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Sample records for gironde estuary southwest

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

    Science.gov (United States)

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

    2015-06-01

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

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

    OpenAIRE

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

    1994-01-01

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

  3. Spatial distribution and dynamics of microphytobenthos biomass in the Gironde estuary (France)

    OpenAIRE

    Santos, Pjp; Castel, J.; Souzasantos, Lp

    1997-01-01

    The spatial variation of microphytobenthos was investigated with reference to both the estuarine gradient and the intertidal levels of the Gironde estuary, France. Four transects, each with three stations, were surveyed in two different seasons (April and October) during two consecutive years. In addition, the seasonality of microphytobenthic pigment concentration and its relationship to environmental factors were examined by means of weekly sampling at an intertidal mudflat located in the ol...

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

    Energy Technology Data Exchange (ETDEWEB)

    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 extracted by means of concentrated HNO{sub 3}, estuarine freshwaters and waters of two different salinities (S=15 and S=31). Analysis of trace elements was carried out by means of quadrupole inductively coupled plasma-mass spectrometry. Furthermore, single particles from road sediments were characterised with scanning electron microscopy (SEM). Results: SEM analysis clearly showed that some particles contained fairly high concentrations of potentially toxic trace elements. Extractions of materials investigated by varying acidities and salinities documented that the potentially bioavailable fractions extracted by concentrated HNO{sub 3} may cover wide concentration ranges. Natural estuarine waters of various salinities (S=0.5; S=15; S=31) extracted high proportions of Co, Ni, Cu, Zn and Cd from urban particles, especially for high-salinity water (S=31). Extractions with freshwater revealed the lowest concentrations of desorbed trace elements. Particulate Mo, Pb and V showed similar or lower mobility in saline water compared with freshwater, depending on the sample type. Discussion: Trace element mobility in estuarine waters varied according to the type of urban particles and depended on salinity for Co, Ni, Cu, Zn and Cd. This is of high importance for towns located directly at the coast or for cities like Bordeaux, where water courses crossing the agglomerations are connected to saline water masses. Since trace elements desorbed from particles in saline waters may become highly bioavailable, they bear a potential risk for organisms. Comprehensive studies on the behaviour of urban particles in estuarine waters and the related potential environmental impact are still missing. Conclusions: Saline waters mobilise relatively high amounts of Co, Ni, Cu, Zn and Cd from urban particles suggesting considerable metal fluxes from riverine urban systems into coastal waters. Although estimates of trace metal inputs by urban bulk deposition (urban dust) and other types of urban particles are preliminary for Bordeaux and may bear important uncertainties due to several assumptions

  5. A 9-year continuous monitoring of salinity in the Gironde estuary (S-W France) reveals marked inter-annual variability in marine intrusion

    Science.gov (United States)

    Schmidt, Sabine; Sottolichio, Aldo

    2013-04-01

    Estuaries form a transition zone in which rivers and oceans meet, including both fresh and salt waters. Thus conditions in estuary are more variable than those in either rivers or marine environments. In particular salinity presents a large temporal and lateral variations, depending of the degree of water mixing. The limit of salinity intrusion along an estuary is determined by the balance between the landward transport of salt by tidal processes and its seaward return by freshwater discharges. The major factor that affects the limit of saline intrusion along an estuary is freshwater inflow. In a context of global change, salinity intrusion in estuaries is expected to increase due to the cumulative effect of decrease in freshwater flows (changes in rain rate, decrease of riverine discharge due to upstream land use) and to sea level rives. At present, it is still difficult to establish changes in marine intrusion in estuaries due to the limited available data set. With its 625 km2, the Gironde estuary (S-W France) is one of the largest European estuaries. Since 2004, a real-time continuous system (MAGEST network) records four selected parameters (salinity, turbidity, dissolved oxygen) to establish a reference database of water-quality of this fluvio-estuarine system to address current and future water-quality issues. Here we present in details the 9-year time series of salinity in the Gironde estuary, recorded at four stations representative of the central and up estuary. Not surprisingly there are large difference among the four instrumented stations depending on their localization. But the time-series had allowed to highlight marked inter-annual variability in relation with the local hydrology. This example clearly illustrates the interest of long-term time series to detect potential changes in salinity, related to global changes, from inter-annual variability.

  6. Successful colonization of the calanoid copepod Acartia tonsa in the oligo-mesohaline area of the Gironde estuary (SW France) Natural or anthropogenic forcing?

    Science.gov (United States)

    David, Valérie; Sautour, Benoît; Chardy, Pierre

    2007-02-01

    The copepod Acartia tonsa appeared in Europe in the first half of the 20th century and colonized progressively European seas and estuaries, possibly transferred from North Atlantic Coast of America. It had been reported in the polyhaline area of the Gironde estuary for a long time but was first recorded in the oligo-mesohaline area in 1983. Its abundance has been increasing significantly. High abundances of A. tonsa were reported since 1999, supplanting the abundances of its autochthonous congeneric species, Acartia bifilosa. This colonization was characterized by analyzing the mean seasonal variability: (1) for three 5-year periods corresponding to three different steps of A. tonsa appearance (1978-1982, A. tonsa was absent; 1988-1992, low abundances of the species; and 1999-2003, high abundances of A. tonsa) in the oligo-mesohaline area and (2) for three stations distributed along the salinity gradient during the recent period. The aim of this work was to define if this colonization was due to natural or anthropogenic forcing and to evaluate its possible impact on autochthonous zooplanktonic community. Both natural and anthropogenic forcings seem to explain the colonization of Acartia tonsa in the oligo-mesohaline area of the Gironde estuary. First records (1983-1988) could be due to marine water inputs caused by high values of the North Atlantic Oscillation index. The global warming which caused the increase of the summer warm period, the marinisation of the system and the local decrease of the turbidity should have been the key factors favoring the establishment of the species. Anthropogenic forcings as the establishment of the nuclear power plant which locally causes warmer conditions are also important factors explaining the differences of seasonal cycle observed between oligo-mesohaline area and other stations: the seasonal pattern of A. tonsa in the oligo-mesohaline area was indeed characterized by an autumnal peak of abundances which has been observed in other stations and in many North European estuaries, and by a second spring peak that had only been observed in Southern estuaries. The introduction of Acartia tonsa in the Gironde estuary significantly changed the seasonal pattern of autochthonous copepods, by limiting their seasonal abundances without affecting their long-term population stability. Finally, the successful colonization of A. tonsa had led to the spread of the seasonal zooplanktonic production which could have had an impact on fish and shrimp productions.

  7. Double radio-tracer tagging of mud in the Gironde: an experimental study of the behaviour of a metallic pollutant in an estuary

    International Nuclear Information System (INIS)

    In order to understand the behaviour of metals accidentally introduced into an estuarine system, an experiment using radioactive tracers was conducted in the Gironde estuary. Based on the preliminary laboratory studies on the reactivity of radioisotopes 65Zn and 175+181Hf with different physicochemical agents, they were proved to be suitable for the experiment designed. A quantity of sediment contaminated by these two isotopes was introduced in the upstream part of the Gironde. During transport downstream, it was observed that the Zn/Hf couple on the sediment decreased from an initial ratio of 0.7 to 0.07-0.05 in the fluid mud lenses and in the bottom sediment of the lower estuary at the end of the experiment (3 months). It was lower than 0.2 in the suspended sediments. This is considered to indicate that a part of the zinc is dissociated from the hafnium and released from its particulate support; this signifies a solubilization of the zinc. These experimental data give a new insight into the problem concerning the decrease of stable zinc associated with suspended sediment at the fresh water/salt water interface

  8. Recording and chronology of a cadmium contamination by 137Cs in the Gironde estuary (SW France)

    International Nuclear Information System (INIS)

    The detailed analysis of the Cd distribution coupled with 137Cs measurements have been conducted in a core recovered from a flood-tidal dock of the Bordeaux harbour. They enabled reconstruction and dating of the record of industrial contamination which has developed over recent decades. The cadmium distribution accurately reflects the different stages of activity of a foundry at Vivies-Decazeville. The 137Cs curve likely records the fallout of the nuclear tests performed between 1950 and 1970, and probably also the Chernobyl fallout, that has never been mentioned in the Southwest of France until now. (authors)

  9. Seaward pinching out and internal stratigraphy of the Gironde incised valley on the shelf (Bay of Biscay)

    OpenAIRE

    Lericolais, Gilles; Berne, Serge; Fenies, Hugues

    2001-01-01

    An incised paleovalley offshore the estuary mouth of the Gironde River (Southwest France) was evidenced recently (Comptes Rendus de 1'Academie des Sciences de Paris 326 (1998) 701). Nevertheless its seaward extension to the shelf break was still unknown. New high-resolution geophysical data were acquired on the continental shelf in order to follow the incision until the shelf break. After processing the seismic lines, the shape of the valley was identified and the valley-fill in terms of sequ...

  10. Seasonal succession of estuarine fish, shrimps, macrozoobenthos and plankton: Physico-chemical and trophic influence. The Gironde estuary as a case study

    Science.gov (United States)

    Selleslagh, Jonathan; Lobry, Jérémy; N'Zigou, Aimé Roger; Bachelet, Guy; Blanchet, Hugues; Chaalali, Aurélie; Sautour, Benoît; Boët, Philippe

    2012-10-01

    Characterization of the structure and seasonal variability of biotic communities is essential for a better understanding of estuarine ecosystem functioning and in order to manage these highly fluctuating and naturally stressed systems. Numerous studies have investigated the role of environmental factors in controlling temporal variations in biotic communities. However, most have concluded that the explanatory power of physico-chemical variables was significant but not sufficient to explain ecological dynamics. The present study aimed to propose the importance of trophic interactions as an additional structuring factor of species seasonal variability by examining simultaneous dynamics of all estuarine biotic communities, using the oligo-mesohaline area of the Gironde estuary (SW France) as a case study. Data on the main biological groups (fish, shrimps, macrozoobenthos and plankton) sampled during a five-year period (2004-2008) at monthly intervals using a well standardized protocol, as well as data on environmental variables, were compiled here for the first time. According to species composition, the Gironde estuary is used as a nursery, feeding, resident and migratory habitat. For almost all species, strong seasonal fluctuations occurred with a succession of species, indicating an optimization of the use of the available resources over a typical year by estuarine biological communities. Multivariate analyses discriminated four seasonal groups of species with two distinctive ecological seasons. A clear shift in July indicated a biomass transfer from a "planktonic phase" to a "bentho-demersal phase", corresponding to spring and summer-autumn periods, respectively. With regard to the temporal fluctuations of dominant species of all biological groups, this study highlighted the possible influence of trophic relationships, predation in particular, on seasonal variations in species abundance, in addition to the physico-chemical influence. This study enabled us to collate important seasonal data and to discuss their integration into seasonal models of estuarine functioning and/or specific prey-predator models. In a global change context, prey abundance variations could generate changes in the temporal dynamics of their predators (and conversely), and potentially in the functioning of the whole estuarine system.

  11. 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)

    International Nuclear Information System (INIS)

    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 ?g 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 values attributed to metal recycling. In contrast, dissolved Cu concentrations (1.08-6.08 ?g l-1) were mostly higher than typical estuarine values, probably due to recycled Cu complexation by dissolved organic matter. Growth, bioaccumulation rates and kinetics in the whole soft body of the bivalves were analyzed every 40 days. Although Cd bioaccumulation of oysters was lower in the basin than in the estuary during the same period (27,000 ng g-1, dry weight and 40,000 ng g-1, respectively) these values are largely above the new human consumption safety level (5000 ng g-1, dw; European Community, 2002). For cockles and clams, Cd bioaccumulation was lower, reaching 1400 ng g-1 and 950 ng g-1, respectively. Similar results were obtained for Zn and Cu suggesting physiological differences between the species and/or differences in the exposure of the organisms due to physico-chemical conditions and metal distribution between dissolved and particulate phases. In contrast, Hg bioaccumulation was highest for cockles reaching bioconcentration factors of ?200,000, which even exceeded that of Cd in oysters (50,000) for the same exposition period. Nevertheless, Hg concentrations remained relatively low in the three bivalve species

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

    Digital Repository Service at National Institute of Oceanography (India)

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

    Water quality in the Cochin Estuary, southwest coast of India during the tsunami attack was assessed and compared with the pre and post tsunami characteristics. From the results obtained, it is evident that a drastic change in hydrography has been...

  13. Utilisation de techniques numérique et statistique pour décrire la circulation sédimentaire de l'embouchure de la Gironde.

    Science.gov (United States)

    Mallet, Cyril; Howa, Hélène; Garlan, Thierry; Sottolichio, Aldo; Le Hir, Pierre; Michel, Denis

    2000-10-01

    Sediment distribution is well defined in the mouth of the Gironde estuary but the sediment dynamics is still poorly understood. The aim of this work is to analyse residual circulation of non-cohesive sediment due to the action of the main hydrodynamic factor: tidal currents. A depth-averaged numerical model emphasises the residual circulation of the Gironde estuary, which is characterised by residual tidal gyres. The comparison between sediment transport calculated from the numerical model and from a statistical analysis of the sedimentary distribution leads to the definition of a simple scheme of non-cohesive sediment circulation in the Gironde estuary's mouth.

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

    Science.gov (United States)

    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 relationship between depth at the mouth and mean annual runoff. To our knowledge, the measurements and results presented here for the estuaries of southwest England are, in many cases, the first that quantify their important in-water physical characteristics and behaviour. Apart from presenting new information, the synthesis has some important implications for estuarine management, and may aid the straightforward estimation of some key physical variables for these systems.

  15. Small-scale variability of zooplankton pyruvate kinase activity in the Gironde Estuary plume (Atlantic French Coast): A case study under unusually low freshwater discharge

    Science.gov (United States)

    Bergeron, Jean-Pierre

    2006-09-01

    Pyruvate kinase (PK) activity measurements are used to assess the role of carbohydrates in global feeding of mesozooplankton communities inhabiting an estuary plume. As a consequence of a remarkably low freshwater discharge rate, the sea surface layers of the area under estuarine influence showed a very moderate salinity fall and a nearly total depletion in nitrates, whereas higher levels of these nutrients were found in deeper, more saline, layers. Small-scale PK activity variations in mesozooplankton appear to be closely correlated to nitrate integration values within the water column. The results were analysed in comparison with literature reports. The study produced a coherent overall interpretation, which strongly supports the reliability of this new biochemical tool in detecting assimilation of trace carbohydrates in the diet of mesozooplankton.

  16. Selenium in sediments and biota from estuaries of southwest England.

    Science.gov (United States)

    Turner, Andrew

    2013-08-15

    Selenium concentrations have been measured in sediment, fucoid macroalgae and macroinvertebrates from four estuaries of SW England (Yealm, Plym, Looe, Fal). Sediment concentrations ranged from about 0.4 ?g g(-1) in the Yealm to 1.49 ?g g(-1) at one site in the Plym. Concentrations in Fucus vesiculosus (0.05-0.31 ?g g(-1)) and F. ceranoides (0.05-0.51 ?g g(-1)) were significantly lower than corresponding concentrations in sediment but there was no correlation between algal and sediment concentrations. Selenium concentrations in Littorina littorea (~4 ?g g(-1)), Hediste diversicolor (2.82-12.68 ?g g(-1)), Arenicola marina (~17 ?g g(-1)) and Scrobicularia plana (1.18-6.85 ?g g(-1)) were considerably higher than concentrations in macroalga or sediment, suggesting that Se is effectively accumulated from the diet. Although Se concentrations in some invertebrates exceed toxicity thresholds for the diet of predacious birds and fish, no specific evidence for Se toxicity exists in these estuaries. PMID:23773950

  17. Biomonitoring of thallium availability in two estuaries of southwest England.

    Science.gov (United States)

    Turner, Andrew; Turner, Deborah; Braungardt, Charlotte

    2013-04-15

    Thallium is a highly toxic metal whose biogeochemical behaviour in the marine environment is poorly understood. We measured Tl in sediments, macroalgae (Fucus vesiculosus and Fucus ceranoides) and deposit-feeding invertebrates (Hediste diversicolor, Arenicola marina and Scrobicularia plana) from two estuaries of south west England (Plym and Fal) draining mineralised catchments. In the Plym, and for a given sample type, concentrations of Tl were rather invariant between sample locations and averaged about 500 ?g kg(-1) for sediment, 30 ?g kg(-1) for macroalgae and 10 ?g kg(-1) for the invertebrates. In the Fal, respective concentrations were of a similar order of magnitude but exhibited greater variation between sample locations. Normalisation of Tl concentrations to K, the biogeochemical analogue of Tl(+), revealed bioenrichment of about 20 for all organisms in the Plym and bioenrichment ranging from about 3 (H. diversicolor) to 170 (F. ceranoides) in the Fal. Despite the low bioaccumulation of Tl relative to other metals measured concurrently, it is recommended that Tl be more closely monitored and better studied in the estuarine environment. PMID:23465575

  18. 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

    Energy Technology Data Exchange (ETDEWEB)

    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, followed by scavenging in the estuary. This result indicates that particle transport models based on {sup 7}Be and trace-metal budgets must consider oceanic dissolved inputs as an additional source of {sup 7}Be and, possibly, of contaminants to estuaries.

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

    Digital Repository Service at National Institute of Oceanography (India)

    Revichandran, C.; Pylee, A.

    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...

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

    Indian Academy of Sciences (India)

    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.

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

    Directory of Open Access Journals (Sweden)

    G. D. Martin

    2010-03-01

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

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

    Digital Repository Service at National Institute of Oceanography (India)

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

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

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

    Science.gov (United States)

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

    2014-12-01

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

  4. Lames Retouchées Magdaléniennes du Morin (Gironde

    Directory of Open Access Journals (Sweden)

    Denise de SONNEVILLE-BORDES

    2009-10-01

    Full Text Available Des lames retouchées, souvent appointées ou tronquées, ont été signalées dans le Magdalénien supérieur par divers auteurs. R. de Saint-Périer notamment en figure plusieurs exemplaires provenant du Magdalénien de la Salle Saint-Martin et surtout du Magdalénien de la Grande Salle d'Isturitz, Basses-Pyrénées, Jude signale dans la couche III de la grotte de Rochereil, Dordogne, avec des lames tronquées, des lames appointées et arquées. M. et Saint-Just Péquart figurent du Magdalénien supérieur de la grotte du Mas-d'Azil, Ariège, des «lames lancéolées» et diverses lames, certaines appointées ou tronquées.Nous étudions ici la morphologie et les traces d'utilisation d'une série de lames retouchées recueillies dans le Magdalénien supérieur VI du gisement du Morin (Gironde par R. Deffarge: elles proviennent du niveau inférieur B I et des niveaux supérieurs A IV et A III.

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

    Digital Repository Service at National Institute of Oceanography (India)

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

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

  6. Artificial radionuclides in French estuaries

    International Nuclear Information System (INIS)

    Measurements were made of 238Pu, sup(239-240)Pu, 241Am, 137Cs, 144Ce, 106Ru, 125Sb and 131I in the principal rivers and estuaries of France (Seine, Loire, Gironde, Rhone). The mean specific activities due to sup(239-240)Pu in river water suspensions (5 to 10 fCi/g) are very little affected by releases from nuclear power stations. The unexpectedly high 238Pu/sup(239-240)Pu activity ratios (0.15 to 0.25) found in media subject only to atmospheric fall-out results from fractionation in the catchment areas. The high artificial radionuclide activities measured in the Seine estuary are attributed to releases from Windscale and, above all, from La Hague. The 137Cs found in Gironde river water remains associated with particles in the estuary. It decreases downstream by ion exchange in the estuary of the Loire, whereas in the Seine estuary the values recorded are higher than upstream owing to the effects of marine contamination. Particulate sup(239-240)Pu increases in all cases between the river and the estuary, a result which is in line with its frequent deficit in solution. However, the transfer of dissolved fluvial sup(239-240)Pu (0.05 to 0.2 fCi/ltr) cannot account for the excess in the particulate phase, the origin of which is ascribed to dissolved marine plutonium. (author)

  7. 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

    Science.gov (United States)

    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. ?66Zn > 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 ?66Zn = -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 ?66Zn values. Oysters had signatures varying from ?66Zn = 1.43‰ in 1983 to 1.18‰ in 2010 and were offset by ?66Zn = 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 (?66Zn ? 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 geochemical reactivity of Zn in the estuary rather than signatures of past metallurgical contaminations in the watershed as recorded in contaminated river sediments. The study also shows that the isotopic composition of Zn is strongly fractionated by its geochemical reactivity in the Gironde Estuary, representative of meso-macrotidal estuarine systems.

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

    Science.gov (United States)

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

    2014-12-01

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

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

    Digital Repository Service at National Institute of Oceanography (India)

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

    Qualitative and quantitative evolution of the Swarna estuary, Karnataka, India during the past 38 years (1967–2005), has been analysed by integrating the results of field surveys, satellite images, hydrodynamic modelling and topographic data in GIS...

  10. Detection and Enumeration of Vibrio vulnificus in Oysters from Two Estuaries along the Southwest Coast of India, Using Molecular Methods

    OpenAIRE

    Parvathi, Ammini; Kumar, H. Sanath; Karunasagar, Iddya

    2004-01-01

    This study was conducted to understand the seasonal distribution of Vibrio vulnificus in oysters from two estuaries and the effect of environmental factors on the abundance of V. vulnificus in tropical waters. V. vulnificus was detected in 56.6% of the samples tested by colony hybridization with an alkaline phosphatase-labeled oligonucleotide probe (VV-AP), and the counts ranged from

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

    Digital Repository Service at National Institute of Oceanography (India)

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

    ) and percentage of freshwater volume in the estuary are calculated in order to infer the general waste assimilative capacity and prevailing water quality conditions. Factor analysis showed a dominance of PO4–P, NO2–N, NH3–N, total...

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

    International Nuclear Information System (INIS)

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

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

    Indian Academy of Sciences (India)

    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.

  14. Climatic Facilitation of the Colonization of an Estuary by Acartia tonsa

    OpenAIRE

    Chaalali, A.; Beaugrand, G.; Raybaud, V.; Goberville, E.; V David; Boët, P.; Sautour, B.

    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 anthropog...

  15. Behavior of natural radionuclides in surficial sediments from an estuary impacted by acid mine discharge and industrial effluents in Southwest Spain.

    Science.gov (United States)

    Hierro, A; Bolivar, J P; Vaca, F; Borrego, J

    2012-08-01

    The environmental degradation resulting from the acid mine drainage (AMD) and discharge from effluents of phosphogypsum (PG) piles in the watershed of Tinto and Odiel Rivers estuary over long periods of time has resulted in significant impact on the ecosystem of this estuary, resulting that the sediments are highly polluted by heavy metals and radionuclides from the discharge AMD and leachates from the PG. During resuspension of benthic sediments some of the radionuclides are desorbed making them bioavailable. In the present study, we investigate the spatial distribution of radionuclides U, Th and Ra and assess the factors and processes that caused the spatial distribution of these nuclides in this estuarine system. This study has global significance for other polluted environmental systems that are impacted by AMD and PG. PMID:22327046

  16. Collapse of zostera noltii seagrass beds effects on nematode community structure in the Mira estuary (southwest coast of Portugal): analysis of estuarine nematodes assemblages in early recovery

    OpenAIRE

    Materatski, Patrick J. Q.

    2014-01-01

    This research focuses on the benthic nematode assemblages response during a natural recovery of the habitat, after a major collapse of the Zostera noltii, in Mira estuary (SW coast, Portugal). The main aim was attained by comparing nematode assemblages distribution patterns of density, diversity, trophic composition, biomass and morphometric attributes, between the stable ecological condition of the seagrass habitat and the early recovery process. During the early recovery no e...

  17. Behavior of natural radionuclides in surficial sediments from an estuary impacted by acid mine discharge and industrial effluents in Southwest Spain

    International Nuclear Information System (INIS)

    The environmental degradation resulting from the acid mine drainage (AMD) and discharge from effluents of phosphogypsum (PG) piles in the watershed of Tinto and Odiel Rivers estuary over long periods of time has resulted in significant impact on the ecosystem of this estuary, resulting that the sediments are highly polluted by heavy metals and radionuclides from the discharge AMD and leachates from the PG. During resuspension of benthic sediments some of the radionuclides are desorbed making them bioavailable. In the present study, we investigate the spatial distribution of radionuclides U, Th and Ra and assess the factors and processes that caused the spatial distribution of these nuclides in this estuarine system. This study has global significance for other polluted environmental systems that are impacted by AMD and PG. - Highlights: ? Tinto–Odiel rivers estuary affected by AMD and leaching from phosphogypsum. ? Study about distribution processes that govern Ra, U and Th-isotopes in sediments. ? The acidity gradients of mixed waters (pH) regulate the U and Th distribution. ? Significant pollution by U has been found for pH = 3.5–4.5.

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

    Science.gov (United States)

    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

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

    International Nuclear Information System (INIS)

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

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Digital Repository Service at National Institute of Oceanography (India)

    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...

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

    Digital Repository Service at National Institute of Oceanography (India)

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

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

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

    Science.gov (United States)

    Patino, Eduardo

    2014-01-01

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

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

    International Nuclear Information System (INIS)

    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)

  5. Introduction to Estuaries

    Science.gov (United States)

    Estuaries, although minor geographical features at the global scale, have major importance for society and the world’s economies. This chapter introduces estuaries by presenting an overview of definitions, origins, physical, chemical and ecological attributes, and the interaction...

  6. Estuary Classification Revisited

    CERN Document Server

    Guha, Anirban

    2012-01-01

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

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

    OpenAIRE

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

    1998-01-01

    During the spring 1995 (2-25 May), a cruise was carried on the RV Poseidon (Germany) on the continental shelf of the south Bay of Biscay. The objective was a comprehensive study of the planktonic food web within the Gironde plume waters. In these waters phosphate was present at very low concentrations (undetectable to < 0.1 mu mol.L-1), whereas nitrate, silicate and ammonium concentrations were much higher (several mu mol.L-1 for nitrate and silicate and 0.5 to 1.0 mu mol.L-1 for ammonium). T...

  8. Trophic functioning of coastal ecosystems along an anthropogenic pressure gradient: A French case study with emphasis on a small and low impacted estuary

    Science.gov (United States)

    Selleslagh, Jonathan; Lobry, Jérémy; Amara, Rachid; Brylinski, Jean-Michel; Boët, Philippe

    2012-10-01

    The ecological functioning of various French coastal ecosystems, with special emphasis on the Canche estuary, along an anthropogenic pressure gradient was studied using mass-balanced trophic models in order to test the relevance of functional indices assessing the ecological status of coastal systems. A trophic model of the Canche (eastern English Channel, France) estuarine food web was constructed using an Ecopath approach to determine the structure and functioning of energy flows in the trophic network. The model consisted of 15 compartments, from primary producers (trophic level TL = 1) to the top consumers (fish, TL = 3.8). Input parameters were mainly computed from field studies conducted between 2006 and 2007. Results showed that the majority of flows came from detritus, which is an important energy source in the ecosystem, as indicated by mixed trophic impacts. Keystone index (KSI) revealed that amphipods, copepods, gobies and European eel were identified as key compartments in the Canche estuarine food web, with the first two considered as important vectors for carbon transfer from detritus to top predators. The Canche estuary trophic network has a low recycling level (FCI = 0.8%), a low total system throughput (TST = 1364 gC. m-2. y-1) and a low ascendency (A = 1439 gC. m-2. y-1), but a relatively low connectivity (CI = 0.33), high internal relative ascendency (Ai/Ci = 35.6%) and a high omnivory index (OI = 0.04), indicating that this estuary is immature but relatively organised and complex, with strong production but which little is used as the estuary depends on external exchanges. In addition, the Canche estuary, recognised as a small and low impacted estuarine ecosystem, was compared with six other French coastal systems: the bay of Somme, the Seine estuary, the Mont Saint-Michel bay, the Loire estuary, the Pertuis Charentais and the Gironde estuary, where Ecological Network Analyses (ENA) have been applied using similar methods. Compared with the other six coastal systems, the Canche estuary did not present a similar functioning to close geographically estuaries or estuaries with similar environmental characteristics. The results of the present study showed that among computed ENA indices, the omnivory index (OI) was positively correlated with an anthropogenic pressure index, suggesting that such a functional index can be useful for assessing the ecological quality of estuarine and coastal systems.

  9. NEPmap (National Estuary Program Mapper)

    Data.gov (United States)

    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...

  10. DELAWARE ESTUARY PCB MODEL

    Science.gov (United States)

    The Delaware River Basin Commission recently completed the first phase of a program to develop and implement Total Maximum Daily Loads (TMDLs) for toxic pollutants for the Delaware Estuary. This complex body of water extends from the head of tide at Trenton, NJ (River Mile 133.2...

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

    OpenAIRE

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

    2010-01-01

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

  12. ¡Salud! Southwest Tour

    OpenAIRE

    Joanna Mae Mae Souers

    2009-01-01

    During this summer of 2009, 12 American medical students from the Escuela Latinoamericana de Medicina (ELAM – Latin American School of Medicine) in Havana, Cuba will board a Recreational Vehicle (RV) to travel across the Southwest region of the United States visiting a number of tribal settlements of American Indian Nations, community colleges and universities. While at the various sites the students will share their personal experiences of what it’s like to study at ELAM while promoting the ...

  13. FLORA OF MOLOCHNYI ESTUARY COASTS

    Directory of Open Access Journals (Sweden)

    Kolomiychuk V.P.

    2013-09-01

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

  14. The Mandovi and Zuari estuaries

    Digital Repository Service at National Institute of Oceanography (India)

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

    . Chandramohan .................... 3 Chapter 2 Tides and sea-level variability S. R. Shetye, I. Suresh, and D. Sundar ................... 29 Chapter 3 Numerical models A. S. Unnikrishnan and N. T. Manoj .................... 39 Chapter 4 Mixing and intrusion... made so far to simulate them in numerical models, and characteristics of stratification and mixing. These are followed by chapters that examine the fun- damentals of biology and chemistry of the estuaries. A distinct characteristic of the estuaries...

  15. Go Southwest, Old Man

    OpenAIRE

    Materassi, Mario

    2009-01-01

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

  16. ¡Salud! Southwest Tour

    Directory of Open Access Journals (Sweden)

    Joanna Mae Mae Souers

    2009-06-01

    Full Text Available During this summer of 2009, 12 American medical students from the Escuela Latinoamericana de Medicina (ELAM – Latin American School of Medicine in Havana, Cuba will board a Recreational Vehicle (RV to travel across the Southwest region of the United States visiting a number of tribal settlements of American Indian Nations, community colleges and universities. While at the various sites the students will share their personal experiences of what it’s like to study at ELAM while promoting the availability of full scholarships for students, volunteer their services while learning about some of the more significant health concerns affecting American Indian populations and to build personal and professional relationships with health care practitioners and members of Native American communities.

  17. Oil spill trajectory analysis for the Calcasieu Estuary

    International Nuclear Information System (INIS)

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

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

    Indian Academy of Sciences (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.

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

    International Nuclear Information System (INIS)

    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 the biogeochemistry of Cd, Co and Cs in the estuarine environment and the knowledge obtained on the field. Experiments performed both in laboratory and in situ were necessary to check the validity of the assumptions of the model and to evaluate model parameters, which cannot be measured directly like to the sorption properties of natural particles. Radiotracers (109Cd, 57Co,134Cs) were used to determine physico-chemical key processes and environmental variables that control the speciation and the fate of Cd, Co and Cs. This approach, based on the use of spike with various radionuclides, allowed us to evaluate the affinity constants of particles to the four estuaries for the studied metals (global intrinsic complexation and exchange constants) and also the exchangeable particulate fraction estimated from the comparison of measured natural metals coefficients of distribution and coefficient of distribution of their radioactive equivalents. Other parameters, which are necessary to build the model (specific surface area, concentration of active surface sites, mean intrinsic acid-base constants,...), were independently estimated by various experimental approaches, applied in laboratory to particle samples taken throughout estuaries (electrochemical measurements, nitrogen adsorption using the BET method,...). The results of the validation indicate that in spite of its simplifications, the model reproduces in a satisfactory way the dissolved/particulate distributions measured for Cd, Co and Cs. With a predictive aim, this type of model must be coupled with a hydro-sedimentary transport model. (author)

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

  3. 75 FR 34975 - Notice of Estuary Habitat Restoration Council's Intent to Revise its Estuary Habitat Restoration...

    Science.gov (United States)

    2010-06-21

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

  4. 75 FR 61790 - Capital Southwest Corporation; Notice of Application

    Science.gov (United States)

    2010-10-06

    ... unduly complicate Capital Southwest's structure because equity-based compensation arrangements are widely... COMMISSION Capital Southwest Corporation; Notice of Application September 29, 2010. AGENCY: Securities and...: Applicant, Capital Southwest Corporation (``Capital Southwest''), requests an order to permit it to...

  5. Environmental data management in the Sado Estuary

    OpenAIRE

    Caeiro, Sandra Sofia Ferreira da Silva

    2004-01-01

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

  6. Sea level variability in South African estuaries

    Scientific Electronic Library Online (English)

    Eckart H., Schumann.

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

  7. Morphodynamic equilibrium of alluvial estuaries

    Science.gov (United States)

    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 equilibrium state is reached through an erosional wave, which leads to bed degradation of the upstream 'fluvial reach'. For a given river discharge, the length of the tidal reach increases quite rapidly with tidal amplitude, up to some threshold value of the tidal amplitude above which the length of the estuary becomes comparable with the length of the tidal wave. When the channel plan-form is convergent, deposition of sediments of fluvial origin in the funnel-shaped region drastically changes the equilibrium configuration. The effect of an increasing channel convergence is thus to induce bed aggradation close to the inlet. Nevertheless, tidal forcing only slightly changes the non-tidal profile. The effect of increasing tidal oscillations again leads to an increase of the bed slope at the inlet and to a general bed degradation upstream. The effects of varying sediment supply, flow discharge and river width in the upstream reach have also been investigated and play an important role. Further geomorphological implications of these results will be discussed at the meeting. References Dalrymple, R. W., and K. Choi (2007), Morphologic and facies trends through the fluvialmarine transition in tide-dominated depositional systems: A schematic framework for environmental and sequence-stratigraphic interpretation, Earth-Science Reviews, 81(3-4), 135-174, doi:10.1016/j.earscirev.2006.10.002. Seminara, G., M. Bolla Pittaluga, and N. Tambroni (2012), Morphodynamic equilibrium of tidal channels, Environmental Fluid Mechanics: Memorial Volume in Honour of Prof. Gerhard H. Jirka, 153-174

  8. Smoking rates low in southwest

    OpenAIRE

    Robbins RA.

    2014-01-01

    No abstract available. Article truncated at 150 words. The Gallup survey confirms that smoking rates in the US are declining and that smoking rates are lower in the Southwest than the US as a whole (1). Nationally, the smoking rate fell to 19.7% in 2013 from 21.1% in 2008. Among the Southwest states California ranked second (15.0%), Colorado ninth (17.4%), and Arizona tenth (17.5%). Only New Mexico was above the Nation's average at 20.0%. Utah remains the state with the lowest percentage of s...

  9. Southwest Airlines: lessons in loyalty.

    Science.gov (United States)

    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

  10. Dissolved Oxygen Data for Coos Estuary (Oregon)

    Science.gov (United States)

    The purpose of this product is the transmittal of dissolved oxygen data collected in the Coos Estuary, Oregon to Ms. Molly O'Neill (University of Oregon), for use in her studies on the factors influencing spatial and temporal patterns in dissolved oxygen in this estuary. These d...

  11. Sedimentary organic and inorganic records of eutrophication and hypoxia in and off the Changjiang Estuary over the last century.

    Science.gov (United States)

    Zhao, Jun; Feng, Xuwen; Shi, Xiaolai; Bai, Youcheng; Yu, Xiaoguo; Shi, Xuefa; Zhang, Weiyan; Zhang, Rongping

    2015-10-15

    Organic and inorganic sedimentary parameters in and off the Changjiang Estuary have been analyzed to reconstruct historical trends in eutrophication and hypoxia over the last century. The lipid biomarker concentrations in the Changjiang Estuary mud area (CEMA) indicated eutrophication accelerated after the 1970s. Meanwhile, Mo/Al indicated hypoxia has increased since 1960s. Eutrophication and hypoxia in the CEMA are primarily a result of the dramatically increased load of terrestrial nutrients from the Changjiang to the East China Sea. The lipid biomarker concentrations in the southwest Cheju Island mud area (SCIMA) showed primary production is controlled mainly by changes in regional climate and marine current. No significant hypoxia occurred in the SCIMA over the past century as indicated by Mo/Al. Therefore, geochemical indicators of eutrophication and hypoxia revealed different patterns between the CEMA and SCIMA, suggesting the role of river-derived nutrients in sustaining eutrophication and hypoxia in the CEMA since the 1960s. PMID:26233303

  12. Water Column Methylation in Estuaries

    Science.gov (United States)

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

    2014-12-01

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

  13. SEMINATURAL SILVICULTURE IN SOUTHWEST GERMANY

    Directory of Open Access Journals (Sweden)

    Peter Spathelf

    2009-10-01

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

  14. Mercury sources and transformations in a man-perturbed tidal estuary; the Sinnamary Estuary, French Guiana

    OpenAIRE

    Muresan, B; Cossa, Daniel; Coquery, M.; Richard, S

    2008-01-01

    The distribution, partition and speciation of mercury (Hg) were studied along the redox gradient of an anthropogenically perturbed tropical estuary, the Sinnamary Estuary in French Guiana. This system is a partially mixed estuary characterized by an anoxic freshwater end-member, while the marine end member consists of the Amazon Plume. The set up of an artificial oxygenation system in the anoxic freshwater end-member generates sharp gradients of major chemical species (iron, sulfides, etc.) c...

  15. [Environmental characteristics of heavy metals in surface sediments from the Huanghe estuary].

    Science.gov (United States)

    Wu, Bin; Song, Jin-Ming; Li, Xue-Gang

    2013-04-01

    The contents of Cu, Pb, Zn, Cr, As and Hg in surface sediment from 14 sampling sites in the Huanghe estuary during July-August, 2011 were measured to investigate environmental geochemical characteristics of heavy metals related to multiple factors. The distribution, relationship with fine fraction and TOC, and sediment quality assessment concerning heavy metals were analyzed. The results showed that average concentrations of Cu, Pb, Zn, Cr, As and Hg in the Huanghe estuary were (16.5 +/- 2.7), (16.0 +/- 3.4), (21.0 +/- 3.3), (17.4 +/- 3.1), (6.5 +/- 1.2), (0.0444 +/- 0.0307) mg x kg(-1), respectively, which were lower than those in other typical areas along the coast of China. The distribution of metals displayed higher profiles in south than that in north of the Huanghe estuary, with a trend of increase seaward, especially for stations in southwest of the Laizhou bay. The insignificant correlation among metals indicated the complex sources of heavy metals in flood season. Pearson correlation was also conducted between metal contents and percentage of fine particulates and TOC, which was also insignificant, suggesting heavy metal concentration and distribution in the study region were also controlled by other factors except grain size and TOC. There was a good correlation between clay fraction and TOC (r = 0.724, P < 0.05), indicating TOC tends to accumulate in clay. Compared with variety of background values and an internationally used consensus-based sediment quality guidelines (CBSQGs) for saltwater ecosystem, heavy metals in surface sediments from the Huanghe estuary implied a low probability of toxic effect, despite a sharp contamination trend pertaining to Hg and Pb since 1980s. PMID:23798109

  16. Estimating bankfull discharge and depth in ungauged estuaries

    Science.gov (United States)

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

    2015-04-01

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

  17. National Estuary Program Study Area Boundaries

    Data.gov (United States)

    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...

  18. Microplastic in three urban estuaries, China.

    Science.gov (United States)

    Zhao, Shiye; Zhu, Lixin; Li, Daoji

    2015-11-01

    Estuarine Microplastics (MPs) are limited to know globally. By filtering subsurface water through 330 ?m 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 (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

  19. PCBs in phytoplankton in the Odra Estuary

    OpenAIRE

    Joanna Konat-Stepowicz; Gra?yna Kowalewska

    2003-01-01

    Eleven PCB congeners were determined in phytoplankton samples collected from the Odra Estuary at 9 stations in 2001-2002. The PCB concentrations were related to the temperature, turbidity, salinity, oxygen and redox potential of the water as well as to the pigment content in the samples. The results indicate that phytoplankton and the detritus derived from it play a crucial role in the distribution of PCBs, their transfer from the water column to sediments and from the Estuary to the sea. The...

  20. Tidal Heights in Hyper-Synchronous Estuaries

    OpenAIRE

    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...

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

    Digital Repository Service at National Institute of Oceanography (India)

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

    immune from extended hypoxia/anoxia and maintaining the health of the Cochin estuary. For the seasonally varying river flow in the estuary, salt intrusion receded with increasing river flow in monsoon and rebounded with decreasing river flow in dry season...

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

    Digital Repository Service at National Institute of Oceanography (India)

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

    several decades have resulted in considerable shrinkage of the Cochin backwaters [13]. The hydraulic barriers constructed to prevent saline incursion into the upstream agricultural fields imposed flow-restrictions and increased sedimentation...

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

    Digital Repository Service at National Institute of Oceanography (India)

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

    on various parameters-water level, alongshore and crossshore currents, temperature, and salinity-revealed the relative dominance of the various tidal constituents. The water temperature peaked during late afternoon, suggesting solar forcing, whereas salinity...

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

    International Nuclear Information System (INIS)

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

  5. Smoking rates low in southwest

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2014-04-01

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

  6. Skagit IMW (Skagit River Estuary Intensively Monitored Watershed Project)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This study evaluates system-level effects of several estuary restoration projects on juvenile Chinook salmon production in the Skagit River estuary. The monitoring...

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

    Science.gov (United States)

    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 ?13C values and showed that several mangrove fish species have significant intraspecies variability in feeding habits, possibly due to high intraspecific competition.

  8. Sediment transport processes in estuaries: An introduction

    Science.gov (United States)

    Perillo, Gerardo M. E.; Lavelle, J. William

    1989-10-01

    Research on estuarine sediment transport processes has received increasing attention in recent years, attention related to concerns about water clarity, pollutant distribution and transport, dredge spoil disposal, creation and maintenance of channels and basins for navigational purposes, and shoreline erosion. Still, the geophysical community that addresses these concerns and the underlying fundamentals of sediment transport in an estuary is widely but relatively sparsely distributed around the world. The need to draw these researchers together to discuss ideas and outlooks led to the AGU Chapman Conference on Sediment Transport Processes in Estuaries that was held at the Universidad Nacional del Sur in Bahía Bianca, Argentina, from June 13 to June 17, 1988 [Perillo and Lavelle, 1988]. The meeting sought to provide a timely impetus to further progress in sediment transport research in estuaries, promote communication among researchers using different investigatory approaches, and develop collaborations among estuarine scientists in developed and developing nations.

  9. The impact of coal production on the sediment record of the Severn Estuary

    Energy Technology Data Exchange (ETDEWEB)

    French, P.W. [University of London, Egham (United Kingdom). Dept. of Geography

    1998-12-31

    A link between historical coal production and sediment coal concentrations in saltmarsh sediments is demonstrated for the Severn Estuary, southwest Britain. It is clear that whilst coal production has varied in accordance with industrial demand, the environmental impact has been manifested in a corresponding increase in environmental pollution. Furthermore, the transfer of coal between production site and estuarine sediment has introduced a lag period into the transfer mechanism, argued to be of different periods by different authors, but generally agreed to exist. With coal production at the present time effectively zero, it can be argued that new input has to come from contaminated sediments already present within the Estuary. Current estimates indicate that the inertial mudflat sediments of the contemporary system currently hold around 10{sup 5}-10{sup 6} tonnes of coal, whilst erosion of the three marshes studied here suggest an input of coal from this source ranging from 76 to 134 tonnes a{sup -1}. As a consequence, both contemporary mudflats and saltmarshes must both be regarded as potential future coal pollution sources. 17 refs., 4 figs., 1 tab.

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

    Science.gov (United States)

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

    2015-08-01

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

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

    Indian Academy of Sciences (India)

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

    2015-08-01

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

  12. Estuary wader capacity following severe weather mortality

    International Nuclear Information System (INIS)

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

  13. Southwest Florida Shelf Ecosystems Analysis Study

    Data.gov (United States)

    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,...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-07-01

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

  15. Geochemical studies in the Godavari Estuary, India

    Digital Repository Service at National Institute of Oceanography (India)

    Somayajulu, B.L.K.; Martin, J.M.; Eisma, D.; Thomas, A.J.; Borole, D.V.; Rao, K.S.

    are reported. The DOC and Fe concentrations are lower compared with those in other estuaries of the world and are below the average value reported for world rivers. Silicon behaves non-conservatively; its depletion which is most likely due to biological...

  16. Estuaries and Tidal Marshes. Habitat Pac.

    Science.gov (United States)

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

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

  17. Radiological assessment of the Esk Estuary

    International Nuclear Information System (INIS)

    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)

  18. Mercury in sediments of Ulhas estuary

    Digital Repository Service at National Institute of Oceanography (India)

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

    ranges of dissolved (0.04-0.61 mu g l u-1) and particulate (1.13-6.43 mu g g u-1) Hg reveal a definite enhancement of levels in the estuary. The Hg burden in sediment upstream of the weir that limits the tidal influence is low (0.08-0.19 mu g g u-1...

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

    Science.gov (United States)

    Chen, XinJian

    2012-06-01

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

  20. Nutrient budgets for large Chinese estuaries

    Directory of Open Access Journals (Sweden)

    S. M. Liu

    2009-10-01

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

  1. Nutrient budgets for large Chinese estuaries

    Science.gov (United States)

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

    2009-10-01

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

  2. Epipelic diatoms in the estuaries of South Africa

    Scientific Electronic Library Online (English)

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

    2013-01-01

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

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

    Science.gov (United States)

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

    2005-01-01

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

  4. Second International Symposium on the Biogeochemistry of Model Estuaries: Estuarine processes in global change. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Windom, H.L.

    1991-12-31

    This report summarizes estuary events discussed at the symposium on biogeochemistry. Topics include; sedimentation, salinity, inputs and outputs of the estuary, effects of global change, and the need for effective sampling and modeling of estuaries.

  5. 76 FR 8345 - Endangered and Threatened Species; Recovery Plan Module for Columbia River Estuary Salmon and...

    Science.gov (United States)

    2011-02-14

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

  6. Interpreting the colour of an estuary

    Science.gov (United States)

    Bowers, D. G.; Evans, D.; Thomas, D. N.; Ellis, K.; Williams, P. J. le B.

    2004-01-01

    This paper explores the possibility of using water colour to quantify the concentration of coloured dissolved organic matter (CDOM), and through it, dissolved organic carbon (DOC) and salinity in a turbid estuary in which suspended sediments also influence water colour. The motivation of the work is that the method could be applied to water colour measurements made remotely from an aircraft (or, in larger estuaries, a satellite) enabling near-synoptic mapping of surface salinity and DOC distributions. The paper describes observations at 29 stations distributed along the salinity gradient of the Conwy estuary in North Wales. At each station, surface water samples were collected and analysed for salinity, concentrations of DOC, chlorophyll and suspended particles and absorption spectra of CDOM, or yellow substance. Profiles were made of both upwelling and downwelling irradiance in four narrow band channels, and these were used to calculate irradiance reflection and attenuation coefficients. Results show that spectrally averaged light absorption in the estuary is caused principally and equally by mineral suspended solids and yellow substance, with water and chlorophyll in third and fourth place. The CDOM is strongly correlated ( R2=0.99) in a negative sense with salinity, and more weakly correlated with DOC. There is a linear relationship between CDOM and the ratio of reflection coefficients in the red (670 nm) and blue-green (490 nm) parts of the spectrum, which could be applied to remote sensing; the slope and intercept of the relationship are however different to those found in less turbid water bodies. It is shown that the change in slope and intercept are consistent with the presence, in the Conwy estuary, of suspended particles which influence the water colour. A method is described and tested for inverting water colour measurements in a turbid estuary to give estimates of CDOM in the presence of suspended particles. The solution, which has not been adjusted to fit the data, produces profiles of CDOM, DOC and salinity, which behave reasonably but which currently have a limited accuracy. RMS differences between measured and optically derived parameters for the entire data set are 0.27 m -1 (CDOM), 4 PSU (salinity) and 67 ?M (DOC) although better accuracy is obtained on individual surveys. The fact that there is little bias between predicted and observed parameters indicates that much of the scatter is caused by random measurement error and that the approach is fundamentally sound.

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

    Science.gov (United States)

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

    2015-10-01

    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.

  8. Salt intrusion, tides and mixing in multi-channel estuaries:

    OpenAIRE

    Nguyen, A. D.

    2008-01-01

    Multi-channel estuaries, such as the Mekong Delta in Vietnam and the Scheldt in the Netherlands, have characteristics of both the river and the sea, forming a unique environment influenced by tidal movements of the sea and freshwater flow of the river. This study addresses a number of knowledge gaps in multi-channel estuaries by developing a predictive analytical approach for salinity intrusion and discharge estimate in multi-channel estuaries. The new approach agrees well with 1-D hydrodynam...

  9. Relation between tidal damping and wave celerity in estuaries:

    OpenAIRE

    Savenije, H. H. G.; Veling, E.J.M.

    2005-01-01

    Observations in estuaries indicate that an amplified tidal wave moves considerably faster than is indicated by the classical equation for wave propagation. Similarly, the celerity of propagation is lower if the tidal wave is damped. This phenomenon is clearly observed in the Schelde estuary (located in the Netherlands and Belgium) and in the Incomati estuary in Mozambique. In the Incomati, the tidal wave is damped throughout, whereas in the Schelde the tidal range increases from the mouth unt...

  10. SOUTHWEST REGIONAL PARTNERSHIP ON CARBON SEQUESTRATION

    Energy Technology Data Exchange (ETDEWEB)

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

    2004-11-01

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

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

    International Nuclear Information System (INIS)

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

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

    DEFF Research Database (Denmark)

    Lund-Hansen, Lars Chresten; Nhu Hai, Doan; 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 properties in a tropical wet and dry estuary are compared and discussed in relation to those of temperate estuaries. Sampling in the Nha Phu estuary, Vietnam, consisted of five stations on a transect from hea...

  13. 2005 Southwest Florida Water Management District (SWFWMD) Lidar: Manatee District

    Data.gov (United States)

    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...

  14. SOUTHWEST REGIONAL PARTNERSHIP ON CARBON SEQUESTRATION

    Energy Technology Data Exchange (ETDEWEB)

    Brian McPherson

    2005-08-01

    The Southwest Partnership on Carbon Sequestration completed several more tasks during the period of October 1, 2004--March 31, 2005. The main objective of the Southwest Partnership project is to achieve an 18% reduction in carbon intensity by 2012. Action plans for possible Phase 2 carbon sequestration pilot tests in the region are completed, and a proposal was developed and submitted describing how the Partnership may develop and carry out appropriate pilot tests. The content of this report focuses on Phase 1 objectives completed during this reporting period.

  15. Reducing fertilization for maize in Southwest Spain

    OpenAIRE

    Fernández Luque, José Enrique; Murillo Carpio, José Manuel; Moreno Lucas, Félix; Cabrera, Francisco; Fernández Boy, E.

    1998-01-01

    A high nitrate pollution of groundwaters has been detected in recent years in many areas of southwest Spain where maize is cropped. This may be caused by the high fertilization level used in those areas. In this work, maize was grown consecutively for six years (1991-96) under Mediterranean management practices in the Guadalquivir River Valley (southwest Spain), using both a fertilization level widely used in the area (510 kg N ha-1 yr-1) and one third of it. The effect of the reduced fertili...

  16. Phosphorous dynamics in a temperate intertidal estuary

    OpenAIRE

    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.

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

    Science.gov (United States)

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

    2015-07-01

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

  18. Sedimentary Rocks and Methane - Southwest Arabia Terra

    Science.gov (United States)

    Allen, Carlton C.; Oehler, Dorothy Z.; Venechuk, Elizabeth M.

    2006-01-01

    We propose to land the Mars Science Laboratory in southwest Arabia Terra to study two key aspects of martian history the extensive record of sedimentary rocks and the continuing release of methane. The results of this exploration will directly address the MSL Scientific Objectives regarding biological potential, geology and geochemistry, and past habitability.

  19. Mexican-Americans in the Southwest.

    Science.gov (United States)

    Galarza, Ernesto; And Others

    With findings as presented in this 1969 book, a 2-year field study conducted by a 3-member team analyzed the economic, cultural, political, and educational conditions of Mexican Americans in the Southwest (California, Arizona, New Mexico, Colorado, and Texas) with some reference to braceros and the situation in Mexico. An overview of 8 geographic…

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

    Science.gov (United States)

    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

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

    Scientific Electronic Library Online (English)

    Alicia, González-Solis; Daniel, Torruco.

    2013-12-01

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

  2. Time-dependence of salinity in monsoonal estuaries

    Digital Repository Service at National Institute of Oceanography (India)

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

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

  3. Mercury sources and transformations in a man-perturbed tidal estuary: The Sinnamary Estuary, French Guiana

    Science.gov (United States)

    Muresan, B.; Cossa, D.; Coquery, M.; Richard, S.

    2008-11-01

    The distribution, partition and speciation of mercury (Hg) were studied along the redox gradient of an anthropogenically perturbed tropical estuary, the Sinnamary Estuary in French Guiana. This system is a partially mixed estuary characterized by an anoxic freshwater end-member, while the marine end-member consists of the Amazon Plume. The set up of an artificial oxygenation system in the anoxic freshwater end-member generates sharp gradients of major chemical species (iron, sulfides, etc.) coupled with intense organic matter (OM) turnover. The coexistence of oxygenated waters and dissolved sulfides in an organic rich environment depicts the Upper Sinnamary Estuary (USE: part of Sinnamary Estuary under the tidal influence but upstream of the salt intrusion) as a potential site for Hg methylation. The concentrations of all mercury compounds (HgT) in the unfiltered samples (HgT UNF), in the dissolved (HgT D) and particulate (HgT P) phases of the USE average 11 ± 3, 6 ± 2 and 5 ± 3 (i.e. 600 ± 200 pmol g -1) pmol L -1, respectively. Average concentrations of monomethylmercury (MMHg) in the unfiltered (MMHg UNF), dissolved (MMHg D) and particulate (MMHg P) phases were 3.7 ± 1.0, 2.0 ± 0.9 and 1.8 ± 1.2 (i.e. 220 ± 130 pmol g -1) pmol L -1, respectively. Water oxygenation and sulfides concentrations emerged to play a critical role in controlling MMHg levels. Additionally, iron cycling, acid-base mechanisms, and redox-dependent processes were involved in the MMHg partitioning between phases. Overall, the USE constitutes a biogeochemical reactor that gathers partitioning and methylation processes. The permanent MMHg inputs from the anoxic freshwater end-member combined with the intense endogenous Hg methylation ensures high-MMHg levels in both dissolved and particulate phases. To illustrate, the USE exports 60 ± 20% more MMHg UNF than it imports: 5.5 ± 0.7 vs. 3.5 ± 1.2 kg year -1.

  4. Southwest Regional Partnership on Carbon Sequestration

    Energy Technology Data Exchange (ETDEWEB)

    Brian McPherson

    2006-03-31

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

  5. Carbon and nitrogen isotopic composition of suspended particulate organic matter in Zuari Estuary, west coast of India

    Science.gov (United States)

    Bardhan, Pratirupa; Karapurkar, S. G.; Shenoy, D. M.; Kurian, S.; Sarkar, A.; Maya, M. V.; Naik, H.; Varik, S.; Naqvi, S. W. A.

    2015-01-01

    The spatio-temporal variations of the ?13C and ?15N of suspended particulate organic matter (SPOM), along with ancillary chemical and hydrographic parameters, have been examined monthly for one year (October 2010 to September 2011) at a total of seven stations to refine the understanding of SPOM sources and biogeochemical pathways in the tropical Zuari Estuary, west coast of India. The dynamic nature of C and N cycling in estuaries is reflected in the isotopic variation of SPOM as a function of space and time. The results exhibit marked seasonality, with the autochthonous component and the terrestrial component being the major SPOM sources during periods of low and high river discharges, respectively. Spatially, enrichments of ?13C and ?15N from the head (?13C = - 29.6‰, ?15N = 1.78‰, C/N = 7.09) to the mouth (?13C = - 20.9‰, ?15N = 5.77‰, C/N = 6.12) of the estuary indicate downstream reduction of terrigenous influence. The mean C:N ratios varied between 4 and 9 over the study period with low values during the monsoon, in spite of large terrestrial input, which can be attributed to microbial modification of terrestrial SPOM. A significant positive correlation of ?13C with salinity suggests the reliability of ?13C as a biogeochemical tracer for organic matter provenance. Carbon:chlorophyll plots reveal suppressed autochthonous production during the southwest monsoon which may be attributed to the rapid flushing time, light-limitation due to cloud cover and high water-column turbidity.

  6. Indian estuaries: Dynamics, ecosystems, and threats

    Digital Repository Service at National Institute of Oceanography (India)

    Shetye, S.R.

    stream_size 25327 stream_content_type text/plain stream_name Natl_Acad_Sci_Lett_34_229p.pdf.txt stream_source_info Natl_Acad_Sci_Lett_34_229p.pdf.txt Content-Encoding UTF-8 Content-Type text/plain; charset=UTF-8 LEAD ARTICLE... to have a situation peculiar to it. Each needs to be studied so that a plan can be drawn to manage it. Gathering data on the large number of estuaries poses a challenge. It also offers an opportunity. Educational institutions, colleges, and university...

  7. Carbon dioxide emissions from Indian monsoonal estuaries

    Digital Repository Service at National Institute of Oceanography (India)

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

    taken from Dam authorities of respective river. # Dr. S.R. Shetye Personnal communication. Figure 1: Figure 2: 0 1000 2000 3000 4000 River discharge (m 3 s -1 ) 0 4000 8000 12000 16000 20000 pC O 2 ( ? at m ) 60 70 80 90 100 110 O 2...- 1717. Raymond, P.A., and C.S. Hopkinson (2003). Ecosystem modulation of dissolved carbon age in a temperate marsh-dominated estuary. Ecosystems, 6, 694-705. Souza, M.F., V.R. Gomes, S.S. Freitas, R.C.B. Andrade, and B. Knoppers (2009). Net...

  8. Distribution of U-Th nuclides in the riverine and coastal environments of the tropical southwest coast of India

    International Nuclear Information System (INIS)

    A reconnaissance study has been made on the distribution of 238U, 234U, 232Th and 230Th in soils, water, suspended particulate matter (SPM) and bottom sediments in the Kali river basin around Kaiga, its estuarine region and the adjacent Arabian Sea to obtain the baseline data of U-Th series nuclides in view of the commissioning of nuclear power reactors at Kaiga, near Karwar, on the southwest coast of India. Drainage basin soils developed over greywackes (the dominant litho-unit upstream) are lower in 238U/Al and 232Th/Al ratios by factors of 3-5 in comparison with those developed over tonalitic gneisses (the dominant litho-unit downstream). The dominance of the former type of soils is reflected in the composition of river-bottom sediments derived from the upstream drainage basin during the monsoon. The 232Th in bottom sediments tends to increase towards the estuarine and coastal areas, presumably due to deposition of heavy minerals and onshore transport of coastal sediments into the estuary. The dissolved U in the Kali river is low (0.001-0.02 ?g/l) when compared to the major Indian rivers as the Kali river flows through U-poor greywackes. Thus, the input of dissolved U to the Kali estuary is dominated by sea water. Although there is some evidence for the removal of dissolved U at low salinity during estuarine mixing, its behaviour is conservative in the lower estuary (at higher salinities). The removal rate of dissolved U from the Kali river basin is similar to that reported from other tropical river basins. The U flux from all the west-flowing rivers of Peninsular India is estimated at 26.3x106 g/yr to the Arabian Sea which is about 2% of the flux from the Himalayan rivers to the Bay of Bengal

  9. Lames Retouchées Magdaléniennes du Morin (Gironde)

    OpenAIRE

    De Sonneville-Bordes, Denise; Deffarge, R.

    2009-01-01

    Des lames retouchées, souvent appointées ou tronquées, ont été signalées dans le Magdalénien supérieur par divers auteurs. R. de Saint-Périer notamment en figure plusieurs exemplaires provenant du Magdalénien de la Salle Saint-Martin et surtout du Magdalénien de la Grande Salle d'Isturitz, Basses-Pyrénées, Jude signale dans la couche III de la grotte de Rochereil, Dordogne, avec des lames tronquées, des lames appointées et arquées. M. et Saint-Just Péquart figurent du Magdalénien supérieur de...

  10. Cyanobacteria and macroalgae in ecosystem of the Neva estuary

    Directory of Open Access Journals (Sweden)

    Nikulina V. N.

    2011-07-01

    Full Text Available The Baltic Sea and Neva estuary are plagued by coastal eutrophication. In order to estimate the scale of the problem, quantitative estimates of phytoplankton and macroalgal mats were determined in the Neva estuary. Long-term monitoring (1982–2009 of phytoplankton showed changes in its species composition and abundance. Summer phytoplankton biomass increased significantly in the 1990s, with concomitant changes in species composition, despite a decline of nutrients in the Neva estuary. The cyanobacteria Planktothrix agardhii became a dominant species. The summer biomass of phytoplankton reached a maximum of 5.2 ± 0.4 mg·L-1 in 2002–2004. Monitoring of macroalgal community in the coastal area of the Neva estuary from 2002 to 2009 showed the dominance of the filamentous green alga Cladophora glomerata in the phytobenthos. Average biomass of macroalgae in inner and outer estuary differed significantly at 132 ± 29 and 310 ± 67 g DW·m-2, respectively. This study showed, that fluctuations in macroalgal biomass reflected human influence on estuary, although it was less sensitive to human impact than the phytoplankton community. Thus qualitative and quantitative characteristics of phytoplankton and macroalgal blooms can indicate anthropogenic influence on the ecosystem, and help to better manage the Neva estuary.

  11. Summer hypoxia adjacent to the Changjiang Estuary

    Science.gov (United States)

    Wei, Hao; He, Yunchang; Li, Qingji; Liu, Zhiyu; Wang, Haitang

    2007-09-01

    Changjiang, the third largest runoff in the world, empties into the East China Sea from Shanghai, the fastest developing area of China. With the increasing nutrient load from the river, a severe hypoxia zone was found to about 2 * 10 4 km 2. The mechanism of hypoxia formation adjacent to the Changjiang Estuary receives more and more attention from both scientists and managers. This paper discusses the relationship between hypoxia and the water masses, primary production, particulate material transport and the density stratification in these areas according to data obtained from a cruise in September, 2003. Hypoxia is formed by organic detritus decay. The particulate organisms do not mainly come from the Changjiang river, or from the dead algal deposed locally, but from the local benthic algae or particles advected from the south. Maintenance of hypoxia is due to the large density stratification caused by the significant salinity difference between the fresh plume and salty water from Taiwan Strait. This applies also to other estuaries with large runoff and rapid economic growth drainage, such as the Pearl River. It is suggested that the hypoxic zone here is much more sensitive than that outside Mississippi River. More cruises over different weather and tide conditions are needed to prove this hypothesis. Interdisciplinary research should be further developed in the future.

  12. CO2 supersaturation and net heterotrophy in a tropical estuary (Cochin, India): Influence of anthropogenic effect - Carbon dynamics in tropical estuary

    Digital Repository Service at National Institute of Oceanography (India)

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

    higher than the net loss of dissolved and particulate organic carbon from the estuary. This imbalance is attributed to the organic inputs to the estuary through anthropogenic supplies. The bacteria-mediated mineralization of organic matter is mainly...

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

    International Nuclear Information System (INIS)

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

  14. 2012 Southwest Florida Water Management District (SWFWMD) Lidar: Lake Manatee

    Data.gov (United States)

    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...

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

    International Nuclear Information System (INIS)

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

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2004-07-01

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

  18. 75 FR 69622 - Request for Comments on the Draft Revision of the Estuary Habitat Restoration Strategy Prepared...

    Science.gov (United States)

    2010-11-15

    ...Estuary Habitat Restoration Strategy Prepared by the Estuary Habitat...Estuary Habitat Restoration Strategy.'' DATES: Comments and...analyzed sample plots using digital high-resolution imagery to...will review and refine this Strategy over time in an iterative...

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

    Data.gov (United States)

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

  20. ARMSTRONG74 - Sediment Data from Great Bay Estuary, New Hampshire

    Data.gov (United States)

    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...

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

    Digital Repository Service at National Institute of Oceanography (India)

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

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

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

    Digital Repository Service at National Institute of Oceanography (India)

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

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

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

    Directory of Open Access Journals (Sweden)

    Steve J. Jordan

    2010-12-01

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

  4. MODIS water quality algorithms for northwest Florida estuaries

    Science.gov (United States)

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

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

    Digital Repository Service at National Institute of Oceanography (India)

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

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

  6. Estimation of the Cd intake in the human dietary from the shellfish caught in the seashore of Charente-Maritime (France)

    OpenAIRE

    Miramand, Pierre; Ferchaud, René; Pijeot, Jacques; Caurant, Florence; Bustamante, Paco; Guyot, Thierry

    2002-01-01

    Gironde inputs leads to a Cd enrichment of the waters of Charente-Maritime. This presentation describes the potential risk of Cd ingestion due to the seashells by some inhabitants of the coasts of Charente-Maritime. Wild oysters analysed along the coasts showed a good correlation between Cd concentrations in their tissues and the distance from the Gironde estuary, with minimum values in the north of the department and the maximum values in the estuary where shellfish collection is by the way ...

  7. Organochlorine pesticides, polychlorinated biphenyls and trace elements in wild European sea bass (Dicentrarchus labrax) off European estuaries

    OpenAIRE

    Schnitzler, Joseph; Thomé, Jean-Pierre; Lepage, Mario; Das, Krishna, pada

    2011-01-01

    Polychlorinated biphenyls (PCBs) and organochlorine pesticides like dichloro-diphenyl-trichloroethane (DDTs), hexachlorocyclohexanes (HCHs), aldrin, dieldrin and trace elements (Cd, Cu, Se, Pb, Zn and Hg) were analysed in the muscle of European sea bass (Dicentrarchus labrax) sampled in Atlantic coastal regions near several important European river mouths (Gironde, Charente, Loire, Seine and Scheldt). High contamination levels were measured in the muscles of European sea bass sampled in the c...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-02-01

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

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

    International Nuclear Information System (INIS)

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

  10. 40 CFR 81.259 - Southwest Iowa Intrastate Air Quality Control Region.

    Science.gov (United States)

    2010-07-01

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

  11. 40 CFR 81.118 - Southwest Missouri Intrastate Air Quality Control Region.

    Science.gov (United States)

    2010-07-01

    ...Southwest Missouri Intrastate Air Quality Control Region. 81.118 Section...PURPOSES Designation of Air Quality Control Regions § 81.118 Southwest Missouri Intrastate Air Quality Control Region. The Southwest...

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

    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 can be performed via natural processes.

  14. Juvenile Salmon Usage of the Skeena River Estuary

    Science.gov (United States)

    Carr-Harris, Charmaine; Gottesfeld, Allen S.; Moore, Jonathan W.

    2015-01-01

    Migratory salmon transit estuary habitats on their way out to the ocean but this phase of their life cycle is more poorly understood than other phases. The estuaries of large river systems in particular may support many populations and several species of salmon that originate from throughout the upstream river. The Skeena River of British Columbia, Canada, is a large river system with high salmon population- and species-level diversity. The estuary of the Skeena River is under pressure from industrial development, with two gas liquefaction terminals and a potash loading facility in various stages of environmental review processes, providing motivation for understanding the usage of the estuary by juvenile salmon. We conducted a juvenile salmonid sampling program throughout the Skeena River estuary in 2007 and 2013 to investigate the spatial and temporal distribution of different species and populations of salmon. We captured six species of juvenile anadromous salmonids throughout the estuary in both years, and found that areas proposed for development support some of the highest abundances of some species of salmon. Specifically, the highest abundances of sockeye (both years), Chinook in 2007, and coho salmon in 2013 were captured in areas proposed for development. For example, juvenile sockeye salmon were 2–8 times more abundant in the proposed development areas. Genetic stock assignment demonstrated that the Chinook salmon and most of the sockeye salmon that were captured originated from throughout the Skeena watershed, while some sockeye salmon came from the Nass, Stikine, Southeast Alaska, and coastal systems on the northern and central coasts of British Columbia. These fish support extensive commercial, recreational, and First Nations fisheries throughout the Skeena River and beyond. Our results demonstrate that estuary habitats integrate species and population diversity of salmon, and that if proposed development negatively affects the salmon populations that use the estuary, then numerous fisheries would also be negatively affected. PMID:25749488

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

    Scientific Electronic Library Online (English)

    Stephen, Hosking.

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

  16. Study of the dynamic behaviour of the Sancti Petri Channel, southwest coast of Spain

    Directory of Open Access Journals (Sweden)

    2005-01-01

    Full Text Available The dynamic behaviour of the Sancti Petri tidal channel (southwest coast of Spain, which is open at both ends and connected to water bodies with different dynamic characteristics (Atlantic Ocean and Cádiz Bay, is studied herein. This singular estuary is characterized by double inflow-outflow extremes, the tide penetrating almost simultaneously through both ends with a small difference of amplitude. For this study, sea level recordings were obtained from different points throughout the channel and the corresponding harmonic constituents were determined. The results show that the phases of the semidiurnal tides increase from the mouths to a zone located in the vicinity of the channel’s halfway point, while their amplitudes increase from the Atlantic Ocean to Cádiz Bay along the channel. A one-dimensional numerical model with geometry that is representative of the channel was used to reproduce the features observed for the semidiurnal and diurnal tidal constituents. The data supplied by the model were verified with values obtained at strategically chosen sites of the inner domain. The model developed may be used for operational predictions of tides in the study area, especially for the ports of Gallineras and Sancti Petri.

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

    Digital Repository Service at National Institute of Oceanography (India)

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

    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...

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

    Digital Repository Service at National Institute of Oceanography (India)

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

    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...

  19. Silicate Abundance and its Significance in the Hooghly-Matla Estuary, India (Invited)

    Science.gov (United States)

    Ghosh, T.; Akhand, A.

    2010-12-01

    Sea water contains in suspension a wide spectrum of siliceous materials. The surface water abounds with organisms such as diatoms and radiolarians having skeletons composed of non-crystalline form of hydrated silica. A very high level of silicate (130-140 ?M) noticed in the Bay of Bengal nearer the confluence of the rivers, where nutrient levels are appreciably higher during southwest monsoon period (March-October) in contrast to other seasons (CSMCRI, 2007). The relatively high (>5 µg) silicate values at the Ganges head (Bay of Bengal) is attributable to river runoff during the same period (CSMCRI, 2007). In general, the concentration of inorganic phosphate, nitrate and silicate increased in the direction of Antarctic Sea, particularly around 40° S latitude, in the proximity of sub-tropical convergence. In comparison to Atlantic and Pacific oceans, the concentration of nutrients in the Indian Ocean is almost twice (Venkataramana, 2007). The mean value of 102.9±43.2 ?M for silicate in Hooghly estuary is found lower than worldwide average river water concentration of 147.8±93.6 ?M (Gems, 2002). Seasonal variation of river runoff of silicate shows maximum value of 12.6×109 mol during monsoon; thereafter, its value decreased to 2.54 and 1.33×109 mol during post-monsoon and pre-monsoon, respectively. The net residual flows of 4.91, 1.47 and 0.5×109 mol and the exchange flux of 6.95, 0.94 and 0.51×109 mol is found at the estuary during monsoon, post-monsoon and pre-monsoon, respectively. The annual flux of silicate out of the estuary is estimated to be 15.28×109 mol (428×103 t), about 93% of the total fluvial flux. The non-conservative flux of silicate removed from the water column is found to be 1.12 × 109 mol (31.0×103 t), which is about 5% in the global scale (0.6×106 t year-1) (Tregguer et al.,1995). Nitrate, Phosphate and Silicate, have been studied in the Hooghly-Matla estuarine complex and compared with selected previous studies. It is observed that both nitrate and phosphate concentrations remained almost stable varied (between 19.28 and 19.4?M for DIN and between 1.61and 1.99?M for DRP) during the period between 1975 and 2001, but silicate shows a distinct increasing trend from 35.6 to 102.9?M (Nandy et al., 1983; NIO, 1986; Ghosh et al., 1992). These also conforms our study, with the concentration of silicate from 19.97 µ M to 72.73 µ M during pre-monsoon and 48.26 µ M to 103.19 µ M during the monsoon in the Hooghly-Matla estuarine complex. High concentrations of biogenic silica in tidal marshes are necessary for maximum benthic diatom production which in turn helps high secondary production of commercial fish and crustaceans (Courtney, 2007). The Gross Primary Productivity is found to be increased in three stations of these estuaries (27.32±5.06 mg/m3/ hr in 1990, 33.58±14 mg/m3/ hr in 2000 and 44.36±5.91 mg/m3/ hr in 2007) (Biswas et. al., 2009), with the increasing trend of silicate within this estuarine complex. The increasing trend of total catches in the Eastern and Western Indian Ocean (FAO, 1998), of which the Bay of Bengal is an important part (Islam, 2003), justify the interrelation. Thus, these findings are ascertaining the interrelation between the increasing trend of silicate concentration with the enhanced primary productivity, which in turn increase the fish yield in the Hooghly-Matla estuarine complex on the Bay of Bengal.

  20. Monitoring Radio Frequency Interference in Southwest Virginia

    Science.gov (United States)

    Rapp, Steve

    2010-01-01

    The radio signals received from astronomical objects are extremely weak. Because of this, radio sources are easily shrouded by interference from devices such as satellites and cell phone towers. Radio astronomy is very susceptible to this radio frequency interference (RFI). Possibly even worse than complete veiling, weaker interfering signals can contaminate the data collected by radio telescopes, possibly leading astronomers to mistaken interpretations. To help promote student awareness of the connection between radio astronomy and RFI, an inquiry-based science curriculum was developed to allow high school students to determine RFI levels in their communities. The Quiet Skies Project_the result of a collaboration between the National Aeronautics and Space Administration (NASA), the National Science Foundation (NSF), and the National Radio Astronomy Observatory (NRAO)_encourages students to collect and analyze RFI data and develop conclusions as a team. Because the project focuses on electromagnetic radiation, it is appropriate for physics, physical science, chemistry, or general science classes. My class-about 50 students from 15 southwest Virginia high schools-participated in the Quiet Skies Project and were pioneers in the use of the beta version of the Quiet Skies Detector (QSD), which is used to detect RFI. Students have been involved with the project since 2005 and have collected and shared data with NRAO. In analyzing the data they have noted some trends in RFI in Southwest Virginia.

  1. Seasonal variations in abundance, biomass and grazing rates of microzooplankton in a tropical monsoonal estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Gauns, M.; Mochemadkar, S.; Patil, S.; Pratihary, A.K.; Naqvi, S.W.A.; Madhupratap, M.

    Seasonal abundance, composition and grazing rates of microzooplankton (20–200 µm) in the Zuari estuary were investigated to evaluate their importance in food web dynamics of a tropical monsoonal estuary. Average abundances of microzooplankton...

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

    Digital Repository Service at National Institute of Oceanography (India)

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

    , 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...

  3. West Coast Estuaries for Groundfish Essential Fish Habitat (EFH) Environmental Impact Statement

    Data.gov (United States)

    Pacific States Marine Fisheries Commission — These data depict the boundaries of estuaries along the West Coast of the United States. The estuary boundaries are delineated according to the U.S. Fish and...

  4. Bacterial domination over Archaea in ammonia oxidation in a monsoon-driven tropical estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Vipindas, P.V.; Anas, A.; Jasmin, C.; Lallu, K.R.; Fausia, K.H.; Balachandran, K.K.; Muraleedharan, K.R.; Nair, S.

    Autotrophic ammonia oxidizing microorganisms,which are responsible for the rate-limiting step of nitrification in most aquatic systems, have not been studied in tropical estuaries. Cochin estuary (CE) is one of the largest, productive, and monsoon-driven...

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

    Digital Repository Service at National Institute of Oceanography (India)

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

    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...

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

    Science.gov (United States)

    Musenze, Ronald S; Werner, Ursula; Grinham, Alistair; Udy, James; Yuan, Zhiguo

    2014-02-15

    Methane (CH4) and nitrous oxide (N2O) are two key greenhouse gases. Their global atmospheric budgeting is, however, flout with challenges partly due to lack of adequate field studies determining the source strengths. Knowledge and data limitations exist for subtropical and tropical regions especially in the southern latitudes. Surface water methane and nitrous oxide concentrations were measured in a subtropical estuarine system in the southern latitudes in an extensive field study from 2010 to 2012 and water-air fluxes estimated using models considering the effects of both wind and flow induced turbulence. The estuary was found to be a strong net source of both CH4 and N2O all-year-round. Dissolved N2O concentrations ranged between 9.1 ± 0.4 to 45.3 ± 1.3 nM or 135 to 435% of atmospheric saturation level, while CH4 concentrations varied between 31.1 ± 3.7 to 578.4 ± 58.8 nM or 1210 to 26,430% of atmospheric saturation level. These results compare well with measurements from tropical estuarine systems. There was strong spatial variability with both CH4 and N2O concentrations increasing upstream the estuary. Strong temporal variability was also observed but there were no clear seasonal patterns. The degree of N2O saturation significantly increased with NOx concentrations (r(2)=0.55). The estimated water-air fluxes varied between 0.1 and 3.4 mg N2O m(-2)d(-1) and 0.3 to 27.9 mg CH4 m(-2)d(-1). Total emissions (CO2-e) were N2O (64%) dominated, highlighting the need for reduced nitrogen inputs into the estuary. Choice of the model(s) for estimation of the gas transfer velocity had a big bearing on the estimated total emissions. PMID:24333994

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

    OpenAIRE

    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...

  8. An analytical solution for tidal dynamics in the Yangtze Estuary, China

    OpenAIRE

    E. F. Zhang; Savenije, H. H. G.; Chen, S. L.; X. H. Mao

    2012-01-01

    An analytical model for tidal dynamics has been applied to the Yangtze Estuary, a large branched estuary with three-order branches and four outlets to the sea. This study shows that the analytical model developed for a single-channel estuary can also accurately describe the tidal dynamics in a branched estuary, particularly in the downstream part. For given geometry, friction, and tidal amplitude at the mouth of every branch, the tidal damping/amplification, the phase lag, the wave celer...

  9. Sediment balance of intertidal mudflats in a macrotidal estuary

    Science.gov (United States)

    lafite, R.; Deloffre, J.; Lemoine, M.

    2012-12-01

    Intertidal area contributes widely to fine-grained sediment balance in estuarine environments. Their sedimentary dynamics is controlled by several forcing parameters including tidal range, river flow and swell, affected by human activities such as dredging, construction or vessels traffic leading to modify sediment transport pattern. Although the estuarine hydrodynamics is well documented, the link between forcing parameters and these sedimentary processes is weakly understood. One of the main reasons is the difficulty to integrate spatial (from the fluvial to the estuary mouth) and temporal (from swell in seconds to pluriannual river flow variability) patterns. This study achieved on intertidal mudflats distributed along the macrotidal Seine estuary (France) aims (i) to quantify the impact of forcing parameters on each intertidal area respect to its longitudinal position in the estuarine system and (ii) to assess the fine-grained sediment budget at estuarine scale. The Seine estuary is a macrotidal estuary developed over 160 km up the upstream limit of tidal wave penetration. With an average river flow of 450m3.s-1, 80% of the Suspended Particles Matter (SPM) annual flux is discharged during the flood period. In the downstream part, the Seine estuary Turbidity Maximum (TM) is the SPM stock located near the mouth. During their transfer toward the sea, the fine particles can be trapped in (i) the intertidal mudflats; preferential areas characterized by low hydrodynamics and generally sheltered of the tidal dominant flow, the main tidal current the Seine River and (ii) the TM. The Seine estuary is an anthropic estuary in order to secure navigation: one consequence of these developments is the tidal bore disappearance. Along the macrotidal Seine estuary hydrodynamics features and sedimentary fluxes were followed during at least 1 year using respectively Acoustic Doppler Velocimeter, Optical BackScatter and altimeter. Results in the fluvial estuary enhance the role of hydrological cycle that lead to (i) an increased mean water level and (ii) provide SPM from the continental area. This feature leads to significant accretion over intertidal area. In the middle and marine estuary the TM is the main SPM supplier. In these parts of the estuary deposition over these intertidal area is driven by (i) tidal cycle in particular fortnightly cycle link to maximum TM resuspension during (strongest) spring tide and (ii) TM location controlled by river inflow that varies following an annual and inter-annual variability. Outside sedimentation period, the erosion is driven by the combination of (i) progressive erosion driven by fortnightly cycle and (ii) sudden erosion controlled either by wave or boat generated waves respectively at the mouth and in the middle/upper estuary. This last is reinforced by the rheological characteristics of deposit that correspond to fluid/low consolidated mud. During most of the year, the Seine estuary mudflats record an erosion pattern. Significant and intensive sedimentation only occurs few days per year. This pattern is linked to highly variable hydrodynamics conditions (bottom shear stress ranging from 0.5 to 5 N.m-2) that control the sediment supply availability. In this infilling macrotidal anthropized system mudflats are close to equilibrium with an annual rate ranging between +/- 5cm.yrs-1: they act as temporal storage area of fined-grained sediments.

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

    Digital Repository Service at National Institute of Oceanography (India)

    Sarma, V.V.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. Effect of freshwater influx on phytoplankton in the Mandovi estuary (Goa, India) during monsoon season: Chemotaxonomy

    Digital Repository Service at National Institute of Oceanography (India)

    Parab, S.G.; Matondkar, S.G.P.; Gomes, H.R.; Goes, J.I.

    The Mandovi estuary is a prominent water body that runs along the west coast of India. It forms an estuarine network with the adjacent Zuari estuary, connected via the Cumbharjua canal. The physico-chemical conditions seen in the Mandovi estuary...

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

    Digital Repository Service at National Institute of Oceanography (India)

    Shetye, S.R.; Vijith, V.

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

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

    International Nuclear Information System (INIS)

    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)

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

    Science.gov (United States)

    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.

  15. Erosion Levels in Santander Bay Estuary (Spain)

    International Nuclear Information System (INIS)

    Full Text: Soil erosion was evaluated in several points from the Santander bay proximity in the north of Spain. The used method is based on the measurement of the radioactive isotope Cs-137 present in the soil. The rates and spatial extent of Cs-137 loss can be established and thus soil movement budgets are easily estimated. Core samples were collected in 18 points and sectioned at 5 cm depth intervals. Samples of soil were air dried and passed through a 2 mm sieve. Radionuclide activities were measured using a high resolution, low background, Ge HP gamma ray detector. This soil movements are estimated by comparing the activity of Cs-137 of a soil point with the activity of Cs-137 in sites assumed to be un eroded. The obtained results show high and regular soil erosion levels for the most part of studied estuary. The last can be explained by the intensive building construction taken place in the area in the last few years. On the other hand, the Ra-226, Th-232 and K-40 concentration levels in soil allow the correlation with its concentration levels in bay sediments, to establish a transport scheme of the eroded material

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Science.gov (United States)

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

    2013-05-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-02-05

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

  3. Benthic fauna of southwest and southeast coasts of India

    Digital Repository Service at National Institute of Oceanography (India)

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

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

    Data.gov (United States)

    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...

  5. 7 CFR 1126.2 - Southwest marketing area.

    Science.gov (United States)

    2010-01-01

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

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

    Data.gov (United States)

    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,...

  7. Shallow-Water Benthic Habitats of Southwest Puerto Rico

    Data.gov (United States)

    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...

  8. 75 FR 15411 - Southwest Montana Resource Advisory Committee Meeting

    Science.gov (United States)

    2010-03-29

    ...Act (Pub. L. 92-463) and under the Secure Rural Schools and Community Self-Determination Act of 2000...reauthorized legislation; (2) Purpose of the Secure Rural Schools Act; (3) Roles and responsibilities of the Southwest...

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

    Data.gov (United States)

    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...

  10. 75 FR 61790 - Capital Southwest Corporation; Notice of Application

    Science.gov (United States)

    2010-10-06

    ...proposed rule); Executive Compensation and Related...as amended by Executive Compensation Disclosure...have a dilutive effect on the shareholders...financial services firms for talented...Southwest's performance and...

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

    Science.gov (United States)

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

    2008-01-01

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

  12. Southwest Region Experiment Station - Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Rosenthal, A

    2011-08-19

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

  13. The Quaternary coversands of southwest France

    Science.gov (United States)

    Sitzia, Luca; Bertran, Pascal; Bahain, Jean-Jacques; Bateman, Mark D.; Hernandez, Marion; Garon, Henri; de Lafontaine, Guillaume; Mercier, Norbert; Leroyer, Chantal; Queffelec, Alain; Voinchet, Pierre

    2015-09-01

    Detailed stratigraphic analysis and numerical dating (OSL, IRSL, ESR, 14C) of Pleistocene coversands in southwest France enable the construction of a renewed chronostratigraphic framework for sand deposition. The chronological data obtained from sandsheet units testify to the development of transgressive dunefields since at least the Middle Pleistocene (MIS 10). Three main phases of accumulation occurred during the Last Glacial. The oldest one (64-42 ka) is associated with wet sandsheet facies, histic horizons and zibar-type dune fields, which reflect deposition in a context strongly influenced by the groundwater table. The Late Pleniglacial (24-14 ka) corresponds to the main phase of coversand extension in a drier context. Silty gley horizons suggest, however, local interruptions of sand drifting during GS 2.1. Lateglacial stabilization of the coversands may not have occurred before GI-1c (Allerød), which was typified by the development of cumulic arenosols. These were covered by parabolic dunes during the Younger Dryas. The variations in extent of the emerged continental shelf during the glacial-interglacial cycles may explain the uneven geographical distribution of sand deposition through time. Because of coastline retreat up to 100 km north of 45°N during the LGM lowstand, the coversands were unable to reach the northern part of the basin. Comparison with other European regions highlights stronger affinities of the French record with Portugal than with the Netherlands and Great Britain, probably because of reduced influence of permafrost.

  14. An assessment of tidal energy potential. The Lima estuary

    Energy Technology Data Exchange (ETDEWEB)

    Trigo-Teixeira, A. [Department of Civil Engineering and Architecture, Instituto Superior Tecnico, Lisbon Technical University, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Rebordao, I. [WW Consulting Engineers, Laveiras, Caxias 2760-032 (Portugal)

    2009-07-01

    A hydrodynamic model was set up for the Lima estuary (Portugal) and a preliminary assessment of the strength of tidal currents to produce tidal energy was made. To calibrate the model results were compared with measured data, and the model tuned to reproduce water levels and currents in several locations within the estuary. The data was acquired with ADCPs, during a field campaign that was planed to cover a spring-neap tide cycle, in October 2006. The Advanced Circulation Model - ADCIRC was forced with the most important harmonic constituents present in the ocean tide signal. Upstream, in the river boundary, the discharge was taken from hydrographs. The wetting and drying tool was also applied and a detailed bathymetry was considered, since there are areas in the domain where salt marshes occur, drying out at low tide. The tidal currents potential were assessed for a scenario of tidal forcing only, without any river discharge. The lower estuary is occupied by the port infrastructure and navigation channels which conflicts with any kind of equipment installation. Values of the currents and water depths given by the model indicate that some places in the main channel of the middle estuary, might be interesting to install micro turbines in the future, depending on the evolution of the requirements of this technology.

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

    Digital Repository Service at National Institute of Oceanography (India)

    Sharma, P.; Zingde, M.D.

    Behaviour od dissolved Al, Si and Fe in high energy and well-mixed Tapi Estuary in Maharashtra, India was studied under varied tidal cycles. The observed trend of variation in concentration of dissolved Al has been explained in terms of release from...

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

    International Nuclear Information System (INIS)

    Observations of salinity, temperature, suspended sediment concentration (SSC) and tidal current velocity were made in the lower and along the longitudinal axis 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)

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

    Digital Repository Service at National Institute of Oceanography (India)

    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...

  18. The tidal asymmetries and residual flows in Ems Estuary

    Science.gov (United States)

    Pein, Johannes Ulrich; Stanev, Emil Vassilev; Zhang, Yinglong Joseph

    2014-12-01

    A 3D unstructured-grid numerical model of the Ems Estuary is presented. The simulated hydrodynamics are compared against tidal gauge data and observations from research cruises. A comparison with an idealized test reveals the capability of the model to reproduce the secondary circulation patterns known from theoretical results. The simulations prove to be accurate and realistic, confirming and extending findings from earlier observations and modeling studies. The basic characteristics of dominant physical processes in the estuary such as tidal amplification, tidal damping, overtide generation, baroclinicity and internal mixing asymmetry are quantified. The model demonstrates an overall dominance of the flood currents in most of the studied area. However, the hypsometric control in the vicinity of Dollart Bay reverses this asymmetry, with the ebb currents stronger than the flood ones. Small-scale bathymetric characteristics and baroclinicity result in a very complex interplay between dominant physical mechanisms in different parts of the tidal channels and over the tidal flats. Residual flow reveals a clear overturning circulation in some parts of the estuary which is related to a mixing asymmetry between flood and ebb currents. We demonstrate that while areas close to the tidal river exhibit overall similarity with density controlled estuarine conditions, in large areas of the outer estuary barotropic forcing and complex bathymetry together with the density distribution affect substantially the horizontal circulation.

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

    Digital Repository Service at National Institute of Oceanography (India)

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

    . The reduced water discharge, during the peak discharge period, slowed the flushing of the estuary from 1.2 days to 6.3 days, respectively. The consequent increase in stability of water column and reduced suspended material load gave rise to intense...

  20. Polychlorinated biphenyls in the Brisbane River Estuary, Australia

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, G.R.; Connell, D.W.

    1980-12-01

    The concentrations of PCB's in water, sediment, fish, crustacea, molluscs, and polychaetes from the Brisbane River estuary in Australia were determined. Levels were comparable to other similar situations elsewhere. No relationship was found between trophic class and PCB concentration. (12 references, 1 table)

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

    Digital Repository Service at National Institute of Oceanography (India)

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

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

  2. Do Sturgeon limit burrowing shrimp populations in Pacific Northwest estuaries?

    Science.gov (United States)

    Green sturgeon (Acipenser medirostris) and white sturgeon (Acipenser transmontanus) are common seasonal inhabitants of coastal estuaries from California USA to British Columbia, Canada. Both species are anadromous spending significant portions of their lives at sea and in their natal streams, but t...

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

    Digital Repository Service at National Institute of Oceanography (India)

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

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

  4. The dynamics of a frictionally-dominated Amazonian estuary

    Scientific Electronic Library Online (English)

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

    2012-09-01

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

  5. The dynamics of a frictionally-dominated Amazonian estuary

    Directory of Open Access Journals (Sweden)

    Nils Edvin Asp

    2012-09-01

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

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

    International Nuclear Information System (INIS)

    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 that currently causes significant water quality issues, Cu removal due to burial of suspended sediment in realigned areas translates to a value of approximately Pounds 1000 a-1 (avoided clean up costs). Although this is not formally included in the CBA it illustrates another likely positive economic outcome of managed realignment. Although we focus on the Humber, the history of reclamation and its biogeochemistry is common to many estuaries in northern Europe

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

    Directory of Open Access Journals (Sweden)

    V. R. Shevchenko

    2005-01-01

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

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

    Science.gov (United States)

    Yu, Yingying; Zhang, Hong; Lemckert, Charles

    2014-11-01

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

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

    Science.gov (United States)

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

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

    Science.gov (United States)

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

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

    Directory of Open Access Journals (Sweden)

    Carlos Augusto França Schettini

    2010-03-01

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

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

    Scientific Electronic Library Online (English)

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

    2010-03-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-02-20

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

  14. 76 FR 59682 - Desert Southwest Customer Service Region-Western Area Lower Colorado Balancing Authority-Rate...

    Science.gov (United States)

    2011-09-27

    ...ENERGY Western Area Power Administration Desert Southwest Customer Service Region...Area Power Administration's (Western) Desert Southwest Customer Service Region (DSWR...CONTACT: Mr. Jack Murray, Rates Manager, Desert Southwest Customer Service Region,...

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

    Science.gov (United States)

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

    2014-12-01

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

  16. Influence of physicochemical and nutritional factors on bacterial diversity in mangrove sediments along the southwest coast of Tamilnadu, India.

    Science.gov (United States)

    Prakash, S; Ramasubburayan, R; Iyapparaj, P; Ahila, N K; Sri Ramkumar, V; Palavesam, A; Immanuel, G; Kannapiran, E

    2015-09-01

    The present study was undertaken to investigate the diversity of mangrove-associated bacterial genera at Manakudy estuary, Southwest coast of India. The root and rhizosphere sediments of both mangrove and their associated plants were collected from chosen area. Results inferred that the maximum nutrients, THB density, and diversity indices were recorded in rhizosphere and root sample of Avicennia officinalis. Altogether, 258 bacterial strains were isolated from the chosen mangrove samples and screened for nitrogen fixing and phosphate solubilizing ability. Screened result inferred that, 36.43 % isolates had nitrogen fixing and 29.45 % isolates had phosphate solubilizing ability. Here, the genus Bacillus spp. (21.71 %) was the most dominant genera. The bacterial diversity indices, i.e., univariate analysis showed remarkable variation between the chosen samples; however, maximum diversity indices was registered by rhizosphere and root sample of A. officinalis. The 95 % confidence interval and ellipse showed that samples were well mendacious within AvTD and VarTD. Likewise, the multivariate analysis like similarity percentage was good discriminator from 16.64 to 100 % by Bray-Curtis dissimilarity. The prinicipal component analysis (PCA) showed marked variation between the tested bacterial communities. Cluster analysis and non-metric multi-dimensional scaling (MDS) were grouped by Bray-Curtis similarity index which strongly evidence that the rhizosphere and root samples of A. officinalis were highly diversified in the study area. PMID:26255268

  17. Seasonal Behaviour of a Shallow Estuary of Lower Cauvery Basin, India

    Directory of Open Access Journals (Sweden)

    Priya K L

    2012-10-01

    Full Text Available The effect of bifurcation at the estuary mouth was studied on the measurements of salinity, current and tidal depth in a shallow estuary during spring and neap tides of two different seasons. There was a considerable variation of salinity at the observed stations during the seasons. At the shallowest location of the estuary, salinity, as high as 37 ppt, was observed during the period of zero fresh water discharge. The flushing time of the estuary was higher at its western side compared to the eastern one. The diffusion coefficient was reached by using an advection-diffusion equation. The estuary was classified using a circulation/stratification diagram. Well mixed conditions persisted during pre monsoon and post monsoon in the Muthupet estuary.DOI: http://dx.doi.org/10.5755/j01.erem.61.3.2041

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

    OpenAIRE

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

    2013-01-01

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

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

    OpenAIRE

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

    2012-01-01

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

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

    OpenAIRE

    van der Ham, Joris L.; de Mutsert, Kim

    2014-01-01

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

  1. Key discursive themes for the environmental governance of the Vouga Estuary (Ria de Aveiro)

    OpenAIRE

    Sumares, David; Fidélis, Teresa

    2013-01-01

    Over the past decades, at the same time that traditional activities declined, the Ria de Aveiro (the estuary of the river Vouga) has suffered strong development pressures (urban, agricultural and industrial), which have caused severe environmental problems such as water pollution, eutrophication, habitat destruction, among others. In particular, changes in the estuary’s hydrodynamics are being increasingly seen as especially damaging to the Ria’s ecosystems, protected under the Natura 2000...

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

    Data.gov (United States)

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

    Data.gov (United States)

    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...

  4. 2004 Southwest Florida Water Management District (SWFWMD) Lidar: Lake Hancock District

    Data.gov (United States)

    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. 78 FR 54905 - Endangered and Threatened Wildlife and Plants; Southwest Alaska Distinct Population Segment of...

    Science.gov (United States)

    2013-09-06

    ...Southwest Alaska Distinct Population Segment of the Northern...Availability of Recovery Plan AGENCY: Fish and Wildlife Service...availability of our recovery plan for the southwest Alaska Distinct Population Segment (DPS)...

  6. Seasonal Behaviour of a Shallow Estuary of Lower Cauvery Basin, India

    OpenAIRE

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

    2012-01-01

    The effect of bifurcation at the estuary mouth was studied on the measurements of salinity, current and tidal depth in a shallow estuary during spring and neap tides of two different seasons. There was a considerable variation of salinity at the observed stations during the seasons. At the shallowest location of the estuary, salinity, as high as 37 ppt, was observed during the period of zero fresh water discharge. The flushing time of the estuary was higher at its western side compared to the...

  7. Circulation and physical processes within the San Gabriel River Estuary during summer 2005

    Science.gov (United States)

    Rosenberger, Kurt J.; Xu, Jingping; Stein, Eric D.; Noble, Marlene A.; Gartner, Anne L.

    2007-01-01

    The Southern California Coastal Water Research Project (SCCWRP) is developing a hydrodynamic model of the SGR estuary, which is part of the comprehensive water-quality model of the SGR estuary and watershed investigated by SCCWRP and other local agencies. The hydrodynamic model will help understanding of 1) the exchange processes between the estuary and coastal ocean; 2) the circulation patterns in the estuary; 3) upstream natural runoff and the cooling discharge from PGS. Like all models, the SGR hydrodynamic model is only useful after it is fully calibrated and validated. In May 2005, SCCWRP requested the assistance of the U.S. geological Survey (USGS) Coastal and Marine Geology team (CMG) in collecting data on the hydrodynamic conditions in the estuary during the summer dry season. The summer was chosen for field data collection as this was assumed to be the season with the greatest potential for chronic degraded water quality due to low river flow and high thermal stratification within the estuary (due to both higher average air temperature and PGS output). Water quality can be degraded in winter as well, when higher river discharge events bring large volumes of water from the Los Angeles basin into the estuary. The objectives of this project were to 1) collect hydrodynamic data along the SGR estuary; 2) study exchange processes within the estuary through analysis of the hydrodynamic data; and 3) provide field data for model calibration and validation. As the data only exist for the summer season, the results herein only apply to summer conditions.

  8. Effects of winds on stratification and circulation in a partially mixed estuary

    Science.gov (United States)

    Li, Yun; Li, Ming

    2011-12-01

    Numerical experiments are conducted to investigate how axial winds affect stratification and circulation in the partially mixed estuary of Chesapeake Bay. In the absence of rotational effects, stratification in the estuary decreases following both down-estuary and up-estuary winds, but stratification experiences larger reduction and takes longer to recover under up-estuary winds. In the presence of rotational effects, wind-driven lateral circulations cause the lateral straining of density field and weaken the shear in the along-channel flows. Under the down-estuary winds, a counterclockwise lateral circulation steepens isopycnals in the cross-channel sections, while the Coriolis force acting on it decelerates the downwind current in the surface layer and the upwind-directed current in the bottom layer. Under the up-estuary winds, a clockwise lateral circulation flattens isopycnals in the cross-channel sections and reduces the shear between the surface and bottom currents. Hence, in the presence of rotational effects, the lateral straining offsets the effects of longitudinal straining such that the asymmetry in stratification reduction is significantly reduced between the down-estuary and up-estuary winds. Regime diagrams based on Wedderburn (W) and Kelvin (Ke) numbers are constructed to summarize the net effects of winds on estuarine stratification during both wind perturbation and postwind adjustment periods.

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    OpenAIRE

    Hyun Jung Cho

    2007-01-01

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

  12. Subtidal variability in water levels inside a subtropical estuary

    Science.gov (United States)

    Henrie, Krista; Valle-Levinson, Arnoldo

    2014-11-01

    Year-long time series of water level are analyzed at five locations along the St. Johns River Estuary, Florida, to investigate propagation of subtidal pulses. Hilbert-transformed Empirical Orthogonal Functions (HEOFs) are obtained after a dominant seasonal signal is extracted from the data. These functions provide information on spatial structure and propagation phase of subtidal water level pulses. The first HEOF mode explains 96% of the subtidal variability and features an unusual spatial structure: amplitude attenuation (averaging 1 mm/km) to 55 km upstream, slight amplification (0.16 mm/km) over the middle 70 km, and attenuation (2.3 mm/km) over the final 18 km of the estuary. The phase suggests a shift from progressive to quasi-standing wave behavior at 55 km from the estuary mouth. Additionally, local minima in the phase suggest two sources of subtidal forcing: the coastal ocean and the upstream end. An analytical model describing the evolution of long waves through a channel with frictional damping is fit to the amplitude of HEOF mode 1. Solutions are obtained as a function of two parameters: the nondimensional length of the basin, ?, and the nondimensional frictional depth, ?. Values of ? between 0.55 and 0.67 and ? between 1.45 and 1.7 provide the best fit with the HEOF results (1% error or less). These values indicate a highly frictional environment in which the average subtidal wavelength is 10 times the basin length. Subtidal pulses in this estuary, therefore, behave as damped waves that can be represented with idealized models.

  13. Summary of implementation and demonstration projects in bays and estuaries

    International Nuclear Information System (INIS)

    The projects investigated include demonstration projects as well as unique programmatic initiatives of 15 bays and estuaries and are divided into 11 separate project categories: Boat and Marine Wastes; Contaminated Sediments; Land Use and Development Controls; Local Government and Community Involvement; Nutrient Loading; On-site Disposal Systems; Public Outreach and Education; Shellfish Bed Protection and Restoration; Stormwater Controls; Toxic Waste Reduction; Wetlands/Habitat Protection and Restoration

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

    Science.gov (United States)

    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.

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

    OpenAIRE

    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...

  16. Bedforms and Evolution of Tropical Estuaries: Examples from Northeastern Brazil

    Science.gov (United States)

    Vital, H.; Soares, C.; Rocha, G.; Pereira, T.; Eichler, P.

    2012-12-01

    This paper intends to show the geomorphological and sedimentary responses of tropical estuaries to meteorological and oceanographic forcing. The study area is located on the coastal zone of Rio Grande do Norte State, northeastern Brazil. This coast is under natural influence of waves and tides with a semidiurnal mesotidal regime and anthropogenic influence (urbanization, oil and salt industries, shrimp farms, and tourism). An operational methodology was developed using collection and analysis of an integrated dataset (comprising remote sensing, oceanographic, hy-droacoustic, and sedimentologic data). All data were integrated through a geographical infor-mation system database. The imaging of subaqueous features allowed the identification of differ-ent bedforms as well as submerged rocky outcrops. Four main groups of bedforms were identi-fied: 2D and 3D large dunes, ripples and flat bottom, and rocky outcrops as well. Rocky outcrops were correlated to Barreiras Formation and beachrocks. The estuarine channel is filled by Holocene sandy- to silt sediments, with sandy sediments in the main channel ranging from well-selected to selected grains, and silty sediments in the river margins. The integration and analysis of currents velocity and other physical parameters with bedforms characterization and different sedimentary textures in the study area allows a better knowledge of the active sedimentary processes, which are responsible for the formation of morphologic features of these estuaries. The evolution of estuary settings, led by the postglacial sea-level rise, is recorded in the subsurface an present-day riverbed. These results contribute to a better understanding of tropical estuaries.; Location of the study area

  17. Hidrodynamics influence assessment on Mondego Estuary eutrophication process

    OpenAIRE

    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...

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

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, T.V.N.

    -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... to be the major source of this mixing en- ergy. The degree of stratification can be seen as a dynamic balance between buoyancy input, which will tend to increase stratification, and turbulent kinetic energy input, which will tend to break it down. The biological...

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

    OpenAIRE

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

    2000-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-05-01

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

  1. An ecohydrology model of the Guadiana Estuary (South Portugal)

    Science.gov (United States)

    Wolanski, Eric; Chicharo, Luís; Chicharo, M. Alexandra; Morais, Pedro

    2006-10-01

    A 1-D ecohydrology model is proposed that integrates physical, chemical and biological processes in the Guadiana Estuary during low flow conditions and that predicts the ecosystem health as determined by the following variables: river discharge, nutrients, suspended particulate matter, phytoplankton, zooplankton, bivalves, zooplanktivorous fish and carnivorous/omnivorous fish. Low flow conditions prevail now that the Alqueva dam has been constructed. The ecological sub-model is based on the non-linear Lotka-Volterra equation. The model is successful in capturing the observations of along-river changes in these variables. It suggests that both bottom-up and top-down ecological processes control the Guadiana Estuary ecosystem health. A number of sensitivity tests show that the model is robust and can be used to predict - within likely error bounds provided by the sensitivity tests - the consequences on the estuary ecosystem health of human activities throughout the river catchment, such as the irrigation farming downstream of the Alqueva dam, reclamation of the salt marshes by urban developments, and flow regulation by the Alqueva dam. The model suggests that the estuarine ecosystem health requires transient river floods and is compromised by flow regulation by the Alqueva dam. Remedial measures are thus necessary.

  2. Infralittoral fish assemblages in the Zrmanja estuary, Adriatic Sea

    Directory of Open Access Journals (Sweden)

    Branimir BAŽDARI?

    2007-06-01

    Full Text Available The infralittoral fish assemblage was investigated inside the temperate Zrmanja river estuary, Adriatic Sea. The specimens were caught using a beach seine at three stations and four times over the year. A total of 10 035 individuals, belonging to 47 species and to 17 families were represented in the catch, out of these Atherina boyeri (60.3%, Symphodus ocellatus (14.4% and Pomatoschistus marmoratus (7.5% were most abundant, comprising 82.2% of the total catch. Marine and estuarine species represented 89.6 and 10.4%, respectively, while freshwater species were not observed in samples. Differences in fish assemblages were observed with respect to sampling dates and stations mostly due to different temporal and spatial distributions of juvenile fish settlers. Juveniles of open sea spawners (L. mormyrus, P. erythrinus were found with increased distance from the river mouth. As they progressively grow, they disperse throughout the estuary. Juveniles of resident species (Pomatoschistus sp. stayed closer to the river mouth. Permanent estuary residents comprised 11 species, 33 species were opportunists and the remaining 3 were transients. The data thus show that even in small temperate estuariesthe characteristics of river inflow have the potential to alter spatio-temporal patterns in infralittoral fish assemblages.

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

    Data.gov (United States)

    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...

  4. Spartina maritima influence on the dynamics of the phosphorus sedimentary cycle in a warm temperate estuary (Mondego estuary, Portugal)

    OpenAIRE

    Lillebø, Ana; Coelho, J.; Flindt, M; Jensen, H.; Marques, J; Pedersen, C; Pardal, M.

    2007-01-01

    Abstract During the last decades the Mondego estuary has been under severe ecological stress mainly caused by eutrophication. In this salt march system, Spartina maritima covers about 10.5 ha of the intertidal areas. The objective of the present study was to evaluate the effect of Spartina maritima marshes on the dynamics of phosphorus (P) binding in the surface sediment. We compare phosphate and oxygen fluxes, P-adsorption capacity, phosphate concentrations and total amount, and the extract...

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

    Science.gov (United States)

    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 ?15N 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 contribution from a region where human influences are still at a relatively low level, and hence will add to existing information from cold temperate, mainly forested watershed-estuary environments.

  6. Globalizing Higher Education Access in South-West Nigeria

    Science.gov (United States)

    Olayiwola, Mohammed Mubashiru; Kolawole, Oladipupo Fatai; Moyosore, Onabanjo Florence

    2013-01-01

    Education is central to national interest and cannot be solely determined by market forces. Thus, the role of the state in making education policy and funding education to embrace access cannot be overemphasized. The influence of globalization on Higher Education access in Southwest Nigeria as it affects policy making was investigated through the…

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

    LENUS (Irish Health Repository)

    Kennedy, M P

    2012-02-03

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

  8. ECOLOGICAL CONDITION OF THE U.S. MID-ATLANTIC ESTUARIES: THE MID-ATLANTIC INTEGRATED ASSESSMENT (MAIA)

    Science.gov (United States)

    The Mid-Atlantic Integrated Assessment (MAIA-Estuaries) evaluated ecological conditions in US Mid-Atlantic estuaries during the summers of 1997 and 1998. Over 800 probability-based stations were monitored in four main estuarine systems?Chesapeake Bay, the Delaware Estuary, Maryla...

  9. Distribution and seasonal variation of trace metals in surface sediments of the Mandovi estuary, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Alagarsamy, R.

    different areas of the estuary indicates that there is a detectable anthropogenic input to the Mandovi estuary. The enrichment of Fe and Mn reflects the intensity of anthropogenic inputs related to iron ore processing in the upstream region of the estuary...

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

    Energy Technology Data Exchange (ETDEWEB)

    1991-12-31

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

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

    International Nuclear Information System (INIS)

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

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

    Directory of Open Access Journals (Sweden)

    A. D. Nguyen

    2006-01-01

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

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

    Science.gov (United States)

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

  14. 76 FR 14924 - Takes of Marine Mammals Incidental to Specified Activities; Russian River Estuary Management...

    Science.gov (United States)

    2011-03-18

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

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

    Digital Repository Service at National Institute of Oceanography (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...

  16. Impacts of dredging on dry season suspended sediment concentration in the Brisbane River estuary, Queensland, Australia

    Science.gov (United States)

    Hossain, Shahadat; Eyre, Bradley D.; McKee, Lester J.

    2004-11-01

    Extensive dredging in the Brisbane River estuary since European settlement has significantly altered estuarine hydrological and sediment transport processes. A large tidal ingress resulting from extensive dredging in the lower Brisbane River estuary and gravel extraction including point and non-point inputs in the upper estuary are currently maintaining two distinct turbidity maximum zones within the estuary: at the mouth (100-150 mg/L) and at about 60 km upstream (>300 mg/L). In addition, extensive dredging has also increased Brisbane estuary dry season flushing time significantly (>300 days) and as a consequence the estuary is currently unable to flush any point and non-point inputs beyond 35 km upstream from its mouth during the entire dry season resulting in a very high suspended sediment (SS) concentration all along the estuary except an area between two turbidity zones. In general, this work shows strong ramifications of dredging estuaries in other parts of the world, which are currently facing increased pressure from urbanisation and navigation requirements in conjunction with industrial developments.

  17. 78 FR 68995 - Safety Zone: Vessel Removal From the Oakland Estuary, Alameda, CA

    Science.gov (United States)

    2013-11-18

    ...: Table of Acronyms DHS Department of Homeland Security FR Federal Register NPRM Notice of Proposed... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone: Vessel Removal From the Oakland Estuary... Street Bridge in Alameda, CA in support of the Oakland Estuary Closure for the Vessel Removal Project...

  18. Mapping ecosystem services in a Great Lakes estuary supports local decision-making

    Science.gov (United States)

    Estuaries of the Laurentian Great Lakes provide a concentrated supply of ecosystem goods and services from which humans benefit. As long-term centers of human activity, most estuaries of the Great Lakes and have a legacy of chemical contamination, degraded habitats, and non-point...

  19. EFFECTS OF EROSION AND MACROALGAE ON INTERTIDAL EELGRASS (ZOSTERA MARINA) IN A NORTHEASTERN PACIFIC ESTUARY (USA)

    Science.gov (United States)

    Eelgrass (Zostera marina) in open-coast northeastern Pacific estuaries is primarily intertidal, yet little research has been done on the natural factors controlling its upper intertidal growth limits. This two-year study in the Yaquina Estuary (Newport, Oregon, USA) evaluated the...

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

    Digital Repository Service at National Institute of Oceanography (India)

    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...

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

    Science.gov (United States)

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

    2015-01-01

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

  2. Dramatic Demand Reduction In The Desert Southwest

    Energy Technology Data Exchange (ETDEWEB)

    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 adjusting settings. In a sense the customer can choose between greater comfort and greater money savings during demand response circumstances. Finally a battery application was to be considered. Initially it was thought that a large battery (probably a sodium-sulfur type) would be installed. However, after the contract was awarded, it was determined that a single, centrally-located battery system would not be appropriate for many reasons, including that with the build out plan there would not be any location to put it. The price had risen substantially since the budget for the project was put together. Also, that type of battery has to be kept hot all the time, but its use was only sought for summer operation. Hence, individual house batteries would be used, and these are discussed at the end of this report. Many aspects of the energy use for climate control in selected houses were monitored before residents moved in. This was done both to understand the magnitude of the energy flows but also to have data that could be compared to the computer simulations. The latter would be used to evaluate various aspects of our plan. It was found that good agreement existed between actual energy use and computed energy use. Hence, various studies were performed via simulations. Performance simulations showed the impact on peak energy usage between a code built house of same size and shape compared to the Villa Trieste homes with and without the PV arrays on the latter. Computations were also used to understand the effect of varying orientations of the houses in this typical housing development, including the effect of PV electrical generation. Energy conservation features of the Villa Trieste homes decreased the energy use during peak times (as well as all others), but the resulting decreased peak occurred at about the same time as the code-built houses. Consideration of the PV generation decreases the grid energy use further during daylight hours, but did not extend long enough many days to decrease the peak. Hence, a demand response approach, as planned, was needed. With p

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

    Science.gov (United States)

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

    2007-01-01

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

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

    DEFF Research Database (Denmark)

    Lund-Hansen, Lars Chresten; Nhu Hai, Doan

    2010-01-01

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

  5. A framework for investigating general patterns of benthic ?-diversity along estuaries

    Science.gov (United States)

    Barros, Francisco; Blanchet, Hugues; Hammerstrom, Kamille; Sauriau, Pierre-Guy; Oliver, John

    2014-08-01

    The description of major patterns in beta (?) diversity is important in order to understand changes in community composition and/or richness at different spatial and temporal scales, and can interrogate processes driving species distribution and community dynamics. Human impacts have pushed many estuarine systems far from their historical baseline of rich, diverse, and productive ecosystems. Despite the ecological and social importance of estuaries, there has not yet been an attempt to investigate patterns of ?-diversity and its partitioning along estuarine systems of different continents. We aimed to evaluate if benthic assemblages would show higher turnover than nestedness in tropical than in temperate systems, if well-known impacted estuaries would show greater nestedness than less polluted systems, and to propose a conceptual framework for studying benthic macrofauna beta diversity along estuaries. We analyzed subtidal benthic macrofaunal data from estuaries in Brazil, USA and France. We estimated alpha (?), beta (?) and gamma (?) diversity for each sampling time in each system, investigated patterns of ? -diversity as multivariate dispersion and the partitioning (nestedness and replacement) of ?-diversity along each estuary. There was a decrease in the ?-diversity along marine to freshwater conditions at most of the estuaries and sampling dates. Beta diversity as multivariate dispersion showed high variability. Most of the estuaries showed a greater proportion of the ?-diversity driven by replacement than nestedness. We suggest a conceptual framework for estuaries where relatively pristine estuaries would have their ?-diversity mostly driven by replacement while impacted estuaries subjected to several anthropogenic stressors would show total nestedness or total replacement, depending on the stress.

  6. A Suspended Sediment Budget for the Modified Subtropical Brisbane River Estuary, Australia

    Science.gov (United States)

    Eyre, B.; Hossain, S.; McKee, L.

    1998-10-01

    Annual suspended sediment budgets, for an average flow year and a wet year, were constructed for the sub-tropical Brisbane River estuary. The input of marine sediment from Moreton Bay is the dominant source of suspended sediment (about 456 000 t) to the Brisbane River estuary during an average flow year, contributing more than 1·5 times the sediment delivered from the catchment (about 178 000 t) and urban areas (about 112 000 t) combined. As the volume of water discharged during floods increases, the sediment retention efficiency of the Brisbane River estuary decreases rapidly due to the flushing of sediment through its mouth. As such, although the input of sediment from the catchment increased three-fold (600 000 t) during 1996 associated with a 20 year return period flood, marine sediment was still the dominant source of sediment deposited in the estuary because 77% of the fluvial sediment was exported to Moreton Bay. Dredging has increased the sediment trapping capacity of the estuary with more than a two-fold increase in the flood water volume needed (about 2000×10 6 m 3) to flush the estuary fresh at the mouth compared to pre-1962. An upstream dam traps a large proportion of the catchment sediment load, but the upstream retention of flood water has also increased the trapping capacity of the estuary by reducing the freshwater flow. As such, about 22% (33 000 t) more sediment was deposited in the estuary during a 20 year return period flood in May 1996 than would have been deposited prior to dam construction. The sub-tropical Brisbane River estuary has a lower and more variable sediment trapping efficiency than typical temperate northern hemisphere estuaries.

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

    Science.gov (United States)

    Peters, N.E.; Donohue, R.

    2001-01-01

    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 phosphorous (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 1-1 and 0.12 mg 1-1 respectively. The urban drains had higher TP concentrations (volume-weighted mean of 0.21 mg 1-1) than the streams (0.12 mg 1-1), 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 1-1 and 1.5 mg 1-1 respectively) than the streams (0.31 mg 1-1 and 1.2 mg 1-1 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 (<0.01 kg ha-1 year-1 or 32%) to the estuaries. The Avon River nutrient fluxes are much less than other tributaries closer to the estuary. The coastal plain receives significantly higher rainfall (1,200 mm year-1) and has more intense horticulture and animal production than inland areas (<300 mm year-1). Annual rainfall is seasonal, occuring primarily from May through December. The surficial aquifers on the coastal plain generally are sandy with a low nutrient retention capacity, and rapidly transmit soluble and colloidal material in subsurface flow. Ellen Brook, on the coastal plain, drains pastures treated with superphosphate and has the highest FRP (0.51 mg 1-1), TP (0.7 mg 1-1) and TN (2.1 mg 1-1) of any tributary to the estuary. 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. Copyright ?? 2001 John Wiley and Sons, Ltd.

  8. Oil spill response planning on the Columbia river estuary

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2014-11-01

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

  10. Calculation of runoff to an estuary. Ria de Vigo

    OpenAIRE

    Ri?os, Aida F.; Nombela, Miguel Ángel; Pérez, Fiz F.; Rosón, Gabriel; Fraga, Fernando

    1992-01-01

    [EN] Runoff that reaches an estuary was estimated as a function of daily rainfall in the drainage basin when the daily measurements of river flows are not available. This method is applied to the rivers flowing into the Ría de Vigo and compared with the River Deza that reaches the Ría de Arosa where the daily flow and rainfall are known. The optimum value of the retention coefficient (k = 0.75) is calculated. The distribution of flow calculated from the equation obtained and the s...

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

    Science.gov (United States)

    Sanders, Tina; Lassen, Stephan

    2015-04-01

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

  12. Fluxes of nitrogen in Chaliyar River Estuary, India

    Digital Repository Service at National Institute of Oceanography (India)

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

    of nitrate, ammonia and phosphate to sea are 13.7 Mg d-2 , 1.2 Mg d-1 and 0.61 Mg d-1 respectively. Key Words: Tropical Estuary, Nutrient Fluxes, Nitrogen, Seasonal Variation INTRODUCTION The estuarine ecological environments are complex and highly... - August), and during this period, the tidal limit comes down to a distance of 5 Km from the river mouth. The lowest discharges are found to occur during April- May and the tidal incursions of seawater extends up to 2S Km from the river mouth (James...

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

    DEFF Research Database (Denmark)

    Merkel, Flemming Ravn; Johansen, Kasper Lambert

    2011-01-01

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

  14. Microphytobenthos interannual variations in a north-European estuary (Loire estuary, France) detected by visible-infrared multispectral remote sensing

    Science.gov (United States)

    Benyoucef, Ismaïl; Blandin, Elodie; Lerouxel, Astrid; Jesus, Bruno; Rosa, Philippe; Méléder, Vona; Launeau, Patrick; Barillé, Laurent

    2014-01-01

    Estuarine intertidal sediments are colonized by photosynthetic microorganisms grouped under the generic term of microphytobenthos (MPB). These microbial assemblages form transient biofilms at the sediment surface and have important ecosystem functions. MPB biofilms are well known to exhibit high microscale patchiness whereas meso- and macroscale spatio-temporal structures are little known. In this work, satellite remote sensing was used to map MPB assemblages at such scales. MPB interannual distribution was investigated in the poly- and mesohaline domain of the north-European estuary (Loire estuary), using a multispectral SPOT image time series (1991-2009). The Normalized Difference Vegetation Index (NDVI) was calculated from two SPOT channels, XS2 and XS3, (red and near-infrared wavelengths, respectively). MPB biofilms were identified by NDVI values between 0 and 0.3. At the scale of the whole intertidal area, the results showed that MPB biofilms in the Loire estuary exhibited perennial structures in both the polyhaline and mesohaline sectors, occupying nearly 90% of the mudflat surfaces. MPB biofilm density was closely associated with intertidal position, with thicker biofilms developing mostly in the upper and middle shore, and formed kilometric longitudinal structures parallel to the shoreline. Mean NDVI values showed a strong positive correlation with mean seasonal air temperature (? = 0.714, p < 0.05 in the polyhaline domain and ? = 0.810, p < 0.05 in the mesohaline domain), with a strong correlation in the upper intertidal mudflat (between +3 and 4 m isobaths). Negative wind effect was mainly detected in the upper intertidal areas, particularly between the +3 and 4 m isobaths (? = -0.810, p < 0.05 in the polyhaline domain and ? = -0.910 in the mesohaline).

  15. Themes in Southwest Prehistory, edited by George J. Gumerman, 1994

    Directory of Open Access Journals (Sweden)

    Todd W. Bostwick

    1995-11-01

    Full Text Available The 11 chapters by 26 authors in this book result from a School of American Research seminar entitled, "The Organization and Evolution of Prehistoric Southwestern Society, held in September 1989. The goal of the seminar was to have well-known Southwestern scholars consider the entire Southwest as a single but diverse entity, with papers structured according to particular themes, including aggregation, abandonment. warfare, health, and demography.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1979-09-01

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

  17. Evaluation of agricultural extension and delivery services in southwest Nigeria

    OpenAIRE

    Ogunsumi L.O.; Abegunde B.O.

    2011-01-01

    The study on evaluation of agricultural extension and delivery services was carried out in Southwest, Nigeria. The study affirms that participation of people in the achievement of rural development programs in Nigeria, agricultural and non-agricultural, is faced with great challenges. The importance of extension for rural development has been valued quite differently over the course of Nigeria’s rural development efforts. Increasingly, technical change has been recognized as a major pre-requi...

  18. Gerromorpha and Leptopodomorpha (Insecta; Heteroptera) Fauna of Southwest Anatolia

    OpenAIRE

    KIYAK, Suat; SALUR, Ali; CANBULAT, Sava?

    2008-01-01

    This study was based on 1627 specimens belonging to 12 species and 1 subspecies of 8 genera in 7 families of the infraorders Gerromorpha and Leptopodomorpha of the order Heteroptera. The specimens were collected from Southwest Anatolia (provinces Antalya, Burdur, Isparta, Denizli, Ayd?n, and Mu?la) during 2000-2002. Eleven species and 1 subspecies of these are the first records for this area. These species are Mesovelia vittigera (Mesovelidae), Hebrus pusillus (Hebridae), Hydrometra stagnorum...

  19. Echinococcus granulosus Prevalence in Dogs in Southwest Nigeria

    OpenAIRE

    Oyeduntan Adejoju Adediran; Temitope Ubaidat Kolapo; Emmanuel Chibuike Uwalaka

    2014-01-01

    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 ant...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1979-09-01

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

  1. Many southwest hosptials will receive decreased CMS reimbursement

    OpenAIRE

    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 ...

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

    Directory of Open Access Journals (Sweden)

    Angyal, D.

    2013-11-01

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

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

    OpenAIRE

    Angyal, D.; Korsós, Z.

    2013-01-01

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

  4. Factors Associated with Treatment Compliance in Hypertension in Southwest Nigeria

    OpenAIRE

    OSAMOR, PAULINE E.; Owumi, Bernard E.

    2011-01-01

    Hypertension is an important condition among adults, affecting nearly one billion people worldwide. Treatment with appropriate medication is a key factor in the control of hypertension and reduction in associated risk of complications. However, compliance with treatment is often sub-optimal, especially in developing countries. The present study investigated the factors associated with self-reported compliance among hypertensive subjects in a poor urban community in southwest Nigeria. This com...

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

    Directory of Open Access Journals (Sweden)

    Dandara M.M. Bezerra

    2012-09-01

    Full Text Available 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.Este trabalho foi desenvolvido junto a duas comunidades de pescadores artesanais: Barra de Mamanguape e Tramataia, Nordeste do Brasil. O objetivo foi estudar o conhecimento e a percepção dos pescadores artesanais sobre a classificação das marés e dos ventos bem como as técnicas e estratégias de pesca. A metodologia empregada envolveu várias técnicas: entrevistas livres, entrevistas semiestruturadas, turnês guiadas e observação direta. Os resultados obtidos junto aos pescadores mostraram a classificação das marés de acordo com as fases lunares em: 'maré de quebramento', 'maré de lançamento', 'maré morta' e 'maré grande', designadas tecnicamente estas últimas como maré de quadratura e maré de sizígia, respectivamente. O vento é também um fator essencial no sucesso da pescaria, eles o classificam de acordo com a direção: Norte, Sul, Leste, Sudeste, Sudoeste, Nordeste, Noroeste. Os dados obtidos nesta pesquisa mostraram que o conhecimento dos pescadores pode ser útil na elaboração de planos de manejo e nos estudos de conservação para este estuário.

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

    Scientific Electronic Library Online (English)

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

    2012-09-01

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

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

    Science.gov (United States)

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

    2014-11-01

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

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

    Directory of Open Access Journals (Sweden)

    Arefe Emami

    2013-01-01

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

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

    International Nuclear Information System (INIS)

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

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

    Directory of Open Access Journals (Sweden)

    Yen-Chang Chen

    2014-08-01

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

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-06-15

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

  13. Testing a 1-D Analytical Salt Intrusion Model and the Predictive Equation in Malaysian Estuaries

    Science.gov (United States)

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

    2013-04-01

    Little is known about the salt intrusion behaviour in Malaysian estuaries. Study on this topic sometimes requires large amounts of data especially if a 2-D or 3-D numerical models are used for analysis. In poor data environments, 1-D analytical models are more appropriate. For this reason, a fully analytical 1-D salt intrusion model, based on the theory of Savenije in 2005, was tested in three Malaysian estuaries (Bernam, Selangor and Muar) because it is simple and requires minimal data. In order to achieve that, site surveys were conducted in these estuaries during the dry season (June-August) at spring tide by moving boat technique. Data of cross-sections, water levels and salinity were collected, and then analysed with the salt intrusion model. This paper demonstrates a good fit between the simulated and observed salinity distribution for all three estuaries. Additionally, the calibrated Van der Burgh's coefficient K, Dispersion coefficient D0, and salt intrusion length L, for the estuaries also displayed a reasonable correlations with those calculated from the predictive equations. This indicates that not only is the salt intrusion model valid for the case studies in Malaysia but also the predictive model. Furthermore, the results from this study describe the current state of the estuaries with which the Malaysian water authority in Malaysia can make decisions on limiting water abstraction or dredging. Keywords: salt intrusion, Malaysian estuaries, discharge, predictive model, dispersion

  14. Spatial and temporal variation in hexachlorocyclohexane isomers in a temperate estuary.

    Science.gov (United States)

    Padma, Tiruponithura V; Dickhut, Rebecca M

    2002-12-01

    Hexachlorocylcohexanes (HCHs) are pesticides that persist in air and water of the Northern hemisphere. To understand the spatial and temporal variability in HCH levels in estuarine surface waters we measured concentrations of two HCH isomers (alpha-HCH and gamma-HCH) at six sites in the York River estuary at bimonthly intervals for a year. Bacterial abundance and activity were also monitored using acridine orange direct counts and uptake of tritiated substrates, respectively. Alpha-HCH was consistently observed to be significantly higher in marine water compared to river water entering the estuary, suggesting that the Chesapeake Bay or Atlantic Ocean is a larger source of this compound to the York River estuary compared to riverine input. Moreover, following periods of high freshwater flow into the estuary during spring and early summer, both alpha- and gamma-HCH mixing curves indicated an additional source of these pollutants to the estuary such as land-derived runoff or groundwater discharge. In contrast, during low freshwater flow (late summer and fall) the estuary was a sink for HCHs, with y-HCH more rapidly removed from the estuary than alpha-HCH. During the period of low freshwater flow, concentrations of both alpha- and gamma-HCH were negatively correlated with bacterial activity. Bacterial activity as opposed to abundance appears to control HCH degradation in estuarine surface waters. PMID:12523538

  15. Trace metals geochemistry of Bengkulu river and estuary

    Science.gov (United States)

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

    2015-09-01

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

  16. Mathematical simulation of sediment and radionuclide transport in estuaries

    International Nuclear Information System (INIS)

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

  17. An analysis of anomalous southwest United States summer monsoon precipitation

    Science.gov (United States)

    Hall-McKim, Eileen A.

    The North American Monsoon System (NAMS) is an important feature of the atmospheric circulation, and its effects are distinguishable over a large area of the western United States and northwest Mexico. Seasonally warm land surfaces in lowlands and elevated areas, combined with atmospheric moisture supplied by nearby maritime sources, are conducive to monsoon-like systems. The western North American summer precipitation regime plays an important role in the hydrological cycle of the arid southwest U.S. Knowledge of intraseasonal, annual and decadal variations in this system is crucial for forecasting moisture potential availability for management of water resources. This thesis seeks to improve forecasts by evaluating the hypothesis that large-scale variations in atmosphere-ocean-land surface interactions modulate monsoon precipitation in the Southwest. The research examines and quantifies the hypothesized relationships between atmospheric and land-surface processes and anomalous summer rainfall in the Southwest; the primary study area is Arizona and New Mexico. Observed climate data are analyzed to identify variability in precipitation, winds, temperature, humidity, and geopotential height fields of the wettest and driest monsoon seasons of during 1948-2005. Various diagnostic tools have been applied to observed climate data. Preferred modes of atmospheric circulation for anomalous monsoon seasons are identified through the use of climatology, composite and regression analyses of the 57-year data set. Through analysis of monsoon-related climate variables, potential predictors are identified that can be used to develop a model that incorporates such information for monsoon season forecasts, one to three months ahead. Four hypotheses are tested to establish whether relationships exist between antecedent ocean/atmosphere or land surface conditions and monsoon season precipitation. Two hypotheses test the relationship between antecedent sea surface temperatures and antecedent soil moisture conditions and monsoon precipitation. Two other hypotheses test the relationship between early spring ENSO and PDO indices and subsequent monsoon season precipitation. Based on these findings, and the published literature on characteristics of the Southwest summer precipitation regime, a conceptual scheme for a seasonal monsoon forecast has been developed. A discussion follows of implications for southwest monsoon research and prospects for future work.

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

    Directory of Open Access Journals (Sweden)

    Tatsuya Yurimoto

    2014-08-01

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

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

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

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

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

    Digital Repository Service at National Institute of Oceanography (India)

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

    estuary, China. Mar. Chem.93, 21-32. Legend to Figures Figure 1. Sampling locations in the Godavari estuary. Daily time-series sampling was conducted at Yanam, in the middle of the estuary, while monthly sampling was done at all stations. River...-950 Park et al (1969) Potomac (US-Maryland) 646-878 Raymond et al (2000) Changjiang (China- Shanghai/Jiangsu) 168-2264 Gao et al (2008) Changjiang/Yangtze River (China) 700-1950 Chen et al (2008) Pearl River (China-Guangdong) 360-4785 Zhai et al (2005...

  2. Magnetic properties of sediments in cores from the Mandovi estuary, western India: Inferences on provenance and pollution.

    Science.gov (United States)

    Prajith, A; Rao, V Purnachandra; Kessarkar, Pratima M

    2015-10-15

    Magnetic properties of sediments were investigated in 7 gravity cores recovered along a transect of the Mandovi estuary, western India to understand their provenance and pollution. The maximum magnetic susceptibility of sediments was at least 6 times higher in the upper/middle estuary than in lower estuary/bay. The ?fd% and ?ARM/SIRM of sediments indicated coarse, multi-domain and pseudo-single domain magnetic grains, resembling ore material in the upper/middle estuary and coarse stable single domain (SSD) to fine SSD grains in the lower estuary/bay. Mineralogy parameters indicated hematite and goethite-dominated sediments in the upper/middle estuary and magnetite-dominated sediments in the lower estuary/bay. Two sediment types were discernible because of deposition of abundant ore material in the upper/middle estuary and detrital sediment in the lower estuary/bay. The enrichment factor and Index of geo-accumulation of metals indicated significant to strong pollution with respect to Fe and Mn in sediments from the upper/middle estuary. PMID:26210588

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

    Science.gov (United States)

    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-term trends. The SSA is the only analysis, among the four tested, to reach all the criteria and its potential is detailed through examples. We also show how the methods can complement each other. This evaluation contributes to progress in the understanding of sedimentary dynamics in estuaries, but also may be very useful to the time series analysis of other environmental variables.

  4. 2003 Southwest Florida Water Management District (SWFWMD) LiDAR: Marion County

    Data.gov (United States)

    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.

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

    Digital Repository Service at National Institute of Oceanography (India)

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

    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...

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

    Data.gov (United States)

    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...

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

    Digital Repository Service at National Institute of Oceanography (India)

    George, M.D.

    the premonsoon season (February-May). Results of experiments conducted to evaluate the importance of desorption/dissolution revealed that the metal input due to desorption and dissolution of the particulate phase may not be very significant in the estuary...

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

    Data.gov (United States)

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

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

    Digital Repository Service at National Institute of Oceanography (India)

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

    , during the study period. On the other hand, sediment OM in the upper and lower estuaries derived from both autochthonous and allochthonous sources with nearly equal contributions. Although relatively high in situ production was observed in the upper than...

  10. Seasonal variability of physico-chemical characteristics of the Haldia channel of Hooghly estuary, India

    Digital Repository Service at National Institute of Oceanography (India)

    Sadhuram, Y.; Sarma, V.V.; Murty, T.V.R.; Rao, B.P.

    -mail: sadhuram@darya.nio.org Physical and chemical characteristics of the Hooghly estuary during winter (December 1997{ January 1998), summer (May 1998) and post-monsoon (November 1998) seasons have been stud- ied. Salinity varied spatially and temporally...

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

    Digital Repository Service at National Institute of Oceanography (India)

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

    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...

  12. Tidal influence on the diel vertical migration pattern of zooplankton in a tropical monsoonal Estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Vineetha, G.; Jyothibabu, R.; Madhu, N.V.; Kusum, K.K.; Sooria, P.M.; Shivaprasad, A.; Reny, P.D.; Deepak, M.P.

    habitats is often determined by their dominant behavioral patterns: diel vertical migration (DVM) and tidal vertical migration (TVM). The modes of these endogenous rhythms often vary among estuaries based on the river runoff and tidal characteristics...

  13. What’s Upstream? GIS’s critical role in developing nutrient reference conditions for estuaries

    Science.gov (United States)

    Eutrophication due to excess levels of nitrogen and phosphorus can seriously impair ecological function in estuaries. Protective criteria for nutrients are difficult to establish because the source can vary spatially and seasonally, originate either from the watershed or the oce...

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

    Science.gov (United States)

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

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

    Data.gov (United States)

    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...

  16. A Novel Approach for Evaluation of Water Quality Trends in Gulf Coast Estuaries

    Science.gov (United States)

    Water quality data form the backbone of management programs aimed at protecting environmental resources. The increasing availability of long-term monitoring data for estuaries can improve detection of temporal and spatial changes in water quality. However, the relatively simple...

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

    Data.gov (United States)

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

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

    Science.gov (United States)

    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.

  19. Numerical modelling of tidal circulation and studies on salinity distribution in Mandovi and Zuari estuaries

    Digital Repository Service at National Institute of Oceanography (India)

    Manoj, N.T.

    The objectives of the thesis were to determine the characteristics of tidal propagation and salinity distribution in the Mandovi and Zuari estuaries using a hybrid network numerical model. A hybrid network model, consisting of a vertically averaged...

  20. Intra-annual variations of arsenic totals and species in tropical estuary surface sediments

    Digital Repository Service at National Institute of Oceanography (India)

    Chakraborty, P.; Jayachandran, S.; Babu, P.V.R.; Karri, S.; Tyadi, P.; Yao, K.M.; Sharma, B.M.

    Arsenic totals and species were found to vary during a one year period in the surface sediments of Godavari estuary (the third largest river in India). This study suggests that increasing salinity of overlying water column of sediments may alter...

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

    Science.gov (United States)

    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...

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

    Science.gov (United States)

    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...

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

    Science.gov (United States)

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

  4. Biochemical composition and caloric content in the sand whiting Sillago sihama (Forsskal), from Zuari Estuary, Goa

    Digital Repository Service at National Institute of Oceanography (India)

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

    Fish condition as well as the seasonal variation in biochemical composition (moisture content, lipid, protein and carbohydrate) of an economically important fish, Sillago sihama (Forsskal), from Zuari estuary, Goa were monitored over a period...

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

    Digital Repository Service at National Institute of Oceanography (India)

    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...

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

    Science.gov (United States)

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

  7. Distribution of intertidal eelgrass (Zostera marina L.) with bathymetry in three Pacific Northwest estuaries

    Science.gov (United States)

    Distributions of native intertidal eelgrass (Zostera marina L.) and non-vegetated substrates in three coastal estuaries of the Pacific Northwest (PNW) were determined using color infrared (CIR) aerial orthophotography during daylight low tides. Comparison of the digital classif...

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

    Indian Academy of Sciences (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 ?rst 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.

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

    Digital Repository Service at National Institute of Oceanography (India)

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

    in the estuary is protected from contamination and will meet the required quality standards which necessitated the study of tides, current and freshwater flow paths, dispersion potential, flushing time and also the propagation characteristics of the wastewater...

  10. NUTRIENT LIMITATION OF PHYTOPLANKTON GROWTH AND PHYSIOLOGY IN A SUBTROPICAL ESTUARY (PENSACOLA BAY, FL)

    Science.gov (United States)

    Phytoplankton nutrient limitation was studied in a sub-estuary of lower Pensacola Bay using several techniques. Results for phytoplankton were similar. Nutrient-addition bioassays indicated year-round nutrient limitation, in contrast to seasonal patterns often ...

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

    OpenAIRE

    Troost, Karin,

    2009-01-01

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

  12. Application of Biotic Indices in Assessing the Ecological Quality Status of Bahrekan Estuary (Persian Gulf )

    OpenAIRE

    A. Savari; S. M. B. Nabavi; P. Shokat; P. Kochanian

    2010-01-01

    The aim of present study was to examine the macro invertebrates as an assessment tool for characterization of the state of Bahrekan estuary in Persian Gulf, by using different biotic indices. An investigation on benthos was carried out during autumn 2008 to summer 2009 in the Bahrekan estuary (Persian Gulf). In order to identify and assess the benthic community structure, seasonal sampling was done from 21 stations with three replicates using van veen grab (./285 m2). The ecological indices, ...

  13. Use of a Real-Time Remote Monitoring Network (RTRM) to Characterize the Guadalquivir Estuary (Spain)

    OpenAIRE

    Isabel Caballero; Victoria López-Rodas; Javier Ruiz; Laura Prieto; Susana Flecha; Manuel Díez-Minguito; Eduardo Costas; Gabriel Navarro; Isabel Emma Huertas

    2012-01-01

    The temporal variability of hydrological variables in the Guadalquivir estuary was examined during three years through a real-time remote monitoring network (RTRM). The network was developed with the aim of studying the influence of hydrodynamical and hydrological features within the estuary on the functioning of the pelagic ecosystem. Completing this data-gathering network, monthly cruises were performed in order to measure biogeochemical variables that are indicative of the trophic status o...

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

    Science.gov (United States)

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

    1993-01-01

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

  15. Spatial and temporal variability of sediment organic matter recycling in two temperate eutrophicated estuaries

    OpenAIRE

    KHALIL, KARIMA; Raimonet, Melanie; Laverman, Anniet M.; Yan, Chen; Andrieux-loyer, Françoise; Viollier, Eric; Deflandre, Bruno; Ragueneau, Olivier; Rabouille, Christophe

    2013-01-01

    This paper deals with the spatial and seasonal recycling of organic matter in sediments of two temperate small estuaries (Elorn and Aulne, France). The spatio-temporal distribution of oxygen, nutrient and metal concentrations as well as the organic carbon and nitrogen contents in surficial sediments were determined and diffusive oxygen fluxes were calculated. In order to assess the source of organic carbon (OC) in the two estuaries, the isotopic composition of carbon (? 13C) was also measured...

  16. Changes in the diet composition of transitory fishes in coastal systems, estuary and continental shelf

    OpenAIRE

    Paulo T. C. Chaves; Simone C. Umbria

    2003-01-01

    The feeding habits of five species of teleosts in the southern coast of Brazil were analyzed comparatively between estuary and continental shelf. The displacement between the two sites caused expressive qualitative alterations, the proportion of different items varying from 50% in the diet of Micropogonias furnieri to 89% in Isopisthus parvipinnis. In the group of species, 57% of the items were exclusive to one of the environments and, within the three most common items in the estuary - fish,...

  17. Seasonal variation of heavy metals in Mytilus edulis, Fucus vesiculosus and sediment from the Shannon estuary

    OpenAIRE

    Breen, John; O'Leary, Caitriona

    1998-01-01

    Samples of Mytilus edulis, together with samples of sediment and Fucus vesiculosus, were taken monthly from each of five shores on the south coast of the Shannon Estuary from March 1992 to December 1993 inclusive. Samples were digested individually and the levels of iron, zinc, manganese, cobalt, chromium and copper were determined using atomic absorption spectrophotometry. Levels of metals were lower than previously published values from Irish east coast estuaries, including Dublin, except f...

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

    OpenAIRE

    Fidélis, Teresa; Carvalho, Teresa

    2013-01-01

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

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

    DEFF Research Database (Denmark)

    Markager, Stiig; Stedmon, Colin; Søndergaard, Morten

    2011-01-01

    This study presents the results of a year-long study investigating the characteristics of dissolved organic matter (DOM) in the Danish estuary, Horsens Fjord. The estuary is shallow with a mean depth of 2.9 m and receives high loadings of inorganic nutrients from its catchment. The behaviour of different DOM parameters i.e. dissolved organic carbon (DOC), nitrogen (DON), and phosphorous (DOP), light absorption and eight fluorescence components, were analysed relative to conservative mixing. Many...

  20. Numerical modeling of cohesive sediment transport and bed morphology in estuaries

    OpenAIRE

    Leupi, Célestin

    2005-01-01

    Two major lines of investigation have been pursued in this thesis: (1) More efficient, robust and realistic numerical techniques are designed for the simulation of complex turbulent fluid flows; (2) A new algorithm and its analysis is performed in the context of multiphasic fluid flow, for a cohesive fine-grained sediment (fluid mud) transport in estuaries. Estuaries exist between marine and freshwater system where waters of different physical, chemical and biological composition meet, combin...

  1. Cadmium and mercury in Seine Estuary flounders and mussels: the results of two decades of monitoring

    OpenAIRE

    Nakhle, K.; Cossa, Daniel; Claisse, Didier; Beliaeff, Benoit; Simon, S

    2007-01-01

    The flounder (Platichthys flesus) is a flatfish that inhabits marine coastal environments, especially estuaries. It is an alternative quantitative biological indicator to the common marine mussel (Mytilus spp.), which is currently used as a sentinel species to monitor chemical contamination in numerous monitoring programmes. Findings from two decades of monitoring cadmium (Cd) and mercury (Hg) using both sentinel species in the Seine Estuary (France) are reported. For comparison, time-series ...

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

    OpenAIRE

    Geddada Mohan NARASIMHA RAO; Pragada PRAYAGA MURTY

    2010-01-01

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

  3. Influence of benthic macrofauna community shifts on ecosystem functioning in shallow estuaries

    OpenAIRE

    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...

  4. Estuaries as Filters: The Role of Tidal Marshes in Trace Metal Removal

    OpenAIRE

    Teuchies, Johannes; Vandenbruwaene, Wouter; Carpentier, Roos; Bervoets, Lieven; Temmerman, Stijn; Wang, Chen; Maris, Tom; Cox, Tom J. S.; Van Braeckel, Alexander; Meire, Patrick

    2013-01-01

    Flux calculations demonstrate that many estuaries are natural filters for trace metals. Yet, the underlying processes are poorly investigated. In the present study, it was hypothesized that intertidal marshes contribute significantly to the contaminant filter function of estuaries. Trace metal concentrations and sediment characteristics were measured along a transect from the subtidal, over an intertidal flat and marsh to a restored marsh with controlled reduced tide. Metal concentrations in ...

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

    Directory of Open Access Journals (Sweden)

    Kolobov Vladimir Yurievich

    2013-09-01

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

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

    DEFF Research Database (Denmark)

    Lillebo, A. I.; Otero, M.; Coelho, J. P.; Rodrigues, E. T.; Pereira, M. E.; Duarte, A. C.; Pardal, M. A.; Flindt, M. R.

    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 mean concentrations of dissolved inorganic phosphorus (DIP) increased by 50%, due to the increase in winter concentrations, i.e., in periods characterized by lower temperature and lower salinity. Given exi...

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

    OpenAIRE

    Nguyen, A. D.; Savenije, H. H. G.

    2006-01-01

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

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

    Directory of Open Access Journals (Sweden)

    A. D. Nguyen

    2006-04-01

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

  9. Analytical approach for predicting fresh water discharge in an estuary based on tidal water level observations

    OpenAIRE

    Cai, H; Savenije, H. H. G.; Jiang, C

    2014-01-01

    As the tidal wave propagates into an estuary, the tidally averaged water level tends to rise in landward direction due to the density difference between saline and fresh water and the asymmetry of the friction. The effect of friction on the residual slope is even more remarkable when accounting for fresh water discharge. In this study, we investigate the influence of river discharge on tidal wave propagation in the Yangtze estuary with specific attention to ...

  10. Guidelines for determining inputs of inorganic contaminants into estuaries

    International Nuclear Information System (INIS)

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

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

    Directory of Open Access Journals (Sweden)

    Sandra Caeiro

    2003-06-01

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

  12. Geostatistic: a tool for the modeling in estuaries

    International Nuclear Information System (INIS)

    We apply geostatistical methods in the modeling of physical, chemical, and biological variables measured in the Cienaga Grande of Santa Marta estuary, located on the Caribbean coast of Colombia. The information taken in March of 1997 was analyzed in this ecosystem. This data set indicates that the variables introduce strong structures of space dependence and thus the application of Kriging and the subsequent preparation of maps of distribution are recommended in order to give explanation for this type of information. Though the sampling was carried out in the region during the dry season, distribution maps indicate in general that the magnitudes of the variables are more similar to those found traditionally in rainy season, possibly because of consequence of the phenomenon El Nino

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

    Science.gov (United States)

    Jiang, Zhongcheng; Lian, Yanqing; Qin, Xiaoqun

    2014-05-01

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

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

    DEFF Research Database (Denmark)

    Pedersen, Troels MØller; Sand-Jensen, Kaj

    2014-01-01

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

  15. Emissions of biogenic sulfur gases from a danish estuary

    Science.gov (United States)

    Barker Jørgensen, Bo; Okholm-Hansen, Bolette

    The diurnal variations in sulfur emission were studied at seven sites in a Danish estuary, Norsminde Fjord. The sites comprised grass vegetation, intertidal mud flats, accretions of green algae, an exposed shore and a river outlet. Direct measurements of emission rates from soil and water were done by a dynamic flux chamber technique in connection with gas Chromatographie detection and separation of the cryogenically trapped sulfur gases. Sulfur gas concentrations in air and sea water were measured together with emission rates at 0.5-1 h intervals over 25-40 h periods. DMS was the most important sulfur gas released from grass and algae, while mostly H 2S was released from intertidal mud flats. OCS, CH 3SH and CS 2 were released from most sites at lower rates. Emission of DMS followed the daylight variations, often with a delay towards maximum emission rates in the evening. H 2S was mostly emitted at night or in short outbursts during low tides. Total sulfur emission rates were 1-10?mol Sm -2 d -1. Extreme rates of 335?mol DMSm -2 d -1 were measured over decomposing green algae ( Ulva lactuca). H 2S emission fractions were < 10 -6 to 2.10 -4. H 2S was detected, along with DMS, CH 3SH, OCS and CS 2, in the oxic seawater of the estuary at diurnal mean concentrations of 0.1-6.5nmol S/ol -1. This may indicate a more widespread occurrence of H 2S in shallow, near-shore waters at nanomolar levels.

  16. Emissions of biogenic sulfur gases from a Danish estuary

    Energy Technology Data Exchange (ETDEWEB)

    Joergensen, B.B.; Okholm-Hansen, B.

    1985-01-01

    The diurnal variations in sulfur emission were studied at seven sites in a Danish estuary, Norsminde Fjord. The sites comprised grass vegetation, intertidal mud flats, accretions of green algae, an exposed shore and a river outlet. Direct measurements of emission rates from soil and water were done by a dynamic flux chamber technique in connection with gas chromatographic detection and separation of the cryogenically trapped sulfur gases. Sulfur gas concentrations in air and seawater were measured together with emission rates at 0.5-1 h intervals over 25-40 h periods. DMS was the most important sulfur gas released from grass and algae, while mostly H2S was released from intertidal mud flats. OCS, CH3SH and CS2 were released from most sites at lower rates. Emission of DMS followed the daylight variations, often with a delay towards maximum emission rates in the evening. H2S was mostly emitted at night or in short outburst during low tides. Total sulfur emission rates were 1-10 mol S m S d . Extreme rates of 335 mol DMS m S d were measured over decomposing green algae (Ulva lactuca). H2S emission fractions were < 10 W to 2 x 10 U. H2S was detected, along with DMS, CH3SH, OCS and CS2, in the oxic seawater of the estuary at diurnal mean concentrations of 0.1-6.5 nmol Sl . This may indicate a more widespread occurrence of H2S in shallow, near-shore waters at nanomolar levels.

  17. Numerical simulation of water quality in Yangtze Estuary

    Directory of Open Access Journals (Sweden)

    Xi LI

    2009-12-01

    Full Text Available In order to monitor water quality in the Yangtze Estuary, water samples were collected and field observation of current and velocity stratification was carried out using a shipboard acoustic Doppler current profiler (ADCP. Results of two representative variables, the temporal and spatial variation of new point source sewage discharge as manifested by chemical oxygen demand (COD and the initial water quality distribution as manifested by dissolved oxygen (DO, were obtained by application of the Environmental Fluid Dynamics Code (EFDC with solutions for hydrodynamics during tides. The numerical results were compared with field data, and the field data provided verification of numerical application: this numerical model is an effective tool for water quality simulation. For point source discharge, COD concentration was simulated with an initial value in the river of zero. The simulated increments and distribution of COD in the water show acceptable agreement with field data. The concentration of DO is much higher in the North Branch than in the South Branch due to consumption of oxygen in the South Branch resulting from discharge of sewage from Shanghai. The DO concentration is greater in the surface layer than in the bottom layer. The DO concentration is low in areas with a depth of less than 20 m, and high in areas between the 20-m and 30-m isobaths. It is concluded that the numerical model is valuable in simulation of water quality in the case of specific point source pollutant discharge. The EFDC model is also of satisfactory accuracy in water quality simulation of the Yangtze Estuary.

  18. Modeling study of flocculation effects on sediment transport in estuaries

    Science.gov (United States)

    Xu, Fanghua

    Our current understanding of sediment transport in rivers and estuaries is insufficient to permit quantitative predictions of the fate of fine-grained sediment particles. In order to improve our ability to model sediment transport and depositional patterns, flow models need to be coupled with models that allow for the creation and destruction of flocs and subsequent changes in their settling velocity. A size-resolved flocculation model has been developed and tested to fulfill this goal. The flocculation model can predict the temporal evolution of the floc size distribution undergoing aggregation and breakup. In addition to flocculation, a one-dimensional (1-D) model has been developed where we consider particle settling, deposition and erosion and calculate the floc size distribution depending on friction velocity. The 1-D simulation is verified by comparing with observed size distributions over tidal cycles by Bale et al. [2002]. The flocculation scheme has been successfully incorporated with the sediment transport component in a 3-D hydrodynamic circulation model (Princeton Ocean Modeling (POM)). An idealized study to simulation of ETM variations over tidal cycles has been carried out. The continuous variations in floc size and settling velocity from the model study indicate that a fixed settling velocity does not well represent particle settling. The combination of gravitational circulation convergence and tidal asymmetry associated with settling flocs are primarily responsible for an ETM formation. Lateral circulation in estuaries which results in cross-channel transport of water mass and suspended sediments is important for lateral trapping of particles and formation of axial asymmetrical channel profile. An idealized three-dimensional simulation is done to investigate the effects of lateral circulation on lateral trapping of sediments associated with flocculation processes.

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

    Science.gov (United States)

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

    2015-03-01

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

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

    Directory of Open Access Journals (Sweden)

    Regla Duthit Somoza

    2011-04-01

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

  1. A classification of U.S. estuaries based on physical and hydrologic attributes

    Science.gov (United States)

    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.

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

    Science.gov (United States)

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

    2012-01-24

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

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

    DEFF Research Database (Denmark)

    Guelinckx, J.; Maes, J.

    2006-01-01

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

  4. Facilitation of the Estuary/Ocean Subgroup for Research, Monitoring, and Evaluation, FY06 Annual Report

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Gary E.

    2006-10-03

    This annual report is a deliverable for fiscal year 2006 (FY06) 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 the 2000 and 2004 Biological Opinions on operation of the Federal Columbia River Power System. The goal of the EOS project is to facilitate activities of the estuary/ocean RME subgroup as it coordinates implementation of the Estuary RME Plan. In FY06, 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 May 2006) based on comments by EOS members, the Independent Scientific Review Panel, and other reviewers. In the context of uncertainty about the direction of the federal RME due to litigation on the FCRPS Biological Opinion, FY06 activities for the EOS project resulted in expanded substantive coordination with other regional RME forums, project tracking infrastructure, and a new version of the Estuary RME Plan.

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

    Science.gov (United States)

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

    2015-01-01

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

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

    DEFF Research Database (Denmark)

    Merkel, Flemming Ravn; Johansen, Kasper Lambert

    2011-01-01

    Light-induced bird strikes are known to occur when vessels navigate during darkness in icy waters using powerful searchlight. In Southwest Greenland, which is important internationally for wintering seabirds, we collected reports of incidents of bird strikes over 2–3 winters (2006–2009) from navy vessels, cargo vessels and trawlers (total n = 19). Forty-one incidents were reported: mainly close to land (<4 km, 78%), but one as far offshore as 205 km. Up to 88 birds were reported killed in a sing...

  7. Speciation of metals and their distribution in tropical estuarine mudflat sediments, southwest coast of India.

    Science.gov (United States)

    Fernandes, Maria C; Nayak, G N

    2015-12-01

    Two sediment cores collected from a mudflat sedimentary environment of Swarna estuary (S3) and Gurpur estuary (MF6), representing the middle estuarine region, Karnataka, India, were investigated to understand bioavailability of metals and their toxicity. The subsamples were analyzed for sand, silt, clay, organic carbon and total metal concentration of Aluminum (Al), Iron (Fe), Manganese (Mn), Nickel (Ni), Zinc (Zn), Copper (Cu), Cobalt (Co) and Chromium (Cr) at 2cm intervals. Sediments (average) are relatively coarser in Gurpur estuary whereas silt, clay, organic carbon along with the studied metals (except Mn and Cu) is noted to be higher in the Swarna estuary. Significant correlations were observed of Al, Fe with finer sediments and most of the trace metals in both the cores indicating a mainly lithogenic source. Further, metal speciation analysis carried out for Fe, Mn, Ni, Zn, Cu, Co and Cr on selected samples of both the cores indicated that Fe was largely associated with the residual fraction with 93±0.5% in Gurpur and 84±6% in Swarna estuary. The concentration of studied metals in the residual fraction in the sediments of Gurpur estuary was in the order Mn(90±5%)>Cr(85±1%)>Ni(72±5%)>Zn(69±3%)>Cu(57±5%)>Co(55±2%) and; Cr(80±7%)>Mn(77±10%)>Ni(76±7%)>Zn(67±10%)>Cu(67±10%)>Co(50±7%) in Swarna estuary. When the total (bulk) metals were compared with the Sediment Quality Values (SQV) following Screening Quick Reference Table (SQUIRT), Co values of both the cores fell above Apparent Effect Threshold (AET) values. When the sum of the average bioavailable fractions in sediments was considered, Co values exceeded the AET in core S3 (Swarna estuary). When the variations are viewed with depth, bioavailability of Mn, Ni, Cu and Co in Gurpur estuary indicated anthropogenic addition in recent years whereas in Swarna estuary most of the studied metals showed diagenetic remobilization and diffusion to the water column from surface sediments. Metal speciation study indicated no harm to the aquatic life, except of Co, in Swarna estuary wherein it posed a high risk of toxicity to organisms associated with the sediments. PMID:26210609

  8. Long term variation of an amphipod species’ population secondary production as indicator of incomplete resilience in a temperate estuary

    OpenAIRE

    Leite, Nuno; Guerra, Alexandra; Almeida, Alda; Marques, João Carlos; Martins, Irene

    2014-01-01

    During the last decades many estuaries underwent ranges of environmental pressure due to increasing anthropogenic pressures and the undertaken of mitigation measures to prevent the impoverishment of these areas. The Mondego estuary (NW Atlantic coast of Portugal), a mesotidal shallow estuary, is one typical case of this. In the 1980s, the system was characterized by rich and stable animal and vegetal communities, with no eutrophication symptoms (pre-eutrophication period), whereas...

  9. Haemocytic leukemia in Prince Edward Island (PEI) soft shell clam (Mya arenaria): Spatial distribution in agriculturally impacted estuaries

    International Nuclear Information System (INIS)

    Intensive farming of potatoes in Prince Edward Island (PEI) relies on the repeated and widespread application of fertilizers and pesticides. In PEI the main potato farming areas are in close proximity and drain directly to estuaries. Runoff from high agricultural activity watersheds could impact benthic organism health in the depositional zone of downstream estuaries. The estuarine filter feeder Mya arenaria (soft-shell clam) could be particularly vulnerable to both particle-adsorbed and water soluble contaminants. M. arenaria is susceptible to haemocytic leukemia. In May 2009, we established that heavily proliferated leukemia (HPL) prevalence was generally higher in PEI estuaries located downstream of high intensity potato farming (Dunk and Wilmot estuaries) watersheds than in estuaries downstream of lower intensity areas. Using Mab-1E10 based immunocytochemistry we observed that leukemic haemocytes from the Dunk and Wilmot estuaries were 1E10 negative whereas those from the Ox/Sheep estuary (low potato farming intensity) were 1E10 positive. The expression of genes in the p53 tumour suppressor pathway enabled us to differentiate groups of leukemic and normal M. arenaria, validating our diagnoses. In October 2009, we confirmed that HPL prevalence was elevated in the Dunk and Wilmot estuaries compared to reference (Souris River). Moreover, leukemia prevalence declined with distance from the river mouths along transects through the Dunk and Wilmot estuaries. The pesticides ß-endosulfan and ?-endosulfan were detected in surface sediments from the Dunk and Wilmot estuaries, but not in sediments from either the Souris River or several other lower intensity potato farming watersheds. Our study provides evidence of an association between intensity of potato farming and prevalence of clam leukemia at downstream estuaries in PEI. - Highlights: ? We examined leukemia prevalence in PEI clams Mya arenaria. ? Prevalence was generally higher downstream of high intensity potato farming. ? Leukemia prevalence declined with distance from source in two impacted estuaries. ? Proteins, gene expression and immunology confirm diagnosis of disease. ? Intensive potato farming may contribute to prevalence of clam leukemia in PEI.

  10. 33 CFR 207.200 - Mississippi River below mouth of Ohio River, including South and Southwest Passes; use...

    Science.gov (United States)

    2010-07-01

    ...2010-07-01 2010-07-01 false Mississippi River below mouth of Ohio River, including South and Southwest Passes; use...NAVIGATION REGULATIONS § 207.200 Mississippi River below mouth of Ohio River, including South and Southwest Passes;...

  11. 33 CFR 162.80 - Mississippi River below mouth of Ohio River, including South and Southwest passes.

    Science.gov (United States)

    2010-07-01

    ...2010-07-01 2010-07-01 false Mississippi River below mouth of Ohio River, including South and Southwest passes. 162...NAVIGATION REGULATIONS § 162.80 Mississippi River below mouth of Ohio River, including South and Southwest passes....

  12. Relationships among the monsoon-like southwest Australian circulation, the Southern Annular Mode, and winter rainfall over southwest Western Australia

    Science.gov (United States)

    Feng, Juan; Li, Jianping; Li, Yun; Zhu, Jianlei; Xie, Fei

    2015-08-01

    This study examines the relationships among the monsoon-like southwest Australian circulation (SWAC), the Southern Annular Mode (SAM), and southwest Western Australia winter rainfall (SWR), based on observed rainfall, reanalysis datasets, and the results of numerical modeling. By decomposing the SWAC into two components using a linear model, i.e. the component related to SAM (RSAM) and the component unrelated to SAM (SWACI*), we find it is the SWACI* that shows a significant influence on SWR. Similarly, it is the component of SAM associated with SWAC that exhibits an impact on SWR, whereas the component unrelated to SAM. A similar result is obtained in terms of the circulation associated with SWAC and the SAM. These facts suggest the SAM plays an indirect role in influencing SWR, and raise the possibility that SWAC acts as a bridge between the SAM and SWR, by which the SAM passes its influences onto SWR. This is due to the fact that the variations of SWAC are closely linked to the thermal contrast between land and sea across the southern Indian Ocean and southwest Australia. By contrast, the SAM does not significantly relate to this thermal structure, particularly for the component unrelated to SWAC. The variations of surface sea temperature over the southern Indian Ocean contribute to the favored rainfall circulation patterns. This finding is supported by the numerical modeling results. The strong coupling between SWAC and SWR may be instrumental for understanding the interactions between SWR and the southern Indian Ocean, and provides another perspective in examining the variations in SWR.

  13. Granitoids of South Korea and Southwest Japan. Trace element evidence regarding their differentiation

    Energy Technology Data Exchange (ETDEWEB)

    Tsusue, Akio; Mizuta, Toshio [Kumamoto Univ. (Japan). Faculty of Science; Tamai, Tadaharu

    1994-07-01

    Although we have already published our trace element data for granitoids of South Korea and Southwest Japan, and we have interpreted REE patterns and Ba, Rb and Sr relationships of the granitoids (Tsusue et al., 1986, 1987a, 1987b, 1988), we intend to review briefly the trace element data of South Korea and Southwest Japan in this report. (J.P.N.).

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

    OpenAIRE

    Steven M. Wu

    2012-01-01

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

  15. Intense Southwest Florida hurricane landfalls over the past 1000 years

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    C. Volta

    2015-07-01

    Full Text Available 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 end-member systems covering the main features of tidal alluvial estuaries. 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 end-member 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. This translates into a first-order, global CO2 outgassing flux for tidal estuaries between 0.04 and 0.07 Pg C yr?1. N filtering capacities, calculated in similar fashion, range from 22% for the marine estuary to 18 and 15% for the mixed and the riverine estuary, respectively. 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 indicate that all end-member estuaries will remain net heterotrophic and while the riverine and mixed systems will only marginally be affected by river load changes and increase in atmospheric pCO2, the marine estuary is likely to become a significant CO2 sink in its downstream section. In the decades to come, such change of behavior might strengthen the overall CO2 sink of the estuary-coastal ocean continuum.

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

    Science.gov (United States)

    Volta, C.; Laruelle, G. G.; Arndt, S.; Regnier, P.

    2015-07-01

    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 end-member systems covering the main features of tidal alluvial estuaries. 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 end-member 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. This translates into a first-order, global CO2 outgassing flux for tidal estuaries between 0.04 and 0.07 Pg C yr-1. N filtering capacities, calculated in similar fashion, range from 22% for the marine estuary to 18 and 15% for the mixed and the riverine estuary, respectively. 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 indicate that all end-member estuaries will remain net heterotrophic and while the riverine and mixed systems will only marginally be affected by river load changes and increase in atmospheric pCO2, the marine estuary is likely to become a significant CO2 sink in its downstream section. In the decades to come, such change of behavior might strengthen the overall CO2 sink of the estuary-coastal ocean continuum.

  18. Sequence stratigraphic and sedimentologic significance of biogenic structures from a late Paleozoic marginal- to open-marine reservoir, Morrow Sandstone, subsurface of southwest Kansas, USA

    Science.gov (United States)

    Buatois, Luis A.; Mángano, M. Gabriela; Alissa, Abdulrahman; Carr, Timothy R.

    2002-09-01

    Integrated ichnologic, sedimentologic, and stratigraphic studies of cores and well logs from Lower Pennsylvanian oil and gas reservoirs (lower Morrow Sandstone, southwest Kansas) allow distinction between fluvio-estuarine and open marine deposits in the Gentzler and Arroyo fields. The fluvio-estuarine facies assemblage is composed of both interfluve and valley-fill deposits, encompassing a variety of depositional environments such as fluvial channel, interfluve paleosol, bay head delta, estuary bay, restricted tidal flat, intertidal channel, and estuary mouth. Deposition in a brackish-water estuarine valley is supported by the presence of a low diversity, opportunistic, impoverished marine ichnofaunal assemblage dominated by infaunal structures, representing an example of a mixed, depauperate Cruziana and Skolithos ichnofacies. Overall distribution of ichnofossils along the estuarine valley was mainly controlled by the salinity gradient, with other parameters, such as oxygenation, substrate and energy, acting at a more local scale. The lower Morrow estuarine system displays the classical tripartite division of wave-dominated estuaries (i.e. seaward-marine sand plug, fine-grained central bay, and sandy landward zone), but tidal action is also recorded. The estuarine valley displays a northwest-southeast trend, draining to the open sea in the southeast. Recognition of valley-fill sandstones in the lower Morrow has implications for reservoir characterization. While the open marine model predicts a "layer-cake" style of facies distribution as a consequence of strandline shoreline progradation, identification of valley-fill sequences points to more compartmentalized reservoirs, due to the heterogeneity created by valley incision and subsequent infill. The open-marine facies assemblage comprises upper, middle, and lower shoreface; offshore transition; offshore; and shelf deposits. In contrast to the estuarine assemblage, open marine ichnofaunas are characterized by a high diversity of biogenic structures representing the activity of a benthic fauna developed under normal salinity conditions. Trace fossil and facies analyses allow environmental subdivision of the shoreface-offshore successions and suggest deposition in a weakly storm-affected nearshore area. An onshore-offshore replacement of the Skolithos ichnofacies by the Cruziana ichnofacies is clearly displayed. The lower Morrow fluvio-estuarine valley was incised during a drop of sea level coincident with the Mississippian-Pennsylvanian transition, but was mostly filled during a subsequent transgression. The transgressive nature of the estuarine infill is further indicated by the upward replacement of depauperate brackish-water trace fossil assemblages by the open-marine Cruziana ichnofacies. Additional stratal surfaces of allostratigraphic significance identified within the estuary include the bayline surface, the tidal ravinement surface, the wave ravinement surface, and a basinwide flooding surface recording inundation of the valley interfluves. A younger sequence boundary within the lower Morrow is also recorded in the Gentzler field at the base of a forced regression shoreface, demarcated by the firmground Glossifungites ichnofacies, indicating a rapid basinward facies migration during a sea-level drop. Trace fossil models derived from the analysis of Mesozoic and Cenozoic reservoirs are generally applicable to the study of these late Paleozoic reservoirs. Pennsylvanian brackish-water facies differ ichnologically from their post-Paleozoic counterparts, however, in that they have: (1) lower trace fossil diversity, (2) lower degree of bioturbation, (3) scarcity of crustacean burrows, (4) absence of firmground suites, and (5) absence of ichnotaxa displaying specific architectures designed to protect the tracemaker from salinity fluctuations. Morrow open-marine ichnofaunas closely resemble their post-Paleozoic equivalents.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-05-15

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

  20. 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

    Data.gov (United States)

    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...

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

    Scientific Electronic Library Online (English)

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

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

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

    DEFF Research Database (Denmark)

    Markager, Stiig; Stedmon, Colin

    2011-01-01

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

  3. Seasonal distribution and interactions between plankton and microplastics in a tropical estuary

    Science.gov (United States)

    Lima, A. R. A.; Barletta, M.; Costa, M. F.

    2015-11-01

    The seasonal migration of a salt wedge and rainfall were the major factors influencing the spatiotemporal distribution of ichthyoplankton and microplastics along the main channel of the Goiana Estuary, NE Brazil. The most abundant taxa were the clupeids Rhinosardinia bahiensis and Harengula clupeola, followed by the achirid Trinectes maculatus (78.7% of the catch). Estuarine and mangrove larvae (e.g. Anchovia clupeoides, Gobionellus oceanicus), as well as microplastics were ubiquitous. During drier months, the salt wedge reaches the upper estuary and marine larvae (e.g. Cynoscion acoupa) migrated upstream until the zones of coastal waters influence. However, the meeting of waterfronts in the middle estuary forms a barrier that retains the microplastics in the upper and lower estuary most part of the year. During the late dry season, a bloom of zooplankton was followed by a bloom of fish larvae (12.74 ind. 100 m-3) and fish eggs (14.65 ind. 100 m-3) at the lower estuary. During the late rainy season, the high freshwater inflow flushed microplastics, together with the biota, seaward. During this season, a microplastic maximum (14 items 100 m-3) was observed, followed by fish larvae maximum (14.23 ind. 100 m-3) in the lower estuary. In contrast to fish larvae, microplastics presented positive correlation with high rainfall rates, being more strictly associated to flushing out/into the estuary than to seasonal variation in environmental variables. Microplastics represented half of fish larvae density. Comparable densities in the water column increase the chances of interaction between microplastics and fish larvae, including the ingestion of smaller fragments, whose shape and colour are similar to zooplankton prey.

  4. The effects of hydrological dynamics on benthic diatom community structure in a highly stratified estuary: The case of the Ebro Estuary (Catalonia, Spain)

    Science.gov (United States)

    Rovira, L.; Trobajo, R.; Leira, M.; Ibáñez, C.

    2012-04-01

    This study of the distribution of benthic diatom assemblages and their relationship with environmental factors in a highly stratified Mediterranean estuary, i.e. the Ebro Estuary, shows the importance of hydrological dynamics to explain the features of the diatom community in such an estuary, where river flow magnitude and fluctuations imply strong physicochemical variability especially in sites close to the sea. Eight sites along the estuary were sampled during 2007-2008 both at superficial and deep water layers, in order to gather both horizontal and vertical estuarine physicochemical and hydrological gradients. Canonical Variates Analysis and Hierarchical Cluster Analysis segregated diatom community in two assemblages depending on the dynamics of the salt-wedge. The diatom assemblages of riverine conditions (i.e. without salt-wedge influence) where characterised by high abundances of Cocconeis placentula var. euglypta and Amphora pediculus, meanwhile high abundances of Nizschia frustulum and Nitzschia inconspicua were characteristic of estuarine conditions (i.e. under salt-wedge influence). Redundancy Analysis showed that both diatom assemblages responded seasonally to Ebro River flows, especially in estuarine conditions, where fluctuating conditions affected diatom assemblages both at spatial and temporal scale.

  5. Haemocytic leukemia in Prince Edward Island (PEI) soft shell clam (Mya arenaria): spatial distribution in agriculturally impacted estuaries.

    Science.gov (United States)

    Muttray, Annette; Reinisch, Carol; Miller, Jason; Ernst, William; Gillis, Patricia; Losier, Melanie; Sherry, James

    2012-05-01

    Intensive farming of potatoes in Prince Edward Island (PEI) relies on the repeated and widespread application of fertilizers and pesticides. In PEI the main potato farming areas are in close proximity and drain directly to estuaries. Runoff from high agricultural activity watersheds could impact benthic organism health in the depositional zone of downstream estuaries. The estuarine filter feeder Mya arenaria (soft-shell clam) could be particularly vulnerable to both particle-adsorbed and water soluble contaminants. M. arenaria is susceptible to haemocytic leukemia. In May 2009, we established that heavily proliferated leukemia (HPL) prevalence was generally higher in PEI estuaries located downstream of high intensity potato farming (Dunk and Wilmot estuaries) watersheds than in estuaries downstream of lower intensity areas. Using Mab-1E10 based immunocytochemistry we observed that leukemic haemocytes from the Dunk and Wilmot estuaries were 1E10 negative whereas those from the Ox/Sheep estuary (low potato farming intensity) were 1E10 positive. The expression of genes in the p53 tumour suppressor pathway enabled us to differentiate groups of leukemic and normal M. arenaria, validating our diagnoses. In October 2009, we confirmed that HPL prevalence was elevated in the Dunk and Wilmot estuaries compared to reference (Souris River). Moreover, leukemia prevalence declined with distance from the river mouths along transects through the Dunk and Wilmot estuaries. The pesticides ß-endosulfan and ?-endosulfan were detected in surface sediments from the Dunk and Wilmot estuaries, but not in sediments from either the Souris River or several other lower intensity potato farming watersheds. Our study provides evidence of an association between intensity of potato farming and prevalence of clam leukemia at downstream estuaries in PEI. PMID:22425172

  6. Sticky stuff! Seasonal flocculation in a hypertidal estuary

    Science.gov (United States)

    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 significant resistance to breakup. These changes significantly altered the Ws of SPM within the estuary, which would affect particle flux as Ws for similar density particles in summer may be in excess of nine times greater during summer than in winter. Models with a constant settling velocity may therefore be inaccurate.

  7. Fishes and fisheries in tropical estuaries: The last 10 years

    Science.gov (United States)

    Blaber, S. J. M.

    2013-12-01

    Since 2002 there has been an increase in knowledge of many aspects of the biology and ecology of tropical estuarine fishes, as well as significant changes to many estuarine fisheries. Analyses of literature databases (2002-2012) show that: of the c. 600 relevant papers, 52% are primarily related to ecology, 11% to conservation, 11% to anthropogenic and pollution effects on fishes, 9% to fisheries, 7% to aquaculture, 4% to study techniques, and 1% each to fish larvae, effects of fishing, taxonomy, climate change, evolution and genetics. In terms of geographic spread 17% are from North America, 15% from south Asia, 14% from the Caribbean, 13% from Australasia, 12% from Africa and 9% each from South America and SE Asia. Research papers came from 50 countries of which the dominant were USA (15%), India (12%), Australia (11%) and Brazil (7%). Increasing numbers of studies in West Africa, SE and South Asia and South America have increased basic knowledge of the ecology of estuarine fish faunas. Increases in understanding relate to: roles of salinity, turbidity and habitat diversity; connectivity between habitats; water flow; ecological drivers of spatial variability; scale dependent variation; thermal tolerances; movement patterns; food webs; larval adaptations; and the viability of areas heavily impacted by human activities. New reviews both challenge and support different aspects of the estuarine dependence paradigm - still perhaps one of the main research issues - and the protective function of estuaries and mangroves for juvenile fishes has received attention in relation to e.g. predation risks and fisheries. There have also been significant advances in the use of guilds and biodiversity models. Fishing pressures have continued unabated in most tropical estuaries and are summarised and management issues discussed. Understanding of the relationships between fisheries production and mangroves has advanced and significant differences have emerged between Indo-West Pacific and Atlantic systems. The effects of fishing itself have also received attention and research is often related to conservation studies. The effects of anthropogenic activities are reviewed and important advances in mitigation are discussed. Restoration of estuarine habitats, such as mangroves, previously taking place mainly in countries such as Australia and USA, is now occurring in more countries. The design of reserves and the use of protected areas as management tools are gaining credence. Finally, the evidence for actual and potential effects of climate change is discussed.

  8. Remote Sensing Technologies for Estuary Research and Management (Invited)

    Science.gov (United States)

    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 processes and forecast responses to change. We demonstrate that innovative remote sensing technologies, coupled with long term datasets from satellite earth observing missions and in situ sensor networks provide the spatially contiguous measurements needed to make 'supra-regional' (e.g. river to coast) assessments of ecological communities, habitat distribution, ecosystem function, sediment, nutrient and carbon source and transport. We show that this information can be used to improve environmental modeling with increased confidence and support informed environmental management.

  9. Distribution of Epiphytic Diatoms in a Sub-Tropical Estuary

    Science.gov (United States)

    Frankovich, T. A.; Gaiser, E. E.; Wachnicka, A.; Zieman, J. C.

    2005-05-01

    Within estuaries, seagrasses may represent an order of magnitude greater surface area relative to sediments for the colonization and growth of diatoms. Fossil diatom distributions have proven useful in inferring paleoenvironmental conditions. The strength of these inferences is dependent upon defining the environmental relationships of contempory diatom compositions. The present investigation characterized the modern epiphytic diatom flora on the seagrass Thalassia testudinum at seven sites in the sub-tropical Florida Bay estuary and at one Atlantic Ocean site east of the upper Florida Keys. These sites were sampled six times between March 2000 and April 2001. Diatom species composition was related to water quality parameters using multivariate statistics. 338 diatom species were identified. The seven most abundant species from pooled samples were Cocconeis placentula, Brachysira aponina, Nitzschia liebetruthii, Hyalosynedra laevigata, Amphora cf. tenerrima, Mastogloia crucicula, and M. pusilla. These seven species collectively accounted for 51.7 percent of all valves counted and occurred in at least 85 percent of all samples. Analysis of similiarity and NMDS ordination of species relative abundances revealed four distinct diatom communities across the study region. The spatial variability of these communities was correlated with salinity and water-column nutrient availability. Summertime communities were significantly different from winter-spring communities, but these communities showed a gradual temporal progression with much overlap. The temporal variability was correlated with temperature. Indicator species analysis identified many species significantly influencing the four spatial groups. The Atlantic marine site was characterized by many different Mastogloia species and some epipsammic (sand-grain associated) diatoms (i.e., Cymatosira lorenziana, Dimerogramma dubium, and Neofragilaria nicobarica). Mastogloia pusilla, Rhopalodia pacifica, and Cocconeis woodii were strong indicators of the Gulf of Mexico marine site. Reimerothrix floridensis was particularly abundant in the western interior of Florida Bay (i.e., sites 2, 3, and 4) during summer months. The eastern interior of Florida Bay was characterized by high relative abundances of Brachysira aponina and Nitzschia liebetruthii. The optima and tolerance of these indicator species relative to individual water quality parameters were also determined.

  10. Understanding the Influence of Retention Basin on Tidal Dynamics in Tidal Estuaries

    Science.gov (United States)

    Kumar, Mohit; Schuttelaars, Henk; Roos, Pieter

    2014-05-01

    Both the tidal motion and suspended sediment concentration (SSC) in tidal embayments and estuaries are influenced by anthropogenic (e.g. deepening ) and natural changes. An example of such an estuary is the Ems estuary, situated on the border of the Netherlands and Germany. The mean tidal range towards the end of the Ems estuary has increased from 1.5m in the 1950s to more than 3m in the 1990s while the suspended concentration has increased by a factor 10. To possibly reduce these negative effects, the construction of retention basin(s) (RB) is considered. In this contribution, the influence of location and geometry of RBs on tidal dynamics and SSC is investigated. For this purpose, a three-dimensional semi-analytic idealized model is developed. This model is an extension of the model proposed by Winant (2007) to arbitrary domain and realistic bathymetry with partial slip boundary condition at the bottom. The sea surface elevation (SSE) is calculated numerically using a finite element method. Next, the three-dimensional velocities are calculated by combining the analytically calculated vertical profiles and the gradients of the SSE which are obtained numerically. Firstly, the influence of a RB on the tidal dynamics in an infinitely long, rectangular, frictionless estuary is considered. The SSE decreases when the RB is located between a node and a landward antinode, consistent with the work of Alebregtse et al. (2013). Secondly, an estuary of finite length is connected to a sea. By varying the width of the sea, not only the effect of the distance of the RB to the landward end plays a role, but also the distance to the open sea becomes important. Finally, we discuss the influence of a RB on the tidal motion and initial sediment transport, considering the Ems estuary with realistic bathymetry. Results show that the SSE at the landward end of the Ems estuary decreases for all locations of the RBs. This decrease is most pronounced for the RB which is closest to the end of the Ems estuary. Concerning the initial sediment transport, introduction of a RB creates a convergence zone at the location of RB with enhanced along-channel transport seaward and reduced along-channel transport landward of the location of the RB. The intensity of the change in the along-channel transport decreases as the RB is located closer to the landward end. A Similar trend is obtained for cross-channel transport, meaning that the RB will fill more slowly when located closer to the end. The mechanisms resulting in these observed changes, and their sensitivity to the parameters (such as friction, geometry of RBs ,etc) will be discussed in detail.

  11. A theoretical framework for analyzing the effect of external change on tidal dynamics in estuaries

    Science.gov (United States)

    CAI, H.; Savenije, H.; Toffolon, M.

    2013-12-01

    The most densely populated areas of the world are usually located in coastal areas near estuaries. As a result, estuaries are often subject to intense human interventions, such as dredging for navigation, dam construction and fresh water withdrawal etc., which in some areas has led to serious deterioration of invaluable ecosystems. Hence it is important to understand the influence of such interventions on tidal dynamics in these areas. In this study, we present one consistent theoretical framework for tidal hydrodynamics, which can be used as a rapid assessment technique that assist policy maker and managers to make considered decisions for the protection and management of estuarine environment when assessing the effect of human interventions in estuaries. Analytical solutions to the one-dimensional St. Venant equations for the tidal hydrodynamics in convergent unbounded estuaries with negligible river discharge can be cast in the form of a set of four implicit dimensionless equations for phase lag, velocity amplitude, damping, and wave celerity, as a function of two localized parameters describing friction and convergence. This method allows for the comparison of the different analytical approaches by rewriting the different solutions in the same format. In this study, classical and more recent formulations are compared, showing the differences and similarities associated to their specific simplifications. The envelope method, which is based on the consideration of the dynamics at high water and low water, can be used to derive damping equations that use different friction approximations. This results in as many analytical solutions, and thereby allows one to build a consistent theoretical framework. Analysis of the asymptotic behaviour of the equations shows that an equilibrium tidal amplitude exits reflecting the balance between friction and channel convergence. The framework is subsequently extended to take into account the effect of river discharge. Hence, the analytical solutions are applicable even in the upstream part of an estuary, where the influence of river discharge is remarkable. The proposed analytical solutions are transparent and practical, allowing a quantitative and qualitative assessment of human interventions (e.g., dredging, flow reduction) on tidal dynamics. Moreover, they are rapid assessment techniques that enable the users to set up a simple model and to understand the functioning of the system with a minimum of information required. The analytical model is illustrated in three large-scale estuaries with significant influence by human activities, i.e., the Scheldt estuary in the Netherlands, the Modaomen and the Yangtze estuaries in China. In these estuaries, the correspondence with observations is good, which suggests that the proposed model is a useful, yet realistic and reliable instrument for quick detection of the effect of human interventions on tidal dynamics and subsequent environmental issues, such as salt intrusion.

  12. Freshwater scarcity effects on the aquatic macrofauna of a European Mediterranean-climate estuary.

    Science.gov (United States)

    González-Ortegón, Enrique; Baldó, Francisco; Arias, Alberto; Cuesta, Jose A; Fernández-Delgado, Carlos; Vilas, César; Drake, Pilar

    2015-01-15

    In the Mediterranean-climate zone, recurrent drought events and increasing water demand generally lead to a decrease in freshwater input to estuaries. This water scarcity may alter the proper function of estuaries as nursery areas for marine species and as permanent habitat for estuarine species. A 12-year data set of the aquatic macrofauna (fish, decapod and mysid crustaceans) in a Mediterranean estuary (Guadalquivir estuary, South Spain) was analysed to test if water scarcity favours the nursery function of regional estuaries to the detriment of permanent estuarine inhabitants. Target species typically displayed a salinity-related distribution and estuarine salinisation in dry years resulted in a general upstream community displacement. However, annual densities of marine species were neither consistently higher in dry years nor estuarine species during wet years. Exceptions included the estuarine mysid Neomysis integer and the marine shrimp Crangon crangon, which were more abundant in wet and dry years, respectively. High and persistent turbidity, a collateral effect of water scarcity, altered both the structural (salinity-related pattern) and functional (key prey species and predator density) community characteristics, chiefly after the second drought period of the analysis. The observed high inter-year environmental variability, as well as species-specific effects of water scarcity, suggests that exhaustive and long-term sampling programmes will be required for rigorously monitoring the estuarine communities of the Mediterranean-climate region. PMID:25005237

  13. Facilitation of the Estuary/Ocean Subgroup for Research, Monitoring, and Evaluation, FY07 Annual Report

    Energy Technology Data Exchange (ETDEWEB)

    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.

  14. Facilitation of the Estuary/Ocean Subgroup for Research, Monitoring and Evaluation - FY07 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    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.

  15. Pollution history of the Savannah Estuary. National status and trends program for marine environmental quality

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, C.; Ertel, J.; Lee, R.; Loganathan, B.; Martin, J.

    1997-09-01

    Dated cores collected from different sites in the Savannah Estuary were analyzed for 16 metals, 22 polycyclic aromatic hydrocarbons (PAH), 20 polychlorinated biphenyls (PCB) congeners, 16 pesticides and 3 butylins. Time stratigraphy of the cores were determined by measurements of Pb-210 and Cs-137 activities down the cores. Those chemicals which showed significant temporal changes down dated cores in the Savannah Estuary included mercury, lead, chromium, PAHs, DDT isomers and metabolites, PCBs and dieldrin. The present study used cores from the Savannah Estuary, where the population is relatively low (approximately 150,000) and industrial growth has occurred over the past 30 years. Thus, the concentrations of most anthropogenic chemical found in the cores of the Savannah Estuary were comparatively low. An interesting aspect of the study, which has been noted by many pollution history studies, was the decrease in the concentration of anthropogenic chemicals during the past two decades suggesting that many pollution control laws have been effective, even while industrial and population growth continues in an area. In summation, the authors` studies present evidence of relatively large inputs of anthropogenic chemicals, including mercury, chromium, lead, polycycloic aromatic hydrocarbons, dieldrin, DDT isomers, and polychlorinated biphenyls, during the 1950s and 1960 into the Savannah Estuary followed by a gradual decrease of these chemicals during the past 20 to 30 years.

  16. Dissimilatory nitrate reduction processes and associated contribution to nitrogen removal in sediments of the Yangtze Estuary

    Science.gov (United States)

    Deng, Fengyu; Hou, Lijun; Liu, Min; Zheng, Yanling; Yin, Guoyu; Li, Xiaofei; Lin, Xianbiao; Chen, Fei; Gao, Juan; Jiang, Xiaofen

    2015-08-01

    Dissimilatory nitrate reduction processes, including denitrification, anaerobic ammonium oxidation (ANAMMOX), and dissimilatory nitrate reduction to ammonium (DNRA), play an important role in controlling the nitrate dynamics and fate in estuarine and coastal environments. We investigated potential rates of denitrification, ANAMMOX, and DNRA in the sediments of the Yangtze Estuary via slurry incubation experiments combined with isotope-tracing techniques to reveal their respective contributions to total nitrate reduction in this hypereutrophic estuarine ecosystem. Measured rates of denitrification, ANAMMOX, and DNRA ranged from 0.06 to 4.51 µmol N kg-1 h-1, 0.01 to 0.52 µmol N kg-1 h-1, and 0.03 to 0.89 µmol N kg-1 h-1, respectively. These potential dissimilatory nitrate reduction process rates correlated significantly with salinity, sulfide, organic carbon, and nitrogen. Denitrification contributed 38-96% total nitrate reduction in the Yangtze Estuary, as compared to 3-45% for DNRA and 1-36% for ANAMMOX. In total, the denitrification and ANAMMOX processes removed approximately 25% of the external inorganic nitrogen transported annually into the estuary. In contrast, most external inorganic nitrogen was retained in the estuary and contributes substantially to the severe eutrophication of the Yangtze Estuary.

  17. Fingerprinting of bed sediment in the Tay Estuary, Scotland: an environmental magnetism approach

    Directory of Open Access Journals (Sweden)

    P. A. Jenkins

    2002-01-01

    Full Text Available Sediment fingerprinting is commonly used for sediment provenance studies in lakes, rivers and reservoirs and on hillslopes and floodplains. This investigation explores the mixing of terrestrial and marine-derived sediment in the Tay Estuary, Scotland, using mineral magnetic attributes for fingerprinting. Samples representative of the estuary sediments and of four sources (end-members were subjected to a suite of magnetic susceptibility and remanence measurements. Sediment samples from the beds of the Rivers Tay and Earn represented fluvial inputs while samples from the Angus and Fife coasts represented marine input. Multivariate discriminant and factor analysis showed that the sources could be separated on the basis of six magnetic parameters in a simple multivariate unmixing model to identify source contributions to estuarine bed sediments. Multi-domain magnetite signatures, characteristic of unweathered bedrock, dominate the magnetic measurements. Overall contributions of 3% from the River Earn, 17% from the River Tay, 29% from the Angus coast and 51% from the Fife coast source end-members, demonstrated the present-day regime of marine sediment derivation in the Tay Estuary. However, this conceals considerable spatial variability both along-estuary and in terms of sub-environments, with small-scale variations in sediment provenance reflecting local morphology, particularly areas of channel convergence. Keywords: bed sediment, environmental magnetism, fingerprinting, Tay Estuary, Scotland

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

    International Nuclear Information System (INIS)

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

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

    Directory of Open Access Journals (Sweden)

    Geddada Mohan NARASIMHA RAO

    2010-12-01

    Full Text Available Mangroves are highly productive ecosystems occurs intertidal regions only. Mangroves and associated flora occurring in two major estuaries of Godavari river (India were studied using transect with 4x4 m2 quadrats and the quadrat samples were analyzed. Seasonal data were collected on environmental, hydrographical and chemical observations from three different stations of the two estuaries. Low values in Secchi depth, salinity and pH were reported during the monsoon season, while higher values were reported in pre-monsoon and post monsoon seasons. In the present study three mangrove species and nine associated species were reported. Transect studies in these two estuaries showed that mangrove and halophytes occurred up to 40 meters from water front region. In some places mangrove vegetation was in the form of long strips only. In Vainateyam estuary, the species with the highest density was Suaeda monoica whereas the species with lowest density was Avicennia officinalis. In Vashista estuary, maximum density was reported for Suaeda maritima and minimum density for Avicennia officinalis. The maximum height in these two stations varied from 5 to 8 meters only. Percentage frequencies of DBH (Density at Breast Height classes were estimated. In the present study only two diameter classes were reported. This is indicative of the small and bushy mangrove vegetation in the region studied. Human interference, urban settlements and aqua industry play a critical impact on the survival of these tropical ecosystems. If management and conservation programmes are not undertaken, these ecosystems may be depleted.

  20. Squid as nutrient vectors linking Southwest Atlantic marine ecosystems

    Science.gov (United States)

    Arkhipkin, Alexander I.

    2013-10-01

    Long-term investigations of three abundant nektonic squid species from the Southwest Atlantic, Illex argentinus, Doryteuthis gahi and Onykia ingens, permitted to estimate important population parameters including individual growth rates, duration of ontogenetic phases and mortalities. Using production model, the productivity of squid populations at different phases of their life cycle was assessed and the amount of biomass they convey between marine ecosystems as a result of their ontogenetic migrations was quantified. It was found that squid are major nutrient vectors and play a key role as transient 'biological pumps' linking spatially distinct marine ecosystems. I. argentinus has the largest impact in all three ecosystems it encounters due to its high abundance and productivity. The variable nature of squid populations increases the vulnerability of these biological conveyers to overfishing and environmental change. Failure of these critical biological pathways may induce irreversible long-term consequences for biodiversity, resource abundance and spatial availability in the world ocean.

  1. Reservoir characterization of the Smackover Formation in southwest Alabama

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  4. A review of land-sea coupling by groundwater discharge of nitrogen to New England estuaries: Mechanisms and effects

    International Nuclear Information System (INIS)

    Hydrologists have long been concerned with the interface of groundwater flow into estuaries, but not until the end of the last century did other disciplines realize the major role played by groundwater transport of nutrients to estuaries. Mass balance and stable isotopic data suggest that land-derived NO3, NH4, and dissolved organic N do enter estuaries in amounts likely to affect the function of the receiving ecosystem. Because of increasing human occupancy of the coastal zone, the nutrient loads borne by groundwater have increased in recent decades, in spite of substantial interception of nutrients within the land and aquifer components of watersheds. Groundwater-borne nutrient loads have increased the N content of receiving estuaries, increased phytoplankton and macroalgal production and biomass, decreased the area of seagrasses, and created a cascade of associated ecological changes. This linkage between land use and eutrophication of estuaries occurs in spite of mechanisms, including uptake of land-derived N by riparian vegetation and fringing wetlands, 'unloading' by rapid water removal, and direct N inputs to estuaries, that tend to uncouple the effects of land use on receiving estuaries. It can be expected that as human activity on coastal watersheds continues to increase, the role of groundwater-borne nutrients to the receiving estuary will also increase

  5. MAPPING SEAGRASS AND GREEN MACROALGAE DISTRIBUTIONS IN AN OREGON ESTUARY USING COLOR INFRARED AERIAL PHOTOGRAPHY: 1997 & 1998

    Science.gov (United States)

    Aerial photograph surveys of Oregon's Yaquina Bay estuary were conducted during the summers of 1997 and 1998. Advantage was taken of daylight low tide conditions when most of the intertidal mudflats in the estuary were exposed. The absence of overlying water permitted the use o...

  6. MAPPING SEAGRASS AND GREEN MACROALGAE DISTRIBUTIONS IN AN OREGON ESTUARY USING COLOR-INFRARED AERIAL PHOTOGRAPHY: 1997 & 1998

    Science.gov (United States)

    Aerial photograph surveys of Oregon's Yaquina Bay estuary were conducted during the summers of 1997 and 1998. Advantage was taken of daylight low tide conditions when most of the intertidal mudflats in the estuary were exposed. The absence of overlying water permitted the use o...

  7. Facilitation of the Estuary/Ocean Subgroup for Federal Research, Monitoring and Evaluation FY08 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, GE; Diefenderfer, HL [Pacific Northwest National Laboratory

    2008-09-29

    The Estuary/Ocean Subgroup (EOS) is part of the research, monitoring, and evaluation (RME) effort that the Action Agencies (Bonneville Power Administration (BPA), U.S. Army Corps of Engineers, U.S. Bureau of Reclamation) developed in response to obligations arising from the Endangered Species Act as applied to 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 fiscal year 2008 (FY08), 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 BPA's project tracking system, Pisces; (4) quarterly project status reports; and (5) a major revision to the Estuary RME document and its subsequent regional release (new version January 2008). Many of the estuary RME recommendations in this document were incorporated into the Biological Opinion on FCRPS operations (May 2008). In summary, the FY08 EOS project resulted in expanded, substantive coordination with other regional RME forums, a new version of the federal Estuary RME program document, and implementation coordination. This annual report is a FY08 deliverable for the project titled Facilitation of the Estuary/Ocean Subgroup.

  8. Facilitation of the Estuary/Ocean Subgroup for Federal Research, Monitoring, and Evaluation, FY08 Annual Report

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Gary E.; Diefenderfer, Heida L.

    2008-09-29

    The Estuary/Ocean Subgroup (EOS) is part of the research, monitoring, and evaluation (RME) effort that the Action Agencies (Bonneville Power Administration, U.S. Army Corps of Engineers, U.S. Bureau of Reclamation) developed in response to obligations arising from the Endangered Species Act as applied to 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 fiscal year 2008 (FY08), 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 document and its subsequent regional release (new version January 2008). Many of the estuary RME recommendations in this document were incorporated into the Biological Opinion on hydrosystem operations (May 2008). In summary, the FY08 EOS project resulted in expanded, substantive coordination with other regional RME forums, a new version of the federal Estuary RME program document, and implementation coordination. This annual report is a FY08 deliverable for the project titled Facilitation of the Estuary/Ocean Subgroup.

  9. 76 FR 9709 - Water Quality Challenges in the San Francisco Bay/Sacramento-San Joaquin Delta Estuary

    Science.gov (United States)

    2011-02-22

    ...Delta Estuary water quality stressors, and water quality regulatory and non-regulatory...better protect and improve water quality for the benefit of...are under serious stress. All of the waters...Delta Estuary and to work with the State...

  10. Flood/ebb tidal asymmetry in a shallow sandy estuary and the impact on net sand transport

    Science.gov (United States)

    Brown, J. M.; Davies, A. G.

    2010-01-01

    Flood/ebb tidal dominance plays a pivotal role in estuarine sediment transport. The Dyfi Estuary, mid-Wales, UK, is used as a case study, together with an idealized trumpet-shaped estuary morphology, to illustrate key processes giving rise to flood/ebb dominance. Observations made in the main entrance channel to the Dyfi indicate that the system is presently ebb-dominant with regard to both the relatively long duration of the ebb tide and also the faster ebb velocities. Predictions made across the mouth of the estuary using the Telemac Modelling System suggest further that the net sand transport presently occurs out of the estuary. In contrast, due to the varying distribution of channels and flats within the estuary, the tidal flow in the upper estuary is flood-asymmetric and here the net transport is up-estuary. Flood versus ebb dominance is shown to be attributable to the relative extent of the channels and sandflats in relation to the mean water level. An attempt is made to develop a simple metric to determine present-day transport pathways within an estuary in response to its cross-channel flow asymmetries.

  11. Allochthonous Organic Matter Subsidize the High Secondary Production of the Invasive Bivalve Corbicula fluminea in Minho Estuary (N-Portugal)

    Science.gov (United States)

    The Asian clam Corbicula fluminea is one of the most invasive species in freshwater ecosystems. In Minho estuary, this species colonize all the middle and upper part of the estuary, dominating the abundance, biomass and secondary production in River Minho tidal freshwater area (T...

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

    Directory of Open Access Journals (Sweden)

    C. Bovalo

    2012-08-01

    Full Text Available The World Wide Lightning Location Network (WWLLN data have been used to perform a lightning climatology in the South-West Indian Ocean (SWIO region from 2005 to 2011. Maxima of lightning activity were found in the Maritime Continent and southwest of Sri Lanka (>50 fl km?2 yr?1 but also over Madagascar and above the Great Lakes of East Africa (>10–20 fl km?2 yr?1. Lightning flashes within tropical storms and tropical cyclones represent 50 % to 100 % of the total lightning activity in some oceanic areas of the SWIO (between 10° S and 20° S.

    The SWIO is characterized by a wet season (November to April and a dry season (May to October. As one could expect, lightning activity is more intense during the wet season as the Inter Tropical Convergence Zone (ITCZ is present over all the basin. Flash density is higher over land in November–December–January with values reaching 3–4 fl km?2 yr?1 over Madagascar. During the dry season, lightning activity is quite rare between 10° S and 25° S. The Mascarene anticyclone has more influence on the SWIO resulting in shallower convection. Lightning activity is concentrated over ocean, east of South Africa and Madagascar.

    A statistical analysis has shown that El Niño–Southern Oscillation mainly modulates the lightning activity up to 56.8% in the SWIO. The Indian Ocean Dipole has a significant contribution since ~49% of the variability is explained by this forcing in some regions. The Madden–Julian Oscillation did not show significative impact on the lightning activity in our study.

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

    Scientific Electronic Library Online (English)

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

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

  14. Radioactivity and United Kingdom estuaries: an overview identifying research priorities

    International Nuclear Information System (INIS)

    The report consists of the results of an evaluation of research priorities for the environmental radioactivity of estuaries, (and near shore waters) of the United Kingdom. The format of this report is:(i) general conclusions for the future requirements for research in the field of environmental radioactivity; (ii) an overview of some specific recommendations for research; and (iii) an appendix in which a comprehensive evaluation of the research priorities for specific areas of research are given. On the basis that man is the prime target for concern and protection, special attention has been given to the environment in the vicinity of the British Nuclear Fuels (BNFL) reprocessing plant at Sellafield, Cumbria, which is the source of major releases of a variety of radionuclides into the natural environment. Subjects covered in the Appendix are: site factors; pathways to man; source term; hot particles; terrestrial inputs; surveys and monitoring; analysis; organics; field versus laboratory data; biology; bioaccumulation factors; some bioaccumulators of radioactivity; bioturbation; bacteria; genetics; natural change; sediment; resuspension; surfaces; Ksub(d) factors; pore liquids; diagenesis and the ageing processes; airborne transport of radionuclides; models; natural radioactivity; public opinion; recreation; the ICRP; the ALARA principle; decommissioning of nuclear power stations; identification of research requirements; environmental radioactivity - the national effort. (U.K.)

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

    Energy Technology Data Exchange (ETDEWEB)

    U.S. Bonneville Power Administration

    2008-08-01

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

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

    International Nuclear Information System (INIS)

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

  17. An overview of tritium behaviour in the Severn Estuary (UK)

    International Nuclear Information System (INIS)

    Measurements of tritium (3H) activity in marine species in the Severn Estuary (UK) show concentrations significantly above those predicted by standard models. Concentration factors of 104 between seawater and marine species are observed; standard models assume a concentration factor of 1. In addition, the vast majority of activity is present in the form of organically bound tritium (OBT). The critical group dose from tritium - to consumers of local flounder - is estimated as ?36 ?Sv per annum. The measurements are related to the authorised release of wastes, via the sewer system, from the Amersham plc plant at Cardiff. The radiochemical plant manufactures a wide range of isotopically labelled compounds for use in life science research. The elevated levels of tritium observed in marine species have led to a programme of investigative work by specialist organisations. This paper describes the various definitions, measurements and significance of the term OBT. It also outlines the environmental observations and preliminary conclusions from the investigative programme to date. (author)

  18. Plutonium AMS measurements in Yangtze River estuary sediment

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-04-15

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

  19. Plutonium AMS measurements in Yangtze River estuary sediment

    International Nuclear Information System (INIS)

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

  20. Measuring hydrodynamics and sediment transport processes in the Dee Estuary

    Directory of Open Access Journals (Sweden)

    R. Bolaños

    2010-06-01

    Full Text Available The capability of monitoring and prediction in the marine environment provides information that may allow sustainable development of coastal and offshore regions. Therefore, the continuous measurement of environmental processes becomes an important source of information. The present paper shows data collected during 6 years, and in particular during 2008, in the Dee Estuary. The aim of the data collection is to improve the observations of the mobile sediments in coastal areas and its forcing hydrodynamics and turbulence. Data includes information from the deployment of instrumented rigs measuring sediment in suspension, currents, waves, sea level, sediment size and bedforms as well as cruise work including grab sampling, CTD profiles and side-scan sonar. The data cover flood and ebb tides during spring and neap periods with moderate and mild wave events, thus, having a good coverage of the processes needed to improve knowledge of sediment transport and the parameterizations used in numerical modelling. The data, in raw and treated, are being banked at BODC (British Oceanographic Data Centre, http://www.bodc.ac.uk/ which is the formal British organization for looking after and distributing data concerning the marine environment.

  1. Measuring hydrodynamics and sediment transport processes in the Dee estuary

    Directory of Open Access Journals (Sweden)

    R. Bolaños

    2010-03-01

    Full Text Available The capability of monitoring and predicting the marine environment leads to a more sustainable development of coastal and offshore regions. Therefore, the continuous measurement of environmental processes become an important source of information. The present paper shows data collected during 6 years, and in particular during 2008, in the Dee Estuary. The data aims to improve the observations of the mobile sediments in coastal areas and its forcing hydrodynamics and turbulence. Data involves the deployment of instrumented rigs measuring sediment in suspension, currents, waves, sea level, sediment size and bedforms as well as cruise work including grab sampling, CTD profiles and side-scan sonar. The data covers flood and ebb tides during spring and neap periods with moderate and mild wave events, thus, having a good coverage of the processes needed to improve knowledge of sediment transport and the parameterizations used in numerical modelling. The data, in raw and treated, is being banked at BODC (British Oceanographic Data Centre, http://www.bodc.ac.uk/ which is the formal British organization for looking after and distributing data concerning the marine environment.

  2. [Niche of macrozoobenthos in intertidal zone of Jiaojiang Estuary].

    Science.gov (United States)

    Zhao, Yong-Qiang; Zeng, Jiang-Ning; Gao, Ai-Gen; Chen, Quan-Zhen; Shou, Lu; Liao, Yi-Bo; Huang, Yi-Jun

    2009-05-01

    The niche width and niche overlap of macrozoobenthos dominant species in the intertidal zone of Jiaojiang Estuary in October 2007 were analyzed based on niche theory, and the effects of natural factors (salinity, water temperature, sediment temperature, beach width, and sediment grain size) and environmental factors (contents of oils and heavy metals) on the environmental heterogeneity as well as the relationships between selected environmental factors and quantitative distribution of various groups of macrozoobenthos were studied by using canonical correspondence analysis method. The macrozoobenthos dominant species in study area were classified into four groups, i. e., burrowing surface predator, surface grazer, subsurface filter feeder, and subsurface swallow feeder, based on their feeding types. There were great differences in the niche widths among the groups, with the maximum of 0.428 and the minimum of 0.168, which suggested that different groups had different adaptive capacity to the environmental factors. At the level of niche overlap value higher than 0.6, Macrophthalmus japonicas and M. definitus of Group 1, Lunatica gilva, Bullacta exarata, Decorifera insignis, Assiminea brevicula and Cerithidae ornate of Group 2, and Moerella iridescens, Glauconome chinensis and Potamocorbula laevis of Group 3 had a biologically significant niche overlap, indicating their similar behavior in utilizing natural feeding resources. PMID:19803178

  3. Southwest Center for Environmental Excellence and Opportunity Year End Report (Final Deliverable)

    Energy Technology Data Exchange (ETDEWEB)

    None

    1998-11-09

    The Southwest Center for Environmental Excellence and Opportunity (Southwest CEEO) has been in existence since October 1996 at Albuquerque Technical Vocational Institute's (TVI) South Valley Campus. The Special Project was comprised of three objectives: (1) Increasing the number of Hispanics in careers related to the environment by improving education and job training opportunities; (2) Strengthening the infrastructure of Hispanic businesses and building their capacity to participate in environmental clean-up activities and potential technology commercialization; and (3) Increasing the Hispanic community's understanding of and participation in environmental protection through improved access to information and outreach activities, paying attention to cultural and linguistic issues. The Southwest CEEO has been successful in each of the above objective areas and continues to provide valuable services to TVI and the community. The Southwest CEEO has developed a scholarship/mentorship program involving business and industry, community organizations, and TVI faculty that will be replicated by other student mentorship programs. The Southwest CEEO has awarded approximately $50,000 over the two-year program funded by the U.S. Department of Energy Oakland Operations Office. The Southwest CEEO has also developed a K-12 partnership with Albuquerque Public Schools (APS) to enhance environmental education for students and professional development for teachers. Incorporated into these student activities are experimental learning opportunities and curriculum development and/or enhancement. The Southwest CEEO has worked closely with the TVI Small Business Development Center (SBDC) to support Hispanic businesses in technology partnership activities. The Southwest CEEO in partnership the TVI SBDC has provided a large business forum and business workshops. In addition, the Southwest CEEO has developed a Technology Transfer Model that will be expanded in the future to a technology transfer guide to be used by New Mexico SBDC's. The Southwest CEEO has been active in the Albuquerque South Valley Community and Bernalillo County to promote more Hispanic community participation in environmental issues and education opportunities. The Southwest CEEO has hosted community environmental forums, workshops, and conferences. The Southwest CEEO is also participating on the Bernalillo County Environmental Health Department Technology Deployment Initiative Advisory committee, Hispanic Statement of Cooperation Group, and the Groundwater Protection and Action Plan (GPAP) Committee.

  4. Environmental controls on the speciation and distribution of mercury in surface sediments of a tropical estuary, India.

    Science.gov (United States)

    Chakraborty, Parthasarathi; Babu, P V Raghunadh

    2015-06-15

    Distribution and speciation of mercury (Hg) in the sediments from a tropical estuary (Godavari estuary) was influenced by the changing physico-chemical parameters of the overlying water column. The sediments from the upstream and downstream of the estuary were uncontaminated but the sediments from the middle of the estuary were contaminated by Hg. The concentrations of Hg became considerably less during the monsoon and post monsoon period. Total Hg concentrations and its speciation (at the middle of the estuary) were dependent on the salinity of the overlying water column. However, salinity had little or no effect on Hg association with organic phases in the sediments at downstream. Increasing pH of the overlying water column corresponded with an increase in the total Hg content in the sediments. Total organic carbon in the sediments played an important role in controlling Hg partitioning in the system. Uncomplexed Hg binding ligands were available in the sediments. PMID:25935803

  5. Ostracoda and foraminifera as short-term tracers of environmental changes in very polluted areas: the Odiel Estuary (SW Spain)

    International Nuclear Information System (INIS)

    The analysis of 17 cores collected in the Odiel Estuary (SW Spain) permits delimiting the recent evolution of this zone during the past decades and the influence of natural and anthropogenic factors on the distribution of Ostracoda and Foraminifera. In the upper estuary, the coincidence of acid waters, prolonged subaerial exposure, and coarse sediments may explain the absence or the disappearance of these microorganisms during the industrial period (1966-1985) in the major part of this area. In the lower estuary, sedimentary evolution and industrial wastes are the main factors influencing both the distribution and trends of the populations of these two groups. Finally, the main changes observed in the marine estuary are due to the sedimentary effects of the construction of two banks and the dredging of the main estuarine channel. - In a polluted estuary, the meiofaunal assemblages experience different changes even in adjacent sedimentary environments, closely related to anthropogenic and natural causes

  6. User's guide and metadata for WestuRe: U.S. Pacific Coast estuary/watershed data and R tools

    Science.gov (United States)

    Frazier, M.R.; Reusser, D.A.; Lee, H., II; McCoy, L.M.; Brown, C.; Nelson, W.

    2013-01-01

    There are about 350 estuaries along the U.S. Pacific Coast (U.S. Fish andWildlife 2011). Basic descriptive data for these estuaries, such as their size and watershed area, are important for coastal-scale research and conservation planning. However, this information is spread among many sources, making it difficult to find and standardize. The goal of the WestuRe Project is to provide a framework to: (1) make general descriptive data for estuaries and their watersheds more accessible, and (2) provide tools to make analyzing and visualizing these data easier. The WestuRe download includes data describing U.S. Pacific Coast estuaries and their corresponding watersheds from northern Washington (including the region located along the Strait of Juan de Fuca that goes from Port Townsend to Cape Flattery, 48.383°N) to southern California (Tijuana Estuary,

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

    Directory of Open Access Journals (Sweden)

    Steven M. Wu

    2012-09-01

    Full Text Available The expansion of Southwest Airlines and JetBlue Airways has sparked new empirical interest in the effects of low-cost carriers (LCC on existing airfares. Namely, empirical studies have attempted to capture the threat, or potential competition, of an entrant. This paper examines incumbent airline prices as a result of potential and actual competition from both Southwest Airlines and JetBlue Airways from 1993 to 2009 by analyzing mean airfares as well as price dispersion on incumbent routes. I incorporate a panel OLS with fixed effects model as well as GLS model with random effects. Consistent with re-cent literature, this paper finds that legacy incumbents cut fares significantly when threatened by Southwest Airlines. However, low-cost incumbents do not exhibit the same magnitude of pre-emptive price cutting. When threatened by JetBlue, neither legacy nor low-cost carriers cut fares significantly, suggest-ing that incumbents react differently when threatened by Southwest versus JetBlue. The evidence of increased price dispersion is mixed with price dis-persion decreasing on legacy carrier routes as a result of Southwest threat and entry but increasing on legacy carrier routes as a result of JetBlue threat and entry.

  8. Identification of the toxic constituents of sediments in a Brazilian subtropical estuary.

    Science.gov (United States)

    Poleza, Fernanda; Souza, Rafael C; Resgalla, Charrid

    2014-03-15

    Phase 1 of the TIE method was applied to samples of elutriates from sediments of the Itajaí-Açu estuary and adjacent coastal region in southern Brazil. Embryo-larval toxicity assays were used with the sea urchin Arbacia lixula in samples of raw elutriate, and treated with Ulva fasciata, EDTA and sodium thiosulfate. Inside the estuary, ammonia was responsible for more than 40% of the toxicity in both the dredged and undredged regions. A toxicity gradient was observed, between the estuary and the coastal region, with an increase in the importance of metals for the latter. Temporally, there is strong evidence of the influence of dredging and disposal of sediments in the contamination of the coastal dumping site. The results indicating that this area presents limitations in its saturation capacity. Chemical analysis indicated the metal Cu is probably responsible for the toxicity of the sediments observed, without the interference of ammonia. PMID:24503379

  9. Variability in waterfowl distribution within hypertidal estuaries in relation to sediments

    International Nuclear Information System (INIS)

    The Severn and Mersey estuaries are two of Britain's most important sites for their waterfowl populations. It is therefore critical to fully understand the likely impacts of tidal power barrages on these populations in order to predict the long-term post-barrage populations that the estuaries could support. Previous studies have enabled four years of monitoring to be carried out on both estuaries using identical methodology. These studies have shown that there is a considerable degree of consistency in the waterfowl populations in some areas, although apparently less so in other areas. Studies of sediment mobility have not been carried out in ways which enable direct comparison of changes in sediment with changes in bird populations. This latest study was planned to permit such a comparison and to provide five years of detailed counts on the Severn and four years on the Mersey on the low tide distribution of waterfowl populations. (author)

  10. Distribution, transport and exchanges of fine sediment, with tidal power implications: Severn Estuary, UK.

    Science.gov (United States)

    Kirby, R

    2010-01-01

    The Severn, a hypertidal, high turbidity estuary, has a bed largely stripped of unconsolidated sediment. Its inter-tidal zone is mainly mudflats, the universal erosional trend of which is now proven. These are a source for sub-tidal mud accumulations in Newport Deep, much of Bridgwater Bay, less so in Bristol Deep and Cardiff Roads. The main estuary turbidity maximum is dominated by its exceptional turbidity and the cycling of this on two tidal timescales. It is the means to exchange fines between sources and sinks. It shows discontinuities in three planes - lutoclines, suspended sediment fronts and slug flow. Much of the estuary is verging on or actually barren. It has been designated under EU legislation for its fine sediment-induced naturally-depauperate nature. This is invalid as it is complicated by large scale ecosystem collapse due to climate change. Building a Cardiff-Weston barrage would induce a large rise in faunal abundance and biodiversity. PMID:20153483

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

    International Nuclear Information System (INIS)

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

  12. Nutrient Enrichment in Estuaries from Discharge of Shallow Ground Water, Mt. Desert Island, Maine

    Science.gov (United States)

    Culbertson, Charles W.; Huntington, Thomas G.; Caldwell, James M.

    2007-01-01

    Nutrient enrichment from atmospheric deposition, agricultural activities, wildlife, and domestic sources is a concern at Acadia National Park because of the potential problem of water-quality degradation and eutrophication in its estuaries. Water-quality degradation has been observed at the Park?s Bass Harbor Marsh estuary but not in Northeast Creek estuary. Previous studies at Acadia National Park have estimated nutrient inputs to estuaries from atmospheric deposition and surface-water runoff, but the importance of shallow ground water that may contain nutrients derived from domestic or other sources is unknown. Northeast Creek and Bass Harbor Marsh estuaries were studied to (1) identify shallow ground-water seeps, (2) assess the chemistry of the water discharged from selected seeps, and (3) assess the chemistry of ground water in shallow ground-water hyporheic zones. The hyporheic zone is defined here as the region beneath and lateral to a stream bed, where there is mixing of shallow ground water and surface water. This study also provides baseline chemical data for ground water in selected bedrock monitoring wells and domestic wells on Mt. Desert Island. Water samples were analyzed for concentrations of nutrients, wastewater compounds, dissolved organic carbon, pH, dissolved oxygen, temperature and specific conductance. Samples from bedrock monitoring wells also were analyzed for alkalinity, major cations and anions, and trace metals. Shallow ground-water seeps to Northeast Creek and Bass Harbor Marsh estuaries at Acadia National Park were identified and georeferenced using aerial infrared digital imagery. Monitoring included the deployment of continuously recording temperature and specific conductance sensors in the seep discharge zone to access marine or freshwater signatures related to tidal flooding, gradient-driven shallow ground-water flow, or shallow subsurface flow related to precipitation events. Many potential shallow ground-water discharge zones were identified from aerial thermal imagery during flights in May and December 2003 in both estuaries. The occurrence of ground-water seeps was confirmed using continuous and discrete measurements of temperature and specific conductance in selected seeps and in the adjacent estuaries that showed salinity anomalies reflecting the input of freshwater in these complex tidal systems. Analysis of water samples from shallow ground water in the hyporheic zone and from ground-water seeps indicated the presence of elevated concentrations of dissolved nitrogen, compared to concentrations in the adjacent estuaries and surface-water tributaries draining into the estuaries. These findings indicate that shallow ground water is a source of dissolved nitrogen to the estuaries. Orthophosphate levels were low in ground water in the hyporheic zone in Bass Harbor Marsh, but somewhat higher in one hyporheic-zone well in Northeast Creek compared with the concentrations in both estuaries that were at or below detection limits. Household wastewater-related compounds were not detected in ground water in the hyporheic zone. Analysis of water samples from domestic and bedrock monitoring wells developed in fractured bedrock indicated that concentrations of dissolved nitrogen, phosphorus, and household wastewater-related compounds were typically at or below detection, suggesting that the aquifers sampled had not been contaminated from septic sources.

  13. PSE and G's Estuary Enhancement Program restoration of the Dennis Township Salt Hay Farm

    International Nuclear Information System (INIS)

    In July 1994, the New Jersey Department of Environmental Protection (NJDEP) issued a final New Jersey Pollutant Discharge Elimination System Permit for Public Service Electric and Gas Company's (PSE and G) Generating System. This permit included several special conditions that addressed concerns about loss of aquatic organisms resulting from the Station's once-through cooling system and the potential impacts to the sustained health of the Delaware Estuary ecosystem. One special condition was to restore, enhance, and preserve a minimum of 8,000 acres of degraded wetlands along the Delaware Estuary. PSE and G's Estuary Enhancement Program is the largest salt marsh restoration project in the US. This project will significantly increase the number of acres of health, salt marsh along the Delaware River, will greatly increase the available habitat for fish production, and will increase the green space available to the public for varied recreational and educational uses

  14. Social foraging and feeding environment of the black-crowned night heron in an industrialized estuary

    Science.gov (United States)

    Erwin, R.M.; Hatfield, J.S.; Link, W.A.

    1991-01-01

    A nesting colony of more than 300 pairs of Black-crowned Night-Herons in the Patapsco River estuary, Baltimore Harber, Maryland was monitored from May to July 1988. The departure direction and departure time of each Heron was recorded during mornjng and evening observations at the colony. In addition, individual Herons were followed to landing sites in the estuary with small boats and aircraft. Herons appear to be quite social in foraging and may concentrate their feeding in some of the most industrialized parts of the estuary. Night-Herons may prosper in urban environments because some of their prey are attracted to intense shoreline illumination at night. New quantitative methods were developed to cope with the lack of statistical independence when dealing with social species.

  15. Trace metals in the estuary of the Seine and its approaches

    International Nuclear Information System (INIS)

    The distribution and behaviour of trace metals (Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Ti, V and Zn) were studied in the waters and deposited or suspended sediments of the estuary and eastern bay of the Seine river. The various physico-chemical forms - hydrosoluble, exchangeable, chelated, organic forms, were determined by successive fractionations. The abundance of the ionic stock in the estuary cannot explain the decrease of trace metal contents by purely chemical processes. Mixing processes with open sea particles and release of metals induced by the erosion-sedimentation cycles resulting in sediment washing can explain the observations. Metals first trapped in the sediments are freed in the dissolved state; they can be expelled from the estuary and participate in the biological cycles. In the bay sediments, the trace metals were used as tracers of sediment masses, allowing to determine the river deposit areas. The human contribution to trace metal deposits in the Seine river bay was also estimated. (author)

  16. Sessile ciliates on artificial substrata submerged in a polluted estuary (Santos, SP, Brazil

    Directory of Open Access Journals (Sweden)

    Verena Rapp de Eston

    1985-01-01

    Full Text Available Primary growth was analysed on artificial substrata submerged at three sites of the Santos estuary (State of São Paulo, Brazil. Research on sessile ciliates was emphasized because they were the most conspicuous organisms of the primary growth developed along this estuary. Zoothamnium commune, dominated near the headwaters of the estuary, where the greatest amount of suspended matter in the water was found. Ephelota gemmipara dominated downstream. Although short time variability was observed in the colonization of substrata submerged on subsequent days, seasonal patterns could be determined. These patterns were characterized by a greater number of rare species of sessile ciliates, and a higher density of the most frequent ones, during spring and summer.

  17. Sessile ciliates on artificial substrata submerged in a polluted estuary (Santos, SP, Brazil)

    Scientific Electronic Library Online (English)

    Verena Rapp de, Eston.

    Full Text Available Primary growth was analysed on artificial substrata submerged at three sites of the Santos estuary (State of São Paulo, Brazil). Research on sessile ciliates was emphasized because they were the most conspicuous organisms of the primary growth developed along this estuary. Zoothamnium commune, domin [...] ated near the headwaters of the estuary, where the greatest amount of suspended matter in the water was found. Ephelota gemmipara dominated downstream. Although short time variability was observed in the colonization of substrata submerged on subsequent days, seasonal patterns could be determined. These patterns were characterized by a greater number of rare species of sessile ciliates, and a higher density of the most frequent ones, during spring and summer.

  18. Valuing environmental water pulses into the Incomati estuary: Key to achieving equitable and sustainable utilisation of transboundary waters

    Science.gov (United States)

    Sengo, D. José; Kachapila, Albert; Zaag, Pieter van der; Mul, Marloes; Nkomo, Sakhiwe

    Upstream developments in the Incomati river basin, shared by South Africa, Swaziland and Mozambique, have altered downstream flows significantly. The frequency of small floods into the estuary has been reduced dramatically. This change in the flow regime has impacted on the state of the environment downstream, and the Incomati estuary in particular. The estuary requires fresh water pulses that naturally occur, and the resulting seasonal flooding of the plains. Resource-poor rural households depend on the goods and services that the estuary and flood plains provide such as wood, charcoal, building materials, fish and shrimp, wetland farming, and tourism. Alteration of the flow regime into the estuary has a negative impact on the state of the environment and hence on the goods and services the estuary yields; a phenomenon the people living near the estuary are keenly aware of. The article estimates the value of the goods and services that the estuary currently provides, that is under the conditions of a changed flow regime. A linear relationship is then assumed between fresh water pulses into the estuary and the goods and services it provides, so that the order of magnitude of the economic value of fresh water pulses into the estuary may be approximated. Various development scenarios in the Incomati basin are then considered, that have different upstream and downstream impacts on water availability, and the basin-wide benefits and costs are compared. The paper concludes that the principle of sharing the benefits derived from the water resources, rather than the water itself, as proposed by authors such as [Sadoff, C.W., Grey, D., 2002. Beyond the river: the benefits of cooperation on international rivers. Water Policy 4, 389-403], may be a feasible approach only if the less tangible benefits and functions, especially those of the environment, are assigned an appropriate value and corresponding priority.

  19. Fate of sulfonamide resistance genes in estuary environment and effect of anthropogenic activities.

    Science.gov (United States)

    Lu, Zihao; Na, Guangshui; Gao, Hui; Wang, Lijun; Bao, Chenguang; Yao, Ziwei

    2015-09-15

    With the exacerbating problem of antibiotic resistance, antibiotic resistance genes (ARGs) as emerging contaminants are found at elevated levels in inland aquatic environments, especially in regions of intensive agricultural and urban activity. However, little quantitative data exist on the migration and attenuation of ARGs in estuary ecosystem, which is central to predicting their fate after release into marine environment. Moreover, the relevance of multiple chemical contaminants and water quality constituents should be understood to amplify and attenuate antibiotic resistance levels. To determine the prevalence and examine the fate of sulfonamide ARGs (sul-ARGs) in two estuaries under different effects of anthropogenic activities, we analyzed the sul-ARGs (sul1, sul2, and sul3), class 1 integrons (int1), and bacterial biomass in surface water samples from Daliaohe and Liaohe river estuaries. We also evaluated five types of antibiotics, heavy metals, and various bulk water quality constituents. Results showed that sul-ARGs were widespread in Daliaohe and Liaohe river estuaries, but the distribution did not correlate with the concentration of sulfonamides. Significant reduction in the abundance of sul-ARGs was also observed with increased salinity. Nevertheless, the trend in the change of concentrations of sul-ARGs was different in the two estuaries. Statistical analysis of the results indicated that several metals were significantly and positively correlated with sul-ARGs. Pearson's correlation coefficients were higher than those determined between antibiotic residues and sul-ARGs. Furthermore, the relative abundance of sul-ARGs was significantly and positively correlated with the relative abundance of int1 which suggested that the propagation of sul-ARGs was facilitated by class 1 integrons in estuaries. PMID:25981941

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

    Energy Technology Data Exchange (ETDEWEB)

    Diefenderfer, Heida L.; Thom, Ronald M.; Borde, Amy B.; Roegner, G. C.; Whiting, Allan H.; Johnson, Gary E.; Dawley, Earl; Skalski, John R.; Vavrinec, John; Ebberts, Blaine D.

    2006-12-20

    This report is the second annual report of a six-year project to evaluate the cumulative effects of habitat restoration projects in the Columbia River Estuary, conducted by Pacific Northwest National Laboratory's Marine Sciences Laboratory, NOAA's National Marine Fisheries Service Pt. Adams Biological Field Station, and the Columbia River Estuary Study Taskforce for the US Army Corps of Engineers. In 2005, baseline data were collected on two restoration sites and two associated reference sites in the Columbia River estuary. The sites represent two habitat types of the estuary--brackish marsh and freshwater swamp--that have sustained substantial losses in area and that may play important roles for salmonids. Baseline data collected included vegetation and elevation surveys, above and below-ground biomass, water depth and temperature, nutrient flux, fish species composition, and channel geometry. Following baseline data collection, three kinds of restoration actions for hydrological reconnection were implemented in several locations on the sites: tidegate replacements (2) at Vera Slough, near the city of Astoria in Oregon State, and culvert replacements (2) and dike breaches (3) at Kandoll Farm in the Grays River watershed in Washington State. Limited post-restoration data were collected: photo points, nutrient flux, water depth and temperature, and channel cross-sections. In subsequent work, this and additional post-restoration data will be used in conjunction with data from other sites to estimate net effects of hydrological reconnection restoration projects throughout the estuary. This project is establishing methods for evaluating the effectiveness of individual projects and a framework for assessing estuary-wide cumulative effects including a protocol manual for monitoring restoration and reference sites.

  1. Historic change in catchment land use and metal loading to Sydney estuary, Australia (1788-2010).

    Science.gov (United States)

    Birch, G F; Lean, J; Gunns, T

    2015-09-01

    Sydney estuary has a long history of environmental degradation and is one of the most modified water ways in Australia due to a highly urbanised catchment (~77 %) and a high population (4.6 million). The objectives of the present study were to map historical land use change from European settlement (1788) to 2010 to determine catchment evolutionary pathways and to estimate catchment loading (total suspended solids, Cu, Pb and Zn) to the estuary over this period. Land use distribution in Sydney catchment, determined for seven time horizons over this period, indicated that a substantial increase in residential land use through subdivision of large estates and an increase in road area resulted in a marked increase in metal loading to Sydney estuary between 1892 and 1936. The decline in industrial activity from a maximum in 1978 (3.9 %) to 1.8 % in 2010 and the introduction of unleaded fuel during this time was accompanied by reduction in metal loading to the estuary. Land use time horizon maps enabled the creation of novel, ternary diagrams to represent temporal evolution in catchment land use. The 15 sub-catchments of Sydney estuary were combined into three major catchment categories, i.e., urban, dense urban and commercial. Present-day annual discharge of stormwater from the Sydney catchment was calculated to be 466,000 ML and annual loadings of total suspended sediment (TSS), Cu, Pb and Zn in tonnes were 49,239, 27, 37 and 57, respectively. Stormwater has superseded industry as the main source of anthropogenic metals to this estuary in recent times. PMID:26311263

  2. Assessing habitat specific fish assemblages in estuaries along the Portuguese coast

    Science.gov (United States)

    França, Susana; Costa, Maria José; Cabral, Henrique N.

    2009-06-01

    Estuaries consist of a complex mosaic of many distinctive habitat types. Each one may perform several vital functions in the functioning of the whole system and although its value is often based on species density patterns, functional relationships between them also need to be examined. Spatial patterns of estuarine habitat use by fish assemblages were determined within and among nine estuarine systems along the Portuguese coast. Fish sampling surveys were conducted in May and July 2006, covering the full estuarine gradient. All the different habitat types were sampled in each estuarine system with a beam trawl. Estuarine habitats were mapped with GIS and habitat specific associated fish assemblages were described based on several community descriptors, namely richness ( S), evenness ( J'), and diversity ( H') and on an ecological and feeding guilds classification. A canonical correspondence analysis was performed to evaluate the relationship between estuarine habitats and fish assemblages in this set of estuaries. The intertidal and subtidal soft substratum habitats corresponded to the largest areas in all the estuaries and presented higher number of species. Nevertheless the highest mean density of fish was registered at the salt marsh habitat, which occupies smaller areas within each estuary. The fact that small vegetated habitats like salt marsh and seagrass supported high densities of fish may be an indication of the important role these habitats play in the whole system functioning. Differences in fish assemblage structure were found with latitude and between habitats amongst and within estuaries. Some of the fish species were found to be particularly associated with certain habitat types, which might indicate that each estuarine habitat may be related with specific fish assemblages regardless the estuary. The present work provides valuable information for management by identifying the most important habitats for species conservation and predicting the possible effects of habitat disturbance or destruction, namely by climate change and anthropogenic pressures.

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

    Science.gov (United States)

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

    2008-01-01

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

  4. STUDY ON THE EFFECTS OF TIDE ON SEDIMENTATION IN ESTUARIES OF THE NIGER DELTA, NIGERIA

    OpenAIRE

    Charles Chizom Dike; Jonah Chukwuma Agunwamba

    2012-01-01

    Niger Delta Estuary Nigeria is influenced by tidal currents due to its proximity to the Atlantic Ocean. Tides in the region are mostly semidiurnal, having two high and low water levels each day, with tidal prism ranging from 0.4 to 1.5m. The effects of tidal current reduces with distance inland and are strongest at the inlets with velocity varying from 2.0 to 5.0m/sec. The depth of the Estuary Rivers is controlled by the strength of the tidal currents; areas very close to ocean with stronger ...

  5. The effects of increased freshwater inflow on metal enrichment in selected Eastern Cape estuaries, South Africa

    Scientific Electronic Library Online (English)

    KK, Orr; JE, Burgess; PW, Froneman.

    2008-01-01

    Full Text Available The concentrations of select metals (Cd, Co, Cu, Fe, Pb, Ni and Zn) within the water column and sediment of the permanently open Kariega Estuary and temporary open/closed Riet and East Kleinemonde Estuaries were investigated during a dry and a wet season. Enrichment factors (EFs), using Fe as a refe [...] rence element, and baseline linear regression models for metals vs Fe were used to assess the extent of metal enrichment in the sediments. The results of the study indicate that Cd, Co Ni and Pb were enriched above baseline concentrations (1.0

  6. Transfer processes and modelling of plutonium species and gamma emitters in the Scheldt Estuary

    International Nuclear Information System (INIS)

    Radioactive contamination at low levels, of the main European rivers Rhone, Meuse and Scheldt, may be due to two or three specific sources additional to fallout of radionuclides. In the case of the Scheldt, besides the systematic seaward increase of plutonium concentrations in the sediments indicating a marine source of this element, 238Pu distribution in the Western Scheldt estuary altered by additional inputs in the estuary itself. The study of the distribution of Co-60 allowed the identification of the area where the highest contamination by nuclear power plants effluents occurs. (R.P.) 11 figs

  7. Earthquake and human impact on the sedimentology and geochemistry of Ahuriri Estuary, Hawke's Bay

    International Nuclear Information System (INIS)

    Three cores were collected from the intertidal and salt marsh sediments in Ahuriri Estuary, Hawke's Bay, and analysed by sedimentological, chemical and geochronological techniques. Signatures of various events, of both natural and anthropogenic origin, were identified. Evidence for the 1931 Hawke's Bay earthquake, which resulted in an uplift of one to two metres in the Napier area, is given by a change in grainsize distribution in a core from the southern shore of the Lower Estuary. The change to a high energy environment, similar to the present one in the Lower Estuary, has resulted in deposition of sand over fine silt. The data suggest increased sediment accumulation rates following the uplift event, which might be attributed to increased erosion in the upper catchment. There is no evidence of the earthquake at the two other sites sampled, which is probably due to their more sheltered location in the estuary. Post-European settlement impact is mainly restricted to the Lower Estuary, where increased concentrations of Zn, Cr, Pb and Cu may be due to industrial discharges. Evidence of agricultural runoff is given by an increase in Cu concentrations near the Poraiti Hills. The chemical data (Cl and S) suggest a change in the depositional environment in the Upper Estuary due to increased freshwater influx and/or decrease in seawater influence. Dating by 210Pb infers that this occurred prior to 1931, but the origin and timing of the event are still to be determined. Sediment accumulation rates have averaged 2.5 mm/yr for the last 45 years in the Lower Estuary and 3.8 mm/yr for the last 70 years or so in the Upper Estuary. The variation probably reflects the difference in depositional environment, from a high energy environment dominated by tidal and wave action to a low energy environment with additional organic and fine sediment input from stream runoff. The various signatures identified are based on known events but may be used for identifying events in other less well documented sedimentary sequences. (author)

  8. STUDY ON THE EFFECTS OF TIDE ON SEDIMENTATION IN ESTUARIES OF THE NIGER DELTA, NIGERIA

    Directory of Open Access Journals (Sweden)

    Charles Chizom Dike

    2012-12-01

    Full Text Available Niger Delta Estuary Nigeria is influenced by tidal currents due to its proximity to the Atlantic Ocean. Tides in the region are mostly semidiurnal, having two high and low water levels each day, with tidal prism ranging from 0.4 to 1.5m. The effects of tidal current reduces with distance inland and are strongest at the inlets with velocity varying from 2.0 to 5.0m/sec. The depth of the Estuary Rivers is controlled by the strength of the tidal currents; areas very close to ocean with stronger tidal effect are very deep; while shallow rivers predominates the hub of the estuary. Tidal current provides the steady supply of energy that moves sediments in and out of the estuaries from the seashore thus determing river bathymetric shapes through modification of existing morphology by eroding or depositing of sediments along the river course, while further sediment deposition is curtailed at the bottom as the estuary gets shallower due to the increasing stirring by waves. Despite all the sediment coming into the estuaries, many canals in the region have remained as open-water bodies, even after some thousand years. This suggests that, the interaction between the tide and the shape of the canal floor helps to regulate long-term sedimentation. However, the Dredged Canals in the Niger Delta estuaries have suffered high siltation rates because of excessive supply of sediments generated by storm/flood waters from upland and disposal of spoils from dredging activities into the water bodies, which causes some imbalance in the estuarine self-cleaning mechanism. Sediment loads entering the mangrove swamp environment are essentially polycentric; suspended fines enter the system both from the sea and the rivers. A mathematical model was formulated to predict and study the behavior of the sea bed levels, tidal heights and currents, in other to understand how they interact with each other. The model was calibrated using data obtained from local field observations and measurements. The model results compares favorably with the field results, with average correlation coefficient of 0.9 (see figures 2-13.The result showed that Niger Delta estuaries erode, accrete, or remain stable, depending on the rate at which sediment is supplied or removed from them by flood waters and tidal currents.

  9. Design of a basinwide monitoring program for the Tampa Bay estuary. Final technical pub

    International Nuclear Information System (INIS)

    The Tampa Bay National Estuary Program (TBNEP) is developing a Comprehensive Conservation and Management Plan (CCMP) to recommend management actions for protecting the Tampa Bay estuary. The purpose of the document is to facilitate development of the monitoring program by assisting the TBNEP to define the objectives of a monitoring program for Tampa Bay identifying indicators and a sampling design that are appropriate to those objectives, and identifying how existing Tampa Bay monitoring programs can be incorporated and modified (if necessary) to meet the monitoring objectives

  10. Population ecology of the blue crab Callinectes danae (Crustacea: Portunidae) in a Brazilian tropical estuary

    OpenAIRE

    Marina S. L. C. Araújo; Aline V. Barreto; Aurinete O. Negromonte; Ralf Schwamborn

    2012-01-01

    This paper aims at describing the population ecology of the swimming crab Callinectes danae Smith, 1869 in one of the most productive estuaries of Brazil, the Santa Cruz Channel. These crabs were monthly collected from January to December/2009 at four stations along the channel, two in the upper and two in the lower estuary. A total of 2373 specimens of C. danae were collected during the study. Males had a larger average carapace width than non-ovigerous females (60.0 ± 15.6 mm and 52.9 ± 12....

  11. The effects of organic inputs to estuaries on overwintering bird populations and communities

    International Nuclear Information System (INIS)

    This study investigates the relationship between changes in organic inputs to river estuaries and other coastal intertidal areas, and changes in the populations of waterfowl in these habitats. This is done in the context of tidal barrage construction, where barrage construction and operation may coincide with the cleaning of estuarine water. A thorough review of the literature is undertaken to determine the current status of knowledge of bird/organic-enrichment interactions. The use of multivariate statistics for identifying gradients in similarity between bird communities (specifically waders) of different estuaries, irrespective of geographic locations is investigated. (UK)

  12. Geochemical analysis of Minho Estuary sedimentary record and its contribution to palaeoenvironmental evolution

    International Nuclear Information System (INIS)

    Two sediment cores (?30 m long) were retrieved at the mouth of the Minho Estuary to assess its palaeoenvironmental evolution for the last millennia. Samples were characterized by Energy-Dispersive X-Ray Fluorescence Spectrometry and Instrumental Neutron Activation Analysis, complemented by sedimentological analyses. Provenance of major and trace element contents (lithogenic or biogenic, continental or marine) is assessed. The influence of grain size effect on total element concentration is discussed. Most of the samples present a negative Eu anomaly. Sedimentological and geochemical parameters allow differentiating four geological units - fluvial, marine, estuarine and sand barrier - which reflects the temporal evolution of the Minho Estuary. (author)

  13. Studies on the associates and parasites of zooplankton from southwest and southeast coasts of India

    Digital Repository Service at National Institute of Oceanography (India)

    Santhakumari, V.

    Associates and parasites of zooplankton from southwest and southeast coasts of India were studied. Among the epizoic forms two species of ciliates infesting copepods were new records from Indian waters. Eight species of suctorians were found epizoic...

  14. Nutrient environment of red tide- infested waters off south-west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Joseph, T.; Shaiju, P.; Laluraj, C.M.; Balachandran, K.K.; Nair, M.; George, R.; Nair, K.K.C.; Sahayak, S.; Prabhakaran, M.P.

    The bloom-infested waters along the southwest coast of India were assessed to bring about the probable cause related to the excessive algal production. Low nitrate and silicate concentrations were concomitant with slightly higher levels of phosphate...

  15. Shallow-Water Benthic Habitats of Southwest Puerto Rico: GeoEye Image po_0072610_PS

    Data.gov (United States)

    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...

  16. Southwest Research Institute assistance to NASA in biomedical areas of the technology utilization program

    Science.gov (United States)

    Culclasure, D. F.; Sigmon, J. L.; Carter, J. M.

    1973-01-01

    The activities are reported of the NASA Biomedical Applications Team at Southwest Research Institute between 25 August, 1972 and 15 November, 1973. The program background and methodology are discussed along with the technology applications, and biomedical community impacts.

  17. Shallow-Water Benthic Habitats of Southwest Puerto Rico: GeoEye Image po_502736_PS

    Data.gov (United States)

    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...

  18. Shallow-Water Benthic Habitats of Southwest Puerto Rico: GeoEye Image po_1700252_PS

    Data.gov (United States)

    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...

  19. Observational evidence of upwelling off the southwest coast of India during June-July 2006

    Digital Repository Service at National Institute of Oceanography (India)

    Lekshmi, S.; Smitha, B.R.; Revichandran, C.

    Considerable latitudinal variability exists in the forcing mechanisms and intensity of coastal upwelling along the southwest coast of India. Present work is based on the insitu observations conducted onboard FORV Sagar Sampada for 12 days along two...

  20. National Status and Trends: Bioeffects Program - Southwest Puerto Rico Chemical Contaminant Assessment Summary

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The purpose of the project was to characterize the extent and magnitude of chemical contamination in southwest Puerto Rico, as part of a larger effort to link coral...

  1. Resource Assessment for Microalgal/Emergent Aquatic Biomass Systems in the Arid Southwest: Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Vigon, B. W.; Arthur, M. F.; Taft, L. G.; Wagner, C. K.; Lipinsky, E. S.; Litchfield, J. H.; McCandlish, C. D.; Clark, R.

    1982-12-23

    This research project has been designed to facilitate the eventual selection of biomass production systems using aquatic species (microalgal and emergent aquatic plant species (MEAP) which effectively exploit the potentially available resources of the Southwest.

  2. Sabine National Wildlife Refuge: Southwest Louisiana National Wildlife Refuge Complex: Comprehensive Conservation Plan

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Comprehensive Conservation Plan CCP was written to guide management on Sabine NWR and Southwest Louisiana NWR Complex for the next 15 years. This plan outlines...

  3. Shallow-Water Benthic Habitats of Southwest Puerto Rico: Accuracy Assessment Site Locations

    Data.gov (United States)

    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...

  4. Shallow-Water Benthic Habitats of Southwest Puerto Rico: Ground Validation Site Locations

    Data.gov (United States)

    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. Hydrography and circulation in the northwestern Bay of Bengal during the retreat of southwest monsoon

    Digital Repository Service at National Institute of Oceanography (India)

    Murty, V.S.N.; Sarma, Y.V.B.; Babu, M.T.; Rao, D.P.

    The distribution of temperature and salinity in the upper 500 m of the northwestern Bay of Bengal, adjoining the East Coast of India, during the retreat of southwest monsoon (September) of 1983 is presented. This study reveals coastal upwelling...

  6. Water characteristics, mixing and circulation in the Bay of Bengal during southwest monsoon

    Digital Repository Service at National Institute of Oceanography (India)

    Murty, V.S.N.; Sarma, Y.V.B.; Rao, D.P.; Murty, C.S.

    Influence of the freshwater influx, the wind forcing and the Indian Ocean monsoon drift current on the property distributions and the circulation in the Bay of Bengal during southwest monsoon has been quantified. At the head of the Bay, waters...

  7. Potential vorticity field in the Bay of Bengal during southwest monsoon

    Digital Repository Service at National Institute of Oceanography (India)

    Murty, V.S.N.; Rao, D.P.

    The distribution of potential vorticity along potential density surfaces in the upper 500 m indicates the presence of a wind driven anticyclonic gyre between 10 degrees N and 14 degrees N in the eastern Bay during southwest monsoon. The vertical...

  8. 2007 Southwest Florida Water Management District (SWFWMD) LiDAR: Hernando County

    Data.gov (United States)

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

  9. Precipitation Frequency for Semiarid Southwest, USA - NOAA Atlas 14 Volume 1

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This GIS grid atlas contains precipitation frequency estimates for the Semiarid Southwest based on precipitation data collected between 1893-2000. This atlas is an...

  10. Shallow-Water Benthic Habitats of Southwest Puerto Rico: GeoEye Image po_483895_PS

    Data.gov (United States)

    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...

  11. Zooplankton of the southwest coast of India: abundance, composition, temporal and spatial variability in 1987

    Digital Repository Service at National Institute of Oceanography (India)

    Madhupratap, M.; Haridas, P.; Ramaiah, Neelam; Achuthankutty, C.T.

    During early southwest and northeast monsoon periods of 1967, zooplankton standing stocks and abundances were high all along the west coast of India. Swarms of zooplankton were common in the shelf areas resulting in a low diversity-high biomass...

  12. Hydrographic characterization of southeast Arabian Sea during the wane of southwest monsoon and spring intermonsoon

    Digital Repository Service at National Institute of Oceanography (India)

    VimalKumar, K.G.; DineshKumar, P.K.; Smitha, B.R.; Rahman, H.H.; Jacob, J.; Muraleedharan, K.R.; Sanjeevan, V.N.; Achuthankutty, C.T.

    Seasonal variation of the hydrography along the southeast Arabian Sea is described using data collected onboard FORV Sagar Sampada in September-October 2003 (later phase of Southwest monsoon, SWM) and March-April 2004 (Spring inter monsoon, SIM...

  13. Shallow-Water Benthic Habitats of Southwest Puerto Rico: GeoEye Image po_0100092_PS

    Data.gov (United States)

    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...

  14. Shallow-Water Benthic Habitats of Southwest Puerto Rico: GeoEye Image po_0900172_PS

    Data.gov (United States)

    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...

  15. Bedforms and sediment distribution in the Minho estuary (Northern Portugal)

    Science.gov (United States)

    Duarte, Henrique

    2010-05-01

    Here are presented preliminary results of the MINHO09 cruise, carried out within the scope of the paleoclimatic research task of the MINHO project (PROYECTO 0234_NATURA_MIÑO_MINHO). Bed features and sediment distribution were mapped in the Minho estuary (Northern Portugal) using a dual frequency sidescan sonar mosaic (EdgeTech 4200-MP), and bottom sediment texture data from 71 sites sampled with a winch operated sediment grab (Van Veen type). The survey was done within 5 days, in low flow energy conditions of summer dry weather and neap tides, close to optimal conditions for correlating the acoustic imagery with the bottom sediment data. A DGPS (Omnistar 8200HP) was used to determine the horizontal position of the acoustic imagery and the sediment sample sites with sub-meter accuracy. Uncorrected water depths were determined with a depth echo-sounder (Odom HYDROTRAC echo sounder), and the water depths referred to the local datum was later determined using data from a tidal gauge (Valeport model 740) deployed specifically for this survey. Overall the sampled sediments were mostly poorly calibrated, with grain sizes ranging from gravel to mud coexisting in the same sample, probably reflecting the great seasonal contrast in flow conditions in the Minho River. The predominantly muddy sediments were observed along the river margins (frequently charged with gas) and, locally, along relatively deeper portions of the channel bed. The bedforms observed in the sidescan sonar data are dominated by 2D and 3D dunes and ripples. There are several locations were the bedforms suddenly change from larger dunes (wave lengths greater than 5m) to smaller ripples (wave lengths smaller than 1m). These changes may be related to the occurrence of supercritical flow conditions (Froude number > 1): hydraulic jumps in places were there is a sudden change in depth without any change in channel width, or chutes and pools in places were there is a sudden change in channel width; future work is planed to answer this question by doing a detailed comparison of the bedforms, sediment texture and bathymetric data (data that was not yet available at the time of writing of this abstract). Fan shaped echoes and associated sediment landslide scars are frequently observed near steeper channel margins and at the foot of ship docking ramps, evidence of sediment input directly from the river margins. The muddy river margins frequently exhibited a stair case pattern of low reflectivity in the horizontal segments, and strong linear echoes in the steeper portions of the "stair case" margin. This same pattern was also observed in the muddy margins of a regularly dredged channel that crosses a large area of sand bars in the middle of the estuary. The preliminary interpretation of this pattern is that it is caused by the deposition and slumping of muddy sediments along the margins in the low energy conditions that were predominant during the spring and summer season prior to the survey. Sea grass is clearly recognizable in the form of densely packed irregular lines of strong echoes, and is abundant upriver towards Tuy, probably outside the tidal influence. Some of the acoustic "speckle" found in the sonar imagery may be evidence of the bivalve Fluminea corbiola present in most samples. This bivalve is an invasive species in the area, originally from Asia.

  16. Potential for increased mercury accumulation in the estuary food web

    Directory of Open Access Journals (Sweden)

    Samuel N. Luoma

    2003-10-01

    Full Text Available Present concentrations of mercury in large portions of San Francisco Bay (Bay, the Sacramento-San Joaquin Delta (Delta, and the Sacramento and San Joaquin rivers are high enough to warrant concern for the health of humans and wildlife. Large scale tidal wetland restoration is currently under consideration as a means of increasing populations of fish species of concern. Tidal wetland restoration activities may lead to increased concentrations of mercury in the estuarine food web and exacerbate the existing mercury problem. This paper evaluates our present ability to predict the local and regional effects of restoration actions on mercury accumulation in aquatic food webs. A sport fish consumption advisory is in place for the Bay, and an advisory is under consideration for the Delta and lower Sacramento and San Joaquin rivers. Mercury concentrations in eggs of several water bird species from the Bay have exceeded the lowest observed effect level. A variety of mercury sources, largely related to historic mercury and gold mining, is present in the watershed and has created a spatially heterogeneous distribution of mercury in the Bay-Delta Estuary. Mercury exists in the environment in a variety of forms and has a complex biogeochemical cycle. The most hazardous form, methylmercury, is produced at a relatively high rate in wetlands and newly flooded aquatic habitats. It is likely that distinct spatial variation on multiple spatial scales exists in net methylmercury production in Bay-Delta tidal wetlands, including variation within each tidal wetland, among tidal wetlands in the same region, and among tidal wetlands in different regions. Understanding this spatial variation and its underlying causes will allow environmental managers to minimize the negative effects of mercury bioaccumulation as a result of restoration activities. Actions needed to reduce the uncertainty associated with this issue include a long term, multifaceted research effort, long term monitoring on local and regional scales, and careful evaluation of individual restoration projects with regard to potential increase of food web mercury.

  17. Status of the belugas of the St Lawrence estuary, Canada

    Directory of Open Access Journals (Sweden)

    Michael CS Kingsley

    2014-01-01

    Full Text Available A population of belugas (Delphinapterus leucas inhabiting the estuary of the St Lawrence river in Quebec, Canada, was depleted by unregulated hunting, not closed until 1979. Surveys in 1977 showed only a few hundred in the population. Surveys since then have produced increasing estimates of population indices. An estimate of the population, fully corrected for diving animals, was 1,238 (SE 119 in September 1997. The population was estimated to have increased from 1988 through 1997 by 31.4 belugas/yr (SE 13.1. Observations of population age structure, as well as data on age at death obtained from beach-cast carcasses, do not indicate serious problems at the population level, although there are indications that mortality of the oldest animals may be elevated. Few animals appear to live much over 30 years. From examination of beach-cast carcasses, it appears that most deaths are due to old age and disease; hunting is illegal, ship strikes and entrapments in fishing gear are rare, ice entrapments and predation are unknown. Among beach-cast carcasses recovered and necropsied, about 23% of the adults have malignant cancers, while most of the juveniles have pneumonia; other pathological conditions are diverse. No factors are known to be limiting numbers of this population. Habitat quality factors, including persistent contaminants, boat traffic and harassment, may affect the population’s rate of increase, but these effects have not been quantitatively evaluated. Comprehensive legislation exists with powers to protect the population and the environment of which it is a component, but application and enforcement of the laws is not without problems.

  18. HIGHLIGHTS IN MATCHING LABOUR WITH LABOUR MARKET NEEDS IN THE REGION OF SOUTH-WEST OLTENIA

    OpenAIRE

    Victor TITA

    2012-01-01

    This paper emphasizes the importance of several items in linking labour with labour market needs in the region of South-West Oltenia. By reference to the proposed research objectives, research instrument was a sociological survey, representing two sets of questions for two distinct target groups: unemployed and representatives of companies in the region. These instruments allowed an assessment of labour market in South-West Oltenia region, the present study highlighting some aspects of skills...

  19. Exploring the Etiologic Factors and Dynamics of Prescription Drug Abuse in Southwest Virginia

    OpenAIRE

    Redican, Kerry J; Lydia I. Marek; Donna JP Brock; MCCANCE-KATZ, ELINORE F.

    2012-01-01

    Background: Prescription drug abuse in Southwest Virginia is a serious problem affecting indi-viduals, families, and communities. The aim of this study was to characterize and understand the extent of the prescription drug abuse problem in Southwest, Virginia as well as the dynamics that surround that abuse. More specifically, the study focused on learning the extent of the problem along with which prescription drugs are typically used prior to entering treatment, reasons for prescription dru...

  20. Investigating turkey (Meleagris gallopavo) domestication in the Southwest United States through ancient DNA analysis

    OpenAIRE

    Speller, Camilla Filomena

    2009-01-01

    As one of the New World’s few animal domesticates, the turkey (Meleagris gallopavo) represented an important resource for the Ancestral Puebloans of the Southwest United States. Despite the rich database of Southwest archaeology, several questions concerning the domestication and use of turkeys remain unanswered, including the geographic origin of turkey domestication, the pre-contact flock management and breeding practices, and the changing roles of wild and domestic turkeys through time. In...

  1. Mesoscale modeling study of the oceanographic conditions off the southwest coast of India

    OpenAIRE

    Haugen, Vibeke E.; Johannessen, Ola M.; Evensen, Geir

    2002-01-01

    A high resolution model, using the Miami Isopycnic Coordinate Ocean Model (MICOM), has been implemented for the first time to study the seasonal circulation and coastal upwelling off the southwest Indian coast during 1974. This model is part of a model and data assimilation system capable of describing the ocean circulation and variability in the Indian Ocean and its predictability in response to the monsoon system. Along the southwest coast of India the dominant coastal current i...

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

    OpenAIRE

    Fei HUANG

    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 ethnographic fieldwork I demonstrate that despite the Qing Empire’s remaking of the indigenous landscape in the eighteenth century, indigenous concepts of landscape and space have survived to the present in ...

  3. Measurements and simulation of speciated PM2.5 in south-west Europe

    OpenAIRE

    Milford, C.; Castell, Nuria; Marrero, C.; Rodríguez González, Sergio; Sánchez de la Campa Verdona, Ana María; Fernández Camacho, Rocío; Rosa Díaz, Jesús de la; Stein, Ariel

    2013-01-01

    Chemically speciated concentrations of PM2.5 (sulphate, ammonium, nitrate, elemental and organic carbon) were simulated in south-west Europe using the three-dimensional air quality model CAMx driven by the MM5 meteorological model. The inner domain covered the south-west region of Spain with a high spatial (2 km 2 km) and temporal resolution (1 h). The simulation results were evaluated against experimental data obtained in four intensive field campaigns performed in 2008 and 200...

  4. DETERMINANTS OF INCOME DIVERSIFICATION AMONGST RURAL FARM HOUSEHOLDS IN SOUTHWEST NIGERIA

    OpenAIRE

    Idowu, Adewunmi. O.; Aihonsu, John O.Y; Olubanjo, Olugbenga O.; Shittu, Adebayo M.

    2011-01-01

    This study aims to analyze the determinants of household income diversification and the share of income sources to total household income among the rural farm households in southwest Nigeria. The study drew a sample of 411 rural farm households through a multi-stage sampling technique from three states in southwest Nigeria and the data obtained were analyzed using the Herfindal index and Tobit regressions. Results indicate that the level of income diversification among rural farm households...

  5. Bird migration patterns in the arid southwest-Final report

    Science.gov (United States)

    Ruth, Janet M.; Felix, Rodney K.; Dieh, Robert H.

    2010-01-01

    To ensure full life-cycle conservation, we need to understand migrant behavior en route and how migrating species use stopover and migration aerohabitats. In the Southwest, birds traverse arid and mountainous landscapes in migration. Migrants are known to use riparian stopover habitats; we know less about how migrant density varies across the Southwest seasonally and annually, and how migrants use other habitat types during migratory stopover. Furthermore, we lack information about migrant flight altitudes, speeds, and directions of travel, and how these patterns vary seasonally and annually across the Southwest. Using weather surveillance radar data, we identified targets likely dominated by nocturnally migrating birds and determined their flight altitudes, speeds, directions over ground, and variations in abundance. Migrating or foraging bats likely are present across the region in some of these data, particularly in central Texas. We found that migrants flew at significantly lower altitudes and significantly higher speeds in spring than in fall. In all seasons migrants maintained seasonally appropriate directions of movement. We detected significant differences in vertical structure of migrant densities that varied both geographically within seasons and seasonally within sites. We also found that in fall there was a greater and more variable passage of migrants through the central part of the borderlands (New Mexico and west Texas); in spring there was some suggestion of greater and more variable passage of migrants in the eastern borderlands (central and south Texas). Such patterns are consistent with the existence of at least two migration systems through western North America and the use of different migration routes in spring and fall for at least some species. Using radar data and satellite land cover data, we determined the habitats with which migrants are associated during migration stopover. There were significant differences in bird densities among habitat types at all sites in at least one season. Upland forest habitat in parts of Arizona and New Mexico supported high migrant densities, especially in fall. Developed habitats in areas with little upland forest habitat also supported high migrant densities. Scrub/shrub and grassland habitats supported low to intermediate migrant densities, but because these habitat types dominate the region, they may support large numbers of migratory birds. This may be especially true for species that do not use forested habitats during migration. Target identity remains a challenge for radar-based studies. Presence of bats in the data complicates interpretation of some observations, particularly from central Texas. Based on our results it is simplistic to: (1) consider the arid west as a largely inhospitable landscape in which there are only relatively small oases of habitat that provide the resources needed by all migrants; (2) think of western riparian and upland forest habitat as supporting the majority of migrants in all cases; or (3) consider a particular habitat type unimportant migrant stopover habitat based solely on migrant densities.

  6. The link between water quality and tidal marshes in a highly impacted estuary.

    Science.gov (United States)

    Meire, Patrick; Maris, Tom; van Damme, Stefan; Jacobs, Sander; Cox, Tom; Struyf, Eric

    2010-05-01

    The Schelde estuary is one of the most heavily impacted estuaries in Europe. During several decades, untreated waste water from large cities (e.g. Brussels, Antwerp, Valenciennes, Lille) and industries was discharged in the river. As a result, the Schelde estuary has the reputation of being one of the most polluted estuaries in Europe. For a long time (approx. 1950 - 1995) all forms of higher life (macro-invertebrates and fish) were absent in the fresh and brackish parts of the estuary. Due to European legislation, a large part of the sewage water is now treated resulting in a significant recovery of water quality in the estuary. However, next to water quality, the estuary also suffered serious habitat losses during the last decades, mostly due to economic development and changing hydrological conditions causing more erosion. Over the last fifteen years, the management of the estuary has changed fundamentally. It is now more and more focused on the restoration of ecosystem services. In this presentation we will document the changes in water quality over the last 50 years and summarize recent work on the role of tidal marshes on water quality within the freshwater part of the Schelde estuary. Our results stress the important of taking into account ecosystem services and habitat restoration for long-term estuarine management. .After decades of high inorganic nutrient concentrations and recurring anoxia and hypoxia, we observed a paradoxical increase in chlorophyll-a concentrations with decreasing nutrient inputs, indicating a regime shift. Our results indicate that the recovery of a hypereutrophied systems towards a classical eutrophied state, needs the reduction of waste loads below certain thresholds. Paradoxically, phytoplankton production was inhibited by high ammonia or low oxygen concentrations. The system state change is accompanied by large fluctuations in oxygen concentrations. The improved water quality resulted in a remarkable recovery of different groups of higher organisms, especially fish populations. It is clear that the improved water quality is to a large part due to improved waste water treatment. However detailed studies of the exchange between tidal marshes and the estuary clearly proved also the importance of these habitats for water quality. A whole ecosystem labeling experiment gave evidence on the sink function of these marshes for nitrogen. Detailed mass balance studies show also the importance of mashes in the silica cycle. Amorphous biogenic silica is imported into marshes were it accumulates in the soil, while dissolved silica is exported again to the pelagic. At times when the concentrations of dissolved silica in the estuary are limiting (during plankton blooms), the export of DSi from the marshes is highest. These results clearly indicate the crucial role tidal marshes play in the estuarine biogeochemical cycles and in their resilience against imbalanced nutrient inputs. Based on these insights new tidal marshes have been developed along the Schelde, their design being so that the delivery of ecosystems services (eg impact on water quality) is maximal.

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

    Science.gov (United States)

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

    2012-12-01

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

  8. Role of intertidal wetlands for tidal and storm tide attenuation along a confined estuary: a model study

    Science.gov (United States)

    Smolders, S.; Plancke, Y.; Ides, S.; Meire, P.; Temmerman, S.

    2015-07-01

    Coastal lowlands and estuaries are subjected to increasing flood risks during storm surges due to global and regional changes. Tidal wetlands are increasingly valued as effective natural buffers for storm surges by dissipating wave energy and providing flood water storage. While previous studies focused on flood wave attenuation within and behind wetlands, this study focuses on the effects of estuarine wetland properties on the attenuation of a storm tide that propagates along the length of an estuary. Wetland properties including elevation, surface area, and location within the estuary were investigated using a numerical model of the Scheldt estuary (Belgium, SW Netherlands). For a spring tide lower wetland elevations result in more attenuation of high water levels along the estuary, while for a higher storm tide higher elevations provide more attenuation compared to lower wetland elevations. For spring and storm tide a larger wetland surface area results in a better attenuation along the estuary up to a threshold wetland size for which larger wetlands do not further contribute to more attenuation. Finally a wetland of the same size and elevation, but located more upstream in the estuary, can store a larger proportion of the local flood volume and therefore has a larger attenuating effect on upstream high water levels. With this paper we aim to contribute towards a better understanding and wider implementation of ecosystem-based adaptation to increasing estuarine flood risks associated with storms.

  9. Wind-driven lateral circulation in a stratified estuary and its effects on the along-channel flow

    Science.gov (United States)

    Li, Yun; Li, Ming

    2012-09-01

    In the stratified rotating estuary of Chesapeake Bay, the Ekman transport drives a counterclockwise lateral circulation under down-estuary winds and a clockwise lateral circulation under up-estuary winds (looking into estuary). The clockwise circulation is about twice as strong as the counterclockwise circulation. Analysis of the streamwise vorticity equation reveals a balance among three terms: titling of the planetary vorticity by vertical shear in the along-channel current, baroclinic forcing due to sloping isopycnals at cross-channel sections, and turbulent diffusion. The baroclinic forcing is highly asymmetric between the down- and up-estuary winds. While the counter-clockwise lateral circulation tilts isopycnals vertically and creates lateral barolinic pressure gradient to oppose the Ekman transport under the down-estuary wind, the clockwise circulation initially flattens the isopycnals and the baroclinic forcing reinforces the Ekman transport under the up-estuary wind. The Coriolis acceleration associated with the lateral flows is of the first-order importance in the along-channel momentum balance. It has a sign opposite to the stress divergence in the surface layer and the pressure gradient in the bottom layer, thereby reducing the shear in the along-channel current. Compared with the non-rotating system, the shear reduction is about 30-40%. Two summary diagrams are constructed to show how the averaged streamwise vorticity and along-channel current shear vary with the Wedderburn (W) and Kelvin (Ke) numbers.

  10. Influences of Environmental Factors on Fish Assemblage in the Tropical Estuary of South West Coast of India, A Case Study of Kodungallur-Azhikode Estuary

    Directory of Open Access Journals (Sweden)

    O.K. Sreedevi

    2013-01-01

    Full Text Available A proper monitoring of aquatic environment is crucial to appropriate management of the fisheries that rely on harvests from the environment and attempts of present study have been made to demonstrate links with environmental variability and fish abundance in the Kodungallur-Azhikode estuary (KAE. Annual average fish production in the estuary was declined considerably to 908.6 tons during 2009-2010, where 2747 tons was reported. Sixty three species of fin fishes, six species of penaeid shrimps, one species of Palaemonid prawns, two species of crabs, four species of bivalves and two species of edible oysters were observed in this study. Present study revealed that, Salinity is consistently the most important parameter explaining variation in assemblage composition and abundance of KAE; the availability of fish for recruitment into an estuary depends primarily upon the distributional range of euryhaline marine and estuarine species. The direct gradient analysis, first CCA axis, which explained most of the variation (45% in the species data, was related to salinity, transparency and pH, and first two CCA axes together explained 72% of the cumulative percent variance of species-environment relationship. The importance of monitoring the estuarine condition in relation to fish assemblage was discussed, with significance on the potential use of estuarine fish assemblages and their monitoring and surveillance in management programs.

  11. Turtle riders: remoras on marine turtles in Southwest Atlantic

    Directory of Open Access Journals (Sweden)

    Ivan Sazima

    2006-03-01

    Full Text Available An overview is presented for a poorly documented relationship between reef vertebrates in Southwest Atlantic: remoras (Echeneidae associated with marine turtles. Two remora species (Echeneis naucrates and Remora remora and four turtle species (Caretta caretta, Chelonia mydas, Eretmochelys imbricata, and Dermochelys coriacea are here recorded in symbiotic associations in the SW Atlantic. Echeneis naucrates was recorded both on the coast and on oceanic islands, whereas R. remora was recorded only at oceanic islands and in the open sea. The remora-turtle association is usually regarded as an instance of phoresis (hitchhiking, albeit feeding by the fish is also involved in this symbiosis type. This association seems to be rare in SW Atlantic.Uma visão geé apresentada sobre uma relação pouco documentada entre vertebrados recifais no Atlântico Sul Ocidental: rêmoras (Echeneidae associadas a tartarugas marinhas. Duas espécies de rêmora ou pegador (Echeneis naucrates e Remora remora e quatro de tartarugas (Caretta caretta, Chelonia mydas, Eretmochelys imbricata e Dermochelys coriacea são aqui registradas em associações simbiônticas para o Atlântico Sul Ocidental. Echeneis naucrates foi registrada tanto na costa como em ilhas oceânicas, ao passo que R. remora foi registrada somente em ilhas oceânicas e região pelágica. A associação entre rêmoras e tartarugas é habitualmente considerada como forese, embora forrageamento, por parte das rêmoras, também esteja envolvido neste tipo de simbiose. Esta associação parece ser rara no Atlântico Sul Ocidental.

  12. NCLB: Local implementation and impact in southwest Washington state.

    Directory of Open Access Journals (Sweden)

    Linda Mabry

    2006-09-01

    Full Text Available The research reported here is from the first two years of an ongoing and largely qualitative study to examine the impact of the No Child Left Behind federal education policy on educational practice and climate in elementary schools in two districts in southwest Washington. Based on systematic drop-in observations in classrooms and interviews with teachers and school and district administrators, data indicated that the policy had partially yielded the intended standards-based reforms but at considerable local cost. While most participating administrators described efforts to use NCLB to leverage needed change, most teachers described struggles to sustain best practice and to avoid some negative consequences to their students and schools. Administrators anticipated that resistant teachers would be nudged from the profession, and the greatest attrition among participating teachers was from the fourth-grade level at which the state’s standards-based test was administered. Fourth-grade teachers particularly expressed concern about test-related stress and test-driven curricula interfering with children’s individual needs and with their own ability to provide developmentally appropriate instruction adapted for their particular students. The validity and utility of test results was a local issue.

  13. Epidemiological evaluation of onchocerciasis along Ogun River System, southwest Nigeria

    Directory of Open Access Journals (Sweden)

    S.O. Sam-Wobo , M.A. Adeleke , O.A. Jayeola , A.O. Adeyi , A.S. Oluwole , M. Ikenga , A. Lawniye , J. Gazama , A. Kagni , T.O. Kosoko , O. Agbeyangi , S. Bankole , L. Toé , C.F. Mafiana & L. Yameogo

    2012-06-01

    Full Text Available Background & objective: Epidemiological studies were carried out to assess the prevalence and communitymicrofilarial load (CMFL of onchocerciasis after repeated annual treatment with ivermectin along Ogun riverSystem, southwest Nigeria.Method: Skin snips were taken from consented participants in 11 selected communities along the River system.The microfilarial load of the community was estimated.Results: The prevalence and CMFL varied significantly in the communities (p <0.05. The prevalence ofonchocerciasis ranged from 19.1 to 45.6%, while the CMFL ranged from 0.11 to 1.03 microfilariae per skinsnip. The CMFL recorded was <5 microfilariae per skin snip, i.e. recognized by WHO as threshold value incertifying the communities to be free of onchocerciasis as public health problem, thus, signifying the possibilityof onchocerciasis elimination in the study area.Conclusion: Efforts should therefore be intensified to achieve improved ivermectin coverage and compliance inannual ivermectin treatment in order to completely eliminate onchocerciasis as a public health problem in thestudied communities.

  14. Chronic oil pollution harms Magellanic penguins in the Southwest Atlantic.

    Science.gov (United States)

    García-Borboroglu, Pablo; Boersma, P Dee; Ruoppolo, Valeria; Reyes, Laura; Rebstock, Ginger A; Griot, Karen; Rodrigues Heredia, Sergio; Adornes, Andrea Corrado; da Silva, Rodolfo Pinho

    2006-02-01

    Petroleum pollution is a problem for seabirds along the Southwest Atlantic coast. Twenty-five groups from Salvador, Brazil (12 degrees 58'S) to San Antonio Oeste, Argentina (40 degrees 43'S) survey or rehabilitate sick or oiled seabirds. Four groups, one each in Brazil and Uruguay, and two in Argentina, kept counts of birds found alive and in need of rehabilitation. An average of 63.7% of the seabirds found were Magellanic penguins (Spheniscus magellanicus), with 3869 reported since 1987. Mainly adult penguins were found in Argentina (1605 of 2102 penguins of known age class) and Uruguay (158 of 197). Juveniles were most common in Brazil (234 of 325). Oil fouling was the most frequent cause of injury or sickness. The number of oiled penguins reported in their wintering range has greatly increased since the early 1990s and is strongly correlated with petroleum exports from Argentina. Our results show that chronic petroleum pollution is a problem for wildlife from Southern Brazil through Northern Argentina, and regulations and enforcement are failing to protect living resources. PMID:16364372

  15. Turtle riders: remoras on marine turtles in Southwest Atlantic

    Scientific Electronic Library Online (English)

    Ivan, Sazima; Alice, Grossman.

    2006-03-01

    Full Text Available Uma visão geé apresentada sobre uma relação pouco documentada entre vertebrados recifais no Atlântico Sul Ocidental: rêmoras (Echeneidae) associadas a tartarugas marinhas. Duas espécies de rêmora ou pegador (Echeneis naucrates e Remora remora) e quatro de tartarugas (Caretta caretta, Chelonia mydas, [...] Eretmochelys imbricata e Dermochelys coriacea) são aqui registradas em associações simbiônticas para o Atlântico Sul Ocidental. Echeneis naucrates foi registrada tanto na costa como em ilhas oceânicas, ao passo que R. remora foi registrada somente em ilhas oceânicas e região pelágica. A associação entre rêmoras e tartarugas é habitualmente considerada como forese, embora forrageamento, por parte das rêmoras, também esteja envolvido neste tipo de simbiose. Esta associação parece ser rara no Atlântico Sul Ocidental. Abstract in english An overview is presented for a poorly documented relationship between reef vertebrates in Southwest Atlantic: remoras (Echeneidae) associated with marine turtles. Two remora species (Echeneis naucrates and Remora remora) and four turtle species (Caretta caretta, Chelonia mydas, Eretmochelys imbricat [...] a, and Dermochelys coriacea) are here recorded in symbiotic associations in the SW Atlantic. Echeneis naucrates was recorded both on the coast and on oceanic islands, whereas R. remora was recorded only at oceanic islands and in the open sea. The remora-turtle association is usually regarded as an instance of phoresis (hitchhiking), albeit feeding by the fish is also involved in this symbiosis type. This association seems to be rare in SW Atlantic.

  16. Perinatal Outcomes and Unconventional Natural Gas Operations in Southwest Pennsylvania

    Science.gov (United States)

    Stacy, Shaina L.; Brink, LuAnn L.; Larkin, Jacob C.; Sadovsky, Yoel; Goldstein, Bernard D.; Pitt, Bruce R.; Talbott, Evelyn O.

    2015-01-01

    Unconventional gas drilling (UGD) has enabled extraordinarily rapid growth in the extraction of natural gas. Despite frequently expressed public concern, human health studies have not kept pace. We investigated the association of proximity to UGD in the Marcellus Shale formation and perinatal outcomes in a retrospective cohort study of 15,451 live births in Southwest Pennsylvania from 2007–2010. Mothers were categorized into exposure quartiles based on inverse distance weighted (IDW) well count; least exposed mothers (first quartile) had an IDW well count less than 0.87 wells per mile, while the most exposed (fourth quartile) had 6.00 wells or greater per mile. Multivariate linear (birth weight) or logistical (small for gestational age (SGA) and prematurity) regression analyses, accounting for differences in maternal and child risk factors, were performed. There was no significant association of proximity and density of UGD with prematurity. Comparison of the most to least exposed, however, revealed lower birth weight (3323 ± 558 vs 3344 ± 544 g) and a higher incidence of SGA (6.5 vs 4.8%, respectively; odds ratio: 1.34; 95% confidence interval: 1.10–1.63). While the clinical significance of the differences in birth weight among the exposure groups is unclear, the present findings further emphasize the need for larger studies, in regio-specific fashion, with more precise characterization of exposure over an extended period of time to evaluate the potential public health significance of UGD. PMID:26039051

  17. Many southwest hosptials will receive decreased CMS reimbursement

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    Robbins RA

    2013-11-01

    Full Text Available No abstract available. Article truncated at 150 words. More hospitals are receiving penalties than bonuses in the second year of the Centers for Medicare and Medicaid Services’ (CMS quality incentive program, and the average penalty is steeper than last year according to a report from Jordan Rau in Kaiser Health News (1. Southwest hospitals reflect that trend with New Mexico and Arizona exceeding the US average both in percentage of hospitals receiving penalties and the average size of the penalty (Table 1. Colorado approximated the national averages (Table 1. Most hospitals are gaining or losing <0.2% but in some instances the penalties are substantial. Gallup Indian Medical Center in New Mexico, a federal government hospital on the border of the Navajo Reservation, will be paid 1.14 percent less for each patient and New Mexico’s average of a -0.31% decline in reimbursement are the largest changes nationally. “This program is driving what we want in health care,” said Dr. …

  18. Unlocking the Secrets of the Geodynamo: the Southwest Pacific Key

    Science.gov (United States)

    Turner, G. M.; Greve, A.; Kinger, R.; de Gelder, G.; Fitzsimons, S.; Howarth, J. D.; Hill, M. J.; Nilsson, A.; Sheppard, P.

    2014-12-01

    Three years ago we embarked on a project to boost the coverage of palaeosecular variation data from the Southwest Pacific region, and so to provide the means to enhance global and regional field models, dating tools derived from them, and understanding of features of the geodynamo, particularly beneath this region of the Earth's surface. Here we present our progress to date, including lake sediment records covering the entire Holocene, archaeomagnetic data from Maori cooking ("hangi") stones dating back to the earliest occupation of New Zealand, archaeointensities from Lapita pottery from the Pacific Islands (Fiji, Tonga and Papua New Guinea) dating back to ca 3000 BP, and palaeomagnetic directions and intensities from volcanic rocks and lava flows of the North Island of New Zealand. Central to the project is a composite lake sediment record, constrained by a high-resolution radiocarbon-based chronology, which provides a complete record of declination, inclination and relative palaeointensity for New Zealand through the Holocene. This is complemented by directions and absolute intensities from archaeological materials, most of which have associated radiocarbon age control, and lavas with 40Ar-39Ar age constraints, the rock magnetism and analytical details of which are discussed in accompanying posters. The overall picture reveals several large amplitude directional swings in the early Holocene magnetic field, followed by relatively low amplitude secular variation for several thousand years leading to the present trend to increasingly easterly declination and steep inclination as the south magnetic pole moves further off the Antarctic continent towards New Zealand.

  19. Comprehensive spectrum of the ?-Thalassemia mutations in Khuzestan, southwest Iran.

    Science.gov (United States)

    Galehdari, Hamid; Salehi, Bahaoddin; Azmoun, Somaiyeh; Keikhaei, Bijan; Zandian, Khoda Morad; Pedram, Mohammad

    2010-01-01

    ?-Thalassemia (?-thal) is characterized by reduction or absence of ?-globin gene expression. We describe the spectrum of mutations observed in a large cohort of ?-thal carriers in Khuzestan, Southwest Iran. All together 1,241 blood samples from individuals with decreased mean corpuscular volume (MCV) and elevated Hb A(2) levels, were analyzed either by reverse dot-blot or by direct sequencing of the HBB gene. We found 42 different mutations associated with ?-thal and identified eight common ?-globin variants, namely, Hb S [?6(A3)Glu?Val], Hb C [?6(A3)Glu?Lys], Hb D-Punjab [?121(GH4)Glu?Gln] and Hb O-Arab [?121(GH4)Glu?Lys]. No mutations were found in two individuals. The distribution is characteristic of a heterogenous population with three preferential mutations being present [codons 36/37 (-T), IVS-II-1 (G>A) and IVS-I-110 (G>A)] at a frequency of 20.5, 20.0 and 14.2%, respectively, followed by 39 mutations in decreasing frequencies from 5.2 down to 0.1%. These data are of importance when planning prevention strategies in the country. PMID:20854120

  20. Marine debris ingestion by albatrosses in the southwest Atlantic Ocean.

    Science.gov (United States)

    Jiménez, Sebastián; Domingo, Andrés; Brazeiro, Alejandro; Defeo, Omar; Phillips, Richard A

    2015-07-15

    Plastics and other marine debris affect wildlife through entanglement and by ingestion. We assessed the ingestion of marine debris by seven albatross species in the southwest Atlantic by analyzing stomach contents of birds killed in fisheries. Of the 128 specimens examined, including four Diomedea species (n=78) and three Thalassarche species (n=50), 21 (16.4%) contained 1-4 debris items, mainly in the ventriculus. The most common type was plastic fragments. Debris was most frequent in Diomedea species (25.6%) and, particularly, Diomedea sanfordi (38.9%) and very rare in Thalassarche species (2.0%), presumably reflecting differences in foraging behavior or distribution. Frequency of occurrence was significantly higher in male than female Diomedea albatrosses (39.3% vs. 18.0%). Although levels of accumulated debris were relatively low overall, and unlikely to result in gut blockage, associated toxins might nevertheless represent a health risk for Diomedea albatrosses, compounding the negative impact of other human activities on these threatened species. PMID:25986654