(Table 1) Neutral and phenolic organohalogen compounds in blubber samples of ringed seals (Pusa hispida) from East Greenland

We report on the comparative bioaccumulation, biotransformation and/or biomagnification from East Greenland ringed seal (Pusa hispida) blubber to polar bear (Ursus maritimus) tissues (adipose, liver and brain) of various classes and congeners of persistent chlorinated and brominated contaminants and metabolic by-products: polychlorinated biphenyls (PCBs), chlordanes (CHLs), hydroxyl (OH-) and methylsulfonyl (MeSO2-) PCBs, polybrominated biphenyls (PBBs), OH-PBBs, polybrominated diphenyl ether (PBDE) and hexabromocyclododecane (HBCD) flame retardants and OH- and methoxyl (MeO-) PBDEs, 2,2-dichloro-bis(4-chlorophenyl)ethene (p,p'-DDE), 3-MeSO2-p,p'-DDE, pentachlorophenol (PCP) and 4-OH-heptachlorostyrene (4-OH-HpCS). We detected all of the investigated contaminants in ringed seal blubber with high frequency, the main diet of East Greenland bears, with the exception of OH-PCBs and 4-OH-HpCS, which indicated that these phenolic contaminants were likely of metabolic origin and formed in the bears from accumulated PCBs and octachlorostyrene (OCS), respectively, rather than being bioaccumulated from a seal blubber diet. For all of the detectable sum of classes or individual organohalogens, in general, the ringed seal to polar bear mean BMFs for SumPCBs, p,p'-DDE, SumCHLs, SumMeSO2-PCBs, 3-MeSO2-p,p'-DDE, PCP, SumPBDEs, total-(alpha)-HBCD, SumOH-PBDEs, SumMeO-PBDEs and SumOH-PBBs indicated that these organohalogens bioaccumulate, and in some cases there was tissue-specific biomagnification, e.g., BMFs for bear adipose and liver ranged from 2 to 570. The blood-brain barrier appeared to be effective in minimizing brain accumulation as BMFs were <= 1 in the brain, with the exception of SumOH-PBBs (mean BMF = 93±54). Unlike OH-PCB metabolites, OH-PBDEs in the bear tissues appeared to be mainly accumulated from the seal blubber rather than being metabolic formed from PBDEs in the bears. In vitro PBDE depletion assays using polar bear hepatic microsomes, wherein the rate of oxidative metabolism of PBDE congeners was very slow, supported the probability that accumulation from seals is the main source of OH-PBDEs in the bear tissues. Our findings demonstrated from ringed seal to polar bears that organohalogen biotransformation, bioaccumulation and/or biomagnification varied widely and depended on the contaminant in question. Our results show the increasing complexity of bioaccumulated and in some cases biomagnified, chlorinated and brominated contaminants and/or metabolites from the diet may be a contributing stress factor in the health of East Greenland polar bears.

Total organic carbon, delta13C, biomarker, gas compilations and hopanoids analysis from IODP Sites 307-U1317 and 307-U1318

During the Integrated Ocean Drilling Program (IODP) Expedition 307 for the first time a cold-water coral carbonate mound was drilled down through its base into the underlying sediments. In the current study, sample material from within and below Challenger Mound, located in the Belgica carbonate mound province in the Porcupine Basin offshore Ireland, was investigated for its distribution of microbial communities and gas composition using biogeochemical and geochemical approaches to elucidate the question on the initiation of carbonate mounds. Past and living microbial populations are lower in the mound section compared to the underlying sediments or sediments of an upslope reference site. A reason for this might be a reduced substrate feedstock, reflected by low total organic carbon (TOC) contents, in the once coral dominated mound sequence. In contrast, in the reference site a lithostratigraphic sequence with comparatively high TOC contents shows higher abundances of both past and present microbial communities, indicating favourable living conditions from time of sedimentation until today. Composition and isotopic values of gases below the mound base seem to point to a mixed gas of biogenic and thermogenic origin with a higher proportion of biogenic gas. Oil-derived hydrocarbons were not detected at the mound site. This suggests that at least in the investigated part of the mound base the upward flow of fossil hydrocarbons, being one hypothesis for the initiation of the formation of carbonate mounds, seems to be only of minor significance.

Biometry, stable isotopes and stomach contents of A. glacialis and B. saida from Northeast Greenland

Two gadoid fishes, Arctogadus glacialis and Boreogadus saida, often coexist (i.e. sympatric) in the fjords and shelf areas of the Arctic seas, where they likely share the same food resources. Diet composition from stomach contents, i.e. frequency of occurrence (FO) and Schoener's index (SI), and stable isotope signatures (d13C and d15N) in muscle of these sympatric gadoids were examined from two fjords in NE Greenland-Tyrolerfjord (TF, ~74°N, sill present) and Dove Bugt (DB, ~76°N, open). Twenty-three prey taxa and categories were identified and both gadoids ate mostly crustaceans. The SI values of 0.64-0.70 indicated possible resource competition, whereas FO differed significantly. A. glacialis fed mainly on the mysid Mysis oculata and other benthic-associated prey, whereas B. saida ate the copepod Metridia longa and other pelagic prey. Both diet and stable isotopes strongly suggest a spatial segregation in feeding habitat, with A. glacialis being associated with the benthic food web (mean d13C = -20.81 per mil, d15N = 14.92 per mil) and B. saida with the pelagic food web (mean d13C = -21.25 per mil, d15N = 13.64 per mil). The dietary differences and isotopic signals were highly significant in the secluded TF and less clear in the open DB, where prey and predators may be readily advected from adjacent areas with other trophic conditions. This is the first study on the trophic position of A. glacialis inferred from analyses of stable isotopes. The subtle interaction between the Arctic gadoids should be carefully monitored in the light of ocean warming and ongoing invasions of boreal fishes into the Arctic seas.