Title: Ecology of Meiobenthos Inhabiting the Local Biotopes of Gas Seeps in Coastal Waters of Crimea: Taxonomic Composition and Distribution in Bottom Sediments
Abstract: The present study reports results of investigation of meiobenthos from shallow-water gas seeps of Cape Tarkhankut (North-Western Crimea). The meiobenthic communities at the gas seeps have been found to be suppressed and less abundant than the zoobenthos in the surrounding seabed substrates. The density peaks of seep meiofauna are confined to the upper 0–3 cm layer, in contrast to the surrounding sands, where much more abundant meiofauna is located deeper in the sediment layer. Dominant and subdominant meiobenthic taxa are Nematoda, Foraminifera (Allogromiida), and Polychaeta. It is highly likely that among the meiofauna that was found in the seep marine sediments, there was a significant percentage of dead bodies from the surface layers, trapped inside the microbial mat because of the high growth rate of the bacterial substrate. Sulfidic seep sediments reduce the concentration of oxygen within the 1.5 m near-bottom layer. Seep sediments form specific “extreme” biotopes, where the environment rich in organic matter is combined with high concentrations of hydrogen sulfide and lack (or complete absence) of oxygen