Factors Controlling the Trace Metal Distribution in Hydrothermal Vent Organisms

Despite the numerous published data, the evaluation of the various conditions, influencing the trace metal distribution and accumulation in the different hydrothermal organisms, is not completed up till now. In this chapter we aimed to clear out the influence of the main factors, affecting the trace metal bioaccumulation in the deep-sea hydrothermal vent biota: environmental factors, acting outside the organisms, and biological ones, acting inside the organisms and within the biological communities. Among the environmental conditions there are such site-specific differences as depth, temperature, and fluid chemical composition that control trace metal concentrations in water of the biotope, as well as mineralogical features of substratum. Meanwhile the biogenic factors include stage of ontogenesis, species differences, trophic level and feeding type, and etc. For this purpose we consider data on the Fe, Mn, Zn, Cu, Cd, Pb, Ag, Ni, Co, Cr, As, Se, Sb, and Hg concentrations in the benthic organisms inhabiting the following hydrothermal vent fields at the Mid-Atlantic Ridge (MAR): Menez Gwen, Rainbow, Lost City, Broken Spur, as well at the 9°50′N at the East Pacific Rise (EPR), and the Guaymas Basin (Gulf of California). To clarify some of the influencing factors, we have aimed to summarize the available data on factors that control the trace metal distribution in hydrothermal vent organisms, including not only Bathymodiolus mussels, but also other dominant organisms, such as Rimicaris shrimps, vestimentiferan tube worms Riftia pachyptila, whose feeding strategy relies on microbial symbiotrophy. Distribution patterns of some trace metals studied in different taxa gave an evidence of the influence of environmental and biological parameters on their bioaccumulation in the hydrothermal vent organisms.