Lyudmila L Demina

Trace metal accumulation in carbonate biominerals of the Atlantic Ocean

New data on trace metal (As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb) distribution in carbonate biominerals formed in geochemically different oceanic environments are discussed. Calcite shells of shelf and deepwater hydrothermal vent mussels as well as planktic foraminifers and pteropods from the central Atlantic Ocean have been studied. The variability in concentrations of most trace elements between different groups of calcifying organisms are usually within one order of magnitude, except for Fe and Mn, the elevated contents of which in microfossils are caused by post-sedimentation interaction. Different groups of calcifying organisms demonstrate a biogeochemical uniformity in trace metal accumulation during the biomineralization processes.

Trace elements in organisms of different trophic groups in the White Sea

Concentrations of trace elements (Fe, Mn, Cu, Pb, Ni, Cr, Cd, As, Co, and Se) have been studied in different trophic groups of organisms: primary producers (seston, presented mostly by phytoplankton), primary consumers (mesozooplankton, macrozooplankton, and bivalves), secondary consumers (predatory macrozooplankton and starfish), and consumers of higher trophic levels (fish species), inhabiting the coastal zone of Kandalaksha Bay and the White Sea (Cape Kartesh). The concentrations of elements differ significantly for the size groups of Sagitta elegans (zooplankton) and blue mussel Mytilus edulis, as well as for the bone and muscle tissues of studied fish species, Atlantic cod Gadus morhua marisalbi and Atlantic wolffish Anarhichas lupus. The concentrations of all the studied elements were lower among the primary consumers and producers, but increased again at higher trophic levels, from secondary consumers to tertiary consumers (“mesozooplankton → macrozooplankton Sagitta elegans” and “mussels → starfish”). Ni and Pb tended to decline through the food chains seston→…→cod and mesozooplankton→…→stickleback. Only the concentrations of Fe increased in all the trophic chains along with the increase of the trophic level.

The geochemistry of deepwater particulate matter over the hydrothermal field at 9°d50′ N (the East Pacific Rise)

The results of geochemical studies of particulate matter in the water mass over the hydrothermal field at 9°50′ N on the East Pacific Rise are presented. The particulate matter was tested in background waters, in the buoyant plume, and in the near-bottom waters. The contents of Si, Al, P, Corg, Fe, Mn, Cu, Zn, Ni, Co, As, Cr, Cd, Pb, Ag, and Hg were determined. No definite correlations were found between the ele-ments in the background waters. Many of the chemical elements correlated with Fe and associated with its oxyhydroxides in the buoyant plume. In the near-bottom waters, microelements are associated with Fe, Zn, and Cu (probably, to their sulfides formed under fluid mixing with seawater). The matter precipitated in a sed-imentation trap was similar to the near-bottom particulate matter in the elemental composition.

Occurrence forms of trace metals in recent bottom sediments from the White and Barents Seas

For the first time based on determination of the geochemical occurrence forms of trace metals the main processes that control the accumulation of elements (Al, Mn, Fe, Mo, Cr, Ni, Co, Cu, Pb, Cd, and As) in the recent sediment cores from the White Sea and Barents Sea were quantified. A high-resolution study of the bottom sediment cores allowed us to estimate the short-term variations (periodicity of 10–15 years) in the accumulation of metals to reveal the periods of maximum Fe and Mn contents in the amorphous hydroxides fraction, which serve as effective adsorbents of the trace elements majority, including heavy metals. The Mn/Fe ratio in the amorphous hydroxides phase can be considered as geochemical indicators of early diagenesis.

First Russian conference on the International Geotracers Program

113 A meeting as part of the International Geotracers Program was conducted for the first time in Moscow in late November (http://www.geotraces.org/). The meeting involved two interrelated and complementary actions. The first of them, a scientific conference, was organized and carried out at the Shirshov Institute of Oceanology of the Russian Academy of Sciences on November 27–29, 2012. The second one was a round table discussion entitled Prospects for Exploration of the Arctic Ocean: International Expedition 2015. It took place on November 30 within the framework of the 2nd International Complex Exhibition for Ship building and the Use and Exploration of Water Resources entitled The World Ocean 2013 at the Cro cus City international exhibition center. GEOTRACES is an international program that has existed since 2007 under the aegis of the Scientific Committee on Oceanic Research (SCOR). The main objective of the program is to study the biogeochemi cal cycles of trace elements and their isotopes in the oceans: the quantitative assessment of their sources, transport, transformation in the water’s column, and fate of these elements in marine settings around the globe. It is known that a number of trace elements (Fe, Mn, Cd, Co, Zn, and others) control the biochemical processes in living organisms and influence the bio productivity of marine ecosystems. This research will improve knowledge of trace metals, carbon and nutri ent cycles in the open and coastal ocean, and their response to changing global environments. The pro gram seeks to understand biogeochemical processes and cycles of trace elements including their exchange between land, sediments, atmosphere, and seawater. The conference at the SIO RAS was interdepart mental and international in character. About eighty researchers, including young ones, from Russian sci entific institutes took part: the SIO RAS, AARI, IGEM RAS, POI FEB RAS, Sevmorgeo Company, VNIIOkeangeologia, VNIRO, and Vernadsky Insti tute of Geochemistry and Analytical Chemistry of the Russia Academy of Sciences. Fourteen leading scien tists from the United States (Woods Hole Oceano graphic Institute, MIT, Lamont Doherty Geological Observatory of Columbia University, University of Miami, and Norfolk University), Great Britain (Oxford University), Germany (Alfred Wegener Insti tute), and Sweden (Naturhistoriska riksmuseet) took part in the Conference too. Eleven presentations were given by the foreign participants, and 18 studies were reported by Russian scientists, among which were eight young researchers and postgraduate students. Mainly young participants presented 15 reports during the poster session. The structure and main research objectives of the GEOTRACES program, as well as the results of geochemical studies of the water column in oceanic transects, were reported by Prof. G. Henderson (Oxford University, Great Britain). Prof. R. Anderson (Lamont–Doherty Laboratory of Columbia Univer sity in the United States) showed in his report how important the exploration of the global geochemical processes at the continent–ocean interface, where the main supply of the majority of the chemical elements into the ocean takes place, is. He quantitatively evalu ated the contribution of river runoff to the composi tion of the ocean’s waters too. Prof. E. Boyle (MIT) focused his report on the results of isotopic geochem ical research in the North Atlantic for revealing the cli matic changes. Prof. G. Cutter (Norfolk University) described the basic principles underlying the scientific results of the GEOTRACES program. These are necessity to comply with the protocols of “noncon taminating” sampling and analyzing with the help of high sensitivity instruments, regular participation in intercalibrations, and the use of international standard samples for performing analytical procedures. Great interest was expressed by the conference par ticipants in the report of Academician A.P. Lisitzin (SIO RAS). He described his concept of an approach to studies of global geological geochemical processes in the ocean: the investigation of the contribution of six geospheres (the fluxes of sedimentary material from the atmosphere, criosphere, hydrosphere, bio sphere, endosphere, and anthroposphere) into the seventh geosphere, namely, the sedimentosphere. The geospherical approach, which is being developed by the scientific school of Academician A.P. Lisitzin, is an indispensable tool for understanding the compli First Russian Conference on the International Geotracers Program