Structure and biogeography of hydrothermal vent communities
P.P. Shirshov Institute of Oceanology
117997 Moscow, Nakhimovsky pr., 36
e-mail: galkin@ocean.ru
Hydrothermal vent communities in different regions have been explored using deep-sea manned sub-mersibles "Pisces" and "Mir". Microdistribution of dominating animals has been studied by means of visual observations, photo and video analyses. In the present work, a generalized scheme of vent field zonation is proposed based on microdistribution patterns of vent organisms in different regions. In disjunctive biogeographic regions, established zones are marked by vicariating taxa and assemblages. Most previous biogeographic studies address the distribution of vent taxa. In our study we attempt to reveal general patterns of hydrothermal assemblages and communities distribution. Therefore we address the distribution of leading species dominating or codominating vent assemblages. According to the analysis, eight main biogeographic regions can be established in the Pacific, Atlantic, and Indian Oceans. Communities in disjunctive biogeographic regions are clearly distinguished, first of all, by the dominance of different taxa in the euthermal (near-went or "shimmering water”) zone. The analysis of vertical distribution of leading vent species reveals the most significant changes in community composition at the depths of 400-600, 1000-1500 and 2700-3000 m. It is concluded that geographic and bathymetric distribution patterns of vent communities demonstrate good concurrence with global-scale geographic and vertical distribution patterns of "normal" non-vent fauna.
