Science.gov

Sample records for estuarine system southern

  1. Chamber-Based Estimates of Methane Production in Coastal Estuarine Systems in Southern California

    NASA Astrophysics Data System (ADS)

    Brigham, B.; Lipson, D.; Lai, C.

    2008-12-01

    Wetland systems are believed to produce between 100 - 231 Tg CH4 yr-1 which is roughly 20% of global methane emissions. The uncertainty in methane emissions models stem from the lack of detailed information about methane gas production within regional wetland systems. The aim of this study is to report the range of methane fluxes observed along salinity gradients at two San Diego coastal wetland systems, the Tijuana Estuary (Tijuana River National Estuarine Research Reserve) and the Peñasquitos Lagoon (Torrey Pines State Park Reserve). Soil water samples are used to elucidate factors responsible for the observed variation in methane fluxes. Air samples were subsequently collected from the headspace of a static soil chamber and stored in pre- evacuated vials. Methane concentrations were analyzed within hours after collection by gas chromatography in the laboratory. The chemical and physical properties of the soil, including salinity, pH, redox potential and temperature are measured with a hand-held probe nearby soil collars. The biological properties of the soil, including dissolved organic carbon, nitrate, and ammonia levels are measured from soil water samples in the laboratory. We find that saline sites under direct tidal influence produced methane fluxes ranging from -3.10 to 9.10 (mean 2.18) mg CH4 m-2 day-1. We also find that brackish sites (0.6 to 3.2 ppt in salinity) with fresh water input from residential runoff at the Peñasquitos Lagoon produced methane fluxes ranging from 0.53 to 192.10 (mean 33.34) mg CH4 m-2 day-1. Sampling was done over the course of 5 weeks during August-September of 2008. We hypothesize that the contrasting methane fluxes found between the saline and the brackish sites is due primarily to the different salinity, and in turn sulfate levels found at the two sites. The reduction of sulfate to produce energy is more energetically favorable than the reduction of carbon dioxide to produce methane. Thus the presence of sulfate may act as

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

    NASA Astrophysics Data System (ADS)

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

    2013-09-01

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

  3. 15 CFR 921.3 - National Estuarine Research Reserve System biogeographic classification scheme and estuarine...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... biogeographic classification scheme and estuarine typologies. (a) National Estuarine Research Reserves are... biogeographic classification scheme is used to ensure that the National Estuarine Research Reserve System... 15 Commerce and Foreign Trade 3 2010-01-01 2010-01-01 false National Estuarine Research...

  4. 75 FR 59696 - National Estuarine Research Reserve System

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-28

    ... National Oceanic and Atmospheric Administration National Estuarine Research Reserve System AGENCY... Approval and Availability of Revised Management Plans for the following National Estuarine Research... management plans of the Arraigns Bay, RI National Estuarine Research Reserve and the Tijuana River,...

  5. 75 FR 49887 - National Estuarine Research Reserve System

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-16

    ... National Oceanic and Atmospheric Administration National Estuarine Research Reserve System AGENCY... Period for Revised Management Plans for the following National Estuarine Research Reserves: Narragansett... management plans of the Narragansett Bay, RI National Estuarine Research Reserve and the Tijuana, CA...

  6. Low mercury levels in marine fish from estuarine and coastal environments in southern China.

    PubMed

    Pan, Ke; Chan, Heidi; Tam, Yin Ki; Wang, Wen-Xiong

    2014-02-01

    This study is the first comprehensive evaluation of total Hg and methylmercury (MeHg) concentrations in wild marine fish from an estuarine and a coastal ecosystem in southern China. A total of 571 fish from 54 different species were examined. Our results showed that the Hg levels were generally low in the fish, and the Hg levels were below 30 ng g(-1) (wet weight) for 82% of the samples, which may be related to the reduced size of the fish and altered food web structure due to overfishing. Decreased coastal wetland coverage and different carbon sources may be responsible for the habitat-specific Hg concentrations. The degree of biomagnification was relatively low in the two systems. PMID:24292441

  7. 75 FR 4349 - National Estuarine Reserve System

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-27

    ...The National Oceanic and Atmospheric Administration, National Ocean Service, publishes this notice to re-open the solicitation period for the National Estuarine Research Reserve Land Acquisition and Construction Program FY10 to provide National Estuarine Research Reserve lead State agencies or designated universities in coastal States the opportunity to submit proposals for...

  8. 76 FR 2083 - National Estuarine Research Reserve System

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-12

    ... National Oceanic and Atmospheric Administration National Estuarine Research Reserve System AGENCY..., National Oceanic and Atmospheric Administration, U.S. Department of Commerce. ACTION: Notice of Public... Management, National Ocean Service, National Oceanic and Atmospheric Administration (NOAA), U.S....

  9. 78 FR 75548 - National Estuarine Research Reserve System

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-12

    ... National Oceanic and Atmospheric Administration National Estuarine Research Reserve System AGENCY..., National Oceanic and Atmospheric Administration, U.S. Department of Commerce ACTION: Notice of Approval of..., National Ocean Service, National Oceanic and Atmospheric Administration, U.S. Department of...

  10. Estuarine infill and coastal progradation, southern van diemen gulf, northern Australia

    NASA Astrophysics Data System (ADS)

    Woodroffe, C. D.; Mulrennan, M. E.; Chappell, J.

    1993-03-01

    There are several estuaries associated with the pronouncedly seasonal rivers which drain northwards from the Middle Proterozoic sandstone Arnhem Land plateau, and the Tertiary Koolpinyah land surface, into the macrotidal van Diemen Gulf, in the Northern Territory of Australia. The Holocene development of these, investigated in greatest detail for the South Alligator River with an upland catchment of > 10,000 km 2. through drilling, palynology and radiocarbon dating, comprises both estuarine infill and coastal progradation. Three phases of estuarine infill can be recognised: (i) a transgressive phase (8000-6800 years B.P.) of marine incursion; (ii) a big swamp phase (6800-5300 years B.P.) of widespread mangrove forest development; and (iii) a sinuous/cuspate phase of floodplain development since 5300 years B.P., during which the tidal river has meandered and reworked earlier estuarine sediments. Since 6000 years B.P., the South Alligator coastal plain has prograded at a decelerating rate, with two phases of chenier ridge formation. A similar pattern of estuarine infill, and decelerating coastal plain progradation, is demonstrated for the Adelaide and Mary Rivers, both with catchments of > 6000 km 2. The southern shore of van Diemem Gulf appears to have changed its overall position little during the last 2000 years. The major source for the clay, silt and fine sands which have infilled the estuary and coastal plain has been from seaward. Dispite the similarity of development, coastal sediment build up has had different effects on the morphology of each tidal river. The Adelaide has undergone a major diversion and no longer flows directly into van Diemen Gulf, but occupies a former fluvial course, and the Mary has been blocked entirely, and its former estuarine palaeochannels have been infilled with tide-transported sediment.

  11. Paleoenvironmental setting and description of an estuarine oyster reef in the Eocene of Patagonia, southern Argentina

    NASA Astrophysics Data System (ADS)

    Raising, Martín Rodríguez; Casadío, Silvio; Pearson, Nadine; Mángano, Gabriela; Buatois, Luis; Griffin, Miguel

    2014-12-01

    A middle Eocene Crassostrea sp. reef near Río Turbio, southwestern Patagonia (Argentina), represents the earliest record of an oyster reef associated with estuarine facies in the southern hemisphere, and also one of the few known worldwide occurring in Paleogene rocks. The reef grew in an outer estuary environment subject to periodic changes in salinity and may have reached a maturing phase. The Río Turbio reef - by its dimensions, geometry, and substrate lithology- would have been located in a tidal channel convergence area. This reef provides new evidence suggesting that estuaries served as refuges for Crassostrea populations allowing them to disperse into fully marine environments many times throughout the Cenozoic.

  12. 75 FR 60720 - National Estuarine Research Reserve System

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-01

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Estuarine Research Reserve System Correction In notice document 2010-24341 appearing on page 59696 in the issue of Tuesday, September 28, 2010 make...

  13. 15 CFR 921.3 - National Estuarine Research Reserve System biogeographic classification scheme and estuarine...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE OCEAN AND COASTAL RESOURCE MANAGEMENT NATIONAL ESTUARINE... chosen to reflect regional differences and to include a variety of ecosystem types. A...

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

    PubMed Central

    2014-01-01

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

  15. Impact of frontal systems on estuarine sediment and pollutant dynamics.

    PubMed

    Duck, R W; Wewetzer, S F

    2001-02-01

    In this paper, a brief description of frontal systems, their modes of occurrence and impact on the estuarine environment, is presented. Previous studies of estuarine fronts have largely focused on the water surface and within the water column. New observations in the Tay Estuary, Scotland have shown that the presence of fronts within the water column may be marked, not only by surface foam bands, but also by abrupt (i.e. non-gradational) changes in the underlying bedform morphology and/or sediment facies, as detected using side-scan sonar. This preliminary evidence suggests that fronts may exert a control, not only on the surface and intra-water column sediment and pollutant partitioning, but also on the distribution and persistence of bedload transport pathways. PMID:11258822

  16. Halogen Radicals Promote the Photodegradation of Microcystins in Estuarine Systems.

    PubMed

    Parker, Kimberly M; Reichwaldt, Elke S; Ghadouani, Anas; Mitch, William A

    2016-08-16

    The transport of microcystin, a hepatotoxin produced by cyanobacteria (e.g., Microcystis aeruginosa), to estuaries can adversely affect estuarine and coastal ecosystems. We evaluated whether halogen radicals (i.e., reactive halogen species (RHS)) could significantly contribute to microcystin photodegradation during transport within estuaries. Experiments in synthetic and natural water samples demonstrated that the presence of seawater halides increased quantum yields for microcystin indirect photodegradation by factors of 3-6. Additional experiments indicated that photoproduced RHS were responsible for this effect. Despite the fact that dissolved organic matter (DOM) concentrations decreased in more saline waters, the calculated photochemical half-life of microcystin decreased 6-fold with increasing salinity along a freshwater-estuarine transect due to the halide-associated increase in quantum yield. Modeling of microcystin photodegradation along this transect indicated that the time scale for RHS-mediated microcystin photodegradation is comparable to the time scale of transport. Microcystin concentrations decline by ∼98% along the transect when considering photodegradation by RHS, but only by ∼54% if this pathway were ignored. These results suggest the importance of considering RHS-mediated photodegradation in future models of microcystin fate in freshwater-estuarine systems. PMID:27447196

  17. 76 FR 40338 - National Estuarine Research Reserve System

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-08

    ...The Estuarine Reserves Division, Office of Ocean and Coastal Resource Management, National Ocean Service, National Oceanic and Atmospheric Administration (NOAA), U.S. Department of Commerce has approved the ACE Basin, SC National Estuarine Research Reserve and Old Woman Creek, OH National Estuarine Research Reserve Management Plan Revisions. The revised management plan for the ACE Basin, SC......

  18. 78 FR 26617 - National Estuarine Research Reserve System

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-07

    ...Notice is hereby given that the Estuarine Reserves Division, Office of Ocean and Coastal Resource Management, National Ocean Service, National Oceanic and Atmospheric Administration, U.S. Department of Commerce is announcing a thirty day public comment period for the Grand Bay, Mississippi National Estuarine Research Reserve Management Plan and the Delaware National Estuarine Research Reserve......

  19. Tidal variations in the Sundarbans Estuarine System, India

    NASA Astrophysics Data System (ADS)

    Chatterjee, Meenakshi; Shankar, D.; Sen, G. K.; Sanyal, P.; Sundar, D.; Michael, G. S.; Chatterjee, Abhisek; Amol, P.; Mukherjee, Debabrata; Suprit, K.; Mukherjee, A.; Vijith, V.; Chatterjee, Siddhartha; Basu, Anwesha; Das, Madhumita; Chakraborti, Saranya; Kalla, Aravind; Misra, Surja Kanta; Mukhopadhyay, Soumya; Mandal, Gopal; Sarkar, Kankan

    2013-08-01

    Situated in the eastern coastal state of West Bengal, the Sundarbans Estuarine System (SES) is India's largest monsoonal, macro-tidal delta-front estuarine system. It comprises the southernmost part of the Indian portion of the Ganga-Brahmaputra delta bordering the Bay of Bengal. The Sundarbans Estuarine Programme (SEP), conducted during 18-21 March 2011 (the Equinoctial Spring Phase), was the first comprehensive observational programme undertaken for the systematic monitoring of the tides within the SES. The 30 observation stations, spread over more than 3600 km2, covered the seven inner estuaries of the SES (the Saptamukhi, Thakuran, Matla, Bidya, Gomdi, Harinbhanga, and Raimangal) and represented a wide range of estuarine and environmental conditions. At all stations, tidal water levels (every 15 minutes), salinity, water and air temperatures (hourly) were measured over the six tidal cycles. We report the observed spatio-temporal variations of the tidal water level. The predominantly semi-diurnal tides were observed to amplify northwards along each estuary, with the highest amplification observed at Canning, situated about 98 km north of the seaface on the Matla. The first definite sign of decay of the tide was observed only at Sahebkhali on the Raimangal, 108 km north of the seaface. The degree and rates of amplification of the tide over the various estuarine stretches were not uniform and followed a complex pattern. A least-squares harmonic analysis of the data performed with eight constituent bands showed that the amplitude of the semi-diurnal band was an order of magnitude higher than that of the other bands and it doubled from mouth to head. The diurnal band showed no such amplification, but the amplitude of the 6-hourly and 4-hourly bands increased headward by a factor of over 4. Tide curves for several stations displayed a tendency for the formation of double peaks at both high water (HW) and low water (LW). One reason for these double-peaks was the HW

  20. Tidal changes in estuarine systems induced by local geomorphologic modifications

    NASA Astrophysics Data System (ADS)

    Picado, Ana; Dias, João M.; Fortunato, André B.

    2010-10-01

    Although rising global sea levels will affect the estuarine flooded areas over the coming decades, the local and regional-scale processes will also induce important changes in these coastal systems. The main aim of this work is to investigate possible tidal changes in estuarine systems induced by local geomorphologic modifications, analysing the particular case of Ria de Aveiro which is in risk of inundation. Located in the Portuguese west coast, this tidally driven lagoon has a large area of mostly abandoned salt pans, which are in progressive degradation caused by the lack of maintenance and by the strong currents which erode their protective walls. To explore possible tidal changes the hydrodynamic model ELCIRC was applied to Ria de Aveiro to simulate and analyse the impact in the lagoon hydrodynamics of this degradation which results in the enlargement of the lagoon flooded area. A high-resolution grid (grid spacing of the order of 1 m) was developed in order to represent the narrow channels adjacent to the salt pans. The hydrodynamic model was then successfully calibrated and assessed for skill for the Aveiro lagoon through comparison between measurements and model results and quantification of the numerical accuracy. The model was subsequently used to investigate the effect of the flooded lagoon area enlargement on tidal propagation in Ria de Aveiro. Simulations were performed for three geomorphologic configurations, representing the reference or present situation and two flooded scenarios. Results were compared through the analysis of tidal currents, tidal asymmetry and tidal prism. The increase of the lagoon flooded area results in an intensification of the tidal currents, tidal prism and tidal asymmetry. Results also indicate that the tidal prism further increases when the flooding depth increases. Otherwise, changes in tidal currents and in tidal asymmetry pattern are negligible with the increase of the flooded area depth. These results indicate that

  1. 78 FR 50038 - National Estuarine Research Reserve System

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-16

    ...Notice is hereby given that the Estuarine Reserves Division, Office of Ocean and Coastal Resource Management, National Ocean Service, National Oceanic and Atmospheric Administration, U.S. Department of Commerce is announcing a thirty day public comment period for the Wells, Maine National Estuarine Research Reserve Management Plan revision. Pursuant to 15 CFR Section 921.33(c), the revised......

  2. 78 FR 53732 - National Estuarine Research Reserve System

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-30

    ...Notice is hereby given that the Estuarine Reserves Division, Office of Ocean and Coastal Resource Management, National Ocean Service, National Oceanic and Atmospheric Administration, U.S. Department of Commerce approves the Grand Bay, Mississippi and the Delaware National Estuarine Research Reserve Management Plan Revisions. The revised management plans outline the administrative structure;......

  3. 76 FR 16620 - National Estuarine Research Reserve System

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-24

    ...Notice is hereby given that the Estuarine Reserves Division, Office of Ocean and Coastal Resource Management, National Ocean Service, National Oceanic and Atmospheric Administration (NOAA), U.S. Department of Commerce is announcing a thirty-day comment period for the revised management plans and boundary amendments of the ACE Basin, SC National Estuarine Research Reserve and Old Woman Creek,......

  4. Ecological and biological strategies of Etropus crossotus and Citharichthys spilopterus (Pleuronectiformes:Paralichthyidae) related to the estuarine plume, Southern Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Sánchez-Gil, Patricia; Yáñez-Arancibia, Alejandro; Tapia, Margarito; Day, John W.; Wilson, Charles A.; Cowan, James H., Jr.

    2008-04-01

    Differences in the biological and ecological strategies of two tropical flatfishes, Etropus crossotus (fringed flounder) and Citharichthys spilopterus (bay whiff) are discussed. The comparative analysis was based on the seasonal distribution of relative abundance of the two species and flatfish movements utilizing estuarine plume influenced areas as part of their life cycles. Growth parameters of the von Bertalanffy equation and recruitment were estimated (FISAT software) to compare life cycle patterns. The recruitment patterns illustrate the key difference between "estuarine-dependent" and "estuarine-related" nekton strategies. Both species have a short life cycle with a continuous recruitment activity. E. crossotus is an estuarine-related species, with two recruitment pulses ( winter frontal season), in the estuarine plume on the shelf. C. spilopterus is an estuarine-dependent species, with a main recruitment pulse during the rainy season in the estuarine plume, and a residual secondary pulse inside the adjacent estuarine system (Terminos Lagoon). The results show that the ecological success of these tropical coastal marine flatfish, with similar biological patterns, is based upon the sequential use (in time and space) of estuarine plume influenced habitats, suggesting that fish migration to shallow waters is related to food availability changes as a strategy towards optimum recruitment.

  5. Ecology of the Apalachicola Bay System: an estuarine profile

    SciTech Connect

    Livingston, R.J.

    1984-09-01

    Twelve years of studies in the Apalachicola Bay system are reviewed. Included are data on geography, hydrology, chemistry, geology, and biology. The system is part of a major drainage area including four rivers and associated wetlands in Georgia, Alabama, and Florida. It is a shallow coastal lagoon fringed by barrier islands and dominated by wind effects and tidal currents. River bottomlands (channels, sloughs, swamps, and backwater) and periodically flooded lowlands are important components. Principal influences on biological processes are basin physiography, river flow, nutrient input, and salinity. Water quality is affected by periodic wind and tidal influences and freshwater inflows. The system is in a relatively natural state, though hardly pristine. But economic development and population growth are beginning to threaten it. The area's economic and ecological importance as a food producer and shelter for diverse species has inspired a movement to protect its natural resources, including State and Federal land-purchase programs, integration of county land-use regulations into a comprehensive development, and creation of the Apalachicola River and Bay National Estuarine Sanctuary. 49 figs., 31 tabs.

  6. Benthic assemblages of a temperate estuarine system in South America: Transition from a freshwater to an estuarine zone

    NASA Astrophysics Data System (ADS)

    Cortelezzi, Agustina; Capítulo, Alberto Rodrigues; Boccardi, Lucía; Arocena, Rafael

    2007-12-01

    The objectives of the present study were to describe the species composition, diversity and distribution of the zoobenthic assemblages, to estimate the abundance and biomass of the dominant species, and to identify the main environmental factors determining the distribution patterns of the invertebrates from a freshwater to an estuarine zone in a temperate estuary of South America. The Río de la Plata estuary is a microtidal system characterized by a high concentration of suspended solids. Fifty-three taxa of meso- and macro-invertebrates were identified in the samples collected during November and December 2001. Molluscs, annelids, crustaceans and nematodes were found at 90% of the sampling sites. Molluscs comprised up to about 90% of the total zoobenthos biomass: the remaining percentage corresponded mainly to annelids and less to nematodes and crustaceans. An ecocline along the salinity gradient could be observed for the benthic assemblages from the freshwater to the estuarine zone in Rio de la Plata. A Canonical Correspondence Analysis shows that results from sampling sites in the outer zone were strongly related to salinity, depth and pH and less to oxygen and percentage of clay. The results from stations in the inner zone, and part of the middle zone, were mainly related to the occurrence of sand and contents of NH 4+-N, NO 3--N, and PO 43--P.

  7. Determination of fish trophic levels in an estuarine system

    NASA Astrophysics Data System (ADS)

    Pasquaud, S.; Pillet, M.; David, V.; Sautour, B.; Elie, P.

    2010-01-01

    The concept of trophic level is particularly relevant in order to improve knowledge of the structure and the functioning of an ecosystem. A precise estimation of fish trophic levels based on nitrogen isotopic signatures in environments as complex and fluctuant as estuaries requires a good description of the pelagic and benthic trophic chains and a knowledge of organic matter sources at the bottom. In this study these points are considered in the case of the Gironde estuary (south west France, Europe). To obtain a good picture of the food web, fish stomach content analyses and a bibliographic synthesis of the prey feeding ecology were carried out. Fish trophic levels were calculated from these results and δ 15N data. The feeding link investigation enabled us to identify qualitatively and quantitatively the different preys consumed by each fish group studied, to distinguish the prey feeding on benthos from those feeding on pelagos and to characterize the different nutritive pools at the base of the system. Among the species studied, only Liza ramada and the flatfish ( Platichthys flesus and Solea solea) depend mainly on benthic trophic compartments. All the other fish groups depend on several trophic (benthic and/or pelagic) sources. These results enabled us to correct the calculation of fish trophic levels which are coherent with their feeding ecology data obtained from the nitrogen isotopic integrative period. The present work shows that trophic positions are linked with the feeding ecology of fish species and vary according to individual size. Ecological data also allow the correction of the isotopic data by eliminating absurd results and showing the complementarity of the two methods. This work is the first to consider source variability in the fish food web. This is an indispensable step for trophic studies in a dynamic environment. The investigation of matter fluxes and recycling processes at the food web base would provide a useful improvement in future

  8. Characterization Methods for Small Estuarine Systems in the Mid-Atlantic Region of the United States

    EPA Science Inventory

    Various statistical methods were applied to spatially discrete data from 14 intensively sampled small estuarine systems in the mid-Atlantic U.S. The number of sites per system ranged from 6 to 37. The surface area of the systems ranged from 1.9 to 193.4 km2. Parameters examined ...

  9. Carbon and nitrogen isotope ratios of juvenile winter flounder as indicators of inputs to estuarine systems

    EPA Science Inventory

    Stable carbon and nitrogen isotope ratios were measured in the muscle tissues of young-of-the-year (YOY) winter flounder, Pseudopleuronectes americanus, collected from several estuarine systems along the coast of Rhode Island, USA. These systems included three coastal lagoons (Ni...

  10. NUTRIENT SOUIRCES, TRANSPORT, AND FATE IN COUPLED WATERSHED-ESTUARINE SYSTEMS OF COASTAL ALABAMA

    EPA Science Inventory

    The processes regulating sources, transport, and fate of nutrients were studied in 3 coupled watershed-estuarine systems that varied mainly by differences in the dominant land use-land cover (LULC), i.e. Weeks Bay -- agriculture, Dog River -- urban, and Fowl River -- forest. Mea...

  11. FIELD VALIDATION OF MULTI-SPECIES LABORATORY TEST SYSTEMS FOR ESTUARINE BENTHIC COMMUNITIES

    EPA Science Inventory

    The major objective of the project was to determine the validity of using multispecies laboratory systems to evaluate the response of estuarine benthic communities to an introduced stress. In a 5-year period, experiments in Apalachicola Bay, Florida, and the York River, Virginia,...

  12. Trace fossil assemblages in the tide-dominated estuarine system: Ameki Group, south-eastern Nigeria

    NASA Astrophysics Data System (ADS)

    Ekwenye, O. C.; Nichols, G.; Okogbue, C. O.; Mode, A. W.

    2016-06-01

    A systematic ichnological analysis with sedimentological study of the Eocene Ameki Group in south-eastern Nigeria, was conducted to infer depositional and biogenic processes operating during basin fill, identify discontinuities using substrate controlled ichnofacies, and identify the paleocological conditions that affected the diversity of the trace fossils. The Ameki Group represents a tide-dominated estuarine system characterised by a range of trace fossils assemblages. Eighteen individual ichnogenera and nineteen ichnospecies observed in the study area, were grouped into six recurring ichnofacies namely Scoyenia, Psilonichnus, Skolithos, Cruziana, Glossifungites and Teredolites. Skolithos and Cruziana ichnofacies are predominant in the estuarine deposits indicating that the sedimentary successions of the Eocene are dominantly of moderate to high energy marginal marine environments. The estuarine deposits (senus stricto) were controlled by low to fluctuating salinity levels, high sedimentation rate and fluctuating hydrodynamic energy. These resulted in the occurrence of low diversity of Scoyenia and Teredolites ichnofacies and low to moderate ichnodiversity of mixed Skolithos and depauperate Cruziana ichnofacies. Low levels of dissolved oxygen in quiescent water-embayment (open estuarine) resulted in low diversity of impoverished Cruziana ichnofacies. Glossifungites ichnofacies marked an amalgamated sequence boundary/marine flooding and an initial flooding surface at the base of the tidally influenced fluvial deposits.

  13. Heavy metals and TPH effects on microbial abundance and diversity in two estuarine areas of the southern-central coast of São Paulo State, Brazil.

    PubMed

    Pinto, Aline Bartelochi; Pagnocca, Fernando Carlos; Pinheiro, Marcelo Antonio Amaro; Fontes, Roberto Fioravanti Carelli; de Oliveira, Ana Júlia Fernandes Cardoso

    2015-07-15

    Coastal areas may be impacted by human and industrial activities, including contamination by wastewater, heavy metals and hydrocarbons. This study aimed to evaluate the impact of hydrocarbons (TPH) and metals on the microbiota composition and abundance in two estuarine systems in the coast of São Paulo: the Santos (SE) and Itanhaém (IE) estuaries. The SE was found to be chronically contaminated by heavy metals and highly contaminated by hydrocarbons. This finding was correlated with the increased density of cyanobacteria in sediments and suggests the possible use of cyanobacteria for bioremediation. These contaminants influence the density and composition of estuarine microbiota that respond to stress caused by human activity. The results are troubling because quantitative and qualitative changes in the microbiota of estuarine sediments may alter microbiological processes such as decomposition of organic matter. Moreover, this pollution can result in damage to the environment, biota and human health. PMID:26021289

  14. Nursery use patterns of commercially important marine fish species in estuarine systems along the Portuguese coast

    NASA Astrophysics Data System (ADS)

    Vasconcelos, R. P.; Reis-Santos, P.; Maia, A.; Fonseca, V.; França, S.; Wouters, N.; Costa, M. J.; Cabral, H. N.

    2010-03-01

    Analysing the estuarine use patterns of juveniles of marine migrant fish species is vital for identifying important sites for juveniles as well as the basic environmental features that characterize these sites for different species. This is a key aspect towards understanding nursery function. Various estuarine systems along the Portuguese coast (Minho, Douro, Ria de Aveiro, Mondego, Tejo, Sado, Mira, Ria Formosa and Guadiana) were sampled during Spring and Summer 2005 and 2006. Juveniles of commercially important marine fish species Solea solea, Solea senegalensis, Platichthys flesus, Diplodus vulgaris and Dicentrarchus labrax, predominantly 0-group individuals, were amongst the most abundant species and had distinct patterns of estuarine use as well as conspicuous associations with several environmental features. Juvenile occurrence and density varied amongst estuaries and sites within them, and differed with species. Sites with consistently high juvenile densities were identified as important juvenile sites (i.e. putative nursery grounds). Through generalized linear models (GLM), intra-estuarine variation in occurrence and density of each of the individual species was largely explained by environmental variables (temperature; salinity; depth; percentage of mud in the sediment; presence of seagrass; importance of intertidal areas; relative distance to estuary mouth; macrozoobenthos densities; and latitude). Decisive environmental factors defining important sites for juveniles varied depending on the system as a result of different environmental gradients, though there were common dominant features for each species regardless of the estuary considered. Analysed environmental variables in the GLM also accounted for inter-estuarine variation in species' occurrence and density. In several estuaries, the identified important juvenile sites were used by many of these species simultaneously and may be of increased value to both management and conservation. Overall, the

  15. Regional assessment of marine and estuarine sediment toxicity in Southern California, USA.

    PubMed

    Greenstein, Darrin; Bay, Steven; Jacobe, Matthew; Barton, Carlita; Sakamoto, Ken; Young, Diana; Ritter, Kerry; Schiff, Ken

    2013-02-01

    Sediment toxicity was investigated at 222 stations in the Southern California Bight (SCB) during 2008. This represented the first time that assessment methods established by California's new Sediment Quality Objectives program were employed in a survey of this scale. The goal was to determine the extent and magnitude of sediment toxicity in the SCB, how toxicity compared among specific environments, and whether toxicity has changed over the last decade. Two toxicity tests were used: the 10-day amphipod whole sediment survival test with Eohaustorius estuarius and a 48-h embryo development test with the mussel Mytilus galloprovincialis exposed at the sediment-water interface. Less than 1 % of the area of the SCB was found to be toxic to the amphipod test. No toxicity was found in offshore stations, but 14 % of embayment areas were toxic to the amphipods. The mussel test identified 13 % of the embayment areas to be toxic. Estuary and marina locations had the greatest areal extent of toxicity for both tests. The two toxicity methods agreed that sediments were not toxic at over half of the stations tested. The mussel test showed a greater magnitude of response than the amphipod. Sediment toxicity was shown to have declined in both extent and magnitude from levels measured in 1998 and 2003. PMID:22638724

  16. ESTIMATION OF INHERENT OPTICAL PROPERTIES AND THE WATER QUALITY COMPONENTS IN THE NEUSE RIVER-PAMLICO SOUND ESTUARINE SYSTEM

    EPA Science Inventory

    Field observations carried out in the Neuse River-Pamlico Sound Estuarine System (NRE-PS), North Carolina, USA were used to develop optical algorithms for assessing inherent optical properties, IOPs (absorption and backscattering) associated with water quality components (WQC).

  17. Distribution of butyltin compounds in Brazil's southern and southeastern estuarine ecosystems: assessment of spatial scale and compartments.

    PubMed

    Dos Santos, Dayana Moscardi; Turra, Alexander; de Marchi, Mary Rosa Rodrigues; Montone, Rosalinda Carmela

    2016-08-01

    Butyltin compounds (BTs), including tributyltin (TBT) and its degradation products, dibutyltin and monobutyltin, have been found in a diversity of aquatic systems and causing toxic effects in target and nontarget organisms. They enter in coastal systems through different sources (as antifouling paints, industrial effluents, etc.) where they interact with biotic and abiotic components, and their distribution is commonly determined by the morphological and hydrodynamic conditions of the coastal systems. In this study, we discuss the contamination by BTs on a spatial scale (eight estuaries with three subareas each) and in different compartments of the estuaries (sediments, suspended particulate matter (SPM), and estuarine catfish tissues (liver and gills). Lower concentrations of BTs were found in the sediments (n.d. to 338 ng g(-1)) in comparison to studies before a ban of TBT in antifouling paints was enacted, mostly indicating an old input or preservation related with sediment properties and composition. For SPM samples (n.d. to 175 ng L(-1)) as well as in fish tissues (n.d. to 1426 ng g(-1)), the presence of these compounds was frequent, especially in the fish due to their movement throughout the estuaries and the potential to assess point sources of BTs. These results indicate that BTs persist in the environment, with variation in amounts between investigated estuaries and even at locations inside the same estuary, because of ideal preservation conditions, transport to remote areas, and input from different sources. PMID:27151240

  18. Sponge-rhodolith interactions in a subtropical estuarine system

    NASA Astrophysics Data System (ADS)

    Ávila, Enrique; Riosmena-Rodríguez, Rafael; Hinojosa-Arango, Gustavo

    2013-06-01

    The interactions between sponges and red macroalgae have been widely documented in tropical and subtropical environments worldwide, and many of them have been documented as mutualistic associations. Sponges, however, have also been frequently described as part of the associated fauna of rhodolith habitats (aggregations of free-living non-geniculated coralline macroalgae). Nonetheless, the types of interaction they establish as well as the role of sponges in these habitats remain unknown. In this study, the associations between sponges and rhodoliths were investigated in an estuarine ecosystem of the Mexican Pacific based on qualitative and quantitative data. A total of 13 sponge species were identified in five newly discovered rhodolith beds dominated by the non-geniculate coralline macroalga Lithophyllum margaritae. The sponge assemblages were strongly restricted to rhodolith habitats. The best predictor of sponge abundance (from 5.1 to 51.7 ind m-2) and species richness (from 2.6 to 6.1 sponge species m-2) was the rhodolith density rather than other population descriptors assessed (e.g., average size, branch density and sphericity). The identified sponges included a variety of forms: massive (46 %), encrusting (23 %), excavating (15 %), cushion-shape (8 %) and digitate (8 %). Moreover, more than 50 % of sponge species recorded (mainly massive and encrusting forms) were frequently found overgrowing and binding rhodoliths. Halichondria cf. semitubulosa and Mycale cecilia were the most common binding agents; these species bind an average of 3.1 and 6.6 rhodoliths per sponge individual, respectively. These findings reveal the importance of rhodoliths as habitat forming species, since these seaweed beds notably increased the substrate complexity in soft bottom environments. In addition, the relatively high abundance of sponges and their capability to bind rhodoliths suggest that these associated organisms could have an important contribution to rhodolith bed stability.

  19. Modeling fecal coliform contamination in a tidal Danshuei River estuarine system.

    PubMed

    Liu, Wen-Cheng; Chan, Wen-Ting; Young, Chih-Chieh

    2015-01-01

    A three-dimensional fecal coliform transport model was developed and incorporated into a hydrodynamic model to obtain a better understanding of local microbiological water quality in the tidal Danshuei River estuarine system of northern Taiwan. The model was firstly validated with the salinity and fecal coliform data measured in 2010. The concentration comparison showed quantitatively good agreement between the simulation and measurement results. Further, the model was applied to investigate the effects of upstream freshwater discharge variation and fecal coliform loading reduction on the contamination distributions in the tidal estuarine system. The qualitative and quantitative analyses clearly revealed that low freshwater discharge resulted in higher fecal coliform concentration. The fecal coliform loading reduction considerably decreased the contamination along the Danshuei River-Tahan Stream, the Hsintien Stream, and the Keelung River. PMID:25302451

  20. Carbon and nitrogen isotope ratios of juvenile winter flounder as indicators of inputs to estuarine systems.

    PubMed

    Pruell, Richard J; Taplin, Bryan K

    2015-12-30

    Stable carbon and nitrogen isotope ratios were measured in young-of-the-year (YOY) winter flounder, Pseudopleuronectes americanus, collected from several Rhode Island, USA estuarine systems. These included three coastal lagoons, an estuarine river and Narragansett Bay. The δ(13)C trends observed along transects in several systems showed isotopically depleted terrestrial signals in the upper reaches of the estuaries. Significant differences (P<0.05) in δ(15)N were observed among all estuarine systems and these differences correlated (P<0.01) with human population densities in the watersheds. Although Narragansett Bay has a strong north-south gradient in nutrient concentrations this trend was not reflected in flounder δ(15)N. The northernmost station with the highest nutrient concentrations unexpectedly had significantly lower δ(15)N values. Depleted δ(15)N values at this nutrient-rich station may indicate that concentration-dependent fractionation needs to be considered when using nitrogen isotope ratios in biota to monitor anthropogenic nitrogen inputs in systems with high nitrogen loadings. PMID:26541984

  1. Shoreline Erosion in the Albemarle-Pamlico Estuarine System, Northeastern North Carolina

    NASA Astrophysics Data System (ADS)

    Murphy, M. A.; Riggs, S. R.

    2002-12-01

    Computer analysis of aerial photographic series demonstrates that the estuarine shorelines within the North Carolina Albemarle-Pamlico coastal system are eroding at 2-3 times greater rates than previous studies reported. Specific rates and amounts of shoreline recession vary tremendously depending upon local variables including: 1) shoreline type, geometry, and composition; 2) geographic location, size, and shape of associated estuary; 3) frequency, intensity, and fetch of storms; 4) type and abundance of associated vegetation; and locally 5) boat wakes. Organic or wetland shorelines (marsh and swamp forest) comprise approximately 62% of the estuarine margins in NE NC, whereas sediment banks (low, high, and bluff) constitute about 38%. The goals of this study were to determine the rates of recession for different shoreline types and the role of local variables in the erosion process. Shorelines were mapped using high precision GPS mapping techniques, digital orthographic quarter quadrangles, and other georeferenced aerial photographs from the early 1950's to 2001. Shoreline change was then calculated for 20 estuarine study sites. Field mapping of each site provided data on shoreline characteristics and erosional processes. Data synthesis suggests mean annual shoreline erosion rates are significantly different for shoreline types as follows: 1) marshes = 7.4 ft/yr (range 2.7-17.0 ft/yr), low sediment banks = 5.0 ft/yr (range 1.0-12.0 ft/yr), bluff sediment banks = 5.0 ft/yr (range = 3.9-6.0 ft/yr), swamp forests = 3.0 ft/yr (range = 1.7-4.0 ft/yr), high sediment banks = 2.8 ft/yr (range = 2.7-2.9 ft/yr). Modified shorelines continue to erode, however at lower mean annual rates that range from 0.9-2.7 ft/yr. Locally, specific marsh shorelines have eroded at rates up to 100 ft/yr during particularly stormy periods. Thus, about 1166 acres of land are lost each year along the 1593 miles of mapped estuarine shoreline in NE NC. If these erosion rates are representative of

  2. Suspended matter and bottom deposits in the maroni estuarine system (French Guiana)

    NASA Astrophysics Data System (ADS)

    Jounneau, J. M.; Pujos, M.

    The purpose of the research on the major rivers in French Guiana is identification and estimation of their contribution to estuarine and inshore continental shelf sedimentation. Results are reported of field studies on the Maroni river conducted during one rainy season and one dry season. The sands of the Maroni fluvio-estuarine system are subject to seasonal variations. During the dry season the sands were distributed in two groups on either side of the lle aux Pigeons, whereas during the rainy season, greater homogeneity was noted throughout the estuary. The sands gave evidence of a lengthy history including marine, continental and finally fluviatile stages. The play a part in sedimentation on the inner continental shelf. Fine sediments had uniform characteristics throughout the year. Mineralogic and elemental composition in the vicinity of Ile Portal indicated that they were different on either side of a limit separating the fluviatile and estuarine zones. Sediment groups were respectively autochtonal (upstream) and allochtonal (downstream), while the characteristics of the clay assemblage and elemental composition in the latter zone are evidence of an Amazon river origin. Their patterns showed evidence of a local stock that is quickly diluted by the mass of sediments derived from the Amazon river, the predominant source for the region.

  3. DEVELOPMENT OF A CARCINOGEN ASSAY SYSTEM UTILIZING ESTUARINE FISHES

    EPA Science Inventory

    The objective of this project was the development of systems to assay the effects of chemical carcinogens on marine teleosts. It was determined that the LC-50 for benzidine with respect to Cyprinodon variegatus was ca. 64 ppm. Weekly contaminations of 1 ppm benzidine caused some ...

  4. ESTUARINE HAZARD ASSESSMENT IN THE PENSACOLA BAY SYSTEM

    EPA Science Inventory

    ersonnel from the Gulf Ecology Division have conducted a multiyear evaluation of the environmental condition of areas in the Pensacola Bay System affected by point and nonpoint contamination. Areas of study included coastal rivers, residential canals, bayous and bays impacted by ...

  5. Human impacts on morphodynamic thresholds in estuarine systems

    NASA Astrophysics Data System (ADS)

    Wang, Z. B.; Van Maren, D. S.; Ding, P. X.; Yang, S. L.; Van Prooijen, B. C.; De Vet, P. L. M.; Winterwerp, J. C.; De Vriend, H. J.; Stive, M. J. F.; He, Q.

    2015-12-01

    Many estuaries worldwide are modified, primarily driven by economic gain or safety. These works, combined with global climate changes heavily influence the morphologic development of estuaries. In this paper, we analyze the impact of human activities on the morphodynamic developments of the Scheldt Estuary and the Wadden Sea basins in the Netherlands and the Yangtze Estuary in China at various spatial scales, and identify mechanisms responsible for their change. Human activities in these systems include engineering works and dredging activities for improving and maintaining the navigation channels, engineering works for flood protection, and shoreline management activities such as land reclamations. The Yangtze Estuary is influenced by human activities in the upstream river basin as well, especially through the construction of many dams. The tidal basins in the Netherlands are also influenced by human activities along the adjacent coasts. Furthermore, all these systems are influenced by global changes through (accelerated) sea-level rise and changing weather patterns. We show that the cumulative impacts of these human activities and global changes may lead to exceeding thresholds beyond which the morphology of the tidal basins significantly changes, and loses its natural characteristics. A threshold is called tipping point when the changes are even irreversible. Knowledge on such thresholds or tipping points is important for the sustainable management of these systems. We have identified and quantified various examples of such thresholds and/or tipping points for the morphodynamic developments at various spatial and temporal scales. At the largest scale (mega-scale) we consider the sediment budget of a tidal basin as a whole. A smaller scale (macro-scale) is the development of channel structures in an estuary, especially the development of two competing channels. At the smallest scale (meso-scale) we analyze the developments of tidal flats and the connecting

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

    USGS Publications Warehouse

    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).

  7. Modelling of cohesive sediment dynamics in tidal estuarine systems: Case study of Tagus estuary, Portugal

    NASA Astrophysics Data System (ADS)

    Franz, G.; Pinto, L.; Ascione, I.; Mateus, M.; Fernandes, R.; Leitão, P.; Neves, R.

    2014-12-01

    Cohesive sediment dynamics in estuarine systems is a major issue in water quality and engineering problems. Numerical models can help to assess the complex dynamics of cohesive sediments, integrating the information collected in monitoring studies. Following a numerical approach we investigated the main factors that influence the cohesive sediment dynamics in an estuarine system composed of large mudflats (Tagus estuary, Portugal). After a spin up period of the bottom layer and considering the combined effect of waves and currents on the bottom shear stress, the dynamics of cohesive sediment during the fortnightly and daily erosion-sedimentation cycle was properly reproduced by the model. The results of cohesive suspended sediments were validated with data from sixteen monitoring stations located along the estuary and turbidity data measured by two multiparametric probes. The hydrodynamics were previously validated by harmonic analysis and with ADCP data. Although tidal currents are the major cause of cohesive sediment erosion, the results suggest that wind waves also play an important role. The simulated sediment mass involved in the fortnightly tidal cycle was in the same order of magnitude of the annual load from the rivers, as observed in previous studies based on field data.

  8. Habitat and hydrology: assessing biological resources of the Suwannee River Estuarine System

    USGS Publications Warehouse

    Raabe, Ellen A.; Edwards, Randy E.; McIvor, Carole C.; Grubbs, Jack W.; Dennis, George D.

    2007-01-01

    The U.S. Geological Survey conducted a pilot integrated-science study during 2002 and 2003 to map, describe, and evaluate benthic and emergent habitats in the Suwannee River Estuary on the Gulf Coast of Florida. Categories of aquatic, emergent, and terrestrial habitats were determined from hyperspectral imagery and integrated with hydrologic data to identify estuarine fish habitats. Maps of intertidal and benthic habitat were derived from 12-band, 4-m resolution hyperspectral imagery acquired in September 2002. Hydrologic data were collected from tidal creeks during the winter of 2002-03 and the summer-fall of 2003. Fish were sampled from tidal creeks during March 2003 using rivulet nets, throw traps, and seine nets. Habitat characteristics, hydrologic data, and fish assemblages were compared for tidal creeks north and south of the Suwannee River. Tidal creeks north of the river had more shoreline edge and shallow habitat than creeks to the south. Tidal creeks south of the river were generally of lower salinity (fresher) and supported more freshwater marsh and submerged aquatic vegetation. The southern creeks tended to be deeper but less sinuous than the northern creeks. Water quality and inundation were evaluated with hydrologic monitoring in the creeks. In-situ gauges, recording pressure and temperature, documented a net discharge of brackish to saline groundwater into the tidal creeks with pronounced flow during low tide. Groundwater flow into the creeks was most prominent north of the river. Combined fish-sampling results showed an overall greater abundance of organisms and greater species richness in the southern creeks, nominally attributed a greater range in water quality. Fish samples were dominated by juvenile spot, grass shrimp, bay anchovy, and silverside. The short time frame for hydrologic monitoring and the one-time fish-sampling effort were insufficient for forming definitive conclusions. However, the combination of hyperspectral imagery and

  9. Linking DNRA community structure and activity in a shallow lagoonal estuarine system

    PubMed Central

    Song, Bongkeun; Lisa, Jessica A.; Tobias, Craig R.

    2014-01-01

    Dissimilatory nitrate reduction to ammonium (DNRA) and denitrification are two nitrate respiration pathways in the microbial nitrogen cycle. Diversity and abundance of denitrifying bacteria have been extensively examined in various ecosystems. However, studies on DNRA bacterial diversity are limited, and the linkage between the structure and activity of DNRA communities has yet to be discovered. We examined the composition, diversity, abundance, and activities of DNRA communities at five sites along a salinity gradient in the New River Estuary, North Carolina, USA, a shallow temporal/lagoonal estuarine system. Sediment slurry incubation experiments with 15N-nitrate were conducted to measure potential DNRA rates, while the abundance of DNRA communities was calculated using quantitative PCR of nrfA genes encoding cytochrome C nitrite reductase, commonly found in DNRA bacteria. A pyrosequencing method targeting nrfA genes was developed using an Ion Torrent sequencer to examine the diversity and composition of DNRA communities within the estuarine sediment community. We found higher levels of nrfA gene abundance and DNRA activities in sediments with higher percent organic content. Pyrosequencing analysis of nrfA genes revealed spatial variation of DNRA communities along the salinity gradient of the New River Estuary. Percent abundance of dominant populations was found to have significant influence on overall activities of DNRA communities. Abundance of dominant DNRA bacteria and organic carbon availability are important regulators of DNRA activities in the eutrophic New River Estuary. PMID:25232351

  10. Impact of freshwater inflow on bacterial abundance and activity in the estuarine system Ria de Aveiro

    NASA Astrophysics Data System (ADS)

    Santos, Luísa; Vaz, Leandro; Marcial Gomes, Newton C.; Vaz, Nuno; Dias, João Miguel; Cunha, Ângela; Almeida, Adelaide

    2014-02-01

    The influence of freshwater flow on bacterial communities in the estuarine system Ria de Aveiro (Portugal) was investigated at two sites differently impacted by river inputs, representative of the marine and brackish water zones of the estuary. Sampling events were clustered based on hydrological features. The hydrodynamic was simulated with a Lagrangian model and related to microbiological parameters. Estuarine bacteria responded to different freshwater regimes developing distinct patterns of abundance and activity at the marine and brackish water zones. A circulation pattern induced by high river inflow produced vertical stratification in the marine zone, promoting a seaward flux of bacterioplankton, and stimulating the import of riverine phytoplankton and particle-attached bacteria to the brackish water zone. Advective transport and resuspension processes contributed to a 3-times increase in abundance of particle-attached bacteria during intense freshwater inputs. Additionally, bacterial activity in the estuary was controlled by inorganic nitrogen, responding to different freshwater inputs, which, in association with different prevailing sources of organic substrates induced significant changes in bacterial production. The dynamic and main controlling factors of bacterial communities are clearly impacted by freshwater inputs. Therefore, significant changes in the recycling of nutrients by microbial activities can be expected from alterations in freshwater inputs either related to global climate change or regional hydrological regimes.

  11. Blue carbon in human-dominated estuarine and shallow coastal systems.

    PubMed

    Kuwae, Tomohiro; Kanda, Jota; Kubo, Atsushi; Nakajima, Fumiyuki; Ogawa, Hiroshi; Sohma, Akio; Suzumura, Masahiro

    2016-04-01

    Estuarine and shallow coastal systems (ESCS) are recognized as not only significant organic carbon reservoirs but also emitters of CO2 to the atmosphere through air-sea CO2 gas exchange, thus posing a dilemma on ESCS's role in climate change mitigation measures. However, some studies have shown that coastal waters take up atmospheric CO2 (Catm), although the magnitude and determinants remain unclear. We argue that the phenomenon of net uptake of Catm by ESCS is not unusual under a given set of terrestrial inputs and geophysical conditions. We assessed the key properties of systems that show the net Catm uptake and found that they are often characteristic of human-dominated systems: (1) input of high terrestrial nutrients, (2) input of treated wastewater in which labile carbon is highly removed, and (3) presence of hypoxia. We propose that human-dominated ESCS are worthy of investigation as a contributor to climate change mitigation. PMID:26531815

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

    PubMed

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

    2016-05-01

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

  13. Nitrogen Isotope Ratios of Juvenile Winter Flounder as an Indicator of Anthropogenic Nitrogen Inputs to Estuarine Systems

    EPA Science Inventory

    Nitrogen isotope ratios (15N) were measured in muscle tissue of juvenile winter flounder, Pseudopleuronectes americanus, collected from several estuarine systems (lagoons, river, bay) along the coast of Rhode Island, USA over a three-year period. Significant differences i...

  14. Literature assessment of the Charlotte Harbor estuarine system and surrounding area, Southwest Florida

    USGS Publications Warehouse

    Stoker, Yvonne E.; Karavitis, George A.

    1983-01-01

    The Governor of Florida established the Charlotte Harbor Resource Planning and Management committee to recommend the course of action Florida should take in planning for potential growth in the rapidly growing area surrounding Charlotte Harbor. In May 1981, the U.S. Geological Survey began a planning study to determine detailed hydrologic study needs of the Charlotte Harbor area. A literature search of available data and reports pertaining to the Charlotte Harbor estuarine system and surrounding area resulted in almost 1,300 references. This report contains all references collected during this search. Some of the major reference topics are altered freshwater flow, water quality of the harbor and drainage systems, circulation and tides, coastal and marine resources, fisheries, geology and hydrology of the area, impact studies, water resources, flora and fauna of the area, and water supply. Sixty-eight key words or subject identifiers are used to the index report. (USGS)

  15. Impact of a major cyclone on a southeast African estuarine lake system

    NASA Astrophysics Data System (ADS)

    Forbes, A. T.; Cyrus, D. P.

    The St Lucia lake and estuarine system in northern Natal, South Africa was struck by Cyclone Domoina on 31 January 1984. This is the only cyclone known to have traversed part of South Africa. The ensuing flood levels in the St Lucia system (which have been exceeded perhaps only one other time in recorded history) provided an opportunity to assess the effect of a major disturbance on a subtropical estuarine system. Major geomorphological changes occurred in the mouth area where all man-made structures were obliterated. The two river channels were scoured from 2-3 m to 10-14 m in depth and widened by up to 300 m, while the shoreline between the two channels retreated in places up to 100 m. An estimated 16∗10 6 m 3 of sediment were removed from the lower reaches of the system including areas of mangrove and Phragmites australis swamp. One-metre tall mangrove saplings died following inundation lasting days to weeks. Effects on the fauna included redistribution of the tanaid Apseudes digitalis, the mysid Mesopodopsis africana, the copepod Pseudodiaptomus stuhlmanni, the polychaete Scololepis squamata and the bivalve Solen cylindraceus, all typical lake species which appeared in the tidal channel linking the lake with the sea. Responses of other species such as the penaeid prawns, the crab Scylla serrata and the sole Solea bleekeri suggested that physiological tolerance, extended larval or juvenile recruitment periods and prey switching minimized long-term flood effects. No large-scale mortalities were noted, and the absence of a temperature shock is considered to be a significant feature.

  16. A General Solution for Groundwater Flow in Estuarine Leaky Aquifer System with Considering Aquifer Anisotropy

    NASA Astrophysics Data System (ADS)

    Chen, Po-Chia; Chuang, Mo-Hsiung; Tan, Yih-Chi

    2014-05-01

    In recent years the urban and industrial developments near the coastal area are rapid and therefore the associated population grows dramatically. More and more water demand for human activities, agriculture irrigation, and aquaculture relies on heavy pumping in coastal area. The decline of groundwater table may result in the problems of seawater intrusion and/or land subsidence. Since the 1950s, numerous studies focused on the effect of tidal fluctuation on the groundwater flow in the coastal area. Many studies concentrated on the developments of one-dimensional (1D) and two-dimensional (2D) analytical solutions describing the tide-induced head fluctuations. For example, Jacob (1950) derived an analytical solution of 1D groundwater flow in a confined aquifer with a boundary condition subject to sinusoidal oscillation. Jiao and Tang (1999) derived a 1D analytical solution of a leaky confined aquifer by considered a constant groundwater head in the overlying unconfined aquifer. Jeng et al. (2002) studied the tidal propagation in a coupled unconfined and confined costal aquifer system. Sun (1997) presented a 2D solution for groundwater response to tidal loading in an estuary. Tang and Jiao (2001) derived a 2D analytical solution in a leaky confined aquifer system near open tidal water. This study aims at developing a general analytical solution describing the head fluctuations in a 2D estuarine aquifer system consisted of an unconfined aquifer, a confined aquifer, and an aquitard between them. Both the confined and unconfined aquifers are considered to be anisotropic. The predicted head fluctuations from this solution will compare with the simulation results from the MODFLOW program. In addition, the solutions mentioned above will be shown to be special cases of the present solution. Some hypothetical cases regarding the head fluctuation in costal aquifers will be made to investigate the dynamic effects of water table fluctuation, hydrogeological conditions, and

  17. THE PACIFIC COAST ESTUARINE INFORMATION SYSTEM: CREATING A BASELINE FOR THE FUTURE

    EPA Science Inventory

    Coastal researchers and managers have a growing need for ready access to a diversity of
    data types, including estuarine-specific lists of native and nonindigenous species and estuarine/landscape characteristics. These data are key components in ecological risk assessments in g...

  18. Tidal regime and morphodynamic changes in estuarine systems as a function of sea-level rise

    NASA Astrophysics Data System (ADS)

    Mallinson, D. J.; Culver, S. J.; Mulligan, R.; Leorri, E.; Mitra, S.; Riggs, S. R.; Moran, K.

    2011-12-01

    Tidal amplitude and currents along coastlines will change in conjunction with sea-level rise, when certain geomorphic and bathymetric conditions are met. Under conditions of decreasing protection from barrier islands, associated with increased inlet activity or overstepping of islands, tidal amplitude can rapidly increase in estuaries and along mainland coastlines and significantly amplify the effects of a minor sea-level rise. Impacts to coastal systems may be economically and environmentally significant. Additionally, sea-level curves developed from areas where tidal regime change has occurred in the past must be evaluated carefully for the effects of tidal amplitude. The impacts of tidal amplitude changes in response to sea-level rise have been noted in the Minas Basin, Delaware Bay, and, in this study, the Albemarle-Pamlico Estuarine System of North Carolina. Our group is investigating the magnitude of changes in response to variations in geomorphic and bathymetric conditions, and past climate events. Methods include the use of seismic data, sedimentology, microfossil analysis, oxygen isotopes, Mg/Ca, black carbon, and radiocarbon ages to reconstruct paleobathymetry, paleoenvironments and paleoclimate conditions during the late Holocene. Paleobathymetric/paleogeomorphic models are being derived to enable hydrodynamic modeling using Delft3D software. Initial runs for the Pamlico Sound have been performed to reconstruct hydrodynamic conditions during a barrier break-down event associated with the Medieval Climate Anomaly (ca. 1000 cal yr BP). Likewise, models are being used to understand hydrodynamics in the Currituck Sound (a smaller lagoon in northeastern NC) in response to historical inlet activity. Results illustrate the potential for an eight-fold increase in tidal amplitude, with significant variations within the estuarine system, and large increases in tidal currents well into the estuaries, resulting in significant changes to salinity structures and

  19. Seasonal distribution of aliphatic hydrocarbons in the Vaza Barris Estuarine System, Sergipe, Brazil.

    PubMed

    Barbosa, José Carlos S; Santos, Lukas G G V; Sant'Anna, Mércia V S; Souza, Michel R R; Damasceno, Flaviana C; Alexandre, Marcelo R

    2016-03-15

    The seasonal assessment of anthropogenic activities in the Vaza Barris estuarine river system, located in the Sergipe state, northeastern Brazil, was performed using the aliphatic hydrocarbon distribution. The aliphatic hydrocarbon and isoprenoid (Pristane and Phytane) concentrations ranged between 0.19μgg(-1) and 8.5μgg(-1) of dry weight. Data were analyzed using Kruskal-Wallis test, with significance level set at p<0.05, and no seasonality distribution change was observed. The Carbon Preference Index (CPI), associated with n-alkanes/n-C16, Low Molecular Weight/High Molecular Weight ratio (LMW/HMW) and Terrigenous to Aquatic Ratio (TAR) suggested biogenic input of aliphatic hydrocarbons for most samples, with significant contribution of higher plants. PMID:26837270

  20. Late Quaternary in a South Atlantic estuarine system: Stratigraphic and paleontologic indicators of coastal evolution

    NASA Astrophysics Data System (ADS)

    Aliotta, Salvador; Ginsberg, Silvia S.; Spagnuolo, Jorge O.; Farinati, Ester; Giagante, Darío; Vecchi, Laura G.

    2013-08-01

    The decisive influence of Late Quaternary sea level changes on the geological evolution of the coastal plain and adjacent continental shelf around the world has long been recognized. Coastal environments evolve actively during transgressive-regressive cycles whose development depends on sea level and sediment supply variations. The interaction of these variables was key to the current morphological and sedimentological configuration of coastal regions. Particularly, the estuarine system of Bahía Blanca (Argentina) presents various types of deposits and marine fossil accumulations, such as paleochannels in the subbottom, sand-shell ridges and extensive layers with fossils in life position. These features are important geological indicators, because its analysis allows us to define different paleoenvironmental conditions that prevailed during the coastal evolutionary process.

  1. 15 CFR 921.51 - Estuarine research guidelines.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... MANAGEMENT NATIONAL ESTUARINE RESEARCH RESERVE SYSTEM REGULATIONS Special Research Projects § 921.51 Estuarine research guidelines. (a) Research within the National Estuarine Research Reserve System shall be... 15 Commerce and Foreign Trade 3 2013-01-01 2013-01-01 false Estuarine research guidelines....

  2. 15 CFR 921.51 - Estuarine research guidelines.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... MANAGEMENT NATIONAL ESTUARINE RESEARCH RESERVE SYSTEM REGULATIONS Special Research Projects § 921.51 Estuarine research guidelines. (a) Research within the National Estuarine Research Reserve System shall be... 15 Commerce and Foreign Trade 3 2014-01-01 2014-01-01 false Estuarine research guidelines....

  3. 15 CFR 921.51 - Estuarine research guidelines.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... MANAGEMENT NATIONAL ESTUARINE RESEARCH RESERVE SYSTEM REGULATIONS Special Research Projects § 921.51 Estuarine research guidelines. (a) Research within the National Estuarine Research Reserve System shall be... 15 Commerce and Foreign Trade 3 2010-01-01 2010-01-01 false Estuarine research guidelines....

  4. 15 CFR 921.51 - Estuarine research guidelines.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... MANAGEMENT NATIONAL ESTUARINE RESEARCH RESERVE SYSTEM REGULATIONS Special Research Projects § 921.51 Estuarine research guidelines. (a) Research within the National Estuarine Research Reserve System shall be... 15 Commerce and Foreign Trade 3 2011-01-01 2011-01-01 false Estuarine research guidelines....

  5. 15 CFR 921.51 - Estuarine research guidelines.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... MANAGEMENT NATIONAL ESTUARINE RESEARCH RESERVE SYSTEM REGULATIONS Special Research Projects § 921.51 Estuarine research guidelines. (a) Research within the National Estuarine Research Reserve System shall be... 15 Commerce and Foreign Trade 3 2012-01-01 2012-01-01 false Estuarine research guidelines....

  6. Estuarine Food for Thought

    NASA Astrophysics Data System (ADS)

    M�ller-Solger, A. B.; M�ller-Navarra, D. B.

    2002-12-01

    Recent research in animal and human nutrition has shown the importance of long-chain polyunsaturated fatty acids (LC-PUFA) such as the n-3 LC-PUFA eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These LC-PUFA are needed for healthy development and functioning of the nervous and vascular systems. De novo synthesis or elongation to LC-PUFA in animals is inefficient at best; thus sufficient amounts of these PUFA must be supplied by food sources. Algae, especially diatoms, dinoflagellates, and cryptophytes, are the quantitatively most important producers of EPA and DHA. These types of algae often dominate estuarine producer communities. The upper San Francisco Estuary is no exception, and we found its LC-PUFA-rich phytoplankton biomass, but not the quantitatively prevalent terrestrial plant detritus, to be highly predictive of zooplankton (Daphnia) growth. In contrast, in freshwater lakes dominated by relatively LC-PUFA-poor phytoplankton, EPA, not total phytoplankton biomass, best predicted Daphnia growth. The commonly high abundance of LC-PUFA-rich algae in estuaries may help explain the high trophic efficiencies in these systems and resulting high consumer production. Moreover, LC-PUFA-rich estuarine food resources may also provide essential nutrition and associated health and evolutionary benefits to land-dwelling consumers of such foods, including humans. Ensuring LC-PUFA-rich, uncontaminated estuarine production is thus an important goal for estuarine restoration and a convincing argument for estuarine conservation.

  7. Spatio-temporal distribution, source, and genotoxic potential of polycyclic aromatic hydrocarbons in estuarine and riverine sediments from southern India.

    PubMed

    Goswami, Prasun; Ohura, Takeshi; Guruge, Keerthi S; Yoshioka, Miyako; Yamanaka, Noriko; Akiba, Masato; Munuswamy, Natesan

    2016-08-01

    In order to categorize the distribution, source, and effects of polycyclic aromatic hydrocarbons (PAHs) in aquatic systems of southern India, chemical and toxicological analyses were performed on surface and core sediments, collected from Adyar river, Cooum river, Ennore estuary, and Pulicat lake near Chennai city. The total PAH concentration in surface sediment ranged from 13 to 31,425ng/g with a mean value of 4320ng/g; the concentration was markedly higher in Cooum river compared to that at other sites. The historical PAH dissemination in core samples in the Cooum river, Ennore estuary, and Pulicat lake ranged from 30 to 31,425ng/g, from 8.6 to 910ng/g, and from 62 to 546ng/g, respectively. Surface sediments were predominantly contaminated with low molecular weight (LMW) PAHs. Historical profiles suggest that PAH contamination in the area is now greater than it had been in the past. PAH accumulation in Pulicat lake was distinct from that at other locations where high molecular weight (HMW) PAHs were predominant. DNA damage in HepG2 cells treated with sediment extracts from different locations showed a good correlation with their respective total PAH levels. Statistical analysis revealed that 3-ring and 4-ring PAHs may synergistically contribute to the genotoxic potency compared to others in sediments. The study also showed that a majority of PAHs in the study area indicated a petrogenic origin. Based on the enrichment and toxicological assessment of PAHs in sediments, Cooum river was shown to suffer the highest biological impairment among the studied water bodies. PMID:27092974

  8. Tracing coastal and estuarine groundwater discharge sources in a complex faulted and fractured karst aquifer system

    NASA Astrophysics Data System (ADS)

    Lagomasino, D.; Price, R. M.

    2013-05-01

    Groundwater discharge can be an important input of water, nutrients and other constituents to coastal wetlands and adjacent marine areas, particularly in karst regions with little to no surface water flow. A combination of natural processes (e.g., sea-level rise and climate change) and anthropogenic pressures (e.g., urban growth and development) can alter the subterranean water flow to the coastline. For water management practices and environmental preservation to be better suited for the natural and human environment, a better understanding is needed of the hydrogeologic connectivity between the areas of fresh groundwater recharge and the coastal zone. The Yucatan peninsula has a unique tectonic and geologic history consisting of a Cretaceous impact crater, Miocene and Eocene tectonic plate movements, and multiple sea-level stands. These events have shaped many complex geologic formations and structures. The Sian Káan Biosphere Reserve (SKBR), a UNESCO World Heritage Site located along the Atlantic Ocean, overlaps two distinct hydrogeologic regions: the evaporate region to the south and south west, and the Holbox Fracture Zone to the north. These two regions create a complex network of layered, perched and fractured aquifers and an extensive groundwater cave network. The two regions are distinguished by bedrock mineralogical differences that can be used to trace shallow subsurface water from interior portions of the peninsula to the Bahia de la Ascension in the SKBR. The objective of this research was to use naturally occurring geochemical tracers (eg., Cl-, SO42-, HCO3-, K+, Mg2+, Na+, Ca2+ and stable isotopes of oxygen and hydrogen) to decipher the sources of groundwater flow through the coastal wetlands of the SKBR and into the Bahia de la Ascension. Surface water and groundwater samples were collected during two field campaigns in 2010 and 2012 within the coastal and estuarine waters of the SKBR. Additional water samples were collected at select cenotes along

  9. Nutrient fluctuations in the Quatipuru river: A macrotidal estuarine mangrove system in the Brazilian Amazonian basin

    NASA Astrophysics Data System (ADS)

    Pamplona, Fábio Campos; Paes, Eduardo Tavares; Nepomuceno, Aguinaldo

    2013-11-01

    The temporal and spatial variability of dissolved inorganic nutrients (NO3-, NO2-, NH4+, PO43- and DSi), total nitrogen (TN), total phosphorus (TP), nutrient ratios, suspended particulate matter (SPM) and Chlorophyll-a (Chl-a) were evaluated for the macrotidal estuarine mangrove system of the Quatipuru river (QUATIES), east Amazon coast, North Brazil. Temporal variability was assessed by fortnightly sampling at a fixed station within the middle portion of the estuary, from November 2009 to November 2010. Spatial variability was investigated from two field surveys conducted in November 2009 (dry season) and May 2010 (rainy season), along the salinity gradient of the system. The average DIN (NO3- + NO2- + NH4+) concentration of 9 μM in the dry season was approximately threefold greater in comparison to the rainy season. NH4+ was the main form of DIN in the dry season, while NO3- predominated in the rainy season. The NH4+ concentrations in the water column during the dry season are largely attributed to release by tidal wash-out of the anoxic interstitial waters of the surficial mangrove sediments. On the other hand, the higher NO3- levels during the wet season, suggested that both freshwater inputs and nitrification processes in the water column acted in concert. The river PO43- concentrations (DIP < 1 μM) were low and similar throughout the year. DIN was thus responsible for the major temporal and spatial variability of the dissolved DIN:DIP (N:P) molar ratios and nitrogen corresponded, in general, to the prime limiting nutrient for the sustenance of phytoplankton biomass in the estuary. During the dry season, P-limitation was detected in the upper estuary. PO43- adsorption to SPM was detected during the rainy season and desorption during the dry season along the salinity gradient. In general, the average Chl-a level (14.8 μg L-1) was 2.5 times higher in the rainy season than in the dry season (5.9 μg L-1). On average levels reached maxima at about 14 km from

  10. Meiobenthos assemblages in the mekong estuarine system with special focus on free-living marine nematodes

    NASA Astrophysics Data System (ADS)

    Quang, Ngo Xuan; Vanreusel, Ann; Smol, Nic; Chau, Nguyen Ngoc

    2010-12-01

    Meiobenthos assemblages in eight estuaries of the Mekong river system were investigated in August 2008 (from the Cua Tieu estuary to the Tran De estuary). In each estuary, one sampling station was established for meiobenthos sampling. Twelve major taxa of meiobenthos were recorded in this estuarine system, including Nematoda, Copepoda, Turbellaria, Polychaeta, Oligochaeta, Tardigrada, Bivalvia, Ostracoda, Amphipoda, Cumacea, Gastrotricha, Gastropoda, and Crustacean Nauplii larvae. The densities of the meiobenthos range from 581 to 3168 inds/10 cm2. Nematodes always occupy the highest numbers with a percentage ranging from 64-99%. There are 135 nematode genera recorded in this study with the following as dominant genera Desmodora, Leptolaimus, Halalaimus, Thalassomonhystera, Theristus, Daptonema, Rhynchonema, Parodontophora, and Oncholaimus. Although the biodiversity of the meiobenthos at higher taxa level is not high compared to other marine environments, the estimates of nematode biodiversity at the genus level indicates high values. The increase in number of genera with increasing sampling intensity illustrate that the diversity is underestimated and would have been higher if the authors had considered a larger number of individuals, more replicates per station, and more sampling stations.

  11. Foraminiferal Distributions, Sedimentation Rates and Patterns in the Albemarle Estuarine System, North Carolina

    NASA Astrophysics Data System (ADS)

    Vance, D. J.; Corbett, D. R.; Culver, S. J.

    2002-12-01

    The modern distribution of benthic foraminifera of the Albemarle Estuarine System (AES) has been characterized by studying 50 strategically chosen sites to provide a model for paleoenvironmental interpretations of short sediment cores (15-75 cm). Water bodies studied within the AES include Albemarle Sound, Currituck Sound, Roanoke Sound, Croatan Sound, northern Pamlico Sound, North River, Pasquotank River, Alligator River, as well as Oregon Inlet and the adjacent foreshore and shoreface of the Atlantic Ocean. Sedimentation rates in the study area have been addressed using 210Pb and 137Cs dating methods. Five foraminiferal assemblages are present: an inner estuary biofacies characterized by two dominant genera, Ammobaculites and Ammotium, with moderate percentages of Miliammina fusca and minor percentages of Ammoastuta salsa; an outer estuary biofacies characterized again by Ammobaculites and Ammotium, but with lower percentages of Miliammina fusca; a marsh shoreline biofacies characterized by a mixed assemblage dominated by Ammobaculites and Ammotium with minor to moderate percentages of adjacent marsh foraminifera; a marsh biofacies characterized by varying abundances of Ammoastuta inepta, Arenoparella mexicana, Haplophragmoides wilberti, Jadammina macrescens, Miliammina earlandi, Miliammina fusca, Tiphotrocha comprimata, Trochammina inflata, as well as the genera Ammobaculites and Ammotium; and a marine (normal salinity) biofacies characterized mainly by Elphidium excavatum and minor percentages of other elphidiids. Sedimentation rates were studied from 28 short cores taken along transects in all the major water bodies. Rates were as high as 0.45 cm/yr at the head of Albemarle Sound and as little as 0.05 cm/yr 60 km away in the eastern part of the Albemarle. The embayed tributaries exhibited sedimentation rates on the order of 0.25 cm/yr. Limited information on sedimentation rates was provided by cores in eastern sounds, which had only a few centimeters of recent

  12. Evaluation of anthropogenic contamination using sterol markers in a tropical estuarine system of northeast Brazil.

    PubMed

    Frena, Morgana; Souza, Michel R R; Damasceno, Flaviana C; Madureira, Luiz A S; Alexandre, Marcelo R

    2016-08-15

    The São Francisco River estuarine system, located in the Northeast coast of Brazil, has great economic, tourist and social importance. Its waters are used for activities such as agriculture, aquaculture, navigation and fishery, which supplies the surrounding communities. In this study, sterols markers were determined in twenty-eight sediment samples from São Francisco River estuary by gas chromatography - mass spectrometry (GC-MS). Sterol analysis was useful to distinguish between anthropogenic and biogenic organic matter (OM) sources in the studied area. Six sterols were quantified, suggesting different sources. Concentrations of fecal sterol (coprostanol) were lower than 500ngg(-1), suggesting no indicative of severe sewage contamination.However, two stations showed concentrations around 100ngg(-1) and the values for the coprostanol/(coprostanol+cholestanol) and coprostanol/cholesterol ratios indicates sewage contamination. The results in this study may be considered as baseline concentrations to be used as future reference for monitoring programs to prevent anthropogenic impacts. PMID:27207024

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

    PubMed Central

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

    2014-01-01

    Community assembly theories such as species sorting theory provide a framework for understanding the structures and dynamics of local communities. The effect of theoretical mechanisms can vary with the scales of observation and effects of specific environmental factors. Based on 16S rRNA gene tag pyrosequencing, different structures and temporal succession patterns were discovered between the surface sediments and bottom water microbial communities in the Pearl River Estuary (PRE). The microbial communities in the surface sediment samples were more diverse than those in the bottom water samples, and several genera were specific for the water or sediment communities. Moreover, water temperature was identified as the main variable driving community dynamics and the microbial communities in the sediment showed a greater temporal change. We speculate that nutrient-based species sorting and bacterial plasticity to the temperature contribute to the variations observed between sediment and water communities in the PRE. This study provides a more comprehensive understanding of the microbial community structures in a highly dynamic estuarine system and sheds light on the applicability of ecological theoretical mechanisms. PMID:24732211

  14. Assessment of the climate change impacts on fecal coliform contamination in a tidal estuarine system.

    PubMed

    Liu, Wen-Cheng; Chan, Wen-Ting

    2015-12-01

    Climate change is one of the key factors affecting the future microbiological water quality in rivers and tidal estuaries. A coupled 3D hydrodynamic and fecal coliform transport model was developed and applied to the Danshuei River estuarine system for predicting the influences of climate change on microbiological water quality. The hydrodynamic and fecal coliform model was validated using observational salinity and fecal coliform distributions. According to the analyses of the statistical error, predictions of the salinity and the fecal coliform concentration from the model simulation quantitatively agreed with the observed data. The validated model was then applied to predict the fecal coliform contamination as a result of climate change, including the change of freshwater discharge and the sea level rise. We found that the reduction of freshwater discharge under climate change scenarios resulted in an increase in the fecal coliform concentration. The sea level rise would decrease fecal coliform distributions because both the water level and the water volume increased. A reduction in freshwater discharge has a negative impact on the fecal coliform concentration, whereas a rising sea level has a positive influence on the fecal coliform contamination. An appropriate strategy for the effective microbiological management in tidal estuaries is required to reveal the persistent trends of climate in the future. PMID:26545372

  15. Particle release transport in Danshuei River estuarine system and adjacent coastal ocean: a modeling assessment.

    PubMed

    Chen, Wei-Bo; Liu, Wen-Cheng; Kimura, Nobuaki; Hsu, Ming-Hsi

    2010-09-01

    A three-dimensional hydrodynamic model was created to study the Danshuei River estuarine system and adjacent coastal ocean in Taiwan. The model was verified using measurements of the time-series water surface elevation, tidal current, and salinity from 1999. We conclude that our model is consistent with these observations. Our particle-tracking model was also used to explore the transport of particles released from the Hsin-Hai Bridge, an area that is heavily polluted. The results suggest that it takes a much longer time for the estuary to be flushed out under low freshwater discharge conditions than with high freshwater discharge. We conclude that the northeast and southwest winds minimally impact particle dispersion in the estuary. The particles fail to settle to the bottom in the absence of density-induced circulation. Our model was also used to simulate the ocean outfall at the Bali. Our experimental results suggest that the tidal current dominates the particle trajectories and influences the transport properties in the absence of a wind stress condition. The particles tend to move northeast or southwest along the coast when northeast or southwest winds prevail. Our data suggest that wind-driven currents and tidal currents play important roles in water movement as linked with ocean outfall in the context of the Danshuei River. PMID:19680754

  16. Phytoplankton productivity and biomass in the Charlotte Harbor estuarine system, Florida

    USGS Publications Warehouse

    McPherson, Benjamin F.; Montgomery, Ralph T.; Emmons, Edward E.

    1990-01-01

    Phytoplankton carbon-14 productivity at a depth of 50 percent of surface light and chlorophyll-a concentrations were measured every other month from November 1985 through September 1986 at 12 stations in the Charlotte Harbor estuarine system. Maximum productivity and chlorophyll-a concentrations occurred during summer or early autumn near the months of tidal rivers. Most of the variability in light-normalized productivity and chlorophyll-a could be attributed to two factors derived from Principal Component Analysis of ambient water-quality characteristics. One factor related to seasonal variability and the other to spatial variability. The seasonal factor incorporated the interaction of temperature and nutrients. The spatial factor incorporated the interaction of salinity, nutrients, and water color that resulted from the mixing of freshwater inflow and seawater. Although freshwater inflow increased the availability of nutrients in low salinity (less than 10 %) waters, the highly colored freshwater restricted light penetration and phytoplankton productivity. Maximum productivity and biomass occurred where color associated with the freshwater inflow had been diluted by seawater so that light and nutrients were both available. Concentrations of inorganic nitrogen were often at or below detection limit throughout most of the high salinity (greater than 20 %) waters of the estuary and was probably the most critical nutrient in limiting phytoplankton productivity.

  17. Factors affecting the efficiency of carbon monoxide photoproduction in the St. Lawrence estuarine system (Canada).

    PubMed

    Zhang, Yong; Xie, Huixiang; Chen, Guohua

    2006-12-15

    This study examined the effects of water temperature and the origin (terrestrial vs marine) and light history of chromophoric dissolved organic matter (CDOM) on the apparent quantum yields of carbon monoxide (CO) photoproduction for water samples collected along a salinity gradient (salinity range: 0-33) in the St. Lawrence estuarine system (Canada). The solar insolation-weighted mean apparent quantum yield of CO (phico) decreased as much as fourfold with increasing salinity and showed a strong positive correlation with the dissolved organic carbon-specific absorption coefficient at 254 nm. This suggests that terrestrial CDOM is more efficient at photochemically producing CO than is marine algae-derived CDOM and that aromatic moieties are likely involved in this photoprocess. CDOM photobleaching, mainly at the very early stage, dramatically decreased phico (by up to 6.4 times) for low-salinity samples, but photobleaching had little effect on the most marine sample. For a 20 degree C increase in temperature, phico increased by approximately 70% for low-salinity samples and 30-40% for saline samples. This study demonstrates that water temperature, as well as the CDOM's origin and light history, strongly affect the efficiency of CO photoproduction. These factors should be taken into account in modeling the photochemical fluxes of CO and other related CDOM photoproducts on varying spatiotemporal scales. PMID:17256526

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

    PubMed

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

    2016-06-15

    Mercury (Hg) is considered a contaminant of global concern for coastal environments due to its toxicity, widespread occurrence in sediment, and bioaccumulation in tissue. Coastal New Jersey, USA, is characterized by shallow bays and wetlands that provide critical habitat for wildlife but share space with expanding urban landscapes. This study was designed as an assessment of the magnitude and distribution of Hg in coastal New Jersey sediments and critical species using publicly available data to highlight potential data gaps. Mercury concentrations in estuary sediments can exceed 2μg/g and correlate with concentrations of other metals. Based on existing data, the concentrations of Hg in mussels in southern New Jersey are comparable to those observed in other urbanized Atlantic Coast estuaries. Lack of methylmercury data for sediments, other media, and tissues are data gaps needing to be filled for a clearer understanding of the impacts of Hg inputs to the ecosystem. PMID:27158049

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

    USGS Publications Warehouse

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

    2016-01-01

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

  20. Distribution, sources and biogeochemistry of organic matter in a mangrove dominated estuarine system (Indian Sundarbans) during the pre-monsoon

    NASA Astrophysics Data System (ADS)

    Ray, R.; Rixen, T.; Baum, A.; Malik, A.; Gleixner, G.; Jana, T. K.

    2015-12-01

    The sources and distribution of dissolved organic carbon (DOC), particulate organic carbon (POC) and dissolved inorganic carbon (DIC) in the Indian Sundarbans mangrove and Hooghly estuarine system were examined during the pre-monsoon (summer) 2014. DOC is the dominant form of organic matter (OM) in the studied estuarine waters and represents a mixture of mangrove and riverine sources. Microbial degradation of land derived OM results in a high pCO2 in the Hooghly estuarine waters while enrichment in δ13C-DIC ascribes to CO2 uptake by phytoplankton in the Sundarbans water. Higher δ15N in the particulate organic nitrogen (PON) of the mangrove and marine zone could be associated with enhanced phytoplankton production sustained by nitrate from mangrove derived OM decomposition and/or nitrate imported from the Bay of Bengal. Low organic carbon contents and elemental ratios (TN/TOC) indicate an intense mineralization and transformation of OM in the sediments, resulting insignificantly different OM compositions compared to those of the three major sources: land derived OM, mangrove leaf litter (Avicennia marina) and in situ phytoplankton production.

  1. The structure of the benthic macrofaunal assemblages and sediments characteristics of the Paraguaçu estuarine system, NE, Brazil

    NASA Astrophysics Data System (ADS)

    Barros, Francisco; Hatje, Vanessa; Figueiredo, Maria Betânia; Magalhães, Wagner Ferreira; Dórea, Haroldo Silveira; Emídio, Elissandro Soares

    2008-07-01

    The structure of the benthic macrofaunal assemblages of the estuarine portion of Paraguaçu River, NE, Brazil, and its relationship with surface sediment characteristics (trace metals, PAHs, nutrients and grain size) and physical variables were investigated at ten stations on two contrasting occasions, summer (dry season) and winter (rainy season). A total of 1258 individuals (632 in winter and 626 in summer) and 62 taxa representing polychaetes, crustaceans, bivalves, echinoderms, bryozoans, sponges, cnidarians and cephalochordates were collected. Benthic assemblages in the upper estuary were unlike those in the lower estuary and a clear substitution of benthic taxa along the estuary was observed. Macrofaunal invertebrates in the low salinity region, composed of coarse sediments, were dominated by tellinids, venerids (bivalves), cirolanids (isopods), cyclopoids (copepods), and nereidids (polychaetes). While the high salinity region, composed of fine sediments, were dominated by nuculids (bivalves), cirratulids (polychaetes), and by amphiurids (ophiuroids). The Paraguaçu estuarine system is not severely affected by anthropogenic activities. In the great majority of the study sites, concentrations of trace metals and PAHs in the sediments were near background values. Nutrients values were also low. We formulated new models of taxon distribution and suggested detailed studies on the effects of salinity variation and studies using functional approaches to better understand the processes causing the spatial patterns in tropical estuarine benthic assemblages.

  2. COMPARISON OF MUTAGEN ACCUMULATION IN 3 ESTUARINE SPECIES USING THE SALMONELLA/MICROSOME ACTIVATION SYSTEM

    EPA Science Inventory

    Three estuarine organisms--oysters (Crassostrea virginica), sea squirts (Mogulla sp.), and shrimp (Peneaus sp.)--were examined for Ames test detectable levels of mutagens. Whole-tissue extracts of these organisms were made and tested using Salmonella typhimurium strains TA98, TA1...

  3. Using a Laboratory Simulator in the Teaching and Study of Chemical Processes in Estuarine Systems

    ERIC Educational Resources Information Center

    Garcia-Luque, E.; Ortega, T.; Forja, J. M.; Gomez-Parra, A.

    2004-01-01

    The teaching of Chemical Oceanography in the Faculty of Marine and Environmental Sciences of the University of Cadiz (Spain) has been improved since 1994 by the employment of a device for the laboratory simulation of estuarine mixing processes and the characterisation of the chemical behaviour of many substances that pass through an estuary. The…

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

    EPA Science Inventory

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

  5. Overview of integrative tools and methods in assessing ecological integrity in estuarine and coastal systems worldwide.

    PubMed

    Borja, Angel; Bricker, Suzanne B; Dauer, Daniel M; Demetriades, Nicolette T; Ferreira, João G; Forbes, Anthony T; Hutchings, Pat; Jia, Xiaoping; Kenchington, Richard; Carlos Marques, João; Zhu, Changbo

    2008-09-01

    In recent years, several sets of legislation worldwide (Oceans Act in USA, Australia or Canada; Water Framework Directive or Marine Strategy in Europe, National Water Act in South Africa, etc.) have been developed in order to address ecological quality or integrity, within estuarine and coastal systems. Most such legislation seeks to define quality in an integrative way, by using several biological elements, together with physico-chemical and pollution elements. Such an approach allows assessment of ecological status at the ecosystem level ('ecosystem approach' or 'holistic approach' methodologies), rather than at species level (e.g. mussel biomonitoring or Mussel Watch) or just at chemical level (i.e. quality objectives) alone. Increasing attention has been paid to the development of tools for different physico-chemical or biological (phytoplankton, zooplankton, benthos, algae, phanerogams, fishes) elements of the ecosystems. However, few methodologies integrate all the elements into a single evaluation of a water body. The need for such integrative tools to assess ecosystem quality is very important, both from a scientific and stakeholder point of view. Politicians and managers need information from simple and pragmatic, but scientifically sound methodologies, in order to show to society the evolution of a zone (estuary, coastal area, etc.), taking into account human pressures or recovery processes. These approaches include: (i) multidisciplinarity, inherent in the teams involved in their implementation; (ii) integration of biotic and abiotic factors; (iii) accurate and validated methods in determining ecological integrity; and (iv) adequate indicators to follow the evolution of the monitored ecosystems. While some countries increasingly use the establishment of marine parks to conserve marine biodiversity and ecological integrity, there is awareness (e.g. in Australia) that conservation and management of marine ecosystems cannot be restricted to Marine Protected

  6. Northeast Coastal Ocean Forecast System (NECOFS): A Multi-scale Global-Regional-Estuarine FVCOM Model

    NASA Astrophysics Data System (ADS)

    Beardsley, R. C.; Chen, C.

    2014-12-01

    The Northeast Coastal Ocean Forecast System (NECOFS) is a global-regional-estuarine integrated atmosphere/surface wave/ocean forecast model system designed for the northeast US coastal region covering a computational domain from central New Jersey to the eastern end of the Scotian Shelf. The present system includes 1) the mesoscale meteorological model WRF (Weather Research and Forecasting); 2) the regional-domain FVCOM covering the Gulf of Maine/Georges Bank/New England Shelf region (GOM-FVCOM); 3) the unstructured-grid surface wave model (FVCOM-SWAVE) modified from SWAN with the same domain as GOM-FVCOM; 3) the Mass coastal FVCOM with inclusion of inlets, estuaries and intertidal wetlands; and 4) three subdomain wave-current coupled inundation FVCOM systems in Scituate, MA, Hampton River, NH and Mass Bay, MA. GOM-FVCOM grid features unstructured triangular meshes with horizontal resolution of ~ 0.3-25 km and a hybrid terrain-following vertical coordinate with a total of 45 layers. The Mass coastal FVCOM grid is configured with triangular meshes with horizontal resolution up to ~10 m, and 10 layers in the vertical. Scituate, Hampton River and Mass Bay inundation model grids include both water and land with horizontal resolution up to ~5-10 m and 10 vertical layers. GOM-FVCOM is driven by surface forcing from WRF model output configured for the region (with 9-km resolution), the COARE3 bulk air-sea flux algorithm, local river discharges, and tidal forcing constructed by eight constituents and subtidal forcing on the boundary nested to the Global-FVCOM. SWAVE is driven by the same WRF wind field with wave forcing at the boundary nested to Wave Watch III configured for the northwestern Atlantic region. The Mass coastal FVCOM and three inundation models are connected with GOM-FVCOM through one-way nesting in the common boundary zones. The Mass coastal FVCOM is driven by the same surface forcing as GOM-FVCOM. The nesting boundary conditions for the inundation models

  7. Chesapeake Bay nitrogen fluxes derived from a land-estuarine ocean biogeochemical modeling system: Model description, evaluation, and nitrogen budgets

    NASA Astrophysics Data System (ADS)

    Feng, Yang; Friedrichs, Marjorie A. M.; Wilkin, John; Tian, Hanqin; Yang, Qichun; Hofmann, Eileen E.; Wiggert, Jerry D.; Hood, Raleigh R.

    2015-08-01

    The Chesapeake Bay plays an important role in transforming riverine nutrients before they are exported to the adjacent continental shelf. Although the mean nitrogen budget of the Chesapeake Bay has been previously estimated from observations, uncertainties associated with interannually varying hydrological conditions remain. In this study, a land-estuarine-ocean biogeochemical modeling system is developed to quantify Chesapeake riverine nitrogen inputs, within-estuary nitrogen transformation processes and the ultimate export of nitrogen to the coastal ocean. Model skill was evaluated using extensive in situ and satellite-derived data, and a simulation using environmental conditions for 2001-2005 was conducted to quantify the Chesapeake Bay nitrogen budget. The 5 year simulation was characterized by large riverine inputs of nitrogen (154 × 109 g N yr-1) split roughly 60:40 between inorganic:organic components. Much of this was denitrified (34 × 109 g N yr-1) and buried (46 × 109 g N yr-1) within the estuarine system. A positive net annual ecosystem production for the bay further contributed to a large advective export of organic nitrogen to the shelf (91 × 109 g N yr-1) and negligible inorganic nitrogen export. Interannual variability was strong, particularly for the riverine nitrogen fluxes. In years with higher than average riverine nitrogen inputs, most of this excess nitrogen (50-60%) was exported from the bay as organic nitrogen, with the remaining split between burial, denitrification, and inorganic export to the coastal ocean. In comparison to previous simulations using generic shelf biogeochemical model formulations inside the estuary, the estuarine biogeochemical model described here produced more realistic and significantly greater exports of organic nitrogen and lower exports of inorganic nitrogen to the shelf.

  8. Inferring nutrient loading of estuarine systems by remote sensing of aquatic vegetation

    NASA Technical Reports Server (NTRS)

    Anderson, R. R.

    1978-01-01

    THe use of remote sensing to record algal and vascular aquatic plant growths in estuarine waters is discussed. A technique is proposed that uses a combination of data to hierarchically classify watersheds with regard to severity of potential pollution. Specific nonpoint sources of nutrients in tributaries of the watershed are identified with lower altitude photography of vegetation and selected ground sampling. It is concluded that excessive growths of some aquatic plants may be related to nutrient pollution.

  9. Catchment controls and human disturbances on the geomorphology of small Mediterranean estuarine systems

    NASA Astrophysics Data System (ADS)

    Estrany, Joan; Grimalt, Miquel

    2014-10-01

    Geographic signatures are physical and human-induced characteristics or processes that identify comparable or unique features of estuaries along latitudinal gradients. In Mediterranean areas, the microtidal regime and the strong seasonal and inter-annual contrasts cause an alternation between relatively high runoff and arid conditions. Furthermore, the long history of human settlement also increases the complexity in the study of these estuarine systems. This study investigates these signatures of the estuaries located within the Mallorcan eastern coast, which are geomorphologically homogeneous because of a similar bedrock geology and Holocene history. A multi-method approach focused on the integration of geomorphometry, hydraulics, historical sources and statistics was used. We explore the role played by catchment morphometric parameters, severe flash flood events and human disturbances in controlling the geomorphology of 10 beach-barrier enclosed, fluvial incised lagoons. Most of the lagoons discharge into 'calas', ranging in size from 1345 to 17,537 m2 and their related catchments are representative of the Mediterranean hydrological systems. Multiple regression models illustrate that the size, slope and drainage network development of the catchments explain the variance in length (r2 = 0.67), volume (r2 = 0.49), area (r2 = 0.64), circularity (r2 = 0.72) and average width (r2 = 0.81) of the lagoons. Depending on these catchment morphometric variables, the shape of the lagoons is also determined by the occurrence of catastrophic flash floods, which cause scouring and dredging, whereas the ordinary flood events and sea storms promote refilling and sedimentation. A historical analysis since 1850 documented 18 flood events, 5 of which were catastrophic with destructive effects along the catchments and large morphological changes in coastal lagoons. High intensity rainfall (up to 200 mm in 2 h), the geomorphometry of the catchments and the massive construction of

  10. Coastal wetland response to sea level rise in a marine and fluvial estuarine system

    NASA Astrophysics Data System (ADS)

    Alizad, K.; Hagen, S. C.; Morris, J. T.; Bilskie, M. V.; Passeri, D. L.; Medeiros, S. C.

    2014-12-01

    . Most of the salt marshes become flooded and some of them migrate under higher SLR scenarios. These examples show how this tool can be used in any estuarine system to project salt marsh productivity and accretion under sea level change scenarios to better interpret responses and improve restoration and planning management decisions.

  11. Superstorm Sandy-related Morphologic and Sedimentologic Changes in an Estuarine System: Barnegat Bay-Little Egg Harbor Estuary, New Jersey

    NASA Astrophysics Data System (ADS)

    Miselis, J. L.; Ganju, N. K.; Navoy, A.; Nicholson, R.; Andrews, B.

    2013-12-01

    Despite the well-recognized ecological importance of back-barrier estuaries, the role of storms in their geomorphic evolution is poorly understood. Moreover, the focus of storm impact assessments is often the ocean shorelines of barrier islands rather than the exchange of sediment from barrier to estuary. In order to better understand and ultimately predict short-term morphologic and sedimentologic changes in coastal systems, a comprehensive research approach is required but is often difficult to achieve given the diversity of data required. An opportunity to use such an approach in assessing the storm-response of a barrier-estuary system occurred when Superstorm Sandy made landfall near Atlantic City, New Jersey on 29 October 2012. Since 2011, the US Geological Survey has been investigating water circulation and water-quality degradation in Barnegat Bay-Little Egg Harbor (BBLEH) Estuary, the southern end of which is approximately 25 kilometers north of the landfall location. This effort includes shallow-water geophysical surveys to map the bathymetry and sediment distribution within BBLEH, airborne topo-bathymetric lidar surveys for mapping the shallow shoals that border the estuary, and sediment sampling, all of which have provided a recent picture of the pre-storm estuarine geomorphology. We combined these pre-storm data with similar post-storm data from the estuary and pre- and post-storm topographic data from the ocean shoreline of the barrier island to begin to understand the response of the barrier-estuary system. Breaches in the barrier island resulted in water exchange between the estuary and the ocean, briefly reducing residence times in the northern part of the estuary until the breaches were closed. Few morphologic changes in water depths greater than 1.5 m were noted. However, morphologic changes observed in shallower depths along the eastern shoreline of the estuary are likely related to overwash processes. In general, surficial estuarine sediments

  12. Multi-element study of sediments from the river Khai River - Nha Trang Bay estuarine system, South China Sea.

    NASA Astrophysics Data System (ADS)

    Koukina, Sofia; Lobus, Nikolai; Peresypkin, Valery; Baturin, Gleb; Smurov, Andrey

    2013-04-01

    Major (Al, Fe, Ti, Mg, Ca, Na, K), minor (Mn) and trace (Cr, Ni, Cd, V, Zn, Cu, Pb, Sb, Bi, Sn, Ag, Li, Co, As, Zr, Mo, Hg) elements along with nutrients (TOC, TS, TP) and TIC were first determined in ten surface sediment samples from the Khai River - Nha Trang Bay estuarine system, South China Sea. According to the sediment quality guidelines and reference background values, most of the element contents that were studied were below the threshold levels, while the content of Ag exceeded significantly the hazardous levels in the most of the samples along the river - sea transect. The local anthropogenic and/or environmental sources of Ag within the region need special study. Aluminum and lithium normalization indicated some specific features in the abundance and distribution of the elements along the salinity gradient. The mean grain size of the sediments decreased from the river part to the bay part of the transect. Sedimentary TOC was relatively low (1-2 %) and showed independent distribution along the river - sea transect in relation to the other elements that were studied. Ca, Ba and Sr distribution showed some sporadic enrichment and were largely controlled by the TIC content in sediments. Sedimentary TP, Al, Fe, Mn, Ti, Na, K, Li, Co, Cs, Zn and V varied within the narrow range and tended to increase seaward. These elements are most likely controlled by the accumulation of their fine grained aluminosilicate host minerals and materials at sites determined by hydrodynamic conditions, i. e., in the sea floor depression. TS, As, Sn, Bi, U, Cd and Mo were relatively low in the sediments studied and tended to decrease seaward with the slight elevation in the intermediate part of the transect. These elements can be scavenged by and/or co-precipitated with the dissolved and particulate materials of the river discharge and further deposited on the river - sea geochemical barrier in the course of estuarine sedimentation. The distribution of Ni, Cr, Zr Cu, Pb, Sb, Hg and

  13. Contaminant Interactions and Biological Effects of Single-walled Carbon Nanotubes in a Benthic Estuarine System

    NASA Astrophysics Data System (ADS)

    Parks, Ashley Nicole

    The fate, bioavailability, bioaccumulation and toxicity of single-walled carbon nanotubes (SWNT) have not been extensively studied to date. Pristine SWNT are highly hydrophobic and have been shown to strongly associate with natural particulate matter in aquatic environments. In light of this, I have focused my research to examine the influence of sediment and food exposure routes on bioavailability, bioaccumulation, and toxicity of structurally diverse SWNT in several ecologically-important marine invertebrate species. No significant mortality was observed in any organism at concentrations up to 1000 mg/kg. Evidence of biouptake after ingestion was observed for pristine semiconducting SWNT using NIRF spectroscopy and for oxidized 14C-SWNT using liquid scintillation counting. After a 24 hour depuration period, the pristine semiconducting SWNT were eliminated from organisms to below the method detection limit (5 microg/mL), and the 14C-SWNT body burden was decreased by an order of magnitude to a bioaccumulation factor (BAF) of <0.01. Neither pristine SWNT nor oxidized 14C-SWNT caused environmentally relevant toxicity or bioaccumulation in benthic invertebrates. Overall, the SWNT were not bioavailable and appear to associate with the sediment. In addition to investigating the toxicity and bioaccumulation of SWNT as an independent toxicant, it is important to consider how they will interact with other contaminants in the environment (i.e., increase or decrease toxicity and bioaccumulation of co-contaminants, alter the environmental transport of co-contaminants, induce degradation of co-contaminants, etc.). I wanted to investigate the effects of SWNT on a complex mixture of contaminants already present in a natural system. New Bedford Harbor (NBH) sediment, which is contaminated with polychlorinated biphenyls (PCBs), was amended with pristine SWNT to determine if the presence of SWNT would mitigate the toxicity and bioaccumulation of the PCBs in deposit

  14. Quantification of Sterol and Triterpenol Biomarkers in Sediments of the Cananéia-Iguape Estuarine-Lagoonal System (Brazil) by UHPLC-MS/MS.

    PubMed

    Bataglion, Giovana Anceski; Koolen, Hector Henrique Ferreira; Weber, Rolf Roland; Eberlin, Marcos Nogueira

    2016-01-01

    Sterols and triterpenols present in sedimentary cores from 12 stations along the Cananéia-Iguape estuarine-lagoonal system were investigated by ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). Ten sterols and three triterpenols were identified and quantified, indicating both natural and anthropogenic sources. The relative distributions of sterol and triterpenol showed that the study area is submitted to organic matter (OM) from the Ribeira de Iguape River, seawater, surrounding vegetation, and plankton production. The contribution of these sources depends on the region of the estuarine-lagoonal system and the depth of sediment. Regarding anthropogenic sources, only the samples submitted to freshwater flow from the Ribeira de Iguape River presented concentration of coprostanol higher than the threshold value and diagnostic ratios, coprostanol/(coprostanol + cholestanol) and coprostanol/cholesterol, that indicate moderate contamination by domestic sewage in that area of the estuarine-lagoonal system. Therefore, the approach used herein identified the OM sources and its transport along the Cananéia-Iguape estuarine-lagoonal system (Brazil), which is a complex of lagoonal channels located in a United Nations Educational, Scientific and Cultural Organization (UNESCO) Biosphere Reserve. PMID:27087811

  15. Quantification of Sterol and Triterpenol Biomarkers in Sediments of the Cananéia-Iguape Estuarine-Lagoonal System (Brazil) by UHPLC-MS/MS

    PubMed Central

    Bataglion, Giovana Anceski; Koolen, Hector Henrique Ferreira; Weber, Rolf Roland; Eberlin, Marcos Nogueira

    2016-01-01

    Sterols and triterpenols present in sedimentary cores from 12 stations along the Cananéia-Iguape estuarine-lagoonal system were investigated by ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). Ten sterols and three triterpenols were identified and quantified, indicating both natural and anthropogenic sources. The relative distributions of sterol and triterpenol showed that the study area is submitted to organic matter (OM) from the Ribeira de Iguape River, seawater, surrounding vegetation, and plankton production. The contribution of these sources depends on the region of the estuarine-lagoonal system and the depth of sediment. Regarding anthropogenic sources, only the samples submitted to freshwater flow from the Ribeira de Iguape River presented concentration of coprostanol higher than the threshold value and diagnostic ratios, coprostanol/(coprostanol + cholestanol) and coprostanol/cholesterol, that indicate moderate contamination by domestic sewage in that area of the estuarine-lagoonal system. Therefore, the approach used herein identified the OM sources and its transport along the Cananéia-Iguape estuarine-lagoonal system (Brazil), which is a complex of lagoonal channels located in a United Nations Educational, Scientific and Cultural Organization (UNESCO) Biosphere Reserve. PMID:27087811

  16. Solutions Network Formulation Report. The Potential Contribution of the International GPM Program to the NOAA Estuarine Reserves Division's System-wide Monitoring Program

    NASA Technical Reports Server (NTRS)

    Hilbert, Kent; Anderson, Daniel; Lewis, David

    2007-01-01

    Data collected via the International GPM Program could be used to provide a solution for the NOAA Estuarine Reserves Division s System-wide Monitoring Program by augmenting in situ rainfall measurements with data acquired via future satellite-acquired precipitation data. This Candidate Solution is in alignment with the Coastal Management National Application and will benefit society by assisting in estuary preservation.

  17. The Future of Southern Ocean Observing Systems

    NASA Astrophysics Data System (ADS)

    Talley, L. D.

    2015-12-01

    Knowledge of the Southern Ocean's role in global climate from seasonal to millennial timescales is evolving, with rapidly increasing recognition of the centrality of the Southern Ocean to Earth's heat, carbon, nutrient, and freshwater budgets, and of the impact of interactions between the ocean and the major ice shelves and grounded ice sheets of Antarctica, which have been decreasing in mass. Observations in this data-sparse and logistically remote region have never been so important, and many nations are rising to the challenge of supporting both experiments and long-term sustained observations. As illustrated in the figure from Meredith et al. (Current Op. Env. Sustain. 2013), autonomous in situ technologies are at the fore because of the difficulty and expense of sending ships year-round and because the crucial satellite remote sensing must be accompanied by in situ observations, including beneath sea ice and ice shelves. The Southern Ocean Observing System (SOOS) has grown out of this recognized need for coordinated observations from the Antarctic coastline northward to the subtropics, from the bottom water production regions in coastal polynyas over the continental shelves, to the regions of interaction of warm ocean waters with Antarctic ice shelves, beneath the vast seasonal sea ice region, and in the hot spots of air-sea fluxes and cross-Antarctic Circumpolar Current (ACC) mixing where the ACC interacts with topography and continental boundaries. The future includes international coordination and collaboration and strengthening of new and existing technologies, which include satellite observing, ice-enabled profiling floats, profiling from marine mammals, moored measurements in many strategic locations, glider and other autonomous operations in all regions, and drilling through floating ice shelves to measure the ocean waters below. Improved and consistent weather observations around the Antarctic coastlines will improve forecasting and reanalysis. Ice

  18. DEVELOPMENT OF NITROGEN LOADING - RESPONSE RELATIONSHIPS FOR ESTUARINE WATERS USING AN EMPIRICAL COMPARATIVE SYSTEMS APPROACH

    EPA Science Inventory

    The U.S. EPA Atlantic Ecology Division (AED) has initiated a multi-year research program to develop empirical nitrogen load-response models for embayments in southern New England. This is part of a multi-regional effort to develop nutrient load-response models for the Gulf of Mex...

  19. PROCEEDINGS OF THE 28TH SOUTHERN CONSERVATION SYSTEMS CONFERENCE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The steering committee of the Southern Conservation Tillage Conference for Sustainable Agriculture emphasized the need for a systems approach for optimum production and profit with the name change to the Southern Conservation Tillage Systems Conference held at Florence, SC. During the Florence confe...

  20. Numerical modeling of tides in the Great Bay Estuarine System: dynamical balance and spring-neap residual modulation

    NASA Astrophysics Data System (ADS)

    McLaughlin, J. W.; Bilgili, A.; Lynch, D. R.

    2003-05-01

    The Great Bay Estuarine System, in New Hampshire, USA, has been the focus area for an attempt to develop a robust finite element method model for estuarine hydrodynamics. Past studies used a nonlinear, time stepping, kinematic model with limited success (Ip et al. Advances in fluid mechanics III, WIT, Southampton (2000) 569; Bilgili et al. J. Geophys. Res. - Oceans 107 (2002); Ertürk et al. Estuar. Coast. Shelf Sci. 47 (1998) 119). We add dynamic physics (that is, local accelerations) for deep-water areas and keep kinematic physics (that is, without local and advective accelerations), with the inclusion of a porous medium beneath the open channel, for shallow and dewatering areas. The choice of which physics set to apply is made on an elemental depth dependent basis. The addition of the local acceleration terms for deep-water areas is seen to greatly improve accuracy in matching of tidal phasing over previous studies. Simulations involving M 2/M 4/M 6 tidal constituents result in strong agreement to observed data from the 1975 Great Bay field program (Swift & Brown, Estuar. Coast. Shelf Sci. 17 (1983) 297), in terms of both tidal heights and cross-section averaged velocities. Comparisons with 10 tidal elevation observation stations and four cross-section averaged current transects show good agreement, displaying average normalized root mean square misfit values of 0.08 and 0.25, respectively. Study of the simulated momentum balance shows the size of the contributions from acceleration terms to be on the order of a third the size of the contributions from the pressure gradient and bottom stress terms. Although relatively small, they are observed to peak at the crucial time of tidal reversal. Application of the model for long-term simulation using an M 2/N 2/S 2 forcing shows the ability to realistically capture the spring-neap cycle. The tidally rectified flow is generally described as a constant spatial pattern with overall amplitude modulation following the

  1. Complexity of the flooding/drying process in an estuarine tidal-creek salt-marsh system: An application of FVCOM

    NASA Astrophysics Data System (ADS)

    Chen, Changsheng; Qi, Jianhua; Li, Chunyan; Beardsley, Robert C.; Lin, Huichan; Walker, Randy; Gates, Keith

    2008-07-01

    The tidal flooding/drying process in the Satilla River Estuary was examined using an unstructured-grid finite-volume coastal ocean model (FVCOM). Driven by tidal forcing at the open boundary and river discharge at the upstream end, FVCOM produced realistic tidal flushing in this estuarine tidal-creek intertidal salt-marsh complex, amplitudes and phases of the tidal wave, and salinity observed at mooring sites and along hydrographic transects. The model-predicted residual flow field is characterized by multiscale eddies in the main channel, which are verified by ship-towed ADCP measurements. To examine the impact of complex coastal geometry on water exchange in an estuarine tidal-creek salt-marsh system, FVCOM was compared with our previous structured-grid finite difference Satilla River Estuary model (ECOM-si). The results suggest that by failing to resolve the complex coastal geometry of tidal creeks, barriers and islands, a model can generate unrealistic flow and water exchange and thus predict the wrong dynamics for this estuary. A mass-conservative unstructured-grid model is required to accurately and efficiently simulate tidal flow and flushing in a complex geometrically controlled estuarine dynamical system.

  2. Characteristics of Southern California coastal aquifer systems

    USGS Publications Warehouse

    Edwards, B.D.; Hanson, R.T.; Reichard, E.G.; Johnson, T.A.

    2009-01-01

    Most groundwater produced within coastal Southern California occurs within three main types of siliciclastic basins: (1) deep (>600 m), elongate basins of the Transverse Ranges Physiographic Province, where basin axes and related fluvial systems strike parallel to tectonic structure, (2) deep (>6000 m), broad basins of the Los Angeles and Orange County coastal plains in the northern part of the Peninsular Ranges Physiographic Province, where fluvial systems cut across tectonic structure at high angles, and (3) shallow (75-350 m), relatively narrow fluvial valleys of the generally mountainous southern part of the Peninsular Ranges Physiographic Province in San Diego County. Groundwater pumped for agricultural, industrial, municipal, and private use from coastal aquifers within these basins increased with population growth since the mid-1850s. Despite a significant influx of imported water into the region in recent times, groundwater, although reduced as a component of total consumption, still constitutes a significant component of water supply. Historically, overdraft from the aquifers has caused land surface subsidence, flow between water basins with related migration of groundwater contaminants, as well as seawater intrusion into many shallow coastal aquifers. Although these effects have impacted water quality, most basins, particularly those with deeper aquifer systems, meet or exceed state and national primary and secondary drinking water standards. Municipalities, academicians, and local water and governmental agencies have studied the stratigraphy of these basins intensely since the early 1900s with the goals of understanding and better managing the important groundwater resource. Lack of a coordinated effort, due in part to jurisdictional issues, combined with the application of lithostratigraphic correlation techniques (based primarily on well cuttings coupled with limited borehole geophysics) have produced an often confusing, and occasionally conflicting

  3. Gold coast seaway smartrelease decision support system: optimising recycled water release in a sub tropical estuarine environment.

    PubMed

    Stuart, G; Hollingsworth, A; Thomsen, F; Szylkarski, S; Khan, S; Tomlinson, R; Kirkpatrick, S; Catterall, K; Capati, B

    2009-01-01

    Gold Coast Water is responsible for the management of the water, recycled water and wastewater assets of the City of the Gold Coast on Australia's east coast. Excess treated recycled water is released at the Gold Coast Seaway, a man-made channel connecting the Broadwater Estuary with the Pacific Ocean, on an outgoing tide in order for the recycled water to be dispersed before the tide changes and re-enters the Broadwater estuary. Rapid population growth has placed increasing demands on the city's recycled water release system and an investigation of the capacity of the Broadwater to assimilate a greater volume of recycled water over a longer release period was undertaken in 2007. As an outcome, Gold Coast Water was granted an extension of the existing release licence from 10.5 hours per day to 13.3 hours per day from the Coombabah wastewater treatment plant (WWTP). The Seaway SmartRelease Project has been designed to optimise the release of the recycled water from the Coombabah WWTP in order to minimise the impact to the receiving estuarine water quality and maximise the cost efficiency of pumping. In order achieve this; an optimisation study that involves intensive hydrodynamic and water quality monitoring, numerical modelling and a web-based decision support system is underway. An intensive monitoring campaign provided information on water levels, currents, winds, waves, nutrients and bacterial levels within the Broadwater. This data was then used to calibrate and verify numerical models using the MIKE by DHI suite of software. The Decision Support System will then collect continually measured data such as water levels, interact with the WWTP SCADA system, run the numerical models and provide the optimal time window to release the required amount of recycled water from the WWTP within the licence specifications. PMID:19844054

  4. Movement patterns of Brook Trout in a restored coastal stream system in southern Massachusetts

    USGS Publications Warehouse

    Snook, Erin L.; Letcher, Benjamin H.; Dubreuil, Todd L.; Zydlewski, Joseph; O'Donnell, Matthew J.; Whiteley, Andrew R.; Hurley, Stephen T.; Danylchuk, Andy J.

    2016-01-01

    Coastal Brook Trout (Salvelinus fontinalis) populations are found from northern Canada to New England. The extent of anadromy generally decreases with latitude, but the ecology and movements of more southern populations are poorly understood. We conducted a 33-month acoustic telemetry study of Brook Trout in Red Brook, MA, and adjacent Buttermilk Bay (marine system) using 16 fixed acoustic receivers and surgically implanting acoustic transmitters in 84 individuals. Tagged Brook Trout used the stream, estuary (50% of individuals) and bay (10% of individuals). Movements into full sea water were brief when occurring. GAMM models revealed that transitions between habitat areas occurred most often in spring and fall. Environmental data suggest that use of the saline environment is limited by summer temperatures in the bay. Movements may also be related to moon phase. Compared to more northern coastal populations of Brook Trout, the Red Brook population appears to be less anadromous overall, yet the estuarine segment of the system may have considerable ecological importance as a food resource.

  5. Hydrothermal system in Southern Grass Valley, Pershing County, Nevada

    SciTech Connect

    Welch, A.H.; Sorey, M.L.; Olmsted, F.H.

    1981-01-01

    Southern Grass Valley is a fairly typical extensional basin in the Basin and Range province. Leach Hot Springs, in the southern part of the valley, represents the discharge end of an active hydrothermal flow system with an estimated deep aquifer temperature of 163 to 176/sup 0/C. Results of geologic, hydrologic, geophysical and geochemical investigations are discussed in an attempt to construct an internally consistent model of the system.

  6. Spatial patterns in soil biogeochemical process rates along a Louisiana wetland salinity gradient in the Barataria Bay estuarine system

    NASA Astrophysics Data System (ADS)

    Roberts, B. J.; Rich, M. W.; Sullivan, H. L.; Bledsoe, R.; Dawson, M.; Donnelly, B.; Marton, J. M.

    2014-12-01

    Louisiana has the highest rates of coastal wetland loss in the United States. In addition to being lost, Louisiana wetlands experience numerous other environmental stressors including changes in salinity regime (both increases from salt water intrusion and decreases from the creation of river diversions) and climate change induced changes in vegetation (e.g. the northward expansion of Avicennia germinans (black mangrove) into salt marshes). In this study, we examined how these changes might influence biogeochemical process rates important in regulating carbon balance and the cycling, retention, and removal of nutrients in Louisiana wetlands. Specifically, we measured net soil greenhouse gas fluxes and collected cores for the determination of rates of greenhouse gas production, denitrification potential, nitrification potential, iron reduction, and phosphorus sorption from surface (0-5cm) and subsurface (10-15cm) depths for three plots in each of 4 sites along the salinity gradient: a freshwater marsh site, a brackish (7 ppt) marsh site, a salt marsh (17 ppt), and a Avicennia germinans stand (17 ppt; adjacent to salt marsh site) in the Barataria Bay estuarine system. Most biogeochemical processes displayed similar spatial patterns with salt marsh rates being lower than rates in freshwater and/or brackish marsh sites and not having significantly different rates than in Avicennia germinans stands. Rates in surface soils were generally higher than in subsurface soils. These patterns were generally consistent with spatial patterns in soil properties with soil water content, organic matter quantity and quality, and extractable nutrients generally being higher in freshwater and brackish marsh sites than salt marsh and Avicennia germinans sites, especially in surface soils. These spatial patterns suggest that the ability of coastal wetlands to retain and remove nutrients might change significantly in response to future climate changes in the region and that these

  7. Classification for Estuarine Ecosystems: A Review and Comparison of Selected Classification Schemes

    EPA Science Inventory

    Estuarine scientists have devoted considerable effort to classifying coastal, estuarine and marine environments and their watersheds, for a variety of purposes. These classifications group systems with similarities – most often in physical and hydrodynamic properties – in order ...

  8. Estuarine Food Webs

    EPA Science Inventory

    Estuaries provide habitat for abundant plants, animals and micro-organisms, ranging from microscopic plankton (bacteria, yeasts, algae, protozoa) to larger benthic and pelagic organisms (seagrass, clams, crabs, sea trout, pelicans and dolphins). Estuarine biota can be characteri...

  9. Considerations on the effects of tidal regimes in the movement of floating litter in an estuarine environment: Case study of the estuarine system of Santos-São Vicente, Brazil.

    PubMed

    Fernandino, Gerson; Elliff, Carla Isobel; Frutuoso, Gabriela Amado; Silva, Eric Vinícius Nascimento Malaquias da; Gama, Guilherme Santiago; Sousa, João Henrique de Oliveira; Silva, Iracema Reimão

    2016-09-15

    Floating litter in the estuarine system of Santos-São Vicente is common and is part of day-to-day activities of various users of the area. The objective of the present study was to carry out a quali-quantitative evaluation of the occurrence of floating litter, to infer their sources, and to identify environmental factors that are likely to control occurrence and distribution, with particular emphasis on the effects of tidal regimes. Six sampling stations were selected along the aforementioned estuary and visited monthly between July 2010 and January 2012. Floating litter was counted from a fixed sampling station. Plastics prevailed (89.64%) and their main source was domestic activities (55.41%). More litter was found during ebb spring tides, with higher concentrations obeying confluence patterns of the estuary's channels. Results indicated that occurrence can be attributed to the deficiency in basic sewage system in the area and the deliberate disposal into the estuary by the local population. PMID:27263980

  10. Multi-Scale Response of the Shelf-Estuarine-Wetland to Severe Weather: A Fully Wave-Current Coupled FVCOM System

    NASA Astrophysics Data System (ADS)

    Chen, C.; Beardsley, R. C.; Qi, J.; Lai, Z.; Xu, Q.; Lin, H.; Xu, Y.

    2012-12-01

    The response of the coastal ocean and estuaries to severe weather forcing (e.g. tropical and extra-tropical storms) and strong tsunamis vary significantly in space and time. Simulating and predicting this response require a) a fully coupled atmospheric-ocean model system that can resolve the multi-scale current-wave interaction processes; b) grid flexibility to accurately represent irregular geometric shelf-estuarine-wetland regions, c) computational efficiency that allows an adjustable time step with changes in the model spatial resolution, and d) a Web Map Service (WMS) display system. The UMASSD-WHOI research team has upgraded FVCOM using the Earth System Modeling Framework (ESMF). The new FVCOM has a mass-conservative two-way nesting feature that allows varying time steps for the time integration of different multi-scale global, basin, shelf, and estuarine/wetland processes. A parallelized version of WMS was also built into FVCOM, through which the model forecast fields can be viewed and analyzed directly using Google maps on the website. These new features have been implemented into the Northeast Coastal Ocean Forecast System (NECOFS) for the purpose of predicting coastal inundation caused by severe weather systems as they pass through the Northeast. The multi-domain nesting FVCOM system was also successfully used to simulate the Japan March 11 earthquake-induced tsunami waves, coastal inundation, and subsequent spread of Cs-137 into the Japan coastal ocean.

  11. An integrated East China Sea-Changjiang Estuary model system with aim at resolving multi-scale regional-shelf-estuarine dynamics

    NASA Astrophysics Data System (ADS)

    Ge, Jianzhong; Ding, Pingxing; Chen, Changsheng; Hu, Song; Fu, Gui; Wu, Lunyu

    2013-08-01

    A high-resolution numerical model system is essential to resolve multi-scale coastal ocean dynamics. So a multi-scale unstructured grid-based finite-volume coastal ocean model (FVCOM) system has been established for the East China Sea and Changjiang Estuary (ECS-CE) with the aim at resolving coastal ocean dynamics and understanding different physical processes. The modeling system consists of a three-domain-nested weather research and forecasting model, FVCOM model with the inclusion of FVCOM surface wave model in order to understand the wave-current interactions. The ECS-CE system contains three different scale models: a shelf-scale model for the East China Sea, an estuarine-scale model for the Changjiang Estuary and adjacent region, and a fine-scale model for the deep waterway regions. These three FVCOM-based models guarantee the conservation of mass and momentum transferring from outer domain to inner domain using the one-way common-grid nesting procedure. The model system has been validated using data from various observation data, including surface wind, tides, currents, salinity, and wave to accurately reveal the multi-scale dynamics of the East China Sea and Changjiang Estuary. This modeling system has been demonstrated via application to the seasonal variations of Changjiang diluted water and the bottom saltwater intrusion in the North Passage, and it shows strong potential for estuarine and coastal ocean dynamics and operational forecasting.

  12. The estuarine geochemical reactivity of Zn isotopes and its relevance for the biomonitoring of anthropogenic Zn and Cd contaminations from metallurgical activities: Example of the Gironde fluvial-estuarine system, France

    NASA Astrophysics Data System (ADS)

    Petit, Jérôme C. J.; Schäfer, Jörg; Coynel, Alexandra; Blanc, Gérard; Chiffoleau, Jean-François; Auger, Dominique; Bossy, Cécile; Derriennic, Hervé; Mikolaczyk, Mathilde; Dutruch, Lionel; Mattielli, Nadine

    2015-12-01

    geochemical reactivity of Zn in the estuary rather than signatures of past metallurgical contaminations in the watershed as recorded in contaminated river sediments. The study also shows that the isotopic composition of Zn is strongly fractionated by its geochemical reactivity in the Gironde Estuary, representative of meso-macrotidal estuarine systems.

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

    NASA Astrophysics Data System (ADS)

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

    2012-03-01

    The Mondego estuary is a mainly polyhaline estuary in central Portugal in which eutrophication increased during the last decades of the 20th century. In 1998 the system hydrology was changed, aiming to reverse the eutrophication process. A long environmental monitoring database showed that the mean concentrations of dissolved inorganic phosphorus (DIP) increased by 50%, due to the increase in winter concentrations, i.e., in periods characterized by lower temperature and lower salinity. Given existing background knowledge, especially on the system hydrodynamics, phosphorus dynamics and phosphorus speciation in the estuary, we framed the hypothesis that the significant increase of DIP could be related to different sorption capacities of the sediments. The results highlighted two scenarios: i) Before 1998 the nutrient-rich freshwater input from the upstream cultivated lands entered the system through the area with the highest PO4-P adsorption capacity (Q∗ = 657 μg P g-1 wwt), thus the PO4-P availability in the water column was mostly dependent on the mineralization processes, which is in agreement with previous findings; ii) After 1998, the water residence time diminished from moderate (weeks) to short (days). This change coincided with a diversion of the water to an area with a much lower PO4-P adsorption capacity (Q∗ = 410 μg P g-1 wwt), which represented a decrease in 7.3% of the system adsorption capacity. This means that sediments were not able to adsorb much of the PO4-P and a higher equilibrium concentration occurred in the water column. The sorption study proved to be a valuable tool in testing our hypothesis and provided essential information on the mobility of PO4-P from soils/sediments to the water column.

  14. Final Report Collaborative Project. Improving the Representation of Coastal and Estuarine Processes in Earth System Models

    SciTech Connect

    Bryan, Frank; Dennis, John; MacCready, Parker; Whitney, Michael

    2015-11-20

    This project aimed to improve long term global climate simulations by resolving and enhancing the representation of the processes involved in the cycling of freshwater through estuaries and coastal regions. This was a collaborative multi-institution project consisting of physical oceanographers, climate model developers, and computational scientists. It specifically targeted the DOE objectives of advancing simulation and predictive capability of climate models through improvements in resolution and physical process representation. The main computational objectives were: 1. To develop computationally efficient, but physically based, parameterizations of estuary and continental shelf mixing processes for use in an Earth System Model (CESM). 2. To develop a two-way nested regional modeling framework in order to dynamically downscale the climate response of particular coastal ocean regions and to upscale the impact of the regional coastal processes to the global climate in an Earth System Model (CESM). 3. To develop computational infrastructure to enhance the efficiency of data transfer between specific sources and destinations, i.e., a point-to-point communication capability, (used in objective 1) within POP, the ocean component of CESM.

  15. Siak River System — East-Sumatra: Characterisation of sources, estuarine processes, and discharge into the Malacca Strait

    NASA Astrophysics Data System (ADS)

    Siegel, Herbert; Stottmeister, Iris; Reißmann, Jan; Gerth, Monika; Jose, Christin; Samiaji, Joco

    2009-04-01

    Interdisciplinary pollution studies were performed in the Siak River system in the Riau Province of East-Sumatra (Indonesia). Remote sensing investigations combined with in situ measurements in different seasons of the years 2004-2006 were focused on the identification of different sources of water masses in the tributaries and on the discharge into the estuary and Malacca Strait. Ship-borne measurements comprised the determination of the concentration and composition of optically active water constituents and water colour. Satellite data of different spectral and spatial resolution were implemented. Sources of different water masses such as humic substance dominated rivers, erosion areas of high suspended matter concentration and areas of limited bio-productivity are identified. Sources of humic substances are the rivers Tapung Kanan, Mandau, Siak Kecil, and Bukit Batu which are draining peatlands. The absorption coefficients of dissolved organic substances are partly (Siak Kecil, 51.8 m - 1 ) more than double of the currently admitted coefficients. The highest suspended matter concentrations near a channel between Siak and Siak Kecil leading to lowest transparency are caused by the estuarine turbidity maximum developing at the tidal front. The lowest Chlorophyll concentrations were measured between Pekanbaru and the channel, in and downstream of an industrial area. The concentration and distribution of water constituents are characterised by distinct regional patterns independent from the monsoon phases. The high absorption of dissolved organic humic substances originated from draining peatlands shifts the maximum of spectral reflectances to 700 nm leading to the extreme brownish to red-brownish water colour. High scattering of suspended particles increases the reflectance in the entire spectral range. The strong changes in the water colour enables satellite data of the visible spectral range to follow the distribution patterns of the Siak River discharge in the

  16. OVERVIEW OF GIS APPLICATIONS IN ESTUARINE MONITORING AND ASSESSMENT RESEARCH

    EPA Science Inventory

    Geographic information systems (GIS) tools are now considered integral in estuarine monitoring and assessment research. A synopsis is presented of our estuarine applications of GIS in the Northeast region of the U.S. The applications discussed cover sample site selection, support...

  17. The effect of wind and currents on gas exchange in an estuarine system

    NASA Technical Reports Server (NTRS)

    Broecker, W. S.; Ledwell, J. R.; Bopp, R.

    1987-01-01

    The objectives were to develop a non-volatile tracer to use in gas exchange experiments in laterally unconfined systems and to study applications of deliberate tracers in limnology and oceanography. Progress was made on both fronts but work on the development of the non-volatile tracer proved to be more difficult and labor intensive that anticipated so no field experiments using non-volatile tracers was performed as yet. In the search for a suitable non-volatile tracer for an ocean scale gas exchange experiment a tracer was discovered which does not have the required sensitivity for a large scale experiment, but is very easy to analyze and will be well suited for smaller experiments such as gas exchange determinations on rivers and streams. Sulfur hexafluoride, SF6, was used successfully as a volatile tracer along with tritium as a non-volatile tracer to study gas exchange rates from a primary stream. This is the first gas exchange experiment in which gas exchange rates were determined on a head water stream where significant groundwater input occurs along the reach. In conjunction with SF6, Radon-222 measurements were performed on the groundwater and in the stream. The feasibility of using a combination of SF6 and radon is being studied to determine groundwater inputs and gas exchange of rates in streams with significant groundwater input without using a non-volatile tracer.

  18. 15 CFR 921.52 - Promotion and coordination of estuarine research.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... AND COASTAL RESOURCE MANAGEMENT NATIONAL ESTUARINE RESEARCH RESERVE SYSTEM REGULATIONS Special Research Projects § 921.52 Promotion and coordination of estuarine research. (a) NOAA will promote and... estuarine research. 921.52 Section 921.52 Commerce and Foreign Trade Regulations Relating to Commerce...

  19. 15 CFR 921.52 - Promotion and coordination of estuarine research.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... AND COASTAL RESOURCE MANAGEMENT NATIONAL ESTUARINE RESEARCH RESERVE SYSTEM REGULATIONS Special Research Projects § 921.52 Promotion and coordination of estuarine research. (a) NOAA will promote and... estuarine research. 921.52 Section 921.52 Commerce and Foreign Trade Regulations Relating to Commerce...

  20. 15 CFR 921.52 - Promotion and coordination of estuarine research.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... AND COASTAL RESOURCE MANAGEMENT NATIONAL ESTUARINE RESEARCH RESERVE SYSTEM REGULATIONS Special Research Projects § 921.52 Promotion and coordination of estuarine research. (a) NOAA will promote and... estuarine research. 921.52 Section 921.52 Commerce and Foreign Trade Regulations Relating to Commerce...

  1. 15 CFR 921.52 - Promotion and coordination of estuarine research.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... AND COASTAL RESOURCE MANAGEMENT NATIONAL ESTUARINE RESEARCH RESERVE SYSTEM REGULATIONS Special Research Projects § 921.52 Promotion and coordination of estuarine research. (a) NOAA will promote and... estuarine research. 921.52 Section 921.52 Commerce and Foreign Trade Regulations Relating to Commerce...

  2. 15 CFR 921.52 - Promotion and coordination of estuarine research.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... AND COASTAL RESOURCE MANAGEMENT NATIONAL ESTUARINE RESEARCH RESERVE SYSTEM REGULATIONS Special Research Projects § 921.52 Promotion and coordination of estuarine research. (a) NOAA will promote and... estuarine research. 921.52 Section 921.52 Commerce and Foreign Trade Regulations Relating to Commerce...

  3. Perspectives on the microbial carbon pump with special reference to microbial respiration and ecosystem efficiency in large estuarine systems

    NASA Astrophysics Data System (ADS)

    Dang, H.; Jiao, N.

    2014-07-01

    Although respiration-based oxidation of reduced carbon releases CO2 into the environment, it provides an ecosystem with the metabolic energy for essential biogeochemical processes, including the newly proposed microbial carbon pump (MCP). The efficiency of MCP in heterotrophic microorganisms is related to the mechanisms of energy transduction employed and hence is related to the form of respiration utilized. Anaerobic organisms typically have lower efficiencies of energy transduction and hence lower efficiencies of energy-dependent carbon transformation. This leads to a lower MCP efficiency on a per-cell basis. Substantial input of terrigenous nutrients and organic matter into estuarine ecosystems typically results in elevated heterotrophic respiration that rapidly consumes dissolved oxygen, potentially producing hypoxic and anoxic zones in the water column. The lowered availability of dissolved oxygen and the excessive supply of nutrients such as nitrate from river discharge lead to enhanced anaerobic respiration processes such as denitrification and dissimilatory nitrate reduction to ammonium. Thus, some nutrients may be consumed through anaerobic heterotrophs, instead of being utilized by phytoplankton for autotrophic carbon fixation. In this manner, eutrophied estuarine ecosystems become largely fueled by anaerobic respiratory pathways and their efficiency is less due to lowered ecosystem productivity when compared to healthy and balanced estuarine ecosystems. This situation may have a negative impact on the ecological function and efficiency of the MCP which depends on the supply of both organic carbon and metabolic energy. This review presents our current understanding of the MCP mechanisms from the view point of ecosystem energy transduction efficiency, which has not been discussed in previous literature.

  4. Environmental studies on river water quality with reference to suitability for agricultural purposes: Mahanadi river estuarine system, India--a case study.

    PubMed

    Sundaray, Sanjay Kumar; Nayak, Binod Bihari; Bhatta, Dinabandhu

    2009-08-01

    Hydrochemistry of surface water (pH, specific conductance, total dissolved solids, sulfate, chloride, nitrate, bicarbonate, hardness, calcium, magnesium, sodium, potassium) in the Mahanadi river estuarine system, India was used to assess the quality of water for agricultural purposes. The samples were studied for 31 different stations during six different seasons in the years 2001-2003. Chemical data were used for mathematical calculations (SAR, Na%, RSC, potential salinity, permeability index, Kelly's index, magnesium hazard, osmotic pressure and salt index) for better understanding the suitability river water quality for agricultural purposes. The river water is free from nitrate-nitrogen hazard and has much less osmotic pressure and RSC values. Further there is no complete precipitation of calcium and magnesium in the study area. The results revealed that waters of some polluted stations like Sambalpur down (D/s of Sambalpur town) and Kathjodi (Cuttack) down (D/s of Cuttack town) are unsuitable up to some extent, where as it is quite unsuitable in case of estuarine samples during the pre-monsoon and post-monsoon seasons. The results were verified by USSL and Wilcox diagrams, which show all the fresh water zone samples (low-medium salinity with low sodium) of the study area are in the 'Excellent to good' category and are suitable to irrigate all soils for semi-tolerant and tolerant as well as sensitive crops. PMID:18670901

  5. An observing system simulation for Southern Ocean carbon dioxide uptake.

    PubMed

    Majkut, Joseph D; Carter, Brendan R; Frölicher, Thomas L; Dufour, Carolina O; Rodgers, Keith B; Sarmiento, Jorge L

    2014-07-13

    The Southern Ocean is critically important to the oceanic uptake of anthropogenic CO2. Up to half of the excess CO2 currently in the ocean entered through the Southern Ocean. That uptake helps to maintain the global carbon balance and buffers transient climate change from fossil fuel emissions. However, the future evolution of the uptake is uncertain, because our understanding of the dynamics that govern the Southern Ocean CO2 uptake is incomplete. Sparse observations and incomplete model formulations limit our ability to constrain the monthly and annual uptake, interannual variability and long-term trends. Float-based sampling of ocean biogeochemistry provides an opportunity for transforming our understanding of the Southern Ocean CO2 flux. In this work, we review current estimates of the CO2 uptake in the Southern Ocean and projections of its response to climate change. We then show, via an observational system simulation experiment, that float-based sampling provides a significant opportunity for measuring the mean fluxes and monitoring the mean uptake over decadal scales. PMID:24891388

  6. Marine and Estuarine Pollution.

    ERIC Educational Resources Information Center

    Reish, Donald J.

    1978-01-01

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

  7. DIBUTYLPHTHALATE DEGRADATION IN ESTUARINE AND FRESHWATER SITES

    EPA Science Inventory

    Biotic and abiotic degradation of di-n-butylphthalate (DBP) in water and sediment/water systems from six different sites was investigated under laboratory conditions. Water and underlying sediment were collected from freshwater and estuarine sites in Florida, Mississippi, and Lou...

  8. AMBI indices and multivariate approach to assess the ecological health of Vellar-Coleroon estuarine system undergoing various human activities.

    PubMed

    Sigamani, Sivaraj; Perumal, Murugesan; Arumugam, Silambarasan; Preetha Mini Jose, H M; Veeraiyan, Bharathidasan

    2015-11-15

    Estuaries receive a considerable amount of pollutants from various sources. Presently an attempt has been made to assess whether the aquaculture discharges and dredging activities alter the ecological conditions of Vellar-Coleroon estuarine complex. The European Water Framework Directive (WFD) established a framework for the protection of marine waters. In this commission, a variety of indices were used, among them, AMBI (AZTI Marine Biotic Index) indices along with multivariate statistical approach is unique, to assess the ecological status by using macrobenthic communities. Keeping this in view, stations VE-1 and VE-4 in Vellar; CE-6 and CE-7 in Coleroon estuaries showed moderately disturbed with the AMBI values ranging between 3.45 and 3.72. The above said stations were situated near the shrimp farm discharge point and sites of dredging activities. The present study proves that various statistical and biotic indices have great potential in assessing the nature of the ecosystem undergoing various human pressures. PMID:26323865

  9. Integrating management tools and concepts to develop an estuarine planning support system: A case study of the Humber Estuary, Eastern England.

    PubMed

    Lonsdale, Jemma-Anne; Weston, Keith; Barnard, Steve; Boyes, Suzanne J; Elliott, Michael

    2015-11-15

    Estuaries are important because of their multiple uses and users which often makes them challenging to manage since management must strike a balance between the needs of users, the estuaries' ecological and economic value and the context of multiple legislative drivers. To facilitate management we have therefore developed an Estuarine Planning Support System (EPSS) framework using the Humber Estuary, Eastern England, as a case study which integrates the current legislation tools and concepts. This integrated EPSS framework is an improvement on previous approaches for assessing cumulative impacts as it takes into account legislative drivers, management tools and other mechanisms for controlling plans/projects specific to the estuary. It therefore enables managers and users to assess and address both the current state and the way in which a new industrial, port or urban development could impact an estuary in an accessible and understandable framework. PMID:26342391

  10. Draft genome sequence of Psychrobacter sp. ENNN9_III, a strain isolated from water in a polluted temperate estuarine system (Ria de Aveiro, Portugal).

    PubMed

    Gomes, Jaqueline Conceição Meireles; Azevedo, Juliana Simão Nina de; Veras, Adonney Allan de Oliveira; Alves, Jorianne Thyeska Castro; Henriques, Isabel; Correia, António; Silva, Artur Luiz da Costa da; Carneiro, Adriana Ribeiro

    2016-06-01

    The genus Psychrobacter includes Gram-negative coccobacilli that are non-pigmented, oxidase-positive, non-motile, psychrophilic or psychrotolerant, and halotolerant. Psychrobacter strain ENNN9_III was isolated from water in a polluted temperate estuarine system, contaminated with hydrocarbons and heavy metals. The genome has a G + C content of 42.7%, 2618 open reading frames (ORFs), three copies of the rRNAs operon, and 29 tRNA genes. Twenty-five sequences related to the degradation of aromatic compounds were predicted, as well as numerous genes related to resistance to metals or metal(loid)s. The genome sequence of Psychrobacter strain ENNN9_III provides the groundwork for further elucidation of the mechanisms of metal resistance and aromatic compounds degradation. Future studies are needed to confirm the usefulness of this strain for bioremediation proposes. PMID:27114904

  11. Evaluation of the organic matter sources using the δ13C composition of individual n-alkanes in sediments from Brazilian estuarine systems by GC/C/IRMS

    NASA Astrophysics Data System (ADS)

    Maioli, Otávio Luiz Gusso; de Oliveira, Cristiane Rossi; Dal Sasso, Marco Aurélio; Madureira, Luiz Augusto dos Santos; Azevedo, Débora de Almeida; de Aquino Neto, Francisco Radler

    2012-12-01

    The δ13C composition of individual n-alkanes (from C16 to C34) was measured from surface sediments of five Brazilian estuarine systems affected by different organic matter sources, such as harbor area, industries, urban centers and sugar cane crops, in order to determine the origins of the organic matter. The aliphatic hydrocarbon fraction was analyzed by gas chromatography-combustion-isotope ratio mass spectrometry (GC/C/IRMS). The levels of n-alkanes in the studied areas ranged from 0.34 to 18.14 μg kg-1, being relatively low in comparison to high polluted environments. The Carbon Preference Index (CPI) calculated in the C23-C34 range indicates that n-alkanes are mainly inherited from cuticular waxes of higher plants. The δ13C composition of all n-alkanes detected in the sediment samples ranged from -39.6 to -18.3‰ showing different sources for the studied estuarine systems. Through Principal Component Analysis (PCA) it was possible to verify the petrogenic influence in the n-alkane sources, especially in the Paraíba do Sul sediment samples. Differences up to 15‰ of the δ13C values between n-alkanes of odd and even carbon number (C26 and C27) also indicated mixture of petrogenic and biogenic sources in Paraíba do Sul River. High (less negative) δ13C n-alkane values of odd carbon number were obtained from two sampling sites located close to an ethanol plant, indicating residues discharge of sugar cane (C4 plant). Influence of C3 plants that are the main components of dense ombrophile forest was observed in the Itajaí-Açu sediments by the decrease of δ13C (about 10‰ compared to the Paraíba do Sul River δ13C).

  12. Remediation of Estuarine Barrages

    NASA Astrophysics Data System (ADS)

    Worrall, F.; Lamping, J.; Wright, J.

    2003-04-01

    Estuarine barrages have become a popular component of urban regeneration in the UK. However, a range of problems have been identified with the construction and operation of barrages, including: excess sediment build up; low oxygen conditions and eutrophication. This project has examined 3 strategies for the remediation of estuarine barrages: use of aerators; flushing of the impoundment by lock management; and use of boom/skirt technologies. The results show that: flushing of the barrage is ineffective; and that boom/skirt technologies could be successful in stratified impoundments. Aerators were shown to give significant increases in dissolved oxygen levels and field studies were able to delimit times when aeration would be effective. The study has shown that most problems experienced by the barrage are the result of inputs to the barrage rather than caused by the internal processes of the barrage itself and as such esturies must be managed as part of the catchment as a whole.

  13. Relating watershed nutrient loads to satellite derived estuarine water quality

    EPA Science Inventory

    Nutrient enhanced phytoplankton production is a cause of degraded estuarine water quality. Yet, relationships between watershed nutrient loads and the spatial and temporal scales of phytoplankton blooms and subsequent water quality impairments remain unquantified for most systems...

  14. Immigration and early life stages recruitment of the European flounder (Platichthys flesus) to an estuarine nursery: The influence of environmental factors

    NASA Astrophysics Data System (ADS)

    Amorim, Eva; Ramos, Sandra; Elliott, Michael; Bordalo, Adriano A.

    2016-01-01

    Connectivity between coastal spawning grounds and estuarine nurseries is a critical step in the life cycle of many fish species. Larval immigration and transport-associated physical-biological processes are determinants of recruitment success to nursery areas. The recruitment of the European flounder, Platichthys flesus, to estuarine nurseries located at the southern edge of the species distribution range, has been usually investigated during its juvenile stages, while estuarine recruitment during the earlier planktonic life stage remains largely unstudied. The present study investigated the patterns of flounder larval recruitment and the influence of environmental factors on the immigration of the early life stages to the Lima estuary (NW Portugal), integrating data on fish larvae and post-settlement individuals (< 50 mm length), collected over 7 years. Late-stage larvae arrived at the estuary between February and July and peak abundances were observed in April. Post-settlement individuals (< 50 mm) occurred later between April and October, whereas newly-settled ones (< 20 mm) were found only in May and June. Variables associated with the spawning, survival and growth of larvae in the ocean (sea surface temperature, chlorophyll a and inland hydrological variables) were the major drivers of flounder occurrence in the estuarine nursery. Although the adjacent coastal area is characterized by a current system with strong seasonality and mesoscale variability, we did not identify any influence of variables related with physical processes (currents and upwelling) on the occurrence of early life stages in the estuary. A wider knowledge on the influence of the coastal circulation variability and its associated effects upon ocean-estuarine connectivity is required to improve our understanding of the population dynamics of marine spawning fish that use estuarine nurseries.

  15. Variability of metal contents in the sea rush Juncus maritimus-estuarine sediment system through one year of plant's life.

    PubMed

    Almeida, C Marisa R; Mucha, Ana P; Vasconcelos, M Teresa S D

    2006-05-01

    Metal accumulation by Juncus maritimus and the effect this plant might have on the physico-chemical composition of sediments, from Douro river estuary (NW Portugal), were investigated through one year of plant's life. The contents of Al, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn were determined (by atomic absorption spectrophotometry) in sediments, rhizosediments (those among plant roots and rhizomes) and different tissues of J. maritimus. Two estuarine sites with different characteristics were studied, one a sandy sediment with relatively low organic matter content, the other a muddy site. The role of the plant seemed to be markedly dependent on the sediment composition. At the sandy site, significant variations throughout the year (a decrease from winter to summer and an increase in autumn) either in rhizosediment and sediment or in J. maritimus roots were only observed in Cd and Cu levels. These variations were the same in both compartments, probably caused by tidal water movements and the activity of the plant. At the muddy site, variations throughout the year were observed for all studied elements but Pb. Changes in the Cd and Zn contents of roots were opposite to those in the rhizosediment (uptake of Cd and Zn by J. maritimus roots in summer may have caused a decrease in rhizosediment levels). Fe and Mn showed similar patterns of variation in both roots and rhizosediment (contents significantly increasing in summer). Higher contents of Fe and Mn in roots in summer could be related to changes in mass, higher availability of the elements, or accumulation at the surface of the root in (hydr)oxides forms. For the remaining elements no significant correlations between rhizosediment and roots variations were observed, indicating that their uptake and release by roots were not based on single exchanges with the sediment. J. maritimus showed capacity to accumulate Cu, Zn and particularly Cd, thus appearing to be useful for the phytostabilization of these metals. PMID

  16. Estuarine fluvial floodplain formation in the Holocene Lower Tagus valley (Central Portugal) and implications for Quaternary fluvial system evolution

    NASA Astrophysics Data System (ADS)

    van der Schriek, Tim; Passmore, David G.; Rolão, Jose; Stevenson, Anthony C.

    2007-11-01

    We present a brief synthesis of the Quaternary fluvial record in the Lower Tagus Basin (central Portugal), concentrating on factors controlling infill and incision. The Holocene part of the record forms the focus of this paper and guides the questioning of the basic assumptions of the established Quaternary fluvial evolution model, in particular the link between sea-level change and fluvial incision-deposition. We suggest that several incision-aggradation phases may have occurred during glacial periods. Major aggradation events may overlap with cold episodes, while incision appears to concentrate on the warming limb of climate transitions. The complex stratigraphy of the Quaternary record in the Lower Tagus valley is influenced by repeated base-level and climate changes. This paper submits the first chronostratigraphic framework for valley fill deposits in the Lower Tagus area. Sea-level rise forced aggradation and controlled deposition of the fine-grained sedimentary wedge underlying the low-gradient Lower Tagus floodplain. Investigations have focused on the lower Muge tributary, where rapidly aggrading estuarine and fluvial environments were abruptly established (∼8150 cal BP) as sea level rose. Base level at the valley mouth controlled the upstream extent of the fine-grained backfill. Tidal environments disappeared abruptly (∼5800 cal BP) when the open estuary at the Muge confluence was infilled by the Tagus River. The decrease and final still stand of sea-level rise led to floodplain stabilisation with peat (∼6400-5200 cal BP) and soil formation (∼5200-2200 cal BP). Localised renewed sedimentation (∼2200-200 cal BP) is linked to human activity.

  17. Citizen participation and discontent in three Southern European health systems.

    PubMed

    Serapioni, Mauro; Matos, Ana Raquel

    2014-12-01

    Participation has featured in political agendas in recent decades and the domain of healthcare has not been indifferent to its appeal. Although emerging later than in other European regions, the involvement of civil society in healthcare decision-making procedures has proved one of the biggest challenges facing Southern European health systems. The health systems of the countries considered in this analysis - Italy, Portugal and Spain - underwent reforms that brought citizen participation to the forefront of the health system. Through national laws or health plans, each of these countries has recognised the need to promote participation in order to 'give a voice' to citizens in the health sector. Accordingly, a range of significant activities have been implemented in the region, although they have been developed unequally within national territories, at different paces and involving the mobilisation of different actors. This article focuses on the most relevant experiences of citizen participation designed and implemented in the three selected countries, describing their key features and potential, as well as the main critical issues and contradictions that have emerged over time. Particular emphasis is given to the impact of the current financial crisis on Southern European national health systems, especially in terms of participatory methods, the way in which citizen participation is progressing and civil society's reaction to these important changes. PMID:24947551

  18. Relative importance of estuarine flatfish nurseries along the Portuguese coast

    NASA Astrophysics Data System (ADS)

    Cabral, Henrique N.; Vasconcelos, Rita; Vinagre, Catarina; França, Susana; Fonseca, Vanessa; Maia, Anabela; Reis-Santos, Patrick; Lopes, Marta; Ruano, Miguel; Campos, Joana; Freitas, Vânia; Santos, Paulo T.; Costa, Maria José

    2007-02-01

    The relative importance of nursery areas and their relationships with several environmental variables were evaluated in nine estuarine systems along the Portuguese coast based on trawl surveys. Historical data were used to outline changes and trends in the nursery function of some of these estuaries over the past decades. The dominant flatfish species in Portuguese estuaries were Platichthys flesus (Linnaeus, 1758), Solea solea (Linnaeus, 1758), Solea senegalensis Kaup, 1858 and Monochirus hispidus Rafinesque, 1814, but their occurrence differed among the estuaries. P. flesus only occurred in estuaries north of the Tejo estuary (39°N), S. solea was quite rare along the southern Portuguese coast (south of 37°30'N), S. senegalensis occurred in estuaries throughout the coast, but its abundance varied considerably, and the occurrence of M. hispidus was limited to the Sado estuary and Ria Formosa. A Correspondence Analysis was performed to evaluate the relationships between flatfish species abundance and geomorphologic and hydrologic characteristics of estuaries (latitude, freshwater flow, estuarine area, intertidal area, mean depth and residence time). Abiotic characteristics (depth, temperature, salinity, sediment type) of nursery grounds of each flatfish species were also evaluated. Results showed that some estuaries along the Portuguese coast have nursery grounds used by several flatfish species (e.g. Ria de Aveiro, Sado estuary), while in other systems a segregation was noticed, with juveniles of different species occurring in distinct estuarine areas (e.g. Minho and Mondego estuaries). This emphasizes the relevance of niche overlap, but the potential for competition may be considerably minimized by differences in resource use patterns and by an extremely high abundance of resources. Peak densities of flatfishes recorded in nurseries areas along the Portuguese coast were within the range of values reported for other geographical areas. Inter-annual abundance

  19. Evidence for enhanced mercury reactivity in response to estuarine mixing

    NASA Astrophysics Data System (ADS)

    Rolfhus, Kristofer R.; Lamborg, Carl H.; Fitzgerald, William F.; Balcom, Prentiss H.

    2003-11-01

    Bioaccumulation of methylmercury in coastal U.S. fisheries has led to the issuance of numerous fish consumption advisories, and yet little is known about the processes that make Hg species chemically labile in coastal and estuarine systems. This study examined the role of estuarine mixing in formation of labile Hg complexes (reactive Hg) from relatively refractory Hg-organic associations in river water and characterized the behavior and distribution of Hg species in the Connecticut River estuary during three distinct collection periods. Results indicate that while total Hg partitioning and concentrations remained fairly constant with increasing salinity, the fraction present as reactive Hg concentrations increased, primarily in the particulate phase. Mixing experiments using both natural and prepared waters indicate that riverine organic ligands rapidly scavenge reactive Hg from natural waters on timescales of minutes to hours, while samples free of riverine influence remained much more "reactive." Modeling of the estuarine system suggests that elevated concentrations of chloride and dilution of the dominant organic ligand associated with estuarine mixing enhance reactive Hg and predict a bulk log formation constant for the binding ligand of approximately 21. Analysis of Hg0 production from Hg(II)-spiked, incubated estuarine samples supports the speciation data as higher reactive Hg concentrations and Hg0 production rates were observed in the more saline samples. These results suggest that estuarine mixing may exacerbate Hg methylation, evasion, and bioaccumulation in some systems by promoting the formation of Hg species that are readily labile.

  20. Evaluation of anthropic influences in an estuarine system of Southeastern Brazilian Coast by applying enrichment factors in cores from Bertioga Channel, Sao Paulo state

    NASA Astrophysics Data System (ADS)

    Figueira, R. C.; Sartoretto, J. R.; Salaroli, A. B.; Gabriela, C.; Andreza, R. P.; Tessler, M. G.; Mahiques, M.; Goncalves, C.

    2011-12-01

    Santos estuary, located in Southeastern Brazilian Coast, is impacted by several anthropic activities. The largest commercial harbor in South America and the main petrochemical and metallurgical industrial centre in the country, with approximately 1100 industries, are also in this estuary. The estuarine system has an important channel, called Bertioga Channel, which connects the upper Santos estuary to the ocean. In this channel are located the main mangroves of the estuarine complex that have a great potential of heavy metals retention. This behavior is related to sedimentary dynamics of system, where contaminated sediments from upper estuary are filtrated by channel before reaching the ocean. In this context, the main goal of this work was to carry out a study on toxic elements in cores from Bertioga Channel. Enrichment Factor (EF) was determined and it was related to geochronological data, allowing the evaluation of anthropic activities impact in this region. Thus, in February 2010, were collected five cores along the channel using a vibrocorer. The cores (150 - 220 cm) were sliced at every 2 cm, the samples were frozen and freeze-drying. Elemental preparation and analysis (As, Cd, Cr, Cu, Ni, Pb, Sc and Zn) followed SW-846 methodologies applying ICP-OES technique. Geocronology was determined via gamma spectrometry, by 210Pbxs and 137Cs methods. In order to assess the degree of sediment contamination, enrichment factors (EF) were calculated using Sc as normalization element Background values correspondeded to the element concentration in the bottom sediment core as determined by 210Pb chronology. EFs obtained in all analyzed cores were lower than 2, indicating a minimal pollution for the region. However, in core Bertioga 5 (the closest one to Santos harbor), it can be seen As, Cr, Pb and Zn enrichment from the bottom to the top, mainly from 70's, when harbor activities expanded. Despite of the low levels found for the studied elements, Bertioga channel area has

  1. Human effects on estuarine shoreline decadal evolution

    NASA Astrophysics Data System (ADS)

    Rilo, A.; Freire, P.; Ceia, R.; Mendes, R. N.; Catalão, J.; Taborda, R.

    2012-04-01

    Due to their sheltered conditions and natural resources, estuaries were always attractive to human activities (industrial, agriculture, residential and recreation). Consequently, the complex interactions between anthropogenic and natural drivers increase estuarine shoreline vulnerability to climate changes impacts. The environmental sustainability of these systems depends on a fragile balance between societal development and natural values that can be further disturbed by climate change effects. This challenging task for scientific community, managers and stakeholders can only be accomplished with interdisplinary approaches. In this context, it seems clear that estuarine management plans should incorporate the concept of change into the planning of policy decisions since these natural dynamic areas are often under human pressure and are recognized as sensitive to climate change effects. Therefore, the knowledge about historical evolution of estuarine shoreline is important to provide new insights on the spatial and temporal dimensions of estuarine change. This paper aims to present and discuss shoreline changes due to human intervention in Tagus estuary, located on the west coast of Portugal. Detailed margins cartography, in a 550m fringe (drawn inland from the highest astronomical tide line), was performed based on 2007 orthophotos (spatial resolution of 0.5 m) analysis. Several classification categories were considered, as urbanized areas, industrial, port and airport facilities, agriculture spaces, green areas and natural zones. The estuarine bed (area bellow the highest astronomical tide line) was also mapped (including human occupation, natural habitats, morpho-sedimentary units) based on the geographic information above and LANSAT 7 TM+ images using image processing techniques. Aerial photographs dated from 1944, 1946, 1948, 1955 and 1958 were analyzed for a set of pilot zones in order to fully understand the decadal shoreline change. Estuarine bed presents

  2. 230Th/232Th activity ratios as a chronological marker complementing 210Pb dating in an estuarine system affected by industrial releases.

    PubMed

    San Miguel, E G; Bolívar, J P; García-Tenorio, R; Martín, J E

    2001-01-01

    The main purpose of this research is to show the usefulness of the 230Th/232Th activity ratios as a chronological marker that can be helpful in the dating of sediment cores collected from an estuarine system located in the south west of Spain highly polluted by wastes from fertilizer plants. These wastes, being released for 30 years, and enriched in radionuclides from the uranium series including 210Pb, invalidate the application of the 210Pb dating technique in full extent to the sediment cores collected in this estuary. However, the evaluation and the interpretation of both 210Pb and 230Th/232Th profiles allows the determination of average sedimentation rates in different parts of the cores, contaminated and noncontaminated zone, that agree in the case analysed in this research. Through this approach, a confident chronology covering the last century, which is essential to analyse and reconstruct the historical evolution of other pollutants in this heavily contaminated system can be established. PMID:11291442

  3. Tidal influence on subtropical estuarine methane emissions

    NASA Astrophysics Data System (ADS)

    Sturm, Katrin; Grinham, Alistair; Werner, Ursula; Yuan, Zhiguo

    2014-05-01

    The relatively unstudied subtropical estuaries, particularly in the Southern Hemisphere, represent an important gap in our understanding of global greenhouse gas (GHG) emissions. These systems are likely to form an important component of GHG budgets as they occupy a relatively large surface area, over 38 000 km2 in Australia. Here, we present studies conducted in the Brisbane River estuary, a representative system within the subtropical region of Queensland, Australia. This is a highly modified system typical of 80% of Australia's estuaries. Generally, these systems have undergone channel deepening and straightening for safer shipping access and these modifications have resulted in large increases in tidal reach. The Brisbane River estuary's natural tidal reach was 16 km and this is now 85 km and tidal currents influence double the surface area (9 km2 to 18 km2) in this system. Field studies were undertaken to improve understanding of the driving factors behind methane water-air fluxes. Water-air fluxes in estuaries are usually calculated with the gas exchange coefficient (k) for currents and wind as well as the concentration difference across the water-air interface. Tidal studies in the lower and middle reaches of the estuary were performed to monitor the influence of the tidal stage (a proxy for kcurrent) on methane fluxes. Results for both investigated reaches showed significantly higher methane fluxes during the transition time of tides, the time of greatest tidal currents, than during slack tide periods. At these tidal transition times with highest methane chamber fluxes, lowest methane surface water concentrations were monitored. Modelled fluxes using only wind speed (kwind) were at least one order of magnitude lower than observed from floating chambers, demonstrating that current speed was likely the driving factor of water-air fluxes. An additional study was then conducted sampling the lower, middle and upper reaches during a tidal transition period

  4. Our Southern Neighbors - 2000 Nearby Red Dwarf Systems

    NASA Astrophysics Data System (ADS)

    Winters, Jennifer G.; Hosey, A. D.; Lurie, J. C.; Hambly, N.; Henry, T. J.; Jao, W.; Riedel, A. R.; Subasavage, J.

    2013-01-01

    Distance determinations to nearby objects are vitally important, as our solar neighbors set the standards for the primary rung in the cosmic distance ladder. The optimal tool for accomplishing this seemingly simple task is trigonometric parallax. Measuring parallaxes is very time-intensive, however. Photometric distance estimates can be useful in deciding which are the best targets for the limited slots available in traditional parallax programs. Photometry also reveals stars that do not fall neatly onto the main sequence, such as young stars, unresolved multiples, and subdwarfs, once an accurate trigonometric parallax has been measured. We present photometry and distances for more than 2000 southern M dwarf systems thought to be near the Sun, broken into three distinct samples. The first includes ~500 systems with accurate trigonometric parallaxes placing them within 25 pc --- ~150 have been published as a result of the RECONS astrometry program at the CTIO 0.9m telescope, which we now operate for NOAO. For an additional ~700 systems, we use VRI measurements from our photometry program (also at the 0.9m) with 2MASS JHK photometry to estimate distances accurate to 15%. Roughly one third of these systems are on our parallax program. The third sample includes ~1000 more systems for which plate BRI photometry from SuperCOSMOS is combined with JHK to provide distances accurate to 26%. Together, these three sets of stars comprise a list of ~2100 red dwarf systems within 25 pc in the southern sky. These stars are crucial to our understanding of the stellar luminosity and mass functions in the Milky Way and beyond, and provide ideal targets for planets searches using a variety of techniques. This effort is supported by the NSF through grants AST-0908402 and AST-1109445, and via observations made possible by the SMARTS Consortium.

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

    NASA Astrophysics Data System (ADS)

    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

  6. Molecular characterization of Pseudo-nitzschia community structure and species ecology in a hydrographically complex estuarine system (Puget Sound, Washington, USA)

    PubMed Central

    Hubbard, Katherine A.; Olson, Claire H.; Armbrust, E. Virginia

    2015-01-01

    Species within the toxic marine diatom genus Pseudo-nitzschia coexist in coastal and estuarine waters globally and are difficult to distinguish by microscopy. Here, we describe a sensitive, high throughput PCR-based Automated Ribosomal Intergenic Spacer Analysis (ARISA) approach to determine the relative abundance of Pseudo-nitzschia species within natural communities over space and time. The method was quantitatively validated using simplified mixtures of DNA or ITS1 standards from isolates of P. pungens, P. multiseries, and P. delicatissima. Relative abundance calculations based on ARISA profiles from these mixtures reflected input ratios, with minor deviations resulting from intraspecific variability. ARISA was used to identify and quantify at least eight species within Puget Sound and the eastern Strait of Juan de Fuca, Washington, USA: P. americana, P. australis/P. seriata, P. cuspidata, P. delicatissima, P. fraudulenta, P. fryxelliana, P. multiseries, and P. pungens; genotypes corresponding to P. pungens var. pungens and P. pungens var. cingulata were identified by environmental sequencing. The different species were significantly correlated with physical (temperature, salinity), biological (chlorophyll a fluorescence, oxygen), and/or chemical (ammonium, nutrient ratios) factors. The ability to determine shifts in the relative abundance of Pseudo-nitzschia species over spatial and temporal scales relevant to dispersion and selection facilitates dissection of the varied mechanisms driving vertical and horizontal species distribution patterns in hydrographically complex systems. PMID:27239082

  7. Southern Africa Validation of NASA's Earth Observing System (SAVE EOS)

    NASA Technical Reports Server (NTRS)

    Privette, Jeffrey L.

    2000-01-01

    Southern Africa Validation of EOS (SAVE) is 4-year, multidisciplinary effort to validate operational and experimental products from Terra-the flagship satellite of NASA's Earth Observing System (EOS). At test sites from Zambia to South Africa, we are measuring soil, vegetation and atmospheric parameters over a range of ecosystems for comparison with products from Terra, Landsat 7, AVHRR and SeaWiFS. The data are also employed to parameterize and improve vegetation process models. Fixed-point and mobile "transect" sampling are used to collect the ground data. These are extrapolated over larger areas with fine-resolution multispectral imagery. We describe the sites, infrastructure, and measurement strategies developed underSAVE, as well as initial results from our participation in the first Intensive Field Campaign of SAFARI 2000. We also describe SAVE's role in the Kalahari Transect Campaign (February/March 2000) in Zambia and Botswana.

  8. Hydrodynamic behavior of the Cape Fear River and estuarine system: A synthesis and observational investigation of discharge-salinity intrusion relationships

    NASA Astrophysics Data System (ADS)

    Becker, May Ling; Luettich, Richard A., Jr.; Mallin, Michael A.

    2010-07-01

    Transport of constituents in partially mixed estuaries depends on the relative strengths of dominant forcing mechanisms which may include tides, river input, and wind. In this study, we investigated the major physical mechanisms that influence the salinity structure in the Cape Fear River Estuary (CFRE), a partially mixed estuary that is representative of river-dominated estuaries along the southeast Atlantic coast of the U.S. Based on analysis of observed hydrographic and hydrodynamic data, we first describe differences in velocity, salinity, and stratification at along-channel sections of the estuary for relatively low-flow conditions. We then investigate the influence of river inflow on the salinity intrusion (defined by the 1-salinity contour near the bottom), based on six methods of choosing discharge in order to identify an appropriate means of incorporating flow history into the discharge value. Our analyses indicate: 1) 92 percent of the variability in the length of the salinity intrusion over a five-year period can be explained based on the Hydrologic Flood Method identified in this work, 2) the salinity intrusion depends more weakly on discharge than predicted by classic analytical relationships for exchange-dominated systems in which the intrusion varies with discharge to the power of (-1/3), and 3) intra-tidal and tidal-range differences based on a 29-day modulation significantly influence the salinity structure. Our results suggest that the salinity intrusion location is dependent upon the hydrologic "flood," defined by a peak in the river-discharge hydrograph. The analysis indicates that the new method used to determine discharge in the CFRE can more accurately explain river inflow-salinity relationships than previously investigated methods. In river-estuary systems in which hydrologic flood peaks are large relative to base flow, we hypothesize the hydrologic flood model offers a useful tool for predicting the estuarine salinity response to river

  9. Properties of light absorption in a highly coloured estuarine system in south-east Australia which is prone to blooms of the toxic dinoflagellate Gymnodinium catenatum

    NASA Astrophysics Data System (ADS)

    Clementson, Lesley A.; Parslow, John S.; Turnbull, Alison R.; Bonham, Pru I.

    2004-05-01

    The Huon Estuary in south-east Tasmania is an important site in Australia's aquaculture and finfish industries. Atlantic salmon and shellfish are farmed in the Huon River Estuary, which drains a catchment that includes both areas of pristine wilderness and agriculture. The estuary experiences algal blooms, including blooms of the toxic dinoflagellate Gymnodinium catenatum, which can cause considerable problems for the aquaculture industry. The freshwater input is highly coloured due to high levels of humic material and this combined with intrusions of clearer oceanic water and the occurrence of algal blooms makes this estuary optically complex. Between November 1996 and September 1998 samples for pigment and optical analyses were collected weekly from five sites within the mid to lower regions of the estuary. In addition, every three months (beginning July 1996), samples were collected from 30 sites within the full river/estuary system. Early in December 1997 a bloom of Gymnodinium catenatum occurred throughout the estuary and persisted until June 1998. Chromophoric dissolved organic matter (CDOM) was found to dominate the total absorption of the water throughout the entire estuary and over the two-year duration of the study. The occurrence of algal blooms showed no correlation with the optical characteristics of the estuary, suggesting that optical parameters cannot be used to predict the occurrence of algal blooms in this estuary. Blooms of different algal species, such as diatoms and dinoflagellates, may be able to be distinguished by their absorption spectra in the UV region rather than the visible region. To date, this study is the most detailed spatial and temporal study of the characteristics of light absorption in an estuarine system within Australia.

  10. pp iii The importance of high-resolution monitoring in erosion and deposition dynamics studies: examples from estuarine and fluvial systems

    NASA Astrophysics Data System (ADS)

    Lawler, D. M.

    2005-01-01

    Erosion and deposition processes lie at the centre of geomorphological explanation, but progress in understanding has been limited by a lack of appropriate high-resolution monitoring methodologies which permit detection of erosion and deposition dynamics. This paper presents a case for monitoring erosion and deposition at high temporal resolutions, and uses hypothetical approaches supported by example erosion and deposition events and analyses drawn from estuarine and fluvial systems. The paper first presents testable hypotheses to demonstrate the complexity of possible event combinations, sequences and juxtapositions for the erosion driving forces which underpin the need for high-resolution monitoring. Second, it summarises recent improvements to the Photo-Electronic Erosion Pin (PEEP) automatic erosion and deposition monitoring system, including the novel concept of Thermal Consonance Timing (TCT), which is particularly promising because it helps to define the timing of nocturnal events and through the entire hydrograph. Third, example results are discussed from high-resolution monitoring of bank erosion at a tidal site at Burringham on the River Trent in northern England. Tidal banks are revealed to be much more dynamic than previous conventional monitoring has indicated. A key result is that, because the high-resolution approach allows erosional and depositional activity to be assigned to specific periods of tidal inundation, it becomes possible for the first time routinely to produce 'event-based' erosion (36 mm h -1) and deposition rates (4.5 and 8.4 mm h -1). Such rate determinations are potentially very useful in the field validation of sedimentological and geomorphological models, including grain settling and resuspension theory. Fourth, through a longer term of aggregated daily data, a striking 2-week cycle of deposition and erosion emerges which correlates most strongly with spring-neap tidal cycling, but is moderated by wind stress effects. Sediment was

  11. Geodynamics of flat-slab subduction, sedimentary basin development, and hydrocarbon systems along the southern Alaska convergent plate margin

    NASA Astrophysics Data System (ADS)

    Finzel, Emily S.

    Combining field-based geologic studies and numerical modeling provides a robust tool for evaluating the geodynamics of convergent margins. Southern Alaska is arguably the most tectonically active part of the convergent margin of western North America. This conceptual approach has been used to interpret the modern basin dynamics, as well as key stages in the Cenozoic development of this region, including spreading-ridge and flat-slab subduction. New macrofossil, palynological, and lithostratigraphic data for the Bear Lake Formation in the Bristol Bay retroarc basin allow us to construct the first chronostratigraphic framework for this formation, and indicate deposition during Middle and Late Miocene time in a regional transgressive estuarine depositional system. In the Cook Inlet forearc basin, new detrital zircon U-Pb geochronology, rare earth element geochemistry, and clast compositional data from middle Eocene-Pliocene strata demonstrate the importance of sediment sources located in the retroarc region and along strike within the basin. The Yakutat microplate has recently been reinterpreted to represent buoyant crust that is presently subducting at a shallow angle beneath southern Alaska. Integration of stratigraphic, geochronologic, and thermochronologic data indicate that in the flat-slab region, exhumation initiated ca. 43 Ma and migrated inboard, magmatism ceased at ca. 32 Ma, and deposition in sedimentary basins ended by ca. 23 Ma. Sedimentary basins positioned along the western and northern perimeter of the flat-slab region record enhanced subsidence and sediment delivery from the flat-slab region beginning in late Oligocene and middle Miocene time respectively. The discrete contributions of unique driving forces for lithospheric deformation in western Canada and Alaska have not been quantified in detail, so their relative role in influencing deformation has remained unresolved. Using finite element models, we calculate a continuous strain rate and velocity

  12. Habitat- and bay-scale connectivity of sympatric fishes in an estuarine nursery

    NASA Astrophysics Data System (ADS)

    Dance, Michael A.; Rooker, Jay R.

    2015-12-01

    Acoustic telemetry was used to examine habitat- and bay-scale connectivity for co-occurring juvenile fishes, southern flounder (Paralichthys lethostigma) and red drum (Sciaenops ocellatus), at two spatial scales in a model estuarine seascape. An acoustic positioning system was deployed to examine habitat-scale (ca. 1 m-1 km) movement, while a larger gridded array was deployed to examine bay-scale movement (ca. 1-20 km). Both species exhibited greater use of edge habitat and seagrass beds at the habitat scale; however, rates of movement within habitats varied between species. Southern flounder movement (mean = 4.0 m min-1) increased with decreasing habitat complexity (seagrass to bare sand) and increasing temperature, while red drum rate of movement (mean = 8.4 m min-1) was not significantly affected by environmental factors at the habitat scale, indicating the use of different foraging strategies (i.e. ambush vs. active). Bay-scale distribution was influenced by physicochemical conditions and seascape composition, with both species found most frequently in areas with high seagrass coverage and relative close proximity to tidal creeks and connective channels. Response to environmental variables often differed between species and the probability of bay-scale movement (>1 km) for southern flounder was greatest on days with narrow tidal ranges (<0.4 m) and higher temperatures (>17 °C), while the probability of bay-scale movement for red drum increased in response to decreasing salinity and lower temperatures (<16 °C). Species-specific variation in movement patterns within and across habitat types observed here at both the habitat and bay scale suggest sympatric species employ different strategies to partition resources within estuarine nursery areas and highlight the importance of multi-species assessments for improving our understanding of habitat value and ecosystem function.

  13. Variability of Southern Valu Fa Ridge Magmatic Systems

    NASA Astrophysics Data System (ADS)

    Goddard, C. I.; Christie, D. M.; Arculus, R.

    2004-12-01

    Valu Fa Ridge (VFR), which encompasses the southernmost segments of the East Lau Spreading Center (ELSC), is an important end-member in the spectrum of back-arc spreading centers because it is strongly affected in all aspects of the spreading process by inputs from the nearby active Tofua (Tonga) volcanic arc, and because its magma systems are rapidly evolving as the VFR propagates to the south. New lava samples collected by the TELVE Expedition of the R/V Southern Surveyor (Australia) from the four southernmost VFR segments have greatly increased the number and spatial distribution of fresh volcanic glass samples, quadrupling the availability of "primitive" (MgO > 6 wt.%) glass samples and encompassing significant along- and across-axis geochemical variability. These new data provide an opportunity to evaluate both the evolution of crustal magmatic processes relative to southward rift propagation and variability in mantle source inputs relative to the active volcanic arc. The four sampled segments of VFR are separated by left-stepping overlapping offsets that differ from their mid-ocean ridge counterparts in their longer, more parallel overlapping limbs and in the absence of an overlap basin. The TELVE glasses display considerable major element variability and the VFR is unusual among well-developed spreading centers in its strongly bimodal volcanism, in the abundance of evolved lavas and in the coexistence of two distinct liquid lines of descent. Dacites and rhyolites (SiO2 ~67-75 wt.%) are relatively abundant close to segment ends or discontinuities along the southernmost three ridge segments, but rare from the northernmost sampled segment and from off-axis seamounts. A "Daly Gap" from ~60-67 wt.% SiO2 and 1.75-0.75 wt.% MgO is present along the northern segments but absent near the southern propagating rift tip. Primitive (MgO > 6wt.%) glasses were recovered from all VFR segments and on 5 of the 9 sampled seamounts. Both high-silica glasses and FeTi basalt

  14. Cumulative Impact of Marinas on Estuarine Water Quality

    PubMed

    McAllister; Overton; Brill

    1996-05-01

    The purpose of this work is to present a modeling approach for assessing and managing the cumulative impact of marinas on estuarine systems. In doing so, both a water-quality model and a planning and management model are developed. The water-quality model predicts biochemical oxygen demand (BOD) and fecal coliform (FC) loadings from marina sources in a hypothetical North Carolina estuary. By running the water-quality model repeatedly with varied loading input, impact coefficients are determined. These impact coefficients are used in the planning and management model, the output of which gives the sizes and locations of marinas in the estuarine system such that dissolved oxygen (DO) and FC water-quality standards are maintained.Five different estuarine development scenarios are considered. Each scenario is evaluated with respect to both maximum and uniform land development constraints. In addition, two alternative fecal coliform standards are used with each of the development options. PMID:8661609

  15. Environmental availability of potentially toxic elements in estuarine sediments of the Cananéia-Iguape coastal system, Southeastern Brazil.

    PubMed

    Tramonte, Keila Modesto; Figueira, Rubens Cesar Lopes; de Lima Ferreira, Paulo Alves; Ribeiro, Andreza Portella; Batista, Miriam Fernanda; de Mahiques, Michel Michaelovitch

    2016-02-15

    The Cananéia-Iguape system is located in a Southeastern Brazilian coastal region, acknowledged by UNESCO as Biosphere Reserve of the Atlantic Rainforest. This system underwent important environmental changes due to the opening of the artificial channel of Valo Grande and by past intensive Pb ore mining activities. In view of this scenario, this study evaluated Cu, Pb and Zn availability in sediments from Cananéia-Iguape system, based on the content associated with the main components of the sediments. Moreover, in order to assess local contamination, the metals' contents were compared to Canadian quality guidelines, the past levels of metals preceding the mining activities and background sediment values. Concerning Cu and Zn in a state of chemical remobilization, both elements would possibly present no harm to the local communities. However, Pb available content exceeded the comparison values in various sampling sites, suggesting the need of monitoring regarding its bioavailability. PMID:26707887

  16. 11. 'Southern Pacific Company Pacific System. 1 180'1/4' ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. 'Southern Pacific Company - Pacific System. 1 - 180'-1/4' c. to c. End Pins S. Tr. Thro. Span. 16th crossing Sacramento River, The Phoenix Bridge Co., Phoenixville, Pa., Apr. 25th 1901.' - Southern Pacific Railroad Shasta Route, Bridge No. 324.99, Milepost 324.99, Shasta Springs, Siskiyou County, CA

  17. Impact of biodiversity-climate futures on primary production and metabolism in a model benthic estuarine system

    PubMed Central

    2011-01-01

    Background Understanding the effects of anthropogenically-driven changes in global temperature, atmospheric carbon dioxide and biodiversity on the functionality of marine ecosystems is crucial for predicting and managing the associated impacts. Coastal ecosystems are important sources of carbon (primary production) to shelf waters and play a vital role in global nutrient cycling. These systems are especially vulnerable to the effects of human activities and will be the first areas impacted by rising sea levels. Within these coastal ecosystems, microalgal assemblages (microphytobenthos: MPB) are vital for autochthonous carbon fixation. The level of in situ production by MPB mediates the net carbon cycling of transitional ecosystems between net heterotrophic or autotrophic metabolism. In this study, we examine the interactive effects of elevated atmospheric CO2 concentrations (370, 600, and 1000 ppmv), temperature (6°C, 12°C, and 18°C) and invertebrate biodiversity on MPB biomass in experimental systems. We assembled communities of three common grazing invertebrates (Hydrobia ulvae, Corophium volutator and Hediste diversicolor) in monoculture and in all possible multispecies combinations. This experimental design specifically addresses interactions between the selected climate change variables and any ecological consequences caused by changes in species composition or richness. Results The effects of elevated CO2 concentration, temperature and invertebrate diversity were not additive, rather they interacted to determine MPB biomass, and overall this effect was negative. Diversity effects were underpinned by strong species composition effects, illustrating the importance of individual species identity. Conclusions Overall, our findings suggest that in natural systems, the complex interactions between changing environmental conditions and any associated changes in invertebrate assemblage structure are likely to reduce MPB biomass. Furthermore, these effects would be

  18. The influence of wind and tidal forcing on sediment resuspension and transport in a large, shallow estuarine system

    NASA Astrophysics Data System (ADS)

    Clunies, G.; Mulligan, R. P.; Mallinson, D. J.; Walsh, J. P.

    2012-12-01

    Eastern North Carolina is characterized by a large system of interconnected estuaries, including Pamlico Sound, that are bordered on the east side by 260 km of barrier islands punctuated by several tidal inlets. The sound is characterized by a mean water depth of 5 m and muddy to sandy sediments. Wind forcing primarily controls the hydrodynamics of the sound, except near inlets where tides are more influential. The quantity and size of tidal inlets has a large effect on salinity levels, circulation, and bathymetry within the sound. The Delft3D model, validated using field observations at two sites, was used to estimate the contributions of wind and tidal forcing to flow velocities, bed shear stresses and sediment resuspension and sediment transport. Results are presented to determine the ability of the numerical model to accurately simulate the morphological changes in Pamlico Sound in response to major storm events. Previous storm events have caused significant barrier overstepping causing extensive damage to barrier island infrastructure and forcing the surrounding system to shift to a new dynamic equilibrium when left unaltered. Model results allow us to further enhance our understanding of the interdependent hydrodynamic and sediment processes in the system. In combination with sediment cores and geophysical surveys, this work will aid in reconstructing the evolution of the morphology of Pamlico Sound over the Holocene and estimate the sedimentary response to major storm events that shaped the basin.

  19. Estuarine 'collaboratories:' regional and global perspectives (Invited)

    NASA Astrophysics Data System (ADS)

    Baptista, A. M.; Needoba, J. A.; Davis, M.; Leinen, M.

    2013-12-01

    There is an urgent need to anticipate and manage environmental changes in estuaries, as these critical ecosystems provide services that are essential for regional and global sustainability. Collaboratively designed and operated estuarine observation and prediction systems are progressively enabling long-term and high-resolution characterizations of estuarine variability and function, thus providing a powerful foundation for stewardship activities. The benefits of these 'collaboratories' have been demonstrated regionally in various estuaries, and their broader scale potential is being explored through an emerging national and international initiative. The first part of this presentation will address the lessons learned from SATURN (http://www.stccmop.org), a mature multi-institutional 'collaboratory' for the Columbia River estuary. SATURN innovatively integrates sensors, models, flows of information, and communities of practice. This integration has fueled advances in understanding and prediction of the estuary as a complex and highly variable bioreactor, subject to shifts from global climate change and from evolving regional uses. Our focus will be on describing the aspects of the design and practice that make SATURN transformative as a scientific and management-support tool at a regional scale. The second part of the presentation will address the translation of lessons learned from and beyond SATURN into requirements for a global network of estuarine observation and prediction systems. 'Our Global Estuary' is an initiative designed to create and use such a network, to maximize the aggregate potential of estuaries as sentinels and key players in global sustainability. We will report on the main recommendations of the first planning workshop for this initiative, which will take place on October 2013.

  20. Remote sensing of estuarine fronts and their effects on pollutants

    NASA Technical Reports Server (NTRS)

    Klemas, V. (Principal Investigator); Polis, D. F.

    1975-01-01

    The author has identified the following significant results. Imagery from LANDSAT 1 and 2 proved valuable in determining the location, type, and extent of estuarine fronts under different tidal conditions. Neither ships nor aircraft alone could provide as complete, synoptic, and repetitive an overview as did the satellites. Since estuarine fronts influence the movement of oil slicks and dispersion of other pollutants, cleanup operations depending on real time use of oil slick movement prediction models will benefit not only from aircraft tracking the actual slicks but also from real time satellite observations of surface currents and the location of frontal systems.

  1. Holocene paleoclimate records from a large California estuarine system and its watershed region: linking watershed climate and bay conditions

    NASA Astrophysics Data System (ADS)

    Malamud-Roam, Frances P.; Lynn Ingram, B.; Hughes, Malcolm; Florsheim, Joan L.

    2006-07-01

    The San Francisco Bay-Delta system includes a watershed that covers a large area of California and provides water to two-thirds of the State's population. Climate over the estuary and its watershed in the dry summer months is controlled by the subtropical high which dominates and deflects storms from California. The subtropical high weakens and migrates south as the Aleutian Low strengthens, bringing wet winter storms to the region. Paleoclimatic records from the Bay and its greater watershed, spanning the Holocene, are reviewed here in order to better understand natural variations of precipitation and runoff and the linkages between those variations and the salinity and ecosystems of the estuary. To better understand regional-scale climate patterns, paleoclimate records from coastal California and the Great Basin are also considered. Large fluctuations in climate have occurred during the period of interest, and there is generally good agreement between the paleoclimate records from different regions. Early Holocene climate throughout California was marked by rising temperatures and reduced moisture as seen in fire records from the watershed. This warmth and aridity peaked about 5000-7000 years ago and was followed by a cooling trend, with variable moisture conditions. The Estuary formed relatively rapidly in response to a high rate of sea level rise that dominated the Holocene until about 6000 years ago, and the subsequent reduced rate of inundation allowed vast tidal marshes to form along the edges of the estuary, which have since been recording changes in environmental conditions. The impacts of changing regional climate patterns are experienced in the San Francisco Bay-Delta system, as altered fresh water flows result in altered estuary salinity. For example, approximately 3800 cal yr B.P., records from throughout the state indicate a cool, moist period, and Bay salinity was reduced; this period was followed by a general drying trend throughout California over

  2. Stable carbon and nitrogen isotope composition of aquatic and terrestrial plants of the San Francisco Bay estuarine system

    USGS Publications Warehouse

    Cloern, J.E.; Canuel, E.A.; Harris, D.

    2002-01-01

    We report measurements of seasonal variability in the C-N stable isotope ratios of plants collected across the habitat mosaic of San Francisco Bay, its marshes, and its tributary river system. Analyses of 868 plant samples were binned into 10 groups (e.g., terrestrial riparian, freshwater phytoplankton, salt marsh) to determine whether C-N isotopes can be used as biomarkers for tracing the origins of organic matter in this river-marsh-estuary complex. Variability of ??13C and ??15N was high (???5-10???) within each plant group, and we identified three modes of variability: (1) between species and their microhabitats, (2) over annual cycles of plant growth and senescence, and (3) between living and decomposing biomass. These modes of within-group variability obscure any source-specific isotopic signatures, confounding the application of C-N isotopes for identifying the origins of organic matter. A second confounding factor was large dissimilarity between the ??13C-??15N of primary producers and the organic-matter pools in the seston and sediments. Both confounding factors impede the application of C-N isotopes to reveal the food supply to primary consumers in ecosystems supporting diverse autotrophs and where the isotopic composition of organic matter has been transformed and become distinct from that of its parent plant sources. Our results support the advice of others: variability of C-N stable isotopes within all organic-matter pools is high and must be considered in applications of these isotopes to trace trophic linkages from primary producers to primary consumers. Isotope-based approaches are perhaps most powerful when used to complement other tools, such as molecular biomarkers, bioassays, direct measures of production, and compilations of organic-matter budgets.

  3. Challenging paradigms in estuarine ecology and management

    NASA Astrophysics Data System (ADS)

    Elliott, M.; Whitfield, A. K.

    2011-10-01

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

  4. Resolving drivers of variability in estuarine metabolism from sustained observations of water quality in the SE US

    EPA Science Inventory

    We examine trends in water quality in long-term monitoring (10-15 y) data collected at 5 estuarine systems of NOAA’s National Estuarine Research Reserve System: Grand Bay, MS; Weeks Bay, AL; Apalachicola Bay, FL; Rookery Bay, FL, and Guana Tolomatos and Matanzas Rivers, FL. These...

  5. Microbial Community in the Hydrothermal System at Southern Mariana Trough

    NASA Astrophysics Data System (ADS)

    Kato, S.; Itahashi, S.; Kakegawa, T.; Utsumi, M.; Maruyama, A.; Ishibashi, J.; Marumo, K.; Urabe, T.; Yamagishi, A.

    2004-12-01

    There is unique ecosystem around deep-sea hydrothermal area. Living organisms are supported by chemical free energy provided by the hydrothermal water. The ecosystem is expected to be similar to those in early stage of life history on the earth, when photosynthetic organisms have not emerged. In this study, we have analyzed the microbial diversity in the hydrothermal area at southern Mariana trough. In the "Archaean Park Project" supported by special Coordination Fund, four holes were bored and cased by titanium pipes near hydrothermal vents in the southern Mariana trough in 2004. Hydrothermal fluids were collected from these cased holes and natural vents in this area. Microbial cells were collected by filtering the hydrothermal fluid in situ or in the mother sip. Filters were stored at -80C and used for DNA extraction. Chimneys at this area was also collected and stored at -80C. The filters and chimney samples were crushed and DNA was extracted. DNA samples were used for amplification of 16S rDNA fragments by PCR using archaea specific primers and universal primers. The PCR fragments were cloned and sequenced. These PCR clones of different samples will be compared. We will extend our knowledge about microbiological diversity at Southern Mariana trough to compare the results obtained at other area.

  6. Estuarine versus transient flow regimes in Juan de Fuca Strait

    NASA Astrophysics Data System (ADS)

    Thomson, Richard E.; MiháLy, Steven F.; Kulikov, Evgueni A.

    2007-09-01

    Residual currents in Juan de Fuca Strait are observed to switch between two fundamental states: estuarine and transient. The estuarine regime, which prevails roughly 90% of the time in summer and 55% of the time in winter, has a fortnightly modulated, three-layer structure characterized by strong (˜50 cm s-1) outflow above 60 ± 15 m depth, moderate (˜25 cm s-1) inflow between 60 and 125 m depth, and weak (˜10 cm s-1) inflow below 125 ± 10 m depth. Rotation increases the upper layer depth by 40 m on the northern side of the channel and upwelling-favorable coastal winds augment inflow in the bottom layer by as much as 5 cm s-1. Rotation, combined with modulation of the estuarine currents by tidal mixing in the eastern strait, leads to fortnightly variability in the along-channel velocity and cross-channel positioning of the core flow regions. Transient flows, which occur roughly 10% of the time in summer and 45% of the time in winter, are rapidly evolving, horizontally and vertically sheared "reversals" in the estuarine circulation generated during poleward wind events along the outer coast. Major events can persist for several weeks, force a net inward transport, and give rise to an O(10) km wide, surface-intensified, O(100) cm s-1 inflow along the southern (Olympic Peninsula) boundary of the strait. This "Olympic Peninsula Countercurrent" is typically accompanied by an abrupt decrease in salinity, indicating that it is a buoyancy flow originating with low-density water on the northern Washington shelf.

  7. Ecological periodic tables for nekton and benthic macrofaunal community usage of estuarine habitats Slides

    EPA Science Inventory

    Ecological periodic tables for nekton and benthic macrofaunal community usage of estuarine habitats Steven P. Ferraro, U.S. Environmental Protection Agency, Newport, OR Background/Questions/Methods The chemical periodic table, the Linnaean system of classification, and the Her...

  8. A CONCEPTUAL MODEL FOR MULTI-SCALAR ASSESSMENTS OF ESTUARINE ECOLOGICAL INTEGRITY

    EPA Science Inventory

    A conceptual model was developed that relates an estuarine system's anthropogenic inputs to it's ecological integrity. Ecological integrity is operationally defined as an emergent property of an ecosystem that exists when the structural components are complete and the functional ...

  9. 17. 'Southern Pacific Company Pacific System, 3 180'61/2' ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    17. 'Southern Pacific Company - Pacific System, 3 - 180'-6-1/2' c. to c. end pins S. Tr. Thro. Spans, 10th, 11th and 13th Crossings of Sacramento River, also for 1 - 180'-6-1/2' c. to c. end pins S. Tr. Thro. Span, 8th Crossing Sacramento River, The Phoenixville Bridge Co., Phoenixville Pa., Apr. 9th, 1901.' - Southern Pacific Railroad Shasta Route, Bridge No. 310.58, Milepost 310.58, Sims, Shasta County, CA

  10. Contribution of intra-estuarine tributaries to estuarine sediment budget

    NASA Astrophysics Data System (ADS)

    Lemoine, M.; Deloffre, J.; Lafite, R.; Le Hir, P.; Oberle, K.; Petit, F.

    2012-04-01

    This study aims to quantify the sedimentary fluxes between the Seine estuary and an intra-estuarine tributary: the Risle river, located close to the Seine turbidity maximum (TM). Four key areas are monitored from the upstream river to the confluence. Water level, current speed, Suspended Solid Concentration (SSC) and salinity are continuously monitored at high-frequency during one hydrological cycle. This dataset allows to (i) identify the hydrodynamics and sedimentary forcing parameters including their spatial and temporal variability (from event to seasonal scale) and (ii) establish the sedimentary fluxes. It appears that the Risle river behaviour is similar to a macrotidal estuary. The hydrodynamics in the upstream part is mainly controlled by the river discharge that reflects the watershed inputs. The sedimentary fluxes are thus also controlled by the discharge in the order of 25,000 tons.years-1. In the downstream part, the tide is the main hydrodynamics forcing parameter (maximum current speed ~ 2.5m.s-1). The intertidal mudflats (44,000m2), only localised in this part, are subjected to erosion (10,000 tons.years-1). Erosion process is generally sudden and intense, with destabilization and removal of pluri-metric muddy blocks. This area is also characterized by the presence of a TM whom resuspended volume ranges between 5,000 tons (neap tide) and 25,000 tons (spring tide) which represents between 2 and 10 % of the Seine TM volume. During ebb, the Risle river plume contributes to locally increase the SSC in the Seine estuary, while during flood, particules from the Seine estuary are trapped in the river. Thus, exchanges between the Seine TM and a tributary located near this sedimentary stock are significant. This study was conducted during a period of low discharge with low intensity flood. In the Seine estuary, the TM average position is partially controlled by pluri-annual cycles. Besides this phenomenon is poorly examined in literature, the estuarine

  11. Foraging ecology of sanderlings Calidris alba wintering in estuarine and non-estuarine intertidal areas

    NASA Astrophysics Data System (ADS)

    Lourenço, Pedro M.; Alves, José A.; Catry, Teresa; Granadeiro, José P.

    2015-10-01

    Outside the breeding season, most shorebirds use either estuarine or non-estuarine intertidal areas as foraging grounds. The sanderling Calidris alba is mostly associated with coastal sandy beaches, a habitat which is currently at risk worldwide due to increasing coastal erosion, but may also use estuarine sites as alternative foraging areas. We aimed to compare the trophic conditions for sanderlings wintering in estuarine and non-estuarine sites within and around the Tejo estuary, Portugal, where these two alternative wintering options are available within a relatively small spatial scale. To achieve this, we analysed sanderling diet, prey availability, foraging behaviour, and time and energy budgets in the different substrates available in estuarine and non-estuarine sites. In terms of biomass, the most important sanderling prey in the estuarine sites were siphons of the bivalve Scrobicularia plana, polychaetes, staphylinids and the gastropod Hydrobia ulvae. In non-estuarine sites the main prey were polychaetes, the bivalve Donax trunculus and chironomid larvae. Both food availability and energetic intake rates were higher on estuarine sites, and sanderlings spent a higher proportion of time foraging on non-estuarine sites. In the estuary, sanderlings foraged in muddy-sand substrate whenever it was available, achieving higher intake rates than in sandy substrates. In the non-estuarine sites they used both sandy and rocky substrates throughout the tidal cycle but had higher intakes rates in sandy substrate. Estuarine sites seem to offer better foraging conditions for wintering sanderlings than non-estuarine sites. However, sanderlings only use muddy-sand and sandy substrates, which represent a small proportion of the intertidal area of the estuary. The extent of these substrates and the current sanderling density in the estuary suggest it is unlikely that the estuary could provide alternative wintering habitat for sanderlings if they face habitat loss and

  12. Simulation modeling of estuarine ecosystems

    NASA Technical Reports Server (NTRS)

    Johnson, R. W.

    1980-01-01

    A simulation model has been developed of Galveston Bay, Texas ecosystem. Secondary productivity measured by harvestable species (such as shrimp and fish) is evaluated in terms of man-related and controllable factors, such as quantity and quality of inlet fresh-water and pollutants. This simulation model used information from an existing physical parameters model as well as pertinent biological measurements obtained by conventional sampling techniques. Predicted results from the model compared favorably with those from comparable investigations. In addition, this paper will discuss remotely sensed and conventional measurements in the framework of prospective models that may be used to study estuarine processes and ecosystem productivity.

  13. Southern RS CVn systems - Candidate list. [spectral catalog of variable binary stars

    NASA Technical Reports Server (NTRS)

    Weiler, E. J.; Stencel, R. E.

    1979-01-01

    A list of 43 candidate RS CVn binary systems in the far southern hemisphere of the sky (south of -40 deg declination) is presented. The candidate systems were selected from the first two volumes of the Michigan Spectral Catalog (1975, 1978), which provides MK classifications for southern HD stars and identifies any unusual characteristics noted for individual stellar spectra. The selection criteria used were: (1) the occurrence of Ca II H and K emission; (2) known or suspected binary nature; (3) regular light variations of zero to one magnitude; and (4) spectral type between F0 and K2 and luminosity less than bright giant (II).

  14. Aqueous geochemistry of the Thermopolis hydrothermal system, southern Bighorn Basin, Wyoming, U.S.A.

    DOE PAGESBeta

    Kaszuba, John P.; Sims, Kenneth W.W.; Pluda, Allison R.

    2014-06-01

    The Thermopolis hydrothermal system is located in the southern portion of the Bighorn Basin, in and around the town of Thermopolis, Wyoming. It is the largest hydrothermal system in Wyoming outside of Yellowstone National Park. The system includes hot springs, travertine deposits, and thermal wells; published models for the hydrothermal system propose the Owl Creek Mountains as the recharge zone, simple conductive heating at depth, and resurfacing of thermal waters up the Thermopolis Anticline.

  15. Population in trans-border regions: the Southern California-Baja California urban system.

    PubMed

    Rubin-kurtzman, J R; Ham-chande, R; Van Arsdol, M D

    1996-01-01

    "This article is a case study of population growth and composition in the Southern California-Baja California trans-border urban system (TBS). The central question guiding the research is how the combination of geographic proximity and economic integration in two very different regions affects population characteristics in the Southern California-Baja California TBS. We begin by briefly defining trans-border urban systems. We then specify the attributes of the Southern California-Baja California TBS, contrasting them with attributes observed elsewhere in the United States and Mexico.... The data are drawn primarily from the U.S. and Mexican censuses. Secondary data from a variety of sources also are discussed." PMID:12347786

  16. Anatomy of La Jolla submarine canyon system; offshore southern California

    USGS Publications Warehouse

    Paull, C.K.; Caress, D.W.; Lundsten, E.; Gwiazda, R.; Anderson, K.; McGann, M.; Conrad, J.; Edwards, B.; Sumner, E.J.

    2013-01-01

    An autonomous underwater vehicle (AUV) carrying a multibeam sonar and a chirp profiler was used to map sections of the seafloor within the La Jolla Canyon, offshore southern California, at sub-meter scales. Close-up observations and sampling were conducted during remotely operated vehicle (ROV) dives. Minisparker seismic-reflection profiles from a surface ship help to define the overall geometry of the La Jolla Canyon especially with respect to the pre-canyon host sediments. The floor of the axial channel is covered with unconsolidated sand similar to the sand on the shelf near the canyon head, lacks outcrops of the pre-canyon host strata, has an almost constant slope of 1.0° and is covered with trains of crescent shaped bedforms. The presence of modern plant material entombed within these sands confirms that the axial channel is presently active. The sand on the canyon floor liquefied during vibracore collection and flowed downslope, illustrating that the sediment filling the channel can easily fail even on this gentle slope. Data from the canyon walls help constrain the age of the canyon and extent of incision. Horizontal beds of moderately cohesive fine-grained sediments exposed on the steep canyon walls are consistently less than 1.232 million years old. The lateral continuity of seismic reflectors in minisparker profiles indicate that pre-canyon host strata extend uninterrupted from outside the canyon underneath some terraces within the canyon. Evidence of abandoned channels and point bar-like deposits are noticeably absent on the inside bend of channel meanders and in the subsurface of the terraces. While vibracores from the surface of terraces contain thin (< 10 cm) turbidites, they are inferred to be part of a veneer of recent sediment covering pre-canyon host sediments that underpin the terraces. The combined use of state of the art seafloor mapping and exploration tools provides a uniquely detailed view of the morphology within an active submarine canyon.

  17. Upper Basalt-Confined Aquifer System in the Southern Hanford Site

    SciTech Connect

    Thorne, P.

    1999-01-04

    The 1990 DOE Tiger Team Finding GW/CF-202 found that the hydrogeologic regime at the Hanford Site was inadequately characterized. This finding also identified the need for completing a study of the confined aquifer in the central and southern portions of the Hanford Site. The southern portion of the site is of particular interest because hydraulic-head patterns in the upper basalt-confined aquifer system indicate that groundwater from the Hanford central plateau area, where contaminants have been found in the aquifer, flows southeast toward the southern site boundary. This results in a potential for offsite migration of contaminants through the upper basalt-confined aquifer system. Based on the review presented in this report, available hydrogeologic characterization information for the upper basalt-confined aquifer system in this area is considered adequate to close the action item. Recently drilled offsite wells have provided additional information on the structure of the aquifer system in and near the southern part of the Hanford Site. Information on hydraulic properties, hydrochemistry, hydraulic heads and flow directions for the upper basalt-confined aquifer system has been re-examined and compiled in recent reports including Spane and Raymond (1993), Spane and Vermeul ( 1994), and Spane and Webber (1995).

  18. Downwelling wind, tides, and estuarine plume dynamics

    NASA Astrophysics Data System (ADS)

    Lai, Zhigang; Ma, Ronghua; Huang, Mingfen; Chen, Changsheng; Chen, Yong; Xie, Congbin; Beardsley, Robert C.

    2016-06-01

    The estuarine plume dynamics under a downwelling-favorable wind condition were examined in the windy dry season of the Pearl River Estuary (PRE) using the PRE primitive-equation Finite-Volume Community Ocean Model (FVCOM). The wind and tide-driven estuarine circulation had a significant influence on the plume dynamics on both local and remote scales. Specifically, the local effect of downwelling-favorable winds on the plume was similar to the theoretical descriptions of coastal plumes, narrowing the plume width, and setting up a vertically uniform downstream current at the plume edge. Tides tended to reduce these plume responses through local turbulent mixing and advection from upstream regions, resulting in an adjustment of the isohalines in the plume and a weakening of the vertically uniform downstream current. The remote effect of downwelling-favorable winds on the plume was due to the wind-induced estuarine sea surface height (SSH), which strengthened the estuarine circulation and enhanced the plume transport accordingly. Associated with these processes, tide-induced mixing tended to weaken the SSH gradient and thus the estuarine circulation over a remote influence scale. Overall, the typical features of downwelling-favorable wind-driven estuarine plumes revealed in this study enhanced our understanding of the estuarine plume dynamics under downwelling-favorable wind conditions.

  19. Strength and time lag of relationships between human pressures and fish-based metrics used to assess ecological quality of estuarine systems

    NASA Astrophysics Data System (ADS)

    Pasquaud, Stéphanie; Courrat, Anne; Fonseca, Vanessa F.; Gamito, Rita; Gonçalves, Catarina I.; Lobry, Jérémy; Lepage, Mario; Costa, Maria José; Cabral, Henrique

    2013-12-01

    Fish-based multi-metric indices have been widely developed in ecological quality assessments of estuaries in the past few years, but the ability of these indices and their respective metrics to respond to human pressures may be quite different. Based on a group consensus approach eliciting information from multiple experts integrating published literature, this work evaluated the strength and time-lag of the response of eight fish-based indices (AFI, EFAI, ELFI, Z-EBI, TFCI, EBI, EFCI, IBI), and their respective metrics, in relation to several human pressures (chemical pollution, eutrophication, loss of habitat, water turbidity, habitat fragmentation, fishing mortalities, invasive species, water temperature changes and flow changes). Results pointed out that most of the metrics detect several human pressures, being difficult to identify a particular pressure effect and its source. The majority of the metrics analysed presented a weak relationship with pressures and/or respond in a long time period. The metrics responding to chemical pollution and loss of habitat were generally the ones with stronger relationships, but their responses were often in a long time period. Consequently, the fish-based indices analysed did not detect all the pressures with the same sensitivity in terms of strength and time lag. This clearly collides with the needs for water ecological quality assessments, management and rehabilitation of estuarine ecosystems, and highlighted the value of metrics, especially the ones that are specific of certain pressures.

  20. Sweet Corn, Southern Pea, and Watermelon Yields following Winter Annual Grazing across Tillage Systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vegetable grower income may be supplemented by winter annual grazing of stockers, but excess soil compaction can decrease vegetable yields. We initiated a study to determine the optimal tillage system for sweet corn (Zea mays, L.) cv. ‘Silver Queen’, southern pea (Vigna unguiculata L.) cv. ‘Pinkeye...

  1. Strategic adaptation of nitrogen management for el nino southern oscillation-induced winter wheat system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The rainfall anomaly (RA) associated with El Niño-Southern Oscillation (ENSO) has various unwanted impacts on agricultural system globally. The loss of inorganic nitrogen (N) depending on extreme wet or dry conditions is a major concern. The main objective of this study was to adapt site-specific N ...

  2. 76 FR 43803 - Prevailing Rate Systems; Redefinition of the Northeastern Arizona and Southern Colorado...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-22

    ... INFORMATION: On February 22, 2011, the U.S. Office of Personnel Management (OPM) issued a proposed rule (76 FR... geographic boundaries of the Northeastern Arizona and Southern Colorado appropriated fund Federal Wage System... survey area. DATES: This regulation is effective on August 22, 2011. FOR FURTHER INFORMATION...

  3. Variations in Reading Achievement across 14 Southern African School Systems: Which Factors Matter?

    ERIC Educational Resources Information Center

    Hungi, Njora; Thuku, Florence W.

    2010-01-01

    In this study the authors employed a multilevel analysis procedure in order to examine the pupil and school levels factors that contributed to variation in reading achievement among Grade 6 primary school pupils in 14 southern African school systems (Botswana, Kenya, Lesotho, Malawi, Mauritius, Mozambique, Namibia, Seychelles, South Africa,…

  4. Pathobiology of marine and estuarine organisms

    SciTech Connect

    Couch, J.A.; Fournie, J.W.

    1992-12-01

    The book is an up-to-date compendium of scientific findings related to diseases of marine and estuarine organisms. The information was presented at the Gulf Breeze Symposium on Marine and Estuarine Disease Research sponsored by the U.S. Environmental Protection Agency (EPA) Environmental Monitoring and Assessment Program (EMAP) held in October 1990 on Pensacola Beach, Florida. Authors review the state-of-the-science and recommend research for future studies of the impact of xenobiotics and other anthropogenic stress factors on disease processes in marine and estuarine organisms.

  5. Interseismic strain accumulation and the earthquake potential on the southern San Andreas fault system.

    PubMed

    Fialko, Yuri

    2006-06-22

    The San Andreas fault in California is a mature continental transform fault that accommodates a significant fraction of motion between the North American and Pacific plates. The two most recent great earthquakes on this fault ruptured its northern and central sections in 1906 and 1857, respectively. The southern section of the fault, however, has not produced a great earthquake in historic times (for at least 250 years). Assuming the average slip rate of a few centimetres per year, typical of the rest of the San Andreas fault, the minimum amount of slip deficit accrued on the southern section is of the order of 7-10 metres, comparable to the maximum co-seismic offset ever documented on the fault. Here I present high-resolution measurements of interseismic deformation across the southern San Andreas fault system using a well-populated catalogue of space-borne synthetic aperture radar data. The data reveal a nearly equal partitioning of deformation between the southern San Andreas and San Jacinto faults, with a pronounced asymmetry in strain accumulation with respect to the geologically mapped fault traces. The observed strain rates confirm that the southern section of the San Andreas fault may be approaching the end of the interseismic phase of the earthquake cycle. PMID:16791192

  6. Development of a Hydrodynamic Model for Skagit River Estuary for Estuarine Restoration Feasibility Assessment

    SciTech Connect

    Yang, Zhaoqing; Liu, Hedong; Khangaonkar, Tarang P.

    2006-08-03

    The Skagit River is the largest river in the Puget Sound estuarine system. It discharges about 39% of total sediment and more than 20% of freshwater into Puget Sound. The Skagit River delta provides rich estuarine and freshwater habitats for salmon and many other wildlife species. Over the past 150 years, economic development in the Skagit River delta has resulted in significant losses of wildlife habitat, particularly due to construction of dikes. Diked portion of the delta is known as Fir Island where irrigation practices for agriculture land over the last century has resulted in land subsidence. This has also caused reduced efficiency of drainage network and impeded fish passages through the area. In this study, a three-dimensional tidal circulation model was developed for the Skagit River delta to assist estuarine restoration in the Fir Island area. The hydrodynamic model used in the study is the Finite Volume Coastal Ocean Model (FVCOM). The hydrodynamic model was calibrated using field data collected from the study area specifically for the model development. Wetting and drying processes in the estuarine delta are simulated in the hydrodynamic model. The calibrated model was applied to simulate different restoration alternatives and provide guidance for estuarine restoration and management. Specifically, the model was used to help select and design configurations that would improve the supply of sediment and freshwater to the mudflats and tidal marsh areas outside of diked regions and then improve the estuarine habitats for salmon migration.

  7. The impact of electric vehicles on the Southern California Edison System

    SciTech Connect

    Ford, A.

    1992-07-01

    This report describes the results of the first phase of an investigation of the impacts of electric vehicles (EVs) in southern California. The investigation focuses on the Southern California Edison Company (SCE) which provides electric service for approximately 60% of southern California. The project is supported by the Air Quality Impacts of Energy Efficiency'' Program of the California Institute for Energy Efficiency (CIEE). The first phase of the research is organized around how EVs might be viewed by customers, vehicle manufacturers and electric utility companies. The vehicle manufacturers' view has been studied with special emphasis on the role of marketable permit systems. The utilities' view of EVs is the subject of this report. The review is particularly important as several case studies of EVs in southern California have been conducted in recent years. The dynamics of a growing population of EVs is explained. Chapter 5 explains a simple method of deriving the electricity demands which could result from the operation of EVs in southern California. The method is demonstrated for several simple examples and then used to find the demands associated with each of the eight EV scenarios. Chapter 6 reports the impacts on SCE operations from the new demands for electricity. Impacts are summarized in terms of system operating costs, reliability of service, and changes in the utility's average electric rate. Chapter 7 turns to the emissions of air pollutants released by the operation of EVs, conventional vehicles (CVs) and power plants. Chapter 8 takes the air pollution analysis one step further by examining the possible reduction in ambient ozone concentration in southern California.

  8. The impact of electric vehicles on the Southern California Edison System. Final report

    SciTech Connect

    Ford, A.

    1992-07-01

    This report describes the results of the first phase of an investigation of the impacts of electric vehicles (EVs) in southern California. The investigation focuses on the Southern California Edison Company (SCE) which provides electric service for approximately 60% of southern California. The project is supported by the ``Air Quality Impacts of Energy Efficiency`` Program of the California Institute for Energy Efficiency (CIEE). The first phase of the research is organized around how EVs might be viewed by customers, vehicle manufacturers and electric utility companies. The vehicle manufacturers` view has been studied with special emphasis on the role of marketable permit systems. The utilities` view of EVs is the subject of this report. The review is particularly important as several case studies of EVs in southern California have been conducted in recent years. The dynamics of a growing population of EVs is explained. Chapter 5 explains a simple method of deriving the electricity demands which could result from the operation of EVs in southern California. The method is demonstrated for several simple examples and then used to find the demands associated with each of the eight EV scenarios. Chapter 6 reports the impacts on SCE operations from the new demands for electricity. Impacts are summarized in terms of system operating costs, reliability of service, and changes in the utility`s average electric rate. Chapter 7 turns to the emissions of air pollutants released by the operation of EVs, conventional vehicles (CVs) and power plants. Chapter 8 takes the air pollution analysis one step further by examining the possible reduction in ambient ozone concentration in southern California.

  9. Ecohydraulics and Estuarine Wetland Rehabilitation

    NASA Astrophysics Data System (ADS)

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

    2004-12-01

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

  10. Methylmercury production in estuarine sediments: role of organic matter

    PubMed Central

    Schartup, Amina T.; Mason, Robert P.; Balcom, Prentiss H.; Hollweg, Terill A.; Chen, Celia Y.

    2013-01-01

    Methylmercury (MeHg) affects wildlife and human health mainly through marine fish consumption. In marine systems, MeHg is formed from inorganic mercury (HgII) species primarily in sediments then accumulates and biomagnifies in the food web. Most of the fish consumed in the US are from estuarine and marine systems highlighting the importance of understanding MeHg formation in these productive regions. Sediment organic matter has been shown to limit mercury methylation in estuarine ecosystems, as a result it is often described as the primary control over MeHg production. In this paper, we explore the role of organic matter by looking at the effects of its changing sediment concentrations on the methylation rates across multiple estuaries. We measured sedimentary MeHg production at eleven estuarine sites that were selected for their contrasting biogeochemical characteristics, mercury (Hg) content, and location in the Northeastern US (ME, NH, CT, NY, and NJ). Sedimentary total Hg concentrations ranged across five orders of magnitude, increasing in concentration from the pristine, sandy sediments of Wells (ME), to industrially contaminated areas like Portsmouth (NH) and Hackensack (NJ). We find that methylation rates are the highest at locations with high Hg content (relative to carbon), and that organic matter does not hinder mercury methylation in estuaries. PMID:23194318

  11. Enhancing malaria control using a computerised management system in southern Africa

    PubMed Central

    Booman, Marlize; Sharp, Brian L; Martin, Carrin L; Manjate, Bonifacio; la Grange, Jacobus J; Durrheim, David N

    2003-01-01

    Background Malaria control programmes utilising indoor residual spraying are only effective if a high coverage of targeted structures is achieved and an insecticide that is effective against the specific mosquito vector is correctly applied. Ongoing monitoring of spraying operations is essential to assure optimal programme performance and early corrective action, where indicated. Methods Successful development and application of a computerised spraying operations management system in Mpumalanga Province, South Africa during 1998 resulted in its adaptation and introduction in neighbouring Maputo Province, southern Mozambique during 2000. The structure and components of this computerised management system are described, and its' operational benefit in southern Mozambique, where community-based spray operators apply intradomiciliary insecticide, are reviewed. Conclusions The computerised management system allowed malaria programme management and field supervisors to monitor spraying coverage, insecticide consumption and application rates on an ongoing basis. The system supported a successful transition to community-based spraying, while assuring correct insecticide application and spraying completion according to schedule. PMID:12816547

  12. The European Southern Observatory-MIDAS table file system

    NASA Technical Reports Server (NTRS)

    Peron, M.; Grosbol, P.

    1992-01-01

    The new and substantially upgraded version of the Table File System in MIDAS is presented as a scientific database system. MIDAS applications for performing database operations on tables are discussed, for instance, the exchange of the data to and from the TFS, the selection of objects, the uncertainty joins across tables, and the graphical representation of data. This upgraded version of the TFS is a full implementation of the binary table extension of the FITS format; in addition, it also supports arrays of strings. Different storage strategies for optimal access of very large data sets are implemented and are addressed in detail. As a simple relational database, the TFS may be used for the management of personal data files. This opens the way to intelligent pipeline processing of large amounts of data. One of the key features of the Table File System is to provide also an extensive set of tools for the analysis of the final results of a reduction process. Column operations using standard and special mathematical functions as well as statistical distributions can be carried out; commands for linear regression and model fitting using nonlinear least square methods and user-defined functions are available. Finally, statistical tests of hypothesis and multivariate methods can also operate on tables.

  13. Rapid climatic signal propagation from source to sink in a southern California sediment-routing system

    USGS Publications Warehouse

    Covault, J.A.; Romans, B.W.; Fildani, A.; McGann, M.; Graham, S.A.

    2010-01-01

    Terrestrial source areas are linked to deep-sea basins by sediment-routing systems, which only recently have been studied with a holistic approach focused on terrestrial and submarine components and their interactions. Here we compare an extensive piston-core and radiocarbon-age data set from offshore southern California to contemporaneous Holocene climate proxies in order to test the hypothesis that climatic signals are rapidly propagated from source to sink in a spatially restricted sediment-routing system that includes the Santa Ana River drainage basin and the Newport deep-sea depositional system. Sediment cores demonstrate that variability in rates of Holocene deep-sea turbidite deposition is related to complex ocean-atmosphere interactions, including enhanced magnitude and frequency of the North American monsoon and El Ni??o-Southern Oscillation cycles, which increased precipitation and fluvial discharge in southern California. This relationship is evident because, unlike many sediment-routing systems, the Newport submarine canyon-and-channel system was consistently linked tothe Santa Ana River,which maintained sediment delivery even during Holocene marine transgression and highstand. Results of this study demonstrate the efficiency of sediment transport and delivery through a spatially restricted, consistently linked routing system and the potential utility of deep-sea turbidite depositional trends as paleoclimate proxies in such settings. ?? 2010 by The University of Chicago.

  14. Managing bay and estuarine ecosystems for multiple services

    USGS Publications Warehouse

    Needles, Lisa A.; Lester, Sarah E.; Ambrose, Richard; Andren, Anders; Beyeler, Marc; Connor, Michael S.; Eckman, James E.; Costa-Pierce, Barry A.; Gaines, Steven D.; Lafferty, Kevin D.; Lenihan, Junter S.; Parrish, Julia; Peterson, Mark S.; Scaroni, Amy E.; Weis, Judith S.; Wendt, Dean E.

    2013-01-01

    Managers are moving from a model of managing individual sectors, human activities, or ecosystem services to an ecosystem-based management (EBM) approach which attempts to balance the range of services provided by ecosystems. Applying EBM is often difficult due to inherent tradeoffs in managing for different services. This challenge particularly holds for estuarine systems, which have been heavily altered in most regions and are often subject to intense management interventions. Estuarine managers can often choose among a range of management tactics to enhance a particular service; although some management actions will result in strong tradeoffs, others may enhance multiple services simultaneously. Management of estuarine ecosystems could be improved by distinguishing between optimal management actions for enhancing multiple services and those that have severe tradeoffs. This requires a framework that evaluates tradeoff scenarios and identifies management actions likely to benefit multiple services. We created a management action-services matrix as a first step towards assessing tradeoffs and providing managers with a decision support tool. We found that management actions that restored or enhanced natural vegetation (e.g., salt marsh and mangroves) and some shellfish (particularly oysters and oyster reef habitat) benefited multiple services. In contrast, management actions such as desalination, salt pond creation, sand mining, and large container shipping had large net negative effects on several of the other services considered in the matrix. Our framework provides resource managers a simple way to inform EBM decisions and can also be used as a first step in more sophisticated approaches that model service delivery.

  15. Floristic evolution in an agroforestry system cultivation in Southern Brazil.

    PubMed

    Silva, Luís C R; Machado, Sebastião A; Galvão, Franklin; Figueiredo, Afonso

    2016-06-01

    Bracatinga (Mimosa scabrella Bentham) is an important pioneer tree species in Ombrophylous Mixed Forest of Brazil and is widely used as an energy source. In traditional agroforestry systems, regeneration is induced by fire, then pure and dense stands known as bracatinga stands (bracatingais) are formed. In the first year, annual crops are intercalated with the seedlings. At that time the seedlings are thinned, then the stands remain at a fallow period and cut at seven years old. The species is very important mainly for small landowners. We studied the understory species that occur naturally during the succession over several years in order to manage them rationally in the future and maintain the natural vegetation over time. Three to 20 year-old Bracatinga stands were sampled between 1998 and 2011. All tree species with diameter at breast height (DBH) ≥ 5 cm were measured.The floristic evolution was assessed with respect to Sociability Index, the Shannon Diversity Index and the Pielou Evenness Index. Graphs of rank/abundance over different age groups were evaluated using the Kolmogorov-Smirnov test. We identified 153 species dispersed throughout the understory and tend to become aggregated over time. PMID:27276374

  16. Mercury in estuarine sediments of the Manguaba and Botafogo River : A background and baseline values proposition in comparison to relatively well preserved and polluted aquatic systems under tropical countries

    NASA Astrophysics Data System (ADS)

    Lima, Marta

    2013-04-01

    Mercury in estuarine sediments of the Manguaba and Botafogo River : A background and baseline values proposition in comparison to relatively well preserved and polluted aquatic systems under tropical countries Lima, Marta1; Menor, Eldemar2; Lima, Enjolras3; Neumann, Virginio4 1MFGTransportes, Brazil; 2Federal University of Pernambuco, Brazil 3Servico Geologico do Brasil-CPRM, Brazil 4Federal University of Pernambuco, Brazil Heavy metal (HM) concentrations in estuarine sediments of the Botafogo and Manguaba river, North-eastern Brazil were investigated on basis of samples from a bottom core drill performed 4km from the mouth of the rivers. Total sediments (TS) of the sliced profiles (62 cm, Botafogo river and 87 cm, Manguaba river ) were submitted to chemical analysis (51 elements), mineralogical analysis (XRD) and statistical study, followed by stoichiometric calculations. Geochronologic determinations of 210Pb allowed studying the evolution of the contamination level approximately 150 year-old interval in the Botafogo river. Mercury (Hg) and Arsenic (As) are emphasized because of a chlorine-soda industry that dumps its effluents about 15 km upstream of the estuary and extensive cultivation of sugarcane existent in this watershed. Hg background in pelitic total sediments (PTS) was certain established considering the Hg content (126 ppb) in sedimentary intervals previous to 1910. The production of chlorine-soda (since 1963) coincides with a drastic increase of the Hg concentrations and contemporary values around 6.000 ppb, without interruption in the pollutant process. The conclusions found that the Hg was the main indicator of anthropogenic contribution in the sediments of the Botafogo river. On the other hand, an increase in the Hg-As concentrations has been observed at the last decades due to an increase of the clay mineral fraction in TS of the Manguaga river. This scenario indicates that the accumulation of HM has been constant since the last decades, under a

  17. Estuarine nitrifiers: New players, patterns and processes

    NASA Astrophysics Data System (ADS)

    Bernhard, Anne E.; Bollmann, Annette

    2010-06-01

    Ever since the first descriptions of ammonia-oxidizing Bacteria by Winogradsky in the late 1800s, the metabolic capability of aerobic ammonia oxidation has been restricted to a phylogenetically narrow group of bacteria. However, the recent discovery of ammonia-oxidizing Archaea has forced microbiologists and ecologists to re-evaluate long-held paradigms and the role of niche partitioning between bacterial and archaeal ammonia oxidizers. Much of the current research has been conducted in open ocean or terrestrial systems, where community patterns of archaeal and bacterial ammonia oxidizers are highly congruent. Studies of archaeal and bacterial ammonia oxidizers in estuarine systems, however, present a very different picture, with highly variable patterns of archaeal and bacterial ammonia oxidizer abundances. Although salinity is often identified as an important factor regulating abundance, distribution, and diversity of both archaeal and bacterial ammonia oxidizers, the data suggest that the variability in the observed patterns is likely not due to a simple salinity effect. Here we review current knowledge of ammonia oxidizers in estuaries and propose that because of their steep physico-chemical gradients, estuaries may serve as important natural laboratories in which to investigate the relationships between archaeal and bacterial ammonia oxidizers.

  18. EFFECTS OF PENTACHLOROPHENOL ON DEVELOPMENT OF ESTUARINE COMMUNITIES

    EPA Science Inventory

    Pentachlorophenol affected the composition of communities of estuarine organisms developed in sand from planktonic larvae in estuarine water that flowed through ten control aquaria and ten aquaria per exposure concentration averaging 7, 76, or 622 micrograms/liter. Annelids, arth...

  19. Measuring the acute toxicity of estuarine sediments

    SciTech Connect

    DeWitt, T.H.; Swartz, R.C.; Lanberson, J.O.

    1989-01-01

    Estuarine sediments frequently are repositories and sources of anthropogenic contaminants. Toxicity is one method of assessing the environmental quality of sediments, yet because of the extreme range of salinities that characterize estuaries few infaunal organisms have both the physiological tolerance and sensitivity to chemical contaminants to serve in estuarine sediment toxicity tests. The study describes research on the estuarine burrowing amphipod, Eohaustorius estuarius Bosworth, 1973, whose survival was >95% in control sediments across a 2 to 28% salinity range over 10-d periods. E. estuarius also was acutely sensitive to low sediment concentrations of the polycyclic aromatic hydrocarbon, fluoranthene (LC50 approximately = 10.6 mg/kg), and its sensitivity to fluoranthene was not affected by salinity. E. estuarius was almost as sensitive as Rhepoxynius abronius to fluoranthene and to field-collected sediments from Puget Sound urban and industrial bays. E. estuarius was also more tolerant of very fine, uncontaminated sediments than R. abronius. Furthermore, E. estuarius was more sensitive to sediments spiked with fluoranthene than the freshwater amphipod, Hyalella azteca. E. estuarius, and possibly other estuarine haustoriid species, appears to be an excellent candidate for testing the acute toxicity if estuarine and marine sediments.

  20. Global positioning system reoccupation of early triangulation sites - Tectonic deformation of the Southern Coast Ranges

    NASA Technical Reports Server (NTRS)

    Shen, Zheng-Kang; Jackson, David D.

    1993-01-01

    We study tectonic deformation in the Southern Coast Range, California. We use triangulation and astronomic azimuth data collected since 1875, trilateration since 1970, and global positioning system data collected from 1986 to 1987. Two modeling techniques have been used. An elastic block-fault model is applied to study the tectonic motion of the San Andreas Fault and the San Gregorio-Hosgri Fault. Station velocities are modeled to study regional deformations. Results show that the regional deformation is predominantly controlled by deep strike-slip motion along the San Andreas Fault, at a rate of 33 +/- 2 mm/yr. Deep slip along the San Gregorio-Hosgri Fault is about 0-4 mm/yr, assuming a locked suit to a depth of 20 km. Convergence normal to the San Andreas Fault in the Southern Coast Ranges is not greater than 0.02 microrad/yr.

  1. Hydrogeology, ground-water movement, and subsurface storage in the Floridan aquifer system in southern Florida

    USGS Publications Warehouse

    Meyer, Frederick W.

    1989-01-01

    The Floridan aquifer system of southern Florida is composed chiefly of carbonate rocks that range in age from early Miocene to Paleocene. The top of the aquifer system in southern Florida generally is at depths ranging from 500 to 1,000 feet, and the average thickness is about 3,000 feet. It is divided into three general hydrogeologic units: (1) the Upper Floridan aquifer, (2) the middle confining unit, and (3) the Lower Floridan aquifer. The Upper Floridan aquifer contains brackish ground water, and the Lower Floridan aquifer contains salty ground water that compares chemically to modern seawater. Zones of high permeability are present in the Upper and Lower Floridan aquifers. A thick, cavernous dolostone in the Lower Floridan aquifer, called the Boulder Zone, is one of the most permeable carbonate units in the world (transmissivity of about 2.5 x 107 feet squared per day). Ground-water movement in the Upper Floridan aquifer is generally southward from the area of highest head in central Florida, eastward to the Straits of Florida, and westward to the Gulf of Mexico. Distributions of natural isotopes of carbon and uranium generally confirm hydraulic gradients in the Lower Floridan aquifer. Groundwater movement in the Lower Floridan aquifer is inland from the Straits of Florida. The concentration gradients of the carbon and uranium isotopes indicate that the source of cold saltwater in the Lower Floridan aquifer is seawater that has entered through the karat features on the submarine Miami Terrace near Fort Lauderdale. The relative ages of the saltwater suggest that the rate of inland movement is related in part to rising sea level during the Holocene transgression. Isotope, temperature, and salinity anomalies in waters from the Upper Floridan aquifer of southern Florida suggest upwelling of saltwater from the Lower Floridan aquifer. The results of the study support the hypothesis of circulating relatively modern seawater and cast doubt on the theory that the

  2. Estuarine circulation in the Taranto Seas.

    PubMed

    Pascalis, Francesca De; Petrizzo, Antonio; Ghezzo, Michol; Lorenzetti, Giuliano; Manfè, Giorgia; Alabiso, Giorgio; Zaggia, Luca

    2016-07-01

    The Taranto basin is a shallow water marine system in the South of Italy characterized by the presence of a lagoon environment together with a semi-enclosed bay connected to the Ionian Sea. This marine system experienced over the last few decades strong biochemical pollution and environmental degradation, and it is considered a hotspot study site for economic, ecological and scientific reasons. The aim of this study was to examine, on an annual temporal scale and with high spatial resolution, the main hydrodynamical processes and transport scales of the system by means of a 3D finite element numerical model application, adopting the most realistic forcing available. The model allowed us to assess the role played by baroclinic terms in the basin circulation, describing its estuarine nature. In particular, the main features of water circulation, salinity and temperature distribution, water renewal time and bottom stress were investigated. Our results allowed us to equate this system dynamic to that of a weakly stratified estuary, identifying the main driving sources of this mechanism. The vertical stratification over the whole year was proved to be stable, leading to a dual circulation flowing out on the surface, mainly through Porta Napoli channel, and inflowing on the bottom mainly through Navigabile channel. This process was responsible also for the renewal time faster on the bottom of the Mar Piccolo basin than the surface. Due to the great importance of the Taranto basin for what concerns sediment pollution, also the effect of currents in terms of bottom stress was investigated, leading to the conclusion that only in the inlets area the values of bottom stress can be high enough to cause erosion. PMID:26408109

  3. Habitat residency and movement patterns of Centropomus parallelus juveniles in a subtropical estuarine complex.

    PubMed

    Daros, F A; Spach, H L; Correia, A T

    2016-05-01

    Sixty Centropomus parallelus juveniles were collected in March 2013 in two locations (Tromomó and Guaraguaçu) inside the Paranaguá estuarine complex, southern Brazil. The habitat residency and movement patterns of the individuals were inferred from Sr:Ca ratios and age recorded in the otoliths. Data suggest that the species spawns preferentially in brackish areas mainly from October to January, and that growth rate during the early juvenile stage could be influenced by environmental salinity. Furthermore, the data also show that C. parallelus can occupy diverse salinity habitats and migrate among marine, brackish and freshwater areas within the Paranaguá estuarine complex, showing a high environmental plasticity and adaptation. PMID:27020945

  4. The Role Of Coastal Management In Regulating Estuarine Fluxes

    NASA Astrophysics Data System (ADS)

    Jickells, T. D.

    2014-12-01

    Human activity is known to be increasing the fluxes of many nutrients and trace elements in many river systems. However, the impact of riverine inputs depends not only on the riverine nutrient flux, but also on its retention in estuaries and near shore coastal systems. The retention of nutrients and trace elements in coastal systems depends at least in part on particle water interactions. These interactions in turn depend on the physical configuration of the system which regulates processes such as resuspension and water-sediment interactions. Human activity is massively altering the shape of many estuaries by activities such as reclamation and flood defence. These changes have obvious and well documented ecological impacts. I will show using examples from UK systems how these changes in estuarine "geography" also greatly alter the effectiveness of estuaries as filters for nutrients and trace elements, with the potential to have a major impact on the fluxes of fluvial material to the continental shelf on regional scales. Rising sea levels are beginning to enforce a change of management strategy in coastal systems and this in turn may have major impacts on estuarine nutrient retention.

  5. Toxicity of ozonated estuarine water to juvenile blue crabs (Callinectes sapidus) and Juvenile Atlantic menhaden (Brevoortia tyrannus)

    SciTech Connect

    Richardson, L.B.; Burton, D.T.

    1981-02-01

    Large quantitites of estuarine and marine water are treated with chlorine to prevent condenser system fouling at power plants. Chlorine and its residual by-products, however, are toxic to many forms of aquatic life. Ozone is one alternative oxidant which has proven to be an effective biocide and disinfectant in many fresh water applications. Ozonation of estuarine and marine waters, however, may produce residual compounds similar to those produced by chlorination. This study was initiated to provide baseline information on the toxicity of ozonated estuarine water to two representative estuarine species. The blue crab, Callinectes sapidus Rathbun, and the Atlantic menhaden, Brevoortia tyrannus Latrobe, were selected because of their wide distribution and commercial importance. The toxicity of ozone has been compared with chlorine toxicity data from the literature in an effort to examine possible similarities in toxicity.

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

    PubMed

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

    2015-10-15

    Little knowledge is available about the potential impact of commercial silver nanoparticles (Ag-NPs) on estuarine microbial communities. The Hugli river estuary, India, is susceptible to heavy metals pollution through boat traffic, and there is the potential for Ag-NP exposure via effluent discharged from ongoing municipal and industrial activities located in close proximity. This study investigated the effects of commercial Ag-NPs on native microbial communities in estuarine sediments collected from five stations, using terminal restriction fragment length polymorphism (T-RFLP) technique. An increase in the number of bacteria in consortium in sediments was observed following exposure to Ag-NPs. In general microbial communities may be resistant in estuarine systems to the antimicrobial effects of commercial Ag-NPs, but key microorganisms, such as Pelobacter propionicus, disappeared following exposure to Ag-NPs. In conclusion, the T-RFLP analysis indicated that Ag-NPs have the potential to shape estuarine sediment bacterial community structure. PMID:26231062

  7. Estuarine density fronts and their effect on oil slicks

    NASA Technical Reports Server (NTRS)

    Klemas, V. (Principal Investigator); Polis, D. F.; Davis, G. R.

    1976-01-01

    The author has identified the following significant results. Estuarine fronts represent regions of extremely high gradient or discontinuity in various parameters of physical interest, the most important being the water velocity and density fields. Aircraft and boats were combined to study the behavior of different types of fronts in Delaware Bay and their effect on pollutants in order to provide a basis for improving an oil drift and spreading model. Imagery from the LANDSAT satellites provided the most effective means of determining the location and extent of frontal systems over all portions of the tidal cycle. This data is being used to modify the oil drift and spreading model.

  8. The diamondback terrapin: The biology, ecology, cultural history, and conservation status of an obligate estuarine turtle

    USGS Publications Warehouse

    Hart, K.M.; Lee, D.S.

    2006-01-01

    Ranging from Cape Cod to nearly the Texas-Mexico border, the diamondback terrapin (Malaclemys terrapin) is the only species of North American turtle restricted to estuarine systems. Despite this extensive distribution, its zone of occurrence is very linear, and in places fragmented, resulting in a relatively small total area of occupancy. On a global scale, excluding marine species, few turtles even venture into brackish water on a regular basis, and only two Asian species approach the North American terrapin's dependency on estuarine habitats. Here we describe some of the biological and behavioral adaptations of terrapins that allow them to live in the rather harsh estuarine environment. In this chapter we review the natural and cultural history of this turtle, discuss conservation issues, and provide information on the types of research needed to make sound management decisions for terrapin populations in peril.

  9. Inconsistencies in coastal dune genesis and development in the western Mediterranean Cabopino Dune system, southern Spain

    NASA Astrophysics Data System (ADS)

    Guisado-Pintado, Emilia; Malvárez, Gonzalo; Jackson, Derek; Navas, Fatima

    2016-04-01

    It is generally agreed that a falling sea level regime is required in the long term to establish dunes as distinctive landform features along a coast. Sedimentary (supply) bodies from fluvial, glacial sources or marine platform processes also need to be in place. In most Atlantic-facing coastal dune systems the current morpho-sedimentary structures are usually associated with the period between 18K BP and present when both glacial and riverine sediments emplaced sediments within the active zone of present sea level to help form beaches and dunes. Mediterranean coastal dunes fronted by steep continental shelves, such as in the western Mediterranean coast of southern Spain are, however, not associated with glacial deposits and thus are only present in association with river mouths and/or coastal lagoons. Their development is attributed to very recent sediment supply, which, combined with other forcing factors such as wind and waves, several orders of magnitude below those of north Atlantic systems, explains their limited extent. Some coastal dune fields however, do not seem to respond to this general pattern because of their scale and, more importantly, their origin linked possibly to marine platform processes rather than riverine or lagoonal development. Here, we examine the Cabopino dune system in southern Spain offering a conceptual model of their genesis and development as an "Atlantic" dune system within a Mediterranean setting. This is demonstrated by their scale (the largest in the Spanish Mediterranean) and their morphodynamic link to nearshore and platform processes in the last 18,000 years.

  10. Fluvial systems response to rift margin tectonics: Makhtesh Ramon area, southern Israel

    NASA Astrophysics Data System (ADS)

    Ben-David, Ram; Eyal, Yehuda; Zilberman, Ezra; Bowman, Dan

    2002-06-01

    The geomorphic evolution of Makhtesh Ramon, a feather-shaped erosional valley, and the Nahal Neqarot drainage system to the south occurred largely in response to tectonic activity along the Dead Sea Rift and its western shoulder. Remnants of Miocene clastic sediments (Hazeva Formation) deposited on an erosional peneplain that formed over this area during the Oligocene epoch provide a datum plane for reconstructing subsequent fluvial evolution. These clastic remnants are presently located on the shoulders of Makhtesh Ramon at various elevations. The peneplain truncating the Makhtesh Ramon block has been tilted 0.7% northeastward since the Pliocene epoch (post-Hazeva Formation), whereas that of the Neqarot syncline, south of the Ramon, has been tilted 1.2%. The elliptical exposure of friable Lower Cretaceous sandstone, exposed in the core of the truncated Ramon structure, governed the development of a new ENE directed (riftward) drainage system through capture of streams that previously drained toward the Mediterranean Sea to the northwest. Incised fluvial gaps in the southern rim of Makhtesh Ramon and alluvial fan relicts within Makhtesh Ramon attest to original drainage into the Makhtesh from the south. Remnants of the Plio-Pleistocene Arava Conglomerate on the eastern end of the Neqarot syncline contain clasts from rocks exposed within Makhtesh Ramon, also indicating that streams flowed into the Makhtesh from the southern Neqarot block through the western gaps, then turning eastward and exiting the Makhtesh via the next (Sha'ar-Ramon) gap to the east. Further down-faulting of the Neqarot block during Mid-Late Pleistocene time led to westward retreat of the Neqarot valley and capture of the last stream flowing northward into the Ramon, leaving the modern Makhtesh Ramon isolated from the southern drainage system.

  11. Turing Patterns in Estuarine Sediments by Microbiological Activity

    NASA Astrophysics Data System (ADS)

    De Morais Mendonca Teles, Antonio

    2016-07-01

    The use of Turing mechanisms and lattice Lotka-Volterra model (LLV), also by means of the non-extensive statistical mechanics, can mathematically describe well the phenomena of clustering and their associated boundaries with fractal dimensionality, which occurs in various natural situations, among them, biogeochemical processes via microorganisms in estuarine and marine sediments on the planet Earth. The author did an experimental analysis in field work which took into account the spatial and temporal behavior of Turing patterns, in the form of microbial activity within estuarine subsurface sediments. We show we can find the characteristics of clustering and fractallity which are present in the dynamical LLV model and Turing patterns mechanisms, and the non-extensive statistical mechanics could be used to find the q-entropy (Sq), and other non-equilibrium statistical parameters of the studied estuarine (Caraís lagoon) subsurface biogeochemical system. In this paper, the author suggests that such kinds of subsurface ecological systems are of interest to Astrobiology because if we find Turing-type clustered geomorphological patterns, below meter scale, on the near subsurface and inside rocks at the surface of planet Mars, and also find non-equilibrium statistical parameters (temperature, [F], [C], [S], etc.), displaying Turing-type mechanism, in the aquatic environments of the internal seas of planets Jupiter's moon Europa and the internal global ocean of Saturn's moon Enceladus, that could mean that possible hypothetical biogeochemical activities are present in such places. This could be a bio-indicator tool. And with further studies we could find the q-entropy Sq to establish better defined statistical mechanical parameters for such environments and to refine models for their evolution, as we do on planet Earth.

  12. Holocene history of the estuarine area surrounding Portage, Alaska, as recorded in a 93 m core.

    USGS Publications Warehouse

    Bartsch-Winkler, S.; Ovenshine, A.T.; Kachadoorian, R.

    1983-01-01

    Records four prograding cycles of estuarine deposition for the past 8230 + or - 100 years. Analyses of texture, mineralogy, paleontology, and sedimentary structures enable definition of eight lithologic units. Mineralogic studies show that past and present sedimentation at Portage has been largely mud and sand from the Susitna River on the NW side of Cook Inlet. Sedimentation rates for four intervals show rates to be higher and to vary more at depth than rates nearer the surface. Presently, deposition is accomplished 'instantly' as the result of tectonic subsidence and compaction of sediment caused by periodic earthquakes, in combination with a turbid estuarine system. -from Authors

  13. The Southern Argentina Agile MEteor Radar Orbital System (SAAMER-OS): An Initial Sporadic Meteoroid Orbital Survey in the Southern Sky

    NASA Astrophysics Data System (ADS)

    Janches, D.; Close, S.; Hormaechea, J. L.; Swarnalingam, N.; Murphy, A.; O'Connor, D.; Vandepeer, B.; Fuller, B.; Fritts, D. C.; Brunini, C.

    2015-08-01

    We present an initial survey in the southern sky of the sporadic meteoroid orbital environment obtained with the Southern Argentina Agile MEteor Radar (SAAMER) Orbital System (OS), in which over three-quarters of a million orbits of dust particles were determined from 2012 January through 2015 April. SAAMER-OS is located at the southernmost tip of Argentina and is currently the only operational radar with orbit determination capability providing continuous observations of the southern hemisphere. Distributions of the observed meteoroid speed, radiant, and heliocentric orbital parameters are presented, as well as those corrected by the observational biases associated with the SAAMER-OS operating parameters. The results are compared with those reported by three previous surveys performed with the Harvard Radio Meteor Project, the Advanced Meteor Orbit Radar, and the Canadian Meteor Orbit Radar, and they are in agreement with these previous studies. Weighted distributions for meteoroids above the thresholds for meteor trail electron line density, meteoroid mass, and meteoroid kinetic energy are also considered. Finally, the minimum line density and kinetic energy weighting factors are found to be very suitable for meteroid applications. The outcomes of this work show that, given SAAMER’s location, the system is ideal for providing crucial data to continuously study the South Toroidal and South Apex sporadic meteoroid apparent sources.

  14. The 2014-2015 warming anomaly in the Southern California Current System observed by underwater gliders

    NASA Astrophysics Data System (ADS)

    Zaba, Katherine D.; Rudnick, Daniel L.

    2016-02-01

    Large-scale patterns of positive temperature anomalies persisted throughout the surface waters of the North Pacific Ocean during 2014-2015. In the Southern California Current System, measurements by our sustained network of underwater gliders reveal the coastal effects of the recent warming. Regional upper ocean temperature anomalies were greatest since the initiation of the glider network in 2006. Additional observed physical anomalies included a depressed thermocline, high stratification, and freshening; induced biological consequences included changes in the vertical distribution of chlorophyll fluorescence. Contemporaneous surface heat flux and wind strength perturbations suggest that local anomalous atmospheric forcing caused the unusual oceanic conditions.

  15. EFFECT OF DIFLUBENZURON ON AN ESTUARINE CRUSTACEAN

    EPA Science Inventory

    Data are reported for tests exposing a small, estuarine crustacean, Mysidopsis bahia, to diflubenzuron (Dimilin, TH-6040, (1-(4-chlorophenyl)-3-(2,6-difluorobenzoyl)urea)) in flowing seawater. Tests were conducted in intermittent flows from a diluter or continuous flowing water i...

  16. Estuarine Oceanography. CEGS Programs Publication Number 18.

    ERIC Educational Resources Information Center

    Wright, F. F.

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

  17. Eddy Surface properties and propagation at Southern Hemisphere western boundary current systems

    NASA Astrophysics Data System (ADS)

    Pilo, G. S.; Mata, M. M.; Azevedo, J. L. L.

    2015-02-01

    Oceanic eddies occur in all world oceans, but are more energetic when associated to western boundary currents (WBC) systems. In these regions, eddies play an important role on mixing and energy exchange. Therefore, it is important to quantify and qualify eddies occurring within these systems. Previous studies performed eddy censuses in Southern Hemisphere WBC systems. However, important aspects of local eddy population are still unknown. Main questions to be answered relate to eddies' spatial distribution, propagation and lifetime within each system. Here, we use a global eddy dataset to qualify eddies based on their surface characteristics at the Agulhas Current (AC), the Brazil Current (BC) and the East Australian Current (EAC) Systems. We show that eddy propagation within each system is highly forced by the local mean flow and bathymetry. In the AC System, eddy polarity dictates its propagation distance. BC system eddies do not propagate beyond the Argentine Basin, and are advected by the local ocean circulation. EAC System eddies from both polarities cross south of Tasmania, but only anticyclonics reach the Great Australian Bight. Eddies in all systems and from both polarities presented a geographical segregation according to size. Large eddies occur along the Agulhas Retroflection, the Agulhas Return Current, the Brazil-Malvinas Confluence and the Coral Sea. Small eddies occur in the systems southernmost domains. Understanding eddies' propagation helps to establish monitoring programs, and to better understand how these features would affect local mixing.

  18. Evolution of Paleogene submarine Canyon-Fan systems, southern Sacramento basin, California

    SciTech Connect

    Fischer, P.J.; Cherven, V.B.; Almgren, A.A.

    1986-04-01

    The evolutionary development of the Paleogene Martinez and Meganos Submarine Canyon and Fan systems of the southern Sacramento basin was controlled by a complex interplay of eustatic sea level change and tectonism. In this brief synthesis, the authors postulated that eustatic sea level changes were the dominant or controlling factor, and tectonism, although significant, was of secondary importance. The development of the Paleogene canyon and fan systems is correlated with low sea level stands or regressions at 60 Ma and 56 Ma. Intermittent tectonism, beginning at least 5-10 m.y. earlier, particularly along the western and southwestern margins of the Sacramento basin, controlled the location of the canyon and fan systems. The controlling tectonic elements of the southern basin were north-trending, high-angle faults related to the Kirby Hills and Midland fault zones and the Diablo-Kirby Hills(.) uplift. Both canyons were probably active (that is, channeling coarse sediment to their fans) during most of the late Paleocene. The authors suggest that canyon activity was maintained by south-flowing longshore drift or feeder systems, down-canyon gravity flows (turbidites, etc) and up-down canyon current systems, all of which are typical of modern, active submarine canyon and fan systems. The canyons filled with fine-grained sediments when the canyons were beheaded or separated from the longshore drift system by rising sea level, or when tectonism(.) shifted the major river drainage that supplied the canyon with sediment. Truncation and erosion of the canyon-fill and fan facies of the late Paleocene-early Eocene Meganos Formation along the Diablo outcrop belt was primarily due to the major early middle Eocene lowstand (49.5 Ma).

  19. Duplex development and abandonment during evolution of the Lewis thrust system, southern Glacier National Park, Montana

    NASA Astrophysics Data System (ADS)

    Yin, An; Kelty, Thomas K.; Davis, Gregory A.

    1989-09-01

    Geologic mapping in southern Glacier National Park, Montana, reveals the presence of two duplexes sharing the same floor thrust fault, the Lewis thrust. The westernmost duplex (Brave Dog Mountain) includes the low-angle Brave Dog roof fault and Elk Mountain imbricate system, and the easternmost (Rising Wolf Mountain) duplex includes the low-angle Rockwell roof fault and Mt. Henry imbricate system. The geometry of these duplexes suggests that they differ from previously described geometric-kinematic models for duplex development. Their low-angle roof faults were preexisting structures that were locally utilized as roof faults during the formation of the imbricate systems. Crosscutting of the Brave Dog fault by the Mt. Henry imbricate system indicates that the two duplexes formed at different times. The younger Rockwell-Mt. Henry duplex developed 20 km east of the older Brave Dog-Elk Mountain duplex; the roof fault of the former is at a higher structural level. Field relations confirm that the low-angle Rockwell fault existed across the southern Glacier Park area prior to localized formation of the Mt. Henry imbricate thrusts beneath it. These thrusts kinematically link the Rockwell and Lewis faults and may be analogous to P shears that form between two synchronously active faults bounding a simple shear system. The abandonment of one duplex and its replacement by another with a new and higher roof fault may have been caused by (1) warping of the older and lower Brave Dog roof fault during the formation of the imbricate system (Elk Mountain) beneath it, (2) an upward shifting of the highest level of a simple shear system in the Lewis plate to a new decollement level in subhorizontal belt strata (= the Rockwell fault) that lay above inclined strata within the first duplex, and (3) a reinitiation of P-shear development (= Mt. Henry imbricate faults) between the Lewis thrust and the subparallel, synkinematic Rockwell fault.

  20. Transport of persistent organic pollutants by microplastics in estuarine conditions

    NASA Astrophysics Data System (ADS)

    Bakir, Adil; Rowland, Steven J.; Thompson, Richard C.

    2014-03-01

    Microplastics represent an increasing source of anthropogenic contamination in aquatic environments, where they may also act as scavengers and transporters of persistent organic pollutants. As estuaries are amongst the most productive aquatic systems, it is important to understand sorption behaviour and transport of persistent organic pollutants (POPs) by microplastics along estuarine gradients. The effects of salinity sorption equilibrium kinetics on the distribution coefficients (Kd) of phenanthrene (Phe) and 4,4‧-DDT, onto polyvinyl chloride (PVC) and onto polyethylene (PE) were therefore investigated. A salinity gradient representing freshwater, estuarine and marine conditions, with salinities corresponding to 0 (MilliQ water, 690 μS/cm), 8.8, 17.5, 26.3 and 35 was used. Salinity had no significant effect on the time required to reach equilibrium onto PVC or PE and neither did it affect desorption rates of contaminants from plastics. Although salinity had no effect on sorption capacity of Phe onto plastics, a slight decrease in sorption capacity was observed for DDT with salinity. Salinity had little effect on sorption behaviour and POP/plastic combination was shown to be a more important factor. Transport of Phe and DDT from riverine to brackish and marine waters by plastic is therefore likely to be much more dependent on the aqueous POP concentration than on salinity. The physical characteristics of the polymer and local environmental conditions (e.g. plastic density, particle residence time in estuaries) will affect the physical transport of contaminated plastics. A transport model of POPs by microplastics under estuarine conditions is proposed. Transport of Phe and DDT by PVC and PE from fresh and brackish water toward fully marine conditions was the most likely net direction for contaminant transport and followed the order: Phe-PE >> DDT-PVC = DDT-PE >> Phe-PVC.

  1. A CASE STUDY OF LAND DEGRADATION LINKING BIOPHYSICAL AND SOCIOECONOMIC ASPECTS OF AGROECOLOGICAL PRODUCTION SYSTEMS IN SOUTHERN HONDURAS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Dahlem Desertification Protocol (DDP) was developed to analyze interrelationships within coupled human-environment systems. In this study, we apply the DDP to humid systems through an evaluation of an innovative agroecological production system in the mountains of southern Honduras, where season...

  2. EXPECTED EFFECTS OF RESIDUAL CHLORINE AND NITROGEN IN SEWAGE EFFLUENT ON THE ESTUARINE ECOSYSTEM OF GREENWICH COVE, RI: AN ENERGY SYSTEMS AND RISK ASSESSMENT OF EFFECTS

    EPA Science Inventory

    Physical, toxicological, and energy systems modeling were combined to make estimates of likely ecosystem-level effects due to residual chlorine in sewage effluent. The energy systems model also allowed us to make estimates of the effects of nutrient loading on the estuary both se...

  3. The live bird market system and low-pathogenic avian influenza prevention in southern California.

    PubMed

    Yee, Karen S; Carpenter, Tim E; Mize, Sarah; Cardona, Carol J

    2008-06-01

    Although live bird markets (LBMs) have been associated with outbreaks of avian influenza (AI), there are some LBM systems where AI outbreaks are extremely rare events. The California LBMs have not had any detected avian influenza viruses (AIVs) since December 2005. Responses to a detailed questionnaire on the practices and characteristics of the participants in the California low-pathogenic (LP) AI control program have been described to characterize possible reasons for the lack of AI outbreaks in LBMs. Compliance with an LPAI control program that contains active surveillance, prevention, and rapid response measures by those involved in the LBM system, rendering services to dispose of carcasses, no wholesalers, and few third-party bird deliveries was associated with the lack of LPAIV circulating in the Southern California LBM system. PMID:18646469

  4. INTERACTIONS BETWEEN THYROID AND CORTICOSTEROID SYSTEMS DURING THE EARLY LIFE HISTORY OF AN ESTUARINE DEPENDENT FISH: A POSSIBLE TARGET FOR ENDOCRINE DISRUPTION BY ATRAZINE

    EPA Science Inventory

    This research will determine whether interactions between the thyroid and corticosteroid systems are consistent throughout the early life history of marine fish, or whether such interactions vary during development. This study will indicate whether endocrine related gene expr...

  5. A Comparative Ecological Approach to Assess the Role of Watersheds in Estuarine Condition

    EPA Science Inventory

    Estuarine condition is a function of the geophysical nature of the estuary, the ocean (and atmospheric) system, and the upstream watershed. To fully understand and predict how an estuary will respond to a mixture of natural and anthropogenic drivers and pressures each compartment...

  6. The Role of Watershed Characteristics in Estuarine Condition: An Empirical Approach

    EPA Science Inventory

    Estuarine condition is a function of the nature of the estuary, ocean, and atmospheric systems, and the upstream watershed. To fully understand and predict how an estuary will respond to drivers and pressures, each compartment must be characterized. For example, eutrophication ef...

  7. Comparative Ecological Approach to Assess the Role of Watersheds in Estuarine Condition

    EPA Science Inventory

    Estuarine condition is a function of the nature of the estuary, ocean, and atmospheric systems, and the upstream watershed. To fully understand and predict how an estuary will respond to drivers and pressures, each compartment must be characterized. For example, eutrophication ef...

  8. OVERVIEW OF SAFETY OF MICROBIAL INSECTICIDES TO ESTUARINE AND MARINE ORGANISMS

    EPA Science Inventory

    The chapter presents an overview of safety tests of microbial insecticides to estuarine and marine organisms that have been performed to date. Approaches and experimental design, species of MPCAs tested, systems used, and endpoints and results evaluated for determination of risks...

  9. Using stable isotopes and models to explore estuarine linkages at multiple scales

    EPA Science Inventory

    Estuarine managers need tools to respond to dynamic stressors that occur in three linked environments – coastal ocean, estuaries and watersheds. Models have been the tool of choice for examining these dynamic systems because they simplify processes and integrate over multiple sc...

  10. Simulating effects of highway embankments on estuarine circulation

    USGS Publications Warehouse

    Lee, Jonathan K.; Schaffranek, Raymond W.; Baltzer, Robert A.

    1994-01-01

    A two-dimensional depth-averaged, finite-difference, numerical model was used to simulate tidal circulation and mass transport in the Port Royal Sound. South Carolina, estuarine system. The purpose of the study was to demonstrate the utility of the Surface-Water. Integrated. Flow and Transport model (SWIFT2D) for evaluating changes in circulation patterns and mass transport caused by highway-crossing embankments. A model of subregion of Port Royal Sound including the highway crossings and having a grid size of 61 m (200ft) was derived from a 183-m (600-ft) model of the entire Port Royal Sound estuarine system. The 183-m model was used to compute boundary-value data for the 61-m submodel, which was then used to simulate flow conditions with and without the highway embankments in place. The numerical simulations show that, with the highway embankment in place, mass transport between the Broad River and Battery Creek is reduced and mass transport between the Beaufort River and Battery Creek is increased. The net result is that mass transport into and out of upper Battery Creek is reduced. The presence of the embankments also alters circulation patterns within Battery Creek.

  11. STRONG SELECTIVE SIGNAL AND HIGH GENETIC VARIABILITY AT AN IMMUNE SYSTEM LOCUS IN CONTAMINATED AND UNCONTAMINATED POPULATIONS OF AN ESTUARINE FISH

    EPA Science Inventory

    The major histocompatibility complex (MHC) is a group of linked genes that mediates the adaptive immune response in vertebrates. Studies using mammals and birds have shown that environmental stressors can produce genetic changes at MHC loci that can affect immune system function....

  12. Modelling the sensitivity of coastal winds over the Southern Benguela upwelling system to different SST forcing

    NASA Astrophysics Data System (ADS)

    Burls, N.; Reason, C. J. C.

    2008-11-01

    Regional atmospheric modeling has been utilised in an attempt to resolve mesoscale spatial variations in wind stress forcing over the southern Benguela. The regional atmospheric model MM5 was used to simulate low-level coastal winds at high resolution (3 km) over the southern Benguela upwelling system for the March 2001 period and to assess the sensitivity to different resolution sea surface temperature (SST) forcing. The ability of a regional atmospheric model to resolve the mesoscale spatial variability in the local wind field which results from the adjustment of the large scale flow to regional topography and thermal gradients is demonstrated. The model output has been validated quantitatively through comparison with limited observations and qualitatively through comparison with wind fields observed in aircraft surveys conducted during previous summers. The regional model was capable of reproducing the qualitative effect of topographic forcing and thermal gradients on the equatorward flow. Local enhancement of low-level wind speed due to the interaction of the synoptic equatorward flow with both the Cape Peninsula and Cape Columbine was reproduced with associated bands of wind maxima, while lighter winds were seen in the lee of these capes. Increasing the spatial resolution of SST forcing to resolve cold SST's induced by upwelling is seen to enhance the mean response of low-level winds to coastal topography during the March 2001 event. These wind variations have important implications for coastal ocean dynamics and the development of extreme events in the region such as harmful algal blooms.

  13. Drought risk assessments of water resources systems under climate change: a case study in Southern Taiwan

    NASA Astrophysics Data System (ADS)

    Yang, T. C.; Chen, C.; Kuo, C. M.; Tseng, H. W.; Yu, P. S.

    2012-11-01

    This study aims at assessing the impact of climate change on drought risk in a water resources system in Southern Taiwan by integrating the weather generator, hydrological model and simulation model of reservoir operation. Three composite indices with multi-aspect measurements of reservoir performance (i.e. reliability, resilience and vulnerability) were compared by their monotonic behaviors to find a suitable one for the study area. The suitable performance index was then validated by the historical drought events and proven to have the capability of being a drought risk index in the study area. The downscaling results under A1B emission scenario from seven general circulation models were used in this work. The projected results show that the average monthly mean inflows during the dry season tend to decrease from the baseline period (1980-1999) to the future period (2020-2039); the average monthly mean inflows during the wet season may increase/decrease in the future. Based on the drought risk index, the analysis results for public and agricultural water uses show that the occurrence frequency of drought may increase and the severity of drought may be more serious during the future period than during the baseline period, which makes a big challenge on water supply and allocation for the authorities of reservoir in Southern Taiwan.

  14. Sorghum and legume intercropping to improve resource use efficiency of forage production systems in the Southern High Plains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Declining water resources and the presence of large dairy and beef facilities in the Southern High Plains necessitates improving efficiency of forage production system to sustain irrigated agriculture in the region. Delayed inhabitance of interrow space by annual row cropping systems leads to ineffi...

  15. Hydrological mixing and geochemical processes characterization in an estuarine/mangrove system using environmental tracers in Babitonga Bay (Santa Catarina, Brazil)

    NASA Astrophysics Data System (ADS)

    Barros Grace, Virgínia; Mas-Pla, Josep; Oliveira Novais, Therezinha; Sacchi, Elisa; Zuppi, Gian Maria

    2008-03-01

    The hydrologic complex of Babitonga Bay (Brazil) forms a vast environmental complex where agriculture, shellfish farming, and industries coexist with a unique natural area of Atlantic rain forest and mangrove systems. The origin of different continental hydrological components, the environmental transition between saline and freshwaters, and the influence of the seasonality on Babitonga Bay waters are evaluated using isotopes and chemistry. End-member mixing analysis is used to explore hydrological processes in the bay. We show that a mixing of waters from different origins takes place in the bay modifying its chemical characteristics. Furthermore, biogeochemical processes related to well-developed mangrove systems are responsible for an efficient bromide uptake, which limit its use as a tracer as commonly used in non-biologically active environments. Seasonal behaviours are also distinguished from our datasets. The rainy season (April) provides a homogenization of the hydrological processes that is not seen after the dry season (October), when larger spatial differences appear and when the effects of biological processes on the bay hydrochemistry are more dynamic, or can be better recognized. Moreover, Cl/Br and stable isotopes of water molecule allow a neat definition of the hydrological and biogeochemical processes that control chemical composition in coastal and transition areas.

  16. Temporally intensive study of trace metals in sediments and bivalves from a large river-estuarine system: Suisun Bay/delta in San Francisco Bay

    USGS Publications Warehouse

    Luoma, S.N.; Dagovitz, R.; Axtmann, E.

    1990-01-01

    Distributions in time and space of Ag, Cd, Cr, Cu, Pb and Zn were determined in fine-grained sediments and in the filter-feeding bivalve Corbicula sp. of Suisun Bay/delta at the mouth of the Sacramento and San Joaquin Rivers in North San Francisco Bay. Samples were collected from seven stations at near-monthly intervals for 3 years. Aggregated data showed little chronic contamination with Ag, Zn and Pb in the river and estuary. Substantial chronic contamination with Cd, Cu and Cr in Suisun Bay/delta occurred, especially in Corbicula, compared with the lower San Joaquin River. Salinity appeared to have secondary effects, if any, on metal concentrations in sediments and metal bioavailability to bivalves. Space/time distributions of Cr were controlled by releases from a local industry. Analyses of time series suggested substantial inputs of Cu might originate from the Sacramento River during high inflows to the Bay, and Cd contamination had both riverine and local sources. Concentrations of metals in sediments correlated with concentrations in Corbicula only in annually or 3-year aggregated data. Condition index for Corbicula was reduced where metal contamination was most severe. The biological availability of Cu and Cd to benthos was greater in Suisun Bay than in many other estuaries. Thus small inputs into this system could have greater impacts than might occur elsewhere; and organisms were generally more sensitive indicators of enrichment than sediments in this system.

  17. Improving the seismic imaging in the southern Ryukyu subduction system by using multiple attenuation methods

    NASA Astrophysics Data System (ADS)

    Lyu, Ci-Jhu; Kuo-Chen, Hao; McIntosh, Kirk; Wu, Francis; Liu, Char-Shine

    2015-04-01

    The southern Ryukyu subduction system is at the boundary where the Philippine sea plate subducts northwestward beneath the Eurasian plate near the Taiwan orogen. In previous studies, the boundary where the PSP subducts northward beneath the EP have no clear answers due to a lack of high-resolution crustal-scale geophysical constraints. We want to know the Moho boundary. We analyze in this study the dynamics of SRA system with TAIGER program of 2009, multi-channel marine seismic reflection (MGL0906_23, MGL0906_28, MGL0906_26A, MGL0906_13, MGL0906_18N). Data area covers about 30,000 km2. Shots are spaced every 50 m, hydrophones are spaced every 12.5 m, and CDP spacing is 6.25 m. Recording length is 15 s. Signal of the source is low frequencies (20Hz~60Hz), which can penetrate the shallow sediments and reflex signal of the deep crust. Because multiple can affect the deep structure signals. Therefore, we use a variety of methods to remove multiple effects, and increase Moho signals. In this study, we use four ways to remove the multiple. (1) Increases CDP spacing. (2)Deconvolution. (3) Surface Related Multiple Elimination (SRME). (4)Radon Transform multiple attenuation. From the TAIGER marine reflection data. The shallow structure are Huatung Basin, Yeyama Accretionary Prism, Forearc Basin and Ryukyu Arc (from south to north), respectively. We discover a lot of transform fault zone, and account these stress related with shear zone of Ryukyu subduction system. The deep structure, the crust of PSP velocity is about 5~7 km/s, the PSP Moho velocity is 7.5 km/s. In multichannel reflection seismic, the PSP Moho deep is about 15~20 km under the seabed. Keywords: multiple; Moho boundary; subduction zone; southern Ryukyu Arc (SRA)

  18. Assessment of the zinc diffusion rate in estuarine zones.

    PubMed

    Sámano, María Luisa; Pérez, María Luisa; Claramunt, Inigo; García, Andrés

    2016-03-15

    Industrial pressures suffered by estuarine zones leave a pollution record in their sediment. Thus, high concentrations of many heavy metals and some organic compounds are often found in estuarine sediment. This work aims to contribute to the enhancement of water quality management strategies in these zones by studying in detail the diffusive processes that take place between the water and sediment using a two-pronged approach: experimental practice and numerical simulation. To provide an example of the practical application of the methodologies proposed in this paper, the Suances Estuary (northern Spain) was selected as the study zone. This estuary exhibits significant historical pollution and its sediment acts as a continuous internal source of zinc, mainly due to diffusive processes derived from the concentration gradient between the interstitial water at the solid particles of the sediment and the bottom of the water column. The experimentally obtained results, based on 6 case studies, demonstrated the buffering capacity of the system and allowed the determination of the required time for the mass transfer processes to reach an equilibrium state. Furthermore, the diffusion rate of zinc was approximately modeled taking into consideration the high concentration variability observed in sediment along the entire estuary. The convergence between the modeled and the experimental results indicated the required contact time to reach an equilibrium state in a real field situation. PMID:26851870

  19. Movement of spilled oil as predicted by estuarine nontidal drift

    USGS Publications Warehouse

    Conomos, T.J.

    1975-01-01

    Information on water movement obtained from bimonthly releases of surface and seabed drifters in the San Francisco Bay and adjacent Pacific Ocean is used to understand major processes controlling dispersal of oil after a spill of 3,200 m3 of Bunker C in the bay in January 1971. River-induced nontidal estuarine circulation was the dominant factor controlling net movement of the oil spilled at the entrance of the bay system, reinforcing ebbing tidal currents and causing the seaward movement of floating oil, which followed paths taken by surface drifters released 3 weeks before the spill. In contrast, some oil formed globules which sank to the near-bottom waters, had the same relative buoyancy as seabed drifters, and moved similarly, beaching in eastern San Pablo Bay after being transported landward in the near-bottom waters. No oil or surface drifters floated into the south bay because surface waters were drifting seaward, away from the south bay. Notable seasonally modulated phenomena which must be considered in predicting surface and near-bottom oil drifts of future spills include a summer (low-river discharge period) diminution of the estuarine circulation mechanism in the north and central bayadjacent ocean region and a seasonal reversal in two-layer drift in the south bay.

  20. The role of nutrient loading and eutrophication in estuarine ecology.

    PubMed Central

    Pinckney, J L; Paerl, H W; Tester, P; Richardson, T L

    2001-01-01

    Eutrophication is a process that can be defined as an increase in the rate of supply of organic matter (OM) to an ecosystem. We provide a general overview of the major features driving estuarine eutrophication and outline some of the consequences of that process. The main chemical constituent of OM is carbon (C), and therefore rates of eutrophication are expressed in units of C per area per unit time. OM occurs in both particulate and dissolved forms. Allochthonous OM originates outside the estuary, whereas autochthonous OM is generated within the system, mostly by primary producers or by benthic regeneration of OM. The supply rates of limiting nutrients regulate phytoplankton productivity that contributes to inputs of autochthonous OM. The trophic status of an estuary is often based on eutrophication rates and can be categorized as oligotrophic (<100 g C m(-2) y(-1), mesotrophic (100-300 g C m(-2) y(-1), eutrophic (300-500 g C m(-2) y(-1), or hypertrophic (>500 g C m(-2) y(-1). Ecosystem responses to eutrophication depend on both export rates (flushing, microbially mediated losses through respiration, and denitrification) and recycling/regeneration rates within the estuary. The mitigation of the effects of eutrophication involves the regulation of inorganic nutrient (primarily N and P) inputs into receiving waters. Appropriately scaled and parameterized nutrient and hydrologic controls are the only realistic options for controlling phytoplankton blooms, algal toxicity, and other symptoms of eutrophication in estuarine ecosystems. PMID:11677178

  1. Performance assessment of separate and combined sewer systems in metropolitan areas in Southern China.

    PubMed

    Li, Tian; Zhang, Wei; Feng, Cang; Shen, Jun

    2014-01-01

    To assess the performance of urban drainage systems in metropolitan areas in southern China, 12 urban drainage systems, including nine separate sewer systems (SSSs) and three combined sewer systems (CSSs) were monitored from 2008 to 2012 in Shanghai and Hefei. Illicit connection rates of SSS were determined. The results indicate that serious illicit connections exist for most SSSs. Annual volume balance for two SSSs with serious illicit connection was assessed with a hydraulic model to determine the dry weather overflow volume. Although interception facilities have been implemented in SSSs, for some systems with serious illicit connections, a considerable volume of dry weather overflow still existed. Combined with monitoring of dry/wet weather flow quality, the pollutant load caused by wet/dry weather overflow was quantified. The results revealed that there was no obvious advantage of having SSSs over CSSs in terms of pollutant control. The serious pollution caused by illicit connections and insufficient management occurs in many cities in China. The performance assessment of separate and CSSs in Shanghai and Hefei provides important lessons and practical experience that can be applied to the construction and management of urban drainage system in China as well as other developing countries. PMID:24473315

  2. 75 FR 69399 - Evaluation of State Coastal Management Programs and National Estuarine Research Reserves

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-12

    ... National Estuarine Research Reserves AGENCY: National Oceanic and Atmospheric Administration (NOAA), Office... Chesapeake Bay (Maryland) National Estuarine Research Reserves. The Coastal Zone Management Program... terms of financial assistance awards funded under the CZMA. The National Estuarine Research...

  3. 76 FR 14376 - Evaluation of State Coastal Management Programs and National Estuarine Research Reserves

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-16

    ... National Estuarine Research Reserves AGENCY: National Oceanic and Atmospheric Administration (NOAA), Office... its intent to evaluate the performance of the ACE Basin (South Carolina) National Estuarine Research Reserve and the Georgia Coastal Management Program. The National Estuarine Research Reserve...

  4. Detrital diversity influences estuarine ecosystem performance.

    PubMed

    Kelaher, Brendan P; Bishop, Melanie J; Potts, Jaimie; Scanes, Peter; Skilbeck, Greg

    2013-06-01

    Global losses of seagrasses and mangroves, eutrophication-driven increases in ephemeral algae, and macrophyte invasions have impacted estuarine detrital resources. To understand the implications of these changes on benthic ecosystem processes, we tested the hypotheses that detrital source richness, mix identity, and biomass influence benthic primary production, metabolism, and nutrient fluxes. On an estuarine muddy sandflat, we manipulated the availability of eight detrital sources, including mangrove, seagrass, and invasive and native algal species that have undergone substantial changes in distribution. Mixes of these detrital sources were randomly assigned to one of 12 treatments and dried detrital material was added to seventy-two 0.25 m(2) plots (n = 6 plots). The treatments included combinations of either two or four detrital sources and high (60 g) or low (40 g) levels of enrichments. After 2 months, the dark, light, and net uptake of NH4 (+) , dissolved inorganic nitrogen, and the dark efflux of dissolved organic nitrogen were each significantly influenced by the identity of detrital mixes, rather than detrital source richness or biomass. However, gross and net primary productivity, average oxygen flux, and net NOX and dissolved inorganic phosphorous fluxes were significantly greater in treatments with low than with high detrital source richness. These results demonstrate that changes in detrital source richness and mix identity may be important drivers of estuarine ecosystem performance. Continued impacts to estuarine macrophytes may, therefore, further alter detritus-fueled productivity and processes in estuaries. Specific tests that address predicted future changes to detrital resources are required to determine the consequences of this significant environmental problem. PMID:23505131

  5. Estuarine turbidity, flushing, salinity, and circulation

    NASA Technical Reports Server (NTRS)

    Pritchard, D. W.

    1972-01-01

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

  6. Physiochemical Evidence of Faulting Processes and Modeling of Fluid in Evolving Fault Systems in Southern California

    SciTech Connect

    Boles, James

    2013-05-24

    Our study targets recent (Plio-Pleistocene) faults and young (Tertiary) petroleum fields in southern California. Faults include the Refugio Fault in the Transverse Ranges, the Ellwood Fault in the Santa Barbara Channel, and most recently the Newport- Inglewood in the Los Angeles Basin. Subsurface core and tubing scale samples, outcrop samples, well logs, reservoir properties, pore pressures, fluid compositions, and published structural-seismic sections have been used to characterize the tectonic/diagenetic history of the faults. As part of the effort to understand the diagenetic processes within these fault zones, we have studied analogous processes of rapid carbonate precipitation (scaling) in petroleum reservoir tubing and manmade tunnels. From this, we have identified geochemical signatures in carbonate that characterize rapid CO2 degassing. These data provide constraints for finite element models that predict fluid pressures, multiphase flow patterns, rates and patterns of deformation, subsurface temperatures and heat flow, and geochemistry associated with large fault systems.

  7. The Impact of Solar Photovoltaic Generation on Balancing Requirements in the Southern Nevada System

    SciTech Connect

    Ma, Jian; Lu, Shuai; Hafen, Ryan P.; Etingov, Pavel V.; Makarov, Yuri V.; Chadliev, Vladimir

    2012-05-07

    Abstract—The impact of integrating large-scale solar photovoltaic (PV) generation on the balancing requirements in terms of regulation and load-following requirements in the southern Nevada balancing area is evaluated. The “swinging door” algorithm and the “probability box” method developed by Pacific Northwest National Laboratory (PNNL) were used to quantify the impact of large PV generation on the balancing requirements of the system operations. The system’s actual scheduling, real-time dispatch and regulation processes were simulated. Different levels of distributed generation were also considered in the study. The impact of hourly solar PV generation forecast errors on regulation and load-following requirements was assessed. The sensitivity of balancing requirements with respect to real-time forecast errors of large PV generation was analyzed. Index Terms—Ancillary services, balancing requirements, load following, regulation, renewables integration, swinging door

  8. Eddy surface properties and propagation at Southern Hemisphere western boundary current systems

    NASA Astrophysics Data System (ADS)

    Pilo, G. S.; Mata, M. M.; Azevedo, J. L. L.

    2015-08-01

    Oceanic eddies exist throughout the world oceans, but are more energetic when associated with western boundary currents (WBC) systems. In these regions, eddies play an important role in mixing and energy exchange. Therefore, it is important to quantify and qualify eddies associated with these systems. This is particularly true for the Southern Hemisphere WBC system where only few eddy censuses have been performed to date. In these systems, important aspects of the local eddy population are still unknown, like their spatial distribution and propagation patterns. Moreover, the understanding of these patterns helps to establish monitoring programs and to gain insight in how eddies would affect local mixing. Here, we use a global eddy data set to qualify eddies based on their surface characteristics in the Agulhas Current (AC), the Brazil Current (BC) and the East Australian Current (EAC) systems. The analyses reveal that eddy propagation within each system is highly forced by the local mean flow and bathymetry. Large values of eddy amplitude and temporal variability are associated with the BC and EAC retroflections, while small values occur in the centre of the Argentine Basin and in the Tasman Sea. In the AC system, eddy polarity dictates the propagation distance. BC system eddies do not propagate beyond the Argentine Basin, and are advected by the local ocean circulation. EAC system eddies from both polarities cross south of Tasmania but only the anticyclonic ones reach the Great Australian Bight. For all three WBC systems, both cyclonic and anticyclonic eddies present a geographical segregation according to radius size and amplitude. Regions of high eddy kinetic energy are associated with the eddies' mean amplitudes, and not with their densities.

  9. Long-term patterns in estuarine fish growth across two climatically divergent regions.

    PubMed

    Doubleday, Zoë A; Izzo, Christopher; Haddy, James A; Lyle, Jeremy M; Ye, Qifeng; Gillanders, Bronwyn M

    2015-12-01

    Long-term ecological datasets are vital for investigating how species respond to changes in their environment, yet there is a critical lack of such datasets from aquatic systems. We developed otolith growth 'chronologies' to reconstruct the growth history of a temperate estuarine fish species, black bream (Acanthopagrus butcheri). Chronologies represented two regions in south-east Australia: South Australia, characterised by a relatively warm, dry climate, and Tasmania, characterised by a relatively cool, wet climate. Using a mixed modelling approach, we related inter-annual growth variation to air temperature, rainfall, freshwater inflow (South Australia only), and El Niño-Southern Oscillation events. Otolith chronologies provided a continuous record of growth over a 13- and 21-year period for fish from South Australia and Tasmania, respectively. Even though fish from Tasmania were sourced across multiple estuaries, they showed higher levels of growth synchronicity across years, and greater year-to-year growth variation, than fish from South Australia, which were sourced from a single, large estuary. Growth in Tasmanian fish declined markedly over the time period studied and was negatively correlated to temperature. In contrast, growth in South Australian fish was positively correlated to both temperature and rainfall. The stark contrast between the two regions suggests that Tasmanian black bream populations are more responsive to regional scale environmental variation and may be more vulnerable to global warming. This study highlights the importance of examining species response to climate change at the intra-specific level and further validates the emerging use of growth chronologies for generating long-term ecological data in aquatic systems. PMID:26245148

  10. An entropy-based surface velocity method for estuarine discharge measurement

    NASA Astrophysics Data System (ADS)

    Bechle, Adam J.; Wu, Chin H.

    2014-07-01

    An entropy-based method is developed to estimate estuarine river discharge from surface velocity measurements. A two-dimensional velocity profile based on the principle of maximum entropy is employed to express the mean velocity as a function of average surface velocity. The entropy-based flow profile is parameterized by the location of maximum velocity in the channel and the shape of the velocity distribution. The entropy parameters are quantified over the tidal cycle to account for the unsteady nature of estuarine flow. The method was tested using experiments conducted at the Danshui River, the largest estuarine system in Taiwan. Surface velocities were measured using an Automated River-Estuary Discharge Imaging System (AREDIS), and full-channel velocity profiles were measured with a moving-boat ADP survey. Entropy parameters were calibrated over the tidal cycle and linearly correlated with the average surface velocity to facilitate estimation from AREDIS measurements. The discharge calculated from average surface velocity and entropy relationships exhibits a 7.7% relative error compared to the ADP velocity profiles. The error nearly doubles when the mean values for entropy parameters are used instead of the variable parameters, indicating the importance of accounting for the unsteady nature of estuarine flows. Furthermore, the effects of measurement coverage area, types of entropy distribution, and wind-induced drift current on the surface velocity-based discharge measurement are evaluated and discussed. Overall, surface velocity measurements in conjunction with the entropy profiles well represent the flow in a complex estuarine environment to provide a reliable estimate of discharge.

  11. Patterns in floral traits and plant breeding systems on Southern Ocean Islands

    PubMed Central

    Lord, Janice M.

    2015-01-01

    The harsh climatic conditions and paucity of potential pollinators on Southern Ocean Islands (SOIs; latitude 46°S–55°S) lead to the expectation that anemophily or self-fertilization are the dominant modes of plant sexual reproduction. However, at least some species have showy inflorescences suggesting biotic pollination or dimorphic breeding systems necessitating cross-pollination. This study investigates whether anemophily and self-compatibility are common on SOIs, whether species or genera with these traits are more widespread or frequent at higher latitudes, and whether gender dimorphy is correlated with anemophily, as might occur if reliance on pollinators was a disadvantage. Of the 321 flowering plant species in the SOI region, 34.3 % possessed floral traits consistent with anemophily. Compatibility information was located for 94 potentially self-fertilizing species, of which 92.6 % were recorded as partially or fully self-compatible. Dioecy occurred in 7.1 % of species overall and up to 10.2 % of island floras, but has not clearly arisen in situ. Gynodioecy occurred in 3.4 % of species. The frequency of anemophily and gender dimorphy did not differ between the SOI flora and southern hemisphere temperate reference floras. At the species level, gender dimorphy was positively associated with fleshy fruit, but at the genus level it was associated with occurrence in New Zealand and a reduced regional distribution. Anemophily was more prevalent in genera occurring on subantarctic islands and the proportion of species with floral traits suggestive of biotic pollination was significantly higher on climatically milder, cool temperate islands. These results support the contention that reliance on biotic pollinators has constrained the distribution of species on SOIs; however, it is also clear that the reproductive biology of few SOI species has been studied in situ and many species likely employ a mixed mating strategy combining biotic pollination with self

  12. Duplex development and abandonment during evolution of the Lewis thrust system, southern Glacier National Park, Montana

    SciTech Connect

    Yin, An; Kelty, T.K.; Davis, G.A. )

    1989-09-01

    The westernmost duplex (Brave Dog Mountain) includes the low-angle Brave Dog roof fault and Elk Mountain imbricate system, and the easternmost (Rising Wolf Mountain) duplex includes the low-angle Rockwell roof fault and Mt. Henry imbricate system. The geometry of these duplexes suggests that they differ from previously described geometric-kinematic models for duplex development. Their low-angle roof faults were preexisting structures that were locally utilized as roof faults during the formation of the imbricate systems. Crosscutting of the Brave Dog fault by the Mt. Henry imbricate system indicates that the two duplexes formed at different times. The younger Rockwell-Mt. Henry duplex developed 20 km east of the older Brave Dog-Elk Mountain duplex; the roof fault of the former is at a higher structural level. Field relations confirm that the low-angle Rockwell fault existed across the southern Glacier Park area prior to localized formation of the Mt. Henry imbricate thrusts beneath it. These thrusts kinematically link the Rockwell and Lewis faults and may be analogous to P shears that form between two synchronously active faults bounding a simple shear system. The abandonment of one duplex and its replacement by another with a new and higher roof fault may have been caused by (1) warping of the older and lower Brave Dog roof fault during the formation of the imbricate system (Elk Mountain) beneath it, (2) an upward shifting of the highest level of a simple shear system in the Lewis plate to a new decollement level in subhorizontal belt strata (= the Rockwell fault) that lay above inclined strata within the first duplex, and (3) a reinitiation of P-shear development (= Mt. Henry imbricate faults) between the Lewis thrust and the subparallel, synkinematic Rockwell fault.

  13. Mapping cattle trade routes in southern Somalia: a method for mobile livestock keeping systems.

    PubMed

    Tempia, S; Braidotti, F; Aden, H H; Abdulle, M H; Costagli, R; Otieno, F T

    2010-12-01

    The Somali economy is the only one in the world in which more than half the population is dependent on nomadic pastoralism. Trade typically involves drovers trekking animals over long distances to markets. A pilot approach for mapping trade routes was undertaken, using the Afmadow to Garissa routes in southern Somalia. The methodology included conducting a workshop with traders to gather preliminary information about the most-used routes and general husbandry practices and training selected drovers to collect data about key features along the routes, using hand-held global positioning system (GPS) devices, radio collar GPS and pictorial data forms. Collected data were then integrated into geographic information systems for analysis. The resultant spatial maps describe the Afmadow to Garissa routes, the speed of livestock movement along these routes and relevant environmental and social features affecting this speed. These data are useful for identifying critical control points for health screening along the routes, which may enable the establishment of a livestock certification system in nomadic pastoral environments. PMID:21309449

  14. Agricultural management systems affect the green lacewing community (Neuroptera: Chrysopidae) in olive orchards in southern Spain.

    PubMed

    Porcel, M; Ruano, F; Cotes, B; Peña, A; Campos, M

    2013-02-01

    Green lacewings are generalist predators whose conservation is important for pest control in olive orchards (Olea europaea L.) Sustainable farming practices, as opposed to conventional management techniques, are believed to foster the presence of natural enemies. This study therefore aims to analyze the effect of 1) herbicidal weed cover removal and insecticide applications, and 2) the general management systems used in the olive orchards of southern Spain on chrysopid assemblages and abundance. Green lacewing adults and larvae were collected from olive orchards under conventional, integrated, and organic management systems. In addition, chemical analyses of residues were carried out to determine the presence of insecticidal and herbicidal residues. Eight adult species and three genera of larvae were identified. No rare species were captured from the most intensively farmed orchard, which therefore recorded the most limited chrysopid diversity with a very marked dominance of Chrysoperla carnea s.l.. No effect of dimethoate treatments on Chrysoperla larvae or C. carnea s.l. adults was observed. However, the presence of insecticide residues was associated with the depletion of Dichochrysa larvae. The absence of herbicide treatments favored C. carnea s.l. adult presence on olive trees while larval abundance decreased. Dichochrysa larvae were more abundant when weed cover received no treatment. In relation to the management systems studied, no difference in Chrysoperla larval abundance was observed between conventional and organic orchards. However, Dichochrysa larvae were more abundant in orchards under organic management. PMID:23339790

  15. An innovative mobile georadar system for road monitoring and diagnostic: first application in Southern Italy

    NASA Astrophysics Data System (ADS)

    Loperte, Antonio; Soldovieri, Francesco; Bavusi, Massimo; Lapenna, Vincenzo; Piscitelli, Sabatino; Valanzano, Antonio; Pafundi, Donato; Lacorazza, Piero

    2013-04-01

    This work will show the preliminary results obtained through the use of an innovative mobile georadar system for road monitoring and diagnostic. This electromagnetic mobile system is an innovative tool which is able to analyse and monitor the road paving of the overall road network with the aim of individuating critical areas affected by sinking or wearing. The georadar system, equipped by a high frequency antenna (f=1GHz), is mounted on a van and is able to acquire suitable data at velocities up to 70Km/hour. Through the use of this kind of mobile system it is possible to obtain in a short time and with very low costs a wide amount of data on thickness and roughness of the asphalt, superficial sinking and water saturated areas. The first tests were carried out on the main provincial road located in an area of the Southern Apennines affected by hydrogeological risk. This activity has been performed in the framework of a project funded by the Province of Potenza, and realized thank to the consolidated collaboration between the Institute of Methodologies for the Environmental Analysis (IMAA) and the Institute for Electromagnetic Sensing of the Environment (IREA) of the National Research Council of Italy (CNR). This activity has been recognized also at European level as a best practice procedure in the frame of "Window on GMES - Global Monitoring for Environment and Security". The application of this innovative electromagnetic system on the overall road system of the province of Potenza will enable the decision-makers to plan with more detail and awareness the technical actions addressed to maintain and repair the road sections really affected by anomalies, with a time-saving and lower management costs.

  16. Modelling the effect of hydrological change on estuarine health: An Australian Perspective. (Invited)

    NASA Astrophysics Data System (ADS)

    Bruce, L. C.; Adiyanti, S.; Ruibal, A. L.; Hipsey, M. R.

    2013-12-01

    Estuaries provide an important role in the filtering and transformation of carbon and nutrients from coastal catchments into the marine environment. Global trends including climate change, increased population, industrialization and agriculture have led to the rapid deterioration of estuarine ecosystems across the world. Within the Australian context, a particular concern is how changes to hydrological regimes, due to both water diversions and climate variability, are contributing to increased stress and consequent decline in estuarine health. In this study we report the modeling output of five Australian estuaries, each with different hydrological regimes and alternative management issues relating to altered hydrology: 1) The Yarra River estuary is a highly urbanized system, also receiving agriculturally derived nutrients, where the concern is the role of periodic hypoxia in reducing the assimilation capacity of nitrogen and thus increased risk of algal blooms forming in the coastal environment; 2) The upper Swan River estuary in Western Australia, which experiences persistent anoxia and hypoxia brought about by reduced flows has led to the commissioning of several oxygenation plants to alleviate stress on biodiversity and overall estuarine health; 3) The health of the Caboolture estuary in Queensland has deteriorated in the past decade with the aim of model development to quantify the various sources of surface and groundwater derived nutrients; 4) The construction of an additional channel to increase flushing in the Peel Harvey estuary in Western Australia was designed to control persistent harmful algal blooms; and 5) The Lower River Murray estuary experienced a prolonged drought that led to the development of acid sulfate soils and acid drainage deteriorating water quality. For these applications we applied 3-D hydrodynamic-biogeochemical models to determine underlying relationships between altered flow regimes, increased temperatures and the response of

  17. Determination of thrust compression systems with a multisource geoscientific data processing in the southern margin of Ordos basin, China

    SciTech Connect

    Yongjie, T.; Genderen, J.L. van

    1996-08-01

    In this paper, the multisource geoscientific data, such as TM data, NOAA data, the data of Bouguer gravity anomaly and aeromagnetic anomaly, the multisource geophysical processing methods, such as upward continuations, vertical derivative and gradient image, and synthetic image processing method - remote sensing image processing and geophysical image processing under I{sup 2}S600, are used to study the reverse faults or thrusts in the southern margin of Ordos basin, China. On the basis of these results and with geological investigation in the field, the authors have determined three thrust compression systems, named EW thrust compression system, NE thrust compression system and NW thrust compression system. These three systems reveal the regularity of geological structural evolution in the southern margin of Ordos basis and in the north side of Qinling Orogenic Belt.

  18. Sources of organic matter for flatfish juveniles in coastal and estuarine nursery grounds: A meta-analysis for the common sole (Solea solea) in contrasted systems of Western Europe

    NASA Astrophysics Data System (ADS)

    Le Pape, O.; Modéran, J.; Beaunée, G.; Riera, P.; Nicolas, D.; Savoye, N.; Harmelin-Vivien, M.; Darnaude, A. M.; Brind'Amour, A.; Le Bris, H.; Cabral, H.; Vinagre, C.; Pasquaud, S.; França, S.; Kostecki, C.

    2013-01-01

    Coastal and estuarine nursery grounds are essential habitats for sustaining flatfish stocks since only these shallow and productive areas provide the high food supply that allows maximizing juvenile growth and survival in most flatfish species. However, the main organic matter sources at the basis of benthic food webs might differ drastically between estuarine nursery grounds under strong freshwater influences, where food webs are mainly supported by continental organic matter, and coastal ecosystems under limited freshwater influence, where the local marine primary production is the main source of carbon for the benthos. To better understand the links between continental inputs to the coastal zone and stock maintenance in the highly prized common sole, Solea solea (L.), we investigated the variability in the organic matter sources supporting the growth of its young-of-the-year (YoY) in five contrasted estuarine and coastal nursery grounds under varying freshwater influence. Stable isotopes of carbon and nitrogen allowed tracing the origin of the organic matter exploited by YoY soles in the very first months following their benthic settlement, i.e. when most of the juvenile mortality occurs in the species. A mixing model was run to unravel and quantify the contribution of all major potential sources of organic matter to sole food webs, with a sensitivity analysis allowing assessment of the impact of various trophic enrichment factors on model outputs. This meta-analysis demonstrated a relative robustness of the estimation of the respective contributions of the various organic matter sources. At the nursery scale, the upstream increase in freshwater organic matter exploitation by YoY soles and its positive correlation with inter-annual variations in the river flow confirmed previous conclusions about the importance of organic matter from continental origin for juvenile production. However, inter-site differences in the organic matter sources exploited for growth

  19. Newport-Inglewood-Carlsbad-Coronado Bank Fault System Nearshore Southern California: Testing models for Quaternary deformation

    NASA Astrophysics Data System (ADS)

    Bennett, J. T.; Sorlien, C. C.; Cormier, M.; Bauer, R. L.

    2011-12-01

    The San Andreas fault system is distributed across hundreds of kilometers in southern California. This transform system includes offshore faults along the shelf, slope and basin- comprising part of the Inner California Continental Borderland. Previously, offshore faults have been interpreted as being discontinuous and striking parallel to the coast between Long Beach and San Diego. Our recent work, based on several thousand kilometers of deep-penetration industry multi-channel seismic reflection data (MCS) as well as high resolution U.S. Geological Survey MCS, indicates that many of the offshore faults are more geometrically continuous than previously reported. Stratigraphic interpretations of MCS profiles included the ca. 1.8 Ma Top Lower Pico, which was correlated from wells located offshore Long Beach (Sorlien et. al. 2010). Based on this age constraint, four younger (Late) Quaternary unconformities are interpreted through the slope and basin. The right-lateral Newport-Inglewood fault continues offshore near Newport Beach. We map a single fault for 25 kilometers that continues to the southeast along the base of the slope. There, the Newport-Inglewood fault splits into the San Mateo-Carlsbad fault, which is mapped for 55 kilometers along the base of the slope to a sharp bend. This bend is the northern end of a right step-over of 10 kilometers to the Descanso fault and about 17 km to the Coronado Bank fault. We map these faults for 50 kilometers as they continue over the Mexican border. Both the San Mateo - Carlsbad with the Newport-Inglewood fault and the Coronado Bank with the Descanso fault are paired faults that form flower structures (positive and negative, respectively) in cross section. Preliminary kinematic models indicate ~1km of right-lateral slip since ~1.8 Ma at the north end of the step-over. We are modeling the slip on the southern segment to test our hypothesis for a kinematically continuous right-lateral fault system. We are correlating four

  20. Ecoengineering with Ecohydrology: Successes and failures in estuarine restoration

    NASA Astrophysics Data System (ADS)

    Elliott, Michael; Mander, Lucas; Mazik, Krysia; Simenstad, Charles; Valesini, Fiona; Whitfield, Alan; Wolanski, Eric

    2016-07-01

    Ecological Engineering (or Ecoengineering) is increasingly used in estuaries to re-create and restore ecosystems degraded by human activities, including reduced water flow or land poldered for agricultural use. Here we focus on ecosystem recolonization by the biota and their functioning and we separate Type A Ecoengineering where the physico-chemical structure is modified on the basis that ecological structure and functioning will then follow, and Type B Ecoengineering where the biota are engineered directly such as through restocking or replanting. Modifying the physical system to create and restore natural processes and habitats relies on successfully applying Ecohydrology, where suitable physical conditions, especially hydrography and sedimentology, are created to recover estuarine ecology by natural or human-mediated colonisation of primary producers and consumers, or habitat creation. This successional process then allows wading birds and fish to reoccupy the rehabilitated areas, thus restoring the natural food web and recreating nursery areas for aquatic biota. We describe Ecohydrology principles applied during Ecoengineering restoration projects in Europe, Australia, Asia, South Africa and North America. These show some successful and sustainable approaches but also others that were less than successful and not sustainable despite the best of intentions (and which may even have harmed the ecology). Some schemes may be 'good for the ecologists', as conservationists consider it successful that at least some habitat was created, albeit in the short-term, but arguably did little for the overall ecology of the area in space or time. We indicate the trade-offs between the short- and long-term value of restored and created ecosystems, the success at developing natural structure and functioning in disturbed estuaries, the role of this in estuarine and wetland management, and the costs and benefits of Ecoengineering to the socio-ecological system. These global case

  1. Coastal and Estuarine Waters: Light Behavior. Coastal and Estuarine Waters: Optical Sensors and Remote Sensing.

    EPA Science Inventory

    This article summarizes the use of remote sensing techniques and technology to monitor coastal and estuarine waters. These waters are rich in mineral particles stirred up from the seabed by tides and waves and dissolved organic matter transported by rivers. The majority of the li...

  2. Shock, Stress or Signal? Implications of Freshwater Flows for a Top-Level Estuarine Predator

    PubMed Central

    Taylor, Matthew D.; van der Meulen, Dylan E.; Ives, Matthew C.; Walsh, Chris T.; Reinfelds, Ivars V.; Gray, Charles A.

    2014-01-01

    Physicochemical variability in estuarine systems plays an important role in estuarine processes and in the lifecycles of estuarine organisms. In particular, seasonality of freshwater inflow to estuaries may be important in various aspects of fish lifecycles. This study aimed to further understand these relationships by studying the movements of a top-level estuarine predator in response to physicochemical variability in a large, temperate south-east Australian estuary (Shoalhaven River). Mulloway (Argyrosomus japonicus, 47–89 cm total length) were surgically implanted with acoustic transmitters, and their movements and migrations monitored over two years via fixed-position VR2W acoustic receivers configured in a linear array along the length of the estuary. The study period included a high degree of abiotic variability, with multiple pulses (exponentially high flows over a short period of time) in fresh water to the estuary, as well as broader seasonal variation in flow, temperature and conductivity. The relative deviation of fish from their modal location in the estuary was affected primarily by changes in conductivity, and smaller fish (n = 4) tended to deviate much further downstream from their modal position in the estuary than larger fish (n = 8). High-flow events which coincided with warmer temperatures tended to drive mature fish down the estuary and potentially provided a spawning signal to stimulate aggregation of adults near the estuary mouth; however, this relationship requires further investigation. These findings indicate that pulse and press effects of freshwater inflow and associated physicochemical variability play a role in the movements of mulloway, and that seasonality of large freshwater flows may be important in spawning. The possible implications of river regulation and the extraction of freshwater for consumptive uses on estuarine fishes are discussed. PMID:24752585

  3. An assessment of landscape characteristics affecting estuarine nitrogen loading in an urban watershed.

    PubMed

    Yang, Xiaojun

    2012-02-01

    Exploring the quantitative association between landscape characteristics and the ecological conditions of receiving waters has recently become an emerging area for eco-environmental research. While the landscape-water relationship research has largely targeted on inland aquatic systems, there has been an increasing need to develop methods and techniques that can better work with coastal and estuarine ecosystems. In this paper, we present a geospatial approach to examine the quantitative relationship between landscape characteristics and estuarine nitrogen loading in an urban watershed. The case study site is in the Pensacola estuarine drainage area, home of the city of Pensacola, Florida, USA, where vigorous urban sprawling has prompted growing concerns on the estuarine ecological health. Central to this research is a remote sensor image that has been used to extract land use/cover information and derive landscape metrics. Several significant landscape metrics are selected and spatially linked with the nitrogen loading data for the Pensacola bay area. Landscape metrics and nitrogen loading are summarized by equal overland flow-length rings, and their association is examined by using multivariate statistical analysis. And a stepwise model-building protocol is used for regression designs to help identify significant variables that can explain much of the variance in the nitrogen loading dataset. It is found that using landscape composition or spatial configuration alone can explain most of the nitrogen loading variability. Of all the regression models using metrics derived from a single land use/cover class as the independent variables, the one from the low density urban gives the highest adjusted R-square score, suggesting the impact of the watershed-wide urban sprawl upon this sensitive estuarine ecosystem. Measures towards the reduction of non-point source pollution from urban development are necessary in the area to protect the Pensacola bay ecosystem and its

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

    PubMed

    Chen, Celia Y; Borsuk, Mark E; Bugge, Deenie M; Hollweg, Terill; Balcom, Prentiss H; Ward, Darren M; Williams, Jason; Mason, Robert P

    2014-01-01

    Methylmercury (MeHg) is a contaminant of global concern that bioaccumulates and bioamagnifies in marine food webs. Lower trophic level fauna are important conduits of MeHg from sediment and water to estuarine and coastal fish harvested for human consumption. However, the sources and pathways of MeHg to these coastal fisheries are poorly known particularly the potential for transfer of MeHg from the sediment to biotic compartments. Across a broad gradient of human land impacts, we analyzed MeHg concentrations in food webs at ten estuarine sites in the Northeast US (from the Hackensack Meadowlands, NJ to the Gulf of Maine). MeHg concentrations in water column particulate material, but not in sediments, were predictive of MeHg concentrations in fish (killifish and Atlantic silversides). Moreover, MeHg concentrations were higher in pelagic fauna than in benthic-feeding fauna suggesting that MeHg delivery to the water column from methylation sites from within or outside of the estuary may be an important driver of MeHg bioaccumulation in estuarine pelagic food webs. In contrast, bulk sediment MeHg concentrations were only predictive of concentrations of MeHg in the infaunal worms. Our results across a broad gradient of sites demonstrate that the pathways of MeHg to lower trophic level estuarine organisms are distinctly different between benthic deposit feeders and forage fish. Thus, even in systems with contaminated sediments, transfer of MeHg into estuarine food webs maybe driven more by the efficiency of processes that determine MeHg input and bioavailability in the water column. PMID:24558491

  5. Benthic and Pelagic Pathways of Methylmercury Bioaccumulation in Estuarine Food Webs of the Northeast United States

    PubMed Central

    Chen, Celia Y.; Borsuk, Mark E.; Bugge, Deenie M.; Hollweg, Terill; Balcom, Prentiss H.; Ward, Darren M.; Williams, Jason; Mason, Robert P.

    2014-01-01

    Methylmercury (MeHg) is a contaminant of global concern that bioaccumulates and bioamagnifies in marine food webs. Lower trophic level fauna are important conduits of MeHg from sediment and water to estuarine and coastal fish harvested for human consumption. However, the sources and pathways of MeHg to these coastal fisheries are poorly known particularly the potential for transfer of MeHg from the sediment to biotic compartments. Across a broad gradient of human land impacts, we analyzed MeHg concentrations in food webs at ten estuarine sites in the Northeast US (from the Hackensack Meadowlands, NJ to the Gulf of Maine). MeHg concentrations in water column particulate material, but not in sediments, were predictive of MeHg concentrations in fish (killifish and Atlantic silversides). Moreover, MeHg concentrations were higher in pelagic fauna than in benthic-feeding fauna suggesting that MeHg delivery to the water column from methylation sites from within or outside of the estuary may be an important driver of MeHg bioaccumulation in estuarine pelagic food webs. In contrast, bulk sediment MeHg concentrations were only predictive of concentrations of MeHg in the infaunal worms. Our results across a broad gradient of sites demonstrate that the pathways of MeHg to lower trophic level estuarine organisms are distinctly different between benthic deposit feeders and forage fish. Thus, even in systems with contaminated sediments, transfer of MeHg into estuarine food webs maybe driven more by the efficiency of processes that determine MeHg input and bioavailability in the water column. PMID:24558491

  6. Major factors influencing the elemental composition of surface estuarine sediments: the case of 15 estuaries in Portugal.

    PubMed

    Mil-Homens, M; Vale, C; Raimundo, J; Pereira, P; Brito, P; Caetano, M

    2014-07-15

    Upper sediments (0-5 cm) were sampled in 94 sites of water bodies of the fifteen Portuguese estuaries characterized by distinct settings of climate, topography and lithology, and marked by diverse anthropogenic pressures. Confined areas recognized as highly anthropogenic impacted, as well as areas dominated by erosion or frequently dredged were not sampled. Grain size, organic carbon (Corg), Al and trace elements (As, Cd, Co, Cr, Cu, Hg, Ni, Pb and Zn) were determined. Normalisation of trace element concentrations to Al and Corg, correlations between elements and Principal Component Analysis (PCA) allowed identifying elemental associations and the relevance of grain-size, lithology and anthropogenic inputs on sediment chemical composition. Whereas grain-size is the dominant effect for the majority of the studied estuaries, the southern estuaries Mira, Arade and Guadiana are dominated by specific lithologies of their river basins, and anthropogenic effects are identified in Ave, Leça, Tagus and Sado. This study emphasizes how baseline values of trace elements in sediments may vary within and among estuarine systems. PMID:24933166

  7. EFFECT OF BARITE (BASO4) ON DEVELOPMENT OF ESTUARINE COMMUNITIES

    EPA Science Inventory

    Barite (BaSO4), the primary component of oil drilling muds, affected the composition of estuarine communities developed from planktonic larvae in aquaria containing sand and flowing estuarine water. Aquaria contained: sand only; a mixture (by volume) of 1 part barite and 10 parts...

  8. Upper Campanian and lower Maestrichtian depositional systems and gas production, southern Sacramento basin, California

    SciTech Connect

    Moore, D.W.; Nilsen, T.H. )

    1990-05-01

    Upper Campanian and lower Maestrichtian strata of the southern Sacramento basin include four west- and southwest-prograding submarine-fan/slope/delta systems. The Winters, Lathrop, Tracy, and Blewett formations consist of submarine-fan and related slope/basin-plain deposits that were fed by various deltaic complexes of the Starkey Formation. Four major basinwide transgressive shale units (Sacramento Shale, Sawtooth Shale, Ragged Valley Shale, and H and T Shale) help intrasystem correlations. The Winters, Tracy, and Blewett fans are small, radial, coalescing sand-rich systems that contain the following principal facies: (1) sandstone-filled inner fan channel deposits, (2) mudstone-dominated inner fan interchannel deposits, (3) middle-fan amalgamated suprafan-type sandstone-rich channel deposits, and (4) mudstone-dominated outer fan deposits. The Lathrop fans are larger, elongate, mixed-sediment systems that contain basin-plain, outer fan lobe, middle fan-channel, levee, interchannel, and inner fan channel facies. The Sierran-derived fluvio-deltaic Starkey Formation can be divided into six sand-rich deltaic cycles that can be subdivided on the basis of log signaturres and spatial distribution into prodelta, delta-front, lower delta-plain, and upper delta-plain/fluvial facies. More than 50 gas fields produce from these systems. Stratigraphic traps include updip pinchouts of submarine canyon/gullies and inner fan channels into slope shale, especially in the many overlapping and coalescing sand-rich systems. Lateral pinchouts of outer fan lobes and middle-fan suprafan-type bodies are also productive. Structural traps generally characterize production from deltaic deposits because of the more continuous nature of these bodies.

  9. Hydrochemical zonation of the western part of Göksu Delta aquifer system, Southern Turkey

    NASA Astrophysics Data System (ADS)

    Dokuz, U. E.; Çelik, M.; Arslan, Ş.; Engin, H.

    2012-04-01

    In general, coastal areas are preferred places for human settlement, especially at places where infrastructure routes benefit from rivers, streets, or harbours. As a result, these areas usually suffer from rising population and endure increasingly high demand on natural resources like water. Göksu Delta, located in southern Turkey, is one of the important wetland areas of Turkey at the Mediterranean coast. It is divided into two parts by Göksu River. The western part of the delta, which is the subject matter of this study, hosts fertile agricultural fields, touristic places and a Special Environmental Protection Area. These properties of the region lead to a water-dependent ecosystem where groundwater has widely been used for agricultural and domestic purposes. When the exploitation of groundwater peaked in the middle of 1990s, the groundwater levels dropped and seawater intruded. General Directorate of State Hydraulic Works tried to stop seawater intrusion by building irrigation channels connected to Göksu River and banned drilling of new wells for groundwater exploitation, although it is hard to control the drilling of wells without official permit. Geological studies show that the delta is composed of terrestrial sediments including clay to coarse sand deposited during Quaternary. The heterogeneous sediments of Göksu Delta cause hydrogeological features of the aquifer systems to be heterogeneous and anisotropic. Hydrogeological investigations, therefore, indicate mainly two different aquifers, shallow and deep, separated by an aquitard. The shallow aquifer is under unconfined to confined conditions from north to south while the deep aquifer is under confined conditions. This study focuses on hydrogeochemical zonation in terms of hydrochemical processes that affect the Göksu Delta aquifer systems. For this purpose, hydrogeochemical and isotopic studies are conducted to understand the salinisation and softening processes of groundwater. The physicochemical

  10. Southern Very Low Mass Stars and Brown Dwarfs in Wide Binary and Multiple Systems

    NASA Astrophysics Data System (ADS)

    Caballero, José Antonio

    2007-09-01

    The results of the Königstuhl survey in the Southern Hemisphere are presented. I have searched for common proper motion companions to 173 field very low mass stars and brown dwarfs with spectral types >M5.0 V and magnitudes J<~14.5 mag. I have measured for the first time the common proper motion of two new wide systems containing very low mass components, Königstuhl 2 AB and 3 A-BC. Together with Königstuhl 1 AB and 2M 0126-50 AB, they are among the widest systems in their respective classes (r=450-11,900 AU). I have determined the minimum frequency of field wide multiples (r>100 AU) with late-type components at 5.0%+/-1.8% and the frequency of field wide late-type binaries with mass ratios q>0.5 at 1.2%+/-0.9%. These values represent a key diagnostic of evolution history and low-mass star and brown dwarf formation scenarios. In addition, the proper motions of 62 field very low mass dwarfs are measured here for the first time.

  11. Hydrological and ecological impacts of dams on the Kafue Flats floodplain system, southern Zambia

    NASA Astrophysics Data System (ADS)

    Mumba, M.; Thompson, J. R.

    Developmental changes in river basins in Africa have become a reality. Many wetland ecosystems have been impacted by dams and other hydrological interventions resulting in both foreseen and unexpected consequences. The Kafue Flats in southern Zambia is an extensive floodplain system that lies within the middle Kafue river basin. The floodplain is about 255 km long and 60 km wide, covering an area of approximately 6,500 km 2. It is currently sandwiched between two large dams which are approximately 270 km apart. These dams have completely altered the hydrological regime of the system. Backwater from the downstream dam and releases from upstream have created a permanently flooded area within the floodplain that was not present in the past. Elsewhere, flooding has been reduced. The ecological consequences of these changes for the floodplain, which hosts two national parks (both Ramsar sites), have been extensive. Hydrological and vegetation changes have impacted the habitat for important wildlife communities including the endemic antelope, Kobus leche kafuensis. The most dramatic change in vegetation is associated with the colonisation of parts of the floodplain by the invasive alien plant, Mimosa pigra. This paper discusses these changes and their potential consequences.

  12. Southern company energy storage study : a study for the DOE energy storage systems program.

    SciTech Connect

    Ellison, James; Bhatnagar, Dhruv; Black, Clifton; Jenkins, Kip

    2013-03-01

    This study evaluates the business case for additional bulk electric energy storage in the Southern Company service territory for the year 2020. The model was used to examine how system operations are likely to change as additional storage is added. The storage resources were allowed to provide energy time shift, regulation reserve, and spinning reserve services. Several storage facilities, including pumped hydroelectric systems, flywheels, and bulk-scale batteries, were considered. These scenarios were tested against a range of sensitivities: three different natural gas price assumptions, a 15% decrease in coal-fired generation capacity, and a high renewable penetration (10% of total generation from wind energy). Only in the elevated natural gas price sensitivities did some of the additional bulk-scale storage projects appear justifiable on the basis of projected production cost savings. Enabling existing peak shaving hydroelectric plants to provide regulation and spinning reserve, however, is likely to provide savings that justify the project cost even at anticipated natural gas price levels. Transmission and distribution applications of storage were not examined in this study. Allowing new storage facilities to serve both bulk grid and transmission/distribution-level needs may provide for increased benefit streams, and thus make a stronger business case for additional storage.

  13. The Earthquake Early Warning System for Southern Italy: Concepts, Capabilities and Future Perspectives

    NASA Astrophysics Data System (ADS)

    Satriano, C.; Elia, L.; Martino, C.; Lancieri, M.; Zollo, A.; Iannaccone, G.

    2009-12-01

    In the framework of earthquake early warning (EEW) experimentation in Southern Italy, we have developed an integrated software platform called PRESTo (PRobabilistic and Evolutionary early warning SysTem). PRESTo is a methodology for regional EEW applications, based on a fully probabilistic and evolutionary approach. This means that probability density functions of source parameters and ground shaking levels are computed , which make possible to evaluate the uncertainties, and to set an appropriate level of reliability of the issued warning. Moreover, the estimates of earthquake location, size and expected ground motion are continuously updated, as new data is available in real-time from the network. The earthquake location algorithm is based on an equal differential time formulation, and a probabilistic framework for describing the hypocenter solution. The algorithm, at each time step, relies on both the information from triggered arrivals and not-yet-triggered stations. The magnitude estimation is based on a Bayesian approach, and exploits an empirical relationship that correlates the final event magnitude with the logarithm of the distance-corrected, peak ground displacement, measured over the first 2÷4 seconds of P- and S-signals. Finally, a ground motion prediction equation valid at regional scale is used to predict the peak velocities and accelerations at the target sites. The core infrastructure of the EEW system in Southern Italy is the high density, wide dynamic-range seismic network ISNet (Irpinia Seismic Network), deployed along the Apennine chain, which is frequently stricken by moderate to large magnitude damaging earthquakes. For earthquakes originating inside the ISNet seismic network, a first alarm can be issued within 4-6 seconds from the origin time, and a stable estimate with relatively small error on location (less than 5 km) and magnitude (about 0.5 magnitude units) is achieved within 10 seconds after the origin time. PRESTo can easily be

  14. Modeling centuries of estuarine morphodynamics in the Western Scheldt estuary

    NASA Astrophysics Data System (ADS)

    Dam, G.; Wegen, M.; Labeur, R. J.; Roelvink, D.

    2016-04-01

    We hindcast a 110 year period (1860-1970) of morphodynamic behavior of the Western Scheldt estuary by means of a 2-D, high-resolution, process-based model and compare results to a historically unique bathymetric data set. Initially, the model skill decreases for a few decades. Against common perception, the model skill increases after that to become excellent after 110 years. We attribute this to the self-organization of the morphological system which is reproduced correctly by the numerical model. On time scales exceeding decades, the interaction between the major tidal forcing and the confinement of the estuary overrules other uncertainties. Both measured and modeled bathymetries reflect a trend of decreasing energy dissipation, less morphodynamic activity, and thus a more stable morphology over time, albeit that the estuarine adaptation time is long (approximately centuries). Process-based models applied in confined environments and under constant forcing conditions may perform well especially on long (greater than decades) time scales.

  15. Applications of remote sensing to estuarine management

    NASA Technical Reports Server (NTRS)

    Munday, J. C., Jr.; Gordon, H. H.; Hennigar, H. F.

    1977-01-01

    Remote sensing was used in the resolution of estuarine problems facing federal and Virginia governmental agencies. A prototype Elizabeth River Surface Circulation Atlas was produced from photogrammetry to aid in oil spill cleanup and source identification. Aerial photo analysis twice led to selection of alternative plans for dredging and spoil disposal which minimized marsh damage. Marsh loss due to a mud wave from a highway dyke was measured on sequential aerial photographs. An historical aerial photographic sequence gave basis to a potential Commonwealth of Virginia legal claim to accreting and migrating coastal islands.

  16. An operational real-time flood forecasting system in Southern Italy

    NASA Astrophysics Data System (ADS)

    Ortiz, Enrique; Coccia, Gabriele; Todini, Ezio

    2015-04-01

    A real-time flood forecasting system has been operating since year 2012 as a non-structural measure for mitigating the flood risk in Campania Region (Southern Italy), within the Sele river basin (3.240 km2). The Sele Flood Forecasting System (SFFS) has been built within the FEWS (Flood Early Warning System) platform developed by Deltares and it assimilates the numerical weather predictions of the COSMO LAM family: the deterministic COSMO-LAMI I2, the deterministic COSMO-LAMI I7 and the ensemble numerical weather predictions COSMO-LEPS (16 members). Sele FFS is composed by a cascade of three main models. The first model is a fully continuous physically based distributed hydrological model, named TOPKAPI-eXtended (Idrologia&Ambiente s.r.l., Naples, Italy), simulating the dominant processes controlling the soil water dynamics, runoff generation and discharge with a spatial resolution of 250 m. The second module is a set of Neural-Networks (ANN) built for forecasting the river stages at a set of monitored cross-sections. The third component is a Model Conditional Processor (MCP), which provides the predictive uncertainty (i.e., the probability of occurrence of a future flood event) within the framework of a multi-temporal forecast, according to the most recent advancements on this topic (Coccia and Todini, HESS, 2011). The MCP provides information about the probability of exceedance of a maximum river stage within the forecast lead time, by means of a discrete time function representing the variation of cumulative probability of exceeding a river stage during the forecast lead time and the distribution of the time occurrence of the flood peak, starting from one or more model forecasts. This work shows the Sele FFS performance after two years of operation, evidencing the added-values that can provide to a flood early warning and emergency management system.

  17. Proceedings of the 30th Southern Conservation Agricultural Systems Conference and the 8th Annual Georgia Conservation Production Systems Training Conference, Tifton, Georgia, July 29-31, 2008

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This 2008 conference to be held at the University of Georgia Tifton Campus Conference Center in Tifton, GA, on 29-31 July 2008, will be a joint effort of the 30th Southern Conservation Agricultural Systems Conference (SCASC) and the 8th Annual Conservation Production Systems Training Conference (CPS...

  18. Relating watershed nutrient loads to satellite derived estuarine water quality

    NASA Astrophysics Data System (ADS)

    Lehrter, J. C.; Le, C.

    2015-12-01

    Nutrient enhanced phytoplankton production is a cause of degraded estuarine water quality. Yet, relationships between watershed nutrient loads and the spatial and temporal scales of phytoplankton blooms and subsequent water quality impairments remain unquantified for most systems. This is partially due to a lack of observations. In many systems, satellite remote sensing of water quality variables may be used to supplement limited field observations and improve understanding of linkages to nutrients. Here, we present the results from a field and satellite ocean color study that quantitatively links nutrients to variations in estuarine water quality endpoints. The study was conducted in Pensacola Bay, Florida, an estuary in the northern Gulf of Mexico that is impacted by watershed nutrients. We developed new empirical band ratio algorithms to retrieve phytoplankton biomass as chlorophyll a (chla), colored dissolved organic matter (CDOM), and suspended particulate matter (SPM) from the MEdium Resolution Imaging Spectrometer (MERIS). MERIS had suitable spatial resolution (300-m) for the scale of Pensacola Bay (area = 370 km2, mean depth = 3.4 m) and a spectral band centered at wavelength 709 nm that was used to minimize the effect of organic matter on chla retrieval. The algorithms were applied to daily MERIS remote sensing reflectance (level 2) data acquired from 2003 to 2011 to calculate nine-year time-series of mean monthly chla, CDOM, and SPM concentrations. The MERIS derived time-series were then analyzed for statistical relations with time-series of mean monthly river discharge and river loads of nitrogen, phosphorus, dissolved organic carbon, and SPM. Regression analyses revealed significant relationships between river loads and MERIS water quality variables. The simple regression models provide quantitative predictions about how much chla, CDOM, and SPM concentrations in Pensacola Bay will increase with increased river loading, which is necessary information

  19. Identifying sources of acidity and spatial distribution of acid sulfate soils in the Anglesea River catchment, southern Australia

    NASA Astrophysics Data System (ADS)

    Wong, Vanessa; Yau, Chin; Kennedy, David

    2015-04-01

    Globally, coastal and estuarine floodplains are frequently underlain by sulfidic sediments. When exposed to oxygen, sulfidic sediments oxidise to form acid sulfate soils, adversely impacting on floodplain health and adjacent aquatic ecoystems. In eastern Australia, our understanding of the formation of these coastal and estuarine floodplains, and hence, spatial distribution of acid sulfate soils, is relatively well established. These soils have largely formed as a result of sedimentation of coastal river valleys approximately 6000 years BP when sea levels were one to two metres higher. However, our understanding of the evolution of estuarine systems and acid sulfate soil formation, and hence, distribution, in southern Australia remains limited. The Anglesea River, in southern Australia, is subjected to frequent episodes of poor water quality and low pH resulting in closure of the river and, in extreme cases, large fish kill events. This region is heavily reliant on tourism and host to a number of iconic features, including the Great Ocean Road and Twelve Apostles. Poor water quality has been linked to acid leakage from mining activities and Tertiary-aged coal seams, peat swamps and acid sulfate soils in the region. However, our understanding of the sources of acidity and distribution of acid sulfate soils in this region remains poor. In this study, four sites on the Anglesea River floodplain were sampled, representative of the main vegetation communities. Peat swamps and intertidal marshes were both significant sources of acidity on the floodplain in the lower catchment. However, acid neutralising capacity provided by carbonate sands suggests that there are additional sources of acidity higher in the catchment. This pilot study has highlighted the complexity in the links between the floodplain, upper catchment and waterways with further research required to understand these links for targeted acid management strategies.

  20. Contamination by Arsenate in Oxidizing Groundwater, Southern Gulf Coast Aquifer System, Texas

    NASA Astrophysics Data System (ADS)

    Gates, J. B.; Nicot, J.; Reedy, R. C.; Scanlon, B. R.

    2009-12-01

    Groundwater arsenic concentrations exceed the U.S. EPA maximum contaminant level for drinking water (10 μg/L) in about one-third of wells in the southern Gulf Coast Aquifer System (GCAS) in Texas, representing a potential public health hazard and an environmental compliance challenge to numerous small public water supply systems. The aim of this study is to better understand the hydrogeochemical mechanisms underpinning the widespread distribution of elevated groundwater arsenic concentrations in the region. Here we focus upon arsenic contamination in unconfined portions of the aquifer system. The investigation is based upon chemical analyses of a field transect of 27 groundwater samples collected from across three units of the GCAS; stratified water quality sampling from one additional well; and relevant water chemistry data from the Texas Water Development Board groundwater database (more than 500 samples). Chemical results from the field study showed that carbonate weathering and active recharge in the unconfined zone result in circum-neutral pH and oxidizing redox conditions, which are typically amenable to arsenic immobilization by adsorption of As(V) onto mineral oxides and clays. However, arsenic concentrations were found up to 129 μg/L (median 12 μg/L), and As(V) represented nearly 100% of total arsenic. Concentrations generally decreased with increasing distance from the Catahoula Formation (which contains abundant volcanic ash presumed to be the original arsenic source), through the overlying Jasper, Evangeline and Chicot Aquifers. Statistically significant pairwise correlations with arsenic were found for vanadium, silica and potassium, all of which were released during weathering of volcanic sediments and their degradation products. Silica that was co-released with arsenic may compete for sorption sites and reduce the capacity for arsenic adsorption. An important role for variable arsenic source availability was suggested by regional spatial

  1. Lakota Formation, southern Black Hills, South Dakota: an Early Cretaceous evolving fluvial system

    SciTech Connect

    Dahlstrom D.J.; Fox, J.E.

    1986-08-01

    The fluvial, Early Cretaceous Lakota Formation consists of four spatially and temporally distinct sandstone units in the southern Black Hills and southeastern Powder River basin. Three of these units crop out in proximity to an area of uranium roll-front development (Edgemont mining district) where approximately 2300 wells were drilled and logged. Comparison of the resistivity logs of several of these wells with continuous cores of the Lakota Formation confirms their lithologic sensitivity. These logs (utilized to assist in subsurface facies interpretations where cores were not available), cores, and outcrops are the basis for the following facies interpretations. The discharge, sediment load, and resulting sinuosity of this fluvial system varied substantially throughout the time of Lakota deposition. The oldest unit consists of tabular deposits with complex internal architecture comprised of cross-cutting lateral accretion deposits. Upward-fining grain size, upward-decreasing scale of sedimentary structures, and the angular relationship between lateral accretion surfaces and overlying crevasse-splay deposits support this conclusion. The intermediate unit of ephemeral stream sediments is characterized by abundant pebble- and cobble-strewn erosional surfaces with up to 1.5 m relief, very poor clast sorting, and trough and planar cross-bedding with concave-upward foresets. The youngest unit has a predominance of tabular cross-bedding with back flow climbing ripples and low dispersion of paleocurrent directions, suggesting a relatively straight, bed-load-type channel dominated by trains of sand waves.

  2. Hydrogeochemistry and statistical analysis applied to understand fluoride provenance in the Guarani Aquifer System, Southern Brazil.

    PubMed

    Marimon, Maria Paula C; Roisenberg, Ari; Suhogusoff, Alexandra V; Viero, Antonio Pedro

    2013-06-01

    High fluoride concentrations (up to 11 mg/L) have been reported in the groundwater of the Guarani Aquifer System (Santa Maria Formation) in the central region of the state of Rio Grande do Sul, Southern Brazil. In this area, dental fluorosis is an endemic disease. This paper presents the geochemical data and the combination of statistical analysis (Principal components and cluster analyses) and geochemical modeling to achieve the hydrogeochemistry of the groundwater and discusses the possible fluoride origin. The groundwater from the Santa Maria Formation is comprised of four different geochemical groups. The first group corresponds to a sodium chloride groundwater which evolves to sodium bicarbonate, the second one, both containing fluoride anomalies. The third group is represented by calcium bicarbonate groundwater, and in the fourth, magnesium is the distinctive parameter. The statistical and geochemical analyses supported by isotopic measurements indicated that groundwater may have originated from mixtures of deeper aquifers and the fluoride concentrations could be derived from rock/water interactions (e.g., desorption from clay minerals). PMID:23149723

  3. The oil and gas potential of southern Bolivia: Contributions from a dual source rock system

    SciTech Connect

    Hartshorn, K.G.

    1996-08-01

    The southern Sub-Andean and Chaco basins of Bolivia produce oil, gas and condensate from reservoirs ranging from Devonian to Tertiary in age. Geochemical evidence points to contributions from two Paleozoic source rocks: the Devonian Los Monos Formation and the Silurian Kirusillas Formation. Rock-Eval pyrolysis, biomarker data, microscopic kerogen analysis, and burial history modeling are used to assess the quality, distribution, and maturity of both source rock systems. The geochemical results are then integrated with the structural model for the area in order to determine the most likely pathways for migration of oil and gas in the thrust belt and its foreland. Geochemical analysis and modeling show that the primary source rock, shales of the Devonian Los Monos Formation, entered the oil window during the initial phase of thrusting in the sub-Andean belt. This provides ideal timing for oil accumulation in younger reservoirs of the thrust belt. The secondary source rock, although richer, consumed most of its oil generating capacity prior to the development of the thrust related structures. Depending on burial depth and location, however, the Silurian source still contributes gas, and some oil, to traps in the region.

  4. Geographical Information Systems and canine faecal contamination: the experience in the city of Naples (southern Italy).

    PubMed

    Veneziano, V; Rinaldi, L; Carbone, S; Biggeri, A; Cringoli, G

    2006-06-01

    Geographical Information Systems (GIS) can be used to make transect sampling when non-moving objects are to be counted, involving choosing a line or series of lines along which the counts are to take place. This approach has been used by us in order to study canine faecal contamination in the city of Naples (southern Italy), and to evaluate the consequent presence of canine parasitic elements. A GIS was constructed utilizing the geo-referenced digital photographs and the cadastral maps of Naples. In order to uniformly evaluate the canine faecal contamination throughout the city, a grid representing sub-areas of 1 km x 700 m was overlaid on the city map within the GIS. The territory of Naples was divided in 218 equal, rectangular sub-areas. In each sub-area a 1 km transect was drawn, and digitalized on-screen in the GIS. Canine faeces (copros in Greek) were counted along the transects in 143 sub-areas. In these sub-areas, 415 copros were collected and examined. Out of the 143 sub-areas, 141 contained canine copros. The results of the negative binomial regression model showed a positive association between the number of copros and the human population density. Out of the total of 415 copros, 70 (16.9%) were positive for parasitic elements; eggs of Toxocara canis, Toxascaris leonina, Ancylostoma caninum and Trichuris vulpis were found, as well as oocysts of Isospora canis. PMID:16881413

  5. SICS: the Southern Inland and Coastal System interdisciplinary project of the USGS South Florida Ecosystem Program

    USGS Publications Warehouse

    U.S. Geological Survey

    2011-01-01

    State and Federal agencies are working jointly on structural modifications and improved water-delivery strategies to reestablish more natural surface-water flows through the Everglades wetlands and into Florida Bay. Changes in the magnitude, duration, timing, and distribution of inflows from the headwaters of the Taylor Slough and canal C-111 drainage basins have shifted the seasonal distribution and extent of wetland inundation, and also contributed to the development of hypersaline conditions in nearshore embayments of Florida Bay. Such changes are altering biological and vegetative communities in the wetlands and creating stresses on aquatic habitat. Affected biotic resources include federally listed species such as the Cape Sable seaside sparrow, American crocodile, wood stork, and roseate spoonbill. The U.S. Geological Survey (USGS) is synthesizing scientific findings from hydrologic process studies, collecting data to characterize the ecosystem properties and functions, and integrating the results of these efforts into a research tool and management model for this Southern Inland and Coastal System(SICS). Scientists from all four disciplinary divisions of the USGS, Biological Resources, Geology, National Mapping, and Water Resources are contributing to this interdisciplinary project.

  6. Response of the Southern Benguela upwelling system to fine-scale modifications of the coastal wind

    NASA Astrophysics Data System (ADS)

    Desbiolles, F.; Blanke, B.; Bentamy, A.; Roy, C.

    2016-04-01

    We analyze the results of a regional model of the Southern Benguela upwelling system forced by wind stress fields derived from QuikSCAT observations. Two different horizontal resolutions are considered for the wind stress: QS25 and QS50, corresponding to native 25 and 50 km grids, respectively. The differences between both products highlight the primary importance of fine-scale momentum fluxes for both the structure and intensity of the wind- and wind-curl-driven upwelling. Using QS25, we show that the coastal Ekman transport is reduced, leading to a warmer SST and a reduced oceanic coastal jet. QS25 finer wind stress curl patterns also favor the development of a stronger and shallower poleward undercurrent. The addition of a coastal wind correction to QS25 lets us investigate the possible implications of an imbalance between Ekman transport and Ekman pumping: a wind reduction in the coastal band often reduces the SST cooling, but the two mechanisms compensate each other when the characteristic length scales of the coastal upwelling and the orography-induced wind drop-off are similar.

  7. Evidence of a large seasonal coastal upwelling system along the southern shelf of Australia

    NASA Astrophysics Data System (ADS)

    Kämpf, Jochen; Doubell, Mark; Griffin, David; Matthews, Roger L.; Ward, Tim M.

    2004-05-01

    We report observational existence of a large seasonal coastal upwelling system that establishes in austral summer (December-April) along Australian southern shelves. Wind-driven upwelling events occur simultaneously in three upwelling centres spanning a distance of ~800 km. During each summer period there are ~2-3 major upwelling events, each lasting ~1 week. The simultaneous, rapid response of SST to wind forcing in the upwelling centres, which display vastly different shelf widths, points to the existence of a larger-scale process that carries cold water onto the shelf prior to the upwelling season. Exploration of a major upwelling event in March 1998 shows the evolution of peak surface chlorophyll-a concentrations of >4 μg/L lagging the onset of upwelling by ~1 week. The associated (exponential) growth rate can be estimated at 0.4 d-1. Another week later we found a distinct sub-surface chlorophyll-a maximum at a depth of 50 m centred along the upwelling front. Reasons for the formation of this maximum are not fully understood.

  8. Structure of the Subduction System in Southern Peru from Seismic Array Data

    NASA Astrophysics Data System (ADS)

    Phillips-Alonge, Kristin

    Southern Peru represents a subduction transition region from normal subduction in the southernmost part of Peru to flat slab subduction in central Peru. In order to learn more about the structure of southern Peru, causes of flat slab subduction, and the nature of the transition from normal to flat slab subduction, we installed three seismic arrays utilizing a total of about 100 broadband stations. The first installed array samples the normal subduction region, while the second samples the transition from normal to flat subduction, and the third samples the flat slab region near where the Nazca Ridge is presently subducting. Data from teleseismic events greater than 30 degrees distance from Peru was analyzed using the receiver function method that makes use of P to S converted phases at interfaces such as the Moho to provide information about the structure directly beneath each station. A strong signal from the Moho was observed for each array and was found to have a maximum depth of around 75 km beneath the Altiplano. The average crustal Vp/Vs ratio was also estimated and was found to have an average value of around 1.75 beneath the Altiplano. The shape of the slab was also clarified for the three arrays. The transition from normal to flat slab subduction appears to be a contortion rather than a break in the slab. In addition to those signals, a positive impedance midcrustal signal at about 40 km depth was widely observed for stations on the eastern side of the arrays. The midcrustal signal is indicative of a velocity increase in the lower crust and is suggested to be an observation of the underthrusting Brazilian shield which would have implications for the timing of uplift in the Andes. Finite difference modeling with velocity models that include a midcrustal structure produces synthetics which are consistent with receiver function observations. Receiver function results and other related methods provide a simple way of making direct observations of key

  9. Sheep production and marketing system in southern Ethiopia: the case of Awassazuria district.

    PubMed

    Tadesse, Estefanos; Negesse, Tegene; Abebe, Girma

    2015-10-01

    A survey was conducted in Awassazuria district of southern Ethiopia to characterize sheep production system. A structured questionnaire was used to collect data. Using purposive sampling, a total of 120 households from the district were included in the survey. Collected data were analyzed using descriptive statistics. Result indicated that Kajima neighbourhood has more (p<0.05) grazing land than the others. Communal grazing, roadside grazing, enset (false banana, Ensete ventricosum), banana leaf and private grazing land were major feed resources for sheep. Lake Awassa and tap water were permanent water sources. Watering frequency of sheep varies from once a day to once in 4 days. Sheep are primarily kept to generate income and equilibrate benefit and risk and for home consumption. The criteria used by the households for purchase and sale of sheep are physical characteristics (coat colour, horn and tail) (46.7 %), body conformation (35 %), age (10.8 %) and known local ecotype (7.5 %). The reasons of slaughter of sheep include festival (55 %), childbirth (18.3 %), wedding (12.5 %), mutton for home (9 %), circumcision (5 %) and for guest (1.7 %). Farmers fatten sheep for New Year (60 %), Easter (30.8 %), Christmas and Arefa (Eid al-Adha celebration (Feast of the Sacrifice); <10 %). The reasons for expansion of sheep flock in the future were market price, high market demand, immediate return, ease of management, equilibrium between benefits and risks and suitability for home consumption, ranked in decreasing order of importance. The sheep production in southern Ethiopia is constrained by shortage of grazing land (23.3 %), recurrent drought (17.5 %), disease and parasite (15 %), marketing (10.8 %), water shortage (9 %) and other constraints including predators and lack of input, capital and lack of extension service. The presence of diversified and environmentally adaptable sheep breeds, high demand of mutton in the Awassa town and presence of nutritious and unutilized

  10. A mega-splay fault system and tsunami hazard in the southern Ryukyu subduction zone

    NASA Astrophysics Data System (ADS)

    Hsu, Shu-Kun; Yeh, Yi-Ching; Sibuet, Jean-Claude; Doo, Wen-Bin; Tsai, Ching-Hui

    2013-01-01

    In April 1771, a subduction earthquake generated a great tsunami that struck the south Ryukyu islands and killed ˜12,000 people, whereas its mechanism is still enigmatic (Nakata and Kawana, 1995; Nakamura, 2006; Matsumoto et al., 2009). In this paper, we show its probable source on a mega-splay fault system existing along the southern Ryukyu forearc. Analyses of deep multi-channel seismic reflection profiles indicate that the mega-splay fault system is rising from the summit of a ˜1 km high ridge situated at a ˜5° landward dipping plate interface. An outer ridge marks the seafloor outcrop of the splay fault system and separates the landward inner wedge and the oceanward outer wedge. The inner wedge is uplifting and exhibits widespread normal faulting while the outer wedge shows folded structures. The mega-splay fault system is parallel to the Ryukyu Trench east of 125.5°E and is estimated to be ˜450 km long. The origin of this south Ryukyu mega-splay fault system is ascribed to a resistant subduction of the elevated transverse ridges associated with the subducting portion of the trench-parallel Luzon-Okinawa Fracture Zone. In contrast, no similar splay fault is found west of 125.5°E where the oblique subduction has produced large shear zones along the south Ryukyu forearc. We infer that a thrust earthquake linked to the mega-splay fault system is responsible for the south Ryukyu tsunami. However, another possible scenario of generating a large tsunami affecting the south Ryukyu islands is that the subducted ridge in the western end of the mega-splay fault system nucleated a large earthquake and simultaneously triggered the ˜100 km long E-W trending strike-slip fault west of 125.5°E and induced a southward-dipping tsunami-genic subsidence. In any case, after a quiescence of ˜241 yr, a large earthquake and tsunami is anticipated in the south Ryukyu forearc in the near future.

  11. Impact of estuarine pollution on birds

    USGS Publications Warehouse

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

    1977-01-01

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

  12. Estimating flood exceedance probabilities in estuarine regions

    NASA Astrophysics Data System (ADS)

    Westra, Seth; Leonard, Michael

    2016-04-01

    Flood events in estuarine regions can arise from the interaction of extreme rainfall and storm surge. Determining flood level exceedance probabilities in these regions is complicated by the dependence of these processes for extreme events. A comprehensive study of tide and rainfall gauges along the Australian coastline was conducted to determine the dependence of these extremes using a bivariate logistic threshold-excess model. The dependence strength is shown to vary as a function of distance over many hundreds of kilometres indicating that the dependence arises due to synoptic scale meteorological forcings. It is also shown to vary as a function of storm burst duration, time lag between the extreme rainfall and the storm surge event. The dependence estimates are then used with a bivariate design variable method to determine flood risk in estuarine regions for a number of case studies. Aspects of the method demonstrated in the case studies include, the resolution and range of the hydraulic response table, fitting of probability distributions, computational efficiency, uncertainty, potential variation in marginal distributions due to climate change, and application to two dimensional output from hydraulic models. Case studies are located on the Swan River (Western Australia), Nambucca River and Hawkesbury Nepean River (New South Wales).

  13. Interpretation of the Hydrothermal System in Kirishima Hot Spring Village, Southern Kyushu, Japan

    NASA Astrophysics Data System (ADS)

    Yonekura, Yusaku; Fujimitsu, Yasuhiro; Nishijima, Jun

    2014-05-01

    It is very important to understand hydrothermal systems for sustainable utilizing of hot springs. However, in Japan, most of the large hot springs are located in national parks. Therefore, explorations such as geochemical, geophysical or boring surveys to interpret the hydrothermal systems had not been conducted enough. For this reason, hydrothermal systems of some hot springs in Japan have not been made clear even now. We constructed a conceptual model to interpret the hydrothermal system of Kirishima Hot Spring Village in Kirishima national park, southern part of Kyushu, Japan. There are many hot springs in Kirishima Hot Spring Village, such as Maruo, Hayashida, and Myoban hot spring areas. Kirishima Hot Spring Village is located in southwestern part of Kirishima volcanoes, like Onami-ike volcano, and the altitude of Maruo area is about 600 m and that of Hayashida and Myoban areas is about 800 m. In order to interpret the hydrothermal system in Kirishima Hot Spring Village, we need to understand three important factors which are heat source, hot spring water, and subsurface structure. In January 2011, Shinmoe-dake volcano of Kirishima volcanoes made a large scale eruption. Then, the pressure source of Kirishima volcanoes is expected to be located in about 2 km west of Onami-ike volcano and its estimated altitude is about -7 km (Kobayashi et al., 2011). We used this pressure source for our conceptual model as a heat source. Secondary, we tried to clarify the fluid of Kirishima Hot Spring Village by considering the chemical compositions of hot spring water. In addition, we made a Na-K-Mg diagram to estimate the reservoir temperature and find that spring water has reached equilibrium or not. As a result, we supposed that hot spring water of Maruo area is magmatic, and that of Hayashida and Myoban area is consisted of sulfate and meteoric water. Thirdly, we used gravity data, which is the result from previous study and our field survey, to make a residual Bouguer

  14. Numerical modeling of groundwater flow in the coastal aquifer system of Taranto (southern Italy)

    NASA Astrophysics Data System (ADS)

    De Filippis, Giovanna; Giudici, Mauro; Negri, Sergio; Margiotta, Stefano; Cattaneo, Laura; Vassena, Chiara

    2014-05-01

    The Mediterranean region is characterized by a strong development of coastal areas with a high concentration of water-demanding human activities, resulting in weakly controlled withdrawals of groundwater which accentuate the saltwater intrusion phenomenon. The worsening of groundwater quality is a huge problem especially for those regions, like Salento (southern Italy), where a karst aquifer system represents the most important water resource because of the deficiency of a well developed superficial water supply. In this frame, the first 2D numerical model describing the groundwater flow in the karst aquifer of Salento peninsula was developed by Giudici et al. [1] at the regional scale and then improved by De Filippis et al. [2]. In particular, the estimate of the saturated thickness of the deep aquifer highlighted that the Taranto area is particularly sensitive to the phenomenon of seawater intrusion, both for the specific hydrostratigraphic configuration and for the presence of highly water-demanding industrial activities. These remarks motivate a research project which is part of the research program RITMARE (The Italian Research for the Sea), within which a subprogram is specifically dedicated to the problem of the protection and preservation of groundwater quality in Italian coastal aquifers and in particular, among the others, in the Taranto area. In this context, the CINFAI operative unit aims at providing a contribution to the characterization of groundwater in the study area. The specific objectives are: a. the reconstruction of the groundwater dynamic (i.e., the preliminary identification of a conceptual model for the aquifer system and the subsequent modeling of groundwater flow in a multilayered system which is very complex from the hydrostratigraphical point of view); b. the characterization of groundwater outflows through submarine and subaerial springs and the water exchanges with the shallow coastal water bodies (e.g. Mar Piccolo) and the off

  15. Role of native and exotic woody vegetation in soil restoration in active gully systems (southern Ecuador)

    NASA Astrophysics Data System (ADS)

    Borja Ramon, Pablo; Alvarado Moncayo, Dario; Vanacker, Veerle; Cisneros, Pedro; Molina, Armando; Govers, Gerard

    2015-04-01

    Revegetation projects in degraded lands have the potential to recover essential soil functions. If vegetation restoration is combined with bioengineering techniques, such as the construction of retention dams in active gully systems, soil restoration could be enhanced. One important aspect of this process is the role of vegetation on restoration of soil chemical and physical properties. There is currently a lack of knowledge on the potential of soil restoration in active badland systems, as most studies have concentrated on the direct and visible effect of revegetation on erosion control. The aim of this study is to evaluate the role of revegetation and bioengineering works on the restoration of soil physical and chemical properties. The analyses are realized in a highly degraded area of 3 km2, located in the lower part of the Loreto catchment (Southern Ecuadorian Andes). First, the soil physical and/or chemical parameters that are most sensitive to track environmental change were evaluated. Second, the role of vegetation on soil restoration was quantified. . Soil samples were taken in sites with different vegetation cover, land use and physiographic position. The following physical and chemical parameters were measured: volumetric water content (θsat, θact), bulk density, pH, texture, organic matter, C and N content. Our first results do not show a clear relationship between volumetric water content at saturation (θsat), bulk density, or C content. The saturation water content does not vary significantly between different sites, or land use types. However, significant differences are found between sites at different stages of restoration; and this for most chemical and physical soil properties. Vegetation cover (%) appears to exert a strong control on the C content in the mineral soils. The highest C values are found in soils of forest plantations with Eucalyptus and Pinus species. These plantations are located in areas that were previously affected by active

  16. Geochemical and isotopic investigation of the aquifer system in the Djerid-Nefzaoua basin, southern Tunisia

    NASA Astrophysics Data System (ADS)

    Kamel, Samir; Dassi, Lassaad; Zouari, Kamel; Abidi, Brahim

    2005-11-01

    In the Djerid-Nefzaoua region, southern Tunisia, about 80% of agricultural and domestic water supply is provided by the complex terminal (CT) aquifer. However, 20% of this demand is provided by other hydraulically connected aquifers, namely the continental intercalaire (CI) and the Plio-Quaternary (PQ). Overexploitation of the CT aquifer for agricultural practices has contributed to the loss of the artesian condition and the decline of groundwater level which largely increased the downward leakage from the shallow PQ aquifer. Excess irrigation water concentrates at different rates in the irrigation channels and in the PQ aquifer itself. Then, it returns to the CT aquifer and mixes with water from the regional flow system, which contributes to the salinization of the CT groundwater. A geochemical and isotopic study had been undertaken over a 2-years period in order to investigate the origin of waters pumped from the CT aquifer with an emphasis on its hydraulic relationships with the underlying and the overlying CI and PQ aquifers. Geochemistry indicates that groundwater samples collected from different wells show an evolution of the water types from Na-Cl to Ca-SO4-Cl. Dissolution of halite, gypsum and anhydrite-bearing rocks is the main mechanism that leads to the salinization of the groundwater. Isotopic data indicate the old origin of all groundwater in the aquifer system. Mixing and evaporation effects characterizing the CT and the PQ aquifers were identified using δ2H and δ18O relationship and confirmed by the conjunction of δ2H with chloride concentration.

  17. Turkish Straits System and Southern Black Sea: Exchange. Mixing and Shelf / Canyon Interactions

    NASA Astrophysics Data System (ADS)

    Özsoy, Emin; Gürses, Özgür; Tutsak, Ersin

    2015-04-01

    Based largely on an experiment employing high-resolution measurements carried out in June-July 2013 and re-interpretation of past experiments, the oceanographic variability of the exchange through the Turkish Straits System (TSS) and the interactions with the southern Black Sea are revealed through CTD, ADCP, oxygen and light transmission measurements. The exchange flow is primarily governed by the complex topography spanning two narrow straits, wide continental shelf regions, steep slopes and numerous canyons connecting deep basins. Water properties and currents in the high energy environment depends on the mosaic of fine-scale processes and pathways. The TSS, often approximated as a two-layer system has a hydraulically controlled, upper ocean and straits intensified regime, leading to surface jets and bottom plumes participating in mixing and renewal processes. The exit of the 'Mediterranean effluent' onto the Black Sea past a sill overflow from the Bosphorus passes through two subsequent hydraulic jumps and proceeds along a narrow canyon that veers to the west clear of the greater Bosphorus Canyon finally cascading down the few small canyons. A diffusive spread from the bottom vein of salty water reforms to the east and spills down the Bosphorus Canyon. The suspended particulate signature of the cascade, as well as its influence in hydrography is traced over the shelf and slope waters and through the numerous canyons into deep water where the reformed flow is found to sustain signatures of the past evolution of intrusive waters. An evaluation of the processes is given with reference to model development carried out in parallel to the analyses of the measurements.

  18. Growth and production of the copepod community in the southern area of the Humboldt Current System

    NASA Astrophysics Data System (ADS)

    Escribano, R.; Bustos-Ríos, E.; Hidalgo, P.; Morales, C. E.

    2015-02-01

    Zooplankton production is a critical issue for understanding marine ecosystem structure and dynamics, however, its time-space variations are mostly unknown in most systems. In this study, estimates of copepod growth and production (CP) in the coastal upwelling and coastal transition zones off central-southern Chile (∼35-37° S) were obtained from annual cycles during a 3 year time series (2004, 2005, and 2006) at a fixed shelf station and from spring-summer surveys during the same years. C-specific growth rates (g) varied extensively among species and under variable environmental conditions; however, g values were not correlated to either near surface temperature or copepod size. Copepod biomass (CB) and CP were higher within the coastal upwelling zone (<50 km) and both decreased substantially from 2004 to 2006. Annual CP ranged between 24 and 52 g C m-2 year-1 with a~mean annual P/B ratio of 2.7. We estimated that CP could consume up to 60% of the annual primary production (PP) in the upwelling zone but most of the time is around 8%. Interannual changes in CB and CP values were associated with changes in the copepod community structure, the dominance of large-sized forms replaced by small-sized species from 2004 to 2006. This change was accompanied by more persistent and time extended upwelling during the same seasonal period. Extended upwelling may have caused large losses of CB from the upwelling zone due to an increase in offshore advection of coastal plankton. On a larger scale, these results suggest that climate-related impacts of increasing wind-driven upwelling in coastal upwelling systems may generate a negative trend in zooplankton biomass.

  19. Beroe gracilis (Ctenophora) from the Humboldt Current System: first occurrence of this species in the southern hemisphere.

    PubMed

    Oliveira, Otto M P; Feliú, Guillermo; Palma, Sergio

    2014-01-01

    Beroe gracilis Künne, 1939 is a small neritic ctenophore, previously recorded only from cold waters of the northern hemisphere. The present study provides the first record of the species in the southern hemisphere, found in the surface layer of the Humboldt Current System off the central Chilean coast (32°-36.5° S). A complete description of this material is provided. PMID:25081170

  20. Trophic functioning of the St. Lucia estuarine lake during a drought phase assessed using stable isotopes

    NASA Astrophysics Data System (ADS)

    Govender, Natasha; Smit, Albertus J.; Perissinotto, Renzo

    2011-06-01

    The St. Lucia Estuary is Africa's largest estuarine system and is currently experiencing the stress of prolonged freshwater deprivation, manifested by extremely low water levels and hypersalinity. These unprecedented conditions have raised questions regarding the trophic functioning of the ecosystem. Despite the substantial amount of research previously undertaken within this system, no studies of food web structure and function have yet been documented. This study therefore aimed to examine the food web structure of the St. Lucia estuary system through the use of carbon and nitrogen stable isotope analysis. Analysis of carbon isotope ratios indicates that benthic carbon sources are most utilised at sites with low water levels and generally higher salinity (Catalina Bay, Charter's Creek). Conversely, the estuarine region of the mouth and Narrows, with its elevated water levels and lower salinity, still sustains a viable pelagic food web. Analysis of δ15N ratios indicates that the number of trophic transfers (food chain length) might be related to water levels. Overall, the study provides a greater understanding of the ecological processes of this complex estuarine lake, which may allow for future comparisons of trophic functioning under drought and normal/wet conditions to be made.

  1. Data and Visualizations in the Southern California Earthquake Center's Fault Information System

    NASA Astrophysics Data System (ADS)

    Perry, S.

    2003-12-01

    The Southern California Earthquake Center's Fault Information System (FIS) provides a single point of access to fault-related data and models from multiple databases and datasets. The FIS is built of computer code, metadata and Web interfaces based on Web services technology, which enables queries and data interchange irrespective of computer software or platform. Currently we have working prototypes of programmatic and browser-based access. The first generation FIS may be searched and downloaded live, by automated processes, as well as interactively, by humans using a browser. Users get ascii data in plain text or encoded in XML. Via the Earthquake Information Technology (EIT) Interns (Juve and others, this meeting), we are also testing the effectiveness of querying multiple databases using a fault database ontology. For more than a decade, the California Geological Survey (CGS), SCEC, and the U. S. Geological Survey (USGS) have put considerable, shared resources into compiling and assessing published fault data, then providing the data on the Web. Several databases now exist, with different formats, datasets, purposes, and users, in various stages of completion. When fault databases were first envisioned, the full power of today's internet was not yet recognized, and the databases became the Web equivalents of review papers, where one could read an overview summation of a fault, then copy and paste pertinent data. Today, numerous researchers also require rapid queries and downloads of data. Consequently, the first components of the FIS are MySQL databases that deliver numeric values from earlier, text-based databases. Another essential service provided by the FIS is visualizations of fault representations such as those in SCEC's Community Fault Model. The long term goal is to provide a standardized, open-source, platform-independent visualization technique. Currently, the FIS makes available fault model viewing software for users with access to Matlab or Java3D

  2. Covariability of zooplankton gradients with glider-detected density fronts in the Southern California Current System

    NASA Astrophysics Data System (ADS)

    Powell, Jesse R.; Ohman, Mark D.

    2015-02-01

    Fronts represent sharp boundaries between water masses, but seasonal and interannual variation in their occurrence and effects on the distributions of pelagic organisms are poorly understood. This study reports results from six years of ocean front observations (2006-2011) along two transect lines across the Southern California Current System (SCCS) using autonomous Spray ocean gliders. During this time, 154 positive near-surface density fronts were identified within 124 completed transects consisting of nearly 23,000 vertical profiles. The incidence of surface density fronts showed distinct seasonality along line 80 off Pt. Conception, with fewer fronts occurring during winter months and more numerous fronts in the nearshore and during spring, summer and fall. On line 90, fronts were the least common nearshore and most frequent in a transitional region offshore. Horizontal density gradients in the surface layer (0-50 m) were significantly correlated with horizontal gradients in surface layer Chlorophyll-a (Chl-a) fluorescence, as well as with mean volume backscatter (MVBS) recorded by a 750 kHz acoustic Doppler profiler. Density fronts were not only zones of rapidly changing phytoplankton and zooplankton biomass concentrations, but also more likely to be zones of enhanced acoustic backscatter and Chl-a fluorescence than regions flanking the fronts. MVBS and Chl-a gradients were significantly correlated with gradients in other hydrographic variables such as temperature, salinity, and spiciness, and weakly with cross-track current velocity, though density gradients remained the single best predictor of strong MVBS and fluorescence gradients. Large mobile predators foraging in the vicinity of such features could locate habitat with higher zooplankton biomass concentrations up to 85% of the time by traveling up local density gradients (i.e., toward rather than away from denser surface waters). We discuss implications of these results in the context of long-term trends

  3. Geomorphic features off southern California as seen by GLORIA side-scan sonar system

    SciTech Connect

    Edwards, B.D.; Field, M.E.; Carlson, P.R.; Kenyon, N.H.

    1985-02-01

    Approximately 165,000 km/sup 2/ of the sea floor off southern California was mapped during May 1984, as part of a USGS/IOS cooperative program to study the newly proclaimed Exclusive Economic Zone (EEZ) of the US Pacific margin. The area was insonified using the Geological Long-Range Inclined Asdic (GLORIA), a long-range side-scan sonar system. Images were corrected for water-column velocity anomalies, for along-track distortions caused by acoustic ray travel paths. A photomosaic of the overlapping sonographs has been compiled at a scale of 1:375,000. The basins of the inner California continental borderland are characterized by both sinuous channel and fan complexes and by feathery acoustic patterns indicating active sediment transport. In contrast, outer borderland basins appear to be more sediment starved, exhibit large areas of sediment failure, and show significant structural influence. West of Patton Escarpment, the sonographs are dominated by acoustic patterns showing volcanic ridges and seamounts and by deposits of the Monterey and Arguello fans. Arguello fan, for example, exhibits multiple sinuous channels that have transported sediment 60 km south from the canyon mouth. These channels coalesce into a single 100-km long, westward-meandering channel that terminates in a 600-m deep box canyon. A zone of sediment failure is identifiable on the north levee of an upper fan channel. Tectonic trends associated with oceanic basement are highlighted by the terminus of the west-trending Murray Fracture Zone and by the prevailing northeast trend of volcanic ridge and seamount chains.

  4. Variation in ultrafiltered and LMW organic matter fluorescence properties under simulated estuarine mixing transects: 1. Mixing alone

    NASA Astrophysics Data System (ADS)

    Boyd, Thomas J.; Barham, Bethany P.; Hall, Gregory J.; Osburn, Christopher L.

    2010-09-01

    Ultrafiltered and low molecular weight dissolved organic matter (UDOM and LMW-DOM, respectively) fluorescence was studied under simulated estuarine mixing using samples collected from Delaware, Chesapeake, and San Francisco Bays (USA) transects. UDOM was concentrated by tangential flow ultrafiltration (TFF) from the marine (>33 PSU), mid-estuarine (˜16 PSU), and freshwater (<1 PSU) members. TFF permeates (<1 kDa) from the three members were used to create artificial salinity transects ranging from ˜0 to ˜36, with 4 PSU increments. UDOM from the end- or mid-members was added in equal amounts to each salinity-mix. Three-dimensional fluorescence excitation-emission matrix (EEMs) spectra were generated for each end-member permeate and UDOM through the full estuarine mixing transect. Fluorescence components such as proteinaceous, terrigenous, and marine derived humic peaks, and certain fluorescent ratios were noticeably altered by simulated estuarine mixing, suggesting that LMW DOM and UDOM undergo physicochemical alteration as they move to or from the freshwater, mid-estuarine, or coastal ocean members. LMW fluorescence components fit a decreasing linear mixing model from mid salinities to the ocean end-member, but were more highly fluorescent than mixing alone would predict in lower salinities (<8). Significant shifts were also seen in UDOM peak emission wavelengths with blue-shifting toward the ocean end-member. Humic-type components in UDOM generally showed lower fluorescent intensities at low salinities, higher at mid-salinities, and lower again toward the ocean end-member. T (believed to be proteinaceous) and N (labile organic matter) peaks behaved similarly to each other, but not to B peak fluorescence, which showed virtually no variation in permeate or UDOM mixes with salinity. PCA and PARAFAC models showed similar results suggesting trends could be modeled for DOM end- and mid-member sources. Changes in fluorescence properties due to estuarine mixing may be

  5. Middle Jurassic incised valley fill (eolian/estuarine) and nearshore marine petroleum reservoirs, Powder River basin

    SciTech Connect

    Ahlbrandt, T.S.; Fox, J.E.

    1997-07-01

    Paleovalleys incised into the Triassic Spearfish Formation (Chugwater equivalent) are filled with a vertical sequence of eolian, estuarine, and marine sandstones of the Middle Jurassic (Bathonian age) Canyon Springs Sandstone Member of the Sundance Formation. An outcrop exemplifying this is located at Red Canyon in the southern Black Hills, Fall River County, South Dakota. These paleovalleys locally have more than 300 ft of relief and are as much as several miles wide. Because they slope in a westerly direction, and Jurassic seas transgressed into the area from the west there was greater marine-influence and more stratigraphic complexity in the subsurface, to the west, as compared to the Black Hills outcrops. In the subsurface two distinctive reservoir sandstone beds within the Canyon Springs Sandstone Member fill the paleovalleys. These are the eolian lower Canyon Springs unit (LCS) and the estuarine upper Canyon Springs unit (UCS), separated by the marine {open_quotes}Limestone Marker{close_quotes} and estuarine {open_quotes}Brown Shale{close_quotes}. The LCS and UCS contain significant proven hydrocarbon reservoirs in Wyoming (about 500 MMBO in-place in 9 fields, 188 MMBO produced through 1993) and are prospective in western South Dakota, western Nebraska and northern Colorado. Also prospective is the Callovian-age Hulett Sandstone Member which consists of multiple prograding shoreface to foreshore parasequences, as interpreted from the Red Canyon locality. Petrographic, outcrop and subsurface studies demonstrate the viability of both the Canyon Springs Sandstone and Hulett Sandstone members as superior hydrocarbon reservoirs in both stratigraphic and structural traps. Examples of fields with hydrocarbon production from the Canyon Springs in paleovalleys include Lance Creek field (56 MMBO produced) and the more recently discovered Red Bird field (300 MBO produced), both in Niobrara County, Wyoming.

  6. Biotic resistance to invasion along an estuarine gradient

    PubMed Central

    Hovel, Kevin A.

    2010-01-01

    Biotic resistance is the ability of native communities to repel the establishment of invasive species. Predation by native species may confer biotic resistance to communities, but the environmental context under which this form of biotic resistance occurs is not well understood. We evaluated several factors that influence the distribution of invasive Asian mussels (Musculista senhousia) in Mission Bay, a southern California estuary containing an extensive eelgrass (Zostera marina) habitat. Asian mussels exhibit a distinct spatial pattern of invasion, with extremely high densities towards the back of Mission Bay (up to 4,000 m−2) in contrast with near-complete absence at sites towards the front of the bay. We established that recruits arrived at sites where adult mussels were absent and found that dense eelgrass does not appear to preclude Asian mussel growth and survival. Mussel survival and growth were high in predator-exclusion plots throughout the bay, but mussel survival was low in the front of the bay when plots were open to predators. Additional experiments revealed that consumption by spiny lobsters (Panulirus interruptus) and a gastropod (Pteropurpura festiva) likely are the primary factors responsible for resistance to Asian mussel invasion. However, biotic resistance was dependent on location within the estuary (for both species) and also on the availability of a hard substratum (for P. festiva). Our findings indicate that biotic resistance in the form of predation may be conferred by higher order predators, but that the strength of resistance may strongly vary across estuarine gradients and depend on the nature of the locally available habitat. Electronic supplementary material The online version of this article (doi:10.1007/s00442-010-1700-7) contains supplementary material, which is available to authorized users. PMID:20602118

  7. Pronounced changes in carbonate system and temperature history of the Southern California margin from LGM to present

    NASA Astrophysics Data System (ADS)

    Quintana Krupinski, N. B.; Pak, D. K.; Hill, T. M.; Paytan, A.

    2012-12-01

    Millennial-scale records of the marine carbonate system and its natural variability provide long-term perspective on anthropogenically-induced ocean acidification, and provide a basis for determining whether there is a critical threshold at which organisms may be negatively affected by changing carbonate saturation and pH. The state, stability and natural variability of pre-anthropogenic marine carbonate systems can be reconstructed from carbonate system proxies in foraminiferal calcite. Using newly calibrated proxies, we quantify the long-term history and variability of the surface water carbonate system in the Southern California Borderland, a coastal region that experiences substantial pH fluctuations today. Our reconstruction of temperature also allows comparison with other nearby Southern California temperature reconstructions. We present trace metal (B/Ca, U/Ca and Mg/Ca), stable isotope (δ18O , δ13C ) and shell weight results from the planktonic foraminifera G. bulloides and N. incompta (N. pachyderma (d)) from Santa Monica Basin (SMB; ODP 1015) to reconstruct the past surface ocean carbonate system and temperature for the past ~32ka. We observe a gradual decrease in B/Ca in the thermocline-dwelling N. incompta from 20ka to ~12ka, likely reflecting the decrease in global ocean pH and [CO32-] during deglaciation. Changes in temperature and ocean carbonate chemistry can be observed during the Younger Dryas and Bolling-Allerod in trace metal, stable isotope and shell weight records. Compared with other nearby Southern California ODP sites, temperatures from Mg/Ca during deglaciation in SMB are cooler by ~1-3 degrees, and show a larger temperature difference between G. bulloides and N. incompta during glacial time than other regional sites. These results strengthen evidence that the southern California Borderland shows a strong atmospheric teleconnection to North Atlantic climate changes, and also provide the opportunity to assess what aspects of southern

  8. Bioconcentration of endosulfan in different body tissues of estuarine organisms under sublethal exposure

    SciTech Connect

    Rajendran, N. ); Venugopalan, V.K. )

    1991-01-01

    The organochlorine pesticide endosulfan is applied in the agricultural fields as liquid in India. Investigations have revealed the occurrence and distribution of endosulfan in both biotic and abiotic components of Vellar estuary. The results from static bioassay studies revealed that fishes were more susceptible to the organochlorine pesticides than mollusks. Though the available information on the uptake of endosulfan by the estuarine organisms are limited to whole body tissues, no attempt has been made to find out the extent of uptake of pesticides by the different body tissues of the estuarine organisms. Hence the present study was planned to determine the bioconcentration of endosulfan in different tissues of fishes Mugil cephalus, Mystus gulio, oyster Crassostrea madrasensis and clam Katelysia opima based on the measured concentration of endosulfan in the experimental medium of the continuous flow through system for a period of 10 d.

  9. Comparative evaluation of effects of ozonated and chlorinated thermal discharges on estuarine and freshwater organisms

    SciTech Connect

    Guerra, C.R.; Sugam, R.; Meldrim, J.W.; Holmstrom, E.R.; Balog, G.E.

    1980-08-01

    As a part of a program at PSE and G designed to examine the feasibility of ozonation as an alternative to chlorination for control of biofouling in once-through cooling systems, the biological effects of ozonated and chlorinated thermal discharges were evaluated with estuarine and freshwater organisms. Mortality at salinities between 0.5 to 2.5 ppt with mummichog and white perch indicated greater toxicity for chlorine while the alewife, spottail shiner, rainbow trout and white perch in freshwater were more sensitive to ozone. Behavioral and physograhic results were consistent with those observed in toxicity studies. Initial cough response and avoidance concentrations of mummicog and white perch in estuarine waters were lower when exposed to chlorine than to ozone. In freshwater, blueback herring, alewife, rainbow trout, spottail shiner, banded killifish, and white perch avoided lower concentrations of ozone than chlorine.

  10. Sediment measurement in estuarine and coastal areas

    NASA Technical Reports Server (NTRS)

    Shelley, P. E.

    1976-01-01

    A survey of uses of estuarine and coastal areas is given. Problems associated with these uses are discussed, and data needs for intelligent management of these valuable areas are outlined. Suspended sediment measurements are seen to be one of the greatest needs. To help understand the complexity of the problem, a brief discussion of sediment mechanics is given, including sediment sources, characteristics, and transport. The impact of sediment mechanics on its direct measurement (sampling and analysis) is indicated, along with recommendations for directly obtaining representative data. Indirect measurement of suspended sediment by remote sensors is discussed both theoretically and in the light of some recent experiences. The need for an integrated, multidisciplinary program to solve the problem of quantitatively measuring suspended sediment with remote sensors is stressed, and several important considerations of such a program and benefits to be derived therefrom are briefly addressed.

  11. Numerical noise in ocean and estuarine models

    USGS Publications Warehouse

    Walters, R.; Carey, G.F.

    1984-01-01

    Approximate methods for solving the shallow water equations may lead to solutions exhibiting large fictitious, numerically-induced oscillations. The analysis of the discrete dispersion relation and modal solutions of small wavelengths provides a powerful technique for assessing the sensitivity of alternative numerical schemes to irregular data which may lead to such oscillatory numerical noise. For those schemes where phase speed vanishes at a finite wavenumber or there are multiple roots for wavenumber, oscillation modes can exist which are uncoupled from the dynamics of the problem. The discrete modal analysis approach is used here to identify two classes of spurious oscillation modes associated respectively with the two different asymptotic limits corresponding to estuarine and large scale ocean models. The analysis provides further insight into recent numerical results for models which include large spatial scales and Coriolis acceleration. ?? 1984.

  12. Bathymetric effects on estuarine plume dynamics

    NASA Astrophysics Data System (ADS)

    Lee, Jungwoo; Valle-Levinson, Arnoldo

    2013-04-01

    influence of bathymetry on an estuary plume at an estuary-shelf transition is studied with a three-dimensional ocean circulation model. To understand the response of the plume to bathymetry, several types of estuarine shapes and shelf geometries were adopted in this numerical study. The channel's shape and its width-to-depth aspect ratio affected the fate of the plume by determining flow characteristics inside the estuary. Moreover, the bathymetry of the shelf such as the shelf slope and the direction of a submarine channel defined the plume characteristics on the shelf. An estuarine channel with a triangular cross section generated relatively stronger exchange flows at midestuary than a rectangular cross section, which resulted in a larger surface plume over the shelf. The extension of the submarine channel onto the shelf favored increased plume water transport out to the shelf, a result of reduced frictional effects on the shelf. The orientation of the submarine channel changed the direction of the plume over the shelf, with no additional external forces. Two fronts developed at the edges of the submarine channel because of enhanced lateral shears in the flow. When the estuary was relatively wide compared to the internal Rossby radius (Kelvin number Ke ≥ 5), or when the relative strength of the freshwater discharge compared to the estuary width was weak (Rossby number Ro ≤ 0.05), the coastal plume did not expand up-shelf. In fact, results indicated that freshwater up-shelf transport in a coastal current, moving against Coriolis' accelerations, was proportional to Ro.

  13. Insights on the Optical Properties of Estuarine DOM - Hydrological and Biological Influences.

    PubMed

    Santos, Luísa; Pinto, António; Filipe, Olga; Cunha, Ângela; Santos, Eduarda B H; Almeida, Adelaide

    2016-01-01

    Dissolved organic matter (DOM) in estuaries derives from a diverse array of both allochthonous and autochthonous sources. In the estuarine system Ria de Aveiro (Portugal), the seasonality and the sources of the fraction of DOM that absorbs light (CDOM) were inferred using its optical and fluorescence properties. CDOM parameters known to be affected by aromaticity and molecular weight were correlated with physical, chemical and meteorological parameters. Two sites, representative of the marine and brackish water zones of the estuary, and with different hydrological characteristics, were regularly surveyed along two years, in order to determine the major influences on CDOM properties. Terrestrial-derived compounds are the predominant source of CDOM in the estuary during almost all the year and the two estuarine zones presented distinct amounts, as well as absorbance and fluorescence characteristics. Freshwater inputs have major influence on the dynamics of CDOM in the estuary, in particular at the brackish water zone, where accounted for approximately 60% of CDOM variability. With a lower magnitude, the biological productivity also impacted the optical properties of CDOM, explaining about 15% of its variability. Therefore, climate changes related to seasonal and inter-annual variations of the precipitation amounts might impact the dynamics of CDOM significantly, influencing its photochemistry and the microbiological activities in estuarine systems. PMID:27195702

  14. Insights on the Optical Properties of Estuarine DOM – Hydrological and Biological Influences

    PubMed Central

    Santos, Luísa; Pinto, António; Filipe, Olga; Cunha, Ângela; Santos, Eduarda B. H.

    2016-01-01

    Dissolved organic matter (DOM) in estuaries derives from a diverse array of both allochthonous and autochthonous sources. In the estuarine system Ria de Aveiro (Portugal), the seasonality and the sources of the fraction of DOM that absorbs light (CDOM) were inferred using its optical and fluorescence properties. CDOM parameters known to be affected by aromaticity and molecular weight were correlated with physical, chemical and meteorological parameters. Two sites, representative of the marine and brackish water zones of the estuary, and with different hydrological characteristics, were regularly surveyed along two years, in order to determine the major influences on CDOM properties. Terrestrial-derived compounds are the predominant source of CDOM in the estuary during almost all the year and the two estuarine zones presented distinct amounts, as well as absorbance and fluorescence characteristics. Freshwater inputs have major influence on the dynamics of CDOM in the estuary, in particular at the brackish water zone, where accounted for approximately 60% of CDOM variability. With a lower magnitude, the biological productivity also impacted the optical properties of CDOM, explaining about 15% of its variability. Therefore, climate changes related to seasonal and inter-annual variations of the precipitation amounts might impact the dynamics of CDOM significantly, influencing its photochemistry and the microbiological activities in estuarine systems. PMID:27195702

  15. The interdisciplinary marine system of the Amundsen Sea, Southern Ocean: Recent advances and the need for sustained observations

    NASA Astrophysics Data System (ADS)

    Meredith, Michael P.; Ducklow, Hugh W.; Schofield, Oscar; Wåhlin, Anna; Newman, Louise; Lee, SangHoon

    2016-01-01

    The Southern Ocean exerts a profound influence on the functioning of the Earth System, in part because its location and unique bathymetric configuration enable direct linkages to the other major ocean basins (Ganachaud and Wunsch, 2000; Lumpkin and Speer, 2007). It is the site of the world's largest current system, the Antarctic Circumpolar Current (ACC), which transfers waters and climatically/ecologically-important tracers between the Atlantic, Indian and Pacific Oceans (Rintoul et al., 2001). In addition to the strong horizontal connectivity, the ACC is also characterized by a vigorous overturning circulation, which upwells warm, nutrient-rich waters from intermediate depth to the surface, where they are modified by interactions with the atmosphere and cryosphere to form new water masses, some of which are lighter and others more dense (Marshall and Speer, 2012). This overturning circulation structures the Southern Ocean both horizontally and vertically, dictates the levels of its communication with the rest of the global ocean, and is a fundamental control on the sequestration of carbon from the atmosphere into the ocean interior (Sallée et al., 2012). In some locations, the upwelled waters can intrude onto the Antarctic shelves, supplying heat and nutrients to the shallower regions. This is believed to be especially effective in west Antarctica, where the southern edge of the ACC moves close to the shelf break (Martinson, 2011; Orsi et al., 1995; Thoma et al., 2008).

  16. Progress and Challenges in Coupled Hydrodynamic-Ecological Estuarine Modeling

    EPA Science Inventory

    Numerical modeling has emerged over the last several decades as a widely accepted tool for investigations in environmental sciences. In estuarine research, hydrodynamic and ecological models have moved along parallel tracks with regard to complexity, refinement, computational po...

  17. LANDSAT ESTUARINE WATER QUALITY ASSESSMENT OF SILVICULTURE AND DREDGING ACTIVITIES

    EPA Science Inventory

    This report describes the application of Landsat multispectral scanning to estuarine water quality, with specific reference to dredging and silviculture practices. Water quality data collected biweekly since 1972 in the Apalachicola, Bay, Florida, by Florida State University, and...

  18. RESPONSES OF EXPERIMENTAL ESTUARINE COMMUNITIES TO CONTINUOUS CHLORINATION

    EPA Science Inventory

    The effects of continuous chlorination (as NaOCl) on estuarine benthic organisms were investigated with plankton-derived experimental communities. Twelve consecutive studies were conducted, each of which consisted of approximately 60 days colonization periods from flowing estuari...

  19. Connecting fishery sustainability to estuarine habitats and nutrient loading

    EPA Science Inventory

    The production of several important fishery species depends on critical estuarine habitats, including seagrasses and salt marshes. Relatively simple models can be constructed to relate fishery productivity to the extent and distribution of these habitats by linking fishery-depend...

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

    EPA Science Inventory

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

  1. Evaluation of commercial cotton harvesting systems in the southern high plains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cotton production practices have changed in the Southern High Plains of the US over the last decade resulting in increased yeilds and improved fiber quality. Moreover, the majority of US cotton now competes in a global fiber market that demands higher quality fiber for ring spun yarn than the former...

  2. Formation of albitite-hosted uranium within IOCG systems: the Southern Breccia, Great Bear magmatic zone, Northwest Territories, Canada

    NASA Astrophysics Data System (ADS)

    Montreuil, Jean-François; Corriveau, Louise; Potter, Eric G.

    2015-03-01

    Uranium and polymetallic U mineralization hosted within brecciated albitites occurs one kilometer south of the magnetite-rich Au-Co-Bi-Cu NICO deposit in the southern Great Bear magmatic zone (GBMZ), Canada. Concentrations up to 1 wt% U are distributed throughout a 3 by 0.5 km albitization corridor defined as the Southern Breccia zone. Two distinct U mineralization events are observed. Primary uraninite precipitated with or without pyrite-chalcopyrite ± molybdenite within magnetite-ilmenite-biotite-K-feldspar-altered breccias during high-temperature potassic-iron alteration. Subsequently, pitchblende precipitated in earthy hematite-specular hematite-chlorite veins associated with a low-temperature iron-magnesium alteration. The uraninite-bearing mineralization postdates sodic (albite) and more localized high-temperature potassic-iron (biotite-magnetite ± K-feldspar) alteration yet predates potassic (K-feldspar), boron (tourmaline) and potassic-iron-magnesium (hematite ± K-feldspar ± chlorite) alteration. The Southern Breccia zone shares attributes of the Valhalla (Australia) and Lagoa Real (Brazil) albitite-hosted U deposits but contains greater iron oxide contents and lower contents of riebeckite and carbonates. Potassium, Ni, and Th are also enriched whereas Zr and Sr are depleted with respect to the aforementioned albitite-hosted U deposits. Field relationships, geochemical signatures and available U-Pb dates on pre-, syn- and post-mineralization intrusions place the development of the Southern Breccia and the NICO deposit as part of a single iron oxide alkali-altered (IOAA) system. In addition, this case example illustrates that albitite-hosted U deposits can form in albitization zones that predate base and precious metal ore zones in a single IOAA system and become traps for U and multiple metals once the tectonic regime favors fluid mixing and oxidation-reduction reactions.

  3. Site/Systems Operations, Maintenance and Facilities Management of the Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) Cloud and Radiation Testbed (CART) Site

    SciTech Connect

    Wu, Susan

    2005-08-01

    This contract covered the site/systems operations, maintenance, and facilities management of the DOE Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) Cloud and Radiation Testbed (CART) Site.

  4. Facies architecture and depositional environments of the Upper Cretaceous Kaiparowits Formation, southern Utah

    NASA Astrophysics Data System (ADS)

    Roberts, Eric M.

    2007-04-01

    The Kaiparowits Formation is an unusually thick package of Upper Cretaceous (late Campanian) strata exposed in Grand Staircase-Escalante National Monument of southern Utah, USA. The formation was deposited within the rapidly subsiding Cordilleran foreland basin as part of a thick clastic wedge derived from sources in the Sevier orogenic belt, thrust sheets in southeastern Nevada and southern California, and the Mogollon slope in southwestern Arizona. Channel systems in the Kaiparowits Formation shifted from northeastward to southeastward flow over time, and for a short period of time, sea level rise in the Western Interior Seaway resulted in tidally influenced rivers and/or estuarine systems. Thick floodbasin pond deposits, large suspended-load channels, and poorly developed, hydromorphic paleosols dominate the sedimentary record, and all are suggestive of a relatively wet, subhumid alluvial system. This is supported by extremely rapid sediment accumulation rates (41 cm/ka), and high diversity and abundance of aquatic vertebrate and invertebrate fossils. Facies and architectural analysis was performed on the Kaiparowits Formation, resulting in the identification of nine distinct facies associations: 1) intraformational conglomerate, 2) mollusc-shell conglomerate, 3) major tabular sandstone, 4) major lenticular sandstone, 5) minor tabular and lenticular sandstone, 6) finely laminated, calcareous siltstone, 7) inclined heterolithic sandstone and mudstone, 8) sandy mudstone, and 9) carbonaceous mudstone. These facies associations are interpreted as: 1) channel lags, 2) rare channel-hosted storm beds, 3) meandering channels, 4) anastomosing channels, 5) crevasse splays and crevasse channels, 6) lakes, 7) tidally influenced fluvial and/or estuarine channels, 8) mud-dominated floodplains, and 9) swamps and oxbow lakes. Based on this analysis, the formation is subdivided into three informal units, representative of gross changes in alluvial architecture, including facies

  5. Effects of climate change on suitable rice cropping areas, cropping systems and crop water requirements in southern China

    DOE PAGESBeta

    Ye, Qing; Yang, Xiaoguang; Dai, Shuwei; Chen, Guangsheng; Li, Yong; Zhang, Caixia

    2015-06-05

    Here, we discuss that rice is one of the main crops grown in southern China. Global climate change has significantly altered the local water availability and temperature regime for rice production. In this study, we explored the influence of climate change on suitable rice cropping areas, rice cropping systems and crop water requirements (CWRs) during the growing season for historical (from 1951 to 2010) and future (from 2011 to 2100) time periods. The results indicated that the land areas suitable for rice cropping systems shifted northward and westward from 1951 to 2100 but with different amplitudes.

  6. Joint NOAA/NWS/USGS prototype debris flow warning system for recently burned areas in Southern California

    USGS Publications Warehouse

    Restrepo, P.; Jorgensen, D.P.; Cannon, S.H.; Costa, J.; Laber, J.; Major, J.; Martner, B.; Purpura, J.; Werner, K.

    2008-01-01

    Debris flows, also known as mudslides, are composed gravity-driven mixtures of sediment and water that travel through steep channels, over open hillslopes, and the like. Addressing this issue, US Geological Survey (USGS) and NOAA have established a debris-flow warning system that has the ability to monitor and forecast precipitation and issue timely weather hazard warning. In 2005, this joint NOAA-USGS prototype debris-flow warning system was issued in Southern California and as a result, it has provided valuable information to emergency managers in affected communities.

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

    EPA Science Inventory

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

  8. Electromagnetic outline of the Solfatara-Pisciarelli hydrothermal system, Campi Flegrei (Southern Italy)

    NASA Astrophysics Data System (ADS)

    Troiano, Antonio; Giulia Di Giuseppe, Maria; Patella, Domenico; Troise, Claudia; De Natale, Giuseppe

    2014-05-01

    We describe the results from a combined CSAMT and MT survey carried out in the Solfatara-Pisciarelli area, located in the central part of the Campi Flegrei composite caldera, west of Naples, Southern Italy. The Solfatara-Pisciarelli area represents the most active zone within the CF area, in terms of hydrothermal manifestations and local seismicity. Since 1969, the caldera is experiencing ground deformation, seismicity and geochemical fluid changes, which are particularly evident in this area. A 1 km long, nearly W-E directed CSAMT-MT profile crossing the fumaroles field was carried out with the aim of deducting an EM model of the structural setting of the hydrothermal system in the first 3 km depth. An interpretation of the EM modelled section is given in this paper, taking advantage from already existing seismic, gravity and geochemical data in the same area. Three well distinct EM zones have been outlined. The first EM zone is a very shallow, electrically conductive body localized beneath the westernmost segment of the profile, which, within a short distance of about 100 m, dips westwards from near surface down to some hundred metres depth. Mostly accounting for the very low resistivity (1-10 Ωm) and the exceedingly high values of vP/vS (>4), this shallow zone has been ascribed to a water-saturated, high-pressurized geothermal reservoir. The second EM zone, which has been localized below the west-central portion of the EM transect, appears as a composite body made of a nearly vertical plumelike structure that escapes at about 2.25 km depth from the top edge of the east side of a presumably horizontal platelike body. The plumelike structure rises up to the free surface in correspondence of the fumaroles field, whereas the platelike structure deepens at least down to the 3 km of maximum EM exploration depth. The combined interpretation of resistivity, wave velocity, gravity and geochemical data indicates the plumelike portion is likely associated with a steam

  9. Observations of the southern East Madagascar Current and undercurrent and countercurrent system

    NASA Astrophysics Data System (ADS)

    Nauw, J. J.; van Aken, H. M.; Webb, A.; Lutjeharms, J. R. E.; de Ruijter, W. P. M.

    2008-08-01

    In April 2001 four hydrographic sections perpendicular to the southern East Madagascar Current were surveyed as part of the Agulhas Current Sources Experiment. Observations with a vessel mounted and a lowered ADCP produced information on the current field while temperature, salinity, oxygen and nutrient data obtained with a CTD-Rosette system, gave information on the water mass structure of the currents southeast of Madagascar. The peak velocity in the pole-ward East Madagascar Current through these four sections had a typical magnitude of ˜110 cm/s, while the width of this current was of the order of 120 km. The mean pole-ward volume transport rate of this current during the survey above the 5°C isotherm was estimated to be 37 ± 10 Sv. On all four sections an undercurrent was observed at intermediate depths below the East Madagascar Current. Its equator-ward transport rate amounted to 2.8 ± 1.4 Sv. Offshore of the East Madagascar Current the shallow South Indian Ocean Countercurrent was observed. This eastward frontal jet coincided with the barotropic and thermohaline front that separates the saline Subtropical Surface Water from the fresher Tropical Surface Water in the East Madagascar Current. The near-surface geostrophic flow of the East Madagascar Current, derived from satellite altimetry data from 1992 to 2005, suggests a strong variability of this transport due to eddy variability and interannual changes. The long-term pole-ward mean transport of the East Madagascar Current, roughly estimated from those altimetry data amounts to 32 Sv. The upper-ocean water mass of the East Madagascar Current was very saline in 2001, compared to WOCE surveys from 1995. Comparison of our undercurrent data with those of the WOCE surveys in 1995 confirms that the undercurrent is a recurrent feature. Its water mass properties are relatively saline, due to the presence of water originating from the Red Sea outflow at intermediate levels. The saline water was advected from the

  10. Health system support for childbirth care in Southern Tanzania: results from a health facility census

    PubMed Central

    2013-01-01

    Background Progress towards reaching Millennium Development Goals four (child health) and five (maternal health) is lagging behind, particularly in sub-Saharan Africa, despite increasing efforts to scale up high impact interventions. Increasing the proportion of birth attended by a skilled attendant is a main indicator of progress, but not much is known about the quality of childbirth care delivered by these skilled attendants. With a view to reducing maternal mortality through health systems improvement we describe the care routinely offered in childbirth at dispensaries, health centres and hospitals in five districts in rural Southern Tanzania. We use data from a health facility census assessing 159 facilities in five districts in early 2009. A structural and operational assessment was undertaken based on staff reports using a modular questionnaire assessing staffing, work load, equipment and supplies as well as interventions routinely implemented during childbirth. Results Health centres and dispensaries attended a median of eight and four deliveries every month respectively. Dispensaries had a median of 2.5 (IQR 2–3) health workers including auxiliary staff instead of the recommended four clinical officer and certified nurses. Only 28% of first-line facilities (dispensaries and health centres) reported offering active management in the third stage of labour (AMTSL). Essential childbirth care comprising eight interventions including AMTSL, infection prevention, partograph use including foetal monitoring and newborn care including early breastfeeding, thermal care at birth and prevention of ophthalmia neonatorum was offered by 5% of dispensaries, 38% of health centres and 50% of hospitals consistently. No first-line facility had provided all signal functions for emergency obstetric complications in the previous six months. Conclusions Essential interventions for childbirth care are not routinely implemented in first-line facilities or hospitals. Dispensaries

  11. The Earthquake Early Warning System In Southern Italy: Performance Tests And Next Developments

    NASA Astrophysics Data System (ADS)

    Zollo, A.; Elia, L.; Martino, C.; Colombelli, S.; Emolo, A.; Festa, G.; Iannaccone, G.

    2011-12-01

    PRESTo (PRobabilistic and Evolutionary early warning SysTem) is the software platform for Earthquake Early Warning (EEW) in Southern Italy, that integrates recent algorithms for real-time earthquake location, magnitude estimation and damage assessment, into a highly configurable and easily portable package. The system is under active experimentation based on the Irpinia Seismic Network (ISNet). PRESTo processes the live streams of 3C acceleration data for P-wave arrival detection and, while an event is occurring, promptly performs event detection and provides location, magnitude estimations and peak ground shaking predictions at target sites. The earthquake location is obtained by an evolutionary, real-time probabilistic approach based on an equal differential time formulation. At each time step, it uses information from both triggered and not-yet-triggered stations. Magnitude estimation exploits an empirical relationship that correlates it to the filtered Peak Displacement (Pd), measured over the first 2-4 s of P-signal. Peak ground-motion parameters at any distance can be finally estimated by ground motion prediction equations. Alarm messages containing the updated estimates of these parameters can thus reach target sites before the destructive waves, enabling automatic safety procedures. Using the real-time data streaming from the ISNet network, PRESTo has produced a bulletin for about a hundred low-magnitude events occurred during last two years. Meanwhile, the performances of the EEW system were assessed off-line playing-back the records for moderate and large events from Italy, Spain and Japan and synthetic waveforms for large historical events in Italy. These tests have shown that, when a dense seismic network is deployed in the fault area, PRESTo produces reliable estimates of earthquake location and size within 5-6 s from the event origin time (To). Estimates are provided as probability density functions whose uncertainty typically decreases with time

  12. Development of a Dynamic Landslide Inventory Information System for Southern Kyrgyzstan

    NASA Astrophysics Data System (ADS)

    Golovko, Daria; Roessner, Sigrid; Behling, Robert; Wetzel, Hans-Ulrich; Kaufmann, Hermann

    2013-04-01

    Southern Kyrgyzstan is part of the tectonically active mountain ranges of the Tien Shan. The study area is located at the Eastern rim of the Fergana Basin representing a densely populated region where large landslides regularly endanger human lives and infrastructure. Therefore, GIS-based landslide susceptibility and hazard analysis is of great importance requiring detailed assessment of past landslide activity at regional scale. In Kyrgyzstan, information on past landslide activity is less available than in other more developed and researched regions of the world. Although landslide investigations were conducted since the 1950s, they have been drastically reduced since Kyrgyzstan's independence from the former Soviet Union in 1991 accompanied by loss of existing information. During the last years, information on landslides has been made publicly available mostly in form of derivatives, such as landslide hazard maps. All of these investigations have been limited to inhabited areas with known landslide danger. The presented research has the goal to develop a GIS-based approach for establishing a dynamic landslide inventory information system which allows efficient integration of the existing heterogeneous landslide data. They consist of reports prepared by Kyrgyz authorities as a result of field campaigns supported by visual interpretation of aerial photographs. These reports vary greatly in their spatial and temporal reliability as well as the format of the contained landslide data. This information has been complemented by multi-temporal satellite remote sensing data analysis carried out by the GFZ Potsdam aiming at interactive mapping of slopes affected by long-term complex landslide processes as well as developing an automated approach for landslide identification for the last 25 years. The used satellite remote sensing data provide a spatially continuous information base, partially with high temporal resolution, and thus enable creation of a dynamic landslide

  13. Quantitative relationships between watershed-scale stressors and estuarine condition for mid-Atlantic region

    SciTech Connect

    Paul, J.F.; Hale, S.S.; Comeleo, R.L.; Copeland, J.; August, P.V.

    1995-12-31

    A pilot project has been conducted that developed quantitative relationships between watershed-scale (landscape) stressors and sediment contamination for sub-estuaries within Chesapeake Bay. The landscape stressors, land use patterns (derived from classified, contemporary satellite imagery) and point source pollution, were spatially analyzed for each individual watershed of 25 sub-estuaries using a geographic information system. Sediment contamination data for the sub-estuaries, available from the Environmental Monitoring and Assessment Program (EMAP), were statistically reduced to one principal component for the metals and organics. Non-parametric statistical techniques were used to develop empirical relationships between sediment contamination and developed land (positive), herbaceous land (negative) and point source loadings (positive). These analyses have been extended to (1) include approximately 80 subestuaries across the mid-Atlantic region for which EMAP data were available, and (2) relate landscape stressors with estuarine condition. The measure of estuarine condition was an index of benthic quality developed by EMAP. The only available land use data set for the entire mid-Atlantic region was from US Geological Survey Land Use Data Analysis database, which is of 1970s vintage. Because of the dramatic differences in spatial area of the sub-estuaries in the mid-Atlantic region, adjustments for differing hydrologic regimes had to be factored into the analysis. Results indicate that it is possible to develop relationships between watershed-scale stressors and estuarine condition across large geographic regions.

  14. Modeling the Effects of Tidal Energy Extraction on Estuarine Hydrodynamics in a Stratified Estuary

    SciTech Connect

    Yang, Zhaoqing; Wang, Taiping

    2013-08-15

    A three-dimensional coastal ocean model with a tidal turbine module was used in this paper to study the effects of tidal energy extraction on temperature and salinity stratification and density driven two-layer estuarine circulation. Numerical experiments with various turbine array configurations were carried out to investigate the changes in tidally mean temperature, salinity and velocity profiles in an idealized stratified estuary that connects to coastal water through a narrow tidal channel. The model was driven by tides, river inflow and sea surface heat flux. To represent the realistic size of commercial tidal farms, model simulations were conducted based on a small percentage of the total number of turbines that would generate the maximum extractable energy in the system. Model results indicated that extraction of tidal energy will increase the vertical mixing and decrease the stratification in the estuary. Extraction of tidal energy has stronger impact on the tidally-averaged salinity, temperature and velocity in the surface layer than the bottom. Energy extraction also weakens the two-layer estuarine circulation, especially during neap tides when tidal mixing the weakest and energy extraction is the smallest. Model results also show that energy generation can be much more efficient with higher hub height with relatively small changes in stratification and two-layer estuarine circulation.

  15. Relative importance of estuarine nurseries for species of the genus Diplodus (Sparidae) along the Portuguese coast

    NASA Astrophysics Data System (ADS)

    Vinagre, C.; Cabral, H. N.; Costa, M. J.

    2010-01-01

    The relative importance of estuarine nursery areas for species of the genus Diplodus and their relations with several environmental variables was evaluated along the Portuguese coast. Nine estuarine systems were sampled with beam trawl surveys. Species of the genus Diplodus were only present in estuaries south of the Ria de Aveiro (40°38'). A latitudinal gradient of increasing species richness and abundance towards the south was found. Estuarine nurseries of Diplodus vulgaris, Diplodus sargus and Diplodus puntazzo were characterized by mud substrate, lower salinity and lower dissolved oxygen, with the exception of Ria Formosa. Diplodus bellottii was associated with estuaries with large areas and high volumes, the Tejo and the Sado. Diplodus bellottii nursery grounds were characterized by low depth. Diplodus annularis was associated with seagrass and saltmarsh habitats, certainly because it is the only species of the genus Diplodus which recruits exclusively to seagrass meadows. Diplodus annularis nursery grounds were also characterized by sand substrate, higher salinity and higher dissolved oxygen. Niche breath varied widely amongst species and location. Diplodus vulgaris generally presented the highest values of niche breath, except when D. bellottii was present. Niche overlap was not high, the highest value being that between D. vulgaris and D. sargus in the Mira estuary, with 76% spatial niche overlap. Considerations were made on these species progress towards the north in a climate warming context, taking into account the habitat associations described here.

  16. Geochemical and isotopic characterization of groundwater origins in a Mediterranean karst system (southern France)

    NASA Astrophysics Data System (ADS)

    Seidel, J. L.; Ladouche, B.; Batiot-Guilhe, C.

    2013-12-01

    Geochemical and isotopic ratio (11B/10B and 87Sr/86Sr) results are reported for better determining the groundwater origins in the Lez Karst system (southern France). The Lez spring is the main perennial outlet of the system and supplies with drinking water the metropolitan area of Montpellier. According to the hydrodynamic conditions, five water-types discharge at the Lez spring with important mineralization fluctuations (Caetano Bicalho et al., 2012). This geochemical response suggests that hydrodynamics targets groundwater circulation, resulting from different water end-member solicitation and mixing. Previous studies using conventional natural tracers do not succeed to identify all the water compartments supporting the flow during the hydrologic cycle (Marjolet & Salado, 1977; Joseph et al., 1988) and to explain the mineralization variation of the Lez spring. The present study combines a basic geochemical survey data with boron and strontium isotope ratio data for a better characterization of the Lez spring geochemical functioning. Groundwater samples were collected at the Lez spring and surrounding springs and wells under different hydrologic conditions from 2009 to 2011. Major, trace and rare earth elements were determined at AETE analytical platform (OREME, Univ. Montpellier 2) by ionic chromatography and Q-ICP-MS respectively. d11B and 87Sr/86Sr were determined at BRGM/MMA Orleans by TIMS. The geochemical survey has been extended at a larger scale by sampling the main geochemical end- members already identified to replace the Lez spring waters in the regional geochemical context. From this geochemical study, valuable informations have been provided on the reservoir types and water origins flowing in high and low stage periods. For the highly mineralized waters occurring in the fall first rainy events or severe low stages, a deep contribution is highlighted but B and Sr isotopic data do not ascertain the two Triassic end-members (halite or gypsum) as possible

  17. The influence of the Kennebec River discharge on estuarine and reverse estuarine flow in eastern Casco Bay, Gulf of Maine

    NASA Astrophysics Data System (ADS)

    Wolovick, M.; Laine, E.; Roesler, C.; Teegarden, G.

    2008-12-01

    Harpswell Sound and the New Meadows estuary are narrow coastal embayments on the eastern side of Casco Bay, in the Gulf of Maine. Hourly oceanographic data was collected at both locations, including ADCP profiles of current velocity vs. depth. It was found that net circulation in both inlets displays both estuarine and inverse estuarine characteristics at various times. During periods of low discharge from the neighboring Kennebec River there is little connection between the two inlets, with New Meadows developing a three- layered circulation regime and Harpswell Sound having periods of negligible net flow punctuated by brief wind-driven events. However, when the discharge of the Kennebec River is high both inlets experience considerable freshening of surface water with corresponding increases in vertical stratification. In addition both inlets act in concert, experiencing near-simultaneous alternation between estuarine and inverse estuarine current regimes of relatively high strength. It is hypothesized that this coordinated reverse estuarine flow is caused by the passage of the leading edge of a bolus of fresher Kennebec discharge past the entrances of the inlets. Water flowing down the sloping surface of this bolus is deflected by the Coriolis force, running into the inlets at the surface and triggering a compensating outflow at depth. Conversely, coordinated estuarine flow is caused by the passage of the trailing edge of the bolus past the entrances, causing the sea surface slope to switch direction.

  18. Southern Ocean frontal system changes precede Antarctic ice sheet growth during the middle Miocene

    NASA Astrophysics Data System (ADS)

    Kuhnert, Henning; Bickert, Torsten; Paulsen, Harald

    2009-07-01

    The middle Miocene climate approximately 14 Ma ago was characterized by the glaciation of Antarctica, deep-ocean cooling and variations in the global carbon cycle. Although the Southern Ocean underwent significant oceanographic changes, there is limited information on their spatial extent and timing. However, such knowledge is crucial for understanding the role of the Southern Ocean and the Antarctic Circumpolar Current (ACC) for Antarctic glaciation and the coupling between the ocean and continental climate. We have reconstructed surface temperatures and seawater oxygen isotopes at Ocean Drilling Program (ODP) Site 1092 in the Polar Frontal Zone of the Atlantic sector of the Southern Ocean from foraminiferal oxygen isotopes ( δ18O) and magnesium to calcium ratios (Mg/Ca). Sea surface cooling by ~ 4 °C and freshening indicated by the ~ 1‰ reduction of seawater δ18O ( δ18O sw) at 14.2 Ma precede the major step in Antarctic ice sheet growth at 13.8-13.9 Ma. This pattern qualitatively mirrors previous findings from the Pacific sector, and we interpret the surface hydrographic changes to reflect the circum-Antarctic northward shift of the Southern Ocean fronts and specifically at Site 1092 the passage of the Subantarctic Front. The magnitude of change in reconstructed δ18O sw requires a δ18O sw: salinity gradient significantly higher than the modern value (~ 0.52‰) and it possibly exceeded 1.1‰. This implies the Polar Frontal Zone was influenced by freshwater derived from Antarctica, which in turn confirms higher than modern continental precipitation. The latter has previously been suggested to have contributed to Antarctic glaciation.

  19. Ecology of Albemarle Sound, North Carolina: an estuarine profile

    SciTech Connect

    Copeland, B.J.; Hodson, R.G.; Riggs, S.R.; Easley, J.E. Jr.

    1983-09-01

    Albemarle Sound, a large oligohaline estuary in northeastern North Carloina, constitutes a significant portion of North Carolina's coastal system. It is shallow, wind dominated, and strongly influenced by freshwater inflow. These conditions, combined with limited oceanic access and exchange, maintain fresh- to brackish water conditions throughout most of the estuary during the year. The nekton are the most well-known biological component of this extensive estuarine system. Albemarle Sound is an important nursery area for a number of anadromous and migratory fish as well as the blue crab and supports fisheries for many of these species. Other biological components (phytoplankton, zooplankton, and benthos) in the estuary are less well studied. Declining fisheries, algal blooms in freshwater tributaries, and changing patterns of land and water use are among the critical issues facing managers of Albemarle Sound. This report discusses current steps being taken toward holistic management and provides a state-of-the-art information base and ecological synthesis of the estuary and its watershed. 89 references, 50 figures, 19 tables.

  20. Inverse estimation of parameters for an estuarine eutrophication model

    SciTech Connect

    Shen, J.; Kuo, A.Y.

    1996-11-01

    An inverse model of an estuarine eutrophication model with eight state variables is developed. It provides a framework to estimate parameter values of the eutrophication model by assimilation of concentration data of these state variables. The inverse model using the variational technique in conjunction with a vertical two-dimensional eutrophication model is general enough to be applicable to aid model calibration. The formulation is illustrated by conducting a series of numerical experiments for the tidal Rappahannock River, a western shore tributary of the Chesapeake Bay. The numerical experiments of short-period model simulations with different hypothetical data sets and long-period model simulations with limited hypothetical data sets demonstrated that the inverse model can be satisfactorily used to estimate parameter values of the eutrophication model. The experiments also showed that the inverse model is useful to address some important questions, such as uniqueness of the parameter estimation and data requirements for model calibration. Because of the complexity of the eutrophication system, degrading of speed of convergence may occur. Two major factors which cause degradation of speed of convergence are cross effects among parameters and the multiple scales involved in the parameter system.

  1. Fostering traditional health systems and ethnomedicine practices through a holistic approach: a pioneering community strategy from Southern India.

    PubMed

    Torri, Maria Costanza

    The ever-presence of traditional medicine and of medical practitioners in remote areas of the world is well documented by anthropological studies. However, the social, cultural, and environmental factors influencing health and traditional health systems have been analyzed separately, ignoring the interlinkages existing between them and the resulting synergies as well as the impact these will have on the multiple aspects of local communities. This case study attempts to overcome this shortcoming, by investigating the interrelationships between biodiversity conservation and the practice of ethnomedicine in Southern India as a basis to implement primary health care, enhance local livelihoods, and contribute to poverty alleviation through community-based entrepreneurial activities. PMID:20353924

  2. The architecture of the porphyry-metal system as a prospecting stratagem in the Southern Rocky Mountains

    USGS Publications Warehouse

    Neuerburg, George J.

    1978-01-01

    A model of the porphyry-metal system characteristic of the consanguineous Cretaceous and Tertiary igneous rocks and associated ores of the southern Rocky Mountains is constructed from the bits and pieces exposed in the Colorado mineral belt and the San Juan volcanic field. Hydrothermally altered rocks in a part of the areas of mineralized rock associated with the Platoro caldera are matched against the model, to locate and to characterize latent mineral deposits for optimal prospecting and exploration. The latent deposits are two stockwork molybdenite deposits (porphyry-molybdenum) and one or two copper-gold-silver chimney deposits.

  3. Infilling of the Hudson River Estuary During the Late Holocene (3000ka to Present): Implications for Estuarine Stratigraphic Models

    NASA Astrophysics Data System (ADS)

    McHugh, C. M.; Pekar, S. F.; Ryan, W. B.; Carbotte, S.; Bell, R.; Burckle, L.

    2002-12-01

    Estuaries are widely preserved in the geologic record and the estuarine fill, contained between non-marine sediment, provides an excellent temporal marker for continental margin studies. Estuarine stratigraphic models have provided a framework within which to interpret the estuarine fill. However, estuarine systems differ greatly in the shape of their valleys, the tectonic boundaries they cross, and in sediment supply so that their position in the geologic record may be out of sequence with that predicted by the models. New insights into estuarine systems and models are provided by the Hudson River Estuary (HRE; New York State) based on >150 cores and grab sediment samples and acoustic images documenting in great detail how the HRE filled its earlier excavated valley during the latest Holocene (3ka to present). Radiocarbon and 137-Cs radioisotope ages, borehole, and core data document the sedimentation patterns of the estuary. Diatom assemblages provide estimates of the shallowing-upwards of the estuary as its basin filled with sediments. The three areas of the stratigraphic model present in the HRE, include zones formed within inner fluvial and outer marine areas, (containing coarse-grained, sands and gravels), and a central area (containing fine-grained, silts and clays), that are nearly filled with little room for sediments to accumulate at or near sea-level. This has resulted in sedimentary bypass for almost the entire length the estuary. South of Kingston, fine-grained sediments have ceased accumulating when the bottom approaches wave base. Upstream from Kingston, final filling occurs as sediments fill in the remaining accommodation, forming islands. This should result in the export of sediment to the coastal zone. Instead, localized areas of sediment trapping still exist, which are related to the Hudson Valley Highlands and to the location of the estuarine turbidity maximum that hold large volumes of sediment. As a result minor volumes of Recent sediment are

  4. Electromagnetic outline of the Solfatara-Pisciarelli hydrothermal system, Campi Flegrei (Southern Italy)

    NASA Astrophysics Data System (ADS)

    Troiano, A.; Di Giuseppe, M. G.; Patella, D.; Troise, C.; De Natale, G.

    2014-05-01

    We describe the results from a combined controlled source audio magnetotelluric (CSAMT) and natural source magnetotelluric (MT) survey carried out in the Solfatara-Pisciarelli (S-P) area, located in the central part of the Campi Flegrei (CF) composite caldera, west of Naples, Southern Italy. The S-P area represents the most active zone within the CF caldera, in terms of hydrothermal manifestations and local seismicity. Since 1969, the CF caldera is experiencing ground deformation, seismicity and geochemical fluid changes, which are particularly evident in the S-P area. A 1 km long, nearly W-E directed CSAMT-MT profile crossing the fumarole field was carried out in the S-P area with the aim of deducting a resistivity model of the structural setting of the hydrothermal system in the first 3 km depth. An interpretation of the modelled section across the profile is given in this paper, taking advantage from already existing seismic, gravity and geochemical data in the same area. Three well distinct zones have been outlined. The first zone is a very shallow, electrically conductive body localized beneath the westernmost segment of the profile, which, within a short distance of about 100 m, dips westwards from near surface down to some hundred metres in depth. Mostly accounting for the very low resistivity (1-10 Ω m) and the exceedingly high values of vP/vS (> 4), this shallow zone has been ascribed to a water-saturated, high-pressurized geothermal reservoir. The second zone, which has been localized below the west-central portion of the CSAMT-MT transect, appears as a composite body made up of a nearly vertical plumelike structure that escapes at about 2.25 km depth from the top edge of the east side of a presumably horizontal platelike body. The plumelike structure rises up to the free surface in correspondence of the fumarole field, whereas the platelike structure deepens at least down to the 3 km of maximum exploration depth. The combined interpretation of

  5. Moving sands along a headland-embayed beach system (Algarve, Southern Portugal)

    NASA Astrophysics Data System (ADS)

    Oliveira, Sónia; Horta, João; Nascimento, Ana; Gomes, Ana; Veiga-Pires, Cristina; Moura, Delminda

    2015-04-01

    Resilience of embayed and pocket beaches located at the southernmost coast of Portugal is currently a major question to coastal management of this region. In fact, several among those beaches have been artificially fed aiming to increase the width of the beach allowing people to maintain a safe distance to the unstable rocky cliffs. The sand is dredged from the offshore (ca. 2 miles from the shoreline) representing high costs for the Portuguese government. For how long will the artificial feeding solve the problem? Which beaches are worth being nourished taking into account the morphosedimentary processes? The present work is the result of a field experiment aiming to study the efficiency of the alongshore sedimentary transport between successive embayed beaches. The experiment was performed in the very indented rocky coast of the Algarve region (Southern Portugal) and comprised two field campaigns, both in 2014, during spring tides in March and November. The Algarve coast experiences a semi-diurnal meso-tidal regime ranging from 1.3 m during neap tides to 3.5 m at spring tides and the waves approach from WSW (232°) during 72% of observations along the year, almost normal to the study area shoreline. The wave and current characteristics (significant height-Hs and Period-T for waves, velocity and direction for currents) were measured during three and six tidal cycles respectively for the first and second campaign, using two pressure transducers and one electromagnetic current meter. We used sand painted with orange fluorescent dye (100 kg in March and 200 kg in November) as tracer to track the movement of the sand along the coast. The marked sand was placed on the beach face of the westernmost beach of the study area during the first low tide of each campaign. Following, hundreds of sediment samples were collected during low tide, through the monitored period, in the nodes of a georeferenced square mesh of 10 x 20 m covering three embayed beaches. Later in the

  6. Modelling a strike-slip fault system affecting porous carbonates in Favignana Island (Sicily, southern Italy)

    NASA Astrophysics Data System (ADS)

    Cilona, A.; Tondi, E.; Agosta, F.; Johnson, G.; Shackleton, R.

    2012-12-01

    Investigating the deformation processes as well as the characteristics and distribution of their end-products is a crucial issue to improve geo-fluid exploitation in carbonate reservoirs (≈50% of natural geo-fluids). Indeed, besides the primary controls on the petrophysical properties of limestones, which are due to nature and organization/shape of the constituent elements (i.e. grains, pores, cement, clay minerals), both containment and migration of fluids in these rocks are influenced by fault zones and fractures. In this contribution we integrate quantitative structural analysis and numerical modelling approaches aiming at testing a new workflow useful to create a 3D discrete fracture network (DFN) model of a reservoir starting from outcrop data collected in Favignana Island (Sicily, southern Italy). The presence of several quarries in the Island provides 3D exposures of ≈25 m-thick Lower-Pleistocene high-porosity grainstones crosscut by two conjugate sets of strike-slip faults. This fault system, documented by Tondi et al. (2012), is comprised of three types of structure: single compactive shear bands (CSB); zones of bands (ZB); and, faults. CSBs are narrow tabular features with porosity less than the surrounding host rocks, and have thicknesses and displacements on the order of a few mm. The growth process for these structures involves localizing further deformation within zones of closely-spaced CSBs and, possibly, along continuous slip surfaces within fault rocks overprinting older ZBs. The transitions from one growth step to another are recorded by different values of the dimensional parameters (i.e. length, thickness and displacement) for the structures. These transitions are also reflected by the ratios and distributions of the dimensional parameters. The DFN model was built by means of the Fracture Modelling module of the commercial software package Move from Midland Valley©. The analysis of an aerial photo was performed firstly to delimit the

  7. Ecotoxicology of bromoacetic acid on estuarine phytoplankton.

    PubMed

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

    2015-11-01

    Bromoacetic acid is formed when effluent containing chlorine residuals react with humics in natural waters containing bromide. The objective of this research was to quantify the effects of bromoacetic acid on estuarine phytoplankton as a proxy for ecosystem productivity. Bioassays were used to measure the EC50 for growth in cultured species and natural marine communities. Growth inhibition was estimated by changes in chlorophyll a concentrations measured by fluorometry and HPLC. The EC50s for cultured Thalassiosira pseudonana were 194 mg L(-1), 240 mg L(-1) for Dunaliella tertiolecta and 209 mg L(-1) for Rhodomonas salina. Natural phytoplankton communities were more sensitive to contamination with an EC50 of 80 mg L(-1). Discriminant analysis suggested that bromoacetic acid additions cause an alteration of phytoplankton community structure with implications for higher trophic levels. A two-fold EC50 decrease in mixed natural phytoplankton populations affirms the importance of field confirmation for establishing water quality criteria. PMID:26247379

  8. Composition of estuarine colloidal material: organic components

    USGS Publications Warehouse

    Sigleo, A.C.; Hoering, T.C.; Helz, G.R.

    1982-01-01

    Colloidal material in the size range 1.2 nm to 0.4 ??m was isolated by ultrafiltration from Chesapeake Bay and Patuxent River waters (U.S.A.). Temperature controlled, stepwise pyrolysis of the freeze-dried material, followed by gas chromatographic-mass spectrometric analyses of the volatile products indicates that the primary organic components of this polymer are carbohydrates and peptides. The major pyrolysis products at the 450??C step are acetic acid, furaldehydes, furoic acid, furanmethanol, diones and lactones characteristic of carbohydrate thermal decomposition. Pyrroles, pyridines, amides and indole (protein derivatives) become more prevalent and dominate the product yield at the 600??C pyrolysis step. Olefins and saturated hydrocarbons, originating from fatty acids, are present only in minor amounts. These results are consistent with the composition of Chesapeake phytoplankton (approximately 50% protein, 30% carbohydrate, 10% lipid and 10% nucleotides by dry weight). The pyrolysis of a cultured phytoplankton and natural particulate samples produced similar oxygen and nitrogencontaining compounds, although the proportions of some components differ relative to the colloidal fraction. There were no lignin derivatives indicative of terrestrial plant detritus in any of these samples. The data suggest that aquatic microorganisms, rather than terrestrial plants, are the dominant source of colloidal organic material in these river and estuarine surface waters. ?? 1982.

  9. Estuarine ecology of phenanthrene-degrading bacteria

    NASA Astrophysics Data System (ADS)

    Guerin, William F.; Jones, Galen E.

    1989-08-01

    Phenanthrene degrading bacteria were ubiquitously distributed in waters and sediments of the Great Bay Estuary, NH, as determined using a 14C-phenanthrene mineralization assay. Similar activities were observed in water samples collected in March and June when these were incubated at 18 °C even though ambient water temperatures were 1-4 °C and 10-22 °C, respectively. This observation indicated the constant presence of a mesophilic phenanthrene-degrading bacterial population in the estuary. Among water samples, the highest biodegradation activities were associated with samples collected downstream from a dredging operation which introduced high concentrations of coal tar PAH (polycyclic aromatic hydrocarbons) into the Cocheco River, and in areas receiving PAH from pleasure and commercial boating activities. Mid-estuarine maxima in biodegradation activity during both sampling trips suggested adaptation of the microbial flora to the salinities prevailing in the low turnover, high residence time portion of the Estuary at the time of sampling. Despite the hydrophobicity of phenanthrene, no correlation between biodegradation rates and particulate matter concentrations were observed. Similarly, concentrations of nutrients and dissolved and particulate organic matter correlated poorly with biodegradation rates. Better agreements between 14C-phenanthrene mineralization potentials and plate counts on a phenanthrene/toluene agar (PTA) medium were observed. Phenanthrene biodegradative activities and numbers of culturable bacteria growing on PTA were governed by the degree of previous exposure to PAH.

  10. Passive acoustic threat detection in estuarine environments

    NASA Astrophysics Data System (ADS)

    Borowski, Brian; Sutin, Alexander; Roh, Heui-Seol; Bunin, Barry

    2008-04-01

    The Maritime Security Laboratory (MSL) at Stevens Institute of Technology supports research in a range of areas relevant to harbor security, including passive acoustic detection of underwater threats. The difficulties in using passive detection in an urban estuarine environment include intensive and highly irregular ambient noise and the complexity of sound propagation in shallow water. MSL conducted a set of tests in the Hudson River near Manhattan in order to measure the main parameters defining the detection distance of a threat: source level of a scuba diver, transmission loss of acoustic signals, and ambient noise. The source level of the diver was measured by comparing the diver's sound with a reference signal from a calibrated emitter placed on his path. Transmission loss was measured by comparing noise levels of passing ships at various points along their routes, where their distance from the hydrophone was calculated with the help of cameras and custom software. The ambient noise in the Hudson River was recorded under varying environmental conditions and amounts of water traffic. The passive sonar equation was then applied to estimate the range of detection. Estimations were done for a subset of the recorded noise levels, and we demonstrated how variations in the noise level, attenuation, and the diver's source level influence the effective range of detection. Finally, we provided analytic estimates of how an array improves upon the detection distance calculated by a single hydrophone.

  11. Microgobius meeki as a potential bio-indicator of habitat disturbance in shallow estuarine areas: a useful tool for the assessment of estuarine quality.

    PubMed

    Reis-Filho, J A; Giarrizzo, T

    2016-07-01

    The relationships between changes in habitat quality (disturbed and undisturbed sites) and the population parameters (density, size distribution, reproductive activity and diet) of a goby Microgobius meeki were investigated in a tropical estuary to assess its value as an indicator of anthropogenic changes, predominantly the effects of sedimentation and mangrove removal in shallow estuarine areas. Fish sampling surveys were conducted bimonthly between June 2009 and May 2010 over the entire estuarine gradient of the Paraguaçu River estuary, located on the central Brazilian coast. A predictive model was developed to assess the population changes of this species in 10 other tropical estuaries with different dimensions, basin features and distinct levels of anthropogenic disturbance. General linear models were used to relate the population structure of M. meeki to sediment type, habitat type resulting from mangrove conservation status, anthropogenic pressure and environmental characteristics such as salinity, dissolved oxygen concentrations and temperature. Sediment type and the presence of mangrove forests were the most effective predictors of local variability in the population structure of M. meeki. Individuals with mature gonads and high rates of feeding activity were associated predominantly with undisturbed habitats. Estuaries and estuarine sectors with high levels of sedimentation in shallow marginal areas, anthropogenic pressure from domestic and industrial effluents, and evidence of mangrove deforestation yielded the lowest capture rates of both juvenile and adult M. meeki. Based on these findings, M. meeki is identified as a potential indicator of the consequences of anthropogenic disturbance in transitional waters. A simple, but efficient collection protocol, in which overt signs of distress can be promptly observed is proposed. Testing the generality of this approach across different systems might prove useful in a broader conservation biology context. PMID

  12. Is there a "blind" strike-slip fault at the southern end of the San Jacinto Fault system?

    NASA Astrophysics Data System (ADS)

    Tymofyeyeva, E.; Fialko, Y. A.

    2015-12-01

    We have studied the interseismic deformation at the southern end of the San Jacinto fault system using Interferometric Synthetic Aperture Radar (InSAR) and Global Positioning System (GPS) data. To complement the continuous GPS measurements from the PBO network, we have conducted campaign-style GPS surveys of 19 benchmarks along Highway 78 in the years 2012, 2013, and 2014. We processed the campaign GPS data using GAMIT to obtain horizontal velocities. The data show high velocity gradients East of the surface trace of the Coyote Creek Fault. We also processed InSAR data from the ascending and descending tracks of the ENVISAT mission between the years 2003 and 2010. The InSAR data were corrected for atmospheric artifacts using an iterative common point stacking method. We combined average velocities from different look angles to isolate the fault-parallel velocity field, and used fault-parallel velocities to compute strain rate. We filtered the data over a range of wavelengths prior to numerical differentiation, to reduce the effects of noise and to investigate both shallow and deep sources of deformation. At spatial wavelengths less than 2km the strain rate data show prominent anomalies along the San Andreas and Superstition Hills faults, where shallow creep has been documented by previous studies. Similar anomalies are also observed along parts of the Coyote Creek Fault, San Felipe Fault, and an unmapped southern continuation of the Clark strand of the San Jacinto Fault. At wavelengths on the order of 20km, we observe elevated strain rates concentrated east of the Coyote Creek Fault. The long-wavelength strain anomaly east of the Coyote Creek Fault, and the localized shallow creep observed in the short-wavelength strain rate data over the same area suggest that there may be a "blind" segment of the Clark Fault that accommodates a significant portion of the deformation on the southern end of the San Jacinto Fault.

  13. Response of deformation patterns to reorganizations of the southern San Andreas fault system since ca. 1.5 Ma

    NASA Astrophysics Data System (ADS)

    Cooke, M. L.; Fattaruso, L.; Dorsey, R. J.; Housen, B. A.

    2015-12-01

    Between ~1.5 and 1.1 Ma, the southern San Andreas fault system underwent a major reorganization that included initiation of the San Jacinto fault and termination of slip on the extensional West Salton detachment fault. The southern San Andreas fault itself has also evolved since this time, with several shifts in activity among fault strands within San Gorgonio Pass. We use three-dimensional mechanical Boundary Element Method models to investigate the impact of these changes to the fault network on deformation patterns. A series of snapshot models of the succession of active fault geometries explore the role of fault interaction and tectonic loading in abandonment of the West Salton detachment fault, initiation of the San Jacinto fault, and shifts in activity of the San Andreas fault. Interpreted changes to uplift patterns are well matched by model results. These results support the idea that growth of the San Jacinto fault led to increased uplift rates in the San Gabriel Mountains and decreased uplift rates in the San Bernardino Mountains. Comparison of model results for vertical axis rotation to data from paleomagnetic studies reveals a good match to local rotation patterns in the Mecca Hills and Borrego Badlands. We explore the mechanical efficiency at each step in the evolution, and find an overall trend toward increased efficiency through time. Strain energy density patterns are used to identify regions of off-fault deformation and potential incipient faulting. These patterns support the notion of north-to-south propagation of the San Jacinto fault during its initiation. The results of the present-day model are compared with microseismicity focal mechanisms to provide additional insight into the patterns of off-fault deformation within the southern San Andreas fault system.

  14. Influence of organic carbon on estuarine benthic infauna of the US west coast

    EPA Science Inventory

    Total organic carbon (TOC) is often used as an indicator of eutrophication in estuarine environments. However, the determination of biologically relevant sediment TOC criteria to indicate estuarine condition is complicated by the relationship between TOC and grain size. Both va...

  15. Influence of organic carbon on estuarine benthic infauna of the US west coast - March 3, 2011

    EPA Science Inventory

    Total organic carbon (TOC) is often used as an indicator of eutrophication in estuarine environments. However, the determination of biologically relevant sediment TOC criteria to indicate estuarine condition is complicated by the relationship between TOC and grain size. Both va...

  16. Human mediated transport determines the non-native distribution of a dispersal limited estuarine invertebrate

    EPA Science Inventory

    Sessile invertebrates are common invaders of estuarine ecosystems. To expand their non-native ranges, these invasive taxa must contend with the geographically and ecologically discontinuous nature of estuarine habitats, in many cases without the benefit of highly dispersed larval...

  17. Redox states of underground brine system along the southern coast of the Laizhou Bay

    NASA Astrophysics Data System (ADS)

    Jiang, Xueyan; Yu, Zhigang; Ning, Jinsong; Chen, Hongtao; Mi, Tiezhu

    2008-05-01

    Underground brine samples were collected along the southern coast of the Laizhou Bay, Shangdong, China in two field investigations in 2003. The brines are confined in the Quaternary sediment and underwent a series of geochemical changes. The redox states of these brines were assessed qualitatively based on the measurements of Eh and redox-sensitive species such as DO, NO NO{3/-}, Mn2+, Fe2+, SO{4/2-} in the brines. The redox condition of the underground brine is anoxic, and the redox reactions that controlled the redox potential of brines should be Fe(III) reduction and sulfate reduction.

  18. Radial Velocity Studies of Southern Close Binary Stars. II. Spring/Summer Systems

    NASA Astrophysics Data System (ADS)

    Duerbeck, Hilmar W.; Rucinski, Slavek M.

    2007-01-01

    Radial velocity measurements and sine-curve fits to the orbital velocity variations are presented for 14 close binary stars, S Ant, TT Cet, TW Cet, AA Cet, RW Dor, UX Eri, YY Eri, BV Eri, CT Eri, SZ Hor, AD Phe, TY Pup, HI Pup, and TZ Pyx. All are double-lined binaries, and all except the last one are contact binaries. The orbital data must be considered preliminary because of the relatively small number of observations (6-12), a circumstance that is partly compensated by the good definition of the broadening functions used for the radial velocity determinations. Based on data obtained at the European Southern Observatory.

  19. Black Carbon in Estuarine and Coastal Ocean Dissolved Organic Matter

    NASA Technical Reports Server (NTRS)

    Mannino, Antonio; Harvey, H. Rodger

    2003-01-01

    Black carbon (BC) in ultrafiltered high-molecular-weight DOM (UDOM) was measured in surface waters of Delaware Bay, Chesapeake Bay and the adjacent Atlantic Ocean (USA) to ascertain the importance of riverine and estuarine DOM as a source of BC to the ocean. BC comprised 5-72% of UDOM-C (27+/-l7%) and on average 8.9+/-6.5% of dissolved organic carbon (DOC) with higher values in the turbid region of the Delaware Estuary and lower yields in the river and coastal ocean. The spatial and seasonal distributions of BC along the salinity gradient of Delaware Bay suggest that the higher levels of BC in surface water UDOM originated from localized sources, possibly from atmospheric deposition or released from resuspended sediments. Black carbon comprised 4 to 7% of the DOC in the coastal Atlantic Ocean, revealing that river-estuary systems are important exporters of colloidal BC to the ocean. The annual flux of BC from Delaware Bay UDOM to the Atlantic Ocean was estimated at 2.4x10(exp 10) g BC yr(exp -1). The global river flux of BC through DOM to the ocean could be on the order of 5.5x1O(exp 12)g BC yr (exp -1). These results support the hypothesis that the DOC pool is the intermediate reservoir in which BC ages prior to sedimentary deposition.

  20. The fate of fipronil in modular estuarine mesocosms.

    PubMed

    Walse, Spencer S; Pennington, Paul L; Scott, Geoffrey I; Ferry, John L

    2004-01-01

    The degradation and corresponding product manifold for the pesticide fipronil was determined in three replicate estuarine mesocosms. Aqueous fipronil concentrations rapidly decreased over the 672 h timescale of the experiment (95% removal). Loss was apparently first-order in fipronil, although there appeared to be a change in the removal mechanism after 96 h that corresponded to a dramatic slowdown in its disappearance. The reduction product of fipronil, fipronil sulfide, was not detected in the water column; however, it formed rapidly in sediments and was identified as the major product of fipronil degradation in the system (20% yield at 672 h, with respect to initial fipronil concentration). Fipronil sulfone is thought to form primarily via biological oxidation; and, although it was generated rapidly in the water column (10% yield), only trace amounts were detected in the sediment (1% yield). The direct photolysis product of fipronil, fipronil desulfinyl, was present in all samples; it formed rapidly in the water column (4% yield) and partitioned into the sediment phase (7% yield) over the course of the experiment. The mass balance on fipronil and associated products was 42% at 672 h. PMID:14737471

  1. Effects of an estuarine plume-associated bloom on the carbonate system in the lower reaches of the Pearl River estuary and the coastal zone of the northern South China Sea

    NASA Astrophysics Data System (ADS)

    Dai, Minhan; Zhai, Weidong; Cai, Wei-Jun; Callahan, Julie; Huang, Bangqin; Shang, Shaoling; Huang, Tao; Li, Xiaolin; Lu, Zhongming; Chen, Weifang; Chen, Zhaozhang

    2008-07-01

    We observed a phytoplankton bloom downstream of a large estuarine plume induced by heavy precipitation during a cruise conducted in the Pearl River estuary and the northern South China Sea in May-June 2001. The plume delivered a significant amount of nutrients into the estuary and the adjacent coastal region, and enhanced stratification stimulating a phytoplankton bloom in the region near and offshore of Hong Kong. A several fold increase (0.2-1.8 μg Chl L -1) in biomass (Chl a) was observed during the bloom. During the bloom event, the surface water phytoplankton community structure significantly shifted from a pico-phytoplankton dominated community to one dominated by micro-phytoplankton (>20 μm). In addition to increased Chl a, we observed a significant drawdown of pCO 2, biological uptake of dissolved inorganic carbon (DIC) and an associated enhancement of dissolved oxygen and pH, demonstrating enhanced photosynthesis during the bloom. During the bloom, we estimated a net DIC drawdown of 100-150 μmol kg -1 and a TAlk increase of 0-50 μmol kg -1. The mean sea-air CO 2 flux at the peak of the bloom was estimated to be as high as ˜-18 mmol m -2 d -1. For an average surface water depth of 5 m, a very high apparent biological CO 2 consumption rate of 70-110 mmol m -2 d -1 was estimated. This value is 2-6 times higher than the estimated air-sea exchange rate.

  2. Using nitrate dual isotopic composition (δ15N and δ18O) as a tool for exploring sources and cycling of nitrate in an estuarine system: Elkhorn Slough, California

    USGS Publications Warehouse

    Wankel, Scott D.; Kendall, Carol; Paytan, Adina

    2009-01-01

    Nitrate (NO-3 concentrations and dual isotopic composition (??15N and ??18O) were measured during various seasons and tidal conditions in Elkhorn Slough to evaluate mixing of sources of NO-3 within this California estuary. We found the isotopic composition of NO-3 was influenced most heavily by mixing of two primary sources with unique isotopic signatures, a marine (Monterey Bay) and terrestrial agricultural runoff source (Old Salinas River). However, our attempt to use a simple two end-member mixing model to calculate the relative contribution of these two NO-3 sources to the Slough was complicated by periods of nonconservative behavior and/or the presence of additional sources, particularly during the dry season when NO-3 concentrations were low. Although multiple linear regression generally yielded good fits to the observed data, deviations from conservative mixing were still evident. After consideration of potential alternative sources, we concluded that deviations from two end-member mixing were most likely derived from interactions with marsh sediments in regions of the Slough where high rates of NO-3 uptake and nitrification result in NO-3 with low ?? 15N and high ??18O values. A simple steady state dual isotope model is used to illustrate the impact of cycling processes in an estuarine setting which may play a primary role in controlling NO -3 isotopic composition when and where cycling rates and water residence times are high. This work expands our understanding of nitrogen and oxygen isotopes as biogeochemical tools for investigating NO -3 sources and cycling in estuaries, emphasizing the role that cycling processes may play in altering isotopic composition. Copyright 2009 by the American Geophysical Union.

  3. Determining Land System Sustainability through a Land Architecture Approach: Example of Southern Yucatán (Invited)

    NASA Astrophysics Data System (ADS)

    Turner, B. L., II

    2009-12-01

    Sustainable land systems involve an array of tradeoffs, not only among ecosystem services, but between those services and human outcomes. These tradeoffs are affected by the architecture of the land system—the kind, size, pattern, and distribution of land uses and covers. Working towards a model capable of handling a full array of ecosystem services and human outcomes, the concept of land architecture is illustrated through a simplified land system in the seasonal tropical forests of the southern Yucatán where sustainability is sought through the competing goals of forest conservation-preservation and agricultural development, both cultivation and ranching. Land architecture and tradeoff impacts are compared between two communities emphasizing, respectfully, forest conservation-preservation and agriculture. The role of spatial scale is also illustrated. Vulnerability and resilience assessments of land systems should be enhanced through a land architecture approach.

  4. Transpressional segment boundaries in strike-slip fault systems offshore southern California: Implications for fluid expulsion and cold seep habitats

    NASA Astrophysics Data System (ADS)

    Maloney, Jillian M.; Grupe, Benjamin M.; Pasulka, Alexis L.; Dawson, Katherine S.; Case, David H.; Frieder, Christina A.; Levin, Lisa A.; Driscoll, Neal W.

    2015-05-01

    The importance of tectonics and fluid flow in controlling cold seep habitats has long been appreciated at convergent margins but remains poorly understood in strike-slip systems. Here we present geophysical, geochemical, and biological data from an active methane seep offshore from Del Mar, California, in the inner California borderlands (ICB). The location of this seep appears controlled by localized transpression associated with a step in the San Diego Trough fault zone and provides an opportunity to examine the interplay between fluid expulsion and restraining step overs along strike-slip fault systems. These segment boundaries may have important controls on seep locations in the ICB and other margins characterized by strike-slip faulting (e.g., Greece, Sea of Marmara, and Caribbean). The strike-slip fault systems offshore southern California appear to have a limited distribution of seep sites compared to a wider distribution at convergent plate boundaries, which may influence seep habitat diversity and connectivity.

  5. Southern blotting.

    PubMed

    Brown, T

    2001-05-01

    the second alternate protocol is therefore more rapid than the basic protocol and can result in more complete transfer. Although the ease and reliability of capillary transfer methods makes this far and away the most popular system for Southern blotting with agarose gels, it unfortunately does not work with polyacrylamide gels, whose smaller pore size impedes the transverse movement of the DNA molecules. The third alternate protocol describes an electroblotting procedure that is currently the most reliable method for transfer of DNA from a polyacrylamide gel. Dot and slot blotting are also described. PMID:18429082

  6. Epidemiology Analysis of Streptococcus pyogenes in a Hospital in Southern Taiwan by Use of the Updated emm Cluster Typing System

    PubMed Central

    Zheng, Po-Xing; Wang, Shu-Ying; Tsai, Pei-Jane; Chuang, Woei-Jer; Lin, Yee-Shin; Liu, Ching-Chuan

    2015-01-01

    emm typing is the most widely used molecular typing method for the human pathogen Streptococcus pyogenes (group A streptococcus [GAS]). emm typing is based on a small variable region of the emm gene; however, the emm cluster typing system defines GAS types according to the nearly complete sequence of the emm gene. Therefore, emm cluster typing is considered to provide more information regarding the functional and structural properties of M proteins in different emm types of GAS. In the present study, 677 isolates collected between 1994 and 2008 in a hospital in southern Taiwan were analyzed by the emm cluster typing system. emm clusters A-C4, E1, E6, and A-C3 were the most prevalent emm cluster types and accounted for 67.4% of total isolates. emm clusters A-C4 and E1 were associated with noninvasive diseases, whereas E6 was significantly associated with both invasive and noninvasive manifestations. In addition, emm clusters D4, E2, and E3 were significantly associated with invasive manifestations. Furthermore, we found that the functional properties of M protein, including low fibrinogen-binding and high IgG-binding activities, were correlated significantly with invasive manifestations. In summary, the present study provides updated epidemiological information on GAS emm cluster types in southern Taiwan. PMID:26560544

  7. Implications of Nubian-Like Core Reduction Systems in Southern Africa for the Identification of Early Modern Human Dispersals

    PubMed Central

    Phillips, Natasha

    2015-01-01

    Lithic technologies have been used to trace dispersals of early human populations within and beyond Africa. Convergence in lithic systems has the potential to confound such interpretations, implying connections between unrelated groups. Due to their reductive nature, stone artefacts are unusually prone to this chance appearance of similar forms in unrelated populations. Here we present data from the South African Middle Stone Age sites Uitpanskraal 7 and Mertenhof suggesting that Nubian core reduction systems associated with Late Pleistocene populations in North Africa and potentially with early human migrations out of Africa in MIS 5 also occur in southern Africa during early MIS 3 and with no clear connection to the North African occurrence. The timing and spatial distribution of their appearance in southern and northern Africa implies technological convergence, rather than diffusion or dispersal. While lithic technologies can be a critical guide to human population flux, their utility in tracing early human dispersals at large spatial and temporal scales with stone artefact types remains questionable. PMID:26125972

  8. Cultivation-Dependant Assessment, Diversity, and Ecology of Haloalkaliphilic Bacteria in Arid Saline Systems of Southern Tunisia

    PubMed Central

    Guesmi, Amel; Najjari, Afef; Cherif, Hanen; Ettoumi, Besma; Hamdi, Chadlia; Boudabous, Abdellatif

    2013-01-01

    Haloalkaliphiles are polyextremophiles adapted to grow at high salt concentrations and alkaline pH values. In this work, we isolated 122 haloalkaliphilic bacteria upon enrichments of 23 samples from 5 distinct saline systems of southern Tunisia, growing optimally in media with 10% salt and at pH 10. The collection was classified into 44 groups based on the amplification of the 16S–23S rRNA internal transcribed spacers (ITS-PCR). Phylogenetic analysis and sequencing of the 16S rRNA genes allowed the identification of 13 genera and 20 distinct species. Three gram-positive isolates showing between 95 and 96% of 16S rRNA sequence homology with Bacillus saliphilus could represent new species or genus. Beside the difference in bacterial diversity between the studied sites, several species ecological niches correlations were demonstrated such as Oceanobacillus in salt crust, Nesterenkonia in sand, and Salinicoccus in the rhizosphere of the desert plant Salicornia. The collection was further evaluated for the production of extracellular enzymes. Activity tests showed that gram-positive bacteria were mostly active, particularly for protease, lipase, DNase, and amylase production. Our overall results demonstrate the huge phenotypic and phylogenetic diversity of haloalkaliphiles in saline systems of southern Tunisia which represent a valuable source of new lineages and metabolites. PMID:24324969

  9. Active Deformation along the Southern End of the Tosco-Abreojos Fault System: New Insights from Multibeam Swath Bathymetry

    NASA Astrophysics Data System (ADS)

    Michaud, François; Calmus, Thierry; Ratzov, Gueorgui; Royer, Jean-Yves; Sosson, Marc; Bigot-Cormier, Florence; Bandy, William; Mortera Gutiérrez, Carlos

    2011-08-01

    The relative motion of the Pacific plate with respect to the North America plate is partitioned between transcurrent faults located along the western margin of Baja California and transform faults and spreading ridges in the Gulf of California. However, the amount of right lateral offset along the Baja California western margin is still debated. We revisited multibeam swath bathymetry data along the southern end of the Tosco-Abreojos fault system. In this area the depths are less than 1,000 m and allow a finer gridding at 60 m cell spacing. This improved resolution unveils several transcurrent right lateral faults offsetting the seafloor and canyons, which can be used as markers to quantify local offsets. The seafloor of the southern end of the Tosco-Abreojos fault system (south of 24°N) displays NW-SE elongated bathymetric highs and lows, suggesting a transtensional tectonic regime associated with the formation of pull-apart basins. In such an active tectonic context, submarine canyon networks are unstable. Using the deformation rate inferred from kinematic predictions and pull-apart geometry, we suggest a minimum age for the reorganization of the canyon network.

  10. Trophic Dynamics of Filter Feeding Bivalves in the Yangtze Estuarine Intertidal Marsh: Stable Isotope and Fatty Acid Analyses

    PubMed Central

    Wang, Sikai; Jin, Binsong; Qin, Haiming; Sheng, Qiang; Wu, Jihua

    2015-01-01

    Benthic bivalves are important links between primary production and consumers, and are essential intermediates in the flow of energy through estuarine systems. However, information on the diet of filter feeding bivalves in estuarine ecosystems is uncertain, as estuarine waters contain particulate matter from a range of sources and as bivalves are opportunistic feeders. We surveyed bivalves at different distances from the creek mouth at the Yangtze estuarine marsh in winter and summer, and analyzed trophic dynamics using stable isotope (SI) and fatty acid (FA) techniques. Different bivalve species had different spatial distributions in the estuary. Glauconome chinensis mainly occurred in marshes near the creek mouth, while Sinonovacula constricta preferred the creek. Differences were found in the diets of different species. S. constricta consumed more diatoms and bacteria than G. chinensis, while G. chinensis assimilated more macrophyte material. FA markers showed that plants contributed the most (38.86 ± 4.25%) to particular organic matter (POM) in summer, while diatoms contributed the most (12.68 ± 1.17%) during winter. Diatoms made the largest contribution to the diet of S. constricta in both summer (24.73 ± 0.44%) and winter (25.51 ± 0.59%), and plants contributed no more than 4%. This inconsistency indicates seasonal changes in food availability and the active feeding habits of the bivalve. Similar FA profiles for S. constricta indicated that the bivalve had a similar diet composition at different sites, while different δ13C results suggested the diet was derived from different carbon sources (C4 plant Spartina alterniflora and C3 plant Phragmites australis and Scirpus mariqueter) at different sites. Species-specific and temporal and/or spatial variability in bivalve feeding may affect their ecological functions in intertidal marshes, which should be considered in the study of food webs and material flows in estuarine ecosystems. PMID:26261984

  11. Climate change, reproductive performance and diet composition of marine birds in the southern California Current system, 1969 1997

    NASA Astrophysics Data System (ADS)

    Sydeman, William J.; Hester, Michelle M.; Thayer, Julie A.; Gress, Franklin; Martin, Paige; Buffa, Joelle

    We studied the effects of low-frequency climate change on the reproductive performance of 11 species of marine bird in the southern California Current system, 1969-1997. Reproductive performance of Brown Pelican ( Pelecanus occidentalis) and Double-crested Cormorant ( Phalacrocrax auritus) in southern California demonstrated an increase in the 1970s and early 1980s, attributable to recovery from organochlorine contamination (primarily DDE). Brandt's Cormorant ( Phalacrocorax penicillatus) in central California was the only species to demonstrate a secular increase in performance through time, a pattern that remains unexplained. Ashy Storm-petrel ( Oceanodroma homochroa) and Pelagic Cormorant ( Phalacrocorax pelagicus) demonstrated curvilinear patterns of change, with decreasing reproductive performance in the past decade. All other species including Western Gull ( Larus occidentalis), Pigeon Guillemot ( Cepphus columba), Xantus's Murrelet ( Synthiloboramphus hypoleucus), Common Murre ( Uria aalge), Cassin's Auklet ( Ptychoramphus aleuticus) and Rhinoceros Auklet ( Cerorhinca monocerata) showed diminishing reproductive performance through time. Patterns of change for the murre and auklets were not significant, presumably because of a lack of reproductive variation for these species, which display a conservative breeding effort (i.e. single-egg clutches). Changes in the birds' abilities to provision young and maintain chick survival during May-July each year appeared most closely related to overall changes in reproductive performance. Dietary change indicated a decline in use of juvenile rockfish ( Sebastes spp.) by marine birds in central California. There was also significant interannual variability in consumption of juvenile rockfish and the euphausiid Thysanoessa spinifera. Patterns of change in marine bird reproductive performance were generally concordant between southern and central California after considering the period of recovery for Brown Pelican and

  12. The Effect of Ice Shelf Meltwater on Antarctic Sea Ice and the Southern Ocean in an Earth System Model

    NASA Astrophysics Data System (ADS)

    Pauling, A.; Bitz, C. M.; Smith, I.; Langhorne, P.

    2015-12-01

    It has been suggested that recent Antarctic sea ice expansion resulted from an increase in fresh water reaching the Southern Ocean. This presentation investigates this conjecture in an Earth System Model. The freshwater flux from ice sheet and ice shelf mass imbalance is largely missing in models that participated in the Fifth Coupled Model Intercomparison Project (CMIP5). However, CMIP5 models do account for the fresh water from precipitation minus evaporation (P-E). On average in CMIP5 models P- E reaching the Southern Ocean has increased to a present value of about 2600 Gt yr-1 greater than pre-industrial times and 3-8 times larger than estimates of the mass imbalance of Antarctic ice sheets and shelves. Two sets of model experiments were conducted from 1980-2013 in CESM1-CAM5 artificially distributing fresh water either at the ocean surface according to an estimate of iceberg melt, or at the ice shelf fronts at depth. An anomalous reduction in vertical advection of heat into the surface mixed layer resulted in sea surface cooling at high southern latitudes, and an associated increase in sea ice area. A freshwater enhancement of 1780 Gt yr-1 (approximately 1.3 times either present day basal melt or iceberg calving freshwater fluxes) raised the sea ice total area by 1×106 km2. Yet, even a freshwater enhancement up to 2670 Gt yr-1 was insufficient to offset the sea ice decline due to anthropogenic forcing for any period of 20 years or longer. Further, the sea ice response was found to be insensitive to the depth of fresh water injection.

  13. Estuarine acidification and minimum buffer zone—A conceptual study

    NASA Astrophysics Data System (ADS)

    Hu, Xinping; Cai, Wei-Jun

    2013-10-01

    This study uses a simulation method to explore how estuarine pH is affected by mixing between river water, anthropogenic CO2 enriched seawater, and by respiration. Three rivers with different levels of weathering products (Amazon, Mississippi, and St. Johns) are selected for this simulation. The results indicate that estuaries that receive low to moderate levels of weathering products (Amazon and St. Johns) exhibit a maximum pH decrease in the midsalinity region as a result of anthropogenic CO2 intrusion. This maximum pH decrease coincides with a previously unrecognized mid-salinity minimum buffer zone (MBZ). In addition, water column oxygen consumption can further depress pH for all simulated estuaries. We suggest that recognition of the estuarine MBZs may be important for studying estuarine calcifying organisms and pH-sensitive biogeochemical processes.

  14. Predominance of Single Prophage Carrying a CRISPR/cas System in "Candidatus Liberibacter asiaticus" Strains in Southern China.

    PubMed

    Zheng, Zheng; Bao, Minli; Wu, Fengnian; Chen, Jianchi; Deng, Xiaoling

    2016-01-01

    "Candidatus Liberibacter asiaticus" (CLas) is an uncultureable α-proteobacterium associated with citrus Huanglongbing (HLB, yellow shoot disease), a highly destructive disease affecting citrus production worldwide. HLB was observed in Guangdong Province of China over a hundred years ago and remains endemic there. Little is known about CLas biology due to its uncultureable nature. This study began with the genome sequence analysis of CLas Strain A4 from Guangdong in the prophage region. Within the two currently known prophage types, Type 1 (SC1-like) and Type 2 (SC2-like), A4 genome contained only a Type 2 prophage, CGdP2, namely. An analysis on CLas strains collected in Guangdong showed that Type 2 prophage dominated the bacterial population (82.6%, 71/86). An extended survey covering five provinces in southern China also revealed the predominance of single prophage (Type 1 or Type 2) in the CLas population (90.4%, 169/187). CLas strains with two and no prophage types accounted for 7.2% and 2.8%, respectively. In silico analyses on CGdP2 identified a CRISPR (clustered regularly interspaced short palindromic repeats)/cas (CRISPR-associated protein genes) system, consisting of four 22 bp repeats, three 23 bp spacers and 9 predicted cas. Similar CRISPR/cas systems were detected in all 10 published CLas prophages as well as 13 CLas field strains in southern China. Both Type 1 and Type 2 prophages shared almost identical sequences in spacer 1 and 3 but not spacer 2. Considering that the function of a CRISPR/cas system was to destroy invading DNA, it was hypothesized that a pre-established CLas prophage could use its CRISPR/cas system guided by spacer 1 and/or 3 to defeat the invasion of the other phage/prophage. This hypothesis explained the predominance of single prophage type in the CLas population in southern China. This is the first report of CRISPR/cas system in the "Ca. Liberibacter" genera. PMID:26741827

  15. Predominance of Single Prophage Carrying a CRISPR/cas System in “Candidatus Liberibacter asiaticus” Strains in Southern China

    PubMed Central

    Zheng, Zheng; Bao, Minli; Wu, Fengnian; Chen, Jianchi; Deng, Xiaoling

    2016-01-01

    “Candidatus Liberibacter asiaticus” (CLas) is an uncultureable α-proteobacterium associated with citrus Huanglongbing (HLB, yellow shoot disease), a highly destructive disease affecting citrus production worldwide. HLB was observed in Guangdong Province of China over a hundred years ago and remains endemic there. Little is known about CLas biology due to its uncultureable nature. This study began with the genome sequence analysis of CLas Strain A4 from Guangdong in the prophage region. Within the two currently known prophage types, Type 1 (SC1-like) and Type 2 (SC2-like), A4 genome contained only a Type 2 prophage, CGdP2, namely. An analysis on CLas strains collected in Guangdong showed that Type 2 prophage dominated the bacterial population (82.6%, 71/86). An extended survey covering five provinces in southern China also revealed the predominance of single prophage (Type 1 or Type 2) in the CLas population (90.4%, 169/187). CLas strains with two and no prophage types accounted for 7.2% and 2.8%, respectively. In silico analyses on CGdP2 identified a CRISPR (clustered regularly interspaced short palindromic repeats)/cas (CRISPR-associated protein genes) system, consisting of four 22 bp repeats, three 23 bp spacers and 9 predicted cas. Similar CRISPR/cas systems were detected in all 10 published CLas prophages as well as 13 CLas field strains in southern China. Both Type 1 and Type 2 prophages shared almost identical sequences in spacer 1 and 3 but not spacer 2. Considering that the function of a CRISPR/cas system was to destroy invading DNA, it was hypothesized that a pre-established CLas prophage could use its CRISPR/cas system guided by spacer 1 and/or 3 to defeat the invasion of the other phage/prophage. This hypothesis explained the predominance of single prophage type in the CLas population in southern China. This is the first report of CRISPR/cas system in the “Ca. Liberibacter” genera. PMID:26741827

  16. Southern Africa

    Atmospheric Science Data Center

    2013-04-16

    article title:  Southern Africa     View larger JPEG image ... These Multi-angle Imaging SpectroRadiometer (MISR) images of Africa were acquired on August 25, 2000, during Terra orbit 3655. The left ... of smoke plumes and haze. The southern tip of South Africa is at the bottom of the image, and Zambia is at the top. Distinctive ...

  17. Contrasting tropical estuarine ecosystem functioning and stability: A comparative study

    NASA Astrophysics Data System (ADS)

    Villanueva, Maria Ching

    2015-03-01

    A comparative study of the Sine-saloum (Senegal) and Gambia (The Gambia) estuaries was performed based on trophic model outputs that describe the system structure and functioning. These trophic models were constructed such as to differentiate main energetic flows in the systems and express how climate change may have impacted ecosystem resilience to change. Estuarine fish assemblages are highly resilient despite exposure to vast hydrodynamic variations and stress. Coupled with strong anthropogenic-driven stresses such as fisheries and climate change, ecosystems may undergo severe regime shifts that may weaken their resilience and stability. Taxonomically related and morphologically similar species do not necessarily play similar ecological roles in these two ecosystems. Biomass and production in the Sine-saloum are concentrated at trophic levels (TLs) 2 and 3, while for the Gambia, both are concentrated at TL3. Higher TL biomasses in Gambia compared to Sine-Saloum may be explained by the latter ecosystem being characterized by inverse hypersalinity. Higher TL of production in Sine-Saloum is due to higher exploitations compared to Gambia where fishing activities are still less developed. High production and consumption rates of some groups in both ecosystems indicate high system productivity. Elevated productivity may be due to higher abundance of juvenile fishes in most groups that utilize the latter as refuge and/or nursery zones. Both ecosystems are phytoplankton-driven. Differences in group trophic and ecological roles are mainly due to adaptive responses of these species to seasonal and long-term climate and anthropogenic stressors. System indicators suggest different levels of ecosystem resilience and stability as a function of biodiversity. Relevance of other observations on ecosystem functioning and indicators in relation to perturbation is discussed.

  18. Clear Sky Identification Using Data From Remote Sensing Systems at ARM's Southern Great Plains Site

    SciTech Connect

    Delle Monache, L.; Rodriguez, D.; Cederwall, R.

    2000-06-27

    Clouds profoundly affect our weather and climate due, in large part, to their interactions with radiation. Unfortunately, our understanding of these interactions is, at best, incomplete, making it difficult to improve the treatment of atmospheric radiation in climate models. The improved treatment of clouds and radiation, and a better understanding of their interaction, in climate models is one of the Department of Energy's Atmospheric Radiation Measurement (ARM) Program's major goals. To learn more about the distribution of water and ice, i.e., clouds, within an atmospheric column, ARM has chosen to use the remote sensing of clouds, water vapor and aerosols at its three climatologically-diverse sites as its primary observational method. ARM's most heavily instrumented site, which has operated continuously for more than a decade, is its Southern Great Plains (SGP) Central Facility, located near Lamont, OK. Cloud-observing instruments at the Central Facility include the Whole Sky Imager, ceilometers, lidar, millimeter cloud radar, microwave radiometers and radiosondes.

  19. Evaluating the Impact of Solar Generation on Balancing Requirements in Southern Nevada System

    SciTech Connect

    Ma, Jian; Lu, Shuai; Etingov, Pavel V.; Makarov, Yuri V.

    2012-07-26

    Abstract—In this paper, the impacts of solar photovoltaic (PV) generation on balancing requirements including regulation and load following in the Southern Nevada balancing area are analyzed. The methodology is based on the “swinging door” algorithm and a probability box method developed by PNNL. The regulation and load following signals are mimicking the system’s scheduling and real-time dispatch processes. Load, solar PV generation and distributed PV generation (DG) data are used in the simulation. Different levels of solar PV generation and DG penetration profiles are used in the study. Sensitivity of the regulation requirements with respect to real-time solar PV generation forecast errors is analyzed.

  20. Fluid geochemistry of natural manifestations from the Southern Poroto-Rungwe hydrothermal system (Tanzania): Preliminary conceptual model

    NASA Astrophysics Data System (ADS)

    Delalande, Manuëlla; Bergonzini, Laurent; Gherardi, Fabrizio; Guidi, Massimo; Andre, Luc; Abdallah, Issah; Williamson, David

    2011-01-01

    The South Poroto-Rungwe geothermal field, in the northern part of the Malawi rift, Tanzania divides in two main areas. The relatively high altitude northern area around the main Ngozi, Rungwe, Tukuyu and Kyejo volcanoes, is characterised by cold and gas-rich springs. In contrast, hot springs occur in the southern and low-altitude area between the Kyela and Livingstone faults. The isotopic signature of the almost stagnant, cold springs of the Northern district is clearly influenced by H 2O-CO 2(g) exchange as evidenced from negative oxygen-shifts in the order of few deltas permil. In contrast, the isotopic signature of waters discharged from the hot springs of the Southern district is markedly less affected by the H 2O-CO 2(g) interaction. This evidence is interpreted as an effect of the large, permanent outflow of these springs, which supports the hypothesis of a regional-scale recharge of the major thermal springs. Measurements of carbon isotope variations of the dissolved inorganic carbon of waters and CO 2(g) from the Northern and Southern springs support a model of CO 2(g)-driven reactivity all over the investigated area. Our combined chemical and isotopic results show that the composition of hot springs is consistent with a mixing between (i) cold surface fresh (SFW) and (ii) Deep Hot Mineralised (DHMW) Water, indicating that the deep-originated fluids also supply most of the aqueous species dissolved in the surface waters used as local potable water. Based on geothermometric approaches, the temperature of the deep hydrothermal system has been estimated to be higher than 110 °C up to 185 °C, in agreement with the geological and thermal setting of the Malawi rift basin. Geochemical data point to (i) a major upflow zone of geothermal fluids mixed with shallow meteoric waters in the Southern part of the province, and (ii) gas absorption phenomena in the small, perched aquifers of the Northern volcanic highlands.

  1. Carbonatites in a subduction system: The Pleistocene alvikites from Mt. Vulture (southern Italy)

    NASA Astrophysics Data System (ADS)

    D'Orazio, Massimo; Innocenti, Fabrizio; Tonarini, Sonia; Doglioni, Carlo

    2007-10-01

    We report here, for the first time, on the new finding of extrusive calciocarbonatite (alvikite) rocks from the Pleistocene Mt. Vulture volcano (southern Italy). These volcanic rocks, which represent an outstanding occurrence in the wider scenario of the Italian potassic magmatism, form lavas, pyroclastic deposits, and feeder dikes exposed on the northern slope of the volcano. The petrography, mineralogy and whole-rock chemistry attest the genuine carbonatitic nature of these rocks, that are characterized by high to very high contents of Sr, Ba, U, LREE, Nb, P, F, Th, high Nb/Ta and LREE/HREE ratios, and low contents of Ti, Zr, K, Rb, Na and Cs. The O-C isotope compositions are close to the "primary igneous carbonatite" field and, thus, are compatible with an ultimate mantle origin for these rocks. The Sr-Nd-Pb-B isotope compositions, measured both in the alvikites and in the silicate volcanic rocks, indicate a close genetic relationship between the alvikites and the associated melilitite/nephelinite rocks. Furthermore, these latter products are geochemically distinct from the main foiditic-phonolitic association of Mt. Vulture. We propose a petrogenetic/geodynamic interpretation which has important implications for understanding the relationships between carbonatites and orogenic activity. In particular, we propose that the studied alvikites are generated through liquid unmixing at crustal levels, starting from nephelinitic or melilititic parent liquids. These latter were produced in a hybrid mantle resulting from the interaction through a vertical slab window, between a metasomatized mantle wedge, moving eastward from the Tyrrhenian/Campanian region, and the local Adriatic mantle. The occurrence of carbonatite rocks at Mt. Vulture, that lies on the leading edge of the Southern Apennines accretionary prism, is taken as an evidence for the carbonatation of the mantle sources of this volcano. We speculate that mantle carbonatation is related to the introduction of

  2. Biogeochemical classification of South Florida's estuarine and coastal waters.

    PubMed

    Briceño, Henry O; Boyer, Joseph N; Castro, Joffre; Harlem, Peter

    2013-10-15

    South Florida's watersheds have endured a century of urban and agricultural development and disruption of their hydrology. Spatial characterization of South Florida's estuarine and coastal waters is important to Everglades' restoration programs. We applied Factor Analysis and Hierarchical Clustering of water quality data in tandem to characterize and spatially subdivide South Florida's coastal and estuarine waters. Segmentation rendered forty-four biogeochemically distinct water bodies whose spatial distribution is closely linked to geomorphology, circulation, benthic community pattern, and to water management. This segmentation has been adopted with minor changes by federal and state environmental agencies to derive numeric nutrient criteria. PMID:23968989

  3. Skills of yearly prediction of the early-season rainfall over southern China by the NCEP climate forecast system

    NASA Astrophysics Data System (ADS)

    Zhao, Siyu; Yang, Song; Deng, Yi; Li, Qiaoping

    2015-11-01

    The prominent rainfall over southern China from April to June, usually characterized by a rain belt aligned in a southwest-northeast direction, is referred to here as the early-season rainfall (ESR). The predictability of the ESR is studied by analyzing the 45-day hindcast made with the US National Centers for Environmental Prediction Climate Forecast System version 2 (CFSv2) and several observational data sets. Skills of predicting the ESR and the associated atmospheric circulation and surface air temperature (SAT) patterns in each year are assessed with multiple methods. Results show that the ESR can be well predicted by the CFSv2 in advance by 20 days in some years including 2005 and 2006, while the lead time of skillful prediction is limited to around 1 week in some other years such as 2001 and 2010. More accurate predictions of the ESR seem to be related to the higher skills of CFSv2 in predicting the dominant modes of the rainfall variability. Moreover, atmospheric circulation patterns associated with the ESR and the SAT over the western Pacific warm pool in the preceding winter can be important signals for ESR prediction since in the years with good skills of ESR prediction, the CFSv2 also predicted these signals successfully. An overestimate (underestimate) of the SAT may lead to large biases in the predicted atmospheric circulation and subsequently result in an underestimate (overestimate) southern China ESR.

  4. Controls on monthly estuarine residuals: Eulerian circulation and elevation

    NASA Astrophysics Data System (ADS)

    Brown, Jennifer M.; Bolaños, Rodolfo; Souza, Alejandro J.

    2014-04-01

    The Dee Estuary, at the NW English-Welsh border, is a major asset, supporting: one of the largest wildlife habitats in Europe, industrial importance along the Welsh coastline and residential and recreational usage along the English coast. Understanding of the residual elevation is important to determine the total water levels that inundate intertidal banks, especially during storms. Whereas, improved knowledge of the 3D residual circulation is important in determining particle transport pathways to manage water quality and morphological change. Using mooring data obtained in February-March 2008, a 3D modelling system has been previously validated against in situ salinity, velocity, elevation and wave observations, to investigate the barotropic-baroclinic wave interaction within this estuary under full realistic forcing. The system consists of a coupled circulation-wave-turbulence model (POLCOMS-WAM-GOTM). Using this modelling system the contribution of different processes and their interactions to the monthly residuals in both elevation and circulation is now assessed. By studying a tidally dominated estuary under wave influence, it is found that baroclinicity induced by a weak river flow has greater importance in generating a residual circulation than the waves, even at the estuary mouth. Although the monthly residual circulation is dominated by tidal and baroclinic processes, the residual estuarine surface elevation is primarily influenced by the seasonal external forcing to the region, with secondary influence from the local wind conditions. During storm conditions, 3D radiation stress becomes important for both elevation and circulation at the event scale but is found here to have little impact over monthly time scales.

  5. Southern Crater

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Context image for PIA03583 Southern Crater

    This crater is located south of Agassiz Crater. It is likely that the polar freeze/thaw/frost cycle is responsible for unusual appearance of the ejecta region around the crater.

    Image information: VIS instrument. Latitude 76.2S, Longitude 247.8E. 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  6. The solar neighborhood. XXXV. Distances to 1404 M dwarf systems within 25 PC in the southern sky

    SciTech Connect

    Winters, Jennifer G.; Jao, Wei-Chun; Dieterich, Sergio B. E-mail: jao@astro.gsu.edu; and others

    2015-01-01

    We present trigonometric, photometric, and photographic distances to 1748 southern (δ⩽0{sup ∘}) M dwarf systems with μ⩾0{sub ⋅}{sup ′′}18 yr{sup −1}, of which 1404 are believed to lie within 25 pc of the Sun. The stars have 6.67⩽V{sub J}⩽21.38 and 3.50⩽(V{sub J}−K{sub s})⩽9.27, covering the entire M dwarf spectral sequence from M0.0 V through M9.5 V. This sample therefore provides a comprehensive snapshot of our current knowledge of the southern sky for the nearest M dwarfs that dominate the stellar population of the Galaxy. Roughly one-third of the 1748 systems, each of which has an M dwarf primary, have published high quality parallaxes, including 179 from the REsearch Consortium On Nearby Stars astrometry program. For the remaining systems, we offer photometric distance estimates that have well-calibrated errors. The bulk of these (∼700) are based on new V{sub J}R{sub KC}I{sub KC} photometry acquired at the CTIO/SMARTS 0.9 m telescope, while the remaining 500 primaries have photographic plate distance estimates calculated using SuperCOSMOS B{sub J}R{sub 59F}I{sub IVN} photometry. Confirmed and candidate subdwarfs in the sample have been identified, and a census of companions is included.

  7. Towards a coastal ocean forecasting system in Southern Adriatic Northern Ionian seas based on unstructured-grid model

    NASA Astrophysics Data System (ADS)

    Federico, Ivan; Oddo, Paolo; Pinardi, Nadia; Coppini, Giovanni

    2014-05-01

    The Southern Adriatic Northern Ionian Forecasting System (SANIFS) operational chain is based on a nesting approach. The large scale model for the entire Mediterranean basin (MFS, Mediterranean Forecasting system, operated by INGV, e.g. Tonani et al. 2008, Oddo et al. 2009) provides lateral open boundary conditions to the regional model for Adriatic and Ionian seas (AIFS, Adriatic Ionian Forecasting System) which provides the open-sea fields (initial conditions and lateral open boundary conditions) to SANIFS. The latter, here presented, is a coastal ocean model based on SHYFEM (Shallow HYdrodynamics Finite Element Model) code, which is an unstructured grid, finite element three-dimensional hydrodynamic model (e.g. Umgiesser et al., 2004, Ferrarin et al., 2013). The SANIFS hydrodynamic model component has been designed to provide accurate information of hydrodynamics and active tracer fields in the coastal waters of Southern Eastern Italy (Apulia, Basilicata and Calabria regions), where the model is characterized by a resolution of about of 200-500 m. The horizontal resolution is also accurate in open-sea areas, where the elements size is approximately 3 km. During the development phase the model has been initialized and forced at the lateral open boundaries through a full nesting strategy directly with the MFS fields. The heat fluxes has been computed by bulk formulae using as input data the operational analyses of European Centre for Medium-Range Weather Forecasts. Short range pre-operational forecast tests have been performed in different seasons to evaluate the robustness of the implemented model in different oceanographic conditions. Model results are validated by means of comparison with MFS operational results and observations. The model is able to reproduce the large-scale oceanographic structures of the area (keeping similar structures of MFS in open sea), while in the coastal area significant improvements in terms of reproduced structures and dynamics are

  8. The Asian-Australian monsoon and El Nino-Southern Oscillation in the NCAR Climate System Model

    SciTech Connect

    Meehl, G.A.; Arblaster, J.M.

    1998-06-01

    Features associated with the Asian-Australian monsoon system and El Nino-Southern Oscillation (ENSO) are described in the National Center for Atmospheric Research (NCAR) global coupled Climate System Model (CSM). Simulation characteristics are compared with a version of the atmospheric component of the CSM, the NCAR CCM3, run with time-evolving SSTs from 1950 to 1994, and with observations. The CSM is shown to represent most major features of the monsoon system in terms of mean climatology, interannual variability, and connections to the tropical Pacific. This includes a representation of the Southern Oscillation links between strong Asian-Australian monsoons and associated negative SST anomalies in the eastern equatorial Pacific. The equatorial SST gradient across the Pacific in the CSM is shown to be similar to the observed with somewhat cooler mean SSTs across the entire Pacific by about 1--2 C. The seasonal cycle of SSTs in the eastern equatorial Pacific has the characteristic signature seen in the observations of relatively warmer SSTs propagating westward in the first half of the year followed by the reestablishment of the cold tongue with relatively colder SSTs propagating westward in the second half of the year. Like other global coupled models, the propagation is similar to the observed but with the establishment of the relatively warmer water in the first half of the year occurring about 1--2 months later than observed. The seasonal cycle of precipitation in the tropical eastern Pacific is also similar to other global coupled models in that there is a tendency for a stronger-than-observed double ITCZ year round, particularly in northern spring, but with a well-reproduced annual maximum of ITCZ strength north of the equator in the second half of the year.

  9. Health systems and access to antiretroviral drugs for HIV in Southern Africa: service delivery and human resources challenges.

    PubMed

    Schneider, Helen; Blaauw, Duane; Gilson, Lucy; Chabikuli, Nzapfurundi; Goudge, Jane

    2006-05-01

    Without strengthened health systems, significant access to antiretroviral (ARV) therapy in many developing countries is unlikely to be achieved. This paper reflects on systemic challenges to scaling up ARV access in countries with both massive epidemics and weak health systems. It draws on the authors' experience in southern Africa and the World Health Organization's framework on health system performance. Whilst acknowledging the still significant gap in financing, the paper focuses on the challenges of reorienting service delivery towards chronic disease care and the human resource crisis in health systems. Inadequate supply, poor distribution, low remuneration and accelerated migration of skilled health workers are increasingly regarded as key systems constraints to scaling up of HIV treatment. Problems, however, go beyond the issue of numbers to include productivity and cultures of service delivery. As more countries receive funds for antiretroviral access programmes, strong national stewardship of these programmes becomes increasingly necessary. The paper proposes a set of short- and long-term stewardship tasks, which include resisting the verticalisation of HIV treatment, the evaluation of community health workers and their potential role in HIV treatment access, international action on the brain drain, and greater investment in national human resource functions of planning, production, remuneration and management. PMID:16713875

  10. Aseismic Slip Events along the Southern San Andreas Fault System Captured by Radar Interferometry

    SciTech Connect

    Vincent, P

    2001-10-01

    A seismic slip is observed along several faults in the Salton Sea and southernmost Landers rupture zone regions using interferometric synthetic aperture radar (InSAR) data spanning different time periods between 1992 and 1997. In the southernmost Landers rupture zone, projecting south from the Pinto Mountain Fault, sharp discontinuities in the interferometric phase are observed along the sub-parallel Burnt Mountain and Eureka Peak Faults beginning three months after the Landers earthquake and is interpreted to be post-Landers after-slip. Abrupt phase offsets are also seen along the two southernmost contiguous 11 km Durmid Hill and North Shore segments of the San Andreas Fault with an abrupt termination of slip near the northern end of the North Shore Segment. A sharp phase offset is seen across 20 km of the 30 km-long Superstition Hills Fault before phase decorrelation in the Imperial Valley along the southern 10 km of the fault prevents coherent imaging by InSAR. A time series of deformation interferograms suggest most of this slip occurred between 1993 and 1995 and none of it occurred between 1992 and 1993. A phase offset is also seen along a 5 km central segment of the Coyote Creek fault that forms a wedge with an adjoining northeast-southwest trending conjugate fault. Most of the slip observed on the southern San Andreas and Superstition Hills Faults occurred between 1993 and 1995--no slip is observed in the 92-93 interferograms. These slip events, especially the Burnt Mountain and Eureka Peak events, are inferred to be related to stress redistribution from the June, 1992 M{sub w} = 7.3 Landers earthquake. Best-fit elastic models of the San Andreas and Superstition Hills slip events suggest source mechanisms with seismic moments over three orders of magnitude larger than a maximum possible summation of seismic moments from all seismicity along each fault segment during the entire 4.8-year time interval spanned by the InSAR data. Aseismic moment releases of this

  11. Tungsten-molybdenum fractionation in estuarine environments

    NASA Astrophysics Data System (ADS)

    Mohajerin, T. Jade; Helz, George R.; Johannesson, Karen H.

    2016-03-01

    Dissolved tungsten (W) and molybdenum (Mo) concentrations were measured in surface waters and sediment pore waters of Terrebonne Bay, a shallow estuary in the Mississippi River delta, to investigate the biogeochemical processes that fractionate these Group 6 elements relative to one another during transit from weathering to sedimentary environments. Although many of the chemical properties of W and Mo are similar, the two elements behave autonomously, and the fractionation mechanisms are only partly understood. In sulfidic pore waters, dissolved Mo is depleted relative to river water-seawater mixtures, whereas dissolved W is >10-fold enriched. Reductive dissolution of poorly crystalline phases like ferrihydrite, which is a preferential host of W relative to Mo in grain coatings on river-borne particles, can explain the dissolved W enrichment. Dissolved W becomes increasingly enriched as H2S(aq) rises above about 60 μM due to transformation of WO42- to thiotungstates as well as to additional reductive dissolution of phases that host W. In contrast, as rising sulfide transforms MoO42- to thiomolybdates in pore waters, dissolved Mo is suppressed, probably owing to equilibration with an Fe-Mo-S phase. This putative phase appears to control the aqueous ion product, Q = [Fe2+][MoS42-]0.6 [H2S0]0.4/[H+]0.8, at a value of 10-7.78. Concentrations of dissolved W and Mo in pore waters bear no relation to concentrations in surface waters of the same salinity. In surface waters, dissolved Mo is nearly conserved in the estuarine mixing zone. Dissolved W appears also to be conserved except for several cases where W may have been enhanced by exchange with underlying, W-rich pore waters. With increasing salinity, the molar Mo/W ratio rises from about 10 to about 1000 in surface waters whereas it is mostly <10 in underlying pore waters and in highly sulfidic pore waters is mostly near 1. Differences in two chemical properties may account for this fractionation of Mo with respect to

  12. Systemic toxoplasmosis and Gram-negative sepsis in a southern chamois (Rupicapra pyrenaica) from the Pyrenees in northeast Spain.

    PubMed

    Marco, Ignasi; Velarde, Roser; López-Olvera, Jorge R; Cabezón, Oscar; Pumarola, Martí; Lavín, Santiago

    2009-03-01

    A 6-year-old, male southern chamois (Rupicapra pyrenaica) had an absence of flight response and was captured by hand in the Catalan Pyrenees in northeast Spain. On clinical examination, the animal was in good body condition, and only atrophy of the right eye was observed. Blood samples were collected and hematologic analysis performed, but no alterations were observed. The animal was sent to a Wildlife Rescue Centre, where it developed chronic wasting and died after 32 days in captivity. At necropsy, the animal was cachectic and had edematous, mottled lungs. Histopathologic examination revealed systemic toxoplasmosis and acute Gram-negative septicemia. The protozoan organisms were identified as Toxoplasma gondii based on immunohistochemistry. An indirect fluorescent antibody test was performed, and the animal was positive with an antibody titer of 150. PMID:19286506

  13. A continuous, real-time water quality monitoring system for the coral reef ecosystems of Nanwan Bay, Southern Taiwan.

    PubMed

    Tew, Kwee Siong; Leu, Ming-Yih; Wang, Jih-Terng; Chang, Chia-Ming; Chen, Chung-Chi; Meng, Pei-Jie

    2014-08-30

    The coral reef ecosystems of Nanwan Bay, Southern Taiwan are undergoing degradation due to anthropogenic impacts, and as such have resulted in a decline in coral cover. As a first step in preventing the continual degradation of these coral reef environments, it is important to understand how changes in water quality affect these ecosystems on a fine-tuned timescale. To this end, a real-time water quality monitoring system was implemented in Nanwan Bay in 2010. We found that natural events, such as cold water intrusion due to upwelling, tended to elicit temporal shifts in coral spawning between 2010 and 2011. In addition, Degree Heating Weeks (DHWs), a commonly utilized predictor of coral bleaching, were 0.92 and 0.59 in summer 2010 and 2011, respectively. Though this quantity of DHW was below the presumed stress-inducing value for these reefs, a rise in DHWs in the future may stress the resident corals. PMID:24332988

  14. Decoupling of nutrient and grazer impacts on a benthic estuarine diatom assemblage

    PubMed Central

    Armitage, Anna R.; Gonzalez, Vanessa L.; Fong, Peggy

    2014-01-01

    Strong interactions between top-down (consumptive) and bottom-up (resource supply) trophic factors occur in many aquatic communities, but these forces can act independently in some microphytobenthic communities. Within benthic estuarine diatom assemblages, the dynamics of these interactions and how they vary with abiotic environmental conditions are not well understood. We conducted a field experiment at two sites with varying habitat characteristics to investigate the interactive effects of grazers and nutrients on benthic estuarine diatoms. We crossed snail (Cerithidea californica) and nutrient (nitrogen and phosphorus) addition treatments in enclosures on a restored tidal sandflat and a reference tidal mudflat in Mugu Lagoon, southern California. We repeated the study in summer 2000 and spring 2001 to assess temporal variation in the interactions. Snails caused a large decrease in diatom relative abundance and biomass (estimated as surface area); nutrients increased diatom abundance but did not alter diatom biomass. Snails and nutrients both reduced average diatom length, although the nutrient effect was weaker and temporally variable, occurring in the reference mudflat in the spring. There were few interactions between snail and nutrient addition treatments, suggesting that links between top-down and bottom-up forces on the diatom community were weak. There were no consistent differences in diatom assemblage characteristics between the two study sites, despite marked differences in sediment grain size and other abiotic characteristics between the sites. The strong diatom response to herbivores and weaker responses to enrichment differed from the previous studies where cyanobacteria increased in response to nutrient enrichment, further dissolving the “black box” perception of microphytobenthic communities. PMID:25568503

  15. Occurrence of nitrate, pesticides, and volatile organic compounds in the Kirkwood-Cohansey aquifer system, southern New Jersey

    USGS Publications Warehouse

    Stackelberg, Paul E.; Hopple, Jessica A.; Kauffman, Leon J.

    1997-01-01

    Water samples were collected from a network of 72 shallow monitoring wells to assess the chemical quality of recently recharged ground water in the surficial Kirkwood- Cohansey aquifer system of southern New Jersey. The wells are randomly distributed among agricultural, urban, and undeveloped areas to provide data representative of chemical conditions of ground water underlying each of these land-use settings. Samples were analyzed for nutrients, pesticides, and volatile organic compounds (VOC?s). Concentrations of nitrate were highest in agricultural areas, where the U.S. Environmental Protection Agency (USEPA) Maximum Contaminant Level (MCL) of 10 mg/L (milligrams per liter) as nitrogen was exceeded in 60 percent of the samples. Concentrations of nitrate were intermediate in urban areas, where the 10-mg/L concentration was exceeded in only 1 of 44 samples. All concentrations in samples from undeveloped areas were less than 1.0 mg/L. Pesticides and VOC?s were frequently detected; however, concentrations were low and rarely exceeded established or proposed USEPA or N.J. Department of Environmental Protection (NJDEP) drinking-water regulations. With the exception of the agricultural pesticide dinoseb, established regulations are at least 2.9 times the maximum concentration for pesticides and at least 5 times the maximum concentration for VOC?s reported in the samples from the 72- well network. Investigations by the U.S. Geological Survey (USGS) are ongoing in southern New Jersey to evaluate the (1) presence and concentration of pesticide-degradation byproducts in shallow ground water; (2) presence and movement of nitrate, pesticides, and VOC?s in the atmosphere, streams, unsaturated zone, and aquifers; (3) transport and fate of these compounds as they migrate deeper into the aquifer system; and (4) implications of these findings for the integrity of the regional water supply.

  16. Southern Rains

    Atmospheric Science Data Center

    2014-05-15

    ...   View Larger image Vigorous vegetation growth in the Southern United States after heavy rains fell during April and ... for atmospheric scattering and absorption effects, and use plant canopy structural models to determine the partitioning of solar ...

  17. EFFECTS OF SEVIN ON DEVELOPMENT OF EXPERIMENTAL ESTUARINE COMMUNITIES

    EPA Science Inventory

    The composition of animal communities developing from planktonic larvae in aquariums containing sand and flowing estuarine water was altered in the presence of the carbamate insecticide Sevin (carbaryl). Treatments were control and concentrations of Sevin that averaged 1.1, 11.1,...

  18. HALOCARBON PRODUCTION FROM OXIDATIVE BIOCIDES IN ESTUARINE WATERS

    EPA Science Inventory

    The formation of halo-organic compounds by chlorination of estuarine waters has been investigated under both laboratory and field conditions. Haloforms are readily generated in the laboratory with chlorine doses of 1 to 10 mg/l, the range employed by many coastal power plants. At...

  19. IMPACT OF UV-B RADIATION UPON ESTUARINE MICROCOSMS

    EPA Science Inventory

    Twelve flow-through estuarine microcosms were exposed daily to four different levels of UV-B radiation. In addition to a natural level of visible solar radiation. The parameters studied over a four week period were phytoplankton community composition, plankton biomass (ash-free d...

  20. RESPONSES OF DEVELOPING ESTUARINE MACROBENTHIC COMMUNITIES TO DRILLING MUDS

    EPA Science Inventory

    The effects of drilling mud, used in oil drilling operations, on development of estuarine macrobenthic communities from settling planktonic larvae were assessed by comparing numbers and species of animals that grew in uncontaminated and contaminated aquaria for 8 weeks. Aquaria c...

  1. Ordination of the estuarine environment: What the organism experiences

    EPA Science Inventory

    Investigators customarily schedule estuary sampling trips with regard to a variety of criteria, especially tide stage and the day-night cycle. However, estuarine organisms experience a wide suite of continuously changing tide and light conditions. Such organisms may undertake i...

  2. Monitoring nekton as a bioindicator in shallow estuarine habitats

    USGS Publications Warehouse

    Raposa, K.B.; Roman, C.T.; Heltshe, J.F.

    2003-01-01

    Long-term monitoring of estuarine nekton has many practical and ecological benefits but efforts are hampered by a lack of standardized sampling procedures. This study provides a rationale for monitoring nekton in shallow (< 1 m), temperate, estuarine habitats and addresses some important issues that arise when developing monitoring protocols. Sampling in seagrass and salt marsh habitats is emphasized due to the susceptibility of each habitat to anthropogenic stress and to the abundant and rich nekton assemblages that each habitat supports. Extensive sampling with quantitative enclosure traps that estimate nekton density is suggested. These gears have a high capture efficiency in most habitats and are small enough (e.g., 1 m(2)) to permit sampling in specific microhabitats. Other aspects of nekton monitoring are discussed, including spatial and temporal sampling considerations, station selection, sample size estimation, and data collection and analysis. Developing and initiating long-term nekton monitoring programs will help evaluate natural and human-induced changes in estuarine nekton over time and advance our understanding of the interactions between nekton and the dynamic estuarine environment.

  3. EFFECTS OF HALOGENATED ORGANIC COMPOUNDS ON PHOTOSYNTHESIS IN ESTUARINE PHYTOPLANKTON

    EPA Science Inventory

    Chlorine oxidants (chlorine gas, sodium hypochlorite, and calcium hypochlorite) are used as biocides to control fouling in seawater cooled power generating plants and to kill pathogens in sewage effluents entering estuarine waters. The effects of chlorinated by-products on estuar...

  4. UPTAKE AND TOXICITY OF TOXAPHENE IN SEVERAL ESTUARINE ORGANISMS

    EPA Science Inventory

    The organochlorine insecticide, toxaphene, was tested in flow-through bioassays to evaluate its toxicity to estuarine organisms. The organisms tested and their respective 96-hr LC50s (based on measured concentrations) are: pink shrimp (Penaeus duorarum), 1.4 micrograms/L; grass s...

  5. ACUTE TOXICITY AND BIOCONCENTRATION OF ENDOSULFAN-EXPOSED ESTUARINE ANIMALS

    EPA Science Inventory

    Acute (96-h) flow-through toxicity tests with endosulfan (Thiodan) were conducted with several estuarine animals. The test species and their 96-h lethal concentration for 50 percent of the organisms (LC50) values were: pink shrimp (Penaeus duorarum), 0.04 micrograms/litre; grass ...

  6. CADMIUM TOXICITY TO THREE SPECIES OF ESTUARINE INVERTEBRATES

    EPA Science Inventory

    Three species of estuarine invertebrates, Palaemonetes pugio (grass shrimp), Pagurus longicarpus (hermit crab) and Argopecten irradians (bay scallop), were exposed to Cd in flowing seawater at concentrations of 0.06, 0.12, 0.25, 0.5 and 1.0 mg/litre. Incipient LC50 values of 0.53...

  7. Field Study Manual to Freshwater and Estuarine Habitats.

    ERIC Educational Resources Information Center

    Georgia State Dept. of Education, Atlanta.

    This field studies manual, developed by biology students in the 1971 Georgia Governor's Honors Program, was designed for collection of data pertinent to freshwater and estuarine habitats. In addition to the various methods of sampling the ecosystem and for quantification of the data, instructions for dividing the field study into three logical…

  8. Marine and Estuarine Ecology. Man and the Gulf of Mexico.

    ERIC Educational Resources Information Center

    Irby, Bobby N.; And Others

    "Man and the Gulf of Mexico (MGM)" is a marine science curriculum developed to meet the marine science needs of tenth through twelfth grade students in Mississippi and Alabama schools. This MGM unit, which focuses on marine and estuarine ecology, is divided into six sections. The first section contains unit objectives, discussions of the estuarine…

  9. DISTRIBUTION OF MIREX IN AN EXPERIMENTAL ESTUARINE ECOSYSTEM

    EPA Science Inventory

    Distribution of mirex in various compartments of an experimental estuarine ecosystem was determined. Uptake occurred from mirex concentrations in the water that averaged 0.061 plus or minus 0.031 micrograms/liter. Accumulation occurred to the highest degree in the hepato-pancreas...

  10. Salt Marsh--Estuarine Ecosystem: A Liquid Asset

    ERIC Educational Resources Information Center

    Steever, E. Zell

    1977-01-01

    A comprehensive description of the salt marsh-estuarine ecosystem is provided. Topics discussed include: the general geologic history and formation of this ecosystem; physical and chemical parameters; variety; primary productivity; tidal zones; kind, sizes and abundance of vegetation; and the environmental factors influencing vegetation. (BT)

  11. Seismic properties of the Nazca oceanic crust in southern Peruvian subduction system

    NASA Astrophysics Data System (ADS)

    Kim, YoungHee; Clayton, Robert W.

    2015-11-01

    The horizontal Nazca slab, extending over a distance of ∼800 km along the trench is one of enigmatic features in Peruvian subduction zone. Increased buoyancy of the oceanic lithosphere alone due to the subduction of Nazca Ridge is insufficient to fully explain such a lengthy segment. We use data from the recent seismic experiment in southern Peru to find that the subduction-related hydration plays a major role in controlling shear wave velocities within the upper part of the oceanic crust and overlying materials. We observe substantial velocity reductions of ∼20-40% near the top plate interface along- and perpendicular-to the trench from ∼40-120 km depths. In particular, significant shear wave velocity reductions and subsequently higher P-to-S velocity ratio (exceeding 2.0) at the flat slab region suggest that the seismically probed layer is fluid-rich and mechanically weak. The dominant source of fluid comes from metasediments and subducted crust (Nazca Ridge). Long-term supply of fluid from the southward migrating Nazca Ridge provides additional buoyancy of the subducting oceanic lithosphere and also lowers the viscosity of the overlying mantle wedge to drive and sustain the flat plate segment of ∼800 km along the trench. Also, by comparing calculated seismic velocities with experimentally derived mineral physics data, we additionally provide mechanical constraints on the possible changes in frictional behavior across the subduction zone plate interface. Observed low seismic velocities in the seismogenic zone suggest a presence of low strength materials that may be explained by overpressured pore fluids (i.e., accreted sediment included in the subduction channel).

  12. Groundwater availability in the shallow aquifers of the southern voltaian system: a simulation and chemical analysis

    NASA Astrophysics Data System (ADS)

    Yidana, Sandow; Ophori, Duke; Banoeng-Yakubo, Bruce

    2008-10-01

    A steady state groundwater flow simulation model was developed using available well data and general hydrogeological and geological information, for the Afram Plains area, Ghana. The hydrochemistry of groundwater from wells in the area was then evaluated to determine its suitability for irrigation and domestic uses. The assessment of the irrigation quality of groundwater from this area was based on salinity (EC) and sodium adsorption ratios (SAR), residual sodium carbonate (RSC), and permeability indices (PI). The simulation model reveals that groundwater in the Afram Plains area generally flows from the midsections in the neighborhood of Tease and surrounding areas, where significant recharge takes place, to the outer regions and discharges into the Volta Lake in the southern and eastern sections of the area. Flow magnitude and piezometric maps suggest that there is probably of less potential for groundwater extraction for sustainable irrigation in the central regions of the area, when compared to the other discharge areas. This study reveals that more than 70% of the samples analyzed fall within the C2 S1 category, referring to the medium level salinity and low sodium. Medium salinity waters may be used for irrigation on coarse textured soils with good permeability. About 15% of the data fall within the C3 S2 category, referring to water of high salinity and medium sodicity. High salinity, medium sodicity irrigation water cannot be used on fine-grained soils where drainage is restricted. This is because restricted flow is likely to result in the accumulation of salts in the root zones of crops, leading to salinity and soil clogging crisis. About 3% falls within the C3 S3 (high salinity, high sodicity) category. This category requires special soil management including improved drainage, heavy leaching and the use of chemical amendments on the water. Only one point plots within the extreme salinity sodicity range. Concentrations of fluoride, arsenic and other

  13. Juvenile fish condition in estuarine nurseries along the Portuguese coast

    NASA Astrophysics Data System (ADS)

    Vasconcelos, R. P.; Reis-Santos, P.; Fonseca, V.; Ruano, M.; Tanner, S.; Costa, M. J.; Cabral, H. N.

    2009-03-01

    Connectivity between estuarine fish nurseries and coastal adult habitats can be affected by variations in juvenile growth and survival. Condition indices are renowned proxies of juvenile nutritional status and growth rates and are valuable tools to assess habitat quality. Biochemical (RNA:DNA ratio) and morphometric (Fulton's condition factor K) condition indices were determined in juveniles of Solea solea, Solea senegalensis, Platichthys flesus, Diplodus vulgaris and Dicentrarchus labrax collected in putative nursery areas of nine estuaries along the Portuguese coast (Minho, Douro, Ria de Aveiro, Mondego, Tejo, Sado, Mira, Ria Formosa and Guadiana) in the Spring and Summer of two consecutive years (2005 and 2006) with distinct climatic characteristics. Individual condition showed significant variation amongst species. The combined use of both condition indices highlighted the low correlation between them and that RNA:DNA had a higher sensitivity. RNA:DNA varied between years but overall the site relative patterns in condition were maintained from one year to the other. Higher RNA:DNA values were found in Spring than in Summer in most species. Intra-estuarine variation also occurred in several cases. Species specific trends in the variability of condition amongst estuaries were highlighted. Some estuaries had higher juvenile condition for more than one species but results did not reveal an identical trend for all species and sites, hindering the hypotheses of one estuarine nursery promoting superior growth for all present species. Significant correlations were found between condition indices, juvenile densities and environmental variables (water temperature, salinity and depth) in the estuarine nurseries. These influenced juvenile nutritional condition and growth, contributing to the variability in estuarine nursery habitat quality. Management and conservation wise, interest in multi-species approaches is reinforced as assessments based on a single species may not

  14. A Linked Physical and Biological Framework to Assess Biogeochemical Dynamics in a Shallow Estuarine Ecosystem

    NASA Astrophysics Data System (ADS)

    Buzzelli, C. P.; Wetzel, R. L.; Meyers, M. B.

    1999-12-01

    The littoral zone of Chesapeake Bay contains a mosaic of shallow vegetated and nonvegetated habitats with biotic components that are sensitive to changes in biological and physical driving factors. Static and dynamic modelling frameworks provide an integrative way to study complex hydrodynamic and biogeochemical processes in linked estuarine habitats. In this study we describe a spatial simulation model developed and calibrated relative to a specific littoral zone, estuarine ecosystem. The model consisted of four distinct habitats that contained phytoplankton, sediment microalgae, Zostera marina (eelgrass), and Spartina alterniflora. There was tidal exchange of phytoplankton, particulate and dissolved organic carbon and dissolved inorganic nitrogen between the littoral zone ecosystem and the offshore channel. Physical exchange and biogeochemical transformations within the habitats determined water column concentrations in each habitat. Predicted subtidal water column concentrations and Z. marina and S. alterniflora biomass were within the variability of validation data and the predicted annual rates of net primary production were similar to measured rates. Phytoplankton accounted for 17%, sediment microalgae 46%, the Z. marina community 24% and S. alterniflora 13% of the annual littoral zone primary production. The linked habitat model provided insights into producer, habitat and ecosystem carbon and nitrogen properties that might not have been evident with stand-alone models. Although it was an intra-ecosystem sink for particulate carbon, the seagrass habitat was a DOC source and responsible for over 30% of the littoral zone carbon and nitrogen primary production. The model predicted that the Goodwin Islands littoral zone was a sink of channel derived POC, but a source of DOC to the surrounding estuary. The framework created in this study of estuarine ecosystem dynamics is applicable to many different aquatic systems over a range of spatial and temporal scales.

  15. Responses of estuarine circulation and salinity to the loss of intertidal flats – A modeling study

    SciTech Connect

    Yang, Zhaoqing; Wang, Taiping

    2015-08-25

    Intertidal flats in estuaries are coastal wetlands that provide critical marine habitats to support wide ranges of marine species. Over the last century many estuarine systems have experienced significant loss of intertidal flats due to anthropogenic impacts. This paper presents a modeling study conducted to investigate the responses of estuarine hydrodynamics to the loss of intertidal flats caused by anthropogenic actions in Whidbey Basin of Puget Sound on the northwest coast of North America. Changes in salinity intrusion limits in the estuaries, salinity stratification, and circulation in intertidal flats and estuaries were evaluated by comparing model results under the existing baseline condition and the no-flat condition. Model results showed that loss of intertidal flats results in an increase in salinity intrusion, stronger mixing, and a phase shift in salinity and velocity fields in the bay front areas. Model results also indicated that loss of intertidal flats enhances two-layer circulation, especially the bottom water intrusion. Loss of intertidal flats increases the mean salinity but reduces the salinity range in the subtidal flats over a tidal cycle because of increased mixing. Salinity intrusion limits extend upstream in all three major rivers discharging into Whidbey Basin when no intertidal flats are present. Changes in salinity intrusion and estuarine circulation patterns due to loss of intertidal flats affect the nearshore habitat and water quality in estuaries and potentially increase risk of coastal hazards, such as storm surge and coastal flooding. Furthermore, model results suggested the importance of including intertidal flats and the wetting-and-drying process in hydrodynamic simulations when intertidal flats are present in the model domain.

  16. Responses of estuarine circulation and salinity to the loss of intertidal flats – A modeling study

    DOE PAGESBeta

    Yang, Zhaoqing; Wang, Taiping

    2015-08-25

    Intertidal flats in estuaries are coastal wetlands that provide critical marine habitats to support wide ranges of marine species. Over the last century many estuarine systems have experienced significant loss of intertidal flats due to anthropogenic impacts. This paper presents a modeling study conducted to investigate the responses of estuarine hydrodynamics to the loss of intertidal flats caused by anthropogenic actions in Whidbey Basin of Puget Sound on the northwest coast of North America. Changes in salinity intrusion limits in the estuaries, salinity stratification, and circulation in intertidal flats and estuaries were evaluated by comparing model results under the existingmore » baseline condition and the no-flat condition. Model results showed that loss of intertidal flats results in an increase in salinity intrusion, stronger mixing, and a phase shift in salinity and velocity fields in the bay front areas. Model results also indicated that loss of intertidal flats enhances two-layer circulation, especially the bottom water intrusion. Loss of intertidal flats increases the mean salinity but reduces the salinity range in the subtidal flats over a tidal cycle because of increased mixing. Salinity intrusion limits extend upstream in all three major rivers discharging into Whidbey Basin when no intertidal flats are present. Changes in salinity intrusion and estuarine circulation patterns due to loss of intertidal flats affect the nearshore habitat and water quality in estuaries and potentially increase risk of coastal hazards, such as storm surge and coastal flooding. Furthermore, model results suggested the importance of including intertidal flats and the wetting-and-drying process in hydrodynamic simulations when intertidal flats are present in the model domain.« less

  17. Responses of estuarine circulation and salinity to the loss of intertidal flats - A modeling study

    NASA Astrophysics Data System (ADS)

    Yang, Zhaoqing; Wang, Taiping

    2015-12-01

    Intertidal flats in estuaries are coastal wetlands that provide critical marine habitats to support wide ranges of marine species. Over the last century many estuarine systems have experienced significant loss of intertidal flats due to anthropogenic impacts. This paper presents a modeling study conducted to investigate the responses of estuarine hydrodynamics to the loss of intertidal flats in Whidbey Basin of Puget Sound on the northwest coast of North America. Changes in salinity intrusion limits in the estuaries, salinity stratification, and circulation in intertidal flats and estuaries were evaluated by comparing model results under the existing baseline condition and the no-flat condition. Model results showed that loss of intertidal flats results in an increase in salinity intrusion, stronger mixing, and a phase shift in salinity and velocity fields in the bay front areas. Model results also indicated that loss of intertidal flats enhances two-layer circulation, especially the bottom water intrusion. Loss of intertidal flats increases the mean salinity but reduces the salinity range in the subtidal flats over a tidal cycle because of increased mixing. Salinity intrusion limits extend upstream in all three major rivers discharging into Whidbey Basin when no intertidal flats are present. Changes in salinity intrusion and estuarine circulation patterns due to loss of intertidal flats affect the nearshore habitat and water quality in estuaries and potentially increase risk of coastal hazards, such as storm surge and coastal flooding. Lastly, model results suggested the importance of including intertidal flats and the wetting-and-drying process in hydrodynamic simulations when intertidal flats are present in the model domain.

  18. Phenylpyrazole insecticide fipronil induces male infertility in the estuarine meiobenthic crustacean Amphiascus tenuiremis.

    PubMed

    Cary, Tawnya L; Chandler, G Thomas; Volz, David C; Walse, Spencer S; Ferry, John L

    2004-01-15

    Copepods are the most abundant arthropods on earth and are often the most important secondary producers in estuarine/marine food webs. The new GABA (gamma-aminobutyric acid)-disrupting insecticide fipronil (FP) induces unique sex-specific reproductive dysfunction in male meiobenthic copepods, leading to trans-generational population depression at environmentally realistic concentrations (0.63 microg/L). Using a newly developed 96-well microplate lifecycle bioassay, more than 700 individual Stage-I juveniles were reared to adulthood in as short as 12 days in only 200 microL of control (CTL) or 0.63 microg-FP/L seawater solution. Individual virgin male: female pairs were then cross-mated for all possible combinations within and across rearing treatments and allowed to mate for an additional 12 days in CTL or 0.63 microg-FP/L solution. FP at 0.63 microg/L caused no significant lethality to any mating combinations but evoked 73% or 89% inhibition of reproduction when FP-reared males were mated with either a control- or FP-reared female in FP solution, respectively. In contrast, when CTL-reared males were mated with FP-reared females in FP solution, there was no difference in reproductive success compared to FP-free controls. When FP-reared males were mated with either female group in FP-free solution, these mating pairs displayed a 3-day delay in time to brood sac extrusion but ultimately did reproduce. As fipronil (1) has a high K(ow), (2) is persistent in sediments where meiobenthic copepods live, and (3) has been detected in estuarine waters >0.7 microg/L, it may pose high risk to copepod production in estuarine systems. PMID:14750729

  19. Turbine sound may influence the metamorphosis behaviour of estuarine crab megalopae.

    PubMed

    Pine, Matthew K; Jeffs, Andrew G; Radford, Craig A

    2012-01-01

    It is now widely accepted that a shift towards renewable energy production is needed in order to avoid further anthropogenically induced climate change. The ocean provides a largely untapped source of renewable energy. As a result, harvesting electrical power from the wind and tides has sparked immense government and commercial interest but with relatively little detailed understanding of the potential environmental impacts. This study investigated how the sound emitted from an underwater tidal turbine and an offshore wind turbine would influence the settlement and metamorphosis of the pelagic larvae of estuarine brachyuran crabs which are ubiquitous in most coastal habitats. In a laboratory experiment the median time to metamorphosis (TTM) for the megalopae of the crabs Austrohelice crassa and Hemigrapsus crenulatus was significantly increased by at least 18 h when exposed to either tidal turbine or sea-based wind turbine sound, compared to silent control treatments. Contrastingly, when either species were subjected to natural habitat sound, observed median TTM decreased by approximately 21-31% compared to silent control treatments, 38-47% compared to tidal turbine sound treatments, and 46-60% compared to wind turbine sound treatments. A lack of difference in median TTM in A. crassa between two different source levels of tidal turbine sound suggests the frequency composition of turbine sound is more relevant in explaining such responses rather than sound intensity. These results show that estuarine mudflat sound mediates natural metamorphosis behaviour in two common species of estuarine crabs, and that exposure to continuous turbine sound interferes with this natural process. These results raise concerns about the potential ecological impacts of sound generated by renewable energy generation systems placed in the nearshore environment. PMID:23240063

  20. Turbine Sound May Influence the Metamorphosis Behaviour of Estuarine Crab Megalopae

    PubMed Central

    Pine, Matthew K.; Jeffs, Andrew G.; Radford, Craig A.

    2012-01-01

    It is now widely accepted that a shift towards renewable energy production is needed in order to avoid further anthropogenically induced climate change. The ocean provides a largely untapped source of renewable energy. As a result, harvesting electrical power from the wind and tides has sparked immense government and commercial interest but with relatively little detailed understanding of the potential environmental impacts. This study investigated how the sound emitted from an underwater tidal turbine and an offshore wind turbine would influence the settlement and metamorphosis of the pelagic larvae of estuarine brachyuran crabs which are ubiquitous in most coastal habitats. In a laboratory experiment the median time to metamorphosis (TTM) for the megalopae of the crabs Austrohelice crassa and Hemigrapsus crenulatus was significantly increased by at least 18 h when exposed to either tidal turbine or sea-based wind turbine sound, compared to silent control treatments. Contrastingly, when either species were subjected to natural habitat sound, observed median TTM decreased by approximately 21–31% compared to silent control treatments, 38–47% compared to tidal turbine sound treatments, and 46–60% compared to wind turbine sound treatments. A lack of difference in median TTM in A. crassa between two different source levels of tidal turbine sound suggests the frequency composition of turbine sound is more relevant in explaining such responses rather than sound intensity. These results show that estuarine mudflat sound mediates natural metamorphosis behaviour in two common species of estuarine crabs, and that exposure to continuous turbine sound interferes with this natural process. These results raise concerns about the potential ecological impacts of sound generated by renewable energy generation systems placed in the nearshore environment. PMID:23240063

  1. Chemical evolution of a high-level magma system: the Black Mountain volcanic center, southern Nevada

    SciTech Connect

    Vogel, T.A.; Noble, D.C.; Younker, L.W.

    1983-09-01

    A comprehensive study of stratigraphically controlled samples of both lavas and ash-flow tuffs from the Black Mountain volcanic center enables us to evaluate magmatic processes. The results of this study are used to: (1) determine how this high-level magma system developed; (2) compare this system with other similar systems; and (3) correlate ash-flow sheets using their chemical characteristics.

  2. Reconstruction of historical estuarine inflows from tidal records.

    NASA Astrophysics Data System (ADS)

    Leffler, K. E.; Jay, D. A.

    2008-12-01

    The historic, pre-development condition of estuaries is of great interest for assessment of climatological and anthropogenic change, and as baseline data for future management. In the Northeast Pacific basin, the historic condition of estuaries is vital for understanding declines in salmonid populations. River inflow has changed due to climate change, as well as flow regulation, irrigation withdrawals, and channel modification. Estimation of historic flows is an important component of the estimation the overall, pre-development state of an estuary. Tidal height records are generally the longest available environmental record for estuarine systems, and frequently pre-date measurements of river flow, at least in the lower (tidal) reaches of major rivers. Thus, tidal records are attractive dataset to use for reconstruction of river flow. The mechanistic connection between river flow and tidal properties is the frictional interaction of flow with the tide - changes in flow change the tidal frequency spectrum (the latter normalized by the tidal potential or data from a nearby coastal station). Standard and robust harmonic analysis methods are used to estimate tidal constituents from the available high-low water records from Astoria, Oregon, USA from 1855 to 1868. Hourly records from 1870-1871 are used to verify tidal predictions from the high-low dataset. Bootstrap error estimation methods, previously applied to regularly-sampled tidal heights, are adapted to calculate confidence intervals for constituents calculated from the irregularly sampled high-low data. Empirical relationships between measured flow and tidal constituents are developed from the 1925-1955 time period. Using these relations, the riverine inflow to the Columbia estuary is estimated for the 1855-1868 time period, including the historic winter and spring floods of 1861-62, both amongst the larger known for the Columbia.

  3. Modern estuarine siliceous spiculites, Tasmania, Australia: A non-polar link to Phanerozoic spiculitic cherts

    NASA Astrophysics Data System (ADS)

    Reid, C. M.; James, N. P.; Kyser, T. K.; Barrett, N.; Hirst, A. J.

    2008-02-01

    Biosiliceous sedimentary rocks are well known from the geologicrecord and many are correctly interpreted to have formed indeep-water or cold-water environments. Shallow non-polar spiculitesare also known from the rock record, yet no modern analog hasbeen documented for such environments. Bathurst Harbour, anestuarine system in southwest Tasmania, provides this much-neededmodern analog. In this system a sharp halocline separates tannin-richlow-salinity surface waters from clear marine bottom waters.Tannins supply few nutrients and substantially reduce lightpenetration to bottom environments, resulting in a thinned photiczone and the mixing of deeper-water sub-photic biotas of softcorals, bryozoans, and sponges with other organisms more typicalof this temperate shallow-water environment. The well-definedhalocline allows a typically marine biota, including echinoderms,to live in bottom waters of this estuarine setting. The bioclasticfactory, producing both carbonate and siliceous particles, existsin marine subphotic bottom waters of incised channel and shallowrocky environments along the shoreline. Extensive organic-richsoft sediments in protected embayments generate few bioclasts,but contain allochthonous sponge spicules transported from theadjacent bioclastic factory. Trapping of organic material withinthe estuarine system lowers sediment pH and promotes dissolutionof carbonate biofragments, resulting in preferential preservationof siliceous sponge spicules. This situation implies that manybiosiliceous neritic deposits in the rock record may be theresult of similar preferential preservation.

  4. Geogenic arsenic and other trace elements in the shallow hydrogeologic system of Southern Poopó Basin, Bolivian Altiplano.

    PubMed

    Ormachea Muñoz, Mauricio; Wern, Hannes; Johnsson, Fredrick; Bhattacharya, Prosun; Sracek, Ondra; Thunvik, Roger; Quintanilla, Jorge; Bundschuh, Jochen

    2013-11-15

    important process for the mobilisation of As in the shallow groundwaters of the region. Continuous monitoring and expansion of monitoring systems are necessary prerequisites for better understanding of the pattern of As mobilisation in the Southern Poopó Basin. PMID:24091126

  5. The 2012-2014 eruptive cycle of Copahue Volcano, Southern Andes. Magmatic-Hydrothermal system interaction and manifestations.

    NASA Astrophysics Data System (ADS)

    Morales, Sergio; Alarcón, Alex; Basualto, Daniel; Bengoa, Cintia; Bertín, Daniel; Cardona, Carlos; Córdova, Maria; Franco, Luis; Gil, Fernando; Hernandez, Erasmo; Lara, Luis; Lazo, Jonathan; Mardones, Cristian; Medina, Roxana; Peña, Paola; Quijada, Jonathan; San Martín, Juan; Valderrama, Oscar

    2015-04-01

    Copahue Volcano (COPV), in Southern Andes of Chile, is an andesitic-basaltic stratovolcano, which is located on the western margin of Caviahue Caldera. The COPV have a NE-trending fissure with 9 aligned vents, being El Agrio the main currently active vent, with ca. 400 m in diameter. The COPV is placed into an extensive hydrothermal system which has modulated its recent 2012-2014 eruptive activity, with small phreatic to phreatomagmatic eruptions and isolated weak strombolian episodes and formation of crater lakes inside the main crater. Since 2012, the Southern Andes Volcano Observatory (OVDAS) carried out the real-time monitoring with seismic broadband stations, GPS, infrasound sensors and webcams. In this work, we report pre, sin, and post-eruptive seismic activity of the last two main eruptions (Dec, 2012 and Oct, 2014) both with different seismic precursors and superficial activity, showing the second one a particularly appearance of seismic quiescence episodes preceding explosive activity, as an indicator of interaction between magmatic-hydrothermal systems. The first episode, in late 2012, was characterized by a low frequency (0.3-0.4 Hz and 1.0-1.5 Hz) continuous tremor which increased gradually from background noise level amplitude to values of reduced displacement (DR), close to 50 cm2 at the peak of the eruption, reaching an eruptive column of ~1.5 km height. After few months of recording low energy seismicity, a sequence of low frequency, repetitive and low energy seismic events arose, with a frequency of occurrence up to 300 events/hour. Also, the VLP earthquakes were added to the record probably associated with magma intrusion into a deep magmatic chamber during all stages of eruptive process, joined to the record of VT seismicity during the same period, which is located throughout the Caviahue Caldera area. Both kind of seismic patterns were again recorded in October 2014, being the precursor of the new eruptive cycle at this time as well as the

  6. Links between carbonate productivity and ENSO variability in the southern California Current System for the past 2 Kyrs

    NASA Astrophysics Data System (ADS)

    Abella-Gutiérrez, J. L.; Herguera, J. C.

    2014-12-01

    San Lázaro Basin (SLB) is a suboxic basin characteristic for its very high sedimentation rates (1mm/yr) and is located in the dynamic southern boundary of the California Current System (CCS). This southern boundary of the CCS generally extends further south during spring into early summer and retracts towards the north during fall and winter, and this pattern is further amplified or reduced on different time scales, (e.i. interannual timescales by El Niño and La Niña events, or multidecadal ones by the Pacific Decadal Oscillation (PDO)). These oceanographic conditions are related with important differences in the base of the food chain; when the boundary migrates to northern latitudes, the presence of relatively warmer tropical and subtropical waters further stratify the water column, a period when coccolithophorids dominate the microplankton web structure. On the other side, diatoms flourish when the wind-driven circulation expand the subarctic water masses of the CCS to the south and upwelling cells are generated. We find in our cores XRF Ca counts (1 mm resolution) highly correlate with CaCO3 measurements (R=0.56), this last one showing a general decreasing trend over the past 2 Kyrs. The Ca spectrum analysis shows significant peaks for periods centered at 28, 40, 60, 120 yr. The centennial mode of variability of the Ca record shows correlations with Drought area Index from North America. When the variance of this mode is considered, similarities arises with intensity and number of ENSO events from Equatorial archives. Decadal variations of the record are highly correlated (R>0.8) with instrumental measurements of Kaplan sea surface temperature, and the PDO. We will discuss the implications of these periods in the carbonate record and the links between them and other paleoceanographic records in the Pacific.

  7. Variability and trends of ocean acidification in the Southern California Current System: A time series from Santa Monica Bay

    NASA Astrophysics Data System (ADS)

    Leinweber, A.; Gruber, N.

    2013-07-01

    We investigate the temporal variability and trends of pH and of the aragonite saturation state, Ωarag, in the southern California Current System on the basis of a 6 year time series from Santa Monica Bay, using biweekly observations of dissolved inorganic carbon and combined calculated and measured alkalinity. Median values of pH and Ωarag in the upper 20 m are comparable to observations from the subtropical gyres, but the temporal variability is at least a factor of 5 larger, primarily driven by short-term upwelling events and mesoscale processes. Ωarag and pH decrease rapidly with depth, such that the saturation horizon is reached already at 130 m, on average, but it occasionally shoals to as low as 30 m. No statistically significant linear trends emerge in the upper 100 m, but Ωarag and pH decrease, on average, at rates of -0.009±0.006 yr-1 and -0.004±0.003 yr-1 in the 100-250 m depth range. These are somewhat larger, but not statistically different from the expected trends based on the recent increase in atmospheric CO2. About half of the variability in the deseasonalized data can be explained by the El Niño Southern Oscillation, with warm phases (El Niño) being associated with above normal pH and Ωarag. The observed variability and trend in Ωarag and pH is well captured by a multiple linear regression model on the basis of a small number of readily observable independent variables. This permits the estimation of these variables for related sites in the region.

  8. Choice chamber experiments to test the attraction of postflexion Rhabdosargus holubi larvae to water of estuarine and riverine origin

    NASA Astrophysics Data System (ADS)

    James, Nicola C.; Cowley, Paul D.; Whitfield, Alan K.; Kaiser, Horst

    2008-03-01

    Although the recruitment of larvae and juveniles of marine fishes into estuaries has been well documented, little is known about the factors governing the immigration of estuary-associated marine fishes into estuaries. Fishes have a well-developed sense of smell and it has been suggested by several workers that olfactory cues of freshwater or estuarine origin serve as stimuli, attracting larvae and juveniles of estuary-associated species into estuaries. Attraction of postflexion Rhabdosargus holubi larvae to estuary and river water from the Kowie estuarine system, South Africa, was measured using a rectangular choice chamber. In experiments, conducted during peak recruitment periods, larvae selected estuary and river water with a significantly higher frequency than sea water. This study, the first to assess the possible role of olfaction in the recruitment process of an estuary-associated marine fish species, demonstrates that larvae are able to recognise water from different origins, probably based on odour.

  9. PCBs and DDE in Tree Swallow (Tachycineta bicolor) Eggs and Nestlings from an Estuarine PCB Superfund Site, New Bedford Harbor, MA, U.S.A.

    EPA Science Inventory

    While breeding tree swallows (Tachycineta bicolor) have been used as biomonitors for freshwater sites, we report the first use of this species to assess the transfer of breeding ground contaminants from an estuarine system. Eggs and nestlings were collected from nest boxes locat...

  10. Nearshore currents on the southern Namaqua shelf of the Benguela upwelling system

    NASA Astrophysics Data System (ADS)

    Fawcett, A. L.; Pitcher, G. C.; Shillington, F. A.

    2008-05-01

    Nearshore currents of the southern Namaqua shelf were investigated using data from a mooring situated three and a half kilometres offshore of Lambert's Bay, downstream of the Cape Columbine upwelling cell, on the west coast of South Africa. This area is susceptible to harmful algal blooms (HABs) and wind-forced variations in currents and water column structure are critical in determining the development, transport and dissipation of blooms. Time series of local wind data, and current and temperature profile data are described for three periods, considered to be representative of the latter part of the upwelling season (27 January-22 February), winter conditions (5-29 May) and the early part of the upwelling season (10 November-12 December) in 2005. Differences observed in mean wind strength and direction between data sets are indicative of seasonal changes in synoptic meteorological conditions. These quasi-seasonal variations in wind forcing affect nearshore current flow, leading to mean northward flow in surface waters early in the upwelling season when equatorward, upwelling-favourable winds are persistent. Mean near-surface currents are southward during the latter part of the upwelling season, consistent with more prolonged periods of relaxation from equatorward winds, and under winter conditions when winds were predominantly poleward. Within these seasonal variations in mean near-surface current direction, two scales of current variability were evident within all data sets: strong inertial oscillations were driven by diurnal winds and introduced vertical shear into the water column enhancing mixing across the thermocline, while sub-inertial current variability was driven by north-south wind reversals at periods of 2-5 days. Sub-inertial currents were found to lag wind reversals by approximately 12 h, with a tendency for near-surface currents to flow poleward in the absence of wind forcing. Consistent with similar sites along the Californian and Iberian coasts

  11. Predictive Relationships for pH and Carbonate Saturation in the Southern California Current System Using Oxygen and Temperature Data

    NASA Astrophysics Data System (ADS)

    Alin, S. R.; Feely, R. A.; Dickson, A. G.; Hernandez-Ayon, J. M.; Juranek, L. W.; Ohman, M. D.; Goericke, R.

    2010-12-01

    The California Current System is expected to experience the ecological impacts of ocean acidification earlier than most other ocean regions because marine waters in the North Pacific are among the oldest in the global oceans and natural upwelling processes in this eastern boundary current system bring CO2-rich water masses to the surface in coastal oceans during late spring-early fall months. We used a multiple linear regression (MLR) approach to generate predictive models using oxygen and temperature as proxy variables to reconstruct pH and carbonate saturation states in the Southern California Bight. The calibration data set included high-quality measurements of dissolved inorganic carbon, alkalinity, oxygen, temperature, salinity, and nutrients and was collected during a cruise from British Columbia to Baja California in May-June 2007. The resulting relationships predicting pH and aragonite and calcite saturation states (Ω) from oxygen and temperature data were robust, with r2 values >0.98 and root mean square errors of 0.020 (pH), 0.048 (Ωarag), and 0.075 (Ωcalc). Predicted vs. measured ocean acidification conditions (i.e. pH, Ωarag, and Ωcalc) matched very well for seven verification data sets collected between 2008 and 2010 during quarterly CalCOFI cruises in the Southern California Bight and during several sampling dates on an Ensenada transect occupied several times between 2006 and 2010. Over sub-decadal time scales, these predictive models provide a valuable tool for reconstructing historical time-series of ocean acidification conditions in the California Current Ecosystem where historical inorganic carbon measurements are scarce. Reconstructed pH and saturation state values based on CalCOFI oxygen and temperature data for all cruises between 2005 and 2010 reveal a seasonal cycle in the upper water column, with higher pH and Ω values present during the winter cruises, and stronger gradients including much lower pH and Ω values during spring through

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

    PubMed Central

    Ortega-Cisneros, Kelly; Scharler, Ursula M.

    2015-01-01

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

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

    PubMed

    Ortega-Cisneros, Kelly; Scharler, Ursula M

    2015-01-01

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

  14. Predicting stochastic systems by noise sampling, and application to the El Niño-Southern Oscillation.

    PubMed

    Chekroun, Mickaël David; Kondrashov, Dmitri; Ghil, Michael

    2011-07-19

    Interannual and interdecadal prediction are major challenges of climate dynamics. In this article we develop a prediction method for climate processes that exhibit low-frequency variability (LFV). The method constructs a nonlinear stochastic model from past observations and estimates a path of the "weather" noise that drives this model over previous finite-time windows. The method has two steps: (i) select noise samples--or "snippets"--from the past noise, which have forced the system during short-time intervals that resemble the LFV phase just preceding the currently observed state; and (ii) use these snippets to drive the system from the current state into the future. The method is placed in the framework of pathwise linear-response theory and is then applied to an El Niño-Southern Oscillation (ENSO) model derived by the empirical model reduction (EMR) methodology; this nonlinear model has 40 coupled, slow, and fast variables. The domain of validity of this forecasting procedure depends on the nature of the system's pathwise response; it is shown numerically that the ENSO model's response is linear on interannual time scales. As a result, the method's skill at a 6- to 16-month lead is highly competitive when compared with currently used dynamic and statistic prediction methods for the Niño-3 index and the global sea surface temperature field. PMID:21730171

  15. Guayape-Papalutla fault system: A continuous Cretaceous structure from southern Mexico to the Chortís block? Tectonic implications

    NASA Astrophysics Data System (ADS)

    Silva-Romo, G.

    2008-01-01

    Recent papers have opened the debate over whether the Chortísblock was located off the coast of southern Mexico or in a moreoutboard position, and this led me to explore whether correlationswith older structures could be established to determine theevolution of the southwest corner of the North America plate.In this paper I hypothesize that the Papalutla fault of Mexicoand the Guayape fault system of Honduras, both considered tobe terrane boundaries, were roughly continuous in the Cretaceous,extending from southern Mexico to the Chortís block.They influenced Early Cretaceous clastic sedimentation of theZicapa Formation on the Guerrero-Morelos Platform (southernMexico) and the Tepemechin Formation of the Central Chortísterrane (Honduras). The units accumulated in fault-bounded basinsassociated with left-lateral slip. The basins developed in theCentral Chortís terrane and Guerrero-Morelos Platform.Both geological entities appear to represent a continuous Cretaceousgeologic province characterized by a trangression that occurredearlier in Honduras than in southern Mexico. This nonrotationalhypothesis for the location of the Chortís block adjacentto southern Mexico during the Cretaceous is consistent withnortheastward displacement of the Caribbean plate during Cretaceoustime and implies 1500 km of Chortís block displacementduring the Cenozoic.

  16. Evaluation of the Precision Agricultural Landscape Modeling System (PALMS) in the Semiarid Texas Southern High Plains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Accurate models to simulate the soil water balance in semiarid cropping systems are needed to evaluate management practices for soil and water conservation in both irrigated and dryland production systems. The objective of this study was to evaluate the application of the Precision Agricultural Land...

  17. Emergy analysis of a silvo-pastoral system, a case study in southern Portugal

    EPA Science Inventory

    The Mediterranean silvo-pastoral system known as Montado, in Portugal, is a complex land use system composed of an open tree stratum in various densities and an herbaceous layer, used for livestock grazing. Livestock also profit from the acorns, and the grazing contributes to avo...

  18. Evaluation of the precision agricultural landscape modeling system (PALMS) in the semiarid Texas southern high plains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Accurate models to simulate the soil water balance in semiarid cropping systems are needed to evaluate management practices for soil and water conservation in both irrigated and dryland production systems. The objective of this study was to evaluate the application of the Precision Agricultural Land...

  19. Genetically Diverse Clostridium difficile Strains Harboring Abundant Prophages in an Estuarine Environment

    PubMed Central

    Hargreaves, K. R.; Colvin, H. V.; Patel, K. V.; Clokie, J. J. P.

    2013-01-01

    Clostridium difficile is the leading cause of antibiotic-associated diarrheal disease in health care settings across the world. Despite its pathogenic capacity, it can be carried asymptomatically and has been found in terrestrial and marine ecosystems outside hospital environments. Little is known about these environmental strains, and few studies have been conducted on estuarine systems. Although prophage abundance and diversity are known to occur within clinical strains, prophage carriage within environmental strains of C. difficile has not previously been explored. In this study, we isolated C. difficile from sites sampled in two consecutive years in an English estuarine system. Isolates were characterized by PCR ribotype, antibiotic resistance, and motility. The prevalence and diversity of prophages were detected by transmission electron microscopy (TEM) and a phage-specific PCR assay. We show that a dynamic and diverse population of C. difficile exists within these sediments and that it includes isolates of ribotypes which are associated with severe clinical infections and those which are more frequently isolated from outside the hospital environment. Prophage carriage was found to be high (75%), demonstrating that phages play a role in the biology of these strains. PMID:23913427

  20. Abandoned mine drainage in the Swatara Creek Basin, southern anthracite coalfield, Pennsylvania, USA: 2. performance of treatment systems

    USGS Publications Warehouse

    Cravotta, Charles A., III

    2010-01-01

    A variety of passive and semi-passive treatment systems were constructed by state and local agencies to neutralize acidic mine drainage (AMD) and reduce the transport of dissolved metals in the upper Swatara Creek Basin in the Southern Anthracite Coalfield in eastern Pennsylvania. To evaluate the effectiveness of selected treatment systems installed during 1995–2001, the US Geological Survey collected water-quality data at upstream and downstream locations relative to each system eight or more times annually for a minimum of 3 years at each site during 1996–2007. Performance was normalized among treatment types by dividing the acid load removed by the size of the treatment system. For the limestone sand, open limestone channel, oxic limestone drain, anoxic limestone drain (ALD), and limestone diversion well treatment systems, the size was indicated by the total mass of limestone; for the aerobic wetland systems, the size was indicated by the total surface area of ponds and wetlands. Additionally, the approximate cost per tonne of acid treated over an assumed service life of 20 years was computed. On the basis of these performance metrics, the limestone sand, ALD, oxic limestone drain, and limestone diversion wells had similar ranges of acid-removal efficiency and cost efficiency. However, the open limestone channel had lower removal efficiency and higher cost per ton of acid treated. The wetlands effectively attenuated metals transport but were relatively expensive considering metrics that evaluated acid removal and cost efficiency. Although the water-quality data indicated that all treatments reduced the acidity load from AMD, the ALD was most effective at producing near-neutral pH and attenuating acidity and dissolved metals. The diversion wells were effective at removing acidity and increasing pH of downstream water and exhibited unique potential to treat moderate to high flows associated with storm flow conditions.

  1. When did the subduction first initiate in the southern Paleo-Asian Ocean: New constraints from a Cambrian intra-oceanic arc system in West Junggar, NW China

    NASA Astrophysics Data System (ADS)

    Ren, Rong; Han, Bao-Fu; Xu, Zhao; Zhou, Yin-Zhang; Liu, Bo; Zhang, Lei; Chen, Jia-Fu; Su, Li; Li, Jiao; Li, Xian-Hua; Li, Qiu-Li

    2014-02-01

    We report here a Cambrian southward-subducting intra-oceanic arc system in the southern West Junggar, NW China, where an immature arc occurred initially on SSZ-type ophiolites and finally evolved into a more mature one. The immature arc is dominantly represented by Early-Middle Cambrian (∼510 Ma) low-K tholeiitic felsic rocks, whereas the mature arc is characterized by Late Cambrian (∼495 Ma) medium- and high-K calc-alkaline felsic and mafic rocks. The SSZ-type ophiolites show remarkable depletion of Nb and Ta and contain high-Cr spinel (Cr# > 0.6), resembling these formed in the forearc. Altogether, they record the initiation of subduction and transformation of crust during early subduction of the Paleo-Asian Ocean in the southern part of the Central Asian Orogenic Belt (CAOB). The subduction initiation might occur in the Early Cambrian (>515 Ma), as constrained by both the SSZ-type ophiolites (516 Ma) and the oldest arc plutons (515-509 Ma) that crosscut the ophiolites. The immature felsic plutons have high SiO2 (>72 wt%) contents and variable MgO (0.42-1.49 wt%) and Mg# values (22-62). Crustal anatexis may be responsible for the genesis of those plutons and thus the transformation from oceanic to continental crust. These results, combined with regional data, convincingly indicate that it is one of the oldest intra-oceanic arc systems in the southern CAOB, which may mark the initial subduction of the Paleo-Asian Ocean in its southern part, much later than those reported in the north. An archipelago-type model is proposed for the evolution of the southern West Junggar and has implications for the development of the southern part of the CAOB.

  2. Hydrogen Isotope Evidence for Giant Meteoric-Hydrothermal Systems Associated with Extension and Magmatism in the Southern Canadian Cordillera

    NASA Astrophysics Data System (ADS)

    Holk, G. J.; McCarthy, A.

    2014-12-01

    Over 400 published mineral and fluid inclusion δD values from the southern Canadian Cordillera and our new data from the Eocene Penticton Group Volcanics and Coryell Intrusive Suite of the Southern Omineca Belt and the Western Metamorphic Belt of the Central Coast Orogen are compiled using GIS. δDH2O is estimated using published D/H fractionation factors at 400°C; the error is ±20‰, small enough to distinguish deep magmatic/metamorphic fluids from meteoric-hydrothermal fluids. Histogram plots of δDH2O values estimated from minerals reveal peaks at δD = -60‰ (deep fluid) and ­-110‰ (Early Cenozoic meteoric-hydrothermal fluid); this provides a clear distinction between the two kinds of fluid. Our analysis reveals that syn-extensional meteoric-hydrothermal systems (δDH2O < -80‰) affected the eastern margin of the Coast Ranges Batholith between latitude 49° and 55° and the Omineca Belt between latitude 49° and 52°45'; both regions were affected by detachment faulting during late stages of magmatism in the Early Cenozoic (e.g., Parrish et al., 1988; Crawford et al., 2009). Zones that escaped the effects of meteoric-hydrothermal systems, preserving the D/H signature of deep fluids (δD > -80‰), include the Western Metamorphic Belt, the Western and Central Coast Ranges Batholith, the belt of Jurassic metamorphism that extends from the Cariboo Mountains to the Purcell Mountains, and the deepest structural levels of the Shuswap Metamorphic Core Complex; most of these samples have quartz-feldspar 18O/16O fractionations indicative of magmatic temperatures. High δDH2O values (> -50‰) suggest seawater alteration of the plutons of Vancouver Island (Magaritz and Taylor, 1986). Histogram plots of vein quartz fluid inclusion δD values (Nesbitt and Muehlenbachs, 1995) reveal three peaks that include the two produced by the mineral δD values, but these data are dominated by a large peak at δD = -150, a value similar to modern meteoric waters in the region

  3. 7. VIEW OF SOUTHERN PACIFIC RAILROAD BRIDGE, LOWER CHORD, LATERAL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. VIEW OF SOUTHERN PACIFIC RAILROAD BRIDGE, LOWER CHORD, LATERAL BRACING AND FLOOR SYSTEM, LOOKING WEST. - Southern Pacific Railroad Bridge, Spanning Rio Grande at Southern Pacific Railroad, El Paso, El Paso County, TX

  4. The Southern California Coastal Ocean Observing System (SCCOOS): Developing A Coastal Observation System To Enable Both Science Based Decision Making And Scientific Discovery

    NASA Astrophysics Data System (ADS)

    Terrill, E.; John, O.

    2005-05-01

    The Southern California Coastal Ocean Observing System (SCCOOS) is a consortium that extends from Northern Baja CA in Mexico to Morro Bay at the southern edge of central California, and aims to streamline, coordinate, and further develop individual institutional efforts by creating an integrated, multidisciplinary coastal observatory in the Bight of Southern California for the benefit of society. By leveraging existing infrastructure, partnerships, and private, local, state, and federal resources, SCCOOS is developing a fully operational coastal observation system to address issues related to coastal water quality, marine life resources, and coastal hazards for end user communities spanning local, state, and federal interests. However, to establish a sensible observational approach to address these societal drivers, sound scientific approaches are required in both the system design and the transformation of data to useful products. Since IOOS and coastal components of the NSF Ocean Observatories Initiative (OOI) are not mutually exclusive within this framework, the SCCOOS consortium of observatory implementers have created an organizational structure that encourages dovetailing of OOI into the routine observations provided by the operational components of a regional IOOS. To begin the development, SCCOOS has grant funding from the California Coastal Conservancy as part of a $21M, statewide initiative to establish a Coastal Ocean Currents Monitoring Program, and funding from NOAA's Coastal Observing Technology System (COTS). In addition, SCCOOS is leveraging IT development that has been supported by the NSF Information Technology Research program Real-time observatories, Applications,and Data Manageemnt Network (ROADNET), and anticipates using developments which will result from the NSF Laboratory for Ocean Observatory Knowledge Integration Grid (LOOKING) program. The observational components now funded at SCCOOS include surface current mapping by HF radar; high

  5. Six thousand years of coastline evolution in the Guadalfeo deltaic system (southern Iberian Peninsula)

    NASA Astrophysics Data System (ADS)

    Jabaloy-Sánchez, Antonio; Lobo, Francisco José; Azor, Antonio; Martín-Rosales, Wenceslao; Pérez-Peña, José Vicente; Bárcenas, Patricia; Macías, Jorge; Fernández-Salas, Luis Miguel; Vázquez-Vílchez, Mercedes

    2014-02-01

    The 4000 BC to present-day coastal and shallow-marine changes of the Guadalfeo River deltaic system (southeast Spain) are studied using historic maps, aerial photographs, diverse submarine data, and hydrodynamic models. The deltaic system evolved with little anthropic influence until the 1940s, when the river mouth was diverted to the west. During the pre-diversion stage, the system evolved from an estuary to a delta due to the enormous sediment yield in the catchment, induced both by anomalously wet climate conditions and by deforestation practices. Accordingly, the coastline advanced significantly (up to 3.3 m year- 1) during this period, particularly during the 1500 to 1873 interval. The estimate for volumetric changes in the deltaic system shows very high specific sediment yield values (around 60-65 t ha- 1 year- 1) in the catchment. The deltaic system mainly evolved by cannibalization of the older, lobate outlet depocentre after the river diversion and the generation of a more elongated depocentre coincident with the current outlet due to enhanced lateral redistribution of sediments (from east to west). The construction of two major dams in the trunk river in the last 30 years has severely blocked sediment supply to the system, although expected coastline erosion has been partially mitigated by longshore sediment redistribution.

  6. A Paleozoic Japan-type subduction-accretion system in the Beishan orogenic collage, southern Central Asian Orogenic Belt

    NASA Astrophysics Data System (ADS)

    Song, Dongfang; Xiao, Wenjiao; Windley, Brian F.; Han, Chunming; Tian, Zhonghua

    2015-05-01

    Magmatic arcs ascribed to oceanic lithosphere subduction played a dominant role in the construction of the accretionary Central Asian Orogenic Belt (CAOB). The Beishan orogenic collage, situated between the Tianshan Orogen to the west and the Inner Mongolia Orogen to the east, is a key area to understanding the subduction and accretionary processes of the southern CAOB. However, the nature of magmatic arcs in the Beishan and the correlation among different tectonic units along the southern CAOB are highly ambiguous. In order to investigate the subduction-accretion history of the Beishan and put a better spatial and temporal relationship among the tectonic belts along the southern CAOB, we carried out detailed field-based structural geology and LA-ICP-MS zircon U-Pb geochronological as well as geochemical studies along four cross-sections across crucial litho-tectonic units in the central segment of the Beishan, mainly focusing on the metamorphic assemblages and associated plutons and volcanic rocks. The results show that both the plutonic and volcanic rocks have geochemical characteristics similar to those of subduction-related rocks, which favors a volcanic arc setting. Zircons from all the plutonic rocks yield Phanerozoic ages and the plutons have crystallization ages ranging from 464 ± 2 Ma to 398 ± 3 Ma. Two volcanic-sedimentary rocks yield zircons with a wide age range from Phanerozoic to Precambrian with the youngest age peaks at 441 Ma and 446 Ma, estimated to be the time of formation of the volcanic rocks. These new results, combined with published data on ophiolitic mélanges from the central segment of the Beishan, favor a Japan-type subduction-accretion system in the Cambrian to Carboniferous in this part of the Paleo-Asian Ocean. The Xichangjing-Niujuanzi ophiolite probably represents a major suture zone separating different tectonic units across the Beishan orogenic collage, while the Xiaohuangshan-Jijitaizi ophiolitic mélange may represent a

  7. Modelling the Emission And/or Absorption Features in the High Resolution Spectra of the Southern Binary System: HH Car

    NASA Astrophysics Data System (ADS)

    Koseoglu, Dogan; Bakış, Hicran

    2016-07-01

    High-resolution spectra (R=48000) of the southern close binary system, HH Car, has been analyzed with modern analysis techniques. Precise absolute parameters were derived from the simultaneous solution of the radial velocity, produced in this study and the light curves, published. According to the results of these analyses, the primary component is an O9 type main sequence star while the secondary component is a giant/subgiant star with a spectral type of B0. Hα emissions can be seen explicitly in the spectra of HH Car. These features were modelled using the absolute parameters of the components. Since components of HH Car are massive early-type stars, mass loss through stellar winds can be expected. This study revealed that the components of HH Car have stellar winds and the secondary component loses mass to the primary. Stellar winds and the gas stream between the components were modelled as a hot shell around the system. It is determined that the interaction between the winds and the gas stream leads to formation of a high temperature impact region.

  8. Predicting stochastic systems by noise sampling, and application to the El Niño-Southern Oscillation

    PubMed Central

    Chekroun, Mickaël David; Kondrashov, Dmitri; Ghil, Michael

    2011-01-01

    Interannual and interdecadal prediction are major challenges of climate dynamics. In this article we develop a prediction method for climate processes that exhibit low-frequency variability (LFV). The method constructs a nonlinear stochastic model from past observations and estimates a path of the “weather” noise that drives this model over previous finite-time windows. The method has two steps: (i) select noise samples—or “snippets”—from the past noise, which have forced the system during short-time intervals that resemble the LFV phase just preceding the currently observed state; and (ii) use these snippets to drive the system from the current state into the future. The method is placed in the framework of pathwise linear-response theory and is then applied to an El Niño–Southern Oscillation (ENSO) model derived by the empirical model reduction (EMR) methodology; this nonlinear model has 40 coupled, slow, and fast variables. The domain of validity of this forecasting procedure depends on the nature of the system’s pathwise response; it is shown numerically that the ENSO model’s response is linear on interannual time scales. As a result, the method’s skill at a 6- to 16-month lead is highly competitive when compared with currently used dynamic and statistic prediction methods for the Niño-3 index and the global sea surface temperature field. PMID:21730171

  9. Assessing indigenous knowledge systems and climate change adaptation strategies in agriculture: A case study of Chagaka Village, Chikhwawa, Southern Malawi

    NASA Astrophysics Data System (ADS)

    Nkomwa, Emmanuel Charles; Joshua, Miriam Kalanda; Ngongondo, Cosmo; Monjerezi, Maurice; Chipungu, Felistus

    In Malawi, production from subsistence rain fed agriculture is highly vulnerable to climate change and variability. In response to the adverse effects of climate change and variability, a National Adaptation Programme of Action is used as framework for implementing adaptation programmes. However, this framework puts limited significance on indigenous knowledge systems (IKS). In many parts of the world, IKS have shown potential in the development of locally relevant and therefore sustainable adaptation strategies. This study was aimed at assessing the role of IKS in adaptation to climate change and variability in the agricultural sector in a rural district of Chikhwawa, southern Malawi. The study used both qualitative data from focus group and key informant interviews and quantitative data from household interviews and secondary data to address the research objectives. The study established that the local communities are able to recognise the changes in their climate and local environment. Commonly mentioned indicators of changing climatic patterns included delayed and unpredictable onset of rainfall, declining rainfall trends, warming temperatures and increased frequency of prolonged dry spells. An analysis of empirical data corroborates the people's perception. In addition, the community is able to use their IKS to adapt their agricultural systems to partially offset the effects of climate change. Like vulnerability to climate change, IKS varies over a short spatial scale, providing locally relevant adaptation to impacts of climate change. This paper therefore advocates for the integration of IKS in programmes addressing adaptation to climate change and vulnerability. This will serve to ensure sustainable and relevant adaptation strategies.

  10. Noise analysis of the seismic system employed in the northern and southern California seismic nets

    USGS Publications Warehouse

    Eaton, J.P.

    1984-01-01

    The seismic networks have been designed and operated to support recording on Develocorders (less than 40db dynamic range) and analog magnetic tape (about 50 db dynamic range). The principal analysis of the records has been based on Develocorder films; and background earth noise levels have been adjusted to be about 1 to 2 mm p-p on the film readers. Since the traces are separated by only 10 to 12 mm on the reader screen, they become hopelessly tangled when signal amplitudes on several adjacent traces exceed 10 to 20 mm p-p. Thus, the background noise level is hardly more than 20 db below the level of largest readable signals. The situation is somewhat better on tape playbacks, but the high level of background noise set to accomodate processing from film records effectively limits the range of maximum-signal to background-earth-noise on high gain channels to a little more than 30 db. Introduction of the PDP 11/44 seismic data acquisition system has increased the potential dynamic range of recorded network signals to more than 60 db. To make use of this increased dynamic range we must evaluate the characteristics and performance of the seismic system. In particular, we must determine whether the electronic noise in the system is or can be made sufficiently low so that background earth noise levels can be lowered significantly to take advantage of the increased dynamic range of the digital recording system. To come to grips with the complex problem of system noise, we have carried out a number of measurements and experiments to evaluate critical components of the system as well as to determine the noise characteristics of the system as a whole.

  11. Geochemistry of the Koshelev Volcano-Hydrothermal System, Southern Kamchatka, Russia

    NASA Astrophysics Data System (ADS)

    Taran, Y.; Kalacheva, E.

    2015-12-01

    Koshelev is the southernmost volcano of the Kamchatkan volcanic front where magmatic plumbing systems of the Kamchatkan subduction zone cross a thick layer of the oil-gas-bearing Neogene sedimentary strata of Western Kamchatka. The volcanic massive hosts a powerful hydrothermal system, which has been drilled in early 1980s. Deep wells tapped a hot (ca. 300ºC) saline solution (up to 40 g/L of Cl), whereas the upper part of the system is a typical steam cap with temperature close to 240ºC. Two hydrothermal fields of the volcano (Upper and Lower) discharge saturated or super-heated (up to 150ºC) steam and are characterized by numerous hot pools and low flow-rate springs of steam-heated waters enriched in boron and ammonia. There is also a small lateral group of warm Na-Ca-Cl-SO4 springs (40ºC). We report here our data and review the literature geochemical data on the chemical and isotopic composition of waters and hydrothermal vapours of the Koshelev system. Data on the gas composition include He and C isotopes, as well as the chemical and isotopic composition of light hydrocarbons. Water geochemistry includes literature data on water isotopes of the deep brine and trace elements and REE of steam-heated waters. A conceptual model of the system is presented and discussed.

  12. Sequence model for coastal-plain depositional systems of the Upper Triassic (Betic Cordillera, southern Spain)

    NASA Astrophysics Data System (ADS)

    Pérez-López, A.

    1996-01-01

    The deposits of the Upper Triassic of the Subbetic Zone (Betic Cordillera) offer an example of semi-arid fluvial deposits passing into shallow-water facies through a mud-flat environment. From the study of the vertical changes in facies, a sequence model is proposed for the Upper Triassic succession, relating, for each systems tract, the changes in sea level, the accommodation space and the evolution of the facies within a coastal-plain depositional system. The lowstand depositional system is made up of a package of thick, amalgamated sandstone strata limited below by an erosive surface with little incision. These are sheet-flood deposits and channel fills which form part of an extensive alluvial system in which wide but shallow water courses appear, with the development of extensive sand bars. These sandbodies from the lowstand phase often contain mudrock intraclasts, plant remains and erosive surfaces. The accommodation space being extremely limited, the preservation of the floodplain or mud-flat deposits and palaeosols is practically nil. The result is an amalgamation of extensive sandbodies with fine intercalated claystone levels. The transgressive depositional systems consist mainly of a red claystone series, although the first sediments of these systems are composed of sandstone with major claystone intercalations. These lower sandy levels of the transgressive phase do not exceed 50 cm in thickness and usually contain burrows and small-scale sedimentary structures. In the intermediate part of the red claystone series of this transgressive episode of saline mud-flat facies, there are sandstone levels of a little-developed fluvial system with channels which migrate laterally due to the rise of the base level. In addition, the predominance and the great development of the red claystone facies reflect the increase in the accommodation space, which permitted a greater accumulation of sediments during a transgressive phase than during the lowstand phase. In the

  13. Neogene-Quaternary Volcanic Alignments in the Transantarctic Mountains and West Antarctic Rift System of Southern Victoria Land, Antarctica

    NASA Astrophysics Data System (ADS)

    Paulsen, T. S.; Wilson, T. J.

    2004-12-01

    Neogene-Quaternary volcanism in southern Victoria Land, Antarctica, produced the Erebus Volcanic Province, a suite of alkaline volcanic rocks that extend from the Transantarctic Mountains rift-flank uplift to offshore localities within the West Antarctic rift system. We are mapping volcanic vent patterns in the province to detect alignments indicative of stress/strain patterns during rift evolution. In the southern sector of the Erebus Volcanic Province in the Royal Society Range Block of the Transantarctic Mountains, mapping shows that elliptical scoria cones, fissures, dikes, and linear vent arrays define volcanic alignments that have a dominant NNE trend, with subsidiary WNW trends. Age data for the alignments suggest that this pattern persisted from 14.6 to 0.25 Ma. We are currently completing mapping along an east-west transect crossing the rift margin, and results obtained so far within the rift region indicate a similar pattern of alignments. On the northern flank of Mount Morning, a large volcano just to the east of the Royal Society Range, elliptical scoria cones and linear vent arrays define volcanic alignments that have a dominant NE trend, with a subsidiary NNW trend. Available age data suggest that many of these cone alignments may be of Quaternary age. At Brown Peninsula, further east from the rift flank, cone alignments trend NNE and available ages range from 2 to 3 Ma. To the east of Brown Peninsula, cone alignments trend NW at Black Island, but are of uncertain age; age data on Black Island range from 11 to 3.4 Ma. At White Island, the farthest east into the rift, cone alignments trend NNE and available age data suggest volcanism as young as 0.2 Ma. Although some differences in cone alignment trends are apparent between the rift flank and the rift system across our transect, both regions appear to be dominated by NE trending alignments, which implies a WNW to NW minimum horizontal stress (Shmin) direction. This is oblique to the ENE Shmin Cape

  14. Distribution of oxidizable organic c fractions in soils under cacao agroforestry systems in Southern Bahia, Brazil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Agroforestry systems can play a major role in the sequestration of carbon (C) because of their higher input of organic materials to the soil. The importance of organic carbon to the physical, chemical, and biological aspects of soil quality is well recognized. However, total organic carbon measureme...

  15. Distribution of organic C oxidizable fractions in soils under cacao agroforestry systems in southern Bahia, Brazil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Agroforestry systems can play a major role in the sequestration of carbon (C) because of their higher input of organic material to the soil. The importance of organic carbon to the physical, chemical, and biological aspects of soil quality is well recognized. However, total organic carbon measuremen...

  16. Geochemical and Isotopic Interpretations of Groundwater Flow in the Oasis Valley Flow System, Southern Nevada

    SciTech Connect

    J.M. Thomas; F.C. Benedict, Jr.; T.P. Rose; R.L. Hershey; J.B. Paces; Z.E. Peterman; I.M. Farnham; K.H. Johannesson; A.K. Singh; K.J. Stetzenbach; G.B. Hudson; J.M. Kenneally; G.F. Eaton; D.K. Smith

    2003-01-08

    This report summarizes the findings of a geochemical investigation of the Pahute Mesa-Oasis Valley groundwater flow system in southwestern Nevada. It is intended to provide geochemical data and interpretations in support of flow and contaminant transport modeling for the Western and Central Pahute Mesa Corrective Action Units.

  17. The Environmental Belief Systems of Organic and Conventional Farmers: Evidence from Central-Southern England

    ERIC Educational Resources Information Center

    Kings, David; Ilbery, Brian

    2010-01-01

    Little comparative work has been conducted on the environmental belief systems and behaviours of conventional and organic farmers, especially in relation to farming culture, the environment and lowland farmland avifauna. Adopting a modified behavioural approach, this paper analyses the ways in which the environmental attitudes and understandings…

  18. Cover crop use for weed management in Southern reduced-tillage vegetable cropping systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    With growing agricultural demands from both conventional and organic systems comes the need for sustainable practices to ensure long-term productivity. Implementation of reduced- or no-till practices offers a number of environmental benefits for agricultural land and maintains adequate yield for cu...

  19. Using new electrofishing technology to amp-up fish sampling in estuarine habitats.

    PubMed

    Warry, F Y; Reich, P; Hindell, J S; McKenzie, J; Pickworth, A

    2013-04-01

    A prototype, boat-mounted electrofisher capable of operation in estuarine waters (where electrical conductivities often exceed 20 000 µS cm(-1)) was assessed. Electrofishing was compared to fyke and mesh netting in four riverine estuaries and to seining in a lagoonal estuary (consisting of a series of brackish coastal lakes separated from the sea by a barrier system of sand dunes). Fish assemblage composition, length distributions and the probability of detecting ecological fish guilds (relating to estuary use, position in the water column and body size) were compared among gears. The assemblage composition of electrofishing samples differed from those of fyke nets in all riverine estuaries and from mesh netting in two. The assemblage composition of electrofishing samples differed from those of seining in structured seagrass habitats of the lagoonal estuary. When all species were pooled, the electrofisher sampled a broader range of lengths than either fyke or mesh netting in riverine estuaries or seining in lagoonal estuaries. The bias of electrofishing and netting towards particular species and size classes affected the probability of detecting some ecological guilds, highlighting the potential implications of gear choice on understanding estuarine ecological function. The detection of guilds varied with gear type and environmental conditions, including stratification, water depth and surface electrical conductivity. Assessments with the aim to characterize the structure of fish assemblages will benefit from the use of multiple gears. Electrofishing shows immense promise for discretely sampling highly structured habitats to test hypotheses about their use. PMID:23557295

  20. Structure and diversity of functional guilds in the microbial nitrogen cycle of estuarine sediments

    NASA Astrophysics Data System (ADS)

    Ward, B. B.; Francis, C. A.; Taroncher-Oldenburg, G.; Cornwell, J.

    2002-12-01

    Denitrification is a major flux of nitrogen in Chesapeake Bay, an estuary with a long residence time and high organic and inorganic nutrient inputs from the large surrounding watershed. The estuarine system spans a complex gradient of salinity and many correlated chemical constituents, from its upper bay and river freshwater end members to its nearly full strength seawater lower Bay. Denitrification rates in sediments, computed from net nitrogen fluxes in simulated in situ core incubations, show distinct reproducible patterns along the Bay. Highest rates are observed in sediments from the low salinity, high nitrate upper stations in the Bay and Choptank River. Lower rates occur in the low nitrate, oxygen depleted mid bay sediments and in the metabolically less active south Bay sediments. Gene sequences for nitrite reductase, the key enzyme in denitrification, show very high diversity in Bay and River sediments. On the basis of clone library sequences alone, however, there are distinct clades and patterns indicating highest diversity in the upper Bay and River sediments and lower diversity in the lower Bay sediments. Using a DNA microarray containing many individual nitrite reductase sequences, we investigated the population structure of denitrification genes along the estuarine gradient. Evaluation of gene expression patterns, in addition to presence/absence or abundance of individual genes, will allow a direct assessment of the links between diversity and biogeochemical transformation rates for particular functional guilds. The rate of denitrification and its regulation by environmental variables may be reflected in patterns of guild composition and activity.

  1. Analytical characterization of selective benthic flux components in estuarine and coastal waters

    USGS Publications Warehouse

    King, Jeffrey N.

    2011-01-01

    Benthic flux is the rate of flow across the bed of a water body, per unit area of bed. It is forced by component mechanisms, which interact. For example, pressure gradients across the bed, forced by tide, surface gravity waves, density gradients, bed–current interaction, turbulence, and terrestrial hydraulic gradients, drive an advective benthic flux of water and constituents between estuarine and coastal waters, and surficial aquifers. Other mechanisms also force benthic flux, such as chemical gradients, bioturbation, and dispersion. A suite of component mechanisms force a total benthic flux at any given location, where each member of the suite contributes a component benthic flux. Currently, the types and characteristics of component interactions are not fully understood. For example, components may interact linearly or nonlinearly, and the interaction may be constructive or destructive. Benthic flux is a surface water–groundwater interaction process. Its discharge component to a marine water body is referred to, in some literature, as submarine groundwater discharge. Benthic flux is important in characterizing water and constituent budgets of estuarine and coastal systems. Analytical models to characterize selective benthic flux components are reviewed. Specifically, these mechanisms are for the component associated with the groundwater tidal prism, and forced by surface gravity wave setup, surface gravity waves on a plane bed, and the terrestrial hydraulic gradient. Analytical models are applied to the Indian River Lagoon, Florida; Great South Bay, New York; and the South Atlantic Bight in South Carolina and portions of North Carolina.

  2. Intracellular pH Recovery Rates of Hemocytes from Estuarine and Open Ocean Bivalve Species Following In vitro Acid Challenge

    NASA Astrophysics Data System (ADS)

    Croxton, A.; Wikfors, G.

    2013-12-01

    Decreasing pH in estuarine systems is a growing concern for researchers studying mollusk species. Debates continue on whether estuarine bivalve species are more or less vulnerable to ocean acidification than marine species because estuaries can present multiple environmental stressors. The aim of this study is to understand the homeostatic mechanisms of bivalve hemocytes following exposure to extracellular acid treatment. Previous measurements using fluorescent SNARF probes and flow-cytometry have determined the intracellular pH of hemocytes from several bivalve species (eastern oyster, bay scallop, northern quahog, soft-shell clam, and blue mussel) to range between 7.0-7.4. In the present study of four bivalve species, recovery rate profiles were determined for intracellular hemocyte pH following addition of acid to hemolymph in vitro. These profiles indicate that soft-shell clams and bay scallops maintained homeostasis with very little change in intracellular pH. In contrast, an initial drop in intracellular pH in northern quahogs was followed by a steady recovery of intracellular pH. Contrasting results between species appear to be unrelated to mineral shell composition (aragonite vs. calcite) or habitat location (infaunal vs. epifaunal). The next phase of this study will be to determine if offshore species (surfclams and sea scallops) will have similar responses. Results from these studies will provide a better understanding of the physiological responses of estuarine and marine species exposed to acidified environments.

  3. Spatial patterns of distribution and the influence of seasonal and abiotic factors on demersal ichthyofauna in an estuarine tropical bay.

    PubMed

    da Silva, D R; Paranhos, R; Vianna, M

    2016-07-01

    This study focused on the influence of local-scale environmental factors on key metrics of fish community structure and function at Guanabara Bay, an estuarine system that differs from all other south-western Atlantic estuaries due to the influence of an annual low-intensity upwelling event during late spring and summer, between November and March, when a warm rainy climate prevails. The spatial patterns of the bottom temperature and salinity were more heterogeneous during the rainy season than the dry season, being linked to total precipitation and seasonal oceanographic events. The study identified 130 species and 45 families, placing Guanabara Bay as one of the most species-rich tropical estuarine ecosystems, far exceeding 22 other Brazilian estuaries. These results, in addition to characteristics such as a relatively well-preserved mangrove forest, high productivity and favourable conditions for the growth and reproduction of estuarine species, indicate that Guanabara Bay plays a central role in supporting large populations of fishes, including commercially important species. PMID:27401484

  4. Spatial analysis of the trophic interactions between two juvenile fish species and their preys along a coastal-estuarine gradient

    NASA Astrophysics Data System (ADS)

    Kopp, Dorothée; Le Bris, Hervé; Grimaud, Lucille; Nérot, Caroline; Brind'Amour, Anik

    2013-08-01

    Coastal and estuarine systems provide nursery grounds for many marine fish species. Their productivity has been correlated with terrigeneous inputs entering the coastal-estuarine benthic food web, thereby favouring the establishment of fish juveniles. Studies in these ecosystems often describe the nursery as a single large habitat without verifying nor considering the presence of contiguous habitats. Our study aimed at identifying different habitats based on macrozoobenthic communities and morpho-sedimentary characteristics and assessing the trophic interactions between fish juveniles and their benthic preys within these habitats. It included 43 sampling sites covering 5 habitats in which we described taxonomically and quantitatively the invertebrates and fish communities with stable isotopes and gut contents. It suggested that the benthic common sole Solea solea displayed feeding plasticity at the population level, separating the juveniles (G0) from the older fish (G1) into different "feeding sub-populations". Size-based feeding plasticity was also observable in the spatial occupancy of that species in the studied bay. The demersal pouting, Trisopterus luscus, equally used the different habitats but displayed low feeding plasticity across and inside each habitat. Stable isotopes proved to be powerful tools to study the spatial distribution of trophic interactions in complex ecosystems like the bay of Vilaine and to define optimal habitats for fish that use the coastal-estuarine ecosystem as nursery grounds.

  5. Contourite systems in the region of the southern São Paulo Plateau escarpment, South Atlantic

    NASA Astrophysics Data System (ADS)

    Borisov, D. G.; Murdmaa, I. O.; Ivanova, E. V.; Levchenko, O. V.; Yutsis, V. V.; Frantseva, T. N.

    2013-07-01

    Seismoacoustic investigations with a high-resolution parametric echo-sounder "SES 2000 deep" carried out on cruises 33, 35, and 37 of the R/V Akademik Ioffe revealed several erosional-depositional contourite systems on the São Paulo Plateau escarpment and its toe in the South Atlantic. Two contourite terraces related to interfaces between different water masses are observable on the escarpment. These terraces presumably reflect the activity of internal waves and turbulent eddies. The São Paulo contourite channel and genetically related drift are traceable along the escarpment toe. Changes in planktonic foraminiferal assemblages in Core AI-2563 retrieved from the summit of the São Paulo contourite drift suggest a shallowing of the Weddell Sea Deep Water mass during glacial times. It is established that the contour current of the Weddell Sea Deep Water and Lower Circumpolar Water considerably affect the formation of contourite depositional systems on the escarpment and its toe.

  6. Dynamics of a large, restless, rhyolitic magma system at Laguna del Maule, southern Andes, Chile

    USGS Publications Warehouse

    Singer, Brad S.; Andersen, Nathan L.; Le Mével, Hélène; Feigl, Kurt L.; DeMets, Charles; Tikoff, Basil; Thurber, Clifford H.; Jicha, Brian R.; Cardonna, Carlos; Córdova, Loreto; Gil, Fernando; Unsworth, Martyn J.; Williams-Jones, Glyn; Miller, Craig W.; Fierstein, Judith; Hildreth, Edward; Vazquez, Jorge A.

    2014-01-01

    Explosive eruptions of large-volume rhyolitic magma systems are common in the geologic record and pose a major potential threat to society. Unlike other natural hazards, such as earthquakes and tsunamis, a large rhyolitic volcano may provide warning signs long before a caldera-forming eruption occurs. Yet, these signs—and what they imply about magma-crust dynamics—are not well known. This is because we have learned how these systems form, grow, and erupt mainly from the study of ash flow tuffs deposited tens to hundreds of thousands of years ago or more, or from the geophysical imaging of the unerupted portions of the reservoirs beneath the associated calderas. The Laguna del Maule Volcanic Field, Chile, includes an unusually large and recent concentration of silicic eruptions. Since 2007, the crust there has been inflating at an astonishing rate of at least 25 cm/yr. This unique opportunity to investigate the dynamics of a large rhyolitic system while magma migration, reservoir growth, and crustal deformation are actively under way is stimulating a new international collaboration. Findings thus far lead to the hypothesis that the silicic vents have tapped an extensive layer of crystal-poor, rhyolitic melt that began to form atop a magmatic mush zone that was established by ca. 20 ka with a renewed phase of rhyolite eruptions during the Holocene. Modeling of surface deformation, magnetotelluric data, and gravity changes suggest that magma is currently intruding at a depth of ~5 km. The next phase of this investigation seeks to enlarge the sets of geophysical and geochemical data and to use these observations in numerical models of system dynamics.

  7. Design and operation specifications of an active monitoring system for detecting southern resident killer whales

    SciTech Connect

    Deng, Zhiqun; Carlson, Thomas J.; Xu, Jinshan; Martinez, Jayson J.; Weiland, Mark A.; Mueller, Robert P.; Myers, Joshua R.; Jones, Mark E.

    2011-09-30

    Before final approval is given to the Snohomish County Public Utility District No. 1 for deploying the first tidal power devices in the United States in an open water environment, a system to manage the potential risk of injury to killer whales due to collision with moving turbine blades must be demonstrated. The Pacific Northwest National Laboratory (PNNL) is tasked with establishing the performance requirements for, constructing, and testing a prototype marine animal alert system for triggering temporary turbine shutdown when there is risk of collision with a killer whale. To develop a system that relies on active sonar two critical areas must be investigated - the target strength of killer whales and the frequency content of commercially available active sonar units. PNNL studied three target strength models: a simple model, the Fourier matching model, and the Kirchoff-ray mode model. Using target strength measurements of bottlenose dolphins obtained by previous researchers and assuming killer whales share similar morphology and structure, PNNL extrapolated the target strength of an adult killer whale 7.5 m in length at a frequency of 67 kHz. To study the frequency content of a commercially available sonar unit, direct measurements of the signal transmitted by the sonar were obtained by using a hydrophone connected to a data acquisition system in both laboratory and field conditions. The measurements revealed that in addition to the primary frequency of 200 kHz, there is a secondary frequency component at 90 kHz, which is within the hearing range of killer whales. The amplitude of the 90-kHz frequency component is above the hearing threshold of killer whales but below the threshold for potential injuries.

  8. Influence of a burrowing, metal-tolerant polychaete on benthic metabolism, denitrification and nitrogen regeneration in contaminated estuarine sediments.

    PubMed

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

    2013-03-15

    We investigated the effects of the burrowing cirratulid polychaete Cirriformia filigera (Delle Chiaje, 1828) on benthic respiration and nitrogen regeneration in metal-contaminated estuarine sediments using laboratory mesocosms. C. filigera is a dominant component of assemblages in the most severely contaminated sediments within the Derwent estuary, southern Australia. In the presence of C. filigera sediment O2 consumption doubled, with approximately 55% of this increase due to their respiration and the remaining 45% attributable to oxidation reactions and increased microbial respiration associated with burrow walls. Combined NO3 and NO2 fluxes were unaffected. The addition of labile organic matter did not affect benthic fluxes, in the presence or absence of C. filigera, presumably due to the short timeframe of the experiment and naturally enriched test sediments. The results suggest that a combination of tolerance and burrowing activity enables this species to provide an ecosystem service in the removal of N from contaminated sites. PMID:23398743

  9. Coevolution of hydraulic, soil and vegetation processes in estuarine wetlands

    NASA Astrophysics Data System (ADS)

    Trivisonno, Franco; Rodriguez, Jose F.; Riccardi, Gerardo; Saco, Patricia; Stenta, Hernan

    2014-05-01

    Estuarine wetlands of south eastern Australia, typically display a vegetation zonation with a sequence mudflats - mangrove forest - saltmarsh plains from the seaward margin and up the topographic gradient. Estuarine wetlands are among the most productive ecosystems in the world, providing unique habitats for fish and many terrestrial species. They also have a carbon sequestration capacity that surpasess terrestrial forest. Estuarine wetlands respond to sea-level rise by vertical accretion and horizontal landward migration, in order to maintain their position in the tidal frame. In situations in which buffer areas for landward migration are not available, saltmarsh can be lost due to mangrove encroachment. As a result of mangrove invasion associated in part with raising estuary water levels and urbanisation, coastal saltmarsh in parts of south-eastern Australia has been declared an endangered ecological community. Predicting estuarine wetlands response to sea-level rise requires modelling the coevolving dynamics of water flow, soil and vegetation. This paper presents preliminary results of our recently developed numerical model for wetland dynamics in wetlands of the Hunter estuary of NSW. The model simulates continuous tidal inflow into the wetland, and accounts for the effect of varying vegetation types on flow resistance. Coevolution effects appear as vegetation types are updated based on their preference to prevailing hydrodynamic conditions. The model also considers that accretion values vary with vegetation type. Simulations are driven using local information collected over several years, which includes estuary water levels, accretion rates, soil carbon content, flow resistance and vegetation preference to hydraulic conditions. Model results predict further saltmarsh loss under current conditions of moderate increase of estuary water levels.

  10. Survival of Escherichia coli and Salmonella spp. in estuarine environments.

    PubMed

    Rhodes, M W; Kator, H

    1988-12-01

    Survival of Escherichia coli and Salmonella spp. in estuarine waters was compared over a variety of seasonal temperatures during in situ exposure in diffusion chambers. Sublethal stress was measured by both selective-versus-resuscitative enumeration procedures and an electrochemical detection method. E. coli and Salmonella spp. test suspensions, prepared to minimize sublethal injury, were exposed in a shallow tidal creek and at a site 7.1 km further downriver. Bacterial die-off and sublethal stress in filtered estuarine water were inversely related to water temperature. Salmonella spp. populations exhibited significantly less die-off and stress than did E. coli at water temperatures of less than 10 degrees C. Although the most pronounced reductions (ca. 3 log units) in test bacteria occurred during seasonally warm temperatures in the presence of the autochthonous microbiota, 10(2) to 10(4) test cells per ml remained after 2 weeks of exposure to temperatures of greater than 15 degrees C. Reductions in test bacteria were associated with increases in the densities of microflagellates and plaque-forming microorganisms. These studies demonstrated the survival potential of enteric bacteria in estuarine waters and showed that survival was a function of interacting biological and physical factors. PMID:3066291

  11. Generation of an estuarine sediment plume by a tropical storm

    NASA Astrophysics Data System (ADS)

    Cheng, Peng; Li, Ming; Li, Yun

    2013-02-01

    Tropical Storm Lee (2011) caused a record flood in the Susquehanna River which discharged about 6.7 million tons of suspended sediments into the Bay, an amount equal to the input of 6 average years. The flood-carried sediment produced a large sediment plume that covered one half of Chesapeake Bay with the maximum suspended sediment concentration exceeding 2500 mg L-1. Three stages were identified in the development of the sediment plume, corresponding to three dominant forcing mechanisms, i.e., river flow, estuarine circulation, and sediment settling. Most of the flood-carried sediments were deposited in the Bay within 20 days. Sands were dumped in the Susquehanna Flats with a maximum thickness of 10 cm, while fine-grained sediments were dusted over a wide area in the upper Bay with a maximum thickness of 4 cm. Long-term simulation of the post-storm period showed that a majority of the flood sediments were redistributed to accumulate in the estuarine turbidity maximum region due to flood-ebb asymmetry in tidal suspension and advection by estuarine circulation and tidal flows while the rest were transported seaward and deposited in the mid-Bay. It is estimated that the flood delivered 9 months of particulate nitrogen and over 1 year of particulate phosphorus supplies to the estuary. This catastrophic event may change the geological history and exacerbate water-quality decline in the American largest estuary.

  12. Effects of leached mirex on experimental communities of estuarine animals.

    PubMed

    Tagatz, M E; Borthwick, P W; Ivey, J M; Knight, J

    1976-01-01

    Experimental communities of various estuarine animals in outdoor tanks were exposed to a continuous flow of water containing mirex for 10 weeks. The mirex was leached from fire ant bait (0.3% active ingredient) by fresh water which was then mixed with salt water to yield exposure concentrations averaging 0.038 mug/L. The experiment simulated runoff from treated land into estuarine areas. Mortality of grass shrimp (Palaemonetes vulgaris), pin, shrimp (Penaeus duorarum), common mud crabs (Panopeus herbstii), and striped hermit crabs (Clibanarius vittatus) was significantly high in tanks containing the toxicant. Mortality of ribbed mussels (Modiolus demissus) and American oysters (Crassostrea virginica) was significantly lower in treated tanks, probably because numbers of both species of crabs, which ate the bivalves, were reduced. Sheepshead minnows (Cyprinodon variegatus) were least affected by mirex. Almost all deaths occurred after 10 or more days of exposure. All exposed animals accumulated mirex, with maximum concentrations ranging from 5,500X (pink shrimp) to 73,700X (soft tissues of oysters) above the concentration in the water. Sand substratum contained mirex up to 1,500X that in the water. The study demonstrated that mirex can be leached from bait by fresh water and concentrated by and affect survival of members in an experimental estuarine community. PMID:999334

  13. Morphotectonic evolution of two depressions at the southern border of the Baikal rift system

    NASA Astrophysics Data System (ADS)

    Vogt, Henri; Vogt, Thea

    2007-05-01

    Detailed study of two dry depressions in the Baikal rift system: the E-W Khoito Ghol-Tunka-Bistraya depression and the SW-NE Gusinoje-Ivolga depression, aims to provide a better understanding of tectonic control on the intershoulder relief evolution after the rift opened. Both depressions are grabens and both feature a suite of 10-20 km-wide basins alternating with more or less massive highs. Field and laboratory analysis shows that this pattern is of recent tectonic origin and that local breaking-up and subsidence followed the general sinking which originally formed the grabens. The subsidence belts seem to have gradually shifted north and northeastwards. Geomorphological analysis reveals that in both depressions the highs are remnants of a former pediment which was broken up. The young basins display numerous relevant hydrographic anomalies of the secondary channels and a general water-logging. They also suggest that the subsidence belts have gradually shifted north-and northeastwards. In the Gusinoje-Ivolga depression evidence was found of a Plio-Pleistocene river course, parallel to the Selenga river, which was later dismantled by the breaking-up. This depression, parallel to the Baikal rift and belonging to the Mesozoic system of grabens in the Caledonian fold belt, seems to have been included into the general system of rifts during the Pliocene tectonic phase. As for the main hydrographic axes, the Selenga river was set on a Palaeogene-age planation surface before the first tectonic phase and kept its original course. The Irkut river flowed in the Khoito Gol-Tunka-Bistraya depression after the first tectonic phase and was not affected by the later breaking-up. In contrast, the secondary drainage network is largely discordant. Despite their different geotectonic contexts, the two depressions show a similar development of relief pattern ,which poses the question of the style of rift dynamics after the main Pliocene tectonic phase.

  14. Application of the Global Positioning System to crustal deformation measurements. 3: Result from the southern California borderlands

    SciTech Connect

    Larson, K.M.

    1993-12-01

    Five years of measurements from the Global Positioning System (GPS) satellites collected between 1986 and 1991 are used to investigate deformation in the offshore regions of southern California. GPS provides the first practical technique to make precise geodetic measurements in the region. The geodetic network is situated along the California coastline from Vandenberg (120.6 deg W, 34.6 deg N) to San Diego, with additional sites on Santa Cruz, San Nicolas, Santa Catalina, Santa Rosa, and San Clemente Islands. The precision of horizontal interstation vectors is subcentimeter, and the interstation vector rate between Owens Valley Radio Observatory (OVRO) and Vandenberg agrees with the very long baseline interferometry derived rate to within one standard deviation. No significant motion is observed in th e western Santa Barbara Channel between Vandenberg and Santa Rosa Island, 0.5 +/- 1.6 mm/yr, where the quoted uncertainties are one standard deviation. Motions in the eastern Santa Barbara Channel are consistent with compressional deformation of 6 +/- 1 mm/yr at N16 +/- 3 deg E. This motion is in agreement with seismicity and an independent geodetic analysis for the period 1971-1987 (Larsen, 1991). San Clemente Island is moving relative to San Diego at the rate of 5.9 +/- 1.8/yr at a direction of N38 +/- 20 deg W. The motion between San Nicolas Island and San Clemente Island, 0.8 +/- 1.5 mm/yr, is insignificant.

  15. Efficacy of entecavir and tenofovir in chronic hepatitis B under treatment in the public health system in southern Brazil

    PubMed Central

    Pereira, Camila V; Tovo, Cristiane Valle; Grossmann, Thiago K; Mirenda, Henrique; Dal-Pupo, Bruna B; de Almeida, Paulo RL; de Mattos, Angelo A

    2016-01-01

    There are about 350 million hepatitis B virus (HBV) carriers worldwide and chronic HBV is considered a major public health problem. The objective of the present study was to assess the effectiveness of the nucleos(t)ide analogues tenofovir (TDF) and entecavir (ETV) in the treatment of chronic HBV. A cross-sectional study was carried out from March-December 2013, including all patients with chronic HBV, over 18 years of age, undergoing therapy through the public health system in southern Brazil. Only the data relating to the first treatments performed with TDF or ETV were considered. Retreatment, co-infection, transplanted or immunosuppressed patients were excluded. Six hundred and forty patients were evaluated, of which 336 (52.5%) received TDF and 165 (25.8%) ETV. The other 139 (21.7%) used various combinations of nucleos(t)ide analogues and were excluded. The negativation of viral load was observed in 87.3% and 78.8% and the negativation of hepatitis B e antigen was achieved in 79% and 72% of those treated with ETV or TDF, respectively. Negativation of hepatitis B surface antigen was not observed. There was no occurrence of adverse effects. This is a real-life study demonstrating that long-term treatment with ETV and TDF is both safe and effective. PMID:27074254

  16. Teleseismic P-wave Delay Time Tomography of the southern Superior Province and Midcontinent Rift System (MRS) Region

    NASA Astrophysics Data System (ADS)

    Bollmann, T. A.; van der Lee, S.; Frederiksen, A. W.; Wolin, E.; Aleqabi, G. I.; Revenaugh, J.; Wiens, D. A.; Darbyshire, F. A.

    2014-12-01

    The Superior Province Rifting Earthscope Experiment (SPREE) and the northern midwest footprint of USArray's Transportable Array recorded continuous ground motion for a period of 2.5 years. From around 400 M>5.5 teleseismic earthquakes recorded at 337 stations, we measured body wave delay times for 255 of these earthquakes. The P wave delays are accumulated over more than 45 thousand wave paths with turning points in the lower mantle. We combine these delay times with a similar number delay times used in previous tomographic studies of the study region. The latter delay times stem from fewer stations, including Polaris and CNSN stations, and nearly a thousand earthquakes. We combine these two sets of delay times to image the three-dimensional distribution of seismic velocity variations beneath the southern Superior Province and surrounding provinces. This combined data coverage is illustrated in the accompanying figure for a total number of 447 stations . The coverage and the combined delays form the best configuration yet to image the three-dimensional distribution of seismic P and S-wave velocity variations beneath the southern Superior and surrounding provinces. Closely spaced stations (~12 km) along and across the MRS provide higher resolving power for lithospheric structure beneath the rift system. Conforming to expectations that the entire region is underlain by thick, cool lithosphere, a mean delay of -.55 +/- .54 s. This is very similar to the mean delays -.6s +/- .37s measured for this region before 2012. Event corrections range from -.2 +/-.54 s and correlate with tectonics for 80% of the earthquakes. An inversion of these nearly one hundred thousand P and around thirty thousand S-wave delay times for high-resolution P and S-wave velocity structure, respectively, does not show structures that are obviously related to the crustal signature of the MRS. None of structures imaged, align with or have a similar shape to the high Mid-continent Gravity Anomaly

  17. Ocean warming and seabird communities of the southern California Current System (1987-98): response at multiple temporal scales

    NASA Astrophysics Data System (ADS)

    Hyrenbach, K. David; Veit, Richard R.

    2003-08-01

    Declines in ocean productivity and shifts in species assemblages along the West Coast of North America during the second half of the XXth century have been attributed to the concurrent warming of the California Current. This paper addresses changes in the avifauna off southern California between May 1987 and September 1998, in response to shifting water mass distributions over short (<1 year) and long (interannual) temporal scales. More specifically, our research focuses on the relative importance of distinct foraging guilds and species assemblages with an affinity for warm and cold water. Over the long term, the avifauna off southern California shifted from a 'high-productivity' community typical of eastern boundary upwelling systems, to a 'low-productivity' assemblage similar to those inhabiting the subtropical gyres. Overall seabird abundance decreased; the relative importance of cold-water seabirds that dive in pursuit of prey declined; and warm-water species that feed at the surface and plunge to capture prey became more numerous. These community-level changes are consistent with the northward shifts in species ranges and the declining ocean productivity anticipated as a result of global warming. However, the response of individual taxa with an affinity for warm-water and cold-water conditions has been more difficult to predict, due to differences in species-specific responses to ocean warming. The three cold-water species investigated (Sooty Shearwater Puffinus griseus, Cassin's Auklet Ptychoramphus aleuticus, and Rhinoceros Auklet Cerorhinca monocerata) decreased in abundance during this study. On the other hand, only one of the six warm-water species considered (Pink-footed Shearwater, Puffinus creatopus) increased significantly over the long term. Yet, the warm-water Leach's Storm-petrel ( Oceanodroma leucorhoa) increased between 1987 and 1993, and then declined between 1994 and 1998. Moreover, cross-correlations between seasonally adjusted anomalies of

  18. Southern California Seismic Network: New Design and Implementation of Redundant and Reliable Real-time Data Acquisition Systems

    NASA Astrophysics Data System (ADS)

    Saleh, T.; Rico, H.; Solanki, K.; Hauksson, E.; Friberg, P.

    2005-12-01

    The Southern California Seismic Network (SCSN) handles more than 2500 high-data rate channels from more than 380 seismic stations distributed across southern California. These data are imported real-time from dataloggers, earthworm hubs, and partner networks. The SCSN also exports data to eight different partner networks. Both the imported and exported data are critical for emergency response and scientific research. Previous data acquisition systems were complex and difficult to operate, because they grew in an ad hoc fashion to meet the increasing needs for distributing real-time waveform data. To maximize reliability and redundancy, we apply best practices methods from computer science for implementing the software and hardware configurations for import, export, and acquisition of real-time seismic data. Our approach makes use of failover software designs, methods for dividing labor diligently amongst the network nodes, and state of the art networking redundancy technologies. To facilitate maintenance and daily operations we seek to provide some separation between major functions such as data import, export, acquisition, archiving, real-time processing, and alarming. As an example, we make waveform import and export functions independent by operating them on separate servers. Similarly, two independent servers provide waveform export, allowing data recipients to implement their own redundancy. The data import is handled differently by using one primary server and a live backup server. These data import servers, run fail-over software that allows automatic role switching in case of failure from primary to shadow. Similar to the classic earthworm design, all the acquired waveform data are broadcast onto a private network, which allows multiple machines to acquire and process the data. As we separate data import and export away from acquisition, we are also working on new approaches to separate real-time processing and rapid reliable archiving of real-time data

  19. 77 FR 25962 - Proposed Information Collection; Comment Request; Coastal and Estuarine Land Conservation...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-02

    ... and Estuarine Land Conservation Planning, Protection or Restoration AGENCY: National Oceanic and..., restoration, or construction projects. The required information enables NOAA to implement the CELCP, under...

  20. Southern (In)hospitality

    ERIC Educational Resources Information Center

    Hamilton, Kendra

    2005-01-01

    This article presents the results of "The Status of Race Equity and Diversity in Public Higher Education in the South," an analysis of trends in admissions, enrollment and completion at public colleges and universities in the 19 Southern and border states that maintained segregated systems of higher education in 1954. While work on the project…

  1. The Metro Atlanta Solar System: A Southern Slice of the Sky

    NASA Astrophysics Data System (ADS)

    De Pree, Christopher G.

    2010-01-01

    The Metro Atlanta Solar System (MASS) is a scale model solar system centered at the Bradley Observatory plaza on the campus of Agnes Scott College, a liberal arts women's college located in Decatur, GA. The MASS model was dedicated on September 11, 2009 in celebration of the International Year of Astronomy (IYA). One of the planets (Uranus) was installed at Hartsfield Jackson International Airport in May 2009 as part of the From Earth to the Universe (FETTU) exhibit that will be at the airport through the end of January 2010. MASS places scaled images of the planets at locations throughout the city, along their orbits at distances scaled to the size of a 30 foot diameter Sun (the observing plaza) located at Agnes Scott College. The planetary images are those from the airport FETTU exhibition, so the model serves as a way to connect the entire city of Atlanta to the airport images. In this model, 1 AU = 1 km. We discuss the planning, implementation and future uses of this model.

  2. Chemical abundance analysis of symbiotic giants - III. Metallicity and CNO abundance patterns in 24 southern systems

    NASA Astrophysics Data System (ADS)

    Gałan, Cezary; Mikołajewska, Joanna; Hinkle, Kenneth H.; Joyce, Richard R.

    2016-01-01

    The elemental abundances of symbiotic giants are essential to address the role of chemical composition in the evolution of symbiotic binaries, to map their parent population, and to trace their mass transfer history. However, the number of symbiotic giants with fairly well determined photospheric composition is still insufficient for statistical analyses. This is the third in a series of papers on the chemical composition of symbiotic giants determined from high-resolution (R ˜ 50 000), near-infrared spectra. Here we present results for 24 S-type systems. Spectrum synthesis methods employing standard local thermal equilibrium analysis and atmosphere models were used to obtain photospheric abundances of CNO and elements around the iron peak (Fe, Ti, Ni, and Sc). Our analysis reveals metallicities distributed in a wide range from slightly supersolar ([Fe/H] ˜ +0.35 dex) to significantly subsolar ([Fe/H] ˜ -0.8 dex) but principally with near-solar and slightly subsolar metallicity ([Fe/H] ˜ -0.4 to -0.3 dex). The enrichment in 14N isotope, found in all these objects, indicates that the giants have experienced the first dredge-up. This was confirmed in a number of objects by the low 12C/13C ratio (5-23). We found that the relative abundance of [Ti/Fe] is generally large in red symbiotic systems.

  3. Sedimentology and paleoecology of an Eocene Oligocene alluvial lacustrine arid system, Southern Mexico

    NASA Astrophysics Data System (ADS)

    Beraldi-Campesi, Hugo; Cevallos-Ferriz, Sergio R. S.; Centeno-García, Elena; Arenas-Abad, Concepción; Fernández, Luis Pedro

    2006-10-01

    A depositional model of the Eocene-Oligocene Coatzingo Formation in Tepexi de Rodríguez (Puebla, Mexico) is proposed, based on facies analysis of one of the best-preserved sections, the Axamilpa Section. The sedimentary evolution is interpreted as the retrogradation of an alluvial system, followed by the progressive expansion of an alkaline lake system, with deltaic, palustrine, and evaporitic environments. The analysis suggests a change towards more arid conditions with time. Fossils from this region, such as fossil tracks of artiodactyls, aquatic birds and cat-like mammals, suggest that these animals traversed the area, ostracods populated the lake waters, and plants grew on incipient soils and riparian environments many times throughout the history of the basin. The inferred habitat for some fossil plants coincides with the sedimentological interpretation of an arid to semiarid climate for that epoch. This combined sedimentological-paleontological study of the Axamilpa Section provides an environmental context in which fossils can be placed and brings into attention important biotic episodes, like bird and camelid migrations or the origin of endemic but extinct plants in this area.

  4. The Liuqu Conglomerate: early Miocene basin development related to deformation within the Great Counter Thrust system, southern Tibet

    NASA Astrophysics Data System (ADS)

    Leary, R.; DeCelles, P. G.; Quade, J.

    2013-12-01

    Cenozoic sedimentary basins along the Yarlung-Tsangpo Suture Zone are key to reconstructing the evolution of the Tibetan orogen. Here, I present data on the age, provenance, and paleoelevation of the Liuqu Conglomerate, a continental deposit exposed within this suture zone. Paleocurrent analysis indicates that sediment was shed northward in the paleo-Liuqu basin. However, detrital U-Pb zircon age spectra and clast counts indicate that the Liuqu Conglomerate contains both Asian and Indian detritus. Analysis of paleosols and carbon isotopic composition of paleosol carbonates provide constraints on the paleoaltimetry of the Liuqu Conglomerate. New zircon U-Pb and biotite 40Ar/39Ar analyses are used to assign a preliminary, early Miocene age to this formation. More analyses are required to confirm this age determination. The Liuqu Conglomerate was deposited in alluvial fans and other coarse-grained fluvial deposystems. The Liuqu basin formed between ophiolitic mélanges (to the south) and uplifted Cretaceous forearc deposits (to the north) along the central, 1000 km long segment of the Yarlung-Tsangpo suture zone in southern Tibet. Sedimentological analysis shows the unit to be composed of mixed fluvial and sediment-gravity flow lithofacies assemblages, locally punctuated by mature, clay-rich paleosols. Structural and architectural analyses indicate that the Liuqu Conglomerate was deposited in a contractional setting. Paleocurrent and provenance data demonstrate that sediment was transported northward from the hanging wall of a Great Counter Thrust related thrust system that forms the southern limit of Liuqu outcrops. Detrital zircon U-Pb ages cluster around 80-110 Ma (ɛHf = -23.5 - 14.6), 120-135 Ma (ɛHf = -12.6 - 13.1), 500-600 Ma (ɛHf = -26 - 3.4), and 1100-1200 Ma (ɛHf = -27.6 - 2.9), requiring input from both Asian and Indian sources. Two detrital zircon U-Pb ages obtained from the Liuqu Conglomerate are ca. 18 Ma and provide a preliminary maximum depositional

  5. Surface-geophysical characterization of ground-water systems of the Caloosahatchee River basin, southern Florida

    USGS Publications Warehouse

    Cunningham, Kevin J.; Locker, Stanley D.; Hine, Albert C.; Bukry, David; Barron, John A.; Guertin, Laura A.

    2001-01-01

    The Caloosahatchee River Basin, located in southwestern Florida, includes about 1,200 square miles of land. The Caloosahatchee River receives water from Lake Okeechobee, runoff from the watershed, and seepage from the underlying ground-water systems; the river loses water through drainage to the Gulf of Mexico and withdrawals for public-water supply and agricultural and natural needs. Water-use demands in the Caloosahatchee River Basin have increased dramatically, and the Caloosahatchee could be further stressed if river water is used to accommodate restoration of the Everglades. Water managers and planners need to know how much water will be used within the river basin and how much water is contributed by Lake Okeechobee, runoff, and ground water. In this study, marine seismic-reflection and ground-penetrating radar techniques were used as a means to evaluate the potential for flow between the river and ground-water systems. Seven test coreholes were drilled to calibrate lithostratigraphic units, their stratal geometries, and estimated hydraulic conductivities to surface-geophysical profiles. A continuous marine seismic-reflection survey was conducted over the entire length of the Caloosahatchee River and extending into San Carlos Bay. Lithostratigraphic units that intersect the river bottom and their characteristic stratal geometries were identified. Results show that subhorizontal reflections assigned to the Tamiami Formation intersect the river bottom between Moore Haven and about 9 miles westward. Oblique and sigmoidal progradational reflections assigned to the upper Peace River Formation probably crop out at the floor of the river in the Ortona area between the western side of Lake Hicpochee and La Belle. These reflections image a regional-scale progradational deltaic depositional system containing quartz sands with low to moderate estimated hydraulic conductivities. In an approximate 6-mile length of the river between La Belle and Franklin Lock, deeper

  6. Modelling the hydrodynamic and morphosedimentary response of an beach-headland system (Algarve, Southern Portugal)

    NASA Astrophysics Data System (ADS)

    Horta, João; Oliveira, Sónia; Moura, Delminda

    2015-04-01

    Future behaviour of beaches within a headland-beach system is of fundamental interest on coastal evolution since they act as a buffer between the waves' attack and the cliffs backing them. The beaches at the cliffs' foot anchored between headlands are space-limited environments to morphosedimentary processes. Additionally, headlands and shore platforms are natural barriers to the alongshore drift. Several attempts to develop numerical expressions to characterize the stability of headland-beach systems have been made based mainly on linear parameters. However, in the sandy areas occur volumetric variations of greater magnitude that changes in the shoreline position in a tidal cycle. This work aims to quantify