(Table 1) Lipid and organochlorine content in blood of common eiders (Somateria mollissima) in Svalbard

Female common eiders (Somateria mollissima) starve during the nesting stage and may lose 30-45% of their initial body mass, mostly through lipid mobilization. In this study, the effects of fasting on the blood concentrations of three lipid-soluble organochlorines (OCs: polychlorinated biphenyl [PCB]-153; 1-dichloro-2,2-bis (p-chlorophenyl) ethylene [p,p'-DDE]; and hexachlorobenzene [HCB]) were examined in eiders breeding in the high Arctic. Blood samples were taken from females (n = 47) at day 5 and day 20 of the incubation period. The mean wet weight concentrations of PCB-153 and p,p'-DDE increased strongly between day 5 and day 20 (3.6 and 8.2-fold, respectively), while HCB increased less (1.7-fold). There was a strong negative association between daily increase in PCB-153 and clutch size, and a weaker relationship for p,p'-DDE, suggesting that maternal transfer to the eggs is a significant pathway of elimination of OCs in eiders. Moreover, poor body condition (body mass controlled for body size) late in the incubation period was associated with strong daily increase of both p,p'-DDE and PCB-153, which may suggest that the release of these compounds increases when lipid reserves become depleted. For HCB, the increase was mainly associated with increase in blood lipid concentrations, and weakly to the amount of burned lipids. The causes for the differences between the compounds are, however, poorly understood. Although the absolute levels of OCs in eiders were relatively low, their rapid build-up during incubation is worrying as it coincides with poor body condition and weakened immune systems.

(Table) Bacterial counts and Fe, Mn and SO4 content in sediments and pore waters of two cores from Lake Baikal

Sediments at the bottom of Lake Baikal are mostly oxidized at their surface, and the oxidized sedimentary deposits are enriched in Fe and Mn hydroxides. The thickness of the oxidized zone of the pelagic sediments averages at 5 cm and locally reaches 10-15, occasionally exceeding 20 cm. Both the thickness of the oxidized layer and the degree of its enrichment in iron and manganese hydroxides are controlled by the depth to which oxygen can penetrate into the sedimentary deposits, which is, in turn, closely related to the sedimentation conditions in the lake (which broadly vary). The sedimentation rate far off the shores of Lake Baikal ranges from <0.02 mm/year to 1.5 mm/year, and the content of organic matter buried in the sediments varies from 0.1 to >4%. The variability of the sedimentation process makes Lake Baikal very convenient to study its diagenetic processes related to redox reactions in sediments, first of all, processes responsible for the redistribution of Fe and Mn compounds. Although the diagenetic enrichment of Fe and Ni in bottom sediments is known to be of biogenic character, very scarce information is available so far on the microorganisms involved in the redistribution of these elements in sediments in Lake Baikal, which lately led us to explore this issue in detail. Our research was centered on the role played by the microbial community in the diagenetic transformations of Fe and Mn with reference to sedimentation conditions in Lake Baikal.

Age determination and carbonate content of sediment core KH-79-3_L3

Laminated sediments deposited under anoxic bottom waters in the Japan Sea during the last glacial maximum (LGM) contain extremely well preserved calcareous microfossils and eolian carbonates. The radiocarbon age-difference between bulk sediment and monospecific planktonic foraminifera in discrete laminae from a core in the southern Japan Sea implies that ~40% of the total carbonates in the sediments at the LGM are of eolian origin. Extrapolation of this result yields a rate of supply of eolian carbonates of ~2800 tons/d to the entire Japan Sea during the LGM. The climatic significance of this flux potentially lies in its broader geographic extension, particularly in the interaction of the carbonate-bearing dust with shallow, corrosive North Pacific waters and with rain in the atmosphere. By increasing the alkalinity of such waters and by enhancing the biological pump the dust flux could have increased CO2 absorption by both the ocean and rain during the LGM.

H, O, Sr, and Nd isotope ratios and water, Rb, Sr, Sm, and Nd content of ODP Hole 116-717C and 116-718C samples (Table 2)

Mineralogical and H, O, Sr, and Nd isotope compositions have been analyzed on a set of representative samples from the 17-m.y. section in ODP Leg 116 Holes 717C and 718C. Based on the mineralogical composition of the fraction <2 µm together with the lithogenic-biogenic composition of the fraction >63 µm, the whole section can be subdivided into three major periods of sedimentation. Between 17.1 and 6 m.y., and between 0.8 m.y. to present, the sediments are characterized by sandy and silty turbiditic inputs with a high proportion of minerals derived from a gneissic source without alteration. In the fraction <2 µm, illite and chlorite are dominant over smectite and kaolinite. The granulometric fraction >63 µm contains quartz, muscovite, biotite, chlorite, and feldspars. The 6-to 0.8-m.y. period is represented by an alternation of sandy/silty horizons, muds, and calcareous muds rich in smectite, and kaolinite (50% to 85% of the fraction <2 µm) and bioclastic material. The presence of smectite and kaolinite, as well as the 18O/16O and the 87Sr/86Sr ratios of the fraction <2 µm, imply an evolution in a soil environment and exchanges with meteoric ground water. The ranges of isotopic compositions are limited throughout the section: d18O quartz = 11.7 to 13.3 per mil, 87Sr/86Sr = 0.733 to 0.760 and epsilon-Nd (0) = -17.4 to -13.8. These values are within those of the High Himalaya Crystalline series, and they are considered to reflect this source region. The data imply that, since 17 Ma, this formation has supplied the major part of the eroded material.