(Table 1) Maceral composition and organic carbon chemistry of ODP Leg 104 samples

The Cenozoic sediments sampled in ODP Leg 104 on the Vøring Plateau show a distinct variability of the total organic carbon content (TOC) and the accumulation rates of TOC. Based on the geochemical and organic-petrographic characterization of the sedimentary organic matter (OM), the allochthonous and autochthonous proportion of the OM could be quantified. The results clearly demonstrate that high TOC percentages and TOC accumulation rates in Cenozoic sediment sections display a generally high input of allochthonous organic matter. Oxidized and partly well-rounded organic particles built up the main portion of OM within the Miocene, TOC-rich sediments. The most probable source of this oxidized OM are reworked sediments from the Scandinavian shelf. Changes in the input of these organic particles are to some degree correlative with sea-level changes. The Cenozoic accumulation of autochthonous OM is low and does not reveal a clear variation during the Miocene and early Pliocene. In spite of a high accumulation rate of biogenic opal during the Early Miocene, the accumulation rate of autochthonous TOC is low. The autochthonous particle assemblage is dominated by relatively inert OM, like dinoflagellate cysts. This points to an intensive biological and/or early diagenetic degradation of the marine OM under well oxidized bottom water conditions during the last 23 Myr. Nevertheless, a continuation of marine OM degradation during later stages of diagenesis cannot be excluded. A prominent dominance of allochthonous OM over autochthonous is documented with the beginning of the Pliocene. At 2.45 Ma the episodic occurrence of ice-rafted, thermally mature OM reflects the onset of the glacial erosion of Mesozoic, coal and black shale bearing sediments on the Scandinavian and Barents Sea shelves. The first occurrence of these, in view of the actual burial depth, thermally overmature OM particles is, therefore, a marker for the beginning of the strong Scandinavian glaciation and the advance of the glacial front toward the shelves.

Water chemistry, and biological traits and mercury content of Salvelinus alpinus and S. namaycush in Laflamme and Pingualuit lake

Pingualuk Lake fills a deep crater in the Parc National des Pingualuit on the Ungava Peninsula (Nunavik, Canada) and is isolated from nearby surface waters. The main objectives of this study were to determine and compare the concentrations of two atmospherically derived contaminants, mercury and perfluorinated chemicals (PFCs), in the lake water column and fish of Pingualuk Lake and to assess the physical and biological factors influencing contaminant concentrations. Mercury concentrations in arctic char muscle tissue were comparable to those of char in other Arctic lakes, while the total amount of PFCs was below reported levels for remote lakes in the Arctic and elsewhere. Stable isotope and stomach content analyses were made to investigate the feeding ecology of the Pingualuk Lake arctic char population and indicated the possibility of multiple feeding groups. Genetics characteristics (MH and mtDNA) of fish from Pingualuk Lake revealed that this population is likely distinct from that of nearby Laflamme Lake. However, both arctic char populations exhibit differential variation of their allele families. Physical characteristics determined for Lake Pingualuk revealed that the water column was inversely stratified beneath the ice and extremely transparent to visible and ultraviolet radiation. The highest mercury concentrations (3- 6 pg/mL THg) occurred just beneath the ice surface in each lake. Pingualuk Lake, given its near pristine state and exceptional limnological features, may serve as a most valuable reference ecosystem for monitoring environmental stressors, such as contaminants, in the Arctic.

Studies of the microbial diversity on analyzed samples from from Peru Margin, Equatorial Pacific, Hydrate Ridge, and Juan de Fuca Ridge

Marine sediments harbor an enormous quantity of microorganisms, including a multitude of novel species. The habitable zone of the marine sediment column begins at the sediment-water interface and probably extends to depths of several thousands of meters. Studies of the microbial diversity in this ecosystem have mostly relied on molecular biological techniques. We used a complementary method - analysis of intact polar membrane lipids - to characterize the in-situ microbial community in sediments covering a wide range of environmental conditions from Peru Margin, Equatorial Pacific, Hydrate Ridge, and Juan de Fuca Ridge. Bacterial and eukaryotic phospholipids were only detected in surface sediments from the Peru Margin. In contrast, deeply buried sediments, independent of their geographic location, were dominated by archaeal diether and tetraether lipids with various polar head groups and core lipids. We compared ring distributions of archaeal tetraether lipids derived from polar glycosidic precursors with those that are present as core lipids. The distributions of these related compound pools were distinct, suggestive of different archaeal sources, i.e., the polar compounds derive from sedimentary communities and the core lipids are fossil remnants from planktonic communities with possible admixtures of decayed sedimentary archaea. This in-situ production of distinct archaeal lipid populations potentially affects applications of the TEX86 paleotemperature proxy as demonstrated by offsets in reconstructed temperatures between both pools. We evaluated how varying cell and lipid stabilities will influence the sedimentary pool by using a box-model. The results are consistent with (i) a requirement of continuous inputs of freshly synthesized lipids in subsurface sediments for explaining the observed distribution of intact polar lipids, and (ii) decreasing lipid inputs with increasing burial depth.

(Table 3) Concentrations of polybrominated diphenyl ether and congeners in blubber samples from whales, seals and porpoises between 1986-2009

A selection of PBDE congeners was analyzed in pooled blubber samples of pilot whale (Globicephala melas), ringed seal (Phoca hispida), minke whale (Balaenoptera acutorostrata), fin whale (Balaenoptera physalus), harbor porpoise (Phocoena phocoena), hooded seal (Cystophora cristata) and Atlantic white-sided dolphin (Lagenorhynchus acutus), covering a time period of more than 20 years (1986-2009). The analytes were extracted and cleaned-up using open column extraction and multi-layer silica gel column chromatography, and the analysis was performed on a GC-MS system operating in the NCI mode. The highest PBDE levels were found in the toothed whale species pilot whale and white-sided dolphin, and the lowest levels in fin whales and ringed seals. One-sided analyses of variance (ANOVA) followed by Tukey comparisons of means were applied to test for differences between years and sampling areas. Due to inter-year sampling variability, only general comparisons of PBDE concentrations between different sampling areas could be made. Differences in PBDE concentrations between three sampling periods, from 1986 to 2007, were evaluated in samples of pilot whales, ringed seals, white-sided dolphins and hooded seals. The highest PBDE levels were found in samples from the late 1990s or beginning of 2000, possibly reflecting the increase in the global production of technical PBDE mixtures in the 1990s. The levels of BDE #153 and #154 increased relative to the total PBDE concentration in some of the species in recent years, which may indicate an increased relative exposure to higher brominated congeners. In order to assess the effect of measures taken in legally binding international agreements, it is important to continuously monitor POPs such as PBDEs in sub-Arctic and Arctic environments.

Organic carbon and calcium carbonate concentrations of K/T boundary samples from southern Tethyan margin location (Table 1)

Regional consequences of the biotic extinctions and of the changes in biological productivity that occurred at the time of the Cretaceous/Tertiary (K/T) boundary were investigated by comparison of organic matter in sediments from three southern Tethyan margin locations. Organic matter characterization comprised Rock-Eval pyrolysis and organic carbon measurements. Low concentrations of organic matter precluded additional detailed determinations. At all three locations, the organic matter has been microbially reworked and evidently was deposited in oxygenated marine environments.