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Sample records for estuarine sediment standard

  1. Distribution and partitioning of heavy metals in estuarine sediment cores and implications for the use of sediment quality standards

    Directory of Open Access Journals (Sweden)

    K. L. Spencer

    2002-01-01

    Full Text Available Total metal concentrations in surface sediments and historically contaminated sediments were determined in sediment cores collected from three estuaries (Thames, Medway and Blackwater in south-east England. The partitioning behaviour of metals in these sediments was also determined using a sequential extraction scheme. These data were then compared with sediment quality values (SQVs to determine the potential ecotoxicological risk to sediment dwelling organisms. When total metal concentrations in surface sediments are examined, no risk to biota in any of the estuaries is indicated. However, when historically contaminated sediments at depth are also considered, risks to biota are apparent and are greatest for the Thames, followed by the Medway and then the Blackwater. This suggests that regulatory authorities should examine vertical metal profiles, particularly in estuaries that are experiencing low sediment accumulation rates where historically contaminated sediments are in the shallow sub-surface zone and where erosion or dredging activities may take place. When metal partitioning characteristics are also considered, the risk to biota is comparable for the Medway and the Blackwater with the potentially bioavailable fraction presenting no ecotoxicological risk. Conversely, over 70% of metals are labile in the Thames Estuary sediments and toxic effects are probable. This suggests that the application of SQVs using total sediment metal concentrations may over- or under-estimate the risk to biota in geochemically dissimilar estuarine sediments. Keywords: sediment quality values, estuarine sediments, metal contamination, partitioning, sequential extraction

  2. Algal stabilisation of estuarine sediments

    International Nuclear Information System (INIS)

    1992-01-01

    The presence of benthic microalgae can increase the stability of intertidal sediments and influence sediment fluxes within an estuarine environment. Therefore the relative importance of algal stabilisation needs to be understood to help predict the effects of a tidal barrage. The biogenic stabilisation of intertidal estuarine sediments by epipelic diatom films and the macrophyte Vaucheria was studied at three sites on the Severn Estuary. The cohesive strength meter (CSM) was developed to measure surface critical shear stress with varied algal density. A number of techniques have been used to determine the general in situ erodibility of cohesive estuarine sediments. The measurements of sediment shear strength and critical erosion velocity were investigated. Field experiments were undertaken to investigate the effect of algae on binding sediments, and a predictive method for the assessment of sediment stabilisation by algal binding was developed. (author)

  3. Algal stabilisation of estuarine sediments

    International Nuclear Information System (INIS)

    1992-01-01

    The presence of benthic microalgae can increase the stability of intertidal sediments and influence sediment fluxes within an estuarine environment. Therefore the relative importance of algal stabilisation needs to be understood to help predict the effects of a tidal barrage. The objectives of this study are: to assess the significance of stabilisation of sediments by algae, in relation to the changes in hydrodynamic and sedimentological regimes arising from the construction of tidal power barrages; to identify a reliable and meaningful method of measuring the effectiveness, including duration, of algal binding on sediment stability, and to relate this method to other methods of measuring critical erosion velocity and sediment shear strength; to undertake a series of field experiments investigating the effect of algae on binding sediments and the parameters which could potentially influence such binding and to develop a predictive method for the assessment of sediment stabilisation by algal binding. This report contains plates, figures and tables. (author)

  4. Hydrocarbon pollution from marinas in estuarine sediments

    Science.gov (United States)

    Voudrias, Evangelos A.; Smith, Craig L.

    1986-03-01

    A measure of the impact of marinas on three Eastern Virginia estuarine creeks was obtained by a study of hydrocarbons in their sediments. Two of the creeks support considerable marine activity, including pleasure boat marinas, boat repair facilities, and commercial fishing operations. The third creek, which served as a control, is seldom used by boats, and is surrounded by marsh and woodland. Sediments from the creeks with marinas contained significantly higher levels of both aromatic and aliphatic hydrocarbons than did the control. Differences in the concentrations of certain oil-pollution indicators, such as the 17α,21β-hopane homologs and phytane, and low molecular weight aromatic hydrocarbons, are indicative of light petroleum fractions. Most of the aromatic hydrocarbons from all creeks, however, appear to have a pyrogenic origin. Although hydrocarbons from three probable origins (petroleum, pyrogenesis, and recent biosynthesis) were detected in all locations, the petroleum-derived and pyrogenic hydrocarbons were of only minor importance relative to the biogenic hydrocarbons in the control creek.

  5. Estuarine Facies Model Revisited: Conceptual Model of Estuarine Sediment Dynamics During Non-Equilibrium Conditions

    Science.gov (United States)

    Elliott, E. A.; Rodriguez, A. B.; McKee, B. A.

    2017-12-01

    Traditional models of estuarine systems show deposition occurs primarily within the central basin. There, accommodation space is high within the deep central valley, which is below regional wave base and where current energy is presumed to reach a relative minimum, promoting direct deposition of cohesive sediment and minimizing erosion. However, these models often reflect long-term (decadal-millennial) timescales, where accumulation rates are in relative equilibrium with the rate of relative sea-level rise, and lack the resolution to capture shorter term changes in sediment deposition and erosion within the central estuary. This work presents a conceptual model for estuarine sedimentation during non-equilibrium conditions, where high-energy inputs to the system reach a relative maximum in the central basin, resulting in temporary deposition and/or remobilization over sub-annual to annual timescales. As an example, we present a case study of Core Sound, NC, a lagoonal estuarine system where the regional base-level has been reached, and sediment deposition, resuspension and bypassing is largely a result of non-equilibrium, high-energy events. Utilizing a 465 cm-long sediment core from a mini-basin located between Core Sound and the continental shelf, a 40-year sub-annual chronology was developed for the system, with sediment accumulation rates (SAR) interpolated to a monthly basis over the 40-year record. This study links erosional processes in the estuary directly with sediment flux to the continental shelf, taking advantage of the highly efficient sediment trapping capability of the mini-basin. The SAR record indicates high variation in the estuarine sediment supply, with peaks in the SAR record at a recurrence interval of 1 year (+/- 0.25). This record has been compared to historical storm influence for the area. Through this multi-decadal record, sediment flushing events occur at a much more frequent interval than previously thought (i.e. annual rather than

  6. Tributyltin-resistant bacteria from estuarine and freshwater sediments.

    Science.gov (United States)

    Wuertz, S; Miller, C E; Pfister, R M; Cooney, J J

    1991-01-01

    Resistance to tributyltin (TBT) was examined in populations from TBT-polluted sediments and nonpolluted sediments from an estuary and from fresh water as well as in pure cultures isolated from those sediments. The 50% effective concentrations (EC50s) for populations were higher at a TBT-polluted freshwater site than at a site without TBT, suggesting that TBT selected for a TBT-resistant population. In contrast, EC50s were significantly lower for populations from a TBT-contaminated estuarine site than for those from a site without TBT, suggesting that other factors in addition to TBT determine whether populations become resistant. EC50s for populations from TBT-contaminated freshwater sediments were nearly 30 times higher than those for populations from TBT-contaminated estuarine sediments. We defined a TBT-resistant bacterium as one which grows on trypticase soy agar containing 8.4 microM TBT, a concentration which prevented the growth of 90% of the culturable bacteria from these sediments. The toxicity of TBT in laboratory media was influenced markedly by the composition of the medium and whether it was liquid or solid. Ten TBT-resistant isolates from estuarine sediments and 19 from freshwater sediments were identified to the genus level. Two isolates, each a Bacillus sp., may be the first gram-positive bacteria isolated from fresh water in the presence of a high concentration of TBT. There was a high incidence of resistance to heavy metals: metal resistance indices were 0.76 for estuarine isolates and 0.68 for freshwater isolates.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1746939

  7. Tributyltin-resistant bacteria from estuarine and freshwater sediments.

    OpenAIRE

    Wuertz, S; Miller, C E; Pfister, R M; Cooney, J J

    1991-01-01

    Resistance to tributyltin (TBT) was examined in populations from TBT-polluted sediments and nonpolluted sediments from an estuary and from fresh water as well as in pure cultures isolated from those sediments. The 50% effective concentrations (EC50s) for populations were higher at a TBT-polluted freshwater site than at a site without TBT, suggesting that TBT selected for a TBT-resistant population. In contrast, EC50s were significantly lower for populations from a TBT-contaminated estuarine s...

  8. Assessment of the ecotoxicity of urban estuarine sediment using benthic and pelagic copepod bioassays

    Directory of Open Access Journals (Sweden)

    Maria P. Charry

    2018-05-01

    Full Text Available Urban estuarine sediments are sinks to a range of contaminants of anthropogenic origin, and a key challenge is to characterize the risk of these compounds to receiving environments. In this study, the toxicity of urban estuarine sediments was tested using acute and chronic bioassays in the benthic harpacticoid Quinquelaophonte sp., and in the planktonic calanoid Gladioferens pectinatus, two New Zealand copepod species. The sediment samples from the estuary tributary sites significantly impacted reproduction in Quinquelaophonte sp. However, results from one of the estuary sites were not significantly different to those from the tributaries sites, suggesting that chemicals other than trace metals, polycyclic aromatic hydrocarbons and ammonia may be the causative stressors. Sediment elutriate samples had significant effects on reproductive endpoints in G. pectinatus, and on the induction of DNA damage in cells, as shown by the comet assay. The results indicate that sediment contamination at the Ahuriri Estuary has the potential to impact biological processes of benthic and pelagic organisms. The approach used provides a standardized methodology to assess the toxicity of estuarine sediments.

  9. Assessment of the ecotoxicity of urban estuarine sediment using benthic and pelagic copepod bioassays.

    Science.gov (United States)

    Charry, Maria P; Keesing, Vaughan; Costello, Mark; Tremblay, Louis A

    2018-01-01

    Urban estuarine sediments are sinks to a range of contaminants of anthropogenic origin, and a key challenge is to characterize the risk of these compounds to receiving environments. In this study, the toxicity of urban estuarine sediments was tested using acute and chronic bioassays in the benthic harpacticoid Quinquelaophonte sp., and in the planktonic calanoid Gladioferens pectinatus , two New Zealand copepod species. The sediment samples from the estuary tributary sites significantly impacted reproduction in Quinquelaophonte sp. However, results from one of the estuary sites were not significantly different to those from the tributaries sites, suggesting that chemicals other than trace metals, polycyclic aromatic hydrocarbons and ammonia may be the causative stressors. Sediment elutriate samples had significant effects on reproductive endpoints in G. pectinatus , and on the induction of DNA damage in cells, as shown by the comet assay. The results indicate that sediment contamination at the Ahuriri Estuary has the potential to impact biological processes of benthic and pelagic organisms. The approach used provides a standardized methodology to assess the toxicity of estuarine sediments.

  10. Microbial Formation of Ethane in Anoxic Estuarine Sediments

    OpenAIRE

    Oremland, Ronald S.

    1981-01-01

    Estuarine sediment slurries produced methane and traces of ethane when incubated under hydrogen. Formation of methane occurred over a broad temperature range with an optimum above 65°C. Ethane formation had a temperature optimum at 40°C. Formation of these two gases was inhibited by air, autoclaving, incubation at 4 and 80°C, and by the methanogenic inhibitor, 2-bromoethanesulfonic acid. Ethane production was stimulated by addition of ethylthioethanesulfonic acid, and production from ethylthi...

  11. VARIATIONS IN THE SPECTRAL PROPERTIES OF FRESHWATER AND ESTUARINE CDOM CAUSED BY PARTITIONING ONTO RIVER AND ESTUARINE SEDIMENTS

    Science.gov (United States)

    The optical properties and geochemical cycling of chromophoric dissolved organic matter (CDOM) are altered by its sorption to freshwater and estuarine sediments. Measured partition coefficients (Kp) of Satilla River (Georgia) and Cape Fear River estuary (North Carolina) CDOM ran...

  12. Lead distribution in coastal and estuarine sediments around India

    Digital Repository Service at National Institute of Oceanography (India)

    Chakraborty, S.; Chakraborty, P.; Nath, B.N.

    . Trace element geochemical associations in the Arabian Gulf. Mar. Pollut. Bull. 17, 353–356. doi:10.1016/0025-326X(86)90247-X Achyuthan, H., Richardmohan, D., Srinivasalu, S., 2002a. Trace metals concentrations in the sediment cores of estuary... in the coastal sediment of chennai coast. IIOAB J. 3, 12–18. Ray, A.K., Tripathy, S.C., Patra, S., Sarma, V. V, 2006. Assessment of Godavari estuarine mangrove ecosystem through trace metal studies. Environ. Int. 32, 219–223. Reddy, M.S., Basha, S., Sravan...

  13. Changes in metal contamination levels in estuarine sediments around India – An assessment

    Digital Repository Service at National Institute of Oceanography (India)

    Chakraborty, P.; Ramteke, D.; Chakraborty, S.; Nath, B.N.

    provides managers and decision-makers of environmental protection agency with a better scientific understanding for decision-making in controlling metal pollution in estuarine sediments around India....

  14. Anaerobic oxidation of acetylene by estuarine sediments and enrichment cultures

    International Nuclear Information System (INIS)

    Culbertson, C.W.; Zehnder, A.J.B.; Oremland, R.S.

    1981-01-01

    Acetylene disappeared from the gas phase of anaerobically incubated estuarine sediment slurries, and loss was accompanied by increased levels of carbon dioxide. Acetylene loss was inhibited by chloroamphenicol, air, and autoclaving. Addition of 14 C 2 H 2 to slurries resulted in the formation of 14 CO 2 and the transient appearance of 14 C-soluble intermediates, of which acetate was a major component. Acetylene oxidation stimulated sulfate reduction; however, sulfate reduction was not required for the loss of C 2 H 2 to occur. Enrichment cultures were obtained which grew anaerobically at the expense of C 2 H 2

  15. Manganese and iron as oxygen carriers to anoxie estuarine sediment

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    Brayner, F. M. M.; Matvienko, B.

    2003-05-01

    We studied the concentration of a series of transition metals including Mn and Fe in an estuarine fishpond. The pond is situated at latitude 8°10'S and longitude 34°55'W, in the Capibaribe River estuary, within the Recife city boundaries, which is located in Pernambuco, a state of the Brazilian Northeast Pond area is 1.5 ha and it bas a 0.5 m depth. It is separated from the river by dikes. Water temperature at 28° C is stable throughout the year. Light breezes keep the water aerated, but intense ongoing decomposition makes the sediment anoxie. The area, originally of mangrove type, has been changed by antropic action on its fauna and vegetation. The study focuses on changes in behaviour of heavy metals. Samples of bottom sediments wore collected by Eckman dredge sediment sampler and total metal concentration was determined by the lithium borate fusion method. Water, recent sediment, and consolidated sediment were examined in this fishpond where Mn and Fe are brought in periodically by water and then gradually go into the sediment at respective rates of 10.52 and 1332 mg m^{-2}a^{-1}. Strong bioturbation re-suspends sediment while simultaneously re-dissolution of these ions is going on fhrough reduction in the anoxie sédiment. As soluble species these ions migrate from sediment to water and are there continually oxidized by dissolved oxygen, becoming insoluble. With their precipitation, chemically bound oxygen is carried down to the sediment, constituting a parallel channel of transport in addition to migration into the sediment bydiffusion of the oxygen dissolved in the water. The estimated flow rates are 3.25 and 76 mg O2 m^{-2}a^{-1} due to Mn and Fe respectively. The rates were established using natural silicon as a tracer.

  16. Estuarine abandoned channel sedimentation rates record peak fluvial discharge magnitudes

    Science.gov (United States)

    Gray, A. B.; Pasternack, G. B.; Watson, E. B.

    2018-04-01

    Fluvial sediment deposits can provide useful records of integrated watershed expressions including flood event magnitudes. However, floodplain and estuarine sediment deposits evolve through the interaction of watershed/marine sediment supply and transport characteristics with the local depositional environment. Thus extraction of watershed scale signals depends upon accounting for local scale effects on sediment deposition rates and character. This study presents an examination of the balance of fluvial sediment dynamics and local scale hydro-geomorphic controls on alluviation of an abandoned channel in the Salinas River Lagoon, CA. A set of three sediment cores contained discrete flood deposits that corresponded to the largest flood events over the period of accretion from 1969 to 2007. Sedimentation rates scaled with peak flood discharge and event scale sediment flux, but were not influenced by longer scale hydro-meteorological activities such as annual precipitation and water yield. Furthermore, the particle size distributions of flood deposits showed no relationship to event magnitudes. Both the responsiveness of sedimentation and unresponsiveness of particle size distributions to hydro-sedimentological event magnitudes appear to be controlled by aspects of local geomorphology that influence the connectivity of the abandoned channel to the Salinas River mainstem. Well-developed upstream plug bar formation precluded the entrainment of coarser bedload into the abandoned channel, while Salinas River mouth conditions (open/closed) in conjunction with tidal and storm surge conditions may play a role in influencing the delivery of coarser suspended load fractions. Channel adjacent sediment deposition can be valuable records of hydro-meteorological and sedimentological regimes, but local depositional settings may dominate the character of short term (interdecadal) signatures.

  17. Copper effects on bacterial activity of estuarine silty sediments

    Science.gov (United States)

    Almeida, Adelaide; Cunha, Ângela; Fernandes, Sandra; Sobral, Paula; Alcântara, Fernanda

    2007-07-01

    Bacteria of silty estuarine sediments were spiked with copper to 200 μg Cu g -1 dry weight sediment in order to assess the impact of copper on bacterial degradation of organic matter and on bacterial biomass production. Bacterial density was determined by direct counting under epifluorescence microscopy and bacterial production by the incorporation of 3H-Leucine. Leucine turnover rate was evaluated by 14C-leucine incorporation and ectoenzymatic activities were estimated as the hydrolysis rate of model substrates for β-glucosidase and leucine-aminopeptidase. The presence of added copper in the microcosms elicited, after 21 days of incubation, generalised anoxia and a decrease in organic matter content. The non-eroded surface of the copper-spiked sediment showed, when compared to the control, a decrease in bacterial abundance and significant lower levels of bacterial production and of leucine turnover rate. Bacterial production and leucine turnover rate decreased to 1.4% and 13% of the control values, respectively. Ectoenzymatic activities were also negatively affected but by smaller factors. After erosion by the water current in laboratory flume conditions, the eroded surface of the control sediment showed a generalised decline in all bacterial activities. The erosion of the copper-spiked sediment showed, however, two types of responses with respect to bacterial activities at the exposed surface: positive responses of bacterial production and leucine turnover rate contrasting with slight negative responses of ectoenzymatic activities. The effects of experimental erosion in the suspended cells were also different in the control and in the copper-spiked sediment. Bacterial cells in the control microcosm exhibited, when compared to the non-eroded sediment cells, decreases in all activities after the 6-h suspension. The response of the average suspended copper-spiked sediment cell differed from the control by a less sharp decrease in ectoenzymatic activities and

  18. RELEVANCE OF ROOTED VASCULAR PLANTS AS INDICATORS OF ESTUARINE SEDIMENT QUALITY

    Science.gov (United States)

    Toxicity assessments and numerical quality assessment guidelines for estuarine sediments are rarely based on information for aquatic plants. The effect of this lack of information on contaminated sediment evaluations is largely unknown. For this reason, the toxicities of whole se...

  19. Significance of antifouling paint flakes to the distribution of dichlorodiphenyltrichloroethanes (DDTs) in estuarine sediment

    International Nuclear Information System (INIS)

    Wu, Chen-Chou; Bao, Lian-Jun; Tao, Shu; Zeng, Eddy Y.

    2016-01-01

    Recently published literature indicated that dichlorodiphenyltrichloroethane (DDT)-containing antifouling paint flakes were heterogeneously distributed within estuarine sediments. However, the significance of antifouling paint flakes in the fate and transport of DDT compounds and other organic pollutants in estuarine sediment is yet to be adequately addressed. To fill this knowledge gap, estuarine sediment and paint flakes from cabin and boat surfaces were collected from a fishery base in Guangdong Province of South China and analyzed for DDT compounds. Coarse fractioned samples collected from the vicinity of boat maintenance facilities contained appreciable amounts of colorful particles, which were identified as paint flakes by Fourier transform infrared spectroscopy. The highest concentrations of DDXs (sum of DDTs and its metabolites) occurred in the heavy-density (>1.7 g cm"−"3) fraction of coarse-size (200–2000 μm) sediments from near the boat maintenance facilities, suggesting the importance of paint flakes in the distribution pattern of “hot spots” in estuarine sediment. Moreover, the desorption rates of DDT compounds from paint flakes and the heavy-density fraction of coarse-size sediment were both extremely slow. Apparently, unevenly distributed paint flakes in sediment can artificially inflate the sorption capacity of heavy-density sediment for DDT compounds, and therefore can substantially change the environmental fate and behavior of hydrophobic organic chemicals in estuarine sediment. Finally, commonly used source diagnostic indices of DDT compounds were mostly grain-size and density dependent in sediment, as a result of the occurrence of paint flakes, which may strongly compromise the outcome of any source diagnostics efforts. - Highlights: • Concentrations of DDTs were elevated in coarse and high-density fractions. • The desorption rates of DDTs from coarse and high-density fraction were extreme slow. • DDTs-containing antifouling

  20. Relationship between benthic foraminifera and sediment in the estuarine complex of Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Dalal, S.G.

    Two indices of community association were used to elucidate the relationship between changes in species composition of benthic foraminifera and changes in the grain size composition of the sediment in estuarine complex of Goa. The degree...

  1. Effect of sediment properties on the sorption of C12-2-LAS in marine and estuarine sediments

    NARCIS (Netherlands)

    Rico Rico, A.; Temara, A.; Behrends, T.; Hermens, J.L.M.

    2009-01-01

    Linear alkylbenzene sulfonates (LAS) are anionic high production volume surfactants used in the manufacture of cleaning products. Here, we have studied the effect of the characteristics of marine and estuarine sediments on the sorption of LAS. Sorption experiments were performed with single sediment

  2. The flux of 226Ra from estuarine and continental shelf sediments

    International Nuclear Information System (INIS)

    Li, Y.H.; Mathieu, G.; Biscaye, P.; Simpson, H.J.

    1977-01-01

    A pronounced desorption phenomenon of 226 Ra from sediment was observed in the Hudson River estuary. Mass balance calculations indicate that the desorption of 226 Ra from the river-borne sediment in estuarine environment is an important source of 226 Ra to the oceans. (Auth.)

  3. MICROBIAL DIVERSITY IN SURFACE SEDIMENTS: A COMPARISON OF TWO ESTUARINE CONTINUUMS

    Science.gov (United States)

    The microbial diversity in estuarine sediments of the Altamaha and Savannah Rivers in Georgia were compared temporally and spatially using phospholipid fatty acid (PLFA) analysis. Surface sediment samples collected along a salinity gradient were also analyzed for ATP, TOC, and C ...

  4. A study of lead and cadmium speciation in some estuarine and coastal sediments

    Digital Repository Service at National Institute of Oceanography (India)

    Chakraborty, P.; Babu, P.V.R.; Sarma, V.V.

    ., Campbell, M., Weir, E., 2002, Identifying and managing adverse environmental health effects: 3. Lead exposure. CMAJ 166, 1287–1292. Stohs, S.J., Bagchi, D., 1995, Oxidative mechanisms in the toxicity of metal ions. Free Radical Biology and Medicine, 18... the kinetic speciation of Pb and Cd in the coastal and estuarine sediments of Bay of Bengal. Consider sediments samples of n different components, in which each component, M-Sediment i , exists in equilibrium with its dissociation products: the free metal...

  5. In Situ Enhancement of Anaerobic Microbial Dechlorination of Polychlorinated Dibenzo-p-dioxins and Dibenzofurans in Marine and Estuarine Sediments

    National Research Council Canada - National Science Library

    Haeggblom, Max M; Fennell, Donna E; Kerkhof, Lee J

    2006-01-01

    ... that is associated with dredging, and decrease the cost of sediment management. Reductive dehalogenation is a promising mechanism for the removal of toxic organohalides from estuarine and marine sediments...

  6. An evaluation of contaminated estuarine sites using sediment quality guidelines and ecological assessment methodologies.

    Science.gov (United States)

    Fulton, M; Key, P; Wirth, E; Leight, A K; Daugomah, J; Bearden, D; Sivertsen, S; Scott, G

    2006-10-01

    Toxic contaminants may enter estuarine ecosystems through a variety of pathways. When sediment contaminant levels become sufficiently high, they may impact resident biota. One approach to predict sediment-associated toxicity in estuarine ecosystems involves the use of sediment quality guidelines (ERMs, ERLs) and site-specific contaminant chemistry while a second approach utilizes site-specific ecological sampling to assess impacts at the population or community level. The goal of this study was to utilize an integrated approach including chemical contaminant analysis, sediment quality guidelines and grass shrimp population monitoring to evaluate the impact of contaminants from industrial sources. Three impacted sites and one reference site were selected for study. Grass shrimp populations were sampled using a push-netting approach. Sediment samples were collected at each site and analyzed for metals, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and pesticides. Contaminant levels were then compared to sediment quality guidelines. In general, grass shrimp population densities at the sites decreased as the ERM quotients increased. Grass shrimp densities were significantly reduced at the impacted site that had an ERM exceedance for chromium and the highest Mean ERM quotient. Regression analysis indicated that sediment chromium concentrations were negatively correlated with grass shrimp density. Grass shrimp size was reduced at two sites with intermediate levels of contamination. These findings support the use of both sediment quality guidelines and site-specific population monitoring to evaluate the impacts of sediment-associated contaminants in estuarine systems.

  7. Comparison of estuarine sediment record with modelled rates of sediment supply from a western European catchment since 1500

    Science.gov (United States)

    Poirier, Clément; Poitevin, Cyril; Chaumillon, Éric

    2016-09-01

    Marine and estuarine sediment records reporting impacts of historical land use changes exist worldwide, but they are rarely supported by direct quantified evidence of changes in denudation rates on the related catchments. Here we implement a spatially-resolved RUSLE soil erosion model on the 10 000 km2 Charente catchment (France), supplied with realistic scenarios of land-cover and climate changes since 1500, and compare the results to a 14C-dated estuarine sediment record. Despite approximations, the model correctly predicts present-day Charente river sediment load. Back-cast modelling suggests that the Charente catchment is an interesting case where the sediment supply did not change despite increase in soil erosion resulting from 18th-century deforestation because it was mitigated by drier climate during the same period. Silt-sand alternations evidenced in the sediment record were correlated with sub-decadal rainfall variability.

  8. Role of Phragmites australis (common reed) for heavy metals phytoremediation of estuarine sediments.

    Science.gov (United States)

    Cicero-Fernández, Diego; Peña-Fernández, Manuel; Expósito-Camargo, Jose A; Antizar-Ladislao, Blanca

    2016-01-01

    The ability of Phragmites australis to take up heavy metals (Co, Ni, Mo, Cd, Pb, Cr, Cu, Fe, Mn, Zn, and Hg) and other trace elements (As, Se, Ba), from estuarine sediments was investigated using a pilot plant experimental approach. Bioaccumulation (BCF) and translocation factors (TF) were calculated in vegetative and senescence periods for two populations of P. australis, from contaminated (MIC) and non-contaminated (GAL) estuarine sediments, respectively, both growing in estuarine contaminated sediment (RIA) from ría del Carmen y Boo, Santander Bay, Spain. The highest BCF values were obtained for Ni (0.43), Ba (0.43) Mo (0.36), Cr (0.35), and Cd (0.31) for plants collected from site GAL following the senescence period. The highest BCF values recorded for plants collected from MIC following the senescence period were for Mo (0.22) and Cu (0.22). Following senescence, plants collected from GAL and MIC presented TF>1 for Ni, Mo, Se, and Zn, and in addition plants collected from MIC presented TF>1 for Ba, Cr, and Mn. A substantial increase of Micedo's rhizosphere, six times higher than Galizano's rhizosphere, suggested adaptation to contaminated sediment. The evaluated communities of P. australis demonstrated their suitability for phytoremediation of heavy metals contaminated estuarine sediments.

  9. Seasonal variations in suspended-sediment dynamics in the tidal reach of an estuarine tributary

    Science.gov (United States)

    Downing-Kunz, Maureen A.; Schoellhamer, David H.

    2013-01-01

    Quantifying sediment supply from estuarine tributaries is an important component of developing a sediment budget, and common techniques for estimating supply are based on gages located above tidal influence. However, tidal interactions near tributary mouths can affect the magnitude and direction of sediment supply to the open waters of the estuary. We investigated suspended-sediment dynamics in the tidal reach of Corte Madera Creek, an estuarine tributary of San Francisco Bay, using moored acoustic and optical instruments. Flux of both water and suspended-sediment were calculated from observed water velocity and turbidity for two periods in each of wet and dry seasons during 2010. During wet periods, net suspended-sediment flux was seaward; tidally filtered flux was dominated by the advective component. In contrast, during dry periods, net flux was landward; tidally filtered flux was dominated by the dispersive component. The mechanisms generating this landward flux varied; during summer we attributed wind–wave resuspension in the estuary and subsequent transport on flood tides, whereas during autumn we attributed increased spring tide flood velocity magnitude leading to local resuspension. A quadrant analysis similar to that employed in turbulence studies was developed to summarize flux time series by quantifying the relative importance of sediment transport events. These events are categorized by the direction of velocity (flood vs. ebb) and the magnitude of concentration relative to tidally averaged conditions (relatively turbid vs. relatively clear). During wet periods, suspended-sediment flux was greatest in magnitude during relatively turbid ebbs, whereas during dry periods it was greatest in magnitude during relatively turbid floods. A conceptual model was developed to generalize seasonal differences in suspended-sediment dynamics; model application to this study demonstrated the importance of few, relatively large events on net suspended-sediment flux

  10. Aggregation, sedimentation, dissolution and bioavailability of quantum dots in estuarine systems.

    Science.gov (United States)

    To understand their fate and transport in estuarine systems, the aggregation, sedimentation, and dissolution of CdSe quantum dots (QDs) in seawater were investigated. Hydrodynamic size increased from 40 to 60 nm to >1 mm within 1 h in seawater, and the aggregates were highly p...

  11. Estuarine morphodynamic adaptation to sediment supply and human activities : A case study of turbidity maximum

    NARCIS (Netherlands)

    Zhu, C.; Guo, L; Tian, B.; He, Q; Wang, Zhengbing

    2017-01-01

    Estuarine morphodynamics undergo significant changes due to declined sediment supply from river, rising sea-level, and human interferences (Syvitski and Saito, 2007; Syvitski et al., 2009). The Yangtze Estuary is such a case whose decadal morphodynamic evolution was broadly examined. It was

  12. Uranium geochemistry in estuarine sediments: Controls on removal and release processes

    International Nuclear Information System (INIS)

    Barnes, C.E.; Cochran, J.K.

    1993-01-01

    Porewater uranium profiles from Long Island Sound (LIS) and Amazon shelf sediments and LIS sediment incubation experiments indicate that both removal and release processes control U geochemistry in estuarine sediments. Release of U from sediments occurs in association with Fe reduction. A correlation between U and Fe (and Mn) observed in sediment incubation experiments suggests that there is release of U from Fe-Mn-oxides as they are reduced, consistent with data from the Amazon shelf. In both sediment porewater profiles (LIS and Amazon) and sediment incubation experiments (LIS), there is removal of U from porewater under conditions of sulfate reduction. Sediment incubation experiments indicate that the removal rate is first-order with respect to U concentration, and the rate constant is linearly correlated to sulfate reduction rates. The link between U removal and sulfate reduction (a measure of diagenetic microbial activity) is consistent with a microbial mediation of U reduction. The diffusion flux of U into LIS sediments is estimated from porewater profiles. The inclusion of this estuarine removal term in the oceanic U balance increases the importance of the sediment sink. 62 refs., 12 figs., 2 tabs

  13. Evaluation of Sediment Trap Efficiency in an Estuarine Environment

    National Research Council Canada - National Science Library

    Stoddard, Daniel

    2001-01-01

    .... A second trap of same dimensions was also incorporated 420 m upstream. Trap efficiency was calculated as a sediment removal ratio, or the percentage by which influent sediment load to the trap is reduced in the effluent load from the trap...

  14. Effects-based spatial assessment of contaminated estuarine sediments from Bear Creek, Baltimore Harbor, MD, USA.

    Science.gov (United States)

    Hartzell, Sharon E; Unger, Michael A; McGee, Beth L; Wilson, Sacoby M; Yonkos, Lance T

    2017-10-01

    Estuarine sediments in regions with prolonged histories of industrial activity are often laden to significant depths with complex contaminant mixtures, including trace metals and persistent organic pollutants. Given the complexity of assessing risks from multi-contaminant exposures, the direct measurement of impacts to biological receptors is central to characterizing contaminated sediment sites. Though biological consequences are less commonly assessed at depth, laboratory-based toxicity testing of subsurface sediments can be used to delineate the scope of contamination at impacted sites. The extent and depth of sediment toxicity in Bear Creek, near Baltimore, Maryland, USA, was delineated using 10-day acute toxicity tests with the estuarine amphipod Leptocheirus plumulosus, and chemical analysis of trace metals and persistent organic pollutants. A gradient of toxicity was demonstrated in surface sediments with 21 of 22 tested sites differing significantly from controls. Effects were most pronounced (100% lethality) at sites proximate to a historic industrial complex. Sediments from eight of nine core samples to depths of 80 cm were particularly impacted (i.e., caused significant lethality to L. plumulosus) even in locations overlain with relatively non-toxic surface sediments, supporting a conclusion that toxicity observed at the surface (top 2 cm) does not adequately predict toxicity at depth. In seven of nine sites, toxicity of surface sediments differed from toxicity at levels beneath by 28 to 69%, in five instances underestimating toxicity (28 to 69%), and in two instances overestimating toxicity (44 to 56%). Multiple contaminants exceeded sediment quality guidelines and correlated positively with toxic responses within surface sediments (e.g., chromium, nickel, polycyclic aromatic hydrocarbon (PAH), total petroleum hydrocarbon). Use of an antibody-based PAH biosensor revealed that porewater PAH concentrations also increased with depth at most sites. This

  15. Holocene estuarine sediments as a source of arsenic in Pleistocene groundwater in suburbs of Hanoi, Vietnam

    Science.gov (United States)

    Kuroda, Keisuke; Hayashi, Takeshi; Funabiki, Ayako; Do, An Thuan; Canh, Vu Duc; Nga, Tran Thi Viet; Takizawa, Satoshi

    2017-06-01

    Groundwater pollution by arsenic is a major health threat in suburban areas of Hanoi, Vietnam. The present study evaluates the effect of the sedimentary environments of the Pleistocene and Holocene deposits, and the recharge systems, on the groundwater arsenic pollution in Hanoi suburbs distant from the Red River. At two study sites (Linh Dam and Tai Mo communes), undisturbed soil cores identified a Pleistocene confined aquifer (PCA) and Holocene unconfined aquifer (HUA) as major aquifers, and Holocene estuarine and deltaic sediments as an aquitard layer between the two aquifers. The Holocene estuarine sediments (approximately 25-40 m depth, 9.6-4.8 cal ka BP) contained notably high concentrations of arsenic and organic matter, both likely to have been accumulated by mangroves during the Holocene sea-level highstand. The pore waters in these particular sediments exhibited elevated levels of arsenic and dissolved organic carbon. Arsenic in groundwater was higher in the PCA (25-94 μg/L) than in the HUA (5.2-42 μg/L), in both the monitoring wells and neighboring household tubewells. Elevated arsenic concentration in the PCA groundwater was likely due to vertical infiltration through the arsenic-rich and organic-matter-rich overlying Holocene estuarine sediments, caused by massive groundwater abstraction from the PCA. Countermeasures to prevent arsenic pollution of the PCA groundwater may include seeking alternative water resources, reducing water consumption, and/or appropriate choice of aquifers for groundwater supply.

  16. Elemental analysis in bed sediment samples of Karnafuli estuarine zone in the Bay of Bengal by instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Molla, N.I.; Hossain, S.M.; Basunia, S.; Miah, R.U.; Rahman, M.; Sikder, D.H.; Chowdhury, M.I.

    1997-01-01

    The concentration of rare earths and other elements have been determined in the bed sediment samples of Karnafuli estuarine zone in the Bay of Bengal by instrumental neutron activation analysis (INAA). The samples and the standards soil-5, soil-7, coal fly ash and pond sediment were prepared and simultaneously irradiated for short and long time at the TRIGA Mark-II research reactor facility of Atomic Energy Research Establishment, Savar, Dhaka. The maximum thermal neutron flux was of the order of 10 13 n x cm -2 x s -1 . After irradiation the radioactivity of the product nuclides was measured by using a high resolution high purity germanium detector system. Analysis of γ-ray spectra and quantitative analysis of the elemental concentration were done via the software GANAAS. It has been possible to determine the concentration level of 27 elements including the rare earths La, Ce, Sm, Eu, Tb, Dy and Yb and uranium and thorium. (author)

  17. Observations of Lower Mississippi River Estuarine Dynamics: Effects of the Salt Wedge on Sediment Deposition

    Science.gov (United States)

    Ramirez, M. T.; Allison, M. A.

    2017-12-01

    The lowermost Mississippi River is subject to salt-wedge estuarine conditions during seasonally low flow, when seaward flow is unable to overcome density stratification. Previous studies in the Mississippi River salt wedge have shown the deposition of a fine sediment layer accumulating several mm/day beneath the reach where the salt wedge is present. Field studies were conducted during low flow in 2012-2015 utilizing ADCP, CTD, LISST, and physical samples to observe the physics of the salt wedge reach and to calculate rates and character of sediment trapping beneath the salt wedge. The field observations were summarized using a two-layer box-model representation of the reach to calculate water and sediment budgets entering, exiting, and stored within the reach. The salt wedge reach was found to be net depositional at rates up to 1.8 mm/day. The mechanism for transferring sediment mass from the downstream-flowing fluvial layer to the upstream-flowing marine layer appears to be flocculation, evidenced in LISST data by a spike in sediment particle diameters at the halocline. Applying reach-averaged rates of sediment trapping to a time-integrated model of salt-wedge position, we calculated annual totals ranging from 0.025 to 2.2 million tons of sediment deposited beneath the salt wedge, depending on salt-wedge persistence and upstream extent. Most years this seasonal deposit is remobilized during spring flood following the low-flow estuarine season, which may affect the timing of sediment delivery to the Gulf of Mexico, as well as particulate organic carbon, whose transport trajectory mirrors that of mineral sediment. These results are also relevant to ongoing dredging efforts necessary to maintain the economically-important navigation pathway through the lower Mississippi River, as well as planned efforts to use Mississippi River sedimentary resources to build land in the degrading Louisiana deltaic coast.

  18. Growth and decline of shoreline industry in Sydney estuary (Australia) and influence on adjacent estuarine sediments.

    Science.gov (United States)

    Birch, G F; Lean, J; Gunns, T

    2015-06-01

    Sydney estuary (Australia), like many urbanised waterways, is degraded due to an extended history of anthropogenic activity. Two major sources of contamination to this estuary are discharge by former shoreline industries and historic and contemporary catchment stormwater. The objectives of the present study were to document changes in shoreline land use from European settlement to the present day and determine the influence of this trend on the metal content of adjacent estuarine sediments. Temporal analysis of land use for seven time horizons between 1788 and 2010 showed rapid expansion of industry along much of the Sydney estuary foreshore soon after European settlement due to the benefits of easy and inexpensive access and readily available water for cooling and power. Shoreline industry attained maximum development in 1978 (32-km length) and declined rapidly to the present-day (9-km length) through redevelopment of industrial sites into medium- to high-density, high-value residential housing. Cores taken adjacent to 11 long-term industrial sites showed that past industrial practices contributed significantly to contamination of estuarine sediment. Subsurface metal concentrations were up to 35 times that of present-day surface sediment and over 100 times greater than natural background concentrations. Sedimentation rates for areas adjacent to shoreline industry were between 0.6 and 2.5 cm/year, and relaxation times were estimated at 50 to 100 years. Natural relaxation and non-disturbance of sediments may be the best management practice in most locations.

  19. Iron ore pollution in Mandovi and Zuari estuarine sediments and its fate after mining ban.

    Science.gov (United States)

    Kessarkar, Pratima M; Suja, S; Sudheesh, V; Srivastava, Shubh; Rao, V Purnachandra

    2015-09-01

    Iron ore was mined from the banded iron formations of Goa, India, and transported through the Mandovi and Zuari estuaries for six decades until the ban on mining from September 2012. Here we focus on the environmental magnetic properties of sediments from the catchment area, upstream and downstream of these estuaries, and adjacent shelf during peak mining time. Magnetic susceptibility (χ lf) and saturation isothermal remanent magnetization (SIRM) values of sediments were highest in upstream (catchment area and estuaries), decreased gradually towards downstream (catchment area and estuaries), and were lowest on the adjacent shelf. The χ lf values of the Mandovi estuary were two to fourfold higher than those in the Zuari. The sediments of these two estuaries after the mining ban showed enrichment of older magnetite and sharp decrease in the SIRM values. Although the input of ore material has been reduced after mining ban, more flushing of estuarine sediments is required for healthier environment.

  20. Transport of Gas and Solutes in Permeable Estuarine Sediments

    Science.gov (United States)

    2013-09-30

    Sea to Coast Connectivity in the Eastern Gulf of Mexico ” $203,471 (Huettel funds), E. Chassignet (PI), M. Huettel (one of several Co-PIs), we...However, in many shelf areas the depth, sufficient light reaching the sea floor will likely be less than 25 m due to water turbidity . The water in our...biogeochemical reactions. As crude oil from the recent oil spill in the Gulf and phytoplankton affect the sediment in the shallow nearshore zone, this project is

  1. Geochemical Screening of Contaminated Marine and Estuarine Sediments

    Science.gov (United States)

    Kruge, M. A.

    2004-05-01

    Waterways near urban centers have been subject to pollution by human activities for centuries. This process greatly intensified with the advent of the Industrial Revolution and the attendant exponential population increase in coastal areas. The co-occurrence of port facilities for ocean-going vessels, large factories, major power generating stations, dense automotive transportation networks, and massive wastewater outfalls, all in compact geographical areas, has produced severe environmental stress. In recent decades, the growing awareness of the seriousness of coastal urban environmental degradation has inspired intensive efforts at pollution prevention and remediation. To better understand pollution dynamics over time in an aquatic urban setting, a program of intensive sampling and analysis leading to the creation of geographic information systems (GIS) would be desirable. Chemical evaluation of sediments for pollution remains a costly and time-consuming procedure, particularly for organic analysis. Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) offers a practical alternative for rapid, inexpensive molecular organic analysis, simply employing milligram quantities of dry, whole sediment. The compounds detected comprise an information-rich mixture of thermally extractable components and the products of the thermal decomposition of (bio)polymers present in the sample. These include PAHs, petroleum-derived hopanes, organonitrogen compounds, and linear alkylbenzenes, as illustrated with examples from Long Island Sound and the Passaic River (USA) and Barcelona harbor (Spain).

  2. The fate of technetium in reduced estuarine sediments: Combining direct and indirect analyses

    International Nuclear Information System (INIS)

    Burke, Ian T.; Livens, Francis R.; Lloyd, Jonathan R.; Brown, Andrew P.; Law, Gareth T.W.; McBeth, Joyce M.; Ellis, Beverley L.; Lawson, Richard S.; Morris, Katherine

    2010-01-01

    Technetium-99 is an important fission product in radioactive wastes. As Tc(VII)O 4 - , Tc is highly mobile in oxic environments but, under reducing conditions, Tc becomes strongly associated with sediments as hydrous Tc(IV)O 2 like phases. In order to further examine the behaviour of Tc over a range of concentrations in estuarine sediments, anoxic incubation experiments were combined with a range of direct (transmission electron microscopy and gamma camera imaging) and indirect (incubation experiments and chemical extractions) experimental techniques. When TcO 4 - was incubated in sediment microcosms at micro-molar (10 -6 mol L -1 ) concentrations, >99% TcO 4 - was removed from solution over the course of 36 days in systems undergoing active microbial Fe(III)-reduction. By contrast, when spiked into pre-reduced estuarine sediments that were predominantly Fe(III)-reducing (incubated for 60 days) or SO 4 2- reducing (incubated for 270 days), >99% TcO 4 - was removed from solution in under 10 min in both microbially active and heat sterilised systems. Chemical extraction techniques showed that 70 ± 3% of Tc bound to sediments was remobilised when sediments were exposed to the first strong oxidant (H 2 O 2 ) in the extraction scheme. At higher Tc concentrations (∼0.05 mol kg -1 of sediment) scanning transmission electron microscopy, combined with energy dispersive X-ray mapping, was used to examine the associations of Tc in sediments. At these concentrations, Tc was localised and co-associated with nanometre size Fe(II)-rich particles, consistent with the hypothesis that removal of Tc may be controlled by reduction of Tc(VII) to Tc(IV) by biogenic Fe(II) in sediments. In addition, gamma camera imaging with the γ-emitting 99m TcO 4 - (half-life 6 h) at pico-molar (10 -12 mol L -1 ) concentrations, was used to visualise the interaction of Tc in sediments at very low concentrations. Here, over the course of 24 h the scavenging of Tc to SO 4 2- reducing sediments was

  3. Associations between dioxins/furans and dioxin-like PCBs in estuarine sediment and blue crab

    Science.gov (United States)

    Liebens, J.; Mohrherr, C.J.; Karouna-Renier, N. K.; Snyder, R.A.; Rao, K.R.

    2011-01-01

    The objective of the present study was to evaluate the relationships between the quantity, toxicity, and compositional profile of dioxin/furan compounds (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) in estuarine sediment and in the blue crab (Callinectes sapidus). Sediment and blue crab samples were collected in three small urban estuaries that are in relatively close proximity to each other. Results show that differences between PCDD/F and DL-PCB mass concentrations and total toxic equivalents (TEQ) toxicity in sediments of the three estuaries are reflected in those of the blue crab. TEQs are higher in the hepatopancreas of the crabs than in the sediment, but the concentration factor is inversely proportional to the TEQ in the sediments. Congener profiles in the crabs are systematically different from those in the sediments, and the difference is more pronounced for PCDD/Fs than for DL-PCBs, possibly due to differences in metabolization rates. Compared with sediment profiles, more lesser-chlorinated PCDD/Fs that have higher TEFs accumulate in crab hepatopancreas. This selective bioaccumulation of PCDD/Fs results in a TEQ augmentation in crab hepatopancreas compared with sediments. The bioaccumulation in the blue crab is also selective for PCDD/Fs over DL-PCBs. ?? 2011 Springer Science+Business Media B.V.

  4. Functional trait responses to sediment deposition reduce macrofauna-mediated ecosystem functioning in an estuarine mudflat

    Science.gov (United States)

    Mestdagh, Sebastiaan; Bagaço, Leila; Braeckman, Ulrike; Ysebaert, Tom; De Smet, Bart; Moens, Tom; Van Colen, Carl

    2018-05-01

    Human activities, among which dredging and land use change in river basins, are altering estuarine ecosystems. These activities may result in changes in sedimentary processes, affecting biodiversity of sediment macrofauna. As macrofauna controls sediment chemistry and fluxes of energy and matter between water column and sediment, changes in the structure of macrobenthic communities could affect the functioning of an entire ecosystem. We assessed the impact of sediment deposition on intertidal macrobenthic communities and on rates of an important ecosystem function, i.e. sediment community oxygen consumption (SCOC). An experiment was performed with undisturbed sediment samples from the Scheldt river estuary (SW Netherlands). The samples were subjected to four sedimentation regimes: one control and three with a deposited sediment layer of 1, 2 or 5 cm. Oxygen consumption was measured during incubation at ambient temperature. Luminophores applied at the surface, and a seawater-bromide mixture, served as tracers for bioturbation and bio-irrigation, respectively. After incubation, the macrofauna was extracted, identified, and counted and then classified into functional groups based on motility and sediment reworking capacity. Total macrofaunal densities dropped already under the thinnest deposits. The most affected fauna were surficial and low-motility animals, occurring at high densities in the control. Their mortality resulted in a drop in SCOC, which decreased steadily with increasing deposit thickness, while bio-irrigation and bioturbation activity showed increases in the lower sediment deposition regimes but decreases in the more extreme treatments. The initial increased activity likely counteracted the effects of the drop in low-motility, surficial fauna densities, resulting in a steady rather than sudden fall in oxygen consumption. We conclude that the functional identity in terms of motility and sediment reworking can be crucial in our understanding of the

  5. Functional trait responses to sediment deposition reduce macrofauna-mediated ecosystem functioning in an estuarine mudflat

    Directory of Open Access Journals (Sweden)

    S. Mestdagh

    2018-05-01

    Full Text Available Human activities, among which dredging and land use change in river basins, are altering estuarine ecosystems. These activities may result in changes in sedimentary processes, affecting biodiversity of sediment macrofauna. As macrofauna controls sediment chemistry and fluxes of energy and matter between water column and sediment, changes in the structure of macrobenthic communities could affect the functioning of an entire ecosystem. We assessed the impact of sediment deposition on intertidal macrobenthic communities and on rates of an important ecosystem function, i.e. sediment community oxygen consumption (SCOC. An experiment was performed with undisturbed sediment samples from the Scheldt river estuary (SW Netherlands. The samples were subjected to four sedimentation regimes: one control and three with a deposited sediment layer of 1, 2 or 5 cm. Oxygen consumption was measured during incubation at ambient temperature. Luminophores applied at the surface, and a seawater–bromide mixture, served as tracers for bioturbation and bio-irrigation, respectively. After incubation, the macrofauna was extracted, identified, and counted and then classified into functional groups based on motility and sediment reworking capacity. Total macrofaunal densities dropped already under the thinnest deposits. The most affected fauna were surficial and low-motility animals, occurring at high densities in the control. Their mortality resulted in a drop in SCOC, which decreased steadily with increasing deposit thickness, while bio-irrigation and bioturbation activity showed increases in the lower sediment deposition regimes but decreases in the more extreme treatments. The initial increased activity likely counteracted the effects of the drop in low-motility, surficial fauna densities, resulting in a steady rather than sudden fall in oxygen consumption. We conclude that the functional identity in terms of motility and sediment reworking can be crucial in our

  6. Distribution of rare earth elements in the estuarine and coastal sediments of the Daliao River System, China

    International Nuclear Information System (INIS)

    Chunye Lin; Shaoqing Liu; Mengchang He; Ruiping Li

    2013-01-01

    The Daliao River System (DRS) estuary in Liaodong Bay features a highly industrial, urbanized, and agricultural catchment. The objective of this study was to determine the content, behavior, and distribution of the rare earth elements (REEs) in the estuarine and coastal sediments. To this end, 35 sediment samples were collected from the estuarine and coastal area and analyzed for REEs, Fe, Al, and Mn. The mean concentrations in mg kg -1 of the sediments were 33.4 (La), 64.1 (Ce), 7.9 (Pr), 29.0 (Nd), 5.4 (Sm), 1.2 (Eu), 4.2 (Gd), 0.78 (Tb), 4.0 (Dy), 0.84 (Ho), 2.3 (Er), 0.40 (Tm), 2.3 (Yb), and 0.37 (Lu). The REE concentrations in the sediments were significantly correlated with one another (r 2 = 0.959-0.988) and the concentrations of Fe, Al, and Mn (r 2 = 0.768-0.870). The total concentration ΣREE ranged from 73.5 to 203.5 mg kg -1 , with an average of 156.0 mg kg -1 being observed, and generally higher in the estuarine sediments than in the coastal sediments, most likely due to the salt-induced coagulation of river colloids and subsequently their accumulation at the estuarine bottom. The ratio of light REEs (ΣLREE) to heavy REEs (ΣHREE) was 9.4. Chondrite-normalized REE distributions were observed to be similar for the estuarine and coastal sediments, riverine suspended particles, and watershed soils of the DRS with higher LRRE enrichment than HREE and greater Eu depletion than Ce depletion. These results demonstrate that neither geochemical processes that carry soils to estuarine sediments nor long-term industrial and agricultural activities alter the distribution or fractionation of the REEs in the study area. (author)

  7. Calibration of an estuarine sediment transport model to sediment fluxes as an intermediate step for simulation of geomorphic evolution

    Science.gov (United States)

    Ganju, N.K.; Schoellhamer, D.H.

    2009-01-01

    Modeling geomorphic evolution in estuaries is necessary to model the fate of legacy contaminants in the bed sediment and the effect of climate change, watershed alterations, sea level rise, construction projects, and restoration efforts. Coupled hydrodynamic and sediment transport models used for this purpose typically are calibrated to water level, currents, and/or suspended-sediment concentrations. However, small errors in these tidal-timescale models can accumulate to cause major errors in geomorphic evolution, which may not be obvious. Here we present an intermediate step towards simulating decadal-timescale geomorphic change: calibration to estimated sediment fluxes (mass/time) at two cross-sections within an estuary. Accurate representation of sediment fluxes gives confidence in representation of sediment supply to and from the estuary during those periods. Several years of sediment flux data are available for the landward and seaward boundaries of Suisun Bay, California, the landward-most embayment of San Francisco Bay. Sediment flux observations suggest that episodic freshwater flows export sediment from Suisun Bay, while gravitational circulation during the dry season imports sediment from seaward sources. The Regional Oceanic Modeling System (ROMS), a three-dimensional coupled hydrodynamic/sediment transport model, was adapted for Suisun Bay, for the purposes of hindcasting 19th and 20th century bathymetric change, and simulating geomorphic response to sea level rise and climatic variability in the 21st century. The sediment transport parameters were calibrated using the sediment flux data from 1997 (a relatively wet year) and 2004 (a relatively dry year). The remaining years of data (1998, 2002, 2003) were used for validation. The model represents the inter-annual and annual sediment flux variability, while net sediment import/export is accurately modeled for three of the five years. The use of sediment flux data for calibrating an estuarine geomorphic

  8. Interactions between waves, sediment, and turbulence on a shallow estuarine mudflat

    Science.gov (United States)

    MacVean, Lissa J.; Lacy, Jessica R.

    2014-01-01

    Measurements were collected on a shallow estuarine mudflat in northern San Francisco Bay to examine the physical processes controlling waves, turbulence, sediment resuspension, and their interactions. Tides alone forced weak to moderate currents of 10–30 cm s-1 in depths of 0–3 m, and maintained a background suspension of 30–50 mg L21 of fine sediment. In the presence of wind waves, bottom orbital velocities spanned 20–30 cm s-1, suspended-sediment concentrations (SSC) at 15 and 30 cm above the bed (cmab) increased by 1–2 orders of magnitude, and vertical gradients in SSC were strong enough to produce turbulence-limiting stratification, with gradient Richardson numbers exceeding 0.25. Simultaneously, turbulent

  9. Microbial degradation of petroleum hydrocarbons in estuarine sediment of Tama River in Tokyo urban area

    International Nuclear Information System (INIS)

    Yamane, Akiko; Hosomi, Masaaki; Murakami, Akihiko; Sakakibara, Koji

    1997-01-01

    Aerobic and anaerobic biodegradation rates of petroleum hydrocarbons, i.e., hexadecane (HEX), phenanthrene (PHE), and anthracene (ANT), were determined in estuarine sediment of the Tama River in urban Tokyo, followed by estimating their respective degradation potential. While in a sediment slurry, the aerobic biodegradation rates of these petroleum hydrocarbons ranged from 40 to 70 μg.g -1 dry sediment:day -1 . The anaerobic biodegradation rate of HEX was found to be 5 -8 μg.g -1 dry sediment.day -1 , whereas that of PHE and ANT could not be detected following a 2-month incubation. Aerobic degradation of HEX was not affected by coexistence with either PHE or ANT, nor by the salinity level. The number of HEX-, PHE-, or ANT-utilizing bacteria ranged from 5 - 10% of the total number of aerobic heterotrophic bacteria. We calculated their biodegradation potentials using the biomass of naturally existing petroleum hydrocarbon utilizing bacteria present in the sampled sediment, with results for HEX, PHE, and ANT being 1.0 -3.5, 4.2 x 10 -2 , and 1.2 x 10 -2 -9.4 x 10 -1 μg.g -1 dry sediment day -1 , respectively. In the aerobic tidal sediment of the Tama River, the purification potentials of HEX, PHE, and ANT were assessed to be approximately equal to their accumulation potentials occurring at the normal water level. (Author)

  10. Occurrence of quaternary ammonium compounds (QACs) and their application as a tracer for sewage derived pollution in urban estuarine sediments

    International Nuclear Information System (INIS)

    Li, Xiaolin; Luo, Xiaojun; Mai, Bixian; Liu, Jingqin; Chen, Li; Lin, Shanshan

    2014-01-01

    Particle reactive organic contaminants in estuarine sediments can lead to various environmental problems affecting ecosystem and public health. In this study, the occurrence and homologous distribution pattern of quaternary ammonium compounds (QACs) in the surficial sediments collected from the Pearl River Estuary (PRE), China were examined along with polychlorinated biphenyls (PCBs) and polybrominated diphenylethers (PBDEs). The composition pattern of the QACs was found to be uniform in most of the sediments analyzed throughout the PRE, and the average composition pattern was identical to that determined in the sewage sludge from Guangzhou, the biggest city in the PRE. Dialkyldimethylammonium compounds, the most abundant type of QACs, positively correlated to the total concentrations of PCBs and PBDEs in most of the sediments with similar composition patterns. Therefore, the QACs are proposed as potential tracers to evaluate the transport of sewage-derived pollution in estuarine environments. -- Highlights: • Analysis method is developed for quaternary ammonium compounds (QACs) in sediment. • Occurrence of QACs is observed in the Pearl River Estuary, China for the first time. • QACs are proposed to be a tracer for sewage derived pollution in estuarine sediment. -- QACs were found to be present in the estuarine sediments in China for the first time and proposed as potential tracers for sewage-derived pollution in urban estuary

  11. Surfactant-induced mobilisation of trace metals from estuarine sediment: Implications for contaminant bioaccessibility and remediation

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Anu [School of Earth, Ocean and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA (United Kingdom); Turner, Andrew [School of Earth, Ocean and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA (United Kingdom)], E-mail: aturner@plymouth.ac.uk

    2009-02-15

    The mobilisation of metals (Al, Fe, Cd, Cu, Mn, Ni, Pb, Sn, Zn) from contaminated estuarine sediment has been examined using commercially available surfactants. Metal release by the anionic surfactant, sodium dodecyl sulphate (SDS), increased with increasing amphiphile concentration up to and above its critical micelle concentration (CMC). Metal mobilisation by the bile acid salt, sodium taurocholate, and the nonionic surfactant, Triton X-100, however, did not vary with amphiphile concentration. SDS was the most efficient surfactant in mobilising metals from the sample, and Cd, Cu and Ni were released to the greatest extents (12-18% of total metal at [SDS] > CMC). Metal mobilisation appeared to proceed via complexation with anionic amphiphiles and denudation of hydrophobic host phases. Surfactants may play an important role in the solubilisation of metals in the digestive environment of deposit-feeding animals and, potentially, in the remediation of metal-contaminated soil and sediment. - Significant quantities of metals are mobilised from estuarine sediment by commercially available surfactants.

  12. Impacts of flocculation on the distribution and diagenesis of iron in boreal estuarine sediments

    Directory of Open Access Journals (Sweden)

    T. Jilbert

    2018-03-01

    Full Text Available Iron (Fe plays a key role in sedimentary diagenetic processes in coastal systems, participating in various redox reactions and influencing the burial of organic carbon. Large amounts of Fe enter the marine environment from boreal river catchments associated with dissolved organic matter (DOM and as colloidal Fe oxyhydroxides, principally ferrihydrite. However, the fate of this Fe pool in estuarine sediments has not been extensively studied. Here we show that flocculation processes along a salinity gradient in an estuary of the northern Baltic Sea efficiently transfer Fe and OM from the dissolved phase into particulate material that accumulates in the sediments. Flocculation of Fe and OM is partially decoupled. This is likely due to the presence of discrete colloidal ferrihydrite in the freshwater Fe pool, which responds differently from DOM to estuarine mixing. Further decoupling of Fe from OM occurs during sedimentation. While we observe a clear decline with distance offshore in the proportion of terrestrial material in the sedimentary particulate organic matter (POM pool, the distribution of flocculated Fe in sediments is modulated by focusing effects. Labile Fe phases are most abundant at a deep site in the inner basin of the estuary, consistent with input from flocculation and subsequent focusing. The majority of the labile Fe pool is present as Fe (II, including both acid-volatile sulfur (AVS-bound Fe and unsulfidized phases. The ubiquitous presence of unsulfidized Fe (II throughout the sediment column suggests Fe (II-OM complexes derived from reduction of flocculated Fe (III-OM, while other Fe (II phases are likely derived from the reduction of flocculated ferrihydrite. Depth-integrated rates of Fe (II accumulation (AVS-Fe + unsulfidized Fe (II + pyrite for the period 1970–2015 are greater in the inner basin of the estuary with respect to a site further offshore, confirming higher rates of Fe reduction in near-shore areas

  13. Impacts of flocculation on the distribution and diagenesis of iron in boreal estuarine sediments

    Science.gov (United States)

    Jilbert, Tom; Asmala, Eero; Schröder, Christian; Tiihonen, Rosa; Myllykangas, Jukka-Pekka; Virtasalo, Joonas J.; Kotilainen, Aarno; Peltola, Pasi; Ekholm, Päivi; Hietanen, Susanna

    2018-03-01

    Iron (Fe) plays a key role in sedimentary diagenetic processes in coastal systems, participating in various redox reactions and influencing the burial of organic carbon. Large amounts of Fe enter the marine environment from boreal river catchments associated with dissolved organic matter (DOM) and as colloidal Fe oxyhydroxides, principally ferrihydrite. However, the fate of this Fe pool in estuarine sediments has not been extensively studied. Here we show that flocculation processes along a salinity gradient in an estuary of the northern Baltic Sea efficiently transfer Fe and OM from the dissolved phase into particulate material that accumulates in the sediments. Flocculation of Fe and OM is partially decoupled. This is likely due to the presence of discrete colloidal ferrihydrite in the freshwater Fe pool, which responds differently from DOM to estuarine mixing. Further decoupling of Fe from OM occurs during sedimentation. While we observe a clear decline with distance offshore in the proportion of terrestrial material in the sedimentary particulate organic matter (POM) pool, the distribution of flocculated Fe in sediments is modulated by focusing effects. Labile Fe phases are most abundant at a deep site in the inner basin of the estuary, consistent with input from flocculation and subsequent focusing. The majority of the labile Fe pool is present as Fe (II), including both acid-volatile sulfur (AVS)-bound Fe and unsulfidized phases. The ubiquitous presence of unsulfidized Fe (II) throughout the sediment column suggests Fe (II)-OM complexes derived from reduction of flocculated Fe (III)-OM, while other Fe (II) phases are likely derived from the reduction of flocculated ferrihydrite. Depth-integrated rates of Fe (II) accumulation (AVS-Fe + unsulfidized Fe (II) + pyrite) for the period 1970-2015 are greater in the inner basin of the estuary with respect to a site further offshore, confirming higher rates of Fe reduction in near-shore areas. Mössbauer 57Fe

  14. Chemistry and behaviour of B, Ca and Mg in interstitial waters of sediments from the coastal and estuarine regions of Mandovi river along the west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Shirodkar, P.V.; SenGupta, R.

    Interstitial waters of coastal and estuarine sediments show enrichment of B and Ca and a decrease in Mg. Increase in interstitial B in sediments is due to the downward diffusion from overlying water and release from solid phases by physicochemical...

  15. The capability of estuarine sediments to remove nitrogen: implications for drinking water resource in Yangtze Estuary.

    Science.gov (United States)

    Liu, Lin; Wang, Dongqi; Deng, Huanguang; Li, Yangjie; Chang, Siqi; Wu, Zhanlei; Yu, Lin; Hu, Yujie; Yu, Zhongjie; Chen, Zhenlou

    2014-09-01

    Water in the Yangtze Estuary is fresh most of the year because of the large discharge of Yangtze River. The Qingcaosha Reservoir built on the Changxing Island in the Yangtze Estuary is an estuarine reservoir for drinking water. Denitrification rate in the top 10 cm sediment of the intertidal marshes and bare mudflat of Yangtze Estuarine islands was measured by the acetylene inhibition method. Annual denitrification rate in the top 10 cm of sediment was 23.1 μmol m(-2) h(-1) in marshes (ranged from 7.5 to 42.1 μmol m(-2) h(-1)) and 15.1 μmol m(-2) h(-1) at the mudflat (ranged from 6.6 to 26.5 μmol m(-2) h(-1)). Annual average denitrification rate is higher at mashes than at mudflat, but without a significant difference (p = 0.084, paired t test.). Taking into account the vegetation and water area of the reservoir, a total 1.42 × 10(8) g N could be converted into nitrogen gas (N2) annually by the sediment, which is 97.7 % of the dissolved inorganic nitrogen input through precipitation. Denitrification in reservoir sediment can control the bioavailable nitrogen level of the water body. At the Yangtze estuary, denitrification primarily took place in the top 4 cm of sediment, and there was no significant spatial or temporal variation of denitrification during the year at the marshes and mudflat, which led to no single factor determining the denitrification process but the combined effects of the environmental factors, hydrologic condition, and wetland vegetation.

  16. Organic Matter Loading Modifies the Microbial Community Responsible for Nitrogen Loss in Estuarine Sediments.

    Science.gov (United States)

    Babbin, Andrew R; Jayakumar, Amal; Ward, Bess B

    2016-04-01

    Coastal marine sediments, as locations of substantial fixed nitrogen loss, are very important to the nitrogen budget and to the primary productivity of the oceans. Coastal sediment systems are also highly dynamic and subject to periodic natural and anthropogenic organic substrate additions. The response to organic matter by the microbial community involved in nitrogen loss processes was evaluated using mesocosms of Chesapeake Bay sediments. Over the course of a 50-day incubation, rates of anammox and denitrification were measured weekly using (15)N tracer incubations, and samples were collected for genetic analysis. Rates of both nitrogen loss processes and gene abundances associated with them corresponded loosely, probably because heterogeneities in sediments obscured a clear relationship. The rates of denitrification were stimulated more, and the fraction of nitrogen loss attributed to anammox slightly reduced, by the higher organic matter addition. Furthermore, the large organic matter pulse drove a significant and rapid shift in the denitrifier community composition as determined using a nirS microarray, indicating that the diversity of these organisms plays an essential role in responding to anthropogenic inputs. We also suggest that the proportion of nitrogen loss due to anammox in these coastal estuarine sediments may be underestimated due to temporal dynamics as well as from methodological artifacts related to conventional sediment slurry incubation approaches.

  17. Disturbances to metal partitioning during toxicity testing of iron(II)-rich estuarine pore waters and whole sediments.

    Science.gov (United States)

    Simpson, Stuart L; Batley, Graeme E

    2003-02-01

    Metal partitioning is altered when suboxic estuarine sediments containing Fe(II)-rich pore waters are disturbed during collection, preparation, and toxicity testing. Experiments with model Fe(II)-rich pore waters demonstrated the rates at which adsorptive losses of Cd, Cu, Ni, Mn, Pb, and Zn occur upon exposure to air. Experiments with Zn-contaminated estuarine sediments demonstrated large and often unpredictable changes to metal partitioning during sediment storage, removal of organisms, and homogenization before testing. Small modifications to conditions, such as aeration of overlying waters, caused large changes to the metal partitioning. Disturbances caused by sediment collection required many weeks for reestablishment of equilibrium. Bioturbation by benthic organisms led to oxidation of pore-water Fe(II) and lower Zn fluxes because of the formation of Fe hydroxide precipitates that adsorb pore-water Zn. For five weeks after the addition of organisms to sediments, Zn fluxes increased slowly as the organisms established themselves in the sediments, indicating that the establishment of equilibrium was not rapid. The results are discussed in terms of the dynamic nature of suboxic, Fe(II)-rich estuarine sediments, how organisms perturb their environment, and the importance of understanding chemistry in toxicity testing with whole sediments or pore water. Recommendations are provided for the handling of sediments for toxicity testing.

  18. Paleoclimatic and paleoceanographic studies of estuarine and marine sediments using strontium isotopes

    International Nuclear Information System (INIS)

    Ingram, B.L.

    1992-01-01

    Strontium isotopic ratio ( 87 Sr/ 86 Sr) measurements in fossil carbonates and phosphates are used to evaluate paleoceanographic and paleoclimatic environments in Quaternary, Pliocene-Pleistocene, and mid-Cretaceous estuarine and marine sediments. The use of 87 Sr/ 86 Sr measurements as an estuarine paleosalinity and paleoclimatic indicator is developed and applied to San Francisco Bay. 87 Sr/ 86 Sr measurements of foraminifer and molluscan fossils contained in estuarine sediments of late Pleistocene (ca 115 to 125 ka) and late Holocene (4.5 ka) age show cyclic variations indicating that salinity fluctuated with periods of several hundred years, probably reflecting wet-dry cycles associated with fluctuations in solar irradiance caused by sunspot cycles. The average salinity in San Pablo and Richardson bays was significantly lower (by 6 to 8%) over much of the past 4.5 ka than at present, reflecting a combination of decreased freshwater inflow at present associated with water diversion and wetter climatic conditions prior to 2000 years ago. Salinity data are converted to river discharge using salinity-delta flow relations derived from historical records for San Francisco Bay. The data indicate that annual freshwater inflow was at least twice the modern pre-diversion average between 2.5 and 3.0 Ka; this time period is also identified as one of wetter climatic conditions by lake level and treeline records from the Sierra Nevada. Strontium isotopic measurements of marine carbonate and fish teeth to middle Cretaceous age are used to increase the resolution of the existing seawater Sr isotope versus time curve and to assess models for global oceanic anoxic events. The new data using fish teeth show less scatter and variability than previous data. Negative excursions in the 87 Sr/ 86 Sr ratio of 7-14 parts in 10 -5 during Aptian anoxic events suggest a link between increased submarine volcanism and oceanic anoxia

  19. Implications of tidally-varying bed stress and intermittent estuarine stratification on fine-sediment dynamics through the Mekong's tidal river to estuarine reach

    Science.gov (United States)

    McLachlan, R. L.; Ogston, A. S.; Allison, M. A.

    2017-09-01

    River gauging stations are often located upriver of tidal propagation where sediment transport processes and storage are impacted by widely varying ratios of marine to freshwater influence. These impacts are not yet thoroughly understood. Therefore, sediment fluxes measured at these stations may not be suitable for predicting changes to coastal morphology. To characterize sediment transport dynamics in this understudied zone, flow velocity, salinity, and suspended-sediment properties (concentration, size, and settling velocity) were measured within the tidal Sông Hậu distributary of the lower Mekong River, Vietnam. Fine-sediment aggregation, settling, and trapping rates were promoted by seasonal and tidal fluctuations in near-bed shear stress as well as the intermittent presence of a salt wedge and estuary turbidity maximum. Beginning in the tidal river, fine-grained particles were aggregated in freshwater. Then, in the interface zone between the tidal river and estuary, impeded near-bed shear stress and particle flux convergence promoted settling and trapping. Finally, in the estuary, sediment retention was further encouraged by stratification and estuarine circulation which protected the bed against particle resuspension and enhanced particle aggregation. These patterns promote mud export ( 1.7 t s-1) from the entire study area in the high-discharge season when fluvial processes dominate and mud import ( 0.25 t s-1) into the estuary and interface zone in the low-discharge season when estuarine processes dominate. Within the lower region of the distributaries, morphological change in the form of channel abandonment was found to be promoted within minor distributaries by feedbacks between channel depth, vertical mixing, and aggregate trapping. In effect, this field study sheds light on the sediment trapping capabilities of the tidal river - estuary interface zone, a relatively understudied region upstream of where traditional concepts place sites of deposition

  20. The fate of technetium in reduced estuarine sediments: Combining direct and indirect analyses

    Energy Technology Data Exchange (ETDEWEB)

    Burke, Ian T. [Earth Surface Science Institute, School of Earth and Environment, University of Leeds, Leeds LS2 9JT (United Kingdom); Livens, Francis R. [Centre for Radiochemistry Research, School of Earth, Atmospheric and Environmental Sciences, University of Manchester, Manchester M13 9PL (United Kingdom); Lloyd, Jonathan R. [Williamson Centre for Molecular Environmental Science, School of Earth, Atmospheric and Environmental Sciences, University of Manchester, Manchester M13 9PL (United Kingdom); Brown, Andrew P. [School of Process, Environmental and Materials Engineering, University of Leeds, Leeds LS2 9JT (United Kingdom); Law, Gareth T.W. [Earth Surface Science Institute, School of Earth and Environment, University of Leeds, Leeds LS2 9JT (United Kingdom); McBeth, Joyce M. [Williamson Centre for Molecular Environmental Science, School of Earth, Atmospheric and Environmental Sciences, University of Manchester, Manchester M13 9PL (United Kingdom); Ellis, Beverley L.; Lawson, Richard S. [Department of Nuclear Medicine, Manchester Royal Infirmary, Manchester M13 9WL (United Kingdom); Morris, Katherine, E-mail: k.morris@see.leeds.ac.uk [Earth Surface Science Institute, School of Earth and Environment, University of Leeds, Leeds LS2 9JT (United Kingdom)] [Williamson Centre for Molecular Environmental Science, School of Earth, Atmospheric and Environmental Sciences, University of Manchester, Manchester M13 9PL (United Kingdom)

    2010-02-15

    Technetium-99 is an important fission product in radioactive wastes. As Tc(VII)O{sub 4}{sup -}, Tc is highly mobile in oxic environments but, under reducing conditions, Tc becomes strongly associated with sediments as hydrous Tc(IV)O{sub 2} like phases. In order to further examine the behaviour of Tc over a range of concentrations in estuarine sediments, anoxic incubation experiments were combined with a range of direct (transmission electron microscopy and gamma camera imaging) and indirect (incubation experiments and chemical extractions) experimental techniques. When TcO{sub 4}{sup -} was incubated in sediment microcosms at micro-molar (10{sup -6} mol L{sup -1}) concentrations, >99% TcO{sub 4}{sup -} was removed from solution over the course of 36 days in systems undergoing active microbial Fe(III)-reduction. By contrast, when spiked into pre-reduced estuarine sediments that were predominantly Fe(III)-reducing (incubated for 60 days) or SO{sub 4}{sup 2-}reducing (incubated for 270 days), >99% TcO{sub 4}{sup -} was removed from solution in under 10 min in both microbially active and heat sterilised systems. Chemical extraction techniques showed that 70 {+-} 3% of Tc bound to sediments was remobilised when sediments were exposed to the first strong oxidant (H{sub 2}O{sub 2}) in the extraction scheme. At higher Tc concentrations ({approx}0.05 mol kg{sup -1} of sediment) scanning transmission electron microscopy, combined with energy dispersive X-ray mapping, was used to examine the associations of Tc in sediments. At these concentrations, Tc was localised and co-associated with nanometre size Fe(II)-rich particles, consistent with the hypothesis that removal of Tc may be controlled by reduction of Tc(VII) to Tc(IV) by biogenic Fe(II) in sediments. In addition, gamma camera imaging with the {gamma}-emitting {sup 99m}TcO{sub 4}{sup -} (half-life 6 h) at pico-molar (10{sup -12} mol L{sup -1}) concentrations, was used to visualise the interaction of Tc in sediments at

  1. Inorganic As speciation and bioavailability in estuarine sediments of Todos os Santos Bay, BA, Brazil

    International Nuclear Information System (INIS)

    Hatje, V.; Macedo, S.M.; Jesus, R.M. de; Cotrim, G.; Garcia, K.S.; Queiroz, A.F. de; Ferreira, S.L.C.

    2010-01-01

    Research highlights: → Total concentration of As at several stations along Todos os Santos Bay, was above TEL value. → At Subae and Paraguacu systems, As (V) was the dominant species, which is less toxic and less mobile than As (III). → Arsenic concentrations at Jaguaripe estuary were higher than in other estuaries and As (III) was the dominant species. → Relationship between As, Fe, Mn and sand indicated that As enrichment at Jaguaripe River is natural. → As concentrations in sediments and biota suggest that As is bioavailable and it is accumulating in marine organisms, which may impose human risks. → Slurry sampling showed to be a easy, accurate procedure to be used for As determination in estuarine samples. - Abstract: The spatial distribution of As (total As, As (III) and As (V)) in estuarine sediments from the main tributaries of Todos os Santos Bay, BA, Brazil, was evaluated under high and low flow conditions. The concentrations of As were determined using a slurry sampling procedure with hydride generation atomic absorption spectrometry (HG-AAS). The highest concentrations were observed at estuary mouths, and exceeded conservative lower threshold value (Threshold Effects Level; TEL). Due to the oxic conditions and abundance of Mn and Fe (oxyhydr)oxides in the sediments, most inorganic arsenic in the Subae and Paraguacu estuaries was present as As (V). Nevertheless, the concentration of As (III) at several locations along the Jaguaripe River were also above the TEL value, suggesting that As may be toxic to biota. In the Subae estuary, antropogenic activities are the main source of As. At the Jaguaripe and at Paraguacu estuaries, nevertheless, natural sources of As need to be considered to explain the distribution patterns.

  2. Santos estuarine sediments, Brazil - metal and trace element assessment by neutron activation analysis

    International Nuclear Information System (INIS)

    Amorim, Eduardo P.; Favaro, Deborah I.T.; Berbel, Glaucia; Braga, Elisabete S.

    2009-01-01

    The Santos estuary system is an intricate pattern of tidal channels and small rivers originating from the adjacent Pre-Cambrian slopes. These two major estuaries share a common area in the upper portion of the region which interacts with each other. The largest harbor in Latin America is located at the eastern outlet of the Santos estuary. This intricate and sensitive ecosystem is highly susceptible to human impact from industrial activities, urban sewage and polluted solid wastes disposal. Due to its high vulnerability CETESB (Environmental Control Agency of the Sao Paulo State) sporadically monitors the contamination levels of water, sediment and marine organisms in this region. The present study reports results concerning the distribution of some major, trace and rare earth elements in the Santos estuarine marine sediments. Thirty two bottom sediment samples (SS0601 to SS0616 (summer) and SW0601 to SW0616 (winter) were collected in this estuary, including regions of Sao Vicente, Santos, Cubatao and Vicente de Carvalho, by a vanVeen sampler in the summer and winter of 2006. Multielemental analysis was carried out by instrumental neutron activation analysis (INAA). The concentration values obtained for As and metals Cr and Zn in the sediment samples were compared to Canadian Council of Minister of the Environment (CCME) oriented values (TEL and PEL values) and are adopted by CETESB. (author)

  3. Santos estuarine sediments, Brazil - metal and trace element assessment by neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Amorim, Eduardo P.; Favaro, Deborah I.T., E-mail: ducamorim@yahoo.com.b, E-mail: defavaro@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP) Sao Paulo, SP (Brazil); Berbel, Glaucia; Braga, Elisabete S., E-mail: edsbraga@usp.b [Universidade de Sao Paulo (USP), SP (Brazil). Inst. Oceanografico. Lab. de Nutrientes, Micronutrientes e Tracos nos Oceanos (LABNUT)

    2009-07-01

    The Santos estuary system is an intricate pattern of tidal channels and small rivers originating from the adjacent Pre-Cambrian slopes. These two major estuaries share a common area in the upper portion of the region which interacts with each other. The largest harbor in Latin America is located at the eastern outlet of the Santos estuary. This intricate and sensitive ecosystem is highly susceptible to human impact from industrial activities, urban sewage and polluted solid wastes disposal. Due to its high vulnerability CETESB (Environmental Control Agency of the Sao Paulo State) sporadically monitors the contamination levels of water, sediment and marine organisms in this region. The present study reports results concerning the distribution of some major, trace and rare earth elements in the Santos estuarine marine sediments. Thirty two bottom sediment samples (SS0601 to SS0616 (summer) and SW0601 to SW0616 (winter) were collected in this estuary, including regions of Sao Vicente, Santos, Cubatao and Vicente de Carvalho, by a vanVeen sampler in the summer and winter of 2006. Multielemental analysis was carried out by instrumental neutron activation analysis (INAA). The concentration values obtained for As and metals Cr and Zn in the sediment samples were compared to Canadian Council of Minister of the Environment (CCME) oriented values (TEL and PEL values) and are adopted by CETESB. (author)

  4. Preparation of an estuarine sediment quality control material for the determination of trace metals

    Directory of Open Access Journals (Sweden)

    Hatje Vanessa

    2006-01-01

    Full Text Available Quality Control Materials (QCM have being used routinely in daily laboratory work as a tool to fill the gap between need and availability of Certified Reference Materials (CRM. The QCM are a low-cost alternative to CRMs, and they are in high demand, especially, for the implementation of quality control systems in laboratories of several areas. This paper describes the preparation of a QCM for the determination of trace metals in estuarine sediments and the results of an interlaboratory exercise. Homogeneity and stability studies were performed and analysis of variance was carried out with the results. No statistical significant differences were observed in the concentrations of Co, Cr, Cu, Mn, Pb and Zn between- or within bottle results. Neither the storage nor temperature affected the results. Therefore, the QCM produced is considered homogeneous and stable and can be used for statistical control charts, evaluation of reproducibility and interlaboratory exercises.

  5. Rapid and efficient method to extract metagenomic DNA from estuarine sediments.

    Science.gov (United States)

    Shamim, Kashif; Sharma, Jaya; Dubey, Santosh Kumar

    2017-07-01

    Metagenomic DNA from sediments of selective estuaries of Goa, India was extracted using a simple, fast, efficient and environment friendly method. The recovery of pure metagenomic DNA from our method was significantly high as compared to other well-known methods since the concentration of recovered metagenomic DNA ranged from 1185.1 to 4579.7 µg/g of sediment. The purity of metagenomic DNA was also considerably high as the ratio of absorbance at 260 and 280 nm ranged from 1.88 to 1.94. Therefore, the recovered metagenomic DNA was directly used to perform various molecular biology experiments viz. restriction digestion, PCR amplification, cloning and metagenomic library construction. This clearly proved that our protocol for metagenomic DNA extraction using silica gel efficiently removed the contaminants and prevented shearing of the metagenomic DNA. Thus, this modified method can be used to recover pure metagenomic DNA from various estuarine sediments in a rapid, efficient and eco-friendly manner.

  6. The Abundance and Activity of Nitrate-Reducing Microbial Populations in Estuarine Sediments

    Science.gov (United States)

    Cardarelli, E.; Francis, C. A.

    2014-12-01

    Estuaries are productive ecosystems that ameliorate nutrient and metal contaminants from surficial water supplies. At the intersection of terrestrial and aquatic environments, estuarine sediments host major microbially-mediated geochemical transformations. These include denitrification (the conversion of nitrate to nitrous oxide and/or dinitrogen) and dissimilatory nitrate reduction to ammonium (DNRA). Denitrification has historically been seen as the predominant nitrate attenuation process and functions as an effective sink for nitrate. DNRA has previously been believed to be a minor nitrate reduction process and transforms nitrate within the ecosystem to ammonium, a more biologically available N species. Recent studies have compared the two processes in coastal environments and determined fluctuating environmental conditions may suppress denitrification, supporting an increased role for DNRA in the N cycle. Nitrate availability and salinity are factors thought to influence the membership of the microbial communities present, and the nitrate reduction process that predominates. The aim of this study is to investigate how nitrate concentration and salinity alter the transcript abundances of N cycling functional gene markers for denitrification (nirK, nirS) and DNRA (nrfA) in estuarine sediments at the mouth of the hypernutrified Old Salinas River, CA. Short-term whole core incubations amended with artificial freshwater/artificial seawater (2 psu, 35 psu) and with varying NO3- concentrations (200mM, 2000mM) were conducted to assess the activity as well as the abundance of the nitrate-reducing microbial populations present. Gene expression of nirK, nirS, and nrfA at the conclusion of the incubations was quantified using reverse transcription quantitative polymerase chain reaction (RT-qPCR). High abundances of nirK, nirS, and nrfA under particular conditions coupled with the resulting geochemical data ultimately provides insight onto how the aforementioned factors

  7. Impact of silver nanoparticles on benthic prokaryotes in heavy metal-contaminated estuarine sediments in a tropical environment.

    Science.gov (United States)

    Antizar-Ladislao, B; Bhattacharya, B D; Ray Chaudhuri, S; Sarkar, S K

    2015-10-15

    Little knowledge is available about the potential impact of commercial silver nanoparticles (Ag-NPs) on estuarine microbial communities. The Hugli river estuary, India, is susceptible to heavy metals pollution through boat traffic, and there is the potential for Ag-NP exposure via effluent discharged from ongoing municipal and industrial activities located in close proximity. This study investigated the effects of commercial Ag-NPs on native microbial communities in estuarine sediments collected from five stations, using terminal restriction fragment length polymorphism (T-RFLP) technique. An increase in the number of bacteria in consortium in sediments was observed following exposure to Ag-NPs. In general microbial communities may be resistant in estuarine systems to the antimicrobial effects of commercial Ag-NPs, but key microorganisms, such as Pelobacter propionicus, disappeared following exposure to Ag-NPs. In conclusion, the T-RFLP analysis indicated that Ag-NPs have the potential to shape estuarine sediment bacterial community structure. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Integrated quality assessment of sediments from harbour areas in Santos-São Vicente Estuarine System, Southern Brazil

    Science.gov (United States)

    Buruaem, Lucas Moreira; de Castro, Ítalo Braga; Hortellani, Marcos Antonio; Taniguchi, Satie; Fillmann, Gilberto; Sasaki, Silvio Tarou; Varella Petti, Mônica Angélica; Sarkis, Jorge Eduardo de Souza; Bícego, Márcia Caruso; Maranho, Luciane Alves; Davanso, Marcela Bergo; Nonato, Edmundo Ferraz; Cesar, Augusto; Costa-Lotufo, Leticia Veras; Abessa, Denis Moledo de Souza

    2013-09-01

    Santos-São Vicente Estuarine System is a highly populated coastal zone in Brazil and where it is located the major port of Latin America. Historically, port activities, industrial and domestic effluents discharges have constituted the main sources of contaminants to estuarine system. This study aimed to assess the recent status of sediment quality from 5 zones of Port of Santos by applying a lines-of-evidence approach through integrating results of: (1) acute toxicity of whole sediment and chronic toxicity of liquid phases; (2) grain size, organic matter, organic carbon, nitrogen, phosphorus, trace metals, polycyclic aromatic hydrocarbons, linear alkylbenzenes and butyltins; (3) benthic community descriptors. Results revealed a gradient of increasing contamination for metals and organic compounds, alongside with their geochemical carriers. Sediment liquid phases were more toxic compared to whole sediment. Low number of species and individuals indicated the impoverishment of benthic community. The use of site-specific sediment quality guidelines was more appropriate to predict sediment toxicity. The integration of results through Sediment Quality Triad approach and principal component analysis allowed observing the effects of natural stressors and dredging on sediment quality and benthic distribution. Even with recent governmental efforts to control, pollution is still relevant in Port of Santos and a threat to local ecosystems.

  9. Application of Radiotracer Methodology for Understanding the Influence of Geochemical Fractionation on Metal Bioavailability in Estuarine Sediments

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, N. S.; Baumann, Z. [School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY (United States)

    2013-07-15

    To evaluate the extent to which contaminated sediments could introduce metals into marine food chains, gamma emitting radioisotopes of arsenic, cadmium and chromium were used to study their geochemical fractionation in estuarine sediments and bioavailability to deposit feeding polychaetes. Radioisotopes were added to sediments directly or via planktonic debris and were then fractionated with a sequential extraction scheme after aging for up to 90 days. The assimilation of ingested metals was positively related to their partitioning in the two most readily extractable (labile) sediment fractions and negatively related to refractory organic fractions, oxides, and pyrite. In comparison to uptake from ingested sediment, metal uptake from pore water was negligible. A metal bioaccumulation model, modified to consider their geochemical fractionation, was found to quantitatively predict metal concentrations in benthic polychaetes better than total metal concentrations in sediment. Metals need to desorb from ingested particles into gut fluid within the polychaete gut before they can be assimilated. (author)

  10. Phylogenetic diversity of archaeal 16S rRNA and ammonia monooxygenase genes from tropical estuarine sediments on the central west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Singh, S.K.; Verma, P.; Ramaiah, N.; Anil, A.C.; Shouche, Y.S.

    of Euryarchaeota. Our results indicate that archaeal diversity in tropical estuarine sediments is influenced by the mangrove vegetation bordering the lower stretches of both estuaries. Higher diversity may be related to elevated land drainage during the monsoon...

  11. Weathering rates of oil components in a bioremediation experiment in estuarine sediments

    International Nuclear Information System (INIS)

    Oudot, J.; Merlin, F.X.; Pinvidic, P.

    1998-01-01

    The influence of the addition of a slow release fertiliser on the biodegradation rate of crude oil in experimental plots set up in the mid-tide sediments of an estuarine environment in the bay of Brest, France, was studied during a 9 month experiment. The weathering of total oil and fractions was monitored to the internal conservative biomarker 17 α(H), 21β(H)-30-norhopane by computerised capillary gas-chromatography. At the end of the experiment, the biodegradation rates for total oil, aliphatics, cycloalkanes and aromatics were respectively 40 ± 7, 83 ± 6, 49 ± 10 and 55 ± 18%. The resins and asphaltenes were not degraded. No significant difference in biodegradation rates was observed between fertilised and non-fertilised plots, which was attributed to the high background level of N and P in the site under study. It is thought that if background level of N in the interstitial pore water of the sediment is ≥ 100 μmoles litre -1 then bioremediation through fertilisation may be of limited use only. (author)

  12. Natural attenuation and biosurfactant-stimulated bioremediation of estuarine sediments contaminated with diesel oil.

    Science.gov (United States)

    Bayer, Débora M; Chagas-Spinelli, Alessandra C O; Gavazza, Sávia; Florencio, Lourdinha; Kato, Mario T

    2013-09-01

    We evaluated the bioremediation, by natural attenuation (NA) and by natural attenuation stimulated (SNA) using a rhamnolipid biosurfactant, of estuarine sediments contaminated with diesel oil. Sediment samples (30 cm) were put into 35 cm glass columns, and the concentrations of the 16 polycyclic aromatic hydrocarbons (PAHs) prioritized by the US Environmental Protection Agency were monitored for 111 days. Naphthalene percolated through the columns more than the other PAHs, and, in general, the concentrations of the lower molecular weight PAHs, consisting of two and three aromatic rings, changed during the first 45 days of treatment, whereas the concentrations of the higher molecular weight PAHs, consisting of four, five, and six rings, were more stable. The higher molecular weight PAHs became more available after 45 days, in the deeper parts of the columns (20-30 cm). Evidence of degradation was observed only for some compounds, such as pyrene, with a total removal efficiency of 82 and 78 % in the NA and SNA treatments, respectively, but without significant difference. In the case of total PAH removal, the efficiencies were significantly different of 82 and 67 %, respectively.

  13. Interactions and feedbacks among phytobenthos, hydrodynamics, nutrient cycling and sediment transport in estuarine ecosystems

    Science.gov (United States)

    Bergamasco, A.; De Nat, L.; Flindt, M. R.; Amos, C. L.

    2003-11-01

    Phytobenthic communities can play an active role in modifying the environmental characteristics of the ecosystem in which they live so mediating the human impact on Coastal Zone habitats. Complicated feedbacks couple the establishment of phytobenthic communities with water quality and physical parameters in estuaries. Direct and indirect interactions between physical and biological attributes need to be considered in order to improve the management of these ecosystems to guarantee a sustainable use of coastal resources. Within the project F-ECTS ("Feedbacks of Estuarine Circulation and Transport of Sediments on phytobenthos") this issue was approached through a three-step strategy: (i) Monitoring: detailed fieldwork activities focusing on the measurement and evaluation of the main processes involving hydrodynamics, sediments, nutrients, light and phytobenthic biomass; (ii) Modeling: joint modeling of the suspended particulate matter erosion/transport/deposition and biological mediation of the hydrodynamics and (iii) GIS: development of GIS-based practical tools able to manage and exploit measured and modeled data on the basis of scientific investigation guidelines and procedures. The overall strategy is described by illustrating results of field measurements, providing details of model implementation and demonstrating the GIS-based tools.

  14. Seagrass sediments reveal the long-term deterioration of an estuarine ecosystem

    KAUST Repository

    Serrano, Oscar

    2016-01-28

    © 2016 John Wiley & Sons Ltd. The study of a Posidonia australis sediment archive has provided a record of ecosystem dynamics and processes over the last 600 years in Oyster Harbour (SW Australia). Ecosystem shifts are a widespread phenomenon in coastal areas, and this study identifies baseline conditions and the time-course of ecological change (cycles, trends, resilience and thresholds of ecosystem change) under environmental stress in seagrass-dominated ecosystem. The shifts in the concentrations of chemical elements, carbonates, sediments <0.125 mm and stable carbon isotope signatures (δ13C) of the organic matter were detected between 1850s and 1920s, whereas the shift detected in P concentration occurred several decades later (1960s). The first degradation phase (1850s-1950s) follows the onset of European settlement in Australia and was characterized by a strong increase in sediment accumulation rates and fine-grained particles, driven primarily by enhanced run-off due to land clearance and agriculture in the catchment. About 80% of total seagrass area at Oyster Harbour was lost during the second phase of environmental degradation (1960s until present). The sharp increase in P concentration and the increasing contribution of algae and terrestrial inputs into the sedimentary organic matter pool around 1960s provides compelling evidence of the documented eutrophication of the estuary and the subsequent loss of seagrass meadows. The results presented demonstrate the power of seagrass sedimentary archives to reconstruct the trajectories of anthropogenic pressures on estuarine ecosystem and the associated regime shifts, which can be used to improve the capacity of scientists and environmental managers to understand, predict and better manage ecological change in these ecosystems.

  15. Seagrass sediments reveal the long-term deterioration of an estuarine ecosystem

    KAUST Repository

    Serrano, Oscar; Lavery, Paul; Masque, Pere; Inostroza, Karina; Bongiovanni, James; Duarte, Carlos M.

    2016-01-01

    © 2016 John Wiley & Sons Ltd. The study of a Posidonia australis sediment archive has provided a record of ecosystem dynamics and processes over the last 600 years in Oyster Harbour (SW Australia). Ecosystem shifts are a widespread phenomenon in coastal areas, and this study identifies baseline conditions and the time-course of ecological change (cycles, trends, resilience and thresholds of ecosystem change) under environmental stress in seagrass-dominated ecosystem. The shifts in the concentrations of chemical elements, carbonates, sediments <0.125 mm and stable carbon isotope signatures (δ13C) of the organic matter were detected between 1850s and 1920s, whereas the shift detected in P concentration occurred several decades later (1960s). The first degradation phase (1850s-1950s) follows the onset of European settlement in Australia and was characterized by a strong increase in sediment accumulation rates and fine-grained particles, driven primarily by enhanced run-off due to land clearance and agriculture in the catchment. About 80% of total seagrass area at Oyster Harbour was lost during the second phase of environmental degradation (1960s until present). The sharp increase in P concentration and the increasing contribution of algae and terrestrial inputs into the sedimentary organic matter pool around 1960s provides compelling evidence of the documented eutrophication of the estuary and the subsequent loss of seagrass meadows. The results presented demonstrate the power of seagrass sedimentary archives to reconstruct the trajectories of anthropogenic pressures on estuarine ecosystem and the associated regime shifts, which can be used to improve the capacity of scientists and environmental managers to understand, predict and better manage ecological change in these ecosystems.

  16. Distribution of Fe in waters and bottom sediments of a small estuarine catchment, Pumicestone Region, southeast Queensland, Australia

    International Nuclear Information System (INIS)

    Liaghati, Tania; Cox, Malcolm E.; Preda, Micaela

    2005-01-01

    Dissolved and extractable iron concentrations in surface water, groundwater and bottom sediments were determined for Halls Creek, a small subtropical tidally influenced creek. Dissolved iron concentrations were much higher in fresh surface waters and groundwater compared to the estuarine water. In bottom sediments, iron minerals were determined by X-ray diffraction (XRD); of these, hematite (up to 11%) has formed by precipitation from iron-rich water in the freshwater section of the catchment. Pyrite was only identified in the estuarine reach and demonstrated several morphologies [identified by scanning electron microscopy (SEM)] including loosely and closely packed framboids, and the euhedral form. The forms of pyrite found in bottom sediments indicate in situ production and recrystallisation. In surface waters, pyrite was detected in suspended sediment; due to oxygen concentrations well above 50 μmol/l, it was concluded that framboids do not form in the water column, but are within resuspended bottom sediments or eroded from creek banks. The persistence of framboids in suspended sediments, where oxygen levels are relatively high, could be due to their silica and clay-rich coatings, which prevent a rapid oxidation of the pyrite. In addition to identifying processes of formation and transport of pyrite, this study has environmental significance, as this mineral is a potential source of bioavailable forms of iron, which can be a major nutrient supporting algal growth

  17. Clay mineralogy indicates the muddy sediment provenance in the estuarine-inner shelf of the East China Sea

    Science.gov (United States)

    Zhao, Yifei; Zou, Xinqing; Liu, Qing; Wang, Chenglong; Ge, Chendong; Xu, Min

    2018-02-01

    The estuarine-inner shelf mud regions of the East China Sea (ECS) are valuable for studying the source-to-sink processes of fluvial sediments deposited since the Holocene. In this study, we present evidence of the provenance and environmental evolution of two cores (S5-2 and JC07) from the estuarine-inner shelf regions of the ECS over the past 100 years based on 210Pb dating, high-resolution grain size measurements and clay mineral analyses. The results indicate that the clay mineral assemblages of cores S5-2 and JC07 are dominated by illite, followed by kaolinite and chlorite, and present scarce amounts of smectite. A comparison of these clay mineral assemblages with several major sources reveals that the fine sediments on the estuarine-inner shelf of the ECS represent a mixture of provenances associated with the Yangtze and Yellow Rivers, as well as smaller rivers. However, the contribution of each provenance has varied greatly over the past hundred years, as indicated by the down-core variability due to strong sediment reworking and transport on the inner shelf and the reduction of the sediment load from the Yangtze River basin. In the mud region of the Yangtze River estuary, the sediment from 1930 to 1956 was primarily derived from the Yangtze River, although the Yellow River was also an important influence. From 1956 to 2013, the Yellow River contribution decreased, whereas the Yangtze River contribution correspondingly increased. In the Zhe-Min mud region, the Yangtze River contributed more sediment than did other rivers from 1910 to 1950; however, the Yangtze River contribution gradually decreased from 1950 to 2013. Moreover, the other small rivers accounted for minor contributions, and the East Asian winter monsoon (EAWM) played an important role in the sediment transport process in the ECS. Our results indicate that the weakening/strengthening of the EAWM and a decrease in the sediment load of the Yangtze River influenced the transport and fate of sediment

  18. Vertical distribution of elements in non-polluted estuarine sediments determined by neutron induced prompt gamma-ray and instrumental neutron activation analyses

    International Nuclear Information System (INIS)

    Kuno, A.; Sampei, K.; Matsuo, M.; Sawahata, H.

    1999-01-01

    Neutron induced prompt gamma-ray analysis (PGA) and instrumental neutron activation analysis (INAA) have been applied to the sediments collected from the Yasaka River estuary in Oita Prefecture, Japan. The vertical distribution of 33 elements in the sediments has been determined and compared with that in more polluted estuarine sediments. While the S content increased with increasing depth because of a sulphide accumulation under reducing condition, the increase in sulphide-forming elements such as Ag, Cd, Co and Zn was not observed in the deeper section of the Yasaka River estuarine sediments. (author)

  19. 210Po determination in estuarine sediments from Baixada Santista, SP - Brazil

    International Nuclear Information System (INIS)

    Ramos, Guilherme da F.; Silva, Paulo S.C. da; Mazzilli, Barbara P.; Damatto, Sandra R.

    2009-01-01

    The objective of the present work is to determine 210 Po activity concentration in estuarine sediments from Baixada Santista. The area comprehends nine cities in the Brazilian coast (Bertioga, Guaruja, Santos, Sao Vicente, Cubatao, Praia Grande, Mongagua, Itanhaem and Peruibe). It is one of the most important industrial areas in Brazil due to the large number of industries operating in Cubatao, such as steel, petrochemical and fertilizer industries. That, together with a large population, causes a negative impact on marine biota. The cores were obtained from Sao Vicente and Bertioga by extracting profiles up to 1 meter depth with a Piston core sampler. The samples were prepared and treated with both physical and chemical processes. The physical processes include drying, grinding and sieving. The chemical preparation consists of a series of acid digestion till total dissolution and destruction of organic matter. After the acid digestion, the samples were filtered and evaporated till dryness. The residue was then dissolved in HCl 6.25 M. Po was spontaneously deposited in mirror finished silver disc, for 2 hours at 90 deg C and constant agitation. The disc was then counted in a surface barrier alpha detector for 200,000 seconds. Three cores were analyzed so far, two from Sao Vicente and one from Bertioga. (author)

  20. Human hepatoma cells exposed to estuarine sediment contaminant extracts permitted the differentiation between cytotoxic and pro-mutagenic fractions

    International Nuclear Information System (INIS)

    Pinto, M.; Costa, P.M.; Louro, H.; Costa, M.H.; Lavinha, J.

    2014-01-01

    Complex toxicant mixtures present in estuarine sediments often render contaminant screening unfeasible and compromise determining causation. HepG2 cells were subjected to bioassays with sediment extracts obtained with a series of progressively polar solvents plus a crude extract. The sediments were collected from an impacted area of an estuary otherwise regarded as pristine, whose stressors result mostly from aquaculture effluents and hydrodynamic shifts that enhance particle deposition. Compared to a reference scenario, the most polar extracts yielded highest cytotoxicity while higher genotoxicity (including oxidative damage) was elicited by non-polar solvents. While the former caused effects similar to those expected from biocides, the latter triggered effects compatible with known pro-mutagens like PAHs, even though the overall levels of toxicants were considered of low risk. The results indicate that the approach may constitute an effective line-of-evidence to infer on the predominant set of hazardous contaminants present in complex environmental mixtures. -- Highlights: • Estuarine sediment contaminants were extracted with different organic solvents. • More polar solvents contained the most cytotoxic contaminant fraction. • Non-polar solvents extracted the main genotoxic component of the mixture. • DNA base oxidation was detected through FPG/Comet assay. • The contamination pattern could be inferred from cytoassays with HepG2 cells. -- Polar/non-polar sediment fractions elicited differential cytotoxic and genotoxic effects in human HepG2 cells

  1. Estimation of settling velocity of sediment particles in estuarine and coastal waters

    Science.gov (United States)

    Nasiha, Hussain J.; Shanmugam, Palanisamy

    2018-04-01

    A model for estimating the settling velocity of sediment particles (spherical and non-spherical) in estuarine and coastal waters is developed and validated using experimental data. The model combines the physical, optical and hydrodynamic properties of the particles and medium to estimate the sediment settling velocity. The well-known Stokes law is broadened to account for the influencing factors of settling velocity such as particle size, shape and density. To derive the model parameters, laboratory experiments were conducted using natural flaky seashells, spherical beach sands and ball-milled seashell powders. Spectral light backscattering measurements of settling particles in a water tank were made showing a distinct optical feature with a peak shifting from 470-490 nm to 500-520 nm for particle populations from spherical to flaky grains. This significant optical feature was used as a proxy to make a shape determination in the present model. Other parameters experimentally determined included specific gravity (ΔSG) , Corey shape factor (CSF) , median grain diameter (D50) , drag coefficient (Cd) and Reynolds number (Re) . The CSF values considered ranged from 0.2 for flaky to 1.0 for perfectly spherical grains and Reynolds numbers from 2.0 to 105 for the laminar to turbulent flow regimes. The specific gravity of submerged particles was optically derived and used along with these parameters to estimate the sediment settling velocity. Comparison with the experiment data showed that the present model estimated settling velocities of spherical and non-spherical particles that were closely consistent with the measured values. Findings revealed that for a given D50, the flaky particles caused a greater decrease in settling velocity than the spherical particles which suggests that the particle shape factor has a profound role in influencing the sediment settling velocity and drag coefficients, especially in transitional and turbulent flow regimes. The present model can

  2. Radiocarbon dating, chronologic framework, and changes in accumulation rates of holocene estuarine sediments from Chesapeake Bay

    Science.gov (United States)

    Colman, Steven M.; Baucom, P.C.; Bratton, J.F.; Cronin, T. M.; McGeehin, J.P.; Willard, D.; Zimmerman, A.R.; Vogt, P.R.

    2002-01-01

    Rapidly accumulating Holocene sediments in estuaries commonly are difficult to sample and date. In Chesapeake Bay, we obtained sediment cores as much as 20 m in length and used numerous radiocarbon ages measured by accelarator mass spectrometry methods to provide the first detailed chronologies of Holocene sediment accumulation in the bay. Carbon in these sediments is a complex mixture of materials from a variety of sources. Analyses of different components of the sediments show that total organic carbon ages are largely unreliable, because much of the carbon (including coal) has been transported to the bay from upstream sources and is older than sediments in which it was deposited. Mollusk shells (clams, oysters) and foraminifera appear to give reliable results, although reworking and burrowing are potential problems. Analyses of museum specimens collected alive before atmospheric nuclear testing suggest that the standard reservoir correction for marine samples is appropriate for middle to lower Chesapeake Bay. The biogenic carbonate radiocarbon ages are compatible with 210 Pb and 137 Cs data and pollen stratigraphy from the same sites. Post-settlement changes in sediment transport and accumulation is an important environmental issue in many estuaries, including the Chesapeake. Our data show that large variations in sediment mass accumulation rates occur among sites. At shallow water sites, local factors seem to control changes in accumulation rates with time. Our two relatively deep-water sites in the axial channel of the bay have different long-term average accumulation rates, but the history of sediment accumulation at these sites appears to reflect overall conditions in the bay. Mass accumulation rates at the two deep-water sites rapidly increased by about fourfold coincident with widespread land clearance for agriculture in the Chesapeake watershed.

  3. Cumulative influences of a small city and former mining activities on the sediment quality of a subtropical estuarine protected area.

    Science.gov (United States)

    Cruz, Ana Carolina Feitosa; Davanso, Marcela Bergo; Araujo, Giuliana Seraphim; Buruaem, Lucas M; Santaella, Sandra Tédde; de Morais, Rodofley Davino; Abessa, Denis M S

    2014-11-01

    This study aimed to evaluate the sediment quality in the estuarine protected area known as Cananéia-Iguape-Peruíbe (CIP-PA), located on the southeastern coast of Brazil. The study was designed considering possible negative effects induced by the city of Cananéia on the sediment quality of surrounding areas. This evaluation was performed using chemical and ecotoxicological analyses. Sediments were predominantly sandy, with low CaCO3 contents. Amounts of organic matter varied, but higher contents occurred closer to the city, as well as did Fe and Total Recoverable Oils and Greases (TROGs) concentrations. Contamination by Cd and Cu was revealed in some samples, while concentrations of Zn were considered low. Chronic toxicity was detected in all tested sediments and acute toxicity occurred only in sediments collected near the city. The principal component analysis (PCA) revealed an association among Cd, Cu, Fe, TROG, fines, organic matter, CaCO3, and chronic toxicity, whereas acute toxicity was found to be associated with Zn and mud. However, because Zn levels were low, acute toxicity was likely due to a contaminant that was not measured. Results show that there is a broad area within the CIP-PA that is under the influence of mining activities (chronic toxicity, moderate contamination by metals), whereas poorer conditions occur closer to Cananéia (acute toxicity); thus, the urban area seems to constitute a relevant source of contaminants for the estuarine complex. These results show that contamination is already capable of producing risks for the local aquatic biota, which suggests that the CIP-PA effectiveness in protecting estuarine biota may be threatened.

  4. Simulation of the fate of faecal bacteria in estuarine and coastal waters based on a fractionated sediment transport model

    Science.gov (United States)

    Yang, Chen; Liu, Ying

    2017-08-01

    A two-dimensional depth-integrated numerical model is refined in this paper to simulate the hydrodynamics, graded sediment transport process and the fate of faecal bacteria in estuarine and coastal waters. The sediment mixture is divided into several fractions according to the grain size. A bed evolution model is adopted to simulate the processes of the bed elevation change and sediment grain size sorting. The faecal bacteria transport equation includes enhanced source and sink terms to represent bacterial kinetic transformation and disappearance or reappearance due to sediment deposition or re-suspension. A novel partition ratio and dynamic decay rates of faecal bacteria are adopted in the numerical model. The model has been applied to the turbid water environment in the Bristol Channel and Severn estuary, UK. The predictions by the present model are compared with field data and those by non-fractionated model.

  5. Depositional record of trace metals and degree of contamination in core sediments from the Mandovi estuarine mangrove ecosystem, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Veerasingam, S.; Vethamony, P.; ManiMurali, R.; Fernandes, B.

    of sources. Enrichment of metals in bottom sediments represents a critical measure of health for any mangrove ecosystem (Janaki-Raman et al., 2007). Trace metals in coastal and estuarine sediments are incorporated into the aquatic food webs through primary... of susceptibility of the particles to the processes of physical and chemical weathering. The different morphological forms of iron oxides are well correlated with the sediment horizons. Spherical iron oxides predominate in the upper layers of sediment profiles...

  6. Organic matter - A key factor in controlling mercury distribution in estuarine sediment

    Digital Repository Service at National Institute of Oceanography (India)

    Chakraborty, P.; Sarkar, A.; Vudamala, K.; Naik, R.; Nath, B.N.

    were analyzed for total carbon (TC), total inorganic carbon (TIC), total nitrogen (TN) content. TC and TN in sediments were determined using Flash 2000 CHN-elemental analyzer (Thermo Fisher Scientific Incorporation). Precision of the analysis... was within ± 5 %. Soil NC was used as certified reference material. TIC was determined by coulometry (UIC coulometrics). Anhydrated calcium carbonate was used as standard material. Relative standard deviation of the analysis was within ± 2 %. Total organic...

  7. Measuring hypoxia induced metal release from highly contaminated estuarine sediments during a 40 day laboratory incubation experiment

    Energy Technology Data Exchange (ETDEWEB)

    Banks, Joanne L., E-mail: jlbanks@student.unimelb.edu.au [Department of Zoology, University of Melbourne, Victoria, 3010 Australia (Australia); Ross, D. Jeff, E-mail: Jeff.Ross@utas.edu.au [Institute of Marine and Antarctic Studies, Nubeena Crescent, Taroona, Tasmania, 7053 Australia (Australia); Keough, Michael J., E-mail: mjkeough@unimelb.edu.au [Department of Zoology, University of Melbourne, Victoria, 3010 Australia (Australia); Eyre, Bradley D., E-mail: bradley.eyre@scu.edu.au [Centre for Coastal Biogeochemistry, School of Environmental Science and Management, Southern Cross University, PO Box 157, Lismore, NSW, 2480 Australia (Australia); Macleod, Catriona K., E-mail: Catriona.Macleod@utas.edu.au [Institute of Marine and Antarctic Studies, Nubeena Crescent, Taroona, Tasmania, 7053 Australia (Australia)

    2012-03-15

    Nutrient inputs to estuarine and coastal waters worldwide are increasing and this in turn is increasing the prevalence of eutrophication and hypoxic and anoxic episodes in these systems. Many urbanised estuaries are also subject to high levels of anthropogenic metal contamination. Environmental O{sub 2} levels may influence whether sediments act as sinks or sources of metals. In this study we investigated the effect of an extended O{sub 2} depletion event (40 days) on fluxes of trace metals (and the metalloid As) across the sediment-water interface in sediments from a highly metal contaminated estuary in S.E. Tasmania, Australia. We collected sediments from three sites that spanned a range of contamination and measured total metal concentration in the overlying water using sealed core incubations. Manganese and iron, which are known to regulate the release of other divalent cations from sub-oxic sediments, were released from sediments at all sites as hypoxia developed. In contrast, the release of arsenic, cadmium, copper and zinc was comparatively low, most likely due to inherent stability of these elements within the sediments, perhaps as a result of their refractory origin, their association with fine-grained sediments or their being bound in stable sulphide complexes. Metal release was not sustained due to the powerful effect of metal-sulphide precipitation of dissolved metals back into sediments. The limited mobilisation of sediment bound metals during hypoxia is encouraging, nevertheless the results highlight particular problems for management in areas where hypoxia might occur, such as the release of metals exacerbating already high loads or resulting in localised toxicity. - Highlights: Black-Right-Pointing-Pointer Metal contaminated sediments exposed to long-term hypoxia released Mn and Fe pulses. Black-Right-Pointing-Pointer As flux increased under anoxic conditions Cd, Cu and Zn fluxes occurred only during the first week of hypoxia. Black

  8. Anthropogenic Influences on Estuarine Sedimentation and Ecology: Examples from Varved Sediments of the Pettaquamscutt River Estuary, Rhode Island

    Science.gov (United States)

    Estuaries and lakes are undergoing anthropogenic alterations as development and industry intensify in the modern world. Assessing the ecological health of such water bodies is difficult because accurate accounts of pre-anthropogenic estuarine/lacustrine conditions do not exist. ...

  9. Clay mineralogy and source-to-sink transport processes of Changjiang River sediments in the estuarine and inner shelf areas of the East China Sea

    Science.gov (United States)

    Zhao, Yifei; Zou, Xinqing; Gao, Jianhua; Wang, Chenglong; Li, Yali; Yao, Yulong; Zhao, Wancang; Xu, Min

    2018-02-01

    We examined the source-to-sink sediment transport processes from the Changjiang River to the estuarine coastal shelf area by analyzing the clay mineral assemblages in suspended sediment samples from the Changjiang River catchment and surface samples from the estuarine coastal shelf area following the impoundment of the Three Gorges Dam (TGD) in 2003. The results indicate that the clay mineral compositions throughout the study area are dominated by illite, with less abundant kaolinite and chlorite and scarce smectite. The clay minerals display distinct differences in the tributaries and exhibit obvious changes in the trunk stream compared with the periods before 2003, and the source of sediment has largely shifted to the mid- to lower reaches of the river after 2003. Spatially, the clay mineral assemblages in the estuarine area define two compositionally distinct provinces. Province I covers the mud area of the Changjiang River estuary and the Zhe-Min coastal region, where sediment is primarily supplied by the Changjiang River. Province II includes part of the Changjiang River estuary and the southeastern portion of the study area, where the sediment is composed of terrestrial material from the Changjiang River and re-suspended material from the Huanghe River carried by the Jiangsu coastal current. Moreover, the other smaller rivers in China (including the Oujiang and Minjiang rivers of mainland China and the rivers of West Taiwan) also contribut sediments to the estuarine and inner shelf areas. In general, the clay mineral assemblages in the Changjiang River estuarine area are have mainly been controlled by sediment supplied from upstream of the Changjiang River tributaries. However, since the completion of the TGD in 2003, the mid- to downstream tributaries have become the main source of sediments from the Changjiang catchment into the East China Sea. These analyses further demonstrate that the coastal currents and the decrease in the sediment load of the river

  10. Measuring hypoxia induced metal release from highly contaminated estuarine sediments during a 40 day laboratory incubation experiment

    International Nuclear Information System (INIS)

    Banks, Joanne L.; Ross, D. Jeff; Keough, Michael J.; Eyre, Bradley D.; Macleod, Catriona K.

    2012-01-01

    Nutrient inputs to estuarine and coastal waters worldwide are increasing and this in turn is increasing the prevalence of eutrophication and hypoxic and anoxic episodes in these systems. Many urbanised estuaries are also subject to high levels of anthropogenic metal contamination. Environmental O 2 levels may influence whether sediments act as sinks or sources of metals. In this study we investigated the effect of an extended O 2 depletion event (40 days) on fluxes of trace metals (and the metalloid As) across the sediment–water interface in sediments from a highly metal contaminated estuary in S.E. Tasmania, Australia. We collected sediments from three sites that spanned a range of contamination and measured total metal concentration in the overlying water using sealed core incubations. Manganese and iron, which are known to regulate the release of other divalent cations from sub-oxic sediments, were released from sediments at all sites as hypoxia developed. In contrast, the release of arsenic, cadmium, copper and zinc was comparatively low, most likely due to inherent stability of these elements within the sediments, perhaps as a result of their refractory origin, their association with fine-grained sediments or their being bound in stable sulphide complexes. Metal release was not sustained due to the powerful effect of metal-sulphide precipitation of dissolved metals back into sediments. The limited mobilisation of sediment bound metals during hypoxia is encouraging, nevertheless the results highlight particular problems for management in areas where hypoxia might occur, such as the release of metals exacerbating already high loads or resulting in localised toxicity. - Highlights: ► Metal contaminated sediments exposed to long-term hypoxia released Mn and Fe pulses. ► As flux increased under anoxic conditions Cd, Cu and Zn fluxes occurred only during the first week of hypoxia. ► Flux of these metals from 3 sites was not related to total sediment metal

  11. Impacts of Suspended Sediment and Estuarine - Shelf Exchange Pathways on Shelf Ecosystem Dynamics in the Northern Gulf of Mexico

    Science.gov (United States)

    Wiggert, J. D.; Pan, C.; Dinniman, M. S.; Lau, Y.; Fitzpatrick, P. J.; O'Brien, S. J.; Bouchard, C.; Quas, L. M.; Miles, T. N.; Cambazoglu, M. K.; Dykstra, S. L.; Dzwonkowski, B.; Jacobs, G. A.; Church, I.; Hofmann, E. E.

    2017-12-01

    A circulation model based on the Coupled-Ocean-Atmosphere-Wave-Sediment Transport (COAWST) Modeling System, with coupled biogeochemical and sediment transport modules, has been implemented for Mississippi Sound and the adjacent continental shelf region. The model has 400-m horizontal resolution, 24 vertical layers, and includes wetting/drying capability to resolve shallow inshore regions. The circulation model was spun-up using oceanographic initial and lateral boundary conditions provided by a 1-km resolution regional implementation of the Navy Coastal Ocean Model (NCOM) in the Gulf of Mexico. The biogeochemical module includes multiple size classes of phytoplankton, zooplankton and detritus, a fish larvae compartment, and explicitly tracks dissolved oxygen with benthic cycling interaction. The sediment transport model is implemented based on benthic mapping data that provides bottom sediment type distributions and spatio-temporal validation. A regionally specific atmospheric forcing product that provides improved spatial and temporal resolution, including diurnal sea breeze impacts, has been developed and applied. Model experiments focus on periods when comprehensive ship-based sampling was deployed by the CONCORDE (Consortium for Coastal River-Dominated Ecosystems) research program, which was established to investigate the complex fine-scale biological, chemical and physical interactions in a marine system controlled by pulsed-river plume dynamics. Biophysical interactions and biogeochemical variability associated with estuarine - shelf exchanges between nearshore lagoonal estuarine waters and the continental shelf revealed by the model provide new insight into how seasonal variation of hydrological forcing conditions influence ecological and biogeochemical processes in the highly productive Northern Gulf region. Application of the COAWST-based model system with and without inclusion of the sediment transport module demonstrates how suspended sediment in the

  12. RESPONSE OF GHOST SHRIMP (NEOTRYPAEA CALIFORNIENSIS) BIOTURBATION TO ORGANIC MATTER ENRICHMENT OF ESTUARINE INTERTIDAL SEDIMENTS

    Science.gov (United States)

    Populations of burrowing shrimp (Neotrypaea californiensis and Upogebia p;ugettensis) are the dominant invertebrate fauna on Pacific estuarine tide flats, occupying >80% of intertidal area in some estuaries. Burrowing shrimp are renowned for their bioturbation of intertidal sedi...

  13. Metabolism of reduced methylated sulfur compounds in anaerobic sediments and by a pure culture of an estuarine methanogen

    International Nuclear Information System (INIS)

    Kiene, R.P.; Oremland, R.S.; Catena, A.; Miller, L.G.; Capone, A.G.

    1986-01-01

    Addition of dimethylsulfide (DMS), dimethyldisulfide (DMDS), or methane thiol (MSH) to a diversity of anoxic aquatic sediments (e.g., fresh water, estuarine, alkaline/hypersaline) stimulated methane production. The yield of methane recovered from DMS was often 52 to 63%, although high concentrations of DMS (as well as MSH and DMDS) inhibited methanogenesis in some types of sediments. Production of methane from these reduced methylated sulfur compounds was blocked by 2-bromoethanesulfonic acid. Sulfate did not influence the metabolism of millimolar levels of DMS, DMDs, or MSH added to sediments. However, when DMS was added at ∼2-3=M levels as [ 14 C]DMS, metabolism by sediments resulted in a 14 CH 4 / 14 CO 2 ratio of only 0.06. Addition of molybdate increased the ratio of 1.8, while 2-bromoethanesulfonic acid decreased it to 0, but did not block 14 CO 2 production. These results indicate the methanogens and sulfate reducers compete for DMS when it is present at low concentrations; however, at high concentrations, DMS is a noncompetitive substrate for methanogens. Metabolism of DMS by sediments resulted in the appearance of MSH as a transient intermediate. A pure culture of an obligately methylotrophic estuarine methanogen was isolated which was capable of growth on DMS. Metabolism of DMS by the culture also resulted in the transient appearance of MSH, but the organism could grow on neither MSH nor DMDS. The culture metabolized [ 14 C]-DMS to yield a 14 CH 4 / 14 CO 2 ratio of ∼ 2.8

  14. Evaluation through column leaching tests of metal release from contaminated estuarine sediment subject to CO2 leakages from Carbon Capture and Storage sites

    International Nuclear Information System (INIS)

    Payán, M. Cruz; Galan, Berta; Coz, Alberto; Vandecasteele, Carlo; Viguri, Javier R.

    2012-01-01

    The pH change and the release of organic matter and metals from sediment, due to the potential CO 2 acidified seawater leakages from a CCS (Carbon Capture and Storage) site are presented. Column leaching test is used to simulate a scenario where a flow of acidified seawater is in contact with recent contaminated sediment. The behavior of pH, dissolved organic carbon (DOC) and metals As, Cd, Cr, Cu, Ni, Pb, Zn, with liquid to solid (L/S) ratio and pH is analyzed. A stepwise strategy using empirical expressions and a geochemical model was conducted to fit experimental release concentrations. Despite the neutralization capacity of the seawater-carbonate rich sediment system, important acidification and releases are expected at local scale at lower pH. The obtained results would be relevant as a line of evidence input of CCS risk assessment, in an International context where strategies to mitigate the climate change would be applied. - Highlights: ► Tier structured approach for assessment of the release of metals from sediment. ► Standard column leaching test to simulate CO 2 acidified seawater CCS leakages. ► Metal and DOC release from marine sediment in contact to CO 2 acidified seawater. ► From empirical to geochemical modeling approaches of DOC and metals release in column tests. ► Contamination line of evidence input of CCS risk assessment. - Column metal release from CO 2 acidified seawater leakages in contact with estuarine contaminated sediment in CCS sites

  15. Micro-spatial variation of elemental distribution in estuarine sediment and their accumulation in mangroves of Indian Sundarban.

    Science.gov (United States)

    Bakshi, Madhurima; Ram, S S; Ghosh, Somdeep; Chakraborty, Anindita; Sudarshan, M; Chaudhuri, Punarbasu

    2017-05-01

    This work describes the micro-spatial variation of elemental distribution in estuarine sediment and bioaccumulation of those elements in different mangrove species of the Indian Sundarbans. The potential ecological risk due to such elemental load on this mangrove-dominated habitat is also discussed. The concentrations of elements in mangrove leaves and sediments were determined using energy-dispersive X-ray fluorescence spectroscopy. Sediment quality and potential ecological risks were assessed from the calculated indices. Our data reflects higher concentration of elements, e.g., Al, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, and Pb, in the sediment, as compared to that reported by earlier workers. Biological concentration factors for K, Ca, Mn, Fe, Cu, and Zn in different mangroves indicated gradual elemental bioaccumulation in leaf tissues (0.002-1.442). Significant variation was observed for elements, e.g., Ni, Mn, and Ca, in the sediments of all the sites, whereas in the plants, significant variation was found for P, S, Cl, K, Ca, Mn, Fe, Cu, and Zn. This was mostly due to the differences in uptake and accumulation potential of the plants. Various sediment quality indices suggested the surface sediments to be moderately contaminated and suffering from progressive deterioration. Cu, Cr, Zn, Mn, and Ni showed higher enrichment factors (0.658-1.469), contamination factors (1.02-2.7), and geo-accumulation index (0.043-0.846) values. The potential ecological risk index values considering Cu, Cr, Pb, and Zn were found to be within "low ecological risk" category (20.04-24.01). However, Cr and Ni in the Sundarban mangroves exceeded the effect range low and probable effect level limits. Strong correlation of Zn with Fe and K was observed, reflecting their similar transportation and accumulation process in both sediment and plant systems. The plant-sediment elemental correlation was found to be highly non-linear, suggesting role of some physiological and edaphic factors in

  16. Estuarine bed-sediment-quality data collected in New Jersey and New York after Hurricane Sandy, 2013

    Science.gov (United States)

    Fischer, Jeffrey M.; Phillips, Patrick J.; Reilly, Timothy J.; Focazio, Michael J.; Loftin, Keith A.; Benzel, William M.; Jones, Daniel K.; Smalling, Kelly L.; Fisher, Shawn C.; Fisher, Irene J.; Iwanowicz, Luke R.; Romanok, Kristin M.; Jenkins, Darkus E.; Bowers, Luke; Boehlke, Adam; Foreman, William T.; Deetz, Anna C.; Carper, Lisa G.; Imbrigiotta, Thomas E.; Birdwell, Justin E.

    2015-01-01

    This report describes a reconnaissance study of estuarine bed-sediment quality conducted June–October 2013 in New Jersey and New York after Hurricane Sandy in October 2012 to assess the extent of contamination and the potential long-term human and ecological impacts of the storm. The study, funded through the Disaster Relief Appropriations Act of 2013 (PL 113-2), was conducted by the U.S. Geological Survey in cooperation with the U.S. Environmental Protection Agency and the National Oceanographic and Atmospheric Administration. In addition to presenting the bed-sediment-quality data, the report describes the study design, documents the methods of sample collection and analysis, and discusses the steps taken to assure the quality of the data.

  17. Occurrence of perfluorinated alkyl substances in sediment from estuarine and coastal areas of the East China Sea.

    Science.gov (United States)

    Yan, Hong; Zhang, Chaojie; Zhou, Qi; Yang, Shouye

    2015-02-01

    Perfluorinated alkyl substances (PFAS) have drawn much attention due to their environmental persistence, ubiquitous existence, and bioaccumulation potential. The occurrence and spatial variation of PFAS were investigated through collection of riverine and marine sediments from estuarine and coastal areas of the East China Sea. Among them, perfluorooctanesulfonic acid (PFOS), perfluoroheptanoic acid (PFHpA), and perfluorooctanoic acid (PFOA) were the three predominant PFAS with the highest detection frequencies in the sediment. PFOS up to 32.4 ng g(-1) dw and ∑PFAS up to 34.8 ng g(-1) dw were detected. Compared to other studies, high levels of PFOS were found in sediments from the East China Sea. PFHpA was also detected at higher frequency and concentration than those of other studies, which suggests point sources in this area. Concentrations of PFAS in riverine sediments were much higher than in marine sediments. Analysis of spatial variations presented overall decreasing trends of PFAS from inshore to offshore areas.

  18. Assessment of the genotoxic potential of contaminated estuarine sediments in fish peripheral blood: Laboratory versus in situ studies

    International Nuclear Information System (INIS)

    Costa, Pedro M.; Neuparth, Teresa S.; Caeiro, Sandra; Lobo, Jorge; Martins, Marta; Ferreira, Ana M.; Caetano, Miguel; Vale, Carlos; Angel DelValls, T.; Costa, Maria H.

    2011-01-01

    Juvenile Senegalese soles (Solea senegalensis) were exposed to estuarine sediments through 28-day laboratory and in situ (field) bioassays. The sediments, collected from three distinct sites (a reference plus two contaminated) of the Sado Estuary (W Portugal) were characterized for total organic matter, redox potential, fine fraction and for the levels of metals, polycyclic aromatic hydrocarbons (PAHs) and organochlorines, namely polychlorinated biphenyls (PCBs) and dichloro diphenyl tricholoethane plus its main metabolites (DDTs). Genotoxicity was determined in whole peripheral blood by the single-cell gel electrophoresis (SCGE or 'comet') assay and by scoring erythrocytic nuclear abnormalities (ENA). Analysis was complemented with the determination of lipid peroxidation in blood plasma by the thiobarbituric acid reactive substances (TBARS) protocol and cell type sorting. The results showed that exposure to contaminated sediments induced DNA fragmentation and clastogenesis. Still, laboratory exposure to the most contaminated sediment revealed a possible antagonistic effect between metallic and organic contaminants that might have been enhanced by increased bioavailability. The laboratory assay caused a more pronounced increase in ENA whereas a very significant increase in DNA fragmentation was observed in field-tested fish exposed to the reference sediment, which is likely linked to increased lipid peroxidation that probably occurred due to impaired access to food. Influence of natural pathogens was ruled out by unaltered leukocyte counts. The statistical integration of data correlated lipid peroxidation with biological variables such as fish length and weight, whereas the genotoxicity biomarkers were more correlated to sediment contamination. It was demonstrated that laboratory and field bioassays for the risk assessment of sediment contamination may yield different genotoxicity profiles although both provided results that are in overall accordance with sediment

  19. Assessment of the genotoxic potential of contaminated estuarine sediments in fish peripheral blood: Laboratory versus in situ studies

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Pedro M., E-mail: pmcosta@fct.unl.pt [IMAR-Instituto do Mar, Departamento de Ciencias e Engenharia do Ambiente, Faculdade de Ciencias e Tecnologia da Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Neuparth, Teresa S. [CIIMAR-Centro Interdisciplinar de Investigacao Marinha e Ambiental, Laboratorio de Toxicologia Ambiental, Universidade do Porto, Rua dos Bragas 289, 4050-123 Porto (Portugal); Caeiro, Sandra [IMAR-Instituto do Mar, Departamento de Ciencias e Engenharia do Ambiente, Faculdade de Ciencias e Tecnologia da Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Departamento de Ciencias e Tecnologia, Universidade Aberta, Rua da Escola Politecnica, 141, 1269-001 Lisboa (Portugal); Lobo, Jorge [IMAR-Instituto do Mar, Departamento de Ciencias e Engenharia do Ambiente, Faculdade de Ciencias e Tecnologia da Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Martins, Marta; Ferreira, Ana M.; Caetano, Miguel; Vale, Carlos [IPIMAR-INRB, Instituto Nacional dos Recursos Biologicos, Avenida de Brasilia, 1449-006 Lisboa (Portugal); Angel DelValls, T. [UNESCO/UNITWIN/WiCop Chair-Departamento de Quimica Fisica, Facultad de Ciencias del Mar y Ambientales, Universidad de Cadiz, Poligono rio San Pedro s/n, 11510 Puerto Real, Cadiz (Spain); Costa, Maria H. [IMAR-Instituto do Mar, Departamento de Ciencias e Engenharia do Ambiente, Faculdade de Ciencias e Tecnologia da Universidade Nova de Lisboa, 2829-516 Caparica (Portugal)

    2011-01-15

    Juvenile Senegalese soles (Solea senegalensis) were exposed to estuarine sediments through 28-day laboratory and in situ (field) bioassays. The sediments, collected from three distinct sites (a reference plus two contaminated) of the Sado Estuary (W Portugal) were characterized for total organic matter, redox potential, fine fraction and for the levels of metals, polycyclic aromatic hydrocarbons (PAHs) and organochlorines, namely polychlorinated biphenyls (PCBs) and dichloro diphenyl tricholoethane plus its main metabolites (DDTs). Genotoxicity was determined in whole peripheral blood by the single-cell gel electrophoresis (SCGE or 'comet') assay and by scoring erythrocytic nuclear abnormalities (ENA). Analysis was complemented with the determination of lipid peroxidation in blood plasma by the thiobarbituric acid reactive substances (TBARS) protocol and cell type sorting. The results showed that exposure to contaminated sediments induced DNA fragmentation and clastogenesis. Still, laboratory exposure to the most contaminated sediment revealed a possible antagonistic effect between metallic and organic contaminants that might have been enhanced by increased bioavailability. The laboratory assay caused a more pronounced increase in ENA whereas a very significant increase in DNA fragmentation was observed in field-tested fish exposed to the reference sediment, which is likely linked to increased lipid peroxidation that probably occurred due to impaired access to food. Influence of natural pathogens was ruled out by unaltered leukocyte counts. The statistical integration of data correlated lipid peroxidation with biological variables such as fish length and weight, whereas the genotoxicity biomarkers were more correlated to sediment contamination. It was demonstrated that laboratory and field bioassays for the risk assessment of sediment contamination may yield different genotoxicity profiles although both provided results that are in overall accordance with

  20. Anthropogenic Influences on Estuarine Sedimentation and Ecology: Examples from Varved Sediments of the Pettaquanscutt River Estuary, Rhode Island

    Science.gov (United States)

    Estuaries and lakes are undergoing anthropogenic alterations as development and industry intensify in the modern world. Assessing the ecological health of such water bodies is difficult because accurate accounts of pre-anthropogenic estuarine/lacustrine conditions do not exist. S...

  1. Evaluation of mercury contamination in sediments from Santos - Sao Vicente Estuarine system, in period of 1996 -2000

    International Nuclear Information System (INIS)

    Hortellani, Marcos Antonio

    2003-01-01

    The distribution of mercury contamination in the Santos - Sao Vicente Estuarine System was observed through the analysis of seventy seven surface sediments samples collected in two series. In different periods and points, since the Channel of Piacaguera, the head of the system, , through the estuarine arms of Santos and Sao Vicente as far as the Bay of Santos, about 30 Km downstream, and in different mangrove areas, including industrial and harbor influence zones. The obtained values ranged from 0.03 to 1.19 μg g -1 About 90% of the samples of the first series collected among 1997-1998 and 50% of the second series collected among 1999-2000 presented levels of Hg > 0,13 μg g -1 ,limit considered by the Canadian legislation and adopted by CETESB, below which doesn't happen adverse effect in the biological community. And about 35% of samples of the first series and 11 % of the second series presented concentrations of Hg > 0.698 μg g -1 probable level of occurrence of adverse effect in the biological community. These results indicate an increase of the mercury levels caused by the industrial, port and urban activities. The mercury concentration in sediments was determined by using an Atomic Absorption Spectrophotometer, coupling with a flow injection system by a cold vapor generation, using a manual injection valve (FIA-CVAAS). The estimate of the uncertainties associated to this procedure was calculated. The following elements were also determined: Fe, Al, Zn, Ni, Pb, Cd, Cr and Co in 46 samples of the second series, by atomic absorption spectrometry. In order to verify possible relationship among all the investigated elements in the samples sediments, was carried out a statistical study, using the SPSS-8.0 software. Pearson correlation and Principal Component's analysis were used for with the objective to identify of major relationship for additional exploration of the general behavior of the data. (author)

  2. Use of mineral magnetic concentration data as a particle size proxy: a case study using marine, estuarine and fluvial sediments in the Carmarthen Bay area, South Wales, U.K.

    Science.gov (United States)

    Booth, C A; Walden, J; Neal, A; Smith, J P

    2005-07-15

    Compositional (non-magnetic) data can correlate strongly with particle size, which deems it appropriate as a particle size proxy and, therefore, a reliable means of normalising analytical data for particle size effects. Previous studies suggest magnetic concentration parameters represent an alternative means of normalising for these effects and, given the speed, low-cost and sensitivity of the measurements may, therefore, offer some advantages over other compositional signals. In this work, contemporary sediments from a range of depositional environments have been analysed with regard to their mineral magnetic concentration and textural characteristics, to observe if the strength and nature of the relationship identified in previous studies is universal. Our data shows magnetic parameters (chi(LF), chi(ARM) and SIRM) possess contrasting relationships with standard textural parameters for sediment samples collected from marine (Carmarthen Bay), estuarine (Gwendraeth Estuary) and fluvial (Rivers Gwendraeth Fach and Gwendraeth Fawr) settings. Magnetic concentrations of sediments from both the marine and estuarine environments are highly influenced by the magnetic contribution of finer particle sizes; Gwendraeth Fawr River sediments are influenced by the magnetic contribution of coarser particle sizes, while sediments from the Gwendraeth Fach River are not influenced significantly by any variations in textural properties. These results indicate mineral magnetic measurements have considerable potential as a particle size proxy for particular sedimentary environments, which in certain instances could be useful for geochemical, sediment transport, and sediment provenance studies. However, the data also highlight the importance of fully determining the nature of the relationship between sediment particle size and magnetic properties before applying mineral magnetic data as a particle size proxy.

  3. An inversion of the estuarine circulation by sluice water discharge and its impact on suspended sediment transport

    Science.gov (United States)

    Schulz, Kirstin; Gerkema, Theo

    2018-01-01

    The Wadden Sea is characterized by a complex topography of branching channels and intertidal flats, in which the interplay between fresh water discharges, wind forcing and the tidal current causes sediment transport rates and direction to be highly variable in space and time. During three field campaigns, indications of a negative estuarine circulation have been found in a channel adjacent to the coast in the Western Dutch Wadden Sea. Contrary to the classical picture of estuarine circulation, a periodic density stratification was observed that builds up during flood and breaks down during ebb. This can be related to a large freshwater source at the mouth of the channel, the sluice in Kornwerderzand. In this study, observations of this phenomenon are presented, and with the help of a numerical model the different drivers for residual suspended matter transport in this area, namely tidal asymmetries in the current velocity and the above mentioned periodic stratification, are investigated. It is found that the residual current in the area of interest points in ebb direction, caused by both the elongated ebb flow phase and the periodic stratification. On the contrary, the stronger flood currents cause a transport of suspended matter in flood direction. This transport is counteracted and therefore diminished by the effects of the sluice discharge.

  4. An in situ postexposure feeding assay with Carcinus maenas for estuarine sediment-overlying water toxicity evaluations.

    Science.gov (United States)

    Moreira, Susana M; Moreira-Santos, Matilde; Guilhermino, Lúcia; Ribeiro, Rui

    2006-01-01

    This study developed and evaluated a short-term sublethal in situ toxicity assay for estuarine sediment-overlying waters, with the crab Carcinus maenas (L.) based on postexposure feeding. It consisted of a 48-h in situ exposure period followed by a short postexposure feeding period (30 min). A precise method for quantifying feeding, using the Polychaeta Hediste (Nereis) diversicolor Müller as food source, was first developed. The sensitivity of the postexposure feeding response was verified by comparing it to that of lethality, upon cadmium exposure. The influence of environmental conditions prevailing during exposure (salinity, temperature, substrate, light regime, and food availability) on postexposure feeding was also addressed. The potential of this in situ assay was then investigated by deploying organisms at ten sites, located in reference and contaminated Portuguese estuaries. Organism recovery ranged between 90% and 100% and a significant postexposure feeding depression (16.3-72.7%) was observed at all contaminated sites relatively to references.

  5. Activity, Microenvironments, and Community Structure of Aerobic and Anaerobic Ammonium Oxidizing Prokaryotes in Estuarine Sediment (Randers Fjord, DK)

    DEFF Research Database (Denmark)

    Schramm, Andreas; Revsbech, Niels Peter; Dalsgaard, Tage

    2006-01-01

    ACTIVITY, MICROENVIRONMENTS, AND COMMUNITY STRUCTURE OF AEROBIC AND ANAEROBIC AMMONIUM OXIDIZING PROKARYOTES IN ESTUARINE SEDIMENT (RANDERS FJORD, DK) A. Schramm 1, N.P. Revsbech 1, T. Dalsgaard 2, E. Piña-Ochoa 3, J. de la Torré 4, D.A. Stahl 4, N. Risgaard-Petersen 2 1 Department of Biological...... conversion of ammonium with nitrite to N2, is increasingly recognized as link in the aquatic nitrogen cycle. However, factors regulating the occurrence and activity of anammox bacteria are still poorly understood. Besides the influence of abiotic factors, anammox might be controlled by either aerobic ammonia...... oxidizing bacteria and archaea (AOB and AOA) or nitrate-reducing/denitrifying bacteria via their supply of nitrite. Along the Randers Fjord estuary (Denmark), gradients of salinity, nutrients, and organic loading can be observed, and anammox has been detected previously at some sites. The aim of this study...

  6. Multi-elemental contamination and historic record in sediments from the Santos-Cubatao Estuarine System, Brazil

    International Nuclear Information System (INIS)

    Luiz-Silva, Wanilson; Machado, Wilson; Matos, Rosa H.R.

    2008-01-01

    This paper records for the first time the contamination history and identifies the sources of 38 elements in sediments from the Santos-Cubatao Estuarine System (SE Brazil), at one of the most industrialized areas in Latin America. The compositions of samples from a 260 cm long sediment core collected in the Morrao River estuary were determined by ICP-MS. Enrichment factors, principal component analysis, correlation matrixes, and the characterization of geochemical signatures permitted a consistent data evaluation. Contaminant elements such as Cr, Mn, Ni, Zn, Ga, Ag, Cd, Sn, Sb, Pb, and Bi were associated with steel plant-derived Fe concentrations, while Be, Ca, Sc, Co, Cu, Sr, Y, Zr, Nb, Hf, Ta, Th, and U were associated with fertilizer industry-derived P concentrations. An overlap of sedimentary Fe distribution and local steel plant production indicated that Fe is a reliable marker of the contamination history, allowing the estimation of sedimentation rates over a period of 45 years of industrial activities. (author)

  7. Development of a hybrid pollution index for heavy metals in marine and estuarine sediments.

    Science.gov (United States)

    Brady, James P; Ayoko, Godwin A; Martens, Wayde N; Goonetilleke, Ashantha

    2015-05-01

    Heavy metal pollution of sediments is a growing concern in most parts of the world, and numerous studies focussed on identifying contaminated sediments by using a range of digestion methods and pollution indices to estimate sediment contamination have been described in the literature. The current work provides a critical review of the more commonly used sediment digestion methods and identifies that weak acid digestion is more likely to provide guidance on elements that are likely to be bioavailable than other traditional methods of digestion. This work also reviews common pollution indices and identifies the Nemerow Pollution Index as the most appropriate method for establishing overall sediment quality. Consequently, a modified Pollution Index that can lead to a more reliable understanding of whole sediment quality is proposed. This modified pollution index is then tested against a number of existing studies and demonstrated to give a reliable and rapid estimate of sediment contamination and quality.

  8. Effects of thiamphenicol on nitrate reduction and N2O release in estuarine and coastal sediments

    International Nuclear Information System (INIS)

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

    2016-01-01

    Nitrate overload is an important driver of water pollution in most estuarine and coastal ecosystems, and thus nitrate reduction processes have attracted considerable attention. Antibiotics contamination is also an emerging environmental problem in estuarine and coastal regions as a result of growing production and usage of antibiotics. However, the effects of antibiotics on nitrate reduction remain unclear in these aquatic ecosystems. In this study, continuous-flow experiments were conducted to examine the effects of thiamphenicol (TAP, a common chloramphenicol antibiotic) on nitrate reduction and greenhouse gas N 2 O release. Functional genes involved in nitrogen transformation were also quantified to explore the microbial mechanisms of the TAP influence. Production of N 2 were observed to be inhibited by TAP treatment, which implied the inhibition effect of TAP on nitrate reduction processes. As intermediate products of nitrogen transformation processes, nitrite and N 2 O were observed to accumulate during the incubation. Different TAP inhibition effects on related functional genes may be the microbial mechanism for the changes of nutrient fluxes, N 2 fluxes and N 2 O release rates. These results indicate that the antibiotics residues in estuarine and coastal ecosystems may contribute to nitrate retention and N 2 O release, which could be a major factor responsible for eutrophication and greenhouse effects. - Highlights: • Production of N 2 are inhibited by the TAP treatment. • Accumulation of nitrite and N 2 O is stimulated by TAP treatment. • Different TAP effects on functional genes may be the microbial mechanism. - TAP inhibits the production of N 2 and stimulates the accumulation of nitrite and N 2 O due to its different inhibition effects on functional genes.

  9. A Random Forest Approach to Predict the Spatial Distribution of Sediment Pollution in an Estuarine System

    Science.gov (United States)

    Modeling the magnitude and distribution of sediment-bound pollutants in estuaries is often limited by incomplete knowledge of the site and inadequate sample density. To address these modeling limitations, a decision-support tool framework was conceived that predicts sediment cont...

  10. Super(210) Pb based trace element fluxes in the nearshore and estuarine sediments off Bombay, India

    Digital Repository Service at National Institute of Oceanography (India)

    Sharma, P.; Borole, D.V.; Zingde, M.D.

    Seven sediment cores from the Thana Creek-Bombay harbour complex (THC) have been studied for excess super(210) Pb (super(210) Pb sub(exc), that portion of super(210) Pb not supported by decay of super(226) Ra in sediment), C sub(org), Mn, Fe, Co, Ni...

  11. Occurrence and behavior of butyltins in intertidal and shallow subtidal surface sediments of an estuarine beach under different sampling conditions

    Science.gov (United States)

    Santos, Dayana Moscardi dos; Sant'Anna, Bruno Sampaio; Sandron, Daniela Corsino; Cardoso de Souza, Sara; Cristale, Joyce; Marchi, Mary Rosa Rodrigues de; Turra, Alexander

    2010-07-01

    Contamination by butyltin compounds (BTs) has been reported in estuarine environments worldwide, with serious impacts on the biota of these areas. Considering that BTs can be degraded by varying environmental conditions such as incident light and salinity, the short-term variations in such factors may lead to inaccurate estimates of BTs concentrations in nature. Therefore, the present study aimed to evaluate the possibility that measurements of BTs in estuarine sediments are influenced by different sampling conditions, including period of the day (day or night), tidal zone (intertidal or subtidal), and tides (high or low). The study area is located on the Brazilian southeastern coast, São Vicente Estuary, at Pescadores Beach, where BT contamination was previously detected. Three replicate samples of surface sediment were collected randomly in each combination of period of the day, tidal zone, and tide condition, from three subareas along the beach, totaling 72 samples. BTs were analyzed by GC-PFPD using a tin filter and a VF-5 column, by means of a validated method. The concentrations of tributyltin (TBT), dibutyltin (DBT), and monobutyltin (MBT) ranged from undetectable to 161 ng Sn g -1 (d.w.). In most samples (71%), only MBT was quantifiable, whereas TBTs were measured in only 14, suggesting either an old contamination or rapid degradation processes. DBT was found in 27 samples, but could be quantified in only one. MBT concentrations did not differ significantly with time of day, zones, or tide conditions. DBT and TBT could not be compared under all these environmental conditions, because only a few samples were above the quantification limit. Pooled samples of TBT did not reveal any difference between day and night. These results indicated that, in assessing contamination by butyltin compounds, surface-sediment samples can be collected in any environmental conditions. However, the wide variation of BTs concentrations in the study area, i.e., over a very small

  12. Application of multivariate techniques in the optimization of a procedure for the determination of bioavailable concentrations of Se and As in estuarine sediments by ICP OES using a concomitant metals analyzer as a hydride generator.

    Science.gov (United States)

    Lopes, Watson da Luz; Santelli, Ricardo Erthal; Oliveira, Eliane Padua; de Carvalho, Maria de Fátima Batista; Bezerra, Marcos Almeida

    2009-10-15

    A procedure has been developed for the determination of bioavailable concentrations of selenium and arsenic in estuarine sediments employing inductively coupled plasma optical emission spectrometry (ICP OES) using a concomitant metals analyzer device to perform hydride generation. The optimization of hydride generation was done in two steps: using a two-level factorial design for preliminary evaluation of studied factors and a Doehlert design to assess the optimal experimental conditions for analysis. Interferences of transition metallic ions (Cd(2+), Co(2+), Cu(2+), Fe(3+) and Ni(2+)) to selenium and arsenic signals were minimized by using higher hydrochloric acid concentrations. In this way, the procedure allowed the determination of selenium and arsenic in sediments with a detection limit of 25 and 30 microg kg(-1), respectively, assuming a 50-fold sample dilution (0.5 g sample extraction to 25 mL sample final volume). The precision, expressed as a relative standard deviation (% RSD, n=10), was 0.2% for both selenium and arsenic in 200 microg L(-1) solutions, which corresponds to 10 microg g(-1) in sediment samples after acid extraction. Applying the proposed procedure, a linear range of 0.08-10 and 0.10-10 microg g(-1) was obtained for selenium and arsenic, respectively. The developed procedure was validated by the analysis of two certified reference materials: industrial sludge (NIST 2782) and river sediment (NIST 8704). The results were in agreement with the certified values. The developed procedure was applied to evaluate the bioavailability of both elements in four sediment certified reference materials, in which there are not certified values for bioavailable fractions, and also in estuarine sediment samples collected in several sites of Guanabara Bay, an impacted environment in Rio de Janeiro, Brazil.

  13. A microcosm approach to evaluate the degradation of tributyltin (TBT) by Aeromonas molluscorum Av27 in estuarine sediments.

    Science.gov (United States)

    Cruz, Andreia; Henriques, Isabel; Sousa, Ana C A; Baptista, Inês; Almeida, Adelaide; Takahashi, Shin; Tanabe, Shinsuke; Correia, António; Suzuki, Satoru; Anselmo, Ana Maria; Mendo, Sónia

    2014-07-01

    Tributyltin (TBT) is a biocide extremely toxic to a wide range of organisms, which has been used for decades in antifouling paints. Despite its global ban in 2008, TBT is still a problem of great concern due to the high levels trapped in sediments. Aeromonas molluscorum Av27 is a TBT degrading bacterium that was isolated from an estuarine system. We investigated the ability and the role of this bacterium on TBT degradation in this estuarine system, using a microcosm approach in order to mimic environmental conditions. The experiment was established and followed for 150 days. Simultaneously, changes in the indigenous bacterial community structure were also investigated. The results revealed a maximum TBT degradation rate of 28% accompanied by the detection of the degradation products over time. Additionally, it was observed that TBT degradation was significantly enhanced by the presence of Av27. In addition a significantly higher TBT degradation occurred when the concentration of Av27 was higher. TBT degradation affected the bacterial community composition as revealed by the changes in the prevalence of Proteobacteria subdivisions, namely the increase of Deltaproteobacteria and the onset of Epsilonproteobacteria. However, the addition of Av27 strain did not affect the dominant phylotypes. Total bacterial number, bacterial biomass productivity, 16S rRNA gene and denaturing gradient gel electrophoresis (DGGE) analyses also indicated alterations on the bacterial community structure over time, with bacteria non-tolerant to pollutants increasing their representativeness, as, for instance, the increase of the number of Alphaproteobacteria clones from 6% in the beginning to 12% at the end of the experiment. The work herein presented confirms the potential of Av27 strain to be used in the decontamination of TBT-polluted environments. Copyright © 2014 Elsevier Inc. All rights reserved.

  14. Plutonium in intertidal coastal and estuarine sediments in the Northern Irish Sea

    International Nuclear Information System (INIS)

    Aston, S.R.; Assinder, D.J.; Kelly, M.

    1985-01-01

    Surface intertidal sediments from 35 sites in the Irish Sea have been analysed for their 238 Pu and sup(239,240)Pu activities, together with an intensive study of plutonium in sediments of the Esk Estuary (NW England). The range of plutonium activities for the whole survey were 0.14-4118 and 1.3-16 026 Bq kg -1 for 238 Pu and sup(239,240)Pu, respectively. The levels of Pu activity, derived from the Sellafield nuclear fuel reprocessing effluents, in sediments are controlled by lithological factors and the influence of transport and post-depositional processes. Grain size distribution is particularly important, the major part of plutonium activity being in the mud fraction of all sediments. The data suggest that over the Irish Sea coastline, dynamic mixing of sediment grains by reworking and resuspension and/or by dispersion in tidal currents are important in determining plutonium distributions. The exponential decrease in sediment plutonium activities away from the Sellafield source is attributed to the progressive mixing with older contaminated and uncontaminated sediments. (author)

  15. Speciation of Co, Ni and Cu in the coastal and estuarine sediments: Some fundamental characteristics

    Digital Repository Service at National Institute of Oceanography (India)

    Chakraborty, P.

    provided a chemically significant description of the kinetics of metals–sediment interactions and correctly predicted the influences of ligand field stabilization energy (LFSE) and water exchange rate (k sub(-w)) on the dissociation rate constants of metals...

  16. Geochemical fractionation of 210Pb in oxic estuarine sediments of Coatzacoalcos River, Gulf of Mexico

    International Nuclear Information System (INIS)

    Ontiveros-Cuadras, J.F.; Ruiz-Fernandez, A.C.; Perez-Bernal, L.H.; Sanchez-Cabeza, J.A.; Universitat Autonoma de Barcelona; Wee-Kwong, L.L.

    2012-01-01

    210 Pb activities were analyzed in surface sediments from the Coatzacoalcos River (Gulf of Mexico) to evaluate its distribution according to sediment grain size and in different geochemical compartments by using sequential extraction techniques. The geochemical fractionation experiments provided compatible results: by using the Tessier's method more than 90% of the 210 Pb activity in the samples was found the residual fraction (primary and secondary minerals) and the remaining ( 210 Pb content was found in comparative amounts in the reactive, the silicate, and the pyrite fractions (accounting together for >80%), and the rest was found in the residual fraction. The grain size fractionation analyses showed that the 210 Pb activities were mostly retained in the clay fraction, accounting up to 60-70% of the 210 Pb total activity in the sediment sample and therefore, it is concluded that the separation of the clay fraction can be useful to improve the analysis of low 210 Pb content sediments for dating purposes. (author)

  17. The Effects of Varying Salinity on Ammonium Exchange in Estuarine Sediments of the Parker River, Massachusetts

    DEFF Research Database (Denmark)

    Weston, Nathaniel B.; Giblin, Anne E; Banta, Gary Thomas

    2010-01-01

    We examined the effects of seasonal salinity changes on sediment ammonium (NH4+) adsorption and exchange across the sediment–water interface in the Parker River Estuary, by means of seasonal field sampling, laboratory adsorption experiments, and modeling. The fraction of dissolvedNH4+relative...... to adsorbedNH4+in oligohaline sediments rose significantly with increased pore water salinity over the season. Laboratory experiments demonstrated that small (∼3) increases in salinity from freshwater conditions had the greatest effect onNH4+adsorption by reducing the exchangeable pool from 69% to 14......% of the totalNH4+in the upper estuary sediments that experience large (0–20) seasonal salinity shifts.NH4+dynamics did not appear to be significantly affected bysalinity in sediments of the lower estuary where salinities under 10 were not measured. We further assessed the importance of salinity...

  18. Estuarine Suspended Sediment Dynamics: Observations Derived from over a Decade of Satellite Data

    Directory of Open Access Journals (Sweden)

    Anthony Reisinger

    2017-12-01

    Full Text Available Suspended sediment dynamics of Corpus Christi Bay, Texas, USA, a shallow-water wind-driven estuary, were investigated by combining field and satellite measurements of total suspended solids (TSS. An algorithm was developed to transform 500-m Moderate Resolution Imaging Spectroradiometer (MODIS Aqua satellite reflectance data into estimated TSS values. The algorithm was developed using a reflectance ratio regression of MODIS Band 1 (red and Band 3 (green with TSS measurements (n = 54 collected by the Texas Commission on Environmental Quality for Corpus Christi Bay and other Texas estuaries. The algorithm was validated by independently collected TSS measurements during the period of 2011–2014 with an uncertainty estimate of 13%. The algorithm was applied to the period of 2002–2014 to create a synoptic time series of TSS for Corpus Christi Bay. Potential drivers of long-term variability in suspended sediment were investigated. Median and IQR composites of suspended sediments were generated for seasonal wind regimes. From this analysis it was determined that long-term, spatial patterns of suspended sediment in the estuary are related to wind-wave resuspension during the predominant northerly and prevalent southeasterly seasonal wind regimes. The impact of dredging is also apparent in long-term patterns of Corpus Christi Bay as concentrations of suspended sediments over dredge spoil disposal sites are higher and more variable than surrounding areas, which is most likely due to their less consolidated sediments and shallower depths requiring less wave energy for sediment resuspension. This study highlights the advantage of how long-synoptic time series of TSS can be used to elucidate the major drivers of suspended sediments in estuaries.

  19. Sediment quality guidelines for copper and zinc for filter-feeding estuarine oysters?

    Energy Technology Data Exchange (ETDEWEB)

    Birch, G.F., E-mail: gavin.birch@sydney.edu.a [Environmental Geology Group, School of Geosciences, Sydney University, NSW (Australia); Hogg, T.D. [Environmental Geology Group, School of Geosciences, Sydney University, NSW (Australia)

    2011-01-15

    Sediment quality guidelines (SQGs) assess the ability of bottom sediment to sustain healthy infauna and water quality guidelines (WQGs) provide protection for a designated percentage of aquatic species. Filter-feeding marine species, e.g. oysters and mussels, acquire food from particles in the water column and protection of these animals is not provided by SQGs or WQGs. The current work investigated the relationship between metal (Cu, Zn) concentrations in total and fine-fraction (<62.5 {mu}m) surficial sediment digested in a range of acids and chelating agents and oyster tissue metal concentrations. A strong correlation between oyster tissue Cu and Zn concentrations and fine-fraction surficial sediment digested in 1 M HCl provided a sedimentary guideline which predicted tissue metal concentrations in oysters and established a level (<45 {mu}g g{sup -1} and <1000 {mu}g g{sup -1}, respectively) for protecting oysters from exceeding human consumption levels (70 {mu}g g{sup -1} and 1000 {mu}g g{sup -1}, respectively). - A strong correlation between oyster tissue Cu and Zn concentrations and fine-fraction surficial sediment digested in 1 M HCl provided a sedimentary guideline which predicted tissue metal concentrations in oysters and established a level for protecting oysters from exceeding human consumption levels for these metals. The guidelines for fine surficial sediment developed in the present work accurately predicted oyster tissue concentrations in the field.

  20. Estuarine Sediment Deposition during Wetland Restoration: A GIS and Remote Sensing Modeling Approach

    Science.gov (United States)

    Newcomer, Michelle; Kuss, Amber; Kentron, Tyler; Remar, Alex; Choksi, Vivek; Skiles, J. W.

    2011-01-01

    Restoration of the industrial salt flats in the San Francisco Bay, California is an ongoing wetland rehabilitation project. Remote sensing maps of suspended sediment concentration, and other GIS predictor variables were used to model sediment deposition within these recently restored ponds. Suspended sediment concentrations were calibrated to reflectance values from Landsat TM 5 and ASTER using three statistical techniques -- linear regression, multivariate regression, and an Artificial Neural Network (ANN), to map suspended sediment concentrations. Multivariate and ANN regressions using ASTER proved to be the most accurate methods, yielding r2 values of 0.88 and 0.87, respectively. Predictor variables such as sediment grain size and tidal frequency were used in the Marsh Sedimentation (MARSED) model for predicting deposition rates for three years. MARSED results for a fully restored pond show a root mean square deviation (RMSD) of 66.8 mm (<1) between modeled and field observations. This model was further applied to a pond breached in November 2010 and indicated that the recently breached pond will reach equilibrium levels after 60 months of tidal inundation.

  1. The combined use of the PLHC-1 cell line and the recombinant yeast assay to assess the environmental quality of estuarine and coastal sediments.

    Science.gov (United States)

    Schnell, Sabine; Olivares, Alba; Piña, Benjamin; Echavarri-Erasun, Beatriz; Lacorte, Silvia; Porte, Cinta

    2013-12-15

    Sediment contamination poses a potential risk for both ecosystems and human health. Risk assessment is troublesome as sediments contain complex mixtures of toxicants, and traditional chemical analyses can neither provide information about potential hazards to organisms nor identify and measure all present contaminants. This work combines the use of the PLHC-1 cell line and the recombinant yeast assay (RYA) to assess the environmental quality of estuarine and coastal sediments. The application of multiple endpoints (cytotoxicity, generation of oxidative stress, presence of CYP1A inducing agents, micronucleus formation and estrogenicity) revealed that the organic extracts of those sediments affected by industrial activities or collected near harbours and untreated urban discharges showed significant cytotoxicity, micronuclei and CYP1A induction. The study highlights the usefulness of the applied bioassays to identify those sediments that could pose risk to aquatic organisms and that require further action to improve their environmental quality. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Impact of estuarine gradients on reductive dechlorination of 1,2,3,4-tetrachlorodibenzo-p-dioxin in river sediment enrichment cultures.

    Science.gov (United States)

    Dam, Hang T; Häggblom, Max M

    2017-02-01

    Polychlorinated dibenzo-p-dioxins (PCDDs) are among the most persistent organic pollutants. Although the total input of PCDDs into the environment has decreased substantially over the past four decades, their input via non-point sources is still increasing, especially in estuarine metropolitan areas. Here we report on the microbially mediated reductive dechlorination of PCDDs in anaerobic enrichment cultures established from sediments collected from five locations along the Hackensack River, NJ and investigate the impacts of sediment physicochemical characteristics on dechlorination activity. Dechlorination of 1,2,3,4-tetrachlorodibenzo-p-dioxin (1,2,3,4-TeCDD) and abundance of Dehalococcoides spp. negatively correlated with salinity and sulfate concentration in sediments used to establish the cultures. 1,2,3,4-TeCDD was dechlorinated to a lesser extent in cultures established from sediments from the tidally influenced estuarine mouth of the river. In cultures established from low salinity sediments, 1,2,3,4-TeCDD was reductively dechlorinated with the accumulation of 2-monochlorodibenzo-p-dioxin as the major product. Sulfate concentrations above 2 mM inhibited 1,2,3,4-TecDD dechlorination activity. Consecutive lateral- and peri- dechlorination took place in enrichment cultures with a minimal accumulation of 2,3-dichlorodibenzo-p-dioxin in active cultures. A Dehalococcoides spp. community was enriched and accounted for up to 64% of Chloroflexi detected in these sediment cultures. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Lipid and DNA biomarker analyses of Narragansett Bay Sediments: Evaluating the UK'37 proxy in an Estuarine Environment

    Science.gov (United States)

    George, S. E.; Herbert, T.; Amaral-Zettler, L. A.; Richter, N.

    2017-12-01

    Long chain polyunsaturated alkenone (LCA) lipid biomarkers produced by haptophyte phytoplankton species within the Order Isochrysidales (Phylum Haptophyta) have proven exceptionally useful in paleotemperature studies by means of the Uk'37 and Uk37 indices. Two closely-related Group III haptophytes, Emiliania huxleyi and Gephyrocapsa oceanica are the primary alkenone synthesizers in the modern ocean, while freshwater systems host the distinct Group I phylotype, sometimes called the Greenland phylotype, in reference to the location of its original discovery. Group I haptophytes produce large quantities of the distinct C37:4 ketone, which acts as a chemical `fingerprint' in sediments. The utility of alkenones as a paleotemperature proxy in estuarine environments has remained largely untested, representing an under-utilized opportunity to construct high-resolution paleotemperature records from environments at the intersection of fluvial and marine systems. This uncertainty is due, in part, to the presence of multiple haptophyte groups in estuaries, resulting in a mixed alkenone signature. To determine the community composition of alkenone-producing haptophytes within Narragansett Bay, four geographically separated cores from within the Bay were analyzed for alkenones as well as haptophyte rRNA biomarker gene presence. Haptophyte rRNA genes (small and large subunit) were recovered from surface and near-subsurface samples, and in conjunction with alkenone profiles, reveal recent haptophyte community structure and alkenone production regimes throughout the Bay. A surprising result is the recovery of rRNA biomarker genes with a 100% match to the open-ocean alkenone producer E. huxleyi in locations away from large fresh water inputs to the Bay. Results of these analyses elucidate the effect of salinity and nutrient dynamics on alkenone-producing haptophyte communities and enhance applicability of long chain polyunsaturated alkenones as lipid biomarkers in estuarine

  4. Suspended-sediment trapping in the tidal reach of an estuarine tributary channel

    Science.gov (United States)

    Downing-Kunz, Maureen; Schoellhamer, David H.

    2015-01-01

    Evidence of decreasing sediment supply to estuaries and coastal oceans worldwide illustrates the need for accurate and updated estimates. In the San Francisco Estuary (Estuary), recent research suggests a decrease in supply from its largest tributaries, implying the increasing role of smaller, local tributaries in sediment supply to this estuary. Common techniques for estimating supply from tributaries are based on gages located above head of tide, which do not account for trapping processes within the tidal reach. We investigated the effect of a tidal reach on suspended-sediment discharge for Corte Madera Creek, a small tributary of the Estuary. Discharge of water (Q) and suspended-sediment (SSD) were observed for 3 years at two locations along the creek: upstream of tidal influence and at the mouth. Comparison of upstream and mouth gages showed nearly 50 % trapping of upstream SSD input within the tidal reach over this period. At the storm time scale, suspended-sediment trapping efficiency varied greatly (range −31 to 93 %); storms were classified as low- or high-yield based on upstream SSD. As upstream peak Q increased, high-yield storms exhibited significantly decreased trapping. Tidal conditions at the mouth—ebb duration and peak ebb velocity—during storms had a minor effect on sediment trapping, suggesting fluvial processes dominate. Comparison of characteristic fluvial and tidal discharges at the storm time scale demonstrated longitudinal differences in the regulating process for SSD. These results suggest that SSD from gages situated above head of tide overestimate sediment supply to the open waters beyond tributary mouths and thus trapping processes within the tidal reach should be considered.

  5. Links between contaminant hotspots in low flow estuarine systems and altered sediment biogeochemical processes

    Science.gov (United States)

    Sutherland, Michael D.; Dafforn, Katherine A.; Scanes, Peter; Potts, Jaimie; Simpson, Stuart L.; Sim, Vivian X. Y.; Johnston, Emma L.

    2017-11-01

    The urbanisation of coastal zones is a major threat to the health of global estuaries and has been linked to increased contamination (e.g. metals) and excess organic matter. Urban stormwater networks collect and funnel contaminants into waterways at point sources (e.g. stormdrains). Under dry, low flow conditions, these stormwater contaminants can accumulate in sediments over time and result in modifications to benthic sediment biogeochemical processes. To quantify these processes, this field study measured differences in benthic metabolism (CR, GPP, NEM) and sediment-water nutrient fluxes (NH3, NOx, PO4) associated with stormdrains (0 m, 200 m and 1000 m away) and increased water-retention (embayments vs channels). Significant changes to benthic metabolism were detected with distance from stormdrains, and with differences in water-retention rates, above natural spatial and temporal variation. Oxygen consumption was ∼50% higher at stormdrains (0 m) compared to 1000 m away and >70% higher at stormdrains (0 m) located in embayments compared to channels. Oxygen production also appeared to decrease with distance from stormdrains in embayments, but patterns were variable. These changes to benthic metabolism were of a magnitude expected to influence benthic nutrient cycling, but NH3, NOx and PO4 fluxes were generally low, and highly spatially and temporally variable. Overall, metal (Cu) contamination explained most of the variation in sediment biogeochemical processes between embayments and channels, while sediment grain size explained differences in fluxes with distance from stormdrains. Importantly, although there was evidence of increased productivity associated with stormdrains, we also detected evidence of early hypoxia suggesting that systems with legacy stormwater contaminants exist on a tipping point. Future work should investigate changes to sediment processes after a major rainfall event, when large and sudden inputs of potentially toxic contaminants occur

  6. Iron ore pollution in Mandovi and Zuari estuarine sediments and its fate after mining ban

    Digital Repository Service at National Institute of Oceanography (India)

    Kessarkar, P.M.; Suja, S.; Sudheesh, V.; Srivastava, S.; Rao, V.P.

    ). Another possibility could be formation of ferritized iron crust (Mathe et al. 1997) during lateritic weathering. Magnetic properties of upstream sediments of Ma-Zu estuaries Sediments from the upstream of Mandovi (M6-M9) and Zuari (Z6-Z9) estuaries... for late Quaternary climatic change. Marine Geology, 220, 59-82. Maher, B. A., & Taylor, R. M. (1988). Formation of ultrafine-grained magnetite in soils. Nature, 336, 368-370. Mathe, P. E., Rochette, P., & Colin, F. (1997). The origin of magnetic...

  7. Distribution of radionuclides in the sediments of Cananeia-Iguape Estuarine Complex (SP, Brazil)

    International Nuclear Information System (INIS)

    Ribeiro, Andreza P.; Ferreira, Paulo A.L.; Mahiques, Michel M.

    2013-01-01

    With the advent of techniques that enabled the detection of radioactivity, a new frontier was opened in the many areas of Earth sciences, as the radionuclides can be used as tracers for processes of physical, chemical and biological natures. In this context, natural ( 40 K, 232 Th and 238 U) and artificial ( 137 Cs) radionuclides were measured through the means of high-resolution gamma spectrometry, a non-destructive technique, in the Cananeia-Iguape Estuarine Complex (Sao Paulo, Brazil). The activities obtained are 107.61 - 573.84 Bq kg -1 for 40 K, 11.11 - 73.65 Bq kg -1 for 232 Th, 2.27 - 60.76 Bq kg -1 for 238 U, and 0.23 - 3.49 Bq kg -1 for 137 Cs, with 137 Cs content within the observed range for samples environmentally affected only by the fallout of past nuclear tests. Also, these radionuclides presented a significant (α = 0.05) correlation with grain size distribution and organic carbon content as well. (author)

  8. Sediment diatom species and community response to nitrogen addition in Oregon (USA) estuarine tidal wetlands

    Science.gov (United States)

    Sediment microalgae play an important role in nutrient cycling and are important primary producers in the food web in Pacific Northwest estuaries. This study examines the effects of nitrogen addition to benthic microalgae in tidal wetlands of Yaquina Bay estuary on the Oregon c...

  9. Sediment quality guidelines for copper and zinc for filter-feeding estuarine oysters?

    International Nuclear Information System (INIS)

    Birch, G.F.; Hogg, T.D.

    2011-01-01

    Sediment quality guidelines (SQGs) assess the ability of bottom sediment to sustain healthy infauna and water quality guidelines (WQGs) provide protection for a designated percentage of aquatic species. Filter-feeding marine species, e.g. oysters and mussels, acquire food from particles in the water column and protection of these animals is not provided by SQGs or WQGs. The current work investigated the relationship between metal (Cu, Zn) concentrations in total and fine-fraction ( -1 and -1 , respectively) for protecting oysters from exceeding human consumption levels (70 μg g -1 and 1000 μg g -1 , respectively). - A strong correlation between oyster tissue Cu and Zn concentrations and fine-fraction surficial sediment digested in 1 M HCl provided a sedimentary guideline which predicted tissue metal concentrations in oysters and established a level for protecting oysters from exceeding human consumption levels for these metals. The guidelines for fine surficial sediment developed in the present work accurately predicted oyster tissue concentrations in the field.

  10. An in situ postexposure feeding assay with Carcinus maenas for estuarine sediment-overlying water toxicity evaluations

    International Nuclear Information System (INIS)

    Moreira, Susana M.; Moreira-Santos, Matilde; Guilhermino, Lucia; Ribeiro, Rui

    2006-01-01

    This study developed and evaluated a short-term sublethal in situ toxicity assay for estuarine sediment-overlying waters, with the crab Carcinus maenas (L.) based on postexposure feeding. It consisted of a 48-h in situ exposure period followed by a short postexposure feeding period (30 min). A precise method for quantifying feeding, using the Polychaeta Hediste (Nereis) diversicolor Mueller as food source, was first developed. The sensitivity of the postexposure feeding response was verified by comparing it to that of lethality, upon cadmium exposure. The influence of environmental conditions prevailing during exposure (salinity, temperature, substrate, light regime, and food availability) on postexposure feeding was also addressed. The potential of this in situ assay was then investigated by deploying organisms at ten sites, located in reference and contaminated Portuguese estuaries. Organism recovery ranged between 90% and 100% and a significant postexposure feeding depression (16.3-72.7%) was observed at all contaminated sites relatively to references. - A new sub-lethal toxicity assay is presented for marine invertebrates

  11. Co-existence of Methanogenesis and Sulfate Reduction with Common Substrates in Sulfate-Rich Estuarine Sediments

    Directory of Open Access Journals (Sweden)

    Michal Sela-Adler

    2017-05-01

    Full Text Available The competition between sulfate reducing bacteria and methanogens over common substrates has been proposed as a critical control for methane production. In this study, we examined the co-existence of methanogenesis and sulfate reduction with shared substrates over a large range of sulfate concentrations and rates of sulfate reduction in estuarine systems, where these processes are the key terminal sink for organic carbon. Incubation experiments were carried out with sediment samples from the sulfate-methane transition zone of the Yarqon (Israel estuary with different substrates and inhibitors along a sulfate concentrations gradient from 1 to 10 mM. The results show that methanogenesis and sulfate reduction can co-exist while the microbes share substrates over the tested range of sulfate concentrations and at sulfate reduction rates up to 680 μmol L-1 day-1. Rates of methanogenesis were two orders of magnitude lower than rates of sulfate reduction in incubations with acetate and lactate, suggesting a higher affinity of sulfate reducing bacteria for the available substrates. The co-existence of both processes was also confirmed by the isotopic signatures of δ34S in the residual sulfate and that of δ13C of methane and dissolved inorganic carbon. Copy numbers of dsrA and mcrA genes supported the dominance of sulfate reduction over methanogenesis, while showing also the ability of methanogens to grow under high sulfate concentration and in the presence of active sulfate reduction.

  12. Assessing the potential ecological risk of Co, Cr, Cu, Fe and Zn in the sediments of Hooghly-Matla estuarine system, India.

    Science.gov (United States)

    Ghosh, Somdeep; Bakshi, Madhurima; Kumar, Alok; Ramanathan, A L; Biswas, Jayanta Kumar; Bhattacharyya, Subarna; Chaudhuri, Punarbasu; Shaheen, Sabry M; Rinklebe, Jörg

    2018-05-09

    Hooghly-Matla estuarine system along with the Sundarbans mangroves forms one of the most diverse and vulnerable ecosystems in the world. We have investigated the distribution of Co, Cr, Cu, Fe and Zn along with sediment properties at six locations [Shamshernagar (S1), Kumirmari (S2 and S3), Petuaghat (S4), Tapoban (S5) and Chemaguri (S6)] in the Hooghly estuary and reclaimed islands of the Sundarbans for assessing the degree of contamination and potential ecological risks. Enrichment factor values (0.9-21.6) show enrichment of Co, Cu and Zn in the intertidal sediments considering all sampling locations and depth profiles. Geo-accumulation index values irrespective of sampling locations and depth revealed that Co and Cu are under class II and class III level indicating a moderate contamination of sediments. The pollution load index was higher than unity (1.6-2.1), and Co and Cu were the major contributors to the sediment pollution followed by Zn, Cr and Fe with the minimum values at S1 and the maximum values at S5. The sediments of the Hooghly-Matla estuarine region (S4, S5 and S6) showed considerable ecological risks, when compared with effect range low/effect range median and threshold effect level/probable effect level values. The variation in the distribution of the studied elements may be due to variation in discharge pattern and exposure to industrial effluent and domestic sewage, storm water and agricultural run-off and fluvial dynamics of the region. The study illuminates the necessity for the proper management of vulnerable coastal estuarine ecosystem by stringent pollution control measures along with regular monitoring and checking program.

  13. The Effects of Salinity on Nitrogen Losses from an Oligohaline Estuarine Sediment

    DEFF Research Database (Denmark)

    Giblin, Anne E.; Weston, Nathaniel B.; Banta, Gary Thomas

    2010-01-01

    Benthic respiration, sediment–water nutrient fluxes, denitrification and dissimilatory nitrate reduction to ammonium (DNRA) were measured in the upper section of the Parker River Estuary from 1993 to 2006. This site experiences large changes in salinity over both short and long time scales....... Sediment respiration ranged from 6 to 52 mmol m−2 day−1 and was largely controlled by temperature. Nutrient fluxes were dominated by ammonium fluxes, which ranged from a small uptake of −0.3 to an efflux of over 8.2 mmol N m−2 day−1. Ammonium fluxes were most highly correlated with salinity and laboratory...... related to salinity, ranging from 1 mmol m−2 day−1 during the spring and fall to less than 0.2 mmol m−2 day−1 in late summer. Salinity appears to exert a major control on the nitrogen cycle at this site, and partially decouples sediment ammonium fluxes from organic matter decomposition....

  14. Seagrass sediments reveal the long-term deterioration of an estuarine ecosystem.

    Science.gov (United States)

    Serrano, Oscar; Lavery, Paul; Masque, Pere; Inostroza, Karina; Bongiovanni, James; Duarte, Carlos

    2016-04-01

    The study of a Posidonia australis sediment archive has provided a record of ecosystem dynamics and processes over the last 600 years in Oyster Harbour (SW Australia). Ecosystem shifts are a widespread phenomenon in coastal areas, and this study identifies baseline conditions and the time-course of ecological change (cycles, trends, resilience and thresholds of ecosystem change) under environmental stress in seagrass-dominated ecosystem. The shifts in the concentrations of chemical elements, carbonates, sediments ecosystem and the associated regime shifts, which can be used to improve the capacity of scientists and environmental managers to understand, predict and better manage ecological change in these ecosystems. © 2016 John Wiley & Sons Ltd.

  15. Adsorption-Desorption Characteristics of Plutonium and Americium with Sediment Particles in the Estuarine Environment

    International Nuclear Information System (INIS)

    Murray, C.N.; Fukai, R.

    1976-01-01

    The particle formation of plutonium and americium, their adsorption onto fresh water sediments and the desorption from the sediments in sea water were studied in the Laboratory under simulated river-estuary conditions, using γ-emitting plutonium-237 and americium-241. The results of the experiments show that the particle formation of plutonium depends on its valence states, on pH and on the salinity of the medium. For river water at pH4, some 25%, 20% and 30% of the added 237 Pu was in particulate form, larger than 0.45pm, for Pu (III), Pu (IV) and Pu (VI), respectively, while 65%, 90% and 50% of the respective valence states was associated with particles at pH 8. In sea water the general pattern remains similar, although Pu (VI) is more soluble in sea water owing to higher ligand concentrations for carbonate and bicarbonate complexes. The pH-dependency of particle formation of Am (III) is more steep than that of plutonium and seems to be influenced by colloidal substances occurring in the experimental media. The adsorption-desorption characteristics of plutonium and americium with the sediment in river water as well as sea water reflect the characteristics of their particle formation, being dependent upon such properties as valence states, the pH and salinity of the medium. A sewage effluent added to the media has small but measurable effects on the adsorption-desorption processes of plutonium. (author)

  16. Nitrogen reduction pathways in estuarine sediments: Influences of organic carbon and sulfide

    Science.gov (United States)

    Plummer, Patrick; Tobias, Craig; Cady, David

    2015-10-01

    Potential rates of sediment denitrification, anaerobic ammonium oxidation (anammox), and dissimilatory nitrate reduction to ammonium (DNRA) were mapped across the entire Niantic River Estuary, CT, USA, at 100-200 m scale resolution consisting of 60 stations. On the estuary scale, denitrification accounted for ~ 90% of the nitrogen reduction, followed by DNRA and anammox. However, the relative importance of these reactions to each other was not evenly distributed through the estuary. A Nitrogen Retention Index (NIRI) was calculated from the rate data (DNRA/(denitrification + anammox)) as a metric to assess the relative amounts of reactive nitrogen being recycled versus retained in the sediments following reduction. The distribution of rates and accompanying sediment geochemical analytes suggested variable controls on specific reactions, and on the NIRI, depending on position in the estuary and that these controls were linked to organic carbon abundance, organic carbon source, and pore water sulfide concentration. The relationship between NIRI and organic carbon abundance was dependent on organic carbon source. Sulfide proved the single best predictor of NIRI, accounting for 44% of its observed variance throughout the whole estuary. We suggest that as a single metric, sulfide may have utility as a proxy for gauging the distribution of denitrification, anammox, and DNRA.

  17. Sediment Sampling in Estuarine Mudflats with an Aerial-Ground Robotic Team

    Directory of Open Access Journals (Sweden)

    Pedro Deusdado

    2016-09-01

    Full Text Available This paper presents a robotic team suited for bottom sediment sampling and retrieval in mudflats, targeting environmental monitoring tasks. The robotic team encompasses a four-wheel-steering ground vehicle, equipped with a drilling tool designed to be able to retain wet soil, and a multi-rotor aerial vehicle for dynamic aerial imagery acquisition. On-demand aerial imagery, properly fused on an aerial mosaic, is used by remote human operators for specifying the robotic mission and supervising its execution. This is crucial for the success of an environmental monitoring study, as often it depends on human expertise to ensure the statistical significance and accuracy of the sampling procedures. Although the literature is rich on environmental monitoring sampling procedures, in mudflats, there is a gap as regards including robotic elements. This paper closes this gap by also proposing a preliminary experimental protocol tailored to exploit the capabilities offered by the robotic system. Field trials in the south bank of the river Tagus’ estuary show the ability of the robotic system to successfully extract and transport bottom sediment samples for offline analysis. The results also show the efficiency of the extraction and the benefits when compared to (conventional human-based sampling.

  18. Sediment Sampling in Estuarine Mudflats with an Aerial-Ground Robotic Team

    Science.gov (United States)

    Deusdado, Pedro; Guedes, Magno; Silva, André; Marques, Francisco; Pinto, Eduardo; Rodrigues, Paulo; Lourenço, André; Mendonça, Ricardo; Santana, Pedro; Corisco, José; Almeida, Susana Marta; Portugal, Luís; Caldeira, Raquel; Barata, José; Flores, Luis

    2016-01-01

    This paper presents a robotic team suited for bottom sediment sampling and retrieval in mudflats, targeting environmental monitoring tasks. The robotic team encompasses a four-wheel-steering ground vehicle, equipped with a drilling tool designed to be able to retain wet soil, and a multi-rotor aerial vehicle for dynamic aerial imagery acquisition. On-demand aerial imagery, properly fused on an aerial mosaic, is used by remote human operators for specifying the robotic mission and supervising its execution. This is crucial for the success of an environmental monitoring study, as often it depends on human expertise to ensure the statistical significance and accuracy of the sampling procedures. Although the literature is rich on environmental monitoring sampling procedures, in mudflats, there is a gap as regards including robotic elements. This paper closes this gap by also proposing a preliminary experimental protocol tailored to exploit the capabilities offered by the robotic system. Field trials in the south bank of the river Tagus’ estuary show the ability of the robotic system to successfully extract and transport bottom sediment samples for offline analysis. The results also show the efficiency of the extraction and the benefits when compared to (conventional) human-based sampling. PMID:27618060

  19. Effects of Cohesive Sediment on Estuarine Morphology in Laboratory Scale Experiments

    Science.gov (United States)

    Braat, L.; Leuven, J.; Lokhorst, I.; Kleinhans, M. G.

    2017-12-01

    Mud plays a major role in forming and filling of river estuaries. River estuaries are typically build of sand and flanked by mudflats, which affect channel-shoal dynamics on time scales of centuries to millennia. In our research we aim to study the effects of mud on the shape and evolution of estuaries and where the largest effects occur. Recently a 20 m by 3 m flume (the Metronome) was developed at Utrecht University for tidal experiments. Complete estuaries are simulated in the Metronome by driving tidal flow by periodically tilting of the flume to counteract scaling problems. To simulate the effects of cohesive mud we supply nutshell grains to the system together with the river discharge. Three scenarios were tested, one with only sand, one with a low supply concentration of nutshell and one with a high concentration (left to right in figure).Estuaries that developed from an initial convergent shape are self-formed through bank erosion, continuous channel-shoal migration and bar and mud flat sedimentation (figure shows development over 15000 tilting cycles). The cohesive sediment deposits occur mainly on bars, but also on the flanks of the estuary and in abandoned channels. Due to its different erosional and depositional characteristics, the nutshell increases the elevation of the bars, which reduces storage and ebb-dominance and causes reduction of bar mobility and short cuts. These results agree with numerical model results. The large-scale effect is less widening of the estuary in the presence of mud and a decrease in channel-shoal migration, suggesting that mud confines estuary width in a similar manner as river floodplains.

  20. A Random Forest approach to predict the spatial distribution of sediment pollution in an estuarine system.

    Directory of Open Access Journals (Sweden)

    Eric S Walsh

    Full Text Available Modeling the magnitude and distribution of sediment-bound pollutants in estuaries is often limited by incomplete knowledge of the site and inadequate sample density. To address these modeling limitations, a decision-support tool framework was conceived that predicts sediment contamination from the sub-estuary to broader estuary extent. For this study, a Random Forest (RF model was implemented to predict the distribution of a model contaminant, triclosan (5-chloro-2-(2,4-dichlorophenoxyphenol (TCS, in Narragansett Bay, Rhode Island, USA. TCS is an unregulated contaminant used in many personal care products. The RF explanatory variables were associated with TCS transport and fate (proxies and direct and indirect environmental entry. The continuous RF TCS concentration predictions were discretized into three levels of contamination (low, medium, and high for three different quantile thresholds. The RF model explained 63% of the variance with a minimum number of variables. Total organic carbon (TOC (transport and fate proxy was a strong predictor of TCS contamination causing a mean squared error increase of 59% when compared to permutations of randomized values of TOC. Additionally, combined sewer overflow discharge (environmental entry and sand (transport and fate proxy were strong predictors. The discretization models identified a TCS area of greatest concern in the northern reach of Narragansett Bay (Providence River sub-estuary, which was validated with independent test samples. This decision-support tool performed well at the sub-estuary extent and provided the means to identify areas of concern and prioritize bay-wide sampling.

  1. Composition and Sources of Fatty Alcohols in Estuarine Sediments of Sungai Kapar, Selangor

    International Nuclear Information System (INIS)

    Norfariza Humrawali; Kwan, Y.L.; Mohd Talib Latif; Masni Mohd Ali; Mohamad Pauzi Zakaria

    2010-01-01

    A total of 13 fatty alcohols (C 12 - C 24 ) including six branched compounds have been identified in seven surface sediment samples taken from Sungai Kapar, Selangor using computerized gas chromatography-mass spectrometry (GC-MS). Generally 65 % of total fatty alcohols determined were short chain compounds (C 12 - C 20 ) derived from marine organisms, 14 % were long chained compounds (C 21 - C 24 ) input of terrestrial plants and the rest were branched compounds from bacterial activity. C 16 compound dominated all the sampling stations with concentrations ranged from 29.69 to 164.35 μgg -1 dry weight which constitute 32 % of total fatty alcohols. Short chain/long chain fatty alcohols ratio [Σ(C 12 - C 20 )/ Σ(C 21 - C 22 )] of each sampling stations had the value >1; indicating high content of short chain compounds from marine sources. Meanwhile, Alcohol Source Index (ASI) calculated using C 22 / C 14 and C 22 / C 16 ratios. C 22 / C 14 ratio showed that stations Kp1, Kp2, Kp5 and Kp6 had a value >1 indicating the amount of C 22 was higher than C 14 . Ratio of C 22 / C 16 showed that all the sampling stations dominated by C 16 compared to C 22 . The estuary of Sungai Kapar, Selangor was dominated by short chain fatty alcohols (C 12 - C 20 ) especially C 16 compound rather than long chain fatty alcohol (C 21 - C 24 ). (author)

  2. Spatial and temporal variability of contaminants within estuarine sediments and native Olympia oysters: A contrast between a developed and an undeveloped estuary

    Science.gov (United States)

    Granek, Elise F.; Conn, Kathleen E.; Nilsen, Elena B.; Pillsbury, Lori; Strecker, Angela L.; Rumrill, Steve; Fish, William

    2016-01-01

    Chemical contaminants can be introduced into estuarine and marine ecosystems from a variety of sources including wastewater, agriculture and forestry practices, point and non-point discharges, runoff from industrial, municipal, and urban lands, accidental spills, and atmospheric deposition. The diversity of potential sources contributes to the likelihood of contaminated marine waters and sediments and increases the probability of uptake by marine organisms. Despite widespread recognition of direct and indirect pathways for contaminant deposition and organismal exposure in coastal systems, spatial and temporal variability in contaminant composition, deposition, and uptake patterns are still poorly known. We investigated these patterns for a suite of persistent legacy contaminants including polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) and chemicals of emerging concern including pharmaceuticals within two Oregon coastal estuaries (Coos and Netarts Bays). In the more urbanized Coos Bay, native Olympia oyster (Ostrea lurida) tissue had approximately twice the number of PCB congeners at over seven times the total concentration, yet fewer PBDEs at one-tenth the concentration as compared to the more rural Netarts Bay. Different pharmaceutical suites were detected during each sampling season. Variability in contaminant types and concentrations across seasons and between species and media (organisms versus sediment) indicates the limitation of using indicator species and/or sampling annually to determine contaminant loads at a site or for specific species. The results indicate the prevalence of legacy contaminants and CECs in relatively undeveloped coastal environments highlighting the need to improve policy and management actions to reduce contaminant releases into estuarine and marine waters and to deal with legacy compounds that remain long after prohibition of use. Our results point to the need for better understanding of the ecological and

  3. Diversions of the Ribeira river flow and their Influence on Sediment Supply in the Cananeia-Iguape Estuarine-Lagoonal System (SE Brazil)

    Science.gov (United States)

    Cornaggia, Flaminia; Jovane, Luigi; Alessandretti, Luciano; Alves de Lima Ferreira, Paulo; Lopes Figueira, Rubens C.; Rodelli, Daniel; Bueno Benedetti Berbel, Gláucia; Braga, Elisabete S.

    2018-04-01

    The Cananéia-Iguape system is a combined estuarine-lagoonal sedimentary system, located along the SE coast of Brazil. It consists of a network of channels and islands oriented mainly parallel to the coast. About 165 years ago, an artificial channel, the Valo Grande, was opened in the northern part of this system to connect a major river of the region, the Ribeira River, to the estuarine-lagoon complex. The Valo Grande was closed with a dam and re-opened twice between 1978 and 1995, when it was finally left open. These openings and closures of the Valo Grande had a significant influence on the Cananéia-Iguape system. In this study we present mineralogical, chemical, palaeomagnetic, and geochronological data from a sediment core collected at the southern end of the 50-km long lagoonal system showing how the phases of the opening and closure of the channel through time are expressed in the sedimentary record. Despite the homogeneity of the grain size and magnetic properties throughout the core, significant variations in the mineralogical composition showed the influence of the opening of the channel on the sediment supply. Less mature sediment, with lower quartz and halite and higher kaolinite, brucite, and franklinite, corresponded to periods when the Valo Grande was open. On the other hand, higher abundance of quartz and halite, as well as the disappearance of other detrital minerals, corresponded with periods of absence or closure of the channel, indicating a more sea-influenced depositional setting. This work represented an example of anthropogenic influence in a lagoonal-estuarine sedimentary system, which is a common context along the coast of Brazil.

  4. A comparative study of neutron activation analysis and proton-induced X-ray emission analysis for the determination of heavy metals in estuarine sediments

    Science.gov (United States)

    Randle, K.; Al-Jundi, J.; Mamas, C. J. V.; Sokhi, R. S.; Earwaker, L. G.

    1993-06-01

    Our work on heavy metals in the estuarine environment has involved the use of two multielement techniques: neutron activation analysis (NAA) and proton-induced X-ray emission (PIXE) analysis. As PIXE is essentially a surface analytical technique problems may arise due to sample inhomogeneity and surface roughness. In order to assess the contribution of these effects we have compared the results from PIXE analysis with those from a technique which analyzes a larger bulk sample rather than just the surface. An obvious method was NAA. A series of sediment samples containing particles of variable diameter were compared. Pellets containing a few mg of sediment were prepared from each sample and analyzed by the PIXE technique using both an absolute and a comparitive method. For INAA the rest of the sample was then irradiated with thermal neutrons and element concentrations determined from analyses of the subsequent gamma-ray spectrum. Results from the two methods are discussed.

  5. North Inlet-Winyah Bay National Estuarine Research Reserve’s (NERR) Estuarine Surface Water Nutrient, Suspended Sediment, and Chlorophyll a Data for the North Inlet and Winyah Bay Estuaries, Georgetown, South Carolina: 2002-2004

    Data.gov (United States)

    Baruch Institute for Marine and Coastal Sciences, Univ of South Carolina — National Estuarine Research Reserve System The National Estuarine Research Reserve System was established by the Coastal Zone Management Act of 1972 (as amended) and...

  6. Characteristics and landcover of estuarine boundaries: implications for the delineation of the South African estuarine functional zone

    CSIR Research Space (South Africa)

    Veldkornet, DA

    2015-11-01

    Full Text Available Zulu-Natal), cultivation has removed estuarine habitat. Although delineation of boundaries can be complicated by landcover changes, the estuarine lateral boundary in Cape estuaries could be identified based on sediment characteristics (moisture content, organic content...

  7. Spatial and seasonal variability of trace-element concentrations in sediments from the Santos-Cubatao estuarine system, Sao Paulo, Brazil

    International Nuclear Information System (INIS)

    Luiz-Silva, Wanilson; Matos, Rosa Helena Ribeiro; Kristosch, Giane Chaves; Machado, Wilson

    2006-01-01

    Multi-element analyses of sediment samples from the Santos-Cubatao Estuarine System were carried out to investigate the spatial and seasonal variability of trace-element concentrations. The study area contains a rich mangrove ecosystem that is a habitat for tens of thousands of resident and migratory birds, some of them endangered globally. Enrichments of metals in fine-grained surface sediments are, in decreasing order, Hg, Mn, La, Ca, Sr, Cd, Zn, Pb, Ba, Cu, Cr, Fe, Nb, Y, Ni and Ga, relative to pre-industrial background levels. The maximum enrichment ranged from 49 (Hg) to 3.1 (Ga). Mercury concentrations were greater in the Cubatao river than in other sites, while the other elements showed greater concentrations in the Morrao river. Concentrations of Mn were significantly greater in winter and autumn than in summer and spring. However, other elements (e.g. Cd and Pb) showed the opposite, with greater concentrations in summer and spring. This study suggests that seasonal changes in physical and chemical conditions may affect the degree of sediment enrichment and therefore make the assessment of contamination difficult. Consequently, these processes need to be considered when assessing water quality and the potential contamination of biota.(author)

  8. Multiple stressor effects on marine infauna: responses of estuarine taxa and functional traits to sedimentation, nutrient and metal loading

    KAUST Repository

    Ellis, Joanne; Clark, D.; Atalah, J.; Jiang, W.; Taiapa, C.; Patterson, M.; Sinner, J.; Hewitt, J.

    2017-01-01

    loading and the documented interaction effects between multiple stressors have important implications for understanding and managing the ecological consequences of eutrophication, sedimentation and contaminants on coastal ecosystems.

  9. Carbohydrates, uronic acids and alkali extractable carbohydrates in contrasting marine and estuarine sediments: Distribution, size fractionation and partial chemical characterization

    Digital Repository Service at National Institute of Oceanography (India)

    Khodse, V.B.; Fernandes, L.; Bhosle, N.B.; Sardessai, S.

    terrestrial plants, bacteria and phytoplankton, however, the influence of the former was relatively greater in sediments of the ME and BOB, as well as in residual sediments of ME. Approximately 11-21% of total carbohydrates could be extracted using hot alkali...

  10. Mercury contamination history of an estuarine floodplain reconstructed from a 210Pb-dated sediment core (Berg River, South Africa)

    CSIR Research Space (South Africa)

    Kading, TJ

    2009-01-01

    Full Text Available in this 210Pb-dated sediment core at <50 ng g_1 HgT throughout the core, but with 1.3 ng g_1 methylmercury in surface sediments. The 210Pb dating of the core provides a first record of mercury deposition to the site and reveals the onset of enhanced mercury...

  11. Assessment of trace metals pollution in estuarine sediments using SEM-AVS and ERM-ERL predictions.

    Science.gov (United States)

    Garcia, Carlos Alexandre Borges; Passos, Elisangela de Andrade; Alves, José do Patrocínio Hora

    2011-10-01

    This paper presents the distributions of the investigation of trace metals geochemistry in surface sediments of the Sergipe river estuary, northeast Brazil. Analyses were carried out by Flame or electrothermal atomic absorption spectrometry (FAAS or ETAAS). Principal component analysis was applied to results to identify any groupings among the different sampling sites. In order to determine the extent of contamination, taking into account natural variability within the region, metal concentrations were normalized relative to aluminium. Cr, Cu, Ni and Zn contamination was observed in sediments from the area receiving highest inputs of domestic wastes, while cadmium contamination occurred in sediments from the region affected by highest inflows of industrial effluents. Possible toxicity related to these metals was examined using the relationship simultaneously extracted metals/acid volatile sulfide and by comparing sediment chemical data with sediment quality guidelines ERL-ERM values. Results obtained using the two methods were in agreement and indicated that adverse effects on aquatic biota should rarely occur.

  12. Validating the use of embryonic fish otoliths as recorders of sublethal exposure to copper in estuarine sediments

    International Nuclear Information System (INIS)

    Barbee, Nicole C.; Greig, Alan; Swearer, Stephen E.

    2013-01-01

    In this study we explore the use of fish otoliths (‘earbones’) as a tool for detecting exposure to heavy metals in sediments. Because otoliths are metabolically inert and incorporate chemical impurities during growth, they can potentially provide a more permanent record of pollutant exposure history in aquatic environments than soft tissues. To validate this technique we cultured embryos of a native Australian fish, the common Galaxias (Galaxias maculatus), in the laboratory on sediments spiked with copper in a concentration gradient. Our aims were to test whether exposure to copper contaminated sediments is recorded in the otoliths of embryos and determine over what range in concentrations we can detect differences in exposure. We found elevated copper levels in otoliths of embryos exposed to high copper concentrations in sediments, suggesting that otoliths can be used as a tool to track a history of exposure to elevated copper levels in the environment. -- Highlights: •Our aim was to determine if exposure to Cu is recorded in embryonic fish otoliths. •Fish eggs were cultured on Cu-spiked sediments in a gradient of concentrations. •Fish do uptake and incorporate Cu into their otoliths during development. •High sediment Cu concentrations resulted in high otolith Cu concentrations. •With further validation, otoliths could be used to track a history of Cu exposure. -- We use sediments spiked with Cu to examine the uptake of heavy metals into embryonic fish otoliths as a novel tool for tracking pollution exposure history

  13. Histological biomarkers in liver and gills of juvenile Solea senegalensis exposed to contaminated estuarine sediments: A weighted indices approach

    International Nuclear Information System (INIS)

    Costa, Pedro M.; Diniz, Mario S.; Caeiro, Sandra; Lobo, Jorge; Martins, Marta; Ferreira, Ana M.; Caetano, Miguel; Vale, Carlos; DelValls, T. Angel; Costa, M. Helena

    2009-01-01

    Young juvenile Solea senegalensis were exposed to three sediments with distinct contamination profiles collected from a Portuguese estuary subjected to anthropogenic sources of contamination (the Sado estuary, western Portugal). Sediments were surveyed for metals (cadmium, chromium, copper, nickel, lead and zinc), a metalloid (arsenic) and organic contaminants (polycyclic aromatic hydrocarbons, polychlorinated biphenyls and a pesticide, dichloro-diphenyl-trichloroethane plus its metabolites), as well as total organic matter, redox potential and particle fine fraction. The fish were exposed to freshly collected sediments in a 28-day laboratorial assay and collected for histological analyses at days 0 (T 0 ), 14 (T 14 ) and 28 (T 28 ). Individual weighted histopathological indices were obtained, based on presence/absence data of eight and nine liver and gill pathologies, respectively, and on their biological significance. Although livers sustained more severe lesions, the sediments essentially contaminated by organic substances caused more damage to both organs than the sediments contaminated by both metallic and organic contaminants, suggesting a possible synergistic effect. Correlation analyses showed that some alterations are linked, forming distinctive histopathological patterns that are in accordance with the severity of lesions and sediment characteristics. The presence of large eosinophilic bodies in liver and degeneration of mucous cells in gills (a first-time described alteration) were some of the most noticeable alterations observed and were related to sediment organic contaminants. Body size has been found to be negatively correlated with histopathological damage in livers following longer term exposures. It is concluded that histopathological indices provide reliable and discriminatory data even when biomonitoring as complex media as natural sediments. It is also concluded that the effects of contamination may result not only from toxicant concentrations

  14. An assessment of mercury in estuarine sediment and tissue in Southern New Jersey using public domain data

    Science.gov (United States)

    Ng, Kara; Szabo, Zoltan; Reilly, Pamela A.; Barringer, Julia; Smalling, Kelly L.

    2016-01-01

    Mercury (Hg) is considered a contaminant of global concern for coastal environments due to its toxicity, widespread occurrence in sediment, and bioaccumulation in tissue. Coastal New Jersey, USA, is characterized by shallow bays and wetlands that provide critical habitat for wildlife but share space with expanding urban landscapes. This study was designed as an assessment of the magnitude and distribution of Hg in coastal New Jersey sediments and critical species using publicly available data to highlight potential data gaps. Mercury concentrations in estuary sediments can exceed 2 μg/g and correlate with concentrations of other metals. Based on existing data, the concentrations of Hg in mussels in southern New Jersey are comparable to those observed in other urbanized Atlantic Coast estuaries. Lack of methylmercury data for sediments, other media, and tissues are data gaps needing to be filled for a clearer understanding of the impacts of Hg inputs to the ecosystem.

  15. Modeling the fate of p,p'-DDT in water and sediment of two typical estuarine bays in South China: Importance of fishing vessels' inputs.

    Science.gov (United States)

    Fang, Shu-Ming; Zhang, Xianming; Bao, Lian-Jun; Zeng, Eddy Y

    2016-05-01

    Antifouling paint applied to fishing vessels is the primary source of dichloro-diphenyl-trichloroethane (DDT) to the coastal marine environments of China. With the aim to provide science-based support of potential regulations on DDT use in antifouling paint, we utilized a fugacity-based model to evaluate the fate and impact of p,p'-DDT, the dominant component of DDT mixture, in Daya Bay and Hailing Bay, two typical estuarine bays in South China. The emissions of p,p'-DDT from fishing vessels to the aquatic environments of Hailing Bay and Daya Bay were estimated as 9.3 and 7.7 kg yr(-1), respectively. Uncertainty analysis indicated that the temporal variability of p,p'-DDT was well described by the model if fishing vessels were considered as the only direct source, i.e., fishing vessels should be the dominant source of p,p'-DDT in coastal bay areas of China. Estimated hazard quotients indicated that sediment in Hailing Bay posed high risk to the aquatic system, and it would take at least 21 years to reduce the hazards to a safe level. Moreover, p,p'-DDT tends to migrate from water to sediment in the entire Hailing Bay and Daya Bay. On the other hand, our previous research indicated that p,p'-DDT was more likely to migrate from sediment to water in the maricultured zones located in shallow waters of these two bays, where fishing vessels frequently remain. These findings suggest that relocating mariculture zones to deeper waters would reduce the likelihood of farmed fish contamination by p,p'-DDT. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Comparison of methods for conducting marine and estuarine sediment porewater toxicity tests—extraction, storage, and handling techniques

    Science.gov (United States)

    Carr, R.S.; Chapman, D.C.

    1995-01-01

    A series of studies was conducted to compare different porewater extraction techniques and to evaluate the effects of sediment and porewater storage conditions on the toxicity of pore water, using assays with the sea urchin Arbacia punctulata. If care is taken in the selection of materials, several different porewater extraction techniques (pressurized squeezing, centrifugation, vacuum) yield samples with similar toxicity. Where the primary contaminants of concern are highly hydrophobic organic compounds, centrifugation is the method of choice for minimizing the loss of contaminants during the extraction procedure. No difference was found in the toxicity of pore water obtained with the Teflon® and polyvinyl chloride pressurized extraction devices. Different types of filters in the squeeze extraction devices apparently adsorbed soluble contaminants to varying degrees. The amount of fine suspended particulate material remaining in the pore water after the initial extraction varied among the methods. For most of the sediments tested, freezing and thawing did not affect the toxicity of porewater samples obtained by the pressurized squeeze extraction method. Pore water obtained by other methods (centrifugation, vacuum) and frozen without additional removal of suspended particulates by centrifugation may exhibit increased toxicity compared with the unfrozen sample.The toxicity of pore water extracted from refrigerated (4°C) sediments exhibited substantial short-term (days, weeks) changes. Similarly, sediment pore water extracted over time from a simulated amphipod solid-phase toxicity test changed substantially in toxicity. For the sediments tested, the direction and magnitude of change in toxicity of pore water extracted from both refrigerated and solid-phase test sediments was unpredictable.

  17. Physicochemical Factors Influence the Abundance and Culturability of Human Enteric Pathogens and Fecal Indicator Organisms in Estuarine Water and Sediment

    Directory of Open Access Journals (Sweden)

    Francis Hassard

    2017-10-01

    Full Text Available To assess fecal pollution in coastal waters, current monitoring is reliant on culture-based enumeration of bacterial indicators, which does not account for the presence of viable but non-culturable or sediment-associated micro-organisms, preventing effective quantitative microbial risk assessment (QMRA. Seasonal variability in viable but non-culturable or sediment-associated bacteria challenge the use of fecal indicator organisms (FIOs for water monitoring. We evaluated seasonal changes in FIOs and human enteric pathogen abundance in water and sediments from the Ribble and Conwy estuaries in the UK. Sediments possessed greater bacterial abundance than the overlying water column, however, key pathogenic species (Shigella spp., Campylobacter jejuni, Salmonella spp., hepatitis A virus, hepatitis E virus and norovirus GI and GII were not detected in sediments. Salmonella was detected in low levels in the Conwy water in spring/summer and norovirus GII was detected in the Ribble water in winter. The abundance of E. coli and Enterococcus spp. quantified by culture-based methods, rarely matched the abundance of these species when measured by qPCR. The discrepancy between these methods was greatest in winter at both estuaries, due to low CFU's, coupled with higher gene copies (GC. Temperature accounted for 60% the variability in bacterial abundance in water in autumn, whilst in winter salinity explained 15% of the variance. Relationships between bacterial indicators/pathogens and physicochemical variables were inconsistent in sediments, no single indicator adequately described occurrence of all bacterial indicators/pathogens. However, important variables included grain size, porosity, clay content and concentrations of Zn, K, and Al. Sediments with greater organic matter content and lower porosity harbored a greater proportion of non-culturable bacteria (including dead cells and extracellular DNA in winter. Here, we show the link between physicochemical

  18. Microplastic pollution in Vembanad Lake, Kerala, India: The first report of microplastics in lake and estuarine sediments in India.

    Science.gov (United States)

    Sruthy, S; Ramasamy, E V

    2017-03-01

    We present the first study of microplastics in the sediments of Vembanad Lake, a Ramsar site in India. Microplastics are emerging pollutants of increasing environmental concern with a particle size of microplastics pollution on the environment and biota is not well known. Vast data exist in the literature on marine microplastics while reports on freshwater ecosystems are scarce. In this context, to examine the occurrence of microplastic particles (MPs) in the Vembanad Lake, samples were collected from ten sites and processed for microplastic extraction through density separation. Identification of the polymer components of MPs was done using micro Raman spectroscopy. MPs were recovered from all sediment samples, indicating their extensive distribution in the lake. The abundance of MPs recorded from the sediment samples is in the range of 96-496 particles m -2 with a mean abundance of 252.80 ± 25.76 particles m -2 . Low density polyethylene has been identified as the dominant type of polymer component of the MPs. As clams and fishes are the major source of protein to the local population, the presence of MPs in the lake becomes critically important, posing a severe threat of contaminating the food web of this lake. This study, being the first report from India on MPs in lake sediments, provide impetus for further research on the distribution and impact of this emerging pollutant on the biota of many aquatic systems spread across India. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Multiple stressor effects on marine infauna: responses of estuarine taxa and functional traits to sedimentation, nutrient and metal loading

    KAUST Repository

    Ellis, Joanne

    2017-09-14

    Sedimentation, nutrients and metal loading to coastal environments are increasing, associated with urbanization and global warming, hence there is a growing need to predict ecological responses to such change. Using a regression technique we predicted how maximum abundance of 20 macrobenthic taxa and 22 functional traits separately and interactively responded to these key stressors. The abundance of most taxa declined in response to sedimentation and metal loading while a unimodal response was often associated with nutrient loading. Optimum abundances for both taxa and traits occurred at relatively low stressor levels, highlighting the vulnerability of estuaries to increasing stressor loads. Individual taxa were more susceptible to stress than traits, suggesting that functional traits may be less sensitive for detecting changes in ecosystem health. Multiplicative effects were more common than additive interactions. The observed sensitivity of most taxa to increasing sedimentation and metal loading and the documented interaction effects between multiple stressors have important implications for understanding and managing the ecological consequences of eutrophication, sedimentation and contaminants on coastal ecosystems.

  20. Estuarine Ecosystem Engineering : Biogeomorphology in the estuarine intertidal

    NARCIS (Netherlands)

    Montserrat Trotsenburg, F.

    2011-01-01

    The aim of this thesis was to investigate how (macro)benthic organisms interact with the ecological functioning, erodibility and small- to medium-scale morphodynamics of estuarine intertidal sediment by modulating its composition and/or properties. In these interactions, scale is of great importance

  1. 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)

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

    2011-11-01

    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. Copyright © 2011 Elsevier Ltd. All rights reserved.

  2. Transcriptomic analyses in a benthic fish exposed to contaminated estuarine sediments through laboratory and in situ bioassays.

    Science.gov (United States)

    Costa, Pedro M; Miguel, Célia; Caeiro, Sandra; Lobo, Jorge; Martins, Marta; Ferreira, Ana M; Caetano, Miguel; Vale, Carlos; DelValls, T A; Costa, Maria H

    2011-11-01

    The transcription of contaminant response-related genes was investigated in juvenile Senegalese soles exposed to sediments from three distinct sites (a reference plus two contaminated) of a Portuguese estuary (the Sado, W Portugal) through simultaneous 28-day laboratory and in situ bioassays. Transcription of cytochrome P450 1A (CYP1A), metallothionein 1 (MT1), glutathione peroxidase (GPx), catalase (CAT), caspase 3 (CASP3) and 90 kDa heat-shock protein alpha (HSP90AA) was surveyed in the liver by real-time PCR. CASP3 transcription analysis was complemented by surveying apoptosis through the TUNEL reaction. After 14 days of exposure, relative transcription was either reduced or decreased in fish exposed to the contaminated sediments, revealing a disturbance stress phase during which animals failed to respond to insult. After 28 days of exposure all genes' transcription responded to contamination but laboratory and in situ assays depicted distinct patterns of regulation. Although sediments revealed a combination of organic and inorganic toxicants, transcription of the CYP1A gene was consistently correlated to organic contaminants. Metallothionein regulation was found correlated to metallic and organic xenobiotic contamination in the laboratory and in situ, respectively. The transcription of oxidative stress-related genes can be a good indicator of general stress but caution is mandatory when interpreting the results since regulation may be influenced by multiple factors. As for MT1, HSP90 up-regulation has potential to be a good indicator for total contamination, as well as the CASP3 gene, even though hepatocyte apoptosis depicted values inconsistent with sediment contamination, showing that programmed cell death did not directly depend on caspase transcription alone.

  3. Effects of Spartina alterniflora invasion on the communities of methanogens and sulfate-reducing bacteria in estuarine marsh sediments

    Directory of Open Access Journals (Sweden)

    Jemaneh eZeleke

    2013-08-01

    Full Text Available The effect of plant invasion on the microorganisms of soil sediments is very important for estuary ecology. The community structures of methanogens and sulfate-reducing bacteria (SRB as a function of Spartina alterniflora invasion in Phragmites australis-vegetated sediments of the Dongtan wetland in the Yangtze River estuary, China, were investigated using 454 pyrosequencing and quantitative real-time PCR (qPCR of the methyl coenzyme M reductase A (mcrA and dissimilatory sulfite-reductase (dsrB genes. Sediment samples were collected from two replicate locations, and each location included three sampling stands each covered by monocultures of P. australis, S. alterniflora and both plants (transition stands, respectively. qPCR analysis revealed higher copy numbers of mcrA genes in sediments from S. alterniflora stands than P. australis stands (5- and 7.5-fold more in the spring and summer, respectively, which is consistent with the higher methane flux rates measured in the S. alterniflora stands (up to 8.01 ± 5.61 mg m-2 h-1. Similar trends were observed for SRB, and they were up to two orders of magnitude higher than the methanogens. Diversity indices indicated a lower diversity of methanogens in the S. alterniflora stands than the P. australis stands. In contrast, insignificant variations were observed in the diversity of SRB with the invasion. Although Methanomicrobiales and Methanococcales, the hydrogenotrophic methanogens, dominated in the salt marsh, Methanomicrobiales displayed a slight increase with the invasion and growth of S. alterniflora, whereas the later responded differently. Methanosarcina, the metabolically diverse methanogens, did not vary with the invasion of, but Methanosaeta, the exclusive acetate utilizers, appeared to increase with S. alterniflora invasion. In SRB, sequences closely related to the families Desulfobacteraceae and Desulfobulbaceae dominated in the salt marsh, although they displayed minimal changes with the S

  4. Accumulation and partitioning of seven trace metals in mangroves and sediment cores from three estuarine wetlands of Hainan Island, China

    International Nuclear Information System (INIS)

    Qiu Yaowen; Yu Kefu; Zhang Gan; Wang Wenxiong

    2011-01-01

    Trace metals in mangrove tissues (leaf, branch, root and fruit) of nine species and sediments of ten cores collected in 2008 from Dongzhai Harbor, Sanya Bay and Yalong Bay, Hainan Island, were analyzed. The average concentrations of Cu, Pb, Zn, Cd, Cr, Hg and As in surface sediments were 14.8, 24.1, 57.9, 0.17, 29.6, 0.08 and 9.7 μg g -1 , whereas those in mangrove tissues were 2.8, 1.4, 8.7, 0.03, 1.1, 0.03, and 0.2 μg g -1 , respectively. Compared to those from other typical mangrove wetlands of the world, the metal levels in Hainan were at low- to median-levels, which is consistent with the fact that Hainan Island is still in low exploitation and its mangroves suffer little impact from human activities. Metal concentrations among different tissues of mangroves were different. In general, Zn and Cu were enriched in fruit, Hg was enriched in leaf, Pb, Cd and Cr were enriched in branch, and As was enriched in root. The cycle of trace metals in mangrove species were estimated. The biota-sediment accumulation factors (BSAFs) followed the sequence of Hg (0.43) > Cu (0.27) > Cd (0.22) > Zn (0.17) > Pb (0.07) > Cr (0.06) > As (0.02).

  5. Accumulation and partitioning of seven trace metals in mangroves and sediment cores from three estuarine wetlands of Hainan Island, China

    Energy Technology Data Exchange (ETDEWEB)

    Qiu Yaowen, E-mail: yqiu@scsio.ac.cn [State Key Laboratory of Tropic Marine Environment, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301 (China); Yu Kefu [State Key Laboratory of Tropic Marine Environment, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301 (China); Zhang Gan [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Wang Wenxiong [Section of Marine Ecology and Biotechnology, Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong (Hong Kong)

    2011-06-15

    Trace metals in mangrove tissues (leaf, branch, root and fruit) of nine species and sediments of ten cores collected in 2008 from Dongzhai Harbor, Sanya Bay and Yalong Bay, Hainan Island, were analyzed. The average concentrations of Cu, Pb, Zn, Cd, Cr, Hg and As in surface sediments were 14.8, 24.1, 57.9, 0.17, 29.6, 0.08 and 9.7 {mu}g g{sup -1}, whereas those in mangrove tissues were 2.8, 1.4, 8.7, 0.03, 1.1, 0.03, and 0.2 {mu}g g{sup -1}, respectively. Compared to those from other typical mangrove wetlands of the world, the metal levels in Hainan were at low- to median-levels, which is consistent with the fact that Hainan Island is still in low exploitation and its mangroves suffer little impact from human activities. Metal concentrations among different tissues of mangroves were different. In general, Zn and Cu were enriched in fruit, Hg was enriched in leaf, Pb, Cd and Cr were enriched in branch, and As was enriched in root. The cycle of trace metals in mangrove species were estimated. The biota-sediment accumulation factors (BSAFs) followed the sequence of Hg (0.43) > Cu (0.27) > Cd (0.22) > Zn (0.17) > Pb (0.07) > Cr (0.06) > As (0.02).

  6. An experimental study on dredge spoil of estuarine sediments in the bay of seine (France): A morphosedimentary assessment

    Science.gov (United States)

    Marmin, Stella; Lesueur, Patrick; Dauvin, Jean Claude; Samson, Sandrine; Tournier, Patrice; Gallicher Lavanne, Albert; Dubrulle-Brunaud, Carole; Thouroude, Coralie

    2016-03-01

    Studies on the consequences of dredging on estuarine morphology and its sedimentary dynamics are common, but the impacts of dumping dredge spoil in coastal open settings are rarely found in scientific literature. An experimental study was conducted over the period 2012-2013 to monitor the physical impacts of dredged material dumped at two adjacent sites (one million cubic metres at each) on the inner shelf of the Bay of Seine in France (eastern part of the English Channel, La Manche). As recently reinforced in the EU Marine Strategy Framework Directive (MSFD), knowledge on the location and intensity of human impacts (e.g. on marine ecosystems) is critical for effective marine management and conservation. So, two methods of disposition were tested to evaluate the impacts of dumping on the environment and thus propose recommendations for future dumping. The strategy is based on a Before-After-Control-Impact (BACI) approach, in which the spatio-temporal variability was studied by analysing the morphological and sedimentological characteristics over a period of 28 months, from November 2011 to April 2014, also including recovery of the seafloor after cessation of the dumping activities. The first experimental dumping operation (MASED) was carried out regularly for 8 months at a single point and generating a conical deposit of 5 m in height, while the second dumping (MABIO) lasted for 12 months involving four steps in the dumping process. In the second case, a wider area was covered, leading to the formation of a smaller deposit of 2 m in height. The dumped deposits consisted of muddy fine sand, whereas the inner shelf seafloor in this area is covered with fine to medium sand. As a result, muddy fine sand accumulated at or near the two dumping sites, with a maximum mud (i.e. particles4 Φ) content of 50% compared todredged material remained at the end of the dumping periods. After dumping ceased, a further 5% of material for MABIO and 20% for MASED, was transported out

  7. Determination of selected metals in urban runoff and related estuarine sediments by neutron activation and atomic absorption

    International Nuclear Information System (INIS)

    Christensen, E.R.; Guinn, V.P.; Scherfig, J.

    1977-01-01

    Pollution sources for Newport Bay, California are of a nonpoint nature. To assess the heavy metals loading of the runoff into the Bay, 18 water samples, taken during dry and rainy periods, have been analyzed for Mn, Cu, Zn, and Pb, using atomic absorption spectrometry (AAS). In addition, 7 sediment cores from the Upper Bay and 5 sediment grab samples from the Lower Bay were analyzed for Cr, Mn, Fe, Co, Cu, Zn, and Pb. Instrumental neutron activation analysis (INAA) was used for Cr, Fe, and Co, whereas Mn, Cu, and Pb were determined by AAS. Zinc was determined by both of these techniques. Three major streams pass into Newport Bay carrying: (1) agricultural and to some extent urban and residential runoff (70-90%), (2) urban runoff (10-30%), and (3) residential runoff (<5%). The levels of Zn and Pb are much higher under storm conditions, e.g., 338 μg/l Zn and 425 μg/l Pb, than during dry weather, where typical concentrations are 20 μg/l Zn and 9 μg/l Pb. For Cu there is a moderate increase from about 10 μg/l in dry weather to a maximum of 54 μg/l under storm conditions. Soil erosion appears to be responsible for high Mn values (max. 1230 μg/l) in agricultural storm runoff. The cleansing action of a storm is evidenced by high concentrations in the beginning, and much lower levels towards the end of the storm.Vertical profiles of heavy metals in sediment cores indicate that Zn and Pb are the only metals of those investigated that show clearly increased levels in the uppermost layers. Typical enrichment ratios are 2.0 for Zn and 5.5 for Pb. Maximum concentrations of Zn and Pb in sediments from the Upper Bay were 300 ppm and 132 ppm, respectively. The highest Pb value was found close to the mouth of the urban drainage channel. Dating of selected cores was carried out by the Pb-210 method. Mass injection rates into Upper Newport Bay for Zn and Pb of anthropogenic origin were estimated to be 6.0 and 6.5 tons/yr, respectively

  8. Metal and trace element sediment assessment from two estuarine systems: Santos/Sao Vicente and Cananeia, State of Sao Paulo, Brazil

    International Nuclear Information System (INIS)

    Amorim, Eduardo Paulo de

    2012-01-01

    This study evaluated some toxic metals such as Cd, Hg and Pb and some other major and trace elements in surface sediment samples, from two different systems under different degrees of anthropogenic actions: the estuarine system of Santos/Sao Vicente and the southern part of the Cananeia estuary, both on the Sao Paulo state coast. Sediment samples were collected in 16 stations in the Santos/Sao Vicente estuary and 13 stations in the Cananeia estuary, during summer and winter of 2005 and 2006, in both estuaries. Three analytical techniques were used: NAA, AAS and ICP OES. NAA was used for the quantification of major element concentration levels (Ca, Fe and Na), trace elements (As, Ba, Br, Cd, Co, Cu, Cr, Cs, Hf, Rb, Sb, Sc, Se, Ta, Th, U, and Zn and rare earths elements La, Ce, Eu, Nd, Sm, Lu, Tb, Yb). ICP OES was used for determination of the concentration levels of Al, Ba, Be, Bi, B, Cd, Co, Pb, Cu, Cr, Sn, Sr, Fe, Li, Mn, Mo, Ni, Tl, Ti, V and Zn. AAS for Cd and Pb quantification through graphite furnace (GF AAS) and Hg through cold vapor generation (CV AAS). Methodology validation according to precision and accuracy was performed by reference material analyses for the three analytical techniques used. Detection and quantification limits were calculated for each element evaluated. Seasonal variations (summer and winter), spatial and temporal (2005 e 2006) variations of metals and trace elements were also evaluated. In the Santos estuary, in general, metal and trace element concentrations , organic matter content and % of pelitic fraction found in the Santos channel (area 1) were higher than those of the Santos Bay (area 2) and Sao Vicente channel (area 3). Area 1 suffers high impact from industrial activities from the Cubatao region and Santos port. The sediments from station 14 (area 3, Sao Vicente channel), showed the same behavior of those from area 1, suffering influence from the industrial pole and located in a mangrove area. In comparison with TEL and PEL

  9. Use of principal components analysis (PCA) on estuarine sediment datasets: The effect of data pre-treatment

    International Nuclear Information System (INIS)

    Reid, M.K.; Spencer, K.L.

    2009-01-01

    Principal components analysis (PCA) is a multivariate statistical technique capable of discerning patterns in large environmental datasets. Although widely used, there is disparity in the literature with respect to data pre-treatment prior to PCA. This research examines the influence of commonly reported data pre-treatment methods on PCA outputs, and hence data interpretation, using a typical environmental dataset comprising sediment geochemical data from an estuary in SE England. This study demonstrated that applying the routinely used log (x + 1) transformation skewed the data and masked important trends. Removing outlying samples and correcting for the influence of grain size had the most significant effect on PCA outputs and data interpretation. Reducing the influence of grain size using granulometric normalisation meant that other factors affecting metal variability, including mineralogy, anthropogenic sources and distance along the salinity transect could be identified and interpreted more clearly. - Data pre-treatment can have a significant influence on the outcome of PCA.

  10. Isolation from estuarine sediments of a Desulfovibrio strain which can grow on lactate coupled to the reductive dehalogenation of 2,4,6-tribromophenol

    Energy Technology Data Exchange (ETDEWEB)

    Boyle, A.W.; Phelps, C.D.; Young, L.Y. [Rutgers-The State Univ. of New Jersey, New Brunswick, NJ (United States). Biotechnology Center for Agriculture and the Environment

    1999-03-01

    Strain TBP-1, an anaerobic bacterium capable of reductively dehalogenating 2,4,6-tribromophenol to phenol, was isolated from estuarine sediments of the Arthur Kill in the New York/New Jersey harbor. It is a gram-negative, motile, vibrio-shaped, obligate anaerobe which grows on lactate, pyruvate, hydrogen, and fumarate when provided sulfate as an electron acceptor. The organism accumulates acetate when grown on lactate and sulfate, contains desulfoviridin, and will not grow in the absence of NaCl. It will not utilize acetate, succinate, propionate, or butyrate for growth via sulfate reduction. When supplied with lactate as an electron donor, strain TBP-1 will utilize sulfate, sulfite, sulfur, and thiosulfate for growth but not nitrate, fumarate, or acrylate. This organism debrominates 2-, 4-, 2,4-, 2,6-, and 2,4,6-bromophenol but not 3- or 2,3-bromophenol or monobrominated benzoates. It will not dehalogenate monochlorinated, fluorinated, or iodinated phenols or chlorinated benzoates. Together with its physiological characteristics, its 16S rRNA gene sequence places it in the genus Desulfovibrio. The average growth yield of strain TBP-1 grown on a defined medium supplemented with lactate and 2,4,6-bromophenol is 3.71 mg of protein/mmol of phenol produced, and the yield was 1.42 mg of protein/mmol of phenol produced when 40bromophenol was the electron acceptor. Average growth yields for Desulfovibrio sp. strain TBP-1 grown with 2,4,6-bromophenol, 4-bromophenol, or sulfate are 0.62, 0.71, and 1.07, respectively. Growth did not occur when either lactate or 2,4,6-bromophenol was omitted from the growth medium. These results indicate that Desulfovibrio sp. strain TBP-1 is capable of growth via halorespiration.

  11. A Study on the Environmental Standard of Sediment on the Bottom of the Water

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chang Hee; Yoo, Hye Jin [Korea Environment Institute, Seoul (Korea)

    2000-12-01

    Sediment on the bottom of the water has been considered one of the water pollutants in the environmental management of Korea so treated as a management on pollutants, as you can see the examples in the dragging operation in the polluted sea area. To healthily maintain and conserve the water ecosystem including bottom living things in the water, sediment on the bottom of the water should be recognized as the independent medium, which should maintain the certain quality like the water, the atmosphere, and soil, rather than the source of water pollution. Such recognition means that the management of sediment on the bottom of the water should change the fragmentary goal, centered the post management focusing on the water management, to the ecosystematic goal including the bottom living things. In a point of the view, this study has a great significance to suggest not only the final goal for the management of sediment on the bottom of the water but also the necessity of developing the environmental standard of the sediment on the bottom of the water, which is a standard of the management or judgment in the actual managing the sediment on the bottom of the water - an estimation on the pollution of sediment, a removal of the polluted sediment, a purification of sediment, and an abandonment of the dragged sediment -, and the development measures. Considering the situation that even the basic scheme related to the management of sediment is not prepared in the Government level, the concept of the environmental standard of sediment, the foreign example of the environmental standard of sediment, the current state of the domestic sediment pollution, and the development scheme of the environmental standard in this study must be the important foundation to establish the management system of sediment in the Government level. 121 refs., 10 figs., 45 tabs.

  12. An approach to standardization of urine sediment analysis via suggestion of a common manual protocol.

    Science.gov (United States)

    Ko, Dae-Hyun; Ji, Misuk; Kim, Sollip; Cho, Eun-Jung; Lee, Woochang; Yun, Yeo-Min; Chun, Sail; Min, Won-Ki

    2016-01-01

    The results of urine sediment analysis have been reported semiquantitatively. However, as recent guidelines recommend quantitative reporting of urine sediment, and with the development of automated urine sediment analyzers, there is an increasing need for quantitative analysis of urine sediment. Here, we developed a protocol for urine sediment analysis and quantified the results. Based on questionnaires, various reports, guidelines, and experimental results, we developed a protocol for urine sediment analysis. The results of this new protocol were compared with those obtained with a standardized chamber and an automated sediment analyzer. Reference intervals were also estimated using new protocol. We developed a protocol with centrifugation at 400 g for 5 min, with the average concentration factor of 30. The correlation between quantitative results of urine sediment analysis, the standardized chamber, and the automated sediment analyzer were generally good. The conversion factor derived from the new protocol showed a better fit with the results of manual count than the default conversion factor in the automated sediment analyzer. We developed a protocol for manual urine sediment analysis to quantitatively report the results. This protocol may provide a mean for standardization of urine sediment analysis.

  13. Estuarine and marine geology (2011-2015)

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, V.P.; Chakraborty, P.

    . Detailed studies on rock-magnetic properties and delta 13Corg in sediments off the Krishna-Godavari provide evidence of reductive diagenesis, formation of authigenic sulfides and occurrence of methane in these estuarine sediments and also...

  14. Ecology of Estuarine Macrobenthos

    NARCIS (Netherlands)

    Herman, P.M.J.; Middelburg, J.J.; Koppel, J. van de; Heip, C.H.R.

    1999-01-01

    Macrobenthos is an important component of estuarine ecosystems. Based on a cross-system comparison, we show that estuarine macrobenthos may directly process a significant portion of the system-wide primary production, and that estuarine macrobenthic biomass may be predicted from primary production

  15. Identification and effects of anthropogenic emissions of U and Th on the composition of sediments in a river/estuarine system in Southern Spain

    International Nuclear Information System (INIS)

    Martinez-Aguirre, A.; Garcia-Leon, M.

    1994-01-01

    A study of the distribution of natural radionuclides in different fractions of river bottom sediments has been carried out. The study has shown that the majority of the total U in the sediment is located in the non-residual fraction of the sediment, while Th is more suitable to be present in the residual fraction of the sediments. Also, it has been found that coprecipitation with amorphous ferromanganese oxyhydroxides is the main process of incorporation of U- and Th-isotopes from the water column to suspended matter or bottom sediments. The distribution of the radionuclides and the analysis of some relevant activity ratios in different fractions of sediments has made an unequivocal connection between the enhanced U content in river sediments and the waste discharged into the Odiel and Tinto rivers by the operation in the vicinity of phosphate fertilizer industries. (Author)

  16. Growth Characteristics of an Estuarine Heterocystous Cyanobacterium

    NARCIS (Netherlands)

    Guimarães, P.; Yunes, J.S.; Cretoiu, M.S.; Stal, L.J.

    2017-01-01

    A new estuarine filamentous heterocystous cyanobacterium was isolated from intertidal sediment of the Lagoa dos Patos estuary (Brazil). The isolate may represent a new genus related to Cylindrospermopsis. While the latter is planktonic, contains gas vesicles, and is toxic, the newly isolated strain

  17. Estuarine turbidity, flushing, salinity, and circulation

    Science.gov (United States)

    Pritchard, D. W.

    1972-01-01

    The effects of estuarine turbidity, flushing, salinity, and circulation on the ecology of the Chesapeake Bay are discussed. The sources of fresh water, the variations in salinity, and the circulation patterns created by temperature and salinity changes are analyzed. The application of remote sensors for long term observation of water temperatures is described. The sources of sediment and the biological effects resulting from increased sediments and siltation are identified.

  18. Sediment nickel bioavailability and toxicity to estuarine crustaceans of contrasting bioturbative behaviors--an evaluation of the SEM-AVS paradigm.

    Science.gov (United States)

    Chandler, G Thomas; Schlekat, Christian E; Garman, Emily R; He, Lijian; Washburn, Katherine M; Stewart, Emily R; Ferry, John L

    2014-11-04

    Robust sediment quality criteria require chemistry and toxicity data predictive of concentrations where population/community response should occur under known geochemical conditions. Understanding kinetic and geochemical effects on toxicant bioavailability is key, and these are influenced by infaunal sediment bioturbation. This study used fine-scale sediment and porewater measurement of contrasting infaunal effects on carbon-normalized SEM-AVS to evaluate safe or potentially toxic nickel concentrations in a high-binding Spartina saltmarsh sediment (4%TOC; 35-45 μmol-S2-·g(-1)). Two crustaceans producing sharply contrasting bioturbation--the copepod Amphiascus tenuiremis and amphipod Leptocheirus plumulosus--were cultured in oxic to anoxic sediments with SEM[Ni]-AVS, TOC, porewater [Ni], and porewater DOC measured weekly. From 180 to 750 μg-Ni·g(-1) sediment, amphipod bioturbation reduced [AVS] and enhanced porewater [Ni]. Significant amphipod uptake, mortality, and growth-depression occurred at the higher sediment [Ni] even when [SEM-AVS]/foc suggested acceptable risk. Less bioturbative copepods produced higher AVS and porewater DOC but exhibited net population growth despite porewater [Ni] 1.3-1.7× their aqueous [Ni] LOEC. Copepod aqueous tests with/without dissolved organic matter showed significant aqueous DOC protection, which suggests porewater DOC attenuates sediment Ni toxicity. The SEM[Ni]-AVS relationship was predictive of acceptable risk for copepods at the important population-growth level.

  19. Evaluation of mercury contamination in sediments from Santos - Sao Vicente Estuarine system, in period of 1996 -2000; Avaliacao da contaminacao por mercurio dos sedimentos do Estuario Santos - Sao Vicente, no periodo de 1996-2000

    Energy Technology Data Exchange (ETDEWEB)

    Hortellani, Marcos Antonio

    2003-07-01

    The distribution of mercury contamination in the Santos - Sao Vicente Estuarine System was observed through the analysis of seventy seven surface sediments samples collected in two series. In different periods and points, since the Channel of Piacaguera, the head of the system, , through the estuarine arms of Santos and Sao Vicente as far as the Bay of Santos, about 30 Km downstream, and in different mangrove areas, including industrial and harbor influence zones. The obtained values ranged from 0.03 to 1.19 {mu}g g {sup -1} About 90% of the samples of the first series collected among 1997-1998 and 50% of the second series collected among 1999-2000 presented levels of Hg > 0,13 {mu}g g {sup -1} ,limit considered by the Canadian legislation and adopted by CETESB, below which doesn't happen adverse effect in the biological community. And about 35% of samples of the first series and 11 % of the second series presented concentrations of Hg > 0.698 {mu}g g {sup -1} probable level of occurrence of adverse effect in the biological community. These results indicate an increase of the mercury levels caused by the industrial, port and urban activities. The mercury concentration in sediments was determined by using an Atomic Absorption Spectrophotometer, coupling with a flow injection system by a cold vapor generation, using a manual injection valve (FIA-CVAAS). The estimate of the uncertainties associated to this procedure was calculated. The following elements were also determined: Fe, Al, Zn, Ni, Pb, Cd, Cr and Co in 46 samples of the second series, by atomic absorption spectrometry. In order to verify possible relationship among all the investigated elements in the samples sediments, was carried out a statistical study, using the SPSS-8.0 software. Pearson correlation and Principal Component's analysis were used for with the objective to identify of major relationship for additional exploration of the general behavior of the data. (author)

  20. Application of sequential leaching, risk indices and multivariate statistics to evaluate heavy metal contamination of estuarine sediments: Dhamara Estuary, East Coast of India.

    Science.gov (United States)

    Asa, Subas Chandra; Rath, Prasanta; Panda, Unmesh Chandra; Parhi, Pankaj Kumar; Bramha, Satyanarayan

    2013-08-01

    In the present study, concentration of some selected trace metals (Fe, Mn, Ni, Co, Pb, Zn, Cu, Cr and Cd) are measured in Brahmani, Baitarani river complex along with Dhamara estuary and its near shore. Chemical partitioning has been made to establish association of metals into different geochemical phases. The exchangeable fraction is having high environmental risk among non-lithogeneous phases due to greater potential for mobility into pore water. The metals with highest bio-availability being Cd, Zn and Cr. The metals like Mn, Zn, Cd and Cu represent an appreciable portion in carbonate phase. Fe-Mn oxides act as efficient scavenger for most of the metals playing a prime role in controlling their fate and transport. Among non-lithogeneous phases apart from reducible, Cr showed a significant enrichment in organic phase. Risk assessment code values indicate that all metals except Fe fall under medium-risk zone. In estuarine zone Cd, Zn, Pb and Cr are released to 32.43, 26.10, 21.81 and 20 %, respectively, indicating their significant bio-availability pose high ecological risk. A quantitative approach has been made through the use of different risk indices like enrichment factor, geo-accumulation index and pollution load index. Factor analysis indicates that in riverine zone, Fe-Mn oxides/hydroxides seem to play an important role in scavenging metals, in estuarine zone, organic precipitation and adsorption to the fine silt and clay particles while in coastal zone, co-precipitation with Fe could be the mechanism for the same. Canonical discriminant function indicates that it is highly successful in discriminating the groups as predicted.

  1. Use of 16S rRNA-targeted oligonucleotide probes to investigate the distribution of sulphate-reducing bacteria in estuarine sediments.

    Science.gov (United States)

    Purdy, K J.; Nedwell, D B.; Embley, T M.; Takii, S

    2001-07-01

    The distribution of sulphate-reducing bacteria (SRBs) in three anaerobic sediments, one predominantly freshwater and low sulphate and two predominantly marine and high sulphate, on the River Tama, Tokyo, Japan, was investigated using 16S rRNA-targeted oligonucleotide probes. Hybridisation results and sulphate reduction measurements indicated that SRBs are a minor part of the bacterial population in the freshwater sediments. Only Desulfobulbus and Desulfobacterium were detected, representing 1.6% of the general bacterial probe signal. In contrast, the SRB community detected at the two marine-dominated sites was larger and more diverse, representing 10-11.4% of the bacterial signal and with Desulfobacter, Desulfovibrio, Desulfobulbus and Desulfobacterium detected. In contrast to previous reports our results suggest that Desulfovibrio may not always be the most abundant SRB in anaerobic sediments. Acetate-utilising Desulfobacter were the dominant SRB in the marine-dominated sediments, and Desulfobulbus and Desulfobacterium were active in low-sulphate sediments, where they may utilise electron acceptors other than sulphate.

  2. Uranium content and dose assessment for sediment and soil samples from the estuarine system of Santos and Sao Vicente, SP (Brazil)

    International Nuclear Information System (INIS)

    Geraldo, L. P.; Serafim, R. A. M.; Correa, B. A. M.; Yamazaki, I. M.; Primi, M. C.

    2010-01-01

    In this work, the uranium (U) content in sediment and soil samples collected near the Santos and Sao Vicente estuaries was determined using the fission track registration technique (SSNTD). The sediment and soil samples after oven-dried and pulverised were prepared in the solution form. About 10 ml of this solution was deposited on a plastic detector and irradiated at the IPEN-IEA-R1 (3.5 MW) nuclear reactor. After the irradiation and chemical etching of the plastic foils, the fission tracks were counted with a system consisting of an optical microscope together with a video camera and a PC. The U content in the analysed samples ranged from 3.12±0.55 to 18.3±1.2 ppm for sediments and from 3.21±0.63 to 11.5±1.1 ppm for soils or in terms of 238 U equivalent activity from 38.5±6.8 to 226±15 and 39.6±7.8 to 142±14 Bq kg -1 for sediments and soils, respectively. These results were compared with other values reported in the literature for sediments and soils collected in environments similar to the ones studied in this work. Most of the values obtained in this work are higher than the world mean and are in reasonable agreement with results found by other authors for sediments and soils from regions considered as polluted or with a high level of radioactivity. (authors)

  3. REE in suspended particulate matter and sediment of the Zuari estuary and adjacent shelf, western India: Influence of mining and estuarine turbidity

    Digital Repository Service at National Institute of Oceanography (India)

    Shynu, R.; Rao, V.P.; Parthiban, G.; Balakrishnan, S.; Narvekar, T.; Kessarkar, P.M.

    in the development of ETM in the lower estuary (Rao et al., 2011). As a consequence bottom sediment may have been re-suspended, thereby increasing SPM and REE in the water column and mixed up with the sediment brought by the river. In other words, the REE.... Seminar Volume on Earth Resources for Goa’s Development. Geological Survey of India, pp. 1-13. Goldstein, S.J., Jacobsen, S.B., 1988. Rare earth elements in river waters. Earth Planetary Science Letters 89, 35-47. Govindaraju, K., 1994. Compilation...

  4. ACUTE TOXICITY OF FIVE SEDIMENT-ASSOCIATED METALS, INDIVIDUALLY AND IN A MIXTURE, TO THE ESTUARINE MEIOBENTHIC HARPACTICOID COPEPOD AMPHIASCUS TENUIREMIS. (R825279)

    Science.gov (United States)

    AbstractThe acute effects of many individual, seawater-solubilized metals on meiobenthic copepods and nematodes are well known. In sediments, however, metals most often occur as mixtures, and it is not known whether such mixtures exhibit simple additive toxicity to me...

  5. Trace elements in bottom sediments of the Barents Sea on the standard section "Kola Meridian"

    Directory of Open Access Journals (Sweden)

    Lapteva A. M.

    2017-03-01

    Full Text Available The levels of trace metals (Cu, Zn, Ni, Cr, Mn, Co, Pb, Cd, Hg and arsenic (As in samples of bottom sediments from the Barents Sea on eight stations of the standard section "Kola Meridian" have been investigated. Trace elements have been determined on atomic absorption spectrophotometer AA-6800 with mercury-hydride attachment HVG-1 of the company Shimadzu (Japan by the methods of flaming (acetylene – air and electrothermal atomization. Common and very toxic trace elements include Pb, Cd, As, and Hg. It is believed that 90 % of lead, 70–80 % of cadmium, and arsenic, over 30 % of mercury in the atmosphere are of anthropogenic origin, and emissions of these elements in the atmosphere are almost completely manufactured in the Northern Hemisphere. The main sources of income in the Barents Sea are waters of the North Atlantic current and the large-scale atmospheric transport from industrialized Central Europe. As a rule the spatial distribution of trace elements is in good agreement with the granulometric composition of bottom sediments and the content of organic carbon. The contents of most of the listed trace elements in samples of bottom sediments on the standard section "Kola Meridian" in the Norwegian classification are consistent with background levels with the exception of Ni, Cr, and As. Their content in bottom sediments at some stations has met the criteria for "slight" and "moderate" pollution. The obtained results confirm the insignificant levels of contamination of bottom sediments of some trace elements. On the status of stocks of commercial species of aquatic biological resources, the observed levels of contamination of bottom sediments in the investigated areas of the Barents Sea will have no significant effect

  6. Impact of terrestrial mining and intensive agriculture in pollution of estuarine surface sediments: Spatial distribution of trace metals in the Gulf of Urabá, Colombia.

    Science.gov (United States)

    Vallejo Toro, Pedro Pablo; Vásquez Bedoya, Luis Fernando; Correa, Iván Darío; Bernal Franco, Gladys Rocío; Alcántara-Carrió, Javier; Palacio Baena, Jaime Alberto

    2016-10-15

    The Gulf of Urabá (northwestern Colombia) is a geostrategic region, rich in biodiversity and natural resources. Its economy is mainly based on agribusinesses and mining activities. In this research is determined the impact of these activities in bottom surface sediments of the estuary. Thus, grain size, total organic carbon, total nitrogen, carbonates, Ag, Al, Ca, Cr, Cu, Fe, Hg, Mg, Mn, Ni, Pb and Zn concentrations from 17 surface sediment samples were obtained and enrichment factors (EF) as well as geo-accumulation indices (Igeo) were calculated to determine the contamination level in the gulf. EF and Igeo values revealed that the estuary is extremely contaminated with Ag and moderately contaminated with Zn. Therefore, the observed enrichment of Ag may be explained as a residue of the extraction of gold and platinum-group metals and the enrichment with Zn associated mainly to pesticides used in banana plantations. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Chemical elements in pearl oysters (Paxyodon ponderosus), phytoplankton and estuarine sediments from eastern Amazon (Northern Brazil): Bioaccumulation factors and trophic transfer factors

    Science.gov (United States)

    Vilhena, Maria P. S. P.; Costa, Marcondes L.; Berrêdo, José F.; Paiva, Rosildo S.; Souza, Crisvaldo C. S.

    2016-04-01

    The current study was conducted near Barcarena County, which is a mid-sized urban center where aluminum ore processing industries (bauxite) and Vila do Conde cargo terminal are located. It aims to discuss the bioaccumulation factors as well as factors related to the trophic transfer of chemical elements in water, oyster, phytoplankton and bottom sediments from an estuary in the Brazilian Northern coast. The bioaccumulation factor (BAF), trophic transfer factor (TTF) and biota-sediment-water were used to correlate the contents of chemical elements found in organisms. The sediment, surface water, phytoplankton and pearl oysters chemical composition was analyzed by ICP-OES and ICP-MS. Pearl oysters showed K, Ca, Mg, P, Mn, Fe, Zn, Al, Ba and Pb accumulation, which concentration increase is associated with their diet (phytoplankton). Al concentrations are 14 times higher in pearl oysters (Paxyodon ponderosus), assuming that they are associated with wastewater emissions and with industrialization processes in the area. BAF and BSAF values are 1000 times higher than the metal concentrations in water and bioavailable fraction concentrations. The oyster-phytoplankton trophic transfer factor indicates that P, Ba, Ca, Na, Cd and Zn showed the largest transfers (from 5 to 19). These trophic transfers may be sufficient to cause significant ecotoxicological effects on the region biota.

  8. Adsorption-desorption characteristics of plutonium and americium with sediment particles in the estuarine environment: studies using plutonium-237 and americium-241

    International Nuclear Information System (INIS)

    Murray, C.N.; Fukai, R.

    1975-01-01

    The particle formation of plutonium and americium, their adsorption onto fresh water sediments and the desorption from the sediments in sea water were studied in the Laboratory under simulated river-estuary conditions, using γ-emitting plutonium-237 and americium-241. The results of the experiments show that the particle formation of plutonium depends on its valence states, on pH and on the salinity of the medium. For river water at pH4, some 25%, 20% and 30% of the added 237 Pu was in particulate form, larger than 0.45 μm, for Pu (III), Pu (IV) and Pu (VI), respectively, while 65%, 90% and 50% of the respective valence states was associated with particles at pH 8. In sea water the general pattern remains similar, although Pu (VI) is more soluble in sea water owing to higher ligand concentrations for carbonate and bicarbonate complexes. The pH-dependency of particle formation of Am (III) is more steep than that of plutonium and seems to be influenced by colloidal substances occurring in the experimental media. The adsorption-desorption characteristics of plutonium and americium with the sediment in river water as well as sea water reflect the characteristics of their particle formation, being dependent upon such properties as valence states, the pH and salinity of the medium. A sewage effluent added to the media has small but measurable effects on the adsorption-desorption processes of plutonium. (author)

  9. Sedimentation

    Science.gov (United States)

    Cliff R. Hupp; Michael R. Schening

    2000-01-01

    Sedimentation is arguably the most important water-quality concern in the United States. Sediment trapping is cited frequently as a major function of riverine-forested wetlands, yet little is known about sedimcntation rates at the landscape scale in relation to site parameters, including woody vegetation type, elevation, velocity, and hydraulic connection to the river...

  10. Trace elements in bottom sediments of the Barents Sea on the standard section "Kola Meridian"

    OpenAIRE

    Lapteva A. M.; Plotitsyna N. F.

    2017-01-01

    The levels of trace metals (Cu, Zn, Ni, Cr, Mn, Co, Pb, Cd, Hg) and arsenic (As) in samples of bottom sediments from the Barents Sea on eight stations of the standard section "Kola Meridian" have been investigated. Trace elements have been determined on atomic absorption spectrophotometer AA-6800 with mercury-hydride attachment HVG-1 of the company Shimadzu (Japan) by the methods of flaming (acetylene – air) and electrothermal atomization. Common and very toxic trace elements incl...

  11. Mercury enrichment in sediments of Amba estuary

    Digital Repository Service at National Institute of Oceanography (India)

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

    of anthropogenic metal to the estuary. Geoaccumulation index and enrichment factor support Hg contamination of the estuarine sediment to a varying degree. Hg is not significantly correlated with TOC, Al, Fe and Mn in these sediments...

  12. Needs Assessment for the Use of NASA Remote Sensing Data in the Development and Implementation of Estuarine and Coastal Water Quality Standards

    Science.gov (United States)

    Spiering, Bruce; Underwood, Lauren; Ellis, Chris; Lehrter, John; Hagy, Jim; Schaeffer, Blake

    2010-01-01

    The goals of the project are to provide information from satellite remote sensing to support numeric nutrient criteria development and to determine data processing methods and data quality requirements to support nutrient criteria development and implementation. The approach is to identify water quality indicators that are used by decision makers to assess water quality and that are related to optical properties of the water; to develop remotely sensed data products based on algorithms relating remote sensing imagery to field-based observations of indicator values; to develop methods to assess estuarine water quality, including trends, spatial and temporal variability, and seasonality; and to develop tools to assist in the development and implementation of estuarine and coastal nutrient criteria. Additional slides present process, criteria development, typical data sources and analyses for criteria process, the power of remote sensing data for the process, examples from Pensacola Bay, spatial and temporal variability, pixel matchups, remote sensing validation, remote sensing in coastal waters, requirements for remotely sensed data products, and needs assessment. An additional presentation examines group engagement and information collection. Topics include needs assessment purpose and objectives, understanding water quality decision making, determining information requirements, and next steps.

  13. Investigation of mangrove macroalgae as biomonitors of estuarine metal contamination

    Energy Technology Data Exchange (ETDEWEB)

    Melville, Felicity [Department of Environmental Sciences/Institute of Water and Environmental Resource Management, University of Technology, Sydney, PO Box 123, Broadway NSW 2007 (Australia)], E-mail: f.melville@cqu.edu.au; Pulkownik, Alex [Department of Environmental Sciences/Institute of Water and Environmental Resource Management, University of Technology, Sydney, PO Box 123, Broadway NSW 2007 (Australia)

    2007-11-15

    This study examined the potential use of macroalgae epiphytic on mangrove aerial roots as biomonitors of estuarine contamination. The metal concentrations of macroalgae were investigated in four estuaries in the vicinity of Sydney, Australia, and compared to water and sediment metal concentrations over three seasonal surveys. Macroalgal metal concentrations (copper, zinc, cadmium, chromium, lead, nickel, manganese and iron) appeared to be more associated with sediment metal concentrations than water concentrations, suggesting they may be useful biomonitors of estuarine sediment contamination. Algae in the more contaminated estuaries generally contained higher metal concentrations. However, concentrations of iron, nickel and manganese appeared to be similar in the algae despite the varying sediment concentrations, while accumulation of copper, zinc, lead and chromium appeared to be associated with ambient environmental concentrations. The uptake of metals also varied among the different species, suggesting that algal parameters, such as morphology, may also influence metal uptake and accumulation.

  14. Marine and Estuarine Pollution.

    Science.gov (United States)

    Reish, Donald J.

    1978-01-01

    Presents a literature review of the effects of various pollutants on marine and estuarine organisms, covering publications of 1976-77. This review includes: (1) effects of pesticides, dredging, dumping, sludge, and petroleum hydrocarbons; and (2) diseases and tissue abnormalities. A list of 441 references is also presented. (HM)

  15. Nitrous oxide emissions from estuarine intertidal sediments

    NARCIS (Netherlands)

    Middelburg, J.J.; Klaver, G.; Nieuwenhuize, J.; Markusse, R.M.; Vlug, T.; Nat, F.J.W.A. van der

    1995-01-01

    From September 1990 through December 1991 nitrous oxide flux measurements were made at 9 intertidal mud flat sites in the Scheldt Estuary. Nitrous oxide release rates were highly variable both between sites and over time at any one site. Annual nitrous oxide fluxes vary from about 10 mmol N m-2 at

  16. Multiple scales of suspendend sediment dynamics in a complex geometry estuary

    NARCIS (Netherlands)

    Achete,F.M.

    2016-01-01

    Many estuaries are located in urbanized, highly engineered environments. Cohesive sediment plays an important role because of its affect on estuarine health and ecology. An important ecological parameter is the suspended sediment concentration (SSC) translated into turbidity levels and sediment

  17. Geochronology of the Rio Formoso estuarine by {sup 210}Pb

    Energy Technology Data Exchange (ETDEWEB)

    Arruda, Gilberto N.; Lyra, Denilson T.; Melo, Julyanne T.B.; Farias, Emerson E.G.; Franca, Elvis J.; Santos, Thiago O., E-mail: gnarruda@cnen.gov.br, E-mail: denilsonengseg@gmail.com, E-mail: julyanne.melo@ufpe.br, E-mail: emersonemiliano@yahoo.com.br, E-mail: ejfranca@cnen.gov.br [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil); Souza Neto, Joao A., E-mail: adauto@ufpe.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil)

    2015-07-01

    Uranium series disequilibrium is useful for dating methods, in which profile sediments can be considered as historical records of anthropogenic events regarding the distribution and impacts of chemical substances on the environment. In this study, 2 deep sediment profiles (about 1 m) were collected, layered at each 3 cm, oven-dried and homogenized. The radiochemical separation of {sup 210}Pb consisted of using hydrobromic acid and an ion exchange resin (DOWEX) for precipitating {sup 210}Pb in the form of lead chromate. After 10 days, the radioactivity was therefore measured by means of the low level gas flow proportional counter, model S5-XLB, from Canberra. Sedimentation rate were obtained by CIC (Constant Initial Concentration) model assumes a constant sedimentation rate throughout the period over which unsupported {sup 210}Pb is measurable. Some sediment profiles were not dated since the percentage of sand was quite high in top layers or a high percentage of organic matter and water in excess were observed in the all sediment samples. {sup 210}Pb geochronology was successfully applied to age nine sediment profiles, in which higher sedimentation rates were observed in the middle portion of the estuarine probably related to shrimp farming impacts. By using geochronology, the detection of human impacts on chemical element distribution could be enhanced in the case of environmental monitoring studies in the Rio Formoso estuarine. (author)

  18. Geochronology of the Rio Formoso estuarine by 210Pb

    International Nuclear Information System (INIS)

    Arruda, Gilberto N.; Lyra, Denilson T.; Melo, Julyanne T.B.; Farias, Emerson E.G.; Franca, Elvis J.; Santos, Thiago O.; Souza Neto, Joao A.

    2015-01-01

    Uranium series disequilibrium is useful for dating methods, in which profile sediments can be considered as historical records of anthropogenic events regarding the distribution and impacts of chemical substances on the environment. In this study, 2 deep sediment profiles (about 1 m) were collected, layered at each 3 cm, oven-dried and homogenized. The radiochemical separation of 210 Pb consisted of using hydrobromic acid and an ion exchange resin (DOWEX) for precipitating 210 Pb in the form of lead chromate. After 10 days, the radioactivity was therefore measured by means of the low level gas flow proportional counter, model S5-XLB, from Canberra. Sedimentation rate were obtained by CIC (Constant Initial Concentration) model assumes a constant sedimentation rate throughout the period over which unsupported 210 Pb is measurable. Some sediment profiles were not dated since the percentage of sand was quite high in top layers or a high percentage of organic matter and water in excess were observed in the all sediment samples. 210 Pb geochronology was successfully applied to age nine sediment profiles, in which higher sedimentation rates were observed in the middle portion of the estuarine probably related to shrimp farming impacts. By using geochronology, the detection of human impacts on chemical element distribution could be enhanced in the case of environmental monitoring studies in the Rio Formoso estuarine. (author)

  19. Standard operating procedures for collection of soil and sediment samples for the Sediment-bound Contaminant Resiliency and Response (SCoRR) strategy pilot study

    Science.gov (United States)

    Fisher, Shawn C.; Reilly, Timothy J.; Jones, Daniel K.; Benzel, William M.; Griffin, Dale W.; Loftin, Keith A.; Iwanowicz, Luke R.; Cohl, Jonathan A.

    2015-12-17

    An understanding of the effects on human and ecological health brought by major coastal storms or flooding events is typically limited because of a lack of regionally consistent baseline and trends data in locations proximal to potential contaminant sources and mitigation activities, sensitive ecosystems, and recreational facilities where exposures are probable. In an attempt to close this gap, the U.S. Geological Survey (USGS) has implemented the Sediment-bound Contaminant Resiliency and Response (SCoRR) strategy pilot study to collect regional sediment-quality data prior to and in response to future coastal storms. The standard operating procedure (SOP) detailed in this document serves as the sample-collection protocol for the SCoRR strategy by providing step-by-step instructions for site preparation, sample collection and processing, and shipping of soil and surficial sediment (for example, bed sediment, marsh sediment, or beach material). The objectives of the SCoRR strategy pilot study are (1) to create a baseline of soil-, sand-, marsh sediment-, and bed-sediment-quality data from sites located in the coastal counties from Maine to Virginia based on their potential risk of being contaminated in the event of a major coastal storm or flooding (defined as Resiliency mode); and (2) respond to major coastal storms and flooding by reoccupying select baseline sites and sampling within days of the event (defined as Response mode). For both modes, samples are collected in a consistent manner to minimize bias and maximize quality control by ensuring that all sampling personnel across the region collect, document, and process soil and sediment samples following the procedures outlined in this SOP. Samples are analyzed using four USGS-developed screening methods—inorganic geochemistry, organic geochemistry, pathogens, and biological assays—which are also outlined in this SOP. Because the SCoRR strategy employs a multi-metric approach for sample analyses, this

  20. Predicting the Spatial Distribution of Organic Contaminants in an Estuarine System using a Random Forest Approach

    Science.gov (United States)

    Modeling the magnitude and distribution of estuarine sediment contamination by pollutants of historic (e.g. PCB) and emerging concern (e.g., personal care products, PCP) is often limited by incomplete site knowledge and inadequate sediment contamination sampling. We tested a mode...

  1. Spatial and seasonal variability of trace-element concentrations in sediments from the Santos-Cubatao estuarine system, Sao Paulo, Brazil; Variabilidade espacial e sazonal da concentracao de elementos-traco em sedimentos do sistema estuarino de Santos-Cubatao (SP)

    Energy Technology Data Exchange (ETDEWEB)

    Luiz-Silva, Wanilson [Universidade Estadual de Campinas, SP (Brazil). Inst. de Geociencias]. E-mail: wanilson@ige.unicamp.br; Matos, Rosa Helena Ribeiro; Kristosch, Giane Chaves [UNESP, Rio Claro, SP (Brazil). Dept. de Zoologia; Machado, Wilson [Universidade Federal Fluminense, Niteroi, RJ (Brazil). Inst. de Geoquimica

    2006-03-15

    Multi-element analyses of sediment samples from the Santos-Cubatao Estuarine System were carried out to investigate the spatial and seasonal variability of trace-element concentrations. The study area contains a rich mangrove ecosystem that is a habitat for tens of thousands of resident and migratory bi some of them endangered globally. Enrichments of metals in fine-grained surface sediments are, in decreasing order, Hg, Mn, La, Ca, Sr, Cd, Zn, Pb, Ba, Cu, Cr, Fe, Nb, Y, Ni and Ga, relative to pre-industrial background levels. The maximum enrichment ranged from 49 (Hg) to 3.1 (Ga). Mercury concentrations were greater in the Cubatao river than in other sites, while the other elements showed greater concentrations in the Morrao river. Concentrations of Mn were significantly greater in winter and autumn than in summer and spring. However, other elements (e.g. Cd and Pb) showed the opposite, with greater concentrations in summer and spring. This study suggests that seasonal changes in physical and chemical conditions may affect the degree of sediment enrichment and therefore make the assessment of contamination difficult. Consequently, these processes need to be considered when assessing water quality and the potential contamination of biota.(author)

  2. The dirt on sediments

    Science.gov (United States)

    Smith, Loren M.; Euliss, Ned H. "Chip"

    2010-01-01

    In the wetland science field, sediment deposition is often thought of as being beneficial especially when one thinks of coastal estuarine systems. For example, sediments deposited from streams and rivers are necessary to naturally build and maintain tidal marshes. These sediments come from eroded upland soils in the interior of the continent. When these sediments are diverted from natural coastal deposition areas, such as occurs from river channelization, we lose marshes through subsidence as is happening throughout coastal Louisiana. However, the value of eroded soils is all a matter of hydrogeomorphic perspective.

  3. Metal Bioaccumulation by Estuarine Food Webs in New England, USA

    Directory of Open Access Journals (Sweden)

    Celia Y. Chen

    2016-06-01

    Full Text Available Evaluating the degree of metal exposure and bioaccumulation in estuarine organisms is important for understanding the fate of metals in estuarine food webs. We investigated the bioaccumulation of Hg, methylmercury (MeHg, Cd, Se, Pb, and As in common intertidal organisms across a watershed urbanization gradient of coastal marsh sites in New England to relate metal exposure and bioaccumulation in fauna to both chemical and ecological factors. In sediments, we measured metal and metalloid concentrations, total organic carbon (TOC and SEM-AVS (Simultaneously extracted metal-acid volatile sulfides. In five different functional feeding groups of biota, we measured metal concentrations and delta 15N and delta 13C signatures. Concentrations of Hg and Se in biota for all sites were always greater than sediment concentrations whereas Pb in biota was always lower. There were positive relationships between biota Hg concentrations and sediment concentrations, and between biota MeHg concentrations and both pelagic feeding mode and trophic level. Bioavailability of all metals measured as SEM-AVS or Benthic-Sediment Accumulation Factor was lower in more contaminated sites, likely due to biogeochemical factors related to higher levels of sulfides and organic carbon in the sediments. Our study demonstrates that for most metals and metalloids, bioaccumulation is metal specific and not directly related to sediment concentrations or measures of bioavailability such as AVS-SEM.

  4. Benthic infaunal community structuring in an acidified tropical estuarine system.

    Science.gov (United States)

    Hossain, M Belal; Marshall, David J

    2014-01-01

    Recent studies suggest that increasing ocean acidification (OA) should have strong direct and indirect influences on marine invertebrates. While most theory and application for OA is based on relatively physically-stable oceanic ecological systems, less is known about the effects of acidification on nearshore and estuarine systems. Here, we investigated the structuring of a benthic infaunal community in a tropical estuarine system, along a steep salinity and pH gradient, arising largely from acid-sulphate groundwater inflows (Sungai Brunei Estuary, Borneo, July 2011- June 2012). Preliminary data indicate that sediment pore-water salinity (range: 8.07 - 29.6 psu) declined towards the mainland in correspondence with the above-sediment estuarine water salinity (range: 3.58 - 31.2 psu), whereas the pore-water pH (range: 6.47- 7.72) was generally lower and less variable than the estuarine water pH (range: 5.78- 8.3), along the estuary. Of the thirty six species (taxa) recorded, the polychaetes Neanthes sp., Onuphis conchylega, Nereididae sp. and the amphipod Corophiidae sp., were numerically dominant. Calcified microcrustaceans (e.g., Cyclopoida sp. and Corophiidae sp.) were abundant at all stations and there was no clear distinction in distribution pattern along the estuarine between calcified and non-calcified groups. Species richness increased seawards, though abundance (density) showed no distinct directional trend. Diversity indices were generally positively correlated (Spearman's rank correlation) with salinity and pH (p 0.05). Three faunistic assemblages were distinguished: (1) nereid-cyclopoid-sabellid, (2) corophiid-capitellid and (3) onuphid- nereid-capitellid. These respectively associated with lower salinity/pH and a muddy bottom, low salinity/pH and a sandy bottom, and high salinity/pH and a sandy bottom. However, CCA suggested that species distribution and community structuring is more strongly influenced by sediment particle characteristics than by the

  5. Growth Characteristics of an Estuarine Heterocystous Cyanobacterium

    Directory of Open Access Journals (Sweden)

    Pablo Guimarães

    2017-06-01

    Full Text Available A new estuarine filamentous heterocystous cyanobacterium was isolated from intertidal sediment of the Lagoa dos Patos estuary (Brazil. The isolate may represent a new genus related to Cylindrospermopsis. While the latter is planktonic, contains gas vesicles, and is toxic, the newly isolated strain is benthic and does not contain gas vesicles. It is not known whether the new strain is toxic. It grows equally well in freshwater, brackish and full salinity growth media, in the absence of inorganic or organic combined nitrogen, with a growth rate 0.6 d-1. Nitrogenase, the enzyme complex responsible for fixing dinitrogen, was most active during the initial growth phase and its activity was not different between the different salinities tested (freshwater, brackish, and full salinity seawater. Salinity shock also did not affect nitrogenase activity. The frequency of heterocysts was high, coinciding with high nitrogenase activity during the initial growth phase, but decreased subsequently. However, the frequency of heterocysts decreased considerably more at higher salinity, while no change in nitrogenase activity occurred, indicating a higher efficiency of dinitrogen fixation. Akinete frequency was low in the initial growth phase and higher in the late growth phase. Akinete frequency was much lower at high salinity, which might indicate better growth conditions or that akinete differentiation was under the same control as heterocyst differentiation. These trends have hitherto not been reported for heterocystous cyanobacteria but they seem to be well fitted for an estuarine life style.

  6. Winnowing and Flocculation in Bio-physical Cohesive Substrate: A Flume Experimental and Estuarine Study

    Science.gov (United States)

    Ye, L.; Parsons, D. R.; Manning, A. J.

    2016-12-01

    Cohesive sediment, or mud, is ubiquitously found in most aqueous environments, such as coasts and estuaries. The study of cohesive sediment behaviors requires the synchronous description of mutual interactions of grains (e.g., winnowing and flocculation), their physical properties (e.g., grain size) and also the ambient water. Herein, a series of flume experiments (14 runs) with different substrate mixtures of sand-clay-EPS (Extracellular Polymeric Substrates: secreted by aquatic microorganisms) are combined with an estuarine field survey (Dee estuary, NW England) to investigate the behavior of suspensions over bio-physical cohesive substrates. The experimental results indicate that winnowing and flocculation occur pervasively in bio-physical cohesive flow systems. Importantly however, the evolution of the bed and bedform dynamics and hence turbulence production can be lower when cohesivity is high. The estuarine survey also revealed that the bio-physical cohesion provided by both the clay and microorganism fractions in the bed, that pervasively exists in many natural estuarine systems, plays a significant role in controlling the interactions between bed substrate and sediment suspension and deposition, including controlling processes such as sediment winnowing, flocculation and re-deposition. Full understanding of these processes are essential in advancing sediment transport modelling and prediction studies across natural estuarine systems and the work will report on an improved conceptual model for sediment sorting deposition in bio-physical cohesive substrates.

  7. Maximum standard metabolic rate corresponds with the salinity of maximum growth in hatchlings of the estuarine northern diamondback terrapin (Malaclemys terrapin terrapin): Implications for habitat conservation

    Science.gov (United States)

    Rowe, Christopher L.

    2018-01-01

    I evaluated standard metabolic rates (SMR) of hatchling northern diamondback terrapins (Malaclemys terrapin terrapin) across a range of salinities (salinity = 1.5, 4, 8, 12, and 16 psu) that they may encounter in brackish habitats such as those in the Maryland portion of the Chesapeake Bay, U.S.A. Consumption of O2 and production of CO2 by resting, unfed animals served as estimates of SMR. A peak in SMR occurred at 8 psu which corresponds closely with the salinity at which hatchling growth was previously shown to be maximized (salinity ∼ 9 psu). It appears that SMR is influenced by growth, perhaps reflecting investments in catabolic pathways that fuel anabolism. This ecophysiological information can inform environmental conservation and management activities by identifying portions of the estuary that are bioenergetically optimal for growth of hatchling terrapins. I suggest that conservation and restoration efforts to protect terrapin populations in oligo-to mesohaline habitats should prioritize protection or creation of habitats in regions where average salinity is near 8 psu and energetic investments in growth appear to be maximized.

  8. Standard metabolic rates of early life stages of the diamondback terrapin (Malaclemys terrapin), an estuarine turtle, suggest correlates between life history changes and the metabolic economy of hatchlings.

    Science.gov (United States)

    Rowe, Christopher L

    2018-04-01

    I estimated standard metabolic rates (SMR) using measurements of oxygen consumption rates of embryos and unfed, resting hatchlings of the diamondback terrapin (Malaclemys terrapin) three times during embryonic development and twice during the early post-hatching period. The highest observed SMRs occurred during mid to late embryonic development and the early post-hatching period when hatchlings were still reliant on yolk reserves provided by the mother. Hatchlings that were reliant on yolk displayed per capita SMR 135 % higher than when measured 25 calendar days later after they became reliant on exogenous resources. The magnitude of the difference in hatchling SMR between yolk-reliant and exogenously feeding stages was much greater than that attributed to costs of digestion (specific dynamic action) observed in another emydid turtle, suggesting that processing of the yolk was not solely responsible for the observed difference. The pre-feeding period of yolk reliance of hatchlings corresponds with the period of dispersal from the nesting site, suggesting that elevated SMR during this period could facilitate dispersal activities. Thus, I hypothesize that the reduction in SMR after the development of feeding behaviors may reflect an energy optimization strategy in which a high metabolic expenditure in support of development and growth of the embryo and dispersal of the hatchling is followed by a substantial reduction in metabolic expenditure coincident with the individual becoming reliant on exogenous resources following yolk depletion. Copyright © 2018 Elsevier GmbH. All rights reserved.

  9. Shortened screening method for phosphorus fractionation in sediments A complementary approach to the standards, measurements and testing harmonised protocol

    International Nuclear Information System (INIS)

    Pardo, Patricia; Rauret, Gemma; Lopez-Sanchez, Jose Fermin

    2004-01-01

    The SMT protocol, a sediment phosphorus fractionation method harmonised and validated in the frame of the standards, measurements and testing (SMT) programme (European Commission), establishes five fractions of phosphorus according to their extractability. The determination of phosphate extracted is carried out spectrophotometrically. This protocol has been applied to 11 sediments of different origin and characteristics and the phosphorus extracted in each fraction was determined not only by UV-Vis spectrophotometry, but also by inductively coupled plasma-atomic emission spectrometry. The use of these two determination techniques allowed the differentiation between phosphorus that was present in the extracts as soluble reactive phosphorus and as total phosphorus. From the comparison of data obtained with both determination techniques a shortened screening method, for a quick evaluation of the magnitude and importance of the fractions given by the SMT protocol, is proposed and validated using two certified reference materials

  10. The use of mechanistic descriptions of algal growth and zooplankton grazing in an estuarine eutrophication model

    Science.gov (United States)

    Baird, M. E.; Walker, S. J.; Wallace, B. B.; Webster, I. T.; Parslow, J. S.

    2003-03-01

    A simple model of estuarine eutrophication is built on biomechanical (or mechanistic) descriptions of a number of the key ecological processes in estuaries. Mechanistically described processes include the nutrient uptake and light capture of planktonic and benthic autotrophs, and the encounter rates of planktonic predators and prey. Other more complex processes, such as sediment biogeochemistry, detrital processes and phosphate dynamics, are modelled using empirical descriptions from the Port Phillip Bay Environmental Study (PPBES) ecological model. A comparison is made between the mechanistically determined rates of ecological processes and the analogous empirically determined rates in the PPBES ecological model. The rates generally agree, with a few significant exceptions. Model simulations were run at a range of estuarine depths and nutrient loads, with outputs presented as the annually averaged biomass of autotrophs. The simulations followed a simple conceptual model of eutrophication, suggesting a simple biomechanical understanding of estuarine processes can provide a predictive tool for ecological processes in a wide range of estuarine ecosystems.

  11. Determination of multi-element composition of Vietnamese marine sediment and tuna fish by k0-standardized neutron activation analysis

    International Nuclear Information System (INIS)

    Manh-Dung Ho; Quang-Thien Tran; Van-Doanh Ho; Thi-Sy Nguyen

    2016-01-01

    The k 0 -standardized neutron activation analysis (k 0 -NAA) has been applied for determination of multiple elements (25 elements: Al, As, Ba, Br, Ca, Cl, Co, Cr, Cs, Cu, Eu, Fe, Hg, K, La, Mg, Na, Rb, Sc, Se, Sm, Th, Ti, V and Zn) in marine sediment and tuna fish. About 50 marine sediment and 9 tuna fish samples were collected in two coastal areas of Vietnam. The health risk index (HRI) values of As and Br were higher than 1.0 for the tuna fish. Also, HRI value of Hg was 8.92 × 10 -1 indicating a relatively high potential health risk, whiles Co and Mn with HRIs = 1.56 × 10 -4 and 8.56 × 10 -4 , respectively, have the lowest potential health risks. Average enrichment factors using Al as a reference element (EF Al ) were higher than 1.5 for Eu, La, Zn, Th, Cs and As in which the highest EF Al value for As was higher than 10. This study showed that the HRI value of As in the tuna fish correlated positively with the EF Al value for the element in the marine sediment. (author)

  12. Determination of polychlorinated dibenzo-p-dioxin and dibenzofuran congeners in air particulate and marine sediment standard reference materials (SRMs).

    Science.gov (United States)

    Chiu, C H; Turle, R; Poole, G; Thibert, B; Brubaker, W W; Schantz, M M; Wise, S A

    2001-02-01

    Due to the limited number of environmental matrix certified reference materials (CRMs) with assigned values for natural levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), an interlaboratory study was undertaken by the National Institute of Standards and Technology (NIST) and Environment Canada to establish reference concentration values for selected PCDD/Fs in two well-characterized NIST Standard Reference Materials (SRMs): SRM 1649a (Urban Dust) and SRM 1944 (New York/New Jersey Waterway Sediment). Results from 14 laboratories were used to provide reference values for the seventeen 2, 3, 7, 8-substituted PCDD/F congeners, the totals for individual tetra- through hepta-substituted PCDD/F homologues, and the total amount of tetra- through hepta-substituted PCDD/Fs. The mass fractions for the individual 2, 3, 7, 8-substituted congeners range from approximately 0.01 microg/kg to 7 microg/kg dry mass.

  13. Three-dimensional semi-idealized model for estuarine turbidity maxima in tidally dominated estuaries

    NARCIS (Netherlands)

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

    2017-01-01

    We develop a three-dimensional idealized model that is specifically aimed at gaining insight in the physical mechanisms resulting in the formation of estuarine turbidity maxima in tidally dominated estuaries. First, the three-dimensional equations for water motion and suspended sediment

  14. How tides and river flows determine estuarine bathymetries [review article

    Science.gov (United States)

    Prandle, D.

    2004-04-01

    For strongly tidal, funnel-shaped estuaries, we examine how tides and river flows determine size and shape. We also consider how long it takes for bathymetric adjustment, both to determine whether present-day bathymetry reflects prevailing forcing and how rapidly changes might occur under future forcing scenarios. Starting with the assumption of a 'synchronous' estuary (i.e., where the sea surface slope resulting from the axial gradient in phase of tidal elevation significantly exceeds the gradient in tidal amplitude ζ̂), an expression is derived for the slope of the sea bed. Thence, by integration we derive expressions for the axial depth profile and estuarine length, L, as a function of ζ̂ and D, the prescribed depth at the mouth. Calculated values of L are broadly consistent with observations. The synchronous estuary approach enables a number of dynamical parameters to be directly calculated and conveniently illustrated as functions of ζ̂ and D, namely: current amplitude Û, ratio of friction to inertia terms, estuarine length, stratification, saline intrusion length, flushing time, mean suspended sediment concentration and sediment in-fill times. Four separate derivations for the length of saline intrusion, LI, all indicate a dependency on D 2/f ÛU o ( Uo is the residual river flow velocity and f is the bed friction coefficient). Likely bathymetries for `mixed' estuaries can be delineated by mapping, against ζ̂ and D, the conditions LI/ Lsalt. By combining the derived expressions for L and LI with this latter criterion, an expression is derived relating Di, the depth at the centre of the intrusion, to the corresponding value of Uo. This expression indicates Uo is always close to 1 cm s -1, as commonly observed. Converting from Uo to river flow, Q, provides a morphological expression linking estuarine depth to Q (with a small dependence on side slope gradients). These dynamical solutions are coupled with further generalised theory related to depth and

  15. General assessment of estuarine pollution

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. General assessment of estuarine pollution. Contamination of estuaries by untreated domestic wastewater is widespread, however, in absence of time-series studies the responses of native flora and fauna to modified environment are unclear. Agricultural runoff ...

  16. Studies on sup(226) Ra and sup(210) Pb activities and the concentration factors of sup(226) Ra in the surface organic layers of the estuarine sediments of Mindola and Purna rivers in India

    Digital Repository Service at National Institute of Oceanography (India)

    Joshi, L.U.; Zingde, M.D.; Desai, B.N.

    ., to the sediment floor The activities of sup(226) Ra are found to vary from 0.1 to 0.5 pCi/g, while sup(210) Pb activities lie in the range of 3 to 8 pCi/g These activities find their way into the organisms present in sea water and then into fish which is finally...

  17. Microbial dehalogenation of organohalides in marine and estuarine environments.

    Science.gov (United States)

    Zanaroli, Giulio; Negroni, Andrea; Häggblom, Max M; Fava, Fabio

    2015-06-01

    Marine sediments are the ultimate sink and a major entry way into the food chain for many highly halogenated and strongly hydrophobic organic pollutants, such as polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), polybrominated diphenylethers (PBDEs) and 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT). Microbial reductive dehalogenation in anaerobic sediments can transform these contaminants into less toxic and more easily biodegradable products. Although little is still known about the diversity of respiratory dehalogenating bacteria and their catabolic genes in marine habitats, the occurrence of dehalogenation under actual site conditions has been reported. This suggests that the activity of dehalogenating microbes may contribute, if properly stimulated, to the in situ bioremediation of marine and estuarine contaminated sediments. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. A kinetic model that explains the dependence of magnetic susceptibility of sediment on grain size and organic matter content in transitional marine environments. Testing case studies in estuarine-like environments of NW Iberia

    Science.gov (United States)

    Rey, D.; Mohamed, K. J.; Andrade, A.; Rubio, B.; Bernabeu, A. M.

    2017-12-01

    The wide use of magnetic proxies to study pollution, sedimentological processes, and environmental and paleoclimatic changes is currently limited by the lack of transference functions that closely correlate with the unmeasurable variables. Among them, magnetic susceptibility (MS) is the oldest and most popular, but have yet to live up to its expectations. This paper explores and quantifies how MS values of surficial sediments in transitional environments depends on grain size and on what can be said about the spatial distribution of hydrodynamic forces and the potential modulation of MS by sediment and organic matter provenances. The concentration of (oxyhydr)oxides in sands (d50 > 63 microns) is primarily controlled by their degree of dilution in the diamagnetic framework, which is larger for coarser grainsizes. In contrast, the concentration of (oxyhydr)oxides in muddy sediments is controlled by their dissolution rate during very early diagenesis, which is controlled by their content in organic matter (TOC), inversely dependent of grainsize. The balance between both components results in the study area in sands of d50 = 68 microns displaying the maximum MS values. The influence of organic matter on the dissolution of magnetite in surficial sediments can be quantified using a simple kinetic model. The model reveals the existence of a negative exponential relationship between magnetic susceptibility and grain size, that depends on the TOC of the fine-grained fraction. The model accurately predicts that a TOC increase of 0.35% results in a 50% reduction in the concentration of magnetite in the sediments of the Ría the Muros. We have also encountered this relationship not universal in this form, as its quantification is strongly modulated by coarse sediment mineralogy, TOC lability and by other factors such as wave climate, depth, and sediment oxygenation. Better understanding and quantification of the role that TOC, hydrodynamics, and changes in the geochemical

  19. Ability of salt marsh plants for TBT remediation in sediments

    OpenAIRE

    Carvalho, P. N.; Basto, M. C.; Moreira da Silva, M.; Machado, A.; Bordalo, A.; Vasconcelos, M. T.

    2010-01-01

    The capability of Halimione portulacoides, Spartina maritima, and Sarcocornia fruticosa (halophytes very commonly found in salt marshes from Mediterranean areas) for enhancing remediation of tributyltin (TBT) from estuarine sediments was investigated, using different experimental conditions.

  20. Reductive Dechlorination of Polychlorinated Biphenyls in Marine Sediments

    National Research Council Canada - National Science Library

    Sowers, Kevin

    1999-01-01

    ... Community by Comparative Sequence Analysis of Genes Coding for 16S rRNA, Microbial Reductive Dechlorination of Aroclor 1260 in Anaerobic Slurries of Estuarine Sediments, Differential RFLP patterns of PCR...

  1. Sediments of a retting yard

    Digital Repository Service at National Institute of Oceanography (India)

    Remani, K.N.; Venugopal, P.; Devi, K.S.; Unnithan, R.V.

    (av. 46.8 and 92.3 mg/g respectively) compared to the reference station (20.6 and 48.9 mg/g) and published data on estuarine sediments.C/N ratios were consistently higher in the retting yard. Organic nitrogen, however,did not show this trend. Annual...

  2. Benthic and pelagic pathways of methylmercury bioaccumulation in estuarine food webs of the northeast United States.

    Directory of Open Access Journals (Sweden)

    Celia Y Chen

    Full Text Available Methylmercury (MeHg is a contaminant of global concern that bioaccumulates and bioamagnifies in marine food webs. Lower trophic level fauna are important conduits of MeHg from sediment and water to estuarine and coastal fish harvested for human consumption. However, the sources and pathways of MeHg to these coastal fisheries are poorly known particularly the potential for transfer of MeHg from the sediment to biotic compartments. Across a broad gradient of human land impacts, we analyzed MeHg concentrations in food webs at ten estuarine sites in the Northeast US (from the Hackensack Meadowlands, NJ to the Gulf of Maine. MeHg concentrations in water column particulate material, but not in sediments, were predictive of MeHg concentrations in fish (killifish and Atlantic silversides. Moreover, MeHg concentrations were higher in pelagic fauna than in benthic-feeding fauna suggesting that MeHg delivery to the water column from methylation sites from within or outside of the estuary may be an important driver of MeHg bioaccumulation in estuarine pelagic food webs. In contrast, bulk sediment MeHg concentrations were only predictive of concentrations of MeHg in the infaunal worms. Our results across a broad gradient of sites demonstrate that the pathways of MeHg to lower trophic level estuarine organisms are distinctly different between benthic deposit feeders and forage fish. Thus, even in systems with contaminated sediments, transfer of MeHg into estuarine food webs maybe driven more by the efficiency of processes that determine MeHg input and bioavailability in the water column.

  3. Incorporating Contaminant Bioavailability into Sediment Quality Assessment Frameworks

    Science.gov (United States)

    The recently adopted sediment quality assessment framework for evaluating bay and estuarine sediments in the State of California incorporates bulk sediment chemistry as a key line of evidence(LOE) but does not address the bioavailability of measured contaminants. Thus, the chemis...

  4. EFFECT OF CONTAMINANT AND ORGANIC MATTER BIOAVAILABILITY ON THE MICROBIAL DEHALOGENATION OF SEDIMENT-BOUND CHLOROBENZENES. (R825513C007)

    Science.gov (United States)

    The extent of reductive dechlorination occurring in contaminated, estuarine sediments was investigated. Contaminant and organic matter bioavailability and their effect on the reductive dechlorination of sediment-bound chlorobenzenes was the main focus of the work presented her...

  5. Fine sediment transport into the hyperturbid lower Ems River : The role of channel deepening and sediment-induced drag reduction

    NARCIS (Netherlands)

    Van Maren, D.S.; Winterwerp, J.C.; Vroom, J.

    2015-01-01

    Deepening of estuarine tidal channels often leads to tidal amplification and increasing fine sediment import. Increasing fine sediment import, in turn, may lower the hydraulic drag (due to a smoother muddy bed and/or sediment-induced damping of turbulence), and therefore, further strengthen tidal

  6. Fundamentals of estuarine physical oceanography

    CERN Document Server

    Bruner de Miranda, Luiz; Kjerfve, Björn; Castro Filho, Belmiro Mendes de

    2017-01-01

    This book provides an introduction to the complex system functions, variability and human interference in ecosystem between the continent and the ocean. It focuses on circulation, transport and mixing of estuarine and coastal water masses, which is ultimately related to an understanding of the hydrographic and hydrodynamic characteristics (salinity, temperature, density and circulation), mixing processes (advection and diffusion), transport timescales such as the residence time and the exposure time. In the area of physical oceanography, experiments using these water bodies as a natural laboratory and interpreting their circulation and mixing processes using theoretical and semi-theoretical knowledge are of fundamental importance. Small-scale physical models may also be used together with analytical and numerical models. The book highlights the fact that research and theory are interactive, and the results provide the fundamentals for the development of the estuarine research.

  7. Mobilization of radionuclides from sediments. Potential sources to Arctic waters

    International Nuclear Information System (INIS)

    Oughton, D.H.; Boerretzen, P.; Mathisen, B.; Salbu, B.; Tronstad, E.

    1995-01-01

    Contaminated soils and sediments can act as secondary sources of radionuclides to Arctic waters. In cases where the original source of contamination has ceased or been greatly reduced (e.g., weapons' testing, waste discharges from Mayak and Sellafield) remobilization of radionuclides from preciously contaminated sediments increases in importance. With respect to Arctic waters, potential secondary sources include sediments contaminated by weapons' testing, by discharges from nuclear installations to seawater, e.g., the Irish Sea, or by leakages from dumped waste containers. The major land-based source is run-off from soils and transport from sediments in the catchment areas of the Ob and Yenisey rivers, including those contaminated by Mayak discharges. Remobilization of radionuclides is often described as a secondary source of contamination. Whereas primary sources of man-made radionuclides tend to be point sources, secondary sources are usually more diffuse. Experiments were carried out on marine (Kara Sea, Irish Sea, Stepovogo and Abrosimov Fjords), estuarine (Ob-Yenisey) and dirty ice sediments. Total 137 Cs and 90 Sr concentrations were determined using standard radiochemical techniques. Tracer studies using 134 Cs and 85 Sr were used to investigate the kinetics of radionuclide adsorption and desorption. It is concluded that 90 Sr is much less strongly bound to marine sediments than 137 Cs, and can be chemically mobilized through ion exchange with elements is seawater. Radiocaesium is strongly and rapidly fixed to sediments. Discharges of 137 Cs to surface sediments (i.e., from dumped containers) would be expected to be retained in sediments to a greater extent than discharges to sea-waters. Physical mobilization of sediments, for example resuspension, may be of more importance for transport of 137 Cs than for 90 Sr. 7 refs., 4 figs

  8. Metal and trace element sediment assessment from two estuarine systems: Santos/Sao Vicente and Cananeia, State of Sao Paulo, Brazil; Avaliacao da concentracao de metais e outros elementos de interesse em amostras de sedimentos dos estuarios de Santos/Sao Vicente e Cananeia, estado de Sao Paulo, Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Amorim, Eduardo Paulo de

    2012-07-01

    This study evaluated some toxic metals such as Cd, Hg and Pb and some other major and trace elements in surface sediment samples, from two different systems under different degrees of anthropogenic actions: the estuarine system of Santos/Sao Vicente and the southern part of the Cananeia estuary, both on the Sao Paulo state coast. Sediment samples were collected in 16 stations in the Santos/Sao Vicente estuary and 13 stations in the Cananeia estuary, during summer and winter of 2005 and 2006, in both estuaries. Three analytical techniques were used: NAA, AAS and ICP OES. NAA was used for the quantification of major element concentration levels (Ca, Fe and Na), trace elements (As, Ba, Br, Cd, Co, Cu, Cr, Cs, Hf, Rb, Sb, Sc, Se, Ta, Th, U, and Zn and rare earths elements La, Ce, Eu, Nd, Sm, Lu, Tb, Yb). ICP OES was used for determination of the concentration levels of Al, Ba, Be, Bi, B, Cd, Co, Pb, Cu, Cr, Sn, Sr, Fe, Li, Mn, Mo, Ni, Tl, Ti, V and Zn. AAS for Cd and Pb quantification through graphite furnace (GF AAS) and Hg through cold vapor generation (CV AAS). Methodology validation according to precision and accuracy was performed by reference material analyses for the three analytical techniques used. Detection and quantification limits were calculated for each element evaluated. Seasonal variations (summer and winter), spatial and temporal (2005 e 2006) variations of metals and trace elements were also evaluated. In the Santos estuary, in general, metal and trace element concentrations , organic matter content and % of pelitic fraction found in the Santos channel (area 1) were higher than those of the Santos Bay (area 2) and Sao Vicente channel (area 3). Area 1 suffers high impact from industrial activities from the Cubatao region and Santos port. The sediments from station 14 (area 3, Sao Vicente channel), showed the same behavior of those from area 1, suffering influence from the industrial pole and located in a mangrove area. In comparison with TEL and PEL

  9. Suspended matter and bottom deposits in the Mahury estuarine system (French Guiana): Environmental consequences

    Science.gov (United States)

    Jouanneau, J. M.; Pujos, M.

    As part of a study carried out on the major rivers in French Guiana to identify and estimate the respective share of local rivers in the sedimentation of estuaries and the inshore continental shelf, results are reported on the Mahury after 2 periods of fieldwork carried out during one dry and one rainy season. The specific characteristics of the whole Mahury fluvio-estuarine system can be summed up as follows: the sands have invariable annual characteristics; they show evidence of a long history, first marine, then continental and finally fluviatile. They play little part in sedimentation on the continental shelf, and what part they do play is limited to the beaches. The fine sediments too have invariable annual characteristics. They fall, if we consider their mineralogical and elemental composition, on either side of a limit separating the fluviatile and estuarine zones. Here, the sediment stocks are respectively authigenic and allothogenic, while the clay association and elemental composition in the latter zone are evidence of an Amazonian origin. The contribution of the Mahury (Comté-Orapu) to fine estuarine sedimentation thus appears at present to be a very limited one, the Amazon being predominant over vast coastal areas, including the French Guiana estuaries.

  10. Late Holocene palynological record and landscape change from the Piraquê-Açu and Piraquê-Mirím estuarine system, Espírito Santo, Brazil

    Directory of Open Access Journals (Sweden)

    ALEX DA SILVA FREITAS

    2016-04-01

    Full Text Available The Piraquê-Açu and Piraquê-Mirim estuarine system (PAPMES is located next to the Aracruz City (19˚ 57' S and 40˚ 9' W, Espírito Santo State, Brazil. Palynological analyses were conducted based on two sediment cores (PA20 and PM1. The main purpose of the present study was to recognize and interpret the vegetation dynamics in the region around the collection site in the last 2000 cal yrs BP. The sediment cores were subsampled at each 10 cm depth. The samples were submitted to standard palynological processes. The PA20 sediment core obtained the oldest age of 1758±68 cal yrs BP at a depth of approximately 105-cm. However, the PM1 sediment core obtained the oldest age of ≈2071±82 cal yrs BP at a depth of 95-cm. The comparative record of the sediment cores demonstrated that palynomorphs deposition were directly influenced by local water circulation. Pollen analysis indicated the striking presence of mangrove vegetation, which is mainly characterised by the Rhizophora pollen type. The other vegetation communities underwent little variation over the studied period. The top sediment layers of both sediment cores are characterized by the presence of exotic pollen grains of Eucalyptus, introduced by humans, and by the decrease of the original vegetation.

  11. Relationship between the lability of sediment-bound Cd and its bioaccumulation in edible oyster.

    Science.gov (United States)

    Chakraborty, Parthasarathi; Ramteke, Darwin; Chakraborty, Sucharita; Chennuri, Kartheek; Bardhan, Pratirupa

    2015-11-15

    A linkage between Cd speciation in sediments and its bioaccumulation in edible oyster (Crassostrea sp.) from a tropical estuarine system was established. Bioaccumulation of Cd in edible oyster increased with the increasing lability and dissociation rate constants of Cd-sediment complexes in the bottom sediments. Total Cd concentration in sediment was not a good indicator of Cd-bioavailability. Increasing trace metal competition in sediments increased lability and bioavailability of Cd in the tropical estuarine sediment. Low thermodynamic stability and high bioavailability of Cd in the estuarine sediment were responsible for high bioaccumulation of Cd in edible oysters (3.2-12.2mgkg(-1)) even though the total concentration of Cd in the bottom sediment was low (0.17-0.49mgkg(-1)). Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Heavy metal concentration in mangrove surface sediments from the north-west coast of South America.

    Science.gov (United States)

    Fernández-Cadena, J C; Andrade, S; Silva-Coello, C L; De la Iglesia, R

    2014-05-15

    Mangrove ecosystems are coastal estuarine systems confined to the tropical and subtropical regions. The Estero Salado mangrove located in Guayaquil, Ecuador, has suffered constant disturbances during the past 20 years, due to industrial wastewater release. However, there are no published data for heavy metals present in its sediments and the relationship with anthropogenic disturbance. In the present study, metal concentrations were evaluated in surface sediment samples of the mangrove, showing that B, Cd, Cu, Pb, Se, V, and Zn levels exceeded those declared in international environmental quality standards. Moreover, several metals (Pb, Sn, Cd, Ag, Mo, Zn and Ni) could be linked to the industrial wastewater present in the studied area. In addition, heavy metal levels detected in this mangrove are higher than previous reports on mangrove sediments worldwide, indicating that this mangrove ecosystem is one of the most disrupted on earth. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Assessing estuarine quality: A cost-effective in situ assay with amphipods.

    Science.gov (United States)

    Martinez-Haro, Monica; Acevedo, Pelayo; Pais-Costa, Antónia Juliana; Taggart, Mark A; Martins, Irene; Ribeiro, Rui; Marques, João Carlos

    2016-05-01

    In situ assays based on feeding depression can be powerful ecotoxicological tools that can link physiological organism-level responses to population and/or community-level effects. Amphipods are traditional target species for toxicity tests due to their high sensitivity to contaminants, availability in the field and ease of handling. However, cost-effective in situ assays based on feeding depression are not yet available for amphipods that inhabit estuarine ecosystems. The aim of this work was to assess a short-term in situ assay based on postexposure feeding rates on easily quantifiable food items with an estuarine amphipod. Experiments were carried out under laboratory conditions using juvenile Echinogammarus marinus as the target individual. When 60 Artemia franciscana nauplii (as prey) were provided per individual for a period of 30 min in dark conditions, feeding rates could be easily quantified. As an endpoint, postexposure feeding inhibition in E. marinus was more sensitive to cadmium contamination than mortality. Assay calibration under field conditions demonstrated the relevance of sediment particle size in explaining individual feeding rates in uncontaminated water bodies. An evaluation of the 48-h in situ bioassay based on postexposure feeding rates indicated that it is able to discriminate between unpolluted and polluted estuarine sites. Using the harmonized protocol described here, the in situ postexposure feeding assay with E. marinus was found to be a potentially useful, cost-effective tool for assessing estuarine sediment and water quality. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. SedCT: MATLAB™ tools for standardized and quantitative processing of sediment core computed tomography (CT) data collected using a medical CT scanner

    Science.gov (United States)

    Reilly, B. T.; Stoner, J. S.; Wiest, J.

    2017-08-01

    Computed tomography (CT) of sediment cores allows for high-resolution images, three-dimensional volumes, and down core profiles. These quantitative data are generated through the attenuation of X-rays, which are sensitive to sediment density and atomic number, and are stored in pixels as relative gray scale values or Hounsfield units (HU). We present a suite of MATLAB™ tools specifically designed for routine sediment core analysis as a means to standardize and better quantify the products of CT data collected on medical CT scanners. SedCT uses a graphical interface to process Digital Imaging and Communications in Medicine (DICOM) files, stitch overlapping scanned intervals, and create down core HU profiles in a manner robust to normal coring imperfections. Utilizing a random sampling technique, SedCT reduces data size and allows for quick processing on typical laptop computers. SedCTimage uses a graphical interface to create quality tiff files of CT slices that are scaled to a user-defined HU range, preserving the quantitative nature of CT images and easily allowing for comparison between sediment cores with different HU means and variance. These tools are presented along with examples from lacustrine and marine sediment cores to highlight the robustness and quantitative nature of this method.

  15. Deformation of textural characteristics and sedimentology along micro-tidal estuarine beaches

    Digital Repository Service at National Institute of Oceanography (India)

    Dora, G.U.; SanilKumar, V.; Philip, C.S.; Johnson, G.

    Indian Journal of Geo Marine Sciences Vol. 45 (11), November 2016, pp. 1432-1444 *Corresponding author Deformation of textural characteristics and sedimentology along micro- tidal estuarine beaches G. Udhaba Dora, V. Sanil Kumar*, C... sediment is a foremost parameter for a coastal researcher/engineer/designer due to its various applications for sorting out a coastal environment. Sedimentary process at foreshore zone is a highly dynamical whereas textural characteristics...

  16. Methane and Trichloroethylene Oxidation by an Estuarine Methanotroph, Methylobacter sp. Strain BB5.1

    OpenAIRE

    Smith, Kelly S.; Costello, Andria M.; Lidstrom, Mary E.

    1998-01-01

    An estuarine methanotroph was isolated from sediment enrichments and designated Methylobacter sp. strain BB5.1. In cells grown on medium with added copper, oxidation of methane and trichloroethylene occurred with similar Ks values, but the Vmax for trichloroethylene oxidation was only 0.1% of the methane oxidation Vmax. Cells grown on low-copper medium did not oxidize trichloroethylene and showed a variable rate of methane oxidation.

  17. Shifts in the metabolic function of a benthic estuarine microbial community following a single pulse exposure to silver nanoparticles

    International Nuclear Information System (INIS)

    Echavarri-Bravo, Virginia; Paterson, Lynn; Aspray, Thomas J.; Porter, Joanne S.; Winson, Michael K.; Thornton, Barry; Hartl, Mark G.J.

    2015-01-01

    The increasing use of silver nanoparticles (AgNPs) as a biocidal agent and their potential accumulation in sediments may threaten non-target natural environmental bacterial communities. In this study a microcosm approach was established to investigate the effects of well characterized OECD AgNPs (NM-300) on the function of the bacterial community inhabiting marine estuarine sediments (salinity 31‰). The results showed that a single pulse of NM-300 AgNPs (1 mg L −1 ) that led to sediment concentrations below 6 mg Ag kg −1 dry weight inhibited the bacterial utilization of environmentally relevant carbon substrates. As a result, the functional diversity changed, but recovered after 120 h under the experimental conditions. This microcosm study suggests that AgNPs under environmentally relevant experimental conditions can negatively affect bacterial function and provides an insight into the understanding of the bacterial community response and resilience to AgNPs exposure, important for informing relevant regulatory measures. - Highlights: • AgNPs affected the bacterial community function in estuarine marine sediments. • AgNPs inhibited the bacterial utilization of environmentally relevant substrates. • Heterotrophic bacterial groups showed resilience to AgNPs after 120 h exposure. • AgNPs did not affect the bacterial community structure in sediments. - AgNPs inhibited the bacterial utilization of environmentally relevant substrates and caused temporary shifts in the bacterial functional diversity in marine estuarine sediments

  18. Strong links between metal contamination, habitat modification and estuarine larval fish distributions

    Energy Technology Data Exchange (ETDEWEB)

    McKinley, Andrew C., E-mail: andrew.mckinley@hotmail.com [Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales 2052 (Australia); Miskiewicz, Anthony [Environment and Recreation, Wollongong City Council, 41 Burelli Street, Wollongong, New South Wales 2500 (Australia); Taylor, Matthew D.; Johnston, Emma L. [Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales 2052 (Australia)

    2011-06-15

    Changes to larval fish assemblages may have far reaching ecological impacts. Correlations between habitat modification, contamination and marine larval fish communities have rarely been assessed in situ. We investigated links between the large-scale distribution of stressors and larval fish assemblages in estuarine environments. Larval fish communities were sampled using a benthic sled within the inner and outer zones of three heavily modified and three relatively unmodified estuaries. Larval abundances were significantly greater in modified estuaries, and there were trends towards greater diversity in these systems. Differences in larval community composition were strongly related to sediment metal levels and reduced seagrass cover. The differences observed were driven by two abundant species, Paedogobius kimurai and Ambassis jacksoniensis, which occurred in large numbers almost exclusively in highly contaminated and pristine locations respectively. These findings suggest that contamination and habitat alteration manifest in substantial differences in the composition of estuarine larval fish assemblages. - Highlights: > We examine contamination/habitat modification impacts on larval fish. > Larvae communities differ between modified/unmodified estuaries. > Larvae are more abundant/diverse in modified areas. > Trends are strongly related to sediment metals/seagrass cover. > Larval impacts have wider ecological importance. - We describe strong links between sediment metals contamination, habitat modification and substantial differences in the composition of the estuarine larval fish assemblage.

  19. Strong links between metal contamination, habitat modification and estuarine larval fish distributions

    International Nuclear Information System (INIS)

    McKinley, Andrew C.; Miskiewicz, Anthony; Taylor, Matthew D.; Johnston, Emma L.

    2011-01-01

    Changes to larval fish assemblages may have far reaching ecological impacts. Correlations between habitat modification, contamination and marine larval fish communities have rarely been assessed in situ. We investigated links between the large-scale distribution of stressors and larval fish assemblages in estuarine environments. Larval fish communities were sampled using a benthic sled within the inner and outer zones of three heavily modified and three relatively unmodified estuaries. Larval abundances were significantly greater in modified estuaries, and there were trends towards greater diversity in these systems. Differences in larval community composition were strongly related to sediment metal levels and reduced seagrass cover. The differences observed were driven by two abundant species, Paedogobius kimurai and Ambassis jacksoniensis, which occurred in large numbers almost exclusively in highly contaminated and pristine locations respectively. These findings suggest that contamination and habitat alteration manifest in substantial differences in the composition of estuarine larval fish assemblages. - Highlights: → We examine contamination/habitat modification impacts on larval fish. → Larvae communities differ between modified/unmodified estuaries. → Larvae are more abundant/diverse in modified areas. → Trends are strongly related to sediment metals/seagrass cover. → Larval impacts have wider ecological importance. - We describe strong links between sediment metals contamination, habitat modification and substantial differences in the composition of the estuarine larval fish assemblage.

  20. Residual fluxes of water, salt and suspended sediment in the Beypore Estuary

    Digital Repository Service at National Institute of Oceanography (India)

    AnilKumar, N.; Revichandran, C.; Sankaranarayanan, V.N.; Josanto, V.

    The monthly trends of the residual fluxes of salt and water and the transportation of suspended sediments in the Beypore estuarine system, Kerala, India were examined. At the river mouth the water flux was directed seaward during the postmonsoon...

  1. Biogenic silica in tidal freshwater marsh sediments and vegetation (Schelde estuary, Belgium)

    NARCIS (Netherlands)

    Struyf, E.; van Damme, S.; Gribsholt, B.; Middelburg, J.J.; Meire, P.

    2005-01-01

    To date, estuarine ecosystem research has mostly neglected silica cycling in freshwater intertidal marshes. However, tidal marshes can store large amounts of biogenic silica (BSi) in vegetation and sediment. BSi content of the typical freshwater marsh plants Phragmites australis, Impatiens

  2. Short-term observation of beach dynamics using cross-shore profiles and foreshore sediment

    Digital Repository Service at National Institute of Oceanography (India)

    Dora, G.U.; SanilKumar, V.; Johnson, G.; Philip, C.S.; Vinayaraj, P.

    Cross-shore beach profiles and textural characteristics of foreshore sediment were analyzed for understanding an annual cycle of intertidal beach dynamics at Devbag, an Island sheltered estuarine coast. Cross-shore transects were monitored in a...

  3. Clay mineralogy of innershelf sediments off Cochin, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Reddy, N.P.C.; Rao, N.V.N.D.; Dora, Y.L.

    Kaolinite, montmorillonite and illite are the clay minerals occurring in decreasing order of abundance in the Holocene sediments of inner shelf and adjacent coastal environments of Cochin Region. Southern part of Vembanad Lake, estuarine part...

  4. Meta-analysis of estuarine nurseries

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Densities of juvenile fishery species and other animals (all generally 100 mm total length) were summarized for shallow estuarine areas along coastal Texas and...

  5. Microbial degradation of pharmaceuticals in estuarine and coastal seawater

    Energy Technology Data Exchange (ETDEWEB)

    Benotti, Mark J. [Marine Sciences Research Center, Stony Brook University, Stony Brook, NY 11794-5000 (United States); Brownawell, Bruce J. [Marine Sciences Research Center, Stony Brook University, Stony Brook, NY 11794-5000 (United States)], E-mail: bruce.brownawell@sunysb.edu

    2009-03-15

    Microbial degradation rates were measured for 19 pharmaceuticals in estuarine and coastal surface water samples. Antipyrine, carbamazepine, cotinine, sulfamethoxazole, and trimethoprim were the most refractory (half-lives, t{sub 1/2} = 35 to >100 days), making them excellent candidates for wastewater tracers. Nicotine, acetaminophen, and fluoxetine were labile across all treatments (t{sub 1/2} = 0.68-11 days). Caffeine, diltiazem, and nifedipine were also and relatively labile in all but one of the treatments (t{sub 1/2} = 3.5-13 days). Microbial degradation of caffeine was further confirmed by production {sup 14}CO{sub 2}. The fastest decay of non-refractory compounds was always observed in more sewage-affected Jamaica Bay waters. Degradation rates for the majority of these pharmaceuticals are much slower than reported rates for small biomolecules, such as glucose and amino acids. Batch sorption experiments indicate that removal of these soluble pharmaceuticals from the water column to sediments is a relatively insignificant removal process in these receiving waters. - Microbial degradation rates were measured for 19 structurally variable pharmaceuticals in wastewater-impacted estuarine and coastal seawater.

  6. Microbial degradation of pharmaceuticals in estuarine and coastal seawater

    International Nuclear Information System (INIS)

    Benotti, Mark J.; Brownawell, Bruce J.

    2009-01-01

    Microbial degradation rates were measured for 19 pharmaceuticals in estuarine and coastal surface water samples. Antipyrine, carbamazepine, cotinine, sulfamethoxazole, and trimethoprim were the most refractory (half-lives, t 1/2 = 35 to >100 days), making them excellent candidates for wastewater tracers. Nicotine, acetaminophen, and fluoxetine were labile across all treatments (t 1/2 = 0.68-11 days). Caffeine, diltiazem, and nifedipine were also and relatively labile in all but one of the treatments (t 1/2 = 3.5-13 days). Microbial degradation of caffeine was further confirmed by production 14 CO 2 . The fastest decay of non-refractory compounds was always observed in more sewage-affected Jamaica Bay waters. Degradation rates for the majority of these pharmaceuticals are much slower than reported rates for small biomolecules, such as glucose and amino acids. Batch sorption experiments indicate that removal of these soluble pharmaceuticals from the water column to sediments is a relatively insignificant removal process in these receiving waters. - Microbial degradation rates were measured for 19 structurally variable pharmaceuticals in wastewater-impacted estuarine and coastal seawater

  7. Coastal and Estuarine Mangrove Squeeze in the Mekong and Saigon Delta

    Science.gov (United States)

    Stive, M.

    2016-02-01

    Both in the Mekong and Saigon deltas coastal squeeze is a frequent and pregnant problem, which leads to amazingly alarmous coastal and estuarine erosion rates. From the landside the squeeze is due to encroaching dike relocations and agri- and aquacultures, from the sea side it is due to decreasing sediment sources and relative sea level rise. These multiple pressures at some locations, certainly away from the sediment sources (like Ca Mau) leads to unprecedentent erosion rates. Managed retreat may be a longer term solution, but this will require a new way of thinking. Sandy and silt nourishment strategies may be an innovative alternative, but will require underbuilding scientific and practical research.

  8. Distribution of the Luminous Bacterium Beneckea harveyi in a Semitropical Estuarine Environment

    Science.gov (United States)

    O'Brien, Catherine H.; Sizemore, Ronald K.

    1979-01-01

    Bioluminescent bacteria were found in the water column, sediment, shrimp, and gastrointestinal tract of marine fishes from the semitropical estuarine environment of the East Lagoon, Galveston Island, Tex. Populations in the water column decreased during cold weather while sedimentary populations persisted. The highest percentages of luminous organisms were isolated from the gastrointestinal tract of marine fishes, where they persisted during 5 days of starvation. The presence of chitin temporarily increased intestinal populations. All isolates were Beneckea harveyi, whose natural habitat appears to be the gut of fishes and whose free-living reservoir appears to be marine sediments. PMID:16345465

  9. Land scale biogeography of arsenic biotransformation genes in estuarine wetland.

    Science.gov (United States)

    Zhang, Si-Yu; Su, Jian-Qiang; Sun, Guo-Xin; Yang, Yunfeng; Zhao, Yi; Ding, Junjun; Chen, Yong-Shan; Shen, Yu; Zhu, Guibing; Rensing, Christopher; Zhu, Yong-Guan

    2017-06-01

    As an analogue of phosphorus, arsenic (As) has a biogeochemical cycle coupled closely with other key elements on the Earth, such as iron, sulfate and phosphate. It has been documented that microbial genes associated with As biotransformation are widely present in As-rich environments. Nonetheless, their presence in natural environment with low As levels remains unclear. To address this issue, we investigated the abundance levels and diversities of aioA, arrA, arsC and arsM genes in estuarine sediments at low As levels across Southeastern China to uncover biogeographic patterns at a large spatial scale. Unexpectedly, genes involved in As biotransformation were characterized by high abundance and diversity. The functional microbial communities showed a significant decrease in similarity along the geographic distance, with higher turnover rates than taxonomic microbial communities based on the similarities of 16S rRNA genes. Further investigation with niche-based models showed that deterministic processes played primary roles in shaping both functional and taxonomic microbial communities. Temperature, pH, total nitrogen concentration, carbon/nitrogen ratio and ferric iron concentration rather than As content in these sediments were significantly linked to functional microbial communities, while sediment temperature and pH were linked to taxonomic microbial communities. We proposed several possible mechanisms to explain these results. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

  10. Restoration of estuarine tidal mudflat sediments after hypoxia

    DEFF Research Database (Denmark)

    Van Colen, Carl; Montserrat, F; Middelburg, JJ

    by facilitative and inhibitive interactions: early colonizers had a positive effect on subsequent colonizers, while later succession species negatively affected the stable conditions created by the early colonizing tube-builders. Transitions between different stages were related to changes in environmental...

  11. Distribution and persistence of the anti sea-lice drug teflubenzuron in wild fauna and sediments around a salmon farm, following a standard treatment

    International Nuclear Information System (INIS)

    Samuelsen, Ole B.; Lunestad, Bjørn T.; Hannisdal, Rita; Bannister, Raymond; Olsen, Siri; Tjensvoll, Tore; Farestveit, Eva; Ervik, Arne

    2015-01-01

    The salmon louse (Lepeoptheirus salmonis) is a challenge in the farming of Atlantic salmon (Salmo salar). To treat an infestation, different insecticides are used like the orally administered chitin synthetase inhibitor teflubenzuron. The concentrations and distribution of teflubenzuron were measured in water, organic particles, marine sediment and biota caught in the vicinity of a fish farm following a standard medication. Low concentrations were found in water samples whereas the organic waste from the farm, collected by sediment traps had concentrations higher than the medicated feed. Most of the organic waste was distributed to the bottom close to the farm but organic particles containing teflubenzuron were collected 1100 m from the farm. The sediment under the farm consisted of 5 to 10% organic material and therefore the concentration of teflubenzuron was much lower than in the organic waste. Teflubenzuron was persistent in the sediment with a stipulated halflife of 170 days. Sediment consuming polychaetes had high but decreasing concentrations of teflubenzuron throughout the experimental period, reflecting the decrease of teflubenzuron in the sediment. During medication most wild fauna contained teflubenzuron residues and where polychaetes and saith had highest concentrations. Eight months later only polychaetes and some crustaceans contained drug residues. What dosages that induce mortality in various crustaceans following short or long-term exposure is not known but the results indicate that the concentrations in defined individuals of king crab, shrimp, squat lobster and Norway lobster were high enough shortly after medication to induce mortality if moulting was imminent. Considering food safety, saith and the brown meat of crustaceans contained at first sampling concentrations of teflubenzuron higher than the MRL-value set for Atlantic salmon. The concentrations were, however, moderate and the amount of saith fillet or brown meat of crustaceans to be

  12. Distribution and persistence of the anti sea-lice drug teflubenzuron in wild fauna and sediments around a salmon farm, following a standard treatment

    Energy Technology Data Exchange (ETDEWEB)

    Samuelsen, Ole B. [Institute of Marine Research, P.O. Box 1870 Nordnes, N-5817 Bergen (Norway); Lunestad, Bjørn T.; Hannisdal, Rita [National Institute of Nutrition and Seafood Research, P.O. Box 2029 Nordnes, N-5817 Bergen (Norway); Bannister, Raymond; Olsen, Siri [Institute of Marine Research, P.O. Box 1870 Nordnes, N-5817 Bergen (Norway); Tjensvoll, Tore [National Institute of Nutrition and Seafood Research, P.O. Box 2029 Nordnes, N-5817 Bergen (Norway); Farestveit, Eva; Ervik, Arne [Institute of Marine Research, P.O. Box 1870 Nordnes, N-5817 Bergen (Norway)

    2015-03-01

    The salmon louse (Lepeoptheirus salmonis) is a challenge in the farming of Atlantic salmon (Salmo salar). To treat an infestation, different insecticides are used like the orally administered chitin synthetase inhibitor teflubenzuron. The concentrations and distribution of teflubenzuron were measured in water, organic particles, marine sediment and biota caught in the vicinity of a fish farm following a standard medication. Low concentrations were found in water samples whereas the organic waste from the farm, collected by sediment traps had concentrations higher than the medicated feed. Most of the organic waste was distributed to the bottom close to the farm but organic particles containing teflubenzuron were collected 1100 m from the farm. The sediment under the farm consisted of 5 to 10% organic material and therefore the concentration of teflubenzuron was much lower than in the organic waste. Teflubenzuron was persistent in the sediment with a stipulated halflife of 170 days. Sediment consuming polychaetes had high but decreasing concentrations of teflubenzuron throughout the experimental period, reflecting the decrease of teflubenzuron in the sediment. During medication most wild fauna contained teflubenzuron residues and where polychaetes and saith had highest concentrations. Eight months later only polychaetes and some crustaceans contained drug residues. What dosages that induce mortality in various crustaceans following short or long-term exposure is not known but the results indicate that the concentrations in defined individuals of king crab, shrimp, squat lobster and Norway lobster were high enough shortly after medication to induce mortality if moulting was imminent. Considering food safety, saith and the brown meat of crustaceans contained at first sampling concentrations of teflubenzuron higher than the MRL-value set for Atlantic salmon. The concentrations were, however, moderate and the amount of saith fillet or brown meat of crustaceans to be

  13. Mathematical simulation of sediment and radionuclide transport in estuaries

    International Nuclear Information System (INIS)

    Onishi, Y.; Trent, D.S.

    1982-11-01

    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

  14. Tidal variations in the Sundarbans estuarine system, India

    Digital Repository Service at National Institute of Oceanography (India)

    Chatterjee, M.; Shankar, D.; Sen, G.K.; Sanyal, P.; Sundar, D.; Michael, G.S.; Chatterjee, A.; Amol, P.; Mukherjee, D.; Suprit, K.; Mukherjee, A.; Vijith, V.; Chatterjee, S.; Basu, A.; Das, M.; Chakraborti, S.; Kalla, A.; Misra, S.K.; Mukhopadhyay, S.; Mandal, G.; Sarkar, K.

    Situated in the eastern coastal state of West Bengal, the Sundarbans Estuarine System (SES) is India’s largest monsoonal, macro-tidal delta-front estuarine system. It comprises the southernmost part of the Indian portion of the Ganga...

  15. 77 FR 60107 - National Estuarine Research Reserve System

    Science.gov (United States)

    2012-10-02

    ... awareness and community involvement in stewardship, incompatible use by visitors, and ecological impacts of... DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Estuarine Research Reserve System AGENCY: Estuarine Reserves Division, Office of Ocean and Coastal Resource Management...

  16. Rising tides, cumulative impacts and cascading changes to estuarine ecosystem functions.

    Science.gov (United States)

    O'Meara, Theresa A; Hillman, Jenny R; Thrush, Simon F

    2017-08-31

    In coastal ecosystems, climate change affects multiple environmental factors, yet most predictive models are based on simple cause-and-effect relationships. Multiple stressor scenarios are difficult to predict because they can create a ripple effect through networked ecosystem functions. Estuarine ecosystem function relies on an interconnected network of physical and biological processes. Estuarine habitats play critical roles in service provision and represent global hotspots for organic matter processing, nutrient cycling and primary production. Within these systems, we predicted functional changes in the impacts of land-based stressors, mediated by changing light climate and sediment permeability. Our in-situ field experiment manipulated sea level, nutrient supply, and mud content. We used these stressors to determine how interacting environmental stressors influence ecosystem function and compared results with data collected along elevation gradients to substitute space for time. We show non-linear, multi-stressor effects deconstruct networks governing ecosystem function. Sea level rise altered nutrient processing and impacted broader estuarine services ameliorating nutrient and sediment pollution. Our experiment demonstrates how the relationships between nutrient processing and biological/physical controls degrade with environmental stress. Our results emphasise the importance of moving beyond simple physically-forced relationships to assess consequences of climate change in the context of ecosystem interactions and multiple stressors.

  17. Spatial distribution of trace elements in the surface sediments of a major European estuary (Loire Estuary, France): Source identification and evaluation of anthropogenic contribution

    Science.gov (United States)

    Coynel, Alexandra; Gorse, Laureline; Curti, Cécile; Schafer, Jörg; Grosbois, Cécile; Morelli, Guia; Ducassou, Emmanuelle; Blanc, Gérard; Maillet, Grégoire M.; Mojtahid, Meryem

    2016-12-01

    Assessing the extent of metal contamination in estuarine surface sediments is hampered by the high heterogeneity of sediment characteristics, the spatial variability of trace element sources, sedimentary dynamics and geochemical processes in addition to the need of accurate reference values for deciphering natural to anthropogenic contribution. Based on 285 surface sediment samples from the Loire Estuary, the first high-resolution spatial distributions are presented for grain-size, particulate organic carbon (POC) and the eight metals/metalloids identified as priority contaminants (Cd, Zn, Pb, Cu, As, Cr, Ni, Hg) plus Ag (an urban tracer). Grain-size and/or POC are major factors controlling the spatial distribution of trace element concentrations. The V-normalized trace metal concentrations divided by the V-normalized concentrations in the basin geochemical background showed the highest Enrichment Factors for Ag and Hg (EF; up to 34 and 140, respectively). These results suggest a severe contamination in the Loire Estuary for both elements. Intra-estuarine Ag and Hg anomalies were identified by comparison between respective normalized concentrations in the Loire Estuary surface sediments and those measured in the surface sediments at the outlet of the Loire River System (watershed-derived). Anthropogenic intra-estuarine Ag and Hg stocks in the uppermost centimetre of the sediment compared with rough annual fluvial flux estimates suggest that the overall strong Enrichment Factors for Ag (EFAg) and and Hg (EFHg) in the Loire Estuary sediments are mainly due to watershed-derived inputs, highlighting the need of high temporal hydro-geochemical monitoring to establish reliable incoming fluxes. Significant correlations obtained between EFCd and EFAg, EFCu and POC and EFHg and POC revealed common behavior and/or sources. Comparison of trace element concentrations with ecotoxicological indices (Sediment Quality Guidelines) provides first standardized information on the

  18. Development of a Standardized Approach for Assessing Potential Risks to Amphibians Exposed to Sediment and Hydric Soils

    Science.gov (United States)

    2004-05-01

    different foods in amphibian tests. Possible foods considered for this study included boiled spinach, boiled lettuce , fish flakes, TetraMin...other foods such as boiled spinach or lettuce . • Sediment tests in flow-through chambers are preferable over static-renewal systems because of... hybridization may be possible. Amphibian Ecological Risk Assessment Guidance Manual Q:\\mw97\\Projects\\9070045\\419\\Appendix C\\appC-1

  19. Using recent hurricanes and associated event layers to evaluate regional storm impacts on estuarine-wetland systems

    Science.gov (United States)

    Smith, C. G.; Marot, M. E.; Osterman, L. E.; Adams, C. S.; Haller, C.; Jones, M.

    2016-12-01

    Tropical cyclones are a major driver of change in coastal and estuarine environments. Heightened waves and sea level associated with tropical cyclones act to erode sediment from one environment and redistribute it to adjacent environments. The fate and transport of this redistributed material is of great importance to the long-term sediment budget, which in turns affects the vulnerability of these coastal systems. The spatial variance in both storm impacts and sediment redistribution is large. At the regional-scale, difference in storm impacts can often be attributed to natural variability in geologic parameters (sediment availability/erodibility), coastal geomorphology (including fetch, shoreline tortuosity, back-barrier versus estuarine shoreline, etc.), storm characteristics (intensity, duration, track/approach), and ecology (vegetation type, gradient, density). To assess storm characteristics and coastal geomorphology on a regional-scale, cores were collected from seven Juncus marshes located in coastal regions of Alabama and Mississippi (i.e., Mobile Bay, Bon Secour Bay, Mississippi Sound, and Grand Bay) expected to have been impacted by Hurricane Frederic (1979). All cores were sectioned and processed for water content, organic matter (loss-on-ignition), and select cores analyzed for foraminiferal assemblages, stable isotopes and bulk metals to aid in the identification of storm events. Excess lead-210 and cesium-137 were used to develop chronologies for the cores and evaluate mass accumulation rates and sedimentation rates. Temporal variations in accumulation rates of inorganic and organic sediments were compared with shoreline and areal change rates derived from historic aerial imagery to evaluate potential changes in sediment exchange prior to, during, and following the storm. A combined geospatial and geologic approach will improve our understanding of coastal change in estuarine marsh environments, as well help refine the influence of storms on regional

  20. EXTRACTION OF SEDIMENT-BOUND CHLORINATED ORGANIC COMPOUNDS: IMPLICATIONS ON FATE AND HAZARD ASSESSMENT. (R825513C007)

    Science.gov (United States)

    Five methods were used for the extraction of hexachlorobutadiene and chlorobenzenes from a contaminated estuarine sediment. The following extraction methods were used: Soxhlet extraction, sonication and solvent extraction, sequential solvent extraction, saponification and solv...

  1. Clay mineral distribution in the shelf sediments off the northern part of the east coast of india

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, V.P.; Reddy, N.P.C.; Rao, Ch.M.

    Forty-eight sediment samples from the continental shelf between Visakhapatnam and the Ganges were analysed by X-ray diffraction for the composition and distribution of clay minerals. Estuarine samples of the Hooghly are dominated by illite...

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

    Directory of Open Access Journals (Sweden)

    D. R. Corbett

    2010-10-01

    Full Text Available For at least the past several decades, North Carolina's Neuse River Estuary (NRE has been subject to water quality problems relating to increased eutrophication. Research initiated in the past several years have addressed the nutrient processes of the water column and the passive diffusion processes of the benthic sedimentary environment. Resuspension of bottom sediments, by bioturbation, tides, or winds, may also have a significant effect on the flux of nutrients in an estuarine system These processes can result in the advective transport of sediment porewater, rich with nitrogen, phosphorus and carbon, into the water column. Thus, estimates of nutrient and carbon inputs from the sediments may be too low.

    This study focused on the potential change in bottom water nutrient concentrations associated with measured resuspension events. Previous research used short-lived radionuclides and meteorological data to characterize the sediment dynamics of the benthic system of the estuary. These techniques in conjunction with the presented porewater inventories allowed evaluation of the depth to which sediments have been disturbed and the advective flux of nutrients to the water column. The largest removal episode occurred in the lower NRE as the result of a wind event and was estimated that the top 2.2 cm of sediment and corresponding porewater were removed. NH4+ advective flux (resuspended was 2 to 6 times greater than simply diffusion. Phosphate fluxes were estimated to be 15 times greater than the benthic diffusive flux. Bottom water conditions with elevated NH4+ and PO43− indicate that nutrients stored in the sediments continue to play an important role in overall water quality and this study suggests that the advective flux of nutrients to the water column is critical to understand estuarine nutrient cycling.

  3. Ecology of Vibrio vulnificus in estuarine waters of eastern North Carolina.

    Science.gov (United States)

    Pfeffer, Courtney S; Hite, M Frances; Oliver, James D

    2003-06-01

    While several studies on the ecology of Vibrio vulnificus in Gulf Coast environments have been reported, there is little information on the distribution of this pathogen in East Coast waters. Thus, we conducted a multiyear study on the ecology of V. vulnificus in estuarine waters of the eastern United States, employing extensive multiple regression analyses to reveal the major environmental factors controlling the presence of this pathogen, and of Vibrio spp., in these environments. Monthly field samplings were conducted between July 2000 and April 2002 at six different estuarine sites along the eastern coast of North Carolina. At each site, water samples were taken and nine physicochemical parameters were measured. V. vulnificus isolates, along with estuarine bacteria, Vibrio spp., Escherichia coli organisms, and total coliforms, were enumerated in samples from each site by using selective media. During the last 6 months of the study, sediment samples were also analyzed for the presence of vibrios, including V. vulnificus. Isolates were confirmed as V. vulnificus by using hemolysin gene PCR or colony hybridization. V. vulnificus was isolated only when water temperatures were between 15 and 27 degrees C, and its presence correlated with water temperature and dissolved oxygen and vibrio levels. Levels of V. vulnificus in sediments were low, and no evidence for an overwintering in this environment was found. Multiple regression analysis indicated that vibrio levels were controlled primarily by temperature, turbidity, and levels of dissolved oxygen, estuarine bacteria, and coliforms. Water temperature accounted for most of the variability in the concentrations of both V. vulnificus (47%) and Vibrio spp. (48%).

  4. Dissolved Vanillin as Tracer for Estuarine Lignin Conversion

    Science.gov (United States)

    Edelkraut, F.

    1996-12-01

    Lignin is produced only by vascular plants and therefore can be used as a tracer for terrestrial organic carbon input to the estuarine and marine environments. Lignin measurements have been done by analyses of the oxidation products such as vanillin or 4-hydroxybenzaldehyde. In the Elbe Estuary, free dissolved vanillin was analysed in order to test whether such measurements yield information on terrestrial carbon inputs into the Estuary and on the vanillin derived from lignin oxidation. In the period 1990-1992, concentrations of dissolved vanillin in the Elbe ranged from 0 to 60 μ g l -1(mean: 8 μg l -1). Higher values were found in areas of increased microbial activity such as the turbidity zone and the river mouth where the water chemistry is influenced by large tidal flats. No correlation was found between dissolved vanillin and suspended matter concentrations, although lignin is normally associated with suspended particulate matter, nor was a covariance seen between dissolved vanillin and the terrestrial carbon inputs into the Estuary. Apparently, biological conversion of lignin was faster than the transport processes, and local sources were more dominant for the vanillin concentration than riverine sources. The dissolved vanillin turnover was fast and, consequently, a significant amount of lignin may be converted within an estuary. In sediments from the Estuary, the concentrations of dissolved vanillin were similar to those found in the water phase and showed no clear vertical profile. The sediment is unlikely to be the source for vanillin.

  5. Standardization of radiochemical techniques aiming the study of Hg volatilization and methylation in water and sediment of gold mining areas in the Amazon region

    International Nuclear Information System (INIS)

    Guimaraes, Jean Remy Davee

    1992-09-01

    Methylation of inorganic Hg in aquatic systems is a key process in the environmental cycling of this metal, not yet studied in tropical conditions. Radiochemical techniques were adapted and simplified, aiming at the study of Hg volatilization and methylation in water and sediment of gold mining areas in the Amazon region. Preliminary experiments showed, in 35 days volatilization of up to 32 % of 203 Hg 2+ added to aqueous solutions. Acid K 2 Cr 2 0 7 0.1 M solutions were not effective in 203 Hg 0 trapping and the latter was highly and irreversibly absorbed by a variety of synthetic materials commonly used in laboratory work. Considerably simplified versions of the Furutani and Rudd (1980) radiochemical technique for the determination of methylation rates in environmental samples were developed and showed efficiencies close to 90 % in tests with methyl- 2 0 3 H g standards. In-situ incubations of surface sediments were performed in the Madeira River gold mining region, Rondonia State, Brazil, and potential net Hg methylation rates (MR) of up to 1 %.g-1.h-1 were found in black-water affluent like the Mutum-Parana and Jamari rivers and in the Samuel reservoir. MRs in the Madeira River sediments were lower, ranging 10-5 to 10-3 %.g-1.h-1 . MRs obtained in incubations of samples some weeks after collection were one or two orders of magnitude lower than those resulting from in-situ incubations. Methylation in autoclaved samples was close to minimum detectable rates. MRs in surface water samples was in all cases < 7.10-7 %.ml-1.h-1. The determination of the predominant methylation sites will allow a better standardization of the technique described herein, suitable for MR determinations even under the unfavorable conditions prevailing in the Amazon region. (author)

  6. Hydrologic influence on redox dynamics in estuarine environments

    Science.gov (United States)

    Michael, H. A.; Kim, K. H.; Guimond, J. A.; Heiss, J.; Ullman, W. J.; Seyfferth, A.

    2017-12-01

    Redox conditions in coastal aquifers control reactions that impact nutrient cycling, contaminant release, and carbon budgets, with implications for water resources and ecosystem health. Hydrologic changes can shift redox boundaries and inputs of reactants, especially in dynamic coastal systems subject to fluctuations on tidal, lunar, and longer timescales. We present two examples of redox shifts in estuarine systems in Delaware, USA: a beach aquifer and a saltmarsh. Beach aquifers are biogeochemical hot spots due to mixing between fresh groundwater and infiltrating seawater. At Cape Henlopen, DE, geochemical measurements identified reactions in the intertidal aquifer that include cycling of carbon, nitrogen, iron, and sulfur. Measurements and modeling illustrate that redox potential as well as the locations of redox reactions shift on tidal to seasonal timescales and in response to changing beach and aquifer properties, impacting overall rates of reactions such as denitrification that reduces N loads to coastal waters. In the St. Jones National Estuarine Research Reserve, tidal fluctuations in channels cause periodic groundwater-surface water exchange, water table movement, and intermittent flooding that varies spatially across the saltmarsh. These changes create shifts in redox potential that are greatest near channels and in the top 20 cm of sediments. The magnitude of redox change depends on hydrologic setting (near channels or in marsh interior), hydrologic conditions (tidal stage, seasonal shifts), as well as prevalence of macropores created by crab burrows that change seasonally with crab activity. These shifts correspond to changes in porewater chemistry that have implications for nutrient cycling and carbon export to the ocean. Understanding hydrologic influence on redox geochemistry is critical for predicting how these systems and their ecosystem services may change in the future in response to anthropogenic and climate change.

  7. Modelling Watershed and Estuarine Controls on Salt Marsh Distributions

    Science.gov (United States)

    Yousefi Lalimi, F.; Marani, M.; Murray, A. B.; D'Alpaos, A.

    2017-12-01

    The formation and evolution of tidal platforms have been extensively studied through observations and models, describing landform dynamics as a result of the local interactions and feedbacks among hydrodynamics, vegetation, and sediment transport. However, existing work mainly focuses on individual marsh platforms and, possibly, their immediate surrounding, such that the influence and controls on marsh dynamics of inland areas (through fluvial inputs) and of exchanges with the ocean have not been comprehensively and simultaneously accounted for. Here, we develop and use a process-based model to evaluate the relative role of watershed, estuarine, and ocean controls on salt marsh accretionary and depositional/erosional dynamics and define how these factors interact to determine salt marsh resilience to environmental change at the whole-estuary scale. Our results, in line with previous work, show that no stable equilibrium exists for the erosional dynamics of the marsh/tidal flat boundary. In addition, we find that under some circumstances, vertical accretion/erosion dynamics can lead to transitions between salt marsh and tidal flat equilibrium states that occur much more rapidly than marsh/tidal flat boundary erosion or accretion could. We further define, in the multidimensional space of estuarine-scale morphodynamic forcings, the basins of attractions leading to marsh-dominated and tidal-flat-dominated estuaries. The relatively slow dynamics asymptotically leading to marsh- or tidal-flat- dominance in many cases suggest that estuaries are likely to be found, at any given time, in a transition state dictated by temporal variations in environmental forcings.

  8. Estuarine Oceanography. CEGS Programs Publication Number 18.

    Science.gov (United States)

    Wright, F. F.

    Estuarine Oceanography is one in a series of single-topic problem modules intended for use in undergraduate and earth science courses. Designed for those interested in coastal oceanography or limnology, the module is structured as a laboratory supplement for undergraduate college classes but should be useful at all levels. The module has two…

  9. Conservation Priority Index for Estuarine Fish (COPIEF)

    Science.gov (United States)

    Branco, Paulo; Costa, José Lino; Raposo de Almeida, Pedro

    2008-12-01

    Public awareness regarding environmental issues has increased in recent decades. The increasing number of impact assessment studies, management and conservation plans, as well as ecological monitoring studies, demand new and more efficient techniques. Indices are an important tool to aid biologists in these studies and should allow an easier comprehension of the data by managers, decision-makers and the general public. This study presents the first multi-metrical index able to establish a hierarchical ordination of the conservation priority of the estuarine fish species using 72 species from 16 estuarine systems (W and S coasts of Portugal). The index is composed of 10 metrics, comprising species life traits, distribution and population trends. The information needed to score each metric was gathered from the published literature and the index validation was done by external means. This methodology allowed the definition of those fish species most in need of conservation planning, and those less prone to extinction in Portuguese estuarine systems. The proposed index fills a gap in our knowledge and provides a useful tool to the scientific community and to the decision-makers, being a breakthrough in the field of conservation planning of estuarine fish species.

  10. Assessing estuarine biota in southern California

    Science.gov (United States)

    Kevin D. Lafferty

    2005-01-01

    In southern California, most estuarine wetlands are gone, and what little habitat remains is degraded. For this reason, it is often of interest to assess the condition of estuaries over time, such as when determining the success of a restoration project. To identify impacts or opportunities for restoration, we also may want to know how a particular estuary, or area...

  11. Environmental risk assessment of cobalt and manganese from industrial sources in an estuarine system.

    Science.gov (United States)

    Barrio-Parra, F; Elío, J; De Miguel, E; García-González, J E; Izquierdo, M; Álvarez, R

    2018-04-01

    A total of 74 samples of soil, sediment, industrial sludge, and surface water were collected in a Mediterranean estuarine system in order to assess the potential ecological impact of elevated concentrations of Co and Mn associated with a Terephthalic (PTA) and Isophthalic (PIPA) acids production plant. Samples were analyzed for elemental composition (37 elements), pH, redox potential, organic carbon, and CaCO 3 content, and a group of 16 selected samples were additionally subjected to a Tessier sequential extraction. Co and Mn soil concentrations were significantly higher inside the industrial facility and around its perimeter than in background samples, and maximum dissolved Co and Mn concentrations were found in a creek near the plant's discharge point, reaching values 17,700 and 156 times higher than their respective background concentrations. The ecological risk was evaluated as a function of Co and Mn fractionation and bioavailability which were controlled by the environmental conditions generated by the advance of seawater into the estuarine system during high tide. Co appeared to precipitate near the river mouth due to the pH increase produced by the influence of seawater intrusion, reaching hazardous concentrations in sediments. In terms of their bioavailability and the corresponding risk assessment code, both Co and Mn present sediment concentrations that result in medium to high ecological risk whereas water concentrations of both elements reach values that more than double their corresponding Secondary Acute Values.

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

    Science.gov (United States)

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

    2016-05-01

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

  13. Linkages between the spatial toxicity of sediments and sediment dynamics in the Yangtze River Estuary and neighboring East China Sea.

    Science.gov (United States)

    Gao, Jinjuan; Shi, Huahong; Dai, Zhijun; Mei, Xuefei; Zong, Haibo; Yang, Hongwei; Hu, Lingling; Li, Shushi

    2018-02-01

    Anthropogenic activities are driving an increase in sediment contamination in coastal areas. This poses significant challenges for the management of estuarine ecosystems and their adjacent seas worldwide. However, few studies have been conducted on how dynamic mechanisms affect the sediment toxicity in the estuarine environment. This study was designed to investigate the linkages between sediment toxicity and hydrodynamics in the Yangtze River Estuary (YRE) area. High sediment toxicity was found in the Yangtze River mouth (Region I), the depocenter of the Yangtze River Delta (Region II), and the southeastern area of the adjacent sea (Region III), while low sediment toxicity was found in the northeastern offshore region (Region IV). A spatial comparison analysis and regression model indicated that the distributed pattern of sediment toxicity was likely related to hydrodynamics and circumfluence in the East China Sea (ECS) shelf. Specifically, high sediment toxicity in Region I may be affected by the Yangtze River Pump (YRP) and the low hydrodynamics there, and high toxicity in Region II can be influenced by the low sediment dynamics and fine sediment in the depocenter. The high sediment toxicity in Region III might be related to the combination of the YRP and Taiwan Warm Current, while the low toxicity in Region IV may be influenced by the local coarse-grained relict sand with strong sediment dynamics there. The present research results further suggest that it is necessary to link hydrodynamics and the spatial behavior of sediment and sediment-derived pollutants when assessing the pollution status of estuarine environments, especially for those mega-estuaries and their neighboring ocean environments with complex waves, tides and ocean currents. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Reductive dehalogenation of polychlorinated biphenyls by anaerobic microorganisms enriched from Dutch sediments

    NARCIS (Netherlands)

    HartkampCommandeur, LCM; Gerritse, J; Govers, HAJ; Parsons, [No Value

    The dehalogenation of PCBs by anaerobic microbial cultures enriched from Dutch sediments was investigated. One mixed culture originating from estuarine sediments of the River Rhine (the Chemie Harbour), dehalogenated 2,2',3,3',4,4'- and 2,2,',3,3',6,6'-hexachlorobiphenyls (HCB) to yield penta- and

  15. The effect of sediment transport on eelgrass development – and vice versa

    NARCIS (Netherlands)

    Dijkstra, J.T.

    2007-01-01

    By changing flow patterns and sediment transport, aquatic vegetation can affect the development of estuarine bed topography. Besides, since the sediment transport also determines the amount of light available for photosynthetic growth, the presence of vegetation can also affect its own development.

  16. Estuarine geochemistry of 224Ra, 226Ra, and 222Rn

    International Nuclear Information System (INIS)

    Elsinger, R.J.

    1982-01-01

    Desorption from river borne sediments is the most likely source of the excess 226 Ra. Laboratory mixing experiments on Pee Dee River sediments show an increase in 226 Ra desorption with increasing salinities with maximum desorption occurring at or above 20 0 /oo salinity. Desorption and diffusion are the sources for 226 Ra in the estuarine systems. In Winyah Bay the 228 Ra/ 226 Ra activity ratio does not change significantly with salinity, averaging around 1.4, indicating desorption as the major source of 228 Ra. In the Yangtze River the 228 Ra/ 226 Ra activity ratio is constant (approx.1.90) until increasing linearly above 16 0 /oo. A diffusive flux from regeneration by 232 Th decay in shelf sediments is the source of the increase. In Delaware Bay 228 Ra increases faster than 226 Ra in the less than or equal to22 0 /oo water, indicating a source in addition to desorption. The increase can be balanced by a 0.33 dpm/cm 2 -year flux over the upper part of the Bay where fine grained sediments predominate. 224 Ra behavior is controlled by its 3.64 day half-life. In Winyah Bay a flux of around 0.4 dpm/cm 2 -day is necessary to support the standing crop of non-desorbed 224 Ra in the water column. In Delaware Bay the nearly constant 224 Ra in concentration over the 2.5 0 /oo to 12 0 /oo salinity range are maintained by regeneration from 228 Th in the turbidity maximum zones and diffusion from bottom sediments. Water leaving on ebb tide from a salt marsh on Delaware Bay had increases in all three radium isotopes ( 224 Ra > 228 Ra > 226 Ra) compared to water coming in on the flood tide. Excess 222 Rn concentrations in a fresh water section of the Pee Dee River show a decreasing downstream gradient. Using these gradients to determine evasion rates, stagnant film thicknesses range from 21μ to 62μ

  17. Suspended sediment and sediment-associated contaminants in San Francisco Bay

    Science.gov (United States)

    Schoellhamer, D.H.; Mumley, T.E.; Leatherbarrow, J.E.

    2007-01-01

    Water-quality managers desire information on the temporal and spatial variability of contaminant concentrations and the magnitudes of watershed and bed-sediment loads in San Francisco Bay. To help provide this information, the Regional Monitoring Program for Trace Substances in the San Francisco Estuary (RMP) takes advantage of the association of many contaminants with sediment particles by continuously measuring suspended-sediment concentration (SSC), which is an accurate, less costly, and more easily measured surrogate for several trace metals and organic contaminants. Continuous time series of SSC are collected at several sites in the Bay. Although semidiurnal and diurnal tidal fluctuations are present, most of the variability of SSC occurs at fortnightly, monthly, and semiannual tidal time scales. A seasonal cycle of sediment inflow, wind-wave resuspension, and winnowing of fine sediment also is observed. SSC and, thus, sediment-associated contaminants tend to be greater in shallower water, at the landward ends of the Bay, and in several localized estuarine turbidity maxima. Although understanding of sediment transport has improved in the first 10 years of the RMP, determining a simple mass budget of sediment or associated contaminants is confounded by uncertainties regarding sediment flux at boundaries, change in bed-sediment storage, and appropriate modeling techniques. Nevertheless, management of sediment-associated contaminants has improved greatly. Better understanding of sediment and sediment-associated contaminants in the Bay is of great interest to evaluate the value of control actions taken and the need for additional controls. ?? 2007 Elsevier Inc. All rights reserved.

  18. A Miocene wave-dominated estuarine system in the Paraíba Basin, northeastern Brazil

    Science.gov (United States)

    Gandini, Rosana; Rossetti, Dilce de Fátima; Netto, Renata Guimarães; Góes, Ana Maria

    2017-11-01

    A number of publications have documented the effect of the Miocene transgression on several coasts of the world. However, this event is incompletely documented along the Brazilian margin, despite the existence of an impressive record of Miocene deposits exposed mostly as several coastal cliffs along more than 5000 km of distance. The transgressive nature of Miocene deposits, so far recognized only in a few localities of northeastern Brazil, needs to be amplified in order to better characterize the impact of the Miocene transgression in eastern South America. In this work, we provide facies analysis of early/middle Miocene strata exposed in the Paraíba Basin, northeastern Brazil, aiming reconstruct the depositional paleoenvironments and analyze their evolution within the context of relative sea-level fluctuations data. The results revealed deposits characterized by several features that were related to the action of tidal currents, such as alternating thicker/thinner forest packages, abundant reactivation surfaces, mud drapes and oppositely-dipping (herringbone) cross sets. These sedimentary structures were associated with an ichnological assemblage indicative of marine-influenced and brackish water, best represented by Ophiomorpha, Planolites-Palaeophycus-Thalassinoides and Thallassinoides-Planolites-Palaeophycus ichnofabrics. Sedimentation occurred in environments consisting of estuarine channel, estuarine central basin, tidal inlet/tidal channel, tidal delta/washover, tidal flat/shoal and foreshore, which were related to an estuarine setting, at least in part of a wave-dominated type. Analysis of facies stratal patterns led to suggest that the estuarine deposits of the Paraíba Basin reflect a rise in relative sea level probably during the transgressive and/or highstand stage of a depositional sequence formed directly overlying Cretaceous rocks. This rise can be correlated with the worldwide early/mid Miocene marine transgression. However, while the eustatic sea

  19. Multiscale physical processes of fine sediment in an estuary

    NARCIS (Netherlands)

    Wan, Y.

    2015-01-01

    This study presented in this book investigates micro- and macro- scale physical processes of a large-scale fine sediment estuarine system with a moderate tidal range as well as a highly seasonal-varying freshwater inflow. Based on a series measured, experimented and modeled results, the research

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

    Digital Repository Service at National Institute of Oceanography (India)

    Alagarsamy, R.

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

  1. Oxidative demethylation of monomethylmercury in sediments

    International Nuclear Information System (INIS)

    Oremland, R.S.

    1991-01-01

    Previous studies suggested that demethylation of monomethylmercury proceeds in nature by a simple organo-mercury lyase reaction resulting in the production of CH 4 and Hg 2+ , which is further reduced to Hg 0 . Addition of 14 CH 3 HgI to sediments resulted in the production of mainly 14 CO 2 and some 14 CH 4 . In the case of estuarine sediments, production of both these gases was only observed under anaerobiosis, and was totally inhibited by MoO 4 2- , which indicated the involvement of sulfate-reducing bacteria. In the case of anaerobic freshwater sediments, results with inhibitors indicated that both methanogens and sulfate reducers were involved in this oxidative demethylation. Aerobic incubation of estuarine sediments resulted in the production of only 14 CH 4 , indicating the importance of the organo-mercurial lyase reaction under this condition. However, in freshwater sediments, this reaction was not observed, and the oxidative demethylation reaction was predominant either under aerobic or anaerobic conditions. A methylotrophic methanogen (GS-16) was able to form traces of 14 CH 4 and 14 CO 2 from 14 CH 3 HgI, and some strains of sulfate-reducers formed traces of 14 CH 4 . Addition of methanol to anaerobic freshwater sediments partially inhibited production of 14 CH 4 and 14 CO 2 , but not CH 4 . These results suggest that oxidative demethylation proceeds by an established pathway for C-1 metabolism

  2. Recolonization of macrozoobenthos on defaunated sediments in a hypertrophic brackish lagoon: effects of sulfide removal and sediment grain size.

    Science.gov (United States)

    Kanaya, Gen

    2014-04-01

    Influences of sediment types on recolonization of estuarine macrozoobenthos were tested using enclosures in a hypertrophic lagoon. Three types of azoic sediment, sand (S), sulfide-rich mud (M), and mud removed of sulfide through iron addition (MFe), were set in field for 35 days during a hypoxic period. A total of 14 taxa including opportunistic polychaetes and amphipods occurred. Infaunal community in S treatment was characterized by highest diversity, total density and biomass, and population density of five dominant taxa, while those parameters were lowest in M treatment. Sulfide removal in MFe treatment achieved much higher density, biomass, and population densities of several taxa in the sediment. Multivariate analyses demonstrated that the established community structure was unique to each treatment. These imply that dissolved sulfide level as well as sediment grain size is a key determinant for the community composition and recolonization speed of early colonists in estuarine soft-bottom habitats. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Defense Coastal/Estuarine Research Program (DCERP)

    Science.gov (United States)

    2007-09-19

    activities, splash points and Landing Craft Air Cushion (LCAC) operations) and non-military Base activities (e.g., sewage treatment , storm water runoff and...We will measure the metabolism of benthic microalgae, the water column, eelgrass, and any dominant macroalgae by developing series of photosynthesis...activities (storm water control and sewage treatment ). Defense Coastal/Estuarine Research Program (DCERP) Research Plan DCERP Research Plan 32 September 19

  4. Sediment and contaminant transport in a marine environment

    International Nuclear Information System (INIS)

    Onishi, Y.; Thompson, F.L.

    1986-01-01

    The finite-element model FETRA is an unsteady, verically averaged two-dimensional model to simulate the transport of sediment and contaminants (radionuclides, heavy metals, pesticides, etc.) in coastal and estuarine water. The model, together with the hydrodynamic model CAFE-I, was applied to the Irish Sea to predict the migration and accumulation of sediment (both cohesive and noncohesive) and of a radionuclide (dissolved and sediment-sorbed) in a tide- and wind-driven system. The study demonstrated that FETRA is a useful tool for assessing sediment and toxic contaminant transport in a marine environment

  5. Abiotic characteristics and microalgal dynamics in South Africa's largest estuarine lake during a wet to dry transitional phase

    Science.gov (United States)

    Nunes, Monique; Adams, Janine B.; Bate, Guy C.; Bornman, Thomas G.

    2017-11-01

    The summer of 2012/2013 signified the end of the dry phase in the St Lucia estuarine system that lasted for over a decade. The increased rainfall coupled with the partial re-connection of the Mfolozi River to the estuarine system shifted St Lucia to a new limnetic state. With the increased availability of habitat due to the higher water level, it was expected that microalgal biomass and abundance would rapidly increase through recruitment from refuge areas i.e. South Lake and new introductions. Microalgal and physico-chemical data were collected at three sites within the Mfolozi/Msunduzi River and at 23 sites within the St Lucia estuarine system between June 2014 and February 2015. Results from this study indicated low biomass for both phytoplankton (<5 μg l-1) and microphytobenthos (<60 mg m-2) because of local and external drivers. These included limited nutrient and light availability, variable water residence times, biomass dilution and heterogeneity of the sediment. The high spatio-temporal variability limits the effectiveness of using the microalgal communities to detect change in the estuarine lake. In addition, significant intrasystem differences were observed between the three main lake basins and Narrows, due to the influence of the freshwater input from the Mfolozi River. This study provides insight into the spatio-temporal variability of physico-chemical conditions and microalgal communities during the 2014-2015 limnetic state.

  6. Mid-depth temperature maximum in an estuarine lake

    Science.gov (United States)

    Stepanenko, V. M.; Repina, I. A.; Artamonov, A. Yu; Gorin, S. L.; Lykossov, V. N.; Kulyamin, D. V.

    2018-03-01

    The mid-depth temperature maximum (TeM) was measured in an estuarine Bol’shoi Vilyui Lake (Kamchatka peninsula, Russia) in summer 2015. We applied 1D k-ɛ model LAKE to the case, and found it successfully simulating the phenomenon. We argue that the main prerequisite for mid-depth TeM development is a salinity increase below the freshwater mixed layer, sharp enough in order to increase the temperature with depth not to cause convective mixing and double diffusion there. Given that this condition is satisfied, the TeM magnitude is controlled by physical factors which we identified as: radiation absorption below the mixed layer, mixed-layer temperature dynamics, vertical heat conduction and water-sediments heat exchange. In addition to these, we formulate the mechanism of temperature maximum ‘pumping’, resulting from the phase shift between diurnal cycles of mixed-layer depth and temperature maximum magnitude. Based on the LAKE model results we quantify the contribution of the above listed mechanisms and find their individual significance highly sensitive to water turbidity. Relying on physical mechanisms identified we define environmental conditions favouring the summertime TeM development in salinity-stratified lakes as: small-mixed layer depth (roughly, ~wind and cloudless weather. We exemplify the effect of mixed-layer depth on TeM by a set of selected lakes.

  7. Nutrient Dynamics of Estuarine Invertebrates Are Shaped by Feeding Guild Rather than Seasonal River Flow.

    Directory of Open Access Journals (Sweden)

    Kelly Ortega-Cisneros

    Full Text Available This study aimed to determine the variability of carbon and nitrogen elemental content, stoichiometry and diet proportions of invertebrates in two sub-tropical estuaries in South Africa experiencing seasonal changes in rainfall and river inflow. The elemental ratios and stable isotopes of abiotic sources, zooplankton and macrozoobenthos taxa were analyzed over a dry/wet seasonal cycle. Nutrient content (C, N and stoichiometry of suspended particulate matter exhibited significant spatio-temporal variations in both estuaries, which were explained by the variability in river inflow. Sediment particulate matter (%C, %N and C:N was also influenced by the variability in river flow but to a lesser extent. The nutrient content and ratios of the analyzed invertebrates did not significantly vary among seasons with the exception of the copepod Pseudodiaptomus spp. (C:N and the tanaid Apseudes digitalis (%N, C:N. These changes did not track the seasonal variations of the suspended or sediment particulate matter. Our results suggest that invertebrates managed to maintain their stoichiometry independent of the seasonality in river flow. A significant variability in nitrogen content among estuarine invertebrates was recorded, with highest % N recorded from predators and lowest %N from detritivores. Due to the otherwise general lack of seasonal differences in elemental content and stoichiometry, feeding guild was a major factor shaping the nutrient dynamics of the estuarine invertebrates. The nutrient richer suspended particulate matter was the preferred food source over sediment particulate matter for most invertebrate consumers in many, but not all seasons. The most distinct preference for suspended POM as a food source was apparent from the temporarily open/closed system after the estuary had breached, highlighting the importance of river flow as a driver of invertebrate nutrient dynamics under extreme events conditions. Moreover, our data showed that

  8. Nutrient Dynamics of Estuarine Invertebrates Are Shaped by Feeding Guild Rather than Seasonal River Flow.

    Science.gov (United States)

    Ortega-Cisneros, Kelly; Scharler, Ursula M

    2015-01-01

    This study aimed to determine the variability of carbon and nitrogen elemental content, stoichiometry and diet proportions of invertebrates in two sub-tropical estuaries in South Africa experiencing seasonal changes in rainfall and river inflow. The elemental ratios and stable isotopes of abiotic sources, zooplankton and macrozoobenthos taxa were analyzed over a dry/wet seasonal cycle. Nutrient content (C, N) and stoichiometry of suspended particulate matter exhibited significant spatio-temporal variations in both estuaries, which were explained by the variability in river inflow. Sediment particulate matter (%C, %N and C:N) was also influenced by the variability in river flow but to a lesser extent. The nutrient content and ratios of the analyzed invertebrates did not significantly vary among seasons with the exception of the copepod Pseudodiaptomus spp. (C:N) and the tanaid Apseudes digitalis (%N, C:N). These changes did not track the seasonal variations of the suspended or sediment particulate matter. Our results suggest that invertebrates managed to maintain their stoichiometry independent of the seasonality in river flow. A significant variability in nitrogen content among estuarine invertebrates was recorded, with highest % N recorded from predators and lowest %N from detritivores. Due to the otherwise general lack of seasonal differences in elemental content and stoichiometry, feeding guild was a major factor shaping the nutrient dynamics of the estuarine invertebrates. The nutrient richer suspended particulate matter was the preferred food source over sediment particulate matter for most invertebrate consumers in many, but not all seasons. The most distinct preference for suspended POM as a food source was apparent from the temporarily open/closed system after the estuary had breached, highlighting the importance of river flow as a driver of invertebrate nutrient dynamics under extreme events conditions. Moreover, our data showed that estuarine

  9. How functional traits of estuarine macrobenthic assemblages respond to metal contamination?

    KAUST Repository

    Piló, D.

    2016-08-06

    The effects of metal contamination on estuarine macrobenthic communities were investigated using the Biological Traits Analysis (BTA). The study was carried out in the Tagus estuary (western Portugal). Samples of macrobenthic communities and associated environmental variables were taken in four surveys (September 2012, and February, May and October 2013) across the contamination gradient from three main zones: a slightly contaminated, a moderately contaminated and a highly contaminated zone. Functional traits for the most abundant species were assigned using seven categories based on “Feeding mode”, “Life span”, “Body size”, “Motility”, “Position in sediments”, “Larval type” and “AMBI ecological group”. To investigate whether the macroinvertebrate community structure was associated with the environmental parameters and biological traits an integrative multivariate analysis, combining the RLQ analysis and the fourth-corner method, was applied. Within this analysis, human-induced estuarine variables (metals) were rendered independent from natural ones (sediment fine particles) through partial correlations. Following this approach, it was possible to decouple the effects of two typically highly correlated environmental descriptors with different origins. Overall, the study identified significant relationships between sediment environmental descriptors and the functional traits of macrobenthic communities. Further, RLQ/Fourth-corner combined analysis successfully isolated the traits and corresponding species that were most correlated with the measured concentration of trace metals in sediments, supporting the knowledge that benthic organisms exhibit distinct responses to different levels of disturbance. A shift in species dominance occurred along the contamination gradient with epifaunal tolerant species with very small size, long life span, and crawling motility dominating the highest contaminated area. This area was also related with

  10. Part I, Introduction: Ecology and Regional Context of Tidal Wetlands in the San Francisco Bay National Estuarine Research Reserve

    Directory of Open Access Journals (Sweden)

    Matthew C. Ferner

    2011-12-01

    Full Text Available This two-part special issue reviews the basic ecology of tidal wetlands in the San Francisco Estuary. Several articles highlight the well-preserved tracts of historic tidal marsh found at China Camp State Park and Rush Ranch Open Space Preserve. These two protected areas serve as important reference sites for wetland restoration and conservation and also comprise San Francisco Bay National Estuarine Research Reserve (SF Bay NERR. SF Bay NERR is part of the National Oceanic and Atmospheric Administration’s nationwide network of 28 estuarine research reserves (http://www.nerrs.noaa.gov that all share common goals: (1 conducting standardized long-term monitoring, (2 supporting applied environmental research, (3 providing stewardship of estuarine natural resources, and (4 linking science with decision making in pursuit of effective solutions to coastal management problems.

  11. Airborne remote sensing of estuarine intertidal radionuclide concentrations

    International Nuclear Information System (INIS)

    Rainey, M.P.

    1999-08-01

    The ability to map industrial discharges through remote sensing provides a powerful tool in environmental monitoring. Radionuclide effluents have been discharged, under authorization, into the Irish Sea from BNFL (British Nuclear Fuels Pic.) sites at Sellafield and Springfields since 1952. The quantitative mapping of this anthropogenic radioactivity in estuarine intertidal zones is crucial for absolute interpretations of radionuclide transport. The spatial resolutions of traditional approaches e.g. point sampling and airborne gamma surveys are insufficient to support geomorphic interpretations of the fate of radionuclides in estuaries. The research presented in this thesis develops the use of airborne remote sensing to derive high-resolution synoptic data on the distribution of anthropogenic radionuclides in the intertidal areas of the Ribble Estuary, Lancashire, UK. From multidate surface sediment samples a significant relationship was identified between the Sellafield-derived 137 Cs and 241 Am and clay content (r 2 = 0.93 and 0.84 respectively). Detailed in situ, and laboratory, reflectance (0.4-2.5μm) experiments demonstrated that significant relationships exist between Airborne Thematic Mapper (ATM) simulated reflectance and intertidal sediment grain-size. The spectral influence of moisture on the reflectance characteristics of the intertidal area is also evident. This had substantial implications for the timing of airborne image acquisition. Low-tide Daedalus ATM imagery (Natural Environmental Research Council) was collected of the Ribble Estuary on May 30th 1997. Preprocessing and linear unmixing of the imagery allowed accurate sub-pixel determinations of sediment clay content distributions (r 2 = 0.81). Subsequently, the established relationships between 137 Cs and 241 Am and sediment grain-size enabled the radionuclide activity distributions across the entire intertidal area (92 km 2 ) to be mapped at a geomorphic scale (1.75 m). The accuracy of these maps

  12. Characterisation of the hydrology of an estuarine wetland

    Science.gov (United States)

    Hughes, Catherine E.; Binning, Philip; Willgoose, Garry R.

    1998-11-01

    The intertidal zone of estuarine wetlands is characterised by a transition from a saline marine environment to a freshwater environment with increasing distance from tidal streams. An experimental site has been established in an area of mangrove and salt marsh wetland in the Hunter River estuary, Australia, to characterise and provide data for a model of intertidal zone hydrology. The experimental site is designed to monitor water fluxes at a small scale (36 m). A weather station and groundwater monitoring wells have been installed and hydraulic head and tidal levels are monitored over a 10-week period along a short one-dimensional transect covering the transition between the tidal and freshwater systems. Soil properties have been determined in the laboratory and the field. A two-dimensional finite element model of the site was developed using SEEP/W to analyse saturated and unsaturated pore water movement. Modification of the water retention function to model crab hole macropores was found necessary to reproduce the observed aquifer response. Groundwater response to tidal fluctuations was observed to be almost uniform beyond the intertidal zone, due to the presence of highly permeable subsurface sediments below the less permeable surface sediments. Over the 36 m transect, tidal forcing was found to generate incoming fluxes in the order of 0.22 m 3/day per metre width of creek bank during dry periods, partially balanced by evaporative fluxes of about 0.13 m 3/day per metre width. During heavy rainfall periods, rainfall fluxes were about 0.61 m 3/day per metre width, dominating the water balance. Evapotranspiration rates were greater for the salt marsh dominated intertidal zone than the non-tidal zone. Hypersalinity and salt encrustation observed show that evapotranspiration fluxes are very important during non-rainfall periods and are believed to significantly influence salt concentration both in the surface soil matrix and the underlying aquifer.

  13. Turning the tide: estuarine bars and mutually evasive ebb- and flood-dominated channels

    Science.gov (United States)

    Kleinhans, M. G.; Leuven, J.; van der Vegt, M.; Baar, A. W.; Braat, L.; Bergsma, L.; Weisscher, S.

    2015-12-01

    Estuaries have perpetually changing and interacting channels and shoals formed by ebb and flood currents, but we lack a descriptive taxonomy and forecasting model. We explore the hypotheses that the great variation of bar and shoal morphologies are explained by similar factors as river bars, namely channel aspect ratio, sediment mobility and limits on bar erosion and chute cutoff caused by cohesive sediment. Here we use remote sensing data and a novel tidal flume setup, the Metronome, to create estuaries or short estuarine reaches from idealized initial conditions, with and without mud supply at the fluvial boundary. Bar width-depth ratios in estuaries are similar to those in braided rivers. In unconfined (cohesionless) experimental estuaries, bar- and channel dynamics increase with increasing river discharge. Ebb- and flood-dominated channels are ubiquitous even in entirely straight sections. The apparent stability of ebb- and flood channels is partly explained by the inherent instability of symmetrical channel bifurcations as in rivers.

  14. Distribution of tritium in estuarine waters: the role of organic matter

    Energy Technology Data Exchange (ETDEWEB)

    Turner, Andrew [Consolidated Radio-isotope Facility, School of Earth, Ocean and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA (United Kingdom)], E-mail: aturner@plymouth.ac.uk; Millward, Geoffrey E.; Stemp, Martin [Consolidated Radio-isotope Facility, School of Earth, Ocean and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA (United Kingdom)

    2009-10-15

    Tritium is an important environmental radionuclide whose reactivity with ligands and solids in aquatic systems is assumed to be limited. We studied the fractionation and sorption of tritium (added as tritiated water) in river water and seawater, and found that its distribution appears to be influenced by its affinity for organic matter. Tritium rapidly equilibrates with dissolved organic ligands that are retained by a reverse-phase C18 column, and with suspended sediment particles. Significantly, a measurable fraction of sorbed tritium associates with proteinaceous material that is potentially available to sediment-feeding organisms. These characteristics have not been reported previously and cannot be accounted for solely by isotopic exchange with hydrogen. Nevertheless, they are in qualitative agreement with available measurements of tritium in estuarine and coastal waters where its principal discharge is as tritiated water. Further research into the estuarine biogeochemical behaviour of tritium is required and radiological distribution coefficients and concentration factors that are assumed for this radionuclide may require reconsideration.

  15. Distribution of tritium in estuarine waters: the role of organic matter

    International Nuclear Information System (INIS)

    Turner, Andrew; Millward, Geoffrey E.; Stemp, Martin

    2009-01-01

    Tritium is an important environmental radionuclide whose reactivity with ligands and solids in aquatic systems is assumed to be limited. We studied the fractionation and sorption of tritium (added as tritiated water) in river water and seawater, and found that its distribution appears to be influenced by its affinity for organic matter. Tritium rapidly equilibrates with dissolved organic ligands that are retained by a reverse-phase C18 column, and with suspended sediment particles. Significantly, a measurable fraction of sorbed tritium associates with proteinaceous material that is potentially available to sediment-feeding organisms. These characteristics have not been reported previously and cannot be accounted for solely by isotopic exchange with hydrogen. Nevertheless, they are in qualitative agreement with available measurements of tritium in estuarine and coastal waters where its principal discharge is as tritiated water. Further research into the estuarine biogeochemical behaviour of tritium is required and radiological distribution coefficients and concentration factors that are assumed for this radionuclide may require reconsideration.

  16. Methylmercury decomposition in sediments and bacterial cultures: Involvement of methanogens and sulfate reducers in oxidative demethylation

    International Nuclear Information System (INIS)

    Oremland, R.S.; Culbertson, C.W.; Winfrey, M.R.

    1991-01-01

    The biogeochemical cycling of mercury has received considerable attention because of the toxicity of methylmercury, its bioaccumulation in biota, and its biomagnification in aquatic food chains. The formation of methylmercury is mediated primarily by microorganisms. Demethylation of monomethylmercury in freshwater and estuarine sediments and in bacterial cultures was investigated with 14 CH 3 HgI. Under anaerobiosis, results with inhibitors indicated partial involvement of both sulfate reducers and methanogens, the former dominated estuarine sediments, while both were active in freshwaters. Aerobes were the most significant demethylators in estuarine sediments, but were unimportant in freshwater sediments. Products of anaerobic demthylation were mainly 14 CO 2 as well as lesser amounts of 14 CH 4 . Acetogenic activity resulted in fixation of some 14 CO 2 produced from 14 CH 3 HgI into acetate. Aerobic demethylation in estuarine sediments produced only 14 CH 4 , while aerobic demethylation in freshwater sediments produced small amounts of both 14 CH 4 and 14 CO 2 . Two species of Desulfovibrio produced only traces of 14 CH 4 from 14 CH 3 HgI, while a culture of a methylotrophic methanogen formed traces of 14 CO 2 and 14 CH 4 when grown on trimethylamine in the presence of the 14 CH 3 HgI. These results indicate that both aerobes and anaerobes demethylate mercury in sediments, but that either group may dominate in a particular sediment type. Aerobic demethylation in the estuarine sediments appeared to proceed by the previously characterized organomercurial-lyase pathway, because methane was the sole product. This indicates the presence of an oxidative pathway, possibly one in which methylmercury serves as an analog of one-carbon substrates

  17. Toward Understanding the Dynamics of Microbial Communities in an Estuarine System

    KAUST Repository

    Zhang, Weipeng; Bougouffa, Salim; Wang, Yong; Lee, On On; Yang, Jiangke; Chan, Colin; Song, Xingyu; Qian, Pei-Yuan

    2014-01-01

    Community assembly theories such as species sorting theory provide a framework for understanding the structures and dynamics of local communities. The effect of theoretical mechanisms can vary with the scales of observation and effects of specific environmental factors. Based on 16S rRNA gene tag pyrosequencing, different structures and temporal succession patterns were discovered between the surface sediments and bottom water microbial communities in the Pearl River Estuary (PRE). The microbial communities in the surface sediment samples were more diverse than those in the bottom water samples, and several genera were specific for the water or sediment communities. Moreover, water temperature was identified as the main variable driving community dynamics and the microbial communities in the sediment showed a greater temporal change. We speculate that nutrient-based species sorting and bacterial plasticity to the temperature contribute to the variations observed between sediment and water communities in the PRE. This study provides a more comprehensive understanding of the microbial community structures in a highly dynamic estuarine system and sheds light on the applicability of ecological theoretical mechanisms.

  18. Toward understanding the dynamics of microbial communities in an estuarine system.

    Directory of Open Access Journals (Sweden)

    Weipeng Zhang

    Full Text Available Community assembly theories such as species sorting theory provide a framework for understanding the structures and dynamics of local communities. The effect of theoretical mechanisms can vary with the scales of observation and effects of specific environmental factors. Based on 16S rRNA gene tag pyrosequencing, different structures and temporal succession patterns were discovered between the surface sediments and bottom water microbial communities in the Pearl River Estuary (PRE. The microbial communities in the surface sediment samples were more diverse than those in the bottom water samples, and several genera were specific for the water or sediment communities. Moreover, water temperature was identified as the main variable driving community dynamics and the microbial communities in the sediment showed a greater temporal change. We speculate that nutrient-based species sorting and bacterial plasticity to the temperature contribute to the variations observed between sediment and water communities in the PRE. This study provides a more comprehensive understanding of the microbial community structures in a highly dynamic estuarine system and sheds light on the applicability of ecological theoretical mechanisms.

  19. Toward Understanding the Dynamics of Microbial Communities in an Estuarine System

    KAUST Repository

    Zhang, Weipeng

    2014-04-14

    Community assembly theories such as species sorting theory provide a framework for understanding the structures and dynamics of local communities. The effect of theoretical mechanisms can vary with the scales of observation and effects of specific environmental factors. Based on 16S rRNA gene tag pyrosequencing, different structures and temporal succession patterns were discovered between the surface sediments and bottom water microbial communities in the Pearl River Estuary (PRE). The microbial communities in the surface sediment samples were more diverse than those in the bottom water samples, and several genera were specific for the water or sediment communities. Moreover, water temperature was identified as the main variable driving community dynamics and the microbial communities in the sediment showed a greater temporal change. We speculate that nutrient-based species sorting and bacterial plasticity to the temperature contribute to the variations observed between sediment and water communities in the PRE. This study provides a more comprehensive understanding of the microbial community structures in a highly dynamic estuarine system and sheds light on the applicability of ecological theoretical mechanisms.

  20. Estuarine consumers utilize marine, estuarine and terrestrial organic matter and provide connectivity among these food webs

    Science.gov (United States)

    The flux of organic matter (OM) across ecosystem boundaries can influence estuarine food web dynamics and productivity. However, this process is seldom investigated taking into account all the adjacent ecosystems (e.g. ocean, river, land) and different hydrological settings (i.e....

  1. Optical dating of young tidal sediments in the Danish Wadden Sea

    DEFF Research Database (Denmark)

    Madsen, Anni Tindahl; Murray, A. S.; Andersen, Thorbjørn Joest

    2007-01-01

    reliable and reproducible results in cores from sub-, inter- and supra-tidal sediments, ranging from only a few years up to ~1000 years old, confirming its value in the estimation of estuarine accretion rates. With OSL it is, for the first time, possible to date sediment cores from silty and sandy tidal...... flats, providing a new approach to the problem of evaluation of stability and calculation of sediment budgets for estuaries and coastal lagoons....

  2. Acute and chronic toxicity of sediment samples from Guanabara Bay (RJ) during the rainy period

    OpenAIRE

    Maranho,Luciane Alves; Abreu,Ilene Matanó; Santelli,Ricardo Erthal; Cordeiro,Renato Campelo; Soares-Gomes,Abílio; Moreira,Lucas Buruaem; Morais,Rodofley Davino; Abessa,Denis Moledo de Sousa

    2010-01-01

    Guanabara Bay is a marine-estuarine environment of high ecological and socio-economic importance, subject to a variety of environmental impacts. Sediment is the eventual repository for most substances introduced into water bodies and may, therefore, provide an integrated measure of the environmental quality, which can be assessed by many different approaches. In this project, the quality of sediments from Guanabara Bay was evaluated by the ecotoxicological approach: whole-sediment toxicity te...

  3. 78 FR 50038 - National Estuarine Research Reserve System

    Science.gov (United States)

    2013-08-16

    ....33(c), the revised plan meets the reserve's requirements for compliance. The Wells Reserve Management... Reserve System AGENCY: Estuarine Reserves Division, Office of Ocean and Coastal Resource Management.... ACTION: Notice of Public Comment Period for the Wells, Maine National Estuarine Research Reserve...

  4. Circulation and suspended sediment dynamics in a tropical estuary under different morphological setting

    Directory of Open Access Journals (Sweden)

    BÁRBARA P. PAIVA

    2016-01-01

    Full Text Available ABSTRACT Estuarine processes are directly related to the interaction of its forcing conditions with the local morphology. In this study we assess the implications of the opening of a new inlet on the hydrodynamics and suspended sediment concentration (SSC. A set of physical parameters have been measured in the Itanhém river estuary, a small, shallow and mangrove fringed tropical estuary in Northeastern Brazil. Field surveys have been conducted in August 2007 and January 2008, separated by an important morphological change. Our observations show that even shortening the lower estuary channel in 2 km, the inlet opening did not imply in changes in the estuarine circulation. However, SSC increased after the inlet opening. General estuarine circulation showed synodical modulation of tidal asymmetry and residual suspended sediment transport. The estuary showed flood dominance at spring tide and ebb dominance at neap tide. Although not directly changing the estuarine hydrodynamics, the morphological change resulted in an important increase in SSC. This increase might be related to a facilitated import of inner shelf sediment through a shorter channel, having important implications for the estuarine sedimentation processes.

  5. Using a tiered approach based on ecotoxicological techniques to assess the ecological risks of contamination in a subtropical estuarine protected area.

    Science.gov (United States)

    Campos, B G; Cruz, A C F; Buruaem, L M; Rodrigues, A P C; Machado, W T V; Abessa, D M S

    2016-02-15

    This study sought to assess the ecological risks of sediments from the northern portion of an estuarine protected area (Cananéia-Iguape-Peruíbe Protected Area--CIP-PA). The CIP-PA is located on the southern coast of São Paulo State, Brazil and is influenced by former mining activities along the Ribeira de Iguape River (RIR). We used a tiered approach based on multiple lines of evidence (geochemical analyses, toxicity tests, and whole sediment toxicity identification and evaluation) in order to assess environmental quality. The sediments presented a heterogeneous composition, but the samples collected close to the RIR exhibited higher concentrations of metals (Cd, Cr, Cu, Pb) and toxicity. Multivariate analysis showed that toxicity was associated with metals, mud, organic matter, and CaCO3 quantities. The whole-sediment toxicity identification evaluation approach indicated that ammonia and metals were responsible for sediment toxicity. Overall, we concluded that the sediments collected at depositional areas from the northern portion of the CIP-PA presented high levels of metals, which originated from former mining areas located in the upper RIR basin, and that this contamination had toxic effects on aquatic invertebrates. The tiered approach was useful for identifying the degradation of sediment quality and also for indicating the causes of toxicity. Because the CIP-PA is an important estuarine protected area that is ecologically at risk, large-scale measures are required to control the sources of contamination.

  6. Impact of intertidal area characteristics on estuarine tidal hydrodynamics: A modelling study for the Scheldt Estuary

    Science.gov (United States)

    Stark, J.; Smolders, S.; Meire, P.; Temmerman, S.

    2017-11-01

    effects of tidal prism decrease upstream and tidal prism increase downstream of additional storage areas, our model results indicate a reduction in tidal prism far downstream of intertidal storage areas as a result of a decreasing tidal range. This study may assist estuarine managers in assessing the impact of marsh restoration and managed shoreline realignment projects, as well as with the morphological management of estuaries through dredging and disposal of sediment on intertidal areas.

  7. Impact evaluation of the liquid effluent disposal of the Duque de Caxias Refinery (REDUC) in fluvial waters and sediments, RJ, Brazil; Avaliacao do impacto do descarte de efluentes liquidos da Refinaria Duque de Caxias (REDUC) sobre aguas e sedimentos fluviais, RJ, Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Bidone, Edison Dausacker; Santelli, Ricardo Erthal; Cordeiro, Renato Campello [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil); Gamboa, Carla Maria; Camaz, Fernando Ribeiro; Jorge, Fabricio Goncalves [PETROBRAS/REDUC, Rio de Janeiro, RJ, RJ (Brazil). Refinaria de Duque de Caxias; Carvalho, Maria de Fatima B. [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES)

    2008-07-01

    The purpose of this work is to assess the contribution of the liquid effluents of the Duque de Caxias Refinery (REDUC) in the water and sediment contamination in the estuarine Iguacu-Sarapui system, a tributary of the Guanabara Bay, Rio de Janeiro, Brazil. Since 2002 is being conducted a quarterly monitoring of some parameters in water, river sediments and treated liquid effluent, such as: pH, suspended solids, total sedimented solids, dissolved oxygen, biochemical oxygen demand, chemical oxygen demand, total organic carbon, oil and grease (O and G), phenols, sulfide, ammonia, metals and metalloids (V, Cr, Pb, Ni, Cu, Cd, Zn, Hg, As, Se , Co, Fe, Mn), polycyclic aromatic hydrocarbons, coprostanol and cholesterol (indicators of domestic wastes). The obtained results show that the effluents meet the legal standards and the treated liquid effluents from REDUC in the estuarine system have little or no impact on river water quality. The higher levels of contaminants detected in water and sediments samples are directly related to untreated domestic sewage from urban areas. (author)

  8. Challenging paradigms in estuarine ecology and management

    Science.gov (United States)

    Elliott, M.; Whitfield, A. K.

    2011-10-01

    For many years, estuarine science has been the 'poor relation' in aquatic research - freshwater scientists ignored estuaries as they tended to get confused by salt and tides, and marine scientists were more preoccupied by large open systems. Estuaries were merely regarded by each group as either river mouths or sea inlets respectively. For the past four decades, however, estuaries (and other transitional waters) have been regarded as being ecosystems in their own right. Although often not termed as such, this has led to paradigms being generated to summarise estuarine structure and functioning and which relate to both the natural science and management of these systems. This paper defines, details and affirms these paradigms that can be grouped into those covering firstly the science (definitions, scales, linkages, productivity, tolerances and variability) and secondly the management (pressures, valuation, health and services) of estuaries. The more 'science' orientated paradigms incorporate the development and types of ecotones, the nature of stressed and variable systems (with specific reference to resilience and redundancy), the relationship between generalists and specialists produced by environmental tolerance, the relevance of scale in relation to functioning and connectivity, the sources of production and degree of productivity, the biodiversity-ecosystem functioning and the stress-subsidy debates. The more 'management' targeted paradigms include the development and effects of exogenic unmanaged pressures and endogenic managed pressures, the perception of health and the ability to manage estuaries (related to internal and external influences), and the influence of all of these on the production of ecosystem services and societal benefits.

  9. Ecotoxicology of bromoacetic acid on estuarine phytoplankton

    International Nuclear Information System (INIS)

    Gordon, Ana R.; Richardson, Tammi L.; Pinckney, James L.

    2015-01-01

    Bromoacetic acid is formed when effluent containing chlorine residuals react with humics in natural waters containing bromide. The objective of this research was to quantify the effects of bromoacetic acid on estuarine phytoplankton as a proxy for ecosystem productivity. Bioassays were used to measure the EC 50 for growth in cultured species and natural marine communities. Growth inhibition was estimated by changes in chlorophyll a concentrations measured by fluorometry and HPLC. The EC 50 s for cultured Thalassiosira pseudonana were 194 mg L −1 , 240 mg L −1 for Dunaliella tertiolecta and 209 mg L −1 for Rhodomonas salina. Natural phytoplankton communities were more sensitive to contamination with an EC 50 of 80 mg L −1 . Discriminant analysis suggested that bromoacetic acid additions cause an alteration of phytoplankton community structure with implications for higher trophic levels. A two-fold EC 50 decrease in mixed natural phytoplankton populations affirms the importance of field confirmation for establishing water quality criteria. - Highlights: • Bromoacetic acid exposure resulted in lethal impacts to estuarine phytoplankton. • Cultured phytoplankton were less sensitive to bromoacetic acid than natural communities. • Lab results should be confirmed with field experiments whenever possible. - The toxicology of haloacetic acids has been studied in freshwater ecosystems, and urbanization of the coastal zone is making effects in marine ecosystems equally relevant.

  10. Triclosan alterations of estuarine phytoplankton community structure.

    Science.gov (United States)

    Pinckney, James L; Thompson, Laura; Hylton, Sarah

    2017-06-15

    Antimicrobial additives in pharmaceutical and personal care products are a major environmental concern due to their potential ecological impacts on aquatic ecosystems. Triclosan (TCS) has been used as an antiseptic, disinfectant, and preservative in various media. The sublethal and lethal effects of TCS on estuarine phytoplankton community composition were investigated using bioassays of natural phytoplankton communities to measure phytoplankton responses to different concentrations of TCS ranging from 1 to 200μgl -1 . The EC 50 (the concentration of an inhibitor where the growth is reduced by half) for phytoplankton groups (diatoms, chlorophytes, cryptophytes) examined in this ranged from 10.7 to 113.8μg TCS l -1 . Exposures resulted in major shifts in phytoplankton community composition at concentrations as low as 1.0μg TCS l -1 . This study demonstrates estuarine ecosystem sensitivity to TCS exposure and highlights potential alterations in phytoplankton community composition at what are typically environmental concentrations of TCS in urbanized estuaries. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Impact of estuarine pollution on birds

    Science.gov (United States)

    Blus, L.J.; Wiemeyer, Stanley N.; Kerwin, J.A.; Stendell, R.C.; Ohlendorf, H.M.; Stickel, L.F.

    1977-01-01

    Pollution of estuaries affects bird populations indirectly through changes in habitat and food supply. The multi-factor pollution of Chesapeake Bay has resulted in diminution of submerged aquatic plants and consequent change in food habits of the canvasback duck. Although dredge-spoil operations can improve wildlife habitat, they often result in its demise. Pollution of estuaries also affects birds directly, through chemical toxication, which may result in outright mortality or in reproductive impairment. Lead from industrial sources and roadways enters the estuaries and is accumulated in tissues of birds. Lead pellets deposited in estuaries as a result of hunting are consumed by ducks with sufficient frequency .to result m large annual die-offs from lead poisoning. Fish in certain areas, usually near industrial sources, may contain levels of mercury high enough to be hazardous to birds that consume them. Other heavy metals are present in estuarine birds, but their significance is poorly known. Oil exerts lethal or sublethal effects on birds by oiling their feathers, oiling eggs and young by contaminated parents, and by ingestion of oil-contaminated food. Organochlorine chemicals, of both agricultural and industrial origin, travel through the food chains and reach harmful levels in susceptible species of birds in certain estuarine ecosystems. Both outright mortality and reproductive impairment have occurred.

  12. Sediment Trapping in Estuaries

    Science.gov (United States)

    Burchard, Hans; Schuttelaars, Henk M.; Ralston, David K.

    2018-01-01

    Estuarine turbidity maxima (ETMs) are generated by a large suite of hydrodynamic and sediment dynamic processes, leading to longitudinal convergence of cross-sectionally integrated and tidally averaged transport of cohesive and noncohesive suspended particulate matter (SPM). The relative importance of these processes for SPM trapping varies substantially among estuaries depending on topography, fluvial and tidal forcing, and SPM composition. The high-frequency dynamics of ETMs are constrained by interactions with the low-frequency dynamics of the bottom pool of easily erodible sediments. Here, we use a transport decomposition to present processes that lead to convergent SPM transport, and review trapping mechanisms that lead to ETMs at the landward limit of the salt intrusion, in the freshwater zone, at topographic transitions, and by lateral processes within the cross section. We use model simulations of example estuaries to demonstrate the complex concurrence of ETM formation mechanisms. We also discuss how changes in SPM trapping mechanisms, often caused by direct human interference, can lead to the generation of hyperturbid estuaries.

  13. Sediment toxicity assessment in the Lagoon of Venice (Italy) using Paracentrotus lividus (Echinodermata: Echinoidea) fertilization and embryo bioassays.

    Science.gov (United States)

    Volpi Ghirardini, A; Arizzi Novelli, A; Tagliapietra, D

    2005-09-01

    The capacity of two toxicity bioassays (fertilization and embryo toxicity tests) to discriminate sediment toxicity using the sea urchin Paracentrotus lividus was tested in five stations with different levels of pollution in the Lagoon of Venice. Two stations were located in estuarine sites, two in the industrial zone, and one in a site at the top of our quality gradient (reference). Elutriate was chosen as sediment matrix to assess the potential effects of bioavailable pollutants in the water column as a consequence of sediment resuspension (dredging and dumping, fishing gear, etc.). An experimental design based on Quality Assurance/Quality Control procedures (QA/QC) was adopted in order to set the methodological basis for an effective use of these bioassays in monitoring programs. Results revealed both higher embriotoxicity than spermiotoxicity in all stations and the efficacy of combined use of both toxicity bioassays in discriminating differing pollution/bioavailability between stations and periods. The good representativeness of the integrated sampling scheme and the standardization of all experimental phases yielded high precision of results. Clear Toxicity Fingerprints were evidenced for the investigated sites through the combined use of both bioassays. A good fit between ecotoxicological data and chemical contamination levels was found, except for unnatural sediment texture.

  14. Environmental characteristics of the Mandovi-Zuari estuarine system in Goa

    Science.gov (United States)

    Qasim, S. Z.; Sen Gupta, R.

    1981-11-01

    Two rivers, the Mandovi and the Zuari, with their interconnecting canal, form an estuarine system in Goa on the west coast of India. Physical, chemical and biological features of this estuary are adapted to a seasonal rhythm induced by the annual cycle of the monsoon. Heavy precipitation and land runoff from June to September bring about large changes in temperature, salinity, flow pattern, dissolved oxygen and nutrients when the estuary becomes freshwater dominated. The monsoon season (July-September) is followed by a recovery period during the post-monsoon season (October-January) and thereafter a stable period of the pre-monsoon season (February-May) when the estuary becomes marine dominated. During the pre-monsoon (dry) season, the water in the estuarine system remains well mixed and the intrusion of salt water is felt as far as 65 km upstream in both the rivers; but during the monsoon season the rivers become stratified and a salt wedge is formed in each river which extends up to about 10 km upstream in the Mandovi and 12 km in the Zuari. The flow of the estuarine system is regulated by the entry of seawater with the incoming tide through Zuari which reaches Mandovi through the canal. The flow is reversed during the outgoing tide when the estuarine system is flushed. Dilution factors in both the estuaries are similar and vary from 1·2 to 8; highest values occur during the pre-monsoon season. Two shoals/sand bars occur permanently in Mandovi (Aguada Bay) close to a ramp-like inlet to the sea. This inlet poses no navigational problems for about 9 months during the dry season; but for a 3-month period during the monsoon, the waterway becomes hazardous and is closed to boat traffic. Heavy swell and intense wave activity lead to the transfer of sediments into the navigational inlet and the calm season brings the materials back to their original position with practically no overall change in the bathymetry of the bay. The oxygen cycle in the estuarine system is

  15. Accumulation of heavy metals in sediments of marine environments along the southwest coast of India

    International Nuclear Information System (INIS)

    Manjunatha, B.R.; Yeats, P.A.; Smith, J.N.; Shankar, R.; Narayana, A.C.; Prakash, T.N.

    1999-01-01

    In order to estimate the rate of excessive sediment accumulation that causes navigational problems and the impacts of urban and industrial development on sediment quality, concentrations of Cu, Ni, Zn, Cr, Mn, Fe and Ca, and radioactivity levels of 210 Pb and 137 Cs have been measured in nineteen sediment cores from estuarine, lagoonal, marsh, backwater and inner shelf areas along the southwest coast of India. Sediment accumulation rates in estuarine, lagoonal, marshy areas of the Karnataka coast (ELMKC) and Cochin Backwaters (CBw) are three to six times higher than those in the adjacent inner shelf areas, consistent with the deposition of terrigenous sediments in the river-sea interaction zones. Hydrogen sulphide was detected in most of the samples; sediment colour varied from shades of gray to dark green. Sediments have lower elemental concentrations and element enrichment factors (EFs) particularly for redox sensitive elements such as Mn due to prevalence of reducing conditions in the sedimentary column. Sediments of ELMKC and CBw have a predominantly terrigenous source. They contain low Ca contents, characteristic of tropical river sediments. In contrast, a higher Ca content of inner shelf sediments off both Karnataka State (ISKS-1) and Kerala State (ISKS-2) implies the importance of additional sediment (CaCO 3 ) flux from the marine biota. Measured Cu, Ni and Zn concentrations are generally low, perhaps reflecting the pristine nature of sediments. However, higher concentrations of Cr at all stations and of Zn at CBw indicate the input of Cr enriched minerals like amphibole and pyroxene from the catchment as well as Zn from anthropogenic sources. Heavy metal accumulation rates are high in estuarine, lagoonal, marsh and backwater areas along the southwest coast of India. This is not only due to the proximity of sources, but also due to high sediment accumulation rates because of the reduction of river flow in river-sea interaction zones owing to particle

  16. Seafloor environments in the Long Island Sound estuarine system

    Science.gov (United States)

    Knebel, H.J.; Signell, R.P.; Rendigs, R. R.; Poppe, L.J.; List, J.H.

    1999-01-01

    broad areas of the basin floor in the western part of the Sound. The regional distribution of seafloor environments reflects fundamental differences in marine-geologic conditions between the eastern and western parts of the Sound. In the funnel-shaped eastern part, a gradient of strong tidal currents coupled with the net nontidal (estuarine) bottom drift produce a westward progression of environments ranging from erosion or nondeposition at the narrow entrance to the Sound, through an extensive area of bedload transport, to a peripheral zone of sediment sorting. In the generally broader western part of the Sound, a weak tidal-current regime combined with the production of particle aggregates by biologic or chemical processes, cause large areas of deposition that are locally interrupted by a patchy distribution of various other environments where the bottom currents are enhanced by and interact with the seafloor topography.

  17. Estuarine habitat quality reflects urbanization at large spatial scales in South Carolina's coastal zone.

    Science.gov (United States)

    Van Dolah, Robert F; Riekerk, George H M; Bergquist, Derk C; Felber, Jordan; Chestnut, David E; Holland, A Fredrick

    2008-02-01

    Land cover patterns were evaluated in 29 estuarine watersheds of South Carolina to determine relationships between urban/suburban development and estuarine habitat quality. Principal components analysis and Pearson product moment correlation analyses were used to examine the relationships between ten land cover categories and selected measures of nutrient or bacterial enrichment in the water column and contaminant enrichment in sediments. These analyses indicated strong relationships between land cover categories representing upland development and a composite measure of 24 inorganic and organic contaminants using the Effect Range Median-Quotient (ERM-Q). Similar relationships also were observed for the summed concentrations of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), pesticides, and metals. Data obtained from tidal creeks generally showed stronger correlations between urban/suburban land use and pesticides and metals compared to data obtained from larger open water habitats. Correlations between PAH concentrations and the urban/suburban land cover categories were similar between creek and open water habitats. PCB concentrations generally showed very little relationship to any of the land cover categories. Measures of nutrient enrichment, which included total Kjeldahl nitrogen (TKN), nitrate-nitrite, phosphorus, chlorophyll-a, and total organic carbon, were generally not significantly correlated with any land cover categories, whereas fecal coliform bacteria were significantly and positively correlated with the urban/suburban land cover categories and negatively correlated with the non-urban land cover categories. Fecal coliform correlations were stronger using data from the open water sites than from the tidal creek sites. Both ERM-Q and fecal coliform concentrations were much greater and more pervasive in watersheds with relatively high (>50%) urban/suburban cover compared to watersheds with low (urban/suburban cover. These

  18. Uptake, metabolism and sub-lethal effects of BDE-47 in two estuarine invertebrates with different trophic positions

    International Nuclear Information System (INIS)

    Díaz-Jaramillo, M.; Miglioranza, K.S.B.; Gonzalez, M.; Barón, E.; Monserrat, J.M.; Eljarrat, E.; Barceló, D.

    2016-01-01

    Two microcosm types -sediment-biota and biota-biota- were constructed to simulate different pathways of BDE-47 uptake, metabolism and oxidative stress effects in two key estuarine invertebrates (polychaete Laeonereis acuta and crab Cyrtograpsus angulatus). In the sediment-biota experiment, both species were exposed to spiked sediments; an environmentally reported and a high concentration of BDE-47 for 2 weeks. In the biota-biota experiment, crabs were fed with polychaetes pre-exposed to BDE-47 in the sediment-biota experiment. The sediment-biota experiment first revealed that polychaetes significantly accumulated BDE-47 (biota-sediment accumulation factor >2; p < 0.05) to a much greater extent than the crab organs (muscle, hepatopancreas, gills) at both sediment concentrations. For oxidative stress responses, polychaete and crab tissues exposed to spiked sediment showed a significant increase (p < 0.05) of only glutathione S-transferase (GST) activity with respect to controls in both BDE-47 concentrations. No lipid peroxidation (TBARS) or total antioxidant capacity (ACAP) changes were evident in the species or organs exposed to either BDE-47 sediment concentration. The biota-biota experiment showed that feeding crabs with pre-exposed polychaetes caused BDE-47 accumulation in organs as well as significant amounts of BDE-47 eliminated through feces (p < 0.05). Unlike the sediment-biota exposure, crabs fed with pre-exposed BDE-47 polychaetes showed the most conspicuous oxidative stress responses. Significant changes in GST and ACAP in both hepatopancreas and gills, in addition to enhanced TBARS levels in the hepatopancreas with respect to controls (p < 0.05), revealed that BDE-47 assimilated by invertebrates represents a potential source of toxicity to their predators. No methoxylated metabolites (MeO-PBDEs) were detected during BDE-47 metabolism in the invertebrates in either of the two different exposure types. In contrast, hydroxylated metabolites (OH

  19. Incorporation of Fine-Grained Sediment Erodibility Measurements into Sediment Transport Modeling, Capitol Lake, Washington

    Science.gov (United States)

    Stevens, Andrew W.; Gelfenbaum, Guy; Elias, Edwin; Jones, Craig

    2008-01-01

    Capitol Lake was created in 1951 with the construction of a concrete dam and control gate that prevented salt-water intrusion into the newly formed lake and regulated flow of the Deschutes River into southern Puget Sound. Physical processes associated with the former tidally dominated estuary were altered, and the dam structure itself likely caused an increase in retention of sediment flowing into the lake from the Deschutes River. Several efforts to manage sediment accumulation in the lake, including dredging and the construction of sediment traps upriver, failed to stop the lake from filling with sediment. The Deschutes Estuary Feasibility Study (DEFS) was carried out to evaluate the possibility of removing the dam and restoring estuarine processes as an alternative ongoing lake management. An important component of DEFS was the creation of a hydrodynamic and sediment transport model of the restored Deschutes Estuary. Results from model simulations indicated that estuarine processes would be restored under each of four restoration alternatives, and that over time, the restored estuary would have morphological features similar to the predam estuary. The model also predicted that after dam-removal, a large portion of the sediment eroded from the lake bottom would be deposited near the Port of Olympia and a marina located in lower Budd Inlet seaward of the present dam. The volume of sediment transported downstream was a critical piece of information that managers needed to estimate the total cost of the proposed restoration project. However, the ability of the model to predict the magnitude of sediment transport in general and, in particular, the volume of sediment deposition in the port and marina was limited by a lack of information on the erodibility of fine-grained sediments in Capitol Lake. Cores at several sites throughout Capitol Lake were collected between October 31 and November 1, 2007. The erodibility of sediments in the cores was later determined in the

  20. SPECIES INTERACTIONS BETWEEN ESTUARINE DETRITIVORES: INHIBITION OR FACILITATION?

    Science.gov (United States)

    Native Hawaiian estuarine detritivores; the prawn Macrobrachium grandimanus, and the neritid gastropod Neritina vespertina, were maintained in flow-through microcosms with conditioned leaves from two riparian tree species, Hau (Hibiscus tiliaceus) and guava (Psidium guajava). Th...

  1. GoM Coastal and Estuarine Biopsy Surveys

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Small vessel surveys are conducted within estuarine and nearshore coastal waters to collect tissue biopsy samples from bottlenose dolphins. Visual surveys are...

  2. Benthic foraminiferal biocoenoses in the estuarine regimes of Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Setty, M.G.A.P.

    Benthic Foraminifera are highly responsive to subtle changes in the estuarine environment. Keeping this in view, a qualitative analysis of living benthic Foraminifera was made of the samples collected from the Mandovi-Zuari estuaries...

  3. Shrimp farming in estuarine environment: Points to ponder

    Digital Repository Service at National Institute of Oceanography (India)

    Achuthankutty, C.T.

    of the expansion has taken place around the estuarine area as it facilitates water exchange and waste disposal. In semi-intensive and extensive type of farming practices, use of different types of chemicals and antibiotics, artificial feeds, probiotics...

  4. NOAA's Estuarine Living Marine Resources (ELMR) Data Base

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In 1985, NOAA launched the Estuarine Living Marine Resources (ELMR) Program to develop a consistent data base on the distribution, relative abundance, and life...

  5. Nutrient fluctuations in the Quatipuru river: A macrotidal estuarine mangrove system in the Brazilian Amazonian basin

    Science.gov (United States)

    Pamplona, Fábio Campos; Paes, Eduardo Tavares; Nepomuceno, Aguinaldo

    2013-11-01

    The temporal and spatial variability of dissolved inorganic nutrients (NO3-, NO2-, NH4+, PO43- and DSi), total nitrogen (TN), total phosphorus (TP), nutrient ratios, suspended particulate matter (SPM) and Chlorophyll-a (Chl-a) were evaluated for the macrotidal estuarine mangrove system of the Quatipuru river (QUATIES), east Amazon coast, North Brazil. Temporal variability was assessed by fortnightly sampling at a fixed station within the middle portion of the estuary, from November 2009 to November 2010. Spatial variability was investigated from two field surveys conducted in November 2009 (dry season) and May 2010 (rainy season), along the salinity gradient of the system. The average DIN (NO3- + NO2- + NH4+) concentration of 9 μM in the dry season was approximately threefold greater in comparison to the rainy season. NH4+ was the main form of DIN in the dry season, while NO3- predominated in the rainy season. The NH4+ concentrations in the water column during the dry season are largely attributed to release by tidal wash-out of the anoxic interstitial waters of the surficial mangrove sediments. On the other hand, the higher NO3- levels during the wet season, suggested that both freshwater inputs and nitrification processes in the water column acted in concert. The river PO43- concentrations (DIP mangrove forests also played a relevant role as a nutrient source as established by the high variability of the nutrient behaviour along the estuarine gradient, consequently affecting the productivity in QUATIES.

  6. Impact of boat generated waves over an estuarine intertidal zone of the Seine estuary (France)

    Science.gov (United States)

    Deloffre, Julien; Lafite, Robert

    2015-04-01

    Water movements in macrotidal estuaries are controlled by the tidal regime modulated seasonally by the fluvial discharge. Wind effect on hydrodynamics and sediment transport is also reported at the mouth. Besides estuaries are frequently man altered our knowledge on the human impact on hydrodynamics and sediment transport is less extended. As an example on the Seine estuary (France) port authorities have put emphasis on facilitating economic exchanges by means of embankment building and increased dredging activity over the last century. These developments led to secure sea vessel traffic in the Seine estuary but they also resulted in a change of estuarine hydrodynamics and sediment transport features. Consequences of boat generated waves are varied: increased water turbidity and sediment transfer, release of nutrient and contaminants in the water column, harmful to users, ecosystems and infrastructures generating important maintenance spending. The aim of this study is to analyse the impact of boat generated waves on sediment transport over an intertidal area. The studied site is located on the left bank in the fluvial part of the Seine estuary. On this site the maximum tidal range ranges between 1.25 and 3.5m respectively during neap and spring tide. The sampling strategy is based on continuous ADV acquisition at 4Hz coupled with turbidimeter and altimeter measurements (1 measurement every minute) in order to decipher sediment dynamics during one year. Our results indicate that sediment dynamics are controlled by river flow while medium term scale evolution is dependent on tidal range and short term dynamics on sea-vessels waves. 64% of boat passages generated significant sediment reworking (from few mm.min-1 to 3cm.min-1). This reworking rate is mainly controlled by two parameters: (i) water height on the site and (ii) vessels characteristics; in particular the distance between seabed and keel that generate a Bernoulli wave (with maximum amplitude of 0.6m

  7. Estuarine beaches of the Amazon coast: environmental and recreational characterization

    OpenAIRE

    de Sousa, Rosigleyse C.; Pereira, Luci Cajueiro Carneiro; Jiménez Quintana, José Antonio

    2016-01-01

    The Amazon coast is rich in natural resources, with highly valued natural landscapes and ecological systems. These environments include estuarine beaches, which are important areas for recreational activities. The present study provides an environmental and recreational diagnosis of three of these estuarine beaches on the Amazon coast (Colares, Maruda, and Murubira). The study was conducted in July, 2012, 2013 and 2015. An set of variables was assessed: (i) physical variables (hydrodynamics),...

  8. Characterization of Dredged Sediments from Santander Bay

    International Nuclear Information System (INIS)

    Cortes, M.; Ibanez, R.; Viguri, J.R.; Irabien, A.

    1999-01-01

    The purpose of this study is the physico- chemical characterisation of Santander Bay (North Spain) inter-tidal sediments, with the determination of levels of selected organic compounds pollution. A sampling strategy has been developed based on characteristic parameters of the study. The physico-chemical seasonal characterisation of sediments has been performed by determination of waster content, Ph, density, humidity, lost on ignition (LOI), particle size distribution, and chemical analysis of three categories of organic compounds (VOCs,EOX and PAHs) selected for its ubiquity, persistence and high potential of environmental hazard. The EOX analysis give a picture of the total load of organo halogen compounds in the estuarine area and the VOC and ph values obtained, allow the characterization of sediments in two areas in function of the closeness to the urban and industrial activities

  9. Redistribution of sewage-nitrogen in estuarine food webs following sewage treatment upgrades

    International Nuclear Information System (INIS)

    Pitt, Kylie A.; Connolly, Rod M.; Maxwell, Paul

    2009-01-01

    Stable nitrogen isotopes were used to assess the effects of wastewater treatment plant (WWTP) upgrades on the utilisation of sewage-N by estuarine biota in Moreton Bay, Australia. We measured δ 15 N of filamentous algae, mangrove leaves and shore crabs at the Brisbane and Logan Rivers before and after scheduled WWTP upgrades, and at two reference rivers where WWTPs had been upgraded >4 years previously. The total N discharged into Brisbane River decreased by >80% after the upgrades had occurred, but N loads remained similar at Logan River despite the upgrade. In Brisbane River, δ 15 N values of algae and crabs decreased and were comparable to the reference rivers within 1-2 years but no changes occurred at Logan River. The δ 15 N of mangrove leaves remained elevated in all rivers, indicating that sewage-N remained a major source to mangroves either from residual WWTP discharges or from N accumulated in the sediments over many years.

  10. A bacterial community-based index to assess the ecological status of estuarine and coastal environments

    KAUST Repository

    Aylagas, Eva

    2016-10-23

    Biotic indices for monitoring marine ecosystems are mostly based on the analysis of benthic macroinvertebrate communities. Due to their high sensitivity to pollution and fast response to environmental changes, bacterial assemblages could complement the information provided by benthic metazoan communities as indicators of human-induced impacts, but so far, this biological component has not been well explored for this purpose. Here we performed 16S rRNA gene amplicon sequencing to analyze the bacterial assemblage composition of 51 estuarine and coastal stations characterized by different environmental conditions and human-derived pressures. Using the relative abundance of putative indicator bacterial taxa, we developed a biotic index that is significantly correlated with a sediment quality index calculated on the basis of organic and inorganic compound concentrations. This new index based on bacterial assemblage composition can be a sensitive tool for providing a fast environmental assessment and allow a more comprehensive integrative ecosystem approach for environmental management. © 2016.

  11. An artificial water body provides habitat for an endangered estuarine seahorse species

    Science.gov (United States)

    Claassens, Louw

    2016-10-01

    Anthropogenic development, especially the transformation of natural habitats to artificial, is a growing concern within estuaries and coastal areas worldwide. Thesen Islands marina, an artificial water body, added 25 ha of new estuarine habitat to the Knysna Estuary in South Africa, home to the Knysna seahorse. This study aimed to answer: (I) Can an artificial water body provide suitable habitat for an endangered seahorse species? And if so (II) what characteristics of this new habitat are important in terms of seahorse utilization? Four major habitat types were identified within the marina canals: (I) artificial reno mattress (wire baskets filled with rocks); (II) Codium tenue beds; (III) mixed vegetation on sediment; and (IV) barren canal floor. Seahorses were found throughout the marina system with significantly higher densities within the reno mattress habitat. The artificial water body, therefore, has provided suitable habitat for Hippocampus capensis, a noteworthy finding in the current environment of coastal development and the increasing shift from natural to artificial.

  12. Determination of Cd, Pb, Zn and Cu in Sediment Compartments by Sequential Extraction and Isotope Dilution Inductively Coupled Plasma Mass Spectrometry (ID-ICP-MS

    Directory of Open Access Journals (Sweden)

    Gardolinski Paulo C. F. C.

    2002-01-01

    Full Text Available Trace concentrations of Cd, Cu, Pb and Zn in four different sediment fractions extracted in sequence were determined by isotope dilution inductively coupled mass spectrometry (IDICPMS. The metals from each fraction were extracted following the sequential extraction procedure recommended by the Bureau Commun de Référence (BCR of the Commission of the European Communities. As an alternative to external calibration, the elements were quantified by spiking the extracted solutions with 112Cd, 63Cu, 208Pb and 66Zn and application of isotope dilution. The proposed approach was applied to a sample collected from a lake and two standard reference materials, NIST2704 river sediment from the National Institute of Standards & Technology and the BCR-277 estuarine sediment. Detection limits, for each extracted solution, varied from 0.31 to 0.53 mug L¹ for Cd, 0.92 to 2.9 mug L¹ for Cu, 0.22 to 1.1 mug L¹ for Pb and 1.3 to 7.6 mug L¹ for Zn. The sum of the metals concentration in the different fractions was compatible with 95% confidence level found amounts obtained with complete digestion of the samples and with the certified values of the standard reference materials.

  13. ASSESSMENT OF POSSIBLE INDIRECT RISK OF NATURALLY OCCURING MERCURY AND CADMIUM THROUGH Mugil Sp. AND Geloina sp. CONSUMPTION IN SEGARA ANAKAN ESTUARINE ECOSYSTEM

    Directory of Open Access Journals (Sweden)

    Sri Noegrohati

    2010-06-01

    Full Text Available Estuarine ecosystem of Segara Anakan is located in south coast of Central Java, shielded from Indian Ocean by Nusakambangan island. The ecosystem of Segara Anakan estuary, Central Java, Indonesia, is influenced by fresh water inflow from Citanduy river basin and Indian sea water mostly by tidal actions through the western opening. The runoff materials continuously entering Segara Anakan from Citanduy catchment area, which geologically consist of weathering products of quarternary volcanic rocks from Galunggung mountain, West Java. Therefore various natural heavy metal contaminants are bound to the estuarine sediments, redistributed and accumulated within the ecosystem. In the present work, the effects of environmental stresses to mercury and cadmium abiotic distribution, and their availability to biotic ecosystems were studied, and consumers indirect risk assesment was carried out. In the laboratory scale studies on the distribution of mercury and cadmium in an estuarine simulation of water-field sediment, it was observed that the metal distribution coefficient decreases as the salinity and the acidity of the medium increases. Monitoring results confirmed that the highest levels of Hg and Cd in water and sediment samples were obtained in dry season. Consequently, the highest levels of Hg and Cd in biotic ecosystem, represented by Mugil sp. and Geloina sp., also obtained in dry season. The body burden of Hg in people of Segara Anakan villages, as indicated by the levels in hair and mother milk samples, taken at the end of the study (dry season 2004, were relatively low, but the levels of Cd in mother milk samples were significantly higher than that of control samples of Jogyakarta (P = 0.05. Consequently, the risk quotient for babies were exceeding the FAO/WHO PTWI. Based on the risk assessment carried out for babies and adults, at the present time it is advisable to consume Mugil sp. and Geloina sp., taken in wet season only and not in dry

  14. Trace element distribution in different chemical fractions of False Bay sediments

    International Nuclear Information System (INIS)

    Rosental, R.

    1984-05-01

    Trace metals in the aquatic environment are generally concentrated on solid geochemical phases which eventually become incorporated into estuarine and marine sediments. The mechanism of trace metal concentration is believed to be adsorption on various geochemical phases, such as hydrous metal oxides, clays and organic matter. Metals in estuarine sediments can thus be expected to be partitioned between different phases, depending on the concentration of the phase and the strength of the adsorption bond. The bioavailability of sediment-bound metals to deposit-feeding organisms will depend on trace metal partitioning and the kinetics of biological metal uptake from each geochemical phase. The major objective of this study was to establish an analytical procedure involving sequential chemical extractions for the partitioning of particulate trace metals in sediment samples, collected from False Bay. Eight metals were examined, i.e. Cd, Cu, Cr, Fe, Mn, Ni, Pb and Zn. X-ray diffraction was also used in the study

  15. Development of a chronic sediment toxicity test for marine benthic amphipods

    International Nuclear Information System (INIS)

    DeWitt, T.H.; Redmond, M.S.; Sewall, J.E.; Swartz, R.C.

    1992-12-01

    The results of the research effort culminated in the development of a research method for assessing the chronic toxicity of contaminated marine and estuarine sediments using the benthic amphipod, Leptocheirus plumulosus. The first chapter describes the efforts at collecting, handling, and culturing four estuarine amphipods from Chesapeake Bay, including L. plumulosus. This chapter includes maps of the distribution and abundance of these amphipods within Chesapeake Bay and methodologies for establishing cultures of amphipods which could be readily adopted by other laboratories. The second chapter reports the development of acute and chronic sediment toxicity test methods for L. plumulosus, its sensitivity to non-contaminant environmental variables, cadmium, two polynuclear aromatic hydrocarbons, and contaminated sediment from Baltimore Harbor, MD. The third chapter reports the authors attempts to develop a chronic sediment toxicity test with Ampelisca abdita

  16. Changes in N cycling induced by Ulva detritus enrichment of sediments

    DEFF Research Database (Denmark)

    Garcia-Robledo, Emilio; Revsbech, Niels Peter; Risgaard-Petersen, Nils

    2013-01-01

    Macroalgal accumulation and decomposition in shallow water environments typically result in an increase in the organic matter content of the sediment, affecting both benthic metabolism and nutrient dynamics. The present study investigates how a pulse addition of Ulva detritus to estuarine sedimen...

  17. Gamma-spectrometric analysis of river sediments collected around phosphate fertilizer industries

    International Nuclear Information System (INIS)

    Gallardo, M.C.; Garcia-Leon, M.; Mundi, M.; Respaldiza, M.A.

    1993-01-01

    Gamma-ray spectrometric analysis has been carried out on sediments collected in an estuarine system formed by two major rivers in southern Spain. The results show clearly that important amounts of natural radioactivity are accumulating on the bed of both rivers. This radioactivity appears to originate from effluent from several phoshate fertilizer factories adjacent to the estuary. (author)

  18. Development of acute and chronic sediment bioassays with the harpacticoid copepod Quinquelaophonte sp.

    Science.gov (United States)

    Stringer, Tristan J; Glover, Chris N; Keesing, Vaughan; Northcott, Grant L; Gaw, Sally; Tremblay, Louis A

    2014-01-01

    Reliable environmentally realistic bioassay methodologies are increasingly needed to assess the effects of environmental pollution. This study describes two estuarine sediment bioassays, one acute (96 h) and one chronic (14 d), with the New Zealand harpacticoid copepod Quinquelaophonte sp. utilising behavioural and reproductive endpoints. Spiked sediments were used to expose Quinquelaophonte sp. to three reference compounds representing important categories of estuarine chemical stressors: zinc (a metal), atrazine (a pesticide), and phenanthrene (a polycyclic aromatic hydrocarbon). Acute-to-chronic ratios (ACR) were used to further characterise species responses. Acute sediment (sandy and low total organic content) 96 h EC50 values for the sublethal inhibition of mobility for zinc, atrazine and phenanthrene were 137, 5.4, and 2.6 µg/g, respectively. The chronic EC50 values for inhibition of reproduction (total offspring) were 54.5, 0.0083, and 0.067 µg/g for zinc, atrazine, and phenanthrene, respectively. For phenanthrene, a potentially novel mode of action was identified on reproduction. Quinquelaophonte sp. was found to be more sensitive than several other estuarine species indicating choice of test organism is important to characterising the effects of environmentally relevant levels of contamination. The bioassay sediment results demonstrate the sensitivity and suitability of Quinquelaophonte sp. as a tool for the assessment use of estuarine health. © 2013 Published by Elsevier Inc.

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

    Digital Repository Service at National Institute of Oceanography (India)

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

    the mobility of arsenic complexes in an estuarine system. The higher salt (NaCl) concentrations result in less arsenic adsorption to the sediment due to formation of weak arsenic complexes because of competition from Cl sup(-) ions or due to a reduction...

  20. Feedback between residual circulations and sediment distribution in highly turbid estuaries: an analytical model

    NARCIS (Netherlands)

    Talke, S.A.|info:eu-repo/dai/nl/304823554; de Swart, H.E.|info:eu-repo/dai/nl/073449725; Schuttelaars, H.|info:eu-repo/dai/nl/164035656

    2009-01-01

    Motivated by field studies of the Ems estuary which show longitudinal gradients in bottom sediment concentration as high as O(0.01 kg/m4), we develop an analytical model for estuarine residual circulation based on currents from salinity gradients, turbidity gradients, and freshwater discharge.

  1. Investigating arsenic speciation and mobilization in sediments with DGT and DET

    DEFF Research Database (Denmark)

    Bennett, William W.; Teasdale, Peter R.; Panther, Jared G.

    2012-01-01

    Mobilization of arsenic from freshwater and estuarine sediments during the transition from oxic to anoxic conditions was investigated using recently developed diffusive sampling techniques. Arsenic speciation and Fe(II) concentrations were measured at high resolution (1-3 mm) with in situ diffusi...

  2. Anomalous behaviour of uranium isotopes in backwater sediments of Zuari river

    Digital Repository Service at National Institute of Oceanography (India)

    Joshi, L.U; Zingde, M.D.; Abidi, S

    The surface leaching of the labile component of uranium has been carried out in estuarine sediments of Zuari River in Goa, India The measurements of alpha activities of sup(238) U, sup(235) U and sup(234) U in the leachates indicated a remarkable...

  3. EFFECTS OF ON-BOTTOM OYSTER MARICULTURE ON SMALL, SEDIMENT-DWELLING INVERTEBRATES

    Science.gov (United States)

    As part of a programmatic effort to determine estuarine habitat values for ecological risk assessments, quantitative field studies of small ( 0.5 mm), sediment-dwelling invertebrates were conducted in Willapa Bay, WA in July 1998 and Tillamook Bay, OR in July 1999. The six habit...

  4. OYSTER GROUNDS, A SUPERIOR HABITAT FOR SMALL, SEDIMENT-DWELLING INVERTEBRATES

    Science.gov (United States)

    As part of a programmatic effort to determine estuarine habitat values for ecological risk assessments, quantitative field studies of small, sediment-dwelling invertebrates were conducted in Willapa Bay, WA in July 1998 and Tillamook Bay, OR in July 1999. The six habitats includ...

  5. Evidence for the preservation of technogenic tritiated organic compounds in an estuarine sedimentary environment.

    Science.gov (United States)

    Croudace, Ian W; Warwick, Phillip E; Morris, Jenny E

    2012-06-05

    The macrotidal Severn Estuary (southwestern UK) has received a broad range of industrial discharges since the beginning of the Industrial Revolution. A more recent anthropogenic input to the estuary has been technogenic tritium (specifically organically bound tritium, OBT). This was derived from a specialized industrial laboratory producing custom radiolabeled compounds for life science research and diagnostic testing from 1980 until 2008. While it was generally acknowledged that the radiological impact of the tritium discharges into the Estuary was small, public concern motivated the company and regulatory agencies to commission several research studies from 1998 to 2005 to better understand their environmental impact. This study examined OBT interaction with estuarine sediment by acquiring a broad range of geochemical and sedimentological data from a suite of sediment cores collected from the northern side of the Estuary. Two important observations are that the OBT compounds are strongly bound to the clay/silt fraction of sediment and that the down-core OBT profiles in intertidal and subtidal sediments are broadly similar to the discharge record. Geochemical and chronometric methods (Cu, Pb and Zn elemental profiles, (210)Pb, (137)Cs) provide important corroboration of the OBT record. A key additional piece of evidence that firmly authenticated the established chronology was the discovery of a previously unreported sedimentary marker layer that was generated by a major storm surge that occurred on December 13, 1981. Although this study has provided clear evidence of systematic accumulation of OBT in sedimentary sinks of the region, an estimation of its depositional inventory shows it represents only a small fraction of the total discharge. This modest retention in the principal sedimentary sinks of the Severn Estuary system reflects the particular dynamics of this highly macrotidal sediment starved estuary.

  6. Nitrate levels modulate denitrification activity in tropical mangrove sediments (Goa, India)

    Digital Repository Service at National Institute of Oceanography (India)

    Fernandes, S.O.; LokaBharathi, P.A.

    .M., & Bundrick, C.M. (1998). Potential sediment denitrification rates in estuaries of Northern Gulf of Mexico. Journal of environmental quality, 27(4), 859-868. Gruber, N., & Sarmiento, J.L. (1997). Global. Biogeochemical Cycles, 11, 235-266. Hahndel, R... of inorganic nitrogen in mangrove sediments (Terminos Lagoon, Mexico). Limnology and Oceanography, 41, 284-296. Sardessai, S. (1993). Dissolved, particulate and sedimentary humic acids in the mangroves and estuarine ecosystem of Goa, west coast of India...

  7. Composition of estuarine colloidal material: organic components

    Science.gov (United States)

    Sigleo, A.C.; Hoering, T.C.; Helz, G.R.

    1982-01-01

    Colloidal material in the size range 1.2 nm to 0.4 ??m was isolated by ultrafiltration from Chesapeake Bay and Patuxent River waters (U.S.A.). Temperature controlled, stepwise pyrolysis of the freeze-dried material, followed by gas chromatographic-mass spectrometric analyses of the volatile products indicates that the primary organic components of this polymer are carbohydrates and peptides. The major pyrolysis products at the 450??C step are acetic acid, furaldehydes, furoic acid, furanmethanol, diones and lactones characteristic of carbohydrate thermal decomposition. Pyrroles, pyridines, amides and indole (protein derivatives) become more prevalent and dominate the product yield at the 600??C pyrolysis step. Olefins and saturated hydrocarbons, originating from fatty acids, are present only in minor amounts. These results are consistent with the composition of Chesapeake phytoplankton (approximately 50% protein, 30% carbohydrate, 10% lipid and 10% nucleotides by dry weight). The pyrolysis of a cultured phytoplankton and natural particulate samples produced similar oxygen and nitrogencontaining compounds, although the proportions of some components differ relative to the colloidal fraction. There were no lignin derivatives indicative of terrestrial plant detritus in any of these samples. The data suggest that aquatic microorganisms, rather than terrestrial plants, are the dominant source of colloidal organic material in these river and estuarine surface waters. ?? 1982.

  8. Ecotoxicology of bromoacetic acid on estuarine phytoplankton.

    Science.gov (United States)

    Gordon, Ana R; Richardson, Tammi L; Pinckney, James L

    2015-11-01

    Bromoacetic acid is formed when effluent containing chlorine residuals react with humics in natural waters containing bromide. The objective of this research was to quantify the effects of bromoacetic acid on estuarine phytoplankton as a proxy for ecosystem productivity. Bioassays were used to measure the EC50 for growth in cultured species and natural marine communities. Growth inhibition was estimated by changes in chlorophyll a concentrations measured by fluorometry and HPLC. The EC50s for cultured Thalassiosira pseudonana were 194 mg L(-1), 240 mg L(-1) for Dunaliella tertiolecta and 209 mg L(-1) for Rhodomonas salina. Natural phytoplankton communities were more sensitive to contamination with an EC50 of 80 mg L(-1). Discriminant analysis suggested that bromoacetic acid additions cause an alteration of phytoplankton community structure with implications for higher trophic levels. A two-fold EC50 decrease in mixed natural phytoplankton populations affirms the importance of field confirmation for establishing water quality criteria. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. A user's guide to coping with estuarine management bureaucracy: An Estuarine Planning Support System (EPSS) tool.

    Science.gov (United States)

    Lonsdale, Jemma; Nicholson, Rose; Weston, Keith; Elliott, Michael; Birchenough, Andrew; Sühring, Roxana

    2018-02-01

    Estuaries are amongst the most socio-economically and ecologically important environments however, due to competing and conflicting demands, management is often challenging with a complex legislative framework managed by multiple agencies. To facilitate the understanding of this legislative framework, we have developed a GISbased Estuarine Planning Support System tool. The tool integrates the requirements of the relevant legislation and provides a basis for assessing the current environmental state of an estuary as well as informing and assessing new plans to ensure a healthy estuarine state. The tool ensures that the information is easily accessible for regulators, managers, developers and the public. The tool is intended to be adaptable, but is assessed using the Humber Estuary, United Kingdom as a case study area. The successful application of the tool for complex socio-economic and environmental systems demonstrates that the tool can efficiently guide users through the complex requirements needed to support sustainable development. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  10. The role of river flow and tidal asymmetry on 1-D estuarine morphodynamics

    NARCIS (Netherlands)

    Guo, L.; Van der Wegen, M.; Roelvink, J.A.; He, Q.

    2014-01-01

    Numerous research efforts have been devoted to understanding estuarine morphodynamics under tidal forcing. However, the impact of river discharge on estuarine morphodynamics is insufficiently examined. Inspired by the Yangtze Estuary, this work explores the morphodynamic impact of river discharge in

  11. Studies on growth and age of bivalves from temperate and tropical estuarine ecosystems

    Digital Repository Service at National Institute of Oceanography (India)

    Parulekar, A.H.

    Comparison of growth progression and age composition of Abra alba and Nuculana minuta from temperate estuarine ecosystem with Meretrix casta and Paphia malabarica from tropical estuarine environment, revealed that the annual growth rate in tropical...

  12. Reversing tidal flow and estuarine morphodynamics in the Metronome laboratory flume

    NARCIS (Netherlands)

    Kleinhans, M.G.; Leuven, J.R.F.W.; Braat, L.; van der Vegt, M.; van Maarseveen, M.C.G.; Markies, H.; Roosendaal, C.; van Eijk, A.M.

    2016-01-01

    Our objective is to test a novel experimental principle for creating reversing tidal flows of sufficient strength to cause estuarine morphodynamics. The study of estuarine morphodynamics has hitherto been limited to field observation and numerical modelling, whilst fluvial morphodynamics have

  13. Distribution and diversity of copepods in the Mandovi-Zuari estuarine system, Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Goswami, S.C.

    Truly estuarine and estuarine-marine species were the major components of copepods Neritic and limnetic species were stragglers in this environment and showed fortuitous distribution Monsoonal cycle induced seasonal rhythm on salinity and copepods...

  14. The role of bio-physical cohesive substrates on sediment winnowing and bedform development

    Science.gov (United States)

    Ye, Leiping; Parsons, Daniel; Manning, Andrew

    2017-04-01

    Existing sediment transport and bedform size predictions for natural open-channel flows in many environments are seriously impeded by a lack of process-based knowledge concerning the dynamics of complex bed sediment mixtures comprising cohesionless sand and biologically-active cohesive muds. A series of flume experiments (14 experimental runs) with different substrate mixtures of sand-clay-EPS (Extracellular Polymeric Substance) are combined with a detailed estuarine field survey (Dee estuary, NW England) to investigate the development of bedform morphologies and characteristics of suspended sediment over bio-physical cohesive substrates. The experimental results indicate that winnowing and sediment sorting can occur pervasively in bio-physical cohesive sediment - flow systems. Importantly however, the evolution of the bed and bedform dynamics, and hence turbulence production, is significantly reduced as bed substrate cohesivity increases. The estuarine subtidal zone survey also revealed that the bio-physical cohesion provided by both the clay and microorganism fractions in the bed plays a significant role in controlling the interactions between bed substrate and sediment suspension, deposition and bedform generation. The work will be presented here concludes by outlining the need to extend and revisit the effects of cohesivity in morphodynamic systems and the sets of parameters presently used in numerical modelling, particularly in the context of the impact of climate change on estuarine and coastal systems.

  15. Assessment of Trace Metals Contamination of Surface Water and Sediment: A Case Study of Mvudi River, South Africa

    Directory of Open Access Journals (Sweden)

    Joshua N. Edokpayi

    2016-02-01

    Full Text Available Trace metals contamination of rivers and sediments remains a global threat to biodiversity and humans. This study was carried out to assess the variation pattern in trace metals contamination in Mvudi River water and sediments for the period of January–June 2014. Metal concentrations were analyzed using an inductively-coupled plasma optical emission spectrometer after nitric acid digestion. A compliance study for the water samples was performed using the guidelines of the Department of Water Affairs and Forestry (DWAF of South Africa and the World Health Organization (WHO. The National Oceanic and Atmospheric Administration (NOAA sediment quality guidelines for marine and estuarine sediments and the Canadian Council of Ministers of the Environment sediment guidelines (CCME for freshwater sediments were used to determine the possible toxic effects of the metals on aquatic organisms. pH (7.2–7.7 and conductivity (10.5–16.1 mS/m values complied with DWAF and WHO standards for domestic water use. Turbidity values in nephelometric turbidity units (NTU were in the range of 1.9–429 and exceeded the guideline values. The monthly average levels of trace metals in the water and sediments of Mvudi River were in the range of: Al (1.01–9.644 mg/L and 4296–5557 mg/kg, Cd (0.0003–0.002 mg/L and from below the detection limit to 2.19 mg/kg, Cr (0.015–0.357 mg/L and 44.23–149.52 mg/kg, Cu (0.024–0.185 mg/L and 13.22–1027 mg/kg, Fe (0.702–2.645 mg/L and 3840–6982 mg/kg, Mn (0.081–0.521 mg/L and 279–1638 mg/kg, Pb (0.002–0.042 mg/L and 1.775-4.157 mg/kg and Zn (0.031–0.261 mg/L and 14.481–39.88 mg/kg. The average concentrations of Al, Cr, Fe, Mn and Pb in the water samples exceeded the recommended guidelines of DWAF and WHO for domestic water use. High concentrations of Al and Fe were determined in the sediment samples. Generally, the concentrations of Cd, Cr and Cu in the sediments exceeded the corresponding effect range low

  16. Foraminifera and Thecamoebians as hydrodynamic indicators for Amazon estuarine system

    Science.gov (United States)

    Laut, L. L.; Figueiredo, A. G.; Santos, V. F.; Souza-Vieira, S.

    2007-05-01

    The Amazon mangrove forest in Brazilian territory is one of the most extended in the world. It goes from Ponta do Tubarao (4S e 43W) to Cape Orange (5N e 51W) along 2,250 km of coast line. Because the Amazon River System influence, it can be divided into two regions; one with river influence toward north and the other without river influence. In order to characterize the mangrove environment hydrodynamic on both sides of the Amazon River System, foraminifera and thecamoebians assemblages were investigated in the sediment of two estuaries; Araguari to the North (1 15S - 50 30W) and Caete to the South (0 50S - 46 30W). For both estuaries forams and thecamoebians species distribution are atypical relative to other world regions. In both, there are only few calcareous forams and almost all are small and possible of being transported in suspension. Typical estuarine species were not identified. The typical mangrove forams which are agglutinated species were dominant in both estuaries. However, the Caete estuary has a large number of forams species (29), indicating better efficiency in mixing fresh and salt water in comparison to the Araguari. On the other hand, the Araguari has big richness of thecamoebians species (15) indicating fresh water prevalence. The fresh water predominance is due to the Amazon water plume being diverted to the Amapa coast where the Araguari estuary is located. The foraminifera species was also used to determine the salt water penetration in the estuary. In the Caete estuary, salt water penetrates to about 40 km while in the Araguari it does coincide with the limit of the bore tide wave "pororoca" penetration, 45 km. Based on the species succession (forams to thecamoebians species) the Araguary estuary can be divided into three regions controlled by turbidity: the outer, middle and inner estuary. The Caete species succession is not that clear and only could be divided based on salinity into outer and inner estuary. In both estuaries forams and

  17. How can climate change and engineered water conveyance affect sediment dynamics in the San Francisco Bay-Delta system?

    Science.gov (United States)

    Achete, Fernanda; Van der Wegen, Mick; Roelvink, Jan Adriaan; Jaffe, Bruce E.

    2017-01-01

    Suspended sediment concentration is an important estuarine health indicator. Estuarine ecosystems rely on the maintenance of habitat conditions, which are changing due to direct human impact and climate change. This study aims to evaluate the impact of climate change relative to engineering measures on estuarine fine sediment dynamics and sediment budgets. We use the highly engineered San Francisco Bay-Delta system as a case study. We apply a process-based modeling approach (Delft3D-FM) to assess the changes in hydrodynamics and sediment dynamics resulting from climate change and engineering scenarios. The scenarios consider a direct human impact (shift in water pumping location), climate change (sea level rise and suspended sediment concentration decrease), and abrupt disasters (island flooding, possibly as the results of an earthquake). Levee failure has the largest impact on the hydrodynamics of the system. Reduction in sediment input from the watershed has the greatest impact on turbidity levels, which are key to primary production and define habitat conditions for endemic species. Sea level rise leads to more sediment suspension and a net sediment export if little room for accommodation is left in the system due to continuous engineering works. Mitigation measures like levee reinforcement are effective for addressing direct human impacts, but less effective for a persistent, widespread, and increasing threat like sea level rise. Progressive adaptive mitigation measures to the changes in sediment and flow dynamics resulting from sea level rise may be a more effective strategy. Our approach shows that a validated process-based model is a useful tool to address long-term (decades to centuries) changes in sediment dynamics in highly engineered estuarine systems. In addition, our modeling approach provides a useful basis for long-term, process-based studies addressing ecosystem dynamics and health.

  18. Predicting estuarine benthic production using functional diversity

    Directory of Open Access Journals (Sweden)

    Marina Dolbeth

    2014-05-01

    Full Text Available We considered an estuarine system having naturally low levels of diversity, but attaining considerable high production levels, and being subjected to different sorts of anthropogenic impacts and climate events to investigate the relationship between diversity and secondary production. Functional diversity measures were used to predict benthic production, which is considered as a proxy of the ecosystem provisioning services. To this end, we used a 14-year dataset on benthic invertebrate community production from a seagrass and a sandflat habitat and we adopted a sequential modeling approach, where abiotic, trait community weighted means (CWM and functional diversity indices were tested by generalized linear models (GLM, and their significant variables were then combined to produce a final model. Almost 90% of variance of the benthic production could be predicted by combining the number of locomotion types, the absolute maximum atmospheric temperature (proxy of the heat waves occurrence, the type of habitat and the mean body mass, by order of importance. This result is in agreement with the mass ratio hypothesis, where ecosystem functions/services can be chiefly predicted by the dominant trait in the community, here measured as CWM. The increase of benthic production with the number of locomotion types may be seen as greater possibility of using the resources available in the system. Such greater efficiency would increase production. The other variables were also discussed in line of the previous hypothesis and taking into account the general positive relationship obtained between production and functional diversity indices. Overall, it was concluded that traits representative of wider possibilities of using available resources and higher functional diversity are related with higher benthic production.

  19. Building a new regulatory paradigm for coastal and estuarine acidification

    Science.gov (United States)

    Brodeur, J.; Cai, W. J.

    2016-12-01

    Ocean acidification regulation generally falls under the authority of the Clean Water Act (CWA, P.L. 92-500). The CWA has been a powerful tool to improve the country's water quality, but it is most adept at addressing point-source pollutants and contaminants. It requires policymakers to determine "natural levels" of the target pollutant and to attribute changes in water quality to a specific source, both of which are tough or impossible tests for the diffuse carbon imbalance that is associated with ocean acidification, even if we could easily identify the threshold level for harm to organisms (Boehm, 2015). Even where regulators have tried to apply CWA to address acidification, they have been confronted by a lack of baseline data, an inability to specifically identify sources within their jurisdiction, and the fact that existing water quality standards do not capture the impairments that are associated with ocean acidification (Cooley, 2015). In fact, there was a lawsuit brought by the Center for Biological Diversity against the U.S. Environmental Protection Agency (EPA) alleging the agency had failure to regulate this issue. In the end, the courts sided with the EPA, and it continues to struggle with how to use pH and/or saturation state to define a point at which a water body becomes impaired and a threat to sea-life and natural resources. We present an analysis of the complexities related to regulating ocean acidification, the history of work in this area, and suggest a solution that can be tailored to fit unique coastal and estuarine characteristics.

  20. A combined chemical and biological assessment of industrial contamination in an estuarine system in Kerala, India.

    Science.gov (United States)

    Dsikowitzky, Larissa; Nordhaus, Inga; Sujatha, C H; Akhil, P S; Soman, Kunjupilai; Schwarzbauer, Jan

    2014-07-01

    The Cochin Backwaters in India are part of the Vembanad-Kol system, which is a protected wetland and one of the largest estuarine ecosystems in South Asia. The backwaters are a major supplier of fisheries resources and are developed as tourist destination. Periyar River discharges into the northern arm of the system and receives effluents from chemical, petrochemical and metal processing industries which release huge amounts of wastewaters after little treatment. We investigated water and sediment contamination in the industrial vicinity and at one station further away including organic and inorganic contaminants. In total 83 organic contaminants were found, e.g. well known priority pollutants such as endosulfan, hexachlorobenzene, DDT, hexachlorocyclohexane and their metabolites, which likely stem from the industrial manufacturing of organochlorine pesticides. Furthermore, several benzothiazole, dibenzylamine and dicyclohexylamine derivatives were detected, which indicated inputs from rubber producing facilities. Several of these compounds have not been reported as environmental contaminants so far. A comparison of organic contaminant and trace hazardous element concentrations in sediments with reported sediment quality guidelines revealed that adverse effects on benthic species are likely at all stations. The chemical assessment was combined with an investigation of macrobenthic diversity and community composition. Benthic organisms were completely lacking at the site with the highest trace hazardous element concentrations. Highest species numbers, diversity indices and abundances were recorded at the station with the greatest distance to the industrial area. Filter feeders were nearly completely lacking, probably leading to an impairment of the filter function in this area. This study shows that a combination of chemical and biological methods is an innovative approach to achieve a comprehensive characterization of industrial contamination, to evaluate

  1. Toxic pressure of herbicides on microalgae in Dutch estuarine and coastal waters

    Science.gov (United States)

    Booij, Petra; Sjollema, Sascha B.; van der Geest, Harm G.; Leonards, Pim E. G.; Lamoree, Marja H.; de Voogt, W. Pim; Admiraal, Wim; Laane, Remi W. P. M.; Vethaak, A. Dick

    2015-08-01

    For several decades now, there has been an increase in the sources and types of chemicals in estuarine and coastal waters as a consequence of anthropogenic activities. This has led to considerable concern about the effects of these chemicals on the marine food chain. The fact is that estuarine and coastal waters are the most productive ecosystems with high primary production by microalgae. The toxic pressure of specific phytotoxic chemicals now poses a major threat to these ecosystems. In a previous study, six herbicides (atrazine, diuron, irgarol, isoproturon, terbutryn and terbutylazine) were identified as the main contaminants affecting photosynthesis in marine microalgae. The purpose of this study is to investigate the toxic pressure of these herbicides in the Dutch estuarine and coastal waters in relation to the effective photosystem II efficiency (ΦPSII) in microalgae. Temporal and spatial variations in the concentrations of these herbicides were analyzed based on monitoring data. Additionally, a field study was carried out in which chemical analysis of water was performed and also a toxicity assessment using the Pulse Amplitude Modulation (PAM) fluorometry assay that measures ΦPSII. The toxic pressure on ΦPSII in microalgae has decreased with 55-82% from 2003 to 2012, with the Western Scheldt estuary showing the highest toxic pressure. By combining toxicity data from the PAM assay with chemical analysis of herbicide concentrations, we have identified diuron and terbutylazine as the main contributors to the toxic pressure on microalgae. Although direct effects are not expected, the toxic pressure is close to the 10% effect level in the PAM assay. A compliance check with the current environmental legislation of the European Union revealed that the quality standards are not sufficient to protect marine microalgae.

  2. Sediment Transport

    DEFF Research Database (Denmark)

    Liu, Zhou

    Flow and sediment transport are important in relation to several engineering topics, e.g. erosion around structures, backfilling of dredged channels and nearshore morphological change. The purpose of the present book is to describe both the basic hydrodynamics and the basic sediment transport...... mechanics. Chapter 1 deals with fundamentals in fluid mechanics with emphasis on bed shear stress by currents, while chapter 3 discusses wave boundary layer theory. They are both written with a view to sediment transport. Sediment transport in rivers, cross-shore and longshore are dealt with in chapters 2......, 4 and 5, respectively. It is not the intention of the book to give a broad review of the literature on this very wide topic. The book tries to pick up information which is of engineering importance. An obstacle to the study of sedimentation is the scale effect in model tests. Whenever small...

  3. Ma'adim Vallis Estuarine Delta in Elysium Basin and Its Relevance as a Landing Site for Exobiology Exploration on Mars

    Science.gov (United States)

    Grin, E. A.; Cabrol, N. A.

    1998-01-01

    The debouche of Ma'adim Vallis in the Elysium Basin generated a transitional transported sediment structure, which planimetric shape is controlled by the enclosing topography of a deep reentrant gulf of the Basin into the highland. We defined it as an estuarine delta. The location and the importance of this estuarine delta is supported by the theoretical model of graded profile constructed for Ma'adim Vallis, and by two approaches: (i) the reconstruction of Ma'adim Vallis downstream course from Gusev to Elysium Basin, and (ii) the survey of the sediment deposit in the alleged estuary. The longitudinal graded profile of Ma'adim Vallis finds its base-level in the Elysium Basin, at a about 1000 m elevation, which is in agreement with the observed Basin shoreline. This model is supported by observational evidence of flow between the northern rim of Gusev crater, and the Elysium Basin shoreline. This downstream course of Ma'adim Vallis can be divided into three hydrogeologic regions. into three hydrogeologic regions. (a) The first region is a flooded plain (Zephiria Mensae), consisting in chaotic terrain formed by highland rocks, and disintegrated lava of the western flank of Apollinaris. Morphologic indicators of the flood process are: (1) the sediment deposit over the Gusev crater northern rim that reflects the overspilling of the crater-lake water through a 40-km wide gap provided by an ancient impact crater, (2) the tear-drop shaped feature on the northeastern flank of Apollinaris Patera, and (3) the chaotic terrain that suggest the emergence of ground water generated by the seepage of the crater lake through high-permeable broken rampart material. This underground water circulation sustained by the hydrostatic pressure of the crater-lake has likely generated a hydrothermal system in the volcanic environment of Apollinaris Patera. The stratigraphy of the flooded area is identified as Hesperian age, with occurrences of Noachian hilly individual features, and as

  4. Contribution of Spartina maritima to the reduction of eutrophication in estuarine systems

    International Nuclear Information System (INIS)

    Sousa, Ana I.; Lillebo, Ana I.; Cacador, Isabel; Pardal, Miguel A.

    2008-01-01

    Salt marshes are among the most productive ecosystems in the world, performing important ecosystem functions, particularly nutrient recycling. In this study, a comparison is made between Mondego and Tagus estuaries in relation to the role of Spartina maritima in nitrogen retention capacity and cycling. Two mono-specific S. maritima stands per estuary were studied during 1 yr (biomass, nitrogen (N) pools, litter production, decomposition rates). Results showed that the oldest Tagus salt marsh population presented higher annual belowground biomass and N productions, and a slower decomposition rate for litter, contributing to the higher N accumulation in the sediment, whereas S. maritima younger marshes had higher aboveground biomass production. Detritus moved by tides represented a huge amount of aboveground production, probably significant when considering the N balance of these salt marshes. Results reinforce the functions of salt marshes as contributing to a reduction of eutrophication in transitional waters, namely through sedimentation processes. - The crucial capacity of salt marshes to retain nitrogen, thus reducing eutrophication, greatly depends on the salt marsh maturity, rather than the estuarine system

  5. Fatty acids in an estuarine mangrove ecosystem

    Directory of Open Access Journals (Sweden)

    Nabeel M Alikunhi

    2010-06-01

    Full Text Available Los ácidos grasos se han utilizado con éxito para estudiar la transferencia de materia orgánica en las redes alimentarias costeras y estuarinas. Para delinear las interacciones tróficas en las redes, se analizaron perfiles de ácidos grasos en las especies de microbios (Azotobacter vinelandii y Lactobacillus xylosus, camarones (Metapenaeus monoceros y Macrobrachium rosenbergii y peces (Mugil cephalus, que están asociadas con la descomposición de las hojas de dos especies de mangle, Rhizophora apiculata y Avicennia marina. Los ácidos grasos, con excepción de los de cadena larga, exhiben cambios durante la descomposición de las hojas de mangle, con una reducción de los ácidos grasos saturados y un aumento de los monoinsaturados. Los ácidos grasos ramificados están ausentes en las hojas de mangle sin descomponer, pero presentes de manera significativa en las hojas descompuestas, en camarones y peces, representando una fuente importante para ellos. Esto revela que los microbios son productores dominantes que contribuyen significativamente con los peces y camarones en el ecosistema de manglar. Este trabajo demuestra que los marcadores biológicos de los ácidos grasos son una herramienta eficaz para la identificación de las interacciones tróficas entre los productores dominantes y consumidores en este manglar.Fatty acids have been successfully used to trace the transfer of organic matter in coastal and estuarine food webs. To delineate these web connections, fatty acid profiles were analyzed in species of microbes (Azotobacter vinelandii, and Lactobacillus xylosus, prawns (Metapenaeus monoceros and Macrobrachium rosenbergii and finfish (Mugil cephalus, that are associated with decomposing leaves of two mangrove species, Rhizophora apiculata and Avicennia marina. The fatty acids, except long chain fatty acids, exhibit changes during decomposition of mangrove leaves with a reduction of saturated fatty acids and an increase of

  6. Tidal influence on subtropical estuarine methane emissions

    Science.gov (United States)

    Sturm, Katrin; Grinham, Alistair; Werner, Ursula; Yuan, Zhiguo

    2014-05-01

    . Although dissolved methane surface water concentrations were highest in the upper reaches of the estuary, experiencing the lowest tidal currents, fluxes measured using chambers were lower relative to middle and lower reaches. This supports the tidal study findings as higher tidal currents were experienced in the middle and lower reaches. The dominant driver behind estuarine methane water-air fluxes in this system was tidal current speed. Future studies need to take into account flux rates during both transition and slack tide periods to quantify total flux rates.

  7. Aggregation, sedimentation, dissolution and bioavailability of ...

    Science.gov (United States)

    To understand their fate and transport in estuarine systems, the aggregation, sedimentation, and dissolution of CdSe quantum dots (QDs) in seawater were investigated. Hydrodynamic size increased from 40 to 60 nm to >1 mm within 1 h in seawater, and the aggregates were highly polydispersed. Their sedimentation rates in seawater were measured to be 4–10 mm/day. Humic acid (HA), further increased their size and polydispersity, and slowed sedimentation. Light increased their dissolution and release of dissolved Cd. The ZnS shell also slowed release of Cd ions. With sufficient light, HA increased the dissolution of QDs, while with low light, HA alone did not change their dissolution. The benthic zone in estuarine systems is the most probable long-term destination of QDs due to aggregation and sedimentation. The bioavailability of was evaluated using the mysid Americamysis bahia. The 7-day LC50s of particulate and dissolved QDs were 290 and 23 μg (total Cd)/L, respectively. For mysids, the acute toxicity appears to be from Cd ions; however, research on the effects of QDs should be conducted with other organisms where QDs may be lodged in critical tissues such as gills or filtering apparatus and Cd ions may be released and delivered directly to those tissues. Because of their increasing use and value to society, cadmium-based quantum dots (QDs) will inevitably find their way into marine systems. In an effort to understand the fate and transport of CdSe QDs in estuar

  8. Geochemical studies of the river-estuarine systems of Krishna and Godavari

    International Nuclear Information System (INIS)

    Sarin, M.M.; Rao, K.S.; Bhattacharya, S.K.; Ramesh, R.; Somayajulu, B.L.K.

    1985-01-01

    During summer season, the Krishna river waters are enriched in major cations Na, K, Mg, Ca and Si by a factor of 1.2-1.9, in U by a factor of 3 and in delta D by 14.2per cent compared to those of Godavari. The high delta D of Krishna river waters (+ 1.6per cent) over those of Godavari (- 12.6per cent) indicate relatively more evaporation of the former by 15per cent. The uranium concentrations of Krishna waters at Vijayawada is 2.6 μ/l which decreases to 1.6 μ/l at Puligadda which is approx. 100 km downstream, whereas the 234 U/ 238 U activity ratio at both places is identical, 1.65 +- 0.03 suggesting authigenic removal of U in regions downstream of Vijayawada. Also, U does not appear to behave conservatively in the Krishna estuary as has been its behaviour in other Indian and some world rivers; there is removal of U from the Krishna estuarine waters. The major cations and delta D behave conservatively in both Krishna and Godavari estuaries. Si behaves almost conservatively in the Krishna estuary whereas in the Godavari estuary there is about 15per cent Si removal. The fluxes of all the measured constituents from Krishna and Godavari to the Bay of Bengal during the non-monsoon period are calculated. The clay, silt and and sand fractions as well as the Al, Fe, Mn, Cr and Ni concentrations of the clay fractions were determined in eight Krishna estuarine sediments and the results are discussed. The non-monsoonal clay, Al, Fe, Mn, Cr and Ni fluxes from Krishna river to the Bay of Bengal are also estimated. (author)

  9. Biomarker responses and PAH ratios in fish inhabiting an estuarine urban waterway.

    Science.gov (United States)

    Duarte, Rafael Mendonça; Sadauskas-Henrique, Helen; de Almeida-Val, Vera Maria Fonseca; Val, Adalberto Luis; Nice, Helen Elizabeth; Gagnon, Marthe Monique

    2017-10-01

    Many cities worldwide are established adjacent to estuaries and their catchments resulting in estuarine contamination due to intense anthropogenic activities. The aim of this study was to evaluate if fish living in an estuarine urban waterway were affected by contamination, via the measurement of a suite of biomarkers of fish health. Black bream (Acanthopagrus butcheri) were sampled in a small urban embayment and a suite of biomarkers of fish health measured. These were condition factor (CF), liver somatic index (LSI), gonadosomatic index (GSI), hepatic EROD activity, polycyclic aromatic hydrocarbon (PAH) biliary metabolites, serum sorbitol dehydrogenase (s-SDH) and branchial enzymes cytochrome C oxidase (CCO), and lactate dehydrogenase (LDH) activities. The biomarkers of exposure EROD activity, and pyrene- and B(a)P-type biliary metabolites confirmed current or recent exposure of the fish and that fish were metabolizing contaminants. Relative to a reference site, LSI was higher in fish collected in the urban inlet as was the metabolic enzyme LDH activity. CF, GSI, s-SDH, CCO, and naphthalene-type metabolites were at similar levels in the urban inlet relative to the reference site. PAH biliary metabolite ratios of high-molecular-weight to low-molecular-weight suggest that fish from the urban inlet were exposed to pyrogenic PAHs, likely from legacy contamination and road runoff entering the embayment. Similarly, the sediment PAH ratios and the freshness indices suggested legacy contamination of a pyrogenic source, likely originating from the adjacent historic gasworks site and a degree of contamination of petrogenic nature entering the inlet via storm water discharge. Biomarkers of exposure and effect confirmed that black bream collected in the Claisebrook Cove inlet, Western Australia, are currently exposed to contamination and are experiencing metabolic perturbations not observed in fish collected at a nearby reference site. © 2017 Wiley Periodicals, Inc.

  10. White willow sexual regeneration capacity under estuarine conditions in times of climate change

    Science.gov (United States)

    Markus-Michalczyk, Heike; Hanelt, Dieter; Denstorf, Julian; Jensen, Kai

    2016-10-01

    Tidal wetlands provide both habitats for coastal populations and wildlife, and ecosystem services for human welfare. Building with nature regarding cost-effective coastal protection is of increasing interest. Much research has been carried out on plant reproduction capacities in mangroves and salt marshes, but less is known on this issue in tidal freshwater wetlands. Willows are being successfully used for bank stabilization in riverine habitats, however, today white willow softwood forests in tidal wetlands are highly fragmented, and restoration is required e.g. by the European Habitats Directive. Recently, tolerance to increasing salinity and tidal flooding was found for vegetative propagules of floodplain willows. However, the establishment of autochthonous sexual recruits is necessary to conserve the genetic diversity of local populations, and thus may be preferable in restoration. The germination and early seedling establishment of Salix alba (white willow) was experimentally studied under simulated estuarine conditions. The species tolerance to increasing salinity (0, 0.5, 1, 1.5, and 2) was tested in a climate chamber, and its tolerance to flooding at different tidal treatments (control, spring tide, daily tide 15 min and 2 h flooding) in the greenhouse. Germination was neither affected by increasing salinity nor by tidal flooding. Salix seedlings established up to salinity 1.5, but cotyledon performance and radicle growth was largely reduced at salinity 2. Under tidal flooding, seedling growth was similar in all treatments. However, in the treatments with daily tides seedling anchorage in the substrate took more than two weeks, and fewer seedlings reached a suitable length to approach the high water line. We assess S. alba sexual regeneration under estuarine conditions as generally possible. Further studies are needed on the effects of sedimentation-erosion processes on willow establishment in the field, especially on feedbacks between Salix survival and

  11. 76 FR 40338 - National Estuarine Research Reserve System

    Science.gov (United States)

    2011-07-08

    ... coastal issues of the reserve related to water quality (non-point source pollution), invasive species... Reserve System AGENCY: Estuarine Reserves Division, Office of Ocean and Coastal Resource Management.... ACTION: Notice of Approval and Availability for Revised Management Plans for ACE Basin, SC National...

  12. Minimal incorporation of Deepwater Horizon oil by estuarine filter feeders

    International Nuclear Information System (INIS)

    Fry, Brian; Anderson, Laurie C.

    2014-01-01

    Highlights: • Oil from the Deepwater Horizon oil spill entered Louisiana bays in mid-2010. • Oil was used minimally (<1%) in diets of mussels and barnacles. • Also, oil did not enhance planktonic respiration rates. • Use of oil carbon was relatively small in these productive estuarine food webs. - Abstract: Natural abundance carbon isotope analyses are sensitive tracers for fates and use of oil in aquatic environments. Use of oil carbon in estuarine food webs should lead to isotope values approaching those of oil itself, −27‰ for stable carbon isotopes reflecting oil origins and −1000‰ for carbon-14 reflecting oil age. To test for transfer of oil from the 2010 Deepwater Horizon spill into estuarine food webs, filter-feeding barnacles (Balanus sp.) and marsh mussels (Geukensia demissa) were collected from Louisiana estuaries near the site of the oil spill. Carbon-14 analyses of these animals from open waters and oiled marshes showed that oil use was <1% and near detection limits estimated at 0.3% oil incorporation. Respiration studies showed no evidence for enhanced microbial activity in bay waters. Results are consistent with low dietary impacts of oil for filter feeders and little overall impact on respiration in the productive Louisiana estuarine systems

  13. Macrophytes in estuarine gradients : Flow through flexible vegetation

    NARCIS (Netherlands)

    Dijkstra, J.T.

    2012-01-01

    Aquatic plants –or macrophytes- are an important part of coastal, estuarine and freshwater ecosystems worldwide, both from an ecological and an engineering viewpoint. Their meadows provide a wide range of ecosystem services: forming a physical protection of the shoreline, enhancing water quality and

  14. Marine and Estuarine Ecology. Man and the Gulf of Mexico.

    Science.gov (United States)

    Irby, Bobby N.; And Others

    "Man and the Gulf of Mexico (MGM)" is a marine science curriculum developed to meet the marine science needs of tenth through twelfth grade students in Mississippi and Alabama schools. This MGM unit, which focuses on marine and estuarine ecology, is divided into six sections. The first section contains unit objectives, discussions of the…

  15. Does biodiversity of estuarine phytoplankton depend on hydrology?

    NARCIS (Netherlands)

    Ferreira, JG; Wolff, WJ; Simas, TC; Bricker, SB

    2005-01-01

    Phytoplankton growth in estuaries is controlled by factors such as flushing, salinity tolerance, light, nutrients and grazing. Here, we show that biodiversity of estuarine phytoplankton is related to flushing, and illustrate this for some European estuaries. The implications for the definition of

  16. Salt Marsh--Estuarine Ecosystem: A Liquid Asset

    Science.gov (United States)

    Steever, E. Zell

    1977-01-01

    A comprehensive description of the salt marsh-estuarine ecosystem is provided. Topics discussed include: the general geologic history and formation of this ecosystem; physical and chemical parameters; variety; primary productivity; tidal zones; kind, sizes and abundance of vegetation; and the environmental factors influencing vegetation. (BT)

  17. DCERP Defense Coastal/Estuarine Research Program Workshop Proceedings

    Science.gov (United States)

    2005-02-01

    regions (including submerged aquatic vegetation, macroalgae and microalgae) • Estuarine and riverine water column • Beach and dunes • Surf zone...following the activation of the new water treatment plant. Assess upstream and tributary contaminant contributions resulting in eutrophication problems...12 3.2 WATER QUALITY

  18. Estuarine use by spotted grunter Pomadasys commersonnii in a ...

    African Journals Online (AJOL)

    Factors influencing estuarine use and marine excursions by spotted grunter Pomadasys commersonnii in the Great Fish Estuary, South Africa, were studied using manual and automated telemetry methods. In all, 20 individuals, ranging from 362 mm to 698 mm total length (TL), were caught and tagged with acousticcoded ...

  19. 75 FR 65613 - National Estuarine Research Reserve System

    Science.gov (United States)

    2010-10-26

    ... based on priority issues defined by the reserve. The objectives described in this plan are designed to... DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Estuarine Research..., National Ocean Service, National Oceanic and Atmospheric Administration, U.S. Department of Commerce...

  20. Depth profile distribution of Cr, Cu, Co, Ni and Pb in the sediment cores of Mumbai Harbour Bay

    International Nuclear Information System (INIS)

    Madhuparna, D.; Hemalatha, P.; Raj, Sanu S.; Jha, S.K.; Tripathi, R.M.

    2014-01-01

    Estuarine and coastal sediments act as ultimate sink for trace metals that are discharged into the aquatic environment. Sources of environmental contaminants to the coastal system are numerous and may enter the estuarine environment via a number of pathways Mumbai Harbour Bay on the western coast of India, receives low level nuclear wastes and industrial and domestic sewage waste from the surrounding dwellings. Also, the bay is extensively exploited for various other local activities. The present study was carried out in the bay sediment cores to investigate the depth profile distribution of trace element concentration. Biologically significant toxic elements such as Cr, Cu, Co, Ni and Pb were estimated in the sediment cores to find out pattern of distribution in the sediment bed to follow the accumulation of elements with respect to depth

  1. Biogeochemical studies of technetium in marine and estuarine ecosystems. Progress report, 1 July 1979-30 June 1980

    International Nuclear Information System (INIS)

    Beasley, T.M.

    1980-01-01

    Progress is reported in research dealing with the biogeochemical behavior of technetium in marine and estuarine ecosystems. Studies were planned to elaborate the biokinetic behavior of Tc as TcO 4 - in selected marine and estuarine organisms and to determine the affinity of TcO 4 - for different marine sediments under oxygenated conditions. It is concluded that concentration factors for TcO 4 - in bivalve molluscs (oysters and mussels) do not exceed 2 when calculated for whole animals and when uptake is directly from water. Direct uptake from water by limpets (archeogastropod) are very much lower than have been reported for red abalone (archeogastropod). Whole body concentration factors for TcO 4 - in the plaice, Pleuronectes platessa, where uptake is directly from labeled seawater, do not exceed 10 at equilibrium. Both the lobster, Homarus gammaris and the polychaete, Nereis diversicolor appear to concentrate Tc efficiently from water labelled intially with TcO 4 - . Both plaice and rays (Raja clavata) fed /sup 95m/Tc labeled Nereis show an initial rapid loss of the isotope for approximately five days. Thereafter, loss is much reduced. Shrimp (Palaemon elegans), Cragnon sp.) and Crab (Cancer pagurus) show concentration factors similar to plaice (C.F. is less than 10). Isopods, however, have concentration factors of only 3 following four weeks exposure to labeled seawater. Uptake of TcO 4 - by phytoplankton is extremely low, which precludes experiments in which TcO 4 - labeled phytoplankton can be fed to either bivalve molluscs or microzooplankton. Sediment distribution coefficients for TcO 4 - are essentially zero and are independent of sediment type in well oxygenated seawater. Experiments to date have shown that it is not possible to make generalizations concerning the bioavailability of TcO 4 - to marine organisms

  2. Literature Review of Unconsolidated Sediment in San Francisco Bay and Nearby Pacific Ocean Coast

    Directory of Open Access Journals (Sweden)

    Barry R. Keller

    2009-09-01

    Full Text Available A review of the geologic literature regarding sedimentation in the San Francisco Bay estuarine system shows that the main part of the bay occupies a structural tectonic depression that developed in Pleistocene time. Eastern parts, including San Pablo Bay and Suisun Bay, have had sedimentation throughout late Mesozoic and Tertiary. Carquinez Strait and the Golden Gate may represent antecedent stream erosion. Sedimentation has included estuarine, alluvial, and eolian deposition. The ages of estuarine deposition includes the modern high sea level stand and earlier Pleistocene interglacial periods. Sediment sources can be generally divided into the Coast Ranges, particularly the Franciscan Complex, and “Sierran.” Much of the estuarine system is floored by very fine sediment, with local areas of sand floor. Near the Golden Gate, sediment size decreases in both directions away from the deep channel. Bedforms include sand waves (submarine dunes, flat beds, and rock and boulders. These are interpreted in terms of dominant transport directions. Near the Golden Gate is an ebb-tidal delta on the outside (including San Francisco bar and a flood-tidal delta on the inside (parts of Central Bay. The large tidal prism causes strong tidal currents, which in the upper part of the estuary are normally much stronger than river currents, except during large floods. Cultural influences have altered conditions, including hydraulic mining debris, blasting of rocks, dredging of navigation channels, filling of the bay, and commercial sand mining. Many of these have served to decrease the tidal prism, correspondingly decreasing the strength of tidal currents.

  3. Transverse structure of tidal flow, residual flow and sediment concentration in estuaries: sensitivity to tidal forcing and water depth

    NARCIS (Netherlands)

    Huijts, K.M.H.|info:eu-repo/dai/nl/304831867; de Swart, H.E.|info:eu-repo/dai/nl/073449725; Schramkowski, G.P.; Schuttelaars, H.M.

    2011-01-01

    An analytical and a numerical model are used to understand the response of velocity and sediment distributions over Gaussian-shaped estuarine cross-sections to changes in tidal forcing and water depth. The estuaries considered here are characterized by strong mixing and a relatively weak

  4. Beryllium-10 in Chesapeake Bay sediments: an indicator of sediment provenance

    International Nuclear Information System (INIS)

    Helz, G.R.; Valette-Silver, Nathalie

    1992-01-01

    In a plot of 10 Be vs. Fe, central Chesapeake Bay sediments can be segregated into distinct units. This plot reveals an unexpected, statistically significant difference between sediments on the eastern and western flanks of the main channel, implying different origins. Although the 10 Be concentrations in sediments from these two regions span as much as an order of magnitude range, the 10 Be/Fe ratios vary by an amount approximating analytical error alone. The large concentration ranges are ascribed to hydraulic sorting, which can produce variance in composition while not affecting ratios between grain surface components such as Fe and Be. On the basis of 10 Be/Fe signatures, sediments on the western flank of the main channel appear to have been derived from the Susquehanna or another Piedmont/Appalachian river. Sediments on the eastern flank may have been transported from the south, by landward flowing bottom currents, or may be relics of a Pleistocene estuarine system. Conditions under which 10 Be may prove a useful tool in sediment provenance studies elsewhere are discussed. (Author)

  5. Investigations into the differential reactivity of endogenous and exogenous mercury species in coastal sediments.

    Science.gov (United States)

    Bouchet, S; Rodriguez-Gonzalez, P; Bridou, R; Monperrus, M; Tessier, E; Anschutz, P; Guyoneaud, R; Amouroux, D

    2013-03-01

    Stable isotopic tracer methodologies now allow the evaluation of the reactivity of the endogenous (ambient) and exogenous (added) Hg to further predict the potential effect of Hg inputs in ecosystems. The differential reactivity of endogenous and exogenous Hg was compared in superficial sediments collected in a coastal lagoon (Arcachon Bay) and in an estuary (Adour River) from the Bay of Biscay (SW France). All Hg species (gaseous, aqueous, and solid fraction) and ancillary data were measured during time course slurry experiments under variable redox conditions. The average endogenous methylation yield was higher in the estuarine (1.2 %) than in the lagoonal sediment (0.5 %), although both methylation and demethylation rates were higher in the lagoonal sediment in relation with a higher sulfate-reducing activity. Demethylation was overall more consistent than methylation in both sediments. The endogenous and exogenous Hg behaviors were always correlated but the exogenous inorganic Hg (IHg) partitioning into water was 2.0-4.3 times higher than the endogenous one. Its methylation was just slightly higher (1.4) in the estuarine sediment while the difference in the lagoonal sediment was much larger (3.6). The relative endogenous and exogenous methylation yields were not correlated to IHg partitioning, demonstrating that the bioavailable species distributions were different for the two IHg pools. In both sediments, the exogenous IHg partitioning equaled the endogenous one within a week, while its higher methylation lasted for months. Such results provide an original assessment approach to compare coastal sediment response to Hg inputs.

  6. Pollution biomarkers in estuarine animals: critical review and new perspectives.

    Science.gov (United States)

    Monserrat, José M; Martínez, Pablo E; Geracitano, Laura A; Amado, Lílian Lund; Martins, Camila Martinez Gaspar; Pinho, Grasiela Lopes Leães; Chaves, Isabel Soares; Ferreira-Cravo, Marlize; Ventura-Lima, Juliane; Bianchini, Adalto

    2007-01-01

    In this review, recent developments in monitoring toxicological responses in estuarine animals are analyzed, considering the biomarker responses to different classes of pollutants. The estuarine environment imposes stressful conditions to the organisms that inhabit it, and this situation can alter their sensitivity to many pollutants. The specificity of some biomarkers like metallothionein tissue concentration is discussed in virtue of its dependence on salinity, which is highly variable in estuaries. Examples of cholinesterase activity measurements are also provided and criteria to select sensitive enzymes to detect pesticides and toxins are discussed. Regarding non-specific biomarkers, toxic responses in terms of antioxidant defenses and/or oxidative damage are also considered in this review, focusing on invertebrate species. In addition, the presence of an antioxidant gradient along the body of the estuarine polychaete Laeonereis acuta (Nereididae) and its relationship to different strategies, which deal with the generation of oxidative stress, is reviewed. Also, unusual antioxidant defenses against environmental pro-oxidants are discussed, including the mucus secreted by L. acuta. Disruption of osmoregulation by pollutants is of paramount importance in several estuarine species. In some cases such as in the estuarine crab Chasmagnathus granulatus, there is a trade off between bioavailability of toxicants (e.g. metals) and their interaction with key enzymes such as Na(+)-K(+)-ATPase and carbonic anhydrase. Thus, the metal effect on osmoregulation is also discussed in the present review. Finally, field case studies with fish species like the croaker Micropogonias furnieri (Scianidae) are used to illustrate the application of DNA damage and immunosuppressive responses as potential biomarkers of complex mixture of pollutants.

  7. The use of acoustic doppler meters to estimate sediment and nutrient concentrations in freshwater inflows to Texas coastal ecosystems

    Science.gov (United States)

    Zullmar Lucena; Micheal Lee

    2016-01-01

    Excessive sediment and nutrient loading are among the leading causes of impairment in water bodies of the United States due to their effect on biologic productivity, water quality, and aquatic food webs. Understanding the nutrient and suspended sediment loads affecting estuarine waters is fundamental to the assessment of the physical, chemical, and biological processes...

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

    Digital Repository Service at National Institute of Oceanography (India)

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

    ., Jadhav, S., Harji, R., Sawant, S., Venket, K., Anil, A. C., 2004. Butyltins in water, biofilm and sediments of the west coast of India. Chemosphere 57, 897-907. Burton, E. D., Phillips, I. R., Hawker, D. W., 2004. Sorption and desorption behaviour... of tributyltin with natural sediments. Environmental Science & Technology 38, 6694 – 6700. Burton, E. D., Phillips, I. R., Hawker, D. W., 2005. In-situ partitioning of butyltin species in estuarine sediments. Chemosphere 59, 585 – 592. Burton, E. D., Phillips...

  9. A Manual to Identify Sources of Fluvial Sediment

    Science.gov (United States)

    Sedimentation is one of the main causes of stream/river aquatic life use impairments in R3. Currently states lack standard guidance on appropriate tools available to quantify sediment sources and develop sediment budgets in TMDL Development. Methods for distinguishing sediment t...

  10. The relationship between sediment and plutonium budgets in a small macrotidal estuary: Esk Estuary, Cumbria, UK

    International Nuclear Information System (INIS)

    Kelly, M.; Emptage, M.; Mudge, S.; Bradshaw, K.; Hamilton-Taylor, J.

    1991-01-01

    During a spring tide, measurements were made of sediment and 239,240 Pu discharges through a cross-section of the Esk estuary. These indicated that over the full tidal cycle, the inner estuary had a net gain of ca. 18 t of sediment and ca. 85 MBq of particulate phase 239,240 Pu, and a probable net loss of ca. 1 to 2 MBq of solution phase 239,240 Pu. Each of these was the net result of large gross discharges of sediment and plutonium into and out of the estuary for which the sea was the main source, with eroded estuarine sediment providing an additional minor source of sediment, of particulate phase plutonium and, via desorption, of solution phase plutonium. A net input with each tide, of sediment and its associated radionuclides, is considered to be typical for the Esk estuary under the normal conditions of low river flows. (author)

  11. Distribution of branched GDGTs in surface sediments from the Colville River, Alaska: Implications for the MBT'/CBT paleothermometer in Arctic marine sediments

    Science.gov (United States)

    Hanna, Andrea J. M.; Shanahan, Timothy M.; Allison, Mead A.

    2016-07-01

    Significant climate fluctuations in the Arctic over the recent past, and additional predicted future temperature changes, highlight the need for high-resolution Arctic paleoclimate records. Arctic coastal environments supplied with terrigenous sediment from Arctic rivers have the potential to provide annual to subdecadal resolution records of climate variability over the last few millennia. A potential tool for paleotemperature reconstructions in these marine sediments is the revised methylation index of branched tetraethers (MBT')/cyclization ratio of branched tetraethers (CBT) proxy based on branched glycerol dialkyl glycerol tetraethers (brGDGTs). In this study, we examine the source of brGDGTs in the Colville River, Alaska, and the adjacent Simpson Lagoon and reconstruct temperatures from Simpson Lagoon sediments to evaluate the applicability of this proxy in Arctic estuarine environments. The Colville catchment soils, fluvial sediments, and estuarine sediments contain statistically similar brGDGT distributions, indicating that the brGDGTs throughout the system are soil derived with little alteration from in situ brGDGT production in the river or coastal waters. Temperatures reconstructed from the MBT'/CBT indices for surface samples show good agreement with regional summer (June through September) temperatures, suggesting a seasonal bias in Arctic temperature reconstructions from the Colville system. In addition, we reconstruct paleotemperatures from an estuarine sediment core that spans the last 75 years, revealing an overall warming trend in the twentieth century that is consistent with trends observed in regional instrumental records. These results support the application of this brGDGT-based paleotemperature proxy for subdecadal-scale summer temperature reconstructions in Arctic estuaries containing organic material derived from sediment-laden, episodic rivers.

  12. Preservation of a Late Glacial terrestrial and Holocene estuarine record on the margins of Kaipara Harbour, Northland, New Zealand

    International Nuclear Information System (INIS)

    Nichol, S.; Deng, Y.; Horrocks, M.; Zhou, W.; Hume, T.

    2009-01-01

    Subtidal to intertidal deposits from the margins of Kaipara Harbour in Northland preserve a c. 23,000 year incomplete sedimentary record of the transition from terrestrial to estuarine conditions. Cores are used to reconstruct the depositional setting for this transition, interpreted as a succession from dune and freshwater wetland to shallow estuarine environments. The fossil pollen record provides a proxy of Last Glacial Maximum and Late Glacial vegetation for the area. Stability of the Pleistocene dune landscape during the postglacial marine transgression is interpreted on the basis of strong dominance of tall forest taxa (Dacrydium) in the pollen record and soil development in dune sands, with preservation aided by location along the estuary margin. During the Holocene, reworking of the buried dune and wetland sediments has only reached to a depth of 1.5 m below the modern tidal flat. As such, the site provides a rare example of good preservation of Pleistocene deposits at the coast, where extensive reworking and loss of record are more typical. (author). 41 refs., 6 figs., 1 tab

  13. Drivers of change in estuarine-coastal ecosystems: Discoveries from four decades of study in San Francisco Bay

    Science.gov (United States)

    Cloern, J.E.; Jassby, A.D.

    2012-01-01

    Poised at the interface of rivers, ocean, atmosphere and dense human settlement, estuaries are driven by a large array of natural and anthropogenic forces. San Francisco Bay exemplifies the fast-paced change occurring in many of the world's estuaries, bays and inland seas in response to these diverse forces. We use observations from this particularly well-studied estuary to illustrate responses to six drivers that are common agents of change where land and sea meet: water consumption and diversion; human modification of sediment supply; introduction of non-native species; sewage input; environmental policy; and climate shifts. In San Francisco Bay, responses to these drivers include, respectively, shifts in the timing and extent of freshwater inflow and salinity intrusion; decreasing turbidity; restructuring of plankton communities; nutrient enrichment; elimination of hypoxia and reduced metal contamination of biota; and food web changes that decrease resistance of the estuary to nutrient pollution. Detection of these changes and discovery of their causes through environmental monitoring have been essential for establishing and measuring outcomes of environmental policies that aim to maintain high water quality and sustain services provided by estuarine-coastal ecosystems. The wide range of variability time scales and the multiplicity of interacting drivers place heavy demands on estuarine monitoring programs. But the San Francisco Bay case study illustrates why the imperative for monitoring has never been greater.

  14. Drivers of change in estuarine-coastal ecosystems: Discoveries from four decades of study in San Francisco Bay

    Science.gov (United States)

    Cloern, James E.; Jassby, Alan D.

    2012-12-01

    Poised at the interface of rivers, ocean, atmosphere and dense human settlement, estuaries are driven by a large array of natural and anthropogenic forces. San Francisco Bay exemplifies the fast-paced change occurring in many of the world's estuaries, bays, and inland seas in response to these diverse forces. We use observations from this particularly well-studied estuary to illustrate responses to six drivers that are common agents of change where land and sea meet: water consumption and diversion, human modification of sediment supply, introduction of nonnative species, sewage input, environmental policy, and climate shifts. In San Francisco Bay, responses to these drivers include, respectively, shifts in the timing and extent of freshwater inflow and salinity intrusion, decreasing turbidity, restructuring of plankton communities, nutrient enrichment, elimination of hypoxia and reduced metal contamination of biota, and food web changes that decrease resistance of the estuary to nutrient pollution. Detection of these changes and discovery of their causes through environmental monitoring have been essential for establishing and measuring outcomes of environmental policies that aim to maintain high water quality and sustain services provided by estuarine-coastal ecosystems. The many time scales of variability and the multiplicity of interacting drivers place heavy demands on estuarine monitoring programs, but the San Francisco Bay case study illustrates why the imperative for monitoring has never been greater.

  15. Estuarine development and early Holocene transgression across an aeolianite substrate, Caesarea, central Israel

    Science.gov (United States)

    Goff, John A.; Austin, James A.; Goodman-Tchernov, Beverly N.

    2018-04-01

    Estuaries are important features on the coastal landscape due to their potential for rich, diverse, and abundant resources. The modern coast of the southeast Mediterranean is largely devoid of estuaries except in rare circumstances where ample sands are delivered to the shore, such as east of the Nile Delta. Whether or not today's condition is reflective of that present during lower sea-levels is greatly speculative in part due to a dearth of high-resolution sub-surface mapping in the shallower (sediments in water depths 45-10 mbsl, both within paleo-channels of the Crocodile and Hadera rivers, and more broadly across the shelf. These water depths correspond to early Holocene dates ( 10.5-7.5 ka) which, based on global sea-level curves, was a period of rapid ( 1-1.7 cm/yr) sea-level rise. Now-submerged aeolianite ridges (locally referred to as 'kurkar'), cemented aeolian deposits formed during pre-Last-Glacial-Maximum (LGM) seaward advance (regression) of the coastline, likely provided some offshore barrier for estuarine development. These were insufficient, however, to account for all the estuarine deposition interpreted, leading us to hypothesize that sand-constructed barrier islands were also present as sea-level rose during the Holocene. This supply of sand, clearly greater than what is evident today, could have originated from sea-level rise phase eroding Nile Delta sediments transported northward by littoral currents, or from increased output from local rivers during wetter climatic conditions. We also observe a transition from linear, shore-parallel aeolianite ridge morphology features on land and in shallow water, to nested, arcuate features below 30 mbsl. Whereas the linear ridges are thought to be coastal foredune remnants abandoned by the retreating shoreline, the arcuate forms resemble fossil parabolic (blowout) dunes. Based on the recent initiation of parabolic dunes on Cape Cod following anthropogenic denudation of forests there, we suggest that

  16. Reductive dehalogenation activity of indigenous microorganism in sediments of the Hackensack River, New Jersey.

    Science.gov (United States)

    Sohn, Seo Yean; Häggblom, Max M

    2016-07-01

    Organohalogen pollutants are of concern in many river and estuarine environments, such as the New York-New Jersey Harbor estuary and its tributaries. The Hackensack River is contaminated with various metals, hydrocarbons and halogenated organics, including polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins. In order to examine the potential for microbial reductive dechlorination by indigenous microorganisms, sediment samples were collected from five different estuarine locations along the Hackensack River. Hexachlorobenzene (HCB), hexabromobenzene (HBB), and pentachloroaniline (PCA) were selected as model organohalogen pollutants to assess anaerobic dehalogenating potential. Dechlorinating activity of HCB and PCA was observed in sediment microcosms for all sampling sites. HCB was dechlorinated via pentachlorobenzene (PeCB) and trichlorobenzene (TriCB) to dichlorobenzene (DCB). PCA was dechlorinated via tetrachloroaniline (TeCA), trichloroanilines (TriCA), and dichloroanilines (DCA) to monochloroaniline (MCA). No HBB debromination was observed over 12 months of incubation. However, with HCB as a co-substrate slow HBB debromination was observed with production of tetrabromobenzene (TeBB) and tribromobenzene (TriBB). Chloroflexi specific 16S rRNA gene PCR-DGGE followed by sequence analysis detected Dehalococcoides species in sediments of the freshwater location, but not in the estuarine site. Analysis targeting 12 putative reductive dehalogenase (rdh) genes showed that these were enriched concomitant with HCB or PCA dechlorination in freshwater sediment microcosms. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Evolution of sediment plumes in the Chesapeake bay and implications of climate variability.

    Science.gov (United States)

    Zheng, Guangming; DiGiacomo, Paul M; Kaushal, Sujay S; Yuen-Murphy, Marilyn A; Duan, Shuiwang

    2015-06-02

    Fluvial sediment transport impacts fisheries, marine ecosystems, and human health. In the upper Chesapeake Bay, river-induced sediment plumes are generally known as either a monotonic spatial shape or a turbidity maximum. Little is known about plume evolution in response to variation in streamflow and extreme discharge of sediment. Here we propose a typology of sediment plumes in the upper Chesapeake Bay using a 17 year time series of satellite-derived suspended sediment concentration. On the basis of estimated fluvial and wind contributions, we define an intermittent/wind-dominated type and a continuous type, the latter of which is further divided into four subtypes based on spatial features of plumes, which we refer to as Injection, Transport, Temporary Turbidity-Maximum, and Persistent Turbidity-Maximum. The four continuous types exhibit a consistent sequence of evolution within 1 week to 1 month following flood events. We also identify a "shift" in typology with increased frequency of Turbidity-Maximum types before and after Hurricane Ivan (2004), which implies that extreme events have longer-lasting effects upon estuarine suspended sediment than previously considered. These results can serve as a diagnostic tool to better predict distribution and impacts of estuarine suspended sediment in response to changes in climate and land use.

  18. Bioaccumulation of sediment-associated fluoranthene in benthic copepods: uptake, elimination and biotransformation

    International Nuclear Information System (INIS)

    Lotufo, G.R.

    1998-01-01

    Most polycyclic aromatic hydrocarbons (PAHs) entering aquatic systems reside in sediments and in the storage lipids of the benthic biota. Massive amounts of PAHs reach estuarine systems and threaten their ecosystems. Copepods abound in the estuarine benthos, where they are an important component of food webs. The accumulation of sediment-associated [ 14 C]fluoranthene was examined in adult females of two species of sediment-dwelling copepods, Schizopera knabeni and Coullana sp., collected from a Louisiana salt marsh. Accumulation was measured throughout a short- (24 h) and a long-term (10-day) exposure to concentrations in the sediment ranging from 0 to 1652 nmol (g dry wt.) -1 . Fluoranthene apparent steady state body residue was reached very rapidly ( 14 C activity in the tissues following a 96-h sediment exposure in both species. Given that fluoranthene was taken up from spiked sediment very efficiently and reached steady-state levels in the tissues very rapidly, PAH-contaminated sediments may pose a risk for benthic copepods and their predators. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  19. Paleomagnetic investigation of late Quaternary sediments of south San Francisco Bay, California

    Science.gov (United States)

    Hillhouse, John W.

    1977-01-01

    Paleomagnetic inclinations of the Late Quaternary sediments of South San Francisco Bay were determined from bore hole samples collected near Dumbarton Bridge. The sediments consist of estuarine muds and nonmarine sand deposits, floored by bedrock of the Mesozoic Franciscan Formation. - Beneath Dumbarton Bridge the entire sedimentary fill is normally polarized; therefore, the fill postdates the Brunhes-Matayama polarity reversal (700,000 y. B.P.). Magnetic time lines such as the Mono Lake excursion (24,000 y. B.P.) and the reversed Blake event (110,000 y B.P.) were not found in this bore hole. In addition to Holocene and modern deposits of San Francisco Bay, an older estuarine unit occurs in the stratigraphic section. The older unit was deposited during a period of high sea level, tentatively correlated with the Sangamon interglacial period. Because evidence of the Blake event is not present in the older estuarine unit, the proposed age of this unit could not be confirmed. Although the Holocene estuarine deposits of South San Francisco Bay carry stable remanent magnetization, a reliable record of geomagnetic secular variation could not be recovered because the water-saturated sdiment was deformed by drilling.

  20. Increased terrestrial to ocean sediment and carbon fluxes in the northern Chesapeake Bay associated with twentieth century land alteration

    Science.gov (United States)

    Saenger, C.; Cronin, T. M.; Willard, D.; Halka, J.; Kerhin, R.

    2008-01-01

    We calculated Chesapeake Bay (CB) sediment and carbon fluxes before and after major anthropogenic land clearance using robust monitoring, modeling and sedimentary data. Four distinct fluxes in the estuarine system were considered including (1) the flux of eroded material from the watershed to streams, (2) the flux of suspended sediment at river fall lines, (3) the burial flux in tributary sediments, and (4) the burial flux in main CB sediments. The sedimentary maximum in Ambrosia (ragweed) pollen marked peak land clearance (~1900 a.d.). Rivers feeding CB had a total organic carbon (TOC)/total suspended solids of 0.24??0.12, and we used this observation to calculate TOC fluxes from sediment fluxes. Sediment and carbon fluxes increased by 138-269% across all four regions after land clearance. Our results demonstrate that sediment delivery to CB is subject to significant lags and that excess post-land clearance sediment loads have not reached the ocean. Post-land clearance increases in erosional flux from watersheds, and burial in estuaries are important processes that must be considered to calculate accurate global sediment and carbon budgets. ?? 2008 Coastal and Estuarine Research Federation.

  1. Alteration in Solid State Phosphorous With Depth in Sediments Along the Salinity Transition Zone of a Major Chesapeake Bay Tributary

    Science.gov (United States)

    Hartzell, J. L.; Jordan, T. E.

    2006-05-01

    Determining the fate of particulate phosphorus in estuaries is essential for addressing the widespread problem of estuarine eutrophication, and is key to understanding P cycling and developing accurate global P budgets. Prominent reservoirs of P in surficial sediments include particulate P associated with iron or organic C. However, the importance of these reservoirs changes with the decomposition of organic matter and the reduction of iron. Also, the importance of iron bound P may decrease with increasing salinity due to the formation of iron sulfides. To investigate estuarine P burial and its relationship to salinity, we collected sediment cores of one-meter depth along the salinity gradient of the Patuxent River estuary (Maryland, USA), a major tributary of Chesapeake Bay. The sediments were analyzed using a sequential sedimentary extraction procedure that quantifies five separate reservoirs of particulate P. Total phosphorus concentrations in freshwater sediments were significantly higher than those in more saline sediments at all depths. Conversely, porewater phosphate concentrations were significantly lower in freshwater sediments than in the more saline sediments. Total P in the saline sediment cores decreased with depth, correlating to a reduction in iron-bound P. However, we did not find a concurrent increase in authigenic apatite with depth. Our findings indicate that mechanisms controlling changes in P sorption to sediments change profoundly with salinity and may contribute to increased bioavailability of phosphates with increasing salinity.

  2. Methodology for impact assessment in the estuarine/marine environment

    International Nuclear Information System (INIS)

    Haven, K.F.

    1975-01-01

    Impacts on the estuarine/marine environment can be assessed in economic terms by tracing the impact flow out of the economic sector through the marine environment and back into the economic sector as changes in natural resource availability. An impact can then be measured by the changes created in the economic sector by changes in resource availability. Primary emphasis is placed on the development of an appropriate ecological model of the estuarine environment for this purpose. Two types, an ecological input/output model and a dynamic (difference equation) model, are proposed. Acceptability criteria for these models include the ability to track lethal and sublethal, direct and indirect (food web), and short- and long-term effects of a variety of pollutants related to the production and use of various energy resources

  3. Marine and estuarine natural microbial biofilms: ecological and biogeochemical dimensions

    Directory of Open Access Journals (Sweden)

    O. Roger Anderson

    2016-08-01

    Full Text Available Marine and estuarine microbial biofilms are ubiquitously distributed worldwide and are increasingly of interest in basic and applied sciences because of their unique structural and functional features that make them remarkably different from the biota in the plankton. This is a review of some current scientific knowledge of naturally occurring microbial marine and estuarine biofilms including prokaryotic and microeukaryotic biota, but excluding research specifically on engineering and applied aspects of biofilms such as biofouling. Because the microbial communities including bacteria and protists are integral to the fundamental ecological and biogeochemical processes that support biofilm communities, particular attention is given to the structural and ecological aspects of microbial biofilm formation, succession, and maturation, as well as the dynamics of the interactions of the microbiota in biofilms. The intent is to highlight current state of scientific knowledge and possible avenues of future productive research, especially focusing on the ecological and biogeochemical dimensions.

  4. Influence of anthropogenic stress on fitness and behaviour of a key-species of estuarine ecosystems, the ragworm Nereis diversicolor

    Energy Technology Data Exchange (ETDEWEB)

    Mouneyrac, C., E-mail: catherine.mouneyrac@uco.f [MMS, EA2160, Faculte de pharmacie, 1 rue G. Veil, BP 53508, 44035 Nantes Cedex 1 (France); Institut de Biologie et Ecologie Appliquee, CEREA, Universite Catholique de l' Ouest, 3 Place Andre Leroy, Angers, 44 rue Rabelais, 49008 Angers Cedex 01 (France); Perrein-Ettajani, H. [MMS, EA2160, Faculte de pharmacie, 1 rue G. Veil, BP 53508, 44035 Nantes Cedex 1 (France); Institut de Biologie et Ecologie Appliquee, CEREA, Universite Catholique de l' Ouest, 3 Place Andre Leroy, Angers, 44 rue Rabelais, 49008 Angers Cedex 01 (France); Amiard-Triquet, C. [CNRS, Universite de Nantes, MMS, EA2160, Faculte de pharmacie, 1 rue G. Veil, BP 53508, 44035 Nantes Cedex 1 (France)

    2010-01-15

    Fitness, (biometric measurements, reproduction) and behaviour that are ecologically relevant biomarkers in assessing the quality of estuarine sediments were studied by comparing the responses of the polychaete worm Nereis diversicolor - a key species in estuaries - along a pollution gradient. Intersite differences were shown for all the measured parameters: size-weight relationships, energy reserves as glycogen and lipids, sexual maturation patterns, total number of oocytes per female, total and relative fecundity, burrowing behaviour. The physiological and behavioural status of N. diversicolor was consistently disturbed in the larger, most contaminated estuaries (Loire and Seine, Fr.) compared to reference sites (Bay of Bourgneuf, Goyen estuary, Fr.). Many classes of potentially toxic chemicals present in these estuaries most likely contribute to these impairments but food availability may act as a confounding factor, interfering with the potential impact of contaminants. - Fitness, and behaviour in Nereis diversicolor are affected by anthropogenic pressure.

  5. Defense Coastal/Estuarine Research Program 2 (DCERP2)

    Science.gov (United States)

    2013-05-01

    Assessing TMDL effectiveness using flow-adjusted concentrations:  A case study of the Neuse River , North Carolina. Environmental Science & Technology 37...activities, and data collection in the NRE Basin and New River by local stakeholder groups. Defense Coastal/Estuarine Research Program (DCERP) Monitoring...relationships between light penetration and solids/chl a levels. ArcGIS and spatial statistics will be used to estimate average bathymetric areas

  6. Coastal and estuarine resources of Bangladesh: management and conservation issues

    Directory of Open Access Journals (Sweden)

    Abu Hena M. Kamal

    2009-07-01

    Full Text Available The coastal area of Bangladesh includes a number of bays into which different types of rivers empty, creating an estuarine ecosystem adjacent to the shore. The main estuarine systems are Brahmaputra-Megna (Gangetic delta, Karnaphuly, Matamuhuri, Bakkhali and Naf rivers, which are comprised of mangroves, salt marshes, seagrass, seaweeds, fisheries, coastal birds, animals, coral reefs, deltas, salt beds, minerals and sand dunes. The estuarine environment, which serves as feeding, breeding and nursery grounds for a variety of animals, varies according to the volume of discharge of the river and tidal range. It is highly productive in terms of nutrient input from different sources that promotes other living resources in the estuaries. Drought conditions exist during the winter months, i.e. November to February, and effective rainfall is confined to the monsoon period, i.e. May to June. Changes in salinity and turbidity depend on annual rainfall. The colour of most estuarine waters is tea brown or brown due to heavy outflows during the monsoon. The tidal mixing and riverine discharge governs the distribution of the hydrological parameters. The pH of these waters is reported to be slightly alkaline (>7.66 and dissolved oxygen (<6.0 mg/l shows an inverse relationship to temperature. Studies of plankton have indicated two periods of maximum abundance, i.e. February-March and August-September. The abundance of fish and shrimp larvae varies in number and composition with season. Many marine and freshwater species are available in various types of coastal brackish water, which depend on monsoonal activities and local environmental conditions.

  7. Defense Coastal/Estuarine Research Program (DCERP) Strategic Plan

    Science.gov (United States)

    2007-09-01

    availability to phytoplankton in the water column, as well as to benthic microalgae, macroalgae , and seagrasses in bottom waters (Gallegos et al., 2005...further another of MCBCL’s key management objectives for meeting the requirements of the CWA. How wetlands may be utilized for water treatment ...Regulations Appendix B Prioritized list of MCBCL’s conservation and water quality needs Defense Coastal/Estuarine Research Program (DCERP) Strategic

  8. Paradigms in the Recovery of Estuarine and Coastal Ecosystems

    OpenAIRE

    Duarte, Carlos M.; Borja, Ángel; Carstensen, Jacob; Elliott, Michael S.; Krause-Jensen, Dorte; Marbà, Núria

    2015-01-01

    © 2013, Coastal and Estuarine Research Federation. Following widespread deterioration of coastal ecosystems since the 1960s, current environmental policies demand ecosystem recovery and restoration. However, vague definitions of recovery and untested recovery paradigms complicate efficient stewardship of coastal ecosystems. We critically examine definitions of recovery and identify and test the implicit paradigms against well-documented cases studies based on a literature review. The study hi...

  9. Long-term fluctuations in population of Semibalanus balanoides (L. (Crustacea in the estuarine zone of the Kola Bay

    Directory of Open Access Journals (Sweden)

    Svitina V. S.

    2017-06-01

    Full Text Available The intertidal population of the barnacles Semibalanus balanoides has been explored in the estuarine zone of the Tuloma River at the end of the Kola Bay for the first time. Barnacles S. balanoides are typical species for the littoral zone of the northern seas, they populate both the high and low salinity areas along the coast of the Barents Sea. The ecology and distribution of barnacle population in estuarine intertidal zones of the Barents Sea are not studied previously, and under the critical salinity conditions of any estuary, in particular. The investigation have been carried out on the littoral of the western (left shore of the southern tribe of the Kola Bay – the estuary section from the Tuloma bridge to the Cape Elovy. The studied site is a sandy-boulder beach with stony bars, its length is about 1 150 m, the area is about 126 500 m2. Counting the number of S. balanoides in clusters has been performed on site (without removal of the copepods from the population by the standard method for intertidal sampling. Simultaneously with the defining the number of barnacles for the period 2003–2014, the measurements of salinity and temperature of water and air have been made. The peculiarity of the estuarine barnacle population is their complete absence in the upper horizon of the littoral, and in the middle and the lower horizons they are found only within the channels of the littoral streams (3–20 specimens in the sample. For the first time the abundance and biomass of barnacles S. balanoides in this estuarine population has been determined, and the causes of their narrow-local distribution on the estuary littoral of the Tuloma River have been revealed. The main ecological factors determining the abundance and specific distribution of barnacles under the conditions of estuarine littoral have been established. The regular increase in the density of adult S. balanoides settlements along the gradient of water salinity from the Tuloma River to

  10. Sediment Chemistry and Toxicity in Barnegat Bay, New Jersey: Pre- and Post- Hurricane Sandy, 2012-2013.

    Science.gov (United States)

    Romanok, Kristin M.; Szabo, Zoltan; Reilly, Timothy J.; Defne, Zafer; Ganju, Neil K.

    2016-01-01

    Hurricane Sandy made landfall in Barnegat Bay, October, 29, 2012, damaging shorelines and infrastructure. Estuarine sediment chemistry and toxicity were investigated before and after to evaluate potential environmental health impacts and to establish post-event baseline sediment-quality conditions. Trace element concentrations increased throughout Barnegat Bay up to two orders of magnitude, especially north of Barnegat Inlet, consistent with northward redistribution of silt. Loss of organic compounds, clay, and organic carbon is consistent with sediment winnowing and transport through the inlets and sediment transport modeling results. The number of sites exceeding sediment quality guidance levels for trace elements tripled post-Sandy. Sediment toxicity post-Sandy was mostly unaffected relative to pre-Sandy conditions, but at the site with the greatest relative increase for trace elements, survival rate of the test amphipod decreased (indicating degradation). This study would not have been possible without comprehensive baseline data enabling the evaluation of storm-derived changes in sediment quality.

  11. Effect of thermal shock on developmental stages of estuarine fish. Final report

    International Nuclear Information System (INIS)

    Dean, J.M.

    1978-12-01

    Physiological data and ecological data show that the few estuarine spawners have a higher thermal tolerance in the embryonic and larval stages than do the freshwater, coastal, or oceanic spawning species. However, since all three groups (freshwater, estuarine, and oceanic spawners) occupy the estuary and coastal waters at different times of the year, knowledge of their physiology and ecology at different developmental or life cycle stages is critical for estuarine management decisions

  12. Progress and challenges in coupled hydrodynamic-ecological estuarine modeling

    Science.gov (United States)

    Ganju, Neil K.; Brush, Mark J.; Rashleigh, Brenda; Aretxabaleta, Alfredo L.; del Barrio, Pilar; Grear, Jason S.; Harris, Lora A.; Lake, Samuel J.; McCardell, Grant; O'Donnell, James; Ralston, David K.; Signell, Richard P.; Testa, Jeremy; Vaudrey, Jamie M. P.

    2016-01-01

    Numerical modeling has emerged over the last several decades as a widely accepted tool for investigations in environmental sciences. In estuarine research, hydrodynamic and ecological models have moved along parallel tracks with regard to complexity, refinement, computational power, and incorporation of uncertainty. Coupled hydrodynamic-ecological models have been used to assess ecosystem processes and interactions, simulate future scenarios, and evaluate remedial actions in response to eutrophication, habitat loss, and freshwater diversion. The need to couple hydrodynamic and ecological models to address research and management questions is clear because dynamic feedbacks between biotic and physical processes are critical interactions within ecosystems. In this review, we present historical and modern perspectives on estuarine hydrodynamic and ecological modeling, consider model limitations, and address aspects of model linkage, skill assessment, and complexity. We discuss the balance between spatial and temporal resolution and present examples using different spatiotemporal scales. Finally, we recommend future lines of inquiry, approaches to balance complexity and uncertainty, and model transparency and utility. It is idealistic to think we can pursue a “theory of everything” for estuarine models, but recent advances suggest that models for both scientific investigations and management applications will continue to improve in terms of realism, precision, and accuracy.

  13. Managing bay and estuarine ecosystems for multiple services

    Science.gov (United States)

    Needles, Lisa A.; Lester, Sarah E.; Ambrose, Richard; Andren, Anders; Beyeler, Marc; Connor, Michael S.; Eckman, James E.; Costa-Pierce, Barry A.; Gaines, Steven D.; Lafferty, Kevin D.; Lenihan, Junter S.; Parrish, Julia; Peterson, Mark S.; Scaroni, Amy E.; Weis, Judith S.; Wendt, Dean E.

    2013-01-01

    Managers are moving from a model of managing individual sectors, human activities, or ecosystem services to an ecosystem-based management (EBM) approach which attempts to balance the range of services provided by ecosystems. Applying EBM is often difficult due to inherent tradeoffs in managing for different services. This challenge particularly holds for estuarine systems, which have been heavily altered in most regions and are often subject to intense management interventions. Estuarine managers can often choose among a range of management tactics to enhance a particular service; although some management actions will result in strong tradeoffs, others may enhance multiple services simultaneously. Management of estuarine ecosystems could be improved by distinguishing between optimal management actions for enhancing multiple services and those that have severe tradeoffs. This requires a framework that evaluates tradeoff scenarios and identifies management actions likely to benefit multiple services. We created a management action-services matrix as a first step towards assessing tradeoffs and providing managers with a decision support tool. We found that management actions that restored or enhanced natural vegetation (e.g., salt marsh and mangroves) and some shellfish (particularly oysters and oyster reef habitat) benefited multiple services. In contrast, management actions such as desalination, salt pond creation, sand mining, and large container shipping had large net negative effects on several of the other services considered in the matrix. Our framework provides resource managers a simple way to inform EBM decisions and can also be used as a first step in more sophisticated approaches that model service delivery.

  14. Influence of macrobenthos on chemical diagenesis of marine sediments

    Energy Technology Data Exchange (ETDEWEB)

    Aller, R.C.

    1977-05-01

    Diagenetic reactions involving the decomposition of organic matter and the dissolution, mobilization, and reprecipitation of metals sensitive to oxidation-reduction reactions, are most intense and rapid in the upper 1 m and especially the upper 10 cm of marine sediment. It is in this upper zone where most benthic organisms live and interact with sediments and where exchange rates of dissolved and particulate material between sediment and overlying water are largely determined. In Long Island Sound, U.S.A., both spatial and temporal trends in sediment chemistry and the flux of material out of the bottom demonstrate the control of diagenesis by bottom fauna. /sup 234/Th//sup 238/U disequilibrium studies demonstrate that particle reworking rates near the sediment-water interface vary both temporally and spatially in the Sound. The most rapid reworking occurs in protobranch-inhabited bottom areas as do the highest /sup 234/Th inventories. Excess /sup 234/Th profiles in the sediment allow determination of the rates of selected diagenetic reactions, such as Mn/sup + +/ production, near the sediment surface. Both the /sup 234/Th disequilibrium and flux measurements indicate that intra-estuarine redistribution of metals continually takes place.

  15. Dating sediment cores from Hudson River marshes

    International Nuclear Information System (INIS)

    Robideau, R.; Bopp, R.F.

    1993-01-01

    There are several methods for determining sediment accumulation rates in the Hudson River estuary. One involves the analysis of the concentration of certain radionuclides in sediment core sections. Radionuclides occur in the Hudson River as a result of: natural sources, fallout from nuclear weapons testing and low level aqueous releases from the Indian Point Nuclear Power Facility. The following radionuclides have been studied in the authors work: Cesium-137, which is derived from global fallout that started in the 1950's and has peaked in 1963. Beryllium-7, a natural radionuclide with a 53 day half-life and found associated with very recently deposited sediments. Another useful natural radionuclide is Lead-210 derived from the decay of Radon-222 in the atmosphere. Lead-210 has a half-life of 22 years and can be used to date sediments up to about 100 years old. In the Hudson River, Cobalt-60 is a marker for Indian Point Nuclear Reactor discharges. The author's research involved taking sediment core samples from four sites in the Hudson River Estuarine Research Reserve areas. These core samples were sectioned, dried, ground and analyzed for the presence of radionuclides by the method of gamma-ray spectroscopy. The strength of each current pulse is proportional to the energy level of the gamma ray absorbed. Since different radionuclides produce gamma rays of different energies, several radionuclides can be analyzed simultaneously in each of the samples. The data obtained from this research will be compared to earlier work to obtain a complete chronology of sediment deposition in these Reserve areas of the river. Core samples may then by analyzed for the presence of PCB's, heavy metals and other pollutants such as pesticides to construct a pollution history of the river

  16. Gross Nitrogen Mineralization in Surface Sediments of the Yangtze Estuary

    Science.gov (United States)

    Liu, Min; Li, Xiaofei; Yin, Guoyu; Zheng, Yanling; Deng, Fengyu

    2016-01-01

    Nitrogen mineralization is a key biogeochemical process transforming organic nitrogen to inorganic nitrogen in estuarine and coastal sediments. Although sedimentary nitrogen mineralization is an important internal driver for aquatic eutrophication, few studies have investigated sedimentary nitrogen mineralization in these environments. Sediment-slurry incubation experiments combined with 15N isotope dilution technique were conducted to quantify the potential rates of nitrogen mineralization in surface sediments of the Yangtze Estuary. The gross nitrogen mineralization (GNM) rates ranged from 0.02 to 5.13 mg N kg-1 d-1 in surface sediments of the study area. The GNM rates were generally higher in summer than in winter, and the relative high rates were detected mainly at sites near the north branch and frontal edge of this estuary. The spatial and temporal distributions of GNM rates were observed to depend largely on temperature, salinity, sedimentary organic carbon and nitrogen contents, and extracellular enzyme (urease and L-glutaminase) activities. The total mineralized nitrogen in the sediments of the Yangtze Estuary was estimated to be about 6.17 × 105 t N yr-1, and approximately 37% of it was retained in the estuary. Assuming the retained mineralized nitrogen is totally released from the sediments into the water column, which contributed 12–15% of total dissolved inorganic nitrogen (DIN) sources in this study area. This result indicated that the mineralization process is a significant internal nitrogen source for the overlying water of the Yangtze Estuary, and thus may contribute to the estuarine and coastal eutrophication. PMID:26991904

  17. Environmental risk assessment of triclosan and ibuprofen in marine sediments using individual and sub-individual endpoints.

    Science.gov (United States)

    Pusceddu, F H; Choueri, R B; Pereira, C D S; Cortez, F S; Santos, D R A; Moreno, B B; Santos, A R; Rogero, J R; Cesar, A

    2018-01-01

    The guidelines for the Environmental Risk Assessment (ERA) of pharmaceuticals and personal care products (PPCP) recommend the use of standard ecotoxicity assays and the assessment of endpoints at the individual level to evaluate potential effects of PPCP on biota. However, effects at the sub-individual level can also affect the ecological fitness of marine organisms chronically exposed to PPCP. The aim of the current study was to evaluate the environmental risk of two PPCP in marine sediments: triclosan (TCS) and ibuprofen (IBU), using sub-individual and developmental endpoints. The environmental levels of TCS and IBU were quantified in marine sediments from the vicinities of the Santos submarine sewage outfall (Santos Bay, São Paulo, Brazil) at 15.14 and 49.0 ng g -1 , respectively. A battery (n = 3) of chronic bioassays (embryo-larval development) with a sea urchin (Lytechinus variegatus) and a bivalve (Perna perna) were performed using two exposure conditions: sediment-water interface and elutriates. Moreover, physiological stress through the Neutral Red Retention Time Assay (NRRT) was assessed in the estuarine bivalve Mytella charruana exposed to TCS and IBU spiked sediments. These compounds affected the development of L. variegatus and P. perna (75 ng g -1 for TCS and 15 ng g -1 for IBU), and caused a significant decrease in M. charruana lysosomal membrane stability at environmentally relevant concentrations (0.08 ng g -1 for TCS and 0.15 ng g -1 for IBU). Chemical and ecotoxicological data were integrated and the risk quotient estimated for TCS and IBU were higher than 1.0, indicating a high environmental risk of these compounds in sediments. These are the first data of sediment risk assessment of pharmaceuticals and personal care products of Latin America. In addition, the results suggest that the ERA based only on individual-level and standard toxicity tests may overlook other biological effects that can affect the health of marine organisms

  18. Geochemical assessment of heavy metals pollution in surface sediments of Vellar and Coleroon estuaries, southeast coast of India.

    Science.gov (United States)

    Nethaji, S; Kalaivanan, R; Arya Viswam; Jayaprakash, M

    2017-02-15

    Surface sediments were collected from Vellar and Coleroon estuaries for determine sediment texture, calcium carbonate, organic matter and heavy metals. Pollution indices such as pollution load index (PLI), contamination factor (CF), enrichment factor (EF) and geo-accumulation index (I geo ) were done for this study to know the level of heavy metals pollution in the estuarine ecosystem. Pearson correlation matrix and factor were used to assess the relationship and source of heavy metals in the estuarine sediments. The results of PLI values reveal that the study area was polluted by all the heavy metals. The calculated values of CF and I geo followed the decreasing order Cu>Ni>Pb>Co>Cr>Zn>Mn>Fe and illustrate that Cu, Ni and Pb are contaminated due to anthropogenic sources in both estuaries. Correlation and factor analysis suggest that FeMn oxyhydroxides, organic matter and fine particles are responsible for high concentration of heavy metals. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Natural radionuclides in the Brazilian coast region: 1. Estuarine complex Cananeia-Iguape, Sao Paulo State

    Energy Technology Data Exchange (ETDEWEB)

    Franca, E.J. de; Ferreira, Fabiano S.; Silva Neto, Paulo C.; Farias, Emerson E.G. de; Figueira, Rubens C.L.; Ribeiro, Andreza P., E-mail: ejfranca@cnen.gov.br, E-mail: biologofabiano10@gmail.com, E-mail: ptpoli@yahoo.com.br, E-mail: emersonemiliano@yahoo.com.br [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil)

    2015-07-01

    Mangrove forests are of utmost important ecosystems for biogeochemical transport processes in a global scale because of the preferential transport via sediments and organic matter from continents to oceans. Such ecosystems are the richest biodiversity areas, in which bioaccumulation of chemical substances can be expected for some species, in this case, there is a lack of knowledge of natural radionuclides accumulation in mangrove vegetation. This work encompasses the first results obtained for the Estuarine Complex Cananeia-Iguape, a peculiar coast area of the Sao Paulo State, Brazil. In 2011, leaf samples of Rhyzophora mangle and Laguncularia racemosa trees with perimeter at the breast height higher than 15 cm were collected in the conservation unit Parque Estadual Ilha do Cardoso. Sample preparation consisted of leaf washing, oven-drying, milling in porcelain mortar at the particle size lower than 0.5 mm. Portions of 10 g were transferred to polyethylene vials of appropriate geometry for the analysis by high resolution gamma-ray spectrometry. Reference materials were analyzed together to evaluate the quality of the analytical procedure. K-40 was preferentially allocated in leaves. Some accumulation in leaves was noticed for Pb-210 and Ac-228 depending on the species, indicating differences of radionuclide distribution in the mangrove vegetation. (author)

  20. Characterisation of the suspended particulate matter in a stratified estuarine environment employing complementary techniques

    Science.gov (United States)

    Thomas, Luis P.; Marino, Beatriz M.; Szupiany, Ricardo N.; Gallo, Marcos N.

    2017-09-01

    The ability to predict the sediment and nutrient circulation within estuarine waters is of significant economic and ecological importance. In these complex systems, flocculation is a dynamically active process that is directly affected by the prevalent environmental conditions. Consequently, the floc properties continuously change, which greatly complicates the characterisation of the suspended particle matter (SPM). In the present study, three different techniques are combined in a stratified estuary under quiet weather conditions and with a low river discharge to search for a solution to this problem. The challenge is to obtain the concentration, size and flux of suspended elements through selected cross-sections using the method based on the simultaneous backscatter records of 1200 and 600 kHz ADCPs, isokinetic sampling data and LISST-25X measurements. The two-ADCP method is highly effective for determining the SPM size distributions in a non-intrusive way. The isokinetic sampling and the LISST-25X diffractometer offer point measurements at specific depths, which are especially useful for calibrating the ADCP backscatter intensity as a function of the SPM concentration and size, and providing complementary information on the sites where acoustic records are not available. Limitations and potentials of the techniques applied are discussed.

  1. Natural radionuclides in the Brazilian coast region: 1. Estuarine complex Cananeia-Iguape, Sao Paulo State

    International Nuclear Information System (INIS)

    Franca, E.J. de; Ferreira, Fabiano S.; Silva Neto, Paulo C.; Farias, Emerson E.G. de; Figueira, Rubens C.L.; Ribeiro, Andreza P.

    2015-01-01

    Mangrove forests are of utmost important ecosystems for biogeochemical transport processes in a global scale because of the preferential transport via sediments and organic matter from continents to oceans. Such ecosystems are the richest biodiversity areas, in which bioaccumulation of chemical substances can be expected for some species, in this case, there is a lack of knowledge of natural radionuclides accumulation in mangrove vegetation. This work encompasses the first results obtained for the Estuarine Complex Cananeia-Iguape, a peculiar coast area of the Sao Paulo State, Brazil. In 2011, leaf samples of Rhyzophora mangle and Laguncularia racemosa trees with perimeter at the breast height higher than 15 cm were collected in the conservation unit Parque Estadual Ilha do Cardoso. Sample preparation consisted of leaf washing, oven-drying, milling in porcelain mortar at the particle size lower than 0.5 mm. Portions of 10 g were transferred to polyethylene vials of appropriate geometry for the analysis by high resolution gamma-ray spectrometry. Reference materials were analyzed together to evaluate the quality of the analytical procedure. K-40 was preferentially allocated in leaves. Some accumulation in leaves was noticed for Pb-210 and Ac-228 depending on the species, indicating differences of radionuclide distribution in the mangrove vegetation. (author)

  2. Methane emission through ebullition from an estuarine mudflat: 2. Field observations and modeling of occurrence probability

    Science.gov (United States)

    Chen, Xi; Schäfer, Karina V. R.; Slater, Lee

    2017-08-01

    Ebullition can transport methane (CH4) at a much faster rate than other pathways, albeit over limited time and area, in wetland soils and sediments. However, field observations present large uncertainties in ebullition occurrences and statistic models are needed to describe the function relationship between probability of ebullition occurrence and water level changes. A flow-through chamber was designed and installed in a mudflat of an estuarine temperate marsh. Episodic increases in CH4 concentration signaling ebullition events were observed during ebbing tides (15 events over 456 ebbing tides) and occasionally during flooding tides (4 events over 455 flooding tides). Ebullition occurrence functions were defined using logistic regression as the relative initial and end water levels, as well as tidal amplitudes were found to be the key functional variables related to ebullition events. Ebullition of methane was restricted by a surface frozen layer during winter; melting of this layer during spring thaw caused increases in CH4 concentration, with ebullition fluxes similar to those associated with large fluctuations in water level around spring tides. Our findings suggest that initial and end relative water levels, in addition to tidal amplitude, partly regulate ebullition events in tidal wetlands, modulated by the lunar cycle, storage of gas bubbles at different depths and seasonal changes in the surface frozen layer. Maximum tidal strength over a few days, rather than hourly water level, may be more closely associated with the possibility of ebullition occurrence as it represents a trade-off time scale in between hourly and lunar periods.

  3. Identifying resuspended sediment in an estuary using the 228Th/232Th activity ratio: the fate of lagoon sediment in the Bega River estuary, Australia

    International Nuclear Information System (INIS)

    Hancock, G.J.

    2000-01-01

    Thorium-series nuclides ( 228 Th and 232 Th) have been used to identify resuspended sediment in the Bega River estuary, south-eastern Australia. A non-conservative increase in concentration of suspended sediment of water in the vicinity of mid-estuary back-flow lagoons was associated with a decrease in the 228 Th/ 232 Th activity ratio (AR) of the suspended sediment. The lagoon sediment is characterized by a low estuarine 228 Th/ 232 Th signature, distinguishing it from freshwater suspended sediment recently delivered to the estuary, and identifying it as the likely source of the additional suspended sediment. Sediment-core 210 TPb profiles show that the lagoons are accumulating sediment, presumably during high river-flow events. However this study indicates that during intervening periods of low flow, 40% of sediment deposited in the lagoons is subsequently resuspended and exported to the lower estuary, and possibly to the ocean. The utility of the 228 Th/ 232 Th AR to quantify sediment resuspension in estuaries is likely to be estuary-dependent, and is controlled by the extent of scavenging of dissolved 228 Th by suspended particles. Copyright (2000) CSIRO Publishing

  4. The morphological development of newly inundated intertidal areas: the mechanisms driving the early evolution of an estuarine environment designed and constructed by humans

    Science.gov (United States)

    Dale, Jonathan; Burgess, Heidi; Cundy, Andrew

    2017-04-01

    elevation excavated during site construction, drained by a series of natural and engineered channels. Results indicate different rates and patterns of sedimentation and resulting morphology across the site. Near the breach continuous sedimentation of > 15cm over a 1 year period was measured, compared to rhythmic periods of accretion and erosion inland. These variations have been related to site design, former land-use and different sediment sources. The evolution of developing creek networks, formed by pluvial action and sediment "piping", are controlled by unconformities found in the sub-surface sediment related to Holocene site evolution. Analysis of the sedimentary processes and subsequent morphological development of these areas provides a new insight into coastal and estuarine evolution in an anthropogenically designed and constructed estuarine environment.

  5. Sediment-stabilizing and Destabilizing Ecoengineering Species from River to Estuary: the Case of the Scheldt System

    Science.gov (United States)

    Selakovic, S.; Cozzoli, F.; Leuven, J.; Van Braeckel, A.; Speybroeck, J.; Kleinhans, M. G.; Bouma, T.

    2017-12-01

    Interactions between organisms and landscape forming processes play an important role in evolution of coastal landscapes. In particular, biota has a strong potential to interact with important geomorphological processes such as sediment dynamics. Although many studies worked towards quantifying the impact of different species groups on sediment dynamics, information has been gathered on an ad hoc base. Depending on species' traits and distribution, functional groups of ecoengineering species may have differential effects on sediment deposition and erosion. We hypothesize that the spatial distributions of sediment-stabilizing and destabilizing species across the channel and along the whole salinity gradient of an estuary partly determine the planform shape and channel-shoal morphology of estuaries. To test this hypothesis, we analyze vegetation and macrobenthic data taking the Scheldt river-estuarine continuum as model ecosystem. We identify species traits with important effects on sediment dynamics and use them to form functional groups. By using linearized mixed modelling, we are able to accurately describe the distributions of the different functional groups. We observe a clear distinction of dominant ecosystem engineering functional groups and their potential effects on the sediment in the river-estuarine continuum. The first results of longitudinal cross section show the highest effects of stabilizing plant species in riverine and sediment bioturbators in weak polyhaline part of continuum. The distribution of functional groups in transverse cross sections shows dominant stabilizing effect in supratidal zone compared to dominant destabilizing effect in the lower intertidal zone. This analysis offers a new and more general conceptualization of distributions of sediment stabilizing and destabilizing functional groups and their potential impacts on sediment dynamics, shoal patterns, and planform shapes in river-estuarine continuum. We intend to test this in future

  6. Sources of heavy metals in sediments of the Hudson River Estuary

    International Nuclear Information System (INIS)

    Williams, S.C.; Simpson, H.J.; Olsen, C.R.; Bopp, R.F.

    1978-01-01

    Sediments in the Hudson Estuary contain zinc, copper and lead from metal pollutants discharged to the harbor in the New York City area, from dispersed sources of contamination introduced upstream, and from natural weathering processes. The magnitude of the contribution from each of these three sources to particular sites can be estimated on the basis of total metal abundances, relative proportions of several metals, and other sediment properties. The pattern of recent heavy-metal contamination in Hudson sediments closely follows the distribution in sediments of 137 Cs which was derived over the past two decades from global fallout and local releases from a commercial nuclear reactor. Several simple empirical corrections related to grain size and mineralogy variations are suggested for comparing heavy-metal contamination levels of sandy continental shelf sediments with fine-grained estuarine and coastal sediments. Iron has little variation in Hudson sediments while manganese is greater in surface sediment of some low-salinity and fresh-water areas than deeper in the sediments, and generally less in the high-salinity area of rapid sediment deposition in New York harbor. Much of the pollutant Cu added to the harbor appears to be rapidly deposited in the sediments. (Auth.)

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

    International Nuclear Information System (INIS)

    Onishi, Y.; Trent, D.S.

    1985-04-01

    The three-dimensional, finite difference model, FLESCOT simulates time-varying movements of flow, turbulent kinetic energy, salinity, water temperature, sediment, and contaminants in estuarine, coastal, and ocean waters. The model was applied to a 106-km (66-mi) reach of the Hudson River estuary in New York between Chelsea and the mouth of the river. It predicted the time-varying, three-dimensional distributions of tidal flow, salinity, three separate groups of sediments (i.e., sand, silt, and clay), and a radionuclide ( 137 Cs) in both dissolved and particulate (those sorbed by sediments) forms for over 40 days. The model also calculated riverbed elevation changes caused by sediment deposition and bed erosion, bed sediment size distribution and armoring, and distributions of the particulate 137 Cs sorbed by sand, silt, and clay in the bed

  8. Changes in N cycling induced by Ulva detritus enrichment of sediments

    DEFF Research Database (Denmark)

    Garcia-Robledo, Emilio; Revsbech, Niels Peter; Risgaard-Petersen, Nils

    2013-01-01

    Macroalgal accumulation and decomposition in shallow water environments typically result in an increase in the organic matter content of the sediment, affecting both benthic metabolism and nutrient dynamics. The present study investigates how a pulse addition of Ulva detritus to estuarine sediment...... of oxygen and nitrate. Nitrification increased significantly in response to enhanced NH4 + supply from decomposition of the Ulva detritus. Aerobic ammonia oxidation exceeded rates of nitrite oxidation, leading to accumulation of NO2 − in the oxic zone of the sediment. Nitrite and NO3 − produced via...... nitrification diffused up to the sediment surface, inducing a net efflux to the water column, and downwards, supporting a high rate of denitrification coupled to nitrification. The present study shows that organic enrichment with Ulva detritus enhances sediment oxygen uptake, nitrification and denitrification...

  9. Sensitivity of the sediment trapping capacity of an estuarine mangrove forest

    NARCIS (Netherlands)

    Willemsen, Pim Wilhelmus Johannes Maria; Horstman, Erik; Borsje, Bastiaan Wijnand; Friess, D.A.; Dohmen-Janssen, Catarine M.

    2016-01-01

    Intertidal mangrove forests exist in a dynamic coastal environment that is increasingly impacted by human interference, leading to habitat fragmentation, reduced habitat quality and changing hydrodynamic and geomorphological conditions. Biophysical feedback mechanisms are essential to maintain

  10. Partitioning of metals in different binding phases of tropical estuarine sediments: importance of metal chemistry

    Digital Repository Service at National Institute of Oceanography (India)

    Chakraborty, P.; Chakraborty, S.; Vudamala, K.; Sarkar, Arindam; Nath, B.N.

    association with Fe/Mn oxide phases followed by Ni and Cu. Faster k-w of Cu (II) (1×109 s-1) increased the rate of complex formation of Cu2+ ion with ligand in the organic phases. The Cu–ligand (from organic phase...

  11. HYDROGEN CONCENTRATIONS IN SULFATE-REDUCING ESTUARINE SEDIMENTS DURING PCE DEHALOGENATION

    Science.gov (United States)

    Despite recent progress made evaluating the role of hydrogen (H2) as a key electron donor in the anaerobic remediation of chloroethenes, few studies have focused on the evaluation of hydrogen thresholds relative to reductive dehalogenation in sulfidogenic environments. Competitio...

  12. A multi-method approach for the study of lanthanum speciation in coastal and estuarine sediments

    Digital Repository Service at National Institute of Oceanography (India)

    Chakraborty, P.; Babu, P.V.R.; Sarma, V.V.

    ) in different fields (agricultural field, water treatment technology, nuclear industry, glass industry and medicine manufacturing industry) (Guo, 1987; Zhang et al. 1988; Eisenbud and Paschoa, 1989; Tribe et al. 1990; Buckingham et al. 1995) is expected... through the displacement or replacement of calcium in different cell functions and also its high affinity for phosphate groups of biological macromolecules. La 3+ ion usually prevents the influx of Ca 2+ ion and competes for available binding sites...

  13. (Bio)degradation of RDX and HMX in Marine/Estuarine Water and Sediments

    Science.gov (United States)

    2006-09-01

    four fungal strains Rhodotorula sp . HAW-OCF1, Bullera sp . HAW-OCF2, Acremonium sp . HAW-OCF3 and Penicillium sp . HAW-OCF5, were isolated as RDX...represent four novel species of Shewanella described as follows: Shewanella sediminis sp . nov.: Strain HAW-EB3T contains lysine decarboxylase that is...We proposed Shewanella sediminis sp . nov. with HAW-EB3T (= NCIMB 14036T = DSM 17055T) as the type strain (Zhao et al. 2005). Shewanella halifaxensis

  14. Arsenic enrichment in estuarine sediments-impact of iron and manganese mining

    Digital Repository Service at National Institute of Oceanography (India)

    Nair, M.; Joseph, T.; Balachandran, K.K.; Nair, K.K.C.; Paimpillii, J.S.

    River Mandovi and Zuari, Goa (west coast of India) are flowing through iron and manganese mining areas and are heavily used for iron and manganese ore transport. This region generates 25-30 million tons of mining rejects per year. The iron ore...

  15. Fungal phylogenetic diversity in estuarine sediments of Gautami Godavari River, Andhra Pradesh, India

    Digital Repository Service at National Institute of Oceanography (India)

    Khandavilli, R.; Meena, R.; Shenoy, B.D.

    reservoir which has a huge potential for biotechnological products such as new medicines, enzymes, novel pathways in the organisms (Jensen & Fenical 1994). Our literature review (detailed in the discussion section) suggested that there have been few... processed to extract DNA using ZR Fungal/Bacterial DNA MiniPrep (Zymo Research, Catalogue number D6005) according to manufacturer's protocol. DNA samples were subjected to PCR amplification of the ITS region in a Mastercycler. The reactions were carried...

  16. Microbial community structure of surface sediments from a tropical estuarine environment using next generation sequencing

    Digital Repository Service at National Institute of Oceanography (India)

    Khandeparker, L.; Kuchi, N.; Kale, D.; Anil, A.C.

    are of nearly identical length (~50 km each), are highly productive and dynamic systems and have wide mouth regions and longer flushing periods. In this study, Chicalim (15°24'10.92"N, 73°51'8.55"E) and Siridao (15°25'41.89"N, 73°52'38.84"E) were sampled..., Australia). The DNA was extracted using bead beating and column purification which was performed according to the manufacturer's guidelines. The metagenomic DNA was quantified by Eppendorf-Biospectrometer, and run on 0.8% agarose gel. The gel was viewed...

  17. Toxicity and bioaccumulation of sediment-associated silvernanoparticles in the estuarine polychaete, Nereis (Hediste) diversicolor

    DEFF Research Database (Denmark)

    Cong, Yi; Banta, Gary Thomas; Selck, Henriette

    2014-01-01

    damage (comet assay tail moment and tail DNA intensity %) of Nereis coelomocytes increased in a concentration-dependent manner in all three Ag treatments. Ag NP treatments were more toxic than aqueous Ag for all toxicity endpoints, even though bioaccumulation did not differ significantly among Ag forms...

  18. Suspended sediment diffusion mechanisms in the Yangtze Estuary influenced by wind fields

    Science.gov (United States)

    Wang, Lihua; Zhou, Yunxuan; Shen, Fang

    2018-01-01

    The complexity of suspended sediment concentration (SSC) distribution and diffusion has been widely recognized because it is influenced by sediment supply and various hydrodynamic forcing conditions that vary over space and over time. Sediment suspended by waves and transported by currents are the dominant sediment transport mechanisms in estuarine and coastal areas. However, it is unclear to what extent the SSC distribution is impacted by each hydrodynamic factor. Research on the quantitative influence of wind fields on the SSC diffusion range will contribute to a better understanding of the characteristics of sediment transport change and sedimentary geomorphic evolution. This study determined SSC from three Envisat Medium-Resolution Imaging Spectrometer acquisitions, covering the Yangtze Estuary and adjacent water area under the same season and tidal conditions but with varying wind conditions. SSC was examined based on the Semi-Empirical Radiative Transfer model, which has been well validated with the observation data. Integrating the corresponding wind field information from European Centre for Medium-Range Weather Forecasts further facilitated the discussion of wind fields affecting SSC, and in turn the influence of water and suspended sediment transportation and diffusion in the Yangtze estuarine and coastal area. The results demonstrated that the SSC present much more distinctive fluvial features in the inner estuary and wind fields are one of the major factors controlling the range of turbid water diffusion.

  19. Contribution of radioactive tracers to sediment transport study in fluvial flows

    International Nuclear Information System (INIS)

    Wilson Junior, G.

    1995-01-01

    The uses of radioactive tracers in sediment transport studies are presented in this report to evidence the importance of: Open channel researches, to describe field applications in waterways; Simultaneous utilization of classical methods and radiotracer techniques, in fluvial and estuarine environments; Development of radiotracers techniques applied in dynamic sedimentology. The report illustrated with some experiments carried out in Brazil and France, in open channel and natural flows. (author). 5 refs, 4 figs

  20. CHEMOSENSORY ATTRACTION OF ZOOSPORES OF THE ESTUARINE DINOFLAGELLATES, PFIESTERIA PISCICIDA AND P. SHUMWAYAE, TO FINFISH MUCUS AND EXCRETA. (R825551)

    Science.gov (United States)

    Toxic strains of the estuarine dinoflagellates, Pfiesteria piscicida and P. shumwayae, can cause fish death and disease, whereas other estuarine `lookalike' species such as cryptoperidiniopsoids have not been ichthyotoxic under ecologically rel...

  1. Microplastics in sediments of the Changjiang Estuary, China.

    Science.gov (United States)

    Peng, Guyu; Zhu, Bangshang; Yang, Dongqi; Su, Lei; Shi, Huahong; Li, Daoji

    2017-06-01

    Microplastics are plastics that measure less than 5 mm in diameter. They enter the marine environment as primary sources directly from industrial uses, as well as secondary sources resulting from the degradation of large plastic debris. To improve the knowledge of microplastic pollution in China, we investigated samples from 53 estuarine sediment locations collected with a box corer within the Changjiang Estuary. Microplastics (studies using the same quantification method. The identification of microplastics raises the awareness of microplastic pollution from drainage systems. The prevalence of microplastic pollution calls for monitoring microplastics at a national scale on a regular basis. Copyright © 2016. Published by Elsevier Ltd.

  2. Statistical validation of the model of diffusion-convection (MDC) of 137Cs for the assessment of recent sedimentation rates in coastal systems

    International Nuclear Information System (INIS)

    Paulo Alves de Lima Ferreira; Eduardo Siegle; Michel Michaelovitch de Mahiques; Rubens Cesar Lopes Figueira; Carlos Augusto Franca Schettini

    2015-01-01

    This study aimed the validation of the model of diffusion-convection (MDC) of 137 Cs for the calculation of recent sedimentation rates in 13 sedimentary cores of two Brazilian coastal systems, the Cananeia-Iguape and Santos-Sao Vicente estuarine systems. The MDC covers key factors responsible for 137 Cs vertical migration in sediments: its diffusion to the interstitial water and the vertical convection of this water through the sediments. This study successfully validated the MDC use to determine sedimentation rates, which was statistically validated not only with 210 Pb xs (unsupported 210 Pb) models, widely used in oceanographic studies, but also by literature values for those regions. (author)

  3. Mechanisms for accumulation and migration of technetium-99 in saltmarsh sediments

    International Nuclear Information System (INIS)

    Wigley, F.

    2000-06-01

    This thesis describes the development of analytical methods for both the bulk determination of 99 Tc, and determination of 99 Tc in sequential extracts from sediments. These methods have been used to collect data, which, along with trace and major element data have been used to interpret the mechanisms for 99 Tc input, migration and accumulation in saltmarshes. The inventory of 99 Tc stored in the Thornflatt Saltmarsh, Esk Estuary has also been determined. The routine determination of 99 Tc in bulk samples uses 99m Tc as a yield monitor. Samples are ignited stepwise to 550 deg. C and the 99 Tc is extracted using 8M nitric acid. Many contaminants are precipitated with Fe(OH) 3 and the Tc in the supernant is pre-concentrated and further purified using anion-exchange chromatography. Final separation of Tc from Ru is achieved by extraction of Tc into 5% TnOA in xylene from 2M sulphuric acid. The yield is determined by γ-spectrometric analysis of 99m Tc. Determination of 99 Tc is made by liquid scintillation counting. Typical recoveries are in the order of 70-95% and the method has a detection limit of 1.7 Bq/kg for a sample size of 10g. Determination of Tc in sequential extracts uses operationally defined procedures to extract: exchangeable Tc, reducible Tc and oxidisable Tc. An initial water wash is used to extract any occluded Tc and a final leach in 8 M nitric acid is used to dissolve any residual Tc. The isolation of 99 Tc uses TEVA resin for Extracts 1-4 and the decontamination procedure developed for bulk analysis for Extract 5. 99m Tc was used as a yield monitor, and determination of 99 Tc is by liquid scintillation counting. Limits of detection were dependent on the amount of 99m Tc tracer used but were found to be as low as 2.4 Bq/kg for a sample size of 2g. A study was made of the mechanisms responsible for the accumulation and migration of Tc in estuarine sediments using sediments collected from saltmarshes at Thornflatt, Carlaverock and the Ribble Estuary

  4. PCBs and DDE in tree swallow (Tachycineta bicolor) eggs and nestlings from an estuarine PCB superfund site, New Bedford Harbor, MA, U.S.A.

    Science.gov (United States)

    Jayaraman, Saro; Nacci, Diane E.; Champlin, Denise M.; Pruell, Richard J.; Rocha, Kenneth J.; Custer, Christine M.; Custer, Thomas W.; Cantwell, Mark

    2009-01-01

    While breeding tree swallows (Tachycineta bicolor) have been used as biomonitors for freshwater sites, we report the first use of this species to assess contaminant bioaccumulation from estuarine breeding grounds into these aerial insectivores. Eggs and nestlings were collected from nest boxes in a polychlorinated biphenyl (PCB) contaminated estuary, the New Bedford Harbor Superfund site (NBH, Massachusetts, USA), and a reference salt marsh, Fox Hill (FH, Jamestown, Rhode Island, USA). Sediments, eggs, and nestlings were compared on a ng g−1 wet weight basis for total PCBs and DDE (1,1-bis-(4-chlorophenyl)-2,2-dichloroethene), metabolite of DDT (1,1,1-trichloro-2,2-bis-(p-chlorophenyl)ethane). NBH samples contained high concentrations of PCBs compared to FH for sediment (36,500 and 0.2), eggs (11,200 and 323), and nestlings (16,800 and 26). PCB homologue patterns linked tree swallow contamination to NBH sediment. NBH samples were also contaminated with DDE compared to FH for sediment (207 and 0.9) and nestlings (235 and 30) but not for eggs (526 and 488), suggesting both NBH and nonbreeding ground sources for DDE. The relationships between sediment and tree swallow egg and nestling PCBs were similar to those reported for freshwater sites. Like some highly contaminated freshwater sites, NBH PCB bioaccumulation had little apparent effect on reproductive success.

  5. Synergistic effects of diuron and sedimentation on photosynthesis and survival of crustose coralline algae

    Energy Technology Data Exchange (ETDEWEB)

    Harrington, Lindsay [Australian Institute of Marine Science, Townsville, QLD 4810 (Australia) and James Cook University, Townsville, QLD 4811 (Australia)]. E-mail: l.harrington@aims.gov.au; Fabricius, Katharina [Australian Institute of Marine Science, Townsville, QLD 4810 (Australia)]. E-mail: k.fabricius@aims.gov.au; Eaglesham, Geoff [Queensland Health Scientific Services, 39 Kessels Road, Coopers Plains 4108 (Australia); Negri, Andrew [Australian Institute of Marine Science, Townsville, QLD 4810 (Australia)

    2005-07-01

    Effects of short-term exposure to sedimentation and diuron, separately and in combination, on the photophysiology and survival of crustose coralline algae (CCA) were examined in controlled time-course experiments, using pulse-amplitude modulation (PAM) chlorophyll fluorometry. These experiments indicated that the effects of sediments and diuron, when applied in isolation, were often reversible, with recovery time dependant upon sediment type and diuron concentration. Exposure to fine (<63 {mu}m grain size), nutrient-rich estuarine sediments reduced effective quantum yields ({delta}F/F {sub m'}) of photosystem II in CCA species more than exposure to the same amount of fine (<63 {mu}m grain size) calcareous sediments. Significant inhibition of photosynthesis ({delta}F/F {sub m'}) was also observed at diuron concentrations 2.9 {mu}g L{sup -1}. Fine estuarine sediments in combination with 0.79 {mu}g L{sup -1} dissolved diuron, caused yields ({delta}F/F {sub m'}) to drop by 60% compared with controls after 24 h. The combined exposure to sediments and diuron also retarded recovery, thus {delta}F/F {sub m'} values were still only 60% of the controls after 9 days recovery in clean seawater. Mortality of CCA was observed in some fragments treated with combinations of sediment and diuron. Our results suggest that sediment deposition and exposure to diuron can negatively affect the photosynthetic activity of CCA, with sedimentation stress being significantly enhanced by the presence of trace concentrations of diuron.

  6. The development and application of landscape evolution models to coupled coast-estuarine environments

    Science.gov (United States)

    Morris, Chloe; Coulthard, Tom; Parsons, Daniel R.; Manson, Susan; Barkwith, Andrew

    2017-04-01

    Landscape Evolution Models (LEMs) are proven to be useful tools in understanding the morphodynamics of coast and estuarine systems. However, perhaps owing to the lack of research in this area, current models are not capable of simulating the dynamic interactions between these systems and their co-evolution at the meso-scale. Through a novel coupling of numerical models, this research is designed to explore coupled coastal-estuarine interactions, controls on system behaviour and the influence that environmental change could have. This will contribute to the understanding of the morphodynamics of these systems and how they may behave and evolve over the next century in response to climate changes, with the aim of informing management practices. This goal is being achieved through the modification and coupling of the one-line Coastline Evolution Model (CEM) with the hydrodynamic LEM CAESAR-Lisflood (C-L). The major issues faced with coupling these programs are their differing complexities and the limited graphical visualisations produced by the CEM that hinder the dissemination of results. The work towards overcoming these issues and reported here, include a new version of the CEM that incorporates a range of more complex geomorphological processes and boasts a graphical user interface that guides users through model set-up and projects a live output during model runs. The improved version is a stand-alone tool that can be used for further research projects and for teaching purposes. A sensitivity analysis using the Morris method has been completed to identify which key variables, including wave climate, erosion and weathering values, dominate the control of model behaviour. The model is being applied and tested using the evolution of the Holderness Coast, Humber Estuary and Spurn Point on the east coast of England (UK), which possess diverse geomorphologies and complex, co-evolving sediment pathways. Simulations using the modified CEM are currently being completed to

  7. Modelling the morphodynamics and co-evolution of coast and estuarine environments

    Science.gov (United States)

    Morris, Chloe; Coulthard, Tom; Parsons, Daniel R.; Manson, Susan; Barkwith, Andrew

    2017-04-01

    The morphodynamics of coast and estuarine environments are known to be sensitive to environmental change and sea-level rise. However, whilst these systems have received considerable individual research attention, how they interact and co-evolve is relatively understudied. These systems are intrinsically linked and it is therefore advantageous to study them holistically in order to build a more comprehensive understanding of their behaviour and to inform sustainable management over the long term. Complex environments such as these are often studied using numerical modelling techniques. Inherent from the limited research in this area, existing models are currently not capable of simulating dynamic coast-estuarine interactions. A new model is being developed through coupling the one-line Coastline Evolution Model (CEM) with CAESAR-Lisflood (C-L), a hydrodynamic Landscape Evolution Model. It is intended that the eventual model be used to advance the understanding of these systems and how they may evolve over the mid to long term in response to climate change. In the UK, the Holderness Coast, Humber Estuary and Spurn Point system offers a diverse and complex case study for this research. Holderness is one of the fastest eroding coastlines in Europe and research suggests that the large volumes of material removed from its cliffs are responsible for the formation of the Spurn Point feature and for the Holocene infilling of the Humber Estuary. Marine, fluvial and coastal processes are continually reshaping this system and over the next century, it is predicted that climate change could lead to increased erosion along the coast and supply of material to the Humber Estuary and Spurn Point. How this manifests will be hugely influential to the future morphology of these systems and the existence of Spurn Point. Progress to date includes a new version of the CEM that has been prepared for integration into C-L and includes an improved graphical user interface and more complex

  8. Habitat loss and gain: Influence on habitat attractiveness for estuarine fish communities

    Science.gov (United States)

    Amorim, Eva; Ramos, Sandra; Elliott, Michael; Franco, Anita; Bordalo, Adriano A.

    2017-10-01

    Habitat structure and complexity influence the structuring and functioning of fish communities. Habitat changes are one of the main pressures affecting estuarine systems worldwide, yet the degree and rate of change and its impact on fish communities is still poorly understood. In order to quantify historical modifications in habitat structure, an ecohydrological classification system using physiotopes, i.e. units with homogenous abiotic characteristics, was developed for the lower Lima estuary (NW Portugal). Field data, aerial imagery, historical maps and interpolation methods were used to map input variables, including bathymetry, substratum (hard/soft), sediment composition, hydrodynamics (current velocity) and vegetation coverage. Physiotopes were then mapped for the years of 1933 and 2013 and the areas lost and gained over the 80 years were quantified. The implications of changes for the benthic and demersal fish communities using the lower estuary were estimated using the attractiveness to those communities of each physiotope, while considering the main estuarine habitat functions for fish, namely spawning, nursery, feeding and refuge areas and migratory routes. The lower estuary was highly affected due to urbanisation and development and, following a port/harbour expansion, its boundary moved seaward causing an increase in total area. Modifications led to the loss of most of its sandy and saltmarsh intertidal physiotopes, which were replaced by deeper subtidal physiotopes. The most attractive physiotopes for fish (defined as the way in which they supported the fish ecological features) decreased in area while less attractive ones increased, producing an overall lower attractiveness of the studied area in 2013 compared to 1933. The implications of habitat alterations for the fish using the estuary include potential changes in the nursery carrying capacity and the functioning of the fish community. The study also highlighted the poor knowledge of the impacts of

  9. Key parameters of the sediment surface morphodynamics in an estuary - An assessment of model solutions

    Science.gov (United States)

    Sampath, D. M. R.; Boski, T.

    2018-05-01

    Large-scale geomorphological evolution of an estuarine system was simulated by means of a hybrid estuarine sedimentation model (HESM) applied to the Guadiana Estuary, in Southwest Iberia. The model simulates the decadal-scale morphodynamics of the system under environmental forcing, using a set of analytical solutions to simplified equations of tidal wave propagation in shallow waters, constrained by empirical knowledge of estuarine sedimentary dynamics and topography. The key controlling parameters of the model are bed friction (f), current velocity power of the erosion rate function (N), and sea-level rise rate. An assessment of sensitivity of the simulated sediment surface elevation (SSE) change to these controlling parameters was performed. The model predicted the spatial differentiation of accretion and erosion, the latter especially marked in the mudflats within mean sea level and low tide level and accretion was mainly in a subtidal channel. The average SSE change mutually depended on both the friction coefficient and power of the current velocity. Analysis of the average annual SSE change suggests that the state of intertidal and subtidal compartments of the estuarine system vary differently according to the dominant processes (erosion and accretion). As the Guadiana estuarine system shows dominant erosional behaviour in the context of sea-level rise and sediment supply reduction after the closure of the Alqueva Dam, the most plausible sets of parameter values for the Guadiana Estuary are N = 1.8 and f = 0.8f0, or N = 2 and f = f0, where f0 is the empirically estimated value. For these sets of parameter values, the relative errors in SSE change did not exceed ±20% in 73% of simulation cells in the studied area. Such a limit of accuracy can be acceptable for an idealized modelling of coastal evolution in response to uncertain sea-level rise scenarios in the context of reduced sediment supply due to flow regulation. Therefore, the idealized but cost

  10. 15 CFR 921.52 - Promotion and coordination of estuarine research.

    Science.gov (United States)

    2010-01-01

    ... 15 Commerce and Foreign Trade 3 2010-01-01 2010-01-01 false Promotion and coordination of estuarine research. 921.52 Section 921.52 Commerce and Foreign Trade Regulations Relating to Commerce and... Research Projects § 921.52 Promotion and coordination of estuarine research. (a) NOAA will promote and...

  11. Control of fouling organisms in estuarine cooling water systems by chlorine and bromine chloride

    International Nuclear Information System (INIS)

    Burton, D.T.; Margrey, S.L.

    1979-01-01

    The study described was initiated to evaluate the antifouling effectiveness of chlorine and bromine chloride in low velocity flow areas where estuarine waters are used for cooling purposes. The relative antifouling effectiveness of chlorine and bromine chloride under intermittent and continuous modes of application in low velocity flow areas was evaluated at an estuarine power plant located on the Chesapeake Bay

  12. Toxic pressure of herbicides on microalgae in Dutch estuarine and coastal waters

    NARCIS (Netherlands)

    Booij, P; Sjollema, S.B.; van der Geest, H.G.; Leonards, P.E.G.; Lamoree, M.H.; de Voogt, W.P.; Admiraal, W.; Laane, R.W.P.M.; Vethaak, A.D.

    2015-01-01

    For several decades now, there has been an increase in the sources and types of chemicals in estuarine and coastal waters as a consequence of anthropogenic activities. This has led to considerable concern about the effects of these chemicals on the marine food chain. The fact is that estuarine and

  13. BOOK REVIEW: ESTUARINE SCIENCE: A SYNTHETIC APPROACH TO RESEARCH AND PRACTICE

    Science.gov (United States)

    This book is the product of fifty leading estuarine scientists most of whom attended a workshop convened for the purpose of "put[ting] together the case for synthesis of estuarine data and to show the capabilities of synthetic methods of research" (p. 2). The editor, John E. Hob...

  14. Effects of hydrological forcing on the structure of a tropical estuarine food web

    Science.gov (United States)

    Trisha B. Atwood; Tracy N. Wiegner; Richard A. MacKenzie

    2012-01-01

    River flow can impact which sources of particulate organic matter (POM) fuel estuarine food webs. Here, we used stable carbon (C) and nitrogen (N) isotope analyses to compare how contributions of diff erent POM sources (terrestrial, estuarine, and marine) to the diets of zooplankton and juvenile fishes differed between low and high river flow conditions, as well as...

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

    Data.gov (United States)

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

  16. Transport of persistent organic pollutants by microplastics in estuarine conditions

    Science.gov (United States)

    Bakir, Adil; Rowland, Steven J.; Thompson, Richard C.

    2014-03-01

    Microplastics represent an increasing source of anthropogenic contamination in aquatic environments, where they may also act as scavengers and transporters of persistent organic pollutants. As estuaries are amongst the most productive aquatic systems, it is important to understand sorption behaviour and transport of persistent organic pollutants (POPs) by microplastics along estuarine gradients. The effects of salinity sorption equilibrium kinetics on the distribution coefficients (Kd) of phenanthrene (Phe) and 4,4‧-DDT, onto polyvinyl chloride (PVC) and onto polyethylene (PE) were therefore investigated. A salinity gradient representing freshwater, estuarine and marine conditions, with salinities corresponding to 0 (MilliQ water, 690 μS/cm), 8.8, 17.5, 26.3 and 35 was used. Salinity had no significant effect on the time required to reach equilibrium onto PVC or PE and neither did it affect desorption rates of contaminants from plastics. Although salinity had no effect on sorption capacity of Phe onto plastics, a slight decrease in sorption capacity was observed for DDT with salinity. Salinity had little effect on sorption behaviour and POP/plastic combination was shown to be a more important factor. Transport of Phe and DDT from riverine to brackish and marine waters by plastic is therefore likely to be much more dependent on the aqueous POP concentration than on salinity. The physical characteristics of the polymer and local environmental conditions (e.g. plastic density, particle residence time in estuaries) will affect the physical transport of contaminated plastics. A transport model of POPs by microplastics under estuarine conditions is proposed. Transport of Phe and DDT by PVC and PE from fresh and brackish water toward fully marine conditions was the most likely net direction for contaminant transport and followed the order: Phe-PE >> DDT-PVC = DDT-PE >> Phe-PVC.

  17. Assessment of Godavari estuarine mangrove ecosystem through trace metal studies

    Digital Repository Service at National Institute of Oceanography (India)

    Ray, A.K.; Tripathy, S.C.; Patra, S.; Sarma, V.V.

    York), pp. 265?286, 1975. 12. Ranga Rao, V., Reddy, B. S. R., Raman, A. V. & Ramana Murthy, M. V. Oceanographic features of the Bay-mangrove waterways of Coringa, East coast of India. Proc. AP Akad. Sc., 7 (2): 135-142, 2003. 13. Robertson, A. I...-Godavari estuarine mangrove ecosystem, Andhra Pradesh, India. Indian J Mar. Sc. (in press), 2004. 18. Turkian, K. K. and Wedephol, K. H. Distribution of the elements in some major units of the earth crust. Bull. Geol. Soc. Amer., 72: 175-192, 1961. 19. Twilley, R...

  18. A checklist of malacofauna of the Vellar Estuarine Mangroves, India

    Directory of Open Access Journals (Sweden)

    K. Kesavan

    2009-07-01

    Full Text Available A survey conducted to know the diversity of malacofauna in Vellar estuarine mangroves (southeast coast of India. In this study, 13 species of molluscs (10 species of gastropods - Melampus ceylonicus, Cerithidea cingulata, Cassidula nucleus, Pythia plicata, Neritina (Dostia violacea, Littorina scabra, Littorina melanostoma, Ellobium aurisjudae, C. obtusa T. telescopium and Assiminea nitida and 3 species of bivalves - Perna viridis, Crassostrea madrasensis and Modiolus metcalfei were recorded. M. pulchella, C. obtusa, L. scabra and N. violacea were found arboreal. T. telescopium, C. cingulata and E. aurisjudae were found crawling on the intertidal mud.

  19. Particle-borne radionuclides as tracers for sediment in the Susquehanna River and Chesapeake Bay

    Energy Technology Data Exchange (ETDEWEB)

    Donoghue, J F [Florida State Univ., Tallahassee, FL (USA). Dept. of Geology; Bricker, O P [Geological Survey, Reston, VA (USA). Water Resources Div.; Olsen, C R [Oak Ridge National Lab., TN (USA)

    1989-10-01

    The Chesapeake Bay receives nearly 1,000,000 tonnes of sediment annually from its major tributary, the Susquehanna River. The pattern of deposition of this sediment affects the lifetime of the estuarine resource and the fate of any sediment-borne contaminants. Previous estimates of the extent to which Susquehanna River sediment is transported down the Chesapeake have differed considerably. By use of reactor-generated radionuclides adsorbed on the river sediment, a sediment budget has been compiled for the upper Chesapeake Bay and the reservoirs on the lower Susquehanna. Reservoirs impound nearly 1,400,000 tonnes of sediment annually behind the power dams on the lower Susquehanna River. Without the dams, sediment delivery to the upper bay would more than double. The uppermost Chesapeake Bay, within and above the turbidity maximum, retains virtually all of the fluvial sediment delivered to it. The result is an annual sedimentation rate of approximately 3 mm yr{sup -1} in the upper bay, an infilling rate that is nearly equal to the regional rate of sea level rise. (author).

  20. Particle-borne radionuclides as tracers for sediment in the Susquehanna River and Chesapeake Bay

    International Nuclear Information System (INIS)

    Donoghue, J.F.

    1989-01-01

    The Chesapeake Bay receives nearly 1,000,000 tonnes of sediment annually from its major tributary, the Susquehanna River. The pattern of deposition of this sediment affects the lifetime of the estuarine resource and the fate of any sediment-borne contaminants. Previous estimates of the extent to which Susquehanna River sediment is transported down the Chesapeake have differed considerably. By use of reactor-generated radionuclides adsorbed on the river sediment, a sediment budget has been compiled for the upper Chesapeake Bay and the reservoirs on the lower Susquehanna. Reservoirs impound nearly 1,400,000 tonnes of sediment annually behind the power dams on the lower Susquehanna River. Without the dams, sediment delivery to the upper bay would more than double. The uppermost Chesapeake Bay, within and above the turbidity maximum, retains virtually all of the fluvial sediment delivered to it. The result is an annual sedimentation rate of approximately 3 mm yr -1 in the upper bay, an infilling rate that is nearly equal to the regional rate of sea level rise. (author)

  1. Tracing organophosphorus and brominated flame retardants and plasticizers in an estuarine food web.

    Science.gov (United States)

    Brandsma, Sicco H; Leonards, Pim E G; Leslie, Heather A; de Boer, Jacob

    2015-02-01

    Nine organophosphorus flame retardants (PFRs) were detected in a pelagic and benthic food web of the Western Scheldt estuary, The Netherlands. Concentrations of several PFRs were an order of magnitude higher than those of the brominated flame retardants (BFRs). However, the detection frequency of the PFRs (6-56%) was lower than that of the BFRs (50-97%). Tris(2-butoxyethyl) phosphate (TBOEP), tris(isobutyl) phosphate (TIBP) and tris(2-chloroisopropyl) phosphate (TCIPP) were the dominant PFRs in sediment with median concentrations of 7.0, 8.1 and 1.8 ng/g dry weight (dw), respectively. PFR levels in the suspended particular matter (SPM) were 2-12 times higher than that in sediment. TBOEP, TCIPP, TIBP, tris(2-chloroethyl) phosphate (TCEP) and tris(phenyl) phosphate (TPHP) were found in organisms higher in the estuarine food web. The highest PFR concentrations in the benthic food web were found in sculpin, goby and lugworm with median concentrations of 17, 7.4, 4.6 and 2.0 ng/g wet weight (ww) for TBOEP, TIBP, TCIPP and TPHP, respectively. Comparable levels were observed in the pelagic food web, BDE209 was the predominant PBDE in sediment and SPM with median concentrations up to 9.7 and 385 ng/g dw, respectively. BDE47 was predominant in the biotic compartment of the food web with highest median levels observed in sculpin and common tern eggs of 79 ng/g lipid weight (lw) (2.5 ng/g ww) and 80 ng/g lw (11 ng/g ww), respectively. Trophic magnification was observed for all PBDEs with the exception of BDE209. Indications of trophic magnification of PFRs were observed in the benthic food web for TBOEP, TCIPP and TCEP with tentative trophic magnification factors of 3.5, 2.2 and 2.6, respectively (pwebs. The relative high PFR levels in several fish species suggest high emissions and substantial exposure of organisms to PFRs in the Western Scheldt. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Source identification, geochemical normalization and influence factors of heavy metals in Yangtze River Estuary sediment.

    Science.gov (United States)

    Sun, Xueshi; Fan, Dejiang; Liu, Ming; Tian, Yuan; Pang, Yue; Liao, Huijie

    2018-06-18

    Sediment samples, including 40 surface samples and 12 sediment cores, were collected from 52 stations of the Yangtze River Estuary (YRE) in 2015 and 2016. The 95% linear prediction intervals (LPI) and principal components analysis (PCA), were conducted to evaluate the metal sources and grain-size effect (GSE). The in situ physico-chemical properties of pH, Eh, DO, salinity, temperature and turbidity were combined to elucidate the relationships between environmental factors and the fate of heavy metals in the river-estuary-shelf system. This study indicates a decreasing trend of metals in sediments from the estuary towards the adjacent shelf and the river channel and that Zn, Cu and Cr are mainly derived from natural processes throughout the catchment, whereas Pb appears to have anthropogenic inputs via atmospheric deposition. Furthermore, considering the best fit regression lines between the concentrations of Al and heavy metals as well as the deficiencies of the conventional C elements /C Al method, we introduce an approach (Al-SN: Al-scope normalization) that can eliminate the GSE on heavy metals and be applied to other estuaries. After Al-scope normalization, the relatively constant levels of Zn, Cu and Cr that remain in sediments from the river channel to the estuary and shelf confirmed that the variation of grain size in sediments almost entirely explained the distribution patterns of sediment toxicity in the YRE, while the enrichment of Pb in estuarine sediments could be attributed to its chemical species and physico-chemical properties. The results further suggest that the relationship between grain size and spatial behavior of sediment pollutants should be given priority over the contamination assessment and provenance discrimination in estuarine or similar environments with complex sediment compositions. Copyright © 2018 Elsevier Ltd. All rights reserved.

  3. New climatic targets against global warming: will the maximum 2 °C temperature rise affect estuarine benthic communities?

    Science.gov (United States)

    Crespo, Daniel; Grilo, Tiago Fernandes; Baptista, Joana; Coelho, João Pedro; Lillebø, Ana Isabel; Cássio, Fernanda; Fernandes, Isabel; Pascoal, Cláudia; Pardal, Miguel Ângelo; Dolbeth, Marina

    2017-06-20

    The Paris Agreement signed by 195 countries in 2015 sets out a global action plan to avoid dangerous climate change by limiting global warming to remain below 2 °C. Under that premise, in situ experiments were run to test the effects of 2 °C temperature increase on the benthic communities in a seagrass bed and adjacent bare sediment, from a temperate European estuary. Temperature was artificially increased in situ and diversity and ecosystem functioning components measured after 10 and 30 days. Despite some warmness effects on the analysed components, significant impacts were not verified on macro and microfauna structure, bioturbation or in the fluxes of nutrients. The effect of site/habitat seemed more important than the effects of the warmness, with the seagrass habitat providing more homogenous results and being less impacted by warmness than the adjacent bare sediment. The results reinforce that most ecological responses to global changes are context dependent and that ecosystem stability depends not only on biological diversity but also on the availability of different habitats and niches, highlighting the role of coastal wetlands. In the context of the Paris Agreement it seems that estuarine benthic ecosystems will be able to cope if global warming remains below 2 °C.

  4. Estuarine retention of larvae of the crab Rhithropanopeus harrisii

    Science.gov (United States)

    Cronin, Thomas W.

    1982-08-01

    Larvae of estuarine organisms continually face possible export from the parent estuary. Retention of larvae of the estuarine crab Rhithropanopeus harrisii was investigated in the upper Newport River estuary, North Carolina. All of the developmental stages occurred in the same area of the estuary with similar horizontal distributions, and the concentrations of intermediate and late stages were not greatly reduced from those of the first larval stage. This was strong evidence for the continuous retention of larvae in the upper estuary. To determine mechanisms by which retention might be effected, field studies of the vertical distributions and migrations of these larvae were made. The four zoeal stages had similar but complex vertical migration patterns, which varied from study to study. These migrations centered on the depth of no net flow, reducing longitudinal transport during development. Cross-spectral analysis of the larval migrations and the environmental cycles of light, salinity and current speed revealed that each of these external cycles affected larval depth. Megalopae of R. harrisii also migrated vertically, but they were present in much lower concentrations than the zoeal stages, an indication of a change to benthic existence in this final larval form.

  5. Influence of estuarine processes on spatiotemporal variation in bioavailable selenium

    Science.gov (United States)

    Stewart, Robin; Luoma, Samuel N.; Elrick, Kent A.; Carter, James L.; van der Wegen, Mick

    2013-01-01

    Dynamic processes (physical, chemical and biological) challenge our ability to quantify and manage the ecological risk of chemical contaminants in estuarine environments. Selenium (Se) bioavailability (defined by bioaccumulation), stable isotopes and molar carbon-tonitrogen ratios in the benthic clam Potamocorbula amurensis, an important food source for predators, were determined monthly for 17 yr in northern San Francisco Bay. Se concentrations in the clams ranged from a low of 2 to a high of 22 μg g-1 over space and time. Little of that variability was stochastic, however. Statistical analyses and preliminary hydrodynamic modeling showed that a constant mid-estuarine input of Se, which was dispersed up- and down-estuary by tidal currents, explained the general spatial patterns in accumulated Se among stations. Regression of Se bioavailability against river inflows suggested that processes driven by inflows were the primary driver of seasonal variability. River inflow also appeared to explain interannual variability but within the range of Se enrichment established at each station by source inputs. Evaluation of risks from Se contamination in estuaries requires the consideration of spatial and temporal variability on multiple scales and of the processes that drive that variability.

  6. Isolation of heterotrophic diazotrophic bacteria from estuarine surface waters.

    Science.gov (United States)

    Farnelid, Hanna; Harder, Jens; Bentzon-Tilia, Mikkel; Riemann, Lasse

    2014-10-01

    The wide distribution of diverse nitrogenase (nifH) genes affiliated with those of heterotrophic bacteria in marine and estuarine waters indicates ubiquity and an ecologically relevant role for heterotrophic N2 -fixers (diazotrophs) in aquatic nitrogen (N) cycling. However, the lack of cultivated representatives currently precludes an evaluation of their N2 -fixing capacity. In this study, microoxic or anoxic N-free media were inoculated with estuarine Baltic Sea surface water to select for N2 -fixers. After visible growth and isolation of single colonies on oxic plates or in anoxic agar tubes, nifH gene amplicons were obtained from 64 strains and nitrogenase activity, applying the acetylene reduction assay, was confirmed for 40 strains. Two strains, one Gammaproteobacterium affiliated with Pseudomonas and one Alphaproteobacterium affiliated with Rhodopseudomonas were shown to represent established members of the indigenous diazotrophic community in the Baltic Sea, with abundances of up to 7.9 × 10(4) and 4.7 × 10(4)  nifH copies l(-1) respectively. This study reports media for successful isolation of heterotrophic diazotrophs. The applied methodology and the obtained strains will facilitate future identification of factors controlling heterotrophic diazotrophic activity in aquatic environments, which is a prerequisite for understanding and evaluating their ecology and contribution to N cycling at local and regional scales. © 2013 Society for Applied Microbiology and John Wiley & Sons Ltd.

  7. Hourly and daily variation of sediment redox potential in tidal wetland sediments

    Science.gov (United States)

    Catallo, W. James

    1999-01-01

    Variation of electrochemical oxidation-reduction (redox) potential was examined in surface salt march sediments under conditions of flooding and tidal simulation in mesocosms and field sites. Time series were generated of redox potential measured in sediment profiles at 2-10 cm depth using combination Pt-Ag/AgCl (ORP) electrodes. Redox potential data were acquired at rapid rates (1-55 samples/h) over extended periods (3-104 days) along with similar times series of temperature (water, air, soil) and pH. It was found that redox potential vaired as a result of water level changes and was unrelated to diurnal changes in temperature or pH, the latter of which changed by 370 mV redox potential decrease in under 48 hours). Attenuatoin of microbial activity by [gamma] y-radiation and toxic chemicals elimintated this response. In tidal salt marsh mesocosms where the sediment-plant assemblages were exposed to a simulated diurnal tide, redox potenial oscillations of 40-300 mV amplitude were recoded that has the same periodicity as the flood-drain cycle. Periodic redoc potential time series were observed repeatedly in sediments receiving tidal pulsing but not in those sediments exposed to static hydrological conditions. Data collected over 12 days from a coastal marsh site experiencing diurnal tides showed similar fluctuations in redox potential. Data from the experimentents indicated that (a) redox potential can be a dynamic, nonlinear variable in coastal and estuarine wetland sediments over hourly and daily scales, and the designs of biogeochemical experiments should reflect this, (b) redox potential can change rapidly and signigicantly in coastal wetland sediments in response of flooding and draining, (c) microbial community processes are primarily determinants of the time course of redox potential in wetland sediments, and elimination of inhibition of microbial activity (e.g. by pollutants) can significantly alter that behavior, and (d) fast redox potential dynamics appear

  8. Biodynamic modelling of the bioaccumulation of trace metals (Ag, As and Zn) by an infaunal estuarine invertebrate, the clam Scrobicularia plana

    International Nuclear Information System (INIS)

    Kalman, J.; Smith, B.D.; Bury, N.R.; Rainbow, P.S.

    2014-01-01

    Highlights: • Biodynamic modelling is used to predict accumulation of Ag, As and Zn in S. plana. • Dissolved and sediment-associated metals contribute to total metal bioaccumulation. • Relative importance varies with water and sediment concentrations and geochemistries. - Abstract: Biodynamic modelling was used to investigate the uptake and accumulation of three trace metals (Ag, As, Zn) by the deposit feeding estuarine bivalve mollusc Scrobicularia plana. Radioactive labelling techniques were used to quantify the rates of trace metal uptake (and subsequent elimination) from water and sediment diet. The uptake rate constant from solution (±SE) was greatest for Ag (3.954 ± 0.375 l g −1 d −1 ) followed by As (0.807 ± 0.129 l g −1 d −1 ) and Zn (0.103 ± 0.016 l g −1 d −1 ). Assimilation efficiencies from ingested sediment were 40.2 ± 1.3% (Ag), 31.7 ± 1.0% (Zn) and 25.3 ± 0.9% (As). Efflux rate constants after exposure to metals in the solution or sediment fell in the range of 0.014–0.060 d −1 . By incorporating these physiological parameters into biodynamic models, our results showed that dissolved metal is the predominant source of accumulated Ag, As and Zn in S. plana, accounting for 66–99%, 50–97% and 52–98% of total accumulation of Ag, As and Zn, respectively, under different field exposure conditions. In general, model-predicted steady state concentrations of Ag, As and Zn matched well with those observed in clams collected in SW England estuaries. Our findings highlight the potential of biodynamic modelling to predict Ag, As and Zn accumulation in S. plana, taking into account specific dissolved and sediment concentrations of the metals at a particular field site, together with local water and sediment geochemistries

  9. Chemistry of marine sediments

    International Nuclear Information System (INIS)

    Yen, T.F.

    1977-01-01

    Some topics considered are as follows: characterization of sediments in the vicinity of offshore petroleum production; thermal alteration experiments on organic matter in recent marine sediments as a model for petroleum genesis; composition of polluted bottom sediments in Great Lakes harbors; distribution of heavy metals in sediment fractions; recent deposition of lead off the coast of southern California; release of trace constituents from sediments resuspended during dredging operations; and migration of chemical constituents in sediment-seawater interfaces

  10. Mapping Sea Level Rise Behavior in an Estuarine Delta System: A Case Study along the Shanghai Coast

    Directory of Open Access Journals (Sweden)

    H.Q. Cheng

    2018-02-01

    Full Text Available Sea level rise (SLR is a major projected threat of climate change that is expected to affect developing coastal cities located in estuarine delta regions. Shanghai is one such city, being located in the Yangtze River Delta (YRD. It is difficult, however, for decision-makers to implement adaptation due to the uncertain causes, magnitudes, and timings of SLR behaviors. This paper attempts to map the causes and magnitudes of SLR behaviors on a decadal scale. We analyze the tidal level records from 11 tidal gauge stations and the corresponding bathymetry measurements around these stations since 1921. We identify three new SLR behaviors along the Shanghai coast due to anthropogenic geomorphologic changes (AGCs, besides the well-known eustatic sea level rise (ESLR, tectonic subsidence (TS, and urban land subsidence (ULS. The first new behavior is regional sea level rise (RSLR, which occurs as a result of land reclamation and deep waterway regulation. The second is regional sea level fall (RSLF, which occurs because the channel bed is eroded due to sediment supply decline in the river catchment. The last SLR behavior is local tidal datum rise (LTDR. Thus, we project that the magnitude of SLR for the Shanghai coast ranges from 10 cm to 16 cm from 2011 to 2030. Clarifying SLR behaviors is important to aid local decision-makers in planning structural and non-structural measures to combat escalating flood damage costs in an estuarine delta system; this field is full of future challenges. Keywords: Sea level rise behavior, Anthropogenic geomorphologic change, Local tidal datum, Flood management, Adaptation

  11. Ability of salt marsh plants for TBT remediation in sediments.

    Science.gov (United States)

    Carvalho, Pedro N; Basto, M Clara P; Silva, Manuela F G M; Machado, Ana; Bordalo, A A; Vasconcelos, M Teresa S D

    2010-07-01

    The capability of Halimione portulacoides, Spartina maritima, and Sarcocornia fruticosa (halophytes very commonly found in salt marshes from Mediterranean areas) for enhancing remediation of tributyltin (TBT) from estuarine sediments was investigated, using different experimental conditions. The influence of H. portulacoides on degradation of the butyltin compounds was assessed in two different ways: (1) a 9-month ex situ study carried out in a site of Sado River estuary, center of Portugal, which used polluted sediments collected at other nonvegetated site from the same estuary; and (2) a 12-month laboratorial study, using both plant and sediment collected at a relatively clean site of Cávado River estuary, north of Portugal, the sediment being doped with TBT, DBT, and MBT at the beginning of the experiment. The role of both S. fruticosa and S. maritima on TBT remediation in sediments was evaluated in situ, in salt marshes from Marim channel of Ria Formosa lagoon, south of Portugal, which has large areas colonized by each one of these two plants. For estimation of microbial abundance, total cell counts of sediment samples were enumerated by the DAPI direct count method. Butyltin analyses in sediment were performed using a method previously validated, which consisted of headspace solid-phase micro-extraction combined with gas chromatography-mass spectrometry after in situ ethylation (with tetraethylborate). Sediments colonized both ex situ and at lab by H. portulacoides displayed TBT levels about 30% lower than those for nonvegetated sediments with identical initial composition, after 9-12 months of plant exposure. In addition, H. portulacoides showed to be able of stimulating bacterial growth in the plant rhizosphere, which probably included degraders of TBT. In the in situ study, which compared the levels of TBT, DBT, and MBT in nonvegetated sediment and in sediments colonized by either S. maritima or S. fruticosa from the same area, TBT and DBT were only

  12. As Clear as Mud? Determining the Diversity and Prevalence of Prophages in the Draft Genomes of Estuarine Isolates of Clostridium difficile.

    Science.gov (United States)

    Hargreaves, Katherine R; Otieno, James R; Thanki, Anisha; Blades, Matthew J; Millard, Andrew D; Browne, Hilary P; Lawley, Trevor D; Clokie, Martha R J

    2015-05-27

    The bacterium Clostridium difficile is a significant cause of nosocomial infections worldwide. The pathogenic success of this organism can be attributed to its flexible genome which is characterized by the exchange of mobile genetic elements, and by ongoing genome evolution. Despite its pathogenic status, C. difficile can also be carried asymptomatically, and has been isolated from natural environments such as water and sediments where multiple strain types (ribotypes) are found in close proximity. These include ribotypes which are associated with disease, as well as those that are less commonly isolated from patients. Little is known about the genomic content of strains in such reservoirs in the natural environment. In this study, draft genomes have been generated for 13 C. difficile isolates from estuarine sediments including clinically relevant and environmental associated types. To identify the genetic diversity within this strain collection, whole-genome comparisons were performed using the assemblies. The strains are highly genetically diverse with regards to the C. difficile "mobilome," which includes transposons and prophage elements. We identified a novel transposon-like element in two R078 isolates. Multiple, related and unrelated, prophages were detected in isolates across ribotype groups, including two novel prophage elements and those related to the transducing phage φC2. The susceptibility of these isolates to lytic phage infection was tested using a panel of characterized phages found from the same locality. In conclusion, estuarine sediments are a source of genetically diverse C. difficile strains with a complex network of prophages, which could contribute to the emergence of new strains in clinics. © The Author(s) 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  13. Coordination and standardization of federal sedimentation activities

    Science.gov (United States)

    Glysson, G. Douglas; Gray, John R.

    1997-01-01

    In August 1964, the Bureau of the Budget issued Circular A-67 to set forth guidelines for the coordination of water-data acquisition activities throughout the Federal government. The U.S. Department of the Interior was assigned the task of implementing Circular A-67, which in turn redelegated this responsibility to the U.S. Geological Survey (USGS). Delegation of the lead responsibility for water-data coordination to the USGS occurred because of its historical role as the primary agency for water-data acquisition in the United States. To provide overall leadership for implementing the provisions of Circular A-67, the USGS established the Office of Water Data Coordination in the Water Resources Division (WRD). In addition, regional and district offices of the WRD were delegated responsibility for coordinating water data within their geographic areas of responsibility. On December 10, 1991, the Office of Management and Budget issued OMB Number Memorandum M-92-01, which expands the USGS's coordination role to encompass all water information. This includes data critical to water resources in the following categories: - surface- and ground-water quality and quantity,

  14. Effects of dredged sediment disposal on the coastal marine macrobenthic assemblage in Southern Brazil

    Directory of Open Access Journals (Sweden)

    L. G. Angonesi

    Full Text Available The aim of this study was to evaluate the deposition impact of dredged material from Patos lagoon estuary on a benthic macroinvertebrate assemblage structure in an adjacent coastal marine area. Nine sampling stations were chosen at random in the disposal area, and nine others in the same way in an adjacent control area. Samples were collected at a 19 m depth before sediment disposal (11 July 2000, during dredging and disposal operations (25 Oct. 2000, and three months thereafter (24 Aug. 2001. Statistical analysis indicated that sampling periods presented similar characteristics in both the control and disposal sites. Disposal of dredged sediment from Patos lagoon had no detectable detrimental effects upon macrobenthic faunal assemblage at the dumping site. This result is attributed both to adaptation of resident biota to dynamic sedimentary conditions and to the fine estuarine sediment dredged, the dispersion of which in the water column might have minimized sediment deposition and consequent damage to the benthic fauna.

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

    Directory of Open Access Journals (Sweden)

    P. A. Jenkins

    2002-01-01

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

  16. Ecoengineering with Ecohydrology: Successes and failures in estuarine restoration

    Science.gov (United States)

    Elliott, Michael; Mander, Lucas; Mazik, Krysia; Simenstad, Charles; Valesini, Fiona; Whitfield, Alan; Wolanski, Eric

    2016-07-01

    Ecological Engineering (or Ecoengineering) is increasingly used in estuaries to re-create and restore ecosystems degraded by human activities, including reduced water flow or land poldered for agricultural use. Here we focus on ecosystem recolonization by the biota and their functioning and we separate Type A Ecoengineering where the physico-chemical structure is modified on the basis that ecological structure and functioning will then follow, and Type B Ecoengineering where the biota are engineered directly such as through restocking or replanting. Modifying the physical system to create and restore natural processes and habitats relies on successfully applying Ecohydrology, where suitable physical conditions, especially hydrography and sedimentology, are created to recover estuarine ecology by natural or human-mediated colonisation of primary producers and consumers, or habitat creation. This successional process then allows wading birds and fish to reoccupy the rehabilitated areas, thus restoring the natural food web and recreating nursery areas for aquatic biota. We describe Ecohydrology principles applied during Ecoengineering restoration projects in Europe, Australia, Asia, South Africa and North America. These show some successful and sustainable approaches but also others that were less than successful and not sustainable despite the best of intentions (and which may even have harmed the ecology). Some schemes may be 'good for the ecologists', as conservationists consider it successful that at least some habitat was created, albeit in the short-term, but arguably did little for the overall ecology of the area in space or time. We indicate the trade-offs between the short- and long-term value of restored and created ecosystems, the success at developing natural structure and functioning in disturbed estuaries, the role of this in estuarine and wetland management, and the costs and benefits of Ecoengineering to the socio-ecological system. These global case

  17. Superstorm Sandy-related Morphologic and Sedimentologic Changes in an Estuarine System: Barnegat Bay-Little Egg Harbor Estuary, New Jersey

    Science.gov (United States)

    Miselis, J. L.; Ganju, N. K.; Navoy, A.; Nicholson, R.; Andrews, B.

    2013-12-01

    Despite the well-recognized ecological importance of back-barrier estuaries, the role of storms in their geomorphic evolution is poorly understood. Moreover, the focus of storm impact assessments is often the ocean shorelines of barrier islands rather than the exchange of sediment from barrier to estuary. In order to better understand and ultimately predict short-term morphologic and sedimentologic changes in coastal systems, a comprehensive research approach is required but is often difficult to achieve given the diversity of data required. An opportunity to use such an approach in assessing the storm-response of a barrier-estuary system occurred when Superstorm Sandy made landfall near Atlantic City, New Jersey on 29 October 2012. Since 2011, the US Geological Survey has been investigating water circulation and water-quality degradation in Barnegat Bay-Little Egg Harbor (BBLEH) Estuary, the southern end of which is approximately 25 kilometers north of the landfall location. This effort includes shallow-water geophysical surveys to map the bathymetry and sediment distribution within BBLEH, airborne topo-bathymetric lidar surveys for mapping the shallow shoals that border the estuary, and sediment sampling, all of which have provided a recent picture of the pre-storm estuarine geomorphology. We combined these pre-storm data with similar post-storm data from the estuary and pre- and post-storm topographic data from the ocean shoreline of the barrier island to begin to understand the response of the barrier-estuary system. Breaches in the barrier island resulted in water exchange between the estuary and the ocean, briefly reducing residence times in the northern part of the estuary until the breaches were closed. Few morphologic changes in water depths greater than 1.5 m were noted. However, morphologic changes observed in shallower depths along the eastern shoreline of the estuary are likely related to overwash processes. In general, surficial estuarine sediments

  18. Hindcasting of decadal‐timescale estuarine bathymetric change with a tidal‐timescale model

    Science.gov (United States)

    Ganju, Neil K.; Schoellhamer, David H.; Jaffe, Bruce E.

    2009-01-01

    Hindcasting decadal-timescale bathymetric change in estuaries is prone to error due to limited data for initial conditions, boundary forcing, and calibration; computational limitations further hinder efforts. We developed and calibrated a tidal-timescale model to bathymetric change in Suisun Bay, California, over the 1867–1887 period. A general, multiple-timescale calibration ensured robustness over all timescales; two input reduction methods, the morphological hydrograph and the morphological acceleration factor, were applied at the decadal timescale. The model was calibrated to net bathymetric change in the entire basin; average error for bathymetric change over individual depth ranges was 37%. On a model cell-by-cell basis, performance for spatial amplitude correlation was poor over the majority of the domain, though spatial phase correlation was better, with 61% of the domain correctly indicated as erosional or depositional. Poor agreement was likely caused by the specification of initial bed composition, which was unknown during the 1867–1887 period. Cross-sectional bathymetric change between channels and flats, driven primarily by wind wave resuspension, was modeled with higher skill than longitudinal change, which is driven in part by gravitational circulation. The accelerated response of depth may have prevented gravitational circulation from being represented properly. As performance criteria became more stringent in a spatial sense, the error of the model increased. While these methods are useful for estimating basin-scale sedimentation changes, they may not be suitable for predicting specific locations of erosion or deposition. They do, however, provide a foundation for realistic estuarine geomorphic modeling applications.

  19. Environmental and Microbial Features Affecting Denitrification and Anammox Hotspots in an Estuarine Ecosystem

    Science.gov (United States)

    Lisa, J.; Song, B.; Lefcheck, J. S.; Tobias, C. R.

    2016-02-01

    Biogeochemical hotspots are characterized as a few sites that exhibit extremely high reaction rates relative to surrounding area, and often account for a high percentage of the overall reaction rates in an ecosystem. Criteria for quantitatively identifying these sites have not been well established. Further, the underlying mechanisms of hotspots have been described in terms of environmental conditions, with little attention paid to the microbial community. The objectives of this study were to establish quantitative criteria to identify denitrification and anammox hotspots, and determine the underlying microbial and environmental factors responsible for elevated N2 production. We used 15N isotope pairing incubation experiments to measure denitrification and anammox rates in the New River Estuary, NC. Quantitative PCR assays of nitrous oxide reductase (nosZ Clades I and II) and hydrazine oxidoreductase (hzo) genes were conducted to estimate denitrifier and anammox abundance. Structural Equation Modeling (SEM) was used to elucidate complex causal relationships between environmental and biological variables. Denitrification hotspots, quantitatively defined as statistical outliers, accounted for 35.6% total denitrification while comprising only 7.3% of the sites. Anammox hotspots,10.6% of the sites, accounted for 60.9% of total anammox. SEM revealed increased sediment organics at lower salinities supported higher functional gene abundance, which in turn resulted in higher N2 production. Surprisingly, denitrification rates were significantly and positively correlated with nosZ Clade II gene abundance, after accounting for the non-significant contributions of the naturally more abundant nosZ Clade I, and other environmental covariates. This is the first time that a quantitative definition of biogeochemical hotspots was put forth and used to determine the importance of anammox and denitrification hotspots in estuarine nitrogen removal capacity. Despite the low area

  20. A research program in determination of heavy metals in sediments and benthic species in relation to nuclear power plant operation

    Science.gov (United States)

    Phelps, H. L.

    1984-01-01

    Heavy metals in the estuarine environment can be toxic to fish and shellfish early life history stages and concentrations build up to levels of concern in marketable shellfish. The present survey was begun just before startup in 1974 of the 1900 megawatt Calvert Cliffs Nuclear Power Plant on the Chesapeake Bay in order to assess and understand factors relating to heavy metal accumulation in estuarine biota. Oysters were collected in large numbers at test and reference sites in June 1974 to 77 and individually analyzed for copper and zinc. Oyster copper and zinc concentrations were correlated with salinity read at time of collection. The relationship of oyster age to metal concentration was examined with two sets of oysters of known age and genetic origin (laboratory spawned). Copper sorption by typical mid Bay sediments, and field studies on cadmium concentrations in sediments were examined.

  1. A review of nickel toxicity to marine and estuarine tropical biota with particular reference to the South East Asian and Melanesian region.

    Science.gov (United States)

    Gissi, Francesca; Stauber, Jennifer L; Binet, Monique T; Golding, Lisa A; Adams, Merrin S; Schlekat, Christian E; Garman, Emily R; Jolley, Dianne F

    2016-11-01

    The South East Asian Melanesian (SEAM) region contains the world's largest deposits of nickel lateritic ores. Environmental impacts may occur if mining operations are not adequately managed. Effects data for tropical ecosystems are required to assess risks of contaminant exposure and to derive water quality guidelines (WQG) to manage these risks. Currently, risk assessment tools and WQGs for the tropics are limited due to the sparse research on how contaminants impact tropical biota. As part of a larger project to develop appropriate risk assessment tools to ensure sustainable nickel production in SEAM, nickel effects data were required. The aim of this review was to compile data on the effects of nickel on tropical marine, estuarine, pelagic and benthic species, with a particular focus on SEAM. There were limited high quality chronic nickel toxicity data for tropical marine species, and even fewer for those relevant to SEAM. Of the data available, the most sensitive SEAM species to nickel were a sea urchin, copepod and anemone. There is a significant lack of high quality chronic data for several ecologically important taxonomic groups including cnidarians, molluscs, crustaceans, echinoderms, macroalgae and fish. No high quality chronic nickel toxicity data were available for estuarine waters or marine and estuarine sediments. The very sparse toxicity data for tropical species limits our ability to conduct robust ecological risk assessment and may require additional data generation or read-across from similar species in other databases (e.g. temperate) to fill data gaps. Recommendations on testing priorities to fill these data gaps are presented. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Holocene Evolution and Sediment Provenance of Horn Island, Mississippi, USA

    Science.gov (United States)

    Schulze, N.; Wallace, D. J.; Miner, M. D.

    2017-12-01

    As one of the most stable islands in the Mississippi-Alabama barrier island chain, Horn Island provides critical habitat, plays an important role in regulating estuarine conditions in the Mississippi Sound, and helps to attenuate wave energy and storm surge for the mainland. The provenance of sediments comprising Horn Island is largely unknown and has implications for mode of island genesis and evolution. The existing literature proposes that island chain formation was initiated by bar emergence from a subaqueous spit that grew laterally westward from Dauphin Island in the east. Decelerating sea level rise 4,000 to 5,000 years ago facilitated island formation. This proposed mode of formation is supported by a lone radiocarbon date from lagoonal sediments below Horn Island, suggesting the system formed after 4,615 ± 215 years BP. Rivers supplying suspended sediment include the Mississippi, Pascagoula, Mobile and Apalachicola, but the variable nature of their paths and sediment supply means that Horn Island has received differing amounts of sediment from these proximal rivers throughout the Holocene. To analyze the stratigraphy and sediment characteristics of Horn Island, we will utilize 24 vibracores (up to 6 meters in length) from offshore Horn Island that were obtained by the United States Geological Survey (USGS) and 9 onshore drill cores (up to 28 meters in length) from the Mississippi Department of Environmental Quality. High-resolution LiDAR data collected by the National Oceanic and Atmospheric Administration in 2010 will be used to describe modern geomorphic barrier environments. We will employ down-core x-ray diffraction and x-ray fluorescence analyses to identify mineralogical and chemical signatures that potentially correspond to unique signatures of the fluvial sources of proximal rivers. New radiocarbon ages will be used to constrain the timing of island formation and alterations in sediment supply. High-resolution shallow geophysical data will provide

  3. Characterisation of estuarine intertidal macroalgae by laser-induced fluorescence

    DEFF Research Database (Denmark)

    Gameiro, Carla; Utkin, Andrei B.; Sousa Dias Cartaxana, Paulo Jorge

    2015-01-01

    The article reports the application of laser-induced fluorescence (LIF) for the assessment of macroalgae communities of estuarine intertidal areas. The method was applied for the characterisation of fifteen intertidal macroalgae species of the Tagus estuary, Portugal, and adjacent coastal area...... spectra were determined by differences in the main fluorescing pigments: phycoerythrin, phycocyanin and chlorophyll a (Chl a). In the green and brown macroalgae groups, the relative significance of the two emission maxima seems to be related to the thickness of the photosynthetic layer. In thick...... macroalgae, like Codium tomentosum or Fucus vesiculosus, the contribution of the far-red emission fluorescence peak was more significant, most probably due to re-absorption of the emitted red Chl a fluorescence within the dense photosynthetic layer. Similarly, an increase in the number of layers of the thin...

  4. Resting eggs in free living marine and estuarine copepods

    DEFF Research Database (Denmark)

    Holm, Mark Wejlemann; Kiørboe, Thomas; Brun, Philipp Georg

    2018-01-01

    Marine free living copepods can survive harsh periods and cope with seasonal fluctuations in environmental conditions using resting eggs (embryonic dormancy). Laboratory experiments show that temperature is the common driver for resting egg production. Hence, we hypothesize (i) that seasonal...... temperature variation, rather than variation in food abundance is the main driver for the occurrence of the resting eggs strategy in marine and estuarine copepod species; and (ii) that the thermal boundaries of the distribution determine where resting eggs are produced and whether they are produced to cope...... with warm or cold periods. We compile literature information on the occurrence of resting egg production and relate this to spatio-temporal patterns in sea surface temperature and chlorophyll a concentration obtained from satellite observations. We find that the production of resting eggs has been reported...

  5. The Aquapelago and the Estuarine City: Reflections on Manhattan

    Directory of Open Access Journals (Sweden)

    Philip Hayward

    2015-12-01

    Full Text Available Over the last decade there have been a number of attempts to both imagine Manhattan’s pre-colonial past and to envisage new ways in which the metropolitan island (and the greater New York area might more productively relate to its location within a major estuarine environment. Rising sea levels associated with global warming have given a particular focus, not to say sense of urgency, to this enterprise. This essay reviews several of the aforementioned projects and discusses their conceptual parameters with reference to recent debates in Island Studies concerning the concept of the aquapelago. Consideration is given to aspects of the cultural imagination of place and conceptions of the integration of human/urban and natural ecosystems. Drawing on these discussions, the essay outlines the manner in which established analyses of aquapelagic assemblages can be expanded to embrace metropolitan island environments.

  6. Toxicity of oils and petroleum hydrocarbons to estuarine crustaceans

    Energy Technology Data Exchange (ETDEWEB)

    Tatem, H.E. (Army Engineer Waterways Experiment Station, Vicksburg, MS); Cox, B.A.; Anderson, J.W.

    1978-04-01

    Bioassay experiments with various life stages of three estuarine shrimp and soluble petroleum hydrocarbons (PH) revealed residual Bunker C oil and refined No. 2 fuel oil to be more toxic than two crude oils tested. Larvae of Palaemonetes pugio were slightly more sensitive to the PH than adults, while young penaeid shrimp were shown to be more resistant than older, larger individuals. Shrimp exposed to PH in conjunction with temperature and salinity changes were more susceptible to the PH. Some common aromatic and diaromatic PH, including three naphthalene compounds, were utilized in bioassays. Naphthalenes were highly toxic. The toxicity of petroleum products is closely related to aromatic hydrocarbon content, especially the naphthalenes and related hydrocarbons.

  7. Environmental impact of aquaculture-sedimentation and nutrient loadings from shrimp culture of the southeast coastal region of the Bay of Bengal.

    Science.gov (United States)

    Das, Biplob; Khan, Yusuf Sharif Ahmed; Das, Pranab

    2004-01-01

    Nutrient loadings were measure