Findings of Pogonophores (Annelida and Siboglinidae) in the Kara Sea Associated with the Regions of Dissociation of Seafloor and Cryogenic Gas Hydrates

The discovery of new occurrences of pogonophores Siboglinum sp. and Nereilinum sp. from the St. Anna Trough (northwestern portion of the Kara Sea) is described in this paper. Previously, occurrences of pogonophores (Crispabrachia yenisey and Galathealinum karaense) were reported in the southern part of the Kara Sea, in the estuary of the Yenisei River. Two areas in the Kara Sea where pogonophores were found coincide with the regions of distribution of two types of gas hydrates: oceanic seafloor gas hydrates, and gas hydrates associated with permafrost. Gas hydrate deposits in the permafrost are confined to the coastal regions of the Kara Sea. A methane flux forms in areas of dissociation of gas hydrates under the influence of river runoff. This methane source is vital for the survival of pogonophores. The existence of pogonophores in the St. Anna Trough indicates the presence of a methane flux associated with the inflow of Atlantic water, which causes dissociation of seafloor gas hydrates. The possible role of Arctic warming is apparent in both processes.