Abstract: Fluvial dissolved Fe concentrations decrease upon mixing with seawater, resulting in the formation of Fe-floccules. However, a clear understanding of the fate of these floccules has yet to be established. Assessing how tidal processes affect the formation of Fe-colloids in the Leirarvogur estuary, SW Iceland, is an important step in understanding the formation and potential deposition of estuarine Fe-rich minerals within this estuarine system. The Leirarvogur estuary drains predominately Fe-rich basalt, increasing the likelihood of detecting changes in Fe-phases. Fluvial waters and local lake waters that drain into the estuary were compared and the effects of seasonal changes were considered, in an attempt to understand how varying end-members and external factors play a role in Fe-rich mineral formation. Aqueous and colloidal Fe concentrations were found to be greater towards the head of the Leirarvogur estuary, suggesting that potential Fe-rich minerals and complexes are forming at sites of fluvial input. Increasing suspended colloidal Fe towards the estuary mouth suggests that Fe-colloids are readily transported seaward.

  9. Macrobenthic communities of saltpans from the Sado estuary (Portugal)

    Science.gov (United States)

    Amaral, Maria José; Costa, Maria Helena

    1999-07-01

    A 1-year study on the evolution of benthic communities of saltpans from the Sado estuary was carried out in order to evaluate its density, biomass and diversity, and to understand its trophic-dynamic structure under harsh environmental conditions. Physical and chemical parameters of the water column and sediments were also studied. Salinity and redox potential fluctuated sharply. Of eighteen taxa observed, a few occurred in significant numbers Chironomus salinarius (99 %) at crystallisation ponds where Artemia is present in the water column at salinities ranging from 23 to 249 g .L -1, Hydrobia (95 %) at evaporation pond (salinities between 29 and 112 g .L -1), while the reservoir, with salinities from 22 to 45 g .L -1, showed higher diversity nevertheless lower than in the estuary itself. It is colonised all year by Abra ovata, Cerastoderma glaucum, Hedistes diversicolor, Capitella sp., Microspio mecznikowianus, Mellina palmata, Polydora ciliata, Capitellidae and Microdeutopus gryllotalpa. The diversity of macrobenthic communities decreases with increasing salinity. Among trophic dynamic groups, surface detritivores burrowers, which are present at 85 % of the samples, are the dominant group at evaporation and crystallisation ponds and appears as an isolated group linked to organic matter of sediments and nutrients.

  10. Distribution ofVibrio cholerae in two Florida estuaries.

    Science.gov (United States)

    Hood, M A; Ness, G E; Rodrick, G E; Blake, N J

    1983-04-01

    The distribution ofVibrio cholerae was examined in 2 Florida estuaries, Apalachicola and Tampa Bay.Vibrio cholerae serotype non-01 was the most abundant serotype, being isolated from 45% of the oyster samples, 30% of the sediments, 50% of the waters, and 75% of the blue crabs.Vibrio cholerae serotype 01 was isolated from only one oyster sample. Strong linear correlations betweenV. cholerae and temperature, salinity, or the other physical/chemical parameters measured,Escherichia coli, or fecal coliforms were not observed, but a range of temperatures and salinities appeared relevant to the distribution of the organism. The organism was present in the highest concentrations when salinities were 10‰-25‰ and temperatures were 20‡C-35‡C.In vitro growth curves of 95V. cholerae environmental isolates further supported that 10‰-25‰ was an ideal salinity range for the organisms. The results suggest thatV. cholerae is a widely distributed organism in the nutrient-rich warm waters of the Gulf Coast estuaries. PMID:24221617

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

    Science.gov (United States)

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

    2004-05-01

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

  12. Major hydrogeochemical processes in an acid mine drainage affected estuary.

    Science.gov (United States)

    Asta, Maria P; Calleja, Maria Ll; Pérez-López, Rafael; Auqué, Luis F

    2015-02-15

    This study provides geochemical data with the aim of identifying and quantifying the main processes occurring in an Acid Mine Drainage (AMD) affected estuary. With that purpose, water samples of the Huelva estuary were collected during a tidal half-cycle and ion-ion plots and geochemical modeling were performed to obtain a general conceptual model. Modeling results indicated that the main processes responsible for the hydrochemical evolution of the waters are: (i) the mixing of acid fluvial water with alkaline ocean water; (ii) precipitation of Fe oxyhydroxysulfates (schwertmannite) and hydroxides (ferrihydrite); (iii) precipitation of Al hydroxysulfates (jurbanite) and hydroxides (amorphous Al(OH)3); (iv) dissolution of calcite; and (v) dissolution of gypsum. All these processes, thermodynamically feasible in the light of their calculated saturation states, were quantified by mass-balance calculations and validated by reaction-path calculations. In addition, sorption processes were deduced by the non-conservative behavior of some elements (e.g., Cu and Zn). PMID:25530015

  13. Monitoring requirements for detecting tidal barrage induced changes to estuary bird populations

    International Nuclear Information System (INIS)

    This study was performed to examine the monitoring requirements for detecting tidal barrage induced changes to estuary bird populations, focussing mainly on the Mersey estuary. The degree of variability in populations between years for a number of species within the Mersey, Dee, Alt and Ribble were ascertained. The number of counts needed each winter, before and after barrage construction, were assessed. The percentage charge detectable for species was predicted. One east coast estuary (the Wash) was investigated for comparison of the effects of influences of severe weather. (UK)

  14. Digestive tube contents of blood cockle (Anadara granosa in a tropical mangrove estuary in Malaysia

    Directory of Open Access Journals (Sweden)

    Tatsuya Yurimoto

    2014-08-01

    Full Text Available This study was carried out to clarify the feeding biology of the blood cockle (Anadara granosa. We collected blood cockles from 8 stations in the Matang mangrove estuary of Malaysia in July and August 2010. The digestive tube contents of the specimens were stained with Congo red and observed under a light microscope. The results showed blood cockles take in particles containing cellulose as well as phytoplankton such as diatoms. As blood cockles in estuaries are known to exhibit cellulolytic enzyme activity in their digestive gland, the present results indicate blood cockles in estuaries feed on litter supplied from mangrove forests and terrestrial plants.

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

    International Nuclear Information System (INIS)

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

  16. Southwest British Columbia natural gas supply and deliverability: Discussion paper

    International Nuclear Information System (INIS)

    A review is presented of energy in British Columbia, the role of natural gas, and options available to enhance gas supply security in the province's most densely populated area, the southwest. British Columbia has abundant natural gas supplies, and production exceeds domestic demand. In 1992, natural gas supplied ca 25% of total provincial end-use energy requirements, but this share is expected to rise to 30% by 2015. Although some say that the province's natural gas production and transmission system should serve only domestic needs, this would have significant negative impacts. Domestic gas supply policy allows gas consumers to contract their own supplies, but contract security is required. Provincial guidelines allow demand-side programs to compete with supply sources to ensure that the resource profile is achieved at least cost. In the southwest, natural gas demand is projected to increase from 189 PJ in 1991 to 262 PJ by 2005. Most gas supplied to this region comes from northeast British Columbia through pipelines that are generally fully contracted. Short-term deliverability can be a problem, especially in peak winter demand periods. The gas industry's contingency plans for shortages are outlined and alternatives to enhance deliverability to the southwest are assessed, including storage, expansion of the pipeline system, supply curtailment, and peaking supply contracts. Aspects of provincial natural gas planning are discussed, including security of supply and deussed, including security of supply and deliverability, economic and environmental impacts, consumer costs, safety, and the public interest. A least-cost option for enhancing deliverability (underground storage and an additional liquefied natural gas plant) is estimated to cost consumers $3.69/GJ over 20 years. 9 figs., 1 tab

  17. Rocky desertification in Southwest China: Impacts, causes, and restoration

    Science.gov (United States)

    Jiang, Zhongcheng; Lian, Yanqing; Qin, Xiaoqun

    2014-05-01

    Rocky desertification, which is relatively less well known than desertification, refers to the processes and human activities that transform a karst area covered by vegetation and soil into a rocky landscape. It has occurred in various countries and regions, including the European Mediterranean and Dinaric Karst regions of the Balkan Peninsula, Southwest China on a large scale, and alarmingly, even in tropical rainforests such as Haiti and Barbados, and has had tremendous negative impacts to the environment and social and economic conditions at local and regional scales. The goal of this paper is to provide a thorough review of the impacts, causes, and restoration measures of rocky desertification based on decades of studies in the southwest karst area of China and reviews of studies in Europe and other parts of the world. The low soil formation rate and high permeability of carbonate rocks create a fragile and vulnerable environment that is susceptible to deforestation and soil erosion. Other natural processes related to hydrology and ecology could exacerbate rocky desertification. However, disturbances from a wide variety of human activities are ultimately responsible for rocky desertification wherever it has occurred. This review shows that reforestation can be successful in Southwest China and even in the Dinaric Karst region when the land, people, water, and other resources are managed cohesively. However, new challenges may arise as more frequent droughts and extreme floods induced by global climate change and variability may slow the recovery process or even expand rocky desertification. This review is intended to bring attention to this challenging issue and provide information needed to advance research and engineering practices to combat rocky desertification and to aid in sustainable development.

  18. Variations of sediment toxicity in a tidal Estuary: A case study of the South Passage, Changjiang (Yangtze) Estuary.

    Science.gov (United States)

    Gao, Jinjuan; Shi, Huahong; Dai, Zhijun; Mei, Xuefei

    2015-06-01

    Sediments in estuaries, especially those containing a large reservoir of contaminants released from urban and industrial activities, have had great impacts on benthic fauna and associated species. A better understanding of the toxicity of contaminants in estuarine sediments is of great significance to ecological assessments. Here, based on the collected sediments from neap to spring tides in the South Passage, Changjiang Estuary, the toxicity of the sediments was first studied using the frog embryo teratogenesis assay-Xenopus (FETAX). The results showed that the extracts of estuarine sediments induced multiple malformations in the embryos and that the phenotypes of malformation had two distinct patterns of variations corresponding to the tidal cycles. The phenotypes in the first pattern were dominated by hypopigmentation and edema of the heart, and the pattern was mainly controlled by fine-grained fractions. The phenotypes in the second pattern were dominated by edema of the heart and enlarged proctodeum, and it was mostly controlled by coarse-grain fractions. The sediment toxicity was higher during the spring and flood tides, which may be influenced by the grain size and sediment resuspension. Furthermore, obvious periodicities existed in the changes of the percentages of hatching (14-16h and 6h), enlarged proctodeum (15-18h), and bent tail (5-7h) due to the influence of tidal cycles. Moreover, our results also suggested that FETAX is an appropriate cost-effective biological monitoring tool to assess estuarine ecological health in contaminated sediments. PMID:25635945

  19. Geochemical methods applied to uranium exploration in southwest Baffin Island

    International Nuclear Information System (INIS)

    A geochemical orientation survey was undertaken in an area in southwest Baffin Island. A methodology was established for a future reconnaissance geochemical program using lake samples. Mineralogical and chemical studies of known radioactive occurrences, combined with detailed sampling of secondary environment media in the vicinity of the showings, indicate that uranium is the most significant pathfinder, despite considerable enrichment of other metals in the uraniferous rocks. Significant geochemical patterns produced by uranium in lake waters and uranium in lake sediments have been obtained, but their relative usefulness depends on the distribution of carbonate bedrock. The base metal potential of the area was examined in some detail and found to be significant. (author)

  20. BATHY: 10 m bathymetric contours for the Southwest Washington Study area

    U.S. Geological Survey, Department of the Interior — Two 21-day field operations were conducted in 1997 and 1998 in the estuaries and on the inner continental shelf off the northern Oregon and southern Washington...

  1. The bathymetric distribution of intertidal eelgrass Zostera marina L. in three coastal estuaries of Oregon

    Science.gov (United States)

    Distributions of native eelgrass Zostera marina L. within the intertidal and shallow subtidal zones of three Oregon coastal estuaries (Tillamook, Yaquina, and Alsea) were determined by digital classification of aerial color infrared (CIR) orthophotographs. Stratified random surv...

  2. Environmental Conditions in northern Gulf of Mexico Estuaries: before and after the BP Oil Spill

    Science.gov (United States)

    This presentation provides a summary of ecological condition and sediment chemistry data for northern Gulf of Mexico estuaries that were exposed to oil and oil-related contaminants from the BP Oil Spill. ...

  3. Circulation and mixing process in Vasishta-Godavari estuary, east coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Kumar, A.R.S.; Murty, T.V.R.; Rao, M.M.M.; Rao, V.R.; Reddy, B.S.R.

    2005-01-01

    content gradually from September to January. Model studies based on these observations may be more useful in understanding the basic mechanisms involved in circulation, mixing and flushing aspects of the estuary...

  4. Fin Fish Biodiversity Of A Tropical Sal Estuary, Goa, West Coast Of India

    Directory of Open Access Journals (Sweden)

    Nandadeep U. Fal Dessai

    2013-09-01

    Full Text Available Sal estuary represents rich biodiversity because of the heavy rains during the south west monsoon and lack of any industrial development along the banks of the river. Attempt was made to survey the fin fish biodiversity along the estuary to fulfill the lack of adequate information regarding estuarine fisheries. Hydrological parameters were analysed during the study period and found to be highly influencing. Fishes were caught near shore by using gill nets and cast nets. About 35 fin fishes were recorded belonging to 28 families. The distribution varies according to the environmental conditions. Some of the important fin fishes found in this estuary are Mugil cephalus, Gerres filamentosus, Sillago sihama, Etroplus suratensis, Arius arius, Lutjanus argentimaculatus, Acanthopagrus berda and Lobotes surinamensis. Some of the fresh water species are also observed in the Sal river. In future, Industrialization along the bank of the estuary may threaten the species diversity and need necessary laws for conservation of biodiversity

  5. Heterotrophic utilization of extracellular products of phytoplankton in a tropical estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Gomes, H.; Pant, A; Goes, J.I.; Parulekar, A

    1991-01-01

    Bacterial uptake of algal exudates has been estimated in a tropical estuary, Dona Paula, Goa, India, where the seasonal fluctuations in hydrographic and nutrient parameters as well as dissolved organic matter concentrations and phytoplankton species...

  6. 76 FR 8345 - Endangered and Threatened Species; Recovery Plan Module for Columbia River Estuary Salmon and...

    Science.gov (United States)

    2011-02-14

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

  7. Ambiguities in the classification of cochin estuary, West coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Shivaprasad, A; Vinita, J.; Revichandran, C.; Manoj, N; Jayalakshmy, K.V.; Muraleedharan, K.R.

    2013-01-01

    Cochin Estuary is a unique complex system along Indian coastline with a widespread area at the upstream. The fluctuations in salinity are of extreme kind ranging from entirely riverine to entirely saline. The high runoff months are characterized...

  8. San Francisco Estuary Midwinter Waterfowl Survey: 2012 Survey Results and Trend Analysis (1981-2012)

    US Fish and Wildlife Service, Department of the Interior — This report provides results of the 2012 San Francisco Estuary Midwinter Waterfowl Survey and presents an analysis of trends in waterfowl counts from 19812012. The...

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

    Science.gov (United States)

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

    2009-03-01

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

  10. Development and validation of a MODIS colored dissolved organic matter (CDOM) algorithm in northwest Florida estuaries

    Science.gov (United States)

    Satellite remote sensing provides synoptic and frequent monitoring of water quality parameters that aids in determining the health of aquatic ecosystems and the development of effective management strategies. Northwest Florida estuaries are classified as optically-complex, or wat...

  11. An analysis of MODIS algorithms for surface salinity and dissolved organic carbon in northwest Florida estuaries

    Science.gov (United States)

    Synoptic and frequent monitoring of water quality parameters from satellite is useful for determining the health of aquatic ecosystems and development of effective management strategies. Northwest Florida estuaries are classified as optically-complex, or waters influenced by chlo...

  12. Stable isotopes of carbon and nitrogen in suspended matter and sediments from the Godavari estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Sarma, V.V.S.S.; Arya, J.; Subbaiah, Ch.V.; Naidu, S.A.; Gawade, L.; PraveenKumar, P.; Reddy, N.P.C.

    2012-01-01

    Spatial distribution of the carbon and nitrogen content and their isotopic enrichment in suspended matter and sediments were measured in the Godavari estuary to identify the sources and transformation mechanism of organic matter. Significant...

  13. Computation of dilution discharge and mean concentration of effluents in Beypore Estuary, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    DineshKumar, P.K.; Josanto, V.; Sankaranarayanan, V.N.

    1995-01-01

    Tide dominated Beypore estuary along the west coast of India was studied to estimate the mean flow available for diluting the conservative effluents based on the distribution of ambient salinity as a guide through one dimensional analysis...

  14. Environmental fate of fungicides and other current-use pesticides in a central California estuary.

    Science.gov (United States)

    Smalling, Kelly L; Kuivila, Kathryn M; Orlando, James L; Phillips, Bryn M; Anderson, Brian S; Siegler, Katie; Hunt, John W; Hamilton, Mary

    2013-08-15

    The current study documents the fate of current-use pesticides in an agriculturally-dominated central California coastal estuary by focusing on the occurrence in water, sediment and tissue of resident aquatic organisms. Three fungicides (azoxystrobin, boscalid, and pyraclostrobin), one herbicide (propyzamide) and two organophosphate insecticides (chlorpyrifos and diazinon) were detected frequently. Dissolved pesticide concentrations in the estuary corresponded to the timing of application while bed sediment pesticide concentrations correlated with the distance from potential sources. Fungicides and insecticides were detected frequently in fish and invertebrates collected near the mouth of the estuary and the contaminant profiles differed from the sediment and water collected. This is the first study to document the occurrence of many current-use pesticides, including fungicides, in tissue. Limited information is available on the uptake, accumulation and effects of current-use pesticides on non-target organisms. Additional data are needed to understand the impacts of pesticides, especially in small agriculturally-dominated estuaries. PMID:23790458

  15. Does mining pollution affect foraminiferal distribution in Mandovi estuary, Goa, India?

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.; Nayak, G.N.; Naik, S.

    2002-01-01

    A total of 10 surface sediment samples were collected in the premonsoon season in 1990 from the Mandovi estuary, Goa, India. Study revealed presence of 14 species of foraminifera. The foraminiferal data is of special significance because the same...

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

    Digital Repository Service at National Institute of Oceanography (India)

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

    2012-01-01

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

  17. Speciation and behaviour of Cd, Pb and Cu in Zuari Estuary, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    George, M.D.

    1993-01-01

    Dissolved labile and nonlabile forms of Cd, Pb and Cu in Zuari Estuary, Goa, India measured for a period of 14 months showed lowest concentrations during the SW monsoon (June-September) while maximum concentrations were observed during...

  18. Predicting submerged aquatic vegetation occurence (SAV) in a Great Lakes estuary

    Science.gov (United States)

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

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

    Science.gov (United States)

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

  20. Organotins in the sediments of the Zuari estuary, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Jadhav, S.; Bhosle, N.B.; Massanisso, P.; Morabito, R.

    2009-01-01

    . They have been known to be extremely poisonous to mollusk fishery resources (oysters, clams, etc.). Contamination of Zuari estuary (Goa, India) sediments was assessed by quantitative determination of butyltins and phenyltins by using GC-MS using the electron...

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

    Digital Repository Service at National Institute of Oceanography (India)

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

    1996-01-01

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

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

    International Nuclear Information System (INIS)

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

  3. National Status and Trends: Bioeffects Assessment Program, St Lucie Estuary Summary Database (2001-2004)

    National Oceanic and Atmospheric Administration, Department of Commerce — The foundation of this study was based on a sediment quality triad (SQT) approach with a probabilistic sampling design, which characterized the estuary in terms of...

  4. 77 FR 15722 - Takes of Marine Mammals Incidental to Specified Activities; Russian River Estuary Management...

    Science.gov (United States)

    2012-03-16

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

  5. A note on the comparative turbidity of some estuaries of the Americas

    Science.gov (United States)

    Uncles, R.J.; Smith, R.E.

    2005-01-01

    Field data from 27 estuaries of the Americas are used to show that, in broad terms, there is a large difference in turbidity between the analyzed east and west-coast estuaries and that tidal range and tidal length have an important influence on that turbidity. Generic, numerical sediment-transport modeling is used to illustrate this influence, which exists over a range of space scales from, e.g., the Rogue River Estuary (few km, few mg l-1) to the Bay of Fundy (hundreds of km, few g l-1). The difference in Pacific and Atlantic seaboard estuarine turbidity for the analyzed estuaries is ultimately related to the broad-scale geomorphology of the two continents.

  6. CREEK Project's Oyster Biomass Database for Eight Creeks in the North Inlet Estuary, South Carolina

    Baruch Institute for Marine and Coastal Sciences, Univ of South Carolina — A group of eight tidal creeks dominated by oysters, Crassostrea virginica, in North Inlet Estuary, South Carolina, USA were studied using a replicated BACI (Before...

  7. A study on the zooplankton of the Burhabalanga Estuary, Orissa Coast

    Digital Repository Service at National Institute of Oceanography (India)

    Ramaiah, Neelam; Chatterji, A.; Madhupratap, M.

    1996-01-01

    Annual variations in the zooplankton biomass and composition during 1991-92 were studied from the inshore, mouth and upstream regions of the Burhabalanga Estuary located in the Orissa Coast (India). Zooplankton biomass was maximum at all...

  8. Intra- and inter-seasonal variability of nutrients in a tropical monsoonal estuary (Zuari, India).

    Digital Repository Service at National Institute of Oceanography (India)

    Anand, S.S.; Sardessai, S.; Muthukumar, C.; Mangalaa, K.R.; Sundar, D.; Parab, S.G.; DileepKumar, M.

    2014-01-01

    discharges in transporting mining effluents from the river basin. Results also suggest that extrapolation of controlling factors of biogeochemical variables at a fixed location to the entire estuary is untenable since the relative dominance of forcings vary...

  9. Sources, distribution and preservation of organic matter in a tropical estuary (Godavari, India)

    Digital Repository Service at National Institute of Oceanography (India)

    Krishna; Naidu, S.A.; Subbaiah, Ch.V.; Gawade, L.; Sarma, V.V.S.S.; Reddy, N.P.C.

    2015-01-01

    Major sources and distribution of organic matter (OM) were examined in a tropical monsoonal estuary, the Godavari, using content and isotopic signatures in suspended particulate matter and surface sediments during no-discharge period. The lower (<10...

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

    Digital Repository Service at National Institute of Oceanography (India)

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

    1995-01-01

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

  11. Studies on organic carbon, nitrogen and phosphorous in the sediments of Mandovi Estuary, Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Nasnolkar, C.M.; Shirodkar, P.V.; Singbal, S.Y.S.

    1996-01-01

    Sediment organic carbon, total nitrogen, total phosphorous and hydrography of the overlying waters of the estuarine region in Mandovi Estuary, Goa, India have been studied. The relationship of carbon and nutrients with sediment characteristics...

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

    Science.gov (United States)

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

  13. Geospatial analysis of long-term morphological changes in Cochin estuary, SW coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    DineshKumar, P.K.; Gopinath, G.; Manimurali, R.; Muraleedharan, K.R.

    2014-01-01

    the dynamic processes within the estuary. Observed trends of morphological changes generate concern in the background that the region may continue to remain vulnerable in the coming decades due to development pressures in the adjoining hinterlands...

  14. Freshwater flushing time scales of the Vashishti Estuary, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

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

    1999-01-01

    method indicated that the load retained in the estuary after infinite number of tidal cycles was 44 to 54 times the load introduced per tidal cycles during premonsoon and 47 to 61 times during postmonsoon periods. Calculations on longitudinal diffusion...

  15. Particle-associated bacterial dynamics in a tropical tidal plain (Zuari estuary, India)

    Digital Repository Service at National Institute of Oceanography (India)

    DeSouza, M.J.B.D.; Nair, S.; LokaBharathi, P.A.; Chandramohan, D.

    2003-01-01

    The dynamics of particle-associated bacteria (PAB) in a tropical estuary, Zuari, in Goa on the west coast of India, was studied for a year from September 1997 to October 1998. Bacterial abundance, productivity and enzymatic activities were measured...

  16. The "Southwest Effect" Revisited: An Empirical Analysis of the Effects of Southwest Airlines and JetBlue Airways on Incumbent Airlines from 1993 to 2009

    OpenAIRE

    Steven M. Wu

    2012-01-01

    The expansion of Southwest Airlines and JetBlue Airways has sparked new empirical interest in the effects of low-cost carriers (LCC) on existing airfares. Namely, empirical studies have attempted to capture the threat, or potential competition, of an entrant. This paper examines incumbent airline prices as a result of potential and actual competition from both Southwest Airlines and JetBlue Airways from 1993 to 2009 by analyzing mean airfares as well as price dispersion on incumbent routes. I...

  17. Mangroves and Associated Flora of Vashista and Vainateyam Estuaries, A.P. India

    OpenAIRE

    Narasimha Rao, Geddada Mohan; Prayaga Murty, Pragada

    2010-01-01

    Mangroves are highly productive ecosystems occurs intertidal regions only. Mangroves and associated flora occurring in two major estuaries of Godavari river (India) were studied using transect with 4x4 m2 quadrats and the quadrat samples were analyzed. Seasonal data were collected on environmental, hydrographical and chemical observations from three different stations of the two estuaries. Low values in Secchi depth, salinity and pH were reported during the monsoon season, while higher values...

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

    OpenAIRE

    Fahri; Tamaluddin Syam

    2011-01-01

    Surround a big river estuary coastline has a dynamic characteristic and change along a period of time, because of a natural process and/or it is accelerated by human activities. The surround Sekampung river estuary coastline located in Rawa Sragi area is one of the most dynamic coastlines in southern Lampung Province that has changed significantly from 1959 (as a natural process) to year 1987 (as an accelerated process by human activities) since the government of Indonesia has applied swamp ...

  19. Data on nutrition of amur sturgeon Acipenser schrenckii and kaluga Acipenser dauricus in the Amur estuary

    Directory of Open Access Journals (Sweden)

    Kolobov Vladimir Yurievich

    2013-09-01

    Full Text Available Data on nutrition of Amur sturgeon and kaluga in the Amur estuary are presented for the first time. It is found that the main food of Amur sturgeon consists of polychaetes (75.2 % and mol-luscs (more than 90 %, as crustaceans (71.9 % and fishes (66.2 % are dominant in kaluga food composition. Regional peculiarities of both species feeding in different areas of the Amur estuary are described.

  20. Functional diversity in European estuaries: Relating the composition of fish assemblages to the abiotic environment

    OpenAIRE

    Nicolas, D.; Lobry, J.; Le Pape, O.; Boe?t, P.

    2010-01-01

    Based on a large standardised data set, the present study proposed a meta-analysis to describe general patterns in the functional diversity of estuarine fish assemblage in terms of both number of species and density along the European Atlantic coast. Fish species collected from 31 European estuaries from Portugal to Scotland were allocated to functional groups according to their ecological utilization of estuaries. A clustering analysis was performed to compare the overall functional structur...

  1. Turbidity-induced changes in feeding strategies of fish in estuaries

    OpenAIRE

    Lingen, C. D.; Hecht, T.

    2012-01-01

    ENGLISH ABSTRACT: The aim of this study was to determine the effect of turbidity on the feeding strategies of fish in estuaries. Three species representing different feeding guilds were selected for the investigation. These were Elops machnata (representative piscivore), Pomadasys commefsonnii (a macrobenthivore) and Athefina breviceps (a planktivore). The stomach contents of these fish were examined from a clear and a turbid estuary and some experimental work was carried out on A. brevic8ps ...

  2. Cytotoxic and genotoxic assessment of potentially contaminated sediments from the Sado Estuary

    OpenAIRE

    Pinto, Miguel; Louro, Henriqueta; Costa, Pedro; Costa, Maria Helena; Caeiro, Sandra; Silva, Maria Joa?o

    2011-01-01

    Previous studies have shown that the river Sado Estuary (W Portugal) is highly susceptible to contamination due to anthropogenic activity. In fact, sizable concentrations of metals, pesticides and polycyclic aromatic hydrocarbons have been measured in sediments from various points of the estuary. Those compounds may be absorbed by aquatic species, making it a public health issue when entering the human food chain. The purpose of this study was to assess the cytotoxic and genotoxic...

  3. Temporal variability of chlorophyll-a in the São Vicente estuary

    OpenAIRE

    André Francisco Bucci; Áurea Maria Ciotti; Ricardo Cesar Gonçalves Pollery; Renan de Carvalho; Heitor Cavalcanti de Albuquerque; Leonardo Tomida Spalletti Simões

    2012-01-01

    Estuaries are extremely dynamic environments that are vulnerable to anthropogenic alterations. Thus, monitoring phytoplankton abundances and composition is an essential tool for the prediction of eutrophication and its effects on coastal ecosystems. Phytoplankton biomass, as chlorophyll-a, in the São Vicente estuary (Brazil) varies in response to tidal cycles and seasonal rainfall. Objectives. To present two datasets designed to assess the relationship between chlorophyll-a and changes in wa...

  4. Salt intrusion in multi-channel estuaries: a case study in the Mekong Delta, Vietnam

    Directory of Open Access Journals (Sweden)

    A. D. Nguyen

    2006-04-01

    Full Text Available There is a well-tested theory for the computation of salt intrusion in alluvial estuaries that is fully analytical and predictable, in the sense that it has well-tested analytical equations to predict the mixing behaviour of the estuary based on measurable quantities, such as channel topography, river discharge and tidal characteristics. This theory has been described in a range of publications (Savenije, 1986, 1989, 1993 and a recent book (Savenije, 2005. This theory applies to single-channel topographies and estuaries that demonstrate moderate tidal damping. The Mekong delta is a multi-channel estuary where the tide is damped due to a relatively strong river discharge (in the order of 2000m$^{3}$/s, even during the dry season. As a result the Mekong is a strongly riverine estuary. This paper aims to test if the theory can be applied to such a riverine multi-channel estuary, and to see if possible adjustments or generalisations need to be made. The paper presents salt intrusion measurements that were done by moving boat in 2005, to which the salt intrusion model was calibrated. The theory was expanded to cater for tidal damping. Subsequently the model was validated with observations made at fixed locations over the years 1998 and 1999. Finally it was tested whether the Mekong calibration fits the overall predictive equations derived in other estuaries. The test was successful and led to a slight adjustment of the predictive equation to cater for estuaries that experience a sloping bottom.

  5. Salt intrusion in multi-channel estuaries: a case study in the Mekong Delta, Vietnam

    OpenAIRE

    Nguyen, A. Amp Nbsp D.; Amp Nbsp Savenije, H. Amp Nbsp H.

    2006-01-01

    There is a well-tested theory for the computation of salt intrusion in alluvial estuaries that is fully analytical and predictable, in the sense that it has well-tested analytical equations to predict the mixing behaviour of the estuary based on measurable quantities, such as channel topography, river discharge and tidal characteristics. This theory has been described in a range of publications (Savenije, 1986, 1989, 1993) and a recent book (Savenije, 2005). This theory applies to single-chan...

  6. Spatial distribution of subtidal Nematoda communities along the salinity gradient in southern European estuaries

    Science.gov (United States)

    Adão, Helena; Alves, Ana Sofia; Patrício, Joana; Neto, João Magalhães; Costa, Maria José; Marques, João Carlos

    2009-03-01

    This study investigated the spatial distribution of subtidal nematode communities along the salinity gradients of two Portuguese estuaries exposed to different degrees of anthropogenic stress: the Mira and the Mondego. The nematode communities were mainly composed of Sabatieria, Metachromadora, Daptonema, Anoplostoma, Sphaerolaimus and Terschellingia species, closely resembling the communities of Northern European estuaries. In both estuaries, nematode density and community composition followed the salinity gradient, naturally establishing three distinct estuarine sections: (i) freshwater and oligohaline - characterised by the presence of freshwater nematodes, low nematode density and diversity; (ii) mesohaline - dominated by Terschellingia, Sabatieria and Daptonema, with low total density and diversity; and (iii) polyhaline and euhaline - where nematodes reached the highest density and diversity, and Paracomesoma, Synonchiella, and Odontophora were dominant. Despite the similarities in community composition and total nematode density, the proportion of different nematode feeding types were remarkably different in the two estuaries. In Mira, selective deposit feeders were dominant in the oligohaline section, while non-selective deposit feeders were dominant in the other sections. On the contrary, in the Mondego estuary, epigrowth-feeders and omnivores/predators were dominant in the freshwater sections and in the euhaline sector of the southern arm. Differences observed along each estuarine gradient were much stronger than overall differences between the two estuaries. In the Mondego estuary, the influence of anthropogenic stressors seemed not to be relevant in determining the nematodes' spatial distribution patterns, therefore suggesting that mesoscale variability responded essentially to natural stressors, characteristic of estuarine gradients. Nevertheless, the proportion of the different feeding types was different between the two estuaries, indicating that the response of nematode feeding guilds is able to reflect anthropogenic-induced stress and can be useful in assessing biological quality in transitional waters ecosystems.

  7. An introduction to the San Francisco Estuary tidal wetlands restoration series

    OpenAIRE

    Brown, Larry R.

    2003-01-01

    Restoration of tidal wetlands may provide an important tool for improving ecological health and water management for beneficial uses of the San Francisco Estuary (hereafter ?Estuary?). Given the large losses of tidal wetlands from San Francisco Bay and the Sacramento-San Joaquin Delta in the last 150 years, it seems logical to assume that restoring tidal wetlands will have benefits for a variety of aquatic and terrestrial native species that have declined during the same time period. However,...

  8. Effects of an increasing filter feeder stock on larval abundance in the Oosterschelde estuary (SW Netherlands)

    OpenAIRE

    Troost, K.; Gelderman, E. A. C.; Kamermans, P.; Smaal, A. C.; Wolff, W.

    2009-01-01

    Predation by adult bivalves on bivalve larvae has been suggested to reduce larval abundance in areas with high bivalve filter-feeder biomass. Although the occurrence of larviphagy is well-studied in the laboratory, its effects in the field have scarcely been studied. We studied larviphagy at different spatial scales in the Oosterschelde estuary. On the scale of individuals, we confirmed that larviphagy occurs in Crassostrea gigas and Mytilus edulis in the Oosterschelde estuary, by examining s...

  9. Plutonium in Atlantic coastal estuaries in the southeastern United States of America

    International Nuclear Information System (INIS)

    A survey was made to begin to provide baseline information on the plutonium distribution of representative estuarine and coastal areas of the southeastern United States of America. Sediments and marsh grass (Spartina) were collected and analysed from three locations within a tidal marsh. In the three estuaries (Savannah, Neuse and Newport) the suspended particulate matter (1?m and greater) was filtered from waters with different salinities and the plutonium content of the particulates determined. The Savannah river estuary, in addition to fall-out plutonium, has received up to 0.3Ci of plutonium from the Savannah River Plant (SRP) of the US Energy Research and Development Administration. The SRP plutonium has a variable isotopic composition that can influence plutonium isotopic ratios in the estuarine system. The other estuaries do not have nuclear installations upstream. Plutonium contents in surface marsh sediment from the Savannah River estuary are lower than those found in nearby bay sediments. In fact, total plutonium concentrations of sediments showed increases from the upper to lower portions of the estuary; however, higher contributions of 238Pu in the upper portions indicate that releases from the Savannah River Plant do contribute plutonium to the Savannah river estuary. Plutonium concentrations in Spartina were less than 10fCi/g dry weight but are higher than plutonium contents of terrestrial plants (238Pu to the total plutonium activities in the sediment and the Spartina. Plutonium concentrations were about three times higher in the Newport river estuary than in the Neuse and Savannah river estuaries. (author)

  10. Nutrient behavior in 2 contrasting scottish estuaries, the Forth and Tay

    OpenAIRE

    Balls, Pw

    1992-01-01

    The distribution and behaviour of nutrients (nitrate, nitrite, ammonia, silicate and phosphate) have been examined over the course of a year in two major Scottish estuaries, the Forth and Tay. Maximum concentrations of nitrate and silicate in both estuaries occur in winter, when mixing is conservative. By contrast maximum phosphate, ammonia and nitrite concentrations (notably in the Forth) are observed in summer, these are related to lower oxygen concentrations both within the water column an...

  11. Pacific oysters in Dutch estuaries : causes of success and consequences for native bivalves

    OpenAIRE

    Troost, Karin,

    2009-01-01

    Nowadays many non-indigenous species are found in the Netherlands. Among the most successful is the Pacific oyster (Crassostrea gigas). Since its deliberate introduction in 1964 it has been spreading rapidly throughout Dutch estuaries. It became clear that the expansion of extensive oyster beds could have a large impact on Dutch estuaries and indigenous species, especially bivalves such as the cockle (Cerastoderma edule) and mussel (Mytilus edulis). How the oyster managed to establish itself ...

  12. Estuary planning and management in Portugal: sharing local boundaries for water resources management

    OpenAIRE

    Fidélis, Teresa; Carvalho, Teresa

    2013-01-01

    Estuaries concentrate complex and often conflicting sets of natural, economic and social resources and activities bringing multiple challenges to institutional frameworks, planning and management approaches as well as governance practices dedicated to their protection, maintenance and resilience. Portugal has recently adopted a new set of estuary plans of regulatory nature, which combine the perspective of water resources management with that of land-use management. This paper explores the co...

  13. MCTTFA applied to differential biomonitoring in Sado estuary region

    International Nuclear Information System (INIS)

    Transplants of the epiphytic lichen Parmelia sulcata were suspended in nylon bags within a rectangle of 15 km wide and 25 km long on a grid 2.5 km x 2.5 km in the Sado estuary region. The transplants were oriented towards the wind (F) and opposing the wind (T) and were collected after 3, 6 and 9 months of exposure. Samples were analyzed by INAA and PIXE. Source identification was made by Monte Carlo Target Transformation Factor Analysis (MCTTFA) using three different combinations of data (all data, F data and T data). Five factors were identified for all the combinations performed. For two factors, F and T differentiation was observed. (author)

  14. Map similarity measurement and its application to the Sado estuary

    Directory of Open Access Journals (Sweden)

    Sandra Caeiro

    2003-06-01

    Full Text Available In the past thirty years GIS technology has progressed from computer mapping to spatial database management, and more recently, to quantitative map analysis and modeling. However, most applications still rely on visual analysis for determining similarity within and among maps. The aim of this study is to compare maps of homogenous areas computed from estuarine sediment characterization indicators, using different approaches. These maps were defined using three different interpolation methods. Different Kappa statistics, visual map overlays or components of agreement and disagreement due to chance, quantity and location were used for single cell and/or neighborhood (hard and soft map comparison. Although the three methods were computed with different statistical techniques, their results are similar, supporting the choice of any of the methods as equivalent and thus of equal value to be used as management units of the estuary. Hence the significance of choosing one of the methods is reduced.

  15. Nutrient budgets for large Chinese estuaries and embayment

    Directory of Open Access Journals (Sweden)

    S. M. Liu

    2009-01-01

    Full Text Available Nutrient concentrations among the Chinese rivers and bays vary 10–75 fold depending on nutrient elements. The silicic acid levels in South China rivers are higher than those from North China rivers and the yields of dissolved silicate increased from the north to the south of China, indicating the effect of climate on weathering. The nutrient levels in Chinese rivers are higher than those from the large and less-disturbed world rivers such as Amazon and Zaire, but comparable to the values for European and North American polluted and eutrophic rivers like the Loire and Po. This may be ascribed to both of extensive leaching and influences from agricultural and domestic activities over the drainage basins of Chinese rivers. DIN:PO3?4 ratios in most of Chinese rivers and bays are higher (up to 2800 than the other rivers in the world. The atomic ratios of DIN to PO43? in the major Chinese rivers and embayment decrease in exponential trend with increase in the atomic ratios of PO43? to Si(OH4, indicating that primary production in coastal environments changes with the nutrients transport when the urbanization develops to a certain extent, and the potential limited nutrient elements can be changed from phosphorus to nitrogen limitation, which can modify aquatic food webs and then the ocean ecosystem.

    A simple steady-state mass-balance box model was employed. The output shows that the estuaries and embayment behave as a sink or source of nutrients. For the major Chinese estuaries, both residual and mixing flow transport nutrients off the estuaries, and nutrient transport fluxes in summer is 3–4 fold that in winter except comparable for NH4+. These fluxes are 1.0–1.7 fold that estimated by timing riverine nutrient concentrations and freshwater discharge. For the major Chinese embayment, nutrient elements are transported to China Seas except PO43? and Si(OH4 in Sanggou Bay and Jiaozhou Bay. Seasonally, nutrients transport fluxes off the bays in the summer are 2.2–7.0 fold that in the winter. In the embayment, the exchange flow dominated the water budgets, resulting in average system salinity approaching the China seas salinity where river discharge is limited. The major Chinese estuaries and embayment transport 1.0–3.1% of nitrogen, 0.2–0.5% of phosphorus and 3% of silicon necessary for phytoplankton growth for the China Seas. This demonstrates regenerated nutrients in water column and sediments and nutrients transport fluxes between the China Seas and open ocean play an important role for phytoplankton growth. Atmospheric deposition may be another important source of nutrients for the China Seas.

  16. Guidelines for determining inputs of inorganic contaminants into estuaries

    International Nuclear Information System (INIS)

    This publication describes sampling and sample preparation procedures suitable to obtain unpolluted samples for the purpose of determining river inputs of inorganic pollutants into estuaries. Emphasis is placed on heavy metal pollutants but procedures are suitable, with appropriate modifications for other inorganic pollutants. For example, the collection of samples for mercury may require modifications of handling procedures. River water samples are collected at the most down-river point where no estuarine influences effect results. Samples are collected using a peristaltic pump and separated into aqueous and particulate phases for pollutant analysis. As is the case of all trace pollutant analyses, meticulous care is required to prevent pollution of the sample and in addition to the precautions described in this method, great personal attention is required to minimize sample handling, pollution by smoke, hands, hair, dust, talc from gloves, etc., and to avoid all contact of the samples and reagents with skin and metallic objects. 1 ref., 3 figs, 1 tab

  17. CO2 air-sea fluxes across the Portuguese estuaries Tagus and Sado

    Science.gov (United States)

    Oliveira, A. P.; Cabeçadas, G.; Nogueira, M.

    2009-04-01

    Generally, estuaries and proximal shelves under the direct influence of river runoff and large inputs of organic matter are mostly heterotrophic and, therefore, act as a carbon source. In this context the CO2 dynamics in Tagus and Sado estuaries (SW Portugal) was studied under two different climate and hydrological situations. These moderately productive mesotidal coastal-plain lagoon-type estuaries, localised in the center of Portugal and distant 30-40 km apart, present quite different freshwater inflows, surface areas and water residence times. A study performed in 2001 revealed that the magnitude of CO2 fluxes in the two estuarine systems varied seasonally. CO2 emissions during the huge rainfall winter were similar in both estuaries, reaching a mean value of ~50 mmol m-2 d-1, while in spring emissions from Sado were ~6 times higher then Tagus ones, attaining a mean value of 62 mmol m-2 d-1. Nevertheless, in both sampling periods, Sado estuary showed, within the upper estuary (salinity

  18. Movements and residency of juvenile white steenbras Lithognathus lithognathus in a range of contrasting estuaries

    Science.gov (United States)

    Bennett, Rhett H.; Cowley, Paul D.; Childs, Amber-Robyn; Næsje, Tor F.

    2015-01-01

    Acoustic telemetry was used to assess estuarine area use and movements of an overexploited, endemic fishery species in three South African estuaries; two permanently open systems with contrasting salinity gradients and an intermittently open system. Forty juvenile white steenbras Lithognathus lithognathus (215-379 mm FL) were surgically equipped with acoustic transmitters and tracked for up to 355 days. Tagged fish exhibited high levels of site fidelity and long-term residency within each estuary. Most of their time was spent in the lower reaches of all three estuaries and hypersalinity restricted movements into the upper reaches of the freshwater-deprived estuary. All tagged fish exhibited a distinct diel movement pattern. Most individuals (91%) in the two permanently open estuaries also exhibited a tidal-associated pattern, which comprised mainly small-scale (tens to hundreds of metres) transverse movements between deep channels and shallow banks. Observed behaviour was consistent across a range of estuary sizes, types and physico-chemical conditions. This study has identified critical habitats for juvenile white steenbras across a range of estuarine environments. Estuarine management initiatives need to consider these critical habitats, in order to enhance abundance of juveniles and ultimately recruitment to the marine (adult) population.

  19. Worldwide patterns of fish biodiversity in estuaries: Effect of global vs. local factors

    Science.gov (United States)

    Pasquaud, Stéphanie; Vasconcelos, Rita P.; França, Susana; Henriques, Sofia; Costa, Maria José; Cabral, Henrique

    2015-03-01

    The main ecological patterns and the functioning of estuarine ecosystems are difficult to evaluate due to natural and human induced complexity and variability. Broad geographical approaches appear particularly useful. This study tested, at a worldwide scale, the influence of global and local variables in fish species richness in estuaries, aiming to determine the latitudinal pattern of species richness, and patterns which could be driven by local features such as estuary area, estuary mouth width, river flow and intertidal area. Seventy one estuarine systems were considered with data obtained from the literature and geographical information system. Correlation tests and generalized linear models (GLM) were used in data analyses. Species richness varied from 23 to 153 fish species. GLM results showed that estuary area was the most important factor explaining species richness, followed by latitude and mouth width. Species richness increased towards the equator, and higher values were found in larger estuaries and with a wide mouth. All these trends showed a high variability. A larger estuary area probably reflects a higher diversity of habitats and/or productivity, which are key features for estuarine ecosystem functioning and biota. The mouth width effect is particularly notorious for marine and diadromous fish species, enhancing connectivity between marine and freshwater realms. The effects of river flow and intertidal area on the fish species richness appear to be less evident. These two factors may have a marked influence in the trophic structure of fish assemblages.

  20. Migration dynamics of clupeoids in the Schelde estuary: a stable isotope approach

    DEFF Research Database (Denmark)

    Guelinckx, J.; Maes, J.

    2006-01-01

    Large numbers of young of the year herring (Clupea harengus L.) and sprat (Sprattus sprattus (L.)) typically enter and remain within North Sea estuaries during the winter months. The main purpose of this study was to examine their migration dynamics between the North Sea and the Schelde estuary using C and N stable isotopes. Prior to this,  stomach contents were used to verify the isotopic differences between the food sources at the sampling stations. From May 2000 to April 2001 fish were collected monthly in the upper and lower estuary. Muscle tissue and stomach contents were analyzed for d13C and d15N using an EA-IRMS. Based on the stomach contents, it was demonstrated that d15N could not be used as a tracer for fish migration because the longitudinal estuarine d15N gradient had reversed completely during autumn. The d13C gradient, however, was found to be reliable for studying fish movement in the Schelde estuary. Seasonal movements of clupeoids in the Schelde estuary were analyzed by separating the temporal abundance patterns into migration groups based on their muscle isotopic composition. Immigration and emigration seem to occur continuously throughout the year. Most exchange occurred in November. During winter, immigration remained high but gradually decreased. Although the herring and sprat abundance further declined in the estuary during February and March, large seaward emigration was not fully demonstrated. As temporal overlap between immigration and emigration is concluded the results support the hypothesis that migration to estuarine nurseries is individually based.

  1. Optical changes in a eutrophic estuary during reduced nutrient loadings

    DEFF Research Database (Denmark)

    Pedersen, Troels MØller; Sand-Jensen, Kaj

    2014-01-01

    Loss of water clarity is one of the consequences of coastal eutrophication. Efforts have therefore been made to reduce external nutrient loadings of coastal waters. This paper documents improvements to water clarity between 1985 and 2008–2009 at four stations in the microtidal estuary Roskilde Fjord and find significant relationships to freshwater nutrient loadings. The paper then investigates to which extent changes in phytoplankton biomass (chlorophyll a (Chl a)), non-algal particulate organic matter (POM*), and residual attenuation in the water (K b), respectively, can account for this optical improvement. Vertical light attenuation (K d) declined, on average, by 34 %, accompanying a 71 % reduction of Chl a and an 80 % reduction of POM*. Residual attenuation declined by 26 % over the period in accordance with a measured 34 % decline of dissolved organic nitrogen. Analysis of simultaneous changes in light attenuation and Secchi depth also suggested a reduction of the scatter-to-absorption ratio over time. Considering the stronger reductions of particle concentrations than dissolved organic matter, the contribution of residual attenuation to vertical attenuation increased from 54 to 74 % in 1985 to 78 to 85 % in 2008–2009. Overall, efforts to reduce nutrient loading and improve water clarity appeared to have had a larger impact on POM* than on Chl a and colored dissolved organic matter concentrations in the estuary, which can account for the decrease in the scatter-to-absorption ratio. These optical changes lead to larger improvements of Secchi depth than of vertical light attenuation. The consequence of this is an overestimation (0.45–1.48 m) of the predicted increase of potential seagrass depth limits when based on Secchi depth rather than K d

  2. Mathematical simulation of sediment and radionuclide transport in estuaries

    International Nuclear Information System (INIS)

    The finite element model LFESCOT (Flow, Energy, Salinity, Sediment and Contaminant Transport Model) was synthesized under this study to simulate radionuclide transport in estuaries to obtain accurate radionuclide distributions which are affected by these factors: time variance, three-dimensional flow, temperature, salinity, and sediments. Because sediment transport and radionuclide adsorption/desorption depend strongly on sizes or types of sediments, FLESCOT simulates sediment and a sediment-sorbed radionuclide for the total of three sediment-size fractions (or sediment types) of both cohesive and noncohesive sediments. It also calculates changes of estuarine bed conditions, including bed elevation changes due to sediment erosion/deposition, and three-dimensional distributions of three bed sediment sizes and sediment-sorbed radionuclides within the bed. Although the model was synthesized for radionuclide transport, it is general enough to also handle other contaminants such as heavy metals, pesticides, or toxic chemicals. The model was checked for its capability for flow, water surface elevation change, salinity, sediment and radionuclide transport under various simple conditions first, confirming the general validity of the model's computational schemes. These tests also revealed that FLESCOT can use large aspect ratios of computational cells, which are necessary in handling long estuarine study areas. After these simple tests, FLESCOT was applied to the Hudson Rivers, FLESCOT was applied to the Hudson River estuary between Chelsea and the mouth of the river to examine how well the model can predict radionuclide transport through simulating tidally influenced three-dimensional flow, salinity, sediment and radionuclide movements with their interactions

  3. Geologic effects on groundwater salinity and discharge into an estuary

    Science.gov (United States)

    Russonielloa, Christopher J.; Fernandeza, Cristina; Brattonb, John F.; Banaszakc, Joel F.; Krantzc, David E.; Andresd, Scott; Konikowe, Leonard F.; Michaela, Holly A.

    2013-01-01

    Submarine groundwater discharge (SGD) can be an important pathway for transport of nutrients and contaminants to estuaries. A better understanding of the geologic and hydrologic controls on these fluxes is critical for their estimation and management. We examined geologic features, porewater salinity, and SGD rates and patterns at an estuarine study site. Seismic data showed the existence of paleovalleys infilled with estuarine mud and peat that extend hundreds of meters offshore. A low-salinity groundwater plume beneath this low-permeability fill was mapped with continuous resistivity profiling. Extensive direct SGD measurements with seepage meters (n = 551) showed fresh groundwater discharge patterns that correlated well with shallow porewater salinity and the hydrogeophysical framework. Small-scale variability in fresh and saline discharge indicates influence of meter-scale geologic heterogeneity, while site-scale discharge patterns are evidence of the influence of the paleovalley feature. Beneath the paleovalley fill, fresh groundwater flows offshore and mixes with saltwater before discharging along paleovalley flanks. On the adjacent drowned interfluve where low-permeability fill is absent, fresh groundwater discharge is focused at the shoreline. Shallow saltwater exchange was greatest across sandy sediments and where fresh SGD was low. The geologic control of groundwater flowpaths and discharge salinity demonstrated in this work are likely to affect geochemical reactions and the chemical loads delivered by SGD to coastal surface waters. Because similar processes are likely to exist in other estuaries where drowned paleovalleys commonly cross modern shorelines, the existence and implications of complex hydrogeology are important considerations for studies of groundwater fluxes and related management decisions.

  4. Dune Mining and the Nhlabane Estuary, South Africa: the Effect of a Dredger Crossing on the Zoobenthic Community

    International Nuclear Information System (INIS)

    The Nhlabane Estuary, located on the north-east coast of South Africa, is situated in a titanium dune mining lease area. During 1993, a mining dredger and concentrator crossed the middle reaches of the estuary. For this purpose, two berm walls were constructed across the estuary. Two impacts stemmed from the crossing. A series of fine sediment intrusions into the estuary from the berm wall area occurred during late 1993 and early 1994 and caused a rapid decline in benthic densities and number of taxa. Recovery of the affected area was slow and characterized by initial proliferation of opportunistic colonizers. The berm walls, which divided the estuary in half, were kept in place for nearly three years and caused changes in water quality and the benthic community of the upper and lower halves of the estuary. Artificial breaching of the estuary in August 1995 and removal of the berm walls in May 1996 initiated recovery of the estuary. The success of a second dredger crossing, scheduled for January 1999, depends on addressing the mistakes made during the first crossing and on the speed with which the carefully planned crossing operation, berm wall removal and estuary rehabilitation proceed

  5. The Ostracoda (Crustacea) of the Tina Menor estuary (Cantabria, southern Bay of Biscay): Distribution and ecology

    Science.gov (United States)

    Martínez-García, Blanca; Pascual, Ana; Rodríguez-Lázaro, Julio; Martín-Rubio, Maite; Rofes, Juan

    2013-10-01

    Recent ostracods from the Tina Menor estuary (northern Spain, southern Bay of Biscay) have been analysed. Twenty-five species have been identified for the first time, 20 with living individuals during the sampling period. The most abundant species are Leptocythere castanea, Leptocythere porcellanea, Loxoconcha elliptica, Cytherois fischeri, and Hemicytherura hoskini, Leptocythere psammophila and Semicytherura aff. angulata. These species are grouped into four assemblages defining different environments: muddy inner estuary with euryhaline species (L. elliptica); middle estuary with silty sand flats and low marsh environments (L. castanea, L. porcellanea and C. fischeri); sandy outer estuary with marine characteristics (H. hoskini, S. aff. angulata, Leptocythere baltica and L. psammophila); and littoral to inner shelf environment (Caudites calceolatus, H. hoskini and Callistocythere murrayi). In the middle estuary, L. castanea also delimits sandy-silty low marshes, and L. porcellanea and C. fischeri the vegetated ecosystems. Multivariate analyses with the samples and species (cluster Q-type and detrended and canonical correspondence analysis) confirm that ostracod distribution in the Tina Menor estuary is controlled by sediment grain size and by the distance to the mouth of the estuary (associated to salinity). The geographical height in relation with mean tide levels (and therefore with emersion periods) also plays an important role in distribution. The results of this study confirm ostracod validity as tide-level markers due to the presence of C. fischeri below the MHWNT (mean high water neap tide), whereas L. castanea and L. porcellanea are present between the MHWNT and MHW (mean high water) levels. Ostracods can also indicate environmental changes due to human-influenced processes. Abundant individuals of L. elliptica in some areas of the middle estuary evidence discharges of lower-salinity water from a nearby fish farm. Ostracods from the marine shelf reach the inner estuary, but continental species are not provided by the rivers. The low river influence may be due to Nansa River flow regulation upstream, which hampers the transport of fluvial sediments, resulting in an increase in sand in the mudflat and low marshes, the latter fact confirmed by the numbers of L. castanea and L. porcellanea, much higher than in other estuaries in the southern Bay of Biscay.

  6. North Inlet-Winyah Bay National Estuarine Research Reserve's (NERR) Estuarine Water Quality Data for the North Inlet and Winyah Bay Estuaries, Georgetown, South Carolina: 1993-2002

    Baruch Institute for Marine and Coastal Sciences, Univ of South Carolina — The North Inlet Estuary and the adjacent lower northeastern section of the Winyah Bay Estuary were designated as part of the National Estuarine Research Reserve...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-05-15

    In 2002 with support from the U.S. Army Corps of Engineers (USACE), an interagency research team began investigating salmon life histories and habitat use in the lower Columbia River estuary to fill significant data gaps about the estuary's potential role in salmon decline and recovery . The Bonneville Power Administration (BPA) provided additional funding in 2004 to reconstruct historical changes in estuarine habitat opportunities and food web linkages of Columbia River salmon (Onchorhynchus spp.). Together these studies constitute the estuary's first comprehensive investigation of shallow-water habitats, including selected emergent, forested, and scrub-shrub wetlands. Among other findings, this research documented the importance of wetlands as nursery areas for juvenile salmon; quantified historical changes in the amounts and distributions of diverse habitat types in the lower estuary; documented estuarine residence times, ranging from weeks to months for many juvenile Chinook salmon (O. tshawytscha); and provided new evidence that contemporary salmonid food webs are supported disproportionately by wetland-derived prey resources. The results of these lower-estuary investigations also raised many new questions about habitat functions, historical habitat distributions, and salmon life histories in other areas of the Columbia River estuary that have not been adequately investigated. For example, quantitative estimates of historical habitat changes are available only for the lower 75 km of the estuary, although tidal influence extends 217 km upriver to Bonneville Dam. Because the otolith techniques used to reconstruct salmon life histories rely on detection of a chemical signature (strontium) for salt water, the estuarine residency information we have collected to date applies only to the lower 30 or 35 km of the estuary, where fish first encounter ocean water. We lack information about salmon habitat use, life histories, and growth within the long tidal-fresh reaches of the main-stem river and many tidally-influenced estuary tributaries. Finally, our surveys to date characterize wetland habitats within island complexes distributed in the main channel of the lower estuary. Yet some of the most significant wetland losses have occurred along the estuary's periphery, including shoreline areas and tributary junctions. These habitats may or may not function similarly as the island complexes that we have surveyed to date. In 2007 we initiated a second phase of the BPA estuary study (Phase II) to address specific uncertainties about salmon in tidal-fresh and tributary habitats of the Columbia River estuary. This report summarizes 2007 and 2008 Phase II results and addresses three principal research questions: (1) What was the historic distribution of estuarine and floodplain habitats from Astoria to Bonneville Dam? (2) Do individual patterns of estuarine residency and growth of juvenile Chinook salmon vary among wetland habitat types along the estuarine tidal gradient? (3) Are salmon rearing opportunities and life histories in the restoring wetland landscape of lower Grays River similar to those documented for island complexes of the main-stem estuary? Phase II extended our analysis of historical habitat distribution in the estuary above Rkm 75 to near Bonneville Dam. For this analysis we digitized the original nineteenth-century topographic (T-sheets) and hydrographic (H-sheets) survey maps for the entire estuary. Although all T-sheets (Rkm 0 to Rkm 206) were converted to GIS in 2005 with support for the USACE estuary project, final reconstruction of historical habitats throughout the estuary requires completion of the remaining H-sheet GIS maps above Rkm 75 and their integration with the T-sheets. This report summarizes progress to date on compiling the upper estuary H-sheets above Rkm 75. For the USACE estuary project, we analyzed otoliths from Chinook salmon collected near the estuary mouth in 2003-05 to estimate variability in estuary residence times among juvenile out migrants. In Phase II we expanded these a

  8. Gravity and magnetic data of Midway Valley, southwest Nevada

    International Nuclear Information System (INIS)

    Detailed gravity and ground magnetic data collected along five traverses across Midway Valley on the eastern flank of Yucca Mountain in southwest Nevada are described. These data were collected as part of an effort to evaluate faulting in the vicinity of proposed surface facilities for a potential nuclear waste repository at Yucca Mountain. Geophysical data show that Midway Valley is bounded by large gravity and magnetic anomalies associated with the Bow Ridge and Paintbrush Canyon faults, on the west side of Exile Hill and on the west flank of Fran Ridge, respectively. In addition, Midway Valley itself is characterized by a number of small-amplitude anomalies that probably reflect small-scale faulting beneath Midway Valley

  9. Gravity and magnetic study of Yucca Wash, southwest Nevada

    International Nuclear Information System (INIS)

    Gravity and ground magnetic data were collected along five traverses across and one traverse along Yucca Wash in the southwest quadrant of the Nevada Test Site. Two additional ground magnetic profiles were collected approximately 100 m to either side of the longitudinal profile. These data do not indicate major vertical offsets greater than 100 m using a density contrast of 0.2 to 0.3 g/cm3 along the proposed Yucca Wash fault. A broad magnetic high coincides with the location of the hydrologic gradient. Density profiling, a technique used to determine the average density of small topographic features, suggests that the density of near-surface material in the vicinity of Yucca Wash is about 2.0 g/cm3

  10. Present condition of uranium exploration and the prospecting direction in southwest China

    International Nuclear Information System (INIS)

    Southwest China is one of the important areas where uranium is distributed. After exploration and research of 50 years, the metallogenic conditions for uranium deposits in Southwest China have been studied more deeply. It is found that uranium ore in Southwest China has more complete types, less deposits and more mineral occurrences, and the amount of uranium resources is disproportionate to the area of Southwest China. Researches of years show that Southwest China is characterized by thick crust. thick sedimentary cover, weak crust-mantle interaction, weak deep flu id activity in shallow strata, strong dynamic formation in shallow strata and obvious deep geologic process on block mar- gins. In this paper, the control of deep geologic process and evolution in uranium metallogenesis in Southwest China is studied by employing new theories and thoughts on the fundamental concept that deep geologic process and evolution has important control on super-large scale deposits. The study focuses on the crust-mantle structure and evolution with uranium metallogenesis, structural and magmatic activity and deep fluid activity with uranium metallogenesis, and ore-con- trolling role of penetrating faults on block edges and inside the blocks. To offer theoretic basis for large-scale uranium deposit prospecting in Southwest China, the key research on uranium deposit in Southwest China in future should be on the deep geologic evolution and uranium metallogenesis in Western Qinling Region, the uranium metallogenesis of iron oxide copper gold deposits on Kangdian axis, the uranium metallogenesis in Yunnan-Guizhou contiguous area, the hydrothermal uranium metallogenesis in Eastern Tibet and Western Sichuan, and the connection between sandstone type uranium deposit and magmatic activity. Meanwhile, the above regions are also the key ones for uranium deposit prospecting in Southwest China in a rather long period in future. (authors)

  11. The response of microalgal biomass and community composition to environmental factors in the Sundays Estuary

    Scientific Electronic Library Online (English)

    Daisy, Kotsedi; Janine B, Adams; Gavin C, Snow.

    Full Text Available The Sundays Estuary is permanently open to the sea and experiences regular freshwater inflow in the form of agricultural return flows with large supplies of nutrients. The objectives of this study were to measure microalgal biomass and community composition and relate these to freshwater inflow, wat [...] er quality and other environmental variables. These data can then be used in setting the ecological water requirements of the estuary. Surveys in August 2006, March 2007, February, June and August 2008 showed that salinity less than 10, expressed in practical salinity units, mostly occurred from 12.5 km from the mouth in the middle reaches of the estuary, which was also where the highest water column chlorophyll a (>20 ?g.?-1) was found. The study showed that different groups of microalgae formed phytoplankton blooms during individual sampling sessions. These included blooms of green algae (August 2006), flagellates (March 2007), dinoflagellates (June 2008) and diatom species (February and August 2008). The estuary was then sampled over 5 consecutive weeks from March to April 2009 to identify environmental factors that support different microalgal bloom species. Phytoplankton blooms were found during Weeks 1, 4 and 5 from the middle to the upper reaches of the estuary. It was shown that diatoms occurred in blooms during warm, calm conditions whereas wind-mixing and reduced temperature, as a result of a cold front during 17 to 19 March 2009, promoted the dominance of flagellates throughout the estuary although they were present at all times. Dominant diatom species (Cylindrotheca closterium, Cyclotella atomus and Cyclostephanus dubius) indicated brackish, nutrient-rich water. Nanoplankton (2.7 - 20 ?m) was dominant during each week sampled and contributed 55 - 79% to the phytoplankton biomass. Maximum benthic chlorophyll a was found 12.5 km from the mouth. This study is the first to show successive chlorophyll a blooms consisting of different phytoplankton groups in an estuary, an indication of the eutrophic state of the system.

  12. Variability of macrobenthic assemblages under abnormal climatic conditions in a small scale tropical estuary

    Science.gov (United States)

    Lucero R., Carlos H.; Cantera K., Jaime R.; Romero, Isabel C.

    2006-06-01

    Macrobenthic assemblages associated with mangrove mud flats were studied at three stations in the Dagua River Estuary (Colombian coast, Tropical Eastern Pacific) to assess broad distribution patterns with relation to hydrographical and sediment conditions during the cold (La Niña) phase of the 1997-2000 El Niño/Niña Phenomenon (ENSO Niño/Niña). During the study period, abnormal water and interstitial temperature, high dissolved oxygen and low salinity conditions were present in the water column of the small scale (5.5 km long) estuary, reducing its extension and moving estuarine conditions downstream. Sediment samples were collected for sediment analysis (grain size, water content) and biological studies (specific composition, relative abundance, diversity, evenness and trophic structure) from quadrates (25 × 25 cm) located in the lower, middle and upper regions of the estuary. Macrobenthic assemblages at the upper estuary were composed of 78 species and dominated by Tanaidaceans, suggesting the direct effect of freshwater inflow, and by some polychaetes in the lower region, showing marine influence. Diversity and evenness increased along the salinity gradient from the upper region of the estuary towards the lower region. Surface deposit feeders (SDF, 72.2%) and sub-surface deposit feeders (SSDF, 21%) were dominant as trophic groups. SDF were the most abundant group in the upper estuary, SSDF dominated the lower estuary. These patterns were controlled by the abnormal conditions generated by the cold phase of ENSO (Niño/Niña) in water temperature, higher deposition of organic matter and low salinity that changed the estuarine's typical macrobenthic assemblage structure, with dominance of marine species to one characterized by few abundant freshwater species (Tanaidaceans, insects).

  13. Seasonal dynamics and conservative mixing of dissolved organic matter in the temperate eutrophic estuary Horsens Fjord

    DEFF Research Database (Denmark)

    Markager, Stiig; Stedmon, Colin

    2011-01-01

    This study presents the results of a year-long study investigating the characteristics of dissolved organic matter (DOM) in the Danish estuary, Horsens Fjord. The estuary is shallow with a mean depth of 2.9 m and receives high loadings of inorganic nutrients from its catchment. The behaviour of different DOM parameters i.e. dissolved organic carbon (DOC), nitrogen (DON), and phosphorous (DOP), light absorption and eight fluorescence components, were analysed relative to conservative mixing. Many of the parameters did not behave conservatively. For DON, DOP and absorption, more than 65% of the freshwater concentration was removed initially at salinities below 12. At higher salinities two general patterns were identified. Concentrations of DON, DOP and four humic fluorescent fractions were not, or only weakly, related to salinity, showing that other processes than mixing were involved. Other parameters such as DOC and two terrestrial humic components behaved conservatively. The same was true for DON during winter. These results are consistent with the finding that autochthonous DOM was the dominant source of DOM in this estuary. The molar C:N and C:P ratios for DOM (DOC:DON and DOC:DOP) in freshwater were 11 and 758, respectively. The DOC:DON ratio increased in the estuary during the productive season to average values between 13 and 17, due to accumulation of DOC and removal of DON. The DOC:DOP ratio decreased within the estuary showing that in general DOM was enriched with phosphorous, however, during the spring, when phosphorous was limiting, the DOC:DOP ratio increased due to low DOP concentrations. We hypothesise that in estuaries with high loadings of inorganic nutrients relative to DOM, production and degradation of DOM within the estuary will dominate over allochthonous inputs and control both concentration and characteristics of DOM. A conceptual model for this hypothesis is presented. (C) 2011 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

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

    2003-01-01

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

  15. Decay of eddies at the South-West Indian Ridge

    Scientific Electronic Library Online (English)

    Jonathan V., Durgadoo; Isabelle J., Ansorge; Beverly A., de Cuevas; Johann R.E., Lutjeharms; Andrew C., Coward.

    Full Text Available The South-West Indian Ridge in the Indian sector of the Southern Ocean is a region recognised for the creation of particularly intense eddy disturbances in the mean flow of the Antarctic Circumpolar Current. Eddies formed at this ridge have been extensively studied over the past decade using hydrogr [...] aphic, satellite, drifter and float data and it is hypothesised that they could provide a vehicle for localised meridional heat and salt exchange. The effectiveness of this process is dependent on the rate of decay of the eddies. However, in order to investigate eddy decay, logistically difficult hydrographic monitoring is required. This study presents the decay of cold eddies at the South-West Indian Ridge, using outputs from a high-resolution ocean model. The model's representation of the dynamic nature of this region is fully characteristic of observations. On average, 3-4 intense and well-defined cold eddies are generated per year; these eddies have mean longevities of 5.0±2.2 months with average advection speeds of 5±2 km/day. Most simulated eddies reach their peak intensity within 1.5-2.5 months after genesis and have depths of 2000 m - 3000 m. Thereafter they dissipate within approximately 3 months. The decay of eddies is generally characterised by a decrease in their sea surface height signature, a weakening in their rotation rates and a modification in their temperature-salinity characteristics. Subantarctic top predators are suspected to forage preferentially along the edges of eddies. The process of eddy dissipation may thus influence their feeding behaviour.

  16. Resumption of intercourse after childbirth in southwest Nigeria.

    Science.gov (United States)

    Adanikin, Abiodun I; Awoleke, Jacob O; Adeyiolu, Adewale; Alao, Omolola; Adanikin, Pipeloluwa O

    2015-08-01

    Objective To determine the history of resumption of intercourse after childbirth and associated contraceptive practices among women in the southwest region of Nigeria. Methods A cohort of 181 women with live births was followed up for 6 months after delivery. Enquiry about the time of first intercourse after childbirth, associated dyspareunia, use of contraception, etc was made during the postnatal clinic visits and/or by telephone contact. Results Fifty (27.6%) had coitus within six weeks of childbirth, it increased to 115 (63.3%) at three months and 127 (70.2%) by six months post-delivery. Prevalence of dyspareunia was 36.2%. Eighty three (65.4%) of sexually active women practiced contraception which was predominantly use of male condom and withdrawal method. Co-habitation with husband (adjusted OR: 6.30; 95% CI: 2.56-17.01; p = 0.001) and mode of delivery (adjusted OR: 2.45; 95% CI: 1.30-4.73; p = 0.006) were strong predictors of commencement of sexual intercourse within six months postpartum. Significantly fewer women who had Caesarean section resumed coitus within six months when compared with those who had vaginal deliveries (59.2% versus 78.4%). Perineal injury did not predict resumption of coitus or experience of dyspareunia. Conclusion In contrast to the norm, more women in southwest Nigeria are resuming coitus soon after childbirth. It is imperative to scale up counselling on postpartum sexuality and contraception within the maternal health services in this region. PMID:25372022

  17. Modeling local paleoclimates and validation in the southwest United States

    International Nuclear Information System (INIS)

    In order to evaluate the spatial and seasonal variations of paleoclimate in the southwest US, a local climate model (LCM) is developed that computes modern and 18,000 yr B.P. (18 ka) monthly temperature and precipitation from a set of independent variables. Independent variables include: terrain elevation, insolation, CO2 concentration, January and July winds, and January and July sea-surface temperatures. Solutions are the product of a canonical regression function which is calibrated using climate data from 641 stations from AZ, CA, CO, NM, NV, UT in the National Weather Service Cooperative observer network. Validation of the LCH, using climate data at 98 climate stations from the period 1980--1984, indicates no significant departures of LCM solutions from climate data. LCM solutions of modern and 18 ka climate are computed at a 15 km spacing over a rectangular domain extending 810 km east, 360 km west, 225 km north and 330 km south of the approximate location of Yucca Mt., KV. Solutions indicate mean annual temperature was 5 degrees C cooler at 18 ka and mean annual precipitation increased 68%. The annual cycle of temperature and precipitation at 18 ka was amplified with summers about 1 degrees C cooler and 71% drier, and winters about 11 degrees C colder and 35% wetter than the modern. Model results compare quite reasonably with proxy paleoclimate estimates from glacial deposits, pluvial lake deposits, pollen records, ostracodes records and packrat maddcords, ostracodes records and packrat madden records from the southwest US However, bias (+5 degrees C to +10 degrees C) is indicated for LCM solutions of summer temperatures at 18 ka

  18. A lightning climatology of the South-West Indian Ocean

    Directory of Open Access Journals (Sweden)

    C. Bovalo

    2012-08-01

    Full Text Available The World Wide Lightning Location Network (WWLLN data have been used to perform a lightning climatology in the South-West Indian Ocean (SWIO region from 2005 to 2011. Maxima of lightning activity were found in the Maritime Continent and southwest of Sri Lanka (>50 fl km?2 yr?1 but also over Madagascar and above the Great Lakes of East Africa (>10–20 fl km?2 yr?1. Lightning flashes within tropical storms and tropical cyclones represent 50 % to 100 % of the total lightning activity in some oceanic areas of the SWIO (between 10° S and 20° S.

    The SWIO is characterized by a wet season (November to April and a dry season (May to October. As one could expect, lightning activity is more intense during the wet season as the Inter Tropical Convergence Zone (ITCZ is present over all the basin. Flash density is higher over land in November–December–January with values reaching 3–4 fl km?2 yr?1 over Madagascar. During the dry season, lightning activity is quite rare between 10° S and 25° S. The Mascarene anticyclone has more influence on the SWIO resulting in shallower convection. Lightning activity is concentrated over ocean, east of South Africa and Madagascar.

    A statistical analysis has shown that El Niño–Southern Oscillation mainly modulates the lightning activity up to 56.8% in the SWIO. The Indian Ocean Dipole has a significant contribution since ~49% of the variability is explained by this forcing in some regions. The Madden–Julian Oscillation did not show significative impact on the lightning activity in our study.

  19. A comparison of selected ecosystem attributes of three South African estuaries with different freshwater inflow regimes, using network analysis

    Science.gov (United States)

    Scharler, Ursula M.; Baird, Dan

    2005-06-01

    Carbon flow networks of the Kromme, Swartkops and Sundays estuaries, situated on the south coast of South Africa, were analysed using ecological network analysis. A major difference between the three estuaries is the freshwater inflow regimes: The Kromme Estuary receives very little freshwater (annual mean 0.07 m -3 s -1), the Swartkops Estuary receives annually about 0.82 m -3 s -1 while the Sundays Estuary receives on average about 2.74 m -3 s -1 annually. Ecological network analysis revealed differences between most ecosystem attributes such as the cycling of carbon, trophic structure, the organisational and developmental status in terms of ascendency and redundancy, and regarding the contribution to and dependencies of compartments to and on one another in the network. Due to the lack of frequent freshwater inflow and consequently the renewal of the nutrient pool, the Kromme Estuary recycles most of its material and showed the highest detritivory/herbivory ratio (57:1), whereas the Sundays recycles the least proportion and had the lowest detritivory/herbivory ratio at 10:1. The Sundays Estuary, hitherto believed to be dominated by pelagic production, was found to rely more on the benthic biota in terms of carbon throughput as inferred from the contribution and dependency coefficients, than on pelagic communities. Due to the low rate of fresh water inflow into the Kromme Estuary, the absence of an axial salinity gradient, a comparatively high Finn Cycling Index of 40%, and the long water exchange time, this system appears to have developed into an "arm" of the sea. System level properties such as the A/ C ratio, the Average Mutual Information index, and the food web connectance index, increase from the lowest values calculated for the Kromme Estuary, intermediate for the Swartkops Estuary, and highest for the Sundays Estuary, while the FCI followed an inverse trend between the three systems.

  20. CO2 supersaturation and net heterotrophy in a tropical estuary (Cochin, India): Influence of anthropogenic effect - Carbon dynamics in tropical estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Gupta, G.V.M.; Thottathil, S.D.; Balachandran, K.K.; Madhu, N.V.; Madeswaran, P.; Nair, S.

    2009-01-01

    . Modelling of tidal hydrodynamics for a tropical ecosystem with implications for pollutant dispersion (Cochin Estuary, South India). Ocean Dynamics 58: 76-88 DOI:10.1007/s10236-008-0153-6. Biddanda BA, Cotner JB. 2002. Love handles in aquatic ecosystems...

  1. Concerns in assessing radiological releases to a major estuary

    International Nuclear Information System (INIS)

    Full text: In the State of Virginia, the James River flows into the Chesapeake Bay and from the mouth of the James River to the fall line the river is under the influence of tidal forces. There are several centers of commerce along the river including an international port of call at the mouth of the James. Associated with the centers of commerce are potential sources of radioactive materials for being released to the river. Two hundred miles inland, the Babcock and Wilcox nuclear fuels processing plants are situated along-side the James River, which has been known to flood its banks quickly in the mountainous regions of Virginia. Storage tanks have been swept downstream from this facility in a previous flood. Fortunately, the tanks were not destroyed. Another source of a possible release is the Suny Nuclear Power Station located on the James River about fifty miles from the Chesapeake Bay. In the cities of Norfolk and Newport News, shipyards are fueling and defueling the Navy's nuclear powered fleet. In addition, many of the Navy's ships are carrying nuclear weapons. These activities may also result in an inadvertent release. In assessing the radiological release from any one of the previously mentioned activities, it is obvious that dilution of the material released into the river is a major factor in dose assessment, as well as the fact that the water is brackish and not suitable as a source of potable water. However, dilution in this case may not be the simple solution. We also have to remember that this estuary is under tidal effects, which means that the materials may not be going out to sea to be further diluted as quickly as we would like to think. It may be possible that the material will be carried up river as far as the fall line and deposited, or deposited along the river's banks. From Virginia's experience with the pesticide, Kepone, materials may be deposited along the estuary and enter the food chain thereby necessitating the limitation of taking shellfish and commercial, recreational fishing. A major problem in assessing the environmental impact is determining what isotopes and in what forms will be taken up in species of commercial interest or those species that would otherwise contribute to man's exposure. Even though water to the lower James River is brackish, there may be uses for the water that have not been considered before, such as use by desalinization plants. Currently, the City of Virginia Beach has difficulty maintaining an adequate supply of water and there has been some discussion of building desalinization plants. If such a plant were in operation, the health physicist would have to consider the consequences of the material being concentrated and the problems associated with disposal of resins or contamination of the equipment. Most ships distill water while at sea and probably the still would not be operating while in port; however, the brackish water is used for fire fighting and many prove to be a source of contamination on the piers, unless an advisory was issued. At the mouth of the James River is located a major beach resort and in the event of a major release its business would suffer if the radiological conditions were not assessed and communicated effectively to the public promptly. I would like to conclude this discussion by stating that citizens in states surrounding the Chesapeake Bay have become very sensitive to the environment of the Bay and that they no longer tolerate rivers being used as sewers. As health physicists we also need to be sensitive to these issues and be mindful that estuaries are more complicated than a direct sewer drain to the ocean for wastes even though the discharges may be accidental. (author)

  2. The "Southwest Effect" Revisited: An Empirical Analysis of the Effects of Southwest Airlines and JetBlue Airways on Incumbent Airlines from 1993 to 2009

    Directory of Open Access Journals (Sweden)

    Steven M. Wu

    2012-09-01

    Full Text Available The expansion of Southwest Airlines and JetBlue Airways has sparked new empirical interest in the effects of low-cost carriers (LCC on existing airfares. Namely, empirical studies have attempted to capture the threat, or potential competition, of an entrant. This paper examines incumbent airline prices as a result of potential and actual competition from both Southwest Airlines and JetBlue Airways from 1993 to 2009 by analyzing mean airfares as well as price dispersion on incumbent routes. I incorporate a panel OLS with fixed effects model as well as GLS model with random effects. Consistent with re-cent literature, this paper finds that legacy incumbents cut fares significantly when threatened by Southwest Airlines. However, low-cost incumbents do not exhibit the same magnitude of pre-emptive price cutting. When threatened by JetBlue, neither legacy nor low-cost carriers cut fares significantly, suggest-ing that incumbents react differently when threatened by Southwest versus JetBlue. The evidence of increased price dispersion is mixed with price dis-persion decreasing on legacy carrier routes as a result of Southwest threat and entry but increasing on legacy carrier routes as a result of JetBlue threat and entry.

  3. Bacterial Communities in Kuantan Estuary of Pahang Malaysia

    Directory of Open Access Journals (Sweden)

    K.C.A. Jalal

    2010-01-01

    Full Text Available Physicochemical parameters influence the vertical spatial distribution of microbial communities in any water bodies. Based on this perspective, a study on physicochemical parameters and bacterial community was carried out from five stations on January-June 2009 at the Kuantan estuary of Pahang, Malaysia. The temperature was ranged from 25.01-27.48°C, salinity fluctuation observed 0.03-25.84 ppt, Dissolved Oxygen (DO 6.10 to 10.73 mg L-1, specific conductivity ranged from 0.10 to 42.43 mS cm-1, Total Dissolved Solids (TDS ranged from 0.05 to 26.36 g L-1 and pH varied from 5.69 to 8.11 and chlorophyll a ranged 0.01 to 1.14 ?g L-1. The nitrite concentration was higher at St. 5 (0.19 mg L-1 followed by St. 4 (0.16 mg L-1 and it was lowest at St. 1 (0.13 mg L-1. Similarly, high phosphorus content (0.17 mg L-1 was found at St. 4 followed by St. 5 (0.16 mg L-1 while, it was lowest at St. 1 (0.08 mg L-1. Out of 19 isolated bacteria most dominant bacteria were Citrobacter freundii followed by Leuconostoc sp. and Staphylococcus xylosus. High bacterial colony (cfu mL-1 was observed at St. 4 (570 cfu mL-1 in water column followed by St. 5 (490 cfu mL-1. In contrary, it was lowest at St. 2 (213 cfu mL-1. Meanwhile, the highest bacterial colony in sediment was observed at St. 4 (390 cfu mL-1 followed by St. 5 (333 cfu mL-1. It was lowest observed at St. 2 (167 cfu mL-1. Nevertheless, a continuous monitoring of water quality is needed in this estuary especially at St. 4 and 5 which could be alarming in the long run due to deposition of nutrients from the outlets of fishing villages and industry sources.

  4. Fishes and fisheries in tropical estuaries: The last 10 years

    Science.gov (United States)

    Blaber, S. J. M.

    2013-12-01

    Since 2002 there has been an increase in knowledge of many aspects of the biology and ecology of tropical estuarine fishes, as well as significant changes to many estuarine fisheries. Analyses of literature databases (2002-2012) show that: of the c. 600 relevant papers, 52% are primarily related to ecology, 11% to conservation, 11% to anthropogenic and pollution effects on fishes, 9% to fisheries, 7% to aquaculture, 4% to study techniques, and 1% each to fish larvae, effects of fishing, taxonomy, climate change, evolution and genetics. In terms of geographic spread 17% are from North America, 15% from south Asia, 14% from the Caribbean, 13% from Australasia, 12% from Africa and 9% each from South America and SE Asia. Research papers came from 50 countries of which the dominant were USA (15%), India (12%), Australia (11%) and Brazil (7%). Increasing numbers of studies in West Africa, SE and South Asia and South America have increased basic knowledge of the ecology of estuarine fish faunas. Increases in understanding relate to: roles of salinity, turbidity and habitat diversity; connectivity between habitats; water flow; ecological drivers of spatial variability; scale dependent variation; thermal tolerances; movement patterns; food webs; larval adaptations; and the viability of areas heavily impacted by human activities. New reviews both challenge and support different aspects of the estuarine dependence paradigm - still perhaps one of the main research issues - and the protective function of estuaries and mangroves for juvenile fishes has received attention in relation to e.g. predation risks and fisheries. There have also been significant advances in the use of guilds and biodiversity models. Fishing pressures have continued unabated in most tropical estuaries and are summarised and management issues discussed. Understanding of the relationships between fisheries production and mangroves has advanced and significant differences have emerged between Indo-West Pacific and Atlantic systems. The effects of fishing itself have also received attention and research is often related to conservation studies. The effects of anthropogenic activities are reviewed and important advances in mitigation are discussed. Restoration of estuarine habitats, such as mangroves, previously taking place mainly in countries such as Australia and USA, is now occurring in more countries. The design of reserves and the use of protected areas as management tools are gaining credence. Finally, the evidence for actual and potential effects of climate change is discussed.

  5. Size, distribution and sediment biodeposition of prolific bivalves in small estuaries

    Science.gov (United States)

    Callaway, Ruth; Grenfell, Suzanne; Bertelli, Chiara; Mendzil, Anouska; Moore, Jon

    2014-10-01

    The growth and distribution of bivalves in estuaries is generally driven by access to food, hydrodynamic forces and sedimentary conditions that facilitate recruitment and allow persistent settlement. Factors such as site elevation or sediment properties have a significant impact, but there are few studies quantifying the relative importance of different factors in an entire estuary. We carried out an estuary-wide survey of the cockle Cerastoderma edule L. by sampling 343 sites in a small estuary, the Burry Inlet in South Wales, UK. We determined the extent to which site elevation, as an indicator for the duration of feeding, sediment properties and position inside the estuary, explained variation in the size and density of the bivalve. We also analysed the production of faeces and pseudo-faeces per cockle. The population consisted almost entirely of 1-year old cockles, the average size was 14.7 ± 2.7 mm and the average density was 56 ± 189 cockles 0.1 m-2 (mean ± SD). Altogether 37% of the variation in size was explained by two factors: elevation of site (15%) and amount of clay & silt in sediments (22%). Variation in density appeared to play no significant role in determining size. Density was significantly linked to sediment properties (32%) and position inside the estuary (4%). Sediment biodeposition, the amount of material discharged per cockle, was 0.032 ± 0.017 g dry weight, the whole population thereby producing an estimated 387 tonnes of faeces and pseudo-faeces in the entire estuary per day. The study confirmed that access to food is a principal driver of growth, but the relatively small proportion of the variation in size explained by site elevation highlights that other factors play an important role. Sediment characteristics in particular were of importance to variation in size as well as density. It seems plausible that sediment properties were a proxy for factors such as bedload movement and exposure, which are more likely causal factors for distribution patterns. However, the bivalves may also actively favour certain sediment compositions for ease of burrowing and food availability. We suggest that the role of active and passive movement of bivalves within an estuary needs further clarification, which would affect individual growth rates and spatial size distribution patterns. The considerable amount of mucus bound material discharged by cockles suggests that the contribution of prolific bivalves to habitat properties of small estuaries is under-estimated.

  6. Open water processes of the San Francisco Estuary: From physical forcing to biological responses

    Directory of Open Access Journals (Sweden)

    Wim Kimmerer

    2004-02-01

    Full Text Available This paper reviews the current state of knowledge of the open waters of the San Francisco Estuary. This estuary is well known for the extent to which it has been altered through loss of wetlands, changes in hydrography, and the introduction of chemical and biological contaminants. It is also one of the most studied estuaries in the world, with much of the recent research effort aimed at supporting restoration efforts. In this review I emphasize the conceptual foundations for our current understanding of estuarine dynamics, particularly those aspects relevant to restoration. Several themes run throughout this paper. First is the critical role physical dynamics play in setting the stage for chemical and biological responses. Physical forcing by the tides and by variation in freshwater input combine to control the movement of the salinity field, and to establish stratification, mixing, and dilution patterns throughout the estuary. Many aspects of estuarine dynamics respond to interannual variation in freshwater flow; in particular, abundance of several estuarine-dependent species of fish and shrimp varies positively with flow, although the mechanisms behind these relationships are largely unknown. The second theme is the importance of time scales in determining the degree of interaction between dynamic processes. Physical effects tend to dominate when they operate at shorter time scales than biological processes; when the two time scales are similar, important interactions can arise between physical and biological variability. These interactions can be seen, for example, in the response of phytoplankton blooms, with characteristic time scales of days, to stratification events occurring during neap tides. The third theme is the key role of introduced species in all estuarine habitats; particularly noteworthy are introduced waterweeds and fishes in the tidal freshwater reaches of the estuary, and introduced clams there and in brackish water. The final theme is the rather heterogeneous set of results from monitoring and research in the estuary. For example, some topics have been subjects of intense activity both in research and monitoring (e.g., physical dynamics of the upper estuary, phytoplankton blooms, while others have received little attention (e.g., microzooplankton. In addition, both research and monitoring have emphasized some regions of the estuary (e.g., the Sacramento-San Joaquin Delta over others (e.g., San Pablo Bay. In addition, ecological modeling and synthesis has emphasized lower trophic levels over higher. Opportunities for restoration in the open waters of the estuary are somewhat limited by the lack of scientific basis for restoration, and the difficulty in detecting ecosystem responses in the context of high natural variability.

  7. A theoretical framework for analyzing the effect of external change on tidal dynamics in estuaries

    Science.gov (United States)

    CAI, H.; Savenije, H.; Toffolon, M.

    2013-12-01

    The most densely populated areas of the world are usually located in coastal areas near estuaries. As a result, estuaries are often subject to intense human interventions, such as dredging for navigation, dam construction and fresh water withdrawal etc., which in some areas has led to serious deterioration of invaluable ecosystems. Hence it is important to understand the influence of such interventions on tidal dynamics in these areas. In this study, we present one consistent theoretical framework for tidal hydrodynamics, which can be used as a rapid assessment technique that assist policy maker and managers to make considered decisions for the protection and management of estuarine environment when assessing the effect of human interventions in estuaries. Analytical solutions to the one-dimensional St. Venant equations for the tidal hydrodynamics in convergent unbounded estuaries with negligible river discharge can be cast in the form of a set of four implicit dimensionless equations for phase lag, velocity amplitude, damping, and wave celerity, as a function of two localized parameters describing friction and convergence. This method allows for the comparison of the different analytical approaches by rewriting the different solutions in the same format. In this study, classical and more recent formulations are compared, showing the differences and similarities associated to their specific simplifications. The envelope method, which is based on the consideration of the dynamics at high water and low water, can be used to derive damping equations that use different friction approximations. This results in as many analytical solutions, and thereby allows one to build a consistent theoretical framework. Analysis of the asymptotic behaviour of the equations shows that an equilibrium tidal amplitude exits reflecting the balance between friction and channel convergence. The framework is subsequently extended to take into account the effect of river discharge. Hence, the analytical solutions are applicable even in the upstream part of an estuary, where the influence of river discharge is remarkable. The proposed analytical solutions are transparent and practical, allowing a quantitative and qualitative assessment of human interventions (e.g., dredging, flow reduction) on tidal dynamics. Moreover, they are rapid assessment techniques that enable the users to set up a simple model and to understand the functioning of the system with a minimum of information required. The analytical model is illustrated in three large-scale estuaries with significant influence by human activities, i.e., the Scheldt estuary in the Netherlands, the Modaomen and the Yangtze estuaries in China. In these estuaries, the correspondence with observations is good, which suggests that the proposed model is a useful, yet realistic and reliable instrument for quick detection of the effect of human interventions on tidal dynamics and subsequent environmental issues, such as salt intrusion.

  8. Fish and macro-crustacean communities and their dynamics in the Severn Estuary.

    Science.gov (United States)

    Henderson, P A; Bird, D J

    2010-01-01

    The species of fish and macro-crustacean living within the Severn Estuary are reviewed. The fish community is notably species rich and exceeds 100 species in total for the estuary. Standardised long-term sampling at Hinkley Point in Bridgwater Bay gives a total complement of 83 for a single locality and this number is increasing by about one new species every two years. Most of these new species are moving in from centres of population lying to the south of the estuary. Almost all species of fish and macro-crustacean living within the estuary undertake regular migrations so that they tend to move seasonally in waves up and down the estuary. For fish, both species richness and the total abundance reach a maximum in late summer and autumn. The timing of this peak varies between the upper and lower estuary. This seasonal maximum is primarily caused by the arrival of the new recruits which use the estuary as a nursery. In contrast, crustaceans tend to be at their most diverse and abundant in early to mid summer. Using a 30-year time series of fish and crustacean abundance collected at Hinkley Point it is shown that major changes in the structure of the community are now underway and there are considerable recent changes in the abundance. However, some abundant species, including sand goby, Pomatoschistus spp., whiting, Merlangius merlangus and sprat, Sprattus sprattus, the three most abundant species in the estuary, have shown no long-term trend. At present, approximately 20% of the fish and macro-crustaceans observed in Bridgwater Bay are undergoing rapid, typically exponential, change in abundance. For a numerically abundant, diverse, fauna composed of approximately 90 species such levels of change are unexpected and suggest that the system is presently far from equilibrium. In some cases, the observed changes can be related to recent warming and the North Atlantic Oscillation. The overall increase in fish abundance observed may reflect a general improvement in water quality and a reduction in other anthropogenic impacts such as mortality in cooling-water intakes. The potential impacts of tidal power generation in the Severn Estuary are reviewed. There is considerable potential for any major installation to impact the fish and crustacean populations as they migrate and also alter the nature of the habitat resulting in changes in community composition. A particular difficulty in predicting the future impact of harnessing tidal energy is that the present community is already changing rapidly. The ability of fish and crustaceans to pass through the turbines unharmed will be a key issue in an assessment of the impact of tidal power generation. PMID:20074757

  9. Mangroves and Associated Flora of Vashista and Vainateyam Estuaries, A.P. India

    Directory of Open Access Journals (Sweden)

    Geddada Mohan NARASIMHA RAO

    2010-12-01

    Full Text Available Mangroves are highly productive ecosystems occurs intertidal regions only. Mangroves and associated flora occurring in two major estuaries of Godavari river (India were studied using transect with 4x4 m2 quadrats and the quadrat samples were analyzed. Seasonal data were collected on environmental, hydrographical and chemical observations from three different stations of the two estuaries. Low values in Secchi depth, salinity and pH were reported during the monsoon season, while higher values were reported in pre-monsoon and post monsoon seasons. In the present study three mangrove species and nine associated species were reported. Transect studies in these two estuaries showed that mangrove and halophytes occurred up to 40 meters from water front region. In some places mangrove vegetation was in the form of long strips only. In Vainateyam estuary, the species with the highest density was Suaeda monoica whereas the species with lowest density was Avicennia officinalis. In Vashista estuary, maximum density was reported for Suaeda maritima and minimum density for Avicennia officinalis. The maximum height in these two stations varied from 5 to 8 meters only. Percentage frequencies of DBH (Density at Breast Height classes were estimated. In the present study only two diameter classes were reported. This is indicative of the small and bushy mangrove vegetation in the region studied. Human interference, urban settlements and aqua industry play a critical impact on the survival of these tropical ecosystems. If management and conservation programmes are not undertaken, these ecosystems may be depleted.

  10. Abundance and Diversity of Mould Inhabiting Muara Layang Estuary Sediment, Bangka Belitung Islands

    Directory of Open Access Journals (Sweden)

    MUHAMMAD ILYAS

    2009-04-01

    Full Text Available Estuary basin is a fertile area which has important role for sustaining many organisms from estuary and sea. Mould and other saprobic microorganisms have important role to decomposing organic material in estuary water. A study on diversity and abundance of mould inhabiting Muara Layang estuary sediment, Bangka Belitung Islands has not conduct before. The objective of this study is to investigate the abundance and diversity of mould inhabiting Muara Layang estuary sediment, Bangka Belitung Islands. The mould isolation was based on sample dilution method with Rose Bengal Cloramphenicol Agar mould isolation media. The abundance of mould was counted by measuring the average Colony Forming Unit (CFU/ml of all mould colonies which grown on isolation media by Total Plate Count (TPC method. The diversity of isolated mould was identified based on phenotypic characters by observing both of macroscopic and microscopic mould morphology. The result showed that the growth average of mould colonies is about (5-27.5 x102 CFU/mL. The result of mould identification showed that eight mould genera, Aspergillus (6 species, Chaetomium, Eupenicillium (3 species, Gliocladium, Paecilomyces, Penicillium (3 species, Scopulariopsis, Trichoderma (3 species, one group identified in class level (Coelomycetes, and three groups of unidentified sterile mould isolates were isolated.

  11. Freshwater scarcity effects on the aquatic macrofauna of a European Mediterranean-climate estuary.

    Science.gov (United States)

    González-Ortegón, Enrique; Baldó, Francisco; Arias, Alberto; Cuesta, Jose A; Fernández-Delgado, Carlos; Vilas, César; Drake, Pilar

    2015-01-15

    In the Mediterranean-climate zone, recurrent drought events and increasing water demand generally lead to a decrease in freshwater input to estuaries. This water scarcity may alter the proper function of estuaries as nursery areas for marine species and as permanent habitat for estuarine species. A 12-year data set of the aquatic macrofauna (fish, decapod and mysid crustaceans) in a Mediterranean estuary (Guadalquivir estuary, South Spain) was analysed to test if water scarcity favours the nursery function of regional estuaries to the detriment of permanent estuarine inhabitants. Target species typically displayed a salinity-related distribution and estuarine salinisation in dry years resulted in a general upstream community displacement. However, annual densities of marine species were neither consistently higher in dry years nor estuarine species during wet years. Exceptions included the estuarine mysid Neomysis integer and the marine shrimp Crangon crangon, which were more abundant in wet and dry years, respectively. High and persistent turbidity, a collateral effect of water scarcity, altered both the structural (salinity-related pattern) and functional (key prey species and predator density) community characteristics, chiefly after the second drought period of the analysis. The observed high inter-year environmental variability, as well as species-specific effects of water scarcity, suggests that exhaustive and long-term sampling programmes will be required for rigorously monitoring the estuarine communities of the Mediterranean-climate region. PMID:25005237

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

    International Nuclear Information System (INIS)

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

  13. Simulation of radionuclide fluxes from the Dnieper-Bug Estuary into the Black Sea

    International Nuclear Information System (INIS)

    To simulate the radionuclide flux from the Dnieper-Bug Estuary into the Black Sea the three-dimensional time-dependent flow and transport code THREETOX was used. The prognostic variables of the model are the three components of the velocity field, temperature, salinity, surface elevation, suspended sediment concentration and the radionuclide concentrations in the solute, suspended sediments and bottom deposition. The dispersion of 137Cs and 90Sr in the estuary and adjacent shelf area of the Black Sea over the first two years following the Chernobyl accident was reconstructed. The fluxes of radionuclides from the Dnieper-Bug Estuary into the Black Sea were estimated. The results are in reasonable agreement with the available measurements. It is shown that the differences between the 137Cs and 90Sr distributions specific to the Dnieper-Bug Estuary were due to the different geochemical behaviours of these radionuclides. The deviation from a linear correlation between salinity and dissolved 137Cs concentration in the estuary was shown to be due to exchange processes with contaminated bottom sediments. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

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

    Directory of Open Access Journals (Sweden)

    Curt Peterson

    2014-03-01

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

  15. Fingerprinting of bed sediment in the Tay Estuary, Scotland: an environmental magnetism approach

    Directory of Open Access Journals (Sweden)

    P. A. Jenkins

    2002-01-01

    Full Text Available Sediment fingerprinting is commonly used for sediment provenance studies in lakes, rivers and reservoirs and on hillslopes and floodplains. This investigation explores the mixing of terrestrial and marine-derived sediment in the Tay Estuary, Scotland, using mineral magnetic attributes for fingerprinting. Samples representative of the estuary sediments and of four sources (end-members were subjected to a suite of magnetic susceptibility and remanence measurements. Sediment samples from the beds of the Rivers Tay and Earn represented fluvial inputs while samples from the Angus and Fife coasts represented marine input. Multivariate discriminant and factor analysis showed that the sources could be separated on the basis of six magnetic parameters in a simple multivariate unmixing model to identify source contributions to estuarine bed sediments. Multi-domain magnetite signatures, characteristic of unweathered bedrock, dominate the magnetic measurements. Overall contributions of 3% from the River Earn, 17% from the River Tay, 29% from the Angus coast and 51% from the Fife coast source end-members, demonstrated the present-day regime of marine sediment derivation in the Tay Estuary. However, this conceals considerable spatial variability both along-estuary and in terms of sub-environments, with small-scale variations in sediment provenance reflecting local morphology, particularly areas of channel convergence. Keywords: bed sediment, environmental magnetism, fingerprinting, Tay Estuary, Scotland

  16. Historic and recent patterns in dissolved oxygen within the Yaquina Estuary (Oregon, USA): Importance of anthropogenic activities and oceanic conditions

    Science.gov (United States)

    Spatial and temporal patterns of dissolved oxygen (DO) in Yaquina Estuary, Oregon (USA) are examined using historic and recent data. There was a significant increasing trend in DO in the upstream portion of the estuary during the years 1960?1985. Historically, minimum dry season ...

  17. MAPPING SEAGRASS AND GREEN MACROALGAE DISTRIBUTIONS IN AN OREGON ESTUARY USING COLOR-INFRARED AERIAL PHOTOGRAPHY: 1997 & 1998

    Science.gov (United States)

    Aerial photograph surveys of Oregon's Yaquina Bay estuary were conducted during the summers of 1997 and 1998. Advantage was taken of daylight low tide conditions when most of the intertidal mudflats in the estuary were exposed. The absence of overlying water permitted the use o...

  18. MAPPING SEAGRASS AND GREEN MACROALGAE DISTRIBUTIONS IN AN OREGON ESTUARY USING COLOR INFRARED AERIAL PHOTOGRAPHY: 1997 & 1998

    Science.gov (United States)

    Aerial photograph surveys of Oregon's Yaquina Bay estuary were conducted during the summers of 1997 and 1998. Advantage was taken of daylight low tide conditions when most of the intertidal mudflats in the estuary were exposed. The absence of overlying water permitted the use o...

  19. E-Estuary: Developing a Decision-support System for Coastal Management in the Conterminous United States

    Science.gov (United States)

    Ready access to geographic information is needed to support management decisions for estuaries at local, state, regional, and national scales. The United States Environmental Protection Agency (US EPA) is developing e-Estuary, a decision-support system for coastal management. E...

  20. Allochthonous Organic Matter Subsidize the High Secondary Production of the Invasive Bivalve Corbicula fluminea in Minho Estuary (N-Portugal)

    Science.gov (United States)

    The Asian clam Corbicula fluminea is one of the most invasive species in freshwater ecosystems. In Minho estuary, this species colonize all the middle and upper part of the estuary, dominating the abundance, biomass and secondary production in River Minho tidal freshwater area (T...

  1. Contribution of N2O emissions to the atmosphere from Indian monsoonal estuaries

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, G.D.; Sarma, V.V.S.S.

    2013-01-01

    Estuaries are known to contribute a significant amount of nitrous oxide (N2O) to the atmosphere; however, the contribution from the Indian estuaries is unknown. We made an attempt to estimate emissions of N2O from the Indian...

  2. 75 FR 69622 - Request for Comments on the Draft Revision of the Estuary Habitat Restoration Strategy Prepared...

    Science.gov (United States)

    2010-11-15

    ...Estuary Habitat Restoration Strategy Prepared by the Estuary Habitat...to bring their resources (financial or in-kind) to the table...entities to carry out this Strategy, including the regional ocean...Technology The Act provides a financial incentive for the use of...

  3. Precipitation Frequency for Semiarid Southwest, USA - NOAA Atlas 14 Volume 1

    National Oceanic and Atmospheric Administration, Department of Commerce — This GIS grid atlas contains precipitation frequency estimates for the Semiarid Southwest based on precipitation data collected between 1893-2000. This atlas is an...

  4. Studies on the associates and parasites of zooplankton from southwest and southeast coasts of India

    Digital Repository Service at National Institute of Oceanography (India)

    Santhakumari, V.

    1997-01-01

    Associates and parasites of zooplankton from southwest and southeast coasts of India were studied. Among the epizoic forms two species of ciliates infesting copepods were new records from Indian waters. Eight species of suctorians were found epizoic...

  5. 2007 Southwest Florida Water Management District (SWFWMD) LiDAR: Hernando County

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset is one component of a digital terrain model (DTM) for the Southwest Florida Water Management Districts FY2006 Digital Orthophoto (B089) and LiDAR...

  6. Aggregation of Euphausia sibogae during summer monsoon along the southwest coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Jayalakshmi, K.J.; Jasmine, P.; Muraleedharan, K.R.; Prabhakaran, M.P.; Habeebrehman, H.; Jacob, J.; Achuthankutty, C.T.

    2011-01-01

    The influence of environmental parameters on the spawning aggregation of Euphausia sibogae was investigated along the southwest coast of India during the peak phase of summer monsoon 2005. The prevailing ecological conditions between the aggregation...

  7. Resource Assessment for Microalgal/Emergent Aquatic Biomass Systems in the Arid Southwest: Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Vigon, B. W.; Arthur, M. F.; Taft, L. G.; Wagner, C. K.; Lipinsky, E. S.; Litchfield, J. H.; McCandlish, C. D.; Clark, R.

    1982-12-23

    This research project has been designed to facilitate the eventual selection of biomass production systems using aquatic species (microalgal and emergent aquatic plant species (MEAP) which effectively exploit the potentially available resources of the Southwest.

  8. Dynamics of tidal and non-tidal currents along the southwest continental shelf of India

    Digital Repository Service at National Institute of Oceanography (India)

    Aruna, C.; Ravichandran, C.; Srinivas, K.; Rasheed, P.A.A.; Lekshmi, S.

    2007-01-01

    The tidal regimes over the continental shelves are often less documented due to lack of coastal water level data. This is of concern since continental shelves rule the global dissipation of tidal energy. The tides along the Southwest Indian shelf...

  9. Zooplankton of the southwest coast of India: abundance, composition, temporal and spatial variability in 1987

    Digital Repository Service at National Institute of Oceanography (India)

    Madhupratap, M.; Haridas, P.; Ramaiah, Neelam; Achuthankutty, C.T.

    1992-01-01

    During early southwest and northeast monsoon periods of 1967, zooplankton standing stocks and abundances were high all along the west coast of India. Swarms of zooplankton were common in the shelf areas resulting in a low diversity-high biomass...

  10. Microdistribution of zooplankton in the neustonic realm of the eastern Arabian Sea during southwest monsoon

    Digital Repository Service at National Institute of Oceanography (India)

    Achuthankutty, C.T.; Nair, S.R.S.; Nair, V.R.; Padmavati, G.; Madhupratap, M.

    1992-01-01

    During the southwest monsoon season of 1987, the zooplankton distributions in the neustonic realm (upper 50 cm) of the eastern Arabian Sea were studied and compared with those in the water column. The upper microlayer (upper 15 cm) had generally...

  11. Observational evidence of upwelling off the southwest coast of India during June-July 2006

    Digital Repository Service at National Institute of Oceanography (India)

    Lekshmi, S.; Smitha, B.R.; Revichandran, C.

    2007-01-01

    Considerable latitudinal variability exists in the forcing mechanisms and intensity of coastal upwelling along the southwest coast of India. Present work is based on the insitu observations conducted onboard FORV Sagar Sampada for 12 days along two...

  12. National Status and Trends: Bioeffects Program - Southwest Puerto Rico Chemical Contaminant Assessment Summary

    National Oceanic and Atmospheric Administration, Department of Commerce — The purpose of the project was to characterize the extent and magnitude of chemical contamination in southwest Puerto Rico, as part of a larger effort to link coral...

  13. 75 FR 65615 - Conditional Commitment for a Federal Loan Guarantee for Project Financing for Southwest Intertie...

    Science.gov (United States)

    2010-10-26

    ...that Great Basin implement all project-specific environmental protection...Plan for the Southwest Intertie Project 500-kV Transmission Line; SWIP...BLM ROW grant provisions for the life of the project. The NEPA analysis completed...

  14. Radioactivity and United Kingdom estuaries: an overview identifying research priorities

    International Nuclear Information System (INIS)

    The report consists of the results of an evaluation of research priorities for the environmental radioactivity of estuaries, (and near shore waters) of the United Kingdom. The format of this report is:(i) general conclusions for the future requirements for research in the field of environmental radioactivity; (ii) an overview of some specific recommendations for research; and (iii) an appendix in which a comprehensive evaluation of the research priorities for specific areas of research are given. On the basis that man is the prime target for concern and protection, special attention has been given to the environment in the vicinity of the British Nuclear Fuels (BNFL) reprocessing plant at Sellafield, Cumbria, which is the source of major releases of a variety of radionuclides into the natural environment. Subjects covered in the Appendix are: site factors; pathways to man; source term; hot particles; terrestrial inputs; surveys and monitoring; analysis; organics; field versus laboratory data; biology; bioaccumulation factors; some bioaccumulators of radioactivity; bioturbation; bacteria; genetics; natural change; sediment; resuspension; surfaces; Ksub(d) factors; pore liquids; diagenesis and the ageing processes; airborne transport of radionuclides; models; natural radioactivity; public opinion; recreation; the ICRP; the ALARA principle; decommissioning of nuclear power stations; identification of research requirements; environmental radioactivity - the national effort. (U.K.)

  15. Measuring hydrodynamics and sediment transport processes in the Dee Estuary

    Directory of Open Access Journals (Sweden)

    R. Bolaños

    2010-06-01

    Full Text Available The capability of monitoring and prediction in the marine environment provides information that may allow sustainable development of coastal and offshore regions. Therefore, the continuous measurement of environmental processes becomes an important source of information. The present paper shows data collected during 6 years, and in particular during 2008, in the Dee Estuary. The aim of the data collection is to improve the observations of the mobile sediments in coastal areas and its forcing hydrodynamics and turbulence. Data includes information from the deployment of instrumented rigs measuring sediment in suspension, currents, waves, sea level, sediment size and bedforms as well as cruise work including grab sampling, CTD profiles and side-scan sonar. The data cover flood and ebb tides during spring and neap periods with moderate and mild wave events, thus, having a good coverage of the processes needed to improve knowledge of sediment transport and the parameterizations used in numerical modelling. The data, in raw and treated, are being banked at BODC (British Oceanographic Data Centre, http://www.bodc.ac.uk/ which is the formal British organization for looking after and distributing data concerning the marine environment.

  16. Measuring hydrodynamics and sediment transport processes in the Dee estuary

    Directory of Open Access Journals (Sweden)

    R. Bolaños

    2010-03-01

    Full Text Available The capability of monitoring and predicting the marine environment leads to a more sustainable development of coastal and offshore regions. Therefore, the continuous measurement of environmental processes become an important source of information. The present paper shows data collected during 6 years, and in particular during 2008, in the Dee Estuary. The data aims to improve the observations of the mobile sediments in coastal areas and its forcing hydrodynamics and turbulence. Data involves the deployment of instrumented rigs measuring sediment in suspension, currents, waves, sea level, sediment size and bedforms as well as cruise work including grab sampling, CTD profiles and side-scan sonar. The data covers flood and ebb tides during spring and neap periods with moderate and mild wave events, thus, having a good coverage of the processes needed to improve knowledge of sediment transport and the parameterizations used in numerical modelling. The data, in raw and treated, is being banked at BODC (British Oceanographic Data Centre, http://www.bodc.ac.uk/ which is the formal British organization for looking after and distributing data concerning the marine environment.

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

    U.S. Bonneville Power Administration

    2008-08-01

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

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

    Directory of Open Access Journals (Sweden)

    Joseph N. Dominy Jr.

    2013-02-01

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

  20. An overview of tritium behaviour in the Severn Estuary (UK)

    International Nuclear Information System (INIS)

    Measurements of tritium (3H) activity in marine species in the Severn Estuary (UK) show concentrations significantly above those predicted by standard models. Concentration factors of 104 between seawater and marine species are observed; standard models assume a concentration factor of 1. In addition, the vast majority of activity is present in the form of organically bound tritium (OBT). The critical group dose from tritium - to consumers of local flounder - is estimated as ?36 ?Sv per annum. The measurements are related to the authorised release of wastes, via the sewer system, from the Amersham plc plant at Cardiff. The radiochemical plant manufactures a wide range of isotopically labelled compounds for use in life science research. The elevated levels of tritium observed in marine species have led to a programme of investigative work by specialist organisations. This paper describes the various definitions, measurements and significance of the term OBT. It also outlines the environmental observations and preliminary conclusions from the investigative programme to date. (author)

  1. Ostracoda and foraminifera as short-term tracers of environmental changes in very polluted areas: the Odiel Estuary (SW Spain)

    International Nuclear Information System (INIS)

    The analysis of 17 cores collected in the Odiel Estuary (SW Spain) permits delimiting the recent evolution of this zone during the past decades and the influence of natural and anthropogenic factors on the distribution of Ostracoda and Foraminifera. In the upper estuary, the coincidence of acid waters, prolonged subaerial exposure, and coarse sediments may explain the absence or the disappearance of these microorganisms during the industrial period (1966-1985) in the major part of this area. In the lower estuary, sedimentary evolution and industrial wastes are the main factors influencing both the distribution and trends of the populations of these two groups. Finally, the main changes observed in the marine estuary are due to the sedimentary effects of the construction of two banks and the dredging of the main estuarine channel. - In a polluted estuary, the meiofaunal assemblages experience different changes even in adjacent sedimentary environments, closely related to anthropogenic and natural causes

  2. Environmental controls on the speciation and distribution of mercury in surface sediments of a tropical estuary, India.

    Science.gov (United States)

    Chakraborty, Parthasarathi; Babu, P V Raghunadh

    2015-06-15

    Distribution and speciation of mercury (Hg) in the sediments from a tropical estuary (Godavari estuary) was influenced by the changing physico-chemical parameters of the overlying water column. The sediments from the upstream and downstream of the estuary were uncontaminated but the sediments from the middle of the estuary were contaminated by Hg. The concentrations of Hg became considerably less during the monsoon and post monsoon period. Total Hg concentrations and its speciation (at the middle of the estuary) were dependent on the salinity of the overlying water column. However, salinity had little or no effect on Hg association with organic phases in the sediments at downstream. Increasing pH of the overlying water column corresponded with an increase in the total Hg content in the sediments. Total organic carbon in the sediments played an important role in controlling Hg partitioning in the system. Uncomplexed Hg binding ligands were available in the sediments. PMID:25935803

  3. Hydrography and circulation off the west coast of India during the southwest monsoon 1987

    Digital Repository Service at National Institute of Oceanography (India)

    Shetye, S.R.; Gouveia, A.D.; Shenoi, S.S.C.; Sundar, D.; Michael, G.S.; Almeida, A.M.; Santanam, K.

    1990-01-01

    been the rough weather that occurs off the coast during the southwest monsoon. In 1987, two cruises were conducted making 13 sections covering the coast during the southwest monsoon. This paper provides an overview of the hydrography revealed... monsoon a shallow current along the west coast of India carries this water northward. Banse (1968, 1984) has pointed out that during this season vertical mixing due to winter convection occurs north of about 18N. The mixing is particularly effective...

  4. HIGHLIGHTS IN MATCHING LABOUR WITH LABOUR MARKET NEEDS IN THE REGION OF SOUTH-WEST OLTENIA

    OpenAIRE

    Tita, Victor

    2012-01-01

    This paper emphasizes the importance of several items in linking labour with labour market needs in the region of South-West Oltenia. By reference to the proposed research objectives, research instrument was a sociological survey, representing two sets of questions for two distinct target groups: unemployed and representatives of companies in the region. These instruments allowed an assessment of labour market in South-West Oltenia region, the present study highlighting some aspects of skills...

  5. Spatial variation and subcellular binding of metals in oysters from a large estuary in China.

    Science.gov (United States)

    Yu, Xiu-Juan; Pan, Ke; Liu, Fengjie; Yan, Yan; Wang, Wen-Xiong

    2013-05-15

    Pearl River Estuary (PRE) is the largest estuary in Southern China and there has been an increasing concern of metal pollution due to regional industrialization. In this study, we investigated the spatial variation of metal pollution (Ag, As, Cd, Cu, Pb, and Zn) as well as their subcellular handling in the oyster Crassostrea hongkongensis. Hot spots of metal contamination in the oysters were found in different sites, suggesting that there were different sources of metals in the estuary associated with industrial activity. Metals differed in their subcellular bindings in the oysters from different locations. Metal distribution in the biologically detoxified fraction decreased for Cu but increased for Zn with increasing contamination in the oysters. For Zn, there was a significant difference in its two detoxification pools (metal-rich granules and metallothionein-like proteins) in response to Zn contamination. The high Cd concentrations in oysters may carry a high Cd hazard to the consumers. PMID:23537691

  6. Variability in waterfowl distribution within hypertidal estuaries in relation to sediments

    International Nuclear Information System (INIS)

    The Severn and Mersey estuaries are two of Britain's most important sites for their waterfowl populations. It is therefore critical to fully understand the likely impacts of tidal power barrages on these populations in order to predict the long-term post-barrage populations that the estuaries could support. Previous studies have enabled four years of monitoring to be carried out on both estuaries using identical methodology. These studies have shown that there is a considerable degree of consistency in the waterfowl populations in some areas, although apparently less so in other areas. Studies of sediment mobility have not been carried out in ways which enable direct comparison of changes in sediment with changes in bird populations. This latest study was planned to permit such a comparison and to provide five years of detailed counts on the Severn and four years on the Mersey on the low tide distribution of waterfowl populations. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1985-07-20

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

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

    International Nuclear Information System (INIS)

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

  9. Social foraging and feeding environment of the black-crowned night heron in an industrialized estuary

    Science.gov (United States)

    Erwin, R.M.; Hatfield, J.S.; Link, W.A.

    1991-01-01

    A nesting colony of more than 300 pairs of Black-crowned Night-Herons in the Patapsco River estuary, Baltimore Harber, Maryland was monitored from May to July 1988. The departure direction and departure time of each Heron was recorded during mornjng and evening observations at the colony. In addition, individual Herons were followed to landing sites in the estuary with small boats and aircraft. Herons appear to be quite social in foraging and may concentrate their feeding in some of the most industrialized parts of the estuary. Night-Herons may prosper in urban environments because some of their prey are attracted to intense shoreline illumination at night. New quantitative methods were developed to cope with the lack of statistical independence when dealing with social species.

  10. A historical review and bibliometric analysis of research on estuary pollution.

    Science.gov (United States)

    Sun, Jinshui; Wang, Ming-Huang; Ho, Yuh-Shan

    2012-01-01

    A bibliometric method based on Science Citation Index-Expanded published by the Thomson Reuters was used to quantitatively assess the global estuary pollution research from 1991 to 2010. The main results were as follows: there had been a notable growth trend in publication outputs. Marine Pollution Bulletin was the most active journal. Environmental sciences were top popular subject categories. USA produced the most single, internationally collaborative, first authored and corresponding authored articles. The Chinese Academy of Sciences was the most productive institute for the total articles. Sediment was the most active research topic, which ranked 1st in article title, article abstract, author keyword, and KeyWords Plus analysis, respectively. Heavy metals received stable focus on a high degree in the field of estuary pollution research. Mostly refractory organic compounds (e.g. PAHs) became more active. Biomarkers and bioaccumulation both were active issues. Eutrophication of estuarine waters receives increasing concern in estuary pollution research. PMID:22119413

  11. Trace metals in the estuary of the Seine and its approaches

    International Nuclear Information System (INIS)

    The distribution and behaviour of trace metals (Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Ti, V and Zn) were studied in the waters and deposited or suspended sediments of the estuary and eastern bay of the Seine river. The various physico-chemical forms - hydrosoluble, exchangeable, chelated, organic forms, were determined by successive fractionations. The abundance of the ionic stock in the estuary cannot explain the decrease of trace metal contents by purely chemical processes. Mixing processes with open sea particles and release of metals induced by the erosion-sedimentation cycles resulting in sediment washing can explain the observations. Metals first trapped in the sediments are freed in the dissolved state; they can be expelled from the estuary and participate in the biological cycles. In the bay sediments, the trace metals were used as tracers of sediment masses, allowing to determine the river deposit areas. The human contribution to trace metal deposits in the Seine river bay was also estimated. (author)

  12. Dissolved Sr and its isotopes in estuaries of eastern coast of India: Impact of submarine groundwater discharge

    International Nuclear Information System (INIS)

    Full text: The isotopic compositions and concentrations of Sr in the dissolved phase of the Ganga (Hooghly), the Krishna, the Godavari and the Mahanadi estuaries are measured to study its behaviour in them. River end-members in these estuaries show significant variations with 87Sr/86Sr 0.7287, 0.7139, 0.7145 and 0.7166 and Sr concentration 0.81, 3.1, 1.3, and 1.4?mol.kg-1 respectively in the Hooghly, the Krishna, the Godavari and the Mahanadi estuaries. Sr concentrations in these estuaries vary linearly with salinity indicating conservative mixing between river and seawater with negligible supply from any third end-member and their Sr budget is dominated with contribution from seawater. Mixing plots of 87Sr/86Sr with 1/Sr in all these estuaries except the Mahanadi, however, display non-conservative behaviour with many data points in the estuaries deviating from the theoretical mixing line defined between individual river and Bay of Bengal seawater having 87Sr/86Sr 0.7092 and Sr content 88.0 ?mol.kg-1. The observed departure of estuary waters from the predictable mixing line between river and seawater requires supply of radiogenic Sr from third end-member in the Hooghly, the Krishna and Godavari estuaries. Addition source of radiogenic Sr in these estuaries could be either submarine groundwater discharge (SGD) or desorption from suspended particles. Conservative nature of Sr content with salinity hints towards the modification of their isotope composition without altering their content through SGD. Recycled seawater (part of SGD) could exchange their Sr isotope composition with aquifer solids and could act as an additional source of radiogenic Sr to these estuaries. This study suggests that submarine groundwater discharge plays an important role as an additional source of radiogenic Sr and could supply several trace elements and nutrients to the Bay of Bengal

  13. Valuing environmental water pulses into the Incomati estuary: Key to achieving equitable and sustainable utilisation of transboundary waters

    Science.gov (United States)

    Sengo, D. José; Kachapila, Albert; Zaag, Pieter van der; Mul, Marloes; Nkomo, Sakhiwe

    Upstream developments in the Incomati river basin, shared by South Africa, Swaziland and Mozambique, have altered downstream flows significantly. The frequency of small floods into the estuary has been reduced dramatically. This change in the flow regime has impacted on the state of the environment downstream, and the Incomati estuary in particular. The estuary requires fresh water pulses that naturally occur, and the resulting seasonal flooding of the plains. Resource-poor rural households depend on the goods and services that the estuary and flood plains provide such as wood, charcoal, building materials, fish and shrimp, wetland farming, and tourism. Alteration of the flow regime into the estuary has a negative impact on the state of the environment and hence on the goods and services the estuary yields; a phenomenon the people living near the estuary are keenly aware of. The article estimates the value of the goods and services that the estuary currently provides, that is under the conditions of a changed flow regime. A linear relationship is then assumed between fresh water pulses into the estuary and the goods and services it provides, so that the order of magnitude of the economic value of fresh water pulses into the estuary may be approximated. Various development scenarios in the Incomati basin are then considered, that have different upstream and downstream impacts on water availability, and the basin-wide benefits and costs are compared. The paper concludes that the principle of sharing the benefits derived from the water resources, rather than the water itself, as proposed by authors such as [Sadoff, C.W., Grey, D., 2002. Beyond the river: the benefits of cooperation on international rivers. Water Policy 4, 389-403], may be a feasible approach only if the less tangible benefits and functions, especially those of the environment, are assigned an appropriate value and corresponding priority.

  14. Dynamics of chromophoric dissolved organic matter in Mandovi and Zuari estuaries — A study through in situ and satellite data

    Science.gov (United States)

    Menon, Harilal B.; Sangekar, Nutan P.; Lotliker, Aneesh A.; Vethamony, P.

    The spatial and temporal distribution of absorption of chromophoric dissolved organic matter at 440 nm ( aCDOM (440)) in the Mandovi and Zuari estuaries situated along the west coast of India, has been analysed. The study was carried out using remotely sensed data, obtained from the Ocean Colour Monitor (OCM) on board the Indian Remote Sensing satellite — P4, together with in situ data during the period January to December 2005. Satellite retrieval of CDOM absorption was carried out by applying an algorithm developed for the site. A good correlation (R=0.98) was obtained between satellite derived CDOM and in situ data. Time series analysis revealed that spatial distribution of CDOM has a direct link with the seasonal hydrodynamics of the estuaries. The effect of remnant fresh water on CDOM distribution could be analysed by delineating a plume in the offshore region of the Zuari estuary. Though fresh water flux from terrestrial input plays a major role in the distribution of CDOM throughout the Mandovi estuary, its role in the Zuari estuary is significant up to the middle zone. Other processes responsible for feeding CDOM in both the estuaries are coastal advection, in situ production and resuspension of bottom settled sediments. The highest value of aCDOM(440) was observed in the middle zone of the Mandovi estuary during the post-monsoon season. The relation between aCDOM(440) and S (spectral slope coefficient of CDOM) could differentiate CDOM introduced in to estuaries through multiple sources. The algorithm developed for the Mandovi estuary is S=0.003 [ aCDOM(440) -0.7091] while for the Zuari estuary, S=0.0031 [ aCDOM(440) -0.777], respectively.

  15. Bioaccessible arsenic in the home environment in southwest England.

    Science.gov (United States)

    Rieuwerts, J S; Searle, P; Buck, R

    2006-12-01

    Samples of household dust and garden soil were collected from twenty households in the vicinity of an ex-mining site in southwest England and from nine households in a control village. All samples were analysed by ICP-MS for pseudo-total arsenic (As) concentrations and the results show clearly elevated levels, with maximum As concentrations of 486 microg g(-1) in housedusts and 471 microg g(-1) in garden soils (and mean concentrations of 149 microg g(-1) and 262 microg g(-1), respectively). Arsenic concentrations in all samples from the mining area exceeded the UK Soil Guideline Value (SGV) of 20 microg g(-1). No significant correlation was observed between garden soil and housedust As concentrations. Bioaccessible As concentrations were determined in a small subset of samples using the Physiologically Based Extraction Test (PBET). For the stomach phase of the PBET, bioaccessibility percentages of 10-20% were generally recorded. Higher percentages (generally 30-45%) were recorded in the intestine phases with a maximum value (for one of the housedusts) of 59%. Data from the mining area were used, together with default values for soil ingestion rates and infant body weights from the Contaminated Land Exposure Assessment (CLEA) model, to derive estimates of As intake for infants and small children (0-6 years old). Dose estimates of up to 3.53 microg kg(-1) bw day(-1) for housedusts and 2.43 microg kg(-1) bw day(-1) for garden soils were calculated, compared to the index dose used for the derivation of the SGV of 0.3 microg kg(-1) bw day(-1) (based on health risk assessments). The index dose was exceeded by 75% (18 out of 24) of the estimated As doses that were calculated for children aged 0-6 years, a group which is particularly at risk from exposure via soil and dust ingestion. The results of the present study support the concerns expressed by previous authors about the significant As contamination in southwest England and the potential implications for human health. PMID:17023026

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

    Energy Technology Data Exchange (ETDEWEB)

    Diefenderfer, Heida L.; Thom, Ronald M.; Borde, Amy B.; Roegner, G. C.; Whiting, Allan H.; Johnson, Gary E.; Dawley, Earl; Skalski, John R.; Vavrinec, John; Ebberts, Blaine D.

    2006-12-20

    This report is the second annual report of a six-year project to evaluate the cumulative effects of habitat restoration projects in the Columbia River Estuary, conducted by Pacific Northwest National Laboratory's Marine Sciences Laboratory, NOAA's National Marine Fisheries Service Pt. Adams Biological Field Station, and the Columbia River Estuary Study Taskforce for the US Army Corps of Engineers. In 2005, baseline data were collected on two restoration sites and two associated reference sites in the Columbia River estuary. The sites represent two habitat types of the estuary--brackish marsh and freshwater swamp--that have sustained substantial losses in area and that may play important roles for salmonids. Baseline data collected included vegetation and elevation surveys, above and below-ground biomass, water depth and temperature, nutrient flux, fish species composition, and channel geometry. Following baseline data collection, three kinds of restoration actions for hydrological reconnection were implemented in several locations on the sites: tidegate replacements (2) at Vera Slough, near the city of Astoria in Oregon State, and culvert replacements (2) and dike breaches (3) at Kandoll Farm in the Grays River watershed in Washington State. Limited post-restoration data were collected: photo points, nutrient flux, water depth and temperature, and channel cross-sections. In subsequent work, this and additional post-restoration data will be used in conjunction with data from other sites to estimate net effects of hydrological reconnection restoration projects throughout the estuary. This project is establishing methods for evaluating the effectiveness of individual projects and a framework for assessing estuary-wide cumulative effects including a protocol manual for monitoring restoration and reference sites.

  17. Radium isotopes in the Orinoco estuary and eastern Caribbean sea. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Moore, W.S.; Todd, J.F.

    1988-04-01

    Radium isotopes provide a means of identifying the source of freshened waters in the ocean and determining the time elapsed since these waters were in the estuary. We present evidence that, during April, waters from the Amazon mixing zone pass within 50 km of the mouth of the Orinoco mouth. These Amazon waters are characterized by a lower Ra228/Ra226 activity ratio than are waters from the Orinoco at similar salinities. Within the Caribbean Sea waters of Orinoco origin carry a characteristic radium signature including excess activities of Ra224. This isotope may be used to estimate the time elapsed since the waters were removed from contact with sediments. Current speeds based on Ra224 dating range from 5 to 20 cm/sec during April. Radium isotopes also provide an assessment of sediment mixing in the estuary. During low discharge (April), considerable mixing of older sediment by physical or biological processes or dredging maintained high activities of Ra228 in the estuary and produced the highest Ra228/Ra226 A. R.'s yet measured in any estuary. During the high discharge (Sept.) a large fraction of the Ra228 was derived from desorption from fresh sediment rather than mixing of older sediments. Activities of Ra224 were high in the estuary during both high and low discharge, indicating that considerable mixing of recently introduced sediment must occur during each period. The Ra224/Ra228 A. R.'s measured in Sept. imply that the same sediments were being resuspended during high discharge, and that there was little exposure of older sediments which had been stored in the estuary for months to years.

  18. Developing A New Predictive Dispersion Equation Based on Tidal Average (TA) Condition in Alluvial Estuaries

    Science.gov (United States)

    Anak Gisen, Jacqueline Isabella; Nijzink, Remko C.; Savenije, Hubert H. G.

    2014-05-01

    Dispersion mathematical representation of tidal mixing between sea water and fresh water in The definition of dispersion somehow remains unclear as it is not directly measurable. The role of dispersion is only meaningful if it is related to the appropriate temporal and spatial scale of mixing, which are identified as the tidal period, tidal excursion (longitudinal), width of estuary (lateral) and mixing depth (vertical). Moreover, the mixing pattern determines the salt intrusion length in an estuary. If a physically based description of the dispersion is defined, this would allow the analytical solution of the salt intrusion problem. The objective of this study is to develop a predictive equation for estimating the dispersion coefficient at tidal average (TA) condition, which can be applied in the salt intrusion model to predict the salinity profile for any estuary during different events. Utilizing available data of 72 measurements in 27 estuaries (including 6 recently studied estuaries in Malaysia), regressions analysis has been performed with various combinations of dimensionless parameters . The predictive dispersion equations have been developed for two different locations, at the mouth D0TA and at the inflection point D1TA (where the convergence length changes). Regressions have been carried out with two separated datasets: 1) more reliable data for calibration; and 2) less reliable data for validation. The combination of dimensionless ratios that give the best performance is selected as the final outcome which indicates that the dispersion coefficient is depending on the tidal excursion, tidal range, tidal velocity amplitude, friction and the Richardson Number. A limitation of the newly developed equation is that the friction is generally unknown. In order to compensate this problem, further analysis has been performed adopting the hydraulic model of Cai et. al. (2012) to estimate the friction and depth. Keywords: dispersion, alluvial estuaries, mixing, salt intrusion, predictive equation

  19. Seasonal movements of American horseshoe crabs Limulus polyphemus in the Great Bay Estuary, New Hampshire (USA

    Directory of Open Access Journals (Sweden)

    Susanne Y. SCHALLER, Christopher C. CHABOT, Winsor H. WATSON III

    2010-10-01

    Full Text Available The goal of this study was to determine the year round movement patterns of American horseshoe crabs, Limulus polyphemus, in the Great Bay Estuary, New Hampshire (USA by using acoustic telemetry to track the movements of 37 adult Limulus, for periods ranging from 2 to 31 months. During the winter (December-March horseshoe crabs moved very little. In the spring, when water temperatures exceeded 11oC, horseshoe crabs moved at least 1 km further up into the estuary to shallower subtidal areas about a month prior to spawning. The mean distance traveled during spring migrations was 2.6 ± 0.5 (n=20 km up the estuary. Mating occurred in May and June and during these months animals spent most of their time in shallow subtidal areas adjacent to mating beaches. In the summer (July-August, animals moved 1.5 ± 0.5 (n=26 km down the estuary, towards the ocean, and ranged widely, using extensive portions of the estuary. In the fall (September-November movement was more limited (0.5 ± 0.5 km; n = 24 while animals settled into wintering locations, where they remained until spring. The mean annual linear range for all animals was 4.5 ± 0.3 km (n =35 and the maximum distance traveled by an individual horseshoe crab within one year was 9.2 km. There was no evidence that any of the horseshoe crabs tracked during this study left the estuary [Current Zoology 56 (5: 587–598, 2010].

  20. Fate of sulfonamide resistance genes in estuary environment and effect of anthropogenic activities.

    Science.gov (United States)

    Lu, Zihao; Na, Guangshui; Gao, Hui; Wang, Lijun; Bao, Chenguang; Yao, Ziwei

    2015-09-15

    With the exacerbating problem of antibiotic resistance, antibiotic resistance genes (ARGs) as emerging contaminants are found at elevated levels in inland aquatic environments, especially in regions of intensive agricultural and urban activity. However, little quantitative data exist on the migration and attenuation of ARGs in estuary ecosystem, which is central to predicting their fate after release into marine environment. Moreover, the relevance of multiple chemical contaminants and water quality constituents should be understood to amplify and attenuate antibiotic resistance levels. To determine the prevalence and examine the fate of sulfonamide ARGs (sul-ARGs) in two estuaries under different effects of anthropogenic activities, we analyzed the sul-ARGs (sul1, sul2, and sul3), class 1 integrons (int1), and bacterial biomass in surface water samples from Daliaohe and Liaohe river estuaries. We also evaluated five types of antibiotics, heavy metals, and various bulk water quality constituents. Results showed that sul-ARGs were widespread in Daliaohe and Liaohe river estuaries, but the distribution did not correlate with the concentration of sulfonamides. Significant reduction in the abundance of sul-ARGs was also observed with increased salinity. Nevertheless, the trend in the change of concentrations of sul-ARGs was different in the two estuaries. Statistical analysis of the results indicated that several metals were significantly and positively correlated with sul-ARGs. Pearson's correlation coefficients were higher than those determined between antibiotic residues and sul-ARGs. Furthermore, the relative abundance of sul-ARGs was significantly and positively correlated with the relative abundance of int1 which suggested that the propagation of sul-ARGs was facilitated by class 1 integrons in estuaries. PMID:25981941

  1. Macrofaunal communities in the habitats of intertidal marshes along the salinity gradient of the Schelde estuary

    Science.gov (United States)

    Hampel, Henrietta; Elliott, M.; Cattrijsse, A.

    2009-08-01

    The macrobenthos is important in benthic remineralization processes; it represents a trophic link and is also often used as a bio-indicator in monitoring programs. Variations of the environmental parameters strongly influence the structure of the macrobenthic communities in the marshes and since macrobenthos is the most important food item for marsh-visiting fish species in the Schelde, the variation in food resources can have a strong effect on the higher trophic level. The present study deals with the variation in macrobenthic communities in different habitats of intertidal marshes along the salinity gradient and the differences between the marsh creeks and the intertidal part of the estuary. The study measured density and species richness together with the biomass, and sampled a large intertidal channel and a smaller creek within five marshes along the salinity gradient of the Schelde estuary every six weeks between May and October in 2000. The small creeks had a smaller grain size and higher organic matter content than those in the large channel although the differences in the environmental parameters did not explain the different communities in the two habitats. Marshes had distinct macrobenthic communities but the abundance of macrofauna fluctuated along the estuary without an identifiable spatial trend. In contrast, the total biomass increased towards the euhaline area due to the domination of Nereis diversicolor. Diversity showed a significant positive correlation with the salinity. Comparison of the macrofaunal communities in the marsh with those on the intertidal flats of the estuary indicated similar trends in density, biomass and diversity along the salinity gradient. The density was similar in both habitats whereas biomass was much higher in the intertidal habitats of the estuary, partly due to the higher biomass of molluscs and annelids. Diversity indices were higher in the marsh, and the freshwater area had more species than in the estuary.

  2. Composition, abundance, distribution and seasonality of larval fishes in the Sundays Estuary, South Africa

    OpenAIRE

    Sutherland, K.; Nadine Strydom; Wooldridge, T. H.

    2013-01-01

    The larval fish assemblage was studied in the permanently open Sundays Estuary on the south-east coast of South Africa.  Seasonal samples were collected between winter 2007 and autumn 2009 at eight sites along the estuary by means of boat-based plankton tows using two modified WP2 nets.  Salinity ranged from 1.5 - 36.5 and temperature from 11.6 - 26.8ºC during the study period.  A total of 8174 larval and early juvenile fishes were caught, representing 12 families and 23 taxa.  The Clupe...

  3. The effects of increased freshwater inflow on metal enrichment in selected Eastern Cape estuaries, South Africa

    Scientific Electronic Library Online (English)

    KK, Orr; JE, Burgess; PW, Froneman.

    2008-01-01

    Full Text Available The concentrations of select metals (Cd, Co, Cu, Fe, Pb, Ni and Zn) within the water column and sediment of the permanently open Kariega Estuary and temporary open/closed Riet and East Kleinemonde Estuaries were investigated during a dry and a wet season. Enrichment factors (EFs), using Fe as a refe [...] rence element, and baseline linear regression models for metals vs Fe were used to assess the extent of metal enrichment in the sediments. The results of the study indicate that Cd, Co Ni and Pb were enriched above baseline concentrations (1.0

  4. The effects of organic inputs to estuaries on overwintering bird populations and communities

    International Nuclear Information System (INIS)

    This study investigates the relationship between changes in organic inputs to river estuaries and other coastal intertidal areas, and changes in the populations of waterfowl in these habitats. This is done in the context of tidal barrage construction, where barrage construction and operation may coincide with the cleaning of estuarine water. A thorough review of the literature is undertaken to determine the current status of knowledge of bird/organic-enrichment interactions. The use of multivariate statistics for identifying gradients in similarity between bird communities (specifically waders) of different estuaries, irrespective of geographic locations is investigated. (UK)

  5. USGS science at work in the San Francisco Bay and Sacramento-San Joaquin Delta estuary

    Science.gov (United States)

    Shouse, Michelle K.; Cox, Dale A.

    2013-01-01

    The San Francisco Bay and Sacramento-San Joaquin Delta form one of the largest estuaries in the United States. The “Bay-Delta” system provides water to more than 25 million California residents and vast farmlands, as well as key habitat for birds, fish, and other wildlife. To help ensure the health of this crucial estuary, the U.S. Geological Survey, in close cooperation with partner agencies and organizations, is providing science essential to addressing societal issues associated with water quantity and quality, sediment transportation, environmental contamination, animal health and status, habitat restoration, hazards, ground subsidence, and climate change.

  6. Behaviour of U-Isotopes in an Estuary Affected by Acid Mine Drainage and Industrial Releases

    International Nuclear Information System (INIS)

    Tinto and Odiel rivers (SW of Spain) is an ecosystem of great interest that is seriously affected by acid mine drainage (AMD) from long-term mining activities (pH < 3). Additionally, a large industrial complex is located in the surroundings of this estuary and Huelva town, which includes two phosphate rock processing plants that produce about 3 millions of tons per year of a byproduct called phosphogypsum (PG) containing high U-series radionuclides concentrations. For these reasons, the estuary of Huelva is one of the most heavy metals and radionuclides polluted estuarine systems in Europe with extremely low pH.

  7. STUDY ON THE EFFECTS OF TIDE ON SEDIMENTATION IN ESTUARIES OF THE NIGER DELTA, NIGERIA

    Directory of Open Access Journals (Sweden)

    Charles Chizom Dike

    2012-12-01

    Full Text Available Niger Delta Estuary Nigeria is influenced by tidal currents due to its proximity to the Atlantic Ocean. Tides in the region are mostly semidiurnal, having two high and low water levels each day, with tidal prism ranging from 0.4 to 1.5m. The effects of tidal current reduces with distance inland and are strongest at the inlets with velocity varying from 2.0 to 5.0m/sec. The depth of the Estuary Rivers is controlled by the strength of the tidal currents; areas very close to ocean with stronger tidal effect are very deep; while shallow rivers predominates the hub of the estuary. Tidal current provides the steady supply of energy that moves sediments in and out of the estuaries from the seashore thus determing river bathymetric shapes through modification of existing morphology by eroding or depositing of sediments along the river course, while further sediment deposition is curtailed at the bottom as the estuary gets shallower due to the increasing stirring by waves. Despite all the sediment coming into the estuaries, many canals in the region have remained as open-water bodies, even after some thousand years. This suggests that, the interaction between the tide and the shape of the canal floor helps to regulate long-term sedimentation. However, the Dredged Canals in the Niger Delta estuaries have suffered high siltation rates because of excessive supply of sediments generated by storm/flood waters from upland and disposal of spoils from dredging activities into the water bodies, which causes some imbalance in the estuarine self-cleaning mechanism. Sediment loads entering the mangrove swamp environment are essentially polycentric; suspended fines enter the system both from the sea and the rivers. A mathematical model was formulated to predict and study the behavior of the sea bed levels, tidal heights and currents, in other to understand how they interact with each other. The model was calibrated using data obtained from local field observations and measurements. The model results compares favorably with the field results, with average correlation coefficient of 0.9 (see figures 2-13.The result showed that Niger Delta estuaries erode, accrete, or remain stable, depending on the rate at which sediment is supplied or removed from them by flood waters and tidal currents.

  8. Mercury distribution in contaminated surface sediments from four estuaries, Khuzestan shore, north part of Persian Gulf.

    Science.gov (United States)

    Sarasiab, Abdolah Raeisi; Hosseini, Mehdi; Mirsalari, Zohreh

    2014-11-01

    The distribution of mercury in surface sediment from four estuaries along the Khuzestan shore, north part of Persian Gulf, was measured. The concentration of mercury varied among sampling stations (p organic matter (16.6 %) > easily and exchangeable (2.2 %) > acid reduction (0.8 %). I geo values calculated for mercury (1.5) showed higher values in Musa estuary than in the other stations. The bioavailability of mercury in sediments could be controlled by physicochemical factors such as pH, oxidation and reduction potential, organic carbon content and cation exchange capacity. PMID:25186811

  9. Oceanography and Quaternary geology of the St. Lawrence Estuary and the Saguenay Fjord

    International Nuclear Information System (INIS)

    The St. Lawrence Estuary is an environment marked by important freshwater discharge and well stratified water masses, recording large seasonal contrast in surface waters from freezing conditions in winter to temperate conditions in summer due to a very strong seasonal cycle in overlying air temperature. High productivity takes place in the pelagic and benthic environments, where a recent trend toward bottom water hypoxia is observed. The area was profoundly marked by the Quaternary glaciations. Thick glaciomarine sequences dating from the last deglaciation are observed in the Estuary and along the shores, whereas a relatively thin layer (a few meters at most) of hemipelagic mud was deposited during the Holocene.

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2005-07-01

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

  12. Many southwest hosptials will receive decreased CMS reimbursement

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2013-11-01

    Full Text Available No abstract available. Article truncated at 150 words. More hospitals are receiving penalties than bonuses in the second year of the Centers for Medicare and Medicaid Services’ (CMS quality incentive program, and the average penalty is steeper than last year according to a report from Jordan Rau in Kaiser Health News (1. Southwest hospitals reflect that trend with New Mexico and Arizona exceeding the US average both in percentage of hospitals receiving penalties and the average size of the penalty (Table 1. Colorado approximated the national averages (Table 1. Most hospitals are gaining or losing <0.2% but in some instances the penalties are substantial. Gallup Indian Medical Center in New Mexico, a federal government hospital on the border of the Navajo Reservation, will be paid 1.14 percent less for each patient and New Mexico’s average of a -0.31% decline in reimbursement are the largest changes nationally. “This program is driving what we want in health care,” said Dr. …

  13. Outreach and Financial Sustainability of Microfinance Banks in Southwest Nigeria

    Directory of Open Access Journals (Sweden)

    Musa A. Olasupo

    2014-01-01

    Full Text Available Microfinance Banks (MFBs in Nigeria are still a far cry from meeting their potentials as instrument of genuine economic development through the empowerment of the economic active poor whose core economic activities are located along the agricultural value chains. We examined the outreach and financial sustainability of MFBs to ascertain how well they have contributed to the financial intermediation process and also provide insight into their readiness as catalyst for the financial inclusion strategy. We measured outreach through technical efficiency and financial sustainability through economic efficiency using Data Envelopment Analysis for the activities of 86 MFBs in South-West, Nigeria. We observed a mean annual technical efficiency score of 0.464 and 30.23% of the sampled MFBs had technical efficiency score estimates of between 0.61 and 1.0. The mean economic efficiency score was 0.055 with a maximum of 2 MFBs on the economic efficiency score range of 0.81 and 1.0 over the study period. The mean economic efficiency of MFBs located in commercial areas was 0.0712 greater than the mean economic efficiency of their counterparts in the agrarian areas. Overall, the study depicted the Nigerian Microfinance sub-sector to be at its infancy (stage and hence needs to be nurtured to achieve its potentials. 

  14. Unlocking the Secrets of the Geodynamo: the Southwest Pacific Key

    Science.gov (United States)

    Turner, G. M.; Greve, A.; Kinger, R.; de Gelder, G.; Fitzsimons, S.; Howarth, J. D.; Hill, M. J.; Nilsson, A.; Sheppard, P.

    2014-12-01

    Three years ago we embarked on a project to boost the coverage of palaeosecular variation data from the Southwest Pacific region, and so to provide the means to enhance global and regional field models, dating tools derived from them, and understanding of features of the geodynamo, particularly beneath this region of the Earth's surface. Here we present our progress to date, including lake sediment records covering the entire Holocene, archaeomagnetic data from Maori cooking ("hangi") stones dating back to the earliest occupation of New Zealand, archaeointensities from Lapita pottery from the Pacific Islands (Fiji, Tonga and Papua New Guinea) dating back to ca 3000 BP, and palaeomagnetic directions and intensities from volcanic rocks and lava flows of the North Island of New Zealand. Central to the project is a composite lake sediment record, constrained by a high-resolution radiocarbon-based chronology, which provides a complete record of declination, inclination and relative palaeointensity for New Zealand through the Holocene. This is complemented by directions and absolute intensities from archaeological materials, most of which have associated radiocarbon age control, and lavas with 40Ar-39Ar age constraints, the rock magnetism and analytical details of which are discussed in accompanying posters. The overall picture reveals several large amplitude directional swings in the early Holocene magnetic field, followed by relatively low amplitude secular variation for several thousand years leading to the present trend to increasingly easterly declination and steep inclination as the south magnetic pole moves further off the Antarctic continent towards New Zealand.

  15. Sequence stratigraphic control on prolific HC reservoir development, Southwest Iran

    Science.gov (United States)

    Lasemi, Y.; Kondroud, K.N.

    2008-01-01

    An important carbonate formation in the Persian Gulf and the onshore oil fields of Southwest Iran is the Lowermost Cretaceous Fahliyan formation. The formation in Darkhowain field consists of unconformity-bounded depositional sequences containing prolific hydrocarbon reservoirs of contrasting origin. Located in the high stand systems tract (HST) of the lower sequence encompassing over 200m of oil column are the most prolific reservoir. Another reservoir is over 80m thick consisting of shallowing-upward cycles that are best developed within the transgressive systems tract of the upper sequence. Vertical facies distribution and their paleobathymetry and geophysical log signatures of the Fahliyan formation in the Darkhowain platform reveal the presence of two unconformity-bounded depositional sequences in Vail et al., Van Wagoner et al., and Sarg. The Fahliyan formation mainly consists of platform carbonates composed of restricted bioclastic lime mudstone to packstone of the platform interior, Lithocodium boundstone or ooid-intraclast-bioclast grainstone of the high energy platform margin and the bioclast packstone to lime mudstone related to the off-platform setting.

  16. The chimpanzees of Oluwa Forest Reserve, southwest Nigeria

    Directory of Open Access Journals (Sweden)

    B.G. Ogunjemite

    2012-12-01

    Full Text Available The lack of accurate information on the population of chimpanzees (Pan troglodytes is a cause for concern on their conservation and management in Southwest Nigeria. We conducted surveys on the chimpanzees of Oluwa Forest Reserve, Ondo State between the month of September 2011 and February 2012. We used the combination of recce survey and GIS mapping to determine Chimpanzees’ locations in the reserve. Chimpanzee distribution was confined to the central portion of the OA2 axis of the reserve. This portion is approximately 39.22km2 representing 5.78% of the total size of the original area of the reserve. Four sightings of Chimpanzee groups were achieved with an average of 9.50 ± 1.55 individuals observed. We observed nests built on rock platforms. The numbers of tree nests observed at sleeping sites were usually fewer than the number of animals seen, indicating that not all of them build nest on trees at their nesting sites. These observations were new in nesting behavior of chimpanzees across Nigeria and it is postulated to be on account of insecurity and deprivation of essential material necessary for nesting in their night sleeping sites. We explained this on the conceptual frame work of psycho-infrastructuralism model.

  17. Estimate of winter wheat yield from ERTS-1. [southwest Kansas

    Science.gov (United States)

    Morain, S. A.; Williams, D. W.

    1974-01-01

    A model for estimating wheat yield per acre has been applied to acreage estimates derived from ERTS-1 imagery to project the 1973 wheat yields for a ten county area in southwest Kansas. The results (41.04 million bushels) are within 3 per cent of the preharvest estimates for the same area prepared by the USDA Statistical Reporting Service (39.91 million bushels). The projection from ERTS data is based on a visual enumeration of all detectable wheat fields in the study area and was completed while the harvest was in progress. Visual identification of winter wheat is readily achieved by using a temporal sequence of images (band 5 for Sept.-Oct.; band 5 for Dec.-Jan.; and band 5 and 7 for March-April). Identification can be improved by stratifying the project area into subregions having more or less homogeneous agricultural practices and crop mixes. By doing this, small changes in the spectral appearance of wheat related to soil type, irrigation, etc. can be accounted for. The interpretation rules developed by visual analysis can be automated for rapid computer surveys.

  18. Turtle riders: remoras on marine turtles in Southwest Atlantic

    Scientific Electronic Library Online (English)

    Ivan, Sazima; Alice, Grossman.

    2006-03-01

    Full Text Available Uma visão geé apresentada sobre uma relação pouco documentada entre vertebrados recifais no Atlântico Sul Ocidental: rêmoras (Echeneidae) associadas a tartarugas marinhas. Duas espécies de rêmora ou pegador (Echeneis naucrates e Remora remora) e quatro de tartarugas (Caretta caretta, Chelonia mydas, [...] Eretmochelys imbricata e Dermochelys coriacea) são aqui registradas em associações simbiônticas para o Atlântico Sul Ocidental. Echeneis naucrates foi registrada tanto na costa como em ilhas oceânicas, ao passo que R. remora foi registrada somente em ilhas oceânicas e região pelágica. A associação entre rêmoras e tartarugas é habitualmente considerada como forese, embora forrageamento, por parte das rêmoras, também esteja envolvido neste tipo de simbiose. Esta associação parece ser rara no Atlântico Sul Ocidental. Abstract in english An overview is presented for a poorly documented relationship between reef vertebrates in Southwest Atlantic: remoras (Echeneidae) associated with marine turtles. Two remora species (Echeneis naucrates and Remora remora) and four turtle species (Caretta caretta, Chelonia mydas, Eretmochelys imbricat [...] a, and Dermochelys coriacea) are here recorded in symbiotic associations in the SW Atlantic. Echeneis naucrates was recorded both on the coast and on oceanic islands, whereas R. remora was recorded only at oceanic islands and in the open sea. The remora-turtle association is usually regarded as an instance of phoresis (hitchhiking), albeit feeding by the fish is also involved in this symbiosis type. This association seems to be rare in SW Atlantic.

  19. Winter pairs of ruddy shelducks at Lashihai Lake, southwest China.

    Science.gov (United States)

    Quan, Ruichang; Cui, Liangwei

    2013-04-01

    It has been suggested that pairing behavior during winter in migratory ducks represents a trade-off between costs (defense of the female) and benefits (early access to females). To investigate the benefits and costs for both sexes in wintering pairs of ruddy shelducks (Tadorna ferruginea), we compared time budgets for paired males and females, and surveyed the sex ratio of the birds wintering at Lashihai Lake, southwest China. The behavior of the paired ruddy shelducks was monitored for 5 activity types: feeding, resting (including sleeping), preening, drinking and warning. Feeding was the most dominant activity. The feeding time of both sexes increased as the winter season progressed. However, the paired females always spent significantly more time feeding and less time warning than the paired males. Paired ruddy shelducks had access to better feeding grounds than unpaired individuals, resulting in a food benefit for paired individuals over single individuals. Because the sex ratio of the wintering population was strongly male biased (M:F = 1.44:1.00), the paired male also gained the benefit of accessing a female in advance of the breeding season. PMID:23621471

  20. Turtle riders: remoras on marine turtles in Southwest Atlantic

    Directory of Open Access Journals (Sweden)

    Ivan Sazima

    2006-03-01

    Full Text Available An overview is presented for a poorly documented relationship between reef vertebrates in Southwest Atlantic: remoras (Echeneidae associated with marine turtles. Two remora species (Echeneis naucrates and Remora remora and four turtle species (Caretta caretta, Chelonia mydas, Eretmochelys imbricata, and Dermochelys coriacea are here recorded in symbiotic associations in the SW Atlantic. Echeneis naucrates was recorded both on the coast and on oceanic islands, whereas R. remora was recorded only at oceanic islands and in the open sea. The remora-turtle association is usually regarded as an instance of phoresis (hitchhiking, albeit feeding by the fish is also involved in this symbiosis type. This association seems to be rare in SW Atlantic.Uma visão geé apresentada sobre uma relação pouco documentada entre vertebrados recifais no Atlântico Sul Ocidental: rêmoras (Echeneidae associadas a tartarugas marinhas. Duas espécies de rêmora ou pegador (Echeneis naucrates e Remora remora e quatro de tartarugas (Caretta caretta, Chelonia mydas, Eretmochelys imbricata e Dermochelys coriacea são aqui registradas em associações simbiônticas para o Atlântico Sul Ocidental. Echeneis naucrates foi registrada tanto na costa como em ilhas oceânicas, ao passo que R. remora foi registrada somente em ilhas oceânicas e região pelágica. A associação entre rêmoras e tartarugas é habitualmente considerada como forese, embora forrageamento, por parte das rêmoras, também esteja envolvido neste tipo de simbiose. Esta associação parece ser rara no Atlântico Sul Ocidental.

  1. The relict forests of Northwest Peru and Southwest Ecuador

    Directory of Open Access Journals (Sweden)

    Maximilian Weigend

    2013-05-01

    Full Text Available The forest fragments or relict forests on the Western slopes of the Andes in northwest Peru and in south-west Ecuador are fragile ecosystems, which were largely continuous at some stage in the past. The importance and uniqueness of these forests as «refuges» and stable habitats roots partly in their complex diversity and their high levels of endemicity. These in turn are the outcome of a complex topography and ecology. In this introductory chapter 12 studies are analysed, which were presented at the Taller sobre Bosques Relictos de la Vertiente Occidental Andina del Norte del Perú y Sur del Ecuador in May 2004 at the X CONABOT, Trujillo-Perú. This helps to consolidate and update our knowledge on these over 20 forests fragments in northern Peru and two previously unknown fragments are presented for the first time: Bosque La Oscurana (Cajamarca and Kañaris (Lambayeque. Some ideas are exposed on the the relationships between the relict forests, how to analyse their dynamics, how to characterize their structure and how their conservation may be achieved. It is proposed that crucial elements in a conservation of these forests are a urgently inventorizing them to demonstrate their high diversity b emphasizing their economic potential with respect to the abundance of phytogenetic ressources c evaluating their role as catchment areas for the rivers which are the primary source of water for agriculture and urban life on the coast.

  2. Haemocytic leukemia in Prince Edward Island (PEI) soft shell clam (Mya arenaria): Spatial distribution in agriculturally impacted estuaries

    International Nuclear Information System (INIS)

    Intensive farming of potatoes in Prince Edward Island (PEI) relies on the repeated and widespread application of fertilizers and pesticides. In PEI the main potato farming areas are in close proximity and drain directly to estuaries. Runoff from high agricultural activity watersheds could impact benthic organism health in the depositional zone of downstream estuaries. The estuarine filter feeder Mya arenaria (soft-shell clam) could be particularly vulnerable to both particle-adsorbed and water soluble contaminants. M. arenaria is susceptible to haemocytic leukemia. In May 2009, we established that heavily proliferated leukemia (HPL) prevalence was generally higher in PEI estuaries located downstream of high intensity potato farming (Dunk and Wilmot estuaries) watersheds than in estuaries downstream of lower intensity areas. Using Mab-1E10 based immunocytochemistry we observed that leukemic haemocytes from the Dunk and Wilmot estuaries were 1E10 negative whereas those from the Ox/Sheep estuary (low potato farming intensity) were 1E10 positive. The expression of genes in the p53 tumour suppressor pathway enabled us to differentiate groups of leukemic and normal M. arenaria, validating our diagnoses. In October 2009, we confirmed that HPL prevalence was elevated in the Dunk and Wilmot estuaries compared to reference (Souris River). Moreover, leukemia prevalence declined with distance from the river mouths along transects through the Dunk and Wilmot estuaries. The pesticithe Dunk and Wilmot estuaries. The pesticides ß-endosulfan and ?-endosulfan were detected in surface sediments from the Dunk and Wilmot estuaries, but not in sediments from either the Souris River or several other lower intensity potato farming watersheds. Our study provides evidence of an association between intensity of potato farming and prevalence of clam leukemia at downstream estuaries in PEI. - Highlights: ? We examined leukemia prevalence in PEI clams Mya arenaria. ? Prevalence was generally higher downstream of high intensity potato farming. ? Leukemia prevalence declined with distance from source in two impacted estuaries. ? Proteins, gene expression and immunology confirm diagnosis of disease. ? Intensive potato farming may contribute to prevalence of clam leukemia in PEI.

  3. Bedforms and sediment distribution in the Minho estuary (Northern Portugal)

    Science.gov (United States)

    Duarte, Henrique

    2010-05-01

    Here are presented preliminary results of the MINHO09 cruise, carried out within the scope of the paleoclimatic research task of the MINHO project (PROYECTO 0234_NATURA_MIÑO_MINHO). Bed features and sediment distribution were mapped in the Minho estuary (Northern Portugal) using a dual frequency sidescan sonar mosaic (EdgeTech 4200-MP), and bottom sediment texture data from 71 sites sampled with a winch operated sediment grab (Van Veen type). The survey was done within 5 days, in low flow energy conditions of summer dry weather and neap tides, close to optimal conditions for correlating the acoustic imagery with the bottom sediment data. A DGPS (Omnistar 8200HP) was used to determine the horizontal position of the acoustic imagery and the sediment sample sites with sub-meter accuracy. Uncorrected water depths were determined with a depth echo-sounder (Odom HYDROTRAC echo sounder), and the water depths referred to the local datum was later determined using data from a tidal gauge (Valeport model 740) deployed specifically for this survey. Overall the sampled sediments were mostly poorly calibrated, with grain sizes ranging from gravel to mud coexisting in the same sample, probably reflecting the great seasonal contrast in flow conditions in the Minho River. The predominantly muddy sediments were observed along the river margins (frequently charged with gas) and, locally, along relatively deeper portions of the channel bed. The bedforms observed in the sidescan sonar data are dominated by 2D and 3D dunes and ripples. There are several locations were the bedforms suddenly change from larger dunes (wave lengths greater than 5m) to smaller ripples (wave lengths smaller than 1m). These changes may be related to the occurrence of supercritical flow conditions (Froude number > 1): hydraulic jumps in places were there is a sudden change in depth without any change in channel width, or chutes and pools in places were there is a sudden change in channel width; future work is planed to answer this question by doing a detailed comparison of the bedforms, sediment texture and bathymetric data (data that was not yet available at the time of writing of this abstract). Fan shaped echoes and associated sediment landslide scars are frequently observed near steeper channel margins and at the foot of ship docking ramps, evidence of sediment input directly from the river margins. The muddy river margins frequently exhibited a stair case pattern of low reflectivity in the horizontal segments, and strong linear echoes in the steeper portions of the "stair case" margin. This same pattern was also observed in the muddy margins of a regularly dredged channel that crosses a large area of sand bars in the middle of the estuary. The preliminary interpretation of this pattern is that it is caused by the deposition and slumping of muddy sediments along the margins in the low energy conditions that were predominant during the spring and summer season prior to the survey. Sea grass is clearly recognizable in the form of densely packed irregular lines of strong echoes, and is abundant upriver towards Tuy, probably outside the tidal influence. Some of the acoustic "speckle" found in the sonar imagery may be evidence of the bivalve Fluminea corbiola present in most samples. This bivalve is an invasive species in the area, originally from Asia.

  4. Potential for increased mercury accumulation in the estuary food web

    Directory of Open Access Journals (Sweden)

    Samuel N. Luoma

    2003-10-01

    Full Text Available Present concentrations of mercury in large portions of San Francisco Bay (Bay, the Sacramento-San Joaquin Delta (Delta, and the Sacramento and San Joaquin rivers are high enough to warrant concern for the health of humans and wildlife. Large scale tidal wetland restoration is currently under consideration as a means of increasing populations of fish species of concern. Tidal wetland restoration activities may lead to increased concentrations of mercury in the estuarine food web and exacerbate the existing mercury problem. This paper evaluates our present ability to predict the local and regional effects of restoration actions on mercury accumulation in aquatic food webs. A sport fish consumption advisory is in place for the Bay, and an advisory is under consideration for the Delta and lower Sacramento and San Joaquin rivers. Mercury concentrations in eggs of several water bird species from the Bay have exceeded the lowest observed effect level. A variety of mercury sources, largely related to historic mercury and gold mining, is present in the watershed and has created a spatially heterogeneous distribution of mercury in the Bay-Delta Estuary. Mercury exists in the environment in a variety of forms and has a complex biogeochemical cycle. The most hazardous form, methylmercury, is produced at a relatively high rate in wetlands and newly flooded aquatic habitats. It is likely that distinct spatial variation on multiple spatial scales exists in net methylmercury production in Bay-Delta tidal wetlands, including variation within each tidal wetland, among tidal wetlands in the same region, and among tidal wetlands in different regions. Understanding this spatial variation and its underlying causes will allow environmental managers to minimize the negative effects of mercury bioaccumulation as a result of restoration activities. Actions needed to reduce the uncertainty associated with this issue include a long term, multifaceted research effort, long term monitoring on local and regional scales, and careful evaluation of individual restoration projects with regard to potential increase of food web mercury.

  5. Status of the belugas of the St Lawrence estuary, Canada

    Directory of Open Access Journals (Sweden)

    Michael CS Kingsley

    2014-01-01

    Full Text Available A population of belugas (Delphinapterus leucas inhabiting the estuary of the St Lawrence river in Quebec, Canada, was depleted by unregulated hunting, not closed until 1979. Surveys in 1977 showed only a few hundred in the population. Surveys since then have produced increasing estimates of population indices. An estimate of the population, fully corrected for diving animals, was 1,238 (SE 119 in September 1997. The population was estimated to have increased from 1988 through 1997 by 31.4 belugas/yr (SE 13.1. Observations of population age structure, as well as data on age at death obtained from beach-cast carcasses, do not indicate serious problems at the population level, although there are indications that mortality of the oldest animals may be elevated. Few animals appear to live much over 30 years. From examination of beach-cast carcasses, it appears that most deaths are due to old age and disease; hunting is illegal, ship strikes and entrapments in fishing gear are rare, ice entrapments and predation are unknown. Among beach-cast carcasses recovered and necropsied, about 23% of the adults have malignant cancers, while most of the juveniles have pneumonia; other pathological conditions are diverse. No factors are known to be limiting numbers of this population. Habitat quality factors, including persistent contaminants, boat traffic and harassment, may affect the population’s rate of increase, but these effects have not been quantitatively evaluated. Comprehensive legislation exists with powers to protect the population and the environment of which it is a component, but application and enforcement of the laws is not without problems.

  6. Turbulent nitrate fluxes in the Lower St. Lawrence Estuary, Canada

    Science.gov (United States)

    Cyr, Frédéric; Bourgault, Daniel; Galbraith, Peter S.; Gosselin, Michel

    2015-03-01

    Turbulent vertical nitrate fluxes were calculated using new turbulent microstructure observations in the Lower St. Lawrence Estuary (LSLE), Canada. Two stations were compared: the head of the Laurentian Channel (HLC), where intense mixing occurs on the shallow sill that marks the upstream limit of the LSLE, and another station located about 100 km downstream (St. 23), more representative of the LSLE mean mixing conditions. Mean turbulent diffusivities and nitrate fluxes at the base of the surface layer for both stations were, respectively (with 95% confidence intervals): K¯HLC = 8.6>(3.2,19>) × 10-3 m2 s-1,K¯23 = 4.4>(2.3,7.6>) × 10-5 m2 s-1,F¯HLC = 95>(18,300>) mmol m-2 d-1, and F¯23 = 0.21>(0.12,0.33>) mmol m-2 d-1. Observations suggest that the interplay between large isopleth heaving near the sill and strong turbulence is the key mechanism to sustain such high turbulent nitrate fluxes at the HLC (two to three orders of magnitude higher than those at Station 23). Calculations also suggest that nitrate fluxes at the HLC alone can sustain primary production rates of 3.4>(0.6,11>) g C m-2 mo-1 over the whole LSLE, approximately enough to account for a large part of the phytoplankton bloom and for most of the postbloom production. Surfacing nitrates are also believed to be consumed within the LSLE, not leaving much to be exported to the rest of the Gulf of St. Lawrence. This article was corrected on 13 APR 2015. See the end of the full text for details.

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

    Science.gov (United States)

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

    2013-12-01

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

  8. Natural radionuclides (210)Po and (210)Pb in the Delaware and Chesapeake Estuaries: modeling scavenging rates and residence times.

    Science.gov (United States)

    Marsan, D; Rigaud, S; Church, T

    2014-12-01

    During the spring and summer months of 2012, (210)Po and (210)Pb activity were measured in the dissolved and particulate phases from the Delaware and upper Chesapeake estuaries. The upper Delaware estuary, near the freshwater end member, was characterized by high-suspended matter concentrations that scavenged dissolved (210)Po and (210)Pb. Box models were applied using mass balance calculations to assess the nuclides residence times in each estuary. Only 60% of the dissolved (210)Po and 55% of the dissolved (210)Pb from the Delaware estuary were exported to coastal waters. A large fraction of soluble (210)Po and (210)Pb within the estuary was either reversibly adsorbed onto suspended particles, trapped in sediment accumulation zones (such as intertidal marshes), bioaccumulated into phytoplankton and discharged to the coastal ocean. The upper Chesapeake estuary was largely characterized by sub-oxic bottom waters that contained higher concentrations of dissolved (210)Po and (210)Pb, hypothesized to be subjected to redox cycling of manganese. The Delaware and Chesapeake estuary mean residence times for (210)Po differed significantly at 86 ± 7 and 126 ± 10 days respectively, while they were similar for (210)Pb (67 ± 6-55 ± 5 days). The difference in residence times corresponds to the greater extent of biogeochemical scavenging and regeneration processes within the upper Chesapeake. PMID:25239647

  9. Role of intertidal wetlands for tidal and storm tide attenuation along a confined estuary: a model study

    Science.gov (United States)

    Smolders, S.; Plancke, Y.; Ides, S.; Meire, P.; Temmerman, S.

    2015-05-01

    Coastal lowlands and estuaries are subjected to increasing flood risks during storm surges due to global and regional changes. Tidal wetlands are increasingly valued as effective natural buffers for storm surges by dissipating wave energy and providing flood water storage. While previous studies focused on flood wave attenuation within and behind wetlands, this study focuses on the effects of estuarine wetland properties on the attenuation of a storm tide that propagates along the length of an estuary. Wetland properties including elevation, surface area, and location within the estuary were investigated using a numerical model of the Scheldt estuary (Belgium, SW Netherlands). For a spring tide lower wetland elevations result in more attenuation of high water levels along the estuary, while for a higher storm tide higher elevations provide more attenuation compared to lower wetland elevations. For spring and storm tide a arger wetland surface area results in a better attenuation along the estuary up to a threshold wetland size for which larger wetlands do not further contribute to more attenuation. Finally a wetland of the same size and elevation, but located more upstream in the estuary, can store a larger proportion of the local flood volume and therefore has a larger attenuating effect on upstream high water levels. With this paper we aim to contribute towards a better understanding and wider implementation of ecosystem-based adaptation to increasing estuarine flood risks associated with storms.

  10. Modelling of estuarine response to sea-level rise during the Holocene: Application to the Guadiana Estuary-SW Iberia

    Science.gov (United States)

    Sampath, D. M. R.; Boski, T.; Loureiro, C.; Sousa, C.

    2015-03-01

    This paper focuses on simulations of the morphological evolution of an estuary during sedimentary infilling that accompanied Holocene sea-level rise. The simulations were conducted using the Estuarine Sedimentation Model, which uses a behaviour-oriented approach, supported by the chronostratigraphy of the estuary's sedimentary sequence. Behaviour curves were computed to represent the relationship between the estuarine channel depth below maximum high tide and the net accretion at a given location relative to the average sedimentation rate of the estuary during the Holocene. The model was validated by comparing the observed present-day bathymetry of the Guadiana River Estuary, southeastern Portugal, with the corresponding simulated bathymetries for nine control sections across the estuary. The best fit between simulated and actual sediment surface elevations was obtained along the cross-sections in the sheltered, low-energy environments of the estuary. The accuracy of the sedimentary stratigraphy of the best-fit model was further established using 16 radiocarbon ages obtained from five boreholes in the estuary. The present approach is particularly suitable for simulating long-term morphological evolution in sheltered estuarine environments where tidally driven vertical aggradation dominates at centennial to millennium timescales. However, the accuracy of simulated sediment surface elevations and consequently the robustness of behaviour-type models based on Geographical Information System platforms can be enhanced by incorporating (i) the impacts of nearshore hydrodynamic processes and episodic flood events in highly energetic channels, and (ii) the impacts of cross-currents in meandering channel sections.

  11. Influences of Environmental Factors on Fish Assemblage in the Tropical Estuary of South West Coast of India, A Case Study of Kodungallur-Azhikode Estuary

    Directory of Open Access Journals (Sweden)

    O.K. Sreedevi

    2013-01-01

    Full Text Available A proper monitoring of aquatic environment is crucial to appropriate management of the fisheries that rely on harvests from the environment and attempts of present study have been made to demonstrate links with environmental variability and fish abundance in the Kodungallur-Azhikode estuary (KAE. Annual average fish production in the estuary was declined considerably to 908.6 tons during 2009-2010, where 2747 tons was reported. Sixty three species of fin fishes, six species of penaeid shrimps, one species of Palaemonid prawns, two species of crabs, four species of bivalves and two species of edible oysters were observed in this study. Present study revealed that, Salinity is consistently the most important parameter explaining variation in assemblage composition and abundance of KAE; the availability of fish for recruitment into an estuary depends primarily upon the distributional range of euryhaline marine and estuarine species. The direct gradient analysis, first CCA axis, which explained most of the variation (45% in the species data, was related to salinity, transparency and pH, and first two CCA axes together explained 72% of the cumulative percent variance of species-environment relationship. The importance of monitoring the estuarine condition in relation to fish assemblage was discussed, with significance on the potential use of estuarine fish assemblages and their monitoring and surveillance in management programs.

  12. Propagation of tides in the Cochin estuarine system, southwest coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Srinivas, K.; Revichandran, C.; Maheswaran, P.A.; Asharaf, T.T.M.; Murukesh, N.

    2003-01-01

    Analysis of hourly data on sea level collected at four stations in the Cochin estuarine system, Kerala, India has been made to understand the tidal and non-tidal sea level variations inside the estuary, for spring and neap phases during March 2000...

  13. Holocene reef accretion: southwest Molokai, Hawaii, U.S.A.

    Science.gov (United States)

    Engels, Mary S.; Fletcher, Charles H., III; Field, Michael E.; Storlazzi, Curt D.; Grossman, Eric E.; Rooney, John J.B.; Conger, Christopher L.; Glenn, Craig

    2004-01-01

    Two reef systems off south Molokai, Hale O Lono and Hikauhi (separated by only 10 km), show strong and fundamental differences in modern ecosystem structure and Holocene accretion history that reflect the influence of wave-induced near-bed shear stresses on reef development in Hawaii. Both sites are exposed to similar impacts from south, Kona, and trade-wind swell. However, the Hale O Lono site is exposed to north swell and the Hikuahi site is not. As a result, the reef at Hale O Lono records no late Holocene net accretion while the reef at Hikauhi records consistent and robust accretion over late Holocene time. Analysis and dating of 24 cores from Hale O Lono and Hikauhi reveal the presence of five major lithofacies that reflect paleo-environmental conditions. In order of decreasing depositional energy they are: (1) coral-algal bindstone; (2) mixed skeletal rudstone; (3) massive coral framestone; (4) unconsolidated floatstone; and (5) branching coral framestone-bafflestone. At Hale O Lono, 10 cores document a backstepping reef ranging from ? 8,100 cal yr BP (offshore) to ? 4,800 cal yr BP (nearshore). A depauperate community of modern coral diminishes shoreward and seaward of ? 15 m depth due to wave energy, disrupted recruitment activities, and physical abrasion. Evidence suggests a change from conditions conducive to accretion during the early Holocene to conditions detrimental to accretion in the late Holocene. Reef structure at Hikauhi, reconstructed from 14 cores, reveals a thick, rapidly accreting and young reef (maximum age ? 900 cal yr BP). Living coral cover on this reef increases seaward with distance from the reef crest but terminates at a depth of ? 20 m where the reef ends in a large sand field. The primary limitation on vertical reef growth is accommodation space under wave base, not recruitment activities or energy conditions. Interpretations of cored lithofacies suggest that modern reef growth on the southwest corner of Molokai, and by extension across Hawaii in general, is controlled by wave-induced near-bed shear stress related to refracted North Pacific swell. Holocene accretion patterns here also reflect the long-term influence of wave-induced near-bed shear stress from north swell during late Holocene time. This finding is consistent with other studies (e.g., Grigg 1998; Cabioch et al. 1999) that reflect the dominance of swell energy and sea level in controlling modern and late Holocene accretion elsewhere in Hawaii and across the Pacific and Indian oceans. Notably, however, this result is refined and clarified for Hawaii in the hypothesis of Rooney et al. (2003) stating that enhancement of the El Niño Southern Oscillation beginning approximately 5000 years ago led to increased north swell energy and signaled the end to net accretion along exposed coastlines in Hawaii. The exposure of Hale O Lono to north swell and the age of sea floor there (ca. 4,800 cal yr BP), coupled with the lack of north swell incidence at Hikauhi and the continuous accretion that has occurred there over the last millennium, strongly supports the ENSO reef hypothesis as outlined by Rooney et al. (2003). Other factors controlling Holocene reef accretion at the study site are relative sea-level position and rate of rise, and wave sheltering by Laau Point. Habitat suitable for reef accretion on the southwest shore of Molokai has shrunk throughout the Holocene.

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

    Science.gov (United States)

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

    2012-12-01

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

  15. USING IMAGE PROCESSING METHODS WITH RASTER EDITING TOOLS FOR MAPPING EELGRASS DISTRIBUTIONS IN PACIFIC NORHWEST ESTUARIES

    Science.gov (United States)

    False-color near-infrared (CIR) aerial photography of seven Oregon estuaries was acquired at extreme low tides and digitally orthorectified with a ground pixel resolution of 25 cm to provide data for intertidal vegetation mapping. Exposed, semi-exposed and some submerged eelgras...

  16. Macroalgal accumulation in a Pacific Northwest estuary - evidence of poor eutrophic condition?

    Science.gov (United States)

    A five year study of benthic macroalgal dynamics was conducted in Yaquina estuary, Oregon, yielding 400 surveys of average macroalgal cover and biomass within three intertidal bathymetric zones at six sites covering the range of native eelgrass habitat. Application of a publishe...

  17. Monitoring the Condition of the Estuaries of the United States: The National Coastal Assessment Experience

    Science.gov (United States)

    Coastal waters in the United States include estuaries, bays, sounds, coastal wetlands, coral reefs, intertidal zones, mangrove and kelp forests, seagrass meadows, and coastal ocean and upwelling areas (i.e. deep water rising to surface). These coastal areas encompass a wide diver...

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

    Science.gov (United States)

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

  19. Baseline metals pollution profile of tropical estuaries and coastal waters of the Straits of Malacca

    International Nuclear Information System (INIS)

    Highlights: • Order of metals distribution were as follow: Fe > Al > Se > Cu > As > Zn > Mn > Ni > Ba > Pb > Cd > Cr > Co. • As and Cu levels have exceeded Malaysia Marine Water Quality Criteria and Standard. • Seven principal components of PCA were extracted from estuaries and coastal waters. • Mineral-related parameters are main pollution sources in the waters. -- Abstract: The status report on metal pollution in tropical estuaries and coastal waters is important to understand potential environmental health hazards. Detailed baseline measurements were made on physicochemical parameters (pH, temperature, redox potential, electrical conductivity, salinity, dissolved oxygen, total dissolved solid), major ions (Na, Ca, Mg, K, HCO3, Cl, SO4 and NO3) and metals concentrations (27Al, 75As, 138Ba, 9Be, 111Cd, 59Co, 63Cu, 52Cr, 57Fe, 55Mn, 60Ni, 208Pb, 80Se, 66Zn) at estuaries and coastal waters along the Straits of Malacca. Principal component analysis (PCA) was employed to reveal potential pollution sources. Seven principal components were extracted with relation to pollution contribution from minerals-related parameters, natural and anthropogenic sources. The output from this study will generate a profound understanding on the metal pollution status and pollution risk of the estuaries and coastal system

  20. Tidal asymmetry in the Mandovi and Zuari estuaries, the West Coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Manoj, N.T; Unnikrishnan, A.S.; Sundar, D.

    2009-01-01

    the decay in amplitude due to friction. The rapid increase of the first and second harmonics of M sub(2) and compound tides inside the estuaries shows the nonlinear response of the Mandovi and Zuari estuarine systems to tidal forcing. The M sub(4)/M sub(2...

  1. Comparison of the structure of lower and upper estuary food webs for Yaquina Bay (OR)

    Science.gov (United States)

    Food web models can be used to estimate effects of water quality, habitat distribution or species loss on productivity, carbon flow and ecosystem service production in Pacific NW estuaries. Here we present a comparison of floral and faunal data used to parameterize food web mode...

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

    Science.gov (United States)

    Zhang, Jing

    1995-12-01

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

  3. Limno-tolerant bacteria govern nitrate concentration in Mandovi estuary, India

    Digital Repository Service at National Institute of Oceanography (India)

    Divya, B; Fernandes, S.O.; Sheelu, G.; Nair, S.; LokaBharathi, P.A.; Chandramohan, D.

    2009-01-01

    parameters on a monthly basis at three fixed stations for a year. On an annual basis, the estuary showed an average salinity of 28.2, 17.4, and 12.6 at the mouth, midstream and upstream region. Halo-tolerant retrievable count (HTRC) and limno...

  4. Artificial structures in sediment-dominated estuaries and their possible influences on the ecosystem.

    Science.gov (United States)

    Wetzel, Markus A; Scholle, Jörg; Teschke, Katharina

    2014-08-01

    Artificial substrates are omnipresent today in most estuaries mostly in form of massive rip-rap used for groynes and jetties. In the Weser estuary, Germany, 60% of the shoreline is covered with such artificial substrates while, natural rocky substrate is lacking, as in all Wadden Sea estuaries. This large quantity of artificial substrates may be colonized by a benthic hard-substrate community which differs from the local natural soft-substrate assemblage. In this study we examined species compositions, abundances, biomass, and numbers of species of subtidal benthic communities on groynes and in the natural habitat, the sediment, along the salinity gradient of the Weser estuary. Species composition changed on both substrates significantly with salinity and was also significantly different between the substrates. In a comparison with the sediment, the groynes did not provide any benefit for non-indigenous nor for endangered species in terms of abundance, biomass, and number of species, but represent habitats with higher total abundances and biomass; though some non-indigenous species even occurred exclusively on groynes. In particular, groynes supported filter-feeding organisms which play an important role by linking benthic and pelagic food webs. The dominance of the suspension feeders affects crucial estuarine ecosystem services and may have important implications for the estuarine management by altering the estuarine ecological quality status. Hence, artificial substrates should be considered in future conservation planning and in ecological quality monitoring of the benthic fauna according to the European Water Framework Directive. PMID:24816192

  5. Diurnal variations in bacterial and viral production in Cochin estuary, India

    Digital Repository Service at National Institute of Oceanography (India)

    Parvathi, A.; Jasna, V.; Haridevi, C.K.; Jina, S.; Greeshma, M.; Breezy, J.; Nair, M.

    2013-01-01

    of bacterial production (BP) and viral production (VP) with respect to primary production over a diurnal period in Cochin estuary. Time series measurements were made every 2 h for 12 h (6 a.m.–6 p.m.) during periods of low and high salinities. The light...

  6. Composition and Diversity of Phytoplankton from Mangrove Estuaries in Sarawak, Malaysia

    Directory of Open Access Journals (Sweden)

    A.S.M. Saifullah

    2014-01-01

    Full Text Available The composition and diversity of phytoplankton were studied along with physico-chemical parameters of water of two mangrove-dominated estuaries i.e., Kuala Sibuti (KS and Kuala Nyalau (KN, Sarawak, Malaysia. A total of 46 species of phytoplankton with the mean density of 147000 cells L-1 were recorded from KS estuary i.e., 3 species of Cyanophyceae; 22 species of Bacillariophyceae; 20 species of Dinophyceae and 1 species of Chlorophyceae. The recorded mean density of phytoplankton was 113000 cells L-1 with 33 species from 19 genera from KN estuary, in which 19 species were from Bacillariophyceae; 12 species were from Dinophyceae; 1 species was from Cyanophyceae and 1 species was from Chlorophyceae. In both the estuaries, the species composition was found to be in an order of Diatom>Dinoflagellate>Cyanophyceae>Chlorophyceae. Canonical Correspondence Analysis (CCA revealed that the abundance of Bacillariophyceae and Dinoflagellates was influenced by salinity and conductivity along with ammonium and phosphate while the abundance of Chlorophyceae was influenced by temperature, TDS, DO and pH in KS. The influence of salinity and conductivity along with PO4 and NH4 on the abundance of Bacillariophyceae, Dinoflagellates and Chlorophyceae were observed in KN.

  7. Analytical approach for predicting fresh water discharge in an estuary based on tidal water level observations

    Directory of Open Access Journals (Sweden)

    H. Cai

    2014-06-01

    Full Text Available As the tidal wave propagates into an estuary, the tidally averaged water level tends to rise in landward direction due to the density difference between saline and fresh water and the asymmetry of the friction. The effect of friction on the residual slope is even more remarkable when accounting for fresh water discharge. In this study, we investigate the influence of river discharge on tidal wave propagation in the Yangtze estuary with specific attention to residual water level slope. This is done by using a one-dimensional analytical model for tidal hydrodynamics accounting for the residual water level. We demonstrate the importance of the residual slope on tidal dynamics and use it to improve the prediction of the tidal propagation in estuaries (i.e., tidal damping, velocity amplitude, wave celerity and phase lag, especially when the influence of river discharge is significant. Finally, we develop a new inverse analytical approach for estimating fresh water discharge on the basis of tidal water level observations along the estuary, which can be used as a tool to obtain information on the river discharge that is otherwise difficult to measure in the tidal region.

  8. Seasonal and spatial distributions of tributyltin in surface sediment of the Tolka Estuary, Dublin, Ireland

    International Nuclear Information System (INIS)

    Aquatic pollution by tributyltin (TBT) is of concern because of its high toxicity to marine life. TBT loadings of estuarine sediments may remain elevated because of long flushing times in estuaries due to their enclosed physicality. The Tolka Estuary, Co. Dublin, Ireland, is a typical Irish urban estuary. It has a significant pollution loading. The results of 12 months' analysis of TBT spatial and temporal distributions in this estuary are presented in this paper. Data from a total of 10 sample points are presented. The concentrations of TBT in the sediment were analysed using differential pulse polarography. Significant seasonal and spatial trends in TBT distribution were observed over the 12-month period. TBT concentrations ranged from 0.1 ppb in winter to 8.6 ppb in summer with a 1.5 ppb average. Organic matter (OM) concentrations of sediment exhibited similar seasonal trends and a positive correlation between OM and TBT distributions was observed. - TBT concentrations varied with seasons and correlated well with organic matter

  9. Seasonal and spatial distribution of metals in surface sediment of an urban estuary

    International Nuclear Information System (INIS)

    Aquatic pollution by metals is of concern because of various toxic effects to marine life. The Tolka Estuary, Co. Dublin, Ireland, is a typical Irish urban estuary. It has a significant metal loading originating from the urban environment. Results of a 25 month analysis of cadmium, copper, lead and zinc spatial and temporal distribution over 10 sample locations in this estuary are presented in this paper. Metal concentrations were analysed using differential pulse polarography. Significant seasonal and spatial trends in metal distribution were observed over the 25 months. Sediment metal concentrations gradually increased (30-120%) in spring to a maximum at the end of summer which was followed by a decrease in winter months (30-60%). Sediment organic matter (OM) concentrations exhibited similar seasonal trends and a positive correlation between OM and metal distributions was observed, implying OM had an influence on metal distributions over time. - Assessment and correlation of the seasonal and spatial distribution of metals and organic matter in surface sediment of an urban estuary

  10. Seasonal and spatial distributions of tributyltin in surface sediment of the Tolka Estuary, Dublin, Ireland

    Energy Technology Data Exchange (ETDEWEB)

    Buggy, Conor J. [Department of Biotechnology, Dublin City University, Glasnevin, Dublin (Ireland); Tobin, John M. [Department of Biotechnology, Dublin City University, Glasnevin, Dublin (Ireland)]. E-mail: john.tobin@dcu.ie

    2006-09-15

    Aquatic pollution by tributyltin (TBT) is of concern because of its high toxicity to marine life. TBT loadings of estuarine sediments may remain elevated because of long flushing times in estuaries due to their enclosed physicality. The Tolka Estuary, Co. Dublin, Ireland, is a typical Irish urban estuary. It has a significant pollution loading. The results of 12 months' analysis of TBT spatial and temporal distributions in this estuary are presented in this paper. Data from a total of 10 sample points are presented. The concentrations of TBT in the sediment were analysed using differential pulse polarography. Significant seasonal and spatial trends in TBT distribution were observed over the 12-month period. TBT concentrations ranged from 0.1 ppb in winter to 8.6 ppb in summer with a 1.5 ppb average. Organic matter (OM) concentrations of sediment exhibited similar seasonal trends and a positive correlation between OM and TBT distributions was observed. - TBT concentrations varied with seasons and correlated well with organic matter.

  11. Seasonal and spatial distribution of metals in surface sediment of an urban estuary

    Energy Technology Data Exchange (ETDEWEB)

    Buggy, Conor J. [School of Biotechnology, Dublin City University, Glasnevin, Dublin 9 (Ireland); Tobin, John M. [School of Biotechnology, Dublin City University, Glasnevin, Dublin 9 (Ireland)], E-mail: john.tobin@dcu.ie

    2008-09-15

    Aquatic pollution by metals is of concern because of various toxic effects to marine life. The Tolka Estuary, Co. Dublin, Ireland, is a typical Irish urban estuary. It has a significant metal loading originating from the urban environment. Results of a 25 month analysis of cadmium, copper, lead and zinc spatial and temporal distribution over 10 sample locations in this estuary are presented in this paper. Metal concentrations were analysed using differential pulse polarography. Significant seasonal and spatial trends in metal distribution were observed over the 25 months. Sediment metal concentrations gradually increased (30-120%) in spring to a maximum at the end of summer which was followed by a decrease in winter months (30-60%). Sediment organic matter (OM) concentrations exhibited similar seasonal trends and a positive correlation between OM and metal distributions was observed, implying OM had an influence on metal distributions over time. - Assessment and correlation of the seasonal and spatial distribution of metals and organic matter in surface sediment of an urban estuary.

  12. Utilization of organic matter by invertebrates along an estuarine gradient in an intermittently open estuary

    Science.gov (United States)

    Lautenschlager, Agnes D.; Matthews, Ty G.; Quinn, Gerry P.

    2014-08-01

    In intermittently open estuaries, the sources of organic matter sustaining benthic invertebrates are likely to vary seasonally, particularly between periods of connection and disconnection with the ocean and higher and lower freshwater flows. This study investigated the contribution of allochthonous and autochthonous primary production to the diet of representative invertebrate species using stable isotope analysis (SIA) during the austral summer and winter (2008, 2009) in an intermittently open estuary on the south-eastern coast of Australia. As the study was conducted towards the end of a prolonged period of drought, a reduced influence of freshwater/terrestrial organic matter was expected. Sampling was conducted along an estuarine gradient, including upper, middle and lower reaches and showed that the majority of assimilated organic matter was derived from autochthonous estuarine food sources. Additionally, there was an input of allochthonous organic matter, which varied along the length of the estuary, indicated by distinct longitudinal trends in carbon and nitrogen stable isotope signatures along the estuarine gradient. Marine seaweed contributed to invertebrate diets in the lower reaches of the estuary, while freshwater/terrestrial organic matter had increased influence in the upper reaches. Suspension-feeding invertebrates derived large parts of their diet from freshwater/terrestrial material, despite flows being greatly reduced in comparison with non-drought years.

  13. Physiological status and intersex in the endobenthic bivalve Scrobicularia plana from thirteen estuaries in northwest France

    International Nuclear Information System (INIS)

    The bivalve Scrobicularia plana, an important species for the structure and functioning of estuarine and coastal mudflats, was studied in thirteen sites from NW France differing by their degree of contamination to document the presence of reproduction impairments (intersex, sex ratio, gonadosomatic indices) in relation to the condition revealed by using hepatosomatic and condition indices. In agreement with recent studies in other European estuaries, intersex was revealed in all the studied estuaries, including sites the chemical and ecological status of which is considered “good” according to the criteria of the European Water Framework Directive. The presence of endocrine disrupting chemicals (EDCs) could result in such disturbances. Our results re-inforce the concern linked to the subtle effects of EDCs, which are active at very low doses, often in the absence of any major sign of toxicity. However at this stage, no clear link may be established between intersex and population effects. - Highlights: ? Clams were collected from 13 estuaries differing by their degree of contamination. ? Gonadosomatic, hepatosomatic and condition indices were determined. ? Reproduction impairments (intersex, biased sex ratio, asynchronism) were shown. ? Intersex shown even at sites with good ecological status (Water Framework Directive). ? No clear links between intersex and populational effects. - Intersex in clams from estuaries, the chemical/ecological status of whichl/ecological status of which was considered as good under the EC Water Framework Directive.

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

    Energy Technology Data Exchange (ETDEWEB)

    Roegner, G. Curtis; Diefenderfer, Heida L.; Borde, Amy B.; Thom, Ronald M.; Dawley, Earl M.; Whiting, Allan H.; Zimmerman, Shon A.; Johnson, Gary E.

    2008-04-25

    Protocols for monitoring salmon habitat restoration projects are essential for the U.S. Army Corps of Engineers' environmental efforts in the Columbia River estuary. This manual provides state-of-the science data collection and analysis methods for landscape features, water quality, and fish species composition, among others.

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

    Science.gov (United States)

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Gary E.; Diefenderfer, Heida L.; Thom, Ronald M.; Roegner, G. Curtis; Ebberts, Blaine D.; Skalski, John R.; Borde, Amy B.; Dawley, Earl; Coleman, Andre M.; Woodruff, Dana L.; Breithaupt, Stephen A.; Cameron, April; Corbett, C.; Donley, Erin E.; Jay, D. A.; Ke, Yinghai; Leffler, K.; McNeil, C.; Studebaker, Cindy; Tagestad, Jerry D.

    2012-05-01

    This is the seventh and final annual report of a project (2004–2010) addressing evaluation of the cumulative effects of habitat restoration actions in the 235-km-long lower Columbia River and estuary. The project, called the Cumulative Effects (CE) study, was conducted for the U.S. Army Corps of Engineers Portland District by a collaboration of research agencies led by the Pacific Northwest National Laboratory. We achieved the primary goal of the CE study to develop a methodology to evaluate the cumulative effects of habitat actions in the Columbia Estuary Ecosystem Restoration Program. We delivered 1) standard monitoring protocols and methods to prioritize monitoring activities; 2) the theoretical and empirical basis for a CE methodology using levels-of-evidence; 3) evaluations of cumulative effects using ecological relationships, geo-referenced data, hydrodynamic modeling, and meta-analyses; and 4) an adaptive management process to coordinate and coalesce restoration efforts in the LCRE. A solid foundation has been laid for future comprehensive evaluations of progress made by the Columbia Estuary Ecosystem Restoration Program to understand, conserve, and restore ecosystems in the lower Columbia River and estuary.

  17. Numerical modelling of tidal circulation and studies on salinity distribution in Mandovi and Zuari estuaries

    Digital Repository Service at National Institute of Oceanography (India)

    Manoj, N.T.

    2008-01-01

    2D model and an area averaged 1D model was used to simulate tides and salinity distribution in the Mandovi and Zuari estuaries. The vertically averaged 2D model was used for the downstream regions of these channels. An area averaged 1D model...

  18. DOCUMENTING THE INTERTIDAL COMPONENT OF EELGRASS DISTRIBUTIONS IN PACIFIC NORTHWEST ESTUARIES USING COLOR INFRARED AERIAL PHOTOGRAPHY

    Science.gov (United States)

    The objective of this study was to develop and test a rapid, cost-effective method of mapping the intertidal (and surface-visible subtidal) distribution of eelgrass (Zostera marina L.) meadows and patches in the turbid coastal estuaries of the Pacific Northwest (PNW). Initial co...

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

    Science.gov (United States)

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

    2014-12-01

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

  20. Numerical modelling of fish eggs dispersion at the Patos Lagoon estuary — Brazil

    Science.gov (United States)

    Martins, I. M.; Dias, J. M.; Fernandes, E. H.; Muelbert, J. H.

    2007-12-01

    The Patos Lagoon estuary is the most important nursery ground for commercially relevant species of fish and crustaceans in the South of Brazil, maintaining fisheries that sustain 3500 fisher families throughout the Rio Grande do Sul State coastline. Around 80% of the interior estuarine area is very shallow (recruitment of fish eggs and larvae to the inner parts of the Patos Lagoon estuary is directly related to the circulation pattern in the area, which is controlled by local and non-local wind effects and freshwater discharge. The objective of this study is to investigate the processes controlling the transport of estuarine dependent fish eggs between the Atlantic Ocean and the Patos Lagoon estuary. An integrated numerical system based on a bi-dimensional hydrodynamic model and a Lagrangean transport model of passive particles is applied to a selection of scenarios representing the passage of weather fronts over the area. At this stage, fish eggs are represented as buoyant passive particles. Modelling results are compared against field data for the period under investigation (September/October 1999) and historical records. Short term results are analysed in terms of the meteorological conditions (wind direction, intensity and duration) controlling the transport of eggs to the inner parts of the estuary and the extension of their excursion. This experiment is the first attempt to couple biological and physical information to study fish eggs transport, and to enhance the current knowledge about recruitment of important fisheries resources in southern Brazil.