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Sample records for gironde estuary southwest

  1. Impact of climate change on Gironde estuary

    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)

  2. The response of land markets to flood protection and flood experience: a hedonic price modeling on the Gironde estuary (France)

    Dachary Bernard, J.; Rambonilaza, T.; Lemarié Boutry, M.

    2014-01-01

    We develop a hedonic price model on the Gironde estuary (south of France) in order to test the impact of vulnerability to flooding on land prices. The original contribution of our analysis relies on distinguishing the respective impact of two non-structural measures on land prices - the preventive strategy consisting in a flood hazard zoning and the curative response to flood events consisting in orders for natural disaster to initiate financial compensation. This analysis is conducted on thr...

  3. Mobility of trace metals associated with urban particles exposed to natural waters of various salinities from the Gironde Estuary, France

    Schaefer, Joerg; Blanc, Gerard [Bordeaux Univ., Talence (France). UMR 5805 EPOC; Norra, Stefan [Karlsruhe Univ. (Germany). Inst. of Mineralogy and Geochemistry; Klein, Daniel [Bordeaux Univ., Talence (France). UMR 5805 EPOC; Karlsruhe Univ. (Germany). Inst. of Mineralogy and Geochemistry

    2009-08-15

    Background, aim and scope: Urban systems are hot spots of environmental pollution caused by manifold anthropogenic activities generating traffic-related, industrial and domestic emissions. Besides air, soil and groundwater pollution, pollution of surface water systems is of major concern because they are often (ab)used to export waste of various consistence out of urban areas and become contaminated on varying scales. The Gironde Estuary (southwest France) is affected by various anthropogenic contaminations derived from historic polymetallic pollution mainly due to former mining and ore-treatment and, additionally, from agriculture and urban areas. Although detailed knowledge is available on the impact of mining and anthropogenic activities on the water quality of the Gironde Estuary, almost nothing is known on the urban impact, even though the Garonne Branch which is one tributary of the Gironde system crosses the large urban agglomeration of Bordeaux. The present work links urban geochemistry and estuary research and aims at evaluating the mobility of potentially toxic trace elements (Cd, Cu, Zn, V, Co, Mo, Pb) associated with urban particles under estuarine conditions owing to the particles' role as potential vectors transporting urban pollutants into the estuary. For this, environmentally available fractions of trace elements in representative urban particles (urban dust, road sediment, riverbank sediment, construction materials) from the city of Bordeaux were extracted by natural estuarine waters of varying salinities and compared to commonly applied HNO{sub 3} extractions. Materials and methods: For the assessment of the urban particles' contribution to the pollution of the Gironde/Garonne system, various particle types were sampled in Bordeaux: road sediments, urban bulk deposition, construction materials (concrete, asphalt, tile and gravel) and flood sediments. Potentially environmental available fractions of Cd, Cu, Zn, V, Co, Mo and Pb were

  4. Sedimentary facies and paleoenvironmental interpretation of a Holocene marsh in the Gironde Estuary in France

    WANG Jianhua; MASSE Laurent; TASTET Jean-Pierre

    2006-01-01

    The Monards Marsh is located on the northeastern bank of the Gironde Estuary in France. Lithological, sedimentological and micropalaeontological investigations were made on four cores to determine the evolution of Holocene sedimentary environments and processes in this area over the last 6 000 a. Three main lithological facies are distinguished from bottom to top: (1) grey laminated silty-sandy clay; (2) homogeneous dark grey silty clay; and (3) compact silty clay. About 26 benthic foraminifera species are identified and divided into six groups according to their ecological characteristics. In association with lithology, sedimentary structures and grainulometry, the distribution of foraminifera group is used to define external slikke, internal slikke, external schorre, internal schorre, and continental marsh facies. Combined with 14C(AMS) dating, these data indicate four successive paleoenvironments in the Monards Marsh: (1) Holocene transgression resulted in the development of a basal schorre facies overlying fluvial deposits that transformed to slikke facies sedimentation; the transgression maximum occurred around 5 600 to 5 400 a BP and was inferred to be associated with the last phase of the rapid Holocene sea-level rise; (2) post-trangressive maximum sedimentation resulted in a regressive sequence of deposits prograding towards the estuary, corresponding to the stabilisation of sea level after 5 400 a BP; (3) a slight positive tendency in the sea level around 2 800 a BP recorded in the central part of the marsh; and (4) the wetland to a continental marsh environment. The sequential pattern for the evolution of wetlands in this estuarine area during the Holocene is fluvial facies-blackish schorre facies-slikke facies-blackish schorre facies-continental marsh facies. Characteristics of sedimentary facies distribution and evolution reveal that the development of Holocene salt marsh in this area was controlled by the sea-level change and tidal range. The

  5. La restauration de l'esturgeon européen (Acipenser sturio) et les extractions de granulats dans la Gironde

    Lepage, M.; Rochard, E.; CASTELNAUD G.

    1998-01-01

    The Gironde estuary in the south-west of France is the last estuary where all diadromous fish from western europe still migrate. In addition, the Gironde-Garonne-Dordogne basin is the last know system where the reproduction of the european sturgeon take place. The european sturgeon is an endangered species which is listed under the Threatened species Red Book of France and other international conventions for the conservation of the nature. It is also fully protected in France since 1982 by a ...

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

    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)

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

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

    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

  9. Geochemical survey and metal bioaccumulation of three bivalve species (Crassostrea gigas, Cerastoderma edule and Ruditapes philippinarum) in the Nord Medoc salt marshes (Gironde estuary, France)

    A 15-month experiment combining a geochemical survey of Cd, Cu, Zn and Hg with a bioaccumulation study for three filter-feeding bivalve species (oysters, Crassostrea gigas; cockles, Cerastoderma edule; and clams, Ruditapes philippinarum) was conducted in a breeding basin of the Nord Medoc salt marshes connected to the Gironde estuary, which is affected by historic polymetallic pollution. Regular manual surface measurements of temperature, salinity, pH and dissolved O2 concentration and hourly multiprobe in situ measurements throughout several periods for 6-8 weeks were performed. The geochemical behavior of metals in water, suspended particulate matter and sediment and their ecotoxicological impact on the three bivalve species were evaluated by in situ exposure of juvenile oysters (water column) and adult cockles and clams (sediment surface). The physico-chemical parameters reflected seasonal variations and basin management. A distinct daily periodicity (except salinity) indicated intense photosynthesis and respiration. In summer, low dissolved O2 saturations (∼40-50%) occurred in the early morning at 30 cm above the sediment, whereas in depressions, the water column near the sediment surface was suboxic. Cadmium, Zn and Cu concentrations in suspended particulate matter exceeded typical estuarine values and were much higher than the homogeneously distributed concentrations in different depth ranges of the basin sediment. Particles collected in sediment traps showed intermediate metal concentrations close to sediment values. These results suggest trace metal recycling due to reductive dissolution under suboxic conditions at the sediment surface resulting in trace metal release to the water column and adsorption onto suspended particles. Dissolved Cd, Zn and Hg concentrations (e.g. 13-136 ng l-1; 0.3-25.1 μg l-1 and 0.5-2.0 ng l-1, respectively) in the basin corresponded to the concentration range typically observed in the Gironde estuary, except for some maximum

  10. Fitting a predator prey model to zooplankton time-series data in the Gironde estuary (France): Ecological significance of the parameters

    David, Valérie; Chardy, Pierre; Sautour, Benoît

    2006-05-01

    The relationships between the seasonal fluctuations of the copepod Eurytemora affinis and the mysid Neomysis integer were studied from observed data and experimental results, using a predator-prey model in the oligo-mesohaline area of the Gironde estuary. Mean seasonal fluctuations of abundances were derived from long term data series collected from 1978 to 2003 for both species. In situ predator-prey experiments over a seasonal cycle were used to estimate the seasonal variation of the consumption rate of N. integer on E. affinis and to verify the order of magnitude of the biological parameters given by the model. Predator-prey experiments revealed a high seasonal variation in maximum consumption rates with a mean of 56 ± 9 ind. pred -1 d -1. Maximum consumption rates were always higher for adults than for juveniles of Neomysis integer. Recorded selectivities were higher on nauplii than on copepodids + adults of Eurytemora affinis, both for the juveniles and the adults of N. integer. Neomysis integer mainly fed on meroplanktonic larvae, when they were available in higher abundances, than E. affinis in their environment. Spring increases of abundance for Eurytemora affinis copepodids + adults seemed to be mainly controlled by temperature whereas its decreasing abundance in summer was more related to Neomysis integer predation, suggesting that summer fluctuations of E. affinis abundance are probably controlled by mysid predation at summer times. Using a Lotka-Volterra predator-prey model, the seasonal peak of abundance of the mysid N. integer was well reproduced considering a predation on copepodids + adults of E. affinis, and suggested a dependence between mysid and copepod seasonal variations. However, the seasonal peak amplitude could not be explained solely by a predation on copepodids + adults or on nauplii of the copepod. Thus, N. integer is probably dependent on the seasonal fluctuations of the copepod's abundance, complementing its diet with macrophytal

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

    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

  12. The particulate 7Be/210Pbxs and 234Th/210Pbxs activity ratios as tracers for tidal-to-seasonal particle dynamics in the Gironde estuary (France): implications for the budget of particle-associated contaminants.

    Saari, Hanna-Kaïsa; Schmidt, Sabine; Castaing, Patrice; Blanc, Gérard; Sautour, Benoît; Masson, Olivier; Cochran, J Kirk

    2010-09-15

    The short-lived natural radionuclides (7)Be (T(1/2)=53 days), (234)Th(xs) (T(1/2)=24.1 days) and (210)Pb(xs) (T(1/2)=22.3 years), i.e. (234)Th and (210)Pb in excesses of that supported within particles by the decay of their parent isotopes, were analysed in suspended particulate matter (SPM) to study the particle dynamics in the Gironde fluvial estuarine system (France), strongly impacted by heavy metal pollution. From surveys of this land-ocean interface in 2006 and 2007, we established a times series of these radioisotopes and of their activity ratios ((7)Be/(210)Pb(xs) and (234)Th/(210)Pb(xs) ARs) in particles sampled under different hydrological conditions. The particulate (7)Be/(210)Pb(xs) AR varies along the fluvial estuarine system mainly due to variations in (7)Be activities, controlled by riverine, oceanic and atmospheric inputs and by resuspension of old (7)Be-deficient sediments. These processes vary with river discharge, tidal cycle and season. Therefore, seasonal particle transport processes can be described using variations of the SPM (7)Be/(210)Pb(xs) ARs. During high river discharge, the SPM (7)Be/(210)Pb(x) ARs decrease from river to the ocean. The turbidity maximum zone (TMZ) is dispersed and the particles, and the associated contaminants, are rapidly transported from river to coastal waters, without significant retention within the TMZ. During low river discharge, the TMZ intrudes into the fluvial estuary, and the lowest (7)Be/(210)Pb(x) ARs are observed there due to resuspension of (7)Be-deficient sediments. Away from the TMZ, from the middle to lower estuary, SPM (7)Be/(210)Pb(x) ARs increase, indicating that the particles have been recently tagged with (7)Be. We explain this trend as being caused by marine input of dissolved radionuclides, as traced by SPM (234)Th/(210)Pb(xs) ARs, followed by scavenging in the estuary. This result indicates that particle transport models based on (7)Be and trace-metal budgets must consider oceanic dissolved

  13. The particulate 7Be/210Pbxs and 234Th/210Pbxs activity ratios as tracers for tidal-to-seasonal particle dynamics in the Gironde estuary (France): Implications for the budget of particle-associated contaminants

    The short-lived natural radionuclides 7Be (T1/2 = 53 days), 234Thxs (T1/2 = 24.1 days) and 210Pbxs (T1/2 = 22.3 years), i.e. 234Th and 210Pb in excesses of that supported within particles by the decay of their parent isotopes, were analysed in suspended particulate matter (SPM) to study the particle dynamics in the Gironde fluvial estuarine system (France), strongly impacted by heavy metal pollution. From surveys of this land-ocean interface in 2006 and 2007, we established a times series of these radioisotopes and of their activity ratios (7Be/210Pbxs and 234Th/210Pbxs ARs) in particles sampled under different hydrological conditions. The particulate 7Be/210Pbxs AR varies along the fluvial estuarine system mainly due to variations in 7Be activities, controlled by riverine, oceanic and atmospheric inputs and by resuspension of old 7Be-deficient sediments. These processes vary with river discharge, tidal cycle and season. Therefore, seasonal particle transport processes can be described using variations of the SPM 7Be/210Pbxs ARs. During high river discharge, the SPM 7Be/210Pbx ARs decrease from river to the ocean. The turbidity maximum zone (TMZ) is dispersed and the particles, and the associated contaminants, are rapidly transported from river to coastal waters, without significant retention within the TMZ. During low river discharge, the TMZ intrudes into the fluvial estuary, and the lowest 7Be/210Pbx ARs are observed there due to resuspension of 7Be-deficient sediments. Away from the TMZ, from the middle to lower estuary, SPM 7Be/210Pbx ARs increase, indicating that the particles have been recently tagged with 7Be. We explain this trend as being caused by marine input of dissolved radionuclides, as traced by SPM 234Th/210Pbxs ARs, followed by scavenging in the estuary. This result indicates that particle transport models based on 7Be and trace-metal budgets must consider oceanic dissolved inputs as an additional source of 7Be and, possibly, of contaminants to

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

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

    et al.: Fresh water influence on nutrient stoichiometry in a tropical estuary, Southwest coast of India - 57 - APPLIED ECOLOGY AND ENVIRONMENTAL RESEARCH 6(1): 57-64. http://www.ecology.uni-corvinus.hu ● ISSN 1589 1623  2008, Penkala Bt... estuary, Southwest coast of India - 58 - APPLIED ECOLOGY AND ENVIRONMENTAL RESEARCH 6(1): 57-64. http://www.ecology.uni-corvinus.hu ● ISSN 1589 1623  2008, Penkala Bt., Budapest, Hungary natural and anthropogenic factors influencing the geochemistry...

  15. Estuaries of southwest England: Salinity, suspended particulate matter, loss-on-ignition and morphology

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

    2015-09-01

    Analyses of consistently measured survey data and published hydrological data for the estuaries of southwest England show that: (1) freshwater runoff and estuary length are strongly related to catchment area; (2) salt intrusion length is always greater than 74% of the estuary length during low runoff, spring-tide summer conditions and, on average, is more than 90% - there is a statistically significant relationship between salt intrusion length and tidal range (increased intrusion) and freshwater runoff (decreased intrusion); (3) salinity stratification is strongly, positively correlated with the Simmons' Ratio - a measure of the relative balance of freshwater- and tidally-induced current speeds; (4) residence times are strongly correlated with tidal range and tidal length and somewhat less strongly correlated with tidal prism - longer estuaries with smaller tides have longer residence times than shorter estuaries with stronger tides; (5) maximum surface suspended particulate matter (SPM) concentrations vary from 2 to 20,000 mg l-1; (6) maximum surface SPM concentrations are strongly related both to tidal range and tidal length and less strongly correlated with tidal prism - long, strongly tidal estuaries have greater concentrations; (7) loss-on-ignition (LOI) of SPM is strongly related to SPM concentration - low concentrations (less than a few mg l-1) typically have LOI > 50% and high concentrations (greater than a few hundred mg l-1) typically have LOI ∼ 10%; (8) LOI of the freshwater SPM is greater than that in the area of maximum estuarine SPM concentration, so that SPM within the high-turbidity reaches of southwest estuaries is significantly different from that entering the estuaries in their freshwater inflows; (9) an observed scaling relationship between estuary tidal length and a prescribed function both of depth at the mouth and tidal range is similar to that given by theoretical work (Prandle, 2004; Prandle et al., 2006), as is an observed scaling

  16. The particulate {sup 7}Be/{sup 210}Pb{sub xs} and {sup 234}Th/{sup 210}Pb{sub xs} activity ratios as tracers for tidal-to-seasonal particle dynamics in the Gironde estuary (France): Implications for the budget of particle-associated contaminants

    Saari, Hanna-Kaisa [Universite de Bordeaux, UMR5805 EPOC, F-33405 Talence Cedex (France); Schmidt, Sabine, E-mail: s.schmidt@epoc.u-bordeaux1.fr [CNRS, UMR5805 EPOC, F-33405 Talence Cedex (France); Castaing, Patrice; Blanc, Gerard [Universite de Bordeaux, UMR5805 EPOC, F-33405 Talence Cedex (France); Sautour, Benoit [Universite de Bordeaux, UMR5805 EPOC, Station Marine d' Arcachon, F-33120 Arcachon (France); Masson, Olivier [IRSN, BP 3, 13115 Saint Paul Lez Durance (France); Cochran, J. Kirk [Marine Sciences Research Center, School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, New York 11794-5000 (United States)

    2010-09-15

    The short-lived natural radionuclides {sup 7}Be (T{sub 1/2} = 53 days), {sup 234}Th{sub xs} (T{sub 1/2} = 24.1 days) and {sup 210}Pb{sub xs} (T{sub 1/2} = 22.3 years), i.e. {sup 234}Th and {sup 210}Pb in excesses of that supported within particles by the decay of their parent isotopes, were analysed in suspended particulate matter (SPM) to study the particle dynamics in the Gironde fluvial estuarine system (France), strongly impacted by heavy metal pollution. From surveys of this land-ocean interface in 2006 and 2007, we established a times series of these radioisotopes and of their activity ratios ({sup 7}Be/{sup 210}Pb{sub xs} and {sup 234}Th/{sup 210}Pb{sub xs} ARs) in particles sampled under different hydrological conditions. The particulate {sup 7}Be/{sup 210}Pb{sub xs} AR varies along the fluvial estuarine system mainly due to variations in {sup 7}Be activities, controlled by riverine, oceanic and atmospheric inputs and by resuspension of old {sup 7}Be-deficient sediments. These processes vary with river discharge, tidal cycle and season. Therefore, seasonal particle transport processes can be described using variations of the SPM {sup 7}Be/{sup 210}Pb{sub xs} ARs. During high river discharge, the SPM {sup 7}Be/{sup 210}Pb{sub x} ARs decrease from river to the ocean. The turbidity maximum zone (TMZ) is dispersed and the particles, and the associated contaminants, are rapidly transported from river to coastal waters, without significant retention within the TMZ. During low river discharge, the TMZ intrudes into the fluvial estuary, and the lowest {sup 7}Be/{sup 210}Pb{sub x} ARs are observed there due to resuspension of {sup 7}Be-deficient sediments. Away from the TMZ, from the middle to lower estuary, SPM {sup 7}Be/{sup 210}Pb{sub x} ARs increase, indicating that the particles have been recently tagged with {sup 7}Be. We explain this trend as being caused by marine input of dissolved radionuclides, as traced by SPM {sup 234}Th/{sup 210}Pb{sub xs} ARs

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

    Revichandran, C.; Pylee, A.

    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...

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

    Pednekar, Suraksha M.; Matondkar, S. G. Prabhu; Gomes, Helga Do R.; Goes, Joaquim I.; Parab, Sushma; Kerkar, Vijaya

    2011-06-01

    In May of 2007, a study was initiated by the National Institute of Oceanography (NIO), Goa, India, to investigate the influence of monsoonal rainfall on hydrographic conditions in the Mandovi River of India. The study was undertaken at a location ˜2 km upstream of the mouth of this estuary. During the premonsoon (PreM) in May, when circulation in the estuary was dominated by tidal activity, phytoplankton communities in the high saline (35-37 psu) waters at the study site were largely made up of the coastal neritic species Fragilaria oceanica, Ditylum brightwellii and Trichodesmium erythraeum. During the later part of the intermonsoon (InterM) phase, an abrupt decline in salinity led to a surge in phytoplankton biomass (Chlorophyll a ˜14 mg m - 3), of a population that was dominated by Thalassiosira eccentricus. As the southwest monsoon (SWM) progressed and the estuary freshened salinity and Chlorophyll a (Chl a) concentrations decreased during the MoN, Skeletonema costatum established itself as the dominant form. Despite the low biomass (Chl a <2 mg m - 3), the phytoplankton community of the MoN was the most diverse of the entire study. During the postmonsoon (PostM), the increase in salinity was marked by a surge in dinoflagellate populations comprising of Ceratium furca, Akashiwo sanguinea, and Pyrophacus horologium.

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

    Suraksha M Pednekar; S G Prabhu Matondkar; Helga Do R Gomes; Joaquim I Goes; Sushma Parab; Vijaya Kerkar

    2011-06-01

    In May of 2007, a study was initiated by the National Institute of Oceanography (NIO), Goa, India, to investigate the influence of monsoonal rainfall on hydrographic conditions in the Mandovi River of India. The study was undertaken at a location ∼2 km upstream of the mouth of this estuary. During the premonsoon (PreM) in May, when circulation in the estuary was dominated by tidal activity, phytoplankton communities in the high saline (35–37 psu) waters at the study site were largely made up of the coastal neritic species Fragilaria oceanica, Ditylum brightwellii and Trichodesmium erythraeum. During the later part of the intermonsoon (InterM) phase, an abrupt decline in salinity led to a surge in phytoplankton biomass (Chlorophyll ∼14 mg m−3), of a population that was dominated by Thalassiosira eccentricus. As the southwest monsoon (SWM) progressed and the estuary freshened salinity and Chlorophyll (Chl ) concentrations decreased during the MoN, Skeletonema costatum established itself as the dominant form. Despite the low biomass (Chl > 2 mg m−3), the phytoplankton community of the MoN was the most diverse of the entire study. During the postmonsoon (PostM), the increase in salinity was marked by a surge in dinoflagellate populations comprising of Ceratium furca, Akashiwo sanguinea, and Pyrophacus horologium.

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

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

    Study of the characteristics of currents and water-level variations in the Cochin estuary reveals, for the first time, unique signatures of mixed standing-waves in the southern region. Analysis of the simultaneous water-level data generated...

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

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

    by Integrated Coastal and Marine Area Management(ICMAM-PD), Ministry of Earth Sciences, Chennai. Author, Vinita Janardanan is also grateful to Council of Scientific and Industrial Research (CSIR), New Delhi for financial support in the form of a senior...-flat area during a period of eutrophication. Marine Biology, 111, 293-301. 5. Dame, R. F., & Allen, D. M. (1996). Between estuaries and the sea. Journal of Experimental Marine Biology and Ecology, 200, 169-185. 6. Dame, R. F., Chliders, D.,Koepfler, E...

  2. The estuarine geochemical reactivity of Zn isotopes and its relevance for the biomonitoring of anthropogenic Zn and Cd contaminations from metallurgical activities: Example of the Gironde fluvial-estuarine system, France

    Petit, Jérôme C. J.; Schäfer, Jörg; Coynel, Alexandra; Blanc, Gérard; Chiffoleau, Jean-François; Auger, Dominique; Bossy, Cécile; Derriennic, Hervé; Mikolaczyk, Mathilde; Dutruch, Lionel; Mattielli, Nadine

    2015-12-01

    Zinc stable isotopes measurements by MC-ICP-MS, validated by laboratory intercalibrations, were performed on wild oysters, suspended particles and filtered river/estuarine water samples to provide new constraints for the use of Zn isotopes as environmental tracers. The samples selected were representative of the long range (400 km) transport of metal (Zn, Cd, etc.) contamination from former Zn-refining activities at Decazeville (i.e. δ66Zn > 1‰) and its phasing out, recorded during 30 years in wild oysters from the Gironde Estuary mouth (RNO/ROCCH sample bank). The study also addresses additional anthropogenic sources (urban and viticulture) and focuses on geochemical reactivity of Zn in the turbidity gradient and the maximum turbidity zone (MTZ) of the fluvial Gironde Estuary. In this area, dissolved Zn showed a strong removal onto suspended particulate matter (SPM) and progressive enrichment in heavy isotopes with increasing SPM concentrations varying from δ66Zn = -0.02‰ at 2 mg/L to +0.90‰ at 1310 mg/L. These signatures were attributed to kinetically driven adsorption due to strongly increasing sorption sites in the turbidity gradient and MTZ of the estuary. Oysters from the estuary mouth, contaminated sediments from the Lot River and SPM entering the estuary showed parallel historical evolutions (1979-2010) for Zn/Cd ratios but not for δ66Zn values. Oysters had signatures varying from δ66Zn = 1.43‰ in 1983 to 1.18‰ in 2010 and were offset by δ66Zn = 0.6-0.7‰ compared to past (1988) and present SPM from the salinity gradient. Isotopic signatures in river-borne particles entering the Gironde Estuary under contrasting freshwater discharge regimes during 2003-2011 showed similar values (δ66Zn ≈ 0.35 ± 0.03‰; 1SD, n = 15), i.e. they were neither related to former metal refining activities at least for the past decade nor clearly affected by other anthropogenic sources. Therefore, the Zn isotopic signatures in Gironde oysters reflect the

  3. Southwest monsoon influences the water quality and waste assimilative capacity in the Mandovi estuary (Goa state, India)

    VishnuRadhan, R.; Sagayadoss, J.; Seelan, E.; Vethamony, P.; Shirodkar, P.V.; Zainudin, Z.; Shirodkar, S.

    organic and inorganic material [6] that transport large quantities of natural and anthropogenic materials to the coastal water. The estuaries are peculiar ecosystems exhibiting both freshwater and marine characteristics and are the most productive..., the physical and chemical properties swing between pre- monsoon, monsoon and the post-monsoon seasons as per the runoff and river discharge. The ecosystem and natural habitats associated with these estuaries routinely adjust to these seasonal changes [10...

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

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

    Udupi region. Current Meters (RCM-7) were moored on 6 12 May 1997 off Swarna estuary at 13°28'N and 74°38'E with a clearance of 2 m both from surface and bottom (water depth of 12m) and retrieved on 27 May 1997. The current meters were set to sample...

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

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

    ′ E) extends between the cities of Azhikode in the north and Alleppey in the south, running parallel to the Arabian Sea (Figure 1). The estuarine system has two permanent openings, one at Cochin bar and the other at Azhikode. The Cochin bar mouth...–25% in the winter monsoon (November-December) [15, 16]. The human intervention in the Cochin Estuary dates back to 1836 but has accelerated during the last five decades. The booming city of Cochin, which is the largest in the west coast of India after Mumbai, has a...

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

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

    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.

  7. Toxic Metals Enrichment in the Surficial Sediments of a Eutrophic Tropical Estuary (Cochin Backwaters, Southwest Coast of India

    G. D. Martin

    2012-01-01

    Full Text Available 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 charaterstics and organic matter content. A principal component analysis distinguished three zones with different metal accumulation capacity: (i highest levels in north estuary, (ii moderate levels in central zone, and (iii lowest levels in southern part. Trace metal enrichments are mainly due to anthropogenic contribution of industrial, domestic, and agricultural effluents, whose effect is enhanced by settling of metals due to organic flocculation and inorganic precipitation associated with salinity changes. Enrichments factors using Fe as a normalizer showed that metal contamination was the product of anthropogenic activities. An assessment of degree of pollution-categorized sediments as moderately polluted with Cu and Pb, moderately-to-heavily polluted with Zn, and heavily-to-extremely polluted with Cd. Concentrations at many sites largely exceed NOAA ERL (e.g., Cu, Cr, and Pb or ERM (e.g., Cd, Ni, and Zn. This means that adverse effects for benthic organisms are possible or even highly probable.

  8. Metagenomic 16s rRNA investigation of microbial communities in the Black Sea estuaries in South-West of Ukraine.

    Bobrova, Oleksandra; Kristoffersen, Jon Bent; Oulas, Anastasis; Ivanytsia, Volodymyr

    2016-01-01

    The Black Sea estuaries represent interfaces of the sea and river environments. Microorganisms that inhabit estuarine water play an integral role in all biochemical processes that occur there and form unique ecosystems. There are many estuaries located in the Southern-Western part of Ukraine and some of them are already separated from the sea. The aim of this research was to determine the composition of microbial communities in the Khadzhibey, Dniester and Sukhyi estuaries by metagenomic 16S rDNA analysis. This study is the first complex analysis of estuarine microbiota based on isolation of total DNA from a biome that was further subjected to sequencing. DNA was extracted from water samples and sequenced on the Illumina Miseq platform using primers to the V4 variable region of the 16S rRNA gene. Computer analysis of the obtained raw sequences was done with QIIME (Quantitative Insights Into Microbial Ecology) software. As the outcome, 57970 nucleotide sequences were retrieved. Bioinformatic analysis of bacterial community in the studied samples demonstrated a high taxonomic diversity of Prokaryotes at above genus level. It was shown that majority of 16S rDNA bacterial sequences detected in the estuarine samples belonged to phyla Cyanobacteria, Proteobacteria, Bacteroidetes, Actinobacteria, Verrucomicrobia, Planctomycetes. The Khadhzibey estuary was dominated by the Proteobacteria phylum, while Dniester and Sukhyi estuaries were characterized by dominance of Cyanobacteria. The differences in bacterial populations between the Khadzhibey, Dniester and Sukhyi estuaries were demonstrated through the Beta-diversity analysis. It showed that the Khadzhibey estuary's microbial community significantly varies from the Sukhyi and Dniester estuaries. The majority of identified bacterial species is known as typical inhabitants of marine environments, however, for 2.5% of microbial population members in the studied estuaries no relatives were determined. PMID:26929931

  9. Intra-annual variability in nutrients in the Godavari estuary, India

    Sarma, V.V.S.S.; Prasad, V.R.; Kumar, B.S.K.; Rajeev, K.; Devi, B.M.M.; Reddy, N.P.C.; Sarma, V.V.; DileepKumar, M.

    .V., Lecroart, P., Abril, G., 2007. The dynamics of phosphorus in turbid estuarine system: Example of the Gironde estuary (France). Limnology and Oceanography 52, 862-872. Del Amo, Y., Le Pape, O., Treguer, P., Queguiner, B., Menesguen, A., Aminot, A., 1997.... Impacts of high-nitrate feshwater inputs on macrotidal ecosystems. I. Seasonal evolution of nutrient limitation for the diatom-dominated phytoplankton of the Bay of Bresh (France). Marine Ecology Progress Series 161, 213-224. De Wit, R., Stal, L...

  10. Initiation of winter phytoplankton blooms within the Gironde plume waters in the Bay of Biscay

    Labry, Claire; Herbland, Alain; Delmas, Daniel; Laborde, P.; Lazure, Pascal; Froidefond, J; Jegou, Anne-marie; Sautour, B.

    2001-01-01

    Thermostratification and seasonal Light increase are generally considered the first causes of phytoplankton spring blooms in temperate waters. The objective of this study is to confirm the existence of winter phytoplankton blooms, responsible for the early exhaustion of phosphate, within the Gironde plume waters (southeast Bay of Biscay), and to understand what may initiate them so early. Two cruises, BIOMET 2 and BIOMET 3, were carried out respectively in early (8 to 21 January) and late win...

  11. Diagnostic écologique des milieux aquatiques du Palus de Molua (Gironde)

    Vandenhende, M.

    2008-01-01

    As part of a plan of a National Natural Reserve, the ecological quality of aquatic environment in the « Palus de Molua », a vast wetland located in the north of Gironde in France, was assessed during 5 months. A specific study protocol was established. The physicochemical quality of water and sediments, and the phytoplankton et macrophytes communities were analysed. The different sites studied seem to be independent from each others. The physicochemical quality of water and sediments seems to...

  12. Climatic facilitation of the colonization of an estuary by Acartia tonsa.

    Chaalali, Aurélie; Beaugrand, Grégory; Raybaud, Virginie; Goberville, Eric; David, Valérie; Boët, Philippe; Sautour, Benoit

    2013-01-01

    Global change has become a major driving force of both terrestrial and marine systems. Located at the interface between these two realms, estuarine ecosystems are probably the place where both direct and indirect effects of human activities conspire together to affect biodiversity from phytoplankton to top predators. Among European estuarine systems, the Gironde is the largest estuary of Western Europe and many studies have provided evidence that it has been affected by a variety of anthropogenic stressors such as thermal and chemical pollution, physical alterations and exploitation, especially for maritime traffic. In such a context, species introduction is also a current major issue with the establishment of strong competitive species that could lead to ecosystem reorganization with potential decrease or even disappearance of native species. In the Gironde estuary, this hypothesis was proposed for the invasive shrimp species Palaemon macrodactylus as a decrease in the native species abundance was observed at the same time. Although species introduction often takes place via ballast water, the influence of climate-driven changes on the establishment of new species remains a key issue. The calanoid copepod Acartia tonsa, observed in the Gironde estuary for the first time in 1983, have since colonized most part of the estuary, reaching a level of abundance comparable to the dominant native species Eurytemora affinis. In this study, using both the concept of the ecological niche sensu Hutchinson (fundamental and realized niches) and statistical models, we reveal that the dynamics of the colonization of A. tonsa was facilitated by environmental conditions that have become closer to its environmental optimum with respect to temperature and salinity. PMID:24098656

  13. Conditions for tidal bore formation in convergent alluvial estuaries

    Bonneton, Philippe; Filippini, Andrea Gilberto; Arpaia, Luca; Bonneton, Natalie; Ricchiuto, Mario

    2016-04-01

    Over the last decade there has been an increasing interest in tidal bore dynamics. However most studies have been focused on small-scale bore processes. The present paper describes the first quantitative study, at the estuary scale, of the conditions for tidal bore formation in convergent alluvial estuaries. When freshwater discharge and large-scale spatial variations of the estuary water depth can be neglected, tide propagation in such estuaries is controlled by three main dimensionless parameters: the nonlinearity parameter ε0 , the convergence ratio δ0 and the friction parameter ϕ0. In this paper we explore this dimensionless parameter space, in terms of tidal bore occurrence, from a database of 21 estuaries (8 tidal-bore estuaries and 13 non tidal-bore estuaries). The field data point out that tidal bores occur for convergence ratios close to the critical convergence δc. A new proposed definition of the friction parameter highlights a clear separation on the parameter plane (ϕ0,ε0) between tidal-bore estuaries and non tidal-bore estuaries. More specifically, we have established that tidal bores occur in convergent estuaries when the nonlinearity parameter is greater than a critical value, εc , which is an increasing function of the friction parameter ϕ0. This result has been confirmed by numerical simulations of the two-dimensional Saint Venant equations. The real-estuary observations and the numerical simulations also show that, contrary to what is generally assumed, tide amplification is not a necessary condition for tidal bore formation. The effect of freshwater discharge on tidal bore occurrence has been analyzed from the database acquired during three long-term campaigns carried out on the Gironde/Garonne estuary. We have shown that in the upper estuary the tidal bore intensity is mainly governed by the local dimensionless tide amplitude ε. The bore intensity is an increasing function of ε and this relationship does not depend on freshwater

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

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

  15. Local heritage to singularize a wine terroir: the example of pays Foyen (Gironde, France

    Chantal Crenn

    2007-04-01

    Full Text Available Le vin, enjeu culturel et économique, se trouve aujourd’hui au cœur de dynamiques locales œuvrant à produire de la différence : souvent sous l’impulsion de néoruraux, des éléments naturels et d’histoire locale sont sélectionnés et mobilisés pour recomposer un patrimoine fondateur d’identité, fabriquer une authenticité, et donc légitimer des pratiques. Cet article propose d’observer le phénomène de patrimonialisation afin de comprendre comment les frontières se sont progressivement resserrées autour d’un vin régional devenu un vin local, à travers l’exemple d’un espace viti-vinicole, le Pays Foyen (Gironde, France. Après avoir éclairé les tensions théoriques entre global et local, nous nous intéressons particulièrement au processus de territorialisation et de construction identitaire lié à la mise en valeur du « local » dans le produit.Wine, as a cultural and economic product, is today at the heart of local dynamics working towards producing singularity: often under the impulse of neorurals, elements from the local environment and history are selected and used to recompose a heritage which creates an identity, to make up authenticity, therefore to legitimize specific practices. This paper aims at highlighting the current phenomenon of patrimonialization in order to understand how a regional wine turned into a local wine through the observation of a wine terroir, the Pays Foyen (Gironde, France. After theoretic considerations on global/local tensions, we’ll concentrate on spatial definitions and identity construction linked to the promotion of “locality” in the product.

  16. Estuary regime

    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)

  17. Tidal circulation and salinity distribution in the Mandovi and Zuari estuaries: Case study

    Manoj, N.T.; Unnikrishnan, A.S.

    was to study the intraseasonal variations of salinity during the breaks in the southwest monsoon. A hybrid network numerical model was used for the present study to simulate the tidal circulation and the salinity distribution in these estuaries. The model...

  18. Radiotracer studies of the dispersion of solid pollutants in marine and estuarial environments. Measurements of diffusion coefficients and phenomenon of dispersion by currents

    The transfer in suspension of solid particles which may be pollutant vectors is deduced from studies in a natural environment of the circulation, dispersion and decantation of suspensions created by artificial discharge or by erosion of the bed. In the Gironde estuary, where the tide comes in 90 km, radiotracer experiments describe and quantify the transfers of sediments eroded from the bottom of the principal channel to the secondary channel and their return upstream. A mechanism whereby silts move upstream produces progressive dilution of 90% of the eroded material, while a rapid transfer system causing 10% to move upstream produces far less thorough dilution. Both in the Gironde estuary and in the Baie de la Seine, hydrodynamic dispersion is a phenomenon of negligible importance during the first hours after discharge of erosion. The suspensions are diluted by decantation and the artificial discharges circulate in high concentrations around the discharge point. The measured dispersion coefficients are generally less than 0.5 m2/s. (author)

  19. Estuary Classification Revisited

    Guha, Anirban; Lawrence, Gregory A.

    2012-01-01

    This paper presents the governing equations of a tidally-averaged, width-averaged, rectangular estuary in completely nondimensionalized forms. Subsequently, we discover that the dynamics of an estuary is entirely controlled by only two variables: (i) the Estuarine Froude number, and (ii) a nondimensional number related to the Estuarine Aspect ratio and the Tidal Froude number. Motivated by this new observation, the problem of estuary classification is re-investigated. Our analysis shows that ...

  20. Prediction in Ungauged Estuaries

    J. I. A. Gisen

    2015-01-01

    Estuaries have been used for settlement by humans since 5000-9000 years ago [Day et al., 2012]. The calm environment and nutrient-rich soil encouraged the development of ports and agriculture. Over-development however has put estuaries in unhealthy condition, where the water is polluted (excessive nutrient or salt intrusion problem) and natural morphodynamic equilibrium is disturbed. This implies that the need for effective estuarine management is crucial. Unfortunately, most of the estuaries...

  1. Estuary Classification Revisited

    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.

  2. From seasonal patterns to a reference situation in an estuarine environment: Example of the small fish and shrimp fauna of the Gironde estuary (SW France)

    2006-01-01

    Detecting changes in animal communities suggests that a reference situation exists. It is a particularly difficult task in estuarine environments that are complex and fluctuate with time. Effects of human pressures are difficult to assess due to the scarcity or even the lack of evaluation and monitoring systems. In order to detect anomalies in the functioning of the system and to identify effects of perturbations upon populations and communities, it is necessary to analyse the dynamics in ord...

  3. Exploitation of trophic resources by fish under stressful estuarine conditions

    Pasquaud, S.; David, V.; Lobry, J.; Girardin, M.; Sautour, B.; ELIE P.

    2010-01-01

    Despite the high complexity and variability of estuaries, these ecosystems are very productive and play an important role in fish feeding. This paper constitutes a preliminary investigation to test how fish optimize the use of the available trophic resources, by studying trophic preference variability and feeding strategies of some pelagic and demersal fish in the Gironde estuary (southwest France). Fish and their prey were collected approximately every two months from July 2003 to June 2004 ...

  4. Penobscot Estuary (Maine) Monitoring

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA's NEFSC collects fisheries data from the Penobscot Estuary using several types of fishing gear. The data is used to determine species presence, relative...

  5. Bibliography on Alaska estuaries

    US Fish and Wildlife Service, Department of the Interior — This bibliography was compiled to assist in working up “profiles” for the estuaries in Alaska. The purpose of the profiles is to list in a narrative form the...

  6. Can analysis of Platichthys flesus otoliths provide relevant data on historical metal pollution in estuaries? Experimental and in situ approaches.

    Selleslagh, Jonathan; Echard, Aurélie; Pécheyran, Christophe; Baudrimont, Magalie; Lobry, Jérémy; Daverat, Françoise

    2016-07-01

    were complex, the concentrations were correlated with those in the water. Analysis of flounder specimens collected from 2007 to 2014 in the Gironde estuary (SW France) showed interannual variability in Pb concentrations, with higher values for fish otoliths from 2007 to 2010 than those from 2012 to 2014. This trend indicated a decrease in Pb in the Gironde estuary over the last decade, which is consistent with the results of other surveys on bivalves. Our study demonstrates that it is possible to use otolith microchemistry as a tool in assessing and retracing long-term metal pollution in estuarine systems. PMID:26994790

  7. 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...

  8. South and Southwest HSRC

    Federal Laboratory Consortium — The Hazardous Substance Research Center/South and Southwest is a competitively awarded, peer-reviewed research consortium led by Louisiana State University with the...

  9. Alimentation humaine au cours du Magdalénien en Gironde d’après les teneurs en isotopes stables (13C, 15N) du collagène

    Drucker, Dorothée G.; Henry-Gambier, Dominique; Lenoir, Michel

    2010-01-01

    Nous proposons une étude de l’alimentation humaine au cours du Magdalénien en Gironde qui intègre les derniers développements méthodologiques des reconstitutions basées sur les teneurs en isotopes stables (13C, 15N) du collagène. Lors d’un précédent travail (Drucker et Henry-Gambier 2005), la reconstitution isotopique du régime alimentaire de la femme de Saint-Germain-la-Rivière (Gironde) a bénéficié de l’application d’un modèle mathématique d’équation de mélange linéaire (Phillips et Koch 20...

  10. Ecology of estuaries

    Ecology of Estuaries: Anthropogenic Effects represents the most definitive and comprehensive source of reference information available on the human impact on estuarine ecosystems. The book discusses both acute and insidious pollution problems plaguing these coastal ecotones. It also provides a detailed examination of the deleterious and pervasive effects of human activities on biotic communities and sensitive habitat areas in estuaries. Specific areas covered include organic loading, oil pollution, polynuclear aromatic hydrocarbons, chlorinated hydrocarbons, heavy metals, dredging and dredge-spoil disposal, radionuclides, as well as other contaminants and processes. The diverse components of these anthropogenic influences are assembled in an organized framework and presented in a clear and concise style that will facilitate their understanding

  11. Indian estuaries: Dynamics, ecosystems, and threats

    Shetye, S.R.

    ARTICLE Indian estuaries: Dynamics, ecosystems, and threats Satish R. Shetye National Institute of Oceanography Dona Paula, Goa - 403 004. e-mail: shetye@nio.org Received May 11, 2011 Abstract Indian estuaries have special features that are derived from... the tide pulls the mixed water out of the estuary through its mouth. Different processes within an estuary contribute to mixing of the two waters, the important among these in the Mandovi estuary are: influence of the tide on the advective field within...

  12. FLORA OF MOLOCHNYI ESTUARY COASTS

    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.

  13. Summer monsoon onset-induced changes of autotrophic pico- and nanoplankton in the largest monsoonal estuary along the west coast of India.

    Mohan, Arya P; Jyothibabu, R; Jagadeesan, L; Lallu, K R; Karnan, C

    2016-02-01

    This study presents the response of autotrophic pico- and nanoplankton to southwest monsoon-associated hydrographical transformations in the Cochin backwaters (CBW), the largest monsoonal estuary along the west coast of India. By the onset of the southwest monsoon, the euhaline/mesohaline conditions in the downstream/upstream of CBW usually transform into oligohaline/limnohaline. The flow cytometer analysis revealed the dominance of picoeukaryotes > Synechococcus > nanoautotrophs, with Prochlorococcus either very low or entirely absent. Synechococcus abundance was high during the pre-southwest monsoon (10(6) L(-1)), which dwindled with heavy fresh water influx during the southwest monsoon (10(5) L(-1)). The drastic drop in salinity and faster flushing of the CBW during the southwest monsoon replaced the euhaline/mesohaline strain of Synechococcus with an oligohaline/limnohaline strain. Epifluorescence microscopy analyses showed that, among the two strains of Synechococcus, the phycoerythrin-rich (PE-rich) one was dominant in the mesohaline/euhaline conditions, whereas the phycocyanin-rich (PC-rich) strain dominated in oligohaline/limnohaline conditions. Although Synechococcus abundance diminished during the southwest monsoon, the total abundance of picoplankton community remained virtually unchanged in the upstream due to an increase in the abundance of picoeukaryotes. On the other hand, the autotrophic nanoplankton abundance increased from pre-monsoon levels of av. 3.8 × 10(6)-av. 9.5 × 10(6) L(-1) at the onset of the southwest monsoon. Utilizing suitable multivariate analyses, the study illustrated the differential response and niche preference of various smaller communities of autotrophs to the southwest monsoon-associated hydrographical ramifications in a large monsoonal estuary, which may be applicable to similar such estuaries situated along the Indian coastline. PMID:26780412

  14. KNOW YOUR ESTUARY: THE WATER THROUGH TIME

    This presentation will focus on historical changes in water quality in the Yaquina Estuary, Oregon, and factors which influence water quality within this estuary. Topics presented will include the importance of ocean conditions on water quality in the estuary; historical changes...

  15. Tracking the turbidity maximum zone in the Loire Estuary (France) based on a long-term, high-resolution and high-frequency monitoring network

    Jalón-Rojas, Isabel; Schmidt, Sabine; Sottolichio, Aldo; Bertier, Christine

    2016-04-01

    A unique dataset of turbidity from 7 years of continuous monitoring at six stations, distributed evenly along a 62-km long transect, is presented to discuss, for the first time, the present-day dynamics of the turbidity maximum zone (TMZ) in the Loire Estuary. This system is considered one of the largest macrotidal, hyper-turbid estuaries of the European coast, mainly as the result of intense engineering works in the last two centuries. Besides accurate TMZ tracking, from tidal to multi-annual time scales, the high temporal and spatial resolution of measurements allows us to address TMZ aspects scarcely reported in the literature on estuarine sedimentary dynamics. In the Loire Estuary, TMZ moves upstream during periods of low discharge and its upstream boundary may reach up to 62 km from the mouth. The TMZ displacement is faster during its downstream flushing by river floods than during its upstream migration by tidal pumping (respectively 1.6 km day-1 and 0.9 km day-1 during 2011). However, the expulsion of the TMZ from the upper reaches requires higher discharge levels than its installation (respective discharge thresholds of 497-1034 m3 s-1 and 300-360 m3 s-1). This is due to the presence of mobile mud remaining after the TMZ presence, as confirmed by clockwise turbidity-discharge hysteresis patterns. While the installation threshold barely varies over years, the expulsion threshold is higher during years with a more concentrated and persistent TMZ. The interannual variability of the TMZ concentration and persistence is explained by the water volume transported during the previous high discharge period and the duration of the low discharge period, respectively, as recently shown for the Gironde Estuary, leading to a better understanding of TMZ features in macrotidal estuaries. The summer-averaged river flow is introduced as a hydrological indicator of the upstream boundary of the TMZ. In the context of global change, these three discharge-based indicators of TMZ

  16. Biogeochemical budgets for Tapi Estuary

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

    , is rural with no sewage facilities. The urban population is spread over 37 cities (7 class I cities with population >100,000; 7 class II cities with population between 50,000 and 100,000; and 23 class III cities with population ranging between 20..., chemical and metallurgical. All these industries release their effluents in the adjacent estuary. A considerable amount of sewage generated in and around the Surat city is released to the inner segment of the estuary. The average annual ground water...

  17. Biomarkers in Nereis diversicolor (Polychaeta: Nereididae) as management tools for environmental assessment on the southwest Iberian coast

    Gomes, Tania; González-Rey, María; Rodríguez-Romero, Araceli; Trombini, Chiara; Riba, Inmaculada; Blasco, Julián; Bebianno, Maria João

    2013-01-01

    [EN] The environmental quality of the southwest Iberian coast was assessed in different areas (Ria Formosa Lagoon, Guadiana Estuary and Cádiz Bay) focusing on metal contamination (Cd, Cu, Ni, Pb and Zn) in Nereis diversicolor whole tissues. In addition, associated toxicological effects were assessed using a multibiomarker approach combining several conventional biomarkers. The set of biomarkers selected included antioxidant enzymes (catalase, superoxide dismutase and glutathione peroxidase), ...

  18. Have the bioavailabilities of trace metals to a suite of biomonitors changed over three decades in SW England estuaries historically affected by mining?

    Rainbow, P S; Kriefman, S; Smith, B D; Luoma, S N

    2011-03-15

    Many estuaries of southwest England were heavily contaminated with toxic metals associated with the mining of copper and other metals, particularly between 1850 and 1900. The question remains whether the passage of time has brought remediation to these estuaries. In 2003 and 2006 we revisited sites in 5 metal-contaminated estuaries sampled in the 1970s and 1980s - Restronguet Creek, Gannel, West Looe, East Looe and Tavy. We evaluate changes in metal contamination in sediments and in metal bioavailabilities in sediments and water to local organisms employed as biomonitors. We find that the decline in contamination in these estuaries is complex. Differences in bioavailable contamination in the water column were detectable, as were significant detectable changes in at least some estuaries in bioavailable metal contamination originating from sediments. However, in the 100 years since mining activities declined, bioavailable contamination has not declined to the regional baseline in any estuary affected by the mine wastes. The greatest decline in contamination occurred in the one instance (East Looe) where a previous industrial source of (Ag) contamination was considered. We used the macroalgae Fucus vesiculosus and Ascophyllum nodosum as biomonitors of dissolved metal bioavailabilities and the deposit feeders Nereis diversicolor and Scrobicularia plana as biomonitors of bioavailable metal in sediments. We found no systematic decrease in the atypically high Ag, Cu, Pb and Zn concentrations in the estuarine sediments over a 26 year period. Accumulated metal (Ag, As, Cu, Pb, and Zn) concentrations in the deposit feeders are similarly still atypically high in at least one estuary for each metal, and there is no consistent evidence for general decreases in sediment metal bioavailabilities over time. We conclude that the legacy of mining in sheltered estuaries of southwest England is the ongoing presence of sediments rich in metals bioavailable to deposit feeders, while

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

    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 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)

  20. Modelling Suspended Sediment Transport in Monsoon Season: A Case Study of Pahang River Estuary, Pahang, Malaysia

    Zakariya, Razak; Ahmad, Zuhairi; Saad, Shahbudin; Yaakop, Rosnan

    2013-04-01

    Sediment transport based on 2-dimensional real time model was applied to Pahang River estuary, Pahang, Malaysia and has been evaluated and verified with time series of tidal elevation, flow and suspended sediment load. Period of modelling was during highest high tide and lowest low tide in Northeast Monsoon (NE) which happened in December 2010 and Southwest Monsoon (SW) in July 2011. Simulated model outputs has been verify using Pearson's coefficient and has showed high accuracy. The validated model was used to simulate hydrodynamic and sediment transport of extreme conditions during both monsoon seasons. Based on field measurement and model simulation, tidal elevation and flow velocity, freshwater discharge of Pahang River were found to be higher during NE Monsoon. Based on the fluxes, the estuary also showed 'ebb-dominant' characteristic during highest high tide and lowest low tide in NE monsoon and normal ebbing-flooding characteristics during SW monsoon. In the Pahang River estuary, inflow and outflow patterns were perpendicular to the open boundary with circular flow formed at the shallow area in the middle of estuary during both monsoons. Referring to sea water intrusion from the river mouth, both seasons show penetration of more than 9 km (upstream input boundary) during higher high water tide. During higher lower water tide, the water intrusion stated varies which 5.6km during NE monsoon and 7.8km during SW monsoon. Regarding to the times lap during high tide, the sea water takes 2.8 hours to reach 9km upstream during NE monsoon compared to 1.9 hour during SW monsoon. The averages of suspended sediment concentration and suspended sediment load were higher during Northeast monsoon which increased the sedimentation potentials.Total of suspended sediment load discharged to the South China Sea yearly from Pahang River is approximately 96727.5 tonnes/day or 3.33 tonnes/km2/day which 442.6 tonnes/day during Northeast Monsoon and 25.3 tonnes/day during Southwest

  1. Phosphorous speciation in surface sediments of the Cochin estuary.

    Gireeshkumar, T R; Deepulal, P M; Chandramohanakumar, N

    2013-03-01

    Sequential chemical extraction using chelating agents were used to study the P dynamics and its bioavailability along the surface sediments of the Cochin estuary (southwest coast of India). Sediments were analyzed for major P species (iron bound P, calcium bound P, acid soluble organic P, alkali soluble organic P and residual organic P), Fe, Ca, total carbon, organic carbon, total nitrogen and total sulfur contents. An abrupt increase in the concentration of dissolved inorganic P with increasing salinity was observed in the study region. Iron-bound P exhibited a distinct seasonal pattern with maximum values in the monsoon season when fresh water condition was prevailed in the estuary. As salinity increased, the percentage of iron-bound P decreased, while that of calcium-bound P and total sedimentary sulfur increased. C/P and N/P ratios were low which indicate that large amounts of organic matter enriched with P tend to accumulate in surface sediments. The high organic P contribution in the sedimentary P pool may indicate high organic matter load with incomplete mineralization, as well as comparatively greater percentage of humic substance and resistant organic compounds. Principal component analysis is employed to find the possible processes influencing the speciation of P in the study region and indicate the following processes: (1) the spatial and seasonal variations of calcium bound P and acid soluble organic P was mainly controlled by sediment texture and organic carbon content, (2) sediment redox conditions control the distribution of iron bound P and (3) the terrigenous input of organic P is a significant processes controlling total P content in surface sediments. The bioavailable P was very high in the surface sediments which on an average accounts for 59 % in the pre-monsoon, 65 % in the monsoon and 53 % in the post-monsoon seasons. The surface sediments act as a potential internal source of P in the Cochin estuary. PMID:22843296

  2. Oil spill trajectory analysis for the Calcasieu Estuary

    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 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

  3. Modeling of 226Ra behavior in a Spanish estuary affected by the phosphate industry

    The Odiel and Tinto rivers, southwest Spain, form a fully mixed estuary. An industrial area that includes a complex dedicated to the production of phosphate fertilizers is located by the Odiel River. This complex released phosphogypsum wastes directly to the Odiel River and also disposed them on open air piles located by the Tinto River. Due to new EU regulations, wastes are not directly released to the Odiel from 1998 on, although they are still disposed on the open air piles. The behavior of 226Ra in a system like this estuary is complex, since radionuclides are affected by tidal actions and interactions with sediments through adsorption/desorption reactions and erosion/deposition processes. A numerical 2D depth-averaged model of the estuary has been developed, including processes mentioned above. It has been applied to reproduce experimental data measured after a release from the industrial complex in the Odiel River and after an accidental release in the Tinto River from the gypsum piles. The model has also been applied to simulate the self-cleaning process observed in the estuary after the direct releases from the fertilizer complex were stopped. (author)

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

    K M, Rajaneesh; Mitbavkar, Smita

    2013-12-01

    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 salinity preferences with phycoerythrin-rich cells at salinities >2 (Synechococcus-PEI), >20 (Synechococcus-PEII) and segregation in the surface and near-bottom waters. During monsoon-break and non-monsoon period stabilized waters, increased salinity, temperature, solar radiation and low rainfall favored high Synechococcus abundance whereas unstable waters, increased turbidity and low solar radiation during active monsoon lowered abundance. SYN-PC positively co-related with nitrate and phosphate and SYN-PEI with phosphate. Synechococcus contribution to phytoplankton carbon biomass ranged from 9 to 29%. In monsoonal estuaries, rainfall intensity regulates freshwater runoff which modulates the estuarine environment, creating temporal-spatial niche segregation of Synechococcus groups thereby serving as indicator organisms of the estuarine hydrodynamics. PMID:24094891

  5. Study of the behaviour of trace elements in estuaries: experimental approaches and modeling

    Most of trace elements have a non conservative behavior in estuarine environments. It is the case of cadmium, cobalt and caesium for which the fate in estuarine and coastal zones is largely controlled by their distribution between water and suspended particles, which generally have high residence times or can be definitely deposited in these areas. Metallic contaminants and radionuclides can be present under various species: dissolved (mineral and organic complexes), colloidal and particulate forms (adsorbed, precipitated) or integrated by various mechanisms in the organisms. Such distributions are the result of processes (physical, chemical, biological) which are controlled by many factors (ionic strength, pH, Eh, major cations concentration, nature and concentration of suspended matter, primary production,...). Geochemical modeling is a very useful approach to understand the dynamics of this type of contaminant, especially in the complex systems which are the estuaries. A speciation model was used to simulate the measurements of dissolved and particulate Cd, Co and Cs, taken during various cruises carried out in the Seine, Loire, Gironde and Rhone estuaries. The model is able to reproduce the distribution of metals between the dissolved and particulate phases, and also to evaluate the concentrations of various chemical species (especially those which are most bio-available). The approach presented treats adsorption processes as a formation of inner sphere complexes with functional surface groups (surface complexation model) or as an cationic exchange reaction. The calculation of chemical species takes into account the presence of dissolved ligands or major cations of seawater, which compete with the metal for the surface sites. The model can consider the various natural particle components (metal oxy-hydroxides, organic matter) as individual adsorbent phases or treat natural particles in a 'global manner'. The choice of modeled processes is based on studies of

  6. 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...

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

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

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

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

  9. Morphodynamic equilibrium of alluvial estuaries

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

    2014-05-01

    The evolution of the longitudinal bed profile of an estuary, with given plan-form configuration, subject to given tidal forcing at the mouth and prescribed values of water and sediment supply from the river is investigated numerically. Our main goal is to ascertain whether, starting from some initial condition, the bed evolution tends to reach a unique equilibrium configuration asymptotically in time. Also, we investigate the morphological response of an alluvial estuary to changes in the tidal range and hydrologic forcing (flow and sediment supply). Finally, the solution helps characterizing the transition between the fluvially dominated region and the tidally dominated region of the estuary. All these issues play an important role also in interpreting how the facies changes along the estuary, thus helping to make correct paleo-environmental and sequence-stratigraphic interpretations of sedimentary successions (Dalrymple and Choi, 2007). Results show that the model is able to describe a wide class of settings ranging from tidally dominated estuaries to fluvially dominated estuaries. In the latter case, the solution is found to compare satisfactory with the analytical asymptotic solution recently derived by Seminara et al. (2012), under the hypothesis of fairly 'small' tidal oscillations. Simulations indicate that the system always moves toward an equilibrium configuration in which the net sediment flux in a tidal cycle is constant throughout the estuary and equal to the constant sediment flux discharged from the river. For constant width, the bed equilibrium profile of the estuarine channel is characterized by two distinct regions: a steeper reach seaward, dominated by the tide, and a less steep upstream reach, dominated by the river and characterized by the undisturbed bed slope. Although the latter reach, at equilibrium, is not directly affected by the tidal wave, however starting from an initial uniform stream with the constant 'fluvial' slope, the final

  10. Carbon dioxide emissions from Indian monsoonal estuaries

    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.

    be completely different from those in dry period. Recently Sarma et al. (2011) reported record levels of partial CO 2 pressures (pCO 2 ) of >30,000 μatm in the Godavari estuary during discharge period of 2008 whereas close to atmospheric saturation... was noticed during dry period. Similarly, enhanced pCO 2 levels during discharge period was also noticed in other Indian estuaries, such as Mandovi-Zuari (Sarma et al., 2001), Cochin estuary (Gupta et al., 2009), Chilka estuary (Gupta et al., 2008) whereas...

  11. Southwest Airlines: lessons in loyalty.

    D'Aurizio, Patricia

    2008-01-01

    Southwest Airlines continues to garner accolades in the areas of customer service, workforce management, and profitability. Since both the health care and airlines industries deal with a service rather than a product, the customer experience depends on the people who deliver that experience. Employees' commitment or "loyalty" to their customers, their employer, and their work translates into millions of dollars of revenue. What employee wants to work for "the worst employer in town?" Nine loyalty lessons from Southwest can be carried over to the health care setting for the benefit of employees and patients. PMID:19330974

  12. Cultural Arts in the Southwest.

    Cross, Kate

    1998-01-01

    Presents a pottery project for eighth-grade students based on a study of ancient and modern forms of Pueblo Indian pottery of the Southwest United States. Details the process for creating either carved, red clay, or painted white clay pottery typical of these cultural groups. Relates student reactions to the project. (DSK)

  13. Living in the twilight: estimating net phytoplankton growth in the Westerschelde estuary (The Netherlands) by means of an ecosystem model (MOSES)

    Soetaert, K.; Herman, P.M.J.; Kromkamp, J

    1994-01-01

    Net phytoplankton productivity in the Westerschelde, a relatively deep. highly turbid and eutrophic estuary in the Southwest Netherlands, was examined by means of a 13-compartment dynamic simulation model. The description of the light-Iimited primary production was based on the model of Eilers and Peeters (1988. Ecol. Model., 42, 185-198). This light limitation was parameterized to the different model compartments by integrating the Eilers-Peeters model over a day and over depth taking into a...

  14. Identification of thermohaline structure of a tropical estuary and its sensitivity to meteorological disturbance through temperature, salinity, and surface meteorological measurements

    Joseph, A.; Mehra, P.; Desai, R.G.P.; Sivadas, T.K.; Balachandran, K.K.; Vijaykumar, K.; Revichandran, C.; Agarvadekar, Y.; Francis, R.; Martin, G.D.

    to the Cochin harbor. Whereas these two inlets cause intrusion of saline water from the Arabian Sea, six rivers originating from the Western Ghats supply large quantities of fresh water into the estuary during the southwest and the northeast monsoonal seasons... features. Most importantly, no studies have been reported on the influence of meteorological disturbances on its thermohaline structure. Sensitivity of water level variability in KB to such disturbances has been reported elsewhere [4]. The parameters...

  15. SEMINATURAL SILVICULTURE IN SOUTHWEST GERMANY

    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.

  16. 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...

  17. Carbon isotope geochemistry in the Yalujiang estuary

    吴莹; 张经

    2001-01-01

    The distribution of particulate organic carbon (POC) along the lower reaches is similar between the dry season and the flood season in the Yalujiang Estuary, North China. However, the values of particulate organic carbon of the upperstream in the dry season are one magnitude lower than the concentrations in the flood season. Stable carbon isotope ratios have been used to study the sources of particulate organic carbon in the Yalujiang Estuary. The isotopic composition of POC shows a range from -23.1‰ to -29.4‰ with a little seasonal variation. The isotopic evidence indicates that the POC in the Yalujiang Estuary is predominantly of terrestrial origin rather than a result of in situ plankton. The study of the ratio of POC: Chla shows that the turbidity maximum plays an important role in POC cycle in the Yalujiang Estuary. Organic detritus and soil erosion are the main contributions to POC in the turbidity maximum, especially in the flood season.

  18. Mercury in sediments of Ulhas estuary

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

    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...

  19. Microplastic in three urban estuaries, China.

    Zhao, Shiye; Zhu, Lixin; Li, Daoji

    2015-11-01

    Estuarine Microplastics (MPs) are limited to know globally. By filtering subsurface water through 330 μm nets, MPs in Jiaojiang, Oujiang Estuaries were quantified, as well as that in Minjiang Estuary responding to Typhoon Soulik. Polymer matrix was analyzed by Raman spectroscopy. MP (plastics. The highest MPs density was found in Minjiang, following Jiaojiang and Oujiang. Fibers and granules were the primary shapes, with no pellets found. Colored MPs were the majority. The concentrations of suspended microplastics determine their bioavailability to low trophic organisms, and then possibly promoting the transfer of microplastic to higher trophic levels. Polypropylene and polyethylene were the prevalent types of MPs analyzed. Economic structures in urban estuaries influenced on MPs contamination levels. Typhoon didn't influence the suspended MP densities significantly. Our results provide basic information for better understanding suspended microplastics within urban estuaries and for managerial actions. PMID:26312741

  20. Wind-driven estuarine turbidity maxima in Mandovi Estuary, central west coast of India

    Pratima M Kessarkar; V Purnachandra Rao; R Shynu; Ishfaq Mir Ahmad; Prakash Mehra; G S Michael; D Sundar

    2009-08-01

    Systematic studies on the suspended particulate matter (SPM) measured on a seasonal cycle in the Mandovi Estuary, Goa indicate that the average concentrations of SPM at the regular station are ∼20mg/l, 5mg/l, 19mg/l and 5mg/l for June–September, October–January, February–April and May, respectively. SPM exhibits low-to-moderate correlation with rainfall indicating that SPM is also influenced by other processes. Transect stations reveal that the SPM at sea-end stations of the estuary are at least two orders of magnitude greater than those at the river-end during the monsoon. Estuarine turbidity maximum (ETM) of nearly similar magnitude occurs at the same location in two periods, interrupted by a period with very low SPM concentrations. The ETM occurring in June–September is associated with low salinities; its formation is attributed to the interactions between strong southwesterly winds (5.1–5.6ms−1) and wind-induced waves and tidal currents and, dominant easterly river flow at the mouth of the estuary. The ETM occurring in February–April is associated with high salinity and is conspicuous. The strong NW and SW winds (3.2–3.7ms−1) and wind-driven waves and currents seem to have acted effectively at the mouth of the estuary in developing turbidity maximum. The impact of sea breeze appears nearly same as that of trade winds and cannot be underestimated in sediment resuspension and deposition.

  1. Wind-driven estuarine turbidity maxima in Mandovi Estuary, central west coast of India

    Kessarkar, Pratima M.; Purnachandra Rao, V.; Shynu, R.; Ahmad, Ishfaq Mir; Mehra, Prakash; Michael, G. S.; Sundar, D.

    2009-08-01

    Systematic studies on the suspended particulate matter (SPM) measured on a seasonal cycle in the Mandovi Estuary, Goa indicate that the average concentrations of SPM at the regular station are ˜20mg/l, 5mg/l, 19mg/l and 5mg/l for June-September, October-January, February-April and May, respectively. SPM exhibits low-to-moderate correlation with rainfall indicating that SPM is also influenced by other processes. Transect stations reveal that the SPM at sea-end stations of the estuary are at least two orders of magnitude greater than those at the river-end during the monsoon. Estuarine turbidity maximum (ETM) of nearly similar magnitude occurs at the same location in two periods, interrupted by a period with very low SPM concentrations. The ETM occurring in June-September is associated with low salinities; its formation is attributed to the interactions between strong southwesterly winds (5.1-5.6ms-1) and wind-induced waves and tidal currents and, dominant easterly river flow at the mouth of the estuary. The ETM occurring in February-April is associated with high salinity and is conspicuous. The strong NW and SW winds (3.2-3.7ms-1) and wind-driven waves and currents seem to have acted effectively at the mouth of the estuary in developing turbidity maximum. The impact of sea breeze appears nearly same as that of trade winds and cannot be underestimated in sediment resuspension and deposition

  2. Mixing in the Amazon estuary

    Bezerra, M. O.

    2010-05-01

    The research area of this work is located at the estuary of the Amazon River (Brazil), near the river mouth. The results of air movement analysis on the surface atmospheric circulation over the Mouth of the Amazonas River, salinity and temperature measures as well as measurements of currents, carried out along a longitudinal section in the navigation canal region of the Northern Bar of the Amazon River (Barra Norte do Rio Amazonas) in June 2006, during the river flood season in the quadrature tide. The dynamics effects affect hydrodynamic,meteorological and hydrographical parameters at the river mouth. The conclusion drawn include that: a) the saline wedge-type stratification can be detected approximately 100km away from the mouth of the Amazon River during the end of the rainy season in the quadrature tide; b) probably, at the Amazon estuary the quadrature entrainment processes are dominant and they are the ones responsible for increased salinity detected in the surface layer, whereas turbulence scattering mixing is not so important. c) The large flow of fresh water from the Amazon River at the end of the rainy season implies the displacement of the saline front position over the internal Amazon continental platform, and d) The tidal wave shows a positive asymmetry in the canal, with floods lasting less than in the ebb tide. This asymmetry decreases towards the ocean, eventually becoming reversed in the presence of a saline wedge. The speeds, however, have a negative asymmetry, with more intense ebb tides, due to the river flow and is more evident by the existence of quadrature tides.

  3. Bar dimensions and bar shapes in estuaries

    Leuven, Jasper; Kleinhans, Maarten; Weisscher, Steven; van der Vegt, Maarten

    2016-04-01

    Estuaries cause fascinating patterns of dynamic channels and shoals. Intertidal sandbars are valuable habitats, whilst channels provide access to harbors. We still lack a full explanation and classification scheme for the shapes and dimensions of bar patterns in natural estuaries, in contrast with bars in rivers. Analytical physics-based models suggest that bar length in estuaries increases with flow velocity, tidal excursion length or estuary width, depending on which model. However, these hypotheses were never validated for lack of data and experiments. We present a large dataset and determine the controls on bar shape and dimensions in estuaries, spanning bar lengths from centimeters (experiments) to 10s of kilometers length. First, we visually identified and classified 190 bars, measured their dimensions (width, length, height) and local braiding index. Data on estuarine geometry and tidal characteristics were obtained from governmental databases and literature on case studies. We found that many complex bars can be seen as simple elongated bars partly cut by mutually evasive ebb- and flood-dominated channels. Data analysis shows that bar dimensions scale with estuary dimensions, in particular estuary width. Breaking up the complex bars in simple bars greatly reduced scatter. Analytical bar theory overpredicts bar dimensions by an order of magnitude in case of small estuarine systems. Likewise, braiding index depends on local width-to-depth ratio, as was previously found for river systems. Our results suggest that estuary dimensions determine the order of magnitude of bar dimensions, while tidal characteristics modify this. We will continue to model bars numerically and experimentally. Our dataset on tidal bars enables future studies on the sedimentary architecture of geologically complex tidal deposits and enables studying effects of man-induced perturbations such as dredging and dumping on bar and channel patterns and habitats.

  4. Carbon dioxide and methane emissions from estuaries

    Abril, G.; Borges, Alberto

    2005-01-01

    Carbon dioxide and methane emissions from estuaries are reviewed in relationwith biogeochemical processes and carbon cycling. In estuaries, carbondioxide and methane emissions show a large spatial and temporalvariability, which results from a complex interaction of river carbon inputs,sedimentation and resuspension processes, microbial processes in watersand sediments, tidal exchanges with marshes and flats and gas exchangewith the atmosphere. The net mineralization of land-derived organic ca...

  5. Tidal Heights in Hyper-Synchronous Estuaries

    Ian M. Kidd; Shuhong Chai; Andrew Fischer

    2014-01-01

    Inconsistencies between datasets are examined with reference to flood tidal elevations in the Tamar River estuary, Tasmania Australia. Errors in a 30-year-old commonly cited dataset have been perpetuated in subsequent publications and datasets, and a clarification is herein provided. Elevation of the flood tidal wave as it propagates the estuary is evident in mean tide level and mean sea level, although the analysis is compromised by the temporal differences of the d...

  6. Benthic foraminifera (Protista) as indicators of metal pollution in areas of historic mining: examples from southwest England

    Hart, Malcolm; Smart, Christopher

    2016-04-01

    Southwest England has been, from Roman times, an important mining area supplying a range of important metals, including copper, tin, tungsten, arsenic, zinc, silver, etc. This mining activity virtually disappeared in the twentieth century, although one tungsten mine near Plymouth has recently re-opened. Large areas of Cornwall and West Devon are now inscribed as the 'Cornish Mining World Heritage Site' on the cultural list of UNESCO. Many of the old mines with their spoil heaps and tailings dams are now protected and, together with the mineral-rich local geology, provide many catchments with on-going metal pollution. In January 1992, after a period of prolonged, heavy rainfall Wheal Jane mine flooded and discharged heavily polluted, acidic, water into Restonguet Creek and the Fal Estuary. This event provided the setting for a detailed investigation of the immediate impact of the pollution and the resulting environmental improvements caused by engineering interventions and natural re-adjustment. Benthic foraminifera disappeared from Restronguet Creek for a number of years and while there is now an abundant, though low diversity, estuarine assemblage of foraminifera living in the creek there are still high levels (data. In other estuarine systems in southwest England, such as the River Fowey and the River Tamar, levels of deformity are less, though still significant for areas no longer being actively mined. This demonstrates that polluted sediments in all these estuaries, which can be disturbed during floods or times of stormy weather, and the background levels of metal elements in the catchments that supply these estuaries, are sufficient to maintain these levels of deformity in the long term. OLUGBODE, O.I., HART, M.B. & STUBBLES, S.J. 2005. Foraminifera from Restronguet Creek: monitoring recovery from the Wheal Jane pollution incident. Geoscience in south-west England, 11, 82-92.

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

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

    coast of India, Tsunami impacts, Water quality Author Version Environ. Monit. Assess.: 125(1-3); 2007; 41-45 Introduction: The great Indian Ocean Tsunami of December 2004 generated due to the Earthquake off the west coast of Sumatra..., for the encouragement and help. We are grateful to ICMAM-PD, Chennai for the financial support provided under the project ?Ecosystem modeling of Cochin backwaters?. We thank Cochin Port Trust, Cochin for providing the automatic tide gauge data. The positive journal...

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

    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. (author)

  9. Évaluation et réduction des impacts écologiques liés à la consommation des ménages : conception méthodologique et application au Pays Cœur Entre-deux-Mers, Gironde, France

    Sennes, V.

    2008-01-01

    The aim of this thesis is to strengthen the conceptual and methodological foundations of ecoresponsible consumption. These notions are then applied to the peri-urban area of the “Pays Cœur Entre-deux-Mers” (Gironde, France) in order to provide the main societal actors with some elements to help them towards a better understanding of ways to promote and evaluate ecoresponsible consumption. This is an exploratory process based on the ecology of the family; it involves a multi-disciplinary appro...

  10. Estuary wader capacity following severe weather mortality

    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)

  11. Trophic characteristics of a mangrove fish community in Southwest Thailand: Important mangrove contribution and intraspecies feeding variability

    Zagars, Matiss; Ikejima, Kou; Kasai, Akihide; Arai, Nobuaki; Tongnunui, Prasert

    2013-03-01

    Mangrove production has been found to make a major contribution to the nutrition of a fish community in the Sikao Creek mangrove estuary, Southwest Thailand. Gut content analysis and carbon and nitrogen stable isotope analysis were used to assess fish feeding behavior and trophic reliance on different primary producers (mangrove leaves, phytoplankton, microphytobenthos) focusing on 19 dominant fish species, and 4 potential fish food items. Cluster analysis identified 5 trophic groups and the IsoSource model indicated the importance of primary food sources in trophically supporting different fish species. Most analyzed fish species had carbon isotopic signatures that were more depleted than those reported in previous studies, and the IsoSource model indicated that mangrove leaves were an important primary food source. This may be a specific characteristic of our study site, which is not well connected to other productive coastal habitats that provide alternative primary food sources. Thus we suggest that food chains in trophically isolated mangrove estuaries of southwest Thailand are more dependent on mangrove tree production. We also assessed the relationship of individuality in fish feeding habits and variability of δ13C values and showed that several mangrove fish species have significant intraspecies variability in feeding habits, possibly due to high intraspecific competition.

  12. 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,...

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

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

  14. PECONIC ESTUARY: AN ASSESSMENT OF SHELLFISH RESOURCES IN THE TRIBUTARIES AND EMBAYMENTS OF THE PECONIC ESTUARY

    Executive Summary Historically, the Peconic Estuary's shellfish resources have supported significant fisheries for a number of species including hard clams, oysters and bay scallops. However, distribution and abundance data for the tributaries and embayments within the Peconic Es...

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

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

    2015-08-01

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

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

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

    2015-08-01

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

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

    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 (<5). Hence, it is suggested that during the periods of fresh water dominance, the trophic 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).

  18. Features at some significant estuaries of India

    Bhattathiri, P.M.A.

    in the second and 162 in the third. Most of the studies on various aspects have been confined to very few of these, and that too, mostly to minor ones. Very little work has been carried out from many of the estuaries of the major rivers. An overview...

  19. Radiological assessment of the Esk Estuary

    An assessment has been carried out of the radiological impact of artificial radionuclides in the Esk estuary in Cumbria, UK. Measurements were made of the distributions of 137Cs, 239+240Pu, and 241Am in water, surface bed sediments and core profiles. The highest measured concentrations in surface sediments were 2.8 Bq g-1 of 137Cs, 3.1 Bq g-1 of 239+240Pu and 4.7 Bq g-1 of 241Am. These values represent significant decreases from similar measurements made in 1970-1980. The measured behaviour of the actinides in low salinity water at the head of the estuary supports previous observations of actinide remobilisation from the bed. A model has been developed which simulates the long-term behaviour of radioactivity in the estuary. The model incorporates representations of tidal mixing, sediment transport, seasonal and long-term sediment accretion. The model also represents long-term build-up in salt marsh regions. The model gives good agreement with measured distributions of 137Cs, but tends to underestimate actinide concentrations by factors of 2-3. Dose calculations show the importance of radionuclide uptake through livestock grazing sea-washed pasture alongside the estuary. 137Cs and 241Am are identified as the most important radionuclides considered in the assessment. (Author)

  20. Bacterioplankton dynamics in the Mondego estuary (Portugal)

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

    2003-05-01

    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 less by the spatial structure of the estuary. Three main metabolic groups of bacterioplankton—aerobic heterotrophic bacteria, sulphate-reducing bacteria (SRB) and nitrate-reducing bacteria (NRB)—involved in the cycling of organic matter, were present in the water column of the estuary. Their relative abundance depended on the particular physical, chemical and biological environment. The abundance of aerobic heterotrophic bacteria, during the 11 month study, was modelled as a function of nitrate (the most important variable, with a negative effect), temperature, salinity and pH (with positive effects). SRB appeared to be limited to the water-sediment interface, where concentrations of sulphate and POM were greater. A competition between SRB and NRB for carbon has also been suggested.

  1. Reversing circulation patterns in a tropical estuary

    Valle-Levinson, Arnoldo; Bosley, Kathryn T.

    2003-10-01

    A combination of current velocity and water density measurements was used to characterize the basic patterns of water exchange in the Gulf of Fonseca, a tropical estuary on the Pacific Ocean side of Central America. The measurements were obtained during spring and neap tides in March (dry season) and June (wet season) of 2001 and consisted of profiles of current velocity and density along four transects. From mid-March to mid-April a time series of hourly surface current velocity maps was also obtained with a high-frequency radar system of two antennas. The sampling transects and the radar coverage concentrated in the portion of the estuary that has open communication with the ocean. During the dry season, water exchange at the entrance to the gulf suggested an inverse estuarine circulation that was more robust, and its dynamics were closer to geostrophy during neap than during spring tides. It is likely that salinity increased toward the tributaries of the system and then decreased within those tributaries because of the persistent influence of fresh water. In contrast, during the wet season, salinity decreased into the estuary, and the circulation resembled that of a typical estuary. In this season the fortnightly modulation of exchange flows was masked by wind effects, which also played a relevant role in the dynamics. The net volume inflows measured in both seasons suggested that the residence time of the Gulf of Fonseca varies from 2 weeks to 1 month.

  2. BCG Approaches for Improved Management of Estuaries

    Estuaries and other complex aquatic systems are exposed to a variety of stressors that act at several scales, but are managed piecemeal - - often resulting in a “death by 1000 cuts” caused by cumulative impacts to these valued resources. To address this, managers need tools that...

  3. Distribution of foraminifera in the Cochin estuary

    Rao, K.K.; Balasubramanian, T.

    of the channel by dredging. It is also predicted that total number of species present in the estuary will likely increase further as more nearshore foraminiferids migrate into it in the coming years, with more deepening of the channel as it will enhance speed...

  4. Nutrient elements in large Chinese estuaries

    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.

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

    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)

  6. Nutrient budgets for large Chinese estuaries

    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

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

    Chen, XinJian

    2012-06-01

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

  8. Mesozooplankton affinities in a recovering freshwater estuary

    Chambord, Sophie; Maris, Tom; Colas, Fanny; Van Engeland, Tom; Sossou, Akoko-C.; Azémar, Frédéric; Le Coz, Maïwen; Cox, Tom; Buisson, Laetitia; Souissi, Sami; Meire, Patrick; Tackx, Michèle

    2016-08-01

    Water quality of the Scheldt estuary (Belgium/The Netherlands) has considerably improved in recent years, especially in the upstream, freshwater reaches. Within the zooplankton community, the copepod Eurytemora affinis, typically abundant in brackish water and quasi-absent from freshwater before 2007, has since substantially developed in the latter, where it now represents 90% of the crustacean mesozooplankton community. Simultaneously, cyclopoid copepod abundance has greatly decreased, while cladoceran abundance did not change. The study aim was: 1) to verify if the zooplankton community described for the period 2007-2009 by Mialet et al. (2011) has stabilized until present, and 2) to look for the environmental conditions favouring E. affinis development and causing changes in the upstream freshwater zooplankton community. The 2002-2012 temporal evolution of the zooplankton distribution at three stations in the upstream freshwater Scheldt estuary was analyzed. Water quality remained better after 2007 than before, and some factors revealed continuous improvement in annual mean concentrations (e.g. increase in O2, decrease in BOD5 and NH4sbnd N concentration). The increase in oxygen and the decrease in NH4sbnd N concentration, together with low discharge during summer were the main environmental factors explaining the development and timing of E. affinis in the upstream freshwater reach. In this reach, E. affinis maximal abundance is shifted to higher temperatures (summer) compared to its typical maximum spring abundance peak in the brackish zone of the Scheldt estuary and in most temperate estuaries. The changes in zooplankton community followed a temporal and spatial gradient induced by the spatio-temporal evolution of water quality improvement. The most downstream station (3) allowed E. affinis development (oxygen concentration > 4 mg L-1; NH4sbnd N concentration oxygen, etc.), there is no clear cause for their decline. Water quality improvement in the freshwater

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

    Shivaprasad, A.; Vinita, J.; Revichandran, C.; Reny, P. D.; Deepak, M. P.; Muraleedharan, K. R.; Naveen Kumar, K. R.

    2013-01-01

    The intratidal, spring-neap and seasonal variations in stratification were examined in the 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 the Cochin estuary. For the seasonally varying river flow in the estuary, salt intrusion receded with increasing river flow in monsoon and rebounded with decreasing river flow in dry season. 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 the Cochin estuary.

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

    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.

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

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

    2015-10-01

    Understanding the way 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 study the salt intrusion pattern under different tide and fresh water discharge conditions.

  12. Fundamentals of conservation in the Southwest

    Leopold, A.

    The author discusses mineral and organic wealth in the Southwest as an economic resource. Their value is affected more or less by that idea or method of development broadly called conservation. With the exception of coal, the mineral wealth of the southwest, from the standpoint of an economic foundation for society, is exhaustible. The coal available in the area will probably always be handicapped by long hauls and the absence of water. The organic resources, mainly farms, ranges, forests, waters, and water powers, are in a rundown condition. The author concludes that the deterioration of the fundamental resources - land and water - is in the nature of permanent destruction; the process is also seen to be cumulative and gaining in momentum every year. To explore the deterioration, the author discusses the climate and the delicate balance of the fragile ecosystem of the southwest. He concludes the analysis with a discussion of the moral issues involved, specifically the morality of conservation. (SAC)

  13. SOUTHWEST REGIONAL PARTNERSHIP ON CARBON SEQUESTRATION

    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.

  14. The ecological condition of estuaries in the Gulf of Mexico

    1999-01-01

    This document is intended for use by scientists and other citizens concerned with the ecological condition of estuaries, as well as by managers and lawmakers interested in the sustained use of estuaries for commercial and recreational purposes. It also addresses public concerns about the aesthetic quality of coastal areas vital to tourism and recreation. By producing this report on the ecological condition of estuaries in the Gulf of Mexico, we have taken one step in assessing the health of t...

  15. Marine geology of the St. Lawrence Estuary

    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.

  16. Time-dependence of salinity in monsoonal estuaries

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

    ) Based on data during 1970- 1979 Ria of Ferrol, Spain (north-east coast) 250 14.5 6.0 de Castro et al. (2004) Based on data during 1970- 1982 Hudson River estuary, U.S.A. (east coast) 1925* 877.3 376.7 Ralston et al. (2008), Moran and Limburg (1986.... We refer to such estuaries as “monsoonal estuaries” following earlier usage (see, for example, 3 Khadkikar, 2008). To make a case for essential unsteadiness of the salinity field in a monsoonal estuary, we use the Mandovi estuary on the west...

  17. Phosphorous dynamics in a temperate intertidal estuary

    Lillebø, A. I.; Neto, J. M.; Flindt, M. R.; Marques, J C; Pardal, M.A.

    2004-01-01

    Conservation and management of aquatic systems require detailed information of the processes that affect their functioning and development. The objectives of the present work were to describe the phosphorus dynamics during a complete tidal cycle and to quantify the relative contribution of the most common estuarine areas (e.g. seagrass beds, salt marshes, mud- and sand-flats without vegetation) to phosphorus net internal loading in a temperate intertidal estuary.

  18. Columbia River Estuary Ecosystem Classification Cultural Features

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

    2012-01-01

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

  19. 2005 Southwest Florida Water Management District (SWFWMD) Lidar: 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...

  20. Current Characterization at the Amazon estuary

    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

  1. Nitrogen Source and Loading Data for EPA Estuary Data Mapper

    Nitrogen source and loading data have been compiled and aggregated at the scale of estuaries and associated watersheds of the conterminous United States, using the spatial framework in EPA's Estuary Data Mapper (EDM) to provide system boundaries. Original sources of data include...

  2. A note on salt intrusion in funnel-shaped estuaries: Application to the Incomati estuary, Mozambique

    Brockway, Rachel; Bowers, David; Hoguane, Antonio; Dove, Veronica; Vassele, Valentina

    2006-01-01

    Salt intrusion in estuaries is important for ecological reasons as well as water extraction purposes. The distance salt intrudes upstream depends on a number of factors, including river discharge, tidal and wind mixing and gravitational circulation. In this paper, an analytical solution is presented for the salt intrusion in a well mixed, funnel-shaped estuary whose cross sectional area decreases exponentially (with decay coefficient β) with distance, x, inland, and in which longitudinal mixing is constant along the length of the estuary. The solution predicts that a graph of the logarithm of salinity against exp ( βx) should be a straight line, with slope proportional to the mixing coefficient K x. The solution is tested against observations from 15 surveys over a four-year period in the Incomati estuary. Good straight line fits, as predicted, are observed on all surveys, with a mean R2 = 0.97. The average value of K x for all surveys is 38 m 2 s -1. The solution is used to make predictions about the minimum river flow required to prevent salt intruding to an extent where it causes a detrimental effect on water extraction. The minimum recommended river flow required to prevent this is 35 m 3 s -1. In recent years, flow has fallen below this level for several months each year.

  3. Greenhouse gas (N2O emission from Portuguese estuaries

    Célia Gonçalves

    2014-07-01

    Tagus, Minho and Lima estuaries are source of N2O to the atmosphere. Particularly, in Lima estuary anthropogenic N input seems to play an important role on N2O emission. However, in a global perspective N2O attained emissions represent a reduced fraction (2O yr-1, Barnes and Upstill-Goddard, 2011. Values are comparable with those registered in some Portuguese estuaries and other European less eutrophic estuaries. However, it is known that higher N2O emissions in estuaries may occur during winter and spring (Sun et al., 2014. Thus, these systems may represent on an annual basis a larger source of N2O, which can only be clarified in future studies. Only a full comprehension of the global estuarine nitrogen cycle will provide an efficient basis of scientific knowledge for sustainably management of such ecosystems and ultimately reduce N2O emissions.

  4. Southwest Regional Partnership on Carbon Sequestration

    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

  5. Algae and water pollution in Mahi Estuary

    Jiyalal Ram, M.

    1991-01-01

    Distribution of phytoplankton, chlorophyll A and phaeophytin was studied at different locations in the Mahi Estuary, Gujarat, India during 1982. The water quality at the discharge point was poor while the region away from it was relatively unpolluted. The results indicated a wide range of variation in phytoplankton population (7.68-5010, 96 x 10 super(4) cells/l, chl. a 2.22-58.22 mg/m super(3) and phaeophytin [0.20-10.21 mg/m super(3)]. The ratio of chl. a/phaeophytin were remarkably low at ...

  6. SOUTHWEST REGIONAL PARTNERSHIP FOR CARBON SEQUESTRATION

    Brian McPherson

    2004-04-01

    The Southwest Partnership Region includes five states (Arizona, Colorado, New Mexico, Oklahoma, Utah) and contiguous areas from three adjacent states (west Texas, south Wyoming, and west Kansas). This energy-rich region exhibits some of the largest growth rates in the nation, and it contains two major CO{sub 2} pipeline networks that presently tap natural subsurface CO{sub 2} reservoirs for enhanced oil recovery at a rate of 30 million tons per year. The ten largest coal-fired power plants in the region produce 50% (140 million tons CO{sub 2}/y) of the total CO{sub 2} from power-plant fossil fuel combustion, with power plant emissions close to half the total CO{sub 2} emissions. 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, the five major electric utility industries, seven oil, gas and coal companies, three federal agencies, the Navajo Nation, several NGOs including the Western Governors Association, and data sharing agreements with four other surrounding states. The Partnership is developing action plans for possible Phase II carbon sequestration pilot tests in the region, as well as the non-technical aspects necessary for developing and carrying out these pilot tests. The establishment of a website network to facilitate data storage and information sharing, decision-making, and future management of carbon sequestration in the region is a priority. The Southwest Partnership's approach includes (1) dissemination of existing regulatory/permitting requirements, (2) assessing and initiating public acceptance of possible sequestration approaches, and (3) evaluation and ranking of the most appropriate sequestration technologies for capture and storage of CO{sub 2} in the Southwest Region. The Partnership will also identify potential

  7. Impressions from South-West Uganda

    Hardouin, J.

    1987-01-01

    Certain features of the prevailing agricultural and livestock management practices in four districts of the South-West Uganda are briefly described. This area is characterized by rather high elevation, good rainfall, fertile soil and hills with steep slopes and mountains in some parts. In three ofthe four districts land is becoming scarce though agricultural production is high but traditional. Cash and food crop production are prevalent ; the staple food being plantain banana and milk product...

  8. Mercury distribution in Douro estuary (Portugal)

    Determinations of dissolved reactive and total dissolved mercury, particulate and sedimentary mercury, dissolved organic carbon (DOC), particulate organic carbon (POC) and suspended particulate matter (SPM) have been made in the estuary of river Douro, in northern Portugal. The estuary was stratified by salinity along most of its length, it had low concentrations of SPM, typically -3, and concentrations of DOC in the range -3. The surface waters had a maximum dissolved concentration of reactive mercury of about 10 ng dm-3, whereas for the more saline bottom waters it was about 65 ng dm-3. The surface waters had maximum concentrations of total suspended particulate mercury of ∼7 μg g-1 and the bottom waters were always -1. Concentrations of mercury in sediments was low and in the range from 0.06 to 0.18 μg g-1. The transport of mercury in surface waters was mainly associated with organic-rich particulate matter, while in bottom waters the dissolved phase transport of mercury is more important. Lower particulate organic matter, formation of chlorocomplexes in more saline waters and eventually the presence of colloids appear to explain the difference of mercury partitioning in Douro estuarine waters

  9. Study of Bed Friction Factor for the Wu River Estuary

    Chin-Wu LAN; Cyuan-Chen LEE

    2006-01-01

    In this research the bed friction effect is estimated of a river estuary by use of hydrodynamic analysis. The on-site sampled data of the Wu River estuary is applied to the analysis. There are many dynamic factors that affect the flow characteristics in the estuary. The effect of tide on the generation of tidal current, bottom friction and geometry effect is the focus of this paper. The Wu River estuary is about 15 km in length, with a small bottom slope and no physical obstruction; thus the incident wave at the estuary is considered a progressive wave with damping effect. The amplitude reduction and phase shift of the incident wave are analyzed. By the analysis of celerity reduction factor of the estuary, the estimated value of mean resistance coefficient M(μ,κ), damping modulus μ, and wave number κ for the sections at observation stations can be determined. Furthermore, data gathered from on-site observations are applied for validation. Finally, Manning's coefficient for each section of the observation stations can be determined. It is found that the value of Manning's coefficient is small downstream and increases towards upstream, and that the bed friction effect of an estuary varies largely. The estimated results of the paper are compared with the empirical formulas and the modified solution for practical application is discussed.

  10. Temporal Variability of Nutrient Budgets in a Tropical River Estuary

    Thanomsak Boonphakdee

    2008-01-01

    Full Text Available Water, salt, dissolved inorganic nitrogen (DIN, and dissolved inorganic phosphorus (DIP budgets in the Bangpakong Estuary were conducted by repeated observations and multiple box modeling. Water samples for inorganic nutrient analyses were collected monthly from June 2000 to May 2001. Flushing time at the estuary depicts high variations ranging from 1.4 (October 2000 to 80 days (February 2001 with an annual mean of 15.2 days. Seasonal variation in salinity gradients and estuarine Richardson numbers show the Bangpakong Estuary was partially stratified during the wet season and a well-mixed estuary in the dry season. Riverine nutrient inputs and distributions of nutrient concentrations within the river estuary varied in space and time. Temporal variations in fluxes were strong within inter-seasonal scales owing to water fluxes and system concentrations. The increase of DIN and DIP fluxes in the estuary may be the results of degradation of particulate organic matter. The Bangpakong Estuary appears to be a heterotrophic system where respiration exceeds photosynthesis (p-r < 0 and a denitrifying system. Seasonal variations in biogeochemical rates were attributable to differences in magnitude of freshwater inputs.

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

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

    2004-01-01

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

  12. Mass and salt transfers and halocline depths in an estuary

    LONG, ROBERT R.

    2011-01-01

    The paper considers fluxes of brackish and ocean water out of and into an estuary as well as the depth of the halocline in the estuary. The discussion ignores the details of the mass distribution and circulations in the main body of the estuary (except for the halocline depth) and concentrates on determining the flow conditions and interface depths in the vicinity of the mouth. The flow there is considered to be frictionless and the pressure hydrostatic, and the first part of the analysis, wh...

  13. Oysters return to the Tagus estuary through an ecological model

    Bento, Vânia Sofia de Oliveira

    2008-01-01

    Aquaculture is an activity that has been increasing along the last years. Until the 1970’s Portugal and more specifically the Tagus estuary, was the major exporter of oysters in Europe. Factors like TBT and oysters gill disease had made that the shellfish aquaculture has never been again practised in Tagus estuary. According to that, this work intends to concept and to implement an ecological model that develops the oysters growth in order to them return to the estuary. To begin with, the ...

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

    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)

  15. 2012 Southwest Florida Water Management District (SWFWMD) 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...

  16. Fluxes of nitrogen in Chaliyar River Estuary, India

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

    contribution of external nutrient supply, nutrient budget, geo-chemical and biochemical pathways . The major source of nitrogen in the estuary is the river discharge. During pre-monsoon period, the percentage of inorganic nitrogen to total nitrogen pool...

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

    US Fish and Wildlife Service, Department of the Interior — A chlor-alkali plant in Brunswick, Ga, discharged >2 kg mercury/day into a tributary of the Turtle River-Brunswick Estuary from 1966 to 1971. Mercury...

  18. The application of Yangtze Estuary Tidal Wetlands Geographic Information System

    WANGJun; CHENZhenlou; XUShiyuan; WANGDongqi; LIUJie

    2005-01-01

    Yangtze Estuary Tidal Wetlands Geographic Information System (YETWGIS) is a comprehensive software system for environmental management and decision of Yangtze estuary tidal wetlands. Based on MapObjects components technology, Data Mining technology, mathematical modeling method and Visual Basic language, this software system has many functions such as displaying, editing, querying and searching, spatial statistics and analysis, thematic map compiling, and environmental quality evaluation. This paper firstly outlined the system structure, key techniques, and achieving methods of YETWGIS, and then, described the core modules (the thematic map compiling module and environmental quality evaluation model module) in detail. In addition, based on information entropy model, it thoroughly discussed the methods of environmental quality evaluation and indicators' weight calculation. Finally, by using YETWGIS, this paper analyzed the spatial distribution characteristics of Heavy Metal and Persistent Organic Pollutants (POPs) of the Yangtze estuary tidal wetlands in 2002, and evaluated the environmental quality of the Yangtze estuary tidal wetlands in 2003.

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

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

    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...

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

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

  1. MODIS water quality algorithms for northwest Florida estuaries

    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...

  2. Primary productivity in Mandovi-Zuari estuaries in Goa

    KrishnaKumari, L.; Bhattathiri, P.M.A.; Matondkar, S.G.P.; John

    -1 Primary productivity in Mandovi-Zuari estuaries in Goa L. Krishna Kumari, P. M. A. Bhattathiri, S.G.P. Matondkar and Julie John National Institute of Oceanography, Dona Paula, Goa - 403 004, India Abstract Measurement on primary production...

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

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

    phosphorous to the ocean and dissolved inorganic carbon to the atmosphere (Smith and Hollibaugh 1993; Sarma et al. 2001). Our studies suggest that the persistence of net auto- trophy during the nonmonsoon in estuaries could have re- sulted in production...

  4. Evaluating Causes of Ecological Impairments in the Estuaries of Ukraine

    Ukrainian estuaries have not undergone a systematic evaluation of the causes of ecological impairments caused by anthropogenic contamination. The objective of this evaluation is to use recently developed diagnostic tools to determine the causes of benthic ecological impairments. ...

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

    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.

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

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

    the region among the impacted estuaries in the world. Accumulation of metals in this estuarine system is aggravated by the weak flushing. These pressures are deemed inevitable with growth initiated in the harbour and associated with mega city development...

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

    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

  8. UNAVCO-PBO Southwest Region Network Operations

    Walls, C. P.; Mann, D.; Basset, A.; Sklar, J.; Jarvis, C.; Pitcher, T.; Lawrence, S.; Greathouse, M.; Feaux, K.

    2012-12-01

    The UNAVCO Southwest region of the Plate Boundary Observatory manages 470 continuously operating GPS stations located principally along the transform system of the San Andreas Fault, Eastern California Shear Zone and the northern Baja peninsula. In the past year, network uptime averaged 98% with greater than 99% data acquisition. Communications range from CDMA modem (314), radio (100), Vsat (30), DSL/T1/other (25) to manual download (1). Thirty-four stations have WXT520 metpacks. Sixty-four stations stream 1 Hz data over the VRS3Net typically with cabling, power systems and enclosures. In 2012 the Nucleus upgrade project was completed.

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

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

    . Biogeochemical aspects of Indian estuaries have been mostly studied concerning nutrient dynamics (Mukhopadhyay et al., 2006; Sarma et al., 2010), inorganic and organic carbon biogeochemistry and trace gases(Bouillon et al., 2003; Bouillon et al., 2000; Sarma... of nutrients in Godavari estuary by Sarma et al.(2010).They observed that significant amount of nutrients (>80 µM of dissolved inorganic nitrogen (DIN) and >12 µM of dissolved inorganic phosphate (DIP)) were associated with peak discharge. However, during...

  10. Biota and abiotic environment in the Westerschelde estuary

    Heip, C. H. R.

    1988-01-01

    An estuary such as the Westerschelde is a highly dynamic environment, both on an ecological time scale where climatic and hydrodynamic forces, mainly the tides, shape a very variable environment and on a geological, evolutionary time scale, since estuaries are young and very unstable habitats. Low species diversity and high adaptability of the resident animal and plant populations are characteristic of estuarine habitats where large fluctuations in submersion, salinity, temperature etc. occur...

  11. Functional diversity of fish in estuaries at a global extent

    Rita P. Vasconcelos; Sébastien Villéger; François Guilhaumon

    2015-01-01

    Biodiversity is currently viewed as a framework encompassing multiple facets of the variety of life, including taxonomic and functional aspects. Species richness and composition of fish assemblages in estuaries is defined by global to local processes acting on community colonization. The present study further investigates how biodiversity of fish assemblages varies among estuaries globally, by simultaneously analysing taxonomic and functional richness and diversity of assemblages. A comprehen...

  12. Biological effects of anthropogenic contaminants in the San Francisco Estuary

    Thompson, B.; Adelsbach, T.; Brown, C.; Hunt, J.; Kuwabara, J.; Neale, J.; Ohlendorf, H.; Schwarzbach, S.; Spies, R.; Taberski, K.

    2007-01-01

    Concentrations of many anthropogenic contaminants in the San Francisco Estuary exist at levels that have been associated with biological effects elsewhere, so there is a potential for them to cause biological effects in the Estuary. The purpose of this paper is to summarize information about biological effects on the Estuary's plankton, benthos, fish, birds, and mammals, gathered since the early 1990s, focusing on key accomplishments. These studies have been conducted at all levels of biological organization (sub-cellular through communities), but have included only a small fraction of the organisms and contaminants of concern in the region. The studies summarized provide a body of evidence that some contaminants are causing biological impacts in some biological resources in the Estuary. However, no general patterns of effects were apparent in space and time, and no single contaminant was consistently related to effects among the biota considered. These conclusions reflect the difficulty in demonstrating biological effects due specifically to contamination because there is a wide range of sensitivity to contaminants among the Estuary's many organisms. Additionally, the spatial and temporal distribution of contamination in the Estuary is highly variable, and levels of contamination covary with other environmental factors, such as freshwater inflow or sediment-type. Federal and State regulatory agencies desire to develop biological criteria to protect the Estuary's biological resources. Future studies of biological effects in San Francisco Estuary should focus on the development of meaningful indicators of biological effects, and on key organism and contaminants of concern in long-term, multifaceted studies that include laboratory and field experiments to determine cause and effect to adequately inform management and regulatory decisions. ?? 2006 Elsevier Inc. All rights reserved.

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

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

    IN COCHIN ESTUARY 309 as well as the calculated results of Van der Burge models show great correlation between river discharge and salinity intrusion length (Table 1). Two counteracting effects determine the effect of tidal amplitude. Large tidal... since salinity incursion was not strong enough to completely mask the effect of fresh water flow. During the pre-monsoon, the river discharge is minimum and seawater influence is maximum upstream, the estuary is well-mixed and homogeneity exists...

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

    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

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

    Villa, M., E-mail: mvilla@us.es [Centro de Investigacion, Tecnologia e Innovacion, Universidad de Sevilla CITIUS, Av. Reina Mercedes 4B, E41012-Sevilla (Spain); Mosqueda, F. [Dpto. de Fisica Aplicada, Facultad de Ciencias Experimentales, Universidad de Huelva, Campus de El Carmen, 21007-Huelva (Spain); Hurtado, S. [Centro de Investigacion, Tecnologia e Innovacion, Universidad de Sevilla CITIUS, Av. Reina Mercedes 4B, E41012-Sevilla (Spain); Mantero, J.; Manjon, G. [E. T. S. Arquitectura, Universidad de Sevilla, Departamento de Fisica Aplicada II, Av. Reina Mercedes, 2. 41012-Sevilla (Spain); Perianez, R. [E.U.I.T.A., Universidad de Sevilla, Departamento de Fisica Aplicada III, Carretera de Utrera, Km. 1, 41013 Sevilla (Spain); Vaca, F. [Dpto. de Fisica Aplicada, Facultad de Ciencias Experimentales, Universidad de Huelva, Campus de El Carmen, 21007-Huelva (Spain); Garcia-Tenorio, R. [E. T. S. Arquitectura, Universidad de Sevilla, Departamento de Fisica Aplicada II, Av. Reina Mercedes, 2. 41012-Sevilla (Spain)

    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 {sup 226}Ra and {sup 210}Pb 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 {sup 210}Pb and {sup 226}Ra 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 {sup 226}Ra and {sup 210}Pb 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

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

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

    In May of 2007, a study was initiated by the National Institute of Oceanography (NIO), Goa, India, to investigate the influence of monsoonal rainfall on hydrographic conditions in the Mandovi River of India. The study was undertaken at a location...

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

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

    , the simulated currents are compared with currents measured using RCM9 current meter deployed 2 m below the surface at Bolghatty (Fig.3). The magnitude as well as directions of both measured and simulated currents show a very good match (RMS = 0.068 ms -1 ; VE...

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

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

    2009-07-01

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

  19. Sources, Ages, and Alteration of Organic Matter in Estuaries

    Canuel, Elizabeth A.; Hardison, Amber K.

    2016-01-01

    Understanding the processes influencing the sources and fate of organic matter (OM) in estuaries is important for quantifying the contributions of carbon from land and rivers to the global carbon budget of the coastal ocean. Estuaries are sites of high OM production and processing, and understanding biogeochemical processes within these regions is key to quantifying organic carbon (Corg) budgets at the land-ocean margin. These regions provide vital ecological services, including nutrient filtration and protection from floods and storm surge, and provide habitat and nursery areas for numerous commercially important species. Human activities have modified estuarine systems over time, resulting in changes in the production, respiration, burial, and export of Corg. Corg in estuaries is derived from aquatic, terrigenous, and anthropogenic sources, with each source exhibiting a spectrum of ages and lability. The complex source and age characteristics of Corg in estuaries complicate our ability to trace OM along the river-estuary-coastal ocean continuum. This review focuses on the application of organic biomarkers and compound-specific isotope analyses to estuarine environments and on how these tools have enhanced our ability to discern natural sources of OM, trace their incorporation into food webs, and enhance understanding of the fate of Corg within estuaries and their adjacent waters.

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

    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)

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

    Geddada Mohan NARASIMHA RAO

    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.

  2. Earthquake-triggered landslides in southwest China

    X. L. Chen

    2012-02-01

    Full Text Available Southwest China is located in the southeastern margin of the Tibetan Plateau and it is a region of high seismic activity. Historically, strong earthquakes that occurred here usually generated lots of landslides and brought destructive damages. This paper introduces several earthquake-triggered landslide events in this region and describes their characteristics. Also, the historical data of earthquakes with a magnitude of 7.0 or greater, having occurred in this region, is collected and the relationship between the affected area of landslides and earthquake magnitude is analysed. Based on the study, it can be concluded that strong earthquakes, steep topography as well as fragile geological environment, are the main reasons responsible for serious landslides in southwest China. At the same time, it is found that the relationship between the area affected by landslides and the earthquake magnitude in this region are consistent with what has been obtained worldwide. Moreover, in this paper, it is seen that the size of the areas affected by landslides change enormously even under the same earthquake magnitude in the study region. While at the same tectonic place or fault belt, areas affected by landslides presented similar outline and size. This means that local geological conditions and historical earthquake background have an important influence on landslides distribution, and they should be considered when assessing earthquake-triggered landslide hazards at Grade 1 according to ISSMGE.

  3. Agricultural Cooperation and Horticultural Produce Marketing in Southwest Virginia

    Trupo, Paul

    1997-01-01

    AGRICULTURAL COOPERATION AND HORTICULTURAL PRODUCE MARKETING IN SOUTHWEST VIRGINIA by Paul S. Trupo George W. Norton and Dixie Watts-Reaves, Co-chair Agricultural and Applied Economics (ABSTRACT) Agricultural production in Southwest Virginia is characterized by numerous small, geographically disperse farms dedicated to traditional practices of producing tobacco and cattle. Community leaders have expressed the desire to diversify the region's agricultural production ba...

  4. 7 CFR 1126.2 - Southwest marketing area.

    2010-01-01

    ... 7 Agriculture 9 2010-01-01 2009-01-01 true Southwest marketing area. 1126.2 Section 1126.2 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Milk), DEPARTMENT OF AGRICULTURE MILK IN THE SOUTHWEST MARKETING AREA Order...

  5. Columbia River Estuary Ecosystem Classification Ecosystem Complex

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

    2012-01-01

    Estuarine ecosystems are controlled by a variety of processes that operate at multiple spatial and temporal scales. Understanding the hierarchical nature of these processes will aid in prioritization of restoration efforts. This hierarchical Columbia River Estuary Ecosystem Classification (henceforth "Classification") of the Columbia River estuary is a spatial database of the tidally-influenced reaches of the lower Columbia River, the tidally affected parts of its tributaries, and the landforms that make up their floodplains for the 230 kilometers between the Pacific Ocean and Bonneville Dam. This work is a collaborative effort between University of Washington School of Aquatic and Fishery Sciences (henceforth "UW"), U.S. Geological Survey (henceforth "USGS"), and the Lower Columbia Estuary Partnership (henceforth "EP"). Consideration of geomorphologic processes will improve the understanding of controlling physical factors that drive ecosystem evolution along the tidal Columbia River. The Classification is organized around six hierarchical levels, progressing from the coarsest, regional scale to the finest, localized scale: (1) Ecosystem Province; (2) Ecoregion; (3) Hydrogeomorphic Reach; (4) Ecosystem Complex; (5) Geomorphic Catena; and (6) Primary Cover Class. For Levels 4 and 5, we mapped landforms within the Holocene floodplain primarily by visual interpretation of Light Detection and Ranging (LiDAR) topography supplemented with aerial photographs, Natural Resources Conservation Service (NRCS) soils data, and historical maps. Mapped landforms are classified as to their current geomorphic function, the inferred process regime that formed them, and anthropogenic modification. Channels were classified primarily by a set of depth-based rules and geometric relationships. Classification Level 5 floodplain landforms ("geomorphic catenae") were further classified based on multivariate analysis of land-cover within the mapped landform area and attributed as "sub

  6. Columbia River Estuary Ecosystem Classification Geomorphic Catena

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

    2012-01-01

    Estuarine ecosystems are controlled by a variety of processes that operate at multiple spatial and temporal scales. Understanding the hierarchical nature of these processes will aid in prioritization of restoration efforts. This hierarchical Columbia River Estuary Ecosystem Classification (henceforth "Classification") of the Columbia River estuary is a spatial database of the tidally-influenced reaches of the lower Columbia River, the tidally affected parts of its tributaries, and the landforms that make up their floodplains for the 230 kilometers between the Pacific Ocean and Bonneville Dam. This work is a collaborative effort between University of Washington School of Aquatic and Fishery Sciences (henceforth "UW"), U.S. Geological Survey (henceforth "USGS"), and the Lower Columbia Estuary Partnership (henceforth "EP"). Consideration of geomorphologic processes will improve the understanding of controlling physical factors that drive ecosystem evolution along the tidal Columbia River. The Classification is organized around six hierarchical levels, progressing from the coarsest, regional scale to the finest, localized scale: (1) Ecosystem Province; (2) Ecoregion; (3) Hydrogeomorphic Reach; (4) Ecosystem Complex; (5) Geomorphic Catena; and (6) Primary Cover Class. For Levels 4 and 5, we mapped landforms within the Holocene floodplain primarily by visual interpretation of Light Detection and Ranging (LiDAR) topography supplemented with aerial photographs, Natural Resources Conservation Service (NRCS) soils data, and historical maps. Mapped landforms are classified as to their current geomorphic function, the inferred process regime that formed them, and anthropogenic modification. Channels were classified primarily by a set of depth-based rules and geometric relationships. Classification Level 5 floodplain landforms ("geomorphic catenae") were further classified based on multivariate analysis of land-cover within the mapped landform area and attributed as "sub

  7. Columbia River Estuary Ecosystem Classification Hydrogeomorphic Reach

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

    2012-01-01

    Estuarine ecosystems are controlled by a variety of processes that operate at multiple spatial and temporal scales. Understanding the hierarchical nature of these processes will aid in prioritization of restoration efforts. This hierarchical Columbia River Estuary Ecosystem Classification (henceforth "Classification") of the Columbia River estuary is a spatial database of the tidally-influenced reaches of the lower Columbia River, the tidally affected parts of its tributaries, and the landforms that make up their floodplains for the 230 kilometers between the Pacific Ocean and Bonneville Dam. This work is a collaborative effort between University of Washington School of Aquatic and Fishery Sciences (henceforth "UW"), U.S. Geological Survey (henceforth "USGS"), and the Lower Columbia Estuary Partnership (henceforth "EP"). Consideration of geomorphologic processes will improve the understanding of controlling physical factors that drive ecosystem evolution along the tidal Columbia River. The Classification is organized around six hierarchical levels, progressing from the coarsest, regional scale to the finest, localized scale: (1) Ecosystem Province; (2) Ecoregion; (3) Hydrogeomorphic Reach; (4) Ecosystem Complex; (5) Geomorphic Catena; and (6) Primary Cover Class. For Levels 4 and 5, we mapped landforms within the Holocene floodplain primarily by visual interpretation of Light Detection and Ranging (LiDAR) topography supplemented with aerial photographs, Natural Resources Conservation Service (NRCS) soils data, and historical maps. Mapped landforms are classified as to their current geomorphic function, the inferred process regime that formed them, and anthropogenic modification. Channels were classified primarily by a set of depth-based rules and geometric relationships. Classification Level 5 floodplain landforms ("geomorphic catenae") were further classified based on multivariate analysis of land-cover within the mapped landform area and attributed as "sub

  8. THE CHARACTERISTIC OF MARINE ENVIRONMENT IN LINGDINGYANG ESTUARY

    CHEN; Bing-lu

    2001-01-01

    [1]LIN Zhi-qing, 1985. The Nutrient salts in the water between Guangzhou and Humen [J] . Tropical Oceanography, 4(2):52-59. (in Chinese)[2]LUO Zhang-ren, YING Zhi-pu et al., 1992. The Harbours in South China[M]. Guangzhou: Zhongshan University Press,101-126. (in Chinese)[3]PENG Yun-hui et al., 1991. The relationship of phosphate and dissolved oxygen in Pearl River Estuary [J]. Marine Report,10(6): 25-29. (in Chinese)[4]PENG Yun-hui et al., 1994. The relationship of dissolved oxygen and nutrient salts in Pearl River Estuary[J]. Tropical Oceanography, 13(1): 96-100. (in Chinese)[5]TAN Wei-guang et al., 1993. Assessment of eutrophication of Pearl River Estuary [J] . Research & Exploration of Nanhai, (2): 17-21. (in Chinese)[6]TANG Yong-Luan, 1984. The Characteristic of the dispersion model of the substances of Pearl River Estuary and Lingding Estuary [J] . Marine Environmental Science, 3(3): 1-11.(in Chinese)[7]ZHOU Yan-xia, 1994. Analysis of the water quality of Pearl River Estuary and neighboring sea area [J]. Marine Report, 13(3):24-30. (in Chinese)[8]ZHAO Huan-ting, 1981. The topograghy of Lingding Estuary [J]. Journal of Oceanography, 3(2): 20-27. (in Chinese)

  9. Urban microbial ecology of a freshwater estuary of Lake Michigan

    Jenny C. Fisher

    2015-07-01

    Full Text Available Abstract Freshwater estuaries throughout the Great Lakes region receive stormwater runoff and riverine inputs from heavily urbanized population centers. While human and animal feces contained in this runoff are often the focus of source tracking investigations, non-fecal bacterial loads from soil, aerosols, urban infrastructure, and other sources are also transported to estuaries and lakes. We quantified and characterized this non-fecal urban microbial component using bacterial 16S rRNA gene sequences from sewage, stormwater, rivers, harbor/estuary, and the lake surrounding Milwaukee, WI, USA. Bacterial communities from each of these environments had a distinctive composition, but some community members were shared among environments. We used a statistical biomarker discovery tool to identify the components of the microbial community that were most strongly associated with stormwater and sewage to describe an “urban microbial signature,” and measured the presence and relative abundance of these organisms in the rivers, estuary, and lake. This urban signature increased in magnitude in the estuary and harbor with increasing rainfall levels, and was more apparent in lake samples with closest proximity to the Milwaukee estuary. The dominant bacterial taxa in the urban signature were Acinetobacter, Aeromonas, and Pseudomonas, which are organisms associated with pipe infrastructure and soil and not typically found in pelagic freshwater environments. These taxa were highly abundant in stormwater and sewage, but sewage also contained a high abundance of Arcobacter and Trichococcus that appeared in lower abundance in stormwater outfalls and in trace amounts in aquatic environments. Urban signature organisms comprised 1.7% of estuary and harbor communities under baseflow conditions, 3.5% after rain, and >10% after a combined sewer overflow. With predicted increases in urbanization across the Great Lakes, further alteration of freshwater communities is

  10. Biogeography of dinoflagellate cysts in northwest Atlantic estuaries.

    Price, Andrea M; Pospelova, Vera; Coffin, Michael R S; Latimer, James S; Chmura, Gail L

    2016-08-01

    Few biogeographic studies of dinoflagellate cysts include the near-shore estuarine environment. We determine the effect of estuary type, biogeography, and water quality on the spatial distribution of organic-walled dinoflagellate cysts from the Northeast USA (Maine to Delaware) and Canada (Prince Edward Island). A total of 69 surface sediment samples were collected from 27 estuaries, from sites with surface salinities >20. Dinoflagellate cysts were examined microscopically and compared to environmental parameters using multivariate ordination techniques. The spatial distribution of cyst taxa reflects biogeographic provinces established by other marine organisms, with Cape Cod separating the northern Acadian Province from the southern Virginian Province. Species such as Lingulodinium machaerophorum and Polysphaeridinium zoharyi were found almost exclusively in the Virginian Province, while others such as Dubridinium spp. and Islandinium? cezare were more abundant in the Acadian Province. Tidal range, sea surface temperature (SST), and sea surface salinity (SSS) are statistically significant parameters influencing cyst assemblages. Samples from the same type of estuary cluster together in canonical correspondence analysis when the estuaries are within the same biogeographic province. The large geographic extent of this study, encompassing four main estuary types (riverine, lagoon, coastal embayment, and fjord), allowed us to determine that the type of estuary has an important influence on cyst assemblages. Due to greater seasonal variations in SSTs and SSSs in estuaries compared to the open ocean, cyst assemblages show distinct latitudinal trends. The estuarine context is important for understanding present-day species distribution, the factors controlling them, and to better predict how they may change in the future. PMID:27547344

  11. Planktonic and whole system metabolism in a nutrient rich estuary (the Scheldt estuary)

    Gazeau, Frédéric; Gattuso, Jean-Pierre; Middelburg, Jack J; Brion, Natacha; Schiettecatte, Laure-Sophie; Frankignoulle, Michel; Borges, Alberto

    2005-01-01

    Planktonic gross primary production (GPP), community respiration (CR), and nitrification (NIT) were measured monthly in the Scheldt estuary by the oxygen incubation method in 2003. No significant evolution of planktonic GPP was observed since the 1990s with high rates in the freshwater area (salinity 0; 97 6 65 mmol C m-2 d-1) decreasing seaward (22-37 mmol C m-2 d-1). A significant decrease of NIT was observed with regard to previous investigations although this process still represents up t...

  12. Seasonal patterns in the fish and crustacean community of a turbid temperate estuary (Zeeschelde Estuary, Belgium)

    J. Maes; Taillieu, A.; Damme, P.A. van; Cottenie, K.; Ollevier, F.P.

    1998-01-01

    Fish and crustaceans were sampled for 1 year in the upper reaches of a temperate estuary characterized by high turbidity and a tidal range of up to 5 m. Samples were taken in the cooling-water circuit of the Doel Nuclear Power station (Zeeschelde, Belgium). Between July 1994 and June 1995, 55 fish species, two shrimp species and four crab species were recorded. The fish community was composed of 36 marine species, 16 freshwater species and three diadromous species. Shrimps, Gobiidae and Clupe...

  13. Maturation of the penaeid prawn Metapenaeus moyebi in Mandovi Estuary, Goa

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

    Metapenaeus moyebi contributed a good share of penaeid prawn population in the Mandovi Estuary of Goa, India throughout the year. Both males and females of this species with fully mature gonads were observed in the estuary, suggesting further...

  14. Suspended sediment fluxes in a tropical estuary, west coast of India

    AnilKumar, N.; DineshKumar, P.K.; Srinivas, K.

    Annual transport processes of suspended sediments in Beypore estuary - a tropical estuary along the south west coast of India - were investigated based on time series measurements within the system. It's observed that the sediment transport...

  15. Picophytoplankton community in a tropical estuary: Detection of Prochlorococcus-like populations

    Mitbavkar, S.; Rajaneesh, K.M.; Anil, A.C.; Sundar, D.

    The influence of hydrography on the picophytoplankton (PP) abundance in estuaries was studied by sampling along a salinity gradient in an Indian estuary. Prochlorococcus-like cells were detected at salinities ranging from 0.06 to 35, which otherwise...

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

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

    Circulation and Mixing Process in Vasishta-Godavari Estuary, have been studied by using estuarine classification model. Analysis of salinity, salt budget, diffusion coefficients and flushing times based on salinity data of Vasishta-Godavari estuary...

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

    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.

    Estuaries have been under sampled to establish them as sources or sinks of the atmospheric carbon dioxide. Such poor coverage is well known for tropical, particularly monsoon driven, estuaries. In an attempt to study the variability in CO sub(2...

  18. Impressions from South-West Uganda

    Hardouin, J.

    1987-01-01

    Full Text Available Certain features of the prevailing agricultural and livestock management practices in four districts of the South-West Uganda are briefly described. This area is characterized by rather high elevation, good rainfall, fertile soil and hills with steep slopes and mountains in some parts. In three ofthe four districts land is becoming scarce though agricultural production is high but traditional. Cash and food crop production are prevalent ; the staple food being plantain banana and milk production is noticeable. The economy shows evident difficulties mainly due to the so called mismanaged Amin's regime and the ensuing Liberation War. Comments are made on the Queen Elisabeth National Park and some prices are given.

  19. Contrasting behaviour of trace metals in the Scheldt estuary in 1978 compared to recent years

    Nolting, R.F.; Helder, W.; De Baar, H. J. W.; Gerringa, L.J.A.

    1999-01-01

    Dissolved and particulate trace metals (Cu, Cd, Pb, Zn, Ni, Fe and Mn) measured at six stations along the Scheldt estuary in October/November 1978 are compared with more recent data. Based on Ca content in the suspended matter, three distinct geochemical regions could be distinguished: the upper estuary (salinity 1–7) dominated by fluvial mud, mid-estuary (salinity 7–17) where the composition of the suspended matter remained relatively constant, and the lower estuary where marine mud prevaile...

  20. Effect of Freshwater Influx on Phytoplankton in the Mandovi Estuary (Goa, India) during Monsoon Season: Chemotaxonomy

    Goes, Joaquim I.; Prabhu Matondkar, S. G.; Sushma G. Parab; Helga do R. Gomes

    2013-01-01

    The Mandovi estuary is a prominent water body that runs along the west coast ofIndia. It forms an estuarine network with the adjacent Zuari estuary, connected via the Cumbharjua canal. The physico-chemical conditions seen in the Mandovi estuary are influenced by two factors: the presence of several other groups of phytoplankton, the presence of which is yet to be reported in many other tropical estuaries. It includes chrysophytes, cyanobacteria, prasinophytes, prymnesiophytes and chlorophyte...

  1. Southwest Regional Partnership on Carbon Sequestration

    Brian McPherson

    2006-04-01

    The Southwest Partnership on Carbon Sequestration completed several more tasks during the period of April 1, 2005-September 30, 2005. The main objective of the Southwest Partnership project is to evaluate and demonstrate the means for achieving an 18% reduction in carbon intensity by 2012. While Phase 2 planning is well under way, the content of this report focuses exclusively on Phase 1 objectives completed during this reporting period. Progress during this period was focused in the three areas: geological carbon storage capacity in New Mexico, terrestrial sequestration capacity for the project area, and the Integrated Assessment Model efforts. The geologic storage capacity of New Mexico was analyzed and Blanco Mesaverde (which extends into Colorado) and Basin Dakota Pools were chosen as top two choices for the further analysis for CO{sub 2} sequestration in the system dynamics model preliminary analysis. Terrestrial sequestration capacity analysis showed that the four states analyzed thus far (Arizona, Colorado, New Mexico and Utah) have relatively limited potential to sequester carbon in terrestrial systems, mainly due to the aridity of these areas, but the large land area offered could make up for the limited capacity per hectare. Best opportunities were thought to be in eastern Colorado/New Mexico. The Integrated Assessment team expanded the initial test case model to include all New Mexico sinks and sources in a new, revised prototype model in 2005. The allocation mechanism, or ''String of Pearls'' concept, utilizes potential pipeline routes as the links between all combinations of the source to various sinks. This technique lays the groundwork for future, additional ''String of Pearls'' analyses throughout the SW Partnership and other regions as well.

  2. Riverbed Micromorphology of the Yangtze River Estuary, China

    Shuaihu Wu

    2016-05-01

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

  3. The chemistry of trace elements in estuaries

    Estuarine mixing processes can be generally divided into two stages. In the low-salinity region (226Ra is removed through adsorption by resuspended particles, and added through desorption from riverine suspended particles and input from the pore water. This is shown by the data collected from the Mullica River estuary. Equilibrium-speciation calculation for estuarine water predict that Al and Cu are complexed largely with organic ligands. The extent of Ni complexes with organic ligands in estuarine water depends largely on the concentration of organic ligands. Dissolved Mn and Zn do not form significant fraction of metal-organic complexes. Complexing of Fe with organics can delay precipitation of Fe-hydroxides in the course of estuarine mixing. Metal concentrations in estuarine sediments of the Mullica River are primarily controlled by physical processes. The dominant processes are resuspension and sedimentation for suspended sediments, and longitudinal mixing for bottom sediments. In suspended particles, Fe, Mn, and Zn are largely associated with amorphous material, which is clearly in contrast to those for bottom sediments in which most metals are associated with clay minerals. The coastal waters of New Jersey receive considerable Cu, Ni Mn and Zn from anthropogenic sources, and these metals are largely added in the high salinity region

  4. Attenuation of rare earth elements in a boreal estuary

    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 extract metals from the settling material. Aluminium, Fe and REE transported by the acidic creek were extensively removed in the inner/central estuary where the acidic water was neutralised, whereas Mn was relatively persistent in solution and thus redistributed to particles and deposited further down the estuary. The REE removal was caused by several contemporary mechanisms: co-precipitation with oxyhydroxides (mainly Al but also Fe), complexation with flocculating humic substances and sorption to suspended particles. Down estuary the dissolved REE pool, remaining after removal, was fractionated: the Humic Model after revision and updating, predicted that the dissolved (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.

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

    2007-01-01

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

  6. Nutrient loading tot he St. Lucie Estuary, Florida

    The St. Lucie Estuary receives freshwater input from two free-flowing creeks (the Old South Fork and Ten Mile Creek) and three major drainage canals (C23, C24 and C44). The South Florida Water Management District has monitored nutrient concentrations upstream of discharge structures on the canals since the late 1970s and nutrient levels in the Estuary since 1990. Analysis of nutrient concentrations at the canal discharge structures indicates that the total nitrogen concentrations in all three canals decreased during the period from 1979 to 2000. The phosphorus concentrations in discharges from C24 and C44 were relatively steady during the same time period, while the phosphorus concentration of canal C23 increased. Variation in nutrient loading was dominated by fluctuations in the volume of canal discharges. Analysis of water quality in the estuary showed that total nitrogen and phosphorus concentrations decreased from the upper estuary to the lower estuary. Years with high maximum chlorophyll a concentrations tended to occur in the years in which nutrient loading from the three canals was high. (author)

  7. Metals in sediments and benthic organisms in the Mersey estuary

    Langston, W. J.

    1986-08-01

    Concentrations of twelve metals were determined in sediments, seaweed ( Fucus vesiculosus), winkles ( Littorina littorea), polychaetes ( Nereis diversicolor), suspension feeding bivalves ( Mytilus edulis, Cerastoderma edule) and deposit feeding bivalves ( Macoma balthica, Scrobicularia plana) collected from the Mersey estuary between April 1980 and June 1984. Sediments and organisms in the Mersey are moderately contaminated with most of the metals measured, but mercury concentrations are consistently higher than in other United Kingdom estuaries. Comparisons with other sites in the North West of England indicate that mercury residues in organisms, though primarily dependent on sediment concentrations, are also influenced by complexation with particulate organic matter which reduces the availability of mercury. The biological availability of arsenic in Mersey sediments is similarly influenced by complexation with iron oxyhydroxides. Nereis diversicolor and Macoma balthica are the most suitable indicator species in terms of abundance and widespread distribution along the estuary, and, for the majority of metals, tissue concentrations increase upstream, reflecting corresponding gradients in sediment contamination. However mid-estuarine peaks for tin, chromium copper and nickel in Nereis indicate more localised inputs to the estuary. Correlations between lead in sediments and organisms are poor; it is suggested that hydrophilic alkyl lead compounds may be the predominant biologically available forms. Progressive reductions in mercury contamination in sediments and mercury and lead in organisms have occurred in recent years, which coincide with efforts to reduce inputs of these metals to teh Mersey estuary.

  8. Dissolved organic carbon in the freshwater tidal reaches of the Schelde estuary

    Muylaert, K.; Dasseville, R.; De Brabandere, Loreto;

    2005-01-01

    To unravel the factors that regulate DOC dynamics in the freshwater tidal reaches of the Schelde estuary, DOC concentration and biodegradability were monitored in the upper Schelde estuary and its major tributaries. Although the Schelde estuary possesses a densely populated and industrialized cat...

  9. Eco-Morphological Problems in the Yangtze Estuary and the Western Scheldt

    Vriend, de H.J.; Wang, Z.B.; Ysebaert, T.; Herman, P.M.J.; Ding, P.X.

    2011-01-01

    This paper compares the Yangtze Estuary in China and the Western Scheldt Estuary in The Netherlands by their morphodynamic and ecological systems, their engineering works and estuarine management issues, and the major challenges in studying them. Physically speaking, the two estuaries are very diffe

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

    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.

    in estuaries with deeper photic zone than other estuaries receiving higher suspended matter. The delta13CPOC and delta15CPN data suggest that relatively higher delta13CPOC (-27.9 to -22.6‰) and lower delta15CPN (0.7 to 5.8‰) were noticed in the estuaries...

  11. Effects of heavy metal contamination on the macrobenthic fauna in estuaries: The case of the Seine estuary

    Dauvin, Jean-Claude [Station Marine de Wimereux, Universite des Sciences et Technologies de Lille, CNRS FRE 2816 ELICO - Ecosystemes Littoraux et Cotiers, 28, Avenue Foch, BP 80, F-62930 Wimereux (France)], E-mail: jean-claude.dauvin@univ-lille1.fr

    2008-07-01

    Heavy metal contamination levels are generally higher in estuaries than in the open sea. Some estuaries, the Seine estuary for example, have particularly high pollution levels of metals, yet continue to support a very high benthic biomass and remain quite productive. Measurements of sediment contamination are highly variable due to diverse chemical analysis methods, sediments origin and sources of contaminants found in the estuaries. Salinity appears to be the principal factor controlling contaminant distribution in the sediment and the overlying and/or interstitial waters; it also affects the bioavailability of contaminants in estuarine sediments. Of course, the response to contaminants varies greatly among species and assemblages. Trace metals explain only a small part of the variation in benthic community structure. Some species, such as the shrimp Crangon crangon, appears vulnerable to metal pollution, while other species, such as Scrobicularia plana, are able to tolerate quite high levels of cadmium in their tissue. This paper demonstrates the wide variability of benthic responses to contamination, which is probably due to the high spatio-temporal heterogeneity of the estuary. To reduce the problems due the heterogeneity and variability observed to date in the available results, it will be necessary to encourage integrated estuarine studies, in which sedimentologists, chemists, and biologists work together on the same campaigns at the same sites.

  12. Effects of heavy metal contamination on the macrobenthic fauna in estuaries: the case of the Seine estuary.

    Dauvin, Jean-Claude

    2008-01-01

    Heavy metal contamination levels are generally higher in estuaries than in the open sea. Some estuaries, the Seine estuary for example, have particularly high pollution levels of metals, yet continue to support a very high benthic biomass and remain quite productive. Measurements of sediment contamination are highly variable due to diverse chemical analysis methods, sediments origin and sources of contaminants found in the estuaries. Salinity appears to be the principal factor controlling contaminant distribution in the sediment and the overlying and/or interstitial waters; it also affects the bioavailability of contaminants in estuarine sediments. Of course, the response to contaminants varies greatly among species and assemblages. Trace metals explain only a small part of the variation in benthic community structure. Some species, such as the shrimp Crangon crangon, appears vulnerable to metal pollution, while other species, such as Scrobicularia plana, are able to tolerate quite high levels of cadmium in their tissue. This paper demonstrates the wide variability of benthic responses to contamination, which is probably due to the high spatio-temporal heterogeneity of the estuary. To reduce the problems due the heterogeneity and variability observed to date in the available results, it will be necessary to encourage integrated estuarine studies, in which sedimentologists, chemists, and biologists work together on the same campaigns at the same sites. PMID:18045624

  13. Effects of heavy metal contamination on the macrobenthic fauna in estuaries: The case of the Seine estuary

    Heavy metal contamination levels are generally higher in estuaries than in the open sea. Some estuaries, the Seine estuary for example, have particularly high pollution levels of metals, yet continue to support a very high benthic biomass and remain quite productive. Measurements of sediment contamination are highly variable due to diverse chemical analysis methods, sediments origin and sources of contaminants found in the estuaries. Salinity appears to be the principal factor controlling contaminant distribution in the sediment and the overlying and/or interstitial waters; it also affects the bioavailability of contaminants in estuarine sediments. Of course, the response to contaminants varies greatly among species and assemblages. Trace metals explain only a small part of the variation in benthic community structure. Some species, such as the shrimp Crangon crangon, appears vulnerable to metal pollution, while other species, such as Scrobicularia plana, are able to tolerate quite high levels of cadmium in their tissue. This paper demonstrates the wide variability of benthic responses to contamination, which is probably due to the high spatio-temporal heterogeneity of the estuary. To reduce the problems due the heterogeneity and variability observed to date in the available results, it will be necessary to encourage integrated estuarine studies, in which sedimentologists, chemists, and biologists work together on the same campaigns at the same sites

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

    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)

  15. Cadmium in the Amazonian Guajara Estuary: Distribution and remobilization

    Nascimento, S.F. [Instituto de Quimica, Departamento de Geoquimica, Universidade Federal Fluminense (Brazil)]. E-mail: nascimento@lisa.univ-paris12.fr; Kurzweil, H. [Institut fuer Petrologie, Universitaet Wien (Austria); Wruss, W. [Institut fuer Chemische Technologie anorganischer Stoffe, Technische Univesitaet Wien (Austria); Fenzl, N. [Nucleo de Altos Estudos Amazonicos, Universidade Federal do Para (Brazil)

    2006-03-15

    Extremely high total cadmium concentrations (average about 500 mg/kg) together with very small (average of 1.1 {mu}g/l) dissolved available cadmium have been found in the more acidic deeper layers of the bottom sediments of the Brazilian Amazonian Guajara Estuary. The paper shows that climatic changes and the periodic input of the Atlantic waters into the Estuary appear to have no direct influence on annual average total cadmium concentration, but they affect accumulation, distribution and remobilization of cadmium in different ways during the rainy season (February/March) and the dry season (November/December). Even if only a very small part of the total Cd is available, the concentrations of dissolved Cd in the Estuary are still high enough to cause environmental concern, if compared with concentrations in natural freshwater ecosystems. - Distribution and remobilization of cadmium is affected differently by season.

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

    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 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

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

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

    2012-09-01

    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 methodology 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. PMID:22801380

  18. The distribution of U, Th and 226Ra derived from the phosphate fertilizer industries on an estuarine system in southwest Spain

    This paper reports an extensive study of the presence of natural radioactivity around a phosphate fertilizer factory complex situated in an estuarine area of southwest Spain. The study has concluded that the wastes from such industries are the cause of the enhancement of natural radioactivity in the immediate environment. Thus, significantly high levels of U- and Th-isotopes and 226Ra are detected in water and sediment samples collected in this area. These conclusions based on the enhanced isotopic concentrations are further supported by the measured U, Th and Ra isotopic activity ratios being quite different from any observed elsewhere in undisturbed estuaries. These isotope activity ratios appear to be very sensitive indicators of waste disposal practices in such environments. (Author)

  19. Southwest Region Experiment Station - Final Technical Report

    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

  20. 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...

  1. Hydrogeologic Areas of the Southwest Principal Aquifer (SWPA) study

    U.S. Geological Survey, Department of the Interior — This raster dataset represents the boundaries of the hydrogeologic areas of the Southwest Principal Aquifer (SWPA) study of the National Water Quality Assessment...

  2. 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,...

  3. Benthic fauna of southwest and southeast coasts of India

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

    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...

  4. Shallow-Water Benthic Habitats of Southwest Puerto Rico

    National Oceanic and Atmospheric Administration, Department of Commerce — Shallow-water (<30m) benthic habitat maps of the nearshore marine environment of two areas in Southwest Puerto Rico (PR), including the Guanica Bay/La Parguera...

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

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

    2008-02-05

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

  6. Predicting fish community properties within estuaries: Influence of habitat type and other environmental features

    França, Susana; Vasconcelos, Rita P.; Fonseca, Vanessa F.; Tanner, Susanne E.; Reis-Santos, Patrick; Costa, Maria José; Cabral, Henrique N.

    2012-07-01

    Statistical models predicting species distributions are essential not only to increase knowledge on species but for their application in conservation and ecologically-based management. The variation of fish species richness and abundance in the most representative habitats (saltmarsh, mudflat and subtidal) in five estuaries along the Portuguese coast was analysed through seasonal sampling surveys in 2009. Generalized additive models (GAM) were developed to describe the variation of species richness and abundances with a set of geomorphologic, hydrologic and environmental characteristics from the sampled estuaries and habitats. GAM were chosen as the complex interactions dominating these ecosystems and species distribution are non-linear. Final models built for each estuary and for all estuaries together performed well during the calibration phase and also during the validation phase, where an unused data sub-set from each estuary was used. There was not a similar combination of variables retained by the models for the studied estuaries but factors such as the area of the habitat, the distance to estuary mouth, percentage of mud in the sediment and depth were commonly retained. The partial effect of these predictor variables on the variation of species richness and abundance in the estuaries varied markedly and the importance of preserving the heterogeneity of habitats within estuaries was highlighted. Models for each individual estuary performed better than models for estuaries combined. Predictive models could be useful as a preliminary tool to prepare long-term conservation plans at different scales.

  7. A monsoon-like Southwest Australian circulation and its relation with rainfall in Southwest Western Australia

    Feng, Juan; Li, Jianping; Li, Yun

    2010-05-01

    Using the NCEP/NCAR, ERA-40 reanalysis, and precipitation data from CMAP and Australian Bureau of Meteorology, the variability and circulation features influencing the southwest Western Australia (SWWA) winter rainfall are investigated. It is found that the climate of southwest Australia bears a strong seasonality in the annual cycle and exhibits a monsoon-like atmospheric circulation, which is termed as the southwest Australian circulation (SWAC) for its several distinct features characterizing a monsoonal circulation: the seasonal reversal of winds, alternate wet and dry seasons, and an evident land-sea thermal contrast. The seasonal march of the SWAC in extended winter (May to October) is demonstrated by pentad data. An index based on the dynamics normalized seasonality was introduced to describe the behavior and variation of the winter SWAC. It is found that the winter rainfall over SWWA has a significant positive correlation with the SWAC index in both early (May to July) and late (August to October) winter. In weaker winter SWAC years there is an anti-cyclonic anomaly over southern Indian Ocean resulting in weaker westerlies and northerlies which are not favorable for more rainfall over SWWA, and the opposite combination is true in the stronger winter SWAC years. The SWAC explains not only a large portion of the interannual variability of SWWA rainfall in both early and late winter, but also the long term drying trend over SWWA in early winter. The well-coupled SWAC-SWWA rainfall relationship seems to be largely independent of the well-known effects of large-scale atmospheric circulations such as the Southern Hemisphere Annular Mode (SAM), El Niño/Southern Oscillation (ENSO), Indian Ocean Dipole (IOD) and ENSO Modoki (EM). The result offers qualified support for the argument that the monsoon-like circulation may contribute to the rainfall decline in early winter over SWWA.

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

    Ganachaud, Alexandre; Cravatte, Sophie; A. Melet; Schiller, A.; Holbrook, N J; Sloyan, B.M.; Widlansky, M.J.; Bowen, M; Verron, J.; Wiles, P; K. Ridgway; Sutton, P.; Sprintall, J.; Steinberg, C.; Brassington, G.

    2014-01-01

    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...

  9. Jurassic zircons from the Southwest Indian Ridge.

    Cheng, Hao; Zhou, Huaiyang; Yang, Qunhui; Zhang, Lingmin; Ji, Fuwu; Dick, Henry

    2016-01-01

    The existence of ancient rocks in present mid-ocean ridges have long been observed but received less attention. Here we report the discovery of zircons with both reasonably young ages of about 5 Ma and abnormally old ages of approximate 180 Ma from two evolved gabbroic rocks that were dredged from the Southwest Indian Ridge (SWIR) in the Gallieni fracture zone. U-Pb and Lu-Hf isotope analyses of zircons were made using ion probe and conventional laser abrasion directly in petrographic thin sections. Young zircons and their host oxide gabbro have positive Hf isotope compositions (εHf = +15.7-+12.4), suggesting a highly depleted mantle beneath the SWIR. The spread εHf values (from-2.3 to-4.5) of abnormally old zircons, together with the unradiogenic Nd-Hf isotope of the host quartz diorite, appears to suggest an ancient juvenile magmatism along the rifting margin of the southern Gondwana prior to the opening of the Indian Ocean. A convincing explanation for the origin of the unusually old zircons is yet to surface, however, an update of the theory of plate tectonics would be expected with continuing discovery of ancient rocks in the mid-oceanic ridges and abyssal ocean basins. PMID:27185575

  10. Jurassic zircons from the Southwest Indian Ridge

    Cheng, Hao; Zhou, Huaiyang; Yang, Qunhui; Zhang, Lingmin; Ji, Fuwu; Dick, Henry

    2016-05-01

    The existence of ancient rocks in present mid-ocean ridges have long been observed but received less attention. Here we report the discovery of zircons with both reasonably young ages of about 5 Ma and abnormally old ages of approximate 180 Ma from two evolved gabbroic rocks that were dredged from the Southwest Indian Ridge (SWIR) in the Gallieni fracture zone. U–Pb and Lu–Hf isotope analyses of zircons were made using ion probe and conventional laser abrasion directly in petrographic thin sections. Young zircons and their host oxide gabbro have positive Hf isotope compositions (εHf = +15.7–+12.4), suggesting a highly depleted mantle beneath the SWIR. The spread εHf values (from‑2.3 to‑4.5) of abnormally old zircons, together with the unradiogenic Nd-Hf isotope of the host quartz diorite, appears to suggest an ancient juvenile magmatism along the rifting margin of the southern Gondwana prior to the opening of the Indian Ocean. A convincing explanation for the origin of the unusually old zircons is yet to surface, however, an update of the theory of plate tectonics would be expected with continuing discovery of ancient rocks in the mid-oceanic ridges and abyssal ocean basins.

  11. TAP Report - Southwest Idaho Juniper Working Group

    Gresham, Garold Linn [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-09-01

    There is explicit need for characterization of the materials for possible commercialization as little characterization data exists. Pinyon-juniper woodlands are a major ecosystem type found in the Southwest and the Intermountain West regions of the United States including Nevada, Idaho and Oregon. These widespread ecosystems are characterized by the presence of several different species of pinyon and juniper as the dominant plant cover. Since the 1800s, pinyon-juniper woodlands have rapidly expanded their range at the expense of existing ecosystems. Additionally, existing woodlands have become denser, progressively creating potential fire hazards as seen in the Soda Fire, which burned more than 400 sq. miles. Land managers responsible for these areas often desire to reduce pinyon-juniper coverage on their lands for a variety of reasons, as stated in the Working Group objectives. However, the cost of clearing thinning pinyon-juniper stands can be prohibitive. One reason for this is the lack of utilization options for the resulting biomass that could help recover some of the cost of pinyon-juniper stand management. The goal of this TAP effort was to assess the feedstock characteristics of biomass from a juniper harvested from Owyhee County to evaluate possible fuel and conversion utilization options.

  12. Variability of the southwest Indian Ocean.

    de Ruijter, Wilhelmus P M; Ridderinkhof, Herman; Schouten, Mathijs W

    2005-01-15

    The variability in the southwest Indian Ocean is connected to the basin-scale and global-scale ocean circulation. Two bands of enhanced variability stretch across the Southern Indian Ocean east of Madagascar around 12 degrees S and 25 degrees S, respectively. They mark the preferred routes along which anomalies, generated by varying forcing over the central basin, near the eastern boundary or in the equatorial region, propagate westward as baroclinic Rossby waves. Sea-surface height anomalies pass along the northern tip of Madagascar and are observed by satellite altimetry to propagate into the central Mozambique Channel. There, eddies are subsequently formed that propagate southward into the Agulhas retroflection region. The anomalies along the southern band trigger the formation of large dipolar vortex pairs in the separation region of the East Madagascar Current at the southern tip of the island. South of Africa these eddies and dipoles trigger the shedding of Agulhas Rings that feed the Atlantic meridional overturning circulation with warm, salty, Indian Ocean water. Interannual variability of the forcing over the Indian Ocean, such as that associated with the Indian Ocean Dipole/El Nino climate modes, propagates along these pathways and leads to associated modulations of the eddy transports into the South Atlantic. PMID:15598623

  13. Distribution of tributyltin (TBT) in the Mandovi estuary

    Bhosle, N.B.

    is known about the levels of onrganotins in Indian waters, sediments, and animals. Mandovi estuary, Goa, India is one of the few marine areas of the country where some information on TBT levels is available. An attempt to summarise what is known about TBT...

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

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

    An assessment of the stake net fishery in the Mandovi and Zuari estuaries of Goa revealed that Metapenaeus moyebi, a penaeid prawn hitherto rarely recorded in Indian waters, formed a good percentage of the estuarine prawn fishery of Goa. At one...

  15. Estuaries May Face Increased Parasitism as Sea Levels Rise

    Wendel, JoAnna

    2014-12-01

    Invertebrates in estuaries could be at a greater risk of parasitism as climate change causes sea levels to rise. A new paper published 8 December in Proceedings of the National Academy of Sciences of the United States of America (doi:10.1073/pnas.1416747111) describes how rapid sea level rise in the Holocene affected the population of parasitic flatworms called trematodes.

  16. A new analytical framework for tidal propagation in estuaries

    Cai, H.

    2014-01-01

    The ultimate aim of this thesis is to enhance our understanding of tidal wave propagation in convergent alluvial estuaries (of infinite length). In the process, a new analytical model has been developed as a function of externally defined dimensionless parameters describing friction, channel converg

  17. Environmental flow assessments in estuaries related to preference of phytoplankton

    Z. F. Yang; Sun, T; Zhao, R.

    2014-01-01

    We developed an approach to assess environmental flows in estuaries related to preference of phytoplankton considering the complex relationship between hydrological modification and biomass in ecosystems. As a first step, a relationship was established between biomass requirements for organisms of primary and higher nutritional levels based on the principle of nutritional energy flow of ecosystem. Then, diagnostic pigments were employed to represent phytopl...

  18. Time scales in Galveston Bay: An unsteady estuary

    Rayson, Matthew D.; Gross, Edward S.; Hetland, Robert D.; Fringer, Oliver B.

    2016-04-01

    Estuarine time scales including the turnover, particle e-folding time, the age (calculated with a passive tracer), and residence time (calculated with Lagrangian particles) were computed using a three-dimensional hydrodynamic model of Galveston Bay, a low-flow, partially stratified estuary. Time scales were computed during a time period when river flow varied by several orders of magnitude and all time scales therefore exhibited significant temporal variability because of the unsteadiness of the system. The spatial distributions of age and residence time were qualitatively similar and increased from 15 days in a shipping channel to >45 days in the upper estuary. Volume-averaged age and residence time decreased during high-flow conditions. Bulk time scales, including the freshwater and salinity turnover times, were far more variable due to the changing river discharge and salt flux through the estuary mouth. A criterion for calculating a suitable averaging time is discussed to satisfy a steady state assumption and to estimate a more representative bulk time scale. When scaled with a freshwater advective time, all time scales were approximately equal to the advective time scale during high-flow conditions and many times higher during low-flow conditions. The mean age, Lagrangian residence, and flushing times exhibited a relationship that was weakly dependent on the freshwater advective time scale demonstrating predictability even in an unsteady, realistic estuary.

  19. Man's Impact on the Environment: The Estuary as an Ecosystem.

    Brevard County School Board, Cocoa, FL.

    This environmental education guide focuses on man's impact on the estuary. The program contained in the guide is developed around the following nine questions: (1) What is a definition of the ecosystem being investigated?; (2) What are some of the biotic and abiotic features of the ecosystem and how do these features interrelate?; (3) Where are…

  20. Contaminants of emerging concern in a large temperate estuary.

    Meador, James P; Yeh, Andrew; Young, Graham; Gallagher, Evan P

    2016-06-01

    This study was designed to assess the occurrence and concentrations of a broad range of contaminants of emerging concern (CECs) from three local estuaries within a large estuarine ecosystem. In addition to effluent from two wastewater treatment plants (WWTP), we sampled water and whole-body juvenile Chinook salmon (Oncorhynchus tshawytscha) and Pacific staghorn sculpin (Leptocottus armatus) in estuaries receiving effluent. We analyzed these matrices for 150 compounds, which included pharmaceuticals, personal care products (PPCPs), and several industrial compounds. Collectively, we detected 81 analytes in effluent, 25 analytes in estuary water, and 42 analytes in fish tissue. A number of compounds, including sertraline, triclosan, estrone, fluoxetine, metformin, and nonylphenol were detected in water and tissue at concentrations that may cause adverse effects in fish. Interestingly, 29 CEC analytes were detected in effluent and fish tissue, but not in estuarine waters, indicating a high potential for bioaccumulation for these compounds. Although concentrations of most detected analytes were present at relatively low concentrations, our analysis revealed that overall CEC inputs to each estuary amount to several kilograms of these compounds per day. This study is unique because we report on CEC concentrations in estuarine waters and whole-body fish, which are both uncommon in the literature. A noteworthy finding was the preferential bioaccumulation of CECs in free-ranging juvenile Chinook salmon relative to staghorn sculpin, a benthic species with relatively high site fidelity. PMID:26907702

  1. A model of nematode dynamics in the Westerschelde estuary

    Li, J.; Vincx, M.; Herman, P.M.J.

    1996-01-01

    We developed a time dynamic model to investigate the temporal dynamics of nematode community in the brackish zone of the Westerschelde Estuary. The biomass of four nematode feeding groups observed from March 1991 to February 1992 is used to calibrate the model. Using environmental data as the input,

  2. Sediment transport investigations in Hugli estuary using radiotracer technique

    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

  3. Production and consumption of biological particles in temperate tidal estuaries

    Heip, C.H.R.; Goosen, N.K.; Herman, P.M.J.; Kromkamp, J.C.; Middelburg, J.J.; Soetaert, K.E.R.

    1995-01-01

    The question is reviewed whether a balance exists between production and consumption of biological particles in temperate tidal estuaries and what the relationships are between the magnitude of production and consumption processes and system carbon metabolism. The production terms considered are pri

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

    Sharma, P.; Zingde, M.D.

    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....

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

    Alagarsamy, R.

    Total organic carbon (TOC) in surficial sediments in Mandovi Estuary, Goa, India varies widely from 0.1 to 3% (av. 1.05%). Highest values of TOC (2.4-3%) lie close to the mouth region and indicate no definite trend in its variation in the estuarine...

  6. Revised predictive equations for salt intrusion modelling in estuaries

    J. I. A. Gisen

    2015-01-01

    Full Text Available For one-dimensional salt intrusion models to be predictive, we need predictive equations to link model parameters to observable hydraulic and geometric variables. The one-dimensional model of Savenije (1993b made use of predictive equation for the Van der Burgh coefficient K and the dispersion at the seaward boundary D0. Here we have improved these equations by using an expanded database, including new previously un-surveyed estuaries. Furthermore, we derived a revised predictive equation for the dispersion at tidal average (TA condition and with the boundary situated at the well identifiable inflection point where the estuary changes from wave-dominated to tide-dominated geometry. We used 89 salinity profiles in 30 estuaries (including 7 recently studied estuaries in Malaysia, and empirically derived a range of equations using various combinations of dimensionless parameters. We split our data in two separated datasets: (1 with more reliable data for calibration, and (2 with less reliable data for validation. The dimensionless parameters that gave the best performance depended on the geometry, tidal strength, friction and the Richardson Number. The limitation of the equations is that the friction is generally unknown. In order to overcome this problem, a coupling has been made with the analytical hydraulic model of Cai et al. (2012, which makes use of observed tidal damping and by which the friction can be determined.

  7. Revised predictive equations for salt intrusion modelling in estuaries

    J. I. A. Gisen

    2015-06-01

    Full Text Available For one-dimensional salt intrusion models to be predictive, we need predictive equations to link model parameters to observable hydraulic and geometric variables. The one-dimensional model of Savenije (1993b made use of predictive equations for the Van der Burgh coefficient $K$ and the dispersion at the seaward boundary D0. Here we have improved these equations by using an expanded database, including new previously un-surveyed estuaries. Furthermore, we derived a revised predictive equation for the dispersion at tidal average condition and with the boundary situated at the well identifiable inflection point where the estuary changes from wave-dominated to tide-dominated geometry. We used 89 salinity profiles in 30 estuaries (including seven recently studied estuaries in Malaysia, and empirically derived a range of equations using various combinations of dimensionless parameters. We split our data in two separated data sets: (1 with more reliable data for calibration, and (2 with less reliable data for validation. The dimensionless parameters that gave the best performance depended on the geometry, tidal strength, friction and the Richardson number. The limitation of the equations is that the friction is generally unknown. In order to overcome this problem, a coupling has been made with the analytical hydraulic model of Cai et al. (2012, which makes use of observed tidal damping and by which the friction can be determined.

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

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

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

  9. Water and suspended sediment dynamics in the Sungai Selangor estuary

    Observations of salinity, temperature, suspended sediment concentration (SSC) and tidal current velocity were made in the lower and along the longitudinal axis sungai Selangor estuary over near-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,'/) 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)

  10. Environmental features and macrofauna of Kahana Estuary, Oahu, Hawaii

    Maciolek, J.A.; Timbol, A.S.

    1981-01-01

    Lack of ecological information on Hawaiian estuaries prompted an intensive 2-year study of a small (5.7 ha) stream-mouth estuary on windward Oahu. Water quality and macrofauna were sampled weekly at seven stations. The water mass was strongly stratified vertically except during freshets. Average values for water column temperature and bottom salinity were 23.2°C and 12‰ at the head to 28.3°C and 28‰ at the mouth. Dissolved oxygen saturation in the water column varied from about 50% at night to 140% in the afternoon. Usually, bottom waters were 3–6°C warmer than surface waters and sometimes showed severe oxygen depletion.Macrofauna, collected primarily by seining, consisted mainly of decapod crustaceans (four species of crabs, seven species of shrimps) and fishes (24 species). Other typical estuarine taxons (mollusks, barnacles, polychaetes) were scarce or absent. Diversity increased seaward from 14 species near the estuary head to 29 species near the mouth. Three species of crustaceans and six of fishes were captured at all stations. Most abundant were the native prawn, Macrobrachium grandimanus, and mullet, Mugil cephalus. Perennially resident adults occurred among crustaceans and gobioid fishes; most other fishes were present as juveniles and sporadic adults. Comparisons with other data suggest that more than 50 species of native fishes may occur in Hawaiian estuaries, and that estuarine macrofaunal diversity on oceanic islands is much lower than on continents at similar latitudes.

  11. Laboratory Investigations on Estuary Salinity Mixing: Preliminary Analysis

    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.

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

    2005-01-01

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

  13. Phytoplankton diversity and primary production in Poonthura estuary, south Kerala

    Ritakumari, S.D.; Shibu, S.

    2007-01-01

    Seasonal variations in the phytoplankton density, diversity, gross production and related physicochemical parameters of Poonthura estuary have been followed for a period of one year. The polluted nature of the water body favored a higher density of phytoplankters, which exhibited a positive correlation with gross production. The influence of various physicochemical parameters, phytoplankton density and species diversity on gross production is discussed.

  14. Biogeochemical value of managed realignment, Humber estuary, UK

    We outline a plausible, albeit extreme, managed realignment scenario ('Extended Deep Green' scenario) for a large UK estuary to demonstrate the maximum possible biogeochemical effects and economic outcomes of estuarine management decisions. Our interdisciplinary approach aims to better inform the policy process, by combining biogeochemical and socioeconomic components of managed realignment schemes. Adding 7494 ha of new intertidal area to the UK Humber estuary through managed realignment leads to the annual accumulation of a 1.2 x 105 t of 'new' sediment and increases the current annual sink of organic C and N, and particle reactive P in the estuary by 150%, 83% and 50%, respectively. The increase in intertidal area should also increase denitrification. However, this positive outcome is offset by the negative effect of enhanced greenhouse gas emissions in new marshes in the low salinity region of the estuary. Short-term microbial reactions decrease the potential benefits of CO2 sequestration through gross organic carbon burial by at least 50%. Net carbon storage is thus most effective where oxidation and denitrification reactions are reduced. In the Humber this translates to wet, saline marshes at the seaward end of estuaries. Cost-benefit analysis (CBA) was used to determine the economic efficiency of the Extended Deep Green managed realignment. When compared to a 'Hold-the-Line' future scenario, i.e. the present state/extent of sea defences in the estuary, the CBA shows that managed realignment is cost effective when viewed on > 25 year timescales. This is because capital costs are incurred in the first years, whereas the benefits from habitat creation, carbon sequestration and reduced maintenance costs build up over time. Over 50- and 100-year timescales, the Extended Deep Green managed realignment scenario is superior in efficiency terms. The increased sediment accumulation is also likely to enhance storage of contaminant metals. In the case of Cu, a metal

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

    V. R. Shevchenko

    2005-01-01

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

  16. Columbia River Estuary Ecosystem Classification — Concept and application

    Simenstad, Charles A.; Burke, Jennifer L.; O'Connor, Jim E.; Cannon, Charles; Heatwole, Danelle W.; Ramirez, Mary F.; Waite, Ian R.; Counihan, Timothy D.; Jones, Krista L.

    2011-01-01

    This document describes the concept, organization, and application of a hierarchical ecosystem classification that integrates saline and tidal freshwater reaches of estuaries in order to characterize the ecosystems of large flood plain rivers that are strongly influenced by riverine and estuarine hydrology. We illustrate the classification by applying it to the Columbia River estuary (Oregon-Washington, USA), a system that extends about 233 river kilometers (rkm) inland from the Pacific Ocean. More than three-quarters of this length is tidal freshwater. The Columbia River Estuary Ecosystem Classification ("Classification") is based on six hierarchical levels, progressing from the coarsest, regional scale to the finest, localized scale: (1) Ecosystem Province; (2) Ecoregion; (3) Hydrogeomorphic Reach; (4) Ecosystem Complex; (5) Geomorphic Catena; and (6) Primary Cover Class. We define and map Levels 1-3 for the entire Columbia River estuary with existing geospatial datasets, and provide examples of Levels 4-6 for one hydrogeomorphic reach. In particular, three levels of the Classification capture the scales and categories of ecosystem structure and processes that are most tractable to estuarine research, monitoring, and management. These three levels are the (1) eight hydrogeomorphic reaches that embody the formative geologic and tectonic processes that created the existing estuarine landscape and encompass the influence of the resulting physiography on interactions between fluvial and tidal hydrology and geomorphology across 230 kilometers (km) of estuary, (2) more than 15 ecosystem complexes composed of broad landforms created predominantly by geologic processes during the Holocene, and (3) more than 25 geomorphic catenae embedded within ecosystem complexes that represent distinct geomorphic landforms, structures, ecosystems, and habitats, and components of the estuarine landscape most likely to change over short time periods.

  17. Flux of 238U and 232Th in Changjiang estuary

    The study of fluxes of the U, Th of Changjiang River into the East China Sea and its adjacent waters is basic work to understanding of U, Th tracer theirselves and their corresponding biogeochemical cycles process in estuaries, coastal. By sampling in the Xuliujing (i.e. the interface between fresh water and sea water) every month, 200 L water was filtered through 0.45μm fabric cartridge to collect particle nuclides. The dissolved nuclides were co-precipitated using Fe(OH)3 and MnO2. The range of 238U activity in water is 2.30-10.32 Bq·m-3, with an average of 5.48±1.19 Bq·m-3; the activity of 232Th is 1.08-2.32 Bq·m-3, with an average of 1.75±0.29 Bq·m-3. Changjiang River conveyed 238U 4.06 x 1012Bq, 232Th 1.54 x 1012 Bq into the estuary every year. Further study of the seasonal variations 238U, 232Th input to the sea, indicating that: the activity of 238U and Changjiang River estuary water flux have a certain degree of negative correlation (R2=0.65, n=12); the main source of 232Th is the weathering of the river. The activity of 232Th is large on the spring and autumn because of strong weathering in Changjiang Basin comparison with other seasons. Compared with the other estuaries in the world, the flux of 238U and 232Th of the Changjiang River estuary is large because of its large fluxes of sediments and runoff in the world. (authors)

  18. Spacecraft computer technology at Southwest Research Institute

    Shirley, D. J.

    1993-01-01

    Southwest Research Institute (SwRI) has developed and delivered spacecraft computers for a number of different near-Earth-orbit spacecraft including shuttle experiments and SDIO free-flyer experiments. We describe the evolution of the basic SwRI spacecraft computer design from those weighing in at 20 to 25 lb and using 20 to 30 W to newer models weighing less than 5 lb and using only about 5 W, yet delivering twice the processing throughput. Because of their reduced size, weight, and power, these newer designs are especially applicable to planetary instrument requirements. The basis of our design evolution has been the availability of more powerful processor chip sets and the development of higher density packaging technology, coupled with more aggressive design strategies in incorporating high-density FPGA technology and use of high-density memory chips. In addition to reductions in size, weight, and power, the newer designs also address the necessity of survival in the harsh radiation environment of space. Spurred by participation in such programs as MSTI, LACE, RME, Delta 181, Delta Star, and RADARSAT, our designs have evolved in response to program demands to be small, low-powered units, radiation tolerant enough to be suitable for both Earth-orbit microsats and for planetary instruments. Present designs already include MIL-STD-1750 and Multi-Chip Module (MCM) technology with near-term plans to include RISC processors and higher-density MCM's. Long term plans include development of whole-core processors on one or two MCM's.

  19. Feeding preferences of estuarine mysids Neomysis integer and Rhopalophthalmus tartessicus in a temperate estuary (Guadalquivir Estuary, SW Spain)

    Vilas, César; Drake, Pilar; Fockedey, Nancy

    2008-04-01

    Mysid shrimps are an important component of estuarine food webs because they play a key role in energy transfer as intermediate prey. We investigated the seasonal, tidal and depth specific variation in the diet of the estuarine mysids Neomysis integer and Rhopalophthalmus tartessicus and explored its implications for the planktonic community structure of a temperate estuary (Guadalquivir Estuary, SW Spain). Neomysis integer is an opportunistic omnivore feeding mainly on mesozooplankton and on members of the detrital-microbial loop, shifting prey seasonally according to availability. In contrast, R. tartessicus showed a more carnivorous diet and shifted its target prey during seasons of low resource availability. Despite statistically significant differences in diet composition, both species shared prey of similar size, particularly juvenile Mesopodopsis slabberi, the most abundant mysid species in this estuary, and copepods. Although these similarities imply inter-specific resource competition, their co-existence is achieved by niche partitioning and spatial segregation: the higher osmoregulatory capacity and foraging plasticity of N. integer confers a broader niche breadth for this species allowing N. integer to inhabit the more stressful oligohaline region of the estuary where R. tartessicus cannot survive. We propose that this mechanism relaxes the potential for competition between N. integer and R. tartessicus.

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

    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

  1. 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

    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...

  2. 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

    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...

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

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

    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...

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

    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

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

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

    2008-02-20

    The purpose of this document is to describe research, monitoring, and evaluation (RME) for the Federal Columbia River Estuary Program, hereafter called 'the Estuary Program'. The intent of this RME effort is to provide data and information to evaluate progress toward meeting program goals and objectives and support decision making in the Estuary Program. The goal of the Estuary Program is to understand, conserve, and restore the estuary ecosystem to improve the performance of listed salmonid populations. The Estuary Program has five general objectives, designed to fulfill the program goal, as follows: (1) Understand the primary stressors affecting ecosystem controlling factors, such as ocean conditions and invasive species. (2) Conserve and restore factors controlling ecosystem structures and processes, such as hydrodynamics and water quality. (3) Increase the quantity and quality of ecosystem structures, i.e., habitats, juvenile salmonids use during migration through the estuary. (4) Maintain the food web to benefit salmonid performance. (5) Improve salmonid performance in terms of life history diversity, foraging success, growth, and survival. The goal of estuary RME is to provide pertinent and timely research and monitoring information to planners, implementers, and managers of the Estuary Program. The goal leads to three primary management questions pertaining to the main focus of the Estuary Program: estuary habitat conservation and restoration. (1) Are the estuary habitat actions achieving the expected biological and environmental performance targets? (2) Are the offsite habitat actions in the estuary improving juvenile salmonid performance and which actions are most effective at addressing the limiting factors preventing achievement of habitat, fish, or wildlife performance objectives? (3) What are the limiting factors or threats in the estuary/ocean preventing the achievement of desired habitat or fish performance objectives? Performance measures

  7. The variations of suspended sediment concentration in Yangtze River Estuary

    杨云平; 张明进; 李义天; 张为

    2015-01-01

    With the Yangtze River Estuary as an example, this paper analyzes the influence of human activity on the sea water content, the sediment content and the regional transport situation. In both flood seasons and dry seasons, as well as in the whole year, the sediment discharge rate and the suspended sediment concentration (SSC) in the estuary area of the Yangtze River show decreasing trends. In the estuary area, the amount of sediment transported into the South and North Branches and the offshore area is also in a decreasing trend over the years. The SSCs at the sections at the entrances of the South Branch, the South Channel, the North Channel and the South Passage in the Yangtze River Estuary show decreasing trends during 1959-2011. The remote-sensing data reveal that for the same runoff and tidal current combination, the SSC in the surface water is decreased, caused by the dramatic decrease in the sediment discharge and the sediment content from the watershed. Although the SSC in the offshore area does not exhibit an apparent decreasing trend, the SSC in the nearshore area drops by 21.42% during the period of 2003-2011 as compared with that during the period of 1985-2002 before the impounding of the Three Gorges Reservoir. The sediment re-suspension in the estuary slows down the reduction of the SSC. The period of 2003-2011 is dry years for the Yangtze River, when the flow is relatively low. The peak value of the SSC in the coast area shifts inwards for about 1/6°degree of longitude. Due to the deepwater channel improvement project in the North Passage at the Yangtze River Estuary in 1998, the SSC in the waterway area is decreased. With the decrease of the divided flow ratio and the sediment splitting ratio in the entrance and the exit of the North Passage, the SSC in the upper and lower reaches of the North Passage during the period of 2008-2011 is decreased by about 14.25% as compared with that during the period of 2000-2007. Primarily due to the jetty at the

  8. Abundance, seasonal patterns and diet of the non-native jellyfish Blackfordia virginica in a Portuguese estuary

    Marques, F.; Chainho, P.; Costa, J. L.; Domingos, I.; Angélico, M. M.

    2015-12-01

    Blackfordia virginica, a non-indigenous hydrozoan introduced in many systems around the world, has been observed in the Mira estuary, southwest of Portugal, since 1984. Monthly sampling (January 2013-January 2014) at a fixed location with high abundance of the medusae confirmed the occurrence of a seasonal cycle associated with temperature and photoperiod. The beginning of the medusa cycle occurred in May immediately after the spring zooplankton bloom during April. Examination of the gut contents of B. virginica medusae revealed that copepods, the most abundant group in the zooplankton community, were highly predated. Barnacle nauplii, decapod crustacean larvae and anchovy eggs were also identified in the guts. The medusae showed positive selection for copepods, and negative selection for barnacle nauplii, decapod crustacean larvae and anchovy eggs. The mortality rate of copepods (used as a model prey group) induced by medusae predation was estimated and showed the potential impact of this species in the ecosystem, ranging between 2.34 d-1 and 0.02 d-1, with a minimum copepod half-life of 0.30 days.

  9. Plastic pollution in five urban estuaries of KwaZulu-Natal, South Africa.

    Naidoo, Trishan; Glassom, David; Smit, Albertus J

    2015-12-15

    Monitoring plastic concentrations in estuaries is vital in assessing the magnitude of terrestrial inputs to oceanic environments. Data on plastics ≤ 5 mm in estuaries are scant. This study determined microplastic levels within five estuaries along the Durban coastline and on intervening beaches. Plastics were isolated from estuarine sediment, beach sediment and the surface water of each estuary and characterised. Sediment at the Bayhead area of Durban harbour had the highest average plastic concentrations (745.4 ± 129.7 particles per 500 ml) and an attenuating concentration trend away from the city centre was found. Prevailing south to north longshore drift was hypothesised to result in plastic accumulation on the northern shores of beaches with estuarine effluents, however, this was not found. Fragments composed the largest percent of plastics (59%) found in Bayhead, whereas fibres dominated other estuaries with proportions ranging from 38% of total plastics in the uMgeni estuary to 66% in the Mdloti. PMID:26476863

  10. Estuary response to an abrupt, large increase in groundwater nitrate input

    Long term measurements of NO3- concentrations in two estuaries on Buzzards Bay, Massachusetts, USA, coupled with a large, step-wise increase in the groundwater NO3- to one of those estuaries, have allowed the effects on the estuary to be isolated and quantified. The results show that prior to the abrupt increase, the estuary responded in a linear manner to NO3- input, as suggested in the literature. After the abrupt increase, the estuary initially absorbed the greatly increased groundwater input, and after a year the response became a fluctuating variable with periods of less than 1 year. It is proposed that this indicates increased recycling from the sediments. This behavior is consistent with models of nutrient-induced regime shift in its early stages, as described in the literature. Future isotopic analysis is suggested as a means to confirm the estuary mechanism.

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

    Yen-Chang Chen; Wu-Seng Lung; Han-Chung Yang; Bo-Jhih Chen; Chien-Hung Chen

    2014-01-01

    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 qua...

  12. ENDIS-RISKS: endocrine disruption in the Scheldt estuary - a field study

    Rappé, K.; Ghekiere, A; Noppe, H; Monteyne, E.; Fockedey, N.; Janssen, C.; De Brabander, H.; Roose, P.; Vincx, M.

    2007-01-01

    ENDIS-RISKS, a multidisciplinary research project with five institutes, evaluates the distribution, exposure and effects of endocrine disruptors in the Scheldt Estuary. This estuary is known to be one of the most polluted estuaries in the world. Untreated domestic wastewater and effluents of the industrial areas of Ghent and Antwerp are to a large extent responsible for this pollution. During an intensive field study of four years, eight sampling campaigns were executed on seven sampling poin...

  13. The meiofauna distribution in correlation with environmental characteristics in 5 Mekong estuaries, Vietnam

    Ngo, X.Q.; Smol, N.; Vanreusel, A.

    2013-01-01

    Meiofauna assemblages in 5 estuaries of the Mekong river system (Cua Tieu, Cua Dai, Ba Lai, Co Chien and Dinh An) were sampled for community analysis in March 2009, the dry season. The objectives of this research were to provide the first base line survey of meiofauna assemblages in the 5 Mekong estuaries, and to understand how environmental characteristics affect the densities, diversity and structure of the meiofauna. In each estuary, three to four sampling stations were chosen along the sa...

  14. Morphodynamics of a gravel-dominated macrotidal estuary: Rio Grande, Tierra del Fuego

    Federico I. Isla; Gustavo G. Bujalesky

    2004-01-01

    Rio Grande city (Tierra del Fuego) is located on two attached beach systems, one of Upper Pleistocene (Sangamonian) and the other of Holocene age. Both gravel spits grew from north to south modifying the inlet of the Rio Grande estuary. The present estuary is constrained by the modern and recurved spit Popper Spit. The main characteristic of this macrotidal estuary is that both margins and the bottom are mainly composed of rounded gravel. Expansion of the city is limited by oceanic and estuar...

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

    Guelinckx, J.; Maes, J.; De Brabandere, Loreto;

    2006-01-01

    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...

  16. Persistence and Non-target Impact of Imazapyr Associated with Smooth Cordgrass Control in an Estuary

    Patten, Kim

    2003-01-01

    The herbicide (±-2-[4,5-dihydro-4-methyl-4-(1-methylethyl)- 5-oxo-1 H -imidazol-2-yl]-3-pyridinecarboxylic acid (imazapyr) has shown potential to control smooth cordgrass (Spartina alterniflora Loisel), a noxious weed in many estuaries throughout the world. Research was conducted under tidal estuary conditions in Willapa Bay, Washington, to determine imazapyr’s persistence and aquatic risk and impact to non-target estuary species. Persistence of imazapyr in water...

  17. The contribution of scientific research for integrated coastal management: the Mondego estuary as study case

    Costa, Sonia; Azeiteiro, Ulisses; Pardal, Miguel

    2013-01-01

    The present paper quantifies and summarizes the research performed in the Mondego estuary (Portugal) over the last decades. Online databases were used to quantitatively assess the international publications, the master dissertations and PhD theses focused in the research about that estuary, from 1989 to 2012. In general, there had been a notable growth trend in publication output. Estuarine, Coastal and Shelf Science was the most active journal publishing on Mondego estuary. Field studies wer...

  18. Response of Nereis diversicolor population (Polychaeta, Nereididae) to the pollution impact - Authie and Seine estuaries (France)

    Gillet, P.; Mouloud, M.; Durou, C.; Deutsch, B.

    2008-01-01

    A survey within the French National Programme of Ecotoxicology was carried out in 2002, 2003 and 2004 to study the response of Nereis diversicolor populations (Polychaeta, Nereididae) to the impact of pollution in the Authie estuary (non-contaminated site) and in the Seine estuary (contaminated site). In the period studied, the density varied from 672 ind. m -2 to 3584 ind. m -2 in the Authie estuary and from 80 ind. m -2 to 920 ind. m -2 in the Seine estuary. Biomass varied from 3.94 g m -2 (dry weight) in February 2004 to 38.0 g m -2 in August 2003 in the Authie estuary and from 3.4 g m -2 in February 2002 to 0.6 g m -2 in February 2004 in the Seine estuary. Density and biomass of the populations of N. diversicolor were consistently lower in the Seine estuary than in the Authie estuary. Size frequency histograms permit the analysis of the cohorts as well as the elaboration of the growth curves. For the individuals from the Authie estuary, the relation between dry weight (DW) and length L3 (prostomium, peristomium and chaetiger 1) was DW = 4.2205 L3 2.9832. For those from the Seine estuary, the relation between dry weight and L3 was DW = 0.4697e 1.7209L3. The individuals of N. diversicolor should belong to eight cohorts in Authie estuary (two cohorts each year) instead of six cohorts for those from the Seine estuary. These differences can be attributed to the effect of pollution on the population of N. diversicolor.

  19. Thermal impact assessment of multi power plant operations on estuaries

    The assessment of the thermal impact of multi power plant operations on large estuaries requires careful consideration of the problems associated with: re-entrainment, re-circulation, thermal interaction, delay in the attainment of thermal equilibrium state, and uncertainty in specifying open boundaries and open boundary conditions of the regions, which are critically important in the analysis of the thermal conditions in receiving water bodies with tidal dominated, periodically reversing flow conditions. The results of an extensive study in the Hudson River at Indian Point, 42 miles upstream of the ocean end at the Battery, concluded that the tidal-transient, multi-dimensional discrete-element (UTA) thermal transport models (ESTONE, FLOTWO, TMPTWO computer codes) and the near-field far-field zone-matching methodology can be employed with a high degree of reliability in the assessment of the thermal impact of multi power plant operations on tidal dominated estuaries

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

    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

  1. Modeling centuries of estuarine morphodynamics in the Western Scheldt estuary

    Dam, G.; Wegen, M.; Labeur, R. J.; Roelvink, D.

    2016-04-01

    We hindcast a 110 year period (1860-1970) of morphodynamic behavior of the Western Scheldt estuary by means of a 2-D, high-resolution, process-based model and compare results to a historically unique bathymetric data set. Initially, the model skill decreases for a few decades. Against common perception, the model skill increases after that to become excellent after 110 years. We attribute this to the self-organization of the morphological system which is reproduced correctly by the numerical model. On time scales exceeding decades, the interaction between the major tidal forcing and the confinement of the estuary overrules other uncertainties. Both measured and modeled bathymetries reflect a trend of decreasing energy dissipation, less morphodynamic activity, and thus a more stable morphology over time, albeit that the estuarine adaptation time is long (approximately centuries). Process-based models applied in confined environments and under constant forcing conditions may perform well especially on long (greater than decades) time scales.

  2. STUDY OF RED TIDE PREDICTION MODEL FOR THE CHANGJIANG ESTUARY

    2000-01-01

    This paper based on field data (on red tide water quality monitoring at the Changjiang 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.

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

    刘新成; 沈焕庭

    2001-01-01

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

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

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

    2013-01-01

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

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

    2000-01-01

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

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

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

    and ultimately dead zones in the estuary. Fish mortality caused by natural and anthropogenic hypoxia has been reported in several coastal and estuarine waters and bays since 1900 (Diaz and Rosenberg 2008; Broszeit et al., 2013). Depending on the fish species..., or approximately 30% saturation) is emerging as a major threat to coastal ecosystems globally. More than 600 coastal and estuarine sites globally have developed hypoxia (Nixon, 2009; Diaz et al., 2010; Conley et al., 2011) which is an increase of approximately 5...

  7. Lateral variability of sediment transport in the Delaware Estuary

    McSweeney, Jacqueline M.; Chant, Robert J.; Sommerfield, Christopher K.

    2016-01-01

    Lateral processes contribute significantly to circulation and material transport in estuaries. The mechanisms controlling transport may vary spatially such that shallow and deep regions of an estuary contribute differently to the total transport. An observational study was conducted to explore the importance of lateral variability in sediment transport mechanisms in the Delaware Estuary. Seven moorings were deployed across the channel in the region of the estuarine turbidity maximum (ETM) zone from April to August 2011. Time series of along-channel sediment transport reveal a consistent pattern of sediment export across the entire estuary during periods of high river discharge, followed by a transition to import within the channel and export on the flanks during low river flow. There is a persistent divergence of across-channel sediment fluxes on the Delaware side, where sediment from the flank is transported toward both the channel and wetland coast. Decomposition of the fluxes highlight that across-channel sediment transport is driven by mean lateral circulation, whereas along-channel transport is driven primarily by mean advection, with tidal pumping contributing to about 30% of total transport. The spatial and temporal variability of mean advection and tidal pumping were generally complementary, with both contributing to the observed sediment transport pathways. Tidal pumping, linked to tidal asymmetries in stratification and sediment resuspension, was shown to drive both ebb-driven export and flood-driven import depending on the tidal variability of stratification. The spatiotemporal patterns of sediment transport highlight the three-dimensional structure of the ETM and shed light on the variability of sediment transport mechanisms.

  8. Possible estuary-associated syndrome: symptoms, vision, and treatment.

    Shoemaker, R C; Hudnell, H.K.

    2001-01-01

    The human illness designated as possible estuarine-associated syndrome (PEAS) by the Centers for Disease Control and Prevention (CDC) has been associated with exposure to estuaries inhabited by toxin-forming dinoflagellates, including members of the fish-killing toxic Pfiesteria complex (TPC), Pfiesteria piscicida and Pfiesteria shumwayae. Humans may be exposed through direct contact with estuarine water or by inhalation of aerosolized or volatilized toxin(s). The five cases reported here dem...

  9. 5.04 - Carbon Dioxide and Methane Dynamics in Estuaries

    Borges, Alberto; Abril, Gwenaël

    2011-01-01

    Estuaries profoundly transform the large amounts of carbon delivered from rivers before their transfer to the adjacent coastal zone. As a consequence of the complex biogeochemical reworking of allochthonous carbon in the sediments and the water column, CO2 and CH4 are emitted into the atmosphere. We attempt to synthesize available knowledge on biogeochemical cycling of CO2 and CH4 in estuarine environments, with a particular emphasis on the exchange with the atmosphere. Unlike CH4, the global...

  10. Hidrodynamics influence assessment on Mondego Estuary eutrophication process

    Duarte, António A. L. Sampaio; Pinho, José L. S.; Pardal, Miguel A. C.; Neto, João M.; Vieira, J. M. Pereira; Santos, Fernando S.

    2002-01-01

    The south arm of Mondego estuary is stressing by an eutrophication process due to massive nutrient loading from urbanised areas and diffusive runoff from intensively agricultural areas. A sampling program was carried out at three benthic sample points and at three other sites (river Pranto sluice, Armazéns channel mouth and Gala bridge) for water column monitoring. Available field data analysis allows concluding that the occurrence of green macroalgal blooms is strongly dependent on the hydro...

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

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

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

    Rao, T.V.N.

    character from highly stratified to vertically mixed types (Bowden 1977; Hass 1977; Nunes Vaz and Lennon 1987; Nu- nes Vaz 1990; Simpson et al. 1990; Nunes Vaz and Simpson 1994; Sharples et al. 1994). Because of anomalous tidal characteristics, the Gauthami...-Godavari estuary provides opportunities to examine the development of estuarine stratifi- cation and the accompanying dynamics. Increased exchange between surface and bottom water re- sults in an increase in the potential energy of the system and the generation...

  13. Water quality modelling of the western Scheldt estuary

    Ouboter, M.R.L.; Van Eck, B.T.M.; Van Gils, J.A.G.; Sweerts, J.P.; Villars, M.T.

    1998-01-01

    1n 1987 the National Institute for Coastal and Marine Management (the Netherlands) initiated the SAWES project (Systems Analysis WEstern Scheldt). The main goals of the project were to acquire knowledge with respect to the pollution problems in the Scheldt estuary and to apply this knowledge to management issues of the Scheldt on an operational level. The main interest was to understand quantitatively the relation between inputs of polluting substances and effects on the ecosystem. In the fra...

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

    Steve J. Jordan; Darrin D. Dantin; Steven P. Ferraro; Timothy G. O’Higgins; Marnita M. Chintala

    2010-01-01

    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 recr...

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

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

  16. Seasonal dynamics of turbidity maximum in the Muthupet estuary, India

    Priya, K. L.; Jegathambal, P.; James, E. J.

    2015-10-01

    Results are presented of the longitudinal and vertical profiling of salinity and suspended particulate matter (SPM) at the Muthupet estuary, India, during a one year period under widely varying freshwater flow conditions. Freshwater flow was available during post-monsoon and monsoon. An up-estuary shift in the location of estuarine turbidity maxima (ETM) was observed during the transition from post-monsoon to pre-monsoon and further it shifted downstream during the transition from pre-monsoon to monsoon, thereby exhibiting a pronounced seasonal cycle. The salinity intrusion was dependent on the freshwater discharge and was expressed as a power function of freshwater flow, explaining 97% of the variance. The formation of a salt plug in Muthupet estuary and its seasonal dynamics were observed, which is not an identified feature of any of the Indian estuaries studied so far. The geographical positions of salt plug and ETM core were more or less the same during their formation. The occurrence of two ETM during the LW of post-monsoon and the absence of ETM during monsoon explains the strong seasonal variation in the formation of ETM. The primary factor affecting the formation of ETM was identified as the freshwater flow over an annual cycle; the resuspension of sediments by tidal current affecting the formation on a flood/ebb cycle was secondary. The extent of shift of ETM was found to be an inverse logarithmic function of the freshwater discharge. The separation between ETM intrusion and salinity intrusion increased two fold with the increase in ETM intrusion.

  17. Retail Demand Response in Southwest Power Pool

    Bharvirkar, Ranjit; Heffner, Grayson; Goldman, Charles

    2009-01-30

    In 2007, the Southwest Power Pool (SPP) formed the Customer Response Task Force (CRTF) to identify barriers to deploying demand response (DR) resources in wholesale markets and develop policies to overcome these barriers. One of the initiatives of this Task Force was to develop more detailed information on existing retail DR programs and dynamic pricing tariffs, program rules, and utility operating practices. This report describes the results of a comprehensive survey conducted by LBNL in support of the Customer Response Task Force and discusses policy implications for integrating legacy retail DR programs and dynamic pricing tariffs into wholesale markets in the SPP region. LBNL conducted a detailed survey of existing DR programs and dynamic pricing tariffs administered by SPP's member utilities. Survey respondents were asked to provide information on advance notice requirements to customers, operational triggers used to call events (e.g. system emergencies, market conditions, local emergencies), use of these DR resources to meet planning reserves requirements, DR resource availability (e.g. seasonal, annual), participant incentive structures, and monitoring and verification (M&V) protocols. Nearly all of the 30 load-serving entities in SPP responded to the survey. Of this group, fourteen SPP member utilities administer 36 DR programs, five dynamic pricing tariffs, and six voluntary customer response initiatives. These existing DR programs and dynamic pricing tariffs have a peak demand reduction potential of 1,552 MW. Other major findings of this study are: o About 81percent of available DR is from interruptible rate tariffs offered to large commercial and industrial customers, while direct load control (DLC) programs account for ~;;14percent. o Arkansas accounts for ~;;50percent of the DR resources in the SPP footprint; these DR resources are primarily managed by cooperatives. o Publicly-owned cooperatives accounted for 54percent of the existing DR resources

  18. Leaf litter ecological fate in the Schelde estuary in Belgium

    2002-01-01

    Two dominant species of Willow (Salix triandra) and Reed(Phragmites australis) along the Schelde estuary (in Belgium) wereselected in this research. The pigments of higher plant was used asbiomarkers, the decomposition process of the two species werestudied after they fall into the Schelde estuary. After statisticalanalysis (Spearman rank order correlation, p<0.05), the results hasshown the decomposition dynamics pattern of the pigments, and thewillow showed different pattern in comparing with the reed, eg.Chlorophyll-a decomposition dynamics for willow is: y1 = 12196x2 -175895x + 1E + 06 + k, R2 = 0.5706 while for reed is: y2 = -37878x2+ 229782x + 734282 + k, R2 = 0.9065. The precise time of the leaflitter spent in the water was also calculated as were less than 24days, 24-37 days, longer than 37 days (willow) and less than 24days, longer than 24 days (reed), the leaf litter fate of the two -Process, Institute of Applied Ecology, Chinese Academy of Sciencesdominant species in the Schelde estuary was also compared.

  19. Dissolved oxygen conditions in northern Gulf of Mexico estuaries

    Engle, V.D.; Kevin, Summers J.; Macauley, J.M.

    1999-01-01

    Because deficient dissolved oxygen (DO) levels may have severe detrimental effects on estuarine and marine life, DO has been widely used as an indicator of ecological conditions by environmental monitoring programs. The U.S. EPA's Environmental Monitoring and Assessment Program for Estuaries (EMAP-E) monitored DO conditions in the estuaries of the Gulf of Mexico from 1991 to 1994. DO was measured in two ways: 1)instantaneous profiles from the surface to the bottom were taken during the day, and 2) continuous measurements were taken near the bottom at 15 min intervals for at least 12 h. This information was summarized to assess the spatial distribution and severity of DO conditions in these estuaries. Depending on the criteria used to define hypoxia (DO concentrations usually < 2 mg L-1 or 15 mg L-1) and the method by which DO is measured, we estimate that between 5.2 and 29.3% of the total estuarine area in the Louisianian Province was affected by low DO conditions.

  20. Major hydrogeochemical processes in an Acid Mine Drainage affected estuary

    Highlights: • Mixing of acid riverine water with alkaline seawater was studied in an estuary. • Combination of data and geochemical tools allowed modeling the water mixing. • The main geochemical processes were identified and for the first time quantified. • Water chemistry is the result of mixing, dissolution-precipitation and sorption. • Main reactions: gypsum and calcite dissolution and Al and Fe solids precipitation. - Abstract: 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)

  1. 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...

  2. 2005/2006 Southwest Florida Water Management District (SWFWMD) Lidar: Peace River South (including Carter Creek)

    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. Landscape practices and representations in eighteenth-century Dongchuan, Southwest China

    Huang, Fei

    2012-01-01

    My doctorial thesis, entitled ‘Landscape Practices and Representations in Dongchuan, Southwest Eighteenth-Century China’, focuses on the interdisciplinary study of landscape, space and architecture in Southwest eighteenth-century China. Through intensive archival research and contemporary ethnograph

  4. 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...

  5. 'FLYING UNDER RADAR': SOUTHWEST AIRLINES AND INCUMBENTS¡¯ RESPONSE TO ENTRY

    Jun-Byoung Oh

    2006-01-01

    This paper investigates the competitive effect of Southwest Airlines, considering the factors affecting its decision to offer service in particular city-pairs and the effect of Southwest¡¯s presence on overall fares and the fare distribution of major airlines. Southwest is a formidable, apparently low-cost competitor when it is present it often garners a large share and creates significant fare pressure on major airlines. Despite this competitive success Southwest¡¯s network does not include ...

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

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

    Institute of Oceanography, Dona Paula, Goa 403004, India Received 26 August 2007; accepted 29 January 2008 Available online 10 February 2008 Abstract Bacterial productivity (BP) and respiration (BR) were examined in relation to primary productivity (PP... the C-cycling in this estuary. These results are of particular relevance to tropical ecosystems in general, where the bulk of world’s river discharges occur. C211 2008 Elsevier Ltd. All rights reserved. Keywords: primary productivity; bacterial...

  7. Residual fluxes of water and nutrient transport through the main inlet of a tropical estuary, Cochin estuary, West Coast, India

    Vinita, J.; Lallu, K.R.; Revichandran, C.; Muraleedharan, K.R.; Jineesh, V.K.; Shivaprasad, A.

    . The strong ebb currents and the increased nutrient concentrations during ebb resulted in the export of all nutrients (except ammonia during spring) into the sea. The findings of this study highlight the consequences of anthropogenic interventions...., Greenberg, A. E., et al. (Eds.), Washington, DC: American Public Health Association. Balachandran, K.K., Laluraj, C.M., Nair, M., Joseph, T., Sheeba, P., et al. (2005). Heavy metal accumulation in a flow restricted tropical estuary. Estuarine, Coastal...

  8. Propagation of tides in the Mandovi and Zuari estuaries

    Shetye, S.R.

    of riverine freshwater during the southwest monsoon and little during the rest of the year. Tides in the channels exhibit the following characteristics: (a) The speed of propagation is about 6.5 ms sup(-1); (b) tidal amplitude remains unchanged over a distance...

  9. Three-dimensional semi-idealized model for tidal motion in tidal estuaries. An application to the Ems estuary

    Kumar, Mohit; Schuttelaars, Henk M.; Roos, Pieter C.; Möller, Matthias

    2016-01-01

    In this paper, a three-dimensional semi-idealized model for tidal motion in a tidal estuary of arbitrary shape and bathymetry is presented. This model aims at bridging the gap between idealized and complex models. The vertical profiles of the velocities are obtained analytically in terms of the first-order and the second-order partial derivatives of surface elevation, which itself follows from an elliptic partial differential equation. The surface elevation is computed numerically using the finite element method and its partial derivatives are obtained using various methods. The newly developed semi-idealized model allows for a systematic investigation of the influence of geometry and bathymetry on the tidal motion which was not possible in previously developed idealized models. The new model also retains the flexibility and computational efficiency of previous idealized models, essential for sensitivity analysis. As a first step, the accuracy of the semi-idealized model is investigated. To this end, an extensive comparison is made between the model results of the semi-idealized model and two other idealized models: a width-averaged model and a three-dimensional idealized model. Finally, the semi-idealized model is used to understand the influence of local geometrical effects on the tidal motion in the Ems estuary. The model shows that local convergence and meandering effects can have a significant influence on the tidal motion. Finally, the model is applied to the Ems estuary. The model results agree well with observations and results from a complex numerical model.

  10. Collection Development "Southwest Gardening": The Desert Shall Bloom

    Charles, John; Mosley, Shelley; Van Winkle, Sandra

    2008-01-01

    Gardening in the American Southwest (SW) is an extreme sport. Not only are gardeners challenged by geographic extremes from tropical deserts to subalpine locales, they must also deal with a wide range of climates. Winter in the mountains and higher regions means heavy snows, frozen soils, and temperatures that can dip below zero. In contrast,…

  11. FACTS AND IRONIES OF THE WATER SITUATION IN THE SOUTHWEST.

    KNOWLTON, CLARK S.

    THE SOUTHWEST IS SEEN AS A REGION LONG DOMINATED BY RANCHING, MINING, AND IRRIGATED AGRICULTURE. RAPID URBANIZATION AND INDUSTRIALIZATION IS RESULTING IN WATER PROBLEMS SIGNIFICANT TO A SOCIOCULTURAL AND A PHYSICAL ENVIRONMENT. THE FIRST GROUP OF PROBLEMS IS CHARACTERIZED BY INDIFFERENCES TO DROUGHT AND WATER DEPLETION POTENTIAL SINCE WATER USERS…

  12. [Temporal and spatial distribution of rice drought in Southwest China].

    Zhang, Jian-ping; Liu, Zong-yuan; He, Yong-kun; Luo, Hong-xia; Wang, Jing

    2015-10-01

    Considering the characteristics of rice production and climate conditions in Southwest China, an agricultural drought monitoring model based on wetness index anomaly rate (Mp) by calculating the variation of deviation from average values of relative humid index was established, and was used to analyze the spatial-temporal distribution characteristics of the rice drought during the growth season in Southwest China in the past 50 years (1961-2010). The applicability of the Mp model in Southwest China was verified by using this model to monitor the rice drought. The result showed there was a decreasing trend in the frequency of rice drought in term of the decadal variability. The areas with high drought risk mainly concentrated in northwestern and mid-eastern Yunnan Province, eastern Sichuan Basin, northeastern Chongqing City, and southeastern Guizhou Province. The drought frequency was highest at the stage from transplanting to tasseling, followed by the stage from grain filling to maturity, and was lowest at the stage from tasseling to grain filling. Mp was suitable for monitoring the rice drought in Southwest China, and could be used as a reference for the rice planting areas without irrigation data. PMID:26995919

  13. A Joint Lab Against Viral Diseases Created in Southwest China

    2004-01-01

    @@ With approval of the CAS Steering Committee for Research Bases in Southwest China, a laboratory devoted to the development of natural anti-virus medicines is to be set up under the joint sponsorship of the CAS Kunming Institute of Botany (KIB)and the CAS Kunming Institute of Zoology (KIZ).

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

    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.

  15. Land use and nitrogen loading in seven estuaries along the southern Gulf of St. Lawrence, Canada

    McIver, Reba; Milewski, Inka; Lotze, Heike K.

    2015-11-01

    Nitrogen loading from coastal watersheds is a principal factor associated with the decline in eelgrass bed health and cover in estuaries worldwide. We apply the Nitrogen Loading Model (NLM) framework developed in Waquoit Bay, Massachusetts to 7 estuaries in eastern New Brunswick. Using watershed-specific information on human population, wastewater production, atmospheric deposition, and land use in each watershed we estimate annual input of Total Dissolved Nitrogen (TDN) from point and non-point sources. We also estimate flushing time of each estuary using available hydrodynamic and bathymetric data incorporated in a tidal prism model. Finally, we validate the NLM results by testing the link between estimated nitrogen loading, flushing time and nitrogen signals in eelgrass tissue including nitrogen content and stable isotopes. Overall, total nitrogen load (kg TDN yr-1) was strongly dependent on watershed and estuary size, while loading rate per unit watershed area (yield) was linked to watershed population density. Atmospheric deposition was the largest contributor of nitrogen to all estuaries except one, where seafood processing effluent was the greatest source. Stable isotope analysis of eelgrass tissue reflected this distinction, with high δ15N values of 8-10‰ related to high wastewater loading, compared to 2-6.5‰ in the other estuaries that receive proportionally more atmospheric deposition. Tissue nitrogen content was positively related to nitrogen yields and loading rate per volume of estuary, highlighting the influence of variable watershed:estuary size ratio. Multiple regression analysis identified a significant interaction between nitrogen yield and flushing time on eelgrass tissue nitrogen content and isotopes, pointing to the mitigating effect an estuary's quick flushing time can have on the expression of nitrogen enrichment in primary producers. The compilation of new information on nitrogen loading to east Canadian estuaries is a novel

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

    Lund-Hansen, Lars Chresten; Hai, Doan Nhu; Lam, Nguyen Ngoc; Nielsen, Morten Holtegaard

    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 prope...... 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....

  17. The dynamics of a frictionally-dominated Amazonian estuary

    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 por

  18. Technology-critical elements: a need for evaluating the anthropogenic impact on their marine biogeochemical cycles

    Antonio Cobelo-Garcia

    2014-06-01

    (ii Pt behaviour during estuarine mixing. The factors controlling the behaviour of Pt during estuarine mixing and its particle–water interactions will be discussed from the data obtained in the Lérez Estuary (NW Iberian Peninsula and the Gironde Estuary (SW France, with the implication for its transport and fate in the coastal ocean.

  19. Monsoons and habitat influence trophic pathways and the importance of terrestrial-marine linkages for estuary sharks

    Yeung, JWY; Lam, VYY; Williams, GA; Wai, TC; Leung, KMY; Dudgeon, D

    2012-01-01

    Tropical estuaries often receive enhanced fluxes of terrestrial derived organic matter and phytoplankton during the wet season, and such monsoonal events may significantly influence the trophic dynamics of these systems. This study examined spatio-temporal terrestrial-marine linkages in a tropical estuary, the Pearl River Estuary (PRE), southern China, by investigating trophic pathways leading to estuary sharks. We investigated spatial (inshore vs. offshore) and seasonal (wet vs. dry season) ...

  20. Dramatic Demand Reduction In The Desert Southwest

    Boehm, Robert [Univ. of Nevada, Las Vegas, NV (United States); Hsieh, Sean [Univ. of Nevada, Las Vegas, NV (United States); Lee, Joon [Univ. of Nevada, Las Vegas, NV (United States); Baghzouz, Yahia [Univ. of Nevada, Las Vegas, NV (United States); Cross, Andrew [Univ. of Nevada, Las Vegas, NV (United States); Chatterjee, Sarah [NV Energy, Las Vegas, NV (United States)

    2015-07-06

    This report summarizes a project that was funded to the University of Nevada Las Vegas (UNLV), with subcontractors Pulte Homes and NV Energy. The project was motivated by the fact that locations in the Desert Southwest portion of the US demonstrate very high peak electrical demands, typically in the late afternoons in the summer. These high demands often require high priced power to supply the needs, and the large loads can cause grid supply problems. An approach was proposed through this contact that would reduce the peak electrical demands to an anticipated 65% of what code-built houses of the similar size would have. It was proposed to achieve energy reduction through four approaches applied to a development of 185 homes in northwest part of Las Vegas named Villa Trieste. First, the homes would all be highly energy efficient. Secondly, each house would have a PV array installed on it. Third, an advanced demand response technique would be developed to allow the resident to have some control over the energy used. Finally, some type of battery storage would be used in the project. Pulte Homes designed the houses. The company considered initial cost vs. long-term savings and chose options that had relatively short paybacks. HERS (Home Energy Rating Service) ratings for the homes are approximately 43 on this scale. On this scale, code-built homes rate at 100, zero energy homes rate a 0, and Energy Star homes are 85. In addition a 1.764 Wp (peak Watt) rated PV array was used on each house. This was made up of solar shakes that were in visual harmony with the roofing material used. A demand response tool was developed to control the amount of electricity used during times of peak demand. While demand response techniques have been used in the utility industry for some time, this particular approach is designed to allow the customer to decide the degree of participation in the response activity. The temperature change in the residence can be decided by the residents by

  1. Dramatic Demand Reduction In The Desert Southwest

    Boehm, Robert [Univ. of Nevada, Las Vegas, NV (United States); Hsieh, Sean [Univ. of Nevada, Las Vegas, NV (United States); Lee, Joon [Univ. of Nevada, Las Vegas, NV (United States); Baghzouz, Yahia [Univ. of Nevada, Las Vegas, NV (United States); Cross, Andrew [Univ. of Nevada, Las Vegas, NV (United States); Chatterjee, Sarah [NV Energy, Las Vegas, NV (United States)

    2015-07-06

    This report summarizes a project that was funded to the University of Nevada Las Vegas (UNLV), with subcontractors Pulte Homes and NV Energy. The project was motivated by the fact that locations in the Desert Southwest portion of the US demonstrate very high peak electrical demands, typically in the late afternoons in the summer. These high demands often require high priced power to supply the needs, and the large loads can cause grid supply problems. An approach was proposed through this contact that would reduce the peak electrical demands to an anticipated 65% of what code-built houses of the similar size would have. It was proposed to achieve energy reduction through four approaches applied to a development of 185 homes in northwest part of Las Vegas named Villa Trieste. First, the homes would all be highly energy efficient. Secondly, each house would have a PV array installed on it. Third, an advanced demand response technique would be developed to allow the resident to have some control over the energy used. Finally, some type of battery storage would be used in the project. Pulte Homes designed the houses. The company considered initial cost vs. long-term savings and chose options that had relatively short paybacks. HERS (Home Energy Rating Service) ratings for the homes are approximately 43 on this scale. On this scale, code-built homes rate at 100, zero energy homes rate a 0, and Energy Star homes are 85. In addition a 1.764 Wp (peak Watt) rated PV array was used on each house. This was made up of solar shakes that were in visual harmony with the roofing material used. A demand response tool was developed to control the amount of electricity used during times of peak demand. While demand response techniques have been used in the utility industry for some time, this particular approach is designed to allow the customer to decide the degree of participation in the response activity. The temperature change in the residence can be decided by the residents by

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

    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 ...

  3. Water pollution in estuaries and coastal zones. (Latest citations from the NTIS bibliographic database). Published Search

    NONE

    1996-02-01

    The bibliography contains citations concerning the studies of water pollution in estuaries and coastal zones. Citations examine the development, management, and protection of estuary and coastal resources. Topics include pollution sources, environmental monitoring, water chemistry, eutrophication, models, land use, government policy, and laws and regulations. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

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

    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.

  5. The nature and distribution of particulate matter in the Mandovi Estuary, central west coast of India

    Kessarkar, P.M.; Rao, V.P.; Shynu, R.; Mehra, P.; Viegas, B.E.

    and biogenic particles occur everywhere in the estuary. Diatoms are the most common and are of marine type at the sea-end and freshwater dominated at river-end stations of the estuary. SPM is characterized by kaolinite- and smectite-rich clay mineral suites...

  6. Benthic macrofaunal dynamics and environmental stress across a salt wedge Mediterranean estuary.

    Nebra, Alfonso; Alcaraz, Carles; Caiola, Nuno; Muñoz-Camarillo, Gloria; Ibáñez, Carles

    2016-06-01

    The spatial distribution of benthic macroinvertebrate community in relation to environmental factors was studied along the Ebro Estuary (NE Iberian Peninsula), a salt wedge Mediterranean estuary. Both ordination methods and generalized additive models were performed to identify the different benthic assemblages and their relationship to abiotic factors. Our results showed a strong relationship between macrofaunal assemblages and the predominant environmental gradients (e.g. salinity); thus revealing spatial differences in their structure and composition. Two different stretches were identified, namely the upper (UE) and the lower Ebro Estuary (LE). UE showed riverine characteristics and hence was colonized by a freshwater community; whereas LE was influenced by marine intrusion and sustained a complex marine-origin community. However, within each stretch, water and sediment characteristics played an important role in explaining species composition differences among sampling stations. Moreover, outcomes suggested a total species replacement pattern, instead of the nestedness pattern usually associated with well-mixed temperate estuaries. The sharp species turnover together with the estuarine stratification point out that the Ebro Estuary is working, in terms of ecological boundaries, under an ecotone model. Finally, despite obvious differences with well mixed estuaries (i.e. lack of tidal influence, stratification and species turnover), the Ebro Estuary shares important ecological attributes with well-mixed temperate estuaries. PMID:27062106

  7. Concentration and Distribution of Hydrophobic Organic Contaminants and Metals in the Estuaries of Ukraine

    In this baseline study of Ukrainian estuaries, sediments and organisms from the Dnieper and Boh estuaries and Danube Delta on the mainland, Sevastopol and Balaklava Bays on the Crimean Peninsula, and coastal Black Sea along the Crimean Peninsula were collected in 2006. Contamina...

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

    2011-02-14

    ... including water withdrawals, flow regulation, natural climate cycles, and human contributions to global... the estuary and plume have also degraded water quality. Contaminants found in the estuary and plume... throughout the entire life cycle. The salmonid life cycle includes spawning and rearing in the...

  9. Modelling the transverse distribution of velocity and suspended sediment in tidal estuaries

    Huijts, K.M.H.

    2011-01-01

    An estuary is a semi-enclosed coastal body of water which has a free connection with the open sea and within which sea water is measurably diluted with fresh water derived from land drainage. Examples are the Western Scheldt River Estuary and the Chesapeake Bay. Within these environments complex pat

  10. The effects of changes to estuarine hydrology on system phosphorous retention capacity: The Mondego estuary, Portugal

    Lillebo, A. I.; Otero, M.; Coelho, J. P.;

    2012-01-01

    The Mondego estuary is a mainly polyhaline estuary in central Portugal in which eutrophication increased during the last decades of the 20th century. In 1998 the system hydrology was changed, aiming to reverse the eutrophication process. A long environmental monitoring database showed that the me...

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

    Shetye, S.R.; Vijith, V.

    at periods longer than two days. We then examine the causes behind the variability using data on wind and current measured near the mouth of the estuary. The main channel of the estuary is 50 km long and March–April is a period when local winds are weak. Our...

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

    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.

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

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

  14. Estuary Data Mapper: A virtual portal to coastal data informing environmental management decisions

    The Estuary Data Mapper (EDM) is a free, interactive graphical application under development at the US EPA that allows environmental researchers and managers to quickly and easily retrieve, view and save subsets of online US coastal estuary-related data. Accessible data include ...

  15. Residual estuarine circulation in the Mandovi, a monsoonal estuary: A three-dimensional model study

    Vijith, V.; Shetye, S. R.; Baetens, K.; Luyten, P.; Michael, G. S.

    2016-05-01

    Observations in the Mandovi estuary, located on the central west coast of India, have shown that the salinity field in this estuary is remarkably time-dependent and passes through all possible states of stratification (riverine, highly-stratified, partially-mixed and well-mixed) during a year as the runoff into the estuary varies from high values (∼1000 m3 s-1) in the wet season to negligible values (∼1 m3 s-1) at end of the dry season. The time-dependence is forced by the Indian Summer Monsoon (ISM) and hence the estuary is referred to as a monsoonal estuary. In this paper, we use a three-dimensional, open source, hydrodynamic, numerical model to reproduce the observed annual salinity field in the Mandovi. We then analyse the model results to define characteristics of residual estuarine circulation in the Mandovi. Our motivation to study this aspect of the Mandovi's dynamics is derived from the following three considerations. First, residual circulation is important to long-term evolution of an estuary; second, we need to understand how this circulation responds to strongly time-dependent runoff forcing experienced by a monsoonal estuary; and third, Mandovi is among the best studied estuaries that come under the influence of ISM, and has observations that can be used to validate the model. Our analysis shows that the residual estuarine circulation in the Mandovi shows four distinct phases during a year: a river like flow that is oriented downstream throughout the estuary; a salt-wedge type circulation, with flow into the estuary near the bottom and out of the estuary near the surface restricted close to the mouth of the estuary; circulation associated with a partially-mixed estuary; and, the circulation associated with a well-mixed estuary. Dimensional analysis of the field of residual circulation helped us to establish the link between strength of residual circulation at a location and magnitude of river runoff and rate of mixing at the location. We then

  16. Distribution and sources of aliphatic hydrocarbons and fatty acids in surface sediments of a tropical estuary south west coast of India (Cochin estuary)

    Gireeshkumar, T.R.; Deepulal, P.M.; Chandramohanakumar, N.

    Surface sediments samples from the Cochin estuary were measured for elemental, stable isotopic and molecular biomarkers (aliphatic hydrocarbons and fatty acids) to study the sources and distribution of sedimentary organic matter. Concentrations...

  17. Dissolved organic matter (DOM) export to a temperate estuary: Seasonal variations and implications of land use

    Stedmon, C. A.; Markager, S.; Søndergaard, M.;

    2006-01-01

    Inputs of dissolved carbon, nitrogen, and phosphorus were assessed for an estuary and its catchment (Horsens, Denmark). Seasonal patterns in the concentrations of DOM in the freshwater supply to the estuary differed depending on the soil and drainage characteristics of the area. In streams draining......, and the percentage of catchment area used for agriculture. Colored DOM (CDOM) loading measurements were found to be a good predictor of dissolved organic carbon (DOC) loading across the different subcatchments, offering a rapid and inexpensive alternative of operationally monitoring DOC export. For...... all the dissolved nutrient inputs to the estuary, dissolved inorganic nitrogen (DIN) and dissolved organic phosphorus dominated the loadings. Although 81% of the nitrogen annually supplied to the estuary was DIN, 83% of the nitrogen exported from the estuary was dissolved organic nitrogen (DON...

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

    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.

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

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

    2016-03-01

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

  20. Feeding preferences of estuarine mysids Neomysis integer and Rhopalophthalmus tartessicus in a temperate estuary (Guadalquivir Estuary, SW Spain)

    Vilas, C.; Drake, P.; Fockedey, N.

    2008-01-01

    Mysid shrimps are an important component of estuarine food webs because they play a key role in energy transfer as intermediate prey. We investigated the seasonal, tidal and depth specific variation in the diet of the estuarine mysids Neomysis integer and Rhopalophthalmus tartessicus and explored its implications for the planktonic community structure of a temperate estuary (Guadalquivir Estuary, SW Spain). Neomysis integer is an opportunistic omnivore feeding mainly on mesozooplankton and on...

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

    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

  2. Morphodynamic evolution of the Xiaoqing River mouth:a Huanghe River-derived mixed energy estuary

    HUANG Haijun; LIU Yanxia; QIU Zhongfeng

    2012-01-01

    In an estuary,tidal,wave and other marine powers interact with the coast in different ways and affect estuary morphology as well as its evolution.In the Huanghe(Yellow)River estuaries and nearby delta,there are many small sediment-affected estuaries with a unique morphology,such as the Xiaoqing River estuary.In this study,we investigated the special evolution and genetic mechanism of the Xiaoqing River estuary by analyzing graphic and image data with a numerical simulation method.The results show that NE and NE-E tide waves are the main driving force for sandbar formation.Sediment shoals have originated from huge amounts of sediment from the Huanghe River,with consequent deposition at the Xiaoqing River mouth.The lateral suspended sediments beyond the river mouth move landward.Siltation takes place on the northern shoreline near the river mouth whereas erosion occurs in the south.The deposits come mainly from scouring of the shallow seabed on the northern side of the estuary.Storm surges speed up deposition in the estuary.Development of the sediment shoals has occurred in two steps involving the processes of growth and further southward extension.Although the southward shift increases the river curvature and length,the general eastward orientation of the estuary is unlikely to change.Processes on the adjacent shorelines do not affect the development of the sediment shoals.The study presents a morphodynamic evolutionary model for the Xiaoqing River estuary,with a long-term series cycle,within which a relatively short cycle occurs.

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

    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…

  4. The main phosphorous sources in the Changjiang estuary

    YANG Dongfang; WANG Fan; MIAO Zhenqing; CHEN Yongli; TONG Yuanzheng

    2008-01-01

    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 32°N Upwelling < the cyclone-type eddy, and the duration of the supplying was: 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 μmol/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.

  5. Occurrence of Anaerobic Ammonium Oxidation in the Yangtze Estuary

    Hou, L.

    2013-12-01

    Over the past several decades, a large quantity of reactive nitrogen has been transported into the Yangtze estuarine and coastal water, due to intense human activities in the Yangtze River Basin. At present, it annually receives a high load of anthropogenic inorganic nitrogen (about 1.1 × 1011 mol N) from increased agricultural activities, fish farming, and domestic and industrial wastewater discharge in the Yangtze River Basin, consequently leading to severe eutrophication and frequent occurrences of harmful algal blooms in the estuary and adjacent coastal areas. Hence, the microbial nitrogen transformations are of major concern in the Yangtze Estuary. Anaerobic ammonium oxidation (anammox) has been reported to play a significant role in the removal of reactive nitrogen in aquatic ecosystems. In this study, the occurrences of anammox bacteria and associated activity in the Yangtze Estuary were evidenced with molecular and isotope-tracing techniques. It is observed that the anammox bacteria at the study area mainly consisted of Candidatus Scalindua, Brocadia, Kuenenia. Salinity was found to be a key environmental factor controlling distribution and diversity of the anammox bacterial community at the estuarine ecosystem. Also, temperature and organic carbon had significant influences on anammox bacterial biodiversity. Q-PCR assays of anammox bacteria indicated that their abundance had a range of 2.63 ×106 - 9.48 ×107 copies g-1 dry sediment, with high spatiotemporal heterogeneity. The potential anammox activities measured in the present work varied between 0.94 - 6.61nmol N g-1 dry sediment h-1, which were related to temperature, nitrite and anammox bacterial abundance. On the basis of the 15N tracing experiments, the anammox process was estimated to contribute 6.6 - 12.9 % to the total nitrogen loss whereas the remainder was attributed to denitrification.

  6. Environmental monitoring of the Zhujiang Estuary and its coastal waters

    J. C. Chen(陈介中); L. Dong; L. A. Wong; G. W. Heinke

    2002-01-01

    The Zhujiang (Pearl River ) Estuary is a complex water system whose catchments basin coveers a very large part of southern China. The large quantity of fresh water carried by the river system flows into the northern coast of the South China Sea through its eight inlets. The Zhujiang River Delta has experienced the fastest economic growth in China during the past two decades. Rapid population expansion and increased industrial development coupled with insufficient waste management turned the Zhujiang Estuary into waste disposal channels just before entering the coastal waters. The water quality of the estuaries and the coastal oceans has become polluted. Dttfing the past two years, an intensive study and monitoring efforts of the pollutions of these waters have been made. A systematic and integrated monitoring task including shore-based measurements, shipboard in-situ measurements, and satellite and radar remote sensing surveys has been completed. Conprehensive collection of physical,chemical and biological parameters has been accomplished and a database has been established. Unlike the previous large scale-monitoring task in which the various pollutant concentrations were the objective,the present study aims to understand the process of the pollution from their initial disposal to their final states. The understanding of the processes makes it possible to evaluate the severity of the pollution with respect to the sustainability. Also the objective is to incorporate these processes into the mathematical models from which a predictive capability of the pollution situation can be realized. The present presentation will describe the planning, methodology and the results of this effort.

  7. Aggregate Settling Velocities in San Francisco Estuary Margins

    Allen, R. M.; Stacey, M. T.; Variano, E. A.

    2015-12-01

    One way that humans impact aquatic ecosystems is by adding nutrients and contaminants, which can propagate up the food web and cause blooms and die-offs, respectively. Often, these chemicals are attached to fine sediments, and thus where sediments go, so do these anthropogenic influences. Vertical motion of sediments is important for sinking and burial, and also for indirect effects on horizontal transport. The dynamics of sinking sediment (often in aggregates) are complex, thus we need field data to test and validate existing models. San Francisco Bay is well studied and is often used as a test case for new measurement and model techniques (Barnard et al. 2013). Settling velocities for aggregates vary between 4*10-5 to 1.6*10-2 m/s along the estuary backbone (Manning and Schoellhamer 2013). Model results from South San Francisco Bay shoals suggest two populations of settling particles, one fast (ws of 9 to 5.8*10-4 m/s) and one slow (ws of < 1*10-7 to 1.4*10-5 m/s) (Brand et al. 2015). While the open waters of San Francisco Bay and other estuaries are well studied and modeled, sediment and contaminants often originate from the margin regions, and the margins remain poorly characterized. We conducted a 24 hour field experiment in a channel slough of South San Francisco Bay, and measured settling velocity, turbulence and flow, and suspended sediment concentration. At this margin location, we found average settling velocities of 4-5*10-5 m/s, and saw settling velocities decrease with decreasing suspended sediment concentration. These results are consistent with, though at the low end of, those seen along the estuary center, and they suggest that the two population model that has been successful along the shoals may also apply in the margins.

  8. Oil spill response planning on the Columbia river estuary

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

  9. Influence of habitat structure and mouth dynamics on avifauna of intermittently-open estuaries: A study of four small South African estuaries

    Terörde, Anja I.; Turpie, Jane K.

    2013-07-01

    Habitat composition was a major factor in determining waterbird species composition and abundance, particularly the area of floodplain and vegetated channel in four intermittently open estuaries (IOEs) in the warm-temperate coastal biogeographical region of South Africa. Average bird densities on the four estuaries varied from 0.5 to 4.2 birds per hectare, and community composition differed significantly between estuaries. However, the considerable variation in abundance of macrophytes did not have a detectable effect on waterbirds. Under closed mouth conditions, piscivorous birds dominated the avifauna. Each estuary's avifauna responded differently in terms of changes in feeding guild composition when the mouth opened. Bird abundance changed immediately after breaching, but not consistently. Diversity was significantly higher under open-mouth conditions for three of the four estuaries, and species composition was significantly different from that under closed-mouth conditions at all four estuaries. Changes in mouth dynamics as a result of climate change, water abstraction and artificial breaching could lead to significant changes in estuarine fauna.

  10. Nutrient transport to the Swan-Canning Estuary, Western Australia

    Peters, Norman E.; Donohue, Robert

    2001-09-01

    Catchment nutrient availability in Western Australia is primarily controlled by the disposal of animal waste and the type and rate of fertilizer application, particularly on the relatively narrow (25 km wide), sandy coastal plain. Nitrogen (N) and phosphorus (P) concentrations and fluxes during the wet season of 15 tributaries, including four urban drains to the Swan-Canning Estuary, were evaluated from 1986 to 1992 and additionally concentrations only were evaluated throughout the year from 1993 to 1996. Concentrations of filtered reactive P (FRP) and total P (TP) were generally low, with the volume-weighted means for all sites being 0·06 mg l-1 and 0·12 mg l-1 respectively. The urban drains had higher TP concentrations (volume-weighted mean of 0·21 mg l-1) than the streams (0·12 mg l-1), with the high concentrations associated with particulate matter. Total inorganic N (TIN, NH4N plus NO3N) and total N (TN), which is of interest to eutrophic status of the N-limited estuary, were likewise low, compared with other developed areas having a similar climate. Both TIN and TN were higher in the urban drains (0·76 mg l-1 and 1·5 mg l-1 respectively) than the streams (0·31 mg l-1 and 1·2 mg l-1 respectively). The Avon River, which drains 98·5% of the 121 000 km2 catchment area, contributes most of the N (0·03 kg ha-1 year-1 or 65%) and a high percentage of the P (superphosphate and has the highest FRP (0·51 mg lestuary. The coastal plain is also undergoing urbanization, particularly in areas adjacent to the estuary. Nutrients are subsequently available for transport during the onset of seasonal wet weather. Perennial baseflow from urban areas is an important source of nutrients. Water yield from the urban areas was high, being as much as 50% of annual rainfall. The timing of the nutrients delivered by the tributaries may be an important control on estuarine ecology

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

    Barber, D.; Liquori, M.

    2010-12-01

    Despite extensive scientific advancement integrating our understanding of hydrology, geomorphology, and ecology in recent decades, the application of restoration in the field has been slow to evolve. This presentation will highlight 20 years of restoration practices in the Mattole River Estuary and how these practices have informed our understanding of this complex system. The Mattole River Watershed is a 304 square-mile basin located near the Mendocino Triple Junction in a remote region of California known as the “The Lost Coast” for its rugged mountains and undeveloped coastline. In addition to numerous species of fish, mammals, and over 250 bird species, the Mattole Watershed is home to three Federally-listed Threatened salmonids: California Coastal Chinook salmon, Southern Oregon/Northern California Coasts coho salmon, and Northern California steelhead trout. The 64 mile-long river meets the Pacific Ocean at the northern end of the 64,000 acre King Range National Conservation Area (KRNCA), managed by the Bureau of Land Management (BLM). The watershed is dynamic, with some of the nation’s highest annual rainfall (mean = 158 cm/yr), naturally occurring steep slopes, erosive sedimentary geology, and frequent earthquakes. All of these factors have amplified the negative effects of extensive logging and associated road building between 1945 and 1970, which left a legacy of increased sediment loads and high water temperatures that have yet to recover to pre-disturbance levels, severely impairing riparian and aquatic habitats. Prior to major land disturbances, the Mattole estuary/lagoon was notable for its deep, thermally-stratified pools and numerous functioning north and south bank slough channels that flushed sediments from the river and received marine water. As flows decline in late spring, a sandbar closes off surface flow from the river to the Pacific Ocean, forming a lagoon, which persists until flows increase in the fall. Today, the estuary is poor

  12. The Salt fluxes in a tidally-energetic estuary

    Simpson, J H; Vennell, R.; A. J. Souza

    2001-01-01

    Time series measurements of velocity and salinity have been used to examine the salt flux components in the tidally-energetic regime of the Conwy Estuary in North Wales. The instantaneous volume transport, up to 400 m3 s−1, was deduced from a current meter located in mid-channel using a frictional model with a correction for the observed mean velocity shear. Transport estimates obtained in this way have been compared with independent measurements of integrated cross-section transport using a ...

  13. Hydrodynamics and Water Quality: Modeling Rivers, Lakes, and Estuaries

    Opdyke, Daniel

    2008-09-01

    The modeling of lakes, rivers, and estuaries is a fascinating subject that combines interesting facets of mathematics, statistics, physics, chemistry, and biology. Because of the complexity of natural systems, such modeling is always an approximation of the real world-and sometimes not a very good one. It is for this reason that modeling is not just science but also art. It is also for this reason that there are few good texts offering practical advice on modeling. Hydrodynamics and Water Quality makes a valiant attempt but is only partially successful because of the book's narrow focus on one family of models and an inconsistent presentation.

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

    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

  15. Acid deposition and lake chemistry in southwest China

    A water quality survey has been performed on selected lakes and streams in southwest China. The purpose of the study was to measure the concentrations of acidic deposition and surface water chemistry in a region of severe air pollution, forest decline, and relatively sensitive geology to acidic deposition. It is shown that, although there are some high elevation lakes of low acid neutralizing capacity (ANC -1), acidification of lakes has not occurred in southwest China due to production of base cations in soil and dry deposition of dust that serves to neutralize acidic deposition. Water chemistry is buffered by high base cation concentrations (Ca2+, Mg2+, Na+, and K+) greater than 300 μeq L-1, and pH values are always greater than 6.5. 24 refs., 4 figs., 7 tabs

  16. Echinococcus granulosus Prevalence in Dogs in Southwest Nigeria

    Oyeduntan Adejoju Adediran

    2014-01-01

    Full Text Available Echinococcosis is a public health parasitic disease that is cosmopolitan (Echinococcus granulosus in its distribution. Domestic dogs (Canis familiaris have been recognised as the definitive host of the parasite. The present study was carried out to determine the prevalence of canine echinococcosis in Southwest Nigeria using direct enzyme linked immunosorbent assay (ELISA to detect sera antigen. Two hundred and seventy-three (273 canine sera were tested for the presence of Echinococcus antigen. Purpose of keeping (hunting or companion, age (young or adult, and sex of each dog were considered during sampling. Total prevalence recorded was 12.45% (34/273. There was significant difference (P0.05 between young and adult dogs. There was no association between sex and prevalence of canine echinococcosis. The result of this study established the presence of canine echinococcosis in Southwest Nigeria; thus there is the possibility of occurrence of zoonotic form of the disease (human cystic hydatid diseases in the region.

  17. Development of an estuarine assessment scheme for the management of a highly urbanised catchment/estuary system, Sydney estuary, Australia.

    Birch, G F; Gunns, T J; Chapman, D; Harrison, D

    2016-05-01

    As coastal populations increase, considerable pressures are exerted on estuarine environments. Recently, there has been a trend towards the development and use of estuarine assessment schemes as a decision support tool in the management of these environments. These schemes offer a method by which complex environmental data is converted into a readily understandable and communicable format for informed decision making and effective distribution of limited management resources. Reliability and effectiveness of these schemes are often limited due to a complex assessment framework, poor data management and use of ineffective environmental indicators. The current scheme aims to improve reliability in the reporting of estuarine condition by including a concise assessment framework, employing high-value indicators and, in a unique approach, employing fuzzy logic in indicator evaluation. Using Sydney estuary as a case study, each of the 15 sub-catchment/sub-estuary systems were assessed using the current scheme. Results identified that poor sediment quality was a significant issue in Blackwattle/Rozelle Bay, Iron Cove and Hen and Chicken Bay while poor water quality was of particular concern in Duck River, Homebush Bay and the Parramatta River. Overall results of the assessment scheme were used to prioritise the management of each sub-catchment/sub-estuary assessed with Blackwattle/Rozelle Bay, Homebush Bay, Iron Cove and Duck River considered to be in need of a high priority management response. A report card format, using letter grades, was employed to convey the results of the assessment in a readily understood manner to estuarine managers and members of the public. Letter grades also provide benchmarking and performance monitoring ability, allowing estuarine managers to set improvement targets and assesses the effectiveness of management strategies. The current assessment scheme provides an effective, integrated and consistent assessment of estuarine health and

  18. Residual fluxes of water and nutrient transport through the main inlet of a tropical estuary, Cochin estuary, West Coast, India.

    Vinita, J; Lallu, K R; Revichandran, C; Muraleedharan, K R; Jineesh, V K; Shivaprasad, A

    2015-11-01

    Determining robust values for estuarine material fluxes has been a complex task and an interdisciplinary research challenge. With the advent of acoustic Doppler profilers (ADPs) having bottom-track capability and which provides three-dimensional current velocity profiles, more accurate estimation of cross-sectional fluxes is far accomplished in unsteady and bidirectional flow conditions of estuaries. This paper reports for the first time the discharge measurements conducted across Cochin inlet using ADP to examine the spring-neap variability in residual fluxes of water and nutrients during dry season. Cross-sectional current velocity profiles and salinity profiles were captured using ADP and conductivity temperature depth (CTD) instrumentation. Samples of surface and bottom water were also collected at 3-h intervals. The results indicated that there is a distinct transition from the neap to spring tides related to flow and salinity structure. The neap tide was partially mixed with large diurnal inequalities whereas the spring tide was well-mixed with symmetric tides. During ebb, an increase in the concentrations of nitrate, nitrite, phosphate, and silicate was noticed indicating upstream sources for their inputs. In contrast, elevated levels of ammonia were found in the estuary throughout the period of observation. There was net residual outflow during both tides, and the computed residual water fluxes of neap doubled that of spring. The strong ebb currents and the increased nutrient concentrations during ebb resulted in the export of all nutrients (except ammonia during spring) into the sea. The findings of this study highlight the consequences of anthropogenic interventions in the estuary and their effects on the fluxes of ecologically relevant substances. PMID:26446129

  19. The chimpanzees of Oluwa Forest Reserve, southwest Nigeria

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

    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 reser...

  20. Marine mammal strandings in the New Caledonia region, Southwest Pacific

    Borsa, Philippe

    2006-01-01

    International audience Four hundred twenty three marine mammals, in 72 stranding events, were recorded between 1877 and 2005 in New Caledonia, the Loyalty Islands, and Vanuatu in the southwest Pacific. Sixteen species were represented in this count, including: minke whale, Balaenoptera acutorostrata (1 single stranding), sei whale, B. borealis (1 single stranding), blue whale, B. musculus (1 single stranding), humpback whale, Megaptera novaeangliae (2 single strandings), giant sperm whale,...

  1. Sea cucumber exploitation in the Toliara region of southwest Madagascar

    Rasolofonirina, R.; Conand, Chantal

    1998-01-01

    Sea cucumber harvesting is a traditional activity in Madagascar (Conand et al., 1997) and is very actively pursued in the south-west (Toliara). Several sources (e.g. Provincial Trade Department, Provincial Marine Fisheries Service) indicate that, between 1979 and 1986, exports fluctuated between 10 and 56 t. Data on recent exports show a very large increase, with volumes of more than 500 t. However, available data are insufficient to diagnose and analyse current over-exploitation, as the fish...

  2. Biological Studies on groundwater Crustaceans in Southwest Anatolia, Turkey

    Könemann, Stefan

    1997-01-01

    In 1987 a major biospeleogical expedition, ‘Speleo Nederland’, was carried out along the coastal Taurus mountains in southwest Anatolia (Turkey). ‘Speleo Nederland’ was focused on collecting the fauna of caves, wells, subterranean waterflows, and the interstices of marine gravel beaches. The special yield of stygobiont crustaceans, predominantly amphipods of the genus Bogidiella, promised to serve as an interesting case study to the colonization of inland groundwater by marine organisms. Now,...

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

    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.

  4. The Road to Maternal Death In Rural Southwest Ethiopia

    Deribe, Kebede; Biadgilign, Sibhatu; Amberbir, Alemayehu; Belachew, Tefera; Woldemichael, Kifle

    2010-01-01

    The study explored cultural beliefs and practices contributing to maternal deaths together with maternal deaths reviews as testimonial. Six maternal deaths were retrospectively observed in rural southwest Ethiopia. Four of the 6 deaths occurred due to direct obstetric causes. Substandard primary and referral care, not understanding the severity of the problem, and lack of transport were the major themes identified as contributing factors. The result highlighted the need to improving primary h...

  5. Retinal Detachment in Southwest Ethiopia: A Hospital Based Prospective Study

    Asaminew, Tsedeke; Gelaw, Yeshigeta; Bekele, Sisay; Solomon, Berhan

    2013-01-01

    Purpose The incidence of retinal detachment in Blacks is generally considered to be low though there are few supporting studies in Africa. This study, thus, aimed at describing the clinical profile of patients with retinal detachment in Southwest Ethiopia. Methods A hospital-based study was done on all consecutive retinal detachment patients who presented to Jimma University Hospital over six months period. A semi-structured questionnaire was used to collect patients’ sociodemographic charact...

  6. Many southwest hosptials will receive decreased CMS reimbursement

    Robbins RA

    2013-01-01

    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 ...

  7. The tectonic evolution of the Altavista area, Southwest Virginia Piedmont

    Gates, Alexander E

    1986-01-01

    The Altavista area lies at the north end of a large area of continuous detailed mapping in the proposed westward thrusted Smith River Allochthon of the Southwest Virginia Piedmont. It also lies at the south end of an area of continuous mapping in the central Virginia Piedmont. The stratigraphy of the Smith River Allochthon has not been related to any other in the Southern Appalachians. The units defined to the north of Altavista are Late Precambrian to Early Paleozoic in age an...

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

    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.

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

    Shchepetkina, Alina; Gingras, Murray K.; Pemberton, S. George

    2016-08-01

    Through the integration of sedimentological and ichnological observations, this paper explores the character of sediments deposited across the fluvio-tidal transition zone of the upper microtidal, mixed-energy, sand-dominated Ogeechee River estuary, Georgia, USA. A transect of tidally influenced to fluvial channel-bars and their facies variability is reported. Field and laboratory methods were employed, including observation of physical and biogenic sedimentary structures on the point-bar surfaces and in trenches, collection of grab samples, suction and box coring, grain size and total organic carbon analyses, optical microscopy, core logging, and daylight photography. The data presented in the paper can help in predicting facies changes across the fluvio-tidal transition of sand-dominated fluvio-tidal deposits in the rock record. The lower inner estuary is characterized by medium-fine and fine-medium sand with planar and trough cross-bedding, small-scale ripple lamination, tidal sedimentary structures (flaser and wavy bedding, herringbone cross-stratification), abundant organic debris, and mud rip-up clasts. Bioturbation of the intertidal point bars is low, but cryptobioturbation is locally observed. Upper inner estuary deposits comprise coarse-medium- and medium-coarse-grained sand, and are characterized by faint high-angle planar and trough cross-bedding. Organic debris, mud rip-up clasts, herringbone and current-ripple lamination are rarely observed. Bioturbation is absent to sparse. The fluvio-tidal transition is represented by very-coarse- to coarse-grained sand and granules. Physical sedimentary structures constitute massive, graded planar and trough cross-bedding with abundant plant detritus. Except for rare Siphonichnus- and Lockeia-like traces, bioturbation is absent. The fluvial setting is characterized by coarse-medium sand with unidirectional cross-bedding, current-ripple lamination, and rare organic-rich mud clasts. Bioturbation is absent. Inner

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

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

    1985-11-01

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

  11. Pennsylvanian foreland deformation of Wichita uplift, southwest Oklahoma

    McConnell, D.

    1986-05-01

    Pennsylvanian foreland deformation associated with the Ouachita orogene reactivated a west-northwest-east-southeast Cambrian basement trend, the southern Oklahoma aulacogen, to form the Wichita uplift, southwest Oklahoma. The 30-km-wide subsurface Frontal fault zone separates the uplift from the Anadarko basin to the north. Horizontal shortening across this fault zone is estimated at 7-15 km (20-40%), vertical displacement totals 9-10 km from the uplift to the basin. Folds are mapped on an interformational scale within the Frontal fault zone, and on an intraformational scale (Cambro-Ordovician Arbuckle Group) in the Slick Hills, southwest Oklahoma. Additional shortening occurred along southwest dipping mountain flank thrusts and on bedding plane thrusts, respectively. Hanging wall blocks of major faults contain the shallow dipping limb and anticlinal hinge zone of the interformational scale folds. Oil and gas production is generally restricted to these anticlinal crests within Paleozoic rocks. Deep wells (> 6000 m) that have penetrated footwall imbricates of the mountain flank thrusts have drilled through steep-overturned beds and tight recumbent folds before passing through faults into a normal stratigraphic sequence. Basement thrust loading of the southern margin of the Anadarko basin controlled the trend (west-northwest-east-southeast) of the axis of maximum deposition within the basin during the Pennsylvanian.

  12. Oxygen depletion off the Changjiang (Yangtze River)Estuary

    LI; Daoji; (李道季); ZHANG; Jing; (张经); HUANG; Daji; (黄大吉); WU; Ying; (吴莹); LIANG; Jun; (梁俊)

    2002-01-01

    In a survey on the Yellow Sea and the East China Sea on August 20-30 of 1999, we found a hypoxic zone (<2 mg/L) of 13700 km2 with an average thickness of 20m at the bottom of the Changjiang (Yangtze River) Estuary, with an oxygen minimum value of 1 mg/L. The extension of the dissolved oxygen deficiency extended to the 100m isobath in a southeastward direction along the bottom of the continental shelf of the East China Sea. During the last two decades, the minimum dissolved oxygen values in the low oxygen region of the Changjiang Estuary have decreased from 2.85 mg/L to 1 mg/L. In the hypoxic zone, the apparent oxygen utilization (AOU) was 5.8 mg/L and the total oxygen depletion approximately 1.59×106 t. The strong halocline above the hypoxic zone, as a result of affluent water from the Changjiang, Taiwan Warm Current (TWC), and the high concentrations of particle organic carbon (POC) and nitrogen (PON) are the major factors causing the formation of the hypoxic zone. The POC: PON ratios and nutrient concentration distributions in the hypoxic zone suggest that the oxygen deficiency in the bottom water during the summer in the East China Sea off the Changjiang is the result of organic carbon production enhanced by nutrients from the Changjiang and fluvial organic matter input, followed by a shift in regeneration of nutrients in the East China Sea.

  13. Modeling Residual Circulation and Stratification in Oujiang River Estuary

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

    2012-01-01

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

  14. The occurrence of selected human pharmaceutical compounds in UK estuaries.

    Thomas, Kevin V; Hilton, Martin J

    2004-09-01

    This report describes a scoping study conducted in order to establish whether pharmaceutical compounds may be present in UK estuaries. Surface water samples collected from five UK estuaries were analysed for the presence of 14 pharmaceutical compounds selected from the priority lists of the UK Environment Agency and the Oslo and Paris Commission (OSPAR). The pharmaceutical compounds/metabolites clofibric acid, clotrimazole, dextropropoxyphene, diclofenac, ibuprofen, mefenamic acid, propranolol, tamoxifen and trimethoprim were detected at measurable concentrations in the samples collected. The concentrations of erythromycin, lofepramine, paracetamol, sulfamethoxazole and acetyl-sulfamethoxazole were all below the limits of detection of the methods used (between 4 and 20 ng l(-1)). The anti-fungal agent clotrimazole was the most frequently detected at a maximal concentration of 22 ng l(-1) and a median concentration of 7 ng l(-1). The analgesic compound ibuprofen was detected at a maximal concentration of approximately 930 ng l(-1) and a median concentration of 48 ng l(-1), whilst the other pharmaceutical compounds were detected between the limits of detection of the method used and 570 ng l(-1). PMID:15325211

  15. Mathematical simulation of sediment and radionuclide transport in estuaries

    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 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

  16. Evaluation on Comprehensive Benefit of Natural Forest Protection Project in Southwest China

    2011-01-01

    According to the problem of seriously degraded natural forest in Southwest China prior to the implementation of Natural Forest Protection Project, under the guidance of principle of practicality and systematicness, we establish the comprehensive-benefit evaluation index system of restoring the degraded natural forest in Southwest China, including 3 second-level indices, 12 third-level indices and 24 fourth-level indices. In addition, we use the method of Analytic Hierarchy Process to conduct comprehensive-benefit evaluation on implementation of Natural Forest Protection Project in Southwest China. The results show that since ten years of implementation of Natural Forest Protection Project in Southwest China, it has gained considerable comprehensive benefit. The comprehensive evaluation index of Natural Forest Protection Project in Southwest China is 83.08; the ecological benefit index of Natural Forest Protection Project in Southwest China is 56.75; the economic benefit index of Natural Forest Protection Project in Southwest China is 19.05; the social benefit index of Natural Forest Protection Project in Southwest China is 7.28. The effect of construction of Natural Forest Protection Project in Southwest China is good. The evaluation index system and research results in this paper will provide the empirical guidance for comprehensive-benefit evaluation of Natural Forest Protection Project in China, and especially in Southwest China.

  17. Trophic interactions of Platichthys flesus and Solea solea juveniles in the Lima estuary nursery (NW Portugal

    Cláudia Mendes

    2015-12-01

    Full Text Available Trophic interactions play a key role in nursery habitats, and by affecting growth and condition of the juveniles, may control the quality of a given estuarine nursery. This study investigated the trophic ecology of flounder (Platichthys flesus and common sole (Solea solea juveniles in the Lima estuary nursery. Feeding location, main organic matter sources, and prey of the target species were assessed by carbon (δ13C and nitrogen (δ15N stable isotopes, as well as by stomach content analysis. The juveniles, macroinvertebrates, and sediment and water column samples were collected in August 2014 in the lower, middle and upper sections of the Lima estuary. The diet of 0+ flounder relied upon prey from the upper estuary (salinity >5, namely Chironomid larvae and Corophium spp. which showed the role of the upper estuary prey to the 0+ flounder diet and suggest the relative site fidelity of the young juveniles. In contrast, 1+ flounder juveniles had a diverse diet based on bivalves, polychaetes and crustaceans, and a variable stable isotope signature indicating they fed in different areas along the estuary. The 1+ sole juveniles also fed on polychaetes, crustaceans, and bivalves, but the stable isotope values suggested a dependence on the lower estuary (salinity >30 and marine food web sources. Such differential use of food may be understood as a strategic approach to reduce intra- and interspecific competition and thus ensuring the use of Lima estuary as nursery area for these two flatfish species.

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

    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.

  19. A numerical study of local variations in tidal regime of Tagus estuary, Portugal.

    João Miguel Dias

    Full Text Available Tidal dynamics of shallow estuaries and lagoons is a complex matter that has attracted the attention of a large number of researchers over the last few decades. The main purpose of the present work is to study the intricate tidal dynamics of the Tagus estuary, which states as the largest estuary of the Iberian Peninsula and one of the most important wetlands in Portugal and Europe. Tagus has large areas of low depth and a remarkable geomorphology, both determining the complex propagation of tidal waves along the estuary of unknown manner. A non-linear two-dimensional vertically integrated hydrodynamic model was considered to be adequate to simulate its hydrodynamics and an application developed from the SIMSYS2D model was applied to study the tidal propagation along the estuary. The implementation and calibration of this model revealed its accuracy to predict tidal properties along the entire system. Several model runs enabled the analysis of the local variations in tidal dynamics, through the interpretation of amplitude and phase patterns of the main tidal constituents, tidal asymmetry, tidal ellipses, form factor and tidal dissipation. Results show that Tagus estuary tidal dynamics is extremely dependent on an estuarine resonance mode for the semi-diurnal constituents that induce important tidal characteristics. Besides, the estuarine coastline features and topography determines the changes in tidal propagation along the estuary, which therefore result essentially from a balance between convergence/divergence and friction and advection effects, besides the resonance effects.

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

    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.

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

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

  2. Accumulation of Phosphorus and Heavy Metals in the Swan-Canning Estuary, Western Australia

    Gerritse, R. G.; Wallbrink, P. J.; Murray, A. S.

    1998-08-01

    Accumulation rates of P and of Zn, Cd, Pb and Cu were measured in sediment cores from the Swan-Canning Estuary in Western Australia. The main sources of P in sediments are catchments of the major tributaries Ellen Brook and Avon River. Since 1940, anthropogenic P has increased about five times in sediments of Ellen Brook and has almost trebled in sediments of the estuary. Records show that since 1940 dissolved inorganic P in the estuary has increased between two and three times. Though dissolved inorganic P appears to be conservatively mixed in the estuary, sediment inventories suggest that a significant part of the input of P is retained in the estuary. A combination of high concentrations of dissolved P in Ellen Brook and large fluxes of particulate matter from the Avon River could explain this. Concentrations of Zn, Cd, Pb and Cu in sediments have risen significantly since colonial settlement and, unlike P concentrations, have been dominated by inputs from sources near the estuary. Vertical distributions of metals in sediment cores from the estuary suggest that, historically, concentrations of Zn and Cd started increasing first, followed by Cu and then P and Pb.Acid extractable Pb, unlike Zn, Cd and Cu, in surface sediments is greater than expected from equilibration with the water column. This is attributed to the presence of particulate Pb-oxides from road runoff.

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

    LIU Dazhao; FU Dongyang; XU Bing; SHEN Chunyan

    2012-01-01

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

  4. Carbon budgets for two Portuguese estuaries: implications for the management and conservation of coastal waters

    Ana P. Oliveira

    2014-07-01

    The results presented illustrate that Tagus and Sado estuaries represent an important land/ocean boundary for carbon transformation and emission, and confirm the anthropogenic pressure that these estuaries are subject to. Carbon budgets vary markedly within and between these two estuaries reflecting the human pressure. Anthropogenic inputs, autochthonous carbon production and primary production are indicated as the main responsible for the carbon production within the estuaries. Both estuaries export carbon to the ocean and to the atmosphere. The inorganic carbon faction has a major role in the carbon budget, enriching the ocean in carbon dioxide, contributing this for the greenhouse effect. Our understanding of organic and inorganic carbon fluxes in Tagus and Sado estuaries is vital for an efficient protection and preservation of such ecosystems being helpful in limit human-caused damage and in restoring damaged estuarine/coastal ecosystems. In addition, the economic impact of the carbon fluxes to the atmosphere, estimated as €375,000 per year, creates the appropriate incentives to reduce emissions and shift them to higher-value uses. Suggesting, therefore, a coastal management re-oriented towards a more adaptive approach through the use of carbon market-based policies. This study is a contribution to the integration of coastal and global carbon cycles. However, additional efforts are required to fully merge other components subsystems, such as salt marshes, with these budgets. Moreover, a fully comprehension of the community metabolism in these estuaries will greatly improve this integration.

  5. Assessment of heavy metals bioavailability and toxicity toward Vibrio fischeri in sediment of the Huelva estuary.

    Rosado, Daniel; Usero, José; Morillo, José

    2016-06-01

    Relationship between toxicity and bioavailable metals in sediments from the Huelva estuary and its littoral of influence was analyzed. Toxicity was assessed with Microtox(®) bioassay using a marine luminescent bacterium: Vibrio fischeri. Bioavailable metals were considered as both, acid extractable fraction of BCR procedure and the sum of exchangeable and bound to carbonates fractions of Tessier sequential extraction. A bioavailable metals index was calculated to integrate results in a single figure. Toxicity and bioavailable metals showed a similar pattern. Higher levels were found in the estuary than in the littoral (140 TU/g). In Huelva estuary, highest levels were found in the Tinto estuary (5725 TU/g), followed by the Odiel estuary (5100 TU/g) and the Padre Santo Canal (2500 TU/g). Results in this area were well over than those in nearby estuaries. Furthermore, they are similar to or even higher than those in other polluted sediments around the world. Bioavailable metal index showed a stronger correlation with acid extractable fraction of BCR (R(2) = 0.704) than that for the sum of exchangeable and bound to carbonates fractions of Tessier (R(2) = 0.661). These results suggest that bioavailable metals are an important source of sediment toxicity in the Huelva estuary and its littoral of influence, an area with one of the highest mortality risks of Spain. PMID:27002282

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

    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.

  7. [Water and environment in the Southwest of Madagascar].

    Razanamparany, L

    1993-04-01

    The dry and arid southwest region of Madagascar is not a desert but resembles the Sahel region of West Africa. The chronic water deficit is aggravated by the heat and constant winds that accelerate evapotranspiration on the permeable soils. The dryness occurs because the southwest region lies outside the main pluviogenic systems. Erosion occurs at all seasons. In the winter the sun and winds are the main causes, while the rare storms are more conducive to run-off and to erosion than to absorption. The acute water shortage in the southwest has prompted hydrogeologic research and well-drilling, but the high salt content of the water and other impurities will be a limiting factor for development of the area. The population of the southwest is extremely mobile. Human settlements are concentrated in the valleys and depressions and along major roads. Customary rights to land under the control of the traditional chiefs regulate tenure in most areas. But especially in the river bottoms, the coming of cash crops cultivated with modern equipment has resulted in significant erosion which has aggravated ecological problems. Accelerating soil degradation has led peasants to extend their lands under cultivation to the detriment of forest cover. Cattle herding remains the principal economic activity in the southwest. Herding has progressed from nomadism to pastoralism, but it remains a sign of power and wealth. Transhumance is the strategy of herders faced with shortages of water and pasturage, demographic pressure, and environmental degradation. Raising of sheep and goats constitutes a supplemental food source, medium of exchange, and form of savings. But angora goats graze on everything in their path, devastating their surrounds. Fear of cattle thefts militates against efforts to improve the quality of the stock. The various problems together have prompted a wasteful exploitation of the forest resources. Development strategies for the area explored by the government have all

  8. Evaluation of abiotic stresses of temperate estuaries by using resident zooplankton: A community vs. population approach

    Paul, Sourav; Wooldridge, Tris; Perissinotto, Renzo

    2016-03-01

    By using permanently resident zooplankton, we assessed the ecological level (i.e. community and or population) that provides more in-depth indication of the stress related to salinity and temperature fluctuations in temperate estuaries. In the semi-arid warm temperate South Africa, the Gamtoos estuary experiences a full salinity gradient maintained by irregular but relatively frequent freshwater pulses, whereas the Kromme estuary is euhaline throughout its extent and receives only occasional freshwater inputs when the storage reservoir six km upstream overtops. Changes in the species evenness index of Pielou and the abundances of estuarine resident zooplankton species were modelled against salinity and temperature variations of respective estuaries. In the Gamtoos estuary, response of individual populations provided more in-depth information regarding zooplankton variability. However the most abundant resident zooplankton i.e. Acartia longipatella a copepod was not the best predictor of the salinity and temperature fluctuations. Conversely, the Kromme estuary study provided insights into the potential vulnerability of the resident estuarine zooplankton community to cold. Further, the population level study exposed responses of specific species against salinity changes. We discuss the pros and cons of designing ecological indicators of abiotic stress based on specific species, targeted to specific ecological level, and needs of considering the frequency and magnitude of fresh water inflow in an estuary. A suggestion is to use specific taxonomic group(s) (e.g. Copepods) to better understand the abiotic stress factors of specific set of estuaries (e.g. freshwater rich/starved) until a 'one size fits all' indicator is found for temperate estuaries.

  9. Food web analysis in two permanently open temperate estuaries: consequences of saltmarsh loss?

    Svensson, Carl J; Hyndes, Glenn A; Lavery, Paul S

    2007-09-01

    Saltmarsh vegetation, seston and microphytobenthos are all conspicuous components of most temperate estuaries and they potentially contribute to the estuarine food chain. Yet their relative contributions are unclear, as is the significance of saltmarsh losses through natural and human-induced impacts. This study aimed to quantitatively determine the contribution of various types of primary producers to detritus in the Walpole-Nornalup Estuary and Leschenault Inlet, two permanently open estuaries in SW Australia, and, estimate the flow of different types of detritus to higher trophic levels, using carbon ((13)C) and nitrogen ((15)N) stable isotopes as tracers. Results of the mixing model indicated that seston, microphytobenthos and to some extent seagrass and fringing saltmarsh were the main contributors to the detrital pool in both estuaries. However, the relative contribution of different primary producers varied both within and between estuaries. The contribution of saltmarsh was higher at sites close to rivers and dense fringing vegetation, while seston, microphytobenthos and seagrass dominated the detrital material at other sites. Benthic harpacticoid copepods were shown to feed on detritus though they appeared to actively select for different components of the detritus depending on site and estuary. Isotopic signatures of other consumers indicated that fish and invertebrates derived nutrients from MPB and detritus, either directly as food or indirectly through feeding on invertebrates. The overall contribution of saltmarsh to detritus was lower in Leschenault Inlet than in Walpole-Nornalup Estuary, possibly as a result of increased clearing of fringing vegetation around Leschenault Inlet. This pattern was however not reflected in harpacticoid food. Therefore, although losses of fringing saltmarsh around estuaries have the potential to significantly affect estuarine food webs, the significance of such losses will be site- and estuary-dependent. PMID:17382379

  10. Linking biogeochemistry to hydro-geometrical variability in tidal estuaries: a generic modeling approach

    Volta, Chiara; Gildas Laruelle, Goulven; Arndt, Sandra; Regnier, Pierre

    2016-03-01

    This study applies the Carbon-Generic Estuary Model (C-GEM) modeling platform to simulate the estuarine biogeochemical dynamics - in particular the air-water CO2 exchange - in three idealized tidal estuaries characterized by increasing riverine influence, from a so-called "marine estuary" to a "riverine estuary". An intermediate case called "mixed estuary" is also considered. C-GEM uses a generic biogeochemical reaction network and a unique set of model parameters extracted from a comprehensive literature survey to perform steady-state simulations representing average conditions for temperate estuaries worldwide. Climate and boundary conditions are extracted from published global databases (e.g., World Ocean Atlas, GLORICH) and catchment model outputs (GlobalNEWS2). The whole-system biogeochemical indicators net ecosystem metabolism (NEM), C and N filtering capacities (FCTC and FCTN, respectively) and CO2 gas exchanges (FCO2) are calculated across the three idealized systems and are related to their main hydrodynamic and transport characteristics. A sensitivity analysis, which propagates the parameter uncertainties, is also carried out, followed by projections of changes in the biogeochemical indicators for the year 2050. Results show that the average C filtering capacities for baseline conditions are 40, 30 and 22 % for the marine, mixed and riverine estuary, respectively, while N filtering capacities, calculated in a similar fashion, range from 22 % for the marine estuary to 18 and 15 % for the mixed and the riverine estuaries. Sensitivity analysis performed by varying the rate constants for aerobic degradation, denitrification and nitrification over the range of values reported in the literature significantly widens these ranges for both C and N. Simulations for the year 2050 suggest that all estuaries will remain largely heterotrophic, although a slight improvement of the estuarine trophic status is predicted. In addition, our results suggest that, while the

  11. Carbon budgets for two Portuguese estuaries: implications for the management and conservation of coastal waters

    Oliveira, Ana P

    2014-01-01

    Abstract: Carbon budgets vary markedly within and between Tagus and Sado estuaries reflecting the human pressure. These estuaries seem to generate carbon within a total of 0.13 MtC yr-1 for Tagus and 0.02 MtC yr-1 for Sado. Anthropogenic inputs, autochthonous carbon production and primary production are indicated as the main responsible for the carbon production within the estuaries. Carbon exported to the ocean and to the atmosphere by both estuarine systems is higher during the non-producti...

  12. Greenhouse gas (N2O) emission from Portuguese estuaries

    Célia Gonçalves

    2014-01-01

    Abstract: The contribution of nitrous oxide (N2O) emissions to the estuarine nitrogen (N) balance are investigated for Tagus (May 2006), Minho and Lima estuaries (September 2006). N load to Tagus (3.48 Mg N yr-1) and Minho (3.25 Mg N yr-1) are similar in both estuaries but higher then Lima (0.34 Mg N yr-1), being well related to freshwater inflow. Estuaries act as sink of N. In Tagus and Minho most of the N is removed within the system (67% to 70%), while in Lima this value falls to 38.6 %. A...

  13. Modelling nitrogen and phosphorus cycles and dissolved oxygen in the Zhujiang Estuary Ⅱ. Model results

    Guan Weibing; Wong Lai-Ah; Xu Dongfeng

    2001-01-01

    In the present study, the ecosystem-based water quality model was applied to the Pearl River (Zhujiang) Estuary. The model results successfully represent the distribution trend of nutrients and dissolved oxygen both in the horizontal and vertical planes during the flood season, and it shows that the model has taken into consideration the key part of the dynamical, chemical and biological processes existing in the Zhujiang Estuary. The further studies illustrate that nitrogen is in plenty while phosphorus and light limit the phytoplankton biomass in the Zhujiang Estuary during the flood season.

  14. Modeling 226Ra behaviour in a Spanish estuary affected by the phosphate industry

    The behaviour of 226Ra in a system like this estuary is complex since radionuclides are affected by tidal actions and interactions with sediments through adsorption/desorption reactions and erosion/deposition processes. A numerical 2D depth-averaged model of the estuary has been developed, including processes mentioned above. It has been applied to reproduce experimental data measured after a release from the industrial complex in the Odiel River and after an accidental release in the Tinto River from the gypsum piles. The model has also been applied to simulate the self-cleaning process observed in the estuary after the direct releases from the fertilizer complex were stopped

  15. A Numerical Study of Local Variations in Tidal Regime of Tagus Estuary, Portugal

    Dias, João Miguel; Valentim, Juliana Marques; Sousa, Magda Catarina

    2013-01-01

    Tidal dynamics of shallow estuaries and lagoons is a complex matter that has attracted the attention of a large number of researchers over the last few decades. The main purpose of the present work is to study the intricate tidal dynamics of the Tagus estuary, which states as the largest estuary of the Iberian Peninsula and one of the most important wetlands in Portugal and Europe. Tagus has large areas of low depth and a remarkable geomorphology, both determining the complex propagation of t...

  16. Food web dynamics in a temperate temporarily open/closed estuary (South Africa)

    Froneman, P. W.

    2004-01-01

    Size fractionated chlorophyll- a (chl- a), primary production and zooplankton (mesozooplankton (200-2000 μm) and microheterotrophs (freshwater inflow into the estuary. The inflow of freshwater into the estuary also coincided with a shift in the size structure of the phytoplankton community with large cells (>5 μm) dominating total chl- a and production. During periods of reduced freshwater inflow into the estuary, total chl- a and production were dominated by small (preferred food particle size between the microheterotrophs and mesozooplankton.

  17. Trace metal partitioning over a tidal cycle in an estuary affected by acid mine drainage (Tinto estuary, SW Spain)

    Hierro, A. [Department of Physics, Universitat Autònoma de Barcelona, 08193 Bellaterra (Spain); Department of Applied Physics, Facultad de Ciencias Experimentales, University of Huelva, Campus de El Carmen, Campus de Excelencia Internacional del Mar CEIMAR, 21071 Huelva (Spain); Olías, M., E-mail: manuel.olias@dgyp.uhu.es [Department of Geodynamics and Paleontology, Facultad de Ciencias Experimentales, University of Huelva, Campus de El Carmen, Campus de Excelencia Internacional del Mar CEIMAR, 21071 Huelva (Spain); Cánovas, C.R. [Department of Geodynamics and Paleontology, Facultad de Ciencias Experimentales, University of Huelva, Campus de El Carmen, Campus de Excelencia Internacional del Mar CEIMAR, 21071 Huelva (Spain); Martín, J.E.; Bolivar, J.P. [Department of Applied Physics, Facultad de Ciencias Experimentales, University of Huelva, Campus de El Carmen, Campus de Excelencia Internacional del Mar CEIMAR, 21071 Huelva (Spain)

    2014-11-01

    The Tinto River estuary is highly polluted with the acid lixiviates from old sulphide mines. In this work the behaviour of dissolved and particulate trace metals under strong chemical gradients during a tidal cycle is studied. The pH values range from 4.4 with low tide to 6.9 with high tide. Precipitation of Fe and Al is intense during rising tides and As and Pb are almost exclusively found in the particulate matter (PM). Sorption processes are very important in controlling the mobility (and hence bioavailability) of some metals and particularly affect Cu below pH 6. Above pH ∼ 6 Cu is desorbed, probably by the formation of Cu(I)–chloride complexes. Although less pronounced than Cu, also Zn desorption above pH 6.5 seems to occur. Mn and Co are affected by sorption processes at pH higher than ca. 6. Cd behaves conservatively and Ni is slightly affected by sorption processes. - Highlights: • The Tinto estuary shows strong pH gradients and high trace elements concentrations. • PM has a hysteretic relationship with tides and high contents of Fe, Al, As and Pb. • Co and Mn are controlled by river and sea water mixing and sorption processes. • Sorption processes strongly affect Cu below pH 6, above this value Cu is desorpted. • Cadmium behaves conservatively along the pH range studied (4.4–6.9)

  18. Trace metal partitioning over a tidal cycle in an estuary affected by acid mine drainage (Tinto estuary, SW Spain)

    The Tinto River estuary is highly polluted with the acid lixiviates from old sulphide mines. In this work the behaviour of dissolved and particulate trace metals under strong chemical gradients during a tidal cycle is studied. The pH values range from 4.4 with low tide to 6.9 with high tide. Precipitation of Fe and Al is intense during rising tides and As and Pb are almost exclusively found in the particulate matter (PM). Sorption processes are very important in controlling the mobility (and hence bioavailability) of some metals and particularly affect Cu below pH 6. Above pH ∼ 6 Cu is desorbed, probably by the formation of Cu(I)–chloride complexes. Although less pronounced than Cu, also Zn desorption above pH 6.5 seems to occur. Mn and Co are affected by sorption processes at pH higher than ca. 6. Cd behaves conservatively and Ni is slightly affected by sorption processes. - Highlights: • The Tinto estuary shows strong pH gradients and high trace elements concentrations. • PM has a hysteretic relationship with tides and high contents of Fe, Al, As and Pb. • Co and Mn are controlled by river and sea water mixing and sorption processes. • Sorption processes strongly affect Cu below pH 6, above this value Cu is desorpted. • Cadmium behaves conservatively along the pH range studied (4.4–6.9)

  19. Improvement of Statistical Typhoon Rainfall Forecasting with ANN-Based Southwest Monsoon Enhancement

    Tsung-Yi Pan; Yi-Ting Yang; Hung-Chi Kuo; Yih-Chi Tan; Jihn-Sung Lai; Tsang-Jung Chang; Cheng-Shang Lee; and Kathryn Hua Hsu

    2011-01-01

    Typhoon Morakot 2009, with significant southwest monsoon flow, produced a record-breaking rainfall of 2361 mm in 48 hours. This study hopes to improve a statistical typhoon rainfall forecasting method used over the mountain region of Taiwan via an artificial neural network based southwest monsoon enhancement (ANNSME) model. Rainfall data collected at two mountain weather stations, ALiShan and YuShan, are analyzed to establish the relation to the southwest monsoon moisture flux which is calcul...

  20. Distribution, provenance and early diagenesis of major and trace metals in sediment cores from the Mandovi estuary, western India

    Prajith, A.; Rao, V. Purnachandra; Chakraborty, P.

    2016-03-01

    Major elements and trace metals were analyzed in four sediment cores recovered along a transect in the Mandovi estuary for their distribution, provenance and early diagenesis. The sediments were clayey silts in cores from the upper/lower estuary and sand-dominated in cores from the middle estuary/bay. Organic carbon (OC) content varied from 0.5 to 4%, with higher values in fine-grained sediments. The mean Fe and Mn contents of sediments from the upper/middle estuary were 3-5 times and 8-13 times, respectively higher than the reference sediment (RS) from the same estuary. The mean Fe and Mn contents of sediments from the lower estuary/bay were close to the RS. Strong inter-metal correlation among Ti, V, Cr and Zr in all the cores indicated their contribution from a common source, probably the laterites from hinterland. Trace metals were more enriched in fine-grained sediments than in sand-dominated sediments. Early diagenetic control on the redistribution of metal is evident in core sediments from the middle estuary to Bay. The distribution of Mo, U and Pb followed that of Fe and Mn in the upper estuary and OC in the lower estuary/bay. Our results indicated strong anthropogenic contribution of metals from ore deposits in the upper/middle estuary. The Mn and Cr contents of sediment in the upper/middle estuary and Fe in the middle estuary were highly enriched suggestive of 'significant pollution signal'. More trace metals from the middle estuary were moderately enriched. Speciation studies showed Mn and Pb occurred abundantly in non-residual phases. High Mn content and its high percentage in exchangeable and reductive phases indicate that it was susceptible to be mobilized. However, Fe, Cu and Ni occurred abundantly in residual phases and less percentage of them were expected to be bio-available.

  1. 2003 Southwest Florida Water Management District (SWFWMD) LiDAR: Marion County

    National Oceanic and Atmospheric Administration, Department of Commerce — Merrick and Company produced one foot contours, spot elevations, and obscured areas for the Southwest Florida Water Management District.

  2. Tides in the Mandovi and Zuari estuaries, Goa, west coast of India

    D Sundar; S R Shetye

    2005-10-01

    Mandovi and Zuari are two estuaries located in Goa,west coast of India.Variation of water level in the estuaries was monitored for a month at 13 locations using tide-poles during March –April 2003.Analysis of this data has provided for the first time,characteristics of how tidal constituents vary in the narrow and shallow estuaries,typical of those found along the west coast of India.At a distance of 45 km from the mouth the tidal range increased in both estuaries by approximately 20%.The tidal range at the upstream end of the two channels at the stations dropped sharply because of the increase in elevation of the channels.

  3. Study of age and growth of Indian sand whiting, sillago sihama (Forsskal) from Zuari estuary, Goa

    Shamsan, E.F.; Ansari, Z.A

    Present study consists age and growth of Sillago sihama. Total 1465 fish were collected from Zuari estuary during January 2004-April 2005 as a part of the above study. To evaluate the age at corresponding length, length frequency distribution (LFD...

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

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

    2008) at a fixed location (Yanam) in the Godavari estuary, India. River discharge was at its peak during July to September with a sharp decrease in the middle of December and complete cessation thereafter. Significant amount of dissolved inorganic...

  5. Sediment Data from Great Bay Estuary, New Hampshire (ARMSTRONG74 shapefile)

    U.S. Geological Survey, Department of the Interior — The sediment data presented in this data layer were from a geochemical study sited in Great Bay Estuary, New Hampshire. The analog data were originally converted...

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

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

  7. Diel-Cycling Hypoxia in Northern Gulf of Mexico Estuaries: Impacts and Protection of Aquatic Life

    Eutrophication of coastal ecosystems is a longstanding environmental concern, exacerbated by population growth and associated nutrient pollution, and ultimately resulting in increased incidence of hypoxia. Shallow and highly productive estuaries and embayments are particularly su...

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

    CHEN Xiaohong; CHEN Yongqin; LAI Guoyou

    2005-01-01

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

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

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

    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...

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

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

    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...

  11. 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...

  12. Drought-induced variability in dissolved organic matter composition in a marsh-dominated estuary

    Medeiros, Patricia M.; Seidel, Michael; Dittmar, Thorsten; Whitman, William B.; Moran, Mary Ann

    2015-08-01

    The composition of dissolved organic matter (DOM) in an estuary characterized by extensive salt marsh vegetation was investigated at the molecular level using ultrahigh-resolution mass spectrometry and stable carbon isotope analyses. Samples from multiple seasons covered different hydrological regimes, including anomalously low-discharge conditions. The untargeted approach used allowed for identifying the DOM molecular signatures associated with different DOM sources in the estuary. DOM composition was strongly modulated by river discharge at monthly scales, with high river flow leading to significant increases in the terrigenous signature of the DOM throughout the estuary. During a severe/exceptional drought, estuarine DOM was imprinted with a distinct signature of marsh-derived compounds. The frequency of occurrence of anomalously low-discharge conditions seems to have increased over the last decades. If predictions of anthropogenically driven changes in hydroclimate are confirmed, they will likely be accompanied by changes in DOM composition in estuaries at multidecadal time scales.

  13. 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...

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

    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

  15. Drivers of Variability of Diel-Cycling and Episodic Hypoxia In Northern Gulf of Mexico Estuaries

    Eutrophication of coastal ecosystems is a longstanding environmental concern, exacerbated by population growth and associated nutrient pollution, and ultimately resulting in increased incidence of hypoxia. Shallow and highly productive estuaries and embayments are particularly su...

  16. Temporal and Spatial Dynamics of Diel-Cycling Hypoxia in Four Northern Gulf of Mexico Estuaries

    Eutrophication of coastal ecosystems has accelerated in recent decades due to population growth and associated nutrient pollution, resulting in increased incidence of hypoxia. Shallow and highly productive estuaries and embayments are particularly susceptible to diel-cycling hypo...

  17. 2009 Puget Sound LiDAR Consortium (PSLC) Topographic LiDAR: Snohomish River Estuary

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

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

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

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

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

    George, M.D.

    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...

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

    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...

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

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

  2. Seasonal variability in penaeid prawn larval abundance in the Mandovi and Zuari estuaries, Goa

    Goswami, S.C.; Goswami, U.

    Seasonal variations in the occurrence and abundance of penaeid prawn larvae in the Mandovi and Zuari estuaries of Goa, India were studied. Larvae and postlarvae of commercially important species viz. Metapenaeus dobsoni (Miers), M. affinis (H. Milne...

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

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

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

  4. Predicting submerged aquatic vegetation cover and occurrence in a Lake Superior estuary

    Submerged aquatic vegetation (SAV) provides the biophysical basis for multiple ecosystem services in Great Lakes estuaries. Understanding sources of variation in SAV is necessary for sustainable management of SAV habitat. From data collected in 2011 using hydroacoustic survey met...

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

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

    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...

  6. 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 1981-2012. The...

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

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

    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...

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

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

    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...

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

    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.

  10. Southwest Indian Ocean Bathymetric Compilation (swIOBC)

    Jensen, L.; Dorschel, B.; Arndt, J. E.; Jokat, W.

    2014-12-01

    As result of long-term scientific activities in the southwest Indian Ocean, an extensive amount of swath bathymetric data has accumulated in the AWI database. Using this data as a backbone, supplemented by additional bathymetric data sets and predicted bathymetry, we generate a comprehensive regional bathymetric data compilation for the southwest Indian Ocean. A high resolution bathymetric chart of this region will support geological and climate research: Identification of current-induced seabed structures will help modelling oceanic currents and, thus, provide proxy information about the paleo-climate. Analysis of the sediment distribution will contribute to reconstruct the erosional history of Eastern Africa. The aim of swIOBC is to produce a homogeneous and seamless bathymetric grid with an associated meta-database and a corresponding map for the area from 5° to 39° S and 20° to 44° E. Recently, multibeam data with a track length of approximately 86,000 km are held in-house. In combination with external echosounding data this allows for the generation of a regional grid, significantly improving the existing, mostly satellite altimetry derived, bathymetric models. The collected data sets are heterogeneous in terms of age, acquisition system, background data, resolution, accuracy, and documentation. As a consequence, the production of a bathymetric grid requires special techniques and algorithms, which were already developed for the IBCAO (Jakobsson et al., 2012) and further refined for the IBCSO (Arndt et al., 2013). The new regional southwest Indian Ocean chart will be created based on these methods. Arndt, J.E., et al., 2013. The International Bathymetric Chart of the Southern Ocean (IBCSO) Version 1.0—A new bathymetric compilation covering circum-Antarctic waters. GRL 40, 1-7, doi: 10.1002/grl.50413, 2013. Jakobsson, M., et al., 2012. The International Bathymetric Chart of the Arctic Ocean (IBCAO) Version 3.0. GRL 39, L12609, doi: 10.1029/2012GL052219.

  11. Volcanoes magnify Metro Manila's southwest monsoon rains and lethal floods

    Lagmay, Alfredo Mahar; Bagtasa, Gerry; Crisologo, Irene; Racoma, Bernard Alan; David, Carlos Primo

    Many volcanoes worldwide are located near populated cities that experience monsoon seasons, characterised by shifting winds each year. Because of the severity of flood impact to large populations, it is worthy of investigation in the Philippines and elsewhere to better understand the phenomenon for possible hazard mitigating solutions, if any. During the monsoon season, the change in flow direction of winds brings moist warm air to cross the mountains and volcanoes in western Philippines and cause lift into the atmosphere, which normally leads to heavy rains and floods. Heavy southwest monsoon rains from 18-21 August 2013 flooded Metro Manila (population of 12 million) and its suburbs paralyzing the nation’s capital for an entire week. Called the 2013 Habagat event, it was a repeat of the 2012 Habagat or extreme southwest monsoon weather from 6-9 August, which delivered record rains in the mega city. In both the 2012 and 2013 Habagat events, cyclones, the usual suspects for the delivery of heavy rains, were passing northeast of the Philippine archipelago, respectively, and enhanced the southwest monsoon. Analysis of Doppler data, rainfall measurements, and Weather Research and Forecasting (WRF) model simulations show that two large stratovolcanoes, Natib and Mariveles, across from Manila Bay and approximately 70 km west of Metro Manila, played a substantial role in delivering extreme rains and consequent floods to Metro Manila. The study highlights how volcanoes, with their shape and height create an orographic effect and dispersive tail of rain clouds which constitutes a significant flood hazard to large communities like Metro Manila.

  12. Relevance of different spectral techniques to describe estuarine suspended sediment dynamics based on a high-frequency, long-term turbidity dataset

    Jalón Rojas, Isabel; Schmidt, Sabine; Sottolichio, Aldo

    2015-04-01

    Sediment dynamics in estuaries are complex and strongly variable over time scales ranging from seconds to years. Various forcings (turbulence, tides, river inflow, wind waves, morphological and climatic changes) may cause the temporal and spatial variability of suspended sediment (SS) concentrations. The evaluation of these SS dynamics by in-situ measurements have traditionally faced three difficulties: (1) the quantification of low-frequency variability that requires continuous measures over long time periods; (2) inevitable gaps in data limiting the post-processing; (3) the need for recording other environmental variables in the same period and at a coherent sampling frequency. To record a high-frequency and long-term turbidity dataset, an automatic monitoring network (MAGEST) has been implemented in the Gironde estuary, a macrotidal and highly turbid system in the South-West France, in 2004. This 10-year turbidity time series is rather unique in European estuaries, enabling the evaluation of SS dynamics at all the significant time scales in one single analysis of the dataset. To achieve this, several methodologies of data analysis using different approaches are available, but their relevance, especially for the more recently developed ones, is almost unexplored. In this work, we present the test of four spectral techniques to the analysis of a high-frequency turbidity time series of an estuary such as the Gironde, to discuss advantages and limitations of each method. We compare the Power Spectral Analysis (PSA), the Singular Spectral Analysis (SSA), the Wavelet Transform (WT) and the Empirical Mode Decomposition (EMD). Advantages and limitations of each method are evaluated on the basis of five criteria: efficiency for incomplete time series, appropriateness for time-varying analysis, ability to recognize processes without the need of complementary environmental variables, capacity to calculate the relative importance of processes, and capacity to identify long

  13. THE CHARACTERISTIC OF MARINE ENVIRONMENT IN LINGDINGYANG ESTUARY

    2001-01-01

    Hydrologic features, load of main pollutants and current condition of water quality in Lingdingyang Estu ary are discussed by references and monitoring data. Affected by topography, runoff and tide, its dynamic condition is very complicated. Different water areas have different hydrologic features. The topography under the water of Lingdingyang Estuary is higher in the northwest than that in the southeast. The shoal alternates with the deep trough with in the bay. The distribution of the salinity and the contents of the mud and the main pollutants tally with the topography tendency. Change in water quality goes through four stages. Current condition of water quality is fairly good. Inorganic nitrogen is the primary pollutant, and then phosphorus. Rich in nutrition of nitrogen and phosphorus become a more and more prominent problem.

  14. Guidelines for determining inputs of inorganic contaminants into estuaries

    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

  15. Hydrodynamic and Salinity Intrusion Model in Selangor River Estuary

    Haron, N. F.; Tahir, W.

    2016-07-01

    A multi-dimensional hydrodynamic and transport model has been used to develop the hydrodynamic and salinity intrusion model for Selangor River Estuary. Delft3D-FLOW was applied to the study area using a curvilinear, boundary fitted grid. External boundary forces included ocean water level, salinity, and stream flow. The hydrodynamic and salinity transport used for the simulation was calibrated and confirmed using data on November 2005 and from May to June 2014. A 13-day period for November 2005 data and a 6-day period of May to June 2014 data were chosen as the calibration and confirmation period because of the availability of data from the field-monitoring program conducted. From the calibration results, it shows that the model was well suited to predict the hydrodynamic and salinity intrusion characteristics of the study area.

  16. 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...

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

    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-kőlyuk Cave provided less species, which couldbe related to their advanced touristic and industrial utilization.

  18. Modern tectonic stress field in Southwest Yunnan, China

    谢富仁; 苏刚; 崔效锋; 舒赛兵; 赵建涛

    2001-01-01

    By means of inversion of fault slip data, the parameters of 20 tectonic stress tensors in Southwest Yunnan region are determined. Compared with the average stress field of the region obtained from focal mechanism solutions, the following characteristics of modern tectonic stress field in this region are obtained. From the west of Zhenyuan- Yingpanshan fault to the south of Longling fault zone, the maximum compressional stress is in NNE direction and the stress regime is mainly of strike-slip type. In Longling fault zone and the area north to it, the direction of maximum compressional stress is near-NS or NNW, the stress regime is of strike-slip type.

  19. Rare earth element analysis indicates micropollutants in an urban estuary

    Mohajerin, T. J.; Johannesson, K. H.; Kolker, A.; Burdige, D. J.; Chevis, D.

    2011-12-01

    Rare earth element analysis of Bayou Bienvenue waters shows anomalously high gadolinium, Gd, concentrations relative to its nearest neighbors in the REE series, europium and terbium. The anomalously high Gd concentrations indicate anthropogenic input from waste-water treatment plants in the area as anthropogenic Gd input can be traced back to its use as a contrast agent in magnetic resonance imaging in hospitals. Others have shown that anomalously high levels of Gd in natural waters are likely to be associated with other micropollutants that also occur in hospital effluent and that are not removed in the wastewater treatment process, including pharmaceuticals in the form of steroids, antihistamines, and antibiotics. Estuaries serve as many important ecological roles and have been shown to act as a filter for pollutants. To better understand the transport, biogeochemical cycling, and ultimate fate of trace elements in estuaries, I collected surface water samples from Bayou Bienvenue, a wetland triangle that covers an area of 427 acres directly adjacent to New Orleans, Louisiana. Water samples from Bayou Bienvenue were collected along the salinity gradient and subsequently filtered through progressively smaller pore-size filters. The resulting fractions were analyzed for trace element concentions, including the REEs, by magnetic sector ICP-MS. The attached figure shows the Gd anomaly present in the particulate (>0.45μm) fraction. Upper continental crust (UCC)-normalized plots of colloidal REEs (0.02μm - 0.45μm) fraction is lacking this anomaly indicating anthropogenic Gd is found chiefly in the particulate fraction in Bayou Bienvenue. No clear relationship between Gd concentration and salinity was apparent.

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

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

    , not well understood due to complex interactions between various physical, chemical and biological processes that govern the 3    composition, distribution and processing of OM in estuaries (Deegan et al. 1985; Sharp et al. 1986; Hobbie 2000). Sources... the proportional contribution from each source, and (ii) to identify the controlling mechanism for distribution and preservation of OM in sediments of the Godavari estuary. We hypothesize that there are several physical and biological processes controlling...

  1. Reproductive biology of Sciades herzbergii (Siluriformes: Ariidae) in a tropical estuary in Brazil

    Queiroga, Fernando R.; Jéssica E. Golzio; Raphaela B. dos Santos; Tayná O. Martins; Ana Lúcia Vendel

    2012-01-01

    The present study investigated the reproductive biology of Sciades herzbergii in the Paraíba do Norte River Estuary, Brazil. We aimed to characterize the reproduction of the species with respect to sex ratio, spawning season, condition factor and length at first maturity. Specimens were captured between August 2009 and July 2010 in a stretch of the main channel of the estuary. In the laboratory, they were measured, weighed and macroscopically classified with regard to sex and gonad developmen...

  2. Estimating minimum environmental flow requirements for well-mixed estuaries in Spain

    Peñas, Francisco J.; Juanes, José A.; Galván, Cristina; Medina, Raúl; Castanedo, Sonia; Álvarez, César; Bárcena, Javier F.

    2013-12-01

    Following the principles of the European Water Framework Directive, the current Spanish water management legislation requires the definition of the environmental flow regimes for all water bodies, including estuaries. The scientific community has tried to answer the question of how much freshwater an estuary needs since the mid-1970s, resulting in the development of several methodologies and approaches in different parts of the world. However the ability to reproduce most of these approaches is difficult due to the scarcity of required data and also to the differences between the studied estuaries. In this paper, we present a methodology to calculate environmental flow regimes in well-mixed estuaries based on the numerical modelling of salinity and which takes into account the seasonal climatic and hydrologic pattern of the catchment. The approach follows three sequential steps: 1) Definition of reference conditions based on the unaltered salinity patterns and zoning of the estuary, 2) definition of salinity thresholds and 3) calculation of the minimum flows required to satisfy these thresholds. The application of the methodology to five estuaries on the northern coast of Spain has highlighted the importance of considering the hydrological variability and the division of the estuary into homogeneous zones. Moreover, the studies carried out demonstrate the ineffectiveness of river specific methodologies when used to define environmental flow regimes in several estuaries and periods, and the need to apply specific methodologies. The methodology is based on the principles defined by other already tested approaches, but its greatest advantage lies in the ability to be applied to large scales, when physical and biological data is scarce.

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

    Nandadeep U. Fal Dessai

    2013-01-01

    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 we...

  4. Hydrographic and dissolved oxygen variability in a seasonal Pacific Northwest estuary

    Sutherland, David A.; O'Neill, Molly A.

    2016-04-01

    Hypoxia is an issue of growing concern for coastal communities. In the California Current System, a prototypical eastern boundary current, attention has been focused on explaining the trend of increasing shelf hypoxia. Despite the regional focus on hypoxia in eastern boundary regions, relatively few studies have examined smaller estuarine systems. Here, we present results from an observational study in Coos Bay, a small estuary on the southern Oregon coast, subject to seasonal upwelling/downwelling winds, strong tides, and wide fluctuations in freshwater input. Coos Bay exhibits characteristics of a salt-wedge type estuary under high river discharge conditions (>150 m3 s-1), a well-mixed estuary under low discharge conditions (0-30 m3 s-1), and partially-mixed estuary during times of moderate discharge (30-150 m3 s-1). The observed vertical stratification and along-estuary salinity gradients correlate significantly with river discharge and tidal forcing. Despite a strong coupling with coastal waters where hypoxia has been present, we do not find evidence for pervasive hypoxia in Coos Bay. We find that upwelling on the shelf advects low dissolved oxygen water into the estuary on synoptic timescales. Early in the upwelling season (April and May), dissolved oxygen minima are found at the estuary mouth, while later in the summer (September), dissolved oxygen minima are found at the riverine end, presumably due to decreased discharge and increased productivity. However, in a given year, the overall strength of the upwelling season is not a good predictor of low dissolved oxygen levels in the estuary.

  5. Sediment abiotic patterns in current and newly created intertidal habitats from an impacted estuary

    Beauchard, O.; Teuchies, J.; Jacobs, S; E. Struyf; Van der Spiet, T.; P. Meire

    2014-01-01

    The controlled reduced tide system (CRT) is a new technique for restoring tidal marshes and is being tested in the Schelde estuary (Belgium). Biogeochemical processes within a CRT were hypothesized to support and improve several estuarine functions such as sediment trapping and nutrient burial. In 2006, the first pilot CRT was implemented in the freshwater zone of the estuary. Fifteen sediment physicochemical descriptors were intensively monitored over 3 years in the newly created CRT and in ...

  6. Nitrification in the Schelde estuary: methodological aspects and factors influencing its activity

    Bie, M.J.M. de; Starink, M.; Boschker, H.T.S.; Peene, J.J.; Laanbroek, H. J.

    2002-01-01

    We present a 15-month dataset on nitrification measurements in the Schelde estuary (Belgium and The Netherlands). Nitrification was estimated using the N-serve sensitive dark 14C-bicarbonate incorporation technique. A peak of nitrification activity was observed in the freshwater part of the estuary. Downstream from this peak, nitrification declined, probably because of ammonium limitation. A range of nitrification inhibitors was tested on both a Nitrosomonas europaea culture and estuarine sam...

  7. Environmental Settings and Harmful Algal Blooms in the Sea Area Adjacent to the Changjiang River Estuary

    Zhou, Mingjiang

    2010-01-01

    The characteristics of the environmental settings of the sea area adjacent to the Changjiang River estuary include complex currents and water masses, the diluted water plume and its redirection, upwelling, front, and nutrients and their sources. The Changjiang River estuary characteristics also include the phytoplankton community, which can affect the growth, migration, assembling, resting and competition of algae to form red tides in this area.. The features of red tide events recorded in th...

  8. OCCURRENCE OF Charybdis hellerii (Milne Edwards, 1867 (CRUSTACEA, DECAPODA, PORTUNIDAE IN AN AMAZONIAN ESTUARY.

    Alessandra Batista Bentes

    2013-12-01

    Full Text Available For the first time specimens of Charybdis hellerii (Milne Edwards 1867, an Indo Pacific specie, were caught in Amazon estuary, Bragança, Pará, North of Brazil. Palavras-chave: Crustacea, Charybdis hellerii , Amazonian Estuary. DOI: http://dx.doi.org/10.18561/2179-5746/biotaamazonia.v3n3p181-184

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

    2011-01-01

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

  10. Overview of trace metal contamination in the Scheldt estuary and effect of regulatory measures

    Baeyens, W.F.J.; Leermakers, M; De Gieter, M.; Nguyen, H.L.; Parmentier, K.; Panutrakul, S.; Elskens, M.

    2005-01-01

    Seasonally, dissolved and particulate metal concentrations in the Scheldt estuary were assessed over a period of 4 years (1995–1998). High quality data were obtained following stringent analytical protocols for each step: sampling, sample treatment, sample storage and analysis. Of the 5 trace metals, Ni showed the most conservative behaviour, while Cd and Cu were clearly transferred from the particulate to the dissolved phase in the middle estuary. A substantial part of the particulate metals...

  11. Influence of benthic macrofauna community shifts on ecosystem functioning in shallow estuaries

    Kristensen, Erik; Delefosse, Matthieu; Quintana, Cintia O.; Flindt, Mogens R.; Valdemarsen, Thomas

    2014-01-01

    We aim at identifying how ecosystem functioning in shallow estuaries is affected by rapid shifts in benthic fauna communities. We use the shallow estuary, Odense Fjord, Denmark, as a case study to test our hypotheses that (1) shifts in benthic fauna composition and species functional traits affect biogeochemical cycling with cascading effects on the ecological functioning, which may (2) modulate primary productivity in the overlying water column with feedbacks to the benthic system. Odense Fj...

  12. Recherche de la contamination en cadmium de la Gironde

    Boutier, Bernard

    1984-01-01

    Depuis sa création, le RNO matière vivante surveille les niveaux de présence des métaux lourds chez les mollusques filtreurs du littoral français (Crassostrea gigas, Mytilus edulis). Par leur aptitude à accumuler certains polluants dans leurs tissus, ces animaux donnent en effet de bonnes indications sur la qualité du milieu où ils vivent, tout en atténuant notablement les variations à court terme caractéristiques du milieu aquatique (PHILLIPS DJH, 1976-1977 ; DARRACOTT A. et WATLING H. , 197...

  13. Developing a coupled analytical model for analyzing salt intrusion in alluvial estuaries

    Savenije, H.; CAI, H.; Gisen, J.

    2013-12-01

    A predictive assessment technique to estimate the salt intrusion length and longitudinal salinity distribution in estuaries is important for policy makers and managers to maintain a healthy estuarine environment. In this study, the salt intrusion model of Savenije (2005, 2012) is applied and coupled to an explicit solution for tidal dynamics developed by Cai and Savenije (2013). The objective of the coupling is to reduce the number of calibration parameters, which subsequently strengthens the reliability of the salt intrusion model. Moreover, the fully analytical treatment allows assessing the effect of model forcing (i.e., tide and river discharge) and geometry adjustments (e.g., by dredging) on system performance. The coupled model has been applied to a wide range of estuaries, and the result shows that the correspondence between analytical estimations and observations is very good. As a result, the coupled model is a useful tool for decision makers to obtain first order estimates of salt intrusion in estuaries based on a minimum of information required. References Savenije, H.H.G. (2005), Salinity and Tides in Alluvial Estuaries, Elsevier. Savenije, H.H.G. (2012), Salinity and Tides in Alluvial Estuaries, completely revised 2nd edition, www.salinityandtides.com. Cai, H., and H. H. G. Savenije (2013), Asymptotic behavior of tidal damping in alluvial estuaries, Journal of Geophysical Research, submitted.

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

    Regla Duthit Somoza

    2011-04-01

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

  15. Spatial distribution and risk assessment of heavy metals in sediments of Shuangtaizi estuary, China

    Highlights: • Five heavy metals are analyzed in the sediments from Shuangtaizi estuary. • Particle size of the sediment effects the concentration of heavy metals. • Pb, Cu, Zn and Hg pose low ecological risks in the Shuangtaizi estuary. • Heavy metal pollution in Shuangtaizi estuary is mainly dominated by Cd. - Abstract: In order to evaluate the spatial distribution and potential ecological risk of Pb, Cu, Zn, Cd, and Hg, the surface sediments were collected from 18 sites in the Shuangtaizi estuary. The concentrations of Pb, Cu, Zn, Cd, and Hg were analyzed by atomic absorption spectrophotometry and atomic fluorescence spectrometry after digestion. The particle sizes of the sediments were analyzed using a laser diffraction particle size analyzer. The results show that the heavy metal contents in the sediments are observed in the following order: Zn (18.25–126.75 mg/kg) > Pb (4.38–9.65 mg/kg) > Cu (1.80–17.68 mg/kg) > Cd (0.241–0.764 mg/kg) > Hg (0.007–0.021 mg/kg). In comparison with the concentrations of heavy metals in other regions, the concentrations of Pb, Cu, and Zn in the Shuangtaizi estuary are generally low, and the Cd concentrations are close to those reported in other regions. Both the potential ecological risk index and the geoaccumulation index reveal that the heavy metal pollution in Shuangtaizi estuary is mainly dominated by Cd

  16. A classification of U.S. estuaries based on physical and hydrologic attributes

    Engle, V.D.; Kurtz, J.C.; Smith, L.M.; Chancy, C.; Bourgeois, P.

    2007-01-01

    A classification of U.S. estuaries is presented based on estuarine characteristics that have been identified as important for quantifying stressor-response relationships in coastal systems. Estuaries within a class have similar physical and hydrologic characteristics and would be expected to demonstrate similar biological responses to stressor loads from the adjacent watersheds. Nine classes of estuaries were identified by applying cluster analysis to a database for 138 U.S. estuarine drainage areas. The database included physical measures of estuarine areas, depth and volume, as well as hydrologic parameters (i.e., tide height, tidal prism volume, freshwater inflow rates, salinity, and temperature). The ability of an estuary to dilute or flush pollutants can be estimated using physical and hydrologic properties such as volume, bathymetry, freshwater inflow and tidal exchange rates which influence residence time and affect pollutant loading rates. Thus, physical and hydrologic characteristics can be used to estimate the susceptibility of estuaries to pollutant effects. This classification of estuaries can be used by natural resource managers to describe and inventory coastal systems, understand stressor impacts, predict which systems are most sensitive to stressors, and manage and protect coastal resources. ?? Springer Science+Business Media B.V. 2007.

  17. Metabarcoding of benthic eukaryote communities predicts the ecological condition of estuaries

    DNA-derived measurements of biological composition have the potential to produce data covering all of life, and provide a tantalizing proposition for researchers and managers. We used metabarcoding to compare benthic eukaryote composition from five estuaries of varying condition. In contrast to traditional studies, we found biotic richness was greatest in the most disturbed estuary, with this being due to the large volume of extraneous material (i.e. run-off from aquaculture, agriculture and other catchment activities) being deposited in the system. In addition, we found strong correlations between composition and a number of environmental variables, including nutrients, pH and turbidity. A wide range of taxa responded to these environmental gradients, providing new insights into their sensitivities to natural and anthropogenic stressors. Metabarcoding has the capacity to bolster current monitoring techniques, enabling the decisions regarding ecological condition to be based on a more holistic view of biodiversity. - Highlights: • We used metabarcoding to examine the benthic eukaryote composition of five estuaries. • Biotic richness (based on MOTUs) was greater in the most impacted estuary. • Similarities among estuaries reflected their environmental condition. • Composition was strongly correlated with nutrients, turbidity and pH. • Metabarcoding can provide fast, comprehensive and ecologically informative data. - Using metabarcoding we were able discriminate benthos from five estuaries, and identify those taxa which responded negatively and positivity to the key environmental stressors

  18. Potential Impacts and Management Implications of Climate Change on Tampa Bay Estuary Critical Coastal Habitats

    Sherwood, Edward T.; Greening, Holly S.

    2014-02-01

    The Tampa Bay estuary is a unique and valued ecosystem that currently thrives between subtropical and temperate climates along Florida's west-central coast. The watershed is considered urbanized (42 % lands developed); however, a suite of critical coastal habitats still persists. Current management efforts are focused toward restoring the historic balance of these habitat types to a benchmark 1950s period. We have modeled the anticipated changes to a suite of habitats within the Tampa Bay estuary using the sea level affecting marshes model under various sea level rise (SLR) scenarios. Modeled changes to the distribution and coverage of mangrove habitats within the estuary are expected to dominate the overall proportions of future critical coastal habitats. Modeled losses in salt marsh, salt barren, and coastal freshwater wetlands by 2100 will significantly affect the progress achieved in "Restoring the Balance" of these habitat types over recent periods. Future land management and acquisition priorities within the Tampa Bay estuary should consider the impending effects of both continued urbanization within the watershed and climate change. This requires the recognition that: (1) the Tampa Bay estuary is trending towards a mangrove-dominated system; (2) the current management paradigm of "Restoring the Balance" may no longer provide realistic, attainable goals; (3) restoration that creates habitat mosaics will prove more resilient in the future; and (4) establishing subtidal and upslope "refugia" may be a future strategy in this urbanized estuary to allow sensitive habitat types (e.g., seagrass and salt barren) to persist under anticipated climate change and SLR impacts.

  19. Dynamics of the Acartia genus (Calanoida: Copepoda) in a temperate shallow estuary (the Mondego estuary) on the western coast of Portugal

    Azeiterio, Ulisses Miranda; Maques, Sónia Cotrim; Viera, Luís Miguel Russo; Pastorinho, Manuel Ramiro Dias; Ré, Pedro Alfaia Barcia; Pereira, Mário Jorge; Morgado, Fernando Manuel Raposo

    2005-01-01

    The purpose of this work was to review the dynamics of the Acartia species in the Mondego estuary (a temperate North-Atlantic shallow estuary in Western Portugal) in a genus integrated perspective. The Acartia genus is represented in the system by the species Acartia clausi and Acartia tonsa; the samples were taken between July 1999 and June 2000, with 63 and 125 µm mesh size nets, and between January 2003 and January 2004, with a 335 µm mesh size net, in the downstream and upstream areas of ...

  20. Role of different salt marsh plants on metal retention in an urban estuary (Lima estuary, NW Portugal)

    Almeida, C. M. R.; Mucha, Ana P.; Teresa Vasconcelos, M.

    2011-01-01

    The aim of the present work was to understand the role different salt marsh plants on metal distribution and retention in the Lima River estuary (NW Portugal), which to our knowledge have not been ascertained in this area yet. The knowledge of these differences is an important requirement for the development of appropriate management strategies, and is poorly described for Eurosiberian estuaries, like the one selected. In addition it is important to understand the difference among introduced and native salt marsh plants. In this work, metal levels (Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) were surveyed (by atomic absorption spectrometry) in sediments from sites vegetated with Juncus maritimus, Spartina patens, Phragmites australis and Triglochin striata (rhizo-sediments), in non-vegetated sediments and in the different tissues of the plants (roots, rhizomes and aerial shoots). In general, rhizo-sediments had higher metal concentrations than non-vegetated sediments, a feature that seems common to sediments colonized by salt marsh plants of different estuarine areas. All plants concentrated metals, at least Cd, Cu and Zn (and Pb for T. striata) in their belowground structures ([ M] belowground tissues/[ M] non-vegetated sediment > 1). However, when considered per unit of salt marsh area, the different selected plants played a different role on sediment metal distribution and retention. Triglochin striata retained a significant metal burden in it belowground structures (root plus rhizomes) acting like a possible phyto-stabilizer, whereas P. australis had an higher metal burden in aboveground tissues acting as a possible phyto-extractor. As for J. maritimus and S. patens, metal burden distribution between above and belowground structures depended on the metal, with J. maritimus retaining, for instance, much more Cd and Cu in the aboveground than in the belowground structures. Therefore, the presence of invasive and exotic plants in some areas of the salt marsh may

  1. Studies on length-weight relationship of Gerres filamentosus Cuvier from the estuaries of the southern Karnataka coast

    Udupa, K.S.; Averel, M.; Raghavendra, C.H.; Bevinahalli, V.; Reddy, A; Kumarswamy, A.R.

    2003-01-01

    Random samples of Gerres filamentosus Cuvier from the Netravathi-Gurpur, Mulky, Kallayanapura, Mabukala and Kundapura estuaries of the southern Karnataka Coast were collected in the years 2000, 2001 and 2002, and length-weight relationships for each estuary were derived using multiple linear regression technique with one dummy variable. Hence, combined or sex-wise length-weight relationships were obtained after testing for homogeneity and isometric growth condition of fishes for each estuary ...

  2. Autotrophic and heterotrophic food sources of copepods in the Scheldt estuary as traced by stable C and N isotopes

    L. De Brabandere

    2005-01-01

    Estuaries draining densely populated watersheds experience significant anthropogenic pressure and sustain large autotrophic and heterotrophic production owing to an increased input of nutrients and organic matter. Polluted estuaries are often net heterotrophic systems. Our objective was to study the relative contributionof autotrophic and heterotrophic food webs in sustaining the high productivity of pelagic estuarine ecosystems along the estuarine gradient of the Scheldt estuary. We concentr...

  3. Polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in sediments from the Mersey Estuary, U.K.

    Vane, C.H.; Harrison, I; Kim, A W

    2007-01-01

    Sediments from the Mersey Estuary were analysed for polycylic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs). Total PAH concentrations ranged from 626 to 3766 μg/kg and total PCB concentrations ranged from 36 to 1409 μg/kg. These concentrations are intermediate in comparison to other U.K estuaries with similar histories of industrialisation and urbanisation. The distribution of individual PAHs were consistent throughout the Mersey Estuary, this together with molecular indic...

  4. Intense Southwest Florida hurricane landfalls over the past 1000 years

    Ercolani, Christian; Muller, Joanne; Collins, Jennifer; Savarese, Michael; Squiccimara, Louis

    2015-10-01

    Recent research has proposed that human-induced sea surface temperature (SST) warming has led to an increase in the intensity of hurricanes over the past 30 years. However, this notion has been challenged on the basis that the instrumental record is too short and unreliable to reveal long-term trends in hurricane activity. This study addresses this limitation by investigating hurricane-induced overwash deposits (paleotempestites) behind a barrier island in Naples, FL, USA. Paleotempestologic proxies including grain size, percent calcium carbonate, and fossil shells species were used to distinguish overwash events in two sediment cores spanning the last one thousand years. Two prominent paleotempestites were observed in the top 20 cm of both cores: the first identified as Hurricane Donna in 1960 whereas an older paleotempestite (1900-1930) could represent one of three documented storms in the early 1900s. An active period of hurricane overwash from 1000 to 500 yrs. BP and an inactive period from 500 to 150 yrs. BP correlate with reconstructed SSTs from the Main Development Region (MDR) of the North Atlantic Ocean. We observe an increased number of paleotempestites when MDR SSTs are warmer, coinciding with the Medieval Warm Period, and very few paleotempestites when MDR SSTs are cooler, coinciding with the Little Ice Age. Results from this initial Southwest Florida study indicate that MDR SSTs have been a key long-term climate driver of intense Southwest Florida hurricane strikes.

  5. Modelling Pseudo-nitzschia events off southwest Ireland

    Cusack, Caroline; Mouriño, Helena; Moita, Maria Teresa; Silke, Joe

    2015-11-01

    Toxic and non-toxic Pseudo-nitzschia blooms are common in coastal waters worldwide including Ireland. Off southwest Ireland, the timing of blooms on a weekly scale is highly variable, while the seasonal pattern is more regular with a bimodal distribution. Upwelling conditions are closely linked to Pseudo-nitzschia blooms. The work presented here describes a mathematical model, a Zero-Inflated Negative Binomial Model, employed to forecast the onset, abundance and duration of Pseudo-nitzschia blooms in the bays of southwest Ireland. Variables used in the model included field observations of Pseudo-nitzschia, sea surface temperature and wind. The estimated model reveals that, on average, cell levels on a given day depend on sea surface temperature, the value of a wind index on the previous day and the number of Pseudo-nitzschia in the water the previous week. The model forecast performed well for the onset and duration of blooms. However, the magnitude of blooms was sometimes underestimated by the model.

  6. Allergic skin test reactivity to marijuana in the Southwest.

    Freeman, G L

    1983-06-01

    In a general allergy consultation practice in Arizona and western New Mexico, 129 patients were tested for immediate hypersensitivity skin test reactivity to marijuana pollen and tobacco leaf, as well as to a battery of other antigens. In all, 90 patients were diagnosed as allergic (atopic) and, of these, 63 (70 percent) were found to be skin test reactive to marijuana pollen and 18 (20 percent) to tobacco leaf. The incidence of skin test reactivity to marijuana was not significantly different for persons living at low, middle or high elevations throughout the Southwest. Marijuana sensitivity occurred in patients who were, in general, also sensitive to a variety of other airborne plant pollens. There was no close correlation, however, between sensitivity to marijuana pollen and sensitivity to pollens from elm, mulberry, hop and stinging nettle, which are botanically related to marijuana. The data suggest that marijuana pollen may be a relatively common airborne pollen pollutant in the Southwest, allergic persons being sensitized through inhalation. If this is confirmed by further studies, then clinical investigation of marijuana hyposensitization (immunotherapy) may be warranted. This is in contrast to tobacco allergy for which simple avoidance is recommended. PMID:6613109

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

    Luan, Hua Long; Ding, Ping Xing; Wang, Zheng Bing; Ge, Jian Zhong; Yang, Shi Lun

    2016-07-01

    The Yangtze Estuary in China has been intensively influenced by human activities including altered river and sediment discharges in its catchment and local engineering projects in the estuary over the past half century. River sediment discharge has significantly decreased since the 1980s because of upstream dam construction and water-soil conservation. We analyzed bathymetric data from the Yangtze Estuary between 1958 and 2010 and divided the entire estuary into two sections: inner estuary and mouth bar area. The deposition and erosion pattern exhibited strong temporal and spatial variations. The inner estuary and mouth bar area underwent different changes. The inner estuary was altered from sedimentation to erosion primarily at an intermediate depth (5-15 m) along with river sediment decline. In contrast, the mouth bar area showed continued accretion throughout the study period. The frequent river floods during the 1990s and simultaneously decreasing river sediment probably induced the peak erosion of the inner estuary in 1986-1997. We conclude that both sediment discharge and river flood events played important roles in the decadal morphological evolution of the Yangtze Estuary. Regarding the dredged sediment, the highest net accretion rate occurred in the North Passage where jetties and groins were constructed to regulate the navigation channel in 1997-2010. In this period, the jetties induced enhanced deposition at the East Hengsha Mudflat and the high accretion rate within the mouth bar area was maintained. The impacts of estuarine engineering projects on morphological change extended beyond their sites.

  8. Dissolved inorganic carbon dynamics and CO2 atmospheric exchanges in the inner and outer Scheldt estuary

    Borges, A. V.; Frankignoulle, M.

    2002-01-01

    Since 1992, the Chemical Oceanography Unit of the University of Liège has carried out on a regular basis field cruises in the Scheldt inner estuary and the river plume (outer estuary), during which were measured: pH, total alkalinity, dissolved inorganic carbon, partial pressure of CO2 (pCO2), dissolved oxygen and atmospheric flux of CO2. In the inner Scheldt estuary, pCO2 values in the upper estuary can be as high as 9000 ppm that is about 25 times the value of atmospheric equilibrium (pres...

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

    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

  10. Tidal wetland conservation and restoration for flood mitigation in estuaries and deltas: examples and global potential

    Temmerman, Stijn; Smolders, Sven; Stark, Jeroen; meire, patrick

    2014-05-01

    Low-lying and densely populated deltas and estuaries are world widely exposed to flood risks caused by storm surges. On the one hand, global change is increasing these flood risks through accelerating sea level rise and increasing storm intensity, but on the other hand, local-scale human impacts on deltas and estuaries are in many cases even more increasing the vulnerability to floods. Here we address the degradation and reclamation of tidal wetlands (i.e. salt marshes in the temperate zone and mangroves in the tropical zone) as a major source for increasing vulnerability to flooding of estuaries and deltas. Firstly, we present examples of flood mitigation by tidal wetland conservation and restoration, and secondly we explore the potentials and limitations for global application of this approach of ecosystem-based flood defense (see Temmerman et al. 2013). First, we use the Scheldt estuary (SW Netherlands and Belgium) as an example where historic wetland reclamation has importantly contributed to increasing flood risks, and where tidal marsh restoration on the previously reclaimed land is nowadays brought into large-scale practice as an essential part of the flood defense system. Based on data and hydrodynamic modelling, we show that large-scale historic marsh reclamation has largely reduced the water storage capacity of the estuary and has reduced the friction to propagating flood waves, resulting in an important landward increase of tidal and storm surge levels. Hydrodynamic model scenarios demonstrate how tidal and storm surge propagation through the estuary are affected by tidal marsh properties, including the surface area, elevation, vegetation and position of marshes along the estuary. We show that nowadays tidal wetland creation on previously reclaimed land is applied as an essential part of the flood defense system along the Scheldt estuary. Secondly, a global analysis is presented of the potential application of tidal wetlands in flood mitigation in

  11. 78 FR 64264 - Receipt of Noise Compatibility Program and Request for Review; Southwest Florida International...

    2013-10-28

    ... Federal Aviation Administration Receipt of Noise Compatibility Program and Request for Review; Southwest... Noise Compatibility Program that was submitted for Southwest Florida International Airport under the provisions of 49 U.S.C. 47504 et seq (the Aviation Safety and Noise Abatement Act hereinafter referred to...

  12. Morphological and Morphometrical Description of Trichostrongylus Species Isolated from Domestic Ruminants in Khuzestan Province, Southwest Iran

    Ghasemikhah, R; Mirhendi, H; Kia, EB; Mowlavi, Gh; Sarmadian, H; B Meshgi; B Golestan; I Mobedi

    2011-01-01

    Backgrounds Genus Trichostrongylus (Nematoda: Trichostrongylidae) is one of the most important zoonotic nematodes with wide geographic distribution in the world. The purpose of the present study was to describe morphological and morphometrical characteristics of male Trichostrongylus species, currently prevalent in domestic ruminants of Khuzestan Province, southwest Iran. Methods Gastro-intestinal organs of 1600 sheep, goats, cattle, and buffalos, slaughtered in Khuzestan Province, southwest ...

  13. 76 FR 15307 - Notice of Staff Attendance at Southwest Power Pool Strategic Planning Committee Meeting

    2011-03-21

    ... Energy Regulatory Commission Notice of Staff Attendance at Southwest Power Pool Strategic Planning Committee Meeting The Federal Energy Regulatory Commission hereby gives notice that members of its staff may attend the meeting of the Southwest Power Pool, Inc. (SPP) Strategic Planning Committee (SPC), as...

  14. Chemical mass balance source apportionment of fine and PM10 in the Desert Southwest, USA

    The Desert Southwest Coarse Particulate Matter Study was undertaken in Pinal County, Arizona, to better understand the origin and impact of sources of fine and coarse particulate matter (PM) in rural, arid regions of the U.S. southwestern desert. The desert southwest experiences ...

  15. 76 FR 8730 - Desert Southwest Customer Service Region-Rate Order No. WAPA-151

    2011-02-15

    ... CFR part 903) were published on September 18, 1985 (50 FR 37835). After review of public comments, and... Area Power Administration Desert Southwest Customer Service Region-Rate Order No. WAPA-151 AGENCY..., Regional Manager, Desert Southwest Customer Service Region, Western Area Power Administration, 615...

  16. U.S. Border Patrol Fiscal Year Statistics Southwest border sector deaths - FY 1998 through FY 2013

    Department of Homeland Security — Southwest Border Sectors include: Del Rio, El Centro, El Paso, Laredo, Rio Grande Valley, San Diego, Tucson, Yuma Southwest Border Deaths By Fiscal Year (Oct. 1st...

  17. Polychaete richness and abundance enhanced in anthropogenically modified estuaries despite high concentrations of toxic contaminants.

    Katherine A Dafforn

    Full Text Available Ecological communities are increasingly exposed to multiple chemical and physical stressors, but distinguishing anthropogenic impacts from other environmental drivers remains challenging. Rarely are multiple stressors investigated in replicated studies over large spatial scales (>1000 kms or supported with manipulations that are necessary to interpret ecological patterns. We measured the composition of sediment infaunal communities in relation to anthropogenic and natural stressors at multiple sites within seven estuaries. We observed increases in the richness and abundance of polychaete worms in heavily modified estuaries with severe metal contamination, but no changes in the diversity or abundance of other taxa. Estuaries in which toxic contaminants were elevated also showed evidence of organic enrichment. We hypothesised that the observed response of polychaetes was not a 'positive' response to toxic contamination or a reduction in biotic competition, but due to high levels of nutrients in heavily modified estuaries driving productivity in the water column and enriching the sediment over large spatial scales. We deployed defaunated field-collected sediments from the surveyed estuaries in a small scale experiment, but observed no effects of sediment characteristics (toxic or enriching. Furthermore, invertebrate recruitment instead reflected the low diversity and abundance observed during field surveys of this relatively 'pristine' estuary. This suggests that differences observed in the survey are not a direct consequence of sediment characteristics (even severe metal contamination but are related to parameters that covary with estuary modification such as enhanced productivity from nutrient inputs and the diversity of the local species pool. This has implications for the interpretation of diversity measures in large-scale monitoring studies in which the observed patterns may be strongly influenced by many factors that covary with anthropogenic

  18. Vulnerability Assessments in Support of the Climate Ready Estuaries Program: A Novel Approach Using Expert Judgment, Volume I: Results for the San Francisco Estuary Partnership (Final Report)

    As part of the Climate Ready Estuaries (CRE) program, the Global Change Research Program (GCRP) in the National Center for Environmental Assessment, Office of Research and Development at the U.S. Environmental Protection Agency has prepared this draft report exploring a new metho...

  19. Remote Sensing Technologies for Estuary Research and Management (Invited)

    Hestir, E. L.; Ustin, S.; Khanna, S.; Botha, E.; Santos, M. J.; Anstee, J.; Greenberg, J. A.

    2013-12-01

    Estuarine ecosystems and their biogeochemical processes are extremely vulnerable to climate and environmental changes, and are threatened by sea level rise and upstream activities such as land use/land cover and hydrological changes. Despite the recognized threat to estuaries, most aspects of how change will affect estuaries are not well understood due to the poorly resolved understanding of the complex physical, chemical and biological processes and their interactions in estuarine systems. New and innovative remote sensing technologies such as high spectral resolution optical and thermal imagers and lidar, microwave radiometers and radar imagers enable measurements of key environmental parameters needed to establish baseline conditions and improve modeling efforts. Radar's sensitivity to water provides information about water height and velocity, channel geometry and wetland inundation. Water surface temperature and salinity and can be measured from microwave radiometry, and when combined with radar-derived information can provide information about estuarine hydrodynamics. Optical and thermal hyperspectral imagers provide information about sediment, plant and water chemistry including chlorophyll, dissolved organic matter and mineralogical composition. Lidar can measure bathymetry, microtopography and emergent plant structure. Plant functional types, wetland community distributions, turbidity, suspended and deposited sediments, dissolved organic matter, water column chlorophyll and phytoplankton functional types may be estimated from these measurements. Innovative deployment of advanced remote sensing technologies on airborne and submersible un-piloted platforms provides temporally and spatially continuous measurement in temporally dynamic and spatially complex tidal systems. Through biophysically-based retrievals, these technologies provide direct measurement of physical, biological and biogeochemical conditions that can be used as models to understand estuarine

  20. Sticky stuff! Seasonal flocculation in a hypertidal estuary

    Todd, David; Souza, Alejandro; Jago, Colin

    2013-04-01

    Suspended particular matter (SPM) is a highly variable and important aspect of estuarine systems. It determines turbidity; impacting water quality, generates benthic fluff, modifies biogeochemical exchanges, and constrains primary productivity. Further, SPM carries biogeochemical components (e.g. carbon, nitrogen), deciding the fates of anthropogenic system inputs. Outside of the non-cohesive fraction (sand), little is known of the properties of estuarine SPM (i.e. sizes, densities, settling velocities) and how these impact sedimentation as most SPM is in the form of flocs (aggregates of dead and living organic matter, cohesive inorganic matter, and water) that are easily ruptured and/or may aggregate during sampling. As such, we lack reliable information on parameters such as settling velocities, particularly since floc properties change over tidal (suspension/advection), lunar (spring-neap cycle), and seasonal (storm resuspension and biological production) time scales. Turbulence is an important mediator of floc characteristics; low turbulence promotes collisions and flocculation, while high levels cause shear-induced rupture, literally tearing flocs apart. Because of this, turbulence parameterisation is key to understanding the relationship between turbulence and particle size. The results of an extensive field campaign in the Dee Estuary (N.W. United Kingdom) are presented, investigating the fates of SPM. Using data from a combination of acoustics, optics, moored deployments and CTD stations particle characteristics varied across tidal, spring-neap, and seasonal time-scales. This was due to seasonal changes in both river input and levels of biological activity. During winter, turbulence-mediated flocculation and breakup dominated, with particles coming together under quiescent conditions, and breaking up during high turbulence conditions. By contrast, stronger, more shear-resistant flocs were present during summer with increased yield strength providing

  1. Fishes and fisheries in tropical estuaries: The last 10 years

    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

  2. Distribution of hypoxia and pycnocline off the Changjiang Estuary, China

    Zhu, Jianrong; Zhu, Zhuoyi; Lin, Jun; Wu, Hui; Zhang, Jing

    2016-02-01

    The distributions of hypoxia and the pycnocline off the Changjiang Estuary were investigated by making several field observations from June 2 to 11, from July 18 to 23, from August 20 to 30, from October 3 to 13, 2006, and from August 27 to September 3, 2009. The observations from July 18 to 23, 2006, mainly focused on analyzing the relationship between hypoxia and the extension of the river plume and vertical stratification. In July, the Changjiang diluted water (CDW) was influenced by the easterly typhoon winds, causing it to extend northward rather than northeastward. By using the maximum vertical density gradient as a stratification intensity index, we found that the area of low ( 2.0 kg/m4), which indicated that the summer pycnocline can effectively block vertical DO exchange and maintain hypoxia near the bottom. The observed hypoxic area was 500 km2, which was much smaller than the hypoxic areas observed in previous studies, and occurred because of the enhanced mixing that resulted from Typhoon Bill. During the observation period of August 20-30, 2006, the maximum density gradient was weaker due to distinct low river discharge. No hypoxia was observed in the eastern and southeastern sea off the Changjiang Estuary where hypoxia often occurs. However, hypoxia occurred over a large area of 15,400 km2 in the northern observation domain where hypoxia rarely occurs. During June 2-11 and October 3-13, 2006, the maximum density gradient was weaker, and the area with low DO was smaller than in July 2006. This finding resulted from relatively low river discharge and weaker solar heating. Consequently, no hypoxia occurred in the bottom layer. The area of low DO was similar to that of the maximum vertical density gradient. From August 27 to September 3, 2009, high river discharge and strong solar heating produced a larger and more intense pycnocline. The hypoxic area reached 3735 km2 and was very similar to the area of the pycnocline, which was greater than 3.0 kg/m4

  3. Tide-driven fluid mud transport in the Ems estuary

    Becker, Marius; Maushake, Christian; Winter, Christian

    2014-05-01

    The Ems estuary, located at the border between The Netherlands and Germany, experienced a significant change of the hydrodynamic regime during the past decades, as a result of extensive river engineering. With the net sediment transport now being flood-oriented, suspended sediment concentrations have increased dramatically, inducing siltation and formation of fluid mud layers, which, in turn, influence hydraulic flow properties, such as turbulence and the apparent bed roughness. Here, the process-based understanding of fluid mud is essential to model and predict mud accumulation, not only regarding the anthropogenic impact, but also in view of the expected changes of environmental boundary conditions, i.e., sea level rise. In the recent past, substantial progress has been made concerning the understanding of estuarine circulation and influence of tidal asymmetry on upstream sediment accumulation. While associated sediment transport formulations have been implemented in the framework of numerical modelling systems, in-situ data of fluid mud are scarce. This study presents results on tide-driven fluid mud dynamics, measured during four tidal cycles aside the navigation channel in the Ems estuary. Lutoclines, i.e., strong vertical density gradients, were detected by sediment echo sounder (SES). Acoustic Doppler current profiles (ADCP) of different acoustic frequencies were used to determine hydrodynamic parameters and the vertical distribution of suspended sediment concentrations in the upper part of the water column. These continuous profiling measurements were complemented by CTD, ADV, and OBS casts. SES and ADCP profiles show cycles of fluid mud entrainment during accelerating flow, and subsequent settling, and the reformation of a lutocline during decelerating flow and slack water. Significant differences are revealed between flood and ebb phase. Highest entrainment rates are measured at the beginning of the flood phase, associated with strong current shear and

  4. 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...

  5. 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...

  6. Carbon budgets for three autotrophic Australian estuaries: Implications for global estimates of the coastal air-water CO2 flux

    Maher, D. T.; Eyre, B. D.

    2012-03-01

    Estuaries are `hot spots' in the global carbon cycle, yet data on carbon dynamics, in particular air-sea CO2 fluxes, from autotrophic systems are rare. Estuarine carbon budgets were constructed for three geomorphically distinct warm temperate Australian estuaries over an annual cycle. All three estuaries were net autotrophic, with annual net ecosystem metabolism (NEM) ranging from 8 ± 13.4 molC m-2 yr-1 to 10 ± 14 molC m-2 yr-1. There was a net flux of CO2 from the atmosphere to the estuaries of between 0.4 ± 0.6 molC m-2 yr-1 and 2 ± 0.9 molC m-2 yr-1. Loading of dissolved inorganic carbon (DIC) and dissolved organic carbon (DOC) to the estuaries varied markedly within and between the estuaries, and was directly related to freshwater inflow. While NEM was similar in all three estuaries, the ratio of benthic versus pelagic contributions to NEM differed, with NEM dominated by pelagic production in the river dominated system, benthic production dominating in the intermediate estuary, and equal contributions of benthic and pelagic production in the marine dominated lagoon. All three estuaries exported more organic carbon than was imported, fueled by additional organic carbon supplied by NEM. The estuaries essentially acted as bioreactors, transforming DIC to organic carbon. Burial of organic carbon ranged from 1.2 ± 0.3 molC m-2 yr-1 to 4.4 ± 1.2 molC m-2 yr-1 and represented up to half of NEM. The annual net uptake of atmospheric CO2 in these systems, along with previous estimates of the global estuarine CO2flux being based predominantly on heterotrophic, large river dominated estuarine systems, indicates that the global estimate of the estuarine air-water CO2flux may be over-estimated due to the lack of studies from autotrophic marine dominated estuaries.

  7. Bathymetry of the southwest flank of Mauna Loa Volcano, Hawaii

    Chadwick, William W.; Moore, James G.; Fox, Christopher G.

    1994-01-01

    Much of the seafloor topography in the map area is on the southwest submarine flank of the currently active Mauna Loa Volcano. The benches and blocky hills shown on the map were shaped by giant landslides that resulted from instability of the rapidly growing volcano. These landslides were imagined during a 1986 to 1991 swath sonar program of the United States Hawaiian Exclusive Economic Zone, a cooperative venture by the U.S. Geological Survey and the British Institute of Oceanographic Sciences (Lipman and others, 1988; Moore and others, 1989). Dana Seamount (and probably also the neighboring Day Seamount) are apparently Cretaceous in age, based on paleomagnetic studies, and predate the growth of the Hawaiian Ridge volcanoes (Sager and Pringle, 1990).

  8. Wolf predation in the Burwash caribou herd, southwest Yukon

    David A. Gauthier

    1986-06-01

    Full Text Available The role of wolf predation as a proximate mortality factor influencing caribou herd growth was assessed in the Burwash herd (400 animals in the southwest Yukon between 1980 - 1982. Ten to 14 wolves in two packs preyed primarily on caribou (Rangifer tarandus caribou and moose (Alces alces with disproportionate consumption of caribou (relative to available biomass in the rut and winter periods. Wolf predation was responsible for 72% of total annual mortality in 1980 - 1981 and 46% in 1981 - 1982. Losses due to human harvest varied between 7 to 13%. Additional limited data on climatic factors and winter forage indicated forage-climate were not major proximate mortality factors in 1980 - 1981, but that early-calving climate may have been a factor in increased calf mortality in 1982.

  9. Reservoir characterization of the Smackover Formation in southwest Alabama

    Kopaska-Merkel, D.C.; Hall, D.R.; Mann, S.D.; Tew, B.H.

    1993-02-01

    The Upper Jurassic Smackover Formation is found in an arcuate belt in the subsurface from south Texas to panhandle Florida. The Smackover is the most prolific hydrocarbon-producing formation in Alabama and is an important hydrocarbon reservoir from Florida to Texas. In this report Smackover hydrocarbon reservoirs in southwest Alabama are described. Also, the nine enhanced- and improved-recovery projects that have been undertaken in the Smackover of Alabama are evaluated. The report concludes with recommendations about potential future enhanced- and improved-recovery projects in Smackover reservoirs in Alabama and an estimate of the potential volume of liquid hydrocarbons recoverable by enhanced- and improved-recovery methods from the Smackover of Alabama.

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

    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

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

    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

  12. Uncertainty quantification of US Southwest climate from IPCC projections.

    Boslough, Mark Bruce Elrick

    2011-01-01

    The Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4) made extensive use of coordinated simulations by 18 international modeling groups using a variety of coupled general circulation models (GCMs) with different numerics, algorithms, resolutions, physics models, and parameterizations. These simulations span the 20th century and provide forecasts for various carbon emissions scenarios in the 21st century. All the output from this panoply of models is made available to researchers on an archive maintained by the Program for Climate Model Diagnosis and Intercomparison (PCMDI) at LLNL. I have downloaded this data and completed the first steps toward a statistical analysis of these ensembles for the US Southwest. This constitutes the final report for a late start LDRD project. Complete analysis will be the subject of a forthcoming report.

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

    Andrew C. Coward

    2011-11-01

    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 hydrographic, 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.

  14. Marine mammal strandings in the New Caledonia region, Southwest Pacific.

    Borsa, Philippe

    2006-04-01

    Four hundred twenty three marine mammals, in 72 stranding events, were recorded between 1877 and 2005 in New Caledonia, the Loyalty Islands, and Vanuatu in the southwest Pacific. Sixteen species were represented in this count, including: minke whale, Balaenoptera acutorostrata (1 single stranding), sei whale, B. borealis (1 single stranding), blue whale, B. musculus (1 single stranding), humpback whale, Megaptera novaeangliae (2 single strandings), giant sperm whale, Physeter macrocephalus (18 single strandings, 2 pair strandings), pygmy sperm whale, Kogia breviceps (5 single strandings), dwarf sperm whale, K. sima (2 single strandings, 1 triple stranding), Blainville's beaked whale, Mesoplodon densirostris (2 single strandings), short-finned pilot whale, Globicephala macrorhynchus (4 strandings, 56 individuals), melon-headed whale, Peponocephala electra (1 single stranding and 2 mass strandings totalling 231 individuals), common dolphin, Delphinus delphis (1 single stranding), spinner dolphin, Stenella longirostris (1 pair stranding and 2 mass strandings of groups of approximately 30 individuals each), Indian Ocean bottlenose dolphin, Tursiops aduncus (2 single strandings), dugong, Dugong dugon (14 single strandings), and New Zealand fur seal, Arctocephalus forsteri (3 single strandings). A stranded rorqual identified as an Antarctic minke whale (B. bonaerensis), with coloration patterns that did not match known descriptions, was also reported. Sei whale was recorded for the first time in the tropical Southwest Pacific region and Antarctic minke whale, melon-headed whale, and Indian Ocean bottlenose dolphin were recorded for the first time in New Caledonia. Strandings of sperm whales were most frequent in the spring, but also occurred in autumn months, suggesting a seasonal pattern of occurrence possibly related to seasonal migration. One stranded humpback whale bore the scars of a killer whale's attack and one dugong was injured by a shark. Scars left by

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

    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 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

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

    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.

  17. Chondrichthyan egg cases from the south-west Atlantic Ocean.

    Mabragaña, E; Figueroa, D E; Scenna, L B; Díaz de Astarloa, J M; Colonello, J H; Delpiani, G

    2011-11-01

    Egg cases of 21 oviparous chondrichthyan species from the south-west Atlantic Ocean are described and compared. The catshark Schroederichthys bivius has a cigar-shaped egg case with curled tendrils only at the posterior end. Egg cases of the elephant fish Callorhinchus callorynchus are spindle-shaped with anterior and posterior tubular extensions and lateral flanges. The skate Amblyraja doellojuradoi presents medium-sized egg cases (71 mm in length) with a lateral keel extending to the first portion of the horns. The endemic skate species of the genus Atlantoraja have medium to large egg cases (69-104 mm in length) and present relatively large posterior horns. Egg cases of the genus Bathyraja have a medium size, 75-98 mm in length, and are characterized by a very similar morphology, a relatively smooth to rough surface case and posterior horns strongly curved inwards. Egg cases of the genera Dipturus and Zearaja are very large, 115-230 mm in length, and have a well-developed posterior apron. Despite the problematical identification of skates at species level, the egg capsules of the endemic genus Psammobatis are easily diagnosed; the capsules are small (25-53 mm in length), those of Psammobatis rutrum being the smallest known to date in the world. Egg cases of Rioraja agassizi have a medium size, 61-68 mm in length, relatively straight sides, a smooth surface and silky attachment fibres placed in the lateral keel next to each horn. Those of the genus Sympterygia are small to medium sized, 51-86 mm in length, and display the thickest lateral keel and the longest posterior horns among the skates of the world. Egg cases can be a useful tool for identifying species and egg-laying areas; therefore, a provisional key for the south-west Atlantic Ocean chondrichthyan capsules is presented. PMID:22026605

  18. Tidal and spatial variability of nitrous oxide (N2O) in Sado estuary (Portugal)

    Gonçalves, Célia; Brogueira, Maria José; Nogueira, Marta

    2015-12-01

    The estimate of the nitrous oxide (N2O) fluxes is fundamental to assess its impact on global warming. The tidal and spatial variability of N2O and the air-sea fluxes in the Sado estuary in July/August 2007 are examined. Measurements of N2O and other relevant environmental parameters (temperature, salinity, dissolved oxygen and dissolved inorganic nitrogen - nitrate plus nitrite and ammonium) were recorded during two diurnal tidal cycles performed in the Bay and Marateca region and along the estuary during ebb, at spring tide. N2O presented tidal and spatial variability and varied spatially from 5.0 nmol L-1 in Marateca region to 12.5 nmol L-1 in Sado river input. Although the Sado river may constitute a considerable N2O source to the estuary, the respective chemical signal discharge was rapidly lost in the main body of the estuary due to the low river flow during the sampling period. N2O varied with tide similarly between 5.2 nmol L-1 (Marateca) and 10.0 nmol L-1 (Sado Bay), with the maximum value reached two hours after flooding period. The influence of N2O enriched upwelled seawater (˜10.0 nmol L-1) was well visible in the estuary mouth and apparently represented an important contribution of N2O in the main body of Sado estuary. Despite the high water column oxygen saturation in most of Sado estuary, nitrification did not seem a relevant process for N2O production, probably as the concentration of the substrate, NH4+, was not adequate for this process to occur. Most of the estuary functioned as a N2O source, and only Marateca zone has acted as N2O sink. The N2O emission from Sado estuary was estimated to be 3.7 Mg N-N2O yr-1 (FC96) (4.4 Mg N-N2O yr-1, FRC01). These results have implications for future sampling and scaling strategies for estimating greenhouse gases (GHGs) fluxes in tidal ecosystems.

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

    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

  20. Measuring hydrodynamics and sediment transport processes in the Dee Estuary

    Bolaños, R.; Souza, A.

    2010-06-01

    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, bodc.ac.uk/" target="_blank">http://www.bodc.ac.uk/) which is the formal British organization for looking after and distributing data concerning the marine environment.

  1. Measuring hydrodynamics and sediment transport processes in the Dee Estuary

    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.

  2. Measuring hydrodynamics and sediment transport processes in the Dee estuary

    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.

  3. Environmental flow assessments in estuaries related to preference of phytoplankton

    Yang, Z. F.; Sun, T.; Zhao, R.

    2014-05-01

    An approach to assess estuarine environmental flow based on phytoplankton preference, including the complex relationships between hydrological modifications and ecosystem biomass, was developed in this study. We initially established a relationship between biomass requirements for primary and higher nutritional level organisms based on the ecosystem nutritional energy flow principles. Subsequently, diagnostic pigments were employed to represent phytoplankton community biomass, which indicated competition between two groups of phytoplankton in the biochemistry process. Considering empirical relationships between diagnostic pigments and critical environmental factors, biomass responses to river discharge were established by simulating distributions of critical environmental factors under action of river discharges and tide currents. Consequently, environmental flows were recommended for different fish biomass requirements. We used the Yellow River estuary as a case study; and May and June were identified as critical months for maintaining environmental flow. Temporal variation in natural river flow dynamics, which was used as a proxy for environmental flow, should be carefully examined in artificial hydrological regulation strategies, particularly during high-amplitude flood pulses, which might result in negative effects on phytoplankton groups, and subsequently higher aquatic species biomass.

  4. Wind impact on pollutant transport in a shallow estuary

    XU Hongzhou; LIN Jing; SHEN Jian; WANG Dongxiao

    2008-01-01

    A three-dimensional numerical model, EFDC (environmental fluid dynamics code) is applied to the Pamlico River Estuary (PRE) in eastern North Carolina of the United States to examine the wind impact on pollutant age distributions and residence time. A series of model experiments representing base case, remote-wind-induced water level set-up and local winds cases are conducted. Model results indicate that the pollutant mean age and the system residence time are functions of gravitational circula-tion in the PRE. The system responses to remote-wind-induced water level set-up are different in different portions of the PRE. Under such condition, dissolved substances in the upstream portion of the PRE have a younger age and shorter residence time (compared with the base case), by contrast, they have a older age and longer residence time in the downstream portion of the PRE. Upriver and downriver local winds appear to have opposite impacts on pollutant age distributions. The substances are re-tained much longer within the PRE under upriver wind than those under downriver wind. The model results also suggest that across -river winds may lead to longer residence time through enhanced turbulence mixing, which slows down the gravitational circulation in the PRE.

  5. An overview of tritium behaviour in the Severn Estuary (UK)

    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 μSv 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)

  6. Radioactivity and United Kingdom estuaries: an overview identifying research priorities

    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.)

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

    U.S. Bonneville Power Administration

    2008-08-01

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

  8. Using attached macroalgae to assess ecological status of British estuaries for the European Water Framework Directive.

    Wilkinson, Martin; Wood, Paul; Wells, Emma; Scanlan, Clare

    2007-01-01

    The EC Water Framework Directive requires that ecological quality be assessed in transitional waters using the abundance and species composition of macroalgae. In estuaries, which form the majority of transitional waters, species composition is not a suitable measure. This arises from two features: (i) there is a continuous, natural change in species composition along the gradient of estuarine conditions which makes it difficult to know where within an estuary the species composition should be assessed, (ii) the inner estuarine macroalgal community of mat-forming species is very tolerant to both natural and anthropogenic stress and species poor which makes it insensitive to environmental variations in terms of species composition. An alternative feature is proposed based on the extent of upstream penetration of perennial fucoid algae. This proposal is founded on a series of case studies of the changes in fucoid limits, within a number of estuaries in the British Isles, consequent upon changes in pollution status over the last three decades. This also has to take into account variations of fucoid penetration owing to natural factors such as range of salinity variation and turbidity. The abundance criterion is taken to mean the absence of macroalgal blooms or "green tides", because general abundance of species is hard to quantify meaningfully in the upper estuarine mat-forming species and in the lower estuary is subject to great variation owing to the physical variability of estuary types. PMID:17084419

  9. Contamination by Organochlorine Pesticides in the Estuaries of Southeast China* 06 A

    2002-01-01

    Persistent organic pollutants(POPs) such as organochlorine pesticides are of global concern due to their widespread occurrence and persistence. This paper reports recent research studying the distribution and fate of organochlorine pesticides in the Jiulong River, the Minjiang River and the Pearl River estuaries in Southeast China. Eighteen organochlorine pesticides were extracted from water, pore water and sediment samples, followed by analysis by GC-ECD. The results showed that the contamination levels were similar in these three estuaries.The levels of the total organochlorine pesticides in porewater were significantly higher than those in surface water, due to the high affinity of these hydrophobic compounds for sediment phase. Among the hexachlorocyclohexane (HCH) compounds, β-HCH was found to be the most important isomer. The analysis of 1, 1,1-trichloro-2,2-bis-chlorophenyl-ethane(DDT) and its metabolites showed that 1, 1-dichloro-2[o-chlorophenyl]-2[p-chlorophenyl]-ethylene (DDE) was dominant in the group.Koywords Organochlorine insecticides, DDT, Lindane, Jiulong River Estuary, Minjiang River Estuary, Pearl River Estuary, Water, Sediment

  10. Land claim and loss of tidal flats in the Yangtze Estuary

    Chen, Ying; Dong, Jinwei; Xiao, Xiangming; Zhang, Min; Tian, Bo; Zhou, Yunxuan; Li, Bo; Ma, Zhijun

    2016-04-01

    Tidal flats play a critical role in supporting biodiversity and in providing ecosystem services but are rapidly disappearing because of human activities. The Yangtze Estuary is one of the world’s largest alluvial estuaries and is adjacent to the most developed economic zone in China. Using the Yangtze Estuary as a study region, we developed an automatic algorithm to estimate tidal flat areas based on the Land Surface Water Index and the Normalized Difference Vegetation Index. The total area of tidal flats in the Yangtze Estuary has decreased by 36% over the past three decades, including a 38% reduction in saltmarshes and a 31% reduction in barren mudflats. Meanwhile, land claim has accumulated to 1077 km2, a value that exceeds the area of the remaining tidal flats. We divided the Yangtze Estuary into Shanghai and Jiangsu areas, which differ in riverine sediment supply and tidal flat management patterns. Although land claim has accelerated in both areas, the decline in tidal flat area has been much greater in Jiangsu than in Shanghai because of abundant supplies of sediment and artificial siltation in the latter area. The results highlight the need for better coastal planning and management based on tidal flat dynamics.

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

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

    2014-07-01

    A study was conducted to understand the intra- and inter-seasonal variability of dissolved oxygen and nutrients in a tropical monsoon estuary (Zuari in Goa, India). We adopted a dual sampling approach with (a) daily or alternate day sampling at a fixed location in the mid-estuarine zone and (b) longitudinal transect sampling from freshwater end to mouth during spring and neap tides of each month for about a year. Multivariate statistical analyses of oxygen and nutrients were carried out to evaluate the hypotheses: (i) biogeochemical processes chiefly regulate their variability and (ii) anthropogenic inputs lead to material accumulation in the estuary. Multivariate statistical analyses helped identify the controlling factors of the oxygen and nutrient variability. Our results significantly revealed (i) physical forcings (freshwater discharge and tidal circulation, these also facilitate sedimentary releases) are more important than biogeochemical processes in determining oxygen and nutrient variability in the water column and (ii) the monsoon driven regular annual flushing makes the system resilient to human interference as the Zuari estuary returns to normalcy by postmonsoon every year. Our study identified the significance of subsurface 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 in time and space in the estuary.

  12. Fingerprinting of bed sediment in the Tay Estuary, Scotland: an environmental magnetism approach

    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

  13. Freshwater scarcity effects on the aquatic macrofauna of a European Mediterranean-climate estuary.

    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

  14. Spatial-temporal distribution of fish density in the Oujiang estuary during summer and autumn

    XU Zhao-Li

    2008-12-01

    Full Text Available The spatial-temporal distribution of fish in the Oujiang estuary and the impact factors such as dominant species, topography and geography, as well as hydrological factors on the distribution were investigated during two surveys in June and September 2007. Results showed that weight density (total fish weight in a given water area was 150.54 (kg/km2 and individual density (total fish number in a given water area was 29.11 (103 ind./ km2 in June, and 271.53 (kg/km2 and 14.99 (103 ind./ km2 in September, respectively. In another word, the biomasses in the estuary were 67923 kg and 122193 kg in June and September, respectively. The dominant fish species was Argyrosomus argentatus in June, and was replaced by Harpodon nehereus in September. Distribution pattern of fish weight and number was the same in the estuary, which was that both fish weight and number were higher in the east part than in the west part. Fish distribution was positively related to water depth, and surface water temperature significantly affected the seasonal distribution of fish in the estuary. Mixture of Taiwan current and Oujiang discharge forms an ideal hydrological environment in the estuary for fish. [Acta Zoologica Sinica 54(6):981– 987, 2008].

  15. Facilitation of the Estuary/Ocean Subgroup for Research, Monitoring, and Evaluation, FY07 Annual Report

    Johnson, Gary E.; Diefenderfer, Heida L.

    2007-10-10

    This annual report is a deliverable for fiscal year 2007 (FY07) for Project 2002-077-00, Facilitation of the Estuary/Ocean Subgroup (EOS). The EOS is part of the research, monitoring, and evaluation (RME) effort the Action Agencies (Bonneville Power Administration, U.S. Army Corps of Engineers, U.S. Bureau of Reclamation) developed in response to responsibilities arising from the Endangered Species Act as a result of operation of the Federal Columbia River Power System (FCRPS). The goal of the EOS project is to facilitate activities of the estuary/ocean RME subgroup as it coordinates design and implementation of federal RME in the lower Columbia River and estuary. In FY07, EOS project accomplishments included 1) subgroup meetings; 2) participation in the estuary work group of the Pacific Northwest Aquatic Monitoring Partnership; 3) project management via the project tracking system, PISCES; 4) quarterly project status reports; and 5) a major revision to the Estuary RME Plan (new version September 2007) based on comments by EOS members and invited reviewers.

  16. Facilitation of the Estuary/Ocean Subgroup for Research, Monitoring and Evaluation - FY07 Annual Report.

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

    2007-10-10

    This annual report is a deliverable for fiscal year 2007 (FY07) for Project 2002-077-00, Facilitation of the Estuary/Ocean Subgroup (EOS). The EOS is part of the research, monitoring, and evaluation (RME) effort of the Action Agencies (Bonneville Power Administration, U.S. Army Corps of Engineers, U.S. Bureau of Reclamation) developed in response to responsibilities arising from the Endangered Species Act as a result of operation of the Federal Columbia River Power System (FCRPS). The goal of the EOS project is to facilitate activities of the estuary/ocean RME subgroup as it coordinates design and implementation of federal RME in the lower Columbia River and estuary. In FY07, EOS project accomplishments included (1) subgroup meetings; (2) participation in the estuary work group of the Pacific Northwest Aquatic Monitoring Partnership; (3) project management via the project tracking system, PISCES; (4) quarterly project status reports; and (5) a major revision to the Estuary RME Plan (new version September 2007) based on comments by EOS members and invited reviewers.

  17. Phytoplankton Assemblage Structure Shaped by Key Environmental Variables in the Pearl River Estuary, South China

    ZHANG Xia; ZHANG Jingping; HUANG Xiaoping; HUANG Liangmin

    2014-01-01

    Spatial distribution and temporal dynamics of phytoplankton community and their relationships with environmental factors were studied in the Pearl River Estuary (PRE), South China, in three seasons. Salinity was considered as the key environ-mental variable controlling horizontal distributions of phytoplankton community composition. A transition from dominance of freshwater diatoms (Aulacoseira granulata and A. granulata v. angustissima) to estuarine species (Skeletonema costatum and Pseu-donitzschia delicatissima) was observed in the high flow season (summer) along the estuary gradient;in the low flow season (spring), the inner estuary was relatively homogeneous and some typical estuarine species could be found near the river mouth. In the normal flow season (autumn), a potentially toxic bluegreen species, Microcystis spp. was predominant in the middle reaches of the estuary, which should be seeded from upstream and transported downstream by river discharges. Phytoplankton abundance was negatively correlated with suspended solid content and nutrient concentration in the PRE, suggesting that turbidity and nutrient availability were the crucial factors regulating the algal biomass. Phytoplankton abundance in the outer estuary was enhanced by increasing irradiance and continued to be enhanced until phosphorus-limitation.

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

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

    2014-01-01

    Coupled nitrification–denitrification plays a critical role in the removal of excess nitrogen, which is chiefly caused by humans, to mitigate estuary and coastal eutrophication. Despite its obvious importance, limited information about the relationships between nitrifying and denitrifying microbial communities in estuaries, and their controlling factors have been documented. We investigated the nitrifying and denitrifying microbial communities in the estuary of turbid subtro...

  19. Zooplankton structure and dynamics in two estuaries from the Atlantic coast in relation to multi-stressors exposure

    Vieira, L. R.; Guilhermino, L.; Morgado, F.

    2015-12-01

    The aim of this research was to investigate the response of pelagic zooplankton to different levels of abiotic multi-stressors in the North Atlantic coast, taking advantage of the comparison of the communities of two adjacent estuaries with different levels of historical pollution (estuaries of Minho and Lima Rivers). The zooplankton community structure, composition and temporal variation were comparatively investigated for 15 months, using different net meshes. Several abiotic factors were measured in situ and water samples were simultaneously collected for determination of nutrients and chlorophyll a. The overall results revealed a diverse community represented by species that have been found in subtropical and temperate zones. Although the highest diversity was observed in the Lima estuary, supported by higher contributions of marine taxa, the total zooplankton biomass was found to be significantly higher in the Minho estuary. The salinity gradient differences between estuaries, associated to significant differences in water nutrients levels, were found to be the main forcing factors affecting micro and mesozooplankton. Considering the importance of the impacts resulting from abiotic variation on the basis of aquatic food webs, the present investigation represented a case-study, based in two contrasting estuaries, one strongly influenced by freshwater discharges (Minho estuary) and the other with higher salinity levels (Lima estuary), contributing to a better understanding of the effects of multi-stressors on pelagic zooplankton communities, providing useful information for studies related with climate change impacts, biogeography, conservation and providing data contributing to the improvement of pelagic fisheries management models.

  20. A stratification prediction diagram from characteristics of geometry, tides and runoff for estuaries with a prominent channel

    Vijith, V.; Shetye, S.R.

    -stratified to partially-mixed to well-mixed due to change in runoff from wet to dry season. Using data from 16 estuaries around the world, we show that the diagram can be used to distinguish characteristics of stratification and of forcing functions between estuaries....