Concentrations of metals and POPs in liver tissue of wild sea bird chicks from the Norwegian arctic region

Lysosomal membrane stability, lipofuscin (LF), malondialdehyde (MDA), neutral lipid (NL) levels, as well as halogenated organic compounds (HOCs), Cr, Cd, Pb and Fe concentrations were analyzed in liver of black-legged kittiwake (BK), herring gull (HG), and northern fulmar (NF) chicks. There were significant species differences in the levels of NL, LF and lysosomal membrane stability. These parameters were not associated with the respective HOC concentrations. LF accumulation was associated with increasing Cr, Cd and Pb concentrations. HG presented the lowest lysosomal membrane stability and the highest. LF and NL levels, which indicated impaired lysosomes in HG compared to NF and BK. Lipid peroxidation was associated with HOC and Fe2+ levels. Specific HOCs showed positive and significant correlations with MDA levels in HG. The study indicates that contaminant exposure can affect lysosomal and lipid associated parameters in seabird chicks even at low exposure levels. These parameters may be suitable markers of contaminant induced stress in arctic seabirds.

(Table 1) Contents of tungsten and other metals in Fe-Mn nodules from the Pacific Ocean

Tungsten contents in iron-manganese nodules and crusts from different parts of the World Ocean, as well as its relationships with a number of chemical elements are under consideration. A trend to correlation of tungsten with Fe, Ti, W, Pb, and Co is noticed. Comparison of tungsten contents in the nodules and host sediments indicates its low geochemical mobility.

Fatty acids and intact polar lipids of laminated microbial sediments from St. Peter Ording, German Wadden Sea

Hidden for the untrained eye through a thin layer of sand, laminated microbial sediments occur in supratidal beaches along the North Sea coast. The inhabiting microbial communities organize themselves in response to vertical gradients of light, oxygen or sulfur compounds. We performed a fine-scale investigation on the vertical zonation of the microbial communities using a lipid biomarker approach, and assessed the biogeochemical processes using a combination of microsensor measurements and a 13C-labeling experiment. Lipid biomarker fingerprinting showed the overarching importance of cyanobacteria and diatoms in these systems, and heterocyst glycolipids revealed the presence of diazotrophic cyanobacteria even in 9 to 20 mm depth. High abundance of ornithine lipids (OL) throughout the system may derive from sulfate reducing bacteria, while a characteristic OL profile between 5 and 8 mm may indicate presence of purple non-sulfur bacteria. The fate of 13C-labeled bicarbonate was followed by experimentally investigating the uptake into microbial lipids, revealing an overarching importance of cyanobacteria for carbon fixation. However, in deeper layers, uptake into purple sulfur bacteria was evident, and a close microbial coupling could be shown by uptake of label into lipids of sulfate reducing bacteria in the deepest layer. Microsensor measurements in sediment cores collected at a later time point revealed the same general pattern as the biomarker analysis and the labeling experiments. Oxygen and pH-microsensor profiles showed active photosynthesis in the top layer. The sulfide that diffuses from deeper down and decreases just below the layer of active oxygenic photosynthesis indicates the presence of sulfur bacteria, like anoxygenic phototrophs that use sulfide instead of water for photosynthesis.

Chemistry of Jurassic/Cretaceous black shales

Black shale samples of Jurassic to Cretaceous age recovered during the 'Norwegian Shelf Drilling Program' between 1987 and 1991 from Sites 7430/10-U-01 (Barents Sea), 6814/04-U-02 (Norwegian Shelf near the Lofoten) and 6307/07-U-02 (Norwegian Shelf near Trondheim) were analyzed for major and trace elements. These laminated black shales are characterized by high total organic carbon (TOC) and total sulfur (TS) contents as well as by significant enrichments in several redox-sensitive and/or sulfide-forming trace metals (Ag, Bi, Cd, Co, Cr, Cu, Mo, Ni, Re, Sb, Tl, U, V, and Zn). Enrichment factors relative to 'average shale' are comparable to those found in Cenomanian-Turonian boundary event (CTBE) black shales and Mediterranean sapropels. The Re content is high in the studied black shales, with maximum values up to 1221 ng/g. Re/Mo ratios averaging 2.3*10**-3 are close to the seawater value. High trace metal enrichments and Re/Mo ratios close to the seawater value point to a dominantly anoxic and sulfidic water column during black shale formation. Interbeds with higher Re/Mo ratios, especially in high-resolution sampled core sections, point to brief periods of suboxic conditions. Additionally, enhanced Zn concentrations in the black shales from the Barents Sea support the assumption that hydrothermal activity was also high during black shale deposition. Trace metal signatures of black shales at different drill sites on a transect along the Norwegian Shelf are not only influenced by water depth but also by their location in the boreal realm. Metal enrichments are higher in the northern compared to the southern sites. Volgian (=Tithonian 151-144 Ma BP) black shales exhibit elevated trace metal contents in comparison to their Berriasian (144-137 Ma BP) counterparts. This probably reflects a change in the circulation pattern during periods of black shale formation. Therefore different paleoceanographic conditions, probably controlled by climatic change linked to the transgression of the paleo-sealevel and the North Atlantic opening, may have developed from the Volgian to the Berriasian.

Benthic foraminifera in Neogene laminated diatom ooze of ODP Hole 138-844C

Several widely correlatable intervals of laminated Thalassiothrix diatom mat deposits occur in Neogene sediments recovered from the eastern equatorial Pacific Ocean. The presence of laminated sediments in extensive areas of the deep open ocean floor raises fundamental questions concerning the cause of preservation of the laminations and the nature of the benthic environment during episodes of mat deposition. Traditional explanations for the preservation of laminations have centered on restriction of dissolved oxygen. Studies of benthic foraminifers through the laminated intervals show no evidence for an increase in absolute or relative abundance of species characteristic of a low oxygen environment, but rather a decrease in relative abundance of infaunal forms attesting to the impenetrability of the diatom meshwork formed by the interlocking Thalassiothrix frustules. These results support evidence from coring of the high tensile strength of the Thalassiothrix laminations suggesting that the diatom meshwork was of sufficient tensile strength and impenetrability to suppress infaunal benthic activity. Comparison of the relative abundances of foraminifers in the enclosing ôbackgroundö sediment of foraminifer nannofossil ooze and the laminated diatom oozes shows that some epifaunal species (e.g., Cibicides spp.) increase in relative abundance within the laminated sediment, whereas others (e.g., Epistominella exigua) show a marked decrease in relative abundance. Other species show more complex changes in abundance related to the occurrence of the laminated sediments, which may indicate a combination of controls that include the physical nature of the substrate and the amount of organic flux.

Minerals, native metals, and intermetallides in bottom sediments of the Markov Deep, Mid-Atlantic Ridge

Bottom sediments of the Markov Deep contain rather large (>0.1 mm) grains of native minerals and intermetallides of noble and nonferrous metals that can be concentrated in placers. Intermetallides of Pt and Fe are likely to be derivates of the gold-hematite-barite assemblage that forms at late (low-depth) stages of hydrothermal massive sulfide formation. Mineral association of native forms of lead, tin, and copper with Zn-bearing copper may be related to hydrothermal transformation of ultrabasic and basic rocks accompanied by massive sulfide copper mineralization. The association of these minerals of native elements in bottom sediments can also serve as a prospecting guide for sulfide mineralization both at the Sierra Leone site, in particular, and on the seafloor, in general.