Recursos de colección

PANGAEA - Publishing Network for Geoscientific & Environmental Data (830.700 recursos)

The information system PANGAEA is operated as an Open Access library aimed at archiving, publishing and distributing georeferenced data from earth system research. The system guarantees long-term availability of its content through a commitment of the operating institutions.

Datasets of project "Atlantic Data Base for Exchange Processes at the Deep Sea Floor"

Mostrando recursos 1 - 20 de 1.752

  1. Oxygen consumption in Arctic sediments

    Hulth, Stefan; Blackburn, T H; Hall, Per
    Total sediment oxygen consumption rates (TSOC or Jtot), measured during sediment-water incubations, and sediment oxygen microdistributions were studied at 16 stations in the Arctic Ocean (Svalbard area). The oxygen consumption rates ranged between 1.85 and 11.2 mmol m**-2 d**-1, and oxygen penetrated from 5.0 to >59 mm into the investigated sediments. Measured TSOC exceeded the calculated diffusive oxygen fluxes (Jdiff) by 1.1-4.8 times. Diffusive fluxes across the sediment-water interface were calculated using the whole measured microprofiles, rather than the linear oxygen gradient in the top sediment layer. The lack of a significant correlation between found abundances of bioirrigating meiofauna and...

  2. Biogeochemistry on 396 surface sediment profiles from the Atlantic Ocean

    Pfannkuche, Olaf

  3. Activity and biomass of small benthic biota in the central Arctic Ocean

    Soltwedel, Thomas; Schewe, Ingo
    Sediment samples collected during the expedition "Arctic Ocean '96" with the Swedish ice-breaker ODEN were investigated to estimate for the first time heterotrophic activity and total microbial biomass (size range from bacteria to small metazoans) from the perennially ice-covered central Arctic Ocean. Benthic activities and biomass were evaluated analysing a series of biogenic sediment compounds (i.e. bacterial exoenzymes, total adenylates, DNA, phospholipids, particulate proteins). In contrast to the very time-consuming sorting, enumeration and weight determination, analyses of biochemical sediment parameters may represent a useful method for obtaining rapid information on the ecological situation in a given benthic system. Bacterial cell...

  4. (Table 2) Biogenic sediment compounds and bacterial abundances of surface sediments in the central Arctic Ocean

    Soltwedel, Thomas; Schewe, Ingo

  5. Pigments of sediment cores of the Northwest European Continental Margin

    Pfannkuche, Olaf; Soltwedel, Thomas
    In the context of the European OMEX Programme this investigation focused on gradients in the biomass and activity of the small benthic size spectrum along a transect across the Goban Spur from the outer Celtic Sea into Porcupine Abyssal Plain. The effects of food pulses (seasonal, episodic) on this part of the benthic size spectrum were investigated. Sediments sampled during eight expeditions at different seasons covering a range from 200 m to 4800 m water depth were assayed with biochemical bulk measurements: determinations of chloroplastic pigment equivalents (CPE), the sum of chlorophyll a and its breakdown products, provide information concerning...

  6. Pigment distribution in surface sediments of the North Atlantic Ocean

    Pfannkuche, Olaf; Boetius, Antje; Lundgreen, Ulrich; Lochte, Karin; Thiel, Hjalmar
    In an extended deep-sea study the response of the benthic community to seasonally varying sedimentation rates of organic matter were investigated at a fixed abyssal site in the NE Atlantic (BIOTRANS station or JGOFS station L2 at 47°N-20°W, water depth >4500 m) on four legs of METEOR expedition 21 between March and August 1992. The vertical flux at 3500 m depth and temporal variations in the chloroplastic pigment concentration, a measure of phytodetritus deposition, and of total adenylates and total phospholipids, measures of benthic biomass, and of activity of hydrolytic enzymes were observed. The flux patterns in moored sediment traps...

  7. Carbon and nitrogen content of marine pore waters

    Martin, William R; McCorkle, Daniel C
    We have developed sampling methods and an analytical system to determine the concentration of dissolved organic C (DOC) in marine pore waters. Our analytical approach is a modification of recently developed high-temperature, Pt-catalyzed oxidation methods; it uses Chromatographic trapping of the DOC-derived CO2 followed by reduction to CH4 and flame ionization detection. Sampling experiments with nearshore sediments indicate that pore-water separation by whole-core squeezing causes artificially elevated DOC concentrations, while pore-water recovery by sectioning and centrifugation does not appear to introduce DOC artifacts. Results from a set of northwestern Atlantic continental slope cores suggest that net DOC production accounts for...

  8. Biomass and bioturbation in surface sediments of the Arctic Ocean

    Clough, Lisa; Ambrose jr, William G; Cochran, James R; Barnes, C; Renaud, Paul E; Aller, Robert C.
    Little is known about the benthic communities of the Arctic Ocean's slope and abyssal plains. Here we report on benthic data collected from box cores along a transect from Alaska to the Barents Abyssal Plain during the Arctic Ocean Section of 1994. We determined: (1) density and biomass of the polychaetes, foraminifera and total infauna; (2) concentrations of potential sources of food (pigment concentration and percent organic carbon) in the sediments; (3) surficial particle mixing depths and rates using downcore 210Pb profiles; and (4) surficial porewater irrigation using NaBr as an inert tracer. Metazoan density and biomass vary by almost...

  9. Sediment metabolism in samples off Northwest Africa

    Christensen, John P; Packard, Ted T
    Sediments off northwest Africa were assayed for activities of the respiratory electron transport system (ETS) and for primary amino nitrogen. ETS activities were used to compute respiratory oxygen consuption, carbon oxidation, and nitrate reduction rates. Activities were correlated with depth of the water column, and their longshore distribution resembled that of euphotic zone phytoplankton productivity. Protein concentrations were closely correlated with ETS activities. Carbon biomass was calculated from protein and compared with other computed values. The carbon oxidation rate accounted for 13 % of the region's primary production.

  10. Respiration and dissolution in sediments of the western Atlantic

    Hales, Burke; Emerson, Steven R; Archer, David E
    We present in situ microelectrode measurements of sediment formation factor and porewater oxygen and pH from six stations in the North Atlantic varying in depth from 2159 to 5380 m. A numerical model of the oxygen data indicates that fluxes of oxygen to the sediments are as much as an order of magnitude higher than benthic chamber flux measurements previously reported in the same area. Model results require dissolution driven by metabolic CO2 production within the sediments to explain the pH data; even at the station with the most undersaturated bottom waters >60% of the calcite dissolution occurs in response...

  11. Carbon and Lead chemistry of sediments from the Middle Atlantic Bight

    Anderson, Robert F; Rowe, Gilbert T; Kemp, P F; Trumbore, S; Biscaye, Pierre Eginton
    A mass budget was constructed for organic carbon on the upper slope of the Middle Atlantic Bight, a region thought to serve as a depocenter for fine-grained material exported from the adjacent shelf. Various components of the budget are internally consistent, and observed differences can be attributed to natural spatial variability or to the different time scales over which measurements were made. The flux of organic carbon to the sediments in the core of the depocenter zone, at a water depth of 1000 m, was measured with sediment traps to be 65 mg C m**-2 day**-1, of which 6-24 mg...

  12. Organic carbon flux through the benthic community in the temperate abyssal Northeast Atlantic

    Pfannkuche, Olaf
    In order to assess the carbon flux through the deep-sea benthic boundary layer, sediment community oxygen consumption (SCOC) was measured in different months and years at the BIOTRANS area in the abyssal northeastern Atlantic. SCOC varied seasonally with a maximum in July/August. Evidence is given for a direct coupling between a substantial sedimentation of phytodetritus and the seasonal increase in SCOC. Rapid colonization, growth and decomposition rates indicate that the deep-sea benthic microbial and protozoan biota can react quickly to substantial falls of particulate organic matter. They seem to be the most important groups to generate seasonal changes in deep-sea...

  13. TOC, CaCO3, porosity, Lead 210 of sediment core A_EN187-BC9

    Anderson, Robert F; Rowe, Gilbert T; Kemp, P F; Trumbore, S; Biscaye, Pierre Eginton

  14. TOC, CaCO3, porosity, Lead 210 of sediment core A_EN187-BC8

    Anderson, Robert F; Rowe, Gilbert T; Kemp, P F; Trumbore, S; Biscaye, Pierre Eginton

  15. TOC, CaCO3, porosity, Lead 210 of sediment core A_EN187-BC6

    Anderson, Robert F; Rowe, Gilbert T; Kemp, P F; Trumbore, S; Biscaye, Pierre Eginton

  16. TOC, CaCO3, porosity, Lead 210 of sediment core A_EN187-BC5

    Anderson, Robert F; Rowe, Gilbert T; Kemp, P F; Trumbore, S; Biscaye, Pierre Eginton

  17. TOC, CaCO3, porosity, Lead 210 of sediment core A_EN187-BC4

    Anderson, Robert F; Rowe, Gilbert T; Kemp, P F; Trumbore, S; Biscaye, Pierre Eginton

  18. TOC, CaCO3, porosity, Lead 210 of sediment core A_EN187-BC3

    Anderson, Robert F; Rowe, Gilbert T; Kemp, P F; Trumbore, S; Biscaye, Pierre Eginton

  19. TOC, CaCO3, porosity, Lead 210 of sediment core A_EN187-BC1

    Anderson, Robert F; Rowe, Gilbert T; Kemp, P F; Trumbore, S; Biscaye, Pierre Eginton

  20. TOC, CaCO3, porosity, Lead 210 of sediment core A_EN187-BC11

    Anderson, Robert F; Rowe, Gilbert T; Kemp, P F; Trumbore, S; Biscaye, Pierre Eginton

Aviso de cookies: Usamos cookies propias y de terceros para mejorar nuestros servicios, para análisis estadístico y para mostrarle publicidad. Si continua navegando consideramos que acepta su uso en los términos establecidos en la Política de cookies.