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1

Silver behaviour along the salinity gradient of the Gironde Estuary.  

UK PubMed Central (United Kingdom)

Dissolved and particulate Ag concentrations (Ag(D) and Ag(P), respectively) were measured in surface water and suspended particulate matter (SPM) along the salinity gradient of the Gironde Estuary, South West France, during three cruises (2008-2009) covering contrasting hydrological conditions, i.e. two cruises during intermediate and one during high freshwater discharge (~740 and ~2,300 m(3)/s). Silver distribution reflected non-conservative behaviour with 60-70 % of Ag(P) in freshwater particles being desorbed by chlorocomplexation. The amount of Ag(P) desorbed was similar to the so-called reactive, potentially bioavailable Ag(P) fraction (60 ± 4 %) extracted from river SPM by 1 M HCl. Both Ag(P) (0.22 ± 0.05 mg/kg) and Ag(P)/Th(P) (0.025-0.028) in the residual fraction of fluvial and estuarine SPM were similar to those in SPM from the estuary mouth and in coastal sediments from the shelf off the Gironde Estuary, indicating that chlorocomplexation desorbs the reactive Ag(P). The data show that desorption of reactive Ag(P) mainly occurs inside the estuary during low and intermediate discharge, whereas expulsion of partially Ag(P)-depleted SPM (Ag(P)/Th(P) ~0.040) during the flood implies ongoing desorption in the coastal ocean, e.g. in the nearby oyster production areas (Marennes-Oléron Bay). The highest Ag(D) levels (6-8 ng/L) occurred in the mid-salinity range (15-20) of the Gironde Estuary and were decoupled from freshwater discharge. In the maximum turbidity zone, Ag(D) were at minimum, showing that high SPM concentrations (a) induce Ag(D) adsorption in estuarine freshwater and (b) counterbalance Ag(P) desorption in the low salinity range (1-3). Accordingly, Ag behaviour in turbid estuaries appears to be controlled by the balance between salinity and SPM levels. The first estimates of daily Ag(D) net fluxes for the Gironde Estuary (Boyle's method) showed relatively stable theoretical Ag(D) at zero salinity (Ag (D) (0) = 25-30 ng/L) for the contrasting hydrological situations. Accordingly, Ag(D) net fluxes were very similar for the situations with intermediate discharge (1.7 and 1.6 g/day) and clearly higher during the flood (5.0 g/day) despite incomplete desorption. Applying Ag (D) (0) to the annual freshwater inputs provided an annual net Ag(D) flux (0.64-0.89 t/year in 2008 and 0.56-0.77 t/year in 2009) that was 12-50 times greater than the Ag(D) gross flux. This estimate was consistent with net Ag(D) flux estimates obtained from gross Ag(P) flux considering 60 % desorption in the estuarine salinity gradient.

Lanceleur L; Schäfer J; Blanc G; Coynel A; Bossy C; Baudrimont M; Glé C; Larrose A; Renault S; Strady E

2013-03-01

2

Spring phytoplankton assemblages in and around the maximum turbidity zone of the estuaries of the Elbe (Germany), the Schelde (Belgium/The Netherlands) and the Gironde (France)  

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In spring 1993 phytoplankton samples were taken along the longitudinal salinity gradient of the estuaries of the Elbe, Schelde and Gironde. A minimum in phytoplankton abundance, biomass and diversity was observed in the inner to upper reaches of all estuaries, suggesting massive mortality in these z...

Muylaert, K.; Sabbe, K.

3

Carbon isotopic ratio of suspended organic matter of the Gironde estuary. Application to particulate Zn and Pb distribution  

Energy Technology Data Exchange (ETDEWEB)

In the Gironde estuary, the isotopic ratio of particulate organic carbon (P.O.C.), and the ratio metal/P.O.C. indicate the occurrence of two zones. Up-river, the concentration decreases due to the consumption of the organo-metallic phase and by mixing in the ''mud plug'' with terrestrial particles impoverished in metal and P.O.C. Down-stream, the mixing of metal rich terrestrial P.O.C. with poorer marine particles determines the metal concentrations.

Fontugne, M. (Centre des Faibles Radioactivites, C.N.R.S.-C.E.A., Gif-sur-Yvette (France)); Jouanneau, J.M. (Universite Bordeaux-1, Talence (France))

1981-10-12

4

Carbon isotopic ratio of suspended organic matter of the Gironde estuary. Application to particulate Zn and Pb distribution  

International Nuclear Information System (INIS)

In the Gironde estuary, the isotopic ratio of particulate organic carbon (P.O.C.), and the ratio metal/P.O.C. indicate the occurrence of two zones. Up-river, the concentration decreases due to the consumption of the organo-metallic phase and by mixing in the ''mud plug'' with terrestrial particles impoverished in metal and P.O.C. Down-stream, the mixing of metal rich terrestrial P.O.C. with poorer marine particles determines the metal concentrations

1981-10-12

5

Tidal and fluvial controls on the morphological evolution of a lobate estuarine tidal bar: The Plassac Tidal Bar in the Gironde Estuary (France)  

Science.gov (United States)

This study shows the short-term sediment dynamics (2010) and the long-term morphological evolution (1905 to 2008) of a tidal sand bar emplaced in the Gironde Estuary, the Plassac Tidal Bar. This tidal sand bar was selected because it corresponds to a morphological category (lobate shape) that was not previously studied in the setting of estuarine bay-head deltas. A recent high-resolution bathymetric survey (2010) evidences the sediment transport pattern, inferred from the lee face orientation of subaqueous dunes. This sediment transport pattern, together with results from previous studies, explains the five main mechanisms for the tidal bar evolution identified from 29 bathymetric maps since 1905: namely, flood ramp infill, partial ebb shield breaching, lateral accretion of the ebb spits and ebb shield lengthening, generated by the merging of mini-flood lobes on the outer sides of the ebb spits. Lateral accretion seems to be a key-process of sediment accretion for lobate tidal sand bars. Most of the evolutions are explained by tidal processes, but a fluvial influence is evidenced by correlating the presence of mini-flood lobes (migrating seaward from the upper reaches of the bay-head delta) and the lengthening of the tidal bar with periods of high fluvial discharge. A ca. 25-year periodicity in both the fluvial discharge and the tidal bar width, length and volume variations is evidenced and suggests a climate control on the tidal bar evolution. A classification of lobate tidal sand bars is proposed in order to distinguish tide-dominated and wave-influenced sand bars emplaced in large estuary mouth or tidal inlets, from tide-dominated and fluvial-influenced sand bars emplaced in bay-head deltas.

Billy, Julie; Chaumillon, Eric; Féniès, Hugues; Poirier, Clément

2012-10-01

6

Selenium in sediments and biota from estuaries of southwest England.  

UK PubMed Central (United Kingdom)

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?gg(-1) in the Yealm to 1.49?gg(-1) at one site in the Plym. Concentrations in Fucus vesiculosus (0.05-0.31?gg(-1)) and F. ceranoides (0.05-0.51?gg(-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?gg(-1)), Hediste diversicolor (2.82-12.68?gg(-1)), Arenicola marina (?17?gg(-1)) and Scrobicularia plana (1.18-6.85?gg(-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.

Turner A

2013-08-01

7

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

UK PubMed Central (United Kingdom)

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 inflicted by the energy transferred through the tsunami, which disturbed the entire estuarine embayment. However, the post tsunami water quality showed normal levels indicating that the region has recovered from the tsunami impacts.

Laluraj CM; Kesavadas V; Balachandran KK; Gerson VJ; Martin GD; Shaiju P; Revichandran C; Joseph T; Nair M

2007-02-01

8

Biomonitoring of thallium availability in two estuaries of southwest England.  

UK PubMed Central (United Kingdom)

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.

Turner A; Turner D; Braungardt C

2013-04-01

9

VARIABILITES MORPHOLOGIQUE ET DU TAUX D’HORMONE DE CROISSANCE DES CIVELLES D'ANGUILLES EUROPEENNES (Anguilla anguilla) DANS L'ESTUAIRE DE LA GIRONDE AU COURS DE LA SAISON 1997-1998 MORPHOLOGICAL AND GROWTH HORMONE VARIABILITIES OF EUROPEAN GLASS-EEL (Anguilla anguilla) IN GIRONDE ESTUARY DURING 1997-1998 SEASON  

Directory of Open Access Journals (Sweden)

Full Text Available L’objectif de ce travail est de compléter la caractérisation morphologique des civelles entrant dans l’estuaire de la Gironde par un paramètre physiologique, le taux d’hormone de croissance. Le flux d’arrivée a été suivi lors de la saison 1997 – 1998. 303 civelles au stade Vb ont été capturées et analysées individuellement. La longueur et la masse des individus diminuent en février, le facteur de condition seulement en mars. Le taux moyen d’hormone de croissance passe de 6 ng/hypophyse en moyenne en décembre à 16 ng/hypophyse en février et mars pour atteindre 20 ng/hypophyse en avril et mai. L’hypothèse la plus plausible est que cette augmentation du taux d’hormone traduise une détresse physiologique de plus en plus importante des animaux qui arrivent. The aim of this study is to complete the morphological description of Gironde glass eels according to a physiological parameter, the growth hormone. The incoming flux had been observed during the migration season 1997-1998. 303 glass eels of pigmentation stage Vb were caught and individually analysed. The length and the weight of the glass eels decreased in February, the condition factor only in March. The growth hormone rate increased from an average of 6 ng/pituitary in December to an average of 16 ng/pituitary in February and March and up to an average around 20 ng/pituitary in April and May. The most credible hypothesis is that the first incoming glass eels show a smaller distress level than the last ones.

LAMBERT P.; SBAIHI M.; ROCHARD E.; MARCHELIDON J.; DUFOUR S.; ELIE P.

2008-01-01

10

Simulation of potential oyster density with variable freshwater inflow (1965-2000) to the caloosahatchee river estuary, southwest Florida, USA.  

UK PubMed Central (United Kingdom)

Oyster beds are disappearing worldwide through a combination of over-harvesting, diseases, and salinity alterations in the coastal zone. Sensitivity of oysters to variable discharge and salinity is particularly acute in small sub-tropical estuaries subject to regulated freshwater releases. South Florida has sub-tropical estuaries where watershed flood control sometimes results in excessive freshwater inflow to estuaries during the wet season (May-Oct) and reduced discharge and increased salinities in the dry season (Nov-Apr). The potential to reserve freshwater accumulated during the wet season could offer the capacity to regulate freshwater at different temporal scales, thus optimizing salinity conditions for estuarine biota. The goal of this study was to use simulation modeling to explore the effects of freshwater inflows and salinity on adult oyster survival in the Caloosahatchee River Estuary (CRE) in southwest Florida. Water managers derived three different freshwater inflow scenarios for the CRE based on historical and modified watershed attributes for the time period of 1965-2000. Three different salinity time series were generated from the inflow scenarios at each of three sites in the lower CRE and used to conduct nine different oyster simulations. Overall, the predicted densities of adult oysters in the upstream site were 3-4 times greater in seasons that experienced reduced freshwater inflow (e.g., increased salinity) with oyster density in the lower estuary much less influenced by the inflows. Potential storage of freshwater reduced the frequency of extreme flows in the wet season and helped to maintain minimum inflow in the dry season near the estuarine mouth. Analyses of inflows indicated that discharges ranging from 0 to 1,500 cfs could promote favorable salinities of 10-25 in the lower CRE depending on wet versus dry season climatic conditions. This range of inflows is similar to that derived in other studies of the CRE and emphasizes the value of simulation models to help prescribe freshwater releases which benefit estuarine biota.

Buzzelli C; Doering PH; Wan Y; Gorman P; Volety A

2013-10-01

11

Simulation of Potential Oyster Density with Variable Freshwater Inflow (1965-2000) to the Caloosahatchee River Estuary, Southwest Florida, USA  

Science.gov (United States)

Oyster beds are disappearing worldwide through a combination of over-harvesting, diseases, and salinity alterations in the coastal zone. Sensitivity of oysters to variable discharge and salinity is particularly acute in small sub-tropical estuaries subject to regulated freshwater releases. South Florida has sub-tropical estuaries where watershed flood control sometimes results in excessive freshwater inflow to estuaries during the wet season (May-Oct) and reduced discharge and increased salinities in the dry season (Nov-Apr). The potential to reserve freshwater accumulated during the wet season could offer the capacity to regulate freshwater at different temporal scales, thus optimizing salinity conditions for estuarine biota. The goal of this study was to use simulation modeling to explore the effects of freshwater inflows and salinity on adult oyster survival in the Caloosahatchee River Estuary (CRE) in southwest Florida. Water managers derived three different freshwater inflow scenarios for the CRE based on historical and modified watershed attributes for the time period of 1965-2000. Three different salinity time series were generated from the inflow scenarios at each of three sites in the lower CRE and used to conduct nine different oyster simulations. Overall, the predicted densities of adult oysters in the upstream site were 3-4 times greater in seasons that experienced reduced freshwater inflow (e.g., increased salinity) with oyster density in the lower estuary much less influenced by the inflows. Potential storage of freshwater reduced the frequency of extreme flows in the wet season and helped to maintain minimum inflow in the dry season near the estuarine mouth. Analyses of inflows indicated that discharges ranging from 0 to 1,500 cfs could promote favorable salinities of 10-25 in the lower CRE depending on wet versus dry season climatic conditions. This range of inflows is similar to that derived in other studies of the CRE and emphasizes the value of simulation models to help prescribe freshwater releases which benefit estuarine biota.

Buzzelli, Christopher; Doering, Peter H.; Wan, Yongshan; Gorman, Patricia; Volety, Aswani

2013-10-01

12

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

Science.gov (United States)

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

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

2011-06-01

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

Directory of Open Access Journals (Sweden)

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.

G. D. Martin; K. R. Muraleedharan; J. G. Vijay; G. Rejomon; N. V. Madhu; A. Shivaprasad; C. K. Haridevi; M. Nair; K. K. Balachandran; C. Revichandran; K. V. Jayalakshmy; N. Chandramohanakumar

2010-01-01

14

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

Science.gov (United States)

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.

Martin, G. D.; Muraleedharan, K. R.; Vijay, J. G.; Rejomon, G.; Madhu, N. V.; Shivaprasad, A.; Haridevi, C. K.; Nair, M.; Balachandran, K. K.; Revichandran, C.; Jayalakshmy, K. V.; Chandramohanakumar, N.

2010-03-01

15

Comparative spring distribution of zooplankton in three macrotidal European estuaries  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The zooplankton of three european estuaries (Ems, Gironde and Westerschelde) was investigated during spring 1992 by means of samples taken along the salinity gradient. The three estuaries are comparable in terms of total area, flushing time and salinity gradient but differ by their level of eutrophi...

Sautour, B.; Castel, J.

16

Meiobenthic distribution and nematode community structure in five European estuaries  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Meiofauna from the intertidal zone of five European estuaries (Ems, Westerschelde, Somme, Gironde, Tagus) was investigated. Samples represented a cross section of various benthic habitats from near-freshwater to marine, from pure silts to fine-sandy bottoms. The meiobenthic community comprised every...

Soetaert, K.; Vincx, M.; Wittoeck, J.; Tulkens, M.

17

Spatial and temporal variation in seagrass coverage in Southwest Florida: assessing the relative effects of anthropogenic nutrient load reductions and rainfall in four contiguous estuaries.  

Science.gov (United States)

The estuaries of Tampa Bay, Sarasota Bay, Lemon Bay, and Upper Charlotte Harbor are contiguous waterbodies located within the subtropical environment of Southwest Florida. Based on an examination of rainfall data over the period of record (1916-2001) within the watersheds of these estuaries, there is no evidence for spatial differences (at the watershed level) or monotonic trends in annual rainfall. During the 1980s, nitrogen loads into Tampa Bay and Sarasota Bay (generated primarily by domestic wastewater treatment facilities) were reduced by 57% and 46%, respectively. In response, both Tampa Bay and Sarasota Bay have lower phytoplankton concentrations, greater water clarity and more extensive seagrass coverage in 2002 than in the early 1980s. As there is no evidence of a concurrent trend in rainfall during the period of 1982-2001, it is unlikely that variation in rainfall can account for the observed increase in seagrass coverage in these two bays. In contrast, seagrass coverage has remained relatively constant since the mid 1980s in Lemon Bay and Charlotte Harbor. Domestic wastewater treatment facilities are minor sources of nitrogen to Lemon Bay, and water clarity in Charlotte Harbor varies mostly as a function of dissolved organic matter and non-chlorophyll associated turbidity, not phytoplankton levels. Even in estuaries that share boundaries and are within 100 km of each other, varied responses to anthropogenic changes and natural phenomena were observed in water quality and associated seagrass extent. Resource management strategies must take into account system-specific factors-not all strategies will result in similar results in different systems. PMID:16115497

Tomasko, D A; Corbett, C A; Greening, H S; Raulerson, G E

2005-03-23

18

Long-term records of cadmium and silver contamination in sediments and oysters from the Gironde fluvial-estuarine continuum - evidence of changing silver sources.  

UK PubMed Central (United Kingdom)

The Gironde fluvial estuarine system is impacted by historic metal pollution (e.g. Cd, Zn, Hg) and oysters (Crassostrea gigas) from the estuary mouth have shown extremely high Cd concentrations for decades. Based on recent work (Chiffoleau et al., 2005) revealing anomalously high Ag concentrations (up to 65 mg kg(-1); dry weight) in Gironde oysters, we compared long-term (~1955-2001) records of Ag and Cd concentrations in reservoir sediment with the respective concentrations in oysters collected between 1979 and 2010 to identify the origin and historical trend of the recently discovered Ag anomaly. Sediment cores from two reservoirs upstream and downstream from the main metal pollution source provided information on (i) geochemical background (upstream; Ag: ~0.3 mg kg(-1); Cd: ~0.8 mg kg(-1)) and (ii) historical trends in Ag and Cd pollution. The results showed parallel concentration-depth profiles of Ag and Cd supporting a common source and transport. Decreasing concentrations since 1986 (Cd: from 300 to 11 mg kg(-1); Ag: from 6.7 to 0.43 mg kg(-1)) reflected the termination of Zn ore treatment in the Decazeville basin followed by remediation actions. Accordingly, Cd concentrations in oysters decreased after 1988 (from 109 to 26 mg kg(-1), dry weight (dw)), while Ag bioaccumulation increased from 38 up to 116 mg kg(-1), dw after 1993. Based on the Cd/Ag ratio (Cd/Ag~2) in oysters sampled before the termination of zinc ore treatment (1981-1985) and assuming that nearly all Cd in oysters originated from the metal point source, we estimated the respective contribution of Ag from this source to Ag concentrations in oysters. The evolution over the past 30 years clearly suggested that the recent, unexplained Ag concentrations in oysters are due to increasing contributions (>70% after 1999) by other sources, such as photography, electronics and emerging Ag applications/materials.

Lanceleur L; Schäfer J; Chiffoleau JF; Blanc G; Auger D; Renault S; Baudrimont M; Audry S

2011-11-01

19

Long-term records of cadmium and silver contamination in sediments and oysters from the Gironde fluvial-estuarine continuum - evidence of changing silver sources.  

Science.gov (United States)

The Gironde fluvial estuarine system is impacted by historic metal pollution (e.g. Cd, Zn, Hg) and oysters (Crassostrea gigas) from the estuary mouth have shown extremely high Cd concentrations for decades. Based on recent work (Chiffoleau et al., 2005) revealing anomalously high Ag concentrations (up to 65 mg kg(-1); dry weight) in Gironde oysters, we compared long-term (~1955-2001) records of Ag and Cd concentrations in reservoir sediment with the respective concentrations in oysters collected between 1979 and 2010 to identify the origin and historical trend of the recently discovered Ag anomaly. Sediment cores from two reservoirs upstream and downstream from the main metal pollution source provided information on (i) geochemical background (upstream; Ag: ~0.3 mg kg(-1); Cd: ~0.8 mg kg(-1)) and (ii) historical trends in Ag and Cd pollution. The results showed parallel concentration-depth profiles of Ag and Cd supporting a common source and transport. Decreasing concentrations since 1986 (Cd: from 300 to 11 mg kg(-1); Ag: from 6.7 to 0.43 mg kg(-1)) reflected the termination of Zn ore treatment in the Decazeville basin followed by remediation actions. Accordingly, Cd concentrations in oysters decreased after 1988 (from 109 to 26 mg kg(-1), dry weight (dw)), while Ag bioaccumulation increased from 38 up to 116 mg kg(-1), dw after 1993. Based on the Cd/Ag ratio (Cd/Ag~2) in oysters sampled before the termination of zinc ore treatment (1981-1985) and assuming that nearly all Cd in oysters originated from the metal point source, we estimated the respective contribution of Ag from this source to Ag concentrations in oysters. The evolution over the past 30 years clearly suggested that the recent, unexplained Ag concentrations in oysters are due to increasing contributions (>70% after 1999) by other sources, such as photography, electronics and emerging Ag applications/materials. PMID:21868056

Lanceleur, Laurent; Schäfer, Jörg; Chiffoleau, Jean-François; Blanc, Gérard; Auger, Dominique; Renault, Sophie; Baudrimont, Magalie; Audry, Stéphane

2011-08-24

20

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

UK PubMed Central (United Kingdom)

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.

Hierro A; Bolivar JP; Vaca F; Borrego J

2012-08-01

 
 
 
 
21

Responses of Pacific oyster Crassostrea gigas populations to abiotic stress in environmentally contrasted estuaries along the Atlantic coast of France.  

UK PubMed Central (United Kingdom)

Genetic and ecophysiological responses of oyster, Crassostrea gigas, populations to environmental stress were investigated in three highly contaminated French estuaries (the Gironde, Loire and Vilaine) and compared to a control, the Belon estuary. A strong response in both metallothionein CgMT4 mRNA expression, as determined by semi-quantitative RT-PCR, and amount of protein, as determined by ELISA tests, was demonstrated in estuarine populations subjected to differential contamination, with an inhibition in the area most highly contaminated with metals. In these same estuarine populations, we found polymorphisms of the metallothionein CgMT4 gene and three other genes (glutamine synthetase--GS, delta-9 desaturase--D9 and phosphoglucomutase--PGM) involved in stress response of C. gigas. We showed that genetic differentiation was observed for MT4 and PGM genes in the Gironde estuary which is highly contaminated with metals. A strong seasonal effect was observed. Phenotype-genotype coupling revealed that one particular MT4 allele and one PGM allele seemed to be associated with metal sensitivity expressed as lower detoxification efficiency and higher metal bioaccumulation. The MT4 gene is a good physiological and genetic marker of stress response and susceptibility.

David E; Tanguy A; Riso R; Quiniou L; Laroche J; Moraga D

2012-03-01

22

Concentrations of suspended particulate organic carbon in the tidal Yorkshire Ouse River and Humber Estuary.  

Science.gov (United States)

Data are presented for particulate organic carbon (POC) and particulate nitrogen (PN) concentrations in the Humber Estuary and tidal River Ouse Estuary. The POC data were derived from approximately monthly surveys and are consistent with data reported for suspended particulate matter (SPM) in the non-tidal River Ouse (the freshwater river) and with SPM, or bed sediments, in estuarine ecosystems such as the Mississippi, Delaware, San Francisco Bay, Tolo Harbour, the Vellar Estuary and Cochin Backwater, as well as the Loire, Gironde, Ems and Tamar Estuaries. Relative to the dry weight of SPM, the Humber-averaged organic carbon and nitrogen percentages during the year February 1995-March 1996 were 2.6 +/- 0.6% (mean and S.D.) and 0.21 +/- 0.04%, respectively. The ratio of Humber-averaged POC to Humber-averaged PN was 13 +/- 3. Higher POC levels were observed near the Humber's mouth and in the adjacent coastal zone during 'bloom' conditions, and in the upper estuarine reaches during large, winter and springtime freshwater inflows. At these times of high runoff, the POC content of SPM increased progressively up-estuary from the coastal zone to the tidal River Ouse. When inflows became very low, during late spring to early autumn of 1995, both the freshwater-saltwater interface (FSI) and the strengthening turbidity maximum (TM) moved further up-estuary and the POC content of SPM in the upper reaches of the Ouse became lower compared with that immediately down-estuary. This led to a poorly defined POC maximum near the confluence of the Humber, Ouse and Trent, before POC eventually decreased again towards the coastal zone. The lower POC contents in the upper estuarine reaches of the tidal Ouse may have been partly due to POC respiration by heterotrophic bacteria attached to SPM within the TM, consistent with the severe oxygen depletion observed there during high turbidity, summertime spring tides. PMID:10847164

Uncles, R J; Frickers, P E; Easton, A E; Griffiths, M L; Harris, C; Howland, R J; King, R S; Morris, A W; Plummer, D H; Tappin, A D

2000-05-01

23

THE EFFICIENCY OF SELECTIVE TIDAL STREAM TRANSPORT IN GLASS EEL ENTERING THE GIRONDE (FRANCE) EFFICACITÉ DE LA MIGRATION DES CIVELLES ENTRANT DANS LE BASSIN DE LA GIRONDE EN UTILISANT UN TRANSPORT SÉLECTIF TIDAL  

Directory of Open Access Journals (Sweden)

Full Text Available Traditional estimation of migration speed is based on telemetry or marking of individual fish. Only a few numbers of fishes (or batches) are followed, often over short periods of time. We propose a method based on capture data from the professional fishery. It is applied to glass eel (Anguilla anguilla) in the Gironde basin (France). Migration speed is estimated using 2 methods: a rough method based on the analysis of seasonal abundance peaks for two métiers and a more precise method of cross-correlation, which compares speeds between several fishing areas. The methods are coherent and lead to mean migration speed ranging from 3 to 4 km/day. We define an index of efficiency of migration using selective tidal stream transport (STST efficiency index) as the ratio of the observed migration speed to the potential speed (flood tide current speed and swimming speed). For the glass eel in the Gironde basin this index ranges between 0.15 and 0.19. The glass eel behavior, which can explain this low value, is reviewed. Our STST efficiency index can be successfully applied for many fish or crustaceans using selective tidal stream transport. It can also be used for one species to compare results obtained on different basins. Les méthodes traditionnelles d’estimation de la vitesse de migration reposent sur la télémétrie ou les techniques de marquage. Seulement un nombre restreint de poissons (ou lots de poissons) sont ainsi suivis, souvent sur un temps court. Nous proposons une méthode basée sur les données de capture de la pêcherie professionnelle. Elle est appliquée au cas de la migration de la civelle (Anguilla anguilla) dans le bassin de la Gironde (France). La vitesse de migration est estimée grâce à deux méthodes : une méthode grossière basée sur l’étude des pics saisonniers d’abondance de deux métiers de pêche ; une méthode plus précise utilisant les corrélations croisées qui permet de comparer des vitesses de migration entre plusieurs zones de pêche du bassin. Les résultats des deux méthodes sont cohérents et conduisent à une vitesse moyenne de migration de l’ordre de 3 à 4 km/jour. Nous calculons un indice d’efficacité de la migration utilisant le transport sélectif tidal (STST efficiency index) qui est la vitesse réelle des civelles divisée par une vitesse potentielle (la somme de la vitesse des courants de flot et de la vitesse de nage). Pour le bassin de la Gironde, cet indice est compris entre 0,15 et 0,19. Les comportements de la civelle qui peuvent expliquer ces faibles valeurs, sont passés en revue. Notre indice et nos méthodes peuvent être employés pour de nombreuses espèces de poissons et de crustacés qui utilisent le transport sélectif tidal. Il peut également être utilisé pour une espèce donnée pour comparer les résultats obtenus sur différents bassins.

BEAULATON L.; CASTELNAUD G.

2008-01-01

24

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

UK PubMed Central (United Kingdom)

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

Laroche J; Gauthier O; Quiniou L; Devaux A; Bony S; Evrard E; Cachot J; Chérel Y; Larcher T; Riso R; Pichereau V; Devier MH; Budzinski H

2013-02-01

25

Estuary Data Mapper  

Science.gov (United States)

The U.S. Environmental Protection Agency (US EPA) is developing e-Estuary, a decision-support system for coastal management. E-Estuary has three elements: an estuarine geo-referenced relational database, watershed GIS coverages, and tools to support decision-making. To facilita...

26

Estuary Classification Revisited  

CERN Multimedia

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.

Guha, Anirban

2012-01-01

27

Preserving Southwest Virginia's Folklore.  

Science.gov (United States)

Describes Southwest Virginia's rich tradition of folklore and culture and the need for its preservation. Summarizes the author's time-consuming process of preparing an inventory and indexing the vast archival collections gathered by students in American Folklore classes at Mountain Empire Community College and by the Southwest Virginia Folklore…

Burgin, Ramond

1997-01-01

28

ÂGE À LA MIGRATION DE REPRODUCTION DES GÉNITEURS DE TROIS COHORTES DE GRANDES ALOSES (ALOSA ALOSA) DANS LE BASSIN VERSANT DE LA GARONNE (FRANCE). AGE OF MIGRATION FOR SPAWNERS FROM THREE COHORTS OF ALLIS SHAD (ALOSA ALOSA) IN THE GIRONDE WATERSHED (FRANCE)  

Directory of Open Access Journals (Sweden)

Full Text Available La population de grandes aloses (Alosa alosa) du bassin versant de la Garonne est encore abondante. L’importance et la structure des flux de migration 1994, 1995 et 1996 ont été estimées à partir du suivi des captures de la pêcherie et des passages au niveau d’un obstacle. Des campagnes d’échantillonnage précisent les caractéristiques biologiques des individus. La force des cohortes 1989, 1990 et 1991 est basée sur le suivi des abondances mensuelles des alosons en estuaire. A partir de ces informations, il a été possible, pour les cohortes 1989 à 1991, de rapporter les effectifs de géniteurs d’un sexe donné, remontant à un âge donné au nombre d’alosons présents en estuaire lors de leur première année. C’est à 5 ans que remonte le maximum de géniteurs, mâles comme femelles. En moyenne, 5,26 % des alosons en estuaire donnent des femelles de 5 ans et 4,89 % des mâles de 5 ans. Le patron de migration pour les géniteurs de 4 et 6 ans diffère selon le sexe : 2,61 % des alosons en estuaire deviendront des géniteurs mâles de 4 ans et 0,73 % des mâles de 6 ans. 0,99 % et 2,08 % des alosons en estuaire donneront respectivement des femelles de 4 et 6 ans. Les entrées de géniteurs de 3 ans et 7 ans restent inférieures à 0,2 % pour les deux sexes. Globalement, 8,40 % des alosons deviennent des géniteurs femelles, 8,33 % des géniteurs mâles. A noter enfin la forte variabilité de la proportion globale de femelle issue d’une cohorte. 51,0 % des géniteurs de la cohorte 1989 étaient des femelles, 56,8 % pour la cohorte 1990 et seulement 40,9 % pour la cohorte 1991. The population of allis shad (Alosa alosa) of the Gironde watershed is still abundant. The abundance and the structure were estimated for the runs 1994, 1995 and 1996. These estimations are based on surveys and samplings (i) of the captures of the fisheries and (ii) of the passages in fish lift. The strength of the cohorts 1989, 1990 and 1991 was evaluated according to the follow-up of monthly abundance of juveniles in estuary. With this information, it was possible, for the cohorts 1989 to 1991, to calculate the ratio between the number of spawner of one sex, migrating at one age and the number of young of the year (yoy) in estuary. Maximum of the spawners, males as females, migrate at age 5. On average, 5.26 % of the yoy in estuary will become 5 years old female spawners of and 4.89 % 5 years old male spawner. The migration pattern for the adults of 4 and 6 years is different according to the sex. 2.61 % of yoy in estuary will become 4 years old male spawners and 0.73 % 6 years old males. 0.99 % and 2.08 % of the juveniles in estuary will respectively give females of 4 and 6 years. The entrance of 3 years and 7 year old spawners remain lower than 0.2 % for the two sexes. Globally, 8.40 % of the yoy in estuary become female spawners, 8.33 % male spawners. Finally, notice the strong variability of the total proportion of female produced by a cohort. 51.0 % of the spawners from the cohort 1989 were females, 56.8 % from the cohort 1990 and only 40.9 % from the cohort 1991.

LAMBERT P.; MARTIN VANDEMBULCKE D.; ROCHARD E.; BELLARIVA J. L.; CASTELNAUD G.

2008-01-01

29

Ecology of estuaries  

International Nuclear Information System (INIS)

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

1992-01-01

30

Ecology of estuaries  

Energy Technology Data Exchange (ETDEWEB)

This book is a summary of information available on estuarine ecology, that reviews concepts and problems of estuaries and assesses the value of these coastal systems. It investigates such topics as water circulation and mixing, trace elements, nutrients, organic matter, and sedimentary processes, with reviews on more than two decades of intense study. Chapters reflect contributions from a variety of interdisciplinary sciences including botany, chemistry, ecology, geology, physics, and zoology.

Kennish, M.J.

1986-01-01

31

Wader migration and distribution in South West estuaries (in relation to the Severn Barrage). V. 1  

Energy Technology Data Exchange (ETDEWEB)

A study has been undertaken with three main objectives: 1. to identify the origins and movement patterns of waders and wildfowl using the River Severn. 2. to evaluate the patterns of low tide usage of the estuary by waders and Shelduck and to identify preferred areas. 3. to evaluate the capacity of adjacent estuaries to absorb any waders displaced from the Severn by a barrage. These objectives were achieved by both computer analysis of existing British Trust for Ornithology data and the collection of new field data. Overall four key species (Shelduck, Dunlin, Curlew and Redshank) occurring in internationally important numbers on the Severn are identified as most likely to be adversely affected by a barrage. It is unlikely that displaced birds of these species could be absorbed by other estuaries in southwest Britain.

1989-01-01

32

Fish assemblages of small estuaries of the Portuguese coast: A functional approach  

Science.gov (United States)

The importance of estuaries for coastal environments is widely acknowledged but their role, structure and ecological status have been the focus of recent scientific efforts mainly concerning large estuarine areas. In this work we used fish assemblages to establish, for the first time, the functional and ecological role of five small estuarine systems along the Portuguese south and southwest coasts. Our results showed that, at a functional approach, fish communities did not differ between estuaries, and that all systems presented a seasonal pattern in diversity values, ecological and feeding guilds. These small estuaries contribute to the support of coastal fish populations by providing temporary habitats to the critical life stages of marine species, shelter and feeding grounds, and should be considered in an ecological and conservation perspective.

Cardoso, Inês; França, Susana; Pais, Miguel Pessanha; Henriques, Sofia; Cancela da Fonseca, Luis; Cabral, Henrique N.

2011-05-01

33

Levels and spatial distribution of polycyclic aromatic hydrocarbons (PAHs) in sediments from Lenga Estuary, central Chile.  

UK PubMed Central (United Kingdom)

The Lenga Estuary is a small brackish wetland located southwest of San Vicente Bay, Region VIII, Chile. Surface sediment from nine sites in the estuary were analysed for PAHs and compared to Sediment Quality Guidelines (SQG). Sediment samples were freeze dried and soxhlet extracted for 16 h using DCM. Identification and quantification was carried out by HPLC. Organic carbon was also determined. Results showed total PAH concentrations ranged from 290 to 6118 (2025 ± 1975)ng g(-1) d.w. (2025 ± 1975). Results for organic carbon percentages ranged from 1% to 7%. Statistical analysis showed a significant positive correlation (Pearson test) between organic carbon percentage PAHs. Comparison of contaminant levels and international Sediment Quality Guidelines (SQG) (ERL and ER) suggested that sediment of the Lenga estuary did not show any ecotoxicological risk for benthic organisms where high levels of PAHs were detected. Monitoring of this and other contaminants is recommended in Chile.

Pozo K; Perra G; Menchi V; Urrutia R; Parra O; Rudolph A; Focardi S

2011-07-01

34

ANALYSE DE LA TENDANCE DE L’ABONDANCE DE L’ALOSE ALOSA ALOSA EN GIRONDE À PARTIR DE L’ESTIMATION D’INDICATEURS HALIEUTIQUES SUR LA PÉRIODE 1977-1998. ABUNDANCE TREND ANALYSIS OF THE ALLIS SHAD ALOSA ALOSA IN THE GIRONDE BASIN DURING THE 1977-1998 PERIOD ON THE BASIS OF ESTIMATED FISHING INDICATORS  

Directory of Open Access Journals (Sweden)

Full Text Available Au cours des deux dernières décennies, la population d’alose vraie Alosa alosa a été considérée par différents auteurs en diminution, même vouée à la disparition, puis en progression, ou se maintenant à un haut niveau d’effectif dans le bassin de la Garonne. L’objectif de ce travail est de produire les indicateurs halieutiques les plus aptes à rendre compte de la tendance de l’abondance de l’alose vraie en Gironde sur la période 1977-1998. Ces indicateurs saisonniers sont d’une part la CPUE et d’autre part la production totale et l’effort total qui doivent permettre d’expliciter et de conforter le diagnostic sur la tendance de l’abondance. L’échantillon non-aléatoire de données de capture et d’effort provenant d’un réseau de pêcheurs coopératifs, a été stratifié selon les métiers de pêche, les zones de pêche et les quinzaines de pêche. L’estimation des captures totales et des efforts totaux fait appel à la théorie classique de l’échantillonnage avec stratification. Afin d’obtenir un indice qui reflète le mieux possible les variations d’abondance inter-annuelles et qui limite l’incidence des variations de capturabilité dans l’espace et dans le temps, nous avons utilisé la théorie du Modèle Linéaire Général pour construire un modèle log-linéaire qui donne le même poids aux zones et aux quinzaines de pêche sur toute la période d’étude. Le modèle explique la CPUE comme l’addition des effets principaux des facteurs zone, année et quinzaine. Une évolution en paliers des indices d’abondance est testée grâce à un modèle à erreur auto-régressive. On constate que les paliers sont très hautement significatifs pour la Gironde et les trois compartiments Estuaire, Garonne, Dordogne. L’analyse des trois indicateurs halieutique et la confrontation de leur évolution nous amènent à conclure que l’abondance d’A. alosa est au minimum stable en Gironde et qu’elle a très certainement augmenté au cours de la période 1977-1998. Le saut des indices d’abondance observé en 1994 peut être rapporté à l’effet de la mise en place des passes et ascenseurs à poissons sur les parties amont de Garonne et Dordogne. Ces résultats encourageants ne doivent pas dissuader les gestionnaires d’adopter une approche prudente de la population d’alose dans le bassin de la Garonne, compte tenu du statut de cette espèce en Europe. The population of the allis shad Alosa alosa has been considered successively in the last twenty years as declining, endangered, increasing, in a satisfactory status. The objective of this study is to estimate the most appropriate fishing indicators which can allow us to state on the abundance trend of Alosa alosa during the 1977-1998 period. These fishing indicators are CPUE, total catch and total fishing effort. The non-random sample of data provided by a group of cooperative fishermen has been stratified with fishing techniques, fishing area, fortnight periods of fishing. The estimate of total catches and total efforts is based on the classical theory of stratified sampling. We used the General Linear Model method to obtain CPUE from a log-linear model, which limits the effects of the variations of capturability in space and time. These CPUE are supposed to be representative of the inter-annual variation of abundance. The model explains the CPUE as the addition of the main effects of the factors zone, year and fortnight. The trend of the abundance indexes is modeled by a step function with an autoregressive error model. The plateaus appear to be very highly significant for the Gironde basin as well as for the sections Estuaire, Garonne, Dordogne. The analysis of the three fishing indicators and the comparison of their evolution lead to the conclusion that the abundance of Alosa alosa is at least stable and has certainly increased in the Gironde basin. The jump of the CPUE observed in 1994 can be related to the construction of fishways in the upper parts of the Garonne and Dordogne rivers. These e

CASTELNAUD G.; ROCHARD E.; LE GAT Y.

2008-01-01

35

Stockholm Southwest field  

Energy Technology Data Exchange (ETDEWEB)

The Stockholm Southwest (SW) field, discovered by Texas Oil and Gas Production Corporation in March 1979, is located in southwest Wallace and northwest Greeley Counties, Kansas, and eastern Cheyenne County, Colorado. It consists of 87 original oil wells which have produced 5.5 million bbl of oil. As of the middle of 1989, it was producing almost 1,200 bbl oil/day from 66 active wells. Regionally, the Stockholm, SW field is situated on a stable Paleozoic platform which extended north from the Anadarko basin. During the early late Morrowan time, there was a significant regression of the Anadarko sea. The subsequent Stockholm fluvial system created an erosional valley which was later back-filled with fluvial and estuarine sediments during transgressions of the Anadarko sea. Regionally, the upper Morrow section is approximately 85 ft (26.2 m) thick, whereas it is approximately 150 ft (46.2 m) thick in the Stockholm Valley. This striking thick can be mapped seismically. Subsequent valley system subparalleled the preexisting Stockholm Valley system, depositing the overlying Johannes sandstone, which is a secondary pay at Stockholm SW. Since the discovery of Stockholm SW field, subsequent exploration activity has extended the productive trend five townships in a north-south direction along the Colorado/Kansas border. This activity has led to the discovery of eight new oil fields. Conservative engineering estimates indicate approximately 170 million bbl of oil in place in the entire trend.

Miller, W.A. (Pacific Enterprises Oil Co., Denver, CO (United States)); Hundley-Goff, E.M. (Marathon Oil Co., Houston, TX (United States)); Veal, S.L. (DCX Resources, Denver, CO (United States)); Brown, L.G.

1991-08-01

36

¡Salud! Southwest Tour  

Directory of Open Access Journals (Sweden)

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.

Joanna Mae Mae Souers

2009-01-01

37

Behaviour of arsenic on the continental shelf off the Gironde estuary: role of phytoplankton in vertical fluxes during spring bloom conditions Comportement de l'arsenic sur le plateau continental au large de l'estuaire de la Gironde : role du phytoplancton dans le flux vertical en situation de bloom printanier.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The arsenic (As) cycle in the marine environment is known to be sensitive to biological activity. Within the scope of the National Coastal Oceanography Program, we undertook a specific study of the behaviour of this element in a water column on the continental shelf of the Bay of Biscay off the Giro...

Michel Pierre; Boutier Bernard; Herbland Alain; Averty Bernard; Artigas Luis Felipe; Auger Dominique; Chartier Emmanuelle

38

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

UK PubMed Central (United Kingdom)

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

Rainbow PS; Kriefman S; Smith BD; Luoma SN

2011-03-01

39

Carbon dioxide emission from european estuaries  

UK PubMed Central (United Kingdom)

The partial pressure of carbon dioxide (pCO2) in surface waters and related atmospheric exchanges were measured in nine European estuaries. Averaged fluxes over the entire estuaries are usually in the range of 0.1 to 0.5 mole of CO2 per square meter per day. For wide estuaries, net daily fluxes to the atmosphere amount to several hundred tons of carbon (up to 790 tons of carbon per day in the Scheldt estuary). European estuaries emit between 30 and 60 million tons of carbon per year to the atmosphere, representing 5 to 10% of present anthropogenic CO2 emissions for Western Europe.

Frankignoulle M; Abril G; Borges A; Bourge I I; Canon C; Delille B; Libert E; Theate JM

1998-10-01

40

Oil spill trajectory analysis for the Calcasieu Estuary  

Energy Technology Data Exchange (ETDEWEB)

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.

Meselhe, E.A. [Louisiana Univ., Lafayette, LA (United States); Barker, C.H.; Hodges, M. [National Oceanic Atmospheric Administration, Seattle, WA (United States)

2001-07-01

 
 
 
 
41

Oil spill trajectory analysis for the Calcasieu Estuary  

International Nuclear Information System (INIS)

[en] 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

2001-01-01

42

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

International Nuclear Information System (INIS)

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

1991-01-01

43

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

Energy Technology Data Exchange (ETDEWEB)

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

Goss-Custard, J.D.; McGrorty, S.; Clarke, R.T.; Pearson, B.; Rispin, W.E.; Durell, S.E.A. le V. dit; Rose, R.J. (Inst. of Terrestrial Ecology, Wareham (United Kingdom)); Warwick, R.M. (Plymouth Marine Lab. (United Kingdom)); Kirby, R. (Ravensrodd Consultants Ltd., Taunton (United Kingdom))

1991-12-01

44

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

International Nuclear Information System (INIS)

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

2007-01-01

45

Birds of the Severn Estuary and Bristol Channel: their current status and key environmental issues.  

UK PubMed Central (United Kingdom)

The Severn Estuary and Bristol Channel encompass a number of designated sites supporting populations of waterbirds and seabirds that are of national or international importance, including the Severn Estuary and Burry Inlet Special Protection Areas (SPAs)/Ramsar Sites and Carmarthen Bay, the UK's first marine SPA. Here, we provide an overview of the present numbers and trends of the waterbirds and seabirds using these sites, updating previous reviews undertaken prior to these designations. We further provide a summary of the main issues that have affected the status of the area's bird populations. Declines in the numbers of waders on the Severn Estuary and the southwest over the last two decades have been linked to climate change. The Sea Empress oil-spill impacted both breeding seabirds and the wintering Common Scoters in Carmarthen Bay, though numbers of the latter recovered 3years after the spill. At the Burry Inlet, Oystercatcher numbers have fallen over the last 25years and considerable research has been undertaken into the conflict with cockle and mussel fisheries. A long-term study at Cardiff Bay, at the mouth of the Severn, revealed a significant impact on the survival of Redshanks following its impoundment and has helped to further understanding of responses of waterbirds to estuarine habitat loss. The potential impacts of the construction of a tidal power scheme on the Severn Estuary are also discussed.

Burton NH; Musgrove AJ; Rehfisch MM; Clark NA

2010-01-01

46

Arsenic speciation in river and estuarine waters from southwest Spain.  

Science.gov (United States)

An arsenic speciation survey was carried out in water samples from the Tinto and Odiel Rivers (southwest of Spain), as well as their common estuary. Both rivers are affected by acid mine drainage (AMD) and represent an input of heavy metals into the estuary, which also suffers from industrial water discharges. Samples were taken in December 2000 and July 2001. The arsenic species considered were arsenite (As(III)), arsenate (As(V)), monomethylarsonic (MMA) and dimethylarsinic (DMA) ions using coupled high-performance liquid chromatography-hydride generation-inductively coupled plasma-mass spectrometry (HPLC-HG-ICP-MS) for their determination. Parameters such as pH, salinity, redox potential and dissolved O2 were also measured. The results revealed that the acid mine drainage originating mainly during winter along the upper part of the Tinto River course causes high inorganic concentrations of dissolved arsenic, up to 600 microg l(-1) of As(III) and 200 microg l(-1) of As(V). In summer, As(III) levels decreased due to the diminution of the input from acid mine drainage and also because of oxidation, with a corresponding increase of As(V) level. Furthermore, the extreme acidic conditions of this river (pH 2.3-2-6) do not allow biological activity sufficient to produce significant concentrations of methylated arsenic species. The arsenic concentrations in the nearby Odiel River were always 5-10 times lower than in the Tinto River, with arsenic levels usually below 100 microg l(-1), dominated by As(V), indicating that it is less affected by acid mine drainage. The highest inorganic arsenic species concentrations were found where the river crosses a mining site, which corresponds to the highest As(III) values. Significant biological activity in this river produced methylated species that were detected along the water-course, with the highest concentrations at the lower course of the river, accounting for up to 53-61% of the total dissolved arsenic. At the common estuary formed by both rivers, only arsenate was detected in most samples at lower concentrations than in the riverine water samples. The tidal cycle showed a similar pattern of dilution of the arsenate when seawater comes into the estuary. Methylated species were not found either in summer or winter, at least at the 0.1 microg l(-1) level, possibly because of the high turbidity of the waters, producing an inhibition of the phytoplankton activity. In addition to the riverine inputs into the common estuary, industrial activity also represents an important source of arsenic as the discharge from a Cu smelter produced the highest arsenate level of all samples in estuary and also the only sample with significant arsenite concentration. Furthermore, the underlying iron-oxide-rich sediments represent an importance source of arsenic into the water column. In three nearby estuaries not affected by industrial activity or acid mine drainage, arsenic levels remained below detection limits. PMID:15919540

Sánchez-Rodas, Daniel; Luis Gómez-Ariza, José; Giráldez, Inmaculada; Velasco, Alfredo; Morales, Emilio

2005-06-01

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Sediment transport pathways in a dredged ria system, southwest England  

Science.gov (United States)

The Fowey Ria system, southwest England, comprises the River Fowey catchment, the Fowey estuary, the cliffs and bays adjacent to the ria mouth, and part of the inner continental shelf of the English Channel. Previously, large quantities of sediment were introduced into the upper ria by ore mining activity. Today, in common with other rias, the Fowey receives a low riverine sediment input. Material from maintenance dredging in the lower ria is dumped in a spoil ground outside the ria mouth. The sediments of the system are investigated using an integrated approach to determine sediment distribution and sediment transport pathways. Surface sediments are analysed for grain size and mineralogy. Grain size trend analysis is used to examine sediment dispersal patterns away from the locus of deposition in the spoil ground. Archived data are used to investigate the seabed morphology and to determine long-term (100 year) bathymetric changes. Within the ria, mixing of sediment from several sources occurs. In the upper reaches, riverine and locally-eroded sediment is transported seawards towards the main area of commercial activity. Sand and finer-grained material moves into the ria from offshore. The bed of the inner continental shelf comprises interfluves covered by a thin veneer of sediment, with a natural composition of locally-derived lithic fragments and biogenic material. The area is mainly low/non-depositional in character, except within the partially-infilled palaeovalley and its tributaries. Sediments dumped in the spoil ground disperse in a complex pattern: coarse-grained material is moved by the action of waves and tidal currents towards the southwest and northeast; fine-grained material is transported either to the east or the west, depending upon the prevailing wave and tidal current regime. Because of its geomorphology, the lower ria acts as an efficient sediment trap, retaining (a) riverine material and sediment eroded from the upper reaches; and (b) sediment entering the ria from offshore. Despite being subjected to major anthropogenic disturbance from past mining and present-day dredging activities, the Fowey Ria conforms to the general sediment model for southwest England rias [Castaing, P., Guilcher, A., 1995. Geomorphology and sedimentology of rias. In: Perillo, G.M.E. (Ed.), Geomorphology and Sedimentology of Estuaries Developments in Sedimentology, No. 53. Elsevier Science, Amsterdam, pp. 69 111]. A conceptual model of sediment transport pathways for the Fowey Ria system is presented as the basis for further investigations.

Friend, P. L.; Velegrakis, A. F.; Weatherston, P. D.; Collins, M. B.

2006-04-01

48

Sea level variability in South African estuaries  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english 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 fluctuatio (more) ns, 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.

Schumann, Eckart H.

2013-01-01

49

General description of the Scheldt estuary  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A general description of the Scheldt estuary, including the hydrology, the sediment transport, the productivity and the biodegradation with respect to their influence on the trace metal behaviour in the Scheldt estuary, is given. The river basin can be divided in several sections according to their ...

Baeyens, W.F.J.; Van Eck, B.T.M.; Lambert, C.; Wollast, R.; Goeyens, L.

50

Suspended matter in the Scheldt estuary  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The Scheldt estuary is characterised by a specific energy pattern resulting from the interaction of wave energy, tidal energy and river energy. It divides the estuary into three parts and governs suspended matter transport and distribution pattern. Observation of suspended matter transport shows the...

Chen, M.S.; Wartel, S.; Van Eck, B.T.M.; van Maldegem, D.

51

Estimation of persistent pollutants in estuaries  

Energy Technology Data Exchange (ETDEWEB)

Synthetic organic compounds, such as pesticides, plasticizers and technical products could be identified and quantified in German estuaries. Processes of biodegradation and sorption are essentially responsible for most of the compounds. Heterotrophic activities are declining down the estuaries to arrive at very low levels in the open sea. Measurements of a number of organic contaminants in the estuaries of the rivers Weser and Elbe as well as in adjacent coastal waters reveal that the estuarine degradation potential is not sufficient to eliminate these compounds.

Ernst, W.

1988-03-01

52

Water quality in the Knysna estuary  

Directory of Open Access Journals (Sweden)

Full Text Available Measurements of water temperature, salinity, pH, dissolved oxygen, secchi disk depth, turbidity and total suspended solids were taken monthly in the Knysna estuary between 1991 and 1994. Measurements of turbidity and total suspended solids of waters entering the Knysna estuary via rivers and man-made inlets were also taken on an ad hoc basis. These results are described and compared to published data on past water quality conditions. No clear long-term changes in water quality in the estuary were evident. High inputs of sediments from minor catchments indicate the necessity for remedial actions.

I.A. Russell

1996-01-01

53

US Environmental Protection Agency: National Estuary Program  

Science.gov (United States)

Established in 1987 by amendments to the Clean Water Act and administered by the Environmental Protection Agency's Office of Wetlands, Oceans, and Watersheds (OWOW), the National Estuary Program (NEP) identifies, restores and protects estuaries along the coasts of the United States. Unlike the traditional regulatory approaches to environmental protection, the NEP targets a wide range of issues and engages local communities in the process. At the site users can find descriptions of the NEP, specific NEP projects, estuaries involved in the NEP (including location, size, presence of threatened and endangered species, major habitat types, etc.), a current awareness section, links to related sites, and the full text of NEP's newsletter, Coastlines.

54

Migration des civelles d'anguilles (Anguilla anguilla L.) dans les estuaires, modalités du phénomène et caractéristiques des individus Civelle (Anguilla anguilla L.) migration in estuaries, process and specimens characteristics  

Directory of Open Access Journals (Sweden)

Full Text Available Nous avons réalisé une analyse de la littérature consacrée à la migration estuarienne de la civelle d'anguille (Anguilla anguilla L.) et nous l'avons confrontée à des chroniques de données originales (abondance, structure en poids et en stades pigmentaires) issues de l'estuaire de la Gironde. Ceci nous a permis de dégager la façon dont se déroule la migration. Il en ressort que les modalités du déroulement de la migration sont bien connues et relativement stables d'une année à l'autre, mais nous en sommes encore réduits à des hypothèses en ce qui concerne l'explication de son allure générale et de sa variabilité interannuelle. L'analyse des caractéristiques des individus montre une haute régularité interannuelle, on peut même parler d'un patron standard de l'évolution des individus en migration. L'action des principaux facteurs environnementaux sur les individus en migration apparaît assez nette, même si nous ne sommes pas en mesure actuellement de hiérarchiser leurs effets sur des flux migrants. Ce travail met en évidence la nécessité, pour appréhender les phénomènes migratoires et à plus forte raison pour établir un prémodèle de migration, de tenir compte de l'ensemble des aspects de la migration (tendance, facteurs modulateurs, épiphénomènes et caractéristiques des individus e n migration) et d'utiliser des horloges écologiques adaptées. We achieved a book review about the estuarine migration of the eel civelle (Anguilla anguilla L.) and we compared the results of this synthesis to unpublished data time series (abundance, weight and pigmentation stages structure) from the Gironde estuary. That enables us to draw the main features of the migration progress, most of them seem to be quite regular even though we can not assume which process induces the shape of the phenomenon and the interyear variability. The analysis of the civelles characteristics show a high interyear regularity of their evolution from the beginning to the end of the season, that constitutes a standard pattern. We have a good knowledge about the main environmental factors which influence the civelle migration, and even if we can assume the way they play we can not form them into a hierarchy. This paper points out the necessity to get a better understanding of the migration to take into account all the features of the phenomenon and to use a biological clock.

ELIE P.; ROCHARD E.

2008-01-01

55

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

Science.gov (United States)

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.

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

2013-03-01

56

Rare, threatened, and endangered vertebrates of southwest Florida and potential OCS activity impacts  

Energy Technology Data Exchange (ETDEWEB)

The eight southwestern Florida counties include populations of 68 vertebrates considered in this report as rare, threatened, or endangered. The terrestrial and near-shore habitats of the study area and the habitat preferences of each of the 68 vertebrates are described. Each vertebrate is listed in the habitats it occupies, and information about reproduction, feeding, and where available, population estimates, is given under the habitat considered most important for each species. The distributions of the rare, threatened and endangered vertebrates by county and habitat demonstrate the relative importance of the southernmost counties (Monroe and Collier) and wetland and coastal habitats (strand, mangrove/marsh, estuaries). Activities contributing to the decline of these 68 vertebrates are assessed and habitat loss is overwhelmingly more important for all. Potential impacts of OCS development are assessed by estimating the effects OCS activities might have on various habitats. Direct impact of OCS development is estimated to be small. Oil spills are considered the most dangerous result of development and the habitats continguous with marine waters (strand, mangrove/marsh, estuaries) are the most susceptible to damage. These are also the habitats identified as harboring the largest, number of rare and endangered vertebrates in southwest Florida.

Woolfenden, G.E.

1983-02-01

57

Tidal currents assessment in the Tagus estuary  

Energy Technology Data Exchange (ETDEWEB)

The authors present in this paper the results of an initial assessment of the potential of tidal currents to generate energy in the Tagus estuary. The work is divided into three phases. The first phase comprises the setting up and calibration of a detailed finite element model for the estuary starting in the ocean boundary. The model was calibrated and verified using water levels and current velocities for several measuring stations within the estuary. The measuring campaign took place in 1987 and was performed by Instituto Hidrografico of the Portuguese Navy. The records are of good quality and cover a period of spring and neap tides. The model give clear indication about the flow pattern within the estuary showing the places were high current velocities are likely to occur. Calculation of the tidal power on selected locations was made. The second phase consisted on the study of the requirements of tidal turbines in terms of site conditions: mainly the minimum water depth and current velocity required for installation. In addition a review was made to understand the development of tidal turbine technology. Three types of turbines were selected as having potential for the site, which usually are associated with moderate current velocity. The third and final phase was the study of the estuary 'map-use' through the construction of a GIS system that allows the identification of locations of potential conflict.

Mendonca, A. (CEHIDRO, Instituto Superior Tecnico, Av. Rovisco Pais, Lisboa, (PT)); Trigo Teixeira, A. (Department of Civil Engineering and Architecture, Instituto Superior Tecnico, Technical University of Lisbon, Av. Rovisco Pais, Lisboa (PT))

2007-07-01

58

Estuaries and coastal waters need help  

Energy Technology Data Exchange (ETDEWEB)

For years, our marine environments-estuaries, coastal waters, and the open ocean-have been used extensively by coastal communities and industries for the disposal of various wastes. Historically, marine waste disposal has been relatively cheap and has solved some short-term waste-management problems; however, its consequences include a general trend toward environmental degradation, particularly in estuaries and coastal waters. Thus, without protective measures, the next few decades will witness degradation in many estuaries and some coastal waters around the country. The extent of current degradation varies greatly around the country. Although it is difficult to ascertain cause and effect relationships, enough evidence exists to conclude that the pollutants in question include disease-causing microorganisms, oxygen-demanding substances, particulate material, metals, and organic chemicals. Two statutes form the basis of most federal regulatory efforts to combat marine pollution: the Marine Protection, Research, and Sanctuaries Act (MPRSA) and the Clean Water Act (CWA). The MPRSA regulates the dumping of wastes in coastal and open-ocean waters, whereas the CWA has jurisdiction over pipeline discharges in all marine waters, wastes dumped in estuaries, and runoff. Many people consider that the passage and implementation of these two acts and their ensuing amendments established a statutory structure sufficient to protect the nation's waters from pollution. However, these provisions have not protected some estuaries and coastal waters from degradation.

Levenson, H.

1987-11-01

59

Sediment transport processes in estuaries: An introduction  

Science.gov (United States)

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.

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

1989-10-01

60

Metal behaviour in an estuary polluted by acid mine drainage: the role of particulate matter  

International Nuclear Information System (INIS)

[en] Particle sorption/de-sorption did not play a major role in metal dynamics in the water column of an estuary in Spain. - The concentrations of dissolved and suspended particulate Cd, Cu and Zn have been determined in water samples obtained during two axial transects of the Rio Tinto-Huelva Ria system in south-west Spain, which is severely impacted by acid mine drainage. Although the metal concentrations in both phases were elevated, dissolved metals were dominant and, in the upper estuary, constituted >99% of total metal in the water column. Dissolved metals behaved non-conservatively on each transect, with maximum concentrations in the low salinity region. There was no evidence of metal adsorption within the turbidity maximum zone, despite the high specific surface areas of resuspending particles. Measurements of electrophoretic mobility showed that the suspended particulate matter (SPM) had a positive surface charge in the salinity range 0-4, where the waters had a pH

2003-01-01

 
 
 
 
61

The spatial and temporal characteristics of harmful algal blooms in the southwest Bohai sea  

Science.gov (United States)

Harmful algal blooms (HABs) are harmful to coastal ecosystems, fisheries, the aquaculture industry, and even human health, thus they have received great attention worldwide. In this study, geostatistical tools in Geographic information system (GIS) were used to analyze HAB data collected over the last 11 years in the southwest Bohai Sea with the goal of detecting spatial and temporal characteristics of HAB events in this area. The seasonality, trend of HAB occurrences and the spatial pattern of HAB events were examined by time-series analysis and nearest neighbor analysis, respectively. The frequency of HAB occurrences was mapped using kernel density estimation, and the harm caused by HAB events was assessed and then categorized using a characteristic-based empirical model. The occurrences of HABs not only exhibited significant seasonality and a "single peak" trend in time but also were clustered in space. HABs had both a high frequency of occurrence and a high harm in the north Bohai Bay and the Yellow River estuary. In addition, HABs posed a high harm in the nearshore area near the city of Huanghua in Bohai Bay and the offshore area in the middle Bohai Bay; thus, HAB monitoring and/or management should be concentrated in these locales. Compared to previous descriptions, this research utilized a visualizable approach to more fully identify the scope, distribution, and characteristics of HAB occurrences in the southwest Bohai Sea, thus providing useful information to support the implementation of a monitoring and management program for HABs.

Wu, Zaixing; Yu, Zhiming; Song, Xiuxian; Yuan, Yongquan; Cao, Xihua; Liang, Yubo

2013-05-01

62

Estuary wader capacity following severe weather mortality  

Energy Technology Data Exchange (ETDEWEB)

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)

Clark, J.A.; Baillie, S.R.; Clark, N.A.; Langston, R.H.W.

1993-10-01

63

Estuary wader capacity following severe weather mortality  

International Nuclear Information System (INIS)

[en] 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)

1993-01-01

64

PCBs in phytoplankton in the Odra Estuary  

Directory of Open Access Journals (Sweden)

Full Text Available 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 species composition of the phytoplankton occurring in this area could also be very important as regards the sorption of PCBs.

Joanna Konat-Stepowicz; Gra?yna Kowalewska

2003-01-01

65

Ranking sediment samples from three Spanish estuaries in relation to its toxicity for two benthic species: the microalga Cylindrotheca closterium and the copepod Tisbe battagliai.  

UK PubMed Central (United Kingdom)

The present study assesses the sediment toxicity levels of three Spanish estuaries, as well as the suitability of two microorganisms, the benthic microalga Cylindrotheca closterium and the harpacticoid copepod Tisbe battagliai, as test organisms in whole-sediment toxicity assays. The sensitivity of both species to potentially polluted sediments was compared. Three sites at the southwest of the Iberian Peninsula were chosen: the Ría of Huelva, the Guadalquivir Estuary, and the Bay of Algeciras. Inhibition data were based on growth for C. closterium and fecundity for T. battagliai. No toxicity was recorded for the microalga in the Guadalquivir Estuary and the Bay of Algeciras. However, for T. battagliai, inhibition of fecundity was approximately 50% in those zones, indicating higher sensitivity. Samples from stations in the Ría of Huelva were the most toxic of all those assayed; inhibition values higher than 90% were obtained for both organisms. The highest values for total metal concentrations such as arsenic (As), cadmium (Cd), copper (Cu), iron (Fe), lead (Pb), tin (Sn), and zinc (Zn) were found in the Ría of Huelva, which can be classified as severely impacted. The Guadalquivir Estuary and the Bay of Algeciras can be considered moderately impacted. In general, both methodologies are suitable for application in ecotoxicological studies.

Araújo CV; Diz FR; Tornero V; Lubián LM; Blasco J; Moreno-Garrido I

2010-02-01

66

Fisheries oceanography of the southeast bering sea: Relationships of growth, dispersion and mortality of sand lance larvae to environmental conditions in the port moller estuary. Final report  

Energy Technology Data Exchange (ETDEWEB)

The objective of the study was to describe the early life history of Pacific sand lance, Ammodytes hexapterus, in the southeastern Bering Sea so as to assess the potential impact of oil and gas development in the area of forage fishes. A fisheries oceanography program in the Port Moller estuary from April to July, 1990, collected 473 samples of ichthyoplankton. Analysis of these samples showed that three waves of adult Pacific sand lance entered the Port Moller estuary from mid-January to late May, 1990, and laid their eggs on sand banks in the shallow, well-mixed outer portion of the estuary. After an incubation period of 41 to 63 days, newly-hatched larvae moved at an average speed of about .3 km/day towards a fjord-like basin in upper Herendeen Bay about 20 km southwest of the center of hatch. The basin develops a spring-summer zooplankton community with greater biomass than any other part of the estuary. The fate of the stock depends on maintenance of undisturbed spawning beds and a productive larval rearing area.

McGurk, M.D.; Warburton, H.D.

1992-05-01

67

Trace metals in the Westerschelde Estuary: a case-study of a polluted, partially anoxic estuary  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Oceans and lakes are characterised by great residence times and can thus be considered to be in a state of equilibrium or quasi-equilibrium. Estuaries, by contrast, which constitute the interface between freshwater and marine ecosystems, are biogeo...

68

SOUTHWEST REGIONAL PARTNERSHIP ON CARBON SEQUESTRATION  

Energy Technology Data Exchange (ETDEWEB)

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.

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

69

Mouth Bar Formation in Yangtze River Estuary  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The periodic shifting of the bifurcation point of the North Channel and South Channel of the Yangtze river is very important in the estuary. The North Channel is bifurcated from the South Branch by cutting a channel through the submerged sandbanks. Once a bifurcation channel is formed, the differen...

Wei, C.

70

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)

1993-01-01

71

Stable pollutants in the Scheldt estuary  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Samples were taken at several dumping and dredging sites, situated in the Schelde estuary, between Antwerp (80 km from the mouth) and Vlissingen (at the mouth). Besides analysis of different metals (Al, Pb, Cd, Cr) other parameters such as organic carbon content (POC), Ash-weight (AW), granulometric...

Monteny, F.; Leermakers, M.; Vandenhoudt, A.; Baeyens, W.F.J.

72

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

Science.gov (United States)

...Revision of the Estuary Habitat Restoration Strategy Prepared by the Estuary Habitat Restoration...of the ``Estuary Habitat Restoration Strategy.'' DATES: Comments and information...comments to Estuary Habitat Restoration Strategy, NOAA Fisheries Service, 1315...

2010-11-15

73

A chemical survey of the Mississippi estuary  

Energy Technology Data Exchange (ETDEWEB)

A snap shot survey of the Mississippi estuary was made during a period of low river discharge, when the estuarine mixing zone was within the deltaic channels. Concentrations of H{sup +}, Ca{sup 2+}, inorganic phosphorus and inorganic carbon suggest that the waters of the river and the low salinity (<5%) portion of the estuary are near saturation with respect to calcite and sedimentary calcium phosphate. An input of oxidized nitrogen species and N{sub 2}O was observed in the estuary between O and 4{per thousand} salinity. The concentrations of dissolved NH{sub 4}{sup +} and O{sub 2}, over most of the estuary, appeared to be influenced by decomposition of terrestrial organic matter in bottom sediments. The estuarine bottom also appears to be a source of CH{sub 4} which has been suggested to originate from petroleum shipping and refining operations. Estuarine mixing with offshore Gulf waters was the dominant influence on distributions of dissolved species over most of the estuary (i.e., from salinities > 5%). The phytoplankton abundance (measured as chlorophyll a) increased as the depth of the mixed layer decreased in a manner consistent with the expected for a light-limited ecosystem. Fluxes of NO{sub 3}{sup {minus}} + NO{sub 2}{sup {minus}} and soluble inorganic phosphorus to the Gulf of Mexico were estimated to be 3.4 {plus minus} 0.2 {times} 10{sup 3} g N s{sup {minus}1} and 1.9 {plus minus} g P s{sup {minus}1}, respectively, at the time of this study.

Fox, L.E.; Lipschultz, R.; Kerkhof, L.; Wofsy, S.C. (Harvard Univ., Cambridge, MA (USA))

1987-03-01

74

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

Energy Technology Data Exchange (ETDEWEB)

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.

Windom, H.L.

1991-12-31

75

Southwest residential experiment station: the first year  

Energy Technology Data Exchange (ETDEWEB)

The Southwest Residential Experiment Station (SW RES) is part of the Department of Energy's National Photovoltaic Program aimed at the residential applications sector. The SW RES is currently erecting 8 of a planned 15 prototype residence-like photovoltaic systems. The first year's history and the current status are presented. Other current and planned hardware systems are discussed.

Schaefer, J.; Zwibel, H.

1981-01-01

76

Southwest Energy Innovation Forum: Summary Report  

Science.gov (United States)

The Ewing Marion Kauffman Foundation, Arizona State University (ASU), and U.S. Department of Energy's Advanced Research Projects Agency-Energy (ARPA-E) co-convened a conference on Energy Innovation in the Southwest region of the United States that included participation by entrepreneurs, state government officials, representatives of academia,…

Ewing Marion Kauffman Foundation, 2010

2010-01-01

77

Benthic primary production in the Columbia River Estuary. Final report  

Energy Technology Data Exchange (ETDEWEB)

The general objective of the research associated with the Benthic Primary Production Work Unit of Columbia River Estuary Development Program was to determine mechanisms that control the production dynamics and species composition of benthic plant assemblages in the Columbia River Estuary. In particular, the work was concerned with effects of selected physical variables on structural and functional attributes of micro- and macro- vegetation, and on the productivity and biomass of benthic autotrophs on the tidal flats of the estuary.

McIntire, C.D.; Amspoker, M.C.

1984-02-01

78

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

Directory of Open Access Journals (Sweden)

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

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

2013-01-01

79

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

Directory of Open Access Journals (Sweden)

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

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

2012-01-01

80

[Study on nanoparticles in Yangtze Estuary].  

UK PubMed Central (United Kingdom)

Filtration and cross-flow ultrafiltration (CFUF) was applied for the effective separation of NPs in the Yangtze Estuary. The physiochemical properties of NP were characterized, and their relationships with environmental factors were further studied in the present study. The results show that NP size in Yangtze Estuary ranged from 69.5 to 263.5 nm with the average value of 157.3 nm and Zeta-potential values ranged from -40.1 mV to 196.0 mV. NOC concentrations ranged from 0.3 mg/L to 1.5 mg/L and the average value was 0.7 mg/L. NOC account for 5.1% to 30.5% of DOC, with an average of 16.7%. The binding capacity of metals with NP in the Yangtze River Estuary was in the order of Zn > Cu > total Cr > Co > Ni > Mn > Fe > Li > Al > B > K > Ba > Sr > Mg > Ca > Na, which reveals that terrigenous input may be the main source of NOC in the Yangtze River. The binding capacity of NP with trace metal is generally higher than the conventional metallic element. There was no significant correlation between NP size and salinity, DOC, NOC, SPM and Zeta-potential, respectively. Compared to NOC and UOC, better correlation was investigated between DOC, salinity and NP bound trace metals.

Fu JL; Yang Y; Peng H; Zhou LM; Hou LJ; Liu M

2011-07-01

 
 
 
 
81

Southwest Regional Partnership on Carbon Sequestration  

Energy Technology Data Exchange (ETDEWEB)

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.

Brian McPherson

2006-03-31

82

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

International Nuclear Information System (INIS)

[en] 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

2001-01-01

83

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

Energy Technology Data Exchange (ETDEWEB)

A reconnaissance study has been made on the distribution of {sup 238}U, {sup 234}U, {sup 232}Th and {sup 230}Th 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 {sup 238}U/Al and {sup 232}Th/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 {sup 232}Th 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 {mu}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 26.3x10{sup 6} g/yr to the Arabian Sea which is about 2% of the flux from the Himalayan rivers to the Bay of Bengal.

Balakrishna, K.; Shankar, R. E-mail: rshankar_1@yahoo.com; Sarin, M.M.; Manjunatha, B.R

2001-06-01

84

Mobility of contaminants in relation to dredging operations in a mesotidal estuary (Tagus Estuary, Portugal)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

During the construction of a New Bridge over the Tagus estuary 2.5 million tons of sediments were dredged, part of this quantity being contaminated material. The extension and intensity of the water turbidity associated with dredging operating varied with the tidal conditions but the resuspended mat...

Vale, Carlos; Ferreira, Ana; Micaelo, Cristina; Caetano, Miguel; Pereira, Eduarda; Madureira, Maria; Ramalhosa, Elsa

85

Metal behaviour in an estuary polluted by acid mine drainage: the role of particulate matter  

Energy Technology Data Exchange (ETDEWEB)

Particle sorption/de-sorption did not play a major role in metal dynamics in the water column of an estuary in Spain. - The concentrations of dissolved and suspended particulate Cd, Cu and Zn have been determined in water samples obtained during two axial transects of the Rio Tinto-Huelva Ria system in south-west Spain, which is severely impacted by acid mine drainage. Although the metal concentrations in both phases were elevated, dissolved metals were dominant and, in the upper estuary, constituted >99% of total metal in the water column. Dissolved metals behaved non-conservatively on each transect, with maximum concentrations in the low salinity region. There was no evidence of metal adsorption within the turbidity maximum zone, despite the high specific surface areas of resuspending particles. Measurements of electrophoretic mobility showed that the suspended particulate matter (SPM) had a positive surface charge in the salinity range 0-4, where the waters had a pH<3. Desorption experiments were carried out in which SPM from the turbidity maximum zone was resuspended in coastal seawater. The desorption of the metals was monitored for 24 h, using anodic stripping voltammetry (ASV) to detect the variation in total dissolved Cd, Cu and Zn and the species of Cu and Zn. Total dissolved Cd concentrations doubled during the incubation period, whereas the concentration of total dissolved Cu declined and that of Zn remained rather constant. The ASV-labile fraction of dissolved Cu and Zn showed an initial sharp release followed by a slower uptake. However, desorption was shown to be a minor source of dissolved metals and made little contribution to the non-conservative behaviour in the low salinity zone. The results are used to predict the effects of acid mine drainage on estuarine ecology.

Achterberg, E.P.; Herzl, V.M.C.; Braungardt, C.B.; Millward, G.E

2003-02-01

86

Polycyclic aromatic hydrocarbons in coastal sediments of southwest Taiwan: An appraisal of diagnostic ratios in source recognition  

Energy Technology Data Exchange (ETDEWEB)

Fifty-seven surface sediment samples were collected from the coast of southwest Taiwan and analyzed for polycyclic aromatic hydrocarbons (PAHs). Concentrations of total PAHs (28 PAH compounds) ranged from 15 to 907 ng g{sup -1} dry weight. Diagnostic ratios showed that PAHs in the sediments of the Gaoping estuary were predominantly of petroleum origin, whereas sediments from the Kaohsiung coast contained principally combustion-derived PAHs. Principal component analysis indicated that emissions from automobiles and coal burning were the main sources of combustion-derived PAHs. The relatively high ratios of perylene/penta-aromatic PAH isomers in sediments from the Tainan coast and some off-shore stations on the Kaohsiung coast suggest a significant diagenetic PAH contribution. The study shows that certain diagnostic ratios are useful and sensitive in delineating the distribution of PAHs from specific sources in southwest Taiwan. The phenanthrene/anthracene ratio is a better indicator than the methylphenanthrenes/phenanthrene ratio for tracing petrogenic PAHs, and the benzo(a)anthracene/chrysene and indeno(1,2,3-c,d)pyrene/benzo(g,h,i)perylene ratios are more specific than the benzo(a)pyrene/benzo(e)pyrene and benzo(b)fluoranthcene/benzo(k)fluoranthcene ratios in distinguishing PAHs from various pyrogenic sources.

Jiang, J.J.; Lee, C.L.; Fang, M.D.; Liu, J.T. [National Sun Yat Sen University, Kaohsiung (Taiwan)

2009-05-15

87

Mercury distribution in Douro estuary (Portugal)  

International Nuclear Information System (INIS)

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

2005-01-01

88

Mercury distribution in Douro estuary (Portugal)  

Energy Technology Data Exchange (ETDEWEB)

Determinations of dissolved reactive and total dissolved mercury, particulate and sedimentary mercury, dissolved organic carbon (DOC), particulate organic carbon (POC) and suspended particulate matter (SPM) have been made in the estuary of river Douro, in northern Portugal. The estuary was stratified by salinity along most of its length, it had low concentrations of SPM, typically <20 mg dm{sup -3}, and concentrations of DOC in the range <1.0-1.8 mg dm{sup -3}. The surface waters had a maximum dissolved concentration of reactive mercury of about 10 ng dm{sup -3}, whereas for the more saline bottom waters it was about 65 ng dm{sup -3}. The surface waters had maximum concentrations of total suspended particulate mercury of {approx}7 {mu}g g{sup -1} and the bottom waters were always <1 {mu}g g{sup -1}. Concentrations of mercury in sediments was low and in the range from 0.06 to 0.18 {mu}g g{sup -1}. The transport of mercury in surface waters was mainly associated with organic-rich particulate matter, while in bottom waters the dissolved phase transport of mercury is more important. Lower particulate organic matter, formation of chlorocomplexes in more saline waters and eventually the presence of colloids appear to explain the difference of mercury partitioning in Douro estuarine waters.

Ramalhosa, E. [Department of Chemistry, University of Aveiro, 3810-193 Aveiro (Portugal); Pereira, E. [Department of Chemistry, University of Aveiro, 3810-193 Aveiro (Portugal)]. E-mail: eduper@dq.ua.pt; Vale, C. [National Institute for Agronomy and Fishery Research, IPIMAR, Avenida Brasilia, 1449-006 Lisboa (Portugal); Valega, M. [Department of Chemistry, University of Aveiro, 3810-193 Aveiro (Portugal); Monterroso, P. [Department of Chemistry, University of Aveiro, 3810-193 Aveiro (Portugal); Duarte, A.C. [Department of Chemistry, University of Aveiro, 3810-193 Aveiro (Portugal)

2005-11-15

89

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

Directory of Open Access Journals (Sweden)

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.

Vidal J.; Tejedor B.

2005-01-01

90

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

International Nuclear Information System (INIS)

[en] 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)

1990-01-01

91

Obelionic cranial deformation in the Puebloan Southwest.  

UK PubMed Central (United Kingdom)

As a form of cranial deformation, obelionic flattening is rare. Originally named and described by Stewart (J Wash Acad Sci 29 (1939) 460-465), based on a small sample from Florida, it has been little noted since. Previously [Nelson and Madimenos, Paper presented at the Paleopathology Association annual meeting (2007)], we reported the discovery of two individuals from the Pueblo III Gallina site of Cañada Simon I who exhibit flattening of this type. Although technically undescribed in the Southwest before now, there are tantalizing clues in the literature that it occurred in low frequencies throughout the Ancestral Pueblo world. To determine whether the obelionic flattening found at Cañada Simon I was isolated or an indication of a more widespread phenomenon, we undertook a survey of crania from other Gallina sites, Chaco Canyon, and the literature (type of deformation can be determined on lateral photographs of crania properly positioned along the Frankfort Horizontal). We examined 146 crania (78 firsthand) of which seven exhibit obelionic flattening. Our results indicate that obelionic flattening should be added to the suite of cranial deformations that occur in the Southwest. Here, we propose parameters by which obelionic flattening can be described and differentiated from the more common lambdoidal and occipital forms and suggest that the three types of flattening form a continuum of cradleboard induced deformation, although the exact mechanism for obelionic flattening remains elusive. Am J Phys Anthropol, 2010. © 2010 Wiley-Liss, Inc.

Nelson GC; Madimenos FC

2010-11-01

92

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

Directory of Open Access Journals (Sweden)

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.

Geddada Mohan NARASIMHA RAO; Prayaga Murty PRAGADA

2010-01-01

93

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

Energy Technology Data Exchange (ETDEWEB)

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)

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

94

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

International Nuclear Information System (INIS)

[en] 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)

2004-01-01

95

Statistical Summary: EMAP-Estuaries Virginian Province, 1990 to 1993.  

Science.gov (United States)

Monitoring of indicators of the ecological condition of bays, tidal rivers, and estuaries within the Virginian Biogeographic Province (Cape Cod, Massachusetts to Cape Henry, Virginia) was conducted annually by the U.S. EPA's Environmental Monitoring and A...

C. J. Strobel D. R. Reifsteck E. A. Petrocelli H. W. Buffum S. J. Benyi

1995-01-01

96

SAN JUAN BAY ESTUARY PROGRAM IMPLEMENTATION REVIEW ATTACHMENTS  

Science.gov (United States)

A compilation of attachments referenced in the San Juan Bay Estuary Program Implementation Review (2004). Materials include, entity reports, water and sediment quality action plans, progress reports, correspondence with local municipalities and Puerto Rican governmental agencies,...

97

Environmental forcing on jellyfish communities in a small temperate estuary.  

Science.gov (United States)

The impact of biological, hydrodynamic and large scale climatic variables on the jellyfish community of Mondego estuary was evaluated from 2003 to 2010. Plankton samples were collected at the downstream part of the estuary. Siphonophora Muggiaea atlantica and Diphyes spp. were the main jellyfish species. Jellyfish density was generally higher in summer and since 2005 densities had increased. Summer community analysis pointed out Acartia clausi, estuarine temperature and salinity as the main driven forces for the assemblage's structure. Also, Chl a, estuarine salinity, runoff and SST were identified as the major environmental factors influencing the siphonophores summer interannual variability. Temperature influenced directly and indirectly the community and fluctuation of jellyfish blooms in the Mondego estuary. This study represents a contribution to a better knowledge of the gelatinous plankton communities in small temperate estuaries. PMID:22770533

Primo, Ana Lígia; Marques, Sónia C; Falcão, Joana; Crespo, Daniel; Pardal, Miguel A; Azeiteiro, Ulisses M

2012-06-23

98

Evaluating Causes of Ecological Impairments in the Estuaries of Ukraine  

Science.gov (United States)

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

99

Environmental forcing on jellyfish communities in a small temperate estuary.  

UK PubMed Central (United Kingdom)

The impact of biological, hydrodynamic and large scale climatic variables on the jellyfish community of Mondego estuary was evaluated from 2003 to 2010. Plankton samples were collected at the downstream part of the estuary. Siphonophora Muggiaea atlantica and Diphyes spp. were the main jellyfish species. Jellyfish density was generally higher in summer and since 2005 densities had increased. Summer community analysis pointed out Acartia clausi, estuarine temperature and salinity as the main driven forces for the assemblage's structure. Also, Chl a, estuarine salinity, runoff and SST were identified as the major environmental factors influencing the siphonophores summer interannual variability. Temperature influenced directly and indirectly the community and fluctuation of jellyfish blooms in the Mondego estuary. This study represents a contribution to a better knowledge of the gelatinous plankton communities in small temperate estuaries.

Primo AL; Marques SC; Falcão J; Crespo D; Pardal MA; Azeiteiro UM

2012-08-01

100

Heavy metals in fucus vesiculosus in the Humber Estuary  

Energy Technology Data Exchange (ETDEWEB)

Samples of brown seaweed Fucus vesiculosus from the south bank of the Humber Estuary have been analyzed for Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn. Distribution of Cd, Cu, Ni and Zn along the estuary are represented graphically. Cd and Ni are conservative, but the plots for Cu and Zn suggest inputs of these metals in the lower estuary. Elevated Fe levels are considered to result from contamination by suspended sediment, but concentrations at one site in the lower estuary are indicative of an input of soluble iron. All Pb and Cr results can be accounted for entirely by particulate contamination. Data from the Humber is compared with figures available in the literature. Concentrations of Cd, Cu and Zn are much greater than background levels and compared with contaminated conditions elsewhere, whilst Ni concentrations include the highest values reported for any location. It is concluded that Fucus vesiculosus in the Humber exhibits substantially elevated levels of heavy metals.

Barnett, B.E.; Ashcroft, C.R.

1985-01-01

 
 
 
 
101

Two-dimensional hydrodynamic model of St. Lucie Estuary  

Energy Technology Data Exchange (ETDEWEB)

A two-dimensional hydrodynamic model of St. Lucie Estuary was developed to assess the impact of drainage canal discharge and storm water runoff. Water surface elevation, two-dimensional velocity field and salinity are collected during 1998--1998 ENSO episode. The data sets cover an eight months period that includes both wet ad dry weather conditions. The model has been applied to St. Lucie Estuary salinity study. It will also provide flow fields to a water quality model.

Hu, G.G.

1999-07-01

102

Frequency of twinning in southwest Nigeria  

Directory of Open Access Journals (Sweden)

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

Akinboro A; Azeez M; Bakare A

2008-01-01

103

Yeast community survey in the Tagus estuary.  

Science.gov (United States)

The yeast community in the waters of the Tagus estuary, Portugal, was followed for over a year in order to assess its dynamics. Yeast occurrence and incidence were measured and this information was related to relevant environmental data. Yeast occurrence did not seem to depend upon tides, but river discharge had a dramatic impact both on the density and diversity of the community. The occurrence of some yeasts was partially correlated with faecal pollution indicators. Yeast isolates were characterized by microsatellite primed PCR (MSP-PCR) fingerprinting and rRNA gene sequencing. The principal species found were Candida catenulata, C. intermedia, C. parapsilosis, Clavispora lusitaniae, Debaryomyces hansenii, Pichia guilliermondii, Rhodotorula mucilaginosa and Rhodosporidium diobovatum. The incidence of these species was evaluated against the environmental context of the samples and the current knowledge about the substrates from which they are usually isolated. PMID:16329949

de Almeida, João M G C F

2005-07-01

104

Monitoring Rehabilitation in Temperate North American Estuaries  

Energy Technology Data Exchange (ETDEWEB)

In this chapter, we propose that monitoring rehabilitation in estuarine ecosystems by necessity requires quantifying relationships between dynamic estuarine processes and sensitive indicators of ecosystem function. While we do discuss temperate systems in general, emphasis is placed on anadromous salmon habitats in the Pacific Northwest because anadromous fishes are such a major focus of rehabilitation efforts, and present some of the greater challenges in linking function of one segment of their life history to conditions in a specific habitat. We begin with a basic overview of the ecological and socioeconomic significance of, as well as anthropogenic effects on, estuaries. Next, we briefly summarize the various kinds of estuarine rehabilitation historically practiced in temperate regions, and review estuarine rehabilitation monitoring design and methods, highlighting the unique challenges involved in monitoring estuarine systems. We then close with a summary and conclusions.

Rice, Casimir A.; Hood, W Gregory; Tear, Lucinda M.; Simenstad, Charles; Williams, Gregory D.; Johnson, L. L.; Feist, B. E.; Roni, P.

2005-02-01

105

Conservation of Thane Creek and Ulhas River Estuary, India.  

Science.gov (United States)

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

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

2009-07-01

106

Conservation of Thane Creek and Ulhas River Estuary, India.  

UK PubMed Central (United Kingdom)

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

Nikam VS; Kumar A; Lalla K; Gupta K

2009-07-01

107

Aging and sediment characteristics of northern Gulf of Mexico estuaries  

Energy Technology Data Exchange (ETDEWEB)

Eight major estuarine systems present along the northern margin of the Gulf of Mexico serve as primary depositional basins for all rivers draining into the gulf from central Louisiana eastward to the Florida peninsula. These estuaries consist of Apalachicola Bay, St. Andrews Bay, Choctawhatchee Bay, Pensacola Bay, Perdido Bay, Mobile Bay, Mississippi sound, and Lake Pontchartrainn. Because each receives sediment from a different river system (or systems), each estuary is characterized by sediments that are both physically and mineralogically distinct. Estuaries in the eastern Gulf, for example, possess a clay mineral suite dominated by kaolinite (derived from deeply weathered piedmont rocks), whereas those from the western Gulf are rich in smectite and mixed layer clays (reflecting a Western Interior or provenance from Paleozoic or older coastal plain sources). Similarly, weathering of rocks in the southern piedmont has provided eastern Gulf estuarine sediments with a suite of largely metamorphic rock-derived heavy minerals, whereas those in the western Gulf contain a mixed suite of both igneous- and metamorphic-derived minerals. Equally distinctive, however, are the textures of the bottom sediments themselves for each estuary when plotted on standard sand-silt-clay ternary diagrams. The relative percentages of these components are uniquely different for most of the estuaries and reflect both natural and anthropogenic conditions that exist in the watershed areas that drain into each estuary.

Isphording, W.C. (Univ. of South Alabama, Mobile (USA)); Imsand, F.D. (Army Corps of Engineers, Mobile, AL (USA)); Flowers, G.C. (Tulane Univ., New Orleans, LA (USA))

1989-09-01

108

Insect fauna visiting carrion in Southwest Virginia.  

Science.gov (United States)

Successional patterns of insect fauna on pig carcasses were studied in southwest Virginia. The objective was to identify and qualitatively assess the major taxa of forensic importance in this region. Studies were conducted in spring and summer 2001 and 2002, and fall 2002. Over 50 taxa were collected and identified. Phormia regina was the dominant fly species in the spring (>90%) and co-dominant with Phaenicia coeruleiviridis in the summer. Phaenicia sericata, Lucilia illustris, and Calliphora spp. were collected in spring and summer, but less frequently. Eleven species of Sarcophagidae also were collected with Sarcophaga utilis and Helicobia rapax the most common. In the fall, the dominant fly species were Calliphora vomitoria, L. illustris, and P. coeruleiviridis. The primary beetle species collected in spring and summer included three Staphylinidae (Creophilis maxillosus, Platydracus maculosus, and Aleochara lata) and three Silphidae (Oiceoptoma noveboracense, Necrodes surinamensis, and Necrophila americana). No beetles were collected in the fall. PMID:15837010

Tabor, Kimberly L; Fell, Richard D; Brewster, Carlyle C

2005-05-28

109

Insect fauna visiting carrion in Southwest Virginia.  

UK PubMed Central (United Kingdom)

Successional patterns of insect fauna on pig carcasses were studied in southwest Virginia. The objective was to identify and qualitatively assess the major taxa of forensic importance in this region. Studies were conducted in spring and summer 2001 and 2002, and fall 2002. Over 50 taxa were collected and identified. Phormia regina was the dominant fly species in the spring (>90%) and co-dominant with Phaenicia coeruleiviridis in the summer. Phaenicia sericata, Lucilia illustris, and Calliphora spp. were collected in spring and summer, but less frequently. Eleven species of Sarcophagidae also were collected with Sarcophaga utilis and Helicobia rapax the most common. In the fall, the dominant fly species were Calliphora vomitoria, L. illustris, and P. coeruleiviridis. The primary beetle species collected in spring and summer included three Staphylinidae (Creophilis maxillosus, Platydracus maculosus, and Aleochara lata) and three Silphidae (Oiceoptoma noveboracense, Necrodes surinamensis, and Necrophila americana). No beetles were collected in the fall.

Tabor KL; Fell RD; Brewster CC

2005-05-01

110

Southwest Regional Partnership on Carbon Sequestration  

Energy Technology Data Exchange (ETDEWEB)

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

Brian McPherson

2006-04-01

111

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

International Nuclear Information System (INIS)

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

1994-01-01

112

Contribution of N2O emissions to the atmosphere from Indian monsoonal estuaries  

Directory of Open Access Journals (Sweden)

Full Text Available Estuaries are known to contribute a significant amount of nitrous oxide (N2O) to the atmosphere; however, the contribution from the Indian estuaries is unknown. We made an attempt to estimate emissions of N2O from the Indian estuaries by collecting samples from 28 major and minor estuaries along the Indian coast during the wet and dry periods. The N2O was mostly saturated in all measured Indian estuaries during the study period (72–631%), with exceptionally high saturation in the Ponniyaar estuary (5902%) during the wet period. The N2O saturation displayed a strong relation with dissolved inorganic nitrogen (DIN; nitrate +nitrite and ammonium), ammonium and dissolved oxygen saturation, suggesting that nitrification is the major source of N2O in the Indian estuaries. The negative relation between salinity and N2O saturation suggests inner estuaries are a strong source compared to outer estuaries. The annual mean N2O saturation (204±137%) and fluxes (1.3 µmol N2O m?2 d?1) in the Indian estuaries were significantly less than European estuaries (271% and ~2.7 µmol N2O m?2 d?1, respectively). The estimation of flux of N2O from the European estuaries was also biased due to the inclusion of an exceptionally high supersaturation value from a small UK estuary, Colne (2645%). However, low N2O saturation and fluxes in the Indian estuaries were related to mean low concentration of DIN that led to low nitrification rates compared to world estuaries. Despite India ranking second in artificial fertilizers use, high flushing rates during the wet period reduce residence time leading to less modification within the estuary.

Gijjapu Durga Rao; Vedula V. S. S. Sarma

2013-01-01

113

Investigations of Manganese Nodules from Southwest Indian Ocean.  

Science.gov (United States)

Background information is presented on sediments associated with some manganese nodules in the southwest Indian Ocean. Manganese nodules from four different areas -- Crozet Basin, Agulhas Plateau, Madagascar Ridge and Mascerent Basin were selected. The no...

K. Venkatarathnam C. E. Nehru

1973-01-01

114

What Price Energy? Hazards of Uranium Mining in the Southwest.  

Science.gov (United States)

This article describes the hazards, sickness, death and destruction caused by uranium mining/nuclear energy development in the Southwest focusing on the experiences of several Indian uranium mines. (RTS)

Barry, Tom

1979-01-01

115

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

Science.gov (United States)

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.

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

2013-05-01

116

Life in an extreme environment: phytoplankton blooms in the upper Scheldt estuary  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Being extremely turbid environments characterised by short residence times and rapid changes in salinity, the upper reaches of estuaries comprise an extreme environment for phytoplankton to live and grow in. Nevertheless, in many estuaries including the Schelde estuary, these reaches often support d...

Kromkamp, J.

117

A Simple Model of Nitrogen Concentration, Throughput, and Denitrification in Estuaries  

Science.gov (United States)

The Estuary Nitrogen Model (ENM) is a mass balance model that includes calculation of nitrogen losses within bays and estuaries using system flushing time. The model has been used to demonstrate the dependence of throughput and denitrification of nitrogen in bays and estuaries on...

118

Fluxes and major transport routes of arsenic in the Scheldt estuary  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The estuary of the Scheldt was monitored for As during seven seasonally spread sampling campaigns. The resulting data indicated that As did not behave conservatively in the estuary; an important mobilisation of As was observed from the river up to halfway the estuary. Both input flux (from river to ...

De Gieter, M.; Elskens, M.; Baeyens, W.

119

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

Directory of Open Access Journals (Sweden)

Full Text Available ???????????????????????????????????????????????–????????????????????????????????????????????????????????????????????????13???????????????31????X??????(XRF)??????(AAS)???????????(ICP-MS)?????????????????????????????????????Pb?????????????Zn????????Ni??????????As???????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????Accompanied by urbanization and industrialization process in Tangshancoastal zone, the heavy metal pollution increased. The representative parts, such as Jianhe Estuary, the Luannan Zuidong Industrial Zone, Caofeidian Industrial Zone, the Qinglonghe Estuary, Caofeidian Wetlands, the Laoting Qianshui Bay, and Jingtang Port in Bohai West Bank, were chosen, selecting the 13 sampling sites, 31 surface sediment samples. X-ray fluorescence spectrometry (XRF), atomic absorption spectrometry (AAS) and inductively coupled plasma mass spectrometry (ICP-MS) were used to test the samples of heavy metals concentrations. Studies have shown that except the Caofeidian Industrial Zone, Pb contents in the other sampling points are more than the background value. Zn exceeded in the two sampling sites and Ni in one sample point. As exceeded in sampling points of Caofeidian outfall. The reason for this phenomenon may be closely related to the layout of the surrounding industry, and unreasonable sewage of agricultural production. For the intertidal zone in the study area, potential ecological risk of heavy metal content prove that the overall heavy metal content in surface sediments belongs to the minor ecological harm, but it should be strengthened that the observation and monitoring of key areas, and pay close attention to the accumulation and the harmful process.

???; ???; ??; ???; ??; ???

2012-01-01

120

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

International Nuclear Information System (INIS)

[en] 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

1991-01-01

 
 
 
 
121

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

Energy Technology Data Exchange (ETDEWEB)

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.

Sylves, R.T.

1991-01-01

122

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)

1990-01-01

123

Methane in surface waters of Oregon estuaries and rivers  

Energy Technology Data Exchange (ETDEWEB)

Methane concentrations in surface waters of Oregon rivers and estuaries were measured over a four-year period. Geographic variations in riverine CH{sub 4} were observed. Results from undisturbed forest streams indicate that rivers can contain high natural levels of CH{sub 4} not attributable to pollution. Lateral diffusion and runoff from saturated forest and fertilized agricultural soils may be important in determining methane levels in rivers. Methane concentrations in well-flushed estuaries appear to be controlled mainly by mixing between high CH{sub 4}-containing river water and low CH{sub 4}-containing seawater endmembers. Rivers and estuaries were found to be sources of methane to the atmosphere. Calculated daily fluxes to the atmosphere ranged from 1.2 to 71 mg CH{sub 4} sq m for rivers and from 0.04 to 21 mg CH{sub 4} sq m for estuarine samples. 24 refs., 4 figs., 3 tabs.

de Angelis, M.A.; Lilley, M.D. (Washington Univ., Seattle (USA))

1987-05-01

124

Does boat traffic cause displacement of fish in estuaries?  

UK PubMed Central (United Kingdom)

Estuaries are increasingly under threat from a variety of human impacts. Recreational and commercial boat traffic in urban areas may represent a significant disturbance to fish populations and have particularly adverse effects in spatially restricted systems such as estuaries. We examined the effects of passing boats on the abundance of different sized fish within the main navigation channel of an estuary using high resolution sonar (DIDSON). Both the smallest (100-300mm) and largest (>501mm) size classes had no change in their abundance following the passage of boats. However, a decrease in abundance of mid-sized fish (301-500mm) occurred following the passage of boats. This displacement may be attributed to a number of factors including noise, bubbles and the rapidly approaching object of the boat itself. In highly urbanised estuarine systems, regular displacement by boat traffic has the potential to have major negative population level effects on fish assemblages.

Becker A; Whitfield AK; Cowley PD; Järnegren J; Næsje TF

2013-08-01

125

Butyltin compounds in sediments of the Bahia Blanca estuary, Argentina.  

UK PubMed Central (United Kingdom)

Systematic measurements of both Tributyltin (TBT) and Dibutyltin (DBT) in sediments along different locations in the inner zone of Bahía Blanca estuary were done. Two samples were taken near the main dry dock facility, at Puerto Belgrano naval base, in Argentina. TBT concentrations from non-detected to 170.3 ng Sn g(-1) were measured in the inner region of the estuary, and higher one of 3,288 ng Sn g(-1) near the dry dock at Puerto Belgrano. DBT values ranging between non-detected and 75.2 ng Sn g(-1) were obtained along the principal channel, but extreme concentration of 1,645 ng Sn g(-1) was measured at Puerto Belgrano. These values show that this estuary is affected by organotin pollution, mainly in areas of heavy shipyard activities.

Delucchi F; Tombesi NB; Freije RH; Marcovecchio JE

2007-09-01

126

The recreational value of river inflows into South African estuaries  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english 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, river 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 re (more) duced. 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.

Hosking, Stephen

2011-01-01

127

Foraminifera of Arasalar estuary, Karaikkal, south east coast of India.  

UK PubMed Central (United Kingdom)

A total of fifty-two foraminiferal species belonging to 23 genera and 16 families were recorded from Arasalar estuary for a period of one year (July 2000 to June 2001). Miliammina fusca, Quinqueloculina agglutinans, Q. seminula, Cibicides refulgens, Ammonia beccarii, Elphidium clavatum, E. incertum are the abundant species. Due to marine water influence the number and populations of foraminifera was high during summer and premonsoon seasons. The various ecological parameters such as temperature, salinity, pH, dissolved oxygen of bottom water and sediment organic matter were studied. Salinity is the key factor for governing distribution and abundance of foraminifera of this estuary.

Bragadeeswaran S; Rajasegar M

2004-01-01

128

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

2008-02-05

129

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

UK PubMed Central (United Kingdom)

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

Silva MA; Eça GF; Santos DF; Guimarães AG; Lima MC; de Souza MF

2013-07-01

130

The recovery of oyster (Saccostrea glomerata) populations in Sydney estuary (Australia).  

UK PubMed Central (United Kingdom)

The current work documented a significant and widespread increase in the abundance of the Sydney rock oyster Saccostrea glomerata, in Sydney estuary (Australia) by undertaking surveys of oyster density in the estuary in 1989 and annually from 1994 to 2006. Oyster density at six control sites located in nearby National Parks unaffected by boating and stormwater discharges were compared to 17 study sites widely distributed within Sydney estuary. No oyster populations were evident in Sydney estuary in 1989; however, by 1994 oysters had colonised areas of the lower and central estuary and by 2002 densities were statistically similar to control sites. The timing of estuary-wide increases in oyster abundance suggests that the partial banning of tributyltin in 1989 for vessels under 25 m long may have played a major role in the increase of S. glomerata in this estuary.

Birch GF; Scammell MS; Besley CH

2013-09-01

131

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

Science.gov (United States)

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

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

1995-01-01

132

Metal behaviour in an estuary polluted by acid mine drainage: the role of particulate matter.  

UK PubMed Central (United Kingdom)

The concentrations of dissolved and suspended particulate Cd, Cu and Zn have been determined in water samples obtained during two axial transects of the Rio Tinto-Huelva Ria system in south-west Spain, which is severely impacted by acid mine drainage. Although the metal concentrations in both phases were elevated, dissolved metals were dominant and, in the upper estuary, constituted > 99% of total metal in the water column. Dissolved metals behaved non-conservatively on each transect, with maximum concentrations in the low salinity region. There was no evidence of metal adsorption within the turbidity maximum zone, despite the high specific surface areas of resuspending particles. Measurements of electrophoretic mobility showed that the suspended particulate matter (SPM) had a positive surface charge in the salinity range 0-4, where the waters had a pH < 3. Desorption experiments were carried out in which SPM from the turbidity maximum zone was resuspended in coastal seawater. The desorption of the metals was monitored for 24 h, using anodic stripping voltammetry (ASV) to detect the variation in total dissolved Cd, Cu and Zn and the species of Cu and Zn. Total dissolved Cd concentrations doubled during the incubation period, whereas the concentration of total dissolved Cu declined and that of Zn remained rather constant. The ASV-labile fraction of dissolved Cu and Zn showed an initial sharp release followed by a slower uptake. However, desorption was shown to be a minor source of dissolved metals and made little contribution to the non-conservative behaviour in the low salinity zone. The results are used to predict the effects of acid mine drainage on estuarine ecology.

Achterberg EP; Herzl VM; Braungardt CB; Millward GE

2003-01-01

133

Consequences of land use and climate changes on sediment deposition in estuaries during the last centuries  

Science.gov (United States)

Estuaries are the downstream end-member of fluvial systems. They are experiencing high sedimentation rates, thus providing good opportunities for high resolution studies of Holocene environmental changes at the land/ocean interface. From a thorough literature survey, it appears that a rapid siltation and/or an increase in sedimentation rate were recorded in many estuarine environments, concomitantly to major migrations of human population throughout the world, both in time and space. It has been clearly related to an increase in sediment supply to estuaries in Minor Asia (Bronze Age, e.g. Spezzaferri et al, 2000) and in North America and Southwest Pacific (18th and 19th centuries, e.g. Goff, 1997), in response to deforestation on catchment areas. However, this relationship is less obvious in Europe (Sorrel et al., 2009), because deforestation occurred concomitantly to climate changes of the last millennium (climate instability at the end of Medieval Warm Period, Little Ice Age) that can also explain an increase in soil erosion. Indeed, these hypotheses have been proposed to explain a similar change in Marennes-Oléron Bay (Atlantic coast of France), which consists in the sudden deposition of a few meters-thick mud drape on basal mixed mud and sand bodies (Billeaud et al., 2005). The methods used to investigate this estuarine bay so far (very high resolution seismic stratigraphy, grain size analysis and radiocarbon dating) provided relevant information about recent environmental changes, but new data are now needed for further investigation. In the present study, we provide a multi-proxy analysis of the Marennes-Oléron Bay mud drape. A new 8 m-long core (M7UC01) was sampled on an intertidal flat, its location being determined on the basis of seismic stratigraphy. Core processing included visual description, physical measurements, grain size analysis every 2.5 to 5 cm, AMS radiocarbon dating, XRF core scanning, clay mineralogy and Rock Eval analysis. Fossil molluscs and foraminifers were also recovered to provide paleoenvironmental reconstructions. Clay mineralogy of the mud drape is similar to that of the turbid plume of the Charente River, which is an important source of terrestrial sediment in the bay, and to surrounding marsh soils. Examination of sediment smear slides shows that the sediment contains abundant plant debris. The very low values of Hydrogen Index determined by Rock-Eval analysis (mean HI: 150 ± 25 mg HC.g-1 TOC) are typical of organic matter derived from land higher plants. These three results strongly suggest that the Marennes-Oléron Bay mud drape is composed of soil relicts derived from the watershed. The mud drape started to deposit at 1400 AD, which coincides with the start of the Spörer minimum. Fossil mollusc and foraminifer assemblages provide evidences of another environmental change dated to 1670 AD, which corresponds to the Maunder minimum. These data suggest a strong impact of Little Ice Age climate changes, superimposed to land reclamation and deforestation, on the increase of sediment supply in the study area. These results, compared with the detailed literature survey performed meanwhile, would provide new insights into the impact of simultaneous land use and climate changes on the sediment deposition in estuaries during the last centuries. References: Billeaud I. et al., 2005. Geo-Marine Letters 25, 1-10. Goff J.R., 1997. Marine Geology 138, 105-117. Sorrel P. et al., 2009. Quaternary Science Reviews 28, 499-516. Spezzaferri S. et al., 2000. Mediterranean Marine Science 1(1), 19-43.

Poirier, Clément; Chaumillon, Eric; Arnaud, Fabien; Goubert, Evelyne; Sauriau, Pierre-Guy; Caurant, Florence

2010-05-01

134

SAN JUAN BAY ESTUARY, COMPREHENSIVE CONSERVATION AND MANAGEMENT PLAN  

Science.gov (United States)

This Comprehensive Conservation and Management Plan (CCMP) contains information about the overall health of the San Juan Bay Estuary (SJBE) as well as proposed solutions to identified problems. These solutions, or Action Plans, are the result of a more than 4-year process of cons...

135

A Temporarily Anoxic Water Mass in an Alaska Estuary.  

Science.gov (United States)

The note reports on the occurrence of a temporary anoxic condition in Little Port Walter Estuary on southern Baranoff Island, Alaska. The condition was observed on 4 October 1971, and the mass of anoxic water was abruptly flushed out of the bay sometime b...

J. R. Knull

1973-01-01

136

Tidal variability of lateral advection in a coastal plain estuary  

Science.gov (United States)

Tidal variability of lateral advection of momentum (vuy, where u and v are along-estuary and lateral flows, respectively, and the subindex indicates differentiation with respect to the cross-estuary direction) was investigated in a coastal plain estuary with observations at Hampton Roads, which is the transition between the James River and Chesapeake Bay. Towed current velocity profiles and hydrographic profiles were captured during 9 expeditions in 2004 and 2005, to determine the intratidal and spatial changes in lateral advection of momentum and its contribution to along-channel flow. Curvature effects and lateral density gradients were important in driving lateral circulation and in modifying intratidal lateral advection of momentum. Lateral advection had the same order of magnitude as the baroclinic pressure gradient. Its contribution to the along-channel momentum balance was greatest during or just after peak flood and weakest at the end of ebb. During peak flood and peak ebb, the spatial distribution of vuy was seaward at the southern (left) side near surface and at the northern side (right) near bed (looking up-estuary), and landward in the rest of the channel. During slack periods the vuy structures were mostly landward. Observations were in good agreement with analytical model results during peak ebb and flood, but inconsistent during slack periods. The discrepancies between model results and field measurements can be attributed to bathymetry–density gradient interactions, which enhanced ebb-to-flood asymmetries in the along-channel and lateral flow.

Basdurak, N. B.; Valle-Levinson, A.

2013-07-01

137

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)

2000-01-01

138

Water and suspended sediment dynamics in Selangor River estuary  

International Nuclear Information System (INIS)

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

2001-01-01

139

ASSESSING THE ECOLOGICAL CONDITION OF VERACRUZ, MX ESTUARIES  

Science.gov (United States)

As part of an international technology transfer activity between EPA's Office of Research and Development and the state of Veracruz's Sub-secretary of the Environment, 50 stations within estuaries along the gulf coast of the state of Veracruz MX, were sampled during June and July...

140

Plutonium isotope ratios in the Yenisey and Ob estuaries  

International Nuclear Information System (INIS)

Over the past 50 years, nuclear weapons' tests and releases from the nuclear industry have introduced anthropogenic plutonium into the environment. In the Arctic environment, the main source of plutonium is from the atmospheric weapons testing, but previous studies of plutonium in the Kara Sea have shown that, at certain sites, other releases can give rise to enhanced local concentrations. The present paper presents results from determination of plutonium concentrations and isotope ratios in the sediment samples collected during various expeditions to the Kara Sea, the Ob and Yenisey estuaries and their river systems. The data indicated a clear influence from a low 240Pu:239Pu source in surface sediments collected from the Yenisey estuary, whereas plutonium in Ob estuary sediments is dominated by global fallout. The results also show an increase in plutonium concentration (from 0.003 to 11 Bq/kg) and a decrease in 240Pu:239Pu isotope ratio (from 0.16 to 0.05) going upstream from the Yenisey estuary towards the nuclear installation at Krashnoyarsk.

2004-01-01

 
 
 
 
141

Plutonium isotope ratios in the Yenisey and Ob estuaries  

Energy Technology Data Exchange (ETDEWEB)

Over the past 50 years, nuclear weapons' tests and releases from the nuclear industry have introduced anthropogenic plutonium into the environment. In the Arctic environment, the main source of plutonium is from the atmospheric weapons testing, but previous studies of plutonium in the Kara Sea have shown that, at certain sites, other releases can give rise to enhanced local concentrations. The present paper presents results from determination of plutonium concentrations and isotope ratios in the sediment samples collected during various expeditions to the Kara Sea, the Ob and Yenisey estuaries and their river systems. The data indicated a clear influence from a low {sup 240}Pu:{sup 239}Pu source in surface sediments collected from the Yenisey estuary, whereas plutonium in Ob estuary sediments is dominated by global fallout. The results also show an increase in plutonium concentration (from 0.003 to 11 Bq/kg) and a decrease in {sup 240}Pu:{sup 239}Pu isotope ratio (from 0.16 to 0.05) going upstream from the Yenisey estuary towards the nuclear installation at Krashnoyarsk.

Skipperud, L. E-mail: lindis.skipperud@ipm.nlh.no; Oughton, D.H.; Fifield, L.K.; Lind, O.C.; Tims, S.; Brown, J.; Sickel, M

2004-04-01

142

Plutonium isotope ratios in the Yenisey and Ob estuaries.  

Science.gov (United States)

Over the past 50 years, nuclear weapons' tests and releases from the nuclear industry have introduced anthropogenic plutonium into the environment. In the Arctic environment, the main source of plutonium is from the atmospheric weapons testing, but previous studies of plutonium in the Kara Sea have shown that, at certain sites, other releases can give rise to enhanced local concentrations. The present paper presents results from determination of plutonium concentrations and isotope ratios in the sediment samples collected during various expeditions to the Kara Sea, the Ob and Yenisey estuaries and their river systems. The data indicated a clear influence from a low 240Pu:239Pu source in surface sediments collected from the Yenisey estuary, whereas plutonium in Ob estuary sediments is dominated by global fallout. The results also show an increase in plutonium concentration (from 0.003 to 11Bq/kg) and a decrease in 240Pu:239Pu isotope ratio (from 0.16 to 0.05) going upstream from the Yenisey estuary towards the nuclear installation at Krashnoyarsk. PMID:14987709

Skipperud, L; Oughton, D H; Fifield, L K; Lind, O C; Tims, S; Brown, J; Sickel, M

143

5.04 - Carbon Dioxide and Methane Dynamics in Estuaries  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Estuaries profoundly transform the large amounts of carbon delivered from rivers before their transfer to the adjacent coastal zone. As a consequence of the complex biogeochemical reworking of allochthonous carbon in the sediments and the water column, CO2 and CH4 are emitted into the atmosphere. We...

Borges, Alberto; Abril, Gwenaël

144

Initial growth of phytoplankton in turbid estuaries: a simple model  

Digital Repository Infrastructure Vision for European Research (DRIVER)

An idealised model is presented and analysed to gain more fundamental understanding about the dynamics of phytoplankton blooms in well-mixed, suspended sediment dominated estuaries. The model describes the behaviour of subtidal currents, suspended sediments, nutrients and phytoplankton in a channel ...

Swart, H.E. de; Schuttelaars, H.; Talke, S.A.

145

Biogeochemistry of the Tana estuary and delta (northern Kenya)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The estuarine mixing zone of the Tana River (northern Kenya) and an extensive deltaic area just south of the estuary were sampled in April 2004 with the aim of identifying the distribution, sources, and processing of particulate and dissolved organic carbon (POC, DOC) and inorganic carbon (DIC). C4 ...

Bouillon, S.; Dehairs, F.; Schiettecatte, L.-S.; Borges, A.V.

146

The dynamics of a frictionally-dominated Amazonian estuary  

Directory of Open Access Journals (Sweden)

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.

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

2012-01-01

147

Biogeochemical value of managed realignment, Humber estuary, UK  

International Nuclear Information System (INIS)

[en] 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

1000-01-00

148

76 FR 15307 - Notice of Staff Attendance at Southwest Power Pool Strategic Planning Committee Meeting  

Science.gov (United States)

...Notice of Staff Attendance at Southwest Power Pool Strategic Planning Committee Meeting The Federal Energy Regulatory...meeting of the Southwest Power Pool, Inc. (SPP) Strategic Planning Committee (SPC), as noted below. Their...

2011-03-21

149

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

UK PubMed Central (United Kingdom)

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

Sun J; Zhao R; Zhang LY

2011-04-01

150

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

Science.gov (United States)

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

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

2011-04-01

151

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...

152

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...

153

Response of the turbidity maximum zone to fluctuations in sediment discharge from river to estuary in the Changjiang Estuary (China)  

Science.gov (United States)

In the Changjiang Estuary, interactions between the sea and the river result in the development of a turbidity maximum zone (TMZ). Riverine sediments are an important source for TMZ formation. Since the 1960s, sediment discharge from the river basin to the estuary has decreased due to dam construction, water and soil conservation, and water diversion projects. Thirty-two Landsat images of the estuary, covering the period from 1979 to 2008, were collected to identify the TMZ response to sediment decline. A threshold value of suspended sediment concentration (SSC) of 0.7 kg/m3, corresponding to a spectrum reflectance of 5% of Landsat MSS band 7 and 7% of Landsat TM/ETM band 4, was used to identify the Changjiang Estuary TMZ. The TMZ area was then extracted from each image to investigate its temporal and spatial variations during the past 30 years. The images were grouped into five time series; the average TMZ area of each series was estimated. The results show that the TMZ area declined 23% from series (a) to series (e), responding to a 77% reduction in riverine sediment discharge. In addition, the TMZ had strong seasonal and tidal variations; it was generally larger during flood seasons than during dry seasons and during spring tides compared to neap tides. The spring/neap tidal cycle played a more important role in TMZ change than did the seasonal cycle. Due to the continued reduction of sediment discharge to the estuary resulting from dams already constructed and to those that will be constructed upstream in the Changjiang River, it is predicted that the TMZ area will continue decreasing and that the re-suspension of local sediments will play a more important role in the formation of the TMZ.

Jiang, Xuezhong; Lu, Bing; He, Yuhong

2013-10-01

154

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

2008-02-20

155

Retail Demand Response in Southwest Power Pool  

Energy Technology Data Exchange (ETDEWEB)

In 2007, the Southwest Power Pool (SPP) formed the Customer Response Task Force (CRTF) to identify barriers to deploying demand response (DR) resources in wholesale markets and develop policies to overcome these barriers. One of the initiatives of this Task Force was to develop more detailed information on existing retail DR programs and dynamic pricing tariffs, program rules, and utility operating practices. This report describes the results of a comprehensive survey conducted by LBNL in support of the Customer Response Task Force and discusses policy implications for integrating legacy retail DR programs and dynamic pricing tariffs into wholesale markets in the SPP region. LBNL conducted a detailed survey of existing DR programs and dynamic pricing tariffs administered by SPP's member utilities. Survey respondents were asked to provide information on advance notice requirements to customers, operational triggers used to call events (e.g. system emergencies, market conditions, local emergencies), use of these DR resources to meet planning reserves requirements, DR resource availability (e.g. seasonal, annual), participant incentive structures, and monitoring and verification (M&V) protocols. Nearly all of the 30 load-serving entities in SPP responded to the survey. Of this group, fourteen SPP member utilities administer 36 DR programs, five dynamic pricing tariffs, and six voluntary customer response initiatives. These existing DR programs and dynamic pricing tariffs have a peak demand reduction potential of 1,552 MW. Other major findings of this study are: o About 81percent of available DR is from interruptible rate tariffs offered to large commercial and industrial customers, while direct load control (DLC) programs account for ~;;14percent. o Arkansas accounts for ~;;50percent of the DR resources in the SPP footprint; these DR resources are primarily managed by cooperatives. o Publicly-owned cooperatives accounted for 54percent of the existing DR resources among SPP members. For these entities, investment in DR is often driven by the need to reduce summer peak demand that is used to set demand charges for each distribution cooperative. o About 65-70percent of the interruptible/curtailable tariffs and DLC programs are routinely triggered based on market conditions, not just for system emergencies. Approximately, 53percent of the DR resources are available with less than two hours advance notice and 447 MW can be dispatched with less than thirty minutes notice. o Most legacy DR programs offered a reservation payment ($/kW) for participation; incentive payment levels ranged from $0.40 to $8.30/kW-month for interruptible rate tariffs and $0.30 to $4.60/kW-month for DLC programs. A few interruptible programs offered incentive payments which were explicitly linkedto actual load reductions during events; payments ranged from 2 to 40 cents/kWh for load curtailed.

Bharvirkar, Ranjit; Heffner, Grayson; Goldman, Charles

2009-01-30

156

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

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese 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 (more) 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 (more) 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.

Schettini, Carlos Augusto França; Miranda, Luiz Bruner de

2010-03-01

157

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

Directory of Open Access Journals (Sweden)

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.

Carlos Augusto França Schettini; Luiz Bruner de Miranda

2010-01-01

158

An analytical solution for tidal propagation in the Yangtze Estuary, China  

Directory of Open Access Journals (Sweden)

Full Text Available An analytical model for tidal dynamics has been applied to the Yangtze Estuary for the first time, to describe the tidal propagation in this large and typically 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. Within the same estuary system, the North Branch and the South Branches have a distinct tidal behaviour: the former being amplified demonstrating a marine character and the latter being damped with a riverine character. The satisfactory results for the South Channel and the South Branch using both separate and combined topographies confirm that the branched estuary system functions as an entity. To further test these results, it is suggested to collect more accurate and dense bathymetric and tidal information.

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

2012-01-01

159

Wolf predation in the Burwash caribou herd, southwest Yukon  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The role of wolf predation as a proximate mortality factor influencing caribou herd growth was assessed in the Burwash herd (400 animals) in the southwest Yukon between 1980 - 1982. Ten to 14 wolves in two packs preyed primarily on caribou (Rangifer tarandus caribou) and moose (Alces alces) with dis...

David A. Gauthier; John B. Theberge

160

CD-SOUTHWEST WATERSHED RESEARCH CENTER ONLINE DATA ACCESS 1606  

Science.gov (United States)

Hydrologic data, including rainfall and runoff data, have been collected on the Walnut Gulch Experimental Watershed since the 1950s. These data are of national and international importance and make up the most comprehensive semi-arid watershed dataset in the world. The USDA-ARS Southwest Watershed R...

 
 
 
 
161

Sources, sinks and distribution of organic carbon in the St. Lawrence Estuary, Canada  

Energy Technology Data Exchange (ETDEWEB)

Carbon isotope ratio analysis of particulate, planktonic, and sedimentary organic carbon and dissolved inorganic carbon has been used to study the sources and sinks of the organic carbon in the St. Lawrence Estuary and Gulf of St. Lawrence, Canada. Particulate organic carbon (POC) isotope ratios in the upper St. Lawrence Estuary are uniform and indistinguishable from those of POC in the St. Lawrence River and of planktonic organic carbon in both areas. The abundance of freshwater diatoms in the upper Estuary suggests that upper Estuary POC is predominantly ''fresh'' organic matter of riverborne origin. Upper Estuary POC is isotopically different from POC in the lower St. Lawrence. The isotopic composition of planktonic organic carbon mirrors that of the POC, indicating that the POC in the lower Estuary and Gulf is also ''fresh'' organic matter. Since the lower Estuary POC forms an isotopic barrier between the upper Estuary POC and the Gulf of St. Lawrence POC, there appears to be little mixing of POC between these three reservoirs.Therefore PC in the lower Estuary and Gulf is most likely both produced and deposited (or degraded) in situ. An examination of carbon isotope ratio differences between the planktonic and dissolved inorganic carbon reservoirs shows that this difference varies significantly and somewhat unpredictably between sectors of the study area. Interpretation of environmental carbon isotope data on the basis of an assumed, constant fractionation factor may be subject to large errors. Direct measurement of both resrvoirs is obviously preferable.

Tan, F.C.; Strain, P.M.

1983-01-01

162

Physico-chemical characteristics of the Vellar estuary in relation to shrimp farming.  

Science.gov (United States)

All the physico-chemical parameters such as temperature, LEC, salinity, pH, dissolved oxygen and nutrients like total phosphorus, inorganic phosphate, nitrite and silicate studied in relation to shrimp farming. There are as many as 42 shrimp farms situated on the banks of Vellar estuary. These farms discharge the used water into the estuary, which may influence the biota there. In the present study the physico-chemical feature in relation to shrimp farming were studied in 3 stations of the estuary. When compared with the previous data from Vellar estuary there was no much difference in physico-chemical characteristics due to shrimp farming. PMID:12974418

Rajasegar, M

2003-01-01

163

???????????????? Research on Changes of Peak Water Level in the Pearl River Estuary  

Digital Repository Infrastructure Vision for European Research (DRIVER)

???????????????????????????????????????????????????????????????????????1) 20??50???????????????????????????2) ???????????????20??90???????????????????????????????????????1981??1983??3) ??????????????????????????????????? Higher peak water level of the Pearl River Estuary gives a great t...

??; ???; ???; ???; ???; ???

164

Macrobenthic community in the Xiaoqing River Estuary in Laizhou Bay, China  

Science.gov (United States)

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

Luo, Xianxiang; Zhang, Shanshan; Yang, Jianqiang; Pan, Jinfen; Tian, Lin; Zhang, Longjun

2013-09-01

165

Preliminary survey of tidal energy of U. K. estuaries  

Energy Technology Data Exchange (ETDEWEB)

The studies being carried out at the present time of tidal power schemes in the Severn estuary have resulted in the development of quick, reasonably accurate methods of assessing their energy outputs, likely cost and hence economic performance in terms of the cost of the energy produced. These methods have been applied to the six other UK estuaries having a reasonable combination of area and tidal range. The results show that Morecambe Bay and Solway Firth are large energy resources which would produce their energy out of phase with an ebb generation scheme in the Severn. A scheme in Morecambe Bay could produce energy nearly as cheaply as the second stage of the Severn scheme.

1980-05-01

166

TSUNAMI PROPAGATION ALONG TAGUS ESTUARY (LISBON, PORTUGAL) PRELIMINARY RESULTS  

Directory of Open Access Journals (Sweden)

Full Text Available In this study we present preliminary results of flood calculation along Tagus Estuary, a catastrophic event that happened several times in the past, as described in historical documents, and that constitutes one of the major risk sources for Lisbon coastal area. To model inundation we used Mader’s SWAN model for the open ocean propagation with a 2 km grid, and Imamura’s TSUN2 with a 50 m grid covering the entire estuary. The seismic source was computed with the homogeneous elastic half space approach. Modelling results agree with historical reports. Synthetic flood areas correspond to the sites where there are morphological and sedimentary evidences of two known major events that stroke Lisbon: 1531-01-26 and 1755-11-01 tsunamis.

M. A. Viana-Baptista; P. M.. Soares; J. M. Miranda; J. F. Luis

2006-01-01

167

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

2007-01-01

168

Tritium in the Savannah River estuary and adjacent marine waters  

International Nuclear Information System (INIS)

The purpose of this paper is to report the results of a study on the tritium distribution in the Savannah River estuary, inland marine waters, and coastal waters. Tritium is released to surface streams from the Savannah River Plant reactor area fuel and target storage basins, and indirectly by discharge to seepage basins with a fraction ultimately discharged to streams by groundwater transport. Previously tritium has been used to determine the travel time and dispersion coefficients for the Savannah River

1976-06-21

169

Hydrographic and chemical observations in the Sierra Leone River estuary  

International Nuclear Information System (INIS)

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

1979-01-01

170

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.

1994-09-02

171

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

Science.gov (United States)

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

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

2013-06-05

172

Counting on ?-Diversity to Safeguard the Resilience of Estuaries  

Science.gov (United States)

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

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

2013-01-01

173

Local flows in the Quequen Grande River Estuary, Argentina  

International Nuclear Information System (INIS)

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.

2009-05-01

174

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

UK PubMed Central (United Kingdom)

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

de Juan S; Thrush SF; Hewitt JE

2013-01-01

175

76 FR 9709 - Water Quality Challenges in the San Francisco Bay/Sacramento-San Joaquin Delta Estuary  

Science.gov (United States)

...sources or impacts of total ammonia nitrogen in the Bay Delta Estuary that...quality standards for total ammonia nitrogen in the Bay Delta Estuary may...quality standards for total ammonia nitrogen, including narrative or...

2011-02-22

176

Autotrophic and heterotrophic food sources of copepods in the Scheldt estuary as traced by stable C and N isotopes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Estuaries draining densely populated watersheds experience significant anthropogenic pressure and sustain large autotrophic and heterotrophic production owing to an increased input of nutrients and organic matter. Polluted estuaries are often net heterotrophic systems. Our objective was to study the...

De Brabandere, L.

177

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

Science.gov (United States)

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

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

2012-11-24

178

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

Science.gov (United States)

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

179

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

Science.gov (United States)

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

180

An examination of Southwest Pacific explosive cyclones, 1989 to 2009  

International Nuclear Information System (INIS)

This study has assembled a climatology of Southwest Pacific explosively developing cyclones, based on the European Centre for Medium-Range Weather Forecasts' ERA-Interim reanalysis data, over the 21-year period from 1989 to 2009. The recently developed 'combined explosive' expression, a refinement of the 'relative explosive' criterion, was used to identify cyclones deemed explosive with respect to both the drop in central pressure and the climatological pressure gradient. Over the period of analysis, 47 explosive cyclones were identified within the Southwest Pacific, equating to an average of 2.2 explosive events per year. Seasonally, explosive cyclones are most frequent during the winter months, while least frequent during the summer. Two case explosive systems are briefly considered, with their corresponding measures of intensity and scale placed into climatological perspective.

2010-01-01

 
 
 
 
181

Light-induced bird strikes on vessels in Southwest Greenland  

DEFF Research Database (Denmark)

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.

Merkel, Flemming Ravn; Johansen, Kasper Lambert

2011-01-01

182

Update on the Southwest 1000 MW CSP Initiative  

Energy Technology Data Exchange (ETDEWEB)

The 1000 MW CSP project was initiated in FY02 based on a Congressional request of the DOE to investigate the feasibility of 1000 MW of Concentrating Solar Power in the Southwest by 2006. The original charge has grown and involved a number of activities including: outreach to the SW states, support of state-level activities in NM, CA, and CO, and analysis in support of the Western Governors' Association (WGA) 30 GW Clean Energy Initiative.

Mancini, T.; Mehos, M.; Wilkins, F.; Morse, F.

2005-11-01

183

Migmatitic rocks southwest of the Barberton greenstone belt  

International Nuclear Information System (INIS)

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

1981-01-01

184

The effect of interacting downstream branches on saltwater intrusion in the Modaomen Estuary, China  

Science.gov (United States)

In recent years, the increased pressure of saltwater intrusion in the Modaomen Estuary, one of the outlets in the Pearl River Delta (PRD), China, has threatened the freshwater supply for the surrounding regions. The estuary has complex geometry and bathymetry and branches into three waterways, Madaomen Waterway, Hongwan Waterway, and Hezhou Waterway, entering into the coastal sea. In this study, a three-dimensional baroclinic model (EFDC) was used to investigate salt transport among these branches and saltwater intrusion in the mainstem of the estuary. The salt transport at selected cross sections was decomposed into three components: advection, steady shear, and tidal oscillatory, following the method of Lerczak et al. (Lerczak, J.A., Geyer, W.R., Chant, R.J., 2006. Mechanisms driving the time-dependent salt flux in a partially stratified estuary. Journal of Physical Oceanography 36, 2296-2311). Results from this study indicate that the Hongwan Waterway serves as a salt source for the mainstem of the estuary, especially during spring tides, while the Hezhou Waterway mainly acts as a salt sink for the mainstem. The down-estuary wind increases the steady shear transport in the Modaomen Waterway and the advection transport in the Hongwan Waterway, which alters the saltwater intrusion in the estuary. Closure of the Hongwan and the Hezhou Waterways could result in a 20% decrease of saltwater intrusion in the estuary. These results provide scientific basis for water resource management in the region.

Gong, Wenping; Wang, Yaping; Jia, Jianjun

2012-02-01

185

Distribution of carbon in a tropical hypersaline estuary, the Casamance (Senegal, West Africa)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The Casamance estuary, on the coast of Senegal, is an inverse hypersaline estuary : salinity increases landward, and dry season salinity values are up to 172 psu due to the evaporation of seawater. Dissolved inorganic carbon (DIC) concentrations decreased landward as a negative linear function of sa...

Pagès, Jean; Lemoalle, Jacques

186

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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....

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

187

The relationship between dissolved humic acids and soluble iron in estuaries  

Science.gov (United States)

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

Fox, L. E.

1984-04-01

188

Spatial and temporal dynamics of phytoplankton communities in a freshwater tidal estuary (Schelde, Belgium)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

During the course of 1996, the brackish to freshwater tidal reaches of the Schelde Estuary were sampled monthly along a longitudinal transect to study the origin and composition of phytoplankton communities in the freshwater tidal estuary. Variation in the phytoplankton community as a whole and its ...

Muylaert, K.; Sabbe, K.; Vyverman, W.

189

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

Science.gov (United States)

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

190

An analytical solution for tidal propagation in the Yangtze Estuary, China  

Digital Repository Infrastructure Vision for European Research (DRIVER)

An analytical model for tidal dynamics has been applied to the Yangtze Estuary for the first time, to describe the tidal propagation in this large and typically branched estuary with three-order branches and four outlets to the sea. This study shows that the analytical model developed for a single-c...

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

191

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Huijts, K.M.H.

192

RELATIONSHIPS BETWEEN SEAGRASSES, BENTHIC MACROALGAE AND NUTRIENTS IN A PACIFIC NORTHWEST ESTUARY  

Science.gov (United States)

Pacific Northwest estuaries are characterized by large tidal ranges (2-3 m) that routinely expose submerged aquatic vegetation (SAV) such as seagrass and benthic macroalgae. The dominant native seagrass in PNW estuaries is the eelgrass Zostera marina. However, in recent decades...

193

Pennsylvanian foreland deformation of Wichita uplift, southwest Oklahoma  

Energy Technology Data Exchange (ETDEWEB)

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

McConnell, D.

1986-05-01

194

SALT WATER INTRUSION AND ITS RELATIONSHIP WITH ESTUARINE ECOLOGY IN THE CHIKUGOGAWA ESTUARY  

Science.gov (United States)

The spatiotemporal distribution of seawater intrusion in the Chikugogawa estuary was analyzed, and its relationship with the temporal variation of phytoplankton and engraulid fish, Coilia nasus, was discussed. The Chikugogawa estuary is vertically well mixed for most of the year, and a salt wedge is observed only when the tidal range decreases to 2 m or less. We found that the ratio of chlorophyll-a to pheophytin-a during the semilunar cycle varied according to the change in the mixing conditions in the estuary. Further, the number of sampled estuarine fish was related to the salinity and tidal range within the estuary; the fish was caught when the salinity was low and the tidal range was large. It is necessary to regulate the fresh water discharge in the estuary in order to maintain a low-salinity region that is suitable for the migration of fish and their spawning areas to the downstream of the river mouth barrage.

Yokoyama, Katsuhide; Ohmura, Taku; Suzuki, Tomoyuki; Takashima, Soutaro

195

Detecting benthic community responses to pollution in estuaries: a field mesocosm approach.  

UK PubMed Central (United Kingdom)

Biological stress responses in individuals are used as indicators of pollution in aquatic ecosystems, but detecting ecologically relevant responses in whole communities remains a challenge. We developed an experimental approach to detect the effects of pollution on estuarine communities using field-based mesocosms. Mesocosms containing defaunated sediments from four estuaries in southeastern Australia that varied in sediment contamination were transplanted and buried in sediments of the same four estuaries for six weeks. Mesocosm sediment properties and metal concentrations remained representative of their source locations. In each estuary, fauna communities associated with sediments derived from the site with the highest metal concentrations were significantly different from other communities. This pattern was evident for some of the individual taxa, in particular the polychaete Capitella sp. Consistent responses across estuaries suggest numbers of individuals, and especially Capitella sp., could be used to identify contaminated sediments in estuaries with similar fauna and site characteristics.

O'Brien AL; Keough MJ

2013-04-01

196

Detecting benthic community responses to pollution in estuaries: a field mesocosm approach.  

Science.gov (United States)

Biological stress responses in individuals are used as indicators of pollution in aquatic ecosystems, but detecting ecologically relevant responses in whole communities remains a challenge. We developed an experimental approach to detect the effects of pollution on estuarine communities using field-based mesocosms. Mesocosms containing defaunated sediments from four estuaries in southeastern Australia that varied in sediment contamination were transplanted and buried in sediments of the same four estuaries for six weeks. Mesocosm sediment properties and metal concentrations remained representative of their source locations. In each estuary, fauna communities associated with sediments derived from the site with the highest metal concentrations were significantly different from other communities. This pattern was evident for some of the individual taxa, in particular the polychaete Capitella sp. Consistent responses across estuaries suggest numbers of individuals, and especially Capitella sp., could be used to identify contaminated sediments in estuaries with similar fauna and site characteristics. PMID:23333486

O'Brien, Allyson L; Keough, Michael J

2013-01-16

197

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)

|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…

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

2007-01-01

198

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)

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…

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

2007-01-01

199

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)

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.

Lund-Hansen, Lars Chresten; Nhu Hai, Doan

2010-01-01

200

Measurement frequency and sampling spatial domains required to characterize turbidity and salinity events in the Guadalquivir estuary (Spain)  

Directory of Open Access Journals (Sweden)

Full Text Available Estuaries are complex systems in which long water quality data series are not always available at the proper scale. Data proceeding from several water quality networks, with different measuring frequencies (monthly, weekly and 15 min) and different numbers of sampling points, were compared throughout the main channel of the Guadalquivir estuary. Higher frequency of turbidity sampling in the upper estuary is required. In the lower estuary, sampling points help to find out the ETM, and higher frequency sampling of EC is required because of the effect of the tidal and river components. This could be a feedback for the implementation of monitoring networks in estuaries.

E. Contreras; M. J. Polo

2012-01-01

 
 
 
 
201

Nutrient transport to the Swan - Canning Estuary, Western Australia  

Science.gov (United States)

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.

Peters, N. E.; Donohue, R.

2001-01-01

202

Environmental contaminants in bald eagles in the Columbia River estuary  

Energy Technology Data Exchange (ETDEWEB)

Eggs, blood, and carcasses of bald eagles (Haliaeetus leucocephalus) and fish were collected and breeding success of eagles was monitored in the Columbia River estuary, 1980-87, to determine if contaminants were having an effect on productivity. High levels of dichloro diphenyl dichloroethylene (DDE), polychlorinated biphenyls (PCB's), and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) were found in eggs, blood from adults, and 2 eagle carcasses. Detectable levels of DDE and PCB's were found in blood of nestlings indicating they were exposed to these contaminants early in life. Increasing concentrations of DDE and PCB's with age also indicated accumulation of these contaminants. Adult eagles also had higher levels of mercury (Hg) in blood than subadults or young indicating accumulation with age. The high levels of DDE and PCB's were associated with eggshell thinning ([bar x] = 10%) and with productivity ([bar x] = 0.56 young/occupied site) that was lower than that of healthy populations (i.e., [ge]1.00 young/occupied site). DDE and PCB's had a deleterious effect on reproduction of bald eagles in the estuary. The role dioxins play in eagle reproduction remains unclear, but concentrations in eagle eggs were similar to those in laboratory studies on other species where dioxins adversely affected hatchability of eggs. Probable source of these contaminants include dredged river sediments and hydroelectric dams, and the proper management of each may reduce the amount of contaminants released into the Columbia River estuary. 46 refs., 1 fig., 4 tabs.

Anthony, R.G.; Garrett, M.G. (Oregon State Univ., Corvallis (United States)); Schuler, C.A. (Fish and Wildlife Service, Portland, OR (United States))

1993-01-01

203

The risk of harmful algal blooms (HABs) in the oyster-growing estuaries of New South Wales, Australia.  

Science.gov (United States)

The spatial and temporal variability of potentially harmful phytoplankton was examined in the oyster-growing estuaries of New South Wales. Forty-five taxa from 31 estuaries were identified from 2005 to 2009. Harmful species richness was latitudinally graded for rivers, with increasing number of taxa southward. There were significant differences (within an estuary) in harmful species abundance and richness for 11 of 21 estuaries tested. Where differences were observed, these were predominately due to species belonging to the Pseudo-nitzschia delicatissima group, Dinophysis acuminata, Dictyocha octonaria and Prorocentrum cordatum with a consistent upstream versus downstream pattern emerging. Temporal (seasonal or interannual) patterns in harmful phytoplankton within and among estuaries were highly variable. Examination of harmful phytoplankton in relation to recognised estuary disturbance measures revealed species abundance correlated to estuary modification levels and flushing time, with modified, slow flushing estuaries having higher abundance. Harmful species richness correlated with bioregion, estuary modification levels and estuary class, with southern, unmodified lakes demonstrating greater species density. Predicting how these risk taxa and risk zones may change with further estuary disturbance and projected climate warming will require more focused, smaller scale studies aimed at a deeper understanding of species-specific ecology and bloom mechanisms. Coupled with this consideration, there is an imperative for further taxonomic, ecological and toxicological investigations into poorly understood taxa (e.g. Pseudo-nitzschia). PMID:23111868

Ajani, Penelope; Brett, Steve; Krogh, Martin; Scanes, Peter; Webster, Grant; Armand, Leanne

2012-10-31

204

Nutrient budgets for large Chinese estuaries and embayment  

Directory of Open Access Journals (Sweden)

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

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

2009-01-01

205

Depletion, degradation, and recovery potential of estuaries and coastal seas.  

UK PubMed Central (United Kingdom)

Estuarine and coastal transformation is as old as civilization yet has dramatically accelerated over the past 150 to 300 years. Reconstructed time lines, causes, and consequences of change in 12 once diverse and productive estuaries and coastal seas worldwide show similar patterns: Human impacts have depleted >90% of formerly important species, destroyed >65% of seagrass and wetland habitat, degraded water quality, and accelerated species invasions. Twentieth-century conservation efforts achieved partial recovery of upper trophic levels but have so far failed to restore former ecosystem structure and function. Our results provide detailed historical baselines and quantitative targets for ecosystem-based management and marine conservation.

Lotze HK; Lenihan HS; Bourque BJ; Bradbury RH; Cooke RG; Kay MC; Kidwell SM; Kirby MX; Peterson CH; Jackson JB

2006-06-01

206

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

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese 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 jun (more) to 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 methodology involved various techniques: free interviews and semi-structured ones, guided tours and direct observations. The results obtained show the fishermen's classification of t (more) he 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.

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

2012-09-01

207

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)

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.

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

2012-01-01

208

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

Science.gov (United States)

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

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

2013-04-01

209

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

DEFF Research Database (Denmark)

To unravel the factors that regulate DOC dynamics in the freshwater tidal reaches of the Schelde estuary, DOC concentration and biodegradability were monitored in the upper Schelde estuary and its major tributaries. Although the Schelde estuary possesses a densely populated and industrialized catchment, our data suggest that the bulk of DOC in the freshwater tidal reaches is not derived from waste water. This was concluded from the low biodegradability of DOC (on average 9%), DOC concentrations that are close to the mean for European rivers (4.61 mg/l) and the absence of an inverse relationship between DOC and discharge. Most DOC originating from waste water being discharged in tributaries of the estuary appears to be remineralised before these tributaries reach the main estuary. Although dense phytoplankton blooms were observed in the upper estuary during summer (up to 700 mg chl a/l), these blooms did not appear to produce large quantities of DOC in the freshwater tidal reaches as DOC concentrations were low when phytoplankton biomass was high. The fact that DOC concentrations were high in winter and decreased in summer suggests a predominantly terrestrial source of DOC in the freshwater tidal reaches of the Schelde estuary.

Muylaert, K.; Dasseville, R.

2005-01-01

210

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 celerity, and the velocity amplitude along the estuary can be computed. Within the same estuary system, the North Branch and the South Branches have a distinct tidal behavior: the former being amplified demonstrating a marine character and the latter being damped with a riverine character. The satisfactory results for the South Channel and the South Branch using both separate and combined topographies confirm that the branched estuary system functions as an entity. To further test these results, it is suggested to collect more accurate and dense bathymetric and tidal information.

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

2012-01-01

211

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

Directory of Open Access Journals (Sweden)

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.

Arefe Emami; Mojtaba Tajziyehchi

2012-01-01

212

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

Directory of Open Access Journals (Sweden)

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.

Arefe Emami; Mojtaba Tajziyehchi

2013-01-01

213

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.

2011-01-01

214

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

Energy Technology Data Exchange (ETDEWEB)

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.

Dion, E.P.

1983-01-01

215

Bioenergy in the Southwest: potentials and unique aspects  

Energy Technology Data Exchange (ETDEWEB)

An assessment is presented of the potential of biomass energy in the Southwest, which is defined as the seven Sunbelt States and Hawaii. This region is responsible for about one-quarter of US energy and petroleum consumption, and one-third of US natural gas consumption. Hawaii, the state with the smallest areas and population and no fossil fuel resources, has the lowest per-capita energy consumption and the smallest areas devoted to farming. The largest state, Texas, has one of the highest populations, large fossil fuel deposits, the highest per-capita energy consumption, and the largest area devoted to farming. Of the major parameters that govern biomass productivity in the Sunbelt States, water is the limiting factor. The US Geological Service believes consumptive use of water in most areas of the Sunbelt States is excessive. Indigenous organic wastes can make valuable contributions to energy demands, but are not large enough to satisfy the entire demand of each state. Incremental new growth on rangelands used for grassy species and forest land is projected to be capable of making large contributions to energy requirements. In the arid to semi-arid regions of the Southwest, current technology seems to offer two options: biomass production at low yields without irrigation for high value chemicals, and biomass production at higher yields with irrigation for energy. Future options include microalgae and macroalgae production in saline and brackish waters, and use of low-cost mulches to conserve water for land biomass growth. Various biomass energy species of special interest for the Southwest include desert perennials, selected tree species many of which fix nitrogen and are capable of coppice growth, and certain warm-season grasses. 26 refs., 16 tabs.

Klass, D.L.

1985-01-01

216

High frequency ocean acoustic tomography observation at coastal estuary areas  

Science.gov (United States)

The ocean acoustic tomography (OAT) technique can obtain oceanographic information and has received much interest. High frequency OAT (in a narrow kHz range) can be used for small and confined areas, such as estuaries and bays, with complicated hydrological conditions. In this study, we investigate the application of high-frequency reciprocal transmission OAT to assess the sound speed, temperature, and current field in the Xiamen sea area using computer simulations and sea experiments. Based on the temperature data obtained from remote sensing and the predefined stream function, high frequency OAT is employed to reconstruct the two-dimensional sound speed, temperature, and current fields of a 1.2km×1.2km small-scale region. The correlation coefficient of the computer inversion result and the original data is higher than 0.8. The result shows that increasing the number of acoustic stations decreases the influence of the travel-time errors in high frequency OAT; however, excessively increasing the number of stations could not significantly improve the inversion accuracy. Furthermore, this method has been tested by a sea experiment on monitoring the shallow water temperature of Wuyuan Bay. High frequency OAT might provide an effective method for temperature and current observation at coastal estuary areas.

Zhao, Zongxi; Zhang, Yu; Yang, Wuyi; Chen, Dongsheng

2012-11-01

217

Mathematical simulation of sediment and radionuclide transport in estuaries  

Energy Technology Data Exchange (ETDEWEB)

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.

Onishi, Y.; Trent, D.S.

1982-11-01

218

Spatial variation of the longitudinal dispersion coefficient in an estuary  

Directory of Open Access Journals (Sweden)

Full Text Available The effective longitudinal dispersion is a primary tool for determining property distributions in estuaries. Most previous studies have examined the longitudinal dispersion coefficient for the average tidal condition. However, information on spatial and temporal variations of this coefficient at low and high tides is scarce. Three years of hydrographic data taken at low and high tide along the main axis of the Sumjin River Estuary (SRE), Korea are used to estimate the spatial and temporal variation of the effective longitudinal dispersion coefficient. The range of the dispersion coefficient is rather broad at high water slack (HWS) and narrower at low water slack (LWS) because of the different tidal amplitudes. The spatially varying dispersion coefficient has maximal values (>300 m2 s?1) near the mouth at high water and decreases gradually upstream, with fluctuations. The temporally varying dispersion coefficient appears to be positively correlated with river discharges at both low and high tide. The dispersion varies with the square root of river discharges at HWS and LWS. The dispersive salt fluxes increases with increasing river discharges and decreases with decreasing river discharges at HWS and LWS. Estimation of the numerical values of the effective longitudinal dispersion coefficient in the SRE can be useful for better understanding of the distributions of other tracers in the SRE as well as for developing and testing hypotheses about various mixing mechanisms.

D. C. Shaha; Y.-K. Cho; M.-T. Kwak; S. R. Kundu; K. T. Jung

2011-01-01

219

Spatial variation of the longitudinal dispersion coefficient in an estuary  

Directory of Open Access Journals (Sweden)

Full Text Available The effective longitudinal dispersion is a primary tool for determining property distributions in estuaries. Most previous studies have examined the longitudinal dispersion coefficient for the average tidal condition. However, information on spatial and temporal variations of this coefficient at low and high tide is scarce. Three years of hydrographic data taken at low and high tide along the main axis of the Sumjin River Estuary (SRE), Korea are used to estimate the spatial and temporal variation of the effective longitudinal dispersion coefficient. The range of the dispersion coefficient is rather broad at high water slack (HWS) and narrower at low water slack (LWS) because of the different tidal amplitudes. The spatially varying dispersion coefficient has maximal values (>300 m2 s?1) near the mouth at high water and decreases gradually upstream, with fluctuations. The temporally varying dispersion coefficient appears to be positively correlated with river discharges at both low and high tide. The dispersion varies with the square root of river discharges at HWS and LWS. The dispersive salt fluxes increases with increasing river discharges and decreases with decreasing river discharges at HWS and LWS. Estimation of the numerical values of the effective longitudinal dispersion coefficient in the SRE can be useful for better understanding of the distributions of other tracers in the SRE as well as for developing and testing hypotheses about various mixing mechanisms.

D. C. Shaha; Y.-K. Cho; M.-T. Kwak; S. R. Kundu; K. T. Jung

2011-01-01

220

Caspian Rapid Sea Level Changing Impact on Estuaries Morphodynamic Deformation  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper, the evaluation of sedimentary-morphodynamic deformation of main estuaries of rivers in the southern coasts of the Caspian Sea is main target. With selecting, eight main rivers and by sampling of sediments on them in the beach zones, geometry of surrounded beach structure, morphodynamic condition and sedimentary deposition processes were analyzed. with interpretation satellite and aerial images of study area along the period between 1983 till 2004 that correspond to last progression phase of Caspian sea level arise (+ 2.5m), the effect of rapid sea level changing of the Caspian Sea on beach and mouth of rivers have been measured. The results show that there are different type of the estuaries in the study area and the last sea level arise has caused morphdynamic deformation (trait inclination of rivers, inflation of mouth and it’s widen) on the beach zone and the rivers mouth condition. Therefore as conclusion, the rivers of the Caspian Sea southern coasts have different behavior against rapid sea level changing in the coastal zones and they are classified to three statements: erosion, accretion and transition.

Homayoun Khoshravan; Masoumeh Banihashemi

2013-01-01

 
 
 
 
221

Effects of Prevailing Winds on Turbidity of a Shallow Estuary  

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Full Text Available 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 responsible for the long-term, large-scale turbidity pattern of the estuary, whereas the short-term changes in wind direction had differential effects on turbidity and water level in varying locations. There were temporal and spatial changes in the relationship between vertical light attenuation coefficient (Kd) and turbidity, which indicate difference in phytoplankton and color also affect Kd. This study demonstrates that the effect of wind on turbidity and water level on different shores can be identified through system-specific analyses of turbidity patterns.

Hyun Jung Cho

2007-01-01

222

New distributed records of Bambusoideae (Poaceae) in Southwest, China  

UK PubMed Central (United Kingdom)

Three species and one cultivar of bamboo as the distributed new records in Southwest, China, were respectively reported on this paper. Among them, Dendrocalamus latiforus Munro cv. Mei-nung W.C. Lin was a new record to mainland China from Yunnan and Guizhou; The genera Drepanostachyum with species D. hirsutissimum W.D.Li et Y.C. Zhong was the new record to Guangxi; Bambusa tuldoides Munro was firstly discovered in Guangxi and Guizhou at the same time; Bambusa guangxiensis Chia et H.L. Fung was known firstly in Guizhou, too.

Du Fan

2001-01-01

223

Prevalence of trypanosomiasis in cattle in south-west Zambia.  

UK PubMed Central (United Kingdom)

A trypanosomiasis survey was conducted in South-West Zambia. From a total of 3,346 cattle sampled 342 cattle showed a positive trypanosomiasis parasitaemia. During the survey trypanosome species and PCV values were also recorded. With simple statistical analysis populations with higher and lower prevalence rates were differentiated. The results indicated that the Kwando River Basin Tsetse Fly Belt and the Kafue River Basin Tsetse Fly Belt infested a larger area than originally assumed and that a link-up between both belts occurred or will occur in the near future.

Corten JJ; ter Huurne AA; Moorhouse PD; de Rooij RC

1988-05-01

224

Gill asymmetry in Labeo ogunensis from Ogun river, Southwest Nigeria  

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Full Text Available Fluctuating asymmetry (FA), often used as indicator of environmental stress, was evaluated in gill rakers and filaments of Labeo ogunensis from Ogun river, Southwest Nigeria. Mean length and weight of 13.68+1.28 cm and 59.40+17.48 g were respectively recorded. The gill rakers (t = -0.919) and filaments (t = -1.150) from both sides were not significantly different. The gill filaments recorded (0.31+2.42) higher incidence of fluctuating asymmetry (FA) compared with the gill rakers (0.21+1.58), signifying developmental interference in the population. Fish size and sex were observed to exert minimal influence on FA

A.A. Ayoade; A.A. Sowunmi; H.I. Nwachukwu

2004-01-01

225

Health Care Services Used by Appalachians in Southwest Virginia  

Directory of Open Access Journals (Sweden)

Full Text Available The purpose of this research was to study the healthcare services used by Appalachians in southwest Virginia. The study finds that emergency room users are likely to be never married and male. On the other hand, those with a diagnosed medical condition are likely to choose a physician as their primary healthcare provider. The results underscore the critical role of insurance in health care. Individuals with no health coverage are more likely to use emergency room services. The study finds no difference in healthcare services in terms of private or public insurance. Both groups are equally likely to use a physician as their primary healthcare provider.

Marion R. Manton; Gwendolyn B. Thornton

2008-01-01

226

Comparing spatial and temporal dynamics of anammox and denitrifying communities at Cape Fear River Estuary and New River Estuary, North Carolina  

Science.gov (United States)

Anaerobic ammonium oxidation (anammox) and denitrification are two main microbial processes capable of removing fixed nitrogen by conversion into a gaseous species. Both microbial processes are known to occur in anoxic estuarine sediments and are capable of remediating excess nitrogen loadings from anthropogenic activities. In order to understand the importance of anammox and denitrification in estuarine ecosystems, we investigated both processes in two different estuaries of North Carolina to compare sedimentary nitrogen removal capacity and to identify key players of N2 production pathways. Both Cape Fear River Estuary (CFRE) and New River Estuary (NRE) are highly enriched with nitrogen from anthropogenic sources in spite of distinct geomorphological and geochemical characteristics. We conducted seasonal samplings to collect sediments across transects at fifteen stations along each estuary. 15N tracer techniques were used to measure spatial and temporal variations of N2 production by denitrification and anammox in estuarine sediments. Molecular analysis of nitrous oxide reductase (nosZ) and hydrazine oxidase (hzo) genes was conducted to examine community structures of denitrifying and anammox bacteria, respectively. Denitrification was found to be the dominant N2 production processes in both estuaries. Anammox contributed up to 19% and 15 % of total N2 productions in the CFEE and the NRE, respectively. Phylogenetic analysis of hzo genes identified that the anammox bacteria at both estuaries are closely associated with five known genera in the order Brocadiales. Anammox communities at the CFRE showed biogeographical distribution along the estuarine gradients while high seasonal variations were observed in the NRE communities. Spatial and temporal variations of denitrifying communities at both estuaries were also found based on nosZ gene analysis. Multivariate analysis was conducted to define key biogeochemical parameters influencing the community dynamics and activities of anammox and denitrifying bacteria in these ecosystems. Thus, this study reveals the importance of community structure to its function, as well as estimates and compares potential N removal capacity in two geologically distinct estuarine ecosystems.

Lisa, J. A.; Hirsch, M. D.; Duernberger, K. A.; Tobias, C. R.; Song, B.

2010-12-01

227

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

Energy Technology Data Exchange (ETDEWEB)

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).

Clark, N.A.; Kirby, J.S.; Langston, R.H.W.; Donald, P.; Mawdesley, T.; Evans, J.

1990-12-01

228

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

Energy Technology Data Exchange (ETDEWEB)

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).

Davenport, T.; Jeffers, J.N.R.; North, P.M. [Kent Univ., Canterbury (United Kingdom); Clark, N.A.; Langston, R.H.W.; Prys-Jones, R.P.

1990-12-31

229

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)

1990-01-01

230

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

2006-01-01

231

78 FR 43964 - Intent To Prepare a Supplemental Draft Environmental Impact Statement for the Southwest Light...  

Science.gov (United States)

...Environmental Impact Statement for the Southwest Light Rail Transit Extension Project (Formerly...Impact Statement (SDEIS) for the Southwest Light Rail Transit Extension (SWLRT) Project...2012. The Project is a new 15.8-mile light rail alignment with 17 new light rail...

2013-07-22

232

Investigating turkey (Meleagris gallopavo) domestication in the Southwest United States through ancient DNA analysis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 rema...

Speller, Camilla Filomena

233

Total Environmental Action, Inc. Final Report: Design and Fabrication of a Prototype System for Photovoltaic Residences in the Southwest.  

Science.gov (United States)

Described are the design of a photovoltaic-powered residence for the American Southwest, dubbed Casa fotovoltaica, and the construction of a prototype building at the Southwest Residential Experiment Station (SWRES) for testing the performance of the full...

1982-01-01

234

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

International Nuclear Information System (INIS)

To determine the origin of sediments in the Savannah River estuary, we have measured 137Cs and stable isotope ratios of C, N and S in suspended particles and bottom sediments at several sites in the Savannah River and estuary and offshore on the continental shelf. The 137Cs and stable isotope data were used with a two-endmember mixing model to partition the suspended and bottom sediments at sites along a salinity gradient into riverine and marine fractions. Results from the 137Cs measurements indicated that ? 65% of inorganic sediments in suspension or in the top 5 cm of bottom deposits in the estuary were of marine origin. Stable carbon isotope ratios indicated that ?74% of the organic sediments in suspension or on the bottom of the estuary were of marine origin, except for sediments at the lowest salinity estuarine site (

1992-01-01

235

Organic Environmental Chemicals in German Estuaries - Occurrence, Biotransfer and Degradation. Final Report.  

Science.gov (United States)

A variety of organic environmental chemicals has been identified in water, sediments and organisms in the estuaries of rivers Elbe, Weser, Ems and in adjacent coastal waters. PCB and octachlorostyrene were the predominant compounds in fish livers. Elevate...

W. Ernst G. Eder H. Goerke K. Weber S. Weigelt

1986-01-01

236

Seasonal and spatial distributions of tributyltin in surface sediment of the Tolka Estuary, Dublin, Ireland.  

Science.gov (United States)

Aquatic pollution by tributyltin (TBT) is of concern because of its high toxicity to marine life. TBT loadings of estuarine sediments may remain elevated because of long flushing times in estuaries due to their enclosed physicality. The Tolka Estuary, Co. Dublin, Ireland, is a typical Irish urban estuary. It has a significant pollution loading. The results of 12 months' analysis of TBT spatial and temporal distributions in this estuary are presented in this paper. Data from a total of 10 sample points are presented. The concentrations of TBT in the sediment were analysed using differential pulse polarography. Significant seasonal and spatial trends in TBT distribution were observed over the 12-month period. TBT concentrations ranged from 0.1 ppb in winter to 8.6 ppb in summer with a 1.5 ppb average. Organic matter (OM) concentrations of sediment exhibited similar seasonal trends and a positive correlation between OM and TBT distributions was observed. PMID:16480800

Buggy, Conor J; Tobin, John M

2006-02-15

237

Zooplankton, Water Temperature, and Salinities in the Columbia River Estuary, December 1971 through December 1972.  

Science.gov (United States)

Sampling was conducted at seven stations in the Columbia River estuary throughout 1972 to provide baseline information on species diversity, relative abundance, and seasonal occurrence of zooplankton, as well as ambient water temperatures and salinities. ...

D. A. Misitano

1974-01-01

238

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

Science.gov (United States)

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

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

2005-01-01

239

Application of Nuclear Analytical Methods to Heavy Metal Pollution Studies of Estuaries.  

Science.gov (United States)

Important objectives of heavy metal pollution studies of estuaries are the understanding of the transport phenomena in these complex ecosystems and the discovery of the pollution history and the geochemical background. Such studies require high precision ...

B. Anders W. Junge J. Knoth W. Michaelis R. Pepelnik

1984-01-01

240

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

Science.gov (United States)

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

 
 
 
 
241

75 FR 2517 - Notice of Solicitation for Estuary Habitat Restoration Program  

Science.gov (United States)

...for estuary habitat restoration projects. The Council requests that all proposals address the potential effects of sea level change and other impacts related to climate change on the viability of the proposed restoration. This may take the...

2010-01-15

242

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...

243

EFFECTS OF FRESHWATER RELEASES AND SEASON ON OYSTERS (CRASSOSTREA VIRGINICA) IN CALOOSAHATCHEE ESTUARY, FLORIDA  

Science.gov (United States)

The influence of freshwater releases and season on disease prevalence and intensity of Perkinsus marinus, condition index, gonadal condition, recruitment potential, and growth of oysters was examined monthly at five locations along the Caloosahatchee estuary, Florida. Temperature...

244

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

Science.gov (United States)

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

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

2013-06-19

245

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

UK PubMed Central (United Kingdom)

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

Smalling KL; Kuivila KM; Orlando JL; Phillips BM; Anderson BS; Siegler K; Hunt JW; Hamilton M

2013-08-01

246

The Rising Tide of Estuary English: The Changing Nature of Oral British Business Communication.  

Science.gov (United States)

|Defines "Estuary English," a fast-growing accent of British English that is spreading across England. Discusses its usage in the British business community; its acceptability and future; and its implications for business communicators, teachers, and consultants. (SR)|

Scott, James Calvert

1995-01-01

247

Factors governing the pH in a heterotrophic, turbid, tidal estuary  

Directory of Open Access Journals (Sweden)

Full Text Available A method to quantify the influence of kinetically modelled biogeochemical processes on the pH of an ecosystem with time variable acid-base dissociation constants is presented and applied to the heterotrophic, turbid Scheldt estuary (SW Netherlands, N Belgium). Nitrification is identified as the main process governing the pH profile of this estuary, while CO2 degassing and advective-dispersive transport "buffer" the effect of nitrification. CO2 degassing accounts for the largest proton turnover per year in the whole estuary. There is a clear inverse correlation between oxygen turnover and proton turnover. The main driver of long-term changes in the mean estuarine pH from 2001 to 2004 is a changing freshwater flow which influences the pH "directly" via [?CO2] and [TA] and to a significant amount also "indirectly" via [?NH4+] and the nitrification rates in the estuary.

A. F. Hofmann; F. J. R. Meysman; K. Soetaert; J. J. Middelburg

2009-01-01

248

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

Directory of Open Access Journals (Sweden)

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

Nandadeep U. Fal Dessai

2013-01-01

249

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

Science.gov (United States)

...Mammals Incidental to Specified Activities; Russian River Estuary Management Activities AGENCY...activities conducted at the mouth of the Russian River, Sonoma County, California. DATES...Biological Opinion (2008) on the effects of Russian River management activities on...

2013-04-22

250

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

Science.gov (United States)

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

251

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

Science.gov (United States)

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

252

Contemporary hydrodynamics and morphological change of a microtidal estuary: a numerical modelling study  

Science.gov (United States)

Contemporary hydrodynamics and morphological change are examined in a shallow microtidal estuary, located on a wave-dominated coast (Port Stephens, NSW, Australia). Process-based numerical modelling is undertaken by combining modules for hydrodynamics, waves, sediment transport and bathymetry updates. Model results suggest that the complex estuarine bathymetry and geometry give rise to spatial variations in the tidal currents and a marked asymmetry between ebb and flood flows. Sediment transport paths correspond with tidal asymmetry patterns. The SE storms significantly enhance the quantities of sediment transport, while locally generated waves by the westerly strong winds also are capable of causing sediment entrainment and contribute to the delta morphological change. The wave/wind-induced currents are not uniform with flow over shoals driven in the same direction as waves/winds while a reverse flow occurring in the adjacent channel. The conceptual sediment transport model developed in this study shows flood-directed transport occurs on the flood ramp while ebb-directed net transport occurs in the tidal channels and at the estuary entrance. Accretion of the intertidal sand shoals and deepening of tidal channels, as revealed by the model, suggest that sediment-infilling becomes advanced, which may lead to an ebb-dominated estuary. It is likely that a switch from flood- to ebb-dominance occurs during the estuary evolution, and the present-day estuary acts as a sediment source rather than sediment sink to the coastal system. This is conflictive to the expectation drawn from the estuarine morphology; however, it is consistent with previous research suggesting that, in an infilling estuary, an increase in build-up of intertidal flats/shoals can eventually shift an estuary towards ebb dominance. Thus, field data are needed to validate the result presented here, and further study is required to investigate a variety of estuaries in the Australian area.

Jiang, Angela Wenping; Ranasinghe, Roshanka; Cowell, Peter

2013-01-01

253

Ecosystem Services Transcend Boundaries: Estuaries Provide Resource Subsidies and Influence Functional Diversity in Coastal Benthic Communities  

Science.gov (United States)

Background Estuaries are highly productive ecosystems that can export organic matter to coastal seas (the ‘outwelling hypothesis’). However the role of this food resource subsidy on coastal ecosystem functioning has not been examined. Methodology/Principal Findings We investigated the influence of estuarine primary production as a resource subsidy and the influence of estuaries on biodiversity and ecosystem functioning in coastal mollusk-dominated sediment communities. Stable isotope values (?13C, ?15N) demonstrated that estuarine primary production was exported to the adjacent coast and contributed to secondary production up to 4 km from the estuary mouth. Further, isotope signatures of suspension feeding bivalves on the adjacent coast (Dosinia subrosea) closely mirrored the isotope values of the dominant bivalves inside the estuaries (Austrovenus stutchburyi), indicating utilization of similar organic matter sources. However, the food subsidies varied between estuaries; with estuarine suspended particulate organic matter (SPOM) dominant at Tairua estuary, while seagrass and fringing vegetation detritus was proportionately more important at Whangapoua estuary, with lesser contributions of estuarine SPOM. Distance from the estuary mouth and the size and density of large bivalves (Dosinia spp.) had a significant influence on the composition of biological traits in the coastal macrobenthic communities, signaling the potential influence of these spatial subsidies on ecosystem functioning. Conclusions/Significance Our study demonstrated that the locations where ecosystem services like productivity are generated are not necessarily where the services are utilized. Further, we identified indirect positive effects of the nutrient subsidies on biodiversity (the estuarine subsidies influenced the bivalves, which in turn affected the diversity and functional trait composition of the coastal sediment macrofaunal communities). These findings highlight the importance of integrative ecosystem-based management that maintains the connectivity of estuarine and coastal ecosystems.

Savage, Candida; Thrush, Simon F.; Lohrer, Andrew M.; Hewitt, Judi E.

2012-01-01

254

Heavy metal anomalies in the Tinto and Odiel river and estuary system, Spain  

Energy Technology Data Exchange (ETDEWEB)

The Tinto and Odiel river drain 100 km from the Rio Tinto sulphide mining district and join at a 20-km estuary entering the Atlantic Ocean. A reconnaissance study of heavy metal anomalies in channel sand and overbank mud of the river and estuary shows the following upstream to downstream ranges in ppm ([mu]g g[sup [minus]1]): As 3,000 to <200, Cd 30 to <0.1, Cu 1,500 to 10, Pb 2,000 to <10, Sb 300 to <150, and Zn 3,000 to <200. Organic-rich sandy-silty overbank clay has been analyzed to represent suspended load materials. The high content of 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 river bed sand has been analyzed to represent bedload transport of naturally-occurring sulfide minerals. The sand has high concentrations of metals upstream, decreasing by 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. 36 refs., 8 figs., 4 tabs.

Nelson, C.H.; Lamothe, P.J. (Geological Survey, Menlo Park, CA (United States))

1993-12-01

255

Ecosystem services transcend boundaries: estuaries provide resource subsidies and influence functional diversity in coastal benthic communities.  

UK PubMed Central (United Kingdom)

BACKGROUND: Estuaries are highly productive ecosystems that can export organic matter to coastal seas (the 'outwelling hypothesis'). However the role of this food resource subsidy on coastal ecosystem functioning has not been examined. METHODOLOGY/PRINCIPAL FINDINGS: We investigated the influence of estuarine primary production as a resource subsidy and the influence of estuaries on biodiversity and ecosystem functioning in coastal mollusk-dominated sediment communities. Stable isotope values (?(13)C, ?(15)N) demonstrated that estuarine primary production was exported to the adjacent coast and contributed to secondary production up to 4 km from the estuary mouth. Further, isotope signatures of suspension feeding bivalves on the adjacent coast (Dosinia subrosea) closely mirrored the isotope values of the dominant bivalves inside the estuaries (Austrovenus stutchburyi), indicating utilization of similar organic matter sources. However, the food subsidies varied between estuaries; with estuarine suspended particulate organic matter (SPOM) dominant at Tairua estuary, while seagrass and fringing vegetation detritus was proportionately more important at Whangapoua estuary, with lesser contributions of estuarine SPOM. Distance from the estuary mouth and the size and density of large bivalves (Dosinia spp.) had a significant influence on the composition of biological traits in the coastal macrobenthic communities, signaling the potential influence of these spatial subsidies on ecosystem functioning. CONCLUSIONS/SIGNIFICANCE: Our study demonstrated that the locations where ecosystem services like productivity are generated are not necessarily where the services are utilized. Further, we identified indirect positive effects of the nutrient subsidies on biodiversity (the estuarine subsidies influenced the bivalves, which in turn affected the diversity and functional trait composition of the coastal sediment macrofaunal communities). These findings highlight the importance of integrative ecosystem-based management that maintains the connectivity of estuarine and coastal ecosystems.

Savage C; Thrush SF; Lohrer AM; Hewitt JE

2012-01-01

256

Site-specific probabilistic ecological risk assessment of a volatile chlorinated hydrocarbon-contaminated tidal estuary.  

UK PubMed Central (United Kingdom)

Groundwater contaminated with volatile chlorinated hydrocarbons (VCHs) was identified as discharging to Penrhyn Estuary, an intertidal embayment of Botany Bay, New South Wales, Australia. A screening-level hazard assessment of surface water in Penrhyn Estuary identified an unacceptable hazard to marine organisms posed by VCHs. Given the limitations of hazard assessments, the present study conducted a higher-tier, quantitative probabilistic risk assessment using the joint probability curve (JPC) method that accounted for variability in exposure and toxicity profiles to quantify risk (delta). Risk was assessed for 24 scenarios, including four areas of the estuary based on three exposure scenarios (low tide, high tide, and both low and high tides) and two toxicity scenarios (chronic no-observed-effect concentrations [NOEC] and 50% effect concentrations [EC50]). Risk (delta) was greater at low tide than at high tide and varied throughout the tidal cycle. Spatial distributions of risk in the estuary were similar using both NOEC and EC50 data. The exposure scenario including data combined from both tides was considered the most accurate representation of the ecological risk in the estuary. When assessing risk using data across both tides, the greatest risk was identified in the Springvale tributary (delta=25%)-closest to the source area-followed by the inner estuary (delta=4%) and the Floodvale tributary (delta=2%), with the lowest risk in the outer estuary (delta=0.1%), farthest from the source area. Going from the screening level ecological risk assessment (ERA) to the probabilistic ERA changed the risk from unacceptable to acceptable in 50% of exposure scenarios in two of the four areas within the estuary. The probabilistic ERA provided a more realistic assessment of risk than the screening-level hazard assessment.

Hunt J; Birch G; Warne MS

2010-05-01

257

MCTTFA applied to differential biomonitoring in Sado estuary region  

International Nuclear Information System (INIS)

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

2004-01-01

258

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

1987-01-01

259

Fundamental research on estuaries: The importance of an interdisciplinary approach  

Energy Technology Data Exchange (ETDEWEB)

In 1974 the Geophysics Research Board completed a plan, for a series of studies to be carried out on various subjects related to geophysics. One purpose of the studies is to provide assessments from the scientific community to aid policymakers in decisions on societal problems that involve geophysics. An important part of such an assessment is an evaluation of the adequacy of present geophysical knowledge and the appropriateness of present research programs to provide information required for those decisions. This study examines the need for basic research to understand estuarine processes. The major unanswered questions relate to the interrelationships of estuarine circulation, biota, geology, and chemistry, where an interdisciplinary coordinated effort will be necessary. The areas were organized around a traditional disciplinary facet of estuaries but focused on the interdisciplinary needs. 58 refs., 11 figs., 1 tab.

1983-01-01

260

Comprehensive analysis of an ecological risk assessment of the Daliao River estuary, China.  

UK PubMed Central (United Kingdom)

At present, most estuarine ecological risk studies are based on terrestrial ecosystem models, which ignore spatial heterogeneity. The Daliao River estuary has representative characteristics of many estuaries in China, and we used this estuary as the study area to formulate an estuarine ecological risk evaluation model. Targeting the estuary's special hydrodynamic condition, this model incorporated variables that were under the influence of human activities and used them as the major factors for partitioning sections of the river according to risk values. It also explored the spatial and temporal distribution laws of estuarine ecological risk. The results showed that, on the whole, the ecological risk of the Daliao River estuary area was relatively high. At a temporal level, runoff was the main factor resulting in differences in ecological risk, while at the spatial level, the ecological risk index was affected by pollutants carried by runoff from upstream, as well as downstream pollution emissions and dilution by seawater at the mouth of the sea. The characteristics of this model make it possible to simulate the spatial and temporal risk distribution in different regions and under different rainfall regimes. This model can thus be applied in other estuarine areas and provides some technical support for analysis and control of ecological destruction in estuary areas.

Yu G; Chen J; Zhang X; Li Z

2013-08-01

 
 
 
 
261

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

UK PubMed Central (United Kingdom)

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.

Vincent-Hubert F; Heas-Moisan K; Munschy C; Tronczynski J

2012-01-01

262

Spawning of riverbream, Acanthopagrus berda, in Kosi estuary  

Directory of Open Access Journals (Sweden)

Full Text Available ENGLISH ABSTRACT: The spawning habits of Acanthopagrus berda, an estuary-dependent seabream (Family Sparidae), are investigated. Spawning takes place in the Kosi estuary at night and eggs are transported out to sea during peak ebb tides. There is a preponderance of males in the spawning aggregation (sex ratio - 8,8 : 1 m/f) and indirect evidence suggests that males and females are continually recruiting to the aggregation, spawning, and moving back up into the lakes so that there are no more than 2000 individuals at the mouth at any one time. Sexed fish were tagged in an effort to produce evidence of protandrous sex change in this species. It is noted that the degradation of estuarine habitats could have serious effects on an estuarine-dependent species which has developed a spawning strategy of this nature. ********* AFRIKAANSE OPSOMMING: Die broeigewoontes van Acanthopagrus berda, 'n riviermond-afhanklike seebras (Familie Sparidae) is nagevors. In die Kosi tregtermonding vind kuitskiet in die nag plaas en die eiers word gedurende piek ebgetye na die see weggevoer. By die broeisameloop is daar oorwegend mannetjies (geslagsverhouding -8,8 : 1 m/f) en onregstreekse bewyse toon dat mannetjies en wyfies voortdurend by die sameloop aansluit, broei en dan na die mere terugbeweeg, sodat op 'n gegewe tyd daar nooit meer as 2000 individue by die tregtermond voorkom nie. Visse waarvan die geslag bepaal is, is gemerk in 'n poging om bewyse van protandriese geslagsverandering by die spesie te vind. Daar word kennis geneem dat die agteruitgang van die tregtermondhabitatte 'n ernstige uitwerking sal hê op riviermond-afhanklike spesies wat 'n broeistrategie van die aard ontwikkel het.

P.A. Garratt

2012-01-01

263

Gravity and magnetic data of Midway Valley, southwest Nevada  

Energy Technology Data Exchange (ETDEWEB)

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.

Ponce, D.A.; Langenheim, V.E.; Sikora, R.F. [Geological Survey, Menlo Park, CA (United States)

1993-12-31

264

Gravity and magnetic study of Yucca Wash, southwest Nevada  

Energy Technology Data Exchange (ETDEWEB)

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/cm{sup 3} 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/cm{sup 3}.

Langenheim, V.E.; Ponce, D.A.; Oliver, H.W.; Sikora, R.F. [Geological Survey, Menlo Park, CA (United States)

1993-12-31

265

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.

1993-01-01

266

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.

1993-01-01

267

Wolf predation in the Burwash caribou herd, southwest Yukon  

Directory of Open Access Journals (Sweden)

Full Text Available The role of wolf predation as a proximate mortality factor influencing caribou herd growth was assessed in the Burwash herd (400 animals) in the southwest Yukon between 1980 - 1982. Ten to 14 wolves in two packs preyed primarily on caribou (Rangifer tarandus caribou) and moose (Alces alces) with disproportionate consumption of caribou (relative to available biomass) in the rut and winter periods. Wolf predation was responsible for 72% of total annual mortality in 1980 - 1981 and 46% in 1981 - 1982. Losses due to human harvest varied between 7 to 13%. Additional limited data on climatic factors and winter forage indicated forage-climate were not major proximate mortality factors in 1980 - 1981, but that early-calving climate may have been a factor in increased calf mortality in 1982.

David A. Gauthier; John B. Theberge

1986-01-01

268

Uncertainty quantification of US Southwest climate from IPCC projections.  

Energy Technology Data Exchange (ETDEWEB)

The Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4) made extensive use of coordinated simulations by 18 international modeling groups using a variety of coupled general circulation models (GCMs) with different numerics, algorithms, resolutions, physics models, and parameterizations. These simulations span the 20th century and provide forecasts for various carbon emissions scenarios in the 21st century. All the output from this panoply of models is made available to researchers on an archive maintained by the Program for Climate Model Diagnosis and Intercomparison (PCMDI) at LLNL. I have downloaded this data and completed the first steps toward a statistical analysis of these ensembles for the US Southwest. This constitutes the final report for a late start LDRD project. Complete analysis will be the subject of a forthcoming report.

Boslough, Mark Bruce Elrick

2011-01-01

269

HIV testing behaviors among female sex workers in Southwest China.  

UK PubMed Central (United Kingdom)

Despite the recognized importance of HIV testing in prevention, care and treatment, HIV testing remains low in China. Millions of female sex workers (FSW) play a critical role in China's escalating HIV epidemic. Limited data are available regarding HIV testing behavior among this at-risk population. This study, based on a cross-sectional survey of 1,022 FSW recruited from communities in Southwest China, attempted to address the literature gap. Our data revealed that 48% of FSW ever took HIV testing; older age, less education, working in higher-income commercial sex venues and better HIV knowledge were associated with HIV testing. Those who never took HIV testing were more likely to engage in high-risk behaviors including inconsistent condom use with clients and stable partners. A number of psychological and structural barriers to testing were also reported. We call for culturally appropriate interventions to reduce HIV risks and promote HIV testing for vulnerable FSW in China.

Hong Y; Zhang C; Li X; Fang X; Lin X; Zhou Y; Liu W

2012-01-01

270

Historical perspective of lubricant deposit evaluations at Southwest Research Institute  

Energy Technology Data Exchange (ETDEWEB)

This paper presents numerous bench tests investigated at Southwest Research Institute which were intended to evaluate the performance of automotive engine and gear oils, and aircraft turbine lubricants. In most cases the tests were designed to simulate certain aspects of the environment seen by the lubricant while performing its function, and lubricant degradation with subsequent deposit formation are the parameters measured. Although in many instances good correlation with specific engine tests were achieved, the final measure of acceptability of a finished lubricant for military applications remains the full engine tests for engine oils; automotive gear tests for gear oils, and full-scale turbine engine tests for the aircraft lubricants. The tests discussed here are excellent screening devices for new experimental lubricant formulations.

Bowden, J.N.; Lestz, S.J.

1980-11-01

271

Reservoir characterization of the Smackover Formation in southwest Alabama  

Energy Technology Data Exchange (ETDEWEB)

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.

Kopaska-Merkel, D.C.; Hall, D.R.; Mann, S.D.; Tew, B.H.

1993-02-01

272

Bisantrene hydrochloride in gastric adenocarcinoma: a Southwest Oncology Group Study.  

Science.gov (United States)

Because "the standard" chemotherapy for advanced gastric adenocarcinoma, the FAM combination of 5-fluorouracil, adriamycin, and mitomycin, is only minimally effective, there is a clear need for other choices. Therefore, the Southwest Oncology Group tested the new adriamycin analog, bisantrene, hoping that it might be more effective than the "parent drug." Twenty-six patients with gastric adenocarcinoma were treated on a program of every-3-week 2-hour bisantrene infusions. The starting dose was 260 mg/m2 (208 if poor risk), with subsequent doses based on prior toxicity. The regimen caused sufficient toxicity (especially local phlebitis with pain and swelling) to assure an adequate test. One person (3.8% of eligible patients) experienced a clinically useful 3-month response. He had previously had progressive disease on FAM. Nevertheless, we conclude that bisantrene is not an addition to the small list of drugs useful in the management of gastric adenocarcinoma. PMID:3713640

Panettiere, F J; Jones, S E; Oishi, N; Eyre, H J; O'Bryan, R M; Andes, W A; Taylor, S A; Grozea, P N

1986-01-01

273

Copper smelters and atmospheric visibility in the southwest, seasonal analysis  

Energy Technology Data Exchange (ETDEWEB)

This paper presents the results of the seasonal analysis from a study which has evaluated the effects of copper smelter emissions on atmospheric visibility in southwestern national parks and wilderness areas. The study also examined these effects on an episodic basis and conducted statistical analyses of aerosol and visibility measurement data before and during the summer 1980 copper strike. Copper smelters have been the major emitters of sulfur oxides (SO/sub x/) in the Southwest. The contribution of the copper smelters to visibility reduction versus all other contributions, natural as well as anthropogenic, is estimated at selected locations. This study was initiated to evaluate the effectiveness of the constant emission control (CEC) strategy in improving visibility at southwestern national parks and wilderness areas. The southwestern states of Arizona, Nevada, New Mexico, and Utah are implementing the CEC strategy to control SO/sub x/ emissions from copper smelters as part of their state implementation plans (SIP).

Nochumson, D.H.; Williams, M.D.

1983-01-01

274

Radionuclide transfer from Sellafield to south-west Scotland  

International Nuclear Information System (INIS)

A transect of surface marine sediment was collected off and between Sellafield and Kirkcudbright Bay in south-west Scotland. The results indicate that anthropogenic radionuclide activity concentrations are variable primarily as a function of sediment type or particle size distribution and are independent of distance from source. This fact, together with relative uniformity of radionuclide activity quotients and chemical associations, clearly demonstrates direct physical migration of particle-associated activity from the point of discharge off the Cumbrian coast to the north Solway coast. Relative constancy of 241Am/241Pu activity quotients suggests that this transport process is rapid, occurring on a timescale of years rather than decades. In summary, dissolved nuclide transport of actinides is of secondary importance in this region. (author)

1990-01-01

275

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

International Nuclear Information System (INIS)

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

276

Influence of bathymetry on hydrography and circulation at the region between an estuary mouth and the adjacent continental shelf  

Science.gov (United States)

Bathymetry effects on the flow field at the transition between idealized estuaries and the adjacent ocean are studied with the Regional Ocean Modeling System (ROMS). Estuary width, depth, and channel direction at the shelf are used to determine flow characteristics in and out of an idealized estuary. The idealized estuary connects to an upstream boundary, where freshwater discharges, and an offshore tidal boundary. Tidally averaged salinity and flow structures are examined at the estuary mouth. A recirculation feature directly affects flow at the estuary mouth, especially in shallow and wide estuarine systems. The recirculation retards the exchange flow near the edges of the estuary mouth and consequently allows strengthening of the flow in the middle. The geometric shape of the estuarine channel affects the strength of the residual flow at the estuary mouth. The presence of an extended submarine channel on the shelf enhances the baroclinic circulation and stratification, and maximizes the salinity intrusion length without additional external forces. The direction of this submarine channel affects the exchange flow structures at the estuary/ocean transition zone in such a way that the salinity intrusion length increases with a left-turning channel (in the Kelvin wave sense of the fresh water flow direction). This is attributed to the competition between centrifugal and Coriolis forces. Flow characteristics described by the Kelvin and Ekman number, which outline channel geometric effects, are similar to previous studies.

Lee, Jungwoo; Valle-Levinson, Arnoldo

2012-06-01

277

Decay of eddies at the South-West Indian Ridge  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english The South-West Indian Ridge in the Indian sector of the Southern Ocean is a region recognised for the creation of particularly intense eddy disturbances in the mean flow of the Antarctic Circumpolar Current. Eddies formed at this ridge have been extensively studied over the past decade using hydrographic, satellite, drifter and float data and it is hypothesised that they could provide a vehicle for localised meridional heat and salt exchange. The effectiveness of this pro (more) cess 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.

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

2011-01-01

278

Decay of eddies at the South-West Indian Ridge  

Directory of Open Access Journals (Sweden)

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

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

2011-01-01

279

A lightning climatology of the South-West Indian Ocean  

Directory of Open Access Journals (Sweden)

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.

C. Bovalo; C. Barthe; N. Bègue

2012-01-01

280

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

UK PubMed Central (United Kingdom)

Four hundred twenty three marine mammals, in 72 stranding events, were recorded between 1877 and 2005 in New Caledonia, the Loyalty Islands, and Vanuatu in the southwest Pacific. Sixteen species were represented in this count, including: minke whale, Balaenoptera acutorostrata (1 single stranding), sei whale, B. borealis (1 single stranding), blue whale, B. musculus (1 single stranding), humpback whale, Megaptera novaeangliae (2 single strandings), giant sperm whale, Physeter macrocephalus (18 single strandings, 2 pair strandings), pygmy sperm whale, Kogia breviceps (5 single strandings), dwarf sperm whale, K. sima (2 single strandings, 1 triple stranding), Blainville's beaked whale, Mesoplodon densirostris (2 single strandings), short-finned pilot whale, Globicephala macrorhynchus (4 strandings, 56 individuals), melon-headed whale, Peponocephala electra (1 single stranding and 2 mass strandings totalling 231 individuals), common dolphin, Delphinus delphis (1 single stranding), spinner dolphin, Stenella longirostris (1 pair stranding and 2 mass strandings of groups of approximately 30 individuals each), Indian Ocean bottlenose dolphin, Tursiops aduncus (2 single strandings), dugong, Dugong dugon (14 single strandings), and New Zealand fur seal, Arctocephalus forsteri (3 single strandings). A stranded rorqual identified as an Antarctic minke whale (B. bonaerensis), with coloration patterns that did not match known descriptions, was also reported. Sei whale was recorded for the first time in the tropical Southwest Pacific region and Antarctic minke whale, melon-headed whale, and Indian Ocean bottlenose dolphin were recorded for the first time in New Caledonia. Strandings of sperm whales were most frequent in the spring, but also occurred in autumn months, suggesting a seasonal pattern of occurrence possibly related to seasonal migration. One stranded humpback whale bore the scars of a killer whale's attack and one dugong was injured by a shark. Scars left by propellers were noted on several stranded animals including one Antarctic minke whale, one pygmy sperm whale, one dwarf sperm whale, and four dugongs. Collisions with vessels were suspected to be a frequent cause of death for dugong.

Borsa P

2006-04-01

 
 
 
 
281

Hepatitis E Virus Seroprevalence among Blood Donors in Southwest Switzerland  

Science.gov (United States)

Aim The aim of this study was to determine the seroprevalence of Hepatitis E virus (HEV) among blood donors in southwest Switzerland. Background HEV is recognized as a food-borne disease in industrialized countries, transmitted mainly through pork meat. Cases of transmission through blood transfusion have also been reported. Recent studies have revealed seroprevalence rates of 13.5%, 16.6% and 20.6% among blood donors in England, France and Denmark, respectively. Methods We analyzed 550 consecutive blood donor samples collected in the region of Lausanne, canton of Vaud, Switzerland, for the presence of anti-HEV IgG, using the MP Diagnostics HEV ELISA kit. For each donor, we documented age, sex and alanine aminotransferase (ALT) value. Results The study panel was composed of 332 men (60.4%) and 218 women (39.6%). Overall, anti-HEV IgG was found in 27 of 550 samples (4.9%). The seroprevalence was 5.4% (18/332) in men and 4.1% (9/218) in women. The presence of anti-HEV IgG was not correlated with age, gender or ALT values. However, we observed a peak in seroprevalence of 5.3% in individuals aged 51 to 70 years old. Conclusions Compared with other European countries, HEV seroprevalence among blood donors in southwest Switzerland is low. The low seroprevalence may be explained by the sensitivity of commercial tests used and/or the strict regulation of animal and meat imports. Data regarding HEV prevalence in Swiss livestock are lacking and merit exploration.

Kaufmann, Annatina; Kenfak-Foguena, Alain; Andre, Cyril; Canellini, Giorgia; Burgisser, Philippe; Moradpour, Darius; Darling, Katharine E. A.; Cavassini, Matthias

2011-01-01

282

Southwest Center for Environmental Excellence and Opportunity Year End Report (Final Deliverable)  

Energy Technology Data Exchange (ETDEWEB)

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.

None

1998-11-09

283

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-05-15

284

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)

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.

Steven M. Wu

2012-01-01

285

BEHAVIOUR OF WATER QUALITY PARAMETERS DURING EBB TIDE IN DUNGUN RIVER ESTUARY, TERENGGANU.  

Directory of Open Access Journals (Sweden)

Full Text Available A study has been carried out to determine the behaviour of selected water quality (WQ) parameters in Dungun river estuary. Samplings were carried out twice during October 2001 under similar tidal conditions (ebb tide) whereby samples were collected as a function of salinity i.e. along the salinity gradients from 0 ppt (freshwater end-member) to 31 ppt (coastal water end-member). WQ parameters monitored were the general physical parameters (viz. temperature, pH, dissolved oxygen, suspended solids and redox potential), dissolved metals (copper, cadmium and lead), dissolved nutrients (nitrogen- and phosphate-based nutrients) and chlorophyll-a. The physical water quality parameters were measured in situ using a multi-parameter data logger whilst nutrients and chlorophyll-a analyses were carried out based on the colorimetric method. Dissolved metals were analysed using GF-AAS technique following the pre-concentration step using APDC-MIBK method. Results in general indicated that most of the parameters measured appear to behave non-conservatively with salinity. In the case of nutrients, with the exception of nitrate which exhibited removal behaviour, all other nitrogen- and phosphorus-based nutrients, exhibited addition behaviour in the estuary. Cadmium and lead were also found to behave in a non-conservative manner in the estuary i.e. positive deviation was observed for cadmium whilst lead exhibited a negative deviation from the theoretical dilution line. These observations suggest that the estuary act as a source for cadmium but a sink for lead. Copper on the hand exhibited a linear relationship with salinity indicating a conservative distribution along the estuary. Results obtained in the present study clearly show the different behaviour of a given water quality parameter in the estuary and also illustrate the important role played by Dungun River estuary in modifying the nutrient and metal concentrations during the transportation from the river to the coastal waters.

Norhayati Mohd Tahir1*, Suhaimi Suratman1, Noor Azhar Mohd Shazili2, Marinah Mohd Ariffin1, Mohd Shafaril Mohd Amin1, Nik Faris Malik Nik Iskandar Ariff1, Wan Nor Hasmizan Wan Sulaiman1

2008-01-01

286

Polychaete richness and abundance enhanced in anthropogenically modified estuaries despite high concentrations of toxic contaminants.  

UK PubMed Central (United Kingdom)

Ecological communities are increasingly exposed to multiple chemical and physical stressors, but distinguishing anthropogenic impacts from other environmental drivers remains challenging. Rarely are multiple stressors investigated in replicated studies over large spatial scales (>1000 kms) or supported with manipulations that are necessary to interpret ecological patterns. We measured the composition of sediment infaunal communities in relation to anthropogenic and natural stressors at multiple sites within seven estuaries. We observed increases in the richness and abundance of polychaete worms in heavily modified estuaries with severe metal contamination, but no changes in the diversity or abundance of other taxa. Estuaries in which toxic contaminants were elevated also showed evidence of organic enrichment. We hypothesised that the observed response of polychaetes was not a 'positive' response to toxic contamination or a reduction in biotic competition, but due to high levels of nutrients in heavily modified estuaries driving productivity in the water column and enriching the sediment over large spatial scales. We deployed defaunated field-collected sediments from the surveyed estuaries in a small scale experiment, but observed no effects of sediment characteristics (toxic or enriching). Furthermore, invertebrate recruitment instead reflected the low diversity and abundance observed during field surveys of this relatively 'pristine' estuary. This suggests that differences observed in the survey are not a direct consequence of sediment characteristics (even severe metal contamination) but are related to parameters that covary with estuary modification such as enhanced productivity from nutrient inputs and the diversity of the local species pool. This has implications for the interpretation of diversity measures in large-scale monitoring studies in which the observed patterns may be strongly influenced by many factors that covary with anthropogenic modification.

Dafforn KA; Kelaher BP; Simpson SL; Coleman MA; Hutchings PA; Clark GF; Knott NA; Doblin MA; Johnston EL

2013-01-01

287

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

DEFF Research Database (Denmark)

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.

Markager, Stiig; Stedmon, Colin

2011-01-01

288

Ecological characteristics of macrozoobenthic community of tidal flat wetland in the changjiang estuary  

UK PubMed Central (United Kingdom)

The species composition and community characteristics of macro zoobenthos in the tidal flat wetland of the Changjiang estuary were investigated. There are 68 species of benthic macro-invertebrates on the tidal flat wetland of the estuary. They can be divided into three categories, i.e, fresh water species, brackish water species and sea water species, which reflects the characteristics of estuarine ecological environmental transition zone. The number of macrofaunal species increase with the rise of salinity along estuarine environmental gradient of the Changjiang estuary. Along elevational gradient of the tidal flat wetland, species richness and diversity index of macrofauna increased with the rise of individual density and biomass of Scirpus mariqueter. Because there were differences in water dynamics and characteristics of sediment, zonation of macrofaunal community exists in creek sections in the Changjiang estuary. From the bottom of creek, and the bank of creek to grass tidal flat, variations in the composition of species reflects ecological series of macrofaunal community in creek system of estuarine tidal flat wetland. It is emphasized that different spatial scales in heterogeneity determined by estuarine salinity gradient, elevational gradient, salt marsh vegetation and creek system influenced the community structure of macrofauna in the tidal flat wetlands of the Changjiang estuary. Salt marsh vegetation, tidal creek and micro-topographical elements are representative characteristics of natural tidal flat wetland ecosystem in the estuary. When we consider from different spatial scale, estuarine gradients, elevational gradients, tidal creek system, it is evident that they are related to habitats heterogeneity. It is the different scale heterogeneity that contributes to the zoobenthic diversity and community structure in the tidal flat wetland of the estuary. When drawing the program of the wetland restoration we should pay close attention to salt marsh vegetation, elevation and topography (especially tidal creek system) in determining macrofaunal community.

Yuan Xingzhong; Lu Jianjian

2002-01-01

289

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

Scientific Electronic Library Online (English)

Full Text Available Abstract in english 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, water 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, Febru (more) ary, 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.

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

2012-01-01

290

Suspended particulate matter affects the nutrient budget of turbid estuaries: Modification of the LOICZ model and application to the Yangtze Estuary  

Science.gov (United States)

This study estimates the importance of the estuarine suspended particulate matter (SPM) on the nutrient budget of the Yangtze Estuary by using extensive field data and a modified version of the LOICZ biogeochemical model that incorporates the partitioning of the nutrients between dissolved and particulate phases. The value of the nutrient partition coefficient in the Yangtze Estuary shows a similar dependence to that in European estuaries. High values of the Net Ecosystem Metabolism are found, with p-r values equal to ?10.9 mmol C m-2 day?1 for the non-flood season. If nutrient partitioning was neglected this value would be ?2.7 mmol C m-2 day?1, which would have been wrongly interpreted as biological decay and primary production in the turbidity maximum zone and in coastal waters, respectively. The rate of heterotrophy is thus three times higher than when the interaction of SPM with the nutrients is neglected. These results suggest that the estimates of nutrient budgets in turbid estuaries worldwide that ignore the role of SPM in sequestering nutrients, as with most estuarine biogeochemical models, may be incorrect and need to be re-calculated.

Xu, Hao; Wolanski, Eric; Chen, Zhongyuan

2013-07-01

291

Concerns in assessing radiological releases to a major estuary  

International Nuclear Information System (INIS)

Full text: In the State of Virginia, the James River flows into the Chesapeake Bay and from the mouth of the James River to the fall line the river is under the influence of tidal forces. There are several centers of commerce along the river including an international port of call at the mouth of the James. Associated with the centers of commerce are potential sources of radioactive materials for being released to the river. Two hundred miles inland, the Babcock and Wilcox nuclear fuels processing plants are situated along-side the James River, which has been known to flood its banks quickly in the mountainous regions of Virginia. Storage tanks have been swept downstream from this facility in a previous flood. Fortunately, the tanks were not destroyed. Another source of a possible release is the Suny Nuclear Power Station located on the James River about fifty miles from the Chesapeake Bay. In the cities of Norfolk and Newport News, shipyards are fueling and defueling the Navy's nuclear powered fleet. In addition, many of the Navy's ships are carrying nuclear weapons. These activities may also result in an inadvertent release. In assessing the radiological release from any one of the previously mentioned activities, it is obvious that dilution of the material released into the river is a major factor in dose assessment, as well as the fact that the water is brackish and not suitable as a source of potable water. However, dilution in this case may not be the simple solution. We also have to remember that this estuary is under tidal effects, which means that the materials may not be going out to sea to be further diluted as quickly as we would like to think. It may be possible that the material will be carried up river as far as the fall line and deposited, or deposited along the river's banks. From Virginia's experience with the pesticide, Kepone, materials may be deposited along the estuary and enter the food chain thereby necessitating the limitation of taking shellfish and commercial, recreational fishing. A major problem in assessing the environmental impact is determining what isotopes and in what forms will be taken up in species of commercial interest or those species that would otherwise contribute to man's exposure. Even though water to the lower James River is brackish, there may be uses for the water that have not been considered before, such as use by desalinization plants. Currently, the City of Virginia Beach has difficulty maintaining an adequate supply of water and there has been some discussion of building desalinization plants. If such a plant were in operation, the health physicist would have to consider the consequences of the material being concentrated and the problems associated with disposal of resins or contamination of the equipment. Most ships distill water while at sea and probably the still would not be operating while in port; however, the brackish water is used for fire fighting and many prove to be a source of contamination on the piers, unless an advisory was issued. At the mouth of the James River is located a major beach resort and in the event of a major release its business would suffer if the radiological conditions were not assessed and communicated effectively to the public promptly. I would like to conclude this discussion by stating that citizens in states surrounding the Chesapeake Bay have become very sensitive to the environment of the Bay and that they no longer tolerate rivers being used as sewers. As health physicists we also need to be sensitive to these issues and be mindful that estuaries are more complicated than a direct sewer drain to the ocean for wastes even though the discharges may be accidental. (author)

1989-01-01

292

Distribution of Epiphytic Diatoms in a Sub-Tropical Estuary  

Science.gov (United States)

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.

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

2005-05-01

293

Sticky stuff! Seasonal flocculation in a hypertidal estuary  

Science.gov (United States)

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.

Todd, David; Souza, Alejandro; Jago, Colin

2013-04-01

294

Bacterial Communities in Kuantan Estuary of Pahang Malaysia  

Directory of Open Access Journals (Sweden)

Full Text Available Physicochemical parameters influence the vertical spatial distribution of microbial communities in any water bodies. Based on this perspective, a study on physicochemical parameters and bacterial community was carried out from five stations on January-June 2009 at the Kuantan estuary of Pahang, Malaysia. The temperature was ranged from 25.01-27.48°C, salinity fluctuation observed 0.03-25.84 ppt, Dissolved Oxygen (DO) 6.10 to 10.73 mg L-1, specific conductivity ranged from 0.10 to 42.43 mS cm-1, Total Dissolved Solids (TDS) ranged from 0.05 to 26.36 g L-1) and pH varied from 5.69 to 8.11 and chlorophyll a ranged 0.01 to 1.14 ?g L-1. The nitrite concentration was higher at St. 5 (0.19 mg L-1) followed by St. 4 (0.16 mg L-1) and it was lowest at St. 1 (0.13 mg L-1). Similarly, high phosphorus content (0.17 mg L-1) was found at St. 4 followed by St. 5 (0.16 mg L-1) while, it was lowest at St. 1 (0.08 mg L-1). Out of 19 isolated bacteria most dominant bacteria were Citrobacter freundii followed by Leuconostoc sp. and Staphylococcus xylosus. High bacterial colony (cfu mL-1) was observed at St. 4 (570 cfu mL-1) in water column followed by St. 5 (490 cfu mL-1). In contrary, it was lowest at St. 2 (213 cfu mL-1). Meanwhile, the highest bacterial colony in sediment was observed at St. 4 (390 cfu mL-1) followed by St. 5 (333 cfu mL-1). It was lowest observed at St. 2 (167 cfu mL-1). Nevertheless, a continuous monitoring of water quality is needed in this estuary especially at St. 4 and 5 which could be alarming in the long run due to deposition of nutrients from the outlets of fishing villages and industry sources.

K.C.A. Jalal; Y. Kamaruzzaman; A. Fairuz; B. Akbar; S. Shahbudin; Y. Faridah

2010-01-01

295

Resource Assessment for Microalgal/Emergent Aquatic Biomass Systems in the Arid Southwest: Final Report  

Energy Technology Data Exchange (ETDEWEB)

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.

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

296

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

Directory of Open Access Journals (Sweden)

Full Text Available This paper reviews the current state of knowledge of the open waters of the San Francisco Estuary. This estuary is well known for the extent to which it has been altered through loss of wetlands, changes in hydrography, and the introduction of chemical and biological contaminants. It is also one of the most studied estuaries in the world, with much of the recent research effort aimed at supporting restoration efforts. In this review I emphasize the conceptual foundations for our current understanding of estuarine dynamics, particularly those aspects relevant to restoration. Several themes run throughout this paper. First is the critical role physical dynamics play in setting the stage for chemical and biological responses. Physical forcing by the tides and by variation in freshwater input combine to control the movement of the salinity field, and to establish stratification, mixing, and dilution patterns throughout the estuary. Many aspects of estuarine dynamics respond to interannual variation in freshwater flow; in particular, abundance of several estuarine-dependent species of fish and shrimp varies positively with flow, although the mechanisms behind these relationships are largely unknown. The second theme is the importance of time scales in determining the degree of interaction between dynamic processes. Physical effects tend to dominate when they operate at shorter time scales than biological processes; when the two time scales are similar, important interactions can arise between physical and biological variability. These interactions can be seen, for example, in the response of phytoplankton blooms, with characteristic time scales of days, to stratification events occurring during neap tides. The third theme is the key role of introduced species in all estuarine habitats; particularly noteworthy are introduced waterweeds and fishes in the tidal freshwater reaches of the estuary, and introduced clams there and in brackish water. The final theme is the rather heterogeneous set of results from monitoring and research in the estuary. For example, some topics have been subjects of intense activity both in research and monitoring (e.g., physical dynamics of the upper estuary, phytoplankton blooms), while others have received little attention (e.g., microzooplankton). In addition, both research and monitoring have emphasized some regions of the estuary (e.g., the Sacramento-San Joaquin Delta) over others (e.g., San Pablo Bay). In addition, ecological modeling and synthesis has emphasized lower trophic levels over higher. Opportunities for restoration in the open waters of the estuary are somewhat limited by the lack of scientific basis for restoration, and the difficulty in detecting ecosystem responses in the context of high natural variability.

Wim Kimmerer

2004-01-01

297

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

Energy Technology Data Exchange (ETDEWEB)

To determine the origin of sediments in the Savannah River estuary, we have measured {sup 137}Cs and stable isotope ratios of C, N and S in suspended particles and bottom sediments at several sites in the Savannah River and estuary and offshore on the continental shelf. The {sup 137}Cs and stable isotope data were used with a two-endmember mixing model to partition the suspended and bottom sediments at sites along a salinity gradient into riverine and marine fractions. Results from the {sup 137}Cs measurements indicated that {>=} 65% of inorganic sediments in suspension or in the top 5 cm of bottom deposits in the estuary were of marine origin. Stable carbon isotope ratios indicated that {>=}74% of the organic sediments in suspension or on the bottom of the estuary were of marine origin, except for sediments at the lowest salinity estuarine site (< 5ppt) were {<=} 22% of the sediments were marine-derived. Stable N and S isotope ratios were inconclusive, perhaps reflecting isotopic fractionation during sediments diagenesis at some of the sites. Our results suggest that estuaries, particularly those along submergent coastlines such as the eastern United States, are important sinks for inorganic and organic particles and particle-associated materials from the coastal ocean. (author).

Mulholland, P.J.; Olsen, C.R. (Oak Ridge National Lab., TN (United States))

1992-01-01

298

The behaviour of uranium isotopes with salinity change in three U.K. estuaries  

International Nuclear Information System (INIS)

The behaviour of natural uranium isotopes during estuarine mixing has been studied in three British estuaries. Uranium exhibits conservative behaviour in the Clyde and Tamar estuaries but there is evidence of removal in the Forth estuary at salinities -1 occur. Phosphate removal is also observed in the Forth in this salinity range. The uranium removal rate in the upper part of this estuary is estimated at 44 kg y-1. The uranium concentrations and corresponding 234U/238U activity ratios measured for the freshwater end-members of the three rivers are: 0.15 ?g1-1 and 1.65 for the Clyde 0.04 g-1 and 1.44 for the Tamar and 0.09 ?g1-1 and 1.50 for the Forth. Regression analysis gives an overall U/S per mille ratio of (9.53 + -0.84) x 10-8g g-1 over the salinity range 5.0 - 33.2 per mille for all three estuaries, which is in excellent agreement with values obtained by other workers. (author).

1987-01-01

299

Biodiversity of brackish water amphipods (crustacean) in two estuaries, southeast coast of India.  

UK PubMed Central (United Kingdom)

The present study about the gammarid amphipods of Vellar and Uppanar estuaries was performed during two seasons (pre-monsoon and post-monsoon, 2005-2006), respectively, in nine habitats: five in the Vellar estuary and four in the Uppanar estuary. Amphipod samples were collected from sediments, oyster beds, seaweeds, sea grass, and mangroves. A total of 29 species of gammarid amphipods were collected in each area. The surface water temperature ranged from 16°C to 26°C, the salinity from 20 to 32 psu, and the pH between 7.5 and 8.3. Dissolved oxygen ranged from 5.3 to 7.8 ml/l. The maximum abundance of amphipods was observed during the pre-monsoon (July to September) in Vellar mangrove, and it was minimum during the pre-monsoon in Uppanar sea grass. It was found that several physicochemical factors, such as salinity, temperature, dissolved oxygen, pH, and the substrate have a marked effect on the distribution and the relative abundance of amphipods. The ranges of species diversity, richness, dominance, and evenness in the Vellar and Uppanar estuaries were 1.58-4.15, 1.82-5.29, 0-0.11, and 0.96-1, respectively. Using multivariate analyses, in each estuary, it was possible to identify different communities of amphipod species according to their habitats.

Mondal N; Rajkumar M; Sun J; Kundu S; Lyla PS; Khan SA; Trilles JP

2010-12-01

300

Biodiversity of brackish water amphipods (crustacean) in two estuaries, southeast coast of India.  

Science.gov (United States)

The present study about the gammarid amphipods of Vellar and Uppanar estuaries was performed during two seasons (pre-monsoon and post-monsoon, 2005-2006), respectively, in nine habitats: five in the Vellar estuary and four in the Uppanar estuary. Amphipod samples were collected from sediments, oyster beds, seaweeds, sea grass, and mangroves. A total of 29 species of gammarid amphipods were collected in each area. The surface water temperature ranged from 16°C to 26°C, the salinity from 20 to 32 psu, and the pH between 7.5 and 8.3. Dissolved oxygen ranged from 5.3 to 7.8 ml/l. The maximum abundance of amphipods was observed during the pre-monsoon (July to September) in Vellar mangrove, and it was minimum during the pre-monsoon in Uppanar sea grass. It was found that several physicochemical factors, such as salinity, temperature, dissolved oxygen, pH, and the substrate have a marked effect on the distribution and the relative abundance of amphipods. The ranges of species diversity, richness, dominance, and evenness in the Vellar and Uppanar estuaries were 1.58-4.15, 1.82-5.29, 0-0.11, and 0.96-1, respectively. Using multivariate analyses, in each estuary, it was possible to identify different communities of amphipod species according to their habitats. PMID:20082137

Mondal, Nityananda; Rajkumar, Mayalagu; Sun, Jun; Kundu, Sourav; Lyla, P S; Khan, Seyed Ajmal; Trilles, Jean Paul

2010-01-16

 
 
 
 
301

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)

2002-01-01

302

Patterns and trends in sediment toxicity in the San Francisco Estuary.  

UK PubMed Central (United Kingdom)

Widespread sediment toxicity has been documented throughout the San Francisco Estuary since the mid-1980s. Studies conducted in the early 1990s as part of the Bay Protection and Toxic Cleanup Program (BPTCP), and more recently as part of the Regional Monitoring Program (RMP) have continued to find sediment toxicity in the Estuary. Results of these studies have shown a number of sediment toxic hotspots located at selected sites in the margins of the Estuary. Recent RMP monitoring has indicated that the magnitude and frequency of sediment toxicity is greater in the winter wet season than in the summer dry season, which suggests stormwater inputs are associated with sediment toxicity. Additionally, spatial trends in sediment toxicity data indicate that toxic sediments are associated with inputs from urban creeks surrounding the Estuary, and from Central Valley rivers entering the northern Estuary via the Delta. Sediment toxicity has been correlated with a number of contaminants, including selected metals, PAHs and organochlorine pesticides. While toxicity identification evaluations (TIEs) suggest that metals are the primary cause of sediment toxicity to bivalve embryos; TIEs conducted with amphipods have been inconclusive.

Anderson B; Hunt J; Phillips B; Thompson B; Lowe S; Taberski K; Scott Carr R

2007-09-01

303

Simulation of radionuclide fluxes from the Dnieper-Bug Estuary into the Black Sea  

Energy Technology Data Exchange (ETDEWEB)

To simulate the radionuclide flux from the Dnieper-Bug Estuary into the Black Sea the three-dimensional time-dependent flow and transport code THREETOX was used. The prognostic variables of the model are the three components of the velocity field, temperature, salinity, surface elevation, suspended sediment concentration and the radionuclide concentrations in the solute, suspended sediments and bottom deposition. The dispersion of {sup 137}Cs and {sup 90}Sr in the estuary and adjacent shelf area of the Black Sea over the first two years following the Chernobyl accident wasreconstructed. The fluxes of radionuclides from the Dnieper-Bug Estuary into the Black Sea were estimated. The results are in reasonable agreement with the available measurements. It is shown that the differences between the {sup 137}Cs and {sup 90}Sr distributions specific to the Dnieper-Bug Estuary were due to the different geochemical behaviours of these radionuclides. The deviation from a linear correlation between salinity and dissolved {sup 137}Cs concentration in the estuary was shown to be due to exchange processes with contaminated bottom sediments. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

Margvelashvily, N.; Maderich, V.; Zheleznyak, M. [Institute of Mathematical Machines and System Problems, National Academy of Sciences of the Ukraine, Prospect Glushkova, 42 Kiev (Ukraine)

1999-04-01

304

Simulation of radionuclide fluxes from the Dnieper-Bug Estuary into the Black Sea  

International Nuclear Information System (INIS)

To simulate the radionuclide flux from the Dnieper-Bug Estuary into the Black Sea the three-dimensional time-dependent flow and transport code THREETOX was used. The prognostic variables of the model are the three components of the velocity field, temperature, salinity, surface elevation, suspended sediment concentration and the radionuclide concentrations in the solute, suspended sediments and bottom deposition. The dispersion of 137Cs and 90Sr in the estuary and adjacent shelf area of the Black Sea over the first two years following the Chernobyl accident was reconstructed. The fluxes of radionuclides from the Dnieper-Bug Estuary into the Black Sea were estimated. The results are in reasonable agreement with the available measurements. It is shown that the differences between the 137Cs and 90Sr distributions specific to the Dnieper-Bug Estuary were due to the different geochemical behaviours of these radionuclides. The deviation from a linear correlation between salinity and dissolved 137Cs concentration in the estuary was shown to be due to exchange processes with contaminated bottom sediments. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

1999-04-01

305

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

Directory of Open Access Journals (Sweden)

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

P. A. Jenkins; R. W. Duck; J. S. Rowan; J. Walden

2002-01-01

306

Weak and habitat-dependent effects of nutrient pollution on macrofaunal communities of southeast Australian estuaries.  

UK PubMed Central (United Kingdom)

Among the impacts of coastal settlements to estuaries, nutrient pollution is often singled out as a leading cause of modification to the ecological communities of soft sediments. Through sampling of 48 sites, distributed among 16 estuaries of New South Wales, Australia, we tested the hypotheses that (1) anthropogenic nutrient loads would be a better predictor of macrofaunal communities than estuarine geomorphology or local sediment characteristics; and (2) local environmental context, as determined largely by sediment characteristics, would modify the relationship between nutrient loading and community composition. Contrary to the hypothesis, multivariate multiple regression analyses revealed that sediment grain size was the best predictor of macrofaunal assemblage composition. When samples were stratified according to median grain size, relationships between faunal communities and nitrogen loading and latitude emerged, but only among estuaries with sandier sediments. In these estuaries, capitellid and nereid polychaetes and chironomid larvae were the taxa that showed the strongest correlations with nutrient loading. Overall, this study failed to provide evidence of a differential relationship between diffuse nutrient enrichment and benthic macrofauna across a gradient of 7° of latitude and 4°C temperature. Nevertheless, as human population growth continues to place increasing pressure on southeast Australian estuaries, manipulative field studies examining when and where nutrient loading will lead to significant changes in estuarine community structure are needed.

Nicastro A; Bishop MJ

2013-01-01

307

Design and fabrication of a prototype system for photovoltaic residences in the Southwest  

Science.gov (United States)

Described are the design of a photovoltaic powered residence for the American Southwest, dubbed Casa fotovoltaica, and the construction of a prototype building at the Southwest Residential Experiment Station for testing the performance of the full size photovoltaic (PV) system. Included are architectural drawings of both the residence and the prototype, analysis of the energy requirements of the residence, prediction of PV system output, description of the electrical system, and history of the construction process of the prototype.

1982-06-01

308

Assessing spatial and seasonal variations of dissolved organic matter by spectroscopic analysis in a stratified estuary: Yura River Estuary, Japan  

Science.gov (United States)

Dissolved organic matter (DOM) discharged from terrestrial areas may play an important role in global carbon dynamics as well as in estuarine and coastal primary and heterotrophic productivity. Dynamics of DOM in estuarine areas may be affected by various biological processes, such as production of autochthonous DOM and degradation of DOM. A spectroscopic method, which is a three-dimensional excitation emission matrix (EEM) fluorescence analysis has been applied to evaluate the qualitative variation of DOM. Parallel factor (PARAFAC) analysis is a newly introduced statistical modeling method to quantitatively decompose EEMs into individual fluorescent component. Combination of EEMs and PARAFAC analysis is a useful tool for assessing the dynamics of DOM. However our knowledge about the dynamics of individual PARAFAC component in esturine environment is still limited. The Yura River estuary is a typical microtidal estuary, which flows into the Sea of Japan. The estuary is characterized by the seasonal salt-wedge intrusion: In summer and autumn, seawater intrudes into the river approximately 20 km upstream from the river mouth due to the generally low water discharge during the season except for storm-induced sudden increase. In contrast, due to the high precipitation and snowmelt, water discharge is higher and the seawater rarely intrudes into the river in winter and early spring. The main objective of this study is to assess the spatial and seasonal variations of individual fluorophore in the stratified estuarine environment by using EEM-PARAFAC method. Six sampling stations were set between the mouth of the Yura River and the location about 16 km upstream. Twenty sampling stations were set at 5, 10, 20 and 30 m depths in the coastal area. Sampling and observations were carried out seasonally from July 2010 to July 2011. Measurement of vertical profiles of salinity, temperature and chlorophyll fluorescence was conducted by a CTD profiler at each station. We collected surface water samples from all 26 stations, and water samples from different depths at 6 stations located in the river and at 4 coastal stations along the extension of the river. Concentrations of DOC were determined with a total organic carbon analyzer. EEM was measured by using a fluorescent spectrometer. After EEM data were standardized by the Raman correction, several peaks are extracted by the PARAFAC analysis. Our study shows a great variability of DOM in terms of quantity and quality. DOC concentration tended to be high when the water discharge was high during the snowmelt season and in the summer when there was a storm-induced increase in water discharge. Two different terrestrial humic-like components (component 1 and 2) were identified by the PARAFAC analysis and the ratio between the fluorescent intensities of two components was greatly varied seasonally. Our study highlights the applicability of EEM-PARAFAC method to investigate DOM dynamics in esturine environments. This study was conducted as a part of the Kibunka Project, FSERC, at Kyoto University.

Fukuzaki, K.; Watanabe, K.; Fukushima, K.; Akiyama, S.; Fuji, T.; Funahashi, T.; Shirasawa, H.; Ueno, M.; Yamashita, Y.; Yoshioka, T.

2011-12-01

309

Spatio-temporal distribution of suspended particulate matter in the Scheldt estuary (Belgium) and interactions with mesozooplankton  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This is a research study on suspended particulate matter (SPM) in estuaries, specifically in the Scheldt estuary in Belgium. The use of image analysis in studying SPM is being explored. The technique as applied by first by Tackx et al.(1995) in quantifying SPM mass and zooplankton body sizes ...

Billiones, R.G.

310

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...

311

Historic and recent patterns in dissolved oxygen within the Yaquina Estuary (Oregon, USA): Importance of anthropogenic activities and oceanic conditions  

Science.gov (United States)

Spatial and temporal patterns of dissolved oxygen (DO) in Yaquina Estuary, Oregon (USA) are examined using historic and recent data. There was a significant increasing trend in DO in the upstream portion of the estuary during the years 1960â??1985. Historically, minimum dry season ...

312

Geochemisch gedrag van zware metalen in het Schelde-estuarium = Geochemistry of trace metals in the Scheldt estuary  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The distribution of trace metals has been studied in abiotic compartments of the Scheldt estuary (water column and sediments). Seasonal surveys, carried out in 1987-1988, indicate that the geochemistry of dissolved trace metals (Cd, Cu, Zn) is determined by the redox status of the upper estuary, and...

Zwolsman, J.J.G.

313

Biogeochemical behaviour of Cd, Cu, Pb and Zn in the Scheldt estuary during the period 1981-1983  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Cu, Zn, Cd and Pb have been analysed in suspended matter and water samples from the Scheldt estuary, collected during five cruises between May 1982 and May 1983. In order to evaluate the overall metal behaviour in the estuary, continuous longitudinal profiles of the total, the particulate and the di...

Baeyens, W.F.J.; Elskens, M.; Gillain, G.; Goeyens, L.

314

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...

315

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...

316

[Simulation of multimedia fate of phenanthrene in the Yangtze estuary].  

UK PubMed Central (United Kingdom)

A Level III fugacity model is used to simulate the concentration distribution of phenanthrene in air, water, sediment and plants in the Yangtze estuary. Based on simulation results, transfer fluxes among-phase are calculated, and also, the key model parameters are determined by means of sensitivity analysis. The results indicated that the advection of air is the main source of phenanthrene in this area, while the main disappeared way from the study region is the advection of air and water. The degradation of phenanthrene in air is the most and the degradation in sediment is the least. The air is the major store of phenanthrene, where phenanthrene was found accounts for 86.36% of the total amount, however, the phenanthrene concentrations is only 0.5 x 10(-7) mol x m(-3). The phenanthrene concentrations are higher in sediment and plants which are 1.5 x 10(-6) mol x m(-3) and 4.4 x 10(-6) mol x m(-3), respectively. The distribute coefficient and the sedimentation rate of the phenanthrene control the distribution of the phenanthrene in each medium.

Wang ZC; Liu M; Yang Y; Wang LL

2011-08-01

317

Measuring hydrodynamics and sediment transport processes in the Dee estuary  

Directory of Open Access Journals (Sweden)

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.

R. Bolaños; A. Souza

2010-01-01

318

Measuring hydrodynamics and sediment transport processes in the Dee Estuary  

Directory of Open Access Journals (Sweden)

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.

R. Bolaños; A. Souza

2010-01-01

319

An overview of tritium behaviour in the Severn Estuary (UK)  

Energy Technology Data Exchange (ETDEWEB)

Measurements of tritium ({sup 3}H) activity in marine species in the Severn Estuary (UK) show concentrations significantly above those predicted by standard models. Concentration factors of 10{sup 4} 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 {approx}36 {mu}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)

Williams, J.L. [Amersham plc, Cardiff Laboratories, Whitchurch, Cardiff (United Kingdom)]. E-mail: julie.williams@uk.amershambiosciences.com; Russ, R.M. [Amersham plc, Cardiff Laboratories, Whitchurch, Cardiff (United Kingdom); McCubbin, D.; Knowles, J.F. [Centre for Environment, Fisheries and Aquaculture Science, CEFAS Lowestoft Laboratory, Pakefield Road, Lowestoft, Suffolk (United Kingdom)

2001-12-01

320

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.)

1985-01-01

 
 
 
 
321

Changes in Epipelic Diatom Diversity from the Savannah River Estuary  

Directory of Open Access Journals (Sweden)

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

Kalina M. Manoylov; Joseph N. Dominy Jr.

2013-01-01

322

Development of indicators of habitat condition for southeastern estuaries  

Energy Technology Data Exchange (ETDEWEB)

EMAP-Estuaries (Environmental Monitoring and Assessment Program) was extended into the southeast during pilot year studies. The efficacy of core indicators as well as some developmental indicators for classification of habitats as degraded or undegraded was evaluated at 24 stations from NC to Indian River Lagoon, FL. Results from continuous DO recordings indicate a pronounced diurnal/tidal component with periods of hypoxia at most sites, but with more extreme values and longer durations at degraded sites. Amphipod toxicity tests showed poor powers of discrimination, but Microtox assays showed some promise. Assays based on the effects of sediments on growth of seed clams (Mercenaria mercenaria) were developed that also yielded encouraging results. The benthic community data was used to develop an index based on community attributes (such as diversity, pollution sensitivity, dominance) that was very effective at discriminating degraded from undegraded sites. Protocols were also developed for in situ deployment of juvenile oysters (Crassostrea virginica) for evaluation of effects on growth, bioaccumulation, and disease. Oysters deployed at degraded sites had significantly lower growth rates, higher concentrations of metals, and higher incidences of disease.

Ringwood, A.H.; Holland, A.F.; Gilbert, G. [Marine Resources Research Inst., Charleston, SC (United States); Hyland, J. [NOAA, Charleston, SC (United States). Carolinian Province Office

1994-12-31

323

Electrochemical determination of dissolved uranium in Krka River estuary.  

Science.gov (United States)

The applicability of the previously developed method for electrochemical determination of dissolved uranium concentration has been tested on natural water samples taken from the Krka river estuary during various seasons and along different depth profiles. The method is based on the following treatment of the sample: destroying the uranyl-carbonato complexes by adjusting the pH to 3, enabling the formation of adsorbable uranyl-hydroxo complexes by adjusting the pH to 6.5-7.0 and measurement by cathodic stripping voltammetry technique. As the signal of the dissolved uranium reduction is sometimes masked by the signal of the matrix of the sample, a resolution enhancement including digestion and/or deconvolution has to be applied. The measured concentration of dissolved uranium varies in the range from 0.4 to 3.3 x 10(-8) mol l-1, corresponding to the data found in the literature. The depth profile of dissolved uranium concentration distributions shows conservative behaviour. The X-ray fluorescence spectroscopy (XRF) confirmed the applicability of the method, yet pointing out to its limitations caused by the matrix of the solution. PMID:11337837

Djogi?, R; Pizeta, I; Branica, M

2001-06-01

324

Electrochemical determination of dissolved uranium in Krka River estuary.  

UK PubMed Central (United Kingdom)

The applicability of the previously developed method for electrochemical determination of dissolved uranium concentration has been tested on natural water samples taken from the Krka river estuary during various seasons and along different depth profiles. The method is based on the following treatment of the sample: destroying the uranyl-carbonato complexes by adjusting the pH to 3, enabling the formation of adsorbable uranyl-hydroxo complexes by adjusting the pH to 6.5-7.0 and measurement by cathodic stripping voltammetry technique. As the signal of the dissolved uranium reduction is sometimes masked by the signal of the matrix of the sample, a resolution enhancement including digestion and/or deconvolution has to be applied. The measured concentration of dissolved uranium varies in the range from 0.4 to 3.3 x 10(-8) mol l-1, corresponding to the data found in the literature. The depth profile of dissolved uranium concentration distributions shows conservative behaviour. The X-ray fluorescence spectroscopy (XRF) confirmed the applicability of the method, yet pointing out to its limitations caused by the matrix of the solution.

Djogi? R; Pizeta I; Branica M

2001-06-01

325

Greenhouse impacts on the south-west of Western Australia  

Energy Technology Data Exchange (ETDEWEB)

The author attempts to publicise the latest climate scenarios issued in November 1992 by CSIRO which indicate that greenhouse effects will not change winter rainfall in the south-west of Western Australia. They suggest uncertainties of plus or minus 10 per cent for the year 2030. Revised estimates suggest a sea level rise of between 5 and 35 cm by 2030 compared to 1988 estimates of 20-40 cm. A warming of the south coast is now predicted to be 0.5 to 2.0[degree]C and between 0.5 and 2.5[degree]C at about 200Km from the coast, again less than in the 1988 scenario. It is suggested that the impacts of maximum greenhouse effects may be overstated also since they ignore possible cooling effects of sulphate aerosols and CO[sub 2] fertilization. The new data suggest to the author that strategic priorities should be redirected away from greenhouse towards E1 Nino-Southern Oscillation (ENSO) events.

O' Brien, B.J.

1993-03-01

326

Sequence variation analysis of HPV-18 isolates in southwest China.  

UK PubMed Central (United Kingdom)

Intratypic variations of HPV-18 are known to differ in the persistence of the infection, frequency of carcinogenesis and the progression of precursor lesions to advanced cervical cancer. This study was designed to analyze sequence variations of HPV-18 isolates in order to discover novel HPV-18 variants and to evaluate the variations among infected women in southwest China. Cervical biopsies from 56 HPV-18-positive women with cervical neoplasia were assayed by PCR amplification and sequencing of all eight genes (E1, E2, E4, E5, E6, E7, L1, L2) of the HPV-18 genome. The most frequently observed variation was a C to G transversion at nucleotide 287 of E6, which was found in 48.2% of samples. Analysis of E7 revealed only one specimen as having sequence variations. In addition, we have identified several novel variations: A551C in E6, G6906A in L1, and C4915T and C5147A in L2. The mutations in E6 and L2 are silent, while the E7 mutation results in a single amino acid change. This study complements and expands on previous descriptions of HPV-18 variants. The sequence variation data presented here provides a foundation for future research on HPV-induced oncogenesis and may prove valuable for developing diagnostic probes and in the design of HPV vaccines for targeted populations.

Shen M; Ding X; Li T; Chen G; Zhou X

2013-01-01

327

NCLB: Local implementation and impact in southwest Washington state.  

Directory of Open Access Journals (Sweden)

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.

Linda Mabry; Linda Mabry and Jason Margolis

2006-01-01

328

Local Impact of State Testing in Southwest Washington  

Directory of Open Access Journals (Sweden)

Full Text Available A decade after implementation of a state testing and accountability mandate, teachers' practices and perspectives regarding their classroom assessments and their state's assessments of student achievement were documented in a study of 31 teachers in southwest Washington state. Against a background of national trends and standards of psychometric quality, the data were analyzed for teachers' beliefs and practices regarding classroom assessment and also regarding state assessment, commonalities and differences among teachers who taught at grade levels tested by the state and those who did not, teachers' views about the impact of state assessment on their students and their classrooms, and their views about whether state testing promoted educational improvement or reform as intended. Data registered (1) teachers' preferences for multiple measures and their objections to single-shot high-stakes testing as insufficiently informative, unlikely to promote valid inferences of student achievement, and often distortive of curriculum and pedagogy; (2) teachers' objections to the state test as inappropriate for nonproficient speakers of English, for students eligible for special services, and for impoverished students; and (3) teachers' preferences for personalized assessments respectful of student circumstances and readiness, rather than standardized assessments. Teachers' practical wisdom thus appeared more congruent than the state testing program with measurement principles regarding (1) multiple methods and (2) validation for specific test usage, including usage with disadvantaged subgroups of test-takers. Findings contrasted a distinction of emphasis: state focus on "testing students" as distinct from teachers' focus on "testing students."

Linda Mabry; Jayne Poole; Linda Redmond; Angelia Schultz

2003-01-01

329

Mapping crustal stress and strain in southwest British Columbia  

Science.gov (United States)

This paper investigates the orientation and sources of stress in the forearc of the Cascadia subduction zone in southwest British Columbia, using Bayesian inversion results from focal mechanism data and comparing results with GPS derived short-term strain rates. The subduction margin in this region includes a change in orientation from N-S in Washington State to NW-SE in British Columbia. Over 1000 focal mechanisms from North American crustal earthquakes have been calculated to identify the dominant style of faulting, and ˜600 were inverted to estimate the principal stress orientations and the stress ratio. Our results indicate the maximum horizontal compressive stress orientation changes with distance to the trench, from approximately margin-normal along the coast to approximately margin-parallel 100-150 km inland from the coast. Comparing stress orientations with GPS data, we relate the margin-normal stress direction to subduction-related strain rates due to the locked interface between the North American and Juan de Fuca plates just west of Vancouver Island. Further from the margin the plates are coupled less strongly, and the margin-parallel maximum horizontal compressive stress in the North American Plate relates to the northward push of the Oregon Block, which is also observed in the horizontal shortening direction of the residual strain rates, after the subduction component is removed.

Balfour, N. J.; Cassidy, J. F.; Dosso, S. E.; Mazzotti, S.

2011-03-01

330

Premarital sexual activities in an urban society of Southwest- Nigeria  

Directory of Open Access Journals (Sweden)

Full Text Available Premarital sex is associated with the phenomenon of teenage and unintended pregnancies, abortion, the spread of STIs and HIV. The major objective of this study was the investigation of premarital sexual activities in an urban society of South-west Nigeria. The aim is to quantify premarital sexual behaviour in the study population. Interview method was used to collect information from a sample of 2,500 women within the age bracket of 15-49 years. Percentage distribution and logistic regression were used in the analysis. The results reveal a very high rate of sexual activities; 14.24% had had sex before age 14, and 84% had sex before their 20th birthday at which age only 1.28% of the sample had married. Premarital sexual activities are highly associated with age, age at marriage and puberty. The study calls for the empowerment of the younger population especially girl child through sexual right education to avoid the negative consequences associated with premarital sex.

Olubunmi Akinsanya Alo; Isreal Sunday Akinde

2010-01-01

331

Turtle riders: remoras on marine turtles in Southwest Atlantic  

Directory of Open Access Journals (Sweden)

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.

Ivan Sazima; Alice Grossman

2006-01-01

332

Shifts in the synoptic systems influencing southwest Western Australia  

Energy Technology Data Exchange (ETDEWEB)

A self-organising map is used to classify the winter circulation affecting southwest Western Australia (SWWA) into 20 different synoptic types. The changes in the frequency of these types and their links to observed rainfall are analysed to further understand the significant, prolonged, rainfall drop observed in this region since 1975. The temporal variability of the different synoptic types link well with the observed rainfall changes. The frequency of the troughs associated with wet conditions across SWWA has declined markedly since 1975 while the frequency of the synoptic types with high pressure over the continent, associated with dry conditions, has increased. Combining the frequency of the synoptic systems with the amount of observed rainfall allows a quantitative analysis of the rainfall decline. The decreased frequency of the troughs associated with very wet conditions accounts for half of the decline. Reductions in the amount of rainfall precipitating from each system also contribute to the decline. Large-scale circulation changes, including increases in the mean sea-level pressure and a decrease in the general baroclinicity of the region have been associated with the rainfall decline. These changes are suggested to be linked to increasing levels of greenhouse gases. Due to the strong link between the number of trough types and the rainfall over SWWA, the shifts in the frequency of these synoptic types could be used as a tool to assess simulated rainfall changes, particularly into the future. (orig.)

Hope, Pandora K.; Drosdowsky, Wasyl; Nicholls, Neville [Bureau of Meteorology Research Centre, GPO Box 1289, Melbourne (Australia)

2006-06-15

333

The epidemiology and management of gynatresia in Lagos, southwest Nigeria.  

UK PubMed Central (United Kingdom)

OBJECTIVE: To document data from patients presenting with gynatresia at 2 tertiary health centers in Lagos, southwest Nigeria. METHODS: In a prospective, descriptive study, clinical history and physical examination data were collected for women who presented with gynatresia between January 2004 and January 2011. Ultrasonography results and abnormality at surgery were also documented. Where possible, the severity of stenosis and surgical outcome were assessed by published scales. RESULTS: Forty-seven patients were included in the study. Eight patients (17.0%) presented with congenital gynatresia, the commonest cause of which was Mayer-Rokitansky-Küster-Hauser syndrome (4 patients, 50%). Thirty-nine patients (83.0%) presented with acquired gynatresia, the main cause of which was herbal pessaries (30 patients, 76.9%). Herbal pessaries were used to treat fibroids (23 patients, 76.7%), uterovaginal prolapse (3, 10.0%), and infertility (2, 6.7%); and to procure abortion (2, 6.7%). The ages of the patients who used herbal pessary ranged from 18 to 50 years (mean 36.10 ± 1.24 years). Other causes of acquired gynatresia were birth injuries (6 patients, 15.4%), and female genital mutilation (2, 5.1%). CONCLUSION: Acquired gynatresia was more common in Lagos than congenital gynatresia. The causes of acquired gynatresia are preventable and could be eliminated by health education.

Ugburo AO; Fadeyibi IO; Oluwole AA; Mofikoya BO; Gbadegesin A; Adegbola O

2012-09-01

334

Magnetotelluric survey across the active spreading zone in southwest Iceland  

Energy Technology Data Exchange (ETDEWEB)

The results of 10 magnetotelluric soundings, performed along a 11-km-long profile crossing the constructive plate boundary in southwest Iceland, are presented. Apparent resistivities are interpreted by a horizontally stratified earth model to yield a pseudo cross-section along the profile. The crust-mantle interface contains a well conductive layer. The depth to the good conductor increases with age of the crust and the distance from the axial zone. This layer is interpreted as partially molten basalt, at a temperature about 1100/sup 0/C and a volume fraction of the melt phase in the range 10-20%. The high-conductivity layer probably disappears west of the Borgarnes anticlinal axis, which separates the older (to the west) and younger (to the east) flood basalts in western Iceland, indicating that the temperature below the oldest part of the profile lies below the solidus curve of basalt. Recent seismic crustal investigations in the same area indicate a state of partial melting or a magma chamber, which agrees with the results of the magnetotelluric soundings.

Hersir, G.P.; Bjoernsson, A.; Pedersen, L.B.

1984-04-01

335

Sequence stratigraphic control on prolific HC reservoir development, Southwest Iran  

Science.gov (United States)

An important carbonate formation in the Persian Gulf and the onshore oil fields of Southwest Iran is the Lowermost Cretaceous Fahliyan formation. The formation in Darkhowain field consists of unconformity-bounded depositional sequences containing prolific hydrocarbon reservoirs of contrasting origin. Located in the high stand systems tract (HST) of the lower sequence encompassing over 200m of oil column are the most prolific reservoir. Another reservoir is over 80m thick consisting of shallowing-upward cycles that are best developed within the transgressive systems tract of the upper sequence. Vertical facies distribution and their paleobathymetry and geophysical log signatures of the Fahliyan formation in the Darkhowain platform reveal the presence of two unconformity-bounded depositional sequences in Vail et al., Van Wagoner et al., and Sarg. The Fahliyan formation mainly consists of platform carbonates composed of restricted bioclastic lime mudstone to packstone of the platform interior, Lithocodium boundstone or ooid-intraclast-bioclast grainstone of the high energy platform margin and the bioclast packstone to lime mudstone related to the off-platform setting.

Lasemi, Y.; Kondroud, K. N.

2008-01-01

336

Combination chemotherapy for mycosis fungoides: a Southwest Oncology Group study.  

Science.gov (United States)

Between 1972 and 1977, the Southwest Oncology Group studied the following three chemotherapy programs for the treatment of patients with advanced forms of mycosis fungoides: (a) cyclophosphamide, adriamycin, vincristine, and prednisone (CHOP) (seven patients); (b) adriamycin, vincristine, and prednisone (HOP) (five patients); and (c) cyclophosphamide, vincristine, prednisone, and bleomycin (COP plus bleomycin) (12 patients). Among the 24 evaluable patients there was an overall objective response rate of 95% with seven (29%) achieving a complete remission. With the adriamycin-containing chemotherapy, five (42%) of 12 patients achieved a complete remission compared to two (17%) of 12 patients treated with COP plus bleomycin. The median duration of remission (partial plus complete) was longer with the COP plus bleomycin combination (median, 47 weeks) than with the adriamycin-containing combinations (median, 22 weeks; P = 0.03). The median survival for all 24 evaluable patients was 95 weeks and was similar regardless of remission-induction therapy. In summary, combination chemotherapy proved to be effective palliative therapy for advanced mycosis fungoides. PMID:87277

Grozea, P N; Jones, S E; McKelvey, E M; Coltman, C A; Fisher, R; Haskins, C L

1979-04-01

337

Extraction of lithium from resources in south-west England  

Energy Technology Data Exchange (ETDEWEB)

The forecasted increase in demand for lithium stimulated this investigation into the production of lithium carbonate from UK indigenous resources. The largest occurrences of lithium were in South-West England, and the Meldon Aplite in Devonshire was estimated to contain 97,000 t Li. The lithium was contained predominantly in lepidolite mica and also in the minerals petalite, spodumene and amblygonite. The fine grain size of the aplite precluded mineral upgrading. Acid leaching of aplite under autoclave conditions was investigated in order to extract lithium with a low-energy input. Solvent extraction of lithium chloride from a leach liquor using n-butanol was unattractive due to the low organic loadings. The extraction of lithium from acidic sulfate solutions using the sodium salts of alkylphosphoric acids succeeded in producing organic loadings of 0.72 M Li/sup +/, though further investigations would be required before such extractants could be used for leach liquors. The calcination of lepidolite at 800/sup 0/C formed ..beta..-spodumene and the resulting enhancement of lithium extraction was insufficient to justify this heat treatment. The extraction of metals from lepidolite was related to their position in the mica lattice and lithium was extracted in preference to other metals except rubidium.

Murphy, D.

1985-01-01

338

Chronic oil pollution harms Magellanic penguins in the Southwest Atlantic  

Energy Technology Data Exchange (ETDEWEB)

Petroleum pollution is a problem for seabirds along the Southwest Atlantic coast. Twenty-five groups from Salvador, Brazil (12{sup o}58'S) to San Antonio Oeste, Argentina (40{sup o}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. (author)

Garcia-Borboroglu, P. [Centro Nacional Patagonico (CONICET), Chubut (Argentina); Wildlife Conservation Society, New York, NY (United States); Boersma, P.D. [Wildlife Conservation Society, New York, NY (United States); University of Washington, Seattle, WA (United States); Ruoppolo, V. [International Fund for Animal Welfare, Emergency Relief Team - Oiled Wildlife Division, Sao Paolo (BR)] (and others)

2006-02-15

339

Epidemiological evaluation of onchocerciasis along Ogun River System, southwest Nigeria  

Directory of Open Access Journals (Sweden)

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.

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

2012-01-01

340

DNA adduct analysis and histopathological biomarkers in European flounder (Platichthys flesus) sampled from UK estuaries  

International Nuclear Information System (INIS)

The presence of genotoxic and potentially carcinogenic chemical contaminants in the estuarine and coastal marine environment is well documented. In this study, European flounder (Platichthys flesus) sampled from eight UK estuaries were analysed for hepatic DNA adducts, using the 32P-postlabelling assay and liver histopathology as part of an on going survey to establish the health status of UK estuaries. Fish were collected from the estuaries Tyne, Mersey, Thames, Alde (reference site), Belfast, Forth, Clyde and Southampton. At the majority of contaminated sites (Southampton, Thames, Clyde, Tyne and Mersey) the predominant DNA adduct profile consisted of diagonal radioactive zones (DRZs). In contrast, flounder collected from the Forth, Alde and Belfast lacked DRZs with only background levels of DNA damage being observed. Statistically significant differences were observed between several of the sites sampled with the hepatic DNA adduct levels detected in flounder from Southampton, Thames and Clyde statistically elevated (P

2004-08-18

 
 
 
 
341

A survey of radioactivity in the Ribble Estuary. I: Activity concentrations and estuarine dynamics  

International Nuclear Information System (INIS)

[en] Activity concentrations of Sellafield-derived (137Cs, 241Am, 238Pu and 238,240Pu) and Springfields-derived (234mPa, 234Th, uranium and thorium) radionuclides in surface sediments were measured at sites throughout the Ribble Estuary between September, 1991 and January, 1993. Measurements were made during periods when BNFL, Springfields were discharging effluent from the processing of uranium ore concentrates (UOC) and during periods following shutdown of the process. The activity concentrations measured agreed well with observations made by other workers. The geology of the Ribble Estuary catchment made only a small contribution to the measured radionuclide activity concentrations. Sellafield-derived radionuclides exhibited a well defined relationship with grain-size (% -1 for 234mPa, were seen in fine-grained sediments deposited near the tidal limit of the Ribble Estuary and Savick Brook. (author)

1994-01-01

342

Report on the usage of computer models of estuaries by eastern coastal states. Special report series  

Energy Technology Data Exchange (ETDEWEB)

The report is the result of an initiative by the State of North Carolina to investigate how estuary models are used by other East Coast states. The NC Division of Environmental Management (NCDEM) has embarked upon a program of Whole Basin Planning. In their evaluation of estuary models for use in this effort, the NCDEM needed more information about the adequacy of their existing modeling tools, as well as potential alternatives. The NCDEM Technical Support Branch staff noted that state agency modelers have a different set of concerns than do federal, private, or academic modelers. The project was also intended to foster a network of state-level estuary modelers to discuss these concerns. The project began in the spring of 1992 with a written survey. Nineteen responses were received, primarily from experienced modelers. The report presents the results of these information gathering activities.

Smith, K.

1992-08-01

343

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

Energy Technology Data Exchange (ETDEWEB)

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).

Clark, N.A.; Kirby, J.S.; Langston, R.H.W.; Donald, P.; Mawdesley, T.; Evans, J.

1990-12-01

344

Variability in waterfowl distribution within hypertidal estuaries in relation to sediments  

International Nuclear Information System (INIS)

[en] 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)

1993-01-01

345

Factors controlling the concentrations of soluble phosphorus in the Mississippi estuary  

Energy Technology Data Exchange (ETDEWEB)

Sediments from the Mississippi River estuary were suspended in solutions with a range of salinities and various initial concentrations of phosphate. After 42 days the suspensions had nearly uniform values for the ion activity product of calcium times biphosphate, (Ca/sup 2 +/)(HPO/sub 4//sup 2 -/) approx. = 10/sup -9/ M/sup 2/. Similar values were observed for this ion product in the Mississippi River and in the upper estuary, suggesting that the concentration of soluble phosphorus may be controlled by an equilibrium with sedimentary material. The data are consistent with a mechanism where soluble phosphorus is controlled by hydrolysis on the surface of hydroxyapatite particles. Phosphorus levels in the lower estuary are controlled primarily by dilution with low-nutrient waters from the Gulf of Mexico.

1985-07-01

346

Baseline metals pollution profile of tropical estuaries and coastal waters of the Straits of Malacca.  

UK PubMed Central (United Kingdom)

The status report on metal pollution in tropical estuaries and coastal waters is important to understand potential environmental health hazards. Detailed baseline measurements were made on physicochemical parameters (pH, temperature, redox potential, electrical conductivity, salinity, dissolved oxygen, total dissolved solid), major ions (Na, Ca, Mg, K, HCO3, Cl, SO4 and NO3) and metals concentrations ((27)Al, (75)As, (138)Ba, (9)Be, (111)Cd, (59)Co, (63)Cu, (52)Cr, (57)Fe, (55)Mn, (60)Ni, (208)Pb, (80)Se, (66)Zn) at estuaries and coastal waters along the Straits of Malacca. Principal component analysis (PCA) was employed to reveal potential pollution sources. Seven principal components were extracted with relation to pollution contribution from minerals-related parameters, natural and anthropogenic sources. The output from this study will generate a profound understanding on the metal pollution status and pollution risk of the estuaries and coastal system.

Looi LJ; Aris AZ; Wan Johari WL; Md Yusoff F; Hashim Z

2013-09-01

347

Distribution, transport and exchanges of fine sediment, with tidal power implications: Severn Estuary, UK.  

UK PubMed Central (United Kingdom)

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.

Kirby R

2010-01-01

348

Distribution, transport and exchanges of fine sediment, with tidal power implications: Severn Estuary, UK.  

Science.gov (United States)

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

Kirby, R

2010-02-12

349

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

Science.gov (United States)

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 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.

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

1993-01-01

350

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

UK PubMed Central (United Kingdom)

Sequential extraction of Hg was performed in a core collected from intertidal area in Ulhas Estuary in order to characterize the downward distribution and diagenetic behavior of Hg in a polluted estuary. Concentration of total Hg ranged between 0.46 and 6.40 microg g(-1) with significant decrease in surficial sediment as a result of closing of two Hg-cell based chlor-alkali plants. Results of sequential extraction showed that>65% Hg was strongly bound to organo-sulphur and inorganic sulphide species that are not bioavailable. Flux of only 18.8% of Hg was found compared to its value deposited on sediment-water interface. Hence, it is concluded that there is no significant diagenetic remobilization of Hg in Ulhas Estuary. This core also has been analyzed for (210)Pb geochronology. The estimated sedimentation rate is 0.31 cm y(-1) in the present sampling region.

Ram A; Borole DV; Rokade MA; Zingde MD

2009-11-01

351

Modeling the transport and distribution of fecal coliform in a tidal estuary.  

UK PubMed Central (United Kingdom)

A laterally averaged two-dimensional fecal coliform transport model incorporated into hydrodynamic and salt modules was developed to simulate the fate and transport of fecal coliform in the tidal Danshui River estuary of northern Taiwan. We validated the developed model with measured data, including longitudinal velocity, salinity, and fecal coliform concentration, collected in 2000. The simulated results of current, salinity, and fecal coliform concentration quantitatively agreed well with the measured data. The model sensitivity analysis indicated that the mortality rate plays an important role in the distribution of fecal coliform concentrations along the tidal Danshui River estuary to Tahan Stream. The validated model was applied to investigate the effects of different freshwater discharges at upstream boundaries on the distributions of fecal coliform. The results revealed that low freshwater discharge resulted in a higher fecal coliform concentration at upstream reaches but had little influence on the downstream of the estuary.

Liu WC; Huang WC

2012-08-01

352

Modeling the transport and distribution of fecal coliform in a tidal estuary.  

Science.gov (United States)

A laterally averaged two-dimensional fecal coliform transport model incorporated into hydrodynamic and salt modules was developed to simulate the fate and transport of fecal coliform in the tidal Danshui River estuary of northern Taiwan. We validated the developed model with measured data, including longitudinal velocity, salinity, and fecal coliform concentration, collected in 2000. The simulated results of current, salinity, and fecal coliform concentration quantitatively agreed well with the measured data. The model sensitivity analysis indicated that the mortality rate plays an important role in the distribution of fecal coliform concentrations along the tidal Danshui River estuary to Tahan Stream. The validated model was applied to investigate the effects of different freshwater discharges at upstream boundaries on the distributions of fecal coliform. The results revealed that low freshwater discharge resulted in a higher fecal coliform concentration at upstream reaches but had little influence on the downstream of the estuary. PMID:22652036

Liu, Wen-Cheng; Huang, Wei-Cher

2012-05-29

353

Spatial variation and subcellular binding of metals in oysters from a large estuary in China.  

UK PubMed Central (United Kingdom)

Pearl River Estuary (PRE) is the largest estuary in Southern China and there has been an increasing concern of metal pollution due to regional industrialization. In this study, we investigated the spatial variation of metal pollution (Ag, As, Cd, Cu, Pb, and Zn) as well as their subcellular handling in the oyster Crassostrea hongkongensis. Hot spots of metal contamination in the oysters were found in different sites, suggesting that there were different sources of metals in the estuary associated with industrial activity. Metals differed in their subcellular bindings in the oysters from different locations. Metal distribution in the biologically detoxified fraction decreased for Cu but increased for Zn with increasing contamination in the oysters. For Zn, there was a significant difference in its two detoxification pools (metal-rich granules and metallothionein-like proteins) in response to Zn contamination. The high Cd concentrations in oysters may carry a high Cd hazard to the consumers.

Yu XJ; Pan K; Liu F; Yan Y; Wang WX

2013-05-01

354

Sessile ciliates on artificial substrata submerged in a polluted estuary (Santos, SP, Brazil)  

Directory of Open Access Journals (Sweden)

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.

Verena Rapp de Eston

1985-01-01

355

Dominance of point source in heavy metal distributions in sediments of a major Sydney estuary (Australia)  

Energy Technology Data Exchange (ETDEWEB)

Size-normalized (<63 {mu}m) distributions of Cu, Zn, and Pb in the surficial sediments of one of Sydneys` four major estuaries - the Georges River/Botany Bay estuary - are not facies or depositionally controlled, but rather their distribution is dominated by source. Point source (waste dumps, sewage overflows, and discharge form a polluted river) are responsible for elevating sediment heavy-metal concentrations up to 50 times above background. Nonpoint sources contribute in raising baseline levels to four times background and comprise mainly stormwater and also marinas, moorings, and wharfs/jetties. Heavy metals disgorged from a point soruce (Cooks River) strongly impact the sediments in the lower estuary, which has implications for the construction of a new runway for Sydney airport. (orig.)

Birch, G. [Environmental Geology Group, Geology and Geophysics Dept., Univ. of Sydney (Australia); Evenden, D. [Environmental Geology Group, Geology and Geophysics Dept., Univ. of Sydney (Australia); Teutsch, M.E. [Environmental Geology Group, Geology and Geophysics Dept., Univ. of Sydney (Australia)

1996-12-01

356

Bioaccumulation of metals by Fucus ceranoides in estuaries of South West England.  

UK PubMed Central (United Kingdom)

Fucus ceranoides tolerates abiotic conditions encountered across the full range of estuarine salinities. We examined the bioaccumulation of metals in individuals and metal concentrations in accompanying sediment samples collected at different locations along estuaries of South West England. Intra- and inter-estuarine variations in metal accumulation by F. ceranoides, after correction for particulate contamination using Fe as a proxy, were attributed to variations in the availabilities and concentrations of aqueous metals. Greatest accumulation was observed in estuaries that remain most heavily impacted by historical mining activities and for metals that were mobilised to the greatest extent during these operations (As, Cu, Sn, Zn). Arsenic concentrations displayed a seaward increase in estuaries in which multiple samples were taken, whereas Cd concentrations were always greatest in samples collected from the most landward locations. Ongoing research aims to better understand the mechanisms and kinetics of metal interactions with F. ceranoides and their dependence on salinity.

Varma R; Turner A; Brown MT

2011-11-01

357

Mercury content in the water and marine organisms in Angke Estuary, Jakarta Bay  

Energy Technology Data Exchange (ETDEWEB)

The methyl-mercury pollution in the marine as well as in estuarine or brackish water environment usually due to industrial waste. In some locations of the Jakarta Bay, the mercury content in sea water was in the range 2.8 to 35.2 ppb and tends to be increase with the rapidly industrial growth in the Jakarta. These values were higher than the normal level of mercury in sea water which usually was not more than 0.15 ppb. The Angke Estuary is one of the fishing area especially for the Jakarta Brackish water culture. This estuary received industrial wastes from the Jakarta city and neighboring areas. In the present paper, the author reports, the result of observation of mercury content in the river water, sea water and marine organisms in Angke Estuary, Jakarta Bay.

Hutagalung, H.P.

1987-09-01

358

Contrasting metal concentrations in selectively extracted suspended versus deposited sediments of the Fraser River Estuary  

Energy Technology Data Exchange (ETDEWEB)

In order to assess the relative importance of Suspended Particulate Material (SPM) and deposited sediment as potential sources of trace metals to estuarine organisms, both SPM and deposited sediment were collected from three sites in the midestuarine region of the Fraser River Estuary over the course of one year. Selective chemical extractions were employed to assess differences in metal geochemical association between SPM and deposited sediment. Results indicate that SPM is an important metal-bearing vector in the estuary. SPM has significantly higher organic content (1--8 times) and metal levels (2--10 times) than deposited sediment and is also made up of smaller material (and therefore has a larger surface area to volume). The geochemical phase with which the metal associates also differs among the two sources and is metal specific. Such differences can have important implications in regards to metal exposure and uptake in suspension and deposit feeding organisms of the estuary.

Stecko, J.R.P.; BendellYoung, L.I. [Simon Fraser Univ., Burnaby, British Columbia (Canada). Dept. of Biological Sciences

1995-12-31

359

Baseline metals pollution profile of tropical estuaries and coastal waters of the Straits of Malacca.  

Science.gov (United States)

The status report on metal pollution in tropical estuaries and coastal waters is important to understand potential environmental health hazards. Detailed baseline measurements were made on physicochemical parameters (pH, temperature, redox potential, electrical conductivity, salinity, dissolved oxygen, total dissolved solid), major ions (Na, Ca, Mg, K, HCO3, Cl, SO4 and NO3) and metals concentrations ((27)Al, (75)As, (138)Ba, (9)Be, (111)Cd, (59)Co, (63)Cu, (52)Cr, (57)Fe, (55)Mn, (60)Ni, (208)Pb, (80)Se, (66)Zn) at estuaries and coastal waters along the Straits of Malacca. Principal component analysis (PCA) was employed to reveal potential pollution sources. Seven principal components were extracted with relation to pollution contribution from minerals-related parameters, natural and anthropogenic sources. The output from this study will generate a profound understanding on the metal pollution status and pollution risk of the estuaries and coastal system. PMID:23809293

Looi, Ley Juen; Aris, Ahmad Zaharin; Wan Johari, Wan Lutfi; Md Yusoff, Fatimah; Hashim, Zailina

2013-06-27

360

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.

1985-01-01

 
 
 
 
361

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

362

Yellow eel (Anguilla anguilla) development in NW Portuguese estuaries with different contamination levels.  

Science.gov (United States)

The aims of the present study were to compare the health status of yellow eels (Anguilla anguilla) developing in three estuaries of the NW Portuguese coast with different levels of pollution and their physiological responses to combined effects of environmental variation and pollution. For this, a field study was performed using a multi-parameter approach, including eels condition indexes and biomarkers, water quality variables and other environmental factors. Sixteen biological parameters were assessed, namely: hepatosomatic index (LSI), Fulton's condition index (K), lipid peroxidation (LPO), total glutathione (TG), reduced glutathione (GSH), oxidised glutathione (GSSG), GSH/GSSG, and the activity of the enzymes acetylcholinesterase (AChE), lactate dehydrogenase (LDH), sodium-potassium ATPase (Na(+)/K(+)-ATPase), ethoxyresorufin O-deethylase (EROD), glutathione S-transferases (GST), catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione reductase (GR). Ten environmental factors were also measured in water: temperature, salinity, pH, phosphates, nitrates, nitrites, ammonium, silica, phenol and hardness. Globally, the biomarkers indicate exposure and toxic effects of pollutants on eels living in contaminated estuaries. The relationships between biological and environmental variables were assessed through redundancy analysis. K and LSI indexes, AChE and Na(+)/K(+)-ATPase, total glutathione levels and the antioxidant enzymes CAT, GR, and SOD where the factors most discriminating reference (Minho River estuary) from contaminated estuaries (Lima and Douro Rivers estuaries). Moreover, the most striking outcomes of pollutants exposure on biological responses were observed during winter, probably due to a joint effect of cold weather and pollution stress. Altogether, the results indicate that the development of eels in the polluted estuaries of Lima and Douro rivers is interfering with physiological functions determinant for their survival and performance. This may increase the mortality rates during the continental life-phase of the species and decrease the percentage of animals able to successfully complete their oceanic migration and, thus, reduce the contribution of each generation to the next one. PMID:19123036

Guimarães, Laura; Gravato, Carlos; Santos, Joana; Monteiro, Luís S; Guilhermino, Lúcia

2009-01-03

363

Seasonal movements of American horseshoe crabs Limulus polyphemus in the Great Bay Estuary, New Hampshire (USA)  

Directory of Open Access Journals (Sweden)

Full Text Available The goal of this study was to determine the year round movement patterns of American horseshoe crabs, Limulus polyphemus, in the Great Bay Estuary, New Hampshire (USA) by using acoustic telemetry to track the movements of 37 adult Limulus, for periods ranging from 2 to 31 months. During the winter (December-March) horseshoe crabs moved very little. In the spring, when water temperatures exceeded 11oC, horseshoe crabs moved at least 1 km further up into the estuary to shallower subtidal areas about a month prior to spawning. The mean distance traveled during spring migrations was 2.6 ± 0.5 (n=20) km up the estuary. Mating occurred in May and June and during these months animals spent most of their time in shallow subtidal areas adjacent to mating beaches. In the summer (July-August), animals moved 1.5 ± 0.5 (n=26) km down the estuary, towards the ocean, and ranged widely, using extensive portions of the estuary. In the fall (September-November) movement was more limited (0.5 ± 0.5 km; n = 24) while animals settled into wintering locations, where they remained until spring. The mean annual linear range for all animals was 4.5 ± 0.3 km (n =35) and the maximum distance traveled by an individual horseshoe crab within one year was 9.2 km. There was no evidence that any of the horseshoe crabs tracked during this study left the estuary [Current Zoology 56 (5): 587–598, 2010].

Susanne Y. SCHALLER, Christopher C. CHABOT, Winsor H. WATSON III

2010-01-01

364

Yellow eel (Anguilla anguilla) development in NW Portuguese estuaries with different contamination levels.  

UK PubMed Central (United Kingdom)

The aims of the present study were to compare the health status of yellow eels (Anguilla anguilla) developing in three estuaries of the NW Portuguese coast with different levels of pollution and their physiological responses to combined effects of environmental variation and pollution. For this, a field study was performed using a multi-parameter approach, including eels condition indexes and biomarkers, water quality variables and other environmental factors. Sixteen biological parameters were assessed, namely: hepatosomatic index (LSI), Fulton's condition index (K), lipid peroxidation (LPO), total glutathione (TG), reduced glutathione (GSH), oxidised glutathione (GSSG), GSH/GSSG, and the activity of the enzymes acetylcholinesterase (AChE), lactate dehydrogenase (LDH), sodium-potassium ATPase (Na(+)/K(+)-ATPase), ethoxyresorufin O-deethylase (EROD), glutathione S-transferases (GST), catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione reductase (GR). Ten environmental factors were also measured in water: temperature, salinity, pH, phosphates, nitrates, nitrites, ammonium, silica, phenol and hardness. Globally, the biomarkers indicate exposure and toxic effects of pollutants on eels living in contaminated estuaries. The relationships between biological and environmental variables were assessed through redundancy analysis. K and LSI indexes, AChE and Na(+)/K(+)-ATPase, total glutathione levels and the antioxidant enzymes CAT, GR, and SOD where the factors most discriminating reference (Minho River estuary) from contaminated estuaries (Lima and Douro Rivers estuaries). Moreover, the most striking outcomes of pollutants exposure on biological responses were observed during winter, probably due to a joint effect of cold weather and pollution stress. Altogether, the results indicate that the development of eels in the polluted estuaries of Lima and Douro rivers is interfering with physiological functions determinant for their survival and performance. This may increase the mortality rates during the continental life-phase of the species and decrease the percentage of animals able to successfully complete their oceanic migration and, thus, reduce the contribution of each generation to the next one.

Guimarães L; Gravato C; Santos J; Monteiro LS; Guilhermino L

2009-05-01

365

The effects of organic inputs to estuaries on overwintering bird populations and communities  

Energy Technology Data Exchange (ETDEWEB)

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).

Green, P.T.; Hill, D.A.; Clark, N.A.

1992-06-01

366

The effects of organic inputs to estuaries on overwintering bird populations and communities  

International Nuclear Information System (INIS)

[en] 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)

1992-01-01

367

Biomarkers in mangrove root crab Goniopsis cruentata for evaluating quality of tropical estuaries.  

UK PubMed Central (United Kingdom)

The present study reports the use of biomarkers analyzes in mangrove root crab Goniopsis cruentata tissues to assess the environmental quality of two tropical estuarine areas. Animals from Ceará River estuary presented inhibition of ChE and GST enzymatic activities and higher rates of DNA damage with respect to those sampled in a pristine environment. G. cruentata appears to represent a proper species to monitor the quality of tropical estuaries. Since Ceará River is a legally protected area, this survey highlight the needs to implement actions to control pollution loads and improve the protection of natural ecosystems and resources.

Davanso MB; Moreira LB; Pimentel MF; Costa-Lotufo LV; Abessa DM

2013-03-01

368

Heavy metals in bivalves collected from river estuaries of Thailand. [Perna viridis  

Energy Technology Data Exchange (ETDEWEB)

This investigation was undertaken to determine the levels of lead, zinc, copper, cadmium, and mercury in five species of bivalves collected from six river estuaries of Thailand during July 1978 to January 1979. The in situ bioassay for studying heavy metals uptake by green mussels (Perna viridis) was also conducted at the Chao Phraya river estuary during February 1980 to March 1981. The results revealed high contamination of lead in mussels during the period of river run-off. The factors that might contribute to this incidence were discussed. Contaminations of the other four metals in bivalves did not show great variation and they were still within the acceptable limits.

Menasveta, P.; Cheevapora, V.; Wongwit, C.

1984-01-01

369

Heavy metal and organic hydrocarbons in sediments from the Waikareao Estuary, Tauranga Harbour, New Zealand  

Energy Technology Data Exchange (ETDEWEB)

We have Previously reported the levels of some organochlorine compounds (PCBs, DDT, DDE, chlordanes and dieldrin) in sediments and three species of shellfish from the Waikareao Estuary, a small inlet of Tauranga Harbour, New Zealand. The detection of elevated levels of organochlorine compounds in some sediments and shellfish species prompted us to also determine the levels of some environmentally significant heavy metals (Cu, Pb, Zn and Cd) and three groups of organic hydrocarbons (PAHs, n-alkanes and hopane triterpenes) in sediments from eleven sites in the Waikareao Estuary. 16 refs., 2 figs., 5 tabs.

Burggraaf, S.; Wilkins, A.L.; Langdon, A.G.; Kim, N.D. [Univ. of Waikato, Hamilton (New Zealand)

1997-06-01

370

Oceanography and Quaternary geology of the St. Lawrence Estuary and the Saguenay Fjord  

International Nuclear Information System (INIS)

The St. Lawrence Estuary is an environment marked by important freshwater discharge and well stratified water masses, recording large seasonal contrast in surface waters from freezing conditions in winter to temperate conditions in summer due to a very strong seasonal cycle in overlying air temperature. High productivity takes place in the pelagic and benthic environments, where a recent trend toward bottom water hypoxia is observed. The area was profoundly marked by the Quaternary glaciations. Thick glaciomarine sequences dating from the last deglaciation are observed in the Estuary and along the shores, whereas a relatively thin layer (a few meters at most) of hemipelagic mud was deposited during the Holocene.

2010-07-12

371

New quantitative approaches for classifying and predicting local-scale habitats in estuaries  

Science.gov (United States)

This study has developed quantitative approaches for firstly classifying local-scale nearshore habitats in an estuary and then predicting the habitat of any nearshore site in that system. Both approaches employ measurements for a suite of enduring environmental criteria that are biologically relevant and can be easily derived from readily available maps. While the approaches were developed for south-western Australian estuaries, with a focus here on the Swan and Peel-Harvey, they can easily be tailored to any system. Classification of the habitats in each of the above estuaries was achieved by subjecting to hierarchical agglomerative clustering (CLUSTER) and a Similarity Profiles test (SIMPROF), a Manhattan distance matrix constructed from measurements of a suite of enduring criteria recorded at numerous environmentally diverse sites. Groups of sites within the resultant dendogram that were shown by SIMPROF to not contain any significant internal differences, but differ significantly from all other groups in their enduring characteristics, were considered to represent habitat types. The enduring features of the 18 and 17 habitats identified among the 101 and 102 sites in the Swan and Peel-Harvey estuaries, respectively, are presented. The average measurements of the enduring characteristics at each habitat were then used in a novel application of the Linkage Tree (LINKTREE) and SIMPROF routines to produce a "decision tree" for predicting, on the basis of measurements for particular enduring variables, the habitat to which any further site in an estuary is best assigned. In both estuaries, the pattern of relative differences among habitats, as defined by their enduring characteristics, was significantly correlated with that defined by their non-enduring water physico-chemical characteristics recorded seasonally in the field. However, those correlations were substantially higher for the Swan, particularly when salinity was the only water physico-chemical variable employed. The lower correlations obtained for the Peel-Harvey were due either to little or erratic variability in particular water physico-chemical variables and/or to the spatial differences in those variables not being well captured by those in the enduring data. Preliminary studies in each estuary indicate that the pattern of relative differences among habitats in the compositions of their fish and benthic invertebrate assemblages are closely correlated with those in their enduring characteristics. Such complementation would allow reliable prediction of the species likely to occupy any nearshore site in an estuary, simply by using the current predictive approach to assign that site to its most appropriate habitat.

Valesini, Fiona J.; Hourston, Mathew; Wildsmith, Michelle D.; Coen, Natasha J.; Potter, Ian C.

2010-03-01

372

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)

2009-01-01

373

Filtration activity of mollusks Mya arenaria L. (Bivalvia) in estuaries of the southern Baltic Sea  

Directory of Open Access Journals (Sweden)

Full Text Available This article argues that, in the estuaries the South Baltic, the bivalve molluscs Mya arenaria are capable of consuming an average of 6.5 % of the water body primary production. A numerical assessment of the filtration rate of these molluscs shows that they can filter daily an average of 2.41 ± 1.01 m3 of water per a square meter of the river bed. During the vegetation season, molluscs can clear approximately 380 m3 of water in estuaries removing up to 558.9 ± 65.7 g of suspended organic matters.

Filippenko D.

2013-01-01

374

COMPLEX ESTIMATION OF BIODIVERSITY OF BREEDING WATERFOWL COMMUNITIES OF MOLOCHNY ESTUARY: MODERN STATE AND PROGNOSIS  

Directory of Open Access Journals (Sweden)

Full Text Available On results the long-term researches conducted in 1988-2008 the estimation of dynamics of biodiversity the nestingbirds’ community of Molochny estuary was performed. The breeding birds’ community of reeds, saline lands, sandyislands and spits, arboreal-shrub jungles were estimated. Is is proved that the gulls, terns, cormorants and passerineswere the dominant species during the period of high water. Maximum specific variety was also proved for this timeperiod. In drought seasons of 2001-2010 the water level in estuary went down sharply that had resulted in the decline ofbiodiversity and amount of breeding birds. Negative trend of biodiversity level was discussed.

Koshelev V.?.; Dubynyna-Pakhushchaya Y.Y.

2011-01-01

375

Some factors regulating the striped bass population in the Sacramento--San Joaquin Estuary, California  

International Nuclear Information System (INIS)

[en] The abundance of young and adult striped bass (Morone saxatilis) in the Sacramento--San Joaquin Estuary is related to the magnitudes of water diversions and of water flows in the estuary. Principal variations in survival occur during the first two months of life. Density-independent mortality caused by the loss of young bass in water diversions is a major factor regulating population size. Population size also is directly related to flow rates, which serve to control the transport of young bass to suitable nursery areas, which in turn influence survival through factors such as food availability

1977-05-02

376

Design of a basinwide monitoring program for the Tampa Bay estuary. Final technical pub  

Energy Technology Data Exchange (ETDEWEB)

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.

Hochberg, R.J.; Weisberg, S.B.; Frithsen, J.B.

1992-10-30

377

STUDY ON THE EFFECTS OF TIDE ON SEDIMENTATION IN ESTUARIES OF THE NIGER DELTA, NIGERIA  

Directory of Open Access Journals (Sweden)

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.

Charles Chizom Dike; Jonah Chukwuma Agunwamba

2012-01-01

378

Sequential data assimilation in an upwelling influenced estuary  

Science.gov (United States)

We have evaluated the impact of assimilating chlorophyll, nitrate, phosphate, silicate and ammonium into a coupled 1D hydrodynamic ecosystem model (GOTM-ERSEM) in an upwelling influenced estuary. The assimilation method chosen is the Ensemble Kalman Filter (EnKF), which has been demonstrated to improve field estimates of key variables (chlorophyll, nutrients) for bulk algal bloom prediction. The 1D model has been set up for a central station inside the Ría de Vigo (Spain). Data from bi-weekly surveys are used to constrain the model. Temperature and salinity profiles are used to ensure the correct representation of the water structure through a relaxation scheme. Chlorophyll extracts and nutrients at three depths are assimilated sequentially during 1 year simulation (1991). The assimilation period includes episodes of active upwelling and downwelling. All five assimilated variables are successfully constrained and represent a large improvement on the reference simulation (without assimilation). Small divergences can be related to poorly resolved physical processes in the model. The assimilation was further evaluated by comparing observed biomass partitioning with model results. Diatoms accounted for the largest biomass update and the largest improvement in terms of percentage of variance explained (R2). This is particularly significant as they represent the 46% of the yearly integrated observed biomass of the planktonic autotrophs. Nonetheless the R2 value was low for all phytoplankton groups. Bacteria and nanoflagellates showed an improvement with respect to their yearly Root Mean Square (RMS), while the other functional groups worsen or remained unaffected. Chlorophyll assimilation was responsible for most of the impact on the phytoplankton biomass with small contributions from the silicate. It had minor impact on the updates of nutrients which in turn corrected the state variables related to the detrital pool. In this current setting, combined assimilation of chlorophyll and nutrients is not sufficient to produce a skillful simulation of the phytoplankton succession.

Torres, R.; Allen, J. I.; Figueiras, F. G.

2006-05-01

379

PREDICTION OF TSUNAMI PROPAGATION IN THE PEARL RIVER ESTUARY  

Directory of Open Access Journals (Sweden)

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

Sun J. S.; Wai, O.W.H.; Chau, K.T.; Wong, R.H.C

2009-01-01

380

Potential for increased mercury accumulation in the estuary food web  

Directory of Open Access Journals (Sweden)

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.

Jay A. Davis; Donald Yee; Joshua N. Collins; Steven E. Schwarzbach; Samuel N. Luoma

2003-01-01

 
 
 
 
381

Debated opinion of the Environmental Authority on the demand of modification of the decree authorizing the creation of the Blayais (units 3 and 4) base nuclear installation (INB), in the district of Gironde, with a view of introduction of MOX fuel  

International Nuclear Information System (INIS)

[en] In this opinion, the Environmental Authority (Ae) first outlines three major stakes which are respectively dealing with health, environment (estuary ecological equilibrium), and accidental risk. After having recalled and commented the backgrounds and objectives of this project, this report recalls the background of the associated procedure. It proposes an analysis of the impact study with general comments on the presentation of the demand of modification, questions related to the completeness of the impact study, comments on methodological issues, and a description of the site in its current status. It discusses the permanent impacts on the environment (radio-ecological impacts on the natural environment, impacts on health, impacts related to waste management, non-radiological impacts on water, and impacts on biodiversity). It comments the means of control and monitoring. It proposes an analysis of the risk management study, and comments on non-technical abstracts. The authority then makes recommendations. It notably recommends a presentation of an assessment of this 'MOXing', notably in terms of liquid and gaseous releases in terms of contribution to fuel cycle closure and of plutonium usage. It indicates improvements and technical precision to be brought to this file, and criticizes the readability of the document

2011-01-01

382

Rapid trachoma assessment in kersa district, southwest ethiopia.  

UK PubMed Central (United Kingdom)

BACKGROUND: Trachoma is the leading cause of infectious blindness worldwide. Though trachoma can be treated with antibiotics (active trachoma) or surgery (trachomatous trichiasis), it is still endemic in most parts of Ethiopia. Despite the prevalence of this infectious disease in different parts of the country, district level data is lacking. This study was thus conducted to assess the prevalence estimate of trachoma and its risk factors in Kersa District, Southwest Ethiopia. METHODS: A community based cross sectional Rapid Assessment of Trachoma was conducted using a WHO guideline. Six sub-districts were selected from Kersa District based on primary high risk assessment and from each sub-district; 21-27 households were randomly selected. Active trachoma for children aged 1-9 years, trachomatous trichiasis for people above 15 years old and environmental risk factors for trachoma were assessed. Data were analyzed using SPSS version 16. RESULTS: The overall prevalence estimate of active trachoma was 25.2% (95% CI: 20.7-30.4%). Forty three percent of children had unclean faces, 11.5% of households had water source at more than half hour walking distance, 18.2% did not have functional latrine, and 95.3% of the households had solid waste disposal within a distance of 20 meters. Households with environmental risk factors were at an increased risk to active trachoma, but the association was not statistically significant (p>0.05). The prevalence estimate of trachomatous trichiasis inclusive of "trachoma suspects" was 4.5%. CONCLUSION: Trachoma is endemic in Kersa District with active trachoma being a public health problem in the studied sub-districts. Hence, SAFE strategy should be implemented.

Ejigu M; Kariuki MM; Ilako DR; Gelaw Y

2013-03-01

383

Prevalence of skin cancer in southwest of Iran  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction: Skin cancer is one of the most prevalent cancers in the world and is known as the first or second common malignancy in different parts of Iran. According to preventable nature of most types of skin cancers and because of the lack of data about this cancer in Khuzestan province, this study was done to evaluate the frequency of skin cancers in the southwest of Iran and its relationship to sun exposure.Materials and Methods: Data of demographic characteristics such as age, gender, type of cancer and its body location was extracted from pathologically confirmed Khuzestan Cancer Center which was during Mars2009-Mars 2010.Results: From 5201 of cancers recorded, 602 were of skin cancers (mean of age: 61y/o). All types of skin cancers were higher in men (n = 348, 56.8%, P = 0.03) and 40 years and older (P <0.001). Basal cell carcinoma (BCC) was seen in 424 patients (70.4%), squamous cell carcinoma (SCC) in 85 patients, and malignant melanoma in 22, and other skin cancers in 71 patients. Skin cancer type was statistically correlated to skin's topography and sunlightexposure (SCC and BCC were higher in sun-exposed areas (P<0.001).Conclusion: According to Khuzestan's geographic location, most days are sunny, and most of the peoplework outdoor (farmers or petroleum workers) and because of the great role of sunlight in skin cancer, we suggest more educational programs regarding using sun screens, sunglasses, suitable hats and cloths and avoiding from sun-exposure when direct sunlight is expected.

ValaviEhsan; Rafie Shahram; Pakseresht Parichehr; Siadat Sima

2013-01-01

384

Participatory assessment of the Toliara Bay reef fishery, southwest Madagascar  

Directory of Open Access Journals (Sweden)

Full Text Available In order to ensure the sustainable management of reef fisheries, it is necessary to obtain data about the effects of these fisheries on both fish resources and the ecosystems that sustain them. Ecosystem-based surveys provide this information, but are difficult to implement because of technical, financial and human resources requirements. In this regard participatory assessment methods have the potential to increase the amount of data collected at low cost, while taking advantage of local traditional ecological knowledge. In order to investigate the reef fishery of Toliara Bay, southwest Madagascar, we used participatory fish survey and interview data collected on site. These methods included: (i) monitoring of catch landings during six months by wholesale fish merchants, (ii) household surveys of fishing catch and effort and fish consumption conducted by school children, and (iii) semi-structured interviews of reef users. One thousand five hundred and eighty six fishing trips were sampled between September 2006 and February 2007, 326 households were surveyed by trained school children in January 2007, and 70 reef users were interviewed in July/August 2006. Data collected by participants have been compiled and compared to reference values when available, allowing an assessment of the sustainability of the reef fishery. The results of this study confirm the unsustainable nature of resource exploitation and underline the need for rapid management responses in order to reverse this trend. It also highlights the great potential of participatory assessment methods for gathering large amounts of relevant information on the status and evolution of the ecosystem upon which the fishery depends, while promoting education and awareness about the protection and sustainable use of natural resources.

Ambroise Brenier; Jocelyne Ferraris; Jamal Mahafina

2011-01-01

385

Evaluation of agricultural extension and delivery services in southwest Nigeria  

Directory of Open Access Journals (Sweden)

Full Text Available 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-requisite for rural development. Agricultural Extension is defined as system for the exchange of information and transfer of skills between farmers, extension workers and researchers for the purpose of assisting farmers to identify farming production problems: with the aim that farmers will adopt technological and socio-economically based solutions that will increase farm resource use efficiency, improve the management and conservation of natural resources and improve their living standards. It is achievable through an adult training process. Agricultural extension activities in Nigeria have developed from the largely regulatory body of the government’s rural administration with its main functions of ensuring the adoption of improved technologies. At the time of independence the major government agency charged with agricultural extension and most of the rural development functions were the Ministry of Agriculture which, continues, to reflect this major involvement in rural development. One of the most effective means of achieving increased agricultural productivity is through the use of modern farm inputs like fertilizers, improved high yielding seeds or seedlings, herbicides, pesticides, organic manure, as well as modern farm implements and equipment.

Ogunsumi L.O.; Abegunde B.O.

2011-01-01

386

Conclusions from clinical trials of the Southwest Oncology Group.  

Science.gov (United States)

Mature data from four clinical trials conducted by the Southwest Oncology Group from 1971 to 1978 for patients with all stages of Hodgkin's disease (HD) are reviewed in this paper. In the RAC #1 trial of stage I and II HD we demonstrated that involved-field radiotherapy plus six courses of MOPP chemotherapy improved relapse-free survival compared to standard radiotherapy alone (P = 0.12), especially in patients with B symptoms (P less than 0.03) or mediastinal disease (P = 0.08). However, at present, there is no significant difference in overall survival. In the CAR #1 study for patients with pathologic stage IIB, IIIA, and IIIB HD, we demonstrated that three or four courses of MOPP before radiotherapy produced a 90% complete remission (CR) rate, with 70% of the patients remaining free of disease at 5 years. In the CAR #2 study for patients with pathologic stage IIIA or IIIB disease, we demonstrated that chemotherapy alone (MOPP-bleomycin) was as effective as combined modality treatment (MOPP-bleomycin plus radiotherapy) in terms of CR rate (85% versus 89%, respectively), relapse-free survival, and survival. For advanced stages of HD we added doxorubicin to our MOPP-bleomycin schedule and demonstrated that MOP-BAP produced a 77% CR rate compared to 67% for MOPP-bleomycin (P = 0.10). Moreover, MOP-BAP produced consistently superior CR rates and survival in patients with more prognostically favorable presentations of HD. Our new ongoing study (MOPP #6) incorporates many of the concepts derived from these earlier clinical investigations. PMID:6176321

Jones, S E; Coltman, C A; Grozea, P N; DePersio, E J; Dixon, D O

1982-04-01

387

The Gambia River estuary: A reference point for estuarine fish assemblages studies in West Africa  

Science.gov (United States)

The Gambia River is one of the last aquatic ecosystems in West Africa that has not yet been affected by strong environmental changes and human disturbances. In contrast to the neighbouring Casamance and Sine Saloum estuaries, the Gambia estuary is free of major climatic perturbation and remains a “normal” estuary, with a salinity range from freshwater to 39. The present paper aims to study the spatial and seasonal variability of fish assemblages in this