Organic geochemical studies of DSDP Leg 64 Holes

Twenty-six core samples from Leg 64, Holes 474, 474A, 477, 478, 479, and 481A in the Gulf of California, were provided by the Joint Oceanographic Institutions for Deep Earth Sampling (JOIDES) Advisory Panel on Organic Geochemistry for analysis. The high heat flow characteristic of the basin provides an opportunity to study the effect of temperature on the diagenesis of organic matter. The contents and carbon isotope compositions of the organic matter and bitumen fractions of different polarity, isoprenoid and normal alkane distributions, and the nature of tetrapyrrole pigments were studied. Relative contents of hydrocarbons and bitumens depend on the thermal history of the deposits. Among other criteria, the nature and content of tetrapyrrole pigments appear to be most sensitive to thermal stress. Whereas only chlorins are present in the immature samples, porphyrins, including VO-porphyrins, appear in the thermally altered deposits, despite the shallow burial depth. Alkane distributions in thermally changed samples are characterized by low values of phytane to 2-C18 ratios and an odd/even carbon preference index close to unity. The thermally altered samples show unusual carbon isotope distributions of the bitumen fractions. The data also provide some evidence concerning the source of the organic matter and the degree of diagenesis.

Global distributions of diazotrophs Gamma-A nifH genes abundance - Depth integrated values computed from a collection of source datasets - Contribution to the MAREDAT World Ocean Atlas of Plankton Functional Types

The MAREDAT atlas covers 11 types of plankton, ranging in size from bacteria to jellyfish. Together, these plankton groups determine the health and productivity of the global ocean and play a vital role in the global carbon cycle. Working within a uniform and consistent spatial and depth grid (map) of the global ocean, the researchers compiled thousands and tens of thousands of data points to identify regions of plankton abundance and scarcity as well as areas of data abundance and scarcity. At many of the grid points, the MAREDAT team accomplished the difficult conversion from abundance (numbers of organisms) to biomass (carbon mass of organisms). The MAREDAT atlas provides an unprecedented global data set for ecological and biochemical analysis and modeling as well as a clear mandate for compiling additional existing data and for focusing future data gathering efforts on key groups in key areas of the ocean. The present data set presents depth integrated values of diazotrophs Gamma-A nifH genes abundance, computed from a collection of source data sets.

Global distributions of diazotrophs abundance and biomass - Depth integrated values computed from a collection of source datasets - Contribution to the MAREDAT World Ocean Atlas of Plankton Functional Types

The MAREDAT atlas covers 11 types of plankton, ranging in size from bacteria to jellyfish. Together, these plankton groups determine the health and productivity of the global ocean and play a vital role in the global carbon cycle. Working within a uniform and consistent spatial and depth grid (map) of the global ocean, the researchers compiled thousands and tens of thousands of data points to identify regions of plankton abundance and scarcity as well as areas of data abundance and scarcity. At many of the grid points, the MAREDAT team accomplished the difficult conversion from abundance (numbers of organisms) to biomass (carbon mass of organisms). The MAREDAT atlas provides an unprecedented global data set for ecological and biochemical analysis and modeling as well as a clear mandate for compiling additional existing data and for focusing future data gathering efforts on key groups in key areas of the ocean. The present data set presents depth integrated values of diazotrophs abundance and biomass, computed from a collection of source data sets.

Global distributions of diazotrophs nitrogen fixation rates - Depth integrated values computed from a collection of source datasets - Contribution to the MAREDAT World Ocean Atlas of Plankton Functional Types

The MAREDAT atlas covers 11 types of plankton, ranging in size from bacteria to jellyfish. Together, these plankton groups determine the health and productivity of the global ocean and play a vital role in the global carbon cycle. Working within a uniform and consistent spatial and depth grid (map) of the global ocean, the researchers compiled thousands and tens of thousands of data points to identify regions of plankton abundance and scarcity as well as areas of data abundance and scarcity. At many of the grid points, the MAREDAT team accomplished the difficult conversion from abundance (numbers of organisms) to biomass (carbon mass of organisms). The MAREDAT atlas provides an unprecedented global data set for ecological and biochemical analysis and modeling as well as a clear mandate for compiling additional existing data and for focusing future data gathering efforts on key groups in key areas of the ocean. The present data set presents depth integrated values of diazotrophs nitrogen fixation rates, computed from a collection of source data sets.

Th and U isotopes, dose rates and ages of marine shells and sediment of core GIK14350, north Germany

The ESR dating method was applied to marine shells taken from a sediment core from Dagebüll, Schleswig-Holstein. Four samples from two different depths of the core (17.5 m and 25-26 m), separated by a 2.76 meter thick clay layer (Turritella Clay), yielded identical ages within the limits of error. They indicated an assignment to the oxygen isotope stage 5, thus confirming the stratigraphic age. In addition, the ESR-ages confirm the interpretation of Lomitschka et al. (1997, doi:10.2312/meyniana.1997.49.85), that the Th/U-ages of shells below the clay layer are reliable, whereas shells located above the clay layer, which were strongly influenced by percolating groundwaters of an open system, yielded falsified Th/U-ages.