123 resultados para 337.225
em Publishing Network for Geoscientific
Resumo:
A description is given of the taxa sorted out of the zooplanktion and mikronekton material of the 1st German Antarctic Expedition 1975/76 by the Kiel sorting center. The methods employed in the sorting center are describined in detail. Notes for further use of the material are also given.
Resumo:
Microbial life inhabits deeply buried marine sediments, but the extent of this vast ecosystem remains poorly constrained. Here we provide evidence for the existence of microbial communities in ~40° to 60°C sediment associated with lignite coal beds at ~1.5 to 2.5 km below the seafloor in the Pacific Ocean off Japan. Microbial methanogenesis was indicated by the isotopic compositions of methane and carbon dioxide, biomarkers, cultivation data, and gas compositions. Concentrations of indigenous microbial cells below 1.5 km ranged from <10 to ~10**4 cells cm**-3. Peak concentrations occurred in lignite layers, where communities differed markedly from shallower subseafloor communities and instead resembled organotrophic communities in forest soils. This suggests that terrigenous sediments retain indigenous community members tens of millions of years after burial in the seabed.
Resumo:
The modern depositional environment of the deep Norwegian-Greenland Sea is highly asymmetric in an E-W direction because of the hydrography of the surface water masses and because of the more or less permanent pack ice cover of the East Greenland Current regime along the Greenland continental margin. By means of sedimentation rates we have tried to investigate whether this hydrographic asymmetry influenced the sediment input to the Norwegian-Greenland Sea over the past 60 m.y. Sediment input can be quantified if thicknesses of sediment sections accumulated over known time intervals can be measured and if some of their physical properties have been determined. Sedimentation rates have been estimated for Tertiary and Quaternary times, and their temporal as well as their spatial changes are discussed. Basin structure and morphology exerted an important influence on sediment distribution. During the Early Tertiary major sediment source regions in the southern Barents Sea and to the north and west of Iceland could be identified; these source regions supplied the bulk of the sediment fill of the Norwegian-Greenland Sea. Since inception of a "glacial" type sedimentation major elements of the sea surface circulation seem to have controlled the sediment input into this polar and subpolar deep-sea basin.
Resumo:
At present time, there is a lack of knowledge on the interannual climate-related variability of zooplankton communities of the tropical Atlantic, central Mediterranean Sea, Caspian Sea, and Aral Sea, due to the absence of appropriate databases. In the mid latitudes, the North Atlantic Oscillation (NAO) is the dominant mode of atmospheric fluctuations over eastern North America, the northern Atlantic Ocean and Europe. Therefore, one of the issues that need to be addressed through data synthesis is the evaluation of interannual patterns in species abundance and species diversity over these regions in regard to the NAO. The database has been used to investigate the ecological role of the NAO in interannual variations of mesozooplankton abundance and biomass along the zonal array of the NAO influence. Basic approach to the proposed research involved: (1) development of co-operation between experts and data holders in Ukraine, Russia, Kazakhstan, Azerbaijan, UK, and USA to rescue and compile the oceanographic data sets and release them on CD-ROM, (2) organization and compilation of a database based on FSU cruises to the above regions, (3) analysis of the basin-scale interannual variability of the zooplankton species abundance, biomass, and species diversity.