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Sample records for bay sediments chile

  1. Culturable diversity and antimicrobial activity of Actinobacteria from marine sediments in Valparaíso bay, Chile

    OpenAIRE

    Claverías, Fernanda P.; Undabarrena, Agustina; González, Myriam; Seeger, Michael; Cámara, Beatriz

    2015-01-01

    Marine-derived Actinobacteria are a source of a broad variety of secondary metabolites with diverse biological activities, such as antibiotics and antitumorals; many of which have been developed for clinical use. Rare Actinobacteria represent an untapped source of new bioactive compounds that have been scarcely recognized. In this study, rare Actinobacteria from marine sediments were isolated from the Valparaíso bay, Chile, and their potential to produce antibacterial compounds was evaluated....

  2. Culturable diversity and antimicrobial activity of Actinobacteria from marine sediments in Valparaíso bay, Chile.

    Science.gov (United States)

    Claverías, Fernanda P; Undabarrena, Agustina; González, Myriam; Seeger, Michael; Cámara, Beatriz

    2015-01-01

    Marine-derived Actinobacteria are a source of a broad variety of secondary metabolites with diverse biological activities, such as antibiotics and antitumorals; many of which have been developed for clinical use. Rare Actinobacteria represent an untapped source of new bioactive compounds that have been scarcely recognized. In this study, rare Actinobacteria from marine sediments were isolated from the Valparaíso bay, Chile, and their potential to produce antibacterial compounds was evaluated. Different culture conditions and selective media that select the growth of Actinobacteria were used leading to the isolation of 68 bacterial strains. Comparative analysis of the 16S rRNA gene sequences led to identifying isolates that belong to the phylum Actinobacteria with genetic affiliations to 17 genera: Aeromicrobium, Agrococcus, Arthrobacter, Brachybacterium, Corynebacterium, Dietzia, Flaviflexus, Gordonia, Isoptericola, Janibacter, Microbacterium, Mycobacterium, Ornithinimicrobium, Pseudonocardia, Rhodococcus, Streptomyces, and Tessaracoccus. Also, one isolate could not be consistently classified and formed a novel phylogenetic branch related to the Nocardiopsaceae family. The antimicrobial activity of these isolates was evaluated, demonstrating the capability of specific novel isolates to inhibit the growth of Gram-positive and Gram-negative bacteria. In conclusion, this study shows a rich biodiversity of culturable Actinobacteria, associated to marine sediments from Valparaíso bay, highlighting novel rare Actinobacteria, and their potential for the production of biologically active compounds.

  3. Culturable diversity and antimicrobial activity of Actinobacteria from marine sediments in Valparaíso bay, Chile

    Directory of Open Access Journals (Sweden)

    Fernanda Paz Claverías

    2015-07-01

    Full Text Available Marine-derived Actinobacteria are a source of a broad variety of secondary metabolites with diverse biological activities, such as antibiotics and antitumorals; many of which have been developed for clinical use. Rare Actinobacteria represent an untapped source of new bioactive compounds that have been scarcely recognized. In this study, rare Actinobacteria from marine sediments were isolated from the Valparaíso bay, Chile, and their potential to produce antibacterial compounds was evaluated. Different culture conditions and selective media that select the growth of Actinobacteria were used leading to the isolation of 68 bacterial strains. Comparative analysis of the 16S rRNA gene sequences led to identifying isolates that belong to the phylum Actinobacteria with genetic affiliations to 17 genera: Aeromicrobium, Agrococcus, Arthrobacter, Brachybacterium, Corynebacterium, Dietzia, Flaviflexus, Gordonia, Isoptericola, Janibacter, Microbacterium, Mycobacterium, Ornithinimicrobium, Pseudonocardia, Rhodococcus, Streptomyces and Tessaracoccus. Also, one isolate could not be consistently classified and formed a novel phylogenetic branch related to the Nocardiopsaceae family. The antimicrobial activity of these isolates was evaluated, demonstrating the capability of specific novel isolates to inhibit the growth of Gram-positive and Gram-negative bacteria. In conclusion, this study shows a rich biodiversity of culturable Actinobacteria, associated to marine sediments from Valparaíso bay, highlighting novel rare Actinobacteria, and their potential for the production of biologically active compounds.

  4. Bay sedimentation as controlled by regional crustal behaviour, local tectonics and eustatic sea-level changes: Coquimbo Formation (Miocene Pliocene), Bay of Tongoy, central Chile

    Science.gov (United States)

    Le Roux, J. P.; Olivares, Danisa M.; Nielsen, Sven N.; Smith, Norman D.; Middleton, Heather; Fenner, Juliane; Ishman, Scott E.

    2006-02-01

    The north-facing Bay of Tongoy in central Chile is flanked by topographic highs in the west and east. During the Miocene and Pliocene, the bay extended inland at least 30 km farther south than a present. It was filled with muds, sands, coquinas and gravel during a series of transgressions and regressions related to regional and local tectonic movements combined with global sea-level variations. 87Sr/ 86Sr and microfossil dating indicates transgressions between 11.9-11.2 Ma, 10.1-9.5 Ma, 9.0-7.3 Ma, 6.3-5.3 Ma, 4.3-2.2 Ma and 1.7-1.4 Ma. The regional tectonic behaviour of the crust shows general uplifting from 10.5 Ma to 6.9 Ma, associated with subduction of the Juan Fernández Ridge (JFR) beneath this part of the continent. Subsidence followed between 6.9 and 2.1 Ma, in the wake of the southeastward-migrating JFR. The subsequent subduction of an oceanic plateau similar to the JFR caused rapid uplift that led to the final emergence of the bay above sea level. The Puerto Aldea normal fault along the western limit of the study area was reactivated during the regional uplift and subsidence events, with reverse faulting occurring during the latter phase. Sporadic fault reactivation probably triggered the rapid changes in water depth reflected in the recorded vertical succession of facies.

  5. CHWAKA BAY MANGROVE SEDIMENTS, ZANZIBAR

    African Journals Online (AJOL)

    Mohammed-Studies on Benthic denitrification in the Chwaka bay mangrove. Extensive mangrove ... In this case, six sediment cores were taken randomly from the three study sites as above and a ..... Academic Press. Orlando. pp. 277-293.

  6. Delaware River and Upper Bay Sediment Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The area of coverage consists of 192 square miles of benthic habitat mapped from 2005 to 2007 in the Delaware River and Upper Delaware Bay. The bottom sediment map...

  7. Fine Sediment Resuspension Dynamics in Moreton Bay

    Institute of Scientific and Technical Information of China (English)

    YOU Zai-jin; YIN Bao-shu

    2007-01-01

    A comprehensive field study has been undertaken to investigate sediment resuspension dynamics in the Moreton Bay, a large semi-enclosed bay situated in South East Queensland, Australia. An instrumented tripod, which housed three current meters, three OBS sensors and one underwater video camera, was used to collect the field data on tides, currents, waves and suspended sediment concentrations at four sites (Sites 1, 2, 4, and 5) in the bay. Site 1 was located at the main entrance, Site 2 at the central bay in deep water, and Sites 4 and 5 at two small bays in shallow water. The bed sediment was fine sand (d50=0.2 mm) at Site 1, and cohesive sediment at the other three sites. Based on the collected field data, it is found that the dominant driving forces for sediment resuspension are a combination of ocean swell and tidal currents at Site 1, tidal currents at Site 2, and wind-waves at Sites 4 and 5. The critical bed shear stress for cohesive sediment resuspension is determined as 0.079 Pa in unidirectional flow at Site 2, and 0.076 Pa in wave-induced oscillatory flow at Site 5.

  8. Biogenic silicate accumulation in sediments, Jiaozhou Bay

    Institute of Scientific and Technical Information of China (English)

    LI Xuegang; SONG Jinming; DAI Jicui; YUAN Huamao; LI Ning; LI Fengye; SUN Song

    2006-01-01

    It has been widely recognized that low silicate content in seawater is a major limiting factor to phytoplankton primary production in Jiaozhou Bay. However the reason of Si-limitation remains poorly understood. In the present study we measured the biogenic silicate content and discussed the accumulation of silicate in Jiaozhou Bay sediment. The results show that the biogenic silica content in the sediment of the Jiaozhou Bay is obviously much higher than those in the Yellow Sea and the Bohai Sea. The BSi:TN ratios and BSi:16P ratios in the sediment are > 1 and the OC:BSi ratio in sediment is lower than these of Redfield ratio (106:16), indicating that the decomposition rate of OC is much higher than that for BSi in similar conditions. Therefore, the majority of the biogenic silicate was buried and thus did not participate in silicate recycling. Silicate accumulation in sediment may explain why Si limits the phytoplankton growth in the Jiaozhou Bay. Comparing the flux of biogenic silicate from sediments with primary production rate, it can be concluded that only 15.5% of biogenic silicate is hydrolyzed during the journey from surface to bottom in seawater, thus approximate 84.5% of biogenic silicate could reach the bottom. The silicate releasing rate from the sediment to seawater is considerably lower than that of sedimentation of biogenic silicate, indicating silicate accumulation in sediment too. In a word, the silicate accumulation in sediment is the key reason of silicate limiting to phytoplankton growth in Jiaozhou Bay.

  9. Concentración de metales pesados (Cu, Ni, Zn, Cd, Pb en la biota y sedimentos de una playa artificial, en la bahía San Jorge 23°S, norte de Chile Heavy metals concentration (Cu, Ni, Zn, Cd, Pb, in biota and sediments of an artificial beach, in San Jorge bay 23°S, northern Chile

    Directory of Open Access Journals (Sweden)

    Gabriel Castro

    2012-07-01

    Full Text Available Se evaluó el contenido de metales pesados (Cu, Ni, Zn, Cd, Pb en la biota y el sedimento de una playa artificial (Paraíso y una playa natural (El Lenguado, ubicadas en la bahía San Jorge, norte de Chile. Los resultados fueron utilizados para comparar ambos sistemas, el grado de cumplimiento de la normativa ambiental nacional e internacional, y el efecto de la construcción de la playa artificial sobre el nivel de contaminación por metales existentes históricamente en esa zona. En cada playa se ubicaron estaciones equidistantes que abarcaron desde el intermareal hasta el submareal de las cuales fueron extraídos los organismos. Se tomaron muestras de sedimento en cada playa y se determinaron las pendientes con el método de Emery. El análisis granulométrico evidenció el predominio de arena media en playa El Lenguado, y arena media y fina en playa Paraíso. El contenido de materia orgánica fue mayor en El Lenguado. En playa Paraíso se determinaron cinco phylum/superclase agrupados en 19 taxa, mientras que en El Lenguado se encontraron cuatro phylum/superclase agrupados en cc taxa. El contenido de metales en sedimentos y en la mayoría de organismos presentó valores mayores en playa Paraíso. Estos resultados, junto a las normas de calidad chilenas y norteamericanas, sugieren un evidente deterioro en la calidad ambiental de playa Paraíso lo que se demostró por un incremento en las concentraciones de estos metales desde su construcción, los que sobrepasan los límites establecidos por ambas normas.It was evaluated the heavy metal content (Cu, Ni, Zn, Cd, Pb in biota and sediment of an artificial beach (Paraíso and a natural beach (El Lenguado, both located in San Jorge bay, northern Chile. The results were used to compare both systems, the degree of fulfillment of national and international environmental regulations, and the effect of the construction of the artificial beach on the level of metal contamination historically existing in

  10. Microbial biogeography of San Francisco Bay sediments

    Science.gov (United States)

    Lee, J. A.; Francis, C. A.

    2014-12-01

    The largest estuary on the west coast of North America, San Francisco Bay is an ecosystem of enormous biodiversity, and also enormous human impact. The benthos has experienced dredging, occupation by invasive species, and over a century of sediment input as a result of hydraulic mining. Although the Bay's great cultural and ecological importance has inspired numerous surveys of the benthic macrofauna, to date there has been almost no investigation of the microbial communities on the Bay floor. An understanding of those microbial communities would contribute significantly to our understanding of both the biogeochemical processes (which are driven by the microbiota) and the physical processes (which contribute to microbial distributions) in the Bay. Here, we present the first broad survey of bacterial and archaeal taxa in the sediments of the San Francisco Bay. We conducted 16S rRNA community sequencing of bacteria and archaea in sediment samples taken bimonthly for one year, from five sites spanning the salinity gradient between Suisun and Central Bay, in order to capture the effect of both spatial and temporal environmental variation on microbial diversity. From the same samples we also conducted deep sequencing of a nitrogen-cycling functional gene, nirS, allowing an assessment of evolutionary diversity at a much finer taxonomic scale within an important and widespread functional group of bacteria. We paired these sequencing projects with extensive geochemical metadata as well as information about macrofaunal distribution. Our data reveal a diversity of distinct biogeographical patterns among different taxa: clades ubiquitous across sites; clades that respond to measurable environmental drivers; and clades that show geographical site-specificity. These community datasets allow us to test the hypothesis that salinity is a major driver of both overall microbial community structure and community structure of the denitrifying bacteria specifically; and to assess

  11. Spatial variations of mercury in sediment of Minamata Bay, Japan.

    Science.gov (United States)

    Tomiyasu, Takashi; Matsuyama, Akito; Eguchi, Tomomi; Fuchigami, Yoko; Oki, Kimihiko; Horvat, Milena; Rajar, Rudi; Akagi, Hirokatsu

    2006-09-01

    Mercury-contaminated effluent was discharged into Minamata Bay from a chemical plant over a period of approximately 40 years until 1968. In October 1977, the Minamata Bay Pollution Prevention Project was initiated to dispose of sedimentary sludge containing mercury concentrations higher than 25 mg kg(-1). In March 1990, the project was completed. In an effort to estimate current contamination in the bay, the vertical and horizontal distributions of mercury in sediment were investigated. Sediment core samples were collected on June 26, 2002 at 16 locations in Minamata Bay and Fukuro Bay located in the southern part of Minamata Bay. The sediment in Fukuro Bay had not been dredged. The total mercury concentration in surface sediment was 1.4-4.3 mg kg(-1) (2.9+/-0.9 mg kg(-1), n=9) for the dredged area of Minamata Bay and 0.3-4.8 mg kg(-1) (3.6+/-1.6 mg kg(-1), n=4) for Fukuro Bay. In the lower layers of long cores taken from both areas, the total mercury concentration decreased with depth and finally showed relatively uniform low values. These values can be considered to represent the background concentration absent of anthropogenic influence, which was estimated for the study area to be 0.068+/-0.012 mg kg(-1) (n=10). From the surface, the total mercury concentration in Fukuro Bay increased with depth and reached a maximum at 8-14 cm. In Minamata Bay, several centimeters from the surface the total mercury concentration did not change significantly having considerably higher values than the background level. At six stations, the methylmercury concentration was determined. Although the vertical variations were similar to those for total mercury, Fukuro Bay sediment showed a higher concentration of methylmercury than Minamata Bay sediment.

  12. River sediment supply, sedimentation and transport of the highly turbid sediment plume in Malindi Bay, Kenya

    Institute of Scientific and Technical Information of China (English)

    JOHNSON U.Kitheka

    2013-01-01

    The paper presents results of a study on the sediment supply and movement of highly turbid sediment plume within Malindi Bay in the Northern region of the Kenya coast.The current velocities,tidal elevation,salinity and suspended sediment concentrations (TSSC)were measured in stations located within the bay using Aanderaa Recording Current Meter (RCM-9),Turbidity Sensor mounted on RCM-9,Divers Gauges and Aanderaa Temperature-Salinity Meter.The study established that Malindi Bay receives a high terrigenous sediment load amounting to 5.7 × 106 ton·yr-1.The river freshwater supply into the bay is highly variable ranging from 7 to 680 m3·s-1.The high flows that are > 150 m3·s-1 occurred in May during the South East Monsoon (SEM).Relatively low peak flows occurred in November during the North East Monsoon (NEM) but these were usually <70 m3·s-1.The discharge of highly turbidity river water into the bay in April and May occurs in a period of high intensity SEM winds that generate strong north flowing current that transports the river sediment plume northward.However,during the NEM,the river supply of turbid water is relatively low occurring in a period of relatively low intensity NEM winds that result in relatively weaker south flowing current that transports the sediment plume southward.The mechanism of advection of the sediment plume north or south of the estuary is mainly thought to be due to the Ekman transport generated by the onshore monsoon winds.Limited movement of the river sediment plume southward towards Ras Vasco Da Gama during NEM has ensured that the coral reef ecosystem in the northern parts of Malindi Marine National Park has not been completely destroyed by the influx of terrigenous sediments.However,to the north there is no coral reef ecosystem.The high sediment discharge into Malindi Bay can be attributed to land use change in the Athi-Sabaki River Basin in addition to rapid population increase which has led to clearance of forests to open land

  13. Magnetic Characteristics of Surface Sediments of Liaodong Bay, China

    Institute of Scientific and Technical Information of China (English)

    WANG ShuangP; WANG Yonghong; LIU Jian; YU Yiyong

    2015-01-01

    Analysis of magnetic properties of marine surface sediments has been gradually proved to be one of the effective means for researching the source of marine sediments. In this paper, samples from 39 sites in Liaodong Bay were collected to analyze the magnetic characteristics of the surface sediments. Magnetic study indicated that the surface sediments of the Liaodong Bay are char-acterized by magnetite. In the middle and eastern part and the southwest corner of the Bay, the main magnetic grains were coarse multi-domain and pseudo-single-domain particles, while in other areas single-domain and pseudo-single-domain particles constitute the majority. Based on grain size and environmental magnetism data, the content of magnetic minerals has a positive correlation with the hydrodynamic environment when the magnetic mineral domain is finer. However, the content of magnetic minerals is in a complex relationship with the hydrodynamic environment in the coarse magnetic domain of magnetic minerals found in central Liaodong Bay and places outside the Fuzhou Bay, implying that the strong hydrodynamic environment accelerates the sedimentation of coarse magnetic minerals. Based on geographic pattern of magnetic properties, it can be inferred that the main provenance of the surface sediments of the Liaodong Bay is the surrounding rivers, and the comparative analysis indicates that Yellow River substances maybe also exist in the bay.

  14. Population study of the filamentous sulfur bacteria Thioploca spp. off the Bay of Concepcion, Chile

    DEFF Research Database (Denmark)

    Schulz, HN; Strotmann, B.; Gallardo, VA

    2000-01-01

    A population of filamentous sulfur bacteria Thioploca spp. living in the Bay of Concepcion, Chile, and the adjoining shelf area was sampled for 14 mo at 4 to 6 wk intervals to investigate the influence of seasonal variations in upwelling intensity and oxygen concentrations on the population...

  15. Characterization of bottom sediments from Osaka Bay, Japan

    Science.gov (United States)

    Tokunaga, S.; Hoshika, A.; Tatsumoto, H.

    1995-06-01

    The physical, chemical, and dewatering characteristics of 19 bottom sediments from Osaka Bay, Japan, have been analyzed to aid in the development of sediments in the coastal bay area. The sediments in the east near Osaka Port were highly polluted from the influence of human activities and were difficult to dewater. These sediments were composed of fine particles, low in pH, zetapotential, and initial settling rate, and were high in ignition loss, metal concentrations, compression volume, specific resistance, cake water content, and drying index. However, the sediments near Akashi Channel showed the reverse where they are affected by strong tidal current. A correlation analysis has been made of all the parameters. There are significant relationships between all the dewatering parameters. Therefore, sediments difficult to dewater by gravity settling are also difficult to dewater by vacuum filtration and solar evaporation. Sediments containing fine particles and pollutants are difficult to dewater. Several forms of pollutants can occur in the sediments.

  16. Delaware Bay, Delaware Sediment Distribution 2003 to 2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The area of coverage consists of 38 square miles of benthic habitat mapped from 2003 to 2004 along the middle to lower Delaware Bay Coast. The bottom sediment map...

  17. Sediment Thickness--Pigeon Point to South Monterey Bay, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the sediment-thickness map of the Pigeon Point to South Monterey Bay, California, region. The raster data file is included in...

  18. Sediments of Buzzards Bay acquired in 1963 (MOORE63 shapefile)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A study of bottom sediment samples from Buzzards Bay, Massachusetts, provides a basis for establishing their major depositional facies and their relationships to the...

  19. Sediment Thickness--Pigeon Point to South Monterey Bay, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the sediment-thickness map of the Pigeon Point to South Monterey Bay, California, region. The raster data file is included in...

  20. Sediments of Cape Cod Bay, Massachusetts (HOUGH42 shapefile)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Cape Cod Bay, lying on the Massachusetts coast partly enclosed by Cape Cod, is in a glaciated region of low relief. Coarse sediments generally occur in areas exposed...

  1. Composición elemental y contenido de metales en sedimentos marinos de la bahía Mejillones del Sur, Chile: evaluación ambiental de la zona costera Elemental composition and metal contents in the marine sediments of Mejillones del Sur Bay, Chile: an environmental assessment of the coastal zone

    Directory of Open Access Journals (Sweden)

    Jorge Valdés

    2009-01-01

    Full Text Available Se midió la concentración de carbono total, nitrógeno total, azufre total, materia orgánica, Ni, Cd, Pb, Cu y Zn en sedimentos costeros (10 m de profundidad de columna de agua de ocho sectores de la bahía Mejillones. La composición elemental de los sedimentos sería el resultado de la abundante materia orgánica autóctona presente en este sistema costero. El orden de abundancia de los metales analizados fue: Zn > Cu > Ni > Pb > Cd. La concentración de metales no se explicaría por el contenido de materia orgánica ni la composición granulométrica de los sedimentos costeros. La evaluación del contenido de metales en los sedimentos, mostró que el Ni, Zn y Pb estarían levemente enriquecidos en la actualidad, aún cuando los valores se mantienen dentro de un rango cercano a los niveles preindustriales. El análisis del dendrograma de similitud de los sectores de estudio separó la línea de costa de Mejillones en dos grandes zonas; una asociada a la actividad industrial desarrollada en la bahía, y otra correspondiente al área de desarrollo urbano de Mejillones con características similares a aquellos ambientes libres de actividad antrópica directa.The total carbon, total nitrogen, total sulphur, organic matter, Ni, Cd, Pb, Cu, and Zn concentrations were measured in coastal sediments (10 m water depth at eight stations in Mejillones Bay. The elemental composition of these sediments is a function of the autochthonous organic matter generated in this coastal system. The order of abundance for the metals was: Zn > Cu > Ni > Pb > Cd. The metal content is not explained by the organic matter content or grain size of these coastal sediments. The evaluation of the concentration metals in the sediments showed that Ni, Zn, and Pb are slightly enriched at the present, although with values that are similar to preindustrial concentrations. A cluster analysis of the similarity in the study area separated the Mejillones coast into two main zones

  2. Biogeochemical characteristics of nitrogen and phosphorus in Jiaozhou Bay sediments

    Institute of Scientific and Technical Information of China (English)

    LI Xuegang; SONG Jinming; YUAN Huamao; DAI Jicui; LI Ning

    2007-01-01

    Sediment samples were cored from 3 locations representing the inner bay, the outer bay and the bay mouth of Jiaozhou Bay in September 2003 to study the source and biogeochemical characteristics of nitrogen and phosphorus in the bay. The content and vertical distributions of total nitrogen (TN), total phosphorus (TP), organic nitrogen (ON), organic phosphorus (OP), inorganic nitrogen (IN), inorganic phosphorus (IP), the ratio of organic carbon and total nitrogen (OC/TN), and the ratio of total nitrogen and total phosphorus (TN/TP) in the sediments were analyzed. The results show that both TN and TP in surface sediments decrease from the inner bay to the outer bay. In general, ON occupies 50%-70% of TN and IP accounts for more than 60% of TP. In ratio of OC:TN, the nitrogen accumulated in the sediments from the inner bay and the bay mouth came mainly from terrestrial sources, and the portion of autogenetic nitrogen was 28.9% and 13.1%, respectively. However, in the outer bay, nitrogen was mainly autogenetic,accounting for 62.1% of TN, whereas phosphorus was mainly land-derived. The sedimentation fluxes of nitrogen and phosphorus varied spatially. The overall diagenesis rate of nitrogen was higher than that of phosphorus. Specifically, the diagenesis rate of OP was higher than that of IP. However, the diagenesis rate of ON was not always higher than that of IN. In species, the diagenesis rate of IN is sometimes much higher than that of the OC. In various environments, the diagenesis rate is, to some degree, affected by OC, pH, Eh, and Es.

  3. Sediment environmental capacity of 137Cs in Daya Bay

    Institute of Scientific and Technical Information of China (English)

    ZHANG Junli; CHEN Jiajun; XU Jialin; LI Yuanxin; HUANG Naiming

    2007-01-01

    Sediment environmental capacity of pollutants is very important for marine environmental management.Based on the methodology of a study on water,soil environmental capacity,and mass conservation theory in a system,the concept and model on sediment environmental capacity for 137Cs in Daya Bay were developed.The static capacity for 137Cs in the upper sediment near the shore at a shallow area was calculated,and the annual dynamic capacity and total dynamic capacity were also calculated through determination of the typical biomass in the sediment.The results showed that the estimated environmental capacity for 137Cs in sediments was approximately equal to the current input of 137Cs into the sediments.Controlling the input of 137Cs in the sediments within the environmental capacity guarantees the sustainability of the current situation of the Daya Bay ecosystem and avoidance of a significant degradation of the system.

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

    Science.gov (United States)

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

    2007-01-01

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

  5. Beach ridges U-Th dating in Tongoy bay and tectonic implications for a peninsula-bay system, Chile

    Science.gov (United States)

    Saillard, M.; Riotte, J.; Regard, V.; Violette, A.; Hérail, G.; Audin, L.; Riquelme, R.

    2012-12-01

    Along the Chilean coast, peninsulas associated with bays seem to behave as a complex system. They act as barrier to propagation of megathrust earthquakes along strike. To better understand how such a system works from ocean side to more inland, we investigated the area between the Tongoy bay and the Altos de Talinay in northern Chile (˜30°S). It represents a forearc peninsula-bay system in which a normal fault (Puerto Aldea fault) has been described as accommodating a relative vertical motion between the two parts, the peninsula being uplifted with respect to the bay. We dated shells from beach ridges by U-Th disequilibria in order to compare the bay area to the peninsula area for which 10Be dating of wave-cut platforms are available (Saillard et al., 2009). These indicate: (1) the Puerto Aldea fault activity probably ceased since at least ˜230 ka, implying the bay and peninsula parts are evolving together since then; (2) the uplift rate is variable and has decreased from ˜0.8 m/ka to ˜0.2 m/ka between ˜300 and 100 ka.

  6. Organic matter remineralization predominates phosphorus cycling in the mid-Bay sediments in the Chesapeake Bay.

    Science.gov (United States)

    Joshi, Sunendra R; Kukkadapu, Ravi K; Burdige, David J; Bowden, Mark E; Sparks, Donald L; Jaisi, Deb P

    2015-05-19

    Chesapeake Bay, the largest and most productive estuary in the U.S., suffers from varying degrees of water quality issues fueled by both point and nonpoint nutrient sources. Restoration of the Bay is complicated by the multitude of nutrient sources, their variable inputs, and complex interaction between imported and regenerated nutrients. These complexities not only restrict formulation of effective restoration plans but also open up debates on accountability issues with nutrient loading. A detailed understanding of sediment phosphorus (P) dynamics provides information useful in identifying the exchange of dissolved constituents across the sediment-water interface as well as helps to better constrain the mechanisms and processes controlling the coupling between sediments and the overlying waters. Here we used phosphate oxygen isotope ratios (δ(18)O(P)) in concert with sediment chemistry, X-ray diffraction, and Mössbauer spectroscopy on sediments retrieved from an organic rich, sulfidic site in the mesohaline portion of the mid-Bay to identify sources and pathway of sedimentary P cycling and to infer potential feedbacks on bottom water hypoxia and surface water eutrophication. Authigenic phosphate isotope data suggest that the regeneration of inorganic P from organic matter degradation (remineralization) is the predominant, if not sole, pathway for authigenic P precipitation in the mid-Bay sediments. This indicates that the excess inorganic P generated by remineralization should have overwhelmed any pore water and/or bottom water because only a fraction of this precipitates as authigenic P. This is the first research that identifies the predominance of remineralization pathway and recycling of P within the Chesapeake Bay. Therefore, these results have significant implications on the current understanding of sediment P cycling and P exchange across the sediment-water interface in the Bay, particularly in terms of the sources and pathways of P that sustain hypoxia

  7. Application of Sediment Trend Analysis in the Examination of Sediment Transport Dynamics of Missisquoi Bay

    Science.gov (United States)

    Kraft, M. P.; Manley, P.; Singer, J.; Manley, T.; McLaren, P.

    2013-12-01

    Missisquoi Bay is located between Vermont and Quebec in the northeast sector of the Restricted Arm of Lake Champlain. The average depth of the Bay is slightly less than 3 meters with a surface area covering 77.5 km2. The Bay receives water from eastern and western catchment basins, most notably via the Missisquoi, Rock, and Pike Rivers. Circulation within Missisquoi Bay has been altered by the construction of railroad causeways in the late 19th century and highway construction in the early 20th century. Over the past several decades there have also been changes in land-use practices, including the intensification of agriculture, increased animal husbandry, and urbanization. As a consequence of construction and changing land use, loadings of nitrogen and phosphorus to the Bay have increased seasonal oxygen depletion causing eutrophication. Since monitoring began in 1992, Missisquoi Bay has displayed the highest mean total phosphorus concentrations and chlorophyll a concentrations in Lake Champlain. Various efforts have taken place to reduce nutrient loading to Missisquoi Bay, but persistent release of phosphorus from bottom sediments will continue to delay for decades the recovery from nutrient diversion. To better understand the causes and timing of eutrophication in Missisquoi Bay, one component of a 5-year integrated VT EPSCoR - RACC program included an examination of N and P loadings and their distribution throughout the Bay. Internal circulation patterns are also being studied. To determine the pattern of net sediment transport and determine sediment behavior (erosion and accretion), a Sediment Trend Analysis (STA) was performed using 369 grab samples collected in the Bay. Grain size distributions for the surface sediment samples were determined using a Malvern Mastersizer 2000 particle size analyzer. Sediment maps showing the proportion of gravel, sand, and mud show that near major river distributaries sand-sized sediment was dominant with muds becoming more

  8. Nitrogen sediment fluxes in an upwelling system off central Chile (Concepción Bay and adjacent shelf during the 1997-1998 El Niño Flujos de compuestos nitrogenados desde los sedimentos, en un sistema de surgencia de Chile central (Bahía Concepción y plataforma adyacente durante El Niño 1997-1998

    Directory of Open Access Journals (Sweden)

    PRAXEDES MUÑOZ

    2004-06-01

    Full Text Available Two stations representing coastal and shelf environments (bay of Concepción and adjacent shelf, respectively were sampled in order to assess benthic nitrogen fluxes. During the study period anomalously high oxygen bottom waters conditions were observed, coinciding with the 1997-1998 El Niño event. From both sites, intact sediment cores were collected for incubation experiments to directly estimate total ammonium fluxes. Pore-water chemistry was also assessed to estimate diffusive fluxes of nitrogen compounds (NH4+, NO3- and NO2-. The NH4+ flux from incubation experiments ranged from 0.55 to 2.18 mmol m-2 day-1 in the inner bay and from 1.84 to 2.14 mmol m-2 day-1 on the shelf. NO3- diffusive fluxes to the sediments were observed in the bay in March (-17 x 10-2 mmol m-2 day-1and on the shelf in November (-2.7 x 10-2 mmol m-2 day-1, associated with the lowest NH4+ diffusive fluxes and coincident with a stronger gradient of Eh in the first centimeters of the sediments. Besides, total NH4+ fluxes lower than in normal periods were observed, suggesting the influence of less reducing conditions, consequence in turn of the lower fluxes of particulated organic material and higher dissolved oxygen in the bottom waters. These conditions were probably imposed by the El Niño event. On the other hand, and relative to previous reports, an increase of irrigation coefficients (DI was estimated. Thus, the flux extension of other nitrogen compounds could have acquired relevance in relation to NH4+ fluxes during the study periodSe analizaron los flujos de compuestos nitrogenados desde los sedimentos en dos áreas representativas de condiciones costeras y de plataforma (Bahía Concepción y plataforma adyacente, respectivamente. Durante el período de muestreo las aguas de fondo presentaron un anómalamente alto contenido de oxígeno disuelto, coincidente con el evento El Niño 1997-1998. De ambos sitios, se incubaron testigos de sedimento intactos para

  9. Predominant Nearshore Sediment Dispersal Patterns in Manila Bay

    Directory of Open Access Journals (Sweden)

    Fernando Siringan

    1997-12-01

    Full Text Available Net nearshore sediment drift patterns in Manila Bay were determined by combining the coastal geomorphology depicted in 1 : 50,000scale topographic maps and Synthetic Aperture Radar (SAR images, with changes in shoreline position and predominant longshore current directions derived from the interaction of locally generated waves and bay morphology.Manila Bay is fringed by a variety of coastal subenvironments that reflect changing balances of fluvial, wave, and tidal processes. Along the northern coast, a broad tidal-river delta plain stretching from Bataan to Bulacan indicates the importance of tides, where the lateral extent of tidal influences is amplified by the very gentle coastal gradients. In contrast, along the Cavite coast sandy strandplains, spits, and wave-dominated deltas attest to the geomorphic importance of waves that enter the bay from the South China Sea.The estimates of net sediment drift derived from geomorphological, shoreline-change, and meteorological information are generally in good agreement. Sediment drift directions are predominantly to the northeast along Cavite, to the northwest along Manila and Bulacan, and to the north along Bataan. Wave refraction and eddy formation at the tip of the Cavite Spit cause southwestward sediment drift along the coast from Zapote to Kawit. Geomorphology indicates that onshore-offshore sediment transport is probably more important than alongshore transport along the coast fronting the tidal delta plain of northern Manila Bay. Disagreements between the geomorphic-derived and predicted net sediment drift directions may be due to interactions of wave-generated longshore currents with wind- and tide-generated currents.

  10. Organic Matter Remineralization Predominates Phosphorus Cycling in the Mid-Bay Sediments in the Chesapeake Bay

    Energy Technology Data Exchange (ETDEWEB)

    Sunendra, Joshi R.; Kukkadapu, Ravi K.; Burdige, David J.; Bowden, Mark E.; Sparks, Donald L.; Jaisi, Deb P.

    2015-05-19

    The Chesapeake Bay, the largest and most productive estuary in the US, suffers from varying degrees of water quality issues fueled by both point and non–point source nutrient sources. Restoration of the bay is complicated by the multitude of nutrient sources, their variable inputs and hydrological conditions, and complex interacting factors including climate forcing. These complexities not only restrict formulation of effective restoration plans but also open up debates on accountability issues with nutrient loading. A detailed understanding of sediment phosphorus (P) dynamics enables one to identify the exchange of dissolved constituents across the sediment- water interface and aid to better constrain mechanisms and processes controlling the coupling between the sediments and the overlying waters. Here we used phosphate oxygen isotope ratios (δ18Op) in concert with sediment chemistry, XRD, and Mössbauer spectroscopy on the sediment retrieved from an organic rich, sulfidic site in the meso-haline portion of the mid-bay to identify sources and pathway of sedimentary P cycling and to infer potential feedback effect on bottom water hypoxia and surface water eutrophication. Isotope data indicate that the regeneration of inorganic P from organic matter degradation (remineralization) is the predominant, if not sole, pathway for authigenic P precipitation in the mid-bay sediments. We interpret that the excess inorganic P generated by remineralization should have overwhelmed any bottom-water and/or pore-water P derived from other sources or biogeochemical processes and exceeded saturation with respect to authigenic P precipitation. It is the first research that identifies the predominance of remineralization pathway against remobilization (coupled Fe-P cycling) pathway in the Chesapeake Bay. Therefore, these results are expected to have significant implications for the current understanding of P cycling and benthic-pelagic coupling in the bay, particularly on the

  11. Late Quaternary sedimentation in eastern Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Chauhan, O; Mascarenhas, A; Paropkari, A; Rao, Ch.M.

    This study presents variations in various size measures, calcium carbonate, organic carbon, clay mineralogy and major and trace elements in a core (5.40 m long, 2713 m depth) from the eastern Bay of Bengal. On a CM diagram, the sediments of the core...

  12. DDT residues in sediments from the Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Sarkar, A.; SenGupta, R.

    of DDT and its metabolites in the coastal sediments is attributed to the influx of huge amounts of pesticides in contaminated waters into the bay through runoff from the river along the east coast of India. Higher concentrations of DDT metabolite DDE...

  13. Sediment source fingerprinting to quantify fine sediment sources in forested catchments, Chile.

    Science.gov (United States)

    Schuller, P.; Walling, D. E.; Iroume, A.; Castillo, A.; Quilodran, C.

    2012-04-01

    A study to improve the understanding of the primary sediment sources and transfer pathways in catchments disturbed following forest plantation harvesting is being undertaken in South-Central Chile. The study focuses on two sets of paired experimental catchments (treatment and control), located about 400 km apart, with similar soil type but contrasting mean annual rainfall: Nacimiento (1,200 mm year-1) and Los Ulmos (2,500 mm year-1). Sediment source fingerprinting techniques are being used to document the primary fine sediment sources. In each catchment, three potential sediment sources were defined: clearcut slopes (Z1), forest roads (Z2) and the stream channel (Z3). In each catchment, multiple representative composite samples of the different potential source materials were collected before harvest operations from the upper 1 cm layer in Z1, Z2, and from the channel bank and bed for Z3. A time-integrating trap sampler installed in the discharge monitoring station constructed at the outlet of each catchment has been used to collect samples of the suspended sediment and these have been supplemented by sediment collected from the weir pools. Total suspended sediment load is been quantified in the monitoring stations using discharge records and integrated water sampling. Caesium-137 (137Cs), excess lead-210 (210Pbex) and other sediment properties are being used as fingerprints. After air-drying, oven-drying at 40°C and disaggregation, both the source material samples and the sediment samples collected in the discharge monitoring stations were sieved through a 63-μm sieve and the <63-μm fractions were used for subsequent analyses. For radionuclide assay, the samples were sealed in Petri dishes and after 4 weeks the mass activity density (activity concentration) of 137Cs and 210Pbex was determined by gamma analysis, using an ORTEC extended range Ge detector of 53% relative efficiency. The 137Cs and 210Pbex activity and organic carbon (Corg) concentration associated

  14. Climate Controlled Sedimentation in Maxwell Bay, King George Island, Antarctica

    Science.gov (United States)

    Hass, H.; Kuhn, G.; Wittenberg, N.; Woelfl, A.; Betzler, C.

    2012-12-01

    Climatic change in Antarctica is strongest over the Antarctic Peninsula where in places the annual mean temperatures increased by 0.5 K per decade through the past 60 years. The impact of this warming trend is clearly visible in the form of retreating glaciers and melting ice sheets, loss of sea ice and strong meltwater discharge into the coastal zone. While it is generally accepted that the rapidity of the present climate change bears a significant anthropogenic aspect, it is not clear whether the effects caused by the warming trend are exceptional and unprecedented or whether the reaction of the environment is similar to that of earlier climate phases such as the Medieval Warm Period (MWP) about 1,000 years ago. One of the major goals of the joint international research project IMCOAST is to investigate the strength of the recent warming trend and its impact on the marine environment of the West Antarctic Peninsula (WAP). The study we present here reveals the Upper Holocene climatic history based on high-resolution sediment cores from Maxwell Bay (King George Island, WAP) and information on the actual processes triggered or altered by the recent warming trend based on sedimentologic and hydroacoustic investigations in Potter Cove, a tributary fjord to Maxwell Bay. Long sediment cores from Maxwell Bay reveal grain-size changes that can be linked to cold and warm phases such as the Little Ice Age (LIA) and the MWP. Generally, warm phases are finer grained than cold phases as a result of longer and stronger melting processes during the warm phases. It is suggested that meltwater plumes carry fine-grained sediment out of the surrounding fjords into Maxwell Bay where it settles in suitable areas to produce sediments that have a modal value around 16 μm. This mode is largely absent in sediments deposited during e.g. the LIA. However, post LIA sediments are depleted in the 16 μm-mode sediment suggesting slightly different conditions during the last century. One reason

  15. Assessment of sediment contamination in Casco Bay, Maine, USA

    Energy Technology Data Exchange (ETDEWEB)

    Wade, Terry L. [Geochemical and Environmental Research Group, Texas A and M University, 833 Graham Road, College Station, TX 77845 (United States); Sweet, Stephen T. [Geochemical and Environmental Research Group, Texas A and M University, 833 Graham Road, College Station, TX 77845 (United States)], E-mail: sweet@gerg.tamu.edu; Klein, Andrew G. [Geography Department, Texas A and M University, 814B Eller O and M Building, College Station, TX 77843 (United States)

    2008-04-15

    The current status of contaminant concentrations in Casco Bay, decadal trends of these contaminants and changes in their geographical distribution are assessed using sediment samples collected approximately 10 years apart. In general, regulated contaminants appeared to be decreasing in concentration. Total PAH and dioxins/furans concentrations did not significantly change over this period. Total organochlorine pesticides, 4,4-DDE, 4,4-DDD, total DDT, PCB, tributyltin and total butyltin decreased in concentration. Trace element concentrations in sediments decreased at the majority of the sampling sites for chromium, nickel, and selenium while arsenic, cadmium, copper, lead, mercury, silver, and zinc remained relatively constant. None of the contaminants measured has increased by more than a factor of 2. Selected sites located in the Inner Bay, where concentrations are higher and new inputs were more likely, showed increased concentrations of contaminants. Most contaminants were not found at concentrations expected to adversely affect sediment biota based on ERL/ERM guidelines. - Sediment studies indicate decadal decreases for many chemical contaminants in Casco Bay.

  16. Fish larvae retention linked to abrupt bathymetry at Mejillones Bay (northern Chile during coastal upwelling events

    Directory of Open Access Journals (Sweden)

    Pablo M Rojas

    2014-11-01

    Full Text Available The influence of oceanic circulation and bathymetry on the fish larvae retention inside Mejillones Bay, northern Chile, was examined. Fish larvae were collected during two coastal upwelling events in November 1999 and January 2000. An elevated fish larvae accumulation was found near an oceanic front and a zone of low-speed currents. Three groups of fish larvae were identified: the coastal species (Engraulis ringens and Sardinops sagax, associated with high chlorophyll-a levels; larvae from the families Phosichthyidae (Vinciguerria lucetia and Myctophidae (Diogenichthys laternatus and Triphoturus oculeus, associated with the thermocline (12°C, and finally, larvae of the families Myctophidae (Diogenichthys atlanticus and Bathylagidae (Bathylagus nigrigenys, associated with high values of temperature and salinity. The presence of a seamount and submarine canyon inside Mejillones Bay appears to play an important role in the circulation during seasonal upwelling events. We propose a conceptual model of circulation and particles retention into Mejillones Bay. The assumption is that during strong upwelling conditions the flows that move along the canyon emerge in the centre of Mejillones Bay, producing a fish larvae retention zone. Understanding the biophysical interactions responsible to trap and/or concentrate particles is essential to protect these fragile upwelling ecosystems.

  17. AMS measurement of 10Be concentrations in marine sediments from Chile Trench at the TANDAR laboratory

    Science.gov (United States)

    Rodrigues, D.; Arazi, A.; Fernández Niello, J. O.; Martí, G. V.; Negri, A. E.; Abriola, D.; Capurro, O. A.; Cardona, M. A.; de Barbará, E.; Gollan, F.; Hojman, D.; Pacheco, A. J.; Samsolo, N.; Togneri, M.; Villanueva, D.

    2017-03-01

    The 10Be/9Be ratios in marine sediments samples from the Southern Chile Trench have been measured using accelerator mass spectrometry (AMS). The samples were measured at the TANDAR accelerator, where the discrimination of the 10Be radionuclides was achieved by means of a passive absorber in front of an ionization chamber. This setup along with the high voltage available, provided a complete suppression of the 10B isobar interference. The obtained values for the 10Be concentrations, of the order of 109 atoms/g, are the first 10Be measurements from the Southern Chile Trench and offer an excellent tracer to quantitatively study the recycling of sediments in Andean magmas.

  18. Sediment Resuspension by Ship Traffic in Newark Bay, New Jersey

    Science.gov (United States)

    2015-04-01

    suspended sediment plumes created by various types of vessels within Newark Bay, New Jersey. Spatial scales, total suspended solids (TSS...resuspension surveys. On this transect, the upper half of the water column had total suspended solids (TSS) concentrations in the 10 to 30 mg/l range...Jersey. Spatial scales, total suspended solids (TSS) concentration gradients, and dispersion patterns were measured by a combination of acoustic

  19. Sediment dispersal pattern in the Bay of Bengal - evidence for commencement of Bengal Fan sedimentation

    Science.gov (United States)

    Krishna, K. S.; Ismaiel, M.; Karlapati, S.; Gopala Rao, D.; Mishra, J.; D, S.

    2015-12-01

    The sediment succession in the Bay of Bengal records signatures corresponding to India-Asia collision, regional climate, and erosional processes of the Himalayan orogeny and the Indian subcontinent. The Bengal Fan - world's largest submarine fan - has been long studied to understand the link between the Himalayan tectonics and Asian monsoon climate, but early phase information of the Himalaya erosion is not retrieved from the Indian Ocean due to lack of deep-core samples. Therefore, the missing corresponding signals hampered the understanding of coupled processes between tectonics, climate and erosion. Seismic reflection profiles and industrial drill wells from the western Bay of Bengal show two different modes of sediment deposition: initially Indian peninsular rivers discharged sediments to the ocean at a rate ~20 m/m.y. until Oligocene-Miocene time (~23 Ma) with the exception of two fairly-enhanced sediment pulses from 65 to 54 and again from 34 to 23 Ma; since 23 Ma the Ganges and Brahmaputra rivers added huge volumes of sediments to the bay with variable rates range from 40 to >1000 m/m.y. Using seismic stratigraphic technique we found a distinct increase in sediment discharge (~140 m/m.y.) at 23 Ma is an important age marker for the onset of Bengal Fan sedimentation as a coupled connection between the Himalayan tectonics and Asian climate. Further rise in sedimentation rate during the period 6.8 - 0.8 Ma is surprisingly not in agreement with the decrease in sediment rate reported at ODP Leg 116 sites in the distal Bengal Fan, but coincident with the change in monsoon intensity. Here we provide well constrained ages for the growth of the Bengal Fan, which can serve as benchmark for interactions between the Himalayan exhumation and Asian climate.

  20. Sediment data collected in 2014 from Barnegat Bay, New Jersey

    Science.gov (United States)

    Bernier, Julie C.; Stalk, Chelsea, A.; Kelso, Kyle W.; Miselis, Jennifer L.; Tunstead, Rob

    2016-05-23

    In response to the 2010 Governor’s Action Plan to clean up the Barnegat Bay–Little Egg Harbor (BBLEH) estuary in New Jersey, the U.S. Geological Survey (USGS) partnered with the New Jersey Department of Environmental Protection in 2011 to begin a multidisciplinary research project to understand the physical controls on water quality in the bay. Between 2011 and 2013, USGS scientists mapped the geological and morphological characteristics of the seafloor of the BBLEH estuary using a suite of geophysical tools. However, this mapping effort included only surficial characterization of bay sediments; to verify the sub-surface geophysical data, sediment cores were required.This report serves as an archive of sedimentologic data from 18 vibracores collected from Barnegat Bay between May and August of 2014 by the U.S. Department of Agriculture Natural Resources Conservation Service (NRCS) on behalf of the USGS. The vibracores were collected in conjunction with an ongoing NRCS subaqueous soil survey for the BBLEH estuary. The data presented in this report, including descriptive core logs, core photographs, processed grain-size data, and Geographic Information System (GIS) data files with accompanying formal Federal Geographic Data Committee metadata, can be viewed or downloaded from the Data Products and Downloads page.

  1. Evaluation of older bay mud sediment from Richmond Harbor, California

    Energy Technology Data Exchange (ETDEWEB)

    Pinza, M.R.; Mayhew, H.L.; Word, J.Q.

    1996-09-01

    The older, bay mud (OBM) unit predates modem man and could act as a barrier to the downward transport of contaminants from the younger bay mud (YBM) because of its hard-packed consistency. However, its chemical and biological nature have not been well characterized. Battelle/Marine Sciences Laboratory (MSL) conducted three independent studies of OBM sediment in January 1993, January 1994, and October 1994. These studies evaluated potential chemical contamination and biological effects of OBM that could occur as a result of dredging and disposal activities. These evaluations were performed by conducting chemical analysis, solid-phase toxicity tests, suspended- particulate-phase (SPP) toxicity tests, and bioaccumulation tests on the OBM sediment. If the sediment chemistry and toxicity results showed no or minimal contamination and toxicological responses, then either the OBM could be left exposed in Richmond Harbor after dredging the YBM without leaving a source of contamination, or if the project depths necessitate, the OBM would be acceptable for disposal at an appropriate disposal site.

  2. Butiltins Compound in Seawater and Sediment of Banten Bay

    Directory of Open Access Journals (Sweden)

    Hamidah Razak

    2004-08-01

    Full Text Available bservation on butiltin (BTs compound content in seawater and sediments from Banten Bay were conducted in August 2003 and October 2003. Butiltin content including TBT, DBT and MBT on August 2003 respectively range between <2ng Sn/l, <2 to 9 ng Sn/l and < 5 to 17 ng Sn/l and on October 2003 was found respectively nd to <2 ng Sn/l, <0.5 to 12 ng Sn/g, 0.5 to 2.7 ng Sn/g and <0.5 to 2.2 ng Sn/g, and on October 2003 was found varied from <0.5 to 4.2ng Sn/g, <0.5 to 1.1ng Sn/g and <0.5 to 1 ng Sn/g. Content of TBT was found on August 2003 higher than October 03 and also the content of TBT compound in sediments was high compared to waters. It indicated that there was accumulation of TBT in sediment. The minimal risk of TBT in seaport and for marine life according to Minister of environment in Keputusan Menteri Negara Kependudukan dan Lingkungan Hidup No.51 tahun 2004 is 10 ng/l. The results showed that Banten Bay is still appropiate for seaport and marine life.

  3. Speciation and cycling of mercury in Lavaca Bay, Texas, sediments

    Energy Technology Data Exchange (ETDEWEB)

    Bloom, N.S. [Frontier Geosciences Inc., Seattle, WA (United States); Gill, G.A. [Texas A and M Univ., Galveston, TX (United States). Dept. of Oceanography; Cappellino, S. [Parametrix Inc., Houston, TX (United States); Dobbs, C.; Mcshea, L. [Aluminum Co. of America, Point Comfort, TX (United States); Driscoll, C. [Syracuse Univ., NY (United States). Dept. of Civil and Environmental Engineering; Mason, R. [Univ. of Maryland, Solomons, MD (United States). Chesapeake Bay Lab.; Rudd, J. [Freshwater Inst., Winnipeg, Manitoba (Canada). Dept. of Fisheries and Oceans

    1999-01-01

    Sediment depth profiles of total mercury (THg) and monomethylmercury (MMHg) were collected at 15 sites in an anthropogenically contaminated estuarine system (Lavaca Bay, TX). THg in the solid phase increased with depth to a maximum located at 10--30 cm, which corresponds to historic industrial discharges to the bay. MMHg in the solid phase was highest in the upper 0--3 cm of the cores, decreasing rapidly with depth. The MMHg content of the surface sediment was a narrowly constrained fraction of the total over a range of sediment types, while making up only 0.01--0.05% of THg at depth. Porewater concentrations exhibited trends similar to but more exaggerated than in the solid phase. The distribution coefficients (log K{sub d}) for inorganic Hg were similar in most samples, averaging 4.89 {+-} 0.43. The log K{sub d} for MMHg averaged 2.70 {+-} 0.78 over all sites and depths but exhibited a subsurface minimum of 2.29 {+-} 0.67 at the point of maximum dissolved Fe. A time series showed a maximum in both solid phase and porewater MMHg during the early spring, followed by a decrease throughout the remainder of the year.

  4. A survey of molecular marker compounds in sediments of San Francisco Bay, California

    Science.gov (United States)

    Hostettler, Frances D.; Rapp, John B.; Geological Survey (U.S.) Pereira, Wilfred E.; Kvenvolden, Keith A.

    1994-01-01

    An areal survey of surficial sediments in San Francisco Bay has been conducted to evaluate the presence of extractable organic compounds. Molecular marker compounds studied include hydrocarbons (PAH's), chlorinated pesticides, and other organic compounds that provide information on sources of organic input into the Bay. Fairly uniform source profiles are seen throughout the Bay. Biomarker profiles contain mature constituents indicating anthropogenic influences and extensive sediment reworking. The dominant input signatures in San Francisco Bay sediment are those of anthropogenic PAH's from combustion and other sources, and long chain n-alkanes and n-aldehydes from terrigenous vascular plants. A comparison of the sums of the combustion PAH's and the terrigenous n-alkanes shows that an anthropogenic influence is dominant in the most urban parts of the Bay close to shore, and in mid-Bay channel areas, and a terrigenous signature is dominant nearshore in San Pablo Bay and at the southernmost station in South Bay.

  5. Aliphatics hydrocarbon content in surface sediment from Jakarta Bay, Indonesia

    Science.gov (United States)

    YAzis, M.; Asia, L.; Piram, A.; Doumenq, P.; Syakti, A. D.

    2016-02-01

    Sedimentary aliphatic hydrocarbons content have been studied quantitatively and qualitatively using GC/MS method in eight coastal stations located in the Jakarta Bay, North of Jakarta, Indonesia. The total concentrations n-alkanes have ranged from 480 μg.kg-1to 1,935 μg.kg-1sediment dry weight. Several ratios (e.g. CPI24-32, NAR, TAR, Pr/Phy, n-C17/Pr, n- C18/Phyt,n-C29/n-C17, Ʃn-alkanes/n-C16LMW/HMW, Paq and TMD) were used to evaluate the possible sources of terrestrial-marine inputs of these hydrocarbons in the sediments. The various origins of aliphatic hydrocarbons were generally biogenic, including both terrigenous and marine, with an anthropogenic pyrolytic contribution (petrogenic and biogenic combustion). Two stations (G,H) were thehighest concentration and had potential risk to environment

  6. Estuarine sedimentation, sediment character, and foraminiferal distribution in central San Francisco Bay, California

    Science.gov (United States)

    Chin, John L.; Woodrow, Donald L.; McGann, Mary; Wong, Florence L.; Fregoso, Theresa; Jaffe, Bruce E.

    2010-01-01

    Central San Francisco Bay is the deepest subembayment in the San Francisco Bay estuary and hence has the largest water volume of any of the subembayments. It also has the strongest tidal currents and the coarsest sediment within the estuary. Tidal currents are strongest over the west-central part of central bay and, correspondingly, this area is dominated by sand-size sediment. Much of the area east of a line from Angel Island to Alcatraz Island is characterized by muddy sand to sandy mud, and the area to the west of this line is sandy. The sand-size sediment over west-central bay furthermore is molded by the energetic tidal currents into bedforms of varying sizes and wavelengths. Bedforms typically occur in water depths of 15-25 m. High resolution bathymetry (multibeam) from 1997 and 2008 allow for subdivision of the west-central bayfloor into four basic types based on morphologic expression: featureless, sand waves, disrupted/man-altered, and bedrock knobs. Featureless and sand-wave morphologies dominate the bayfloor of west-central bay. Disrupted bayfloor has a direct association with areas that are undergoing alteration due to human activities, such as sand-mining lease areas, dredging, and disposal of dredge spoils. Change detection analysis, comparing the 1997 and 2008 multibeam data sets, shows that significant change has occurred in west-central bay during the roughly 10 years between surveys. The surveyed area lost about 5.45 million m3 of sediment during the decade. Sand-mining lease areas within west-central bay lost 6.77 million m3 as the bayfloor deepened. Nonlease areas gained 1.32 million m3 of sediment as the bayfloor shallowed slightly outside of sand-mining lease areas. Furthermore, bedform asymmetry did not change significantly, but some bedforms did migrate some tens of meters. Gravity cores show that the area east of Angel and Alcatraz Islands is floored by clayey silts or silty sand whereas the area to the west of the islands is floored

  7. Biogeochemical characteristics of sedimenting particles in Dona Paula Bay, India

    Science.gov (United States)

    D'souza, Fraddry; Garg, Anita; Bhosle, Narayan B.

    2003-10-01

    Sedimenting particles were collected at weekly intervals from October to May during 1995-1997 at a station in the coastal waters of Dona Paula Bay on the west coast of India. Sedimenting particles were analysed for concentration and composition of total sedimented particulate matter (TPM), biogenic silica (BSi) and total neutral carbohydrates (TCHO). TPM, BSi and TCHO fluxes showed seasonal and annual variations. Fluxes of BSi showed significant correlations with the fluxes of TCHO and fucose indicating that at the study site diatoms were associated with the production of carbohydrates. However, a high content of arabinose plus xylose (˜56% of TCHO without glucose) in some samples and their negative correlations with fucose may suggest terrestrial inputs. Sedimenting particles depleted in glucose content were enriched in rhamnose, fucose, xylose, mannose and galactose. A principal component analysis based on log-normalized wt% of monosaccharides established three factors that contributed 78% of total variance. The first factor was mostly controlled by the abundance of arabinose and xylose while the second and third factors were dependent on fucose, galactose, mannose and rhamnose. Carbohydrate composition data suggest that the nature and sources of organic matter at the study site varied over the period of study.

  8. Sediment-water fluxes of mercury in Lavaca Bay, Texas

    Energy Technology Data Exchange (ETDEWEB)

    Gill, G.A. [Texas A and M Univ., Galveston, TX (United States); Bloom, N.S. [Frontier Geosciences Inc., Seattle, WA (United States); Cappellino, S. [Parametrix, Inc., Houston, TX (United States); Driscoll, C.T. [Syracuse Univ., NY (United States). Dept. of Civil and Environmental Engineering; Dobbs, C.; McShea, L. [Aluminum Co. of America, Point Comfort, TX (United States); Mason, R. [Univ. of Maryland, Solomons, MD (United States). Chesapeake Biological Lab.; Rudd, J.W.M. [Dept. of Fisheries and Oceans, Winnipeg, Manitoba (Canada). Freshwater Inst.

    1999-03-01

    The aqueous flux of inorganic Hg and monomethyl Hg from sediments to the water column was determined at several sites in Lavaca Bay, an estuary along the Texas Coast, historically impacted by Hg discharges. Diffusive fluxes were calculated at 15 sites using interstitial pore water gradients and compared to direct flux measurements obtained at two sites using benthic flux chambers. The diffusive flux of monomethyl mercury (MMHg), when modeled as a chloride species, varied over 3 orders /of magnitude from 0.2 to 1500 ng m{sup {minus}2} day{sup {minus}1}. Diffusive fluxes determined at a single site revealed that MMHg fluxes varied seasonally; maximal fluxes occurred in late winter to early spring. Flux chamber deployments at an impacted site revealed t hat MMHg was the Hg species entering the water column from sediments and the flux was not in steady-state; there was a strong diurnal signal with most of the MMHg flux occurring during dark periods. The flux of inorganic Hg was smaller and not as easily discernible by this method. The MMHg flux during the dark period was about 6 times greater than the estimated diffusional flux for MMHgCl, suggesting that biological and/or chemical processes near the sediment-water interface were strongly mediating the sediment-water exchange of MMHg.

  9. Environmental evidence of fossil fuel pollution in Laguna Chica de San Pedro lake sediments (Central Chile)

    Energy Technology Data Exchange (ETDEWEB)

    Chirinos, L. [Centro de Ciencias Ambientales EULA-Chile, Universidad de Concepcion, PO Box 160-C, Concepcion (Chile)]. E-mail: lchirin@pucp.edu.pe; Rose, N.L. [Environmental Change Research Centre, University College London, 26 Bedford Way, London WG1HOAP (United Kingdom); Urrutia, R. [Centro de Ciencias Ambientales EULA-Chile, Universidad de Concepcion, PO Box 160-C, Concepcion (Chile); Munoz, P. [Departamento de Biologia Marina, Universidad Catolica del Norte, Larrondo 1281, Coquimbo (Chile); Torrejon, F. [Centro de Ciencias Ambientales EULA-Chile, Universidad de Concepcion, PO Box 160-C, Concepcion (Chile); Torres, L. [Departamento de Botanica, Universidad de Concepcion, Concepcion (Chile); Cruces, F. [Departamento de Botanica, Universidad de Concepcion, Concepcion (Chile); Araneda, A. [Centro de Ciencias Ambientales EULA-Chile, Universidad de Concepcion, PO Box 160-C, Concepcion (Chile); Zaror, C. [Facultad de Ingenieria Quimica, Universidad de Concepcion, Concepcion (Chile)

    2006-05-15

    This paper describes lake sediment spheroidal carbonaceous particle (SCP) profiles from Laguna Chica San Pedro, located in the Biobio Region, Chile (36{sup o} 51' S, 73{sup o} 05' W). The earliest presence of SCPs was found at 16 cm depth, corresponding to the 1915-1937 period, at the very onset of industrial activities in the study area. No SCPs were found at lower depths. SCP concentrations in Laguna Chica San Pedro lake sediments were directly related to local industrial activities. Moreover, no SCPs were found in Galletue lake (38{sup o} 41' S, 71{sup o} 17.5' W), a pristine high mountain water body used here as a reference site, suggesting that contribution from long distance atmospheric transport could be neglected, unlike published data from remote Northern Hemisphere lakes. These results are the first SCP sediment profiles from Chile, showing a direct relationship with fossil fuel consumption in the region. Cores were dated using the {sup 21}Pb technique. - The lake sediment record of SCPs shows the record of fossil-fuel derived pollution in Central Chile.

  10. Polybrominated Diphenyl Ethers (PBDEs) in Concepción Bay, central Chile after the 2010 Tsunami.

    Science.gov (United States)

    Pozo, Karla; Kukučka, Petr; Vaňková, Lenka; Přibylová, Petra; Klánová, Jana; Rudolph, Anny; Banguera, Yulieth; Monsalves, Javier; Contreras, Sergio; Barra, Ricardo; Ahumada, Ramón

    2015-06-15

    PBDEs (10 congeners) were analyzed using GC-MS in superficial sediments and organisms of the Concepción Bay after the 2010 Tsunami. From all congeners analyzed PBDE-47, -99, -100 and -209 were the most frequently detected. Concentrations (ngg(-1) d.w.) in sediments for ΣPBDE-47, -99, -100 were low (0.02-0.09). However, PBDE-209 showed significantly higher values ∼20ngg(-1) d.w. This result were ∼10 times lower than those reported in a previous study of the 2010 Tsunami. The high result might be influenced by the massive urban debris dragged by the 2010 Tsunami. In organisms, concentrations of PBDE-47, -99, -100 (∼0.4ngg(-1) d.w.) were higher than those found in sediments (∼0.04ngg(-1) d.w.). Differences in PBDE pattern were also observed between different levels of the trophic food chain (primary and secondary consumers). This is the first attempt to assess the current status of Concepción Bay after the 2010 Tsunami. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Distribution and characteristics of methylmercury in surface sediment in Minamata Bay.

    Science.gov (United States)

    Matsuyama, Akito; Yano, Shinichiro; Hisano, Akihiro; Kindaichi, Michiaki; Sonoda, Ikuko; Tada, Akihide; Akagi, Hirokatsu

    2016-08-15

    This study was carried out to evaluate the present-day chemical properties of methylmercury in surface sediment in Minamata Bay where a dredging project was completed 28years ago. Present-day sediment from Minamata Bay consists of sandy silt, and the average loss-on-ignition in surface sediment was 7.0±2.3%. The average methylmercury concentrations in the upper sediment layers were significantly higher than those in the lower sediment layers. Currently, the concentrations in sediments in Minamata Bay do not exceed the Japanese regulatory standard value for mercury. The average concentration of methylmercury in Minamata Bay surface sediment was 1.74±1.0ng/g on a dry weight basis (n=107). The methylmercury concentration in Minamata Bay surface sediment was almost 16 times higher than that in surface sediment from Isahaya Bay surface sediment, which was 0.11±0.045ng/g on a dry weight basis (n=5).

  12. Chile.

    Science.gov (United States)

    1992-05-01

    The background notes on Chile provide a statistical summary of the population, geography, government, and the economy, and more descriptive text on the history, population, government, economy, defense, and foreign relations. In brief, Chile has 13.3 million Spanish Indian (Mestizos), European, and Indian inhabitants and an annual growth rate of 1.6%. 96% are literate. Infant mortality is 18/1000. 34% of the population are involved in industry and commerce, 30% in services, 19% in agriculture and forestry and fishing, 7% in construction, and 2% in mining. The major city is Santiago. The government, which gained independence in 1810, is a republic with executive, legislative, and judicial branches. There are 12 regions. There are 6 major political parties. Suffrage is universal at 18 years. Gross domestic product (GDP) is $29.2 billion. The annual growth rate is 5% and inflation is 19%. Copper, timber, fish, iron ore, nitrates, precious metals, and molybdenum are its natural resources. Agricultural products are 9% of GDP and include wheat, potatoes, corn, sugar beets, onions, beans, fruits, and livestock. Industry is 21% of GDP and includes mineral refining, metal manufacturing, food and fish processing, paper and wood products, and finished textiles. $8.3 billion is the value of exports and $7 billion of imports. Export markets are in Japan, the US, Germany, Brazil, and the United Kingdom. Chile received $3.5 billion in economic aid between 1949-85, but little in recent years. 83% live in urban centers, principally around Santiago. Congressional representation is made on the basis of elections by a unique binomial majority system. Principal government officials are identified. Chile has a diversified free market economy and is almost self-sufficient in food production. The US is a primary trading partner. 49% of Chile's exports are minerals. Chile maintains diplomatic relations with 70 countries, however, relations are strained with Argentina and Bolivia. Relations

  13. Comparison of sediment supply to San Francisco Bay from watersheds draining the Bay Area and the Central Valley of California

    Science.gov (United States)

    McKee, L.J.; Lewicki, M.; Schoellhamer, D.H.; Ganju, N.K.

    2013-01-01

    Quantifying suspended sediment loads is important for managing the world's estuaries in the context of navigation, pollutant transport, wetland restoration, and coastal erosion. To address these needs, a comprehensive analysis was completed on sediment supply to San Francisco Bay from fluvial sources. Suspended sediment, optical backscatter, velocity data near the head of the estuary, and discharge data obtained from the output of a water balance model were used to generate continuous suspended sediment concentration records and compute loads to the Bay from the large Central Valley watershed. Sediment loads from small tributary watersheds around the Bay were determined using 235 station-years of suspended sediment data from 38 watershed locations, regression analysis, and simple modeling. Over 16 years, net annual suspended sediment load to the head of the estuary from its 154,000 km2 Central Valley watershed varied from 0.13 to 2.58 (mean = 0.89) million metric t of suspended sediment, or an average yield of 11 metric t/km2/yr. Small tributaries, totaling 8145 km2, in the nine-county Bay Area discharged between 0.081 and 4.27 (mean = 1.39) million metric t with a mean yield of 212 metric t/km2/yr. The results indicate that the hundreds of urbanized and tectonically active tributaries adjacent to the Bay, which together account for just 5% of the total watershed area draining to the Bay and provide just 7% of the annual average fluvial flow, supply 61% of the suspended sediment. The small tributary loads are more variable (53-fold between years compared to 21-fold for the inland Central Valley rivers) and dominated fluvial sediment supply to the Bay during 10 out of 16 yr. If San Francisco Bay is typical of other estuaries in active tectonic or climatically variable coastal regimes, managers responsible for water quality, dredging and reusing sediment accumulating in shipping channels, or restoring wetlands in the world's estuaries may need to more carefully

  14. A summary report of sediment processes in Chesapeake Bay and watershed

    Science.gov (United States)

    Langland, Michael; Cronin, Thomas

    2003-01-01

    The Chesapeake Bay, the Nation's largest estuary, has been degraded because of diminished water quality, loss of habitat, and over-harvesting of living resources. Consequently, the bay was listed as an impaired water body due to excess nutrients and sediment. The Chesapeake Bay Program (CBP), a multi-jurisdictional partnership, completed an agreement called ?Chesapeake 2000? that revises and establishes new restoration goals through 2010 in the bay and its watershed. The goal of this commitment is the removal of the bay from the list of impaired waterbodies by the year 2010. The CBP is committed to developing sediment and nutrient allocations for major basins within the bay watershed and to the process of examining new and innovative management plans in the estuary itself and along the coastal zones of the bay. However, additional information is required on the sources, transport, and deposition of sediment that affect water clarity. Because the information and data on sediment processes in the bay were not readily accessible to the CBP or to state, and local managers, a Sediment Workgroup (SWGP) was created in 2001. The primary objective of this report, therefore, is to provide a review of the literature on the sources, transport, and delivery of sediment in Chesapeake Bay and its watershed with discussion of potential implications for various management alternatives. The authors of the report have extracted, discussed, and summarized the important aspects of sediment and sedimentation that are most relevant to the CBP and other sediment related-issues with which resources managers are involved. This report summarizes the most relevant studies concerning sediment sources, transport and deposition in the watershed and estuary, sediments and relation to water clarity, and provides an extensive list of references for those wanting more information.

  15. Chile.

    Science.gov (United States)

    1988-09-01

    Chile is a long (2650 miles), narrow (250 miles at widest point) country sandwiched between the Andes mountains and the Pacific. The northern desert is rich in copper and nitrates; the temperate middle region is agricultural and supports the major cities, including Santiago, the capital, and the port of Valparaiso; and the southern region is a cold and damp area of forests, grasslands, lakes, and fjords. The country is divided into 12 administrative regions. Chile's population of 12.5 million are mainly of Spanish or Indian descent or mestizos. Literacy is 92.3%, and the national language is Spanish. Infant mortality is 18.1/1000, and life expectancy is 68.2 years. 82% of the people are urban, and most are Roman Catholics. Chile was settled by the Spanish in 1541 and attached to the Viceroyalty of Peru. Independence was won in 1818 under the leadership of Bernardo O'Higgins. In the 1880s Chile extended its sovereignty over the Strait of Magellan in the south and areas of southern Peru and Bolivia in the north. An officially parliamentary government, elected by universal suffrage, drifted into oligarchy and finally into a military dictatorship under Carlos Ibanez in 1924. Constitutional government was restored in 1932. The Christian Democratic government of Eduardo Frei (1964-70) inaugurated major reforms, including land redistribution, education, and far-reaching social and economic policies. A Marxist government under Salvador Allende lasted from 1970 to 1973 when the present military government of General Pinochet Ugarte took power, overthrew Allende, abolished the Congress, and banned political parties. It has moved the country in the direction of a free market economy but at the cost of systematic violations of human rights. A new constitution was promulgated in 1981, and congressional elections have been scheduled for October, 1989. A "National Accord for Transition to Full Democracy" was mediated by the Catholic Church in 1985. The social reforms of the

  16. Geomorphic impact of the 16S 2015 tsunami event in the Coquimbo Bay (Northern Chile)

    Science.gov (United States)

    Abad, Manuel; Izquierdo, Tatiana; Lock, Suan-lin; Rojas, Diego; Fritis, Eduardo

    2017-04-01

    On September 16, 2105 a Mw 8.3 earthquake occurred at 22:55 GTM with a focal depth of 23 km and an epicenter located 31.570°S, W 71.670°, in the Coquimbo Region (northern Chile). This event triggered a tsunami with wave heights of more than 6 m that caused damages and flooding in the northern Chilean coast, mainly in the cities of Tongoy and Coquimbo - La Serena. The vertical run-up shows an important saw-tooth like variation due to the sharp changes in the topography, specially towards both ends of the bay. The highest and more irregular values occurred in the South sector, that presents a higher topographic gradient, and progressively decrease towards the North were the topography is flatter. The horizontal flooding reached its maximum values in the bay fluvial valleys where the tsunami wave entered along the river channels. The waves, favored by the confining conditions, entered more than 950 m in the Elqui River mouth and almost 700 m in the Culebrón Stream. Coquimbo Bay comprises a wide and convex littoral zone of approximately 18 km long only interrupted by the mouths of the Elqui River and the Culebrón Stream where small saltmarshes have developed. According to the tide gauge data, the first wave reached the Coquimbo coast only 20 minutes after the earthquake with a maximum height of 0.85 m. 22 minutes later, a second wave arrived with a much higher height (4.3 m) causing the first damages on the littoral and the city. The last wave, the 4th one, occurred 35 minutes after the earthquake and was the highest reaching 4.68 m as well as the most damaging. Despite the existence of works that analyze the characteristics of this event, a more deep and thorough study is still needed of the tsunami geological record in the Coquimbo Bay where a wide variety of forms and deposits were preserved. The making of a geomorphological map has allowed us to differentiate the geological features related with the tsunamigenic event such as sand sheets and debris

  17. Pathways of carbon oxidation in continental margin sediments off central Chile

    DEFF Research Database (Denmark)

    Thamdrup, B; Canfield, Donald Eugene

    1996-01-01

    Rates and oxidative pathways of organic carbon mineralization were determined in sediments at six stations on the shelf and slope off Concepcion Bay at 36.5 degrees S. The depth distribution of C oxidation rates was determined to 10 cm from accumulation of dissolved inorganic C in 1-5-d incubatio...

  18. Pathways of carbon oxidation in continental margin sediments off central Chile

    DEFF Research Database (Denmark)

    Thamdrup, B; Canfield, Donald Eugene

    1996-01-01

    Rates and oxidative pathways of organic carbon mineralization were determined in sediments at six stations on the shelf and slope off Concepcion Bay at 36.5 degrees S. The depth distribution of C oxidation rates was determined to 10 cm from accumulation of dissolved inorganic C in 1-5-d incubatio...

  19. Effect of sediment size on bioleaching of heavy metals from contaminated sediments of Izmir Inner Bay

    Institute of Scientific and Technical Information of China (English)

    Duyusen E.Guven; Gorkem Akinci

    2013-01-01

    The effect of sediment size on metals bioleaching from bay sediments was investigated by using fine (< 45 μm),medium (45-300 μm),and coarse (300-2000μm) size fractions of a sediment sample contaminated with Cr,Cu,Pb,and Zn.Chemical speciation of the metals in bulk and size fractions of sediment were studied before and after bioleaching.Microbial activity was provided with mixed cultures of Acidithiobacillus thiooxidans and Acidithiobacillusferrooxidans.The bioleaching process was carried out in flask experiments for 48 days,by using 5% (W/V) of solid concentration in suspension.Bioleaching was found to be efficient for the removal of selected heavy metals from every size fraction of sediments,where the experiments with the smaller particles resulted in the highest solubilization ratios.At the end of the experimental period,Cr,Cu,Pb and Zn were solubilized to the ratios of 68%,88%,72%,and 91% from the fine sediment,respectively.Higher removal efficiencies can be explained by the larger surface area provided by the smaller particles.The changes in the chemical forms of metals were determined and most of the metal releases were observed from the reducible and organic fractions independent from grain size.Higher concentrations were monitored in the residual fraction after bioleaching period,suggesting they are trapped in this fraction,and cannot be solubilized under natural conditions.

  20. Improving Sediment Transport Prediction by Assimilating Satellite Images in a Tidal Bay Model of Hong Kong

    Directory of Open Access Journals (Sweden)

    Peng Zhang

    2014-03-01

    Full Text Available Numerical models being one of the major tools for sediment dynamic studies in complex coastal waters are now benefitting from remote sensing images that are easily available for model inputs. The present study explored various methods of integrating remote sensing ocean color data into a numerical model to improve sediment transport prediction in a tide-dominated bay in Hong Kong, Deep Bay. Two sea surface sediment datasets delineated from satellite images from the Moderate Resolution Imaging Spectra-radiometer (MODIS were assimilated into a coastal ocean model of the bay for one tidal cycle. It was found that remote sensing sediment information enhanced the sediment transport model ability by validating the model results with in situ measurements. Model results showed that root mean square errors of forecast sediment both at the surface layer and the vertical layers from the model with satellite sediment assimilation are reduced by at least 36% over the model without assimilation.

  1. Anthropogenic mercury signals in lake sediments from southernmost Patagonia, Chile

    Energy Technology Data Exchange (ETDEWEB)

    Hermanns, Yvonne-Marie, E-mail: y-m.hermanns@tu-bs.de; Biester, Harald, E-mail: h.biester@tu-bs.de

    2013-02-15

    Atmospheric mercury fluxes to terrestrial and aquatic surfaces in the Northern Hemisphere have increased since the Industrial Revolution. However fluxes are not well characterized for the Southern Hemisphere, since environmental archives are comparatively scarce. Mercury records from {sup 210}Pb-dated sediment cores of three South Patagonian lakes were investigated in order to reveal the influence of anthropogenic activities on atmospheric mercury deposition in remote lakes of the Southern Hemisphere. Comparison with indicators of organic matter sources (carbon and nitrogen/carbon ratios) and a conservative mineral soil element (zirconium) in the sediments revealed that soil erosion is an important process contributing mercury to these lakes and influenced variation in concentrations through time. However, at ∼ 1900 AD mercury accumulation increased independent from soil erosion and peaked from 1980 to 2000 AD. We attribute this to an increase in atmospheric mercury deposition in this remote region of the Southern Hemisphere. Mean flux ratios, which reflect the increase in modern mercury accumulation compared to pre-1850 AD, lie within a range of 1.4 to 2.4. These values indicate an increase in atmospheric mercury deposition slightly lower than predictions derived from global mercury models that suggest an increase in Hg deposition by a factor of 2 to 3. - Highlights: ► Hg concentrations and accumulation rates were determined in South Patagonian lake sediments. ► Soil erosion was shown to account significantly for short-term variations in Hg accumulation. ► Increased Hg accumulation since 1900 AD (factor of 1.4–2.4) is attributed to a rise in atmospheric Hg. ► Accumulation of anthropogenic Hg peaked between 1980 and 2000 AD (∼ 3 μg m{sup −2} yr{sup −1})

  2. Chronic sublethal effects of San Francisco Bay sediments on nereis (neanthes) arenaceodentata; bioaccumulation from bedded sediments. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Moore, D.; Dillon, T.M.

    1993-09-01

    In previous studies with San Francisco Bay sediments, minimal chronic sublethal effects were detected (Miscellaneous Paper D-93-1 and another Miscellaneous Paper in preparation by Moore and Dillon). To ensure that the lack of effects was not due to a lack of contaminant uptake, a bioaccumulation experiment was conducted. Bioaccumulation from bedded sediments was evaluated following a 9-week exposure with the marine polychaete worm Nereis (Neanthes) arenaceodentata. Two sediments were evaluated, a contaminated San Francisco Bay test sediment and a clean control sediment from Sequim, WA. Animals were exposed as early juveniles through adulthood. Tissues were analyzed for metals, polyaromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and pesticides. Worms exposed to the contaminated San Francisco Bay sediment had significantly higher tissue residues of silver (0.30 mg/kg dry weight) and tributyltin (0.298 mg/kg dry weight). Conversely, tissue residues of control animals were significantly higher in cadmium (0.67 mg/kg dry weight) and lead (1.89 mg/kg dry weight). Small Amounts (0.02 mg/kg dry weight) of aldrin and dieldrin were measured in worms exposed to the contaminated sediment, while dieldrin and 8-BHC were found in Bioaccumulation, Neanthes, Chronic sublethal, San Francisco Bay, Dredged, Material, Sediment.

  3. Heavy metal pollution in intertidal sediments from Quanzhou Bay, China

    Institute of Scientific and Technical Information of China (English)

    YU Ruilian; YUAN Xing; ZHAO Yuanhui; HU Gongren; TU Xianglin

    2008-01-01

    The concentrations of eight heavy metals (Cu,Zn,Pb,Cd,Cr,Ni,Hg,and As) in the intertidal surface sediments from Quanzhou Bay were determined to evaluate their levels and spatial distribution due to urbanization and economic development of Quanzhou region,southeast China.The ranges of the measured concentrations in the sediments are as foilows:24.8-119.7 mg/kg for Cu,105.5-241.9 mg/kg for Zn,34.3-10n9 mg/kg for Pb,0.28-0.89 mg/kg for Cd,51.1-121.7 mg/kg for Cr,16.1-45.7 mg/kg for Ni,0.17-0.74 mg/kg for Hg,and 17.7-30.2 mg/kg for As.The overall average concentrations of above metals exceed the primary standard criteria but meet the secondary standard criteria of the Chinese National Standard of Marine Sediment Quality.Several contents of Cu and Hg exceed the secondary standard criteria at some stations.The results of geoaccumulation index (Igeo) show that Cd causes strong pollution in most of the study area.There are no significant correlations among most of these heavy metals,indicating they have different anthropogenic and natural sources.Some locations present severe pollution by heavy metals depending on the sources,of which sewage outlets,aquatic breeding,and commercial ports are the main sources of contaminants to the area.

  4. New assessment of organic mercury formation in highly polluted sediments in the Lenga estuary, Chile.

    Science.gov (United States)

    Yáñez, Jorge; Guajardo, Marjory; Miranda, Cristian; Soto, César; Mansilla, Héctor D; Flegal, A Russell

    2013-08-15

    Anomalously high levels of mercury in sediment in the Lenga estuary, Chile are comparable to the most contaminated sites previously reported elsewhere. Total mercury (Hgtotal) concentrations range from 0.5 to 129 mg kg(-1) and organic mercury (Hgorg) from 11 to 53 μg kg(-1). The highest levels are in areas near the previous wastewater outfall of a chlo-alkali plant. The results show that the proportion of Hgorg/Hgtotal in the sediment varies by more than two orders of magnitude (0.02-5.7%) according to the concentration of Hgtotal. No correlation between the concentration of Hgorg and Hgtotal was found. The lack of correlation does contrast with the findings of other authors in culture media. Our results indicate that even at very high concentrations of Hgtotal and organic matter do not influence organic mercury formation in estuary sediments. The disparity in Hgtotal and Hgorg concentrations also attests to environmental differences in the formation.

  5. Polychlorinated naphthalenes (PCNs) in riverine and marine sediments of the Laizhou Bay area, North China

    Energy Technology Data Exchange (ETDEWEB)

    Pan Xiaohui [Key Laboratory of Coastal Zone Environmental Processes, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003 (China); Tang Jianhui, E-mail: jhtang@yic.ac.cn [Key Laboratory of Coastal Zone Environmental Processes, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003 (China); Chen Yingjun [Key Laboratory of Coastal Zone Environmental Processes, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003 (China); Li Jun; Zhang Gan [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China)

    2011-12-15

    PCN congeners were analyzed in marine and riverine sediments of the Laizhou Bay area, North China. Concentrations of PCNs ranged from 0.12 to 5.1 ng g{sup -1} dry weight (dw) with a mean value of 1.1 ng g{sup -1} dw. The levels of PCNs varied largely, with industrial group approximately ten folds higher than those of the rural in riverine sediment. A strong impact by direct discharge from local factories was suggested. Similar compositional profiles were found within groups. High resemblance of compositional profiles between industrial samples and Halowax 1014 was observed. It was indicated that PCNs in riverine sediments were mainly from release of industrial usage, with additional contributions from industrial thermal process at certain sites. In marine sediments, it was suggested that PCNs along the coast of Laizhou Bay were mainly controlled by riverine input. While in the central bay, PCN distributions were possibly impacted by combined multiple factors. - Highlights: > We investigated the PCN levels both in the riverine and marine surface sediments of Laizhou Bay. > PCN concentrations in the river sediments of industrial group were ten times higher than in the rural group. > Leakage from industrial materials and thermal processes were the major sources. > PCNs in the coastal sites were more influenced by the river discharge. > In the centre bay, PCN distributions were possibly impacted by combined multiple factors. - A systematic sampling of riverine and marine sediments was conducted in Laizhou Bay area to investigate the distribution and possible sources of PCNs.

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

    Data.gov (United States)

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

  7. 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...

  8. Sediments of Western Mass Bay acquired in 1976 (MEISBURGER76 shapefile)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A seismic reflection survey with concurrent bottom sampling was conducted in western Massachusetts Bay to obtain information on bottom topography and sediments,...

  9. Soft sediment dwelling macro-invertebrates of Rajapur Bay, central west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Harkantra, S.N.; Parulekar, A.H.

    Thirtyfour species of soft sediment dwelling macro-invertebrates were recorded in Rajapur Bay at the proposed effluent discharge location of nuclear power plant. The fauna mainly composed of polychaetes (42.52%), molluscs (39.03%), crustaceans (7...

  10. Sediment Data from the Great Bay Estuarine System acquired in 1986 (NELSON86 shapefile)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The sediment data presented in this data layer were from a geochemical study sited in Great Bay estuarine system of New Hampshire. Textural data were used to support...

  11. Characteristics of Water and Sediment Exchange Between Yangtze Estuary and Hangzhou Bay

    Institute of Scientific and Technical Information of China (English)

    KONG Jun; SONG Zhi-yao; XIA Yun-feng; ZHANG Wei-sheng

    2007-01-01

    Based on the 2-D flow and sediment numerical model of the Yangtze Estuary and the Hangzhou Bay, the characteristics of water and sediment exchange in their joint waters is studied through quantitative calculation and analysis of the characteristics of water flow and sediment transportation. The results show that there is periodical water and sediment exchange in this joint waters, that the net water exchange appears mainly between 0~6 m depth (theoretical datum plane, the same below) offshore and the maximum is near the depth of 2 m, and that the net sediment exchange mainly appears between 0~5 m depth and the maximum is near the depth of 3 m, indicating that the range of water flow passage is different from that of sediment transport from the Yangtze Estuary to the Hangzhou Bay. Combined with the results of numerical simulation, this paper also analyzes the hydrodynamical mechanism influencing water and sediment exchange between the Yangtze Estuary and the Hangzhou Bay, including tidal fluctuation, tidal current kinetic energy, tide-induced residual current and the trace of water particles. Finally, the sediment transportation passage on the Nanhui tidal flat is discussed, and the results show that sediment is transported into the Hangzhou Bay from the south side of Shipilei, while sediment is brought back to the South Channel of the Yangtze Estuary from the north side.

  12. Sediment mineralogy in the Bay of Havana (Cuba): its relation to natural and anthropogenic processes

    Science.gov (United States)

    Fernández-Turiel, J. L.; Chinchón, J. S.; Maldonado, A.

    1996-02-01

    The mineralogical analysis by means of X-ray diffraction of the surficial sediments from the Bay of Havana (Cuba) allows us to identify and quantify the presence of quartz, feldspars, calcite, magnesium calcite, aragonite and dolomite. The distribution of these minerals permits us to distinguish the occurrence of five sedimentary environments (coastal marine, transitional bay-marine, bay, prodelta and Luyanó Drain environments) and related them to the general trends of sedimentary dynamics in the bay. The mineralogy of the coastal marine sediments is dominated by the composition of the local calcareous substratum, i.e., by magnesium calcite and dolomite. These minerals are associated with aragonite in the transitional environment existing between the marine and the bay environments. The sediments in the bay show high contents of aragonite and calcite, while quartz and feldspars are in important quantities in the sediments from the prodelta environments. These mineralogical features are consistent with the natural processes occuring in the Bay of Havana, while the composition of the sediments from the Luyanó Drain environment seem affected by the anthropogenic supply of this drain, showing very high contents of calcitic biogenic products.

  13. Comparison of sediment supply to San Francisco Bay from Coastal and Sierra Nevada watersheds

    Science.gov (United States)

    McKee, L. J.

    2012-12-01

    Quantifying suspended sediment loads is of paramount importance for managing the world's estuaries. To address this information need, a comprehensive analysis was completed for the San Francisco Bay system by combining a number of formerly disparate data sets. Suspended sediment and optical backscatter measurements near the head of the estuary were used to generate a continuous suspended sediment concentration record. In addition, periodic measurements of velocity and suspended sediment variation in the cross-section were used to validate the use of point samples collected on the edge of the channel for generating loads. Suspended sediment loads were determined by combining daily averaged suspended sediment concentrations with daily flow estimates adjusting for dispersive loads. Sediment loads from 482 small drainages around the Bay were determined using 235 station years of suspended sediment data covering 38 watershed locations, regression analysis, and simple modeling. Over 16 years, net annual load to the head of the estuary from its 154000 km2 watershed varied from 0.13-2.58 (mean = 0.89) million metric t, or 5.8 t/km2/yr. Small drainages in the nine-county Bay Area discharged between 0.089 and 4.35 (mean = 1.43) million metric t with an average yield of 175 metric t/km2/yr. Our results indicate that external loads to the Bay are dominated by the many hundreds of urbanized and tectonically active tributaries that drain just 8145 km2 adjacent to the Bay and that during only 5 years did sediment loads from the Central Valley likely exceed loads from the sum of the local smaller drainages. If San Francisco Bay is typical of other estuaries in active tectonic or climatically variable coastal regimes, managers responsible for water quality, sediment accumulating in shipping channels, or restoring wetlands in the world's estuaries may need to more carefully account for proximal small urban drainages that may dominate allochthonous sediment supply.

  14. Variación espacial y temporal de las masas de agua, nutrientes y sedimentación de la materia orgánica e inorgánica en la bahía Mejillones del sur (23° S, Chile Spatial and temporal variability of water masses, nutrients and sedimentation of organic and inorganic matter, in Mejillones del sur bay (23° S, Chile

    Directory of Open Access Journals (Sweden)

    MAURICIO CERDA

    2010-01-01

    temporal variability of physical-chemical properties and sedimentation rates of particulate matter of the water column at a fixed station set within Bahía de Mejillones del Sur, during the austral summer of 2003-2004. The water column was generally characterized by warmer oxygen-rich surface waters, marked stratification gradients between about 10 to 20 m depths and by colder, denser and sub-oxic upwelling waters from 30 m depths to the bottom throughout studied period. The bay was governed by three different water masses: the Surface Sub-Tropical Waters (SSTW, Sub-Antarctic Waters (SAAW and the Equatorial Sub-Surface Waters (ESSW. The surface waters exhibited a clear alternation between weak and short (three to eight days upwelling events and longer (29 days periods of stratification. During the weak upwelling events and at the onset of the stratification periods, sub-oxic to micro-oxic conditions prevailed with elevated nutrient concentrations at the 10 to 15 m depth layer. The variability of oxygen saturation levéis and of the dissolved inorganic nutrients nitrogen (N, phosphorus (P and silicic acid (Si, as well as the behavior of the N:P and Si:NID ratios, indicated the important combined effects of internal recycling of the organic matter in the surface water column and of the contribution of allochthonous nutrients from upwelled bottom waters. The fortnightly variability of the total flux of particulate material collected in sediment traps in the bay suggest that material deposition from the water column is governed by the alternation of upwelling and stratification events. In addition, the sediment traps registered nitrogen impoverishment with increasing depths, suggesting that remineralisation processes affected the settling of particles and the denitrification of the oxydo-reducting deeper waters of the bay.

  15. Sediments of Narragansett Bay acquired in 1960 (MCMASTER60 shapefile)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Gravel, sand, silt, and clay contents were determined for samples from Narragansett Bay and the adjacent Rhode Island Shelf. In the Narragansett Bay system, clayey...

  16. Sediment grab data from October 1999 in Apalachicola Bay, Florida

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Apalachicola Bay National Estuarine Research Reserve and the NOAA Office for Coastal Management worked together to map benthic habitats within Apalachicola Bay,...

  17. The Record of Giant Earthquakes in the Sediments of Lago Villarrica (South-Central Chile)

    Science.gov (United States)

    Moernaut, J.; de Batist, M.; Pino, M.; Brümmer, R.

    2008-05-01

    South-Central Chile is located where the oceanic Nazca plate actively subducts underneath the continental South American plate. This subduction zone has ruptured in great destructive earthquakes with variable magnitude during historical times, with as tragic highlight the 1960 Valdivia earthquake, which accounts for the largest instrumentally recorded earthquake worldwide (Moment Magnitude: 9.5). Damage from severe ground-shaking was reported from up to 1000 km south of the 1960 earthquake epicenter and a devastating tsunami ravaged across the Pacific. The historical earthquake records in South-Central Chile only cover ~500 yrs, so "natural" archives -in which paleo-earthquake activity has been recorded and preserved- need to be explored to reveal a statistically significant earthquake recurrence. In this study, a high-resolution seismic survey on Lago Villarrica has been executed to study its sedimentary infill for fingerprints of severe shaking. The seismic profiles acquired in our study show a succession of voluminous underwater landslide deposits and their related failure scars. Multiple slope failures occurred simultaneously in calm depositional environments, which points toward a strong, instantaneous basin-wide trigger of slope instability. Evaluation of all possible slope failure processes led us to infer that very strong earthquakes are the most likely triggers of these landslide events. Our seismic profiles also show a distinct stratigraphic level of sediment disturbance, locally overlain by a field of sediment volcanoes, which have dimensions up to 70 m wide and 2 m thick. These structures are interpreted as a result of sudden compaction in a buried landslide deposit and subsequent vertical flow of overpressured pore water and entrained sediments which have been expelled at the paleo-lake bottom. We postulate that this process of subsurface sediment mobilization has been triggered by seismic ground-shaking, as such sediment volcanoes have been commonly

  18. Seasonal changes in magnetic parameters of sediments with changing redox conditions in Hiroshima Bay, Japan

    Science.gov (United States)

    Kawamura, Noriko; Amano, Yuka; Ishikawa, Naoto

    2016-07-01

    To describe and interpret the relationship between spatial and seasonal changes in the sedimentary environment of nearshore sediments and their magnetic properties, magnetic and geochemical analyses were performed on sediment samples from three stations in Hiroshima Bay, Japan. Vertical stratification of the water column in the bay changes throughout the year, and magnetic hysteresis parameters and mineralogy in the bay sediments vary in response to changes in redox conditions of bottom waters. Magnetite and hematite are present year-round at all stations. The presence of maghemitized magnetite is inferred at a station located at the entrance to the bay. Greigite is recognized at all stations in September 2011 but is not found at the entrance to the bay when water column stratification is disturbed from October 2011. The presence of maghemite and goethite is inferred at two stations in the inner bay when the sedimentary environment is oxic. The remanent coercivity/coercivity ratio (Hcr/Hc) also varies, both spatially and temporally, which reflects changes in magnetic mineralogy. Increased of Hcr/Hc values are likely to be caused by goethite and/or maghemite formation when water column stratification is disturbed and the seafloor is oxic. Concentration-dependent magnetic parameters do not respond to seasonal changes in the redox conditions of bottom waters. Reaction times and/or changes in chemical and physical conditions may be insufficient to affect these parameters in the sediments of Hiroshima Bay.

  19. Differential arsenic binding in the sediments of two sites in Chile's lower Loa River basin.

    Science.gov (United States)

    Bugueño, Manuel P; Acevedo, Sara E; Bonilla, Carlos A; Pizarro, Gonzalo E; Pasten, Pablo A

    2014-01-01

    Fluvial sediments from two lower Loa River basin sites in northern Chile were compared in order to probe the effects of vegetation and organic matter (OM) on As accumulation in fluvial environments. The two sites were the Sloman dam, which lacks macrophytes and has a low OM content (2.4%) in sediments, and the Quillagua Oasis, which is 23 km downstream from the Sloman site and has a higher OM (6.2%) in sediments and abundant aquatic plant life. The Quillagua site had preferential As enrichment with a co-occurrence pattern that differed from that of the Sloman site, which had a lower As concentration (1528 vs. 262 mg/kg d.w., respectively). At the Quillagua site, As concentration was strongly correlated with Mn and OM (r = 0.91 and 0.85, respectively); while at the Sloman site, As concentration in sediments was significantly correlated with Ca and Sr (r = 0.63 and 0.54, respectively). Sequential extraction analyses showed that the Sloman site had higher percentage of easily exchangeable As within the surface sediment (12%, 45 mg/kg d.w.) compared with the Quillagua site (3%, 40 mg/kg d.w.). These contrasting results suggest that both vegetation and OM control the immobilization and accumulation of As in the arid Loa River basin.

  20. 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.

  1. Distribution Pattern of Heavy Metals in the Surface Sediments of the Jiaozhou Bay

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Grain size analysis and chemical analysis of heavy metals are made for 312 surface samples of the Jiaozhou Bay. Nineteen samples of the waste water taken from the sewage discharge outlets along the eastern coast of the bay are also analyzed for heavy metals. Results show that heavy metals are richer in the east and poorer in the west of the bay. Sedimentary dynamic studies reveal that the distribution of heavy metals in the surface sediments of the Jiaozhou Bay is under the control of hydrodynamics.

  2. Maps showing textural characteristics of benthic sediments in the Corpus Christi Bay estuarine system, south Texas

    Science.gov (United States)

    Shideler, Gerald L.; Stelting, Charles E.; McGowen, Joseph H.

    1981-01-01

    Corpus Christi Bay is a heavily used estuary on the south Texas coast in the northwest Gulf of Mexico (fig. 1).  The Bay is stressed by diverse activities which could substantially affect its ecosystem.  Such activities include shipping, resource production (oil, gas, and construction aggregate), commercial and sport fishing, and recreation.  Shipping activities alone have had a substantial impact on the bay.  For example, the past maintenance of navigation channels has required extensive dredging and spoil disposal within the estuarine system.  Numerous subaqueous spoil disposal sites and subaerial spoil banks are present throughout the bay (fig. 1), and the selection of future spoil disposal sites is becoming a critical local problem.  As activities in the bay increase, the need for effective environmental management becomes increasingly important, and effective management necessitates a good understanding of the bay's physical characteristics.  The objective of this study is to provide detailed information about the textural composition of bottom sediments within the estuarine system, information which could be used in making environmental-management decisions.  Visual descriptions of bottom sediments in Corpus Christi Bay and adjacent areas have been presented by McGowen and Morton (1979).  Additionally, a study of the textures of sediments on the Inner Continental Shelf adjacent to the bay has been presented by Shideler and Berryhill (1977).

  3. Rare earth element fingerprints in Korean coastal bay sediments: Association with provenance discrimination

    Science.gov (United States)

    Kang, Jeongwon; Woo, Han Jun; Jang, Seok; Jeong, Kap-Sik; Jung, Hoi-Soo; Hwang, Ha Gi; Lee, Jun-Ho; Cho, Jin Hyung

    2016-09-01

    Rare earth elements (REEs: La-Lu) in surface sediments collected from the mouth and middle tidal flats of Gomso Bay, South Korea, in August 2011 and May 2012 were analyzed to investigate the fine-grained sediment provenance. The upper continental crust (UCC)-normalized light REEs (LREEs: La to Nd) were more enriched than the middle REEs (MREEs: Sm to Dy) and heavy REEs (HREEs: Ho to Lu), resulting in large (La/Yb)UCC (1.9 ± 0.4) to (Gd/Yb)UCC (1.4 ± 0.2) ratios. The monthly (La/Yb)UCC values differed between the mouth and middle tidal flats due to deposition of fine-grained sediments that originated from distant rivers (the Geum and Yeongsan) and the Jujin Stream, located on the southern shore of the inner bay. We observed relative reductions in the (La/Yb)UCC value and REE content in the sediments from the mouth of the bay compared with those from Jujin Stream sediments. Confined to the middle tidal flat around the KH Line of Jujin Stream, the sediments, most enriched in LREEs but depleted in Eu, were distributed in August as strong Jujin Stream runs. Here, we suggest that an increase in LREE/HREE and decrease in MREE/LREE ratios can be used as a proxy to identify the Jujin Stream provenance in mixed riverine sediments and to trace Jujin Stream sediments within the Gomso Bay tidal flat, especially in the summer rainy season.

  4. Sediment biogeochemistry in an East African mangrove forest (Gazi Bay, Kenya)

    NARCIS (Netherlands)

    Middelburg, J.J.; Nieuwenhuize, J.; Slim, F.J.; Ohowa, B.

    1996-01-01

    The biogeochemistry of mangrove sediments was investigated in several mangrove forest communities in Gazi Bay, a coastal lagoon in Kenya, Africa. Carbon dioxide fluxes, sediment median grain sizes, sedimentary organic carbon, nitrogen and phosphorus contents and pore-water characteristics (ammonium,

  5. Invasion of a rocky intertidal shore by the tunicate Pyura praeputialis in the Bay of Antofagasta, Chile.

    Science.gov (United States)

    Castilla, Juan Carlos; Guiñez, Ricardo; Caro, Andrés U; Ortiz, Verónica

    2004-06-08

    Invasion by marine nonindigenous species (NIS) is a spread phenomenon. The tunicate Pyura praeputialis shows pronounced disjoint geographical distribution: along thousands of kilometers in wave-swept headlands on the southeastern coast of Australia, from where it appears to have originated, and exclusively along 60-70 km inside the Bay of Antofagasta, Chile. mtDNA sequences suggested that the species invaded this rocky shore recently. We used field manipulations and juvenile P. praeputialis transplant techniques to test hypotheses regarding the capacity of the tunicate to survive and grow at different sites and tidal heights inside and outside Antofagasta, and its competitive performance for primary space (inside the Bay) against the native mussel Perumytilus purpuratus. We conclude that survival and growth of P. praeputialis showed no significant differences among sites inside and outside the Bay, and suggest that the restrictive distribution of the species in Chile is caused by a specific oceanographic retention mechanism and/or its brief larval dispersal. We demonstrated that, inside the Bay, P. praeputialis outcompetes Perumytilus from the Mid-Low intertidal, constraining Perumytilus to the Upper Mid-Intertidal, modifying the local pattern of intertidal zonation. We show that predation on P. praeputialis juveniles by starfish and snails constitutes a regulatory mechanism for the setting of its low intertidal limit. Major ecological impacts caused by NIS invasions to rocky shores by aggressive primary space users may result in negative aspects, but also may contribute to biodiversity enhancement. We call attention to the need for increment manipulations and testing of ecological hypotheses regarding marine NIS.

  6. Historical sediment record and distribution of polychlorinated biphenyls (PCBs) in sediments from tidal flats of Haizhou Bay, China.

    Science.gov (United States)

    Zhang, Rui; Zhang, Fan; Zhang, Tiancheng; Yan, Hongqiang; Shao, Wei; Zhou, Li; Tong, Hebing

    2014-12-15

    The spatial and temporal variations and sources of polychlorinated biphenyls (PCBs) in sediment of tidal flat from Haizhou Bay, China were investigated. PCBs concentrations in surface sediments ranged from 1.33 to 6.27ngg(-1) dry weight. Low-chlorinated PCBs, dominated by the tri-PCB homologs, were identified as the prevalent contaminate of surface sediments. These results were in agreement with the fact that tri-PCB homologs are the dominant contaminants in China. In surface sediment, the highest level appeared in the estuary, and it decreased with distance from the Linhong River estuary. PCBs concentrations started to rise from the mid-1950s, and reached a maximum in 2005. PCBs in sediment might originate from surface runoff and discharges of local source as well as slight atmospheric deposition, based on PCA. Additionally, the PCBs levels in the sediments were considered to rarely pose hazard to the aquatic and human health, based on Sediment Quality Guidelines (SQGs).

  7. Interrogation of Chesapeake Bay sediment microbial communities for intrinsic alkane-utilizing potential under anaerobic conditions.

    Science.gov (United States)

    Johnson, Jamie M; Wawrik, Boris; Isom, Catherine; Boling, Wilford B; Callaghan, Amy V

    2015-02-01

    Based on the transient exposure of Chesapeake Bay sediments to hydrocarbons and the metabolic versatility of known anaerobic alkane-degrading microorganisms, it was hypothesized that distinct Bay sediment communities, governed by geochemical gradients, would have intrinsic alkane-utilizing potential under sulfate-reducing and/or methanogenic conditions. Sediment cores were collected along a transect of the Bay. Community DNA was interrogated via pyrosequencing of 16S rRNA genes, PCR of anaerobic hydrocarbon activation genes, and qPCR of 16S rRNA genes and genes involved in sulfate reduction/methanogenesis. Site sediments were used to establish microcosms amended with n-hexadecane under sulfate-reducing and methanogenic conditions. Sequencing of 16S rRNA genes indicated that sediments associated with hypoxic water columns contained significantly greater proportions of Bacteria and Archaea consistent with syntrophic degradation of organic matter and methanogenesis compared to less reduced sediments. Microbial taxa frequently associated with hydrocarbon-degrading communities were found throughout the Bay, and the genetic potential for hydrocarbon metabolism was demonstrated via the detection of benzyl-(bssA) and alkylsuccinate synthase (assA) genes. Although microcosm studies did not indicate sulfidogenic alkane degradation, the data suggested that methanogenic conversion of alkanes was occurring. These findings highlight the potential role that anaerobic microorganisms could play in the bioremediation of hydrocarbons in the Bay.

  8. Sources of mercury to San Francisco Bay surface sediment as revealed by mercury stable isotopes

    Science.gov (United States)

    Gehrke, Gretchen E.; Blum, Joel D.; Marvin-DePasquale, Mark

    2011-01-01

    Mercury (Hg) concentrations and isotopic compositions were examined in shallow-water surface sediment (0–2 cm) from San Francisco (SF) Bay to determine the extent to which historic Hg mining contributes to current Hg contamination in SF Bay, and to assess the use of Hg isotopes to trace sources of contamination in estuaries. Inter-tidal and wetland sediment had total Hg (HgT) concentrations ranging from 161 to 1529 ng/g with no simple gradients of spatial variation. In contrast, inter-tidal and wetland sediment displayed a geographic gradient of δ202Hg values, ranging from -0.30% in the southern-most part of SF Bay (draining the New Almaden Hg District) to -0.99% in the northern-most part of SF Bay near the Sacramento–San Joaquin River Delta. Similar to SF Bay inter-tidal sediment, surface sediment from the Alviso Slough channel draining into South SF Bay had a δ202Hg value of -0.29%, while surface sediment from the Cosumnes River and Sacramento–San Joaquin River Delta draining into north SF Bay had lower average δ202Hg values of -0.90% and -0.75%, respectively. This isotopic trend suggests that Hg-contaminated sediment from the New Almaden Hg District mixes with Hg-contaminated sediment from a low δ202Hg source north of SF Bay. Tailings and thermally decomposed ore (calcine) from the New Idria Hg mine in the California Coast Range had average δ202Hg values of -0.37 and +0.03%, respectively, showing that Hg calcination fractionates Hg isotopes resulting in Hg contamination from Hg(II) mine waste products with higher δ202Hg values than metallic Hg(0) produced from Hg mines. Thus, there is evidence for at least two distinct isotopic signals for Hg contamination in SF Bay: Hg associated with calcine waste materials at Hg mines in the Coast Range, such as New Almaden and New Idria; and Hg(0) produced from these mines and used in placer gold mines and/or in other industrial processes in the Sierra Nevada region and SF Bay area.

  9. Sources of mercury to San Francisco Bay surface sediment as revealed by mercury stable isotopes

    Science.gov (United States)

    Gehrke, Gretchen E.; Blum, Joel D.; Marvin-DiPasquale, Mark

    2011-02-01

    Mercury (Hg) concentrations and isotopic compositions were examined in shallow-water surface sediment (0-2 cm) from San Francisco (SF) Bay to determine the extent to which historic Hg mining contributes to current Hg contamination in SF Bay, and to assess the use of Hg isotopes to trace sources of contamination in estuaries. Inter-tidal and wetland sediment had total Hg (Hg T) concentrations ranging from 161 to 1529 ng/g with no simple gradients of spatial variation. In contrast, inter-tidal and wetland sediment displayed a geographic gradient of δ 202Hg values, ranging from -0.30‰ in the southern-most part of SF Bay (draining the New Almaden Hg District) to -0.99‰ in the northern-most part of SF Bay near the Sacramento-San Joaquin River Delta. Similar to SF Bay inter-tidal sediment, surface sediment from the Alviso Slough channel draining into South SF Bay had a δ 202Hg value of -0.29‰, while surface sediment from the Cosumnes River and Sacramento-San Joaquin River Delta draining into north SF Bay had lower average δ 202Hg values of -0.90‰ and -0.75‰, respectively. This isotopic trend suggests that Hg-contaminated sediment from the New Almaden Hg District mixes with Hg-contaminated sediment from a low δ 202Hg source north of SF Bay. Tailings and thermally decomposed ore (calcine) from the New Idria Hg mine in the California Coast Range had average δ 202Hg values of -0.37 and +0.03‰, respectively, showing that Hg calcination fractionates Hg isotopes resulting in Hg contamination from Hg(II) mine waste products with higher δ 202Hg values than metallic Hg(0) produced from Hg mines. Thus, there is evidence for at least two distinct isotopic signals for Hg contamination in SF Bay: Hg associated with calcine waste materials at Hg mines in the Coast Range, such as New Almaden and New Idria; and Hg(0) produced from these mines and used in placer gold mines and/or in other industrial processes in the Sierra Nevada region and SF Bay area.

  10. Distribution and Ecological Risk Evaluation of Organochlorine Pesticides in Sediments from Xinghua Bay,China

    Institute of Scientific and Technical Information of China (English)

    Wang Yinghui; Qi Shihua; Xing Xinli; Gong Xiangyi; Yang Junhua; Xu Meihui

    2009-01-01

    The concentrations of organochlorine pesticides (OCPs) in sediments from Xinghua (兴化) Bay,Fujian(福建)Province,China,were determined.The OCP concentrations ranged from 2.48 to 313.88 ng/g,with a more serious contamination in the upper sediment But the OCP concentration in the upper layer was less than that in the lower sediment at the exit of the bay due to the influence of the Coriolis force.At the joint of the internal and external bays,OCPs accumulated abundantly because of freshwater and seawater mingling.The isomer percentage combined with isomer ratios Indicated that DDTs (dichlorodiphengltrichloroethanes) were mainly derived from long-term weather soils,while lin dane was introduced recently to the bay.The rivers flowing into the bay contributed more to DDT and HCH (hexachlorocyclohexane) contamination,especially at low tide.Compared with the corresponding quality guidelines from Ingersoll,the sediments from Xinghua Bay were likely to pose biological impairment and should be taken into account

  11. Interferometric Sidescan Bathymetry, Sediment and Foraminiferal Analyses; a New Look at Tomales Bay, California

    Science.gov (United States)

    Anima, Roberto J.; Chin, John L.; Finlayson, David P.; McGann, Mary; Wong, Florence L.

    2008-01-01

    The United States Geological Survey (USGS) in collaboration with Point Reyes National Sea Shore (PRNS), and the Tomales Bay Watershed Council [http://www.tomalesbaywatershed.org/] has completed a detailed bathymetric survey, and sediment and foraminiferal analyses of the floor of Tomales Bay, California. The study goals are to detail the submarine morphology, the sediment distribution, sedimentary features, and distribution of foraminifera to provide a framework for future studies. The USGS collected swath bathymetric data with a SEA SWATHplus interferometric sidescan sonar system (2004, 2005) and an echo sounder system (2006). The data were processed into continuous mosaic images that show bathymetric detail of the bay floor with 0.2-m vertical and 4.0-m horizontal resolution. Acoustic backscatter data from the 2004 and 2005 surveys were processed into 2-m resolution grids. In addition, 27 sediment samples were collected from various parts of the bay for grain size analyses and a comprehensive study of the distribution of foraminifera in Tomales Bay. The foraminiferal analysis determined that the invasive foraminifera Trochammina hadai from Japan was present in Tomales Bay. The project was conducted in response to a request from the National Park Service, and the Tomales Bay Watershed Council who voiced a need to look at the environmental impacts of human input to the surrounding watersheds that ultimately flow into the bay. The mapping, sediment, and foraminiferal data establish a baseline survey for future comparisons of possible geologic and anthropogenic changes that might occur due to changes in land use or development in the surrounding watershed. These data may also aid in determining the possible pathways of pollutants entering the bay from the surrounding watersheds.

  12. Climate signals in Late Holocene sediments from Maxwell Bay and English Strait (South Shetland Islands, Antarctica)

    Science.gov (United States)

    Hass, H. Christian; Schröder, Simon; Kuhn, Gerhard

    2017-04-01

    Climate fluctuations of the past two millennia such as the Little Ice Age and the Medieval Warm Period are reported mainly from the Northern Hemisphere. Evidence from Antarctica is comparably sparse and reveals regional and temporal differences, which are particularly evident at the western and eastern sides of the Antarctic Peninsula. High-resolution coastal-marine sediment cores from the northernmost tip of the West Antarctic Peninsula reveal periods dominated by finer sediments between periods that lack the finer sediment component. In Maxwell Bay this fine sediment (grain size mode around 16 µm) has been traced back to sediment related to the occurrence of glacial meltwater. It was found in sheltered places and meltwater creeks of Potter Cove, a small tributary fjord to Maxwell Bay. In the sediment core this sediment occurs predominantly between 600 and 1250 AD (Medieval Warm Period) whereas it is only sparsely affecting the record between 1450 and 1900 AD (Little Ice Age). The temporal pattern is very similar to global-temperature reconstructions and even resembles temperature reconstructions from the Northern Hemisphere. To avoid local effects that may occur in Maxwell Bay more sediment cores were taken from bays and straits further south of King George Island during Cruise PS97 of RV "Polarstern" in 2016. A core from English Strait reveals completely different sedimentary conditions with no detectable meltwater signal (16 µm). However, the mean grain size record resembles that of the cores from Maxwell Bay. The lack of a clear-cut meltwater sediment class as it occurs further north is likely the result of a much smaller hinterland (Greenwich and Robert islands) when compared to Maxwell Bay between Nelson Island and the much bigger King George Island where glaciers and ice sheets discharge large quantities of very turbid meltwater directly into the bay. It is concluded that during the warmer climate periods a large amount of meltwater was released along the

  13. Environmental geochemistry reflected by rare earth elements in Bohai Bay (North China) core sediments.

    Science.gov (United States)

    Xu, Ya-Yan; Song, Jin-Ming; Duan, Li-Qin; Li, Xue-Gang; Zhang, Ying; Sun, Pei-Yan

    2010-08-05

    In Bohai Bay sediment, two cores were collected to estimate the source of sediments, and assess the environmental changes. Sequential extractions were carried out in this study. Rare earth elements (REE) were leached out from four labile fractions: Exchangeable (L1), Bound to carbonates (L2), Bound to Fe-Mn oxides (L3), Bound to organic matter (L4), and the remainder was Residual (R5). The percentages of REE in different fractions follow the order: R5 > L3 > L2 > L4 > L1. With heavy REE depletion and no pronounced REE fractionation, NASC-normalized REE patterns of Bohai Bay sediments are quite consistent with that of Haihe River sediment, which is the key river of Bohai Bay. Y/Ho ratios of total contents are all much lower than the average value of continental crust, while Y/Ho ratios of L2 are higher than those of other fractions. Based on the patterns of REE and Y/Ho ratios of samples, sediments of Bohai Bay mainly come from terrigenous matters, which are mainly brought by Haihe River. And REE combined with carbonates may be partly inherited from anthropogenic matter. Moreover, environmental changes exert significant influences on the patterns and fractionations of REE, and they can be deduced from the characteristics of REE. Our results on the patterns and burial fluxes of REE reflect two environmental changes: Bohai Bay has been shifting towards more reducing conditions in the last one hundred years, and there was a large flood in 1939.

  14. Intertidal sediments and benthic animals of Roebuck Bay, Western Australia

    NARCIS (Netherlands)

    Pepping, M.; Piersma, T.; Pearson, G.; Lavaleye, M.

    1999-01-01

    Roebuck Bay near Broome (NW Australia) is with itsextensive tidal flats one of the foremost internationallyimportant sites for shorebirds in the Asia-Pacificflyway system. It is home to 150,000 shorebirds (or‘waders’) in the nonbreeding season, which suggeststhat the intertidal flats of the bay have

  15. Tracking riverborne sediment and contaminants in Commencement Bay, Washington, using geochemical signatures

    Science.gov (United States)

    Takesue, Renee K.; Conn, Kathleen E.; Dinicola, Richard S.

    2017-09-29

    Large rivers carry terrestrial sediment, contaminants, and other materials to the coastal zone where they can affect marine biogeochemical cycles and ecosystems. This U.S. Geological Survey study combined river and marine sediment geochemistry and organic contaminant analyses to identify riverborne sediment and associated contaminants at shoreline sites in Commencement Bay, Puget Sound, Washington, that could be used by adult forage fish and other marine organisms. Geochemical signatures distinguished the fine fraction (.063 millimeter, mm) of Puyallup River sediment—which originates from Mount Rainier, a Cascade volcano—from glacial fine sediment in lowland bluffs that supply sediment to beaches. In combination with activities of beryllium-7 (7Be), a short-lived radionuclide, geochemical signatures showed that winter 2013–14 sediment runoff from the Puyallup River was transported to and deposited along the north shore of Commencement Bay, then mixed downward into the sediment column. The three Commencement Bay sites at which organic contaminants were measured in surface sediment did not have measurable 7Be activities in that layer, so their contaminant assemblages were attributed to sources from previous years. Concentrations of organic contaminants (the most common of which were polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and fecal sterols) were higher in the .063-mm fraction compared to the <2-mm fraction, in winter compared to summer, in river suspended sediment compared to river bar and bank sediment, and in marine sediment compared to river sediment. The geochemical property barium/aluminum (Ba/Al) showed that the median percentage of Puyallup River derived fine surface sediment along the shoreline of Commencement Bay was 77 percent. This finding, in combination with higher concentrations of organic contaminants in marine rather than river sediment, indicates that riverborne sediment-bound contaminants are retained in shallow marine

  16. Partitioning behavior of per- and polyfluoroalkyl compounds between pore water and sediment in two sediment cores from Tokyo Bay, Japan.

    Science.gov (United States)

    Ahrens, Lutz; Yamashita, Nobuyoshi; Yeung, Leo W Y; Taniyasu, Sachi; Horii, Yuichi; Lam, Paul K S; Ebinghaus, Ralf

    2009-09-15

    The partitioning behavior of per- and polyfluoroalkyl compounds (PFCs) between pore water and sediment in two sediment cores collected from Tokyo Bay, Japan, was investigated. In addition, the fluxes and temporal trends in one dated sediment core were studied. Short-chain perfluoroalkyl carboxylic acids (PFCAs) (C or = 11) were found only in sediment The perfluoroalkyl sulfonates (PFSAs), n-ethylperfluoro-1-octanesulfonamidoacetic acid (N-EtFOSAA), and perfluorooctane sulfonamide (PFOSA) seemed to bind more strongly to sediment than PFCAs. The enrichment of PFCs on sediment increased with increasing organic matter and decreasing pH. The perfluorocarbon chain length and functional group were identified as the dominating parameters that had an influence on the partitioning behavior of the PFCs in sediment The maximum SigmaPFC contamination in sediment was observed in 2001-2002 to be a flux of 197 pg cm(-2) yr(-1). Statistically significant increased concentrations in Tokyo Bay were found for perfluorooctanesulfonate (PFOS) (1956-2008), perfluorononanoic acid (PFNA) (1990-2008), and perfluoroundecanoic acid (PFUnDA) (1990-2008). Concentrations of PFOSA and N-EtFOSAA increased between 1985 and 2001, but after 2001, the concentration decreased significantly, which corresponded with the phase out of perfluorooctyl sulfonyl fluoride-based compounds by the 3M Company in 2000.

  17. DISTRIBUTION AND COMPOSITION OF PAHs IN SURFACE WATERS,POREWATER AND SEDIMENTS FROM XIAMEN WESTERN BAY

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Xiamen Western Bay's water and sediment quality were studied by determining the levels of sixteen polycyclic aromatic hydrocarbons (PAHs) in water, porewater and sediment samples from nine locations in the bay. Total PAH concentrations varied from 106 to 945 ng/l in water, below detection to 3548 ng/l in porewater, and 247 to 480 ng/g dry weight in surface sediments. PAHs levels in porewater were higher than those in surface water, due to the preference of these hydrophobic compounds for sedimentary phase instead of water. Such a concentration gradient implies a potential flux of pollutants from sediments to overlying water. The PAHs levels in sediments were one to several orders of magnitude lower than those in 1993, suggesting their decreased input in recent years and possible degradation with time.

  18. Sediment accumulation and mercury (Hg) flux in Avicennia marina forest of Deep Bay, China

    Science.gov (United States)

    Li, Ruili; Chai, Minwei; Guo, Meixian; Qiu, Guo Yu

    2016-08-01

    To investigate the rate of sediment accumulation and mercury (Hg) flux in Avicennia marina forest of Deep Bay, China, sediment cores were analyzed. The results showed that Hg concentrations were much higher at all depths compared to the background level. A high correlation between Hg and total organic carbon (TOC) indicated their similar anthropogenic origin. Sedimentation rate was estimated to be 1.38 cm a-1 by 210Pb geochronology. The increase in the mass sediment accumulation rates was rapid (range: 0.5-0.94 g cm-2 a-1), and the Hg fluxes ranged between 76 and 116 ng cm-2 a-1 during the last three decades. The reduction in both Hg concentrations and flux during the last decade may be due to the adoption of contamination control policies. Our results support the notion that the Hg fluxes determined from the sediment cores reveal the effects of anthropogenic influences from the areas around Deep Bay.

  19. Geochronology of anthropogenic radionuclides in Ribeira Bay sediments, Rio de Janeiro, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho Gomes, Franciane de [Programa de Engenharia Nuclear, COPPE/UFRJ, Cidade Universitaria, Caixa Postal 68.509, 21945-970 Rio de Janeiro (Brazil); Godoy, Jose Marcus, E-mail: jmgodoy@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD), Caixa Postal 37750, Barra da Tijuca, 22642-970 Rio de Janeiro (Brazil); Departamento de Quimica, Pontificia Universidade Catolica do Rio de Janeiro (PUC-Rio), Rua Marques de Sao Vicente 225, 22453-900 Rio de Janeiro (Brazil); Godoy, Maria Luiza D.P.; Carvalho, Zenildo Lara de [Instituto de Radioprotecao e Dosimetria (IRD), Caixa Postal 37750, Barra da Tijuca, 22642-970 Rio de Janeiro (Brazil); Tadeu Lopes, Ricardo [Programa de Engenharia Nuclear, COPPE/UFRJ, Cidade Universitaria, Caixa Postal 68.509, 21945-970 Rio de Janeiro (Brazil); Sanchez-Cabeza, Joan-Albert; Osvath, Iolanda [IAEA Marine Environment Laboratories, 4 Quai Antoine Premier, MC98000 Principality of Monaco (Monaco); Drude de Lacerda, Luiz [Laboratorio de Ciencias do Mar, Universidade Federal do Ceara, Fortaleza, Ceara (Brazil)

    2011-09-15

    Ribeira Bay is located approximately 130 km south of the city of Rio de Janeiro and receives discharges of liquid effluent from the Angra dos Reis nuclear power plant (NPP) site, where two pressurized water reactors are located. To test whether the presence of anthropogenic radionuclides in sediments in Ribeira Bay could be correlated to the NPP operations, we sampled seven sediment cores and determined accumulation rates and chronologies. Only one sediment core did not exhibit a superficial mixing layer; this sample was used for dating purposes. Cesium-137 and {sup 207}Bi were observed in this sediment profile, but their presence was associated with atmospheric fall-out rather than the nearby NPP. The exponential decay of {sup 210}Pb concentration with sediment layer depth was verified below a superficial mixing layer for all other sediment cores. Calculated accumulation rates ranged from 1.2 mm y{sup -1} in the inner bay to 6.2 mm y{sup -1} close to its entrance. - Graphical abstract: Display Omitted Highlights: > We have dated seven sediment cores on the region close to the Angra dos Reis nuclear power plant site. > Cs-137 and Bi-207 were detected and were used as a tool to validate the Pb-210 dating results. > The spatial variation of the Pb-210 flux indicates two main sources of sediments: the channel between Ilha Grande (Grande Island), and the continental and soil runoff from the adjacent hills.

  20. Sediment-bound trace metals in Golfe-Juan Bay, northwestern Mediterranean: Distribution, availability and toxicity.

    Science.gov (United States)

    Tiquio, Ma Gregoria Joanne; Hurel, Charlotte; Marmier, Nicolas; Taneez, Mehwish; Andral, Bruno; Jordan, Norbert; Francour, Patrice

    2017-05-15

    The concentration, potential mobility, cation exchange capacity and toxicity of eight sediment-bound metals in Golfe-Juan Bay, France were examined. Results revealed significant spatial gradient of metal contamination along Golfe-Juan coast. The distribution and concentration of the metals appear to be influenced by the geochemical properties of the sediment, proximity to anthropogenic sources and general water circulation in the bay. The portion of trace metals found in the exchangeable, carbonate, oxidizable and reducible fractions of the sediment constitute 31%-58% of the total sediment-bound trace metal content, suggesting significant potential for remobilization of metals into the water column. Pb and Ni content of the sediment exceed the limits of the French marine sediment quality. Whole sediment extracts showed acute toxicity to marine rotifers. This study concludes that monitoring and management of sediment-bound trace metals in Golfe-Juan Bay are important so as not to underestimate their availability and risk to the marine ecosystems. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Matrix-bound phosphine:A new form of phosphorus found in sediment of Jiaozhou Bay

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Matrix-bound phosphine (PH3), a new form of phosphorus, was found in sediment of Jiaozhou Bay in December 2001. Concentration and distribution of PH3 in different layers of sediment with different stations were analyzed. The results show that PH3 concentrations are various with different layers and different stations. PH3 concentrations in the bottom layer of sediment (20-30 cm) are usually higher than those in the surface layer (0-4 cm). The highest PH3 concentration in our investigation reaches 685 ng/kg (dry), which is much higher than those in terrestrial paddy soil, marsh and landfill that have been reported up to now. The correlation analysis indicates that there is no apparent correlation between the concentrations of PH3 and inorganic phosphorus in sediment. However, the correlation between the concentrations of phosphine and organic phosphorus in the bottom layer of sediment is remarkable (R2=0.83). It is considered that PH3 in sediment of Jiaozhou Bay is mainly produced from the decomposition of organic phosphorus in the anaerobic condition, and so PH3 concentrations are related to organic phosphorus concentration and anaerobic environment in sediment. The discovery of PH3 in sediment will give people some new ideas on the mechanisms of phosphorus supplement and biogeochemical cycle in Jiaozhou Bay.

  2. Influence of solar radiation on DOM release from resuspended Florida Bay sediments

    Science.gov (United States)

    Shank, G. C.; Evans, A.; Jaffé, R.; Yamashita, Y.

    2009-12-01

    This study investigated dissolved organic matter (DOM) release from resuspended Florida Bay sediments under dark and sunlit conditions. Much of Florida Bay (located between Everglades and Florida Keys) is very shallow (concentration and composition of DOM in the water column. For our study, sediments were collected at several sites across Florida Bay and ranged from 3-11 percent organic carbon (by weight). Sediments were resuspended in oligotrophic seawater for 48 hours in 1 L quartz flasks in the dark and under simulated solar radiation (SunTest XLS+) at concentrations of 100 mg L-1 and 1 g L-1 (wet weight). Final solutions were analyzed for DOC, chromophoric dissolved organic matter (CDOM), and Excitation Emission Matrix (EEM) fluorescence. Results showed little to no DOC increases in the resuspensions performed under dark conditions, but substantial release of DOM in irradiated resuspensions, especially at high sediment concentrations where DOC increases ranged from 100-500%. The sediments also released substantial quantities of CDOM to solution under irradiated conditions. The magnitude of DOC increases in irradiated resuspensions were well-correlated with the amount of particulate organic carbon (POC) added. Data from EEM-PARAFAC analyses suggests the photochemically produced DOM was comprised of desorbed humic material with a smaller fraction from microbial mediated processes. Our study provides evidence that sediment resuspension episodes in shallow sunlit waters such as Florida Bay have the potential to provide an important source of organic carbon to overlying waters.

  3. Mercury-contaminated sediments in the North Bay: A legacy of the Gold Rush

    Science.gov (United States)

    Jaffe, Bruce E.

    2001-01-01

    A legacy of the Gold Rush is mercury-contaminated sediments in the Bay. Miners used mercury to extract gold from tailings during the gold rush. A large amount of this mercury (some estimates are as great as 10,000 tons) was lost during extraction to the watershed during the gold rush era. This mercury-contaminated hydraulic mining debris made its way to the Bay.

  4. Diurnal variation in rates of calcification and carbonate sediment dissolution in Florida Bay

    Science.gov (United States)

    Yates, K.K.; Halley, R.B.

    2006-01-01

    Water quality and circulation in Florida Bay (a shallow, subtropical estuary in south Florida) are highly dependent upon the development and evolution of carbonate mud banks distributed throughout the Bay. Predicting the effect of natural and anthropogenic perturbations on carbonate sedimentation requires an understanding of annual, seasonal, and daily variations in the biogenic and inorganic processes affecting carbonate sediment precipitation and dissolution. In this study, net calcification rates were measured over diurnal cycles on 27 d during summer and winter from 1999 to 2003 on mud banks and four representative substrate types located within basins between mud banks. Substrate types that were measured in basins include seagrass beds of sparse and intermediate density Thalassia sp., mud bottom, and hard bottom communities. Changes in total alkalinity were used as a proxy for calcification and dissolution. On 22 d (81%), diurnal variation in rates of net calcification was observed. The highest rates of net carbonate sediment production (or lowest rates of net dissolution) generally occurred during daylight hours and ranged from 2.900 to -0.410 g CaCO3 m-2 d-1. The lowest rates of carbonate sediment production (or net sediment dissolution) occurred at night and ranged from 0.210 to -1.900 g CaCO3 m -2 night-1. During typical diurnal cycles, dissolution during the night consumed an average of 29% of sediment produced during the day on banks and 68% of sediment produced during the day in basins. Net sediment dissolution also occurred during daylight, but only when there was total cloud cover, high turbidity, or hypersalinity. Diurnal variation in calcification and dissolution in surface waters and surface sediments of Florida Bay is linked to cycling of carbon dioxide through photosynthesis and respiration. Estimation of long-term sediment accumulation rates from diurnal rates of carbonate sediment production measured in this study indicates an overall average

  5. Polycyclic aromatic hydrocarbons in surface sediments of the Zhelin Bay in the South China Sea

    Institute of Scientific and Technical Information of China (English)

    DONG Qiaoxiang; HUANG Hong; HUANG Changjiang

    2007-01-01

    This study examined the concentrations of polycyclic aromatic hydrocarbons (PAHs) in surface sediments collected in July 2004 from eight stations in the Zhelin Bay, one of the most important bays for large-scale mariculture in Guangdong Province. Thirteen individual parent PAH compounds were identified using high performance liquid chromatography with UV detection. The overall average concentration of total PAHs was 477.0 ng/g, ranging from 146.1 to 928.8 ng/g. Low molecular mass PAHs with two to three rings (e.g., acenaphthene) were dominant in each sample. The PAH concentration varied among sampling stations, with the highest concentration observed at bay outlets and the lowest found at stations outside the bay. Ratios of low to high molecular mass PAHs and fluoranthene to pyrene were used to determine the origin of PAHs, and results indicated mainly petroleum-derived contamination. Compared with other bays and harbors around the world, the total concentrations of PAHs in surface sediments at the Zhelin Bay are moderate, but this does not exclude the possibility of potential impact on human consumers because some strong carcinogenic PAHs with high molecular mass were found at the station with a nearby caged-fish and oyster farm. Long-term monitoring of PAH contamination in the Zhelin Bay is recommended to reduce the potential toxicological effects on aquatic: organisms and humans.

  6. Sediment Deposition, Erosion, and Bathymetric Change in Central San Francisco Bay: 1855-1979

    Science.gov (United States)

    Fregoso, Theresa A.; Foxgrover, Amy C.; Jaffe, Bruce E.

    2008-01-01

    Central San Francisco Bay is the hub of a dynamic estuarine system connecting the San Joaquin and Sacramento River Deltas, Suisun Bay, and San Pablo Bay to the Pacific Ocean and South San Francisco Bay. To understand the role that Central San Francisco Bay plays in sediment transport throughout the system, it is necessary to first determine historical changes in patterns of sediment deposition and erosion from both natural and anthropogenic forces. The first extensive hydrographic survey of Central San Francisco Bay was conducted in 1853 by the National Ocean Service (NOS) (formerly the United States Coast and Geodetic Survey (USCGS)). From 1894 to 1979, four additional surveys, composed of a total of approximately 700,000 bathymetric soundings, were collected within Central San Francisco Bay. Converting these soundings into accurate bathymetric models involved many steps. The soundings were either hand digitized directly from the original USCGS and NOS hydrographic sheets (H-sheets) or obtained digitally from the National Geophysical Data Center's (NGDC) Geophysical Data System (GEODAS) (National Geophysical Data Center, 1996). Soundings were supplemented with contours that were either taken directly from the H-sheets or added in by hand. Shorelines and marsh areas were obtained from topographic sheets. The digitized soundings, depth contours, shorelines, and marsh areas were entered into a geographic information system (GIS) and georeferenced to a common horizontal datum. Using surface modeling software, bathymetric grids with a horizontal resolution of 25 m were developed for each of the five hydrographic surveys. Before analyses of sediment deposition and erosion were conducted, interpolation bias was removed and all of the grids were converted to a common vertical datum. These bathymetric grids were then used to develop bathymetric change maps for subsequent survey periods and to determine long-term changes in deposition and erosion by calculating volumes and

  7. Indicators and impact analysis of sediment from the Changjiang Estuary and East China Sea to the Hangzhou Bay

    Institute of Scientific and Technical Information of China (English)

    WANG Hong; FAN Wei; YUN Caixing

    2004-01-01

    Based on the historical evolution of the Hangzhou Bay, by making use of the conclusions made by the previous research workers and the integration of concrete data, five distinct impact indicators of the sediment from the Changjiang Estuary and the East China Sea to the Hangzhou Bay are summarized. Numerical calculation and analysis indicate that the scouring and deposition of seabed in the Hangzhou Bay are subject to the direct impact of the evolution of the Changjiang Estuary, and the growth and decline and the direction of the sandy bar at Nanhuizui give traces to the sediment transport between the Changjiang Estuary and the Hangzhou Bay. The transport of sediment from the Changjiang Estuary to the Hangzhou Bay occurs mainly in winter and spring seasons and the increase of the Changjiang River runoff and the decrease of sediment charge have caused scouring in the northern coast of the Hangzhou Bay and the seabed erosion along the frontal margin of the Changjiang River Delta.

  8. Evaluations of heavy metal pollution in sediment and Mullus barbatus from the Izmir Bay (Eastern Aegean) during 1997-2009.

    Science.gov (United States)

    Kucuksezgin, Filiz; Kontas, Aynur; Uluturhan, Esin

    2011-07-01

    Izmir Bay is one of the great natural bays of the Mediterranean. The surface sediment and fish samples were collected during 1997-2009. The sediment concentrations of inner bay showed significant enrichments during sampling periods. Outer and middle bays exhibited low levels of metal enrichments except the estuary of Gediz River. The concentrations were generally higher than the background levels from the Mediterranean and Aegean except Cd and Pb levels gradually decreased. Metal EF is used as an index to evaluate anthropogenic influences of metals in sediments. Maximum metal enrichment was found for Hg in the outer bay, while Pb indicated maximum enrichment in the middle-inner bays. Metal levels were evaluated in sediments in accordance with the numerical SQG of the USEPA. The levels of fish tissues were lower than the results reported from polluted areas of the Mediterranean. The highest BAFs were detected for Hg and Cd in fish.

  9. The Levels and Distribution of Polycyclic Aromatic Hydrocarbons (PAH Contamination in Bottom Sediments in Manila Bay

    Directory of Open Access Journals (Sweden)

    Evangeline Santiago

    1997-12-01

    Full Text Available The concentration levels of 18 PAH compounds extracted from 19 bottom sediments from the Limay Coast and 16 bottom sediments from the coast along Metro Manila and Cavitc Province of Manila Bay were determined by Gas Chromatography/Mass Spectrometry.The PAH contamination, the levels of other non-PAH petroleum hydrocarbon compounds. and total organic content in the sediments were assessed in relation to the location and depth of the sampling sites. The PAH concentrations and the levels of other petroleum hydrocarbons in the sediments showed that the spatial distribution of PAH and other hydrocarbon contamination in Manila Bay is largely dependent on the proximity of the sediment deposition site to known point sources of pollution. On the western side, the highest levels of PAH contamination normalized to % TOC (1.29 X 104 at Ll2, 1.28 x 104 at Ll6, 0.55 at Ll3, and 0.54 at Ll5 were obtained from sediments collected at deposition sites near the outfall of the Petron Oil Refinery. On the eastern side. sediments located at the effiuent zones of the Paranaque and Malabon Rivers showed excessively higher levels of PAH normalized to % TOC (3.32 x 104 and 2.87 x 104: respectively compared to those obtained from other sites in the area.The PAH contamination in the sediments from Manila Bay is dominated by alkylated naphthalenes and phenanthrenes which are associated with petrogenic sources. This indicates that the surface sediments in Manila Bay are ex-posed to chronic contamination of petroleum hydrocarbons introduced mainly by direct spillage on the western side and by urban run-off on the eastern side.

  10. POLLUTION ASSESSMENT IN DREDGING SEDIMENT FROM HARBOR AREAS OF THE CIENFUEGOS BAY (CUBA

    Directory of Open Access Journals (Sweden)

    Anabell Pulido Caraballé

    2016-04-01

    Full Text Available The characterization of the dredging sediments is essential for environmental license, control and planning in dredging harbors. Sediment pollution was study in two harbor areas of the Cienfuegos Bay. Dredging sediments from “Camilo Cienfuegos” Refinery port and from area IX of Cienfuegos harbor were characterized. In order to evaluate dredging sediment quality, an analysis of water content, grain size, organic matter and trace metals was done. The results show that the trace elements in the sediments are at natural levels. Due to the absent of Cuban rules for these topics, international criteria for sampling, analysis and sediment quality evaluation were used in the study. Results show that these levels can be considered as typical for harbor areas in which authorization for dredging activities in docks and navigation channel should be granted. The results and methodologies will be applied in others Cuban harbors and navigation channel during the environmental license of dredging sediments.

  11. Reevaluation of Minamata Bay, 25 years after the dredging of mercury-polluted sediments.

    Science.gov (United States)

    Akito, Matsuyama; Shinichiro, Yano; Akihiro, Hisano; Michiaki, Kindaichi; Ikuko, Sonoda; Akihide, Tada; Hirokatsu, Akagi

    2014-12-15

    A detailed investigation of mercury concentrations in the bottom sediments of Minamata Bay was performed in May, 2012. A total of 691 sediment samples were obtained from 107 sampling points in the bay. The weighted average total mercury concentration and the total mass of mercury in the bottom sediments of Minamata Bay were estimated to be 2.3mg/kg dry weight basis and 3.4 tons, respectively. The average concentration of total mercury in the surface layer of the sediments was 3.0mg/kg dry weight basis, and the distribution pattern of total mercury concentrations in the surface layer was found to have changed little in comparison to results reported 25 years ago. In addition, based on the results of seawater monitoring in Minamata Bay from 2010 to 2012, the amounts of total mercury and methylmercury mobilized from sediments and dissolved in the water column were 0.7 and 0.1 kg/yr, respectively.

  12. Trace metal variability in coastal waters of San Jorge Bay, Antofagasta, Chile: An environmental evaluation and statistical approach to propose local background levels.

    Science.gov (United States)

    Valdés, J; Román, D; Guiñez, M; Rivera, L; Ávila, J; Cortés, P; Castillo, A

    2015-11-15

    Between 2008 and 2011, twelve metals from 384 coastal waters samples from San Jorge Bay (Antofagasta, northern Chile) were collected and analyzed. The goal was to evaluate the quality of the bay's water bodies according to the current Chilean Quality Guideline and to establish background levels for these metals. The result suggests that the coastal waters of San Jorge Bay are of very good quality suitable for recreational activities involving human body contact. The natural background thresholds established for this bay were significantly lower than primary and secondary water quality guidelines. The distribution of Cu, Zn and Pb, along the bay's coastline provides evidence of the effects of industrial activity. Both situations suggest that the threshold indicated in the environmental guidelines of the Chilean legislation may be overestimated and do not represent pollution-free environments.

  13. Analysis of sediment, water, and biological samples from the Bay Farm Borrow Area, San Francisco Bay, California

    Energy Technology Data Exchange (ETDEWEB)

    Thom, R.M.; Lefkovitz, L.F. (Battelle/Marine Sciences Lab., Sequim, WA (United States))

    1991-08-01

    The Bay Farm Borrow Area (BFBA) of San Francisco Bay, California, is under consideration as a dredged-material disposal site by the US Army Corps of Engineers (USACE). As part of the analysis of the site, information is required on the quality of benthic biota, sediment, and water in the BFBA. The objective of this report was to provide data on infauna communities, sediment, and water chemistry from samples collected from the BFBA. The samples were collected, and the data will be analyzed by Science Applications International (SAIC). A total of four samples for sediment chemistry, four samples for water chemistry, and 7 samples for infauna communities were analyzed by the Battelle/Marine Sciences Laboratory (MSL). Water analyses included tests for dissolved organic carbon, total suspended solids, four metals, butyltins, polychlorinated biphenyls (PCBs), chlorinated pesticides, polynuclear aromatic hydrocarbons (PAHs), four phenols, and total phenol. Sediment samples were analyzed for percent solids, total organic carbon, total oil and grease, total petroleum hydrocarbons, grain size, 10 metals, butyltins, PCBs, chlorinated pesticides, PAHs, four phenols, and total phenol. The data along with controls and spike recovery analyses, are presented in tables, and the results are discussed in the text. The quality assurance/quality control criteria were met for the analyses as were the detection limits specified by the sponsor.

  14. Hydraulic and sediment characteristics at the North Channel Bridge, Jamaica Bay, New York

    Science.gov (United States)

    Staubitz, W.W.; Wolcott, S.W.

    1985-01-01

    Data were collected during the spring of 1984 in the vicinity of North Channel Bridge in Jamaica Bay, New York to define the hydraulic regime and the physical characteristics and chemical quality of bottom sediments. The data were used in a semiquantitative analysis to predict the effects of bridge replacement and the attendant resuspension of bottom sediments, on the hydraulics and quality of water and bottom sediments. The bay-bottom configuration at the bridge site was defined, and continuous tidal stage and tidal velocity data were collected for about a month. In addition, eight bottom-sediment samples were collected near the bridge and analyzed. Results of the hydraulic analysis show that the proposed bridge should not have any measurable effect on the net water transport at the bridge cross section. The sediment data indicate that bottom sediments are relatively unpolluted in the vicinity of the bridge. Seventy-five percent of the resuspended bottom sediments will probably settle within 186 m of the bridge during an average ebb tide. Metals and nutrients released from the sediments to the water column are expected to be diluted far below detection limits. The extra oxygen demand exerted by the resuspended bottom sediments is also expected to be far less than ambient biochemical oxygen demand of the water column. (USGS)

  15. A seasonal comparison of surface sediment characteristics in Chincoteague Bay, Maryland and Virginia, USA

    Science.gov (United States)

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

    2016-02-03

    Scientists from the U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center conducted a seasonal collection of surficial sediments from Chincoteague Bay and Tom's Cove, between Assateague Island and the Delmarva Peninsula in late March/early April 2014 and October 2014. The sampling efforts were part of a larger U.S. Geological Survey study to assess the effects of storm events on sediment distribution in back-barrier environments of the United States. By sampling during the spring and fall, a more complete understanding of seasonal variability in the area can help determine baseline conditions. The objective of this study was to characterize the sediments of Chincoteague Bay in order to create baseline conditions to incorporate with the hydrodynamic and sediment transport models used to evaluate pre- and post-storm change and compare with future field measurements.

  16. Monsoonal effects on beach and offshore sediments from kalbadevi bay, Ratnagiri, Maharashtra state, India.

    Digital Repository Service at National Institute of Oceanography (India)

    Valsangkar, A.B.; Farnnades, D.

    DAV International Journal of Science Volume-3 Issue-1 2014 ISSN: 2277-5536 (Print); 2277-5641 (Online) 70 MONSOONAL EFFECTS ON BEACH AND OFFSHORE SEDIMENTS... ISSN: 2277-5536 (Print); 2277-5641 (Online) 71 The offshore sediment samples of Kalbadevi Bay were collected in 2006 for the similar purpose. The offshore sampling was carried out along three profiles (OP-01, OP-02 and OP-03) and underwater surface...

  17. Preservación y abundancia de escamas de peces en sedimentos del margen continental de Chile (21-36° S Fish scale preservation and abundance in sediments from the continental margin off Chile (21-36° S

    Directory of Open Access Journals (Sweden)

    JAVIER A DÍAZ-OCHOA

    2008-12-01

    (Mo/Al, S/Al, Fe/Al using eight sediment cores taken from sites under the influence of the oxygen minimum zone off Chile (Iquique: 20°15' S, Mejillones Bay: 23° S, Concepción: 36° S. Off northern Chile (Iquique and Mejillones, fish scales from anchovy (Engraulis ringens and the Myctophidae family are dominant (mean = 90 and 120 scales 1,000 cm-3, respectively, whereas off central-southern Chile (Concepción, jack mackerel (Trachurus murphy scales are the most abundant (mean = 140 scales 1,000 cm-3. The abundance of hake (Merluccius gayi gayi and sardine (Sardinops sagax scales is approximately one order of magnitude lower than that of anchovy or jack mackerel. In general, the highest valúes and widest ranges of variation in the Mo/Al, S/Al, and Fe/Al ratios are found in Mejillones (Mo/Al ~ 0.8-12 mg g-1, S/Al 0.2-4.6 g g-1, Fe/Al 0.3-0.7 g g-1, followed by Iquique (Mo/Al ~ 0.2-1.8, S/Al 0.2-0.7, Fe/Al 0.5-0.8; Concepción has lower, less variable valúes (Mo/Al ~ 0.07, S/Al ~ 0.15, Fe/Al ~ 0.5. According to the Mo/Al ratio, used as an indicator of paleo-oxygenation, reducing conditions in the Mejillones Bay and Iquique sediments are relatively more intense than in those off Concepción. At all three sampling sites, the relationship between the abundance of anchovy scales and the logarithm of the Mo/Al ratio is statistically significant (r² = 0.46, P 1 mg g-1.

  18. The sediment budget of an urban coastal lagoon (Jamaica Bay, NY) determined using 234Th and 210Pb

    Science.gov (United States)

    Renfro, Alisha A.; Cochran, J. Kirk; Hirschberg, David J.; Bokuniewicz, Henry J.; Goodbred, Steven L.

    2016-10-01

    The sediment budget of Jamaica Bay (New York, USA) has been determined using the natural particle-reactive radionuclides 234Th and 210Pb. Inventories of excess thorium-234 (234Thxs, half-life = 24.1 d) were measured in bottom sediments of the Bay during four cruises from September 2004 to July 2006. The mean bay-wide inventory for the four sampling periods ranged from 3.5 to 5.0 dpm cm-2, four to six times that expected from 234Th production in the overlying water column. The presence of dissolved 234Th and a high specific activity of 234Thxs on particles at the bay inlet (∼30 dpm g-1) indicated that both dissolved and particulate 234Th could be imported into the bay from the ocean. Based on these observations, a mass balance of 234Th yields an annual input of ∼39 ± 14 × 1010 g sediment into the bay. Mass accumulation rates determined from profiles of excess 210Pb (half-life = 22.3 y) in sediment cores require annual sediment import of 7.4 ± 4.5 × 1010 g. Both radionuclides indicate that there is considerable marine-derived sediment import to Jamaica Bay, consistent with earlier work using 210Pb. Such sediment input may be important in sustaining longer-term accretion rates of salt marshes in the bay.

  19. Anthropogenic Pb input into Bohai Bay, China: Evidence from stable Pb isotopic compositions in sediments

    Science.gov (United States)

    Hu, Ningjing; Huang, Peng

    2016-04-01

    Anthropogenic Pb input into Bohai Bay, China: Evidence from stable Pb isotopic compositions in sediments Hu Ning-jinga, Huang Pengb,, Liu Ji-huaa, a First Institute of Oceanography, State Oceanic Administration, Qingdao 266061, China b Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China To investigate the source of Pb within Bohai Bay, Pb concentrations and Pb isotopic compositions (204Pb, 206Pb, 207Pb, and 208Pb) of surface sediments in this area were determined. The Pb concentration in this bay varied widely from 6.9 to 39.2 μg/g (average: 21.8 ± 7.8 μg/g), and the Pb isotopic compositions ranged from 0.8338 to 0.8864 (average: 2.0997 ± 0.0180) for 208Pb/206Pb and from 2.0797 to 2.1531 (average: 0.8477 ± 0.0135) for 207Pb/206Pb, presenting in three distinct clusters. The Pb isotopic ratios of sediments from the northeastern (NE zone) and northwestern (NW zone) coastal areas were significantly influenced by anthropogenic sources such as coal combustion and automobile emission. In sediments from the central and southern Bohai Bay (C-S zone); however, Pb mainly originated from the Yellow River catchment, as a result of lithogenic sediment (from rock weathering) accumulation. The Pb isotopic ratios further indicate that, apart from riverine inputs, the neighboring large-scale ports and aerosols significantly contributed to the anthropogenic Pb contained in these sediments. Pb contamination in the Haihe and Luanhe river mouths as well as in the regions near ports is also suggested from anthropogenic enrichment factors. As cities and ports continue to develop around Bohai Bay, a long-term extensive sewage monitoring program is highly recommended.

  20. Estimation of historic flows and sediment loads to San Francisco Bay,1849–2011

    Science.gov (United States)

    Moftakhari, H.R.; Jay, D.A.; Talke, S.A.; Schoellhamer, David H.

    2016-01-01

    River flow and sediment transport in estuaries influence morphological development over decadal and century time scales, but hydrological and sedimentological records are typically too short to adequately characterize long-term trends. In this study, we recover archival records and apply a rating curve approach to develop the first instrumental estimates of daily delta inflow and sediment loads to San Francisco Bay (1849–1929). The total sediment load is constrained using sedimentation/erosion estimated from bathymetric survey data to produce continuous daily sediment transport estimates from 1849 to 1955, the time period prior to sediment load measurements. We estimate that ∼55% (45–75%) of the ∼1500 ± 400 million tons (Mt) of sediment delivered to the estuary between 1849 and 2011 was the result of anthropogenic alteration in the watershed that increased sediment supply. Also, the seasonal timing of sediment flux events has shifted because significant spring-melt floods have decreased, causing estimated springtime transport (April 1st to June 30th) to decrease from ∼25% to ∼15% of the annual total. By contrast, wintertime sediment loads (December 1st to March 31st) have increased from ∼70% to ∼80%. A ∼35% reduction of annual flow since the 19th century along with decreased sediment supply has resulted in a ∼50% reduction in annual sediment delivery. The methods developed in this study can be applied to other systems for which unanalyzed historic data exist.

  1. Geochronology of anthropogenic radionuclides in Ribeira Bay sediments, Rio de Janeiro, Brazil.

    Science.gov (United States)

    de Carvalho Gomes, Franciane; Godoy, José Marcus; Godoy, Maria Luiza D P; de Carvalho, Zenildo Lara; Lopes, Ricardo Tadeu; Sanchez-Cabeza, Joan-Albert; Osvath, Iolanda; de Lacerda, Luiz Drude

    2011-09-01

    Ribeira Bay is located approximately 130 km south of the city of Rio de Janeiro and receives discharges of liquid effluent from the Angra dos Reis nuclear power plant (NPP) site, where two pressurized water reactors are located. To test whether the presence of anthropogenic radionuclides in sediments in Ribeira Bay could be correlated to the NPP operations, we sampled seven sediment cores and determined accumulation rates and chronologies. Only one sediment core did not exhibit a superficial mixing layer; this sample was used for dating purposes. Cesium-137 and (207)Bi were observed in this sediment profile, but their presence was associated with atmospheric fall-out rather than the nearby NPP. The exponential decay of (210)Pb concentration with sediment layer depth was verified below a superficial mixing layer for all other sediment cores. Calculated accumulation rates ranged from 1.2 mm y(-1) in the inner bay to 6.2 mm y(-1) close to its entrance. Copyright © 2011 Elsevier Ltd. All rights reserved.

  2. Distribution and sources of heavy metals in the sediment of Xiangshan Bay

    Institute of Scientific and Technical Information of China (English)

    SUN Weiping; YU Jianjun; XU Xiaoqun; ZHANG Weiyan; LIU Ruijuan; PAN Jianming

    2014-01-01

    Heavy metals in the surface sediments and sediment core from the Xiangshan Bay, a mariculture base on the coast of the East China Sea, were determined by inductively coupled plasma mass spectrometry (ICP-MS) in order to evaluate their levels and sources. The results showed that the levels of Cu, Pb, Zn, and Cr in the sedi-ments of the bay have been generally influenced by anthropogenic inputs since the founding of the People’s Republic of China. In particular, Cu and Zn were polluted to some extent, as evidenced by high enrich-ment factors. Organic matter, grain size, wastewater discharge, and low energy hydrodynamic environment played dominant roles in the heavy metal enrichment in the sediments. The ratio of terrigenous source to marine biogenic deposit of trace metals in the sediments was calculated, revealing that terrigenous inputs were the main source of Cu, Pb, and Zn, while biological pellets contributed much more to the enrichment of Cr and Cd. Considering the influence of biological sources on the enrichment of Cd and Cr, and the fact that the sediment has been polluted by Cu and Zn, the development of mariculture and discharge of waste-water into the Bay should be restricted.

  3. Trapping of fine sediment in a semi-enclosed bay, Palau, Micronesia

    Science.gov (United States)

    Golbuu, Yimnang; Victor, Steven; Wolanski, Eric; Richmond, Robert H.

    2003-08-01

    Airai Bay, Palau, is a small (3 km 2), semi-enclosed, mangrove-fringed, meso-tidal, coral lagoon on the southeast coast of Palau. It drains a small catchment area (26 km 2) of highly erodible soils in an area with high annual rainfall (3.7 m). River floods are short-lived and the sediment load is very large, with suspended fine sediment concentration exceeding 1500 mg l -1. The resulting river plume is about 2 m thick. The brackish water residence time is about 7 days; during this period the plume remains a distinct surface feature even after river runoff has ceased. About 98% of the riverine fine sediment settles in Airai Bay, of which about 15-30% is deposited in the mangroves during river floods. This mud remains trapped in Airai Bay because the bay is protected from ocean swells and the tidal currents and locally generated wind waves are too small to resuspend the mud in quantity. The mud is smothering coral reefs, creating a phase shift from coral to fleshy algae dominance, and is even changing habitats by creating mud banks. The persistence of Airai Bay marine resources may not be possible without improved soil erosion control in the river catchment.

  4. HEAVY METAL CONTENTS IN MARINE SEDIMENTS AND SEAWATER AT TOTOK BAY AREA, NORTH SULAWESI

    Directory of Open Access Journals (Sweden)

    Delyuzar Ilahude

    2017-07-01

    Full Text Available The study area is located in north-eastern part of Tomini Bay, approximately 80 km south of Manado city, North Sulawesi. This area is closed to submarine tailing disposal system in Buyat Bay. Five marine sediment samples and four water samples from seawater and dig wells have been used for heavy metals (Hg, As, CN analyses by using Atomic Absorption Spectrometry (AAS. This study is a part of research conducted by Marine Geological Institute of Indonesia on morphological changes of seabed in the Totok Bay. The result shows that concentration of mercury (Hg in water samples taken from Ratatotok estuary is higher than standards stipulated Government Regulation (Peraturan Pemerintah/PP No. 82/2001. Meanwhile, concentration of arsenic (As is almost reaching its standard threshold, and conversely cyanide (CN concentration is low. This value of mercury (Hg concentration taken from Ratatotok estuary is much higher than water samples from of Buyat Bay estuary. Significant concentration of mercury (Hg analysed from those particular sampling sites indicated high mercury contamination. Therefore, further examination on ground water of dig wells is necessary, especially for mercury analysis (Hg. Furthermore, comparing the formerly obtained data of mercury concentration in the sediment, this particular study concludes that the sediments in the Totok Bay had contaminated by mercury from gold-processing of illegal mining.

  5. Influence of suspended kelp culture on seabed sediment composition in Heini Bay, China

    Science.gov (United States)

    Liu, Yanxia; Huang, Haijun; Yan, Liwen; Liu, Xiao; Zhang, Zehua

    2016-11-01

    Kelp aquaculture activities occupy large nearshore areas with significant effects on sediment properties, primarily caused by the influence of the suspended kelp on local hydrodynamics. Changes in sediment composition and grain-size distributions were investigated prior to and following the commencement of kelp aquaculture activities in Heini Bay in eastern China. Seabed sediment types and the particulate matter in suspension during the kelp seeding and harvesting periods, and in sediment cores, were analyzed. While suspended sediment in the kelp aquaculture area was up to 20% organic material, sediment organic content on the seabed remained at similar levels as areas lacking aquaculture. The composition of the seabed sediment in the kelp aquaculture area became finer-grained by the capture of fine particles. Within the kelp aquaculture area, the sediments are poorly sorted and positively skewed, whereas at the shoreward and seaward of the aquaculture area the sediments are relatively coarse-grained, well-sorted and nearly symmetrically distributed. Therefore, the kelp aquaculture activities not only increase the fine particulate fraction in the sediments within the aquaculture area, but also result in similar deposits seaward of it, indicating that seabed erosion and accretion is also controlled by the sediment source and the hydrodynamic conditions. The analysis of sediment cores showed that kelp culturing refines the sediment by preferentially capturing particles in the 38-40 μm size class, while having no effect on the <32 μm fractions, as evidenced by the positive skew of the surficial sediments. The captured particle size class became well mixed into the sediment, thereby changing the composition of the sediment in the uppermost layer of the core, indicating the existence of continuous and stable hydrodynamic conditions within the kelp aquaculture area. The same effect was observed in the seabed sediments seaward of the aquaculture area.

  6. Radioisotopic data of sediment collected in Mobile and Bon Secour Bays, Alabama

    Science.gov (United States)

    Marot, Marci E.; Smith, Christopher G.

    2012-01-01

    The focus of this study was to determine the extent of natural and (or) anthropogenic impacts on the sedimentary records of Mobile and Bon Secour Bays, Alabama during the last 150 years. These bays are unique in that anthropogenic activities are generally widespread and span both the eastern and western shorelines. However, there is a clear distinction in the types of human development and infrastructure between the western and eastern shorelines. These activities and the differences in land-use and -change influence the overall supply and remobilization of sediment to and within the bay. These factors could subsequently threaten the health and integrity of these environments and their ability to mitigate against long-term processes associated with climate change. In an attempt to characterize long-term accretion rates within the Mobile Bay Estuarine System (MBES), seven box cores were collected and analyzed for excess lead-210 (210Pbxs, the difference between total and supported 210Pb) and cesium-137 (137Cs) activities. The MBES receives sediment and water from the Alabama and Tombigbee River watersheds, which converge into the Mobile-Tensaw River (MTR) system just prior to discharging into Mobile Bay. Riverine discharge from the MTR system to the bay is second only to the Mississippi River discharge to the Gulf of Mexico for the conterminous United States.

  7. Hydrodynamic and Sediment Transport Processes in Long Bay of the Carolinas

    Science.gov (United States)

    Ma, Y.; Xu, K.; He, R.; Wren, P. A.; Gong, Y.; Quigley, B.; Tarpley, D.

    2010-12-01

    The coastline along Long Bay of the Carolinas is a fast-growing and heavily-developed area supporting local populations, infrastructure, and a large tourism industry. Myrtle Beach and its adjacent sandy beaches are popular tourist destinations that attract millions of visitors each year, representing one of the state’s most essential natural resources. The economy of this region is closely related to the stability of the sandy beaches, which are vulnerable to coastal erosion during severe storm events. Quantifying the sediment transport processes in the nearshore and inner continental shelf regions is thus critical for both understanding the regional sediment budget and implementing effective coastal management. As a first step toward investigating the sediment transport processes, a three-dimensional coupled hydrodynamic-sediment transport model for Long Bay in the Carolinas has been developed. The model, based on the Regional Ocean Modeling System (ROMS), spans from Cape Fear estuary in NC to Winyah Bay estuary in SC. It considers the delivery of fluvial sediment from the Cape Fear and Pee Dee Rivers, resuspension from seabed, and transport of suspended sediment by ambient currents and waves calculated using Simulating WAve Nearshore model (SWAN). Our model simulations are driven by observed wind fields, which were collected at nearby meteorological stations maintained by National Data Buoy Center as well as at six buoys by the Palmetto Wind Research Project at Coastal Carolina University. Spatially varying sea bed conditions consisting of both hard bottoms and sandy bodies are applied in the calculation. The model is one-way nested inside a large-scale coastal circulation model that covers both the Middle Atlantic Bight and the South Atlantic Bight and provides dynamically consistent and numerically accurate circulation open boundary conditions. Modeling results indicate both wind-driven currents and storm-induced waves are capable of resuspending sandy

  8. Shift in detrital sedimentation in the eastern Bay of Bengal during the late Quaternary

    Indian Academy of Sciences (India)

    C Prakash Babu; J N Pattan; K Dutta; N Basavaiah; G V Ravi Prasad; D K Ray; P Govil

    2010-06-01

    Down-core variations of granulometric, geochemical and mineral magnetism of a 70-cm long sediment core retrieved from the eastern Bay of Bengal abyssal region were studied to understand sedimentation pattern and sediment provenance during the last ∼12 kyr BP. Based on down-core physical and elemental variations, three units were identified: unit 3 (70–43 cm) is a ∼30 cm thick clayey silt organic carbon-rich (0.5–0.92%) turbidite probably delivered by the Brahmaputra River during the late Quaternary period. Units 2 (43–24 cm) and 1 (24–0 cm) represent enhanced and reduced supply of coarse-grained detrital sediments from the Ganges River during early and late Holocene period, respectively. Increased terrigenous supply dilutes calcium carbonate (CaCO3) and biogenic elements (P, Ba and Cu) in units 3 and 2. On the contrary, a reduction in detrital input enhances CaCO3 and biogenic elements in unit 1. Lithogenic elements (Ti, Al, K and Rb) and shale-normalized REE patterns in all three units suggest terrigenous source. The shift in provenance from the Brahmaputra to the Ganges derived sediments is evident by a sharp increase in sediment grain size, increased concentration and grain size assemblages of magnetic minerals, lithogenic elements concentration and Lan/Ybn ratio. This study highlights terrigenous dilution on biogenic sedimentation in the eastern Bay of Bengal sediments.

  9. Palaeoclimatic significance of gypsum pseudomorphs in the inner shelf sediments off Machalipatnam bay

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, V.P.

    Pseudo-gypsum crystals have been found in the coarse fraction of the sediments from the inner continental shelf off Machilipatnam Bay. They range in size from 3 to 7 mm are elongate and lenticular in shape. Bassanite and calcite are pseudomorphs...

  10. Watershed Implications of Sediment and Nutrient Pollution in the Guánica Bay Watershed

    Science.gov (United States)

    The U.S. Coral Reef Task Force (USCRTF), a collaboration of federal, commonwealth, and non-government agencies, recently initiated a program to limit sediment runoff to the coral reefs outside Guánica Bay, Puerto Rico. Municipal and agricultural growth in the Guánic...

  11. Particle fluxes in the Bay of Bengal measurEd. by sediment traps

    Digital Repository Service at National Institute of Oceanography (India)

    Ramaswamy, V.; Parthiban, G.

    Particle fluxes were measured between October, 1987 and March, 1988 using six automated time series sediment traps at three locations in the northern, central and southern Bay of Bengal. Particle fluxes varied between 16.8 and 345 mg m/2 day/1...

  12. Oil characterization and distribution in shoreline sediments of Pensacola Bay, Florida following the Deepwater Horizon spill

    Science.gov (United States)

    Barrier islands of Northwest Florida were heavily oiled during the Deepwater Horizon spill, but less is known about the impacts to the shorelines of the associated estuaries. Shoreline sediment oiling was investigated at 18 sites within the Pensacola Bay, Florida system prior to...

  13. Pliocene mass failure deposits mistaken as submarine tsunami backwash sediments - An example from Hornitos, northern Chile

    Science.gov (United States)

    Spiske, Michaela; Bahlburg, Heinrich; Weiss, Robert

    2014-05-01

    In this study we question the former interpretation of a shallow marine backwash tsunami origin of a conspicuous Pliocene coarse clastic unit at Hornitos, northern Chile, and instead argue for a debris flow origin for this unit. We exclude a relation to a tsunami in general and to the Eltanin impact in particular. The observed deposit at Hornitos was not generated either directly (impact-triggered tsunami) or indirectly (submarine mass flow caused by seismic shaking) by an impact. Re-calculation of the alleged impact tsunami including consideration of the Van Dorn effect shows that an impact in the Southern Ocean did not cause a significant tsunami at Hornitos. Impact-related seismic shaking was not able to trigger slides several thousands of kilometers away because the Eltanin event was a deep sea-impact that did not create a crater. Additionally, the biostratigraphic age of 5.1-2.8 Ma of the associated La Portada Formation is not concurrent with the newly established age of 2.511 ± 0.07 Ma for the Eltanin impact. Instead, we argue for an origin of the conspicuous unit at Hornitos as a debris flow deposit caused by an earthquake in the Andean subduction zone in northern Chile. Our re-interpretation considers the local synsedimentary tectonic background, a comparison to recent submarine tsunami sediments, and recent examples of mass wasting deposits along the Chilean margin. The increased uplift during the Pliocene caused oversteepening of the coastal scarp and entailed a contemporaneous higher frequency of seismic events that triggered slope failures and cliff collapses. The coarse clastic unit at Hornitos represents an extraordinary, potentially tsunami-generating mass wasting event that is intercalated with mass wasting deposits on a smaller scale.

  14. Effects of ghost shrimp on zinc and cadmium in sediments from Tampa Bay, FL

    Science.gov (United States)

    Klerks, P.L.; Felder, D.L.; Strasser, K.; Swarzenski, P.W.

    2007-01-01

    This study investigated the effects that ghost shrimp have on the distribution of metals in sediment. We measured levels of HNO3-extractable zinc and cadmium in surface sediment, in ghost shrimp burrow walls and in sediment ejected by the ghost shrimp from their burrows, at five sandy intertidal sites in Tampa Bay. Ghost shrimp densities and their rate of sediment ejection were also quantified, as were sediment organic content and silt + clay content. Densities of ghost shrimp (Sergio trilobata and Lepidophthalmus louisianensis) averaged 33/m2 at our sites, and they ejected sediment at an average rate of 28 g/burrow/day. Levels of both Zn and Cd were significantly higher in burrow walls than in surface sediments. Sediment ejected by the shrimp from their burrows had elevated levels of Zn (relative to surface sediments) at one of the sites. Sediment organic content and silt + clay content were higher in burrow-wall sediments than in ejected sediment, which in turn tended to have values above those of surface sediments. Differences in levels of HNO3-extractable Zn and Cd among sediment types may be a consequence of these sediments differing in other physiochemical characteristics, though the differences in metal levels remained statistically significant for some sites after correcting for differences in organic content and silt + clay content. We conclude that the presence of ghost shrimp burrows contributes to spatial heterogeneity of sedimentary metal levels, while the ghost shrimp bioturbation results in a significant flux of metals to the sediment surface and is expected to decrease heterogeneity of metal levels in sedimentary depth profiles.

  15. AMS measurement of {sup 10}Be concentrations in marine sediments from Chile Trench at the TANDAR laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, D., E-mail: darodrig@tandar.cnea.gov.ar [Departamento de Física Experimental, Laboratorio TANDAR, GIyA, Comisión Nacional de Energía Atómica, Av. Gral. Paz 1499, B1650KNA San Martín (Argentina); CONICET, Av. Rivadavia 1917, C1033AAJ Buenos Aires (Argentina); Arazi, A. [Departamento de Física Experimental, Laboratorio TANDAR, GIyA, Comisión Nacional de Energía Atómica, Av. Gral. Paz 1499, B1650KNA San Martín (Argentina); CONICET, Av. Rivadavia 1917, C1033AAJ Buenos Aires (Argentina); Fernández Niello, J.O. [Departamento de Física Experimental, Laboratorio TANDAR, GIyA, Comisión Nacional de Energía Atómica, Av. Gral. Paz 1499, B1650KNA San Martín (Argentina); CONICET, Av. Rivadavia 1917, C1033AAJ Buenos Aires (Argentina); Instituto de Investigación e Ingeniería Ambiental, Universidad Nacional de San Martín, 25 de Mayo y Francia, B1650BWA San Martín, Buenos Aires (Argentina); Martí, G.V. [Departamento de Física Experimental, Laboratorio TANDAR, GIyA, Comisión Nacional de Energía Atómica, Av. Gral. Paz 1499, B1650KNA San Martín (Argentina); and others

    2017-03-15

    The {sup 10}Be/{sup 9}Be ratios in marine sediments samples from the Southern Chile Trench have been measured using accelerator mass spectrometry (AMS). The samples were measured at the TANDAR accelerator, where the discrimination of the {sup 10}Be radionuclides was achieved by means of a passive absorber in front of an ionization chamber. This setup along with the high voltage available, provided a complete suppression of the {sup 10}B isobar interference. The obtained values for the {sup 10}Be concentrations, of the order of 10{sup 9} atoms/g, are the first {sup 10}Be measurements from the Southern Chile Trench and offer an excellent tracer to quantitatively study the recycling of sediments in Andean magmas.

  16. Polychlorinated biphenyl source attribution in Green Bay, Wisconsin, USA, using multivariate similarity among congener profiles in sediment samples.

    Science.gov (United States)

    Cacela, Dave; Beltman, Douglas J; Lipton, Joshua

    2002-08-01

    Polychlorinated biphenyl (PCB) congener concentrations measured in 1,189 sediment samples from Green Bay (MI/WI, USA), Lake Michigan (MI/WI, USA), and the Fox River (WI, USA) were analyzed statistically to evaluate whether PCB congener profiles in outer Green Bay are more similar to those observed in inner Green Bay or Lake Michigan. Similarities among PCB profiles were assessed with complementary multivariate analysis techniques: Principal component analysis (PCA), cluster analysis, and classification trees. The PCA indicated that profiles in outer Green Bay are distinct from those of inner Green Bay or Lake Michigan but are more similar to those of inner Green Bay. The outer bay profiles are dissimilar to profiles that would result from a simple process of mixing contaminated sediments from the inner bay with Lake Michigan sediments and, therefore, support the conclusion that contaminants in outer Green Bay come from discharges of the Fox River. Several classification trees based on small sets of congener proportions defined simple rules that consistently distinguished the regional profiles. Application of these rules to classify the outer bay samples suggests that the profiles of less than 7% of outer bay samples are similar to Lake Michigan profiles. These results are interpreted with respect to physical transport and chemical weathering processes that may account for the observed differences.

  17. Bottom Sediments -- Cape Ann to Casco Bay (FOLGER75 shapefile)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The reconnaissance maps upon which this data set is based show the areal distribution of the major bottom sediment types covering the sea floor off eastern New...

  18. Biogeochemical characteristics of sedimenting particles in Dona Paula Bay, India

    Digital Repository Service at National Institute of Oceanography (India)

    DeSouza, F.P.; Garg, A.; Bhosle, N.B.

    of total sedimented particulate matter (TPM), biogenic silica (BSi) and total neutral carbohydrates (TCHO). TPM, BSi and TCHO fluxes showed seasonal and annual variations. Fluxes of BSi showed significant correlations with the fluxes of TCHO and fucose...

  19. Polycyclic aromatic hydrocarbon pollution in the surface water and sediments of Chabahar Bay, Oman Sea.

    Science.gov (United States)

    Agah, Homira; Mehdinia, Ali; Bastami, Kazem Darvish; Rahmanpour, Shirin

    2017-02-15

    In the present study, the concentrations and distribution of 16 polycyclic aromatic hydrocarbons (PAHs) in the water and surface sediments from the Chabahar Bay, Oman Sea, were investigated in May (premonsoon) and December (postmonsoon) 2012. The concentrations of PAHs in the surface water samples ranged from 1.7 to 2.8ngl(-1) and from 0.04 to 59.6ngl(-1) in pre- and postmonsoon, respectively. In general, the PAH levels of the water samples from Chabahar Bay were higher in postmonsoon than in premonsoon (p<0.05). The concentrations of PAHs in the sediment samples varied from undetectable levels to 92.8ngg(-1) d.w. in both seasons. The seasonal comparison of the results in sediment samples showed that the overall concentration of PAH compounds was higher in the postmonsoon season (p<0.05).

  20. Estimation of suspended sediment flux from acoustic Doppler current profiling along the Jinhae Bay entrance

    Institute of Scientific and Technical Information of China (English)

    WANG Yaping; CHU Yong Shik; LEE Hee Jun; HAN Choong Keun; OH Byung Chul

    2005-01-01

    A Nortek acoustic Doppler current profiler (NDP) was installed on a moving vessel to survey the entrance to the Jinhae Bay on August 22~23, 2001. The current velocity and acoustic backscattering signal were collected along two cross-sections; water samples were also collected during the measurement. The acoustic signals were normalized to compensate for the loss incurred by acoustic beam spreading in the seawater. The in situ calibration shows that a significant relationship is present between suspended sediment concentrations (SSC) and normalized acoustic signals. Two acoustic parameters have been determined to construct an acoustic-concentration model.Using this derived model, the SSC patterns along the surveyed cross-sections were obtained by the conversion of acoustic data. Using the current velocity and SSC data, the flux of suspended sediment was estimated. It indicates that the sediment transport into the bay through the entrance has an order of magnitude of 100 t per tidal cycle.

  1. Seasonal changes of magnetic minerals and their grain sizes in the Hiroshima Bay sediments

    Science.gov (United States)

    Kawamura, N.; Ishikawa, N.

    2011-12-01

    Frequent outbreaks of red tide have been reported since 1970 in the Hiroshima bay, and the red tide is caused by a bloom of dinoflagellates. Iron is an essential element for dinoflagellates, and is supplied as bivalent or trivalent ions and iron compounds from lands to sea. For damage predictions of red tide, it is important to research the distribution of iron in the bay. The acidification of seawater during summer has been also observed in the Hiroshima Bay. Increase of CO2 concentration and decrease of dissolved oxygen (DO) content in seawater cause an anoxic condition in the bay. It is known that iron oxides are dissolved and sulfides are formed in an anoxic condition. For clarifying variations of the distribution and mode of iron in sediments and bottom water in the Hiroshima Bay, we investigated kinds of iron compounds in the sediments and the amount of dissolved iron in the bottom waters. Sediment cores of 5cm in depth were taken at three sites in the Hiroshima Bay by using a multiple corer and crab sampler. Data of oceanographic observations at these sites showed that the temperature of the bottom water increased, whereas DO and pH values decreased during the sampling period. The sediment samples were composed of clayey silt. We measured dissolved iron concentration in interstitial and bottom waters filtered above 0.45 um grains, and performed magnetic hysteresis measurements and high temperature magnetometry on the sediment samples. The presence of magnetite (Fe3O4) and hematite (Fe2O3) were recognized in all analyzed samples, whereas greigite (Fe3S4) appeared at these sites with an anoxic condition in the bottom water. Magnetic grain size increased from June to August, while iron concentration increased in the bottom waters. It is suggested that magnetite and hematite were dissolved and greigite was formed, associated with the proceeding of the anoxic condition, and that the grain-size of magnetic minerals and the iron concentration of the bottom water

  2. Sediment geochemistry of Corte Madera Marsh, San Francisco Bay, California: have local inputs changed, 1830-2010?

    Science.gov (United States)

    Takesue, Renee K.; Jaffe, Bruce E.

    2013-01-01

    Large perturbations since the mid-1800s to the supply and source of sediment entering San Francisco Bay have disturbed natural processes for more than 150 years. Only recently have sediment inputs through the Sacramento-San Joaquin Delta (the Delta) decreased to what might be considered pre-disturbance levels. Declining sediment inputs to San Francisco Bay raise concern about continued tidal marsh accretion, particularly if sea level rise accelerates in the future. The aim of this study is to explore whether the relative amount of local-watershed sediment accumulating in a tidal marsh has changed as sediment supply from the Sacramento-San Joaquin Rivers has decreased. To address this question, sediment geochemical indicators, or signatures, in the fine fraction (silt and clay) of Sacramento River, San Joaquin River, San Francisco Bay, and Corte Madera Creek sediment were identified and applied in sediment recovered from Corte Madera Marsh, one of the few remaining natural marshes in San Francisco Bay. Total major, minor, trace, and rare earth element (REE) contents of fine sediment were determined by inductively coupled plasma mass and atomic emission spectroscopy. Fine sediment from potential source areas had the following geochemical signatures: Sacramento River sediment downstream of the confluence of the American River was characterized by enrichments in chromium, zirconium, and heavy REE; San Joaquin River sediment at Vernalis and Lathrop was characterized by enrichments in thorium and total REE content; Corte Madera Creek sediment had elevated nickel contents; and the composition of San Francisco Bay mud proximal to Corte Madera Marsh was intermediate between these sources. Most sediment geochemical signatures were relatively invariant for more than 150 years, suggesting that the composition of fine sediment in Corte Madera Marsh is not very sensitive to changes in the magnitude, timing, or source of sediment entering San Francisco Bay through the Delta. Nor

  3. Observations of pockmark flow structure in Belfast Bay, Maine, Part 3: implications for sediment transport

    Science.gov (United States)

    Fandel, Christina L.; Lippmann, Thomas C.; Foster, Diane L.; Brothers, Laura L.

    2017-01-01

    Current observations and sediment characteristics acquired within and along the rim of two pockmarks in Belfast Bay, Maine, were used to characterize periods of sediment transport and to investigate conditions favorable to the settling of suspended sediment. Hourly averaged Shields parameters determined from horizontal current velocity profiles within the center of each pockmark never exceed the critical value (approximated with the theoretical model of Dade et al. 1992). However, Shields parameters estimated at the pockmark rims periodically exceed the critical value, consistent with conditions that support the onset of sediment transport and suspension. Below the rim in the near-center of each pockmark, depth-averaged vertical velocities were less than zero (downward) 60% and 55% of the time in the northern and southern pockmarks, and were often comparable to depth-averaged horizontal velocities. Along the rim, depth-averaged vertical velocities over the lower 8 m of the water column were primarily downward but much less than depth-averaged horizontal velocities indicating that suspended sediment may be moved to distant locations. Maximum grain sizes capable of remaining in suspension under terminal settling flow conditions (ranging 10–170 μm) were typically much greater than the observed median grain diameter (about 7 μm) at the bed. During upwelling flow within the pockmarks, and in the absence of flocculation, suspended sediment would not settle. The greater frequency of predicted periods of sediment transport along the rim of the southern pockmark is consistent with pockmark morphology in Belfast Bay, which transitions from more spherical to more elongated toward the south, suggesting near-bed sediment transport may contribute to post-formation pockmark evolution during typical conditions in Belfast Bay.

  4. Observations of pockmark flow structure in Belfast Bay, Maine, Part 3: implications for sediment transport

    Science.gov (United States)

    Fandel, Christina L.; Lippmann, Thomas C.; Foster, Diane L.; Brothers, Laura L.

    2017-02-01

    Current observations and sediment characteristics acquired within and along the rim of two pockmarks in Belfast Bay, Maine, were used to characterize periods of sediment transport and to investigate conditions favorable to the settling of suspended sediment. Hourly averaged Shields parameters determined from horizontal current velocity profiles within the center of each pockmark never exceed the critical value (approximated with the theoretical model of Dade et al. 1992). However, Shields parameters estimated at the pockmark rims periodically exceed the critical value, consistent with conditions that support the onset of sediment transport and suspension. Below the rim in the near-center of each pockmark, depth-averaged vertical velocities were less than zero (downward) 60% and 55% of the time in the northern and southern pockmarks, and were often comparable to depth-averaged horizontal velocities. Along the rim, depth-averaged vertical velocities over the lower 8 m of the water column were primarily downward but much less than depth-averaged horizontal velocities indicating that suspended sediment may be moved to distant locations. Maximum grain sizes capable of remaining in suspension under terminal settling flow conditions (ranging 10-170 μm) were typically much greater than the observed median grain diameter (about 7 μm) at the bed. During upwelling flow within the pockmarks, and in the absence of flocculation, suspended sediment would not settle. The greater frequency of predicted periods of sediment transport along the rim of the southern pockmark is consistent with pockmark morphology in Belfast Bay, which transitions from more spherical to more elongated toward the south, suggesting near-bed sediment transport may contribute to post-formation pockmark evolution during typical conditions in Belfast Bay.

  5. Sediment transport in the San Francisco Bay Coastal System: an overview

    Science.gov (United States)

    Barnard, Patrick L.; Schoellhamer, David H.; Jaffe, Bruce E.; McKee, Lester J.; Barnard, P.L.; Jaffee, B.E.; Schoellhamer, D.H.

    2013-01-01

    The papers in this special issue feature state-of-the-art approaches to understanding the physical processes related to sediment transport and geomorphology of complex coastal–estuarine systems. Here we focus on the San Francisco Bay Coastal System, extending from the lower San Joaquin–Sacramento Delta, through the Bay, and along the adjacent outer Pacific Coast. San Francisco Bay is an urbanized estuary that is impacted by numerous anthropogenic activities common to many large estuaries, including a mining legacy, channel dredging, aggregate mining, reservoirs, freshwater diversion, watershed modifications, urban run-off, ship traffic, exotic species introductions, land reclamation, and wetland restoration. The Golden Gate strait is the sole inlet connecting the Bay to the Pacific Ocean, and serves as the conduit for a tidal flow of ~ 8 × 109 m3/day, in addition to the transport of mud, sand, biogenic material, nutrients, and pollutants. Despite this physical, biological and chemical connection, resource management and prior research have often treated the Delta, Bay and adjacent ocean as separate entities, compartmentalized by artificial geographic or political boundaries. The body of work herein presents a comprehensive analysis of system-wide behavior, extending a rich heritage of sediment transport research that dates back to the groundbreaking hydraulic mining-impact research of G.K. Gilbert in the early 20th century.

  6. Mercury pollution in sediments, benthic organisms and inshore fishes of Haifa Bay, Israel

    Energy Technology Data Exchange (ETDEWEB)

    Hornung, H.; Krumgalz, B.S.; Cohen, Y.

    1984-01-01

    Total mercury concentrations were determined in surficial sediments, eleven species of benthic organisms and six species of fish from Haifa Bay, Israel. The results show that essentially all of the shallow water zone of the Bay receives anthropogenic mercury. A mercury-cell chlor-alkali plant was identified as the source of pollution. Surficial sediments in vicinity of the plant, containing up to 0.99 micro-g Hg/g dry weight, were up to 157 times enriched in mercury relative to an unpolluted area. Mercury levels in the benthic organisms reflected the levels in the sediments. Maximal concentrations reaching 38.7 and 18.2 micro-g Hg/g dry weight were found in the carnivorous gastropod mollusks Arcularia circumcinta and Arcularia gibbosula, respectively. In all fish species, specimens caught in Haifa Bay had higher mercury concentrations in the muscle tissue than specimens caught south of the Bay. A maximal value of 1.66 micro-g Hg/g wet weight was recorded in Diplodus sargus. 17 references, 3 figures, 3 tables.

  7. Dating upper plate normal fault slip events in Late Pleistocene and Holocene sediments of northern Chile

    Science.gov (United States)

    Robinson, R. A.; Binnie, S.; Gonzalez, G.; Cortés, J.

    2011-12-01

    In order to understand how subduction earthquakes along the Nazca-South America plate boundary affect upper plate faults in the coastal forearc of northern Chile, we are developing the first detailed paleoseismological study to characterize the Late Quaternary activity of the Mejillones and Salar del Carmen faults, located around 40 km north and 15 km east of Antofagasta, respectively. There is currently a lack of basic palaeo-seismological data on these and other upper plate faults, such as long term slip rates, amount of slip per event, palaeo-earthquake magnitude and recurrence intervals. This lack of knowledge impedes understanding of how large subduction earthquakes, occurring at depths of around 50 km in this region, relate to upper plate seismicity and deformation. We have used OSL dating of fault-related sediments, and cosmogenic-ray nuclide dating of terrace surfaces, to constrain slips rates over the last 45 ka. Several trenches were excavated across both faults in order to expose and log the most recent fault-related sediments. In the hanging wall of these normal faults, vertically stacked colluvial wedges and hillslope deposits are the product of discrete slip events and post-slip fault scarp degradation. Multiple trenches along each fault permit the spatial variability in slip amount and fault-related sedimentation to be investigated. Long-term slip rates have been measured using cosmogenic-ray nuclide exposure dating of the alluvial terraces offset by the Mejillones Fault. OSL dating of the fault-related sediments in the trenches has been used to compare the ages of individual slip events on both faults, and the age of events recorded along the trace of each fault. The application of both cosmogenic-ray nuclide and OSL methods in this type of setting (hyper-arid with low erosion rates, yet tectonically active) is non-trivial, due to cosmogenic inheritance accumulated in cobbles on the terrace surfaces, low sensitivity of the quartz for OSL dating, and

  8. Geochemistry and mineralogy of recent sediments of Guanabara Bay (NE sector and its major rivers - Rio de Janeiro State - Brazil

    Directory of Open Access Journals (Sweden)

    FARIA MARCIA DE MELO

    2001-01-01

    Full Text Available Geochemical and clay mineralogical studies of bottom sediments collected along the Macacu and Caceribu rivers and Guanabara Bay were carried out in order to investigate the relationship between major source areas and recent sediments of the bay. Clay mineralogy includes different groups with selective distribution conditioned by geomorphic features and depositional settings. Micaceous clay minerals are abundant near parent rock in the upper course, whereas kaolinite derived from varied sources is gradually concentrated towards the estuary. In the Guanabara Bay, kaolinite accumulates near river mouths, while micaceous clay minerals are converted into mixed layers in the estuary. Analyses of heavy metal contents reveal higher levels of Zn and Cu in sediments of the bay than in river sediments. Profiles along rivers indicate a downstream decrease of heavy metals, whereas in the bay geochemical trends display greater variations. In general river mouth sediments present the lowest concentrations. At the north and east of Paquetá Island anomalous areas with the highest heavy metal contents occur. Cu tends to concentrate in < 2mum grain-size fraction and indicates an association with micaceous clay minerals in the upper river course. However, Cu retention seems to be further controlled by other components of bottom sediments due to changes in physical and chemical conditions of the estuarine environment. Zn shows unstable behavior along the rivers and concentrates in the bay. Pb displays small variations from river to bay sediments, and accumulates mainly in the < 63mum grain-size fraction without any association with clay mineral. Geoaccumulation indexes of Cu, Pb and Zn classify the study area as unpolluted in both studied rivers and in the NE sector of the bay, though the enrichment factors are higher in the bay. The study does not indicate those rivers as major sources of heavy metal pollution to the bay.

  9. Biochemical and microbial features of shallow marine sediments along the Terra Nova Bay (Ross Sea, Antarctica)

    Science.gov (United States)

    Baldi, Franco; Marchetto, Davide; Pini, Francesco; Fani, Renato; Michaud, Luigi; Lo Giudice, Angelina; Berto, Daniela; Giani, Michele

    2010-09-01

    Shallow marine sediments were collected from seven stations (three of which located at Gerlache Inlet, two at Tethys Bay, one at Adelie Cove and one just beneath the Italian Research Base) along the Terra Nova Bay coast (Ross Sea, Antarctica). Their chemical, biochemical and microbiological properties were studied in order to provide further insights in the knowledge of this Antarctic benthic ecosystem. Overall, the organic carbon (OC) represented the major fraction of total carbon (TC) and displayed concentrations similar to or slightly lower than those previously measured in Antarctic bottom sediments. The biopolymeric carbon within OC ranged from 4.1% to 19.9% and showed a wide trophic range (65-834 μg g -1 d.w.). Proteins (PRT) represented on average the main biochemical class contributing to labile organic carbon, followed by lipids (LIP) and carbohydrates (CHO). The activity of aminopeptidase, β- D-glucosidase, alkaline phosphatase and esterase was checked, giving the highest values at Tethys Bay and at the deepest water sediments. The principal component analysis, which was computed considering physical, chemical (elemental and biochemical sedimentary composition) and microbiological parameters (including bacterial abundance, ectoenzymatic activities, T-RFs richness and diversity indices), allowed to obtain two main clusters ("Tethys Bay" and "other stations"). Based on data obtained, two representative 16S rRNA clone libraries using samples from Tethys Bay and Gerlache Inlet were constructed. The sequences of 171 clones were compared to those available in public databases to determine their approximate phylogenetic affiliations. Both aerobic and anaerobic bacteria were disclosed, with the majority of them affiliated with the Gamma- and Deltaproteobacteria, Bacteroidetes and Acidobacteria. The occurrence of strictly anaerobic bacteria suggests that sediments might also undergo anoxic conditions that, in turn, could favor the accumulation of PRT in respect

  10. [Distribution patterns of heavy metals in surface sediments of the Quanzhou Bay and environmental quality assessment].

    Science.gov (United States)

    Li, Yun-hai; Chen, Jian; Huang, Cai-bin; Wang, Ai-jun; Li, Dong-yi

    2010-04-01

    The concentrations of 7 heavy metals were determined in 48 surface sediments in the Quanzhou Bay by an inductively coupled plasma mass spectroscopy (ICP-MS). The average contents of Cr, Ni, Cu, Zn, As, Cd and Pb are 47.66, 52.2, 30.86, 111.6, 5.29, 0.399 and 50.3 microg x g(-1), respectively. The Cd, Pb, Zn and As were mainly discharged into the Quanzhou Bay by Jinjiang River, while the materials near the Bay might supply a considerable amount of Cr, Ni and Cu. The result of the multi-analysis ecological risk index analyses revealed that Cr, Ni, Cu, Zn, Pb and As were moderately contaminated and presented low potential ecological risk, while Cd was heavily contaminated and raised high potential ecological risk. In general, moderately contaminated and potential ecological risk were occurred in whole Quanzhou Bay with the dominated polluted metals were Ni and Cd. The heavily contaminated area was corresponded to the high potential ecological risk area, which located at the confluent area of Jinjiang River and Luoyangjiang River. From the results of this study, we conclude that the Quanzhou Bay has been heavily polluted by heavy metals, therefore much environmental control should be continued and strengthen to Quanzhou Bay and its adjacent areas.

  11. The mineralogy and chemistry of fine-grained sediments, Morphou Bay, Cyprus

    Directory of Open Access Journals (Sweden)

    C. Neal

    2002-01-01

    Full Text Available The mineralogy and chemistry of the less than 20μm fraction of marine sediments at Morphou Bay, north-west Cyprus, are presented to characterise fine-grained sediment supplies from basic and ultrabasic rocks of the Troodos Massif within a typological setting. The sediments comprise a mixture of smectite, illite, kaolinite and iron rich chlorite. They also contain amorphous iron oxides/hydroxides, calcite (with some magnesium substitution for calcium and an amphibole. Spatial patterns in mineralogy occur: the near-shore sediments are rich in smectite, chlorite, amphibole and amorphous iron oxides/hydroxides, while the offshore sediments are rich in illite and calcite. The sediments are calcium, magnesium, iron, aluminium and potassium bearing, due to the presence of significant amounts of calcite (for Ca, clay minerals and aluminium and iron oxides/hydroxides. Potassium is present within the micaceous mineral illite, but it is also contained within other phases that are difficult to pinpoint. Statistical analysis reveals that the chemical composition of the sediments broadly follows the mineralogy with the dominant feature being related to spatial changes in the mineralogy. The patterns of change reflect a three component mix of clay-sized sediment types: (1 localised lithogenous sources rich in smectite with subsidiary amounts of amorphous iron oxides/hydroxides and amphibole, from Cyprus, the Troodos in particular, (2 illite rich and smectite chlorite and chlorite bearing material of lithogenous origin from other parts of the eastern Mediterranean and (3 calcite, mainly of marine origin. Keywords: smectite, illite, chlorite, kaolinite, calcite, sediments, Morphou Bay, Troodos, Cyprus, Mediterranean, calcium, potassium, magnesium, iron, silicon, phosphorus.

  12. Sediment Sampling for Poly-Aromatic Hydrocarbons (PAHs) in Mobile Bay and Mississippi Sound in 2013 (NODC Accession 0116480)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Sediment samples were collected at ten sites within Mobile Bay and Mississippi Sound on January 28, 2013, for PAH analysis. All samples tested were below detection...

  13. Sediment Dwelling Benthos as Indicator Species for Pollution Monitoring of Mamala Bay, Oahu, Hawaii, 1993-1994 (NODC Accession 9900121)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A multifaceted study of the sediment dwelling benthos was conducted in Mamala Bay to identify suitable species as indicators of sewage enrichment. There are five...

  14. Spatial and temporal distribution and pollution assessment of trace metals in marine sediments in Oyster Bay, NSW, Australia.

    Science.gov (United States)

    Alyazichi, Yasir M; Jones, Brian G; McLean, Errol

    2015-01-01

    The disposal of untreated urban and industrial wastewater has a deleterious effect on both the water and sediment quality of Oyster Bay located in south Sydney, Australia. The present investigation was undertaken to evaluate the potential pollution of marine sediments in Oyster Bay. The results of metals were compared with adverse biological effect values effect range low (ERL) and effect range median (ERM). Spatial distribution of trace metals was estimated by applying geographic information system. The results indicated that the sediments were polluted with Cu, Zn, As and Pb, which exceeded ERL levels. However, these metals were still below ERM values, and other metals Cr and Ni were below ERL. Moreover, the highest concentrations of metals were around discharge points and in the inner bay. Further, trace metals could be attributed to human activities within the bay as they declined in concentrations with increasing sediment depth.

  15. Copper and Other Contaminants in King's Bay and Crystal River (Florida) Sediments: Implications for Impact on the West Indian Manatee

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Contaminant concentrations were measured in 25 sediment samples collected from King's Bay, the headwaters of the Crystal River, Florida. Total organic carbon content...

  16. Trace element residues in water, sediments, and organs of Savacu (Nycticorax nycticorax from Sepetiba Bay, Rio de Janeiro, Brazil

    Directory of Open Access Journals (Sweden)

    Marco Aurélio P. Horta

    2010-04-01

    Full Text Available Heavy metal (Cr, Cd, Zn, Cu, Ni, Pb concentrations in water, sediment and organs of Savacu, Nycticorax nycticorax were analyzed. Samples of water and sediment were collected from seven stations along Sepetiba Bay, and experimental animals, also were collected in the study area. This bay receives effluents discharges from heavily industrialized and highly populated settlements. Samples of water, sediment and Savacu were processed and analyzed for heavy metals and the results showed that these concentrations in sediment were higher than in water. The exposure to metals either in the water or by the effect of bioaccumulation in the food chain is reflected in the results obtained with animals’ test.

  17. Mineral composition of soils and bottom sediments in bays of Novaya Zemlya

    Science.gov (United States)

    Krupskaya, V. V.; Miroshnikov, A. Yu.; Dorzhieva, O. V.; Zakusin, S. V.; Semenkov, I. N.; Usacheva, A. A.

    2017-01-01

    We have analyzed the specific features of the mineralogical composition of bottom sediments of Blagopoluchiya, Tsivol'ki, and Abrosimov bays and soils on Cape Zhelaniya and the coasts of Abrosimov and Stepovoi bays. The data were obtained during two scientific expeditions of the R/V Professor Shtokman in 2014 (cruise 128) and R/V Akademik Mstislav Keldysh in 2015 (cruise 63). These investigations revealed patterns in the transportation of terrigenous material in the coastal zone of the bays: a decrease in the share of nonclay minerals and an increase in that of clay minerals with distance from shore. The increase in kaolinite and smectite content in soil horizons is related to biochemical weathering, while illite is mainly formed as a result of physical weathering.

  18. Regional Sediment Management (RSM) Strategy for Mobile Bay, Alabama

    Science.gov (United States)

    2015-04-01

    sediment and may have long-term negative effects. Beneficial use (BU) activities were reauthorized by WRDA 96 which states that “for the Mobile Harbor... refraction and shoaling, current-induced refraction and shoaling, depth- and steepness-limited wave breaking, wind-wave generation, wave-wave...mandates demonstration that the material requires no physical, biological , or chemical testing. Key elements of this strategy emphasize connection

  19. Butyltin speciation in sediments from Todos os Santos Bay (Bahia, Brazil by GC-PFPD

    Directory of Open Access Journals (Sweden)

    Juliana Feitosa Felizzola

    2008-01-01

    Full Text Available Butyltin compounds were investigated in surface sediments from 17 stations in Todos os Santos Bay. Analytical conditions for organotin determination in marine sediments were optimized for GC with pulsed flame photometric detection. Detection limits were: 5.4 µg kg-1 for TBT; 0.2 µg kg-1 for DBT; and 2.1 µg kg-1 for MBT, using a 610-nm filter. In general, TBT concentrations were low and in the range of

    sediments. The presence of paint particles in the sediments and degradation in the water column during resuspension events followed by removal of the more soluble DBT and MBT may explain these observations.

  20. Implications of excess 210Pb and 137Cs in sediment cores from Mikawa Bay, Japan

    Institute of Scientific and Technical Information of China (English)

    LU Xueqiang; MATSUMOTO Eiji

    2009-01-01

    Four sediment cores were collected from Mikawa Bay, Japan, and excess 210Pb and 137Cs were measured by gamma spectrometry. Sedimentation rates for the four cores were determined by 210Pb method. The sedimentation rate range is 0.10--0.70 g/(cm2·year). The bio-mixing depth for each core is less than 7.0 cm, and was determined by the excess 210Pb profiles as well. Therefore, the bioturbation is slight. The 210Pb-derived dates coincide with the results from 137Cs geochronology. Acceleration in sedimentation rate due to environmental alteration has been found in cores A2.5 and 05AS8, representing two depocenters due to their topography. Evidence of the Tokai Flood in 2000 was found in core 05AS8 according to the profiles of both radioisotopes and trace metals.

  1. Trace metals in the surface sediments of the intertidal Jiaozhou Bay, China: Sources and contamination assessment.

    Science.gov (United States)

    Xu, Fangjian; Qiu, Longwei; Cao, Yingchang; Huang, Jingli; Liu, Zhaoqing; Tian, Xu; Li, Anchun; Yin, Xuebo

    2016-03-15

    The major (Al) and trace metal (Cu, Pb, Zn, Cr, Cd, and As) concentrations in 29 surface sediment samples from the intertidal Jiaozhou Bay (JZB) are evaluated to assess the contamination level. The results show that the overall sediment quality in the area has been obviously impacted by trace metal contamination. The geoaccumulation index and the enrichment factor values indicate that no Cr or Cu contamination has occurred on the whole, only a few stations have been polluted by As, and some areas have been polluted by Cd, Pb, and Zn. Principal component analysis suggests that the Cu, Pb, Zn, and Cd are derived from anthropogenic inputs and that Cr, As, Cu, and Zn are influenced by natural weathering processes. Cu and Zn may originate from both natural and anthropogenic sources. The contamination in the northeastern JZB is higher than that in other areas of the bay. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Environmental and ecological risk of heavy metals in the marine sediment from Dakhla Bay, Morocco.

    Science.gov (United States)

    Hakima, Zidane; Mohamed, Maanan; Aziza, Mouradi; Mehdi, Maanan; Meryem, El Barjy; Bendahhou, Zourarah; Jean-Francois, Blais

    2017-01-20

    Heavy metal assessment in Dakhla Bay (Atlantic coast) was carried out using different environmental and ecological indices. Heavy metal concentrations were measured using ICP-AES and were compared with consensus-based sediment quality guidelines. The distribution of heavy metal concentrations varies for the three groups: (i) lead distribution is dominated by its associations with copper and chromium. These elements have the same source, most probably related to anthropogenic activities. (ii) Nickel, zinc and cobalt are associated with aluminium and iron indicating their terrigenous origin (natural content), and (iii) cadmium concentration is related to upwelling currents. This paper systematically studied the distributions and pollution levels of heavy metals in sediment in the coastal areas in Dakhla Bay, which is of scientific significance, to discuss the changing rules and the affecting factors of the harmful heavy metals and can be adopted for reference to other coastal areas.

  3. Environmental control on anaerobic oxidation of methane in the gassy sediments of Eckernforde Bay (German Baltic)

    DEFF Research Database (Denmark)

    Treude, T.; Kruger, M.; Boetius, A.

    2005-01-01

    We investigated the effect of seasonal environmental changes on the rate and distribution of anaerobic oxidation of methane (AOM) in Eckernforde Bay sediments (German Baltic Sea) and identified organisms that are likely to be involved in the process. Surface sediments were sampled during September...... the warm productive season and to a slightly deeper AOM zone during the cold winter season. Rising methane bubbles apparently fed AOM above the sulfate-methane transition. Methanosarcinales-related anaerobic methanotrophs (ANME-2), identified with fluorescence in situ hybridization, is suggested to mediate...

  4. [Distribution of matrix-bound phosphine in surface sediments of Jinpu Bay].

    Science.gov (United States)

    You, Li-Li; Zong, Hai-Bo; Zhang, Shu-Fang; Yin, Guo-Yu; Li, Tao; Hou, Li-Jun

    2013-10-01

    This work investigated the distribution of matrix-bound phosphine in surface sediments of Jinpu Bay and associated environmental factors in summer, using the gas chromatography combined with a pulsed flame detector (GC-PFPD). It showed that phosphine ubiquitously presented in the sediments of Jinpu Bay. Contents of matrix-bound phosphine varied between 62. 58 and 190. 81 ng.kg-1, with the average value of 114.42 ng.kg-1. In addition, the spatial distribution of matrix-bound phosphine indicated that matrix-bound phosphine in inshore sediments had relatively higher contents than those in offshore sediments. Statistical analysis showed that matrix-bound phosphine significantly related to organic phosphorus and alkaline phosphatase activity ( R = 0. 882, P = 0. 01; R = 0. 819, P =0. 023). However, there were no correlations between matrix-bound phosphine and organic nitrogen, inorganic phosphorus and sediment grain sizes. These results implied that accumulation and distribution of matrix-bound phosphined were mainly affected by the decomposition of organic phosphorus by microorganisms.

  5. Distribution Characteristics of Heavy Metals and Grain Size of Sediments from Hailing Bay, China

    Institute of Scientific and Technical Information of China (English)

    QIU Yaowen; ZHU Liangsheng; LI Manqiu

    2005-01-01

    The geochemical properties of sediment in the nearby seawater areas of Hailing Bay of the western Guangdong province were first time investigated in the dry period of 2001 and the flood period of 2002, respectively. The temporal and spatial characteristics of Cu, Pb, Zn, Cd and Hg concentrations, organic carbon and total sulfides contents, and granulometric distribution in the surface sediment from the Hailing Bay were analyzed. Results demonstrated that there were no remarkable changes in the composition of sediment between the dry period and the flood period;the average concentrations of Cu, Pb, Zn, Cd and Hg were 32.1 ± 17.5, 36.1 ± 10.0,respectively; surface sediments were dominated by clayey silt and sand, and their mean grain size was 4.62 ± 2.36 φ and in the range 0.52-7.55 φ; there existed obvious correlation between the concentrations of Cu, Pb, Zn and Hg, and among Cu, Pb, Zn and Hg concentrations, organic carbon contents and grain size of sediments.

  6. Spatial distribution and source apportionment of PAHs in marine surface sediments of Prydz Bay, East Antarctica.

    Science.gov (United States)

    Xue, Rui; Chen, Ling; Lu, Zhibo; Wang, Juan; Yang, Haizhen; Zhang, Jie; Cai, Minghong

    2016-12-01

    This paper reports the concentrations of polycyclic aromatic hydrocarbons (PAHs) in marine sediments sampled from Prydz Bay, East Antarctica. Total PAH concentrations ranged from 12.95 to 30.93 ng/g, with a mean of 17.99 ± 5.57 ng/g. Two- and three-ring PAHs were the most abundant compounds found at the majority of the sampling stations of Prydz Bay. Long-range atmospheric transportation was found to play an important role in determining the spatial distribution of PAHs in the sediments sampled here. However, transport by ocean currents and release from melting glaciers were also found to influence PAH distributions in the sediments of East Antarctica. The vertical migration of PAHs in sediments showed a decreasing trend with depth, with higher concentrations in the relatively shallow-water regions (1000 m) of the Amery Basin and associated Canyons, respectively. A Pearson correlation analysis between PAH concentrations and sediment parameters demonstrated that PAHs has poor correlations with grain size, but has positive correlation with total organic carbon, indicated complex processing during transfer to remote environments. The results of qualitative and quantitative analyses indicate that the PAHs sampled here were derived mainly from a mixture of biomass combustion, traffic emissions, and petrogenic sources.

  7. Paleontological interpretations of crater processes and infilling of synimpact sediments from the Chesapeake Bay impact structure

    Science.gov (United States)

    Self-Trail, Jean M.; Edwards, Lucy E.; Litwin, Ronald J.

    2009-01-01

    Biostratigraphic analysis of sedimentary breccias and diamictons in the Chesapeake Bay impact structure provides information regarding the timing and processes of late-stage gravitational crater collapse and ocean resurge. Studies of calcareous nannofossil and palynomorph assemblages in the International Continental Scientific Drilling Program (ICDP)–U.S. Geological Survey (USGS) Eyreville A and B cores show the mixed-age, mixed-preservation microfossil assemblages that are typical of deposits from the upper part of the Chesapeake Bay impact structure. Sparse, poorly preserved, possibly thermally altered pollen is present within a gravelly sand interval below the granite slab at 1392 m in Eyreville core B, an interval that is otherwise barren of calcareous nannofossils and dinocysts. Gravitational collapse of water- saturated sediments from the transient crater wall resulted in the deposition of sediment clasts primarily derived from the nonmarine Cretaceous Potomac Formation. Collapse occurred before the arrival of resurge. Low pollen Thermal Alteration Index (TAI) values suggest that these sediments were not thermally altered by contact with the melt sheet. The arrival of resurge sedimentation is identified based on the presence of diamicton zones and stringers rich in glauconite and marine microfossils at 866.7 m. This horizon can be traced across the crater and can be used to identify gravitational collapse versus ocean-resurge sedimentation. Glauconitic quartz sand diamicton dominates the sediments above 618.2 m. Calcareous nannofossil and dino-flagellate data from this interval suggest that the earliest arriving resurge from the west contained little or no Cretaceous marine input, but later resurge pulses mined Cretaceous sediments east of the Watkins core in the annular trough. Additionally, the increased distance traveled by resurge to the central crater in turbulent flow conditions resulted in the disaggregation of Paleogene unconsolidated sediments. As

  8. First record of Cymatium keenae Beu, 1970 (Mollusca: Ranellidae) from Antofagasta Bay, northern Chile, in connection with El Niño events

    Science.gov (United States)

    Ashton, Tom; Riascos, Jose M.; Pacheco, Aldo

    2008-03-01

    Cymatium ( Monoplex) keenae Beu, 1970, the neopolitan triton, is a Ranellidae predator distributed in tropical and subtropical waters. In this study we report this species for the first time in Antofagasta Bay, northern Chile. Adult specimens have been found since June 2003 at depths ranging from 5 to 15 m in La Rinconada Marine Reserve (23°28'18″S, 70°30'46″W) in Antofagasta Bay, near a scallop farming facility. The present findings clearly extend the geographic range of C. keenae, which previously had been reported from La Paz, Gulf of California (Mexico) to Galápagos Islands (Ecuador) in the SE Pacific. Previous evidence strongly suggests that the intrusion of this tropical immigrant can be related to warm El Niño episodes. We analyze the key role of the oceanographic characteristics of Antofagasta Bay as potential temporal refuge for this species.

  9. Coastal lake sediments reveal 5500 years of tsunami history in south central Chile

    Science.gov (United States)

    Kempf, Philipp; Moernaut, Jasper; Van Daele, Maarten; Vandoorne, Willem; Pino, Mario; Urrutia, Roberto; De Batist, Marc

    2017-04-01

    We present an exceptionally long and continuous coastal lacustrine record of ∼5500 years from Lake Huelde on the west coast of Chiloé Island in south central Chile. The study area is located within the rupture zone of the giant 1960 CE Great Chilean Earthquake (MW 9.5). The subsequent earthquake-induced tsunami inundated Lake Huelde and deposited mud rip-up clasts, massive sand and a mud cap in the lake. Long sediment cores from 8 core sites within Lake Huelde reveal 16 additional sandy layers in the 5500 year long record. The sandy layers share sedimentological similarities with the deposit of the 1960 CE tsunami and other coastal lake tsunami deposits elsewhere. On the basis of general and site-specific criteria we interpret the sandy layers as tsunami deposits. Age-control is provided by four different methods, 1) 210Pb-dating, 2) the identification of the 137Cs-peak, 3) an infrared stimulated luminescence (IRSL) date and 4) 22 radiocarbon dates. The ages of each tsunami deposit are modelled using the Bayesian statistic tools of OxCal and Bacon. The record from Lake Huelde matches the 8 regionally known tsunami deposits from documented history and geological evidence from the last ∼2000 years without over- or underrepresentation. We extend the existing tsunami history by 9 tsunami deposits. We discuss the advantages and disadvantages of various sedimentary environments for tsunami deposition and preservation, e.g. we find that Lake Huelde is 2-3 times less sensitive to relative sea-level change in comparison to coastal marshes in the same region.

  10. Sediment Chemistry and Toxicity in Barnegat Bay, New Jersey: Pre- and Post- Hurricane Sandy, 2012-2013.

    Science.gov (United States)

    Romanok, Kristin; Szabo, Zoltan; Reilly, Timothy J.; Defne, Zafer; Ganju, Neil K.

    2016-01-01

    Hurricane Sandy made landfall in Barnegat Bay, October, 29, 2012, damaging shorelines and infrastructure. Estuarine sediment chemistry and toxicity were investigated before and after to evaluate potential environmental health impacts and to establish post-event baseline sediment-quality conditions. Trace element concentrations increased throughout Barnegat Bay up to two orders of magnitude, especially north of Barnegat Inlet, consistent with northward redistribution of silt. Loss of organic compounds, clay, and organic carbon is consistent with sediment winnowing and transport through the inlets and sediment transport modeling results. The number of sites exceeding sediment quality guidance levels for trace elements tripled post-Sandy. Sediment toxicity post-Sandy was mostly unaffected relative to pre-Sandy conditions, but at the site with the greatest relative increase for trace elements, survival rate of the test amphipod decreased (indicating degradation). This study would not have been possible without comprehensive baseline data enabling the evaluation of storm-derived changes in sediment quality.

  11. Sediment chemistry and toxicity in Barnegat Bay, New Jersey: Pre- and post-Hurricane Sandy, 2012-13.

    Science.gov (United States)

    Romanok, Kristin M; Szabo, Zoltan; Reilly, Timothy J; Defne, Zafer; Ganju, Neil K

    2016-06-30

    Hurricane Sandy made landfall in Barnegat Bay, October, 29, 2012, damaging shorelines and infrastructure. Estuarine sediment chemistry and toxicity were investigated before and after to evaluate potential environmental health impacts and to establish post-event baseline sediment-quality conditions. Trace element concentrations increased throughout Barnegat Bay up to two orders of magnitude, especially north of Barnegat Inlet, consistent with northward redistribution of silt. Loss of organic compounds, clay, and organic carbon is consistent with sediment winnowing and transport through the inlets and sediment transport modeling results. The number of sites exceeding sediment quality guidance levels for trace elements tripled post-Sandy. Sediment toxicity post-Sandy was mostly unaffected relative to pre-Sandy conditions, but at the site with the greatest relative increase for trace elements, survival rate of the test amphipod decreased (indicating degradation). This study would not have been possible without comprehensive baseline data enabling the evaluation of storm-derived changes in sediment quality.

  12. Shipboard magnetic field "noise" reveals shallow heavy mineral sediment concentrations in Chesapeake Bay

    Science.gov (United States)

    Shah, Anjana K.; Vogt, Peter R.; Rosenbaum, Joseph G.; Newell, Wayne; Cronin, Thomas M.; Willard, Debra A.; Hagen, Rick A.; Brozena, John; Hofstra, Albert

    2012-01-01

    Shipboard magnetic field data collected over Chesapeake Bay exhibit low-amplitude, short-wavelength anomalies that most likely indicate shallow concentrations of heavy mineral sediments. Piston core layers and black sand beach samples exhibit enhanced magnetic susceptibilities and carry remanent magnetization, with mineralogical analyses indicating ilmenite and trace magnetite and/or maghemite and hematite. The anomalies are subtle and would be filtered as noise using traditional approaches, but can instead be highlighted using spectral methods, thus providing nearly continuous coverage along survey tracks. The distribution of the anomalies provides constraints on relevant sorting mechanisms. Comparisons to sonar data and previous grab samples show that two of three areas surveyed exhibit short-wavelength anomalies that are clustered over sand-covered areas, suggesting initial sorting through settling mechanisms. This is supported by a correlation between core magnetic susceptibility and grain size. Near the Choptank River, where sediment resuspension is wave-dominated, anomalies show a sharp decrease with seafloor depth that cannot be explained by signal attenuation alone. In Pocomoke Sound, where both tidal currents and wave-action impact sediment resuspension, anomalies show a more gradual decrease with depth. Near the mouth of the bay, where there is a higher influx of sediments from the continental shelf, short-wavelength anomalies are isolated and do not appear to represent heavy mineral sand concentrations. These combined observations suggest the importance of further sorting by erosional processes in certain parts of the bay. Additionally, comparisons of these data to cores sampling pre-Holocene sediments suggest that the sorting of heavy minerals in higher energy, shallow water environments provides a mechanism for correlations between core magnetic susceptibility and sea-level changes.

  13. Presence of selected chemicals of emerging concern in water and bottom sediment from the St. Louis River, St. Louis Bay, and Superior Bay, Minnesota and Wisconsin, 2010

    Science.gov (United States)

    Christensen, Victoria G.; Lee, Kathy E.; Kieta, Kristen A.; Elliott, Sarah M.

    2012-01-01

    The St. Louis Bay of Lake Superior receives substantial urban runoff, wastewater treatment plant effluent, and industrial effluent. In 1987, the International Joint Commission designated the St. Louis Bay portion of the lower St. Louis River as one of the Great Lakes Areas of Concern. Concerns exist about the potential effects of chemicals of emerging concern on aquatic biota because many of these chemicals, including endocrine active chemicals, have been shown to affect the endocrine systems of fish. To determine the occurrence of chemicals of emerging concern in the St. Louis River, the St. Louis Bay, and Superior Bay, the U.S. Geological Survey in cooperation with the Minnesota Pollution Control Agency and the Wisconsin Department of Natural Resources collected water and bottom-sediment samples from 40 sites from August through October 2010. The objectives of this study were to (1) identify the extent to which chemicals of emerging concern, including pharmaceuticals, hormones, and other organic chemicals, occur in the St. Louis River, St. Louis Bay, and Superior Bay, and (2) identify the extent to which the chemicals may have accumulated in bottom sediment of the study area. Samples were analyzed for selected wastewater indicators, hormones, sterols, bisphenol A, and human-health pharmaceuticals. During this study, 33 of 89 chemicals of emerging concern were detected among all water samples collected and 56 of 104 chemicals of emerging concern were detected in bottom-sediment samples. The chemical N,N-diethyl-meta-toluamide (DEET) was the most commonly detected chemical in water samples and 2,6-dimethylnaphthalene was the most commonly detected chemical in bottom-sediment samples. In general, chemicals of emerging concern were detected at a higher frequency in bottom-sediment samples than in water samples. Estrone (a steroid hormone) and hexahydrohexamethyl cyclopentabensopyran (a synthetic fragrance) were the most commonly detected endocrine active chemicals in

  14. Delineating incised stream sediment sources within a San Francisco Bay tributary basin

    Science.gov (United States)

    Bigelow, Paul; Benda, Lee; Pearce, Sarah

    2016-07-01

    Erosion and sedimentation pose ubiquitous problems for land and watershed managers, requiring delineation of sediment sources and sinks across landscapes. However, the technical complexity of many spatially explicit erosion models precludes their use by practitioners. To address this critical gap, we demonstrate a contemporary use of applied geomorphometry through a straightforward GIS analysis of sediment sources in the San Francisco Bay Area in California, USA, designed to support erosion reduction strategies. Using 2 m lidar digital elevation models, we delineated the entire river network in the Arroyo Mocho watershed (573 km2) at the scale of ˜ 30 m segments and identified incised landforms using a combination of hillslope gradient and planform curvature. Chronic erosion to the channel network was estimated based on these topographic attributes and the size of vegetation, and calibrated to sediment gage data, providing a spatially explicit estimate of sediment yield from incised channels across the basin. Rates of erosion were summarized downstream through the channel network, revealing patterns of sediment supply at the reach scale. Erosion and sediment supply were also aggregated to subbasins, allowing comparative analyses at the scale of tributaries. The erosion patterns delineated using this approach provide land use planners with a robust framework to design erosion reduction strategies. More broadly, the study demonstrates a modern analysis of important geomorphic processes affected by land use that is easily applied by agencies to solve common problems in watersheds, improving the integration between science and environmental management.

  15. 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.

  16. {sup 137}Cs in marine sediments of Admiralty Bay, King George Island, Antarctica

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Paulo Alves de Lima [Instituto Oceanográfico, Universidade de São Paulo (IO-USP), Pça. do Oceanográfico, 191, Butantã, SP, 05508 900 (Brazil); Ribeiro, Andreza Portella, E-mail: andrezpr@usp.br [Instituto Oceanográfico, Universidade de São Paulo (IO-USP), Pça. do Oceanográfico, 191, Butantã, SP, 05508 900 (Brazil); Mestrado de Gestão Ambiental e Sustentabilidade, Universidade Nove de Julho (UNINOVE), Avenida Francisco Matarazzo, 612, prédio C, andar térreo, Água Branca, São Paulo, SP, 05001 100 (Brazil); Nascimento, Mylene Giseli do; Martins, Cesar de Castro [Centro de Estudos do Mar, Universidade Federal do Paraná (CEM-UFPR), Av. Beira-mar, no number, Balneário Pontal do Sul, Pontal do Paraná, PR, 83255 971 (Brazil); Mahiques, Michel Michaelovitch de; Montone, Rosalinda Carmelo; Figueira, Rubens Cesar Lopes [Instituto Oceanográfico, Universidade de São Paulo (IO-USP), Pça. do Oceanográfico, 191, Butantã, SP, 05508 900 (Brazil)

    2013-01-15

    The radionuclide cesium-137 ({sup 137}Cs) is produced exclusively by anthropogenic processes and primarily by nuclear explosions. This study determined the reference inventory that is {sup 137}Cs associated with the element's original input, and utilized the levels of activity of this radionuclide previously measured in five sediment profiles collected from Admiralty Bay, Antarctica, to investigate the mobility of this element in the environment. {sup 137}Cs has a half-life of 30 years. Because of this, it is environmentally persistent and has been shown to accumulate in marine organisms. The mean reference inventory of this radionuclide in Admiralty Bay sediments, determined using high resolution gamma ray spectrometry, was 20.23 ± 8.94 Bq m{sup −2}, and within the ambient {sup 137}Cs activity range. A model of {sup 137}Cs diffusion–convection was applied to data collected from 1 cm intervals in sediment cores with the aim of providing insights with respect to this element's behavior in sediments. Model results showed a significant correlation between measured and modeled values using the concentrations of {sup 137}Cs, and estimated input into the system from the global fallout of past nuclear tests and expected values based on local sedimentation rates. Results highlight the importance of accounting for the vertical diffusion of {sup 137}Cs in marine sediments when used as a tracer for environmental processes and for assessing potential bioavailability. - Highlights: ► Cesium-137 ({sup 137}Cs) is produced exclusively by anthropogenic processes. ► A model of diffusion–convection simulated {sup 137}Cs environmental behavior. ► This is important for assessing the bioavailability of this toxic element. ► In Antarctica ice cover influenced the input to the sediments.

  17. Storm and fair-weather driven sediment-transport within Poverty Bay, New Zealand, evaluated using coupled numerical models

    Science.gov (United States)

    Bever, Aaron J.; Harris, Courtney K.

    2014-09-01

    The Waipaoa River Sedimentary System in New Zealand, a focus site of the MARGINS Source-to-Sink program, contains both a terrestrial and marine component. Poverty Bay serves as the interface between the fluvial and oceanic portions of this dispersal system. This study used a three-dimensional hydrodynamic and sediment-transport numerical model, the Regional Ocean Modeling System (ROMS), coupled to the Simulated WAves Nearshore (SWAN) wave model to investigate sediment-transport dynamics within Poverty Bay and the mechanisms by which sediment travels from the Waipaoa River to the continental shelf. Two sets of model calculations were analyzed; the first represented a winter storm season, January-September, 2006; and the second an approximately 40 year recurrence interval storm that occurred on 21-23 October 2005. Model results indicated that hydrodynamics and sediment-transport pathways within Poverty Bay differed during wet storms that included river runoff and locally generated waves, compared to dry storms driven by oceanic swell. During wet storms the model estimated significant deposition within Poverty Bay, although much of the discharged sediment was exported from the Bay during the discharge pulse. Later resuspension events generated by Southern Ocean swell reworked and modified the initial deposit, providing subsequent pulses of sediment from the Bay to the continental shelf. In this manner, transit through Poverty Bay modified the input fluvial signal, so that the sediment characteristics and timing of export to the continental shelf differed from the Waipaoa River discharge. Sensitivity studies showed that feedback mechanisms between sediment-transport, currents, and waves were important within the model calculations.

  18. Sediment Retention Dynamics and Vegetation Along Three Tributaries of the Chesapeake Bay

    Science.gov (United States)

    Ross, K.; Ross, K.; Hupp, C.; Alexander, L.; Alexander, L.

    2001-12-01

    Coastal Plain riparian wetlands in the Mid-Atlantic United States are the last place for sediment and contaminant storage before reaching critical estuarine and marine environments. The deteriorating health of the Chesapeake Bay has been attributed in part to elevated sediment loads. The purpose of this study is to investigate the effects of channelization and urbanization on sediment deposition and geomorphic processes along the Pocomoke and Chickahominy Rivers and Dragon Run, three Coastal Plain tributaries. Floodplain microtopography was surveyed in 100 x 100 m grids at three characteristic reaches along each river and woody vegetation analyses were conducted. Floodplain suspended sediment concentrations and short and long-term sedimentation rates were estimated at each reach using single stage sediment sampler arrays, clay pads and dendrogeomorphic techniques, respectively. Site hydroperiod and flow characteristics were determined from USGS gaging station records, floodplain water level recorders, and field observations. Channelized floodplain reaches along the Pocomoke River are flooded less frequently, have lower mineral sedimentation rates (2 mm/yr to 6 mm/yr) and woody species diversity than the unchannelized reaches. Along the Chickahominy River, floodplain wetlands close to urban centers are flooded more frequently, but have shorter hydroperiods (3.5 days/yr compared to more than 45 days/yr), lower sedimentation rates (1.8 mm/yr to 6.8 mm/yr), and lower woody species diversity (0.51 to 1.95 on the Shannon-Weiner diversity index) than floodplains further downstream. Suspended sediment delivery and deposition rates are significantly influenced by floodplain hydroperiod duration and channel-floodplain connectivity. These results suggest that understanding floodplain sediment dynamics and geomorphic processes with respect to dominant watershed landuse patterns is critical for effective water quality management and restoration efforts.

  19. Natural and anthropogenic sources of chemical elements in sediment profiles from the Admiralty Bay, Antarctica

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, A.P.; Figueira, R.C.L.; Silva, C.R.A.; Franca, E.J.; Mahiques, M.M.; Bicego, M.C.; Montone, R.C. [Universidade de Sao Paulo (IO/USP), SP (Brazil). Inst. Oceanografico; Martins, C.C. [Universidade Federal do Parana (UFPR), Pontal do Sul, PR (Brazil). Centro de Estudos do Mar; Scapin, M.A.; Scapin, V.O.; Figueiredo, A.M.G.; Ticianelli, R.B. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2010-07-01

    Full text: The Antarctic Continent and its surrounding Southern Ocean are the least known regions of the world, mainly due to the most unfavorable climatic conditions, in which sampling for environmental studies are quite difficult to be carried out. Admiralty Bay on the King George Island (Antarctica) hosts three research stations, Arctowski, Ferraz and Macchu Picchu, which are operate by Poland, Brazil and Peru, respectively. Therefore, human activities in this region require the use of fossil fuel as an energy source, which is also considered the main source of pollutants in the area. This work investigated the natural and anthropogenic inputs of chemical elements in sediment samples collected close to Ferraz Station, during the 25{sup th} Brazilian Antarctica Expedition in the 2006/2007 austral summer. Total concentrations of As, Zn and Sc were determined in sediment profiles by using the Instrumental Neutron Activation Analysis (INAA). The analytical technique employed to determine the major elements such as Fe, Al, Ca, Mn and Ti was X-ray fluorescence (XRF) spectroscopy. For estimating the sedimentation rate, High Resolution Gamma Ray Spectrometry was applied to determine {sup 137}Cs, after 30 days, to achieve secular equilibrium. According to the enrichment factor and the geochronology analysis, the most relevant enrichment was observed for As in the sediment samples, suggesting the increasing of its content due to the Brazilian activities in the Admiralty Bay. Despite some evidences of anthropogenic contribution, the study indicated low level of environmental risk for this region. (author)

  20. Source identification and assessment of sediment contamination of trace metals in Kogarah Bay, NSW, Australia.

    Science.gov (United States)

    Alyazichi, Yasir M; Jones, Brian G; McLean, Errol

    2015-02-01

    The distribution of trace metals (spatial and temporal) and sedimentary fractions were investigated to identify the concentrations and sources of trace metals within Kogarah Bay, NSW, Australia. A total of 59 surface sediments and six subsurface samples from core of the sediment were collected. The contamination factor and pollution load index indices used to evaluate environmental effects of trace metals. The study area was found to be uncontaminated with Cr and Ni, moderately contaminated with As and considerably contaminated with Cu, Zn and Pb. The concentrations of Cr and Ni were below both effect range low and effect range median, while As, Cu, Zn and Pb were slightly above effect range low. The highest concentrations of these trace metals such as Cu, Zn and Pb were found in the north, northwest and southeast of the bay, close to discharge points, stormwater outlets and around boatyards and watercrafts. The spatial distributions of metals were strongly related to muddy particles and organic matter. The temporal sediments of metals declined with increased sediment depth, which reflects accumulation of trace metals since European settlement in this area. Furthermore, the source of the trace metals was found to be stormwater outlets, gasoline fumes, boatyards and other human activities.

  1. Bacterial diversity, composition and temporal-spatial variation in the sediment of Jiaozhou Bay, China

    Institute of Scientific and Technical Information of China (English)

    LIU Xin; XIAO Tian; LUAN Qingshan; ZHANG Wenyan; WANG Mengqiang; YUE Haidong

    2011-01-01

    Studies on the diversity and distribution of bacterial populations will improve the overall understanding of the global patterns of marine bacteria and help to comprehend local biochemical processes and environments. We evaluated the composition and the dynamics of bacterial communities in the sediment of Jiaozhou Bay (China) using PCR-denaturing gradient gel electrophoresis (DGGE). Sediment samples were collected from 10 different sites in May, August, and November 2008 and in February 2009.There was significant temporal variation in bacterial community composition at all sites. However, the spatial variation was very small. The DGGE analyses of bacterial communities were used to divide the 10 stations into three types. Canonical correspondence analysis (CCA) revealed that the changes in bacterial communities were driven by sediment properties. Sequence analysis of DGGE band-derived 16S rRNA gene fragments revealed that the dominant bacterial groups in the sediment were of the classes γ-proteobacteria and δ-proteobacteria and phyla Bacteroidetes and Nitrospirae. Our results provide considerable insight into the bacterial community structure in Jiaozhou Bay, China.

  2. Reconstructing the rise of recent coastal anoxia; molybdenum in Chesapeake Bay sediments

    Science.gov (United States)

    Adelson, J.M.; Helz, G.R.; Miller, C.V.

    2001-01-01

    Sporadic, direct observations over a 50 yr period inadequately characterize the history of seasonal hypoxia and anoxia in Chesapeake Bay, alarge estuary threatened by eutrophication. Here, we undertake a reconstruction of 20th century oxygen depletion in this estuary using Mo concentrations in 210Pb-dated sediments; Cu concentrations are used to control for anthropogenic influences. Cores from the central channel display mild Mo enrichments above crustal backgrounds (up to 5 ??g/g) and strong Cu enrichments (up to 35 ??g/g). Temporally, Cu enrichment (mostly anthropogenic) began earlier and stabilized in the last two thirds of the 20th century. In contrast, Mo enrichment has grown during the last two thirds of the century. Molybdenum enrichment is mostly hydrogenic, except in a section of the channel that receives additional Mo from erosion of Early Miocene shore deposits. Two geochemical mechanisms promote Mo enrichment: Manganese refluxing concentrates dissolved MoO24- at the sediment-water interface and sulfide substitution into MoO24- produces thiomolybdates, which can be fixed by particles. The Mo enrichment mechanisms operate primarily during periods when bottom waters are anoxic and thiomolybdate formation can occur near the sediment-water interface. This implies a temporal coupling between water-column anoxia and Mo fixation even though fixation occurs only within sediments. The Mo enrichment profiles suggest that Chesapeake Bay has experienced growing O2 depletion since the first half of the 20th century, but especially after 1960. Copyright ?? 2001 Elsevier Science Ltd.

  3. Concentrations and distribution of mercury and other heavy metals in surface sediments of the Yatsushiro Sea including Minamata Bay, Japan.

    Science.gov (United States)

    Nakata, Haruhiko; Shimada, Hideaki; Yoshimoto, Maki; Narumi, Rika; Akimoto, Kazumi; Yamashita, Takayuki; Matsunaga, Tomoya; Nishimura, Keisuke; Tanaka, Masakazu; Hiraki, Kenju; Shimasaki, Hideyuki; Takikawa, Kiyoshi

    2008-01-01

    The concentrations and distribution of heavy metals, such as mercury, zinc, copper, lead, and iron in surface sediments from 234 stations of the Yatsushiro Sea including Minamata bay were investigated. High concentrations of mercury were found in sediments from Minamata bay and its vicinity, but the levels decreased gradually with distance from the bay. The concentrations of mercury in sediments decreased gradually from south to north of the Yatsushiro Sea. These imply the lack of movement of mercury from Minamata bay to the northern Yatsushiro Sea. The geographical profiles of zinc and copper were contrary to that found for mercury, indicating the presence of natural and anthropogenic sources of copper and zinc in the northern Yatsushiro Sea.

  4. Methodical Features of the Field Researches of the Anapa Bay-Bar Sediment Composition

    Science.gov (United States)

    Krylenko, Marina; Krylenko, Viacheslav; Gusakova, Anastasiya; Kosyan, Alisa

    2014-05-01

    Resort Anapa (Black Sea coast, Russia) holds leading positions in the Russian market of sanatorium-resort and children's recreation. The 50-200 m sandy beaches of Anapa bay-bar are the main value of the resort. Anapa bay-bar is an extensive accumulative sandy body having the length about 47 km. Obvious attributes of the beaches degradation demanding immediate measures on their protection and restoration are observed in last years. The main reason of degradation is beach material deficiency. To organize researches of the sediments of this extensive natural object is a difficult challenge. It is necessary to reduce number of tests to minimum. It is important to record differences of separate bay-bar sites and to receive comparable data for different seasons and years. Our researches showed that the grain-size sediment composition significantly depends of position on local relief. Consequently, researching of the alongshore change of the sediment size is effectual to realize at this morphological elements. Shelly detritus makes to 30% of total amount of beach sediments. It is necessary to consider that quantitative shell distribution along the coast significantly depends on a configuration of the coastline and an underwater relief. Quantity of the shells for cross-shore profile is maximal near coastline. For identification of the sediment sources and researching of their fluxes to use minerals markers (heavy minerals) is optimum. The maximum of heavy minerals concentration is characteristic for fraction 0.1-0.05mm at depth more 5 m. The maintenance of this fraction within other morphological zones isn't enough for the analysis or is excessively changeable. Use of the revealed features allowed to conduct the representative field researches of grain-size and mineral sediment composition for all morphological zones of underwater and coast part of the Anapa bay-bar. This methodic recommendations are workable for researches on others coast accumulative body. The work is

  5. Assessment of sediment pollution by metals. A case study from Cienfuegos Bay, Cuba.

    Science.gov (United States)

    Peña-Icart, Mirella; Mendiguchía, Carolina; Villanueva-Tagle, Margarita; Bolaños-Alvarez, Yoelvis; Alonso-Hernandez, Carlos; Moreno, Carlos; Pomares-Alfonso, Mario Simeón

    2017-02-15

    Sediments were grouped in three zones of the bay: two in the northern basin with higher metal contamination; and another in the southern basin, where lithogenic metals were predominant. Sediment pollution classification made using Index of geoaccumulation and Enrichment factor was consistent, indicating higher accumulation of Cd and Pb in the northern basin. The negative influence of activities linked to petrol was predicted by V/Ni and V/(Ni+V) ratios. Cd and Pb did not represent a potential risk; while Cu and Ni could be risky for biota in most sediment, according to Screening Quick Reference Tables (SQuiRTs). Comparison of bioavailable fraction of metals with references in SQuiRTs corroborated the low potential damage on the biota due to As, Cd, Pb, Cr, Zn; and a higher potential damage due to Cu; while an attenuation of the risk due to Ni predicted by SQuiRTs could be expected. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Mercury flux to estuarine sediments, derived from Pb-210 and Cs-137 geochronologies (Guaratuba Bay, Brazil)

    Energy Technology Data Exchange (ETDEWEB)

    Sanders, Christian J. [Departamento de Geoquimica, Universidade Federal Fluminense, 24020-007 Niteroi-RJ (Brazil)]. E-mail zinosanders@yahoo.com; Santos, Isaac R. [Department of Oceanography, Florida State University, Tallahassee, FL, 32306 (United States); Silva-Filho, Emmanoel V. [Departamento de Geoquimica, Universidade Federal Fluminense, 24020-007 Niteroi-RJ (Brazil); Patchineelam, Sambasiva R. [Departamento de Geoquimica, Universidade Federal Fluminense, 24020-007 Niteroi-RJ (Brazil)

    2006-09-15

    A sediment core from Guaratuba Bay was used to indicate possible Hg modifications to this coastal environment brought about by growing agricultural activity. Sedimentation rates were estimated to be 6.1 mm/year and 5.2 mm/year through {sup 21}Pb and {sup 137}Cs geochronologies, respectively. Mercury concentrations and organic matter ratios in the surface layers are greater than in the older sediments, supporting the hypothesis of anthropogenic enrichment. Results show that the Hg flux has raised more than twofold during the second half of the 20th century. These results point to the need for further studies to substantiate the hypothesis of anthropogenic enrichment and to quantify point sources of Hg to this estuary.

  7. Recent {sup 137}Cs deposition in sediments of Admiralty Bay, Antarctica

    Energy Technology Data Exchange (ETDEWEB)

    Sanders, Christian J., E-mail: zinosanders@yahoo.co [Departamento de Geoquimica, Universidade Federal Fluminense, 24020-007, Niteroi-RJ (Brazil); Santos, Isaac R. [Centre for Coastal Biogeochemistry, School of Environmental Science and Management, Southern Cross University, Lismore, NSW 2480 (Australia); Patchineelam, Sambasiva R. [Departamento de Geoquimica, Universidade Federal Fluminense, 24020-007, Niteroi-RJ (Brazil); Schaefer, Carlos [Departamento de Solos, Universidade Federal de Vicosa, 36570-000, Vicosa-MG (Brazil); Silva-Filho, Emmanoel V. [Departamento de Geoquimica, Universidade Federal Fluminense, 24020-007, Niteroi-RJ (Brazil)

    2010-05-15

    Cesium-137, radium-226 and lead-210 profiles of a 25 cm sediment core give an indication of recent changes in land-ocean interactions at a polar coastal environment (Admiralty Bay, King George Island, Antarctica). The linear sedimentation accumulation rate at the study site calculated from the unsupported {sup 210}Pb profile was 6.7 mm/year from 1965 to 2005. A 3.5-fold increase in {sup 137}Cs concentrations was observed in the top layer of this sediment core. This sharp increase seems to indicate a recent redistribution of fallout radionuclides previously deposited on soil, vegetation and snow. These results imply enhanced land-ocean interactions at this site likely as a result of climate change. Because our results are based on a single core, additional investigations are needed to confirm our observations.

  8. Sources of suspended-sediment flux in streams of the chesapeake bay watershed: A regional application of the sparrow model

    Science.gov (United States)

    Brakebill, J.W.; Ator, S.W.; Schwarz, G.E.

    2010-01-01

    We describe the sources and transport of fluvial suspended sediment in nontidal streams of the Chesapeake Bay watershed and vicinity. We applied SPAtially Referenced Regressions on Watershed attributes, which spatially correlates estimated mean annual flux of suspended sediment in nontidal streams with sources of suspended sediment and transport factors. According to our model, urban development generates on average the greatest amount of suspended sediment per unit area (3,928 Mg/km2/year), although agriculture is much more widespread and is the greatest overall source of suspended sediment (57 Mg/km2/year). Factors affecting sediment transport from uplands to streams include mean basin slope, reservoirs, physiography, and soil permeability. On average, 59% of upland suspended sediment generated is temporarily stored along large rivers draining the Coastal Plain or in reservoirs throughout the watershed. Applying erosion and sediment controls from agriculture and urban development in areas of the northern Piedmont close to the upper Bay, where the combined effects of watershed characteristics on sediment transport have the greatest influence may be most helpful in mitigating sedimentation in the bay and its tributaries. Stream restoration efforts addressing floodplain and bank stabilization and incision may be more effective in smaller, headwater streams outside of the Coastal Plain. ?? 2010 American Water Resources Association. No claim to original U.S. government works.

  9. Phosphate geochemistry, mineralization processes, and Thioploca distribution in shelf sediments off central Chile

    DEFF Research Database (Denmark)

    Holmkvist, Lars; Arning, Esther T.; Küster-Heins, Kathrin

    2010-01-01

    mineralization, and occurrence of dense communities of the filamentous sulfur bacteria, Thioploca spp., on the continental shelf off central Chile during the austral summer when high phytoplankton productivity and anoxic bottom water prevailed. Freshly deposited phytodetritus stimulated extremely high sulfate...

  10. Phosphate geochemistry, mineralization processes, and Thioploca distribution in shelf sediments off central Chile

    DEFF Research Database (Denmark)

    Holmkvist, Lars; Arning, Esther T.; Küster-Heins, Kathrin

    2010-01-01

    mineralization, and occurrence of dense communities of the filamentous sulfur bacteria, Thioploca spp., on the continental shelf off central Chile during the austral summer when high phytoplankton productivity and anoxic bottom water prevailed. Freshly deposited phytodetritus stimulated extremely high sulfate...

  11. Phosphorus speciation and its bioavailability in sediments of the Jiaozhou Bay

    Science.gov (United States)

    Kang, Xuming; Song, Jinming; Yuan, Huamao; Shi, Xin; Yang, Weifeng; Li, Xuegang; Li, Ning; Duan, Liqin

    2017-03-01

    Phosphorus (P) is an important macronutrient that can limit primary productivity in coastal marine ecosystems. In this study, four sediment cores were collected in the Jiaozhou Bay to study the phosphorus forms and their bioavailability, including exchangeable or loosely sorbed P (Ex-P), iron-bound P (Fe-P), authigenic P (Ca-P), detrital P (De-P) and organic P (OP), which were separated and quantified using a sequential extraction method (SEDEX). The results showed that the concentration of total P (TP) in core sediments ranged from 6.23 to 10.46 μmol/g, and inorganic P (IP) was the dominated P form. Fe-P and De-P were the main chemical forms of IP in core sediments. The profile variation of OP presented the most significant among the phosphorus forms. Whereas the concentrations of Ex-P, Fe-P, and Ca-P varied slightly with depth, indicating that the transformation of Ex-P, Fe-P, Ca-P, and OP could occur during sedimentary P burial. Moreover, the distribution of P species was influenced by many factors, including terrigenous input, biological processes, organic matter degradation and increasing human activities. High total organic carbon (TOC)/OP ratio occurred in the Jiaozhou Bay, ranging from 73 to 472 (average, 180 ± 81) in core sediments, which was caused by the increasing terrestrial organic matter. The ratio of TOC/Preactive ranged from 24 to 101 (average 46 ± 15) in core sediments (lower than the Redfield ratio), implying a surplus of sedimentary reactive P compared with TOC. Potential bioavailable P (BAP) accounted for about 28.2-60.8% (average, 47.1 ± 7.4%) of TP in core sediments, and presented an increasing trend since 1980s, which might be responsible for the shift of phytoplankton community composition during these decades.

  12. Subsoil erosion dominates the supply of fine sediment to rivers draining into Princess Charlotte Bay, Australia.

    Science.gov (United States)

    Olley, Jon; Brooks, Andrew; Spencer, John; Pietsch, Timothy; Borombovits, Daniel

    2013-10-01

    The Laura-Normanby River (catchment area: 24,350 km(2)), which drains into Princess Charlotte Bay, has been identified in previous studies as the third largest contributor of sediment to the Great Barrier Reef World Heritage Area. These catchment scale modelling studies also identified surface soil erosion as supplying >80% of the sediment. Here we use activity concentrations of the fallout radionuclides (137)Cs and (210)Pbex to test the hypothesis that surface soil erosion dominates the supply of fine (erosion being the dominant source of fine sediment in this catchment. The hypothesis that surface soil erosion dominates the supply of fine sediment to Princess Charlotte Bay is rejected. River sediment samples were collected using both time-integrated samplers and sediment drape deposits. We show that there is no detectable difference in (137)Cs and (210)Pbex activity concentrations between samples collected using these two methods. Two methods were also used to collect samples to characterise (137)Cs and (210)Pbex concentrations in sediment derived from surface soil erosion; sampling of surface-wash deposits and deployment of surface runoff traps that collected samples during rain events. While there was no difference in the (137)Cs activity concentrations for samples collected using these two methods, (210)Pbex activity concentrations were significantly higher in the samples collected using the runoff traps. The higher (210)Pbex concentrations are shown to be correlated with loss-on-ignition (r(2) = 0.79) and therefore are likely to be related to higher organic concentrations in the runoff trap samples. As a result of these differences we use a three end member mixing model (channel/gully, hillslope surface-wash and hillslope runoff traps) to determine the relative contribution from surface soil erosion. Probability distributions for (137)Cs and (210)Pbex concentrations were determined for each of the end members, with these distributions then used to estimate

  13. (129)I record of nuclear activities in marine sediment core from Jiaozhou Bay in China.

    Science.gov (United States)

    Fan, Yukun; Hou, Xiaolin; Zhou, Weijian; Liu, Guangshan

    2016-04-01

    Iodine-129 has been used as a powerful tool for environmental tracing of human nuclear activities. In this work, a sediment core collected from Jiaozhou Bay, the east coast of China, in 2002 was analyzed for (129)I to investigate the influence of human nuclear activities in this region. Significantly enhanced (129)I level was observed in upper 70 cm of the sediment core, with peak values in the layer corresponding to 1957, 1964, 1974, 1986, and after 1990. The sources of (129)I and corresponding transport processes in this region are discussed, including nuclear weapons testing at the Pacific Proving Grounds, global fallout from a large numbers of nuclear weapon tests in 1963, the climax of Chinese nuclear weapons testing in the early 1970s, the Chernobyl accident in 1986, and long-distance dispersion of European reprocessing derived (129)I. The very well (129)I records of different human nuclear activities in the sediment core illustrate the potential application of (129)I in constraining ages and sedimentation rates of the recent sediment. The releases of (129)I from the European nuclear fuel reprocessing plants at La Hague (France) and Sellafield (UK) were found to dominate the inventory of (129)I in the Chinese sediments after 1990, not only the directly atmospheric releases of these reprocessing plants, but also re-emission of marine discharged (129)I of these reprocessing plants in the highly contaminated European seas.

  14. [Effects of sediment dredging on benthos community structure and water quality in Zhushan Bay].

    Science.gov (United States)

    Liu, Guo-Feng; Zhang, Zhi-Yong; Liu, Hai-Qin; Zhong, Ji-Cheng; Yan, Shao-Hua; Fan, Cheng-Xin

    2010-11-01

    We surveyed the changes of macro-benthos community composition and nutrients concentration in water in Zhushan Bay after it had been dredged 6 months, which aimed to remove the polluted surface sediments. The results showed that the main benthos in the dredged and un-dredged sediments were Limodrilus hoffmeisteri, Pelopia and Bellamya aeruginosa; compared to the un-dredged sediments, the bio-diversity of dredged areas became lower. However, its biomass became higher than that in un-dredged areas. Concentration range changes of TN and TP in overlying water was 1.64-4.45 mg/L and 0.133-0.258 mg/L, respectively. The post-dredged sediments were still in a higher state of nutrients for the higher concentration nutrients in overlying water, macro-benthos were the species that lived in a serious polluted water environment. Using Shannon-Weaver, Simpson, and Goodnight benthic index to evaluate the results show that the dredged area is in the moderately polluted level, but un-dredged area is in the middle-heavily polluted level. According to the benthos fauna surveys and water quality monitoring results, the effective of sediment dredging could play its role only the strict control on the external pollution resources have been made and reduces the effects of polluted water on the sediments.

  15. Inferior adaptation of bay sediments in a eutrophic shallow lake to winter season for organic matter decomposition.

    Science.gov (United States)

    Song, Na; He, Yu-Hong; Jiang, He-Long

    2016-12-01

    Sediments in lake bays receive the greatest external pollutants mainly including terrestrial plants and river macrophyte detritus. This work investigated response and adaptation of bay sediments to organic matter (OM) decomposition under cold and hot seasons. After three month and incubated at 5 °C, it was found that the total organic carbon (TOC) removal efficiencies ranged from 15.4 to 13.1% in bay sediments to 22.6-25.7% in pelagic zone. These results determined that poorer OM decomposition occurred in the bay zone during the winter months compared to pelagic zone in a eutrophic shallow lake. High-throughput sequencing and network interactions revealed that the reactions were mainly due to the changing microbial community structure and species interaction at selected areas during different seasons. The bay zone communities are poorly adapted to utilizing the more recalcitrant carbon pool than the pelagic communities. Also, even though more taxa reside in bay communities, less co-occurrences interaction between taxa occurs, which mean that less inter taxa competition for the same resource. In consideration of our study, the potential harm, such as the terrestrialization process speeding up and water quality worsening will be happened, we need to exploit ways to enhance litter biodegradation in the bay zone in winter.

  16. Distribution of heavy metals and foraminiferal assemblages in sediments of Biscayne Bay, Florida, USA

    Science.gov (United States)

    Carnahan, E.A.; Hoare, A.M.; Hallock, P.; Lidz, B.H.; Reich, C.D.

    2008-01-01

    Heavy-metal pollution is an issue of concern in estuaries influenced by agriculture, urban, and harbor activities. Foraminiferal assemblages have been shown to be effective indicators of pollution. Sediment samples (n = 110) from Biscayne Bay were analyzed for heavy metals, foraminiferal assemblages, and grain-size distribution. Highest Cu, Zn, Cr, Hg, Pb, and Ni concentrations were found closest to Miami and near the mouths of several canals along the western margin of the bay. Few samples exceeded limits of possible biological effects as defined by previous studies. Ammonia and Cribroelphidium, two known stress-tolerant genera, correlated positively with Cu, Zn, Hg, and Ni (r ??? 0.43). Symbiont-bearing foraminifers, Archaias, Laevipeneroplis, and Androsina, correlated negatively with Cu, Zn, Hg, and Ni (r ??? -0.26).

  17. Metagenomic evidence for reciprocal particle exchange between the mainstem estuary and lateral bay sediments of the lower Columbia River

    Directory of Open Access Journals (Sweden)

    Mariya W Smith

    2015-10-01

    Full Text Available Lateral bays of the lower Columbia River estuary are areas of enhanced water retention that influence net ecosystem metabolism through activities of their diverse microbial communities. Metagenomic characterization of sediment microbiota from three disparate sites in two brackish lateral bays (Baker and Youngs produced approximately 100 Gbp of DNA sequence data analyzed subsequently for predicted SSU rRNA and peptide-coding genes. The metagenomes were dominated by Bacteria. A large component of Eukaryota was present in Youngs Bay samples, i.e. the inner bay sediment was enriched with the invasive New Zealand mudsnail, Potamopyrgus antipodarum, known for high ammonia production. The metagenome was also highly enriched with an archaeal ammonia oxidizer closely related to Nitrosoarchaeum limnia. Combined analysis of sequences and continuous, high-resolution time series of biogeochemical data from fixed and mobile platforms revealed the importance of large-scale reciprocal particle exchanges between the mainstem estuarine water column and lateral bay sediments. Deposition of marine diatom particles in sediments near Youngs Bay mouth was associated with a dramatic enrichment of Bacteroidetes (58% of total Bacteria and corresponding genes involved in phytoplankton polysaccharide degradation. The Baker Bay sediment metagenome contained abundant Archaea, including diverse methanogens, as well as functional genes for methylotrophy and taxonomic markers for syntrophic bacteria, suggesting that active methane cycling occurs at this location. Our previous work showed enrichments of similar anaerobic taxa in particulate matter of the mainstem estuarine water column. In total, our results identify the lateral bays as both sources and sinks of biogenic particles significantly impacting microbial community composition and biogeochemical activities in the estuary.

  18. Time trends of perfluorinated compounds from the sediment core of Tokyo Bay, Japan (1950s-2004)

    Energy Technology Data Exchange (ETDEWEB)

    Zushi, Yasuyuki; Tamada, Masafumi [Graduate School of Environment and Information Sciences, Yokohama National University, 79-7 Tokiwadai, Hodogaya, Yokohama 240-8501 (Japan); Kanai, Yutaka [Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba 305-8567 (Japan); Masunaga, Shigeki, E-mail: masunaga@ynu.ac.j [Graduate School of Environment and Information Sciences, Yokohama National University, 79-7 Tokiwadai, Hodogaya, Yokohama 240-8501 (Japan)

    2010-03-15

    Perfluorinated compounds (PFCs) were detected in sediment core samples collected in Tokyo Bay to reveal their time trends. The core sample deposited during 1950s-2004 was divided into two- to three-year intervals and the concentrations of 24 types of PFCs were determined. Perfluorooctane sulfonate (PFOS) decreased gradually from the early 1990s and its precursor decreased rapidly in the late 1990s, whereas perfluorooctanoic acid (PFOA) increased rapidly. The observed trends were regarded as a reflection of the shift from perfluorooctyl sulfonyl fluoride (PFOSF)-based products to telomer-based products after the phaseout of PFOSF-based products in 2001. The branched isomers of perfluoroundecanoic acid (PFUnDA) and perfluorotridecanoic acid (PFTrDA) were detected in the sample with its ratio of linear-isomer/branched-isomer concentrations decreasing. In this study, we revealed that the sediment core can serve as a tool for reconstructing the past pollution trend of PFCs and can provide interesting evidence concerning their environmental dynamics and time trend. - This study reports the time trends of the concentrations of 24 species of PFCs, including FTCA, FTUCA and FOSAA, in a sediment core of Tokyo Bay, Japan.

  19. Polycyclic aromatic hydrocarbons in surface sediment from Yangpu Bay, China: Distribution, sources and risk assessment.

    Science.gov (United States)

    Li, Ping; Diao, Xiaoping; Zhang, Yu; Xie, Yanli; Yang, Fei; Zhou, Hailong; Han, Qian; Wang, Fuqiang; Cheng, Huamin; Wang, Haihua

    2015-10-15

    The study investigated the occurrence of polycyclic aromatic hydrocarbons (PAHs) in the surface sediment from eleven sites in Yangpu Bay, China in December 2013 (winter) and July 2014 (summer). The 16 US EPA priority PAHs were found in the range of 1583.2-5701.7 ng/g dry weights with an average of 3134.7 ± 1241.3 ng/g in winter and ranged from 2161.8 to 4527.2 ng/g with an average of 3016.6 ± 748.0 ng/g in summer, respectively. The concentrations of the PAHs tended to be relatively high in comparison with other areas from the literatures. The identification using molecular indices analysis indicated that the PAHs originated mainly from pyrogenic and petrogenic sources in most of the sites. According to principle component analysis-multiple linear regression (PCA/MLR) for their source apportionment, the main sources of PAHs were vehicle emissions, petroleum products and biomass combustion. The risk assessment using international sediments quality guidelines and sediments quality criteria indicated that several PAHs, such as Nap, Flu, Phe, Ace, Acy and BghiP in most of the sites would potentially affect organisms in Yangpu Bay.

  20. Heavy metal pollution in tidal zones of Bohai Bay using the dated sediment cores

    Institute of Scientific and Technical Information of China (English)

    QIN Yan-wen; MENG Wei; ZHENG Bing-hui; SU Yi-bin

    2006-01-01

    Three sediment cores were collected in November 2003 from Dagu estuary to Qikou estuary. The main polluted heavy metals in the sediment of tidal zones for the Bohai Bay have been found by analyzing the relationship among the contents of heavy metals, the contents of geochemical elements (Fe, Al and Mn) and the size of grain. The dominating contaminative elements in tidal sediments of Bohai Bay are Pb, Zn and Cd. Their contents are higher than the corresponding upper limit of environmental background values and they have very faint correlation with the corresponding contents of geochemical elements and the size of grain, indicating the anthropogenic enrichment. Especially, the preliminary study on the pollution sources and the history of heavy metals in the Dagu estuary has been done using the dated results. The contamination by Zn and Cd also started in the middle 1950s, while the contamination by Pb appeared in the early 1940s. The pollution by Zn and Cd mainly originate from sewage discharge, while the pollution by Pb has many sources, like atmosphere deposition and industrial discharge.

  1. Hydrography and bottom boundary layer dynamics: Influence on inner shelf sediment mobility, Long Bay, North Carolina

    Science.gov (United States)

    Davis, L.A.; Leonard, L.A.; Snedden, G.A.

    2008-01-01

    This study examined the hydrography and bottom boundary-layer dynamics of two typical storm events affecting coastal North Carolina (NC); a hurricane and the passages of two small consecutive extratropical storms during November 2005. Two upward-looking 1200-kHz Acoustic Doppler Current Profilers (ADCP) were deployed on the inner shelf in northern Long Bay, NC at water depths of less than 15 m. Both instruments profiled the overlying water column in 0.35 in bins beginning at a height of 1.35 in above the bottom (mab). Simultaneous measurements of wind speed and direction, wave and current parameters, and acoustic backscatter were coupled with output from a bottom boundary layer (bbl) model to describe the hydrography and boundary layer conditions during each event. The bbl model also was used to quantify sediment transport in the boundary layer during each storm. Both study sites exhibited similar temporal variations in wave and current magnitude, however, wave heights during the November event were higher than waves associated with the hurricane. Near-bottom mean and subtidal currents, however, were of greater magnitude during the hurricane. Peak depth-integrated suspended sediment transport during the November event exceeded transport associated with the hurricane by 25-70%. Substantial spatial variations in sediment transport existed throughout both events. During both events, along-shelf sediment transport exceeded across-shelf transport and was related to the magnitude and direction of subtidal currents. Given the variations in sediment type across the bay, complex shoreline configuration, and local bathymetry, the sediment transport rates reported here are very site specific. However, the general hydrography associated with the two storms is representative of conditions across northern Long Bay. Since the beaches in the study area undergo frequent renourishment to counter the effects of beach erosion, the results of this study also are relevant to coastal

  2. Chronic sublethal effects of San Francisco Bay sediments on nereis (neanthes) arenaceodentata; effect of food ration on sediment toxicity. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Moore, D.W.; Dillon, T.M.

    1993-09-01

    This report is designed to address concerns regarding the effect of food ration on toxicity during chronic sublethal sediment bioassays. To this end, a contaminated San Francisco Bay sediment and a clean control sediment were evaluated in a chronic sublethal test under a series of different food rations, with the marine polychaete worm Nereis (Neanthes) arenaceodentata. Animals were exposed from early juvenile stage through the onset of gametogenesis. Treatments were 2.OX, 1.OX, 0.5X, and 0.25X where X is the recommended food ration for laboratory cultures. Test end points were survival, growth, and reproduction. The contaminated sediment was a composite of several cores taken to project depth (38 ft (11.6 m) below mean low water mark) from an area in Oakland Inner Harbor known to be contaminated with polycyclic aromatic hydrocarbons and metals. Comparisons were made with a clean control sediment. The control sediment is used in the laboratory cultures of N. arenaceodentata and was collected from Sequim, WA. Mean percent survival of Neanthes was high (>90 percent) in both the contaminated and control sediment across all food ration treatments. Individual wet weights were significantly reduced with decreasing food ration in both contaminated and control sediments. Significant differences in wet weight between sediment types were observed at the 1.OX, 0.5X, and 0.25X rations. Reproduction (fecundity and emergent juvenile (EJ) production) was also Chronic sublethal, Neanthes, Dredged material, San Francisco Bay, Food ration, Sediment.

  3. 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.

  4. Phosphorus sorption and buffering mechanisms in suspended sediments from the Yangtze Estuary and Hangzhou Bay, China

    Directory of Open Access Journals (Sweden)

    M. Li

    2013-05-01

    Full Text Available The adsorption isotherm and the mechanism of the buffering effect are important controls on phosphorus (P behaviors in estuaries and are important for estimating phosphate concentrations in aquatic environments. In this paper, we derive phosphate adsorption isotherms in order to investigate sediment adsorption and buffering capacity for phosphorus discharged from sewage outfalls in the Yangtze Estuary and Hangzhou Bay near Shanghai, China. Experiments were also carried out at different temperatures in order to explore the buffering effects for phosphate. The results show that P sorption in sediments with low fine particle fractions was best described using exponential equations. Some P interactions between water and sediment may be caused by the precipitation of CaHPO4 from Ca2+ and HPO42− when the phosphate concentration in the liquid phase is high. Results from the buffering experiments suggest that the Zero Equilibrium Phosphate Concentrations (EPC0 vary from 0.014 mg L−1 to 0.061 mg L−1, which are consistent with measured phosphate concentrations in water samples collected at the same time as sediment sampling. Values of EPC0 and linear sorption coefficients (K in sediments with high fine particle and organic matter contents are relatively high, which implies that they have high buffering capacity. Both EPC0 and K increase with increasing temperature, indicating a higher P buffering capacity at high temperatures.

  5. The distribution of inorganic phosphorus in modern sediments of the Bay of Biscay; La distribution du phosphore inorganique dans les sediments modernes du golfe de Gasgogne

    Energy Technology Data Exchange (ETDEWEB)

    Anschutz, P.; Hyacinthe, Ch.; Carbonel, P.; Jouanneau, J.M.; Jorissen, F. [Bordeaux-1 Univ., 33 - Talence (France). Dept. de Geologie et d`Oceanographie, UMR CNRS 5805

    1999-06-01

    The phosphorus geochemistry on the bay of Biscay margin shows that modern sediments represent a source of phosphate for overlying seawater. However, particulate phosphorus leached with an ascorbate solution and 1 N HCl remains constant in the sedimentary column which suggests that inorganic particulate phosphorus is trapped in the sediment. This is due to bioturbation, which carries iron oxides with high adsorption capacities for phosphate deep into the sediment, and also, to the precipitation of authigenic phosphate minerals in the anaerobic zone of the sediment. (authors) 17 refs.

  6. Sediment pathways and emergence of Himalayan source material in the Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Krishna, K.S.; Ismaiel, M.; Srinivas, K.; Gopala Rao, D.; Mishra, J.; Saha, D.

    to deep-water region and correlated the seis- mic startigraphy with the stratigraphic column in two in- dustrial deep-water bore holes (A and B; Figure 1). In the present study, we document the sediment dispersal pat- terns in time and space in the bay... isopach maps for different geological periods. The gridded data for all the horizons were brought to the GMT (Generic Mapping Tools) platform for preparation of time (two-way travel time; TWT) structure map of the western BoB. Isopach maps thus...

  7. Community structure of filamentous, sheath-building sulfur bacteria, Thioploca spp, off the coast of Chile

    DEFF Research Database (Denmark)

    Schulz, HN; Jørgensen, BB; Fossing, HA

    1996-01-01

    The filamentous sulfur bacteria Thioploca spp, produce dense bacterial mats in the shelf area off the coast of Chile and Peru. The mat consists of common sheaths, shared by many filaments, that reach 5 to 10 cm dean into the sediment, The structure of the Thioploca communities off the Bay...

  8. Community structure of filamentous, sheath-building sulfur bacteria, Thioploca spp, off the coast of Chile

    DEFF Research Database (Denmark)

    Schulz, HN; Jørgensen, BB; Fossing, HA

    1996-01-01

    The filamentous sulfur bacteria Thioploca spp, produce dense bacterial mats in the shelf area off the coast of Chile and Peru. The mat consists of common sheaths, shared by many filaments, that reach 5 to 10 cm dean into the sediment, The structure of the Thioploca communities off the Bay...

  9. Integrated assessment of mangrove sediments in the Camamu Bay (Bahia, Brazil).

    Science.gov (United States)

    Paixão, Joana F; de Oliveira, Olívia M C; Dominguez, José M L; Almeida, Edna dos Santos; Carvalho, Gilson Correia; Magalhães, Wagner F

    2011-03-01

    Camamu Bay, an Environmentally Protected Area, may be affected by the pressures of tourism and oil exploration in the adjacent continental platform. The current quality of the mangrove sediments was evaluated by porewater bioassays using embryos of Crassostrea rhizophorae and by an analysis of benthic macrofauna and its relationships with organic compounds, trace metals and bioavailability. Porewater toxicity varied from low to moderate in the majority of the samples, and polychaetes dominated the benthos. The Grande Island sampling station (Station 1) presented more sandy sediments, differentiated macrobenthic assemblages and the highest metal concentrations in relation to other stations and guideline values, and it was the only station that indicated a possible bioavailability of metals. The origin of the metals (mainly barium) is most likely associated with the barite ore deposits located in the Grande and Pequena islands. These results may be useful for future assessment of the impact of oil exploration in the coastal region. Copyright © 2010 Elsevier Inc. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    Luciane Alves Maranho

    2010-06-01

    Full Text Available Guanabara Bay is a marine-estuarine environment of high ecological and socio-economic importance, subject to a variety of environmental impacts. Sediment is the eventual repository for most substances introduced into water bodies and may, therefore, provide an integrated measure of the environmental quality, which can be assessed by many different approaches. In this project, the quality of sediments from Guanabara Bay was evaluated by the ecotoxicological approach: whole-sediment toxicity tests, using Tiburonella viscana, and porewater, elutriate and sediment-water interface chronic toxicity tests, using embryos of Lytechinus variegatus, were applied. Sediments were collected at 14 sampling stations, distributed across the bay. Chronic tests showed significant toxicity in most of the sediment samples. Sediments from stations 1, 2, 3, 6, 8, 10, 11, 12 and 15 showed acute toxicity as well. The results of the different tests were well correlated, and their integration showed that the sediments analyzed were considered unsuitable for aquatic life, resulting in the environmental degradation of Guanabara Bay. In this context, the control of pollution sources and multi-purpose management are required to improve the environmental quality.A Baía de Guanabara é um ambiente marinho-estuarino de grande relevância ecológica e sócio-econômica, e sujeita a uma ampla gama de impactos ambientais. O sedimento é o principal destino para a maioria das substâncias introduzidas nos corpos d'água, podendo fornecer uma medida integrada da qualidade ambiental, a qual pode ser avaliada por várias abordagens. Neste projeto, a qualidade de sedimentos da Baía de Guanabara foi por uma abordagem ecotoxicológica, por meio de testes de toxicidade aguda de sedimento integral, utilizando Tiburonella viscana, e testes de toxicidade crônica de água intersticial, elutriato e interface sedimento-água, utilizando embriões de Lytechinus variegatus. Os sedimentos foram

  11. Steroid markers to assess sewage and other sources of organic contaminants in surface sediments of Cienfuegos Bay, Cuba.

    Science.gov (United States)

    Tolosa, I; Mesa, M; Alonso-Hernandez, C M

    2014-09-15

    Analyses of faecal steroids in coastal sediments from Cienfuegos Bay Cuba indicate chronic sewage contamination at the main outfalls from the city, where concentrations of coprostanol up to 5400ngg(-)(1) (dry wt) were measured. In contrast, steroid concentrations and compositions from sites from the south part of the Bay are characteristic of uncontaminated sewage environments. The levels of coprostanol in the Cienfuegos sediments compares to the lower to mid-range of concentrations reported for coastal sediments on a world-wide basis, with sedimentary levels markedly below those previously reported for heavily impacted sites. This study delivers baseline data for further investigation of the effectiveness of the proposed sewerage plan promoted by the GEF project in Cienfuegos. Investigations on the correlations between faecal steroids and other organic contaminants confirmed that the major source of petroleum hydrocarbons within the bay was associated with the sewage effluents from the Cienfuegos city.

  12. Long-term changes in sediment and nutrient delivery from Conowingo Dam to Chesapeake Bay: Effects of reservoir sedimentation

    Science.gov (United States)

    Zhang, Qian; Hirsch, Robert M.; Ball, William P.

    2016-01-01

    Reduction of suspended sediment (SS), total phosphorus (TP), and total nitrogen is an important focus for Chesapeake Bay watershed management. The Susquehanna River, the bay’s largest tributary, has drawn attention because SS loads from behind Conowingo Dam (near the river’s mouth) have been rising dramatically. To better understand these changes, we evaluated histories of concentration and loading (1986–2013) using data from sites above and below Conowingo Reservoir. First, observed concentration-discharge relationships show that SS and TP concentrations at the reservoir inlet have declined under most discharges in recent decades, but without corresponding declines at the outlet, implying recently diminished reservoir trapping. Second, best estimates of mass balance suggest decreasing net deposition of SS and TP in recent decades over a wide range of discharges, with cumulative mass generally dominated by the 75∼99.5th percentile of daily Conowingo discharges. Finally, stationary models that better accommodate effects of riverflow variability also support the conclusion of diminished trapping of SS and TP under a range of discharges that includes those well below the literature-reported scour threshold. Overall, these findings suggest that decreased net deposition of SS and TP has occurred at subscour levels of discharge, which has significant implications for the Chesapeake Bay ecosystem.

  13. Persistence and growth of faecal culturable bacterial indicators in water column and sediments of Vidy Bay, Lake Geneva, Switzerland

    Institute of Scientific and Technical Information of China (English)

    POTE John; HALLER Laurence; KOTTELAT Régis; SASTRE Vincent; ARPAGAUS Philippe; WILDI Walter

    2009-01-01

    The aims of this study was to investigate the persistence and the growth of culturable bacterial indicators (CBI) including total coliforms (TC) and faecal coliforms represented by E. coli, enterococcus (ENT), and aerobic mesophilic bacteria (AMB) in the surface sediments and the water column of the Bay of Vidy (Lake Geneva, City of Lausanne, Switzerland). The study was carried out for 60 d using microcosms containing Sewage Treatment Plant (STP) effluent water and non-sterile water without CBI, as well as contaminated and non-contaminated sediments. The effects of water temperature and of organic matter associated with sediments on the survival of CBI in the sediments and the water column were observed. The number of CBI colonies in the contaminated sediments of Vidy Bay and in the STP effluent water was almost identical in the order of 105--107, 104--106, 103--105, and 104--107 CFU/100 g sediment or /100 mL water for TC, E. coli, ENT, and AMB respectively. A degradation of CBI was observed in the sediments where organic mater content was low and in the water column at a temperature of 10℃ after 5 d of experimentation. In addition, a growth of CBI was observed in the sediment which is rich in organic matter at a temperature of 20℃. The results of this study indicate: (1) the higher concentrations of the CBI observed in different points in the water column of Vidy Bay may not be explained only by the recent contribution of the three potential sources of the Bay contamination including STP and the Chamberonne and Flon Rivers, but also by the persistence, removal from sediment and multiplication of CBI in the sediment and water column; (2) the sediment of Vidy Bay constitute a reservoir of CBI and can even support their growth. (3) the CBI not only survive in sediments, but also can be remobilized and increased in the water column, therefore it become a permanent microbiological pollution in Vidy Bay.

  14. Extraordinary sediment delivery and rapid geomorphic response following the 2008–2009 eruption of Chaitén Volcano, Chile

    Science.gov (United States)

    Major, Jon J.; Bertin, Daniel; Pierson, Thomas C.; Amigo, Alvaro; Iroume, Andres; Ulloa, Hector; Castro, Jonathan M.

    2016-01-01

    The 10 day explosive phase of the 2008–2009 eruption of Chaitén volcano, Chile, draped adjacent watersheds with a few cm to >1 m of tephra. Subsequent lava-dome collapses generated pyroclastic flows that delivered additional sediment. During the waning phase of explosive activity, modest rainfall triggered an extraordinary sediment flush which swiftly aggraded multiple channels by many meters. Ten kilometer from the volcano, Chaitén River channel aggraded 7 m and the river avulsed through a coastal town. That aggradation and delta growth below the abandoned and avulsed channels allow estimates of postdisturbance traction-load transport rate. On the basis of preeruption bathymetry and remotely sensed measurements of delta-surface growth, we derived a time series of delta volume. The initial flush from 11 to 14 May 2008 deposited 0.5–1.5 × 106 m3 of sediment at the mouth of Chaitén River. By 26 May, after channel avulsion, a second delta amassed about 2 × 106 m3 of sediment; by late 2011 it amassed about 11 × 106 m3. Accumulated sediment consists of low-density vesicular pumice and lithic rhyolite sand. Rates of channel aggradation and delta growth, channel width, and an assumed deposit bulk density of 1100–1500 kg m−3 indicate mean traction-load transport rate just before and shortly after avulsion (∼14–15 May) was very high, possibly as great as several tens of kg s−1 m−1. From October 2008 to December 2011, mean traction-load transport rate declined from about 7 to 0.4 kg−1 m−1. Despite extraordinary sediment delivery, disturbed channels recovered rapidly (a few years).

  15. Extraordinary sediment delivery and rapid geomorphic response following the 2008-2009 eruption of Chaitén Volcano, Chile

    Science.gov (United States)

    Major, Jon J.; Bertin, Daniel; Pierson, Thomas C.; Amigo, Álvaro; Iroumé, Andrés.; Ulloa, Héctor; Castro, Jonathan

    2016-07-01

    The 10 day explosive phase of the 2008-2009 eruption of Chaitén volcano, Chile, draped adjacent watersheds with a few cm to >1 m of tephra. Subsequent lava-dome collapses generated pyroclastic flows that delivered additional sediment. During the waning phase of explosive activity, modest rainfall triggered an extraordinary sediment flush which swiftly aggraded multiple channels by many meters. Ten kilometer from the volcano, Chaitén River channel aggraded 7 m and the river avulsed through a coastal town. That aggradation and delta growth below the abandoned and avulsed channels allow estimates of postdisturbance traction-load transport rate. On the basis of preeruption bathymetry and remotely sensed measurements of delta-surface growth, we derived a time series of delta volume. The initial flush from 11 to 14 May 2008 deposited 0.5-1.5 × 106 m3 of sediment at the mouth of Chaitén River. By 26 May, after channel avulsion, a second delta amassed about 2 × 106 m3 of sediment; by late 2011 it amassed about 11 × 106 m3. Accumulated sediment consists of low-density vesicular pumice and lithic rhyolite sand. Rates of channel aggradation and delta growth, channel width, and an assumed deposit bulk density of 1100-1500 kg m-3 indicate mean traction-load transport rate just before and shortly after avulsion (˜14-15 May) was very high, possibly as great as several tens of kg s-1 m-1. From October 2008 to December 2011, mean traction-load transport rate declined from about 7 to 0.4 kg-1 m-1. Despite extraordinary sediment delivery, disturbed channels recovered rapidly (a few years).

  16. Phylogenetic analysis of Beggiatoa spp. from organic rich sediment of Tokyo Bay, Japan.

    Science.gov (United States)

    Kojima, Hisaya; Fukui, Manabu

    2003-07-01

    Nitrate-accumulating filamentous bacteria from organic rich sediment of Tokyo Bay, morphologically similar to Beggiatoa species, were phylogenetically analyzed. From several sites in Tokyo Bay, Beggiatoa-like bacteria were collected. Each sample contained narrower or wider type (10 and 30 microns, respectively) of trichomes. With the nested PCR using specific primers for Beggiatoa, fragments of 16S rRNA gene were amplified and then subjected to denaturing gradient gel electrophoresis (DGGE) analysis. Sequencing and the following phylogenetic analysis indicated that they are related to large Beggiatoa species. The wider type was related to uncultured Beggiatoa clones of other geographical localities and distinct from the narrower type in Tokyo Bay. Among the narrower types, a sample from a tidal flat was genetically distinct from the sample from sites of 10 and 20 m water depth. These narrower types form a new branch in Beggiatoa/Thioploca cluster. The result of phylogenetic analysis was in accordance with the previous studies that indicate possession of nitrate-accumulation capability is congruent with phylogeny based on 16S rRNA sequences.

  17. Polychlorinated biphenyls in sediments and fish species from the Murchison Bay of Lake Victoria, Uganda.

    Science.gov (United States)

    Ssebugere, Patrick; Sillanpää, Mika; Wang, Pu; Li, Yingming; Kiremire, Bernard T; Kasozi, Gabriel N; Zhu, Chaofei; Ren, Daiwei; Zhu, Nali; Zhang, Haidong; Shang, Hongtao; Zhang, Qinghua; Jiang, Guibin

    2014-06-01

    Polychlorinated biphenyls (PCBs) were determined in sediments and two fish species collected from the Murchison Bay in Lake Victoria, using high resolution gas chromatography coupled to a high resolution mass spectrometer. Total PCB concentrations (Σ18PCBs) varied widely with mean values ranging from 777 to 4325pg g(-1) dry weight (dw) for sediments and 80 to 779pg g(-1) wet weight (ww) for fish. The PCB levels in the sediments were significantly higher at the station closest to Nakivubo channel, presumably due to effluents discharged by the channel, which may contain domestically produced commercial PCB mixtures. For fish, the concentrations in Nile perch (Lates niloticus) were significantly greater than those in Nile tilapia (Oreochromis niloticus) at all study stations, possibly due to dietary differences among species. World Health Organization-toxic equivalents (WHO2005-TEQs) for the dioxin-like PCBs were 0.04-0.64pg g(-1) dw and 0.01-0.39pg g(-1) ww for sediments and fish, respectively. The non-ortho PCBs exhibited the highest contribution to the Σ12TEQs (>75%) compared to the mono-ortho PCBs in both fish species. The TEQs in the present study were lower than many reported worldwide in literature for fish and were within the permissible level recommended by the European Commission, implying that the fish did not pose health hazards related to PCBs to the consumers.

  18. Occurrence and distribution of polycyclic aromatic hydrocarbons in surface sediments of San Diego Bay marinas.

    Science.gov (United States)

    Neira, Carlos; Cossaboon, Jennifer; Mendoza, Guillermo; Hoh, Eunha; Levin, Lisa A

    2017-01-15

    Polycyclic aromatic hydrocarbons (PAHs) have garnered much attention due to their bioaccumulation, carcinogenic properties, and persistence in the environment. Investigation of the spatial distribution, composition, and sources of PAHs in sediments of three recreational marinas in San Diego Bay, California revealed significant differences among marinas, with concentrations in one site exceeding 16,000ngg(-1). 'Hotspots' of PAH concentration suggest an association with stormwater outfalls draining into the basins. High-molecular weight PAHs (4-6 rings) were dominant (>86%); the average percentage of potentially carcinogenic PAHs was high in all sites (61.4-70%) but ecotoxicological risks varied among marinas. Highly toxic benzo(a)pyrene (BaP) was the main contributor (>90%) to the total toxic equivalent quantity (TEQ) in marinas. PAHs in San Diego Bay marina sediments appear to be derived largely from pyrogenic sources, potentially from combustion products that reach the basins by aerial deposition and stormwater drainage from nearby streets and parking lots. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Temporal variation of persistent organic pollutant (POP) residue concentrations in sediments from the bay of Chetumal, Mexico.

    Science.gov (United States)

    Noreña-Barroso, E; Gold-Bouchot, G; Ceja-Moreno, V

    2007-08-01

    Bay of Chetumal is a transboundary priority area for the Mesoamerican Barrier Reef Systems project, which has been studied because it is the receiving body of pollutants from a large agricultural area and the city of Chetumal. Levels of persistent organic pollutants in sediments from the Bay were assessed a few years after a mass mortality event of Mayan catfish (Ariopsis assimilis) occurred in 1996. Recent sediments were collected in the rainy season (1999) and dry season (2000); results show concentrations in general lower than those reported after the fish kill, and a change of chemical profiles in chemical pollution.

  20. Combining contamination indexes, sediment quality guidelines and multivariate data analysis for metal pollution assessment in marine sediments of Cienfuegos Bay, Cuba.

    Science.gov (United States)

    Peña-Icart, Mirella; Pereira-Filho, Edenir Rodrigues; Lopes Fialho, Lucimar; Nóbrega, Joaquim A; Alonso-Hernández, Carlos; Bolaños-Alvarez, Yoelvis; Pomares-Alfonso, Mario S

    2017-02-01

    The purpose of the present work was to combine several tools for assessing metal pollution in marine sediments from Cienfuegos Bay. Fourteen surface sediments collected in 2013 were evaluated. Concentrations of As, Cu, Ni, Zn and V decreased respect to those previous reported. The metal contamination was spatially distributed in the north and south parts of the bay. According to the contamination factor (CF) enrichment factor (EF) and index of geoaccumulation (Igeo), Cd and Cu were classified in that order as the most contaminated elements in most sediment. Comparison of the total metal concentrations with the threshold (TELs) and probable (PELs) effect levels in sediment quality guidelines suggested a more worrisome situation for Cu, of which concentrations were occasional associated with adverse biological effects in thirteen sediments, followed by Ni in nine sediments; while adverse effects were rarely associated with Cd. Probably, Cu could be considered as the most dangerous in the whole bay because it was classified in the high contamination levels by all indexes and, simultaneously, associated to occasional adverse effects in most samples. Despite the bioavailability was partially evaluated with the HCl method, the low extraction of Ni (<3% in all samples) and Cu (<55%, except sample 3) and the relative high extraction of Cd (50% or more, except sample 14) could be considered as an attenuating (Ni and Cu) or increasing (Cd) factor in the risk assessment of those element. Copyright © 2016. Published by Elsevier Ltd.

  1. An evaluation of temporal changes in sediment accumulation and impacts on carbon burial in Mobile Bay, Alabama, USA

    Science.gov (United States)

    Smith, Christopher G.; Osterman, Lisa E.

    2014-01-01

    The estuarine environment can serve as either a source or sink of carbon relative to the coastal ocean carbon budget. A variety of time-dependent processes such as sedimentation, carbon supply, and productivity dictate how estuarine systems operate, and Mobile Bay is a system that has experienced both natural and anthropogenic perturbations that influenced depositional processes and carbon cycling. Sediments from eight box cores provide a record of change in bulk sediment accumulation and carbon burial over the past 110 years. Accumulation rates in the central part of the basin (0.09 g cm−2) were 60–80 % less than those observed at the head (0.361 g cm−2) and mouth (0.564 g cm−2) of the bay. Sediment accumulation in the central bay decreased during the past 90 years in response to both anthropogenic (causeway construction) and natural (tropical cyclones) perturbations. Sediment accumulation inevitably increased the residence time of organic carbon in the oxic zone, as observed in modeled remineralization rates, and reduced the overall carbon burial. Such observations highlight the critical balance among sediment accumulation, carbon remineralization, and carbon burial in dynamic coastal environments. Time-series analysis based solely on short-term observation would not capture the long-term effects of changes in sedimentation on carbon cycling. Identifying these relationships over longer timescales (multi-annual to decadal) will provide a far better evaluation of coastal ocean carbon budgets.

  2. Concentrations of heavy metals in sediment and organisms during a harmful algal bloom (HAB) at Kun Kaak Bay, Sonora, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Hernandez, Jaqueline [Centro de investigacion en Alimentacion y Desarrollo AC (CIAD) Guaymas Unit, Carretera al Varadero Nal. Km 6.6, Apdo. Postal 284, CP 85480 Guaymas, Sonora (Mexico)]. E-mail: jaqueline@cascabel.ciad.mx; Garcia-Rico, Leticia [Centro de investigacion en Alimentacion y Desarrollo AC (CIAD), Carretera a la Victoria Km 0.6, Apdo. Postal 1735, CP 83000 Hermosillo, Sonora (Mexico)]. E-mail: lgarciar@cascabel.ciad.mx; Jara-Marini, Martin E. [Centro de investigacion en Alimentacion y Desarrollo AC (CIAD), Carretera a la Victoria Km 0.6, Apdo. Postal 1735, CP 83000 Hermosillo, Sonora (Mexico)]. E-mail: mjara@cascabel.ciad.mx; Barraza-Guardado, Ramon [Departamento de Investigaciones Cientificas y Tecnologicas de la Universidad de Sonora (DICTUS), Rosales y Ninos Heroes s/n Col. Centro, CP 83000 Hermosillo, Sonora (Mexico)]. E-mail: rbarraza@rtn.uson.mx; Hudson Weaver, Amy [Comunidad y Biodiversidad AC - COBI, Terminacion Bahia de Bacochibampo s/m, Fraccionamiento Lomas de Cortes, CP 85450 Guaymas, Sonora (Mexico)]. E-mail: ahw@cobi.org.mx

    2005-07-01

    In early April 2003, fishermen from Kino Bay Sonora alerted us about a massive die-off of fish and mollusks occurring at Kun Kaak Bay. Phytoplankton samples taken on 17 May 2003 reported the presence of a harmful algal bloom composed of Chatonella marina, Chatonella cf. ovata, Gymnodinium catenatum and Gymnodinium sanguineum. On 22 of May, we collected samples of water, sediment and organisms at the affected area. Physicochemical parameters and nutrients were measured in water samples from different depths. Sediment and benthic organisms were analyzed for Cd, Cu, Zn, Pb and Hg. We found concentrations of heavy metals higher than background levels for this area. Cadmium and Lead concentrations in sediment from the HAB area were up to 6x greater than background levels and Cd in mollusks was 8x greater than regulations allow. A relationship between elevated Cd and Pb concentrations in sediment and the survival of toxic dinoflagellates is suspected.

  3. Osseous skeletal material and fish scales in marine sediments under the oxygen minimum zone off northern and central Chile

    Science.gov (United States)

    Milessi, Andrés C.; Sellanes, Javier; Gallardo, Víctor A.; Lange, Carina B.

    2005-08-01

    The significance of whale falls for the study of the biogeography, evolution and biodiversity of deep-sea biota has been recently recognized by international programs since large carcasses are known to give rise to biogenic chemosynthetic ecosystems. However, the plain accumulation of smaller bone material in the shallower settings of the continental shelf and upper slope under the hypoxic conditions of the Oxygen Minimum Zone (OMZ), has received much less attention. Here we describe new findings of skeletal material and fish scales in marine sediments under the OMZ off northern and central Chile which, combined with previous reports for the study area, lead us to suggest the existence of a band in the benthos of accumulation of bones and scales extending at least twenty degrees in latitude (18-38° S). Future studies should focus on the characterization of biotic communities living upon these resources in order to elucidate their peculiarities and importance in the Eastern South Pacific.

  4. Distribution and sources of hydrocarbons in surface sediments of Gemlik Bay (Marmara Sea, Turkey).

    Science.gov (United States)

    Unlü, Selma; Alpar, Bedri

    2006-07-01

    Seabottom sediments from Gemlik Bay, one of the most polluted spots in SW Marmara Sea, were analyzed for parent polycyclic aromatic hydrocarbons (PAHs) using gas chromatography-mass spectrometry. The concentration of 14 PAH compounds in sediment samples collected from 61 locations are distributed in a broad spectrum from low to very high concentration levels (50.8-13482 ng g-1). No significant correlation was found between summation operatorPAHs and organic carbon content while summation operatorPAHs increase slightly with silt/clay ratio. Therefore the distribution and concentrations of PAHs would be determined more by direct input, rather than by the type of sediment found locally. The most polluted areas are distributed nearshore eastern (Gemlik) and southern (Kursunlu, Mudanya and Trilye) coasts which are mainly influenced by rapid ecotourism development, direct discharges from rivers, surface run-off and drainage from port areas, domestic and industrial effluent discharges through outfalls and various contaminants from ships. Special PAH compound ratios, such as Phe/Anth, Flu/Py, B[a]A/Chry; LMWPAH/HMWPAH; Per/; Per/summation operatorPAH; Per/summation operator(penta-aromatics) and Flu/(Py+Flu), were calculated to evaluate different hydrocarbon origins and their relative importance. Pyrolytic activity is dominant along the highly-populated eastern and southern coasts. Meanwhile, petrogenic activity mixed with pyrolytic activity is a matter of fact in front of the main industrial-tourism ports and anchoring areas as well. Higher concentration of perylene are distributed along the mostly polluted eastern and southern coastal areas, however, the concentrations of perylene relative to the penta-aromatic isomers are dominant especially in the northern and deepest sectors of the bay, indicating diagenetic origin for the presence of perylene.

  5. Carbon sources supporting benthic mineralization in mangrove and adjacent seagrass sediments (Gazi Bay, Kenya

    Directory of Open Access Journals (Sweden)

    S. Bouillon

    2004-01-01

    Full Text Available The origin of carbon substrates used by in situ sedimentary bacterial communities was investigated in an intertidal mangrove ecosystem and in adjacent seagrass beds in Gazi bay (Kenya by δ13C analysis of bacteria-specific PLFA (phospholipid fatty acids and bulk organic carbon. Export of mangrove-derived organic matter to the adjacent seagrass-covered bay was evident from sedimentary total organic carbon (TOC and δ13CTOC data. PLFA δ13C data indicate that the substrate used by bacterial communities varied strongly and that exported mangrove carbon was a significant source for bacteria in the adjacent seagrass beds. Within the intertidal mangrove forest, bacterial PLFA at the surface layer (0-1cm typically showed more enriched δ13C values than deeper (up to 10cm sediment layers, suggesting a contribution from microphytobenthos and/or inwelled seagrass material. Under the simplifying assumption that seagrasses and mangroves are the dominant potential end-members, the estimated contribution of mangrove-derived carbon to benthic mineralization in the seagrass beds (16-74% corresponds fairly well to the estimated contribution of mangrove C to the sedimentary organic matter pool (21-71% across different seagrass sites. Based on the results of this study and a compilation of literature data, we suggest that trapping of allochtonous C is a common feature in seagrass beds and often represents a significant source of C for sediment bacteria - both in cases where seagrass C dominates the sediment TOC pool and in cases where external inputs are significant. Hence, it is likely that data on community respiration rates systematically overestimate the role of in situ mineralization as a fate of seagrass production.

  6. Geochemical fine-sediment tracers in San Francisco Bay and its outer coast: the role of local watersheds

    Science.gov (United States)

    Takesue, R. K.; Barnard, P. L.

    2012-12-01

    Sediment enters San Francisco Bay (SFB) through the Sacramento-San Joaquin River Delta, the Golden Gate, and local watersheds. Inputs from local watersheds have become increasingly important since the 1940s when large-scale impoundments began upstream of the Delta. The goals of this study are to determine whether fine sediment from local watersheds have distinct geochemical signatures, and if these can be used to determine whether locally-derived sediment accumulates in SFB. Retention of fine sediment is essential if accretion of shallow and intertidal habitats is to keep pace with sea level rise. Total contents of chromium (Cr), lanthanum (La), thorium (Th), zirconium (Zr), rare earth elements (REE), and twenty five other elements were determined by ICP-MS in the fine or "mud" fraction (<63 μm) of river, tributary, bay, and outer coast bed sediment. SFB and outer coast sediment was collected in January 2012 after a 5-day storm. River and tributary sediment was collected between 2010-2012. REE contents were normalized to a shale composite (NASC). In comparison to granitic material from the Sierra Nevada, local watersheds contain ultramafic Franciscan rocks in the Coast Range, volcanic deposits near Napa and Sonoma, and ancient marine sedimentary rocks. Fine sediment from the Sacramento River was enriched in heavy REE (HREENASC) and Cr, while that from the San Joaquin River was enriched in light REE (LREENASC) and Th. Petaluma River and Sonoma Creek fine sediments were distinguished by middle REE (MREENASC) enrichments and low Cr contents consistent with felsic volcanic rocks. In contrast, fine sediments in Napa River and Wildcat Creek had relatively flat REENASC patterns and intermediate to high Cr contents that suggest a Franciscan influence. The same was true for fine sediment in Marin creeks (Arroyo del Presidio and Corte Madera) and two South Bay tributaries (Guadelupe River and San Francisquito Creek). San Francisquito Creek fine sediment was uniquely

  7. Relative Contribution of Endocrine-disrupting Chemicals to the Estrogenic Potency of Marine Sediments of Osaka Bay, Japan

    OpenAIRE

    KOYAMA, Jiro; KITOH, Asami; NAKAI, Makoto; KOHNO, Kumiko; Tanaka, Hiroyuki; Uno, Seiichi; コヤマ, ジロウ; キトウ, アサミ; ナカイ, マコト; コウノ, クミコ; タナカ, ヒロユキ; ウノ, セイイチ; 小山, 次朗; 中井, 誠; 河野, 久美子

    2013-01-01

    Although concentrations of endocrine-disrupting chemicals (EDCs) in seawaters of Japan are relatively low, vitellogenin and ovotestis inductions are still being observed in some males of mullet and flounder collected in coastal areas. These fish species are benthic and could be affected by EDCs in marine sediments. Therefore, the concentrations of EDCs in marine sediments of Osaka Bay were determined by LC-MS/MS. In addition, the estrogen receptor binding potencies as estrogenic potencies of ...

  8. Diatoms and aquatic palynomorphs in surface sediments of the White Sea bays as indicators of sedimentation in marginal filters of rivers

    Science.gov (United States)

    Polyakova, Ye. I.; Novichkova, Ye. A.; Lisitzin, A. P.; Shevchenko, V. P.; Kravchishina, M. D.

    2016-03-01

    Diatom algae, aquatic palynomorphs, and the grain-size of surface sediments from bays of the White Sea were investigated in a program dedicated to the study of marginal filters (MF) in the Severnaya Dvina, Onega, and Kem rivers. Three microalgal assemblages are established in surface sediments, which replace each other successively with distance from river mouths and are characterized by a gradual decrease in a share of freshwater species of diatoms and Chlorophyceae algae, significantly varying concentrations of marine diatoms and dinocysts due to changes in water salinity, grain-size composition of sediments, quantitative distribution of suspended particulate matter (SPM), and water productivity at different marginal filter stages.

  9. Diversity and distribution of bacterial community in the coastal sediments of Bohai Bay, China

    Institute of Scientific and Technical Information of China (English)

    WANG Liping; ZHENG Binghui; LEI Kun

    2015-01-01

    In order to understand the diversity and distribution of the bacterial community in the coastal sediment of the Bohai Bay, China, high-throughput barcoded pyrosequencing of the 16S rRNA gene was used. Metagenomic DNA was extracted from the sediment samples, and was sequenced using a 454 GS FLX Titanium system. At 97%similarity, the sequences were assigned to 22 884 operational taxonomic units (OTUs) which belonged to 41 phyla, 84 classes, 268 genera and 789 species. At the different taxonomic levels, both the dominants and their distribution varied significantly among the six coastal sediments. Proteobacteria was the first dominant phylum across all the six coastal sediments, representing 57.52%, 60.66%, 45.10%, 60.92%, 56.63% and 56.59%, respectively. Bacteroidetes was the second dominant phylum at Stas S1, S2 and S4, while Chloroflexi was the second dominant phylum at Stas S3, S5 and S6. At class level,γ-Proteobacteria was the first dominant class at Stas S1, S2, S4 and S6, whileδ-Proteobacteria became the first dominant class at Stas S3 and S5. In addition, a large proportion of unclassified representatives have distributed at the different taxonomic levels. Canonical correspondence analysis (CCA) results indicated that the sediment texture, water depth (D), dissolved oxygen (DO), total nitrogen (TN) and nine EPA priority control polycyclic aromatic hydrocarbons (PAHs) including naphthalene, acenaphthylene, acenaphthene, fluorine, phenanthrene, fluoranthene, pyrene, benzo[a]anthracene and indeno[1,2,3-cd]pyrene were the important factors in regulating the bacterial community composition. Those results are very important to further understand the roles of bacterial community in the coastal biogeochemical cycles.

  10. Relation of lead exposure to sediment ingestion in mute swans on the Chesapeake Bay, USA

    Science.gov (United States)

    Beyer, W.N.; Day, D.; Morton, Alexandra; Pachepsky, Y.

    1998-01-01

    Forty-two mute swans (Cygnus olor ) were collected from unpolluted portions of central Chesapeake Bay in spring 1995. Their intestinal digesta were analyzed for 13 metals (Al, B, Ba, Cd, Cu, Fe, Mg, Mn, Ni, Pb, Sr, V, Zn) and for acid-insoluble ash, a marker of sediment. Because metal concentrations in digesta depend on recent exposure, they are appropriate for evaluating local contamination. Swan livers and sediment samples also were analyzed for the same metals. Group method of data handling demonstrated that the digesta Al was the best predictor of digesta Pb, and that adding concentrations of other metals as predictors did not improve the accuracy of the estimates of Pb concentrations from Al concentrations. The r2 of the equation relating the log of digesta Pb to the log of digesta Al was 0.86, whereas the r2 of the equation relating the log of digesta Pb to the log of digesta acid-insoluble ash was 0.50. Sediment ingestion was critical in determining exposure to Pb, as well as to some of the other metals, and should be considered in ecotoxicological risk assessments of waterfowl. The mean of 7.4% acid-insoluble ash in the digesta corresponded to an estimated 3.2% sediment in the diet. The Pb concentrations in the digesta were 2-3 times the concentration that would have been predicted from sediment Pb concentrations; presumably the swans had ingested clays high in Pb that had settled on the vegetation. The swans were not thought to have been exposed to high Cu concentrations but they had hepatic Cu concentrations that would be considered very high if found in other species.

  11. Controls on subsurface methane fluxes and shallow gas formation in Baltic Sea sediment (Aarhus Bay, Denmark)

    Science.gov (United States)

    Flury, Sabine; Røy, Hans; Dale, Andrew W.; Fossing, Henrik; Tóth, Zsuzsanna; Spiess, Volkhard; Jensen, Jørn Bo; Jørgensen, Bo Barker

    2016-09-01

    Shallow gas accumulates in coastal marine sediments when the burial rate of reactive organic matter beneath the sulfate zone is sufficiently high and the methanogenic zone is sufficiently deep. We investigated the controls on methane production and free methane gas accumulation along a 400 m seismo-acoustic transect across a sharp transition from gas-free into gas-bearing sediment in Aarhus Bay (Denmark). Twelve gravity cores were taken, in which the pore water was analyzed for inorganic solutes while rates of organic carbon mineralization were measured experimentally by 35SO42- radiotracer method. The thickness of organic-rich Holocene mud increased from 5 to 10 m along the transect concomitant with a shallowing of the depth of the sulfate-methane transition from >4 m to 2.5 m. In spite of drastic differences in the distribution of methane and sulfate in the sediment along the transect, there were only small differences in total mineralization, and methanogenesis was only equivalent to about 1% of sulfate reduction. Shallow gas appeared where the mud thickness exceeded 8-9 m. Rates of methanogenesis increased along the transect as did the upward diffusive flux of methane. Interestingly, the increase in the sedimentation rate and Holocene mud thickness had only a modest direct effect on methanogenesis rates in deep sediments. This increase in methane flux, however, triggered a shallowing of the sulfate-methane transition which resulted in a large increase in methanogenesis at the top of the methanogenic zone. Thus, our results demonstrate a positive feedback mechanism that causes a strong enhancement of methanogenesis and explains the apparently abrupt appearance of gas when a threshold thickness of organic-rich mud is exceeded.

  12. Sedimentation Response to Holocene Landscape Disturbance on the Poverty Bay Continental Margin, East Coast New Zealand

    Science.gov (United States)

    Orpin, A. R.; Carter, L.; Alexander, C. R.; Kuehl, S. A.

    2004-12-01

    Since human settlement, dramatic landscape changes have occurred on the Raukumara Peninsula, East Coast North Island of New Zealand. In particular, European destruction of native forests for pasture caused accelerated erosion of the mudstone and sandstone dominated hinterland. Sediment eroded from the Raukumara Ranges is primarily carried by three small-catchment river systems, which collectively deliver approximately 70 Mt/y of suspended sediment, representing about 0.3% of total global input to the ocean. Today, the Waipaoa River delivers 15 Mt/y of mud to coastal Poverty Bay, accumulating in an actively subsiding mid-shelf basin and outer shelf lobe. The shelf is bordered along its seaward edge by two emergent ridges, but a significant component of hemipelagic sediment leaks through the 13 km-wide Poverty Gap between the ridges, and is deposited on the slope in a large structural indentation that is heavily incised by the Poverty submarine canyon system. Using Holocene tephrochronology, and accepting near-full capture of Holocene riverine sediment on the shelf and slope, accumulation rates indicate that the modern (post-colonisation) sediment input from the Waipaoa River is probably an order of magnitude higher than the average for the Holocene. Previous studies suggest that a five-times increase in accumulation rates by the early 1900's on the shelf is contemporaneous with deforestation. Modern sediment mass accumulation rates determined from excess 210Pb profiles suggest that shelf sedimentation increases seaward, reaching a maximum of 0.9 cm/y on the outer shelf, with no net accumulation apparent on the inner-middle shelf. In general, accumulation rates are an order of magnitude lower on the slope, around 0.1 cm/y, decreasing slightly down-slope. Palynological data show a succession of destruction of native forests by burning, extensive land clearance for pasture, and the establishment of exotic forests. These markers date the arrival of Polynesian settlers

  13. Seasonal and spatial characteristics of seawater and sediment at Youngil Bay, southeast coast of Korea.

    Science.gov (United States)

    Lee, Mikyung; Bae, Wookeun; Chung, Jinwook; Jung, Hoi-Soo; Shim, Hojae

    2008-01-01

    The seasonal geochemical characteristics of the seawater and sediments and the major factors causing heavy metal contamination were investigated at the Youngil bay and the Hyungsan river estuary in the Southeast Coast of Korea, where a world-scale steel-industry complex (Pohang iron and steel industrial complex, POSCO) is located. The seasonal and spatial distribution characteristics of temperature, dissolved oxygen (DO), pH, and nutrients of the seawater were studied at 45 fixed stations, especially focusing on the river mouth area. Sediments at 27 stations were examined during winter and summer to determine the major controlling factors for the distribution of metals, using correlation matrix and R-mode factor analyses, and to evaluate the pollution status, using the modified geoaccumulation (I(geo)(')) index. Temperatures for the effluent from the POSCO located at the Hyungsan river mouth were 2-3 degrees C higher compared to other sampling areas, due to the thermal discharge from the POSCO. The DO concentration of the surface water at the Pohang old port was as low as 2-4 mg/L. In spring, the DO value at the Hyungsan river mouth was higher than 12 mg/L, by the mass multiplication of phytoplanktons at the river mouth where seawater temperature and nutrients concentrations were relatively high, resulting in the pH value of higher than 8.3. The nitrogen to phosphorus (N/P) ratios at the river mouth were 20-150 times higher compared to other areas, implying that the nitrogen loading into this semi-enclosed bay is significantly higher than phosphorus and the major nitrogen sources are not only the domestic sewage from the city but the industrial wastewater from the POSCO and other steel factories nearby. The phosphorus concentrations at the Pohang old port were shown 3-10 times higher than those at other stations, due to the inflow of pollutants generated from the nearby ships anchoring and the release of phosphate from the bottom sediment. Results from the sediment

  14. Pyrosequencing evidence for iron-cycling microbial communities in sediments of the Skagerrak and Bothnian Bay

    Science.gov (United States)

    Reyes, Carolina; Dellwig, Olaf; Noriega-Ortega, Beatriz; Dähnke, Kirstin; Gehre, Matthias; Böttcher, Michael E.; Friedrich, Michael W.

    2015-04-01

    The diversity and metabolic pathways of microorganisms linked to Fe cycling in marine sediments are still poorly understood. Marine microorganisms in general are difficult to isolate and those that have been successfully isolated may not represent the main endogenous population. Various culture-independent techniques have been applied to characterize marine microbial communities, but only recently, has high throughput pyrosequencing been applied in marine sediment studies. Initial results are promising in capturing the full complexity of microbial communities in sediments. We performed a pyrosequencing-based study in marine and brackish sediments of the Baltic Sea; to our knowledge this is the first pyrosequencing study focused on the zone of Fe cycling. The goal of this study was to determine the bacterial and archaeal community composition near the sediment surface showing ongoing Fe cycling as a first step in characterizing the microorganisms potentially involved in Fe cycling. Two 35-cm-cores were sampled from ferruginous sediments in the Skagerrak, SK, North-Baltic Sea and the Bothnian Bay, BB, Northern Baltic Sea. Porewater (Fe2+, Mn2+, SO42-) and solid phase (Fe, Mn, total S) concentrations were measured and 16S rRNA genes were analysed using 454-pyrosequencing. Additionally, stable S and O isotope signatures of dissolved sulfate were measured at SK site. Sediment biogeochemistry indicated an intense suboxic zone with accumulation of dissolved Fe in the top 30 cm but only minor net sulfate (SO42-) reduction at both sites. Pore water profiles showed Fe2+ and Mn2+ levels of ~140-150 µM throughout the core below a 6 cm thick oxidized surface layer in SK sediments and ~300 µM below a 2 cm thick surface layer in BB sediments. Dissolved sulfide levels were below the detection limit in both sediments. Stable S and O isotope signatures suggest only minor net sulfate reduction. Fe reduction in the studied sediments is dominated by microbial dissimilatory Fe

  15. Seasonal changes of viable diatom resting stages in bottom sediments of Xiamen Bay, China

    Science.gov (United States)

    Chen, Chang-ping; Sun, Lin; Gao, Ya-hui; Zhou, Qian-qian; Zheng, Min-hua; Li, Bin-qian; Yu, Yang; Lu, Dou-ding

    2009-02-01

    The seasonal abundance of planktonic diatoms in the water column of Xiamen Bay, China, was investigated monthly during 2007 and 2008, and the viability of their resting stages in the bottom sediments was estimated using the extinction dilution method (most probable number method, MPN). The dominant genera in the planktonic diatom community were Skeletonema, Chaetoceros and Thalassiosira, whose viable resting stages were also the most abundant in the sediments. The highest concentration of viable diatom resting stages occurred 1 to 2 months after the maximum cell density of diatom communities occurred in the water column. The viability of Skeletonema resting cells increased in the sediments in either April or May at each station before the start of a Skeletonema bloom in June or July, suggesting that the germination of resting cells suspended in water could have influenced the blooming of Skeletonema species in the summer. Canonical correspondence analysis and multiple linear regression analysis revealed that the MPN of viable diatom resting stages was negatively correlated with silicate ( p concentration ( p > 0.05). The distribution of viable Chaetoceros resting spores and viable Skeletonema resting cells was different, possibly due to the different silicate cost in sea water during the formation of resting spores and resting cells, and also their survival ability in unfavorable environments.

  16. Chemistry and toxicity of sediments from San Diego Bay, including a biomarker (P450 RGS) response

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, J.W. [Columbia Analytical Services, Carlsbad, CA (United States); Newton, F.C.; Hardin, J. [MEC Analytical Systems, Carlsbad, CA (United States); Tukey, R.H. [Univ. of California, San Diego, CA (United States). Dept. of Pharmacology; Richter, K.E. [NRaD, San Diego, CA (United States)

    1996-12-31

    Thirty sediment samples were collected from the vicinity of the Naval Docking Facility in San Diego Bay and used to conduct bioassays with amphipods, oyster larvae, Microtox, and a new rapid screening test called the cytochrome P450 Reporter Gene System (RGS). This RGS cell line, from a human liver cancer cell, has been engineered to produce luciferase, when the CYP1A1 gene on the chromosome is induced by toxic and carcinogenic organics (dioxin, coplanar PCBs, PAHs). Elutriates were tested with both Microtox and oyster larvae, and organic extracts of sediments were tested with Microtox and the P450 RGS assay. Chemical analyses included total organic carbon (TOC), and acid volatile sulfides (AVS) along with a wide range of metals and organic chemicals. The simultaneously extracted metals (SEM) to AVS ratio was compared to the toxic response of oyster larvae and amphipods. Along each of the piers sampled, contaminant concentrations decreased with distance from shore. A correlation matrix analysis of all biological and chemical data was conducted. The strongest correlation between a chemical measurement and a biological response was that of total PAH versus the P450 RGS response. The use of P450 RGS as a screening tool to assess the relative risk of contaminants on sediments is biologically meaningful, and is a rapid and inexpensive means of determining which samples require complete chemical characterization.

  17. Investigation of petroleum residues and microbial PLFA in Barataria Bay sediments one year after the Deepwater Horizon oil spill

    Science.gov (United States)

    Clay, S.; Zimmerman, A. R.; Mahmoudi, N.; Silliman, B. R.; Slater, G. F.

    2012-12-01

    The Deepwater Horizon spill released crude oil into the Gulf of Mexico over a period of 3 months in 2010. Barataria Bay, Louisiana was among the most heavily impacted and extensively oil-contaminated coastlines. Studies conducted in the marshes show significant ecological and geologic effects from oil residues that reached the bay. Observation of the presence of an oil sheen associated with sediment disturbance raised the question as to whether petroleum residues were also present in the sediments of Barataria Bay. In order to address this question, six sediment cores were collected from non-oiled (#1 & 2) and oiled (#3-6) portions of Barataria Bay approximately one year after the Deepwater Horizon oil spill. Concentrations of n-alkanes, unresolved complex material (UCM) and polycyclic aromatic hydrocarbon (PAH) were determined in these upper sediments. In addition, concentrations of phospholipid fatty acids (PLFA) were determined to assess variations in microbial community abundance. Alkane concentrations ranged from 134 to 747 ng/g with chain lengths from C12 to C35. Most cores showed an odd over even preference (carbon preference index of 1.2 to 4.3) with highest concentrations of long chain compounds between C24 and C35 (average chain length 29 to 39), consistent with a terrestrial carbon source such as plant waxes. Core #6 however, in the southwest portion of the bay, had the lowest concentrations of alkanes, and shorter n-alkane chain lengths overall. Despite this difference, the core maintains a relatively high carbon preference index and average chain length compared to that which would be expected from oil contaminated sediments. Measured PAH concentrations were highly variable ranging from undetectable to 436 ng/g. These values are several orders of magnitude lower than what is generally seen in highly contaminated sediments. Further, UCM concentrations were negligible in the cores from the oiled regions. These findings suggest only a minimal presence of

  18. Ecosystem history of southern and central Biscayne Bay; summary report on sediment core analyses

    Science.gov (United States)

    Wingard, G.L.; Cronin, T. M.; Dwyer, G.S.; Ishman, S.E.; Willard, D.A.; Holmes, C.W.; Bernhardt, C.E.; Williams, C.P.; Marot, M.E.; Murray, J.B.; Stamm, R.G.; Murray, J.H.; Budet, C.

    2003-01-01

    of inter-decadal salinity extremes or periods of hypersalinity. o\tFreshwater and mesohaline salinities have had a minor influence on No Name bank throughout the time of deposition. At Featherbed Bank, the influence is reduced to mesohaline salinities. ?\tCard Bank has experienced relatively large swings in salinity over multi-decadal and centennial timescales, compared to central Biscayne Bay, but marine influence at the site has increased over the last century. ?\tIndications of regional scale patterns have been found, especially in the shell chemistry data and the pollen assemblages. These regional patterns indicate that the changes are not site specific and may not be limited to Biscayne Bay. ?\tSub-aquatic vegetation has undergone bay-wide patterns of change over the last 200-500 years, which includes expansion prior to 1900 and declines during the last century in central Biscayne Bay. o\tThalassia appears to have increased at all three core sites sometime between 1550 and 1750 AD. o\tA decline in Thalassia appears to have occurred after 1950 at No Name Bank and slightly earlier in the 20th century at Featherbed Bank. o\tCard Bank does not appear to have experienced any declines in vegetation on an inter-decadal scale during the 20th century. ?\tMolluscan faunal abundance and diversity have undergone significant changes in central Biscayne Bay. ?\tIndicators of increased organic-rich sediments at No Name occur between 1869 to 1888 and between the 1930's to 1975. These changes may correlate to human activities (settlement, population growth). These findings represent a first step towards the project's goal to reconstruct the history of Biscayne Bay and they provide us with a working model to be tested at other sites. It is clear from our findings that Biscayne Bay has been a dynamic environment over the last 500 years, with natural changes occurring in salinity and benthic habitats. However, several significant changes have occurred in the 20th ce

  19. Coupling between suboxic condition in sediments of the western Bay of Bengal and southwest monsoon intensification: A geochemical study

    Digital Repository Service at National Institute of Oceanography (India)

    Pattan, J.N; Mir, I.A; Parthiban, G.; Karapurkar, S.G.; Matta, V.M.; Naidu, P.D.; Naqvi, S.W.A

    Reconstruction of paleo-redox conditions in a radiocarbon (14C) dated sediment core (SK-218/1), covering the past 45 ka (thousand calendar years), collected from the western Bay of Bengal (Lat: 14 degrees 02′N; Long: 82 degrees 00′E) at a water...

  20. Quantifying Relationships between Water Quality and Aquatic Life Use Attainment using Sediment Profile Imagery (SPI) in Pensacola Bay

    Science.gov (United States)

    We present results from a monthly sediment and water quality survey of nine stations along a transect in the Pensacola Bay estuary spanning the salinity gradient from Escambia River to the Gulf of Mexico. We evaluated Benthic Habitat Quality (Nilsson and Rosenberg 1997) derived f...

  1. High Prevalence of Gammaproteobacteria in the Sediments of Admiralty Bay and North Bransfield Basin, Northwestern Antarctic Peninsula

    Science.gov (United States)

    Franco, Diego C.; Signori, Camila N.; Duarte, Rubens T. D.; Nakayama, Cristina R.; Campos, Lúcia S.; Pellizari, Vivian H.

    2017-01-01

    Microorganisms dominate most Antarctic marine ecosystems, in terms of biomass and taxonomic diversity, and play crucial role in ecosystem functioning due to their high metabolic plasticity. Admiralty Bay is the largest bay on King George Island (South Shetland Islands, Antarctic Peninsula) and a combination of hydro-oceanographic characteristics (bathymetry, sea ice and glacier melting, seasonal entrance of water masses, turbidity, vertical fluxes) create conditions favoring organic carbon deposition on the seafloor and microbial activities. We sampled surface sediments from 15 sites across Admiralty Bay (100–502 m total depth) and the adjacent North Bransfield Basin (693–1147 m), and used the amplicon 454-sequencing of 16S rRNA gene tags to compare the bacterial composition, diversity, and microbial community structure across environmental parameters (sediment grain size, pigments and organic nutrients) between the two areas. Marine sediments had a high abundance of heterotrophic Gammaproteobacteria (92.4% and 83.8% inside and outside the bay, respectively), followed by Alphaproteobacteria (2.5 and 5.5%), Firmicutes (1.5 and 1.6%), Bacteroidetes (1.1 and 1.7%), Deltaproteobacteria (0.8 and 2.5%) and Actinobacteria (0.7 and 1.3%). Differences in alpha-diversity and bacterial community structure were found between the two areas, reflecting the physical and chemical differences in the sediments, and the organic matter input. PMID:28210255

  2. SEDIMENT TOXICITY AND COMMUNITY COMPOSITION OF BENTHOS AND COLONIZED PERIPHYTON IN THE EVERGLADES - FLORIDA BAY TRANSITIONAL ZONE.

    Science.gov (United States)

    Lewis, Michael A., Larry R. Goodman, John M. Macauley and James C. Moore. 2004. Sediment Toxicity and Community Composition of Benthos and Colonized Periphyton in the Everglades-Florida Bay Transitional Zone. Ecotoxicology. 13(3):231-244. (ERL,GB 1164). This survey provid...

  3. Assessing past and present P Retention in Sediments in Lake Ontario (Bay of Quinte) by Reaction-Transport Diagenetic Modeling

    Science.gov (United States)

    Doan, Phuong; Berry, Sandra; Markovic, Stefan; Watson, Sue; Mugalingam, Shan; Dittrich, Maria

    2016-04-01

    Phosphorus (P) is an important macronutrient that can limit aquatic primary production and the risk of harmful algal blooms. Although there is considerable evidence that P release from sediments can represent a significant source of P and burial in sediments returns P to the geological sink; these processes have been poorly characterised. In this study, we applied a non-steady state reactive transport diagenetic model to gain insights into the dynamics of phosphorus binding forms in sediments and the phosphorus cycling of the Bay of Quinte, an embayment of Lake Ontario, Canada. The three basins of the bay (Belleville, Hay Bay and Napanee) that we investigated had differences in their phosphorus binding forms and phosphorus release, reflecting the distinct spatial temporal patterns of land use and urbanization levels in the watershed. Sediment cores from the three stations were collected during summer and under ice cover in 2013-14. Oxygen, pH and redox potential were monitored by microsensors; porewater and sediment solid matter were analyzed for P content, and a sequential extraction was used to analyze P binding forms. In the reaction-transport model, total phosphorus was divided into adsorbed phosphorus, phosphorus bound with aluminium, organic phosphorus, redox sensitive and apatite phosphorus. Using the fluxes of organic and inorganic matter as dynamic boundary conditions, we simulated the depth profiles of solute and solid components. The model closely reproduced the fractionation data of phosphorus binding forms and soluble reactive phosphorus. The past and present P fluxes were calculated and estimated; they related to geochemical conditions, and P binding forms in sediments. Our results show that P release from sediments is dominated by the redox-sentive P fraction accounting for higher percentage at Napanee station. The main P binding form that can be immobilized through diagenesis is apatite P contributing highest P retention at HayBay station. The mass

  4. Sediment dynamic responses of coastal salt marsh to typhoon "KAEMI" in Quanzhou Bay, Fujian Province, China

    Institute of Scientific and Technical Information of China (English)

    WANG AiJun; GAO Shu; GHEN Jian; LI DongYi

    2009-01-01

    In order to understand the mechanisms of coastal protection by salt marshes during typhoon events, in situ measurements of water level, tidal current speed and direction, and suspended sediment concen-tration (SSC) were carried out using Electromagnetic Current Meter (EMCM, AEM HR), miniature pres-sure sensor (MkV/D) and Seapoint Turbidity Meter (STM) sensor on a tidal flat in Quanzhou Bay, during the period when the typhoon "KAEMI" was passing through the region. The analysis of the data ob-tained shows that the near-bed current speed within the Spartina alterniflora marsh was generally be-low 5 cm s-1, which was apparently smaller than on the adjacent bare flat (I.e. 5-30 cm s-1). The change in the near-bed current speed in response to the typhoon event was not significant within the S. Al-terniflora marsh, but the current direction was influenced by the typhoon. The effect of the typhoon on the SSC was highly significant, with the SSC reaching 13 to 19 times the values on the bare flat or within the marsh under fair weather conditions; the near-bed SSC within the marsh was higher than on the bare flat, after the typhoon landed. The near-bed suspended sediment fluxes within the marsh and on the bare flat during the typhoon event were both enhanced, I.e., 4 times larger than under fair weather conditions. During the ebb, the bottom shear stress on the bare flat exceeded the critical shear stress for sediment motion for most of the ebb duration of the tide and, therefore, the bed sediment was eroding, with the erosion flux after the typhoon landed being around 2 to 3 times the value associated with fair weather conditions. In contrast, within the S. Alterniflora marsh, the bottom shear stress was mostly lower than the critical shear stress for sediment motion, or lower than the critical shear stress for the maintenance of suspension; hence, the marsh surface was dominated by settling processes, with a settling flux during the typhoon being 3 to 6 times compared

  5. Sediment depositional environment in some bays in Central west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Rajamanickam, G.V.; Gujar, A.R.

    minerals data show a positive correlation with mean grain size in Kalbadevi Bay but negative correlation in Ratnagiri Bay, whereas they show an unharmonic relationship with sorting. Considering similar hydraulic conditions in all the bays, the existence...

  6. Seasonal variability in the surface sediments of Mobile Bay, Alabama, recorded by geochemistry and foraminifera, 2009–2010

    Science.gov (United States)

    Umberger, D.K.; Osterman, L.E.; Smith, C.G.; Frazier, J.; Richwine, K.A.

    2012-01-01

    A study was undertaken in order to document and quantify recent environmental change in Mobile Bay, Alabama. The study was part of the Northern Gulf of Mexico (NGOM) Ecosystem Change and Hazard Susceptibility project, a regional project funded by the Coastal and Marine Geology Program to understand how natural forcings and anthropogenic modifications influence coastal ecosystems and their susceptibility to coastal hazards. Mobile Bay is a large drowned-river estuary that has been modified significantly by humans to accommodate the Port of Mobile. Examples include repeated dredging of a large shipping channel down the central axis of the bay and construction of a causeway across the head of the bay and at the foot of the bayhead delta. In addition to modifications, the bay is also known to have episodic periods of low oxygen (hypoxia) that result in significant mortality to fish and benthic organisms (May, 1973). For this study a series of surface sediment samples were collected. Surface benthic foraminiferal and bulk geochemical data provide the modern baseline conditions of the bay and can be used as a reference to changing environmental parameters in the past (Osterman and Smith, in press) and into the future. This report archives data collected as part of the Mobile Bay Study that may be used in future environmental change studies.

  7. Speciation of Metals and Assessment of Contamination in Surface Sediments from Daya Bay, South China Sea

    Directory of Open Access Journals (Sweden)

    Jie Yang

    2014-12-01

    Full Text Available The contents, speciation, source factors and potential ecological risks of the selected metals (Cr, Ni, Cu, Pb, Zn, Cd and As were analyzed in surface sediments from Daya Bay (DYB. The results show that, with the exception of Pb, metal concentrations have decreased at all sites over the past decade. The distribution features of these concentrations represent a ring shape that descends from shore to bay by varying degrees. Speciation analysis showed that Cr, Ni, Cu, Zn and As exist mainly in the residual fraction and, thus, are of low bioavailability, while Cd and Pb were found to be abundant in the non-residual fraction and, thus, have high potential mobility. The ratio of heavy metals in non-residual form in descending order is Pb (78.83%, Cd (78.65%, Cu (48.54%, Zn (48.10%, Ni (38.31%, Cr (28.43% and As (27.76%. The ratio of Pb content is the highest, meaning the highest mobility of Pb. The metals’ potential ecological risks to the environment were also assessed using the methods of the mean effect range-median quotient and the criteria of risk assessment code. The results showed that Cd presents the highest risk, and Pb and Cu are generally considered to be medium risks in the sub-basins of Daya Bay. The principal component analysis (PCA revealed that natural coastal weathering and erosion of rock caused the highest input, followed by mariculture and industrial wastewater and, finally, domestic sewage discharge.

  8. Microbial Mercury Cycling in San Francisco Bay Sediments: From Regions to the Rhizosphere

    Science.gov (United States)

    Evans, V. A.; Mann, A.; Romeis, J.; Marvin-Dipasquale, M. C.; Agee, J. L.; Kieu, L. H.; Harms, H. A.

    2004-05-01

    The San Francisco Bay (SFB) estuary is hydrodynamically diverse ecosystem with extensive mercury contamination associated with historic gold and mercury mining wastes, and in a region with an unprecedented number of wetland restoration projects planned or ongoing. Wetlands are known to be active areas for the microbial transformation of Hg(II) to methylmercury (MeHg), which bioaccumulates in the food web. A better understanding of this microbial process, in these restored wetlands and other sub-habitats, is critical if Hg contamination is to be successfully managed in this system. An examination of MeHg production and degradation in sediments has been conducted at multiple spatial scales throughout the SFB estuary and its tributaries over the past four years. At the regional scale, we will present data from the brackish Bay, the delta, and rivers and reservoirs in tributary watersheds. Within the freshwater delta and river regions, a new project is focusing on emergent marsh, non-vegetated open water, and submerged-macrophyte zones. At the smallest scale, we consider microbial Hg cycling in the root zone (rhizosphere) of dominant wetland plants and propose a conceptual model of the key biogoechemical reactions that may make this transitional zone one of the most important with respect to Hg(II)-methylation.

  9. Carbon sources supporting benthic mineralization in mangrove and adjacent seagrass sediments (Gazi Bay, Kenya

    Directory of Open Access Journals (Sweden)

    F. Dehairs

    2004-08-01

    Full Text Available The origin of carbon substrates used by in situ sedimentary bacterial communities was investigated in an intertidal mangrove ecosystem and in adjacent seagrass beds in Gazi bay (Kenya by δ13C analysis of bacteria-specific PLFA (phospholipid fatty acids and bulk organic carbon. Export of mangrove-derived organic matter to the adjacent seagrass-covered bay was evident from sedimentary total organic carbon (TOC and δ13CTOC data. PLFA δ13C data indicate that the substrate used by bacterial communities varied strongly and that exported mangrove carbon was a significant source for bacteria in the adjacent seagrass beds. Within the intertidal mangrove forest, bacterial PLFA at the surface layer (0-1 cm typically showed more enriched δ13C values than deeper (up to 10 cm sediment layers, suggesting a contribution from microphytobenthos and/or inwelled seagrass material. Under the assumption that seagrasses and mangroves are the dominant potential end-members, the estimated contribution of mangrove-derived carbon to benthic mineralization in the seagrass beds (16-74% corresponds fairly well to the estimated contribution of mangrove C to the sedimentary organic matter pool (21-71% across different seagrass sites. Based on these results and a compilation of literature data, we suggest that allochtonous carbon trapped in seagrass beds may often represent a significant fraction of the substrate for benthic mineralization - both in cases where seagrass C dominates the sediment TOC pool and in cases where external inputs are significant. Hence, it is likely that community respiration data systematically overestimate the role of mineralization in the overall seagrass C budget.

  10. Reconstruction of metal pollution and recent sedimentation processes in Havana Bay (Cuba): A tool for coastal ecosystem management

    Energy Technology Data Exchange (ETDEWEB)

    Diaz-Asencio, M., E-mail: misael@ceac.cu [Centro de Estudios Ambientales de Cienfuegos, Carretera Castillo de Jagua, Cienfuegos, CITMA-Cienfuegos (Cuba); Alvarado, J.A. Corcho [Institute of Radiation Physics (IRA), University Hospital and University of Lausanne, Rue du Grand-Pre 1, 1007 Lausanne (Switzerland); Alonso-Hernandez, C. [Centro de Estudios Ambientales de Cienfuegos, Carretera Castillo de Jagua, Cienfuegos, CITMA-Cienfuegos (Cuba); Quejido-Cabezas, A. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Madrid (Spain); Ruiz-Fernandez, A.C. [Universidad Nacional Autonoma de Mexico. ICMyL, Mazatlan (Mexico); Sanchez-Sanchez, M.; Gomez-Mancebo, M.B. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Madrid (Spain); Froidevaux, P. [Institute of Radiation Physics (IRA), University Hospital and University of Lausanne, Rue du Grand-Pre 1, 1007 Lausanne (Switzerland); Sanchez-Cabeza, J.A. [Institute of Environmental Science and Technology, and Physics Department, Universitat Autonoma de Barcelona, 08193 Bellaterra, Barcelona (Spain)

    2011-11-30

    Highlights: Black-Right-Pointing-Pointer Past metal pollution in the heavy polluted coastal ecosystem of Havana Bay. Black-Right-Pointing-Pointer Effectiveness of pollution-reduction strategies. Black-Right-Pointing-Pointer Dated environmental archives to reconstruct sedimentation and pollution trends. Black-Right-Pointing-Pointer Impact of severe climatic events on sedimentation. - Abstract: Since 1998 the highly polluted Havana Bay ecosystem has been the subject of a mitigation program. In order to determine whether pollution-reduction strategies were effective, we have evaluated the historical trends of pollution recorded in sediments of the Bay. A sediment core was dated radiometrically using natural and artificial fallout radionuclides. An irregularity in the {sup 210}Pb record was caused by an episode of accelerated sedimentation. This episode was dated to occur in 1982, a year coincident with the heaviest rains reported in Havana over the XX century. Peaks of mass accumulation rates (MAR) were associated with hurricanes and intensive rains. In the past 60 years, these maxima are related to strong El Nino periods, which are known to increase rainfall in the north Caribbean region. We observed a steady increase of pollution (mainly Pb, Zn, Sn, and Hg) since the beginning of the century to the mid 90s, with enrichment factors as high as 6. MAR and pollution decreased rapidly after the mid 90s, although some trace metal levels remain high. This reduction was due to the integrated coastal zone management program introduced in the late 90s, which dismissed catchment erosion and pollution.

  11. Impact of a river system on carbon sedimentation and sequestration in Cook's Bay of Lake Simcoe, Ontario

    Science.gov (United States)

    Blodau, Christian; Agethen, Svenja; Spangenberg, Ines; Broder, Tanja; Gimbel, Nicole; Strauss, Harald; Knorr, Klaus-Holger

    2016-04-01

    The influence of sedimentation rates and organic matter quality on carbon sequestration and mineralization at the land-water interface of lakes is not well understood. To study this issue we investigated shallow Cook's Bay of temperate Lake Simcoe in southern Ontario. The elongated bay provides gradients in morphometry, trophic level, and distance to a major tributary as a potential point source of nutrients and terrestrial organic carbon. At five sampling sites of increasing distance to the river outlet the water column was examined during stratification regarding physio-chemical parameters, dissolved organic matter (DOM) characteristics, sedimentation rates and mineralization of settling material and sediments. To quantify actual organic carbon burial, sedimentation rates and mineralization were determined in situ and by diffusive flux modeling. Long-term carbon burial and sedimentation rates were determined using 210Pb dated sediment cores. Organic carbon quality and origin were analyzed in water samples via fluorescence spectroscopy, solid DOM and settling particles via elemental analysis and 13C isotopic data. Results showed that actual and long-term carbon burial were highest at the central sites of the transect (52-63%) and lowest at the profundal sites (0-25%). Current organic carbon deposition was highest near the river outlet (max. 0.3 g C m-2 d-1) and there the settling material reaching the sediments and in the sediments was also most highly decomposable. Total sedimentation rates and organic carbon burial were closely related. Compared to the outer sites, the DOM quality was significantly different at the site closest to the river outlet but already strongly influenced by lacustrine carbon cycling. Permanent organic carbon burial was mainly influenced by sedimentation related to lake morphometry and dependent parameters. The relation between sedimentation and carbon burial rates underlined the importance of oxygen exposure time and burial for

  12. Temporal changes in TBT pollution in water, sediment, and oyster from Jinhae Bay after the total ban in South Korea.

    Science.gov (United States)

    Kim, Nam Sook; Hong, Sang Hee; Yim, Un Hyuk; Shin, Kyung-Hoon; Shim, Won Joon

    2014-09-15

    Temporal change in tributyltin (TBT) levels in Jinhae Bay, which has various TBT sources, was investigated in water, sediments, and oysters from 2003 to 2013 after its total ban in South Korea. The seawater TBT levels decreased over 500-fold from 1995/97 to 2008/09. The oyster TBT levels were about fourfold lower in 2012/13 than in 1995/97. However, the sediment TBT levels did not significantly change, even 10 years after the partial TBT ban on small ships and 7 years after the total TBT ban on all oceangoing vessels in Korea. The total ban of TBT use effectively reduced water and oyster TBT levels in Jinhae Bay, but TBT levels in water, oysters, and sediment remained above the global environmental quality standards established to protect marine organisms.

  13. Comparison of wastewater-associated contaminants in the bed sediment of Hempstead Bay, New York, before and after Hurricane Sandy

    Science.gov (United States)

    Fisher, Shawn C.; Phillips, Patrick; Brownawell, Bruce J.; Browne, James

    2016-01-01

    Changes in bed sediment chemistry of Hempstead Bay (HB) have been evaluated in the wake of Hurricane Sandy, which resulted in the release of billions of liters of poorly-treated sewage into tributaries and channels throughout the bay. Surficial grab samples (top 5 cm) collected before and (or) after Hurricane Sandy from sixteen sites in HB were analyzed for 74 wastewater tracers and steroid hormones, and total organic carbon. Data from pre- and post-storm comparisons of the most frequently detected wastewater tracers and ratios of steroid hormone and of polycyclic aromatic hydrocarbon concentrations indicate an increased sewage signal near outfalls and downstream of where raw sewage was discharged. Median concentration of wastewater tracers decreased after the storm at sites further from outfalls. Overall, changes in sediment quality probably resulted from a combination of additional sewage inputs, sediment redistribution, and stormwater runoff in the days to weeks following Hurricane Sandy.

  14. Definition of a mobilizing volume of sediment in a valley interested by volcanic eruption: Rio Blanco valley (Chile)

    Science.gov (United States)

    Oss-Cazzador, Daniele; Iroumé, Andrés; Picco, Lorenzo

    2016-04-01

    Volcanic explosive activity can strongly affect the riverine environments. Deposition of tephra, pyroclastic and hyperconcentrated flows along both the valley bottom and hillslopes can radically change the environmental morphology. Accumulation and transport of pyroclastic material can increase hazards and risks for anthropic activities. The aims of this research are to evaluate and quantify the amount of erodible sediment that can be transported along a gravel bed river affected by a volcanic eruption. The Rio Blanco valley (Chile) was upset by the plinian-type eruption of Chaiten volcano in 2008. The great amount of tephra released in the initial phase and the subsequent pyroclastic flows, accumulated up to 8 m of sediment over a great portion of the Rio Blanco valley. Using aerial photographs was possible to define the extension of vegetated zones affected by the eruption. The area was interested by a high mortality of vegetation, as confirmed by field surveys. Dendrometric measurements permitted to quantify the volume of wood and observe that renewal and herbal layer are almost absent, determining low soil cohesion and easier erosion by superficial and river erosion processes. Analysis of sediment accumulation allowed quantifying the volume of sediment that can be transported downstream. The analyses were carried out considering 7 km-long a reach, from the river mouth to the confluence between Caldera creek and Rio Blanco. After the eruption, was possible to define as a total area of about 2.19 km2 was affected by tephra deposition, the 40% (0,87 km2) was eroded by flows, while 60% (1,32 km2) is still present and composed by tephra, buried large wood (LW) and dead standing trees. Considering an average high of 5 m, the potential erodible sediment is around 6,5 x 106 m3, moreover there is a potential amount of about 7,3 x 104 m3 of LW that can be transported towards mouth. These analyses can be useful to better define the management plan for the river delta. In

  15. Effects of dam construction on sediment phosphorus variation in a semi-enclosed bay of the Seto Inland Sea, Japan

    Science.gov (United States)

    Jin, Guangzhe; Onodera, Shin-ichi; Amano, Atsuko; Saito, Mitsuyo; Shimizu, Yuta; Satou, Takaharu

    2013-12-01

    This study investigated the effects of dam construction on sediment phosphorus concentrations in a semi-enclosed bay in western Japan. Long sediment core samples spanning over 100 years were collected from the bay, and their P fractions were analyzed. Sediment P concentrations and the P accumulation rate in an artificial lake increased after the construction of a coastal dam in 1959. The amount of P accumulated in the 60 years after the dam construction was ˜1.7 times that prior to the dam construction. Moreover, concentrations of mobile forms of P, primarily redox-sensitive P species, were higher in freshwater sediments above the dam than in saline sediments below the dam. The redox-sensitive forms of P in freshwater sediments increased sharply after the dam construction, from 100 to ˜900 μg/g, accompanied by a decrease in chloride (Cl-) concentrations to 1980s, the lake still has a high trophic level. The presently high mobile P concentrations in surface sediments may lead to high-magnitude P releases with environmental changes in the future.

  16. Composition and depth distribution of hydrocarbons in Barataria Bay marsh sediments after the Deepwater Horizon oil spill.

    Science.gov (United States)

    Dincer Kırman, Zeynep; Sericano, José L; Wade, Terry L; Bianchi, Thomas S; Marcantonio, Franco; Kolker, Alexander S

    2016-07-01

    In 2010, an estimate 4.1 million barrels of oil were accidentally released into the Gulf of Mexico (GoM) during the Deepwater Horizon (DWH) Oil Spill. One and a half years after this incident, a set of subtidal and intertidal marsh sediment cores were collected from five stations in Barataria Bay, Louisiana, USA, and analyzed to determine the spatial and vertical distributions and source of hydrocarbon residues based on their chemical composition. An archived core, collected before the DWH oil spill from the same area, was also analyzed to assess the pre-spill hydrocarbon distribution in the area. Analyses of aliphatic hydrocarbons, polycyclic aromatic hydrocarbons (PAHs) and stable carbon isotope showed that the distribution of petroleum hydrocarbons in Barataria Bay was patchy and limited in areal extent. Significant TPH and ΣPAH concentrations (77,399 μg/g and 219,065 ng/g, respectively) were detected in the surface sediments of one core (i.e., core A) to a depth of 9 cm. Based on a sedimentation rate of 0.39 cm yr(-1), determined using (137)Cs, the presence of anthropogenic hydrocarbons in these sediment core deposited ca. 50 to 60 years ago. The historical background hydrocarbon concentrations increased significantly at the sediment surface and can be attributed to recent inputs. Although the oil present in the bay's sediments has undergone moderate weathering, biomarker analyses performed on core A samples likely indicated the presence of hydrocarbons from the DWH oil spill. The effects of oiling events on Barataria Bay and other marsh ecosystems in this region remain uncertain, as oil undergoes weathering changes over time.

  17. Evaluation of Soil Erosion and Sediment Yield from Ridge Watersheds Leading to Guánica Bay, Puerto Rico, Using SWAT Model

    Science.gov (United States)

    Increased sediment loading to reservoirs and, ultimately, to Guánica Bay and reef areas is a significant concern in Puerto Rico. Sediment deposition has significantly reduced storage capacity of reservoirs, and sediment-attached contaminants can stress corals and negative...

  18. Glaciomarine sedimentation and landforms in Admiralty Bay, South Shetland Islands, Antarctica

    Science.gov (United States)

    Magrani, Fabio; Ayres Neto, Arthur; Vieira, Rosemary

    2015-04-01

    This work consists on the integration and interpretation of high-resolution seismic profiles, geological sampling and multibeam bathymetry in order to analyze and understand the evolution of the deglaciation of Admiralty Bay, South Shetland Islands, Antarctica, since the Last Glacial Maximum (LGM). Data were obtained from three expeditions to Antarctica between 2009 and 2013, totaling 500 km of seismic lines and five geological cores. The characterization of the bottom geology was performed by analyzing the echocharacters and the sedimentary thickness of the glaciomarine deposits. Its correlation with the collected samples provided interpretation of the depositional paleoenvironments, allowing the reconstruction and evolution of the glaciers since the LGM and the recognition of glaciomarine processes. Multibeam bathymetry also provided records of submarine landforms related to glacial events and changes in positions of glaciers in the region. In this way, we ought to answer the question: which glaciomarine records are present in Admiralty Bay that can broaden our understanding of the evolution of its deglaciation during the advances and retreats of glaciers that once dominated the fjord, and its sedimentary processes? Four different echocharacters have been identified. Echoes I and II show good resolution and are characterized by continuous and sharp echoes with sub-parallel reflections and the presence of glaciomarine muds. Very prolonged echoes and absence of sub-parallel reflectors characterizes Echoes III and IV. Eco III is associated with the shallower portions of the bay, with little sediment thickness, sandier content and presence of ice rafted debris. Eco IV is associated with morainical banks and grounding zones. Seabed landform features show that the region experienced major glacial advance, with subsequent rapid retreat of the glaciers in the deeper parts of the fjord, followed by slower retreat, with the presence of several recessional moraines in the

  19. 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.

  20. Sedimentology and preservation of aeolian sediments on steep terrains: Incipient sand ramps on the Atacama coast (northern Chile)

    Science.gov (United States)

    Ventra, Dario; Rodríguez-López, Juan Pedro; de Boer, Poppe L.

    2017-05-01

    The origin of topographically controlled aeolian landforms in high-relief settings is difficult to synthesize under general models, given the dependence of such accumulations on local morphology. Quaternary sand ramps have been linked to palaeoclimate, regional geomorphology and wind patterns; however, controls on the early development and preservation of such landforms are poorly known. This study describes the morphology and sedimentology of complex sedimentary aprons along steep coastal slopes in the Atacama Desert (Chile). Direct slope accessibility and continuous stratigraphic exposures enable comparisons between active processes and stratigraphic signatures. Stratigraphic facies distribution and its links with patterns of aeolian deposition show that the preservation of wind-laid sediments depends on the morphology and processes of specific slope sectors. The spatial organization of runoff depends on bedrock configuration and directly controls the permanence or erosion of aeolian sediment. The occurrence of either water or mass flows depends on the role of aeolian fines in the rheology of flash floods. In turn, the establishment of a rugged surface topography controlled by patterns of mass-flow deposition creates local accommodation for aeolian fines, sustaining the initial aggradation of a colluvial-aeolian system. By contrast, slopes subject to runoff develop a thin, extensive aeolian mantle whose featureless surface is subject mostly to sediment bypass down- and across-slope; the corresponding stratigraphic record comprises almost exclusively thin debris-flow and sheetflood deposits. Slope morphology and processes are fundamental in promoting or inhibiting aeolian aggradation in mountain settings. Long-term sand-ramp construction depends on climate and regional topography, but the initial development is probably controlled by local geomorphic factors. The observed interactions between wind and topography in the study area may also represent a process

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

    Science.gov (United States)

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

    2010-12-01

    The spatial distribution of As (total As, As (III) and As (V)) in estuarine sediments from the main tributaries of Todos os Santos Bay, BA, Brazil, was evaluated under high and low flow conditions. The concentrations of As were determined using a slurry sampling procedure with hydride generation atomic absorption spectrometry (HG-AAS). The highest concentrations were observed at estuary mouths, and exceeded conservative lower threshold value (Threshold Effects Level; TEL). Due to the oxic conditions and abundance of Mn and Fe (oxyhydr)oxides in the sediments, most inorganic arsenic in the Subaé and Paraguaçu estuaries was present as As (V). Nevertheless, the concentration of As (III) at several locations along the Jaguaripe River were also above the TEL value, suggesting that As may be toxic to biota. In the Subaé estuary, antropogenic activities are the main source of As. At the Jaguaripe and at Paraguaçu estuaries, nevertheless, natural sources of As need to be considered to explain the distribution patterns. Copyright © 2010 Elsevier Ltd. All rights reserved.

  2. Brominated diphenyl ethers in the sediments, porewater, and biota of the Chesapeake Bay, USA

    Energy Technology Data Exchange (ETDEWEB)

    Baker, K.; Klosterhaus, S.; Liebert, D.; Stapleton, H. [Maryland Univ., Solomons, MD (United States)

    2004-09-15

    Levels of brominated diphenyl ethers (BDEs) are rapidly increasing in the environment, and in a short time these chemicals have evolved from 'emerging contaminants' to globally-distributed organic pollutants. Recent research demonstrates BDEs are sufficiently stable to be transported long distances in the environment and to accumulate in higher trophic levels. Photolysis and metabolism appear to be dominant loss processes for the parent compounds, generating a variety of lower brominated diphenyl ethers, hydroxylated metabolites, and other products. BDEs are hydrophobic, and therefore their transport in aquatic systems is likely controlled by sorption to sediments and perhaps exchange across the air-water interface. To date, few studies have examined the geochemistry of BDEs in natural waters. In this paper, we review our recent measurements of BDEs in the Chesapeake Bay, a shallow, productive estuary in eastern North America. We focus on the distribution of BDE congeners sediment, porewater, and in faunal benthos along a contamination gradient downstream from a wastewater treatment plant and on the spatial distribution of BDEs in bottom-feeding and pelagic fish species.

  3. Seafloor geomorphology and glacimarine sedimentation associated with fast-flowing ice sheet outlet glaciers in Disko Bay, West Greenland

    Science.gov (United States)

    Streuff, Katharina; Ó Cofaigh, Colm; Hogan, Kelly; Jennings, Anne; Lloyd, Jeremy M.; Noormets, Riko; Nielsen, Tove; Kuijpers, Antoon; Dowdeswell, Julian A.; Weinrebe, Wilhelm

    2017-08-01

    Fast-flowing outlet glaciers currently drain the Greenland Ice Sheet (GIS), delivering ice, meltwater and debris to the fjords around Greenland. Although such glaciers strongly affect the ice sheet's mass balance, their glacimarine processes and associated products are still poorly understood. This study provides a detailed analysis of lithological and geophysical data from Disko Bay and the Vaigat Strait in central West Greenland. Disko Bay is strongly influenced by Jakobshavn Isbræ, Greenland's fastest-flowing glacier, which currently drains ∼7% of the ice sheet. Streamlined glacial landforms record the former flow of an expanded Jakobshavn Isbræ and adjacent GIS outlets through Disko Bay and the Vaigat Strait towards the continental shelf. Thirteen vibrocores contain a complex set of lithofacies including diamict, stratified mud, interbedded mud and sand, and bioturbated mud deposited by (1) suspension settling from meltwater plumes and the water column, (2) sediment gravity flows, and (3) iceberg rafting and ploughing. The importance of meltwater-related processes to glacimarine sedimentation in West Greenland fjords and bays is emphasised by the abundance of mud preserved in the cores. Radiocarbon dates constrain the position of the ice margin during deglaciation, and suggest that Jakobshavn Isbræ had retreated into central Disko Bay before 10.6 cal ka BP and to beyond Isfjeldsbanken by 7.6-7.1 cal ka BP. Sediment accumulation rates were up to 1.7 cm a-1 for ice-proximal glacimarine mud, and ∼0.007-0.05 cm a-1 for overlying distal sediments. In addition to elucidating the deglacial retreat history of Jakobshavn Isbræ, our findings show that the glacimarine sedimentary processes in West Greenland are similar to those in East Greenland, and that variability in such processes is more a function of time and glacier proximity than of geographic location and associated climatic regime.

  4. 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.

  5. Geochemical records of phosphorus in Jiaozhou Bay sediments-Implications for environmental changes in recent hundred years

    Institute of Scientific and Technical Information of China (English)

    DAI Jicui; SONG Jinming; LI Xuegang; YUAN Huamao; ZHENG Guoxia; LI Ning

    2007-01-01

    Phosphorus is a key element and plays an important role in global biogeochemical cycles. The evolution of sedimentary environment is also influenced by phosphorus concentrations and fractions as well as phosphate sorption characteristics of the marine sediments. The geochemical characteristics of phosphorus and their environmental records were presented in Jiaozhou Bay sediments.Profiles of different forms of phosphorus were measured as well as the roles and vertical distributions of phosphorus forms in response to sedimentary environment changes were investigated. The results showed that inorganic phosphorus (IP) was the major fraction of total phosphorus (TP); phosphorus which is bound to calcium, iron and occluded phosphorus, as well as the exchangeable phosphorus were the main forms of IP, especially calcium - phosphorus, including detrital carbonate-bound phosphorus (Det- P) and authigenic apatite-bound phosphorus (ACa- P), are the uppermost constituent of IP in Jiaozhou Bay sediments. Moreover, the lead-210 chronology technology was employed to estimate how much phosphorus was buried ultimately in sediments. And the research showed that the impacts of human activities have increased remarkably in recent years especially between the 1980s and 2000. According to research, the development of Jiaozhou Bay environment in the past hundred years can be divided into three stages: (1) before the 1980s characterized by the relatively low sedimentation rate, weak land-derived phosphorus inputs and low anthropogenic impacts; (2) from the 1980s to around 2000, accelerating in the 1990s, during which high sedimentation rates, high phosphorus abundance and burial fluxes due to the severe human activities impacted on the whole environmental system; (3) after 2000, the period of the improvement of environment, the whole system has been improved including the decreasing sedimentation rates, concentration and the burial fluxes of phosphorus.

  6. Distribution of total mercury in surface sediments of the western Jade Bay, Lower Saxonian Wadden Sea, southern North Sea.

    Science.gov (United States)

    Jin, Huafang; Liebezeit, Gerd; Ziehe, Daniel

    2012-04-01

    A total of 114 surface sediment samples was equidistantly collected in the western part of the Jade Bay, southern North Sea, to analyse total mercury contents as well as grain size distribution and total organic carbon (TOC) contents. Total mercury was determined by oxygen combustion-gold amalgamation. Validation, precision and accuracy of the method were evaluated and controlled with two certified reference materials (HISS-1 and MESS-3). Total mercury contents varied between 8 and 243 ng/g dry sediment with a mean value of 103 ng/g dw. The mercury levels in surface sediments showed an inhomogeneous spatial distribution with higher contents in near-dike areas. The values are mostly in the range of natural background values (50–100 ng/g dw) and positively related to TOC and clay/silt contents (Jade Bay are not mercury contaminated. These results also suggested that the current mercury contents of Jade Bay surficial sediments are mostly affected by atmospheric deposition and re-emission.

  7. Increased terrestrial to ocean sediment and carbon fluxes in the northern Chesapeake Bay associated with twentieth century land alteration

    Science.gov (United States)

    Saenger, C.; Cronin, T. M.; Willard, D.; Halka, J.; Kerhin, R.

    2008-01-01

    We calculated Chesapeake Bay (CB) sediment and carbon fluxes before and after major anthropogenic land clearance using robust monitoring, modeling and sedimentary data. Four distinct fluxes in the estuarine system were considered including (1) the flux of eroded material from the watershed to streams, (2) the flux of suspended sediment at river fall lines, (3) the burial flux in tributary sediments, and (4) the burial flux in main CB sediments. The sedimentary maximum in Ambrosia (ragweed) pollen marked peak land clearance (~1900 a.d.). Rivers feeding CB had a total organic carbon (TOC)/total suspended solids of 0.24??0.12, and we used this observation to calculate TOC fluxes from sediment fluxes. Sediment and carbon fluxes increased by 138-269% across all four regions after land clearance. Our results demonstrate that sediment delivery to CB is subject to significant lags and that excess post-land clearance sediment loads have not reached the ocean. Post-land clearance increases in erosional flux from watersheds, and burial in estuaries are important processes that must be considered to calculate accurate global sediment and carbon budgets. ?? 2008 Coastal and Estuarine Research Federation.

  8. Heavy mineral analysis for assessing the provenance of sandy sediment in the San Francisco Bay Coastal System

    Science.gov (United States)

    Wong, F. L.; Woodrow, D. L.; McGann, M. L.

    2012-12-01

    Heavy minerals have been used to trace the sources and transportation of sandy sediment in San Francisco Bay and nearby coastal areas since the 1960s. We have the opportunity to sample similar environments and revisit the heavy mineral populations under the current San Francisco Coastal System study of the provenance of beach sand. Most of the sandy sediment in San Francisco Bay can be traced to distant sources including the Sierra Nevada batholith and associated terranes with local contributions from the Franciscan Complex. Heavy minerals from Sierran sources include ordinary hornblende, metamorphic amphiboles, and hypersthene while those from the Franciscan Complex include other types of pyroxene, epidote, basaltic hornblende, and glaucophane... Tertiary strata and volcanics in the surrounding hills and displaced Sierran rocks found on the continental shelf west of the San Andreas Fault Zone introduce similar minerals, but perhaps in a lesser volume to be identified as major contributors... The primary result of cluster analysis of heavy minerals separated from sand-sized sediment taken within San Francisco Bay, the adjacent continental shelf, local beaches, cliffs outside the Golden Gate, and upstream drainages indicate a widespread occurrence of sediment traceable to the Sierra Nevada. A second cluster of samples identifies samples of mixed Sierran and Franciscan lineage within the strait of the Golden Gate, on the San Francisco bar, and on coastal beaches. Sediment samples with predominantly Franciscan mineral content appear on beaches around Point Reyes, possibly transported from the Russian River. The heavy mineral composition supports transport from the east, through San Francisco Bay and out the Golden Gate to the San Francisco bar and southward.

  9. A comparison of acoustic and observed sediment classifications as predictor variables for modelling biotope distributions in Galway Bay, Ireland

    Science.gov (United States)

    O'Carroll, Jack P. J.; Kennedy, Robert; Ren, Lei; Nash, Stephen; Hartnett, Michael; Brown, Colin

    2017-10-01

    The INFOMAR (Integrated Mapping For the Sustainable Development of Ireland's Marine Resource) initiative has acoustically mapped and classified a significant proportion of Ireland's Exclusive Economic Zone (EEZ), and is likely to be an important tool in Ireland's efforts to meet the criteria of the MSFD. In this study, open source and relic data were used in combination with new grab survey data to model EUNIS level 4 biotope distributions in Galway Bay, Ireland. The correct prediction rates of two artificial neural networks (ANNs) were compared to assess the effectiveness of acoustic sediment classifications versus sediments that were visually classified by an expert in the field as predictor variables. To test for autocorrelation between predictor variables the RELATE routine with Spearman rank correlation method was used. Optimal models were derived by iteratively removing predictor variables and comparing the correct prediction rates of each model. The models with the highest correct prediction rates were chosen as optimal. The optimal models each used a combination of salinity (binary; 0 = polyhaline and 1 = euhaline), proximity to reef (binary; 0 = within 50 m and 1 = outside 50 m), depth (continuous; metres) and a sediment descriptor (acoustic or observed) as predictor variables. As the status of benthic habitats is required to be assessed under the MSFD the Ecological Status (ES) of the subtidal sediments of Galway Bay was also assessed using the Infaunal Quality Index. The ANN that used observed sediment classes as predictor variables could correctly predict the distribution of biotopes 67% of the time, compared to 63% for the ANN using acoustic sediment classes. Acoustic sediment ANN predictions were affected by local sediment heterogeneity, and the lack of a mixed sediment class. The all-round poor performance of ANNs is likely to be a result of the temporally variable and sparsely distributed data within the study area.

  10. Concentration, distribution, and bioavailability of mercury and methylmercury in sediments of Baltimore Harbor and Chesapeake Bay, Maryland, USA

    Energy Technology Data Exchange (ETDEWEB)

    Mason, R.P.; Lawrence, A.L.

    1999-11-01

    For the Chesapeake Bay, sediments in regions such as Baltimore Harbor have total mercury (Hg) concentrations that exceed environmental effects guidelines. However, fish concentrations do not appear elevated. Indeed, the factors controlling the transfer of sedimentary Hg, especially as monomethylmercury (MMHg), the most bioaccumulative form of Hg, to these aquatic organisms are poorly understood. To examine this, the authors have investigated the distribution and bioavailability of Hg and MMHg to benthic organisms in Baltimore harbor and the Chesapeake Bay, in Maryland, USA. The results discussed here show that sediment concentration for both total Hg and MMHg covaries with sediment organic content and that this parameter is a better predictor, for surface sediments, of concentration than iron content, acid volatile sulfide (AVS), or other factors. Furthermore, correlations between inorganic Hg and MMHg in benthic biota with sediment levels suggest that variation in the bioaccumulation factor (SBAF) for invertebrates is best explained in terms of sediment organic content. thus, the results from this study emphasize the importance of organic matter in regions removed from point source input in controlling both the concentration and bioavailability of MMHg to organisms. Because of the exponential nature of the SBAF/organic content relationship, there is a nonlinear organism response to MMHg in sediments that must be considered in any estimation of the toxic effect of sediment MMHg. Also, as a result of the decoupling between total Hg and MMHg concentration and bioavailability in surface sediments, any remediation evaluation of bioavailability and/or toxicity that is based only on total Hg concentration is unlikely to provide a reliable prediction.

  11. Levels of 137Cs in muddy sediments on the seabed in the Bay of Cadiz (Spain). Part II. Model of vertical migration of (137)Cs.

    Science.gov (United States)

    Ligero, R A; Barrera, M; Casas-Ruiz, M

    2005-01-01

    This second part of the study reports the development of a model to describe the vertical migration of the artificial radioisotope (137)Cs in the sediment column on the seabed of the Bay of Cadiz. The application of the model provides an overall picture of the process of sedimentation in the Inner Bay of Cadiz. The spatial distribution of the rate of sedimentation enables us to study the sources of sediments and the means by which the sediments have been transported. A method has been derived from the rate of sedimentation to perform the dating of the layers of sediment. The model describes the behaviour of (137)Cs in the area under study, taking into account the time of residence in the zones that are the source of accumulation, the origin of the sedimentary material, together with the diffusion of the radionuclide in the sediment of the seabed.

  12. Water Quality and Sedimentation Data of the Coastal Intensive Site Network (CISNet) Long Term Monitoring Sites in Kaneohe Bay, Oahu, Hawaii from 1998 to 2001 (NODC Accession 0001473)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A long term project to monitor water quality and sediment processes in Kaneohe Bay was initiated in November 1998 and continued through July 2001. Four primary sites...

  13. National Status and Trends: Bioeffects Program - Magnitude and Extent of Sediment Toxicity in Four Bays of the Florida Panhandle: Pensacola, Choctawhatchee, St. Andrew and Apalachicola

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The toxicity of sediments in Pensacola, Choctawhatchee, St. Andrew and Apalachicola Bays was determined as part of bioeffects assessments performed by NOAA's...

  14. Contaminant profiles for surface water, sediment, flora and fauna associated with the mangrove fringe along middle and lower East Tampa Bay

    Science.gov (United States)

    Contaminant concentrations are reported for surface water, sediment, seagrass, mangroves, Florida Crown conch, blue crabs and fish collected during 2010-2011 from the mangrove fringe along eastern Tampa Bay. Concentrations of trace metals, chlorinated pesticides, atrazine, total ...

  15. Effect of Coarse Particle Volume Fraction on the Yield Stress of Muddy Sediments from Marennes Oléron Bay

    Directory of Open Access Journals (Sweden)

    A. Pantet

    2010-01-01

    Full Text Available Coastal erosion results from a combination of various factors, both natural and humaninduced, which have different time and space patterns. In addition, uncertainties still remain about the interactions of the forcing agents, as well as on the significance of non-local causes of erosion. We focused about the surface sediments in the Marennes Oléron bay, after a general description of the site that has many various activities. The superficial sediments show a mechanical behavior, mainly depends on the fine fraction for a composition that contains up to 60% of sandy material. Fine sediments fraction has a typical yield stress depending naturally of concentration or water content. This yield could be modified slightly or significantly by adding silt or sand. As a result, the rheological measurement sensitivity allows us to characterize five typical sediments that correlate with solid fraction and fine fraction.

  16. Distribution of clay minerals in marine sediments off Chennai, Bay of Bengal, India:Indicators of sediment sources and transport processes

    Institute of Scientific and Technical Information of China (English)

    Subramanian VEERASINGAM; Ramdoss VENKATACHALAPATHY; Thirunavukkarasu RAMKUMAR

    2014-01-01

    Clay mineralogy, texture size and statistical analyses were carried out on surface sediments from the continental shelf of Chennai, Bay of Bengal, India. The purpose of this study is to characterize the clay mineral distribution and its relation to the hydrodynamics off Chennai to identify the sources and transport pathways of the marine sediments. Characterization of clay minerals in coastal sediments by Fourier Transform Infrared (FTIR) spectroscopy has provided the association of quartz, feldspar, kaolinite, chlorite, illite and iron oxides (magnetite and hematite) derived from river catchments and coastal erosion. Kaolinite, chlorite, illite, iron oxides, and organic matter are the dominant minerals in Cooum, and Adayar region. High quartz and feldspar zones were identified in Marina, which are being confined the sand zone and paralleling the coast. The strong relationships among the wave energy density, sand, quartz and carbonate revealed that wave induced littoral drift system play a dominant role in transportation and deposition of sediments in the Chennai coast. The sediment texture and minerals data are in agreement well with the previous results of hydrodynamics and littoral drift models in this region. Multivariate statistical analyses (correlation, cluster and factor analyses) were carried out and obtained results suggested that clay minerals and organic matter are trapped in silt and clay particles, whereas quartz, feldspar and carbonate are associated with sand particles. Results of sediment sources and transport processes from this study will be useful to predict the fate of the pollutants released from land or the potential change in sediment delivery to coastal areas.

  17. Influential factors on the exchange rate of dissolved inorganic nutrients at the sediment-water interface in Jiaozhou Bay, China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Incubation experiments are carried out to study the exchange rates of dissolved inorganic nutrients including silicate, phosphate, ammonium, nitrite, and nitrate (vSiO3-Si, vPO4-P, vNH4-N, vNO2-N and vNO3-N) at the sediment-water interface in the Jiaozhou Bay. Major factors influencing the exchange rates are discussed in detail, which include the dissolved inorganic nutrient concentrations in porewater (Cpw), water and clay contents,and grain size of the sediments (CH2O, Cclay and GSsed). The results may provide insight into the dynamics of nutrient transport and the environmental capacity of nutrients in Jiaozhou Bay, and should be beneficial to solving the problems caused by excessive nutrient input this area.

  18. Metal pollution status in Zhelin Bay surface sediments inferred from a sequential extraction technique, South China Sea.

    Science.gov (United States)

    Gu, Yang-Guang; Lin, Qin; Jiang, Shi-Jun; Wang, Zhao-Hui

    2014-04-15

    Surface sediments collected from Zhelin Bay, the largest mariculture base of eastern Guangdong Province, were analyzed for total metal concentrations and chemical speciation. The results demonstrated that the average total concentration (mg/kg) ranges were 36.7-65.8 (Pb), 53.8-98.8 (Cr), 39.0-87.1 (Ni), 50.9-144.5 (Cu), and 175.0-251.2 (Zn), which were clearly higher with respect to their corresponding benchmark values. The predominant speciation of Pb was reducible and comprised a residual fraction, whereas a major portion (57.6-95.4%) of Cr, Ni, Cu, and Zn was strongly associated with the residual fractions. Taking as a whole, surface sediments of Zhelin Bay had a 21% probability of toxicity based on the mean effects range-median quotient.

  19. [Heavy metals in the surface sediment of the dumping ground outside Jiaozhou Bay and their potential ecological risk].

    Science.gov (United States)

    Cao, Cong-hua; Zhang, Nai-xing; Wu, Feng-cong; Sun, Bin; Ren, Rong-zhu; Sun, Xu; Lin, Sen; Zhang, Shao-ping

    2011-05-01

    Based on the monitoring data of heavy metals (Cr, Hg, Cd, Pb, Zn, Cu) in the surface sediment of the dumping ground outside Jiaozhou Bay from 2003 to 2008, the distribution patterns, factors controlling the distribution, and the potential ecological risks of heavy metals were studied with the data in 2007-08, and the fluctuation trends of heavy metals in the surface sediment over the 6 years were also discussed. The average concentrations of heavy metals Cr, Hg, Cd, Pb, Zn, Cu in the surface sediment were 29.47, 0.065, 0.105, 1.145, 9.63, 3.355 microg/g, respectively. Except for Cr, the concentration of heavy metals was high in the central dumping area while low outside the dumping ground, suggesting that the dredged material dumped was the main source of heavy metals. Organic carbon content in the surface sediment had a significant positive correlation with heavy metals except for Cr. Based on the results of ecological risk assessment, Hg had a medium potential ecological risk, while the other heavy metals had low potential ecological risk. The overall risk index (RI) of the heavy metals was 100.50, which was considered as a level of low potential ecological risk. The average concentration of heavy metals showed a decreasing trend over the 6 years, except Hg. In conclusion, the quality of surface sediment in term of heavy metals in the dumping ground outside Jiaozhou Bay is relatively good.

  20. Metal pollution in a contaminated bay: relationship between metal geochemical fractionation in sediments and accumulation in a polychaete.

    Science.gov (United States)

    Fan, Wenhong; Xu, Zhizhen; Wang, Wen-Xiong

    2014-08-01

    Jinzhou Bay in Northern China has been seriously contaminated with metals due to the impacts of smelting activities. In this study, we investigated the relationship between metal accumulation in a deposit-feeding polychaete Neanthes japonica and metal concentration and geochemical fractionation (Cd, Cu, Pb, Zn and Ni) in sediments of Jinzhou Bay. Compared with the historical data, metals in the more mobile geochemical fraction (exchangeable and carbonate fractions) were gradually partitioned into the more stable fraction (Fe-Mn oxides) over time. Metal concentration and geochemical fractionation in sediment significantly affected metal bioavailability and accumulation in polychaetes, except for Ni. Metal accumulation in polychaetes was significantly influenced by Fe or Mn content, and to a lesser degree by organic matter. Prediction of metal bioaccumulation in polychaetes was greatly improved by normalizing metal concentrations to Mn content in sediment. The geochemical fractionation of metals in sediments including the exchangeable, organic matter and Fe-Mn oxides were important in controlling the sediment metal bioavailability to polychaetes.

  1. Biogeochemical study of water and bottom sediments from the Khai river - Nha Trang Bay estuarine system, South China Sea

    Science.gov (United States)

    Shulga, Natalia; Lobys, Nikolay; Drozdova, Anastasia; Peresypkin, Valery

    2014-05-01

    The present study was carried out in Nha Trang Bay (Southern Vietnam, the South China Sea). The samples of water, suspended matter and bottom sediments were collected in summer 2010-2012 in section from the estuary of the Khai River to the marine part of the bay. The samples were analyzed in the stationary lab of IO RAS, Moscow, by TOC-V-CPH, GC/MS and pirolysis methods. We report here the novel data on sources, transformation and burial of OM coming from the Khai river waters. The investigation is focused on ontent and distribution of suspended matter (SM) in the estuary, dissolved organic carbon (DOC), particulated organic carbon (POC); molecular and group composition of hydrocarbons (n-alkanes, steranes, hopanes) and mercury content in water, SM and bottom sediments. It was found that concentration of POC and SM decrease in the Nha Trang Bay waters from estuary to the open part of the bay. However, major changes in the concentration of SM and POC belong to the zone of salinity gradient.DOC behavior is more stable throughout the study area. Organic-geochemical indicators estimation allowed recognition of genesis and transformation degree of organic matter in the study area. The estuary is characterized by mixed genesis of SM with a predominance of allochthonous organic matter whereas outlying parts of the Nha Trang bay are characterized by autochthonous OM. Composition of OM in sediments reflects regularities identified above, despite of the interannual and seasonal variability in the study area. The investigation reveals a predominance of terrestrial organic matter in the silt sediments of the estuary, transported by the Khai river. Distribution of OM in sediments of marine part of the bay is mosaic, with a predominance of planktonogenic, bacterial or terrestrial input at their complex combination. Local anthropogenic pollution as well as an impact of industrial city effluents are found in river- and seaport areas. According to obtained data sedimentation rate

  2. Modeling bed-load transport of coarse sediments in the Great Bay Estuary, New Hampshire

    Science.gov (United States)

    Bilgili, A.; Swift, M. R.; Lynch, D. R.; Ip, J. T. C.

    2003-12-01

    Current, sea level and bed-load transport are investigated in the Lower Piscataqua River section of the Great Bay Estuary, New Hampshire, USA—a well-mixed and geometrically complex system with low freshwater input, having main channel tidal currents ranging between 0.5 and 2 m s -1. Current and sea level forced by the M 2M 4M 6 tides at the estuarine mouth are simulated by a vertically averaged, non-linear, time-stepping finite element model. The hydrodynamic model uses a fixed boundary computational domain and accounts for flooding-drying of tidal flats by making use of a groundwater component. Inertia terms are neglected in comparison with pressure gradient and bottom friction terms, which is consistent with the observed principal dynamic balance for this section of the system. The accuracy of hydrodynamic predictions in the study area is demonstrated by comparison with four tidal elevation stations and two cross-section averaged current measurements. Simulated current is then used to model bed-load transport in the vicinity of a rapidly growing shoal located in the main channel of the lower system. Consisting of coarse sand and gravel, the shoal must be dredged every five to eight years. Two approaches are taken—an Eulerian parametric method in which nodal bed-load flux vectors are averaged over the tidal cycle and a Lagrangian particle tracking approach in which a finite number of sediment particles are released and tracked. Both methods yield pathways and accumulations in agreement with the observed shoal formation and the long-term rate of sediment accumulation in the shoal area.

  3. Sediment profile image data from October 1999 in Apalachicola Bay, Florida

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Apalachicola Bay National Estuarine Research Reserve and the NOAA Office for Coastal Management worked together to map benthic habitats within Apalachicola Bay,...

  4. Bioavailability of heavy metals in water and sediments from a typical Mediterranean Bay (Málaga Bay, Region of Andalucía, Southern Spain).

    Science.gov (United States)

    Alonso Castillo, M L; Sánchez Trujillo, I; Vereda Alonso, E; García de Torres, A; Cano Pavón, J M

    2013-11-15

    Concentrations of heavy metals were measured in sediment and water from Málaga Bay (South Spain). In the later twentieth century, cities such as Málaga, have suffered the impact of mass summer tourism. The ancient industrial activities, and the actual urbanization and coastal development, recreation and tourism, wastewaters treatment facilities, have been sources of marine pollution. In sediments, Ni was the most disturbing metal because Ni concentrations exceeded the effects range low (ERL), concentration at which toxicity could start to be observed in 85% of the samples analyzed. The metal bioavailability decreased in the order: Cd>Ni>Pb>Cu>Cr. In the sea water samples, Cd and Pb were the most disturbing metals because they exceeded the continuous criteria concentration (CCC) of US EPA in a 22.5% and 10.0% of the samples, respectively. Statistical analyses (ANOVA, PCA, CA) were performed. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Surface (sea floor) and near-surface (box cores) sediment mineralogy in Baffin Bay as a key to sediment provenance and ice sheet variations

    Science.gov (United States)

    Andrews, John T.; Eberl, D.D.

    2011-01-01

    To better understand the glacial history of the ice sheets surrounding Baffin Bay and to provide information on sediment pathways, samples from 82 seafloor grabs and core tops, and from seven box cores were subjected to quantitative X-ray diffraction weight percent (wt.%) analysis of the 2000 m) all show an abrupt drop in calcite wt.% (post-5 cal ka BP?) following a major peak in detrital carbonate (mainly dolomite). This dolomite-rich detrital carbonate (DC) event in JR175BC06 is possibly coeval with the Younger Dryas cold event. Four possible glacial-sourced end members were employed in a compositional unmixing algorithm to gain insight into down core changes in sediment provenance at the deep central basin. Estimates of the rates of sediment accumulation in the central basin are only in the range of 2 to 4 cm/cal ka, surprisingly low given the glaciated nature of the surrounding land.

  6. Diversity of mercury resistance determinants among Bacillus strains isolated from sediment of Minamata Bay.

    Science.gov (United States)

    Narita, Masaru; Chiba, Kazuyuki; Nishizawa, Hiroshi; Ishii, Hidenori; Huang, Chieh-Chen; Kawabata, Zen'ichiro; Silver, Simon; Endo, Ginro

    2003-06-06

    Thirty mercury-resistant (Hg R) Bacillus strains were isolated from mercury-polluted sediment of Minamata Bay, Japan. Mercury resistance phenotypes were classified into broad-spectrum (resistant to inorganic Hg(2+) and organomercurials) and narrow-spectrum (resistant to inorganic Hg(2+) and sensitive to organomercurials) groups. Polymerase chain reaction (PCR) product sizes and the restriction nuclease site maps of mer operon regions from all broad-spectrum Hg R Bacillus were identical to that of Bacillus megaterium MB1. On the other hand, the PCR products of the targeted merP (extracellular mercury-binding protein gene) and merA (intracellular mercury reductase protein gene) regions from the narrow-spectrum Hg R Bacillus were generally smaller than those of the B. megaterium MB1 mer determinant. Diversity of gene structure configurations was also observed by restriction fragment length polymorphism (RFLP) profiles of the merA PCR products from the narrow-spectrum Hg R Bacillus. The genetic diversity of narrow-spectrum mer operons was greater than that of broad-spectrum ones.

  7. Speciation, distribution, and potential ecological risk assessment of heavy metals in Xiamen Bay surface sediment

    Institute of Scientific and Technical Information of China (English)

    LIN Cai; LIU Yang; LI Wenquan; SUN Xiuwu; JI Weidong

    2014-01-01

    Based on the survey of surface sediment in Xiamen Bay in October 2011, the speciation, distribution, and potential ecological risk assessment of heavy metals (Cu, Pb, Zn, Cd, and Cr) in this area were studied us-ing the sequential extraction method and ecological risk assessment method. The results indicated:(1) the total concentrations of these heavy metals were influenced by runoff, industrial wastewater, and sewage, and were all higher in the coastal area than the offshore area while the highest area of Pb was a little far-ther away from the coastal water due to atmosphere deposition;(2) sequential extractions suggested that Cu was mainly composed with residual and Fe/Mn-oxide bound fractions, Pb was bound to Fe/Mn-oxide, Zn and Cr were dominated by residual, and Cd bound to exchangeable and carbonate fractions; (3) the order of migration and transformation sequence was Cd>Pb>Cu>Zn>Cr and the degree of pollution was Cd>Pb>Cu>Zn>Cr;and (4) the ratios of the secondary and primary phases showed that Zn and Cr were both clean, Cu may be polluted, Pb was moderately polluted, while Cd was heavily polluted.

  8. [Microbial sulfate reduction in sediments of the coastal zone and littoral of the Kandalaksha bay of the White sea].

    Science.gov (United States)

    Savvichev, A S; Rusanov, I I; Iusupov, S K; Baĭramov, I T; Pimenov, N V; Lein, A Iu; Ivanov, M V

    2003-01-01

    Microbiological and biogeochemical investigations of the coastal zone and the littoral of the Kandalaksha Bay of the White Sea were carried out. The material for investigations was obtained in the series of expeditions of the Institute of Microbiology, Russian Academy of Sciences, in August 1999, 2000, 2001, and in March 2003. The studies were conducted on the littoral and in the water area of the Kandalaksha Preserve, the Moscow University Belomorsk Biological Station, and the Zoological Institute Biological Station, Russian Academy of Sciences, Sediment sampling on the littoral was carried out in the typical microlandscapes differing in the sediment properties and macrobenthos distribution. The maximal sulfate reduction rate (SRR) was shown for the shallow part of the Chemorechenskaya Bay (up to 2550 micrograms S/(dm3 day)) and in the Bab'ye More Bay (up to 3191 micrograms S/(dm3 day)). During the winter season, at a temperature of -0.5-0.5 degrees C, the SRR in the sediments of the Kartesh Bay was 7.9-13 micrograms S/(dm3 day). In the widest limits, the SRR values varied in the sediment cores sampled on the littoral. The minimal values (11 mu]g S/(dm3 day)) were obtained in the core samples on the silt-sandy littoral. The littoral finely dispersed sediments rich in organic matter were characterized by high SRR values (524-1413 micrograms S/(dm3 day)). The maximal SRR values were shown for the sediments present within the stretch of decomposing macrophytes, in local pits at the lower littoral waterline, and in the mouth of a freshwater stream (51-159 mg S/(dm3 day)). A sharp difference in the level of H2S production in the type microlandscapes was shown. The average hydrogen sulfide production in finely dispersed sediments constituted 125 mg S/(m2 day); in stormy discharge deposits, 1950 mg S/(m2 day); in depressions under stones and in silted pits, 4300 mg S/(m2 day). A calculation made with regard to the area of microlandscapes with increased productivity shows

  9. Application of {sup 137}Cs and {sup 210}Pb radionuclides to determine sedimentation rates of recent sediments from Admiralty Bay, Antarctica Peninsula

    Energy Technology Data Exchange (ETDEWEB)

    Nascimento, Mylene Giseli do; Martins, Cesar de Castro [Universidade Federal do Parana (UFPR), Pontal do Parana, PR (Brazil). Centro de Estudos do Mar (CEM); Figueira, Rubens C.L.; Montone, Rosalinda C.; Mahiques, Michel M. de; Tessler, Moyses G., E-mail: rfigueira@usp.b [Universidade de Sao Paulo (USP), SP (Brazil). Inst. Oceanografico. Dept. de Oceanografia Fisica, Quimica e Geologica; Vendrame, Antonio C. [Universidade Cruzeiro do Sul, Sao Paulo, SP (Brazil)

    2009-07-01

    Studies about natural and artificial radionuclides in areas such as the Antarctic are key to understand natural and dynamic processes in marine environments. These studies are important to determine levels of radioactive elements and local sedimentation rates. Five marine sediment cores were collected in different points of Admiralty Bay, in the Antarctic Peninsula. The purpose of this study was to determine {sup 137}Cs, {sup 226}Ra and {sup 210}Pb and sedimentation rates at each site. {sup 137}Cs, {sup 210}Pb and {sup 226}Ra were assayed by gamma-counting through direct measurement of the peak at 661 keV, 47 keV and 609 keV, respectively. Sedimentation rates were obtained by {sup 137}Cs and {sup 210}Pb (CIC and CRS). The activities for {sup 137}Cs ranged from 0.84 to 7.09 Bq kg{sup -1}; to {sup 226}Ra from 6.77 to 31.07 Bq kg{sup -1} for {sup 210}Pb ranged from 1.10 to 36.90 Bq kg{sup -1}. The sedimentation rates obtained by the three models ranged from 0.11+-0.01 cm y{sup -1} to 0.46+-0.05 cm y{sup -1}. The levels of {sup 137}Cs registered in this study, as well as in other studies in the Antarctic region indicate that global fallout is the main cause of artificial radionuclides present in this environment, since the Antarctic has not suffered a direct action of human activities that released radioactive elements. The possible grain size variations that occur in the studied points of Admiralty Bay may explain the differences found in the vertical distribution of radionuclides, because of the different values of sedimentation rates and respective dating determined in their profiles. (author)

  10. Rapid sedimentation of iron oxyhydroxides in an active hydrothermal shallow semi-enclosed bay at Satsuma Iwo-Jima Island, Kagoshima, Japan

    Science.gov (United States)

    Kiyokawa, Shoichi; Ueshiba, Takuya

    2015-04-01

    Hydrothermal activity is common in the fishing port of Nagahama Bay, a small semi-enclosed bay located on the southwest coast of Satsuma Iwo-Jima Island (38 km south of Kyushu Island, Japan). The bay contains red-brown iron oxyhydroxides and thick deposits of sediment. In this work, the high concentration and sedimentation rates of oxyhydroxide in this bay were studied and the sedimentary history was reconstructed. Since dredging work in 1998, a thickness of 1.0-1.5 m of iron oxyhydroxide-rich sediments has accumulated on the floor of the bay. To estimate the volume of iron oxyhydroxide sediments and the amount discharged from hydrothermal vents, sediment traps were operated for several years and 13 sedimentary core samples were collected to reconstruct the 10-year sedimentary history of Nagahama Bay. To confirm the timing of sedimentary events, the core data were compared with meteorological records obtained on the island, and the ages of characteristic key beds were thus identified. The sedimentation rate of iron oxyhydroxide mud was calculated, after correcting for sediment input from other sources. The sediments in the 13 cores from Nagahama Bay consist mainly of iron oxyhydroxide mud, three thick tephra beds, and a topmost thick sandy mud bed. Heavy rainfall events in 2000, 2001, 2002, and 2004-2005 coincide with tephra beds, which were reworked from Iwo-Dake ash deposits to form tephra-rich sediment. Strong typhoon events with gigantic waves transported outer-ocean-floor sediments and supplied quartz, cristobalite, tridymite, and albite sands to Nagahama Bay. These materials were redeposited together with bay sediments as the sandy mud bed. Based on the results from the sediment traps and cores, it is estimated that the iron oxyhydroxide mud accumulated in the bay at the relatively rapid rate of 33.3 cm/year (from traps) and 2.8-4.9 cm/year (from cores). The pore water contents within the sediment trap and core sediments are 73%-82% and 47%-67%, respectively

  11. Distribution and generic composition of culturable marine actinomycetes from the sediments of Indian continental slope of Bay of Bengal

    Science.gov (United States)

    Das, Surajit; Lyla, P. S.; Ajmal Khan, S.

    2008-05-01

    Actinomycetes population from continental slope sediment of the Bay of Bengal was studied. Samples were collected during two voyages of FORV Sagar Sampada in 2004 (May-June) and 2005 (July) respectively from 11 transects (each transect had ca. 200 m, 500 m, and 1 000 m depth stations). The physicochemical parameters of overlying water, and sediment samples were also recorded. The actinomycete population ranged from 5.17 to 51.94 CFU/g dry sediment weight and 9.38 to 45.22 CFU/g dry sediment weight during the two cruises respectively. No actinomycete colony was isolated from stations in 1 000 m depth. Two-way analysis of variance showed significant variation among stations (ANOVA two-way, P0.05). Three actinomycetes genera were identified. Streptomyces was found to be the dominating one in both the cruises, followed by Micromonospora, and Actinomyces. The spore of Streptomyces isolates showed the abundance in spiral spore chain. Spore surface was smooth. Multiple regression analysis revealed that the influencing physico-chemical factors were sediment pH, sediment temperature, TOC, porosity, salinity, and pressure. The media used in the present study was prepared with seawater. Thus, they may represent an autochthonous marine flora and deny the theory of land runoff carriage into the sea for adaptation to the salinity of the seawater and sediments.

  12. Concentration of Antifouling Biocides and Metals in Sediment Core Samples in the Northern Part of Hiroshima Bay

    Directory of Open Access Journals (Sweden)

    Noritaka Tsunemasa

    2014-06-01

    Full Text Available Accumulation of Ot alternative antifoulants in sediment is the focus of this research. Much research had been done on surface sediment, but in this report, the accumulation in the sediment core was studied. The Ot alternative antifoulants, Diuron, Sea-Nine211, and Irgarol 1051, and the latter’s degradation product, M1, were investigated in five samples from the northern part of Hiroshima Bay. Ot compounds (tributyltin (TBT and triphenyltin (TPT were also investigated for comparison. In addition, metal (Pb, Cu, Zn, Fe and Mn levels and chronology were measured to better understand what happens after accumulation on the sea floor. It was discovered that Ot alternative antifoulant accumulation characteristics in sediment were like Ot compounds, with the concentration in the sediment core being much higher than surface sediment. The concentration in sediment seems to have been affected by the regulation of Ot compounds in 1990, due to the concentration of Ot alternative antifoulants and Ot compounds at the survey point in front of the dock, showing an increase from almost the same layer after the regulation.

  13. The South Carolina Coastal Erosion Study: Numerical modeling of circulation and sediment transport in Long Bay, SC

    Science.gov (United States)

    Warner, J. C.; Sullivan, C.; Voulgaris, G.; Work, P.; Haas, K.; Hanes, D. M.

    2004-12-01

    Long Bay, South Carolina, is a heavily populated coastal region that supports a large tourism industry. Sand resources are important for both recreation and coastal habitat. Earlier geological framework studies have identified a large sand deposit oblique to the shoreline, oriented clockwise in the offshore direction. This sand feature is ~ 10 km long, 2 km wide, and in excess of 3m thick, possibly providing a source for beach nourishment material. Objectives of this study are to describe the physical processes that control the transport of sediment in Long Bay, specifically off the coast of Myrtle Beach, South Carolina. Specifically we seek to 1) measure and model the oceanographic circulation in the region, 2) identify the processes that maintain the presence of the offshore sand feature, 3) quantify the control that the shoal exerts on the nearshore through changes in wave energy propagation, and 4) identify consequences of removal of the offshore sand feature. Both observational and numerical experiments are used to study the oceanographic circulation and transport of sediment. The observational study is described in an accompanying poster and consists of eight sites that measured tides, surface waves, currents, salinity, temperature, suspended sediment concentrations, and bed forms from October 2003 to April 2004. Numerical modeling for circulation and sediment transport in the study region uses a new version of ROMS (v2.1) that now includes transport of multiple grain sizes, coupling of sediment transport to wave bottom boundary layer models, and evolution of the bottom morphology. The SWAN model is used to compute wave propagation. Results indicate that currents in the study area are strongly influenced by both tidal motion and wind driven setup / setdown. The presence of the offshore sand feature alters the residual flows in the region. Sediment transport is more significant during periods of sustained strong winds that generate local waves. Wind direction

  14. The deep biosphere in terrestrial sediments in the Chesapeake Bay area, Virginia, USA

    Directory of Open Access Journals (Sweden)

    Anja eBreuker

    2011-07-01

    Full Text Available For the first time quantitative data on the abundance of Bacteria, Archaea and Eukarya in deep terrestrial sediments are provided using multiple methods (total cell counting, quantitative real-time PCR (Q-PCR and catalyzed reporter deposition – fluorescence in situ hybridization (CARD-FISH. The oligotrophic (organic carbon content of ~ 0.2 % deep terrestrial sediments in the Chesapeake Bay area at Eyreville, Virginia, USA, were drilled and sampled up to a depth of 140 m in 2006. The possibility of contamination during drilling was checked using fluorescent microspheres. Total cell counts decreased from 109 to 106 cells per g dry weight (dw within the uppermost 20 m depth, and did not further decrease with depth below. A significant proportion of the total cell counts could be detected with CARD-FISH within the uppermost 7 m depth. The CARD-FISH numbers for Bacteria were about an order of magnitude higher than those for Archaea. The dominance of Bacteria over Archaea was confirmed by Q-PCR. The down core quantitative distribution of prokaryotic and eukaryotic small subunit ribosomal RNA genes as well as functional genes involved in different biogeochemical processes was revealed by Q-PCR for the uppermost 10 m and for 80-140 m depth. Eukarya and the Fe(III- and Mn(IV-reducing bacterial group Geobacteriaceae were almost only found in the uppermost meter (arable soil, where reactive iron was detected in higher amounts. The bacterial candidate division JS-1 and the classes Anaerolineae and Caldilineae of the phylum Chloroflexi, highly abundant in marine sediments, were found up to the maximum sampling depth in high copy numbers at this terrestrial site as well. A similar high abundance of the functional gene cbbL encoding for the large subunit of RubisCO suggests that autotrophic microorganisms could be relevant in addition to heterotrophs. The functional gene aprA of sulfate reducing bacteria was found within distinct layers up to ca. 100 m depth

  15. The deep biosphere in terrestrial sediments in the chesapeake bay area, virginia, USA.

    Science.gov (United States)

    Breuker, Anja; Köweker, Gerrit; Blazejak, Anna; Schippers, Axel

    2011-01-01

    For the first time quantitative data on the abundance of Bacteria, Archaea, and Eukarya in deep terrestrial sediments are provided using multiple methods (total cell counting, quantitative real-time PCR, Q-PCR and catalyzed reporter deposition-fluorescence in situ hybridization, CARD-FISH). The oligotrophic (organic carbon content of ∼0.2%) deep terrestrial sediments in the Chesapeake Bay area at Eyreville, Virginia, USA, were drilled and sampled up to a depth of 140 m in 2006. The possibility of contamination during drilling was checked using fluorescent microspheres. Total cell counts decreased from 10(9) to 10(6) cells/g dry weight within the uppermost 20 m, and did not further decrease with depth below. Within the top 7 m, a significant proportion of the total cell counts could be detected with CARD-FISH. The CARD-FISH numbers for Bacteria were about an order of magnitude higher than those for Archaea. The dominance of Bacteria over Archaea was confirmed by Q-PCR. The down core quantitative distribution of prokaryotic and eukaryotic small subunit ribosomal RNA genes as well as functional genes involved in different biogeochemical processes was revealed by Q-PCR for the uppermost 10 m and for 80-140 m depth. Eukarya and the Fe(III)- and Mn(IV)-reducing bacterial group Geobacteriaceae were almost exclusively found in the uppermost meter (arable soil), where reactive iron was detected in higher amounts. The bacterial candidate division JS-1 and the classes Anaerolineae and Caldilineae of the phylum Chloroflexi, highly abundant in marine sediments, were found up to the maximum sampling depth in high copy numbers at this terrestrial site as well. A similar high abundance of the functional gene cbbL encoding for the large subunit of RubisCO suggests that autotrophic microorganisms could be relevant in addition to heterotrophs. The functional gene aprA of sulfate reducing bacteria was found within distinct layers up to ca. 100 m depth in low copy numbers

  16. How can climate change and engineered water conveyance affect sediment dynamics in the San Francisco Bay-Delta system?

    Science.gov (United States)

    Achete, Fernanda; Van der Wegen, Mick; Roelvink, Jan Adriaan; Jaffe, Bruce E.

    2017-01-01

    Suspended sediment concentration is an important estuarine health indicator. Estuarine ecosystems rely on the maintenance of habitat conditions, which are changing due to direct human impact and climate change. This study aims to evaluate the impact of climate change relative to engineering measures on estuarine fine sediment dynamics and sediment budgets. We use the highly engineered San Francisco Bay-Delta system as a case study. We apply a process-based modeling approach (Delft3D-FM) to assess the changes in hydrodynamics and sediment dynamics resulting from climate change and engineering scenarios. The scenarios consider a direct human impact (shift in water pumping location), climate change (sea level rise and suspended sediment concentration decrease), and abrupt disasters (island flooding, possibly as the results of an earthquake). Levee failure has the largest impact on the hydrodynamics of the system. Reduction in sediment input from the watershed has the greatest impact on turbidity levels, which are key to primary production and define habitat conditions for endemic species. Sea level rise leads to more sediment suspension and a net sediment export if little room for accommodation is left in the system due to continuous engineering works. Mitigation measures like levee reinforcement are effective for addressing direct human impacts, but less effective for a persistent, widespread, and increasing threat like sea level rise. Progressive adaptive mitigation measures to the changes in sediment and flow dynamics resulting from sea level rise may be a more effective strategy. Our approach shows that a validated process-based model is a useful tool to address long-term (decades to centuries) changes in sediment dynamics in highly engineered estuarine systems. In addition, our modeling approach provides a useful basis for long-term, process-based studies addressing ecosystem dynamics and health.

  17. Potential sources of hydrogel stabilization of Florida Bay lime mud sediments and implications for organic matter preservation

    Science.gov (United States)

    Louda, J.W.; Loitz, J.W.; Melisiotis, A.; Orem, W.H.

    2004-01-01

    The fine grained carbonate mud sediments of central Florida Bay are resuspended quite easily. However, this disturbance is usually limited to the surficial ('floc') layer, as the underlying sediments appear to be stabilized by an hydrogelation involving the bulk organic matter. That gelation has occurred within these sediments is suggested from their physical behavior and an observed mathematical relationship between the percentages of organic carbon (C org) and water. Specifically, when extruded from a core barrel, the sediment maintains its integrity and has the consistency of a fine spackling compound. However, upon homogenization, as with a stirring rod prior to sieving, these sediments break into two distinct phases, 1/2-2/3 milky water and 1/3-1/2 sediment grains, by volume. The relationship observed between Corg and water was modeled as both linear (% water = (0.0777) Corg + 0.2984, R2 = 0.8664) and logarithmic (% water = 0.2489 Ln Corg + 0.2842, R2 = 0.9455) functions. As this relationship tends to be asymptotic at higher Corg (>3.5% dry)/water values (>60%) and given an higher correlation, the relationship appears better modeled as a logarithmic function. Values of C org from 1.2 to over 6.5%dry wt. and water contents from 30 to over 70%wt. were observed. The calculated intercept revealed that, without organic carbon (viz. hydrogel formation), these carbonates would likely contain only ???30% water by weight ('m' from linear model). This gelation is proposed to involve exopolymeric substances (EPS), likely polysaccharides, derived from diatoms and cyanobacteria of the microphytobenthos. A cyanobacterial-diatomaceous biofilm/mat underlain by purple sulfur bacteria was shown, by pigment based chemotaxonomy, to form the main components of the microphytobenthos. Additional water column detrital biomass, also mainly cyanobacteria and diatoms, is admixed with the living microphytobenthos in a flocculent/nephloid layer above the sediments prior to final

  18. Isolation of enteroviruses from water, suspended solids, and sediments from Galveston Bay: survival of poliovirus and rotavirus adsorbed to sediments.

    OpenAIRE

    Rao, V. C.; Seidel, K M; Goyal, S M; Metcalf, T. G.; Melnick, J L

    1984-01-01

    The distribution and quantitation of enteroviruses among water, suspended solids, and compact sediments in a polluted estuary are described. Samples were collected sequentially from water, suspended solids, fluffy sediments (uppermost layer of bottom sediments), and compact sediment. A total of 103 samples were examined of which 27 (26%) were positive for virus. Polioviruses were recovered most often, followed by coxsackie B viruses and echoviruses 7 and 29. Virus was found most often attache...

  19. Radiolarian fluxes from the southern Bay of Bengal: sediment trap results

    Digital Repository Service at National Institute of Oceanography (India)

    Gupta, S.M.; Mohan, R.; Guptha, M.V.S.

    ., Actinom- 55 margin; Johnson and Nigrini, 1980), Chile (Molina mids, Disolenia quadrata, Didymocyrtis tetrathala- 9 Cruz, 1977) and the Benguela Current (Boltovskoy mus tetrathalamus, Tetrapyle octacantha, 57 et al., 1996).Thes e species may also...

  20. Environmental implications of the use of sulfidic back-bay sediments for dune reconstruction — Lessons learned post Hurricane Sandy

    Science.gov (United States)

    Plumlee, Geoffrey S.; Benzel, William M.; Hoefen, Todd M.; Hageman, Philip L.; Morman, Suzette A.; Reilly, Timothy J.; Adams, Monique; Berry, Cyrus J.; Fischer, Jeffrey; Fisher, Irene

    2016-01-01

    Some barrier-island dunes damaged or destroyed by Hurricane Sandy's storm surges in October 2012 have been reconstructed using sediments dredged from back bays. These sand-, clay-, and iron sulfide-rich sediments were used to make berm-like cores for the reconstructed dunes, which were then covered by beach sand. In November 2013, we sampled and analyzed partially weathered materials collected from the cores of reconstructed dunes. There are generally low levels of metal toxicants in the reconstructed dune materials. However oxidation of reactive iron sulfides by percolating rainwater produces acid-sulfate pore waters, which evaporate during dry periods to produce efflorescent gypsum and sodium jarosite salts. The results suggest use of sulfidic sediments in dune reconstruction has both drawbacks (e.g., potential to generate acid runoff from dune cores following rainfall, enhanced corrosion of steel bulwarks) and possible benefits (e.g., efflorescent salts may enhance structural integrity).

  1. Environmental implications of the use of sulfidic back-bay sediments for dune reconstruction - Lessons learned post Hurricane Sandy.

    Science.gov (United States)

    Plumlee, Geoffrey S; Benzel, William M; Hoefen, Todd M; Hageman, Philip L; Morman, Suzette A; Reilly, Timothy J; Adams, Monique; Berry, Cyrus J; Fischer, Jeffrey M; Fisher, Irene

    2016-06-30

    Some barrier-island dunes damaged or destroyed by Hurricane Sandy's storm surges in October 2012 have been reconstructed using sediments dredged from back bays. These sand-, clay-, and iron sulfide-rich sediments were used to make berm-like cores for the reconstructed dunes, which were then covered by beach sand. In November 2013, we sampled and analyzed partially weathered materials collected from the cores of reconstructed dunes. There are generally low levels of metal toxicants in the reconstructed dune materials. However oxidation of reactive iron sulfides by percolating rainwater produces acid-sulfate pore waters, which evaporate during dry periods to produce efflorescent gypsum and sodium jarosite salts. The results suggest use of sulfidic sediments in dune reconstruction has both drawbacks (e.g., potential to generate acid runoff from dune cores following rainfall, enhanced corrosion of steel bulwarks) and possible benefits (e.g., efflorescent salts may enhance structural integrity).

  2. Polybrominated diphenyl ethers (PBDEs) and alternative brominated flame retardants (aBFRs) in sediments from four bays of the Yellow Sea, North China.

    Science.gov (United States)

    Zhen, Xiaomei; Tang, Jianhui; Xie, Zhiyong; Wang, Runmei; Huang, Guopei; Zheng, Qian; Zhang, Kai; Sun, Yongge; Tian, Chongguo; Pan, Xiaohui; Li, Jun; Zhang, Gan

    2016-06-01

    The distribution characteristics and potential sources of polybrominated diphenyl ethers (PBDEs) and alternative brominated flame retardants (aBFRs) were investigated in 54 surface sediment samples from four bays (Taozi Bay, Sishili Bay, Dalian Bay, and Jiaozhou Bay) of North China's Yellow Sea. Of the 54 samples studied, 51 were collected from within the four bays and 3 were from rivers emptying into Jiaozhou Bay. Decabromodiphenylethane (DBDPE) was the predominant flame retardant found, and concentration ranged from 0.16 to 39.7 ng g(-1) dw and 1.13-49.9 ng g(-1) dw in coastal and riverine sediments, respectively; these levels were followed by those of BDE 209, and its concentrations ranged from n.d. to 10.2 ng g(-1) dw and 0.05-7.82 ng g(-1) dw in coastal and riverine sediments, respectively. The levels of DBDPE exceeded those of decabromodiphenyl ether (BDE 209) in most of the samples in the study region, whereas the ratio of DBDPE/BDE 209 varied among the four bays. This is indicative of different usage patterns of brominated flame retardants (BFRs) and also different hydrodynamic conditions among these bay areas. The spatial distribution and composition profile analysis indicated that BFRs in Jiaozhou Bay and Dalian Bay were mainly from local sources, whereas transport from Laizhou Bay by coastal currents was the major source of BFRs in Taozi Bay and Sishili Bay. Both the ∑PBDEs and ∑aBFRs (sum of pentabromotoluene (PBT), 2,3-diphenylpropyl-2,4,6-tribromophenyl ether (DPTE), pentabromoethylbenzene (PBEB), and hexabromobenzene (HBB)) were at low concentrations in all the sediments. This is probably attributable to a combination of factors such as low regional usage of these products, atmospheric deposition patterns, coastal currents transportation patterns, and degradation processes for higher BDE congeners. This paper is the first study that has investigated the levels of DBDPE in the coastal sediments of China's Yellow Sea.

  3. Mineral deposits and Cu-Zn-As dispersion-contamination in stream sediments from the semiarid Coquimbo Region, Chile

    Science.gov (United States)

    Oyarzun, R.; Oyarzún, J.; Lillo, J.; Maturana, H.; Higueras, P.

    2007-10-01

    This paper presents Cu-Zn-As geochemical data from stream sediment surveys carried out in the three main watersheds of the Coquimbo Region of Chile. This mountainous semiarid realm occupies an area of 40,656 km2 between 29° and 32°S. Given that the area has a long historical record of mining activities, important environmental disturbances were expected. However, despite the detection of three major geochemical anomalies for Cu, Zn, or As, only one can be unmistakably linked to the development of mining-metal recovery procedures (Andacollo-Panulcillo). An investigation of the other two anomalies (Elqui and Hurtado) reveals three major causes that fully or partially account for them: (1) the type of ore deposit and associated hydrothermal alteration; (2) the regional structural setting (intensity of fracturing); and (3) climate-landscape. Cu-Au-As epithermal deposits/prospects along the so-called El Indio belt are here regarded as the sources of both the Elqui and Hurtado anomalies. The strong advanced argillic alteration present in some of the epithermal deposits/prospects of the El Indio belt may have induced the loss of the buffering capacity of rocks, and therefore favoured metal dispersion during later oxidation-leaching of sulphides. This applies to the Elqui and Hurtado anomalies. Conversely, given that the potassic, propylitic and phyllic alterations do not affect the buffering capacity of rocks, only minor metal dispersion is observed in relation to the Los Pelambres porphyry copper deposit. Besides, the epithermal belt is located within a highly fractured Andean domain (3,000-4,000 m of altitude), which may have conditioned the fast unroofing of ore deposits, contributed to enhanced circulation of meteoric waters, and eventually, to strong oxidation, and leaching of metals. Metal dispersion is aggravated during rainy years in response to strong El Niño episodes.

  4. Features of distribution and quality of organic matter in the bottom sediments of the Great Peter Bay (Sea of Japan)

    Science.gov (United States)

    Nesterova, Olga; Tregubova, Valentina; Semal, Victoria; Vasenev, Ivan

    2017-04-01

    The nature and distribution of organic carbon in marine waters depends on: 1) biological productivity and revenue of the autochthonous organic matter to the bottom; 2) sediment grain-size composition and conditions of dumping, which in turn depends of hydrothermic regime, topography, speed River mist and received major erosion products; 3) living conditions of the benthos (the quantity consumed of OM, gas regime of habitats, physiological capacity of heterotrophs). Autochthonous OM of phytoplankton plays a dominant role in the processes of formation of humus in aquatic conditions. Bottom sediments at different distance from the shoreline to depths from 0.5 up to 480 m of the Sea of Japan, which are formed in various conditions of facies, were selected as the objects of study. There is no clear relationships to the amount of organic matter in bottom sediments on the characteristics of the distribution and nature of living matter in the oceans and seas. This is because the process of sedimentation and fossilization of organic matter on the seabed and the ocean floor depends on many factors (currents, depth). Humus of studied bottom sediments in composition can be attributed mainly to the humic type. Nonhydrolyzing rest is 70-90%. This is characteristic of bottom sediments formed in facial types of small bays, internal coastal shelf bights and the underwater slope. At a fraction of the carbon of humic acids in organic matter, ranging from 4 to 80% of the amount of humic and fulvic acids. Fulvic acids content is much less. This is due to more favourable conservation situation of humic acids in precipitation with high content of organic matter, whereas fulvic acids in aquatic environments are more labile and almost not dumped. Despite the fact humic acids are not the most stable component (s), however, with increased content of humic acids, the mobility of organic matter and removing it from the bottom sediments are reduced. Internal shelf facies of the Great Peter Bay

  5. Sediment and Vegetation as Reservoirs of Vibrio vulnificus in the Tampa Bay Estuary and Gulf of Mexico

    Science.gov (United States)

    Chase, Eva; Young, Suzanne

    2015-01-01

    The opportunistic pathogen Vibrio vulnificus occurs naturally in estuarine habitats and is readily cultured from water and oysters under warm conditions but infrequently at ambient conditions of <15°C. The presence of V. vulnificus in other habitats, such as sediments and aquatic vegetation, has been explored much less frequently. This study investigated the ecology of V. vulnificus in water by culture and quantitative PCR (qPCR) and in sediment, oysters, and aquatic vegetation by culture. V. vulnificus samples were taken from five sites around Tampa Bay, FL. Levels determined by qPCR and culture were significantly correlated (P = 0.0006; r = 0.352); however, V. vulnificus was detected significantly more frequently by qPCR (85% of all samples) compared to culture (43%). Culturable V. vulnificus bacteria were recovered most frequently from oyster samples (70%), followed by vegetation and sediment (∼50%) and water (43%). Water temperature, which ranged from 18.5 to 33.4°C, was positively correlated with V. vulnificus concentrations in all matrices but sediments. Salinity, which ranged from 1 to 35 ppt, was negatively correlated with V. vulnificus levels in water and sediments but not in other matrices. Significant interaction effects between matrix and temperature support the hypothesis that temperature affects V. vulnificus concentrations differently in different matrices and that sediment habitats may serve as seasonal reservoirs for V. vulnificus. V. vulnificus levels in vegetation have not been previously measured and reveal an additional habitat for this autochthonous estuarine bacterium. PMID:25636843

  6. Reconstruction of metal pollution and recent sedimentation processes in Havana Bay (Cuba): a tool for coastal ecosystem management.

    Science.gov (United States)

    Díaz-Asencio, M; Alvarado, J A Corcho; Alonso-Hernández, C; Quejido-Cabezas, A; Ruiz-Fernández, A C; Sanchez-Sanchez, M; Gómez-Mancebo, M B; Froidevaux, P; Sanchez-Cabeza, J A

    2011-11-30

    Since 1998 the highly polluted Havana Bay ecosystem has been the subject of a mitigation program. In order to determine whether pollution-reduction strategies were effective, we have evaluated the historical trends of pollution recorded in sediments of the Bay. A sediment core was dated radiometrically using natural and artificial fallout radionuclides. An irregularity in the (210)Pb record was caused by an episode of accelerated sedimentation. This episode was dated to occur in 1982, a year coincident with the heaviest rains reported in Havana over the XX century. Peaks of mass accumulation rates (MAR) were associated with hurricanes and intensive rains. In the past 60 years, these maxima are related to strong El Niño periods, which are known to increase rainfall in the north Caribbean region. We observed a steady increase of pollution (mainly Pb, Zn, Sn, and Hg) since the beginning of the century to the mid 90 s, with enrichment factors as high as 6. MAR and pollution decreased rapidly after the mid 90 s, although some trace metal levels remain high. This reduction was due to the integrated coastal zone management program introduced in the late 90 s, which dismissed catchment erosion and pollution. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. PAHs composition of surface marine sediments: a comparison to potential local sources in Todos Santos Bay, B.C., Mexico.

    Science.gov (United States)

    Macías-Zamora, J V; Mendoza-Vega, E; Villaescusa-Celaya, J A

    2002-01-01

    The analysis of the 16 polyaromatic hydrocarbons (PAHs) listed as priority pollutants by EPA, was carried out on surface sediments at 32 stations at Todos Santos Bay, Baja California, Mexico. The purpose was to investigate concentration levels, distribution patterns and relate them to three suspected local sources. The PAHs composition of car exhaust, grass and shrubs combustion, and asphalt and tire dust, were all compared to the relative abundance of PAHs signature found on marine sediments of the bay. We used GC-MS analysis in selected ion monitoring (SIM) mode. The total concentration found was low (from 7.6 to 813 ng/g of dry sediment. The average concentration was 96 ng/g). PAHs concentration was somewhat correlated (r = 0.612; P Todos Santos Canyon. The largest concentrations found were those of fluoranthene (120.6 ng/g), Indene(1,2,3-c,d)pyrene (115.6 ng/g) and pyrene (109.9 ng/g). Percentagewise, the main components were PAHs with three and four rings. Several indexes were used to investigate origins including simple PAH ratios and ternary plots. These indexes and plots suggest the main origin as a combination of urban air and wood and brush fires with little influence of oil.

  8. Application of neural network and MODIS 250 m imagery for estimating suspended sediments concentration in Hangzhou Bay, China

    Science.gov (United States)

    Wang, Fan; Zhou, Bin; Xu, Jianming; Song, Lishong; Wang, Xin

    2009-01-01

    Suspended sediments concentration (SSC) in surface water derived from bottom sediment resuspension or discharge of sediment-laden rivers is an important indication of coastal water quality and changes rapidly in high-energy coastal area. Since artificial neural networks (ANN) had been proven successful in modeling a variety of geophysical transfer functions, an ANN model to simulate the relationship between surface water SSC and satellite-received radiances was employed. In situ SSC measurements from the Hangzhou Bay and the Moderate-resolution Imaging Spectroradiometer (MODIS) 250 m daily products were adopted in this study. Significant correlations were observed between in situ measurements and band 1-2 reflectance values of MODIS images, respectively. Results indicated that application of ANN model with one hidden layer appeared to yield superior simulation performance ( r 2 = 0.98; n = 25) compared with regression analysis method. The RMSE for the ANN model was less than 10%, whereas the RMSE for the regression analysis was more than 25%. Results also showed that different tidal situations affect the model simulation results to some extent. The SSC of surface water in Hangzhou Bay is high and changes rapidly due to tidal flood and ebb during a tidal cycle. The combined utilization of Terra and Aqua MODIS data can capture the tidal cycle induced dynamic of surface water SSC. This study demonstrated that MODIS 250 m daily products and ANN model are useful for monitoring surface SSC dynamic within high-energy coastal water environments.

  9. Sources and distribution of aliphatic and polyaromatic hydrocarbons in coastal sediments from the Ushuaia Bay (Tierra del Fuego, Patagonia, Argentina).

    Science.gov (United States)

    Commendatore, Marta G; Nievas, Marina L; Amin, Oscar; Esteves, José L

    2012-03-01

    The environmental quality of Ushuaia Bay, located at the southernmost tip of South America, is affected by the anthropogenic pressure of Ushuaia city. In this study, levels and sources of hydrocarbons in coastal sediments were assessed. Aliphatic hydrocarbon fractions ranged between 5.5 and 1185.3 μg/g dry weight and PAHs from not detected to 360 ng/g. Aliphatic diagnostic indices, the nalkanes homologous series occurrence, Aliphatic Unresolved Complex Mixtures (AliUCMs), and pristane and phytane isoprenoids indicated a petrogenic input. Some sites showed biogenic features masked by the anthropogenic signature. Particularly in port areas biodegradation processes were evident. PAH ratios showed a mixture of petrogenic and pyrogenic sources. Aliphatic and aromatic UCMs were strongly correlated, reflecting chronic pollution. Three areas were distinguished inside the bay: (1) east, with low hydrocarbons impact; (2) central, where hydrocarbons accumulation was related to source proximity and sediment characteristics; (3) south-west, where sediment characteristics and current circulation favour hydrocarbons accumulation. Copyright © 2011 Elsevier Ltd. All rights reserved.

  10. Vertical profiles of dioxin-like and estrogenic activities associated with a sediment core from Tokyo Bay, Japan

    Energy Technology Data Exchange (ETDEWEB)

    Kannan, K.; Villeneuve, D.L.; Yamashita, N.; Imagawa, T.; Hashimoto, S.; Miyazaki, A.; Giesy, J.P. [Michigan State University, East Lansing, MI (USA). Dept. of Zoology

    2000-09-01

    In vitro bioassays were used to measure dioxin-like and estrogenic activities associated with florisil fractions of extracts from a sediment core collected from Tokyo Bay, Japan. Florisil fractions 2(F2) and 3(F3) elicited significant dioxin-like responses in vitro. Dioxin-like activity of F2 samples were correlated with the vertical profile of PAH concentrations (R{sup 2} = 0.85). Contribution of PAHs to Ah receptor-mediated activities in sediments was greater than those by PCDDs/DFs, PCBs, and PCNs. The dioxin-like activity of F3 samples suggests the presence of relatively polar, Ah receptor-active compounds in the Tokyo Bay sediment core. Significant estrogenic activities, which may be related to the presence of certain estrogenic PAHs, were observed for F2 samples. Estrogen equivalents (E2-EQs) calculated from the concentrations and relative potencies of known estrogenic compounds in F2 were greater than bioassay-derived E2-EQs. This suggests that complex interactions between estrogenic and antiestrogenic compounds (PAHs, PCDD/DFs, and PCNs) may have modulated the activity. F3 samples were toxic to MVLN cells; therefore, their estrogenic activities could not be estimated. 27 refs., 4 figs., 3 tabs.

  11. 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

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

    Science.gov (United States)

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

    2016-05-01

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

  13. CHARACTERIZING THE ORGANIC MATTER IN SURFACE SEDIMENTS FROM THE SAN JUAN BAY ESTUARY

    Science.gov (United States)

    The San Juan Bay Estuary (SJBE) is located on the north coast of Puerto Rico and includes the San Juan Bay, San José Lagoon, La Torrecilla Lagoon and Piñones Lagoon, as well as the Martín Peña and the Suárez Canals. The SJBE watershed has the highest...

  14. CHARACTERIZING THE ORGANIC MATTER IN SURFACE SEDIMENTS FROM THE SAN JUAN BAY ESTUARY.

    Science.gov (United States)

    The San Juan Bay Estuary (SJBE) is located on the north coast of Puerto Rico and includes the San Juan Bay, San José Lagoon, La Torrecilla Lagoon and Piñones Lagoon, as well as the Martín Peña and the Suárez Canals. The SJBE watershed has the highest...

  15. Effects of Sediment Characteristics on the Accumulation and Transfer Rate of Heavy Metals in Mangrove Trees (Case Study: Nayband Bay and Qeshm Island

    Directory of Open Access Journals (Sweden)

    H. Moradi

    2014-09-01

    Full Text Available In this paper, the accumulation of heavy metals of Nickel (Ni and Vanadium (V was measured in habitat sediments, mangrove roots and leaves (Avicennia marina. Besides, the transfer of Ni and V from the sediment to root and to the leaves in Nayband Bay and Qeshm Island were studied. The samples were gathered by Systematic-random Sampling using selective transects at 16 stations at the end of mangrove cover in both sides of land and sea in two habitats with three replicates of sediment, root and leave samples. The bed characteristics including sediment texture, pH, EC and organic matters were determined. The concentration of Ni and V was measured by atomic absorption spectroscopy (AAS, and then the metal transfer factor from sediment to root and root to leave was calculated. The correlation of the metal transfer factor and sediment characteristics was analyzed using the SPSS software (version 19. In the sample of sediments, roots and leaves respectively, the most concentrations of nickel and vanadium were measured. About transfer of Ni and V, transfer rate from sediment to root was much higher than from root to leave. In addition, the highest transfer factor from sediment to root and from root to leave was obtained for V in Qeshm habitat (0.502 and for Ni (0.749 in Nayband Bay. It seems that the difference between sediment textures in the two habitats and widespread oil and gas activities in Nayband Bay might be the notable reasons for the difference in transfer rates in two the habitats. Therefore, we conclude that the finer texture of Qeshm habitat increased transfer of V from sediment to root, and the coarser texture associated with increasing air pollution in Nayband Bay caused more Ni to accumulate in the leaves.

  16. Polybrominated diphenyl ethers in dissolved and suspended phases of seawater and in surface sediment from Jiaozhou Bay, North China.

    Science.gov (United States)

    Ju, Ting; Ge, Wei; Jiang, Tao; Chai, Chao

    2016-07-01

    The concentration and distribution of polybrominated diphenyl ethers (PBDEs) in the dissolved phase (DP) and suspended particulate matter (SPM) of seawater and in surface sediment obtained from Jiaozhou Bay (JZB) were determined. The potential sources of these compounds were evaluated. The total concentrations of 14 PBDEs (∑14PBDE) in DP and SPM were 0.09-1.35 and 1.17-5.45ng/L, respectively, indicating that the PBDE congeners are predominantly partitioned into the SPM fraction. The ∑14PBDE concentrations in sediment ranged from 2.18ng/g to 10.59ng/g with a mean value of 6.59ng/g. BDE-209 was dominant among 14 PBDE congeners, and BDE-47 was another abundant congener in the SPM and sediment samples. The PBDE concentration in SPM showed a significantly positive correlation with chlorophyll a level (r(2)=0.496, pparametric multidimensional scaling ordination showed that BDE-209 and BDE-47 are the important products discriminating PBDE contamination. This result is associated with industrial waste discharge from urban areas and with heavy ship traffic, indicating that DecaBDE and PentaBDE products are the potential sources of PBDEs. PBDE concentrations were lower in the sediment in JZB than in other coastal areas in South China, although the PBDE concentrations in DP were higher than those in some coastal areas worldwide. Moreover, the PBDE concentrations in DP and sediment increased in the last decade.

  17. Seismically induced soft-sediment deformation structures in the Palaeogene deposits of the Liaodong Bay Depression in the Bohai Bay basin and their spatial stratigraphic distribution

    Science.gov (United States)

    Liu, Lei; Zhong, Yijiang; Chen, Hongde; Xu, Changgui; Wu, Kui

    2016-08-01

    Soft-sediment deformation structures (SSDS) have been identified from well cores in the Palaeogene deposits of the Liaodong Bay Depression in the Bohai Bay basin, China. These deposits formed as interbedded sand and mud at a delta front or on the slope toe of the prodelta. According to criteria proposed by previous research, we established that these SSDS were induced by earthquakes and that they can be divided into two groups: ductile deformation structures (plastic intrusions, ball-and-pillow structures, flame structures, boudinage structures, irregular convolute stratifications, and synsedimentary faults and folds) and brittle deformation structures (sand dykes and autoclastic breccias). Based on their level of deformation, size, and complexity, the SSDS were divided into three Groups, from weak to strong, to reflect the intensity of palaeo-earthquakes. With consideration of the palaeo-sedimentary environment, we proposed a model to account for the production and preservation of these SSDS. According to the classification adopted in this study and the spatial stratigraphic distribution of the SSDS, the tectonic activities of the Tan-Lu faults in the Bohai Bay basin were investigated. The A and B oilfields (assumed names) are located in the tectonically active zones of the west and east branches of these faults, respectively. The extension tectonic activities in the A oilfield region exhibit a sharply decreasing trend from E2s3 to E2s1, and increase again in E3d2; whereas the strike-slip tectonic activities in the B oilfield region exhibit an increasing trend from E2s3 to E2s1, and finally, reach a maximum to E3d3. The results of this study show that the method of analysis of the spatial stratigraphic distribution of SSDS is suitable for determining the evolution of tectonic activity and thus, it can provide a new perspective for basin analysis.

  18. Dinoflagellate cyst production in Hudson Bay, the world's largest inland sea, based on monthly sediment trap data

    Science.gov (United States)

    Heikkilä, Maija; Pospelova, Vera; Forest, Alexandre; Stern, Gary

    2014-05-01

    Phytoplankters, microscopic primary producers of oceans are capable of responding rapidly to environmental fluctuations due to their high cell replication rates. Fast phytoplankton growth maybe balanced out by equally fast consumption by herbivorous grazers. In high-latitude marine systems, seasonal fluctuations in plankton biomass are essentially linked to light regime controlled by the waxing and waning sea-ice cover. In addition, nutrient limitation in surface waters, seasonal temperature fluctuations and changes in freshwater inputs may play important roles. In cold-water seas, many planktonic organisms cope with seasonal harshness by the production of benthic dormant stages. Dinoflagellates are a diverse group of single-celled plankton, constituting major marine primary producers, as well as herbivorous grazers of the microbial loop. Many dinoflagellate species produce highly resistant, organic-walled resting cysts that are archived in sediments and have been increasingly used to reconstruct past environmental conditions, e.g., sea-surface temperature and salinity, productivity, sea-ice cover and eutrophication. Marine sediment core sequences are characterized by slow accumulation rates and high mixing rates: the top centimeter of surface sediment from an arctic shelf may correspond to several years or decades of deposition. Consequently, sedimentary archives do not give direct information on long-term changes in seasonal bloom patterns or cues of annually recurring life-cycle events. We used two particle-intercepting sediment traps moored in eastern and western Hudson Bay, respectively, to study monthly fluctuations in dinoflagellate cyst production from October 2005 to September 2006. The traps were deployed close to the seafloor and recovered during the ArcticNet annual expeditions onboard the CCGS Amundsen in 2005 and the CCGS Pierre Radisson in 2006. We document the seasonal succession of dinoflagellate cyst taxa, together with cyst species composition

  19. Sediment chronology in San Francisco Bay, California, defined by 210Pb, 234Th, 137Cs, and 239,340Pu

    Science.gov (United States)

    Fuller, C.C.; van Geen, Alexander; Baskaran, M.; Anima, R.

    1999-01-01

    Sediment chronologies based on radioisotope depth profiles were developed at two sites in the San Francisco Bay estuary to provide a framework for interpreting historical trends in organic compound and metal contaminant inputs. At Richardson Bay near the estuary mouth, sediments are highly mixed by biological and/or physical processes. Excess  penetration ranged from 2 to more than 10 cm at eight coring sites, yielding surface sediment mixing coefficients ranging from 12 to 170 cm2/year. At the site chosen for contaminant analyses, excess  activity was essentially constant over the upper 25 cm of the core with an exponential decrease below to the supported activity between 70 and 90 cm. Both  and  penetrated to 57-cm depth and have broad subsurface maxima between 33 and 41 cm. The best fit of the excess  profile to a steady state sediment accumulation and mixing model yielded an accumulation rate of 0.825 g/cm2/year (0.89 cm/year at sediment surface), surface mixing coefficient of 71 cm2/year, and 33-cm mixed zone with a half-Gaussian depth dependence parameter of 9 cm. Simulations of  and  profiles using these parameters successfully predicted the maximum depth of penetration and the depth of maximum  and  activity. Profiles of successive 1-year hypothetical contaminant pulses were generated using this parameter set to determine the age distribution of sediments at any depth horizon. Because of mixing, sediment particles with a wide range of deposition dates occur at each depth. A sediment chronology was derived from this age distribution to assign the minimum age of deposition and a date of maximum deposition to a depth horizon. The minimum age of sediments in a given horizon is used to estimate the date of first appearance of a contaminant from its maximum depth of penetration. The date of maximum deposition is used to estimate the peak year of input for a contaminant from the depth interval with the highest concentration of that contaminant

  20. Distribution and generic composition of culturable marine actinomycetes from the sediments of Indian continental slope of Bay of Bengal

    Institute of Scientific and Technical Information of China (English)

    Surajit DAS; P.S.LYLA; S.AJMAL KHAN

    2008-01-01

    Actinomycetes population from continental slope sediment of the Bay of Bengal was studied.Samples were collected during two voyages of FORV Sagar Sampada in 2004 (May-June) and 2005 (July) respectively from 11 transects (each transect had ca.200m,500m,and 1000m depth stations).The physicochemical parameters of overlying water,and sediment samples were also recorded.The actinomycete population ranged from 5.17 to 51.94 CFU/g dry sediment weight and 9.38 to 45.22 CFU/g dry sediment weight during the two cruises respectively.No actinomycete colony was isolated from stations in 1000m depth.Two-way analysis of variance showed significant variation among stations (ANOVA two-way,P0.05),but no significance was found between the two cruises (ANOVA two-way,P0.05).Three actinomycetes genera were identified.Streptomyces was found to be the dominating one in both the cruises,followed by Micromonospora,and Actinomyces.The spore of Streptomyces isolates showed the abundance in spiral spore chain.Spore surface was smooth.Multiple regression analysis revealed that the influencing physico-chemical factors were sediment pH,sediment temperature,TOC,porosity,salinity,and pressure.The media used in the present study was prepared with seawater.Thus,they may represent an autochthonous marine flora and deny the theory of land runoff carriage into the sea for adaptation to the salinity of the seawater and sediments.

  1. RHEOLOGICAL PROPERTIES OF SEDIMENT SUSPENSIONS FROM ECKERNF(O)RDE AND KIELER F(O)RDE BAYS, WESTERN BALTIC SEA

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Local areas of fine-grained organic-rich sediments in Eckernforde and Kieler Forde Bays may experience disturbances which cause fluidization of the substrate and create a dense suspension (fluid mud) which exists temporarily as a component of the benthic boundary layer before becoming incorporated into the permanent bottom. Laboratory studies indicate this material behaves rheologically as a non-Newtonian substance, and both shear thinning (pseudoplastic) and shear thickening (dilatant) flow behavior can occur (often within the same sample) under low to intermediate shear stresses (2 - 40 Pa) and shear rates (0.46 - 122.49 s-1).Detailed granulometric analyses (1/4 phi intervals) of the fraction <63 μm show differences in the silt/clay ratio (clay <2 μm) between the two environments. Little change in the silt/clay ratio is seen in the Kieler Forde sediments (from 0.74 to 0.95); however, at Eckemforde, the ratio changed from0.73 to 2.19. Fine silt particles are lacking or were removed from the 4 to 16 μm fraction of the Eckernforde but not from the Kieler Forde sediments. Both shear thickening and shear thinning flow was observed in the Eckemforde sediments. Shear thickening flow behavior was not observed in the Kieler Forde sediments.Samples of organic-rich (10 to 20%) interface sediments from both areas were analyzed rheologically prior to, and after removal of organic matter by H2O2 treatment. Reduction in 'apparent'viscosity occurred through the entire range of shear rates and stresses, shear thickening behavior was reduced or became nonexistent, and yield stress decreased significantly compared to the natural samples. The differences in yield stress and flow behavior of dense suspensions result primarily from differences in grain size distributions but the role of organic matter on those properties is very significant and adds to the effects of the grain size distribution of the sediment.

  2. Influence of climate on deep-water clastic sedimentation: application of a modern model, Peru-Chile Trough, to an ancient system, Ouachita Trough

    Science.gov (United States)

    Edgar, N. Terence; Cecil, C. Blaine

    2003-01-01

    Traditionally, an abrupt and massive influx of siliciclastic sediments into an area of deposition has been attributed to tectonic uplift without consideration of the influence of climate or climatic change on rates of weathering, erosion, transportation, and deposition. With few exceptions, fluvial sediment transport is minimal in both extremely arid climates and in perhumid (everwet) climates. Maximum sediment transport occurs in climates characterized by strongly seasonal rainfall, where the effect of vegetation on erosion is minimal. The Peru–Chile trench and Andes Mountain system (P–CT/AMS) of the eastern Pacific Ocean clearly illustrates the effects of climate on rates of weathering, erosion, transport, and deep-sea sedimentation. Terrigenous sediment is virtually absent in the arid belt north of lat. 30° S in the P–CT, but in the belt of seasonal rainfall south of lat. 30° S terrigenous sediment is abundant. Spatial variations in the amount and seasonality of annual precipitation are now generally accepted as the cause for this difference. The spatial variation in sediment supply to the P–CT appears to be an excellent modern analogue for the temporal variation in sediment supply to certain ancient systems, such as the Ouachita Trough in the southern United States. By comparison, during the Ordovician through the early Mississippian, sediment was deposited at very slow rates as the Ouachita Trough moved northward through the southern hemisphere dry belt (lat. 10° S to lat. 30° S). The deposystem approached the tropical humid zone during the Mississippian, coincident with increased coarse clastic sedimentation. By the Middle Pennsylvanian (Atokan), the provenance area and the deposystem moved well into the tropical humid zone, and as much as 8,500 m of mineralogically mature (but texturally immature) quartz sand was introduced and deposited. This increase in clastic sediment deposition traditionally has been attributed solely to tectonic activity

  3. Geochemistry of organic carbon and nitrogen in surface sediments of coastal Bohai Bay inferred from their ratios and stable isotopic signatures.

    Science.gov (United States)

    Gao, Xuelu; Yang, Yuwei; Wang, Chuanyuan

    2012-06-01

    Total organic carbon (TOC), total nitrogen (TN) and their δ(13)C and δ(15)N values were determined for 42 surface sediments from coastal Bohai Bay in order to determine the concentration and identify the source of organic matter. The sampling sites covered both the marine region of coastal Bohai Bay and the major rivers it connects with. More abundant TOC and TN in sediments from rivers than from the marine region reflect the situation that most of the terrestrial organic matter is deposited before it meets the sea. The spatial variation in δ(13)C and δ(15)N signatures implies that the input of organic matter from anthropogenic activities has a more significant influence on its distribution than that from natural processes. Taking the area as a whole, surface sediments in the marine region of coastal Bohai Bay are dominated by marine derived organic carbon, which on average accounts for 62±11% of TOC.

  4. From Sediment to Top Predators: Broad Exposure of Polyhalogenated Carbazoles in San Francisco Bay (U.S.A.).

    Science.gov (United States)

    Wu, Yan; Tan, Hongli; Sutton, Rebecca; Chen, Da

    2017-02-21

    The present study provides the first comprehensive investigation of polyhalogenated carbazoles (PHCZs) contamination in an aquatic ecosystem. PHCZs have been found in soil and aquatic sediment from several different regions, but knowledge of their bioaccumulation and trophodynamics is extremely scarce. This work investigated a suite of 11 PHCZ congeners in San Francisco Bay (United States) sediment and organisms, including bivalves (n = 6 composites), sport fish (n = 12 composites), harbor seal blubber (n = 18), and bird eggs (n = 8 composites). The most detectable congeners included 3,6-dichlorocarbazole (36-CCZ), 3,6-dibromocarbazole (36-BCZ), 1,3,6-tribromocarbazole (136-BCZ), 1,3,6,8-tetrabromocarbazole (1368-BCZ), and 1,8-dibromo-3,6-dichlorocarbazole (18-B-36-CCZ). The median concentrations of ΣPHCZs were 9.3 ng/g dry weight in sediment and ranged from 33.7 to 164 ng/g lipid weight in various species. Biomagnification was observed from fish to harbor seal and was mainly driven by chlorinated carbazoles, particularly 36-CCZ. Congener compositions of PHCZs differed among species, suggesting that individual congeners may be subject to different bioaccumulation or metabolism in species occupying various trophic levels in the studied aquatic system. Toxic equivalent (TEQ) values of PHCZs were determined on the basis of their relative effect potencies (REP) compared to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The median TEQ was 1.2 pg TEQ/g dry weight in sediment and 4.8-19.5 pg TEQ/g lipid weight in biological tissues. Our study demonstrated the broad exposure of PHCZs in San Francisco Bay and their characteristics of bioaccumulation and biomagnification along with dioxin-like effects. These findings raise the need for additional research to better elucidate their sources, environmental behavior, and fate in global environments.

  5. Sediment and Crustal Structure along 85oE and Ninetyeast Ridges in the Bay of Bengal: Geodynamic Implications

    Science.gov (United States)

    Munukutla, R.; Gangumalla, S. R.; Sreejith, K. M.; Krishna, K. S.; Bull, J. M.

    2015-12-01

    The Bay of Bengal (BOB) region is characterized by the presence of two linear N-S trending aseismic ridges, the 85°E and Ninetyeast ridges which have progressively buried below thick sediments towards north. We present here the results of an integrated interpretation of geophysical data using multichannel seismic reflection, gravity and magnetic datasets over these two ridges to study the crustal structure and mode of their emplacement. The ridges divide the deep sedimentary BOB region into three major sub-basins. Considering the sediment deposition pattern within the sub-basins and over the ridges, it is found that both ridge structures have played a role in sediment dispersal pattern during the pre- and post Bengal Fan sedimentation. The Geoid-Topography Ratio (GTR) analysis indicates that both the ridges are compensated at shallow depths. Seismically constrained gravity and magnetic models and flexural gravity modeling over these ridges support their volcanic origin, and suggest the following: i) 85°E Ridge was emplaced in off-ridge environment (Te=10-15 km); ii) the higher Te values of ~ 25 km over the Afanasy Nikitin Seamount (ANS) reflect the secondary emplacement of the seamount peaks in off-ridge environment, iii) that the emplacement of the Ninetyeast Ridge north of 2°N occurred in an off-ridge environment as indicated by higher Te values (25-30 km). These results attain significance in terms of understanding of the interactions between plume- volcanism and lithosphere in the Bay of Bengal.

  6. Response of suspended sediment concentration to tidal dynamics at a site inside the mouth of an inlet: Jiaozhou Bay (China

    Directory of Open Access Journals (Sweden)

    S. L. Yang

    2004-01-01

    Full Text Available Observations of fair weather currents and suspended sediment concentrations (SSC were made using an acoustic Doppler current profiler and two YSI turbidity sensors over a neap to spring time cycle at a site near the inner mouth of a semi-enclosed mesotidal-macrotidal embayment (Jiaozhou Bay to examine the influence of tidal dynamics on concentration and transport of suspended sediment. During the investigation, SSC varied from about 3 to 16 mg L–1 at the surface and about 6 to 40 mg L–1 close to the bed, while the current velocity reached 79 cm s–1 at the surface and 61 cm s–1 near the bed. SSC was tidally cyclic. The near-bed instantaneous SSC was closely related to current velocity with almost no time lag, indicating that the variability of SSC was governed by current-induced settling/resuspension. At the surface, however, instantaneous SSC was poorly related to instantaneous current velocity because the peak SSC tended to occur around ebb slack water. This suggests that the surface SSC was controlled by horizontal advection from landward higher concentration areas. Both at the surface and near the bed, on the other hand, tidally-averaged SSC was well correlated to tidal range and current speed. Current velocity and SSC were flood-dominated for all the tides investigated, which resulted in significant landward residual suspended sediment transport at the study site. The observed flood dominance was mainly attributed to the location of the study site on the landward side of the bay’s inlet where flow separation is favoured during flood tide. It was concluded that tides are the dominant hydrodynamic component controlling the variability of SSC during fair weather at the study area. Keywords: sediment, concentration, suspension, advection, currents, shoalling effect, Jiaozhou Bay, China

  7. Amphipod and Sea Urchin tests to assess the toxicity of Mediterranean sediments: the case of Portmán Bay

    Directory of Open Access Journals (Sweden)

    A. Cesar

    2004-04-01

    Full Text Available The sediment formed by the tailings of an abandoned mine, which discharged into Portmán Bay, Murcia, SE-Spain, was tested to establish a possible gradient of heavy metals. The results were compared with tolerance limits of what was calculated from control sites. Whole sediment toxicity tests were performed on two amphipod species, Gammarus aequicauda and Microdeutopus gryllotalpa, while sediment-water interface and porewater toxicity tests were performed on three sea urchins species, Arbacia lixula, Paracentrotus lividus and Sphaerechinus granularis. The sensitivity of these marine organisms was evaluated by exposure tests using the reference substances: ammonium chloride (NH4Cl, cadmium chloride (CdCl2, potassium dichromate (K2Cr2O7, sodium dodecyl sulfate (C12H25NaO4S and zinc sulfate (ZnSO4. The concentration of heavy metals decreased along the pollution gradient. Amphipod 10 day acute toxicity tests clearly demonstrated the gradient of toxicity. The sediment-water interface tests conducted with sea urchins also pointed to a pollution gradient and were more sensitive than the tests involving amphipods.

  8. Monitoring of dredged-dumped sediment dispersal off the Bay of the Seine (northern France) using environmental magnetism

    Science.gov (United States)

    Nizou, Jean; Demory, François; Dubrulle-Brunaud, Carole

    2016-07-01

    In this study, we developed a novel approach for fingerprinting dredged-dumped sediments at sea using magnetic susceptibility. Several magnetic measurements were performed on discrete sedimentary samples from the dredged areas in the Seine River and from the Bay of Seine seafloor before and after dumping. The dredged sediments showed higher susceptibility values than the undisturbed seafloor, which allowed the mapping of the dispersion of dredged-dumped sediments. In the vicinity of the coast and the estuary, high-susceptibility terrestrial input from rivers could also be mapped by this technique, therefore monitoring of the dumping by the susceptibility proxy is limited to the offshore areas. This susceptibility signal is controlled by the ferromagnetic fraction of the sediment. Furthermore, a constant magnetite-dominated magneto-mineralogy is observed in the study area. In addition to the susceptibility, a magnetic grain size parameter of the low-coercive fraction was also found to be sensitive to dumping. Both tracers showed an in progress resilience of the sedimentary environment during a 6-month survey.

  9. Prevalence of Vibrio parahaemolyticus, and Vibrio vulnificus in blue crabs (Callinectes sapidus), seawater and sediments of the Maryland Coastal Bays.

    Science.gov (United States)

    Rodgers, C; Parveen, S; Chigbu, P; Jacobs, J; Rhodes, M; Harter-Dennis, J

    2014-10-01

    To determine the prevalence of total and pathogenic Vibrio parahaemolyticus (Vp) and V. vulnificus (Vv) in blue crabs, water and sediment from the Maryland Coastal Bays (MCBs), USA. Crab, haemolymph, sediment and seawater samples were collected monthly from four sites in MCBs from February 2012 through October 2012 with environmental parameters recorded. The most-probable-number (MPN) methodology was used to enumerate Vp and Vv with presumptive colonies and the presence of virulence markers confirmed using polymerase chain reaction (PCR). Results indicate that blue crabs contained both Vp and Vv at densities (7·28 and 5·43 log MPN g(-1) , respectively) higher than those reported for bivalves. In addition, markers for clinically relevant strains of both species were detected in over 30% of samples. Haemolymph, sediment and seawater samples were also routinely positive for both species and clinically relevant strains, but generally at lower densities than found in crabs (4·27, 3·28, and 2·39 log MPN g(-1) per ml(-1) Vp, and 4·28, 2·49 and 2·38 log MPN g(-1) per ml(-1) Vv). Blue crabs concentrate Vp and Vv at levels greater than found in water or sediment. While changes in abundance associated with temperature are apparent, there is little evidence to support differences among sampling locations. These results highlight the potential for blue crab related vibriosis and the importance of proper handling, cooking and care of this popular seafood before consumption. © 2014 The Society for Applied Microbiology.

  10. Preserving Chile

    OpenAIRE

    Brennand, Charlotte P.

    2010-01-01

    The best way to preserve chile depends on how you plan to use it and your available storage space. Frozen or canned chile is best for chile rellenos and salsas. Stews can use frozen, canned or dried chile. Dried chile has minimal storage requirements and is light-weight for taking on camping trips. Pickled chiles can be used on a relish plate or as an ingredient in other dishes.

  11. Trajectory of early tidal marsh restoration: elevation, sedimentation and colonization of breached salt ponds in the northern San Francisco Bay

    Science.gov (United States)

    Brand, L. Arriana; Smith, Lacy M.; Takekawa, John Y.; Athearn, Nicole D.; Taylor, Karen; Shellenbarger, Gregory; Schoellhamer, David H.; Spenst, Renee

    2012-01-01

    Tidal marsh restoration projects that cover large areas are critical for maintaining target species, yet few large sites have been studied and their restoration trajectories remain uncertain. A tidal marsh restoration project in the northern San Francisco Bay consisting of three breached salt ponds (≥300 ha each; 1175 ha total) is one of the largest on the west coast of North America. These diked sites were subsided and required extensive sedimentation for vegetation colonization, yet it was unclear whether they would accrete sediment and vegetate within a reasonable timeframe. We conducted bathymetric surveys to map substrate elevations using digital elevation models and surveyed colonizing Pacific cordgrass (Spartina foliosa). The average elevation of Pond 3 was 0.96 ± 0.19 m (mean ± SD; meters NAVD88) in 2005. In 2008–2009, average pond elevations were 1.05 ± 0.25 m in Pond 3, 0.81 ± 0.26 m in Pond 4, and 0.84 ± 0.24 m in Pond 5 (means ± SD; meters NAVD88). The largest site (Pond 3; 508 ha) accreted 9.5 ± 0.2 cm (mean ± SD) over 4 years, but accretion varied spatially and ranged from sediment loss in borrow ditches and adjacent to an unplanned, early breach to sediment gains up to 33 cm in more sheltered regions. The mean elevation of colonizing S. foliosa varied by pond (F = 71.20, df = 84, P S. foliosa. Our results suggest that sedimentation to elevations that enable vegetation colonization is feasible in large sites with sufficient sediment loads although may occur more slowly compared with smaller sites.

  12. Contrasting sedimentation patterns in two semi-enclosed mesotidal bays along the west and south coasts of Korea controlled by their orientation to the regional monsoon climate

    Science.gov (United States)

    Hong, Seok Hwi; Chun, Seung Soo; Chang, Tae Soo; Jang, Dae Geon

    2017-08-01

    Sedimentation patterns of tidal flats along the Korean west coast have long been known to be largely controlled by the monsoon climate. On the other hand, much less is known about the effect of the monsoon on sedimentation in coastal embayments with mouths of different geographic orientations. Good examples are Hampyeong and Yeoja bays along the west and south coasts, respectively. Both have narrow entrances, but their mouths open toward the northwest and the south, respectively. With mean tidal ranges of 3.46 and 3.2 m, respectively, the two bays experience similar tidal regimes and are hence excellent candidates to compare the effect of different exposure to the same regional monsoon climate on their respective sediment distribution patterns. The winter monsoon, in particular, is characterized by strong northwesterly winds that directly impact the west coast, but blow offshore along the south coast. For the purpose of this study, surficial sediment samples were collected from intertidal and subtidal flats of the two bays, both in summer and winter. Grain-size analyses were carried out by sieving (sand fraction) and Sedigraph (mud fraction). In the case of Yeoja Bay, the sediments consist mostly of mud (mean grain sizes of 5.4 to 8.8 phi). Seasonal changes are very subtle, the sediments being slightly coarser in summer when silt-dominated sediments are supplied by two streams to the northern parts of the bay in response to heavy rainfall. With the exception of the deeper tidal channels, Yeoja Bay is characterized by a thick mud blanket the year round, which is modulated by processes associated with the summer monsoon that predominantly blows from the east. Textural parameters suggest severely restricted sediment mixing on the subtidal and intertidal flats, the overall low energy situation preventing sands from reaching the tidal flats. The sediments of Hampyeong Bay, by contrast, are characterized by a distinct shoreward fining trend. Mean grain sizes average

  13. Contrasting sedimentation patterns in two semi-enclosed mesotidal bays along the west and south coasts of Korea controlled by their orientation to the regional monsoon climate

    Science.gov (United States)

    Hong, Seok Hwi; Chun, Seung Soo; Chang, Tae Soo; Jang, Dae Geon

    2016-11-01

    Sedimentation patterns of tidal flats along the Korean west coast have long been known to be largely controlled by the monsoon climate. On the other hand, much less is known about the effect of the monsoon on sedimentation in coastal embayments with mouths of different geographic orientations. Good examples are Hampyeong and Yeoja bays along the west and south coasts, respectively. Both have narrow entrances, but their mouths open toward the northwest and the south, respectively. With mean tidal ranges of 3.46 and 3.2 m, respectively, the two bays experience similar tidal regimes and are hence excellent candidates to compare the effect of different exposure to the same regional monsoon climate on their respective sediment distribution patterns. The winter monsoon, in particular, is characterized by strong northwesterly winds that directly impact the west coast, but blow offshore along the south coast. For the purpose of this study, surficial sediment samples were collected from intertidal and subtidal flats of the two bays, both in summer and winter. Grain-size analyses were carried out by sieving (sand fraction) and Sedigraph (mud fraction). In the case of Yeoja Bay, the sediments consist mostly of mud (mean grain sizes of 5.4 to 8.8 phi). Seasonal changes are very subtle, the sediments being slightly coarser in summer when silt-dominated sediments are supplied by two streams to the northern parts of the bay in response to heavy rainfall. With the exception of the deeper tidal channels, Yeoja Bay is characterized by a thick mud blanket the year round, which is modulated by processes associated with the summer monsoon that predominantly blows from the east. Textural parameters suggest severely restricted sediment mixing on the subtidal and intertidal flats, the overall low energy situation preventing sands from reaching the tidal flats. The sediments of Hampyeong Bay, by contrast, are characterized by a distinct shoreward fining trend. Mean grain sizes average

  14. Coastal circulation and sediment dynamics in Maunalua Bay, Oahu, Hawaii, measurements of waves, currents, temperature, salinity, and turbidity; November 2008-February 2009

    Science.gov (United States)

    Storlazzi, Curt D.; Presto, M. Katherine; Logan, Joshua B.; Field, Michael E.

    2010-01-01

    High-resolution measurements of waves, currents, water levels, temperature, salinity and turbidity were made in Maunalua Bay, southern Oahu, Hawaii, during the 2008-2009 winter to better understand coastal circulation, water-column properties, and sediment dynamics during a range of conditions (trade winds, kona storms, relaxation of trade winds, and south swells). A series of bottom-mounted instrument packages were deployed in water depths of 20 m or less to collect long-term, high-resolution measurements of waves, currents, water levels, temperature, salinity, and turbidity. These data were supplemented with a series of profiles through the water column to characterize the vertical and spatial variability in water-column properties within the bay. These measurements support the ongoing process studies being done as part of the U.S. Geological Survey (USGS) Coastal and Marine Geology Program's Pacific Coral Reef Project; the ultimate goal of these studies is to better understand the transport mechanisms of sediment, larvae, pollutants, and other particles in coral reef settings. Project Objectives The objective of this study was to understand the temporal variations in currents, waves, tides, temperature, salinity and turbidity within a coral-lined embayment that receives periodic discharges of freshwater and sediment from multiple terrestrial sources in the Maunalua Bay. Instrument packages were deployed for a three-month period during the 2008-2009 winter and a series of vertical profiles were collected in November 2008, and again in February 2009, to characterize water-column properties within the bay. Measurements of flow and water-column properties in Maunalua Bay provided insight into the potential fate of terrestrial sediment, nutrient, or contaminant delivered to the marine environment and coral larval transport within the embayment. Such data are useful for providing baseline information for future watershed decisions and for establishing guidelines for

  15. Coastal circulation and sediment dynamics in Maunalua Bay, Oahu, Hawaii, measurements of waves, currents, temperature, salinity, and turbidity; November 2008-February 2009

    Science.gov (United States)

    Storlazzi, Curt D.; Presto, M. Katherine; Logan, Joshua B.; Field, Michael E.

    2010-01-01

    High-resolution measurements of waves, currents, water levels, temperature, salinity and turbidity were made in Maunalua Bay, southern Oahu, Hawaii, during the 2008-2009 winter to better understand coastal circulation, water-column properties, and sediment dynamics during a range of conditions (trade winds, kona storms, relaxation of trade winds, and south swells). A series of bottom-mounted instrument packages were deployed in water depths of 20 m or less to collect long-term, high-resolution measurements of waves, currents, water levels, temperature, salinity, and turbidity. These data were supplemented with a series of profiles through the water column to characterize the vertical and spatial variability in water-column properties within the bay. These measurements support the ongoing process studies being done as part of the U.S. Geological Survey (USGS) Coastal and Marine Geology Program's Pacific Coral Reef Project; the ultimate goal of these studies is to better understand the transport mechanisms of sediment, larvae, pollutants, and other particles in coral reef settings. Project Objectives The objective of this study was to understand the temporal variations in currents, waves, tides, temperature, salinity and turbidity within a coral-lined embayment that receives periodic discharges of freshwater and sediment from multiple terrestrial sources in the Maunalua Bay. Instrument packages were deployed for a three-month period during the 2008-2009 winter and a series of vertical profiles were collected in November 2008, and again in February 2009, to characterize water-column properties within the bay. Measurements of flow and water-column properties in Maunalua Bay provided insight into the potential fate of terrestrial sediment, nutrient, or contaminant delivered to the marine environment and coral larval transport within the embayment. Such data are useful for providing baseline information for future watershed decisions and for establishing guidelines for

  16. Continuous water-quality and suspended-sediment transport monitoring in the San Francisco Bay, California, water years 2011-13

    Science.gov (United States)

    Buchanan, Paul A.; Downing-Kunz, Maureen A.; Schoellhamer, David H.; Shellenbarger, Gregory; Weidich, Kurt W.

    2014-01-01

    The U.S. Geological Survey (USGS) monitors water quality and suspended-sediment transport in the San Francisco Bay. The San Francisco Bay area is home to millions of people, and the bay teems with both resident and migratory wildlife, plants, and fish. Fresh water mixes with salt water in the bay, which is subject both to riverine and marine (tides, waves, influx of salt water) influences. To understand this environment, the USGS, along with its partners, has been monitoring the bay’s waters continuously since 1988. Several water-quality variables are of particular importance to State and Federal resource managers and are monitored at key locations throughout the bay. Salinity, which indicates the relative mixing of fresh and ocean waters in the bay, is derived from specific conductance measurements. Water temperature, along with salinity, affects the density of water, which causes gravity driven circulation patterns and stratification in the water column. Turbidity is measured using light-scattering from suspended solids in water, and is used as a surrogate for suspended-sediment concentration (SSC). Suspended sediment often carries adsorbed contaminants; attenuates sunlight in the water column; deposits on tidal marsh and intertidal mudflats, which can help sustain these habitats as sea level rises; and deposits in ports and shipping channels, which can necessitate dredging. Dissolved oxygen, which is essential to a healthy ecosystem, is a fundamental indicator of water quality, and its concentration is affected by water temperature, salinity, ecosystem metabolism, tidal currents, and wind. Tidal currents in the bay reverse four times a day, and wind direction and intensity typically change on a daily cycle: consequently, salinity, water temperature, suspendedsediment concentration, and dissolvedoxygen concentration vary spatially and temporally throughout the bay, and continuous measurements are needed to observe these changes. The purpose of this fact sheet

  17. Contenido de metales en Cancer polyodon (Crustacea: Decapoda en un sistema de bahías del norte de Chile (27°S Metal contents in Cancer polyodon (Crustacea: Decapoda in a bay system of northern Chile (27°S

    Directory of Open Access Journals (Sweden)

    Alexis Castillo

    2011-11-01

    Full Text Available El contenido de Zn, Cu, Cd, Pb, Fe, Al y Ni fue analizado en tejido muscular de Cancer polyodon en las bahías de Caldera, Calderilla, Inglesa y Salada (Atacama, Chile. Los resultados fueron comparados con estudios similares desarrollados por otros autores y la normativa de carácter nacional e internacional relacionada con el contenido de metales pesados en crustáceos para consumo humano. El orden de abundancia de los metales analizados en C. polyodon fue CdThe contents of Zn, Cu, Cd, Pb, Fe, Al and Ni in the muscle tissue of Cancer polyodon from Caldera, Calderilla, Inglesa, and Salada bays (Atacama, Chile were quantified. The results were compared with similar studies by other authors and with the national and international regulatory standards for heavy metal contents in crustaceans for human consumption. In increasing order, the metal contents in C. polyodon were: Cd< Ni< Cu< Pb< ZnBay: Cu and Ni were highest in Caldera Bay; and Zn was highest in Inglesa Bay. All the metals except Cu differed significantly (P < 0.05 among the analyzed bays. Of the seven metals analyzed, Pb, Fe, and Al concentrations in C. polyodon were higher than those reported for other coastal systems. Concentrations of Cu (except Calderilla, Cd (except Caldera and Inglesa, and Pb exceeded the threshold values indicated by the national and international standards, suggesting that the presence of these metals in C. polyodon represents a potential risk for human health.

  18. Biogeochemistry of sulfur and iron in Thioploca-colonized surface sediments in the upwelling area off central Chile

    DEFF Research Database (Denmark)

    Zopfi, Jakob; Michael E., Böttcher; Jørgensen, Bo Barker

    2008-01-01

    The biogeochemistry of sedimentary sulfur was investigated on the continental shelf off central Chile at water depths between 24 and 88 m under partial influence of an oxygen minimum zone. Dissolved and solid iron and sulfur species, including the sulfur intermediates sulfite, thiosulfate...

  19. Distributions of clay minerals in surface sediments of the middle Bay of Bengal: Source and transport pattern

    Science.gov (United States)

    Li, Jingrui; Liu, Shengfa; Shi, Xuefa; Feng, Xiuli; Fang, Xisheng; Cao, Peng; Sun, Xingquan; Wenxing, Ye; Khokiattiwong, Somkiat; Kornkanitnan, Narumol

    2017-08-01

    The clay mineral contents in 110 surface sediment samples collected from the middle of the Bay of Bengal were analyzed by X-ray diffraction (XRD) to investigate the provenance and transport patterns. The illite content was highest, followed by chlorite, kaolinite and then smectite, with average weight percent distributions of 52%, 22%, 14% and 12%, respectively. Illite and chlorite had similar distribution pattern, with higher contents in the northern and central areas and lower contents in the southern area, whereas smectite showed the opposite distribution pattern. Kaolinite show no obvious higher or lower areas and the southern ;belt; was one of the highest content areas. Based on the spatial distribution characteristics and cluster analysis results, the study area can be classified into two provinces. Province I covers the southwestern area and contains high concentrations of illite and smectite sediments. Province II covers most sites and is also characterized by high concentrations of illite, but the weight percent of smectite is only half of that of province I. According to a quantitative estimate using end-member clay minerals contents, the relative contributions from the Himalayan source and the Indian source are 63% and 37% on average, respectively. Integrative analysis indicates that the hydrodynamic environment in the study area, especially the turbidity and surface monsoonal circulation, plays an important role in the spatial distribution and dispersal of the clay fraction in the sediments. The sediments in province I are mainly from the Indian source transported by the East Indian Coastal Current (EICC) and the surface monsoon circulation with minor contributions from the Himalayan source while the sediments in province II are mainly from the Himalayan source transported by turbidity and surface monsoonal circulation with little contribution from Indian river materials.

  20. Endospore abundance and D:L-amino acid modeling of bacterial turnover in holocene marine sediment (Aarhus Bay)

    Science.gov (United States)

    Langerhuus, Alice T.; Røy, Hans; Lever, Mark A.; Morono, Yuki; Inagaki, Fumio; Jørgensen, Bo B.; Lomstein, Bente Aa.

    2012-12-01

    In order to study bacterial activity, and turnover times of bacterial necromass and biomass in marine sediment, two stations from the Aarhus Bay, Denmark were analyzed. Sediment cores were up to 11 m deep and covered a timescale from the present to ˜11,000 years ago. Sediment was analyzed for total hydrolysable amino acids (THAA), total hydrolysable amino sugars, the bacterial endospore marker dipicolinic acid (DPA), and amino acid enantiomers (L- and D-form) of aspartic acid. Turnover times of bacterial necromass and vegetative cells, as well as carbon oxidation rates were estimated by use of the D:L-amino acid racemization model. Diagenetic indicators were applied to evaluate the diagenetic state of the sedimentary organic matter. The contribution of amino acids to total organic carbon, and the ratio between the amino acids aspartic acid and glutamic acid, and their respective non protein degradation products, β-alanine and γ-amino butyric acid, all indicated increasing degradation state of the organic matter with sediment depth and age. Quantification of DPA showed that endospores were abundant, and increased with depth relative to vegetative cells. Most of the amino acids (97%) could be ascribed to microbial necromass, i.e. the remains of dead bacterial cells. Model estimates showed that the turnover times of microbial necromass were in the range of 0.5-1 × 105 years, while turnover times of vegetative cells were in the range of tens to hundreds of years. The turnover time of the TOC pool increased with depth in the sediment, indicating that the TOC pool became progressively more refractory and unavailable to microorganisms with depth and age of the organic matter.

  1. Runoff nutrient and suspended sediment fluxes, cycling, and management in southern Kaneohe Bay, Hawaii

    Science.gov (United States)

    Ringuet, S.; Young, C. W.; Hoover, D. J.; de Carlo, E. H.; MacKenzie, F. T.

    2003-12-01

    Urban runoff and its impact on water quality in Hawaii, especially after heavy rainfall, is highly dynamic. In the past, water quality was determined through "grab samples" that were merely snapshots in time of an ever-changing environment. In contrast, continuous measurements of water quality can capture data that reflect the effects of significant storm runoff events unobtainable using even frequent manual sampling. Continuous multiparameter monitoring facilitates investigation of the both the magnitude and persistence of impacts of storm runoff on coastal waters, which can eventually be related to the health of coral reef ecosystems. Taking advantage of recent technological developments in oceanographic instrumentation, our study assembled an instrument package dubbed Coral Reef Instrumented Monitoring Platform (CRIMP). CRIMP was designed to include probes that measure physical and biological parameters (temperature, salinity, pH, dissolved oxygen, turbidity, and chlorophyll-a), nutrient analyzers (nitrate and phosphate), and a particle analyzer based on laser in-situ scattering and transmissometry. Various components of the CRIMP were previously used in conjunction with grab samples with the objective of elucidating the water quality of southern Kaneohe Bay and its relationship to physical, biological, and chemical processes operating in the bay, and to coral reef ecosystems. All instruments are now being combined on the CRIMP, and will allow us to study in near real time changes in fluvial inputs to the bay during storm runoff conditions and their impact on bay water quality and the coral reef ecosystem. In this presentation we discuss effects of freshwater delivery on adjacent coastal waters during high rainfall episodes (May 2002 and Feb 2003) that result in large runoff events and increased nutrient loading to coastal waters. Dissolved inorganic nitrogen to phosphorus ratios (DIN:DIP) in the Bay normally range from 2 to 4, suggesting a nitrogen

  2. Geochemistry of trace metals in shelf sediments affected by seasonal and permanent low oxygen conditions off central Chile, SE Pacific (˜36°S)

    Science.gov (United States)

    Muñoz, Praxedes; Dezileau, Laurent; Cardenas, Lissette; Sellanes, Javier; Lange, Carina B.; Inostroza, Jorge; Muratli, Jesse; Salamanca, Marco A.

    2012-02-01

    Trace metals (Cd, U, Co, Ni, Cu, Ba, Fe, Mn), total organic carbon (TOC) and C and N stable isotope signatures (δ 13C and δ 15N) were determined in short sediments cores from the inner and outer shelf off Concepción, Chile (˜36°S). The objectives were to establish the effect of environmental conditions on trace metal distributions at two shelf sites, one affected by seasonal oxygenation and the other by permanent low oxygen conditions due to the presence of the oxygen minimum zone (OMZ). We evaluate trace metals as proxies of past changes in primary productivity and the bottom water oxygen regime. Concentrations of pore water sulfides and NH4+ were also measured as indicators of the main diagenetic pathways at each site. Our results for the inner shelf (seasonal suboxia) suggest that the oxidative state of the sediments responds to seasonal pulses of organic matter and that seasonal oxygenation develops during high and low primary productivity in the water column. Here, positive fluxes (to the water column) estimated from pore water concentrations of several elements were observed (Ba, Co, Ni, Fe and Mn). The less reduced environment at this site produces authigenic enrichment of Cu associated with the formation of oxides in the oxic surface sediment layer, and the reduction of U within deeper sediment sections occur consistently with negative estimated pore water fluxes. In the outer shelf sediments (permanent suboxia, OMZ site), negative fluxes (to the sediment) were estimated for all elements, but these sediments showed authigenic enrichments only for Cd, Cu and U. The short oxygenation period during the winter season did not affect the accumulation of these metals on the shelf. The distribution of Cu, Cd and U have been preserved within the sediments and the authigenic accumulation rates estimated showed a decrease from the deep sections of the core to the surface sediments. This could be explained by a gradual decrease in the strength of the OMZ in the

  3. Distribution and source identification of trace metals in the sediment of Yellow River Estuary and the adjacent Laizhou Bay

    Science.gov (United States)

    Wang, Yan; Ling, Min; Liu, Ru-hai; Yu, Ping; Tang, Ai-kun; Luo, Xian-xiang; Ma, Qimin

    2017-02-01

    Rapid economic development in the Yellow River basin has inevitably resulted in increase of pollution in the estuary, and concern for both the environment and protection against pollutants is increasing. Contents of trace metals (Cu, Pb Zn, Cr, Cd, As, Hg), Fe, Al, total organic carbon (TOC), and their granulometry were determined in surface sediment samples from the Yellow River estuary and its adjacent areas. Metal contents were significantly correlated each other. Clay, TOC and heavy metal contents showed similar distribution characteristics, with concentrations increased from the land to the sea. The distribution of grain size plays an important role in influencing the distribution of trace metals. Heavy metal concentrations showed a significant relationship with Fe and Al content, while most heavy metals were not enriched. These results were also confirmed by the analysis of enrichment factors and principal component analysis of the metals. The metal content of the Yellow River Estuary sediments was similar to the content observed 20 years ago, but the concentrations of most metals in Laizhou Bay decreased. The decrease in the carrying sediment of the Yellow River might be responsible for this pattern.

  4. Heavy metal pollution status in surface sediments of Swan Lake lagoon and Rongcheng Bay in the northern Yellow Sea.

    Science.gov (United States)

    Huang, Lili; Pu, Xinming; Pan, Jin-Fen; Wang, Bo

    2013-11-01

    The national 'Shandong Peninsula Blue Economic Zone Development Plan' compels the further understanding of the distribution and potential risk of metals pollution in the east coast of China, where the rapid economic and urban development have been taken off and metal pollution has become a noticeable problem. Surface sediments collected from the largest swan habitat in Asia, the Swan Lake lagoon and the surrounding coastal area in Rongcheng Bay in northern Yellow Sea, were analyzed for the total metal concentrations and chemical phase partitioning of five heavy metals (Cu, Zn, Pb, Cd, and Cr). Metal contents in the studied region have increased significantly in the past decade. The speciation analyzed by the sequential extraction showed that Zn and Cr were present dominantly in the residual fraction and thus of low bioavailability, while Cd, Pb and Cu were found mostly in the non-residual fraction thus of high potential availability, indicating significant anthropogenic sources. Among the five metals, Cd is the most outstanding pollutant and presents high risk, and half of the surface sediments in the studied region had a 21% probability of toxicity based on the mean Effect Range-Median Quotient. At some stations with comparable total metal contents, remarkably different non-residual fraction portions were determined, pointing out that site-specific risk assessment integrating speciation is crucial for better management practices of coastal sediments.

  5. Comparing sediment quality in Spanish littoral areas affected by acute (Prestige, 2002) and chronic (Bay of Algeciras) oil spills

    Energy Technology Data Exchange (ETDEWEB)

    Morales-Caselles, C. [Instituto de Ciencias Marinas de Andalucia (ICMAN-CSIC), Avda. Republica Saharaui s/n, Puerto Real 11510, Cadiz (Spain); Unidad Asociada de Calidad Ambiental y Patologia (CSIC and UCA), Avda. Republica Saharaui s/n, Puerto Real 11510, Cadiz (Spain); Kalman, J. [Instituto de Ciencias Marinas de Andalucia (ICMAN-CSIC), Avda. Republica Saharaui s/n, Puerto Real 11510, Cadiz (Spain); Unidad Asociada de Calidad Ambiental y Patologia (CSIC and UCA), Avda. Republica Saharaui s/n, Puerto Real 11510, Cadiz (Spain); Riba, I. [Instituto de Ciencias Marinas de Andalucia (ICMAN-CSIC), Avda. Republica Saharaui s/n, Puerto Real 11510, Cadiz (Spain); Unidad Asociada de Calidad Ambiental y Patologia (CSIC and UCA), Avda. Republica Saharaui s/n, Puerto Real 11510, Cadiz (Spain); DelValls, T.A. [UNESCO UNITWIN/UNICOP, Facultad de Ciencias del Mar y Ambientales, Universidad de Cadiz, Poligono Rio San Pedro s/n, Puerto Real 11510, Cadiz (Spain) and Unidad Asociada de Calidad Ambiental y Patologia - CSIC and UCA, Avda. Republica Saharaui s/n, Puerto Real 11510, Cadiz (Spain)]. E-mail: angel.valls@uca.es

    2007-03-15

    The quality of sediments collected from two areas of the Spanish coast affected by different sources of contaminants has been compared in this study. The areas studied are the coast of Galicia affected by the oil spill from the tanker Prestige (November 2002) and the Gulf of Cadiz which suffers continuous inputs of contaminants from industries located in the area and from oil spills. Contamination by several chemicals (metals, PCBs and PAHs) that bind to sediments was analyzed, and two toxicity tests (Microtox[reg]) and amphipod 10-day bioassay) were conducted. PAHs were identified as the compounds responsible for the toxic effects. Results show differences between an acute impact related to the sinking of the tanker Prestige and the chronic impact associated with continuous oil spills associated with the maritime and industrial activities in the Bay of Algeciras, this being the most polluted part of the two coastal areas studied in this work. - Littoral sediments affected by low or moderated but continuous oil spills are more polluted than those affected by accidental oil spills such as the Prestige.

  6. Consolidation and strength properties of calcareous sediments from Kaneohe and Kailua Bays, Hawaii

    Digital Repository Service at National Institute of Oceanography (India)

    Brandes, H.G.; Khadge, N; Nakayama, D.D

    -carbonate sediments do not seem to have a large effect on consolidation and triaxial behavior. Due to contrasting mineralogies between the land-derived volcanic soils and the calcareous sediment of marine origin, carbonate content is a useful property that serves...

  7. Modeling Benthic Sediment Processes to Predict Water Quality and Ecology in Narragansett Bay

    Science.gov (United States)

    The benthic sediment acts as a huge reservoir of particulate and dissolved material (within interstitial water) which can contribute to loading of contaminants and nutrients to the water column. A benthic sediment model is presented in this report to predict spatial and temporal ...

  8. Marine meiofauna, carbon and nitrogen mineralization in sandy and soft sediments of Disko Bay, West Greenland

    DEFF Research Database (Denmark)

    Rysgaard, S.; Christensen, P.B.; Sørensen, Martin Vinther

    2000-01-01

    layers of the sediment. Algal photosynthetic activity and nitrogen uptake reduced nitrogen effluxes and denitrification rates. Sulfate reduction was the most important pathway for carbon mineralization in the sediments of the shallow-water station. In contrast, high bottom-water NO3- concentrations...... and a relatively deep O-2 penetration into the sediment at the deep-water stations ensured high denitrification activity, particularly as a result of an efficient coupling between nitrification and denitrification. Denitrification accounted for up to 33 % of total carbon mineralization in the deep-water sediment......, corresponding to the 3 times higher number of meiofauna found in the upper 2 cm of this sediment. Thus, meiofauna increased the transport of solutes as compared to molecular diffusion by a factor of 1.5 to 3.1, thereby stimulating microbial mineralization...

  9. Distribution of radionuclides in a marine sediment core off the waterspout of the nuclear power plants in Daya Bay, northeastern South China Sea.

    Science.gov (United States)

    Zhou, Peng; Li, Dongmei; Li, Haitao; Fang, Hongda; Huang, Chuguang; Zhang, Yusheng; Zhang, Hongbiao; Zhao, Li; Zhou, Junjie; Wang, Hua; Yang, Jie

    2015-07-01

    A sediment core was collected and dated using (210)Pbex dating method off the waterspout of nuclear power base of Daya Bay, northeastern South China Sea. The γ-emitting radionuclides were analyzed using HPGe γ spectrometry, gross alpha and beta radioactivity as well as other geochemical indicators were deliberated to assess the impact of nuclear power plants (NPP) operation and to study the past environment changes. It suggested that NPP provided no new radioactivity source to sediment based on the low specific activity of (137)Cs. Two broad peaks of TOC, TC and LOI accorded well with the commercial operations of Daya Bay NPP (1994.2 and 1994.5) and LNPP Phase I (2002.5 and 2003.3), implying that the mass input of cooling water from NPP may result into a substantial change in the ecological environment and Daya Bay has been severely impacted by human activities.

  10. Assessment of mercury contamination based on mercury distribution in sediment, macroalgae, and seagrass in the Todos os Santos bay, Bahia, Brazil.

    Science.gov (United States)

    Fostier, Anne H; do N Costa, Fernanda; Korn, Maria das Graças A

    2016-10-01

    The Todos os Santos bay (TSB) is the second largest Brazilian bay. Despite the large number of potential anthropogenic sources of mercury (Hg) in the bay, data on this element in this marine environment are very scarce. Total Hg concentrations were therefore determined in sediment, macroalgae, and seagrass species collected during dry and rainy seasons, from eight locations. In ~45 % of the sediment samples, Hg concentration was two to four times higher than the upper value considered the regional Hg background (15 μg kg(-1)). Geoaccumulation index indicated that Hg contamination was at none to heavily contaminated. In Padina sp., Caulerpa sp., Hypnea sp., and Halodule wrigthii, Hg concentrations ranged from 10.61-297.61, 15.59-74.50, 12.84-158.03, and 4.02-67.25 μg kg(-1), respectively.

  11. In situ microscale variation in distribution and consumption of O2: A case study from adeep ocean margin sediment (Sagami Bay, Japan)

    DEFF Research Database (Denmark)

    Glud, Ronnie Nøhr; Stahl, Henrik; Berg, Peter;

    2009-01-01

    was confined to hot spots. The in situ benthic O2 uptakes, measured during four cruises, reflected a seasonal signal overlying the observed small-scale variability. The annual benthic mineralization balanced ,50% of the estimated pelagic production. However, the central bay is characterized by a significant......A transecting microprofiler documented a pronounced small-scale variation in the benthic O2 concentration at 1450-m water depth (Sagami Bay, Japan). Data obtained during a single deployment revealed that within a sediment area of 190 cm2 the O2 penetration depth varied from 2.6 mm to 17.8 mm...... downslope sediment transport, and mass balance estimates indicate 90% retention of the total organic material reaching the bottom of the central bay....

  12. Early diagenesis and authigenic mineral formation in anoxic sediments of Kau Bay, Indonesia

    NARCIS (Netherlands)

    Middelburg, Jack

    1990-01-01

    Kau Bay (island of Halmahera, Eastern Indonesia) is a 470 m deep basin separated from the Pacific Ocean by a sill that is at present only 40 m below sea-level. The presence of this sill has two major implications. Firstly, during Weichselian time, the sea-level dropped below the depth of the sill, K

  13. Seasonal occurrence of unique sediment plume in the Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Sridhar, P.N.; Ali, M.M.; Vethamony, P.; Babu, M.T.; Ramana, I.V.; Jayakumar, S.

    the Bay of Bengal whose movement is controlled by prevailing currents. The KGB is located in the central part of the east coast of India between 16 degrees 43 minutes, 17 degrees 00 minutes N and 82 degrees 15 minutes, 82 degrees 22 minutes E (Figure 1a...

  14. Curstal evolution and sedimentation history of the Bay of Bengal since the cretaceous

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, D.G.; Krishna, K.S.; Sar, D.

    on three latitudinal profiles) in the Bay of Bengal. The trend of the fracture zones, the locations of the magnetic chron 34, and the Cretaceous Magnetic Quiet Zone suggest that Greater India separated from Antarctica after a period of transform motion...

  15. Sediment sequences and palynology of outer South Bay, Manitoulin Island, Ontario: Connections to Lake Huron paleohydrologic phases and upstream Lake Agassiz events

    Science.gov (United States)

    Lewis, C. F. M.; Anderson, T. W.

    2017-10-01

    South Bay on the southern coast of Manitoulin Island is a fjord-like embayment connected to Lake Huron by a natural narrow gap in the bay's outer sill 6.5-14 m above the lake. A seismic profile, pollen, plant macrofossil, grain size analyses, and other sediment properties of two piston cores from a shallow outer basin of the bay document a 9 m-thick sediment section comprising rhythmically laminated clay under silty clay containing zones with small molluscan shells and marsh detritus. A sandy pebbly layer under soft silty clay mud overlies these sediments. This stratigraphy represents inundation by deep glacial Lake Algonquin followed by the shallowing Post Algonquin series of lakes, and exposure in the early Holocene by 5 Lake Stanley lowstands in the Lake Huron basin separated by 4 Lake Mattawa highstands. Overflow from South Bay in the first lowstand is thought to have eroded the outer sill gap. Marsh environments are inferred to have formed in the bay during subsequent lowstands. The Lake Mattawa highstands are attributed to outburst floods mainly from glacial Lake Agassiz. Palynological evidence of increased spruce occurrence, an apparent regional climate reversal, during the dry pine period is attributed to cold northwest winds from the Lake Superior basin and a lake effect from the Mattawa highstands in the Lake Huron basin. Lake waters transgressed South Bay following the pine period to form the Nipissing shore on Manitoulin Island. Transfer of Lake Huron basin drainage to southern outlets and continued glacioisostatic uplift of the region led to the present configuration of South Bay and Lake Huron.

  16. Three dimensional numerical modeling of Hydrodynamics and sediment transport in the Mississippi River Diversion at West Bay

    Science.gov (United States)

    Sadid, K. M.; Meselhe, E. A.; Roth, B.; Allison, M. A.

    2013-12-01

    The coastal wetlands of Louisiana have been experiencing high rates of land subsidence and erosion for decades. Anthropogenic alterations to the hydrology and geology, powerful hurricanes, and relative sea level rise have caused major coastal land loss in Louisiana. After years of research and discussions, the use of sediment diversions from the Mississippi River to adjacent embayment areas were proposed and further authorized as a solution for land building. To this end, the West Bay diversion (WBD) was constructed in 2003 to restore approximately 9,831 acres of wetlands in the West Bay area under the Coastal Wetlands Planning, Protection, and Restoration Act (CWPPRA). The WBD is located along the right-descending bank of the Mississippi River south of Venice, LA near River Mile (RM) 4.7. The initial size of the channel post-construction was designed to convey 20,000 cubic feet per second (cfs), and over time it was anticipated to support a maximum of 50,000 cfs. This sediment diversion provides an opportunity to examine and analyze the impact of such diversion on the morphology of the river channel, and the retention characteristics and rate of delta growth in the receiving basin. Additionally, the WBD serve as analogue to fully validate morphologic models that could consequently be used to model proposed land building sediment diversions in the Lower Mississippi River. In this study a three-dimensional numerical model is developed for the WBD which includes the main channel of the Mississippi River as well as the receiving basin. The model is being calibrated and validated for hydrodynamics and morphology using detailed field observations. Since 2003 regular monitoring has taken place as per the CWPPRA project guidelines. This includes bathymetric surveys of the receiving basin from 2002 (pre-construction), 2003, 2006, and 2009. A recent monitoring survey has been completed and will be available in the near future. In addition to this monitoring data, the U

  17. Assessment of Bioflocculant Production by Bacillus sp. Gilbert, a Marine Bacterium Isolated from the Bottom Sediment of Algoa Bay

    Directory of Open Access Journals (Sweden)

    Okoh I. Anthony

    2011-07-01

    Full Text Available The bioflocculant-producing potentials of a marine bacteria isolated from the bottom sediment of Algoa Bay was investigated using standard methods. The 16S rDNA sequence analysis revealed 98% similarity to that of Bacillus sp. HXG-C1 and the nucleotide sequence was deposited in GenBank as Bacillus sp. Gilbert with accession number HQ537128. Bioflocculant was optimally produced when sucrose (72% flocculating activity and ammonium chloride (91% flocculating activity were used as sole sources of carbon and nitrogen, respectively; an initial pH 6.2 of the production medium; and Mg2+ as cation. Chemical analysis of the purified bioflocculant revealed the compound to be a polysaccharide.

  18. Thirty years of coral reef change in relation to coastal construction and increased sedimentation at Pelekane Bay, Hawai'i.

    Science.gov (United States)

    Stender, Yuko; Jokiel, Paul L; Rodgers, Kuʻulei S

    2014-01-01

    Coral reefs are being critically impacted by anthropogenic processes throughout the world. Long term monitoring is essential to the understanding of coral reef response to human impacts and the effectiveness of corrective management efforts. Here we reevaluated a valuable coral reef baseline established in Pelekane Bay, Hawai'i during 1976 and subsequently resurveyed in 1996. During this time interval substantial impacts occurred followed by extensive corrective measures. Coral and fish communities showed dramatic declines from 1977 to 1996 due to massive harbor construction and suboptimal land management practices on the watershed. More recently, corrective measures in the form of watershed stabilization and fishing regulations have been implemented. Consequently our 2012 survey reveals that coral cover since 1996 has increased slightly accompanied by a significant increase in fish abundance, diversity, and evenness. This improvement can be attributed to lower fishing pressure since 1996 due to reduced shoreline access, tighter fishing regulations and increased monitoring of legal and illegal fishing activities. Stabilization of the coral community can be attributed partially to reduced sedimentation resulting from watershed restoration that included installation of sediment check dams, control of feral ungulates, controlled grazing and replanting of native vegetation. Insights into the mechanism that removes sediment from reefs was provided by a major storm event and a tsunami that remobilized and flushed out sediment deposits. The increase in herbivorous fishes probably played a role in reducing algal competition in favor of corals. The data suggest that the precipitous reef decline in this area has been arrested and offers support for the corrective actions previously undertaken.

  19. Distributions and Sources of Bulk Organic Matter in Sediments of Five Estuaries in Todos os Santos Bay, Brazil.

    Science.gov (United States)

    Leonel, J.; Hatje, V.

    2016-02-01

    Total organic carbon (TOC), total nitrogen (TN) and their δ13C and δ15N values were determined in cores and surficial sediments to evaluate organic matter contents and sources. Samples were collected along the salinity gradient of five estuaries (Paraguaçu, Subaé, Jaguaribe, São Paulo and Mataripe) of the Todos os Santos Bay (BTS), the second largest bay in Brazil. TOC values ranged from 0.7 to 2.7% and TOC/TN ranged between 1.8 and 8.3. Overall, a slight seaward decrease in %TOC as well as C/N is observed. Values of TOC/TN lower than the Redfield ratios were found in most samples from São Paulo and Mataripe estuaries. This is possibly the result of the anthropogenic impacts caused by oil related activities developed in the region. However, natural causes, such as preferential sorption of inorganic N or bacterially derived organic matters in the sediment, should not be dismissed. Indeed, the influence of inorganic N was also indicated by the low correlation found between TOC and TN values in some estuaries and the positive intercept observed in others, the suggesting that they come from different sources. In general, δ13C values ranged from -26.9 to -20.3‰ and enrichment was observed seaward. Consequently, δ13C has a negatively correlation with the TOC /TN values, except for Subaé River. In all estuaries the δ13Cvalues suggest a mixed marine/terrestrial source of the organic matter with an increase of marine influence towards the river mouth.

  20. Application of 210Pb-derived sedimentation rates and dinoflagellate cyst analyses in understanding Pyrodinium bahamense harmful algal blooms in Manila Bay and Malampaya Sound, Philippines.

    Science.gov (United States)

    Sombrito, E Z; Bulos, A dM; Sta Maria, E J; Honrado, M C V; Azanza, Rhodora V; Furio, Elsa F

    2004-01-01

    The number of areas affected by toxic harmful algal bloom (HAB) in the Philippines has been increasing since its first recorded occurrence in 1983. Thus far, HAB has been reported in about 20 areas in the Philippines including major fishery production areas. The HAB-causing organism (Pyrodinium bahamense var. compressum) produces a cyst during its life cycle. Pyrodinium cysts which are deposited in the sediment column may play a role in initiating a toxic bloom. 210Pb-derived sedimentation rate studies in the two important fishing grounds of Manila Bay and Malampaya Sound, Palawan have shown that Pyrodinium cysts may have been present in the sediment even before the first recorded toxic algal bloom in these areas. High sedimentation rates (approximately 1 cm/year) have been observed in the northern and western parts of Manila Bay. The results indicate that the sedimentation processes occurring in these bays would require subsurface cyst concentration analysis in evaluating the potential of an area to act as seed bed.

  1. Application of {sup 210}Pb-derived sedimentation rates and dinoflagellate cyst analyses in understanding Pyrodinium bahamense harmful algal blooms in Manila Bay and Malampaya Sound, Philippines

    Energy Technology Data Exchange (ETDEWEB)

    Sombrito, E.Z. E-mail: ezsombrito@pnri.dost.gov.ph; Bulos, A.M.; Sta Maria, E.J.; Honrado, M.C.V.; Azanza, Rhodora V.; Furio, Elsa F

    2004-07-01

    The number of areas affected by toxic harmful algal bloom (HAB) in the Philippines has been increasing since its first recorded occurrence in 1983. Thus far, HAB has been reported in about 20 areas in the Philippines including major fishery production areas. The HAB-causing organism (Pyrodinium bahamense var. compressum) produces a cyst during its life cycle. Pyrodinium cysts which are deposited in the sediment column may play a role in initiating a toxic bloom. {sup 210}Pb-derived sedimentation rate studies in the two important fishing grounds of Manila Bay and Malampaya Sound, Palawan have shown that Pyrodinium cysts may have been present in the sediment even before the first recorded toxic algal bloom in these areas. High sedimentation rates (approximately 1 cm/year) have been observed in the Northern and Western parts of Manila Bay. The results indicate that the sedimentation processes occurring in these bays would require subsurface cyst concentration analysis in evaluating the potential of an area to act as sea bed.

  2. Seasonal, Spatial Distribution and Ecological Risk Assessment of Heavy Metals in Surface Sediments from a Watershed Area in Gonghu Bay in Taihu Lake, China

    Directory of Open Access Journals (Sweden)

    Peifang Wang

    2014-01-01

    Full Text Available Surface sediments from five stations within Gonghu Bay in Taihu Lake, China, were sampled for seasonal and spatial metal contamination analysis variations and ecological risks assessment from April 2009 to January 2010. The Contamination Factor (CF and geo-accumulation index (Igeo indicated that the sediments in Gonghu Bay ranged from unpolluted to moderately polluted, except for Cd. The one-way ANOVA analysis results showed that the Pb, Zn, Cr, and Cu concentrations were higher at station 3 (lake inlet and the Cr, Pb, and Zn concentrations were significantly higher in the spring. Additionally, using BCR¡¦s sequential extraction, the results showed that the fractionated metals Zn and Cd were observed as bioavailable fractions in the sediments, which could have potential moderate mobility in the water system. There was a significant increase in the bioavailable form during winter. The ratio of secondary and primary phrase (RSP decreased according to the order Zn > Cu > Ni > Pb > Cd > Cr. Finally, these results indicated that the sediments of Gonghu Bay were polluted by Cd, Zn, and Cu, which provides a scientific basis for effectively protecting sediments in watershed areas from long-term heavy metal accumulation.

  3. Distribution of clay minerals in marine sediments off Chennai, Bay of Bengal, India: Indicators of sediment sources and transport processes .

    Digital Repository Service at National Institute of Oceanography (India)

    Veerasingam, S.; Venkatachalapathy, R.; Ramkumar, T.

    in a Perkin Elmer RX1 spectrometer. Pellets were scanned at room temperature (25°C) in the 4,000 – 400 cm –1 spectral range. To improve the signal to noise ratio for each spectrum, 100 interferograms with a spectral resolution of ±4 cm-1 were averaged... similar vibrational reflectance spectra in the middle region of the infrared spectrum and Fig. 2 shows assembled FTIR spectra of some selected marine sediment samples. The band from 3,600 to 3,650 cm-1 is attributed to n (O–H) vibrations of hydroxyl...

  4. 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...

  5. Pore water studies reef flat sediments, Kaneohe Bay, Oahu, HI (NODC Accession 0000271)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Geochemical behavior of the upper 70 cm of permeable reef flat sediments on Checker Reef, Oahu, Hawaii was examined using spatial and temporal changes in pore water...

  6. Trace metal levels in nearshore sediments close to industrial discharges off Cuddalore (Bay of Bengal)

    Digital Repository Service at National Institute of Oceanography (India)

    Joseph, T.; Balachandran, K.K.; Nair, M.; Das, V.K.; Nair, K.K.C.; Paimpillii, J.S.

    Trace metals in the sediment and in the overlying water column along with texture characteristics in the vicinity of industrial discharges at Cuddallore were analyzed, covering the seasonal changes to identify probable anthropogenic influence...

  7. Fluxes of material in the Arabian Sea and Bay of Bengal - Sediment trap studies

    Digital Repository Service at National Institute of Oceanography (India)

    Ramaswamy, V.; Nair, R.R.

    In order to investigate how monsoons influence biogeochemical fluxes in the ocean, twelve time-series sediment traps were deployed at six locations in the northern Indian Ocean. In this paper we present particle flux data collected during May 1986...

  8. 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...

  9. Relationship between metal enrichments and a biological adverse effects index in sediments from Todos Santos Bay, northwest coast of Baja California, México.

    Science.gov (United States)

    Muñoz-Barbosa, A; Gutiérrez-Galindo, E A; Daesslé, L W; Orozco-Borbón, M V; Segovia-Zavala, J A

    2012-02-01

    In 1992 and 2004, heavy metals concentrations were measured in surficial sediments from Todos Santos Bay, located in Ensenada, Baja California, Mexico. The aim was to search for relationships between metal enrichment factors and a biological adverse effects index. Unlike Ni, the elements Cd, Cu and Zn showed significant correlations (p5.5 and >1.5, respectively, in order for the sediments to be considered toxic. In general, data showed that most of the metal concentrations in Todos Santos Bay sediments could not cause adverse effects to biota. Only Ensenada's harbor and the zone next to a dredging dumping site showed metal enrichments that could be toxic. Copyright © 2011 Elsevier Ltd. All rights reserved.

  10. Instrument packages to study long-term sediment transport processes in a shallow bay

    Science.gov (United States)

    Strahle, William J.; Martini, Marinna A.; Davis, Ray E.

    1994-01-01

    Pressure and near-surface and near-bottom measurements of current, temperature, salinity and light transmission were required in Mobile Bay, a 3 m deep estuary on the Gulf of Mexico. This environment presented several obstacles to obtaining long term observations. Boat traffic, soft estuary bottom, heavy biofouling, rapid sample rates and large data storage were overcome by using instrumentation techniques that are applicable to other estuary systems. Nearly two years of continuous data was collected.

  11. Heavy metal determination by X-rays spectrometry in superficial sediments at Havana Bay

    Energy Technology Data Exchange (ETDEWEB)

    Gelen, Alina; Izquierdo, Walter; Lopez, Neivy; Corrales, Yasser; Casanova, Amaya O.; Diaz, Oscar; Manso, Maria V.; D' Alessandro, Katia [Institute for Applied Sciences and Technology, Havana (Cuba)], E-mail: alina@instec.cu; Reyes, Enma; Toledo, Carlos [Central Laboratory Criminology, Havana (Cuba); Beltran, Jesus; Perez, Marlen; Ramirez, Marta [Engineering Centre for Environmental Management of Bays and Coasts, Havana (Cuba)], E-mail: beltran@cimab.transnet.cu; Soto, Jesus [Universidad de Cantabria, Santander (Spain)], E-mail: sotoj@unican.es

    2007-07-01

    Havana Bay is a typical bag-type located in the Western-North Coast of the Republic of Cuba. Since 1980 it has been the object of a study for sea bottom rehabilitation and improvement of quality of the waters, where the final objective will be the recovery of the coastal and marine ecosystem. Thirteen surface samples of the Havana Bay (Cuba) were collected and analysed by X-Rays spectrometry. Some majority elements (Si, Ca, K, Na, S, Cl, Al, Fe, Mg, C and O) were measured by scanning electron microscopy (SEM) coupled with microanalysis to perform geomorphologic analysis. Nine elements (Ca, Fe, Ti, Mn, Cu, Zn, Sr, Zr and Pb) have been measured using an Energy Dispersive X-Ray Fluorescence (EDXRF) with a Si(Li) detector. Multivariate statistical was used for the analysis. The concentration levels showed this bay as the most polluted in Cuba. The highest contents of Cu, Zn and Pb were obtained in Atares and Marimelena Cove; these elements are indicators of urban as well as industrial pollution. (author)

  12. Characterization of selected bed-sediment-bound organic and inorganic contaminants and toxicity, Barnegat Bay and major tributaries, New Jersey, 2012

    Science.gov (United States)

    Romanok, Kristin M.; Reilly, Timothy J.; Lopez, Anthony R.; Trainor, John J.; Hladik, Michelle L.; Stanley, Jacob K.; Farrar, Daniel

    2014-01-01

    A study of bed-sediment toxicity and organic and inorganic contaminants was conducted by the U.S. Geological Survey (USGS) in cooperation with the New Jersey Department of Environmental Protection (NJDEP). Bed-sediment samples were collected once from 22 sites in Barnegat Bay and selected major tributaries during August–September 2012 and analyzed for toxicity and a suite of organic and inorganic contaminants by the USGS and the U.S. Army Corps of Engineers. Sampling sites were selected to coincide with an existing water-quality monitoring network used by the NJDEP and others in order to evaluate water-quality conditions in Barnegat Bay and the surrounding watershed. Two of the 22 sites are reference sites and are within or adjacent to the study area; bed-sediment samples from reference sites allow for comparisons of results for the Barnegat Bay watershed to results from less affected settings within the region. Toxicity testing was conducted by exposing the estuarine amphipod Leptocheirus plumulosus and the freshwater amphipod Hyalella azteca to sediments for 28 days, and the percent survival, difference in biomass, and individual dry weights were measured. Reproductive effects also were evaluated for estuarine samples. Bed-sediment samples from four sites within Barnegat Bay were subjected to a toxicity identification evaluation to determine probable causes of toxicity. Samples were analyzed for a suite of 94 currently-used pesticides, 21 legacy pesticides, 24 trace elements, 40 polycyclic aromatic hydrocarbons, 7 polychlorinated biphenyls (PCBs) as Arochlor mixtures, and 145 individual PCB congeners. Concentrations of detected compounds were compared to sediment-quality guidelines, where appropriate.

  13. The effect of physical and chemical parameters on the macroinfaunal community structure of San Vicente bay, Chile Efectos de parámetros físicos y químicos en la estructura comunitaria de la macroinfauna en la bahía de San Vicente, Chile

    Directory of Open Access Journals (Sweden)

    ROCÍO A. SIEMENS

    2001-06-01

    Full Text Available San Vicente bay is a heavily industrialised bay located in central Chile, which has a sand beach extending from an area of recreational use in the south to an area of industrial use and discharge in the north. A survey of the macrofauna in the intertidal zone revealed a non-homogeneous distribution; a maximum of five invertebrate species were found with all five only occurring in one of six transects down the beach. The density ranged from 0 to 188 individuals m-2, with the highest density at the recreational end. The most common species, Emerita analoga (Stimpson, was chosen to study the macrofaunal response to beach morphodynamics, physicochemical parameters and metal concentrations. The E. analoga distribution was not significantly correlated with the results of the physicochemical analyses of interstitial water (pH, temperature, salinity and oxygen concentrations. However, oxygen concentrations decreased to 3 ml O2 l-1 in the lower intertidal closest to the recreational area where the highest numbers of intertidal macrofauna were observed. Analyses of 12 metals in the sediments showed three distinct distribution patterns across the beach in which the metals could be classified: a representative metal was chosen for each distribution. The concentration of tin ranged from 3.4 to 11.58 mg g-1DW sediment, representing the `wave' pattern. The concentration of cadmium ranged from 0 to 0.23 mg g-1DW sediment, representing the `banded' pattern. The concentration of chromium ranged from 1.97 to 3.18 mg g-1DW sediment, representing the `intermediate' pattern of metal distribution. The E. analoga distribution was not significantly correlated with the concentrations of any single metal, although multivariate statistical analysis indicated that Sn and Fe had the largest negative effect and Mn had the largest positive one. The distribution of E. analoga across the sandy beach of San Vicente bay was significantly correlated with the relative tidal range

  14. Acute sedimentation response to rainfall following the explosive phase of the 2008-2009 eruption of Chaitén volcano, Chile

    Science.gov (United States)

    Pierson, Thomas C.; Major, Jon J.; Amigo, Álvaro; Moreno, Hugo

    2013-01-01

    The 10-day explosive phase at the start of the 2008–2009 eruption of Chaitén volcano in southern Chile (42.83°S, 72.65°W) blanketed the steep, rain-forest-cloaked, 77-km2 Chaitén River drainage basin with 3 to >100 cm of tephra; predominantly fine to extremely fine rhyolitic ash fell during the latter half of the explosive phase. Rain falling on this ash blanket within days of cessation of major explosive activity generated a hyperconcentrated-flow lahar, followed closely by a complex, multi-day, muddy flood (streamflow bordering on dilute hyperconcentrated flow). Sediment mobilized in this lahar-flood event filled the Chaitén River channel with up to 7 m of sediment, buried the town of Chaitén (10 km downstream of the volcano) in up to 3 m of sediment, and caused the lower 3 km of the channel to avulse through the town. Although neither the nature nor rate of the sedimentation response is unprecedented, they are unusual in several ways: (1) Nearly 70 percent of the aggradation (almost 5 m) in the 50–70-m-wide Chaitén River channel was caused by a lahar, triggered by an estimated 20 mm of rainfall over a span of about 24 h. An additional 2 m of aggradation occurred in the next 24–36 h. (2) Direct damage to the town was accomplished by the sediment-laden water-flood phase of the lahar-flood event, not the lahar phase. (3) The volume of sediment eroded from hillslopes and delivered to the Chaitén River channel was at least 3–8 × 106 m3—roughly 15–40 % of the minimum tephra volume that mantled the Chaitén River drainage basin. (4) The acute sedimentation response to rainfall appears to have been due to the thickness and fineness of the ash blanket (inhibiting infiltration of rain) and the steepness of the basin’s hillslopes. Other possible factors such as the prior formation of an ash crust, development of a hydrophobic surface layer, or large-scale destruction of rain-intercepting vegetation did not play a role.

  15. Spatial distribution of pollen grains and spores in surface sediments of Guanabara Bay, Rio de Janeiro, Brazil

    Directory of Open Access Journals (Sweden)

    Cintia F. Barreto

    2012-09-01

    Full Text Available Aiming to investigate the deposition of pollen grains and spores in Guanabara Bay, Rio de Janeiro State, 61 surface sediment samples were analyzed. The results showed that the current deposition of palynomorphs in surface sediments of Guanabara Bay represents the regional vegetation of this hydrographic basin. The differential distribution of palynomorphs followed a pattern influenced by bathymetry, tidal currents speed, discharge of numerous rivers, and by human activity. The dominance of representatives of Field Vegetation reflects the changes of the original flora caused by intense human activities in the region. The continued presence and richness of pollen types of rain forest in the samples indicates that their source area might be the vegetation from riparian border of rivers in the western sector of the Bay, where the mangrove vegetation is being preserved. The large amount of damaged palynomorphs may be related to abrasion that occurs during river transport, indicating removal or reworking from their areas of origin.Com objetivo de investigar a deposição dos grãos de pólen e esporos na Baía de Guanabara, Estado do Rio de Janeiro, 61 amostras de sedimentos superficiais foram analisadas. Os resultados mostraram que a deposição atual dos palinomorfos nos sedimentos superficiais da Baía de Guanabara representa a vegetação regional de sua bacia hidrográfica. A distribuição diferencial dos palinomorfos seguiu um padrão influenciado pela batimetria, velocidade das corretes de marés, descarga dos numerosos rios e pela atividade humana. A dominância dos taxa representantes da Vegetação Campestre reflete as mudanças da flora original causadas por intensas atividades humanas na região. A presença contínua e a grande riqueza de tipos polínicos da Floresta Ombrófila nas amostras, indica que a área fonte pode ser a vegetação das bordas dos rios do setor oeste da Baía, onde a vegetação de mangue está sendo preservada. A

  16. Environmental magnetic and geochemical characteristics of Chennai coastal sediments, Bay of Bengal, India

    Indian Academy of Sciences (India)

    R Venkatachalapathy; S Veerasingam; N Basavaiah; T Ramkumar; K Deenadayalan

    2011-10-01

    In this study, environmental magnetic, heavy metal and statistical analyses were conducted on 21 surface sediments collected from Chennai coast, India, to examine the feasibility of heavy metal pollution using magnetic susceptibility. The Chennai coastal sediment samples are dominated by ferrimagnetic minerals corresponding to magnetite-like minerals. The percentage of frequency dependent magnetic susceptibility reflects the presence of super-paramagnetic/single domain magnetic minerals in Chennai harbour, Cooum and Adayar rivers sediments. High pollution load index in sample E1, E2, CH7, C11, C12 and A16 is mainly due to anthropogenic activities such as, harbour activities, Cooum and Adayar rivers input and industrial effluent. Factor analysis shows that the magnetic concentration dependent parameters (, ARM and SIRM) covary with the heavy metal concentrations, suggesting that the input of magnetic minerals and heavy metals in Chennai coastal sediments are derived from the same anthropogenic sources. Strong correlation obtained between pollution load index (PLI) and concentration dependent parameters (, ARM and SIRM) for the polluted samples with magnetic susceptibility excess of 50 × 10−8 m3kg−1. Significant correlations between heavy metals and magnetic susceptibility point out the potential of magnetic screening/monitoring for simple and rapid proxy indicator of heavy metal pollution in marine sediments.

  17. Assessing heavy metal pollution in the recent bottom sediments of Mabahiss Bay, North Hurghada, Red Sea, Egypt.

    Science.gov (United States)

    Attia, Osama E A; Ghrefat, Habes

    2013-12-01

    Thirty-nine samples of recent bottom sediments were collected from Mabahiss Bay, north of Hurghada City, Red Sea, Egypt. The collected samples were subjected to a total digestion technique and analyzed by absorption spectrometer for metals including Pb, Zn, Cd, Ni, Co, Cu, and Mn. Concentration data were processed using correlation analysis, principal component analysis, and hierarchical cluster analysis. Multivariate statistical analysis classified heavy metals in the study area into different groups. The pollution level attributed to these metals was evaluated using geoaccumulation index and contamination factor in order to determine anthropogenically derived sediment contamination. The results of both geoaccumulation index and contamination factor results reveal that the study area is not contaminated with respect to Zn, Ni, Cu, and Mn; uncontaminated to moderately contaminate with Pb; and moderately to strongly contaminate with Cd. The high contents of Pb, Cd, and Co in the study area result from various anthropogenic activities including dredging, land filling, localized oil pollution, using of antifouling and anticorrosive paints from fishing and tourist boats, and sewage discharging from various sources within the study area.

  18. Quantifying the erosion processes and land-uses which dominate fine sediment supply to Moreton Bay, Southeast Queensland, Australia.

    Science.gov (United States)

    Wallbrink, Peter J

    2004-01-01

    In this paper, the contributions from the three major erosion sources in the catchments of Moreton Bay are quantified, specifically for the erosion sources are classified as (i) sheet erosion from cultivated land, (ii) sheet erosion from uncultivated land, and (iii) subsoil erosion from gullies and channels. The catchments were the Brisbane and Logan rivers as well as the coastal catchments. A GIS based analysis of erosion risk was used to define areas of high erosion potential in each of the erosion source types. Radionuclide concentrations of 137Cs and 226Ra were measured on the soils from these areas and then compared to concentrations on the same size fraction on deposited sediments within the rivers. A mixing model was then used to calculate the contributions from the different sources to the sediments. The contributions in the Brisbane and Logan catchments were found to be subsoil erosion (approximately 66 +/- 10%); sheet erosion from cultivated lands 33 +/- 10% and sheet erosion of uncultivated land 1 +/- 10%. Surface and subsoil erosion contributions from the coastal catchments were found to be variable.

  19. Mercury methylation by a microbial community from sediments of the Adour Estuary (Bay of Biscay, France)

    Energy Technology Data Exchange (ETDEWEB)

    Duran, R. [Equipe Environnement et Microbiologie, Institut Pluridisciplinaire de Recherche sur l' Environnement et les Materiaux, UMR CNRS 5254, Universite de Pau et des Pays de l' Adour, Avenue de l' Universite, IBEAS BP1155, 64013 Pau Cedex (France)], E-mail: robert.duran@univ-pau.fr; Ranchou-Peyruse, M.; Menuet, V. [Equipe Environnement et Microbiologie, Institut Pluridisciplinaire de Recherche sur l' Environnement et les Materiaux, UMR CNRS 5254, Universite de Pau et des Pays de l' Adour, Avenue de l' Universite, IBEAS BP1155, 64013 Pau Cedex (France); Monperrus, M.; Bareille, G. [Equipe Chimie Analytique Bio-Inorganique et Environnement, Institut Pluridisciplinaire de Recherche sur l' Environnement et les Materiaux, UMR CNRS 5254, Universite de Pau et des Pays de l' Adour, 64013 Pau Cedex (France); Goni, M.S.; Salvado, J.C. [Equipe Environnement et Microbiologie, Institut Pluridisciplinaire de Recherche sur l' Environnement et les Materiaux, UMR CNRS 5254, Universite de Pau et des Pays de l' Adour, Avenue de l' Universite, IBEAS BP1155, 64013 Pau Cedex (France); Amouroux, D. [Equipe Chimie Analytique Bio-Inorganique et Environnement, Institut Pluridisciplinaire de Recherche sur l' Environnement et les Materiaux, UMR CNRS 5254, Universite de Pau et des Pays de l' Adour, 64013 Pau Cedex (France); Guyoneaud, R. [Equipe Environnement et Microbiologie, Institut Pluridisciplinaire de Recherche sur l' Environnement et les Materiaux, UMR CNRS 5254, Universite de Pau et des Pays de l' Adour, Avenue de l' Universite, IBEAS BP1155, 64013 Pau Cedex (France); Donard, O.F.X. [Equipe Chimie Analytique Bio-Inorganique et Environnement, Institut Pluridisciplinaire de Recherche sur l' Environnement et les Materiaux, UMR CNRS 5254, Universite de Pau et des Pays de l' Adour, 64013 Pau Cedex (France)] (and others)

    2008-12-15

    In order to study the influence of microorganisms on the mercury biogeochemistry, the metal content and the structure of microbial communities were determined in sediments from stations along the Adour Estuary. The comparison of the bacterial communities and their distribution in function of the environmental parameters by Canonical Correspondence Analysis (CCA) revealed the influence of metals on the bacterial communities structure. Sediments where the bacterial communities are mostly influenced by methylmercury were incubated in slurries with or without mercury, under oxic and anoxic conditions. Methylmercury production was detected in the anoxic biotic slurries with a net methylation yield of 0.3% after 24 h. CCA based on T-RFLP profiles revealed the impact of mercury addition on the bacterial communities structure. In addition, 17 bacterial strains, mainly sulphate-reducing bacteria involved in mercury methylation, were isolated and identified. - Role of oxic/anoxic cycles and microbial activities on the methylmercury formation in Adour (France) estuarine sediments.

  20. Wave Energy Converter (WEC) Array Effects on Wave Current and Sediment Circulation: Monterey Bay CA.

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, Jesse D.; Jones, Craig; Magalen, Jason

    2014-09-01

    The goal s of this study were to develop tools to quantitatively characterize environments where wave energy converter ( WEC ) devices may be installed and to assess e ffects on hydrodynamics and lo cal sediment transport. A large hypothetical WEC array was investigated using wave, hydrodynamic, and sediment transport models and site - specific average and storm conditions as input. The results indicated that there were significant changes in sediment s izes adjacent to and in the lee of the WEC array due to reduced wave energy. The circulation in the lee of the array was also altered; more intense onshore currents were generated in the lee of the WECs . In general, the storm case and the average case show ed the same qualitative patterns suggesting that these trends would be maintained throughout the year. The framework developed here can be used to design more efficient arrays while minimizing impacts on nearshore environmen ts.

  1. Comparison of two regression-based approaches for determining nutrient and sediment fluxes and trends in the Chesapeake Bay watershed

    Science.gov (United States)

    Moyer, Douglas; Hirsch, Robert M.; Hyer, Kenneth

    2012-01-01

    Nutrient and sediment fluxes and changes in fluxes over time are key indicators that water resource managers can use to assess the progress being made in improving the structure and function of the Chesapeake Bay ecosystem. The U.S. Geological Survey collects annual nutrient (nitrogen and phosphorus) and sediment flux data and computes trends that describe the extent to which water-quality conditions are changing within the major Chesapeake Bay tributaries. Two regression-based approaches were compared for estimating annual nutrient and sediment fluxes and for characterizing how these annual fluxes are changing over time. The two regression models compared are the traditionally used ESTIMATOR and the newly developed Weighted Regression on Time, Discharge, and Season (WRTDS). The model comparison focused on answering three questions: (1) What are the differences between the functional form and construction of each model? (2) Which model produces estimates of flux with the greatest accuracy and least amount of bias? (3) How different would the historical estimates of annual flux be if WRTDS had been used instead of ESTIMATOR? One additional point of comparison between the two models is how each model determines trends in annual flux once the year-to-year variations in discharge have been determined. All comparisons were made using total nitrogen, nitrate, total phosphorus, orthophosphorus, and suspended-sediment concentration data collected at the nine U.S. Geological Survey River Input Monitoring stations located on the Susquehanna, Potomac, James, Rappahannock, Appomattox, Pamunkey, Mattaponi, Patuxent, and Choptank Rivers in the Chesapeake Bay watershed. Two model characteristics that uniquely distinguish ESTIMATOR and WRTDS are the fundamental model form and the determination of model coefficients. ESTIMATOR and WRTDS both predict water-quality constituent concentration by developing a linear relation between the natural logarithm of observed constituent

  2. Nitrogen cycling in a deep ocean margin sediment (Sagami Bay, Japan)

    DEFF Research Database (Denmark)

    Glud, Ronnie Nøhr; Thamdrup, C.; Stahl, H

    2009-01-01

    On the basis of in situ NO3- microprofiles and chamber incubations complemented by laboratory-based assessments of anammox and denitrification we evaluate the nitrogen turnover of an ocean margin sediment at 1450-m water depth. In situ NO3- profiles horizontally separated by 12 mm reflected highly...... metabolism for 12-52 d, contributed only to a minor extent to the overall N-2 production. The microbial activity in the surface sediment is a net nutrient sink of similar to 1.1 mmol N m(-2) d(-1), which aligns with many studies performed in coastal and shelf environments. Continental margin areas can act...

  3. Nutrient and suspended-sediment trends, loads, and yields and development of an indicator of streamwater quality at nontidal sites in the Chesapeake Bay watershed, 1985-2010

    Science.gov (United States)

    Langland, Michael; Blomquist, Joel; Moyer, Douglas; Hyer, Kenneth

    2012-01-01

    The U.S. Geological Survey (USGS) updates information on loads of, and trends in, nutrients and sediment annually to help the Chesapeake Bay Program (CBP) investigators assess progress toward improving water-quality conditions in the Chesapeake Bay and its watershed. CBP scientists and managers have worked since 1983 to improve water quality in the bay. In 2010, the U.S. Environmental Protection Agency (USEPA) established a Total Maximum Daily Load (TMDL) for the Chesapeake Bay. The TMDL specifies nutrient and sediment load allocations that need to be achieved in the watershed to improve dissolved oxygen, water-clarity, and chlorophyll conditions in the bay. The USEPA, USGS, and state and local jurisdictions in the watershed operate a CBP nontidal water-quality monitoring network and associated database that are used to update load and trend information to help assess progress toward reducing nutrient and sediment inputs to the bay. Data collected from the CBP nontidal network were used to estimate loads and trends for two time periods: a long-term period (1985-2010) at 31 "primary" sites (with storm sampling) and a 10-year period (2001-10) at 33 primary sites and 16 "secondary" sites (without storm sampling). In addition, loads at 64 primary sites were estimated for the period 2006 to 2010. Results indicate improving flow-adjusted trends for nitrogen and phosphorus for 1985 to 2010 at most of the sites in the network. For nitrogen, 21 of the 31 sites showed downward (improving) trends, whereas 2 sites showed upward (degrading) trends, and 8 sites showed no trends. The results for phosphorus were similar: 22 sites showed improving trends, 4 sites showed degrading trends, and 5 sites indicated no trends. For sediment, no trend was found at 40 percent of the sites, with 10 sites showing improving trends and 8 sites showing degrading trends. The USGS, working with CBP partners, developed a new water-quality indicator that combines the results of the 10-year trend

  4. Variabilidad estacional de cadmio en un sistema de surgencia costera del norte de Chile (Bahía Mejillones del Sur, 23° S Seasonal variability of cadmium in a coastal upwelling system off northern Chile (Mejillones bay, 23° S

    Directory of Open Access Journals (Sweden)

    JORGE VALDÉS

    2006-12-01

    observada en esta razón pueden ser explicados ya sea por una mayor eficiencia en la remoción de PO4 que de Cadmio en las aguas superficiales o una mayor remineralización de cadmio en las aguas subsuperficialesTotal and dissolved cadmium were measured from surface to 100 m water depth, between June 2002 and April 2003, in Mejillones bay. Total and dissolved cadmium range concentration was 0.41-10.7 and 0.08-1.61 nM, respectively. Cadmium profiles and water structure were used to study seasonal variability patterns of this metal in this upwelling system. Oceanographic conditions during this period correspond to a normal (non-El Niño year. Water masses present in this bay correspond to subantartic superficial water, subtropical superficial water and Equatorial subsuperficial water with different degree of mixture and stratification during sampling period. Cadmium profiles showed a classic nutrient-type distribution. Whereas some differences in this profiles could be attributed to a water masses mixing condition into the bay. Multivariate analysis indicates that temporal cadmium variations were associated with chlorophyll-a concentration and temperature fluctuation, indicating that, at this temporal resolution, phytoplanktonic biomass production is the principal factor controlling cadmium concentration in surface waters of Mejillones bay. By other hand, in spite of cadmium being a redox-sensitive metal, any significant influence of dissolved oxygen on this metal were founded, thus microxic condition of bottom water of Mejillones bay is not the principal factor that promotes cadmium flux to the sediments. Cd/PO4 ratio is in agreement with normal values reported for the Chilean coast, and its low values, compared with the northeast Pacific coast, can be explained either by the fact that PO4 is more efficiently removed than cadmium from the surface layer, or that cadmium remineralization is occurring much faster than in the case of PO4

  5. Textural and geochemical characteristics of off shore sediment of North Bay of Bengal:A statistical approach for marine metal pollution

    Institute of Scientific and Technical Information of China (English)

    Sanghamitra Palleyi; Sabnam Banoo; Rabi Narayan Kar; Chitta Ranjan Panda

    2015-01-01

    abstract Metal pollution study on sediments of North Bay of Bengal sediments presented in this paper is based on existing Lithostratigraphy of upstream, mineralogy and geochemical analysis of 42 sediment samples. The statistical analysis identifies the metal pollution as well as its apparent source in the off shore regions. Samples were analyzed for grain size, organic content and heavy metals (Fe, Mn, Cr, Cu, Ni, Pb, Cd, Zn and Co) using the sequential extraction method to evaluate geochemical processes and pollution load. In an effort to surmise anthropogenic input, several approaches including classification by quantitative indexes such as enrichment factor, contamination factor, degree of pollution, pollution load index and geo accumulation index, were attempted. Metal speciation results indicate high%of Cd in exchangeable fraction of Mahanadi transect sediments where as a considerable amount of oxidizable fraction of Cr was detected at Dhamra. Quantitative indexes place North Bay of Bengal under moderately polluted zone due to high level of Cd. Normalization of metals to Fe indicated relatively high enrichment factors for Cd and Cr. Factor analysis identified seven possible types of geochemical associations where sediment pH plays a major role for the heavy metal mobility. The higher Cd concentration in exchangeable fraction as well as the higher EF for Cd and Cr present in sediment may pose a risk of secondary water pollution under slightest disturbance in the geo-chemistry of sediments. Comparison study with available data of near costal zones and upstream stratigraphy revealed that open cast mining, overburden dumping, mineral based industrial effluents were the major source of pollution for catchment area contamination. Bay of Bengal is likely to face a serious threat of metal pollution with the present deposition rates unless rigorous pollution control norms are applied.

  6. 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

  7. Are WWTPs effluents responsible for acute toxicity? Seasonal variations of sediment quality at the Bay of Cádiz (SW, Spain).

    Science.gov (United States)

    Maranho, L A; Garrido-Pérez, M C; Baena-Nogueras, R M; Lara-Martín, P A; Antón-Martín, R; DelValls, T A; Martín-Díaz, M L

    2015-03-01

    Adverse effects of wastewater treatment plants (WWTPs) on sediment quality at the Bay of Cádiz (SW, Spain) were evaluated by a battery of acute bioassays and chemical contamination. Five sites directly affected by WWTPs effluents and one control site were chosen. Results evidenced clear deterioration of ecological sediment quality parameters and possible effects on aquatic communities towards WWTPs areas. Acute toxicity and chemical contamination varied significantly across the studied sites and differed between winter and summer seasons. The Bay of Cádiz is contaminated by PAHs, metals, detergents (SAS) and pharmaceutical products. Principal Component Analyses indicated metals, SAS and pharmaceutical products as the major environmental stresses. Sea-urchin embryo-larval and microalgae growth rate were the most sensitive bioassays to evaluate resuspension of contaminants (elutriate) from bulk sediment. Amphipods mortality and Microtox(®) solid phase test bioassays were recommended to evaluate bulk sediment quality. Therefore, the use of multiple-bioassays, sensitive to sediment pollution, may provide complementary information to diagnose environmental factors that can impair aquatic communities. The battery of bioassays is recommended to assess and monitor marine sediments directly affected by a mixture of contaminants released from WWTPs.

  8. Using GOCI Retrieval Data to Initialize and Validate a Sediment Transport Model for Monitoring Diurnal Variation of SSC in Hangzhou Bay, China

    Directory of Open Access Journals (Sweden)

    Xuefei Yang

    2016-03-01

    Full Text Available The diurnal variation of the suspended sediment concentration (SSC in Hangzhou Bay, China has been investigated using remotely-sensed SSC derived from the Geostationary Ocean Color Imager (GOCI in combination with a coupled hydrodynamic-ecological model for regional and shelf seas (COHERENS. The SSC maps were inferred through a UV-AC atmospheric correction algorithm and an empirical inversion algorithm from the GOCI Level-1B data. The sediment transport model was initialized from maps of the GOCI-derived SSC and the model results were validated through a comparison with remotely-sensed data. The comparison demonstrated that the model results agreed well with the observations. The relationship between SSC distribution and hydrodynamic conditions was analyzed to investigate the sediment transport dynamics. The model’s results indicate that the action of tidal currents dominate the sediment deposition and re-suspension in the coastal waters of the East China Sea. This is especially the case in Hangzhou Bay where the tidal currents are strongest. The satellite-derived sediment data product can not only dramatically improve the specification of the initial conditions for the sediment model, but can also provide valuable information for the model validation, thereby improving the model’s overall performance.

  9. Characterization of organic matter in sediment cores of the Todos os Santos Bay, Bahia, Brazil, by elemental analysis and 13C NMR.

    Science.gov (United States)

    Costa, A B; Novotny, E H; Bloise, A C; de Azevedo, E R; Bonagamba, T J; Zucchi, M R; Santos, V L C S; Azevedo, A E G

    2011-08-01

    The impact of human activity on the sediments of Todos os Santos Bay in Brazil was evaluated by elemental analysis and 13C Nuclear Magnetic Resonance (13C NMR). This article reports a study of six sediment cores collected at different depths and regions of Todos os Santos Bay. The elemental profiles of cores collected on the eastern side of Frades Island suggest an abrupt change in the sedimentation regime. Autoregressive Integrated Moving Average (ARIMA) analysis corroborates this result. The range of depths of the cores corresponds to about 50 years ago, coinciding with the implantation of major onshore industrial projects in the region. Principal Component Analysis of the 13C NMR spectra clearly differentiates sediment samples closer to the Subaé estuary, which have high contents of terrestrial organic matter, from those closer to a local oil refinery. The results presented in this article illustrate several important aspects of environmental impact of human activity on this bay. Copyright © 2011 Elsevier Ltd. All rights reserved.

  10. Concentrations and compositions of organochlorine contaminants in sediments, soils, crustaceans, fishes and birds collected from Lake Tai, Hangzhou Bay and Shanghai city region, China

    Energy Technology Data Exchange (ETDEWEB)

    Nakata, Haruhiko [Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555 (Japan)]. E-mail: nakata@sci.kumamoto-u.ac.jp; Hirakawa, Yuko [Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555 (Japan); Kawazoe, Masahiro [Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555, (Japan); Nakabo, Tetsuji [Kyoto University Museum, Kyoto University, Sakyo-ku, Kyoto 606-8501 (Japan); Arizono, Koji [Faculty of Environmental and Symbiotic Sciences, Kumamoto Prefectural University, 3-1-100 Tsukide, Kumamoto 862-8502 (Japan); Abe, Shin-Ichi [Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555 (Japan); Kitano, Takeshi [Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555 (Japan); Shimada, Hideaki [Faculty of Education, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555 (Japan); Watanabe, Izumi [Faculty of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchuu-city, Tokyo 183-8509 (Japan); Li Weihua [Shanghai Institute of Planned Parenthood Research, 2140 Xie Tu road, Shanghai 200032 (China); Ding Xucheng [Shanghai Institute of Planned Parenthood Research, 2140 Xie Tu road, Shanghai 200032 (China)

    2005-02-01

    Contamination by persistent organochlorines (OCs), such as DDTs, hexachlorocyclohexane isomers (HCHs), chlordane compounds (CHLs), hexachlorobenzene (HCB) and polychlorinated biphenyls (PCBs) were examined in sediments, soils, fishes, crustaceans, birds, and aquaculture feed from Lake Tai, Hangzhou Bay, and in the vicinity of Shanghai city in China during 2000 and 2001. OCs were detected in all samples analyzed, and DDT and its metabolites were the predominant contaminants in most sediments, soils and biota. Concentrations of p,p'-DDT and ratio of p,p'-DDT to {sigma}DDTs were significantly higher in marine fishes than those in freshwater fishes. While the use of DDTs has been officially banned in China since 1983, these results indicate a recent input of technical DDTs into the marine environment around Hangzhou Bay. Comparison of organochlorine concentrations in fishes collected from Lake Tai and Hangzhou Bay suggests the presence of local sources of HCHs, chlordanes and PCBs at Lake Tai. Higher proportions of penta- and hexa-PCB congeners in fishes at Lake Tai may suggest the use of highly chlorinated PCB product, such as PCB{sub 5}, around this lake. To our knowledge, this is a first comprehensive study to examine the present status of organochlorine contamination in various environmental media, such as sediments, soils and wildlife, in China. - Elevated concentrations of DDTs were detected in sediments, soils, and wildlife collected from China.

  11. An Investigation of the Influence of Waves on Sediment Processes in Skagit Bay

    Science.gov (United States)

    2012-09-30

    coupled wave- current model will resolve the influence of external processes, including tidal forcing, buoyant river discharge, fluvial sediment...panel: energy vs. depth. Fetch calculation includes water level, direction, and position of the observation (Fig 2). 2. Erosion Potential...to set the boundary condition for the momentum equations. Maximum stresses are used to compute the potential cumulative erosion (PCE) in meters. For

  12. Shift in detrital sedimentation in the eastern Bay of Bengal during the late Quaternary

    Digital Repository Service at National Institute of Oceanography (India)

    PrakashBabu, C.; Pattan, J.N.; Dutta, K.; Basavaiah, N.; Prasad, G.V.K.; Ray, D.K.; Govil, P.

    the late Quaternary period. Units 2 (43-24 cm) and 1 (24-0 cm) represent enhanced and reduced supply of coarse-grained detrital sediments from the Ganges River during early and late Holocene period, respectively. Increased terrigenous supply dilutes calcium...

  13. Assessing diversity and phytoremediation potential of mangroves for copper contaminated sediments in Subic Bay, Philippines

    Science.gov (United States)

    Toxic metal pollution of water and soil is a major environmental problem and most conventional remediation approaches may not provide adequate solutions. An alternative way of reducing copper (Cu) concentration from contaminated sediments is through phytoremediation. Presently, there are few researc...

  14. Time series current meter and other data from moorings in the North Atlantic in support of the Current and Sediment Transport in Buzzards Bay Field program from 05 July 1982 to 05 December 1985 (NODC Accession 0056730)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A field experiment designed to determine the near-bottom circulation in Buzzards Bay and the transport of fine-grained sediments. The transport of fine-grained...

  15. Recording of the Holocene sediment infilling in a confined tide-dominated estuary: the bay of Brest (Britanny, France)

    Science.gov (United States)

    Gregoire, Gwendoline; Le Roy, Pascal; Ehrhold, Axel; Jouet, Gwenael; Garlan, Thierry

    2016-04-01

    Modern estuaries constitute key areas for the preservation of sedimentary deposits related to the Holocene period. Several previous studies using stratigraphic reconstructions in such environments allowed to characterise the major parameters controlling the Holocene transgressive sequence and to decipher their respective role in the sedimentary infill: (1) the evolution of main hydrologic factors (wave or tide-dominated environment), (2) the sea level fluctuation and (3) the morphologies of the bedrock and the coastline. Nevertheless, the timing of the transgressive deposits and the detailed facies need to be precise in regard to the stratigraphic schemes. The Bay of Brest (Western Brittany, France) offers the opportunity to examine these points and to compare with previous studies. It constitutes an original tide-dominated estuary that communicates to the open sea (Iroise Sea) by a narrow strait. Two main rivers (Aulne and Elorn) are connected to a submerged paleovalleys network that was incised in the Paleozoic basement during lowstands and still preserved in the present morphology. It delineates the central basin surrounded by tidal flat located in sheltered area. The analysis of high and very-high resolution seismic lines recorded through the whole bay combined with sediment cores (up to 4.5 m long) and radiocarbon dating allow to precise the architecture and the timing of the thick Holocene coastal wedge. It is preserved from the valley network to the shore and presents a longitudinal variability (downstream-upstream evolution). The infill is divided into two successive stages (corresponding to the transgressive and highstand system tracts) which laterally evolve from the paleo-valley to the coast. Two units constitute the transgressive system tract. The oldest, dated from 8200 to 7000 cal B.P. is composed of fine-grained, organic-rich tidal flat deposits located in the sheltered area and organised in levees on the terrace bordering the paleo-valley. A tidal

  16. Geospatial approach towards enumerative analysis of suspended sediment concentration for Ganges-Brahmaputra Bay

    Science.gov (United States)

    Pandey, Palak; Kunte, Pravin D.

    2016-10-01

    This study presents an easy, modular, user-friendly, and flexible software package for processing of Landsat 7 ETM and Landsat 8 OLI-TIRS data for estimating suspended particulate matter concentrations in the coastal waters. This package includes 1) algorithm developed using freely downloadable SCILAB package, 2) ERDAS Models for iterative processing of Landsat images and 3) ArcMAP tool for plotting and map making. Utilizing SCILAB package, a module is written for geometric corrections, radiometric corrections and obtaining normalized water-leaving reflectance by incorporating Landsat 8 OLI-TIRS and Landsat 7 ETM+ data. Using ERDAS models, a sequence of modules are developed for iterative processing of Landsat images and estimating suspended particulate matter concentrations. Processed images are used for preparing suspended sediment concentration maps. The applicability of this software package is demonstrated by estimating and plotting seasonal suspended sediment concentration maps off the Bengal delta. The software is flexible enough to accommodate other remotely sensed data like Ocean Color monitor (OCM) data, Indian Remote Sensing data (IRS), MODIS data etc. by replacing a few parameters in the algorithm, for estimating suspended sediment concentration in coastal waters.

  17. Distribution of Heavy Metals in Surface Sediments of the Bay of Bengal Coast

    Directory of Open Access Journals (Sweden)

    M. Z. H. Khan

    2017-01-01

    Full Text Available The concentrations of major (Si, Al, Ca, Fe, and K and minor (Cd, Mn, Ni, Pb, U, Zn, Co, Cr, As, Cu, Rb, Sr, and Zr, elements in the surficial sediments were studied in an attempt to establish their concentration in the Bengal coast. It was revealed that the majority of the trace elements have been introduced into the Bengal marine from the riverine inflows that are also affected by the impact of industrial, ship breaking yard, gas production plant, and urban wastes. The concentration of heavy metals was measured using Atomic Absorption Spectroscopy and Energy Dispersive X-ray fluorescence instruments. The highest concentrations for several trace elements were thus recorded which generally decrease with distance from the coast. It was observed that the heavy metal concentrations in the sediments generally met the criteria of international marine sediment quality. However, both the contamination factor and pollution load index values suggested the elevation of some metals’ concentrations in the region. Constant monitoring of the Bengal coast water quality needs to be recorded with a view to minimizing the risk of health of the population and the detrimental impacts on the aquatic ecosystem.

  18. Distribution of Heavy Metals in Surface Sediments of the Bay of Bengal Coast

    Science.gov (United States)

    Hasan, M. R.; Khan, M.; Aktar, S.; Fatema, K.

    2017-01-01

    The concentrations of major (Si, Al, Ca, Fe, and K) and minor (Cd, Mn, Ni, Pb, U, Zn, Co, Cr, As, Cu, Rb, Sr, and Zr,) elements in the surficial sediments were studied in an attempt to establish their concentration in the Bengal coast. It was revealed that the majority of the trace elements have been introduced into the Bengal marine from the riverine inflows that are also affected by the impact of industrial, ship breaking yard, gas production plant, and urban wastes. The concentration of heavy metals was measured using Atomic Absorption Spectroscopy and Energy Dispersive X-ray fluorescence instruments. The highest concentrations for several trace elements were thus recorded which generally decrease with distance from the coast. It was observed that the heavy metal concentrations in the sediments generally met the criteria of international marine sediment quality. However, both the contamination factor and pollution load index values suggested the elevation of some metals' concentrations in the region. Constant monitoring of the Bengal coast water quality needs to be recorded with a view to minimizing the risk of health of the population and the detrimental impacts on the aquatic ecosystem. PMID:28255298

  19. Response of Microbial Community to Petroleum Stress and Phosphate Dosage in Sediments of Jiaozhou Bay, China

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yangguo; CHEN Min; BAI Jie; LI Xinwei; Farhana Zulfiqar; WANG Qianli

    2014-01-01

    The dynamic microcosms were used to evaluate the effect of oil spills on microbial ecological system in marine sedi-ment and the enhancement of nutrient on the oil removal. The function and structure of microbial community caused by the oil pollu-tion and phosphate dosage were simultaneously monitored by dehydrogenase activity assay and PCR-denaturing gradient gel elec-trophoresis (DGGE) techniques. The results indicated that the amount of total bacteria in all dynamic microcosms declined rapidly with incubation time. The number of petroleum-degrading bacteria and the activity of sediment dehydrogenase were gradually en-hanced by petroleum in the oil-treated microcosms, while they both showed no obvious response to phosphate dosage. In comparison, phosphate spiked heterotrophic bacteria and they showed a significant increase in amount. DGGE profiles indicated that petroleum dosage greatly changed community structure, and the bacteria belonged to class Deltaproteobacteria, and phyla Bacteroidetes and Chlorobi were enriched. This study demonstrated that petroleum input greatly impacted the microbial community structure and con-sequently the marine sediment petroleum-degrading activity was enhanced. Phosphate dosage would multiply heterotrophic bacteria but not significantly enhance the petroleum degradation.

  20. Distribution of Heavy Metals in Surface Sediments of the Bay of Bengal Coast.

    Science.gov (United States)

    Khan, M Z H; Hasan, M R; Khan, M; Aktar, S; Fatema, K

    2017-01-01

    The concentrations of major (Si, Al, Ca, Fe, and K) and minor (Cd, Mn, Ni, Pb, U, Zn, Co, Cr, As, Cu, Rb, Sr, and Zr,) elements in the surficial sediments were studied in an attempt to establish their concentration in the Bengal coast. It was revealed that the majority of the trace elements have been introduced into the Bengal marine from the riverine inflows that are also affected by the impact of industrial, ship breaking yard, gas production plant, and urban wastes. The concentration of heavy metals was measured using Atomic Absorption Spectroscopy and Energy Dispersive X-ray fluorescence instruments. The highest concentrations for several trace elements were thus recorded which generally decrease with distance from the coast. It was observed that the heavy metal concentrations in the sediments generally met the criteria of international marine sediment quality. However, both the contamination factor and pollution load index values suggested the elevation of some metals' concentrations in the region. Constant monitoring of the Bengal coast water quality needs to be recorded with a view to minimizing the risk of health of the population and the detrimental impacts on the aquatic ecosystem.

  1. Chronology of anthropogenic impacts reconstructed from sediment records of trace metals and Pb isotopes in Todos os Santos Bay (NE Brazil).

    Science.gov (United States)

    Andrade, R L B; Hatje, V; Masqué, P; Zurbrick, C M; Boyle, E A; Santos, W P C

    2017-08-08

    The evolution of the impacts of anthropogenic activities in Todos os Santos Bay was evaluated by profiles of trace metals and Pb isotopes determined in sediment cores. Fluxes of metals increased up to 12, 4 and 2 times for Cu, Pb, and Zn, respectively, compared to those recorded in the beginning of the 20(th) century. Stable Pb isotopes identified a decommissioned lead smelter and burning of fossil fuels as the main sources of Pb. Most metals showed minor to moderate enrichment factors (EF<4), but Cu and Pb were highly enriched (EF=28 and 6, respectively) at the Aratu harbor. Temporal changes in sediments were associated to different activities, namely Pb smelting, burning of fossil fuels, maritime traffic, petroleum related activities, inputs of domestic effluents, and changes in land uses. The effects of the implementation of environmental policies to improve the waters of the bay could not be identified in the evaluated cores. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Accumulation patterns of lipophilic organic contaminants in surface sediments and in economic important mussel and fish species from Jakarta Bay, Indonesia.

    Science.gov (United States)

    Dwiyitno; Dsikowitzky, Larissa; Nordhaus, Inga; Andarwulan, Nuri; Irianto, Hari Eko; Lioe, Hanifah Nuryani; Ariyani, Farida; Kleinertz, Sonja; Schwarzbauer, Jan

    2016-09-30

    Non-target screening analyses were conducted in order to identify a wide range of organic contaminants in sediment and animal tissue samples from Jakarta Bay. High concentrations of di-iso-propylnaphthalenes (DIPNs), linear alkylbenzenes (LABs) and polycyclic aromatic hydrocarbons (PAHs) were detected in all samples, whereas phenylmethoxynaphthalene (PMN), DDT and DDT metabolites (DDX) were detected at lower concentrations. In order to evaluate the uptake and accumulation by economic important mussel (Perna viridis) and fish species, contaminant patterns of DIPNs, LABs and PAHs in different compartments were compared. Different patterns of these contaminant groups were found in sediment and animal tissue samples, suggesting compound-specific accumulation and metabolism processes. Significantly higher concentrations of these three contaminant groups in mussel tissue as compared to fish tissue from Jakarta Bay were found. Because P. viridis is an important aquaculture species in Asia, this result is relevant for food safety.

  3. Spatial distribution and concentration assessment of total petroleum hydrocarbons in the intertidal zone surface sediment of Todos os Santos Bay, Brazil.

    Science.gov (United States)

    Silva, Carine S; Moreira, Icaro T A; de Oliveira, Olivia M C; Queiroz, Antonio F S; Garcia, Karina S; Falcão, Brunno A; Escobar, Narayana F C; Rios, Mariana Cruz

    2014-02-01

    The primary objective of this study was to investigate the concentrations and spatial distribution of the total petroleum hydrocarbons (TPHs) in the intertidal zone surface sediment of Todos os Santos Bay, Brazil, to assess the distribution and degree of contamination by TPHs, measure the level of TPH degradation in the surface sediment, and identify the organic matter sources. The surface sediment used in this study was collected in 50 stations, and TPHs, isoprenoid alkanes (pristane and phytane), and unresolved complex mixture (UCM) were analyzed by gas chromatography with a flame ionization detector. The total concentrations ranged from 0.22 to 40,101 μg g(-1) dry weight and showed a strong correlation with the total organic carbon (TOC) content. The highest TPH concentrations were observed in samples from the mangrove sediments of a river located near a petroleum refinery. Compared with other studies in the world, the TPH concentrations in the intertidal surface sediment of Todos os Santos Bay were below average in certain stations and above average in others. An analysis of the magnitude of UCM (0.11 to 17,323 μg g(-1) dry weight) and the ratios nC17/Pr and nC18/Ph suggest that an advanced state of oil weathering, which indicates previous contamination. The molar C/N ratios varied between 5 and 43, which indicate organic matter with a mixed origin comprising marine and continental contributions.

  4. 杭州湾湾口水体含沙量的时空分布%Spaciai-temporai distribution of suspended sediment concentration in Hangzhou Bay

    Institute of Scientific and Technical Information of China (English)

    吴明阳; 许家帅; 冯玉林

    2011-01-01

    利用卫星遥感资料,结合现场实测数据,研究杭州湾湾口水体含沙量的时空分布,综合分析得出:杭州湾水体含沙量具有冬大夏小、高浓度悬沙广泛分布的特性,岛屿效应引起的局部高含沙是杭州湾岛屿群的共性.%Based on the information from the satelite remote sensing image and the measured SSC data from the field stations, this paper studies the spacial-temporal distribution of the sediment concentration in the Hangzhou Bay. The SSC of the Hangzhou Bay is high in winter and low in summer and the high SSC distributes extensively in the bay. It is common in the Hangzhou Bay that the locally high sediment concentration is caused by the archipelago effect.

  5. Gas exchange rates across the sediment-water and air-water interfaces in south San Francisco Bay

    Science.gov (United States)

    Hartman, Blayne; Hammond, Douglas E.

    1984-01-01

    Radon 222 concentrations in the water and sedimentary columns and radon exchange rates across the sediment-water and air-water interfaces have been measured in a section of south San Francisco Bay. Two independent methods have been used to determine sediment-water exchange rates, and the annual averages of these methods agree within the uncertainty of the determinations, about 20%. The annual average of benthic fluxes from shoal areas is nearly a factor of 2 greater than fluxes from the channel areas. Fluxes from the shoal and channel areas exceed those expected from simple molecular diffusion by factors of 4 and 2, respectively, apparently due to macrofaunal irrigation. Values of the gas transfer coefficient for radon exchange across the air-water interface were determined by constructing a radon mass balance for the water column and by direct measurement using floating chambers. The chamber method appears to yield results which are too high. Transfer coefficients computed using the mass balance method range from 0.4 m/day to 1.8 m/day, with a 6-year average of 1.0 m/day. Gas exchange is linearly dependent upon wind speed over a wind speed range of 3.2–6.4 m/s, but shows no dependence upon current velocity. Gas transfer coefficients predicted from an empirical relationship between gas exchange rates and wind speed observed in lakes and the oceans are within 30% of the coefficients determined from the radon mass balance and are considerably more accurate than coefficients predicted from theoretical gas exchange models.

  6. Geospatial approach towards enumerative analysis of suspended sediment concentration for Ganges-Brahmaputra Bay

    Digital Repository Service at National Institute of Oceanography (India)

    Pandey, P.; Kunte, P.D.

    stream_size 47513 stream_content_type text/plain stream_name Comput_Geosci_95_32a.pdf.txt stream_source_info Comput_Geosci_95_32a.pdf.txt Content-Encoding UTF-8 Content-Type text/plain; charset=UTF-8 1    Author Version...-dominated coastal waters, sophisticated algorithms are mainly needed to estimate accurately the suspended particulate concentrations from remotely sensed ocean color data (Robinson et al., 1998; Moore et al., 1999). Suspended sediment transport is a continuous...

  7. Photobacterium marinum sp. nov., a marine bacterium isolated from a sediment sample from Palk Bay, India

    Digital Repository Service at National Institute of Oceanography (India)

    Srinivas, T.N.R.; VijayaBhaskar, Y.; Bhumika, V.; AnilKumar, P.

    and fermentative type of metabolism, non spore forming, facultative anaerobes. The DNA G + C content range for the genus Photobacterium is between 39-50.6 mol%. Genus Photobacterium belongs to the family Vibrionaceae. Some members of the genus are bioluminescent... the samples, temperature was 31oC and salinity was 32.62 ppt. Approximately 100 mg of the sediment sample was suspended in 900 ml of sterile saline water (3% NaCl w/v) and subjected to shaking for 2 h. The supernatant was serially diluted and 100 µl...

  8. Manganese, Iron, and Sulfur Cycling in a Coastal Marine Sediment, Aarhus Bay, Denmark

    DEFF Research Database (Denmark)

    THAMDRUP, B.; FOSSING, H.; JØRGENSEN, BB

    1994-01-01

    -scale measurements showed that it extended to the upper 0-2.5 mm during summer, when the zones of Mn and Fe reduction were compressed towards the surface. Most of the H2S produced precipitated as iron sulfides and S0 by reaction with Fe. Both Fe(III) and a nonsulfur-bound authigenic Fe(II) pool reacted efficiently...... with H2S. The authigenic Fe(II) pool was present at one hundredfold higher concentration than dissolved Fe2+. Only 15% of the precipitated sulfide was buried permanently. Most of the reoxidation of reduced S occurred within 1 cm of the sediment-water interface and was supported by upward bioturbation......The seasonal variation in oxidized and reduced pools of Mn, Fe, and S, as well as the rates of SO4(2-) reduction, were studied in a fine-grained sediment. Below the 1-5 mm thick oxic zone, a zone of net Mn reduction extended to 1-2 cm depth, while iron reduction was found to 4-6 cm depth. Although...

  9. Stepped Holocene sea-level rise and its influence on sedimentation in a large marine embayment: Maputo Bay, Mozambique

    Science.gov (United States)

    De Lecea, A. M.; Green, A. N.; Strachan, K. L.; Cooper, J. A. G.; Wiles, E. A.

    2017-07-01

    The sedimentary record in large marine embayments holds important information on Holocene environmental and sea-level changes. This paper investigates the evolution of a large subtropical marine embayment, Maputo Bay, in southern Mozambique. Using a combination of sediment cores, stable isotope data, seismic reflection profiling and 14C dating, we show complex back-barrier changes during the Holocene and link these to stepped rises in sea level. Our data reveal a sea-level ;slowstand; followed by an abrupt rise that we correlate with the 8.2 ka global rise in sea level. Sedimentological, isotope and seismic evidence point to a subsequent slowstand interspersed by two punctuated rises in sea level that formed clear tidal ravinement surfaces. Sedimentary changes in the embayment are primarily forced by sea-level change, whereby tidal ravinement surfaces sandwich normal regressive packages formed via marginal progradation and shallowing of the system during ;slow-; or still-stands. Large marine embayment systems hold great potential in unravelling relative sea-level change. Axiomatically, this reduces their utility as archives of climate-change.

  10. Evaluation of sediment trace metal records as paleoproductivity and paleoxygenation proxies in the upwelling center off Concepción, Chile (36°S)

    Science.gov (United States)

    Muñoz, Praxedes; Dezileau, Laurent; Lange, Carina; Cardenas, Lissette; Sellanes, Javier; Salamanca, Marco A.; Maldonado, Antonio

    2012-01-01

    This study analyzes the records of several trace metals sensitive to redox conditions in continental shelf sediments off Concepción, Chile (36°S). The continental margin off Concepción (36°S; 73°W) lies beneath an important upwelling center characterized by high primary production rates and, consequently, high fluxes of organic matter. In spring and summer, this material settles to the seafloor where it decays, producing periods of very low oxygen content in bottom waters (oxygen minimum zone develops at ∼100-400 m water depth, where dissolved oxygen levels are events, when dissolved oxygen at the bottom increases drastically (>1 mL L -1). The goals of this study were to determine the input of trace metals to the sediment and to decipher how this information can be used to reveal variations in primary productivity or bottom oxygenation. Gravity cores collected at two stations - VG06-2 over the mid-shelf station (88 m water depth, upper boundary of the oxygen minimum zone) and VG06-3 over the outer shelf (120 m water depth, within the oxygen minimum zone) - were sampled for high resolution profiles (1 cm) of trace metals, biogenic opal, stable isotopes, and total organic carbon. The results suggest that the variability in the trace metal distribution on the continental shelf off Concepción is determined by redox conditions and the organic carbon flux to the bottom. Some sections of the sediment cores from the outer shelf showed appreciable authigenic enrichment of U, Cd, and Mo (EF: 5-10, 2-5, and 10-16 respectively) along with heavier values of δ 15N, suggesting periods of suboxic conditions. During these periods, fluxes of organic material to the bottom were higher, as indicated by elevated TOC and opal contents. Alternating periods of higher and lower trace metal contents were not observed mid-shelf as they were on the outer shelf. Rather, the mid-shelf samples showed authigenic enrichment of U, Cd, and Mo (EF: 1-6, 4-5, and 10-20, respectively

  11. Sedimentological characteristics and depositional processes of sediment gravity flows in rift basins: The Palaeogene Dongying and Shahejie formations, Bohai Bay Basin, China

    Science.gov (United States)

    Liu, Lei; Chen, Hongde; Zhong, Yijiang; Wang, Jun; Xu, Changgui; Chen, Anqing; Du, Xiaofeng

    2017-10-01

    Sediment gravity flow deposits are common, particularly in sandy formations, but their origin has been a matter of debate and there is no consensus about the classification of such deposits. However, sediment gravity flow sandstones are economically important and have the potential to meet a growing demand in oil and gas exploration, so there is a drive to better understand them. This study focuses on sediment gravity flow deposits identified from well cores in Palaeogene deposits from the Liaodong Bay Depression in Bohai Bay Basin, China. We classify the sediment gravity flow deposits into eight lithofacies using lithological characteristics, grain size, and sedimentary structures, and interpret the associated depositional processes. Based on the scale, spatial distribution, and contact relationships of sediment gravity flow deposits, we defined six types of lithofacies associations (LAs) that reflect transformation processes and depositional morphology: LA1 (unconfined proximal breccia deposits), LA2 (confined channel deposits), LA3 (braided-channel lobe deposits), LA4 (unconfined lobe deposits), LA5 (distal sheet deposits), and LA6 (non-channelized sheet deposits). Finally, we established three depositional models that reflect the sedimentological characteristics and depositional processes of sediment gravity flow deposits: (1) slope-apron gravel-rich depositional model, which involves cohesive debris flows deposited as LA1 and dilute turbidity currents deposited as LA5; (2) non-channelized surge-like turbidity current depositional model, which mainly comprises sandy slumping, suspended load dominated turbidity currents, and dilute turbidity currents deposited as LA5 and LA6; and (3) channelized subaqueous-fan depositional model, which consists of non-cohesive bedload dominated turbidity currents, suspended load dominated turbidity currents, and dilute turbidity currents deposited as LA2-LA5, originating from sustained extrabasinal turbidity currents

  12. Distribution of chemical elements in calc-alkaline igneous rocks, soils, sediments and tailings deposits in northern central Chile

    Science.gov (United States)

    Oyarzún, Jorge; Oyarzun, Roberto; Lillo, Javier; Higueras, Pablo; Maturana, Hugo; Oyarzún, Ricardo

    2016-08-01

    This study follows the paths of 32 chemical elements in the arid to semi-arid realm of the western Andes, between 27° and 33° S, a region hosting important ore deposits and mining operations. The study encompasses igneous rocks, soils, river and stream sediments, and tailings deposits. The chemical elements have been grouped according to the Goldschmidt classification, and their concentrations in each compartment are confronted with their expected contents for different rock types based on geochemical affinities and the geologic and metallogenic setting. Also, the element behavior during rock weathering and fluvial transport is here interpreted in terms of the ionic potentials and solubility products. The results highlight the similarity between the chemical composition of the andesites and that of the average Continental Crust, except for the higher V and Mn contents of the former, and their depletion in Mg, Ni, and Cr. The geochemical behavior of the elements in the different compartments (rocks, soils, sediments and tailings) is highly consistent with the mobility expected from their ionic potentials, their sulfates and carbonates solubility products, and their affinities for Fe and Mn hydroxides. From an environmental perspective, the low solubility of Cu, Zn, and Pb due to climatic, chemical, and mineralogical factors reduces the pollution risks related to their high to extremely high contents in source materials (e.g., rocks, altered zones, tailings). Besides, the complex oxyanions of arsenic get bound by colloidal particles of Fe-hydroxides and oxyhydroxides (e.g., goethite), thus becoming incorporated to the fine sediment fraction in the stream sediments.

  13. Dynamics of REE accumulation and fractionation in the subcolloidal fraction of bottom sediments in the Razdol'naya River-Amur Bay section, Sea of Japan

    Science.gov (United States)

    Polyakov, D. M.

    2016-05-01

    The REE contents (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) are determined by atomic emission spectroscopy in the subcolloidal fraction of bottom sediments in the Razdol'naya River-Amur Bay section. The mean contents of lanthanides in soils and river bottom sediments (before the mixing zone) are calculated. The increase in REE content and the fractioning in the series from light to middle and heavy REE in sediments of different estuary zones (river, water mixing, and marine), with the latter related to flocculation, sorption on iron and manganese hydroxides, clay minerals (hydromica, smectites), and lifetime accumulation of marine plankton, are dtermined. Via extraction of 0.5 N sodium hydroxide solution, the content of lanthanides associated with humic substances of subcolloidal fraction from the Amur Bay sediments are determined: 1.3 to 8.2% of La; 1.1 to 11% of Ce; and 0.3 to 1.5 of Gd.

  14. Bacterial Enzymatic Activity and Bioavailability of Heavy Metals in Sediments from Boa Viagem Beach (Guanabara Bay

    Directory of Open Access Journals (Sweden)

    Mirian Crapez

    2003-01-01

    Full Text Available This study focuses on the quality of the organic matter that reaches the sediment from Boa Viagem Beach and through the evaluation of the total bacterial count, the electron transport system activity (ETSA, the esterase activity (EST, as well as the protein and the organic matter contents. Seasonal variations of organic matter, protein content and the number of bacteria were particularly notable in the summer. ETSA reached a maximum of 7.48 µl O 2 h-1 g-1 in the summer. EST activity presented a different pattern once it reached a maximum of 0.17 µg fluorescein h-1 g-1 in the winter. The temporal variation of ETSA and EST activity indicated that biopolymers predominated in the winter, and oligomers or monomers predominated in the summer. These results suggest that organic carbon turnover is more likely to be controlled by organic matter quality. The heavy metals concentrations, especially for Cu, Zn, Ni and Cr, indicated absence of the inhibition of dehydrogenase activity, and they are not bioavailable in the EC 50 values

  15. Sediment profile image data from June 1995 in Lower Bay of New York/New Jersey Harbor

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Sediment profile images (SPI) of the sediment-water interface were collected using a sediment profiling camera at pre-determined locations in the harbor. Physical,...

  16. Sediment profile image data from June 1995 in the inland bays of New York/New Jersey Harbor

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Sediment profile images (SPI) of the sediment-water interface were collected using a sediment profiling camera at pre-determined locations in the harbor. Physical,...

  17. Sediment profile image data from October 1994 in Lower Bay of New York/New Jersey Harbor

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Sediment profile images (SPI) of the sediment-water interface were collected using a sediment profiling camera at pre-determined locations in the harbor. Physical,...

  18. Sediment profile image data from October 1995 in the inland bays of New York/New Jersey Harbor

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Sediment profile images (SPI) of the sediment-water interface were collected using a sediment profiling camera at pre-determined locations in the harbor. Physical,...

  19. Multivariate Analyses and Evaluation of Heavy Metals by Chemometric BCR Sequential Extraction Method in Surface Sediments from Lingdingyang Bay, South China

    Directory of Open Access Journals (Sweden)

    Linglong Cao

    2015-04-01

    Full Text Available Sediments in estuary areas are recognized as the ultimate reservoirs for numerous contaminants, e.g., toxic metals. Multivariate analyses by chemometric evaluation were performed to classify metal ions (Cu, Zn, As, Cr, Pb, Ni and Cd in superficial sediments from Lingdingyang Bay and to determine whether or not there were potential contamination risks based on the BCR sequential extraction scheme. The results revealed that Cd was mainly in acid-soluble form with an average of 75.99% of its total contents and thus of high potential availability, indicating significant anthropogenic sources, while Cr, As, Ni were enriched in the residual fraction which could be considered as the safest ingredients to the environment. According to the proportion of secondary to primary phases (KRSP, Cd had the highest bioavailable fraction and represented high or very high risk, followed by Pb and Cu with medium risks in most of samples. The combined evaluation of the Pollution Load Index (PLI and the mean Effect Range Median Quotient (mERM-Q highlighted that the greatest potential environmental risk area was in the northwest of Lingdingyang Bay. Almost all of the sediments had a 21% probability of toxicity. Additionally, Principal Component Analysis (PCA revealed that the survey region was significantly affected by two main sources of anthropogenic contributions: PC1 showed increased loadings of variables in acid-soluble and reducible fractions that were consistent with the input from industrial wastes (such as manufacturing, metallurgy, chemical industry and domestic sewages; PC2 was characterized by increased loadings of variables in residual fraction that could be attributed to leaching and weathering of parent rocks. The results obtained demonstrated the need for appropriate remediation measures to alleviate soil pollution problem due to the more aggregation of potentially risky metals. Therefore, it is of crucial significance to implement the targeted

  20. Examination of factors dominating the sediment-water diffusion flux of DDT-related compounds measured by passive sampling in an urbanized estuarine bay.

    Science.gov (United States)

    Feng, Yan; Wu, Chen-Chou; Bao, Lian-Jun; Shi, Lei; Song, Lin; Zeng, Eddy Y

    2016-12-01

    The fate of hydrophobic organic compounds in aquatic environment are largely determined by their exchange at sediment-water interface, which is highly dynamic and subject to rapidly evolving environmental conditions. In turn, environmental conditions may be governed by both physicochemical parameters and anthropogenic events. To examine the importance of various impact factors, passive sampling devices were deployed at the seafloor of Hailing Bay, an urbanized estuarine bay in Guangdong Province of South China to measure the sediment-water diffusion fluxes of several metabolites of dichlorodiphenyltrichloroethane (DDT), p,p'-DDE, p,p'-DDD and o,p'-DDD. The physicochemical properties of water (temperature, pH, salinity and dissolved oxygen) and surface sediment (sediment organic matter, physical composition, pH, water content, colony forming unit and catalase activity) were also measured. The results showed that the diffusion fluxes of o,p'-DDD, p,p'-DDD and p,p'-DDE at sites A1 and A2 near a fishing boat maintenance facility ranged from 0.42 to 4.73 ng m(-2) d(-1) (from sediment to overlying water), whereas those at offshore sites varied between -0.03 and -3.02 ng m(-2) d(-1) (from overlying water to sediment), implicating A1 and A2 as the sources of the target compounds. The distribution patterns of the diffusion fluxes of the target compounds were different from those of water and sediment parameters (water temperature, salinity, sediment texture, pH, colony forming unit and catalase activity) at six sampling sites. This finding suggested that none of these parameters were critical in dictating the sediment-water diffusion fluxes. Besides, decreases in the contents of kerogen and black carbon by 6.7% and 11% would enhance the diffusion fluxes of the target compounds by 11-14% and 12-23%, respectively, at site A1, indicating that kerogen and black carbon were the key factors in mediating the sediment-water diffusion fluxes of DDT-related compounds in field

  1. Abundance, composition and vertical distribution of polycyclic aromatic hydrocarbons in sediments of the Mai Po Inner Deep Bay of Hong Kong.

    Science.gov (United States)

    Zhao, Zhenye; Zhuang, Yi-Xuan; Gu, Ji-Dong

    2012-08-01

    The distribution and changes of polycyclic aromatic hydrocarbons (PAHs) contamination in mangrove sediments of Mai Po Inner Deep Bay Ramsar Site of Hong Kong SAR were investigated. Surface sediments (10 cm) collected from four sampling sites (SZ, SP, MF and M) exhibited significant spatial variations in concentrations of total PAH (with ΣPAHs ranging from 161.7 to 383.7 ng g(-1) dry wt), as well as the composition of 16 US EPA priority PAH compounds. The highest PAHs concentrations were found in the mangrove sediments. Moreover, a sediment core was extracted from mangrove area is used to reconstruct the high-resolution depositional record of PAHs by (210)Pb isotope analysis, showing the amounts of PAHs remained relatively constant for the past 41 years. Urbanization of Shenzhen Economic Zone, the rapid increase in vehicle numbers and energy consumption in the last two decades contributed to the PAHs detected in sediments. The source-diagnostic ratios indicated that pyrogenic input are important throughout the record and the surface sediments, and suggest that diesel fuel combustion, and hence traffic of heavier vehicles, is the most probable cause of PAHs.

  2. Coastal Circulation and Sediment Dynamics in Hanalei Bay, Kaua'i, Part IV, Measurements of Waves, Currents, Temperature, Salinity, and Turbidity, June-September 2006

    Science.gov (United States)

    Storlazzi, Curt D.; Presto, M. Katherine; Logan, Joshua B.; Field, Michael E.

    2008-01-01

    High-resolution measurements of waves, currents, water levels, temperature, salinity and turbidity were made in Hanalei Bay, northern Kaua'i, Hawai'i, during the summer of 2006 to better understand coastal circulation, sediment dynamics, and the potential impact of a river flood in a coral reef-lined embayment during quiescent summer conditions. A series of bottommounted instrument packages were deployed in water depths of 10 m or less to collect long-term, high-resolution measurements of waves, currents, water levels, temperature, salinity, and turbidity. These data were supplemented with a series of profiles through the water column to characterize the vertical and spatial variability in water column properties within the bay. These measurements support the ongoing process studies being conducted as part of the U.S. Geological Survey (USGS) Coastal and Marine Geology Program's Pacific Coral Reef Project; the ultimate goal is to better understand the transport mechanisms of sediment, larvae, pollutants, and other particles in coral reef settings. Information regarding the USGS study conducted in Hanalei Bay during the 2005 summer is available in Storlazzi and others (2006), Draut and others (2006) and Carr and others (2006). This report, the last part in a series, describes data acquisition, processing, and analysis for the 2006 summer data set.

  3. Oxygenation variability off Northern Chile during the last two centuries

    Directory of Open Access Journals (Sweden)

    J. A. Díaz-Ochoa

    2010-07-01

    Full Text Available The Peru Chile Current ecosystem is characterized by high biological productivity and important fisheries. Although this system is likely to be severely affected by climate change, its response to current global warming is still uncertain. In this paper we analyze 10–166 year old sediments in two cores collected in Mejillones Bay, an anoxic sedimentary setting favorable for preservation of proxies. Based on a 166 year chronology we used indicators of bottom water oxygenation proxies (Mo, V, S, and the (lycopane+n-C35/n-C31 ratio and surface water productivity (biogenic opal, counts of diatom valves, biogenic Ba, organic carbon and chlorins to reconstruct environmental variations in Mejillones Bay. We find that at decadal scales, and during the last two centuries, a shift in the coastal marine ecosystem off Northern Chile took place which was characterized by intense ENSO-like activity and large fluctuations in biological export productivity, in bottom water oxygenation, and increased eolic activity (inferred from Ti/Al and Zr/Al. On top of this short-term variability, a gradual increase of sulfidic conditions has occurred being even more intensified since the early 1960s.

  4. Variability of the internal tide on the southern Monterey Bay continental shelf and associated bottom boundary layer sediment transport

    Science.gov (United States)

    Rosenberger, Kurt J.; Storlazzi, Curt D.; Cheriton, Olivia M.

    2016-06-01

    A 6-month deployment of instrumentation from April to October 2012 in 90 m water depth near the outer edge of the mid-shelf mud belt in southern Monterey Bay, California, reveals the importance regional upwelling on water column density structure, potentially accounting for the majority of the variability in internal tidal energy flux across the shelf. Observations consisted of time-series measurements of water-column currents, temperature and salinity, and near-bed currents and suspended matter. The internal tide accounted for 15-25% of the water-column current variance and the barotropic tide accounted for up to 35%. The subtidal flow showed remarkably little shear and was dominated by the 7-14 day band, which is associated with relaxations in the dominant equatorward winds typical of coastal California in the spring and summer. Upwelling and relaxation events resulted in strong near-bed flows and accounted for almost half of the current stress on the seafloor (not accounting for wave orbital velocities), and may have driven along-shelf geostrophic flow during steady state conditions. Several elevated suspended particulate matter (SPM) events occurred within 3 m of the bed and were generally associated with higher, long-period surface waves. However, these peaks in SPM did not coincide with the predicted resuspension events from the modeled combined wave-current shear stress, indicating that the observed SPM at our site was most likely resuspended elsewhere and advected along-isobath. Sediment flux was almost equal in magnitude in the alongshore and cross-shore directions. Instances of wave-current shear stress that exceeded the threshold of resuspension for the silty-clays common at these water depths only occurred when near-bed orbital velocities due to long-period surface waves coincided with vigorous near-bed currents associated with the internal tide or upwelling/relaxation events. Thus upwelling/relaxation dynamics are primarily responsible for variability

  5. Variability of the internal tide on the southern Monterey Bay continental shelf and associated bottom boundary layer sediment transport

    Science.gov (United States)

    Rosenberger, Kurt; Storlazzi, Curt; Cheriton, Olivia

    2016-01-01

    A 6-month deployment of instrumentation from April to October 2012 in 90 m water depth near the outer edge of the mid-shelf mud belt in southern Monterey Bay, California, reveals the importance regional upwelling on water column density structure, potentially accounting for the majority of the variability in internal tidal energy flux across the shelf. Observations consisted of time-series measurements of water-column currents, temperature and salinity, and near-bed currents and suspended matter. The internal tide accounted for 15–25% of the water-column current variance and the barotropic tide accounted for up to 35%. The subtidal flow showed remarkably little shear and was dominated by the 7–14 day band, which is associated with relaxations in the dominant equatorward winds typical of coastal California in the spring and summer. Upwelling and relaxation events resulted in strong near-bed flows and accounted for almost half of the current stress on the seafloor (not accounting for wave orbital velocities), and may have driven along-shelf geostrophic flow during steady state conditions. Several elevated suspended particulate matter (SPM) events occurred within 3 m of the bed and were generally associated with higher, long-period surface waves. However, these peaks in SPM did not coincide with the predicted resuspension events from the modeled combined wave–current shear stress, indicating that the observed SPM at our site was most likely resuspended elsewhere and advected along-isobath. Sediment flux was almost equal in magnitude in the alongshore and cross-shore directions. Instances of wave–current shear stress that exceeded the threshold of resuspension for the silty-clays common at these water depths only occurred when near-bed orbital velocities due to long-period surface waves coincided with vigorous near-bed currents associated with the internal tide or upwelling/relaxation events. Thus upwelling/relaxation dynamics are primarily responsible for

  6. Estructura comunitaria de diatomeas presentes en los sedimentos superficiales de ocho lagos andinos de Chile central Diatoms community structure in superficial sediments of eight Andean lakes of central Chile

    Directory of Open Access Journals (Sweden)

    INGRID E ALVIAL

    2008-03-01

    Full Text Available En este trabajo se analizó la estructura comunitaria de diatomeas depositadas en los sedimentos superficiales de ocho lagos andinos chilenos ubicados entre los 32°49' y 38°48' S. Se encontró un total de 99 taxa de diatomeas, distribuidos en 48 géneros. Del total de taxa, 74 fueron identificados a nivel de especie siendo todos ellos cosmopolitas a excepción de Eunotia andinofrequens, Gomphonema punae, Pinnularia araucanensis y Pinnularia acidicola, entre otras, que están descritos solo para el Hemisferio Sur. Por otro lado, las muestras analizadas presentaron distinta composición florística de diatomeas. De esta manera, en los ensambles diatomológicos depositados en los sedimentos de las lagunas de altura Ocho, Huifa, Ensueño y Negra ubicadas sobre los 2.860 m del nivel del mar, abundaron especies bentónicas, típicas de aguas oligotróficas y acidas como Achnanthidium exiguum, Achnanthidium minutissimum, Encyonema minutum, Pinnularia acidicola y Planothidium lanceolatum. En los ensambles diatomológicos de los lagos Galletué, Icalma y Laja, ubicados bajo los 1.360 m del nivel del mar, abundaron diatomeas planctónicas, características de aguas alcalinas y mesotróficas como Asterionella formosa, Aulacoseira distans, Aulacoseira granulata, Cyclotella stelligera y Rhopalodia gibbaIn this research the taxonomic structure of diatoms in sediments of high mountain lakes was studied. These lakes are located in Chile between 32°49' and 38°48' S in the Andean Cordillera. A total of 99 diatom taxa distributed in 48 genera were identified and all this taxa are cosmopolitan excepting a Eunotia andinofrequens, Gomphonema punae, Pinnularia araucanensis and Pinnularia acidicola, which are know only for the Southern Hemisphere. The assemblages of diatoms were different in the studied lakes. So the high mountain lakes Ocho, Huifa, Ensueño and Negra, dominated benthic diatoms which are typical of oligotrophic and acid waters as Achnanthidium

  7. Evaluation of surface water and sediment quality in Chicalim Bay, Nerul Creek, and Chapora Bay from Goa coast, India - a statistical approach

    Digital Repository Service at National Institute of Oceanography (India)

    Shenai-Tirodkar, P.S.; Gauns, M.U.; Ansari, Z.A.

    ores transportations. Nerul Creek (NC) (15°30’37.70” N, 73°46’48.75”E) opens into the Aguada Bay of Mandovi estuary and extends inside the land in U-shape up to a length of about ~8.5 km. This site is influenced by restaurants discharge, fishing...

  8. Water, organic matter, nitrogen and phosphorus contents in sediment of a large-scale mariculture area in the Zhelin Bay of eastern Guangdong Province, China

    Institute of Scientific and Technical Information of China (English)

    DONG Qiaoxiang; LIN Junda; SHANG Xu; LI Jin; HUANG Changjiang

    2008-01-01

    The Zhelin Bay is one of the most important bays for large-scale maricuhure in Guangdong Province,China.Owing to the increas-ing human population and the expanding marieuhure in the last two decades,the ecological environment has greatly changed with frequent harmful algal blooms.A monthly survey of water content,organic matter ( TOM ),and various forms of nitrogen and phosphorous in sediment from July 2002 to July 2003 in the bay was conducted.The results showed that the water content was cor-related significantly with TOM and various forms of nitrogen and phosphorus and can be used as proxy for quick and rough estimate of these factors in the future surveys.TOM was also correlated significantly with various forms of nitrogen and phosphorus,indica-ting that it was one of the key factors affecting the concentrations and distributions of nitrogen and phosphorus in the investigated waters. Average total Kjeldhal nitrogen (TkN) Content was( 1113.1±382.5 )μg/g and average total phosphorus (TP) content was(567.2 ± 223.3)μg/g, and both were much higher than those of similar estuaries in China and elsewhere. Average nitrogen and phosphorus tended to be higher inside than outside the bay,higher at aquaculture than non-aquacuhure areas,and higher at fish-cage culture than oyster culture areas,suggesting that large-scale mariculture inside the bay played an important role in the eutrophication of the Zhelin Bay.Various forms of nitrogen and phosphorus concentrations were higher during the warm season (July--September),which was due to the increased decomposition and concentration of organic matter resulted from the fast growth and high mortality of the cultured species.Compared with July 2002,TkN and TP contents were much higher in July 2003,in consonance with the eut~'ophication of the Zhelin Bay.Because exchangeable phosphorus ( Ex-P),iron-bounded phos-phorus (Fe-P) and organic phosphorus (OP) combined accounted for 34.3% of the TP and authigenie phosphorus (Au-P) ac

  9. Biogeochemical redox cycling of arsenic in mine-impacted lake sediments and co-existing pore waters near Giant Mine, Yellowknife Bay, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, C.F. [Queen' s University, Department of Geological Sciences and Geological Engineering, Kingston, K7L 3N6 (Canada); Jamieson, H.E., E-mail: jamieson@geol.queensu.ca [Queen' s University, Department of Geological Sciences and Geological Engineering, Kingston, K7L 3N6 (Canada); Kyser, T.K. [Queen' s University, Department of Geological Sciences and Geological Engineering, Kingston, K7L 3N6 (Canada); Praharaj, T.; Fortin, D. [University of Ottawa, Department of Earth Sciences, Ottawa, K1A 3N5 (Canada)

    2010-02-15

    Lacustrine sediments, submerged tailings, and their pore waters have been collected at several sites in Yellowknife Bay, Great Slave Lake, Canada, in order to investigate the biogeochemical controls on the remobilization of As from mining-impacted materials under different depositional conditions. Radiometric dating confirms that a mid-core enrichment of Pb, Zn, Cu and Sb corresponds to the opening of a large Au mine 60 a ago. This was evident even in a relatively remote site. Arsenic was enriched at mid-core, coincident with mining activity, but clearly exhibited post-depositional mobility, migrating upwards towards the sediment water interface (SWI) as well as down-core. Deep-water (15 m) Yellowknife Bay sediments that contain buried mine waste are suboxic, relatively organic-rich and abundant in microbes with As in pore waters and sediments reaching 585 {mu}g/L and 1310 mg/kg, respectively. Late summer pore waters show equal proportions of As(III) and As(V) (16-415 {mu}g/L) whereas late winter pore waters are dominated by As(III) (284-947 {mu}g/L). This can be explained by As(III) desorption mechanisms associated with the conversion of FeS to FeS{sub 2} and the reduction of As(V) to As(III) through the oxidation of dissolved sulfide, both microbially-mediated processes. Processes affecting As cycling involve the attenuating efficiency of the oxic zone at the SWI, sediment redox heterogeneity and the reductive dissolution of Fe(hydr)oxides by labile organic matter, temporarily and spatially variable.

  10. Processes influencing the transport and fate of contaminated sediments in the coastal ocean: Boston Harbor and Massachusetts Bay

    Science.gov (United States)

    Bothner, Michael H.; Butman, Bradford

    2007-01-01

    Most of the major urban centers of the United States including Boston, New York, Washington, Chicago, New Orleans, Miami, Los Angeles, San Francisco, and Seattle—are on a coast (fig. 1.1). All of these cities discharge treated sewage effluent into adjacent waters. In 2000, 74 percent of the U.S. population lived within 200 kilometers (km) of the coast. Between 1980 and 2002, the population density in coastal communities increased approximately 4.5 times faster than in noncoastal areas of the U.S. (Perkins, 2004). More people generate larger volumes of wastes, increase the demands on wastewater treatment, expand the area of impervious land surfaces, and use more vehicles that contribute contaminants to street runoff. According to the National Coastal Condition Report II (U.S. Environmental Protection Agency, 2005a), on the basis of coastal habitat, water and sediment quality, benthic index, and fish tissue, the overall national coastal condition is only poor to fair and the overall coastal condition in the highly populated Northeast is poor. Scientific information helps managers to prioritize and regulate coastal-ocean uses that include recreation, commercial fishing, transportation, waste disposal, and critical habitat for marine organisms. These uses are often in conflict with each other and with environmental concerns. Developing a strategy for managing competing uses while maintaining sustainability of coastal resources requires scientific understanding of how the coastal ocean system behaves and how it responds to anthropogenic influences. This report provides a summary of a multidisciplinary research program designed to improve our understanding of the transport and fate of contaminants in Massachusetts coastal waters. Massachusetts Bay and Boston Harbor have been a focus of U.S. Geological Survey (USGS) research because they provide a diverse geographic setting for developing a scientific understanding of the geology, geochemistry, and oceanography of

  11. Coastal circulation and sediment dynamics in Pelekane and Kawaihae Bays, Hawaii--measurements of waves, currents, temperature, salinity, turbidity, and geochronology: November 2010--March 2011

    Science.gov (United States)

    Storlazzi, Curt D.; Field, Michael E.; Presto, M. Katherine; Swarzenski, Peter W.; Logan, Joshua B.; Reiss, Thomas E.; Elfers, Timothy C.; Cochran, Susan A.; Torresan, Michael E.; Chezar, Hank

    2012-01-01

    Coral reef communities on the Island of Hawaii have been heavily affected by the construction of Kawaihae Harbor in the 1950s and by subsequent changes in land use in the adjacent watershed. Sedimentation and other forms of land-based pollution have led to declines in water quality and coral reef health over the past two decades (Tissot, 1998). Erosion mitigation efforts are underway on land, and there is a need to evaluate the impact of these actions on the adjacent coastal ecosystem. The Kohala Center and Kohala Watershed Partnership was awarded $2.69 million from the National Oceanographic and Atmospheric Administration’s (NOAA) Restoration Center as part of the American Recovery and Reinvestment Act of 2009 to stabilize soil and improve land-use practices in the Pelekane Bay watershed. The grant allowed the Kohala Watershed Partnership to implement various upland watershed management activities to reduce land-based sources of pollution into Pelekane Bay. However, a number of questions must be answered in order to: (1) evaluate the effectiveness of the terrestrial watershed remediation efforts; (2) understand the potential of the local marine ecosystem to recover; and (3) understand the potential threat that existing mud deposits in the bay pose to adjacent, relatively pristine coral reef ecosystems. The goal of this experiment was to help address these questions and establish a framework to evaluate the success of the Kohala Watershed Partnership restoration efforts. This research program will also provide resource managers with information relevant to other watershed restoration efforts currently being planned in neighboring watersheds. This project involved an interdisciplinary team of coral reef biologists from the University of Hawaii Coral Reef Assessment and Monitoring Program, who focused on the impact of sedimentation on the biota of Pelekane Bay, and a team of geologists and oceanographers from the U.S. Geological Survey (USGS), who focused on the

  12. Coastal circulation and sediment dynamics in Pelekane and Kawaihae Bays, Hawaii--measurements of waves, currents, temperature, salinity, turbidity, and geochronology: November 2010--March 2011

    Science.gov (United States)

    Storlazzi, Curt D.; Field, Michael E.; Presto, M. Katherine; Swarzenski, Peter W.; Logan, Joshua B.; Reiss, Thomas E.; Elfers, Timothy C.; Cochran, Susan A.; Torresan, Michael E.; Chezar, Hank

    2012-01-01

    Coral reef communities on the Island of Hawaii have been heavily affected by the construction of Kawaihae Harbor in the 1950s and by subsequent changes in land use in the adjacent watershed. Sedimentation and other forms of land-based pollution have led to declines in water quality and coral reef health over the past two decades (Tissot, 1998). Erosion mitigation efforts are underway on land, and there is a need to evaluate the impact of these actions on the adjacent coastal ecosystem. The Kohala Center and Kohala Watershed Partnership was awarded $2.69 million from the National Oceanographic and Atmospheric Administration’s (NOAA) Restoration Center as part of the American Recovery and Reinvestment Act of 2009 to stabilize soil and improve land-use practices in the Pelekane Bay watershed. The grant allowed the Kohala Watershed Partnership to implement various upland watershed management activities to reduce land-based sources of pollution into Pelekane Bay. However, a number of questions must be answered in order to: (1) evaluate the effectiveness of the terrestrial watershed remediation efforts; (2) understand the potential of the local marine ecosystem to recover; and (3) understand the potential threat that existing mud deposits in the bay pose to adjacent, relatively pristine coral reef ecosystems. The goal of this experiment was to help address these questions and establish a framework to evaluate the success of the Kohala Watershed Partnership restoration efforts. This research program will also provide resource managers with information relevant to other watershed restoration efforts currently being planned in neighboring watersheds. This project involved an interdisciplinary team of coral reef biologists from the University of Hawaii Coral Reef Assessment and Monitoring Program, who focused on the impact of sedimentation on the biota of Pelekane Bay, and a team of geologists and oceanographers from the U.S. Geological Survey (USGS), who focused on the

  13. A chemostratigraphic method to determine the end of impact-related sedimentation at marine-target impact craters (Chesapeake Bay, Lockne, Tvären)

    Science.gov (United States)

    Ormö, Jens; Hill, Andrew C.; Self-Trail, Jean M.

    2010-01-01

    To better understand the impact cratering process and its environmental consequences at the local to global scale, it is important to know when in the geological record of an impact crater the impact-related processes cease. In many instances, this occurs with the end of early crater modification, leaving an obvious sedimentological boundary between impactites and secular sediments. However, in marine-target craters the transition from early crater collapse (i.e., water resurge) to postimpact sedimentation can appear gradual. With the a priori assumption that the reworked target materials of the resurge deposits have a different chemical composition to the secular sediments we use chemostratigraphy (δ13Ccarb, %Corg, major elements) of sediments from the Chesapeake Bay, Lockne, and Tvären craters, to define this boundary. We show that the end of impact-related sedimentation in these cases is fairly rapid, and does not necessarily coincide with a visual boundary (e.g., grain size shift). Therefore, in some cases, the boundary is more precisely determined by chemostratigraphy, especially carbonate carbon isotope variations, rather than by visual inspection. It is also shown how chemostratigraphy can confirm the age of marine-target craters that were previously determined by biostratigraphy; by comparing postimpact carbon isotope trends with established regional trends.

  14. Paleoenvironment interpretation of a 1760 years B.P. old sediment in a mangrove area of the Bay of Guanabara, using pollen analysis

    Directory of Open Access Journals (Sweden)

    Barth Ortrud M.

    2006-01-01

    Full Text Available A sediment sample was obtained at 122 cm from the top of a drilling core in the Guapimirim mangrove, Bay of Guanabara, and analyzed using pollen analysis. This muddy core reached a sandy ground at 133 cm. 14C datation got the age of 1760 ? 50 years B.P. The most frequent pollen grains were mangrove species of Rhizophora mangle, Laguncularia racemosa and Avicennia schaueriana. "Restinga" and tropical rain forest vegetation was recognized behind the mangrove. After the last sea transgression at 2500 years B.P., the water level lowered to its actual size, allowing the installation of this mangrove.

  15. 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.

  16. Wind-enhanced resuspension in the shallow waters of South San Francisco Bay: Mechanisms and potential implications for cohesive sediment transport

    Science.gov (United States)

    Brand, Andreas; Lacy, Jessica R.; Hsu, Kevin; Hoover, Daniel; Gladding, Steve; Stacey, Mark T.

    2010-01-01

    We investigated the driving forces of sediment dynamics at the shoals in South San Francisco Bay. Two stations were deployed along a line perpendicular to a 14 m deep channel, 1000 and 2000 m from the middle of the channel. Station depths were 2.59 and 2.19 m below mean lower low water, respectively. We used acoustic Doppler velocimeters for the simultaneous determination of current velocities, turbulence, sediment concentration and fluxes. Maximum current shear velocities were 0.015 m s−1 at the station further from the channel (closer to the shore) and 0.02 m s−1 at the station closer to the channel. Peak wave-induced shear velocities exceeded 0.015 m s−1 at both stations. Maximum sediment concentrations were around 30 g m−3 during calm periods (root mean square wave height −3 and sediment fluxes were 5 times higher than in calm conditions (0.02 g m−2 s−1 versus >0.10 g m−2 s−1) at the station further from the channel 0.36 m above the bed. Closer to the channel, sediment concentrations and vertical fluxes due to wind wave resuspension were persistently lower (maximum concentrations around 50 g m−3 and maximum fluxes around 0.04 g m−2 s−1). Most resuspension events occurred during flood tides that followed wave events during low water. Although wave motions are able to resuspend sediment into the wave boundary layer at low tide, the observed large increases in sediment fluxes are due to the nonlinear interaction of wind waves and the tidal currents.

  17. A new depositional model for glacial sediments in Killiney Bay during the Late Devensian deglaciation - East Central Ireland

    Science.gov (United States)

    Clerc, S.; Portier, E.; Buoncristiani, J. F.

    2009-04-01

    During the last glaciation in northwestern Europe, major studies are consistent with the hypothesis of an ice-stream flowing southward in the Irish Sea Basin, in connection with tributary flows on the eastern of the Irish Cap. During deglaciation, sediment deposition processes are predominant, leaving a record of glacially influenced environments. Evidence of such deposits still remains on the coast of the UK and Ireland today. Although these deposits have been studied for many decades, their depositional environment is still under debate and interpretations are evolving, together with new concepts. The present work focuses on the study of the Killiney Bay section, South Dublin, located in a topographic depression, expected to be a former subglacial tunnel valley in connection with an offshore canyon in the Irish Sea. Geometry and architecture have been approached by using panoramic photographs. In addition, fifteen detailed logs describe the stratigraphic succession, erosive surfaces and variations of small-scale sedimentary features. Seven Facies Associations were defined and used to reconstruct depositional environments. Although the section is affected by glaciotectonic deformation, primary sedimentological figures are well preserved. Within the section, a 600m long depression has been observed, in which a Gilbert-type delta has developed. Laterally, this delta evolves into prograding sheet-like structures interpreted as subaqueous fans. The corresponding facies association is composed of four main facies: -Matrix-supported coarse-grained facies (granules to cobbles) arranged in prograding sheet-like structures (dip angle 5-9° N160). -Massive sand to diffusely graded sand. -Coarse-to-medium sand facies with long wavelength ripples (1-2m), oriented N160. -Medium-to-coarse sand with climbing ripples and current ripples. These facies associations are characteristic of subaqueous (probably glaciolacustrine) environments. The transition from delta to fan delta has

  18. Distribution and biological effects of agricultural chemicals and other environmental contaminants in the sediments of Back Bay, Virginia

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Back Bay is the northernmost extension of the Albemarle- Pamlico-Currituck Sound estuary. It is located entirely within the city limits of Virginia Beach, Virginia....

  19. Sediment transport and deposition during extreme sea storm events at the Salerno Bay (Tyrrhenian Sea: comparison of field data with numerical model results

    Directory of Open Access Journals (Sweden)

    F. Budillon

    2006-01-01

    Full Text Available Seismic stratigraphy and core litho-stratigraphy in the Salerno Bay inner shelf (Southern Tyrrhenian Sea reveal significant storm deposition episodes over the last 1 ky. Three major events are preserved as decimetre thick silt/sand layers bounded at their base by erosional surfaces and sealed in the muddy marine sequences between 25 and 60 m of depth. Geochronology and chrono-stratigraphy on core sediment point towards a recurrence of major sea storms between 0.1 and 0.3 ky and put the last significant event in the 19th century, when no local meteorological time series is available. A modelling of extreme sea-storms with a return period of about 0.1 ky is here proposed based on historical hindcast and aims at explaining the occurrence of such unusual deep and thick sand deposits in the northern sector of the bay. Results highlight the vulnerability of the northern coast of the Salerno Bay to the south western sea storms which can drive waves up to about 8 m high and wave period of about 13 s. With these conditions an intense combined flow current is formed and might account for winnowing fine sand down to the depth of 40 m at least. The numerical model thus confirms a possible sand transport in the bottom boundary layer due to wave-current interaction and could corroborate the interpretation of the most recent sand layers, included in the cores, as being generated under extreme sea storm conditions.

  20. Polychlorinated biphenyls (PCBs) and Polybrominated Diphenyl Ethers (PBDEs) in surface sediments from Monastir Bay (Tunisia, Central Mediterranean): occurrence, distribution and seasonal variations.

    Science.gov (United States)

    Nouira, Taoufik; Risso, Christine; Chouba, Lassaad; Budzinski, Hélène; Boussetta, Hamadi

    2013-09-01

    An assessment of PCB and PBDE contamination of surface sediments in Monastir Bay was carried out in two contrasted seasons of the year. Samples were collected from 5 sites and analyzed for the ∑7 marker PCBs (i.e. PCBs 28, 52, 101, 118, 138, 153 and 180) and ∑4 PBDE congeners (PBDEs 47, 99, 119 and 153) by GC/ECD. Concentrations of both PCBs and PBDEs showed seasonal variations. PCB concentrations were in the range of 3.1-9.3 ng g(-1) and 1.1-8.1 ng g(-1) in wet and dry season respectively, and sediments were considered moderately contaminated with PCBs. All PCBs analyzed were detected in surface sediments. PCB 153 and 52 congeners showed the highest relative abundance in both winter and summer. PBDE concentrations ranged from not detect to 0.1 ng g(-1), with only BDE-47 congener detected in sediments and only in winter. Analysis of spatial and seasonal variations indicated that PCB distribution is governed by hydrodynamics and temporal variability of inputs. While the PCB contamination appeared to be mainly land-based, PBDEs are suspected to originate from atmospheric deposition.

  1. Characterization of streamflow, suspended sediment, and nutrients entering Galveston Bay from the Trinity River, Texas, May 2014–December 2015

    Science.gov (United States)

    Lucena, Zulimar; Lee, Michael T.

    2017-02-21

    The U.S. Geological Survey (USGS), in cooperation with the Texas Water Development Board and the Galveston Bay Estuary Program, collected streamflow and water-quality data at USGS streamflow-gaging stations in the lower Trinity River watershed from May 2014 to December 2015 to characterize and improve the current understanding of the quantity and quality of freshwater inflow entering Galveston Bay from the Trinity River. Continuous streamflow records at four USGS streamflow-gaging stations were compared to quantify differences in streamflow magnitude between upstream and downstream reaches of the lower Trinity River. Water-quality conditions were characterized from discrete nutrient and sedi­ment samples collected over a range of hydrologic conditions at USGS streamflow-gaging station 08067252 Trinity River at Wallisville, Tex. (hereinafter referred to as the “Wallisville site”), approximately 4 river miles upstream from where the Trinity River enters Galveston Bay.Based on streamflow records, annual mean outflow from Livingston Dam into the lower Trinity River was 2,240 cubic feet per second (ft3/s) in 2014 and 22,400 ft3/s in 2015, the second lowest and the highest, respectively, during the entire period of record (1966–2015). During this study, only about 54 percent of the total volume measured at upstream sites was accounted for at the Wallisville site as the Trinity River enters Galveston Bay. This difference in water volumes between upstream sites and the Wallisville site indicates that at high flows a large part of the volume released from Lake Livingston does not reach Galveston Bay through the main channel of the Trinity River. These findings indicate that water likely flows into wetlands and water bodies surrounding the main channel of the Trinity River before reaching the Wallisville site and is being stored or discharged through other channels that flow directly into Galveston Bay.To characterize suspended-sediment concentrations and loads in

  2. A rapid procedure for the determination of thorium, uranium, cadmium and molybdenum in small sediment samples by inductively coupled plasma-mass spectrometry: Application in Chesapeake Bay

    Science.gov (United States)

    Zheng, Yen; Weinman, B.; Cronin, T.; Fleisher, M.Q.; Anderson, Robert F.

    2003-01-01

    This paper describes a rapid procedure that allows precise analysis of Mo, Cd, U and Th in sediment samples as small as 10 mg by using a novel approach that utilizes a "pseudo" isotope dilution for Th and conventional isotope dilution for Mo, Cd and U by ICP-MS. Long-term reproducibility of the method is between 2.5 and 5% with an advantage of rapid analysis on a single digestion of sediment sample and the potential of adding other elements of interest if so desired. Application of this method to two piston cores collected near the mouth of the Patuxent River in Chesapeake Bay showed that the accumulation of authigenic Mo and Cd varied in response to the changing bottom water redox conditions, with anoxia showing consistent oscillations throughout both pre-industrial and industrial times. Accumulation of authigenic U shows consistent oscillations as well, without any apparent increase in productivity related to anoxic trends. Degrees of Mo and Cd enrichment also inversely correlate to halophilic microfaunal assemblages already established as paleoclimate proxies within the bay indicating that bottom water anoxia is driven in part by the amount of freshwater discharge that the area receives. ?? 2002 Elsevier Science Ltd. All rights reserved.

  3. Distribution and sources of polycyclic aromatic hydrocarbons in sediments of the Mai Po Inner Deep Bay Ramsar Site in Hong Kong.

    Science.gov (United States)

    Zhao, Zhen-Ye; Chu, Yan-ling; Gu, Ji-Dong

    2012-08-01

    The concentration of total polycyclic aromatic hydrocarbons (∑PAHs) and the 16 US EPA priority individual PAH compounds were analyzed in surface sediments from the Mai Po Inner Deep Bay, Ramsar Site of Hong Kong from December 2001 to Jun 2005, to investigate the spatial variability of anthropogenic pollutants. ∑PAHs concentrations ranged from 36.5 to 256.3 ng g(-1) dry weight with an average of 148.9 ng g(-1), comparable to other urbanized areas of the world, and there was little difference among different sampling times from December 2001 to June 2005. Based on comparison to the results from earlier study, it appears that a decrease of total PAHs concentration has occurred since 1992. Meanwhile, the concentrations of ∑PAHs were positive correlated with total organic carbon contents except sites F and G, suggesting the characteristics of the sediment influences the distribution and concentration of PAHs. There was relatively a good relationship among the individual PAHs and the compounds of fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo[a]pyrene and indeno[cd]pyrene yielded a good correlation (r(2) > 0.5) with total PAHs. Principal component analysis and specific PAHs compound ratios (Phe/Ant vs. Flt/Pyr) indicate the pyrogenic origins, especially traffic exhausts, are the dominant sources of PAHs in the Mai Po Inner Deep Bay Nature Reserve.

  4. Microbial diversity of cold-seep sediments in Sagami Bay, Japan, as determined by 16S rRNA gene and lipid analyses.

    Science.gov (United States)

    Fang, Jiasong; Shizuka, Arakawa; Kato, Chiaki; Schouten, Stefan

    2006-09-01

    Microbial communities in Calyptogena sediment and microbial mats of Sagami Bay, Japan, were characterized using 16S rRNA gene sequencing and lipid biomarker analysis. Characterization of 16S rRNA gene isolated from these samples suggested a predominance of bacterial phylotypes related to Gammaproteobacteria (57-64%) and Deltaproteobacteria (27-29%). The Epsilonproteobacteria commonly found in cold seeps and hydrothermal vents were only detected in the microbial mat sample. Significantly different archaeal phylotypes were found in Calyptogena sediment and microbial mats; the former contained only Crenarchaeota clones (100% of the total archaeal clones) and the latter exclusively Euryarchaeota clones, including the anaerobic oxidation of methane archaeal groups ANME-2a and ANME-2c. Many of these lineages are as yet uncultured and undescribed groups of bacteria and archaea. Phospholipid fatty acid analysis suggested the presence of sulphate-reducing and sulphur-oxidizing bacteria. Results of intact glyceryl dialkyl glyceryl tetraether lipid analysis indicated the presence of nonthermophilic marine planktonic archaea. These results suggest that the microbial community in the Sagami Bay seep site is distinct from previously characterized cold-seep environments.

  5. Geologic columns for the ICDP-USGS Eyreville A and B cores, Chesapeake Bay impact structure: Sediment-clast breccias, 1096 to 444 m depth

    Science.gov (United States)

    Edwards, L.E.; Powars, D.S.; Gohn, G.S.; Dypvik, H.

    2009-01-01

    The Eyreville A and B cores, recovered from the "moat" of the Chesapeake Bay impact structure, provide a thick section of sediment-clast breccias and minor stratified sediments from 1095.74 to 443.90 m. This paper discusses the components of these breccias, presents a geologic column and descriptive lithologic framework for them, and formalizes the Exmore Formation. From 1095.74 to ??867 m, the cores consist of nonmarine sediment boulders and sand (rare blocks up to 15.3 m intersected diameter). A sharp contact in both cores at ??867 m marks the lowest clayey, silty, glauconitic quartz sand that constitutes the base of the Exmore Formation and its lower diamicton member. Here, material derived from the upper sediment target layers, as well as some impact ejecta, occurs. The block-dominated member of the Exmore Formation, from ??855-618.23 m, consists of nonmarine sediment blocks and boulders (up to 45.5 m) that are juxtaposed complexly. Blocks of oxidized clay are an important component. Above 618.23 m, which is the base of the informal upper diamicton member of the Exmore Formation, the glauconitic matrix is a consistent component in diamicton layers between nonmarine sediment clasts that decrease in size upward in the section. Crystalline-rock clasts are not randomly distributed but rather form local concentrations. The upper part of the Exmore Formation consists of crudely fining-upward sandy packages capped by laminated silt and clay. The overlap interval of Eyreville A and B (940-??760 m) allows recognition of local similarities and differences in the breccias. ?? 2009 The Geological Society of America.

  6. Variabilidad espacial y temporal en la hidrografía invernal del sistema de bahías frente a la VIII región (Chile centro-sur Spatial and temporal variability of winter hydrography in the bay system off the VIII region (central-south Chile

    Directory of Open Access Journals (Sweden)

    PATRICIA FAÚNDEZ-BÁEZ

    2001-12-01

    Full Text Available En la zona centro-sur de Chile (VIII región existe un sistema de bahías (~ 36°30'-37° S, que incluye las bahías de Concepción (BC, San Vicente (BSV y Coronel en el sector oriental del Golfo de Arauco (SOGA, conocido como un importante centro de desove y reclutamiento de especies de peces durante el período invernal. En el presente estudio se analizó la variabilidad hidrográfica (temperatura, salinidad y estratificación, en la dimensión espacial (dentro y entre bahías y temporal (entre años de muestreo, así como su relación con las condiciones meteorológicas (viento y precipitaciones y aporte fluvial (caudal de ríos, durante el período invernal (julio-agosto entre 1993 y 1996. A nivel superficial (1 m y estrato 1-10 m las tres bahías mostraron heterogeneidad espacial en las distribuciones de temperatura y salinidad, especialmente entre las zonas del saco y la boca. A este nivel, además, los menores valores de temperatura y salinidad ocurrieron generalmente en SOGA, la que además presentó una mayor estratificación por efecto de la presencia de aguas de mayor dilución (The central-south area of Chile (VIII region presents a system of bays (~36°30'-37º S, including the bays of Concepcion (BC, San Vicente (BSV and Coronel in the eastern boundary of the Gulf of Arauco (SOGA. This system has been recognized as an important center for the spawning and recruitment of fish species during the winter. In the present study the hydrographic variability (temperature, salinity and density, both in space (inside and between the bays and time (between sampling years, during the winter period (July-August between 1993 and 1996, was analyzed. As well, its relationship to the meteorological conditions (wind and rainfall and fluvial contribution (river discharge was explored. At the surface level (1 m and 1-10 m depth stratum, the three bays showed spatial heterogeneity in temperature and salinity distributions, especially between the inner

  7. Effects of shoreline discharge of iron mine tailings on a marine soft-bottom community in northern Chile.

    Science.gov (United States)

    Lancellotti, D A; Stotz, W B

    2004-02-01

    This study evaluates the magnitude and extension of the impact produced by the discharge of inert allochthonous materials, including clays and particulate iron, on macrobenthic soft-bottom assemblages in the subtidal zone of a coastal bay in north-central Chile. An average of 118 Ton h(-1) of finely divided solids were discharged into the rocky intertidal zone of the bay for a period of over 16 years, producing continuous turbidity in the water column and sedimentation in the subtidal zone. Data obtained four months before cessation of the discharge showed that the macrofauna present at 20 and 50 m depth in the bay suffered an important decrease in abundance and species richness, low diversity/high dominance, and deep changes in community structure related to the discharge. The faunal assemblages present at 110 m depth did not show effects from the discharge, suggesting that the impact was limited to the inner part of the bay. The impoverished faunal aggregates at 20 and 50 m depth showed exclusive domination by the Lumbrineris bifilaris (polychaete)-Diastylis tongoyensis (cumacean) association, representing a simple trophic guild of deposit feeders. The complete absence of opportunistic species such as capitellid, spionid, and/or cirratulid polychaetes may be associated with the turbidity and sedimentation levels in the bay.

  8. Impact of Hurricane Irene on Vibrio vulnificus and Vibrio parahaemolyticus concentrations in surface water, sediment and cultured oysters in the Chesapeake Bay, Maryland, USA

    Directory of Open Access Journals (Sweden)

    Kristi S Shaw

    2014-05-01

    Full Text Available To determine if a storm event (i.e., high winds, large volumes of precipitation could alter concentrations of Vibrio vulnificus and Vibrio parahaemolyticus in aquacultured oysters (Crassostrea virginica and associated surface water and sediment, this study followed a sampling timeline before and after Hurricane Irene impacted the Chesapeake Bay estuary in late August 2011. Aquacultured oysters were sampled from two levels in the water column: surface 0.3 m and near-bottom just above the sediment. Concentrations of each Vibrio spp. and associated virulence genes were measured in oysters with a combination of real-time PCR and most probable number enrichment methods, and in sediment and surface water with real-time PCR. While concentration shifts of each Vibrio species were apparent post-storm, statistical tests indicated no significant change in concentration change for either Vibrio species by location (surface or near bottom oysters or date sampled (oyster tissue, surface water and sediment concentrations. V. vulnificus in oyster tissue was correlated with total suspended solids (r=0.41, p=0.04, and V. vulnificus in sediment was correlated with secchi depth (r=-0.93, p< 0.01, salinity (r=-0.46, p=0.02, tidal height (r=-0.45, p=0.03, and surface water V. vulnificus (r=0.98, p< 0.01. V. parahaemolyticus in oyster tissue did not correlate with environmental measurements, but V. parahaemolyticus in sediment and surface water correlated with several measurements including secchi depth (r=-0.48, p=0.02[sediment]; r=-0.97 p< 0.01[surface water] and tidal height (r=-0.96. p< 0.01[sediment], r=-0.59,p< 0.01 [surface water]. The concentrations of Vibrio spp. were higher in oysters relative to other studies (average V. vulnificus 4x105 MPN g-1, V. parahaemolyticus 1x105 MPN g-1, and virulence-associated genes were detected in most oyster samples. This study provides a first estimate of storm-related Vibrio density changes in oyster tissues, sediment and

  9. Chesapeake Bay Tributary Strategies

    Science.gov (United States)

    Chesapeake Bay Tributary Strategies were developed by the seven watershed jurisdictions and outlined the river basin-specific implementation activities to reduce nutrient and sediment pollutant loads from point and nonpoint sources.

  10. Treated wastewater effluent as a source of pyrethroids and fipronil at Todos Santos Bay, Mexico: Its impact on sediments and organisms.

    Science.gov (United States)

    Hernández-Guzmán, Félix Augusto; Macías-Zamora, José Vinicio; Ramírez-Álvarez, Nancy; Alvarez-Aguilar, Arturo; Quezada-Hernández, Cristina; Fonseca, Ana Paula

    2017-06-03

    Pyrethroids are insecticides widely used to control pests and disease vectors in residential areas and agricultural lands. Pyrethroids are emerging pollutants, and their use is a growing concern because of their toxicity potential to aquatic organisms. Todos Santos Bay and the Punta Banda estuary, 2 coastal bodies located to the south of the Southern California Bight, were studied to establish a baseline of the current conditions of pollution by pyrethroids and fipronil. Eight pyrethroids, along with fipronil and its 2 metabolites, were determined in effluents from wastewater-treatment plants (n = 3), surface sediments (n = 32), and 3 locations with mussels (Mytilus californianus, n = 9). Bifenthrin, permethrin, and cypermethrin were the most common pyrethroids found in the study areas and were widespread in sediments, mussels, and wastewater-treated effluents. Fipronil and its metabolites were detected in mussels and wastewater-treated effluents only. Total pyrethroid concentrations in sediments ranged from 0.04 to 1.95 ng/g dry weight in the Punta Banda estuary (n = 13) and from 0.07 to 6.62 ng/g dry weight in Todos Santos Bay (n = 19). Moreover, total pyrethroids in mussels ranged from 1.19 to 6.15 ng/g wet weight. Based on the toxic unit data calculated for pyrethroids and fipronil for Eohaustorius estuarius and Hyalella azteca, little to no impact is expected to the benthic population structure. Environ Toxicol Chem 2017;9999:1-8. © 2017 SETAC. © 2017 SETAC.

  11. Sobrevivencia y crecimiento de post-larvas de Argopecten purpuratus (Lamarck, 1819 en Bahía Inglesa, Chile: efectos del origen, distribución en la bahía y bacterioflora larval Postlarval survival and growth of Argopecten purpuratus (Lamarck,1819 in Bahia Inglesa, Chile: effects of origin, distribution in the bay and larval bacterioflora

    Directory of Open Access Journals (Sweden)

    RUBÉN E. AVENDAÑO

    2001-09-01

    Full Text Available Argopecten purpuratus es uno de los recursos marinos de mayor importancia comercial en Chile. Una de las etapas críticas en el cultivo de esta especie, es el traspaso de las post-larvas al medio natural, ya que durante este período se produce un significativo descenso en el número de post-larvas. Los factores que provocan estas bajas sobrevivencias pueden ser diversos, pero aún son desconocidos. En el presente estudio se evaluó la incidencia en la sobrevivencia y crecimiento de las variables origen de las larvas, distribución de los colectores en diferentes estaciones de Bahía Inglesa, III región (27° 03' 24" S, 70° 51' 30" O y los cambios en la bacterioflora asociadas a las post-larvas. Los organismos utilizados en el estudio fueron obtenidas desde los "hatcheries" de Cultivos Marinos Internacionales (III región y Cultivos Guayacán (IV región. Los resultados del estudio indican claramente que la ubicación y origen de las post-larvas en la bahía incide en la sobrevivencia de éstas. Sin embargo, el crecimiento no es afectado por las variables estudiadas (P Argopecten purpuratus is one of the most commercially important marine resources in Chile. One of the most critical steps in the massive culture of this species is the transference of postlarvae from hatchery production to the sea where significant mortality regularly occurs. The factors behind this low survival rate are probably diverse, and are as yet unknown. In the present study, postlarval survival and growth was observed as a function of origin of postlarvae, distribution of postlarvae in the bay, and microbial loading of the postlarvae. Survival rates were measured for different sites in Bahia Inglesa, Chile (27° 03' 24" S, 70° 51' 30" W as well as changes in the bacterioflora of the postlarvae. Postlarvae utilized in the study were obtained from Cultivos Marinos Internacionales (III Región and Cultivos Guayacan (IV Región. Results of the study clearly indicated that

  12. Bioavailability assessment of toxic metals using the technique "acid-volatile sulfide (AVS)-simultaneously extracted metals (SEM)" in marine sediments collected in Todos os Santos Bay, Brazil.

    Science.gov (United States)

    Silva, Jucelino B; Nascimento, Rodrigo A; de Oliva, Sergio T; de Oliveira, Olívia M C; Ferreira, Sergio L C

    2015-10-01

    This paper reports the bioavailability of the metals (cadmium, copper, zinc, lead, and nickel) in sediment samples collected in seven stations from the São Paulo Estuary, Todos os Santos Bay, Brazil. The bioavailability was determined by employing the technique "acid-volatile sulfide (AVS) and simultaneously extracted metal (SEM)". The elements cadmium, copper, lead, and zinc were determined using differential pulse anodic stripping voltammetry (DPASV), while nickel was quantified utilizing electrothermal atomic absorption spectrometry (ET AAS). The accuracy of these methods was confirmed using a certified reference material of estuarine sediment (NIST 1646). The sulfide was quantified using potentiometry with selective electrode and the organic matter determination employing an indirect volumetric method using potassium dichromate and iron(II) sulfate solutions. The bioavailability of the metals was estimated by relationship between the concentration of AVS and the sum of the concentrations of the simultaneously extracted metals (ΣSEM), considering a significant toxicity when (ΣSEM)/(AVS) is higher than 1. The bioavailability values in the seven stations studied varied from 0.93 to 1.31 (June, 2014) and from 0.34 to 0.58 (September, 2014). These results demonstrated a critical condition of toxicity (bioavailability >1) in six of the seven sediment samples collected during the rainy season (June, 2014). In the other period (September, 2014), the bioavailability was always lower than 1 for all sediment samples collected in the seven stations. The individual values of the concentrations of the five metals were compared with the parameters PEL (probable effects level) and TEL (threshold effects level), which are commonly employed for characterization of ecological risk in environmental systems. This comparison revealed that all metals have concentrations lower than the PEL and only zinc and lead in some stations have contents higher than the TEL. The

  13. PAH-biodegradation potential of indigenous microorganisms: evidence from the respiratory activity of surface sediments in the Quanzhou Bay in China

    Institute of Scientific and Technical Information of China (English)

    GU Tihua; WANG Zhaoshou; TIAN Yun; HUANG Bangqin; ZHENG Tianling

    2009-01-01

    Seven stations were established in the Quanzhou Bay (24.73°-24.96°N, 118.50°-118.70°E) in China on three cruises to determine the concentrations of polycyclic aromatic hydrocarbons (PAHs) and the numbers of PAH-degrading bacteria in surface sediments. Assessing the biodegradation poten-tial of indigenous microorganisms by measuring the respiratory intensity with the addition of PAHs in sediment samples was also one of the aims of this study. The results show that the total PAH concentrations of the sediments were 99.23-345.53 ng/g dry weight (d.w.), and the PAHs compo-sition pattern in the sediments was dominated by phenanthrene, fluoranthene and pyrene. The numbers of phenanthrene, fluoranthene and pyrene-degrading bacteria during three cruises were 1.42×103-8.93×104 CFU/g d.w., 8.29×103-9.43×104 CFU/g d.w. and 7.05×103-9.43×4 CFU/g d.w., respectively. The addition of three model PAH compounds (phenanthrene, fluoranthene and pyrene) showed a great influence on the increasing of the microbial activity in the sediments. And there was a significant correlation among the change of respiratory activity, PAH concentration and the number of PAH-degrading bacteria. The change in respiratory activity under PAHs selective pressure could, to a certain extent, indicate the potential degradative activity of the PAH-degrading microbial community.

  14. Major and trace element geochemistry of Bay of Bengal sediments: Implications to provenances and their controlling factors

    Digital Repository Service at National Institute of Oceanography (India)

    Tripathy, G.R.; Singh, S.K.; Ramaswamy, V.

    –interglacial period. Factor analysis of these geochemical dataset ascertains dominant role of riverine supply of sediments in regulating the geochemistry of SK187/PC33 sediments. The Al-normalized major (K and Ti) and trace elemental (Cu and Cr) ratios of these marine...

  15. 博贺湾海域悬沙输移机制分析%Analyses of mechanism of suspended sediment transport in Bohe Bay

    Institute of Scientific and Technical Information of China (English)

    樊立东; 童朝锋; 孟艳秋

    2016-01-01

    According to measured hydrological and suspended sediment data from spring tides in Bohe Bay, the suspended sediment transport flux was divided into several dynamic items using the mechanism decomposition method, and the mechanism of suspended sediment transport was analyzed in terms of the advection sediment transport, tidal pumping effect, and vertical circulation transport. The results show that the Lagrangian residual current basically moves in the direction of the flood tide and its value increases with the distance from the shore. The Euler residual current has a value similar to the Lagrangian residual current, while the value of the Stokes residual current is close to zero. The advection is the leading factor affecting the suspended sediment transp