Isotopic analysis of core gases at DSDP Leg 84 Holes

Methane carbon-isotopic compositions (d13C values relative to the PDB standard) at Sites 565, 566, 567, and 569 were lighter (enriched in 12C) than -60 per mil, indicating a biogenic origin. In the deeper sections at Sites 568 and 570, d13C values were heavier, approaching -40 per mil, and therefore suggest a thermogenic source. A significant thermogenic source was discounted, however, because the carbon dioxide d13C values in these sections were also anomalously heavy, suggesting that the methane may have formed biogenically by reduction of the heavy carbon dioxide. d13C values of ethane and higher hydrocarbons were measured in several sections from Sites 566 and 570 that contained sufficient C2-C4 hydrocarbon concentrations. Ethane values in six sections (245-395 m sub-bottom) from Site 570 were fairly uniform, ranging from -24 to -26 per mil. These values are among the heaviest ethane values reported for natural gases. The isobutane/ n-butane and isopentane/n-pentane ratios of the core gases suggested that the C2-C5 hydrocarbons are thermally produced by low-temperature chemical diagenesis of indigenous organic matter. This process apparently generates isotopically heavy C2-C5 hydrocarbons. High gas concentrations in the serpentinite basement rocks at Sites 566 and 570 appear to have resulted from migrated biogenic methane gas containing small amounts of immature C2-C5 hydrocarbons.

(Table 1) Lipid content and organohalogen contaminant concentration in plasma of incubating glaucous gulls (Larus hyperboreus) from Bjørnøya, Norwegian Arctic in 2006

The factors influencing prolactin (PRL) variation in birds and in wildlife in general have rarely been investigated with respect to the physiological impacts of exposure to environmental contaminants. We investigated the associations between circulating baseline PRL levels and concentrations of eight persistent organohalogen contaminant (OHC) classes (i.e., major organochlorines and brominated flame retardants, and associated metabolic products) in blood (plasma) of free-ranging glaucous gulls (Larus hyperboreus), a top predator in the Norwegian Arctic, engaged in the process of incubation. We further examined whether plasma OHC concentrations were associated with the variation of PRL in glaucous gulls exposed to a standardized capture/restraint protocol. Plasma OHC concentrations in male glaucous gulls were 2-to 3-fold higher relative to females. Baseline PRL levels tended to be higher in females compared to males, although not significantly (p = 0.20). In both males and females, the 30-min capture/restraint protocol led on average to a 26% decrease in PRL levels, which resulted in a rate of PRL decrease of 0.76 ng/mL/min. The baseline PRL levels and the rate of decrease in PRL levels tended to vary negatively with plasma OHC concentrations in males, but not in females, although several of these associations did not adhere with the criterion of significance (alpha = 0.05). Present results suggest that in highly OHC-exposed male glaucous gulls, the control of PRL release may be affected by the direct or indirect modulating actions of OHCs and/or their metabolically derived products. We conclude that potentially OHC-mediated impact on PRL secretion in glaucous gulls (males) may be a contributing factor to the adverse effects observed on the reproductive behavior, development and population size of glaucous gulls breeding in the Norwegian Arctic.

Abundance and chemical and mineral compositions of nodules from the Pacific Ocean

The monograph highlights extensive materials collected during expeditions of P.P. Shirshov Institute of Oceanology. We consider facial conditions of nodule formation, regularities of their distribution, stratigraphic position, petrography, mineral composition, textures, geochemistry of nodules and hosting sediments. Origin of iron-manganese nodules in the Pacific Ocean is considered as well.