Fauna associated with shallow-water methane seeps in the Laptev Sea

Abstract

The abundance of macrofauna was higher at methane seep stations compared to non-seep sites. Cluster analysis revealed five station groups corresponding to control area, <i>Oden</i> site and <i>C15</i> site (the latter represented by three groups). Taxa responsible for differences among the station groups were mostly widespread Arctic species that were more abundant in samples from methane seep sites. However, high densities of symbiotrophic siboglinids <i>Oligobrachia</i> sp. were found exclusively at methane seep stations. In addition, several species possibly new to science were found at several methane seep stations, including the gastropod <i>Frigidalvania</i> sp. and the polychaete <i>Ophryotrocha</i> sp. The fauna at control stations was represented only by well-known and widespread Arctic taxa. Higher habitat heterogeneity of the <i>C15</i> site compared to <i>Oden</i> was indicated by the higher number of station groups revealed by cluster analysis and higher species richness in <i>C15</i> trawl sample. The development of the described communities at the shallow-water methane seeps can be related to pronounced oligotrophic environment on the northern Siberian shelf.