Seabird density and predation on Arctic cod (Boreogadus saida) in Allen Bay in 2010

Seabirds feed heavily on Arctic cod Boreogadus saida during the summer in the Canadian Arctic but little is known of the interactions among birds while foraging and the factors that drive feeding behaviour. The objective of this study was to describe the relationship between seabirds and Arctic cod in a productive feeding area distant from breeding colonies. Transect surveys were completed using standardized count protocols to determine the density of seabirds in Allen Bay, Cornwallis Island, Nunavut. Shore-based observation sites determined seabird foraging behaviour associated with the presence of schools and environmental variables. The density of birds (156 bird/km**2) was high compared to that of other locations in the Canadian Arctic. Several bird species were more active early in the morning and with winds from the south, possibly due to an increase in Arctic cod feeding on zooplankton at the surface. Northern fulmars Fulmarus glacialis and black-legged kittiwakes Rissa tridactyla captured Arctic cod directly from the water; however, they lost nearly 25% of captures to glaucous gulls Larus hyperboreus and parasitic jaegers Stercorarius parasiticus. These kleptoparasitic seabirds benefited the most in Allen Bay obtaining as much as 8 times more Arctic cod than species capturing cod directly. Northern fulmars captured 3 times more Arctic cod from schools, and black-legged kittiwakes captured similar proportions of schooling and non-schooling cod. We conclude that non-schooling Arctic cod are as important as schooling cod as an energy source for seabirds in nearshore areas, such as Allen Bay, during the summer.

Fe-Mn nodules and host sediments from the Gulf of Finland

Distributions of major and trace elements in ferromanganese nodules, which are buried or exposed on the sea floor and in host sediments, were studied in ten concretion/sediment pairs by various physical and chemical methods. It was established that, in addition to Fe and Mn, a limited number of major and trace elements (P, Ca, Sr, Ba, Mo, Co, Zn, Ni, As, Pb, Sb, Tl, U, W, Y, and Ga) is accumulated with variable degree of intensity (relative to sediments) in the nodules. The maximal content of Mn in the nodules is 100 times higher than in the host sediments, whereas for all other elements listed above these ratios vary from more than one to 10-20. Manganese and, to a lesser extent, Ba and Sr are concentrated in the buried concretions. Other elements are primarily concentrated in concretions exposed on the sea floor. The occurrence mode of the concretions and compositional data on interstitial water suggest that metals in the concretions derive from seawater and suspended particulates, in addition to sediments. Burial of concretions in the sediment pile is accompanied by alteration of their composition, accumulation of Mn (relative to Fe), and loss of several associated metals.

Biometrics, fatty acid composition and stable isotopic ratios of five seabird species from Kongsfjorden, Svalbard

Marine birds are important predators in the marine ecosystem, and dietary studies can give useful information about their feeding ecology, food webs and oceanographic variability. The aim of this study was to increase our understanding of the diet and trophic level of the seabirds breeding in Kongsfjorden, Svalbard. We have used fatty acids and stable isotopes, both of which integrate diet information over space and time, to determine trophic relationships in marine food webs. Fatty acid compositions of muscle from Little auk (Alle alle), Brünnich's guillemot (Uria lomvia), Black-legged kittiwake (Rissa tridactyla), Northern fulmar (Fulmarus glacialis) and Glaucous gull (Larus hyperboreus) were determined and compared with their prey species. Canonical analysis (CA) showed that fatty acid composition differed among the five seabird species. Little auk, Black-legged kittiwake and Northern fulmar had high levels of the Calanus markers 20:1n9 and 22:1, indicating that these seabirds are a part of the Calanus food chain. Brünnich's guillemot differed from the other species with much lower levels of 20:1n9 and 22:1. Brünnich's guillemot is a pursuit diver feeding on fish and amphipods deeper in the water column, below 30 m. Glaucous gull also differed from the other seabird species, with a larger variation in the fatty acid composition indicating a more diverse diet. Trophic level analysis placed Little auk at the lowest trophic level, Brünnich's guillemot and Black-legged kittiwake at intermediate levels and Glaucous gull and Northern fulmar at the highest trophic level.

Chemical composition of Fe-Mn nodules and host bottom sediments along the submeridional profile across the Brazil Basin

Sedimentation and ore formation were studied in sediments from nine stations located along the 24°W profile in the Brazil Basin of the Atlantic Ocean. Bottom sediments are represented by mio- and hemipelagic muds, which are variably enriched in hydrothermal iron and manganese oxyhydroxides. As compared to bottom sediments from other basins of the Atlantic Ocean, the sediments in study are marked by extremely high manganese contents (up to 1.33%) and maximal enrichment in Ce. It was shown that the positive Ce anomaly is related to REE accumulation on iron oxyhydroxides. Influence of hydrothermal source leads to decrease of Ce anomaly and LREE/HREE ratio. In reduced sediments preservation of positive Ce anomaly and/or its disappearance was observed after iron and manganese reduction. REE contents were determined for the first time in the Ethmodiscus oozes of the Brazil Basin. Ore deposits of the Brazil Basin are represented by ferromanganese crusts and ferromanganese nodules. Judging from contents of iron, manganese, REE, and other trace elements, these formations are ascribed to sedimentation (hydrogenic) deposits. They are characterized by a notable positive Ce anomaly in the REE pattern. Extremely high Ce content (up to 96% of total REE) was discovered for the first time in the buried nodules (Mn/Fe = 0.88).

Concentration of persistant organic pollutants and mercury in seabird eggs collected in Norway

The main objective of this study was to investigate possible temporal trends of persistent organic pollutants (POPs) and mercury in eggs of herring gulls (Larus argentatus), black-legged kittiwakes (Rissa tridactyla), common guillemots (Uria aalge) and Atlantic puffins (Fratercula arctica) in Northern Norway. Eggs were collected in 1983, 1993 and 2003. Egg concentrations of POPs (PCB congeners IUPAC numbers: CB-28, 74, 66, 101, 99, 110, 149, 118, 153, 105, 141, 138, 187, 128, 156, 157, 180, 170, 194, 206, HCB, alph-HCH, beta-HCH, gamma-HCH, oxychlordane, trans-chlordane, cis-chlordane, trans-nonachlor, cis-nonachlor, p,p'-DDE, o,p'-DDD, p,p'-DDD, o,p'-DDT and p,p'-DDT) and mercury were quantified. Generally, POP levels decreased between 1983 and 2003 in all species. No significant temporal trend in mercury levels was found between 1983 and 2003.

Contents of P2O5, Corg, Sr, and Ba in phosphorites and host sediments from the Atlantic and Pacific oceans

Sr contents in phosphorites on shelves of the Southwest Africa, and of Chile and Peru increase with degree of their lithification, from 0.05 to 0.28% and from 0.13 to 0.16% respectively. Phosphorites from Pacific submarine seamounts have the average Sr content 0.11%, and bone phosphate from Pacific floor 0.13%. Shelf phosphorites are characterized by high correlation coefficients between Sr and P2O5 (R = +0.82) and constant Sr/P2O5 ratio (0.0084). In phosphorites from submarine sea-mounts and in bones from the ocean floor Sr/P2O5 ratio is only a little higher than a half of that in shelf phosphorites. This indicates specific and different genesis of phosphorites from submarine mountains. Ba content in recent phosphorites from the shelf of the Southwest Africa changes with increasing degree of lithification. At first their Ba contents rise from 0.031 to 0.188%, then they diminish to 0.016%, and thereafter again increase to 0.070%. This is due to successive predominance of one of the following processes going in different directions: co-precipitation with phosphate gels or formation of true separate Ba phase, loss of phosphate in crystallization and "self-purification" of concentrations, and surface adsorption. In Peru-Chile shelf phosphorites the average Ba content is 0.017%, in phosphorites from Pacific seamounts 0.192%, and in fossilized bones 0.010%.

(Table 1) Chemical composition of buried manganese noduls and host sediments of ODP Hole 138-854C

Two manganese (Mn) nodules were found in upper Miocene sediments in Hole 854C at a depth of 32.12 mbsf (Samples 138-854C-5H-1,0-2 cm, and -6H-1, 2-4 cm). In structure and composition, the lower nodule is similar to the Pleistocene surface nodules associated with radiolarian ooze from the Clarion-Clipperton Nodule Province. The upper nodule resembles those occurring on pelagic clay from the northern margin of that province.

Chemical composition of phosphorites and host sediments

Paleotemperature curves were drawn from oxygen-isotope ratios in CaCO3 of planktonic foraminiferal tests and by the micropaleontological method using quantitative relationships of their species. Two series of curves yield similar results. These data confirm that isotope composition of oxygen reflects primarily temperature, and not isotope composition in ocean water. Temperature of the upper layer of ocean water increased from north to south both during the last two glaciations and in the interglacials. All three sediment cores collected from different latitudes show approximately the same amplitudes of fluctuation of mean annual temperature during times of their accumulation, as determined independently by different methods; these amplitudes are estimated as 5-7°C.