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Sample records for surficial wetland sediments

  1. Comparison of Pb and Cd adsorption to the surface coatings and surficial sediments collected in Xianghai Wetland

    Institute of Scientific and Technical Information of China (English)

    LI Yu; WANG Xiao-li; WANG Yue; DONG De-ming; ZHANG Hua-peng; LI Qing-shan; LI Xing-chun

    2005-01-01

    Surface coatings and surficial sediments ware obtained in four natural waters in Xianghai Wetland in China to study the role of surface coatings and surficial sediments in controlling the transporting and cycling of heavy metals in aquatic environments. Pb and Cd adsorption to the surface coatings and surficial sediments were measured under controlled laboratory conditions(mineral salts solution with defined speciation, ionic strength 0.05 mol/L, 25℃ and pH 6.0 for surface coatings; and 0.005 mol/L CaCl2 solution, 25℃ and pH 6.0 for surficial sediments). The Langmuir adsorption isotherm was applied to estimate equilibrium coefficients of Pb and Cd adsorption to the surface coatings and surficial sediments, and the component analyses of surface coatings and surficial sediments were also carried out.Correlation analyses between the maximum adsorption of Pb and Cd ( Гmax ) and the components in the surface coatings and surficial sediments suggested that there was a statistically significant trend for Pb and Cd adsorption(Гmax ) to the surface coatings to increase with increasing in contents of Fe and Mn oxides in the surface coatings and surficial sediments. And the metal adsorption abilities of surface coatings were much stronger than those of surficial sediments, highlighting that in the same water, i.e. at the same pH and initial metal concentrations, the metals (such as lead and cadmium) in supernatant were feasible to be adsorbed by surface coatings than surficial sediments. The more importance of surface coatings than surficial sediments for adsorbing and cycling of heavy metals in aquatic environments was evidenced.

  2. Heavy metal concentrations in the soft tissues of swan mussel (Anodonta cygnea) and surficial sediments from Anzali wetland, Iran.

    Science.gov (United States)

    Pourang, N; Richardson, C A; Mortazavi, M S

    2010-04-01

    Concentrations of cadmium, copper, and lead were determined in surficial sediments and the soft tissues (foot and gills) of swan mussel Anodonta cygnea from two sampling sites in Anzali wetland, which is an internationally important wetland registered in the Ramsar Convention. The metal contents in the mussel species from the studied region were comparable to other world areas. In most cases, the levels of the metals either fell within the range for other areas or were lower. There were significant differences between the tissues for the accumulation of Cd and Pb. Only in the case of Pb accumulation in gills significant differences between the specimens from the selected sampling sites could be observed. Age-related correlations were found in the case of Cu accumulation in foot and Cd levels in gills. No weight-dependent trend could be observed for the accumulation of the three elements. There was significant negative width-dependent relationship in the case of Cu. A significant negative correlation was also found between the maximum shell height and Cu accumulation in the gills. The only association among the elements in the selected soft tissues was found between Cd and Pb. Highly significant differences could be found between the sampling sites from the concentration of the elements in sediments point of view. The pattern of metal occurrence in the selected tissues and sediments exhibited the following descending order: Pb, Cu>Cd for gills, Cu>Pb, Cd for foot, and Cu>Pb>Cd for sediments. The mean concentrations of Cd and Pb in the sediments from the study area were higher than the global baseline values and world average shale. In the case of Cu, our results were somewhat higher than the baseline values but well below the world average shale.

  3. Seafloor Surficial Sediments (Deck 41)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Geophysical Data Center (NGDC) "Deck41" database contains surficial sediment descriptions for over 36,000 seafloor samples worldwide. The file was begun...

  4. [Distribution Characteristics, Sources and Pollution Assessment of Trace Elements in Surficial Sediments of the Coastal Wetlands, Northeastern Hainan Island].

    Science.gov (United States)

    Zhang, Wei-kun; Gan, Hua-yang; Bi, Xiang-yang; Wang, Jia-sheng

    2016-04-15

    Totally 128 surficial sediments samples were collected from the coastal wetlands, northeastern Hainan Island and analyzed for their concentrations of 14 elements including Al2O3, Fe2O3, MnO, Cu, Ni, Sr, Zn, V, Pb, Cr, Zr, As, Cd and Hg, TOC and grain sizes. The mean concentrations of trace metals V, Cr, Ni, Cu, Zn, As, Pb, Cd and Hg were (40.13 +/- 32.65), (35.92 +/- 26.90), (13.03 +/- 11.46), (11.56 +/- 10.27)-, (48.75 +/- 27.00), (5.48 +/- 1.60), ( 18.70 +/- 8.66), (0.054 +/- 0.045 ), (0.050 +/- 0.050) microg x g(-1), respectively, which were much lower than those in Pearl River Estuary, Yangzi River Estuary, Bohai Bay, upper crust and average shale. The average concentrations of Sr and Zr were much higher, reaching up to (1253.60 +/- 1649.58) microg x g(-1) and (372.40 +/- 516.49) microg x g(-1), respectively. The spatial distribution patterns of Al2O3, Fe2O3, MnO, Cu, Ni, Zn, V, Pb, Cr, Cd and Hg concentrations were the same as each other except for those of As, Sr and Zr. Generally, relatively high concentrations of these elements only appeared in the Haikou Bay, Nandu estuary, Dongzhai Harbor, Qinglan Harbor and Xiaohai in study area. The factor analysis revealed that the trace elements Al2O3 Fe2O3, MnO, Cu, Ni, Zn, V, Pb, Cr and part of Hg were mainly originated from the rock material by natural weathering processes, while the Cd and a part of Hg were from the biological source controlled by TOC. As and part of MnO were influenced by anthropogenic source, especially by aquacultures. Zr and some MnO were derived from heavy minerals dominated by the coarse grain of sediments. In contrast to the ERL, ERM and the results of enrichment factors (EF) , the environment of study area was good in general and the degree of contamination by trace elements was low on the whole. However, there are still some places where anthropogenic input have caused serious enrichments of trace elements and the occasional adverse effect on benthic organism induced by Ni could probably

  5. Offshore Surficial Sediment

    Data.gov (United States)

    California Department of Resources — This data layer (PAC_EXT.txt and PAC_PRS.txt) represents two of five point coverages of known sediment samples, inspections, and probes from the usSEABED data...

  6. Deck41 Surficial Seafloor Sediment Description Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Deck41 is a digital summary of surficial sediment composition for 36,401 seafloor samples worldwide. Data include collecting source, ship, cruise, sample id,...

  7. Long Island Sound Surficial Sediment Data (LISSEDDATA)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Many scientific questions and policy issues related to sediments in Long Island Sound require data of historical, regional and interdisciplinary scope. Existent data...

  8. Surficial Sediment Facies features near Shorty's Island on the Kootenai River near Bonners Ferry, ID

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The surficial bed-sediment facies, herein after referred to as the sediment facies, quantitatively describes the dominant sediment substrate on the surface of the...

  9. Surficial Sediment Distributions off Eastern Cape Cod, Massachusetts (CC_SEDDIST.SHP, Geographic, WGS84)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set shows the distribution of surficial sediments offshore of northern and eastern Cape Cod, Massachusetts. This interpretation is based on data collected...

  10. Dissolved and Bubble Gas Concentrations in Sandy Surficial Sediments of the West Florida Sand Sheet

    Science.gov (United States)

    2016-06-21

    Dissolved and Bubble Gas Concentrations in Sandy Surficial Sediments of the West Florida Sand Sheet Christopher Martens Dept. of Marine Sciences CB...TITLE AND SUBTITLE Dissolved and Bubble Gas Concentrations in Sandy Surficial Sediments of the West Florida Sand Sheet 5a. CONTRACT NUMBER 5b. GRANT...was noted that there was substantially higher organic material in the shallow troughs of the sand ripples than on the crests. Most of this appears

  11. Surficial sediment distribution and the associated net sediment transport pattern in the Pearl River Estuary, South China

    NARCIS (Netherlands)

    Zhang, W.; Zheng, J.H.; Ji, X.M.; Hoitink, A.J.F.; van der Vegt, M.

    2013-01-01

    Spatial variations in grain-size parameters contain information on sediment transport patterns. Therefore, in this study, 106 surficial sediment samples taken from the Pearl River Estuary (PRE), South China, were analyzed, to better understand the net sediment transport pattern in this region. The P

  12. Surficial Sediment Facies features near the Myrtle Bend Confluence with the Kootenai River near Bonners Ferry, ID

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The surficial bed-sediment facies, herein after referred to as the sediment facies, quantitatively describes the dominant sediment substrate on the surface of the...

  13. Surficial and vertical distribution of heavy metals in different estuary wetlands in the Pearl river, South China

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Honggang; Cui, Baoshan [State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Beijing Normal University, Beijing (China); Zhang, Kejiang [Xinjiang Research Center of Water and Wastewater Treatment, Xinjiang Deland Co., LTD., Urumqi (China)

    2012-10-15

    A total of 87 soil profiles sampled from five types of wetlands in the Pearl River estuary were analyzed to investigate the surficial and vertical distributions of heavy metals (Cd, Cr, Cu, Ni, Pb, and Zn). The results show that wetlands directly connected with rivers (e.g., riparian wetlands, estuarine wetlands, and mangrove wetlands) has much higher metal concentrations than those indirectly connected with rivers (e.g., pond wetlands and reclaimed wetlands). The river water is the major pollution source for all investigated heavy metals. The vertical distribution of heavy metals can be classified into three patterns: (i) linear distribution pattern. The concentration of heavy metals gradually decreases with an increase in soil depth (for riparian and estuarine wetlands); (ii) irregular and stable pattern (for pond and reclaimed wetlands); and (iii) middle enrichment pattern (for mangrove wetlands). In addition to river-borne inputs, a variety of vegetation composition, hydraulic conditions, and human activities also contribute to the variation in distribution of heavy metals in different wetlands. Soil properties (e.g., particle size, pH, salinity, and SOM) also affect the distribution of trace metals in each soil layer. The major pollution source of heavy metals is industrial wastewater. Other sources include agriculture and domestic premises, and atmospheric deposition. This study provides a sound basis for the risk assessment of heavy metals in the studied wetlands and for wetland conservation in general. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  14. Surficial sediments of the continental shelf off Karnataka

    Digital Repository Service at National Institute of Oceanography (India)

    Hashimi, N.H.; Nair, R.R.

    on the inner shelf. X-ray mineralogy of the silt fraction of the sediments shows the presence of quartz, calcite, aragonite and orthoclase as major minerals. Some of the sedimentary processes effecting the distribution of these sediments are discussed...

  15. Wetland Restoration and Sediment Removal

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — In 2008, Minnesota’s Private Lands Program and Wetland Management Districts began to compare different methods of restoring prairie pothole wetlands to see if there...

  16. Distribution of surficial sediments in the Southern Evoikos and Petalioi Gulfs, Greece

    Directory of Open Access Journals (Sweden)

    A.P. KARAGEORGIS

    2012-12-01

    Full Text Available A series of 123 surficial sediment samples from the Southern Evoikos and Petalioi Gulfs was studied for grain-size properties, carbonate content and mineralogical composition. Distribution of the sediments revealed two sedimentary provinces. The first concerns the Southern Evoikos Gulf, characterised by silty sediments with relatively low carbonate content. Quartz, feldspars, micas, clay and carbonate minerals are the major mineralogical components of the sediments. These sediments are the result of the Asopos River supply during Holocene and they contribute to the formation of smooth bottom morphology. The second province concerns the Petalioi Gulf (Northern and Southern, where the surficial sediments are mainly sandy and characterised by very high carbonate content. Their mineralogical composition reflects the lithology of the drainage basin. Since the modern terrigenous solid supply is limited, these sediments are not considered as products of recent sedimentation, but older deposits (relict sands. Their presence at such depths is justified by sea-level fluctuations and their preservation is due to the low sedimentation rate in the Petalioi Gulf, in combination with the strong hydrodynamic status of the area.

  17. Long Island Sound Surficial Sediment Data (LISSEDDATA.SHP)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Many scientific questions and policy issues related to sediments in Long Island Sound require data of historical, regional and interdisciplinary scope. Existent data...

  18. Long Island Sound Surficial Sediment Data (LISSEDDATA.SHP)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Many scientific questions and policy issues related to sediments in Long Island Sound require data of historical, regional and interdisciplinary scope. Existent data...

  19. Sediment pollution and dynamic in the Mar Piccolo of Taranto (southern Italy): insights from bottom sediment traps and surficial sediments.

    Science.gov (United States)

    Bellucci, Luca Giorgio; Cassin, Daniele; Giuliani, Silvia; Botter, Margherita; Zonta, Roberto

    2016-07-01

    Major and trace element, PAH, and PCB concentrations were measured in surface sediments and particles from sediment traps collected in the First and Second Basin of the Mar Piccolo (Gulf of Taranto) in two periods (June-July and August-September, 2013). The aim of the study was to evaluate pollution degree, sediment transport and particle redistribution dynamic within the area. Results confirm the higher contamination of sediments from the First Basin observed by previous researches, particularly for Cu, Hg, Pb, total PAHs, and total PCBs. Advective transport from the First to the Second Basin appears to be the leading transfer mechanism of particles and adsorbed contaminants, as evidenced by measured fluxes and statistical analyses of contaminant concentrations in surficial sediments and particles from sediment traps. Long-range selective transports of PAHs and microbial anaerobic degradation processes for PCBs have been also observed. These results are limited to a restricted time window but are consistent with the presence of transport fluxes at the bottom of the water column. This mechanism deserves further investigation and monitoring activities, potentially being the main responsible of pollutant delivering to the less contaminated sectors of the Mar Piccolo.

  20. Control of sediment deposition rates in two mid-Atlantic Coast tidal freshwater wetlands

    Science.gov (United States)

    Darke, A. K.; Megonigal, J. P.

    2003-05-01

    Eustatic sea level rise and rapidly increasing coastal development threaten tidal freshwater wetlands. Sediment deposition is one process that affects their ability to maintain surface elevations relative to adjacent rivers. Sediment dynamics in salt marshes have been studied extensively, but little is known about the factors that control sediment deposition rates in tidal freshwater wetlands. We examined geomorphic, hydrological, and biotic factors that may influence sedimentation in two tidal freshwater wetlands that fell at opposite ends of the riverine-estuarine continuum. Our data demonstrate that sediment dynamics are highly variable among tidal freshwater wetlands, and are influenced by the location of the wetland on the continuum. Sediment deposition was up to 10 times higher during the growing season at the downstream site than the upstream site. Plant density and height were highly correlated with sediment deposition rates at the downstream site ( r≥0.92, p≤0.009) but not at the upstream site. Elevation, flood depth, and flood duration were correlated with deposition rates only when each site/season combination was considered separately. River suspended sediment and surficial floodwater suspended sediment concentrations were significantly higher at the downstream site ( p=0.02 and p=0.04, respectively). These data suggest that vegetation is important in determining sediment deposition rates when river suspended sediment is not limiting, which is not always the case. Longer flood duration increased sediment deposition, but was of secondary importance. Land use and proximity to the turbidity maximum (near the forward extent of the salt water intrusion) appear to be critically important in determining river suspended sediment availability in the tidal freshwater zone of the Mattaponi River, VA.

  1. Heavy mineral distribution in the surficial sediments from the eastern continental margin of India and their implications on palaeoenvironment

    Digital Repository Service at National Institute of Oceanography (India)

    Mislankar, P.G.; Gujar, A.R.

    Heavy mineral distribution from the surficial sediments of the Eastern Continental Margin of India, between Machilipatnam and Gopalpur shows that their concentration ranges from 0.4 to 13.9%. Heavy minerals such as opaques, (ilmenite, magnetite...

  2. Surficial sediment data from Boston Harbor collected during USGS Field Activity 04019 (SEDGRABS, UTM 19, WGS84)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set includes the locations, identifiers, grain-size data and(or) textural descriptions of surficial sediments collected at stations based on topographic...

  3. Composition And Characteristic Of The Surficial Sediments In The Southern Corniche Of Jeddah, Red Sea Coast

    Directory of Open Access Journals (Sweden)

    Talha A Al-Dubai

    2017-03-01

    Full Text Available This work discusses the composition and characteristic of the surficial sediments in the southern corniche of Jeddah, Saudi Red Sea coast, in an attempt to infer the surficial distribution pattern of minerals and provenance of sediments. Twenty-six superficial sediments samples were collected from backreef and forereef areas and were analyzed for grain size, CaCO3 content, and mineralogy. The textural of grain size range from gravel to mud fraction. The mud-dominated substrates (<63 µm occur generally in the back-reef area near the shoreline (sheltered area and in the lagoon. Gravel rich-sediments are mostly found in forereef regions. The highest content of aragonite and Mg-calcite occur in the forereef area, probably because to suitability the forereef region for chemical and biochemical precipitation of these minerals. High Mg-calcite and Dolomite are low in both the regions. The pyrite occurs in lagoon; this indicates the reductive conditions in this part. However, on the contrary the percentage of carbonate minerals were low in the backreef-flat area, which could be attributed to the supply of non-carbonate terrigenous materials. The terrigenous material contains quartz, k-feldspar, plagioclase and amphibole minerals and are dominant in backreef-flat area with averages of 12.7%, 7.13%, 2.93% and 0.65%, respectively. Their abundance could be attributed to the supply of terrigenous materials by Aeolian deposits and intermittent Wadis.

  4. Distribution Characteristics, Sources and Pollution Assessment of Trace Elements in Surficial Sediments of the Coastal Wetlands, Northeastern Hainan Island%海南东北部滨海湿地沉积物微量元素分布特征、来源及污染评价

    Institute of Scientific and Technical Information of China (English)

    张卫坤; 甘华阳; 闭向阳; 王家生

    2016-01-01

    Totally 128 surficial sediments samples were collected from the coastal wetlands, northeastern Hainan Island and analyzed for their concentrations of 14 elements including Al2 O3 , Fe2 O3 , MnO, Cu, Ni, Sr, Zn, V, Pb, Cr, Zr, As, Cd and Hg, TOC and grain sizes. The mean concentrations of trace metals V, Cr, Ni, Cu, Zn, As, Pb, Cd and Hg were (40. 13 ± 32. 65), (35. 92 ± 26. 90), (13. 03 ± 11. 46), (11. 56 ± 10. 27), (48. 75 ± 27. 00), (5. 48 ± 1. 60), (18. 70 ± 8. 66), (0. 054 ± 0. 045), (0. 050 ± 0. 050)μg•g-1 , respectively, which were much lower than those in Pearl River Estuary, Yangzi River Estuary, Bohai Bay, upper crust and average shale. The average concentrations of Sr and Zr were much higher, reaching up to (1 253. 60 ± 1 649. 58) μg•g-1 and (372. 40 ± 516. 49)μg•g-1 , respectively. The spatial distribution patterns of Al2 O3 , Fe2 O3 , MnO, Cu, Ni, Zn, V, Pb, Cr, Cd and Hg concentrations were the same as each other except for those of As, Sr and Zr. Generally, relatively high concentrations of these elements only appeared in the Haikou Bay, Nandu estuary, Dongzhai Harbor, Qinglan Harbor and Xiaohai in study area. The factor analysis revealed that the trace elements Al2 O3, Fe2 O3 , MnO, Cu, Ni, Zn, V, Pb, Cr and part of Hg were mainly originated from the rock material by natural weathering processes, while the Cd and a part of Hg were from the biological source controlled by TOC. As and part of MnO were influenced by anthropogenic source, especially by aquacultures. Zr and some MnO were derived from heavy minerals dominated by the coarse grain of sediments. In contrast to the ERL, ERM and the results of enrichment factors ( EF) , the environment of study area was good in general and the degree of contamination by trace elements was low on the whole. However, there are still some places where anthropogenic input have caused serious enrichments of trace elements and the occasional adverse effect on benthic organism induced by Ni could

  5. Depth shapes α- and β-diversities of microbial eukaryotes in surficial sediments of coastal ecosystems.

    Science.gov (United States)

    Gong, Jun; Shi, Fei; Ma, Bin; Dong, Jun; Pachiadaki, Maria; Zhang, Xiaoli; Edgcomb, Virginia P

    2015-10-01

    Little is known about the relative influence of historic processes and environmental gradients on shaping the diversity of single-celled eukaryotes in marine benthos. By combining pyrosequencing of 18S ribosomal RNA genes with data on multiple environmental factors, we investigated the diversity of microeukaryotes in surficial sediments of three basins of the Yellow Sea Large Marine Ecosystem. A considerable proportion (about 20%) of reads was affiliated with known parasitoid protists. Dinophyta and Ciliophora appeared dominant in terms of relative proportion of reads and operational taxonomic unit (OTU) richness. Overall, OTU richness of benthic microeukaryotes decreased with increasing water depth and decreasing pH. While community composition was significantly different among basins, partial Mantel tests indicated a depth-decay pattern of community similarity, whereby water depth, rather than geographic distance or environment, shaped β-diversity of benthic microeukaryotes (including both the abundant and the rare biosphere) on a regional scale. Similar hydrographic and mineralogical factors contributed to the biogeography of both the abundant and the rare OTUs. The trace metal vanadium had a significant effect on the biogeography of the rare biosphere. Our study sheds new light on the composition, diversity patterns and underlying mechanisms of single-celled eukaryote distribution in surficial sediments of coastal oceans.

  6. Nature, Source and Composition of Volcanic Ash in Surficial Sediments Around the Zhongsha Islands

    Institute of Scientific and Technical Information of China (English)

    YAN Quanshu; SHI Xuefa; WANG Xinyu

    2008-01-01

    Volcanic detrital sediments are a unique indicator for reconstructing the petrogenetie evolution of submarine volcanic terrains. Volcanic ash in surficial sediments around the Zhongsha Islands includes three kinds of volcanogenic detritus, i.e., brown volcanic glass, colorless volcanic glass and volcanic scoria. The major element characteristics show that bimodal volcanic activity may have taken place in the northern margin of the South China Sea, with brown volcanic glass and colorless volcanic glass repre-senting the maric end-member and felsie end-member, respectively. Fractional crystallization is the main process for magma evolu-tion. The nature of the volcanic activity implies that the origin of volcanic activity was related to extensional tectonic settings, which is corresponding to an extensional geodynamie setting in the Xisha Trench, and supports the notion, which is based on geophysical data and petrology, that there may exist a mantle plume around the Hainan Island.

  7. Hydrocarbon biodegradation in intertidal wetland sediments.

    Science.gov (United States)

    McGenity, Terry J

    2014-06-01

    Intertidal wetlands, primarily salt marsh, mangrove and mudflats, which provide many essential ecosystem services, are under threat on numerous fronts; a situation that is made worse by crude-oil pollution. Microbes are the main vehicle for remediation of such sediments, and new discoveries, such as novel biodegradation pathways, means of accessing oil, multi-species interactions, and community-level responses to oil addition, are helping us to understand, predict and monitor the fate of oil. Despite this, there are many challenges, not least because of the heterogeneity of these ecosystems and the complexity of crude oil. For example, there is growing awareness about the toxicity of the oxygenated products that result from crude-oil weathering, which are difficult to degrade. This review highlights how developments in areas as diverse as systems biology, microbiology, ecology, biogeochemistry and analytical chemistry are enhancing our understanding of hydrocarbon biodegradation and thus bioremediation of oil-polluted intertidal wetlands.

  8. Chromium Distribution and Spatial Variations in the Finer Sediment Grain Size Fraction and Unfractioned Surficial Sediments on Nyanza Gulf, of Lake Victoria (East Africa

    Directory of Open Access Journals (Sweden)

    Job Mwamburi

    2016-01-01

    Full Text Available Surficial sediments collected from the Nyanza Gulf of Lake Victoria (East Africa were used to determine spatial concentrations of Cr and determine differences in contents of the unfractioned (whole sediment and the finer grain size sediments, establishing any changes in Cr enrichment and potential ecological risks using sediment quality guidelines. A single pollution index was also used to evaluate level of Cr contamination. The spatial mean Cr contents in the <63 µm (silt-clay fraction were found to be significantly lower than those in the unfractioned sediments, but with a strong linear positive correlation. The study results show decreasing spatial amounts of Cr in surficial sediments of the Nyanza Gulf, when compared to a study done 20 years earlier. However, the 95% confidence limits of the overall mean Cr in unfractioned sediments exceed the threshold effect concentration (TEC, indicating the potential for Cr remobilization from sediments. In general the sediment enrichment is evidence of possible dominance of lithogenous sources of Cr in the surface lake sediments, with potential anthropogenic sources from the drainage system and nearshore urban areas. The sediments are unpolluted with respect to geoaccumulation index, and sediment enrichment factors suggest a minor to moderate enrichment of Cr in surficial sediments of three sites around the Nyanza Gulf zones and around the river mouth in the main lake.

  9. Distribution and composition characteristics of heavy minerals in surficial sediment of Minjiang Estuary

    Institute of Scientific and Technical Information of China (English)

    XU Maoquan; XU Wenbin; SUN Meiqin

    2005-01-01

    Heavy minerals with a size range of 0.125~0.250 mm in the surficial sediment of Minjiang Estuary are studied. Thirty-four heavy minerals have been identified, with an average content of 1.92%. Major minerals include magnetite, epidote, hematite, hornblende, ilmenite, and zircon mica. These types are the same as those in the 0.063~0.125 mm range; however, the average content is lower, which reveals that the heavy minerals in Minjiang Estuary are mainly enriched in the very-fine sand fraction. According to the content and distribution characteristics of the major heavy minerals, Minjiang Estuary can be divided into 4 mineral assemblage zones. In each zone the assemblage of heavy minerals is greatly affected by the hydrodynamic condition and the sedimentary environment. Heavy mineral types also show that detrital matters in Minjiang Estuary are originated from the weathering and erosion of the bedrock in the Minjiang River drainage area.

  10. Seasonal mercury transformation and surficial sediment detoxification by bacteria of Marano and Grado lagoons

    Science.gov (United States)

    Baldi, Franco; Gallo, Michele; Marchetto, Davide; Fani, Renato; Maida, Isabel; Horvat, Milena; Fajon, Vesna; Zizek, Suzana; Hines, Mark

    2012-11-01

    Marano and Grado lagoons are polluted by mercury from the Isonzo River and a chlor-alkali plant, yet despite this contamination, clam cultivation is one of the main activities in the region. Four stations (MA, MB, MC and GD) were chosen for clam seeding and surficial sediments were monitored in autumn, winter and summer to determine the Hg detoxifying role of bacteria. Biotransformation of Hg species in surficial sediments of Marano and Grado lagoons was investigated while taking into consideration the speciation of organic matter in the biochemical classes of PRT (proteins), CHO (carbohydrates) and LIP (lipids), water-washed cations and anions, bacterial biomass, Hg-resistant bacteria, some specific microbial activities such as sulfate reduction rates, Hg methylation rates, Hg-demethylation rates, and enzymatic ionic Hg reduction. MeHg in sediments was well correlated with PRT content, whereas total Hg in sediments correlated with numbers of Hg-resistant bacteria. Correlations of the latter with Hg-demethylation rates in autumn and winter suggested a direct role Hg-resistant bacteria in Hg detoxification by producing elemental Hg (Hg0) from ionic Hg and probably also from MeHg. MeHg-demethylation rates were ˜10 times higher than Hg methylation rates, were highest in summer and correlated with high sulfate reduction rates indicating that MeHg was probably degraded in summer by sulfate-reducing bacteria via an oxidative pathway. During the summer period, aerobic heterotrophic Hg-resistant bacteria decreased to Staphylococcus and Bacillus) and two Gram-negative (Stenotrophomonas and Pseudomonas). Two were able to produce Hg0, but just one contained a merA gene; while other two strains did not produce Hg0 even though they were able to grow at 5 μg ml of HgCl2. Lagoon sediments support a strong sulfur cycle in summer that controls Hg methylation and demethylation. However, during winter, Hg-resistant bacteria that are capable of degrading MeHg via the mer

  11. Polychlorinated biphenyls and pesticides in surficial coastal sediments of the Ligurian Sea

    Energy Technology Data Exchange (ETDEWEB)

    Bertolotto, R.M.; Cuneo, C.; Albanese, S. [ARPAL, Direzione Scientifica, Genova (Italy); Magherini, A. [ARPAL, Dipartimento di Genova, Genova (Italy); Frignani, M.; Bellucci, L.G.; Alvarado-Aguilar, D. [ISMAR, Sezione di Geologia Marina, Bologna (Italy)

    2004-09-15

    , sources and potential toxicological significance of PCBs and chlorinated pesticides in surficial sediments of the marine coastal area of the Ligurian Sea.

  12. Stability studies of surficial sediments in the Wilmington-Lindenkohl Canyons area, eastern U.S. margin

    Science.gov (United States)

    Almagor, G.; Bennett, R.H.; Mc Gregor, B.A.; Shephard, L.E.

    1982-01-01

    Stability analysis, based on infinite slope analysis and geotechnical data from a suite of 34 cores collected from the continental slope between Wilmington and Lindenkohl Canyons, indicates that the Quaternary surficial silty clay sediments on gentle slopes are stable; that sediment stability on steeper slopes (14??-19??) is marginal; and that on precipitous slopes (>50??) only a thin veneer of unconsolidated sediments can exist. Small earthquake-induced accelerations or the effects of internal waves can result in slope sediment instabilities. ?? 1982 A. M. Dowden, Inc.

  13. Distinct bacterial communities in surficial seafloor sediments following the 2010 Deepwater Horizon blowout

    Directory of Open Access Journals (Sweden)

    Tingting Yang

    2016-09-01

    Full Text Available A major fraction of the petroleum hydrocarbons discharged during the 2010 Macondo oil spill became associated with and sank to the seafloor as marine snow flocs. This sedimentation pulse induced the development of distinct bacterial communities. Between May 2010 and July 2011, full-length 16S rRNA gene clone libraries demonstrated bacterial community succession in oil-polluted sediment samples near the wellhead area. Libraries from early May 2010, before the sedimentation event, served as the baseline control. Freshly deposited oil-derived marine snow was collected on the surface of sediment cores in September 2010, and was characterized by abundantly detected members of the marine Roseobacter cluster within the Alphaproteobacteria. Samples collected in mid-October 2010 closest to the wellhead contained members of the sulfate-reducing, anaerobic bacterial families Desulfobacteraceae and Desulfobulbaceae within the Deltaproteobacteria, suggesting that the oil-derived sedimentation pulse triggered bacterial oxygen consumption and created patchy anaerobic microniches that favored sulfate-reducing bacteria. Phylotypes of the polycyclic aromatic hydrocarbon-degrading genus Cycloclasticus, previously found both in surface oil slicks and the deep hydrocarbon plume, were also found in oil-derived marine snow flocs sedimenting on the seafloor in September 2010, and in surficial sediments collected in October and November 2010, but not in any of the control samples. Due to the relative recalcitrance and stability of polycyclic aromatic compounds, Cycloclasticus represents the most persistent microbial marker of seafloor hydrocarbon deposition that we could identify in this dataset. The bacterial imprint of the DWH oil spill had diminished in late November 2010, when the bacterial communities in oil-impacted sediment samples collected near the Macondo wellhead began to resemble their pre-spill counterparts and spatial controls. Samples collected in summer

  14. Hydrodynamics and Associated Sediment Transport over Coastal Wetlands in Quanzhou Bay,China

    Institute of Scientific and Technical Information of China (English)

    WANG Ai-jun

    2011-01-01

    Coastal salt marshes represent an important coastal wetland system.In order to understand the differences between boundary layer parameters of vegetated and unvegetated areas,as well as the mechanisms of sediment transport,several electromagnetic current meters(AEM HR,products of Alec Electronics Co.Ltd.)were deployed in coastal wetlands in Quanzhou Bay,China,to measure current velocity.During the low tide phase,the surficial sediment was collected at 10 m intervals.In situ measurements show that the current velocities on the bare flat were much higher than those in the Spartina alterniora marsh.Current velocity also varied with distance from marsh edge and plant canopy height and diameter.Around 63% of the velocity profiles in the tidal creek can be described by a logarithmic equation.Over the bare flat and Spartina alterniglora marsh,a logarithmic profile almost occurs during the flood tide phase.Sediment analysis shows that mean grain size was 6.7(D along the marsh edge,and surface sediments were transported from bare flat to marsh;the tidal creeks may change this sediment transport pattern.The hydrodynamics at early flood tide and late ebb tide phases determined the net transport direction within the study area.

  15. Mineralogical correlation of surficial sediment from area drainages with selected sedimentary interbeds at the Idaho National Engineering Laboratory, Idaho

    Energy Technology Data Exchange (ETDEWEB)

    Bartholomay, R.C.

    1990-08-01

    Ongoing research by the US Geological Survey at the INEL involves investigation of the migration of radioactive elements contained in low-level radioactive waste, hydrologic and geologic factors affecting waste movement, and geochemical factors that influence the chemical composition of the waste. Identification of the mineralogy of the Snake River Plain is needed to aid in the study of the hydrology and geochemistry of subsurface waste disposal. The US Geological Surveys project office at the Idaho National Engineering Laboratory, in cooperation with the US Department of Energy, used mineralogical data to correlate surficial sediment samples from the Big Lost River, Little Lost River, and Birch Greek drainages with selected sedimentary interbed core samples taken from test holes at the RWMC (Radioactive Waste Management Complex), TRA (Test Reactors Area), ICPP (Idaho Chemical Processing Plant), and TAN (Test Area North). Correlating the mineralogy of a particular present-day drainage area with a particular sedimentary interbed provides information on historical source of sediment for interbeds in and near the INEL. Mineralogical data indicate that surficial sediment samples from the Big Lost River drainage contained a larger amount of feldspar and pyroxene and a smaller amount of calcite and dolomite than samples from the Little Lost River and Birch Creek drainages. Mineralogical data from sedimentary interbeds at the RWMC, TRA, and ICPP correlate with surficial sediment of the present-day big Lost River drainage. Mineralogical data from a sedimentary interbed at TAN correlate with surficial sediment of the present-day Birch Creek drainage. 13 refs., 5 figs., 3 tabs.

  16. Selective extraction and separation of Fe, Mn oxides and organic materials in river surficial sediments

    Institute of Scientific and Technical Information of China (English)

    LI Feng-mei; WANG Xiao-li; LI Yu; GUO Shu-hai; ZHONG Ai-ping

    2006-01-01

    In order to investigate the adsorption mechanism of trace metals to surficial sediments (SSs), a selective extraction procedure was improved in the present work. The selective extraction procedure has been proved to selectively remove and separate Fe, Mn oxides and organic materials (OMs) in the non-residual fraction from the SSs collected in Songhua River, China. After screening different kinds of conventional extractants of Fe and Mn oxides and OMs used for separation of heavy metals in the soils respectively applied to selectively extract Mn oxides, Fe/Mn oxides and OMs. After the extraction treatments, the target components were removed with extraction efficiencies between 86.09%-93.36% for the hydroxylamine hydrochloride treatment, 80.63%-101.09% for the oxalate solution extraction, and 94.76%-102.83% for the hydrogen peroxide digestion, respectively. The results indicate that this selective extraction technology was effective for the extraction and separation of Fe, Mn oxides and OMs in the SSs,and important for further mechanism study of trace metal adsorption onto SSs.

  17. Elemental distributions in surficial sediments and potential offshore mineral resources from the western continental margin of India. Part 2. Potential offshore mineral resources

    Digital Repository Service at National Institute of Oceanography (India)

    Paropkari, A.L.; Mascarenhas, A.; Rao, Ch.M.; PrakashBabu, C.; Murty, P.S.N.

    patterns of ten selected elements is surficial sediments. Part 2 projects the potential offshore mineral resources. Target areas for future exploration and indicated and exploration strategies are recommended. Appendix 1 is a compilation of the bibliography...

  18. Hydrophobic organic contaminants in surficial sediments of Baltimore Harbor: Inventories and sources

    Energy Technology Data Exchange (ETDEWEB)

    Ashley, J.T.F.; Baker, J.E. [Univ. System of Maryland, Solomons, MD (United States). Chesapeake Biological Lab.

    1999-05-01

    The heavily urbanized and industrialized Baltimore Harbor/Patapsco River/Back River system is one of the most highly contaminated regions of the Chesapeake Bay. In June 1996, surficial sediments were collected at 80 sites throughout the subestuarine system, including historically undersampled creek sand embayments. The samples were analyzed for a suite of hydrophobic organic contaminants (HOCs) consisting of 32 polycyclic aromatic hydrocarbons (PAHs) and 113 polychlorinated biphenyl (PCB) congeners. Total PAH and total PCB concentrations ranged from 90 to 46,200 and 8 to 2,150 ng/g dry weight, respectively. There was enormous spatial variability in the concentrations of HOCs, which was not well correlated to grain size or organic carbon content, suggesting nonequilibrium partitioning and/or proximity to sources as important factors explaining the observed spatial variability. High concentrations of both classes of HOCs were localized around major urban stormwater runoff discharges. Elevated PAH concentrations were also centered around the Sparrow`s Point Industrial Complex, most likely a result of the pyrolysis of coal during the production of steel. All but 1 of the 80 sites exceeded the effects range-low (ERL) for total PCBs and, of those sites, 40% exceeded the effects range-medium (ERM), suggesting toxicity to marine benthic organisms would frequently occur. Using principal component analysis, differences in PAH signatures were discerned. Higher molecular weight PAHs were enriched in signatures from sediments close to suspected sources (i.e., urban stormwater runoff and steel production complexes) compared to those patterns observed at sites further from outfalls or runoff. Due to varying solubilities and affinities for organic matter of the individual PAHs, partitioning of the heavier weight PAHs may enrich settling particles with high molecular weight PAHs. Lower molecular weight PAHs, having lower affinity for particles, may travel from the source to a

  19. Sediment transport-based metrics of wetland stability

    Science.gov (United States)

    Ganju, Neil K.; Kirwan, Matthew L.; Dickhudt, Patrick J.; Guntenspergen, Glenn R.; Cahoon, Donald R.; Kroeger, Kevin D.

    2015-01-01

    Despite the importance of sediment availability on wetland stability, vulnerability assessments seldom consider spatiotemporal variability of sediment transport. Models predict that the maximum rate of sea level rise a marsh can survive is proportional to suspended sediment concentration (SSC) and accretion. In contrast, we find that SSC and accretion are higher in an unstable marsh than in an adjacent stable marsh, suggesting that these metrics cannot describe wetland vulnerability. Therefore, we propose the flood/ebb SSC differential and organic-inorganic suspended sediment ratio as better vulnerability metrics. The unstable marsh favors sediment export (18 mg L−1 higher on ebb tides), while the stable marsh imports sediment (12 mg L−1 higher on flood tides). The organic-inorganic SSC ratio is 84% higher in the unstable marsh, and stable isotopes indicate a source consistent with marsh-derived material. These simple metrics scale with sediment fluxes, integrate spatiotemporal variability, and indicate sediment sources.

  20. Surficial sediment character of the Louisiana offshore continental shelf region: a GIS compilation

    Science.gov (United States)

    Williams, S. Jeffress; Arsenault, Matthew A.; Buczkowski, Brian J.; Reid, Jane A.; Flocks, James; Kulp, Mark A.; Penland, Shea; Jenkins, Chris J.

    2007-01-01

    The Louisiana coastal zone, comprising the Mississippi River delta plain stretching nearly 400 km from Sabine Pass at the Texas border east to the Chandeleur Islands at the Mississippi border, represents one of North America’s most important coastal ecosystems in terms of natural resources, human infrastructure, and cultural heritage. At the same time, this region has the highest rates of coastal erosion and wetland loss in the Nation due to a complex combination of natural processes and anthropogenic actions over the past century. Comparison of historical maps dating back to 1855 and recent aerial photography show the Louisiana coast undergoing net erosion at highly variable rates. Rates have increased significantly during the past several decades. Earlier published statewide average shoreline erosion rates were >6 m/yr; rates have increased recently to >10 m/yr. The increase is attributable to collective action of storms, rapid subsidence, and pervasive man-made alterations of the rivers and the coast. In response to the dramatic landloss, regional-scale restoration plans are being developed by a partnership of federal and state agencies for the delta plain that have the objectives of maintaining the barrier islands, reducing wetland loss, and enhancing the natural sediment delivery processes. There is growing awareness that the sustainability of coastal Louisiana's natural resources and human infrastructure depends on the successful restoration of natural geologic processes. Critical to the long term success of restoration is scientific understanding of the geologic history and processes of the coastal zone region, including interactions between the rivers, wetlands, coast, and inner shelf. A variety of geophysical studies and mapping of Late Quaternary sedimentary framework and coastal processes by U.S. Geological Survey and other scientists during the past 50 years document that the Louisiana delta plain is the product of a complex history of cyclic delta

  1. Environmental Controls on Nitrogen and Sulfur Cycles in Surficial Aquatic Sediments

    Directory of Open Access Journals (Sweden)

    Chuanhui eGu

    2012-02-01

    Full Text Available Enhanced anthropogenic inputs of nitrogen (N and sulfur (S have disturbed their biogeochemical cycling in aquatic and terrestrial ecosystems. The N and S cycles interact with one another through competition for labile forms of organic carbon between nitrate-reducing and sulfate-reducing bacteria. Furthermore, the N and S cycles could interact through nitrate (NO3- reduction coupled to S oxidation, consuming NO3- and producing sulfate (SO42-. The research questions of this study were: (1 what are the environmental factors explaining variability in N and S biogeochemical reaction rates in a wide range of surficial aquatic sediments, and (2 which biogeochemical processes are involved when NO3- and/or SO42- are present. The N and S biogeochemical reaction rates were measured on intact surface sediment slices using flow-through reactors. The two terminal electron acceptors (TEA NO3- and SO42- were added either separately or simultaneously and NO3- and SO42- reduction rates as well as NO3- reduction linked to S oxidation were determined. We used redundancy analysis, to assess how environmental variables are related to these rates. Our analysis showed that overlying water pH and salinity were two dominant environmental factors that explain 58% of the variance in the N and S biogeochemical reaction rates when NO3- and SO42- were both present. When NO3- and SO42- were added separately, however, sediment N content in addition to pH and salinity accounted for 62% of total variance of the biogeochemical reaction rates. The SO42- addition had little effect on NO3- reduction; neither did the NO3- addition inhibit SO42- reduction. The presence of NO3- led to SO42- production most likely due to the oxidation of sulfur. Our observations suggest that metal-bound S, instead of free sulfide produced by SO42- reduction, was responsible the S oxidation. The subsequent release of toxic metals from this coupling might have adverse effects on aquatic ecosystems.

  2. Heavy-metal enrichment in surficial sediments in the Oder River discharge area: source or sink for heavy metals?

    Energy Technology Data Exchange (ETDEWEB)

    Shimmield, G. [Department of Geology and Geophysics, University of Edinburgh, West Mains Rd., Edinburgh (United Kingdom); Leipe, T.; Neumann, T. [Institut fuer Ostseeforschung Warnemuende, Seestr. 15, 18119 Rostock (Germany)

    1998-05-01

    The Oder river drains a highly polluted industrial area and enters the Baltic Sea through a system of shallow lagoons. Surficial sediments in the discharge area of the Oder are highly enriched in heavy metals compared to their preindustrial background levels. Pore-water studies in short sediment cores reveal anoxic environments over the entire sediment column, except for a suboxic layer in the uppermost 5 to 20 mm of the sediment where Mn- and Fe-oxyhydroxides are reduced by organic matter. Heavy metals (such as Cu, Zn and Pb) are mobilized within the suboxic zones in the inner lagoon (represented by the Oder Lagoon) and in the open Baltic (represented by the Arkona Basin). The Achterwasser, located between the Oder Lagoon and the Arkona Basin, is directly affected by sea-level fluctuations in the Baltic. Pore-water studies indicate that, in contrast to the situation in the Oder Lagoon and Arkona Basin, surficial sediments of the Achterwasser represent a sink for heavy metals. This is associated with the high rate of Fe-sulphide formation occurring there, at least seasonally during salt-water inflow.(Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  3. The use of vintage surficial sediment data and sedimentary cores to determine past and future trends in estuarine metal contamination (Sydney estuary, Australia).

    Science.gov (United States)

    Birch, G F; Chang, C-H; Lee, J-H; Churchill, L J

    2013-06-01

    The objectives of the present investigation were to determine past trends in sediment contamination and possibly predict future trends. Multiple vintages of surficial sediment metal data, from a quasi-decadal 'Status and Trends' programme, were used to provide large-scale spatial information on current status and temporal change. This information was augmented by sediment cores, specifically located to verify surface sediment data and to determine trends at major points of stormwater discharge. The data obtained indicate that surficial sediment metal concentrations have declined, since about the early 1990s, in extensive parts of the upper and central estuaries and have increased slightly in the lower estuary, due mainly to a down-estuary shift in industry and urbanisation. Declining surficial sediment metal concentrations is due to a movement of industry out of the catchment, especially from foreshore areas and the introduction of regulation, which prevent pollutants being discharged directly to the estuary. The major present-day source of metals is stormwater, with minor inputs from the main estuary channel into embayments and runoff from previously contaminated mainland sites. Modelled relaxation rates are optimistic as high metal concentrations in stormwater will slow predicted rates. Stormwater remediation should be the main managerial focus for this estuary. Multiple vintages of surficial sediment metal data covering the past 30 years, supplemented by sedimentary core data, have allowed past and future contamination trends to be determined. This type of science-based information provides an important tool for strategic management of this iconic waterway.

  4. Modeling the source contribution of heavy metals in surficial sediment and analysis of their historical changes in the vertical sediments of a drinking water reservoir

    Science.gov (United States)

    Wang, Guoqiang; A, Yinglan; Jiang, Hong; Fu, Qing; Zheng, Binghui

    2015-01-01

    Increasing water pollution in developing countries poses a significant threat to environmental health and human welfare. Understanding the spatial distribution and apportioning the sources of pollution are important for the efficient management of water resources. In this study, ten types of heavy metals were detected during 2010-2013 for all ambient samples and point sources samples. A pollution assessment based on the surficial sediment dataset by Enrichment Factor (EF) showed the surficial sediment was moderately contaminated. A comparison of the multivariate approach (principle components analysis/absolute principle component score, PCA/APCS) and the chemical mass balance model (CMB) shows that the identification of sources and calculation of source contribution based on the CMB were more objective and acceptable when source profiles were known and source composition was complex. The results of source apportionment for surficial heavy metals, both from PCA/APCS and CMB model, showed that the natural background (30%) was the most dominant contributor to the surficial heavy metals, followed by mining activities (29%). The contribution percentage of the natural background was negatively related to the degree of contamination. The peak concentrations of many heavy metals (Cu, Ba, Fe, As and Hg) were found in the middle layer of sediment, which is most likely due to the result of development of industry beginning in the 1970s. However, the highest concentration of Pb appeared in the surficial sediment layer, which was most likely due to the sharp increase in the traffic volume. The historical analysis of the sources based on the CMB showed that mining and the chemical industry are stable sources for all of the sections. The comparing of change rates of source contribution versus years indicated that the composition of the materials in estuary site (HF1) is sensitive to the input from the land, whereas center site (HF4) has a buffering effect on the materials from

  5. Processing RoxAnn sonar data to improve its categorization of lake bed surficial sediments

    Science.gov (United States)

    Cholwek, Gary; Bonde, John; Li, Xing; Richards, Carl; Yin, Karen

    2000-01-01

    To categorize spawning and nursery habitat for lake trout in Minnesota's near shore waters of Lake Superior, data was collected with a single beam echo sounder coupled with a RoxAnn bottom classification sensor. Test areas representative of different bottom surficial substrates were sampled. The collected data consisted of acoustic signals which showed both depth and substrate type. The location of the signals was tagged in real-time with a DGPS. All data was imported into a GIS database. To better interpret the output signal from the RoxAnn, several pattern classifiers were developed by multivariate statistical method. From the data a detailed and accurate map of lake bed bathymetry and surficial substrate types was produced. This map will be of great value to fishery and other natural resource managers.

  6. Boron in Pariette Wetland Sediments, Aquatic Vegetation & Benthic Organisms

    Science.gov (United States)

    Vasudeva, P.; Jones, C. P.; Powelson, D.; Jacobson, A. R.

    2015-12-01

    The Pariette Wetlands are comprised of 20 ponds located in Utah's Uintah Basin. Boron concentration in the Pariette Wetlands have been observed to exceed the total maximum daily limit of 750 µg L-1. Considering water flow in and out of the wetlands, boron is accumulating within the wetlands where it is sorbed to sediments and bioconcentrated by wetland plant and macro invertebrates. Since boron is an avian teratogen, an estimate of boron ingestion exposure is warranted. Samples from 3 of the 23 Pariette Wetland ponds with one pond near the inlet, one near the outlet, and one in the middle were collected. Five sampling points were designated along a 100 m transect of each pond. At each sampling point duplicate (or triplicate) samples of water, sediments, benthic organisms and wetland vegetation were collected. The sediments were collected with a KB-corer and divided at depths of 0-2 cm, 2-7 cm, and 7+ cm from the sediment surface. Sample splits were sent to the USU Bug lab for identification of invertebrate species. Whenever this transect was not intercepting vegetation, 2-3 additional sample sites were identified at the pond within stands of representative vegetation where bird nests are located. The plant parts used for boron analyses will include seeds, shoot and roots of vascular plants, as well as algae or duckweeds skimmed from the surface. Samples were processed within 2 days of collection. Water samples filtered through a 0.45 μ membrane filter were analyzed for DOC, pH and ECe. The dried and washed vegetation samples were ground and stored. The benthic organisms and macro invertebrates were netted at the water surface. The dried samples were weighed, ground and stored. Samples were weighed, oven dried and reweighed. For plant and macro-invertebrate samples, a nitric and hydrogen peroxide digestion procedure is used to dissolve environmentally available elements. The Hot Water extraction and DTPA-Sorbitol extraction were compared to estimate wetland plant

  7. C:N:P Molar Ratios, Sources and 14C Dating of Surficial Sediments from the NW Slope of Cuba.

    Directory of Open Access Journals (Sweden)

    Guadalupe de la Lanza Espino

    Full Text Available The surficial sediments recovered from 12 sites located near the channel axis of the Florida Straits and the lower slope off NW Cuba were analyzed for total organic carbon (TOC, nitrogen (TN, phosphorus (TP, elemental C:N:P ratios, C and N isotopic values, and 14C dating. The depth profiles of TOC, TN, and TP (0-18 cm displayed a downcore trend and a significant variation. The TOC values were low (0.15 to 0.62%; 66 to 516 µmol g(-1. Sites near the island's lower slope had lower TOC average concentrations (158-333 µmol g(-1 than those closer to the channel axis (averaging 341-516 µmol g(-1; p <0.05. The TN concentrations near the lower slope attained 0.11% (80 µmol g(-1, whereas, towards the channel axis, they decreased to 0.07% (55 µmol g(-1; p<0.05. The C:N ratios ranged from 1.9 to 10.2. The mean molar C:N ratio (5.4 indicated a marine hemipelagic deposition. The TP was lower at sites near the lower slope (38.4 to 50.0 µmol gv; 0.12% to 0.16% than those near the channel axis (50.0 to 66 µmol g(-1; 0.15 to 0.21%. C:P fluctuated from 7.7 to 14.1 in the surficial sediment layer. The bulk organic δ13Corg and δ15N values confirmed pelagic organic sources, and the 14C dating revealed that the sediments were deposited during the Holocene (1000-5000 yr BP. We suggest that the hydrodynamic conditions in the Straits influence vertical and advective fluxes of particulate organic material trapped in the mixed-layer, which reduces the particulate matter flux to the seabed.

  8. C:N:P Molar Ratios, Sources and 14C Dating of Surficial Sediments from the NW Slope of Cuba.

    Science.gov (United States)

    de la Lanza Espino, Guadalupe; Soto, Luis A

    2015-01-01

    The surficial sediments recovered from 12 sites located near the channel axis of the Florida Straits and the lower slope off NW Cuba were analyzed for total organic carbon (TOC), nitrogen (TN), phosphorus (TP), elemental C:N:P ratios, C and N isotopic values, and 14C dating. The depth profiles of TOC, TN, and TP (0-18 cm) displayed a downcore trend and a significant variation. The TOC values were low (0.15 to 0.62%; 66 to 516 µmol g(-1)). Sites near the island's lower slope had lower TOC average concentrations (158-333 µmol g(-1)) than those closer to the channel axis (averaging 341-516 µmol g(-1); p <0.05). The TN concentrations near the lower slope attained 0.11% (80 µmol g(-1)), whereas, towards the channel axis, they decreased to 0.07% (55 µmol g(-1); p<0.05). The C:N ratios ranged from 1.9 to 10.2. The mean molar C:N ratio (5.4) indicated a marine hemipelagic deposition. The TP was lower at sites near the lower slope (38.4 to 50.0 µmol gv; 0.12% to 0.16%) than those near the channel axis (50.0 to 66 µmol g(-1); 0.15 to 0.21%). C:P fluctuated from 7.7 to 14.1 in the surficial sediment layer. The bulk organic δ13Corg and δ15N values confirmed pelagic organic sources, and the 14C dating revealed that the sediments were deposited during the Holocene (1000-5000 yr BP). We suggest that the hydrodynamic conditions in the Straits influence vertical and advective fluxes of particulate organic material trapped in the mixed-layer, which reduces the particulate matter flux to the seabed.

  9. Assessment of heavy metal pollution in surficial sediments from a tropical river-estuary-shelf system: A case study of Kelantan River, Malaysia.

    Science.gov (United States)

    Wang, Ai-Jun; Bong, Chui Wei; Xu, Yong-Hang; Hassan, Meor Hakif Amir; Ye, Xiang; Bakar, Ahmad Farid Abu; Li, Yun-Hai; Lai, Zhi-Kun; Xu, Jiang; Loh, Kar Hoe

    2017-08-11

    To understand the source-to-sink of pollutants in the Kelantan River estuary and the adjacent shelf area in Malaysia, a total of 42 surface sediment samples were collected in the Kelantan River-estuary-shelf system to analyze for grain size, total organic carbon (TOC) content, Al and heavy metals (Cr, Ni, Cu, Zn, Cd and Pb). The surficial sediments were mainly composed of clayey silt and the TOC content in sediments decreased from the river to the shelf. The surficial sediments experienced Pb pollution; Cr only showed a certain level of pollution in the coastal area of the estuary but not in other areas, and Ni, Cu, Zn, and Cd showed no pollution. The heavy metals mainly originated from natural weathering and erosion of rocks and soils in the catchment and enriched near the river mouth. Total organic carbon can promote the enrichment of heavy metals in sediments. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Trace element distributions in surficial sediments of the northern Tyrrhenian Sea: Contribution to heavy-metal pollution assessment

    Science.gov (United States)

    Leoni, Leonardo; Sartori, Franco; Damiani, Vincenzo; Ferretti, Ornella; Viel, Monique

    1991-03-01

    The trace element distributions in surficial sediment of Tyrrhenian Sea have been investigated as a part of a series of studies on the environmental quality of the area off the Tuscany coast (west-central Italy). This research has focused on the presence of possible contaminated zones; it also provides data for the identification and future monitoring and control of pollution sources. The study of numerous surface sediments and core samples has made it possible to distinguish between heavy-metal enrichments related to natural sources and other anomalies caused by anthropogenic contamination. Over much of the basin, the surface Pb, Cu, Zn, and As contents appear considerably enriched relative to those below 15 cm; among these metals, Pb shows the highest and most widespread enrichment. Only in the case of some coarse-grained sediments close to the mouth of Cecina River it is possible to relate anomalously high Zn contents to natural sources. In all other sampling stations, the enrichments of Pb, Cu, Zn, and As are ascribed to man's influence. The sediment distributions of Co, Cr, and Ni do not seem to be related to anthropogenic activities; rather they mirror influx of materials derived from sources of ophiolitic rock. The distribution of barium shows only two significant positive anomalies, and both are related to natural causes. Concentrations of vanadium are high in a zone close to an important smelting plant; these are thought to be of anthropogenic origin.

  11. Trace element distributions in surficial sediments of the northern Tyrrhenian Sea: Contribution to heavy-metal pollution assessment

    Energy Technology Data Exchange (ETDEWEB)

    Leoni, L.; Sartori, F. (Univ. of Pisa, (Italy)); Damiani, V.; Ferretti, O.; Viel, M. (ENEA, La Spezia (Italy))

    The trace element distributions in surficial sediments of Tyrrhenian Sea have been investigated as a part of a series of studies on the environmental quality of the area off the Tuscany coast (west-central Italy). This research has focused on the presence of possible contaminated zones; it also provides data for the identification and future monitoring and control of pollution sources. The study of numerous surface sediments and core samples has made it possible to distinguish between heavy-metal enrichments related to natural sources and other anomalies caused by anthropogenic contamination. Over much of the basin, the surface Pb, Cu, Zn, and As contents appear considerably enriched relative to the those below 15 cm; among these metals. Pb shows the highest and most widespread enrichment. Only in the case of some coarse-grained sediments close to the mouth of Cecina River it is possible to relate anomalously high Zn contents to natural sources. In all other sampling stations, the enrichments of Pb, Cu, Zn, and As are ascribed to man's influence. The sediment distributions of Co, Cr, and Ni do not seem to be related to anthropogenic activities; rather they mirror influx of materials derived from sources of ophiolitic rock. The distribution of barium shows only two significant positive anomalies, and both are related to natural causes. Concentrations of vanadium are high in a zone close to an important smelting plant; these are thought to be of anthropogenic origin.

  12. Verdine and glaucony facies from surficial sediments of the eastern continental margin of India

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, V.P.; Thamban, M.; Lamboy, M.

    The present paper reports the first mineralogical description of green grains (verdine and glaucony) from sediments of the eastern continental margin of India. Only 24 of the 82 sediment samples studied, at depths between 18 and 247 m, contain green...

  13. Shear-wave velocity of surficial geologic sediments in Northern California: Statistical distributions and depth dependence

    Science.gov (United States)

    Holzer, T.L.; Bennett, M.J.; Noce, T.E.; Tinsley, J. C.

    2005-01-01

    Shear-wave velocities of shallow surficial geologic units were measured at 210 sites in a 140-km2 area in the greater Oakland, California, area near the margin of San Francisco Bay. Differences between average values of shear-wave velocity for each geologic unit computed by alternative approaches were in general smaller than the observed variability. Averages estimated by arithmetic mean, geometric mean, and slowness differed by 1 to 8%, while coefficients of variation ranged from 14 to 25%. With the exception of the younger Bay mud that underlies San Francisco Bay, velocities of the geologic units are approximately constant with depth. This suggests that shear-wave velocities measured at different depths in these surficial geologic units do not need to be normalized to account for overburden stress in order to compute average values. The depth dependence of the velocity of the younger Bay mud most likely is caused by consolidation. Velocities of each geologic unit are consistent with a normal statistical distribution. Average values increase with geologic age, as has been previously reported. Velocities below the water table are about 7% less than those above it. ?? 2005, Earthquake Engineering Research Institute.

  14. Effect of Interaction of Non-residual Fractions on Adsorption of Atrazine onto Surficial Sediments and Natural Surface Coating Samples

    Institute of Scientific and Technical Information of China (English)

    LI Yu; LI Shan-shan; GAO Qian; WANG Ao

    2011-01-01

    To quantify the effect of the interaction of non-residual fractions[Fe oxides(Fe), Mn oxide(Mn), organic materials(OMs)] in the surficial sediments and the natural surface coating samples on the adsorption of atrazine(AT),an AT multiple regression adsorption modeI(AT-MRAM) was developed. The AT-MRAM improves upon the previous AT additional adsorption modeI(AT-AAM) with superior goodness-of-fit test(adjusted R2=ca.l.000), F-test and t-test(P<0.01), and reveals the effect of the interaction among the components in the surficial sediments(SSs) and natural surface coatings samples(NSCSs) on the adsorption of AT, which was neglected by the AT-AAM. Meanwhile, the AT-MRAM was also verified through adsorption experiments of AT and the relative deviation between predicted maximum adsorption of AT and the experimental one is less than 15%. The resulted information shows that Mn is prone to interact with other non-residual components, the total maximum adsorption of AT is inversly proportional to the level of Mn, and Fe and OMs facilitate the adsorption of AT. The results also indicate that the adsorption of AT is not only dominated by Fe, OMs, Fe/OMs, but also restrained by Fe/Mn, Fe/Mn/OMs, with lesser roles attributed to Mn, and the estimated AT distributions among the components do not agree with that previously predicted by the AT-AAM, especially with the relative contribution of Mn to the adsorption of AT, revealing significant contribution of the interactions among non-residual components in controlling the behavior of AT in aquatic environments.

  15. Comparing surficial sediments maps interpreted by experts with dual-frequency acoustic backscatter on the Scotian Shelf, Canada

    Science.gov (United States)

    Cuff, Andrew; Anderson, John T.; Devillers, Rodolphe

    2015-11-01

    Understanding seabed properties is increasingly important to support policy in the marine environment. Such knowledge can be gained from diverse methods, ranging from more traditional expert-interpretations of acoustic and ground-truth data, to maps resulting from fully quantitative analyses of acoustic data. This study directly compares surficial geology maps created through expert-interpretations to near-nadir acoustic backscatter data from two frequencies (38 kHz and 120 kHz) collected using single beam echosounders (SBES) for two 5×1 km study areas on the Scotian Shelf, Canada. Statistical methods were used to analyze and classify both single and dual-frequency acoustic backscatter for comparisons. In particular, spatial scaling of acoustic backscatter responses and acoustic classes created using acoustic seabed classification (ASC) is compared between frequencies and to interpreted sediment units (ISUs) which make up surficial geology maps produced by experts. Seabed morphology layers were included in an ASC approach to reflect the morphological components included in the interpreted geological maps. Results confirmed that higher frequencies and coarser grain sizes generally produced higher backscatter, while more heterogeneous and rougher seabeds produced variable backscatter. Differing acoustic responses within similar substrate units suggest fundamental seabed variations not reflected in the geological interpretations. Spatial scaling of sand and gravel substrates from 38 kHz frequency were closer than the 120 kHz frequency to the spatial scaling of the interpreted geological map. Variable grain size in the sediment volume and surface morphology are both presented as possible reasons for frequency differences. While both frequencies had similar general responses, differences in frequency responses of backscatter occurred at scales of tens to hundreds of meters. Results presented here emphasize the importance of multi-scale seabed mapping and additional

  16. Wetland Paleoecological Study of Coastal Louisiana: Surface Sediment and Diatom Calibration Dataset

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Wetland sediment data was collected from coastal Louisiana as part of a pilot study to develop a diatom-based proxy for past wetland water chemistry and the...

  17. Wetland Paleoecological Study of Coastal Louisiana: Sediment Cores and Diatom Samples Dataset

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Wetland sediment data was collected from coastal Louisiana as part of a pilot study to develop a diatom-based proxy for past wetland water chemistry and the...

  18. Wetland Paleoecological Study of Coastal Louisiana: Sediment Cores and Diatom Samples Dataset

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Wetland sediment data was collected from coastal Louisiana as part of a pilot study to develop a diatom-based proxy for past wetland water chemistry and the...

  19. Wetland Paleoecological Study of Coastal Louisiana: Surface Sediment and Diatom Calibration Dataset

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Wetland sediment data was collected from coastal Louisiana as part of a pilot study to develop a diatom-based proxy for past wetland water chemistry and the...

  20. Effects of sediment removal on vegetation communities in Rainwater Basin playa wetlands.

    Science.gov (United States)

    Beas, Benjamin J; Smith, Loren M; LaGrange, Theodore G; Stutheit, Randy

    2013-10-15

    Sedimentation from cultivated agricultural land use has altered the natural hydrologic regimes of depressional wetlands in the Great Plains. These alterations can negatively affect native wetland plant communities. Our objective was to determine if restored wetlands are developing plant communities similar to reference wetland conditions following hydrologic restoration. For this study, hydrology was restored via sediment removal. Thirty-four playa wetlands in reference, restored, and agricultural condition within the Rainwater Basin Region of Nebraska were sampled in 2008 and 2009. In 2008, reference and restored wetlands had higher species richness and more native, annual, and perennial species than agricultural wetlands. Restored wetlands had similar exotic species richness compared to reference and agricultural wetlands; however, reference wetlands contained more than agricultural wetlands. Restored wetlands proportion of exotics was 3.5 and 2 times less than agricultural wetlands and reference wetlands respectively. In 2009, reference and restored wetlands had higher species richness, more perennial species, and more native species than agricultural wetlands. Restored wetlands contained a greater number and proportion of annuals than reference and agricultural wetlands. Canonical Correspondence Analysis showed that reference, restored, and agricultural wetlands are dominated by different plant species and guilds. Restored wetland plant communities do not appear to be acting as intermediates between reference and agricultural wetland conditions or on a trajectory to reach reference conditions. This may be attributed to differing seed bank communities between reference and restored wetlands, dispersal limitations of perennial plant guilds associated with reference wetland conditions, and/or management activities may be preventing restored wetlands from reaching reference status. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Heavy metals in surficial sediments of the central Bohai Sea:their distribution, speciation and sources

    Institute of Scientific and Technical Information of China (English)

    LIU Ming; FAN Dejiang; LIAO Yongjie; CHEN Bin; YANG Zuosheng

    2016-01-01

    The semi-enclosed Bohai Sea has received large amount of pollutants from surrounding rivers and sewage channels along the densely populated and industrializing Bohai coasts, as well as the offshore oil exploration in the sea. The concentrations of heavy metals copper, cobalt, nickel, zinc, lead, chromium and cadmium in 25 surface sediment samples from the central Bohai Sea are obtained by ICP-MS analysis. The speciation of these heavy metals is extracted and their distribution, fractionation, pollution status and sources are presented. High concentrations of copper, cobalt, nickel, zinc and chromium are found in the sediments off the coastal area of the Bohai Bay and the central Bohai Sea mud, while high concentrations of cadmium and lead are found in the sediments in the whole study area. The residual fraction is the dominant form of copper, cobalt, nickel, zinc and chromium in the surface sediments, while cadmium and lead have large proportions in the nonresidual fractions. The ecological risk assessment shows that the sediments in the study area are unpolluted with respect to the heavy metals of cobalt, nickel and chromium and unpolluted to moderately polluted with respect to copper, zinc, cadmium and lead. Cobalt, nickel and chromium mainly have natural origin and their concentrations significantly vary with the composition of the sediments. The contents of copper, zinc, lead and especially cadmium in sediments are suggested to be influenced by pollutants of human activities. The heavy metals in the surface sediments at most sampling stations are mainly come from the Huanghe River; the heavy metals in the sediments in the northernmost part of the study area are significantly affected by the sediment from the Luanhe River; while in the Bohai Bay and the central region they were affected by the sediment from the Haihe River and aerosol deposition.

  2. Surficial geology and distribution of post-impoundment sediment in Las Vegas Bay, Lake Mead

    Science.gov (United States)

    Twichell, David C.; Cross, VeeAnn A.; Rudin, Mark J.; Parolski, Kenneth F.; Rendigs, Richard R.

    2001-01-01

    Sidescan sonar imagery and seismic-reflection profiles were collected in the northwestern part of Las Vegas Bay to map the distribution and volume of sediment that has accumulated in this part of Lake Mead since impoundment. The mapping suggests that three ephemeral streams are the primary source of this sediment, and of these, Las Vegas Wash is the largest. Two deltas off the mouth of Las Vegas Wash formed at different lake elevations and account for 41% of the total volume of post-impoundment sediment within the study area. Deltas off the other two washes (Gypsum and Government) account for only 6% of the total volume. The sediment beyond the front of the deltas is primarily mud, and it only occurs in valley floors, where it forms a flat-lying blanket that is mostly less than 1.5 m thick. Although a thin layer, the fine-grained sediment accounts for approximately 53% of the total post-impoundment sediment volume of 5.7 x 106 m3 that has accumulated in the study area. This sediment appears to have been transported several kilometers from the river sources by density flows.

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

    Science.gov (United States)

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

    2012-01-01

    Concentrations and distributions of trace metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in surficial sediments of the Cochin backwaters were studied during both monsoon and pre-monsoon periods. Spatial variations were in accordance with textural charaterstics and organic matter content. A principal component analysis distinguished three zones with different metal accumulation capacity: (i) highest levels in north estuary, (ii) moderate levels in central zone, and (iii) lowest levels in southern part. Trace metal enrichments are mainly due to anthropogenic contribution of industrial, domestic, and agricultural effluents, whose effect is enhanced by settling of metals due to organic flocculation and inorganic precipitation associated with salinity changes. Enrichments factors using Fe as a normalizer showed that metal contamination was the product of anthropogenic activities. An assessment of degree of pollution-categorized sediments as moderately polluted with Cu and Pb, moderately-to-heavily polluted with Zn, and heavily-to-extremely polluted with Cd. Concentrations at many sites largely exceed NOAA ERL (e.g., Cu, Cr, and Pb) or ERM (e.g., Cd, Ni, and Zn). This means that adverse effects for benthic organisms are possible or even highly probable. PMID:22645488

  4. Total and methyl mercury, moisture, and porosity in Lake Michigan surficial sediment

    Data.gov (United States)

    U.S. Environmental Protection Agency — Total and methyl mercury, moisture content (%), and porosity were measured in Lake Michigan sediment by the U.S. Environmental Protection Agency/Office of Research...

  5. USGS Map service: usSEABED - US Coastal Offshore Surficial-Sediment

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The usSEABED database contains a compilation of published and previously unpublished sediment texture and other geologic data about the sea floor from diverse...

  6. Planktonic organic matter in surficial sediments of the Banda Sea (Indonesia) : a palynological approach

    NARCIS (Netherlands)

    van Waveren, I.M.

    1993-01-01

    The acid resistant microscopic organic matter preserved in marine sediments (palynofacies) represents a small fraction of marine and terrestrial biomass that escaped rapid degradation and recycling to the atmospheric and hydrospheric carbon reservoirs. Palynofacies consists of (1) organic

  7. USGS Map service: usSEABED - US Coastal Offshore Surficial-Sediment

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The usSEABED database contains a compilation of published and previously unpublished sediment texture and other geologic data about the sea floor from diverse...

  8. Thickness of the surficial aquifer, Delmarva Peninsula, Maryland and Delaware

    Science.gov (United States)

    Denver, Judith; Nardi, Mark R.

    2017-01-01

    A digital map of the thickness of the surficial unconfined aquifer, including from the land surface and unsaturated zone to the bottom of sediments of geologic units identified as part of the surficial aquifer, was produced to improve understanding of the hydrologic system in the Maryland and Delaware portions of the Delmarva Peninsula. The map is intended to be used in conjunction with other environmental coverages (such land use, wetlands, and soil characteristics) to provide a subsurface hydrogeologic component to studies of nitrate transport that have historically relied on maps of surficial features. It could also be used to study the transport of other water soluble chemicals. The map was made using the best currently available data, which was of varying scales. It was created by overlaying a high resolution land surface and bathymetry digital elevation model (DEM) on a digital representation of the base of the surficial aquifer, part of hydrogeologic framework, as defined by Andreasen and others (2013). Thickness was calculated as the difference between the top of land surface and the bottom of the surficial aquifer sediments, which include sediments from geologic formations of late-Miocene through Quaternary age. Geologic formations with predominantly sandy surficial sediments that comprise the surficial aquifer on the Delmarva Peninsula include the Parsonsburg Sand, Sinepuxent Formation (Fm.), and parts of the Omar Fm. north of Indian River Bay in Delaware, the Columbia Fm., Beaverdam Fm., and Pennsauken Fm. (Ator and others 2005; Owens and Denney, 1986; Mixon, 1985; Bachman and Wilson, 1984). Formations with mixed texture and sandy stratigraphy including the Scotts Corner Fm. and Lynch Heights Fm. in Delaware are also considered part of the surficial aquifer (Ramsey, 1997). Subcropping aquifers and confining beds underlie the surficial aquifer throughout the Peninsula and may increase or limit its thickness, respectively (Andreasen and others, 2013

  9. Contribution of recent hurricanes to wetland sedimentation in coastal Louisiana

    Science.gov (United States)

    Liu, Kam-biu; Bianchette, Thomas; Zou, Lei; Qiang, Yi; Lam, Nina

    2017-04-01

    Hurricanes are important agents of sediment deposition in the wetlands of coastal Louisiana. Since Hurricanes Katrina and Rita of 2005, coastal Louisiana has been impacted by Hurricanes Gustav (2008), Ike (2008), and Isaac (2012). By employing the principles and methods of paleotempestology we have identified the storm deposits attributed to the three most recent hurricanes in several coastal lakes and swamps in Louisiana. However, the spatial distribution and volume of these storm depositions cannot be easily inferred from stratigraphic data derived from a few locations. Here we report on results from a GIS study to analyze the spatial and temporal patterns of storm deposition based on data extracted from the voluminous CRMS (Coastal Reference Monitoring System) database, which contains vertical accretion rate measurements obtained from 390 wetland sites over various time intervals during the past decade. Wetland accretion rates averaged about 2.89 cm/yr from stations sampled before Hurricane Isaac, 4.04 cm/yr during the 7-month period encompassing Isaac, and 2.38 cm/yr from sites established and sampled after Isaac. Generally, the wetland accretion rates attributable to the Isaac effects were 40% and 70% greater than before and after the event, respectively. Accretion rates associated with Isaac were highest at wetland sites along the Mississippi River and its tributaries instead of along the path of the hurricane, suggesting that freshwater flooding from fluvial channels, enhanced by the storm surge from the sea, is the main mechanism responsible for increased accretion in the wetlands. Our GIS work has recently been expanded to include other recent hurricanes. Preliminary results indicate that, for non-storm periods, the average wetland accretion rates between Katrina/Rita and Gustav/Ike was 2.58 cm/yr; that between Gustav/Ike and Isaac was 1.95 cm/yr; and that after Isaac was 2.37 cm/yr. In contrast, the accretion rates attributable to the effects of Gustav

  10. Geochemistry of surficial sediments along the central southwest coast of India - Seasonal changes in regional distribution

    Digital Repository Service at National Institute of Oceanography (India)

    Balachandran, K.K.; Joseph, T.; Nair, M.; Sankaranarayanan, V.N.; Das, V.K.; Sheeba, P.

    carbon of the composite samples using wet digestion (chromic acid) followed by back titration with ferrous ammonium sulphate (EL WAKEEL and RILEY, 1957, precision::':: 0.25%). Finely powdered and dried (at 105 0 ::':: 5°C) sediments were digested in a...-earth element;; in the fluvial fraction « 4 IJ-m) that also date back to one~ct of sampling during 1981. Inadequacies in all the above stud ies have been their proper addressing of the influence 'If Seasonal Analysis of Sediment Geochemistry 665 Legend: PALL...

  11. Application of ecological risk indicators for the assessment of Greek surficial sediments contaminated by toxic metals.

    Science.gov (United States)

    Hahladakis, John Ν; Vasilaki, Georgia; Smaragdaki, Eleftheria; Gidarakos, Evangelos

    2016-05-01

    Τhe present research investigates the partitioning of six selected toxic metals (Ni, Cr, Pb, Zn, Cu, and As) in eight sediment samples; half of them were collected from Elefsis Gulf, and the other half were taken from Koumoundourou Lake, Athens, Greece. Each one of them was treated by applying Tessier's five-step sequential extraction procedure. Regarding gulf sediments, the results indicated that Cu exhibits a strong affinity to the organic matter with percentages ranging from 65 to 78 %. Considerable amount of Zn (32-40 %) is bound to the Fe-Mn fraction and the non-residual fraction, while Cr and Ni are bound to the organic fraction, an observation that suits all toxic metals examined. Regarding lake sediments, Pb is the predominant metal bound to Fe-Mn (48-51 %). It is also noteworthy that the percentage of Zn bound to carbonated fraction (5-15 %), indicating biological availability. In conclusion, the application of several ecological risk indicators demonstrated that Elefsis Gulf sediments correspond to a moderate pollution level, with Pb and Ni being less bioavailable than in the lake's samples, in contrast to Zn which is more bioavailable. Finally, Koumoundourou Lakes' basin is characterized of "low risk."

  12. Biogeochemistry of the surficial sediments of the western and eastern continental shelves of India

    Digital Repository Service at National Institute of Oceanography (India)

    Jacob, J.; Chandramohanakumar, N.; Jayaraj, K.A.; Raveendran, T.V.; Balachandran, K.K.; Joseph, T.; Nair, M.; Achuthankutty, C.T.; Nair, K.K.C.; George, R.; Ravi, Z.P.

    compared to the east coast, but the percentages of labile constituents of total organic matter in the sediments were found to be higher in the east coast by a factor of three as compared to the west coast. The differences in the productivity patterns...

  13. Rare earth element studies of surficial sediments from the southwestern Carlsberg Ridge, Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Pattan, J.N; Higgs, N

    into these sediments is suggested from the weak positive Eu/Eu anomaly. Shale-normalized (NASC) pattern along with La sub((n)/Yb sub((n) ratio suggest enrichment of heavy REE (HREE) relative to the light REE (LREE) with a negative Ce/Ce anomaly implying retention of a...

  14. Distinct Bacterial Communities in Surficial Seafloor Sediments Following the 2010 Deepwater Horizon Blowout

    DEFF Research Database (Denmark)

    Yang, Tingting; Speare, Kelly; McKay, Luke

    2016-01-01

    A major fraction of the petroleum hydrocarbons discharged during the 2010 Macondo oil spill became associated with and sank to the seafloor as marine snow flocs. This sedimentation pulse induced the development of distinct bacterial communities. Between May 2010 and July 2011, full-length 16S rRN...

  15. Water- and air-quality and surficial bed-sediment monitoring of the Sweetwater Reservoir watershed, San Diego County, California, 2003-09

    Science.gov (United States)

    Mendez, Gregory O.; Majewski, Michael S.; Foreman, William T.; Morita, Andrew Y.

    2015-01-01

    In 1998, the U.S. Geological Survey, in cooperation with the Sweetwater Authority, began a study to assess the overall health of the Sweetwater watershed in San Diego County, California. This study was designed to provide a data set that could be used to evaluate potential effects from the construction and operation of State Route 125 within the broader context of the water quality and air quality in the watershed. The study included regular sampling of water, air, and surficial bed sediment at Sweetwater Reservoir (SWR) for chemical constituents, including volatile organic compounds (VOCs), base-neutral and acid- extractable organic compounds (BNAs) that include polycyclic aromatic hydrocarbons (PAHs), pesticides, and metals. Additionally, water samples were collected for anthropogenic organic indicator compounds in and around SWR. Background water samples were collected at Loveland Reservoir for VOCs, BNAs, pesticides, and metals. Surficial bed-sediment samples were collected for PAHs, organochlorine pesticides, and metals at Sweetwater and Loveland Reservoirs.

  16. Adsorption of multi-heavy metals Zn and Cu onto surficial sediments: modeling and adsorption capacity analysis.

    Science.gov (United States)

    Li, Shanshan; Zhang, Chen; Wang, Meng; Li, Yu

    2014-01-01

    Improved multiple regression adsorption models (IMRAMs) was developed to estimate the adsorption capacity of the components [Fe oxides (Fe), Mn oxides (Mn), organic materials (OMs), residuals] in surficial sediments for multi-heavy metal Zn and Cu. IMRAM is an improved version over MRAM, which introduces a computer program in the model developing process. As MRAM, Zn(Cu) IMRAM, and Cu(Zn) IMRAM again confirmed that there is significant interaction effects that control the adsorption of compounded Zn and Cu, which was neglected by additional adsorption model. The verification experiment shows that the relative deviation of the IMRAMs is less than 13%. It is revealed by the IMRAMs that Mn, which has the greatest adsorption capability for compounded Zn and Cu (54.889 and 161.180 mg/l, respectively), follows by interference adsorption capacity of Fe/Mn (-1.072 and -24.591 mg/l respectively). Zn and Cu influence each other through different mechanisms. When Zn is the adsorbate, compounded Cu mainly affects the adsorption capacities of Fe/Mn and Fe/Mn/OMs; while when Cu is the adsorbate, compounded Zn mainly exerts its effect on Mn, Fe/Mn, and Mn/OMs. It also shows that the compounded Zn or Cu weakened the interference adsorption of Fe/Mn, and meanwhile, strengthened the interference adsorption of Mn/OMs.

  17. Distribution of mercury in surficial sediments from Todos Santos Bay, Baja California, México.

    Science.gov (United States)

    Gutiérrez-Galindo, E A; Casas-Beltrán, D A; Muñoz-Barbosa, A; Daesslé, L W; Segovia-Zavala, J A; Macías-Zamora, J V; Orozco-Borbón, M V

    2008-02-01

    During 2004 the spatial distribution of total Hg in sediments from Todos Santos Bay, Baja California, México was studied to evaluate the degree of environmental impact in this bay. The results showed low concentrations and no Hg enrichment at any site. These findings suggest natural levels of Hg in the water of Todos Santos Bay. The regional distribution of Hg/Fe shows lower values in the East and higher in the West of the bay. No significant correlations (p<0.05) were found between Hg and organic matter or particle size, suggesting that the distribution of Hg is not controlled by these variables.

  18. Efficacy of natural wetlands to retain nutrient, sediment and microbial pollutants.

    Science.gov (United States)

    Knox, A K; Dahlgren, R A; Tate, K W; Atwill, E R

    2008-01-01

    Wetlands can improve water quality through natural processes including sedimentation, nutrient transformations, and microbial and plant uptake. Tailwater from irrigated pastures may contribute to nonpoint source water pollution in the form of sediments, nutrients, and pathogens that degrade downstream water quality. We examined benefits to water quality provided by a natural, flow-through wetland and a degraded, channelized wetland situated within the flood-irrigation agricultural landscape of the Sierra Nevada foothills of Northern California. The non-degraded, reference wetland significantly improved water quality by reducing loads of total suspended sediments, nitrate, and Escherichia coli on average by 77, 60, and 68%, respectively. Retention of total N, total P, and soluble reactive P (SRP) was between 35 and 42% of loads entering the reference wetland. Retention of pollutant loads by the channelized wetland was significantly lower than by the reference wetland for all pollutants except SRP. A net export of sediment and nitrate was observed from the channelized wetland. Decreased irrigation inflow rates significantly improved retention efficiencies for nitrate, E. coli, and sediments in the reference wetland. We suggest that maintenance of these natural wetlands and regulation of inflow rates can be important aspects of a best management plan to improve water quality as water runs off of irrigated pastures.

  19. Sediment accumulation in prairie wetlands under a changing climate: The relative roles of landscape and precipitation

    Science.gov (United States)

    Skagen, Susan; Burris, Lucy E.; Granfors, D.A.

    2016-01-01

    Sediment accumulation threatens the viability and hydrologic functioning of many naturally formed depressional wetlands across the interior regions of North America. These wetlands provide many ecosystem services and vital habitats for diverse plant and animal communities. Climate change may further impact sediment accumulation rates in the context of current land use patterns. We estimated sediment accretion in wetlands within a region renowned for its large populations of breeding waterfowl and migrant shorebirds and examined the relative roles of precipitation and land use context in the sedimentation process. We modeled rates of sediment accumulation from 1971 through 2100 using the Revised Universal Soil Loss Equation (RUSLE) with a sediment delivery ratio and the Unit Stream Power Erosion Deposition model (USPED). These models predicted that by 2100, 21–33 % of wetlands filled completely with sediment and 27–46 % filled by half with sediments; estimates are consistent with measured sediment accumulation rates in the region reported by empirical studies. Sediment accumulation rates were strongly influenced by size of the catchment, greater coverage of tilled landscape within the catchment, and steeper slopes. Conservation efforts that incorporate the relative risk of infilling of wetlands with sediments, thus emphasizing areas of high topographic relief and large watersheds, may benefit wetland-dependent biota.

  20. n-Alkanes in surficial sediments of Visakhapatnam harbour, east coast of India

    Science.gov (United States)

    Punyu, V. R.; Harji, R. R.; Bhosle, N. B.; Sawant, S. S.; Venkat, K.

    2013-04-01

    Surface sediments collected from 19 stations along Visakhapatnam harbour were analysed for organic carbon (OC), δ 13Coc, total lipids (TL), total hydrocarbon (THC), n-alkane concentration and composition. OC, δ 13Coc, TL and THC ranged from 0.6% to 7.6%, -29.3 to -23.8‰, 300 to 14,948 \\upmu g g - 1 dw, and 0.2 to 2,277 \\upmu g g - 1 dw, respectively. Predominance of even carbon numbers n-alkanes C12-C21 with carbon preference index (CPI) of <1 suggests major microbial influence. Fair abundance of odd carbon number n-alkanes in the range of C15-C22 and C23-C33 indicates some input from phytoplankton and terrestrial sources, respectively. Petrogenic input was evident from the presence of hopanes and steranes. The data suggest that organic matter (OM) sources varied spatially and were mostly derived from mixed source.

  1. -Alkanes in surficial sediments of Visakhapatnam harbour, east coast of India

    Indian Academy of Sciences (India)

    V R Punyu; R R Harji; N B Bhosle; S S Sawant; K Venkat

    2013-04-01

    Surface sediments collected from 19 stations along Visakhapatnam harbour were analysed for organic carbon (OC), 13CoC, total lipids (TL), total hydrocarbon (THC), -alkane concentration and composition. OC, 13CoC, TL and THC ranged from 0.6% to 7.6%, -29.3 to -23.8‰, 300 to 14,948 g g−1 dw, and 0.2 to 2,277 g g−1 dw, respectively. Predominance of even carbon numbers -alkanes C12–C21 with carbon preference index (CPI) of < 1 suggests major microbial influence. Fair abundance of odd carbon number -alkanes in the range of C15–C22 and C23–C33 indicates some input from phytoplankton and terrestrial sources, respectively. Petrogenic input was evident from the presence of hopanes and steranes. The data suggest that organic matter (OM) sources varied spatially and were mostly derived from mixed source.

  2. Mud On the Move: Measuring Suspended Sediment Concentrations within Tidal Wetlands in the San Francisco Estuary

    Science.gov (United States)

    Callaway, J.; Ferner, M.; Lacy, J. R.; Schile, L. M.

    2014-12-01

    Supply of suspended sediment is critical for the development and sustainability of tidal wetlands. Suspended sediment concentration (SSC) is also a key parameter used in calibrating wetland accretion models, which aid in understanding restoration dynamics and projecting resilience to sea-level rise. Despite the importance of suspended sediment, few field studies have directly measured SSC within tidal wetlands, relying instead on measurements in adjacent waters or focusing on long-term rates of sediment accretion. We refined and tested a simple method for collecting SSC samples within wetlands on an incoming high tide, using siphon collectors. Bottles were positioned during low tide at set locations along transects extending away from either channels or the lower boundary of the vegetated wetland. This sampling protocol was developed collaboratively, with substantial input from local wetland managers and other stakeholders within the San Francisco Bay area and beyond. Simultaneously, we measured time series of SSC, water level, and tidal currents in the subtidal shallows, on the intertidal mudflats, and in two channels within the wetland. We observed significant sediment export during king tides in the wetland channels. Cumulative suspended sediment flux (SSF) over four days during the January 2014 king tides was approximately 10 tons/m of channel width, towards the bay. During neap tides SSF in the channels was directed landward but was lower in magnitude. Elevated velocities in the channels during ebb king tides suggest that resuspension within the channels, rather than erosion of the wetland, accounts for much of the bayward SSF. Within the wetland, SSC from the siphon samplers was highest at the bayward end of the cross-shore transects, indicating landward sediment flux. Taken together with long term accretion data which indicates sediment accumulation within the wetland, our results suggest that sediment is primarily supplied across the wetland-Bay interface

  3. Surficial sediment character of the New York-New Jersey offshore continental shelf region: a GIS compilation

    Science.gov (United States)

    Williams, S. Jeffress; Arsenault, Matthew A.; Poppe, Lawrence J.; Reid, Jane A.; Reid, Jamey M.; Jenkins, Chris J.

    2007-01-01

    Broad continental shelf regions such as the New York Bight are the product of a complex geologic history and dynamic oceanographic processes, dominated by the Holocene marine transgression (>100 m sea-level rise) following the end of the last Pleistocene ice advance ~ 20,000 years ago. The area of the U.S. Exclusive Economic Zone (U.S. EEZ) territory, extending 200 nautical miles seaward from the coast, is larger than the continental U.S. and contains submerged landforms that provide a variety of natural functions and societal benefits, such as: critical habitats for fisheries, ship navigation and homeland security, and engineering activities (i.e. oil and gas platforms, pipeline and cable routes, potential wind-energy-generation sites). Some parts of the continental margins, particularly inner-continental shelf regions, also contain unconsolidated hard-mineral deposits such as sand and gravel that are regarded as potential aggregate resources to meet or augment needs not met by onshore deposits (Williams, 1992). The present distribution of surficial sediment off the northeastern United States is shaped from the deposits left by the last glaciation and reflects the cumulative effects of sediment erosion, transport, sorting, and deposition by storm and tidal processes during the Holocene rise in sea level. As a result, the sediments on the sea floor represent both an historical record of former conditions and a guide to possible future sedimentary environments. The U.S. Geological Survey (USGS) through the Coastal and Marine Geology Program, in cooperation with the University of Colorado and other partners, has compiled extant sediment character and textural data as well as other geologic information on the sea floor from all regions around the U.S. into the usSEABED data system (Reid and others, 2005; Buczkowski and others, 2006; Reid and others, 2006). The usSEABED system, which contains information on sediment grain size and lithology for more than 340

  4. Distribution of Surficial Sediments of NOAA H11310 Sidescan Sonar Mosaic in Central Narragansett Bay (H11310SEDS.SHP)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The United States Geological Survey (USGS) is working cooperatively with the National Oceanic and Atmospheric Association (NOAA) to interpret the surficial geology...

  5. Anthropogenic acceleration of sediment accretion in lowland floodplain wetlands, Murray-Darling Basin, Australia

    Science.gov (United States)

    Gell, Peter; Fluin, Jennie; Tibby, John; Hancock, Gary; Harrison, Jennifer; Zawadzki, Atun; Haynes, Deborah; Khanum, Syeda; Little, Fiona; Walsh, Brendan

    2009-07-01

    Over the last decade there has been a deliberate focus on the application of paleolimnological research to address issues of sediment flux and water quality change in the wetlands of the Murray-Darling Basin of Australia. This paper reports on the research outcomes on cores collected from sixteen wetlands along the Murrumbidgee-Murray River continuum. In all sixteen wetlands radiometric techniques and exotic pollen biomarkers were used to establish sedimentation rates from the collected cores. Fossil diatom assemblages were used to identify water source and quality changes to the wetlands. The sedimentation rates of all wetlands accelerated after European settlement, as little as two-fold, and as much as eighty times the mean rate through the Late Holocene. Some wetlands completely infilled through the Holocene, while others have rapidly progressed towards a terrestrial state due to accelerated accretion rates. Increasing wetland salinity and turbidity commenced within decades of settlement, contributing to sediment inputs. The sedimentation rate was observed to slow after river regulation in one wetland, but has accelerated recently in others. The complex history of flooding and drying, and wetland salinisation and eutrophication, influence the reliability of models used to establish recent, fine-resolution chronologies with confidence and the capacity to attribute causes to documented effects.

  6. Wetland paleoecological study of southwest coastal Louisiana: sediment cores and diatom calibration dataset

    Science.gov (United States)

    Smith, Kathryn E. L.; Flocks, James G.; Steyer, Gregory D.; Piazza, Sarai C.

    2015-01-01

    Wetland sediment data were collected in 2009 and 2010 throughout the southwest Louisiana Chenier Plain as part of a pilot study to develop a diatom-based proxy for past wetland water chemistry and the identification of sediment deposits from tropical storms. The complete dataset includes forty-six surface sediment samples and nine sediment cores. The surface sediment samples were collected in fresh, intermediate, and brackish marsh and are located coincident with Coastwide Reference Monitoring System (CRMS) sites. The nine sediment cores were collected at the Rockefeller Wildlife Refuge (RWR) located in Grand Chenier, La.

  7. Methylmercury in water, sediment, and invertebrates in created wetlands of Rouge Park, Toronto, Canada.

    Science.gov (United States)

    Sinclair, Kathleen A; Xie, Qun; Mitchell, Carl P J

    2012-12-01

    Thousands of hectares of wetlands are created annually because wetlands provide beneficial ecosystem services. Wetlands are also key sites for production of the bioaccumulative neurotoxin methylmercury (MeHg), but little is known about MeHg production in created systems. Here, we studied methylmercury in sediment, water, and invertebrates in created wetlands of various ages. Sediment MeHg reached 8 ng g(-1) in the newest wetland, which was significantly greater than in natural, control wetlands. This trend was mirrored in several invertebrate taxa, whose concentrations reached as high as 1.6 μg g(-1) in the newest wetland, above levels thought to affect reproduction in birds. The MeHg concentrations in created wetland invertebrate taxa generally decreased with increasing wetland age, possibly due to a combination of deeper anoxia and less organic matter accumulation in younger wetlands. A short-term management intervention and/or improved engineering design may be necessary to reduce the mercury-associated risk in newly created wetlands.

  8. Landscape-scale analysis of wetland sediment deposition from four tropical cyclone events.

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    Andrew W Tweel

    Full Text Available Hurricanes Katrina, Rita, Gustav, and Ike deposited large quantities of sediment on coastal wetlands after making landfall in the northern Gulf of Mexico. We sampled sediments deposited on the wetland surface throughout the entire Louisiana and Texas depositional surfaces of Hurricanes Katrina, Rita, Gustav, and the Louisiana portion of Hurricane Ike. We used spatial interpolation to model the total amount and spatial distribution of inorganic sediment deposition from each storm. The sediment deposition on coastal wetlands was an estimated 68, 48, and 21 million metric tons from Hurricanes Katrina, Rita, and Gustav, respectively. The spatial distribution decreased in a similar manner with distance from the coast for all hurricanes, but the relationship with distance from the storm track was more variable between events. The southeast-facing Breton Sound estuary had significant storm-derived sediment deposition west of the storm track, whereas sediment deposition along the south-facing coastline occurred primarily east of the storm track. Sediment organic content, bulk density, and grain size also decreased significantly with distance from the coast, but were also more variable with respect to distance from the track. On average, eighty percent of the mineral deposition occurred within 20 km from the coast, and 58% was within 50 km of the track. These results highlight an important link between tropical cyclone events and coastal wetland sedimentation, and are useful in identifying a more complete sediment budget for coastal wetland soils.

  9. Landscape-scale analysis of wetland sediment deposition from four tropical cyclone events.

    Science.gov (United States)

    Tweel, Andrew W; Turner, R Eugene

    2012-01-01

    Hurricanes Katrina, Rita, Gustav, and Ike deposited large quantities of sediment on coastal wetlands after making landfall in the northern Gulf of Mexico. We sampled sediments deposited on the wetland surface throughout the entire Louisiana and Texas depositional surfaces of Hurricanes Katrina, Rita, Gustav, and the Louisiana portion of Hurricane Ike. We used spatial interpolation to model the total amount and spatial distribution of inorganic sediment deposition from each storm. The sediment deposition on coastal wetlands was an estimated 68, 48, and 21 million metric tons from Hurricanes Katrina, Rita, and Gustav, respectively. The spatial distribution decreased in a similar manner with distance from the coast for all hurricanes, but the relationship with distance from the storm track was more variable between events. The southeast-facing Breton Sound estuary had significant storm-derived sediment deposition west of the storm track, whereas sediment deposition along the south-facing coastline occurred primarily east of the storm track. Sediment organic content, bulk density, and grain size also decreased significantly with distance from the coast, but were also more variable with respect to distance from the track. On average, eighty percent of the mineral deposition occurred within 20 km from the coast, and 58% was within 50 km of the track. These results highlight an important link between tropical cyclone events and coastal wetland sedimentation, and are useful in identifying a more complete sediment budget for coastal wetland soils.

  10. Using gas flux to estimate biological and chemical sediment oxygen demand in oil sands-affected wetlands

    Energy Technology Data Exchange (ETDEWEB)

    Gardner Costa, J.; Slama, C.; Ciborowski, J. [Windsor Univ., ON (Canada)

    2010-07-01

    The constituents of oil sands process-affected (OSPM) wetlands include high salinity, conductivity and naphthenic acid concentrations. These constituents are expected to strain microbial communities and change methane and carbon dioxide flux rates as well as sediment oxygen consumption compared to fresher, reference wetland sites. Four OSPM and 4 reference wetlands were examined during the summers of 2009 and 2010 to determine if carbon loss in the form of sediment-associated microbial respiration differs between OSPM and reference wetlands. The study showed that OSPM wetlands release about 10 times less methane than reference wetlands. Sediment oxygen demand (SOD) was measured in 2009 and gas flux estimates of carbon dioxide were used to estimate biological sediment oxygen consumption (BSOC). Chemical sediment oxygen demand (CSOD) was estimated by subtracting BSOC from total SOD. SOD rates were found to be two times higher in OSPM wetlands than reference. CSOD was higher than biologically consumed oxygen for both wetland classes. Although microbial activity in OSPM wetlands may be lower, more oxygen is consumed in OSPM than in reference wetlands. The reclamation of boreal wetlands in the Alberta Athabasca region requires carbon accrual. Less microbial activity may promote carbon accumulation within OSPM wetlands. However, the wetland's sediment layer may have less organic input as a result of high chemical oxygen consumption because it limits benthos respiration.

  11. Linking the historic 2011 Mississippi River flood to coastal wetland sedimentation

    Science.gov (United States)

    Falcini, Federico; Khan, Nicole S.; Macelloni, Leonardo; Horton, Benjamin P.; Lutken, Carol B.; McKee, Karen L.; Santoleri, Rosalia; Colella, Simone; Li, Chunyan; Volpe, Gianluca; D'Emidio, Marco; Salusti, Alessandro; Jerolmack, Douglas J.

    2012-11-01

    Wetlands in the Mississippi River deltaic plain are deteriorating in part because levees and control structures starve them of sediment. In spring 2011 a record-breaking flood brought discharge on the lower Mississippi River to dangerous levels, forcing managers to divert up to 3,500m3s-1 of water to the Atchafalaya River Basin. Here we use field-calibrated satellite data to quantify differences in inundation and sediment-plume patterns between the Mississippi and Atchafalaya River. We assess the impact of these extreme outflows on wetland sedimentation, and use in situ data collected during the historic flood to characterize the Mississippi plume's hydrodynamics and suspended sediment. We show that a focused, high-momentum jet emerged from the leveed Mississippi, and delivered sediment far offshore. In contrast, the plume from the Atchafalaya was more diffuse; diverted water inundated a large area, and sediment was trapped within the coastal current. The largest sedimentation, of up to several centimetres, occurred in the Atchafalaya Basin despite the larger sediment load carried by the Mississippi. Sediment accumulation was lowest along the shoreline between the two river sources. We conclude that river-mouth hydrodynamics and wetland sedimentation patterns are mechanistically linked, providing results that are relevant for plans to restore deltaic wetlands using artificial diversions.

  12. Inferring tidal wetland stability from channel sediment fluxes: observations and a conceptual model

    Science.gov (United States)

    Ganju, Neil K.; Nidzieko, Nicholas J.; Kirwan, Matthew L.

    2013-01-01

    Anthropogenic and climatic forces have modified the geomorphology of tidal wetlands over a range of timescales. Changes in land use, sediment supply, river flow, storminess, and sea level alter the layout of tidal channels, intertidal flats, and marsh plains; these elements define wetland complexes. Diagnostically, measurements of net sediment fluxes through tidal channels are high-temporal resolution, spatially integrated quantities that indicate (1) whether a complex is stable over seasonal timescales and (2) what mechanisms are leading to that state. We estimated sediment fluxes through tidal channels draining wetland complexes on the Blackwater and Transquaking Rivers, Maryland, USA. While the Blackwater complex has experienced decades of degradation and been largely converted to open water, the Transquaking complex has persisted as an expansive, vegetated marsh. The measured net export at the Blackwater complex (1.0 kg/s or 0.56 kg/m2/yr over the landward marsh area) was caused by northwesterly winds, which exported water and sediment on the subtidal timescale; tidally forced net fluxes were weak and precluded landward transport of suspended sediment from potential seaward sources. Though wind forcing also exported sediment at the Transquaking complex, strong tidal forcing and proximity to a turbidity maximum led to an import of sediment (0.031 kg/s or 0.70 kg/m2/yr). This resulted in a spatially averaged accretion of 3.9 mm/yr, equaling the regional relative sea level rise. Our results suggest that in areas where seaward sediment supply is dominant, seaward wetlands may be more capable of withstanding sea level rise over the short term than landward wetlands. We propose a conceptual model to determine a complex's tendency toward stability or instability based on sediment source, wetland channel location, and transport mechanisms. Wetlands with a reliable portfolio of sources and transport mechanisms appear better suited to offset natural and

  13. Concentration and chiral signature of chlordane in soils and sediments of the Central Tibetan Plateau, China: Transformation in the surficial process.

    Science.gov (United States)

    Yuan, Guo-Li; Wu, Ming-Zhe; Sun, Yong; Li, Jun; Han, Peng; Wang, Gen-Hou

    2015-11-01

    The fraction of trans-chlordane (TC) in chlordane was used to indicate racemic degradation while the enantiomer fractions (EFs) indicated enantioselective depletion. In 44 soils of the Central Tibetan Plateau, the fractions of TC ranged from 0.368 to 0.411. The EFs ranged from 0.174 to 0.696 for TC and from 0.483 to 0.672 for cis-chlordane (CC). (-) enantiomer excess (ee) was found to be 80.0% in the soils for TC and (+) ee was 86.5% for CC. The fraction of TC changed with the clay content while the EFs changed with the soil organic carbon. Meanwhile, the fractions of TC and the EFs were determined for the surficial sediments in Yamzhog Yumco Lake, which were compared with those in the soils at its catchment area. The composition and chiral signature of chlordane did not vary between soils and sediments. Our results will help to elucidate the transformation of chlordane in soils and in surficial transport.

  14. Dissipation of glyphosate and aminomethylphosphonic acid in water and sediment of two Canadian prairie wetlands.

    Science.gov (United States)

    Degenhardt, Dani; Humphries, David; Cessna, Allan J; Messing, Paul; Badiou, Pascal H; Raina, Renata; Farenhorst, Annemieke; Pennock, Dan J

    2012-01-01

    Glyphosate [N-(phosphonomethyl)glycine] is the active ingredient of several herbicide products first registered for use in 1974 under the tradename Roundup. The use of glyphosate-based herbicides has increased dramatically over the last two decades particularly in association with the adoption of glyphosate-tolerant crops. Glyphosate has been detected in a range of surface waters but this is the first study to monitor its fate in prairie wetlands situated in agricultural fields. An ephemeral wetland (E) and a semi-permanent wetland (SP) were each divided into halves using a polyvinyl curtain. One half of each wetland was fortified with glyphosate with the added mass simulating an accidental direct overspray. Glyphosate dissipated rapidly in the water column of the two prairie wetlands studied (DT(50) values of 1.3 and 4.8 d) which may effectively reduce the impact of exposure of aquatic biota to the herbicide. Degradation of glyphosate to its major metabolite aminomethylphosphonic acid (AMPA) and sorption of the herbicide to bottom sediment were more important pathways for the dissipation of glyphosate from the water column than movement of the herbicide with infiltrating water. Presently, we are not aware of any Canadian guidelines for glyphosate residues in sediment of aquatic ecosystems. Since a substantial portion of glyphosate entering prairie wetlands will become associated with bottom sediments, particularly in ephemeral wetlands, guidelines would need to be developed to assess the protection of organisms that spend all or part of their lifecycle in sediment.

  15. Retention and chemical speciation of uranium in an oxidized wetland sediment from the Savannah River Site

    Energy Technology Data Exchange (ETDEWEB)

    Li, Dien; Seaman, John C.; Chang, Hyun-Shik; Jaffe, Peter R.; Koster van Groos, Paul; Jiang, De-Tong; Chen, Ning; Lin, Jinru; Arthur, Zachary; Pan, Yuanming; Scheckel, Kirk G.; Newville, Matthew; Lanzirotti, Antonio; Kaplan, Daniel I.

    2014-05-01

    Uranium speciation and retention mechanism onto Savannah River Site (SRS) wetland sediments was studied using batch (ad)sorption experiments, sequential extraction desorption tests and U L{sub 3}-edge X-ray absorption near-edge structure (XANES) spectroscopy of contaminated wetland sediments. U was highly retained by the SRS wetland sediments. In contrast to other similar but much lower natural organic matter (NOM) sediments, significant sorption of U onto the SRS sediments was observed at pH <4 and pH >8. Sequential extraction tests indicated that the U(VI) species were primarily associated with the acid soluble fraction (weak acetic acid extractable) and NOM fraction (Na-pyrophosphate extractable). Uranium L3- edge XANES spectra of the U-retained sediments were nearly identical to that of uranyl acetate. The primary oxidation state of U in these sediments was as U(VI), and there was little evidence that the high sorptive capacity of the sediments could be ascribed to abiotic or biotic reduction to the less soluble U(IV) species. The molecular mechanism responsible for the high U retention in the SRS wetland sediments is likely related to the chemical bonding of U to organic carbon.

  16. Linking the historic 2011 Mississippi River flood to coastal wetland sedimentation

    Science.gov (United States)

    Falcini, Federico; Khan, Nicole S.; Macelloni, Leonardo; Horton, Benjamin P.; Lutken, Carol B.; McKee, Karen L.; Santoleri, Rosalia; Colella, Simone; Li, Chunyan; Volpe, Gianluca; D’Emidio, Marco; Salusti, Alessandro; Jerolmack, Douglas J.

    2012-01-01

    Wetlands in the Mississippi River deltaic plain are deteriorating in part because levees and control structures starve them of sediment. In Spring of 2011 a record-breaking flood brought discharge on the lower Mississippi River to dangerous levels, forcing managers to divert up to 3500 m3/s-1 of water to the Atchafalaya River Basin. Here we quantify differences between the Mississippi and Atchafalaya River inundation and sediment-plume patterns using field-calibrated satellite data, and assess the impact these outflows had on wetland sedimentation. We characterize hydrodynamics and suspended sediment patterns of the Mississippi River plume using in-situ data collected during the historic flood. We show that the focused, high-momentum jet from the leveed Mississippi delivered sediment far offshore. In contrast, the plume from the Atchafalaya was more diffuse; diverted water inundated a large area; and sediment was trapped within the coastal current. Maximum sedimentation (up to several centimetres) occurred in the Atchafalaya Basin despite the larger sediment load carried by the Mississippi. Minimum accumulation occurred along the shoreline between these river sources. Our findings provide a mechanistic link between river-mouth dynamics and wetland sedimentation patterns that is relevant for plans to restore deltaic wetlands using artificial diversions.

  17. The effect of river pulsing on sedimentation and nutrients in created riparian wetlands.

    Science.gov (United States)

    Nahlik, Amanda M; Mitsch, William J

    2008-01-01

    Sedimentation under pulsed and steady-flow conditions was investigated in two created flow-through riparian wetlands in central Ohio over 2 yr. Hydrologic pulses of river water lasting for 6 to 8 d were imposed on each wetland from January through June during 2004. Mean inflow rates during pulses averaged 52 and 7 cm d(-1) between pulses. In 2005, the wetlands received a steady-flow regime of 11 cm d(-1) with no major hydrologic fluctuations. Thirty-two sediment traps were deployed and sampled once per month in April, May, June, and July for two consecutive years in each wetland. January through March were not sampled in either year due to frozen water surfaces in the wetlands. Gross sedimentation (sedimentation without normalizing for differences between years) was significantly greater in the pulsing study period (90 kg m(-2)) than in the steady-flow study period (64 kg m(-2)). When normalized for different hydrologic and total suspended solid inputs between years, sedimentation for April through July was not significantly different between pulsing and steady-flow study periods. Sedimentation for the 3 mo that received hydrologic pulses (April, May, and June) was significantly lower during pulsing months than in the corresponding steady-flow months. Large fractions of inorganic matter in collected sediments indicated that allochthonous inputs were the main contributor to sedimentation in these wetlands. Organic matter fractions of collected sediments were consistently greater in the steady-flow study period (1.8 g kg(-1)) than in the pulsed study period (1.5 g kg(-1)), consistent with greater primary productivity in the water column during steady-flow conditions.

  18. Heavy metals in sediments and their bioaccumulation in Phragmites australis in the Anzali wetland of Iran

    Science.gov (United States)

    Esmaeilzadeh, Marjan; Karbassi, Abdolreza; Moattar, Faramarz

    2016-07-01

    Accumulation of metals in both sediments and Phragmites australis organs was studied. Samples were collected from seven stations located in Anzali wetland, Iran. The samples were analyzed by inductively coupled plasma mass spectrometry (ICP-MS). The results showed that concentration of the studied metals (except As and Cd) were higher in sediments than in P. australis organs. Metal accumulation was found to be significantly ( P <0.05) higher in roots than in above-ground organs of P. australis. The bioaccumulation factor (BAF) and the transfer factor (TF) also verified the highest rate of metal accumulation in roots and their reduced mobility from roots to the above-ground organs. Pearson correlation coefficient showed significant relationships between metal concentrations in sediments and those in plant organs. It should be pointed out that sediment and plant samples exhibited higher metal concentrations in eastern and central parts than in western and southern parts of the wetland. The mean concentrations of all studied elements (except for Fe, V and Al) were higher in these sediment samples than in the Earth's crust and shale. High accumulation of metals in P. australis organs (roots and shoots) is indicative of their high bioavailability in sediments of the wetland. The correlation between metal concentrations in sediments and in P. australis indicates that plant organs are good bioindicators of metal pollution in sediments of Anzali wetland.

  19. Mercury remediation in wetland sediment using zero-valent iron and granular activated carbon

    Science.gov (United States)

    Lewis, Ariel S.; Huntington, Thomas G.; Marvin-DiPasquale, Mark C.; Amirbahman, Aria

    2016-01-01

    Wetlands are hotspots for production of toxic methylmercury (MeHg) that can bioaccumulate in the food web. The objective of this study was to determine whether the application of zero-valent iron (ZVI) or granular activated carbon (GAC) to wetland sediment could reduce MeHg production and bioavailability to benthic organisms. Field mesocosms were installed in a wetland fringing Hodgdon Pond (Maine, USA), and ZVI and GAC were applied. Pore-water MeHg concentrations were lower in treated compared with untreated mesocosms; however, sediment MeHg, as well as total Hg (THg), concentrations were not significantly different between treated and untreated mesocosms, suggesting that smaller pore-water MeHg concentrations in treated sediment were likely due to adsorption to ZVI and GAC, rather than inhibition of MeHg production. In laboratory experiments with intact vegetated sediment clumps, amendments did not significantly change sediment THg and MeHg concentrations; however, the mean pore-water MeHg and MeHg:THg ratios were lower in the amended sediment than the control. In the laboratory microcosms, snails (Lymnaea stagnalis) accumulated less MeHg in sediment treated with ZVI or GAC. The study results suggest that both GAC and ZVI have potential for reducing MeHg bioaccumulation in wetland sediment.

  20. Improving water quality in agricultural catchments: sediment and nutrient retention in field wetlands

    Science.gov (United States)

    Ockenden, M. C.; Deasy, C.; Quinton, J. N.; Stoate, C.

    2012-04-01

    A recent update of Water Framework Directive classifications in the UK indicates that only 28% of water bodies currently achieve good ecological status and that agriculture is one of the main sectors responsible for the pressures contributed by sediment and nutrients. The use of edge-of-field features, such as field wetlands - small sediment and pollutant trapping features (

  1. Impact of sedimentation on wetland carbon sequestration in an agricultural watershed.

    Science.gov (United States)

    McCarty, Gregory; Pachepsky, Yakov; Ritchie, Jerry

    2009-01-01

    Landscape redistribution of soil C is common within agricultural ecosystems. Little is known about the effects of upland sediment deposition on C dynamics within riparian wetlands. To assess sedimentation impact, we obtained profile samples of wetland soil and used the combination of (137)Cs, (210)Pb, and (14)C chronological markers to determine rates of C sequestration and mineral deposition over the history of a wetland within a first-order catchment under agricultural management in the coastal plains of the United States. Substantial post settlement deposition in the wetland soil was evidenced in places by a 20- to 40-cm layer of mineral soil that buried the original histosol. Soil profiles contained a minimum in C content within the top 35 cm of the profile which originated from a rapid deposition from low C upland soils. Radiocarbon and radioisotope dating showed that increases in C above this minimum were the result of C sequestered in the past approximately 50 yr. Modeling the kinetics of modern C dynamics using the (137)Cs and (210)Pb markers within these surface profiles provides strong evidence for accelerated C sequestration associated with mineral sediment deposition in the ecosystem. These findings indicate that at the landscape scale, dilution of ecosystem C by import of low C upland sediment into wetlands stimulates C sequestration by pulling soil C content below some pedogenic equilibrium value for the ecosystem. They also indicate that over the history of the wetland, rates of C accretion may be linked to mineral soil deposition.

  2. Nickel, Lead and Zinc Contamination in the Surface Sediments of Agh Gel Wetland, Iran

    Directory of Open Access Journals (Sweden)

    Soheil Sobhan Ardakani

    2016-07-01

    Full Text Available Background & Aims of the Study: Due to the increased human activities around the Agh Gel wetland, this study aimed to measured accumulations of heavy metals (Ni, Pb and Zn in the surface sediment samples taken from this wetland. Materials & Methods: Samples were taken from 10 stations and exposed to bulk digestion and chemical partitioning. Finally, Ni, Pb and Zn concentrations were monitored with ICP-OES in the sediments. Also, geo-accumulation index, contamination factor and pollution load index were used to evaluate the magnitude of contaminants in the sediment profile. Results: The results showed, the average of metal concentration in samples (mg kg-1 wet weight were 34.20±3.58 for Ni, 25.37±2.52 for Pb and 127.20±15.21 for Zn, respectively. Therefore, the pattern of metal concentrations in sediment was determined as Zinc>Nickel >Lead. According to the mean I-geo values, sediments' qualities are classified as unpolluted category for Ni and Pb. Also, sediment's quality is classified as unpolluted to moderately polluted for Zn. The CF values for all elements are classified as moderate contamination. The PLI values indicated that metal pollution exists for all sampling stations. Conclusions: The obtained results indicated that the Agh Gel wetland has a potential to threaten by chemical pollutants such as agricultural effluent. So, in order to preserve the environment of the Agh Gel wetland from deterioration, monitoring of water and sediment qualities is recommended periodically.

  3. Analysis of Heavy Metals in Surface Sediments from Agh Gel Wetland, Iran

    Directory of Open Access Journals (Sweden)

    Soheil Sobhanardakani

    2016-06-01

    Full Text Available Background: Soil and sediment serve as major reservoir for contaminants as they possess ability to bind various chemicals together. In this study the concentrations of heavy metals Cd, Cr and Cu were analyzed in surface sediments of Agh Gel Wetland in west of Iran. Methods: The sediment samples were taken from 10 stations. The samples were subjected to bulk digestion and chemical partitioning and Cd, Cr and Cu concentrations of the sediments were determined by ICP-OES. Geo-accumulation index (I-geo, Contamination factor (CF and Pollution load index (PLI were used to evaluate the magnitude of contaminants in the sediment profile. Results: The mean sediment concentrations (mg kg-1 dry weight ranged within 0.20-0.29 (Cd, 58-71 (Cr and 23-36 (Cu. According to the I-geo values, the sediments' qualities are classified as unpolluted to moderately polluted category. According to the CF values, the sediments' qualities are classified as low to moderate contamination. Furthermore, the PLI values indicated that there were no metal pollution exists for all sampling stations. Conclusion: The Agh Gel Wetland is potential to be threatened by chemical pollutants such as agricultural effluent. So to preserve the environment of the Agh Gel Wetland from deterioration, periodically monitoring of the water and sediment qualities is recommended.

  4. In situ detection of the Clostridium botulinum type C1 toxin gene in wetland sediments with a nested PCR assay

    Science.gov (United States)

    Williamson, J.L.; Rocke, T.E.; Aiken, Judd M.

    1999-01-01

    A nested PCR was developed for detection of the Clostridium botulinum type C1 toxin gene in sediments collected from wetlands where avian botulism outbreaks had or had not occurred. The C1 toxin gene was detected in 16 of 18 sites, demonstrating both the ubiquitous distribution of C. botulinum type C in wetland sediments and the sensitivity of the detection assay.

  5. Origin and distribution of hydrocarbons and organic matter in the surficial sediments of the Sfax-Kerkennah channel (Tunisia, Southern Mediterranean Sea).

    Science.gov (United States)

    Zaghden, Hatem; Tedetti, Marc; Sayadi, Sami; Serbaji, Mohamed Moncef; Elleuch, Boubaker; Saliot, Alain

    2017-04-15

    We investigated the origin and distribution of aliphatic and polycyclic aromatic hydrocarbons (AHs and PAHs) and organic matter (OM) in surficial sediments of the Sfax-Kerkennah channel in the Gulf of Gabès (Tunisia, Southern Mediterranean Sea). TOC, AH and PAH concentrations ranged 2.3-11.7%, 8-174μgg(-1)sed.dw and 175-10,769ngg(-1)sed.dw, respectively. The lowest concentrations were recorded in the channel (medium sand sediment) and the highest ones in the Sfax harbor (very fine sand sediment). AHs, PAHs and TOC were not correlated for most of the stations. TOC/N and δ(13)C values revealed a mixed origin of OM with both marine and terrestrial sources. Hydrocarbon molecular composition highlighted the dominance of petrogenic AHs and the presence of both petrogenic and pyrogenic PAHs, associated with petroleum products and combustion processes. This work underscores the complex distribution patterns and the multiple sources of OM and hydrocarbons in this highly anthropogenized coastal environment.

  6. Magnetic properties of surficial sediments in Lake Ogawara on the Pacific coast of northeastern Japan: spatial variability and correlation with brackish water stratification

    Science.gov (United States)

    Hayashida, Akira; Nakano, Ryoma; Nagashima, Aya; Seto, Koji; Yamada, Kazuyoshi; Yonenobu, Hitoshi

    2015-10-01

    To examine limnological conditions in Lake Ogawara on the Pacific coast of northwestern Japan, we investigated the magnetic properties of dredged bottom sediment originally collected from the lake in the summer of 2011. We used non-destructive methods to measure the low-field magnetic susceptibility shortly after sampling, and anhysteretic remanent magnetization (ARM) was assessed in 2012 and 2015. The ARM acquisition and demagnetization curves from littoral sites showed several patterns that reflect the provenance of the sediments. At water depths below 10 m, the magnetic susceptibility and ARM of greenish black mud with high organic content decreased considerably with the increase in water depth, but ARM increased slightly at water depths greater than 16 m. We also found that the magnetic concentrations of mud samples were reduced markedly during a period of storage for about 3 years. We attributed these reductions to diagenetic loss of magnetic minerals, which had been enhanced at deeper sites. It is possible that the ARM carriers in deeper areas were derived from authigenic formation of iron sulfide or from deposition of suspended matter in the hypolimnion water. We propose that the magnetic properties of surficial sediments are controlled by limnological stratification of the brackish lake water, thus possibly providing an analog for down-core variations of magnetic parameters associated with the modification of magnetic minerals during reductive diagenesis.

  7. Modeling sediment accumulation in North American playa wetlands in response to climate change, 1940-2100

    Science.gov (United States)

    Burris, Lucy; Skagen, Susan K.

    2013-01-01

    Playa wetlands on the west-central Great Plains of North America are vulnerable to sediment infilling from upland agriculture, putting at risk several important ecosystem services as well as essential habitats and food resources of diverse wetland-dependent biota. Climate predictions for this semi-arid area indicate reduced precipitation which may alter rates of erosion, runoff, and sedimentation of playas. We forecasted erosion rates, sediment depths, and resultant playa wetland depths across the west-central Great Plains and examined the relative roles of land use context and projected changes in precipitation in the sedimentation process. We estimated erosion with the Revised Universal Soil Loss Equation (RUSLE) using historic values and downscaled precipitation predictions from three general circulation models and three emissions scenarios. We calibrated RUSLE results using field sediment measurements. RUSLE is appealing for regional scale modeling because it uses climate forecasts with monthly resolution and other widely available values including soil texture, slope and land use. Sediment accumulation rates will continue near historic levels through 2070 and will be sufficient to cause most playas (if not already filled) to fill with sediment within the next 100 years in the absence of mitigation. Land use surrounding the playa, whether grassland or tilled cropland, is more influential in sediment accumulation than climate-driven precipitation change.

  8. Assessment of metal pollution in the Anzali Wetland sediments using chemical partitioning method and pollution indices

    Institute of Scientific and Technical Information of China (English)

    ESMAEILZADEH Marjan; KARBASSI Abdolreza; MOATTAR Faramarz

    2016-01-01

    Metal pollution in aquatic ecosystems is of immense importance. Under various environment circumstances, the metal contents of sediments can enter into the overlying water body leading to severe toxicity. This study aims to determine metal concentrations in sediments of Anzali International Wetland in Iran. Chemical partitioning method is used to determine the portion of anthropogenic pollution and the mobility potential of each metal. The intensity of metal pollution in sediments of the wetland is assessed using three reliable indices. The results of chemical partitioning reveal that cadmium bear the highest risk of being released into the aquatic environment and high amount of manganese in sulfide bond phase implies the initiation of redox state in aquatic environment of the Anzali Wetland. The results of chemical partitioning studies show that Pb, Cd, Mn and As have the highest anthropogenic portion. Cluster analysis also confirms the results of chemical partitioning and indicates that the mentioned metals can be originated from anthropogenic sources. Sediment pollution indices, including, Igeo, IPOLL, and m-ERM-Q reveal that metals are in the range of low to moderate pollution and also show that the highest metal pollution is in the eastern and central parts of the wetland. This can be ascribed to rivers which are the recipient of industrial, agricultural and municipal wastewaters and flow into these parts of the wetland.

  9. Geoelectrical Analyses of Sulfurous Wetland Sediments and Weathered Glacial Till in the Prairie Pothole Region

    Science.gov (United States)

    Levy, Z. F.; Siegel, D. I.; Moucha, R.; Fiorentino, A. J., II; Mills, C. T.; Goldhaber, M. B.; Rosenberry, D. O.

    2015-12-01

    Millions of prairie wetlands occur in topographic depressions throughout the Prairie Pothole Region (PPR) of North America, an important ecoregion for amphibians and migratory birds. Climate is known to drive complex critical zone processes determining sulfur fate and transport in the PPR, but the specific mechanisms controlling the storage and release of salinity beneath the wetlands remain poorly understood. To help clarify this, we conducted a DC resistivity field survey of a closed-basin groundwater discharge wetland at the Cottonwood Lake Study Area, North Dakota; and collected wetland cores along one of the survey transects for laboratory analyses of resistivity, porewater/solid-phase geochemistry, and other physical properties. Inversions of our field survey delineate two primary geoelectrical layers beneath the wetland: the top ~8 m of wetland sediments and weathered glacial till (ρ25 = 4 - 5 Ω-m) overlying more resistive glacial till at depth (ρ25 = 7 - 12 Ω-m). Conductive lenses (ρ25 = 1 - 2 Ω-m) occur within the upper layer at 2 - 3 m depths in the center of the wetland and along a concentric band within the current ponded area, which corresponds to the location of the pond shoreline before extremely wet conditions in the 1990's expanded the wetland. The resistivities of wetland core segments (ρ25 = 2 - 7 Ω-m) match well with the upper layer inferred from the field survey, and show an inverse trend of bulk core to porewater resistivity for clay-rich intervals due to variations in moisture content. Our results demonstrate that geospatial patterns of subsurface salinity relate to wetland hydrodynamics during dry-wet climate cycles and should be considered when using geoelectrical methods to upscale geochemical measurements in PPR wetlands.

  10. The inhibition of Clostridium botulinum type C by other bacteria in wetland sediments

    Science.gov (United States)

    Sandler, Renee J.; Rocke, Tonie E.; Yuill, Thomas M.

    1998-01-01

    Bacteria with inhibitory activity against Clostridium botulinum type C were isolated from 32% of sediment samples (n = 1600) collected from 10 marshes in a northern California wetland over a 12 mo period. Aerobic and anaerobic bacteria with inhibitory activity were isolated from 12% and 23% of the samples, respectively. Bacteria with inhibitory activity were isolated from all 10 study sites and throughout the year. This study demonstrates that bacteria with inhibitory activity against C. botulinum type C occur naturally in wetland sediments.

  11. Sebkhet Karkura: an example of a semi-arid Mediterranean wetland rich in biotic sediments

    Science.gov (United States)

    Abdulsamad, Esam O.; Elbabour, Mansour M.

    2014-05-01

    Habitat wetlands in Libya may be grouped into several distinct varieties, according to climate, water supply, soils, and biotic diversity. They include coastal Sebkhas (salt marshes), karst lakes, Wadi estuaries, below sea-level desert lakes, and balat flats (playas) where the soil is saturated part of some rainy seasons forming a kind of ephemeral, shallow lakes in pre-desert areas. The most prominent, however, are the extensive coastal salt marshes. These have either organic or inorganic soils, or both, depending on their location and climate conditions. Soils common to most coastal wetlands are composed largely of inorganic material in the form of sand, silt, or clay; in addition to organic material formed by decayed plants and various biotic sediments. For the purpose of the present poster, however, Sebkhet Karkura, an extensive stretch of about 50 km square (20 km long by an average width of 2.5 km) of Sebkha/wetland formation, located about 80 km southwest of Benghazi, will serve as an example of coastal Sebkhas. Here, the sediments are consisting mostly of dark earth brown sandy silt with salt and gypsum. Pure-salt deposits are normally extracted for salt processing in the area. Loams, silt, gravel, and calcareous sand are also present. At the surface of the wetland, calcarenites are fairly common but sand-beach and sand-dunes are representing the major sediments along the coastal wetland area. The recent biotal components of these sediments are described and a number of recent small-sized benthic seashells, belonging to phylum mollusca, have been investigated along the seaside of Sabkhet Karkura and several species have been identified. It is worth noting that Sebkhet Karkura, as well as other similar coastal wetlands, currently face serious threats due to human action, especially over exploitation of their resources, urban encroachments, dredging, and solid waste dumping. Increased awareness on the part of the general public of wetland ecological values

  12. Processes controlling forms of phosphorus in surficial sediments from the eastern Arabian Sea impinged by varying bottom water oxygenation conditions

    Digital Repository Service at National Institute of Oceanography (India)

    PrakashBabu, C.; Nath, B.N.

    in OMZ sediments from the NE Arabian Sea may indicate a higher degree of regeneration and diagenetic transformation of labile forms of P to other phases. Authigenic phosphorus (P sub(aut)) fraction varies by a factor of 2-8 in sediments from the OMZ when...

  13. Assessment of bed sediment metal contamination in the Shadegan and Hawr Al Azim wetlands, Iran.

    Science.gov (United States)

    Nasirian, Hassan; Irvine, K N; Sadeghi, Sayyed Mohammad Taghi; Mahvi, Amir Hossein; Nazmara, Shahrokh

    2016-02-01

    The Shadegan and Hawr Al Azim wetlands are important natural resources in southwestern Iran, yet relatively little work has been done to assess ecosystem health of the wetlands. Bed sediment from both wetlands was sampled in individual months between October, 2011 and December, 2012 and analyzed for As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Pb, and Zn using inductively coupled plasma optical emission spectrometry (ICP-OES). The metals data were evaluated using a combination of sediment quality guidelines from the Ontario Ministry of Energy and Environment (MOEE, Canada), enrichment factors (EFs), and a geo-accumulation index (Igeo) approach. The sediments exceeded MOEE Lowest Effect Levels (LELs) consistently for Cr and Cu and a small proportion of samples (5%) for Hg. Levels of As, Cd, Fe, Pb, and Zn did not exceed LELs and none of the samples exceeded the Severe Effect Levels (SELs). In addition to the sediment guidelines, both the EF and Igeo calculations suggested levels of Mn and Fe were severely enriched, while the EF indicated Cd was slightly enriched. Metal levels in the Shadegan wetland exhibited both spatial and seasonal trends. Metal levels were greater near input areas from agricultural, urban, and industrial discharges and runoff as compared to the more remote and quiescent central part of the wetland. Except for Fe, the metal levels were greater in the wet season as compared to the dry season, perhaps due to greater stormwater runoff and sediment loads. This study provides baseline data which can be used to support development of appropriate contaminant source management strategies to help ensure conservation of these valuable wetland resources.

  14. Land use effects on pesticides in sediments of prairie pothole wetlands in North and South Dakota

    Science.gov (United States)

    McMurry, Scott T.; Belden, Jason B.; Smith, Loren M.; Morrison, Shane A.; Daniel, Dale W.; Euliss, Betty R.; Euliss, Ned H. Jr.; Kensinger, Bart J.; Tangen, Brian

    2016-01-01

    Prairie potholes are the dominant wetland type in the intensively cultivated northern Great Plains of North America, and thus have the potential to receive pesticide runoff and drift. We examined the presence of pesticides in sediments of 151 wetlands split among the three dominant land use types, Conservation Reserve Program (CRP), cropland, and native prairie, in North and South Dakota in 2011. Herbicides (glyphosate and atrazine) and fungicides were detected regularly, with no insecticide detections. Glyphosate was the most detected pesticide, occurring in 61% of all wetlands, with atrazine in only 8% of wetlands. Pyraclostrobin was one of five fungicides detected, but the only one of significance, being detected in 31% of wetlands. Glyphosate was the only pesticide that differed by land use, with concentrations in cropland over four-times that in either native prairie or CRP, which were equal in concentration and frequency of detection. Despite examining several landscape variables, such as wetland proximity to specific crop types, watershed size, and others, land use was the best variable explaining pesticide concentrations in potholes. CRP ameliorated glyphosate in wetlands at concentrations comparable to native prairie and thereby provides another ecosystem service from this expansive program.

  15. Verdine and other associated authigenic (glaucony, phosphate) facies from the surficial sediments of the southwestern continental margin of India

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, V.P.; Lamboy, M.; Dupeuble, P.A.

    Green grains, pale green-brown infillings of foraminifer tests and brown friable aggregates occur in the coarse fraction of the surface sediments from the southwestern continental margin of India, between the Periyar River in the north and Quilon...

  16. Trace Metal Accumulation in Sediments and Benthic Macroinvertebrates before and after Maintenance of a Constructed Wetland

    Science.gov (United States)

    Periodic maintenance of stormwater best management practices (BMP) includes the removal of accumulated sediment. The resulting impact on trace metal concentrations of copper (Cu), lead (Pb), and zinc (Zn) in a constructed stormwater wetland BMP on Staten Island, NY was investiga...

  17. Wetland Management Reduces Sediment and Nutrient Loading to the Upper Mississippi River

    Science.gov (United States)

    Restored riparian wetlands in the Upper Mississippi River basin have the potential to remove sediment and nutrients from tributaries before they flow into the Mississippi River. For 3 yr we calculated retention efficiencies of a marsh complex, which consisted of a restored marsh...

  18. Ecological Risk Assessment of Polycyclic Aromatic Componds in the Surface Sediments of Anzali Wetland in 2010

    Directory of Open Access Journals (Sweden)

    Rokhsareh Azimi Yancheshmeh

    2014-10-01

    Conclusion: In comparison with sediment quality guidelines (SQGs used in this study, the concentrations of most PAH compounds in Anzali Wetland rarely lead to adverse biological effects. However, concentrations of some of these compounds can cause acute toxic effects. Therefore, further studies including toxicity and bioaccumulation tests and survey of benthic community composition, especially in areas exceeded SQGs are essential for proper management.

  19. WETLANDS AS BMPs AND THEIR USE IN TRADING OF NUTRIENT AND SEDIMENT REDUCTION CREDITS

    Science.gov (United States)

    WETLANDS AS BMPs AND THEIR USE IN TRADING OF NUTRIENT AND SEDIMENT REDUCTION CREDITS J. Schubauer-Berigan (NRMRL), D. Brown (NRMRL), D. Burden (NRMRL), T. Canfield (NRMRL), W. Franz (R5), J. Kressel (NRMRL), M. Heberling (NCEA), K. Hurld (OW), C. Lane (NERL), M. Morrison (NRMR...

  20. Seasonal variation of polychlorinated biphenyl congeners in surficial sediment, trapped settling material, and suspended particulate material in Lake Michigan, USA.

    Science.gov (United States)

    Robinson, Sander D; Landrum, Peter F; Van Hoof, Patricia L; Eadie, Brian J

    2008-02-01

    A unique time series of surface sediment, trapped settling material, and suspended particulate material polychlorinated biphenyl (PCB) samples were collected at a 45-m deep site off Grand Haven (MI, USA) over a 14-month period. Both concentrations and congener distributions remained constant for the sediments, although there were seasonal and interannual variability in the other matrices. Trapped settling material and suspended particulate material PCB concentrations were substantially lower (~50%) in 1997 than in the samples from December 1997 through July 1998. The cause could not be determined from the data collected, but there were some very large storms during the winter-spring period of 1998, resulting in major sediment resuspension throughout the southern basin. Observed seasonal variation in PCB concentration and congener distribution on particles likely was due to the changes in particle composition. These include particle size and the source of particles (such as the amount of resuspended sediment in trapped settling material), and the role of diagenesis of the organic matter on particles.

  1. Mercury and methylmercury contamination in surficial sediments and clams of a coastal lagoon (Pialassa Baiona, Ravenna, Italy)

    Science.gov (United States)

    Trombini, Claudio; Fabbri, Daniele; Lombardo, Marco; Vassura, Ivano; Zavoli, Elisabetta; Horvat, Milena

    2003-11-01

    The Ramsar site Pialassa Baiona is an intertidal brackish lagoon lying 5 km north of the city of Ravenna and covering a surface area of about 1100 ha. From 1958 to 1976 Pialassa Baiona was heavily impacted by industrial pollution; mercury, polycyclic aromatic hydrocarbons, polymers were among the most important pollutants which nowadays contaminate the sedimentary compartment. Following earlier investigations on total mercury (THg) distribution and bioavailability, this study is focused on mercury speciation in sediments and clams. Methylmercury ( MMHg) concentrations were determined in surface sediments (0-5 cm) in different seasons, and compared to THg. Selected sediments were subjected to a sequential extraction procedure to study solid state THg distribution. Operationally, three fractions of inorganic mercury were defined: mobile mercury ( Hgm), humic acid complexed mercury ( Hgha), and sulphide-bound mercury ( Hgs). THg and MMHg concentrations in sediments ranged in the 0.2-250 μg g -1 and 0.13-45 ng g -1 d.w. intervals, respectively. MMHg/THg ratios were higher in summer as well as in sites where the THg burden was lower; the highest MMHg/THg values were observed in Chiaro del Pontazzo, an area subjected to a drastic reduction of salinity. THg and MMHg concentrations were also determined in tissues of clams ( Tapes philippinarum) collected in the lagoon. MMHg in clams felt in the 180-470 ng g -1 interval and accounts for 72-95% of tissue THg.

  2. Geochemical interactions between process-affected water from oil sands tailings ponds and North Alberta surficial sediments.

    Science.gov (United States)

    Holden, A A; Donahue, R B; Ulrich, A C

    2011-01-25

    In Northern Alberta, the placement of out-of-pit oil sands tailings ponds atop natural buried sand channels is becoming increasingly common. Preliminary modeling of such a site suggests that process-affected (PA) pond water will infiltrate through the underlying clay till aquitard, reaching the sand channel. However, the impact of seepage upon native sediments and groundwater resources is not known. The goal of this study is to investigate the role of adsorption and ion exchange reactions in the clay till and their effect on the attenuation or release of inorganic species. This was evaluated using batch sorption experiments (traditional and a recent modification using less disturbed sediment samples) and geochemical modeling with PHREEQC. The results show that clay till sediments have the capacity to mitigate the high concentrations of ingressing sodium (600 mg L(-1)), with linear sorption partitioning coefficients (K(d)) of 0.45 L kg(-1). Ion exchange theory was required to account for all other cation behaviour, precluding the calculation of such coefficients for other species. Qualitative evidence suggests that chloride will behave conservatively, with high concentrations remaining in solution (375 mg L(-1)). As a whole, system behaviour was found to be controlled by a combination of competitive ion exchange, dissolution and precipitation reactions. Observations, supported by PHREEQC simulations, suggest that the influx of PA water will induce the dissolution of pre-existing sulphate salts. Sodium present in the process-affected water will exchange with sediment-bound calcium and magnesium, increasing the divalent ions' pore fluid concentrations, and leading to the precipitation of a calcium-magnesium carbonate mineral phase. Thus, in similar tailings pond settings, particularly if the glacial till coverage is thin or altogether absent, it is reasonable to expect that high concentrations of sodium and chloride will remain in solution, while sulphate

  3. Mineral provinces and material provenance of the surficial sediments near the Zhongsha Islands in the South China Sea

    Institute of Scientific and Technical Information of China (English)

    YAN Quanshu; SHI Xuefa; WANG Kunshan

    2007-01-01

    Characteristics and distribution patterns of clastic minerals (0.063~0.125 mm) in bottom sediments represent a significant indicator for the identification of the origin of sediment. One hundred and fourteen surface sediment samples, which were collected from the area near the Zhongsha Islands in the South China Sea, were analysed to identify the mineral suites and their distributions in the study area. The area can be divided into three mineral provinces: (Ⅰ) a province of biogenic minerals, which mainly originate from the Zhongsha Atoll; (Ⅱ) a province of volcanogenic minerals, which are mainly derived from local basaltic seamounts and small-scale volcanoes that are probably erupting, with some influences from the island-arc volcanic region around the South China Sea; and (Ⅲ) a mixed mineral province whose material source includes biogenic minerals, volcanogenic minerals and terrigenous minerals; the last province can be subdivided into a mixed mineral sub-province of the northeastern part of the study area, in which terrigenous minerals are mainly derived from China's Mainland and do not exceed 17°N, and a mixed mineral sub-province of the southeastern part of the study area, in which terrigenous minerals are derived from Kalimantan and Indochina Peninsula and might be further transported into the deep sea basin through submarine canyons.

  4. Measurement of Atrazine Adsorption onto Surficial Sediments (Natural Surface Coatings)——New Evidence for the Importance of Fe Oxides

    Institute of Scientific and Technical Information of China (English)

    LI Yu; WANG Ao; GAO Qian; WANG Xiao-li

    2009-01-01

    To reveal the relative contribution of the components, Fe, Mn oxides or organic materials(OMs) in the surficial sediments(SSs), and the natural surface coating samples(NSCSs) to adsorbing atrazine(AT), a selective chemical extraction technique was employed, to remove the different components, and the adsorption characteristics of AT on the SSs and the NSCSs were investigated. The observed adsorptions of AT on the original and extracted SSs and NSCSs were analyzed by nonlinear least squares fitting(NLSF) to estimate the relative contribution of the com-ponents. The results showed that the maximum adsorption of AT on the NSCSs was greater than that in the SSs, be-fore and after extraction treatments, implying that the NSCSs were more dominant than the SSs for organic pollutant adsorption. It was also found that the Fe oxides, OMs, and residues in SSs(NSCSs) facilitated the adsorption of AT, but Mn oxides directly or indirectly restrained the interaction of AT with SSs(NSCSs) particles. The contribution of the Fe oxides to AT adsorption was more than that of OMs; the greatest contribution to AT adsorption on a molar ba-sis was from the Fe oxides in the nonresidual fractions, indicating that the Fe oxides played an important role in con-trolling the environmental behavior of AT in an aquatic environment.

  5. Distribution and diversity of diatom assemblages in surficial sediments of shallow lakes in Wapusk National Park (Manitoba, Canada) region of the Hudson Bay Lowlands.

    Science.gov (United States)

    Jacques, Olivier; Bouchard, Frédéric; MacDonald, Lauren A; Hall, Roland I; Wolfe, Brent B; Pienitz, Reinhard

    2016-07-01

    The hydrology of shallow lakes (and ponds) located in the western Hudson Bay Lowlands (HBL) is sensitive to climate warming and associated permafrost thaw. However, their biological characteristics are poorly known, which hampers effective aquatic ecosystem monitoring. Located in northern Manitoba along the southwestern coast of Hudson Bay, Wapusk National Park (WNP) encompasses numerous shallow lakes representative of the subarctic zone. We analyzed the distribution and diversity of diatom (microscopic algae; class Bacillariophyceae) assemblages in surficial sediments of 33 lakes located in three different ecozones spanning a vegetation gradient, from NE to SW: the Coastal Fen (CF), the Interior Peat Plateau (IPP), and the Boreal Spruce Forest (BSF). We found significant differences (P lakes, and CF and BSF lakes, but not between IPP and BSF lakes. These results are consistent with water chemistry measurements, which indicated distinct limnological conditions for CF lakes. Diatom communities in CF lakes were generally dominated by alkaliphilous taxa typical of waters with medium to high conductivity, such as Nitzschia denticula. In contrast, several IPP and BSF lakes were dominated by acidophilous and circumneutral diatom taxa with preference for low conductivity (e.g., Tabellaria flocculosa, Eunotia mucophila, E. necompacta var. vixcompacta). This exploratory survey provides a first detailed inventory of the diatom assemblages in the WNP region needed for monitoring programs to detect changes in shallow lake ecosystems and ecozonal shifts in response to climate variations.

  6. Influence of an aerobic sediment-water interface in relation to reduced risk of phosphorus leaching from re-established wetlands

    DEFF Research Database (Denmark)

    Forsmann, Ditte M.; Kjærgaard, Charlotte

    water interactions are of fundamental importance for the biogeochemical processes controlling phosphorus dynamics in wetlands, and different hydrological pathways such as groundwater discharge and surface water flooding are operating within wetlands (Hoffmann et al., 2009). During groundwater discharge...... water passes through the wetland sediment and carry soluble iron and phosphorus by convection to the sediment-water interface. During surface water flooding phosphorus fluxes from the sediment will be dominated by diffuse fluxes. The eventual loss of phosphorus mobilized within the anaerobic sediment...

  7. New Jersey (USA) wetlands past, present and future: using sediment archives to inform and guide wetland protection, restoration and resilience

    Science.gov (United States)

    Shaw, T.; Clear, J.; Horton, B.; Khan, N.; Nikitina, D.; Enache, M. D.; Potapova, M.; Frizzera, D.; Procopio, N.; Vane, C. H.; Walker, J. S.

    2016-12-01

    Due to the rapid and pervasive loss of coastal wetland ecosystems and the enumerable services they provide, recent attention has been given to understand their resilience and response to natural and anthropogenic impacts. Knowledge gaps exist particularly regarding response times of wetland ecosystems to natural factors (storms and sea-level rise) and the appropriate indices or metrics of ecosystem health to be incorporated in management practices to achieve restoration goals. Here we present results from monitoring studies and stratigraphic investigations from marshes across the New Jersey, USA shoreline from Delaware Bay to Raritan Bay (˜210 km of coastline that vary in degree of urbanization and anthropogenic disturbances) that address these limitations. In Delaware Bay, we identify a series of abrupt contacts (mud-peat couplets) from a sequence spanning the past two thousand years that we infer result from erosive storm events. By dating the base of these contacts and the return to high salt marsh peat, we are able to estimate the recovery time of marshes under varying rates of sea-level rise. In marshes from Great Sound to Raritan Bay, we use microfossils (e.g., foraminifera, diatoms) as indices of ecosystem health. We monitor the response of microfossils to natural (e.g., changes in salinity or inundation frequency from sea-level rise) and anthropogenic (e.g., nutrient loading) influences and apply quantitative paleoenvironmental reconstruction techniques to sediment archives to understand the relative influence of these factors on New Jersey wetlands over the past two thousand years. These results can be used to inform future coastal wetland restoration targets and as a model to develop site-specific goals in other regions.

  8. New Jersey (USA) wetlands past, present and future: using sediment archives to inform and guide wetland protection, restoration and resilience

    Science.gov (United States)

    Khan, Nicole; Clear, Jennifer; Horton, Benjamin; Nikitina, Daria; Enache, Mihaela; Potapova, Marina; Frizzera, Dorina; Procopio, Nicholas; Vane, Christopher; Shaw, Timothy; Walker, Jennifer

    2016-04-01

    Due to the rapid and pervasive loss of coastal wetland ecosystems and the enumerable services they provide, recent attention has been given to their protection and restoration. Knowledge gaps exist, however, that limit the efficacy of restoration efforts, particularly regarding response times of wetland ecosystems to natural (storms and sea-level rise) and anthropogenic impacts and the appropriate indices or metrics of ecosystem health to be incorporated in management practices to achieve restoration goals. Here we present results from monitoring studies and stratigraphic investigations from marshes across the New Jersey, USA shoreline from Delaware Bay to Raritan Bay (~210 km of coastline that vary in degree of urbanization and anthropogenic disturbances) that address these limitations. In Delaware Bay, we identify a series of abrupt contacts (mud-peat couplets) from a sequence spanning the past two thousand years that we infer result from erosive storm events. By dating the base of these contacts and the return to high salt marsh peat, we are able to estimate the recovery time of marshes under varying rates of sea-level rise. In marshes from Great Sound to Raritan Bay, we use microfossils (e.g., foraminifera, diatoms) as indices of ecosystem health. We monitor the response of microfossils to natural (e.g., changes in salinity or inundation frequency from sea-level rise) and anthropogenic (e.g., nutrient loading) influences and apply quantitative paleoenvironmental reconstruction techniques to sediment archives to understand the relative influence of these factors on New Jersey wetlands over the past two thousand years. These results can be used to inform future coastal wetland restoration targets and as a model to develop site-specific goals in other regions.

  9. Morphology of submarine canyon system and geotechnical properties of surficial sediments across the Peru-Chile forearc

    Energy Technology Data Exchange (ETDEWEB)

    Bergersen, D.D.; Coulbourn, W.T.; Moberly, R.

    1989-03-01

    During August 1987, a SeaMARC II side-scan and sampling survey was conducted across the Peru-Chile forearc from 17/degrees/30'S to 19/degrees/30'S. Side-scan images reveal a complex submarine canyon system. Incised canyons meander across the Arequipa basin; their sinuosity results from erosion and cutbank slumping of the basin sediments. Lenticular packets of strata visible in reprocessed digital single-channel seismic profiles are interpreted to be buried channels. Tributary canyons coalesce into a single canyon at the structural high that deviates from its north-south course to a northeast-southwest course as a result of stream piracy. A dendritic drainage basin forming on the midslope may be the rejuvenation of an abandoned channel. Sediment properties were measured on 42 free-fall cores and 7 piston cores recovered both in and around the submarine canyon. Olive-gray (5Y 3/2) hemipelagic mud is the predominant sediment across the forearc. Most cores exhibit a small degree of bioturbation and thin laminae of sand; the number of sand laminae increases as the distance away from the canyon decreases. Shear strengths, averaged over a 1-m core length, decrease slightly with water depth. Carbonate content in all samples from this area is negligible with the exception of one piston core recovered from the upper reaches of the canyon, the bottom of which is composed of gravel- and sand-size shell fragments. Bulk mineralogy, determined from semiquantitative analysis of x-ray diffraction patterns, shows a decrease in relative feldspar percent and an increase in total clay content with increasing water depth. Preliminary analysis of core tops shows a mean grain size in the medium to very fine silt class, with increasing grain size toward the canyon. Smear slide counts generally show a surprisingly low abundance of volcanic glass and biogenic material, particularly diatoms.

  10. Adsorption, sedimentation, and inactivation of E. coli within wastewater treatment wetlands.

    Science.gov (United States)

    Boutilier, L; Jamieson, R; Gordon, R; Lake, C; Hart, W

    2009-09-01

    Bacteria fate and transport within constructed wetlands must be understood if engineered wetlands are to become a reliable form of wastewater treatment. This study investigated the relative importance of microbial treatment mechanisms in constructed wetlands treating both domestic and agricultural wastewater. Escherichia coli (E. coli) inactivation, adsorption, and settling rates were measured in the lab within two types of wastewater (dairy wastewater lagoon effluent and domestic septic tank effluent). In situ E. coli inactivation was also measured within a domestic wastewater treatment wetland and the adsorption of E. coli was also measured within the wetland effluent. Inactivation of E. coli appears to be the most significant contributor to E. coli removal within the wastewaters and wetland environments examined in this study. E. coli survived longer within the dairy wastewater (DW) compared to the domestic wastewater treatment wetland water (WW). First order rate constants for E. coli inactivation within the WW in the lab ranged from 0.09 day(-1) (d(-1)) at 7.6 degrees C to 0.18d(-1) at 22.8 degrees C. The average in situ rate constant observed within the domestic wetland ranged from 0.02 d(-1) to 0.03 d(-1) at an average water temperature of 17 degrees C. First order rate constants for E. coli inactivation within the DW ranged from 0.01 d(-1) at 7.7 degrees C to 0.04 d(-1) at 24.6 degrees C. Calculated distribution coefficients (K(d)) were 19,000 mL g(-1), 324,000 mL g(-1), and 293 mL g(-1) for E. coli with domestic septic tank effluent (STE), treated wetland effluent (WLE), and DW, respectively. Approximately 50%, 20%, and 90% of E. coli were "free floating" or associated with particles 5 microm within both the STE and DW, settling did not appear to contribute to E. coli removal within sedimentation experiments, indicating that the particles the bacteria were associated with had very small settling velocities. The results of this study highlight the

  11. The biogeography of fungal communities in wetland sediments along the Changjiang River and other sites in China

    National Research Council Canada - National Science Library

    Wu, Bing; Tian, Jianqing; Bai, Chunming; Xiang, Meichun; Sun, Jingzu; Liu, Xingzhong

    2013-01-01

    ...)) methods to assess the influence of historical and contemporary factors on the distributions of fungi in the wetland sediments at 10 locations along the Changjiang River and at 10 other locations in China...

  12. Redox geochemistry in organic-rich sediments of a constructed wetland treating colliery spoil leachate

    Energy Technology Data Exchange (ETDEWEB)

    Morrison, M.I.; Aplin, A.C. [University of Newcastle, Newcastle Upon Tyne (United Kingdom). School of Civil Engineering and Geoscience

    2009-01-15

    The results are reported of a geochemical study of sediment cores and surface waters taken over an annual cycle from the compost-based constructed wetland at Quaking Houses, NE England. The wetland was built to treat acidic and metalliferous waters emanating from colliery spoil. The influent waters contain up to 10 mM SO{sub 4}{sup 2-}, total Fe around 100 {mu} M, and a mean pH of 6.2. The organic-rich sediments sustain a coupled redox cycle of Fe and S which occurs throughout the year but which is more intense in the summer months. Throughout the sediments, reduction of Fe(III) and SO{sub 4}{sup 2-} apparently occur within the same macroscopic volume of sediment, along with oxidation of sulfide and Fe(III). Pore water pH is between 7.2 and 7.8 and alkalinity increases downwards, coupled to microbial SO{sub 4} and Fe reduction. Transport processes occurring at and across the sediment-water interface are sufficiently rapid in the similar to 20 h residence time of the waters to: (a) remove 70-90% of influent Fe and 15-25% of influent SO{sub 4} into surface sediments and (b) increase both the pH and alkalinity of effluent waters. Coupling of the Fe and S cycles is fundamental to effective remediation in terms of both alkalinity generation and the retention of metals.

  13. Diversity and composition of sediment bacteria in subtropical coastal wetlands of North Stradbroke Island, Queensland, Australia

    Science.gov (United States)

    Chuvochina, Maria; Sampayo, Eugenia; Welti, Nina; Hayes, Matthew; Lu, Yang; Lovelock, Catherine; Lockington, David

    2013-04-01

    Coastal wetlands provide a wide variety of important ecosystem services but continue to suffer disturbance, degradation and deforestation. Sediment bacteria are responsible for major nutrient transformation and recycling in these ecosystems. Insight into microbial community composition and the factors that determine them may improve our understanding of biogeochemical processes, food web dynamics, biodegradation processes and, thus, help to develop the management strategies for preserving the ecosystem health and services. Characterizing shifts in community taxa along environmental gradients has been shown to provide a useful tool for determining the major drivers affecting community structure and function. North Stradbroke Island (NSI) in Southern Queensland presents considerable habitat diversity including variety of groundwater dependent ecosystems such as lakes, swamps, sedge-like salt marshes and mangroves. Ecological responses of continuous groundwater extraction for municipal purposes and sand mining operations on NSI are still need to be assessed in order to protect its unique environment. Changes in coastal hydrology due to either climate change or human activity may directly affect microbial populations and, thus, biogeochemical cycles of nutrients. These may result in altering/losing some ecosystem services provided by coastal wetlands. In this study we examine microbial diversity and determine environmental controls on bacterial community structure along a natural transition from freshwater forested wetland (melaleuca woodland), sedge-like salt marsh and into mangroves located at NSI. The study area is characterized by significant groundwater flow, nutrient limitation and sharp transition from one ecosystem type to another. Sediment cores (0-5 cm and 20-25 cm depth) were collected from three representative sites of each zone (mangroves - salt marsh - freshwater wetland) along the salinity gradient in August 2012. Subsamples were set aside for use in

  14. Establishing a tracer-based sediment budget to preserve wetlands in Mediterranean mountain agroecosystems (NE Spain)

    Energy Technology Data Exchange (ETDEWEB)

    Navas, Ana, E-mail: anavas@eead.csic.es [Department of Soil and Water, Estación Experimental de Aula Dei, EEAD-CSIC, Avda. Montañana 1005, 50059 Zaragoza (Spain); López-Vicente, Manuel, E-mail: mvicente@eead.csic.es [Department of Soil and Water, Estación Experimental de Aula Dei, EEAD-CSIC, Avda. Montañana 1005, 50059 Zaragoza (Spain); Gaspar, Leticia, E-mail: leticia.gaspar@plymouth.ac.uk [School of Geography, Earth and Environmental Science, Plymouth University, Plymouth, Devon PL4 8AA (United Kingdom); Palazón, Leticia, E-mail: lpalazon@eead.csic.es [Department of Soil and Water, Estación Experimental de Aula Dei, EEAD-CSIC, Avda. Montañana 1005, 50059 Zaragoza (Spain); Quijano, Laura, E-mail: lquijano@eead.cisc.es [Department of Soil and Water, Estación Experimental de Aula Dei, EEAD-CSIC, Avda. Montañana 1005, 50059 Zaragoza (Spain)

    2014-10-15

    Mountain wetlands in Mediterranean regions are particularly threatened in agricultural environments due to anthropogenic activity. An integrated study of source-to-sink sediment fluxes was carried out in an agricultural catchment that holds a small permanent lake included in the European NATURA 2000 Network. More than 1000 yrs of human intervention and the variety of land uses pose a substantial challenge when attempting to estimate sediment fluxes which is the first requirement to protect fragile wetlands. To date, there have been few similar studies and those that have been carried out have not addressed such complex terrain. Geostatistical interpolation and GIS tools were used to derive the soil spatial redistribution from point {sup 137}Cs inventories, and to establish the sediment budget in a catchment located in the Southern Pyrenees. The soil redistribution was intense and soil erosion predominated over soil deposition. On the areas that maintained natural vegetation the median soil erosion and deposition rates were moderate, ranging from 2.6 to 6 Mg ha yr{sup −1} and 1.5 to 2.1 Mg ha yr{sup −1}, respectively. However, in cultivated fields both erosion and deposition were significantly higher (ca. 20 Mg ha yr{sup −1}), and the maximum rates were always associated with tillage practices. Farming activities in the last part of the 20th century intensified soil erosion, as evidenced by the 1963 {sup 137}Cs peaks in the lake cores and estimates from the sediment budget indicated a net deposition of 671 Mg yr{sup −1}. Results confirm a siltation risk for the lake and provide a foundation for designing management plans to preserve this threatened wetland. This comprehensive approach provides information useful for understanding processes that influence the patterns and rates of soil transfer and deposition within fragile Mediterranean mountain wetlands subjected to climate and anthropogenic stresses. - Highlights: • Soil erosion threatens long

  15. Suspended sediment fluxes in a tidal wetland: Measurement, controlling factors, and error analysis

    Science.gov (United States)

    Ganju, N.K.; Schoellhamer, D.H.; Bergamaschi, B.A.

    2005-01-01

    Suspended sediment fluxes to and from tidal wetlands are of increasing concern because of habitat restoration efforts, wetland sustainability as sea level rises, and potential contaminant accumulation. We measured water and sediment fluxes through two channels on Browns Island, at the landward end of San Francisco Bay, United States, to determine the factors that control sediment fluxes on and off the island. In situ instrumentation was deployed between October 10 and November 13, 2003. Acoustic Doppler current profilers and the index velocity method were employed to calculate water fluxes. Suspended sediment concentrations (SSC) were determined with optical sensors and cross-sectional water sampling. All procedures were analyzed for their contribution to total error in the flux measurement. The inability to close the water balance and determination of constituent concentration were identified as the main sources of error; total error was 27% for net sediment flux. The water budget for the island was computed with an unaccounted input of 0.20 m 3 s-1 (22% of mean inflow), after considering channel flow, change in water storage, evapotranspiration, and precipitation. The net imbalance may be a combination of groundwater seepage, overland flow, and flow through minor channels. Change of island water storage, caused by local variations in water surface elevation, dominated the tidalty averaged water flux. These variations were mainly caused by wind and barometric pressure change, which alter regional water levels throughout the Sacramento-San Joaquin River Delta. Peak instantaneous ebb flow was 35% greater than peak flood flow, indicating an ebb-dominant system, though dominance varied with the spring-neap cycle. SSC were controlled by wind-wave resuspension adjacent to the island and local tidal currents that mobilized sediment from the channel bed. During neap tides sediment was imported onto the island but during spring tides sediment was exported because the main

  16. Magntic susceptibility as a proxy to heavy metal content in the sediments of Anzali wetland, Iran

    Directory of Open Access Journals (Sweden)

    Naseh Mohammad Reza Vesali

    2012-12-01

    Full Text Available Abstract Heavy metal concentrations and magnetic susceptibility of sediment samples were analyzed as indicators of urban and industrial contamination in Anzali wetland in Gilan, Iran. The aim was to investigate the suitability of magnetic properties measurements for indicating heavy metal pollution. The concentration of six heavy metals (Ni, Cr, Cd, Zn, Fe, and Pb was determined in different depths of four sediment core samples within four different regions of the wetland (Abkenar, Hendekhaleh, Shijan and Siakeshim. Average concentration of heavy metals in the sediment cores was higher than the severe effect level (SEL for Ni, Cr and Fe (77.26, 113.63 ppm and 5.2%, respectively and lower than SEL for Cd, Zn and Pb (0.84, 137.7, 29.77 ppm, respectively. It was found that the trend of metal concentrations with the depth is different in each core and is related to the pollution discharges into the rivers entering the wetland. Core magnetic susceptibility measurements also showed different magnetic properties in each core. Cluster analysis was applied using Pearson correlation coefficient between heavy metal concentrations and magnetic properties across each core. Significant relationship was found to exist between magnetic susceptibility and the concentration of Ni in Abkenar and the concentration of Fe in other regions. Whereas Abkenar is almost the isolated and uncontaminated region of the wetland, it revealed a difference in magnetic properties between contaminated and uncontaminated sediments. It was concluded that magnetic properties of samples from contaminated zone were mostly related to Fe content. The result of this study demonstrated that magnetic susceptibility measurements could be applied as a proxy method for heavy metal pollution determination in marine environments in Iran especially as a rapid and cost-effective introductory site assessments.

  17. Establishing a tracer-based sediment budget to preserve wetlands in Mediterranean mountain agroecosystems (NE Spain).

    Science.gov (United States)

    Navas, Ana; López-Vicente, Manuel; Gaspar, Leticia; Palazón, Leticia; Quijano, Laura

    2014-10-15

    Mountain wetlands in Mediterranean regions are particularly threatened in agricultural environments due to anthropogenic activity. An integrated study of source-to-sink sediment fluxes was carried out in an agricultural catchment that holds a small permanent lake included in the European NATURA 2000 Network. More than 1000 yrs of human intervention and the variety of land uses pose a substantial challenge when attempting to estimate sediment fluxes which is the first requirement to protect fragile wetlands. To date, there have been few similar studies and those that have been carried out have not addressed such complex terrain. Geostatistical interpolation and GIS tools were used to derive the soil spatial redistribution from point (137)Cs inventories, and to establish the sediment budget in a catchment located in the Southern Pyrenees. The soil redistribution was intense and soil erosion predominated over soil deposition. On the areas that maintained natural vegetation the median soil erosion and deposition rates were moderate, ranging from 2.6 to 6 Mg ha yr(-1) and 1.5 to 2.1 Mg ha yr(-1), respectively. However, in cultivated fields both erosion and deposition were significantly higher (ca. 20 Mg ha yr(-1)), and the maximum rates were always associated with tillage practices. Farming activities in the last part of the 20th century intensified soil erosion, as evidenced by the 1963 (137)Cs peaks in the lake cores and estimates from the sediment budget indicated a net deposition of 671 Mg yr(-1). Results confirm a siltation risk for the lake and provide a foundation for designing management plans to preserve this threatened wetland. This comprehensive approach provides information useful for understanding processes that influence the patterns and rates of soil transfer and deposition within fragile Mediterranean mountain wetlands subjected to climate and anthropogenic stresses. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Investigation on concentration of elements in wetland sediments and aquatic plants

    OpenAIRE

    H. Janadeleh; A. Hosseini Alhashemi; S.M.B. Nabavi

    2016-01-01

    The major aim of the present study was to investigate element (Fe, Ni, Pb, V, Zn) concentrations in sediment and different tissues of Phragmities australis and Typha latifolia in Hor al-Azim Wetland Southwest Iran. Sampling of sediments and aquatic plants was carried out during spring and summer 2014. Results showed that the mean  concentrations of elements in Phragmities australis  in root and stem-leaf were as follows: Iron:4448 mg/kg, Nickel: 28 mg/kg, Lead:8 mg/kg, Vanadium:10 mg/kg  and ...

  19. Incorporating H2 Dynamics and Inhibition into a Microbially Based Methanogenesis Model for Restored Wetland Sediments

    Science.gov (United States)

    Pal, David; Jaffe, Peter

    2015-04-01

    Estimates of global CH4 emissions from wetlands indicate that wetlands are the largest natural source of CH4 to the atmosphere. In this paper, we propose that there is a missing component to these models that should be addressed. CH4 is produced in wetland sediments from the microbial degradation of organic carbon through multiple fermentation steps and methanogenesis pathways. There are multiple sources of carbon for methananogenesis; in vegetated wetland sediments, microbial communities consume root exudates as a major source of organic carbon. In many methane models propionate is used as a model carbon molecule. This simple sugar is fermented into acetate and H2, acetate is transformed to methane and CO2, while the H2 and CO2 are used to form an additional CH4 molecule. The hydrogenotrophic pathway involves the equilibrium of two dissolved gases, CH4 and H2. In an effort to limit CH4 emissions from wetlands, there has been growing interest in finding ways to limit plant transport of soil gases through root systems. Changing planted species, or genetically modifying new species of plants may control this transport of soil gases. While this may decrease the direct emissions of methane, there is little understanding about how H2 dynamics may feedback into overall methane production. The results of an incubation study were combined with a new model of propionate degradation for methanogenesis that also examines other natural parameters (i.e. gas transport through plants). This presentation examines how we would expect this model to behave in a natural field setting with changing sulfate and carbon loading schemes. These changes can be controlled through new plant species and other management practices. Next, we compare the behavior of two variations of this model, with or without the incorporation of H2 interactions, with changing sulfate, carbon loading and root volatilization. Results show that while the models behave similarly there may be a discrepancy of nearly

  20. Mineral provinces and matter provenance of the surficial sediments in the western Philippine Sea: implication for modern sedimentation in West Pacific marginal basin

    Institute of Scientific and Technical Information of China (English)

    REN Xiangwen; YAN Quanshu; SHI Xuefa; WANG Kunshan; JIANG Xiaoli

    2007-01-01

    The characteristics and distribution patterns of detrital minerals (0.063~0.125 mm) in marine sediments provide a significant indicator for the identification of the origin of sediment.The detrital mineral composition of 219 surface sediment samples was analysed to identify the distribution of sediments within the western Philippine Sea. The area can be divided into three mineral provinces: (Ⅰ) province east of the Philippine Trench, the detrital minerals in this province are mainly composed of calcareous or siliceous organisms, with the addition of volcanogenic minerals from an adjacent island arc; (Ⅱ) middle mineral province, clastic minerals including feldspar, quartz and colorless volcanic glass, sourced from seamounts with intermediate-acid volcanic rock, or erupting intermediate-acid volcano; (Ⅲ) province west of the Palau-Kyūshū Ridge, the matter provenance within this province is complex; the small quantity of feldspar and quartz may be sourced from seamounts or erupting volcano with intermediate-acid composition, with a component of volcanic scoria sourced from a volcano erupting on the Palau-Kyūshū Ridge. it is suggested that, (1) Biogenic debris of the study area is closely related to water depth, with the amount of biogenic debris controlled by carbonate lysocline. (2) Volcaniclastic matter derived from the adjacent island arc can be entrained by oceanic currents and transported towards the abyssal basin over a short distance. The weathering products of volcanic rocks of the submarine plateau (e.g.,Benham Plateau) and adjacent ridges provide an important source of detrital sedimentation, and the influence scope of them is constrained by the intensity of submarine weathering. (3) Terrigenous sediments from the continent of Asia and the adjacent Philippine island arc have little influence on the sedimentation of this study area, and the felsic mineral component is probably sourced from volcanic seamounts of intermediate-acid composition.

  1. Investigation on Fe, Mn, Zn, Cu, Pb and Cd fractions in the natural surface coating samples and surficial sediments in the Songhua River, China

    Institute of Scientific and Technical Information of China (English)

    GUO Shu-hai; WANG Xiao-li; LI YU; CHEN Jie-jiang; YANG Jun-cheng

    2006-01-01

    Natural surface coating samples (NSCSs) from the surface of shingles and surficial sediments (SSs) in the Songhua River,China were employed to investigate the relationship between NSCSs and SSs in fractions of heavy metals (Fe, Mn, Zn, Cu, Pb, and Cd) using the modified sequential extraction procedure (MSEP). The results show that the differences between NSCSs and SSs in Fe fractions were insignificant and Fe was dominantly present as residual phase (76.22% for NSCSs and 80.88% for SSs) and Fe-oxides phase (20.33% for NSCSs and 16.15% for SSs). Significant variation of Mn distribution patterns between NSCSs and SSs was observed with Mn in NSCSs mainly present in Mn-oxides phase (48.27%) and that in SSs present as residual phase (45.44%). Zn, Cu,Pb and Cd were found dominantly in residual fractions (>48%), and next in solid oxides/hydroxides for Zn, Pb and Cd and in easily oxidizable solids/compounds form for Cu, respectively. The heavy metal distribution patterns implied that Fe/Mn oxides both in NSCSs and SSs were more important sinks for binding and adsorption of Zn, Pb and Cd than organic matter (OM), and inversely,higher affinity of Cu to OM than Fe/Mn oxides in NSCSs and SSs was obtained. Meanwhile, it was found that the distributions of heavy metals in NSCSs and SSs were similar to each other and the pseudo-total concentrations of Zn, Cu, Pb and Cd in NSCSs were greater than those in SSs, highlighting the more importance for NSCSs than SSs in controlling behaviours of heavy metals in aquatic environments.

  2. A remote sensing approach for connecting the historic 2011 Mississippi River flood to wetland sedimentation on the Delta

    Science.gov (United States)

    Falcini, Federico; Colella, Simone; Volpe, Gianluca; Khan, Nicole; Macelloni, Leonardo; Santoleri, Rosalia; Horton, Benjamin; Jerolmack, Douglas

    2013-04-01

    Wetlands in the Mississippi River deltaic plain are deteriorating in part because levees and control structures starve them of sediment. In Spring of 2011 a record breaking flood brought discharge on the lower Mississippi River to dangerous levels, forcing managers to divert additional water to the adjacent Atchafalaya River Basin. Here we quantify differences between the Mississippi and Atchafalaya River inundation and sediment-plume patterns using field-calibrated satellite data, and assess the impact these outflows had on wetland sedimentation. Since standard products available from MyOcean were not suitable for this purpose an ad hoc processing was developed to establish a relationship between field suspended sediment concentration (SSC) data and the corrected MODIS reflectance at 645 nm. We show that the focused, high-momentum jet from the leveed Mississippi delivered sediment far offshore. In contrast, the plume from the Atchafalaya was more diffuse; diverted water inundated a large area, and sediment was trapped within the coastal current. Maximum sedimentation (up to several centimetres) occurred in the Atchafalaya Basin despite the larger sediment load carried by the Mississippi. Little accumulation occurred along the shoreline between these river sources. The correspondence between zones of high shoreline deposition, and coastal SSC patterns indentified from satellite data, is strongly suggestive of plume-derived deposition on marshes. Our findings allow us to set an hydrodynamic theory that provides a mechanistic link between river-mouth dynamics and wetland sedimentation patterns, which is relevant for plans to restore deltaic wetlands.

  3. Distribution pattern of trace metal pollutants in the sediments of an urban wetland in the southwest coast of India

    Directory of Open Access Journals (Sweden)

    Harikumar P.S,

    2010-05-01

    Full Text Available A study was carried out to invstigate the concentrations and spatial distribution of trace metals in the sediments of Kottuli Wetland,whuich is in the south west coast of India Eight stations were strategically positioned along the length of wetland and sampled for trace metals (Cu, Mn, Cd, Ni, Pb, Zn &Cr content. From the analysis, it was observed that the mean concentration of all the analysed trace metals exceeded the average world wide shale concentrations and average Japanese river sediment values. Pollution load index value (PLI of the studied area ranged from 0.10 to 58.78 which indicated that the wetland sediments were polluted. From the study, PLI of the downstream area of the wetland had the highest values of Cu, Mn, Cd, Zn & Cr. According to the index of Geoaccumulation, Igeo, all the sampling stations may face a severe trace metal pollution contamination problem in the future.

  4. Modeling the Interaction of H2 on Root Exudate Degradation and Methanogenesis in Wetland Sediments

    Science.gov (United States)

    Pal, D. S.; Jaffe, P. R.

    2014-12-01

    CH4 is produced in wetland sediments from the microbial degradation of organic carbon through multiple fermentation steps and methanogenesis pathways. There are many potential sources of carbon for methananogenesis; in vegetated wetland sediments, microbial communities consume root exudates as a major source of organic carbon. In many methane models propionate is used as a model carbon molecule. This simple sugar is fermented into acetate and H2, acetate is transformed to methane and CO2 while the H2 and CO2 is synthesized to form an additional CH4 molecule. The hydrogenotrophic pathway involves the equilibrium of two dissolved gases, CH4 and H2. In an effort to limit CH4 emissions from wetlands, there has been growing interest in finding ways to limit plant transport of soil gases through root systems. While this may decrease the direct emissions of methane, there is little understanding about how H2 dynamics may feedback into overall methane production. Since H2 is used in methane production and produced in propionate fermentation, increased subsurface H2 concentrations can simultaneously inhibit propionate fermentation and acetate production and enhance hydrogenotrophic methanogenesis. For this study, we incubated soil samples from vegetated wetland sediments with propionate or acetate and four different hydrogen concentrations. The headspaces from these incubations were simultaneously analyzed for H2 and CH4 at multiple time points over two months. The comparison of methane production between different hydrogen concentrations and different carbon sources can indicate which process is most affected by increased hydrogen concentrations. The results from this study were combined with a newly formulated steady-state model of propionate degradation and formation of methane, that also accounts for the venting off both gases via plants. The resulting model indicates how methane production and emissions would be affected by plant volatilization.

  5. Use of Sediment Quality Guidelines and pollution indicators for the assessment of heavy metal and PAH contamination in Greek surficial sea and lake sediments.

    Science.gov (United States)

    Hahladakis, John; Smaragdaki, Eleftheria; Vasilaki, Georgia; Gidarakos, Evangelos

    2013-03-01

    Eight different surface sediment samples (K1-K8) were collected from two separate areas of Lake Koumoundourou and two samples (E1 and E2) from one area of Elefsis Bay, Athens, Greece. The level of pollution attributed to heavy metals was evaluated using several pollution indicators. Degree of Contamination, Modified Contamination Degree and Geoaccumulation Indexes were applied in order to determine and assess the anthropogenic contribution of the selected six elements (Cr, Ni, Cu, Zn, As and Pb). Moreover, the adverse effects of the sediments to aquatic organisms, from both heavy metals and polycyclic aromatic hydrocarbons (PAHs), were determined by using Sediment Quality Guidelines. The results indicated that Lake Koumoundourou is contaminated with heavy metals in a moderate degree and almost 50 % of the sediments are associated with frequent observation of adverse effects, when it comes to Ni and occasional observation of adverse effects, when it comes to Cu, Zn and Pb. As far as PAHs are concerned, around 60 % of the samples can be occasionally associated to toxic biological effects according to the effect-range classification for phenanthrene, benzo(a)anthracene, chrysene and pyrene. Finally, samples taken from the north side of the lake are more contaminated with PAHs than the ones taken from the east side probably due to the existence of the water barrier which acts as a reservoir of PAHs.

  6. Phosphorus fractionation and distribution in sediments from wetlands and canals of a water conservation area in the Florida Everglades

    Science.gov (United States)

    Qingren Wang; Yuncong Li; Ying. Ouyang

    2011-01-01

    Phosphorus (P) fractionation and distribution in sediments are of great concern in the Florida Everglades ecosystem because potential eutrophication of surface waters usually results from P external loading and stability. Intact core sediment samples were collected to a depth of 35 cm from wetlands and canals across Water Conservation Area 3 (WCA‐3) of the Florida...

  7. Amending soils with sediment material from constructed wetlands increases phosphorus sorption

    Science.gov (United States)

    Laakso, Johanna; Uusitalo, Risto; Leppänen, Janette; Yli-Halla, Markku

    2017-04-01

    Sediment of agricultural constructed wetlands (CWs) is comprised of matter eroded from surrounding fields. This material is rich in aluminium (Al) and iron (Fe) (hydr)oxides that have a high affinity for phosphorus (P). Sediment material returned to fields could therefore affect soil P retention characteristics. We incubated a clay soil with a high soil test P (STP, 24 mg PAc l-1; extracted with pH 4.65 ammonium acetate buffer) and a sandy loam with excessive STP (210 mg PAc l-1) for three weeks with increasing amounts of CW sediment: 0, 2, 5, 10 and 50% of the sample volume. After incubation, the soil-sediment mixtures were studied with the quantity/intensity (Q/I) technique, using chemical extractions and by exposing the mixtures to simulated rainfall. Sorption affinity for P regularly increased with increasing the sediment share of the mixtures, the 0% sediment content having the lowest and 50% sediment content the highest P sorption. With 0% sediment application, the value of equilibrium P concentration (EPC0) determined by Q/I technique, was 0.69 and 44.3 mg l-1 for clay soil and sandy loam, respectively. With 2-5% sediment amendment, the EPC0 decreased 13-36% for clay soil and 13-54% for sandy loam. The 50% sediment mixtures had EPC0 of 0.05 mg l-1 for both soils. At a practically feasible sediment addition rate of 5%, dissolved reactive P (DRP) in percolating water from simulated rainfall decreased by 55% in the clay soil and 54% in sandy loam (p<0.001 in both cases). Particulate-P (PP) also showed a decreasing trend with increasing sediment addition rate. Upon prolonged simulated rainfall, the decreasing effect of sediment on DRP and PP declined somewhat. The effects of sediment addition can be attributed partly to increased salt concentrations in the sediment, which have a short-term effect on P mobilisation, but mostly to increased concentrations of Al and Fe (hydr)oxides, increasing long-term P sorption capacity. Amending the soils with sediment material

  8. Influence of plants on the reduction of hexavalent chromium in wetland sediments

    Energy Technology Data Exchange (ETDEWEB)

    Zazo, Juan A. [Department of Chemical Engineering, Universidad Autonoma de Madrid, Madrid, 28049 (Spain)], E-mail: juan.zazo@uam.es; Paull, Jeffery S.; Jaffe, Peter R. [Department of Civil and Environmental Engineering, Princeton University, Princeton, NJ 08544 (United States)

    2008-11-15

    This work addresses the effect that plants (Typha latifolia and Carex lurida) have on the reduction of Cr(VI) in wetland sediments. Experiments were carried out using tubular microcosms, where chemical species were monitored along the longitudinal flow axis. Cr(VI) removal was enhanced by the presence of plants. This is explained by a decrease in the redox potential promoted by organic root exudates released by plants. Under these conditions sulfate reduction is enhanced, increasing the concentration of sulfide species in the sediment pore water, which reduce Cr(VI). Evapotranspiration induced by plants also contributed to enhance the reduction of Cr(VI) by concentrating all chemical species in the sediment pore water. Both exudates release and evapotranspiration have a diurnal component that affects Cr(VI) reduction. Concentration profiles were fitted to a kinetic model linking sulfide and Cr(VI) concentrations corrected for evapotranspiration. This expression captures both the longitudinal as well as the diurnal Cr(VI) concentration profiles. - The presence of plants enhances the reduction of Cr(VI) in wetland sediments by modifying the governing biogeochemical cycle.

  9. Spatial distribution and ecological risk assessment of metals in sediments of Baiyangdian wetland ecosystem.

    Science.gov (United States)

    Su, Liya; Liu, Jingling; Christensen, Per

    2011-07-01

    Although there are many studies of heavy metal contaminations of sediments, attention has seldom been paid to the problem in developing countries. The purpose of this article is to find the distribution and ecological risk of As, Hg, Cr, Cd, Pb, Cu, and Zn in surface sediment of Baiyangdian which is the biggest wetland in Northeast China. We apply three methodologies. The first is literature analysis comparing total concentrations of heavy metals with other water bodies around world. The second is Chinese Environmental Quality Standard for Soils (EQSS), National Environmental Protection Agency of China 1995, and the third is Soil and Aquatic Sediment Guidelines and Standards issued by New York Department of Environmental Conservation (NYSDEC). The results show that compared to other water bodies around the world, the seven heavy metals are low. However, Cd was found in the most polluting level of EQSS near a village and was second grade some distance from it. The village was also the most polluted site of Zn, which was in the second grade. When assessed by NYSDEC, Cu, Cr, and As contaminated the sediment and with moderate impacts on benthic life while Pb, Hg, and Zn were found at tolerable levels throughout Baiyangdian. The centre of Cu and Cr contamination was also near the village. As is the most polluting heavy metals with a major occurrence in the middle of the wetland. There were no heavy metals creating severe disturbance to the benthic communities. Based on the assessment, this article proposes different options for more sustainable management.

  10. Spatial distribution and ecological risk assessment of metals in sediments of Baiyangdian wetland ecosystem

    DEFF Research Database (Denmark)

    Su, Liya; Liu, Jingling; Christensen, Per

    2011-01-01

    is the biggest wetland in Northeast China. We apply three methodologies. The first is literature analysis comparing total concentrations of heavy metals with other water bodies around world. The second is Chinese Environmental Quality Standard for Soils (EQSS), National Environmental Protection Agency of China......Although there are many studies of heavy metal contaminations of sediments, attention has seldom been paid to the problem in developing countries. The purpose of this article is to find the distribution and ecological risk of As, Hg, Cr, Cd, Pb, Cu, and Zn in surface sediment of Baiyangdian which...... 1995, and the third is Soil and Aquatic Sediment Guidelines and Standards issued by New York Department of Environmental Conservation (NYSDEC). The results show that compared to other water bodies around the world, the seven heavy metals are low. However, Cd was found in the most polluting level...

  11. Behavior of some heavy metal in sediments of the protected wetland Sebkha El Kelbia (Tunisia)

    Science.gov (United States)

    Khedhiri, S.; Gueddari-Darragi, F.; Duplay, J.

    2003-04-01

    Sebkha El Kelbia is a vast lagoon located at the center of Tunisia between the towns of Sousse and Kairouan. It is considered as the second most significant wetland in Tunisia. Few studies were interested in the problem of pollution in this lagoon, especially in heavy metals. This work is a first geochemical study of surface sediments in the sebkha. The aim is to assess the possible pollution by heavy metals (Zn, Pb, Cu, Cd and Ni), and to determine by correlative studies the phases carrying these elements. The analyses of the trace elements were carried out by atomic absorption spectrometry (Philips) after crushing of the sediment and acid attacks. The mineralogical composition of the sediment was obtained by X-Ray diffractometry (Siemens). The distribution of Zn, Pb, Cu, Cd and Ni in surface sediments was established and a moderate contamination by Pb and Cd could be pointed out by frequency distribution calculations. There is also a clear positive correlation between the rate of Cu, Zn, Pb and Ni, and the amount of clay in the sediment. This shows that clay minerals may preferentially carry these elements. Cd shows a different behavior with respect to clay minerals and is rather bound to carbonates. (Khedhiri et al. 2001; Khedhiri 1998). References : Khedhiri S., Darragi-Gueddari F., Duplay J. (2001) : Heavy Metal Distribution In Surface Sediments Of The Protected Wetland El Kelbia (Tunisia): Environmental Mineralogy and geochemistry. EUG XI, Strasbourg, 8th-12th April 2001. Khedhiri S. (1998) : L’écosystème de la sebkha El Kelbia : caractérisation géochimique des eaux et des sédiments superficiels. Mémoire de DEA, Université de Tunis II, 115 p.

  12. Ecological Risk Assessment of Metals Contamination in the Sediments of Natural Urban Wetlands in Dry Tropical Climate.

    Science.gov (United States)

    Rana, Vivek; Maiti, Subodh Kumar; Jagadevan, Sheeja

    2016-09-01

    The pollution load due to metal contamination in the sediments of urban wetlands (Dhanbad, India) due to illegal release of domestic and industrial wastewater was studied by using various geochemical indices, such as contamination factor (Cf), degree of contamination (Cd), modified degree of contamination (mCd), pollution load index (PLI) and geoaccumulation index (Igeo) for Cu, Co, Cd, Cr and Mn. Cluster analysis (CA) and Principal component analysis (PCA) of metals present in wetland sediments were carried out to assess their origin and relationship with each other. The Cf values for different metals in the wetlands under investigation indicated low to very high level of pollution (Cf ranged between 0.02 and 14.15) with highest Cf (14.15) for Cd. The wetland receiving both domestic and industrial wastewater had the highest values of Cd, mCd and PLI as 17.48, 3.49 and 1.03 respectively.

  13. 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.

  14. The Risk Assessment of Sediment Heavy Metal Pollution in the East Dongting Lake Wetland

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    Cong Hu

    2015-01-01

    Full Text Available Total concentrations of cadmium (Cd, lead (Pb, chrome (Cr, and nickel (Ni in surface sediment (0–10 cm from the East Dongting Lake wetlands were determined and the spatial distribution of heavy metals was mapped. The results showed that the single risk indices (Eri of heavy metals were ranked in the order of Cd > Pb > Ni > Cr. The content of Cd and Pb was gradually reduced from the east (Xiangjiang River to the west, while the Cr and Ni content had a patchy distribution pattern in the East Dongting Lake wetlands. Cd and Pb contents were correlated with soil pH significantly, while Cr and Ni contents were correlated with soil organic carbon (SOC and total nitrogen (TN. The origination of heavy metal (Cd, Cr, Ni, and Pb could be divided into two groups: Cd and Pb from anthropogenic source and Cr and Ni from parent material weathering. Our results indicated that Cd posed a high risk to local ecosystem. The relatively lower pH and higher soil organic carbon (SOC and total nitrogen (TN in sediment may inhibit the fixation of heavy metals, which in turn increased the concentration of heavy metal in sediment.

  15. Effects of drain-fill cycling on chlorpyrifos mineralization in wetland sediment-water microcosms.

    Science.gov (United States)

    Gebremariam, Seyoum Yami; Beutel, Marc W

    2010-03-01

    Constructed treatment wetlands are efficient at retaining a range of pesticides, however the ultimate fate of many of these compound is not well understood. This study evaluated the effect of drain-fill cycling on the mineralization of chlorpyrifos, a commonly used organophosphate insecticide, in wetland sediment-water microcosms. Monitoring of the fate of (14)C ring-labeled chlorpyrifos showed that drain-fill cycling resulted in significantly lower mineralization rates relative to permanently flooded conditions. The reduction in mineralization was linked to enhanced partitioning of the pesticide to the sediment phase, which could potentially inhibit chlorpyrifos hydrolysis and mineralization. Over the nearly two-month experiment, less than 2.5% of the added compound was mineralized. While rates of mineralization in this experiment were higher than those reported for other soils and sediments, their low magnitude underscores how persistent chlorpyrifos and its metabolites are in aquatic environments, and suggests that management strategies and ecological risk assessment should focus more on ultimate mineralization rather than the simple disappearance of the parent compound.

  16. Mercury in sediment, water, and fish in a managed tropical wetland-lake ecosystem.

    Science.gov (United States)

    Malczyk, Evan A; Branfireun, Brian A

    2015-08-15

    Mercury pollution has not been well documented in the inland lakes or fishes of Mexico, despite the importance of freshwater fish as a source of protein in local diets. Total mercury and methylmercury in waters, sediments, and the commercial fish catch were investigated in Lake Zapotlán, Mexico. Concentrations of total and methylmercury were very high in runoff and wastewater inputs, but very low in sediments and surface waters of the open water area of the lake. Concentrations of total mercury in tilapia and carp were very low, consistent with the low concentrations in lake water and sediments. Particle settling, sorption, the biogeochemical environment, and/or bloom dilution are all plausible explanations for the significant reductions in both total mercury and methylmercury. Despite very high loading of mercury, this shallow tropical lake was not a mercury-impaired ecosystem, and these findings may translate across other shallow, alkaline tropical lakes. Importantly, the ecosystem services that seemed to be provided by peripheral wetlands in reducing mercury inputs highlight the potential for wetland conservation or restoration in Mexico.

  17. Combined influence of sedimentation and vegetation on the soil carbon stocks of a coastal wetland in the Changjiang estuary

    Science.gov (United States)

    Zhang, Tianyu; Chen, Huaipu; Cao, Haobing; Ge, Zhenming; Zhang, Liquan

    2016-08-01

    Coastal wetlands play an important role in the global carbon cycle. Large quantities of sediment deposited in the Changjiang (Yangtze) estuary by the Changjiang River promote the propagation of coastal wetlands, the expansion of saltmarsh vegetation, and carbon sequestration. In this study, using the Chongming Dongtan Wetland in the Changjiang estuary as the study area, the spatial and temporal distribution of soil organic carbon (SOC) stocks and the influences of sedimentation and vegetation on the SOC stocks of the coastal wetland were examined in 2013. There was sediment accretion in the northern and middle areas of the wetland and in the Phragmites australis marsh in the southern area, and sediment erosion in the Scirpus mariqueter marsh and the bare mudflat in the southern area. More SOC accumulated in sediments of the vegetated marsh than in the bare mudflat. The total organic carbon (TOC) stocks increased in the above-ground biomass from spring to autumn and decreased in winter; in the below-ground biomass, they gradually increased from spring to winter. The TOC stocks were higher in the below-ground biomass than in the above-ground biomass in the P. australis and Spartina alterniflora marshes, but were lower in the below-ground biomass in S. mariqueter marsh. Stocks of SOC showed temporal variation and increased gradually in all transects from spring to winter. The SOC stocks tended to decrease from the high marsh down to the bare mudflat along the three transects in the order: P. australis marsh > S. alterniflora marsh > S. mariqueter marsh > bare mudflat. The SOC stocks of the same vegetation type were higher in the northern and middle transects than in the southern transect. These results suggest that interactions between sedimentation and vegetation regulate the SOC stocks in the coastal wetland in the Changjiang estuary.

  18. Distribution of Organic Carbon in the Sediments of Xinxue River and the Xinxue River Constructed Wetland, China.

    Science.gov (United States)

    Cao, Qingqing; Wang, Renqing; Zhang, Haijie; Ge, Xiuli; Liu, Jian

    2015-01-01

    Wetland ecosystems are represented as a significant reservoir of organic carbon and play an important role in mitigating the greenhouse effect. In order to compare the compositions and distribution of organic carbon in constructed and natural river wetlands, sediments from the Xinxue River Constructed Wetland and the Xinxue River, China, were sampled at two depths (0-15 cm and 15-25 cm) in both upstream and downstream locations. Three types of organic carbon were determined: light fraction organic carbon, heavy fraction organic carbon, and dissolved organic carbon. The results show that variations in light fraction organic carbon are significantly larger between upstream and downstream locations than they are between the two wetland types; however, the opposite trend is observed for the dissolved organic carbon. There are no significant differences in the distribution of heavy fraction organic carbon between the discrete variables (e.g., between the two depths, the two locations, or the two wetland types). However, there are significant cross-variable differences; for example, the distribution patterns of heavy fraction organic carbon between wetland types and depths, and between wetland types and locations. Correlation analysis reveals that light fraction organic carbon is positively associated with light fraction nitrogen in both wetlands, while heavy fraction organic carbon is associated with both heavy fraction nitrogen and the moisture content in the constructed wetland. The results of this study demonstrate that the constructed wetland, which has a relatively low background value of heavy fraction organic carbon, is gradually accumulating organic carbon of different types, with the level of accumulation dependent on the balance between carbon accumulation and carbon decomposition. In contrast, the river wetland has relatively stable levels of organic carbon.

  19. Distribution of Organic Carbon in the Sediments of Xinxue River and the Xinxue River Constructed Wetland, China.

    Directory of Open Access Journals (Sweden)

    Qingqing Cao

    Full Text Available Wetland ecosystems are represented as a significant reservoir of organic carbon and play an important role in mitigating the greenhouse effect. In order to compare the compositions and distribution of organic carbon in constructed and natural river wetlands, sediments from the Xinxue River Constructed Wetland and the Xinxue River, China, were sampled at two depths (0-15 cm and 15-25 cm in both upstream and downstream locations. Three types of organic carbon were determined: light fraction organic carbon, heavy fraction organic carbon, and dissolved organic carbon. The results show that variations in light fraction organic carbon are significantly larger between upstream and downstream locations than they are between the two wetland types; however, the opposite trend is observed for the dissolved organic carbon. There are no significant differences in the distribution of heavy fraction organic carbon between the discrete variables (e.g., between the two depths, the two locations, or the two wetland types. However, there are significant cross-variable differences; for example, the distribution patterns of heavy fraction organic carbon between wetland types and depths, and between wetland types and locations. Correlation analysis reveals that light fraction organic carbon is positively associated with light fraction nitrogen in both wetlands, while heavy fraction organic carbon is associated with both heavy fraction nitrogen and the moisture content in the constructed wetland. The results of this study demonstrate that the constructed wetland, which has a relatively low background value of heavy fraction organic carbon, is gradually accumulating organic carbon of different types, with the level of accumulation dependent on the balance between carbon accumulation and carbon decomposition. In contrast, the river wetland has relatively stable levels of organic carbon.

  20. Wetland response to sedimentation and nitrogen loading: diversification and inhibition of nitrogen-fixing microbes.

    Science.gov (United States)

    Moseman-Valtierra, S M; Armaiz-Nolla, K; Levin, L A

    2010-09-01

    Anthropogenic inputs of nutrients and sediment simultaneously impact coastal ecosystems, such as wetlands, especially during storms. Independent and combined effects of sediment and ammonium nitrate loading on nitrogen fixation rates and diversity of microbes that fix nitrogen (diazotrophs) were tested via field manipulations in Spartina foliosa and unvegetated zones at Tijuana Estuary (California, USA). This estuary is subject to episodic nitrogen enrichment and sedimentation associated with rain-driven flooding and slope instabilities, the latter of which may worsen as the Triple Border Fence is constructed along the U.S.-Mexico border. Responses of diazotrophs were assessed over 17 days using acetylene reduction assays and genetic fingerprinting (terminal restriction fragment length polymorphism [T-RFLP]) of nifH, which codes for dinitrogenase reductase. Sulfate-reducing bacteria performed approximately 70% of nitrogen fixation in Spartina foliosa rhizospheres in the absence of nitrogen loading, based on sodium molybdate inhibitions in the laboratory. Following nutrient additions, richness (number of T-RFs [terminal restriction fragments]) and evenness (relative T-RF fluorescence) of diazotrophs in surface sediments increased, but nitrogen fixation rates decreased significantly within 17 days. These responses illustrate, within a microbial community, conformance to a more general ecological pattern of high function among assemblages of low diversity. Diazotroph community composition (T-RF profiles) and rhizosphere diversity were not affected. Pore water ammonium concentrations were higher and more persistent for 17 days in plots receiving sediment additions (1 cm deep), suggesting that recovery of diazotroph functions may be delayed by the combination of sediment and nutrient inputs. Nitrogen fixation constitutes a mechanism for rapid transfer of fixed N to S. foliosa roots and a variety of primary consumers (within 3 and 8 days, respectively), as determined via

  1. COMPARISON OF HEAVY METAL CONCENTRATIONS IN SURFACE SEDIMENT OF TANJUNG PIAI WETLAND WITH OTHER SITES RECEIVING ANTHROPOGENIC INPUTS ALONG THE SOUTHWESTERN COAST OF PENINSULAR MALAYSIA

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Tanjung Piai wetland has now been proclaimed to be a wetland of international importance since 2003. Therefore, its heavy metal pollution status should be known and recorded. In this study, sediments in Tanjung Piai wetland were collected in 2002 and 2005 and were analysed for Cd, Cu, Ni, Pb and Zn. For comparison purpose, sediments were also collected for metal analysis from a known polluted site at Kg. Pasir Puteh, four jetties and a river. A comparison with the polluted sediment collected from Kg. Pasir Puteh and the established Sediment Quality Criteria showed that Tanjung Piai was not polluted with Cd, Cu, Ni, Pb and Zn. These background concentrations or baseline data of heavy metals in the sediment is important for future reference. Therefore, Tanjung Piai wetland is a suitable site for sanctuary and wetland conservation and it should be conserved for its pristine conditions in order to support its high biodiversity.

  2. Contrasting factors controlling microbial respiratory activity in the sediment of two adjacent Mediterranean wetlands.

    Science.gov (United States)

    de Vicente, Inmaculada; Amores, Victoria; Guerrero, Francisco; Cruz-Pizarro, Luis

    2010-07-01

    Electron transport system (ETS) activity of sediments as an indication of microbial metabolic activity was examined in two adjacent Mediterranean wetlands (southern Spain). We determined the spatio-temporal variation in ETS, and we explored the potential biological [organic matter (OM), chlorophyll a (Chl a), aerobic and anaerobic bacteria] drivers of sediment ETS activity. ETS activity was notably higher in the eutrophic Lake Nueva (34.91 microl O(2) g(-1) D.W. h(-1)) than in the hypertrophic Lake Honda (24.99 microl O(2) g(-1) D.W. h(-1)). Strong spatial differences were observed in ETS in both study sites. Highest ETS values were achieved at the surface sediment at the deepest sampling station in each lake and a notable reduction in ETS with sediment depth was observed. By using linear regression and multiple regression analysis, OM was identified as the best predictor of ETS in Lake Honda while Chl a was the best predictor in Lake Nueva. The strong influence of OM supply on ETS activity in sediment from Lake Honda was the consequence of the labile nature of sedimentary OM, while a more refractory OM (with a higher contribution of vascular plants) comprised most of the sedimentary OM from Lake Nueva. By contrast, a large contribution of phytobenthos (supported by a higher lake water transparency) to ETS has been recognized in sediments from Lake Nueva. In summary, the results of this study revealed that the relative importance of planktonic primary producers (phytoplankton), benthic algae and vascular plants in the study sites could explain the differences observed in the intensity of sediment ETS as well as in their drivers.

  3. Scale and Seasonal Controls on Nitrate and Sediment Retention in Freshwater Tidal Wetlands

    Science.gov (United States)

    Prestegaard, K. L.; Seldomridge, E.; Statkiewicz, A.

    2013-12-01

    Channel networks in freshwater tidal wetlands convey water, sediment, and solutes into marsh interiors where sediment deposition and biogeochemical processes, such as denitrification and nitrogen uptake occur. Tidal inlets that connect these channel network systems to the main estuary define the initial solute or sediment load into these systems, but channel, soil, and vegetation characteristics influence nitrate and sediment retention. We used field measurements and remotely sensed images to determine marsh area, stream length, inlet morphology, and channel morphology for the 267 marshes in the freshwater tidal ecosystem. Discharge and water volume over high tidal cycles was measured at selected inlets representative of the range of inlet sizes in the ecosystem. Aquatic vegetation distribution and density was also measured at these inlets. These data were used to develop geomorphic-hydraulic relationships for the marshes for winter (no vegetation) and summer (vegetated) conditions. Nitrate and sediment retention were determined from field mass balance measurements based on water flux and concentration measurements taken over tidal cycle at inlets to selected marshes of varying size over a 3-year period. These mass balance data indicate that net nitrate retention is a simple function of tidal water volume for marshes of different sizes and for various vegetated conditions. These data suggest that nitrate retention is transport limited for the range of initial nitrate concentrations observed in this system. Although nitrate retention was a function of tidal water volume, it was also seasonally variable due to restrictions in water flow and volume caused by aquatic vegetation in summer months. Sediment retention is seasonally variable due to the strong controls exerted by emergent and submerged aquatic vegetation and decoupled from the water volume dependence observed for nitrate retention. Variations in sediment retention caused by vegetation resulted in channel

  4. Mercury Methylation, Demethylation, and Bioavailability in the Hyporheic Sediments of a Northern Wisconsin Wetland

    Science.gov (United States)

    Creswell, J. E.; Babiarz, C. L.; Shafer, M. M.; Roden, E. E.; Armstrong, D. E.

    2007-12-01

    It is generally accepted that wetland sediments have a high potential to produce methylmercury, yet the factors controlling the relevant chemical transformations are poorly understood. Previous studies suggest that sulfate- reducing bacteria play an important role in methylation, but iron-reducing bacteria may also participate in this process. Methylation rates are influenced by both the concentration of Hg(II) and its speciation, which affects its bioavailability. Net accumulation depends also on demethylation rates, rates which may be significant in these systems. The objective of this study is to gain a better understanding of the main factors controlling the bioavailability of inorganic mercury for the production of methylmercury in wetland hyporheic zones. Stable isotopes of mercury are being used to investigate potential methylation and demethylation rates in the hyporheic sediments of Allequash Creek, near Boulder Junction, WI. Other techniques that are being applied to examine the chemical and biological drivers of mercury methylation and bioavailability include tin-reducible mercury "titrations" to measure the concentration of strong mercury-binding ligands in porewater, 14C-acetate uptake assays to determine the activity of the native microbial consortia , ion exchange resin experiments to explore the role of dissolved organic carbon in mercury binding, and inhibition studies (e.g. molybdenum amendments) of sulfate-reducing bacteria to assess their role in producing methylmercury. Manipulations of environmental conditions in laboratory microcosms are used to determine the relative importance of physical factors, such as temperature, and biogeochemical factors, such as sulfate, sulfide, dissolved organic carbon (DOC), and iron levels, on the fate of mercury in hyporheic systems. Preliminary results show that while significant levels of inorganic mercury are present in the hyporheic groundwater, strong mercury-binding ligands in the wetland porewaters at a

  5. [Distribution and potential ecological risk assessment of heavy metals in sediments of Zhalong Wetland].

    Science.gov (United States)

    Ye, Hua-Xiang; Zang, Shu-Ying; Zhang, Li-Juan; Zhang, Yu-Hong

    2013-04-01

    This study investigated the concentrations of heavy metals in the sediments of the Zhalong Wetland using ICP-MS, analyzed their spatial distributions, evaluated the potential ecological risk, and explored the pollution sources and environmental influencing factors. The results can be summarized as the followings: (1) The concentrations of Hg, Cd, As, Cu, Pb, Zn and Cr were 0.065, 0.155, 10.26, 18.20, 21.35, 52.08 and 46.47 mg x kg(-1), respectively, which were all above the soil background values of the Songnen Plain. Their spatial distributions were distinctly different. The concentration of heavy metals in the north was higher than that in the south, and the east was higher than the west. Particularly in the eastern region, the concentrations of Hg and Cd were 20.8 and 32.4 times the minimum values of the whole area. And in the core zone, the concentration was relatively low. (2) The sequence of the potential ecological risk posed by the metals was Hg > Cd > As > Pb > Cu > Cr > Zn. The average potential ecological risk index (RI) of the Zhalong Wetland was 171.9 (ranged from 76.9-473.5), suggesting a moderate ecological risk. However, the potential ecological risk was extremely high in the east which should be treated as the major heavy metal pollution prevention site in the future. (3) Except for Hg and Pb, the concentrations of all heavy metals were significantly correlated to each other, indicating that those heavy metals had homology. (4) Organic matter was the major environmental influencing factor. However, the trend of land salinization in the Zhalong Wetland has been intensified, indicating a higher risk of heavy metal releasing from the sediments, to which the local authorities should pay enough attention.

  6. Biogeochemical gradients and microbial communities in Winogradsky columns established with polluted wetland sediments.

    Science.gov (United States)

    Babcsányi, Izabella; Meite, Fatima; Imfeld, Gwenaël

    2017-08-01

    A Winogradsky column is a miniature ecosystem established with enriched sediments that can be used to study the relationship between biogeochemical gradients, microbial diversity and pollutant transformation. Biogeochemical processes and microbial communities changed with time and depth in Winogradsky columns incubated with heavy-metal-polluted wetland sediments for 520 days. 16S rRNA surveys were complemented by geochemical analyses, including heavy metal proportioning, to evaluate gradients in the mostly anoxic columns. Oxygen was depleted below the water-sediment interface (WSI), while NH4+, Fe2+, S2- and acetate increased by one order of magnitude at the bottom. Microbial niche differentiation occurred mainly by depth and from the light-exposed surface to the interior of the columns. Chemical gradients resulting from nutrient uptake by algae, and from iron and sulphate reduction mainly drove diversification. Heavy-metal proportioning did not significantly influence microbial diversity as Cu and Zn were immobilised at all depths. Proteobacteria were abundant in the top water and the WSI layers, whereas Firmicutes and Bacteroida dominated down-core. Together with low diversity and richness of communities at the WSI and column bottom, changes in the bacterial community coincided with algal-derived carbon sources and cellulose fermentation, respectively. We expect this study to be the starting point for the use Winogradsky columns to study microbial and geochemical dynamics in polluted sediments. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  7. Trace metals in sediments and benthic animals from aquaculture ponds near a mangrove wetland in Southern China.

    Science.gov (United States)

    Wu, Hao; Liu, Jinling; Bi, Xiangyang; Lin, Guanghui; Feng, Christopher C; Li, Zhengjie; Qi, Fei; Zheng, Tianling; Xie, Liqi

    2017-04-15

    In this study, we measured the concentrations of trace metals (Cr, Cu, Zn, As, Cd, Pb and Hg) in typical cultured animals (crabs, clams, and shrimps) and sediments from aquaculture ponds nearby mangrove wetlands in Zhangjiang estuary, China. The contents of Cr, Cu, Cd, and Pb in mangrove sediments were significantly higher than those in pond sediments, while an inverse distribution was observed for Zn, As, and Hg. Significantly higher concentrations of trace metals were found in clams from the mangrove mudflats compared to those from the aquaculture ponds. The sources of trace metals in the clams were primarily from organic fertilizer, whereas those in the shrimp were from contaminated sediment. The results of geo-accumulation index and the ecological risk assessment indicated that the aquaculture ponds near the mangrove wetlands in this subtropical estuary posed a special risk of endogenous and exogenous trace metal pollution to nearby systems. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Impact of sulfate pollution on anaerobic biogeochemical cycles in a wetland sediment.

    Science.gov (United States)

    Baldwin, Darren S; Mitchell, Alison

    2012-03-15

    The impact of sulfate pollution is increasingly being seen as an issue in the management of inland aquatic ecosystems. In this study we use sediment slurry experiments to explore the addition of sulfate, with or without added carbon, on the anaerobic biogeochemical cycles in a wetland sediment that previously had not been exposed to high levels of sulfate. Specifically we looked at the cycling of S (sulfate, dissolved and particulate sulfide--the latter measured as acid volatile sulfide; AVS), C (carbon dioxide, bicarbonate, methane and the short chain volatile fatty acids formate, acetate, butyrate and propionate), N (dinitrogen, ammonium, nitrate and nitrite) and redox active metals (Fe(II) and Mn(II)). Sulfate had the largest effects on the cycling of S and C. All the added S at lower loadings were converted to AVS over the course of the experiment (30 days). At the highest loading (8 mmol) less than 50% of consumed S was converted to AVS, however this is believed to be a kinetic effect. Although sulfate reduction was occurring in sediments with added sulfate, dissolved sulfide concentrations remained low throughout the study. Sulfate addition affected methanogenesis. In the absence of added carbon, addition of sulfate, even at a loading of 1 mmol, resulted in a halving of methane formation. The initial rate of formation of methane was not affected by sulfate if additional carbon was added to the sediment. However, there was evidence for anaerobic methane oxidation in those sediments with added sulfate and carbon, but not in those sediments treated only with carbon. Surprisingly, sulfate addition had little apparent impact on N dynamics; previous studies have shown that sulfide can inhibit denitrification and stimulate dissimilatory nitrate reduction to ammonia. We propose that because most of the reduced sulfur was in particulate form, levels of dissolved sulfide were too low to interfere with the N cycle.

  9. The Influence of Coastal Wetland Zonation on Surface Sediment and Porewater Mercury Speciation

    Science.gov (United States)

    Marvin-DiPasquale, M. C.; Windham-Myers, L.; Wilson, A. M.; Buck, T.; Smith, E.

    2014-12-01

    An investigation of mercury (Hg) speciation in saltmarsh surface sediment (top 0-2 cm) and porewater (integrated 0-50 cm) was conducted along two monitoring well transects established within North Inlet Estuary (S. Carolina, USA) as part of the NOAA sponsored National Estuarine Research Reserve (NERR) network. Transects were perpendicular to the shoreline, from the forested uplands to the edge of the tidal channel, and traversed a range of vegetated zones from the high marsh (pickleweed, rush, and salt panne-dominated) to the low marsh (cordgrass dominated), as mediated by elevation and tidal inundation. Sediment grain size and organic content explained 95% of the variability in the distribution of total Hg (THg) in surface sediment. Tin-reducible 'reactive' mercury (HgR) concentration was 10X greater in the high marsh, compared to the low marsh, and increased sharply with decreasing sediment pH values below pH=6. The percentage of THg as HgR decreased as sediment redox conditions became more reducing. There were no significant differences in surface sediment methylmercury (MeHg) concentrations between high and low marsh zones. In contrast, porewater MeHg concentrations were 5X greater in the high marsh compared to the low marsh. As a percentage of THg, mean porewater %MeHg was 23% in the low marsh and 51% in the high marsh, reaching levels of 73-89% in a number of high marsh sites. Calculations of partitioning between porewater and the solid phase suggest stronger binding to particles in the low marsh and a shift towards the dissolved phase in the high marsh for both THg and MeHg. These results are consistent with a conceptual model for coastal wetlands where the less frequently inundated high marsh zone may be important in terms of MeHg production and enhanced subsurface mobilization, partially due to the subsurface mixing of saline estuarine water and freshwater draining in from the uplands area.

  10. Assessment of priority phenolic compounds in sediments from an extremely polluted coastal wetland (Lake Maryut, Egypt).

    Science.gov (United States)

    Khairy, Mohammed A

    2013-01-01

    Although high concentrations of trace organic pollutants were recorded along the Egyptian Mediterranean Coast and its corresponding coastal wetlands, no published data are available for the levels of phenolic compounds. Thus, this work aimed to investigate the levels of phenolic compounds in sediments of a heavily polluted coastal wetland (Lake Maryut, Egypt). For that purpose, a method was optimized for the extraction and detection of chlorophenols, methylphenols, and nitrophenols in sediments using GC-MS. Sediments were extracted with 0.1 M NaOH/methanol by sonication. Cleanup of sediment extracts using liquid-liquid extraction and SPE was found important to remove most of the interfering co-extracts. The proposed analytical methodology was validated by analysis of matrix spikes. Detection limits were 0.063-0.694 μg/kg dw for sediments. Good recoveries (70-110%) and precision values (RSD Lake Maryut. Results revealed that higher concentrations were observed in the main basin (MB) of Lake Maryut affected by the discharge of effluents from a primary wastewater treatment plant, direct discharge of industrial effluents, domestic wastes, and agricultural effluents from Qalaa Drain (QD). Chlorophenols (CPs) were the major group detected in the lake sediments followed by methylphenols (MPs) and nitrophenols (NPs). CPs were dominated by 2-, 4-, and 3-chlorophenols. Concentrations of CPs were higher at the north and northwestern parts of the MB indicating the influence of industrial effluents discharged into the lake. On the other hand, higher concentrations of NPs were observed at the south and southwestern parts of the MB, which is subjected to the discharge of agricultural and domestic effluents via QD. Results of the risk assessment revealed that phenol, cresols, 2,4-dinitrophenol, 4-NP, 2-CP, 2,3,4,6-tetrachlorophenol and 2,4-dimethylphenol are contaminants of concern and that adverse ecological effects could possibly occur to benthic species from the exposure to

  11. Effectiveness of vegetation buffers surrounding playa wetlands at contaminant and sediment amelioration

    Science.gov (United States)

    Haukos, David A.; Johnson, Lacrecia A.; Smith, Loren M.; McMurry, Scott T.

    2016-01-01

    Playa wetlands, the dominant hydrological feature of the semi-arid U.S. High Plains providing critical ecosystem services, are being lost and degraded due to anthropogenic alterations of the short-grass prairie landscape. The primary process contributing to the loss of playas is filling of the wetland through accumulation of soil eroded and transported by precipitation from surrounding cultivated watersheds. We evaluated effectiveness of vegetative buffers surrounding playas in removing metals, nutrients, and dissolved/suspended sediments from precipitation runoff. Storm water runoff was collected at 10-m intervals in three buffer types (native grass, fallow cropland, and Conservation Reserve Program). Buffer type differed in plant composition, but not in maximum percent removal of contaminants. Within the initial 60 m from a cultivated field, vegetation buffers of all types removed >50% of all measured contaminants, including 83% of total suspended solids (TSS) and 58% of total dissolved solids (TDS). Buffers removed an average of 70% of P and 78% of N to reduce nutrients entering the playa. Mean maximum percent removal for metals ranged from 56% of Na to 87% of Cr. Maximum removal was typically at 50 m of buffer width. Measures of TSS were correlated with all measures of metals and nutrients except for N, which was correlated with TDS. Any buffer type with >80% vegetation cover and 30–60 m in width would maximize contaminant removal from precipitation runoff while ensuring that playas would continue to function hydrologically to provide ecosystem services. Watershed management to minimize erosion and creations of vegetation buffers could be economical and effective conservation tools for playa wetlands.

  12. Surficial geology and distribution of post-impoundment sediment of the western part of Lake Mead based on a sidescan sonar and high-resolution seismic-reflection survey

    Science.gov (United States)

    Twichell, David C.; Cross, VeeAnn A.; Rudin, Mark J.; Parolski, Kenneth F.

    1999-01-01

    Sidescan sonar imagery and high-resolution seismic-reflection profiles were collected in Las Vegas Bay and Boulder Basin of Lake Mead to determine the surficial geology as well as the distribution and thickness of sediment that has accumulated in these areas of the lake since the completion of Hoover Dam in 1935 (Gould, 1951). Results indicate that the accumulation of post-impoundment sediment is restricted to the original Colorado River bed which runs down the axis of Boulder Basin from Boulder Canyon to Hoover Dam, and the old Las Vegas Creek bed that bisects Las Vegas Bay. The sediment cover along the original Colorado River bed is continuous and is typically greater than 10-m thick throughout much of its length with the thickness in some areas exceeding 35 meters. The flat-lying nature of the deposits suggests that they are the result of turbidity currents that flow the length of the lake. The sediment cover in Las Vegas Bay is much thinner (rarely exceeding 2 m in thickness) and more discontinuous. The source for these sediments presumably is Las Vegas Wash and a series of other ephemeral washes that empty into this part of the lake. The presence of sediments along the entire length of the Las Vegas Creek bed suggests that turbidity currents probably are active here as well, and that sediment has been transported from these streams at least 10 km down the axis of this valley to where it enters Boulder Basin. Alluvial deposits and rock outcrops are still exposed on large parts of the lake floor.

  13. Historical variation of heavy metals with respect to different chemical forms in recent sediments from Xianghai Wetlands, Northeast China

    Energy Technology Data Exchange (ETDEWEB)

    Wang, G.P.; Liu, J.S.; Tang, J. [Chinese Academy of Science, Changchun (China)

    2004-09-15

    The research aimed to determine whether pollution trends could be reconstructed from sediment records at the downstream wetlands of the Huolin River. Sediment cores, representing a range of watershed characteristics and anthropogenic impacts, were collected from two marshes at the Xianghai Wetlands in order to trace the historical variation of heavy metals, accumulation rates, and chemical forms. Cores were Pb-210- and Cs-137-dated, and these data were used to calculate sedimentation rates and sediment accumulation rates that were compared with environmental change. Ranges of dry mass accumulation rates and sedimentation rates were0.27-0.96 g/cm{sup 2}/yr and 0.27-0.90 cm/yr. After normalization to Al the anthropogenic enrichment of Cu, Zn, Cr, and Pb occurred in the upper layer of sediments and indicated that heavy metal contamination from the hydrologic inputs primarily occurred after the 1980s, a result consistent with two decades of surface coal-mining history within the upstream region of Huolin River. Sediment inputs of most heavy metals at Xianghai Wetlands began to increase around 1885 and were generally consistent with the time of the Qing Dynasty's immigration settlement. The anthropogenic inputs of Cu, Zn, Fe, Mn, Cr, and Pb have been 1.20-3.67 times greater than their natural inputs after the 1980s, which may be due to increased inputof heavy metal-rich alluvial deposits derived from surface coal-mining activities in the watershed. Sequential extraction showed that heavy metals in sediment cores were associated with the lithogenic bonding forms and least with the exchangeable fraction (except Pb). The major fraction of Pb was in the Fe-Mn oxide fraction, indicating that Pb in these sediments had greater mobility and that it might befrom anthropogenic sources.

  14. Effects of flow modification on a cattail wetland at the mouth of Irondequoit Creek near Rochester, New York: Water levels, wetland biota, sediment, and water quality

    Science.gov (United States)

    Coon, William F.

    2004-01-01

    An 11-year (1990-2001) study of the Ellison Park wetland, a 423-acre, predominantly cattail (Typha glauca) wetland at the mouth of Irondequoit Creek, was conducted to document the effects that flow modifications, including installation of a flow-control structure (FCS) in 1997 and increased diversion of stormflows to the backwater areas of the wetland, would have on the wetland's ability to decrease chemical loads transported by Irondequoit Creek into Irondequoit Bay on Lake Ontario. The FCS was designed to raise the water-surface elevation and thereby increase the dispersal and detention of stormflows in the upstream half of the wetland; this was expected to promote sedimentation and microbial utilization of nutrients, and thereby decrease the loads of certain constituents, primarily phosphorus, that would otherwise be carried into Irondequoit Bay. An ecological monitoring program was established to document changes in the wetland's water levels, biota, sedimentation rates, and chemical quality of water and sediment that might be attributable to the flow modifications.Water-level increases during storms were mostly confined to the wetland area, within about 5,000 ft upstream from the FCS. Backwater at a point of local concern, about 13,000 ft upstream, was due to local debris jams or constriction of flow by bridges and was not attributable to the FCS.Plant surveys documented species richness, concentrations of nutrients and metals in cattail tissues, and cattail productivity. Results indicated that observed differences among survey periods and between the areas upstream and downstream from the FCS were due to seasonal changes in water levels—either during the current year or at the end of the previous year's growing season—that reflected the water-surface elevation of Lake Ontario, rather than water-level control by the FCS. Results showed no adverse effects from the naturally high water levels that prevail annually during the spring and summer in the wetland

  15. Investigation on concentration of elements in wetland sediments and aquatic plants

    Directory of Open Access Journals (Sweden)

    H. Janadeleh

    2016-01-01

    Full Text Available The major aim of the present study was to investigate element (Fe, Ni, Pb, V, Zn concentrations in sediment and different tissues of Phragmities australis and Typha latifolia in Hor al-Azim Wetland Southwest Iran. Sampling of sediments and aquatic plants was carried out during spring and summer 2014. Results showed that the mean  concentrations of elements in Phragmities australis  in root and stem-leaf were as follows: Iron:4448 mg/kg, Nickel: 28 mg/kg, Lead:8 mg/kg, Vanadium:10 mg/kg  and Zinc 15.5 mg/kg in root and: Fe:645 mg/kg, Ni:15 mg/kg, Pb:4 mg/kg, V:4 mg/kg and Zinc 16 mg/kg respectively. Also, the mean concentrations of Fe, Ni, Pb, V and Zn in roots of Typha latifolia were 8696 mg/kg, 34 mg/kg, 5 mg/kg, 19 mg/kg and 27 mg/kg respectively. The mean concentrations of Fe, Ni, V, Pb, Zn in stem-leaves of Typha latifolia were as follows: 321 mg/kg, 3 mg/kg, 7 mg/kg, 2 mg/kg and 14 mg/kg respectively. The mean concentrations of Fe, Ni, V, Pb and zinc were as: 40991 mg/kg, 65 mg/kg, 60 mg/kg, 31 mg/kg, 60 mg/kg respectively in surface sediment of study area. Concentration pattern of elements in sediment were as: Fe>Ni>Zn>V>Pb. The highest concentration of elements in the plant was seen in the roots. Also, Typha latifolia can uptake more concentration of elements than Phragmities australis. Based on the enrichment factor, Ni in summer had the highest EF values among the elements studied and it has a moderate enrichment.

  16. Subdivision of Pantanal Quaternary Wetlands: Modis Ndvi Timeseries in the Indirect Detection of Sediments Granulometry

    Science.gov (United States)

    Penatti, N. C.; de Almeida, T. I. R.

    2012-07-01

    The Pantanal is the world's largest wetland presenting a variety of ecological sub-regions. The region is characterized by seasonal floods followed by long droughts. At this period, some areas rapidly dry, while others remain soaked. The study hypothesis was based on the statement that this phenomenon cannot be totally explained by small relief variations but by the sediment granulometry: the pelitic sediments allow the soil to retain moisture longer, implying that the vegetation has greater possibilities of continuing photosynthetically active even during the drought. It was developed based on the spectral behaviour of MODIS products, validated by previous fieldwork. Using MODIS, we studied a large scale patterns in spatial and seasonal dynamics of the vegetation in different regions of Pantanal. So, two indirect parameters of the local physical environment - sediment granulometry and water availability - potentially can be estimated. We calculated the NDVI from MOD09GQ for rainy and dry seasons, generating triplets (NDVI/NIR and Red bands) that allowed to identify vegetation changes in those periods. The 16-days composites of NDVI (MOD13Q1) were used to generate a 5-year time-series for pixels associated with 161 locals sampled for granulometric analyses. The samples were taken in 10 different areas from the 20 geological and environmentally homologous areas delimited in this research. The clear tendency in the time-series confirms the working hypothesis, indicating that there is a high relationship between drought-related changes in vegetation extracted from NDVI and sediment texture, parameter that plays an important role in soil moisture, influencing the vegetation response to droughts.

  17. The mismatch of bioaccumulated trace metals (Cu, Pb and Zn) in field and transplanted oysters (Saccostrea glomerata) to ambient surficial sediments and suspended particulate matter in a highly urbanised estuary (Sydney estuary, Australia).

    Science.gov (United States)

    Lee, Jung-Ho; Birch, Gavin F

    2016-04-01

    A significant correlation between sedimentary metals, particularly the 'bio-available' fraction, and bioaccumulated metal concentrations in the native Sydney rock oyster (Saccostrea glomerata) tissues has been successfully demonstrated previously for Cu and Zn in a number of estuaries in New South Wales, Australia. However, this relationship has been difficult to establish in a highly modified estuary (Sydney estuary, Australia) where metal contamination is of greatest concern and where a significant relationship would be most useful for environmental monitoring. The use of the Sydney rock oyster as a biomonitoring tool for metal contamination was assessed in the present study by investigating relationships between metals attached to sediments and suspended particulate matter (SPM) to bioaccumulated concentrations in oyster tissues. Surficial sediments (both total and fine-fraction), SPM and wild oysters were collected over 3 years from three embayments (Chowder Bay, Mosman Bay and Iron Cove) with each embayment representing a different physiographic region of Sydney estuary. In addition, a transplant experiment of farmed oysters was conducted in the same embayments for 3 months. No relationship was observed between sediments or SPM metals (Cu, Pb and Zn) to tissue of wild oysters; however, significant relationship was observed against transplanted oysters. The mismatch between wild and farmed, transplanted oysters is perplexing and indicates that wild oysters are unsuitable to be used as a biomonitoring tool due to the involvement of unknown complex factors while transplanted oysters hold strong potential.

  18. Distribution and ecological risk assessment of heavy metals in surface sediments of a typical restored mangrove-aquaculture wetland in Shenzhen, China.

    Science.gov (United States)

    Feng, Jianxiang; Zhu, Xiaoshan; Wu, Hao; Ning, Cunxin; Lin, Guanghui

    2017-01-07

    The restoration of wetlands has attracted the attention in different countries. Restored coastal wetlands, especially urban wetlands, are sensitive to external pressures. Thus, it is necessary to evaluate the efficiency of the restoration of coastal wetlands, which benefits their management and functional maintenance. In this study, a restored mangrove-aquaculture system in Waterlands Resort at Shenzhen was selected for analysis. The distribution and ecological risk assessment of heavy metals in surface sediments were investigated. The results showed that restoration could effectively decrease the heavy metal concentrations in the sediment, while the restored mangrove posed a moderate ecological risk. Most of the heavy metal concentrations were higher during the dry season compared with the wet season. In addition, during the whole investigation, the sediment quality remained failed to achieve the marine sediment criteria required for aquaculture in China.

  19. Distribution and sources of polycyclic aromatic hydrocarbons in the sediment of a sub-tropical coastal wetland.

    Science.gov (United States)

    Zheng, Gene J; Man, Ben K W; Lam, James C W; Lam, Michael H W; Lam, Paul K S

    2002-03-01

    Sediment cores (0-35cm below surface) from twelve sampling stations in the Mai Po and Inner Deep Bay Ramsar Site of Hong Kong were retrieved in the period March-December 1999. Vertical profiles of 15 priority polycyclic aromatic hydrocarbons (PAHs) in each sediment core were determined. Ranges of total PAH concentration, [sigmaPAH], in the wetland sediment were 0.18-0.83 (N = 0.36) microg/g dried sediment (mudflats) and 0.63-0.96 (x = 0.77) microg/g dried sediment (mangroves). A decreasing trend in depth averaged [sigmaPAH] was observed from the landward end towards the seaward end of the Marshes. On the mudflats, vertical profiles of the PAHs were quite uniform. At the fringe of the Mai Po mangroves, significantly higher concentration of all PAHs was observed at the upper 0 to -8 cm layer. No significant difference in the distribution patterns of the 15 priority PAHs in summer and winter was observed. This indicates that distribution of PAHs in the sediment of the Mai Po Marshes is not very sensitive to sub-tropical climatic changes of the region. Two PAH isomer ratios, [Phen]/([Phen] + [Anthra]) and [Pyrene]/([Pyrene] + [Fluoran]), were used to identify potential sources of PAH contamination in the wetland. Results revealed that local deposition is a more important source than long-range atmospheric transportation.

  20. Reactive and unreactive iron minerals hosting arsenic within seasonal wetland sediments of the Mekong Delta

    Science.gov (United States)

    Stuckey, J.; Schaefer, M.; Lezama, J.; Dittmar, J.; Fendorf, S.

    2013-12-01

    Millions of people in the deltaic regions of S/SE Asia regularly consume arsenic contaminated groundwater. Within the Mekong Delta of Cambodia, for example, arsenic persists within the groundwater despite being flushed by several pore volumes of recharge. The identity and reactivity of the minerals contributing to the persistence of arsenic in the deltaic aquifers remain elusive. Here we seek to define the molecular form of the arsenic and its host phases along defined flow paths in seasonally saturated wetlands: i) a grassland flooded for ~ 3 - 4 months of the year (Grassland) and ii) an abandoned river channel saturated for ~ 5 - 6 months (Oxbow). Sediment cores were retrieved by pounding aluminum cores into a fresh profile exposed by successive excavation. The cores were sealed with melted wax in the field and stored at 4 °C until processed. Depths of 0.2 to 6 m were sampled at the Grassland site and 0.2 to 4 m at the Oxbow site. Sediments were dried under 95%N2/5%H2 atmosphere. A 1 M HCl extraction dissolving the 'reactive' iron (predominantly poorly crystalline iron oxides) solubilized 3 - 7 % of the total iron in the Grassland site and 8 - 41 % in the Oxbow site. A citrate-bicarbonate-dithionite (CBD) extraction was performed to extract reducible iron (predominantly iron oxides), accounting for 35 - 50 % of the total iron in the Grassland site and 27 - 44 % in the Oxbow site. Correspondingly, least squares fitting of k3 - weighted chi(k) iron extended X-ray absorption fine structure (EXAFS) spectra showed that goethite and hematite together comprised 34 - 50 % of the iron mineralogy in the mineral sediments of the Grassland site and 24 - 38 % of those in the Oxbow site. The remaining iron minerals present were predominantly silicates. Iron EXAFS spectra were obtained for the post-CBD extracted sediments, theoretically containing only non-reducible iron. Least squares fitting of the bulk (pre-CBD extracted) sediments was performed a second time with the

  1. Anaerobic ammonium oxidation in sediments of surface flow constructed wetlands treating swine wastewater.

    Science.gov (United States)

    Chen, Liang; Liu, Feng; Jia, Fen; Hu, Ya-Jun; Lai, Cui; Li, Xi; Luo, Pei; Xiao, Run-Lin; Li, Yong; Wu, Jin-Shui

    2017-02-01

    Anaerobic ammonium oxidation (anammox) was suggested to be involved in the nitrogen (N) removal process in constructed wetlands (CWs). Nevertheless, its occurrence and role in CWs treating swine wastewater have not been well evaluated yet. In this study, we investigated the diversity, activity, and role of anammox bacteria in sediments of mesoscale surface flow CWs (SFCWs) subjected to different N loads of swine wastewater. We found that anammox bacteria were abundant in SFCW sediments, as indicated by 7.5 × 10(5) to 3.5 × 10(6) copies of the marker hzsB gene per gram of dry soil. Based on stable isotope tracing, potential anammox rates ranged from 1.03 to 12.5 nmol N g(-1) dry soil h(-1), accounting for 8.63-57.1% of total N2 production. We estimated that a total N removal rate of 0.83-2.68 kg N year(-1) was linked to the anammox process, representing ca. 10% of the N load. Phylogenetic analyses of 16S ribosomal RNA (rRNA) revealed the presence of multiple co-occurring anammox genera, including "Candidatus Brocadia" as the most common one, "Ca. Kuenenia," "Ca. Scalindua," and four novel unidentified clusters. Correlation analyses suggested that the activity and abundance of anammox bacteria were strongly related to sediments pH, NH4(+)-N, and NO2(-)-N. In conclusion, our results confirmed the presence of diverse anammox bacteria and indicated that the anammox process could serve as a promising N removal pathway in the treatment of swine wastewater by SFCWs.

  2. Pollution characteristics and ecological risk assessment of HCHs and DDTs in estuary wetland sediments from the Bohai Bay, North China.

    Science.gov (United States)

    Liu, Qing; Tian, Shengyan; Jia, Rui; Liu, Xianbin

    2015-12-09

    Hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs) tend to persist in the environment for long periods of time. The concentration and distribution of HCHs and DDTs were investigated in surface sediments of Yongdingxinhe wetland and Binhai wetland by gas chromatography-mass spectrometer (GC-MS). All isomers of HCHs and DDTs were detected in all of the samples. The concentrations of total HCHs (ΣHCHs) in two wetland sediments ranged from 69.81 to 379.28 ng · g (-1), with a mean value of 224.55 ng · g (-1). The concentrations of total DDTs (ΣDDTs) ranged from 98.32 to 129.10 ng · g (-1), with a mean value of 113.71 ng · g (-1). The results of an ecological risk assessment demonstrated that there was high-risk ecological effect of organochlorine pesticides (OCPs) on the estuary wetlands. Lindane and technical DDTs were found to be the main sources of OCPs.

  3. Geochemical and isotopic signatures of surficial sediments from the western continental shelf of India: Inferring provenance, weathering, and the nature of organic matter

    Digital Repository Service at National Institute of Oceanography (India)

    Kurian, S.; Nath, B.N.; Kumar, N.C.; Nair, K.K.C.

    matter. Major elements such as Si, Ti, Mg, and discrimination plots involving alkalies and silica have shown a distinct north-south provinciality, with the source signatures pointing at Deccan basalt for sediments in the north (from Dwaraka to Goa...

  4. Geochemical investigation of Sasa tailings dam material and its influence on the Lake Kalimanci surficial sediments (Republic of Macedonia – preliminary study

    Directory of Open Access Journals (Sweden)

    Petra Vrhovnik

    2011-12-01

    Full Text Available This research is aimed at investigating the mineralogical characteristics of the tailings material and heavy metal contents of the tailings material deposited close to the Sasa Pb-Zn Mine in the Osogovo Mountains (eastern Macedonia and on its possible impact on Lake Kalimanci. The mineral composition of Sasa Mine tailings materialis dominated by quartz, pyrite, galena, sphalerite, magnetite and others. Geochemical analysis was performed in a certified commercial laboratory for the following elements: Mo, Cu, Pb, Zn, Ni, As, Cd, Sb, Bi, Ag, Al, Fe, Mn, S.Analysis revealed very high concentrations of toxic metals in the tailing material – with average values [ mg kg-1]:Mo 2.9, Cu 279, Pb 3975, Zn 5320, Ni 30, As 69, Cd 84, Sb 4.2, Bi 9.4 and Ag 4.1. The multi-element contamination of Sasa Mine tailings material was assigned a pollution index greater of 15, indicating that the tailings material from Sasa Mine contains very high amounts of toxic metals and represents a high environmental risk for surrounding ecosystems. For this reason the influence of discharged tailings dam material into Lake Kalimanci which liesapproximately 12 km lower than Sasa Mine, was also established. Calculated pollution index values for Lake Kalimancisediments vary from 21 to 65 and for Sasa mine surficial tailings dam material from 15 to 60.

  5. Late Pleistocene/Holocene wetland events recorded in southeast Tengger Desert lake sediments, NW China

    Institute of Scientific and Technical Information of China (English)

    D. B. Madsen; CHEN Fahu; Ch. G. Oviatt; ZHU Yan; P. J. Brantingham; R. G. Elston; R. L. Bettinger

    2003-01-01

    The area along the eastern and southeastern margins of the Tengger Desert, NW China, which is sensitive to the summer monsoon variations, was selectedfor studying the environmental conditions surrounding the transition between Paleolithic foragers and Neolithic farmer/pastoral- ists. Short cores were obtained from four lake basins in the southwestern Tengger using a hand-driven piston coring device. Proxies from these cores were supplemented by ra- diocarbon ages obtained from lake sediment cores, shoreline features and spring mound deposits. Together these records provide evidence of millennial-scale climate change events from the Pleistocene-Holocene transition to the present. Lake/wetland events, representing periods of more intensive summer monsoon, occur in the records at ~12.7-11.6, ~10.1, ~9.3, ~8.0, ~5.4, ~1.5, and ~0.8 ka BP. They do suggest that century- to millennial-scale climatic cycles are characteristic of the Holocene in the southeastern Tengger Desert although the chronology must be considered extremely tentative.

  6. Sedimentology, geochemistry, pollution status and ecological risk assessment of some heavy metals in surficial sediments of an Egyptian lagoon connecting to the Mediterranean Sea.

    Science.gov (United States)

    El-Said, Ghada F; Draz, Suzanne E O; El-Sadaawy, Manal M; Moneer, Abeer A

    2014-01-01

    Spatial distribution of heavy metals (Co, Cu, Ni, Cr, Mn, Zn and Fe) was studied on Lake Edku's surface sediments in relation to sedimentology and geochemistry characteristics and their contamination status on the ecological system. Lake Edku's sediments were dominated by sandy silt and silty sand textures and were enriched with carbonate content (9.83-58.46%). Iron and manganese were the most abundant heavy metals with ranges of 1.69 to 8.06 mg g(-1) and 0.88 to 3.27 mg g(-1), respectively. Cobalt and nickel showed a harmonic distribution along the studied sediments. The results were interpreted by the statistical means. The heavy metal pollution status and their ecological risk in Lake Edku was evaluated using the sediment quality guidelines and the contamination assessment methods (geoaccumulation, pollution load and potential ecological risk indices, enrichment factor, contamination degree as well as effect range median (ERM) and probable effect level (PEL) quotients). Amongst the determined heavy metals, zinc had the most ecological risk. Overall, the heavy metals in surface sediments showed ecological effect range from moderate to considerable risk, specially, in the stations in front of the seawater and in drain sources that had the highest toxic priority.

  7. Dynamics of arsenic in salt marsh sediments from Dongtan wetland of the Yangtze River estuary,China

    Institute of Scientific and Technical Information of China (English)

    Yongjie Wang; Limin Zhou; Xiangmin Zheng; Peng Qian; Yonghong Wu

    2012-01-01

    The mobility and transformation of arsenic (As) in salt marsh sediments were investigated in Dongtan wetland of the Yangtze River estuary,China.As in surface water,pore water and the rhizosphere sediments were quantified.The microcosm incubation experiments were conducted during the flooding of the sediments to examine As dynamics that occurred during changing redox conditions.The concentrations of dissolved As in pore water (0.04-0.95 μmol/L) were significantly greater than that in surface water (0.03-0.06μmol/L).Under anoxic conditions,the reactive As could be initially mobilized by the reductive dissolution of Fe(Ⅲ) (hydr)oxides.Subsequently,most of the dissolved As was likely to be associated with secondary iron (hydr)oxide phases and remained in solid phases.The seasonal variability of acid volatile sulfide concentrations suggest the anoxic conditions are enhanced during summer by Spartina alterniflora compared to Phragmites australis and Scirpus mariqueter,causing a notable increase in As mobility.Generally,there was a typical variation in redox conditions with season in salt marsh sediments of Dongtan wetland,in which the dynamics of As mobility and transformation possibly were controlled by iron,and all of this could be significantly influenced by the rapid spread of S.alterniflora.

  8. Assessment of the use of sorbent amendments for reduction of mercury methylation in wetland sediments at Acadia National Park, Maine

    Science.gov (United States)

    Huntington, Thomas G.; Lewis, Ariel; Amirbahman, Aria; Marvin-DiPasquale, Mark C.; Culbertson, Charles W.

    2015-01-01

    Mercury is a contaminant of ecological concern because of its ubiquity and toxicity to fish and wildlife, and is considered a severe and ongoing threat to biota at Acadia National Park in Maine. The formation and biomagnification of methylmercury is the primary concern of resource managers at Acadia, and information is needed to develop strategies for remediation or mitigation of this contaminant. The U.S. Geological Survey in cooperation with Acadia National Park, National Park Service carried out a series of laboratory and field experiments to evaluate the potential of zero-valent iron and granular activated carbon to reduce the rate of the bacterially mediated process of mercury methylation and subsequent biological uptake by the great pond snail Lymnaea stagnalis. The addition of zero-valent iron resulted in an increase in ferrous iron that was then further oxidized to poorly crystalline amorphous ferric iron, as was anticipated. Our original hypothesis was that these reactions would reduce methylation by decreasing the concentrations of substrates for bacterial methylation (sulfide and divalent mercury) through sorption to ferric iron surfaces, formation of iron sulfide compounds, or conversion of mercury to gaseous forms and subsequent evasion. The results of our experiments did not consistently support this hypothesis. In one experiment the application of zero-valent iron increased the amount of methylmercury associated with surficial sediment. In another experiment zero-valent iron decreased the amount of methylmercury associated with surficial sediment. The addition of zero-valent iron may have stimulated mercury methylation by iron reducing bacteria and if that effect outweighed the processes that could have decreased methylation then methylation would not be decreased.

  9. Biogeochemistry of mercury and methylmercury in sediment cores from Sundarban mangrove wetland, India--a UNESCO World Heritage Site.

    Science.gov (United States)

    Chatterjee, Mousumi; Canário, João; Sarkar, Santosh Kumar; Branco, Vasco; Godhantaraman, Nallamuthu; Bhattacharya, Bhaskar Deb; Bhattacharya, Asokkumar

    2012-09-01

    This study was performed to elucidate the distribution, concentration trend and possible sources of total mercury (Hg(T)) and methylmercury (MeHg) in sediment cores (levels in sediments could be explained by sediment transport by the tidal Hugli (Ganges) River that would dilute the Hg(T) values via sediment mixing processes. A broader variation of MeHg proportions (%) were also observed in samples suggesting that other environmental variables such as organic carbon and microbial activity may play a major role in the methylation process. An overall elevated concentration of Hg(T) in surface layers (0-4 cm) of the core is due to remobilization of mercury from deeper sediments. Based on the index of geoaccumulation (I (geo)) and low effects-range (ER-L) values, it is considered that the sediment is less polluted by Hg(T) and there is less ecotoxicological risk. The paper provides the first information of MeHg in sediments from this wetland environment and the authors strongly recommend further examination of Hg(T) fluxes for the development of a detailed coastal MeHg model. This could provide more refine estimates of a total flux into the water column.

  10. The contribution of anammox and denitrification to sediment N2 production in a surface flow constructed wetland.

    Science.gov (United States)

    Erler, Dirk V; Eyre, Bradley D; Davison, Leigh

    2008-12-15

    This study used anaerobic slurry assays and intact core incubations to quantify potential rates of anammox (anaerobic ammonia oxidation) in sediments along the flow path of a surface flow constructed wetland receiving secondary treated sewage effluent. Anammox occurred at two of the four sites assayed with a maximum rate of 199.4 +/- 18.7 micromol N x m(-2) x hr(-1) (24% of total N2 production) at the discharge end of the wetland. Denitrification was the major producer of N2, with a maximum rate of 965.3 +/- 122.8 micromol N x m(-2) x hr(-1) at site 2. Oxygen was probably the key regulator of anammox activity within the studied CW. In addition to anammox, we found evidence that nitrifier-denitrification was potentially responsible for the production of N2O. Total production of N2O was 15.1% of the total gaseous N produced. Limitations to the methodology for quantifying anammox in CW's are outlined. This study demonstrated that denitrification is not the only pathway for gaseous production in constructed wetlands and that wetlands may be significant sources of greenhouse gases such as N2O.

  11. Sheet GT1-4. Radionuclides in sediments, bank soils and wetlands; Fiche GT1-4. Les radionucleides dans les sediments, les terres de berge et les zones humides

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-07-01

    This document reports investigations and measurements aimed at assessing the radiological quality of sediments, of bank soils, and of different wetlands, waterways and lakes located in the area of an ancient uranium mining site (La Crouzille, Limousin). As sediments are heterogeneous, sampling have been performed in several locations, and have been analysed in terms of activity with respect with depth

  12. Assessment of uncertainty in suspended sediment load at constructed wetland inlet and outlet

    Science.gov (United States)

    Eskelinen, Riku; Ronkanen, Anna-Kaisa; Marttila, Hannu; Kløve, Bjørn

    2016-04-01

    The use of constructed wetlands (CWs) for reducing pollution from different industries and land uses is common practice globally. Different countries have approached monitoring of CWs performance in several ways. For example, authorities can have different requirements in the flow measurement and sampling frequencies depending of the nature of the pollutant load. Typically, the load remaining after CW purification is estimated through concentration and flow measurements. As taking water samples comes with a cost, samples are taken with long intervals which can increase the uncertainty in the estimated loads. In 2012, a large water quality dataset was collected from CW inlet and outlet containing daily or twice a day water quality samples spanning from March until October. By sub-sampling the collected data with 1, 2, 3, or 4 weeks intervals we estimated the uncertainty range related to the sparse sampling. The results show large uncertainty remaining even with weekly sampling which suggests that increasing the sampling density from once in two weeks to once a week is not probably worth as the costs related to sampling would double. A method based on the flow duration curve (FDC) of the CW for reducing the uncertainty was also tested. The method divides the observed FDC to four equal parts and finds the mean or median concentration for each flow category. The load is then calculated by multiplying the observed flow with the mean or median concentration with the appropriate flow category. The FDC method was able to decrease the uncertainty, but much still remained, especially when concentrations of the measured variable showed large variation as it is typical case if annual nutrient and sediment loads from different land uses are monitored. Generally, continuous sensor technology might be a feasible option for further reducing the uncertainty in load estimation.

  13. Contemporary deposition and long-term accumulation of sediment and nutrients by tidal freshwater forested wetlands impacted by sea level rise

    Science.gov (United States)

    Noe, Gregory; Hupp, Cliff R.; Bernhardt, Christopher E.; Krauss, Ken W.

    2016-01-01

    Contemporary deposition (artificial marker horizon, 3.5 years) and long-term accumulation rates (210Pb profiles, ~150 years) of sediment and associated carbon (C), nitrogen (N), and phosphorus (P) were measured in wetlands along the tidal Savannah and Waccamaw rivers in the southeastern USA. Four sites along each river spanned an upstream-to-downstream salinification gradient, from upriver tidal freshwater forested wetland (TFFW), through moderately and highly salt-impacted forested wetlands, to oligohaline marsh downriver. Contemporary deposition rates (sediment, C, N, and P) were greatest in oligohaline marsh and lowest in TFFW along both rivers. Greater rates of deposition in oligohaline and salt-stressed forested wetlands were associated with a shift to greater clay and metal content that is likely associated with a change from low availability of watershed-derived sediment to TFFW and to greater availability of a coastal sediment source to oligohaline wetlands. Long-term accumulation rates along the Waccamaw River had the opposite spatial pattern compared to contemporary deposition, with greater rates in TFFW that declined to oligohaline marsh. Long-term sediment and elemental mass accumulation rates also were 3–9× lower than contemporary deposition rates. In comparison to other studies, sediment and associated nutrient accumulation in TFFW are lower than downriver/estuarine freshwater, oligohaline, and salt marshes, suggesting a reduced capacity for surface sedimentation (short-term) as well as shallow soil processes (long-term sedimentation) to offset sea level rise in TFFW. Nonetheless, their potentially large spatial extent suggests that TFFW have a large impact on the transport and fate of sediment and nutrients in tidal rivers and estuaries.

  14. Heavy metals in water, sediments and wetland plants in an aquatic ecosystem of tropical industrial region, India.

    Science.gov (United States)

    Rai, Prabhat Kumar

    2009-11-01

    Concentrations of heavy metals (Cu, Cr, Fe, Pb, Zn, Hg, Ni, and Cd) and macronutrients (Mn) were measured in industrial effluents, water, bottom sediments, and wetland plants from a reservoir, Govind Ballabh (G.B.) Pant Sagar, in Singrauli Industrial region, India. The discharge point of a thermal power plant, a coal mine, and chlor-alkali effluent into the G.B. Pant Sagar were selected as sampling sites with one reference site in order to compare the findings. The concentrations of heavy metals in filtered water, sieved sediment samples (0.4-63 microm), and wetland plants were determined with particle-induced X-ray emission. The collected plants were Aponogeton natans, L. Engl. & Krause, Cyperus rotundus, L., Hydrilla verticillata, (L.f.) Royle, Ipomoea aquatica, Forssk., Marsilea quadrifolia, L., Potamogeton pectinatus, L., Eichhornia crassipes, (Mart.) Solms Monogr., Lemna minor, L., Spirodela polyrhiza (L.) Schleid. Linnaea, Azolla pinnata, R.Br., Vallisneria spiralis, L., and Polygonum amphibium, L. In general, metal concentration showed a significant positive correlation between industrial effluent, lake water, and lake sediment (p macrophytes for pollution monitoring.

  15. Geologic-SURFICIAL62K-poly

    Data.gov (United States)

    Vermont Center for Geographic Information — The GeologicSurficial_SURFICIAL data consists of surficial geologic features as digitized from the 1:62,500 15 minute series USGS quadrangle map sheets, compiled by...

  16. Partitioning of heavy metals in the surface sediments of Quanzhou Bay wetland and its availability to Suaeda australis

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In order to investigate distributions of heavy metal pollution in Quanzhou Bay wetland, the total concentration and chemical partitioning of a number of heavy metals (Cu, Zn, Cd, Pb, Cr, Hg) in sediments of three sampling sites of Quanzhou Bay wetland and their availability to Suaeda australis were analyzed. The Geoaccumulation Index (Igeo) values reveal that the sediments of three sampling sites may all be considered as moderately contaminated for Pb and Zn, and all sediments might be strongly contaminated with cadmium. The partitioning analyses revealed the measured heavy metals in three sites are bound to the exchangeable fraction at lower concentrations. The measured metals in a considerable amount are bound to the reducible and oxidizable fractions, and a high proportion of the measured heavy metals were distributed in the residual fraction in the sediment samples. The concentrations of Cd in each chemical phase extracted from the sediments are above natural global background levels and should be further investigated because of its toxicity. Suaeda australis has different accumulation abilities for the measured heavy metals. For the root and stem, the bioaccumulation ability assessed by bioaccumulation factor (BA F) for the measured heavy metals follows the decreasing order as: Cu>Cr> Zn>Cd, Pb, Hg. In the leaf, stronger bioaccumulation ability for Hg is exhibited. The heavy metal concentrations in Suaeda australis roots have positive correlations with their available fractions, while the exchangeable fraction of Cu and Cd might have be more important to both mature plant roots and seedling roots uptake than other fractions; as for Cr, the oxidizable fraction might make a greater contribution to the plant root uptake; as for Zn, the reducible fraction might make so contribution; and for Pb, the oxidizable fraction might make a significant contribution to the mature plant root uptake, however, the exchangeable fraction might have a significant

  17. Analysis of heavy metals from water, sediment, and tissues of Labeo angra (Hamilton, 1822), from an Ox-box lake- an wetland site from Assam, India.

    Science.gov (United States)

    Das, Suchismita; Choudhury, Shamim Sultana

    2016-01-01

    The aim of this study was to assess the regional impacts of heavy metals (Mn, Fe, Mg, Ca, Cu, Zn, Cd, Cr, Pb and Ni) on water, sediment and a native, teleost fish species, Labeo angra, inhabiting a flood plain wetland of Barak River in Assam, India. Heavy metal concentrations in the water, sediments and fish were measured; bioaccumulation factor, metal pollution index as well as condition indices were calculated, to assess the pollution load and health status of the fish. Multivariate statistical analysis was used on wetland water and sediment heavy metals to ascertain the possible sources and seasonal variations of the pollutants. Results showed that most heavy metals in the wetland water and sediments exceeded the water (drinking and irrigation) and sediment quality guidelines, respectively. Seasonal variations were observed for geogenic heavy metals, Mn, Fe, Mg and Ca while no seasonal variations were observed for anthropogenic heavy metals, Cu, Cd, Cr, Pb and Ni. Multivariate statistical analysis showed that there was strong correlation between geogenic and anthropogenic heavy metals in water and sediment, both originating from the common anthropogenic sources. Accumulation of most of the metals in all the tissues was above the safe limits as recommended by the Food and Agriculture Organization. High bioaccumulation factors and metal pollution index for these metals in the different tissues revealed that metals were extensively bio-accumulated and bioconcentrated. Condition indices in fish from the wetland suggested metabolic abnormalities.

  18. Occurrence and sources of polychlorinated dibenzo-p-dioxins, dibenzofurans and dioxin-like polychlorinated biphenyls in surficial sediments of Lakes Superior and Huron

    Energy Technology Data Exchange (ETDEWEB)

    Shen Li; Gewurtz, Sarah B. [Department of Chemistry, Brock University, 500 Glenridge Avenue, St. Catharines, Ontario, L2S 3A1 (Canada); Ontario Ministry of the Environment, 125 Resources Road, Toronto, Ontario, M9P 3V6 (Canada); Reiner, Eric J.; MacPherson, Karen A.; Kolic, Terry M.; Khurana, Vin; Helm, Paul A.; Howell, E. Todd [Ontario Ministry of the Environment, 125 Resources Road, Toronto, Ontario, M9P 3V6 (Canada); Burniston, Debbie A. [Environment Canada, 867 Lakeshore Road, Burlington, Ontario, L7R 4A6 (Canada); Brindle, Ian D. [Department of Chemistry, Brock University, 500 Glenridge Avenue, St. Catharines, Ontario, L2S 3A1 (Canada); Marvin, Chris H. [Department of Chemistry, Brock University, 500 Glenridge Avenue, St. Catharines, Ontario, L2S 3A1 (Canada); Ontario Ministry of the Environment, 125 Resources Road, Toronto, Ontario, M9P 3V6 (Canada)], E-mail: chris.marvin@ec.gc.ca

    2009-04-15

    Concentrations and congener profile patterns of 2378-substituted PCDD/Fs and DLPCBs in offshore, nearshore and tributary sediments of Lakes Superior and Huron are reported, and spatial trends and source contributions assessed. PCDD/F concentrations ranged from 5 to 18 000 pg/g dw (Lake Superior) and 3 to 6100 pg/g dw (Lake Huron); DLPCBs ranged from 9 to 11 000 pg/g dw (Lake Superior) and 9 to 27 000 pg/g dw (Lake Huron). Our analysis indicated atmospheric deposition is a primary source to depositional areas of both lakes; however, greater PCDD/F and DLPCB concentrations were observed at several nearshore and tributary sites, and were attributed to corresponding land use in the watershed. Statistical analysis and pattern comparison suggested that industrial inputs mainly associated with wood treatment plants, pulp and paper mills, mining operations, and chlorine-based chemical manufacturing also contributed to contamination by PCDD/Fs and DLPCBs in certain nearshore and offshore areas of Lakes Superior and Huron. - Lake-wide 2378-PCDD/F and DLPCB concentrations, spatial trends, and congener patterns are first reported in Lakes Superior and Huron sediments.

  19. Spatial relations of mercury contents in Pike (Esox lucius) and sediments concentration of the Anzali wetland, along the southern shores of the Caspian Sea, Iran.

    Science.gov (United States)

    Zamani-Ahmadmahmoodi, Rasool; Bakhtiari, Alireza Riyahi; Rodríguez Martín, José Antonio

    2014-07-15

    In recent decades, the Anzali wetland has been threatened and destroyed by environmental pollution from several sources. The purpose of this study was to determine the possible relationships between mercury concentrations in Pike and their respective sediments within the assumed multiple activity center scales of Pike (100, 250 and 500 m in radius). To gain a better understanding spatial distribution pattern of Hg in sediments and to pursue the main purpose of this study, kriging (geostatistic spatial interpolation method) was applied. Poor relationships were found between mercury concentrations of Pike and sediments within the assumed multiple activity center scales of Pike. The mercury sediment influence diminished with the increasing radii of assumed activity centers. The results of the present study indicate that fish and sediment mercury concentrations in western parts of the Anzali wetland were low in comparison with the concentrations reported in the literature from other regions.

  20. Wetland biogeochemistry and ecological risk assessment

    Science.gov (United States)

    Bai, Junhong; Huang, Laibin; Gao, Haifeng; Zhang, Guangliang

    2017-02-01

    Wetlands are an important ecotone between terrestrial and aquatic ecosystems and can provide great ecological service functions. Soils/sediments are one of the important components of wetland ecosystems, which support wetland plants and microorganisms and influence wetland productivity. Moreover, wetland soils/sediments serve as sources, sinks and transfers of carbon, nitrogen, phosphorus and chemical contaminants such as heavy metals. In natural wetland ecosystems, wetland soils/sediments play a great role in improving water quality as these chemical elements can be retained in wetland soils/sediments for a long time. Moreover, the biogeochemical processes of the abovementioned elements in wetland soils/sediments can drive wetland evolution and development, and their changes will considerably affect wetland ecosystem health. Therefore, a better understanding of wetland soil biogeochemistry will contribute to improving wetland ecological service functions.

  1. Concentration of polybrominated diphenyl ethers (PBDEs) in sediment cores of Sundarban mangrove wetland, northeastern part of Bay of Bengal (India)

    Energy Technology Data Exchange (ETDEWEB)

    Binelli, Andrea [Department of Biology, University of Milan, Via Celoria 26, 20133 Milan (Italy)]. E-mail: andrea.binelli@unimi.it; Sarkar, Santosh Kumar [Department of Marine Science, University of Calcutta, 35 Ballygunge Circular Road, Calcutta 700 019 (India); Chatterjee, Mousumi [Department of Marine Science, University of Calcutta, 35 Ballygunge Circular Road, Calcutta 700 019 (India); Riva, Consuelo [Department of Biology, University of Milan, Via Celoria 26, 20133 Milan (Italy); Parolini, Marco [Department of Biology, University of Milan, Via Celoria 26, 20133 Milan (Italy); Bhattacharya, Bhaskar deb [Department of Marine Science, University of Calcutta, 35 Ballygunge Circular Road, Calcutta 700 019 (India); Bhattacharya, Asok Kumar [Department of Marine Science, University of Calcutta, 35 Ballygunge Circular Road, Calcutta 700 019 (India); Satpathy, Kamala Kanta [Indira Gandhi Center for Atomic Research, Environmental and Industrial Safety Section, Safety Group, Kalpakkam 603 102, Tamil Nadu (India)

    2007-08-15

    The paper presents the first comprehensive survey of congener profiles (12 congeners) of polybrominated diphenyl ethers (PBDEs) in core sediment samples (<63 {mu}m) covering seven sites in Sundarban mangrove wetland (India). Gas-chromatographic analyses were carried out in GC-Ms/Ms for tri- to hepta- brominated congeners. Results pointed out a non-homogenous contamination of the wetland with {sigma}{sub 12} PBDE values ranging from 0.08 to 29.03 ng g{sup -1}, reflecting moderate to low contamination closely in conformity to other Asian aquatic environments. The general order of decreasing congener contribution to the total load was: BDE 47 > 99 > 100 > 154, similar to the distribution pattern worldwide. Although tetrabromodiphenyl ether BDE 47 was found in all samples followed by hexabromodiphenyl ether BDE-154, they were not necessarily the dominant congeners. No uniform temporal trend on PBDE levels was recorded probably due to particular hydrological characteristics of the wetland and/on non-homologous inputs from point sources (untreated municipal wastewater and local industries, electronic wastes from the dump sites, etc.) of these compounds. Because of the propensity of PBDEs to accumulate in various compartments of wildlife and human food webs, evaluation of biological tissues should be undertaken as a high priority.

  2. Trapping runoff, sediment and nutrients at the edge-of-field: Using constructed wetlands to control runoff and improve water quality in agricultural catchments

    Science.gov (United States)

    Deasy, Clare; Quinton, John; Stoate, Chris

    2010-05-01

    Across Europe, many rivers and lakes are polluted. In the UK, the Biodiversity Action Plan estimates that over 70% of lakes are eutrophic. Diffuse pollution from agriculture is currently of extreme concern, but pollution and flood risk can be mitigated by management activities. The use of in-field mitigation options such as reduced tillage has been found to be effective at reducing runoff, sediment and nutrient loss in overland flow, but pollutants can still be lost from hillslopes unchecked via subsurface flow pathways, some of which may contribute very high loads of nutrients to streams. Edge-of-field mitigation approaches, which can tackle both surface and subsurface pathways at locations where they discharge into ditches and streams, therefore have greater potential as runoff control measures than in-field measures alone. In the UK, the implementation, effectiveness and functioning of seven new wetlands constructed at the edges of agricultural fields is currently being assessed. The constructed wetlands, of different designs, which are fed by different flow types and are located on different farm and soil types, are continuously monitored for discharge and turbidity at inlets and outlets, while storm sampling allows assessment of sediment and nutrient transfer into and out of the wetland at times when there is a high risk of pollutant transfer. Pond surveys and sediment sampling will take place annually, and tracer experiments will be carried out in the course of the project. The data will be used to generate information on sediment and nutrient load reductions or wetland effectiveness, wetland sediment and nutrient budgets, and water and sediment residence times. In this paper we present the initial results, including novel high-resolution data from the first monitored events. Early outputs suggest that constructed wetlands which receive surface runoff inputs can retain flood waters and may reduce flood peaks, wetlands built to take drain outfalls may be

  3. Combined effects of carbon, nitrogen and phosphorus on CH4 production and denitrification in wetland sediments

    NARCIS (Netherlands)

    Kim, Sang Yun; Veraart, Annelies; Meima-Franke, M.; Bodelier, Paul

    2015-01-01

    Anthropogenic impacts and associated climate change are anticipated to change nutrient availability in wetlands. Changes in nutrient availability can affect major biogeochemical reactions (i.e., methanogenesis, denitrification) which impact greenhouse gas emissions and trophic status of ecosystems.

  4. Long-term impact of hydrological regime on structure and functions of microbial communities in riverine wetland sediments.

    Science.gov (United States)

    Foulquier, Arnaud; Volat, Bernadette; Neyra, Marc; Bornette, Gudrun; Montuelle, Bernard

    2013-08-01

    In a context of global change, alterations in the water cycle may impact the structure and function of terrestrial and aquatic ecosystems. Wetlands are particularly at risk because hydrological regime has a major influence on microbially mediated biogeochemical processes in sediments. While the influence of water availability on wetland biogeochemical processes has been comprehensively studied, the influence of hydrological regime on microbial community structure has been overlooked. We tested for the effect of hydrological regime on the structure and functions of microbial communities by comparing sediments collected at multiple sites in the Ain département (Eastern France). Each site consisted of two plots, one permanently and one seasonally inundated. At the time of sampling, all plots were continuously inundated for more than 6 months but still harboured distinct bacterial communities. This change in community structure was not associated with marked modifications in the rates of microbial activities involved in the C and N cycles. These results suggest that the observed structural change could be related to bacterial taxa responding to the environmental variations associated with different hydrological regimes, but not strongly associated with the biogeochemical processes monitored here. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  5. Factors Influencing Microbial Carbon Emission Potential from Wetland Sediments and its Relation to Surface- and Plot-Scale Measurements

    Science.gov (United States)

    Brooker, M.; Bohrer, G.; Mouser, P. J.

    2012-12-01

    Wetlands provide valuable ecosystem services by sequestering carbon dioxide from the atmosphere and serving as a sink for atmospheric nitrogen export. They are often constructed as buffers between agriculture lands and drainage channels to improve runoff water quality from elevated nutrient loading (e.g. nitrate-N). Unfortunately, carbon sequestration and denitrification in wetlands come with the tradeoff of increased production of methane, another more potent green house gas. Existing models correlate methane emission rates to increased temperature; however, surface- and plot-scale measurements show little or weak relationships between these factors at the field scale. This study examines the relationship of several environmental factors - temperature, zone location, and microbial community - to methane emissions under controlled laboratory conditions. Water and sediments collected from two depths (0-6" and 6-12") and four distinct biomes (open water and three distinct emergent macrophyte covers) were used to prepare anaerobic microcosms at two different temperatures (20°C and 30°C). Headspace gas (methane, carbon dioxide), water chemistry, and microbial community composition were analyzed over the course of several months. We observed: 1) an increase in methane emission potential with higher temperature; 2) higher levels of methane produced from shallower sediments; 3) differential production of methane versus carbon dioxide depending upon biome; and 4) variations in bacterial and archaeal diversity relating to methane production rates. This data helps provide upper limit estimates for methane emissions from wetlands by methanogenic Archaea and informs our ability to better parameterize biogeochemical and atmospheric models of these systems.

  6. Surficial geology of the Cornell Dam 7.5 Minute Quadrangle, Nebraska

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The following is a surficial geology map of the Cornell Dam on the Niobrara River and surrounding area, near Valentine, Nebraska. This map shows the sediments and...

  7. Assessment of benthic flux of dissolved organic carbon in wetland and estuarine sediments using the eddy-correlation technique

    Science.gov (United States)

    Swett, M. P.; Amirbahman, A.; Boss, E.

    2009-12-01

    Wetland and estuarine sediments release significant amounts of dissolved organic carbon (DOC) due to high levels of microbial activity, particularly sulfate reduction. Changes in climate and hydrologic conditions have a potential to alter DOC release from these systems as well. This is a concern, as high levels of DOC can lead to mobilization of toxic metals and organics in natural waters. In addition, source waters high in DOC produce undesirable disinfection byproducts in water treatment. Various in situ methods, such as peepers and sediment core centrifugation, exist to quantify vertical benthic fluxes of DOC and other dissolved species from the sediment-water interface (SWI). These techniques, however, are intrusive and involve disturbance of the sediment environment. Eddy-correlation allows for real-time, non-intrusive, in situ flux measurement of important analytes, such as O2 and DOC. An Acoustic Doppler Velocimeter (ADV) is used to obtain three-dimensional fluid velocity measurements. The eddy-correlation technique employs the mathematical separation of fluid velocity into mean velocity and fluctuating velocity components, with the latter representing turbulent eddy velocity. DOC concentrations are measured using a colored dissolved organic matter (CDOM) fluorometer, and instantaneous vertical flux is determined from the correlated data. This study assesses DOC flux at three project sites: a beaver pond in the Lower Penobscot Watershed, Maine; a mudflat in Penobscot River, Maine; and a mudflat in Great Bay, New Hampshire. Eddy flux values are compared with results obtained using peepers and centrifugation, as well as vertical profiling.

  8. Toxicity of fungicides to natural bacterial communities in wetland water and sediment measured using leucine incorporation and potential denitrification.

    Science.gov (United States)

    Milenkovski, Susann; Bååth, Erland; Lindgren, Per-Eric; Berglund, Olof

    2010-02-01

    We assessed potential toxicity of fungicides to natural bacterial communities from a constructed wetland, located in southern Sweden, and compared the sensitivity of two endpoints indicating bacterial activity, leucine incorporation, and potential denitrification, in detecting toxicity. The effects of eight fungicides (benomyl, carbendazim, carboxin, captan, cycloheximide, fenpropimorph, propiconazole, and thiram), two bactericides (bronopol and chlortetracycline) as controls, and one reference compound (3,5-dichlorophenol), were tested in a water-sediment microcosm set-up. Leucine incorporation was measured in both the water and sediment column, while potential denitrification was measured for the entire microcosm. The bactericides and the reference compound gave sigmoid concentration-response curves for both endpoints in all but one case. The fungicides thiram, captan, and benomyl, and to a lesser extent fenpropimorph and propiconazole had quantifiable toxic effects on leucine incorporation, with EC(50) values ranging from 3 to 70 mg l(-1), while carbendazim, carboxin, and cycloheximide had little effect at the investigated concentrations. Only thiram and captan inhibited potential denitrification; the other fungicides showed no quantifiable effect. A greater toxic effect on leucine incorporation was recorded for bacterial communities associated with the water column, compared to the sediment column, for all tested compounds. Leucine incorporation was the more sensitive method for toxicity assessment of bacterial communities, and also allowed for a rapid and simple way of comparing exposure in the sediment and water column, making it an attractive standard method for community based toxicological assays in aquatic environments.

  9. Biogeochemical and hydrological controls in mobilizing Se in a saline wetland environment

    Science.gov (United States)

    Datta, S.; Hettiarachchi, G. M.; Crawford, M.; Karna, R.; Allmendinger, N. E.; Khatiwada, R.

    2010-12-01

    Selenium (Se) contamination in watersheds remains a challenge to water and land and wildlife managers throughout the west and mid west of US. In that sense, understanding the fundamentals of Se mobilization, fixation and bioconcentration is the current research endeavor. The challenge for Se research is developing watershed-geochemical models that are well founded in Se geochemical/biologcial principles that can be applied in a wide range of situations to inform decisions. Pariette Wetlands, a 9000 acre Bureau of Land Management controlled wetland system composed of 20 ponds located at the confluence of Pariette Draw and the Green River is the present location of this study. The agricultural and irrigation practices and the water-rock interactions leading to salinization can be associated with changes in Se chemistry in the rivers. Since its inception Pariette Wetlands has been home to a rich and diverse wetland ecosystem located in the arid Uintah Basin of Northeastern Utah. Detailed sampling of surficial sediments (0-1 m) from stream banks, channel beds and for water sampling have been undergone in 2 separate field trips throughout the entire reach of the wetland. To establish Pariette Draw’s contribution of Se to the Green river, water and sediments were also sampled from the Green River up and downstream of its confluence with Pariette Draw. In situ measurements of water parameters within the wetland suggest a clear trend of increased pH from upstream, 8, to downstream, 9.2 and combined with TDS suggest a pH controlled saline environment system. The headwaters near Flood Control Dam have an added input of Se from a possible irrigation source upstream in Pleasant Valley area while Se drastically decreases downstream towards the Red Head Pond. Se fractionation in sediments is being analyzed via a sequential extraction procedure to locate the labile fractions of mostly inorganic bound Se. Solid state speciation of Se via μ-XRF aided μ-XANES is being combined

  10. The distribution of organochlorine pesticides in sediments from iSimangaliso Wetland Park: Ecological risks and implications for conservation in a biodiversity hotspot.

    Science.gov (United States)

    Buah-Kwofie, Archibold; Humphries, Marc S

    2017-10-01

    The iSimangaliso Wetland Park World Heritage site, located on the east coast of South Africa, spans ∼3300 km(2) and constitutes the largest protected estuarine environment for hippopotami, crocodiles and aquatic birds in Africa. Given the ecological importance of this site and continued use of organochlorine pesticides (OCPs) in the region, this study focused on the nature, distribution and potential sources of organochlorine contamination within iSimangaliso Wetland Park. OCPs were widely distributed in surface sediment samples obtained from the four main Ramsar wetland systems within the park (Lake St Lucia, Mkhuze, Lake Sibaya and Kosi Bay). ∑HCH and ∑DDT were the dominant contaminants detected with concentrations in the range of 26.29-282.5 ng/g and 34.49-262.4 ng/g, respectively. ∑DDT concentrations revealed a distinctive gradient, with significantly higher concentrations at Kosi Bay and Lake Sibaya attributed to the application of DDT for malaria control. p,p'-DDE and p,p'-DDD were the dominant isomers detected, but the detection of p,p'-DDT in a number of samples reflects recent inputs of technical DDT. Highest concentrations of HCH, endosulfan and heptachlor were detected in sediments from Mkhuze and reflect the substantial residue load these wetlands receive from agricultural activities within the catchment area. Isomeric compositions indicate that endosulfan and heptachlor residues are derived mainly from historical application, while inputs of HCH, aldrin and endrin could be attributed to more recent usage at several sites. OCP sediment concentrations from iSimangaliso represent the highest yet recorded in South Africa and some of the highest reported globally this century. Sediments found within the lakes and wetlands of iSimangaliso represent large reservoirs of contaminants that pose ecotoxicological threats to this globally important biodiversity hotspot. Detailed investigation into the bioaccumulation and toxicological risks of OCPs within

  11. 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).

  12. Organic wastewater compounds in water and sediment in and near restored wetlands, Great Marsh, Indiana Dunes National Lakeshore, 2009–11

    Science.gov (United States)

    Egler, Amanda L.; Risch, Martin R.; Alvarez, David A.; Bradley, Paul M.

    2013-01-01

    A cooperative investigation between the U.S. Geological Survey and the National Park Service was completed from 2009 through 2011 to understand the occurrence, distribution, and environmental processes affecting concentrations of organic wastewater compounds in water and sediment in and near Great Marsh at the Indiana Dunes National Lakeshore in Beverly Shores, Indiana. Sampling sites were selected to represent hydrologic inputs to the restored wetlands from adjacent upstream residential and less developed areas and to represent discharge points of cascading cells within the restored wetland. A multiphase approach was used for the investigation. Discrete water samples and time-integrated passive samples were analyzed for 69 organic wastewater compounds. Continuous water-level information and periodic streamflow measurements characterized flow conditions at discharge points from restored wetland cells. Wetland sediments were collected and analyzed for sorptive losses of organic wastewater compounds and to evaluate of the potential for wetland sediments to biotransform organic wastewater compounds. A total of 52 organic wastewater compounds were detected in discrete water samples at 1 or more sites. Detections of organic wastewater compounds were widespread, but concentrations were generally low and 95 percent were less than 2.1 micrograms per liter. Six compounds were detected at concentrations greater than 2.1 micrograms per liter—four fecal sterols (beta-sitosterol, cholesterol, beta-stigmastanol, and 2-beta coprostanol), one plasticizer (bis-2-ethylhex ylphthalate), and a non-ionic detergent (4-nonylphenol diethoxylate). Two 1-month deployments of time-integrative passive samplers, called polar organic chemical integrative samplers, detected organic wastewater compounds at lower concentrations than were possible with discrete water samples. Isopropyl benzene (solvent), caffeine (plant alkaloid, stimulant), and hexahydrohexamethyl cyclopentabenzopyran (fragrance

  13. Distribution Characteristics of TOC, TN and TP in the Wetland Sediments of Longbao Lake in the San-Jiang Head Waters

    Science.gov (United States)

    Lu, Sujin; Si, Jianhua; Qi, Yue; Wang, Zhanqing; Wu, Xiaocui; Hou, Chuanying

    2016-12-01

    The study deals with the distribution of nutrients in wetland sediments, which provide the basis for revealing the wetland eutrophication processes and mechanisms of internal pollution sources. The total organic carbon (TOC), total nitrogen (TN), and total phosphorus (TP) contents and distribution characteristics of sediment samples were examined. The results showed that the TOC concentration ranged from 3.81 to 15.6 g/kg, the TN concentration ranged from 0.21 to 1.18 g/kg with a mean concentration of 0.66 g/kg, and the TP concentration ranged from 0.16 to 0.35 g/kg with a mean of 0.23 g/kg. Statistical analysis showed close correlations between TOC and TN (R2 = 0.96), and TN and TP (R2 = 0.97), which indicated that the TN and TP in the sediments were from similar sources. The concentrations of TOC, TN, and TP in Long-bao Lake wetland sediments were too low for eutrophication to occur. Our investigation indicated that Longbao Lake undergoes natural evolution rather than anthropogenic activities.

  14. Modeling of Waves, Hydrodynamics and Sediment Transport for Protection of Wetlands at Braddock Bay, New York

    Science.gov (United States)

    2015-03-01

    maximum wave heights near the backbay shoreline from the Jan 1971 storm for S-0, S-1, S-2, and S-3. Table 4-6 presents the calculated maxi - mum wave...decreases inside the bay. At the high water level, it appears wave overtopping pro- duces more flow in the lee of two structures, but flows are weak at...waves and currents significantly in the central backbay peninsula region preceding the wetlands. The maxi - mum wave height calculated for the Hurricane

  15. Microbial and chemical contamination of water, sediment and soil in the Nakivubo wetland area in Kampala, Uganda.

    Science.gov (United States)

    Fuhrimann, Samuel; Stalder, Michelle; Winkler, Mirko S; Niwagaba, Charles B; Babu, Mohammed; Masaba, Godfrey; Kabatereine, Narcis B; Halage, Abdullah A; Schneeberger, Pierre H H; Utzinger, Jürg; Cissé, Guéladio

    2015-07-01

    The reuse of domestic and industrial wastewater in urban settings of the developing world may harm the health of people through direct contact or via contaminated urban agricultural products and drinking water. We assessed chemical and microbial pollutants in 23 sentinel sites along the wastewater and faecal sludge management and reuse chain of Kampala, Uganda. Water samples were examined for bacteria (thermotolerant coliforms (TTCs), Escherichia coli and Salmonella spp.) and helminth eggs. Physico-chemical parameters were determined. Water, sediment and soil samples and edible plants (yams and sugar cane) were tested for heavy metals. Water samples derived from the Nakivubo wetland showed mean concentrations of TTCs of 2.9 × 10(5) colony-forming units (CFU)/100 mL. Mean E. coli was 9.9 × 10(4) CFU/100 mL. Hookworm eggs were found in 13.5% of the water samples. Mean concentrations of iron (Fe), copper (Cu) and cadmium (Cd) were 21.5, 3.3 and 0.14 mg/L, respectively. In soil samples, we found a mean lead (Pb) concentration of 132.7 mg/L. In yams, concentrations of Cd, chromium (Cr) and Pb were 4.4, 4.0 and 0.2 mg/L, while the respective concentrations in sugar cane were 8.4, 4.3 and 0.2 mg/L. TTCs and E. coli in the water, Pb in soil, and Cd, Cr and Pb in the plants were above national thresholds. We conclude that there is considerable environmental pollution in the Nakivubo wetland and the Lake Victoria ecosystem in Kampala. Our findings have important public health implications, and we suggest that a system of sentinel surveillance is being implemented that, in turn, can guide adequate responses.

  16. Assessment of suitability of macrobenthic mollusc diversity to monitor water quality and shallow sediment quality in a tropical rehabilitated and non-rehabilitated wetland system

    Directory of Open Access Journals (Sweden)

    W.M. Dimuthu Nilmini Wijeyaratne

    2017-06-01

    Full Text Available Six sampling sites were selected to represent different land use types in the rehabilitated and non-rehabilitated areas of a recreational wetland in Sri Lanka to study the suitability of macrobenthic mollusc diversity to monitor spatial and temporal variation in physico-chemical parameters of water and shallow sediments. Individuals belonging to six families and eight species were recorded during the study. The significantly highest mean abundance (individuals of Bithynia tentaculata and Pila globosa were recorded in sites from the rehabilitated area and there was no significant temporal variation of mollusc abundance during the study.  The abundance and diversity of mollusc community showed significant spatial variations and this study identified that B. tentaculata and P. globosa can be used as possible bioindicators to detect changes in water and shallow sediment quality in tropical wetland ecosystems

  17. Mercury contamination chronologies from Connecticut wetlands and Long Island Sound sediments

    Science.gov (United States)

    Varekamp, J.C.; Kreulen, B.; Buchholtz ten Brink, M. R.; Mecray, E.L.

    2003-01-01

    Sediment cores were used to investigate the mercury deposition histories of Connecticut and Long Island Sound. Most cores show background (pre-1800s) concentrations (50-100 ppb Hg) below 30-50 cm depth, strong enrichments up to 500 ppb Hg in the core tops with lower Hg concentrations in the surface sediments (200-300 ppb Hg). A sediment core from the Housatonic River has peak levels of 1,500 ppb Hg, indicating the presence of a Hg point source in this watershed. The Hg records were translated into Hg contamination chronologies through 210Pb dating. The onset of rig contamination occurred in ???1840-1850 in eastern Connecticut, whereas in the Housatonic River the onset is dated at around 1820. The mercury accumulation profiles show periods of peak contamination at around 1900 and at 1950-1970. Peak Hg* (Hg*= Hg measured minus Hg background) accumulation rates in the salt marshes vary, dependent on the sediment character, between 8 and 44 ng Hg/cm2 per year, whereas modern Hg* accumulation rates range from 4-17 ng Hg/cm2 per year; time-averaged Hg* accumulation rates are 15 ng Hg/cm2 per year. These Hg* accumulation rates in sediments are higher than the observed Hg atmospheric deposition rates (about 1-2 ng Hg/cm2 per year), indicating that contaminant Hg from the watershed is focused into the coastal zone. The Long Island Sound cores show similar Hg profiles as the marsh cores, but time-averaged Hg* accumulation rates are higher than in the marshes (26 ng Hg/cm2 a year) because of the different sediment characteristics. In-situ atmospheric deposition of Hg in the marshes and in Long Island Sound is only a minor component of the total Hg budget. The 1900 peak of Hg contamination is most likely related to climatic factors (the wet period of the early 1900s) and the 1950-1970 peak was caused by strong anthropogenic Hg emissions at that time. Spatial trends in total Hg burdens in cores are largely related to sedimentary parameters (amount of clay) except for the high

  18. Distribution and mobilization of pollutants in the sediment of a constructed floating wetland used for treatment of combined sewer overflow events

    OpenAIRE

    Van de Moortel, Annelies; Du Laing, Gijs; De Pauw, Niels; Tack, Filip

    2011-01-01

    Sediments in combined sewer overflow treatment systems may exhibit elevated pollutant concentrations. Concentrations measured in the sediment of a floating treatment wetland ranged from 0.17 to 1.6 (cadmium), 28 to 142 (copper), 10 to 33 (chromium), 50 to 141 (manganese), 5 to 20 (nickel), 50 to 203 (lead), and 185 to 804 (zinc) mg/kg dry matter and 7.4 to 17 (iron), 2 to 8 (total nitrogen), and 1.3 to 4.4 (total phosphorus) g/kg dry matter. During overflow events, the entering water volumes ...

  19. Provenance of the Quaternary Southern Kalahari sediments: A wetland that became dry

    Science.gov (United States)

    Vainer, Shlomy; Erel, Yigal; Matmon, Ari

    2017-04-01

    The ca. 140 Ma vast Kalahari basin is characterized by uplifted margins, terrestrial sedimentation within semi endorheic sub-basins, subdued morphology and tectonic quiescence. This intracratonic basin has been subjected to a prolonged period of subsidence affecting its sedimentary fill by changing plate motion and climatic cycles. Provenance studies of Kalahari Group sediments mainly focused on the easily accessible uppermost part that represents only the last phase of sedimentation, leaving unresolved questions for the rest of the strata. The Southern Kalahari Group succession exposed along the walls of the Mamatwan Mine, Northern Cape, South Africa, reveals three main depositional environments; a bottom pluvial, low-energy water body, a middle fluvial, high-energy environment and an upper aeolian sandy unit. The entire section, which was deposited within the Quaternary, records significant environmental and depositional changes suggesting a highly dynamic landscape. The fully exposed section (55 m) of the Kalahari Group at Mamatwan Mine was analysed for its mineralogy, elemental composition, Sr, Nd and Pb isotopic ratios and iron species. Mineralogical assemblage imply that a saline and alkaline shallow water-body existed during the early-middle Pleistocene contemporaneous with relative dense hominine occupation of the area. Isotopic ratios were used to determine the source of the sediments, which was found to be mainly of mafic rocks located to the north-east of Mamatwan. Weathering sensitive indices of both elemental ratios and iron phases show that sediments carried to the basin underwent considerable weathering indicative to a greater availability of surface water than the present. The lacustrine environment was rapidly filled with clasts that were derived mainly from the surrounding hills and experienced limited degree of chemical weathering during transport, but underwent subsequent groundwater alteration by iron-rich solution and precipitation of celcrete

  20. Retention and mitigation of metals in sediment, soil, water, and plant of a newly constructed root-channel wetland (China) from slightly polluted source water.

    Science.gov (United States)

    Wang, Baoling; Wang, Yu; Wang, Weidong

    2014-01-01

    Constructed root-channel wetland (CRCW) is a term for pre-pond/wetland/post-pond complexes, where the wetland includes plant-bed/ditch landscape and root-channel structure. Source water out of pre-ponds flows through alternate small ditches and plant beds with root-channels via a big ditch under hydraulic regulation. Then source water flows into post-ponds to finish final polishing. This article aims to explore the potential of components of a pilot CRCW in China on mitigating metals in micro-polluted source water during its initial operation stage. We investigated six heavy metals (Cd, Cr, Cu, Ni, Zn, and Pb) in surface sediment, plant-bed subsurface soil, water, and aquatic plants during 2012-2013. Monitoring results showed that pond/ditch sediments and plant-bed soil retained a significant amount of Cr, Ni, and Zn with 93.1%, 72.4%, and 57.5% samples showing contamination factor above limit 1 respectively. Remarkably the high values of metal enrichment factor (EF) occurred in root-channel zones. Water monitoring results indicated that Ni, Zn, and Pb were removed by 78.5% (66.7%), 57.6% (59.6%), and 26.0% (7.5%) in east (west) wetland respectively. Mass balance estimation revealed that heavy metal mass in the pond/ditch sediments accounted for 63.30% and that in plant-bed soil 36.67%, while plant uptake occupied only 0.03%. The heavy metal accretion flux in sediments was 0.41 - 211.08 μg · cm(-2) · a(-1), less than that in plant-bed soil (0.73 - 543.94 μg · cm(-2) · a(-1)). The 1.83 ha wetland has retained about 86.18 kg total heavy metals within 494 days after operation. This pilot case study proves that constructed root-channel wetland can reduce the potential ecological risk of purified raw water and provide a new and effective method for the removal of heavy metals from drinking water sources.

  1. Degradation of 1,1,2,2-tetrachloroethane and accumulation of vinyl chloride in wetland sediment microcosms and in situ porewater: Biogeochemical controls and associations with microbial communities

    Science.gov (United States)

    Lorah, M.M.; Voytek, M.A.

    2004-01-01

    The biodegradation pathways of 1,1,2,2-tetrachloroethane (TeCA) and 1,1,2-trichloroethane (112TCA) and the associated microbial communities in anaerobic wetland sediments were evaluated using concurrent geochemical and genetic analyses over time in laboratory microcosm experiments. Experimental results were compared to in situ porewater data in the wetland to better understand the factors controlling daughter product distributions in a chlorinated solvent plume discharging to a freshwater tidal wetland at Aberdeen Proving Ground, Maryland. Microcosms constructed with wetland sediment from two sites showed little difference in the initial degradation steps of TeCA, which included simultaneous hydrogenolysis to 112TCA and dichloroelimination to 1,2-dichloroethene (12DCE). The microcosms from the two sites showed a substantial difference, however, in the relative dominance of subsequent dichloroelimination of 112TCA. A greater dominance of 112TCA dichloroelimination in microcosms constructed with sediment that was initially iron-reducing and subsequently simultaneously iron-reducing and methanogenic caused approximately twice as much vinyl chloride (VC) production as microcosms constructed with sediment that was methanogenic only throughout the incubation. The microcosms with higher VC production also showed substantially more rapid VC degradation. Field measurements of redox-sensitive constituents, TeCA, and its anaerobic degradation products along flowpaths in the wetland porewater also showed greater production and degradation of VC with concurrent methanogenesis and iron reduction. Molecular fingerprinting indicated that bacterial species [represented by a peak at a fragment size of 198 base pairs (bp) by MnlI digest] are associated with VC production from 112TCA dichloroelimination, whereas methanogens (190 and 307 bp) from the Methanococcales or Methanobacteriales family are associated with VC production from 12DCE hydrogenolysis. Acetate-utilizing methanogens

  2. Comparison of monometal and multimetal adsorption in Mississippi River alluvial wetland sediment: batch and column experiments.

    Science.gov (United States)

    Seo, Dong Cheol; Yu, Kewei; DeLaune, Ronald D

    2008-12-01

    Monometal and multimetal adsorption of selected heavy metals in a sediment from a coastal Louisiana forested swamp used for wastewater treatment was studied. Results from the batch experiments show that the maximum adsorption capacities of the metals by the sediment were in the order of Pb>Hg>Cr>CdCuZn>As based on monometal adsorption isotherm, and Hg>Cr>CuCd approximately Pb>As approximately Zn based on multimetal adsorption isotherm, respectively. Batch experimental data best fit the Langmuir model rather than the Freundlich isotherms. In the column experiments, the maximum adsorption capacities of the metals were in the order of Pb>Hg>Cr>Cd>Cu>Zn>As in monometal conditions, and Hg>Cr>Pb>CuZn approximately Cd>As in multimetal conditions. The metals became more mobile in multimetal than in monometal conditions. Results from both the batch and column experiments show that competitive adsorption among metals increases the mobility of these metals. Particularly, in this study, Pb in multimetal conditions lost it adsorption capacity most significantly. In both monometal and multimetal conditions, the maximum adsorption capacity of the metals in the column experiments was higher than that in the batch experiment indicating other metal retention mechanisms rather than adsorption may be involved. Therefore, both column and batch experiments are needed for estimating retention capacities and removal efficiencies of metals in sediments.

  3. Pulsed Discharge Through Wetland Vegetation as a Control on Bed Shear Stress and Sediment Transport Affecting Everglades Restoration

    Science.gov (United States)

    Larsen, L. E.; Harvey, J. W.; Crimaldi, J. P.

    2007-12-01

    depth is not likely to increase water velocity and entrainment, it is necessary instead that restoration focus on increasing energy slope as a means to entrain sediment within sloughs and redistribute it to ridges. Surface-water gravity waves caused by hurricanes or pulsed releases of water from impounded areas may be the most effective mechanism for achieving sediment redistribution in the Everglades and other wetland and riparian environments with abundant emergent vegetation.

  4. Seasonal prevalence of Clostridium botulinum type C in the sediments of the northern California wetland

    Science.gov (United States)

    Sandler, Renee J.; Rocke, T.E.; Samuel, M.D.; Yuill, Thomas M.

    1993-01-01

    The prevalence of Clostridium botulinum type C (% of positive sediment samples) was determined in 10 marshes at Sacramento National Wildlife Refuge (SNWR), located in the Central Valley of California (USA), where avian botulism epizootics occur regularly. Fifty-two percent of 2,200 sediment samples collected over an 18-mo period contained C. botulinum type C (both neurotoxic and aneurotoxic) which was present throughout the year in all 10 marshes. The prevalence of C. botulinum type C was similar in marshes with either high or low botulism losses in the previous 5 yr. Marshes with avian botulism mortality during the study had similar prevalences as marshes with no mortality. However, the prevalence of C. botulinum type C was higher in marshes that remained flooded all year (permanent) compared with marshes that were drained in the spring and reflooded in the fall (seasonal). The prevalence of C. botulinum type C declined in seasonal marshes during the dry period. Similar declines did not occur in the permanently flooded marshes.

  5. Spatial distribution of cadmium and lead in the sediments of the western Anzali wetlands on the coast of the Caspian Sea (Iran).

    Science.gov (United States)

    Zamani-Ahmadmahmoodi, Rasool; Esmaili-Sari, Abbas; Mohammadi, Jahangard; Bakhtiari, Alireza Riyahi; Savabieasfahani, Mozhgan

    2013-09-15

    Spatial distribution patterns of total cadmium (Cd) and lead (Pb), their bioavailable fractions and total organic matter in sediment from Anzali wetlands are provided. Total sediment Pb was higher than Cd (34.95 versus 0.024 μg/g dry weight). The geoaccumulation index indicated that the sediment was "uncontaminated", but some stations were categorized as "unpolluted" to "moderately polluted". Less than 0.01 of Pb existed in exchangeable and carbonate fractions. The sum of exchangeable and carbonate-bound fractions of Cd was 42%, suggesting that Cd poses high risk to the aquatic ecosystems. Total Cd and Pb exhibited positive relationships with total organic matter. Considering spatial distribution maps of total and bioavailable fractions of metals suggested that high concentrations of metals does not necessarily indicate high bioavailable fraction. The methodologies we used in this study can be in more effective management of aquatic ecosystems, as well as ecological risk assessment of metals, and remediation programs.

  6. Records of pan (floodplain wetland) sedimentation as an approach for post-hoc investigation of the hydrological impacts of dam impoundment: The Pongolo river, KwaZulu-Natal.

    Science.gov (United States)

    Heath, S K; Plater, A J

    2010-07-01

    River impoundment by dams has far-reaching consequences for downstream floodplains in terms of hydrology, water quality, geomorphology, ecology and ecosystem services. With the imperative of economic development, there is the danger that potential environmental impacts are not assessed adequately or monitored appropriately. Here, an investigation of sediment composition of two pans (floodplain wetlands) in the Pongolo River floodplain, KwaZulu-Natal, downstream of the Pongolapoort dam constructed in 1974, is considered as a method for post-hoc assessment of the impacts on river hydrology, sediment supply and water quality. Bumbe and Sokhunti pans have contrasting hydrological regimes in terms of their connection to the main Pongolo channel - Bumbe is a shallow ephemeral pan and Sokhunti is a deep, perennial water body. The results of X-ray fluorescence (XRF) geochemical analysis of their sediment records over a depth of >1 m show that whilst the two pans exhibit similar sediment composition and variability in their lower part, Bumbe pan exhibits a shift toward increased fine-grained mineral supply and associated nutrient influx at a depth of c. 45 cm whilst Sokhunti pan is characterised by increased biogenic productivity at a depth of c. 26 cm due to enhanced nutrient status. The underlying cause is interpreted as a shift in hydrology to a 'post-dam' flow regime of reduced flood frequencies with more regular baseline flows which reduce the average flow velocity. In addition, Sokhunti shows a greater sensitivity to soil influx during flood events due to the nature of its 'background' of autochthonous biogenic sedimentation. The timing of the overall shift in sediment composition and the dates of the mineral inwash events are not well defined, but the potential for these wetlands as sensitive recorders of dam-induced changes in floodplain hydrology, especially those with a similar setting to Sokhunti pan, is clearly demonstrated. Copyright 2010 Elsevier Ltd. All

  7. Surficial geologic map of the Red Rock Lakes area, southwest Montana

    Science.gov (United States)

    Pierce, Kenneth L.; Chesley-Preston, Tara L.; Sojda, Richard L.

    2014-01-01

    The Centennial Valley and Centennial Range continue to be formed by ongoing displacement on the Centennial fault. The dominant fault movement is downward, creating space in the valley for lakes and the deposition of sediment. The Centennial Valley originally drained to the northeast through a canyon now represented by a chain of lakes starting with Elk Lake. Subsequently, large landslides blocked and dammed the drainage, which created Lake Centennial, in the Centennial Valley. Sediments deposited in this late Pleistocene lake underlie much of the valley floor and rest on permeable sand and gravel deposited when the valley drained to the northeast. Cold Pleistocene climates enhanced colluvial supply of gravelly sediment to mountain streams and high peak flows carried gravelly sediment into the valley. There, the lower gradient of the streams resulted in deposition of alluvial fans peripheral to Lake Centennial as the lake lowered through time to the level of the two present lakes. Pleistocene glaciers formed in the high Centennial Range, built glacial moraines, and also supplied glacial outwash to the alluvial fans. Winds from the west and south blew sand to the northeast side of the valley building up high dunes. The central part of the map area is flat, sloping to the west by only 0.6 meters in 13 kilometers (2 feet in 8 miles) to form a watery lowland. This lowland contains Upper and Lower Red Rock Lakes, many ponds, and peat lands inside the “water plane,” above which are somewhat steeper slopes. The permeable sands and gravels beneath Lake Centennial sediments provide a path for groundwater recharged from the adjacent uplands. This groundwater leaks upward through Lake Centennial sediments and sustains wetland vegetation into late summer. Upper and Lower Red Rock Lakes are formed by alluvial-fan dams. Alluvial fans converge from both the south and the north to form outlet thresholds that dam the two shallow lakes upstream. The surficial geology aids in

  8. The role of critical zone processes in the evolution of the Prairie Pothole Region wetlands

    Science.gov (United States)

    Goldhaber, M.B.; Mills, C.; Stricker, C.A.; Morrison, J.M.

    2011-01-01

    The Prairie Pothole Region, which occupies 900,000 km2 of the north central USA and south central Canada, is one of the most important ecosystems in North America. It is characterized by millions of small wetlands whose chemistry is highly variable over short distances. The study involved the geochemistry of surface sediments, wetland water, and groundwater in the Cottonwood Lakes area of North Dakota, USA, whose 92 ha includes the dominant wetland hydrologic settings. The data show that oxygenated groundwater interacting with pyrite resident in a component of surficial glacial till derived from the marine Pierre Shale Formation has, over long periods of time, focused SO2-4-bearing fluids from upland areas to topographically low areas. In these low areas, SO2-4-enriched groundwater and wetlands have evolved, as has the CaSO4 mineral gypsum. Sulfur isotope data support the conclusion that isotopically light pyrite from marine shale is the source of SO2-4. Literature data on wetland water composition suggests that this process has taken place over a large area in North Dakota.

  9. Nitrogen and Sediment Capture of a Floating Treatment Wetland on an Urban Stormwater Retention Pond—The Case of the Rain Project

    Directory of Open Access Journals (Sweden)

    Brendan McAndrew

    2016-09-01

    Full Text Available Nitrogen is widely recognized as a chronic urban stormwater pollutant. In the United States, wet retention ponds have become widely used to treat urban runoff for quantity and quality. While wet ponds typically function well for the removal of sediments, nitrogen removal, performance can be inconsistent due to poor design and/or lack of maintenance. Retrofitting ponds to improve their nitrogen capture performance, however, is often expensive. By hydroponically growing macrophytes on wet ponds, floating treatment wetlands (FTW may provide a cheap, sustainable means of improving nitrogen removal efficiency of aging stormwater ponds. Few studies have been performed on the effectiveness real-world stormwater systems, however. In this study, we investigated the nitrogen and sediment capture performance of a 50 m2 floating treatment wetland deployed for 137 days on a stormwater wet pond located within an urban university campus near Washington, D.C. A total of 2684 g of biomass was produced, 3100 g of sediment captured, and 191 g of nitrogen removed from the pond. Although biomass production was relatively low (53 g/m2, we found that nitrogen uptake by the plants (0.009 g/m2/day was comparable to contemporary FTW studies.

  10. Geologic-SURFICIAL62K-Sand and gravel pits

    Data.gov (United States)

    Vermont Center for Geographic Information — The GeologicSurficial_SURFICIAL data consists of surficial geologic features as digitized from the 1:62,500 15 minute series USGS quadrangle map sheets, compiled by...

  11. Geologic-SURFICIAL62K-Rocklines-Striations-Till-Fabric

    Data.gov (United States)

    Vermont Center for Geographic Information — The GeologicSurficial_SURFICIAL data consists of surficial geologic features as digitized from the 1:62,500 15 minute series USGS quadrangle map sheets, compiled by...

  12. Distribution and mobilization of pollutants in the sediment of a constructed floating wetland used for treatment of combined sewer overflow events.

    Science.gov (United States)

    Van de Moortel, Annelies M K; Du Laing, Gijs; De Pauw, Niels; Tack, Filip M G

    2011-05-01

    Sediments in combined sewer overflow treatment systems may exhibit elevated pollutant concentrations. Concentrations measured in the sediment of a floating treatment wetland ranged from 0.17 to 1.6 (cadmium), 28 to 142 (copper), 10 to 33 (chromium), 50 to 141 (manganese), 5 to 20 (nickel), 50 to 203 (lead), and 185 to 804 (zinc) mg/kg dry matter and 7.4 to 17 (iron), 2 to 8 (total nitrogen), and 1.3 to 4.4 (total phosphorus) g/kg dry matter. During overflow events, the entering water volumes can disturb the sediments. A greenhouse experiment was set up to evaluate the possible mobilization of pollutants through disturbation. The disturbation did not result in an increased mobilization of cadmium, copper, chromium, nickel, lead, zinc, nitrogen, phosphorus, and organic carbon towards the pore and surface water. Calcium concentrations in the surface water increased for all sediments, as a result of release from the exchangeable sediment pool and dissolution of carbonates. Geochemical speciation modeling indicated that, in the pore water, the free ion form was the most abundant for calcium, iron, manganese, cadmium, and nickel, with its fraction increasing with time.

  13. Mercury and methylmercury in water and bottom sediments of wetlands at Lostwood National Wildlife Refuge, North Dakota 2003-04

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Certain ecosystem types, particularly wetlands, have environmental characteristics that can make them particularly sensitive to mercury inputs and that can result in...

  14. Channel, Floodplain, And Wetland Responses To Floods And Overbank Sedimentation, 1846-2006, Halfway Creek Marsh, Upper Mississippi Valley, Wisconsin

    Science.gov (United States)

    Conversion of upland forest and prairie vegetation to agricultural land uses, following Euro-American settlement in the Upper Mississippi River System, led to accelerated runoff and soil erosion that subsequently transformed channels, floodplains, and wetlands on bottomlands. Ha...

  15. Degradation of 1,1,2,2-Tetrachloroethane by Microbial Consortia in Wetland Sediment: Controls on 1,2-Dichloroethane and Vinyl Chloride Accumulation

    Science.gov (United States)

    Lorah, M. M.; Voytek, M. A.

    2001-05-01

    Concurrent geochemical analyses of porewater and genetic analyses of wetland sediment over time in laboratory microcosm experiments are being used to define biodegradation pathways of 1,1,2,2-tetrachloroethane (PCA) and associated critical microorganisms in anaerobic wetland sediments. These experiments were conducted to better understand factors controlling in situ daughter product distribution as part of a study of natural attenuation of a chlorinated solvent plume that is discharging to a freshwater tidal wetland at Aberdeen Proving Ground, Maryland. Possible biodegradation pathways of PCA under anaerobic conditions include (1) sequential hydrogenolysis of PCA to 1,1,2-trichloroethane (TCA), 1,2-dichloroethane (DCA), chloroethane, and ethane; (2) hydrogenolysis of PCA to TCA followed by dichloroelimination of TCA to vinyl chloride (VC); and (3) dichloroelimination of PCA to cis- and trans-1,2-dichloroethene (DCE) and subsequent hydrogenolysis of DCE to VC. Elucidation of factors controlling the occurrence of these diverse pathways is critical because of differing toxicity and persistence of the daughter products. Microcosm experiments were conducted in March and July 1999 using wetland sediment and porewater collected at two contaminated sites in the study area-one characterized as predominantly methanogenic (WB23) and one characterized as mixed iron-reducing and methanogenic (WB30)-and amended only with PCA or TCA. Microcosm water was analyzed for volatile organic compounds, methane, ferrous iron, and sulfate, while genetic analyses of the corresponding microcosm sediment were used to obtain profiles of bacteria and methanogenic communities at each time step. All PCA-amended microcosms showed simultaneous production of TCA (from hydrogenolysis) and DCE (from dichloroelimination) from day 1. Subsequently, DCA became the predominant daughter product in microcosms constructed with WB23 sediment, which showed high methane production throughout the experiment

  16. Mercury, Methylmercury, and Other Constituents in Sediment and Water from Seasonal and Permanent Wetlands in the Cache Creek Settling Basin and Yolo Bypass, Yolo County, California, 2005-06

    Science.gov (United States)

    Marvin-DiPasquale, Mark; Alpers, Charles; Fleck, Jacob

    2009-01-01

    This report presents surface water and surface (top 0-2 cm) sediment geochemical data collected during 2005-2006, as part of a larger study of mercury (Hg) dynamics in seasonal and permanently flooded wetland habitats within the lower Sacramento River basin, Yolo County, California. The study was conducted in two phases. Phase I represented reconnaissance sampling and included three locations within the Cache Creek drainage basin; two within the Cache Creek Nature Preserve (CCNP) and one in the Cache Creek Settling Basin (CCSB) within the creek's main channel near the southeast outlet to the Yolo Bypass. Two additional downstream sites within the Yolo Bypass Wildlife Area (YBWA) were also sampled during Phase I, including one permanently flooded wetland and one seasonally flooded wetland, which had began being flooded only 1-2 days before Phase I sampling. Results from Phase I include: (a) a negative correlation between total mercury (THg) and the percentage of methylmercury (MeHg) in unfiltered surface water; (b) a positive correlation between sediment THg concentration and sediment organic content; (c) surface water and sediment THg concentrations were highest at the CCSB site; (d) sediment inorganic reactive mercury (Hg(II)R) concentration was positively related to sediment oxidation-reduction potential and negatively related to sediment acid volatile sulfur (AVS) concentration; (e) sediment Hg(II)R concentrations were highest at the two YBWA sites; (f) unfiltered surface water MeHg concentration was highest at the seasonal wetland YBWA site, and sediment MeHg was highest at the permanently flooded YBWA site; (g) a 1,000-fold increase in sediment pore water sulfate concentration was observed in the downstream transect from the CCNP to the YBWA; (h) low sediment pore water sulfide concentrations (<1 umol/L) across all sites; and (i) iron (Fe) speciation data suggest a higher potential for microbial Fe(III)-reduction in the YBWA compared to the CCSB. Phase II

  17. Dichloroethene and Vinyl Chloride Degradation Potential in Wetland Sediments at Twin Lakes and Pen Branch, Savannah River National Laboratory, South Carolina

    Science.gov (United States)

    Bradley, Paul M.

    2007-01-01

    A series of 14C-radiotracer-based microcosm experiments was conducted to assess the mechanisms and products of degradation of dichloroethene (DCE) and vinyl chloride (VC) in wetland sediments at the Department of Energy (DOE) Savannah River National Laboratory. This project investigated the potential for biotic and abiotic DCE and VC degradation in wetland sediments from the Twin Lakes area of the C-BRP investigative unit and from the portion of Pen Branch located directly down gradient from the CMP investigative unit. Substantial degradation of [1,2-14C] DCE and [1,2-14C] VC to 14CO2 was observed in all viable sediment microcosms prepared under oxic conditions. These results indicate that microbial mineralization processes, involving direct oxidation or cometabolic oxidation, are the primary mechanisms of DCE and VC biodegradation in Twin Lake and Pen Branch sediments under oxic conditions. Substantial degradation of [1,2-14C] DCE and [1,2-14C] VC was observed in all viable sediment microcosms incubated under anoxic conditions. Production of 14CO2 was observed in all sediment microcosms under anoxic conditions. In general, the accumulation of mineralization products (14CO2 and 14CH4) was comparable to the accumulation of those reduced daughter products (14C-VC, 14C-ethene or 14C-ethane) traditionally identified with chloroethene reductive dechlorination. These results indicate that microbial mineralization processes can be an important component of DCE and VC degradation in Twin Lake and Pen Branch sediments under anoxic conditions. These results demonstrate that an evaluation of the efficiency of in situ DCE and VC biodegradation in Twin Lakes and Pen Branch that is based solely on the observed accumulation of reduced daughter products may underestimate substantially the total extent of contaminant biodegradation and, thus, the contribution of biodegradation to overall contaminant attenuation. No evidence of abiotic degradation of [1,2-14C] DCE or [1,2-14C] VC

  18. [Mercury and copper accumulation during last fifty years and their potential ecological risk assessment in sediment of mangrove wetland of Shenzhen, China].

    Science.gov (United States)

    Li, Rui-Li; Chai, Min-Wei; Qiu, Guo-Yu; He, Bei

    2012-12-01

    The processes of sediment transport and deposition can record some relative anthropogenic information in gulf region. Chronological analysis of the sediment core collected from mangrove wetland in Shenzhen Bay showed that the sedimentation rate was about 1.38 cm x a(-1). Soil buck density, pH, electrical conductivity (EC) and total organic carbon (TOC) changed in range of 0.36-0.71 g x cm(-3), 6-7, 2.93 x 10(3) -4.97 x 10(3) microS x cm(-1), and 1.5% - 3.8%, respectively. With the increase of soil depth, the soil buck density and EC increased gradually. However, the TOC decreased, with no significant change of pH. Contents of Hg and Cu in the whole depth of core ranged between 92-196 ng x g(-1) and 29-83 microg x g(-1), respectively. And both of them in sediment increased firstly and then decreased with the increasing soil depth. At 14 cm depth, contents of Hg and Cu reached up to the highest levels. Correspondingly, the ecological risk of Hg and Cu changed similarly with the contents of Hg and Cu. At 14 cm depth, the ecological risk indexes of Hg and Cu were at the highest levels of 39.10 and 13.85, respectively. The potential ecological risks of both Hg and Cu in sediments were mild. The rapid economical development of Hong Kong in 1960-1985 and Shenzhen in 1985-2000 contributed much to the Hg and Cu accumulation in mangrove wetland of Shenzhen Bay, China. Since the year of 2000, the reduction in contents of Hg and Cu has been expected as a consequence of the adoption of contamination control policies, improving the environment for growth of mangrove. In conclusion, the variations of core sediment heavy metal contents and its ecological risk assessment along the vertical profile reveal the interaction processes and extent of anthropogenic influences from the areas around the Shenzhen Bay and the catchments.

  19. Surficial Geology of the Mosier Creek Basin

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A surficial and structural geologic map (SIR-2012-5002, fig. 2) was compiled to aid in the building of the three-dimensional geologic model. The map covers 327...

  20. Factors controlling temporal and spatial distribution of total mercury and methylmercury in hyporheic sediments of the Allequash Creek wetland, northern Wisconsin

    Science.gov (United States)

    Creswell, Joel E.; Kerr, Sara C.; Meyer, Matthew H.; Babiarz, Christopher L.; Shafer, Martin M.; Armstrong, David E.; Roden, Eric E.

    2008-06-01

    Hyporheic pore water samples were collected from two sites within the Allequash Creek wetland, in Vilas County, northern Wisconsin, from August 2003 to October 2004. Samples were collected simultaneously at the surface and at 2, 5, 7, 10, and 15 cm below the sediment-water interface. Concentration ranges were 3.7 to 58 pM for inorganic mercury, <0.5 to 16 pM for methylmercury, 3.02 to 152 μM and 0.38 to 96.6 μM for oxidized and reduced iron, respectively, 1.28 to 48.2 μM and< 0.05 to 9.76 μM for oxidized and reduced sulfur, respectively, and 109 to 689 μM for dissolved organic carbon. These concentrations are typical of anoxic environments such as wetlands and lake sediments. These data were used to gain a better understanding of the processes controlling spatial and temporal variability of inorganic mercury and methylmercury. Findings show that conditions conducive to mercury methylation exist in the hyporheic zone, especially in late summer, when accumulation of reduced iron and sulfide are indicative of microbial iron and sulfate reduction. Methylmercury concentrations also peak in late summer, with the highest concentrations appearing 2 to 10 cm below the sediment-water interface. While there is a general covariance of total mercury and methylmercury over the depth profile, poor correlation was observed over time, highlighting the dynamic nature of hyporheic zone conditions and suggesting changes in mercury speciation and partitioning.

  1. Water- and Bed-Sediment Quality of Seguchie Creek and Selected Wetlands Tributary to Mille Lacs Lake in Crow Wing County, Minnesota, October 2003 to October 2006

    Science.gov (United States)

    Fallon, James D.; Yaeger, Christine S.

    2009-01-01

    Mille Lacs Lake and its tributaries, located in east-central Minnesota, are important resources to the public. In addition, many wetlands and lakes that feed Mille Lacs Lake are of high resource quality and vulnerable to degradation. Construction of a new four-lane expansion of U.S. Highway 169 has been planned along the western part of the drainage area of Mille Lacs Lake in Crow Wing County. Concerns exist that the proposed highway could affect the resource quality of surface waters tributary to Mille Lacs Lake. Baseline water- and bed-sediment quality characteristics of surface waters tributary to Mille Lacs Lake were needed prior to the proposed highway construction. The U.S. Geological Survey, in cooperation with the Minnesota Department of Transportation, characterized the water- and bed-sediment quality at selected locations that the proposed route intersects from October 2003 to October 2006. Locations included Seguchie Creek upstream and downstream from the proposed route and three wetlands draining to Mille Lacs Lake. The mean streamflow of Seguchie Creek increased between the two sites: flow at the downstream streamflow-gaging station of 0.22 cubic meter per second was 5.6 percent greater than the mean streamflow at the upstream streamflow-gaging station of 0.21 cubic meter per second. Because of the large amount of storage immediately upstream from both gaging stations, increases in flow were gradual even during intense precipitation. The ranges of most constituent concentrations in water were nearly identical between the two sampling sites on Seguchie Creek. No concentrations exceeded applicable water-quality standards set by the State of Minnesota. Dissolved-oxygen concentrations at the downstream gaging station were less than the daily minimum standard of 4.0 milligrams per liter for 6 of 26 measurements. Constituent loads in Seguchie Creek were greater at the downstream site than the upstream site for all measured, including dissolved chloride (1

  2. [Spatiotemporal variation characteristics of heavy metals pollution in the water, soil and sediments environment of the Lean River-Poyang Lake Wetland].

    Science.gov (United States)

    Jian, Min-Fei; Li, Ling-Yu; Xu, Peng-Fei; Chen, Pu-Qing; Xiong, Jian-Qiu; Zhou, Xue-Ling

    2014-05-01

    Overlying water, sediments, surface soils in the typical wetland areas of Lean River and Poyang Lake which were rich in non-ferrous metal mineral resources on both sides of the river, were chosen for monitoring heavy metals including copper, lead and cadmium of base flow in average season, flood season, and dry season in 2012. Statistical analysis methods were coupled to characterize the spatiotemporal variation of heavy metals pollution and identify the main sources. The results indicated that the concentrations of copper were the highest in all samples of each sampling sites in the Lean River-Poyang Lake wetland. And the content values of copper, lead and cadmium in different samples of different sampling sites also showed that the content values of copper were higher than those of lead, and the content values of lead were also higher than those of cadmium. The results also showed that the heavy metals pollution of copper, lead and cadmium in flood season was the heaviest whereas the heavy metals pollution in dry season was comparatively light. The results of the contents of the three kinds of heavy metals elements in different sampling sites of the watersheds of lean River showed that the contents of copper in the samples from the upstream sampling sites of Lean River were higher than those of other samples from other sites. And the contents of lead in the samples from the downstream sampling sites of Lean River were higher than those of other samples from other sampling sites. The contents of cadmium in the samples from the midstream sampling sites of Lean River were higher than those of other samples from other sites. The first principal component representing copper pollution explained 36. 99% of the total variance of water quality. The second principal component concerning representing lead pollution explained 30. 12% of the total variance. The correlation analysis results showed that there were significant positive correlations among the contents of copper

  3. Effects of Amendments on Growth and Uptake of Cd and Zn by Wetland Plants, Typha angustifolia and Colocasia esculenta from Contaminated Sediments.

    Science.gov (United States)

    Chayapan, P; Kruatrachue, M; Meetam, M; Pokethitiyook, P

    2015-01-01

    A pot study was conducted to compare the effects of amendments (CaHPO4 and cow manure) on growth and uptake of Cd and Zn from contaminated sediments by two wetland plant species, Typha angustifolia and Colocasia esculenta. Contaminated sediments (Cd 33.2 mg kg(-1) and Zn 363 mg kg(-1)) were collected from Mae Tao basin, Mae Sot district, Tak province, Thailand. The experiment consisted of 4 treatments: control (uncontaminated sediment), Cd/Zn, Cd/Zn + 5% CaHPO4, and Cd/Zn + 10% cow manure. Plants were grown for 3 months in the greenhouse. The addition of CaHPO4 resulted in the highest relative growth rate (RGR) and highest Cd accumulation in both T. angustifolia and C. esculenta while the lowest RGR was found in C. esculenta grown in the cow manure treatment. Both plant species had higher concentrations of metals (Cd, Zn) in their belowground parts. None of the amendments affected Zn accumulation. C. esculenta exhibited the highest uptake of both Cd and Zn. The results clearly demonstrated the phytoremediation potential of C. esculenta and the enhancement of this potential by CaHPO4 amendment.

  4. Effect of Fe(III) on 1,1,2,2-tetrachloroethane degradation and vinyl chloride accumulation in wetland sediments of the Aberdeen proving ground

    Science.gov (United States)

    Jones, E.J.P.; Voytek, M.A.; Lorah, M.M.

    2004-01-01

    1,1,2,2-Tetrachloroethane (TeCA) contaminated groundwater at the Aberdeen Proving Ground discharges through an anaerobic wetland in West Branch Canal Creek, MD, where dechlorination occurred. Two microbially mediated pathways, dichloroelimination and hydrogenolysis, account for most of the TeCA degradation at this site. The dichloroelimination pathways led to the formation of vinyl chloride (VC), a recalcitrant carcinogen of great concern. The effect of adding Fe(III) to TeCA-amended microcosms of wetland sediment was studied. Differences were identified in the TeCA degradation pathway between microcosms treated with amorphous ferric oxyhydroxide (AFO-treated) and untreated (no AFO) microcosms. TeCA degradation was accompanied by a lower accumulation of VC in AFO-treated microcosms than no AFO microcosms. The microcosm incubations and subsequent experiments with the microcosm materials showed that AFO treatment resulted in lower production of VC by shifting TeCA degradation from dichloroelimination pathways to production of a greater proportion of chlorinated ethane products, and decreasing the microbial capability to produce VC from 1,2-dichloroethylene. VC degradation was not stimulated in the presence of Fe(III). Rather, VC degradation occurred readily under methanogenic conditions and was inhibited under Fe(III)-reducing conditions.

  5. Sediment record of polycyclic aromatic hydrocarbons in the Liaohe River Delta wetland, Northeast China: Implications for regional population migration and economic development.

    Science.gov (United States)

    Ma, Chuanliang; Lin, Tian; Ye, Siyuan; Ding, Xigui; Li, Yuanyuan; Guo, Zhigang

    2017-03-01

    The polycyclic aromatic hydrocarbons (PAHs) of a (210)Pb-dated sediment core extracted from the Liaohe River Delta wetland were measured to reconstruct the sediment record of PAHs and its response to human activity for the past 300 years in Northeast China. The concentrations of the 16 U.S. Environmental Protection Agency priority PAHs (∑16PAHs) ranged from 46 to 1167 ng g(-1) in this sediment core. The concentrations of the 16 PAHs (especially 4- and 5+6-ring PAHs) after the 1980s (surface sediments 0-6 cm) were one or two orders of magnitudes higher than those of the down-core samples. The exponential growth of 4-ring and 5+6-ring PAH concentrations after the 1980s responded well to the increased energy consumption and number of civil vehicles resulting from the rapid economic development in China. Prior to 1950, relatively low levels of the 16 PAHs and a high proportion of 2+3-ring PAHs was indicative of biomass burning as the main source of the PAHs. A significant increase in the 2 + 3 ring PAH concentration from the 1860s-1920s was observed and could be attributed to a constant influx of population migration into Northeast China. It was suggested that the link between historical trend of PAHs and population or energy use involves two different economic stages. Typically, in an agricultural economy, the greater the population size, the greater the emission of PAHs from biomass burning, while in an industrial economy, the increase in sedimentary PAH concentrations is closely related to increasing energy consumption of fossil fuels.

  6. 多种环境因子交互作用对沉积物吸附阿特拉津的影响%Characteristics of Atrazine Adsorption onto Surficial Sediments Influenced by Interaction of Various Environmental Factors

    Institute of Scientific and Technical Information of China (English)

    李鱼; 王志增; 王檬; 王倩

    2013-01-01

    采用自行研制的模拟自然水环境吸附解吸系统实验装置,运用24完全析因实验设计,研究4种环境因子(pH、离子强度、曝气强度和温度)共同作用对沉积物吸附阿特拉津的影响规律,并利用固定效应模型估算各环境因子主效应和高阶交互效应对沉积物吸附阿特拉津的贡献.结果表明:4种环境因子主效应对沉积物吸附阿特拉津的影响均较大(显著性水平0.05),其中曝气强度与离子强度促进沉积物吸附阿特拉津,温度与pH抑制沉积物吸附阿特拉津;4种环境因子的二阶交互效应对沉积物吸附阿特拉津的影响也较大(显著性水平0.05),效应估计值依次为温度×pH值=-73.53,曝气强度×pH值=-59.03,温度×离子强度=33.19,pH值×离子强度=27.55;在三阶交互作用中,仅有曝气强度×温度×pH值可促进沉积物吸附阿特拉津(显著性水平0.05).%In order to fully reveal the migration and transformation of the pesticide atrazine in natural water bodies we studied the characteristics of atrazine adsorption on the sediments influenced by a variety of environmental factors (such as pH, ionic strength, aeration rate, and temperature) via the simulation by means of self-designed natural water environment adsorption/desorption system experimental device based on 24 full factorial experimental design, and then employed the fixed effect model to analyze the contribution from the mathematical quantitative perspective about the main effects of various environmental factors and higher-order interaction effects to adsorption of atrazine on the sediments. It was found that the main effects of the four selected environmental factors (pH, ionic strength, aeration rate, and temperature) all have a significant impact (significance level of 0. 05) to atrazine adsorption on the sediments, in which the aeration rate and the ionic strength significantly promote atrazine adsorption on sediments, while the temperature and p

  7. Restoring Wetlands

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    FERTILE LAND:The Qixing River Wetland in Heilongjiang Province was recently named a wetland of international importance at the Sixth Asian Wetland Symposium held in Wuxi City, east China’s Jiangsu Province, on October 13

  8. The effects of co-contaminants and native wetland sediments on the activity and dominant transformation mechanisms of a 1,1,2,2-tetrachloroethane (TeCA)-degrading enrichment culture

    Science.gov (United States)

    Lorah, Michelle M.; Schiffmacher, Emily N.; Becker, Jennifer G.; Voytek, Mary A.

    2016-01-01

    Bioremediation strategies, including bioaugmentation with chlorinated ethene-degrading enrichment cultures, have been successfully applied in the cleanup of subsurface environments contaminated with tetrachloroethene (PCE) and/or trichloroethene (TCE). However, these compounds are frequently found in the environment as components of mixtures that may also contain chlorinated ethanes and methanes. Under these conditions, the implementation of bioremediation may be complicated by inhibition effects, particularly when multiple dehalorespirers are present. We investigated the ability of the 1,1,2,2-tetrachloroethane (TeCA)-dechlorinating culture WBC-2 to biotransform TeCA alone, or a mixture of TeCA plus PCE and carbon tetrachloride (CT), in microcosms. The microcosms contained electron donors provided to biostimulate the added culture and sediment collected from a wetland where numerous “hotspots” of contamination with chlorinated solvent mixtures exist. The dominant TeCA biodegradation mechanism mediated by the WBC-2 culture in the microcosms was different in the presence of these wetland sediments than in the sediment-free enrichment culture or in previous WBC-2 bioaugmented microcosms and column tests conducted with wetland sediment collected at nearby sites. The co-contaminants and their daughter products also inhibited TeCA biodegradation by WBC-2. These results highlight the need to conduct biodegradability assays at new sites, particularly when multiple contaminants and dehalorespiring populations are present.

  9. Complex community of nitrite-dependent anaerobic methane oxidation bacteria in coastal sediments of the Mai Po wetland by PCR amplification of both 16S rRNA and pmoA genes.

    Science.gov (United States)

    Chen, Jing; Zhou, Zhichao; Gu, Ji-Dong

    2015-02-01

    In the present work, both 16S rRNA and pmoA gene-based PCR primers were employed successfully to study the diversity and distribution of n-damo bacteria in the surface and lower layer sediments at the coastal Mai Po wetland. The occurrence of n-damo bacteria in both the surface and subsurface sediments with high diversity was confirmed in this study. Unlike the two other known n-damo communities from coastal areas, the pmoA gene-amplified sequences in the present work clustered not only with some freshwater subclusters but also within three newly erected marine subclusters mostly, indicating the unique niche specificity of n-damo bacteria in this wetland. Results suggested vegetation affected the distribution and community structures of n-damo bacteria in the sediments and n-damo could coexist with sulfate-reducing methanotrophs in the coastal ecosystem. Community structures of the Mai Po n-damo bacteria based on 16S rRNA gene were different from those of either the freshwater or the marine. In contrast, structures of the Mai Po n-damo communities based on pmoA gene grouped with the marine ones and were clearly distinguished from the freshwater ones. The abundance of n-damo bacteria at this wetland was quantified using 16S rRNA gene PCR primers to be 2.65-6.71 × 10(5) copies/g dry sediment. Ammonium and nitrite strongly affected the community structures and distribution of n-damo bacteria in the coastal Mai Po wetland sediments.

  10. A report on the trace element concentrations in sediments, vegetation, and fishes from the Lake Thompson Wetland Complex, South Dakota

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The results of this study identify the contaminants present, if any, and their concentrations in fish, cattail roots, and sediments from areas of concern in the Lake...

  11. Constructed Wetlands

    Science.gov (United States)

    these systems can improve water quality, engineers and scientists construct systems that replicate the functions of natural wetlands. Constructed wetlands are treatment systems that use natural processes

  12. Spatial distribution of phosphorus speciation in marsh sediments along a hydrologic gradient in a subtropical estuarine wetland, China

    Science.gov (United States)

    Zhang, Wen-Long; Zeng, Cong-Sheng; Tong, Chuan; Zhai, Shui-Jing; Lin, Xiao; Gao, Deng-Zhou

    2015-03-01

    In May and August 2013, a 360-m long transect (from a high to a middle tidal flat) was laid out in the Min River estuarine marsh to study the distribution of total phosphorus (TP) and its fractions (i.e., organic P (Org P), inorganic P (IP), aluminum-bound P (Al-P), iron-bound P (Fe-P), occluded P (O-P), and calcium-bound P (Ca-P)). The results showed that TP concentrations of the sediments ranged from 338 to 846 mg kg-1 (average 664 mg kg-1) in May and from 353 to 932 mg kg-1 (average 657 mg kg-1) in August. IP dominated the P fractions (accounting for 57-81% of TP) and was mainly composed of Fe-P (38%), O-P (30%), and Ca-P (25%). The TP, IP and Fe-P concentrations fluctuated along the hydrologic gradient during both measurement periods (except for the upper 10-cm sediments in August). Meanwhile, their concentrations decreased with depth (0-50 cm), but vertical variation declined in the middle tidal flat. A higher concentration of Org P was observed in the upper 20-cm sediments of the high tidal flat. The concentrations of Ca-P and Al-P increased from the high tidal flat to the middle tidal flat, but there was no significant difference between sediment layers (P > 0.05). The O-P concentration was significantly higher in Phragmites australis sediments compared with Cyperus malaccensis sediments (P < 0.05). Based on the space-for-time substitution rule, we predict that sea-level change will likely alter the composition and vertical distribution of TP in the Min River estuarine sediments.

  13. Temporal and spatial distributions of sediment mercury at salt pond wetland restoration sites, San Francisco Bay, CA, USA

    Science.gov (United States)

    Miles, A.K.; Ricca, M.A.

    2010-01-01

    Decommissioned agricultural salt ponds within south San Francisco Bay, California, are in the process of being converted to habitat for the benefit of wildlife as well as water management needs and recreation. Little is known of baseline levels of contaminants in these ponds, particularly mercury (Hg), which has a well established legacy in the Bay. In this study we described spatial and short-term temporal variations in sediment Hg species concentrations within and among the Alviso and Eden Landing salt ponds in the southern region of San Francisco Bay. We determined total Hg (Hgt) and methylmercury (MeHg) in the top 5 cm of sediment of most ponds in order to establish baseline conditions prior to restoration, sediment Hgt concentrations in a subset of these ponds after commencement of restoration, and variation in MeHg concentrations relative to sediment Hgt, pH, and total Fe concentrations and water depth and salinity in the subset of Alviso ponds. Inter-pond differences were greatest within the Alviso pond complex, where sediment Hgt concentrations averaged (arithmetic mean) 0.74 ??g/g pre and 1.03 ??g/g post-restoration activity compared to 0.11 ??g/g pre and post at Eden Landing ponds. Sediment Hgt levels at Alviso were fairly stable temporally and spatially, whereas MeHg levels were variable relative to restoration activities across time and space. Mean (arithmetic) sediment MeHg concentrations increased (2.58 to 3.03 ng/g) in Alviso and decreased (2.20 to 1.03 ng/g) in Eden Landing restoration ponds during the study. Differences in MeHg levels were related to water depth and pH, but these relationships were not consistent between years or among ponds and were viewed with caution. Factors affecting MeHg levels in these ponds (and in general) are highly complex and require in-depth study to understand.

  14. National Wetlands Inventory - Wetlands

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This data set represents the extent, approximate location and type of wetlands and deepwater habitats in the United States and its Territories. These data delineate...

  15. National Wetlands Inventory - Wetlands

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This data set represents the extent, approximate location and type of wetlands and deepwater habitats in the United States and its Territories. These data delineate...

  16. Wetlands sediment record from the upper Yarlung Tsangpo valley, southwest Tibetan Plateau, reveals mid-Holocene Epipaleolithic human occupation coincident with increased early and mid-Holocene wetness driven by enhanced Indian Monsoon rainfall

    Science.gov (United States)

    Hudson, A. M.; Olsen, J. W.; Quade, J.; Lei, G.; Huth, T.; Zhang, H.; Perreault, C.

    2016-12-01

    The headwaters of the Yarlung Tsangpo river valley, located in the southwestern Tibetan Plateau, are characterized by a cold and dry climate, but contain abundant river-marginal wetlands environments, which fluctuate in extent in response to changes in local water table elevation. This region receives 80% of precipitation from the Indian Monsoon, which forms the dominant control on moisture availability, and hence wetlands extent. Our paleowetlands record, based on 14C dating of organic-rich paleowetlands deposits, provides a novel record of Holocene monsoon intensity. The wetlands deposits consist of four sedimentary units that indicate decreasing wetlands extent and monsoon intensity since 10.4 ka BP. Wet conditions occurred at ˜10.4 ka BP, ˜9.6 ka BP and ˜7.9-4.8 ka BP, with similar-to-modern conditions from ˜4.6-2.0 ka BP, and drier-than-modern conditions from ˜2.0 ka BP to present. Wetland changes correlate with monsoon intensity changes identified in nearby records, with weak monsoon intervals corresponding to desiccation and erosion of wetlands deposits. Dating of in situ ceramic and microlithic artifacts in wetlands sediments at multiple sites indicates Epipaleolithic human occupation of the YT valley after 6.6 ka BP. Artifact typology study reveals a similar microlithic technology was employed across the high plateau interior, but XRF obsidian provenance reveals separate northeast and southwest lithic conveyance zones. This indicates widespread colonization of the high, arid Tibetan Plateau interior by one or more highly mobile human populations during the early and mid-Holocene, coincident with favorable warm, wet climate conditions.

  17. Evaluating the potential effects of hurricanes on long-term sediment accumulation in two micro-tidal sub-estuaries: Barnegat Bay and Little Egg Harbor, New Jersey, U.S.A.

    Science.gov (United States)

    Marot, Marci E.; Smith, Christopher G.; Ellis, Alisha M.; Wheaton, Cathryn J.

    2016-06-23

    Barnegat Bay, located along the eastern shore of New Jersey, was significantly impacted by Hurricane Sandy in October 2012. Scientists from the U.S. Geological Survey (USGS) developed a multidisciplinary study of sediment transport and hydrodynamics to understand the mechanisms that govern estuarine and wetland responses to storm forcing. This report details the physical and chemical characteristics of surficial and downcore sediments from two areas within the bay. Eleven sites were sampled in both the central portion of the bay near Barnegat Inlet and in the southern portion of the bay in Little Egg Harbor. Laboratory analyses include Be-7, Pb-210, bulk density, porosity, x-radiographs, and grain-size distribution. These data will serve as a critical baseline dataset for understanding the current sedimentological regime and can be applied to future storms for understanding estuarine and wetland evolution.

  18. Trace element concentrations in sediment and biota from the Benton Lake Wetland Management District, north-central Montana

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This study was conducted to determine if trace elements are accumulating in either sediment or the aquatic food chain of water-bird habitats within the U.S. Fish and...

  19. Wetland development, permafrost history and nutrient cycling inferred from late Holocene peat and lake sediment records in subarctic Sweden

    DEFF Research Database (Denmark)

    Kokfelt, U.; Reuss, N.; Struyf, E.

    2010-01-01

    dynamics. Peat inception took place at ca. 4,700 cal BP as a result of terrestrialisation. Onset of organic sedimentation in the adjacent lakes occurred at ca. 3,400 and 2,650 cal BP in response to mire expansion and permafrost aggradation, respectively. Mire erosion, possibly due to permafrost decay, led...

  20. Microbiology of wetlands

    NARCIS (Netherlands)

    Bodelier, P.L.E.; Dedysh, S.N.

    2013-01-01

    Watersaturated soil and sediment ecosystems (i.e. wetlands) are ecologically as well as economically important systems due to their high productivity, their nutrient (re)cycling capacities and their prominent contribution to global greenhouse gas emissions. Being on the transition between terrestria

  1. Microbiology of wetlands

    NARCIS (Netherlands)

    Bodelier, P.L.E.; Dedysh, S.N.

    2013-01-01

    Watersaturated soil and sediment ecosystems (i.e. wetlands) are ecologically as well as economically important systems due to their high productivity, their nutrient (re)cycling capacities and their prominent contribution to global greenhouse gas emissions. Being on the transition between

  2. Wetland Paleoecological Study of Coastal Louisiana: X-radiographs

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Wetland sediment data was collected from coastal Louisiana as part of a pilot study to develop a diatom-based proxy for past wetland water chemistry and the...

  3. Future vegetation patterns and primary production in the coastal wetlands of East China under sea level rise, sediment reduction, and saltwater intrusion

    Science.gov (United States)

    Ge, Zhen-Ming; Cao, Hao-Bin; Cui, Li-Fang; Zhao, Bin; Zhang, Li-Quan

    2015-10-01

    To explore the effects of sea level rise (SLR), sediment reduction (SR), and saltwater intrusion (SWI) on the vegetation patterns and primary production of one exotic (Spartina alterniflora) and two native dominant (Scirpus mariqueter and Phragmites australis) species in the coastal wetlands of East China, range expansion monitoring and stress experiments were conducted, followed by model prediction. After a rapid invasion period, the expansion rate of S. alterniflora slowed down due to the decreasing availability of suitable habitat under prolonged inundation. SLR was shown to decrease the colonization of S. alterniflora and the native P. australis up to 2100. In contrast, the native S. mariqueter that has a high tolerance of inundation increased in area following SLR, due to a reduction in competition from S. alterniflora in low-lying habitats and even recolonized areas previously invaded by the exotic species. The combination of SLR and SR resulted in further degradation of S. alterniflora and P. australis, while the area of S. mariqueter was not reduced significantly. The decrease in the area of vegetation would reduce the gross primary production under SLR and SR. SWI exacerbates the impacts, especially for P. australis, because S. alterniflora and S. mariqueter have a higher tolerance of salinity. Thus, the coastal vegetation pattern was predicted to be modified due to species-specific adaption to changed geophysical features. This study indicated that the native species better adapted to prolonged inundation and increased salinity might once again become key contributors to primary production on the muddy coasts of East China.

  4. Surficial geologic map of the Ivanpah 30' x 60' quadrangle, San Bernardino County, California, and Clark County, Nevada

    Science.gov (United States)

    Miller, David M.

    2012-01-01

    This map was prepared as part of a suite of surficial geologic maps covering the northern Mojave Desert to investigate neotectonic features and map soils of relevance for ecological properties. The map covers an area of the eastern Mojave Desert that includes the Cinder Cones, Cima Dome, Ivanpah Valley, and Lanfair Valley and includes major mountain chains of the Providence, New York, and Ivanpah Mountains, all within the Mojave National Preserve. Surficial geology includes expansive pediments, broad valley-bottom sediment tracts, and dune fields of the Devils Playground. Two Quaternary fault zones are identified, as well as several others that probably are Quaternary.

  5. Fisheries Sediment Data (WIGLEY65 shapefile)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This is a part of the National Geophysical Data Center (NGDC) Seafloor Surficial Sediment (Deck 41) Data File. Deck 41 is an original data file created by the Marine...

  6. Radioiodine concentrated in a wetland.

    Science.gov (United States)

    Kaplan, Daniel I; Zhang, Saijin; Roberts, Kimberly A; Schwehr, Kathy; Xu, Chen; Creeley, Danielle; Ho, Yi-Fang; Li, Hsiu-Ping; Yeager, Chris M; Santschi, Peter H

    2014-05-01

    Most subsurface environmental radioactivity contamination is expected to eventually resurface in riparian zones, or wetlands. There are a number of extremely sharp biogeochemical interfaces in wetlands that could alter radionuclide speciation and promote accumulation. The objective of this study was to determine if a wetland concentrated (129)I emanating from a former waste disposal basin located on the Savannah River Site (SRS) in South Carolina, USA. Additionally, studies were conducted to evaluate the role of sediment organic matter in immobilizing the radioiodine. Groundwater samples were collected along a 0.7-km transect away from the seepage basin and in the downstream wetlands. The samples were analyzed for (129)I speciation (iodide (I(-)), iodate (IO3(-)), and organo-I). Groundwater (129)I concentrations in many locations in the wetlands (as high as 59.9 Bq L(-1)(129)I) were greatly elevated with respect to the source term (5.9 Bq L(-1)(129)I). (129)I concentration profiles in sediment cores were closely correlated to organic matter concentrations (r(2) = 0.992; n = 5). While the sediment organic matter promoted the uptake of (129)I to the wetland sediment, it also promoted the formation of a soluble organic fraction: 74% of the wetland groundwater (129)I could pass through a 1 kDa (wetlands may be highly effective at immobilizing aqueous (129)I, they may also promote the formation of a low-molecular-weight organic species that does not partition to sediments. This study provides a rare example of radioactivity concentrations increasing rather than decreasing as it migrates from a point source and brings into question assumptions in risk models regarding continuous dilution of released contaminants.

  7. Levels and chemical speciation of arsenic in representative biota and sediments of a tropical mangrove wetland, India.

    Science.gov (United States)

    Fattorini, Daniele; Sarkar, Santosh Kumar; Regoli, Francesco; Bhattacharya, Bhaskar Deb; Rakshit, Dibyendu; Satpathy, Kamala Kanta; Chatterjee, Mousumi

    2013-04-01

    The general concern for arsenic in the marine environment is associated with its wide distribution and potential toxicity. In the present work, concentrations and chemical speciation of arsenic were characterized in sediments and representative biota from the Indian Sundarban, the largest continuous mangrove tract formed at the mouth of the Hugli (Ganges) River estuary, northeastern part of the Bay of Bengal. Analyzed organisms included both shellfish (Macoma birmanica, Sanguinolaria acuminata and Meretrix meretrix) and finfish (Liza parsia, Liza tade, Harpodon nehereus and Eleutheronema tetradactylum). Arsenic concentrations in sediments did not exceed 4 μg g(-1) dry weight with the contribution of inorganic molecules (arsenate and arsenite) ranging from 61.7 to 81.3%. Total As (TAs) concentrations varied from less than 2 to 16 μg g(-1) in tissues of bivalves; the more elevated As accumulation was observed in gills and the mantle probably due to ion exchange properties of the mucous layer covering these organs, whereas adductor muscle and the podium showed limited values. Distribution of various arsenic compounds followed a quite similar trend in bivalve tissues; arsenobetaine (AsB) was the most dominant form followed by compounds such as dimethylarsinate (DMA), trimethyl arsine-oxide (TMAO), tetramethyl arsonium (TETRA) and arsenocholine (AsC), while inorganic arsenic (IAs) represented a minor constituent (0.2 to 6.9%). Among the fish, detritivorous/herbivorous species (L. parsia and L. tade) exhibited TAs concentrations of 10.8 and 9.71 μg g(-1) dry wt with a prevalence of AsB (52-67%) and TETRA (26-35%); higher concentrations of TAs were measured in the two carnivorous species (20.62 and 19.67 μg g(-1) dry wt, in H. nehereus and E. tetradactylum respectively) mostly as AsB (63.3-72.3%) and AsC (17.5-28.6%). The obtained results can be considered as baseline levels for arsenic in the investigated area, confirming the predominance of organoarsenicals in

  8. Spreading of sediment due to underwater blasting and dredging

    DEFF Research Database (Denmark)

    Nielsen, Morten Holtegaard; Bach, Lis; Bollwerk, Sandra

    2015-01-01

    leads to a wider spreading of the organic part of the sediment. Almost all material less than 2 μm, including surficial clay minerals and much organic material, was transported away from the construction site and its vicinity, which could imply mobilization and export of pollutants. Environmental...... or maybe even increasing the spreading of sediment, depending on, e.g., the resilience of the flora and fauna and the surficial sediment and the pollution therein....

  9. Ecohydraulics and Estuarine Wetland Rehabilitation

    Science.gov (United States)

    Rodriguez, J. F.; Howe, A.; Saintilan, N.; Spencer, J.

    2004-12-01

    The hydraulics or water flow in wetlands is known to be a key factor influencing ecosystem development in estuarine wetland environments. The relationship is indirect, with the hydraulics of wetlands influencing a host of factors including soil salinity, waterlogging, sediment transport, sediment chemistry, vegetation dispersal and growth and nutrient availability and cycling. The relationship is also not one way, with the hydraulics of wetlands being influenced by plant and animal activity. Understanding these complex interactions is fundamental for the adequate management of estuarine wetlands. Listed as a Wetland of International Importance under the 1971 Ramsar Convention, the Hunter River estuary is regarded as the most significant site for migratory shorebirds in New South Wales, Australia. Over the past 20 years, the number of migratory shorebirds in the estuary has sharply declined from 8,000 to 4,000 approx. Alteration of bird habitat is believed to be one of the reasons for this alarming trend. In 2004 we started a three-year program to investigate the links between hydraulics, sediment, benthic invertebrates, vegetation and migratory shorebird habitat in the estuary. During the first year we have focused on a highly disturbed part of the Hunter estuary wetlands located on Ash Island. The area is one of the major roosting sites in the estuary and is characterized by a complex hydraulic regime due to a restricted tidal interchange with the Hunter River and the presence of infrastructure for the maintenance of power lines (i.e., roads, bridges, culverts). Salt marshes, mudflat and mangroves are the dominant vegetation types. The monitoring program includes measurements of water levels, salinity, discharge, velocity, turbulence, sediment transport and deposition, plant species and density, soil composition and benthic invertebrates coordinated with observations of bird habitat utilization on a number of locations throughout the wetland and for different flow

  10. The surficial aquifer in Pinellas County, Florida

    Science.gov (United States)

    Causseaux, K.W.

    1985-01-01

    The surficial aquifer in Pinellas County, Florida, contains potable water throughout most of the county and is a potential source of water to augment the public supply that is presently imported from adjacent counties. The county accounts for 38 percent of the public supply consumption of ground water in the 11-county area of west-central Florida and 68 percent of this water is imported from two adjacent counties. The surficial aquifer has a saturated thickness of more than 30 feet throughout most of the county. Specific capacity per foot of screen for wells is less than 0.1 gallon per minute per foot of drawdown in some parts of the county, but yield is sufficient in most of the county for many small uses with shallow-well pumps. Minimum potential yield varies from 5 gallons per minute in the northern part of the county to more than 30 gallons per minute in the south. Concentrations of iron are high enough in parts of the county to cause staining. Chloride concentrations are less than 100 milligrams per liter in most of the county and do not pose a problem for many uses. (USGS)

  11. Integrated Modeling of Groundwater and Surface Water Interactions in a Manmade Wetland

    Directory of Open Access Journals (Sweden)

    Guobiao Huang Gour-Tsyh Yeh

    2012-01-01

    Full Text Available A manmade pilot wetland in south Florida, the Everglades Nutrient Removal (ENR project, was modeled with a physics-based integrated approach using WASH123D (Yeh et al. 2006. Storm water is routed into the treatment wetland for phosphorus removal by plant and sediment uptake. It overlies a highly permeable surficial groundwater aquifer. Strong surface water and groundwater interactions are a key component of the hydrologic processes. The site has extensive field measurement and monitoring tools that provide point scale and distributed data on surface water levels, groundwater levels, and the physical range of hydraulic parameters and hydrologic fluxes. Previous hydrologic and hydrodynamic modeling studies have treated seepage losses empirically by some simple regression equations and, only surface water flows are modeled in detail. Several years of operational data are available and were used in model historical matching and validation. The validity of a diffusion wave approximation for two-dimensional overland flow (in the region with very flat topography was also tested. The uniqueness of this modeling study is notable for (1 the point scale and distributed comparison of model results with observed data; (2 model parameters based on available field test data; and (3 water flows in the study area include two-dimensional overland flow, hydraulic structures/levees, three-dimensional subsurface flow and one-dimensional canal flow and their interactions. This study demonstrates the need and the utility of a physics-based modeling approach for strong surface water and groundwater interactions.

  12. Marine sediments and palaeoclimatic variations since the Late Pleistocene: An overview for the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.; Hashimi, N.H.

    A large number of surfacial and sub-surface sediments from the Arabian Sea have been studied to enhance our understanding of palaeoclimatic variations over the Indian region. Bsically the surficial sediments have been studied for their living...

  13. Influence of an aerobic sediment-water interface in relation to reduced risk of phosphorus leaching from re-established wetlands

    DEFF Research Database (Denmark)

    Forsmann, Ditte M.; Kjærgaard, Charlotte

    Re-establishing of wetlands on former drained lowland areas used for agriculture has come into focus as a measure to reduce nutrient losses to the aquatic environment. However, new results have documented significant accumulations of iron bound phosphorus in Danish lowland soils (Kjaergaard et al......., 2007). Thus, re-establishment of wetlands might constitute a risk of excess phosphorus loss to the aquatic environment, as changes in redox conditions may lead to reductive dissolution of iron(III) oxides and consequently release of iron bound phosphorus (Hoffmann et al., 2009). Groundwater and surface...... water interactions are of fundamental importance for the biogeochemical processes controlling phosphorus dynamics in wetlands, and different hydrological pathways such as groundwater discharge and surface water flooding are operating within wetlands (Hoffmann et al., 2009). During groundwater discharge...

  14. Mercury Removal, Methylmercury Formation, and Sulfate-Reducing Bacteria Profiles in Wetland Mesocosms Containing Gypsum-Amended Sediments and Scirpus californicus

    Energy Technology Data Exchange (ETDEWEB)

    King, J.K.

    2001-03-02

    A pilot-scale model was constructed to determine if a wetland treatment system (WTS) could effectively remove low-level mercury from an outfall located at the Department of Energy's Savannah River Site.

  15. A significant nexus: Geographically isolated wetlands influence landscape hydrology

    Science.gov (United States)

    McLaughlin, Daniel L.; Kaplan, David A.; Cohen, Matthew J.

    2014-09-01

    Recent U.S. Supreme Court rulings have limited federal protections for geographically isolated wetlands (GIWs) except where a "significant nexus" to a navigable water body is demonstrated. Geographic isolation does not imply GIWs are hydrologically disconnected; indeed, wetland-groundwater interactions may yield important controls on regional hydrology. Differences in specific yield (Sy) between uplands and inundated GIWs drive differences in water level responses to precipitation and evapotranspiration, leading to frequent reversals in hydraulic gradients that cause GIWs to act as both groundwater sinks and sources. These reversals are predicted to buffer surficial aquifer dynamics and thus base flow delivery, a process we refer to as landscape hydrologic capacitance. To test this hypothesis, we connected models of soil moisture, upland water table, and wetland stage to simulate hydrology of a low-relief landscape with GIWs, and explored the influences of total wetland area, individual wetland size, climate, and soil texture on water table and base flow variation. Increasing total wetland area and decreasing individual wetland size substantially decreased water table and base flow variation (e.g., reducing base flow standard deviation by as much as 50%). GIWs also decreased the frequency of extremely high and low water tables and base flow deliveries. For the same total wetland area, landscapes with fewer (i.e., larger) wetlands exhibited markedly lower hydrologic capacitance than those with more (i.e., smaller) wetlands, highlighting the importance of small GIWs to regional hydrology. Our results suggest that GIWs buffer dynamics of the surficial aquifer and stream base flow, providing an indirect but significant nexus to the regional hydrologic system.

  16. Influence of an aerobic sediment-water interface in relation to reduced risk of phosphorus leaching from re-established wetlands

    OpenAIRE

    Forsmann, Ditte M.; Kjærgaard, Charlotte

    2011-01-01

    Re-establishing of wetlands on former drained lowland areas used for agriculture has come into focus as a measure to reduce nutrient losses to the aquatic environment. However, new results have documented significant accumulations of iron bound phosphorus in Danish lowland soils (Kjaergaard et al., 2007). Thus, re-establishment of wetlands might constitute a risk of excess phosphorus loss to the aquatic environment, as changes in redox conditions may lead to reductive dissolution of iron(III)...

  17. Chemical Properties of Pore Water and Sediment at Three Wetland Sites Near the F- and H-Area Seepage Basins, Savannah River Site

    Energy Technology Data Exchange (ETDEWEB)

    Friday, G.P.

    2001-05-15

    In 1980, vegetative stress and arboreal mortality in wetland plant communities down-gradient from the F- and H-Area seepage basins were detected using aerial imagery. By 1988, approximately six acres in H-Area and four acres in F-Area had been adversely impacted. Today, wetland plant communities have become well established at the H-Area tree-kill zone.

  18. Surficial geological tools in fluvial geomorphology

    Science.gov (United States)

    Jacobson, Robert B.; O'connor, James; Oguchi, Takashi

    2016-01-01

    Environmental scientists are increasingly asked how rivers and streams have been altered by past environmental stresses, whether rivers are subject to physical or chemical hazards, how they can be restored and how they will respond to future environmental changes. These questions present substantive challenges to the discipline of fluvial geomorphology as they require a long-term understanding of river-system dynamics. Complex and non-linear responses of rivers to environmental stresses indicate that synoptic or short-term historical views of rivers will often give an incomplete understanding. Fluvial geomorphologists can address questions involving complex river behaviours by drawing from a tool box that includes the principles and methods of geology applied to the surficial geological record. A central concept in Earth Sciences holds that ‘the present is the key to the past’ (Hutton 1788, cited in Chorley et al. 1964), that is, understanding of current processes permits the interpretation of past deposits. Similarly, an understanding of the past can be key to predicting the future. A river’s depositional history can be indicative of trends or episodic behaviours that can be attributed to particular environmental stresses or forcings. Its history may indicate the role of low-frequency events such as floods or landslides in structuring a river and its floodplain or a river’s depositional history can provide an understanding of its natural characteristics to serve as a reference condition for assessments and restoration. However, the surficial geological record contained in river deposits is incomplete and biased and it presents numerous challenges of interpretation. The stratigraphic record in general has been characterized as ‘ … a lot of holes tied together with sediment’ (Ager 1993). Yet this record is critical in the development of integrated understanding of fluvial geomorphology because it provides information that is not available from other

  19. Climate Change and Intertidal Wetlands

    Directory of Open Access Journals (Sweden)

    Pauline M. Ross

    2013-03-01

    Full Text Available Intertidal wetlands are recognised for the provision of a range of valued ecosystem services. The two major categories of intertidal wetlands discussed in this contribution are saltmarshes and mangrove forests. Intertidal wetlands are under threat from a range of anthropogenic causes, some site-specific, others acting globally. Globally acting factors include climate change and its driving cause—the increasing atmospheric concentrations of greenhouse gases. One direct consequence of climate change will be global sea level rise due to thermal expansion of the oceans, and, in the longer term, the melting of ice caps and glaciers. The relative sea level rise experienced at any one locality will be affected by a range of factors, as will the response of intertidal wetlands to the change in sea level. If relative sea level is rising and sedimentation within intertidal wetlands does not keep pace, then there will be loss of intertidal wetlands from the seaward edge, with survival of the ecosystems only possible if they can retreat inland. When retreat is not possible, the wetland area will decline in response to the “squeeze” experienced. Any changes to intertidal wetland vegetation, as a consequence of climate change, will have flow on effects to biota, while changes to biota will affect intertidal vegetation. Wetland biota may respond to climate change by shifting in distribution and abundance landward, evolving or becoming extinct. In addition, impacts from ocean acidification and warming are predicted to affect the fertilisation, larval development, growth and survival of intertidal wetland biota including macroinvertebrates, such as molluscs and crabs, and vertebrates such as fish and potentially birds. The capacity of organisms to move and adapt will depend on their life history characteristics, phenotypic plasticity, genetic variability, inheritability of adaptive characteristics, and the predicted rates of environmental change.

  20. Climate change and intertidal wetlands.

    Science.gov (United States)

    Ross, Pauline M; Adam, Paul

    2013-03-19

    Intertidal wetlands are recognised for the provision of a range of valued ecosystem services. The two major categories of intertidal wetlands discussed in this contribution are saltmarshes and mangrove forests. Intertidal wetlands are under threat from a range of anthropogenic causes, some site-specific, others acting globally. Globally acting factors include climate change and its driving cause-the increasing atmospheric concentrations of greenhouse gases. One direct consequence of climate change will be global sea level rise due to thermal expansion of the oceans, and, in the longer term, the melting of ice caps and glaciers. The relative sea level rise experienced at any one locality will be affected by a range of factors, as will the response of intertidal wetlands to the change in sea level. If relative sea level is rising and sedimentation within intertidal wetlands does not keep pace, then there will be loss of intertidal wetlands from the seaward edge, with survival of the ecosystems only possible if they can retreat inland. When retreat is not possible, the wetland area will decline in response to the "squeeze" experienced. Any changes to intertidal wetland vegetation, as a consequence of climate change, will have flow on effects to biota, while changes to biota will affect intertidal vegetation. Wetland biota may respond to climate change by shifting in distribution and abundance landward, evolving or becoming extinct. In addition, impacts from ocean acidification and warming are predicted to affect the fertilisation, larval development, growth and survival of intertidal wetland biota including macroinvertebrates, such as molluscs and crabs, and vertebrates such as fish and potentially birds. The capacity of organisms to move and adapt will depend on their life history characteristics, phenotypic plasticity, genetic variability, inheritability of adaptive characteristics, and the predicted rates of environmental change.

  1. Wetland Loss.

    Science.gov (United States)

    Barrett, Marilyn

    1994-01-01

    Examines what wetland conservation means to different groups of Louisiana's coastal residents. Describes coastal resources, reasons for their deterioration, conservation efforts, and the impact of a public perception that conservation of wetlands is closely tied to conservation of the existing lifestyle. (LZ)

  2. Wetland Hydrology

    Science.gov (United States)

    This chapter discusses the state of the science in wetland hydrology by touching upon the major hydraulic and hydrologic processes in these complex ecosystems, their measurement/estimation techniques, and modeling methods. It starts with the definition of wetlands, their benefit...

  3. Freshwater Wetlands.

    Science.gov (United States)

    Naturescope, 1986

    1986-01-01

    Provides descriptions about freshwater wetlands, such as marshes, swamps, and bogs. Contains three learning activities which deal with unusual wetland plants, the animals and plants in a typical marsh, and the effects of a draught on a swamp. Included are reproducible handouts and worksheets for two of the activities. (TW)

  4. Effects of Surfactant Adsorption on Surficial Wettability of Nonwoven Fabrics

    Institute of Scientific and Technical Information of China (English)

    CAI Bing; TANG Bing; LI Rui-xia; WU Da-cheng

    2002-01-01

    All types of surfactants (cationic, anionic and nonionic)reported in this paper could enhance the surficiai wettability of polypropylene (PP) and polyethylene terephthalate (PET) nonwoven fabrics. However, the effects of cationic and nonionic surfactants were better.The longer the treatment time of surfactants on the nonwoven fabrics, the better the surficial wettability.The surficial rewetting time would no longer change above a certain treatment time. The rewettability of nonwoven fabrics could be evidently improved just when the concentration of surfactants was just above the CMC,except for sodium dodecylbenzene sulfonate (LAS). The finer the fibers and the looser the structures, the better the surficial rewettability of nonwoven fabrics.

  5. Mercury distribution and speciation in the sediments of mangrove wetland in Quanzhou Bay%泉州湾红树林湿地沉积物中汞分布及形态特征

    Institute of Scientific and Technical Information of China (English)

    于瑞莲; 胡恭任; 刘越; 杨翼

    2011-01-01

    采集了泉州湾红树林湿地表层沉积物样品,测定了沉积物中不同形态汞的含量,研究了汞的分布特征、赋存形态及其生物有效性.泉州湾红树林湿地表层沉积物中总汞含量范围0.03~0.22 mg·kg-1,除14#采样点外,其余各采样点均符合海洋沉积物质量(GB 18668-2002) Ⅰ类标准;沉积物中不同形态汞占总汞的比例为可氧化态(84.0%)>残渣态(14.0%)>可还原态(1.8%)>弱酸溶态(0.2%);沉积物中汞的生物有效性较高,对红树林生态系统存在一定的潜在危害.%Surface sediments were sampled from the mangrove wetland in Quanzhou Bay to study the distribution, speciation, and bio-availability of mercury in the sediments. The total mercury content in the sediments ranged in 0. 03-0. 22 mg · kg-1, which met the first class standard of Marine Sediment Quality ( GB 18668-2002) , with the exception of that at site 14. The average proportion of different speciation mercury to total mercury in the sediments presented a sequence of oxidizable ( 84. 0% ) > residual ( 14. 0% ) > reducible ( 1. 8% ) > weak acid soluble ( 0. 2% ) . The relatively high bio-availability of mercury in the sediments indicated certain potential hazard to the mangrove ecosystem.

  6. Evidence of regional subsidence and associated interior wetland loss induced by hydrocarbon production, Gulf Coast region, USA

    Science.gov (United States)

    Morton, Robert A.; Bernier, Julie C.; Barras, John A.

    2006-05-01

    Analysis of remote images, elevation surveys, stratigraphic cross-sections, and hydrocarbon production data demonstrates that extensive areas of wetland loss in the northern Gulf Coast region of the United States were associated with large-volume fluid production from mature petroleum fields. Interior wetland losses at many sites in coastal Louisiana and Texas are attributed largely to accelerated land subsidence and fault reactivation induced by decreased reservoir pressures as a result of rapid or prolonged extraction of gas, oil, and associated brines. Evidence that moderately-deep hydrocarbon production has induced land-surface subsidence and reactivated faults that intersect the surface include: (1) close temporal and spatial correlation of fluid production with surficial changes including rapid subsidence of wetland sediments near producing fields, (2) measurable offsets of shallow strata across the zones of wetland loss, (3) large reductions in subsurface pressures where subsidence rates are high, (4) coincidence of orientation and direction of displacement between surface fault traces and faults that bound the reservoirs, and (5) accelerated subsidence rates near producing fields compared to subsidence rates in surrounding areas or compared to geological rates of subsidence. Based on historical trends, subsidence rates in the Gulf Coast region near producing fields most likely will decrease in the future because most petroleum fields are nearly depleted. Alternatively, continued extraction of conventional energy resources as well as potential production of alternative energy resources (geopressured-geothermal fluids) in the Gulf Coast region could increase subsidence and land losses and also contribute to inundation of areas of higher elevation.

  7. Phosphorus Forms and Its Spatial Distribution Characteristics in Surface Sediments of Zhalong Wetland%扎龙湿地表层沉积物磷的赋存形态及空间分布特征

    Institute of Scientific and Technical Information of China (English)

    叶华香; 臧淑英; 贾晓丹; 苏丹

    2012-01-01

    Different phosphorus forms have different geochemical behavior and bioavailability. Their contents and distributions contain much environmental geochemistry informatioa In this paper,total phosphorus (TP) ,organic phosphorus (OP) ,and different forms of inorganic phosphorus (IP) were analyzed by using the SMT (standards,measurements and testing harmonized protocol) method in the surface sediments of Zhalong Wetland. The spatial distribution characteristics of phosphorus forms in the surface sediments and its controlling factors were discussed. The results indicated that the contents of TP coincided with the heavy nutrition of Taihu and Chaohu Its spatial distribution lied in the core and northeast of Zhalong Wetland. TP contained IP and OP,and the content of IP was a little more than OP. In addition, their distributions were similar with the distribution of TP. The phosphorus associated with calcium (Ca-P) was the major part of IP, which was about 59. 2% of IP. Owing to high content of Ca in the north geology environmental background, the change of Ca-P spatial distribution was less than others. The grain size,organic matter,pH,dissolved oxygen (DO),etc. ,were the main controlling factors of phosphorus in sediments. From current data,it was shown that the pollutants which caused water eutrophication of Zhalong Wetland were mainly from outside. However,with the invasion of pollutants,the deterioration of ecology,and the decreasing of vegetation coverage,the P released by the sediments could be the major sources to cause water entrophication of Zhalong Wetland,especially for its core area. This research not only provides a theoretical evidence for forecasting the trophic status of the water in Zhalong Wetland,but also has great implications to the scientific management for local government%沉积物中不同形态的磷具有不同的地球化学行为和生物有效性,其含量和分布特征包含着许多环境地球化学信息.该文利用SMT法对扎龙湿地

  8. National Wetlands Inventory Lines

    Data.gov (United States)

    Minnesota Department of Natural Resources — Linear wetland features (including selected streams, ditches, and narrow wetland bodies) mapped as part of the National Wetlands Inventory (NWI). The National...

  9. A LOW-COST THREE-DIMENSIONAL SAMPLE COLLECTION ARRAY TO EVALUATE AND MONITOR CONSTRUCTED WETLANDS

    Science.gov (United States)

    Artificially constructed wetlands are gaining acceptance as a low cost treatment alternative to remove a number of undesirable constituents from water. Wetlands can be used to physically remove compounds such as suspended solids through sedimentation. Dissolved nutrients, biochemical oxygen demand, ...

  10. Environmental controls on the distribution of organic matter in recent sediments of the western continental margin of India

    Digital Repository Service at National Institute of Oceanography (India)

    Paropkari, A.L.; Rao, Ch.M.; Murty, P.S.N.

    A large number of surficial sediment samples from the western continental shelf and slope regions were analysed for the organic carbon and total nitrogen content. The organic carbon and nitrogen contents of these sediments exhibit marked regional...

  11. Terrestrial Ecosystems - Surficial Lithology of the Conterminous United States

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The U.S. Geological Survey (USGS) has generated a new classification and map of the lithology of surficial materials for the contiguous United States. This was...

  12. Surficial Geologic Map and Groundwater Resources of Woodstock, Vermont

    Data.gov (United States)

    Vermont Center for Geographic Information — Digital data from VG06-5 DeSimone, D., 2006,�Surficial Geologic Map and Groundwater Resources of Woodstock, Vermont: Vermont Geological Survey Open-File Report...

  13. Surficial Geologic Map of the Bristol Quadrangle, Vermont

    Data.gov (United States)

    Vermont Center for Geographic Information — Digital data from VG13-2 Springston, G, and Kim, J, 2013, Surficial Geologic Map of the Bristol Quadrangle, Vermont: Vermont Geological Survey Open File Report...

  14. Concentrations of DDTs and dieldrin in Long Island Sound sediment.

    Science.gov (United States)

    Yang, Lijia; Li, Xiqing; Zhang, Pengfei; Melcer, Michael E; Wu, Youxian; Jans, Urs

    2012-03-01

    The concentrations of three frequently detected organochlorine pesticides (OCPs) and one degradation product, p,p'-DDT, p,p'-DDD, dieldrin, and p,p'-DDE were determined in recently collected (2005-2006) and archived (1986-1989) surficial sediments and sediment cores from Long Island Sound (LIS). The concentration of dieldrin ranged from 0.05 to 5.27 ng g(-1) dry weight in the surficial sediments, and from 0.05 to 11.7 ng g(-1) dry weight in the sediment cores. Total DDXs (the sum of p,p'-DDE, p,p'-DDD and p,p'-DDT) concentrations ranged from 1.31 to 33.2 ng g(-1) in surficial sediments and 1.11 to 66.4 ng g(-1) in sediment cores. The results indicate that the three OCPs and DDE were still widely present in LIS surficial sediments two decades after the use of these pesticides in the United States was banned. In addition, the surficial concentrations did not decrease significantly when compared to the concentrations in archived samples collected two decades ago. Sediments in the western part of LIS were more contaminated (with concentrations in some western sites being still above probable effect levels) than those in the eastern part, probably as a result of the net westward sediment transport in LIS. The three OCPs and DDE were detected at all depths (down to ~50 cm) in the sediment cores, and concentration profiles indicated a depositional sedimentary environment with significant sediment mixing. Such mixing may redistribute OCPs deposited earlier (deeper in sediment bed) to the sediment surface and lead to enhanced persistence of OCP concentrations in surficial sediments. This journal is © The Royal Society of Chemistry 2012

  15. Geochronological arguments for a close relationship between surficial formation profiles and environmental crisis (c. 3000-2000 BP) in Gabon (Central Africa)

    Science.gov (United States)

    Thiéblemont, Denis; Flehoc, Christine; Ebang-Obiang, Michel; Rigollet, Christophe; Prian, Jean-Pierre; Prognon, François

    2013-07-01

    We present new 14C data on charcoal fragments recovered from the lower (coarse-grained Stone Line) and upper (fine-grained Cover Horizon) portions of surficial formation profiles in Gabon. These data and others compiled from the literature enable a reconstruction of the Upper Holocene geological regional history of Gabon. The connection between the geological events recorded in the surficial formations and the Upper Holocene environmental crisis is discussed and a scenario connecting geological events with climatic and environmental changes is proposed. Such a scenario suggests that following the climatic crisis, the reconstitution of soils by aeolian sedimentation could have been an important factor of Bantu expansion.

  16. Project plan-Surficial geologic mapping and hydrogeologic framework studies in the Greater Platte River Basins (Central Great Plains) in support of ecosystem and climate change research

    Science.gov (United States)

    Berry, Margaret E.; Lundstrom, Scott C.; Slate, Janet L.; Muhs, Daniel R.; Sawyer, David A.; VanSistine, D. Paco

    2011-01-01

    The Greater Platte River Basin area spans a central part of the Midcontinent and Great Plains from the Rocky Mountains on the west to the Missouri River on the east, and is defined to include drainage areas of the Platte, Niobrara, and Republican Rivers, the Rainwater Basin, and other adjoining areas overlying the northern High Plains aquifer. The Greater Platte River Basin contains abundant surficial deposits that were sensitive to, or are reflective of, the climate under which they formed: deposits from multiple glaciations in the mountain headwaters of the North and South Platte Rivers and from continental ice sheets in eastern Nebraska; fluvial terraces (ranging from Tertiary to Holocene in age) along the rivers and streams; vast areas of eolian sand in the Nebraska Sand Hills and other dune fields (recording multiple episodes of dune activity); thick sequences of windblown silt (loess); and sediment deposited in numerous lakes and wetlands. In addition, the Greater Platte River Basin overlies and contributes surface water to the High Plains aquifer, a nationally important groundwater system that underlies parts of eight states and sustains one of the major agricultural areas of the United States. The area also provides critical nesting habitat for birds such as plovers and terns, and roosting habitat for cranes and other migratory birds that travel through the Central Flyway of North America. This broad area, containing fragile ecosystems that could be further threatened by changes in climate and land use, has been identified by the USGS and the University of Nebraska-Lincoln as a region where intensive collaborative research could lead to a better understanding of climate change and what might be done to adapt to or mitigate its adverse effects to ecosystems and to humans. The need for robust data on the geologic framework of ecosystems in the Greater Platte River Basin has been acknowledged in proceedings from the 2008 Climate Change Workshop and in draft

  17. Characterization of sediment and measurement of groundwater levels and temperatures, Camas National Wildlife Refuge, eastern Idaho

    Science.gov (United States)

    Twining, Brian V.; Rattray, Gordon W.

    2016-11-02

    The Camas National Wildlife Refuge (Refuge) in eastern Idaho, established in 1937, contains wetlands, ponds, and wet meadows that are essential resting and feeding habitat for migratory birds and nesting habitat for waterfowl. Initially, natural sources of water supported these habitats. However, during the past few decades, climate change and changes in surrounding land use have altered and reduced natural groundwater and surface water inflows such that the wetlands, ponds, and wet meadows are now maintained through water management and groundwater pumping. These water management activities have proven to be inefficient and costly, prompting the Refuge to develop alternative water management options that are more efficient and less expensive. The U.S. Geological Survey, in cooperation with the U.S. Fish and Wildlife Service, is studying the hydrogeology at the Refuge to provide information for developing alternative water management options.The hydrogeologic studies at the Refuge included characterizing the type, distribution, and hydraulic conductivity of surficial sediments and measuring water levels and temperatures in monitoring wells. Four monitoring wells and seven soil probe coreholes were drilled at the Refuge. Seven water level and temperature data loggers were installed in the wells and water levels and temperatures were continuously recorded from November 2014 to June 2016. Sediment cores were collected from the coreholes and sediment type and distribution were characterized from drillers’ notes, geophysical logs, corehole samples, and particle grain-size analysis. The hydraulic conductivities of sediments were estimated using the measured average grain size and the assumed textural maturity of the sediment, and ranged from about 20 to 290 feet per day.

  18. Restoring Wetlands

    Institute of Scientific and Technical Information of China (English)

    WANG HAIRONG

    2011-01-01

    Watching flocks of waterfowl taking off and landing in the large expanse of wetland near his home is a favorite pastime of Li Qiwen a middle-aged primary school teacher in Weichang Township,Luobei County in Heilongjiang Province.The wetland is home to hundreds of species of birds,including rare white storks and red-crowned cranes,as well as more common geese and ducks.

  19. Ecosystem function in oil sands wetlands : rates of detrital decomposition, moss growth, and microbial respiration in oilsands wetlands

    Energy Technology Data Exchange (ETDEWEB)

    Wytrykush, C. [Windsor Univ., ON (Canada); Hornung, J. [Petro-Canada, Calgary, AB (Canada)

    2007-07-01

    A study was conducted in which leaf litter breakdown and biomass accrual in 31 reference and oilsands affected (OSPM) wetlands in Northeastern Alberta was examined. The purpose was to determine how the decomposition of dead plant matter controls the primary productivity in wetlands. The data collected from this study will provide information about carbon flow and dynamics in oilsands affected wetlands. The study involved the investigation of wetlands that contrasted in water origin (OSPM vs. reference), sediment origin (OSPM vs. natural), sediment organic content and age. Mesh bags containing 5 g of dried Typha (cattail) or 20 g of damp moss were placed into 31 wetlands in order to monitor the rate at which biomass was lost to decomposition, as measured by changes in dry mass. After 1 year, moss growth was found to be greatest in younger wetlands with natural sediments. Cattail decomposition was found to be slower in wetlands containing OSPM water than that in reference wetlands. Preliminary analysis of respiration rates of biota associated with decomposing cattail indicate that the amount of oxygen consumed is not affected by wetland water source, sediment source, level of initial sediment organic content, or age.

  20. What Makes a Wetland a Wetland?

    Science.gov (United States)

    Naturescope, 1986

    1986-01-01

    Provides descriptions of and activities about various kinds of wetlands. Contains seven learning activities ranging from creating wetland scenes with picture cutouts to actually exploring a wetland. Includes reproducible handouts and worksheets for several of the activities. (TW)

  1. Virginia ESI: Wetlands (Wetland Polygons)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing the coastal wetlands for Virginia, classified according to the Environmental Sensitivity Index (ESI)...

  2. 模拟湿地生境升温条件下湿地底泥——水体磷元素循环特征%Characteristics of Phosphorus Cycling between Sediment of the Wetlands and Water under Warming in Simulated Wetland Habitat

    Institute of Scientific and Technical Information of China (English)

    王行; 张志剑; 李津津; 徐心

    2011-01-01

    Climate warming impacts the global ecosystems extensively, especially for the phosphorus biogeo-chemical cycle in wetlands, which is of particular interest in light of water quality security. Six wetlands with large spatial patterns in carbon and phosphorus contents were selected for this study. The sediment samples in these test wetlands were incubated under a field temperature-controlled platform based on the microcosm principle and were incubated with ambient water temperature (control treatment) and with 5 °C-increased water temperature (the warming treatment). The results indicated that the warming promoted the release of phosphorus from the sediments of the wetlands to pore water, then upward into overlying water. Seasonally, the sediments with high contents of iron-bind phosphorus had the significant changes in total phosphorus and dissolved reactive phosphorus in overlying-water, especially the magnitude of phosphorus release in summer was greater than in winter. Due to the much higher phosphorus concentration in the pore water than in the overlying water, the sediments in the wetlands can act as nutrient sources in response to warming. An enhanced amount and concentration of phosphorus in pore water in response to warming might result in a higher risk of phosphorus release toward overlying water in the future. The warming increased the phosphatase activities in the sediments of the wetlands, especially to the wetlands with low phosphorus contents, indicating a rapid decomposition of organic phosphorus components. The enhanced labile carbon pools and the fast degradation of organic matter subjected to warming might act as 2 main factors responsible for the high release of phosphorus.%气候变暖对全球生态系统产生了广泛的影响,这其中包括与水质安全和水质演变密切有关的湿地磷元素生物地球化学循环.以长三角南区6块磷库与碳库具有显著差异的湿地为研究对象,通过基于微宇宙原理的湿地

  3. Potential effects of deepening the St. Johns River navigation channel on saltwater intrusion in the surficial aquifer system, Jacksonville, Florida

    Science.gov (United States)

    Bellino, Jason C.; Spechler, Rick M.

    2013-01-01

    The U.S. Army Corps of Engineers (USACE) has proposed dredging a 13-mile reach of the St. Johns River navigation channel in Jacksonville, Florida, deepening it to depths between 50 and 54 feet below North American Vertical Datum of 1988. The dredging operation will remove about 10 feet of sediments from the surficial aquifer system, including limestone in some locations. The limestone unit, which is in the lowermost part of the surficial aquifer system, supplies water to domestic wells in the Jacksonville area. Because of density-driven hydrodynamics of the St. Johns River, saline water from the Atlantic Ocean travels upstream as a saltwater “wedge” along the bottom of the channel, where the limestone is most likely to be exposed by the proposed dredging. A study was conducted to determine the potential effects of navigation channel deepening in the St. Johns River on salinity in the adjacent surficial aquifer system. Simulations were performed with each of four cross-sectional, variable-density groundwater-flow models, developed using SEAWAT, to simulate hypothetical changes in salinity in the surficial aquifer system as a result of dredging. The cross-sectional models were designed to incorporate a range of hydrogeologic conceptualizations to estimate the effect of uncertainty in hydrogeologic properties. The cross-sectional models developed in this study do not necessarily simulate actual projected conditions; instead, the models were used to examine the potential effects of deepening the navigation channel on saltwater intrusion in the surficial aquifer system under a range of plausible hypothetical conditions. Simulated results for modeled conditions indicate that dredging will have little to no effect on salinity variations in areas upstream of currently proposed dredging activities. Results also indicate little to no effect in any part of the surficial aquifer system along the cross section near River Mile 11 or in the water-table unit along the cross

  4. Archive of sediment physical properties and grain-size data for sediment samples collected offshore of Assateague Island, Maryland and Virginia

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data release serves as an archive of sediment physical properties and grain-size data for surficial samples collected offshore of Assateague Island, Maryland...

  5. Examining water quality effects of riparian wetland loss and restoration scenarios in a southern ontario watershed.

    Science.gov (United States)

    Yang, Wanhong; Liu, Yongbo; Ou, Chunping; Gabor, Shane

    2016-06-01

    Wetland conservation has two important tasks: The first is to halt wetland loss and the second is to conduct wetland restoration. In order to facilitate these tasks, it is important to understand the environmental degradation from wetland loss and the environmental benefits from wetland restoration. The purpose of the study is to develop SWAT based wetland modelling to examine water quality effects of riparian wetland loss and restoration scenarios in the 323-km(2) Black River watershed in southern Ontario, Canada. The SWAT based wetland modelling was set up, calibrated and validated to fit into watershed conditions. The modelling was then applied to evaluate various scenarios of wetland loss from existing 7590 ha of riparian wetlands (baseline scenario) to 100% loss, and wetland restoration up to the year 1800 condition with 11,237 ha of riparian wetlands (100% restoration). The modelling was further applied to examine 100% riparian wetland loss and restoration in three subareas of the watershed to understand spatial pattern of water quality effects. Modelling results show that in comparing to baseline condition, the sediment, total nitrogen (TN), and total phosphorus (TP) loadings increase by 251.0%, 260.5%, and 890.9% respectively for 100% riparian wetland loss, and decrease by 34.5%, 28.3%, and 37.0% respectively for 100% riparian wetland restoration. Modelling results also show that as riparian wetland loss increases, the corresponding environmental degradation worsens at accelerated rates. In contrast, as riparian wetland restoration increases, the environmental benefits improve but at decelerated rates. Particularly, the water quality effects of riparian wetland loss or restoration show considerable spatial variations. The watershed wetland modelling contributes to inform decisions on riparian wetland conservation or restoration at different rates. The results further demonstrate the importance of targeting priority areas for stopping riparian wetland loss

  6. Coastal Wetlands.

    Science.gov (United States)

    Area Cooperative Educational Services, New Haven, CT. Environmental Education Center.

    This material includes student guide sheets, reference materials, and tape script for the audio-tutorial unit on Inland Wetlands. A set of 35mm slides and an audio tape are used with the materials. The material is designed for use with Connecticut schools, but it can be adapted to other localities. The unit materials emphasize the structure,…

  7. Urban wetlands

    NARCIS (Netherlands)

    Van der Salm, N.; Bellmann, C.; Hoeijmakers, S.

    2014-01-01

    This "designers' manual" is made during the TIDO-course AR0533 Innovation & Sustainability. This is a manual meant for designers who are interested in water purifications within the boundaries of a project, presenting constructed wetlands. It is a guide to quickly provide you with project relevant

  8. The Quality Status and Preliminary Ecological Risk Assessment of Sediments of Xixi Wetland, China%西溪湿地底泥质量现状与生态风险初步评价

    Institute of Scientific and Technical Information of China (English)

    申秀英; 潘腊青; 许惠英; 童国璋

    2013-01-01

    To understand the quality status of Xixi wetland sediments, sediment samples of different interference type were collected in pro-tection zones in September 2012, the contents of heavy metals, PCBs, PAHs and OCPs in sediment were tested, and the ecological risk of wet-land’s sediments was preliminarily assessed. The results showed that PCBs and OCPs were not detected in sediments, but 14 priority PAHs from USEPA were detected. Total PAHs concentration was in the range of 115.9~217.8 ng·g-1, which was under the effects range low (ERL) of potential ecological risk. Among them, total concentration of 7 PAHs blacklisted priority pollutants in China’s water was half of the total amount for 14 PAHs(average 50.08%). Although the average content of 8 heavy metals in sediments was lower than the secondary standard of Soil Environment Quality Standard (GB 15618-1995), the Hg, Zn, Pb, and Ni contents had been exceeded first standard in more than one sampling site. Using soil background values and national first standards as reference values, ecological risk of heavy metals in wetland sediments was preliminarily assessed by single factor pollution index method. It was found that pollution index of seven and four heavy metals were greater than 1, respectively. By comprehensive analysis to qualities of various interference type sediments, it had been showed that sedi-ment dredging could effectively reduce the contents of organic matter, total nitrogen and PAHs, but the contents of total phosphorus and heavy metals had no obvious effect. The dry pond measures of the closed aquifer could significantly reduce the amount of sludge and contents of or-ganic compound in sediments. The results also showed that the pollution levels of high ring PAHs and heavy metals in the Xixi wetland’s sediments might have potential biological toxicity and adverse ecological effect to wetland’s living things, but there was no ecological risk by using the dredged sediment as farming.%为了解

  9. On the Connections Between Surficial Processes and Stratigraphy in River Deltas

    CERN Document Server

    Puma, Michael J; Paola, Chris; Rinaldo, Andrea; Rodriguez-Iturbe, Ignacio

    2016-01-01

    We explore connections between surficial deltaic processes (e.g. avulsion, deposition) and the stratigraphic record using a simple numerical model of delta-plain evolution, with the aim of constraining these connections and thus improving prediction of subsurface features. The model represents channel dynamics using a simple but flexible cellular approach, and is unique in that it explicitly includes backwater effects that are known to be important in low-gradient channel networks. The patterns of channel deposits in the stratigraphic record vary spatially due to variation in avulsion statistics with radial distance from the delta's source of water and sediment. We introduce channel residence time as an important statistical measure of the surface channel kinematics. The model suggests that the mean channel residence time anywhere within the delta is nicely described by a power law distribution showing a cutoff that depends on radial distance. Thicknesses of channel deposits are not uniquely determined by the...

  10. Surficial Geologic Map of the Evansville, Indiana, and Henderson, Kentucky, Area

    Science.gov (United States)

    Moore, David W.; Lundstrom, Scott C.; Counts, Ronald C.; Martin, Steven L.; Andrews, William M.; Newell, Wayne L.; Murphy, Michael L.; Thompson, Mark F.; Taylor, Emily M.; Kvale, Erik P.; Brandt, Theodore R.

    2009-01-01

    The geologic map of the Evansville, Indiana, and Henderson, Kentucky, area depicts and describes surficial deposits according to their origin and age. Unconsolidated alluvium and outwash fill the Ohio River bedrock valley and attain maximum thickness of 33-39 m under Diamond Island, Kentucky, and Griffith Slough, south of Newburgh, Indiana. The fill is chiefly unconsolidated, fine- to medium-grained, lithic quartz sand, interbedded with clay, clayey silt, silt, coarse sand, granules, and gravel. Generally, the valley fill fines upward from the buried bedrock surface: a lower part being gravelly sand to sandy gravel, a middle part mostly of sand, and a surficial veneer of silt and clay interspersed with sandy, natural levee deposits at river's edge. Beneath the unconsolidated fill are buried and discontinuous, lesser amounts of consolidated fill unconformably overlying the buried bedrock surface. Most of the glaciofluvial valley fill accumulated during the Wisconsin Episode (late Pleistocene). Other units depicted on the map include creek alluvium, slackwater lake (lacustrine) deposits, colluvium, dune sand, loess, and sparse bedrock outcrops. Creek alluvium underlies creek floodplains and consists of silt, clayey silt, and subordinate interbedded fine sand, granules, and pebbles. Lenses and beds of clay are present locally. Silty and clayey slackwater lake (lacustrine) deposits extensively underlie broad flats northeast of Evansville and around Henderson and are as thick as 28 m. Fossil wood collected from an auger hole in the lake and alluvial deposits of Little Creek, at depths of 10.6 m and 6.4 m, are dated 16,650+-50 and 11,120+-40 radiocarbon years, respectively. Fossil wood collected from lake sediment 16 m below the surface in lake sediment was dated 33,100+-590 radiocarbon years. Covering the hilly bedrock upland is loess (Qel), 3-7.5 m thick in Indiana and 9-15 m thick in Kentucky, deposited about 22,000-12,000 years before present. Most mapped surficial

  11. Surficial geology of Hannibal Quadrangle, Oswego County, New York

    Science.gov (United States)

    Miller, Todd S.

    1981-01-01

    The location and extent of 10 kinds of surficial deposits in part of Hannibal quadrangle, Oswego County, N.Y., are mapped on a 7.5-minute U.S. Geological Survey topographic map. The map was compiled to indicate the lithology and potential for ground-water development at any specific location. (USGS)

  12. Digital data set describing surficial geology in the conterminous US

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This digital data set describes surficial geology of the conterminous United States. The data set was generated from a U.S. Geological Survey 1:7,500,000-scale map...

  13. Surficial geology of the Southwest Principal Aquifers (SWPA) study

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This is a 100-meter cell resolution raster dataset consisting of 1:750,000-scale surficial geology for California and 1:500,000-scale for Nevada, and parts of Utah,...

  14. Chincoteague Bay surface sediment physical parameters data from the spring and fall sampling trips of 2014

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Scientists from the U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center conducted a seasonal collection of surficial sediments from Chincoteague...

  15. Distribution of some biochemical compounds in the sediments of the Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Bhosle, N.B.; Dhople, V.M.

    Surficial sediment samples collected from the continental shelf and slope of the Bay of Bengal were studied for the distribution of organic carbon and its constituent fractions such as carbohydrates, proteins, amino acids and lipids. Organic carbon...

  16. Sediments of Block Island Sound acquired in 1966 (SAVARD66 shapefile)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A total of 84 surficial sediments samples were collected aboard two cruises from Block Island Sound as part of a Master's Thesis completed at the University of...

  17. Sediments of Block Island Sound acquired in 1966 (SAVARD66 shapefile)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A total of 84 surficial sediments samples were collected aboard two cruises from Block Island Sound as part of a Master's Thesis completed at the University of Rhode...

  18. Sediments of Block Island Sound acquired in 1966 (SAVARD66 shapefile)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A total of 84 surficial sediments samples were collected aboard two cruises from Block Island Sound as part of a Master's Thesis completed at the University of Rhode...

  19. Sediment Texture and Geomorphology of the Sea Floor from Fenwick Island, Maryland to Fisherman's Island, Virginia

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data are a qualitatively derived interpretive polygon shapefile defining surficial sediment type and distribution, and geomorphology, for nearly 1,400 square...

  20. Chincoteague Bay surface sediment physical parameters data from the spring and fall sampling trips of 2014

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Scientists from the U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center conducted a seasonal collection of surficial sediments from Chincoteague...

  1. Characterization and Placement of Wetlands for Integrated Conservation Practice Planning

    Science.gov (United States)

    Constructed wetlands have been recognized as an efficient and cost-effective conservation practice to protect water quality through reducing the transport of sediments and nutrients from upstream croplands to downstream water bodies. The challenge resides in targeting the strateg...

  2. National Wetlands Inventory Points

    Data.gov (United States)

    Minnesota Department of Natural Resources — Wetland point features (typically wetlands that are too small to be as area features at the data scale) mapped as part of the National Wetlands Inventory (NWI). The...

  3. National Wetlands Inventory Polygons

    Data.gov (United States)

    Minnesota Department of Natural Resources — Wetland area features mapped as part of the National Wetlands Inventory (NWI). The National Wetlands Inventory is a national program sponsored by the US Fish and...

  4. 弥苴河口湿地植物残体与底泥资源化利用研究%A Study on Resource Utilisation of Plant Residues and Sediment from Wetlands of Miju River Estuary

    Institute of Scientific and Technical Information of China (English)

    郑潭; 陈建中; 戴丽; 王志芸

    2012-01-01

    应用双室堆沤肥技术,以弥苴河口湿地植物残体、湿地底泥和当地养殖业废物制成双室堆沤肥,按不同配比设计5种施肥处理方案进行还田试验。对比研究施肥前后的蔬菜产量、蔬菜品质、土壤肥力以及土壤根际微生物,发现:方案A[50%-60%植物残体(收割物)+40%-50%养殖业废物+微生物菌剂(3kg/t),活性液体肥作追肥。农药同习惯施肥对增加蔬菜产量、提高蔬菜品质、增加土壤肥力和改善土壤微生态环境效果最好。在实际应用中也可适当增加10%-20%的湿地底泥,相应减少养殖业废物量。%By using a dual-chamber composting heap technology for plant residues and sediment from wetlands of Miju River estuary as well as local livestock farming wastes, compost in five different proportionings was made to apply to the fields. The yield and quality of vegetables, fertility and rhizospheric microorganisms of the soil before and after the fertiliser applications were compared. The field tests showed that Scenario A (50% to 60% harvesting material of plant residues + 40% to 50% livestock farming wastes + 3 kg microbial agent per tonne, with active liquid manure as topdressing and conventional type of pesticide usage) could enhance the vegetable yield and quality, improve fertility and microecosystem of the soil the best. In practice, 10% to 20% increase in wetland sediment with corresponding decrease in livestock farming wastes may be suitable as well.

  5. Holocene fluctuations of Quelccaya Ice Cap, Peru based on lacustrine and surficial geologic archives

    Science.gov (United States)

    Stroup, J. S.; Kelly, M. A.; Lowell, T. V.; Beal, S. A.; Smith, C. A.

    2013-12-01

    Peru's Quelccaya Ice Cap (QIC; 13.9°S, 70.8°W, ~5200-5670 m asl) is an important site for understanding tropical paleoclimate, mainly because of annually layered ice cores that provide an ~1800 year long record of tropical paleoclimatic conditions (e.g., Thompson et al., 2013). Here, we present a detailed record of QIC fluctuations using surficial deposits and lake sediments that extend back to late glacial time. We compare the late Holocene records of QIC 10Be-dated moraines and ice core data with lake sediments from a nearby glacially fed lake to establish the framework we use to interpret a Holocene long sediment record from a glacially fed lake. We also examine sediments from a nearby non-glacial lake to constrain non-glacial clastic input. We collected two ~5 m-long sediment cores, one from Laguna Challpacocha, which is currently fed by QIC meltwater, and one from the Laguna Yanacocha, which has not received QIC meltwater since ~12.3 ka. Changes in magnetic susceptibility, loss on ignition, bulk density and X-ray fluorescence chemistry combined with 14C and 210Pb chronologies provide information about sediment transported to the lakes. Retreat from the late Holocene extent defined by the 10Be-dated moraine record (~0.52 ka) is contemporaneous with a sharp transition from organic to clastic sedimentation in the Challpacocha core at ~ 0.52 ka. This implies that glacially-sourced clastic sedimentation, as tracked by loss on ignition, Ti counts and bulk density, increased during ice cap recession. Based on these same proxy data, we suggest the following Holocene history of QIC: QIC receded from the Challpacocha basin by ~10.6 ka. Increased clastic sedimentation at 8.2 - 4.1, 3.6 - 2.7 ka and from 0.55 ka - present are interpreted as times of ice cap recession. The increased clastic sedimentation at ~8.2 - 4.1 ka is consistent with surficial deposits near the present-day ice margin that indicate that at ~7.0 - 4.6 ka QIC was smaller than at present (Buffen et al

  6. Carbon sequestration in two created riverine wetlands in the midwestern United States.

    Science.gov (United States)

    Bernal, Blanca; Mitsch, William J

    2013-07-01

    Wetlands have the ability to accumulate significant amounts of carbon (C) and thus could provide an effective approach to mitigate greenhouse gas accumulation in the atmosphere. Wetland hydrology, age, and management can affect primary productivity, decomposition, and ultimately C sequestration in riverine wetlands, but these aspects of wetland biogeochemistry have not been adequately investigated, especially in created wetlands. In this study we investigate the ability of created freshwater wetlands to sequester C by determining the sediment accretion and soil C accumulation of two 15-yr-old created wetlands in central Ohio-one planted and one naturally colonized. We measured the amount of sediment and soil C accumulated over the parent material and found that these created wetlands accumulated an average of 242 g C m yr, 70% more than a similar natural wetland in the region and 26% more than the rate estimated for these same wetlands 5 yr before this study. The C sequestration of the naturally colonized wetland was 22% higher than that of the planted wetland (267 ± 17 vs. 219 ± 15 g C m yr, respectively). Soil C accrual accounted for 66% of the aboveground net primary productivity on average. Open water communities had the highest C accumulation rates in both wetlands. This study shows that created wetlands can be natural, cost-effective tools to sequester C to mitigate the effect of greenhouse gas emissions.

  7. Kansas Playa Wetlands

    Data.gov (United States)

    Kansas Data Access and Support Center — This digital dataset provides information about the distribution, areal extent, and morphometry of playa wetlands throughout western Kansas. Playa wetlands were...

  8. Gulf of Mexico Integrated Science - Tampa Bay Study - Characterization of Tidal Wetlands

    Science.gov (United States)

    McIvor, Carole

    2005-01-01

    Tidal wetlands in Tampa Bay, Florida, consist of mangrove forests and salt marshes. Wetlands buffer storm surges, provide fish and wildlife habitat, and enhance water quality through the removal of water-borne nutrients and contaminants. Substantial areas of both mangroves and salt marshes have been lost to agricultural, residential, and industrial development in this urban estuary. Wetlands researchers are characterizing the biological components of tidal wetlands and examining the physical factors such as salinity, tidal flushing, and sediment deposition that control the composition of tidal wetland habitats. Wetlands restoration is a priority of resource managers in Tampa Bay. Baseline studies such as these are needed for successful restoration planning and evaluation.

  9. Sedimentation within and among mangrove forests along a gradient of geomorphological settings

    NARCIS (Netherlands)

    Adame, Maria Fernanda; Neil, David; Wright, Sara F.; Lovelock, Catherine E.

    2010-01-01

    Coastal wetlands provide important ecological services to the coastal zone, one of which is sediment retention. In this study we investigated sediment retention across a range of geomorphological settings and across vegetation zones comprising coastal wetlands. We selected six coastal wetlands domin

  10. Surficial Geology of Mount Rainier National Park, Washington

    Science.gov (United States)

    Crandell, Dwight Raymond

    1969-01-01

    Much of the ground surface around Mount Rainier volcano is directly underlain by loose geologic deposits that veneer the hard rock formations. Examples of these deposits are sand and gravel bars along the rivers, ridges of loose rock debris beside the glaciers, and sloping aprons of rock fragments beneath almost every cliff. Even though they are generally thin and inconspicuous when compared with the rock formations, these surficial deposits are clues to geologic events that have profoundly influenced the shape of the park's landscape. Thus, from the character and extent of glacial deposits one can judge the age and size of former glaciers that carved the cirques and deep canyons of the park; from the mudflows which streamed down nearly every valley one can infer the age and size of huge landslides of the past that helped determine Mount Rainier's present shape; and from the pumice deposits some of the volcano's recent eruptive activity can be reconstructed. The map (plate 1, in pocket) that accompanies this description of the surficial deposits of Mount Rainier National Park shows the location of the various geologic formations, and the explanation shows the formations arranged in order of their relative age, with the oldest at the bottom. The text describes the surficial deposits in sequence from older to younger. A discussion of the pumice deposits of the park, which were not mapped, is followed by a description of the formations shown on the geologic map. Inspection of the geologic map may lead the viewer to question why the surficial deposits are shown in more detail in a zone several miles wide around the base of the volcano than elsewhere. This is partly because the zone is largely near or above timberline, relatively accessible, and the surficial deposits there can be readily recognized, differentiated, and mapped. In contrast, access is more difficult in the heavily timbered parts of the park, and surficial deposits there are generally blanketed by a dense

  11. Do geographically isolated wetlands influence landscape functions?

    Science.gov (United States)

    Cohen, Matthew J; Creed, Irena F; Alexander, Laurie; Basu, Nandita B; Calhoun, Aram J K; Craft, Christopher; D'Amico, Ellen; DeKeyser, Edward; Fowler, Laurie; Golden, Heather E; Jawitz, James W; Kalla, Peter; Kirkman, L Katherine; Lane, Charles R; Lang, Megan; Leibowitz, Scott G; Lewis, David Bruce; Marton, John; McLaughlin, Daniel L; Mushet, David M; Raanan-Kiperwas, Hadas; Rains, Mark C; Smith, Lora; Walls, Susan C

    2016-02-23

    Geographically isolated wetlands (GIWs), those surrounded by uplands, exchange materials, energy, and organisms with other elements in hydrological and habitat networks, contributing to landscape functions, such as flow generation, nutrient and sediment retention, and biodiversity support. GIWs constitute most of the wetlands in many North American landscapes, provide a disproportionately large fraction of wetland edges where many functions are enhanced, and form complexes with other water bodies to create spatial and temporal heterogeneity in the timing, flow paths, and magnitude of network connectivity. These attributes signal a critical role for GIWs in sustaining a portfolio of landscape functions, but legal protections remain weak despite preferential loss from many landscapes. GIWs lack persistent surface water connections, but this condition does not imply the absence of hydrological, biogeochemical, and biological exchanges with nearby and downstream waters. Although hydrological and biogeochemical connectivity is often episodic or slow (e.g., via groundwater), hydrologic continuity and limited evaporative solute enrichment suggest both flow generation and solute and sediment retention. Similarly, whereas biological connectivity usually requires overland dispersal, numerous organisms, including many rare or threatened species, use both GIWs and downstream waters at different times or life stages, suggesting that GIWs are critical elements of landscape habitat mosaics. Indeed, weaker hydrologic connectivity with downstream waters and constrained biological connectivity with other landscape elements are precisely what enhances some GIW functions and enables others. Based on analysis of wetland geography and synthesis of wetland functions, we argue that sustaining landscape functions requires conserving the entire continuum of wetland connectivity, including GIWs.

  12. Nitrogen and Sediment Capture of a Floating Treatment Wetland on an Urban Stormwater Retention Pond—The Case of the Rain Project

    OpenAIRE

    Brendan McAndrew; Changwoo Ahn; Joanna Spooner

    2016-01-01

    Nitrogen is widely recognized as a chronic urban stormwater pollutant. In the United States, wet retention ponds have become widely used to treat urban runoff for quantity and quality. While wet ponds typically function well for the removal of sediments, nitrogen removal, performance can be inconsistent due to poor design and/or lack of maintenance. Retrofitting ponds to improve their nitrogen capture performance, however, is often expensive. By hydroponically growing macrophytes on wet ponds...

  13. Nitrogen fixation (Acetylene reduction) in the sediments of the pluss-see : with special attention to the role of sedimentation

    NARCIS (Netherlands)

    Blauw, T.S.

    1987-01-01

    Sediments of productive lakes are usually rich in organic matter and, except for a thin surficial layer, anaerobic. These conditions seem to be favourable for heterotrophic nitrogen fixation. However, these sediments also contain relatively high ammonium concentrations. Ammonium represses

  14. Hydrostratigraphic Framework and Selection and Correlation of Geophysical Log Markers in the Surficial Aquifer System, Palm Beach County, Florida

    Science.gov (United States)

    Reese, Ronald S.; Wacker, Michael A.

    2007-01-01

    The surficial aquifer system is the major source of freshwater for public water supply in Palm Beach County, Florida, yet many previous studies of the hydrogeology of this aquifer system have focused only on the eastern one-half to one-third of the county in the more densely populated coastal area (Land and others, 1973; Swayze and others, 1980; Swayze and Miller, 1984; Shine and others, 1989). Population growth in the county has resulted in the westward expansion of urbanized areas into agricultural areas and has created new demands on the water resources of the county. Additionally, interest in surface-water resources of central and western areas of the county has increased. In these areas, plans for additional surface-water storage reservoirs are being made under the Comprehensive Everglades Restoration Plan originally proposed by the U.S. Army Corps of Engineers and the South Florida Water Management District (1999), and stormwater treatment areas have been constructed by the South Florida Water Management District. Surface-water and ground-water interactions in the Everglades are thought to be important to water budgets, water quality, and ecology (Harvey and others, 2002). Most of the previous hydrogeologic and ground-water flow simulation studies of the surficial aquifer system have not utilized a hydrostratigraphic framework, in which stratigraphic or sequence stratigraphic units, such as those proposed in Cunningham and others (2001), are delineated in this stratigraphically complex aquifer system. A thick zone of secondary permeability mapped by Swayze and Miller (1984) was not subdivided and was identified as only being within the Anastasia Formation of Pleistocene age. Miller (1987) published 11 geologic sections of the surficial aquifer system, but did not delineate any named stratigraphic units in these sections. This limited interpretation has resulted, in part, from the complex facies changes within rocks and sediments of the surficial aquifer

  15. Using hydrogeomorphic criteria to classify wetlands on Mt. Desert Island, Maine - approach, classification system, and examples

    Science.gov (United States)

    Nielsen, Martha G.; Guntenspergen, Glenn R.; Neckles, Hilary A.

    2005-01-01

    A wetland classification system was designed for Mt. Desert Island, Maine, to help categorize the large number of wetlands (over 1,200 mapped units) as an aid to understanding their hydrologic functions. The classification system, developed by the U.S. Geological Survey (USGS), in cooperation with the National Park Service, uses a modified hydrogeomorphic (HGM) approach, and assigns categories based on position in the landscape, soils and surficial geologic setting, and source of water. A dichotomous key was developed to determine a preliminary HGM classification of wetlands on the island. This key is designed for use with USGS topographic maps and 1:24,000 geographic information system (GIS) coverages as an aid to the classification, but may also be used with field data. Hydrologic data collected from a wetland monitoring study were used to determine whether the preliminary classification of individual wetlands using the HGM approach yielded classes that were consistent with actual hydroperiod data. Preliminary HGM classifications of the 20 wetlands in the monitoring study were consistent with the field hydroperiod data. The modified HGM classification approach appears robust, although the method apparently works somewhat better with undisturbed wetlands than with disturbed wetlands. This wetland classification system could be applied to other hydrogeologically similar areas of northern New England.

  16. Distribution Characteristics and Pollution Assessment of Heavy Metals in Surface Sediments in Dagu River Wetland%大沽河湿地表层沉积物重金属分布特征及污染评价

    Institute of Scientific and Technical Information of China (English)

    徐勇; 马绍赛; 陈聚法; 赵俊; 夏斌; 崔正国

    2012-01-01

    胶州湾属半封闭海湾,水体交换能力较弱,受多条河流人海影响,污染日趋加重,通过大沽河的径流量、输沙量和溶解污染物占到胶州湾人海河流的首位.根据区域特征,于2009年2、5、8、11月对大沽河湿地48个采样点表层沉积物中的Cu、Zn、Pb、Cd、Hg、As、有机碳、粒度进行测定,探讨了重金属含量和污染特征与总有机碳、粒度的关系,利用污染评价法和潜在生态风险评价法进行污染和风险分析.结果表明:胶州湾大沽河湿地表层沉积物重金属含量较低,大部分测站符合海洋沉积物质量(GB 18668-2002)Ⅰ类标准的要求.表层沉积物中Cu、Pb、Zn含量8月份最高、2月份次之、5月份最低.Pb、Hg、As 3种重金属含量在2月份最高.Cu、Pb、Zn和Cd重金属之间存在显著正相关关系,Hg与As存在明显的相关关系:除Cd和As外的4种重金属与沉积物粘土、有机碳含量之间也存在显著正相关性.重金属单因子污染程度总体较轻,属于低污染水平,污染程度依次为Hg>Cd>Pb>Cu>As>Zn.大沽河河口区表层沉积物重金属潜在生态风险总体处于较低水平,风险程度依次为Hg>Cd>Pb>Cu>As>Zn.%Jiaozhou Bay is a semi-enclosed bay of weak water exchange capacity, the pollution is increasingly heavier for the rivers into the sea, the account of river runoff, sediment and dissolved pollutants into the sea through Dagu River are the first in all the rivers for Jiaozhou Bay. According to the characteristics of Dagu Kiver, the contents of Cu, Pb, Zn, Cd, Hg, As, clay and organic carbon in the 48 surface sediments samples in the wetland of Dagu River were measured, in February, May, August, November of 2009. Firstly, the content and distributed characteristics of these heavy metals, and the relevance with different particle size and organic carbon were discussed, and methods of pollution assessment and the potential ecological risk assessment were used

  17. Potential Ecological Risk Assessment of Heavy Metals in Superficial Sediments of Yuehai Wetland%银川阅海湿地沉积物重金属潜在生态危害评价

    Institute of Scientific and Technical Information of China (English)

    朱嵬; 倪细炉

    2014-01-01

    In order to investigate heavy metal pollution and its potential ecological risk in sediments of Yuehai wetland, content and accumulation of heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb, Zn) were investigated. The highest values for heavy metals concentrations in sediments before the modern industrialization of the world and the natural background values were used to analyze the accumulation coefficient and potential ecological risk (PER) coefficients for heavy metal. The PER index for each sample location was also discussed. The method for evaluating PER index presented by Lars Hankanson was applied to assess the ecological risk. The results showed that when the highest values for heavy metals concentrations in sediments before the modern industrialization of the world were taken as references, the accumulation order for those heavy metals was Cr>Pb>Zn>Cu>As>Cd>Hg, the potential risk order of elements was Cd>As>Hg>Pb>Cu>Cr>Zn. The 4th sample point was under the highest potential risk,, which is much higher than other elements, the while the others had relatively small risk. To sum up, the potential ecological risk of Yuehai wetland was light, at least not very serious.%为确定银川市阅海湿地湖水底泥中重金属的污染状态及潜在的生态危险,笔者采集了该湿地底泥,分析了8种常见重金属(As、 Cd、 Cr、 Cu、 Hg、 Ni、 Pb、 Zn)的含量及富集情况,又以现代工业化前正常颗粒底泥中重金属含量的最高背景值和自然背景值为参比值,对湿地底泥重金属的富集系数、生态危害系数及各采样点的生态危害指数进行探讨,最后运用 Lars Hankanson 潜在生态危害指数法对湿地底泥中重金属的生态危害程度做了评价。结果表明:以现代工业化前正常颗粒底泥中重金属含量的最高背景值为参比值,阅海湿地重金属富集顺序为 Cr>Pb>Zn>Cu>As>Cd>Hg;各重金属单因子生态危害程度为 Cd

  18. Nature and Composition of Planetary Surficial Deposits and Their Relationship to Planetary Crusts

    Science.gov (United States)

    McLennan, S. M.

    2010-12-01

    Planetary soils constitute micron to meter sized debris blankets covering all or parts of the surfaces of many planetary bodies. Recent results from the Martian surface, by the MER rovers and Phoenix lander, the Huygens probe at Titan and perhaps even the NEAR mission to asteroid 433 Eros suggest a continuum between classic planetary soils, such as those on the Moon, and conventional sediments, such as those on Earth. Controls on this variation are governed by complex interactions related to (1) impact and volcanic history, (2) presence and nature of atmospheres (and thus climate), (3) occurrence, composition and physical state of near-surface volatiles (e.g., water, methane), and (4) presence and nature of crustal tectonics, crustal evolution, and so forth. The Moon represents one extreme where surficial deposits result almost exclusively from impact processes. Absence of water and air restrict further reworking or transport on a significant scale after initial deposition. Disruption and mixing of lunar soils takes place but is related to impact gardening operating on relatively local scales and largely in a vertical sense; alteration is restricted to space weathering. The effect is that lunar soils are compositionally variable and match the composition of the crust in the vicinity of where they form. Thus lunar soils in the highlands are fundamentally different in composition than those on maria. Earth provides the other extreme where the highly dynamic geochemical and geophysical nature of the surface precludes preservation of classic planetary soils, although analogs may exist in ejecta blankets and eolian loess. Instead, a complex suite of sedimentary deposits form in response to chemical and physical weathering, erosion, transport and deposition by a variety of mechanisms involving water, wind, ice and biology. Although there is substantial sedimentary lithological differentiation (e.g., shales, sands, carbonates, evaporites), greatly influenced by the

  19. Pollution assessment and source identifications of polycyclic aromatic hydrocarbons in sediments of the Yellow River Delta, a newly born wetland in China.

    Science.gov (United States)

    Yang, Zhifeng; Wang, Lili; Niu, Junfeng; Wang, Jingyi; Shen, Zhenyao

    2009-11-01

    The levels and possible sources of 16 priority polycyclic aromatic carbons (PAHs) in the sediments from the Yellow River Delta (YRD) were investigated. The total PAH concentrations ranged from 23.9 to 520.6 microg kg(-1) with a mean value of 150.9 microg kg(-1), indicating low or medium levels compared with reported values of other deltas. The concentrations of the 16 individual PAHs presented varied profiles among different regions. The ecological risk assessment of PAHs showed that adverse effects would rarely occur in the sediments of the YRD based on the effect range-low quotients and the probability risk assessment. The PAH compositions and the principal component analysis (PCA) with multiple linear regression (MLR) uniformly presumed the mixed sources of pyrogenic- and petrogenic-deriving PAHs in the YRD. By PCA with MLR, the contributions of major sources were quantified as 36.4% from oil burning, 33.1% from biomass combustion, and 30.5% from diesel emission sources.

  20. National Status and Trends: Bioeffects Program: Magnitude and Extent of Sediment Toxicity of South Carolina and Georgia

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Surficial sediment samples were collected from 162 locations within five estuaries - Charleston Harbor, Winyah Bay, Leadenwah Creek, Savannah River, and St. Simons...

  1. Distribution of some biochemical compounds in sediments of the shelf and slope regions of the west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Bhosle, N.B.; Dhargalkar, V.K.; Braganca, A.

    Surficial sediment samples collected from the continental shelf and slope of the Bay of Bengal were studied for the distribution of organic carbon and its constituent fractions such as carbohydrates, proteins, amino acids and lipids. Organic carbon...

  2. Surficial geology of the sea floor in Long Island Sound offshore of Plum Island, New York

    Science.gov (United States)

    McMullen, K.Y.; Poppe, L.J.; Danforth, W.W.; Blackwood, D.S.; Schaer, J.D.; Ostapenko, A.J.; Glomb, K.A.; Doran, E.F.

    2010-01-01

    The U.S. Geological Survey (USGS), the Connecticut Department of Environmental Protection, and the National Oceanic and Atmospheric Administration (NOAA) have been working cooperatively to interpret surficial sea-floor geology along the coast of the Northeastern United States. NOAA survey H11445 in eastern Long Island Sound, offshore of Plum Island, New York, covers an area of about 12 square kilometers. Multibeam bathymetry and sidescan-sonar imagery from the survey, as well as sediment and photographic data from 13 stations occupied during a USGS verification cruise are used to delineate sea-floor features and characterize the environment. Bathymetry gradually deepens offshore to over 100 meters in a depression in the northwest part of the study area and reaches 60 meters in Plum Gut, a channel between Plum Island and Orient Point. Sand waves are present on a shoal north of Plum Island and in several smaller areas around the basin. Sand-wave asymmetry indicates that counter-clockwise net sediment transport maintains the shoal. Sand is prevalent where there is low backscatter in the sidescan-sonar imagery. Gravel and boulder areas are submerged lag deposits produced from the Harbor Hill-Orient Point-Fishers Island moraine segment and are found adjacent to the shorelines and just north of Plum Island, where high backscatter is present in the sidescan-sonar imagery.

  3. Ohio Uses Wetlands Program Development Grants to Protect Wetlands

    Science.gov (United States)

    The wetland water quality standards require the use of ORAM score to determine wetland quality. OEPA has also used these tools to evaluate wetland mitigation projects, develop performance standards for wetland mitigation banks and In Lieu Fee programs an.

  4. Wetlands in the ecological risk assessment process: A case study

    Energy Technology Data Exchange (ETDEWEB)

    Saban, L.B. [Roy F. Weston, Inc., Seattle, WA (United States)

    1995-12-31

    In the past few years, the ecological risk assessment (ERA) process as outlined in the EPA document Framework for Ecological Risk Assessment has been successfully used to assess risk to birds, mammals, aquatic organisms, plants, and to a limited extent, reptiles and amphibians, but has only recently been applied to wetlands. Due to the unique role that wetlands play in the environment as sources and sinks for nutrients, sediment retention, high productivity, habitat transition zones, aquifer recharge, high diversity and richness of biota, and aesthetic value, it is important to consider the entire wetland system in the ERA process. Because nearly sixty percent of Superfund sites are located in or near wetlands, a comprehensive approach is proposed to evaluate potential risks to flora and fauna in these wetland environments. Using the delineation and functional assessment techniques developed by wetland scientists, an estuarine wetland in western Washington was evaluated within the scope of ERA`S. The ERA was applied to the wetland using functional assessments as an integral part of the problem formulation phase of the risk assessment process. Applying the ERA process to wetlands enhances the functional assessment process and helps to define critical elements to evaluate within wetland systems. The results of this risk assessment help to define patches within a landscape that are potentially at risk and how to prioritize remedial actions.

  5. Trapping carbon in small ponds and wetlands

    Science.gov (United States)

    Quinton, J. N.; Ockenden, M. C.; Deasy, C.; Favaretto, N.

    2012-04-01

    There is no doubt that carbon (C) is on the move. Recent estimates have suggested that the global sediment flux in agricultural landscapes due to water and tillage erosion is 35±10 Pg C y-1. Some of this C is oxidised and lost to the atmosphere, other material may be deposited and burried in colluvium and some may be delivered through both surface and subsurface flow paths to surface waters. In many agricultural landscapes these surface waters may take the form of small ponds and wetlands (field wetlands). In this paper we explore the potential of field wetlands to trap particulate C and influence the fate of dissolved organic carbon within the context of a small agricultural catchments in England. Since 2008 the mitigation options for phosphorus and sediment project (MOPS) has established ten monitored field wetlands across three catchments in the UK at Crake Trees, Cumbria (silt soils, rainfall 1500 mm y-1), Whinton Hill Cumbria (sandy soils, rainfall 1200 mm y-1), Newton Rigg, Cumbria (Silt soils, rainfall c1200 mm y-1) and Loddington, Leicestershire (Clay soils, rainfall 650 mm y-1). Although originally designed to capture sediment and phosphorus, their potential for influencing catchment scale C dynamics is becoming apparent. The C contents of sediments from the three catchments are typically in the range of 1.8 - 3.0% at Crake Trees Catchment, 2.5 to 9% at Whinton Hill and 2.0 to 3.1 % at Crake Trees. At the high rainfall sites the wetlands trap upwards of 20 t y-1 of sediment equating to several hundred kilograms of C. There is also some evidence that the ponds and wetlands may influence DOC, with DOC concentrations falling from approximately 35 mg l-1 to 15 mg l-1 at the Whinton Hill site as water passes through a series of field wetlands. In this paper we will present data from the last two years of monitoring and consider the wider implications for C sequestration by ponds and wetlands in agricultural landscapes.

  6. The quality of our Nation's waters: water quality in the Northern Atlantic Coastal Plain surficial aquifer system, Delaware, Maryland, New Jersey, New York, North Carolina, and Virginia, 1988-2009

    Science.gov (United States)

    Denver, Judith M.; Ator, Scott W.; Fischer, Jeffrey M.; Harned, Douglas C.; Schubert, Christopher E.; Szabo, Zoltan

    2015-01-01

    The surficial aquifer system of the Northern Atlantic Coastal Plain is made up of unconfined aquifers that underlie most of the area. This aquifer system is a critical renewable source of drinking water and is the source of most flow to streams and of recharge to underlying confined aquifers. Millions of people rely on the surficial aquifer system for public and domestic water supply, in particular in the densely populated areas of Long Island, New York, and in southern New Jersey, but also in more rural areas. Because the aquifer sediments are permeable and the water table is shallow, the surficial aquifer system is vulnerable to contamination from chemicals that are applied to the land surface and carried into groundwater with infiltrating rainfall and snowfall.

  7. Detecting wetland changes in Shanghai, China using FORMOSAT and Landsat TM imagery

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Bo; Zhou, Yun-xuan; Thom, Ronald M.; Diefenderfer, Heida L.; Yuan, Qing

    2015-07-14

    Understanding the state of wetland ecosystems and their changes at the national and local levels is critical for wetland conservation, management, decision-making, and policy development practices. This study analyzed the wetlands in Shanghai, a province-level city, using remote sensing, image processing, and geographic information systems (GIS) techniques based on the Chinese national wetland inventory procedure and standards. FORMOSAT imagery acquired in 2012 and Navy nautical charts of the Yangtze estuarine area were used in conjunction with object-oriented segmentation, expert interpretation, and field validation to determine wetland status. Landsat imagery from 1985, 1995, 2000, 2003 and 2013 as well as social-economic data collected from 1985 to 2013 were used to further assess wetland changes. In 2013, Shanghai contained 376,970.6 ha of wetlands, and 78.8% of all wetlands were in marine or estuarine systems. Estuarine waters comprised the single largest wetland category. Between the first national wetland inventory in 2003 and the second national wetland inventory in 2013, Shanghai lost 50,519.13 ha of wetlands, amounting to a mean annual loss rate of 1.2% or an 11.8% loss over the decade. Declines were proportionately higher in marine and estuarine wetlands, with an annual loss of 1.8%, while there was a sharp increase of 1882.6% in constructed water storage areas for human uses. Diking, filling, impoundment and reclamation, which are all attributable to the economic development and urbanization associated with population increases, were the major factors that explained the gain and loss of wetlands. Additional factors affecting wetland losses and gains include sediment trapping by the hydropower system, which reduces supply to the estuary and erodes wetlands, and sediment trapping by the jetties, spur dikes, and diversion bulwark associated with a navigation channel deepening project, which has the converse effect, increasing saltmarsh wetland area at

  8. Detecting wetland changes in Shanghai, China using FORMOSAT and Landsat TM imagery

    Science.gov (United States)

    Tian, Bo; Zhou, Yun-Xuan; Thom, Ronald M.; Diefenderfer, Heida L.; Yuan, Qing

    2015-10-01

    Understanding the state of wetland ecosystems and their changes at the national and local levels is critical for wetland conservation, management, decision-making, and policy development practices. This study analyzed the wetlands in Shanghai, a province-level city, using remote sensing, image processing, and geographic information systems (GIS) techniques based on the Chinese national wetland inventory procedure and standards. FORMOSAT imagery acquired in 2012 and Navy nautical charts of the Yangtze estuarine area were used in conjunction with object-oriented segmentation, expert interpretation, and field validation to determine wetland status. Landsat imagery from 1985, 1995, 2000, 2003 and 2013 as well as social-economic data collected from 1985 to 2013 were used to further assess wetland changes. In 2013, Shanghai contained 376970.6 ha of wetlands, and 78.8% of all wetlands were in marine or estuarine systems. Estuarine waters comprised the single largest wetland category. Between the first national wetland inventory in 2003 and the second national wetland inventory in 2013, Shanghai lost 50519.1 ha of wetlands, amounting to a mean annual loss rate of 1.2% or an 11.8% loss over the decade. Declines were proportionately higher in marine and estuarine wetlands, with an annual loss of 1.8%, while there was a sharp increase of 1882.6% in constructed water storage areas for human uses. Diking, filling, impoundment and reclamation, which are all attributable to the economic development and urbanization associated with population increases, were the major factors that explained the gain and loss of wetlands. Additional factors affecting wetland losses and gains include sediment trapping by the hydropower system, which reduces supply to the estuary and erodes wetlands, and sediment trapping by the jetties, spur dikes, and diversion bulwark associated with a navigation channel deepening project, which has the converse effect, increasing saltmarsh wetland area at

  9. Wonderful Wetlands: An Environmental Education Curriculum Guide for Wetlands.

    Science.gov (United States)

    King County Parks Div., Redmond, WA.

    This curriculum guide was designed to give teachers, students, and society a better understanding of wetlands in the hope that they learn why wetlands should be valued and preserved. It explores what is meant by wetlands, functions and values of wetlands, wetland activities, and wetland offerings which benefit animal and plant life, recreation,…

  10. Geochemical and diatom records of recent changes in depositional environment of a tropical wetland, central west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Pande, A.; Nayak, G.N.; Prasad, V.; PrakashBabu, C

    Two mudflat sediment cores collected from a sub-channel (S-61) and the main channel (S-60) of a tropical wetland, along central west coast of India, were investigated for recent changes in depositional environment using geochemical (sediment grain...

  11. Development of a "Hydrologic Equivalent Wetland" Concept for Modeling Cumulative Effects of Wetlands on Watershed Hydrology

    Science.gov (United States)

    Wang, X.; Liu, T.; Li, R.; Yang, X.; Duan, L.; Luo, Y.

    2012-12-01

    Wetlands are one of the most important watershed microtopographic features that affect, in combination rather than individually, hydrologic processes (e.g., routing) and the fate and transport of constituents (e.g., sediment and nutrients). Efforts to conserve existing wetlands and/or to restore lost wetlands require that watershed-level effects of wetlands on water quantity and water quality be quantified. Because monitoring approaches are usually cost or logistics prohibitive at watershed scale, distributed watershed models, such as the Soil and Water Assessment Tool (SWAT), can be a best resort if wetlands can be appropriately represented in the models. However, the exact method that should be used to incorporate wetlands into hydrologic models is the subject of much disagreement in the literature. In addition, there is a serious lack of information about how to model wetland conservation-restoration effects using such kind of integrated modeling approach. The objectives of this study were to: 1) develop a "hydrologic equivalent wetland" (HEW) concept; and 2) demonstrate how to use the HEW concept in SWAT to assess effects of wetland restoration within the Broughton's Creek watershed located in southwestern Manitoba of Canada, and of wetland conservation within the upper portion of the Otter Tail River watershed located in northwestern Minnesota of the United States. The HEWs were defined in terms of six calibrated parameters: the fraction of the subbasin area that drains into wetlands (WET_FR), the volume of water stored in the wetlands when filled to their normal water level (WET_NVOL), the volume of water stored in the wetlands when filled to their maximum water level (WET_MXVOL), the longest tributary channel length in the subbasin (CH_L1), Manning's n value for the tributary channels (CH_N1), and Manning's n value for the main channel (CH_N2). The results indicated that the HEW concept allows the nonlinear functional relations between watershed processes

  12. Factors that influence the hydrologic recovery of wetlands in the Northern Tampa Bay area, Florida

    Science.gov (United States)

    Metz, P.A.

    2011-01-01

    Reductions in groundwater withdrawals from Northern Tampa Bay well fields were initiated in mid-2002 to improve the hydrologic condition of wetlands in these areas by allowing surface and groundwater levels to recover to previously higher levels. Following these reductions, water levels at some long-term wetland monitoring sites have recovered, while others have not recovered as expected. To understand why water levels for some wetlands have not increased, nine wetlands with varying impacts from well field pumping were examined based on four factors known to influence the hydrologic condition of wetlands in west-central Florida. These factors are the level of the potentiometric surface of the Upper Floridan aquifer underlying the wetland, recent karst activity near and beneath the wetland, permeability of the underlying sediments, and the topographic position of the wetland in the landscape.

  13. Bathymetry of the Levant basin: interaction of salt-tectonics and surficial mass movements

    Science.gov (United States)

    Gvirtzman, Zohar; Reshef, Moshe; Buch-Leviatan, Orna; Groves-Gidney, Gavrielle; Karcz, Zvi; Makovsky, Yizhaq; Ben-Avraham, Zvi

    2015-04-01

    A new high resolution bathymetric map of the Levant Basin between Israel and the Eratosthenes Seamount reveals previously undetected folds, faults and channels. The map facilitates a regional map-view analysis of structures that were previously examined only in cross section. The systematic mapping of morpho-structural elements in the entire basin is followed by a kinematic interpretation that distinguished between two main processes sculpting the seabed from bottom and top: salt tectonics and sediment transport. We show that the contractional domain related to salt tectonics is far more complex than previously thought. Ridges, previously interpreted as contractional folds are, in fact, surficial undulations of the seabed reminiscent of sediment waves. Moreover, other folds previously interpreted as downdip contraction of the westward gliding Plio-Quaternary section are, in some parts of the basin, caused by updip climbing of this section eastwards as a result of the regional pattern of salt flow away from the Nile Cone. In the context of sediment transport, we show that the northern Sinai continental slope is covered by a dense net of turbidite channels, whereas the Levant slope has no channels at all. Particularly interesting is the Levant Turbidite Channel, described and named here for the first time. This feature begins at the southeastern corner of the Mediterranean at water depths of ~1100 m, continues along the valley between the Sinai and Levant slopes, and reaches the deepest part of the basin, in water depths of ~2500 m, northeast of the Eratosthenes seamount. However, this prominent feature cannot be explained by the current drainage, consisting of two minor rivers that enter the basin at that point, and thus most likely reflects periods of wetter climate and/or lower sea-level, when these rivers were more active and possibly connected to the submarine channel system.

  14. Vegetation community composition in wetlands created following oil sand mining in Alberta, Canada.

    Science.gov (United States)

    Roy, Marie-Claude; Foote, Lee; Ciborowski, Jan J H

    2016-05-01

    Reclaiming wetlands following open pit mining for industrial oil sand extraction is challenging due to the physical and chemical conditions of the post-mined landscape. The aim of our study was to examine and compare the influence of oil sands process water (OSPW) and material (fine fluid tails or FFT) on the plant community composition of created wetlands. Compared to created-unamended and natural wetlands, the created wetlands amended with OSPW and/or FFT (created-tailings wetlands) had significantly higher water salinity, conductivity, dissolved oxygen concentration and lower oxidative-reductive potential. Water chemistry parameters of created-unamended did not differ significantly from those of natural wetlands. The sediment of created wetlands had significantly less moisture, total nitrogen, and organic content than the natural wetlands. The application of OSPW/FFT in created wetlands will likely lead to initial vegetation composition atypical of natural regional wetlands. For the objective of reclaiming vegetation composition to the status of natural regional wetlands, unamended wetlands were the best reclamation option, based on the physical and chemical parameters measured. Despite being the favored reclamation option, created-unamended wetlands' physical and chemical characteristics remain atypical of natural wetlands. Most significantly, the basin morphometry of created wetlands was significantly different from that of naturally-formed wetlands in the region, and this appears to partly explain difference in vegetation composition. We also demonstrate that species richness alone is not a useful measure in wetland monitoring. Instead, plant community composition is a better indicator of wetland conditions. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Percent Wetland Cover

    Data.gov (United States)

    U.S. Environmental Protection Agency — Wetlands act as filters, removing or diminishing the amount of pollutants that enter surface water. Higher values for percent of wetland cover (WETLNDSPCT) may be...

  16. Percent Wetland Cover (Future)

    Data.gov (United States)

    U.S. Environmental Protection Agency — Wetlands act as filters, removing or diminishing the amount of pollutants that enter surface water. Higher values for percent of wetland cover (WETLNDSPCT) may be...

  17. VSWI Wetlands Advisory Layer

    Data.gov (United States)

    Vermont Center for Geographic Information — This dataset represents the DEC Wetlands Program's Advisory layer. This layer makes the most up-to-date, non-jurisdictional, wetlands mapping avaiable to the public...

  18. Why are wetlands important?

    Science.gov (United States)

    Wetlands are among the most productive ecosystems in the world, comparable to rain forests and coral reefs. An immense variety of species of microbes, plants, insects, amphibians, reptiles, birds, fish, and mammals can be part of a wetland ecosystem.

  19. Artesian Wetlands Survey

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Artesian Wetlands Survey includes data on the wetlands in the San Luis Valley in Colorado. Data recorded includes location, area of influence, area inundated,...

  20. Wetland Program Pilot Grants

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Wetland Grant Database (WGD) houses grant data for Wetland Program Development Grants (created by EPA in 1990 under the Clean Water Act Section 104(b)(3)...

  1. Improving wetland mapping techniques

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Mapping wetland extent, structure and invasives using radar imagery. Acquiring optical, thermal, LIDAR, and RADAR images and analysis for improved wetland mapping,...

  2. Modoc wetlands study plan

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Study plan for Modoc Wetlands Study: An assessment of the probable responses of selected wildlife to wetlands management on the Modoc National Forest.

  3. Wetland eco-engineering: Measuring and modeling feedbacks of oxidation processes between plants and clay-rich material

    NARCIS (Netherlands)

    Saaltink, R.; Dekker, S.C.; Griffioen, J.; Wassen, M.J.

    2016-01-01

    Interest is growing in using soft sediment as a foundation in eco-engineering projects. Wetland construction in the Dutch lake Markermeer is an example: here, dredging some of the clay-rich lake-bed sediment and using it to construct wetland will soon begin. Natural processes will be utilized during

  4. Wetland eco-engineering: measuring and modeling feedbacks of oxidation processes between plants and clay-rich material

    NARCIS (Netherlands)

    Saaltink, R.M.; Dekker, S.C.; Griffioen, J.; Wassen, M.J.

    2016-01-01

    Interest is growing in using soft sediment as a foundation in eco-engineering projects. Wetland construction in the Dutch lake Markermeer is an example: here, dredging some of the clay-rich lake-bed sediment and using it to construct wetland will soon begin. Natural processes will be utilized during

  5. Climatic change and permafrost. Record from surficial deposits

    Science.gov (United States)

    Carter, L. David

    1990-01-01

    The physical and chemical characteristics of surficial deposits and the floral and faunal remains they contain provide information that is useful for interpreting both paleoclimatic and past permafrost conditions. Surficial deposits thus provide a record of climatic change and permafrost history. This record suggests that initiation of permafrost in lowland areas of the Southern Arctic Archipelago and continents of the northern hemisphere may have occurred about 2,400,000 years ago during the pronounced cooling that led to the first major glaciation of late Cenozoic time. Since then, climate has been relatively cold but cyclically variable, characterized by the growth and shrinkage of large, continental ice sheets. Permafrost has expanded and contracted in response to these climatic changes, and we can expect the present permafrost conditions to change in response to future climatic changes. To predict the response of permafrost and the landscape to future climatic change we should: (1) Define relations between climate and the modern landscape; (2) establish long-term records of past climatic change and landscape response; and (3) determine the paleoenvironments of past warm periods as possible analogs for future global warming.

  6. Wetlands and infectious diseases

    OpenAIRE

    Robert H. Zimmerman

    2001-01-01

    There is a historical association between wetlands and infectious disease that has led to the modification of wetlands to prevent disease. At the same time there has been the development of water resources projects that increase the risk of disease. The demand for more water development projects and the increased pressure to make natural wetlands economically beneficial creates the need for an ecological approach to wetland management and health assessment. The environmental and health intera...

  7. Redeeming the Weeping Wetland

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Renowned as the"Kidneys of the Earth,"wetlands are one of the three major ecosystems of the planet,along with forests and seas.With 10 percent of the world’s wetlands,China ranks number one in terms of the area of wetlands in Asia,and fourth in the world.China’s wetlands are abundant in type(containing all-natural and man-made types listed in the Convention

  8. Surficial deposits on salt diapirs (Zagros Mountains and Persian Gulf Platform, Iran): Characterization, evolution, erosion and the influence on landscape morphology

    Science.gov (United States)

    Bruthans, Jiří; Filippi, Michal; Asadi, Naser; Zare, Mohammad; Šlechta, Stanislav; Churáčková, Zdenka

    2009-06-01

    The surfaces of salt diapirs in the Zagros Mountains are mostly covered by surficial deposits, which significantly affect erosion rates, salt karst evolution, land use and the density of the vegetation cover. Eleven salt diapirs were selected for the study of surficial deposits in order to cover variability in the geology, morphology and climate in a majority of the diapirs in the Zagros Mountains and Persian Gulf Platform. The chemical and mineralogical compositions of 80 selected samples were studied mainly by X-ray powder diffraction and X-ray fluorescence. Changes in salinity along selected vertical profiles were studied together with the halite and gypsum distribution. The subaerial residuum formed from minerals and rock detritus released from the dissolved rock salt is by far the most abundant material on the diapirs. Fluvial sediments derived from this type of residuum are the second most common deposits found, while submarine residuum and marine sediments have only local importance. The mineralogical/chemical composition of surficial deposits varies amongst the three end members: evaporite minerals (gypsum/anhydrite and minor halite), carbonates (dolomite and calcite) and silicates-oxides (mainly quartz, phyllosilicates, and hematite). Based on infiltration tests on different types of surficial deposits, most of the rainwater will infiltrate, while overland flow predominates on rock salt exposures. Recharge concentration and thick accumulations of fine sediment support relatively rich vegetation cover in some places and even enable local agricultural activity. The source material, diapir relief, climatic conditions and vegetation cover were found to be the main factors affecting the development and erosion of surficial deposits. A difference was found in residuum type and landscape morphology between the relatively humid NW part of the studied area and the arid Persian Gulf coast: In the NW, the medium and thick residuum seems to be stable under current

  9. Wetlands in China

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Wetlands are shallow marine waters and wet areas in cluding rivers, lakes and marshes. According to scientists, even reservoirs and paddy fields fall into the category. Wetlands are classified into over 40 types but accounts for only 6% of the earth's total land area. Human beings inhabit by water and grass because wetlands provide us with water and wet soil.

  10. Simulated wetland conservation-restoration effects on water quantity and quality at watershed scale.

    Science.gov (United States)

    Wang, Xixi; Shang, Shiyou; Qu, Zhongyi; Liu, Tingxi; Melesse, Assefa M; Yang, Wanhong

    2010-07-01

    Wetlands are one of the most important watershed microtopographic features that affect hydrologic processes (e.g., routing) and the fate and transport of constituents (e.g., sediment and nutrients). Efforts to conserve existing wetlands and/or to restore lost wetlands require that watershed-level effects of wetlands on water quantity and water quality be quantified. Because monitoring approaches are usually cost or logistics prohibitive at watershed scale, distributed watershed models such as the Soil and Water Assessment Tool (SWAT), enhanced by the hydrologic equivalent wetland (HEW) concept developed by Wang [Wang, X., Yang, W., Melesse, A.M., 2008. Using hydrologic equivalent wetland concept within SWAT to estimate streamflow in watersheds with numerous wetlands. Trans. ASABE 51 (1), 55-72.], can be a best resort. However, there is a serious lack of information about simulated effects using this kind of integrated modeling approach. The objective of this study was to use the HEW concept in SWAT to assess effects of wetland restoration within the Broughton's Creek watershed located in southwestern Manitoba, and of wetland conservation within the upper portion of the Otter Tail River watershed located in northwestern Minnesota. The results indicated that the HEW concept allows the nonlinear functional relations between watershed processes and wetland characteristics (e.g., size and morphology) to be accurately represented in the models. The loss of the first 10-20% of the wetlands in the Minnesota study area would drastically increase the peak discharge and loadings of sediment, total phosphorus (TP), and total nitrogen (TN). On the other hand, the justifiable reductions of the peak discharge and loadings of sediment, TP, and TN in the Manitoba study area may require that 50-80% of the lost wetlands be restored. Further, the comparison between the predicted restoration and conservation effects revealed that wetland conservation seems to deserve a higher priority

  11. Sediment Texture Units of the Sea Floor from Nahant to Northern Cape Cod Bay, Massachusetts (NAH_CCB_sedcover polygon shapefile, Geographic, WGS84)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data are qualitatively derived interpretive polygon shapefiles and selected source raster data defining surficial geology, sediment type and distribution, and...

  12. Sediment Texture Units of the Sea Floor from Nahant to Northern Cape Cod Bay, Massachusetts (NAH_CCB_sedcover polygon shapefile, Geographic, WGS84)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data are qualitatively derived interpretive polygon shapefiles and selected source raster data defining surficial geology, sediment type and distribution, and...

  13. Interannual changes in seafloor surficial geology at an artificial reef site on the inner continental shelf

    Science.gov (United States)

    Raineault, Nicole A.; Trembanis, Arthur C.; Miller, Douglas C.; Capone, Vince

    2013-04-01

    The influence of reef structures on seafloor surface sediments has implications for marine spatial planning and coastal development, including use of the coastal zone for offshore wind energy. We present results of interannual changes in seafloor surficial geology at the Redbird artificial reef site, located on the continental shelf offshore of Delaware Bay. The Redbird reef is composed of NYC subway cars, barges, tugboats, and other sunken objects. Since objects were added sporadically between 1996 and 2009, the survey area acts as a natural laboratory to study the evolution of the surrounding seafloor at a structural reef habitat through time. Annual side-scan surveys from 2008 through 2011, and one bathymetric survey in 2010 provide information about surface geology and morphology. Local wave and current data for this time period were analyzed to determine the main morphological agents. Automated backscatter segmentation show that three bottom types dominate and that these large-scale (>10 m) surface sediment patterns persist from year to year. Grab samples reveal that the bottom types are silty sand with clay and sandy gravel. Clear sediment and biological patterns emerged revealing the influence of the objects on the seafloor. Comet-shaped moats of sandy gravel surround single objects and grow to form large-scale coalesced patches around groups of objects. Alignment of sediment patches suggests the periodic hydrodynamic influence of seasonal storms. The abundance and diversity of organisms increases with decreasing clay/silt content. Evidence of scour includes the removal of fine sediments, the formation of moats 1-30 m in diameter and 0.5-1 m deep around the reef objects, and the >1 m settling of objects into the seafloor. Data suggest subway cars reached equilibrium with the environment in 6-7 years, but that larger objects or clusters of objects take a longer time to equilibrate and have farther-reaching effects. Knowledge of local wave and current climate

  14. Contribution of Plant Litters to Sediments Organic Matter in Jiulong River Estuary Wetland%九龙江口湿地植物凋落物对沉积物有机质赋存的贡献

    Institute of Scientific and Technical Information of China (English)

    罗专溪; 邱昭政; 王振红; 颜昌宙

    2013-01-01

    The purpose of this study was to characterize the decomposition process of different plant litters and its controlling factors, and to quantify the different contribution rates to sediments organic matter throughout the decomposition of different plant litters. Results showed that the decomposition rates of plant litters buried at medium tidal level were 0.655 a-1 for mangrove and 1.723 a-1 for Spartina, which were greater than those with 0. 651 a-1 for mangrove and 1. 586 a-1 for Spartina at high tidal level. The reduction of carbon concentration in plant litters at high tidal level was lower than that at medium tidal level, while the increment of nitrogen and sulfur concentrations in plant litters at high tidal level was greater than those at medium tidal. And the isotope abundance of carbon ( δ13C) in plant litters at medium tidal level reduced much more significantly than that at high tidal level. The contribution rates of plant litters carbon to sediments organic matter differed among tidal levels, plant species and decomposition duration. Specifically, the decomposition of mangrove litters contributed 5. 96% to the sediment organic matter at medium tidal level, which was greater than that (3. 03% ) at high tidal level. Similarly, the decomposition of Spartina litters contributed 14. 81% to the sediment organic matter at medium tidal level, which was also greater than that ( 13. 97% ) at high tidal level. The contribution of the decomposition of Spartina litters organic matter ( average with 14. 39% ) was greater than that of mangrove litters (4. 50% ). The decomposition of plant litters requires a long process. The contribution of plant litters to sediments organic matter throughout one year decomposition was lower than that in complete decomposition, in particular, mangrove litters. Our study showed that the quantitative differences in plant litters-derived sediment organic matter would improve the proper estimation of the contribution of litters to wetland

  15. 胶州湾湿地海域水体和表层沉积物环境质量评价%Environmental aualitv assessment of water body and surface sediment in the sea area of Jiaozhou Bay wetland

    Institute of Scientific and Technical Information of China (English)

    马洪瑞; 陈聚法; 崔毅; 赵俊; 杨风

    2011-01-01

    Based on the investigation data from 48 sampling stations in the sea area of Jiaozhou Bay wetland in 2009, and by using Nemerow index, eutrophication index ( El) , and Hakanson potential ecological risk index, an assessment was conducted on the environmental quality of water body and surface sediment in the sea area. According to the assessment on the 16 indicators including pH, dissolved oxygen ( DO) , dissolved inorganic nitrogen ( DIN) , dissolved inorganic phosphorous (DIP) , chemical oxygen demand (CODMn) , petroleum hydrocarbons, Cu, Zn, Pb, Cd, Hg, As, hexachlorocyolohexane (HCH) , dichlorodiphenyltrichloroethane (DDT) , conform, and faecal coli-form, the water quality was at moderate and serious pollution level in the tidal reach of Dagu River, at slight and moderate pollution level in the intertidal zone, and at slight pollution level in the shallow sea. The eutrophication level differed markedly with the regions, being very serious in the tidal reach of Dagu River (El value 58. 13-327. 89), serious in the intertidal zone (El value 1. 34-19. 96) , and slight in the shallow sea (El value 0. 65-2. 10). The surface sediments in the sea area were basically at slight pollution level. The sediment quality was at slight pollution level in the tidal reach of Dagu River, at slight and moderate pollution level in the intertidal zone, and at cleaner and slight pollution level in the shallow sea. The pollution parameter ( C/ ) and contamination index (Cd) of the heavy metals in the surface sediments were low, suggesting that the pollution de-gree was at a lower level. The Cu and Zn were the primary pollution factors in the sediments. The potential ecological risk parameter (£,') and risk index (RI) of the heavy metals in the surface sediments were lower, indicating a slight ecological risk of heavy metals pollution.%基于2009年对胶州湾湿地48个站点的调查数据,采用内梅罗(Nemerow)指数、富营养指数(EI)和Hakanson潜在生态危害指数法对

  16. Investigating Hydrogeologic Controls on Sandhill Wetlands in Covered Karst with 2D Resistivity and Ground Penetrating Radar

    Science.gov (United States)

    Downs, C. M.; Nowicki, R. S.; Rains, M. C.; Kruse, S.

    2015-12-01

    In west-central Florida, wetland and lake distribution is strongly controlled by karst landforms. Sandhill wetlands and lakes are sand-filled upland basins whose water levels are groundwater driven. Lake dimensions only reach wetland edges during extreme precipitation events. Current wetland classification schemes are inappropriate for identifying sandhill wetlands due to their unique hydrologic regime and ecologic expression. As a result, it is difficult to determine whether or not a wetland is impacted by groundwater pumping, development, and climate change. A better understanding of subsurface structures and how they control the hydrologic regime is necessary for development of an identification and monitoring protocol. Long-term studies record vegetation diversity and distribution, shallow ground water levels and surface water levels. The overall goals are to determine the hydrologic controls (groundwater, seepage, surface water inputs). Most recently a series of geophysical surveys was conducted at select sites in Hernando and Pasco County, Florida. Electrical resistivity and ground penetrating radar were employed to image sand-filled basins and the top of the limestone bedrock and stratigraphy of wetland slopes, respectively. The deepest extent of these sand-filled basins is generally reflected in topography as shallow depressions. Resistivity along inundated wetlands suggests the pools are surface expressions of the surficial aquifer. However, possible breaches in confining clay layers beneath topographic highs between depressions are seen in resistivity profiles as conductive anomalies and in GPR as interruptions in otherwise continuous horizons. These data occur at sites where unconfined and confined water levels are in agreement, suggesting communication between shallow and deep groundwater. Wetland plants are observed outside the historic wetland boundary at many sites, GPR profiles show near-surface layers dipping towards the wetlands at a shallower

  17. The importance of hydrology in restoration of bottomland hardwood wetland functions

    Science.gov (United States)

    Hunter, R.G.; Faulkner, S.P.; Gibson, K.A.

    2008-01-01

    Bottomland hardwood (BLH) forests have important biogeochemical functions and it is well known that certain structural components, including pulsed hydrology, hydric soils, and hydrophytic vegetation, enhance these functions. It is unclear, however, how functions of restored BLH wetlands compare to mature, undisturbed wetlands. We measured a suite of structural and functional attributes in replicated natural BLH wetlands (NAT), restored BLH wetlands with hydrology re-established (RWH), and restored BLH wetlands without hydrology re-established (RWOH) in this study. Trees were replanted in all restored wetlands at least four years prior to the study and those wetlands with hydrology re-established had flashboard risers placed in drainage ditches to allow seasonal surface flooding. Vegetation, soils, and selected biogeochemical functions were characterized at each site. There was a marked difference in woody vegetation among the wetlands that was due primarily to site age. There was also a difference in herbaceous vegetation among the restored sites that may have been related to differences in age or hydrology. Water table fluctuations of the RWH wetlands were comparable to those of the NAT wetlands. Thus, placing flashboard risers in existing drainage ditches, along with proper management, can produce a hydroperiod that is similar to that of a relatively undisturbed BLH. Average length of saturation within the upper 15 cm of soils was 37, 104, and 97 days for RWOH, RWH, and NAT, respectively. Soil moisture, denitrification potential, and soluble organic carbon concentrations differed among wetland sites, but soil carbon and nitrogen concentrations, heterotrophic microbial activity, and readily mineralizable carbon concentrations did not. Significant linear relationships were also found between soil moisture and heterotrophic microbial activity, readily mineralizable carbon, and soluble organic carbon. In addition, sedimentation rates were higher in NAT and RWH

  18. Surficial geologic map of the Walden 30' x 60' quadrangle, Jackson, Larimer, and Routt counties, Colorado

    Science.gov (United States)

    Madole, R.F.

    1991-01-01

    This map is one of a series of four 30' x 60' surficial geologic maps (1:100,000 scale) intended to provide basic geologic information for planning for energy resource development and growth in northwestern Colorado. An effort is made to characterize all surficial materials, regardless of origin. Hence, residuum is given much more emphasis than is customary, and this results in several departures from conventional geologic maps: bedrock geology is deemphasized; the part of the map symbol denoting geologic age is omitted for surficial units because all surficial units shown are believed to be of Quaternary age; and faults are not shown because none in this map area was observed to displace surficial materials.

  19. High rates of denitrification and nitrate removal in cold seep sediments

    OpenAIRE

    Bowles, Marshall; Joye, Samantha

    2010-01-01

    We measured denitrification and nitrate removal rates in cold seep sediments from the Gulf of Mexico. Heterotrophic potential denitrification rates were assayed in time-series incubations. Surficial sediments inhabited by Beggiatoa exhibited higher heterotrophic potential denitrification rates (32 μ N reduced day−1) than did deeper sediments (11 μ N reduced day−1). Nitrate removal rates were high in both sediment horizons. These nitrate removal rates translate into rapid turnover times (...

  20. Urea transformation of wetland microbial communities.

    Science.gov (United States)

    Thorén, Ann-Karin

    2007-02-01

    Transformation of urea to ammonium is an important link in the nitrogen cycle in soil and water. Although microbial nitrogen transformations, such as nitrification and denitrification, are well studied in freshwater sediment and epiphytic biofilm in shallow waters, information about urea transformation in these environments is scarce. In this study, urea transformation of sedimentary, planktonic, and epiphytic microbial communities was quantified and urea transformation of epiphytic biofilms associated with three different common wetland macrophyte species is compared. The microbial communities were collected from a constructed wetland in October 2002 and urea transformation was quantified in the laboratory at in situ temperature (12 degrees C) with the use of the 14C-urea tracer method, which measures the release of 14CO2 as a direct result of urease activity. It was found that the urea transformation was 100 times higher in sediment (12-22 mmol urea-N m(-2) day(-1)) compared with the epiphytic activity on the surfaces of the submerged plant Elodea canadensis (0.1-0.2 mmol urea-N m(-2) day(-1)). The epiphytic activity of leaves of Typha latifolia was lower (0.001-0.03 mmol urea-N m(-2) day(-1)), while urea transformation was negligible in the water column and on the submerged leaves of the emergent plant Phragmites australis. However, because this wetland was dominated by dense beds of the submerged macrophyte E. canadensis, this plant provided a large surface area for epiphytic microbial activity-in the range of 23-33 m2 of plant surfaces per square meter of wetland. Thus, in the wetland system scale at the existing plant distribution and density, the submerged plant community had the potential to transform 2-7 mmol urea-N m(-2) day(-1) and was in the same magnitude as the urea transformation in the sediment.

  1. Freshwater Wetlands: A Citizen's Primer.

    Science.gov (United States)

    Catskill Center for Conservation and Development, Inc., Hobart, NY.

    The purpose of this "primer" for the general public is to describe the general characteristics of wetlands and how wetland alteration adversely affects the well-being of humans. Particular emphasis is placed on wetlands in New York State and the northeast. Topics discussed include wetland values, destruction of wetlands, the costs of wetland…

  2. Freshwater Wetlands: A Citizen's Primer.

    Science.gov (United States)

    Catskill Center for Conservation and Development, Inc., Hobart, NY.

    The purpose of this "primer" for the general public is to describe the general characteristics of wetlands and how wetland alteration adversely affects the well-being of humans. Particular emphasis is placed on wetlands in New York State and the northeast. Topics discussed include wetland values, destruction of wetlands, the costs of…

  3. Freshwater Wetlands: A Citizen's Primer.

    Science.gov (United States)

    Catskill Center for Conservation and Development, Inc., Hobart, NY.

    The purpose of this "primer" for the general public is to describe the general characteristics of wetlands and how wetland alteration adversely affects the well-being of humans. Particular emphasis is placed on wetlands in New York State and the northeast. Topics discussed include wetland values, destruction of wetlands, the costs of…

  4. ROLE OF CONSTRUCTED WETLANDS IN NUTRIENT STRIPPING

    Institute of Scientific and Technical Information of China (English)

    Khan A; Zubair M; Ali R

    2005-01-01

    A number of research programs have been established to evaluate potential applications of constructed wetlands in Western Australia. These constructed wetlands are known not only for their nutrient removal capability, but also their role in habitat creation, urban landscaping and water quality and environmental health. They play an important role in the reduction of nutrients, particularly phosphorous, from entering the waterways.This paper reports on the improvement of water quality in the Peel Main Drain before its disposal into the Peel Estuary, Perth, Western Australia. The nitrogen to phosphorous (N:P) ratio was below the critical limit during summer (dry spell) and the system was limited by nitrogen. The concentration of phosphorus was high in summer and low in winter due to increased availability of dissolved oxygen in winter.A wetland was proposed to improve the water quality in the Peel Main Drain using vegetation and substrate. The hydrologic effectiveness was found to be 78% for a detention time of 30 hours. It is expected that the maximum nitrogen removal efficiency of the constructed wetland will be 80% with an estimated efficiency of 40% in the first year and 60-80% in the subsequent years. For phosphorous it is expected that the constructed wetland will be effective in removing filterable reactive phosphorous. Traditional sediment remediation techniques have been found unsuitable for the long term binding of the phosphorous therefore the use of Phoslock TM is recommended.

  5. Redox Transformations of Mercury in Wetlands

    Science.gov (United States)

    Amyot, M.

    2007-12-01

    Wetlands are valued for their high biodiversity and for their ecosystem services. However, we still have a poor understanding of their role in the redox transformation of contaminants such as mercury. We first propose a brief overview of past studies conducted on wetlands from different latitudes. In most instances, photochemical processes are determinant in the upper portion of the water column. At the sediment/water interface, evidence is currently supporting a significant contribution of bacterial communities, as promoters of Hg(II) reduction, particularly in the presence of anoxia. A multi-year study was recently conducted on Hg redox cycling in a fluvial wetland of the St. Lawrence River, where wetland restoration could have unintended consequences. In addition to photochemistry and bacterial reduction, Hg redox cycling was affected by epiphytes living on macrophytes, through adsorption/absorption processes. Redox studies such as this one have been historically seen as having implication for water/air flux studies, since Hg(0) is volatile. We here also discuss the potential bioavailability of Hg(0) towards bacteria. An emerging axis of our wetland research effort deals with beaver dams, which are in expansion and shown to produce high levels of methylHg

  6. Accumulation rates of airborne heavy metals in wetlands

    Science.gov (United States)

    Souch, C.J.; Filippelli, G.M.; Dollar, N.; Perkins, S.; Mastalerz, Maria

    2002-01-01

    Accumulation rates of heavy metals (Cd, Cr, Cu, Mn, Pb, and Zn) retained in wetland sediments in northwest Indiana-downwind of the Chicago-Gary-Hammond industrial area-are quantified to assess anthropogenic influences on atmospheric fluxes. Metal concentrations for 22 sediment cores are determined by ICP-AES after ashing and strong acid extraction. Relations between organic content and metal concentrations at depth are used to separate natural and anthropogenic sources. Accumulation rates over the lifetime of the wetlands (???4500 years) have averaged 0.2 (Cd), 1.4 (Cu), 1.7 (Cr), 13.4 (Mn), 4.8 (Pb), and 18.7 (Zn) mg m-2 y-1. Rates for the last 100 years have increased on average by factors of 6 (Cd), 8 (Cu), 10 (Mn), 15 (Pb), and 30 (Zn), remaining effectively constant for Cr. Where the wetlands have been drained, metals have been lost from the sediments, owing to changes in organic content and local hydrochemistry (exposure to acidic rainfall). Sediment-based accumulation rates at the undrained sites are higher, though generally consistent, with measured and modeled atmospheric fluxes documented by short-term studies conducted over the last three decades. The fraction of the total metals in the wetlands estimated to be of anthropogenic origin ranges from approximately 3% for Cr, up to approximately 35% for Pb, and 70% for Zn. This historic legacy of contamination must be considered in land management decisions, particularly when wetlands are drained.

  7. Mitigation of methane emissions from constructed farm wetlands.

    Science.gov (United States)

    Pangala, Sunitha R; Reay, David S; Heal, Kate V

    2010-01-01

    Constructed wetlands are increasingly used for water pollution treatment but may also be sources of the greenhouse gas CH(4). The effect of addition of two potential inhibitors of methanogenesis - iron ochre and gypsum - on net CH(4) emissions was investigated in a constructed wetland treating farm runoff in Scotland, UK. CH(4) fluxes from three 15-m(2) wetland plots were measured between January and July 2008 in large static chambers incorporating a tunable diode laser, with application of 5tonha(-1) ochre and gypsum in May. CH(4) fluxes were also measured from control and ochre- and gypsum-treated wetland sediment cores incubated at constant and varying temperature in the laboratory. Ochre addition suppressed CH(4) emissions by 64+/-13% in the field plot and >90% in laboratory incubations compared to controls. Gypsum application of 5tonha(-1) in the field and laboratory experiments had no effect on CH(4) emissions, but application of 10tonha(-1) to a sediment core reduced CH(4) emissions by 28%. Suppression of CH(4) emissions by ochre application to sediment cores also increased with temperature; the reduction relative to the control increased from 50% at 17.5 degrees C to >90% at 27.5 degrees C. No significant changes in N removal or pH and potentially-toxic metal content of sediments as the result of inhibitor application were detected in the wetland during the study.

  8. Specifically Designed Constructed Wetlands: A Novel Treatment Approach for Scrubber Wastewater

    Energy Technology Data Exchange (ETDEWEB)

    John H. Rodgers Jr; James W. Castle; Chris Arrington: Derek Eggert; Meg Iannacone

    2005-09-01

    A pilot-scale wetland treatment system was specifically designed and constructed at Clemson University to evaluate removal of mercury, selenium, and other constituents from flue gas desulfurization (FGD) wastewater. Specific objectives of this research were: (1) to measure performance of a pilot-scale constructed wetland treatment system in terms of decreases in targeted constituents (Hg, Se and As) in the FGD wastewater from inflow to outflow; (2) to determine how the observed performance is achieved (both reactions and rates); and (3) to measure performance in terms of decreased bioavailability of these elements (i.e. toxicity of sediments in constructed wetlands and toxicity of outflow waters from the treatment system). Performance of the pilot-scale constructed wetland treatment systems was assessed using two criteria: anticipated NPDES permit levels and toxicity evaluations using two sentinel toxicity-testing organisms (Ceriodaphnia dubia and Pimephales promelas). These systems performed efficiently with varied inflow simulations of FGD wastewaters removing As, Hg, and Se concentrations below NPDES permit levels and reducing the toxicity of simulated FGD wastewater after treatment with the constructed wetland treatment systems. Sequential extraction procedures indicated that these elements (As, Hg, and Se) were bound to residual phases within sediments of these systems, which should limit their bioavailability to aquatic biota. Sediments collected from constructed wetland treatment systems were tested to observe toxicity to Hyalella azteca or Chironomus tetans. Complete survival (100%) was observed for H. azteca in all cells of the constructed wetland treatment system and C. tentans had an average of 91% survival over the three treatment cells containing sediments. Survival and growth of H. azteca and C. tentans did not differ significantly between sediments from the constructed wetland treatment system and controls. Since the sediments of the constructed

  9. Colorado wetlands initiative : 1997-2000 : Protecting Colorado's wetlands resource

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Colorado Wetlands Initiative is an endeavor to protect wetlands and wetland-dependent wildlife through the use of voluntary, incentive-based mechanisms. It is a...

  10. Phosphorus storage and mobilization in coastal Phragmites wetlands: Influence of local-scale hydrodynamics

    Science.gov (United States)

    Karstens, Svenja; Buczko, Uwe; Glatzel, Stephan

    2016-04-01

    Coastal Phragmites wetlands are at the interface between terrestrial and aquatic ecosystems and are of paramount importance for nutrient regulation. They can act both as sinks and sources for phosphorus, depending on environmental conditions, sediment properties as well as on antecedent nutrient loading and sorption capacity of the sediments. The Darss-Zingst Bodden Chain is a shallow lagoon system at the German Baltic Sea coast with a long eutrophication history. It is lined almost at its entire length by reed wetlands. In order to elucidate under which conditions these wetlands act as sources or sinks for phosphorus, in-situ data of chemo-physical characteristics of water and sediment samples were combined with hydrodynamic measurements and laboratory experiments. Small-scale basin structures within the wetland serve as sinks for fine-grained particles rich in phosphorus, iron, manganese and organic matter. Without turbulent mixing the bottom water and the sediment surface lack replenishment of oxygen. During stagnant periods with low water level, low turbulence and thus low-oxygen conditions phosphorus from the sediments is released. But the sediments are capable of becoming sinks again once oxygen is resupplied. A thin oxic sediment surface layer rich in iron and manganese adsorbs phosphorus quickly. We demonstrate that sediments in coastal Phragmites wetlands can serve both as sources and sinks of soluble reactive phosphorus on a very short time-scale, depending on local-scale hydrodynamics and the state of the oxic-anoxic sediment interface.

  11. Microbial Communities in Sediments across the Louisiana Continental Shelf

    Science.gov (United States)

    The Louisiana continental Shelf (LCS) is a dynamic system that receives discharges from two large rivers. It has a stratified water column that is mixed by winter storms, hypoxic bottom water from spring to fall, and a muddy seafloor with highly mixed surficial sediments. Spatia...

  12. 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...

  13. Interactions Between Wetlands and Tidal Inlets

    Science.gov (United States)

    2008-08-01

    Madre, TX), (3) fjord-type (e.g., Penobscot Bay , ME), and (4) tectonically created estuaries (e.g., San Francisco Bay , CA) (Pritchard 1967). This CHETN...small marsh island in San Francisco Bay , CA. Wolaver et al. (1988) measured suspended sediment flux of 827 g/m2/year into a marsh in North Inlet, SC...permanent or ephemeral inlets. Conversely, the development or construction of wetlands within an estuary reduces bay area and the tidal prism, which will

  14. Mitigation of two pyrethroid insecticides in a Mississippi Delta constructed wetland

    Science.gov (United States)

    Constructed wetlands are a suggested best management practice to help mitigate agricultural runoff before entering receiving aquatic ecosystems. A constructed wetland system (180 m x 30 m) comprised of a sediment retention basin and two treatment cells was used to determine fate and transport of sim...

  15. Uranium Redistribution Due to Water Table Fluctuations in Sandy Wetland Mesocosms

    Science.gov (United States)

    To understand better the fate and stability of immobilized uranium (U) in wetland sediments, and how intermittent dry periods affect U stability, we dosed saturated wetland mesocosms planted with Scirpus acutus with low levels of uranyl acetate for 4 months before imposing...

  16. The Spatial and Temporal Distribution and Pollution Assessment of Heavy Metals in the Surface Sediments of Hemu Wetland in Hangzhou%杭州和睦湿地表层沉积物重金属时空分布特征及污染评价

    Institute of Scientific and Technical Information of China (English)

    潘敏; 单监利; 姚武; 顾燕青; 巫阳; 朱维琴

    2014-01-01

    分析了杭州市和睦湿地表层沉积物重金属含量及分布特征,并运用污染指数法和 Hakanson潜在生态风险指数法对和睦湿地沉积物重金属进行了污染评价和生态风险评价.结果表明:空间分布上和睦湿地沉积物重金属以高Zn、高Ni含量和高Cu、Cr含量为主要特征;季节分布特征上以7月和1月的高Cu、Zn、Cr、Ni含量为主要特征;单项污染指数表明,和睦湿地沉积物中Cu、Zn、Cr、Ni在不同季节呈现一定的中、轻度单项污染,且以7月和1月的污染更甚,故应关注和睦湿地不同样点沉积物中Cu、Zn、Cr、Ni的季节性污染防控工作;综合污染指数评价表明,各样点在不同季节呈现中、轻度综合污染.Hakanson潜在综合生态风险评价指数(RI)表明,和睦湿地沉积物重金属的生态风险水平均达轻微风险等级,Hakanson潜在单项生态风险评价指数(Er)则表明,和睦湿地沉积物中主要的潜在生态风险因子为Cu与Cr ,故应重视和睦湿地沉积物重金属中Cu、Cr的潜在生态风险评价及管理.%This paper analyzed the content and seasonal distribution characteristics of heavy metals in the surface sediments of Hemu wetland ,Hangzhou ,and evaluated the pollution and ecological risk of these heavy metals by pollution index method and Hakanson potential ecological risk index method .The results show the enrichment of Zn ,Ni ,Cu and Cr in the surface sediments ,especially much higher in July and January .The single pollution index indicates the high content of Cu ,Zn ,Cr and Ni in the surface sediments presents moderate or mild single pollution in different seasons and the highest pollution level is in July and January ,which suggests the seasonal pollution prevention and control of Cu ,Zn ,Cr and Ni in the surface sediments of Hemu wetland needs to be paid more attention . The comprehensive pollution index evaluation reveals that each sample

  17. Dynamics in phosphorus retention in wetlands upstream of Delavan Lake, Wisconsin

    Science.gov (United States)

    Robertson, Dale M.; Elder, John F.; Goddard, Gerald L.; James, William F.

    2009-01-01

    A phosphorus budget was constructed for Delavan Lake Inlet, a perennial riverine wetland with submersed and floating aquatic vegetation in southeastern Wisconsin, to better understand the phosphorus dynamics in natural wetlands and the role of wetlands in lake-rehabilitation efforts. During the growing season, the inlet served as a net source of phosphorus, primarily due to the release of phosphorus from the sediments. More phosphorus was released from the sediments of the inlet (600 kg) than was input from the upstream watershed (460 kg). This release was caused by high pH associated with high photosynthetic activity. During the remainder of the year, the inlet served as a net sink for phosphorus, retaining 6% of die phosphorus input from the watershed. Over the entire year, this wetland was a net source of over 500 kg of phosphorus to downstream Delavan Lake. A constructed riverine wetland upstream of Delavan Lake Inlet demonstrated a similar periodic release of phosphorus. However, in this case, the summer release of phosphorus was less than that trapped during the remainder of the year. The constructed wetland served as a net sink for approximately 20% of the input phosphorus on an annual time scale. The role of existing and constructed wetlands as phosphorus traps is complex. Wetlands can act as a source or a sink for phosphorus depending on the ambient conditions in die wetland. Howa wetland fits into a rehabilitation plan depends upon its net retention efficiency and the importance of the periodic releases of phosphorus to downstream waters.

  18. Contaminants Investigation Bulletin: Environmental contaminants in sediments from oilfield produced water discharge points

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Trace element concentrations in sediment samples are shown in Table 2. Sediments from a wetland receiving oilfield produced water from the Arnell oil production site...

  19. Associated Fauna to Eichhornia crassipes in a Constructed Wetland for Aquaculture Effluent Treatment

    National Research Council Canada - National Science Library

    Lúcia Helena Sipaúba-Tavares; Bruno Scardoelli Truzzi; Ana Milstein; Aline Marcari Marques

    2017-01-01

    Water, sediment and associated fauna were studied in a water hyacinth ( ) stand of a constructed wetland, used for aquaculture effluent treatment in SE Brazil, in February-April (summer/rainy season...

  20. Secondary production in wetlands of the Lacreek National Wildlife refuge : 2002 progress report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Productivity of prairie wetlands is maintained through the natural wet/dry climatic cycles of the region. Periodic drying is required to oxidize sediments and...

  1. Environmental Contaminants Monitoring in Selected Wetlands of Wyoming: Biologically Active Elements Study

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Sediment, water and biota were collected from selected wetlands in Wyoming for the Biologically Active Elements (BAE) Study in 1988, 1989 and 1990 to identify...

  2. Secondary production in wetlands of the Lacreek National Wildlife refuge : 2003 progress report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Productivity of prairie wetlands is maintained through the natural wet/dry climatic cycles of the region. Periodic drying is required to oxidize sediments and...

  3. Wetlands & Deepwater Habitats - Montana Wetland and Riparian Framework - Map Service

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — The Montana Wetland and Riparian Framework represents the extent, type, and approximate location of wetlands, riparian areas, and deepwater habitats in Montana....

  4. A summary of the San Francisco tidal wetlands restoration series

    Directory of Open Access Journals (Sweden)

    Larry R. Brown

    2003-10-01

    Full Text Available The four topical articles of the Tidal Wetlands Restoration Series summarized and synthesized much of what is known about tidal wetlands and tidal wetland restoration in the San Francisco Estuary (hereafter “Estuary”. Despite a substantial amount of available information, major uncertainties remain. A major uncertainty with regard to fishes is the net benefit of restored tidal wetlands relative to other habitats for native fishes in different regions of the Estuary given the presence of numerous invasive alien species. With regard to organic carbon, a major uncertainty is the net benefit of land use change given uncertainty about the quantity and quality of different forms of organic carbon resulting from different land uses. A major challenge is determining the flux of organic carbon from open systems like tidal wetlands. Converting present land uses to tidal wetlands will almost certainly result in increased methylation of mercury at the local scale with associated accumulation of mercury within local food webs. However, it is unclear if such local accumulation is of concern for fish, wildlife or humans at the local scale or if cumulative effects at the regional scale will emerge. Based on available information it is expected that restored tidal wetlands will remain stable once constructed; however, there is uncertainty associated with the available data regarding the balance of sediment accretion, sea-level rise, and sediment erosion. There is also uncertainty regarding the cumulative effect of many tidal restoration projects on sediment supply. The conclusions of the articles highlight the need to adopt a regional and multidisciplinary approach to tidal wetland restoration in the Estuary. The Science Program of the CALFED effort provides an appropriate venue for addressing these issues.

  5. Geogenic distribution and baseline concentrations of Cu and Zn in surficial soil of Guiyang, China

    Institute of Scientific and Technical Information of China (English)

    WANG Ji; WANG Shijie; OUYANG Ziyuan; LI Ruiling

    2006-01-01

    This paper describes the environmentally geochemical characteristics of heavy metal pollu tants such as Cu and Zn in the surficial soil of Guiyang, the capital city of Guizhou Province. The baseline concentrations of heavy metals in soil and the geochemical norms have been established to distinguish natural or artificial influence on the environment. Using the statistically analytical methods, we have established the baseline of Cu in Guiyang ( 18.8 mg/kg) and the soil ( over 68.4 mg/kg) may suffer Cu contamination. The data of Zn are 46.3 mg/kg and 112.0 mg/kg. Geoaccumulation index analysis indicated that the surficial soil that has suffered non-pollution to mid-pollution of Cu accounts for 38%, 38%, and 22% for mid-pollution, and only 2% between mid-pollution to severe pollution. Surficial soil that has suffered non-pollution to mid-pollution of Zn accounts for 41%, 50%, and 7% for mid-pollution, and only 2% between mid-pollution to severe pollution. The maximal degree of Cu contamination is 5.09 in the surficial soil of Guiyang. Surficial soil that has not suffered Cu pollution accounts for 53.2%. The total pollution degree of Cu is slightly over zero. So the surficial soil of Guiyang has suffered slight Cu pollution. The maximum value of Zn contamination degree is 2.85 in the surficial soil of Guiyang. 77.8% of the surficial soil has not yet suffered any Zn pollution. The total pollution degree of Zn is less than zero.So the surficial soil in Guiyang is free from pollution of Zn.

  6. Soil and Human Interactions in Maya Wetlands

    Science.gov (United States)

    Beach, Timothy; Luzzadder-Beach, Sheryl

    2013-04-01

    Since the early 1990s, we have studied Maya interaction with soils in Mexico, Belize, Guatemala, and elsewhere. We studied upland and lowland soils, but here we focus on seasonal or 'Bajo' wetlands and perennial wetlands for different reasons. Around the bajos, the ancient Maya focused on intensive agriculture and habitation despite the difficulties their Vertisol soils posed. For the perennial wetlands, small populations spread diffusely through Mollisol and Histisol landscapes with large scale, intensive agro-ecosystems. These wetlands also represent important repositories for both environmental change and how humans responded in situ to environmental changes. Work analyzing bajo soils has recorded significant diversity but the soil and sediment record shows two main eras of soil instability: the Pleistocene-Holocene transition as rainfall fluctuated and increased and tropical forest pulsed through the region, and the Maya Preclassic to Classic 3000 to 1000 BP as deforestation, land use intensity, and drying waxed and waned. The ancient Maya adapted their bajo soil ecosystems successfully through agro-engineering but they also withdrew in many important places in the Late Preclassic about 2000 BP and Terminal Classic about 1200 BP. We continue to study and debate the importance of perennial wetland agro-ecosystems, but it is now clear that Maya interaction with these soil landscapes was significant and multifaceted. Based on soil excavation and coring with a broad toolkit of soil stratigraphy, chemistry, and paleoecology from 2001 to 2013, our results show the ancient Maya interacted with their wetland soils to maintain cropland for maize, tree crops, arrow root, and cassava against relative sea level rise, increased flooding, and aggradation by gypsum precipitation and sedimentation. We have studied these interactions across an area of 2000 km2 in Northern Belize to understand how Maya response varied and how these soil environments varied over time and distance

  7. Scoping Agriculture, Wetland Interactions

    OpenAIRE

    2015-01-01

    Agriculture is identified as the main cause of wetland degradation and loss. Using a drivers, pressures, state changes, impacts and responses (DPSIR) framework to analyze 90 cases drawn from all parts of the world and all wetland types, this report assesses the character of agriculture - wetlands interactions (AWIs) and their impacts in socio-economic and ecosystem services terms. The report is a technical framework that is used to scope out the relevance and nature of AWIs, identify response...

  8. Sediment-Tracing Technology: An Overview

    Science.gov (United States)

    2006-09-01

    flattening of the profile of 210Pb activity versus depth in the surficial sediment layers, and degradation of the 137Cs peak (Appleby 2001). In the CRS model...parameters can be diagnostic of mineral type and origin; they are sensitive to chemical and thermal transformations and can reflect the ambient magnetic...feldspar, calcite , and water. When the magnetic field is removed, diamagnetism is lost. b. Paramagnetism: When a magnetic field is applied to a

  9. Transfer of pesticides and copper in a stormwater wetland receiving contaminated runoff from a vineyard catchment

    Science.gov (United States)

    Maillard, E.; Babcsanyi, I.; Payraudeau, S.; Imfeld, G.

    2012-04-01

    Wetlands can collect contaminated runoff from urban and agricultural catchments, and have intrinsic physical, chemical and biological processes useful for mitigating pesticides. However, knowledge about the ability of wetlands to mitigate pesticide mixtures in runoff is currently very limited. Our results show that stormwater wetlands that primarily serve for flood protection can also be effective tools for reducing concentrations and loads of runoff-related pesticides. Concentrations and loads of 20 pesticides and degradation products, as well as copper were continuously recorded during the period of pesticide application (April to September 2009, 2010 and 2011) at the inlet, the outlet and in sediments of a stormwater wetland that collects runoff from a vineyard catchment. Removal rates of dissolved loads ranged from 39% (simazine) to 100% (cymoxanil, gluphosinate, kresoxim methyl and terbuthylazine). Dimethomorph, diuron, glyphosate and metalaxyl were more efficiently removed in spring than in summer. The calculation of sedimentation rates from discharge measurements and total suspended solids (TSS) values revealed that the wetland retained more than 77% of the input mass of suspended solids, underscoring the capability of the wetland to trap pesticide-laden particles. Only flufenoxuron was frequently detected in the wetland sediments. An inter-annual comparison showed that changes in the removal of aminomethylphosphonic acid (AMPA, a degradation product of glyphosate), isoxaben or simazine can be attributed mainly to the larger vegetation cover in 2010 compared to 2009. More than 80% of the copper load entering the wetland was retained in the sediments and the plants. Our results demonstrate that stormwater wetlands can efficiently remove pesticide mixtures and copper in agricultural runoff during critical periods of pesticide application. Nevertheless, fluctuations in the runoff regime, as well as the vegetation and hydrochemical characteristics affect the

  10. Sedimentological characteristics of the surficial deposits of the Jal Az-Zor area, Kuwait

    Science.gov (United States)

    Al-Bakri, D.; Kittaneh, W.; Shublaq, W.

    1988-10-01

    and carbonates) are controlled by the chemistry and hydrodynamics of the groundwater which in turn are controlled mostly by the climatic conditions, during their development, and the lithology of the host sediments. Arid and semi-arid climatic and paleoclimatic conditions are considered the most critical factors affecting the depositional and diagenetic processes impacting surficial deposits of the Jal Az-Zor area.

  11. Textural description of surface sediment samples collected in March/April 2014 and October 2014 from Chincoteague Bay, Virginia and Maryland (U.S. Geological Survey Field Activity Numbers 14CTB01, and 14CTB22).

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Scientists from the U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center conducted a seasonal collection of surficial sediments from Chincoteague...

  12. Sediment Sample Locations Collected in March/April 2014 and October 2014 from Chincoteague Bay, Virginia and Maryland (U.S. Geological Survey Field Activity Numbers 14CTB01, and 14CTB22)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Scientists from the U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center conducted a seasonal collection of surficial sediments from Chincoteague...

  13. Textural description of surface sediment samples collected in March/April 2014 and October 2014 from Chincoteague Bay, Virginia and Maryland (U.S. Geological Survey Field Activity Numbers 14CTB01, and 14CTB22).

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Scientists from the U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center conducted a seasonal collection of surficial sediments from Chincoteague...

  14. Isochron of Holocene marine (Qmn and Qmd) sediment thickness on the Massachusetts inner continental shelf between Nahant and Northern Cape Cod Bay (qmiso Esri binary grid; UTM, Zone 19N, WGS 84)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data are qualitatively derived interpretive polygon shapefiles and selected source raster data defining surficial geology, sediment type and distribution, and...

  15. Isochron of Holocene fluvial and estuarine (Qfe) sediment thickness beneath the Massachusetts inner continental shelf between Nahant and Northern Cape Cod Bay (qfeiso Esri binary grid; UTM, Zone 19N, WGS 84)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data are qualitatively derived interpretive polygon shapefiles and selected source raster data defining surficial geology, sediment type and distribution, and...

  16. Isochron of Holocene marine (Qmn and Qmd) sediment thickness on the Massachusetts inner continental shelf between Nahant and Northern Cape Cod Bay (qmiso Esri binary grid; UTM, Zone 19N, WGS 84)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data are qualitatively derived interpretive polygon shapefiles and selected source raster data defining surficial geology, sediment type and distribution, and...

  17. Isochron of Holocene fluvial and estuarine (Qfe) sediment thickness beneath the Massachusetts inner continental shelf between Nahant and Northern Cape Cod Bay (qfeiso Esri binary grid; UTM, Zone 19N, WGS 84)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data are qualitatively derived interpretive polygon shapefiles and selected source raster data defining surficial geology, sediment type and distribution, and...

  18. Sediment Sample Locations Collected in March/April 2014 and October 2014 from Chincoteague Bay, Virginia and Maryland (U.S. Geological Survey Field Activity Numbers 14CTB01, and 14CTB22)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Scientists from the U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center conducted a seasonal collection of surficial sediments from...

  19. Use of Multi-Media Sampling as Integrated Approach to Surficial Geochemical Sampling for Gold in Regional Reconnaissance Surveys in Parts of the Ashanti Belt, Southwest Ghana

    Directory of Open Access Journals (Sweden)

    Prosper M. Nude

    2013-01-01

    Full Text Available This study compared the conventional method used in surficial geochemical sampling to multimedia sampling method during reconnaissance surveys in gold exploration. The use of the conventional method in regional reconnaissance exploration surveys whereby surficial geochemical sampling is done step-wise, first by sampling stream sediments followed by rock chips then soils and other regolith materials in the search and defining of prospective targets of gold mineralization appears inefficient in geological environments characterized by complex regolith and landform modifications. However, multi-media geochemical sampling which involves the simultaneous sampling of different geochemical samples appears a better alternative and eliminates false and erratic anomalies often associated with the sampling of a single medium. Multi-media samples comprising rock chips, scree, termite mounds and lateritic lags, were collected simultaneously to support stream sediments in parts of the Ashanti belt in the Birimian of southwest Ghana, which is characterized by complex regolith and landform modifications. The most prospective targets among the three anomalous zones defined by the stream survey were better pronounced with the support of the other media, based on the consistency in significant gold contents in those samples. Gold assay values from the multi-media samples ranked the Manso East target as the most prospective and the Manso Northwest target being least prospective due to the inconsistent gold assay values in the different media. Thus the integration of the gold assay values from the various media defined real and prospective geochemical gold targets better than in the conventional method in which sampling of different media was done in stages. Unlike the conventional method, the multi-media survey provided gold results that showed regional, proximal and in-situ anomalies simultaneously. Multi-media geochemical survey therefore, appears to be a

  20. A Hydraulic Nexus between Geographically Isolated Wetlands and Downstream Water Bodies

    Science.gov (United States)

    Mclaughlin, D. L.; Kaplan, D. A.; Cohen, M. J.

    2014-12-01

    Geographic isolation does not imply hydrological isolation; indeed, local groundwater exchange between geographically isolated wetlands (GIWs) and surrounding uplands may yield important controls on regional hydrology. Differences in specific yield (Sy) between aquifers and inundated GIWs drive differences in water level responses to atmospheric fluxes, leading to frequent reversals in hydraulic gradients that cause GIWs to act as both groundwater sinks and sources. When distributed across the landscape, these reversals in local groundwater fluxes are predicted to collectively buffer the surficial aquifer and its regulation of baseflow delivery, a process we refer to as landscape hydrologic capacitance. To test this hypothesis, we integrated models of daily soil moisture, upland water table, and wetland stage dynamics to simulate hydrology of a low-relief landscape with GIWs. Simulations explored the influences of cumulative wetland area, individual wetland size, climate, and soil texture on water table and baseflow variation. Increasing cumulative wetland area and decreasing individual wetland size reduced water table variation and the frequency of extremely shallow and deep water tables. This buffering effect extended to baseflow deliveries, decreasing the standard deviation of daily baseflow by as much as 50%. For the same total wetland area, landscapes with fewer (i.e., larger) wetlands exhibited markedly lower hydrologic capacitance than those with more (i.e., smaller) wetlands, highlighting the important role of small GIWs in regulating regional hydrology. Recent U.S. Supreme Court rulings have limited federal protections for GIWs except where a "significant nexus" to a navigable water body is demonstrated. Our results suggest that GIWs regulate downstream baseflow, even where water in GIWs may never physically reach downstream systems, providing a significant "hydraulic" nexus to distant water bodies.

  1. 基于光释光测年研究青海湖三种沼泽湿地的发育及沉积速率%The Study of Formation and Sedimentation Rate of Three Typical Wetlands in Qinghai Lake Watershed Using Luminescence Technique

    Institute of Scientific and Technical Information of China (English)

    刘德梅; 陈桂琛; 赖忠平; 刘向军; 周国英; 宋文珠; 彭敏

    2012-01-01

    近百年来由于受气候暖干化、青海湖湖体水位下降和周围草地退化及沙化趋势加剧等生态环境变化,加速了湿地环境变迁的生态过程.本研究在青海湖北岸地区选取三种典型沼泽湿地(藏嵩草kobresia tibetica、华扁穗草Blysmus sinocompressus、盐地凤毛菊Saussurea salsa),建立地层的年代序列,计算得到每一测年段内的沉积速率,结合前人研究的历史气候变化,分析湿地形成的历史背景,初步揭示三种沼泽湿地的发育和沉积规律与全球变化的耦合性.结果表明光释光测得的三种沼泽湿地其发育时期各不相同,华扁穗草沼泽湿地发育于8.436±0.6ka,藏嵩草沼泽湿地发育于2.058±0.11 ka,盐地凤毛菊沼泽湿地发育于1.143±0.20 ka;从整个剖面的平均沉积速率来看盐地凤毛菊湿地沉积最快(0.63 mm/a),藏嵩草湿地次之(0.39 mm/a),华扁穗湿地最慢(0.09 mm/a).三种沼泽湿地主要在气候由暖干向湿润期转变时形成,自形成以来由于受到全球变化和人类因素的影响,沉积并非随时间呈线性关系发展.%In recent years, due to the warm and dry climate, Lake water-level decline and grassland degradation , desertification, it speeds up ecology process of wetland environment, which seriously impact on the sustainable development of Qinghai Lake watershed. In this study, sediment cores were sampled and dated using optically stimulated luminescence (OSL) dating method at three typical wetlands in north shore of Qinghai lake. Dating of sediment cores was used to establish the wetland sedimentary chrono-se-quence, calculate sediment accumulation rates. Analysed wetland formation' s history background from paleoclimate change of previous research in local. Preliminarily reveals three wetlands formation and sedimentary regularity, and relate to the global climate change. The results showed that all OSL samples have strong signals and De value approximate Gaussian Distribution

  2. Reconstruction of Anacostia wetlands: success?

    Science.gov (United States)

    Hammerschlag, R.S.; Perry, M.C.

    2002-01-01

    Historically, the tidal Anacostia River in Washington, D.C. had been an extensive system of freshwater tidal marshes replete with a full array of wetland vegetation dominated by wild rice. The local Nacochtank Indians had found the abundant fish and wildlife sufficient to sustain their daily lives. White man's intrusion upon the landscape gradually brought about deterioration of the natural (and associated cultural) system. Total demise followed mid-20th century dredge and fill channelization, which was conducted from the confluence of the Anacostia with the Potomac near the heart of Washington, D.C. to the terminus of the tidal regime at Bladensburg, Maryland. The National Park Service (NPS) became the manager for much of the land along the Anacostia, particularly the eastern bank. As part of its planning effort, the NPS envisioned returning portions of the Anacostia under its control to a natural system as a vignette. The concept was based on bringing back as comprehensive a collection of vegetation and wildlife as possible through the reestablishment of tidal marshes at Kenilworth and Kingman. The resultant wetlands were to be made accessible to the public both logistically and through a well designed interpretative program. In fact, this vision has been realized due to an impressive cooperative effort among a number of Federal and local agencies and organizations. In 1993, 32 acres of freshwater tidal marsh were reconstructed at Kenilworth. Based upon the 5-year monitoring program that has been in place since reconstruction, several generalizations may be made concerning the degree of success of the marsh reconstruction. Water quality in the marsh system and nearby tidal waters has not been noticeably improved. The poor quality may be clue to the overwhelmingly high loads (e.g., sediment, nutrients, etc.) brought in on the twice daily tidal cycle from the Anacostia and to the relatively small volume of water which actually interacts with the emergent marsh

  3. Improving Antarctic Surficial Geology Maps through Spectroscopic Remote Sensing

    Science.gov (United States)

    Niebuhr, S.

    2013-12-01

    Spectral identification of lithologic units can be effectively used to improve legacy and outdated geologic maps for exposed rock outcrops in Antarctica. High resolution, multispectral satellite imagery provides a comprehensive view of surface geology in Antarctica and unique lithologic spectral signatures are used to identify geologic unit extent and distribution. Although lack of ancillary data and low solar illumination angles at high latitudes introduce difficulties such as terrain and nadir shadows in polar regions, this study utilizes 8-band WorldView-2 imagery to (1) separate spectrally distinguishable geologic units and map contacts in remote regions and (2) map and identify individual units in areas with detailed supporting information from previous in-situ observations and field campaigns (e.g., the McMurdo Dry Valleys) using textural and spectral image analysis. This ability to remotely identify surficial lithology at sub-meter scale enables detailed geologic interpretations for highly inaccessible areas and may potentially decrease the need for costly logistics, field work and reconnaissance.

  4. Attributes for NHDPlus Catchments (Version 1.1) for the Conterminous United States: Surficial Geology

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set represents the area of surficial geology types in square meters compiled for every catchment of NHDPlus for the conterminous United States. The source...

  5. Geology, Surficial, Neuse River Basin Mapping Project Surficial Geology - LIDAR �Äö?Ñ?¨ Ongoing project in Middle Coastal Plain to characterize geomorphology, surficial geology, shallow aquifers and confining units; shape file with surficial geology interpreted from LI, Published in 2007, 1:24000 (1in=2000ft) scale, NC DENR / Div. of Land Resources / Geological Survey Section.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Geology, Surficial dataset, published at 1:24000 (1in=2000ft) scale, was produced all or in part from LIDAR information as of 2007. It is described as 'Neuse...

  6. Surficial geology of the Cabot 7 1/2 minute quadrangle, Vermont

    Data.gov (United States)

    Vermont Center for Geographic Information — Digital data from VG2016-3 Springston, G., 2016, Surficial geology of the Cabot 7 1/2 minute quadrangle, Vermont: Vermont Geological Survey Open File Report...

  7. A Surficial Hydrogeologic Framework for the Mid-Atlantic Coastal Plain.

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The hydrogeologic framework was developed from a combination of the physiography and the predominant texture of surficial geologic units in the Mid-Atlantic Coastal...

  8. Surficial Geologic Map of the Pico Peak, Vermont 7.5 Minute Quadrangle

    Data.gov (United States)

    Vermont Center for Geographic Information — "Digital data from VG12-1 Wright, S., 2012, Surficial Geologic Map of the Pico Peak, Vermont 7.5 Minute Quadrangle: Vermont Geological Survey Open File Report...

  9. Overlying surficial deposits and absent areas for the Madison Limestone, Black Hills area, South Dakota.

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set describes areas where the Madison Limestone is directly overlain by surficial deposits, as well as those areas where the Madison Limestone is absent...

  10. Overlying surficial deposits and absent areas for Minnekahta Limestone in the Black Hills area, South Dakota

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set describes areas where the Minnekahta Limestone is directly overlain by surficial deposits, as well as those areas where the Minnekahta Limestone is...

  11. Surficial geologic map of the Knox Mountain area, Marshfield and Peacham, Vermont

    Data.gov (United States)

    Vermont Center for Geographic Information — Digital data from VG08-4 Springston, G. and Kim, J., 2008, Surficial geologic map of the Knox Mountain area, Marshfield and Peacham, Vermont: VGS Open-File Report...

  12. Hydrology and Ecology of Freshwater Wetlands in Central Florida - A Primer

    Science.gov (United States)

    Haag, Kim H.; Lee, Terrie M.

    2010-01-01

    how wetlands are affected by human activities. Freshwater wetlands are unique and complex ecosystems defined by characteristic properties. Wetlands usually have standing water during at least part of the year, although water depths can vary from a few inches to as much as several feet from one wetland to another. The hydrologic behavior of wetlands is influenced by drainage basin characteristics, as well as by natural variations in climate. Wetlands in central Florida (especially forested wetlands) often have acidic waters that are darkly stained from organic substances released by decomposing leaves and other plant material. Wetlands are characterized by biogeochemical cycles in which vital elements such as carbon, nitrogen, phosphorus, and others are transformed as they move between wetland soils and sediments, the open water, and the atmosphere. Wetlands are populated with plants that can thrive under conditions of saturated soils and low dissolved-oxygen concentrations. The bottoms of many wetlands, especially marshes, are covered with decayed plant material that can accumulate over time to form brown peat or black muck soils. Wetlands are inhabited by animals that need standing water to complete some or all of their life cycles, and they also provide periodic food, water, and shelter for many other animals that spend most of their lives on dry land. The complex and interrelated components of wetlands directly affect one another and there are numerous feedback mechanisms.

  13. Ebullitive methane emissions from oxygenated wetland streams.

    Science.gov (United States)

    Crawford, John T; Stanley, Emily H; Spawn, Seth A; Finlay, Jacques C; Loken, Luke C; Striegl, Robert G

    2014-11-01

    Stream and river carbon dioxide emissions are an important component of the global carbon cycle. Methane emissions from streams could also contribute to regional or global greenhouse gas cycling, but there are relatively few data regarding stream and river methane emissions. Furthermore, the available data do not typically include the ebullitive (bubble-mediated) pathway, instead focusing on emission of dissolved methane by diffusion or convection. Here, we show the importance of ebullitive methane emissions from small streams in the regional greenhouse gas balance of a lake and wetland-dominated landscape in temperate North America and identify the origin of the methane emitted from these well-oxygenated streams. Stream methane flux densities from this landscape tended to exceed those of nearby wetland diffusive fluxes as well as average global wetland ebullitive fluxes. Total stream ebullitive methane flux at the regional scale (103 Mg C yr(-1) ; over 6400 km(2) ) was of the same magnitude as diffusive methane flux previously documented at the same scale. Organic-rich stream sediments had the highest rates of bubble release and higher enrichment of methane in bubbles, but glacial sand sediments also exhibited high bubble emissions relative to other studied environments. Our results from a database of groundwater chemistry support the hypothesis that methane in bubbles is produced in anoxic near-stream sediment porewaters, and not in deeper, oxygenated groundwaters. Methane interacts with other key elemental cycles such as nitrogen, oxygen, and sulfur, which has implications for ecosystem changes such as drought and increased nutrient loading. Our results support the contention that streams, particularly those draining wetland landscapes of the northern hemisphere, are an important component of the global methane cycle.

  14. Ebullitive methane emissions from oxygenated wetland streams

    Science.gov (United States)

    Crawford, John T.; Stanley, Emily H.; Spawn, Seth A.; Finlay, Jacques C.; Striegl, Robert G.

    2014-01-01

    Stream and river carbon dioxide emissions are an important component of the global carbon cycle. Methane emissions from streams could also contribute to regional or global greenhouse gas cycling, but there are relatively few data regarding stream and river methane emissions. Furthermore, the available data do not typically include the ebullitive (bubble-mediated) pathway, instead focusing on emission of dissolved methane by diffusion or convection. Here, we show the importance of ebullitive methane emissions from small streams in the regional greenhouse gas balance of a lake and wetland-dominated landscape in temperate North America and identify the origin of the methane emitted from these well-oxygenated streams. Stream methane flux densities from this landscape tended to exceed those of nearby wetland diffusive fluxes as well as average global wetland ebullitive fluxes. Total stream ebullitive methane flux at the regional scale (103 Mg C yr−1; over 6400 km2) was of the same magnitude as diffusive methane flux previously documented at the same scale. Organic-rich stream sediments had the highest rates of bubble release and higher enrichment of methane in bubbles, but glacial sand sediments also exhibited high bubble emissions relative to other studied environments. Our results from a database of groundwater chemistry support the hypothesis that methane in bubbles is produced in anoxic near-stream sediment porewaters, and not in deeper, oxygenated groundwaters. Methane interacts with other key elemental cycles such as nitrogen, oxygen, and sulfur, which has implications for ecosystem changes such as drought and increased nutrient loading. Our results support the contention that streams, particularly those draining wetland landscapes of the northern hemisphere, are an important component of the global methane cycle.

  15. Wetland Loss and Restoration Options in Southern Louisiana

    Science.gov (United States)

    Dean, Robert G.

    2008-03-01

    Wetlands are productive landscape features of the broad Mississippi River Delta system. In addition to their ecological services of providing habitats for a variety of species including juvenile commercial and recreational fish, they provide a valuable wave reduction role during severe storm events characterized by elevated water levels and high waves. Currently, these wetlands are stressed by a combination of natural and human-related forces resulting in rapid loss rates. Although many factors contribute to wetland loss rates, the single greatest factor is the shunting of river borne sediments offshore into deep water. Navigational interests benefit greatly from the present fixed location of the main navigation channel at Southwest pass with its terminus at the edge of the continental shelf such that the sediment load is discharged into deep water. The Mississippi River Delta region is subsiding at up to more than 10 times the Eustatic rate of sea level rise and thus the wetland and barrier island systems require these sediments for maintenance and growth. With the increasing scarcity and costs of energy, it is highly desirable that wetland restoration be done using natural forces to the degree possible. Absent legal issues, a pragmatic approach could be to identify those areas where progress can be made with realistic investments of economic and energy resources and to accept that areas with less benefit per investment will continue to degrade. The paper will review various options and discuss obstacles and opportunities.

  16. The release and oxidation of ammonia at the sediment-water interface of Jiulong River Estuary wetland under different oxygen conditions%不同溶氧条件下九龙江口湿地沉积物-水界面氨氮释放与氧化规律

    Institute of Scientific and Technical Information of China (English)

    邱昭政; 颜昌宙; 赵艳玲; 杜苗苗; 罗专溪

    2011-01-01

    The release and oxidation of NH4+-N in the intertidal sediments is a critical process of the nitrogen biogeochemical cycle in the estuarine wetland ecosystems. This study investigated the release and oxidation mechanisms of NH4+-N at the sediment-water interface of two kinds of Jiulong River Estuary Wetland sediments under four dissolved oxygen conditions (saturated, aerobic, anoxic and anaerobic). The results showed that the ways of NH4+-N release and oxidation in two sediments with different vegetation were significantly different under four dissolved oxygen conditions. Firstly, the release of NH4+-N from mangrove sediment to overlying water was 0.9~3.5 times than mudflat sediments, and the release of NH4+-N from mangrove sediments to overlying water were 1.64 mg (saturated), 2.07 mg (aerobic), 3.47 mg (anoxic) and 3.20 mg(anaerobic), respectively;while from mudflat sediments they were 0.85 mg, 1.00 mg, 0.77 mg and 1.27 mg, respectively. The amount of sediment NH4+-N release was low at high DO condition, but high at low DO condition. Secondly, the release rate and oxidation rate of NH4+-N in the mangrove sediments were 43.73~48.51 mgN·m-2-d·-1 and 26.19~40.68 mgN·m-2·d-1, respectively, which were higher than that (14.50~19.22 mgN·m-2·d-1 and 8.35-22.53 mgN·m-2·d-1) in the mudflat sediments. The reason was possibly that the microorganism species in mangrove sediments were richer than mudflat sediments, resulting in the higher degree of the mineralization and nitrification in mangrove sediments. This study revealed the transfer and transformation of NH4+-N in two sediments under different gradients of dissolved oxygen, which would benefit the decision-making process for the protection of coastal wetlands and the control of coastal water eutrophication.%沉移物中氨氮( NH4+-N)的释放与氧化是河口湿地生态系统氮素生物地球化学循环的关键过程.本文通过室内模拟,构建饱和(BH)、好氧(HY)、缺氧(QY)和厌氧(YY)

  17. Wetlands: Earth's Kidneys

    Science.gov (United States)

    Wetlands are unique, diverse, and productive habitats that emerge at the fringe of aquatic and upland land systems. The U.S. Environmental Protection Agency (EPA) defines wetlands as "areas that are regularly inundated by surface water or groundwater and characterized by a preva...

  18. Microbiology of wetlands

    NARCIS (Netherlands)

    Bodelier, P.L.E.; Dedysh, S.N.

    2013-01-01

    Wetlands are ecologically as well as economically important systems due to their high productivity, their nutrient (re)cycling capacities, and their prominent contribution to global greenhouse gas emissions. Being on the transition between terrestrial and—aquatic ecosystems, wetlands are buffers for

  19. Good Wetland Agricultural Practices

    NARCIS (Netherlands)

    Hengsdijk, H.; Zingstra, H.L.

    2009-01-01

    Within the Guiding Agriculture Wetland Interaction (GAWI) project the Driver!Pressure!State! Impact!Response (DPSIR) approach has been adopted to describe and analyse agriculture!wetland interactions. The DPSIR approach provides a consistent framework to analyse the complex causal chain among

  20. EBSSED database-Surficial sediments of the eastern Bering Sea continental shelf

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In order to facilitate descriptions of groundfish habitat over a large portion of the EBS shelf, the NMFS/AFSC has assembled a single comprehensive database of the...

  1. On the surficial sediments of the fresh water Naini Lake, Kumaun Himalaya, India

    Digital Repository Service at National Institute of Oceanography (India)

    Jauhari, P.; Hashimi, N.H.

    The 1.4 km long and 0.45-0.25 km wide crescent shaped Naini Lake in the Nainital District of Kumaun Himalaya, India is divided by an east-west running transverse Central Ridge into two sub-basins. These northwest and southeast sub...

  2. Sup(10)Be variation in surficial sediments of the Central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Nath, B.N.; Aldahan, A.; Possnert, G.; Selvaraj, K.; Mascarenhas-Pereira, M.B.L.; Chen, C.T.A.

    , Geochim. Cosmo- chim. Acta 60 (1996) 213. [8] V.K. Banakar, S.M. Gupta, V.K. Padmavathi, Mar. Geol. 96 (1991) 167. [9] D.V. Borole, Deep-Sea Res. 40 (1993) 761. [10] B.L.K. Somayajulu, P. Sharma, J. Beer, G. Bonani, H.J. Hofmann, E. Morenzoni, M. Nessi, M...

  3. Otoliths in continental shelf and slope surficial sediments off Saurashtra, Arabian Sea, India and their significance

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.; John, S.; Rana, R.S.

    is in progress and will be reported in due course. This preliminary report which is the first report from the northern Arabian Sea on fossil fish otolith may help as an additional tool in the reconstruction of paleoenvironment and in assessing the latitudinal...

  4. n-Alkanes in surficial sediments of Visakhapatnam harbour, east coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Punyu, V.R.; Harji, R.R.; Bhosle, N.B.; Sawant, S.S.; Venkat, K.

    . Tetracyclic and tri- cyclic terpanes are found in crude oil and fossil fuel, respectively (Moldowan and Seifert 1983; Aboul-Kassim and Simoneit 1996; Sanchez and Permanyer 2006). These were detected at stations 3, 5, 6, 12 and 19. The mass fragmentograms... 456–468. Mackenzie A S, Brassel S C, Eglington J and Maxwell J R 1982 Chemical fossils: The geological fate of steroids; Science 217 491–504. Maioli O L G, Rodrigues K C, Knoppers B A and Azevedo D A 2011 Distribution and sources of aliphatic and poly...

  5. Marine Ecosystems Analysis (MESA) Program, New York Bight Surficial Sediment Analyses

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Marine Ecosystems Analysis (MESA) Program, New York Bight Study was funded by NOAA and the Bureau of Land Management (BLM). The Atlas was a historical...

  6. Channel morphometry, sediment transport, and implications for tectonic activity and surficial ages of Titan basins

    Science.gov (United States)

    Cartwright, Richard; Clayton, Jordan A.; Kirk, Randolph L.

    2011-01-01

    Fluvial features on Titan and drainage basins on Earth are remarkably similar despite differences in gravity and surface composition. We determined network bifurcation (Rb) ratios for five Titan and three terrestrial analog basins. Tectonically-modified Earth basins have Rb values greater than the expected range (3.0–5.0) for dendritic networks; comparisons with Rb values determined for Titanbasins, in conjunction with similarities in network patterns, suggest that portions of Titan's north polar region are modified by tectonic forces. Sufficient elevation data existed to calculate bed slope and potential fluvial sedimenttransport rates in at least one Titanbasin, indicating that 75 mm water ice grains (observed at the Huygens landing site) should be readily entrained given sufficient flow depths of liquid hydrocarbons. Volumetric sedimenttransport estimates suggest that ~6700–10,000 Titan years (~2.0–3.0 x 105 Earth years) are required to erode this basin to its minimum relief (assuming constant 1 m and 1.5 m flows); these lowering rates increase to ~27,000–41,000 Titan years (~8.0–12.0 x 105 Earth years) when flows in the north polar region are restricted to summer months.

  7. Diversity and bioactive potentials of culturable heterotrophic bacteria from the surficial sediments of the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Anas, A.; Nilayangod, C.; Jasmin, C.; Vinothkumar, S.; Parameswaran, P.S.; Nair, S.

    . BMC Bioinform 12:385 Pai SS et al (2010) Penaeus monodon larvae can be protected from Vibrio harveyi infection by pre-emptive treatment of a rearing system with antagonistic or non-antagonistic bacterial probiotics. Aquac Res 41:847–860 Paulmier A...). Preparation of organic extracts Organic extract of 131 isolates was prepared using ethyl acetate as solvent. Bacterial isolates for the production of secondary metabolites were prepared in basal medium. Briefly, 100 ll of bacterial inoculum (1.0 OD at 600 nm...

  8. Patterns of short-term sedimentation in a freshwater created marsh.

    Science.gov (United States)

    Harter, Sarah K; Mitsch, William J

    2003-01-01

    This study investigated different sedimentation measurement techniques and examined patterns of short-term sedimentation in two 1-ha replicate created freshwater marshes in central Ohio, USA. Short-term (one-year) sediment accumulation above feldspar, clay, glitter, and sand artificial marker horizons was compared at different water depths and distances from wetland inflow. A sediment budget was also constructed from turbidity and suspended sediment data for comparison with marker horizons. Glitter and sand marker horizons were the most successful for measuring sediment accumulation (81-100% marker recovery), while clay markers were completely unsuccessful. The sedimentation rate for both wetlands averaged 4.9 cm yr(-1) (36 kg m(-2) yr(-1)), and ranged from 1.82 to 9.23 cm yr(-1) (12.4 to 69.7 kg m(-2) yr(-1)). Sedimentation rates in deep, open water areas were significantly higher than in shallow, vegetated areas for both wetlands (t test, p wetlands, suggesting that bioturbation and turbulence may cause significant resuspension or that high hydrologic loads may distribute sediments throughout the basins. A sediment budget estimated sediment retention of approximately 740 g m(-2) yr(-1) per wetland (43% removal rate), yet gross sediment accumulation was 36,000 g m(-2) yr(-1) measured by marker horizons. These results suggest that erosive forces may have influenced sedimentation, but also may indicate problems with the sediment budget calculation methodology.

  9. Bioavailability of sediment-associated mercury to Hexagenia mayflies in a contaminated flood plain river

    Energy Technology Data Exchange (ETDEWEB)

    Naimo, T.J.; Wiener, J.G.; Cope, W.G. [U.S. Geological Survey, La Crosse, WI (United States). Biological Resources Division; Bloom, N.S. [Frontier Geosciences, Seattle, WA (United States)

    2000-05-01

    The bioavailability of mercury in sediments from the Sudbury River in Massachusetts was studied, as it related to the mayfly nymphs. The nymphs were exposed to contaminated and reference sediments (treatments) from reservoirs, flowing reaches, palustrine wetlands, and a riverine lake in four 21-day bioaccumulation tests. The mean final concentrations of methyl mercury (MeHg) in test water were greatest in treatments with contaminated wetland sediments. In the case of mayflies, the final mean concentrations of MeHg were highest in treatments with contaminated wetland sediments, intermediate in treatments with contaminated sediments from reservoirs, flowing reaches, and a riverine lake, and lowest in treatments with reference sediments. It was concluded that even though contaminated reservoirs had the most contaminated sediments, the potential entry of MeHg into the benthic food chain was greater in contaminated palustrine wetlands. 2 tabs., 5 figs., 42 refs.

  10. Hurricane-induced failure of low salinity wetlands

    Science.gov (United States)

    Howes, Nick C.; FitzGerald, Duncan M.; Hughes, Zoe J.; Georgiou, Ioannis Y.; Kulp, Mark A.; Miner, Michael D.; Smith, Jane M.; Barras, John A.

    2010-01-01

    During the 2005 hurricane season, the storm surge and wave field associated with Hurricanes Katrina and Rita eroded 527 km2 of wetlands within the Louisiana coastal plain. Low salinity wetlands were preferentially eroded, while higher salinity wetlands remained robust and largely unchanged. Here we highlight geotechnical differences between the soil profiles of high and low salinity regimes, which are controlled by vegetation and result in differential erosion. In low salinity wetlands, a weak zone (shear strength 500–1450 Pa) was observed ∼30 cm below the marsh surface, coinciding with the base of rooting. High salinity wetlands had no such zone (shear strengths > 4500 Pa) and contained deeper rooting. Storm waves during Hurricane Katrina produced shear stresses between 425–3600 Pa, sufficient to cause widespread erosion of the low salinity wetlands. Vegetation in low salinity marshes is subject to shallower rooting and is susceptible to erosion during large magnitude storms; these conditions may be exacerbated by low inorganic sediment content and high nutrient inputs. The dramatic difference in resiliency of fresh versus more saline marshes suggests that the introduction of freshwater to marshes as part of restoration efforts may therefore weaken existing wetlands rendering them vulnerable to hurricanes. PMID:20660777

  11. Sidescan-Sonar Imagery and Surficial Geologic Interpretations of the Sea Floor in Central Rhode Island Sound

    Science.gov (United States)

    McMullen, K.Y.; Poppe, L.J.; Denny, J.F.; Haupt, T.A.; Crocker, J.M.

    2008-01-01

    The U.S. Geological Survey (USGS) has been working with the National Oceanic and Atmospheric Administration (NOAA) to interpret the surficial geology of areas along the northeastern coast of the United States. During 2004, the NOAA Ship RUDE conducted Hydrographic Survey H11321 in Rhode Island Sound. This sidescan-sonar and bathymetry survey covers an area of 93 km? located 12 km southeast of Brenton Point, RI in water depths of 28-39 m (fig. 1). The purpose of this report is to delineate sea floor features and sedimentary environments of this area in central Rhode Island Sound using sidescan-sonar and bathymetric data from NOAA Survey H11321 and seismic-reflection data from a previous USGS field study (Needell and others, 1983a). This is important for the study of benthic habitats and provides a framework for future research. Prior work in this area includes the mapping of surface sediments and surficial geology. McMaster (1960) collected sediment samples from Rhode Island Sound and Narragansett Bay and mapped our study area as having a sandy sea floor. In addition, one sample of sand from the National Ocean Service (NOS) Hydrographic Database came from a location in the northeast part of our study area in 1939 (fig. 2; Poppe and others, 2003). McMaster and others (1968) used seismic-reflection profiles to map the locations of a cuesta of Cretaceous sediments crossing Rhode Island Sound and post-Cretaceous drainage channels. Knebel and others (1982) identified sedimentary environments in Rhode Island Sound using sidescan sonographs. Needell and others (1983b) studied the Quaternary geology and mapped the structure, sedimentary environments, and geologic hazards in Rhode Island Sound using sidescan-sonar and seismic-reflection data. Sidescan-sonar and bathymetric data from NOAA Survey H11320, which overlaps the far eastern edge of our study area, was interpreted to consist of basins surrounded by a moraine and bathymetric highs composed of till with areas of rocks

  12. Local biogeomorphic feedbacks and macroscale drivers shape coastal wetland distributions

    Science.gov (United States)

    Braswell, A. E.; Heffernan, J. B.

    2016-12-01

    Recent models have demonstrated that lateral biogeomorphic processes are important for the persistence of coastal wetlands in the face of sea level rise and other anthropogenic pressures. Yet empirical studies of marsh ecomorphodynamics have largely focused on vertical accretion. Moreover, local vertical and lateral processes of marsh-building depend on external sediment supply and the wave energy environment, and thus are connected to macroscale characteristics such as estuarine morphology and watershed size. These broad scale drivers, combined with local biogeomorphic feedbacks within wetlands, determine wetland extent. Our goal is to understand the scales at which local biogeomorphic feedbacks and macroscale estuarine and watershed characteristics influence the distribution of coastal marshes. To that end, we examined the distribution of wetland extent and its potential watershed and estuarine drivers at multiple scales along the Atlantic and Gulf coasts, USA. Using existing GIS resources, we delineated extents of coastal wetlands, and generated proxies of sediment input, estuarine energy, and human alteration. We found that distributions of wetland extent were bi-modal at the finest scale of our analysis (approx. 1-100 km2), a finding that is consistent with theoretical models of local marsh feedbacks. At larger spatial scales, distributions of marsh extent were associated with both estuarine size and drainage ratio. These relationships indicate that sediment supply and erosion ultimately constrain the extent of marsh development and persistence, while local feedbacks operate at smaller scales. Our findings support and extend theory and observation at the scale of marsh platforms and lagoons, but also demonstrate the importance of macroscale watershed and estuarine characteristics for wetland establishment and persistence.

  13. Clay particle retention in small constructed wetlands.

    Science.gov (United States)

    Braskerud, B C

    2003-09-01

    Constructed wetlands (CWs) can be used to mitigate non-point source pollution from arable fields. Previous investigations have shown that the relative soil particle retention in small CWs increases when hydraulic load increases. This paper investigates why this phenomenon occurs, even though common retention models predict the opposite, by studying clay and silt particle retention in two Norwegian CWs. Retention was measured with water flow proportional sampling systems in the inlet and outlet of the wetlands, and the texture of the suspended solids was analyzed. The surface area of the CWs was small compared to the watershed area (approximately 0.07%), giving high average hydraulic loads (1.1 and 2.0 md(-1)). One of the watersheds included only old arable land, whereas the other included areas with disturbed topsoil after artificial land leveling. Clay particle retention was 57% for the CW in the first watershed, and 22% for the CW in the disturbed watershed. The different behavior of the wetlands could be due to differences in aggregate size and stability of the particles entering the wetlands. Results showed that increased hydraulic loads did affect CW retention negatively. However, as runoff increased, soil particles/aggregates with higher sedimentation velocities entered the CWs (e.g., the clay particles behaved as silt particles). Hence, clay particle settling velocity is not constant as assumed in many prediction models. The net result was increased retention.

  14. A review of major storm impacts on coastal wetland elevations

    Science.gov (United States)

    Cahoon, D.R.

    2006-01-01

    Storms have long been recognized as agents of geomorphic change to coastal wetlands. A review of recent data on soil elevation dynamics before and after storms revealed that storms affected wetland elevations by storm surge, high winds, and freshwater flushing of the estuary (inferred). The data also indicate that measures of sediment deposition and erosion can often misrepresent the amount and even direction of elevation change because of storm influences on subsurface processes. Simultaneous influence on both surface and subsurface processes by storms means that soil elevation cannot always be accurately estimated from surface process data alone. Eight processes are identified as potentiatly influencing soil elevation: sediment deposition, sediment erosion, sediment compaction, soil shrinkage, root decomposition (following tree mortality from high winds), root growth (following flushing with freshwater, inferred), soil swelling, and lateral folding of the marsh root mat. Local wetland conditions (e.g., marsh health, tide height, groundwater level) and the physical characteristics of the storm (e.g., angle of approach, proximity, amount of rain, wind speed, and storm surge height) were apparently important factors determining the storm's effect on soil elevation. Storm effects on elevation were both permanent (on an ecological time scale) and short-lived, but even short-term changes have potentially important ecological consequences. Shallow soil subsidence or expansion caused by a storm must be considered when calculating local rates of relative sea level rise and evaluating storm effects on wetland stability.

  15. Tropical wetlands - problems and potentials as paleo-monsoon archives

    Science.gov (United States)

    Chabangborn, Akkaneewut; Chawchai, Sakonvan; Fritz, Sherilyn; Löwemark, Ludvig; Wohlfarth, Barbara

    2014-05-01

    Paleoclimatic and paleoenvironmental information is still scarce for Southeast Asia despite the fact that this large region is home to numerous natural lakes and wetlands that may contain long sedimentary archives. During the past years we have been surveying lakes and wetlands in different parts of Thailand to select the most promising and longest sedimentary sequences for paleoenvironmental studies. Our survey of more than 30 lakes shows that only very few lakes and wetlands still contain soft sediments. The sediments in the majority of the lakes and wetlands have been dredged and excavated during the past 10 years to provide open and clear water for fishing and recreation. Dredging and excavation using large caterpillars has disturbed and in some cases completely destroyed the sedimentary records. Stiff clays now drape most of the lake bottoms. Based on our extensive survey, we found five sites, from which we successfully obtained intact sediment sequences: Lakes Kumphawapi and Pa Kho in northeast Thailand, Nong Leng Sai in northern Thailand and Sam Roi Yod and Nong Thale Pron in southern Thailand. All of these sites contain a detailed sedimentary record covering the past 2000 years, two of the sites cover parts of or, the entire Holocene; and two sites have sediments covering the last Termination and MIS 3, respectively.

  16. Monitoring and modeling wetland chloride concentrations in relationship to oil and gas development

    Science.gov (United States)

    Post van der Burg, Max; Tangen, Brian A.

    2015-01-01

    Extraction of oil and gas via unconventional methods is becoming an important aspect of energy production worldwide. Studying the effects of this development in countries where these technologies are being widely used may provide other countries, where development may be proposed, with some insight in terms of concerns associated with development. A fairly recent expansion of unconventional oil and gas development in North America provides such an opportunity. Rapid increases in energy development in North America have caught the attention of managers and scientists as a potential stressor for wildlife and their habitats. Of particular concern in the Northern Great Plains of the U.S. is the potential for chloride-rich produced water associated with unconventional oil and gas development to alter the water chemistry of wetlands. We describe a landscape scale modeling approach designed to examine the relationship between potential chloride contamination in wetlands and patterns of oil and gas development. We used a spatial Bayesian hierarchical modeling approach to assess multiple models explaining chloride concentrations in wetlands. These models included effects related to oil and gas wells (e.g. age of wells, number of wells) and surficial geology (e.g. glacial till, outwash). We found that the model containing the number of wells and the surficial geology surrounding a wetland best explained variation in chloride concentrations. Our spatial predictions showed regions of localized high chloride concentrations. Given the spatiotemporal variability of regional wetland water chemistry, we do not regard our results as predictions of contamination, but rather as a way to identify locations that may require more intensive sampling or further investigation. We suggest that an approach like the one outlined here could easily be extended to more of an adaptive monitoring approach to answer questions about chloride contamination risk that are of interest to managers.

  17. Changes in the Precambrian ocean U cycle linked to the evolution of surficial redox conditions

    Science.gov (United States)

    Partin, C. A.; Bekker, A.; Scott, C.; Gill, B. C.; Lyons, T. W.

    2009-12-01

    The rise of atmospheric oxygen between 2.47 and 2.32 Ga undoubtedly had a significant impact on global biogeochemical cycles and particularly, the intensity of oxidative continental weathering. While the timing of atmospheric oxygenation is well-constrained, the redox -state of the deep ocean throughout the Proterozoic is less known. The distribution of redox-sensitive elements, such as uranium and molybdenum, in ancient sedimentary rocks provides insight into the response of the deep ocean to this dramatic geochemical change. Here we present a compilation of U concentrations in marine black shales, from the Archean to the present to track the coupled redox evolution of the atmosphere and oceans, and to decipher changes in the uranium cycle itself. Since riverine delivery represents the only significant source of uranium to the oceans, and scavenging by organic matter-rich sediments beneath suboxic to anoxic waters represents the only significant sink, uranium concentrations in black shales hold a record of the evolution of the uranium cycle through time. Temporal changes in the concentrations of U in black shales can be attributed to two first-order controls: variable delivery of riverine U to the ocean, a reflection of levels of oxygen in the atmosphere, and the extent of ocean anoxic conditions. The compiled data show a series of changes in the uranium cycle through time. Phanerozoic uranium enrichments are associated with ocean-wide anoxic events coupled with a fully developed oxidative continental weathering cycle. Enrichments are muted in Proterozoic sediments, reflecting either a weaker riverine delivery of uranium to the oceans, and/or a strong sink associated with widespread anoxia. Authigenic uranium enrichments significantly above crustal levels, which reflect strong oxidative continental weathering, do not appear until several hundred million years after the Great Oxidation Event. We propose that the U cycle in the Archean oceans was dominated by the

  18. Negative effects of excessive soil phosphorus on floristic quality in Ohio wetlands

    Science.gov (United States)

    Stapanian, Martin A.; Schumacher, William; Gara, Brian; Monteith, Steve

    2016-01-01

    Excessive soil nutrients, often from agricultural runoff, have been shown to negatively impact some aspects of wetland plant communities. We measured plant-available phosphorus (Mehlich-3: MeP) in soil samples, and assessed the vascular plant community and habitat degradation at 27 emergent and 13 forested wetlands in Ohio, USA. We tested two hypotheses: (1) that an index of vegetation biological integrity based on floristic quality was lower in wetlands with higher concentrations of MeP in the soil, and (2) that higher concentrations of MeP occurred in wetlands with more habitat degradation (i.e., lower quality), as estimated by a rapid assessment method. Hypothesis (1) was supported for emergent, but not for forested wetlands. Hypothesis (2) was marginally supported (P = 0.09) for emergent, but not supported for forested wetlands. The results indicate that the effect of concentration of phosphorus in wetland soils and the quality of plant species assemblages in wetlands is more complex than shown in site-specific studies and may depend in part on degree of disturbance in the surrounding watershed and dominant wetland vegetation type. Woody plants in forested wetlands are typically longer lived than herbaceous species in the understory and emergent wetlands, and may persist despite high inputs of phosphorus. Further, the forested wetlands were typically surrounded by a wide band of forest vegetation, which may provide a barrier against sedimentation and the associated phosphorus inputs to the wetland interior. Our results indicate that inferences about soil nutrient conditions made from rapid assessment methods for assessing wetland habitat condition may not be reliable.

  19. Negative effects of excessive soil phosphorus on floristic quality in Ohio wetlands.

    Science.gov (United States)

    Stapanian, Martin A; Schumacher, William; Gara, Brian; Monteith, Steven E

    2016-05-01

    Excessive soil nutrients, often from agricultural runoff, have been shown to negatively impact some aspects of wetland plant communities. We measured plant-available phosphorus (Mehlich-3: MeP) in soil samples, and assessed the vascular plant community and habitat degradation at 27 emergent and 13 forested wetlands in Ohio, USA. We tested two hypotheses: (1) that an index of vegetation biological integrity based on floristic quality was lower in wetlands with higher concentrations of MeP in the soil, and (2) that higher concentrations of MeP occurred in wetlands with more habitat degradation (i.e., lower quality), as estimated by a rapid assessment method. Hypothesis (1) was supported for emergent, but not for forested wetlands. Hypothesis (2) was marginally supported (P=0.09) for emergent, but not supported for forested wetlands. The results indicate that the effect of concentration of phosphorus in wetland soils and the quality of plant species assemblages in wetlands is more complex than shown in site-specific studies and may depend in part on degree of disturbance in the surrounding watershed and dominant wetland vegetation type. Woody plants in forested wetlands are typically longer lived than herbaceous species in the understory and emergent wetlands, and may persist despite high inputs of phosphorus. Further, the forested wetlands were typically surrounded by a wide band of forest vegetation, which may provide a barrier against sedimentation and the associated phosphorus inputs to the wetland interior. Our results indicate that inferences about soil nutrient conditions made from rapid assessment methods for assessing wetland habitat condition may not be reliable.

  20. Neotropical coastal wetlands

    Science.gov (United States)

    McKee, Karen L.; Batzer, Darold P.; Baldwin, Andrew H.

    2012-01-01

    The Neotropical region, which includes the tropical Americas, is one of the world's eight biogeographic zones. It contains some of the most diverse and unique wetlands in the world, some of which are still relatively undisturbed by humans. This chapter focuses on the northern segment of the Neotropics (south Florida, the Caribbean islands, Mexico, and Central America), an area that spans a latitudinal gradient from about 7 N to 29 N and 60 W to 112 W. Examples of coastal wetlands in this realm include the Everglades (Florida, USA), Ten Thousand Islands (Florida, USA), Laguna de Terminos (Mexico), Twin Cays (Belize), and Zapata Swamp (Cuba). Coastal wetlands are dominated by mangroves, which will be emphasized here, but also include freshwater swamps and marshes, saline marshes, and seagrass beds. The aim of this chapter is to provide a broad overview of Neotropical coastal wetlands of the North American continent, with an emphasis on mangroves, since this is the dominant vegetation type and because in-depth coverage of all wetland types is impossible here. Instead, the goal is to describe the environmental settings, plant and animal communities, key ecological controls, and some conservation concerns, with specific examples. Because this book deals with wetlands of North America, this chapter excludes coastal wetlands of South America. However, much of the information is applicable to mangrove, marsh, and seagrass communities of other tropicaI regions.

  1. Sustainable wetland management and support of ecosystem services

    Science.gov (United States)

    Smith, Loren M.; Euliss, Ned H.; Wilcox, Douglas A.; Brinson, Mark M.

    2009-01-01

    This article is a follow-up on a previous piece in the National Wetlands Newsletter in which we outlined problems associated with a static, local approach to wetland management versus an alternative that proposes a temporal and geomorphic approach (Euliss et al. 2009). We extend that concept by drawing on companion papers recently published in the journal Wetlands (Euliss et al. 2008, Smith et al. 2008). Here we highlight reasons for the failure of many managed wetlands to provide a suite of ecosystem services (e.g., carbon storage, diodiversity, ground-water recharge, contaminant filtering, floodwater storage). Our principal theme is that wetland management is best approached by giving consideration to the hydrogeomorphic processes that maintain productive ecosystems and by removing physical and social impediments to those processes. Traditional management actions are often oriented toward maintaining static conditions in wetlands without considering the temporal cycles that wetlands need to undergo or achieve productivity for specific groups of wildlife, such as waterfowl. Possibly more often, a manager's ability to influence hydrogeomorphic processes is restricted by activities in surrounding watersheds. These could be dams, for example, which do not allow management of flood-pulse processes essential to productivity of riparian systems. In most cases, sediments and nutrients associated with land use in contributing watersheds complicate management of wetlands for a suite of services, including wildlife. Economic or policy forces far-removed from a wetland often interact to prevent occurrence of basic ecosystem processes. Our message is consistent with recommendation of supply-side sustainability of Allen et al. (2002) in which ecosystems are managed "for the system that produces outputs rather than the outputs themselves."

  2. Isotopic Fractionation of Selenium Oxyanions in Wetlands

    Science.gov (United States)

    Clark, S. K.; Johnson, T. M.

    2004-05-01

    As oxic surface waters pass through aquatic macrophytes and over anoxic sediments in wetlands and lakes, the dissolved Se load often decreases; and, Se isotope ratio measurements can provide information about the mechanisms involved. Previous work on microbially induced isotopic fractionation of Se oxyanions under nearly natural conditions using wetland sediments shows consistent Se isotopic shifts during reduction of Se(VI) and Se(IV) to insoluble Se(0). However, previous isotopic studies of total dissolved selenium in wetlands found little to no isotopic shift as dissolved selenium concentrations decreased. This suggests that plant/algal uptake, followed by deposition and degradation, is the primary route of Se transfer into sediments. However, it is possible that the effective isotopic fractionation between Se in the surface water and Se deposited into sediments is somehow much less than the fractionation induced by the reduction reaction, or that cycling of organically bound Se is involved. In this study, we report Se isotope data for Se(VI), Se(IV) and total dissolved Se, Se(T), in surface waters from three wetland/lake sites: Sweitzer Lake, CO; 33-Mile Reservoir, WY; and, a small pond adjacent to Benton Lake, MT. We isolated Se(IV) via hydride generation, and Se(VI) via ion exchange. Se(T), including any organic components, was also analyzed. Isotope analysis was performed on an Isoprobe MC-ICPMS, using a method modified from that of Rouxel et al. (2002). We used the 82Se + 74Se double spike approach, and spiked samples before species separation. Our results for all three locations indicate similar trends in concentration changes and isotopic shifts between the inflow and outflow waters. Se(T) concentrations decrease by 45-70%, and Se(VI) concentrations decrease by 60-90%, whereas Se(IV) concentrations increase by 60-150%. Concomitant 80Se/76Se shifts are +0.5-0.8‰ for Se(T); -0.1-0.5‰ for Se(VI); and +0.4-6.5‰ for Se(IV). These data provide greater

  3. Impact of Different Land Use Modes on Nutrients of Sediments from Mangrove Wetlands of China%土地利用方式改变对红树林沉积物中营养元素含量的影响

    Institute of Scientific and Technical Information of China (English)

    袁彦婷; 丁振华; 张玲; 龙江平; 卢豪良; 刘洋; 潘家永

    2012-01-01

    以广西、广东、海南等地代表性红树林湿地为对象,研究红树林湿地利用方式的改变对沉积物有机碳、总硫、总氮和总磷等营养元素的含量变化和影响,结果表明:1)广东和海南红树林区总氮和总磷变化相似,均为:沉积物〉农田〉鱼塘〉光滩,广西大冠沙稍有不同,光滩的氮磷含量最低;有机碳和总硫含量各地稍有差异,但是红树林沉积物中的有机碳,总硫含量普遍高于当地光滩、鱼塘和农田土壤,并且以光滩的土壤营养元素含量最低。2)根据广东、广西、海南主要红树林区推算全国红树林区土地利用方式的改变后土壤有机碳、总硫、总氮、总磷的损失量分别为3.05×1012 g、2.68×1011 g、2.94×1012 g和0.377×1011 g。说明土地利用与土地覆被的变化加剧了土壤有机碳、硫、氮磷的流失,导致原红树林区土壤逐渐贫瘠。%This study aims at evaluating impacts of mangrove wetland-use on the levels of organic carbon,total surfer,total nitrogen and total phosphorus in sediments from major mangrove wetland ecosystems in Guangxi Autonomous Region,Guangdong and Hainan Island,China.Our results show that: 1) both Guangdong and Hainan displayed the same pattern for total nitrogen and total phosphorus,decreasing in the order of sediment farmland pond mudflat;within a slightly different order,the lowest levels for total nitrogen and total phosphorus were also observed in the mudflat of Guangxi Daguansha mangrove wetland.As to the concentrations of organic carbon and total surfer,although a slight difference was detected,all the three districts exhibited greater values in mangrove sediments,with the levels of mudflat being the lowest;2) based on loss amounts from Guangdong,Guangxi and Hainan,we further calculated the nationwide loss amounts of organic carbon,total sulfur,nitrogen and phosphorus(3.05×1012 g,2.68×1011 g,2.94×1012 g and 0.377×1011 g,respectively) and it

  4. Aquatic macrophytes can be used for wastewater polishing but not for purification in constructed wetlands

    Science.gov (United States)

    Tang, Yingying; Harpenslager, Sarah F.; van Kempen, Monique M. L.; Verbaarschot, Evi J. H.; Loeffen, Laury M. J. M.; Roelofs, Jan G. M.; Smolders, Alfons J. P.; Lamers, Leon P. M.

    2017-02-01

    The sequestration of nutrients from surface waters by aquatic macrophytes and sediments provides an important service to both natural and constructed wetlands. While emergent species take up nutrients from the sediment, submerged and floating macrophytes filter nutrients directly from the surface water, which may be more efficient in constructed wetlands. It remains unclear, however, whether their efficiency is sufficient for wastewater purification and how plant species and nutrient loading affects nutrient distribution over plants, water and sediment. We therefore determined nutrient removal efficiencies of different vegetation (Azolla filiculoides, Ceratophyllum demersum and Myriophyllum spicatum) and sediment types (clay, peaty clay and peat) at three nutrient input rates, in a full factorial, outdoor mesocosm experiment. At low loading (0.43 mg P m-2 d-1), plant uptake was the main pathway (100 %) for phosphorus (P) removal, while sediments showed a net P release. A. filiculoides and M. spicatum showed the highest biomass production and could be harvested regularly for nutrient recycling, whereas C. demersum was outcompeted by spontaneously developing macrophytes and algae. Higher nutrient loading only stimulated A. filiculoides growth. At higher rates ( ≥ 21.4 mg P m-2 d-1), 50-90 % of added P ended up in sediments, with peat sediments becoming more easily saturated. For nitrogen (N), 45-90 % was either taken up by the sediment or lost to the atmosphere at loadings ≥ 62 mg N m-2 d-1. This shows that aquatic macrophytes can indeed function as an efficient nutrient filter but only for low loading rates (polishing) and not for high rates (purification). The outcome of this controlled study not only contributes to our understanding of nutrient dynamics in constructed wetlands but also shows the differential effects of wetland sediment types and plant species. Furthermore, the acquired knowledge may benefit the application of macrophyte harvesting to remove

  5. Constructed wetlands as a component of the agricultural landscape: Mitigation of herbicides in simulated runoff from upland drainage areas

    Science.gov (United States)

    Constructed wetlands are a recommended practice for buffering pollutant source areas and receiving waters. A wetland consisting of a sediment trap and two treatment cells was constructed in a Mississippi Delta lake watershed. A 3-h simulated runoff event was initiated (2003) to evaluate fate and tr...

  6. Hydrogeologic characterization and assessment of bioremediation of chlorinated benzenes and benzene in wetland areas, Standard Chlorine of Delaware, Inc. Superfund Site, New Castle County, Delaware, 2009-12

    Science.gov (United States)

    Lorah, Michelle M.; Walker, Charles W.; Baker, Anna C.; Teunis, Jessica A.; Majcher, Emily H.; Brayton, Michael J.; Raffensperger, Jeff P.; Cozzarelli, Isabelle M.

    2014-01-01

    Wetlands at the Standard Chlorine of Delaware, Inc. Superfund Site (SCD) in New Castle County, Delaware, are affected by contamination with chlorobenzenes and benzene from past waste storage and disposal, spills, leaks, and contaminated groundwater discharge. In cooperation with the U.S. Environmental Protection Agency, the U.S. Geological Survey began an investigation in June 2009 to characterize the hydrogeology and geochemistry in the wetlands and assess the feasibility of monitored natural attenuation and enhanced bioremediation as remedial strategies. Groundwater flow in the wetland study area is predominantly vertically upward in the wetland sediments and the underlying aquifer, and groundwater discharge accounts for a minimum of 47 percent of the total discharge for the subwatershed of tidal Red Lion Creek. Thus, groundwater transport of contaminants to surface water could be significant. The major contaminants detected in groundwater in the wetland study area included benzene, monochlorobenzene, and tri- and di-chlorobenzenes. Shallow wetland groundwater in the northwest part of the wetland study area was characterized by high concentrations of total chlorinated benzenes and benzene (maximum about 75,000 micrograms per liter [μg/L]), low pH, and high chloride. In the northeast part of the wetland study area, wetland groundwater had low to moderate concentrations of total chlorinated benzenes and benzene (generally not greater than 10,000 μg/L), moderate pH, and high sulfate concentrations. Concentrations in the groundwater in excess of 1 percent of the solubility of the individual chlorinated benzenes indicate that a contaminant source is present in the wetland sediments as dense nonaqueous phase liquids (DNAPLs). Consistently higher contaminant concentrations in the shallow wetland groundwater than deeper in the wetland sediments or the aquifer also indicate a continued source in the wetland sediments, which could include dissolution of DNAPLs and

  7. Wetlands Inventory Nevada

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Nevada wetlands inventory is a unit of a nationwide survey undertaken by the Fish and Wildlife Service to locate and tabulate by habitat types the important...

  8. WaterWetlands_NWI

    Data.gov (United States)

    Vermont Center for Geographic Information — VCGI downloaded NWI quads from the US FWS web site and reprojected to VCS NAD83. NWI digital data files are records of wetlands location and classification as...

  9. Classics of Artifical Wetland

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    By the construcfion of frraced fields over the past cenfuries,the Hani people created wetland in the ailao Mountains,an area where there originally was no such land ,which greatly improved the local ecosystem.

  10. VEGETATION MAPPING IN WETLANDS

    Directory of Open Access Journals (Sweden)

    F. PEDROTTI

    2004-01-01

    Full Text Available The current work examines the main aspects of wetland vegetation mapping, which can be summarized as analysis of the ecological-vegetational (ecotone gradients; vegetation complexes; relationships between vegetation distribution and geomorphology; vegetation of the hydrographic basin lo which the wetland in question belongs; vegetation monitoring with help of four vegetation maps: phytosociological map of the real and potential vegetation, map of vegetation dynamical tendencies, map of vegetation series.

  11. History through sediments: environmental, land use and technological change in the record of a temperate wetland (Las Tablas de Daimiel, central Spain); La historia a traves de los sedimentos: cambios climaticos y de uso del suelo en el registro reciente de un humedal mediterraneo (Las Tablas de Daimiel, Ciudad Real)

    Energy Technology Data Exchange (ETDEWEB)

    Santisteban, J. I.; Mediavilla, R.; Gil Garcia, M. J.; Dominguez Castro, F.; Ruiz Zapata, M. B.

    2009-07-01

    The analysis of the sediments of a temperate wetland in central Spain (Las Tablas de Daimiel National Park) and their correlation to historical and documental data allows to interpret the environmental changes recorded in such sediments as due to the variable intensity human action in addition to the natural variability. Recorded events are related to land use changes that are caused by the socio economical circumstances of the surrounding human communities. Relative intensity and length of such impacts permits to estimate the duration of the anthropic events and the recovery ability of the natural system, evidencing that the intensity degree is determined by the technological capability to sustain a prolonged soil use. As a result, the Tablas de Daimiel National Park record has been divided in three periods: a natural period, when the impact of events is short and the environment is able to recover quickly, a pre industrial period, when changes are gradual but sustained, and an industrial period, when the sustained activity is so intense that the natural system is unable to recover. (Author) 34 refs.

  12. Toxicity of stormwater treatment pond sediments to Hyallela azteca (Amphipoda)

    Science.gov (United States)

    Karouna-Renier, N.K.; Sparling, D.W.

    1997-01-01

    Stormwater wetlands are created to contain runoff from human developments and are designed to retain contaminants such as heavy metals, petroleum hydrocarbons, silt, pesticides, and nutrients before the runoff enter natural waterways. Because of this design, stormwater wetlands have a potential of becoming toxic sinks to organisms utilizing the wetlands for habitat. We conducted a 10-day sediment bioassay on Hyallela azteca as part of a larger study on the possible hazards of stormwater wetlands to aquatic invertebrates. Water and sediments from 10 wetlands separated into reference, residential, commercial, and highway land uses were used. No differences in survival were observed among land use categories, possibly because the ratio of acid volatile sulfides/simultaneously extractable metals (AVS/SEM) was > 1.0 for all of the ponds tested; values > 1 in this ratio are indications that toxic metals may not be bioavailable. Survival and growth rates correlated positively with AVS.

  13. 北部湾北部滨海湿地水体和表层沉积物中营养元素分布与污染评价%Nutrients Distribution and Contamination Assessment in Seawater and Surface Sediment of the Coastal Wetlands, Northern Beibu Gulf

    Institute of Scientific and Technical Information of China (English)

    甘华阳; 张顺之; 梁开; 林进清; 郑志昌

    2012-01-01

    Coastal wetlands have important ecological service functions in reducing nutrients into the sea and diminishing eutrophication of the estuaries. But the input of nitrogen and phosphorous to the costal wetlands in China has increased significantly with the economic development of coastal areas in these years. The induced seawater eutrophication and sediment contamination have caused negative impacts on fishery resources, human health and seawater utilization. The content, distributions and contamination status of nutrients in seawater and surface sediment of the coastal wetlands, northern Beibu Gulf (with water depth less than 6 m) are analyzed and assessed based on the investigation data obtained in April and May, 2009. The results indicated that the surface sediment in the eastern study area, bounded by Dafeng River estuary, is sandy deposit; while salty and clayey sediment dominated in the western part. The mean contents of dissolved inorganic nitrogen (DIN, including NO-3-N, NO-2-N, NH4+-N), PO43- -P and CODMn in the seawater were (211.84± 37.44) mg/L, (11.01±12.11) mg/L and (0.92±0.32) mg/L. The mean contents of total nitrogen (TN), total phosphorus (TP) and total organic carbon (TOC) in the surface sediments were (373±355) mg/g, (232.28±157.34) mg/g and (0.45±0.46)%, respectively. Medium to strong positive correlations exsit among the nutrients in the seawater or surface sediment, suggesting these nutrient elements originate from similar sources. High contents of DIN and PO43--P distributes in the sea area of Maowei sea and eastern part of Lianzhou bay. It is speculated to be caused by the large scale aquacuture developed in these areas. However, chemical oxygen demand (COD) content showed decreasing seaward. Seawater eutrophication in the area of Maowei sea and eastern part of Lianzhou bay was evaluated serious employing the method of eutrophication index. The contents of TN, TP and TOC in the surface sediments were controled clearly by particle size

  14. [Research progress on wetland ecotourism].

    Science.gov (United States)

    Wang, Li-Long; Lu, Lin

    2009-06-01

    Wetland is rich in biodiversity and cultural diversity, possessing higher tourism value and environmental education and community participation functions. Wetland ecotourism reflects the sustainable development of tourism economy and wetland protection, having received great concern from governments and scholars at home and abroad. This paper summarized the related theories and practices, discussed the research advances in wetland ecotourism from the aspects of significance, progress, contents, methods and results, and pointed out the important research fields in the future, aimed to accelerate the development of wetland ecotourism research and to provide reference about the resources exploitation, environment protection, and scientific administration of wetland and related scenic areas.

  15. Triclosan removal in wetlands constructed with different aquatic plants.

    Science.gov (United States)

    Liu, Jianing; Wang, Jingmin; Zhao, Congcong; Hay, Anthony G; Xie, Huijun; Zhan, Jian

    2015-10-22

    Triclosan (TCS) is widely used in consumer products as an antimicrobial agent. Constructed wetlands have the potential for TCS removal, but knowledge about the relative importance of sediment, plants, and microbes is limited. TCS removal performance was investigated in well-operated constructed wetlands planted with three different types of aquatic plants: emergent Cattail (C-T), submerged Hornwort (H-T), and floating Lemnaminor (L-T). Results showed that the TCS removal efficiencies from water were all greater than 97 %. Maximal TCS adsorption to sediment in the C-T wetland (13.8 ± 0.6 ng/g) was significantly lower than in the H-T wetland (21.0 ± 0.3 ng/g) or the L-T wetland (21.4 ± 0.6 ng/g). The maximal TCS concentrations in plants were 5.7 ± 0.2 and 7.2 ± 0.5 μg/g for H-T and L-T, respectively, and it was below the minimal detection limit (MDL) in C-T. Deep 16S rRNA gene sequencing results revealed that C-T wetland had the highest community richness and diversity. Some bacteria, like beta-Proteobacteria, gamma-Proteobacteria, and Bacteroidetes were detected and might have significant correlations with TCS degradation. Overall, with regard to soils, plants, and microorganism, accumulation in sediment and plants in H-T and L-T was high, while in C-T biodegradation likely played an important role.

  16. On the use of photothermal techniques for monitoring constructed wetlands

    Science.gov (United States)

    Gatts, C. E. N.; Faria, R. T.; Vargas, H.; Lannes, L. S.; Aragon, G. T.; Ovalle, A. R. C.

    2003-01-01

    Wetlands are a valued part of landscapes throughout the world. The steady increase of industrial facilities and disorganized urbanization processes, especially in developing countries, became a serious menace to these systems. The capability of wetlands to serve as a sink for nonpoint pollutants, particularly nutrients, is remarkable, but not limitless. For this reason, efforts to preserve them are considered a strategic issue for several countries. In addition, due to the exploding costs for sewage treatment, constructed wetlands for wastewater treatment (reed-bed systems) have been widely used under a variety of different conditions. Wetlands present unique characteristics related to biogeochemical cycles, the transport and transformation of chemicals due to interrelated physical, and chemical, and biological processes. Particularly, vegetated wetlands can act as a source for greenhouse gases through the emission of sediment-produced methane (CH4) to atmosphere. From studies concerning the behavior of Salvinia auriculata Aublet., we intend to demonstrate the potential use of photothermal techniques for monitoring gaseous emissions in wetlands.

  17. Metro Multnomah Wetlands - Multnomah Channel Wetland Restoration Monitoring Project

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Multnomah Channel Wetland Restoration Monitoring Project characterizes wetlands use by juvenile salmonids and other fishes in the Multnomah Channel Marsh Natural...

  18. Wetlands & Deepwater Habitats - MO 2012 East West Gateway Wetlands (SHP)

    Data.gov (United States)

    NSGIC State | GIS Inventory — Cowardin’s Classification of Wetlands and Deep Water Habitats of the United States (http://www.npwrc.usgs.gov/resource/wetlands/classwet/index.htm), together with...

  19. Wetlands & Deepwater Habitats - MO 2012 East West Gateway Wetlands (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Cowardin’s Classification of Wetlands and Deep Water Habitats of the United States (http://www.npwrc.usgs.gov/resource/wetlands/classwet/index.htm), together with...

  20. High rates of denitrification and nitrate removal in cold seep sediments.

    Science.gov (United States)

    Bowles, Marshall; Joye, Samantha

    2011-03-01

    We measured denitrification and nitrate removal rates in cold seep sediments from the Gulf of Mexico. Heterotrophic potential denitrification rates were assayed in time-series incubations. Surficial sediments inhabited by Beggiatoa exhibited higher heterotrophic potential denitrification rates (32 μM N reduced day(-1)) than did deeper sediments (11 μM N reduced day(-1)). Nitrate removal rates were high in both sediment horizons. These nitrate removal rates translate into rapid turnover times (cold seeps and the requirement for novel mechanisms to provide nitrate to the sediment microbial community.

  1. Wetland InSAR

    Science.gov (United States)

    Wdowinski, S.; Kim, S.; Amelung, F.; Dixon, T.

    2006-12-01

    Wetlands are transition zones where the flow of water, the nutrient cycling, and the sun energy meet to produce a unique and very productive ecosystem. They provide critical habitat for a wide variety of plant and animal species, including the larval stages of many ocean fish. Wetlands also have a valuable economical importance, as they filter nutrients and pollutants from fresh water used by human and provide aquatic habitats for outdoor recreation, tourism, and fishing. Globally, many such regions are under severe environmental stress, mainly from urban development, pollution, and rising sea level. However, there is increasing recognition of the importance of these habitats, and mitigation and restoration activities have begun in a few regions. A key element in wetlands conservation, management, and restoration involves monitoring its hydrologic system, as the entire ecosystem depends on its water supply. Heretofore, hydrologic monitoring of wetlands are conducted by stage (water level) stations, which provide good temporal resolution, but suffer from poor spatial resolution, as stage station are typically distributed several, or even tens of kilometers, from one another. Wetland application of InSAR provides the needed high spatial resolution hydrological observations, complementing the high temporal resolution terrestrial observations. Although conventional wisdom suggests that interferometry does not work in vegetated areas, several studies have shown that both L- and C-band interferograms with short acquisition intervals (1-105 days) can maintain excellent coherence over wetlands. In this study we explore the usage of InSAR for detecting water level changes in various wetland environments around the world, including the Everglades (south Florida), Louisiana Coast (southern US), Chesapeake Bay (eastern US), Pantanal (Brazil), Okavango Delta (Botswana), and Lena Delta (Siberia). Our main study area is the Everglades wetland (south Florida), which is covered by

  2. Hydrogeology and Migration of Septic-Tank Effluent in the Surficial Aquifer System in the Northern Midlands Area, Palm Beach County, Florida

    Science.gov (United States)

    Miller, Wesley L.

    1992-01-01

    The northern Midlands area in Palm Beach County is an area of expected residential growth, but its flat topography, poor drainage, and near-surface marl layers retard rainfall infiltration and cause frequent flooding. Public water supplies and sewer services are not planned for the area, thus, residents must rely on domestic wells and septic tanks. The water table in the northern Midlands area is seldom more than 5 feet below land surface, and regional ground-water flows are east, southwest, and south from the north-central part of the area where ground-water levels are highest. Ground-water quality in the western part of the area and in the Loxahatchee Slough is greatly influenced by residual seawater emplaced during the Pleistocene Epoch. Chloride and dissolved-solids concentrations of ground water in the surficial aquifer system in these areas often exceed secondary drinking-water standards. Residual seawater has been more effectively flushed from the more permeable sediments elsewhere in the eastern and southwestern parts of the study area. Test at three septic-tank sites showed traces of effluent in ground water (38-92 feet from the septic tank outlets) and that near-surface marl layers greatly impede the downward migration of the effluent in the surficial aquifer system throughout the northern midlands.

  3. Microtopography enhances nitrogen cycling and removal in created mitigation wetlands

    Science.gov (United States)

    Wolf, K.L.; Ahn, C.; Noe, G.B.

    2011-01-01

    Natural wetlands often have a heterogeneous soil surface topography, or microtopography (MT), that creates microsites of variable hydrology, vegetation, and soil biogeochemistry. Created mitigation wetlands are designed to mimic natural wetlands in structure and function, and recent mitigation projects have incorporated MT as one way to attain this goal. Microtopography may influence nitrogen (N) cycling in wetlands by providing adjacent areas of aerobic and anaerobic conditions and by increasing carbon storage, which together facilitate N cycling and removal. This study investigated three created wetlands in the Virginia Piedmont that incorporated disking-induced MT during construction. One site had paired disked and undisked plots, allowing an evaluation of the effects of this design feature on N flux rates. Microtopography was measured using conventional survey equipment along a 1-m circular transect and was described using two indices: tortuosity (T), describing soil surface roughness and relief, and limiting elevation difference (LD), describing soil surface relief. Ammonification, nitrification, and net N mineralization were determined with in situ incubation of modified ion-exchange resin cores and denitrification potential was determined using denitrification enzyme assay (DEA). Results demonstrated that disked plots had significantly greater LD than undisked plots one year after construction. Autogenic sources of MT (e.g. tussock-forming vegetation) in concert with variable hydrology and sedimentation maintained and in some cases enhanced MT in study wetlands. Tortuosity and LD values remained the same in one wetland when compared over a two-year period, suggesting a dynamic equilibrium of MT-forming and -eroding processes at play. Microtopography values also increased when comparing the original induced MT of a one-year old wetland with MT of older created wetlands (five and eight years old) with disking-induced MT, indicating that MT can increase by

  4. Uranium Immobilization in Wetland Soils

    Science.gov (United States)

    Jaffe, Peter R.; Koster van Groos, Paul G.; Li, Dien; Chang, Hyun-Shik; Seaman, John C.; Kaplan, Daniel I.; Peacock, Aaron D.; Scheckel, Kirk

    2014-05-01

    In wetlands, which are a major feature at the groundwater-surface water interface, plants deliver oxygen to the subsurface to keep root tissue aerobic. Some of this oxygen leaches into the rhizosphere where it will oxidize iron that typically precipitates on or near roots. Furthermore, plans provide carbon via root exudates and turnover, which in the presence of the iron oxides drives the activity of heterotrophic iron reducers in wetland soils. Oxidized iron is an important electron acceptor for many microbially-driven transformations, which can affect the fate and transport of several pollutants. It has been shown that heterotrophic iron reducing organisms, such as Geobacter sp., can reduce water soluble U(VI) to insoluble U(IV). The goal of this study was to determine if and how iron cycling in the wetland rhizosphere affects uranium dynamics. For this purpose, we operated a series of small-scale wetland mesocosms in a greenhouse to simulate the discharge of uranium-contaminated groundwater to surface waters. The mesocosms were operated with two different Fe(II) loading rates, two plant types, and unplanted controls. The mesocosms contained zones of root exclusion to differentiate between the direct presence and absence of roots in the planted mesocosms. The mesocosms were operated for several month to get fully established, after which a U(VI) solution was fed for 80 days. The mesocosms were then sacrificed and analyzed for solid-associated chemical species, microbiological characterization, micro-X-ray florescence (µ-XRF) mapping of Fe and U on the root surface, and U speciation via X-ray Absorption Near Edge Structure (XANES). Results showed that bacterial numbers including Geobacter sp., Fe(III), as well as total uranium, were highest on roots, followed by sediments near roots, and lowest in zones without much root influence. Results from the µ-XRF mapping on root surfaces indicated a strong spatial correlation between Fe and U. This correlation was

  5. Impact of chloride on denitrification potential in roadside wetlands.

    Science.gov (United States)

    Lancaster, Nakita A; Bushey, Joseph T; Tobias, Craig R; Song, Bongkeun; Vadas, Timothy M

    2016-05-01

    Developed landscapes are exposed to changes in hydrology and water chemistry that limit their ability to mitigate detrimental impacts to coastal water bodies, particularly those that result from stormwater runoff. The elevated level of impervious cover increases not only runoff but also contaminant loading of nutrients, metals, and road salt used for deicing to water bodies. Here we investigate the impact that road salt has on denitrification in roadside environments. Sediments were collected from a series of forested and roadside wetlands and acclimated with a range of Cl(-) concentrations from 0 to 5000 mg L(-1) for 96 h. Denitrification rates were measured by the isotope pairing technique using (15)N-NO3(-), while denitrifying community structures were compared using terminal restriction fragment length polymorphism (T-RFLP) of nitrous oxide reductase genes (nosZ). Chloride significantly (p wetlands at a Cl(-) dosage of 2500 or 5000 mg L(-1), but the decrease in denitrification rates was less and not significant for the roadside wetlands historically exposed to elevated concentrations of Cl(-). The difference could not be attributed to other significant changes in conditions, such as DOC concentrations, N species concentrations, or pH levels. Denitrifying communities, as measured by T-RFs of the nosZ gene, in the roadside wetlands with elevated concentration of Cl(-) were distinctly different and more diverse compared to forested wetlands, and also different in roadside wetlands after 96 h exposures to Cl(-). The shifts in denitrifying communities seem to minimize the decrease in denitrification rates in the wetlands previously exposed to Cl. As development results in more Cl(-) use and exposure to a broad range of natural or manmade wetland structures, an understanding of the seasonal effect of Cl on denitrification processes in these systems would aid in design or mitigation of the effects on N removal rates.

  6. Wetlands Restoration Definitions and Distinctions

    Science.gov (United States)

    Ecological restoration is a valuable endeavor that has proven very difficult to define. The term indicates that degraded and destroyed natural wetland systems will be reestablished to sites where they once existed. But, what wetland ecosystems are we talki

  7. Wetland plants: biology and ecology

    National Research Council Canada - National Science Library

    Cronk, Julie K; Fennessy, M. Siobhan

    2001-01-01

    Providing a detailed account of the biology and ecology of wetland plants as well as applications of wetland plant science, this book presents a synthesis of studies and reviews from biology, plant...

  8. 1986 Wetland Plant List Nevada

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Wetland Plant List represents the combined efforts of many biologistsworking over the last 10 years to define the wetland flora of the UnitedStates.

  9. Performance of a pilot showcase of different wetland systems in an urban setting in Singapore.

    Science.gov (United States)

    Quek, B S; He, Q H; Sim, C H

    2015-01-01

    The Alexandra Wetlands, part of PUB's Active, Beautiful, Clean Waters (ABC Waters) Programme, showcase a surface flow wetland, an aquatic pond and a sub-surface flow wetland on a 200 m deck built over an urban drainage canal. Water from the canal is pumped to a sedimentation basin, before flowing in parallel to the three wetlands. Water quality monitoring was carried out monthly from April 2011 to December 2012. The order of removal efficiency is sub-surface flow (81.3%) >aquatic pond (58.5%) >surface flow (50.7%) for total suspended solids (TSS); sub-surface (44.9%) >surface flow (31.9%) >aquatic pond (22.0%) for total nitrogen (TN); and surface flow (56.7%) >aquatic pond (39.8%) >sub-surface flow (5.4%) for total phosphorus (TP). All three wetlands achieved the Singapore stormwater treatment objectives (STO) for TP removal, but only the sub-surface flow wetland met the STO for TSS, and none met the STO for TN. Challenges in achieving satisfactory performance include inconsistent feed water quality, undesirable behaviour such as fishing, release of pets and feeding of animals in the wetlands, and canal dredging during part of the monitoring period. As a pilot showcase, the Alexandra Wetlands provide useful lessons for implementing multi-objective wetlands in an urban setting.

  10. Constructed Wetlands for Wastewater Treatment

    OpenAIRE

    Jan Vymazal

    2010-01-01

    The first experiments using wetland macrophytes for wastewater treatment were carried out in Germany in the early 1950s. Since then, the constructed wetlands have evolved into a reliable wastewater treatment technology for various types of wastewater. The classification of constructed wetlands is based on: the vegetation type (emergent, submerged, floating leaved, free-floating); hydrology (free water surface and subsurface flow); and subsurface flow wetlands can be further classified accordi...

  11. Distribution and influence factors of heavy metals in surface sediments of the Yellow River Estuary wetland%黄河口湿地表层沉积物中重金属的分布特征及其影响因素

    Institute of Scientific and Technical Information of China (English)

    刘淑民; 姚庆祯; 刘月良; 单凯; 张晓晓; 陈洪涛; 于志刚

    2012-01-01

    在黄河口湿地的枯水期(2009年4月)和丰水期(2009年6月)分别采集表层沉积物样品,分析了Cu、Pb、Zn、Cr、Cd、As、Hg的含量与分布特征.结果表明,Cu、Pb、Zn、Cr、Cd、As、Hg的平均含量分别为(22.1±5.2),(53.8±7.6),(78.4±13.2),(60.5±8.9),(0.250±0.099),(7.7±2.7),(0.055±0.039)μg/g.黄河口湿地表层沉积物中重金属含量处于国内河口湿地中等水平,低于欧美发达国家河口湿地的含量.有机质的含量影响了枯水期黄河口湿地表层沉积物中重金属的含量.Cu、Zn在枯水期以及As、Hg在丰水期与细粒径颗粒物显著正相关,<16μm的细颗粒物能吸持较多的重金属.%Concentrations of heavy metal (Cu, Pb, Zn, Cr, Cd, As, Hg) were determined in the surface sediment of the Yellow River Estuary wetland during the dry (2009 April) and flood seasons (2009 June). The average concentrations of Cu, Pb, Zn, Cr, Cd, As, Hg were: (22.1±5.2), (53.8±7.6), (78.4±13.2), (60.5±8.9), (0.250±0.099), (7.7±2.7), (0.055±0.039)μg/g, respectively. The concentrations of the heavy metals were in the medium level in domestic wetlands, lower than those of the developed countries wetland in Europe and America. The distribution of heavy metals was mainly controlled by the variation of organic matter in dry season. Concentrations of CU、 Zn in dry season and As、 Hg in flood season correlated well with the fine particles.

  12. ASSESSMENT OF MERCURY IN HYPOLIMNETIC LAKE SEDIMENTS OF VERMONT AND NEW HAMPSHIRE

    Science.gov (United States)

    The research is to characterize concentrations of total methylmercury in waters and surficial sediments of Vermont and New Hampshire lakes, and to relate these data to commonly measured water column chemical parameters and watershed-level physical attributes. The primary goal of...

  13. Modeling the effect of nonuniform sediment on the dynamics of offshore tidal sandbanks

    NARCIS (Netherlands)

    Roos, Pieter C.; Wemmenhove, Rik; Hulscher, Suzanne J. M. H.; Hoeijmakers, Harry W. M.; Kruyt, N. P.

    2007-01-01

    [1] Tidal sandbanks are large-scale bed features present in many shallow shelf seas. Here we investigate the effect of nonuniform sediment on their dynamics, with a particular aim to explain observed surficial grain size variations over tidal sandbanks from a process-based modeling perspective. To t

  14. A method for using shoreline morphology to predict suspended sediment concentration in tidal creeks

    Science.gov (United States)

    Ensign, Scott; Currin, Carolyn; Piehler, Michael; Tobias, Craig

    2017-01-01

    Improving mechanistic prediction of shoreline response to sea level rise is currently limited by 1) morphologic complexity of tidal creek shorelines that confounds application of mechanistic models, and 2) availability of suspended sediment measurements to parameterize mechanistic models. To address these challenges we developed a metric to distinguish two morphodynamic classes of tidal creek and tested whether this metric could be used to predict suspended sediment concentration. We studied three small tidal creeks in North Carolina, U.S.A. We collected suspended sediment at one non-tidal and two tidal sites in each creek and measured the wetland and channel width using a geographic information system. In each creek, tidal harmonics were measured for one year, sediment accretion on the salt marsh was measured for three years, and shoreline erosion was measured from aerial photographs spanning 50 years. Additional total suspended solids measurements from seven creeks reported in a national database supplemented our analysis. Among the three intensively studied creeks, shoreline erosion was highest in the most embayed creek (having a wider channel than the width of adjoining wetlands) and lowest in the wetland-dominated creek (having a channel narrower than the width of adjoining wetlands). Wetland sediment accretion rate in the wetland-dominated creek was four times higher than the accretion in the embayed creek. The wetland-dominated tidal creek had over twice the suspended sediment as the most embayed creek. Based on these results, we conclude that our metric of embayed and contrasting wetland-dominated creek morphology provides a guide for choosing between two types of morphodynamic models that are widely used to predict wetland shoreline change. This metric also allowed us to parse the 10 tidal creeks studied into two groups with different suspended sediment concentrations. This relationship between suspended sediment concentration and creek morphology provides

  15. Physical, Chemical, Ecological, and Age Data and Trench Logs from Surficial Deposits at Hatch Point, Southeastern Utah

    Science.gov (United States)

    Goldstein, Harland L.; Miller, Mark E.; Yount, James C.; Reheis, Marith C.; Reynolds, Richard L.; Belnap, Jayne; Lamothe, Paul J.; McGeehan, John P.

    2009-01-01

    This report presents data and describes the methodology for physical, chemical and ecological measurements of sediment, soil, and vegetation, as well as age determinations of surficial deposits at Hatch Point, Canyon Rims area, Colorado Plateau, southeastern Utah. The results presented in this report support a study that examines geomorphic and soil factors that may influence boundaries between shrubland and grassland ecosystems in the study area. Shrubland ecosystems dominated by sagebrush (Artemisia tridentata) and grassland ecosystems dominated by native perennial grasses (for example, Hilaria jamesii and Sporabolis sp.) are high-priority conservation targets for the Federal Bureau of Land Management (BLM) and other resource managers because of their diversity, productivity, and vital importance as wildlife habitat. These ecosystems have been recognized as imperiled on a regional scale since at least the mid-1990s due to habitat loss (type conversions), land-use practices, and invasive exotic plants. In the Intermountain West, the exotic annual cheatgrass (Bromus tectorum) is recognized as one of the most pervasive and serious threats to the health of native sagebrush and grassland ecosystems through effects on fire regimes and resource conditions experienced by native species.

  16. Conservation of wetlands of Tanzania

    OpenAIRE

    Bakobi, B.L.M.

    1993-01-01

    The major wetland systems of Tanzania are described together with specific functions,products and attributes of lakes, rivers, swamps, estuaries, mangroves and coastal areas. Reasons and priorities for the conservation of wetlands are given together with the existingproblems of wetland conservation and their solutions.

  17. 76 FR 22785 - Wetland Conservation

    Science.gov (United States)

    2011-04-25

    ... 7 CFR Part 12 RIN 0578-AA58 Wetland Conservation AGENCY: Office of the Secretary, United States.... Background Existing wetland conservation provisions in 7 CFR part 12 require that NRCS' certification of a... Subjects in 7 CFR Part 12 Administrative practices and procedures, Soil conservation, Wetlands. For...

  18. Comprehensive Conservation Plan: Huron Wetland Management District, Madison Wetland Management District, Sand Lake Wetland Management District

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Comprehensive Conservation Plan (CCP) was written to guide management on Huron Wetland Management District, Madison Wetland Management District, and Sand Lake...

  19. Trends and causes of historical wetland loss, Sabine National Wildlife Refuge, southwest Louisiana

    Science.gov (United States)

    Bernier, Julie C.; Morton, Robert A.; Kelso, Kyle W.

    2011-01-01

    Prior U.S. Geological Survey studies (Open-File Reports 2005-1216 and 2009-1158) examined historical land- and water-area changes and estimated magnitudes of land subsidence and erosion at 10 wetland sites in the Mississippi River delta plain. The present study extends that work by analyzing interior wetland loss and relative magnitudes of subsidence and erosion at five additional wetland sites in Sabine National Wildlife Refuge (SNWR) in the western chenier plain. The study sites were selected because their geologic setting differed from that of the delta plain; also, although the refuge marshes had been managed partly to minimize wetland loss, interior wetland losses there were extensive. Historical aerial photography, datum-corrected marsh elevations and water depths, and sediment cores were integrated to evaluate historical land- and water-area changes at SNWR.

  20. Fault Growth and Propagation and its Effect on Surficial Processes within the Incipient Okavango Rift Zone, Northwest Botswana, Africa (Invited)

    Science.gov (United States)

    Atekwana, E. A.

    2010-12-01

    The Okavango Rift Zone (ORZ) is suggested to be a zone of incipient continental rifting occuring at the distal end of the southwestern branch of the East African Rift System (EARS), therefore providing a unique opportunity to investigate neotectonic processes during the early stages of rifting. We used geophysical (aeromagnetic, magnetotelluric), Shuttle Radar Tomography Mission, Digital Elevation Model (SRTM-DEM), and sedimentological data to characterize the growth and propagation of faults associated with continental extension in the ORZ, and to elucidate the interplay between neotectonics and surficial processes. The results suggest that: (1) fault growth occurs by along axis linkage of fault segments, (2) an immature border fault is developing through the process of “Fault Piracy” by fault-linkages between major fault systems, (3) significant discrepancies exits between the height of fault scarps and the throws across the faults compared to their lengths in the basement, (4) utilization of preexisting zones of weakness allowed the development of very long faults (> 25-100 km) at a very early stage of continental rifting, explaining the apparent paradox between the fault length versus throw for this young rift, (5) active faults are characterized by conductive anomalies resulting from fluids, whereas, inactive faults show no conductivity anomaly; and 6) sedimentlogical data reveal a major perturbation in lake sedimentation between 41 ka and 27 ka. The sedimentation perturbation is attributed to faulting associated with the rifting and may have resulted in the alteration of hydrology forming the modern day Okavango delta. We infer that this time period may represent the age of the latest rift reactivation and fault growth and propagation within the ORZ.