Chemical composition of basalts from coarse debris of the Kara Sea bottom sediments

Study of basaltic debris from the Kara Sea bottom has shown its similarity to traps of the Eastern Siberia in mineralogy, structures and chemical composition. In comparison with oceanic tholeiites, the source of traps and Kara Sea basin basaltic melts was enriched in REE and some other incompatible elements. K-Ar dating of two samples of supposed autochtonous location from the eastern part of the Kara Sea basin has shown 209 and 218 Ma - younger than traps (247-248 Ma). Origin of Siberian traps used to connect with action of the mantle plume (Iceland plume, according to geodinamic reconstruction). Our new age data may be interpreted as an evidence of the Siberian plate moving over the head of plume.

Contiunous surface water uncorrected and quench-corrected active fluorescence and derived chlorophyll a concentration using calibration by HPLC pigments during POLARSTERN cruise ANT-XXV/1

The relationship between phytoplankton assemblages and the associated optical properties of the water body is important for the further development of algorithms for large-scale remote sensing of phytoplankton biomass and the identification of phytoplankton functional types (PFTs), which are often representative for different biogeochemical export scenarios. Optical in-situ measurements aid in the identification of phytoplankton groups with differing pigment compositions and are widely used to validate remote sensing data. In this study we present results from an interdisciplinary cruise aboard the RV Polarstern along a north-to-south transect in the eastern Atlantic Ocean in November 2008. Phytoplankton community composition was identified using a broad set of in-situ measurements. Water samples from the surface and the depth of maximum chlorophyll concentration were analyzed by high performance liquid chromatography (HPLC), flow cytometry, spectrophotometry and microscopy. Simultaneously, the above- and underwater light field was measured by a set of high spectral resolution (hyperspectral) radiometers. An unsupervised cluster algorithm applied to the measured parameters allowed us to define bio-optical provinces, which we compared to ecological provinces proposed elsewhere in the literature. As could be expected, picophytoplankton was responsible for most of the variability of PFTs in the eastern Atlantic Ocean. Our bio-optical clusters agreed well with established provinces and thus can be used to classify areas of similar biogeography. This method has the potential to become an automated approach where satellite data could be used to identify shifting boundaries of established ecological provinces or to track exceptions from the rule to improve our understanding of the biogeochemical cycles in the ocean.

Composition and accumulation rates of bottom sediments from Core ASV16-1372, Voring Plateau

Based on sedimentological, mineralogical, geochemical, and micropaleontological data on comprehensively investigated Core ASV16-1372, Late Pleistocene - Holocene sedimentation history is reconstructed for the Voring marginal plateau (continental margin of the Norwegian Sea). An age model constructed is based on correlation with several adjacent cores, for which AMS radiocarbon datings are available. Lithostratigraphic correlation made it possible to compare stratigraphic division of Core ASV16-1372 with other cores sampled on the Voring Plateau and the shelf and continental slope off Central Norway. It is concluded that compositional and structural features of bottom sediments are correlated with paleoclimatic and paleoceanographic changes, variations in provenances, as well as agents and pathways of sedimentary material transport.