Concentration function of the deep-sea vent benthic organisms

Distribution of macroions (Na, K, Ca, Sr), as well as trace metals (Fe, Mn, Zn, Cu, Co, Ni, Cr, Pb, Cd, Ag, As, Sb, Se, and Hg) were studied in the water samples collected in the shrimps and mussels habitats, as well as in the whole organisms and their different tissues. Samples were collected at the Rainbow and Broken Spur hydrothermal vent fields during the 50(th) cruise of the R/V. Besides most of these elements were determined in the Lost City warm fluids and certain organisms and minerals. There was no clear-cut distinction between major element concentrations in water of both the Broken Spur and Rainbow fauna habitats. Despite the end-member concentrations of some trace metals in the Rainbow vent fluids show enrichment relative to that in the Broken Spur, the difference between metal content in water is not so great in both the shrimps and mussels microhabitats at both fields. Among the metals the highest contents throughout all the fauna specimens were revealed for Fe (with peak concentrations up to n.105 mu g.g(-1)), followed by Zn and Cu (to n.104 mu g.g(-1)), Mn (to n.102 mu g.g(-1)). The Ni,As and Pb contents do not normally exceed some tens of mu g.g(-1). Concentrations of Cr, Cd, Ag, Sb and Se are not more than some mu g.g(-1), and Hg show the minimal content, commonly less than 0,5 mu g/g. This sequence of decreasing metal content in tissues corresponds to their concentrations in the surrounding water. In the dominant specialized taxa the main target organs of Fe, Zn, Mn, Co, Ni, Cu, Pb, Ag, As, Hg were maxillipeds of Rimicaris exoculata shrimps and gills of Bathymodiolus mussels. In spite of the low metal concentration were found in the mussels shells, the latter might serve as great reservoir of metals due to large biomass of mussel shell (87 % from the whole body dry weight). Mn being almost totally (97%) incorporated in shells, and the large portion (about 60% of whole body) of majority of metals studied was found in the mussel shells. Concentration factors of the trace metals in the mussels (Cwhole organism/Cwater) at the hydrothermal vent fields Broken Spur and Rainbow are decreased in the following order: Hg, Fe, Cu-(n.105) > Co, Pb-(n.104) > Cd, Zn, Ni Ag-(n.103) > Mn, As Sb-(n.102)